Polishing apparatus

Abstract

A polishing apparatus for polishing a workpiece by utilizing a fluid including abrasive particles having a dielectric property. The polishing apparatus includes an electrode for applying processing pressure to the abrasive particles on the workpiece and having electrode elements for collecting and arranging the abrasive particles by a Coulomb force produced by application of an alternating-current voltage to the electrode, and a driving device for driving the electrode.

1 . A polishing apparatus for polishing a workpiece by utilizing a fluid including abrasive particles having a dielectric property, comprising: 
 an electrode configured to apply processing pressure to the abrasive particles on the workpiece and having a plurality of electrode elements configured to collect and arrange the abrasive particles by a Coulomb force produced by application of an alternating-current voltage to the electrode; and    a driving device for driving the electrode.    
     
     
         2 . A polishing apparatus according to  claim 1 , wherein the plurality of electrode elements are cylindrical, having different diameters and disposed in a concentric circular formation and mutually separated by insulative material.  
     
     
         3 . A polishing apparatus according to  claim 1 , wherein different voltages are applied to the plurality of electrode elements.  
     
     
         4 . A polishing apparatus according to  claim 2 , wherein different voltages are applied to the plurality of electrode elements.  
     
     
         5 . A polishing apparatus according to  claim 2 , wherein the plurality of electrode elements include inner and outer electrode elements, and a lower voltage is applied to the inner electrode elements and a higher voltage is applied to the outer electrode elements.  
     
     
         6 . A polishing apparatus according to  claim 3 , wherein the plurality of electrode elements include inner and outer electrode elements, and a lower voltage is applied to the inner electrode elements and a higher voltage is applied to the outer electrode elements.  
     
     
         7 . A polishing apparatus according to  claim 4 , wherein the plurality of electrode elements include inner and outer electrode elements, and a lower voltage is applied to the inner electrode elements and a higher voltage is applied to the outer electrode elements.  
     
     
         8 . A polishing apparatus according to  claim 1 , wherein the electrode comprises a cylindrical electrode having a film-shaped conductor and an insulative layer that are wound around a spindle so that the conductor and insulative layer are alternated around the spindle.  
     
     
         9 . A polishing apparatus according  claim 1 , further comprising an insulative tube positioned to supply a fluid containing a dispersion of said abrasive particles to the workpiece and electrodes provided around the insulative tube to adjust fluid flow from the insulative tube.  
     
     
         10 . A polishing apparatus according to  claim 2 , further comprising an insulative tube positioned to supply a fluid containing a dispersion of said abrasive particles to the workpiece and electrodes provided around the insulative tube to adjust fluid flow from the insulative tube.  
     
     
         11 . A polishing apparatus according to  claim 3 , further comprising an insulative tube positioned to supply a fluid containing a dispersion of said abrasive particles to the workpiece and electrodes provided around the insulative tube to adjust fluid flow from the insulative tube.  
     
     
         12 . A polishing apparatus according to  claim 4 , further comprising an insulative tube positioned to supply a fluid containing a dispersion of said abrasive particles to the workpiece and electrodes provided around the insulative tube to adjust fluid flow from the insulative tube.  
     
     
         13 . A polishing apparatus according to  claim 5 , further comprising an insulative tube positioned to supply a fluid containing a dispersion of said abrasive particles to the workpiece and electrodes provided around the insulative tube to adjust fluid flow from the insulative tube.  
     
     
         14 . A polishing apparatus according to  claim 6 , further comprising an insulative tube positioned to supply a fluid containing a dispersion of said abrasive particles to the workpiece and electrodes provided around the insulative tube to adjust fluid flow from the insulative tube.  
     
     
         15 . A polishing apparatus according to  claim 7 , further comprising an insulative tube positioned to supply a fluid containing a dispersion of said abrasive particles to the workpiece and electrodes provided around the insulative tube to adjust fluid flow from the insulative tube.  
     
     
         16 . A polishing apparatus according to  claim 8 , further comprising an insulative tube positioned to supply a fluid containing a dispersion of said abrasive particles to the workpiece and electrodes provided around the insulative tube to adjust fluid flow from the insulative tube.  
     
     
         17 . A method of polishing a workpiece comprising: 
 supplying a fluid including abrasive particles having a dielectric property to the workpiece;    providing an electrode configured to apply processing pressure to the abrasive particles on the workpiece and having a plurality of electrode elements configured to collect the abrasive particles; and    applying an alternating-current voltage to the electrode to produce a Coulomb force.    
     
     
         18 . A method according to  claim 17 , wherein said providing includes providing the plurality of electrode elements which are cylindrical having different diameters and disposed in a concentric circular formation and mutually separated by insulative material.  
     
     
         19 . A method according to  claim 17 , wherein said applying includes applying different voltages to the plurality of electrode elements.  
     
     
         20 . A method according to  claim 18 , wherein the plurality of electrode elements include inner and outer electrode elements, and said applying includes applying a lower voltage to the inner electrode elements and applying a higher voltage to the outer electrode elements.  
     
     
         21 . A method according to  claim 17 , wherein said providing includes providing a cylindrical electrode having a film-shaped conductor and an insulative layer by winding the film-shaped conductor and the insulative layer around a spindle alternately.  
     
     
         22 . A method according to  claim 17 , further comprising: 
 providing an insulative tube configured to supply a fluid containing a dispersion of the abrasive particles to the workpiece; and    providing electrodes around the insulative tube to adjust fluid flow from the insulative tube.