Abstract: An insulating substrate has an insulating plate, an obverse metal pattern, and a reverse metal pattern. A semiconductor chip is mounted on the obverse metal pattern of the insulating substrate. A main terminal is joined to a main electrode on an upper surface of the semiconductor chip. A signal terminal is connected to a control electrode on the upper surface of the semiconductor chip by a wire. A sealing resin seals the insulating substrate, the semiconductor chip, the wire, and a part of the main terminal and a part of the signal termina. The reverse metal pattern protrudes from a lower surface of the sealing resin. A side surface and a lower surface of the reverse metal pattern are exposed from the sealing resin. An exposed surface of the reverse metal pattern is modified and hardened. The reverse metal pattern has a convex shape which bulges downward.

Abstract: An azetidine derivative is provided which includes 3,3-dihydroxyazetidine represented by Chemical Formula (I) or a salt thereof: ##STR1## A composition containing the azetidine derivative, and a process for producing the azetidine derivative are also provided. The azetidine derivative is a novel compound, and is useful for promoting bifidobacterium divisional multiplication.