MASK BLANKS - HIGHLY POLISHED, HIGHLY FLAT GLASS OR SYNTHETIC QUARTZ SUBSTRATE COATED WITH A THIN FILM OF CHROMIUM (OR SIMILAR OPAQUE MATERIAL) AND A PHOTO RESIST OR ELECTRON BEAM RESIST. THE RESIST IS SENSITISED BY U.V OR ELECTRON BEAM RADIATION IN PATTERNS RELATING TO INTEGRATED CIRCUIT DESIGNS, SENSITISED RESIST IS DEVELOPED AND THE REVEALED CHROMIUM IS ETCHED. AFTER THE REMAINING RESIST IS REMOVED A HIGH CONTRAST INTEGRATED CIRCUIT PATTERN OF CHROME AND TRANSPARENT SUBSTRATE REMAINS. THE RESULTANT PHOTO-MASK IS USED FOR THE PRODUCTION OF SEMICONDUCTOR DEVICES.

CLASSIFICATION IS DETERMINED BY GENERAL RULES 1 & 6 TOGETHER WITH THE TEXT TO CN CODES 3701, 370199 AND 37019900.