Patent ID: 8541299
Filing Date: 2013-09-24
Classification: H01L,H05K,Y02P,Y10T

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