Methods and apparatus for polishing an edge of a substrate

Abstract

Methods of and systems for polishing an edge of a substrate are provided. The invention includes rotating a substrate against a polishing film so as to remove material from the edge of the substrate; and detecting an amount of one of energy and torque exerted in rotating the substrate against the polishing film. The invention may further include determining an amount of material removed from the edge of the substrate based on the detected energy or torque exerted in rotating the substrate against the polishing film; ascertaining a difference between the determined amount of material removed and a preset polish level; and determining an amount of energy or torque to be exerted in rotating the substrate adapted to attain the preset polish level based on the difference between the determined amount of material removed and the preset polish level. Numerous other aspects are provided.

1 . A method of polishing an edge of a substrate comprising: 
 rotating a substrate against a polishing film so as to remove material from the edge of the substrate; and    detecting an amount of one of energy and torque exerted in rotating the substrate against the polishing film.    
   
   
       2 . The method of  claim 1 , further comprising: 
 determining an amount of material removed from the edge of the substrate based on the detected energy or torque exerted in rotating the substrate against the polishing film.    
   
   
       3 . The method of  claim 2 , further comprising: 
 ascertaining a difference between the determined amount of material removed and a preset polish level.    
   
   
       4 . The method of  claim 3 , further comprising: 
 determining an amount of energy or torque to be exerted in rotating the substrate adapted to attain the preset polish level based on the difference between the determined amount of material removed and the preset polish level.    
   
   
       5 . The method of  claim 4 , further comprising: 
 adjusting the amount of energy or torque exerted in rotating the substrate to the determined amount.    
   
   
       6 . The method of  claim 3 , further comprising: 
 ascertaining from the amount of material that has been removed from the substrate edge whether a layer of material has been removed.    
   
   
       7 . The method of  claim 1 , further comprising: 
 reducing friction between the substrate and the polishing film by delivering a fluid to the polishing film.    
   
   
       8 . The method of  claim 1 , further comprising: 
 removing particles from the edge of the substrate by delivering a fluid to the polishing film during contact with the substrate.    
   
   
       9 . A method of polishing an edge of a substrate comprising: 
 rotating a substrate against a polishing film so as to remove material from the edge of the substrate; and    detecting an amount of force exerted in pressing the polishing film against the substrate.    
   
   
       10 . The method of  claim 9 , further comprising: 
 determining an amount of material removed from the edge of the substrate based on the detected force exerted in pressing the polishing film against the rotating substrate.    
   
   
       11 . The method of  claim 10 , further comprising: 
 ascertaining a difference between the determined amount of material removed and a preset polish level.    
   
   
       12 . The method of  claim 11 , further comprising: 
 determining a level of force to be applied to the polishing film adapted to attain the preset polish level based on the difference between the determined amount of material removed and the preset polish level; and    adjusting the force to the determined level.    
   
   
       13 . A system adapted to polish an edge of a substrate comprising: 
 a substrate rotation driver adapted to rotate the edge of a substrate against a polishing film; and    a first sensor coupled to the rotation driver adapted to detect one of an energy and torque exerted by the substrate rotation driver as it rotates the substrate against the polishing film.    
   
   
       14 . The system of  claim 13 , further comprising: 
 a controller coupled to the first sensor and to the substrate rotation driver, adapted to receive from the first sensor a signal indicative of the detected energy or torque exerted by the substrate rotation driver and adapted to transmit control signals to the substrate rotation driver based on the detected energy or torque exerted.    
   
   
       15 . The system of  claim 14 , wherein the controller is adapted to determine an amount of material that has been removed from the substrate based on the received signal.  
   
   
       16 . The system of  claim 13 , further comprising: 
 an actuator adapted to press the polishing film against the rotating substrate.    
   
   
       17 . The system of  claim 16 , wherein the actuator is adapted to provide a signal indicative of a force exerted by the actuator in pressing the polishing film against the rotating substrate.  
   
   
       18 . The system of  claim 17 , wherein the controller is coupled to the actuator and is adapted to determine a force for the actuator to apply to the polishing film based on the signal provided by the actuator.  
   
   
       19 . The system of  claim 16 , wherein the actuator is adapted to press the polishing film against the rotating substrate for a period of time ranging from 15 to 150 seconds to obtain a preset level of polish.  
   
   
       20 . The system of  claim 18 , wherein the actuator is adapted to apply a force of about 0.5 pounds to 2.0 pounds to the polishing film to obtain a preset level of polish.  
   
   
       21 . The system of  claim 14 , further comprising: 
 a fluid supply coupled to the controller and to the polishing film;    wherein the controller is adapted to direct the fluid supply to deliver fluid onto the polishing film.    
   
   
       22 . The system of  claim 21 , wherein the fluid is supplied to a point of contact between the polishing film and the edge of the substrate.  
   
   
       23 . An apparatus adapted to apply a preset pressure to a polishing film in contact with an edge of a substrate comprising: 
 an actuator adapted to apply a preset pressure to the polishing film; and    a controller coupled to the actuator and adapted to receive a signal indicative of a condition of the edge of the substrate, and to adjust a pressure applied by the actuator to the polishing film so as to maintain the preset pressure based on the received signal.    
   
   
       24 . The apparatus of  claim 23 , wherein the signal indicates whether a layer of material has been removed from the edge of the substrate.  
   
   
       25 . The apparatus as recited in  claim 23 , further comprising: 
 a driver coupled to the controller adapted to rotate the substrate against the polishing film, the driver adapted to generate a signal indicative of the condition of the edge of the substrate.    
   
   
       26 . The apparatus of  claim 25 , wherein the controller is coupled to and adapted to direct operation of the driver in response to a signal received from the at least one sensor so as to attain a preset polish level.