ends 86 and 94 of the spring 62 and are positioned such that the spring 62 fits between the center fins 66 of the heatsink 28 the aforementioned structure allows the heatsink 28 to be centrally spring loaded over the module 12 by tightening a screw 74 into the center hole 70 of the spring 62 the further the screw 74 is screwed into the spring 62 the more the center of the spring 62 deflects and the higher the force applied to the heatsink 28 and correspondingly the higher the force between the heatsink 28 and the module 12 the central location of the force application assures uniformity of pressure of the thermally conductive material and the corresponding uniformity of the thermal interface gap 44 several methods may be employed to create and control the force such as turning the screw 74 a predefined number of rotations or turning the screw 74 until its head bottoms out against the spring 62 for example the heatsink 28 may be massive enough to require additional structural attachment to for example the stiffener 50 than is provided by the spring 62 alone therefore embodiments may lock the heatsink 28 to the stiffener 50 through the.