Dongjin Semichem is developing two new EUV photoresists, one inorganic and another dry.
The company was developing the inorganic EUV PR and dry EUV PR with a major customer, sources said.
Last year, the company already launched an organic EUV PR.
The new ones are being developed for application in more advanced chip process nodes.
Photoresists, or PR, are used during the lithography process when the semiconductor circuit is drawn on the wafer.
The PR is deposited on the wafer first, then a pattern is shot through light. The PR reacts chemically and the pattern is formed on the wafer.
Companies are working on developing PR that can be applied during the EUV process, which is being used more and more for advanced chip production.
EUV, or extreme ultraviolet, has up to 14 times the energy in its light compared to ArF.
At the same time, it has fewer photons, and these two things make it more prone to shot noise.
So the EUV PR needs to react chemically even with exposure to fewer photons.
The more likely technology to be widely adopted is a polymer (organic) EUV PR, a format already used in ArF.
It is a chemically amplified resist that increases the throughput of the lithography.
This type of PR is made by JSR, Shin-Etsu Chemical, TOK, and other Japanese companies.
Dongjin Semichem has also developed it and has been supplying it to a customer for their DRAM production.
But organic EUV PR is difficult to apply for finer circuit patterns. This is why companies are attempting to develop metal-based, inorganic EUV PR.
Inpria, a subsidiary of JSR, and Lam Research are leading this sector. In the case of Lam Research, it is developing a dry EUV PR __ which also uses inorganic material but is deposited as chemical vapor on the wafer, unlike the conventional spin coating method used.
Inorganic materials have smaller molecules and can absorb more photons compared to organic materials.
