Effect of develop time on process windows in sub-half micron optical lithography

The effect of develop time (DT) on process control of the sub-half-micron o ptical lithography step of a production CMOS process is examined. It is sho wn that develop times greater than those generally used increase the depth- of-focus (DOF), exposure latitude (EL), linearity, exposure margin and resi st sidewall angle, thereby improving the process capability. Results are gi ven for both practical experiment and simulation using PROLITH/2. The simul ation parameters used have been highly refined to give excellent correlatio n with experiment over a wide range of conditions.