The present invention relates to a semiconductor device, particularly to a multi-chips module (MCM) type semiconductor device adapted to be mounted on a board and to be electrically connected to the board.
JP-A-11-220077 discloses that a coefficient of thermal expansion and so forth is adjusted to restrain a crack of a semiconductor element and/or an under-fill in a flip-chip type semiconductor device. JP-A-2000-40775 discloses a shape of an oblique surface of the under-fill is adjusted to restrain the crack of the semiconductor element.