G R A N T R E Y N O L D S

S U R F S T U D E N T

S E M I C O N D U C T O R A N D D I M E N S I O N A L M E T R O L O G Y D I V

C M O S D E V I C E – R E L I A B I L I T Y G R O U P

M E N T O R ( S ) : J A S O N R Y A N A N D J A A F A R C H B I L I

Massively Parallel Reliability Test System

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Semiconductor Reliability

What is reliability testing within electronics?

Accelerated lifetime testing

Elevated temperatures and increased voltages

Why is reliability so important?

Ensuring it will last

Projecting how long it will last

(at normal conditions)

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Semiconductor Reliability Testing

System reliability (billions of devices)

Inferred from device level (single device)

Performance vs reliability

Satellite vs cell phone

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Traditional Testing

Current method of testing

Probing stations

Drawbacks of probe stations

Four to eight probe pins

Limited testing capacity

Expensive

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Issues in Current Reliability Testing

Can’t test a transistor for 10 years

But too much acceleration produces unreliable statistics

New/Advanced transistors require more samples Gate oxide thickness fabrication variability

Accurate lifetime models require many test conditions

“Reliability testing is the bottleneck

of technological development”

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The Massively Parallel Reliability System

What is the MPRS? Goal: produce accurate lifetime projections of semiconducting devices

Long-term Goal: provide a universal standard reliability platform that can test for all the degradation modes in semiconductor devices

Statistics on lots of devices = Accurate lifetime projection

Why did NIST create this system? Solves probing station problems:

Cost/Time

Lots of statistical data on devices

Up to 3000 devices

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Experimental setup of MPRS

How does it work?

Thirty mini 100 probe pin stations

PCB does device monitoring and stressing

Temperature board for chuck and die

microscope

Loading position

Computerplatform

micromanipulator

temperature control

electronics

Stress and measure

electronics

MetalchuckVacuum

Heating filament

a) b)

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I/O Physical Interface

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Control and Measurement Interface

Measurements and data within MPRS

PCB measures, monitors, and controls critical reliability failure

(aka “the breakdown of the device”)

How the testing works

Device to microcontroller I/O interfaces built depending on type of semiconductor and type of test

Which failure mode we are interested in

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TDDB – time dependant dielectric breakdown

Dielectric breakdown

TDDB - thin oxide SiC

Different PCB

Different I/O interface

TDDB – thick oxide on SiC

SiC MOS capacitors

Thick oxide devices call

for robust I/O interface

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SiC Thick Oxide Boards

Previous board

64 Individual switches => 64 devices

Cross talk

Noise

New Board

Implements high voltage switch

arrays (up to 100V)

2 sets of seven switch arrays

Stressing and measuring

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How Do We Measure and Stress?

2 sets of seven channels

16 devices per channel (16 bit switch array)

112 switches but only 100 devices

Controlling the switches

ADC

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Device under test (DUT)

LabVIEW program

Call Library Function nodes

Dynamic Link Library

USB Communication

ProcessIO( )

PIC Firmware

Breakdown of Testing Structure

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Hierarchy of LabVIEW

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Getting Things to Work

Logical mapping of what needs to happen

Break map into smallest component and start to test

Build a VI, a DLL routine, and a PIC firmware case

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Getting Things to Work Properly

Finding the smallest possible step forward

Testing the step

Change one thing

Test again

Finding ways to test new code

Probing

Sending information back to labVIEW

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Conclusion/Summary

MPRS drastically increases reliability testing capacity

Provides good statistics from large sample sizes

This is important because….

MPRS design standard

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Acknowledgements

Special thanks to:

Jason Ryan

Jaafar Chbili

Zakariae Chbili

Charles Cheung

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