| 摘要 |
PURPOSE:To enable to form the sidewalls of the etching groove of a fine pattern so as to become smooth sidewalls by a method wherein step differences, which generated on the sidewalls of the etching groove created by performing a dry etching, are removed by performing a wet etching using a proper etching liquid. CONSTITUTION:An etching groove 7 is formed by a dry etching process. At this time, step difference parts generate on the sidewalls of the etching groove 7, but at this stage, a photo resist film 5 is used as a mask without being removed, and a wet etching is performed until the step differences between each of a first and a second clad layers 2 and 4 and an active layer 3, which is a second semiconductor layer, are eliminated using an etching liquid, hydrofluoric acid, for example, which is capable of selectively etching only a Ga1-XAlXAs layer, which is slow in etching speed in a dry etching process and is a layer left protrudedly, and after an etching groove 7a having smooth sidewalls was obtained, the resist 5 is removed. As a result, the etching groove 7a, whose sidewalls are fine and vertical, is easily obtained.
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