MULTILAYER SUBSTRATE AND ELECTRONIC DEVICE USING THE SAME

PROBLEM TO BE SOLVED: To improve the heat transfer performance from second inner layer wiring to a pattern for a heat radiation member.SOLUTION: A heat radiation pattern 53 is insulated from second inner layer wiring 52. In the heat radiation pattern 53, heat conductivity with the second inner layer wiring 52 becomes larger than heat conductivity between the second inner layer wiring 52 and a pattern 72 for a heat radiation member. The heat radiation pattern 53 is formed on a rear surface 20b of a core layer 20. A via 102, which thermally connects the heat radiation pattern 53 with the pattern 72 for the heat radiation member and has a material having heat conductivity higher than a second build-up layer 40, is formed on the second build-up layer 40. 【課題】第２内層配線から放熱部材用パターンへの伝熱性を向上する。【解決手段】コア層２０の裏面２０ｂに、第２内層配線５２と絶縁され、かつ第２内層配線５２と放熱部材用パターン７２との間の熱伝導率より第２内層配線５２との間の熱伝導率が大きくなる放熱パターン５３を形成する。そして、第２ビルドアップ層４０に、放熱パターン５３と放熱部材用パターン７２とを熱的に接続し、第２ビルドアップ層４０よりも熱伝導率が高い材料を有するビア１０２を形成する。【選択図】図１