Scratching by pad asperities in chemical–mechanical polishing

• Published in: CIRP annals Vol. 59; no. 1; pp. 329 - 332
• Main Authors: Saka, N., Eusner, T., Chun, J.-H.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Kidlington Elsevier Ltd 2010; Elsevier
• Subjects: Applied sciences; Defect; Exact sciences and technology; Fundamental areas of phenomenology (including applications); Mechanical contact (friction...); Mechanical engineering. Machine design; Physics; Polishing; Precision engineering, watch making; Semiconductor; Solid mechanics; Structural and continuum mechanics; Defect; Polishing; Semiconductor; Mechanical polishing; Semiconductor materials; Solid solid interface; Roughness; Chemical polishing; Mechanical properties; Nanoelectromechanical device; Mechanical contact; Metal; Rough surface; Experimental study; Coatings; Modeling; Surface treatment; Semiconductor device; Planarization; Friction; Friction coefficient; Lubrication; Microelectromechanical device
• ISSN: 0007-8506
• DOI: 10.1016/j.cirp.2010.03.113

In the fabrication of micro- and nano-scale semiconductor devices and electromechanical systems, the chemical–mechanical polishing (CMP) process is extensively employed. During the CMP process, undesirable scratches are produced on metal-interconnect and low- k-dielectric surfaces by the softer pad asperities. This paper presents contact mechanics models for the initiation of scratching in terms of the pad asperity geometry, the interfacial friction, and the mechanical properties of materials. Results of dry, wet and lubricated experiments on Cu coatings qualitatively validate the theoretical models. To mitigate scratching by pad asperities during CMP, the developed models suggest that the friction coefficient be kept below 0.2.