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An Information-Driven FEA Model Generation Approach

for Chip Package ApplicationsSai Zeng1, Russell Peak2*, Ryuichi Matsuki3,

Angran Xiao4, Miyako Wilson2, Robert E. Fulton1

1 Engineering Information Systems Lab2 Manufacturing Research Center

4 Systems Realization Lab

Georgia Institute of Technology, Atlanta, GA 30332-0405, USA

3 Advanced Product Design & Development Division,

Shinko Electric Industries Co., Ltd., Nagano, Japan

23rd Computers and Information in Engineering Conference

September 2–6, 2003, Chicago, Illinois

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Example Chip Package Products Source: www.shinko.co.jp

Plastic Ball Grid Array (PBGA) Packages Quad Flat Packs (QFPs)

Wafer Level Package (WLP) System-in-Package (SIP)Glass-to-Metal Seals

3

12

3

12

3

12

4

1a

2

3a

1b

1c

3b 3c

3a 3b

2

1a 1b 1c

1d 1e

3

1a 1b

1c1d

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4a 4b 4c

Idealized Analytical Bodies Decomposed FEA Geometry Models

original

topology change (no body change)

body change (includes topology change)

Variable Topology Multi-Body (VTMB) FEA Meshing Challenges

Labor-intensive “chopping”

Meshing & SolvingDesign

Model

4

Traditional Approach

Analysis Concepts Geometry Preparation for Mesh Generation

FEA Model Planning Sketches in Traditional Approach

Small topology changes force mesh model rebuilding from scratch

Mesh models are barely reusable using traditional approach

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Motivation

Competition in Chip Package Industry Needs for new technologies and approaches facilitating seamless

design and analysis integration Difficulty in analysis model generation

– Hundreds of components– Variable materials– Complex geometric shapes– Changeable connectivity configurations

Modifications resulting in tedious and time consuming FEA modeling process

– package design– analysis discipline– idealization

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Objective

Integrate chip package design using Finite Element Analysis

Automate the FEA modeling process to save the modeling time and reduce the human errors

Increase reusability of the mesh models during chip package modification and redesign

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Frame of Reference – Multi-Representation Architecture (MRA)for CAD-CAE Interoperability

Composed of four representations (information models) Provides flexible, modular mapping between design & analysis

models Creates automated, product-specific analysis modules (CBAMs) Represents design-analysis associativity explicitly

1 Solution Method Model

ABB SMM

2 Analysis Building Block

4 Context-Based Analysis Model3

SMMABB

APM ABB

CBAM

APM

Design Tools Solution Tools

Printed Wiring Assembly (PWA)

Solder Joint

Component

PWB

body3body2

body1

body4

T0

Printed Wiring Board (PWB)

SolderJoint

Component

AnalyzableProduct Model

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Information-Driven FEA Modeling Approach

Mapping process ABBΨRMM transforms the ABB model into a ready-to-mesh model (RMM) by geometry decomposition.

Mapping process RMMΨSMM transforms the RMM into the solvable FEA-based SMM in an automated manner.

ABB captures analytical concepts FEA based SMM = object wrapper

– Integrates pre-processor, solver and post processor information– Includes vendor-specific script file format

body3body

2

body1

body4

T0

body3body

2

body1

body4

T0

ABB Model RMM Model SMM Model

ABBΨRMM RMMΨSMM

Information-Driven FEA Modeling Approach

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Analysis Building Block Models (ABBs)

An ABB model represents engineering analytical concepts as a set of computable information entities

Independent from specific solution techniques Analysis knowledge is captured by employing object-orient information representation

technology

a. Composition Hierarchy for ABB Continuum Systems

Continuum System

Load Structure

Continuum Connectivity Support

Shape Materials

Continuum System

Load Structure

Continuum Connectivity Support

Shape Materials

b. ABBs Catetorized by Type [1,2]

Analysis Primitives - Primitive building blocks-

Loading Variablesq(x)

Distributed Load

Temperature,Stress,Strain,

T

Loading Variablesq(x)

Distributed Load

Temperature,Stress,Strain,

Tq(x)

Distributed Load

Temperature,Stress,Strain,

T No-Slipbody 1

body 2

ConnectivityNo-Slip

body 1

body 2 No-Slipbody 1

body 2

body 1

body 2

Connectivity

Material Models

Linear-Elastic

BilinearPlastic

Low CycleFatigue

N

Material Models

Linear-Elastic

BilinearPlastic

Low CycleFatigue

N

Material Models

Linear-Elastic

BilinearPlastic

Low CycleFatigue

N

Linear-Elastic

BilinearPlastic

Low CycleFatigue

N

N

- Cantilever Beam SystemAnalysis Systems

x

y q(x)

Beam

Distributed Load

RigidSupport

- Cantilever Beam SystemAnalysis Systems

x

y q(x)

Beam

Distributed Load

RigidSupport x

y q(x)

Beam

Distributed Load

RigidSupport

RigidSupportRigidSupport

Support

ShapeShapeShapeContinua

Beam

Plane Strain Body Plate

Continua

Beam

Plane Strain Body Plate

Continua

Beam

Plane Strain Body Plate

body3body2

body1

body4

T0

body3body2

body1

body4

T0

ABB Model RMM Model SMM Model

ABBΨRMM RMMΨSMM

body3body2

body1

body4

T0

body3body2

body1

body4

T0

body3body2

body1

body4

T0

body3body2

body1

body4

T0

ABB Model RMM Model SMM Model

ABBΨRMM RMMΨSMM

Information Content for Example ABB Concepts

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Analysis Building Block Models (ABBs)

A diving board example is presented to illustrate an ABB system

L1: Loading RelationC1: Connectivity RelationC2: Connectivity RelationS1: Support Relation

a. Diving Board Example

b. ABB Model Graphical View

L1L1

C1 C2

C1 C2

S1

Uniform pressure

Slip No-slip

Continuum A

Continuum B

Fully constraint

A Graphical View of an ABB System and its Analytical Bodies and Connectivity

body3body2

body1

body4

T0

body3body2

body1

body4

T0

ABB Model RMM Model SMM Model

ABBΨRMM RMMΨSMM

body3body2

body1

body4

T0

body3body2

body1

body4

T0

body3body2

body1

body4

T0

body3body2

body1

body4

T0

ABB Model RMM Model SMM Model

ABBΨRMM RMMΨSMM

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Ready-to-Mesh Models (RMMs)

A RMM is obtained by geometric decomposition from a corresponding ABB

The geometry of a RMM model is composed of geometry pieces that are convex-shaped and meshable using efficient and cheap meshing techniques.

Building blocks of an ABB can be reused to construct a RMM Associativity of building blocks is changed before and after

decompositionL1L1 L1L1

C1C1 C1C1

C1C1C1C1

C2C2

C2C2S1S1

S1S1

S1S1

A Graphical View of an RMM System and its Decomposed Bodies and Connectivity

body3body2

body1

body4

T0

body3body2

body1

body4

T0

ABB Model RMM Model SMM Model

ABBΨRMM RMMΨSMM

body3body2

body1

body4

T0

body3body2

body1

body4

T0

body3body2

body1

body4

T0

body3body2

body1

body4

T0

ABB Model RMM Model SMM Model

ABBΨRMM RMMΨSMM

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Decomposition Architecture

Decomposition is implemented to obtain conformal mesh along the interfaces of connected bodies

Decomposition deals with geometry exclusively

Decomposed model consists of decomposed bodies connected along equivalent faces

Topology and GeometryFeature Recognition

Seperator Setup

Decomposition

Meshable?

RMM Geometry

ABB Geometry

Y

N

Decomposition Process

body3body2

body1

body4

T0

body3body2

body1

body4

T0

ABB Model RMM Model SMM Model

ABBΨRMM RMMΨSMM

body3body2

body1

body4

T0

body3body2

body1

body4

T0

body3body2

body1

body4

T0

body3body2

body1

body4

T0

ABB Model RMM Model SMM Model

ABBΨRMM RMMΨSMM

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Decomposition Associativity Mechanism

An mechanism is required to keep track of the information associativity during the geometry decomposition

Continuum A

Uniform pressure

Compositional Relations for Boundary Condition Building Blocks and Continuum Building Blocks after Decomposition

body3body2

body1

body4

T0

body3body2

body1

body4

T0

ABB Model RMM Model SMM Model

ABBΨRMM RMMΨSMM

body3body2

body1

body4

T0

body3body2

body1

body4

T0

body3body2

body1

body4

T0

body3body2

body1

body4

T0

ABB Model RMM Model SMM Model

ABBΨRMM RMMΨSMM

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Solution Method Model (SMM)

It is an information entity that wraps solution tool inputs and outputs into a single logical package

SMM includes the SMM information objects and the SMM tool agent

1 Solution Method Model Solution Tools

preprocessormodel

meshmodel

resultsextrema

u

A

3

11 10

98

4 3

2

7

56

1

A

A2

1

CL Files

Operating SystemObject Environment

ToolAgent

inputs &control

outputs

FEA Tools

body3body2

body1

body4

T0

body3body2

body1

body4

T0

ABB Model RMM Model SMM Model

ABBΨRMM RMMΨSMM

body3body2

body1

body4

T0

body3body2

body1

body4

T0

body3body2

body1

body4

T0

body3body2

body1

body4

T0

ABB Model RMM Model SMM Model

ABBΨRMM RMMΨSMM

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ABB - SMM- Solution Tool Interaction

ABB systems generate SMMs based on solution method considerations

– Via RMMs in these problem types

Solution tool capabilities are also usually considered

1 Solution Method Model

2 Analysis Building Block Solution Tool

inputs &control

outputs

A1

3

2

A

A

11 10

98

4 3

2

7

56

1

A1

3

2

A

A

11 10

98

4 3

2

7

56

1

preprocessormodel

meshmodel

4body

ABB SMM

resultsextrema

u

1body

3body

2body

ABBSMM

RMM Model

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A Chip Package Thermomechanical Analysis Case – An ABB system

Four linear elastic thermomechanical continua Continua are glued together One rigid pin support Uniform temperature drop as thermal load

DieDie Attach

Mold

Die Pad

Front View

Right View

Time

TemperatureDifference

Load

a. ABB System - Original Bodies with 1/4 Symmetry

Support

Continuum BodiesNo Slip

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A Chip Package Thermomechanical Analysis Case – An RMM

Front View

Right View

b. RMM System - Decomposed Bodies

A RMM is obtained after automatic decomposition of a ABB system With composition mechanism, information associated with geometry

can be assigned on the corresponding decomposed geometry This model can be directly input into the SMM to generate a conformal

FEA meshed model

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A Chip Package Thermomechanical Analysis Case – An SMM

c. FEA SMM - Tool-specific Model

The tool agent translates the model information into the tool-specific computable formats, e.g. a PATRAN command language ASCII file

Modeling time is counted as information instance object creation time

Modeling time is dramatically reduced comparing to traditional FEA modeling approach

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Complex Chip Package Thermomechanical Analysis Case

ABB Model consisting 182 Input bodies RMM consisting 9056 Decomposed bodies

FEA SMM

Decomposition

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Closure

Presentation of information-driven FEA modeling approach

Demonstration representing product-independent analysis concepts as knowledge-based objects:

– semantically rich– reusable– modular and tool-independent

Reduction of FEA modeling time (variable topology multi-body application) - reduced from days/hours to hours/minutes

Enhancement of knowledge capture and automation level vs. traditional direct FEA modeling approaches

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Acknowledgements

We are particularly grateful for the support of the following

people: – Kuniyuki Tanaka, Yukiharu Takeuchi, and Shinichi

Wakabayashi of Shinko Electric Ltd. – Greg Bettencourt of Shinko Electric America, Inc.– Rod Dreisbach of The Boeing Company– Mike Dickerson of the NASA Jet Propulsion Lab (JPL)– Manas Bajaj, Greg M. Mocko, Edward J. Kim, Injoong Kim at

the Engineering Information Systems Lab, Georgia Tech

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Question?