Description: We investigate some of the mechanical design factors of wafers and the effect on strength. Thin, solid, pre-stressed films are proposed as a means to improve the bulk mechanical properties of a wafer. Three-point bending was used to evaluate the laser scribe density and chemical processing effect on wafer strength. Drop and strike tests were employed to investigate the edge bevel profile effect on the mechanical properties of the wafer. To characterize the effect of thin films on strength, one-micron ceramic films were deposited on wafers using PECVD. Coated samples were prepared by cleaving and were tested using four-point bending. Film adhesion was characterized by notched four-point bending. RBS and FTIR were used to obtain film chemistry, and nanoindentation was used to investigate thin film mechanical properties. A stress measurement gauge characterized residual film stress. Mechanical properties of the wafers correlated to the residual stress in the film.
Date: August 2002
Creator: Yoder, Karl J.