A ceramic substrate of the present disclosure is a ceramic substrate including a ceramic body having a ceramic layer on a surface thereof and a surface electrode placed on a primary face of the ceramic body. Between the surface electrode and the ceramic layer is an oxide layer made of an insulating oxide having a melting point higher than the firing temperature for the ceramic layer. The oxide layer also extends on the ceramic layer not occupied by the surface electrode. The oxide layer on the ceramic layer not occupied by the surface electrode has a rough surface.

A ceramic substrate of the present disclosure is a ceramic substrate including a ceramic body having a ceramic layer on a surface thereof and a surface electrode placed on a primary face of the ceramic body. Between the surface electrode and the ceramic layer is an oxide layer made of an insulating oxide having a melting point higher than the firing temperature for the ceramic layer. The oxide layer also extends on the ceramic layer not occupied by the surface electrode. The oxide layer on the ceramic layer not occupied by the surface electrode has a rough surface.

A stretchable circuit board includes plural stretchable bases, and plural stretchable wiring portions, at least one of which is provided on each of main surfaces, facing each other, of the plural stretchable bases, in which the stretchable wiring portions provided on the main surfaces are electrically continuous with each other through a connecting portion.

A stretchable circuit board includes plural stretchable bases, and plural stretchable wiring portions, at least one of which is provided on each of main surfaces, facing each other, of the plural stretchable bases, in which the stretchable wiring portions provided on the main surfaces are electrically continuous with each other through a connecting portion.

A printed wiring board includes a laminate, a wiring layer formed on first main surface of the laminate and including conductor pads, via conductors including first and second via conductors and formed in the laminate such that each via conductor has diameter gradually reducing from the first main surface toward second main surface of the laminate, and conductor post formed on the first via conductors such that each conductor post includes a metal foil and a plating layer formed on the metal foil. The via conductors are formed such that the first via conductors are positioned in an outer edge portion of the laminate and have minimum-diameter-side surfaces positioned to form a same plane with the second main surface of the laminate and that the second via conductors are positioned in a central portion of the laminate and have minimum-diameter-side surfaces recessed from the second main surface of the laminate.

Provided is an interlayer insulating film for a multi-layered printed wiring board, including a wiring embedding layer (A) obtained by forming a thermosetting resin composition (I) into a layer, and an adhesion assisting layer (B) obtained by forming a thermosetting resin composition (II) into a layer, in which the interlayer insulating film contains a residual solvent in an amount of 1% to 10% by mass in a total amount of the wiring embedding layer (A) and the adhesion assisting layer (B), and the residual solvent contains an organic solvent having a boiling point of 150° C. to 230° C. in an amount of 10% by mass or more in a total amount of the residual solvent.

A power module substrate 10 is provided with: an insulating substrate 1; and a metal sheet 2 that is joined to the insulating substrate 1 via a brazing material 3, wherein regarding the surface roughness, in the thickness direction, of the lateral surface of the metal sheet 2, the surface roughness of a corner 2a farthest from the center of the metal sheet 2 is larger than the surface roughness of plane parts 2b, which bound the corner, in at least a plan view. Also provided is a power module 100 which is formed by mounting an electronic component 40 on this power module substrate 10.

The present invention provides a process for preparing a pre-treated low Dk-type glass fabric for constituting a circuit board, comprising pre-treating low Dk-type glass fabric with a pre-treating varnish having a Dk close to the Dk of the used low Dk-type glass fabric at different temperatures and having a small Df. The present invention further provides a bonding sheet and a circuit board prepared thereby. The circuit boards prepared by the preparation process of the present invention have a Dk having small differences in warp and weft directions, and can effectively solve the problem of signal propagation delay. The circuit boards have a small Df, so as to have a small signal loss. Meanwhile, the cured, partially-cured or uncured dry glue obtained after drying the solvent of the pre-treating varnish has similar dielectric properties at different temperatures to the used low Dk-type glass fabric, so that the circuit boards have a very small signal propagation delay at different temperatures.

A flexible substrate, a method of processing a flexible substrate and a system of processing a flexible substrate. The method of processing the flexible substrate includes: measuring a first expansion volume of the flexible substrate; and applying a first application pressure to the flexible substrate to laminate the flexible substrate on a base substrate; according to a first corresponding relationship between a first pressure applied to the flexible substrate and a compressive expansion volume generated by the flexible substrate in compression and according to the first expansion volume, the first application pressure is selected to allow a second expansion volume of the flexible substrate to at least partially compensate for the first expansion volume.

The present invention provides a surface treatment liquid for metal having a sufficiently high film-forming property. The present invention relates to a surface treatment liquid for metal comprising an azole silane coupling agent, the surface treatment liquid further comprises (A) an organic acid ion having one to three acidic groups in one molecule; (B) an inorganic acid (or mineral acid) ion; (C) an alkali metal ion and/or an ammonium ion; and (D) a copper ion.