Polishing apparatus and method for polishing substrate

Abstract

A polishing apparatus includes a platen, a polishing head, a first liquid source, a second liquid source, and a mixed liquid feeder. The platen includes a polishing pad having a polishing surface for polishing a substrate. The polishing head is disposed over the platen and configured to hold the substrate. The first liquid source is configured to provide first polishing liquid containing a first proportion of a component reacting with a material on the substrate. The second liquid source is configured to provide second polishing liquid containing a second proportion of the component less than the first proportion. The mixed liquid feeder is coupled to the first liquid source and the second liquid source, wherein the mixed liquid feeder is configured to mix the first polishing liquid and the second polishing liquid into a mixed polishing liquid and feed the mixed polishing liquid to the polishing pad.

What is claimed is: 
     
         1 . A polishing apparatus, comprising:
 a platen comprising a polishing pad having a polishing surface for polishing a substrate;   a polishing head disposed over the platen and configured to hold the substrate;   a first liquid source configured to provide first polishing liquid containing a first proportion of a component reacting with a material on the substrate;   a second liquid source configured to provide second polishing liquid containing a second proportion of the component less than the first proportion; and   a mixed liquid feeder coupled to the first liquid source and the second liquid source, wherein the mixed liquid feeder is configured to mix the first polishing liquid and the second polishing liquid into a mixed polishing liquid and feed the mixed polishing liquid to the polishing surface of the polishing pad.   
     
     
         2 . The polishing apparatus as claimed in  claim 1 , wherein the mixed liquid feeder comprises a mixing chamber coupled to the first liquid source and the second liquid source for mixing the first polishing liquid and the second polishing liquid therein and comprising an outlet from which the mixed polishing liquid is discharged. 
     
     
         3 . The polishing apparatus as claimed in  claim 1 , wherein the mixing chamber further comprises a first inlet coupled the first liquid source for introducing the first polishing liquid into the mixing chamber and a second inlet coupled to the second liquid source for introducing the second polishing liquid into the mixing chamber. 
     
     
         4 . The polishing apparatus as claimed in  claim 1 , further comprising a conditioning device disposed over the platen and configured for conditioning the polishing pad. 
     
     
         5 . The polishing apparatus as claimed in  claim 1 , wherein the component comprises abrasive, a corrosion inhibitor for reducing a corrosion rate of the material, a corrosion promoter for increasing a corrosion rate of the material. 
     
     
         6 . The polishing apparatus as claimed in  claim 1 , further comprising a sensing device configured to detect a presence of the material on the substrate. 
     
     
         7 . The polishing apparatus as claimed in  claim 6 , further comprising a controller coupled to the sensing device and the mixed liquid feeder, wherein the controller controls the mixed liquid feeder to mix the first polishing liquid with a first amount and the second polishing liquid with a second amount less than the first amount when the sensing device detects that the presence of the material is less than a predetermined amount. 
     
     
         8 . The polishing apparatus as claimed in  claim 7 , wherein the component comprises a corrosion inhibitor for reducing a corrosion rate of the material. 
     
     
         9 . The polishing apparatus as claimed in  claim 6 , wherein the sensing device comprises an eddy current monitoring device, a dielectric motor, or an optical sensing device. 
     
     
         10 . A method for polishing a substrate, comprising:
 providing the substrate over a platen of a polishing apparatus, wherein the substrate comprises a material over a semiconductor substrate;   pressing the substrate against a polishing pad of the platen;   performing a polishing process by the polishing pad while providing a mixed polishing liquid to remove a portion of the material, wherein the mixed polishing liquid is a mixture of first polishing liquid containing a first proportion of a component reacting with the material and second polishing liquid containing a second proportion of the component less than the first proportion.   
     
     
         11 . The method as claimed in  claim 10 , further comprising:
 detecting a presence of the material before the mixed polishing liquid is provided;   mixing a first polishing liquid with a first amount and a second polishing liquid with a second amount, wherein the first amount and the second amount is determined according to the presence of the material.   
     
     
         12 . The method as claimed in  claim 11 , wherein when the presence of the material is detected to be less than a predetermined amount, the first amount is determined to be greater than the second amount. 
     
     
         13 . The method as claimed in  claim 11 , wherein when the presence of the material is detected to be greater than or substantially equal to a predetermined amount, the first amount is determined to be less than or substantially equal to the second amount. 
     
     
         14 . The method as claimed in  claim 10 , wherein the component comprises abrasive or corrosion inhibitor when the material comprises dielectric material. 
     
     
         15 . The method as claimed in  claim 10 , wherein the component comprises corrosion promoter or corrosion inhibitor when the material comprises tungsten, molybdenum, ruthenium, or copper. 
     
     
         16 . The method as claimed in  claim 10 , wherein the first proportion of the component is at least ten times more than the second proportion of the component. 
     
     
         17 . A method for polishing a substrate, comprising:
 providing the substrate over a polishing pad of a polishing apparatus, wherein the substrate comprises a material;   pressing the substrate against the polishing pad by a polishing head;   performing a polishing process by the polishing pad while providing a mixed polishing liquid to remove a portion of the material, wherein the mixed polishing liquid is a mixture of first polishing liquid containing a first proportion of corrosion inhibitor and second polishing liquid containing a second proportion of the corrosion inhibitor less than the first proportion.   
     
     
         18 . The method as claimed in  claim 17 , further comprising:
 detecting a presence of the material before the mixed polishing liquid is provided;   mixing the first polishing liquid with a first amount and the second polishing liquid with a second amount, wherein the first amount and the second amount is determined according to the presence of the material.   
     
     
         19 . The method as claimed in  claim 18 , wherein when the presence of the material is detected to be less than a predetermined amount, the first amount is determined to be greater than the second amount. 
     
     
         20 . The method as claimed in  claim 18 , wherein when the presence of the material is detected to be greater than or substantially equal to a predetermined amount, the first amount is determined to be less than or substantially equal to the second amount.