Abstract:
THE SEPARABLE LAYERS OF A PHOTOGRAPHIC STRIPPING FILM. CONSISTING OF A COMPOSITE OF A LAYER OF SENSITIVE UNEXPOSED EMULSION (E.G. SILVER HALIDE) CARRIED UPON A PERMANENT SUPPORT LAYER (E.G. CELLULOSE NITRATE) AND STRIPPED FROM THE TEMPORARY SUPPORT LAYER AND SMOOTHLY ADHERED TO AN OBJECT SURFACE WITH THE PERMANENT SUPPORT LAYER ADJACENT THE SURFACE. THE EMULSION LAYER SUCCESSIVELY RECEIVES IMAGE-WISE EXPOSURE TO LIGHT IN A FAST EXPOSURE PROCESS, PHOTOGRAPHIC DEVELOPMENT AND RELIEF DEVELOPMENT; THE LAST BY AN ETCH-BLEACH PROCESS. THE UNDERLYING SUPPORT LAYER IS DISSOLVED IMAGE-WISE WITH HIGH-FIDELITY THROUGH THE RELIEF STENCIL IN THE EMULSION LAYER. EXPOSED AREAS OF THE OBJECT SURFACE THEN RECEIVE AQUEOUS BASED PROCESS HANDLING (E.G. ETCHING OR PLATING) THROUGH THE AQUEOUS RESISTANT COMPOSITE MASTER STENCIL FORMED BY THE EMULSION AND SUPPORT LAYERS.
Abstract:
Master pattern silver emulsion images of microelectronic artwork are altered in situ so that they can be used as master patterns to provide photocopies of the reverse images. The silver is dissolved out and the remaining gelatin relief is dyed to a threshold level of opaqueness by an absorbed dye to produce the reversed master pattern image. Results of unusually fine detail resolution and contrast quality are achieved with substantial cost savings. Costs and risk of damage, due to excessive handling of the hard-to-replace masters in the alteration process, are reduced with undiminished quality of results by employing electrical means to control agitation of the silver dissolving agent. In a preferred exemplification, handling is further reduced by combining dissolution and dyeing phases of the process into one operation. Images on the reversed masters have better edge contrast quality than the original masters. This effect is used to advantage to improve masters which originally have poor edge definition.