Thermal stability of trimethylsilylated mesoporous silica thin films as the ultralow-k dielectric for copper interconnects

J. Y. Chen, Fu-Ming Pan*, Li Chang, A. T. Cho, K. J. Chao

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

11 Scopus citations


Surfactant templated mesoporous silica thin films were prepared as the intermetal dielectric for ultralarge scaled integrated circuit application, and the thermal and chemical stability of the Cunitrided Tamesoporous silica film stack on the Si wafer was studied. Trimethylsilylation of the mesoporous silica thin film by hexamethyldisilazane vapor treatment significantly improves hydrophobicity of the mesoporous dielectric, and a dielectric constant (k) smaller than 2 can be obtained for the thin film. According to Fourier transform infrared spectroscopy and thermal desorption spectroscopy, decomposition of trimethylsilyl groups on the pore surface becomes significant at temperatures larger than 400 °C. However, when the metallized film stack was annealed at temperatures higher than 400 °C, the film stack shows little delamination between layers and still retains smooth interfaces according to Auger electron spectroscopy and transmission electron microscopy analyses. Ta2 C nanoparticles were found to exist at the Ta (N) mesoporous silica interface of the film stack annealed at 600 °C. Bias-temperature stress test of the metallized film stack shows little Cu diffusion into the mesoporous dielectric layer.

Original languageEnglish
Pages (from-to)2034-2040
Number of pages7
JournalJournal of Vacuum Science and Technology B: Microelectronics and Nanometer Structures
Issue number5
StatePublished - Sep 2005

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