Oc Oerlikon Balzers Ag

Ruedi Schmucki

Bart Scholte Van Mast

Holger Christ

The invention relates to a method for positioning a wafer () with a reference mark () in a vacuum processing unit with a transport chamber containing a transport device () for moving the wafers () in a plane to a process chamber arranged on said chamber and a single sensor (), arranged within the transport chamber before the process chamber for recording the position of the wafer () by means of recording the edge thereof at a first detection point () and a second detection point (), such that the actual position of the wafer () with a known wafer diameter can be determined with electronic analysis of both measured detection points () and the transport device () guides the wafer () to a desired set position. The wafer () is aligned in a given position on the transport device () in relation to the reference marks () thereof and the projection of the reference marks () determines a non-permitted zone () along a direction of movement on the wafer () and hence defines a free zone on the remainder of the wafer (). The sensor () is arranged in the transport chamber such as to guarantee that the non-permitted zone () is not scanned and the sensor () can thus only record the circular art of the wafer edge and not parts of the reference mark ().

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Buchs, Switzerland

Ruedi Schmucki