The metal heat spreader and small PCB that make up the external features of an Intel CPU are terraced slightly. That’s done to separate two distinct resting areas on the CPU: the retention bracket that holds the CPU into the socket, and the heatsink that sits on top of the CPU’s heat spreader. Specifically, the socket retention bracket sits on top of the middle tier made of metal, while the heatsink sits on the top tier. That way, the two don’t touch.
There is also a small notch here that works with a symetical notch on the other side of the chip as well as the gold triangle we covered earlier to help you place the CPU in its socket correctly.