Patent ID: 6206269
Filing Date: 2001-03-27
Classification: H01L,Y10T

Abstract:
A method of soldering a semiconductor chip to a substrate, the method comprising:coating the semiconductor chip with an adhesion layer consisting of a first material composition;covering the adhesion layer with a solderable layer consisting of a second material composition;covering said solderable layer with an antioxidation layer consisting of a third material composition;covering the antioxidation layer with a layer of gold-tin solder;placing the chip on a solderable surface of a capsule via said gold-tin solder;exposing said capsule and said chip to an inert environment to which a reducing gas is delivered, and subjecting said capsule and said chip to a pressure that is substantially beneath atmospheric pressure whilst heating the gold-tin alloy to a temperature above its melting temperature;increasing the gas pressure whilst the gold-tin solder is molten; andlowering the temperature when exceeding a predetermined gas pressure so that the gold-tin solder will solidify.