Karl Suss MA-6 Vacuum Chuck Drawing

When doing backside alignment on the Karl Suss, you must look from underneath, through the transparent vacuum chuck, for the alignment marks on the backside of your wafer. Although the chuck is largely transparent, there are a lot of channels criss-crossing the chuck (for vacuum) which are not transparent. Thus, when designing masks which will be used on the Karl Suss for backside alignment, it is helpful to place your alignment marks so that they can be easily seen and found between the channels. The drawing below is of the 4" Karl Suss vacuum chuck, in millimeters (click on the drawing for a larger view.)