Method of cleaning semiconductor wafers
A method of cleaning semiconductor wafers using an acid cleaner followed by an alkaline cleaner to clean contaminants from the materials is provided. The acid cleaner removes substantially all of the metal contaminants while the alkaline cleaner removes substantially all of the non-metal contaminants, such as organics and particulate material.
1. A method comprising, in sequence, the following:
a) applying an aqueous acid composition comprising one or more acids chosen from polycarboxylic acids and inorganic acids to a semiconductor wafer; and
b) applying an aqueous alkaline composition consisting of one or more alkaline compounds selected from the group consisting of sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium bicarbonate and tetra-methyl ammonium hydroxide, one or more polyglycosides or one or more glycosides or mixtures thereof, water and optionally, one or more additional surfactants to the semiconductor wafer to remove metals and residue from the semiconductor wafer.
2. The method of claim 1 , further comprising a step of applying a second acid composition comprising one or more acids chosen from polycarboxylic acids and inorganic acids to the semiconductor wafer subsequent to step b.
3. The method of claim 1 , wherein the aqueous acid composition further comprises one or more surfactants.
4. The method of claim 3 , wherein the one or more surfactants are nonionic.
5. The method of claim 4 , wherein the nonionic surfactant is chosen from a polyol and a gemini surfactant.
6. The method of claim 5 , wherein the polyol is chosen from a glycoside and a polyglycoside.
7. The method of claim 1 , wherein the polycarboxylic acid is chosen from a dicarboxylic acid, a tricarboxylic acid and an oxycarboxylic acid.
8. The method of claim 1 , wherein the semiconductor wafer is a monocrystalline or polycrystalline silicon.