Multi-zone carrier head for chemical mechanical polishing and cmp method thereof

Abstract

A multi-zone carrier head includes a housing; a retaining ring secured to a lower edge of the housing; a backing plate having a plurality of non-concentric pressure zones defined by a plurality of isolated apertures on the backing plate; wherein the backing plate has a wafer side and a non-wafer side, the wafer side facing a backside of a wafer during a CMP operation; and a plurality of pneumatic bladder for independently controlling pressure exerted in the respective non-concentric pressure zones on the backside of the wafer during the CMP operation.

1 . A multi-zone carrier head for chemical mechanical polishing (CMP), comprising: 
 a housing;    a retaining ring secured to a lower edge of the housing;    a backing plate having a plurality of non-concentric pressure zones defined by a plurality of isolated apertures on the backing plate; wherein the backing plate has a wafer side and a non-wafer side, the wafer side facing a backside of a wafer during a CMP operation;    a pneumatic means for independently controlling pressure exerted in the respective non-concentric pressure zones on the backside of the wafer during the CMP operation; and    a pressure-sensing element disposed under the pneumatic means in the respective non-concentric pressure zones.    
     
     
         2 . The multi-zone carrier head for CMP according to  claim 1 , further comprising a backing film attached to the wafer side of the backing plate, wherein the backing film is disposed between the backing plate and the backside of the wafer during the CMP operation.  
     
     
         3 . The multi-zone carrier head for CMP according to  claim 1 , wherein plurality of isolated apertures on the backing plate include a central aperture and peripheral apertures surrounding the central aperture.  
     
     
         4 . The multi-zone carrier head for CMP according to  claim 1 , wherein the multi-zone carrier head further comprises a diaphragm seal.  
     
     
         5 . The multi-zone carrier head for CMP according to  claim 4 , wherein the diaphragm seal is an annular ring of a flexible material.  
     
     
         6 . (canceled)  
     
     
         7 . The multi-zone carrier head for CMP according to  claim 1 , wherein the pressure-sensing element includes piezo-materials, piezo-crystals, piezo sensors or piezoelectric ceramic sensors.  
     
     
         8 . The multi-zone carrier head for CMP according to  claim 1 , wherein the pressure-sensing element is selected from the group consisting of BaTiO3, AIN, ZnO, lead zirconium titanate, PZT ceramic (PbZrTi), tantalum oxide (Ta205), and barium strontium tantanite (BST).  
     
     
         9 . The multi-zone carrier head for CMP according to  claim 1 , wherein the pressure-sensing element detects topography of the wafer during the CMP operation and transmits feedback signals to a control unit.  
     
     
         10 . A method for polishing a substrate, comprising: 
 mounting a substrate into a carrier head, the carrier head comprising a pneumatic means controlled by a control unit for independently controlling pressure exerted in respective non-concentric pressure zones on backside of the substrate and a pressure-sensing element under the pneumatic means in the respective non-concentric pressure zones;    respectively rotating the carrier head and a polishing pad on which the substrate is resting;    providing a down force on the substrate; and    polishing a material layer of the substrate away.    
     
     
         11 . (canceled)  
     
     
         12 . The method of  claim 10 , wherein the pressure-sensing element includes piezo-materials, piezo-crystals, piezo sensors or piezoelectric ceramic sensors.  
     
     
         13 . The method of  claim 10 , wherein the pressure-sensing element is selected from the group consisting of BaTiO3, AIN, ZnO, lead zirconium titanate, PZT ceramic (PbZrTi), tantalum oxide (Ta205), and barium strontium tantanite (BST).  
     
     
         14 . The method of  claim 10 , wherein the pressure-sensing element detects topography of the substrate during a CMP operation and transmits feedback signals to a control unit.