Effects of He (90%)/H{sub 2} (10%) plasma treatment on electric properties of low dielectric constant SiCOH films

• Published in: Materials research bulletin Vol. 47; no. 10
• Main Authors: Kim, Hoonbae, Ha, Myung Hoon, Jung, Donggeun, Chae, Heeyeop, Kim, Hyoungsub
• Format: Journal Article
• Language: English
• Published: United States 15.10.2012
• Subjects: DEPOSITION; ELECTRIC POTENTIAL; LEAKAGE CURRENT; MATERIALS SCIENCE; MICROELECTRONICS; PEAKS; PERMITTIVITY; PLASMA; THIN FILMS; X-RAY PHOTOELECTRON SPECTROSCOPY
• ISSN: 0025-5408; 1873-4227
• DOI: 10.1016/J.MATERRESBULL.2012.04.097

In microelectronics industry, integration of the low dielectric constant (low-k) material films is a continuing issue due to the decreasing device feature size. To improve electric properties, various post-deposition treatments of the low-k material films can be used. In this work, we used room temperature treatment of He/H{sub 2} plasma and investigated the effects of plasma treatment on the electrical properties of low-k SiOCH films. Plasma treatment time changed from 300 to 1800 s. After treatment, the dielectric constant was decreased from 2.9 to 2.48, and the thickness of the low-k SiCOH films changed by only ∼5%. The leakage current densities of the low-k SiCOH films were decreased to ∼10{sup −11} A/cm{sup 2}, with treatment time ≥600 s. The breakdown occurred only around 2 V for films plasma-treated for 600 and 900 s. However, for 1800 s treatment time, the breakdown voltage was enhanced dramatically and breakdown occurred at applied voltage higher than 40 V. The surface composition change of the films after treatment was investigated by X-ray photoelectron spectroscopy (XPS). As the plasma treatment time was increased, the intensities of C-C/C-H and C-Si peaks were decreased while the intensities of Si-O and C-O peaks were increased. It is thought that increase of oxygen content of the SiCOH film, after plasma treatment, contributed to leakage current reduction and breakdown voltage increase.