Photo-nanoimprint lithography combined with thermal treatment to improve resist pattern line-edge roughness

We prepared a standard resist pattern to evaluate critical-dimension atomic-force microscopy (CD-AFM) by photo-nanoimprint lithography using a trilayer resist system. Standard patterns require low line-edge roughness (LER), which is an important factor in the accuracy of high-precision CD-AFM. However, LER can easily be increased during the dry etching necessary in the trilayer resist process. The LER of final standard patterns was 2.5 nm (1 sigma), which was made using a mould of which the LER is 2.2 nm. We thermally treated the standard resist patterns to reduce the LER; the LER improved from 2.5 to 1.2 nm with the thermal treatment.