Pre-molded substrate, method of manufacturing pre-molded substrate, and hollow type semiconductor device

A method of manufacturing a pre-molded substrate, comprising:

• forming an inner lead and a frame-shaped wiring on a first principal surface of a base plate, the frame-shaped wiring surrounding the inner lead;
• forming an outer lead on a surface of the inner lead opposite from the first principal surface, and forming a first frame-shaped wall on a surface of the frame-shaped wiring opposite from the first principal surface, the first frame-shaped wall surrounding the outer lead;
• sealing the first principal surface, the inner lead, the outer lead, the frame-shaped wiring, and the first frame-shaped wall with resin;
• exposing a back surface of the outer lead and a back surface of the first frame-shaped wall from the resin by polishing the resin from a surface opposite from a surface of the resin that is in contact with the base plate;
• and
• exposing the inner lead, the frame-shaped wiring, and the resin by removing inside of outer periphery of the base plate from a second principal surface which opposes the first principal surface.

A hollow type semiconductor device, comprising:

• a semiconductor element;
• an element mounting portion supporting the semiconductor element;
• an inner lead provided around the element mounting portion, and electrically connected to the semiconductor element;
• a frame-shaped wiring provided around the element mounting portion and the inner lead;
• an outer lead provided in contact with a back surface of the inner lead;
• a first frame-shaped wall provided in contact with a back surface of the frame-shaped wiring;
• a resin sealing body provided between the inner lead and the frame-shaped wiring, and between the outer lead and the first frame-shaped wall;
• a second frame-shaped wall provided in contact with a surface of the frame-shaped wiring opposite from the back surface of the frame-shaped wiring;
• and
• a sealing plate provided in contact with a surface of the second frame-shaped wall opposite from a surface on which the second frame-shaped wall is in contact with the frame-shaped wiring,
• the element mounting portion, the inner lead, and the frame-shaped wiring being exposed on a first surface of the resin sealing body, and the outer lead and the first frame-shaped wall being exposed on a second surface which is a surface opposite from the first surface.