| 摘要 |
PROBLEM TO BE SOLVED: To improve a product yield by preventing formation of black silicon. SOLUTION: Predetermined amounts of gases of HBr, SF6 , SiF4 and HeO2 are introduced into an etching chamber, a single sheet of substrates is etched and removed from the chamber, and a cleaning-exclusive dummy substrate having an SiO2 layer formed on an Si substrate is placed in place of the etched substrate to carry out a single-wafer cleaning step CL1. The step CL1 includes a cleaning step C1 for 80 seconds, a seasoning step S1 for 20 seconds, and a purge step P1 for 60 seconds. In the step C1, a reaction product adhered onto walls of the etching chamber is removed by etching using the SF6 gas. In the step S1, the atmosphere and substrate temperature are adjusted to remove the reaction product by etching in the step C1. In the step P1, the gases are made to flow in such a condition as not to generate a gas plasma, thereby removing foreign matter remaining as floating in the etching chamber after the step S1. As a result, a predetermined trench shape can be obtained without forming black silicon, and a product yield can be improved.
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