Patent ID: 7061100

Claim:
A semiconductor built-in millimeter-wave band module comprising: an electrical insulating substrate that is made of a mixture containing an inorganic filler and a thermosetting resin; a high thermal conductivity substrate that is made of a dielectric material having thermal conductivity higher than thermal conductivity of the electrical insulating substrate and is laminated on one surface of the electrical insulating substrate; a plurality of wiring patterns that is formed on the high thermal conductivity substrate and the electrical insulating substrate; a semiconductor device operating at millimeter-wave band, which is arranged inside of the electrical insulating substrate, is packaged on the high thermal conductivity substrate in a face-up manner, and is connected electrically with the wiring patterns; and a distributed constant circuit element and an active element that are provided on the semiconductor device, wherein a void with dimensions smaller than dimensions of the semiconductor device is provided inside of the electrical insulating substrate, the void surrounds a surface of the distributed constant circuit element or a surface of the active element, the void is filled with a material having a dielectric constant of substantially 1, the void is uniform around the distributed constant circuit element or active element, and a minimum space between a wall of the void and the respective distributed constant circuit element or the active element is 100 μm or more.