US2002036100A1PendingUtilityA1

Microbeam assembly for integrated circuit interconnection to substrates

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Assignee: HONEYWELL INCPriority: Aug 26, 1999Filed: Dec 5, 2001Published: Mar 28, 2002
Est. expiryAug 26, 2019(expired)· nominal 20-yr term from priority
Inventors:John W. SlemmonsJay MessnerFrank WoolstonPatrick RedmondPierino I. ZappellaWilliam R. Fewer
Y10T29/49121Y10T29/49124Y10T29/49204Y10T29/49117H10W 72/5524H10W 72/0198H10W 72/0711H10W 72/952H10W 72/90H10W 72/9415H10W 72/07236H10W 72/252H10W 72/01204H10P 72/743H10P 72/74H10W 70/093H10W 90/701
34
PatentIndex Score
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Cited by
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References
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Claims

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.

Claims

exact text as granted — not AI-modified
That which is claimed is:  
     
         1 . A method of connecting an integrated circuit to a substrate, the method comprising the steps of: 
 attaching the integrated circuit to a plurality of conductive microbeams releasably supported by a carrier;    lifting the integrated circuit from the carrier so as to separate the microbeams from the carrier;    mounting the integrated circuit to a substrate; and    connecting the plurality of microbeams to respective ones of a plurality of substrate contacts.    
     
     
         2 . A method of connecting an integrated circuit to a substrate according to  claim 1  wherein the attaching step comprises diffusion bonding the integrated circuit to the conductive microbeams.  
     
     
         3 . A method of connecting an integrated circuit to a substrate according to  claim 2  further comprising a step of providing an integrated circuit comprising bumps for electrical connection with the conductive microbeams.  
     
     
         4 . A method of connecting an integrated circuit to a substrate according to  claim 1  wherein the attaching step comprises reflowing solder to attach the integrated circuit to the conductive microbeams.  
     
     
         5 . A method of connecting an integrated circuit to a substrate according to  claim 4  further comprising providing an integrated circuit comprising bumps for electrical connection with the conductive microbeams.  
     
     
         6 . A method of connecting an integrated circuit to a substrate according to  claim 1  wherein the attaching step comprises tape automated bonding the integrated circuit to the conductive microbeams and wherein the carrier is a TAB carrier adapted for automated conductive microbeam attachment.  
     
     
         7 . A method of connecting an integrated circuit to a substrate according to  claim 1  further comprising providing a carrier that is substantially rigid.  
     
     
         8 . A method of connecting an integrated circuit to a substrate according to  claim 1  further comprising providing a carrier comprising fan-out conductors for electrical testing of the integrated circuit.  
     
     
         9 . A method of connecting an integrated circuit to a substrate according to  claim 1  further comprising providing a carrier comprising a release layer for releasably supporting the conductive microbeams.  
     
     
         10 . A method of connecting an integrated circuit to a substrate according to  claim 9  wherein said providing step comprises providing a carrier having a release layer comprised of tungsten.  
     
     
         11 . A method of connecting an integrated circuit to a substrate according to  claim 1  further comprising providing at least one microbeam comprising a bump.  
     
     
         12 . A method of connecting an integrated circuit to a substrate according to  claim 11  wherein said providing step comprises providing a microbeam having a bump comprised of solder.  
     
     
         13 . A method of connecting an integrated circuit to a substrate according to  claim 12  wherein said providing step comprises providing a microbeam having a solder dam.  
     
     
         14 . A method of connecting an integrated circuit to a substrate according to  claim 1  further comprising providing a substrate comprising a multichip module.  
     
     
         15 . A method of connecting an integrated circuit to a substrate according to  claim 1  wherein the connecting step comprises compression bonding the microbeams to respective substrate contacts.  
     
     
         16 . A method of connecting an integrated circuit to a substrate according to  claim 1  wherein the connecting step comprises reflowing solder to connect the microbeams to respective substrate contacts.  
     
     
         17 . A method of connecting an integrated circuit to a substrate according to  claim 1  further comprising the steps of: 
 fabricating a plurality of carriers from a single carrier sheet;  
 forming a plurality of conductive microbeams on each of a plurality of carriers; and  
 dividing the carrier sheet to thereby form individual carriers prior to said attaching step.  
 
     
     
         18 . A method of forming leads for an integrated circuit having a plurality of bond pads, the method comprising the steps of: 
 releasably forming a plurality of conductive microbeams on a carrier;    bonding the plurality of bond pads to respective ones of the plurality of microbeams; and    lifting the integrated circuit from the carrier so as to separate the microbeams from the carrier, wherein the microbeams remain bonded to respective ones of the bond pads.    
     
     
         19 . A method of forming leads for an integrated circuit having a plurality of bond pads according to  claim 18  wherein the bonding step comprises diffusion bonding the bond pads to respective microbeams.  
     
     
         20 . A method of forming leads for an integrated circuit having a plurality of bond pads according to  claim 18  wherein the bonding step comprises reflowing solder to bond the bond pads to respective microbeams.  
     
     
         21 . A method of forming leads for an integrated circuit having a plurality of bond pads according to  claim 18  wherein the attaching step comprises tape automated bonding the bond pads to respective microbeams and wherein the carrier is a TAB carrier adapted for automated conductive microbeam attachment.  
     
     
         22 . A method of forming leads for an integrated circuit having a plurality of bond pads according to  claim 18  further comprising providing a carrier that is substantially rigid.  
     
     
         23 . A method of forming leads for an integrated circuit having a plurality of bond pads according to  claim 18  further comprising the steps of: 
 fabricating a plurality of carriers from a single carrier sheet; and  
 dividing the carrier sheet to thereby form individual carriers.  
 
     
     
         24 . A method of forming leads for an integrated circuit having a plurality of bond pads according to  claim 18  further comprising providing a carrier comprising a release layer for releasably supporting the conductive microbeams.  
     
     
         25 . A microbeam assembly adapted to form interconnects between integrated circuit bond pads and substrate contacts, the microbeam assembly comprising: 
 a carrier; and    a plurality of conductive microbeams releasably bonded to the carrier, wherein the conductive microbeams are sized and spaced to mate with the bond pads of an integrated circuit.    
     
     
         26 . A microbeam assembly according to  claim 25  wherein the carrier is a TAB carrier adapted for automated conductive microbeam attachment.  
     
     
         27 . A microbeam assembly according to  claim 25  wherein the carrier is substantially rigid.  
     
     
         28 . A microbeam assembly according to  claim 25  wherein the carrier comprises fan-out conductors for electrical testing of an integrated circuit.  
     
     
         29 . A microbeam assembly according to  claim 25  wherein the carrier comprises a release layer for releasably supporting the conductive microbeams.  
     
     
         30 . A microbeam assembly according to  claim 29  wherein the release layer comprises tungsten.  
     
     
         31 . A microbeam assembly according to  claim 25  wherein at least one microbeam comprises a bump.  
     
     
         32 . A microbeam assembly according to  claim 31  wherein the bump is comprised of solder.  
     
     
         33 . A microbeam assembly according to  claim 32  wherein the at least one microbeam further comprises a solder dam.  
     
     
         34 . A microbeam assembly according to  claim 31  wherein the bump is comprised of gold.  
     
     
         35 . A microbeam assembly according to  claim 31  wherein the bump is comprised of aluminum.

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