Current Status of EUV Photoresists

The current status of EUV resists is reviewed based on performance studies of line edge roughness (LER), sensitivity, resolution and pattern transfer. A large variation in polymer molecular weight (2.9-33.5 K g/mol) is found to have little effect on LER. Dissolution properties such as unexposed film thickness loss (UFTL) are shown to have a large effect on LER. Increasing resist contrast and image contrast are shown to improve resist LER. Variation in base level within resists based on EUV-2D shows a clear trade-off between sensitivity and LER. Acid difusion can play an important role in determining LER. Resist resolution and image transfer capabilities are also discussed.