Development of closed-type EUV pellicle

摘要

In this study, we fabricated a closed type EUV pellicle without any gaps by using the mask adhesive, forming the vent holes in the Si border part and putting the sufficiently wide area filters on the top side of Si border. Ventilation performance of closed EUV pellicle was examined during pumping and ventilation condition. As the result, we found that the closed EUV pellicle has enough ventilation performance under the practical pumping down condition. Furthermore, as for EUV pellicle, contamination growth on mask surface during EUV exposure should be suppressed. We fabricated EUV pellicle with coated adhesive as the mask adhesive to suppress the outgas generation which causes the contamination on mask during EUV exposure. EUV irradiation was performed to the base plate which has similar component of the EUV mask surface inside the pellicle space. Contamination growth was not observed for the sample with coated adhesive, but observed for the sample with general adhesive as mask adhesive. Coated adhesives for mask adhesive of EUV pellicle, which keep the adhesive properties, will be suitable for fixing method to suppress the mask contamination during EUV exposure.