Reliability challenges for copper interconnects

被引:217
作者
Li, BZ [1 ]
Sullivan, TD [1 ]
Lee, TC [1 ]
Badami, D [1 ]
机构
[1] IBM Microelect, Semicond Technol Reliabil, Essex Jct, VT 05452 USA
关键词
D O I
10.1016/j.microrel.2003.11.004
中图分类号
TM [电工技术]; TN [电子技术、通信技术];
学科分类号
0808 ; 0809 ;
摘要
In the past few years, copper has been widely used as interconnect metallization for advanced ultralarge-scale integration (ULSI) circuits. Due to the unique chemical properties of copper compared to its predecessor, aluminum, different integration processes must be used for circuit fabrication, that is, the damascene versus reactive ion etch (RIE) process. This difference in integration processes introduces a series of reliability concerns for copper interconnects. After a brief comparison of copper and aluminum interconnects, this article discusses the impact of the differences in the material properties and integration process on reliability. Details are provided on two advanced metallization reliability failure mechanisms: electromigration and stress migration. For copper interconnects, the interface between the cap and the copper metal serves as the fast diffusion path. To improve copper interconnect reliability, development efforts have focused on suppressing copper or copper vacancy diffusion along the interface. Two copper interfaces, the copper/cap interface and the copper/liner (or diffusion barrier) interface, are critical for copper reliability. For commonly used liners, such as Ta/TaN, the copper/liner interface is relatively easy to control compared to the copper/cap interface. For dual-damascene copper lines, a copper via is used to connect the lower level to the upper level. Unlike the robust tungsten stud used in aluminum interconnects, the copper via has been identified as a weak link in dual-damascene copper connections; the majority of early reliability failures can be attributed to the copper vias. The three most critical process factors and elements affecting copper interconnect reliability are copper vias and interfaces and the liner coverage. Using a low-k dielectric with a copper interconnect introduces several new challenges to reliability, including dielectric breakdown, temperature cycle, and stability within packages. Extensive knowledge is urgently needed to understand these issues. (C) 2003 Elsevier Ltd. All rights reserved.
引用
收藏
页码:365 / 380
页数:16
相关论文
共 47 条
  • [21] TDDB and voltage-ramp reliability of SiC-base dielectric diffusion barriers in Cu/low-k interconnects
    Jow, K
    Alers, GB
    Sanganeria, M
    Harm, G
    Fu, H
    Tang, X
    Kooi, G
    Ray, GW
    Danek, M
    [J]. 41ST ANNUAL PROCEEDINGS: INTERNATIONAL RELIABILITY PHYSICS SYMPOSIUM, 2003, : 598 - 599
  • [22] Diffusion barrier properties of transition metal thin films grown by plasma-enhanced atomic-layer deposition
    Kim, H
    Cabral, C
    Lavoie, C
    Rossnagel, SM
    [J]. JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B, 2002, 20 (04): : 1321 - 1326
  • [24] Relationship between interfacial adhesion and electromigration in Cu metallization
    Lane, MW
    Liniger, EG
    Lloyd, JR
    [J]. JOURNAL OF APPLIED PHYSICS, 2003, 93 (03) : 1417 - 1421
  • [25] Electromigration threshold for Cu/low k interconnects
    Lee, KD
    Ogawa, ET
    Yoon, S
    Lu, X
    Ho, PS
    [J]. PROCEEDINGS OF THE IEEE 2003 INTERNATIONAL INTERCONNECT TECHNOLOGY CONFERENCE, 2003, : 259 - 261
  • [26] Line depletion electromigration characteristics of Cu interconnects
    Li, BZ
    Sullivan, TD
    Lee, TC
    [J]. 41ST ANNUAL PROCEEDINGS: INTERNATIONAL RELIABILITY PHYSICS SYMPOSIUM, 2003, : 140 - 145
  • [27] Effect of liner thickness on electromigration lifetime
    Liniger, EG
    Hu, CK
    Gignac, LM
    Simon, A
    [J]. JOURNAL OF APPLIED PHYSICS, 2003, 93 (12) : 9576 - 9582
  • [28] ELECTROMIGRATION IN COPPER CONDUCTORS
    LLOYD, JR
    CLEMENT, JJ
    [J]. THIN SOLID FILMS, 1995, 262 (1-2) : 135 - 141
  • [29] LLOYD JR, 1999, J PHYS D, V32, pR110
  • [30] LLOYD JR, 2002, 2002 INT INT REL WOR