1
|
Santos RF, Oliveira BMC, Chícharo A, Alpuim P, Ferreira PJ, Simões S, Viana F, Vieira MF. Seedless Cu Electroplating on Co-W Thin Films in Low pH Electrolyte: Early Stages of Formation. Nanomaterials (Basel) 2021; 11:nano11081914. [PMID: 34443745 PMCID: PMC8398599 DOI: 10.3390/nano11081914] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Revised: 07/19/2021] [Accepted: 07/20/2021] [Indexed: 11/25/2022]
Abstract
The use of Ta/TaN barrier bilayer systems in electronic applications has been ubiquitous over the last decade. Alternative materials such as Co-W or Ru-W alloys have gathered interest as possible replacements due to their conjugation of favourable electrical properties and barrier layer efficiency at reduced thicknesses while enabling seedless Cu electroplating. The microstructure, morphology, and electrical properties of Cu films directly electrodeposited onto Co-W or Ru-W are important to assess, concomitant with their ability to withstand the electroplating baths/conditions. This work investigates the effects of the current application method and pH value of the electroplating solution on the electrocrystallisation behaviour of Cu deposited onto a Co-W barrier layer. The film structure, morphology, and chemical composition were studied by X-ray diffraction, scanning electron microscopy and atomic force microscopy, as well as photoelectron spectroscopy. The results show that the electrolyte solution at pH 1.8 is incapable of creating a compact Cu film over the Co-W layer in either pulsed or direct-current modes. At higher pH, a continuous film is formed. A mechanism is proposed for the nucleation and growth of Cu on Co-W, where a balance between Cu nucleation, growth, and preferential Co dissolution dictates the substrate area coverage and compactness of the electrodeposited films.
Collapse
Affiliation(s)
- Rúben F. Santos
- Department of Metallurgical and Materials Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal; (B.M.C.O.); (S.S.); (F.V.); (M.F.V.)
- LAETA/INEGI–Institute of Science and Innovation in Mechanical and Industrial Engineering, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal
- Correspondence:
| | - Bruno M. C. Oliveira
- Department of Metallurgical and Materials Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal; (B.M.C.O.); (S.S.); (F.V.); (M.F.V.)
- LAETA/INEGI–Institute of Science and Innovation in Mechanical and Industrial Engineering, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal
| | - Alexandre Chícharo
- International Iberian Nanotechnology Laboratory, Av. Mestre José Veiga, 4715-330 Braga, Portugal; (A.C.); (P.A.); (P.J.F.)
| | - Pedro Alpuim
- International Iberian Nanotechnology Laboratory, Av. Mestre José Veiga, 4715-330 Braga, Portugal; (A.C.); (P.A.); (P.J.F.)
- Centre of Physics, University of Minho, 4710-057 Braga, Portugal
| | - Paulo J. Ferreira
- International Iberian Nanotechnology Laboratory, Av. Mestre José Veiga, 4715-330 Braga, Portugal; (A.C.); (P.A.); (P.J.F.)
- Materials Science and Engineering Program, University of Texas at Austin, Austin, TX 78712, USA
- Mechanical Engineering Department and IDMEC, IST University of Lisbon, Av. Rovisco Pais, 1049-001 Lisboa, Portugal
| | - Sónia Simões
- Department of Metallurgical and Materials Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal; (B.M.C.O.); (S.S.); (F.V.); (M.F.V.)
- LAETA/INEGI–Institute of Science and Innovation in Mechanical and Industrial Engineering, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal
| | - Filomena Viana
- Department of Metallurgical and Materials Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal; (B.M.C.O.); (S.S.); (F.V.); (M.F.V.)
- LAETA/INEGI–Institute of Science and Innovation in Mechanical and Industrial Engineering, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal
| | - Manuel F. Vieira
- Department of Metallurgical and Materials Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal; (B.M.C.O.); (S.S.); (F.V.); (M.F.V.)
- LAETA/INEGI–Institute of Science and Innovation in Mechanical and Industrial Engineering, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal
| |
Collapse
|
2
|
Jefimovs K, Vila-Comamala J, Arboleda C, Wang Z, Romano L, Shi Z, Kagias M, Stampanoni M. Fabrication of X-ray Gratings for Interferometric Imaging by Conformal Seedless Gold Electroplating. Micromachines (Basel) 2021; 12:517. [PMID: 34066906 PMCID: PMC8147938 DOI: 10.3390/mi12050517] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Revised: 04/20/2021] [Accepted: 05/01/2021] [Indexed: 11/16/2022]
Abstract
We present a method to produce small pitch gratings for X-ray interferometric imaging applications, allowing the phase sensitivity to be increased and/or the length of the laboratory setup to be minimized. The method is based on fabrication of high aspect ratio silicon microstructures using deep reactive ion etching (Bosch technique) of dense grating arrays and followed by conformal electroplating of Au. We demonstrated that low resistivity Si substrates (<0.01 Ohm·cm) enable the metal seeding layer deposition step to be avoided, which is normally required to initiate the electroplating process. Etching conditions were optimized to realize Si recess structures with a slight bottom tapering, which ensured the void-free Au filling of the trenches. Vapor HF was used to remove the native oxide layer from the Si grating surface prior to electroplating in the cyanide-based Au electrolyte. Fabrication of Au gratings with pitch in the range 1.2-3.0 µm was successfully realized. A substantial improved aspect ratio of 45:1 for a pitch size of 1.2 µm was achieved with respect to the prior art on 4-inch wafer-based technology. The fabricated Au gratings were tested with X-ray interferometers in Talbot-Laue configuration with measured visibility of 13% at an X-ray design energy of 26 keV.
Collapse
Affiliation(s)
- Konstantins Jefimovs
- Paul Scherrer Institut, 5232 Villigen, Switzerland; (J.V.-C.); (C.A.); (Z.W.); (L.R.); (Z.S.); (M.K.); (M.S.)
- Institute for Biomedical Engineering, University and ETH Zürich, 8092 Zürich, Switzerland
| | - Joan Vila-Comamala
- Paul Scherrer Institut, 5232 Villigen, Switzerland; (J.V.-C.); (C.A.); (Z.W.); (L.R.); (Z.S.); (M.K.); (M.S.)
- Institute for Biomedical Engineering, University and ETH Zürich, 8092 Zürich, Switzerland
| | - Carolina Arboleda
- Paul Scherrer Institut, 5232 Villigen, Switzerland; (J.V.-C.); (C.A.); (Z.W.); (L.R.); (Z.S.); (M.K.); (M.S.)
- Institute for Biomedical Engineering, University and ETH Zürich, 8092 Zürich, Switzerland
| | - Zhentian Wang
- Paul Scherrer Institut, 5232 Villigen, Switzerland; (J.V.-C.); (C.A.); (Z.W.); (L.R.); (Z.S.); (M.K.); (M.S.)
- Institute for Biomedical Engineering, University and ETH Zürich, 8092 Zürich, Switzerland
| | - Lucia Romano
- Paul Scherrer Institut, 5232 Villigen, Switzerland; (J.V.-C.); (C.A.); (Z.W.); (L.R.); (Z.S.); (M.K.); (M.S.)
- Institute for Biomedical Engineering, University and ETH Zürich, 8092 Zürich, Switzerland
- Department of Physics and CNR-IMM, University of Catania, 64 via S. Sofia, 95123 Catania, Italy
| | - Zhitian Shi
- Paul Scherrer Institut, 5232 Villigen, Switzerland; (J.V.-C.); (C.A.); (Z.W.); (L.R.); (Z.S.); (M.K.); (M.S.)
- Institute for Biomedical Engineering, University and ETH Zürich, 8092 Zürich, Switzerland
| | - Matias Kagias
- Paul Scherrer Institut, 5232 Villigen, Switzerland; (J.V.-C.); (C.A.); (Z.W.); (L.R.); (Z.S.); (M.K.); (M.S.)
| | - Marco Stampanoni
- Paul Scherrer Institut, 5232 Villigen, Switzerland; (J.V.-C.); (C.A.); (Z.W.); (L.R.); (Z.S.); (M.K.); (M.S.)
- Institute for Biomedical Engineering, University and ETH Zürich, 8092 Zürich, Switzerland
| |
Collapse
|