Patent ID: 7786001

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, a first transfer substrate comprising a first cavity, and a non-solder metallic core structure comprising a spherical shape, wherein said non-solder metallic core structure comprises a diameter that is less than a diameter of said first cavity; forming a first solder structure on said first electrically conductive pad; dispensing said non-solder metallic core structure into said first cavity within said first transfer substrate; first positioning after said dispensing, said first transfer substrate such that a first section of a surface of said non-solder metallic core structure is in contact with said first solder structure; first heating after said first positioning, said non-solder metallic core structure to a temperature sufficient to cause said first solder structure to melt and form a direct electrical and mechanical connection between said first section of said surface of said non-solder metallic core structure and said first electrically conductive pad; removing after said first heating, said first transfer substrate from said non-solder metallic core structure; forming a second solder structure on said second electrically conductive pad; second positioning said first substrate comprising said non-solder metallic core structure such that a second section of said surface of said non-solder metallic core structure is in contact with said second solder structure; and second heating after said second positioning, said non-solder metallic core structure to a temperature sufficient to cause said second solder structure solder to melt and form an electrical and mechanical connection between said second section of said 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.