A semiconductor packaging structure includes a copper heat-sink with a shim projection which provides a stress release structure. The heat-sink with the shim projection may be used in conjunction with a pedestal in order to further reduce the thermal stress produced from the mismatch of thermal properties between the copper heat-sink metal and the ceramic frame. The copper heat-sink with a shim projection may also be part of the semiconductor package along with a lead frame, the ceramic frame, a semiconductor device, a capacitor, a wire bond and a ceramic lid or an encapsulation. The copper heat-sink, the ceramic frame and the lead frame are all chosen to be cost effective, and chosen such that the packaging process for the semiconductor device is able to achieve a smaller size while maintaining high reliability, low cost, and suitability for volume manufacturing.