A socket connector includes a metallic stiffener, an insulative housing, a load plate, a load lever and a plurality of washers. The stiffener defines a central opening in a middle portion thereof, the opening being surrounded by two pairs of inner surfaces. The housing defines a recessed conductive zone surrounded by sidewalls. The housing partially received in the opening of stiffener, and sidewalls interferentially engage with the inner surfaces in a direction parallel to the opening. The stiffener defines a plurality of through holes around the opening. Each of the through holes has two washers assembled therein from both sides of the stiffener; and every two washers assembled in a same through hole define a passageway in the middle thereof.