NEGATIVE I-LINE PHOTORESIST FOR 0.5-MU-M AND BEYOND

In this article we will discuss a new high-resolution aqueous base developable negative tone i-line photoresist system that has demonstrated subhalf-micron resolution with commerically available i-line exposure systems. The photoresist system consists of a novolak resin, an aminoplast crosslinker, triphenyl sulfonium triflate as the photoacid generator, and 9-anthracene methanol, a commercially available aromatic energy transfer compound. Using statistical experimental design, data will be presented showing the experimentation required to optimize the formulation and the process in 2.38% TMAH developer (0.263 N). We will report linewidth, dose, and focus latitude data, energy transfer compound effects on contrast, background dissolution along with linewidth tolerance to changes in postexposure bake temperature. Additionally, we will briefly discuss initial phase-shift mask work that is currently in progress.