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I have this question long in my mind: How to develop EUV photoresists without an EUV machine?
For typical material development, the same or similar equipment to industry standard are essential to validate performances. However, it's almost impossible to have an in-house EUV machine for EUV photoresists development due to the extreme high cost (or maybe I'm wrong). And because the wavelength of EUV is so different to immersion DUV, so immersion DUV cannot be used for examination. Is there a cheaper EUV prototype for this purpose?
Given there are inspection tools that use EUV light I wouldn't think it is too hard for a small lab or uni to make an EUV light source for testing the PR's chemistry. As for testing on an actual tool to see how actual patterns develop in real use cases; my guess is these supplier work with ASML, IMEC, and IBM labs. I think a while ago I also saw that TSMC was leasing out EUV stepper time on their tools for exactly this purpose. It would also not surprise me if the resist is compelling, the big three's CR/pathfinding arms would have no problem bringing it inside their fabs for testing and further refinement.
Building full scale EUV machine is difficult，however just building a simple EUV light source only for lab use isn't that difficult. Otherwise it will be a chicken or egg question，how do you build EUV machine if you have no EUV photoresist to test on？
I remember the news that after getting several dozens of EUV machines, tsmc has the luxury to lend some tool time for photoresist vendors. I was just thinking it would be difficult to test EUV photoresist at vendor sites at the beginning of EUV adaption. Nice to know it's not that difficult to have a simple EUV light source in lab.
I have this question long in my mind: How to develop EUV photoresists without an EUV machine?
For typical material development, the same or similar equipment to industry standard are essential to validate performances. However, it's almost impossible to have an in-house EUV machine for EUV photoresists development due to the extreme high cost (or maybe I'm wrong). And because the wavelength of EUV is so different to immersion DUV, so immersion DUV cannot be used for examination. Is there a cheaper EUV prototype for this purpose?
I believe Lawrence Berkeley Labs has actinic sources and uses various transmissive masks with narrow-field optics to evaluate resists, and other labs can probably do the same thing. The method was developed 30 years ago in the early investigations of EUV.
I have been working @ imec in the lithography group. Typically resist development starts on so-called small-field litho machines at sites like imec. These machines have a much smaller projection field than production machines but can already be used for resist development. Sometimes these machine are not even real projection systems but just print interference patterns like lines and spaces or array of holes by using a number of coherent beams focusing with a certain on a spot on the wafer.
Later on typically ASML installs a prototype tool @ imec where development than can continue on normal field size but on a tool not ready yet for production.
