A NEW POSITIVE DUV PHOTORESIST OPTIMIZED FOR 0.25-MU-M ISOLATED LINES

This paper reports on the Shipley/IBM developed UV4 positive DUV photo resist, which is particularly suitable for gate array applications. Th is resist shows greater than or equal to 1.4 mu-m DOF for 0.25 isolate d lines and similar to 20% exposure latitude. The UV4 photoresist has been designed to have relatively high developer selectivity (similar t o 8) and an R(max) of 3100 Angstrom/s. In this case, we have opted for a lower developer selectivity and R(max) than those of UVIIHS photore sist. The UV4 photoresist also shows good photospeed, less than or equ al to 30 mJ/cm(2), excellent postexposure delay stability, greater tha n or equal to 1 hour at 0.25 mu m, and better etch resistance than UVI IHS resist.