Pre-diffusion cleaning using ozone and HF

The mainstay cleaning process in the semiconductor industry has been the SPM > HF > APM > HPM sequence for over 20 years. However, device fabrication requirements are imposing more stringent constraints on factors such as surface roughness and metallic contamination. Environmental concerns are demanding a reduction in chemical and water consumption. Manufacturers are requesting tool simplification and cost reduction. The use of ozone in aqueous HF solutions has been demonstrated to address organic, metallic and particle contamination while regenerating a fresh chemical oxide film on silicon wafers, thereby offering a potential substitute to conventional cleaning processes.