Solution for etching a thin film transistor and method of manufacturing the same

A method of manufacturing an aqueous alkaline etching solution comprising:

• mixing an alkaline material;
• and water;
• the alkaline material being selected from the group consisting of ammonium hydroxide, a quaternary ammonium hydroxide, an alkali metal hydroxide, an alkaline earth metal hydroxide, an ammonium phosphate, a quaternary ammonium phosphate, an ammonium carbonate, a quaternary ammonium carbonate or a combination comprising at least one of the foregoing alkaline materials;
• the aqueous alkaline solution being operative to etch aluminum oxide at a rate greater than or equal to about 2:1 over a rate at which it etches a metal oxide semiconductor to be protected;
• wherein the aqueous etching solution has a pH of 8 to 13.

A method of using an aqueous alkaline etching solution comprising:

• disposing a metal oxide semiconductor device into the aqueous alkaline etching solution;
• where the metal oxide semiconductor device comprises a dielectric layer that comprises an aluminum oxide layer disposed upon a metal oxide semiconductor layer;
• and
• wherein the aqueous alkaline etching solution comprises an alkaline material and water;
• the alkaline material being selected from the group consisting of ammonium hydroxide, ammonium phosphate, quaternary ammonium hydroxide, quaternary ammonium phosphate, ammonium carbonate, quaternary ammonium carbonate, an alkali metal hydroxide, an alkaline earth metal hydroxide, or a combination comprising at least one of the foregoing alkaline materials;
• the aqueous alkaline solution being operative to etch aluminum oxide at a rate greater than or equal to about 2:1 over a rate at which it etches the metal oxide semiconductor layer;
• wherein the aqueous etching solution has a pH of 8 to 13.