| WANG Shupeng,XUE Yanpeng,FAN Lei,PAN Yingzhuo,CHENG Jie,CUI Bijia.Effects of Janus Green B Leveler on Nucleation Mechanism of Cobalt Electrodeposition in Chip Interconnection[J],53(24):178-187 |
| Effects of Janus Green B Leveler on Nucleation Mechanism of Cobalt Electrodeposition in Chip Interconnection |
| Received:January 11, 2024 Revised:March 15, 2024 |
| View Full Text View/Add Comment Download reader |
| DOI：10.16490/j.cnki.issn.1001-3660.2024.24.016 |
| KeyWord:cobalt (Co) electronic electroplating interconnection metal integrated circuit (IC) leveler thin-film technology |
| Author | Institution |
| WANG Shupeng |
School of Mechanical and Electrical Engineering, China University of Mining & Technology Beijing, Beijing , China |
| XUE Yanpeng |
National Center for Materials Service Safety, University of Science and Technology Beijing, Beijing , China |
| FAN Lei |
School of Mechanical and Electrical Engineering, China University of Mining & Technology Beijing, Beijing , China |
| PAN Yingzhuo |
School of Mechanical and Electrical Engineering, China University of Mining & Technology Beijing, Beijing , China |
| CHENG Jie |
School of Mechanical and Electrical Engineering, China University of Mining & Technology Beijing, Beijing , China |
| CUI Bijia |
School of Mechanical and Electrical Engineering, China University of Mining & Technology Beijing, Beijing , China |
|
| Hits: |
| Download times: |
| Abstract: |
| As the technology node of integrated circuit (IC) progressively shrinks, the critical dimension approaches the physical extremes of the interconnect metals. This trend is accompanied by a set of increasingly severe issues, notably the RC delay stemming from copper (Cu) interconnects. Cobalt (Co) emerges as a competitive alternative for Cu for the sub-10 nm nodes, and it is expected to replace Cu as new interconnect metal. This study explored the nucleation mechanism during the Co electronic electroplating process on a TiN surface. Janus Green B (JGB), a leveler commonly used in the Cu electroplating process, was used to improve the film quality during the Co electroplating. Multiple methods such as the electrochemical cyclic voltammetry and current transient analysis, together with the scanning electron microscopy (SEM) and X-ray diffraction (XRD) characterization were applied to fully reveal the nucleation mechanism during the Co electroplating. Cyclic voltammetry curves were used to determine the reaction composition of the system as well as the appropriate reduction potential. Transient currents were utilized to evaluate the extent of the electrode reaction, and the Volmer-Weber3D method was used to back-convolute the transient current curves to predict the form of Co reduction nucleation at the electrode surface. SEM was used to observe the microstructure of the film layer to evaluate the filling uniformity and gaplessness of the substrate. XRD was used to characterize the crystal information related to the surface of the film layer. Results showed that in the JGB-free accession system, the nucleation mode was dominated by instantaneous nucleation, supplemented by progressive nucleation. At more positive potentials, a part of progressive nucleation was slightly increased, but still dominated by instantaneous nucleation. The introduction of JGB promoted the hydrogen precipitation reaction of the system and changed the nucleation characteristics, including the size and number of nuclei, which lead to the improvement of the electrodeposition quality and the realization of higher coverage of thin film deposition. JGB with the proton together with the diffusion of the cathode surface of the combination of the electron break N==N double bond got product α. Product α and the two protons continued to occur electrode reaction to get product β and product γ. Product γ due to the unsaturated N atoms (positively charged), would be preferentially adsorbed to the tip of the cathode or the protruding place, γ molecule residual C—H—N structure could hinder the new Co atoms nucleation at the point of its adhesion, which could hinder the nucleation of new Co atoms at their attachment sites, thus enhancing the flatness of the reduced deposition on the electrode surface and making the grain growth more uniform. This uniform growth was reflected in the increase of grain size on the one hand, and on the other hand, a uniform grain structure was produced, which lead to the increase of substrate coverage and the grain boundaries were no longer obvious, and the quality of the metal electrodeposited films was improved. The adsorption of the product γ ended with the disappearance of the tip on the electrode surface. The electrode surface without added JGB remained tip-retained point active, exacerbating the inhomogeneity of the film layer. The research results are of great theoretical value for the development of a new process of ultra-smooth and defectless plating of Co interconnect metals at nodes of integrated circuits below 10 nm. |
| Close |
|
|
|