Browse Prior Art Database

Cu(Sn) Alloys for Chip and Package Interconnects

IP.com Disclosure Number: IPCOM000113785D
Original Publication Date: 1994-Oct-01
Included in the Prior Art Database: 2005-Mar-27
Document File: 2 page(s) / 41K

Publishing Venue

IBM

Related People

Hu, CK: AUTHOR [+5]

Abstract

Copper metallizations are often used for semiconductor chips and packages in which the copper films are used as both a solderable material, and a conductor in mutilayer copper-clad Invar board or copper-polymide for ULSI packaging. Cu is also a material of high potential for on-chip interconnection metallization due to its better conductivity than Al(Cu). As devices are continually scaled down to submicron dimensions, the electromigration reliability becomes increasingly important due to the shrinkage of conducting area.

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Cu(Sn) Alloys for Chip and Package Interconnects

      Copper metallizations are often used for semiconductor chips
and packages in which the copper films are used as both a solderable
material, and a conductor in mutilayer copper-clad Invar board or
copper-polymide for ULSI packaging.  Cu is also a material of high
potential for on-chip interconnection metallization due to its better
conductivity than Al(Cu).  As devices are continually scaled down to
submicron dimensions, the electromigration reliability becomes
increasingly important due to the shrinkage of conducting area.

      The electromigration in the pure sputtered Cu, and Al(2%Cu)
have been reported [1,2].  It showed that the mass transport rates in
pure Cu are much slower than that in Al in Al(2% Cu) at temperature
above 200ºC.  However, the advantage of electromigration
resistance in Cu at actual chip operation temperature was lost due to
the smaller electromigration activation of pure Cu (0.61 eV) than
Al(Cu) (0.88 eV).  The measurements of electromigration in Cu(0.5 to
2 Sn) alloys shows that the additional Sn impurities in Cu greatly
reduce the electromigration damage in Cu.  The Sn impurities less
than 4 wt.% in Cu can be prepared by using one or combination of
layers
diffusion, physical, chemical, ion implant, and plating techniques.
  References
  (1) C. K. Hu, P. S. Ho, M. B. Small and K. Kelleher,
      "Electromigration in Al/W and Al(Cu)/W Interconnect
       Structures,"...