International Business Machines Corporation

Kristen Ann Stauffer

Thomas R Miller

Michael Wozniak

Christina Marie Boyko

Richard Allen Day

Kevin Taylor Knadle

Robert Jeffrey Day

Anilkumar Chinuprasad Bhatt

Michael James Cummings

A printed wiring board is formed from two or more layers, one of which has circuit lines formed thereon, and wherein the surfaces of the circuit lines are roughened only in areas that require good copper to laminate adhesion. The remainder of the circuit line surfaces are smooth. Thus, those areas for propagation of the signal on signal lines have the circuit lines smooth to maximize the signal propagation effect, while those areas where the signal propagation is not critical are rough, which improves the adhesion of one layer to another. On the voltage planes, the surface in those regions opposite the smooth surfaces of the signal planes is smooth. Thus, these areas of the voltage planes can be maintained smooth while the other areas of the surface of the voltage planes can be roughened, providing good adhesion to the adjoining dielectric material.

Selectively roughening conductors for high frequency printed wiring boards

The present invention teaches a simplified process for fabricating high density printed wiring boards using a semi-additive process. Steps required to achieve this objective include adhering an electroless plated copper commoning layer to a surface roughened dielectric substrate. Subsequently, the commoning layer is photolithographically personalized by covering the commoning layer with a resist and then uncovering predetermined areas of the aforementioned commoning layer. Consequently, the semi-additive method involves electroplating copper onto the uncovered areas of the commoning layer, thereby generating copper features and circuitry. Finally, the semi-additive process requires the stripping of the remaining photoresist, and the unplated electroless copper layer is etched in order to electronically isolate the copper features and circuitry lines.

Process for manufacturing a printed wiring board

A method of forming an electronic structure, including adhesively coupling a plated metallic layer (e.g. a copper layer) of a plated through hole (PTH) to holefill material (e.g., epoxy resin) distributed within the PTH. The adhesive coupling utilizes an adhesion promoter film on the plated metallic layer such that the adhesion promoter film is bonded to the resin. The adhesion promoter film may include a metallic oxide layer such as a layer containing cupric oxide and cuprous oxide, which could be formed from bathing a PTH plated with copper in a solution of sodium chlorite. The adhesion promoter film may alternatively include an organometallic layer such as a layer that includes a chemical complex of metal and an organic corrosion inhibitor. The organometallic layer could be formed from bathing the PTH in a bath of hydrogen peroxide, sulfuric acid, and the organic corrosion inhibitor.

Protection of a plated through hole from chemical attack

A method of making a circuitized substrate which may be utilized as a chip carrier structure. The method involves the steps of providing a dielectric member and routing out a preselected portion of the base member to form an aperture. Metallization of the dielectric member and the walls of the aperture then occurs, followed by circuitization of the surfaces of the dielectric member. Direct metallization of the aperture walls eliminates many manufacturing steps previously required to metallize the aperture walls.

Method of making a circuitized substrate with an aperture

The present invention teaches a simplified process for fabricating high density printed wiring boards using a semi-additive process. A roughened copper foil is laminated to a dielectric substrate. The foil is subsequently removed from the dielectric to create a roughened, irregular surface on the dielectric substrate. Vertical angle through holes and blind holes are formed in the substrate. A uniform copper commoning layer is electrolessly plated to the roughened dielectric substrate and through holes. A photoresist is applied on the surface of the electroless plated layer and irradiated through a mask having printed circuit features. After developing the photoresist the uncovered electroless layer is electrolytically plated to create the final features and circuitry. After stripping the remaining photoresist the unplated electroless copper layer is etched to electronically isolate the copper features and circuitry lines.

An electronic structure, and associated method of formation, in which a plated metallic layer such as a copper layer, of a plated through hole (PTH) is adhesively coupled to holefill material distributed within the PTH. The holefill material includes a resin such as an epoxy and optionally includes a particulate component such as a copper powder. The adhesive coupling is accomplished by forming an adhesion promoter film on the plated metallic layer such that the adhesion promoter film is bonded to the resin. The adhesion promoter film may include a metallic oxide layer such as layer containing cupric oxide and cuprous oxide, which could be formed from bathing the PTH in a solution of sodium chlorite. Application of a reducing solution of dimethylamine borane to the cuprous oxide layer would convert some of the cuprous oxide to cupric oxide in the metallic oxide layer. Another possibility for an adhesion promoter film is an organometallic layer such as a layer that includes a chemical complex of metal and an organic corrosion inhibitor. Useful organic corrosion inhibitors for this purpose include triazoles, tetrazoles, and imidazoles. The organometallic layer could be formed from bathing the PTH in a bath of hydrogen peroxide, sulfuric acid, and an organic corrosion inhibitor.

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Vestal, NY, United States of America

Kristen Ann Stauffer