Impacts of back-grinding process parameters on the strength of thinned silicon wafer

In order to achieve the packages with much higher performance, more I/Os, lower profile and lighter weight, the thickness of silicon wafer has been decreased dramatically in recent years, but which degrades the strength of thinned wafer. In this paper, three-point bending test was adopted to evaluate the thinned wafer fracture strength, and the impacts of back-grinding process parameters on the wafer fracture strength were addressed. Results show the trend of an increase in wafer strength with an increase in grinding wheel rotational speed and a decrease in grinding wheel feed rate. Also, it is found that the strength decreases progressively from the center of wafer to the edge for most wafer samples.