Achieving Less Than 1% Voiding in GaN Die Attach Processing
Download the Article!The die bonding, or die attach process, consists of attaching a die/chip to a substrate or package. This attachment can be performed with either eutectic solder or adhesive (epoxy). This article will discuss the eutectic (where the liquidus and solidus temperature are the same) solder die attach where the preform is an alloy comprising a mixture of two or more dissimilar metals. The preform is a flat sheet of material slightly smaller in area than the die. This preform is typically 25–50μm thick. It is placed between the die and substrate for subsequent melting to wet both the backside of the gold-coated die, and the gold surface of the package/substrate. In our evaluation, the AuSn preform was used with the exact ratio of 80% gold and 20% tin with a melting point of 278°C.
Download to read more...