Patent ID: 8541291

Claim:
A method for forming an electrical structure comprising: providing a first substrate comprising a first electrically conductive pad, a second substrate comprising a second electrically conductive pad, and a transfer structure, wherein said transfer structure comprises a sacrificial carrier substrate, a polymer release layer formed over and in contact with said sacrificial carrier substrate, and a non-solder metallic core structure formed over and in contact with said polymer release layer, and wherein said non-solder metallic core structure comprises a cylindrical shape; positioning said transfer structure such that a first surface of said non-solder metallic core structure is in contact with said first electrically conductive pad; thermo-compression bonding said first surface of said non-solder metallic core structure to said first electrically conductive pad; removing said polymer release layer from said non-solder metallic core structure; removing and said sacrificial carrier substrate from said polymer release layer; forming a first solder structure on said second electrically conductive pad; positioning said first substrate comprising said non-solder metallic core structure such that a second surface of said non-solder metallic core structure is in contact with said first solder structure; and heating said first solder structure to a temperature sufficient to cause said first solder structure to melt and form an electrical and mechanical connection between said second surface of said non-solder metallic core structure and said second electrically conductive pad resulting in an electrical and mechanical connection between said first electrically conductive pad and said second electrically conductive pad.