Broadband UV-assisted thermal annealing of low-k silicon carbonitride films using a C-rich silazane precursor

Wei Yuan Chang, Hau Ting Chung, Yi Chang Chen, Jih-Perng Leu*

*Corresponding author for this work

Research output: Contribution to journalLetterpeer-review

7 Scopus citations


Low-k dielectric silicon carbonitride (SiCxNy) films are deposited by plasma-enhanced chemical vapor deposition using a carbon-rich silazane precursor, N-methyl-aza-2,2,4-trimethylsilacyclopentane (SiC7NH17), at 100 °C. The post-treatments of SiCxNy films are carried out by thermal annealing and a broadband UV-assisted thermal annealing (UV-annealing) at 400 °C for 5 min. Compared to the thermal annealing treatment, UV-annealing can improve both dielectric and mechanical properties of low-k SiCxNy films. Under thermal annealing, SiCxNy films show great thermal stability, but little structural change. In contrast, upon UV-annealing, most of the Si-H and N-H bonds are broken up, which induces more Si-N cross-linking and converts Si-C matrix into Si-N matrix. The ethylene bridges in Si-(CH2)2-Si also remain intact, but the unbridged hydrocarbons in Si-(CH2)2-N and Si-CH2-CH3 bonds decompose completely during the UV-annealing process. These account for the reduced dielectric constant to k = 3.2 from 3.6 and a 21% enhancement of Young's modulus to 7.4 GPa in the SiCxNy films after UV-annealing. Broadband UV-annealing shows promise as a post-treatment method for enhancing the properties of low-k dielectric barrier, SiCxNy films.

Original languageEnglish
Article number060601
JournalJournal of Vacuum Science and Technology B: Nanotechnology and Microelectronics
Issue number6
StatePublished - 1 Nov 2018


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