Study on Lubricating Behavior in Chemical Mechanical Polishing

Abstract

Chemical mechanical polishing (CMP) has become the most widely used planarization technology in the metal and hard-brittle crystal substrate manufacturing process. In this paper, the distinguish method of lubricating behavior in CMP had been analyzed in theory firstly. Then, the tests of CMP with silicon wafer and deposited copper wafer at different polishing pressure had been done. By the test results, the Stribeck curves obtained showed obvious smooth. But in normal CMP conditions, the friction coefficient of polishing area was above 0.1. By analyzing the experimental results, it was concluded that the lubrication state in CMP interface is belong to the boundary lubrication and the material removal is the process of bringing and removed of the chemical reaction boundary lubricating film on hard-brittle crystal substrate surface constantly. The contact form between the workpiece and the polishing pad is the solid-solid contact. These results will provide theoretical guide to further understand the material removal mechanism of in hard-brittle crystal substrate CMP.

High Rate Chemical Mechanical Polishing of Boron-Doped Polycrystalline Silicon

“…This can be explained by considering the fact that at extremely high velocities and low flow rates the lubrication regime varies from the boundary lubrication to the dry lubrication regime. 33 This occurs because at high velocity and low flow rates there is not enough slurry to cover the interface between the wafer and the pad. There is contact between the pad asperities and the wafer.…”