Slurry recycling for chemical mechanical planarization 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 oulet 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 . A method of operating a polishing system, comprising:
 dispensing an abrasive-containing slurry on a pad using a first feeder and a second feeder;   processing a first fluid generated from the pad using a first flotation module;   storing a plurality of chemicals in a first tank of the first flotation module, wherein the plurality of chemicals comprise a frother and a collector configured to chemically bond with chemicals in the first fluid;   dispensing a gas into the first fluid using an inlet comprising one or more gas dispensers immersed in the first fluid in the first tank; and   fluidly connecting the outlet of the first tank to an upper portion of a second tank of a second flotation module.   
     
     
         2 . The method of  claim 1 , further comprising agitating the first fluid in the first tank using an agitator. 
     
     
         3 . The method of  claim 1 , further comprising precipitating by-products from the first fluid at a bottom portion of the first tank. 
     
     
         4 . The method of  claim 1 , further comprising altering the hydrophilicity or hydrophobicity of one or more chemicals of the plurality of chemicals with a modifier. 
     
     
         5 . The method of  claim 1 , further comprising collecting used slurry from the first fluid in an upper portion of the first tank. 
     
     
         6 . The method of  claim 1 , further comprising outputting, to the second tank, a recycled portion of the first fluid from a middle portion of the first tank. 
     
     
         7 . A method for recycling chemical mechanical planarization (CMP) waste slurry, the method comprising:
 storing a fluid comprising a frother in a tank;   providing the CMP waste slurry to the tank through a first inlet;   mixing the CMP waste slurry with the fluid in the tank;   dispensing a gas through a second inlet comprising one or more dispensers immersed in the fluid in the tank;   creating, in the tank, bubbles in the fluid using an agitator; and   outputting, via an outlet of the tank, a recycled waste slurry collected in a middle portion of the tank.   
     
     
         8 . The method of  claim 7 , further comprising filtering the recycled waste slurry by removing particles using one or more filter elements in a filter module connected to the outlet of the tank. 
     
     
         9 . The method of  claim 7 , further comprising controlling a temperature of the fluid and the CMP waste slurry in the tank using a heating device. 
     
     
         10 . The method of  claim 9 , further comprising controlling the temperature of the fluid and the CMP waste slurry in the tank at a temperature at or greater than room temperature. 
     
     
         11 . The method of  claim 7 , wherein mixing the CMP waste slurry with the fluid in the tank comprises agitating the CMP waste slurry and the fluid with the agitator. 
     
     
         12 . The method of  claim 7 , further comprising forming a precipitation at a bottom portion of the tank and discarding the precipitation through a drain. 
     
     
         13 . The method of  claim 7 , further comprising inspecting, by a detection module, physical and chemical properties of the recycled waste slurry, wherein the physical and chemical properties comprise conductivity, pH value, purity, and chemical composition. 
     
     
         14 . A method of operating a chemical mechanical planarization (CMP) system, comprising:
 supplying a first fluid and a second fluid, wherein the first fluid and the second fluid comprise a slurry;   polishing a substrate with the first and the second fluids;   collecting, by a flotation module, a third fluid created by polishing the substrate; and   extracting a fourth fluid from the third fluid, wherein the fourth fluid is fluidly connected to a source of the second fluid.   
     
     
         15 . The method of  claim 14 , wherein extracting the fourth fluid comprises agitating the third fluid with an agitator. 
     
     
         16 . The method of  claim 15 , wherein agitating the third fluid further comprises generating bubbles in the third fluid. 
     
     
         17 . The method of  claim 14 , further comprising removing particles in the fourth fluid via a filter module comprising one or more filter elements. 
     
     
         18 . The method of  claim 14 , further comprising inspecting, by a detection module, chemical and physical properties of the fourth fluid. 
     
     
         19 . The method of  claim 14 , further comprising dispensing a gas through one or more dispensers immersed in the third fluid. 
     
     
         20 . The method of  claim 14 , further comprising controlling a ratio of the first and second fluids for polishing the substrate.