PURPOSE: To ensure the high-accuracy formation of minute electrode window while keeping a matching between the semiconductor layer and the edge of the insulator layer by using SiO2, Si3N4 and the polyimide-group resin which feature the different etching solutions.

CONSTITUTION: Si3N43 is provided on SiO22 on P-type Si substrate 1. and film 3 is etched selectively via the heat phosphoric acid. Poly Si layer 4 is provided at the opening part through the photo etching method, and SiO22 is removed selectively via the HF-group solution. With the phosphorus diffusion given through the opening, N-layer 7 and 8 are obtained, and layer 4 features the conductive property to be covered with SiO29 and 10. After this, polyimide resin 11 is coated up to the same level as layer 4 with the heat treatment applied, and then the photo etching is given under the semi-hardened state to drill opening 12 and 13. The etching solution uses the aqueous solution of 40∼80 hydrazine and does not etch film 2 and 3, thus a high- accuracy not required for opening 12 and 13. Then a heat-treatment is given at about 300°C to secure hardening. Film 9 and 10 are then etched selectively via the HF-group solution to form Al wirings 14∼16. Thus, the matching is secured between wiring 14/15 and N-layer 7/8 with no short circuit caused to the adjacent regions.