1.I flooded the hole through solder, it was not working still. I did X-Ray scanning of that particular area, observed that in the n.working board the inner copper wall was not uniform completely. In working board it was uniform. I attached the capture of the hole in n.working board. One more thing, the assembly vendors informed that, the RTC battery is connected through hand soldering (other components through Machine soldering) and the temperature the hole can withstand without any damage is 340 deg C. Now m doubting this, we can not expect accuracy with the manual soldering, the temperature might have exceeded the threshold or distributed randomly.