In this slide, the effects of uneven components are shown. In the first example, a concave device makes contact with the TIM only at the edges. This is an example of the TIM not filling the interfacial gap correctly. In the second example the component heat spreader has a convex bump on the center. This allows for contact in the center of the package above the die. Applying ink to a component before attaching a taped on heat sink is a good diagnostic tool to ensure correct contact.