SUBSTRATE STRUCTURE

摘要

PROBLEM TO BE SOLVED: To improve electric connection reliability. SOLUTION: A part of conductor 17A accommodated in a hole 16A formed in a substrate 18A is exposed to the outside on at least one surface out of peripheral surfaces of the substrate 18A. As a result, gas in the hole 16A which is generated when thermal hysteresis of reflow or the like is applied is discharged to the outside of the substrate 18A through the exposed part of the conductor 17A.