Impact of film structure on damage to low-k SiOCH film during plasma exposure

• Published in: Journal of physics. D, Applied physics Applied physics, 2009-12, Vol.42 (23), p.235201-235201 (8)
• Main Authors: Yasuhara, Shigeo, Chung, Juhyun, Tajima, Kunitoshi, Yano, Hisashi, Kadomura, Shingo, Yoshimaru, Masaki, Matsunaga, Noriaki, Samukawa, Seiji
• Format: Article
• Language: English
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Cross-disciplinary physics: materials science; rheology; Dielectric properties of solids and liquids; Dielectrics, piezoelectrics, and ferroelectrics and their properties; Exact sciences and technology; Materials science; Permittivity (dielectric function); Physics; Surface treatments
• ISSN: 0022-3727; 1361-6463
• DOI: 10.1088/0022-3727/42/23/235201

We investigated the resistance of a low-k SiOCH film structure to plasma-irradiation damage by comparing films deposited by neutral-beam enhanced chemical-vapour-deposition (NBECVD) and conventional plasma CVD techniques to clarify the degradation mechanism of the dielectric constant in low dielectric SiOCH film during plasma etching. We found that the durability of a low-k SiOCH film structure to plasma irradiation strongly depended on the kind of Si-O structure the film had. In particular, a linear Si-O structure was less affected by plasma exposure than were network/cage Si-O structures because of the small amount of stress in the O-Si-O structure. In addition, this linear Si-O structure helped to reduce the number of methyl groups removed from the film by plasma irradiation, which preserved the dielectric constant. Since the NBECVD technique can generate a low-k SiOCH film with more linear Si-O structures than conventional plasma CVD, a film made through this technique has very strong plasma durability.