The Study of Mask Crosstalk Defects from Developer and Etching

Photomasks constitute a critical part of the electronic circuit device manufacturing processes. A photomask morphs into design patterns of devices through a lithographic process. Any defects on a photomask will cause repeating defects in circuits lead to yield loss. However, most of defects generated in mask fabrication processes have been mainly created during each unit process. A different formation mechanism defect which formed between processes to processes was studied in detail and different from previous defects. In this paper, we introduced two different defects formed at mask making stage. The phenomenon was believed the Crosstalk defect between develop to etch process is considered to after develop residue chemical reaction to dry etching plasma component generation ammonium salts as defect source. To recover the defects, the first one used the longer and strong rinse to remove the salt as far as possible and the second one used the optimized etch recipe by change bias power to minimum the formation of salts. The long-term monitor data showed the defects counts could be reduced from hundreds defects to less than 15 counts.