Sacrificial CVD film etch-back process for air-gap Cu interconnects

• Published in: Thin solid films Vol. 515; no. 12; pp. 4960 - 4965
• Main Authors: Uno, Shoichi, Katsuyama, Kiyomi, Noguchi, Junji, Sato, Kiyohiko, Oshima, Takayuki, Katsuyama, Masanori, Hara, Kazusato
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Lausanne Elsevier B.V 23.04.2007; Elsevier Science
• Subjects: Air-gap; Chemical vapor deposition (including plasma-enhanced cvd, mocvd, etc.); Cross-disciplinary physics: materials science; rheology; Cu interconnect; Etching and cleaning; Exact sciences and technology; Low-k; Materials science; Methods of deposition of films and coatings; film growth and epitaxy; Other semiconductors; Physics; Physics of gases, plasmas and electric discharges; Physics of plasmas and electric discharges; Plasma applications; Plasma treatment; Specific materials; Cu interconnect; Low-k; Plasma treatment; Air-gap; Plasma assisted processing; Photoelectron spectroscopy; III-V compound; Thin films; CVD; Gallium phosphides; Plasma etching; Transition elements; Stress effects; Copper; Reliability; Permittivity; Electrical characteristic; III-V semiconductors
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/j.tsf.2006.10.068

A novel sacrificial chemical vapor deposition film etch-back process for Cu air-gap interconnects was developed. The etched-back Cu surfaces were analyzed by X-ray photoelectron spectroscopy. The electrical characteristics and the stress induced voiding reliability were evaluated. The CF 4 etch-back process was found not to degrade interconnect reliability. A four-level dual damascene Cu interconnect structure was successfully fabricated, and its effective dielectric constant was 2.8, 32% lower than that of a conventionally fabricated one. In situ N 2 or Ar plasma treatments after etch-back were investigated to reduce the Cu degradation.