Disclosed is a semiconductor device comprising a semiconductor substrate, an under-bump pattern on the semiconductor substrate and including a first metal, a bump pattern on the under-bump pattern, and an organic dielectric layer on the semiconductor substrate and in contact with a sidewall of the bump pattern. The bump pattern includes a support pattern in contact with the under-bump pattern and having a first width, and a solder pillar pattern on the support pattern and having a second width. The first width is greater than the second width. The support pattern includes at least one of a solder material and an intermetallic compound (IMC). The intermetallic compound includes the first metal and the solder material.