I have sensitive signal path on my layout that need to be shielded by the analog ground,
could you please tell me how to shield?,
does shielding mean that I will route a higher metal layer over my signal and connect it to ground ?
Ideally, you should shield your clock lines so that they don't couple to other nodes.
You can do that by making M1 (GND) - M2 (clock lines) - M3 (GND) to shield them. But you should consider that there will be more parasitic capacitances in your clock lines and therefore you should account for that when driving those lines.