March 2007 -- Baumer Electric has designed and developed long range wafer mapping sensors. Wafers are carried between different stages of manufacturing in FOUPs (cassettes). To prevent wafer damages during handling processes, wafer grippers need to know the precise vertical positions of the wafers, and whether they are cross or double slotted. Sensors are used in this application to detect the stacked wafers from the open side of a FOUP.
The patented laser diffuse sensor with background suppression has a laser line as an emitting beam, high accuracy optics and signal compensation to allow a high excess gain on standard 300 mm wafers. Because of this technology, it is possible to detect wafers reliably and with a very high repeatability, independent of their surface quality or coating. The sensor detects the wafers even if a notch or a flat is in front of the sensor. The far distance sensing permits a mounting of the sensor sideways, ie, 45° to the access axis of the FOUP. This keeps the area in front of the FOUP free from the grippers. Due to the background suppression feature, the back of the FOUP does not interfere with the wafer detection, whether it is white, black or orange.
The sensor only needs to be aligned to the wafer at installation, no adjustment necessary. The sensor can also be used for detecting CDs and shiny or highly reflective metal disks.
For more information contact Andy Brown, Temperature Controls, +27 (0)11 791 6000, andyb@tempcon.co.za
Credit(s)
Supplied ByTemperature Controls
Tel(011) 791 6000
Fax(011) 792 1140
sales@tempcon.co.za
www.tempcon.co.za
