Interposer with microspring contacts and methods of making and using same

An interposer for connecting a first electronic structure having bonding pads disposed at a first pitch on a first surface thereof to a second electronic structure having bonding pads disposed at a second pitch on a first surface thereof, said first and second electronic structures and said interposer disposed in a stacked arrangement, comprising:

• said interposer disposed over said first electronic structure, said interposer comprising:
• a dielectric body having a first surface and a second surface, a plurality of microsprings, each microspring comprising:
• an anchor portion and a free portion in physical and electrical communication with one another;
• said free portion having a non-planar profile, in the absence of an external force applied thereto, said free portion being free to move relative to said first surface of said dielectric body;
• said anchor portion being fixed to said dielectric body and disposed for electrical connection thereto at said second surface of said dielectric body;
• and
• at least a portion of each said microspring between its anchor portion and its free portion being disposed within said dielectric body;
• electrical interconnection between said bonding pads of said first electronic structure and said anchor portions of said microsprings at said second surface of said dielectric body;
• said second electronic structure disposed over said first surface of said dielectric body such that said bonding pads of said second electronic structure are physically and electronically connected to said free portions of said microsprings;
• and
• whereby selected ones of said bonding pads of said first electronic structure are uniquely electronically connected to selected ones of said bonding pads of said second electronic structure by way of said microsprings.

A method of manufacturing an interposer, comprising:

• forming a microspring over a substrate, said substrate having a first surface and a second surface substantially parallel to but opposite said first surface;
• releasing a free portion of said microspring such that said free portion assumes a non-planar profile, in the absence of an external force applied thereto, and is free to deflect over said substrate;
• forming a laminate structure over said substrate such that said microspring is at least partially embedded within said laminate structure;
• and
• processing said substrate such that an anchor portion of said microspring secured thereto is exposed for electrical contact at said second surface of said substrate.

A method of connecting a first electronic structure having bonding pads disposed at a first pitch on a first surface thereof to a second electronic structure having bonding pads disposed at a second pitch on a first surface thereof, using an interposer, said first and second electronic structures and said interposer disposed in a stacked arrangement, comprising:

• disposing said interposer over said first electronic structure, said interposer comprising:
• a dielectric body having a first surface and a second surface, a plurality of microsprings, each microspring comprising:
• an anchor portion and a free portion in physical and electrical communication with one another;
• said free portion having a non-planar profile, in the absence of an external force applied thereto, said free portion being free to move relative to said first surface of said dielectric body;
• said anchor portion being fixed to said dielectric body and disposed for electrical connection thereto at said second surface of said dielectric body;
• and
• at least a portion of each said microspring between its anchor portion and its free portion being disposed within said dielectric body;
• electrically interconnecting said bonding pads of said first electronic structure to said anchor portions of said microsprings at said second surface of said dielectric body;
• disposing said second electronic structure over said first surface of said dielectric body such that said bonding pads of said second electronic structure are physically and electronically connected to said free portions of said microsprings;
• and
• whereby selected ones of said bonding pads of said first electronic structure are uniquely electronically connected to selected ones of said bonding pads of said second electronic structure by way of said microsprings.