Methods of making connections to a microelectronic unit

Abstract

A component for mounting semiconductor chips or other microelectronic units includes a flexible top sheet with an array of terminals on it, and with flexible leads extending downwardly from the terminals. A compliant dielectric support layer surrounds the leads, holding the lead tips in precise locations. The leads are desirably formed from wire such as gold wire, and have eutectic bonding alloy on their tips. The component can be laminated to a chip or other unit under heat and pressure to form a complete subassembly with no need for individual bonding to the contacts of the chip. The subassembly can be tested readily and provides compensation for thermal expansion.

What is claimed is:  
     
         1 . A component for forming connections to a microelectronic unit comprising: 
 (a) a flexible dielectric top sheet;    (b) a plurality of electrically conductive terminals mounted on said top sheet;    (c) a support layer underneath said top sheet, said support layer having a bottom surface remote from said top sheet; and    (d) a plurality of flexible, electrically conductive, elongated leads connected to said terminals and extending side-by-side downwardly from said terminals through said support layer, each said lead having a lower end adjacent the bottom surface of said support layer, said lower ends of said leads being adapted to bond to contacts on a microelectronic unit when the component is engaged with a unit under predetermined temperature and pressure conditions, and thereby electrically connect said terminals with the contacts on the surface, said support layer surrounding and supporting said leads.