EUV resist chemical gradient enhancement by UV flood exposure for improvement in EUV resist resolution, process control, roughness, sensitivity and stochastic defectivity

Abstract

Flood Exposure Assisted Chemical Gradient Enhancement Technology (FACET) is introduced for improvement in EUV resist resolution, process control, roughness, patterning failure and sensitivity. Experimental EUV exposure latitude was enhanced (~1.5 times) with FACET using the assist of UV flood exposure. The mechanism of the process window improvement by FACET is explained by non-linear resist coloring (enhancement of UV absorption) vs. EUV exposure dose to enhance acid image contrast during UV flood exposure. To balance chemical gradient enhancement and stochastic effects, Stochastic Aware Resist Formulation and Process optimizer (SARF-Pro) with a fast stochastic simulation model is created. SARF-Pro predicts stochastic patterning failure risks, and optimizes resist formulation and processes by putting emphasis on stochastic variation across patterns. Photosensitized Chemically Amplified ResistTM (PSCARTM) 2.0 with FACET and standard chemically amplified resist (CAR) optimized in SARF-Pro suggests that PSCAR 2.0 with FACET has the potential of better process window, roughness, sensitivity and, we hypothesize, reduced risk of stochastic defects compared with standard CAR.