Effect of integrated anneal optimizations of electroplated Cu thin films interconnects. (November 2020)

• Record Type: Journal Article
• Authors: Wahab, Y.A.; Johan, M.R.; Hamizi, N.A.; Akbarzadeh, O.; Chowdhury, Z.Z.; Sagadevan, S.
• Is Part Of: Microelectronics and reliability. Volume 114(2020)
• Publication Date: 2020-11
• Subjects: Electronic apparatus and appliances -- Reliability -- Periodicals; Miniature electronic equipment -- Periodicals; Appareils électroniques -- Fiabilité -- Périodiques; Équipement électronique miniaturisé -- Périodiques; Electronic apparatus and appliances -- Reliability; Miniature electronic equipment; Periodicals; 621.3815
• DOI: 10.1016/j.microrel.2020.113887
• Languages: English
• ISSNs: 0026-2714

Abstract

Abstract: The significance of this paper is to emphasize wafer scale electrochemical plating process optimizations to demonstrate yield-limiting defects reduction. A multiple process enhancement has been implemented to reduce metal "stress-induced" voids, crater defects, Cu mound, as well as other killer defects. The troubleshooting is involving thermal anneal conditions with the modifications of in-situ anneal to integrated helium anneal by demonstrating capability of ramp rates during heating and cooling stages. Result shows a significant defects reduction and reveals the dependence of anneal soak time particularly for types of defects. Due to this integration of concerns, we further investigate the adoption of integrated diffuser to quantify the best degree of uniformity and high resistivity to enhance an even current distribution on the wafer. The results show that uniformity of the deposited film has been improved significantly with an increasing trend with anolyte lifetime. The origin of yield-limiting ECP defects of various range soaking time effects after CMP partial polish was identified and greatly overcome with the improved ECP system comprising an integrated modification. Highlights: The significance of this paper is to emphasize wafer scale electrochemical plating process. Process optimizations to demonstrate yield-limiting defects reduction. The modifications of in-situ anneal to integrated helium anneal by demonstrating capability of ramp rates. The results show that uniformity of the deposited film has been improved significantly The yield-limiting defects with soaking time effects was identified and greatly overcome.