Mechanical interactions and their effects on chemical mechanical polishing

• Published in: IEEE transactions on semiconductor manufacturing Vol. 14; no. 3; pp. 207 - 213
• Main Authors: Lei Shan, Chunhong Zhou, Danyluk, S.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: New York, NY IEEE 01.08.2001; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Applied sciences; Chemicals; Conducting materials; Contact stresses; Dielectric materials; Electronics; Exact sciences and technology; Fluid pressure; Friction; Integrated circuit interconnections; Mathematical models; Microelectronic fabrication (materials and surfaces technology); Nonuniformity; Planarization; Polishing; Pressure measurement; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Semiconductors; Silicon; Stress; Surface finishing; Wafers; Microelectronic fabrication; Friction; Contact stress; Hydrostatic pressure; Silicon; Chemical mechanical polishing; Wafer; Surface treatment
• ISSN: 0894-6507; 1558-2345
• DOI: 10.1109/66.939815

Mechanical interactions, such as contact stress and fluid pressure are of extreme importance in silicon wafer polishing, especially for the wafer-scale planarity of the finished surfaces. In this paper, the measurements of interfacial fluid pressure and friction, as well as their dependence on some major process variables, are presented. A nonuniform subambient fluid pressure was measured, and the resulting wafer/pad contact stress, obtained by combining the effects of both applied normal load and interfacial fluid pressure, is determined. An analytical model was developed to predict the magnitude and distribution of the interfacial fluid pressure. The results of polishing experiments show good evidence of the effects of this subambient fluid pressure on with in-wafer nonuniformity (WIWNU). By properly designing the polishing process variables, the fluid pressure may be tailored, and a relatively uniform material removal can be achieved.