A method of manufacturing a circuit board includes: providing a substrate including a bottom layer and a resin layer over the bottom layer, the resin layer including a first surface in contact with the bottom layer and a second surface opposite to the first surface; forming a plurality of vias through the resin layer; depositing a first metal layer in the vias, the first metal layer filling a portion of each of the vias; depositing a second metal layer over the first metal layer and in the vias; forming a patterned metal layer over the second metal layer and extending from each of the vias to a position over the second surface; separating the bottom layer and the resin layer; and removing a portion of the resin layer from the first surface, so that the first metal layer protrudes from the resin layer.

Flexible electrical devices comprising electrode layers on softening polymers and methods of manufacturing such devices, including lift-off processes for forming electrodes on softening polymers, processes for forming devices with a patterned double softening polymer layer, and solder reflow processes for forming electrical contacts on softening polymers.

An electronic assembly includes a substrate having a first surface and a second surface opposing the first surface. The electronic assembly includes first electronic component disposed on the first surface of the substrate, and a first encapsulant encapsulating the first electronic component on the first surface of the substrate. The electronic assembly also includes a second electronic component disposed on the second surface of the substrate, and a second encapsulant encapsulating the second electronic component on the second surface of the substrate such that the second electronic component is completely submerged below a second assembly surface of the second encapsulant. The electronic assembly further includes a groove positioned on the second assembly surface of the second encapsulant, and a solder joint having a portion protruding from the groove for establishing an electrical connection with an external component.

A stackable via package includes a substrate having an upper surface and a trace on the upper surface, the trace including a terminal. A solder ball is on the terminal. The solder ball has a solder ball diameter A and a solder ball height D. A via aperture is formed in a package body enclosing the solder ball to expose the solder ball. The via aperture includes a via bottom having a via bottom diameter B and a via bottom height C from the upper surface of the substrate, where A<B and 0=<C<D. The shape of the via aperture prevents solder deformation of the solder column formed from the solder ball as well as prevents solder bridging between adjacent solder columns.

A method of forming a heat spreader on a printed circuit board (PCB), having a power dissipating component operably coupled thereto, includes attaching a thermally and electrically conductive structure, to a first side of the PCB to define a first PCB region that includes the component and a second PCB region without. The underside of the component is underfilled to electrically insulate its solder contacts. A first protective layer is applied to the second region of the PCB. A conductive plating membrane is deposited to the first region, the second region, and to the structure. A second protective layer is applied over a portion of the conductive plating membrane that overlays the second region, leaving exposed the rest of the conductive plating membrane. An electrically and thermally conductive layer is electroplated over the exposed areas of the conductive plating membrane, to form a heat exchanger within the first region.

Applying a solderable surface to conductive ink may include partially curing a conductive ink trace; applying, to the partially cured conductive ink trace, a conductive paste comprising conductive particles; and curing the partially cured conductive ink trace and the conductive paste.

A set of features for a product is identified. It is determined that preventing an electrical connection at a ball-grid-array location on a ball-grid-array assembly of the product would result in the set of features. The ball-grid-array location is established as a target BGA location based on that determination. Suction is applied to a via at the target BGA location during reflow of the ball-grid-array assembly. With that application of suction, a solder ball at the target BGA location is drawn into the via.

Examples are disclosed related to forming solder joints between printed circuits by using radiant heat. One example provides a method of manufacturing an electronic device, the method comprising aligning a contact of a first printed circuit with a via of a second printed circuit. The method further comprises applying radiant heat via an infrared light source to a second surface of the second printed circuit, the radiant heat incident on the via to cause the via to conduct heat to solder located at an interface of the contact and the via, and after heating the solder to reflow, cooling the solder, thereby forming a solder joint between the contact of the first printed circuit and the via of the second printed circuit.

Embodiments of the invention include flexible circuit board interconnections and methods regarding the same. In an embodiment, the invention includes a method of connecting a plurality of flexible circuit boards together comprising the steps applying a solder composition between an upper surface of a first flexible circuit board and a lower surface of a second flexible circuit board; holding the upper surface of the first flexible circuit board and the lower surface of the second flexible circuit board together; and reflowing the solder composition with a heat source to bond the first flexible circuit board and the second flexible circuit board together to form a flexible circuit board strip having a length longer than either of the first flexible circuit board or second flexible circuit board separately. In an embodiment the invention includes a circuit board clamp for holding flexible circuit boards together, the clamp including a u-shaped fastener; a spring tension arm connected to the u-shaped fastener; and an attachment mechanism connected to the spring tension arm. Other embodiments are also included herein.

Flexible electrical devices comprising electrode layers on softening polymers and methods of manufacturing such devices, including lift-off processes for forming electrodes on softening polymers, processes for forming devices with a patterned double softening polymer layer, and solder reflow processes for forming electrical contacts on softening polymers.