Electronic device substrate and its fabrication method, and electronic device and its fabrication method

摘要

An electronic device substrate is formed of a thin-plate reinforcing substrate; an external connection wiring layer stacked on the reinforcing substrate, and comprising an electrical insulation provided on the reinforcing substrate, an opening formed in the electrical insulation, a first conductor pattern and a via-hole conductor provided in the opening and formed integrally with each other; and a second conductor pattern formed on the opposite side of the electrical insulation to the reinforcing substrate, and at least partially electrically connected to the via-hole conductor.