PURPOSE: To prevent corrosion from being produced owing to water entering semiconductor sealing resin and hence improve long-term reliability by constructing a sealing resin frame into a two stage height and providing water- repellent resin on the semiconductor sealing resin.

CONSTITUTION: In a semiconductor mounting substrate 1, there are formed a semiconductor mounting recessed portion 2 at a predetermined location on a double-side copper-clad laminate through boring and a through-hole 6. After a circuit pattern is formed, a solder resist 3 is printed on the substrate and nickel and gold are plated to a semiconductor bonding pad 4 and an exposed conductor portion, and further a sealing resin frame having a two stage height is bonded. Herein, sealing resin 8 is injected to the second stage height and is hardened, and further water-repellent resin 7 is injected up to the second stage and is hardened. Hereby, even if the substrate is left behind in the environment of PCT, water is prevented from entering, and remaining ion in the semiconductor sealing resin is prevented from being produced to sharply improve reliability. Thus, this substrate is useable for a package substrate for mounting a semiconductor chip.