Patent ID: 7638004

Claim:
A method of cleaning a sapphire microwave plasma applicator tube, the method comprising: preparing a sapphire microwave plasma applicator tube for cleaning; performing a first set of cleanings of the sapphire plasma applicator tube, the first set of cleanings including, a first wash to remove organic contaminants from the tube, a second wash with water to remove water soluble contaminants, and a third wash using an ammonia and peroxide containing solution to remove contaminants from the tube; performing a second set of cleanings of the plasma applicator tube, these including, a fourth wash with an alkaline cleaning solution to remove AlF x contaminants from the tube, the fourth wash being performed for at least 60 minutes at a temperature of about 80° C. or greater, the x being any integer, wherein the alkaline cleaning solution contains tetramethyl ammonium hydroxide (TMAH); and a fifth wash with an acidic cleaning solution to remove selected metal contaminants from the tube, the fifth wash being performed after the fourth wash, the acidic cleaning solution including hydrofluoric acid, nitric acid and water, the wash being performed for at least 10 minutes at a temperature of about 80° C. or greater.