| The objective of this research is examine the fluid mechanics of chemical mechanical planarization (CMP). These slurry flow fields are an integral component to increase the understanding of CMP, as they affect the fundamental processes involved in the material removal and polishing.;In this thesis I describe the design and implementation of flow visualization methods, including the analysis of basic video data and Particle Image Velocimetry, or PIV, into the Tufts University CMP testing platform. All experiments were performed on a half scale Struers RotoPol-31 table top polisher using BK-7 glass wafers. A diluted Cabot Microelectronics SC-1 slurry with silica abrasive particles was utilized. Fruedenburg FX9 Flat, FX9 XY, and Cabot DC100 AC grooved polishing pads were tested.;The basic visualization experiments provided a qualitative analysis of the flow as a function of injection point, pad grooving, down force, and wafer/conditioner rotation. These basic data were made quantitative by applying the PIV method, which calculates velocity vectors over an entire region of flow. An in-house processing program was developed in LabView which produces velocity data to an accuracy of 1%. PIV analysis indicated a region of high slurry velocities, ranging from 0:1 to 0:4 cm/s, next to the wafer followed by a larger stagnation region of equal or lower velocity. The increased slurry speed near the wafer appeared to result from both the wafer rotation and the force of the incoming slurry. The stagnation region may have resulted from an excessive amount of slurry attempting to enter the region of space between the wafer and pad, resulting in the formation of a bow wave. After the stagnation region, the slurry velocity grew steadily with distance from the wafer, mimicking the linear speed of the platen. |
