For both the one piece heatsink or individual heat spreaders, the contact surface should be properly designed to ensure maximum contact on the die or lid of the device. Where multiple density devices are used the contact surface or island can be specified so that it is compatible with all die sizes in the same package. The island height should ensure that the pressure applied to the heatsink is on the die and that the stiffener ring is not contacted.
Figure 1. Heatsink Pedestal with Etch Pattern
