PURPOSE: To provide a semiconductor device wherein the flatness and the surface roughness of a bonding face (a mounting face) for a semiconductor chip are good and to provide its manufacturing method.

CONSTITUTION: 1) A semiconductor device is featured by providing the following: a first insulating substrate 20; a semiconductor chip which is bonded to the surface of the substrate 20; second insulating substrates 21, 22 in which a through hole for housing the semiconductor chip is made and which are bonded to the surface of the first insulating substrate 20; and third insulating substrates 23, 24 which are bonded to the rear surface of the first insulating substrate 20 and whose shape and material are the same as those of the second insulating substrates 21, 22. 2) The manufacturing method, of a semiconductor device, which is provided with a process wherein the face of a substrate 20 to which a semiconductor chip is bonded is ultrasonically machined 31 to 35. 3) A semiconductor device wherein sidewalls on the side of short sides on the face of a substrate to which a semiconductor chip is bonded are bonded to side faces of the substrate.