| 摘要 |
PURPOSE:To detect the completion of etching securely by a method wherein a pattern made of material which transmits no light and has a high etching rate is provided under an object to be etched which transmits light and dis appearance of the pattern is recognized. CONSTITUTION:A W-Al pattern 4 for detecting the completion of etching is formed on a GaAs substrate 1. After a wiring 5 is formed, a layer insulating film 6 made of SiO2 is laminated. Then a mask 8 for etching which has apertures 7 on the predetermined positions of the film 6 is formed. Then contact holes 9 for interconnection between the layers are formed by dry etching. By carrying out the dry etching further, the pattern 4 is removed and the ectching is terminated after the disappearance of the pattern 4 is recognized. With this constitution, as the pattern 4 can be discriminated easily from the substrate 1 by the difference of color or the like, the completion of the etching can be detected easily by recognizing the disappearance of the pattern 4 regardless to the aperture area of the contact holes.
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