Study on the multi layers for EUV pellicle

Due to the challenges to meet the transmittance requirements with Si related multi layers for EUV pellicle, many deposition method are tested to evolve the EUV transmittance. For the mass production using EUV lithography, it is expected that high transmittance EUV pellicles will be needed to improve productivity without particle induced yield drop. However, the structure of current EUV pellicle is too thin to handle it. Also, too thin layer cannot protect core layer such as p-Si during the EUV lithography, chemically. Thus, the new layers and materials are needed to achieve high transmittance of EUV and the physical strength. FINE SEMITECH CORP. ("FST"), started to develop new method for EUV pellicle capping layers. First of all, following simulation data were the EUV transmittance trend of SiN layer by according to Si/N ratio. From these simulation data, a simple calculation was formed to predict the EUV transmittance of SiN layer by measuring the atomic ratio. Also, we showed some experimental data of new-SiN layers. A thinner new-SiN layer was adoptable as protective layer with high EUV transmittance for the core layer of EUV pellicle from the results.