| 摘要 |
An improved method and apparatus for cleaning semi-conductor wafers (30) in a liquid bath including means (14) for supplying the bath with a liquid media such as ultrapure water and with an electroacoustic transducer (18) disposed to energize the wafer (30) in the bath. The transducer (18) is energized at a frequency in the range of from about 20 kHz to 90 kHz to form a compact, well-defined area of intense cavitation in the bath. The workpiece is moved in a first direction past the transducer through the area of intense cavitation. The ultrapure water is moved past the transducer and the workpiece in a direction opposite to the direction of movement of the workpiece past the transducer. The improvement comprises the placement of the transducer (18) just above, out of contact with the surface of the bath, thereby minimizing the generation of flow turbulence in the bath which can redeposit dirt on the already cleaned surface of the wafer (30), and yet still satisfactorily imparting energy to the wafer surface when the transduceris actuated, forming a meniscus between the end of the transducer (18) and the liquid. |
