PURPOSE: To reduce a variation in a layer resistance value in a wafer plane due to the thickness of an oxide growth film and the diffusion of impurities in a horizontal diffusion furnace.
CONSTITUTION: In a horizontal diffusion furnace, a fork to get a semiconductor wafer in and out of the furnace is changed from a conventional flat plate-like one to a low heat capacity-type fork which has a plurality of cutoffs 1 on its outer part and in the center. By this modification of the shape, the fork itself has a small heat capacity. By this, when an empty fork of the room temperature is getting into a furnace core tube of high temperature at a constant speed to pick up a semiconductor wafer, the temperature of the fork itself suddenly ruses easily. Therefore, the cooling down of parts of the wafer which are brought into contact with the fork can be alleviated. As a result, a variation in a layer resistance value in a wafer plane due to the thickness of an oxide growth film and the diffusion of impurities can be reduced.
YAMAGUCHI YUJI
MOROTA SEIJI
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