A printed circuit board module comprises: a first printed circuit board; a second printed circuit board arranged on one surface of the first printed circuit board; a third printed circuit board arranged on the other surface of the first printed circuit board; and a core passing through the first printed circuit board to the third printed circuit board, wherein the second printed circuit board includes a first coil, the third printed circuit board includes a second coil, and the cross-sectional area of the second printed circuit board and the third printed circuit board is less than the cross-sectional area of the first printed circuit board.

A printed circuit board module comprises: a first printed circuit board; a second printed circuit board arranged on one surface of the first printed circuit board; a third printed circuit board arranged on the other surface of the first printed circuit board; and a core passing through the first printed circuit board to the third printed circuit board, wherein the second printed circuit board includes a first coil, the third printed circuit board includes a second coil, and the cross-sectional area of the second printed circuit board and the third printed circuit board is less than the cross-sectional area of the first printed circuit board.

Laminate structures and configurations of fiducials for laminates structures for electronic devices are disclosed. Fiducials are formed in laminate structures to provide increased visibility and contrast, thereby improving detection of the fiducials with optical detection equipment of automated machines commonly used in the electronics industry. Fiducials are disclosed that are defined by openings in laminate structures that extend to depths within the laminate structures to provide sufficient contrast. Openings for fiducials may be arranged to extend through multiple metal layers and dielectric layers of the laminate structures. The fiducials may be formed by laser drilling or other subtractive processing techniques. Fiducials as disclosed herein may be coated with additional layers or coatings, such as a metal coating that includes an electromagnetic shield for electronic devices, and the fiducials are configured with sufficient visibility and contrast to remain detectable through the additional layers or coatings.

Laminate structures and configurations of fiducials for laminates structures for electronic devices are disclosed. Fiducials are formed in laminate structures to provide increased visibility and contrast, thereby improving detection of the fiducials with optical detection equipment of automated machines commonly used in the electronics industry. Fiducials are disclosed that are defined by openings in laminate structures that extend to depths within the laminate structures to provide sufficient contrast. Openings for fiducials may be arranged to extend through multiple metal layers and dielectric layers of the laminate structures. The fiducials may be formed by laser drilling or other subtractive processing techniques. Fiducials as disclosed herein may be coated with additional layers or coatings, such as a metal coating that includes an electromagnetic shield for electronic devices, and the fiducials are configured with sufficient visibility and contrast to remain detectable through the additional layers or coatings.

The present disclosure relates to a dielectric substrate that may include a polyimide layer and a first filled polymer layer overlying the polyimide layer. The first filled polymer layer may include a resin matrix component, and a first ceramic filler component. The first ceramic filler component may include a first filler material. The first filler material may further have a mean particle size of at not greater than about 10 microns.

The present disclosure relates to a dielectric substrate that may include a polyimide layer and a first filled polymer layer overlying the polyimide layer. The first filled polymer layer may include a resin matrix component, and a first ceramic filler component. The first ceramic filler component may include a first filler material. The first filler material may further have a mean particle size of at not greater than about 10 microns.

A stress mitigation region is formed in which a predetermined number of stress mitigation holes penetrating through a wiring are disposed is formed in a proximity of a bonding portion of an electronic component via which the electronic component is bonded to the wiring with an electrically conductive bonding agent. Accordingly, even if a stress is generated in the wiring due to a heat, the stress mitigation holes are deformed so that the stress acted upon the electrically conductive bonding agent becomes small and a generation of cracks in the electrically conductive bonding agent can be suppressed. In addition, the stress mitigation holes are made circular so that concentrations of a current and the stress can be reduced and the generation of the cracks in the wiring can be suppressed.

A stress mitigation region is formed in which a predetermined number of stress mitigation holes penetrating through a wiring are disposed is formed in a proximity of a bonding portion of an electronic component via which the electronic component is bonded to the wiring with an electrically conductive bonding agent. Accordingly, even if a stress is generated in the wiring due to a heat, the stress mitigation holes are deformed so that the stress acted upon the electrically conductive bonding agent becomes small and a generation of cracks in the electrically conductive bonding agent can be suppressed. In addition, the stress mitigation holes are made circular so that concentrations of a current and the stress can be reduced and the generation of the cracks in the wiring can be suppressed.

The present invention provides a high thermal conductive silicon nitride sintered body having a thermal conductivity of 50 W/m.Math.K or more and a three-point bending strength of 600 MPa or more, wherein when an arbitrary cross section of the silicon nitride sintered body is subjected to XRD analysis and highest peak intensities detected at diffraction angles of 29.3±0.2°, 29.7±0.2°, 27.0±0.2°, and 36.1±0.2° are expressed as I.sub.29.3°, I.sub.29.7°, I.sub.27.0°, and I.sub.36.1°, a peak ratio (I.sub.29.3°)/(I.sub.27.0°+I.sub.36.1°) satisfies a range of 0.01 to 0.08, and a peak ratio (I.sub.29.7°)/(I.sub.27.0°+I.sub.36.1°) satisfies a range of 0.02 to 0.16. Due to above configuration, there can be provided a silicon nitride sintered body having a high thermal conductivity of 50 W/m.Math.K or more, and excellence in insulating properties and strength.

A circuit board includes a metal circuit plate, a metallic heat diffusing plate disposed below the metal circuit plate and having an upper surface and a lower surface, a metallic heat dissipating plate below the heat diffusing plate, an insulating substrate disposed between the metal circuit plate and the heat diffusing plate, and an insulating substrate disposed between the heat diffusing plate and the heat dissipating plate. A grain diameter of metal grains contained in the heat diffusing plate decreases from each of the upper surface and the lower surface of the heat diffusing plate toward a center portion of the heat diffusing plate in a thickness direction.