Partially underfilled solder grid arrays

A method of forming an electronic device, comprising:

• providing a module comprising:
• a module substrate having a top surface and an opposite bottom surface;
• a first set of pads top surface of said module substrate and a second set of pads on said bottom surface of said module substrate, wires within said module substrate electrically connecting pads of said first set of pads to corresponding pads of said second set of pads;
• and
• a set of module solder interconnects, each solder interconnect of said set of module solder interconnects in electrical and physical contact with a corresponding pad of said second set of module pads;
• and
• forming a dielectric underfill layer on said bottom surface of said module substrate, said underfill layer in contact with regions of pads of said second set of pads not covered by solder interconnects of said set of solder interconnects and in contact with lower regions of said solder interconnects of said set of module solder interconnects, said underfill layer filling the space between said lower regions of solder interconnects of said set of solder interconnects, upper regions of solder interconnects of said set of solder interconnects extending past a top surface of said underfill layer.