Mounting board and electronic device using the same

摘要

Wiring electrodes are formed on a first principal surface of a base substrate. An insulation film partially covers the first principal surface of the base substrate and the wiring electrodes. The insulation film has opening portions where the base substrate and the wiring electrodes are not coated with the insulation film. An electronic component having bump electrodes is mounted on the mounting board by connecting the bump electrodes with the wiring electrodes in the opening portions. A gap between the first principal surface of the base substrate and the electronic component is filled with sealing resin. The opening portions are substantially orthogonal to the longitudinal direction of the wiring electrodes. The ratio of the minimum width of a portion of the base substrate exposed at each of the opening portions to the thickness of the insulation film may advantageously be greater than or equal to 2.