Fabrication of Si-based nanoimprint stamps with sub-20 nm features

We present two alternative methods for fabrication of nanoimprint lithography stamps in SiO2 with sub-20 nm features: (a) optimized electron beam lithography (EBL) and lift-off patterning of a 15-nm thick Cr mask, and (b) aerosol deposition of W particles in the 20-nm size range. In both cases, the pattern transfer into SiO2 was performed using reactive ion etching (RIE) with CHF3 as etch gas. In the first approach, we used a double layer resist system (PMMA/ZEP 520A7 positive resists) for the EBL exposure. Resist thickness, exposure dose and development time were optimized to obtain 15-20 nm features after Cr lift-off. In the second approach, we used size selected W aerosol particles as etch masks during etching of SiO2. Both methods of stamp fabrication are compared and discussed. (C) 2002 Published by Elsevier Science B.V.