Presentation on theme: "“Impact of Low-Voltage Devices on Test and Inspection”"— Presentation transcript:
1 “Impact of Low-Voltage Devices on Test and Inspection” Teradyne Assembly Test Division Website:Michael J Smith
2 What’s Driving the Use of Low Voltage Devices? Cramming more components onto integrated circuits-“With unit cost falling as the number of components per circuit rises, by 1975 economics may dictate squeezing as many as 65,000 components on a single silicon chip.”Gordon E. Moore April 19th 1965
3 What’s Driving the Use of Low Voltage Devices? Increasing functionalitySpeedMemoryColourExtended operationSmall sizeDisk drivesLarger size42-inch displays
6 What’s Driving the Use of Low Voltage Devices? Environmental concernsReduce power consumptionPd = F x C x V²Restrict heat generation.Reduce air-conditioningLess temperature differentiation
7 What’s Driving the Use of Low Voltage Devices? New functionsWireless communication.3G, WiFi, BluetoothCombining functionsCell phonePDA,CamerasGPSVideo
8 What’s Driving the Use of Low Voltage Devices? The future?MP3 JukeboxPortable Mpeg4 video playersNanotechnologyRemote vehicles
9 What’s Driving the Use of Low Voltage Devices? The future?Personal serverTele-healthSecurity
10 Azalia Audio Architecture Hyper-Threading Technology The Next Generation Technology Challenge: Intel’s 2004 Desktop Platform VisionGMCH1 PATA portNext GenerationInt. Gfx corePCI Express* x16Discrete GraphicsAzalia Audio Architecture800MHz FSB4 Serial ATA portsRAID0/1AHCI1Hyper-Threading Technology8 Hi-Speed USB 2.0 Ports4 PCI Express* x1 lanesPCI PortsPlatform SoftwareDual ChannelDDR2-533MCHICHHigher integration - Smaller gate geometries - Lower voltages
11 The Next Generation Technology Challenge: Intel’s 2004 Desktop Platform Vision DDR SDRAM @ 2.5 VFront Side Bus @ 1.2 VRambus 64Bit @ 1.8 VHUB Interface @ 1.5 VAGP @ 1.5 VSource : Intel Corp.
12 Voltage Level Technology Trends 10/ V JEDEC 8-502/ V JEDEC 8-710/ V JEDEC 8-1105/ V JEDEC 8-1212/ V JEDEC 8-14Joint Electron Device Engineering CouncilSource : Texas Instrument Technology Roadmap
13 The 1980-90’s Logic Family 5.0V Output Voltage (V) 3.3V High 2.4V 0.8V 4.54.03.53.02.52.01.51.00.55.0V3.3VOutput Voltage (V)High2.4V0.8VLowLogic Level
14 2.5 Volt Logic - JEDEC 8-5 5.0V Output Voltage (V) 3.3V High 1.7V 0.7V 4.54.03.53.02.52.01.51.00.55.0V3.3VOutput Voltage (V)High1.7V0.7VLowLogic LevelJoint Electron Device Engineering Council
15 1.8 Volt Logic - JEDEC 8-7 5.0V Output Voltage (V) 3.3V High 0.65V 4.54.03.53.02.52.01.51.00.55.0V3.3VOutput Voltage (V)High0.65V0.35VLowLogic LevelJoint Electron Device Engineering Council
16 1.5 Volt Logic - JEDEC 8-11 5.0V Output Voltage (V) 3.3V High 0.65V 4.54.03.53.02.52.01.51.00.55.0V3.3VOutput Voltage (V)High0.65V0.35VLowLogic LevelJoint Electron Device Engineering Council
17 1.0 Volt Logic - JEDEC 8-14 5.0V Output Voltage (V) 3.3V High 0.65V 4.54.03.53.02.52.01.51.00.55.0V3.3VOutput Voltage (V)High0.65V0.35VLowLogic LevelJoint Electron Device Engineering Council
18 1.0 Volt Logic - JEDEC 8-14 5.0V Maximum High = 200mV above VDD 4.54.03.53.02.52.01.51.00.55.0VMaximum High = 200mV above VDDMaximum Low = -200mV below GND3.3VOutput Voltage (V)Maximum High0.65V0.35VMinimum LowLogic LevelJoint Electron Device Engineering Council
19 What Are the Issues? V - Voltage: I - Current: 1.0 Volt Logic 200mV below GND and 200mV above VDD JEDEC1.5 & 1.8 Volt Logic300mV below GND and 300mV above VDD JEDECIntel AGTL signal350mV for Intel AGTL signal for only 10nS500mV for 15pSI - Current:90nm technologyNo more than 100mA through each outputJoint Electron Device Engineering Council
20 Outside the Safe Operating Area? Over-Voltage and Over-Current FailureThese failures taken place in milliseconds - once the second breakdown region has been reached, the transistor will enter a negative resistance state, and there is nothing that will prevent total failure.A close-up view (right) with greater damage. A large section of the die has exploded from the failure point outwards, and molten silicon has been sprayed all over the die. This failure would almost certainly indicate a short on all terminals (provided bonding wires are intact).ON Semiconductor
21 Newer Parts Are More Sensitive to Over-Voltage Conditions As core and I/O Voltages decrease, so must the transistor gate oxide thicknessThinner oxides break down at lower voltagesGraph is for a 100ppm failure rate
22 90nm Generation Gate Oxide Leakage through the silicon dioxide layer of a gate increases exponentially as its thickness decreases. Nevertheless, making the dielectric ever thinner is necessary in order to meet increasing performance goals.When the gate dielectric of a transistor thins, its insular quality decreases and current leaks through it.Uncontrolled, this conduction causes the transistor to stray from its purely "on" and "off" state and into an "on" and "leaky off" behavior. The effect is similar to that of a light bulb that lights fully when turned on but only dims when you turn the light switch off.1.2nmThickGate Oxide is less than 5 atomic layers
23 Newer Parts Are More Sensitive to Over-Voltage Conditions (SOA) Today’s processors have strict over-voltage/time specificationAGTL signals should not exceed 1.8V, always for < 10nsecSource : Intel Corp. Itanium 2 processor datasheet
24 Over-Current-Related Failures (Joule heating)Bondwire fusing or bambooingDie metallization failure
25 Over-Voltage-Related Failures CMOS latch-upA self sustaining short from VDD to GND
26 Over-Voltage-Related Failures Gate oxide breakdown, time dependent dielectric breakdown (TDDB)Time Dependent Breakdown of Ultrathin Gate OxideBy Abdullah M. Yassine, Member, IEEE, H. E. Nariman, Member, IEEE, Michael McBride, Mirac Uzer, Member, IEEE,and Kola R. Olasupo, Member, IEEE
27 Over-Voltage-Related Failures Electrostatic Discharge (ESD) damageDamaged Protection diodeThis transistor was also confirmed failed by ESD. You can see where the discharge energy surge has buried through the weakest point(s) in the oxide layer through to the silicon. Bipolar devices are becoming very small and susceptible to ESD.Photos Rohm Electronics
28 What does this mean for Electrical Test In-circuitTight control of voltage and currentMinimize NoiseFixture, Feedback etcFunctional TestBoundary Scan and BISTGround Bounce
29 The Difficulty of Programming the Correct Voltage Levels Simple Voltage DividerMaximum Output drive current of 100mA at 0.6 VoltagesR = V/I ~ 6 OhmsOlder Driver Output Impedance~ 5 OhmsConnection ResistanceWireRelaysContact~ 1 Ohm5 Ohms Output Impedance+1 Ohm wiring, relay and contact resistance0.6VEquivalent Output Resistance6 Ohms1.2VDriver0.6V
30 The Difficulty of Programming the Correct Voltage Levels 710mVUnderLoadActual example of a non custom design driver sensor
31 The Difficulty of Programming the Correct Voltage Levels DUT1.2V LogicBackdriven Part1.2V LogicHighLow20mA0.98V0.62V5 Ohm1 OhmVprog = 1.2V(+/- 100mV)20mVDriver100mV80mA5 Ohm1 OhmVprog = 1.2V(+/- 100mV)80mVDriver400mV
32 The Difficulty of Programming the Correct Voltage Levels DUT1.2V LogicBackdriven Part1.2V LogicHighLow20mA1.68V1.12V5 Ohm1 OhmVprog = 1.7V(+/- 100mV)20mVDriver100mV80mA5 Ohm1 OhmVprog = 1.7V(+/- 100mV)80mVDriver400mV
33 The Difficulty of Programming the Correct Voltage Levels For 4 logic families you may need 8 sensor levels to measure both inputs and outputs voltages1.0V1.2V1.4V1.2VHigh impedance in-circuit drivers, require different programmed outputs to match the device output currents.1.7V1.5V1.5V1.9V1.8V1.8VBackdriven currents could range from 80mA’s to 500mA’s2.2V
34 The Difficulty of Programming the Correct Voltage Levels DUTDUT1.2V LogicBackdriven Part1.2V LogicHighLow20mA0.98V5 Ohm1 OhmVprog = 1.2V(+/- 100mV)20mVDriver100mV20mA5 Ohm1 OhmVprog = 1.2V(+/- 100mV)20mVDriver100mV
35 The Difficulty of Programming the Correct Voltage Levels DUTDUT1.2V LogicBackdriven Part1.2V LogicHighLow20mA0.62V5 Ohm1 OhmVprog = 1.2V(+/- 100mV)20mVDriver100mV80mA5 Ohm1 OhmVprog = 1.2V(+/- 100mV)80mVDriver400mV
36 Spikes Are Caused By Changing States V = L x ItDUTBackdriven PartIsolation,Force a Logic highStimulusMeasurementUncontrolled Voltage Spikes result from outputs changing while they are being backdrivenExample:When back driving a low to a high and the back driven output changes, the out signal now re-enforces the back drive level and the current has to go from a positive current to zero.
37 Spikes Are Caused By Changing States Example:Greater than 9V Voltage Spike Measured!Can cause CMOS latch-up failures or TDDB
38 Tri-stated or Back-driven? With complex devices can we really be sure that our big devices are tri-state?Tri-state back-drive <10mAOutput back-drive >80mALimits of 100mA?
39 Tri-stated or Back-driven? An analysis of a typical in-circuit test program of a PC motherboard found that back-driving occurred during 30% of the digital device tests.A total of 156 back-driving events requiring greater than 50mA of back-driving current were recorded.Median back-drive current176mA.Highest back-drive current600mA.Longest back-drive duration2.5mS.
40 Functional Test Functional Test Boundary Scan and BIST Tight control of voltage and currentLow impedance and feedbackMinimize NoiseFixture designBoundary Scan and BISTExternal circuits will need to match logic familiesFixture and interface designGround Bounce
41 Potential Impact Damaged or Stressed Components Reduced Fault Coverage Catastrophic or latent failures related toGate Oxide BreakdownESD Diode overstressCMOS Latch-upReduced Fault CoverageUnable to test components without violating device specificationsIncreased False FailuresNeedless replacement of good devicesCost of repair and associated retestPossible damage to product during repairLongevity of reworked product vs. product that is untouched
42 What Is Needed to Prevent Damage? Driver Voltage and Current VerificationLow impedance, closed loop measurementPer Pin Programmable Voltage Levels>5 logic families per device ( 1.0,1.2,1.5,1.8,2.5 and 3.3)Hardware Back-drive Limits for both Current and Time100mA’s maximum or ANY limit that is considered safeHigh Speed Digital ControllerMinimize test timeMulti level Software IsolationEliminate noise, clocks and feedback loops.
43 Technical PapersReliability limits for the gate insulator in CMOS technologyBy J. H. StathisCMOS scaling beyond the 100-nm node with silicondioxide-based gate dielectricsBy E. Y. Wu,E. J. Nowak,A. Vayshenker,W. L. Lai,D. L. HarmonDegradation and Breakdown of Thin Silicon Dioxide Films Under Dynamic Electrical StressMontserrat Nafr´ıa, Jordi Su˜n´e, David Y´elamos, and Xavier AymerichTime Dependent Breakdown of Ultrathin Gate OxideBy Abdullah M. Yassine, Member, IEEE, H. E. Nariman, Member, IEEE, Michael McBride, Mirac Uzer, Member, IEEE,and Kola R. Olasupo, Member, IEEEIssues and Challenges of Testing Modern Low Voltage Technologies with Traditional In-circuit TestersAlan Albee, APEX 2004
44 “Impact of Low-Voltage Devices on Test and Inspection” Teradyne Assembly Test Division Website:Michael J Smith
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