An arrangement and method for managing the tribology associated with a chemical mechanical planarization (CMP) process continuously monitors and modifies the properties of a polishing slurry in order to assist in controlling the removal rate associated with the CMP process. The viscosity of slurry as it leaves the CMP system ("spent slurry") and the material removal rate associated with the semiconductor wafer are measured, and then the viscosity of the incoming slurry is adjusted if the measured material removal rate differs from a desired removal rate. If the removal rate is considered to be too fast, the viscosity of the fresh slurry being dispensed onto polishing pad is decreased; alternatively, if the removal rate is too slow, the viscosity is increased. As an alternative to modifying the viscosity of the slurry (or, perhaps in addition to modifying the viscosity), a lubricant may be added to the slurry to slow down the removal rate.
The evacuation properties of an abrasive disk are improved by forming its apertures to exhibit a configuration that will direct process fluids onto or away from a workpiece (or contact) interface through capillary action, surface tension/affinity, and/or boundary layer pump actions. The capillary action is accomplished by modifying the geometries of the apertures to form capillary tubes, where the orientation and lift angle of the capillary tubes is controlled to improve the flow of relatively thin layers of liquids. The surface tension/affinity between a liquid material and the abrasive disk is controlled by modifying the through-hole apertures to exhibit a serrated inner surface, which will decrease the attraction between the material of the abrasive disk and the process liquid. A plurality of apertured disks may be stacked, and their respective apertures properly arranged on each surface, to create a Tesla pump such that the kinetic energy associated with rotation of the disk assembly will preferentially bias both the vertical and tangential flow of liquids between the working surface and the disk assembly.
B24D 7/00 - Bonded abrasive wheels, or wheels with inserted abrasive blocks, designed for acting otherwise than only by their periphery, e.g. by the front faceBushings or mountings therefor
B24D 3/34 - Physical features of abrasive bodies, or sheets, e.g. abrasive surfaces of special natureAbrasive bodies or sheets characterised by their constituents characterised by additives enhancing special physical properties, e.g. wear resistance, electric conductivity, self-cleaning properties
B24D 99/00 - Subject matter not provided for in other groups of this subclass
3.
IN-LINE EFFLUENT ANALYSIS METHOD AND APPARATUS FOR CMP PROCESS CONTROL
An apparatus and method for collecting and analyzing the effluent stream created by a chemical mechanical planarization (CMP) process performs a continuous measurement of at least one effluent characteristic and integrates the results over time to create a volumetric analysis of the planarization process. The volumetric analysis can be used as feedback/feedforward signals to control the planarization process itself (e.g., endpoint detection based upon an known initial thickness of film material), create alarm signals for out-of-range measurements, and/or waste stream indicators useful in treating the effluent prior to discharge (e.g., determining a pH correction).
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