Polymer ablation at typical EUV doses

[Fred Chen]

I was surprised to come across these papers while looking up EUV-induced plasma.

https://www.academia.edu/download/78708852/j.elspec.2010.12.03020220114-10990-17pn92i.pdf

https://bibliotekanauki.pl/articles/1539081.pdf

https://www.researchgate.net/publication/225661488_Ablation_and_surface_modifications_of_PMMA_using_a_laser-plasma_EUV_source

Basically, doses of less than 10 mJ/cm2 up to 60 mJ/cm2 in the EUV spectrum were sufficient for polymer ablation to occur. I expect this can aggravate or at least complicate the occurrence of stochastic defects. In any case, the observed thinning of EUV resist after exposure is also consistent.

It looks bad for High-NA with its ultrathin resists and higher doses (to make up less absorption).

 

[hasty2333]

This is always the weakness of polymer-based resists; otherwise, why has the MOx resist from Inpria received so much attention (both in publications and court)? Metal powder. Its etch selectivity endows it with sufficient thickness until plasma etch.

 

[Fred Chen]

This is always the weakness of polymer-based resists; otherwise, why has the MOx resist from Inpria received so much attention (both in publications and court)? Metal powder. Its etch selectivity endows it with sufficient thickness until plasma etch.

It also has some thinning ("compression") due to low energy electrons https://pubs.acs.org/doi/10.1021/acsami.9b19004?ref=pdf. It is actually partially organic.