Experimental Research On The Properties Of SiO₂-Hydrosol Flows With Fluorescence Technique

Chemical mechanical polishing(CMP) is the only finish machine technique up to date for surface global planarization, which has been widely used for the manufacturing of integrated circuits(IC), hard disk, MEMS, optical glass, etc. But now Chemical mechanical polishing have a lot of problems, such as mechanism of process is not known yet, the model of CMP has not been established. Such problem has baffled the further development of CMP. The main ingredient of CMP slurry is SiO2-Hydrosol. To study the mechanism of CMP, it is very important to investigate of the SiO2-Hydrosol flows properties. In the present paper, the SiO2-Hydrosol flows properties with the help of fluorescence technique were explored. It mainly includes:The test rig for performing fluorescent analysis of was established, glass disk and polishing pad can rotate to simulate the pad and the wafer in CMP progress. We get excellent image with the use of UV incidence in a inclined direction. A self-balance equipment is developed to calibration the light. The image-picking capability is enhanced. It is the foundation of the succeeding experiments.When disk and pad rotate simultaneously or separately, track of fluid flows have been investigated. Results show that, when disk rotates, a new flow will be created. Direction and rate of the flow depend on the pose of polishing pad. It also control the rate of liquid took off by the disk. When polishing pad rotates, some liquid in the fringe can enter the center. The thickness of SiO2-Hydrosol flows properties in centrifugal spin of pad was explored. Results show that, when the distance of the polishing pad and the glass disk lies in the range of 0.3mm-0.9mm, the thickness of SiO2-Hydrosol in the center of the polishing pad will fall, and the trend is greatly manifested with the rate increase. But when the distance is below of 0.1mm, the thickness of SiO2-Hydrosol in the polishing pad will increase slightly.Then typical pressure distribution is numerically simulated. The pressure varies with the position in the radial direction. The maximum pressure occurs in the center, but with the speed increase, pressure will only rise slightly. When the distance is very small, elastic deformation of the polishing pad will occur. The elastic deformation will influence the thickness and the flow of liquid.