Patent ID: 6158645
Filing Date: 2000-12-12
Classification: B23K,H01L

Abstract:
A method of bonding a radiation plate to a back side of a plated die pad of a lead frame to which semiconductor chips are solder bonded, comprising the steps of:overlaying the radiation plate on the back side of the plated die pad;clamping the plated die pad and the radiation plate between first and second clamp members each of which has a knurled face formed on the clamp face thereof, the first clamp member engaging a surface of the plated die pad and having a knurled face with grooves only in a direction perpendicular to an ultrasonic waves applying direction; andapplying ultrasonic waves in a direction perpendicular to said grooves through at least one of the first and second clamp members to bond the back side of the plated die pad with the radiation plate while limiting scratch depth on the plate die pad to at least one of a maximum of 15 .mu.m and an average depth of 2.0 .mu.m.