| 摘要 |
PROBLEM TO BE SOLVED: To enable eliminating organic contamination and metal contamination of Cu, Fe, etc., of a silicon wafer with a short time treatment for several minutes, by holding a semiconductor substrate in an atmosphere containing mist sulfuric acid at a high temperature, and keeping the surface of the substrate in the state wetted with sulfuric acid. SOLUTION: Sulfuric acid 2 is accommodated at the bottom of a cleaning vessel 1 composed of quartz glass, a lid 3 composed of quartz glass is capped, and heating is performed with a heater 4. The liquid temperature of the sulfuric acid 2 and the temperature of an atmosphere 1a can be measured with a thermocouple arranged in a quartz glass tube. When the liquid temperature reaches 250 deg.C, a wafer 7 accommodated in a carrier 6 composed of quartz glass is put in the vessel and held above the liquid. In this step, the inside of the vessel is filled with white smoke of mist sulfuric acid. When slight exhaust is performed through a sulfuric acid gathering tube 9 which is filled with quartz wool 8, a small amount of air invades from a gap between the cleaning vessel 1 and the lid 3, and white smoke becomes more dense.
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