Critical Insights in the Application of Convection and Pressure Curing in Eliminating DAF Voids
Bryan Christian S. Bacquian *
New Product Development and Introduction, STMicroelectronics, Inc., Calamba City, Laguna, 4027, Philippines.
Rennier Rodriguez
New Product Development and Introduction, STMicroelectronics, Inc., Calamba City, Laguna, 4027, Philippines.
Edwin M. Graycochea
New Product Development and Introduction, STMicroelectronics, Inc., Calamba City, Laguna, 4027, Philippines.
*Author to whom correspondence should be addressed.
Abstract
The absent of reliable production controls for Die Attach Film (DAF) voids detection allowed defect escapee for Ball Grid Array (BGA) devices using non-conductive film material leading to gross assembly rejection and customer complaints. This paper presents the evaluation of pressure curing as an alternative to the convection curing in die attach process with additional capability to eliminate the DAF voids on non-conductive films. Through Analysis of Variance (ANOVA) analysis, green peeling test, Scanning Acoustic Microscope (SAM), cross section analysis and reliability test performed between samples arrives to the conclusion that pressure oven has a significant impact in die shear strength improvement and DAF voids elimination with positive response in reliability requirement. The result of the study improves the assembly flow and production control of BGA devices through the transition of convection to pressure curing technology.
Keywords: BGA, convection curing, pressure oven, DAF voids, process improvement.