Abstract: A heat sink assembly comprises a heat sink and a retainer clip for attachment to an electronic package or semiconductor device so as to dissipate heat from such device. The heat sink may comprise a flat base with a plurality of upwardly extending fins. The fins will define at least one channel. The retainer clip includes two parts. One part is an elongated, resilient, metal strap that has holding means at each end for engaging a semiconductor socket, or a semiconductor module, so as to secure the retainer clip and heat sink to the device or module. The retainer clip also includes a cam-type latch which is pivotally positioned in the middle of the elongated strap and includes an arm and a cam. The cam has a bearing surface which is spaced from the axis of the elongated member a distance greater than the distance between the elongated member and the upper surface of the heat sink base when in the initially assembled position.