September 13, 2016 Session 2

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Session 2

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The presentations in this publication comprise the pre-workshop

Proceedings of the BiTS China Workshop. They reflect the authors’

opinions and are reproduced here as they are planned to be presented

at the BiTS China Workshop. Updates from this version of the papers

may occur in the version that is actually presented at the BiTS China

Workshop. The inclusion of the papers in this publication does not

constitute an endorsement by the BiTS Workshop or the sponsors.

There is NO copyright protection claimed by this publication. However,

each presentation is the work of the authors and their respective

companies: as such, it is strongly encouraged that any use reflect

proper acknowledgement to the appropriate source. Any questions

regarding the use of any materials presented should be directed to the

author/s or their companies.

The BiTS logo, ‘Burn-in & Test Strategies Workshop’, ‘BiTS China’, and ‘Burn-in & Test Strategies China Workshop’ are trademarks of BiTS Workshop.

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Session Chair

Socket Technology

"Study of Probe Pin Internal Resistance"

Takuto Yoshida - Test Tooling Solutions Group

"Monte Carlo Analysis for PoP Alignment"

DeXian (Frank) Liu - Smiths Connectors

"

Conductive Elastomer vs Spring Probe: Performance &

Application"

Jiachun (Frank) Zhou - Smiths Connectors

"

Do Socket and Kits Design Matter for Die Cracking?"

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Session Chair

Socket Technology

"

弹

簧探

针

内部阻

值

的研究

"

Takuto Yoshida - Test Tooling Solutions Group

"

叠

层

封装

测试

插座

设计

中校直的蒙特卡洛分析法

"

刘德先

_{— Smiths Connectors}

"

导电

胶与

弹

簧探

针

技

术

的比

较

以及在半

导

体

测试领

域的

性能与

应

用

_"

周家春（

_Frank

）博士，刘德先

_{— Smiths Connectors}

"

测试

插座和快速切

换

治具的

设计对

芯片碎片的影响

_"

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Monte Carlo Analysis

for PoP Socket Alignment

DeXian Liu

（

Frank)

Resty Querubin

Siang Soh

Smiths Connectors

Conference Ready mm/dd/2014

BiTS China Workshop

Suzhou

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• Basic: PoP Technology

• Basic: PoP Test Setup

• Why Tolerance Analysis?

• Basic Tolerance Analysis Tool

• PoP Socket Alignment Analysis

• Outputs and Results

• Summary

2 Monte Carlo Analysis for PoP Socket Alignment

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3

Basic: PoP Technology

PoP (Package on Package)

‒

A package technology to

combine two discrete packages

together vertically: a package

on top of another

‒

Top package has fewer

connectors than bottom

package

‒

Package type: primarily BGA

‒

Top side of bottom package:

BGA or LGA

Memory

Processor

PCB

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4

Basic: PoP Test Setup

Test Setup 1: Test Two Packages

‒

The memory (known good) and

processor packages are tested in

one setup (socket)

‒

Mostly for manual test only

Test Setup 2: Test Bottom

Package

‒

Only processor package (bottom)

is tested in one setup (socket)

‒

Both auto and manual tests

Top side PCB

Processor

Top side

pin

Bottom

side pin

Return

path pin

PCB

Processor

Memory

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• Design verification

• Optimize design for manufacturing feasibility

• Reduce manufacturing costs

Why Tolerance Analysis?

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6

Basic Tolerance Analysis

• Worst Case Analysis (WC)

• Root Sum Squared (RSS or MRSS)

• Monte Carlo (MC)

Monte Carlo Analysis for PoP Socket Alignment

Worse Case RSS Monte Carlo

Assumptions

1. Independent parameters required

2. Linear functions only 3. 6-sigma is assumed

1. Independent parameters required

2. Linear functions only 3. Normal distribution desired. 1. Dependent parameters are OK 2. Non-linear functions are allowed

3. Any (and mixed) distributions allowed

Limitation One-or-Zero (like)

(GO/NO-GO gauge) only

One-or-Zero (like)

(GO/NO-GO gauge) only

Yield / Cpk / DPM can be computed

Applications

Early assessment where process distributions are unknown

Linear functions with normal input distributions

All linear or non-linear applications

Example Max total =

(1+0.3) + (2+0.4) = 3.7

RSS total =

1 + 2 + (0.32+0.42)0.5 = 3.5 TBD

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Schematic

ZH J A delta D L M R C’ I E B P X BLADE-PAK TOP SOCKET INTERPOSER BOTTOM SOCKET DOCKING PLATE Y Z ZI ZE Q

Note: This is a generic drawing to define the parameters

PARAMETERS NOT USED IN THIS ANALYSIS Top Socket

Alignment Only

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September 13, 2016

Burn-in & Test Strategies Workshop www.bitsworkshop.org

Assumptions

‒

All normal input features have a Cp of 1

‒

This analysis focuses on the top socket alignment only

‒

Failure criteria below:

• M-C’ Top Alignment Cpk

M-C’ PAD ALIGNMENT (Edge of Pad to center of probe)

Monte Carlo Analysis for PoP Socket Alignment 8

‒

Major parameters affected:

• Package size tolerance

• Package pad diameter

• Package pad true position

• Cavity true position

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Schematic:

Socket Structure / Package Information

‒

Outline Tolerance:

‒

Pad size and tolerance: Φ0.28±0.02mm

‒

Pad TP:

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Output:

Current Spec

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Output:

Current Spec

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Output:

Current Spec (+/-0.05 mm)

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Output:

Sensitive Graph-Change in Cavity Hole TP

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Output:

Sensitivity Graph-Change in Cavity Hole TOL

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Results Summary

Reducing package pad true position diameter will get higher MC Cpk

Reducing pad diameter will get lower MC Cpk

MC Top Alignment

Package spec

TP diameter

Pad diameter

(mm)

MC Cpk

Sigma Cpk

Design 1

0.15

0.28

1.03

1.10 Design 1

0.08

0.28

1.42

1.62 Actual measured socket

0.15

0.28

1.04

1.11 Actual measured socket

0.08

0.28 N/A

1.64 Design 1

0.15

0.24

0.78

0.85 Design 1

0.08

0.24

1.14

1.28 Design 2

0.15

0.24

0.80

0.87 Design 2

0.08

0.24

1.22

1.35

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Results:

% Contribution For Design Change

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September 13, 2016

Burn-in & Test Strategies Workshop www.bitsworkshop.org

Monte Carlo Analysis for PoP Socket Alignment 21