Abstract: A multilayer wiring substrate includes a first wiring substrate including a plurality of stacked layers made of a thermosetting resin and having a wiring layer formed between each adjacent layers of the layers in a state in contact with the adjacent layers; a second wiring substrate made of a ceramic; and a joining layer disposed between a back surface of the first wiring substrate and a front surface of the second wiring substrate and configured to join the first wiring substrate and the second wiring substrate to each other. At least a surface of the joining layer adjacent to the second wiring substrate is made of a thermoplastic resin.

Abstract: A wiring board includes: an insulator layer composed mainly of ceramic; a conductor extending through the insulator layer in a thickness direction thereof; and an electrode pad disposed on a first surface of the insulator layer and connected electrically with the conductor, wherein: the electrode pad includes through holes extending through the electrode pad in a thickness direction thereof; and each of the through holes is positioned to avoid overlapping with the conductor in the thickness direction of the insulator layer.

Abstract: A wiring board includes: an insulator layer composed mainly of ceramic; a conductor extending through the insulator layer in a thickness direction thereof; and an electrode pad disposed on a first surface of the insulator layer and connected electrically with the conductor, wherein: the electrode pad includes through holes extending through the electrode pad in a thickness direction thereof; and each of the through holes is positioned to avoid overlapping with the conductor in the thickness direction of the insulator layer.