Abstract: The defluxing agent for flux residue after soldering contains an acid (preferably an organic acid, and particularly an acid stronger than abietic acid; for example, acrylic acid, acetic acid, propionic acid, benzoic acid) and an organic solvent (for example, xylene, benzyl acetate, methyl .alpha.-hydroxyisobutyrate, cyclohexanone, methyl .beta.-methoxyisobutyrate), and if necessary it further contains a monohydric alcohol, a surfactant and a corrosion inhibitor. Rinsing is preferably performed after the cleaning, using a solvent which is miscible with the defluxing agent, in order to completely remove the acid. There is also disclosed a cleaning apparatus which may be generally used for this and other cleaning.

Abstract: A method for fabricating solder bumps onto a semiconductor chip. A solder ball forming member having a flat surface and a plurality of cavities arranged on the flat surface in a predetermined pattern is prepared. The cavities are then filled with a solder paste, and the solder ball forming member is heated to a temperature higher than the melting point of the solder so that the molten solder powder in the solder paste form solder balls due to surface tension. The semiconductor chip is then moved toward the solder ball forming member to transfer the heated solder balls from the solder ball forming member to the semiconductor chip.

Abstract: Disclosed are a method of and an apparatus for cleaning a plurality of nozzles of an ink jet head. This cleaning method comprises a step of covering a nozzle surface formed with the plurality of nozzles with a cap; a step of depressurizing an air space formed between the nozzle surface and the cap by use of a depressurizing element to suck the inks from the nozzles; a step of stopping the depressurization by the depressurizing element; a step of keeping the nozzle surface covered with the cap so that the inks jetted from the nozzles due to the depressurization wet-spread over the entire nozzle surface by a capillary force; and a step of retracting the cap from the nozzle surface. Further, in this cleaning apparatus, a contact angle .theta.1 between the ink and the cap internal surface and a contact angle .theta.2 between the ink and the nozzle surface are set to 90.degree. or smaller and also set such that .theta.2 is not greater than .theta.1.

Abstract: The defluxing agent for flux residue after soldering contains an acid (preferably an organic acid, and particularly an acid stronger than abietic acid; for example, acrylic acid, acetic acid, propionic acid, benzoic acid) and an organic solvent (for example, xylene, benzyl acetate, methyl .alpha.-hydroxyisobutyrate, cyclohexanone, methyl .beta.-methoxyisobutyrate), and if necessary it further contains a monohydric alcohol, a surfactant and a corrosion inhibitor. Rinsing is preferably performed after the cleaning, using a solvent which is miscible with the defluxing agent, in order to completely remove the acid. There is also disclosed a cleaning apparatus which may be generally used for this and other cleaning.

Abstract: A method for fabricating a semiconductor device using a solder ball forming plate having cavities. The plate is made from a silicon plate having a flat surface in a <110> crystallographic plane, and an orientation flat in a <1-11> crystallographic plane. The cavities are formed on the flat surface of the plate by etching, using a mask having openings in the shape of rhombus arranged such that one side of the rhombus is generally parallel to the <1-11> crystallographic plane. As a result, the cavities having wedge-shaped bottom are formed. The cavities are then filled with a solder paste and are heated to form solder balls in the cavities while the plate in an inclined position. The solder balls are then transferred from the plate to a semiconductor chip.

Abstract: The surface of a copper layer in a circuit board is irradiated with a beam, and the degree of progress of oxidation of the surface of the copper layer is determined by taking advantage of the resultant reflected beam (for example, an intensity or a hue of a reflected beam). Then, the step of coating a resist is carried out only when the thickness of the copper oxide film is not more than about 10 nm. Alternatively, the step of coating a resist may be carried out after removal or reduction of the oxide film or cladding of the oxide film with copper.The present invention enables occurrence of peeling of the resist or dive of plating to be prevented in the step of effecting selective etching or plating of a copper layer in a circuit board using a resist pattern as a mask.

Abstract: A polymer dispersed liquid crystal display device having a liquid crystal layer inserted between opposed glass plates and comprising a layer of resin and liquid crystal capsules dispersed in the resin. The liquid crystal capsules are substantially uniformly distributed all over the liquid crystal panel, even if a black matrix and bus lines provided in the glass plates may act as a shading layer when an ultraviolet light is irradiated to cure the resin and to form the liquid crystal capsules. The uniformly distributed liquid crystal capsules can be obtained by the manufacturing method comprising the step of irradiating the ultraviolet light obliquely to a surface of the glass plate having the shading layer for curing the resin material.

Abstract: A method for removing copper oxide on a surface of a copper film is comprising the steps of treating the surface of the copper film with acid, neutralizing the surface of the copper film treated with acid, and washing the neutralized surface of the copper film.

Abstract: Electrophotographic printer toner carriers comprising a core material and a fluorinated polyimide resin coated on the core material, the fluorine content of the fluorinated polyimide resin being 5 to 60% by weight of the fluorinated polyimide resin.

Abstract: An excimer laser ablation processing for forming via holes in a resin film by irradiation of an excimer laser wherein, the emission of light caused during the decomposition of the resin during the processing is detected, its intensity is measured, and the endpoint of the processing is judged or a comparison is made of the positions of light emission and the design positions for processing to examine for the presence of defects. Provision is made of a means for measuring the intensity and a means for judging the endpoint of the processing from the changes in the intensity of light emission during the processing.

Abstract: This invention relates to an insulating material for a wiring substrate and to a method of producing a multi-layered wiring substrate, and is directed to put into practical application a multi-layered wiring substrate suitable for processing high speed signals. The production method of the multi-layered wiring substrate of this invention uses an insulating material prepared by allowing voids of a porous perfluorocarbon polymer film to be impregnated with a thermosetting resin containing a benzocyclobutene ring, and thermally setting the resin, and comprises laminating alternately a wiring layer and an insulating layer made of the insulating material for the wiring substrate on a rigid support substrate.

Abstract: An equipment for excimer laser ablation machining provided a laser (11), a main body (14) housing a mirror (12) for reflecting an ultraviolet ray emitted by the laser and an optical system (13) for arranging the ultraviolet ray to a parallel ray, and a means (15) for moving the relative position of an object to be machined and the parallel ray, the means (15) being a supporter of an object to be machined and having a means (16) for arranging a dielectric mirror mask (7), leaving a space of 0.1 mm through 50 mm, preferably 0.1 mm through 1 mm, between the object to be machined and the dielectric mirror mask (7), the equipment to be employed specifically for producing a via hole of a multi-layered circuit board, and a method for excimer laser ablation machining conducted by employing the foregoing equipment.

Abstract: A liquid crystal display element comprising a liquid crystal composition having an optically active compound as at least one constituent and showing a cholesteric phase in a bulk state, wherein the liquid crystal composition is arranged between substrates, at least one of which is provided with a transparent electrode, so that long axes of individual liquid crystal molecules are in parallel to one another and are oriented in the same direction as the surfaces of the substrates, and the long axes of the molecules are uniformly aligned in parallel, vertically or inclined to the surfaces of the substrates, wherein the gap d (.mu.m) between the substrates and the size p (.mu.m) of the helical pitch shown by the cholesteric phase liquid crystal at room temperature when an electric field is not applied satisfy the following relationships:d/p.gtoreq. 1.

Abstract: A method of and apparatus for forming a volume type phase hologram comprising the steps of, after exposure of a holographic material comprising a polymeric matrix having a radiation active substance associated therewith to an interference pattern of radiation, dipping the pattern-wise exposed holographic material in a swelling solution consisting of a first solvent which can act as a good solvent for the polymer of the matrix and a second solvent which can act as a poor solvent for the polymer and has a higher boiling point than that of the first solvent, and then pulling the swollen holographic material up from the swelling solution, whereby uniformly developed holograms having a large size and high qualities can be easily produced by a simple production process.

Abstract: A liquid crystal display element comprising a liquid crystal composition having an optically active compound as at least one constituent and showing a cholesteric phase in a bulk state, wherein the liquid crystal composition is arranged between substrates, at least one of which is provided with a transparent electrode, so that long axes of individual liquid crystal molecules are in parallel to one another an are oriented in the same direction as the surfaces of the substrates, and the long axes of the molecules are uniformly aligned in parallel, vertically or inclined to the surfaces of the substrates, wherein the gap d (.mu.m) between the substrates and the size p (.mu.m) of the helical pitch shown by the cholesteric phase liquid crystal at room temperature when an electric field is not applied satisfy the following relationships:d/p.gtoreq.1.

Abstract: A method of and apparatus for forming a volume type phase hologram comprising the steps of, after exposure of a holographic material comprising a polymeric matrix having a radiation active substance associated therewith to an interference pattern of radiation, dipping the pattern-wise exposed holographic material in a swelling solution consisting of a first solvent which can act as a good solvent for the polymer of the matrix and a second solvent which can act as a poor solvent for the polymer and has a higher boiling point than that of the first solvent, and then pulling the swollen holographic material up from the swelling solution, whereby uniformly developed holograms having a large size and high qualities can be easily produced by a simple production process.

Abstract: In a process for preparing an ink for a drop-on-demand type ink jet printer, sonic vibration is applied to the ink which is being prepared or has been prepared so that a gas entrained into the ink by incorporation of a dye therein can be removed. This ink can be stably injected through a recording head, even if the size of the head is made smaller to increase the atomizing frequency, or the recording speed.

Abstract: A bright and large information capacity projection-type multi-color liquid crystal display is realized by a display device which includes a liquid crystal panel having a plurality of layers of cholesteric-nematic phase transition type liquid crystals having a positive dielectric anisotropy and phase transition hysterisis when a voltage is applied. The liquid crystals are driven to be in homeotropic and focalconic textures which are maintained when at a certain voltage is applied thereto. A desired color of the projected display can be obtained by selecting a thickness of the liquid crystal layer and a refractive index anisotropy of the liquid crystal of the liquid crystal layers.

Abstract: A cholesteric-nematic phase transition type liquid crystal with positive dielectric anisotropy is used in a projection type liquid crystal display device. This allows a bright and high information contents display with a compact, light, and low cost device and allows machinery input and thus simultaneous display at remote places, such as remote conference rooms or remote notice boards, in bright locations.

Abstract: A visible ray-recording hologram material comprising a polymer containing a carbazole ring, iodoform, and an aromatic colorant having a fused ring system. This material enables recording with rays having a wavelength of 450 to 550 nm.