Patent ID: 6342442
Filing Date: 2002-01-29
Classification: B23K,H01L

Abstract:
A method for bonding parts together, the method comprising the steps of:(a) applying at least a first chemical element layer of an intermetallic compound to a first part; (b) applying at least a second chemical element layer of the intermetallic compound to a second part, wherein one of the at least first and second element layers comprises a binary solder mixture which melts at a first melting temperature; (c) placing the second part on the first part so that the chemical element layers contact each other; (d) heating the parts from a storage temperature to a bonding temperature which is slightly above the first melting temperature that melts the binary solder mixture into a liquid mixture having a composition that varies with time during heating due to the formation of the intermetallic compound therein by progressive incorporation of the other one of the first and second chemical element layers into the mixture, the first melting temperature of the liquid mixture increasing with time as the composition changes until the melting temperature of the liquid mixture is about equal to the bonding temperature thereby soldifying the liquid mixture into a bond; and (e) holding the parts at a holding temperature which is higher than the storage temperature to maintain diffusion of the other one of the first and second chemical element layers into the bond thereby forming a quantity of the intermetallic compound in the bond which raises the melting temperature of the bond to a desired usage temperature that is substantially above the first melting temperature.