Precise real time and position low pressure control of chemical mechanical polish (cmp) head

Abstract

A method and system for detecting and controller wafer surface pressure distribution. Detecting and controlling wafer surface pressure distribution comprises measuring in situ wafer uniformity of a wafer at a plurality of locations of the wafer; and in response to the measured wafer uniformity controlling through a feedback loop in situ CMP head pressure applied at the plurality of locations of the wafer in real time to polish the wafer.

1 . A method of detecting and controlling wafer surface pressure distribution, comprising:
 measuring in situ wafer uniformity of a wafer at a plurality of locations of the wafer; and   in response to the measured wafer uniformity controlling in situ CMP head pressure applied at the plurality of locations of the wafer in real time to polish the wafer.   
     
     
         2 . The method of  claim 1 , further comprising polishing the surface of the wafer at the plurality of locations using the controlled CMP head pressure. 
     
     
         3 . The method of  claim 1 , wherein controlling the in situ CMP head pressure applied comprises controlling an electrical pressure regulator. 
     
     
         4 . The method of  claim 3 , wherein the electrical pressure regulator is of a CMP system. 
     
     
         5 . The method of  claim 3 , wherein the electrical pressure regulator comprises a plurality of electrical pressure regulator elements corresponding to a plurality of CMP head pressure zones of a CMP system. 
     
     
         6 . The method of  claim 1 , wherein the plurality of locations comprise a plurality of surface locations of the wafer. 
     
     
         7 . The method of  claim 1 , wherein measuring the wafer uniformity comprises measuring wafer uniformity at the plurality of locations at a wafer surface of the wafer. 
     
     
         8 . The method of  claim 1 , wherein measuring the wafer uniformity comprises scanning surface uniformity of the wafer at the plurality of locations of the wafer. 
     
     
         9 . The method of  claim 8 , further comprising a Z-scanner scanning wafer thickness of the wafer at the plurality of locations of the wafer. 
     
     
         10 . The method of  claim 8 , further comprising a Z-scanner scanning wafer film hardness of the wafer at the plurality of locations of the wafer. 
     
     
         11 . The method of  claim 8 , further comprising a Z-scanner scanning pattern density of the wafer at the plurality of locations of the wafer. 
     
     
         12 . The method of  claim 1 , wherein a plurality of pressure regulators of a scanning device measuring wafer uniformity of the wafer at the plurality of locations of the wafer. 
     
     
         13 . The method of  claim 1 , wherein controlling the CMP head pressure comprises providing the measured wafer uniformity to a controller that controls in real time a plurality of CMP pressure regulators of the CMP head in response to the measured wafer uniformity. 
     
     
         14 . The method of  claim 1 , further comprising in response to the measured wafer uniformity controlling in situ CMP head pressure applied at the plurality of locations of the wafer in real time to polish the wafer by choosing a CMP head of a plurality of CMP heads having a desired low pressure profile. 
     
     
         15 . A method of detecting and controlling wafer surface pressure distribution, comprising:
 measuring in situ wafer uniformity of a wafer at a plurality of locations of the wafer;   determining from the measurements at the plurality of locations a uniformity wafer profile of the wafer;   determining whether the uniformity wafer profile approximates a target uniformity wafer profile of the wafer;   generating an updated uniformity wafer profile if the uniformity wafer profile does not approximate a target uniformity wafer profile of the wafer; and   in accordance with the updated uniformity wafer profile controlling in situ CMP head pressure applied by a plurality of CMP head pressure zones corresponding to the plurality of locations at the plurality of locations of the wafer in real time to polish the wafer.   
     
     
         16 . The method  claim 15 , wherein controlling in situ CMP head pressure applied by the plurality of CMP head pressure zones comprises controlling an electrical pressure regulator of a CMP system. 
     
     
         17 . The method of  claim 15 , wherein controlling in situ CMP head pressure applied by the plurality of CMP head pressure zones comprises controlling a plurality of electrical pressure regulator elements corresponding to the plurality of CMP head pressure zones of the CMP system. 
     
     
         18 . The method of  claim 15 , further comprising in accordance with the updated uniformity wafer profile controlling in situ CMP head pressure applied by a plurality of CMP head pressure zones corresponding to the plurality of locations at the plurality of locations of the wafer in real time to polish the wafer by choosing a CMP head of a plurality of CMP heads having a desired low pressure profile corresponding to the plurality of CMP head pressure zones. 
     
     
         19 . A method of detecting and controlling wafer surface pressure distribution, comprising:
 measuring in situ wafer uniformity of a wafer at a plurality of locations of the wafer;   adjusting in situ CMP head pressure of a plurality of CMP head pressure zones corresponding to the plurality of locations of the wafer in response to the measured wafer uniformity; and   polishing the wafer with the adjusted CMP head pressure at the plurality of locations.   
     
     
         20 . The method  claim 19 , wherein adjusting the in situ CMP head pressure of the plurality of CMP head pressure zones comprises controlling an electrical pressure regulator of a CMP system. 
     
     
         21 . The method of  claim 20 , wherein adjusting the in situ CMP head pressure of the plurality of CMP head pressure zones comprises controlling a plurality of electrical pressure regulator elements corresponding to the plurality of CMP head pressure zones of the CMP system. 
     
     
         22 . The method of  claim 19 , wherein polishing the wafer with the adjusted CMP head pressure further comprises choosing a CMP head of a plurality of CMP heads having a desired low pressure profile corresponding to the plurality of CMP head pressure zones. 
     
     
         23 . A chemical mechanical polish (CMP) system for polishing a wafer, comprising:
 a pressure controller;   a polishing head;   one or more pressure regulators coupled to the polishing head and controlled by the pressure controller;   wherein a measured wafer uniformity measured in situ of a wafer at a plurality of locations of the wafer at a first time is feedback to the pressure controller and the pressure controller in response to the measured wafer uniformity controls in situ CMP head pressure applied at the plurality of locations of the wafer in real time by the plurality of pressure regulators to polish the wafer in situ at a second time subsequent the first time.   
     
     
         24 . The system of  claim 23 , wherein the one or more pressure regulators comprise one or more electrical pressure regulators (EPRs). 
     
     
         25 . The system of  claim 23 , wherein the one or more electrical pressure regulators correspond to a plurality of CMP head pressure zones of the system. 
     
     
         26 . The system of  claim 23 , wherein the plurality of locations comprise a plurality of surface locations of the wafer. 
     
     
         27 . The system of  claim 23 , wherein the measured wafer uniformity is the measured at the plurality of locations at a wafer surface of the wafer. 
     
     
         28 . The system of  claim 27 , wherein the measured wafer uniformity is the wafer thickness of the wafer at the plurality of locations of the wafer. 
     
     
         29 . The system of  claim 27 , wherein the measured wafer uniformity is the wafer film hardness of the wafer at the plurality of locations of the wafer. 
     
     
         30 . The system of  claim 27 , wherein the measured wafer uniformity is the pattern density of the wafer at the plurality of locations of the wafer. 
     
     
         31 . The system of  claim 27 , wherein the measured wafer uniformity is the wafer film surface charge of the wafer at the plurality of locations of the wafer. 
     
     
         32 . The system of  claim 23 , wherein the pressure controller determines from the measured wafer uniformity a uniformity wafer profile of the wafer at the first time and if the uniformity wafer profile of the wafer does not approximate a target uniformity wafer profile of the wafer the pressure controller controls the one or more pressure regulators in accordance with an updated uniformity wafer profile generated by comparing the uniformity wafer profile to the target uniformity wafer profile. 
     
     
         33 . The system of  claim 32 , wherein in accordance with the updated uniformity wafer profile, the pressure controller controlling in situ CMP head pressure applied by a plurality of CMP head pressure zones of the one or more pressure regulators corresponding to the plurality of locations at the plurality of locations of the wafer in real time to polish the wafer.