The trim process with organic BARC to fabricate sub-90 nm gate was developed with ArF lithography.
This trim process is not required extra hard mask layer which we usually use to overcome weak etching
resistance of ArF photoresist. BARC etching step has been chosen as the best layer to apply trim
process. We understood that the mix ratio of Cl2/O2 is the key process parameter to control etching bias.
Also we observed that ID bias by changing BARC etching time. PCM and TEM inspection results proved
that excellent transistor performance without any issues. LER improvement was observed by trim process
application. and it helps to improve device performance. This organic BARC based trim process showed
very promising results for sub-90 nm gate patterning.