| 摘要 |
PURPOSE:To improve the mask superposing accuracy by oxidizing a resist hole by plasma oxygen ashing, and whitening the oxidized part of the hole to form a mask alignment pattern with an etchant having a slow etching rate. CONSTITUTION:A photoresist 2 is formed on a GaAs semiinsulating substrate 1, a resist hole 3 is formed at a desired part to form a resist pattern, and with the pattern as a mask the surface of the substrate 1 is oxidized by plasma oxygen ashing. The oxidized layer is whitened with an etchant having a slow etching rate to form a mask alignment pattern 5. Thus, the etched part becomes a whitened mask alignment pattern to eliminate a displacement from the resist pattern. |
