An interconnect substrate includes a substrate, and a first connection terminal and a second connection terminal that are disposed on a surface of the substrate, wherein the first connection terminal includes a first columnar electrode and a first bump disposed on the first columnar electrode, the first columnar electrode having a flat or convex surface and having a first diameter, wherein the second connection terminal includes a second columnar electrode and a second bump disposed on the second columnar electrode, the second columnar electrode having a concave surface and having a second diameter larger than the first diameter, and wherein a melting point of the first bump and the second bump is lower than a melting point of the first columnar electrode and the second columnar electrode.