Structures and methods for low temperature bonding using nanoparticles

A method of making an assembly, comprising:

• forming conductive nanoparticles at a surface of a first conductive element at a first surface of a substrate of a first component by exposing the first conductive element to an electrolytic bath at a current density greater than the mass transport limiting current density of the plating bath, the conductive nanoparticles having long dimensions smaller than 100 nanometers;
• juxtaposing the surface of the first conductive element with a corresponding surface of a second conductive element at a major surface of a substrate of a second component, with the conductive nanoparticles disposed in a bond region between the surfaces of the first and second conductive elements;
• and
• elevating a temperature at least at interfaces of the juxtaposed first and second conductive elements to a joining temperature at which the conductive nanoparticles cause metallurgical joints to form between the juxtaposed first and second conductive elements,
• wherein the first conductive element is one of a plurality of first conductive elements at the first surface, and the second conductive element is one of a plurality of second conductive elements at the major surface, corresponding surfaces of the first and second conductive elements being juxtaposed with one another, and
• wherein the juxtaposing step includes compressing thicknesses of the bond regions by different distances among different ones of the juxtaposed first and second conductive elements, the thickness of the bond region varying among the different ones of the juxtaposed first and second conductive elements by up to 3 microns so as to accommodate non-coplanarity of the top surfaces of at least some of the first conductive elements.