For below Hp22nm generation, Hard-mask strategy is one of the key issues to achieve the good balance for
Lithography and Etching performance.
The thickness of resist should be thicker enough to obtain the etching margin for the substrate etching. However,
the thickness of photo resist (PR) needs to be thinner to obtain the good pattern collapse margin and resolution. In
order to solve this tread-off, the spin-on hard mask (HM) technology can be applied.
On the other hand, the ultra thin organic Underlayer (UL) being combined with the CVD-HM film stack is also
one of the processes for EUV lithography. In order to avoid the film loss of resist during UL open, the thickness of
UL must be thinner and the etch rate need to be faster. We studied the effect of UL design and thickness for the
EUV lithography performance.
For EUV lithography, the electron generation effect from UL is one of the key factors to improve the patterning
performance of resist. In this paper, we studied the suitable functional group for the Silicon containing HM(Si-HM)
for multilayer process and Org.-UL, which has high potential to generate 2nd electron and enhance the resist
performance, and discuss the material design and performance.