Abstract: A flame retardant is included in a resin phase, and the flame retardant has a maximum number frequency in a range of 1 ?m or less when a particle size distribution is evaluated by dividing a particle size into 1 ?m increments. The resin phase includes inorganic particles, and the inorganic particles have a maximum number frequency in a range of 0.5 ?m or less when the particle size distribution is evaluated by dividing the particle size into 0.5 ?m increments. The flame retardant has an average particle size larger than the average particle size of inorganic particles. The number frequency of the flame retardant and the inorganic particles, respectively, decreases with increasing the particle size.

Abstract: A laminated uncured sheet of the present disclosure has a structure in which resin sheet layers and resin layers are alternately laminated and a through hole penetrating in the laminating direction is formed, wherein the resin sheet layers are formed with a thermosetting resin composition containing a thermosetting resin as a main component, the resin layers are formed with a thermoplastic resin composition containing a thermoplastic resin, and the thermoplastic resin composition is adhered to the inner wall surface of the resin sheet layer part in the through hole.

Abstract: A flame retardant is included in a resin phase, and the flame retardant has a maximum number frequency in a range of 1 ?m or less when a particle size distribution is evaluated by dividing a particle size into 1 ?m increments. The resin phase includes inorganic particles, and the inorganic particles have a maximum number frequency in a range of 0.5 ?m or less when the particle size distribution is evaluated by dividing the particle size into 0.5 ?m increments. The flame retardant has an average particle size larger than the average particle size of inorganic particles. The number frequency of the flame retardant and the inorganic particles, respectively, decreases with increasing the particle size.

Abstract: A laminated uncured sheet of the present disclosure has a structure in which resin sheet layers and resin layers are alternately laminated and a through hole penetrating in the laminating direction is formed, wherein the resin sheet layers are formed with a thermosetting resin composition containing a thermosetting resin as a main component, the resin layers are formed with a thermoplastic resin composition containing a thermoplastic resin, and the thermoplastic resin composition is adhered to the inner wall surface of the resin sheet layer part in the through hole.

Abstract: Dielectric ceramics comprising a diopside oxide crystal phase, at least one kind of crystal phase selected from the group consisting of a quartz crystal phase and a composite oxide crystal phase containing Ti and Mg or Zn, and a glass phase of an amount of not larger than 30% by weight, said dielectric ceramics having a coefficient of thermal expansion of not smaller than 5.5 ppm/° C. at room temperature to 400° C. and a dielectric loss of not larger than 30×10−4 at 60 to 77 GHz. The ceramics can be obtained by the co-firing with a low-resistance metal such as copper or silver, and can be advantageously used for the production of wiring boards to which the signals of particularly high frequencies are applied. The ceramics has a large coefficient of thermal expansion which can be brought close to the coefficient of thermal expansion of the semiconductor element such as of GaAs or of the printed board.

Abstract: A structure for mounting a wiring board in which the wiring board including a ceramics insulating board, metallized wiring layers arranged on said insulating board, and a plurality of connection terminals mounted on said insulating board and electrically connected to said metallized wiring layer, is placed on a mother board having wiring conductors formed on the surface of an insulator which contains an organic resin, and the connection terminals of said wiring board are connected by brazing to the wiring conductors of said mother board, wherein a value F1 defined by the following formula (1):F1=L.times..DELTA..alpha./H.sup.2 (1)wherein L is a distance (mm) between the two connection terminals which are most separated away from each other among a plurality of connection terminals mounted on said insulating board, .DELTA..alpha. is a difference in the coefficient of thermal expansion (ppm/.degree. C.) between the insulating board of said wiring board and said mother board at 40 to 400.degree. C.

Abstract: In a circuit board obtained by providing a metallized layer of wiring on the surface or interior of an insulation substrate, the insulation substrate is, for example, a multi-layer circuit board or a package for semiconductor element, the insutating substrate obtained from a sintered body having a linear expansion coefficient of 8 to 18 ppm/.degree. C. at 40.degree. to 400.degree. C. which is prepared by sintering a molded body containing 20 to 80% of a glass having a liner expansion coefficient of 6 to 18 ppm/.degree. C. at 40.degree. to 400.degree. C. and 80 to 20% of a filler having a linear expansion coefficient of at least 6 ppm/.degree. C.