A Solution of Test,
Inspection and Evaluationfor Blind Signal Waveform
on a Board
Tatsumi Watabe, Makoto Kawamura, &Hiroyuki Yamakoshi
S.E.R. Corporation
Conference Readymm/dd/20142016 BiTS Workshop
March 6 - 9, 2016

Purpose Blind signal waveform analysis on the systemboard by using Signal Probe Socket.

Conclusion

 Got a real signal waveform byintroduction S-parameter data of signal
probe socket and InfiniiSimperformance.

A Solution of Test, Inspection and Evaluation for Blind Signal Waveform on a Board

2Agenda
1) What is a blind signal analysis?
2) Signal probe socket !
2-1) YOROI ???
3) Blind signal measurement & data4) Conclusion & summary

A Solution of Test, Inspection and Evaluation for Blind Signal Waveform on a Board

31) What is a blind signalanalysis ?

A Solution of Test, Inspection and Evaluation for Blind Signal Waveform on a Board

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Blind Signal !

A Solution of Test, Inspection and Evaluation for Blind Signal Waveform on a Board

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Blind signal analysis !
 Timing analysis between DDR and CPU.
 Measure and confirm a blind signal waveform
directly underneath IC package.
 Define different approach for identification of afailure point when not re-appearance on LSI tester.
 Qualification of memory and CPU.
 Moving measurement point by using InfiniiSim.

A Solution of Test, Inspection and Evaluation for Blind Signal Waveform on a Board

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Timing signal & waveform
Timing analysis
Verification
Quality control

DDR Clock

Hold Time

Write and Read waveform
Set up Time
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Blind signal measurement
1. All signals of 0.8mm pitch device shouldbe accessible for measurement.
2. Support of high- speed signal
measurements over 3.5 Gbps.
3. Solderless mount.
(Easy to replace the target IC)

A Solution of Test, Inspection and Evaluation for Blind Signal Waveform on a Board

82) Signal Probe Socket !

A Solution of Test, Inspection and Evaluation for Blind Signal Waveform on a Board

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Blind signal probing

Signal measurement on DVD player

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Blind signal probing

Signal probe socket is on a board of DVD player andconnected to the oscilloscope.
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Blind signal probing
Removed DDR memory and mounted signal
probe socket worn YOROI.

＋A Solution of Test, Inspection and Evaluation for Blind Signal Waveform on a Board

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Setup for DDR memory’s blind signal
measurement
IC socket

Measurement point
DDR memory

Interposer PCB

Oscilloscope
Other components

DVD player
PCB assembly

Removed DDR
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Signal probe socket basic structure

Example
PKG: BGA (DDR3 memory)
Pitch: 0.8mm
Pin count: 96 pin
A Solution of Test, Inspection and Evaluation for Blind Signal Waveform on a Board

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Actual performance of DDR memory’s
signal probe socket

Shmoo plot analysis result
1.5Gbps

Tester-Verigy-V93000-HSM3600
3Gbps
1.25V

1.425V 1.5V 1.575V

1.75V

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Blind signal probing design structure
YOROI structured
mount is required forsignal probe socket

A Solution of Test, Inspection and Evaluation for Blind Signal Waveform on a Board

162)-1 YOROI ???

SAMURAI wore
YOROI for fighting.
And signal probe
socket also must be.

Why ?
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YOROI structure for signal probe socket(Patent pending)
A Solution of Test, Inspection and Evaluation for Blind Signal Waveform on a Board

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Signal probe socket worn YOROITop plate
PCB assembly

Probe & Interposer
Bottom plate
Floating nest
(Patent pending)
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Interposer element
It influences the measurement of theblind signal waveform.
Waveform measured
directly underneath the ball・Directly underneath the ball (real signal)

・Waveform at measurement point

Equivalent circuit model
PCBLCInterposer pattern for measurement (stub)
A Solution of Test, Inspection and Evaluation for Blind Signal Waveform on a Board

203) Blind signal measurement& dataA Solution of Test, Inspection and Evaluation for Blind Signal Waveform on a Board

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Testing procedure & method
Target is this signal waveform
DDR Memory

Measurement point oninterposer
Measurement point
DDR Memory

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Actual DDR clock signal waveform
Red : Directly underneath the ballBlue : Waveform at measurement point

A Solution of Test, Inspection and Evaluation for Blind Signal Waveform on a Board

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Waveform transformation

InfiniiSim by Keysight Technologies

A Solution of Test, Inspection and Evaluation for Blind Signal Waveform on a Board

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S-parameters of signal probe socket
Actual S-parameter data of signal probe socket

(a)

(b)

(c)

Measurement point
⒜

(c)

(b)

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Waveform transformation
Measurement point waveform includes
all S-parametric data of (a),(b) and (c)(a),(b) and (c) must be subtracted frommeasurement waveform to get the actual
data of the IC terminal.

Waveform transformation

DUT Ball/Pad⒜(b)(c)
PCB PadA Solution of Test, Inspection and Evaluation for Blind Signal Waveform on a Board26

Testing procedure & method
Test point directly underneath the ball
DDR Memory

Measurement point

DDR Memory

Measurement point on interposer

DDR Memory

Measurement point after using InfiniiSim
transformation

Moving measurement point
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DDR clock signal waveform transformed
Red : Directly underneath the ballBlue : Waveform at measurement point
Green : Waveform after transformation by InfiniiSim

A Solution of Test, Inspection and Evaluation for Blind Signal Waveform on a Board

284) Conclusion & Summary

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Conclusion & Summary
1. The signal probe socket can measure blind signal
waveform behind of IC package.
2. Blind signal waveform is able to reform by InfiniiSim
using S-parameter data of signal probe socket.

3. It bring system engineers significant system
performance information detail.
4. It is a new approach for evaluation & analysis in theworld.
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Future works
1. Support high speed DDR4 memory
Minimize stub
Minimize probe length
4.3mm ⇒2.6mm
And for 10GHz speed requirement

2. Approach power integrity analysis
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Acknowledgements

Keysight Technologies Japan
Hiroyuki Shimada（MoDech inc)

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Appendix

R= 80 ΩR= 25 ΩA Solution of Test, Inspection and Evaluation for Blind Signal Waveform on a Board33