PURPOSE:To clean a plurality of wafers efficiently by a method wherein the perforated holes in which wafers are immersed and held with their semiconductor elements forming surfaces upside are provided at the center of a plurality of bases and these bases are piled by supporting culumns with a certain interval and supersonic vibration is applied from the top onto the element forming surfaces. CONSTITUTION:A wafer holder 30 is composed of a plurality of bases 20 each of which holds a wafer and which are piled by supporting culumns 25 with a certain interval. A through-hole 22 which has a diameter a little bit larger than that of the wafer 21 and in which the wafer 21 is stored with its element forming surface upside is perforated in each base 20 and the wafer 21 is immersed in the hole 22 with its top surface at the same level as the base and prevented from dropping by a circular supporting edge 23 provided in the hole 22. The circumference of the wafer 21 is fixed by the fitting 24. With this constitution, the wafer 21 is immersed in each base 20 and supersonic vibration is applied from the top of the holder 30 to make foreign substances on each element forming surface drop off.
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