Electromigration behavior of hot-sputtered Al(Cu) versus chemical vapor deposition W vias
作者:
R. G. Filippi,
E. N. Levine,
K. P. Rodbell,
期刊:
Journal of Vacuum Science&Technology B: Microelectronics and Nanometer Structures Processing, Measurement, and Phenomena
(AIP Available online 1997)
卷期:
Volume 15,
issue 3
页码: 750-756
ISSN:1071-1023
年代: 1997
DOI:10.1116/1.589381
出版商: American Vacuum Society
关键词: W
数据来源: AIP
摘要:
The electromigration behavior of hot-sputtered aluminum-copper (Al-Cu) vias is compared to that of chemical vapor deposition (CVD) tungsten (W) vias. Al(Cu) vias were prepared by one of two processes: (1) the via was filled and then defined by chemical mechanical polish (CMP) and (2) the via and top metal line were deposited in the same step (this is referred to as the “Sprint” process). During electromigration testing, the W via chains exhibited more uniform resistance changes with time than the CMP Al(Cu) via chains. This had a direct impact on the shape parameter of the log-normal lifetime distribution, whereσwas higher for the CMP Al(Cu) via chains. A closer examination of the failure distributions revealed the need to describe the CMP Al(Cu) via lifetimes by a three-parameter log-normal distribution as opposed to the conventional two-parameter log-normal distribution. Failure analysis of the CMP Al(Cu) samples indicated electromigration failures downstream from the via in the direction of the electron flow. Samples prepared by the Sprint process showed>5× electromigration lifetime improvement as compared to either the CVD W or CMP Al(Cu) via samples.
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