Abstract: A threaded fastener and mating driver system is used to apply a uniform torque to the entire fastener body and thereby facilitate removal of stuck fasteners. The driver tool is a two stage driver with one stage driving the inner bore of the fastener and the second stage driving the fastener head. The two driver stages are linked via a series of pins, each pin acting as an individual lever, such that the two drivers apply torque equally to the fastener. The entire driver assembly is housed in a block which can be attached to a standard ratchet or driving tool. The fastener is designed to be installed using a single stage screwdriver and normally has a foil seal covering the bore drive portion of the fastener. If the fastener becomes stuck, the foil seal is broken and the two stage drive system, including a bore driver and a screw head driver, is inserted into the fastener to effect additional removal torque.

Abstract: A flip-chip assembly and method for reducing the stress in its metal interconnections resulting from thermal mismatch includes a detector that has a radiation sensitive circuit on a substrate that is flip-chip connected to a layer of semiconductor material that is provided with a readout circuit. The substrate has a thermal coefficient of expansion (TCE) greater than the semiconductor layer such that operating the detector over a predetermined temperature range would stress the flip-chip connections. A first compensation layer on the readout chip has a TCE greater than the substrate's, and a second compensation layer on the first layer has a TCE approximately equal to the semiconductor layer's. The materials and thicknesses of the compensation layers are selected such that the TCE of a composite structure that includes the semiconductor and compensation layers is approximately equal to the substrate's TCE to avoid the stress over the predetermined temperature range.