| 摘要 |
<P>PROBLEM TO BE SOLVED: To form a light-shielding layer with a high light shielding property on a stepped wall surface of a diffraction grating. <P>SOLUTION: A diffraction grating 2 including a plurality of step-like parts is formed with an Al<SB POS="POST">2</SB>O<SB POS="POST">3</SB>layer 4 on optical effective surfaces for transmitting light and an Al layer 3 on stepped wall surfaces as a light shielding layer. At first, an Al film is formed such that light is incident at normal incidence to the stepped wall surface and is incident at oblique incidence to the optical effective surface. After that, oxidation treatment is performed from a direction to be incident at normal incidence to the optical effective surface so that the Al on the optical effective surface is changed to Al<SB POS="POST">2</SB>O<SB POS="POST">3</SB>. The Al<SB POS="POST">2</SB>O<SB POS="POST">3</SB>layer 4 for transmitting light is formed on the optical effective surface, and the high-density Al layer 3 is left on the stepped wall surface so as to form the light shielding layer with high light shielding property. <P>COPYRIGHT: (C)2013,JPO&INPIT |
