| 摘要 |
PURPOSE:To form an excellent window for contact by performing anode oxidation by using electrolytic solution containing fluoric acid and thereby removing in a short time a nitride film provided on a semiconductor wafer completely. CONSTITUTION:The wafer having an epitaxial layer 2 wherein an element region is to be formed is prepared n a semiconductor substrate 1. After the element region is formed, openings are made selectively in a silicon oxide film 5 and a phosphorus glass layer 6 and thereby contact parts are formed. Consecutively, a silicon nitride film 7 to be a surface protecting film is made to grow on the whole surface of the wafer. Next, current is made to flow in the electrolytic solution containing fluoric acid and only the nitride film in the part of the window for contact is removed through melting by the method of anode oxidation. Since the fluoric acid is contained in the electrolytic solution, the nitride film subjected to the anode oxidation is melted quickly, and as the result, the nitride film can be removed completely in a short time. The appropriate density of the fluoric acid is 1:100-1:50 of fluoric acid to electrolytic solution in the content ratio. |
