How To Remove This from PCB
What you are looking at it the bottom of a silicon die - the silver is actually pure crystalline silicon (the un-patterned side of the original wafer) which has then been etched to add part identification markings.


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On the other side of the die from what you have photographed (actually the top of it), will be the transistors and interconnects. The very top layer of the die will have a series of bond pads. The whole thing is flip-chip bonded to the substrate/interposer either chemically or with a solder-like substance - hence the bottom of the die is on the top after mounting.

The epoxy around the edge is there simply to stop the ingress of dirt and fluids (e.g. water) that may otherwise damage the die. It may also provide some mechanical strain relief to avoid stresses on the die from vibration, etc.

Any attempt to remove it will almost certainly destroy the chip and possibly the interposer, especially as there is no way of knowing how many bond pads are underneath, and how they are bonded to the interposer.