Polishing apparatus and polishing method

Abstract

A polishing apparatus can supply a polishing liquid uniformly and efficiently to a surface to be polished of a workpiece. The polishing apparatus includes a polishing table having a polishing surface, and a top ring for holding a semiconductor wafer and pressing the semiconductor wafer against the polishing surface. The polishing apparatus also includes a polishing liquid supply port for supplying a polishing liquid to the polishing surface, and a moving mechanism for moving the polishing liquid supply port to distribute the polishing liquid uniformly over an entire surface of the workpiece due to relative movement of the workpiece and the polishing surface.

1 . A polishing apparatus comprising: 
 a polishing table having a polishing surface;    a top ring for holding a workpiece to be polished and pressing said workpiece against said polishing surface;    a polishing liquid supply port for supplying a polishing liquid to said polishing surface; and    a moving mechanism for moving said polishing liquid supply port to distribute said polishing liquid uniformly over an entire surface of said workpiece due to relative movement of said workpiece and said polishing surface.    
   
   
       2 . A polishing apparatus according to  claim 1 , wherein said moving mechanism makes said polishing liquid supply port move with at least one of a pivot motion, a reciprocating motion, a rotational motion, and a liner motion.  
   
   
       3 . A polishing apparatus according to  claim 1 , wherein said moving mechanism varies a moving speed of said polishing liquid supply port while the polishing liquid supply port is in motion.  
   
   
       4 . A polishing apparatus according to  claim 1 , further comprising: 
 a liquid rate control mechanism for controlling a rate of said polishing liquid supplied from said polishing liquid supply port while the polishing liquid supply port is in motion.    
   
   
       5 . A polishing apparatus according to  claim 1 , further comprising: 
 a polishing liquid supply nozzle having said polishing liquid supply port.    
   
   
       6 . A polishing apparatus according to  claim 1 , further comprising: 
 a polishing liquid supply nozzle having a plurality of said polishing liquid supply ports.    
   
   
       7 . A polishing apparatus according to  claim 6 , wherein said polishing liquid supply ports have different diameters.  
   
   
       8 . A polishing apparatus according to  claim 6 , further comprising: 
 a liquid rate control mechanism for individually controlling rates of said polishing liquid supplied from said polishing liquid supply ports.    
   
   
       9 . A polishing apparatus according to  claim 5 , wherein said polishing liquid supply nozzle extends in a radial direction of said polishing table.  
   
   
       10 . A polishing apparatus according to  claim 5 , wherein said polishing liquid supply nozzle is inclined a predetermined angle to a radial direction of said polishing table.  
   
   
       11 . A polishing apparatus comprising: 
 a polishing table having a polishing surface;    a top ring for holding a workpiece to be polished and pressing said workpiece against said polishing surface;    a plurality of polishing liquid supply ports for supplying a polishing liquid to said polishing surface; and    a liquid rate control mechanism for controlling rates of said polishing liquid supplied from said polishing liquid supply ports to distribute said polishing liquid uniformly over an entire surface of said workpiece due to relative movement of said workpiece and said polishing surface.    
   
   
       12 . A polishing apparatus according to  claim 11 , wherein said liquid rate control mechanism individually controls the rates of said polishing liquid supplied from said polishing liquid supply ports.  
   
   
       13 . A polishing apparatus according to  claim 11 , wherein said polishing liquid supply ports have different diameters.  
   
   
       14 . A polishing apparatus according to  claim 11 , further comprising: 
 a polishing liquid supply nozzle having said polishing liquid supply ports.    
   
   
       15 . A polishing apparatus according to  claim 14 , wherein said polishing liquid supply nozzle extends in a radial direction of said polishing table.  
   
   
       16 . A polishing apparatus according to  claim 14 , wherein said polishing liquid supply nozzle is inclined a predetermined angle to a radial direction of said polishing table.  
   
   
       17 . A polishing apparatus comprising: 
 a polishing table having a polishing surface;    a top ring for holding a workpiece to be polished and pressing said workpiece against said polishing surface;    a distributor for distributing and supplying a polishing liquid to said polishing surface; and    a polishing liquid supply port for supplying the polishing liquid to said distributor.    
   
   
       18 . A polishing apparatus according to  claim 17 , wherein said distributor comprises a fan-shaped distribution plate attached to said polishing liquid supply port.  
   
   
       19 . A polishing apparatus comprising: 
 a polishing table having a polishing surface;    a top ring for holding a workpiece to be polished and pressing said workpiece against said polishing surface;    a polishing liquid supply port for supplying a polishing liquid to said polishing surface; and    a distributor for distributing the polishing liquid supplied from said polishing liquid supply port and supplying the distributed polishing liquid between said workpiece and said polishing surface.    
   
   
       20 . A polishing apparatus according to  claim 19 , wherein said distributor comprises a disk-shaped distribution plate attached to said polishing liquid supply port.  
   
   
       21 . A polishing apparatus according to  claim 19 , wherein said distributor comprises a contact member disposed downstream of said polishing liquid supply port with respect to a direction in which said polishing surface moves and brought into contact with said polishing surface.  
   
   
       22 . A polishing apparatus according to  claim 21 , wherein said contact member is made of a wear-resistant elastic material.  
   
   
       23 . A polishing apparatus according to  claim 21 , wherein said contact member has a slit defined in an end thereof which comes into contact with said polishing surface.  
   
   
       24 . A polishing apparatus comprising: 
 a polishing table having a polishing surface; and    a top ring for holding a workpiece to be polished and pressing said workpiece against said polishing surface, said top ring having a retainer ring for holding an outer circumferential edge of said workpiece;    wherein said retainer ring has a groove defined in a surface which comes into contact with said polishing surface, said groove extending between outer and inner circumferential surfaces of said retainer ring; and    wherein said groove has an opening ratio ranging from 10% to 50% at the outer circumferential surface of said retainer ring.    
   
   
       25 . A polishing apparatus according to  claim 24 , wherein said top ring rotates at a rotational speed which is in the range of 1/3 to 1/1.5 of the rotational speed of said polishing table.  
   
   
       26 . A polishing apparatus according to  claim 25 , wherein said polishing table and said top ring rotate in one direction.  
   
   
       27 . A polishing apparatus according to  claim 25 , wherein said polishing table and said top ring rotate in opposite directions, respectively.  
   
   
       28 . A polishing apparatus according to  claim 24 , wherein said retainer ring comprises: 
 a presser for pressing said polishing surface to adjust a state of contact between said workpiece and said polishing surface; and    a guide for preventing said workpiece from being displaced from said top ring.    
   
   
       29 . A polishing apparatus according to  claim 28 , wherein said guide is positioned more closely to said workpiece than said presser.  
   
   
       30 . A polishing apparatus according to  claim 28 , wherein said guide is adapted to adjust a height from said polishing surface.  
   
   
       31 . A polishing apparatus according to  claim 28 , wherein said guide is of a ring shape.  
   
   
       32 . A polishing apparatus according to  claim 28 , wherein said guide has a radial width of at most 6 mm.  
   
   
       33 . A polishing apparatus according to  claim 28 , wherein said guide is made of a material that is less hard than an object to be polished.  
   
   
       34 . A polishing apparatus comprising: 
 a polishing table having a polishing surface;    a top ring for holding a workpiece to be polished and pressing said workpiece against said polishing surface;    a polishing liquid supply port for supplying a polishing liquid to said polishing surface; and    a relatively moving mechanism for moving said polishing surface and said workpiece relatively to each other at a relative speed of at least 2 m/s.;    wherein said polishing surface has a groove having a cross-sectional area of at least 0.38 mm 2 .    
   
   
       35 . A polishing apparatus according to  claim 34 , wherein said groove comprises a plurality of concentric grooves.  
   
   
       36 . A polishing apparatus according to  claim 35 , wherein said polishing surface has narrow slots interconnecting said grooves.  
   
   
       37 . A polishing apparatus according to  claim 36 , wherein said narrow slots comprise straight grooves inclined to a circumferential direction of said polishing table.  
   
   
       38 . A polishing apparatus according to  claim 34 , wherein said polishing surface has a plurality of holes defined therein and each having an opening area of at least 2.98 mm 2 .  
   
   
       39 . A polishing apparatus according to  claim 34 , wherein said polishing liquid supply port comprises a plurality of polishing liquid supply ports.  
   
   
       40 . A polishing apparatus comprising: 
 a polishing table having a polishing surface;    a top ring for holding a workpiece to be polished and pressing said workpiece against said polishing surface; and    a polishing liquid supply port for supplying a polishing liquid to said polishing surface;    wherein said polishing surface has a plurality of holes defined therein and each having an opening area of at least 2.98 mm 2 .    
   
   
       41 . A polishing apparatus according to  claim 40 , wherein each of said holes has an opening area of at least 19.63 mm 2 .  
   
   
       42 . A polishing apparatus comprising: 
 a polishing table having a polishing surface;    a plurality of polishing liquid supply ports for supplying a polishing liquid to said polishing surface; and    a plurality of polishing liquid supply lines extending respectively from said polishing liquid supply ports and adapted to be connected directly to a polishing liquid circulation system which is disposed outside of the polishing apparatus.    
   
   
       43 . A polishing apparatus comprising: 
 a polishing table having a polishing surface;    a top ring for holding a workpiece to be polished and pressing said workpiece against said polishing surface;    a fluid ejecting mechanism for ejecting a mixed fluid of a cleaning liquid and a gas to said polishing surface; and    a discharging mechanism for discharging said mixed fluid from said polishing surface, said discharging mechanism being disposed downstream of said fluid ejecting mechanism with respect to a direction in which said polishing surface moves.    
   
   
       44 . A polishing apparatus according to  claim 43 , wherein said discharging mechanism comprises a contact member for bringing into contact with said polishing surface.  
   
   
       45 . A polishing apparatus according to  claim 44 , wherein said contact member is made of a material having a low coefficient of friction.  
   
   
       46 . A polishing apparatus according to  claim 44 , wherein said contact member is made of a material having a high sealing capability.  
   
   
       47 . A polishing apparatus according to  claim 44 , wherein said contact member extends in a radial direction of said polishing table.  
   
   
       48 . A polishing apparatus according to  claim 44 , wherein said contact member is inclined a predetermined angle to a radial direction of said polishing table.  
   
   
       49 . A polishing apparatus according to  claim 43 , wherein said discharging mechanism comprises: 
 a gas ejection port for ejecting a gas to said polishing surface; and    a controller for controlling at least one of an amount of the gas ejected from said gas ejection port, a pressure of the gas ejected from said gas ejection port, and a direction of the gas ejected from said gas ejection port.    
   
   
       50 . A polishing apparatus according to  claim 49 , wherein said gas ejection port extends in a radial direction of said polishing table.  
   
   
       51 . A polishing apparatus according to  claim 49 , wherein said gas ejection port is inclined a predetermined angle to a radial direction of said polishing table.  
   
   
       52 . A polishing apparatus according to  claim 43 , further comprising: 
 a cover disposed in covering relation to said fluid ejecting mechanism and said discharging mechanism.    
   
   
       53 . A polishing apparatus according to  claim 43 , wherein said fluid ejecting mechanism and said discharging mechanism are disposed upstream of said top ring with respect to a direction in which said polishing surface moves.  
   
   
       54 . A polishing apparatus according to  claim 43 , further comprising: 
 a dresser for dressing said polishing surface.    
   
   
       55 . A method of polishing a workpiece by pressing the workpiece against a polishing surface of a polishing table and moving said polishing surface and said workpiece relatively to each other, comprising: 
 ejecting a mixed fluid of a cleaning liquid and a gas from a fluid ejecting mechanism to said polishing surface while the workpiece is being polished; and    discharging said mixed fluid from said polishing surface with a discharging mechanism which is disposed downstream of said fluid ejecting mechanism with respect to a direction in which said polishing surface moves.    
   
   
       56 . A method according to  claim 55 , further comprising: 
 dressing said polishing surface while the workpiece is being polished.    
   
   
       57 . A method of polishing a workpiece, comprising: 
 polishing the workpiece under a low pressure of at most 13.79 kPa; and then    polishing said workpiece under a low pressure of at most 13.79 kPa at a relative speed of at least 2 m/s. between said workpiece and said polishing surface while water is being supplied to said workpiece.    
   
   
       58 . A method of polishing a workpiece, comprising: 
 polishing the workpiece under a low pressure of at most 13.79 kPa; and then    polishing said workpiece under a low pressure of at most 13.79 kPa at a relative speed of at least 2 m/s. between said workpiece and said polishing surface while a chemical solution is being supplied to said workpiece.    
   
   
       59 . A method according to  claim 58 , wherein said chemical solution comprises a chemical solution for promoting separation of the polishing liquid attached to a surface of said workpiece.  
   
   
       60 . A method according to  claim 58 , wherein said chemical solution comprises a chemical solution including a citric acid.  
   
   
       61 . A method of polishing a workpiece, comprising: 
 polishing the workpiece to remove a substantial portion of a first film formed on the workpiece in a first-stage;    polishing the workpiece to remove a remaining portion of the first film until a second film on the workpiece is exposed in a second-stage, leaving an interconnects area;    presetting a film thickness distribution for the first film upon transition from said first-stage polishing to said second-stage polishing;    measuring a thickness of said first film with an eddy-current sensor in said first-stage polishing to acquire a film thickness distribution of said first film; and    adjusting polishing conditions in said second-stage polishing to equalize the acquired film thickness distribution of said first film to the preset film thickness distribution for the first film.    
   
   
       62 . A method according to  claim 61 , wherein said first-stage polishing is switched to said second-stage polishing when the acquired film thickness distribution of said first film is equalized to the preset film thickness distribution for the first film.  
   
   
       63 . A method of forming an interconnect on a substrate, comprising: 
 forming a flat conductive thin film on the substrate; and then    removing said flat conductive thin film from the substrate by a chemical etching process.    
   
   
       64 . A method according to  claim 63 , wherein forming a flat conductive thin film is performed by a chemical mechanical polishing process.  
   
   
       65 . A method according to  claim 63 , wherein forming a flat conductive thin film is performed by an electrolytic polishing process.  
   
   
       66 . A method according to  claim 65 , wherein said electrolytic polishing process comprises an electrolytic polishing process using an ion exchanger.  
   
   
       67 . A method according to  claim 63 , wherein said chemical etching process is performed with the use of an etchant comprising at least one of sulfuric acid, nitric acid, halogen acid, hydrogen peroxide, ammonia water, and a mixture thereof.  
   
   
       68 . A method according to  claim 63 , wherein a thickness of said conductive thin film is measured in said forming a flat conductive thin film, and said forming a flat conductive thin film is finished when the measured thickness reaches a predetermined thickness.  
   
   
       69 . A method according to  claim 68 , wherein said predetermined thickness is at most 100 nm.  
   
   
       70 . A method according to  claim 63 , wherein said conductive thin film contains at least one of Cu, Ta, TaN, WN, TiN, and Ru.