Polishing pad for a chemical mechanical planarization or polishing (CMP) system

Abstract

A polishing pad for a chemical mechanical planarization or polishing (CMP) system has a polish rate responsive to the pad contact area and the pad contact dynamics. The pad contact area is characterized by a predetermined statistical distribution. The pad contact dynamics are characterized by a mechanical behavior.

1 . A polishing pad for a chemical mechanical planarization (CMP) system, comprising: 
 a surface characterized by a polish rate responsive to a pad contact area and pad contact dynamics,    wherein the pad contact area is characterized by a predetermined statistical distribution of a pad surface height, and    wherein the pad contact dynamics are characterized by a mechanical behavior of the polishing pad.    
     
     
         2 . The polishing pad of  claim 1 , wherein the predetermined statistical distribution comprises a sum of a first statistical distribution and a second statistical distribution.  
     
     
         3 . The polishing pad of  claim 2 , wherein the first statistical distribution comprises a distribution based on a bulk component of the surface, and wherein the second statistical distribution comprises a distribution based on a near surface component of the surface.  
     
     
         4 . The polishing pad of  claim 2 , 
 wherein the first statistical distribution comprises an exponentially modified Gaussian distribution, and wherein the second statistical distribution comprises a Gaussian distribution.    
     
     
         5 . The polishing pad of  claim 1 , wherein the statistical distribution comprises at least one mathematical distribution selected from the group consisting of a Gaussian distribution, an exponentially modified Gaussian distribution, and a Pearson distribution.  
     
     
         6 . The polishing pad of  claim 1 , wherein the pad surface height comprises surface height characterized by a pad height histogram.  
     
     
         7 . The polishing pad of  claim 6 , wherein the pad surface height comprises a surface height responsive to a geometric average of a surface height data set.  
     
     
         8 . The polishing pad of  claim 1 , wherein the mechanical behavior comprises behavior responsive to a volumetric displacement of the polishing pad.  
     
     
         9 . The polishing pad of  claim 1 , wherein the mechanical behavior comprises behavior comprises behavior characterized as an elastic spring.  
     
     
         10 . The polishing pad of  claim 1 , wherein the mechanical behavior comprises behavior characterized by Hooke's Law.  
     
     
         11 . The polishing pad of  claim 1 , wherein the polish rate comprises a rate responsive to an optimal pad contact area.  
     
     
         12 . The polishing pad of  claim 11 , wherein the optimal pad contact area comprises about 0 percent to about 15 percent.  
     
     
         13 . The polishing pad of  claim 11 , wherein the optimal pad contact area comprises about 3 percent to about 8 percent.  
     
     
         14 . The polishing pad of  claim 11 , wherein the optimal pad contact area comprises about 6 percent.  
     
     
         15 . The polishing pad of  claim 11 , wherein the optimal pad contact area comprises an area that varies in response to at least one process parameter.  
     
     
         16 . The polishing pad of  claim 15 , wherein the at least one process parameter comprises a slurry, a wafer type, a platen speed, and a holder speed.  
     
     
         17 . The polishing pad of  claim 15 , wherein the at least one process parameter comprises at least one physical property of the polishing pad.  
     
     
         18 . The polishing pad of  claim 17 , wherein the at least one physical property comprises one or more of: 
 i. a density greater than about 0.5 g/cm.sup.3;    ii. a tensile modulus of about 0.02 to about 5 GigaPascals;    iii. a hardness of about 25 to about 80 Shore D;    vi. a yield stress of about 300 to about 6000 psi;    iv. a tensile strength of about 1000 to about 15,000 psi; and    v. an elongation to break up to about 500%.    
     
     
         19 . A polishing pad for a chemical mechanical planarization (CMP) system, comprising: 
 a surface characterized by a polish rate responsive to a predetermined statistical distribution of a pad surface height and a mechanical behavior of the polishing pad,    wherein the statistical distribution comprises a first statistical distribution and a second statistical distribution, the first statistical distribution representing a bulk component of the surface the second statistical distribution representing a near surface component of the surface, and    wherein the mechanical behavior is characterized by an elastic spring.    
     
     
         20 . The polishing pads of  claim 19 , 
 wherein the first statistical distribution comprises an exponentially modified Gaussian distribution, and wherein the second statistical distribution comprises a Gaussian distribution.    
     
     
         21 . The polishing pad of  claim 19 , wherein the statistical distribution comprises at least one mathematical distribution selected from the group consisting of a Gaussian distribution, an exponentially modified Gaussian distribution, and a Pearson distribution.  
     
     
         22 . The polishing pad of  claim 19 , wherein the polish rate comprises a rate responsive to an optimal pad contact area.  
     
     
         23 . The polishing pad of  claim 22 , wherein the optimal pad contact area comprises an area that varies in response to at least one process parameter.  
     
     
         24 . The polishing pad of  claim 19 , wherein the mechanical behavior comprises behavior characterized by Hooke's Law.  
     
     
         25 . A chemical mechanical planarization (CMP) system, comprising: 
 a polishing pad disposed on a platen;    a wafer mounted in a holder; and    a slurry disposed between the polishing pad and the wafer,    wherein the holder is operable to press the wafer against a surface of the polishing pad,    wherein the surface is characterized by a predetermined statistical distribution of a pad surface height and a mechanical behavior of the polishing pad, and    wherein the polishing pad has a polish rate responsive to the pad surface height distribution and the mechanical behavior.    
     
     
         26 . The CMP system of  claim 25 , wherein the statistical distribution comprises an exponentially modified Gaussian distribution and a Gaussian distribution.  
     
     
         27 . The CMP system of Caim  25 , wherein the mechanical behavior comprises behavior characterized by Hooke's Law.  
     
     
         28 . The CMP system of  claim 25 , wherein the polish rate comprises a rate responsive to an optimal pad contact area.  
     
     
         29 . The CMP system of  claim 28 , wherein the optimal pad contact area comprises about 0 percent to about 15 percent.  
     
     
         30 . The CMP system of  claim 25 , wherein the polishing pad comprises a thermoplastic material.  
     
     
         31 . The CMP system of  claim 30 , wherein the thermoplastic material comprises at least one moiety selected from the group consisting of a urethane; a carbonate; an amide; an ester; an ether; an acrylate; a methacrylate; an acrylic acid; a methacrylic acid; a sulphone; an acrylamide; a halide; and a hydroxide.  
     
     
         32 . The CMP system of  claim 25 , wherein the wafer comprises at least one of an oxide, a metal, a semiconductor, and an alloy.  
     
     
         33 . The CMP system of  claim 25 , wherein the wafer comprises at least one of Si, SiO 2 , GaAs, Cu, Ta, TaN, W, TiN, Ti, and Si 3 N 4 .  
     
     
         34 . The CMP system of  claim 25 , wherein the slurry comprises one of an alkaline-based solution and an acid-based solution.  
     
     
         35 . The CMP system of  claim 25 , wherein the slurry comprises colloidal silica.  
     
     
         36 . The CMP system of  claim 25  further comprising a pad conditioner disposed on the polishing pad, the pad conditioner operable to remove pad material from the polishing pad.  
     
     
         37 . The CMP system of  claim 36 , wherein the polish rate comprises a rate responsive to the removal of pad material by the pad conditioner.  
     
     
         38 . The CMP system of  claim 37 , wherein the polish rate comprises a rate characterized as rate-saturated conditioning.  
     
     
         39 . A polishing pad for a chemical mechanical planarization (CMP) system, comprising: 
 a surface characterized by a polish rate responsive to a pad contact area and pad contact dynamics,    wherein the pad contact area is characterized by a predetermined statistical distribution of a pad surface height, and    wherein the pad contact dynamics are characterized by a frictional loading factor and a pressure force.    
     
     
         40 . The polishing pad of  claim 39 , wherein the pressure force is characterized by the Sommerfeld number.  
     
     
         41 . The polishing pad of  claim 40 , wherein the Sommerfeld number ranges from about 0 to about 3.  
     
     
         42 . The polishing pad of  claim 39 , wherein the frictional loading factor is represented by the expression μV/P c , where P c  is an applied pressure by the polishing pad to a wafer divided by the pad contact area, V is a relative velocity between the wafer and the polishing pad, and μ is a slurry viscosity.  
     
     
         43 . The polishing pad of  claim 39 , wherein the pad contact area is responsive to pad conditioning of the surface by a pad conditioner.  
     
     
         44 . The polishing pad of  claim 43 , wherein the pad conditioner comprises a conditioner having diamond crystals with a spatial density ranging from about 1 per square millimeter to about 100 per square millimeter.  
     
     
         45 . The polishing pad of  claim 44 , wherein the diamond crystals comprise crystals having geometric configurations selected from the group consisting of angular, block, mosaic, and cubo-octahedral.  
     
     
         46 . The polishing pad of  claim 44 , wherein the diamond crystals have nominal diameters in the range of about 20 to about 500 μm.  
     
     
         47 . The polishing pad of  claim 43 , wherein the pad conditioner is characterized by a pad material removal rate of between about 0 to about 200 μm/hour.