Quantitative measurement of EUV resist outgassing

The Mo/Si multilayer mirrors used for extreme ultraviolet (EUV) lithography can become contaminated during exposure in the presence of some hydrocarbons [1-3]. Because this leads to a loss in the reflectivity of the optics and throughput of the exposure tools, it needs to be avoided. Since photoresists are known to outgas during exposure to EUV radiation in a vacuum environment, the careful choice of materials is important to preserving the EUV optics. Work therefore has been performed to measure the species and quantities of molecules that outgas from EUV resists when exposed to EUV radiation [4-7].