SC1 Cleaning Thermal Oxide Film Process Optimization Based on Box-Behnken Response Surface Method

With the continuous progress of integrated circuit manufacturing process, in order to ensure the yield of products, the surface quality of wafers after wet cleaning is required to be higher and higher. To control the thermal oxide film loss and the increase of within wafer non-uniformity caused by SC1 cleaning, the Box-Behnken Design method was adopted to design experiments and optimize the three key parameters of the SC1 cleaning process, namely the chemical temperature, chemical ratio ( V_\mathrmNH_4\mathrmO\mathrmH:V_\mathrmH_2\mathrmO_2:V_\mathrmH_2\mathrmO ) and process time, through response surface methodology. The influence of each factor and the interaction between factors on the cleaning effect was also discussed. The results show that when the cleaning time is fixed at 90 s and the cleaned thermal oxide film is 30 Å, the SC1 chemical with a temperature of 30 ℃ and a ratio of 1∶9.0∶50 has the least impact on the oxide film surface; when the chemical temperature is 60 ℃ and the ratio is 1∶3.0∶50, the maximum thermal oxide film loss thickness of 0.065 nm can be obtained while controlling the within wafer non-uniformity increment within 1%.; when the chemical temperature is 60 ℃ and the ratio is 1∶6.5∶50, the maximum thermal oxide film loss thickness of 0.043 nm can be obtained while controlling the within wafer non-uniformity increment within 0.5%; when the chemical temperature is 55 ℃ and the ratio is 1∶8.0∶50, the thermal oxide film loss thickness can be maintained at 0.020 nm while controlling the surface non-uniformity increment within 0.24%. This study has some reference value for the parameter selection of SC1 cleaning process in IC manufacturing.