Engineering Surface Texture of Pads for Improving CMP Performance of Sub-10 nm Nodes. (12th October 2020)

• Record Type: Journal Article
• Authors: Khanna, Aniruddh J.; Kakireddy, Veera Raghava; Fung, Jason; Yamamura, Mayu; Jawali, Puneet; Chockalingam, Ashwin; Baradanahalli Kenchappa, Nandan; Redfield, Daniel; Bajaj, Rajeev
• Is Part Of: ECS journal of solid state science and technology. Volume 9:Number 10(2020)
• Publication Date: 2020-10-12
• Subjects: CMP -- Surface Texture -- Chemical mechanical planarization -- Chemical mechanical polishing -- Microelectronics - Semiconductor Processing -- Surface roughness -- CMP pad; Solid state chemistry -- Periodicals; Electronics -- Materials -- Periodicals; Electrochemistry -- Periodicals; 541.0421
• DOI: 10.1149/2162-8777/abbcb5
• Languages: English
• ISSNs: 2162-8777

Abstract

Abstract : Shallow trench isolation (STI) chemical mechanical planarization (CMP) will continue to be a critical step in the device fabrication of future technology nodes. A CMP process needs the right combination of pad, slurry, and pad conditioner to be able to deliver the best performance. Engineered pad surface along with usage of non-Prestonian ceria slurries can be used to solve key STI CMP challenges. Herein, it is demonstrated that relative to a reference pad, reducing and optimizing pad surface roughness, can help improve material removal rate by 26%–95% at different wafer pressures, lower the dishing by 34%–51% for feature size of 50–200 μ m, thereby leading to an improved planarization performance. This work illustrates that the surface texture of a pad can be used to achieve a stable dishing range over different feature scales for various over polish times. Also, optimizing the pad surface roughness minimizes slurry consumption by 33% and enables polishing at a lower downforce. Further, it is demonstrated that relative to a reference pad, defectivity can be improved up to 85% for the pad without impacting the planarization performance by reducing the pad material hardness and polishing at an optimized pad surface roughness.