Backside Preparation And Metallization of Silicon Wafers for Die-Bonding
Original Publication Date: 1986-Jul-01
Included in the Prior Art Database: 2005-Mar-09
The backside of a semiconductor chip is coated with chromium or titanium followed by a layer of nickel or copper with sufficient co-deposition and then a layer of gold, so as to serve as a solderable surface for mounting the semiconductor chip to a module. The module has a coating of tin on its surface so that the metallized backside of the semiconductor chip can be set upon the tin layer and the assembly heated in a furnace to reflow the tin and form a solder bond with the composite metal coated on the backside of the chip. The structure and process has the advantage of not requiring a mechanical scrubbing action to in bonding between the tin and the composite metal layers on the backside of the chip.