Calculation on Temperature Rise of CMP Process: Roughness Effects Considered
Chemical mechanical polishing (CMP) has been widely accepted in modern integrated circuit (IC) industries and hard disk manufacturing processes, to insure wafer surface with high level of global and local planarity required. In CMP process, temperature rise has two-edged influences: temperature-rise accelerates the chemical activity and the motion of nano-particles contained in the slurry through which material removal ratio (MRR) is enhanced; the other side of the same coin is, however, that it will soften the pad surface and subsequently reduce the MRR. Furthermore, it is found that temperature-rise would cause agglomeration of nano-particles, which would cause the wafer surface defect. The net effects of temperature thus should be under investigation with scrutiny. In an attempt to study the temperature variation and influencing rule, in this paper we firstly establish the flow equation considering pad roughness, coupling the energy equation on the basis of thermodynamics. Then, by taking numerical simulation which is carried out to give out the temperature distribution of conventional CMP process. The results show that temperature-rise in the CMP process is very minor. The research will surely shed some lights on the mechanism of CMP and lay a feasible foundation for possible future utilization.
Jitai NIU, Zuyan LIU, Cheng JIN and Guangtao Zhou
W. Ye and C. H. Zhang, "Calculation on Temperature Rise of CMP Process: Roughness Effects Considered", Materials Science Forum, Vols. 575-578, pp. 1348-1353, 2008