EUV Pellicle and Photoresist Development Accelerating
The author is an analyst of NH Investment & Securities. He can be reached at hwdoh@nhqv.com. -- Ed.
EUV pellicle and photoresist development is accelerating. Imec announced that it has succeeded in developing EUV pellicles for CNT materials. Inpria claimed that it will begin mass production of metal oxide photoresists. We expect EUV mass production yield to increase significantly in 2021.
Imec develops carbon nanotube EUV pellicles
EUV-related materials and equipment are being improved. Belgian research institute Imec claims to have developed a next-generation EUV pellicle (a component that protects the mask from contaminants) made of carbon nanotube (CNT) material. EUV has a wavelength of 13.5nm, so it is absorbed by most materials and therefore has low transmission. It has been impossible to manufacture pellicles with the materials currently available.
Imec developed pellicle with the new material CNT and recorded EUV transmission of 97%. Recently, many domestic and foreign players are developing EUV pellicles with new materials such as silicon, CNT, and silicon carbide. From 2H21, pellicles will be installed in EUV equipment, and EUV mass production is expected to rise. Domestic companies developing related equipment include S&S Tech and FST.
Inpria mass-produces metal oxide photoresist
Inpria, a US material startup, announced that it will begin mass production of metal oxide (MOx) photoresist for EUV. EUV illumination sources produce 14 times fewer photons than ArF. When using conventional chemical amplified resist (CAR) photoresist, various problems, such as stochastics defects due to photon shot noise or light blur, can occur. Developing a 20mJ/cm2 resist or using a metal oxide photoresist solves the problem.
Metal oxide photoresist can form finer patterns compared to existing products. It absorbs EUV light 4~5 times more efficiently, resulting in low blur. Design flexibility can be increased by improving etch selectivity. With this product, Inpria succeeded in 24nm pitch patterning using ASML NXE 3300~3400 lithography equipment. Inpria has been developing metal oxide photoresists since 2008. The firm has been cooperating with JSR in Japan for manufacturing processes and TOK in Japan for materials, developer, etc. Samsung Electronics and SK Hynix both invested in Inpria in 2020.