Methods of stabilizing linewidths in photolithography for improving ASIC plant productivity

The two methods described are useful for stabilizing linewidths in photolithography without making any changes in existing processes and equipment. The methods can also be applied to the stabilization of line widths in 130-nm scale devices, which is currently an urgent need. 1) Controlling the thickness of LOCOS-SiN film can stabilize device isolation width. Also, adjusting the thickness of the resist film can standardize SiN film thickness conditions and thereby reduce deviations in linewidth that are caused by imprecise film thickness. 2) Optimizing the film thickness standard for gate oxidation film processing with a sufficient process capability can increase the range of allowable gate lengths, thereby improving process capability.