To meet demand for increasingly compact electronic devices, electronic component packages known as POP (Package On Package) in which semiconductor packages are vertically stacked and integrally layered are conventionally used. PLT 1 set forth below describes a multilayer substrate as an example of a prior art electronic component packages.
This prior art electronic component packages includes a first substrate having a first electronic component mounted thereon, a second substrate having a second electronic component mounted thereon, and a frame serving as a connector for electrically coupling the first substrate and the second substrate by joining a periphery of the first substrate and a periphery of the second substrate.