A method of forming circuit lines on a substrate by applying a roughened conductive metal layer using a copper foil carrier. The copper foil is etched away, leaving the roughened conductive metal embedded in the surface of the substrate. The conductive metal may be treated to remove an oxide layer. A photoresist may also be applied over the treated conductive metal layer to define a fine line circuit pattern. The photoresist defining the fine line circuit pattern is then removed to expose trenches in accordance with the desired circuit pattern. Copper is applied into the trenches over the exposed conductive metal, and the remaining photoresist, and conductive metal underlying the remaining photoresist, is removed to finish the fine line circuit pattern.
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a continuation-in-part of U.S. application Ser. No. 08/846,380, filed Apr. 30, 1997, now abandoned, which claims the benefit of U.S. Provisional Application No. 60/016,665, filed on May 1, 1996.
A process for forming printed circuit boards having integral inductor cores. According to the invention, a thin nickel layer is formed on a copper foil. The copper foil structure is then laminated to a substrate such that the nickel layer is in contact with the substrate. The copper foil is removed, leaving the nickel layer on the substrate. Using photomechanical imaging and etching techniques known in the art, NiFe is plated and patterned directly on the nickel layer, thereby forming integral inductor cores of the substrate. This process of the present invention allows for the elimination of several steps used in known processes, while also reducing etch time and minimizing waste of NiFe.
A multi-layer printed wiring board having via holes is characterized by having the outer copper wifing circuit lines on a layer of an alkaline refractory metal which is adjacent to a thermosetting resin layer. An alkaline refractory metal which is insoluble is alkaline etching solutions, is electrodeposited on the surface of copper foil, then a thermosetting resin is applied to the surface and semi-cured to obtain a coated copper foil. The coated copper foil is bonded to one or both faces of an inner layer board having wirings on one or both of its faces. Then, the copper foil on a surface of this laminate is removed by alkaline etching, while selectively leaving the alkaline refractor metal layer. A laser beam is used to form via holes in both the alkaline refractory metal layer and the thermosetting resin layer simultaneously. Via holes of the multi-layered printed wiring board can be easily formed using a laser, and adhesion between the outer wirings made from the plated copper and the insulating resin is improved.
The invention relates to the manufacture of metal foil electrodes useful in the manufacture of printed circuit boards having passive circuit components such as capacitors, resistors or inductors configured in a planar orientation. A copper foil is coated on each opposite side with a thin layer of nickel, which increases the range of functionality of the foil.
A method of electroplating both sides of a dual-sided circuit board substrate having electrically connected, multi-trace circuit patterns formed on both sides of the substrate, without requiring formation and at least partial removal of electrically conductive tie bars, comprises steps of covering and electrically contacting a first one of the circuit patterns with a first layer of electrically conductive material, applying an electrical potential to the first layer of electrically conductive material to effect electroplating on the second one of the circuit patterns, removing the first layer of electrically conductive material, covering and electrically contacting the second one of the circuit patterns with a second layer of electrically conductive material, applying an electrical potential to the second layer of electrically conductive material to effect electroplating on the first one of the circuit patterns, and removing the second layer of electrically conductive material.
The object is to provide a copper foil excellent in the property of selective etching between a resistor layer and a copper layer required in production of a printed-wiring board, and also excellent in UL heat resistance. For this purpose, a copper foil for printed-wiring board comprising a nodular treatment side on one side, wherein a nickel-zinc alloy layer is formed on the nodular treatment side is used for applications of printed-wiring boards. At the same time, a production method suitable for production of the copper foil is provided.
