Hello all
I have an oxide surface whom I want to pattern and later need metal deposition on the patterned surface (lift-off). I have used bilayer method i.e LOR (LOR 3B) and PPR (S1813) coating and then metallization - for lift-off but my oxide got removed from many parts on the sample - reason being, low quality oxide. Due to some technical issues, we cannot go for a higher quality oxide and this oxide can well serve our purpose. Secondly, it might be due to adhesion- so I used a trilayer method, HMDS (vapors)/LOR/PPR. This time on two-three occasions, I got proper results. However, after that, the oxide that was patterned had to be etched (wet etching) and it got etched at certain points on the sample and didn't etch at some points, all randomly. But the patterns have been good and the oxide doesn't remove after using the trilayer method.
Has anyone faced similar issue or anyone could comment on it. Can all three layers be used together, if yes, what recipe would you recommend.
Hi
Why do you use of LOR ?
if your metal is thin you can eliminate LOR, only HMDS +1813 is enough
if you need thick metal, first you can etch your oxide with thin resist and after removing resist again doing lithography with thick oxide and doing metalization
Hi @Mohsen
I am using LOR to get a good lift-off - that was the main idea. As of now, my minimum feature size is 4 um but I plan to goto nm regime in future.
Yes, my metal layer is 120 nm to 150 nm, and I think that can be counted as a thin layer. So, I will look into HMDS+PPR bilayer resist coating (HMDS vapor coated + PPR spin coating). Thank you for your suggestions.
So you suggest that for thick metal layers, oxide etch with just HMDS+PPR and then lithography level with HMDS+LOR+PPR. Am I getting it right?
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