We have developed an improved AFM-based technique to measure intrinsic material roughness (IMR) after base development. We have found that similar results can be obtained by measuring the film roughness with a fixed develop time and variable dose to that of the previously reported interrupted development method, and thus a simple contrast curve can yield information on the innate material roughness of the exposed resists. It was found that the IMR is dependent on the PAG and the polymer employed in the resist. The IMR of the resist is also strongly dependent on the bake conditions, with increasing IMR at higher bake temperatures. Several PAGs have been identified that result in significantly lower material roughness and thus the potential for significantly reduced line width roughness in resist imaging. Evidence is presented that PAG segregation during the bake steps is responsible for increased IMR in exposed resists, presumably by increasing the dissolution rate inhomogeneity on a nano-scale level. It is also shown that the effects of PAG segregation can be mitigated by the choice of PAG and polymer for the resist.

Date Published: 11 April 2007
PDF: 10 pages
Proc. SPIE 6519, Advances in Resist Materials and Processing Technology XXIV, 65190X (11 April 2007); doi: 10.1117/12.713892

Published in SPIE Proceedings Vol. 6519:
Advances in Resist Materials and Processing Technology XXIV
Qinghuang Lin, Editor(s)