Polishing composition storage container
AssigneeCabot Microelectronics Corporation
InventorSteven K Grumbine
Life of this patent
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Abstract
The invention provides devices and methods for removing and trapping large and/or dense abrasive particles from a polishing slurry. The polishing slurry is introduced into a container and allowed to stagnate, thereby causing large and/or dense particles to separate from the slurry under the influence of gravity. The container includes a cavity or plurality of cavities defined by an inner surface of the container into which the separated particles sink. To prevent the large and/or dense particles from becoming re-suspended into the slurry, the size and shape of the cavity is relatively deep and narrow with respect to the large and/or dense particles, thus providing a trapping effect. The cavities do not effectively trap the smaller particles.
Claims29
A container for transporting and/or storing a polishing slurry having abrasive particles suspended therein, the container comprising:
- an interior surface defining a volume for storing the slurry, the interior surface further defining a cavity for retaining abrasive particles settling from the slurry;
- and
- an opening for receiving and/or emptying the slurry,
- wherein the container defines a volumetric capacity and the cavity is sized to retain about 0.1 wt. % to about 5 wt. % of the total abrasive particles in the slurry when the container is filled to capacity, and
- wherein the cavity has (a) a width from about 0.5 mm to about 10 mm,(b) a depth from about 0.5 mm to about 10 mm, or (c) a width from about 0.5 mm to about 10 mm and a depth from about 0.5 mm to about 10 mm.
A method of removing large and/or dense abrasive particles from a polishing slurry comprising abrasive particles suspended in a liquid carrier, the method comprising:
- providing a container having an interior surface defining a volume for storing the slurry and a cavity for retaining abrasive particles settling from the slurry;
- introducing the slurry into the container;
- allowing abrasive particles in the slurry to settle by gravimetric separation such that a portion of the abrasive particles is disposed in the cavity;
- removing the slurry from the container while retaining the portion of the abrasive particles in the cavity, wherein the retained abrasive particles are about 0.5 wt. % to about 5 wt. % of the total wt. % of abrasive particles in the slurry when the container is filled to capacity.
A polishing apparatus comprising the following:
- a container including an opening for receiving a slurry having abrasive particles suspended therein, the container further including an interior surface defining a volume for storing the slurry and a cavity, wherein the cavity is sized to retain about 0.1 wt. % to about 5 wt. % of the total abrasive particles in the slurry when the container is filled to capacity,
- a polishing tool including a platen, a polishing pad, and a carrier for holding a wafer to be polished;
- and
- a means for transporting the slurry from the container to the polishing tool.
Dependencies are inferred from the claim text.