RECYCLING OF LARGE-SIZE PHOTOMASK SUBSTRATE Russian patent published in 2012 - IPC G03F1/42 

FIELD: physics.

SUBSTANCE: method comprises the following steps for (i) removing the pattern light-shielding film from the used large-size substrate of the photomask to provide a large-size photomask-forming glass substrate stock, which must be regenerated, (ii) resurfacing the glass substrate stock by sand blasting, (iii) repolishing the resurfaced glass substrate stock to obtain a regenerated glass substrate stock, (iv) applying a light-shielding film onto the regenerated glass substrate stock to obtain a regenerated large-size photomask-forming blank, and (v) processing the light-shielding film of the blank into a pattern corresponding to desired exposure of the mother glass, thereby obtaining a regenerated photomask substrate.

EFFECT: improved accuracy of exposure, especially accuracy and resolution of alignment.

6 cl, 4 dwg