A structure includes a first package and a second package. The second package is coupled to the first package by one or more connectors. Epoxy flux residue is disposed around the connectors and in contact with the connectors. A method includes providing a first package having first connector pads and providing a second package having corresponding second connector pads. Solder paste is printed on each of the first connector pads. Epoxy flux is printed on each of the solder paste. The first and second connector pads are aligned and the packages are pressed together. The solder paste is reflowed to connect the first connector pads to the second connector pads while leaving an epoxy flux residue around each of the connections.