Showing papers on "Resist published in 1972"

Computer-controlled resist exposure in the scanning electron microscope

Abstract: In modern microelectronics, complicated structures with very small dimensions must be fabricated on active-device materials. This task has been traditionally accomplished by photolithographic techniques, but electron-beam exposure of resist materials has recently been explored [1]-[3]. Submicron electron devices have been fabricated in several laboratories, often featuring a flying-spot scanner to generate the pattern being exposed [4]-[7]. Paper tape drives have been used for repetitive patterns [8], and computer control of the electron beam has been reported also [1], [9]. The electron resist that has shown the highest resolution to date appears to be poly-(methyl methacrylate) (PMM). We have used this material in a resist form for microelectronic device fabrication, and in bulk form to determine energy dissipation profiles. The exposure is performed with a computer-controlled scanning electron microscope (CCSEM). In this paper, we describe the electron beam system briefly, discuss the processes involved in resist exposure and development, describe our exposure procedures using the CCSEM, and show results of fabricated devices and energy dissipation studies.

Method for making photoresists

Abstract: A process for forming a photoresist which comprises: (1) applying to a surface the surface of a solid unexposed photosensitive layer of thermoplastic photosoluble or photodesensitizable material, the other surface being adhered to a film support, then in either order (2) exposing the layer, and (3) stripping the support, and then (4) washing away the exposed areas of the layer. The surface bearing the resist can be etched, plated, or treated in other ways.

Ion bombardment fabrication of optical waveguides using electron resist masks

Abstract: Fabrication of a circular strip waveguide by ion implantation of fused silica through a mask made by electron‐beam exposure of polymethylmethacrylate (PMMA) is described. This technique has an advantage in its simplicity and the small number of processing steps involved. Guidance of 0.6328‐μm light from a He–Ne laser through the guide is demonstrated.

Etching of polyimide films

Abstract: A process for the etching of polyimide films which includes applying a photo sensitive resist of a predetermined viscosity and utilizing hydrazine as an etchant to remove unwanted sections of the polyimide film after exposing and developing the light sensitive resist.

Electron beam sensitive polymer t-butyl methacrylate resist

Abstract: Patterns, such as etch resistant resists, masks, are formed by degradation of a t-butyl methacrylate polymer coating, or film, under an electron beam in a predetermined pattern, followed by removal with a solvent, of the electron degraded product in the exposed areas.

Electron beam patterning system for use in production of semiconductor devices

Abstract: This Specification describes the method and apparatus for the exposure of sensitive resists by the use of closely scanned rasters described by a focussed electron beam. Variation in the line width is used to produce different raster shapes as required. A succession of similar rasters can be described spaced over a semiconductor wafer for the purpose of producing the patterning required for the production of a plurality of similar semiconductor devices on the single wafer. A technique for aligning the wafer with the scan of the electron beam is described using markers distributed over the surface of the wafer there being one marker for each small raster to be described by the beam from the wafer; one alignment system using a cathode-ray tube display of the images of the reference marker magnified and placed closed together on the screen so that errors in alignment can readily be detected.

High sensitivity negative electron resist

Abstract: A technique is described for the generation of a relief image in a sensitive negative electron resist based upon a modified polymer of glycidyl methacrylate alone or in combination with methyl methacrylate and/or ethyl acrylate. The described resist evidences optimum characteristics with respect to sensitivity, adhesion and resolution and is suitable for use as an etch mask in the fabrication of microelectronic devices.

Dual resist usage in construction of apertured multilayer printed circuit articles

Abstract: Novel dual resist masking techniques are introduced for protecting surfaces of a multilayer pre-perforated foil clad object during etching and plating processes The primary mask attached directly to object surfaces is a thin high resolution film specifically adapted not to clog the perforations It is developed from a liquid-type photo-resist which forms an irregular and imperfect cover at edges of surface incisions such as perforation rims and etched channels The secondary mask adherent directly to the primary mask is formed from a thick layer of photopolymerizable solid film resist Development is controlled to preserve the integrity of form and adherence of the underlying primary mask The secondary mask serves principally to mask edges of surface incisions at perforation aperture rims and etched line channels It is applied in sufficient thicknesses to completely span the apertures and fully cover etched incisions without shearing or cracking at sharp projecting edges

Positive and negative photoresist applications of thin films surface‐photopolymerized from hexachlorobutadiene

Abstract: Polymeric films deposited from the vapor of C4Cl6 by the surface-photopolymerization technique are electrically and mechanically continuous on various substrates when very thin. The thickness of the films depends upon irradiation time with wavelengths in the region 2000-3000A. Re-irradiation in oxygen (air) of the polymeric films with light of these low wavelengths leads to patterned removal of the films. Since films 500A thick and less can resist etchants for various substrates, a new and extremely thin positive photoresist system is possible. Resolution of etched substrates to lines a few microns wide has been demonstrated. If the polymeric films from C4Cl6 are deposited from the monomeric vapor at lower substrate temperatures they are soluble in various solvents. Re-irradiation with UV light with the films in vacuum produces a patterned fixing of the polymer with respect to acetone. A negative photoresist system is therefore possible. Again, films of thickness 500A and less can resist various etchants such that substrates can be etched to high resolution.

Method for etch resist coating of plated holes in printed circuit boards

Abstract: Etch resist coating is applied into the plated holes in a printed circuit board by dipping the board in a liquid etch resist solution of fairly low viscosity, squeezing the etch resist into the holes by pressing the board between opposed press rolls, followed by first squeegeeing the top and then the bottom of the board to wipe both surfaces. This results in a resistcoated hole.

A microcircuit and manufacture of same

Abstract: 1287791 Circuit assemblies HONEYWELL INFORMATION SYSTEMS ITALIA SpA 31 Oct 1969 53604/69 Heading H1R A microcircuit comprises an insulating substrate 1 supporting conductors such as 2 each comprising a first thin layer 2a, a second thin layer 2b and an electrolytically deposited layer 2c, the conductors being separated from further conductors such as 4 crossing them by insulating layers 5 To construct the circuit, the substrate is covered with a vacuum deposited layer of nickel-chromium alloy, then a vacuum deposited gold layer followed by a layer of photo-sensitive resist material A conductor pattern is defined on the resist layer using a mask and is exposed by solution of the resist layer covering it After the electrolytic deposition of gold to form the third layer, the remaining photo-resist layer is removed and the underlying thin metal layers etched away Alternatively it is the resist layer covering the unwanted part of the conductor layer which is first removed, followed by the unwanted conductive layer Electrodeposition of gold follows removal of resist from the pattern Then the insulating layer 5 is applied by silk-screening ceramic material and, as shown, the cross-over conductor 4 is formed in the same way as conductor 2 Alternatively it may be screen printed

Paper-tape-controlled electron probe resist exposure and direct metallic deposition

Abstract: Computer-aided design techniques are now used extensively for the production of masks in the microelectronic industries. In these methods the microcircuit patterns are broken down into simpler component parts, such as rectangles, whose co-ordinates are punched onto paper tape. A logic system has been developed to control an electron probe from coordinates read in on paper tape. Successive rectangles specified on the tape are scanned by the probe on the specimen, exposing an electron-sensitive material. A microcircuit pattern is thus built up from these basic rectangular elements. The use of an electron probe allows the generation of patterns with submicron dimensions within a reasonable time. The system outlined above has been used to produce microcircuit patterns using two techniques. In one, electron-sensitive resist is used to define a pattern etched in underlying material; in the other, metallic patterns are deposited directly by the decomposition of a metallic compound.

Charge storage target and method of manufacture

Abstract: A charge storage device of the type in which a target electrode provides a plurality of spatially distributed charge storage sites formed on an output side of semiconductor wafer with means associated with the storage sites for sensing and converting the charge on the storage sites into an electrical signal. Input excitation is directed onto the other or input side of the semiconductor wafer and may be in the form of electrons or light capable of generating electron-hole pairs within the semiconductor wafer which diffuse through to the storage sites. The output side of the semiconductor wafer is provided with an apertures insulating layer with a reading electron beam making contact through the apertures in the insulating coating to the spatially distributed storage sites within these apertures. This invention is directed to an improvement in the structure and the process for manufacture thereof wherein pillars of the semiconductive wafer extend from the substrate of the wafer above the insulating layer and a semiconductive region of opposite type conductivity to that of the wafer is provided in the top of the pillar and an electrical conductive contact is provided on the top of said pillar for better electron beam contact to the target. The invention is directed to this structure and the process of fabricating the electrical contact onto the top of the pillar. The process includes the spinning of a resist coating over the pillared surface of the target in such a manner to provide a desired resist pattern for the manufacturing process and thereby avoids other difficult masking process steps.

Model of negative working photoresists as continuous tone photographic materials.

Abstract: A four-parameter model is presented that describes the relief height response of negative working photo-resists. It is shown that the resist thickness after development is directly proportional to the logarithm of the exposure over a wide range of exposures. A relationship between this thickness and exposure is derived and shown to predict resist response. Resists can usefully record exposures that vary by a factor of 10 million making them ideal materials for recording wide dynamic ranges. Several applications using these unique properties are presented.

Mechanism of the Action of an Electron Beam on Organic Photoresists

Abstract: The literature dealing with the decomposition of positive and negative photoresists by actinic light and by electron bombardment is reviewed, and the action of a stream of electrons on other organic materials, metals, and inorganic dielectrics is discussed. A mechanism producing internal irradiation of the resist is considered: the incident electrons excite the resist molecules into fluorescence and phosphorescence. The influence of the (metallic or dielectric) substrate on the achievement of the required line widths is discussed. It is shown that the cross-linking of a negative photoresist under the influence of an electron beam occurs by free-radical polymerisation. 65 references.

Production Engineering Measure for an Electron-Beam Machine and Microwave Transistors.

Abstract: : Significant steps were made toward establishing a fully computer-controlled electron-beam delineation capability for fabrication of microwave transistors. The first lot of slices (EBT-1) was processed through all the microwave transistor 'masking' levels to establish electron resist and etching processes. Significant problems were not encountered using PMMA RESIST UNTIL THE CONTACT 'MASKING' LEVEL. A CHANGE IN THE ETCH RATE OF THE SPUTTERED GOLD DUE TO ELECTRON-BEAM IRRADIATION CAUSED SEVERE UNDERCUTTING OF THE EMITTER FINGERS USING PMMA and conventional chemical etching techniques. A negative electron resist polystyrene was utilized on Lot EBT-5 to take advantage of this etch rate differential. Polystyrene enabled delineation of 0.7 m emitter contact fingers on all slices in this lot. Evaluation of the transistors from Lot EBT-5 is in progress. Excellent progress was made this quarter toward fully automating pattern registration for fabrication of 6 GHz transistors. Lots EBT-4 and EBT-5 were used to test the alignment capability of the automatic pattern registration (APR) system on wafers going through the 6 GHz transistor process. Another major step toward fully computer- controlled e-beam delineation was accomplished through assembly and check-out of the electrical and mechanical hardware necessary for the step-and-repeat operation. (Author, modified-PL)