In recent years, the trend toward miniaturization in electronics has given rise to the need for establishing electrical connections between ever smaller components having ever increasing numbers of contact sites. This situation is particularly acute in the computer industry, in which hundreds of thousands of switching circuits can now be disposed on a single chip. As the number of switching circuits on these chips rises, so does the number of contacts through which electrical signals pass into and out of the chip to provide signal communication with other chips and devices which may be mounted, for example, on a common circuit board.
In attempts to provide signal communication to such chips, the chips may be mounted singly or in multiple chip modules in which the electrical leads terminate on the surface of the chip package in a fixed array of contact pads. The circuit board is equipped with a corresponding array of contact pads, and an array of connector elements is disposed between the chip package and the circuit board to provide the necessary electrical connections between the respective pads. For example, U.S. Pat. No. 4,838,801 to Bertoglio et al, dated Jun. 13, 1989, discloses a leadless component socket in which an array of bore holes in a plate-like socket body matches corresponding arrays of electrical contacts on the components to be electrically connected. In each bore hole is disposed a two part connector element with one part extending from each end of the bore hole toward a corresponding electrical contact pad. The two pieces are fitted together so that when the respective contact pads are brought into position, a springing force biases the two parts toward the respective contact pad surfaces.
U.S. Pat. No. 4,961,709 to Noschese dated Oct. 9, 1990, discloses an electrical connector for establishing a connection between spaced printed circuit boards. The connector comprises a metal block dispersed between the circuit boards and equipped with an array of holes. In each hole is disposed a contact spring formed form a stamped Y-shaped member which is spirally coiled with the ends of the arms of the Y wrapped internally in the coil. The base of the Y is disposed in the outermost portion of the coil, and the parts of the arms which protrude from either side of the coil are trimmed to form rounded tips.