As defects are getting to be one of the most critical issues for next generation mask fabrication, Photomask Japan '96 Symposium held a Round Table Discussion on mask defect issues including inspection and repair targeting 0. 1 8 im device design rule and below. To clarify issues on defect specification, fabrication process feasibility with Cr wet etching Idry etching, and equipments of defect inspection and repair, eight panelists made short presentations and discussed those issues with audience. From a device manufacturer's stand point, mask making is required one or two generations ahead from the present targeting design rules, which enables chip size smaller resulting in profitable memory devices. New type defects are listed from a mask shop as transmission defects, resolution limit defects, semi-transparent defects and corner rounding, for which the Cr dry etching is advantageous over Cr the wet etching. Equipment makers also summarized critical issues for next generation. Defect inspection systems have several tasks such as improvement in sensitivity tunable with defect printability, feasibility to new type defects above, shorter wavelength optics, new system performance benchmark procedure, and preprocess software improvement to cope with optical proximity effect correction and phase shifting masks. Defect repair systems have several tasks such as accuracy improvement, substrate damage reduction, non-Cr material repair, three dimensional repair for alternating phase shifting masks and capability of phase and transmission control. The Round Table was held on April 21, 1996 at Kanagawa Science Park, Kawasaki, Japan.
Keywords; mask, photomask, defect, defect inspection, wet etching, dry etching, defect repair, focused ion beam, optical proximity correction, mask data.