1. Field of the Invention
The present invention relates to a substrate with a built-in component, an electronic component being built in the substrate with a built-in component, and a method for manufacturing the same.
2. Description of the Related Art
A substrate described in, for example, Japanese Unexamined Patent Application Publication No. 2007-305674 is a known substrate with a built-in component. In the following, the substrate with a built-in component described in Japanese Unexamined Patent Application Publication No. 2007-305674 will be described with reference to FIG. 8. FIG. 8 is a cross-sectional view showing the substrate with a built-in component.
A substrate with a built-in component 101 is formed by stacking a plurality of insulating layers 102, which are made of a thermoplastic resin, and by performing thermocompression bonding thereon. Wiring conductors 103, which are made of copper foil or the like, are formed on some of the insulating layers 102. The wiring conductors 103 are electrically connected by vias 104 to lands 105, which are formed on a main surface of the substrate with a built-in component and on the surface opposite the main surface. An electronic component 106 is built in the inside of the substrate with a built-in component 101. Electrodes 106a of the electronic component 106 are electrically connected to the wiring conductors 103 and the lands 105 by the vias 104.
In the case where a plurality of resin sheets composing the substrate are bonded by thermocompression, there is a possibility that wiring conductors and vias are displaced and open defects and short defects occur in such a substrate with a built-in component as a result of the resin flow of a resin sheet in the plane direction or in the thickness direction. A problem has been newly discovered in which the above-described problem occurs more often, particularly in the case where wiring in the periphery of a built-in component is improved to be finer and denser. The resin flow is particularly large in the periphery of the built-in component because the resin in the periphery of the built-in component moves so as to fill the gap between the component and the resin.