Abstract: A method and apparatus is provided for forming an elongated solder joint between two soldered substrates of an electronic module by applying a controlled separating force between the two soldered substrates during and/or after heating of the module. The solder joints are plasticized, preferably to the molten state above the liquidus temperature, and are thereby stretched and the module is then cooled to solidify the stretched joints. An apparatus and method are provided which preferably uses a vacuum device as the separating force to stretch the existing solder joints to the desired solder height and configuration which is preferably an hour-glass shape.

Abstract: A method and apparatus are provided for forming an elongated solder joint between two soldered substrates of an electronic module or an electronic module in the process of being fabricated by using expandable solder bump means disposed between the substrates. The expandable solder bumps means comprise solder having a higher reflow temperature than the solder used to join the substrates and expansion means such as a compressed spring encased within the solder and are activated (expanded) by reflowing at a higher temperature than the melting point temperature of the solder joints.

Abstract: A device is provided for stretching solder interconnection joints between two substrates of an electronic module. The device employs an expandable metal to exert a separating (stretching) force to the two substrates whereby a lifting rod attached to a clamping bridge is cause to move upwards by expansion of the expandable metal raising a first substrate clamped thereto. A lifting bridge in connection with the clamping bridge is caused to move downward to maintain the lifting bridge in contact with the second substrate being interconnected to the first substrate.