Showing papers on "Resist published in 1971"

Method of making semiconductor device

Abstract: A SEMICONDUCTOR DEVICE IS MADE BY FORMING ON THE SURFACE OF AN ELECTRICAL INSULATING SUBSTRATE A PLURALITY OF SPACED REGIONS OF A SEMICONDUCTOR MATERIAL. A MASKING LAYER IS PROVIDED ON THE SURFACE OF EACH SEMICONDUCTOR REGION. A LAYER OF AN ELECTRICAL INSULATING MATERIAL IS COATED ON THE SURFACE OF THE SUBSTRATE BETWEEN THE AROUND THE SEMICONDUCTOR REGIONS AND OVER THE MASKING LAYERS ON THE SEMICONDUCTOR REGIONS. A PHOTOSENSITIVE RESIST IS COATED OVER THE INSULATING LAYER. OPENINGS ARE PROVIDED IN THE RESIST OVER EACH OF THE SEMICONDUCTOR REGIONS USING THE MASKING LAYERS TO DEFINE THE OPENINGS. THE EXPOSED PORTIONS OF THE INSULATING LAYER OVER EACH OF THE SEMICONDUCTOR REGIONS AND REMOVED LEAVING THE INSULATING LAYER BETWEEN AND AROUND THE SEMICONDUCTOR REGIONS.

Thermally stable photoresist polymer

Abstract: A new photoresist stable to 500°C has been developed. The addition of potassium dichromate to a polyamic acid, believed to be the condensation product of pyromellitic dianhydride and 4,4′-diaminodiphenylether, results in a photosensitive polymer which can be cast or spun. The resultant film after exposure, development and post-bake is a crosslinked aromatic polyimide. An efficient developing solution consisting of a 5:1 mixture of hexamethylphosphoramide and dimethylsulfoxide has been discovered. The system has been fully characterized in terms of composition, film formation, exposure, development, hardening and removal. This material has already proven useful as an area-controlled, thermally stable dielectric and as a sputter-etch resist. It has been demonstrated that under the conditions of sputter-etching (bombardment of substrate with Ar, Ar+ species with energies from 1–300 eV) commercial photoresists, of the polyisoprene variety, char to the extent of being ineffective as a masking material. Under these same conditions, the thermally stable resist retains its film integrity and uniform sputter-etch rate. An exemplary processing sequence is included as an appendix.

Electrically conductive components

Abstract: Metal elements, usually of refractory metal, for electrical devices such as filaments for incandescent lamps, discharge lamp cathodes, grids or heaters for thermionic valves and radiation elements for electric heaters are made by forming an etch resist pattern on a metal web, etching the web, removing the resist and bending the etched product into compact form. The element produced has a substantially rectangular section which provides a high surface area to cross-sectional area ratio, leading to high thermal and light emission efficiency.

Modulation Transfer Function of AZ111 Photoresist.

Abstract: For the utilization of photoresist materials it is desirable to describe quantitatively the photoresist image and thereby introduce control over photoresist processing. The photoresist AZ111 has been shown to be a linear image recording medium and a modulation transfer function (MTF) defined and measured. Measured and calculated image profiles in this resist are quite comparable.

Two resist method for printed circuit structure

Abstract: AN IMPROVED METHOD IS PROVIDED FOR PLATING CONDUCTIVE MATERIAL IN A PREDETERMINED PATTERN ON A CONDUCTIVE LAYER THAT IS THEREAFTER ETCHED TO THE SAME PATTERN AS THE PLATED MATERIAL OR IS ETCHED TO THE PATTERN THAT EXTENDS BEYOND THE REGION OF PLATING. TWO LAYERS OF PHOTOSENSITIVE RESIST ARE APPLIED ONE OVER THE OTHER TO THE CONDUCTIVE LAYER. THE FIRST OR INNERMOST RESIST LAYER IS DEVELOPED TO MASK THE CONDUCTIVE LAYER IN THE AREAS THAT ARE LATER TO BE REMOVED BY ETCHING. THE SECOND RESIST LAYER IS DEVELOPED TO EXPOSE REGIONS OF THE CONDUCTIVE LAYER THAT ARE TO BE PLATED. AFTER THE PLATING HAS BEEN COMPLETED, THE SECOND RESIST IS REMOVED. THE STRUCTURE IS THEN PLATED WITH AN ETCH RESISTANT METAL IN AREAS NOT MASKED BY THE FIRST RESIST. THE FIRST RESIST IS REMOVED AND THE UNWANTED REGIONS OF THE CONDUCTIVE LAYER ARE ETCHED AWAY. THIS METHOD IS PARTICULARLY USEFUL FOR PLATING CONDUCTIVE STUDS IN A MULTI-LAYER PRINTED CIRCUIT STRUCTURE. THE SIDES OF THE STUDS ARE PROTECTED BY THE PLATED RESIST TO PREVENT THE STUDS FROM BEING ETCHED IN THE ETCH STEP.

Conductive designs and process for their manufacture

Abstract: PRINTED CIRCUITS, INTEGRATED CIRCUITS, RESISTORS, THERMOCOUPLES, CONDENSERS, SUPERCONDUCTORS, ELECTROFORMED MATERIALS, AND THE LIKE ARE PRODUCED BY PROVIDING A PLASTIC OR SUBSTANTIALLY NON-METALLIC SUBSTRATE WITH A METAL PHOSPHORUS COMPOUND; APPLYING A RESIST; REMOVING THE UNPROTECTED METAL PHOSPHORUS COMPOUND; DISSOLVING THE RESIST; AND SUBJECTING THE SUBSTRATE TO ELECTROLESS OR ELECTROLYTIC TREATMENT.

Chemical milling using fused powder particles as resist

Abstract: Method of chemical milling which comprises the steps of exposing a metal layer bearing a light-sensitive layer capable of developing a Rd of 1.0 to 2.2 to actinic radiation to produce a potential Rd of 1.0 to 2.2; developing said light-sensitive layer with water-insoluble powder particles using physical force to embed the powder particles in the light-sensitive layer; removing non-embedded powder particles; fusing the water-insoluble powder particles to the metal layer by heating to form a stencil; and etching through the metal layer in the areas unprotected by the fused water-insoluble powder particles.

Light-sensitive mixed esters of polyvinyl alcohol

Abstract: LIGHT-SENSITIVE FILM FORMING POLYMERS ARE DISCLOSED WHICH COMPRISE RECURRING UNITS OF BENZOATE- AND FUROATE-ESTERIFIED POLYVINYL ALCOHOL AS WELL AS THEIR UTILIZATION AS PHOTOGRAPHIC RESIST MATERIALS AND PRINTING PLATES FOR LITHOGRAPHY.

Method and article for color kinescope screen and mask production

Abstract: A METHOD FOR PRODUCING A COLOR DINESCOPE HAVING AN IMAGE SCREEN INCLUDING A PLURALITY OF PHOSPHOR AREAS AND A COLOR SELECTION BARRIER PREPARED FROM A PRELIIMINARY MASK USED FOR SCREEN PRINTING. THE PRELIMINARY MASK IS MADE BY DISPOSING AN APERTURED LAYER OF A SECOND METAL ON ONE SURFACE OF A SUBSTRATE OF A FIRST METAL, DISPOSING A PERFORATED RESIST FILM ON ANOTHER SUCH SURFACE, ETCHING PORTIONS OF THE SUBSTRATE THEREBETWEEN TO PROVIDE APERTURES LARGER THAN THOSE OF THE METAL LAYER, AND REMOVING THE RESIST FILM. THE PRELIMINARY MASK IS USED FOR PRINTING THE PHOSPHOR AREAS AND THE APERTURED METAL LAYER REMOVED TO PRODUCE A COLOR SELECTION BARRIER. THE PRELIMINARY MASK MAY BE USED TO PROVIDE A DARK MATRIX TO THE IMAGE SCREEN.

Method of producing thick schottky-barrier contacts

Abstract: Method of producing precise relatively thick metal-semiconductor contacts (Schottky-Barrier contacts) comprising, applying a layer of a photosensitive resist material onto a semiconductor surface having discrete metal areas thereon, subjecting the resist layer to controlled amounts of light so that the areas of the resist overlying metal areas are rendered soluble while other areas thereof remain insoluble, removing the soluble areas of the resist layer, applying a protective layer, as of metal, onto the exposed metal areas, and then removing the insoluble areas of the resist layer.

Producing printed circuits by using powder-embedded composition as etch-resist

Abstract: METHOD OF FORMING A PRINTED CIRCUIT WHICH COMPRISES THE STEPS OF EXPOSING AN INSULATING BOARD BEARING A CONDUCTIVE METAL SUBBING LAYER, SAID CONDUCTIVE METAL LAYER BEARING A LIGHT-SENSITIVE LAYER CAPABLE OF DEVELOPING A RD OF 1.0 TO 2.2 TO ACTINIC RADIATION TO PRODUCE A POTENTIAL RD OF 1.0 TO 2.2, DEVELOPING SAID LIGHT-SENSITIVE LAYER WITH WATER-INSOLUBLE POWDER PARTICLES USING PHYSICAL FORCE TO EMBED THE POWDER PARTICLES IN THE LIGHT-SENSITIVE LAYER, REMOVING NON-EMBEDDED POWDER PARTICLES FROM THE NONIMAGE AREAS, FUSING THE WATER-INSOLUBLE POWDER PARTICLES TO THE METAL SUBBING LAYER BY HEATING, AND ETCHING THE METAL LAYER IN THE AREAS UNPROTECTED BY THE FUSED WATERINSOLUBLE POWDER PARTICLES.

Improvements relating to the manufacture of thick film circuit elements

Abstract: 1,241,121. Resistance elements; printed circuits. FERRANTI Ltd. 27 Feb., 1970 [28 Feb., 1969], No. 10731/69. Headings H1R and H1S. A process of manufacturing a thick film circuit element comprises applying an adherent layer of photo-resist material 12 to a plane surface 11 of a laminar ceramic substrate, forming apertures 13 in the photo resist layer corresponding to the required element profile by known methods (e.g. photolithography), applying a paste 14 of the thick film material on to the substrate through the apertures and in the required sequence removing the photo resist mask, hardening the paste and bonding the element to the substrate. The element paste which may be applied manually 15 or screen printed on to the substrate includes a binder such as a glaze in its composition. The resist material may be removed by stripping or by a solvent. Where the element is bonded to the substrate by the glaze the resist material may be removed when the element is fired at a high temperature. The sheet of photo resist material (e.g. " Riston " (Registered Trade Mark)) has a minimum thickness of 0A001 inch. By increasing the thickness of the resist or using multiple layers circuit elements of different thicknesses can be made. An initially-liquid photo-resist material may be used to obtain the required thickness.

Printed circuit boards with through plated - holes

Abstract: The double sided, not etched, laminate is drilled and dipped in a liquid form of conductive Ag. The Cu cladding is then coated with plating resist and a thin Cu plating applied to the walls of the holes. After this the cladding is cleaned and a negative version of the conductor pattern is silk screen printed on both faces using a further plating resist. The conductor pattern so exposed and the walls of the holes are then reinforced with additional plating and then overplated with Au as an etch resist. The plating resist is cleaned from the areas to be etched away and this process then carried out leaving the positive conductor pattern on both faces.