An LGA connector (1) comprises a housing (11) for receiving a number of contacts (12), a stiffener (13) partly covering and reinforcing the housing. The stiffener comprises a pair of lateral sides (130), a front end (131) and a rear end (132), and a central cavity (133) disposed therebetween. The sides, the front end and the rear end each define a bottom wall (134) thereof, thereby around the central cavity. A plurality of separately and uniformly protrusions (135) is formed on a bottom surface of the bottom wall. The protrusion and the bottom wall are integrally formed as a single piece by stamping. Thus, the connector is soldered on a circuit board (3) via solder balls (16, 17) on the contacts and the protrusions, thereby preventing the connector from inclining downwardly during in reflow process because of the connecting force between the connector and the board increased.