Taguchi Method and SPC system in Semiconductor Manufacturing

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Taguchi Method and SPC system in Semiconductor
Manufacturing
Chin-Yuan Chen ???Quality ManufactoryAdvance
Semiconductor Engineering Manufacturing Company,
Ltd Fisher_Chen_at_aseglobal.com

April 30, 2010
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Abstract
This presentation will cover the following
topics, Taguchi Method Application in Assembly
and Testing Site, SPC appliation system in
Assembly process.

• First, to present basic process introduction of
  semiconductor of assembly and testing. Taguchi
  Methodology and examples of assembly/test will be
  shown. To assist engineers to find root casue and
  enhance process capability, reduce variance,
  improve process capacity. Our company offer
  complete statistic training to new engineers.
• However, SPC methodology is most important tool
  for process control. To understand SPC concept,
  QC tools and OCAP(Out of Control Action Plan)
  become basic request of engineers.
• JMP software

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The statistical software in ASE
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The statistical software in ASE
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Content

• Assembly/Test brief introduction
• 2. Taguchi Method in test site
• - Enhance wrinkle bump yield
• 3. Taguchi Method in Assembly site
• - Gold Wire Diameter Reduction Evaluation
• 4. SPC in Assembly site

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• 1. Assembly/Test brief introduction

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What common point they had?
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ASE VisionThe Comprehensive Solution
Module, Board Assembly Test (DMS)
Final Test
Assembly
Wafer Bumping/Probing
Foundry
Materials
Circuit Design
Engineering Test
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Brief Assembly Process
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Brief Assembly Process
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Brief Assembly Process
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Brief Assembly Process
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Brief Test Process
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Brief Test Process
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• 2. Taguchi Method in test site

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• Bump Status Check

Wrinkle bump issue
Low Yield
Normal bump
Wrinkle bump
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Test Pin
Test Pin
Normal Bump
Wrinkle Bump
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Normal Bump
Wrinkle Bump
If you are engineer, then what will you improve?
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Hint
Good Contact
Good Yield
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Normal Bump
Wrinkle Bump
Contact deeper (Enhance Over Drive)
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• Taguchi Method

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• Taguchi Method - Analysis

To choose L9 Taguchi experiment matrix and
consider two response(y) as above table.
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• Taguchi Method- Analysis

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• 3. Taguchi Method in Assembly site

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• History

• Customer want cost saving with device, and to
  reduce gold wire diameter.
• Current diameter is 25um, customer request to
  reduce as 20 um.
• Current composition is Au, customer need to
  replace by Au-Pb.

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• Structure

652 golden wire
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• Taguchi Matrix

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• Taguchi Analysis Result

On Desirability Functions The desirability
functions are smooth piecewise functions that are
crafted to fit the control points. The minimize
and maximize functions are three-part piecewise
smooth functions that have exponential tails and
a cubic middle. The target function is a
piecewise function that is a scale multiple of a
normal density on either side of the target (with
different curves on each side), which is also
piecewise smooth and fit to the control points.
These choices give the functions good behavior
as the desirability values switch between the
maximize, target, and minimize values. For
completeness, we implemented the upside-down
target also. JMP doesn't use the Derringer and
Suich functional forms. Since they are not
smooth, they do not always work well with JMP's
optimization algorithm.
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• 4. SPC in Assembly site

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????(Enhance wrinkle bump yield, Gold Wire
Diameter Reduction Evaluation) ???????
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PBGA(??????)??
PBGA ?????