Multi head pad conditioning apparatus and method of use

Abstract

Embodiments of the present disclosure provided herein include an apparatus and method for pad conditioning in a chemical mechanical polishing system. The apparatus includes a first conditioning head coupleable to a first pad conditioning disk disposed at a first head distance from the first conditioning head. The apparatus further includes a second a third conditioning head configured similarly to the first conditioning head. The apparatus includes a controller configured to receive sensor readings, determine whether the sensor readings are outside of a predetermined range, and adjust the first, second, and third head distances. A method of conditioning a polishing pad includes receiving sensor readings from at least one pad thickness sensor, determining if the sensor readings are outside of a predetermined range, and, upon determining that the sensor readings are outside of the predetermined range, adjusting a head distance of a conditioning head based on the sensor readings.

What is claimed is: 
     
         1 . A pad conditioning assembly, comprising:
 a base;   an arm coupled to the base;   a first conditioning head coupled to the arm and coupleable to a first pad conditioning disk disposed at a first head distance from the first conditioning head, the first conditioning head comprising a first linear actuator configured to adjust the first head distance;   a second conditioning head coupled to the arm and coupleable to a second conditioning disk disposed at a second head distance from the second conditioning head, the second conditioning head comprising a second linear actuator configured to adjust the second head distance;   a third conditioning head coupled to the arm and coupleable to a third conditioning disk disposed at a third head distance from the third conditioning head, the third conditioning head comprising a third linear actuator configured to adjust the third head distance;   a drive system coupled to the base and configured to drive rotation of the first conditioning head, the second conditioning head, and the third conditioning head; and   a controller configured to:
 rotate the arm into a starting position over a platen; 
 receive sensor readings; 
 determine whether the sensor readings are outside of a predetermined range; and 
 upon determining that the sensor readings are outside of the predetermined range, adjust the first head distance, the second head distance, the third head distance, or a combination thereof. 
   
     
     
         2 . The pad conditioning assembly of  claim 1 , further comprising at least one pad thickness sensor and wherein receiving sensor readings comprises receiving sensor readings corresponding to a thickness of a polishing pad from the at least one pad thickness sensor. 
     
     
         3 . The pad conditioning assembly of  claim 2 , wherein the sensor readings comprise initial sensor readings corresponding to a pad thickness of the polishing pad prior to undergoing a pad conditioning process. 
     
     
         4 . The pad conditioning assembly of  claim 3 , wherein adjusting the first head distance, the second head distance, the third head distance, or a combination thereof comprises adjusting each of the first head distance, the second head distance, and the third head distance based on the initial sensor readings from the at least one pad thickness sensor. 
     
     
         5 . The pad conditioning assembly of  claim 2 , wherein the sensor readings comprise in-process sensor readings corresponding to a pad thickness of the polishing pad undergoing a pad conditioning process. 
     
     
         6 . The pad conditioning assembly of  claim 5 , wherein adjusting the first head distance, the second head distance, the third head distance, or a combination thereof comprises adjusting each of the first head distance, the second head distance, and the third head distance based on the in-process sensor readings from the at least one pad thickness sensor. 
     
     
         7 . The pad conditioning assembly of  claim 2 ,
 wherein receiving sensor readings comprises receiving in-process sensor readings corresponding to a pad thickness of a polishing pad undergoing a pad conditioning process;   wherein adjusting the first head distance, the second head distance, the third head distance, or a combination thereof comprises adjusting each of the first head distance, the second head distance, and the third head distance based on the in-process sensor readings from the at least one pad thickness sensor; and   wherein the controller is further configured to, after adjusting the first head distance, the second head distance, the third head distance, or a combination thereof, receive subsequent in-process sensor readings corresponding to the pad thickness from the at least one pad thickness sensor.   
     
     
         8 . A method of conditioning a polishing pad, comprising:
 receiving sensor readings from at least one pad thickness sensor disposed on an arm of a pad conditioning assembly;   determining if the sensor readings are outside of a predetermined range; and   upon determining that the sensor readings are outside of the predetermined range, adjusting a first head distance of a first conditioning head, a second head distance of a second conditioning head, a third head distance of a third conditioning head, or a combination thereof, of the pad conditioning assembly based on the sensor readings.   
     
     
         9 . The method of  claim 8 , wherein the at least one pad thickness sensor comprises a first pad thickness sensor disposed near the first conditioning head, a second pad thickness sensor disposed near the second pad conditioning head, and a third pad thickness sensor disposed near the third pad conditioning head. 
     
     
         10 . The method of  claim 8 , wherein the sensor readings are initial sensor readings corresponding to a pad thickness of a polishing pad. 
     
     
         11 . The method of  claim 8 , wherein the predetermined range is a first predetermined range for initial sensor readings and a second predetermined range for in-process sensor readings, and wherein the first predetermined range and the second predetermined range are different. 
     
     
         12 . The method of  claim 8 , wherein the sensor readings are in-process sensor readings corresponding to a pad thickness of a polishing pad undergoing a pad conditioning process in the pad conditioning assembly. 
     
     
         13 . The method of  claim 8 , wherein the first head distance, the second head distance, and the third head distance are adjusted independently. 
     
     
         14 . The method of  claim 8 , further comprising, after adjusting the first head distance, the second head distance, the third head distance, or a combination thereof, receiving subsequent sensor readings from the at least one pad thickness sensor. 
     
     
         15 . A chemical mechanical polishing system, comprising:
 a polishing station comprising:
 a carrier head configured to hold a substrate; 
 a platen configured to hold a polishing pad; 
   a pad conditioning assembly comprising:
 a base; 
 an arm coupled to the base; 
 a first conditioning head coupled to the arm and coupleable to a first pad conditioning disk disposed at a first head distance from the first conditioning head, the first conditioning head comprising a first linear actuator configured to adjust the first head distance; 
 a second conditioning head coupled to the arm and coupleable to a second conditioning disk disposed at a second head distance from the second conditioning head, the second conditioning head comprising a second linear actuator configured to adjust the second head distance; 
 a third conditioning head coupled to the arm and coupleable to a third conditioning disk disposed at a third head distance from the third conditioning head, the third conditioning head comprising a third linear actuator configured to adjust the third head distance; 
 a drive system coupled to the base and configured to drive rotation of the first conditioning head, the second conditioning head, and the third conditioning head; 
 at least one pad thickness sensor and 
 a controller configured to:
 rotate the arm into a starting position over a platen; 
 receive sensor readings from the at least one pad thickness sensor; 
 determine whether the sensor readings are outside of a predetermined range; and 
 upon determining that the sensor readings are outside of the predetermined range, adjust the first head distance, the second head distance, the third head distance, or a combination thereof. 
 
   
     
     
         16 . The chemical mechanical polishing system of  claim 15 , wherein the sensor readings comprise initial sensor readings and in-process sensor readings, wherein the predetermined range comprises a first predetermined range for use with the initial sensor readings and a second predetermined range for use with the in-process sensor readings, and wherein the first predetermined range and the second predetermined range are different. 
     
     
         17 . The chemical mechanical polishing system of  claim 16 , wherein adjusting the first head distance, the second head distance, the third head distance, or a combination thereof comprises adjusting each of the first head distance, the second head distance, and the third head distance based on the initial sensor readings from the at least one pad thickness sensor. 
     
     
         18 . The chemical mechanical polishing system of  claim 16 , wherein adjusting the first head distance, the second head distance, the third head distance, or a combination thereof comprises adjusting each of the first head distance, the second head distance, and the third head distance based on the in-process sensor readings from the at least one pad thickness sensor. 
     
     
         19 . The chemical mechanical polishing system of  claim 15 , wherein the controller is further configured to receive subsequent sensor readings from the at least one pad thickness sensor after adjusting the first head distance, the second head distance, the third head distance, or a combination thereof. 
     
     
         20 . The chemical mechanical polishing system of  claim 15 ,
 wherein receiving sensor readings comprises receiving in-process sensor readings corresponding to a pad thickness of a polishing pad undergoing a pad conditioning process;   wherein adjusting the first head distance, the second head distance, the third head distance, or a combination thereof comprises adjusting each of the first head distance, the second head distance, and the third head distance based on the in-process sensor readings from the at least one pad thickness sensor; and   wherein the controller is further configured to, after adjusting the first head distance, the second head distance, the third head distance, or a combination thereof, receive subsequent in-process sensor readings corresponding to the pad thickness from the at least one pad thickness sensor.