Super High Sensitivity Enhancement by Photo-Sensitized Chemically Amplified Resist (PS-CAR) Process

Over the past decade, the low intensity of extreme ultraviolet (EUV) light sources has been the most critical issue in the development of a promising, next–generation, high volume manufacturing (HVM) EUV lithography method. Specifically, enhancing the sensitivity of EUV resists to compensate for this low intensity is one of the most critical challenges for HVM implementations of EUV lithography. However, EUV light source power intensity remains one order less than the required value. Sensitivity enhancement of an EUV resist without any loss in other important properties such as resolution is inadequate to compensate for the low intensity of EUV sources in conventional EUV single exposure. Therefore, we propose a method for increasing the resist sensitivity considerably by combining the lithography of 1 EUV pattern exposure with a 2 UV flood exposure (PF combination lithography) and a photosensitized chemically amplified resist (PS-CAR). This method achieves high sensitivity enhancement not only with EUV but also with electron-beam, ArF, and other types of pattern exposure. Thus, a sensitivity increase of more than one order without any loss in space resolution was achieved compared with conventional lithography by PF combination lithography of 1 EB pattern exposure with 2 UV flood exposure and PS-CAR. Differences between EB and EUV resists include energy absorption processes, and the resist sensitivities of EUV can be predicted easily from the exposure results of EB lithography. Therefore, the reaction mechanism of EUV pattern exposure–UV flood exposure combination lithography of PS-CAR can be essentially evaluated with EB pattern exposure–UV flood exposure combination lithography of PS-CAR. Keyword: Photosensitized Chemically Amplified Resist (PS-CAR), Sensitivity Enhancement, Pattern and Flood Exposure, Combination Lithography, EUV, EB

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