Semiconductor device and manufacturing method thereof

A semiconductor device comprising:

• a first chip including a first wire, a first connection pad electrically connected to the first wire, and a first dummy pad;
• and
• a second chip including a second wire, a second connection pad electrically connected to the second wire and joined to the first connection pad, and a second dummy pad joined to the first dummy pad, wherein
• the first dummy pad is electrically connected to the first wire, or the second dummy pad is electrically connected to the second wire.

A manufacturing method of a semiconductor device, comprising:

• forming a plurality of concave portions in an interlayer dielectric film formed on a first wire provided on a first wafer and embedding a metal into the concave portions, to form a first connection pad electrically connected to the first wire and a first dummy pad;
• forming a plurality of concave portions in an interlayer dielectric film formed on a second wire provided on a second wafer and embedding a metal into the concave portions, to form a second connection pad electrically connected to the second wire and a second dummy pad;
• and
• joining the first connection pad and the second connection pad to each other and joining the first dummy pad and the second dummy pad to each other, wherein
• the concave portions are formed in such a manner that a thickness of the first dummy pad is smaller than a thickness of the first connection pad and a thickness of the second dummy pad is also smaller than a thickness of the second connection pad, or the thickness of the first dummy pad is smaller than the thickness of the first connection pad or the thickness of the second dummy pad is smaller than the thickness of the second connection pad.