Circuit board and a semiconductor device using the same

PROBLEM TO BE SOLVED: To improve the reliability of a flip-chip bonding portion.SOLUTION: A circuit board 1 comprises: a plurality of electrode portions 1e that are electrically connected to a plurality of bumps 3 provided in a semiconductor chip 2; and a plurality of openings 1d in which each of the multiple electrode portions 1e is arranged. The electrode portion 1e comprises a first electrode portion 1ea and a second electrode portion 1eb. The second electrode portion 1eb has a protrusion 1ec protruding from the first electrode portion 1ea along a bottom surface 1da of the opening 1d. The volume of the second electrode portion 1eb is larger than that of the first electrode portion 1ea.