Managing Epoxy Tailing in Die Attach thru Design of Experiment
Michael D. Capili *
STMicroelectronics Inc., Calamba Philippines LISP 2 Calamba City, Laguna 4027, Philippines.
*Author to whom correspondence should be addressed.
Abstract
Die attach epoxy dispensing is an automated factory environment that creates some special challenges. A robust production process begins with an understanding of the adhesives in their fluid state and which important parameters must be controlled. One of the most common problems encountered with adhesives in Die attach process is epoxy tailing. Tailing in this sense means the peak of the dispensed material falls away from the center of the dot when the nozzle finishes dispensing. Dispensing requirements, techniques, and equipment resulting from this experience are discussed. Guidelines for optimizing quality is given. In this research, epoxy-associated defects are eliminated by optimizing the Break tail parameter using the Design of Experiment (DOE) methodology. The DOE prediction profile result shows that the tailing parameters recommended is Broken tail delay: 200 ms and Break tail offset is 350 counts. This study is applicable for silver filled conductive adhesive epoxy with greater than 9K Viscosity and greater than 4 Thixotropic Index.
Keywords: Break tail parameter, die attach, epoxy, epoxy tailing.