Method of manufacturing an interlayer connection substrate

A method of manufacturing an interlayer connection substrate comprising:

• providing a first electrode electrically connected to a first pad for a first piercing through hole (TH) on a bonded surface of a first multilayer substrate having the first piercing TH and a first solder bump formed on the first electrode;
• providing a second electrode electrically connected to a second pad for a second piercing TH on a bonded surface of a second multilayer substrate having the second piercing TH at a position opposite the first electrode and a second solder bump formed on the second electrode;
• forming holes in a three-layered sheet derived from applying an adhesive as a resin material that is not completely cured to both surfaces of a core material as a cured resin at positions corresponding to the THs and the solder bumps on the electrodes, respectively;
• and disposing the first and the second multilayer substrates having the respective bonded surfaces facing each other and the three-layered sheet positioned and interposed therebetween, and executing a batch thermocompression bonded through a process of heating and pressing under a vacuum environment to laminate the first multilayer substrate, the second multilayer substrate and the three-layered sheet together, wherein the THs are further drilled to remove resin which flows into the THs after the batch thermocompression bonding process.