In some embodiments, methods include drilling one or a plurality of PTHs with any industrial grade drill to fabricate holes with positive etch back, flooding the PTHs with a dilute solution of an acrylate monomer/oligomer containing an appropriate level of peroxide initiator, polymerizing the acrylate, and then rising the PTHs with the solvent used in the formulation of the acrylate material. In one embodiment, the printed circuit board may include a substrate comprising a plurality of metal layers separated by a plurality of insulating layers; a plurality of plated through holes formed in the substrate, each plated through hole comprising: recesses formed at each insulating layer, copper lands between the recesses, a polymer coating in each recess, and a metal layer lining the plated through hole.

A liquid solder resist composition contains a carboxyl group-containing resin, a photopolymerizable compound containing at least one compound selected from a group consisting of a photopolymerizable monomer and a photopolymerizable prepolymer, a photopolymerization initiator, and a titanium dioxide. The photopolymerization initiator contains a bisacylphosphine oxide-based photopolymerization initiator, a first -hydroxyalkyl phenone-based photopolymerization initiator that is a liquid at 25 C., and a second -hydroxyalkyl phenone-based photopolymerization initiator that is a solid at 25 C.

A liquid solder resist composition contains a carboxyl group-containing resin, a photopolymerizable compound containing at least one compound selected from a group consisting of a photopolymerizable monomer and a photopolymerizable prepolymer, a photopolymerization initiator, and a titanium dioxide. The photopolymerization initiator contains a bisacylphosphine oxide-based photopolymerization initiator, a first -hydroxyalkyl phenone-based photopolymerization initiator that is a liquid at 25 C., and a second -hydroxyalkyl phenone-based photopolymerization initiator that is a solid at 25 C.

A solder resist composition includes: (A) a carboxyl group-containing resin; (B) an epoxy compound; (C) titanium dioxide; (D) a photopolymerization initiator; and (E) an antioxidant. The component (B) contains a hydroquinone epoxy compound represented by following formula (1). The component (D) contains (D1) a bisacylphosphine oxide-based photopolymerization initiator and (D2) an -hydroxy alkylphenone-based photopolymerization initiator.

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An interconnection substrate includes a plurality of electrically conductive elements of at least one wiring layer defining first and second lateral directions. Electrically conductive projections for bonding to electrically conductive contacts of at least one component external to the substrate, extend from the conductive elements above the at least one wiring layer. The conductive projections have end portions remote from the conductive elements and neck portions between the conductive elements and the end portions. The end portions have lower surfaces extending outwardly from the neck portions in at least one of the lateral directions. The substrate further includes a dielectric layer overlying the conductive elements and extending upwardly along the neck portions at least to the lower surfaces. At least portions of the dielectric layer between the conductive projections are recessed below a height of the lower surfaces.

Methods to mask an RF switch prior to a coating process and RF switches that have been masked according to these methods.

This photosensitive resin composition includes: (A) a photopolymerizable compound including at least one of a photopolymerizable monomer and a photopolymerizable oligomer; (B) titanium dioxide; and (C) a photopolymerization initiator. The component (C) includes (C1) an acylphosphine oxide-containing photopolymerization initiator and (C2) a phenylglyoxylic acid-containing photopolymerization initiator.

A member 1 for forming wiring includes an adhesive layer 10 and a metal layer 20. The adhesive layer 10 is composed of an adhesive composition containing conductive particles 12 and a thermosetting component. The metal layer 20 is disposed on the adhesive layer 10. In such a member 1 for forming wiring, the adhesive layer contains an epoxy resin and a phenolic resin, as the thermosetting component.

Systems, apparatus, articles of manufacture, and methods to reduce discoloration of solder resists in immersion cooling environments are disclosed. An example apparatus includes a substrate. The example apparatus further includes a solder resist layer on an exterior surface of the substrate. The solder resist layer does not include a transition metal.

A printed circuit board may include a substrate body portion, conductive patterns on a top surface of the substrate body portion, and a photosensitive insulating layer on the top surface of the substrate body portion and including an opening exposing at least one of the conductive patterns. The photosensitive insulating layer includes first to third sub-layers stacked sequentially. The first sub-layer includes an amine compound or an amide compound. A refractive index of the second sub-layer is lower than a refractive index of the third sub-layer. A photosensitizer content of the second sub-layer is higher than a photosensitizer content of the third sub-layer.