Poly(cyclohexyl 2-cyanoacrylate) (PCHCA), a positive tone electron beam resist, has both high sensitivity and high dry-etching durability. Therefore, PCHCA has been successfully used for the fabrication of conventional chromium photomasks using dry-etching. However, when PCHCA was applied to the phase-shift mask fabrication, cracks were observed in resist patterns on the SiO2 shifter layer. The cyclic-alkyl group of PCHCA enhances dry-etching durability but causes the cracks in resist patterns. On the other hand, the noncyclic group prevent cracks, but reduces dry-etching durability. However, the copolymer of cyclohexyl 2- cyanoacrylate and ethoxyethyl 2-cyanoacrylate was delineated on SiO2 without generating cracks and reducing dry-etching durability, with high sensitivity. Using this copolymer, the phase-shift masks having SiO2 shifters with vertical walls were fabricated by dry-etching process in short time.