Slurry recycling in CMP apparatus
AssigneeIntegrated Process Equipment Corp.
InventorsJohn A. Adams, Gerald A. Krulik, C. Randall Harwood
Life of this patent
Estimating the term…
Abstract
Recycled slurry is continuously blended with the slurry in use to provide a consistent polishing rate while consuming or discarding a small fraction of the slurry flowing continuously across the polishing pad. The slurry is recovered in a catch ring and fed to a recycle loop to blend the recovered slurry with fresh slurry, rejuvenating chemicals, or water; test the blend; filter the blend; and return the blend to the polishing pad. The volume returned to the pad slightly exceeds the volume recovered, causing the catch ring to overflow. Rinse water is recycled in the same fashion to keep the polishing pad wet between polishing cycles.
Claims28
In CMP apparatus including a polishing pad, the improvement comprising:
- a catch ring at least partially surrounding said pad for receiving and containing used slurry as said slurry flows off said pad;
- a first tube for withdrawing a portion of said used slurry from said catch ring through a first end of said first tube;
- a mixing manifold having an output, a first input coupled to said first tube and a second input for coupling to a source of fresh slurry, said mixing manifold blending the fluids supplied to the inputs thereof to produce recycled slurry;
- and
- a second tube, coupled to the output of said mixing manifold for returning said recycled slurry to said pad.
A method for recycling slurry in CMP apparatus in which the slurry is applied to a polishing pad, said method comprising the steps of:
- at least partially surrounding the pad with a catch ring to contain the slurry that flows off the pad;
- providing a mixing manifold having an output, a first input, and a second input;
- withdrawing used slurry from the ring to the first input supplying fresh slurry to the second input.
- blending the used slurry with the fresh slurry in the mixing manifold to produce recycled slurry;
- and
- returning the recycled slurry from the output to the mixing manifold to the pad.
Dependencies are inferred from the claim text.