STRESS-IMPROVED FLIP-CHIP SEMICONDUCTOR DEVICE HAVING HALF-ETCHED LEADFRAME

摘要

A semiconductor device ( 100 ) with a metal bump ( 203 ) on each interior contact pad ( 202 ) has a metallic leadframe with lead segments ( 220 ) with the first surface ( 220 a) in one plane. The second surface ( 220 b) is castellated across the segment width in two planes so that regions of a first segment thickness ( 240 a) alternate with regions of a reduced (about 50%) second segment thickness ( 240 b); the first thickness regions are in the locations corresponding to the chip interior contact pads (half-etched leadframe). The second segment surface faces the chip so that each first thickness region aligns with the corresponding chip bump. The chip bumps are attached to the corresponding second segment surface using reflow metal. Dependent on the orientation of the attached half-etched segment, thermomechanical stress concentrations away shift from the solder joints into the leadframe metal, or shear stress may reduced.