| 摘要 |
PROBLEM TO BE SOLVED: To reduce a leak current by reducing contamination of metal forming the polymetal gate of a MISFET. SOLUTION: A cap insulation film 10a, a W film 9c and a WN film 9b among polycrystal silicon film 9a, WN film 9b, W film 9c and gap insulation film 10a deposited on a gate insulation film 8 on a p-type well 3 (semiconductor substrate) are etched, the polycrystal silicon film 9a as the under layer is over- etched, side wall films SW are formed to the side walls of these films, and the polycrystal silicon film 9a is etched using the side wall film SW as the mask. Thereafter, a light oxide film 11a is formed to the side wall of the polycrystal silicon film 9a by conducting heat treatment in the oxidation atmosphere. As a result, contamination on the gate insulation film 8 by tungsten W and its oxide can be reduced and these substances are diffused into the semiconductor substrate (p type well 3) to prevent increase of a leak current. |
