| 摘要 |
PURPOSE:To cause a small quantity of volatile elements present in silicon wafers to scatter so as to prevent contamination thereof, by subjecting the wafers cut from a single-crystal silicon ingot to a vacuum heat treatment process after they are washed and before they are received in a container. CONSTITUTION:A plurality of silicon wafers 1 cut from an ingot are washed in the washing process and sent to a vacuum heating treatment apparatus 4 by means of a conveyor 3. The treatment apparatus 4 is provided with a chamber 4a having inlet and outlet gates 4c and 4d and a vacuum pump 4e. In the apparatus 4, the wafers 1 are carried on a heater 4b incorporated therein and heated to 200-600 deg.C so that they are vacuum heat-treated under a vacuum of 1 Torr. A small quantity of volatile elements or molecules present near the surface of or within the wafer 1 are thereby caused to scatter. Then, the wafers are received in a clean plastic container 5a by means of a conveyor 3. In this manner, the wafers can be prevented from suffering from breakage of patterns or the like in the semiconductor device process.
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