Improved Process for Clear Defect Mask Repair
Original Publication Date: 1987-Aug-01
Included in the Prior Art Database: 2005-Feb-01
This process covers pinhole defects in chrome masks used in semiconductor devices. Dye is mixed into photoresist which covers the defect so that it will have a high enough optical density (OD) so as to be as opaque as the chrome. It is possible to repair clear defects in optical masks in which a novolak/diazoquinone resist is patterned to cover the defects with resist film. The product of that step is then carbonized by a high temperature bake to form a permanent patch over the defects. Using that procedure, it is necessary to isolate the item being baked in an inert atmosphere and the elevated temperature required degrades the optical density of the unprotected Cr.