| 摘要 |
PROBLEM TO BE SOLVED: To manufacture the phase shifted diffraction grating having excellent reproducibility, mass productivity and monomode selectivity by processing a silicon oxide film using periodic photoresist patterns as masks. SOLUTION: An silicon oxide film 2 is formed on an n type InP substrate 1 to be coated with high resolving power photoresist for i line. Next, photoresist patterns 3 are printed using Ar ion laser 4 for interference exposure in 240 nm and then the silicon oxide film 2 is processed to form silicon oxide patterns 5. At this time, the almost perpendicular shape is given to the silicon oxide patterns in the dimentional ratio of about 1.3 in thickness (h)/width (w). Later, a resist pattern 6 is formed on a part of the surface. Successively, an n type InP crystal is processed by dryetching and after the formation of a diffraction grating, the silicon oxide patterns 5 are etched away. |
