Abstract: Proposed is a frame-supported pellicle for dustproof protection of a photomask in the photolithographic patterning work for the manufacture of fine electronic devices having excellent mechanical properties and durability of the pellicle membrane against air blow and ultraviolet irradiation. The advantages of the inventive frame-supported pellicle is obtained by the use of, in place of conventional cellulose-based polymers and fluorocarbon-based resins, a norbornene-based plastic resin as the material of the pellicle membrane spread over and adhesively bonded to one end surface of a rigid frame in a slack-free fashion.

Abstract: An improvement is proposed for a frame-supported pellicle for dustproof protection of a photomask, which consists of a rigid frame and a transparent plastic membrane adhesively bonded to one end surface of the frame in a slack-free fashion, used in the photolithographic patterning work for the manufacture of fine electronic parts and devices. The improvement is obtained by coating the whole surface of the pellicle frame with a coating composition by the method of electrodeposition so as to completely solve the heretofore unavoidable problem by the dust particle deposition on the pellicle membrane during transportation and handling.

Abstract: An improvement is proposed for a frame-supported pellicle for dustproof protection of a photomask, which consists of a rigid frame and a transparent plastic membrane adhesively bonded to one end surface of the frame in a slack-free fashion, used in the photolithographic patterning work for the manufacture of fine electronic parts and devices. The improvement is obtained by providing the whole surface of the pellicle frame made from an alluminum alloy with a metallic plating layer of nickel or chromium so as to completely solve the heretofore unavoidable problem by the dust particle deposition on the pellicle membrane during transportation and handling as a consequence of dust particle formation by contacting with the inner surface of the holder case by virtue of the extremely high smoothness of the metal-plated frame surface.

Abstract: High-packing silicon nitride powder having a tap density of at least about 0.9 g/cm.sup.3 is prepared by reacting a metallic silicon powder having a mean particle size of about 1 to 10 .mu.m, a BET specific surface area of about 1 to 5 m.sup.2 /g, and a purity of at least about 99% with nitrogen in a nitrogen atmosphere containing about 5 to 20% by volume of hydrogen at about 1,350 to 1,450.degree. C., and milling the resulting silicon nitride powder in a dry attritor. The powder is moldable into a compact having a density of at least about 1.70 g/cm.sup.3, from which a sintered part having improved dimensional precision and strength is obtained.

Abstract: Proposed is a novel frame-supported pellicle for dust-proof protection of a photomask used in the photolithographic patterning work in the manufacture of semiconductor devices and the like. The frame-supported pellicle of the invention consists of a pellicle membrane made from a specific fluorocarbon-containing polymer which is adhesively bonded in a slack-free fashion to a surface of a rigid pellicle frame by means of a hot-melt adhesive which is a fluorocarbon-containing polymer of the same type as or similar to the fluorocarbon-containing polymer of the membrane so that no problems are involved in the adhesive bonding relative to the compatibility between the adhesive and the membrane which otherwise is poorly susceptible to adhesive bonding.

Abstract: An improvement is proposed in a frame-supported pellicle, i.e. a thin transparent film of a polymeric resin adhesively bonded to a frame member, used for dust-proof protection of a photomask in a photolithographic patterning work for the manufacture of electronic devices. The improvement comprises using, as the adhesive, an organopolysiloxane-based composition which comprises (a) a perfluoroalkyl-containing diorganopolysiloxane having at least two vinyl groups per molecule, (b) an organohydrogenpolysiloxane having at least one epoxy group and (c) a platinum catalyst for promoting the hydrosilation reaction between (a) and (b). As compared with conventional adhesives, a quite good adhesive bonding strength can be obtained with this adhesive even when the membrane is made from a fluorocarbon group-containing polymeric resin and the adhesive layer obtained therefrom is highly resistant against ultraviolet irradiation to ensure a long serviceable life of the pellicle.

Abstract: An improvement is proposed in the method for the preparation of a frame-supported pellicle involving a step in which a resin film for the pellicle membrane formed on the surface of a substrate plate by the solution casting method is adhesively bonded to a rigid pellicle frame and then the substrate plate is removed by separating from the resin film by pulling the substrate and the frame apart in a gaseous atmosphere of which the relative humidity is 80% or higher in contrast to the conventional procedures in which this step is conducted either in water or in a gaseous atmosphere of an air-conditioned clean room having a relative humidity never exceeding 60%. By virtue of this unique procedure, an outstandingly small number of dust particles are deposited on the pellicle membrane obtained by the removal of the substrate therefrom along with an advantage of very smooth and easy removal of the substrate not to cause slack or rupture of the membrane.

Abstract: High-packing silicon nitride powder is prepared by reacting metallic silicon powder having a mean particle size of 1 to 10 .mu.m and a purity of at least 99% directly with nitrogen for forming silicon nitride powder, milling the silicon nitride powder in a dry attritor until the tap density exceeds 0.9 g/cm.sup.3 and the content of particles having an aspect ratio of up to 3 exceeds 95% by weight, and further milling the silicon nitride powder in a wet attritor for finely dividing coarse particles having a particle size of at least 2 .mu.m. The silicon nitride powder has a tap density of at least 0.9 g/cm.sup.3 and a mean particle size of 0.4 to 0.6 .mu.m and contains at least 95% by weight of particles having an aspect ratio of up to 3 and up to 5% by weight of coarse particles having a particle size of at least 2 .mu.m. The powder is moldable into a high density compact, from which a sintered part having improved dimensional precision and strength is obtained.

Abstract: A process for the preparation of a frame-supported pellicle membrane used for dust-proof protection of a photomask in the photolithographic patterning work of, for example, semiconductor devices. An improvement is proposed for trimming of a pellicle membrane formed on a base plate and adhesively bonded to a pellicle frame to remove the extraneous portion of the membrane protruded out of the pellicle frame. Instead of the mechanical punching method for trimming, the trimming work according to the invention is performed by using a cutting device having a cutter element heated at a temperature higher than the melting point of the thermoplastic resin forming the membrane so that the membrane is trimmed by melting of the resin. Different from the conventional mechanical punching method, the trimming process of the invention is free from the problem of occurrence of dust particles deposited on the membrane to adversely affect the quality of the pattern reproduction.

Abstract: Disclosed is an X-ray transmitting frame-supported membrane of silicon nitride suitable as a mask blank of an X-ray lithographic mask having outstandingly high resistance against irradiation with high-energy radiations and high transmission of light of a wavelength of 633 nm. These very desirable properties are obtained as a consequence of the extremely low content, i.e. 1.0 atomic % or less, of hydrogen in the silicon nitride, which can be achieved as a result of the specific preparation procedure by the CVD method in which the reactant gases are silane or disilane and ammonia in a specified mixing ratio to be reacted under a specified pressure and at a specified temperature.

Abstract: A method is proposed for the preparation of a resin membrane suitable for use, for example, as a covering pellicle of a photolithographic mask for patterning of semiconductor devices in the electronic industry. The method comprises the steps of: (a) coating a continuous-length substrate with a solution of the resin by using a roller coater to form a coating layer of the resin solution; (b) drying the coating layer by evaporating the solvent to form a dry resin film on the substrate surface; and (c) peeling the resin film from the surface of the substrate, preferably, in water.

Abstract: An improvement is proposed in a frame-supported pellicle consisting of a frame member and a thin transparent polymer membrane adhesively bonded to the frame member used for dustproof covering of a photomask in a photolithograpic patterning work of electronic devices. The improvement comprises using a specific fluorocarbon group-containing organosiloxane-based polymeric composition as an adhesive for adhesively bonding the frame member and the polymer membrane. This adhesive is effective even when the polymeric membrane is formed from a fluorocarbon polymer which is hardly susceptible to adhesive bonding with conventional adhesives. In addition, the adhesive bonding by use of this specific adhesive is highly durable even under irradiation with ultraviolet light.

Abstract: A pellicle for dust-proofing of a photolithographic mask used for patterning in the manufacturing process of semiconductor devices. The drawback due to dust deposition can be greatly decreased in the use of a pellicle made from a fluorocarbon resin which is a copolymer of tetrafluoroethylene and another fluorocarbon monomer capable of introducing a cyclic perfluoroether group into the molecule when the pellicle film is rendered antistatically hydrophilic, for example, by a plasma treatment.

Abstract: Disclosed is a method for dust-proofing of a photomask in the photolithographic processing of electronic devices, e.g., LSIs and liquid-crystal display panels, in which the photomask is covered with a pellicle having a frame-supported light-transmitting membrane made from a polyvinyl alcohol modified by silylating the hydroxy groups of the polyvinyl alcohol with triorganosilyl groups of the formula R.sub.3 Si--, in which R is a monovalent hydrocarbon group, e.g., alkyl, in a degree of substitution of at least 40%. The membrane of the pellicle is highly transparent to light of short wavelength in the ultraviolet region and excellently durable under prolonged irradiation with ultraviolet light not to cause yellowing or mechanical breaking.

Abstract: An X-ray permeable membrane for an X-ray lithographic mask consisting of an inorganic thin film obtained by the sputtering method using a target and consisting of silicon carbide and carbon, said target consisting of silicon carbide and carbon in a molar ratio of 99.9:0.1 to 70:30, having a transmission of at least 37% at a light wavelength of 633 nm and a tensile strength of 1.times.10.sup.8 to 1.times.10.sup.10 dyn/cm.sup.2, and the membrane consisting of a silicon carbide constituted form silicon and carbon in a molar ratio in the range form 50.1:49.9 to 49.9:50.1.

Abstract: Disclosed is an X-ray-permeable membrane for X-ray lithographic mask for fine patterning in the manufacture of semiconductor devices having good transparency to visible light and exhibiting excellent resistance against high-energy beam irradiation. The membrane has a chemical composition expressed by the formula SiC.sub.x N.sub.y and can be prepared by the thermal CVD method in an atmosphere of a gaseous mixture consisting of gases comprising, as a group, the elements of silicon, carbon and nitrogen such as a ternary combination of silane, propane and ammonia.

Abstract: An X-ray transmitting homogeneous membrane suitable for use in a mask for X-ray lithography is disclosed which compositely consists of silicon carbide and silicon nitride in a specified molar proportion. The membrane can be prepared by depositing a film of a homogeneous composite of silicon carbide and silicon nitride on a silicon wafer as a substrate by sputering using a target which is also a sintered composite material of silicon carbide and silicon nitride. As compared with membranes of silicon carbide alone or silicon nitride alone, the inventive membrane is advantageous in respect of the high resistance against high-energy irradiation, chemicals and moisture as well as in respect of high visible-light transmission, especially, when the tensile stress within the membrane is in a specified range.

Abstract: Proposed is a high-precision X-ray lithographic mask blank with reinforcement free from warping or distortion. The mask blank is an integral body comprising: (a) a frame made from a silicon wafer; (b) a membrane of an X-ray permeable material such as silicon carbide adhering to and supported by one surface of the frame; and (c) a reinforcing member made from a single crystal of silicon adhesively bonded to the other surface of the frame with (d) a layer of silicon oxide intervening between the frame and the reinforcing member. The mask blank can be prepared in a process of first forming a layer of silicon oxide on the surface of the silicon wafer and/or reinforcing member prior to deposition of the X-ray permeable film on the silicon wafer and heating them together at a temperature of 800.degree. C. or lower while they are in direct contact with each other with the silicon oxide layer intervening therebetween.

Abstract: In a process for the deposition of a film of an inorganic substance such as silicon carbide on the surface of a substrate such as a silicon wafer by the method of sputtering, as in the process for the preparation of a membrane to serve as an X-ray lithographic mask, using a target disc and a substrate disc held in parallel to each other, uniformity in the internal stress of the deposited film can be improved by displacing the target or the substrate relative to each other during the sputtering procedure in the direction parallel to the surface of the target or substrate in a distance of at least 1 mm.

Abstract: The curable silicone composition of this invention contains as essential components, (A) a copolymer comprised of vinylidene fluoride and/or tetrafluoroethylene component(s), (B) an organopolysiloxane having in its molecule aliphatic unsaturated groups and a fluorine-containing substituent, (C) an organohydrogenpolysiloxane, and (D) a catalyst for addition reaction. This composition can be effectively used as a release agent.