| 摘要 |
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. |
