A new inorganic EUV resist with high-etch resistance

Abstract

Performance requirements for EUV resists will necessitate the development of entirely new resist platforms. As outlined in the ITRS, the new resists for EUVL must show high etch resistance (to enable pattern transfer using thinner films), improved LER and high sensitivity. A challenge in designing these new resists is the selection of molecular structures that will demonstrate superior characteristics in imaging and etch performance while maintaining minimal absorbance at EUV wavelengths. We have previously described the use of inorganic photoresists in 193 nm and e-beam lithography. These inorganic photoresists are made of HfO2 nanoparticles and have shown etch resistance that is 25 times higher than polymer resists. The high etch resistance of these materials allow the processing of very thin films (< 40 nm) and will push the resolution limits below 20 nm without pattern collapse. Additionally, the small size of the nanoparticles (< 5 nm) leads to low LER while the absorbance at EUV wavelengths is low. In this presentation we show that these inorganic resists can be applied to EUV lithography. We have successfully achieved high resolution patterning (<30 nm) with very high sensitivity and low LER.