a method and apparatus for treating the surface of a substrate includes generating ozone in a generation chamber by using an optical source and transporting the ozone to a treatment chamber containing the substrate . the surface treatment utilizes an optical energy source and the generated ozone . the generation chamber and the treatment chamber are initially isolated from one another , which allows for the selective regulation of delivering ozone from the generation chamber to the treatment chamber . preferably , a single optical source both generates ozone in the generation chamber and serves to clean and / or planarize the surface in the treatment chamber .