According to an aspect of the present disclosures, a method of making a flexible printed circuit board, which includes a base film having an insulating property, a conductive pattern disposed on either one or both surfaces of the base film, and a cover layer covering a conductive-pattern side of a laminated structure inclusive of the base film and the conductive pattern, includes a superimposing step of superimposing a cover film on the conductive-pattern side of the laminated structure, the cover film having a first resin layer and a second resin layer that is laminated to an inner side of the first resin layer and that softens at a lower temperature than does the first resin layer, and a pressure bonding step of vacuum bagging the laminated structure and the cover film at a temperature higher than a softening temperature of the second resin layer.

An interlayer connective structure is suitable for being formed in a wiring board, in which the wiring board includes two traces and an insulation part between the traces. The insulation part has a through hole. The interlayer connective structure located in the through hole is connected to the traces. The interlayer connective structure includes a column and a pair of protuberant parts. The protuberant parts are located at two ends of the through hole respectively and connected to the column and the traces. The protuberant parts stick out from the outer surfaces of the traces respectively. Each of the protuberant parts has a convex curved surface, in which the distance between the convex curved surface and the axis of the through hole is less than the radius of the through hole.

A wiring circuit board includes a porous insulating layer, and a first conductive layer sequentially toward one side in the thickness direction. The first conductive layer includes a first signal wire and first ground wires. Each of the first ground wires is thicker than the first signal wire.

The main technical problem solved by the present disclosure is to provide a circuit board preparation method. The method includes: obtaining a to-be-processed plate comprising an insulating layer, a first copper layer, a second copper layer opposite to the first copper layer, a blind metalized hole, and a first tab facing the blind metalized hole; obtaining a white insulating material; laminating the white insulating material to a surface of the insulating layer, a surface of the first copper layer, a surface of the first tab, and a surface of the second copper layer to form a first white insulating medium layer and a second white insulating medium layer opposite to the first while insulating medium layer; and performing surface polishing for the first white insulating medium layer and grinding the first white insulating medium layer until the first tab is exposed to form a first white reflective layer.

A multilayer printed circuit board having a stackup including an upper half of the stackup and a lower half of the stackup, the multilayer printed circuit board having a top exposed surface and a bottom exposed surface, a first trace and via structure, having one portion disposed on the top exposed surface and another portion disposed within the upper half of the stackup, a second trace and via structure, having one portion disposed on the top exposed surface and another portion disposed within the upper half of the stackup, and first electrical components and second electrical components disposed on the top exposed surface of the multilayer printed circuit board and associated, respectively, with the first trace and via structure and the second trace and via structure, wherein the first electrical components are mounted orthogonally with respect to the second electrical components.

A multilayer printed circuit board having a stackup including an upper half of the stackup and a lower half of the stackup, the multilayer printed circuit board having a top exposed surface and a bottom exposed surface, a first trace and via structure, having one portion disposed on the top exposed surface and another portion disposed within the upper half of the stackup, a second trace and via structure, having one portion disposed on the top exposed surface and another portion disposed within the upper half of the stackup, and first electrical components and second electrical components disposed on the top exposed surface of the multilayer printed circuit board and associated, respectively, with the first trace and via structure and the second trace and via structure, wherein the first electrical components are mounted orthogonally with respect to the second electrical components.

A method for designing PCB pads: using a drill bit of a first size to drill through a PCB from a first side; using a drill bit of a second size to back-drill a second side of the PCB so as to form a pyramid-shaped through hole; setting the connection means of a second layer and third layer of an inner layer of the PCB that comprises the pyramid-shaped through hole to full connection; and disposing a pad of a third size on a first layer of the inner layer, and disposing a pad of a fourth size on the last layer of the inner layer, wherein the fourth size is bigger than the third size, the fourth size is bigger than the second size, the second size is bigger than the first size, and the third size is bigger than the first size.

A structure may include a first material, a second material joined to the first material at a junction between the first and second materials, and one or more media extending across the junction to form a continuous interconnect between the first and second materials, wherein the first and second materials are heterogeneous. The structure may further include a transition at the junction between the first and second materials. The one or more media may include a functional material which may be electrically conductive. The structure may further include a third material joined to the second material at a second junction between the second and third materials, the media may extend across the second junction to form a continuous interconnect between the first, second, and third materials, and the second and third materials may be heterogeneous.

A structure may include a first material, a second material joined to the first material at a junction between the first and second materials, and one or more media extending across the junction to form a continuous interconnect between the first and second materials, wherein the first and second materials are heterogeneous. The structure may further include a transition at the junction between the first and second materials. The one or more media may include a functional material which may be electrically conductive. The structure may further include a third material joined to the second material at a second junction between the second and third materials, the media may extend across the second junction to form a continuous interconnect between the first, second, and third materials, and the second and third materials may be heterogeneous.

A component carrier with an electrically insulating layer having a front side and a back side, a first and a second electrically conductive layer covering the front side and the back side of the electrically insulating layer, respectively. A through hole extends through both electrically conductive layers and the electrically insulating layer. An overhang is formed along one of the electrically conductive layers and sidewalls of the electrically insulating layer structure delimiting the through hole. An annular plating layer covers the sidewalls and fills part of the overhang such that a horizontal extension of the overhang after plating is less than 20 μm and/or such that a ratio between a horizontal extension of the overhang after plating and a width of a first window through the first electrically conductive layer and/or a width of a second window through the second electrically conductive layer is smaller than 20%.