A study of line edge roughness in chemically amplified resist for low energy electron-beam lithography

We investigated the line edge roughness (LER) of the resist pattern in a high sensitivity resist process using low energy e-beam lithography (LEEBL). In order to explain the experimental results, we have proposed a model considering the secondary electron (SE) yield and the diffusion of SE. The results of simulation based on the proposed model indicated the following: (1) in the case of 2 keV, acceptable acid distribution is generated due to the high SE yield and the SE diffusion. As a result, a high quality resist pattern could be obtained, even if the exposure dose is below 0.5 /spl mu/C/cm/sup 2/, and (2) in the case of 50 keV, the acid generated at the unexposed area due to the proximity effect make the LER larger. Our simulation indicated that the LER of the 2 keV exposure with 0.4 /spl mu/C/cm/sup 2/ is smaller than that of the 50 keV exposure with 2 /spl mu/C/cm/sup 2/ 2. From these results, we think that high sensitivity resist process at the exposure dose below 0.5 /spl mu/C/cm/sup 2/ can be achieved in LEEBL.