Design, Experiment and Analysis of the Solder on Rubber (SOR) structure of WLCSP

Author

Yuan, Cadmus ; Zhang, G.Q. ; Huang, Ching-Shun ; Yu, Chun-Hui ; Yang, Chin-Cheng ; Yang, Wen-Kung ; Yew, Ming-Chih ; Han, Cheng Nan ; Chiang, Kou-Ning

Author_Institution

Dept. of Precision & Microsyst. Eng., Delft Univ. of Technol.

fYear

2006

fDate

24-26 April 2006

Firstpage

1

Lastpage

7

Abstract

A novel solder on rubber (SOR) structure of the advanced wafer level chip scaled packaging (WLCSP), having the capability of releasing the deformation energy which is caused by the CTE mismatch between the silicon chip and the substrate, is proposed herein. In the SOR structure, a metallic trace and solder pad would be formed on the rubber-based polymer, and a solder is attached onto the said pad. Moreover, a delamination layer is designed and fabricated between the metallic trace and the stress buffer layer (SBL), and the metal trace is also designed as curved shape to prevent the over-stretching of the trace. By the failure of the designed delamination layer, the SOR structure could theoretically release more energy than the conventional WLCSP structure. In this paper, the design concept of the SOR structure, experimental measurement of the adhesion strength of the delamination layer and the finite element (FE) analysis of the SOR structure are discussed

Keywords

chip scale packaging; polymers; solders; substrates; thermal expansion; coefficient of thermal expansion mismatch; deformation energy; delamination layer; finite element analysis; finite element method; metallic trace; nondestructive ball shearing test; rubber-based polymer; silicon chip; solder on rubber structure; solder pad; stress buffer layer; wafer level chip scaled packaging; Adhesives; Buffer layers; Chip scale packaging; Delamination; Polymers; Rubber; Shape; Silicon; Stress; Wafer scale integration; Solder on Rubber (SOR); Wafer level chip scaled packaging (WLCSP); finite element method; non-destructive ball shearing test;

fLanguage

English

Publisher

ieee

Conference_Titel

Thermal, Mechanical and Multiphysics Simulation and Experiments in Micro-Electronics and Micro-Systems, 2006. EuroSime 2006. 7th International Conference on

Conference_Location

Como

Print_ISBN

1-4244-0275-1

Type

conf

DOI

10.1109/ESIME.2006.1643969

Filename

1643969