Ultra-thin card-type semiconductor device having an embredded semiconductor element in a space provided therein

A semiconductor device, comprising:

• a film insulating substrate having a device hole;
• a wiring layer formed on at least one main face of the insulating substrate and a group of leads whose one end is connected to the wiring layer and the other end is protruded into the device hole;
• a semiconductor element which has a thickness smaller than the insulating substrate with its each electrode pad electrically connected to respective leading ends of the group of leads, the semiconductor element being fully embedded into the device hole of the insulating substrate;
• exterior layers which are laminated on both faces of the insulating substrate;
• and
• an insulating resin layer sealing the connected portions between the electrode pads of the semiconductor element and the leads,
• wherein the insulating resin layer is formed in such a manner that at least a part of a side surface of the semiconductor element is covered, and
• a first air portion is formed between the insulating resin layer and the insulating substrate in the device hole thereof.