The next thing we need to do is to solder the two layers together. We need to get the lower layer reballed first. Put the lower layer into the reballing mold and get the BGA Reballing Stencil in position.

Place the mold onto the base. The stencil is tightly attached to the lower layer because of the magnetic structure of the base. Then we smear some low-temp solder paste on the stencil and wipe off excess solder paste with a lint-free wipe.