Method and apparatus for reciprocal polishing

Abstract

A polishing pad is located on a reciprocal motion generator. The polishing pad includes a plurality of discrete fluid channels. An abrasive article is located on the polishing pad. The abrasive article is reciprocally energized relative to the work piece. A fluid pressure in one or more of the discrete fluid channels is altered to selectively deform the abrasive article to preferentially remove material from the work piece.

1 . A polishing apparatus for polishing work pieces, the polishing apparatus comprising:
 a reciprocal motion generator;   a polishing pad located on the reciprocal motion generator, the polishing pad having a plurality of discrete fluid channels;   an abrasive article located on the polishing pad; and   a controller fluidly coupled to the discrete fluid channels and programmed to selectively alter a fluid pressure in one or more of the discrete fluid channels to selectively deform the abrasive article to preferentially remove material from the work piece.   
     
     
         2 . The polishing apparatus of  claim 1  wherein the fluid channels are configured in one of linear, curvilinear, or concentric pattern. 
     
     
         3 . The polishing apparatus of  claim 1  further comprising sensors adapted to monitor material removal from the work piece. 
     
     
         4 . The polishing apparatus of  claim 3  further comprising a closed-loop control system for polishing the work piece. 
     
     
         5 . The polishing apparatus of  claim 1  further comprising a gimbal assembly connecting the work piece bar to a support structure, the gimbal assembly applying a preload that biases the work piece toward the abrasive article. 
     
     
         6 . The polishing assembly of  claim 5  further comprising one or more actuators configured to alter the pitch and roll of the work piece relative to the abrasive article. 
     
     
         7 . The polishing apparatus of  claim 1  further comprising a hydrostatic bearing assembly including a plurality of ports fluidly coupled to a source of compress air, the ports oriented toward the abrasive article to maintain a hydrostatic air bearing between the work piece and the abrasive article. 
     
     
         8 . The polishing apparatus of  claim 1  wherein the abrasive article is one of flexible, rigid or semi-rigid. 
     
     
         9 . The polishing apparatus of  claim 1  wherein the fluid channels are configured to create a crown or camber on the work piece. 
     
     
         10 . A method of polishing a work piece comprising the steps of:
 locating a polishing pad on a reciprocal motion generator, the polishing pad including a plurality of discrete fluid channels;   locating an abrasive article on the polishing pad;   reciprocally energizing the abrasive article relative to the work piece; and   selectively altering a fluid pressure in one or more of the discrete fluid channels to selectively deform the abrasive article to preferentially remove material from the work piece.   
     
     
         11 . The method of  claim 10  further comprising configuring the fluid channels in one of a linear, a curvilinear, or a concentric pattern. 
     
     
         12 . The method of  claim 10  further comprising:
 monitoring sensors adapted to measure material removal from the work piece; and 
 altering the fluid pressure in one or more of the discrete fluid channels in response to a signal from the sensors. 
 
     
     
         13 . The method of  claim 12  further comprising controlling fluid pressure in the fluid channels in accordance with a closed-loop control system. 
     
     
         14 . The method of  claim 10  further comprising:
 supporting the work piece with a gimbal assembly; and 
 applying a preload to bias the work piece toward the abrasive article. 
 
     
     
         15 . The method of  claim 10  further comprising actuating one or more actuators to alter the pitch and roll of the work piece relative to the abrasive article. 
     
     
         16 . The method of  claim 10  further comprising creating a hydrostatic bearing between the work piece and the abrasive article. 
     
     
         17 . The method of  claim 10  further comprising the steps of delivering a compressed gas to a plurality of ports on a work piece holder to maintain a hydrostatic air bearing between the work piece and the abrasive article. 
     
     
         18 . The method of  claim 10  further comprising altering the pressure in one or more of the fluid channels to create a crown or camber on the work piece. 
     
     
         19 . The method of  claim 10  wherein the work piece comprises one of machined metal parts, silicon wafers, slider bars for hard disk drives, lenses, or optical fibers.