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Localization of soft tungsten contact fails with reliability implications by innovative reverse engineering techniques
Author(s) -
Touzel J.,
Neumann I.,
Lorenz H.,
Boit C.,
Körner H.,
Schurg S.
Publication year - 1996
Publication title -
quality and reliability engineering international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.913
H-Index - 62
eISSN - 1099-1638
pISSN - 0748-8017
DOI - 10.1002/(sici)1099-1638(199607)12:4<259::aid-qre36>3.0.co;2-6
Subject(s) - tungsten , reliability (semiconductor) , materials science , wafer , electrical contacts , silicon , contact resistance , reliability engineering , engineering physics , nanotechnology , nuclear engineering , computer science , forensic engineering , optoelectronics , metallurgy , engineering , power (physics) , physics , layer (electronics) , quantum mechanics
Tungsten contacts mostly fail because of a defective bottom barrier which in turn may find its origin in technological problems with contact etch, barrier or tungsten deposition. Owing to the often unstable electrical properties of those contacts, detection in electrical test or non‐destructive localization techniques is time‐consuming or even unsuccessful. The reverse engineering techniques presented here supply 100% identification and localization of the failing contacts. They reveal a disturbed region under a barrier defect produced by the aggressive chemical reaction of fluorine radicals from WF 6 deposition with silicon to the gaseous SiF 4 . The market contacts exceed the detection fails by far. Some failing contacts may slip through relaxed test conditions—the majority of them, though, still work and indicate a potential of reliability problems as could be demonstrated on chips failing the burn‐in. Thus, an analysis and classification of the contacts at the wafer level in the presented way allows an identification and first step to estimation of reliability yield risks.