Abstract: An optical semiconductor element mounting package that has good adhesion between the resin molding and the lead electrodes and has excellent reliability is provided, as well as an optical semiconductor device using the package is also provided. The optical semiconductor element mounting package having a recessed part that serves as an optical semiconductor element mounting region, wherein the package is formed by integrating: a resin molding composed of a thermosetting light-reflecting resin composition, which forms at least the side faces of the recessed part; and at least a pair of positive and negative lead electrodes disposed opposite each other so as to form part of the bottom face of the recessed part, and there is no gap at a joint face between the resin molding and the lead electrodes.

Abstract: A substrate for mounting optical semiconductor elements is provided, including a base substrate having an insulating layer and a plurality of wiring circuits formed on the upper face of the insulating layer, and having at least one external connection terminal formation opening portion which penetrates the insulating layer and reaches the wiring circuits; and an optical reflection member, which is provided on the upper face of the base substrate, and which forms at least one depressed portion serving as an area for mounting an optical semiconductor element.

Abstract: A substrate for mounting a semiconductor chip having bumps using an adhesive thereon, said substrate being, for instance, provided with an insulating coating having an opening in the semiconductor chip mounting area so that the wiring conductors will not be exposed to the substrate surface near the boundary of the semiconductor chip mounting area, is improved in connection reliability and has high mass productivity.

Abstract: An insulating varnish comprising a resin component, electrical insulating whiskers, and if necessary, one or more additives such as an ion adsorbent, and/or an organic reagent for preventing injury from copper, produced by adding the additives to the resin component and the whiskers, or filtering the whiskers, or milled by using a beads mill or a three-roll mill, or the like, is excellent for producing a multilayer printed circuit board having high wiring density, high reliability and excellent other electrical properties.

Abstract: A multilayer printed circuit board small in interlayer thickness, capable of fine wiring, minimized in IVH and BVH diameters, high in strength and also excellent in wire bonding workability can be produced by a process comprising the steps of coating a thermosetting resin varnish compounded with electrically insulating whiskers on a roughened side of a copper foil, semi-curing the resin by heating to form a thermosetting resin layer, integrally laminating it on an interlayer board in which plated through-holes and conductor circudits have been formed, and roughening the cured thermosetting resin layer on the via hole wall surfaces with a roughening agent.

Abstract: A metal foil for printed wiring boards comprising a first copper layer to be adhered to a resin, a second copper layer having a sufficient strength as a metal layer and a nickel-phosphorus alloy layer containing 1.1% by weight or more of phosphorus formed between the first and second copper layers is suitable for producing printed wiring boards having excellent heat resistance, particularly during production procedures.

Abstract: A process for producing a wiring board involves laminating a metal foil on both sides of an insulating substrate not completely cured, followed by pressing with heating; drilling holes in the resulting laminate for connecting circuits therein; removing portions of the metal foils in narrow areas around the holes to form hollow portions in the metal foils; and filling a flowable electroconductive substance in the holes and the hollow portions.

Abstract: A wiring board comprising one or more inner layer circuit substrates and outer circuit layers formed from metal foil layers on both sides of said dinner layer circuit substrates via prepregs, said inner layer circuit substrate comprising an insulating layer and metal foil layers formed on both sides of said insulating layer, at least one inner layer circuit substrate or said outer circuit layers or both having hollow portions in the metal foil layer filled with an electroconductive substance, said wiring board having one or more through-holes at least in the hollow portions and filled with the electroconductive substance, has high reliability and a high wiring density.

Abstract: A metal foil for printed wiring boards comprising a first copper layer to be adhered to a resin, a second copper layer having a sufficient strength as a metal layer and a nickel-phosphorus alloy layer containing 1.1% by weight or more of phosphorus formed between the first and second copper layers is suitable for producing printed wiring boards having excellent heat resistance, particularly during production procedures.