AVS 50th International Symposium
    Thin Films Wednesday Sessions
       Session TF-WeP

Paper TF-WeP6
Characterization of PECVD Low-k Films by Positronium-Annihilation Lifetime Spectroscopy

Wednesday, November 5, 2003, 11:00 am, Room Hall A-C

Session: Poster Session
Presenter: T. Ohdaira, National Institute of Advanced Industrial Science and Technology (AIST), Japan
Authors: T. Ohdaira, National Institute of Advanced Industrial Science and Technology (AIST), Japan
R. Suzuki, National Institute of Advanced Industrial Science and Technology (AIST), Japan
Y. Shioya, Semiconductor Process Laboratory (SPL), Japan
K. Maeda, Semiconductor Process Laboratory (SPL), Japan
Correspondent: Click to Email
Positronium-annihilation lifetime spectroscopy (PALS) was used to measure pore size distributions in porous SiOCH films for low-k interlayer dielectrics and Cu-diffusion barriers, which were grown by plasma-enhanced chemical vapor deposition (PECVD) with source gases of HMDSO (hexamethyldisiloxane). In the PECVD, the dielectric constants (k) of the films change with the deposition conditions (pressure, flow rate, RF power, temperature, etc). The PALS analysis showed that the PECVD-grown SiOCH films with k in the range from 2.6 to 4 contain pores with average sizes from 0.4 to 1.2 nm, and that the k values of the films correlate strongly with the pore sizes. The PALS depth profiling was also carried out for the SiOCH low-k films with post plasma treatments and UV irradiations. For the plasma treated films, it is found that the size of the pores in a few 10 nm beneath the surface decreases significantly, indicating that a thin dense layer is formed on the surface.