A printed structure comprises a device comprising device electrical contacts disposed on a common side of the device and a substrate non-native to the device comprising substrate electrical contacts disposed on a surface of the substrate. At least one of the substrate electrical contacts has a rounded shape. The device electrical contacts are in physical and electrical contact with corresponding substrate electrical contacts. The substrate electrical contacts can comprise a polymer core coated with a patterned contact electrical conductor on a surface of the polymer core. A method of making polymer cores comprising patterning a polymer on the substrate and reflowing the patterned polymer to form one or more rounded shapes of the polymer and coating and then patterning the one or more rounded shapes with a conductive material.

A component built-in board comprises stacked therein a plurality of printed wiring bases having a wiring pattern and a via formed on/in a resin base thereof, and comprises an electronic component built in thereto, wherein at least a portion of the plurality of printed wiring bases include a thermal wiring in the wiring pattern and include a thermal via in the via, at least one of the plurality of printed wiring bases has formed therein an opening where the electronic component is built, and has formed therein a heat-conducting layer and closely attached to a surface on an opposite side to an electrode formation surface of the electronic component built in to the opening, and the electronic component is fixed in the opening by an adhesive layer stacked on the heat-conducting layer, via a hole formed in a region facing onto the opening of the heat-conducting layer.

A component built-in board comprises stacked therein a plurality of printed wiring bases having a wiring pattern and a via formed on/in a resin base thereof, and comprises an electronic component built in thereto, wherein at least a portion of the plurality of printed wiring bases include a thermal wiring in the wiring pattern and include a thermal via in the via, at least one of the plurality of printed wiring bases has formed therein an opening where the electronic component is built, and has formed therein a heat-conducting layer and closely attached to a surface on an opposite side to an electrode formation surface of the electronic component built in to the opening, and the electronic component is fixed in the opening by an adhesive layer stacked on the heat-conducting layer, via a hole formed in a region facing onto the opening of the heat-conducting layer.