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Using a Barrier Layer to Inhibit Ti/Oxide Reaction to Reduce RC Delay and Improve Electromigration in Al-Cu/Ti/W Interconnect for High Power Analog and Mixed Signal Applications

Published online by Cambridge University Press:  01 February 2011

William Murphy ,
Tom C Lee ,
Jonathan Chapple-Sokol ,
Daniel A Delibac ,
Z. X. He ,
Stephen E Luce ,
Stephen A Mongeon ,
David C Thomas ,
Daniel S Vanslette  and
Timothy D Sullivan
William Murphy
Affiliation:
murphw@us.ibm.com, International Business Machines, AZQv, 1000 River Road, Bldg 975C, Essex Junction, VT, 05452, United States, 802-288-3477, 802-769-9452
Tom C Lee
Affiliation:
tomlee@us.ibm.com, International Business Machines, 1000 River Road, Essex Junction, VT, 05452, United States
Jonathan Chapple-Sokol
Affiliation:
chapple@us.ibm.com, International Business Machines, 1000 River Road, Essex Junction, VT, 05452, United States
Daniel A Delibac
Affiliation:
ddelibac@us.ibm.com, International Business Machines, 1000 River Road, Essex Junction, VT, 05452, United States
Z. X. He
Affiliation:
johnhe@us.ibm.com, International Business Machines, 1000 River Road, Essex Junction, VT, 05452, United States
Stephen E Luce
Affiliation:
sluce@us.ibm.com, International Business Machines, 1000 River Road, Essex Junction, VT, 05452, United States
Stephen A Mongeon
Affiliation:
smongeon@us.ibm.com, International Business Machines, 1000 River Road, Essex Junction, VT, 05452, United States
David C Thomas
Affiliation:
dcthomas@us.ibm.com, International Business Machines, 1000 River Road, Essex Junction, VT, 05452, United States
Daniel S Vanslette
Affiliation:
vansletd@us.ibm.com, International Business Machines, 1000 River Road, Essex Junction, VT, 05452, United States
Timothy D Sullivan
Affiliation:
tdsulliv@us.ibm.com, International Business Machines, 1000 River Road, Essex Junction, VT, 05452, United States
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Abstract

In this paper, we report a novel method to improve aluminum interconnect electromigration performance, reduce metal line sheet resistance (Rs) and reduce via contact resistance (Rc) in a minimum pitch design. We report the effects of bottom redundancy layers on electrical line and via resistance and upstream electromigration performance. We studied 4 metallization stacks: (I) Ti/TiN/AlCu/Ti/TiN, (II) Ti/TiN/Ti/AlCu/Ti/TiN (annealed at 400°C for 20 minutes), (III) a flash process/stack I, (IV) stack III with aluminum deposition temperature of 250°C. Aluminum deposition temperature in stacks I, II, and III are 200°C. Bottom Ti/TiN, AlCu, and Top Ti/TiN layers have the same thickness for all these stacks. Metal line Rs and via contact resistances (Rc) of stack IV are 5% and 10% lower, respectively, than stack I. Stack II metal line sheet resistance is 15% higher than stack I, which is attributed to Al consumption in the TiAl3 formation during 400°C/20minutes annealing. Electromigration performance is best with stack IV followed by III, II, then I.

Keywords

electromigrationmetallic conductorbarrier layer
Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 1079: Symposium N – Materials and Processes for Advanced Interconnects for Microelectronics , 2008 , 1079-N09-01
Copyright
Copyright © Materials Research Society 2008

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References

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