Component Engineering Training Course

Component Engineering Training Course
This Training Course has been compiled and is presented by Spur Electron Ltd. Component Engineering Training Course

WHAT IS COMPONENT ENGINEERING?
It is an individual or group which provides the project team with a broad knowledge and experience of EEE components, including: Electronic and semiconductor theory and principals Materials, construction and manufacture Space component procurement systems Quality and screening requirements Component Engineering Training Course

HIGH RELIABILITY COMPONENTS
DEFINITION : A component is defined as :- The smallest sub-division of a system which cannot be further sub- divided without destroying its function. EEE stands for :- E Electrical, e.g. Resistors, Capacitors, Connectors E Electromechanical, e.g. Relays, Switches, Actuators E Electronic, e.g. Integrated Circuits, Transistors, Diodes Component Engineering Training Course 6

HIGH RELIABILITY COMPONENTS (CONT.)
Europeans tend to use the word “Component”, whereas the Americans use the term “Part”. Both terms will be found within this presentation, and should be considered as synonymous. Europeans use the term “High Reliability Components, Americans often use the term “Hi-Rel Part”. Again the terms are synonymous. High Reliability components are those in which a very high degree of confidence can be placed that they have stable characteristics and a working life in excess of the mission requirements. This definition is flawed, in that the components are manufactured to a standard set of requirements, whilst mission duration's vary considerably. Component Engineering Training Course 7

A decade ago mission duration's were typically 3 to 5 years. Today mission duration's of up to 15 to 20 years are required. The US Military market has led the field in specifying reliability standards. In the mid 1960’s, various government agencies identified that defects, able to be screened out, were resulting in an equipment failure rate of about 1% per thousand hours. In-depth failure analysis identified the predominant failure mechanisms. Component Engineering Training Course 8

The Solid State Applications Branch of the RADC was assigned the task of developing a screening procedure to remove the infant mortality failures, which led to the high failure rates previously encountered. In 1968 the RADC staff developed MIL-STD-883. Component Engineering Training Course

THE BATHTUB CURVE Component Engineering Training Course

OPERATING ENVIRONMENT FOR SPACE COMPONENTS
Environmental Extremes: Temperature Radiation Mechanical Stresses Vacuum Component Engineering Training Course

THE EUROPEAN APPROACH TO SPACE COMPONENTS
Component Engineering Training Course

ORIGINS OF THE ESA/SCC SYSTEM
Need for Pan-European Specification System for EEE Components realized by ESRO, prior to the formation of ESA. Until this need was recognized and acted upon a range of differing specification systems were being used Component Engineering Training Course

ORIGINS OF THE ESA/SCC SYSTEM (CONT.)
This resulted in: - No standardization. - Wide variations in test and inspection philosophies. - Huge variances in manufacturers quoted price and delivery. - Extreme difficulty in assessing comparative quality and reliability of delivered components. Component Engineering Training Course

In 1971 ESRO through its Joint Programmes and Policy Committee (JPPC) set up the Space Components Coordination Group (SCCG) on an interim basis as an advisory group. Over 30 years later, this interim group is still operating. In 1973 the JPPC approved the SCCG Terms of Reference. The SCCG now set about the generation of a series of basic policy documents. Component Engineering Training Course

These documents were approved by the SCCG at its plenary meeting in November 1973 and submitted to the JPPC for its approval. Before approval by the JPPC, ESRO and ELDO were merged into the present day ESA. ESA then abolished the JPPC, and the SCCG was placed under the direct authority of the Director General. Component Engineering Training Course

This new status entailed new terms of reference and redefinition of responsibilities for both the SCCG and the Director General. The placement of the SCCG under the Director General's control was finally approved in 1976. This ESA policy has been superseded by ESCC and SCAHC Component Engineering Training Course

OBJECTIVES OF THE ESA/SCC SYSTEM
The basic objectives of the ESA/SCC System as defined by ESA/SCC Document No “Object and Basic Rules of the ESA/SCC System” are: - Political. The promotion of a European System of Specifications for Space Components. - Technical. The System capable of being integrated with other international systems. - Commercial. Promotion of the production in Europe of Components suitable for Space Application. Component Engineering Training Course

OBJECTIVES OF THE ESA/SCC SYSTEM
Standardisation Interchangability Improvement cost/schedule planning Component Engineering Training Course

SCCG ACHIEVEMENTS By the early 1980s the SCCG had achieved a very complete ESA/SCC System comprising over 1000 specifications and had assisted in the qualification of some 350 components manufactured by a total of 40 European manufacturers. In spite of this success the European user community were very concerned that ESA/SCC components were significantly more expensive than space qualified components from the US. There was also a major concern that the SCCG was overly bureaucratic and the ESA/SCC System over specified technical requirements. In 1993 ESA published a technical paper recommending some major areas of review and modification. This lead to the formation of SCAHC. Component Engineering Training Course

SCAHC What was SCAHC? The Space Components Ad Hoc Committee (SCAHC) was established by ESA in October 1994 It comprised of experts from all the main space sectors within Europe. i.e. ESA, National Space Agencies, Commercial Space Organisations, Space Industry and Space Component Manufacturers. In addition the European Commission was also represented. The SCAHC task was to formulate a long term programme for space components that would enhance European competitiveness in the world market. Component Engineering Training Course

SCAHC RECOMMENDATIONS
In a final report released in 1995 the SCAHC made ten recommendations: R1 – Maintain the ESA/SCC System of specifications including related qualification programmes and quality assurance approach in order to meet users needs and market trends. R2 – Standards and specifications for components shall reflect a higher degree of delegation from suppliers with reduced customers controls. R3 – Wherever possible, European component specifications and standards should be based on international standards and should be promoted to obtain international recognition. Component Engineering Training Course

SCAHC RECOMMENDATIONS (CONT.)
R4 – Implement a stringent system for the reduction of diversity of components for use in space, based on the usage of a European Preferred Parts List, giving preference to European components. R5 – Establish a reliability system for European space Components R6 – Establish an information Exchange system on component data with access for all European users. R7 – Enable the mutual recognition of industrial performance in the various component disciplines, including component engineering, radiation hardness assurance, auditing and inspection (with formal certification of the latter), through provision of the relevant and regular training opportunities. Component Engineering Training Course

SCAHC RECOMMENDATIONS (CONT.)
R8 – Improve the availability of strategically important components, giving preference to European sources (Microprocessors, MMICs etc). R9 – Implement, in full partnership with the users, manufacturers, commercial customers and agencies, a European Space Component Research and Technology Programme assuring coherence with other market sectors, and cost effectiveness. R10 – Establish a permanent Component Steering Board (CSB) representing the interests of all the European space partners, to monitor market trends, to provide financing and to overview the technology programmes and its synergies, and advise on necessary policy changes. Component Engineering Training Course

SCSB ACHEIVEMENTS TO DATE
In the 7 years since the SCAHC recommendations were made progress has been slow but reasonably successful. Using the recommendations as a guide we can demonstrate the following achievements. R1 Maintain but improve the ESA/SCC system. Two major contracts awarded. One to review the structure and organisation, relatively successful, the SCSB now responsible for the policy and the Executive responsible for the day to day operation. Second contract to carry out in depth review. Results very controversial. However general agreement appears to have been reached, some changes already incorporated, some still to be made. Component Engineering Training Course

ACHEIVEMENTS TO DATE (CONT.)
R2 Reduce Customer Controls. Partially achieved by the reduction of deliverable documentation, now incorporated into the system. R3 Gain international recognition for the system NASA now accept ESA/SCC Level B as equivalent to US MIL Level S R4 Establish a European PPL Now available on ESCIES (see later) R5 Establish a European reliability system Problem found to be an international concern. NASA and NASDA are currently involved in seeking solutions. R6 Establish Information Exchange Database Now Established (see ESCIES). Component Engineering Training Course

ACHEIVEMENTS TO DATE (CONT.)
R7 Enable mutual recognition. Set of training programmes envisioned. Still not fully initiated. R8 Improve availability of strategically important components. Incorporate into CTB activities, see R9 below. R9 Establish a Component Technology Board. The CTB is well established and has developed it’s own five year plan. However funding availability is a major concern. R10 Establish a Space Components Steering Board (SCSB). SCSB Charter was formally signed on 8th October 2002 Component Engineering Training Course

MR. RODOTẦ SIGNS THE CHARTER

ESA/SCC STILL THE STANDARD
Even though the ESCC is intended to replace the ESA/SCC System, it hasn’t yet happened and is unlikely to be complete for a number of years. In the meantime the ESA/SCC System continues to be the preferred standard. Component Engineering Training Course

RELATIONSHIP TO THE ECSS SYSTEM
The ESA/SCC specification system is a self contained subset of the ECSS System in that ECSS-Q-00 identifies that components shall be procured by means of the ESA/SCC specification system, thus making it a part of the ECSS system. ECSS-Q-60 is the Level II document applicable for EEE components. This document clearly identifies the requirement for maximum use and preference towards the ESA/SCC Specification System. Component Engineering Training Course

ESA/SCC DOCUMENT REF/001 This identifies the existence and status of all documents and specifications issued on behalf of the Director General of ESA. It is regularly updated and issued to all registered users of the ESA/SCC System. At this time, this document comprises a total of >1000 documents and specifications, including:- Percentage of Total Documents Level 0 Series - Object and Basic Rules 0.5% Level 1 Series - Organization, Procedures and Implementation 1.0% Level 2 Series - Basic Specifications 10.5% Level 3 Series - Generic Specifications 3.0% Level 4 Series - Detail Specifications 86% Component Engineering Training Course

SCC DOCUMENTARY SYSTEM

LEVEL 2 DOCUMENTS BASIC SPECIFICATIONS
These specifications define the basic requirements for a process, document or test method. There is no standard table of contents owing to the wide range of topics addressed. Employs either a 5 or 7 digit code, i.e. either Internal Visual Inspection Internal Visual Inspection of Integrated Circuits Component Engineering Training Course

BASIC SPECIFICATIONS (EXAMPLES)
TEST METHODS 22900 Total Dose Steady-State Irradiation Test Method 23800 Electrostatic Discharge Sensitivity Test Method 24800 Resistance to Solvents of Marking Materials and Finishes Component Engineering Training Course

BASIC SPECIFICATIONS (EXAMPLES) (CONT.)
INSPECTION METHODS Internal Visual Inspection of Integrated Circuits 20500 External Visual Inspection 21400 Scanning Electron Microscope Inspection Component Engineering Training Course

BASIC SPECIFICATIONS (EXAMPLES) (CONT.)
SYSTEM REQUIREMENTS 20100 Requirements for Qualification of Standard Electronic Components for Space Application 21500 Calibration System Requirements Evaluation Test Programme for Surface Acoustic Wave (SAW) Devices 22800 ESA/SCC Non-Conformance System 24600 Minimum Quality System Requirements Component Engineering Training Course

LEVEL 3 DOCUMENTS GENERIC SPECIFICATIONS
- Generic meaning “CLOSELY RELATING TO ANY GROUP OR CLASS”. - It defines the general Inspection, Test and Documentation requirements for a group of components. - Employs a Four Digit Code, and may refer to a Family of components or a Sub-Family of components. An example to illustrate its use:- EXAMPLE 4001 40 = Family Code (Resistor Family) 01 = Sub-Family Code (Metal Film) Component Engineering Training Course

GENERIC SPECIFICATION CONTENTS
Defines the general requirements for a component family, including: Qualification Approval Capability Approval Procurement Lot Acceptance Testing Delivery Inspection & Test Schedules Data Documentation Component Engineering Training Course

GENERIC SPECIFICATION
TABLE OF CONTENTS 1. Introduction 2. Applicable Documents 3. Terms, Definitions, Abbreviations, Symbols and Units 4. Requirements 5. Production Control for Qualification and Capability Approval 6. Final Production Tests 7. Burn-in and Electrical Measurements 8. Qualification Approval, Capability Approval and Lot Acceptance Tests 9. Test Methods and Procedures 10. Data Documentation 11. Delivery 12. Packaging and Despatch -- Test Flows -- -- Sampling Plans -- Component Engineering Training Course

GENERIC SPECIFICATIONS (EXAMPLES) (CONT.)
3009 Capacitors, fixed, chips, ceramic dielectric types I and II 4001 Resistors, fixed film 5000 Discrete Semiconductor Components 9000 Integrated Circuits, Monolithics. Component Engineering Training Course

LEVEL 4 DOCUMENTS DETAIL SPECIFICATIONS
Defines the detail requirements for a component type, including:- Ratings Physical and Electrical Characteristics Test and Inspection Data TABLE OF CONTENTS 1. General 2. Applicable Documents 3. Terms, Definitions, Abbreviations, Symbols and Units 4. Requirements 5. Tables 6. Figures 7. Appendices Component Engineering Training Course

DETAILED SPECIFICATION EXAMPLES
3009/004 Capacitors, fixed, chips, ceramic dielectric type I. 4001/011 Resistors, fixed film, Non hermetically sealed. 5000/005 Diodes, silicon, fast recovery, avalanche rectifiers, 400W. 9000/001 Monolithic microwave integrated circuits (MMIC), GaAs, Travelling wave amplifier. Component Engineering Training Course

COMPONENT NUMBERING - RADIATION IDENTIFICATION

RADIATION IDENTIFICATION

OTHER PROCUREMENT SYSTEMS
CECC NASA US MILITARY Component Engineering Training Course

CECC The Cenelec Electronic Components Committee (CECC) System for electronic components of assessed quality became operational in 1973. Its object is to facilitate trade by the harmonization of specifications and quality assessment procedures for electronic components. Components produced under CECC requirements carry a special mark and are accepted by all member states. 15 countries participate in the CECC System:- Austria, Denmark, France, Belgium, Finland, Germany, Ireland, Italy, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom. Component Engineering Training Course

CECC LOGO Component Engineering Training Course

CECC (Cont.) There are a number of different types of approval available within CECC. Manufacturers, specialist contractors, distributors and independent test houses, can each be approved for their particular capability. Each approval carries its own award of a certificate. Component Engineering Training Course

CECC Qualification Approval, CECC 00 114:part II
Enhanced Assessment of Quality, CECC :part IV Capability Approval, CECC :part III Technology Approval, CECC :part VI Process Approval, CECC :part V Distributor Approval, CECC :part 1 Test Laboratory Approval, CECC :part 1 Component Engineering Training Course

NASA The National Aeronautics and Space Administration, NASA, was formerly established in 1958, to plan and execute the US civil space programme. It comprises about a dozen major facilities, employing around 25,000 civil servants. Component Engineering Training Course

MAIN NASA SITES Goddard Space Flight Centre (GSFC)
Jet Propulsion Laboratory (JPL) Kennedy Space Centre (KSC) Marshall Space Flight Centre (MSFC) Component Engineering Training Course

NHB NASA programmes are controlled through a top level handbook, NHB This document is imposed on all contractors. It details the requirements for the control, selection, procurement, testing and application of all flight and mission essential EEE components. The hand book is divided into two major sections, Programme Management and Component Requirements. Component Engineering Training Course

NHB (Cont.) The Programme Management Section also identifies the requirements to provide data to NASA in electronic form. The Component Requirements Section addresses the detailed topics directly related to components including, selection and specification, screening, parts lists, critical parts, derating, GIDEP, traceability, handling, packaging and storage, qualification and quality conformance tests, receiving inspection and manufacturer surveillance. Component Engineering Training Course

GSFC PREFERRED PARTS LIST
There are numerous PPLs used within the US space industry, however the GSFC PPL is considered as one of the best. It contains a list of preferred parts in two quality levels: Grade 1 for higher quality/critical applications and Grade 2 for less demanding applications. Component Engineering Training Course

US MILITARY STANDARDS In the 1950s the US government, in conjunction with the American armed forces, introduced a series of documents to standardize the screening flows for electrical and electromechanical components. The system has continued to evolve, and now includes electronic components. The objectives being: Total product Interchangeability Configuration control Efficiency of volume production Maximum number of approved sources These aims have in the most part been achieved Component Engineering Training Course

MIL-STD-883 In the early 1960s the rapidly growing Integrated Circuit industry was coming of age. It was recognised that the level of defects attributable to Infant Mortality could be significantly reduced if a standardized screening flow were introduced. The Solid State Applications Branch of the Air Forces, Rome Air Defence Center (RADC) was given the task. Component Engineering Training Course

MIL-STD-883 OBJECTIVE To create an economically feasible, standardized IC screening flow, to achieve equipment failure rates of :- 0.085% per 1000hrs., class B (Military) 0.004% per 1000hrs., class S (Space) Component Engineering Training Course

883 ORIGINAL SCREENING FLOWS
Originally there were three screening flow classes, A,B and C:- Class A, critical non-repairable applications Class B, high reliability, maintainable Class C, non-critical ground applications Class A, was superseded by Class S in 1977 Class C, was dropped in 1984, lack of use. Component Engineering Training Course

883 DETAILED SPECIFICATIONS
MIL-STD-883 is a collection of test methods designed to look at specific reliability and quality concerns affecting semiconductor products. The specification covers Environmental, Mechanical and Electrical test methods. In addition 883 also covers a range of procedures. Component Engineering Training Course

883 SCREENING REQUIREMENTS

883 SCREENING REQUIREMENTS (CONTD)

38510 - QUALIFICATION AND QUALITY CONFORMANCE TESTING
Each of the flows requires qualification and quality conformance testing. The quality conformance testing frequency is defined in MIL-M-38510 (JAN product) and paragraph 1.2 of 883 (non-JAN product). Quality conformance testing is divided into 5 groups, A, B, C, D and E. Group A : Sample electrical testing Group B : Sample constructional tests Group C : performed only on class B product. Sample reliability testing Group D : Sample package related testing Group E : Only required where a radiation hardness requirement identified. Component Engineering Training Course

MIL-STD SUMMARY 883 provides a valuable tool for the Military and Space semiconductor user. However it does not provide the specific device electrical requirements necessary to achieve standardization. This is established by MIL-M-38510 Component Engineering Training Course

MIL-M-38510 Concurrent with the development of MIL-STD-883, RADC developed MIL-M-38510 MIL-M-38510, establishes the procedures which a manufacturer must follow to have his products listed in the Qualified Parts List Also published a set of performance and electrical parameters, (slash sheets) Component Engineering Training Course

OBTAINING QPL LISTING A manufacturer must meet the following requirements before obtaining QPL listing Line Certification as defined within MIL-STD 976 Device Qualification. There are two levels of QPL listing. Part II requirements are significantly less than Part I. Part II listing was established to expedite manufacturers into the QPL. Component Engineering Training Course

OBTAINING QPL LISTING (Cont.)
To obtain Part II listing, all line certifications must be complete and significant electrical, design and constructional test data submitted, and approved. Part I listing requires significant additional testing and therefore takes much longer to complete. Component Engineering Training Course

QUALIFICATION BY EXTENSION
There are three ways to extend device or package qualification. Die related testing Die extension Package extension In addition it is possible to extend qualification to differing lead finishes. Component Engineering Training Course

PART NUMBERING AND MARKING
MIL-M devices have a unique part numbering system. e.g. JM38510/AAABBCDE: J = JAN prefix M = MIL-M-38510 / = Replaced by hardness assurance letter, when applicable Component Engineering Training Course

PART NUMBERING AND MARKING (Cont)
AAA = Slash sheet no. BB = Component no. on the slash sheet C = Screening level S or B D = Component package type. E = Lead finish e.g. JM38510/10107SGC = Slash sheet 101 device 07(LM118) Class S, in 8 pin, TO-99 package with gold finish. Component Engineering Training Course

MIL-I-38535 Over the past decade, standards have not been able to keep pace with the rapidly changing technologies. MIL-M-38510, which is very successful for simpler components was not suited to complex technologies such as ASICs, gate arrays and VLSI components. As a result the Qualified Manufacturers List (QML) approach was implemented through MIL-I-38535 The QML approach is to qualify the manufacturer, rather than his specific products. Component Engineering Training Course

MIL-I (Cont.) The manufacturer adopts a Total Quality Management (TQM) approach to his business. This applies from the initial design phase through to customer feedback. The objective is to demonstrate, through Statistical Process Control (SPC), continuous improvement. Component Engineering Training Course

MIL-S-19500 To date the information related to the US-MIL System has related to ICs. Similar reliability concerns are held with respect to other EEE components. This section deals with discrete semiconductor devices, incl. FETs, bipolar transistors, diodes, rectifiers and thyristors. In 1959 the United States Navy Bureau of Ships, created MIL-S-19500, which performs the same function for discrete semiconductor products, that MIL-M provides for ICs. MIL-S was tailored to work with the JEDEC numbering system. Component Engineering Training Course

MIL-S (Cont.) The JEDEC numbering system is simple in that a three or four digit number was preceded by an XN, where X is one less than the number of active element terminations on the device. Thus a diode has two terminations, X = 1. Transistors generally have three terminations, thus X = 2 Dual transistors were also given a 2N number, even though their 6 pins would suggest a 5N number. Suffixes were added to provide additional information e.g. M for matched pair. Component Engineering Training Course

MIL-S (Cont.) In 1963 the Navy decided that it would be better to have a separate specification for detailed test methods. In 1964 MIL-STD-750 was published as a “how to” of test methods for MIL-S MIL-S establishes general requirements Detailed requirements are specified in detail specifications. 4 levels of PA requirements are specified. JAN,JANTX,JANTXV and JANS. Component Engineering Training Course

MIL-S QUALIFICATION Before any supplier can deliver any level of JAN semiconductor products, he must undergo a formal qualification cycle. This qualification cycle is much like that already identified for MIL-M Once qualified the manufacturer is listed in QPL To retain QPL listing the manufacturer has to submit, each year, a summary of all of the quality conformance testing that has been completed. If any changes are made to the QPL listed components that affect performance, quality, appearance, reliability or Interchangeability, re-qualification may be required. Component Engineering Training Course

MIL-S-19500 SCREENING REQUIREMENTS

MIL-S-19500 SCREENING REQUIREMENTS (Cont.)

MIL-STD-202 MIL-STD-202 establishes uniform methods of testing for component parts including: Capacitors, resistors, switches, relays and transformers. The standard is only intended to apply to small parts. The test methods have been prepared to serve several purposes:- To give test results equivalent to those existing in actual service To provide a standardized, uniform approach to testing To provide a range of test methods, that can be applied to components not covered by an approved military drawing Component Engineering Training Course

MIL-STD-202 (Cont.) Classes of tests. The tests are divided into three classes:- 101 to 199, Environmental 201 to 299, Physical characteristics 301 to 399, Electrical Characteristics Component Engineering Training Course

MIL-STD-202 (Cont.) Revision of test methods are indicated by a letter following the method number Thus the first revision to test 101 is 101A, the second 101B etc. Test sequences are not mandatory, but are provided to give guidance. Component Engineering Training Course

MIL-STD-202 (Cont.) Component Engineering Training Course

COMPONENT MANUFACTURERS SPECIFICATIONS
Nearly all component manufacturers have their own internal standards which form the basis for any other customer specification placed upon them. These standards cover basic electrical, mechanical and environmental characteristics. Increasingly manufacturers are also setting standard screening and test requirements, from which they are not prepared to deviate. Component Engineering Training Course

COMPONENT MANUFACTURERS SPECIFICATIONS (Cont.)

ESA/SCC TEST AND INSPECTION REQUIREMENTS

ESA/SCC TEST AND INSPECTION REQUIREMENTS
This section covers the various tests and inspections which form part of the ESA/SCC Specification System for high reliability components. In the ESA/SCC System the inspections are divided up into: - Special In-process Controls - Final Production Tests - Burn-in - Qualification Tests - Lot Acceptance Tests Component Engineering Training Course

INDIVIDUAL TESTS Test Category of Test
Probable Procurer’s Inspector Involvement SEM Inspection Internal Visual Inspection External Visual Inspection Electrical Screening Tests High Temperature Stabilisation Bake Temperature Cycling Thermal Shock (in Air) Constant Acceleration Particle Impact Noise Detection (PIND) Seal Test Burn-in Radiography Permanence of Marking High Temperature Storage Bond Pull Die shear Mechanical Shock Test Vibration Thermal Shock Moisture Resistance Solderability Terminal Strength Operating Life Destructive Non-destructive Destructive Sequence Reviews report Performs test Unlikely Witnesses test Review report Witnesses test and/or inspects devices Component Engineering Training Course

SPECIAL IN-PROCESS CONTROLS
Special tests and inspections which are carried out during manufacturing with the intention of checking specific processing steps or sub-components of the final device. These processing steps or sub-components are ones which have: - Been shown to be critical in producing high reliability components and - which cannot be tested or inspected at the end of production. Component Engineering Training Course

WLA A wafer lot is a set of wafers that been manufactured together and therefore are from the same diffusion, oxidation and metallisation lot. Wafer lot acceptance (WLA) is a series of inspections carried out on samples of die from a wafer lot. The samples must be taken from particular locations within the wafer. These positions are described in ESA/SCC Basic Specification No or MIL-STD-883 Method Component Engineering Training Course

SAMPLE SELECTION 1. Proper sample selection is an important part of the examination method. 2. Statistical techniques using random selection are not practical, because of the large sample needed. 3. Sample selection criteria are based on minimizing test sample size yet maintaining confidence in the examination. 4. The selection of wafers is based on their position in the wafer holder. Dice at specific locations on those wafers are selected to show worst case metallisation processing defects. Component Engineering Training Course

DIE SELECTION PLAN Component Engineering Training Course

DIE SAMPLE EXAMINATION
1. All four edge directions shall be examined for each type of contact window or metallisation step. 2. Viewing angles & direction shall be chosen so as to accurately assess the quality of metallisation. 3. For multi-layered-metal systems, it will be necessary to remove the layers one at a time to expose the next underlying layer for examination. Component Engineering Training Course

SCANNING ELECTRON MICROSCOPE

METALLISATION STEP Component Engineering Training Course

EXAMPLE OF INSPECTION DEFECTS

ACCEPTANCE/REJECTION CRITERIA
1. Rejection of dice shall be based on lot process orientated defects. 2. Rejection shall not be based on workmanship and other type defects such as scratches, smeared metallisation, tooling marks, etc. Such defects will be rejected at Pre-cap inspection. Component Engineering Training Course

WLA DOCUMENTATION 1. Photographic
- minimum of 3 SEM, 1 each for worst case metallisation, oxide step & contact window. 2. Information traceable to each Photograph - Manufacturer’s name & address - name & address of test house or laboratory - SEM operators/inspectors identification no. - Date of SEM inspection & photograph - component part, type or reference number - SEM inspection lot number or code - area forming subject of photograph - magnification - accelerating voltage - viewing angle Component Engineering Training Course

FINAL PRODUCTION TESTS
The final step in the manufacture of most types of components is the final sealing of the component package. The Final Production Tests are a series of tests and inspections carried out just before and just after the components are sealed. Purpose is to look for: Anomalies in the production lot Component Engineering Training Course

INTERNAL VISUAL Before sealing the component it should be examined optically to verify that internal materials, design and construction are in accordance with the applicable acquisition document. In the case of integrated circuits the inspection should be performed at both high and low magnification. Component Engineering Training Course

INTERNAL VISUAL Component Engineering Training Course

BOND STRENGTH TEST This test measures bond strengths,evaluates bond strength distributions or determines compliance with specified bond strengths required of applied acquisition documents. The specifications include table and graphs giving the different bond strengths required for the diameter and material of the bond wires. A record should be made of the force at which the bond wire breaks and the applicable code for the site of break. Component Engineering Training Course

BOND STRENGTH AND DIE SHEAR TESTER

BOND PULL TEST Component Engineering Training Course

BOND STRENGTH TEST Component Engineering Training Course

DIE SHEAR TEST Component Engineering Training Course

DIE SHEAR STRENGTH This test is used to determine the integrity of materials and procedures used to attach semiconductor die or surface mounted passive elements to package headers or other substrates. Failure criteria is based on: 1. Measure of force applied to die. 2. Type of failure (if failure occurs) 3. Visual appearance of residual die attach. Component Engineering Training Course

DIE SHEAR STRENGTH Component Engineering Training Course

HIGH TEMPERATURE STABILISATION BAKE
Many components initially display variations in some of their electrical parameters, but these parameters become stable after a short time at high temperature. The ESA/SCC Generic Specification No requires devices to be stored for 48 hours at the maximum storage temperature. Component Engineering Training Course

TEMPERATURE CYCLING AND THERMAL SHOCK

PARTICLE IMPACT NOISE DETECTION (PIND)

PARTICLE IMPACT NOISE DETECTOR

PIND RESPONSE Component Engineering Training Course

RADIOGRAPHIC INSPECTION

RADIOGRAPHY The purpose of Radiography is, to confirm the following:-
Absence of foreign material within the package. Correct location/mounting of internal elements. Correctly made internal/external connections. Proper sealing of the device. Radiography has the following drawbacks:- Aluminium bond wires and silicon are almost transparent to X-Rays Additional tests are required to determine whether foreign material within the package is loose. Due to unfavourable positioning of the device, a defect maybe undetectable Component Engineering Training Course

FINE LEAK TESTING 1. The most widely used fine leak tests are radioactive tracer and helium leak detection methods 2. The radioactive tracer test is most sensitive but test is complex and hazardous and the equipment is very expensive 3. For the helium test the components are placed in a bombing chamber and pressurized in helium gas. The pressure and time are dependant on the volume of the package. 4. The components are then transferred to a detector which detects the outgassing helium. Component Engineering Training Course

TYPICAL CONDITIONS FOR FINE LEAK TEST

BOMBING CHAMBER Component Engineering Training Course

FINE LEAK TESTING Component Engineering Training Course

GROSS LEAK TESTING 1. If the component needs to be preconditioned then it is placed in D80 perfluorinated fluid and placed in the bombing chamber under pressure for a specified amount of time. 2. The component is then immersed in D02 perfluorinated fluid at 125°C. A stream of bubbles is looked for. 3. Another gross leak test that is used in some circumstances i.e. for glass diodes is the dye penetrant test. Here the component is placed in a dye penetrant fluid in the bombing chamber. After removal and cleaning it is inspected with ultraviolet light. Areas where the dye has entered inside cavities are easily located. Component Engineering Training Course

TYPICAL CONDITIONS FOR THE GROSS LEAK TEST

GROSS LEAK TEST Component Engineering Training Course

EXTERNAL VISUAL INSPECTION
A low magnification inspection of the external surfaces of parts. PURPOSE: “To check the external component materials, construction and workmanship for compliance to ESA/SCC”. Requirements taken from ESA/SCC Basic Specification series Performed after stress tests and as a final inspection prior to delivery. Generally the final inspection activity. Can be performed on an AQL basis of 1% in final production tests. At other times, e.g. screening, it is performed on 100% basis. Although dimensional check is generally applied on AQL of 1%. Component Engineering Training Course

EXTERNAL VISUAL PHOTOGRAPHS

EXTERNAL VISUAL INSPECTION SHALL INCLUDE THE FOLLOWING EXAMINATIONS
1. Marking 2. Metal Surface 3. Case 4. Feed-throughs 5. Brazed joints 6. Leads Component Engineering Training Course

EXTERNAL VISUAL INSPECTION REQUIREMENTS
Ensure Material and External construction are in accordance with detail specification. External surfaces should be clean. No corrosion. No peeling of finishes. No holes or cracks. No colour change. Except for :Tinned surfaces which may show some discolouration after endurance or high temperature storage. :Even discolouration of body after high temperature storage. Component Engineering Training Course

EXTERNAL VISUAL INSPECTION REQUIREMENTS (CONT.)
Dimensional check - In accordance with the detail specification. Marking - Legibility and permanence. Soldered/Braised Joints - Reject if: Solder surface not clean and smooth. Evidence of cracks or voids. Incomplete solder flow or coverage. Balling of solder. Foreign matter in solder. Component Engineering Training Course

DIMENSION CHECK Component Engineering Training Course

ELECTRICAL SCREENING TEST AND
BURN-IN Component Engineering Training Course

ELECTRICAL SCREENING TESTS
Electrical measurements carried out to confirm that the components do meet the electrical requirements specified for them and to remove from the lot any which do not. It is a check for any electrical degradation which has occurred in components as a result of any stress tests. The tests can be a full set of parameter measurements at room temperature, or at high and low temperature or just a measurement of certain critical parameters to look for changes. The details of which measurements must be carried out at any point and what results are acceptable are given in the detail specification for each component type. Component Engineering Training Course

BURN-IN The purposes of Burn-in are two fold:
- Removal of infant mortalities - To check the PDA Component Engineering Training Course

HIGH TEMPERATURE REVERSE BIAS
HTRB is designed to check the ability of a device to continuously block a voltage under conditions accelerated by both elevated temperatures and high voltages. The HTRB is particularly useful when screening defective MOS devices. The primary failure modes for this stress are the leakage currents Idss and Igss. Component Engineering Training Course

QUALIFICATION AND LOT ACCEPTANCE TESTS

LOT ACCEPTANCE TESTS Full ESA qualified parts undergo Lot Acceptance Testing (LAT) on samples from the production lot. This yields greater reliability assurance with respect to environmental, mechanical assembly and endurance of the devices. Within the ESA/SCC system the Lot Acceptance Tests are specified in Chart V of the appropriate Generic Specification and indicate which tests are performed, how many parts are required for each test and how many failures are permitted for each of the tests. Component Engineering Training Course

CONSTANT ACCELERATION

HIGH TEMPERATURE STORAGE
The test is performed by placing the components in a high temperature chamber for the specified time at a specified temperature. Its purpose is to determine whether the components are degraded by a period of time at their maximum rated storage temperature. After completion of the storage test, any degradation of the components is detected by using appropriate end point measurements such as leak testing, electrical testing and visual inspection. Component Engineering Training Course

MECHANICAL SHOCK TEST The components are mounted on a shock machine and subjected to a series of mechanical shocks. The purpose of this test is to check the mechanical integrity of the package, particularly the die mounting, wire bonding and package sealing. Component Engineering Training Course

VIBRATION TEST Component Engineering Training Course

THERMAL SHOCK Components are alternately immersed in liquids at high temperature and at low temperature. The number of cycles, the immersion and transfer times, the liquids to be used and the temperatures to be used are given in the appropriate specifications. The purpose of the test is to subject the components to severe thermal stressing to reveal any mechanical weaknesses. Any degradation caused by this test is usually detected by subsequent end point measurements such as leak testing, electrical measurements or external visual inspection. Component Engineering Training Course

MOISTURE RESISTANCE Components are subjected to a number of cycles of combined high temperature and humidity. Purpose of the test: Corrosion - Moisture ingress. Component Engineering Training Course

OPERATING LIFE The components are electrically stressed while simultaneously subjected to a high temperature. → accelerated ageing → simulating the normal operating life in a matter of weeks. Arrhenius Equation: R=Ae -Eα/kT Electrical measurements, leak testing, visual inspection performed at the end of the test to establish whether there is any degradation. Component Engineering Training Course

MARKING PERMANENCY TEST

PERMANENCE OF MARKING - 1

PERMANENCE OF MARKING - 2

SOLDERABILITY This test method is to evaluate the The ability of the terminations to be: 1. Wetted by a coating of solder. 2. To produce a suitable solder fillet. The termination is dipped in flux and allowed to dry for a few seconds, then dipped in a solder pot which is at the specified temperature for secs. The termination is then cleaned in IPA and examined at a magnification of 10-15x. Component Engineering Training Course

SOLDERABILITY Acceptance criteria:
1. At least 95% covered with a continuous new solder coating. 2. Pinholes, voids, porosity, nonwetting, or dewetting must not exceed 5% of the total area. Component Engineering Training Course

SOLDERABILITY Component Engineering Training Course

LEAD INTEGRITY There are various tests for determining the integrity of device leads, welds and seals. 1. Straight tensile loading. 2. Application of bending stresses. 3. Application of torque or twisting stresses. 4.Application of peel and tensile stresses The individual test conditions need to be specified. Component Engineering Training Course

LEAD INTEGRITY Failure criteria:
The components should be examined at a magnification of 10 – 20x after the removal of stress any evidence of: 1. Breakage 2. Loosening 3. Relative motion between lead and body 4. Adhesion failure of solder pads shall be considered a failure. Component Engineering Training Course

LEAD INTEGRITY Component Engineering Training Course

MICROSECTION Components are microsectioned after potting in a suitable epoxy resin so that a microscopic examination can be undertaken for the purpose of accurately locating, identifying and characterising all the internal structural features of the samples in order to judge any defects against the criteria of the specification. Typical components that require microsection are: Diodes Capacitors Relays Isolators Fuses Component Engineering Training Course

MICROSECTION OF A CAPACITOR

ESA/SCC → ESCC Following a SCAHC recommendation produced after consultation with the space industry, ESCC Specifications are being phased in to replace the ESA/SCC specifications. The ESA/SCC Generic Specifications contain five charts which are:- Chart I Testing Levels Chart II Final Production Tests Chart III Burn-in and Electrical Measurements Chart IV Qualification Tests Chart V Lot Acceptance Tests In ESCC Generic specifications, these will be replaced by:- Chart F1 General Flow Chart Chart F2 Screening Tests Chart Chart F3 Qualification and Periodic Tests Component Engineering Training Course

A TYPICAL COMPONENT PROCUREMENT PROGRAMME

PROCUREMENT SYSTEM SELECTION
Generally, on Larger programmes, the prime contractor selects the method by which the EEE components will be procured. The basis for the selection will depend upon the programme cost, meeting the agreed schedule, and compliance to the technical requirements. Procurement possibilities are usually assessed under three separate headings: - Self Procurement Co-ordinated Procurement Centralised Procurement Component Engineering Training Course

SELF PROCUREMENT Overall higher costs:
No cost sharing between contractors MOQs More man power required Component Engineering Training Course

COORDINATED PROCUREMENT
Minimum: Loose association of users combining procurements Maximum: Almost Centralised were all parts are procured through the same system to the same specifications. Control is in theory maintained by the prime contractor who would receive schedules, specifications, non-conformances evaluation reports and other technical input from users. Component Engineering Training Course

CENTRALISED PROCUREMENT
All EEE component requirements are delivered to the Prime contractors managements team who then consolidate the requirements into a project procurement allocation list, which once reviewed and approved by the Procurement Management is passed to the Procurement agent to carry out the actual procurement. If properly managed Centralised procurement offers: - All the advantages of minimal cost - Maximised control and uniform quality Component Engineering Training Course

COMPARISON OF THE COORDINATED AND CENTRALISED APPROACHES

PARTS PROCUREMENT COSTS PER SATELLITE MODEL

LEAD TIMES IN PROCUREMENT
Device Type Procurement Lead Time Capacitor 24 – 26 weeks Connector 24 weeks Diode IC Stock to 26 weeks Relay 32 weeks Resistor Stock to 12 weeks Transistor Component Engineering Training Course

PROCUREMENT PHASES PRE-PROCUREMENT: Those activities necessary to be completed before purchase orders can be placed upon the component manufacturers. PROCUREMENT: The actual manufacture, test and inspections necessary to meet the purchase order requirements. POST PROCUREMENT: Those activities required to provide confidence that the requirements have been met and to prepare the components for installation. Component Engineering Training Course 2

TYPICAL PROCUREMENT PHASES
Component Engineering Training Course 3

PRE-PROCUREMENT PHASE
The objective of this phase is to complete those activities necessary to confidently place purchase orders for EEE components. Often this phase is not properly carried out, leading to severe problems and project delays later in the programme. Those areas most commonly neglected are:- Risk Management Component Selection Component Type Reduction. Evaluation. Obsolescence Management Specification preparation, integration and modification. Component Engineering Training Course 4

PRE-PROCUREMENT PHASE (CONT.)
Component Engineering Training Course 5

COMPONENT SELECTION The equipment design engineers are responsible for the selection of EEE components. However it is the task of the component engineers to provide support and assistance in the activity, particularly with respect to standardization, quality and reliability issues. The main tool provided to assist in the selection process is the Preferred Parts List (PPL). Component Engineering Training Course 6

THE EUROPEAN PREFERRED PARTS LIST
ECSS-Q provides the rules for establishing the list of preferred and suitable components to be used by European manufacturers of spacecraft hardware and associated equipment. A copy of the ECSS-Q can be down loaded from the ECSS home page ( The EPPL can be found on the ESCIES website. Component Engineering Training Course

EPPL (CONT.) Component Engineering Training Course 7

EPPL (CONT.) Component Engineering Training Course

PPL (CONT.) Contractual enforcement of the PPL has sometimes been achieved, however this places a major responsibility upon the PPL developer to ensure that the components in the PPL are:- Capable of satisfying a wide range of design applications Mature in the chosen technologies to be suitable for flight applications Considered to have a significant utilization Have an acceptable test or usage history Available from approved manufacturers Component Engineering Training Course

PPL (CONT.) In addition to the above it is also essential that the PPL also:- Takes into account known single user applications Identifies new technologies for evaluation (Part 2) Is maintained and regularly updated Component Engineering Training Course

QML Component Engineering Training Course

QML (CONT.) Component Engineering Training Course

PARTS LIST REVIEW Parts list should be reviewed to check:
Availability of qualified parts. Lead times to component delivery. Part costs and minimum order quantities (MOQ) Part type reductions (with implicit per part cost reductions for buying greater quantities of a given type) Number of DPAs necessary - Does the EEE parts plan allow limited DPA on similar part types / date codes Radiation test requirements LAT levels necessary The need for any constructional analyses Evaluation plans (life test etc.) Component Engineering Training Course

PLASTIC ENCAPSULATED MICROCIRCUITS CUSTOM OFF THE SHELF DEVICES
AND CUSTOM OFF THE SHELF DEVICES Component Engineering Training Course

PEMs Space projects are increasingly interested in using PEMs.
There are a number of reliability related issues with using COTS PEMs for space including: Traceability Lot Conformance Screening Change Control Radiation Hardness Obsolescence Component Engineering Training Course

SCREENING TESTS There are a number of tests that can be performed to increase confidence in device reliability. Some procurement agents believe that minimal screening is necessary and that over and above the usual screening requirements it is necessary to perform little more than: Radiographic Inspection Scanning Acoustic Microscopy (CSAM) Component Engineering Training Course

SCANNING ACOUSTIC MICROSCOPY

CSAM IMAGE OF DELAMINATION

LIFTED BONDS AT THE DIE SURFACE

RADIOGRAPHIC INSPECTION

PEMs But… There are other failure mechanisms and potential concerns.

Tg of PEM PLASTICS Component Engineering Training Course

Screening If you need confidence approaching that which you might have from space qualified parts you’ll need to look at performing… DPA including Tg (Sample) 1st Electrical Test (100%) Temperature Cycling (Sample) Radiographic (100%) CSAM (100%) Electrical Test (100%) Dynamic Burn-In (100%) Dynamic Life Test (Sample) End Point Electrical Test(100%) HAST (Sample) Post HAST electrical Test (Sample) Vibration (Sample) Component Engineering Training Course

COST IMPACT OF UPSCREENING
NEPAG have produced a cost model to assess the relative costs of buying space grade parts with the cost of upscreening COTS. The model does not include non-recurring engineering (NRE) charges so the model is very conservative. NRE can run to hundreds of thousands of dollars for complex microcircuits. Component Engineering Training Course

NEPAG COST MODEL PER LINE ITEM

RELIABILITY ASSURANCE LEVELS
NASA has traditionally categorized space level EEE parts by reliability assurance level: Level 1 = Most reliable, intended for use in mission critical and life support applications (US MIL Class S, V or K or ESA Level B LAT2) Level 2 = Moderate reliability for general applications (US MIL Class B,Q or H or ESA Level C) Level 3 = Non-mission essential, higher risk applications (MIL-STD-883 Compliant) Component Engineering Training Course

IMPACT OF UPGRADING Component Engineering Training Course

RADIATION ASSURANCE COTS parts are not designed or manufactured to meet any particular level of radiation hardness for TID or SEE. Radiation is a very real issue with plastic devices because plastic is an insulator and may allow charge to build up. Radiation Hardness Assurance a must be performed on every lot further adding to the overall cost. The lack of lot homogeneity for COTS may require testing of larger samples also driving up costs. Component Engineering Training Course

CONCLUSION COTS microcircuits are not a low cost alternative to inherently space level parts. Component Engineering Training Course

To find out more… NEPAG Website:
Mike Sampson’s paper to ESCCON 2002: Component Engineering Training Course

PLASTIC DECAPSULATION

TYPE REDUCTION Type reduction is carried out to minimize the number of component types with similar functions. Failure to carry out this activity reduces the possibility to standardize. This, in turn, results in significant cost increases and increased delivery times. It is the component engineers responsibility to ensure that this task is carried out thoroughly. Component Engineering Training Course

COMPONENT EVALUATION ECSS-Q-60A states. If valid and acceptable qualification of a component type cannot be demonstrated, a component evaluation and approval testing programme shall be implemented. This programme is required to cover the following elements:- - Design and Application Assessment - Constructional Analysis - Manufacturer Assessment - Evaluation Testing Reduction or omission of any of the above steps may be approved if sufficient evidence is provided to justify the omission. Component Engineering Training Course

DESIGN AND APPLICATION ASSESSMENT
The objective of the Design and Application assessment is to:- Identify those electrical parameters essential for the intended application Justify why a fully qualified component cannot be used Component Engineering Training Course

CONSTRUCTIONAL ANALYSIS
Typically carried out on a sample of three representative components, the Constructional Analysis is intended to demonstrate that:- The standard of fabrication and assembly has been fully assessed. All potential failure modes are identified. No materials or processes have been employed which might result in premature failure of the component. Component Engineering Training Course

TYPICAL CONSTRUCTIONAL ANALYSIS FLOW
6 OF, SAMPLES PHYSICAL DIMENSIONS ELECTRICAL MEASUREMENTS EXTERNAL VISUAL INSPECTION HERMETICITY MARKING AND SERIALISATION X - RAY DE - CAPPING INTERNAL VISUAL INSPECTION MICROSECTIONING BOND STRENGTH TEST DIE SHEAR TEST Component Engineering Training Course

MANUFACTURER ASSESSMENT
This assessment, carried out against the appropriate ESA/SCC checklist, includes, but is not necessarily limited to, an audit of:- The overall manufacturing facility, and its organization and management. The manufacturers system for inspection and manufacturing control. The production line used for the component. Component Engineering Training Course

SPECIFICATION WRITING
Maximum use should always be made of existing specifications But, projects sometimes require devices which: There is no existing hi-rel specification Require additional testing Testing is excessive Component Engineering Training Course

SPECIFICATION WRITING
If the required parts fall outside of existing qualification limits they can be covered by extension and a cover sheet is all that is required. Specifications are prepared around the manufacturers datasheet and sent to the manufacturer see whether the requirements are possible and to the customer for agreement on the details. This cycle of negotiation continues until full agreement is reached. Specifications are usually written in the same format as some existing specification such as those from MIL or ESA. It is necessary to establish which type of format is most desirable to the customer. Component Engineering Training Course

OBTAINING SPECIFICATIONS
Most space specifications are available free of charge through the internet. The following sites may prove useful: ESA Specifications: http// US Military Specifications: Military and others (J-STD, IEC etc.) Component Engineering Training Course

EVALUATION TESTING Carried out after completion of the previously identified assessments, evaluation testing is intended to determine which inspection and tests are the most appropriate to provide confidence that the component when fully meeting the procurement specification requirements, will also meet the intended mission requirements. The types of testing to be considered include:- Electrical stress Mechanical stress Environmental stress Assembly capability testing Radiation testing Component Engineering Training Course

EVALUATION REPORT The Evaluation Report comprises:- Design Assessment
Constructional Analysis Manufacturer Audit Evaluation test report Component Engineering Training Course

PART APPROVAL DOCUMENTS (PAD)
Once the Pre-procurement technical activities are complete, it is of great value, and mandatory for ESA programmes to summarize the technical baseline. The Part Approval Document (PAD), provides an excellent base for this summary. Component Engineering Training Course

PART APPROVAL DOCUMENTS (PAD) (CONT.)

ATTRITION AND SPARES Allowance must be made for the provision of attrition and spares, the following excerpt from a procurement plan is an example of such a policy:- Component Engineering Training Course

OBSOLESCENCE MANAGEMENT
How can we minimise the affects of obsolescence? At the design phase the selection of the components must have the maximum predictable life span. Procure sufficient components for the intended programme and any envisaged ‘follow on’ programmes Monitor the availability of components used in the design and allow the implementation of ‘last time buy’ Joining obsolescence groups can yield opportunities to discuss ‘work around solutions’ with other engineers Component Engineering Training Course

OBSOLESCENCE MANAGEMENT (CONT.)
There are manufacturers who specialise in buying die stock from manufacturers who are phasing out product types. Assembly and Test Houses can package and screen product if die is available. Component Engineering Training Course

RISK MANAGEMENT Component Engineering Training Course

RISK MANAGEMENT CONCEPT
Risk management is a four step systematic and iterative process for optimising resources in accordance with the project’s risk management policy. Four Steps: Step1 - Define risk management implementation requirements Step2 - Identify and assess the risks Step 3 - Decide and act Step 4 - Monitor, communicate and accept risks Component Engineering Training Course

STEP 1 – DEFINE RISK MANAGEMENT IMPLEMENTATION REQUIREMENTS SEVERITY CONSEQUENCE SCORING SCHEME

STEP 1 – DEFINE RISK MANAGEMENT IMPLEMENTATION REQUIREMENTS LIKELIHOOD SCORING SCHEME

EXAMPLE OF A RISK INDEX SCHEME

STEP 2: IDENTIFY AND ASSESS RISKS
Purpose: To identify each of the risk scenarios, to determine based on the output of step 1, the magnitude of the individual risks and finally, to rank them. Data from all project domains are used (managerial, programmatic, technical) Component Engineering Training Course

STEP 3: DECIDE AND ACT Purpose:
To analyse the acceptability of risks and risk reduction options according to the risk management policy, and to determine the appropriate risk reduction strategy. Determine measures for reducing the risk Determine the risk reduction success/failure criteria. Select the best risk reduction measure Component Engineering Training Course

STEP 4:MONITOR, COMMUNICATE AND ACCECPT
Purpose: To track, monitor, update, iterate and communicate risks and finally to accept the risks. Periodic assessment of risks Illustration of risk trend over project evolution Implementation of new risks as they arise or become evident Component Engineering Training Course

EXAMPLE OF A RISK TREND Component Engineering Training Course

READY TO ORDER Component Engineering Training Course

THE PURCHASE ORDER Component Engineering Training Course

PERFORMANCE OF AN INSPECTION

PLANNING OF INSPECTIONS
Ensure that the manufacturer knows that you are coming and that he is aware of the exact purpose of the of the inspection Check that all essential documents are available. If previous history files are available, check for previous problems found and how they were dealt with. It is important to be as knowledgeable as possible. Component Engineering Training Course

DOCUMENTARY ORDER OF PRECEDANCE
To undertake an inspection the procurers inspector should use the following documentation. Whilst undertaking an inspection it is possible that conflicts between documents could occur. In such circumstances the procurer’s inspector shall take the documentary order of precedence as indicated below:- Purchase order or contract Detail Specification Generic Specification Basic Specification Other reference documents Component Engineering Training Course

SAMPLE INSPECTION Within the ESA/SCC System sampling inspection is performed for certain tests. Three approaches may be found within the system:- Fixed sample size Sample size dependent upon lot size, and used to assess the lot on an AQL Sample size dependent on lot size and used to assess the lot based upon an LTPD Use of sampling methods is of limited statistical significance due to discontinuous nature of space component production. Component Engineering Training Course

SAMPLE INSPECTION (CONT.)
Acceptable Quality Level (AQL), example ESA/SCC Detail specification 5101/011 Electrical measurements at high temperature Tests to be performed on a sample basis, Inspection Level II, Table II-a, AQL = 1.0 of MIL-STD-105, minimum 10% parts to be measured. Using MIL-STD-105 , lot size 450, inspection level II requires sample size letter H, Now, using the ‘Single Sampling Plan for Normal Inspection’ code H and AQL 1.0%, gives sample 50 accept on 1, fail on 2. Component Engineering Training Course

SAMPLE INSPECTION (CONT.)
Lot Tolerant Percentage Defects. (LTPD) Example. Electrical measurements at room temp. on 450 2N6033 Transistors ESA/SCC 5203/026 a.c. parameters sample basis LTPD 7 or less. Using LTPD sampling plan, lot sizes greater than 200, LTPD 7 or less, The sample size is to be a reasonable size for the lot under inspection. e.g. Sample size 32 accept on 0 defects. Sample size 55 accept on 1 defect Summary LTPD = 7 Sample size = 32 Acceptance no. = 0 Rejection no. = 1 Component Engineering Training Course

INSPECTIONS SUMMARY Inspect strictly in accordance with the requirements Do not allow personal feelings, lack of time or previous history affect your judgement. Report your findings in reasonable detail . Never try to correct a discrepancy, raise a non-conformance. Always report the sampling plan used. Obtain the manufacturers representatives signature to your report. Never lose your temper. If you cause any damage, of any sort, report it immediately. Component Engineering Training Course

QUALIFICATION TESTING
Qualification Testing of a component must be in accordance with Chart IV of the relevant ESA/SCC Generic Specification. The Qualifying Space Agency may accept relevant and recent valid test data as replacing part, or all, of the Chart IV test requirements. Components subjected to the qualification testing phase are considered as having undergone destructive testing. The disposition of the qualification test lot is the responsibility of the Qualifying Space Agency. Component Engineering Training Course

TYPICAL FINAL PRODUCTION AND BURN-IN TESTS
FINAL PRODUCTION TESTS (Ref. ESA / SCC 9000 Chart II) (For Integrated Circuits) BURN-IN AND ELECTRICAL MEASUREMENTS (Ref. ESA / SCC 9000 Chart II) (For Integrated Circuits) Productions and Controls in accordance with Section 5 of the Generic Specification Parameter Drift Values (Initial Measurements) Internal Visual Inspection Power Burn-in Special In-Process Tests Parameter Drift Values (Final Measurements) Final Assembly, Encapsulation Stabilisation Bake Electrical Measurement at High and Low Temperature Mechanical + Environmental Tests Electrical Measurement at Room Temperature Seal Test (optional) Radiographic Inspection Electrical Measurement at Room Temperature Seal Test (Fine and Gross Leak) Electrical Measurement at High and Low Temperature (optional) External Visual Inspection Marking (plus serialisation for Level B) Check for Lot Failure (P.D.A.) External Visual Inspection Sampling Level II - A.Q.L. 1%) To Figure 9 Dimension Check Component Engineering Training Course

TYPICAL GENERIC SPECIFICATION QUALIFICATION TEST
100 Components Environmental / Mechanical Subgroups nnn Assembly / Capability Subgroups Endurance Subgroup nnnnnnnnnnninnn 15 Components 15 Components 15 Components 15 Components 15 Components Shock Test Temperature Cycling Solderabilty Operating Life High Temperature Storage Vibration nnnnnnnnnnn Thermal Shock nnnnn Permanence of Marking Electrical Measurements during Endurance Testing Electrical Measurements during Endurance Testing Constant Acceleration Moisture Resistance Terminal Strength Seal Test Seal Test nnn Seal Test Seal Test External Visual Inspection Electrical Measurements at Room Temperature Electrical Measurements at Room Temperature Internal Visual Inspection External Visual Inspection External Visual Inspection Bond Strength (1) External Visual Inspection External Visual Inspection Die Shear (1) 2 2 1 1 1 2 1 3 Component Engineering Training Course

INCOMING INSPECTION Once the devices arrives at the procurement agent. A Receiving Inspection Record (RIR) is produced which details of the purchase order, manufacturer, the procurement specification , lot numbers, date codes etc. The RIR also records: Package inspection Parts Inspection Data Review DPA Allocation Comments, observations, NCRs etc are recorded on the RIR Component Engineering Training Course

DATA REVIEW Component Engineering Training Course

DPA The objective of DPA is to provide an engineering evaluation of a device lot to determine compliance with specified constructional requirements, evaluate processes, workmanship and the material consistency of the product. The sample size is not statistically relevant but is intended to be a snapshot of the quality of the lot. A typical sample size is 3 randomly selected pieces but it can be dependant on factors such as cost, quantity of lot and customer requirements. Component Engineering Training Course

DPA DATA RECORDS Each DPA should be assigned a unique number for identification purposes and each component serialized if it has not been already. DPA data records should include: 1. Outline of the DPA procedure. 2. DPA summary sheet. 3. DPA check list. 4. DPA data sheets. 5. Original X-rays and photographs 6. Other data or analysis results which support findings Component Engineering Training Course

COMPONENT TYPES FOR DPA
DPA is required to be performed on samples from each delivered date code of the types listed below: Discrete semiconductors Integrated circuits Filters Variable capacitors/resistors Ceramic capacitors Tantalum capacitors Relays and switches Crystals Hybrids High voltage components High frequency components Opto-electronic components Component Engineering Training Course

EXAMPLE DPA FLOW FOR AN INTEGRATED CIRCUIT
External visual MIL-STD-883 method Mechanical parameters Manufacturers data sheet Fine leak MIL-STD-883 method cond A1 Gross leak MIL-STD-883 method cond C Radiographic MIL-STD-883 method 2012 PIND MIL-STD-883 method 2020 Marking permanence ESA/SCC 24800 Lead integrity MIL-STD-883 method cond B2 Solderability MIL-STD-883 method Internal visual MIL-STD- 883 method cond A SEM inspection MIL-STD-883 method Wire bond strength MIL-STD-883 method cond D Die shear strength MIL-STD-883 method Component Engineering Training Course

EXAMPLE DPA FLOW FOR A DIODE
External visual MIL-STD-750 method Mechanical parameters MIL-PRF-19500/*** Marking permanency ESA/SCC 24800 Solderability MIL-STD-750 method 2026 Internal visual MIL-STD-750 method Microsection MIL-STD-750 method Component Engineering Training Course

NON CONFORMANCE CONTROL
The European Space Agency has a very precise way of dealing with non conforming product and if it is an ESA project that is being worked upon then it is a requirement that the ESA/SCC approach to NCRs is followed. This is defined in ESA/SCC 22800 Many companies consider this to be too rigid and adopt a more relaxed approach. Component Engineering Training Course

INITIATION OF THE ESA/SCC NON-CONFORMANCE SYSTEM
There are two distinct ways of initiating the ESA/SCC Non-Conformance System:- • The Chief Inspector of the ESA/SCC qualified manufacturers, • The user of the ESA/SCC Specification System, The former is not only required to initiate the Non-Conformance System but also to take responsibility for the initiation of the system for any non-conformance brought to their attention from any source. The latter also have a major responsibility toward the system, in that they are users of the ESA/SCC System. Component Engineering Training Course

THE MANUFACTURER'S CHIEF INSPECTOR
There are clearly defined occasions when the Manufacturer's Chief Inspector must initiate the non-conformance procedure, i.e.:- • During final production tests. • As a result of a PDA failure • As a result of Qualification failure • As a result of LAT failure. Component Engineering Training Course

THE ESA/SCC SYSTEM USERS
Any person in attendance at an ESA/SCC Qualified Manufacturer's premises to conduct or witness a test or inspection on ESA/SCC qualified component lots will raise a NCCS on finding the following: • Any serious breach of quality or safety procedures. • Clear evidence that the Process Identification Document (PID) has been modified without ESA/SCC approval. • Evidence that the lot submitted for inspection does not originate from the master lot identified. • Should the manufacturer refuse to accept the rejection of any defects found. Component Engineering Training Course

THE ESA/SCC SYSTEM USERS (Continued)
• If any data to be reviewed is incomplete, inaccurate, or results in rejection of the data. • Once components have been delivered by the component manufacturer to the orderer, the ESA/SCC Non-Conformance System, as defined within ESA/SCC 22800, shall continue to be applied. Component Engineering Training Course

FLOW DIAGRAM OF NON-CONFORMANCE PROCEDURE
1 2 LEVEL DETERMINATION Telex Notification to ESA / SCC Lot Rejection LOCAL MRB Decision ESA / SCC MRB Decision: • Reject from Lot • Rework • Use”as is” (waiver) ESA / SCC Documentation Affected Initiate D.C.R. nn Corrective Action D.C.R. decision by SCCG NO Distribution Distribution YES Corrective Actions Reject NC Closed NCR Closed Review of Qualification Status by SCCG File in Qualification Report ESA / SCC QPL Component Engineering Training Course

NON-CONFORMANCE PROCEDURES
All non-conformances are notified to a Materials Review Board, by means of a Non-Conformance Control Sheet. The Non-Conformance Control Sheet initially details the details of the non-conformance and, later, analysis of the failure, the MRB decision and confirmation that all necessary actions have been carried to their conclusion. Component Engineering Training Course

Component Engineering Training Course

NON-CONFORMANCE LEVELS
There are two levels of Non-Conformance: LEVEL 1: MINOR - Any departure from the requirements which can be corrected and will not contravene ESA/SCC documentation. MINOR Non-Conformances result in Local Material Review Boards (MRB). LEVEL 2: MAJOR - All other Non-Conformances. MAJOR Non-Conformances result in ESA/SCC Material Review Boards (MRB). Component Engineering Training Course

LOCAL MRB Local MRB shall be composed, as a minimum, of the following persons:- • Chief Inspector of the manufacturer (Chairman) • National Space Agency representative • Responsible engineer of the manufacturer • Representative of the Orderer (in the case of procurement) Members of the MRB may call in specialists as required, but they shall not have voting rights. Component Engineering Training Course

LOCAL MRB (CONT.) In determining the disposition and corrective action to be taken, the board shall: • Take all necessary action to investigate the causes of the non-conformance. • Review the records of previous actions applicable to similar or identical cases. • Consider the recommendations of specialists acting in an advisory capacity. • Initiate failure analysis of failed items, if appropriate. • Consider and record the effects of the non- conformance on contractual requirements. Component Engineering Training Course

ESA/SCC MRB The ESA/SCC MRB shall be composed, as a minimum, of the following persons:- • National Space Agency representative (Chairman) • Chief Inspector of the manufacturer • Qualification Manager of the manufacturer • ESA/SCC Representative having acceptance authority • Representative of the Orderer (if applicable) Members of the ESA/SCC MRB may call in specialists as required, but these shall have no voting rights. Component Engineering Training Course

NCCS RESOLUTION (CONT.)
ACTIONS • Disposition for corrective action, • Disposition of the actual product that is the subject of the non-conformance (e.g. whether or not it can be of further use), • Any preventive measures taken. Decisions of the MRB must be unanimous. Component Engineering Training Course

NCCS CLOSE-OUT The last two lines on the NCCS allow for the confirmation and verification of the implementation of the MRB disposition. The NSA Inspector and the Chief Inspector shall ensure, through actual inspection, that all actions are completed. Close-out requires that, as a minimum:- • Corrective actions have been accomplished. • The effectiveness of preventive actions has been proven. • The necessary design or documentation changes have been accomplished and verified by tests if so decided by the MRB. • Preventive actions have been taken also in respect of identical material. • The NCCS is signed off by the Chief Inspector and the NSA Inspector to evidence the technical review and completion of all actions decided upon by the MRB. Component Engineering Training Course

NON-CONFORMANCE CONTROL SHEET DISTRIBUTION
Copies are to be sent members of the relevant MRB immediately the “Identification” and “Description” sections have been completed by the Chief Inspector. In urgent cases, a fax or is recommended. After close-out by the MRB the NSA Inspector is responsible for defining the distribution list and for its distribution. Component Engineering Training Course

DISTRIBUTION OF NON-CONFORMANCE CONTROL SHEET (CONT.)
For both non-conformance levels, the standard distribution list shall include as a minimum:- • The Chief Inspector of the Manufacturer. • The Qualification Manager of the manufacturer. • The National Space Agency representative concerned. • ESA/SCC (level 1, for information only). • The National Space Agency concerned for incorporation in the qualification report (but only after “close-out”). • the Orderer (in case of procurement). • other persons concerned. Component Engineering Training Course

SPUR’S NON CONFORMANCE REPORT

NCR – SPUR’S APPROACH 1) The NCR is raised as soon as the non conformance is discovered with all the necessary details including which part of the procurement specification the non conformity applies to. 2) The report is then sent to the customer and negotiation between customer and supplier is entered into. An MRB is called if it is considered necessary. 3)The NCR is closed out once a decision is reached to whether they are to accept the components. For the component supplier it is important that all NCRs are assigned unique numbers and kept in a log along with any written agreements between the supplier and the customer. Copies of the NCRs must then accompany the components to the customer. Component Engineering Training Course

ESA ALERT SYSTEM The ESA Alert system was launched in December 1995.
This system is aimed at providing awareness of failures and problems experienced in space projects, in order to eliminate or minimise their impacts and prevent their recurrence in current and future projects.. The ESA Alert System and its implementation procedure is fully described within Q/EAS/PROC/1 Details of how to receive ESA Alerts can also be found via the ESCIES website ( or go directly to: Component Engineering Training Course

ESA ALERT SYSTEM Component Engineering Training Course

COMPONENT RELIFE TESTING

COMPONENT RELIFING If a EEE component has exceeded its shelf life a relifing procedure can be used validate an extension to life. Relifeing Procedure: A set of tests performed in order to verify that the initial quality and reliability levels have not been affected by time. Relifing is not usually systematically applied to shelf life components when they reach expiry date. It is initiated whenever an intended supply arises from a batch in question at a post expiry date. Component Engineering Training Course

RELIFING (Cont.) The shelf life and the time that a EEE component can be used after relifing is detailed in a number of ‘Relifing Rules’ published by a number of organisations in the space industry such as: ESA – PSS 01 60 Astrium – CDSP-FD012-PRE CNES – QFT-IN-0110MM None of these documents are backed up their figures and rules with consistent approach and physics. Astrium under contract from CNES and ESA have updated the ESA rules taking into account field-return and failure mechanism analysis and have established a new storage and de-storage procedure that is to be included in ECSS format. Component Engineering Training Course

RELIFING (Cont.) The number of samples required for relifing is usually defined in the specification and in is usually 100% or by AQL sample according to test and component type. Specifications and methods used during relifing should be the same as those implemented at the initial procurement, except the most recent update issues should be applied. Required test vary from between specifications and component type but typically they might be: Electrical Parameters External Visual Inspection Solderability Hermeticity Component Engineering Training Course

TYPICAL TIME PERIOD DEFINITIONS
SAVERS 10 YEARS 3 4 MONTHS CONNECTORS & ACCESSORIES 6 4 ALL OTHER COMPONENTS 9 Component Engineering Training Course

ASTRIUM STUDY I The CNES study consisted of two elements:
Analysing >4000 batches of relifing data from Astrium. 96% of the lots exhibited no problems. Vast majority of failures were visual discrepancies such as corrosion on leads. No defects resulted from a clear failure mechanism induced by storage. A small percentage of defects remained due to random defects implying that it is still necessary to screen at the relife of parts. Component Engineering Training Course

ASTRIUM STUDY II Batches of stored devices were subjected to life 3000hr life test in order to understand some potential effects of long term storage (10 years) on reliability. Part types tested: Resistors: Metal Film and Power Wire-wound Capacitors: Ceramic and Solid Tantalum Transistors: Signal and Power Bipolar Diodes: Zener IC: IREG and OP AMP Relays: Non-Latching Inductors None of these parts exhibited any clear reliability concern. Component Engineering Training Course

RESULTS OF THE ASTRIUM STUDY
Astrium findings are summarised as follows: 1) No reliability issue is to be feared on relifed parts when proper storage conditions are in place. No clear effect of storage duration was found on a relifed test yield. 2) Recommendation to allow a longer period of time before it becomes necessary to relife. This period of time is a function of the device type and storage class. 3) Relifeing tests are considered necessary to sort out the low percentage of potentially weak parts. Component Engineering Training Course

ASTRIUM CONCLUSION An extended period of storage is now allowed. This will give users a better economical output keeping all reliability guarantees for these parts. Component Engineering Training Course

NEW SPECIFICATION Two classes of storage defined: Class A and Class B
Class B: Based on a controlled atmosphere Class A: Based on neutral ambience or dry air Component Engineering Training Course

NEW SPECIFICATION – ENVIRONMENTAL REQUIREMENTS

NEW SPECIFICATION:TIME PARAMETERS-DEFINITION AND VALUES
T0: Original date code T1: Maximum allowed period with no relifing control ΔT: Maximum allowed storage period after relifing control N: Maximum number of relifing authorised T2: Absolute maximum storage duration N= N=2 N=… T0→→→→T1→→ΔT→→ ΔT…→ T0→→→→→→→→→→→→→→T2 Not all relife steps are necessary. A user can decide to only relife his parts just before they are used i.e. before T2 is elapsed. Component Engineering Training Course

TIME PARAMETERS vs. CATEGORIES.
N T2 Category 1 9 years 3 years 2 15 years Category 2 6 Years 3 Category 3 Case by Case Case by Case and <15 years CAT1: Generally for class A storage CAT2: Generally for class B storage CAT3: Case by Case Component Engineering Training Course

EXTRACT FROM ASTRIUM SPECIFICATION

ELECTROSTATIC DISCHARGE (ESD)

ELECTROSTATIC DISCHARGE (ESD)
ESD is a major cause of premature failure in electronic components Together with Electrical Overstress (EOS) it can account for over 50% of all field failures ESD is totally preventable if proper precautions are taken Component Engineering Training Course

WHAT IS ESD ? Charge is stored in insulators and is dissipated upon contact with a conductor. Static charge build up in a typical working environment can generate potentials ranging from 100V to 20 kV build up . If this is then discharged through a semiconductor the burst of charge can cause serious damage and cause the device to fail. Components can be damaged by contact with a charged body of by exposure to a high electric field Component Engineering Training Course

ELECTRICAL FIELD SURROUNDING A STATICALLY CHARGED PERSON

ESD PROTECTIVE MEASURES
Handling and storage at RH between 45% and 55% Grounding of devices, equipment and tools Avoid of insulating materials that are subject to charge accumulation (particularly plastics) Conducting work surfaces, floors and storage cabinets Use of containers and packing materials with ESD protection Grounding of personnel by wrist and/or heal straps Nylon coats must not be worn. Untreated cotton is preferred. Component Engineering Training Course

TYPICAL ELECTROSTATIC VOLTAGES
Means of Static Generation Electrostatic Voltages 10% to 20% Relative Humidity % to 90% Relative Humidity Worker at bench 6,000 100 Vinyl envelopes for work instructions 7,000 600 Walking over Vinyl floor 12,000 250 Work chair padded with polyurethane foam 18,000 1,500 Common poly bag picked up from bench 20,000 1,200 Walking across Carpet 35,000 Component Engineering Training Course

TYPICAL CHARGE SOURCES
Object or Process Material or Activity Work Surfaces Waxed, painted or varnished surfaces Common vinyl or plastics Floors Sealed concrete Waxed, finished wood Common vinyl tiles or sheeting Clothes Common clean room smocks Common synthetic personal garments Non-conductive shoes Virgin cotton Chairs Finished wood Vinyl Fibreglass Packaging and Handling Common plastic - bags, wraps, envelopes Common bubble pack, foam Common plastic trays, plastic tote boxes, vials, parts bins Assembly, Cleaning, Test and Repair Areas Spray cleaners Common plastic solder suckers Solder irons with ungrounded tips Solvent brushes (synthetic bristles) Cleaning or drying by fluid or evaporation Temperature chambers Cryogenic sprays Heat guns and blowers Sand-blasting Electrostatic copiers Component Engineering Training Course

THE EFFECTS OF ESD Component Engineering Training Course

FAILURE ANALYSIS Component Engineering Training Course

FAILURE ANALYSIS Background research
Avoid additional stresses when removing the component Observe proper handling Never de-lid a component until all external tests are completed. De-lid with extreme care and with the most appropriate method. Do not jump to conclusions Report findings as soon as the analysis is complete Give serious consideration to the conclusions and recommendations Component Engineering Training Course

EXAMPLE OF A FAILURE ANALYSIS – CHIP RESISTORS

EXAMPLE FAILURE ANALYSIS

EXAMPLE FAILURE ANALYSIS – RADIOGRAPHIC INSPECTION

EXAMPLE FAILURE ANALYSIS

CONCLUSION The internal close-up inspection of the failing devices showed that the metallisation near the termination has become thin to the point of electrical open circuit. The most likely cause of this would appear to be Electrical Over Stress. The point of break down occurs in the weakest area of the network of tracks, which is where current density would be at a maximum during operating conditions. A similar inspection of the good parts shows no visible signs of defect in this (or any other) area. Component Engineering Training Course

INTERMETALLICS Component Engineering Training Course

TIN WHISKERS Component Engineering Training Course

WARNING! Due to legislative pressures in recent years, the electronics industry is being pushed into eliminating lead from their products and manufacturing processes. This has resulted in many manufacturers moving towards pure tin electroplates. But… PURE TIN ELECTROPLATES CAN CAUSE POTENTIALLY DAMAGING GROWTHS KNOWN AS TIN WHISKERS. Component Engineering Training Course

Length: Up to 10mm (typically <1mm)
WHAT ARE TIN WHISKERS? ‘Hair-like’ single crystal structures that may grow from tin finished surfaces. Length: Up to 10mm (typically <1mm) Diameter: from 6nm to 10μm (typically ~ 1μm) Growth from the base not the tip Whisker extrusion is driven by mechanical stress relief and diffusion processes in the tin finish. Component Engineering Training Course

EXAMPLES OF WHISKER GROWTH

SURFACE MOUNT CAPACITOR

TIN WHISKERS Component Engineering Training Course

A POSSIBLE MECHANISM FOR WHISKER GROWTH
1. Substrate elements (Cu, Zn, etc.) diffuse into tin along grain boundaries 2. Intermetallic compounds (IMC) may form preferentially in the grain boundaries 3. As a result stress builds up in the tin layer. 4. To relieve stress, whiskers extrude through ruptures in the tin oxide. Component Engineering Training Course

WHY SHOULD YOU BE CONCERNED ABOUT WHISKERS?
Electrical Short Circuits - Permanent (if current < 10s of mA) - Intermittent (if current > 10s of mA) Metal Vapour Arc in Vacuum - Atmospheric pressure < ~150 torr, V> ~18V and I>10s of Amps, then whisker can vapourize into highly conductive plasma of tin ions. - Plasma can form arcs capable of carrying HUNDREDS OF AMPS - Arc is sustained by tin evaporated from the surrounding area Debris/Contamination - Interfere with sensitive optics - Cause shorts in areas remote from whisker origins Component Engineering Training Course

AVOID PURE TIN IF POSSIBLE
WHAT CAN BE DONE? Reduction of Stress Hot oil reflow / hot solder dip (preferably Sn/Pb solder) High temperature anneal substrate and tin finish Underplate with diffusion resistant barrier may delay onset. Use of Physical Barriers to Insulate against Potential Shorts Conformal coat or other insulating barriers Increased spacing of surfaces of opposite polarity > 0.5 inches AVOID PURE TIN IF POSSIBLE Component Engineering Training Course

SOME LIMITATIONS – HOT SOLDER DIP
Hot Solder Dip does not always allow complete coverage of terminals to the component body. There is a risk of heat damage to the component package and the seals. Component Engineering Training Course

SOME LIMITATIONS - CONFORMAL COATING
Conformal coating reduces (but does not eliminate) rate of whisker growth compared to an uncoated specimen. Whiskers have grown through 0.25 mil (6μm) Uralane 5750 coating. Component Engineering Training Course

For Further Information…
NASA’s Goddard Space Flight Centre runs the ‘Tin Whisker Home Page’: Component Engineering Training Course

Component Engineering Training Course

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