If you will be using dry etchers such as the lampoly and p5000 etchers you may be required to mask the outer 5mm of your wafers to remove the photoresist. This prevents problems with the etchers such as the clamp fingers sticking to photoresist on the top edge of the wafer. The procedure follows, but contact Margaret Prisbe or Mahnaz Mansourpour for the mask, and for any questions about the procedure that you may have.

• The mask is a 5 inch contact mask. It can be used on either the karlsuss or the evalign.
• After your wafers have been coated and baked use the karlsuss or evalign to pattern the outer edge of your wafers.
  • Expose using EDGE EXPOSURE REMOVAL MASK (see Margaret or Mahnaz)
  • Use soft contact
  • When you load your wafer, center it so that you get a 5mm removal of resist on the outside. Expose one wafer, develop it and inspect it before doing the rest of your wafers.
  • Over expose (to make sure all the resist is removed from the area during develop)
• Then do your normal exposure on whichever alignment tool you normally use (you will do both exposures, and develop only one time).
• Develop your wafers and inspect.
  • You should find that the outer 5mm of resist has been removed and that your pattern on the rest of the wafer is fine.