Abstract: A method is disclosed in which a blind via in a PCB is filled. The vias are plated with a conductor and then with a fusible metal of lower melting point than the conductor. The plated vias are covered with a photoresist and the fusible metal is removed at locations on the PCB other than where the photoresist is disposed. The photoresist is removed and flux is provided on the PCB before the PCB is heated. The heated fusible metal flows into the via.

Abstract: Closed vias are formed in a multilayer printed circuit board by laminating a dielectric layer to one side of a central core having a metal layer on each side. A second dielectric layer is laminated to the other side of the central core. Closed vias in the central core have been formed by drilling partially through but not completely penetrating the central core, and then completing the via from the opposite side with a hole that is much smaller in diameter to form a pathway that penetrates completely through the central core from one side to another. The via is then plated with metal to substantially close the smaller hole. Approximately one half of the closed vias are situated such that the closed aperture faces one dielectric layer and a remainder of the closed vias are situated such that the closed aperture faces the other dielectric layer.

Abstract: A sequentially laminated printed circuit board having highly reliable vias can be fabricated by pattern plating flanges or via lands on a copper foil, laminating the foil to a prepreg so that the flanges are embedded into the surface of the prepreg, creating via holes in the laminate that are substantially concentric with the individual flanges, plating the via holes with copper, chemically or mechanically milling off a portion of the copper plating and optionally some of the copper foil to reduce the overall thickness of the laminate, and laminating a second and optionally a third prepreg to the laminate. The resulting printed circuit board has the flanges embedded in the surface of the laminate so that the inside wall of the flange is electrically and mechanically attached to the outside wall of the plated through hole barrel.

Abstract: Fabricating (100, 1300) a printed circuit board includes fabricating patterned conductive traces (305, 310, 1410, 1415) onto a foil, laminating the patterned conductive traces to a printed circuit board substrate (405, 1505) by pressing on the foil, such that the conductive traces are pressed into a dielectric layer of the printed circuit board, and removing the foil to expose a co-planar surface of conductive trace surfaces and dielectric surfaces. Removal may be done by peeling (125) and/or etching (130, 1315).

Abstract: A method for forming closed vias in a multilayer printed circuit board. A dielectric layer is laminated to one side of a central core having a metal layer on each side. A second dielectric layer is laminated to the other side of the central core. Closed vias in the central core have been formed by drilling partially through but not completely penetrating the central core, and then completing the via from the opposite side with a hole that is much smaller in diameter to form a pathway that penetrates completely through the central core from one side to another. The via is then plated with metal to substantially close the smaller hole. Approximately one half of the closed vias are situated such that the closed aperture faces one dielectric layer and a remainder of the closed vias are situated such that the closed aperture faces the other dielectric layer.

Abstract: A method of making a multilayer, printed wiring board may include pre-drilling a prepreg sheet to form a hole free of glass fibers. The hole has a first diameter. The method includes laminating the pre-drilled prepreg sheet between a copper foil and a substrate and allowing the hole to fill with resin from the prepreg sheet, patterning the copper foil to create an opening in a location associated with the resin-filled hole, drilling a via hole in the resin-filled hole, and metallizing the copper foil and the via hole. The via hole has a second diameter smaller than the first diameter.

Abstract: Closed vias are formed in a multilayer printed circuit board by laminating a dielectric layer to one side of a central core having a metal layer on each side. A second dielectric layer is laminated to the other side of the central core. Closed vias in the central core have been formed by drilling partially through but not completely penetrating the central core, and then completing the via from the opposite side with a hole that is much smaller in diameter to form a pathway that penetrates completely through the central core from one side to another. The via is then plated with metal to substantially close the smaller hole. Approximately one half of the closed vias are situated such that the closed aperture faces one dielectric layer and a remainder of the closed vias are situated such that the closed aperture faces the other dielectric layer.

Abstract: A method for forming closed vias in a multilayer printed circuit board. A dielectric layer is laminated to one side of a central core having a metal layer on each side. A second dielectric layer is laminated to the other side of the central core. Closed vias in the central core have been formed by drilling partially through but not completely penetrating the central core, and then completing the via from the opposite side with a hole that is much smaller in diameter to form a pathway that penetrates completely through the central core from one side to another. The via is then plated with metal to substantially close the smaller hole. Approximately one half of the closed vias are situated such that the closed aperture faces one dielectric layer and a remainder of the closed vias are situated such that the closed aperture faces the other dielectric layer.

Abstract: Fabricating (100, 1300) a printed circuit board includes fabricating patterned conductive traces (305, 310, 1410, 1415) onto a foil, laminating the patterned conductive traces to a printed circuit board substrate (405, 1505) by pressing on the foil, such that the conductive traces are pressed into a dielectric layer of the printed circuit board, and removing the foil to expose a co-planar surface of conductive trace surfaces and dielectric surfaces. Removal may be done by peeling (125) and/or etching (130, 1315).

Abstract: A method is for fabricating an embedded capacitance printed circuit board assembly (400, 1100). The embedded capacitance printed circuit board assembly includes two embedded capacitance structures (110). Each capacitance structure (110) includes a crystallized dielectric oxide layer (115) sandwiched between an outer electrode layer (120) and an inner electrode layer (125) in which the two inner electrode layers are electrically connected together. A rivet via (1315) and a stacked via (1110) formed from a button via (910) and a stacked blind via (1111) may be used to electrically connect the two inner electrode layers together. A spindle via (525) may be formed through the inner and outer layers. The multi-layer printed circuit board may be formed from a capacitive laminate (100) that includes two capacitance structures.

Abstract: A sequentially laminated printed circuit board having highly reliable vias can be fabricated by pattern plating flanges or via lands on a copper foil, laminating the foil to a prepreg so that the flanges are embedded into the surface of the prepreg, creating via holes in the laminate that are substantially concentric with the individual flanges, plating the via holes with copper, chemically or mechanically milling off a portion of the copper plating and optionally some of the copper foil to reduce the overall thickness of the laminate, and laminating a second and optionally a third prepreg to the laminate. The resulting printed circuit board has the flanges embedded in the surface of the laminate so that the inside wall of the flange is electrically and mechanically attached to the outside wall of the plated through hole barrel.

Abstract: A method is for fabricating an embedded capacitance printed circuit board assembly (400, 1100). The embedded capacitance printed circuit board assembly includes two embedded capacitance structures (110). Each capacitance structure (110) includes a crystallized dielectric oxide layer (115) sandwiched between an outer electrode layer (120) and an inner electrode layer (125) in which the two inner electrode layers are electrically connected together. A rivet via (1315) and a stacked via (1110) formed from a button via (910) and a stacked blind via (1111) may be used to electrically connect the two inner electrode layers together. A spindle via (525) may be formed through the inner and outer layers. The multi-layer printed circuit board may be formed from a capacitive laminate (100) that includes two capacitance structures.

Abstract: A method is disclosed for fabricating a patterned embedded capacitance layer. The method includes fabricating (1305, 1310) a ceramic oxide layer (510) overlying a conductive metal layer (515) overlying a printed circuit substrate (505), perforating (1320) the ceramic oxide layer within a region (705), and removing (1325) the ceramic oxide layer and the conductive metal layer in the region by chemical etching of the conductive metal layer. The ceramic oxide layer may be less than 1 micron thick.

Abstract: A method is disclosed for fabricating a patterned embedded capacitance layer. The method includes fabricating (1305, 1310) a ceramic oxide layer (510) overlying a conductive metal layer (515) overlying a printed circuit substrate (505), perforating (1320) the ceramic oxide layer within a region (705), and removing (1325) the ceramic oxide layer and the conductive metal layer in the region by chemical etching of the conductive metal layer. The ceramic oxide layer may be less than 1 micron thick.