Dirk Zwemer1, Manas Bajaj2, Russell Peak2, Thomas Thurman3, Kevin Brady4, Sean McCarron1, Alex Spradling1, Michael Dickerson5, Lothar Klein6, Giedrius Liutkis6, and John Messina4

1. AkroMetrix LLC2. Georgia Institute of Technology3. Rockwell Collins, Inc.4. National Institute of Standards and Technology5. InterCAX, LLC6. LKSoftWare Gmbh.

PWB Warpage Analysis and Verification using an AP210 Standards-Based Engineering Framework and Shadow Moiré

AkroMetrix

EuroSimE 2004 www.eurosime.com Brussels, Belgium May 10-12, 2004

© All Rights Reserved. Permission to reproduce and distribute without changes for non-commercial purposes (including internal corporate usage) is hereby granted provided this notice and a proper citation are included.

Web version from http://eislab.gatech.edu/pubs/conferences/2004-eurosime-zwemer/ as of 2004-10-14

2

Warpage – Impact and Trends

Impact Low Manufacturing Yield High Rework of Interconnects Low Reliability More Severe with Higher Temperatures, Finer Pitch

Trends OEMs Enforcing New Warpage

Specifications on Suppliers. Temperature-Dependent Warpage Local and Global Warpage

3

Contents

Design-Analysis Interface within a Multi-Representation Engineering Framework

Experimental Verification using Temperature-Dependent Shadow Moiré

Initial Results and Future Development

4

Tree Structure of Multi-Representation Engineering Framework

MPMBare PWB

APMElectrical

APMMechanical

APMManufacturability

CBAMWarpage

CBAMPTH Fatigue

ABBLayered Shell

Effective Materials Properties

SMMFinite Element

Manufacturing Product Model

AnalyzableProduct Model

Context-BasedAnalysis Model

AnalysisBuilding Blocks

SolutionMethod Model

5

AP210 Standards-based Engineering Framework for Warpage Simulation

Solution Method Model

ABB SMM

Analysis Building Block

Context-Based Analysis Model

SMMABB

APM ABB

CBAM

APM

Manufacturing Product Model(STEP AP210-based)

Solution Tools(ANSYS, …)

Printed Wiring Assembly (PWA)

Solder Joint

Component

PWB

body3body2

body1

body4

T0

Printed Wiring Board (PWB)

SolderJoint

Component

AnalyzableProduct Model

6

Manufacturing Product Model (MPM) in anAP210 Standards-Based Engineering Framework

XaiToolsPWA-B

Eagle

LKSoft, …Gap-FillingTools

XaiToolsPWA-B LKSoft, …

Traditional Tools Mentor

Graphics

Manufacturing Product Model Components• STEP AP210

STEP-Book AP210,SDAI-Edit,

STI AP210 Viewer, ...

Instance Browser/EditorPWB Stackup Tool,…

ElectricalCAD Tools

pgpdm

Core PDM Tool

AP210interface

Doors

Slate

Systems EngineeringTools

- Eurostep AP233 Demonstrator- XaiTools AP233

7

AP210-based Manufacturing Product Model (MPM)cable_db example 2D PCB view and 3D Assembly view

As viewed in LKSoft AP210 STEP-Book

8

Analyzable Product Model (APM)Warpage Analyzable View of PWB

2D geometric structure

Orientation of each layer and associated features

Layer thickness and material properties

PCB outline

Comprised of straight lines and arcs (primitive level)

Mechanical (Tooling / Drilling) Hole

Circuit Traces

land

plated through hole

via

Footprint occurrence

This comprises of four lands, in this case. The component sits atop the lands.

Complete trace curve not shown

1 Oz. Cu

1 Oz. Cu

1 Oz. Cu

1 Oz. Cu

2 Oz. Cu

2 Oz. CuM150P2P11184

M150P1P21184

3 x 1080

3 x 1080

2 x 2116

9

Setting up context for warpage analysisAPM and ABB Creation

Grid (Sieve) Size

Single Layer View

…

Top view of “effective” grid elements in top layer of the PCB

…

Side view of the PCB with “effective” grid elements across

the stratums

thickness

wid

th

length

Given:

• Thermal loading profile

• Boundary Conditions (mostly displacement)

• Idealize PWB stackup as a layered shell

ABB ModelMPM / APM CBAM

Effective Material Property

Computation

CBAM attributes

• Thermal loading profile

• Boundary Conditions (mostly displacement)

• Idealize PWB stackup as a layered shell

10

Stage 1: Chopping the bare PWBCreating the ABB model

…

In this scenario, the plated through holes and vias are neglected (for simplicity).

Only the mechanical tooling holes are accounted for.

…

…

Case 1

Case 2

Case 3

Case 1

Case 2

Case 3

Board Edge Scenario 1

Board Edge Scenario 2

Tooling Hole Scenario 1

N columns

M rows

At the end of stage 1, an M X N grid of shapes (comprised of arcs and lines at the primitive level) would be available.

Operation during this stage is common across all stratums (as it deals with board outlines and tooling holes only – vias are disregarded)

11

Stage 2: Computing metallization ratio Creating the ABB Model

Consider a snapshot of metallization (traces and lands on stratum K)

…

…

…

…

J

I

Percentage metallization in the IJ th cell of stratum K is of interest. Let this percentage be

Effective material property IJK for cell IJ on stratum K is then computed as:

(1) IJK = ( / 100 ) * metal + ( 1 - / 100) * air for copper layers

(2) IJK = dielectric for dielectric layers

air and hence the second term can be neglected in (1) above

For the case of warpage, is:

-- Co-efficient of thermal expansion

-- Young’s modulus of elasticity

Cell IJ on stratum K has effective material

properties IJK

At the end of Stage 2, we have the effective material properties for each cell (MN cells)

in each stratum (P stratums)

1 <= I <= M

1 <= J <= N

1 <= K <= P

…

Side view of the PWB with “effective” grid elements across

the stratums

thickness

12

View of Analysis Building Block systemChopped (e.g. 4X4 grid) PWB Material properties

13

View of Analysis Building Block systemPWB Stackup Material properties

14

View of Solution Method ModelLayered shell mesh Geometric constraints

all 6 degrees of freedom locked at midpoint – boundary condition

Currently this model is tool-specific (ANSYS).

Future possibility of AP209-based implementation exists.

15

Contents

Design-Analysis Interface within a Multi-Representation Engineering Framework

Experimental Verification using Temperature-Dependent Shadow Moiré

Initial Results and Future Development

>>

16

Principles of Shadow Moiré

WhiteLight In

Diffusely ScatteredLight Out

Grating

Shadow Grating Sample

Example Fringe Intensity Images

VideoCamera

17

Specifications

Specifications• Sample Size: up to 400 x 400 mm

• Vertical Resolution: ± 1 µm

• Lateral Resolution: 640 x 480 pixels

• Temperature Range: -55 C to 300 C (continuous), 350 C peak

• Time per Measurement: 1 second (data acquisition), 2-10 seconds total

Shadow Moiré Verification - TherMoiré®

18

Design 1 Video Image

Design 1 High ResolutionShadow Moiré Phase Image

Shadow Moiré Data

19

25 C Absolute Coplanarity = 261 mils 150 C Absolute Coplanarity = 234 mils

Coplanarity = 25.4 mils 150 C relative to 25 C Coplanarity = 7.4 mils

20

-100

-50

0

50

100

150

200

Tem

per

atu

re (

C)

0

5

10

15

20

25

Model Exp't

Sca

le (

mil

s)

-50 C

21

-100

-50

0

50

100

150

200

Tem

per

atu

re (

C)

0

5

10

15

20

25

Model Exp't

Sca

le (

mil

s)

-25 C

22

-100

-50

0

50

100

150

200

Te

mp

era

ture

(C

)

0

5

10

15

20

25

Model Exp't

Sca

le (

mil

s)

0 C

23

-100

-50

0

50

100

150

200

Te

mp

era

ture

(C

)

25 C

24

-100

-50

0

50

100

150

200

Te

mp

era

ture

(C

)

0

5

10

15

20

25

Model Exp't

Sca

le (

mil

s)

50 C

25

-100

-50

0

50

100

150

200

Te

mp

era

ture

(C

)

0

5

10

15

20

25

Model Exp't

Sca

le (

mil

s)

75 C

26

-100

-50

0

50

100

150

200

Te

mp

era

ture

(C

)

0

5

10

15

20

25

Model Exp't

Sca

le (

mil

s)

100 C

27

-100

-50

0

50

100

150

200

Te

mp

era

ture

(C

)

0

5

10

15

20

25

Model Exp't

Sca

le (

mil

s)

125 C

28

-100

-50

0

50

100

150

200

Te

mp

era

ture

(C

)

0

5

10

15

20

25

Model Exp't

Sca

le (

mil

s)

150 C

29

Future DevelopmentsCurrent Status

Generated Warpage Analysis Model from PWB Design Data using AP210-based Engineering Framework

Compared Results with Temperature-Dependent Shadow Moiré Experiments

Future Developments (Analysis) Level of Idealization – Grid Dimensions, Vias,… Controlled Meshing (non-tool specific) Display Options

Future Developments (Validation) Initial Conditions and Panelization Boundary Conditions and Reference Plane Temperature Uniformity and Sample Variation

30

Acknowledgements Georgia Institute of Technology

– Robert Fulton– Injoong Kim– Miyako Wilson

LKSoftWare Gmbh– Viktoras Kovaliovas– Kasparus Rudokas– Tomas Baltramaitas

Rockwell Collins, Inc.– Michael J. Benda– David D. Sullivan– William W. Bauer– Mark H. Carlson– Floyd D. Fischer

PDES Inc.Electromechanical Pilot team

– Greg Smith (Boeing)– Craig Lanning (Northrup Grumman)– Steve Waterbury (NASA)

* Certain commercial equipment, instruments, or materials are identified in this paper in order to specify the experimental procedure adequately   Such identification is not intended to imply recommendation or endorsement by the National Institute of Standards and Technology, nor is it intended to imply that the materials or equipment identified are necessarily the best available for the purpose.