| 摘要 |
PURPOSE:To improve position detecting sensitivity and to eliminate a problem such as an etching residue or the damage of a substrate by forming a recess formed on the substrate and having a sectional shape which extends toward the interior of the substrate in its thicknesswise direction from the surface of the substrate. CONSTITUTION:A substrate 1 employs an SI-GaAs substrate, and is covered as an etching resistant layer 2 an SiO2 layer or an Si3N4 layer. Then, the sub strate is entirely coated with a photoresist 3, a positioning mark forming region is opened by a normal lithography to form a resist pattern, with the pattern as a mask the layer 2 is opened by etching. The layer 2 is etched by a dry etching using carbon tetrafluoride CF4 as an etching gas or an ion beam etching. With the photoresist 3 and the layer 2 as masks it is wet etched to form a dug recess 4 on the substrate 1. GaAs is set etched with sulfuric acid, hydrogen peroxide, water or potassium hydroxide, hydrogen peroxide, or water etchant. The photoresist 3 and the layer 2 are removed.
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