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Process And Structure for Improved Electromigration Resistance

IP.com Disclosure Number: IPCOM000100162D
Original Publication Date: 1990-Mar-01
Included in the Prior Art Database: 2005-Mar-15
Document File: 2 page(s) / 50K

Publishing Venue

IBM

Related People

Cook, HC: AUTHOR [+2]

Abstract

An aluminum-copper (Al-Cu) line is contained in a trough of titanium/ tungsten (Ti/W) to create a low resistivity line having improved electromigration resistance, especially at line to stud interconnections.

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This is the abbreviated version, containing approximately 99% of the total text.

Process And Structure for Improved Electromigration Resistance

       An aluminum-copper (Al-Cu) line is contained in a trough
of titanium/ tungsten (Ti/W) to create a low resistivity line having
improved electromigration resistance, especially at line to stud
interconnections.

      Referring to Fig. 1, planarized W studs 10 and 12 in insulator
14 are first coated with insulating layer 16. Layer 16 is then
patterned and etched to form cavities where a next level of metal
lines is to be formed.

      Referring to Fig. 2, Ti followed by W is sputtered to form
layer 18.  Next, Al-Cu 20 is sputter deposited to a thickness
exceeding that of insulator 16.  A planarizing process is then used
to remove all conductive material, layers 18 and 20, from upper
surfaces of insulator 16. Another insulating layer 22 may be
deposited, patterned, etched, and holes filled to form studs 24 and
26 which connect to the lines comprised of Al-Cu 20 in troughs of TiW
18.

      Thus, an electrical current path exists through highly
electromigration resistant Ti/W from a low resistivity Al-Cu line
along the line length and to a W stud above or below the line.

      It is preferable to make several, parallel narrow conductive
lines rather than single, wide lines when the planarizing process is
a polishing method tending to remove the softer Al-Cu at a faster
rate than the harder Ti/W and insulator materials.  Better
planarization, less "dishing", is achieved by this means....