A multilayer resin substrate includes a stacked body including resin layers stacked on each other, a first planar conductor on a resin layer, and an interlayer connection conductor on a resin layer. The interlayer connection conductor includes a first interlayer connection conductor connected to an external conductor, and a second interlayer connection conductor bonded to the first interlayer connection conductor and a planar conductor. The first and second interlayer connection conductors are made of different materials. The second interlayer connection conductor includes a constricted portion including a smaller planar cross-sectional area than a different portion, between a bonding portion to which the first interlayer connection conductor is bonded and a bonding portion to which the planar conductor is bonded.

A method for producing a resin multilayer board includes preparing a first resin layer including one or more conductor patterns that are disposed thereon and a conductor pattern including a first region that is to be connected to a conductor via; forming a paint layer by applying a paste including a LCP powder to a second region entirely covering the one or more conductor patterns; forming a cavity in the paint layer such that at least the first region is exposed, by performing laser processing; stacking a second resin layer including the conductor via on the first resin layer; and obtaining a resin multilayer board including a layer obtained by curing the paint layer, by applying pressure and heat to the multilayer body to perform thermal pressure-bonding.

A thin circuit board (100) and a method of manufacturing the same, the thin circuit board (100) includes: a dielectric layer (40); an inner circuit substrate (30); and a metal layer (50) formed on at least one side of the inner circuit substrate (30). The metal layer (450) is covered by the dielectric layer (40). The dielectric layer (40) includes an outermost insulating layer (11) and a bonding structure (20) sandwiched between the inner circuit substrate (30) and the metal layer (50), the metal layer (50) is wrapped by the insulating layer (11) and the bonding structure (20).

The method for producing a printed wiring board according to the present invention with use of a metal-clad laminated sheet including a metal foil laminated on each of both surfaces of an insulating resin base material, the method at least including: a step (1) of irradiating a predetermined position in a surface (A) of the metal-clad laminated sheet with a laser to provide a via hole leading to the metal foil in a surface opposite to the surface (A); and a step (2) of irradiating a predetermined position in a surface (B), located in the opposite side to the surface (A), of the metal-clad laminated sheet with a laser to provide a via hole leading to the metal foil in a surface opposite to the surface (B).

A process of manufacturing a multilayer sheet having electrically conductive patterns comprises feeding a first polymer layer and a second polymer composition to a calendering stack, the first polymer layer having an inner electrically conductive pattern disposed thereon, the first polymer layer comprising a first polymer composition, which contains a first polymer having a first glass transition temperature, and the second polymer composition comprising a second polymer and a laser direct structure additive (LDS), the second polymer having a second glass transition temperature that is 50 to 100° C. lower than the first glass transition temperature; pressing the first polymer layer and the second polymer composition together to laminate a second polymer layer which comprises the second polymer composition to the first polymer layer, the second polymer layer having an inner surface facing the inner electrically conductive pattern of the first polymer layer and an opposing outer surface; forming an activated surface pattern on the outer surface of the second polymer layer; and applying a conductive metal on the activated surface pattern, wherein the first polymer layer is in direct physical contact with the second polymer layer.

A multilayer substrate includes at least three coil conductors respectively patterned on different surfaces of a first main surface of a laminated body, a second main surface of the laminated body, and laminated interfaces of insulating base materials and that are arranged in a lamination direction. The at least three coil conductors include first and second coil conductors, and are connected in series between first and second external electrodes. A surface at which another coil conductor is provided is not interposed between two surfaces at which the first and second coil conductors are provided, respectively. Further, the first and second coil conductors are directly connected to the first and second external electrodes, respectively, without another coil conductor interposed therebetween.

A resin multilayer substrate includes a stacked body provided by stacking and thermocompression bonding resin layers, a first conductor pattern inside the stacked body, and a first protective coating covering at least a first surface and a side surface of the first conductor pattern. The resin layers are made of a first thermoplastic resin, and the first protective coating is made of a second thermoplastic resin. Both of the first and second thermoplastic resins soften at a predetermined press temperature or less. The second thermoplastic resin has a storage modulus lower than a storage modulus of the first thermoplastic resin at a temperature equal to or less than the predetermined press temperature and equal to or more than room temperature.

A laminate structure that includes: a resin film containing a thermoplastic resin and having a plurality of voids; and a conductor layer adjacent to a main surface of the resin film, wherein a first set of voids of the plurality of voids are localized between a first position proximal to an end surface of the resin film facing the conductor layer and a second position distant from the first position by one-third of the thickness of the resin film in a lamination direction of the resin film and the conductor layer such that the first set of voids between the first position and the second position are greater in number than a second set of voids between the second position and a third position distant from the second position by one-third of the thickness of the resin film in a direction away from the first position in the lamination direction.

A multilayer substrate includes insulating base materials stacked in a stacking direction, at least one conductor pattern on at least one of the insulating base materials, the at least one conductor pattern including two opposite major surfaces, and insulating protective films on both of the two opposite major surfaces of the at least one conductor pattern.

A manufacturing method of a mounting structure, the method including a step of preparing a mounting member including a first circuit member and a plurality of second circuit members placed on the first circuit member; a disposing step of disposing a thermosetting sheet and a thermoplastic sheet on the mounting member, with the thermosetting sheet interposed between the thermoplastic sheet and the first circuit member; a first sealing step of pressing a stack of the thermosetting sheet and the thermoplastic sheet against the first circuit member, and heating the stack, to seal the second circuit members and to cure the thermosetting sheet into a first cured layer; a removal step of removing the thermoplastic sheet from the first cured layer; and a coating film formation step of forming a coating film on the first cured layer, after the removal step. At least one of the second circuit members is a hollow member having a space from the first circuit member, and in the first sealing step, the second circuit members are sealed so as to maintain the space.