Patent ID: 8355262

Claim:
A method of manufacturing an electronic component built-in substrate, comprising the steps of: mounting an electronic component at a predetermined portion of a first wiring board; performing wire-bonding to electrically connect a bonding pad formed on the first wiring board to an electrode of the electronic component by a bonding wire; coating at least a connection portion between the electrode of the electronic component and the bonding wire with a protection material; arranging the first wiring board and a second wiring board so that one side surface of the second wiring board formed separately from the first wiring board faces one surface of the first wiring board with the electronic component disposed between the first wiring board and the second wiring board, and electrically connecting the first wiring board and the second wiring board to each other by reflowing a solder ball; reflowing the solder ball to clean a portion between the first wiring board and the second wiring board; and sealing a portion between the first wiring board and the second wiring board with a sealing material that is in addition to and distinct from the protection material by casting the sealing material with a capillary action such that the sealing material covers and contacts the one side surface of the second wiring board and the one surface of the first wiring board and fills the portion between the first wiring board and the second wiring board.