Semiconductor device and manufacturing method of the same

A semiconductor device, comprising:

• a bonded substrate having a first conductive layer and a second conductive layer arranged deeper than the first conductive layer, wherein the bonded substrate includes a first substrate including the first conductive layer and a second substrate including the second conductive layer;
• a large-diameter concave portion having, on a main side of the bonded substrate, an opening sized to overlap at least a part of an interconnect of the first conductive layer and at least a part of an interconnect of the second conductive layer in a plane section of the bonded substrate;
• a small-diameter concave portion extended from the large-diameter concave portion;
• a conductive member provided in a connection hole made up of the large and small-diameter concave portions, wherein the first conductive layer is formed in a first interlayer insulating film, and wherein a portion of the small-diameter concave portion formed in the first interlayer insulating film is formed only in the first interlayer insulating film.

A semiconductor device, comprising:

• a first substrate, including:
• a first semiconductor, the first semiconductor having a first surface and a second surface opposite the first surface;
• and
• a first interconnection layer, wherein the first interconnection layer is formed on the second surface of the first semiconductor and includes at least a first interconnect and an insulating film;
• a second substrate, including:
• a second semiconductor, the second semiconductor having a first surface and a second surface opposite the first surface;
• and
• a second interconnection layer, wherein the second interconnection layer is formed on the first surface of the second semiconductor and includes at least a second interconnect;
• a joint section, wherein the first interconnection layer of the first substrate is joined to the second interconnection layer of the second substrate at the joint section;
• a connection hole, including:
• a large diameter concave portion, wherein the large diameter concave portion extends from the first surface of the first semiconductor layer to the first interconnection layer, wherein the large-diameter concave portion includes a first step-like portion and a second step-like portion;
• and
• a small diameter concave portion, wherein the small diameter concave portion extends from the first interconnection layer to the second interconnection layer;
• and
• a conductive member, wherein the conductive member is provided in the connection hole, wherein the conductive member connects the first interconnection layer to the second interconnection layer, wherein the first step-like portion is electrically connected to at least a portion of the first interconnection layer and the second step-like portion is connected solely to a portion of the insulating film, and wherein the small-diameter concave portion is electrically connected to the second interconnection layer.