| 摘要 |
<p>1,210,949. 949. Photo-masks. INTERNATIONAL BUSINESS MACHINES CORP. May 31, 1968 [July 3, 1967], No.26081/68. Headings G2C and G2M. Photo-masks are prepared by forming a developed image in a gelatine coating on a transparent substrate, heating to at least 250‹ C., and selectively removing the gelatine from the non- image areas. Preferably a gelatine silver halide emulsion is imagewize, developed and fixed and the gelatine removed from the non-image area by an aqueous alkaline solution of an oxidising agent (e.g. a hypohalite, KMnO 4 or H 2 O 2 ), or HCL vapour. The photo-masks may be converted into reverse masks by coating with a metal layer (e.g. vacuum deposited Cr, Sn, Al, Ni or Au), and removing the metal overlying the gelatine containing the developed image (e.g. with NaOCL), and then removing the gelatine (e.g. with dilute HNO 3 ).</p> |
