US Patent 7666692 Semiconductor device, its manufacture method and electronic component unit

A LED chip having first and second electrodes on opposite principal surfaces, is bonded to a substrate through a composite bonding layer. The composite bonding layer is formed when a support substrate including the substrate and a first bonding layer is bonded to a lamination structure including the LED, the first electrode and a second bonding layer. The first or second bonding layer contains at least part of eutectic composition. At least one of the support substrate and the lamination structure includes a diffusion material layer. The composite bonding layer is formed in such a manner that eutectic material contents are mixed with the other to form a first mixture, and that the first mixture is mixed with diffusion material to form a second mixture having a melting point higher than a melting point of the first mixture.