Methods and apparatus for indicating a polishing tape end

Abstract

Apparatus and methods are provided for polishing a substrate with a polishing tape. The polishing tape includes a first surface adapted to contact a substrate; and a second surface, wherein at least one of the first and second surfaces include a feature adapted to indicate an end condition. Numerous other aspects are provided.

1 . A polishing tape for polishing a substrate, the polishing tape comprising:
 a first surface adapted to contact a substrate; and   a second surface, and   wherein at least one of the first and second surfaces include a feature adapted to indicate an end condition.   
   
   
       2 . The polishing tape of  claim 1  wherein the first surface is abrasive and the second surface is non-abrasive. 
   
   
       3 . The polishing tape of  claim 2  wherein the feature is included in the second surface. 
   
   
       4 . The polishing tape of  claim 1  wherein the feature is optically different from a non-feature portion of the polishing tape. 
   
   
       5 . The polishing tape of  claim 4  wherein the optically different feature comprises at least one of thickness, texture and contrast. 
   
   
       6 . The polishing tape of  claim 4  wherein the optically different feature comprises a difference in absorption of light wavelengths compared to the non-feature portion of the polishing tape. 
   
   
       7 . The polishing tape of  claim 4  wherein the optically different feature comprises at least one of etchings and cut-outs. 
   
   
       8 . The polishing tape of  claim 2  further comprising an adhesive, wherein the adhesive is adapted to adhere the feature to the non-abrasive surface of the polishing tape. 
   
   
       9 . The polishing tape of  claim 1  further comprising at least two calibration features. 
   
   
       10 . The polishing tape of  claim 9  wherein the at least two calibration features are optically different from a non-feature portion of the polishing tape. 
   
   
       11 . A system for polishing a substrate comprising:
 a substrate support;   a polishing apparatus comprising:
 a housing including:
 at least one supply spool; and 
 at least one take-up spool; 
 
 a polishing tape, wherein the polishing tape is adapted to advance between the supply and take-up spools, wherein the polishing tape comprises:
 a first surface adapted to contact a substrate; 
 
 and
 a second surface, and 
 wherein at least one of the first and second surfaces include a feature adapted to indicate an end condition of the polishing tape; and 
 
   a controller adapted to determine the end condition of the polishing tape based on the feature.   
   
   
       12 . The system of  claim 11  wherein the first surface is abrasive and the second surface is non-abrasive. 
   
   
       13 . The system of  claim 12  further comprising:
 a sensor, wherein the sensor is adapted to detect the feature.   
   
   
       14 . The system of  claim 13  wherein the controller is adapted to receive a signal from the sensor indicative of the detected feature. 
   
   
       15 . The system of  claim 14  wherein the controller is adapted to determine the end condition based on the signal. 
   
   
       16 . The system of  claim 12  wherein the feature is optically different from a non-feature portion of the polishing tape. 
   
   
       17 . The system of  claim 16  wherein the optically different feature comprises at least one of texture and contrast. 
   
   
       18 . The system of  claim 16  wherein the optically different feature comprises a difference in absorption of light wavelengths compared to the non-feature portion of the polishing tape. 
   
   
       19 . The system of  claim 11  wherein the polishing tape further comprises at least two calibration features. 
   
   
       20 . The system of  claim 19  wherein the at least two calibration features are optically different from a non-feature portion of the polishing tape. 
   
   
       21 . The system of  claim 20  further comprising one or more motor encoders adapted to regulate the speed of at least one of the supply and take-up spools. 
   
   
       22 . The system of  claim 21  wherein the controller is adapted to calibrate the one or more motor encoders based on the at least two calibration features. 
   
   
       23 . A method for determining a polishing tape end condition comprising:
 advancing a polishing tape from a supply spool to a take-up spool;   detecting a feature on a portion of the polishing tape; and   determining the feature is a polishing tape end condition.   
   
   
       24 . The method of  claim 23  wherein detecting the feature further comprises:
 comparing the feature portion of the polishing tape to a non-feature portion of the polishing tape.   
   
   
       25 . The method of  claim 23  further comprising:
 detecting a calibration feature on a portion of the polishing tape; and   calibrating a motor encoder based on the detection of the calibration feature.