Warpage effect on breakdown voltage of DRAM device

As an oxidation resistant layer, silicon nitride film has been widely used in semiconductor processes. Normally, silicon nitride deposition induces strong tensile stress on the silicon wafer. This stress also contributes to the wafer warpage. In order to investigate the relationship between this phenomenon and electrical properties of device, we prepared silicon nitride coated wafers with different film thickness. After the silicon nitride deposition on both sides of wafers, we stripped full of the film or half of the film on the backside surface. For each and every wafer, the degree of warpage and the electrical characteristics were measured. In this paper, we reported the warpage trend according to the silicon nitride film thickness and to the area of nitride stripped backside surface. Besides, we observed breakdown voltage difference depending on the degree of warpage.