Glass Wafer Processing And Inspection For Qualification Of Reticles In A Fineline Wafer Stepper Production Facility

The concept of VLSI chip fabrication in a step and repeat lithography based facility varies significantly from that of the conventional 1:1 aligner based process. Whereas a 1:1 mask contains over 100 possible chip sites covering a five inch wafer, a 5:1 stepper reticle may contain as few as one chip site per exposure with two to four being more typical. This small reticle array is the stepped across the wafer to fill all possible chip postitions on the wafer. If a printable defect exists on the reticle then the final dis yield will directly experience a loss of anywhere from 25% (four chips per reticle) to 100% (one chip per reticle) of the potential chips in all lots exposed with that reticle.