Abstract: A method for producing printed wiring boards comprises the steps of perforating through holes at predetermined positions in an adhesive insulator sheet, filling the through holes with a conductive material such as a conductive paste or metal balls, transferring conductive wiring patterns that have been formed on surfaces of releasable supporting sheets onto the surfaces of the adhesive insulator sheet by heat and pressure. Simultaneously, interlayer via-connections are performed by means of the conductive material filled into the through holes.

Abstract: In a wiring board, predetermined wiring patterns which are formed on both sides of an insulation substrate are electrically connected by an electrically conductive material provided in through holes formed through the insulation substrate. The insulation substrate is composed of a resin impregnated fibrous sheet and a heat resistant film. The present invention solves the problems of the wiring board which are caused by irregularities on the surface of the resin impregnated fibrous sheet. The problems include insufficient adhesion strength between the wiring pattern and the insulation substrate or the limitation of fineness of the wiring pattern due to the irregularities on the surface of the printed wiring board which are formed upon the thermocompression bonding process.

Abstract: A method for producing printed wiring boards comprises the steps of perforating through holes at predetermined positions in an adhesive insulator sheet, filling the through holes with a conductive material such as a conductive paste or metal balls, transferring conductive wiring patterns that have been formed on surfaces of releasable supporting sheets onto the surfaces of the adhesive insulator sheet by heat and pressure. Simultaneously, interlayer via-connections are performed by means of the conductive material filled into the through holes.

Abstract: A printed wiring board includes at least one insulator sheet having through holes filled with conductive material and a conductive wiring pattern. The wiring pattern is embedded in the insulator sheet so that an upper surface of the wiring pattern and surrounding portions of the insulator sheet form a flat surface. The insulator sheet may be made from a glass-epoxy prepreg or of a polyester or polyimide sheet coated with an adhesive or glue. The wiring pattern can be transferred to the insulator sheet from a surface of a releasable supporting sheet.

Abstract: A multilayer wiring board comprising a mother wiring board and a carrier wiring board, in which all of the composing layers have IVH structure. The mother wiring board (11) is formed in the manner that a plurality of resin-impregnated-fiber-sheets having mother wiring layers (13) and first inner-via-hole conductors (14) for connecting the wiring layers (13) each other are laminated. The mother wiring board (11) comprises a base board (11a) and container board (11b) having an opening for forming a cavity (15). The carrier wiring board (16) has lands (17) for mounting LSI bare chips, wirings (18), a plurality of carrier-board-wiring-layers (19) and second inner-via-hole conductors (20) for connecting the wiring layers (19) each other.

Abstract: A stress relaxation type electronic component which is to be mounted on a circuit board, wherein a stress relaxation mechanism member is disposed on a surface of said electronic component, said surface being on a side of a connection portion where said electronic component is to be connected to said circuit board, and said stress relaxation mechanism member is electrically conductive.

Abstract: In a wiring board, predetermined wiring patterns which are formed on both sides of an insulation substrate are electrically connected by an electrically conductive material provided in through holes formed through the insulation substrate. The insulation substrate is composed of a resin impregnated fibrous sheet and a heat resistant film. The present invention solves the problems of the wiring board which are caused by irregularities on the surface of the resin impregnated fibrous sheet. The problems include insufficient adhesion strength between the wiring pattern and the insulation substrate or the limitation of fineness of the wiring pattern due to the irregularities on the surface of the printed wiring board which are formed upon the thermocompression bonding process.

Abstract: A multilayer wiring board comprising a mother wiring board and a carrier wiring board, in which all of the composing layers have IVH structure. The mother wiring board (11) is formed in the manner that a plurality of resin-impregnated-fiber-sheets having mother wiring layers (13) and first inner-via-hole conductors (14) for connecting the wiring layers (13) each other are laminated. The mother wiring board (11) comprises a base board (11a) and container board (11b) having an opening for forming a cavity (15). The carrier wiring board (16) has lands (17) for mounting LSI bare chips, wirings (18), a plurality of carrier-board-wiring-layers (19) and second inner-via-hole conductors (20) for connecting the wiring layers. (19) each other.

Abstract: A multilayer wiring board comprising a mother wiring board and a carrier wiring board, in which all of the composing layers have IVH structure. The mother wiring board (11) is formed in the manner that a plurality of resin-impregnated-fiber-sheets having mother wiring layers (13) and first inner-via-hole conductors (14) for connecting the wiring layers (13) each other are laminated. The mother wiring board (11) comprises a base board (11a) and container board (11b) having an opening for forming a cavity (15). The carrier wiring board (16) has lands (17) for mounting LSI bare chips, wirings (18), a plurality of carrier-board-wiring-layers (19) and second inner-via-hole conductors (20) for connecting the wiring layers (19) each other.

Abstract: A method for producing printed wiring boards comprises the steps of perforating through holes at predetermined positions in an adhesive insulator sheet, filling the through holes with a conductive material such as a conductive paste or metal balls, transferring conductive wiring patterns that have been formed on surfaces of releasable supporting sheets onto the surfaces of the adhesive insulator sheet by heat and pressure. Simultaneously, interlayer via-connections are performed by means of the conductive material filled into the through holes.

Abstract: A nonwoven fabric cloth substrate for printed wiring boards containing aromatic polyamide fibers and having a 0.7-1.0 dynamic elastic modulus ratio (E' (250.degree. C.)/E' (30.degree. C.)) and a 0.05 or less loss tangent (Tan .delta.) peak value at 30-250.degree. C., and a prepreg and a printed wiring board using the nonwoven fabric cloth substrate.

Abstract: To address the problem of difficulty of making compatible flame retarding property and electrical and mechanical characteristics in conventional printed interconnection substrates, the present invention employs, in a substrate for printed circuit board of which the insulating material comprises a thermosetting resin composition comprising an epoxy resin main component and a curing agent, an epoxy resin containing a brominated phenol novolac type epoxy resin having a biphenyl skeleton as the main component or a curing agent containing a brominated phenol novolac type curing resin. It provides a substrate for printed circuit board which has an extremely high flame retarding property and a superior heat resistance and humidity resistance, as well as a high insulating reliability and a superior high frequency characteristic.

Abstract: A nonwoven fabric cloth substrate for printed wiring boards containing aromatic polyamide fibers and having a 0.7-1.0 dynamic elastic modulus ratio (E' (250.degree. C.)/E' (30.degree. C.)) and a 0.05 or less loss tangent (Tan.delta.) peak value at 30.degree.-250.degree. C., and a prepreg and a printed wiring board using the nonwoven fabric cloth substrate.

Abstract: A magnetic recording medium including a non-magnetic polymeric support and a magnetic layer on the non-magnetic polymeric support. The magnetic layer is positioned to be in contact with a record/playback head and includes ferromagnetic powder, abrasive material and binder resin, with at least 40 parts by weight of the abrasive material per 100 parts by weight of the ferromagnetic powder. The ferromagnetic powder has a saturation magnetization .sigma.s of 80 emu/g or more and long axis length of 0.25 .mu.m or less.

Abstract: In the magnetic recording medium, the non-magnetic substrate has at least one under-coat layer including the flake powder of non-magnetic material on its surface, thereby splendid property of running durability and electromagnetic transducing characteristics is achieved in spite of thinning the total thickness of the magnetic recording medium.

Abstract: Tape-shaped magnetic medium has a magnetic layer composed of compound powders of hexagonal and spinel ferrites and is designed so that the magnetic layer and the nonmagnetic base film, that is either a PEN film or an aromatic polyamide film, have specified ratios of their thicknesses and their Young's module for the longitudinal directions as well as for the transverse directions.

Abstract: In the magnetic recording medium, the non-magnetic substrate has an under-coat layer including the first flake powder of non-magnetic material on its surface and further has a back-coat film including the second flake powder of non-magnetic material on the opposite face on the non-magnetic substrate to the one face coated by the magnetic film; thereby splendid property of running durability and electromagnetic transducing characteristics is achieved in spite of thinning the total thickness of the magnetic recording medium.

Abstract: A magnetic recording medium comprising a non-magnetic support, a magnetic layer on one surface of said non-magnetic support, a back coating layer on the other surface of said non-magnetic support and a primer layer containing acicular hexagonal ferrite magnetic powder between said non-magnetic support and at least one of said magnetic layer and said back coating layer, which is used with a video recorder fitted for high density recording and in particular, which copes with prolongation of a recording time.

Abstract: Of disk-shaped or tape-shaped magnetic recording media composed of non-magnetic supports and magnetic layers which, formed on the supports, contain a magnetic powder and a binder for it, the magnetic recording medium having superior electro-magnetic conversion characteristics, high durability, and high reliability has been obtained as a result of improving the abrasion resistance of the magnetic layer without impairing the surface smoothness thereof, by incorporating a non-magnetic inorganic powder of at least 5 Mohs hardness which has a dendrite or chain structure.

Abstract: A magnetic recording medium which comprises a support and a magnetic layer formed on opposite sides of the support and comprised of a ferromagnetic fine powder and an non-magnetic powder of an abrasive both dispersed in a resin binder. The non-magnetic powder consists essentially of a first non-magnetic inorganic powder having an average particle size of from 0.01 to 1.0 .mu.m and a second non-magnetic inorganic powder having an arborescent or chain-like structure and an average particle size of from 0.03 to 2.0 .mu.m. The first and second powders is present at a mixing ratio by weight of 8:2 to 2:8.