Process for manufacturing semiconductor wafers containing a gas-phase epitaxial layer in a deposition chamber
Disclosed is a process for manufacturing semiconductor wafers containing a gas-phase epitaxial layer in a deposition chamber, involving removing, from the deposition chamber by etching the deposition chamber, material settled in the deposition chamber during preceding coating processes; performing successive coating operations in the etched deposition chamber, each of said coating operations involving having a robot place a substrate wafer on a susceptor having a circular circumference, the robot moving the substrate wafer into a drop-off position and placing it on the susceptor, the center of the substrate wafer not lying over the center of the susceptor in the drop-off position because of a predefined corrective parameter; and depositing an epitaxial layer on the substrate wafer such that a semiconductor wafer containing an epitaxial layer is produced, characterized in that for each first substrate wafer moved by the robot into the drop-off position, the value of the predefined corrective parameter corresponds to a mean value of differences in the positions of a number of previously coated substrate wafers which had been the first substrate wavers to be coated following a preceding chamber etching operation.
1 . A process for producing semiconductor wafers with an epitaxial layer deposited from a gas phase in a deposition chamber, the process comprising:
removing, from the deposition chamber, material which has deposited in the deposition chamber in a course of preceding coating operations, by etching of the deposition chamber;
coating operations carried out in succession in the etched deposition chamber, in each case comprising:
placing a substrate wafer on a susceptor with circular perimeter by a robot, where the robot moves the substrate wafer into a placement position and places it on the susceptor, with a corrective precept causing a center of the substrate wafer not to lie above a center of the susceptor in the placement position; and
depositing the respective epitaxial layer on the substrate wafer to form a semiconductor wafer with the epitaxial layer, wherein:
for each first substrate wafer moved into the placement position by the robot after the etching of the deposition chamber, an amount of the corrective precept corresponds to an average of positional deviations of a number of previously coated substrate wafers themselves each the first to be coated after a preceding chamber etch.
2 . The process as claimed in claim 1 , wherein the number of the previously coated substrate wafers is at least three.