Abstract:
Embodiments of the present invention are directed to methods and structures providing completely filled electrical interconnections, or vias, that are disposed through a surface land mounting area, or pad, on a dielectric substrate (104). A via (100) includes a first conducting layer (106) on the inner surface (102c) of a via hole. The via hole is filled with a thermally conductive material (110) with a desired viscosity and/or thixotropic ratio. The via fill material may be a metal powder in an epoxy matrix. The dielectric substrate may be used in rigid and/or flexible circuit components such as PWBs. High levels of surface land co-planarity, or surface flatness for pads on such substrates may be achieved by the use of conductive layers formed by immersion processes. Aspects of the invention may provide reduced amounts of lead (Pb) or eliminate lead altogether from a substrate.
Abstract:
A semiconductor device capable of dealing with the reduction of the pitch of wires on a semiconductor element, an increase in the chip mounting density and the reduction of the thickness of a semiconductor device, and having excellent adherence between an insulating resin used for sealing a semiconductor element and a film carrier, and a high reliability. Referring to Fig. 1, conductor circuits 5 are buried so as not to be exposed to both surfaces 6a, 6b of an insulating layer 6, and a pair of conductive passages 7, 8 are formed so as to extend from both surfaces 5a, 5b of the conductor circuits 5 in a staggered manner with respect to the direction of the surfaces of the conductor circuits 5. The conductive passages 7, 8 are connected to bumps 9, 10, that is, the conductor circuits 5 and bumps 9, 10 are electrically connected through the conductive passages 7, 8. The bumps 9 formed on one end of one conductive passage in a film carrier 2 are connected electrically to electrodes 12 of a semiconductor element 3, and the film carrier 2 supports the semiconductor element 3. An insulating resin layer 4 is formed so as to cover the semiconductor element 3 and contact one surface 6a of the insulating layer 6.
Abstract:
The present invention relates to a method of providing thermal vias in a printed circuit board that includes one or more layers of board material, for conducting heat from components mounted on and/or in the board through said board through said board and away therefrom, and also relates to a printed cirucit board that includes vias arranged in accordance with method. One or more holes (4) are provided in a printed circuit board that includes several metal layers. A metal ball (6) is inserted into each hole and subjected to pressure such as to deform said ball, and tightly fixating the resultant slug against the wall (5) of said hole. The deformed ball or slug fixed in the hole, which may have a metallised inner surface, functions to conduct heat and/or electricity between a metallised topside (2) and bottom side (3) of the printed circuit board and also between intermediate metallised layers in the case of a multi-layer board.
Abstract:
A liquid thermosetting resin composition comprising (A) an epoxy resin, (B) a curing catalyst, and (C) a filler, which is characterized by exhibiting a viscosity of 1500 dPa s or below at 25 DEG C, a gel time of 300 s or above at a temperature at which the composition exhibits a melt viscosity of 10 dPa s or below, and a gel time of 600 s or below at 130 DEG C. In producing a printed wiring board by forming an interlayer dielectric layer of a resin and a conductive circuit on the surface of a wiring substrate having a conductive circuit pattern including holes, the holes are plugged by filling the holes with the above composition, precuring the resulting composition by heating, abrading and removing the protrusions of the composition from the surface, and curing the remaining composition completely by additional heating. Thus, the via holes or through holes of a printed wiring board can be plugged with good workability.
Abstract:
The method for producing an electrical connecting element is essentially characterized in that a plastic deformable substrate is formed with an embossing tool in an embossing step in such a way that recesses are made in said substrate in the areas in which conductive strips and, for instance, through holes or contact surfaces should be formed. The substrate is then coated with a thin conductive layer. In a following step, conductive material is galvanically deposited on the substrate until the recesses are filled with conductive material. Subsequently, the conductive material is removed by means of a removal or etching process until the corresponding areas of the substrate that should not have any conductive surface are free from any metal coating.
Abstract:
A method of manufacturing a low-cost circuit board having a structure capable of preventing defective connections due to thermal stresses appearing in thermal bonding when a circuit board is connected with another through their corresponding terminals. The circuit board includes connection electrodes formed on it to make external connections. Each of the connection electrodes has a portion raised more than 10 mu m above the upper level of wiring conductors, and the raised portion is used for external connections.
Abstract:
A circuit board including IC connection electrodes and electrodes for connection with a mother substrate formed by disposing a conductor pattern on an insulating substrate, and capable of simplifying a production process without a bonding process between the film-like insulating substrate and the conductor pattern. In the circuit board (13) of this invention, a copper foil conductor circuit (5) is formed between polyimide layers (2, 6). Bumps (8) for IC connection and bumps (9) for connecting a mother substrate are disposed on the conductor circuit (5). The polyimide layers (2, 6) are formed by heating polyamide acid layers (2a, 6a) as the precursor of the polyimide at around 350 DEG C to terminate the imidation reaction.