A burn-in socket for receiving an IC package comprises a socket body, a plurality of contacts mounted in the socket body and an actuator movably mounted upon the socket body. Each contact in the socket body includes a pair of clipping arms with tip portions at free ends thereof respectively. Solder balls attached to the bottom of the IC package are respectively clipped between the pair of the tip portions and thus the IC package should be brought into electrical contact with the contacts of the burn-in socket. The tip portion is plated with a Pd—Co layer for reducing the attachment of the Sn and preventing the impedance of the contacts to increase. Meanwhile, the IC package can be sucked up successfully without absorption from the contacts of the burn-in socket.