Diamond disc pad conditioning process control

Pad conditioning is primarily a highly mechanical process. Its effects on the polishing process are dictated by the conditioning kinematic parameters as shown in Table 13.2 and other parameters such as pad and conditioner property parameters [40,47—49] listed in Table 13.3. Automatic control of the process has been achieved through controllers that adjust the settings of the equipment during operation [50—51]. 

Pressure Conditioning pressure is related to the down force applied to the conditioner disc. Pad wear rate increases with the conditioning contact pressure between the diamond disc and the polishing pad. 

Velocity This is the combination of all the planar motions of the pad and the conditioner. Pad wear rate increases with conditioning velocity. On the other hand, surface roughness would be more mgged because of higher conditioning velocity. Wafer MRR increases with pad speed. 

Time This is the time spent at each region that the disc conditions. Chen [17] stated that the acmal conditioning time is the main determinant of the amount of pad wear. Also, when the conditioner stays at one region for a longer time, local pad thickness would reduce and local conditioner contact pressure also reduces. As a result, MRR gradually reduces with longer conditioning time. 

Sweeping pattern This is described by the direction or trajectory in which the disc moves usually in allocated regions on the pad and the frequency of sweeping oscillation. The trajectory may be linear or semicircular. 

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