System, method, and apparatus for wetting slurry delivery tubes in a chemical mechanical polishing process to prevent clogging thereof

A system for chemical mechanical polishing, the system comprising:

• a polishing pad for polishing a workpiece;
• a high pressure spray bar located adjacent the polishing pad and having a distal end and a passage formed through a length of the high pressure spray bar;
• a plurality of slurry delivery tubes mounted to the high pressure spray bar, each of the slurry delivery tubes having an opening on a distal end thereof for dispensing slurry to polish the workpiece on the polishing pad, and the distal ends of the slurry delivery tubes extend beyond the distal end of the high pressure spray bar;
• a nozzle mounted to the distal end of the high pressure spray bar adjacent the distal ends of the slurry delivery tubes, the nozzle being adapted to dispense a mist of deionized water directly onto the distal ends of the slurry delivery tubes for moisturizing the distal ends of the slurry delivery tubes to prevent clogging thereof by the slurry;
• wherein
• the nozzle comprises a fan-type spray nozzle having an offset angle of 15° to avoid overspraying the slurry delivery tube and limit the distribution of the mist to a tip of the slurry delivery tube;
• and wherein
• the nozzle dispenses the mist each time the slurry bar automatically cycles to dispense slurry to keep the distal ends of the slurry delivery tubes wet enough to prevent the slurry from drying in and clogging the slurry delivery tubes, and the distal ends of the slurry delivery tubes are automatically wetted between slurry dispensations without intervention.

A method of chemical mechanical polishing, the method comprising:

• (a) providing a high pressure spray bar with a slurry delivery tube, each having a distal end located adjacent the other;
• (b) mounting a nozzle in the distal end of the high pressure spray bar;
• (c) positioning a workpiece on a polishing pad;
• (d) dispensing a slurry onto the workpiece and polishing pad from the distal end of the slurry delivery tube;
• (e) moisturizing the distal end of the slurry delivery tube with a moisturizer from the nozzle by dispensing a mist of deionized water directly onto the distal end of the slurry delivery tube each time the high pressure spray bar automatically cycles to dispense slurry to keep the distal end of the slurry delivery tube wet enough to prevent the slurry from drying in and clogging the slurry delivery tube, such that the distal end of the slurry delivery tube remains wetted between slurry dispensations without intervention;
• (f) chemically mechanically polishing the workpiece with the polishing pad and the slurry;
• and then
• (g) repeating step (e) to remoisturize the distal end of the slurry delivery tube to prevent clogging thereof by the slurry.