Apparatus for polishing a wafer

Abstract

A chemical mechanical polishing (CMP) apparatus includes a polishing pad, a platen, and a cleaning apparatus which provides a cleaning fluid for cleaning the polishing head. The cleaning apparatus includes a shaft located outside a periphery of the polishing pad, and an arm mounted to the shaft and extending over the polishing pad such that a bottom surface of the arm confronts the polishing surface of the polishing pad. Further, a cleaning fluid path is defined in the arm along a length of the arm, and first drop holes are defined in the arm which are fluidly connected to the cleaning fluid path and which drop cleaning fluid onto the polishing surface of the polishing pad.

What is claimed is:  
     
         1 . An apparatus for planarizing wafers, comprising: 
 a polishing station having a platen to which a polishing pad having a polishing surface is attached;    a polishing head located over the polishing surface of the polishing pad; and    a cleaning apparatus which supplies a cleaning fluid onto the polishing pad, and which includes a shaft located outside a periphery of the polishing pad, and an arm mounted to the shaft and extending over the polishing pad such that a bottom surface of the arm confronts the polishing surface of the polishing pad;    wherein a cleaning fluid path is defined in the arm along a length of the arm, and wherein first drop holes are defined in the arm which are fluidly connected to the cleaning fluid path and which drop cleaning fluid onto the polishing surface of the polishing pad.    
     
     
         2 . The apparatus as recited in  claim 1 , wherein the bottom surface of the arm is a flat surface.  
     
     
         3 . The apparatus as recited in  claim 1 , wherein the bottom surface of the arm is a curved surface.  
     
     
         4 . The apparatus as recited in  claim 2 , wherein the first drop holes are formed at the bottom surface of the arm.  
     
     
         5 . The apparatus as recited in  claim 3 , wherein the first drop holes are formed at the bottom surface of the arm.  
     
     
         6 . The apparatus as recited in  claim 1 , wherein the arm further includes at least one second drop hole which is fluidly connected to the cleaning fluid path and which drops the cleaning fluid onto a side surface of the polishing head.  
     
     
         7 . The apparatus as recited in  claim 6 , wherein the second drop hole is located at a distal end of the arm adjacent to the side surface of the polishing head.  
     
     
         8 . The apparatus as recited in  claim 1 , wherein at least one slurry path is further defined in the arm along the length of the arm, and wherein the apparatus further includes a nozzle fluidly connected to the slurry path to supply slurry onto the polishing pad.  
     
     
         9 . The apparatus as recited in  claim 8 , wherein the nozzle is inserted into a receiving hole which is defined in the arm and which has a hole, communicating with the slurry path, into which the nozzle is inserted.  
     
     
         10 . The apparatus as recited in  claim 1 , wherein the arm has a first portion which extends lengthwise from the base, a second portion which extends lengthwise at an angle from the first portion, and a third portion which extends lengthwise at an angle from the second portion.  
     
     
         11 . The apparatus as recited in  claim 10 , wherein the arm is formed of a monolithic body.  
     
     
         12 . The apparatus as recited in  claim 1 , wherein the cleaning water is a de-ionized (DI) water.