Printed circuit boards (PCB’s) often warp when subjected to temperature changes, associated with either the manufacturing process or the usage. In order to reduce the warpage, waviness was introduced in the electric traces. Model PCB’s were manufactured and tested. The elastic stiffnesses of the PCB’s were determined using a coupled experimental-analytical vibration method, whereas coefficient of thermal expansions (CTE’s) and warpage were measured by placing strain-gage instrumented specimens in an environmental chamber and varying the temperature. Unit cell finite element (FE) analyses of PCB’s with both straight and wavy traces were performed to predict thermoelastic behavior. Both experimental tests and numerical analyses conclude that the PCB’s with wavy traces warped approximately 40% to 60% less than the PCB’s with straight traces.

Issue Section:
Research Paper
Keywords:
thermal expansion, printed circuit testing, printed circuit manufacture, finite element analysis, thermoelasticity, printed circuit design
Topics:
Finite element analysis, Printed circuit boards, Thermoelasticity, Warping, Temperature
1.
Ritchey
,
L. W.
,
2000
, “
PCB Routers and Routing Methods
,”
Printed Circuit Design
,
17
(
2
), pp.
26
–
29
.
2.
Gilleo
,
K.
,
Witt
,
M.
,
Blumel
,
D.
, and
Ongley
,
P.
,
1999
, “
Towards a Better Understanding of Underfill Encapsulation for Flip Chip Technology: Proposed Developments for the Future
,”
Microelectronics International
,
16
(
2
), pp.
39
–
43
.
3.
Zhang
,
S.
,
De Baets
,
J.
, and
Van Calster
,
A.
,
1999
, “
A Two-Layer High Density Printed Circuit Board and Its Reliability
,”
Microelectron. Reliab.
,
39
, pp.
1337
–
1341
.
4.
Chou
,
T.-W.
, and
Takahashi
,
K.
,
1987
, “
Nonlinear Elastic Behavior of Flexible Fiber Composites
,”
Composites
,
18
, pp.
24
–
34
.
5.
Kuo
,
C.-M.
,
Takahashi
,
K.
, and
Chou
,
T.-W.
,
1988
, “
Effect of Fiber Waviness on the Nonlinear Elastic Behavior of Flexible Composites
,”
J. Compos. Mater.
,
22
, pp.
1004
–
1025
.
6.
Highsmith, A. L., Davis, J. J., and Helms, K. L. E., 1992, “The Influence of Fiber Waviness on the Compressive Behavior of Unidirectional Continuous Fiber Composites,” Composites Materials: Testing and Design (Tenth Volume), ASTM STP 1120, Glen C. Grimes, ed., Philadelphia, PA, pp. 20–36.
7.
Hsiao
,
H. M.
, and
Daniel
,
I. M.
,
1996
, “
Elastic Properties of Composites with Fiber Waviness
,”
Composites
,
27
, pp.
931
–
941
.
8.
Grenestedt
,
J. L.
, and
Hutapea
,
P.
,
2003
, “
Influence of Electric Artwork on Thermomechanical Properties and Warpage of Printed Circuit Boards
,”
J. Appl. Phys.
,
94
(
1
), pp.
686
–
696
.
9.
Hutapea, P., and Grenestedt, J. L., 2004, “Tuning of Electric Artworks of Printed Circuit Boards to Reduce Warpage,” IEEE 9th International Symposium on Advanced Packaging Materials: Processes, Properties and Interfaces, Atlanta, Georgia.
10.
Designing Balanced Printed Circuit Boards, 1997, Merix Corporation, Forest Grove, Oregon.
11.
Krueger, S., Barry, D., and Payne, D., 2001, Breaking the CAM Bottleneck, Atomic29, Los Altos, California.
12.
Zweben, C., 2002, “Advances in Materials for Optoelectronic, Microelectronic and MOEMS/MEMS Packaging,” Proceedings of Eighteen Annual IEEE Semiconductor Thermal Measurement and Management Symposium, San Jose, California, pp. 30–34.
13.
Culbertson, E. C., 1995, “New Laminate Material for High Performance PCBs: Liquid Crystal Polymer Copper Clad Films,” Proceedings of the 1995 45th Electronic Components & Technology Conference, Las Vegas, Nevada, pp. 520–523.
14.
Grenestedt
,
J. L.
, and
Hutapea
,
P.
,
2002
, “
Using Waviness to Reduce Thermal Warpage of Printed Circuit Boards
,”
Appl. Phys. Lett.
,
81
(
21
), pp.
4079
–
4081
.
15.
Hutapea
,
P.
, and
Grenestedt
,
J. L.
,
2003
, “
Effect of Temperature on Elastic Properties of Woven Glass Epoxy Composites for Printed Circuit Board Applications
,”
J. Electron. Mater.
,
32
(
4
), pp.
221
–
227
.
16.
Taylor, R. E., 1998, Thermal Expansion of Solids, CINDAS Data Series on Material Properties Vol. I-4, Ho, C. Y., ed., ASM International.
17.
Vishay Measurements Group, 1993, Measurement of Thermal Expansion Coefficient Using Strain Gages, www.measurementsgroup.com, TN-513-1.
18.
Sottos
,
N. R.
,
Ockers
,
J. M.
, and
Swindeman
,
M.
,
1999
, “
Thermoelastic Properties of Plain Weave Composites for Multilayer Circuit Board Applications
,”
ASME J. Electron. Packag.
,
121
, pp.
37
–
43
.
Copyright © 2004
 by ASME
You do not currently have access to this content.