Slurry recycling for chemical mechanical polishing system

Abstract

The present disclosure describes an apparatus and a method for a chemical mechanical polishing (CMP) process that recycles used slurry as another slurry supply. The apparatus includes a pad on a rotation platen, a first feeder and a second feeder where each of the first and the second feeder is configured to dispense a slurry on the pad, and a flotation module configured to process a first fluid sprayed from the pad. The flotation module further includes an outlet fluidly connected to the second feeder and configured to output a second fluid, and a first tank configured to store a plurality of chemicals where the plurality of chemicals include a frother and a collector configured to chemically bond with chemicals in the first fluid.

What is claimed is: 
     
         1 . An apparatus, comprising:
 a tank configured to store a first fluid comprising a frother, wherein the tank comprises:
 an inlet configured to provide a second fluid to the tank; 
 a first outlet configured to output a recycled slurry; 
 a second outlet fluidly connected to a drain; and 
   an agitator configured to cause the frother to create bubbles in the first fluid in the tank.   
     
     
         2 . The apparatus of  claim 1 , wherein the first outlet is fluidly connected to an inlet of an other tank. 
     
     
         3 . The apparatus of  claim 1 , wherein the first fluid further comprises:
 a collector to with bond one or more chemicals in the second fluid; and   a modifier to alter a hydrophobicity or hydrophilicity of the one or more chemicals in the second fluid.   
     
     
         4 . The apparatus of  claim 3 , wherein:
 the frother comprises alcohol (C 5 H 11 OH), phenol (C 6 H 5 OH), wood oil including pinene (C 10 H 16 ), terpineol (C 10 H 17 OH), citronellal (C 10 H 18 O), or an inorganic material;   the collector comprises sodium dithiophosphate (Na 3 PS 2 O 2 ), ethyl amine (NC 2 C 2 H 5 ), a fatty acid, a soap with a molecular structure that includes R—COOH, or R-COO-M, wherein R represents a chain of hydrocarbon and M represents a metal; and   the modifier comprises a pH adjuster, a dispersant, a molecule that includes phosphate (PO 3   − ), an agglomerant, an inhibitor, an activator, or an inorganic material.   
     
     
         5 . The apparatus of  claim 1 , wherein the agitator comprises a fan supported by a bearing, an ultrasonic device, or an oscillator device. 
     
     
         6 . The apparatus of  claim 1 , wherein the tank further comprises an other inlet configured to provide a gas into the tank. 
     
     
         7 . The apparatus of  claim 1 , further comprising an other tank fluidly connected to an upper portion of the tank, wherein the other tank is fluidly connected to the drain. 
     
     
         8 . An apparatus, comprising:
 a first tank comprising a first inlet and a second inlet;   a second tank fluidly connected to the first tank;   a combination of fluids in the first and second tank to recycle a slurry; and   an agitator to create bubbles in the combination of fluids.   
     
     
         9 . The apparatus of  claim 8 , wherein the first inlet is configured to feed a used chemical mechanical polishing (CMP) slurry to the first tank. 
     
     
         10 . The apparatus of  claim 8 , wherein the combination of fluids comprises:
 a frother to facilitate formation of bubbles in the first tank;   a modifier to alter a hydrophilicity or hydrophobicity of a waste molecule in used chemical mechanical polishing (CMP) slurry; and   a collector to form an intermediate molecule by attaching to the frother.   
     
     
         11 . The apparatus of  claim 10 , wherein the bubbles comprise a non-dissolvable gas and the frother and collector accumulate at a boundary of the bubbles. 
     
     
         12 . The apparatus of  claim 11 , wherein the bubbles with the attached frother and collector attaches to a waste molecule in the CMP slurry. 
     
     
         13 . The apparatus of  claim 12 , wherein the second tank is configured to collect an agglomeration of the waste molecule with the attached frother and collector to the bubbles for disposal to a drain. 
     
     
         14 . The apparatus of  claim 8 , wherein the agitator comprises a fan supported by a bearing, an ultrasonic device, or an oscillator device. 
     
     
         15 . A system, comprising:
 a first flotation module comprising a first mixing tank, a first inlet, a second inlet, a first outlet, and a second outlet;   a second flotation module comprising a second mixing tank, a third inlet, a third outlet, and a fourth outlet, wherein the first outlet of the first mixing tank is fluidly connected to the third inlet of the second mixing tank;   a first agitator configured to create bubbles in the first mixing tank; and   a second agitator configured to create bubbles in the second mixing tank.   
     
     
         16 . The system of  claim 15 , wherein the first inlet is configured to input a used slurry to the first tank. 
     
     
         17 . The system of  claim 15 , wherein the third outlet of the second mixing tank is configured to output a recycled chemical mechanical polishing (CMP) slurry from a middle portion of the second mixing tank. 
     
     
         18 . The system of  claim 15 , wherein the first and second mixing tanks are configured to hold a chemical fluid comprising deionized water, a frother, a modifier, and a collector. 
     
     
         19 . The system of  claim 16 , wherein the first and second mixing tanks are configured to collect a waste molecule of the used slurry collects in a top portion of the first and second mixing tanks. 
     
     
         20 . The system of  claim 19 , wherein the second outlet of the first mixing tank and the fourth outlet of the second mixing tank are configured to drain the waste molecule.