DDR2 DRAM High-Frequency Test at Probe (HFTAP) · 2020. 7. 1. · Wafer-Level Final-Sort Challenge...

6/6/2005Southwest Test Workshop 2005

DDR2 DRAM High-Frequency Test at Probe (HFTAP)

Masahide Ozawa Elpida Memory, Inc. Yoichi Funatoko FormFactor Inc., Asia

Southwest Test Workshop 2005

p. 2

Southwest Test Workshop 20056/6/2005 Elpida / FFI

Presentation Outline• Introduction• DDR2 DRAM wafer-level-final-sort tests objectives

and goals• High performance probing technology solution• New probing technology internal qualification • Customer evaluation• Summary and conclusion• Follow on work

p. 3


Wafer-Level Final-Sort Challenge

2004 2005

Elpida : 333MHz DDR2 DRAMFFI : K3 [x30DUT]533MHz testerSWTW2005

Device Frequency(MHz)

300

200

100

Elpida : 100MHz Mobile RAMFFI : (S200, shared driver 200MHz)143MHz testerPresented at SWTW2004

p. 4


High Performance K3 Probing SolutionHFTAPTM probing technology

FFI K3 probing technology

K3 performance enables DDR2 testing @ 333MHz / 667Mbs

p. 5


0.5 1.0 1.50.0 2.0

-15

-10

-5

-20

0

fre q, GHz

dB(S

(4,1

))

m1

m2

m1freq=dB(S(4,1))=-1.004

142.0MHzm2freq=dB(S(4,1))=-3.004

877.0MHz

0.5 1.0 1.50.0 2.0

-40

-30

-20

-50

-10

fre q, GHz

dB(S

(2,1

))

m3

dB(S

(3,1

))

m4

m3freq=dB(S(2,1))=-23.964

277.0MHzm4freq=dB(S(3,1))=-31.299

277.0MHz

FFI Attenuation & Cross-talk Simulation

Attenuation Cross-talk

Near-EndFar-End

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FFI Internal qualification Tpd Distribution by TDR Measurement

1.42 1.43 1.44 1.45 1.46 1.47 1.48

100.0%99.5%97.5%90.0%75.0%50.0%25.0%10.0%2.5%0.5%0.0%

maximum

quartilemedianquartile

minimum

1.4810 1.4772 1.4720 1.4640 1.4575 1.4515 1.4465 1.4396 1.4325 1.4270 1.4220

QuantilesMeanStd DevStd Err Meanupper 95% Meanlower 95% MeanN

1.4518250.00948680.00035361.45251911.4511309

720

MomentsFFI_(ns)

Distributions

Channel to channel skew was +/- 30ps

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Elpida Evaluation Items• Basic characteristic

– Skew– Waveform– Tr/Tf– Jitter

• Device evaluation– At-speed test– Correlation between wafer and package

TCK-VDD ShmooAC parametersIdd current

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Elpida evaluation:Channel to Channel Skew

Tpd Distribution of HFTAP Probe Cards

020406080

100120140160180

-30 -25 -20 -15 -10 -5 0 5 10 15 20 25 30

Difference from average [ps]

Cou

nt

23.27.7

3σ[ps]σ[ps]

Tpd spec （±75ps） is satisfied.

σ: Standard Deviation

n=576

(TDR Measurement)

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Elpida evaluation: Input Waveform (Amplitude 0.5V Vt:0.9V )

①

0ps 937.5ps

②

0ps 1875ps① ②

③

0ps

937.5ps

1875ps

③

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Elpida evaluation: Tr/Tf (Amplitude 0.5V 20-80%, Vt:0.9V )

Tr Tｆ

Tr/Tf of K3 probe card

277304

325

399

0

100

200

300

400

500

Tr Tf Tr Tf

Driver I/O

Tr/

Tf

[ps]

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Elpida evaluation: Jitter

110ps

※Evaluated at 533MHz

The source of jitter is caused by attenuation, cross talk, and tester timing control.

Jitter of K3 is similar of existing final tester

Jitter of K3 Probe Card

110 114122

142

0

50

100

150

Rise Fall Rise Fall

Driver I/O

Jitte

r [ps

]

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Elpida evaluation: At-Speed Test (1)

High-speed WT Assembly Package Test

PC533

PC667

Packaging separately divided by the result of High-speed WT

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Elpida evaluation: At-Speed Test (2)• Correlation Result

Correlation test result

was similar to final test.

CorrelationRatio

K3 87.0%

Correlation of at-speed test between wafer and package

0% 20% 40% 60% 80% 100%

PC533

PC667

Resu

lt o

f W

afer

Test

Result of Package Test

upgrade

same grade

downgrade

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Elpida evaluation: Correlation (core test)

Correlated well

These are evaluated at high temperature with Vdd set in 3points.

White line means “Be equal” for wafer test and package test. If plot is near this white line, correlation is OK.

Test Item: TCK-VDD Shmoo for some pattern

CoreTest correlation of K3

0

10

20

30

40

50

0 10 20 30 40 50

Package Test Result [ns]

Waf

er

Test

Resu

lt [

ns]

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AC Parameter Correlation of K3

0.0

0.2

0.4

0.6

0.8

1.0

0.0 0.2 0.4 0.6 0.8 1.0Package Test Result [ns]

Waf

er T

est R

esul

t [ns

]

AC Parameter Correlation of K3

0.0

0.5

1.0

1.5

2.0

2.5

3.0

0.0 0.5 1.0 1.5 2.0 2.5 3.0Package Test Result [ns]

Waf

er T

est R

esul

t [ns

]Elpida evaluation: Correlation (AC parameters) 1

※Sub line is indicated the range of Timing accuracy (±100ps)


Test Item: AC Parameters (setup, hold, TCK etc.)

Compared by package test result•Different 100ps～150ps for some test item

Available for testing with adjustment

Zoom up

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Elpida evaluation: Correlation (AC parameters) 2


・40mV higher VIH for specificpins

Available for testing with adjustment

Test Item: AC Parameters (VIH/VIL)

VIH/VIL Correlation for K3

0.00

0.04

0.08

0.12

0.16

0.00 0.04 0.08 0.12 0.16

Package Test Result [V]

Waf

er T

est R

esul

t [V

]

All Itemsome VIH

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Elpida evaluation: Correlation (Idd)

Correlated well


Test Item: Idd Current

Idd Correlation for K3

0

50

100

150

200

250

300

0 50 100 150 200 250 300

Package Test Result [mA]

Waf

er T

est R

esul

t [m

A]

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Summary and Conclusion

Correlation test result was similar to final test.

Correlation between wafer and package test

Available to device measurement for 333MHz

DDR2 DRAM at device speed testing

High-frequency wafer testing

PC667 (333MHz) evaluation passed all criteria.

Basic characteristics(Waveform, Tr/Tf, Jitter)

ResultsObjectives

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Follow-on Work• Elpida Memory, Inc.

– Further evaluation for volume production

• FormFactor, Inc.– Higher parallelism K3 [x64 DUT & x 128 DUT] – Production qualification at > 300 MHz.– Customer evaluation for 500MHz and beyond with K5

DDR2 DRAM High-Frequency Test at Probe (HFTAP) · 2020. 7. 1. · Wafer-Level Final-Sort Challenge...

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