Can anyone help me how to convert 100mV AC to 1.5V DC without using any external power supplies
Firstly can anyone suggest me a CMOS circuit to convert 100 mV of AC to
DC. And DC to DC boosting is 2nd phase of my circuit.

Wrong order - boost the 100 mV AC to something like a couple of volts AC using a step-up transformer then rectify to DC.
Wrong tech - it doesn't need CMOS to do this. Regular silicon diodes will rectify the upgraded AC signal to produce a couple of volts of DC then a fairly average DC-to-DC converter can take it from there (CMOS or otherwise).