Abstract:
A circuit board includes an electrical insulator layer formed of a reinforcer sheet (101) with density distribution in its in-plane direction, an electrical conductor filled in a plurality of inner via holes provided in the electrical insulator layer in its thickness direction, and a wiring layer connected to the electrical conductor. The inner via holes (104) provided in a high-density portion of the reinforcer sheet (101) are formed to have a smaller cross-section than the inner via holes (103) provided in a low-density portion of the reinforcer sheet. In this manner, it is possible to provide a circuit board that can achieve a high-density wiring and an inner via connection resistance with less variation, when a base material including a reinforcer sheet with density distribution in its in-plane direction such as a glass cloth formed of warps (102b) and wefts (102a) is used for an insulator layer.
Abstract:
A process for manufacturing a multi-layer printed wire board, also referred to as a multilayer, comprising at least two electrically insulating substrates with electrically conductive traces or layers provided on at least three surfaces thereof, in which process, by means of lamination under pressure, a cured basic substrate based on a UD-reinforced synthetic material, provided on either side with traces, is combined with and bonded to a back-up substrate, wherein during the laminating process the back-up substrate is added to the basic substrate, the base substrate and the back-up substrate comprising a UD-reinforced cured core layer, the base substrate having been provided at least on the side facing the back-up substrate with a still plastically deformable (flowable) adhesive layer, and such a pressure is exerted on the laminate as to bring said back-up substrate into contact or practically into contact with the conducting traces of the basic substrate, and the space between these traces is filled with the adhesive material, so bonding the basic substrate and the back-up substrate.
Abstract:
A warp-free laminate is produced by winding a first set of strands or filaments (34) about a flat mandrel with a second set of strands (36) being wound transverse to the first set. The two sets may be perpendicular to each other. The filaments are maintained under a controlled tension while being impregnated with a resin and during subsequent cure of the resin. In order to permit the formation of a warp-free product, the winding pattern is such that it forms a mirror image about a neutral axis or plane of symmetry. The winding pattern may be chosen to provide interstices in a predetermined pattern permitting punching out or high speed drilling of hole openings (106, 108, 110, 112, 114) for subsequent printed circuit applications.
Abstract:
The invention relates to a method of manufacturing a composite laminate, preferably a cross-ply laminate, in which process unidirectionally oriented (UD) fibres (3) are provided with matrix material (7) and, together with a pre-formed non-flowing UD composite or cross-ply laminate, passed through a laminating zone (13) in layers of at least two different orientational directions. More particularly, the invention relates to the manufacture of composite material which is pre-eminently suited to be used as a supporting substrate for printed wire boards. The method according to the invention is directed in particular to the utilisation of a double belt press, both for making the pre-formed non-flowing UD composite and for the manufacture of the final laminate. The invention also comprises printed wire boards (PWBs) and multilayer PWBs.
Abstract:
Prepregs (124), laminates (120, 122), printed wiring board structures and processes for constructing materials and printed wiring boards that enable the construction of printed wiring boards with improved thermal properties. In one embodiment, the prepregs include substrates impregnated with electrically and thermally conductive resins (132). In other embodiments, the prepregs have substrate materials that include carbon. In other embodiments, the prepregs include substrates impregnated with thermally conductive resins. In other embodiments, the printed wiring board structures include electrically and thermally conductive laminates that can act as ground and/or power planes.
Abstract:
The present invention relates to a unidirectional glass fabric produced with continuous yarn (2, 3) which is twisted, plied or has zero twisting turns, with different gram weights and interlaced with thin glass yarns (3) as a stabilizing binding, use thereof in the manufacture of printed circuits and in numerous other industrial applications, and a method for the manufacture thereof.
Abstract:
Die Erfindung bezieht sich auf Basismaterialien und Prepregs aus Epoxidharzglasfasergewebe zur Herstellung von Leiterplatten. Die Dimensionsstabilität von Basismaterial und Prepreg ist je nach Typ unterschiedlich. Diese Unterschiedlichkeit wird durch Temperprozesse über den Glasumwandlungspunkt und Vorhaltewerte bei den Druckwerkzeugen zu kompensieren versucht. Durch die Erfindung soll die Dimensionsstabilität derartiger Materialien verbessert werden. Durch die Verwendung von unidirektionalen Geweben, bei denene das Verhältnis der Glasstränge in Kett- und Schußrichtung oder umgekehrt größer 70:30 und/oder das Verhältnis der Garngewichte in Kett- und Schußrichtung oder umgekehrt größer 1,5:1 beträgt, und/oder als Webart Satinbindung realisiert wird, wird eine deutliche Verbesserung der Dimensionsstabilität bei nur geringfügig erhöhten Kosten erzielt.
Abstract:
A multilayer printed circuit board in which multiple layers of a composite material (16), fabricated by the lay-up of an aramid fiber tape (22,26,28,24), are employed to provide a circuit board with a desired coefficient of thermal expansion.
Abstract:
A composite containing high purity crystalline ceramic fibers in a polymeric matrix, suitable for use as a microelectronic device package or circuit board. The composite exhibits high thermal conductivity, and low coefficients of thermal expansion in-plane, and moderate thermal conductivities and low dielectric constants out-of-plane.