An apparatus for encapsulating at least one electronic component disposed on a printed circuit board may include a liquid-tight enclosure that surrounds the electronic component and that is fixed with respect to the electronic component and the circuit board, and an encapsulating material disposed inside the enclosure and encapsulating the electronic component. The enclosure may include at least one sidewall and a top. The at least one sidewall may include a rigid material, a lower edge that is proximal to the printed circuit board, an upper edge that is distal from the circuit board, and a height above the circuit board that is no more than 0.003 inches greater than a height of the electronic component above the circuit board. The top may include a solid surface disposed on the upper edge of the at least one sidewall, where the at least one sidewall and the top form the enclosure.

A film for a metal layer laminate board and a metal layer laminate board have excellent stiffness, while capable of suppressing fluctuation of a dielectric constant before and after pressing. The film for a metal layer laminate board includes a porous resin layer having a tensile elastic modulus at 25° C. of 800 MPa or more and 2000 MPa or less.

To provide a glass resin laminate of the present invention, in which the glass substrate and the resin layer containing a TFE polymer are strongly laminated, is hardly warped and is excellent in the electrical properties, a composite laminate further having a metal foil, and methods for producing them. A glass resin laminate comprising a glass substrate 10 having an uneven surface 12 with an arithmetic mean roughness of at least 5 nm, and a resin layer containing a tetrafluoroethylene polymer in contact with the uneven surface 12, wherein the uneven surface 12 has specific convex portions 21 and 22 which narrow at at least a part of the root portion as compared with the tip portion.

A resin composition for a PCB includes a styrene-butadiene-styrene block copolymer in an amount from 95 to 100 parts by weight, a modified porous spheres of silicon oxide in an amount from 1 to 50 parts by weight, and a liquid polybutadiene in an amount from 5 to 50 parts by weight. The styrene-butadiene-styrene block copolymer and the liquid polybutadiene both include vinyl groups on the molecular side chains. The modified porous spheres of silicon oxide also include vinyl groups. An adhesive film and a circuit board using the resin composition are also provided.

There is provided a metal-clad laminate in which the transmission loss of electrical signals can be reduced, a finer pitch of a circuit pattern is possible, a high precision and fine circuit can be formed, and the close adhesiveness of the metal film is excellent. The metal-clad laminate includes a coating film and a metal film laminated on a base material film in this order, wherein the metal film is a metal film formed by at least any formation method of plating, sputtering, and vapor deposition, and a surface roughness (Rz) of the coating film is 1 μm or less.

A heat curable resin composition which allows voids to be removed by heating and vacuum operation after reflow soldering, and a circuit board with an electronic component mounted thereon are provided. The heat curable resin composition of the present embodiment includes a liquid epoxy resin, a hemiacetal ester derived from monocarboxylic acid and polyvinyl ether, a curing agent, and a filler.

A resin film containing a fluororesin as a main component has, on at least one surface thereof, a pre-treated surface having a content ratio of oxygen atoms or nitrogen atoms of 0.2 atomic percent or more. A coverlay includes the resin film and an adhesive layer laminated on the pre-treated surface. A substrate for a printed wiring board includes the resin film and a conductive layer laminated on the pre-treated surface. A printed wiring board includes an insulating base layer, a conductive pattern laminated on at least one surface of the base layer, and the coverlay for a printed wiring board, the coverlay being laminated on the conductive pattern.

A circuit board includes an insulating made by a low dielectric resin composition includes a low dielectric resin containing acid anhydride, an epoxy resin, polyphenylene ether resin with vinyl and active esters, maleic acid liquid polybutadiene, and an accelerator. Such low dielectric resin can be dissolved in organic solvent more easily than a low dielectric resin without acid anhydride, and the low dielectric resin containing acid anhydride has a better compatibility with other organic components than a low dielectric resin without acid anhydride. A low dielectric resin composition with lower dielectric constant and better properties can thus be obtained.

An adhesive composition, which exhibits excellent adhesion to base films made from polyimide resins and the like or copper foils, as well as superior electrical properties, and a laminate having an adhesive layer, which is low in warpage when the adhesive layer is in the B stage, and which is excellent in storage stability of the laminate, are provided. The adhesive composition includes a modified polyolefin-based resin and an epoxy resin, in which the modified polyolefin-based resin is a resin resulting from graft-modification of an unmodified olefin resin with a modifying agent containing an α,β-unsaturated carboxylic acid or derivative thereof, wherein the content of the modified polyolefin-based resin is 50 parts by mass or more relative to 100 parts by mass of the solid content of the adhesive composition; the content of the epoxy resin is from 1 to 20 parts by mass relative to 100 parts by mass of the modified polyolefin-based resin; and the dielectric constant of a cured body of the adhesive is less than 2.5 as measured at a frequency of 1 GHz.

An electrical circuit board includes a first conductive layer and a second conductive layer. And an interlayer forming a thermal barrier is placed between the first conductive layer and the second conductive layer, wherein the thermal barrier reduces heat transfer between the first conductive layer and the second conductive layer.