Enhanced Grain Growth of Electroplated Copper on Cobalt-Containing Seed Layer

Abstract

Cu films with low impurities were electroplated on pure Cu, CuCo alloy and electrodeposited Co seed layers to study the room temperature grain growth behavior. As-evaporated Cu and CuCo alloy seed layers showed a significant enhancement effect on the Cu recrystallization compared with sputtered Cu seed layers and post-annealed evaporated seed layers. The impact of the electrodeposited Co seed layer on the Cu grain growth was found to be dependent on the Co plating chemistry and on the thickness of the Co film. Co films plated in the absence and presence of saccharin showed a crystal structure of fcc and hcp, respectively. While the former showed little to no impact on the Cu recrystallization, the later was found to enhance or hinder the Cu recrystallization depending on the thickness of the Co. Studies on a Cu/Co sandwich stack structure showed that the recrystallization started at the top Cu layer, proceeding to the middle layer and then to the bottom layer.

Self-Terminated Electrodeposition of Ni, Co, and Fe Ultrathin Films

“…11−13 In addition to energy conversion and storage technology, the magnetic properties of iron group alloys and oxides are central to information storage and sensing technologies and will be important building blocks in emerging spintronic applications. 14−17 The metallurgical and thermal properties of iron group alloys are also important in microelectronics: from Co liners for Cu interconnects 18,19 to constituents of active and passive components in microelectromechanical (MEMS) devices, such as low coefficient of thermal expansion alloys, inductors, etc. 20 Thin films of iron group elements and alloys are routinely prepared on planar substrates using physical vapor deposition methods such as evaporation or sputtering or by less expensive electrochemical deposition.…”

“…Thin films of iron group metals (Ni, Co, Fe), alloys, and their oxide derivatives are of interest to a wide range of technical endeavors from energy conversion to microelectronics. The oxides and oxyhydroxides are among the best known oxygen evolution catalysts, while the metals, alloys, and hydroxides make effective cathodes for hydrogen production from alkaline water electrolysis. − Likewise, the proton intercalation properties of the oxide and hydroxide phases are important in battery reactions and supercapacitors. − In addition to energy conversion and storage technology, the magnetic properties of iron group alloys and oxides are central to information storage and sensing technologies and will be important building blocks in emerging spintronic applications. − The metallurgical and thermal properties of iron group alloys are also important in microelectronics: from Co liners for Cu interconnects , to constituents of active and passive components in microelectromechanical (MEMS) devices, such as low coefficient of thermal expansion alloys, inductors, etc…”

Role of 1,2,4-Triazole in Co/Cu Removal Rate Selectivity and Galvanic Corrosion during Barrier CMP

“…Cobalt not only has lower resistivity and higher thermal stability than tantalum, but also has good step coverage and adhesion for copper line, 4,7,8 making the wiring copper directly electroplated on cobalt without copper seed layer. [9][10][11] However, removal rate selectivity control and galvanic corrosion reduction between cobalt and copper are the key technology gaps during cobalt barrier chemical mechanical polishing (CMP) process. In general, the barrier removal rate is lower under the synergistic effect of chelating agents, abrasive and oxidant, but high removal rate selectivity of cobalt to copper is quite significant for reducing dishing defects, which requires that the removal rate of barrier is higher than that of copper.…”

Galvanic Corrosion Inhibition from Aspect of Bonding Orbital Theory: Case Study of Copper/Ruthenium Coupled Film Using 3- Pyridinecarboxylic Acid

“…As shown in Fig. 2b, the electron con gurations of metal ions in oxidized Cu and Ru lms are Cu + : (Ar)3d 10 and Ru 4+ : (Kr)4d 4 , respectively. As a result, there is a difference in terms of π-back bonding which participates in the delocalized π-electrons present in planar cyclic hydrocarbon molecules of the pyridine ring structure and lled d-orbital of metal ions (Fig.…”

“…Furthermore, due to the compatibility between Cu and Ru metals, Cu could be deposited directly onto the Ru lm via electroplating without requiring a seed layer, which is advantageous in terms of cost reduction and surface quality of the deposited lm. [9][10][11]. For the application of the Ru metal in barrier structure, the CMP performance is required to 1:1 selectivity of removal rate on Ru and Cu metal lms.…”