CPC H01L 21/02057 (2013.01) [B08B 3/12 (2013.01); B08B 13/00 (2013.01); G08B 21/182 (2013.01); H01L 21/67051 (2013.01)] | 16 Claims |
1. A method for cleaning a semiconductor wafer comprising features of patterned structures, the method comprising:
applying liquid on the semiconductor wafer;
controlling, based on a timer, a power supply of a transducer to deliver acoustic energy to the liquid at a first frequency and a first power level for a predetermined first time period; and
controlling, based on the timer, the power supply of the transducer to deliver no acoustic energy to the liquid for a predetermined second time period, wherein the first and second time periods are alternately applied one after another for a predetermined number of cycles;
detecting a power on time of the power supply; and
shutting down the power supply when the power on time exceeds a first preset value.
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