OPTICAL ELEMENT HAVING ANTIREFLECTION STRUCTURE, AND METHOD FOR PRODUCING OPTICAL ELEMENT HAVING ANTIREFLECTION STRUCTURE

摘要

An obj ect is to provide a method for producing an optical element having an antireflection structure that allows an optical element having a highly precise antireflection structure without pattern dislocation over a large area to be produced repeatedly. A cylinder-shaped Cr mask having a diameter of 0.15 µm is formed at a pitch of 0.15 µm on a quartz glass substrate. The quartz glass substrate on which the cylinder-shaped Cr mask is formed is placed in a RF dry-etching apparatus and the surface of the quartz glass substrate is etched with CHF 3 + O 2 gas. Thus, a cone-shaped antireflection structure with a pitch of 0. 15 µm and a height of 0.15 µm is formed on the surface of the quartz glass substrate. An Ir-Rh alloy film having a thickness of 0.05 µm for protecting the surface is formed on the surface (pressing surface) of the quartz glass substrate provided with the cone-shaped antireflection structure to form a mold having an antireflection structure. An optical material (crown based borosilicate glass) to which a releasing agent containing fine particles of carbon (C) for mold release is applied is press-molded with the mold having an antireflection structure, and the press-molded optical material is released from the mold having an antireflection structure without cooling. After the press-molded optical material is cooled, the releasing agent is removed.