Blazed holographic grating, method for producing the same and replica grating

摘要

A substrate is subjected to holographic exposure to a sinusoidal or half-sinusoidal resist pattern corresponding to grating groove thereon. Thereafter, the substrate and the resist pattern are subjected to a first etching step at which they are irradiated with an ion beam obliquely at an angle that is identical to the blaze angle in the presence of CF₄ as an etching gas, whereby they are cut until the height of the resist is about 1/3 of the initial value. Thereafter, the substrate is subjected to a second etching step at which the substrate is irradiated with an ion beam in the direction corresponding to the bisector of the vertex in the presence of a mixture of CF₄ and O₂ as an etching gas, whereby the substrate is cut until the resist disappears completely to an extent such that some overetching occurs.