| 摘要 |
PROBLEM TO BE SOLVED: To provide a method of forming a diffraction grating by which the formed diffraction grating is more finely micronized. SOLUTION: In the method of forming the diffraction grating 40 in an optical wave guide layer 14 using a photomask 50, the photomask 50 in which a plurality of mask parts 52 having a cross-sectional shape so that the width w1 of a foot part end surface 54a is narrower than the width w2 of a head part end surface 56a are periodically arranged is formed on the optical wave guide layer 14 and after the optical wave guide layer 14 is etched using the photomask 50 as a mask, the upper surface 14a of the optical wave guide layer 14 is covered with a resin 70 and the foot part 54 is surrounded by the resin 70. The photomask 50 is removed to expose a region 14b corresponding to the foot part end surface 54a of the mask part 52 in the upper region 14a of the optical wave guide layer 14 from the resin 70 and next, the exposed region 14b of the upper surface 14a of the optical wave guide layer 14 is etched using the resin 70 as a mask and finally the resin 70 is removed from the upper surface 14a of the optical wave guide layer 14. COPYRIGHT: (C)2009,JPO&INPIT
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