Enhancing fracture strength of thinned silicon dies by a hybrid micromachining method

The fracture strength of silicon wafers is crucial in determining the manufacturing yield, operational reliability and device performance of semiconductor components. Many researches have shown the surface finishing and stress release treatments such as wet etching, dry (plasma) etching, polishing, etc., can effectively improve the fracture strength of thinned silicon dies. In this paper, a novel hybrid micromachining method that integrates super-precision grinding process, backside rough finish etching, and backside metal deposition process, is studied with experimental investigation with an aim to improve the fracture strength of thinned silicon dies. The experimental results are shown to enhance the fracture strength by approximately 150% higher than the conventional grinding process with this novel method. In this way the semiconductor manufacturers have the benefits of retaining the mechanical performance as well as electrical or thermal performance of thinned silicon dies with the backside metal processing.