Phase-shift photomask manufacturing method and phase-shift photomask

Abstract

In a method of manufacturing a phase-shift photomask comprising the steps of preparing a substrate transparent to an exposure light having a wavelength λ and having a refraction factor n, forming, on the substrate, a pattern including a light-blocking portion blocking the light entering and a light transmission portion transmitting light, and etching the substrate on the transmission portion including a plurality of transmission sections so as to provide adjacent transmission sections, one having a recessed depth d1 and the other one having a recessed depth d2 so as to satisfy an equation of (d1−d2)=λ/2(n−1), the etching step comprises a first etching process of a selective dry-etching to the light transmission section of the substrate having the depth d1 so as to provide a predetermined depth D1 after the formation of the light-blocking portion, a second etching process of a wet-etching process to the transmission section having the depth d1 so as to provide a depth of λ/2(n−1), and a third etching process of a wet-etching to all the light transmission section having the depth d1 and the depth d2 so as to satisfy an equation of (d1−d2)=λ/2(n−1).

Dependencies are inferred from the claim text.