Microbeam assembly and associated method for integrated circuit interconnection to substrates

Abstract

A microbeam interconnection method is provided to connect integrated circuit bond pads to substrate contacts. Conductive leads (microbeams) are releasably formed, by a process such as electroplating or vacuum deposition, over a release layer deposited on a ceramic, glass or similar carrier. The microbeam material adheres only very weakly to the release layer. After the inner ends of the microbeams have been bonded to IC bond pads, such as by flip chip bump bonding, and the integrated circuit has been fully tested, the IC is lifted away from the carrier, causing the microbeams to peel away from the release layer. After straightening the microbeams against a flat surface, the outer ends of the microbeams may then be bonded to contacts on an MCM or other substrate. The method permits full electrical testing at speed and high speed bonding. The method significantly reduces mechanical stresses in interconnect bonds and thereby improves integrated circuit reliability.

1 - 35 . (Canceled).  
     
     
         36 . A method of forming interconnects between integrated circuit bond pads and microbeam conductors comprising: 
 providing a carrier having a release layer located thereon;    bonding at least one conductive microbeam to the release layer;    bonding the conductive microbeam to a bond pad of an integrated circuit; and    at least partially etching away the release layer to thereby aid in releasing the microbeam from the carrier.    
     
     
         37 . A method according to  claim 36  further comprising exerting a force on either the integrated circuit or the substrate to release the microbeam from the substrate.  
     
     
         38 . A method according to  claim 36  wherein said providing a carrier provides a carrier having a release layer formed from a material selected from the group consisting of polyimide and parylene.  
     
     
         39 . A method according to  claim 36 , wherein the release layer is on a second region of the substrate, said method further comprising bonding a conductor to a first region of the substrate.  
     
     
         40 . A method according to  claim 36 , wherein said bonding a microbeam to the release layer comprises bonding at least one microbeam having a bump to the release layer.  
     
     
         41 . A method according to  claim 40  wherein the bump is comprised of solder.  
     
     
         42 . A method according to  claim 40  wherein the bump is comprised of gold.  
     
     
         43 . A method according to  claim 40  wherein the bump is comprised of aluminum.  
     
     
         44 . A method according to  claim 36 , wherein said bonding a microbeam to the release layer comprises bonding at least one microbeam having a solder dam.  
     
     
         45 . A method according to  claim 36 , wherein the release layer comprises an oxide.  
     
     
         46 . A method according to  claim 36 , wherein the release layer comprises glass.  
     
     
         47 . A method according to  claim 39 , wherein said step of bonding a conductor to said substrate comprises bonding a conductor such that the conductor is located on a first region of the carrier and the release layer is located on a second region of the carrier, wherein said bonding a microbeam comprises bonding the conductive microbeam to the release layer such that the conductive microbeam is in electrical communication with the conductor located on the first region of substrate for electrical testing of an integrated circuit connected to the microbeam.  
     
     
         48 . A method of forming interconnects between integrated circuit bond pads and substrate contacts comprising: 
 providing a carrier having a plurality of conductors located on a first region of the carrier and a release layer located on a second region of the carrier; and    bonding a plurality of conductive microbeams to the release layer, wherein each of the microbeams is in electrical communication with at least one of the conductors.    
     
     
         49 . A method according to  claim 48 , wherein the release layer at least partially surrounds the conductors located substrate.  
     
     
         50 . A method according to  claim 48 , wherein said bonding step bonds at least one of the conductive microbeams on the release layer such that it extends at least partially onto one of the conductors.  
     
     
         51 . A method according to  claim 48  further comprising at least partially etching away the release layer to thereby aid in releasing the microbeam from the carrier.  
     
     
         52 . A method according to  claim 48  wherein the release layer is formed from a material selected from the group consisting of polyimide and parylene.  
     
     
         53 . A method according to  claim 48 , wherein the release layer comprises tungsten.  
     
     
         54 . A method according to  claim 48 , wherein the release layer comprises an oxidized metal.  
     
     
         55 . A method according to  claim 48 , wherein the release layer comprises an oxide.  
     
     
         56 . A method according to  claim 48 , wherein the release layer comprises glass.