A flip chip semiconductor device having an improved structure and a method of manufacturing the flip chip semiconductor device, in which a semiconductor chip can be more securely joined to a lead frame while preventing contact defects between the two. The flip chip semiconductor device includes: a semiconductor chip having electrode pads formed on one side; conductive bumps formed on the electrode pads of the semiconductor chip; and a lead frame including a plurality of leads, the ends of which are electrically connected to the conductive bumps, wherein each of the leads has at least one groove formed thereon, and a solder plating layer is provided on the leads in and about the groove and melted to secure the connection with the conductive bumps.