Ultraviolet irradiation effect on the properties of leakage current and dielectric breakdown of low-dielectric-constant SiOC(\H) films using comb capacitor structure Chang Young Kim a , R. Navamathavan b , Heang Seuk Lee a , Jong-Kwan Woo a , Myung Taek Hyun c , Kwang-Man Lee d , Won Young Jeung e , Chi Kyu Choi a, ⁎ a Nano Thin Film Materials Laboratory, Department of Physics, Jeju National University, Ara 1 Dong, Jeju 690-756, Republic of Korea b Semiconductor Materials Process Laboratory, School of Advanced Materials Engineering, Chonbuk National University, Chonju 561-756, Republic of Korea c Department of Mechanical Engineering, Jeju National University, Ara 1 Dong, Jeju 690-756, Republic of Korea d Department of Electronic Engineering, Cheju National University, Ara 1 Dong, Jeju 690-756, Republic of Korea e Advanced Materials Division, Korean Institute of Science and Technology, Seoul 130-650, Republic of Korea abstract article info Available online 22 April 2011 Keywords: Low-k materials SiOC(\H) film PECVD UV irradiation FTIR Low-dielectric constant SiOC(\H) films were deposited on p-type Si(100) substrates by plasma-enhanced chemical-vapor deposition (PECVD) using dimethyldimethoxy silane (DMDMS, C 4 H 12 O 2 Si) and oxygen gas as precursors. To improve the physicochemical properties of the SiOC(\H) films, the deposited SiOC(\H) films were exposed to ultraviolet (UV) irradiation in a vacuum. The bonding structure of the SiOC(\H) films was investigated by Fourier transform infrared (FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS). The electrical characterization of SiOC(\H) films were carried out through I–V measurements using the comb-like patterns of the TiN/Al/Ti/SiOC(\H)/TiN/Al/Ti metal–insulator–metal (MIM) structure. Excessive UV treatment adversely affected the SiOC(\H) film, which resulted in an increased dielectric constant. Our results provide insight into the UV irradiation of low-k SiOC(\H) films. © 2011 Elsevier B.V. All rights reserved. 1. Introduction Next generation microelectronic interconnects require the use of dielectric thin films with continuously decreasing permittivity to overcome limitations induced by parasitic crosstalk and signal delay [1–3]. To address these issues, low resistivity Cu metallization and low dielectric constant materials are being used to replace conventional Al/SiO 2 interconnect structures [4–6]. Carbon-doped silicon oxide (SiOCH) thin films deposited using plasma-enhanced chemical vapor deposition (PECVD) are being used in interconnect applications. However, to successfully integrate these thin films into complex device structures is challenging due to their lack of mechanical strength. Significant efforts are being made toward improving their mechanical properties using post-deposition curing treatments with external energy sources such as thermal, plasma, e-beam, and ultraviolet (UV) radiation [3,7–9]. UV treatment can improve structural quality by initiating a cross-linking reaction with Si\O\Si bonds in SiOC(\H) films. The mechanism of the molecular rearrange- ment by exposure to UV irradiation and the resulting structural configuration will vary depending on the energy of the UV light source. The rearrangement process is much stronger for highly- energetic photons with energies above 6.5 eV (wavelength below 190 nm) due to, the threshold energy required to break the Si\CH 3 bond [10]. UV irradiation promotes cross-linking of the chain and reorganizes the Si\O\Si skeleton toward a more stable network structure. We studied the impact of UV irradiation in SiOC(\H) low dielectric thin films. Detailed structural, chemical, mechanical, and electrical characterizations of the SiOC(\H) films prepared with and without UV treatment were investigated. 2. Experimental details SiOC(\H) thin films were deposited on p-Si(100) substrates by using a mixture of DMDMS (C 4 H 12 O 2 Si) precursor and oxygen gas in a plasma-enhanced chemical-vapor deposition (PECVD) system. The plasma was generated using a radio frequency (rf) power supply with a frequency of 13.56 MHz between the two electrodes, and the working pressure was fixed at 100 mTorr. The films were deposited at room temperature with 600 W rf power. The total flow rate of the precursors was maintained at 40 sccm, and flow rate ratio of R(%) = [DMDMS / (O 2 + DMDMS)] × 100 was fixed at 80%. UV treatments of deposited SiOC(\H) films were carried out at 400 °C in a vacuum environment. To prevent recondensation of the DMDMS precursor, Thin Solid Films 519 (2011) 6732–6736 ⁎ Corresponding author. Tel.: + 82 64 754 3512; fax: + 82 64 756 3506. E-mail address: cckyu@jejunu.ac.kr (C.K. Choi). 0040-6090/$ – see front matter © 2011 Elsevier B.V. All rights reserved. doi:10.1016/j.tsf.2011.04.058 Contents lists available at ScienceDirect Thin Solid Films journal homepage: www.elsevier.com/locate/tsf