A Study of the Effect of Back Grind Wheels on Wafer Edge Chippings and Die Strength

Abstract

The drive for thinner package architecture is already becoming a necessity. There were a need of thinner Integrated Circuit or IC in order to fit in to thinner applications like mobile phones. One of the major semiconductor process that enables miniaturization was wafer back grinding. The process involves wafer thinning to a required thickness with the use of back grinding wheels that serve as the abrasive material. The paper will discuss the effect of back grind input parameters like step grinding and wheel grit size to its output characteristics like total thickness variation, edge chippings and die strength. Total thickness variation will define if the new wheel will not affect the variation with the wafer. On the other hand, edge chippings and die strength will define the reliability of the die on different conditions of the package. Lastly, these 3 characteristics will establish the manufacturability of the process as it will eliminate the probability of wafer breakage.