Comparison of characteristics and integration of copper diffusion-barrier dielectrics T.C. Wang a , Y.L. Cheng b , Y.L. Wang b, * , T.E. Hsieh a , G.J. Hwang a , C.F. Chen a a Department of Materials Science and Engineering, National Chiao-Tung University, Hsin-Chu, Taiwan b College of Science and Engineering, National University of Tainan, Taiwan Available online 11 August 2005 Abstract The characteristics of various copper (Cu) barrier layers, including SiN, SiCN, and SiCO, were investigated in this work. Carbon-based barrier films (SiCN and SiCO) improved the dielectric constant and line-to-line capacitance, but led to sacrifice in film deposition rate, diffusion-barrier performance, and adhesion strength to Cu in comparison with SiN films. In addition, SiN and SiCO films showed the superior electromigration (EM) performance and stress-induced void migration (SM) performance, respectively. Furthermore, the reliability results of SM and EM are strongly related to the barrier film stress characteristics and the adhesion strength between Cu layers. Therefore, optimization of the barrier layer stress and the enhancement of the interfacial condition between Cu and barrier films are crucial to significantly improve reliability. D 2005 Elsevier B.V. All rights reserved. Keywords: Barrier layer; Low dielectric constant; Adhesion strength; Capacitance 1. Introduction The interconnect resistance–capacitance (RC) delay is a dominant factor in determining the performance of ultra large-scale integrated circuits as minimum device shrinks below 180 nm. Although many low-k (k < 3) materials has been used as interlayer dielectrics (ILD), high dielectric constant (k =7 ¨ 8) of silicon nitride (SiN) film is still the primary candidate for the Cu cap barrier and etch stop layer (ESL) required in the Cu damascene process [1–3]. Thus, this increases the effective k value of stack dielectric films, and limits the reduction of the RC delay in ultra large-scale integration [4,5]. As a result, amorphous silicon carbide (SiC), amorphous silicon nitricarbide (SiCN), and amor- phous silicon oxycarbide (SiCO) deposited using a plasma- enhanced chemical vapor deposition (PECVD) system have received much attention for applications as Cu cap barrier and ESL in Cu damascene process [6–9]. The intrinsic properties of carbon-doped barrier films (SiCN and SiCO) have been extensively investigated by many researchers [10–12]. However, very few papers have studied the integration and reliability of barrier dielectrics in the Cu dual damascene process [13,14]. In this work, we investigated the physical properties, thermal stability, and integrated electrical performance for SiN, SiCN and SiCO dielectric barrier films. Furthermore, reliability results of electromigration (EM) and stress- induced voiding migration (SM) related to the deposited film’s properties were also studied. 2. Experiment All thin film deposition was performed on an Applied Materials Producer system with a 200 mm DxZ chamber. The thin film was deposited on a p -type (100) silicon substrate by using radio frequency (13.56 MHz) PECVD. A gas mixture of trimethylsilane (3MS) and helium (He) were employed with either NH 3 or CO 2 , which were used to deposit SiCN or SiCO films, respectively. The detailed process conditions for different Cu barrier dielectrics are listed in Table 1. 0040-6090/$ - see front matter D 2005 Elsevier B.V. All rights reserved. doi:10.1016/j.tsf.2005.07.059 * Corresponding author. Tel.: +886 6 505 9688; fax: +886 6 5051262. E-mail address: ylwang@tsmc.com (Y.L. Wang). Thin Solid Films 498 (2006) 36 – 42 www.elsevier.com/locate/tsf