Quantitative analysis of EUV resist outgassing - art. no. 692345

Extreme ultraviolet (EUV) resist outgassing is viewed as one of the main factors to be considered in the research and development of EUV resists. The release of resist by outgassing in a high-vacuum EUV exposure tool system can mean contaminated optics which in effect causes a decrease in EUV energy reaching the wafer surface. An energy decrease could translate to lower throughputs and lesser productivity. In this paper, the quantification of resist outgassing upon EUV exposure is discussed. Special attention is given to the variation of resist outgassing quantification between evaluation tools of different beam intensities using the pressure rise method. Besides the commonly used resist outgassing rate calculation, the utilization of the resist outgassing amount as basis for comparison is proposed. Three types of resists were analyzed in two resist outgassing evaluation tools of different EUV beam intensities. As a result, resist outgassing rate was found to vary 19 to 109 times between evaluation tools. In contrast, resist outgassing amount was found to vary I to 2 times between evaluation tools. From these results, it is proposed that resist outgassing evaluations be performed using resist outgassing amount.