Abstract: The invention relates to a process and apparatus for producing hollow glass microspheres. According to embodiments of the invention, particles of a soda-lime-silica glass containing slight amounts of sulfur compounds are suspended in a gaseous current and expanded in a burner, at a treatment temperature at least 100.degree. C. above the working temperature at which the specific type of glass constituting the treated particles is made from its raw materials, such as sand, lime, sodium carbonate, sodium sulfate, and others, depending on the particular type of glass. The process makes it possible to increase the yield of the transformation of the particles.

Abstract: A technique of forming fibers, employing a drawing apparatus which apparatus is comprised of a centrifuge combined with a hot gas flow produced by a burner. The burner emits a continuous envelope along the centrifuge. This envelope is produced such that it flow out at the origin of a hyperboloidal configuration. This outflow is produced by feeding the burner from feed conduits which are inclined with respect to the axis of the burner.

Abstract: A method for forming multiple metallization layers on a semiconductor wafer comprises applying insulating polyimide layers between adjacent metallization layers. Vertical interconnect holes are formed through the polyimide insulating layers using a positive photoresist mask. The vertical interconnect holes are etched using a fluorocarbon- or fluorosilicon-oxygen plasma under power and temperature conditions which provide for selectively etching the polyimide relative to the photoresist. By initially forming the plasma etch at high power conditions which reduce the selectivity for the polyimide, the upper portion of the vertical interconnect hole walls may be flared to reduce problems with step metallization. The remaining portion of the plasma etch, however, is performed under conditions which are more highly selective for the polyimide which provides for better dimensional control and eliminates formation of a contaminating layer at the bottom of the vertical interconnect hole.

Abstract: The method uses a raw-material and dopant-deposition technique, which requires vapor-state reactants and thermal sources for producing a temperature gradient suited to obtain a circularly and radially varying refractive-index profile in the supporting tube.

Abstract: The method allows surface defect reduction in silica optical-fibers by enriching the external layer by silica bonded carbon atoms within the silica lattice: SiC.SiO.sub.2. Carbon is obtained from chemical reaction directly during the drawing step. Volume defects are reduced by rapidly cooling the fiber structure heated up to vitreous transition temperature.

Abstract: The bushing balance controller is an electronic device which measures the voltage drop across each segment of a multiple segment glass fiber forming bushing and measures the current flow in the bushing. The device uses these measurements to produce error signals proportional to the difference in the set point temperature and the instantaneous temperature of each segment of the bushing. The device diverts current from each segment of the bushing whose error signal is greater than the average of the error signals for all segments of the bushing. The device also sums all error signals and passes this signal to a bushing controller which adds current to the bushing when the sum of the error signals falls below a preset value.

Abstract: The method of fabricating alumina-doped silica fibers allows the production of silica and dopant with reactions between gaseous chemical compounds. Alumina is obtained from a reaction between oxygen and a low-temperature vaporizable organometallic compound. The optical fibers produced do not present the refraction-index dip and exhibit low attenuation.

Abstract: A method for producing a glass preform comprising flame hydrolyzing a glass raw material in an oxyhydrogen flame to form glass fine particles of quartz, depositing the glass fine particles on a seed member to produce a solid or hollow cylindrical soot preform at least of a part of which contains GeO.sub.2, and heating and sintering the soot preform by introducing it in an atmosphere comprising an inert gas at least a part of which is kept at a temperature not lower than 1,600.degree. C. at an introducing rate not smaller than 3 mm/min, from the glass preform produced by which method, an optical fiber having longitudinally homogeneous composition and low attenuation of light transmission is fabricated.

Abstract: A dry etching method for selectively etching a silicon nitride having the generic formula Si.sub.x N.sub.y existing over a base of SiO.sub.2 utilizing, as the etchant gas, a mixture of a fluorohydrocarbon in which the atomic ratio of F/C is smaller than 3:1, the mixture containing 30-70% of CO.sub.2 on a flow rate basis. The presence of such a large amount of CO.sub.2 in the etchant in combination with the particular fluorohydrocarbons is effective for enhancing the selective ratio of etching between Si.sub.x N.sub.y and SiO.sub.2 and also for preventing formation of obstructive polymers of fluorocarbons.

Abstract: Apparatus and method for forming ultrapure glass rods (13) or fibers (28) from a polycrystalline rod (11) in which the method comprises the steps of heating a selected short section of the rod in the first furnace (21) to form a molten zone of the rod, heating a second selected short section of the rod in a second furnace (19) which initially is separated from the first furnace by a very short gap to form a second molten zone of the rod which initially is contiguous with and part of the first molten zone of the rod to form a single molten zone 14, and then gradually moving the first and second furnaces apart to first form a rod (13) and then, ultimately, a fiber (28), of ultrapure glass in the increasingly widening gap forming therebetween.

Abstract: A method is disclosed for making submicron openings in a substrate. A mesa is formed on the substrate by reactive ion etching techniques. A film is deposited over the entire structure and the mesa is selectively etched away to yield a submicron-sized opening in the film. Using the film as a mask, the substrate exposed thereby is reactively ion etched. An example is given for producing an emitter mask for a polycrystalline silicon base bipolar transistor.

Abstract: An apparatus for changing bushings in a glass melting furnace is disclosed. A support attached to the furnace holds the bushings beneath an opening in the forehearth. A replacement bushing is placed in the framework, translated next to the operating bushing, brought to operating thermal condition and then both bushings are translated until the replacement bushing is beneath the opening in forehearth. This eliminates the need to freeze the molten glass within the bushing.

Abstract: The invention relates to a method for manufacturing heat-resistant and/or fire-resistant fibre materials, when the employed initial material is molten slag from metal processes. According to the invention, the slag holding furnace (5) is used for achieving an essentially even and continuous molten flow from the slag smelting furnace (3) into the mineral wool furnace (6). The invention also relates to an apparatus for realizing the method, wherein the holding furnace (5) is provided with at least one control device (12) which shifts the furnace (5) between the different filling positions in order to ensure an even and continuous flow of molten material.

Abstract: A method of forming an optical shield for a laser catheter is disclosed in which a rod of light transmissive material is optically polished and inserted into a tube of similar material and fused and the distal end of the rod is cut and the assembly is optically polished at the distal end.

Abstract: The process of the invention consists in depositing a doped polycrystalline silicon layer on a silica dielectric which isolates it from the substrate. By photolithographic etching zones are defined which are intended to undergo ionic implantation for the buried channel, the zones to be protected being masked by the remaining silicon.A double silica-nitride layer is formed after the substrate has been bared in the implanted regions;Photolithographic etching of the double silica-nitride layer gives access to the first silicon level of a second doped silicon layer.Photoetching of the whole of the two silicons allows different structures to be formed in which for example the transition zone between the two dielectrics is situated under the same gate or else in which for example the transition zone is self aligned with a gate.

Abstract: A process and apparatus for spheridizing irregularly shaped minute particles, and the spheres produced thereby, in which a thin carbonaceous coating is applied to the particles in a unique manner, and in a preferred embodiment the particles are then advanced through successive fluidizing beds. The first bed has an inert atmosphere and is maintained at an elevated temperature sufficiently high to allow surface tension to shape the particles into spherical form while in a fluidized condition in the first bed. The spherical particles are then advanced through successive additional beds where they are cooled to an intermediate temperature sufficient to solidify the particles, are subjected to an oxidizing atmosphere which completely removes the coating, and are then further cooled while being maintained in a fluidized condition. The inert gaseous atmosphere within the first bed is continuously withdrawn and recycled through the system.

Abstract: This invention pertains to a method and apparatus for forming glass fibers by flowing fine streams of glass from closely spaced orifices in a feeder plate while directing a cooling gas upwardly to promote separation of the streams of glass and eliminate the tendency of the molten glass to flood at the feeder plate.

Abstract: A method is disclosed for the planarization of a semiconductor device structure by a two stage planarization process which comprises: applying a dielectric layer over a first conductive layer, spin coating an organic layer onto the first dielectric layer, etching the device in a plasma etching process to substantially remove the organic planarization layer, then etching the device in a plasma etching process which etches the exposed dielectric layer to substantially remove all of it, removing the remaining organic planarization layer, followed by the application of a second dielectric layer under bias sputter deposition conditions. The bias sputter deposition fills trenches and eliminates peaks in the remaining first dielectric layer as it builds up the second dielectric layer. The process planarizes the dielectric layer without thickness variations dependent upon conductor layer pattern density.

Abstract: A method for attaching a stud pin to a cathode ray tube panel is disclosed, which employs as a frit slurry to attach the stud pin to the cathode ray tube panel, a crystalizing solder glass, a binder and a solvent having a viscosity higher than 10 cps and a boiling point ranging from 200.degree. C. to 320.degree. C.

Abstract: A process is disclosed for producing an optical fiber comprising forming a tubular glass body having at least one doped layer, at least one concentric layer, each layer having a different index of refraction, and a hollow center. The glass body is heated until the softening point is reached, and is then drawn into a glass fiber. During drawing, a partial vacuum is maintained in the hollow center of the tubular glass body, the partial vacuum being of sufficient magnitude to reduce the evaporation of doping material from the interior of the tubular glass body and thereby effectively prevent a reduction in the index of refraction in the center of the optical fiber.