INDIANA 
UNIVERSITY 
PURDUE 
UNIVERSITY 
INDIANAPOLIS

Computational Mechanics 
LABORATORY (CML)

723 West Michigan Street, SL 138  
Indianapolis, IN 46202-5132  

The general trends for microelectronics products have been characterized as high speed, high I/O, small profile, and high reliability. Among all the emerging technologies in electronic packaging, ball grid arrays(BGA) are considered as one of the most promising package. Moreover, due to complexity of geometry, predicting and understanding factors affecting life cycles of the joints of these components are of major concern.

 

Research at the Computational Mechanics Laboratory involves the fatigue life prediction of solder joints in BGA with the use of Finite Element Analysis (FEA). Two- and three-dimensional finite element models of BGA are constructed and analyzed under the thermal loads. The stress and strain results of different models are compared. The slice model of the BGA assembly along the diagonal of the structure, with appropriate boundary conditions, is proved to be able to produce results of comparable accuracy, with computationally efficiency. 

 

On the right is the finite element mesh constructed to represent 1/8th of a Ball Grid Array (BGA). Symmetry surfaces are assumed at the chip center-line and at the diagonal lines, which enabled the use of a 1/8th model instead of a complete model.

 

 

 

 

 

On the left is the contour of creep strain for a ball solder joint in BGA.