In order to ensure the testing

debugging and the long-term stable operation of large-size superconducting quantum interference device(SQUID)magnetometer at liquid helium temperature after tape-out

appropriate packaging protection is required.Firstly

finite element simulation is carried out to study the effect of thermal expansion coefficient of potting adhesive on packaging stress.According to the simulation results

the potting adhesive doped with filler is prepared.The magnetometer is packaged by adopting prepared potting adhesive and tests are carried out.The results show that the lower the coefficient of thermal expansion of potting adhesive

the lower the disconnection rate of leads after temperature cycling

and the intrinsic noise and critical current of the magnetometer do not change significantly after 10 temperature cycles between -196℃ and room temperature.This shows that the proposed packaging method is suitable for the packaging protection of large-size SQUID magnetometer.