Presentation on theme: "EML 4561 Introduction to Electronic Packaging W. Kinzy Jones, Professor MME MWF 11:00-11:50 305-393-0506(mobile) 305-348-4663 (office )"— Presentation transcript:
EML 4561 Introduction to Electronic Packaging W. Kinzy Jones, Professor MME MWF 11:00-11:50 Jones@fiu.edu 305-393-0506(mobile) 305-348-4663 (office )
Notes on the field I am Past President and Fellow, IMAPS, The Microelectronics and Packaging Society Research in advanced packaging, 1 st Level Assembly, Thermal Management, Components and Electronic Materials- Funded over $7MM in past 15 years Electronic packaging is a application field that crosses over many disciplines. There are 80,000 ME working in the field. Conferences/journals by ASME, IEEE, ASM, IMAPS, etc. All former graduate student hired prior to graduation!
19751995 2015 Year 1 10 100 1000 10000 WW S/C Revenue ($B) Trend to Convergent Systems Businesses Businesses Host-based computing Host-based computing Mainframe Mainframe Dumb terminal Dumb terminal Few vendors / architecture Few vendors / architecture Mainframes Transistors / chip 1B 1M 10M 100M 10B 100K 10K 1K 100B PCs PCs / Servers Businesses & some people Businesses & some people Client-server computing Client-server computing Local area connection Local area connection Text/graphical interface Text/graphical interface Many vendors / few architectures Many vendors / few architectures Today All businesses, people, objects All businesses, people, objects Network computing Network computing Wide area / bandwidth Wide area / bandwidth Graphical, voice, multimedia, etc. Graphical, voice, multimedia, etc. Many vendors / platforms Many vendors / platforms Internet Source: Russ Lange, IBM Microelectronics WirelessWireless WiredWired Convergent Systems
What are Convergent Microminiaturized Microsystems (CMM)? Convergent: Two or more functions Microminiaturized: >1000x volume reductions Microsystems: systems with micro-scale technologies
Trend to Convergent Microminiaturized Systems (CMM) Functional –Data and Voice Technology –Digital, RF, Analog and Optical Product – Computer, consumer and telecom Video Cell Phone CONSUMER ELECTRONICS Medical Implant/ Diagnostic Monitor/ Communicator MEDICAL
SOC Challenges Major Delay Problems Summary Fundamental Digital Limits Integration RF Limits Fundamental Design & Verification Complexity Test Complexity Process Complexity Mixed Function Costs Wafer Fab Costs Legal Problems Time-to-market
SOC: Integration of Two or More Mixed Functions in a Single IC (a)(b)
Bulky Size What is Wrong with Current Packaging for Tomorrows Needs? Higher Cost Poorer Reliability Active ICs 10% Passives: 90% IC: PPB Systems Pkg: PPM Cellular Phone Weight Trend Barrier to all future systems Lower Performance
What is SOP, SIP, or Board? A.) Todays Board: Interconnect Components RF ICDigital IC Substrate Optical IC IC B.) SIP: Stacked Chip/Package for Reduced Form Factors Flash RAM P IC Package Super IC Stack (ASET) Package (Fujitsu) Stacked IC (Amkor) C.) SOP: Optimizes Functions Between ICs and Package RF ICOpto ICDigital IC Package with Opto, RF, Digital Functions RFOpto Electrical 3-D ICs
What are SOC, SIP, and SOP? SOC: System on Chip –Highly integrated and mixed signal IC with partial system functions in one component SIP: System in Package –3-D IC or Package Assembly –Requires Systems Board SOP: System on Package –Microminiaturized system-level board with two or more embedded RF, digital, analog and optical functions –Best of on-chip and package integration for cost, performance, size and reliability –Similar to SOC but total system function in a microminiaturized board
SOP: SIP + SOC+Systems Board 3 -D Stacking of ICS or Package Structures, Similar to PWB –Macro dimensions –Vertical stack up –Testable 3 -D Build up, similar to IC Fabrication –Micro to Nano dimensions –Sequential build up and test similar to MCM-D and IC –Wafer to IC concept for high yield SIPSOP MEMS Ga-As SIP SOC MEMS SIP Ga-As
Why SOP? SOC is complex to design and test, expensive to Fabricate, long time-to-market and presents fundamental limits. IC companys dream for decades. No complete system has been shipped to date. SOP optimizes the best of IC and package integration for cost, performance, size and reliability. Faster turn-around and faster time-to-market. Provides full system solution today that SOC provides tomorrow. SIP is a 3-D IC or package, not a complete system
Industrial & Medical 11% $105B Military 9% $ 8.7B Automotive 5% $ 48B Business Equip 38% $ 383B Communications 26% $ 259B Consumer 26% $112B Information Technology is a Trillion $ Industry Microsystems & Packaging is 25% of IT Source: Prismark
MSP Market ($320 B) Microelectronics ($165B) Systems Packaging ($125B) Opto & MEMS ($30B)
Information Technology and Microsystem Markets Billion $/Year
Core Technologies Substrates, circuit boards Interconnect Passive components Active components Packaging Traditionally these were treated as discrete elements Advanced applications require integrated approach of System Level Packaging
Substrates and Circuit Boards Printed Circuit Board (PCB), Printed Wiring Board (PWB) –Epoxy-glass composite, copper –FR-4, FR = fire retardant –Advanced Resins Polyimide BT = bismaleimide traizine CE = cyanate ester Ceramic substrates –Aluminum oxide, aluminum nitride, beryllium oxide, glass-ceramic –Interconnect metals - W, Mo, Au, Cu, Ag Multichip Modules –MCM-D,C,L Platform –Support interconnect and components –Thermal path away from ICs –Withstand mechanical stresses and vibrations
Solder Primary functions –Electrical connection between component and interconnect –Mechanical attachment of component to board –Thermal path from component to board Alloys of various compositions and melting points Lead-Tin solder most common –Eutectic composition: 63% Tin, 47% Lead –60/40 or 2% silver added Solder paste for screen printing, pressure dispensing –Alloy particles –Flux and activator chemicals –Vehicle to control viscosity Wave soldering –Foam or spray flux –Preheat board –Turbulent wave to spread solder –Laminar wave to smooth
Effect of Underfill on Temp Cycling Performance With filler, 27ppm
Packaging Considerations that Effect the Electrical Performance
Interconnects Worsen: Signal Integrity Performance: switching, speed Reliability Form, fit, and function- weight, volume, power
Interconnects Can Have Very Important Electrical Properties Property Self-inductance Capacitance to ground transmission line Mutual Inductance, capacitance Resistance, loss Possible Impact Ground bounce Delay, power sag Propagation delay, reflection Cross-talk, noise Damping, ringing, power sag
Drivers for Reduction of Interconnect Length Directly reduces inductance, capacitance, resistance and delay Indirectly reduces switching time, power, size, ringing, ground bounce, and power sag
Electrical Fundamentals Resistance ( ohms). Relates Ohms law relationship between current and voltage, V=IR. Resistivity,, is a materials property, in ohm-meters. Resistance, R = Length x / cross-sectional area of conductor Capacitance (farads) relates to the ability to store charge. Capacitance for a parallel plate capacitor is proportional to the dielectric constant,K, times the area of the plate/ thickness of dielectric. Inductance ( henry)- relates to the voltage generated to oppose a change in current
Basic Resistance Equation Resistance R = L / A = L /wt = L/w R s where R s is defined as the sheet resistivity, is resistivity, L is the length and A is the cross sectional area of the conductor/resistor A square ( L=W ) for a fixed thickness of material has a fixed resistance per square, independent of size. A square anything
Capacitance is In the insulation between more than one conductor Orders of Magnitude higher outside the chip than inside The dominate determinant of digital speed
Capacitance of Electrically Short Interconnections Capacitance is the sum of all output capacitance of all drivers to that interconnect, the input capacitance of all receivers, and the distributed capacitance to ground of the interconnection
Switching Time, Power If a step voltage is applied to an RC network, the time delay is proportional to RC. If the capacitor is charged from zero to full charge, the energy dissipated, W, is independent of R and equals CV 2 /2. But energy is also power X time delay. If we operate twice as fast, the circuit will dissipate twice the power.
Inductance Opposes a change in current by generating a back voltage. If the current change is positive, the back voltage subtracts from the voltage applied, causing a power sag. The voltage is equal to the inductance times the rate of change of the current, V L = L di/dt Self inductance exists in every wire, trace, wire bond, solder joint, etc..It is minimized by large, short conductors, or a sheet conductor as a ground or power plane. Example: If we switch 1 amp in 5 nsec on a 1 trace with 7.8 nH, we generate a back voltage of 1.6 volts.
Crosstalk There is a mutual capacitance between two adjacent insulated conductors that couples a fraction of one voltage to the other There is also mutual inductance, functioning as a transformer by generating a voltage in each when the current changes in the other. This is crosstalk. Can be minimized by design (keep talkers and listeners apart) and use of ground/power traces between talkers/listeners
Ground Bounce, Power Sag Cause: Common-mode impedance, usually inductive Digital devices require most of their power supply current during switching. Clocked signals switch together, so there could be a large total surge The inductance in the power and ground leads causes ground bounce and power sag.
Bypass ( decoupling) Capacitors To reduce power sag and ground bounce, add decoupling capacitors. Value should be 20-100 nF/sq.cm of silicon. Decoupling capacitors should have low parasitic inductance. Capacitors serve as local energy reserves and need to be close to the power/ground leads
RLC Circuit Switching The voltage step sent down an interconnect can be distorted badly by the R, C, and L on the interconnect This distortion can be removed by the right balance of the values of R,L and C. When R = 2* sqrt(L/C), critical damping occurs If R is above critical damping, switching slows down; if below, ringing of the signal occurs
Transmission Lines Any interconnect whose length is over a small fraction of the wavelength of the signal it carries acts like both a transmission line and an antenna radiating or receiving noise As speed increase, the lumped analysis of L,R,and C components must be replaced by the distributed network of L,R, and C. Property shielded interconnects minimize the effect of antenna properties, but the transmission properties remain
Transmission Line Properties A transmission line appears as a string of small inductors and capacitors, with seven principal properties: length L, inductance per unit length, capacitance per unit length, impedance (Z), attenuation, propagation velocity, and time delay
Transmission line traces Matched impedance systems require containment of the electrical fields. This has lead to designs including the stripline, the microstrip, the buried microstrip. Additionally, for multilayer routing, vias must be considered Stripline microstrip
Traveling Waves on an Infinite Line Switching on a DC source voltage, V, : –draws the same current as a resistor of value Z o connected to V. –current flows down the line at the propagation velocity, while the current progressively charges up the line capacitance to voltage V. Hence a voltage step V also travels down the line. –Draws current indefinitely due to an infinitely long line –The source only sees a resistive load Z o continuously drawing current
Traveling Waves on an Unterminated Line When the line is unterminated ( R is infinite): –Kirchoffs current law still applies at the far end: the sum of current entering the end must equal the current leaving the end. But there is no load to draw current from the end node. –Therefore, an equal reflected current wave is generated that travels back toward the source. –This reflected current wave requires an extra voltage source, V, to propel it, so the voltage at the far end steps up to 2V. –This increased voltage travels back towards the source along with the reflected current. –What happens at the source depends on the sources internal impedance –The waves can on occasion reflected back and forth several times
Lines Traveling Waves Capacitively Terminated The problem of reflection is compounded by capacitance at the ends. When a transmission line drives a capacitor, the extra capacitance causes: –reflections, since the line is now mismatched –ringing for some drivers, since there is no longer critical damping CMOS inputs are essentially capacitive.
AC Termination To minimize power dissipation, a series capacitor,C, can be added to the terminating resistor This terminated the line only when a voltage transition occurs and allows no DC power dissipation in R The value of C must be selected carefully, either by simulation or experimentation to minimize the effect of capacitively terminated lines.
When Interconnections are Electrically Significant When interconnects degrade switching time When the signals are not correctly damped When large amounts of current switch In the time domain, when the line propagation delay approaches the driver switching time. Propagation delay is proportional to length In the frequency domain, when the wavelength of the signal ( including harmonics) are not long compared to the length of the interconnect ( for 100 Mhz- over a few centimeters)
Packaging What packaging provides : Interconnection Power Distribution Thermal Management Environmental Protection What the package is made from-- materials, parts What is used to design and fabricate packages: Facilities and Equipment Manufacturing and Design Tools Process by which the package is produced over time
Technology Drives Increases in semiconductor complexity from decreased feature size Corresponding increases in systems speed Increase in input/output (I/O) density Increase in power density (W/cm 2 )
Levels of Packaging 1st Level Connection –IC to Common Circuit Base –Wirebonds or solder bumps to package base 2nd Level Connection –Common Circuit Base to Circuit Board –Package leads soldered to PCB 3rd Level Connection –Assembly of multiple boards into larger assembly –Video card, modem, game port on a PC motherboard 4th and 5th Level Connections –System level assembly with several 3rd Level subassemblies –Motion control, visual alignment, user interface, etc. in manufacturing equipment