Advanced Cleaning Process for 1x Mask (Pmma Resist) to Remove Chrome Opaque Defects and Contamination
Original Publication Date: 1989-May-01
Included in the Prior Art Database: 2005-Jan-27
The continued presence of high chrome opaque defects (less than lum size) and contamination on mask product following the use of conventional cleaning methods results in excessive rejects. The rework process loop described in this article effectively cleans a large percentage of these rejects, thereby significantly improving mask product line yields. (Image Omitted) The process flow chart shown in the figure illustrates both a conventional mask cleaning procedure (solid line) and the disclosed rework process loop (dashed line). Masks normally proceed through conventional cleaning processes  and microscopic inspection (dimensional)  before reaching final product inspection (defects) , after they are either shipped out , transferred for specified repairs , or rejected  to automatic process restart.