Enhanced ceramic ball grid array using in-situ solder stretch with clip

Apparatus for forming an elongated solder joint between two solder interconnected substrates in an electronic module comprising:

• a stretching device employing an expandable metal disc adapted to exert a separating force to a first substrate containing a plurality of solder bumps;
• means for positioning the first substrate adjacent a second substrate to be interconnected thereto;
• means for reflowing the solder to form an interconnected solder joint between the first substrate and the second substrate;
• means for separating the first substrate and second substrate to elongate the solder joint by expanding the expandable metal disc of the device;
• and
• means for cooling the substrates to form the elongated solder joint.

A stretching device for forming an elongated solder joint between two solder interconnected substrates comprising:

• a clamping bridge having a clamping bridge connecting base and opposed clamping means extending below the lower surface of the clamping bridge base for clamping the clamping bridge to a first substrate to be interconnected, the first substrate having solder bumps thereon;
• a lifting bridge having a lifting bridge connecting base overlying the clamping bridge base with the arms of the lifting bridge overlying the base of the clamping bridge and clamped substrate;
• a lifting rod fixedly connected to the clamping bridge connecting base and extending through an opening in the lifting bridge;
• and
• an expandable metal disposed above and in communication with the lifting bridge connecting base whereby when the device and attached first substrate is positioned on top of a second substrate to be interconnected to the first substrate, the expandable metal is adapted to exert an upward force lifting the lifting rod and a downward force on the lifting bridge connecting base raising the clamping bridge and lifting the clamped substrate relative to the second substrate to lengthen the solder interconnection.