Abstract:
This invention is a zincating process of aluminum surfaces for subsequent plating in which the aluminum surfaces are cleaned, contacted with an acidic etching solution comprising a peroxygen compound, the acidic etching solution being substantially free of corrosive nitrate compounds, and contacting the aluminum surfaces with a zincate solution containing 6-60 g/l zinc and 100-500 g/l hydroxide ion. The acidic etching solution is substantially free of toxic inorganic fluoride compounds in order to simplify waste treatment. This invention may be understood with reference to FIG. 2, in particular Step 6.
Abstract:
A circuit board or each circuit board of a multi-layer circuit board includes an electrically conductive sheet coated with an insulating top layer covering one surface of the conductive sheet, an insulating bottom layer covering another surface of the conductive sheet and an insulating edge layer covering an edge of the conductive sheet. An insulating interlayer can be sandwiched between a pair of adjacent circuit boards of a multi-layer circuit board assembly. A landless through-hole or via can extend through one or more of the circuit boards for connecting electrical conductors on opposing surfaces thereof.
Abstract:
A multilayer circuit board for mounting a semiconductor element thereon, comprising a core substrate of a metal material and a plurality of wiring layers stacked on either side of the core substrate, each of the stacked wiring layers being isolated from an adjacent wiring layer by an insulating layer interposed therebetween, the multilayer circuit board having an area at which a heat spreader for dissipating heat generated from the semiconductor element mounted on the circuit board is to be joined to the multilayer circuit board, wherein the multilayer circuit board allows the heat spreader to be joined to the core substrate without the insulating layers being interposed therebetween. A semiconductor device using the multilayer circuit board is also disclosed.
Abstract:
An electrical circuit apparatus (300) that includes: a substrate (330) having a ground layer (336), at least one device aperture (332), and at least one solder aperture (334); a heat sink (310); and an adhesive layer (320) for mechanically coupling the heat sink to the ground layer of the substrate such that at least a portion of the substrate device aperture overlaps the heat sink, the adhesive layer having at least one device aperture and at least one solder aperture, wherein aligning the at least one substrate solder aperture with the at least one adhesive layer solder aperture and aligning the at least one substrate device aperture with the at least one adhesive layer device aperture enables solder wetting in a predetermined area between the heat sink and the ground layer of the substrate.
Abstract:
A circuit board layer 2 in accordance with the present invention includes a conductive sheet 4 sandwiched between an insulating top layer 10 and an insulating bottom layer 14. The top and bottom layers 10 and 14 and the conductive sheet 4 define the circuit board layer 2 having an edge that includes an edge 20 of the conductive sheet 4. An insulating edge layer 18 covers substantially all of the edge 20 of the conductive sheet 4.
Abstract:
A method of making a multi-layered interconnect structure. First and second electrically conductive members are formed on the first and second dielectric layers, respectively. The dielectric layer are formed on opposing surfaces of a thermally conductive layer. A first and second electrically conductive layer is formed within the first dielectric layer. The second electrically conductive layer includes shielded signal conductors and is positioned between the first electrically conductive layer and the thermally conductive layer. A plated through hole (PTH) formed through the interconnect structure is electrically connected to one of the first and second electrically conductive members and to one of the shielded signal conductors. A third dielectric layer, formed on the first dielectric layer and on portions of the first electrically conductive members, substantially overlies the PTH and includes a high density interconnect layer for providing an electrical path from an electronic device to the shielded signal conductors.
Abstract:
A printed circuit board assembly employing a solder vent hole adjacent solder filled interconnect vias connecting to a conductive pallet, is disclosed. The solder vent hole allows gases to escape from an otherwise sealed cavity during solder reflow, relieving positive pressure and thereby allowing solder to flow into it. By providing an escape path for trapped air and gases generated during solder paste reflow, the out-gassing pressure and weight of the molten solder is sufficient to allow the solder paste to flow into the cavity.
Abstract:
In an Integrated Lead Suspension system, it is desired that the stainless steel suspension is grounded to a controlled ground potential. This requires creating a grounding path between the stainless steel suspension and a copper trace layer through a layer of dielectric material that separates the stainless steel suspension and the copper layer. The copper trace layer and subsequently the stainless steel suspension can then be grounded to a controlled ground potential. This invention proposes several methods of creating a ground path between the stainless steel suspension and the copper trace layer.
Abstract:
A method of forming a printed circuit board or circuit card is provided with a metal layer which serves as a power plane sandwiched between a pair of photoimageable dielectric layers. Photoformed metal filled vias and photoformed plated through holes are in the photopatternable material, and signal circuitry is on the surfaces of each of the dielectric materials and connected to the vias and plated through holes. A border may be around the board or card including a metal layer terminating in from the edge of one of the dielectric layers. A copper foil is provided with clearance holes. First and second layers of photoimageable curable dielectric material is disposed on opposite sides of the copper which are photoimageable material. The patterns are developed on the first and second layers of the photoimageable material to reveal the metal layer through vias. At the clearance holes in the copper, through holes are developed where holes were patterned in both dielectric layers. Thereafter, the surfaces of the photoimageable material, vias and through holes are metalized by copper plating. This is preferably done by protecting the remainder of the circuitry with photoresist and utilizing photolithographic techniques. The photoresist is thereafter removed, leaving a circuit board or card having metalization on both sides, vias extending from both sides to the copper layer in the center, plated through holes connecting the two outer circuitized copper layers.
Abstract:
The density of electronic packaging and the electrical reliability of the sub-assemblies utilizing stacked blind vias are improved by providing a blind, landless via in a first dielectric layer laminated to a conductive metal core serving as a ground plane or a power plane. A hole is provided through the dielectric layer extending to the core. A metal, such as copper, is deposited electrolytically using the metal core as the cathode, or electrolessly without seeding into the hole. The metal is deposited on the core and progressively builds in the hole to the depth required for the via. A second dielectric layer is laminated to the first, and is provided with a second layer blind via aligned with the first via. This second via may be formed by conventional plating techniques. Multiple dielectric layers with stacked blind vias can be assembled in this manner.