Disclosed herewith a socket connector configured with an insulative housing defining a mating interface surrounded with peripheral walls and a mounting surface. A plurality of passageways is defined between the mating interface and the mounting surface and having an opening at the mounting surface. The insulative housing includes an encampment associated with each of the passageway at the mounting surface, and includes an extension crossing over an inner wall of the passageway to substantially narrow the opening of the opening. The socket connector furthers includes a plurality of contact terminals each received in the passageway and further includes a curvilinear solder portion extending beyond the mounting surface. And the socket connector further is incorporated with a plurality of solder balls each disposed between the encampment and the curvilinear solder portion.