| 摘要 |
PROBLEM TO BE SOLVED: To enable a megasonic cleaning device to be enhanced in cleaning efficiency without increasing a power density outputted from a transducer, by a method wherein a wafer is, at least, partially dipped into a degassed fluid, and sonic energy is transmitted to the wafer through the intermediary of the degassed fluid. SOLUTION: A degassing device 37 can be connected at an optional point along a chemicals circulating pipe 21. In operation, chemicals are fed from a tank 13 by a pump 27, degassed by a degassing device 37, and returned to the tank 13 at a flow rate of 5 to 10 l/min. Therefore, gas bubbles are hardly contained in chemicals kept in the tank 13. When a current is applied to a transducer T, it outputs acoustic waves 31 which travel to the surface of a wafer without being impeded by gas bubbles contained in a chemical solution. As a result, an efficient cleaning operation can be obtained without enhancing a power density outputted from the transducer T.
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