Displacement Reactions Between Metal Ions and Nitride Barrier Layer/Silicon Substrate

Abstract

Nitride materials such as TiN and TaN have been used in the integrated circuit industry. These materials serve as the crucial barrier layer between copper and the dielectric layer, and hence should be chemically inert. However, a displacement reaction still occurs between these nitride barriers and some metal ions such as Cu 2ϩ , Ag ϩ , and Pd 2ϩ in the presence of F Ϫ . This spontaneous reaction results in the deposition of metal, and a similar reaction takes place between the metal ions and the underlying silicon substrate. Three possible mechanisms are proposed and discussed in this study. The proposed mechanisms and the details of displacement reaction were elucidated by using Auger electron spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy, nuclear magnetic resonance spectroscopy, inductively coupled plasma atomic emission spectrometer, Raman and infrared spectroscopy. TiN was found to oxidize with the formation of TiF 6 2Ϫ . Despite being regarded as a contaminant, the deposited Pd was found to be capable of serving as the platform on nitride barrier for subsequent electrodeposition of Cu.

Novel Gold Dendritic Nanoforests Combined with Titanium Nitride for Visible-Light-Enhanced Chemical Degradation

“…TiN exhibited higher electrical conductivity and optical absorption in long wavelength range than Ti [ 13 ]. Studies of depositing silver [ 14 , 15 , 16 ] or copper [ 17 ] on TiN substrates for applications have been reported. However, few studies have been published regarding gold nanostructure/TiN composite materials for applications.…”

Fabrication of potential NiMoP diffusion barrier/seed layers for Cu interconnects via electroless deposition

“…Four different wet activation processes were performed on the four lots, respectively. The four wet processes were designed to activate the insulated surface of SiO 2 for subsequent electroless deposition: (a) displacement deposition of Pd with the aid of BHF (buffered HF), 22 (b) Pd-Sn colloid commonly used as activator for electroless deposition, 23 (c) two-step pretreatment comprised of SnCl 2 /HCl sensitization and PdCl 2 /HCl activation, 24 and (d) nanoscaled Pd particles surrounded by sodium dodecyl sulfate (SDS) functional group. 25 The activation solution compositions and the procedure of the above-mentioned methods is summarized in Table I.…”

“…Thus, Pd 2ϩ ions can be reduced by accepting the electrons released from Si. Although Pd particles are successfully deposited, part of the dielectric surface must be consumed and thus the underlying Si layer is potentially exposed, which makes it very difficult to produce Pd catalyst without undesirably consuming SiO 2 due to the mechanism proposed in our previous work: 22 First step:…”

Contact-displacement PD deposition for electroless copper application

“…There are several studies showing the mechanisms of the displacement reactions between Pd ions and TiN layer [29,101]. In general, the contact displacement method was achieved through oxidizing TiN to TiF 6 2while released electrons reduced the Pd 2+ to a metallic Pd on the substrate [29,101].…”

“…Contact-displacement deposition is a process involving redox reaction [29,50,101]. Wu et al [101] proposed the chemical reaction for the contact displacement Pd deposition as follows: The presence of an hydroxyl group indicates the surface is hydrophilic, which is favorable to film deposition [107].…”