The optimization of photoresist profile for sub-90nm technology

In this study, we have investigated the profile of ArF photo-resist patterns in order to optimize the next generation photo process of trench layer and improve their profile. In terms of resolution, PR (Photo Resist) for 193 nm (ArF) has better quality than that of 248 nm (KrF). However, there found some problems such as LER (Line Edge Roughness), top loss, sloped side wall, footing and standing wave in the aspect of PR profile. Thus, we observed the ArF PR profile which has different process condition like TBARC, SOB (Soft Bake) and PEB (Post Exposure Bake) for the profile optimization. As a result, the enhancement of sloped side wall, footing, and rounded top is obtained when the SOB and PEB temperature are tuned under the optimized condition of T_BARC (BARC thickness), and T_PR (PR thickness). Finally, we could set up the optimized process condition according to the result described above.