Effect of Surface Reduction Treatments of Plasma-Enhanced Atomic Layer Chemical Vapor Deposited TaN[sub x] on Adhesion with Copper

Abstract

This study performs surface reduction treatments, including hydrogen plasma treatment and rapid thermal anneal (RTA) in hydrogen ambient, to reduce the nitrogen content in the surface layer of the TaNx ultrathin film deposited by plasma-enhanced atomic layer deposition (PE-ALD). A four-point bend delamination test and a pull-off tensile test are used to study the interfacial strength of the PE-ALD thin film with copper. According to X-ray photoelectron spectroscopy and Auger electron spectroscopy, a new chemical phase with a very small nitrogen content, possibly β-TaNx , is formed on the PE-ALD TaNx thin film after the RTA treatment. The increase in the Ta/N atomic ratio in the RTA-treated TaNx thin film significantly improves the adhesion of the TaNx film with the sputter-deposited Cu layer. However, the hydrogen-plasma-treated TaNx thin film shows a slight decrease in nitrogen content but still demonstrates better adhesion with the Cu layer compared with the as-deposited one. While the Cu overlayer on the RTA-treated PE-ALD TaNx thin film can sustain the thermal anneal at 600°C , the one on the as-deposited TaNx thin film exhibits voiding even at a temperature as low as 400°C .

Coupled self-assembled monolayer for enhancement of Cu diffusion barrier and adhesion properties

“…43 The obtained interfacial toughness for C-SAM is higher than as-deposited and H 2 plasma-treated TaN x , and is even comparable to rapid thermal annealing-treated TaN x . 44 This value is sufficient to prevent delamination and cracking during CMP commercially used in the dual damascene process. 11…”

Plasma-Assisted Atomic Layer Deposition: Basics, Opportunities, and Challenges

“…In particular cases, a low-resistivity barrier and adhesion layer could also simultaneously act as a seed-layer for the electrochemical deposition process of Cu. 161,166,[180][181][182][183]220,240 Triggered by these challenges, Rossnagel and co-workers at IBM developed plasma-assisted ALD processes of Ta and Ti using the metal halides TaCl 5 and TiCl 4 as precursors and an H 2 plasma as a reducing agent. 206 As mentioned in Sec.…”

Bayesian Machine Learning for Efficient Minimization of Defects in ALD Passivation Layers

“…A two-level FFD is defined by 2 k – p , where k is the number of experimental parameters designated as factors, and p is the fraction of the factorial design (resolution III, 1/8). , To evaluate the main effects of six parameters on the etched area percentage, 1/8 fraction was used to decrease the number of experiments. Instead of a full-factorial design (2), only eight experimental runs were performed in the design of two-level FFD with resolution III (2 III 6 – 3 ). , Because of selecting a two-level design, the first-order polynomial equation was used for the linear regression model.…”

“…The surface passivation of copper is often used in corrosion protection in various applications such as microelectronics, photovoltaics, heat exchangers, gate electrodes, and interconnects. − The deposition of thin films is one of the most preferred methods for applying protective coatings. − The main challenge for depositing thin films for corrosion protection is eliminating the defects, such as pinholes and structural defects that allow the transport of reactive species in films. − Among all the available deposition techniques, atomic layer deposition (ALD) stands out owing to its high-quality thin films with excellent uniformity and conformity. ALD is also often cited for having lower defect densities. − However, the defect density on which the corrosion-protection performance depends has to be strictly controlled and minimized for wide-scale applications .…”