The invention discloses a circuit board enhancing structure and a manufacture method thereof. The method includes the following steps: providing a substrate; forming a first circuit on the substrate; forming a first dielectric layer enclosing the first circuit on the substrate; forming a first opening on the first dielectric layer; forming a first pattern photoresist layer on the first dielectric layer to divide a surface of the first dielectric layer as a first structure enhancing area and a second circuit area, wherein the first opening is disposed in the first structure enhancing area; forming a second circuit in the second circuit area and a first enhancing structure in the first opening, wherein the first enhancing structure protrudes from the first opening; removing the first pattern photoresist layer; and forming a second dielectric layer enclosing the second circuit and the first enhancing structure on the first dielectric layer.

A high-frequency electronic component includes a ceramic multilayer substrate, ground electrodes provided at different layers of the ceramic multilayer substrate, and a shielding film covering at least a side surface among surfaces of the ceramic multilayer substrate. Two or more of the ground electrodes are exposed to the side surface of the ceramic multilayer substrate but do not protrude from this side surface, and are electrically connected to the shielding film. On the side surface of the ceramic multilayer substrate, the two or more of the ground electrodes at least partially overlap each other in a thickness direction of the ceramic multilayer substrate, with a distance in the thickness direction between the overlapping ground electrodes being 5 μm or greater.

A high-frequency electronic component includes a ceramic multilayer substrate, ground electrodes provided at different layers of the ceramic multilayer substrate, and a shielding film covering at least a side surface among surfaces of the ceramic multilayer substrate. Two or more of the ground electrodes are exposed to the side surface of the ceramic multilayer substrate but do not protrude from this side surface, and are electrically connected to the shielding film. On the side surface of the ceramic multilayer substrate, the two or more of the ground electrodes at least partially overlap each other in a thickness direction of the ceramic multilayer substrate, with a distance in the thickness direction between the overlapping ground electrodes being 5 μm or greater.

A high-frequency electronic component includes a ceramic multilayer substrate, ground electrodes provided at different layers of the ceramic multilayer substrate, and a shielding film covering at least a side surface among surfaces of the ceramic multilayer substrate. Two or more of the ground electrodes are exposed to the side surface of the ceramic multilayer substrate and are electrically connected to the shielding film. On the side surface of the ceramic multilayer substrate, the two or more of the ground electrodes do not overlap each other in a thickness direction of the ceramic multilayer substrate.

A circuit board structure includes a circuit substrate, a first circuit layer, and a second circuit layer. The circuit substrate has a surface and includes at least one conductive structure and at least one patterned circuit layer. The conductive structure is electrically connected to the patterned circuit layer, and an upper surface of the conductive structure is aligned with the surface. The first circuit layer is directly disposed on the surface of the circuit substrate and electrically connected to the conductive structure. A line width of the first circuit layer is less than or equal to ¼ of a line width of the patterned circuit layer. The second circuit layer is directly disposed on the first circuit layer and electrically connected to the first circuit layer.

The insertion loss of a multilayer substrate and an antenna element is reduced. A multilayer substrate according to an embodiment of the present disclosure includes a multilayer body, a wire conductor, and a first ground electrode. The multilayer body is formed by dielectric layers being layered. The wire conductor is formed in the multilayer body, and a radio frequency signal passes through the wire conductor. The first ground electrode is formed in or on the multilayer body and includes a first surface that faces the wire conductor. The first surface includes a first region and a second region. The surface roughness of the first region is lower than the surface roughness of the second region. The first region overlaps at least part of the wire conductor in plan view in a direction normal to the first ground electrode.

The insertion loss of a multilayer substrate and an antenna element is reduced. A multilayer substrate according to an embodiment of the present disclosure includes a multilayer body, a wire conductor, and a first ground electrode. The multilayer body is formed by dielectric layers being layered. The wire conductor is formed in the multilayer body, and a radio frequency signal passes through the wire conductor. The first ground electrode is formed in or on the multilayer body and includes a first surface that faces the wire conductor. The first surface includes a first region and a second region. The surface roughness of the first region is lower than the surface roughness of the second region. The first region overlaps at least part of the wire conductor in plan view in a direction normal to the first ground electrode.

A method for manufacturing a wiring circuit board that is a double-sided wiring circuit board includes a first step of preparing a laminate and a second step. The laminate includes a metal core layer, insulating layer, and conductor layers. The insulating layer has a region and an opening that are adjacent to each other. The insulating layer has a region including a part facing the region in a thickness direction, and an opening adjacent to the region. The conductor layer includes a wiring portion and a conductive portion. The conductor layer includes a wiring portion and a conductive portion. In the second step, the first and second etching treatments for etching the metal core layer through the openings are carried out to form a via portion having a periphery surrounded by a space, extending between the regions, and connected to the conductive portions.

A method for manufacturing a circuit board comprises: a first single-sided board and an insulating structure are provided. The first single-sided board is pressed to the insulating structure and covers opposite side surfaces of the insulating structure to form a first laminated board. A second single-sided board and a third single-sided board are provided. The second single-sided board is pressed to the third single-sided board and covers opposite side walls of the third single-sided board to form a second laminated board. An inner wiring layer is formed by the second laminated board. The second laminated board with the inner wiring layer and the first laminated board are pressed to form an intermediate structure. Outer wiring layers are formed by the intermediate structure. Covering films are formed on surfaces of the outer wiring layers. Electromagnetic interference shielding layers are formed on the covering films.

A circuit board with reduced dielectric losses enabling the movement of high frequency signals includes an inner circuit board and two outer circuit boards. The inner circuit board includes a first conductor layer and a first substrate layer. The first conductor layer includes a signal line and two ground lines on both sides of the signal line. The first substrate layer covers a side of the first conductor layer and defines first through holes which expose the signal line. Each outer circuit board includes a second substrate layer and a second conductor layer. The second substrate layer abuts the inner circuit board and defines second through holes which are not aligned with the first through holes, partially surrounding the signal line with air which has a very low dielectric constant. A method for manufacturing the high-frequency circuit board is also disclosed.