ddr2 dram high-frequency test at probe (hftap) · 2020. 7. 1. · wafer-level final-sort challenge...
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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
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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
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p. 3
Southwest Test Workshop 20056/6/2005 Elpida / FFI
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
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p. 4
Southwest Test Workshop 20056/6/2005 Elpida / FFI
High Performance K3 Probing SolutionHFTAPTM probing technology
FFI K3 probing technology
K3 performance enables DDR2 testing @ 333MHz / 667Mbs
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p. 5
Southwest Test Workshop 20056/6/2005 Elpida / FFI
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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p. 6
Southwest Test Workshop 20056/6/2005 Elpida / FFI
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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p. 7
Southwest Test Workshop 20056/6/2005 Elpida / FFI
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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p. 8
Southwest Test Workshop 20056/6/2005 Elpida / FFI
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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p. 9
Southwest Test Workshop 20056/6/2005 Elpida / FFI
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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p. 10
Southwest Test Workshop 20056/6/2005 Elpida / FFI
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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p. 11
Southwest Test Workshop 20056/6/2005 Elpida / FFI
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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p. 12
Southwest Test Workshop 20056/6/2005 Elpida / FFI
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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p. 13
Southwest Test Workshop 20056/6/2005 Elpida / FFI
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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p. 14
Southwest Test Workshop 20056/6/2005 Elpida / FFI
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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p. 15
Southwest Test Workshop 20056/6/2005 Elpida / FFI
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)
These are evaluated at high temperature with Vdd set in 3points.
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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p. 16
Southwest Test Workshop 20056/6/2005 Elpida / FFI
Elpida evaluation: Correlation (AC parameters) 2
These are evaluated at high temperature with Vdd set in 3points.
・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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p. 17
Southwest Test Workshop 20056/6/2005 Elpida / FFI
Elpida evaluation: Correlation (Idd)
Correlated well
These are evaluated at high temperature with Vdd set in 3points.
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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p. 18
Southwest Test Workshop 20056/6/2005 Elpida / FFI
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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p. 19
Southwest Test Workshop 20056/6/2005 Elpida / FFI
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
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