Heat sink board and manufacturing method thereof

摘要

A heat sink board having a first heat sink and a second heat sink with a smaller linear expansion coefficient than that of the first heat sink and being bonded to the first heat sink to form the heat sink board. The second heat sink is fitted to the first heat sink, and a material of the first heat sink in the vicinity of a boundary between the fitted heat sinks is plastically deformed for close adhesion to the second heat sink. A forming method makes bonding between the first and second heat sinks possible at room temperature, and the heat sink board made of a composite member having a high flat-surface accuracy can be easily and reliably obtained.