Patent Publication Number: US-11648638-B2

Title: Substrate polishing apparatus and polishing liquid discharge method in substrate polishing apparatus

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This patent application is the U.S. national phase of International Application No. PCT/JP2018/030613, filed Aug. 20, 2018, which claims the benefit of Japanese Patent Application No. 2017-158473, filed on Aug. 21, 2017, which are incorporated by reference in their entireties herein. 
     TECHNICAL FIELD 
     The present invention relates to a substrate polishing apparatus and a polishing liquid discharge method in the substrate polishing apparatus. 
     BACKGROUND ART 
     As one type of the substrate polishing apparatus used in a semiconductor processing operation, there has been a Chemical Mechanical Polishing (CMP) apparatus. In a typical CMP apparatus, a polishing pad is installed to a rotary table (platen), and a substrate is installed to a polishing head. The CMP apparatus rotates each of the rotary table and the polishing head while pressing the substrate to the polishing pad from above, thereby polishing the substrate. Usually, the polishing pad is supplied with a polishing liquid during the polishing of the substrate. A common polishing liquid for the CMP apparatus contains abrasive grains of SiO 2 , Al 2 O 3 , and the like. 
     As one of methods for supplying the polishing liquid, there is a method to supply the polishing liquid from a lower portion of the table. Japanese Unexamined Patent Application Publication No. 2008-110471 (PTL 1) discloses a substrate polishing apparatus where a turntable includes a polishing liquid discharge port. In the substrate polishing apparatus disclosed in PTL 1, the polishing liquid is supplied via a rotary joint disposed downward the turntable. 
     CITATION LIST 
     Patent Literature 
     PTL 1: Japanese Unexamined Patent Application Publication No. 2008-110471 
     SUMMARY OF INVENTION 
     Technical Problem 
     In the device disclosed in PTL 1, the polishing liquid internally passes through the rotary joint. Therefore, components inside the rotary joint are possibly degenerated due to a chemical reaction with the polishing liquid, and in addition, the components inside the rotary joint are possibly abraded by abrasive grains contained in the polishing liquid. The degeneration and/or the abrasion of the components of the rotary joint not only possibly makes the supply of the polishing liquid unstable, but also possibly causes leakage of the polishing liquid. Accordingly, in the device disclosed in PTL 1, maintenance of the rotary joint is preferably performed regularly. However, for the maintenance, a material cost, labor costs, and the like for replacing the component are required. Since the operation of the device needs to be stopped during the maintenance work, the maintenance possibly decreases work efficiency of the device. 
     There is also a polishing liquid for the CMP apparatus that does not contain the abrasive grains (abrasive grainless polishing liquid). In this case, it is considered that the abrasion of the component due to the abrasive grains is not caused. However, even in the case of using the abrasive grainless polishing liquid, the degeneration of the component due to the reaction with the polishing liquid is possibly caused. 
     Accordingly, it is an object of this application to provide a substrate polishing apparatus and a polishing liquid discharge method in the substrate polishing apparatus to solve at least a part of the above-described problems. 
     Solution to Problem 
     This application discloses a substrate polishing apparatus as one embodiment. The substrate polishing apparatus includes: a polishing head for holding a substrate; a rotary table that has a surface to which a first opening portion is provided; a polishing liquid discharge mechanism disposed to the rotary table; and a controller configured to control at least the polishing liquid discharge mechanism. The polishing liquid discharge mechanism includes a first cylinder, a first piston, and a driving mechanism that drives the first piston. The first opening portion is communicated with a liquid holding space defined by the first cylinder and the first piston. The controller controls the driving of the first piston by the driving mechanism to increase and decrease a volume of the liquid holding space. 
     Furthermore, this application discloses a polishing liquid discharge method in a substrate polishing apparatus as one embodiment. The polishing liquid discharge method includes: a step of preparing a rotary table that includes a cylinder and a piston and has a surface to which an opening portion is provided for discharging a polishing liquid; a step of communicating with a liquid holding space and filling the polishing liquid in the liquid holding space from the opening portion, the liquid holding space being defined by the cylinder and the piston; and a step of discharging the polishing liquid from the opening portion by driving the piston to press the polishing liquid filled in the liquid holding space. 
     The substrate polishing apparatus and the polishing liquid discharge method in the substrate polishing apparatus provide an exemplary effect that the product life of the rotary joint can be extended because the polishing liquid does not pass through the rotary joint. 
     Furthermore, this application discloses the substrate polishing apparatus that includes a polishing liquid filling mechanism for filling a polishing liquid in the liquid holding space via the first opening portion as one embodiment. 
     The substrate polishing apparatus provides an exemplary effect that the polishing liquid can be filled in the liquid holding space. 
     Furthermore, this application discloses the substrate polishing apparatus where the driving mechanism includes a driving fluid supply mechanism that drives the first piston by a pressure of a driving fluid as one embodiment. Furthermore, this application discloses the substrate polishing apparatus where the driving mechanism includes a second cylinder and a second piston connected to the first piston, and the driving fluid supply mechanism is configured to drive the second piston by the pressure of the driving fluid to indirectly drive the first piston as one embodiment. Furthermore, this application discloses the substrate polishing apparatus where the driving fluid is a gas or a liquid as one embodiment. Furthermore, this application discloses the substrate polishing apparatus that includes a biasing mechanism that biases the first piston in an opposite direction of a direction in which the first piston is driven when the pressure of the driving fluid is increased as one embodiment. Furthermore, this application discloses the substrate polishing apparatus where the biasing mechanism is a spring as one embodiment. Furthermore, this application discloses the substrate polishing apparatus where the driving mechanism includes an electric driving mechanism as one embodiment. 
     The disclosure describes the driving mechanism in detail. 
     Furthermore, this application discloses the substrate polishing apparatus where the driving fluid is a gas or a liquid, the substrate polishing apparatus further includes a head up-and-down motion mechanism for pressing the substrate toward the rotary table, a second opening portion provided to the surface of the rotary table, a driving fluid supply line that communicates the driving fluid supply mechanism with the second opening portion, and a valve disposed on the driving fluid supply line, the valve being controlled by the controller, and the controller controls the valve to discharge the driving fluid from the second opening portion when the head up-and-down motion mechanism moves the polishing head upward as one embodiment. 
     The substrate polishing apparatus provides an exemplary effect that removal of the substrate from the polishing pad is facilitated. 
     Furthermore, this application discloses the substrate polishing apparatus that includes a sensor that measures a flow rate of the driving fluid or the pressure of the driving fluid, and the controller controls the driving mechanism based on a measurement value of the sensor as one embodiment. 
     The substrate polishing apparatus provides an exemplary effect that the discharge of the liquid can be precisely controlled. 
     Furthermore, this application discloses the substrate polishing apparatus that includes a rotary joint connected to the driving mechanism, and a power is supplied to the driving mechanism Via the rotary joint as one embodiment. 
     The disclosure describes the power supply in detail. Note that, since the power of the driving mechanism is, for example, a pneumatic, a hydraulic, or an electric power, abrasion of the rotary joint can be reduced. 
     Furthermore, this application discloses the substrate polishing apparatus where the polishing liquid discharge mechanism includes a cleaning liquid supply port communicated with the liquid holding space, the substrate polishing apparatus further includes a cleaning liquid supply line connected to the cleaning liquid supply port, the cleaning liquid supply line supplies a cleaning liquid to the liquid holding space passing through the cleaning liquid supply port, and the cleaning liquid is supplied from a cleaning liquid supply source as one embodiment. 
     The substrate polishing apparatus provides an exemplary effect that the holding and the discharge of the cleaning liquid by the polishing liquid discharge mechanism ensures the cleaning of the polishing pad, the substrate, and/or the liquid holding space. 
     Furthermore, this application discloses the substrate polishing apparatus where the rotary table is provided with a plurality of the first opening portions communicated with the identical liquid holding space as one embodiment. Furthermore, this application discloses the substrate polishing apparatus where a plurality of the polishing liquid discharge mechanisms are disposed as one embodiment. 
     These substrate polishing apparatus provide an exemplary effect that disposing a plurality of opening portions and/or polishing liquid discharge mechanisms ensures adjustment of the discharge of the liquid. 
     Furthermore, this application discloses the substrate polishing apparatus that further includes a storage configured to store a liquid discharge pattern, and the controller controls the driving mechanism based on the liquid discharge pattern as one embodiment. 
     The substrate polishing apparatus provides an exemplary effect that the liquid can be discharged based on a desired pattern. 
     Furthermore, this application discloses the polishing liquid discharge method where the step of filling the polishing liquid in the liquid holding space includes a step of supplying the polishing liquid to the opening portion from a position opposing the rotary table, and a step of driving the piston to increase a volume of the liquid holding space after the step of supplying the polishing liquid or in at least a part of a period in the step of supplying the polishing liquid as one embodiment. 
     The liquid filling method provides an exemplary effect that the filling of the liquid in the liquid holding space is facilitated even when the opening portion has a small diameter. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG.  1 A  is a top view of a substrate polishing apparatus that includes a polishing liquid discharge mechanism. 
         FIG.  1 B  is a front view of the substrate polishing apparatus that includes the polishing liquid discharge mechanism. 
         FIG.  2    is a front cross-sectional view of the polishing liquid discharge mechanism and a driving mechanism. 
         FIG.  3    is a front cross-sectional view illustrating the polishing liquid discharge mechanism and the driving mechanism using a magnet. 
         FIG.  4    is a front cross-sectional view of the polishing liquid discharge mechanism and the driving mechanism independent of the polishing liquid discharge mechanism. 
         FIG.  5    is a front cross-sectional view of the polishing liquid discharge mechanism and an electric driving mechanism. 
         FIG.  6 A  is a front cross-sectional view of the substrate polishing apparatus before a polishing liquid is filled. 
         FIG.  6 B  is a front cross-sectional view of the substrate polishing apparatus during the filling of the polishing liquid. 
         FIG.  6 C  is a front cross-sectional view of the substrate polishing apparatus after the filling of the polishing liquid. 
         FIG.  6 D  is a front cross-sectional view of the substrate polishing apparatus during discharge of the polishing liquid. 
         FIG.  7 A  is a front cross-sectional view of a substrate polishing apparatus that includes a rotary table where three first opening portions communicated with an identical liquid holding space are provided. 
         FIG.  7 B  is a front cross-sectional view of the substrate polishing apparatus that includes the rotary table where the three first opening portions communicated with the identical liquid holding space are provided. 
         FIG.  8    is a front cross-sectional view of a substrate polishing apparatus that includes a plurality of polishing liquid discharge mechanisms. 
         FIG.  9 A  is a top view of a rotary table where five first opening portions are provided. 
         FIG.  9 B  is a top view of the rotary table where the five first opening portions are provided. 
         FIG.  9 C  is a top view of the rotary table where the five first opening portions are provided. 
         FIG.  10 A  is a top view of the rotary table and a polygonal substrate. 
         FIG.  10 B  is a top view of the rotary table and the polygonal substrate. 
         FIG.  10 C  is a top view of the rotary table and the polygonal substrate. 
         FIG.  10 D  is a top view of the rotary table and the polygonal substrate. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     First Embodiment 
       FIG.  1 A  is a top view of a substrate polishing apparatus  10  according to the first embodiment, and  FIG.  1 B  is a front view.  FIG.  1    and other drawings are drawings schematically illustrating components of the substrate polishing apparatus  10 . Shapes, arrangements, sizes, and the like of the components in the respective drawings do not necessarily match with the shapes and the like of the actual device. 
     The substrate polishing apparatus  10  is a device that rotates both a rotary table  100  and a polishing head  110  while pressing a substrate  112  to a polishing pad  102 , thereby polishing the substrate  112 . Note that in the following description, a description will be given having a direction (downward direction on paper of  FIG.  1 B ) in which the substrate  112  is pressed as a “downward direction” and its opposite direction as an “upward direction.” However, the “upward direction” and the “downward direction” in this specification do not necessarily match a “vertically upward direction” and a “vertically downward direction.” For example, when the entire substrate polishing apparatus  10  is installed to be inclined, the “upward direction” and the “downward direction” become the directions corresponding to the inclination of the substrate polishing apparatus  10 . 
     (Rotary Table and Polishing Head) 
     The substrate polishing apparatus  10  includes the rotary table  100  rotated around a table rotation shaft  101  and a table rotation mechanism  103  that rotates the rotary table  100 . To a top surface of the rotary table  100 , the polishing pad  102  is replaceably installed. The substrate polishing apparatus  10  includes a controller  20  to control each component of the device, and a storage  30  to store conditions and the like for the control by the controller  20 . 
     The substrate polishing apparatus  10  further includes the polishing head  110  and a head rotation mechanism  113  that rotates the polishing head  110  around a head rotation shaft  111 . The polishing head  110  is disposed to be opposed to the rotary table  100 , and the polishing head  110  has a bottom surface to which the substrate  112  is replaceably installed. In the example of  FIG.  1   , the center of rotation of the rotary table  100  does not match the center of rotation of the polishing head  110 . However, the substrate polishing apparatus  10  may be configured so as to match the center of rotation of the rotary table  100  with the center of rotation of the polishing head  110 . The substrate polishing apparatus  10  further includes a head up-and-down motion mechanism  114  that moves the polishing head  110  up and down. When polishing the substrate  112 , the head up-and-down motion mechanism  114  moves the polishing head  110  to a lower portion, and presses the substrate  112  to the polishing pad  102 . In other words, the head up-and-down motion mechanism  114  presses the substrate  112  toward the rotary table  100 . When the polishing of the substrate  112  terminates, the head up-and-down motion mechanism  114  moves the polishing head  110  upward. The polished substrate is removed from the polishing head  110  at a retracted position (not illustrated) of the head, and a substrate to be polished next is handed over to the polishing head  110 . 
     (First Opening Portion) 
     In an ordinary substrate polishing apparatus, a polishing liquid is supplied to a polishing pad from a nozzle disposed upward the polishing pad during the polishing of the substrate. However, in this method, the polishing liquid cannot be directly supplied to a part of the polishing pad in contact with the substrate (part where the polishing head is present). Accordingly, it is often difficult to uniformly supply the polishing liquid to an interface between the substrate and the polishing pad. The ordinary substrate polishing apparatus is often configured such that the polishing liquid is supplied to the center of the polishing pad, that is, a position close to the table rotation shaft, and the polishing liquid near the center of the polishing pad spreads on the polishing pad toward a peripheral portion by a centrifugal force. However, because of recent up-sizing of the substrate, the substrate covers the top of the table rotation shaft, and the polishing liquid cannot be supplied to the position close to the table rotation shaft in some cases (see  FIG.  1   ). Not only in the case of supplying the polishing liquid, but also in a case of supplying a cleaning liquid, such as a pure water and a chemical liquid, to clean the substrate, similar problems exist. 
     Therefore, in this embodiment, the rotary table  100  includes a first opening portion  104 . In the example of  FIG.  1   , the first opening portion  104  is provided in the center of the rotary table  100 . Furthermore, a position of the polishing pad  102  corresponding to the first opening portion  104  when the polishing pad  102  is installed to the rotary table  100  is cut out. By discharging a liquid, such as the polishing liquid or the cleaning liquid, from the lower portion of the rotary table  100  via the first opening portion  104 , those liquids can be supplied to also the part of the polishing pad  102  in contact with the substrate  112 . 
     (Polishing Liquid Discharge Mechanism and Driving Mechanism) 
     To the lower portion of the rotary table  100 , a polishing liquid discharge mechanism  120  that holds the polishing liquid to be discharged from the first opening portion  104  and is rotated with the rotary table  100  is disposed. The polishing liquid discharge mechanism  120  includes a cylinder  121  and a piston  122 . The cylinder  121  and the piston  122  define a liquid holding space  123  to hold the liquid, such as the polishing liquid. The liquid holding space  123  is communicated with the first opening portion  104 , and by increasing and decreasing a volume of the liquid holding space  123 , the liquid can be discharged from the liquid holding space  123  via the first opening portion  104  and the liquid can be filled in the liquid holding space  123  via the first opening portion  104 . The liquid holding space  123  is configured to form a sealed space excluding that the liquid holding space  123  is communicated with the first opening portion  104 . Note that the term “cylinder” in this specification means a member or a portion configured to internally hold a fluid and has any shape. The cylinder  121  may be a member integrated with the rotary table  100 . For example, a depressed portion is formed on the lower surface of the rotary table  100 , and the depressed portion can be used as the cylinder  121 . Conversely, the cylinder  121  may be a member independent of the rotary table  100 . 
     The substrate polishing apparatus  10  further includes a driving mechanism  130  that drives the piston  122  to increase and decrease the volume of the liquid holding space  123 . In the example of  FIG.  1   , the polishing liquid discharge mechanism  120  and the driving mechanism  130  are integrally configured. 
     As the driving mechanism  130 , a mechanism that drives the piston  122  by a pressure of a driving fluid, typified by an air pressure system, a water pressure system, an oil pressure system, and the like, can be used. As the driving mechanism  130 , an electric driving mechanism can be used. In the example of  FIG.  1   , the driving mechanism  130  is a mechanism that uses a driving fluid. 
     (Power Supply to Driving Mechanism) 
     The power of the driving mechanism  130  is supplied via a supply passage  141  of a rotary joint  140 . The rotary joint  140  is disposed to a lower portion of the polishing liquid discharge mechanism  120 . The power of the driving mechanism  130  is the driving fluid (gas, water, an oil, or the like) when the driving mechanism  130  uses the driving fluid, and is an electric power when the driving mechanism  130  is the electric driving mechanism. 
     In the example of  FIG.  1   , the driving mechanism  130  uses the driving fluid. Therefore, the driving mechanism  130  includes a driving fluid supply mechanism  131  that supplies the driving fluid. When the driving fluid supplied to the driving mechanism  130  needs to be discharged, the discharge is performed via a discharge passage  142  connected to the rotary joint  140 . To control the supply and the discharge of the driving fluid, a valve  40  can be disposed to at least one of the supply passages  141  and the discharge passage  142 . When the valve  40  is an electrically-operated valve, the valve  40  may be connected to the controller  20 . When the electric driving mechanism is used as the driving mechanism  130 , a power source connected to the electric driving mechanism may be disposed instead of the driving fluid supply mechanism  131 . 
     Note that when a fluid cylinder, a battery, or the like are disposed to the rotary table  100 , it is not necessary to dispose the rotary joint  140 . 
     (Details of Polishing Liquid Discharge Mechanism and Driving Mechanism) 
     The polishing liquid discharge mechanism  120  and the driving mechanism  130  will be described in detail by referring to  FIGS.  2 ,  3 ,  4 , and  5   .  FIG.  2    is a front cross-sectional view of the polishing liquid discharge mechanism  120  and the driving mechanism  130 . In the example of  FIG.  2   , the first cylinder  121  internally includes the first piston  122  movable up and down. A gap between the first cylinder  121  and the first piston  122  is sealed by an O-ring  200 . That is, for the liquid holding space  123 , the first piston  122  moves up and down, thereby increasing and decreasing the volume of the liquid holding space  123 . 
     In the example of  FIG.  2   , the driving mechanism  130  uses the driving fluid. The driving mechanism  130  in the example of  FIG.  2    includes a second cylinder  201  and a second piston  202  disposed inside the second cylinder to be movable up and down. However, in this example, the first cylinder  121  and the second cylinder  201  are integrally formed, and the first piston  122  and the second piston  202  are integrally formed. In other words, the second piston  202  is connected to the first piston  122 . A gap between the second cylinder  201  and the second piston  202  is sealed by the O-ring  200 . The driving mechanism  130  includes a bottom plate  203 , and the second piston  202  and the bottom plate  203  define a fluid entering space  204 . To the fluid entering space  204 , the driving fluid supply mechanism  131  is connected via the rotary joint  140 . Furthermore, the driving mechanism  130  may include a biasing mechanism that biases the first piston in an opposite direction of a direction in which the first piston  122  is driven when the pressure of the driving fluid is increased. In the example of  FIG.  2   , a spring  205  is used as the biasing mechanism. In the example of  FIG.  2   , the first piston  122  is driven upward when the pressure of the driving fluid is increased. Therefore, the spring  205  is configured to press the second piston  202  downward to bias the first piston  122  integrally formed with the second piston  202  downward. 
     The second piston  202  is driven to a position where a force of the driving fluid, which is supplied to the fluid entering space  204  by the driving fluid supply mechanism  131 , to press up the second piston  202  is balanced with a force of the spring  205  to press down the second piston  202 . Accordingly, by increasing and decreasing the pressure of the driving fluid, the second piston  202  can be moved up and down. Since the second piston  202  is integrally formed with the first piston  122 , the first piston  122  can be driven by the pressure of the driving fluid. In other words, the driving fluid supply mechanism  131  is configured to drive the second piston  202  to indirectly drive the first piston  122 . 
     As the biasing mechanism, instead of the spring  205  illustrated in  FIG.  2   , a structure to press down the second piston  202  by a magnetic force can be employed.  FIG.  3    is a front cross-sectional view illustrating the polishing liquid discharge mechanism  120  and the driving mechanism  130  using a magnet (ferromagnet). In the example of  FIG.  3   , a first piston and a second piston are integrally formed, and there is no clear boundary between the first piston and the second piston. Therefore, in the description of the example of  FIG.  3   , the first piston and the second piston are collectively referred to as a “piston  122 .” In the example of  FIG.  3   , a first magnet  301  is disposed to a lower portion of the piston  122 . Furthermore, a depressed portion  302  is provided to a part of a top surface of the bottom plate  203 , and a second magnet  303  is disposed to the depressed portion  302 . In the example of  FIG.  3   , a magnetic pole of the first magnet  301  and a magnetic pole of the second magnet  303  are oriented so as to generate a magnetic attractive force between the first magnet  301  and the second magnet  303 . 
     In the example of  FIG.  3   , the piston  122  is driven to a position where a force of the driving fluid to press up the piston  122  is balanced with a force of the attractive force between the first magnet  301  and the second magnet  303  to press down the piston  122 . According to this configuration, the piston  122  can be driven without using the spring  205  illustrated in  FIG.  2   . 
     Here, the closer the distance between the first magnet  301  and the second magnet  303  becomes, the stronger the magnetic attractive force generated between them becomes. Therefore, when the first magnet  301  contacts the second magnet  303 , the magnetic attractive force becomes excessively strong, and the pressure of the driving fluid possibly fails to press up the piston  122 . In the example of  FIG.  3   , since the second magnet  303  is disposed to the depressed portion  302 , the first magnet  301  does not contact the second magnet  303  even if the piston  122  is moved to the lowest position. That is, by disposing the second magnet  303  to the depressed portion  302 , the generation of the excessively strong magnetic attractive force can be avoided. 
     The first magnet  301  and the second magnet  303  may be permanent magnets, or may be electromagnets. The material of the first piston  122  may be a magnetic material to use the piston  122  as the first magnet  301 . Conversely, the material of the bottom plate  203  may be a magnetic material to use the bottom plate  203  as the second magnet  303 . A configuration where a magnetic repulsion force is used to press down the piston  122  can be employed. 
     Different from  FIG.  2   , the polishing liquid discharge mechanism  120  and the driving mechanism  130  can be separately configured.  FIG.  4    is a front cross-sectional view of the polishing liquid discharge mechanism  120  and the driving mechanism  130  independent of the polishing liquid discharge mechanism. In this example, the first cylinder  121  and the second cylinder  201  are separately formed, and the first piston  122  and the second piston  202  are separately formed. However, the first piston  122  is connected to the second piston  202 , and the first piston  122  moves up and down in accordance with the up-and-down motion of the second piston  202 . The behaviors of the polishing liquid discharge mechanism  120  and the driving mechanism  130  of  FIG.  4    are identical to the behaviors of the polishing liquid discharge mechanism  120  and the driving mechanism  130  illustrated in  FIG.  2   . 
     The substrate polishing apparatus  10  that uses an electric driving mechanism  500  as the driving mechanism  130  will be described by referring to  FIG.  5   .  FIG.  5    is a front cross-sectional view of the polishing liquid discharge mechanism  120  and the electric driving mechanism  500 . To the piston  122  of the polishing liquid discharge mechanism  120  of FIG.  5 , at least one (in this example, two) electric driving mechanism  500  is secured. Furthermore, to the cylinder  121  of the polishing liquid discharge mechanism  120  of  FIG.  5   , at least one (in this example, two) guide  501  is secured. The electric driving mechanism  500  can move up and down along the guide  501 . The piston  122  moves up and down in accordance with the up-and-down motion of the electric driving mechanism  500 . The power (electric power) of the electric driving mechanism  500  is supplied from a power source  502  via the rotary joint  140 . While the electric driving mechanism  500  possibly has a complicated configuration compared with the driving mechanism (see  FIG.  2   ,  FIG.  3   , and  FIG.  4   ) using the driving fluid, the electric driving mechanism  500  provides an advantage that the electrical control can be performed is provided. 
     (Effect of Polishing Liquid Discharge Mechanism  120 ) 
     According to the above-described configuration, the polishing liquid is held in the liquid holding space  123  of the polishing liquid discharge mechanism  120 , and the polishing liquid does not pass through inside the rotary joint  140 . Therefore, the degeneration or the abrasion of the components of the rotary joint  140  due to the polishing liquid is not caused. Accordingly, the substrate polishing apparatus  10  according to the embodiment can extend the product life of the rotary joint  140  to reduce maintenance frequency of the rotary joint  140 . However, in addition to the configuration of the embodiment, a rotary joint through which the polishing liquid internally passes may be further disposed. Note that the rotary joint  140  of the embodiment can internally include the driving fluid or wiring. However, it is considered that the degeneration or the abrasion of the components of the rotary joint  140  due to the driving fluid or the wiring is significantly small compared with the degeneration or the abrasion due to the polishing liquid. 
     (Sensor) 
     The substrate polishing apparatus  10  of  FIG.  1    includes a sensor  132  to control the behavior of the driving mechanism  130 . In the example of  FIG.  1   , the sensor  132  is a flowmeter that measures a flow rate of the driving fluid supplied from the driving fluid supply mechanism  131 , and is installed to the supply passage  141 . As the sensor  132 , a pressure gauge that measures the pressure of the driving fluid can be used. Furthermore, when the driving mechanism  130  is the electric driving mechanism  500 , an encoder to measure a movement amount of the electric driving mechanism  500  can be employed as the sensor  132 . 
     The sensor  132  is connected to the controller  20 . With the control performed by the controller  20  based on the measurement value of the sensor  132 , the driving mechanism  130  can be precisely driven. In other words, with the control based on the measurement value of the sensor  132 , the discharge of the liquid from the polishing liquid discharge mechanism  120  can be precisely controlled. When the pressure gauge to measure the pressure of the driving fluid is used as the sensor  132 , the pressure of a space between the piston  202  and the bottom plate  203  can be detected. When the leakage of the fluid from the portion sealed by the O-ring  200  occurs due to a scratch and the like generated on the O-ring  200  and/or an abutting surface of the O-ring  200 , since the pressure of the space between the piston  202  and the bottom plate  203  changes, an abnormality in the sealed portion also can be detected by the sensor  132 . Also when the flowmeter is used as the sensor  132 , the abnormality in the sealed portion can be detected. These abnormality detections in the sealed portion are performed by the controller  20  (control device). 
     (Polishing Liquid Filling Mechanism) 
     The substrate polishing apparatus  10  of  FIG.  1    includes a polishing liquid filling mechanism  160  that fills the polishing liquid in the liquid holding space  123 . In the example of  FIG.  1   , the polishing liquid filling mechanism  160  includes an arm  161  and a nozzle  162 . The arm  161  is rotatably configured, and by rotating the arm  161 , the nozzle  162  can be positioned above the first opening portion  104  of the polishing pad  102 . However, the configuration of the polishing liquid filling mechanism  160  is not limited to the configuration illustrated in  FIG.  1   , and conventionally known any configuration, for example, a configuration where the arm  161  expands and contracts, can be employed. 
     A method for filling the polishing liquid in the liquid holding space  123  using the polishing liquid filling mechanism  160  will be described by referring to  FIG.  6   . Note that in  FIG.  6   , illustrations of the components other than the components necessary for describing the method for filling the polishing liquid are omitted in some cases. In  FIG.  6   , the polishing liquid discharge mechanism  120  and the driving mechanism  130  illustrated in  FIG.  2    are used.  FIG.  6 A  is a front cross-sectional view of the substrate polishing apparatus  10  before the polishing liquid is filled, that is, in a state where the piston  122  is completely elevated and the volume of the liquid holding space  123  becomes the lower limit. In this state, the liquid holding space  123  does not hold the polishing liquid at all (or hardly holds the polishing liquid). Accordingly, the polishing liquid needs to be filled in the liquid holding space  123 . 
     Therefore, the controller  20  controls the polishing liquid filling mechanism  160  to position the nozzle  162  of the polishing liquid filling mechanism  160  above the first opening portion  104 , that is, a position opposing the rotary table, thereby supplying the polishing liquid from the nozzle  162 .  FIG.  6 B  is a front cross-sectional view of the substrate polishing apparatus  10  during the filling of a polishing liquid  600 . As illustrated in  FIG.  6 B , the controller  20  controls the driving mechanism  130  to move the piston  122  downward, thereby increasing the volume of the liquid holding space  123 . 
     When the first opening portion  104  has a small diameter, only by supplying the polishing liquid onto the top of the first opening portion  104 , the polishing liquid hardly passes through the first opening portion  104 . As illustrated in  FIG.  6 B , by moving the piston  122  downward, the volume of the liquid holding space  123  increases and the polishing liquid is drawn into the liquid holding space  123 . Accordingly, the substrate polishing apparatus  10  according to the embodiment facilitates the filling of the polishing liquid  600  in the liquid holding space  123  even when the first opening portion  104  has the small diameter. The control of the driving mechanism  130  is performed after the supply of the polishing liquid  600  or at least a part of the period during the supply of the polishing liquid  600 . 
       FIG.  6 C  is a front cross-sectional view of the substrate polishing apparatus  10  after the filling of the polishing liquid  600 . As illustrated in  FIG.  6 C , the controller  20  stops the driving of the driving mechanism  130  when the volume of the liquid holding space  123  becomes maximum. Note that the driving of the driving mechanism  130  may be stopped when the polishing liquid  600  is filled by a predetermined amount. By the above-described steps, the liquid holding space  123  is filled with the polishing liquid  600 . 
     The filled polishing liquid  600  is discharged from the first opening portion  104  as necessary, for example, when the substrate is polished.  FIG.  6 D  is a front cross-sectional view of the substrate polishing apparatus  10  during the discharge of the polishing liquid  600 . As illustrated in  FIG.  6 D , the discharge of the polishing liquid  600  is performed by increasing the pressure of the driving fluid inside the fluid entering space  204 , driving the piston  122  upward, and pressing the polishing liquid  600 . By gradually increasing the pressure of the driving fluid, the polishing liquid  600  can be continuously discharged. 
     Note that the polishing liquid filling mechanism  160  may be configured to supply a liquid other than the polishing liquid. In this case, the liquid other than the polishing liquid can be filled in the liquid holding space  123 . The polishing liquid filling mechanism  160  can be used not only for filling the liquid, but also for supplying a liquid, such as the polishing liquid, to the polishing pad  102  during the polishing of the substrate  112 . 
     (Cleaning Liquid Supply Port and Cleaning Liquid Supply Source) 
     After the termination of the polishing of the substrate  112  in the substrate polishing apparatus  10 , to remove process scrap and the like accumulated on the polishing pad  102  and/or the substrate  112 , the polishing pad  102  and/or the substrate  112  is cleaned with a cleaning liquid in some cases. Since the cleaning liquid, such as a pure water and a chemical liquid, has a small degree of deterioration in the rotary joint compared with that of the polishing liquid, the cleaning liquid may be supplied to opening portions (not illustrated) provided to a supply line (not illustrated) and the polishing table directly from the rotary joint by passing the cleaning liquid through the rotary joint. 
     Alternatively, to discharge the cleaning liquid from the first opening portion  104 , the polishing liquid discharge mechanism  120  and other components may be configured to hold not only the polishing liquid but also the cleaning liquid. When the cleaning liquid can be supplied from the above-described polishing liquid filling mechanism  160 , the cleaning liquid can be filled in the polishing liquid discharge mechanism  120  from the polishing liquid filling mechanism  160 . However, when the first opening portion  104  is covered with the substrate  112 , it is difficult to fill the cleaning liquid using the polishing liquid filling mechanism  160 . 
     The liquid holding space  123  of the polishing liquid discharge mechanism  120  is communicated with the first opening portion  104 . Therefore, the process scrap generated on the polishing pad  102  possibly enters the liquid holding space  123 . Furthermore, when the kind of the liquid held in the liquid holding space  123  is changed, mixing the liquids before and after the change is to be avoided. Accordingly, for removing the process scrap or avoiding the mixture of the liquids, a mechanism configured to clean the liquid holding space  123  is preferably disposed. 
     Then, in the example of  FIG.  1   , a cleaning liquid supply port  124  communicated with the liquid holding space  123  is disposed on a side portion of the cylinder  121  in the polishing liquid discharge mechanism  120 . The cleaning liquid supply port  124  may be disposed so as to penetrate the piston  122  from the bottom portion to the top. Furthermore, the substrate polishing apparatus  10  of the embodiment includes a cleaning liquid supply source  150  connected to the cleaning liquid supply port  124  via the rotary joint  140 . In the example of  FIG.  1   , a cleaning liquid supply line  151  connected to the cleaning liquid supply port  124  is disposed, and the cleaning liquid supply line  151  supplies the cleaning liquid supplied from the cleaning liquid supply source  150  to the liquid holding space  123  passing through the cleaning liquid supply port  124 . Note that in the example of  FIG.  1   , the valve  40  is disposed between the cleaning liquid supply source  150  and the cleaning liquid supply port  124  (that is, on the cleaning liquid supply line  151 ). A sensor (not illustrated) to measure the flow rate or the pressure of the cleaning liquid may be disposed between the cleaning liquid supply source  150  and the cleaning liquid supply port  124 . 
     With this configuration, filling the cleaning liquid in the liquid holding space  123  is facilitated. The filled cleaning liquid may be used for cleaning the polishing pad  102  and/or the substrate  112 , and may be used for cleaning the liquid holding space  123 . The cleaning of the polishing pad  102  is performed by discharging the cleaning liquid from the first opening portion  104 . At this time, when the substrate  112  is in contact with the polishing pad  102 , the substrate  112  is cleaned together with the polishing pad  102 . Note that the discharge of the cleaning liquid from the first opening portion  104  can be performed by the pressure of the cleaning liquid supply source. Therefore, while the up-and-down motion of the piston  122  is not required, the up-and-down motion of the piston  122  may be performed for cleaning the liquid holding space  123 . The cleaning of the polishing pad  102  and/or the substrate  112  and the cleaning of the liquid holding space  123  by the cleaning liquid may be performed in parallel, or may be performed independently. 
     (Second Opening Portion) 
     After termination of the polishing of the substrate  112 , to remove the substrate  112  installed to the polishing head  110 , the head up-and-down motion mechanism  114  lifts the polishing head  110  and the substrate  112 . Here, the substrate  112  sticks to the polishing pad  102  to make difficult to remove the substrate  112  from the polishing pad  102  in some cases. 
     Therefore, in the example of  FIG.  1   , the rotary table  100  includes a second opening portion  105 . The driving fluid supply mechanism  131  is communicated with the second opening portion  105  by a driving fluid supply line  133 , and the driving fluid can be discharged to the top of the rotary table  100 . Note that the driving fluid supply line  133  includes the valve  40 . The controller  20  controls the head up-and-down motion mechanism  114 , the driving fluid supply mechanism  131 , and the valve  40  connected to the second opening portion  105  to move the polishing head  110  to upward while discharging the driving fluid from the second opening portion  105 . With this control, an upward force is applied to the substrate  112  by the driving fluid, thus facilitating the removal of the substrate  112  from the polishing pad  102 . When the driving mechanism  130  is the air pressure system or the water pressure system (when the driving fluid is a gas or a liquid), contamination of the substrate  112  due to the driving fluid is a little, and therefore, the configuration that includes the second opening portion  105  is especially advantageous. 
     Second Embodiment 
     The substrate polishing apparatus  10  of the first embodiment includes one first opening portion  104  in the center of the rotary table  100 . With this configuration, it is difficult to precisely adjust a distribution of the polishing liquid and the like on the polishing pad  102  in some cases. Therefore, a substrate polishing apparatus  10  according to the second embodiment includes a plurality of first opening portions  104  at the rotary table  100 . 
     The configuration of the plurality of first opening portions  104  will be described by referring to  FIGS.  7 ,  8 , and  9   . Note that in  FIGS.  7 ,  8 , and  9   , illustrations of the components other than the components necessary for describing the plurality of first opening portions  104  are omitted in some cases. 
       FIG.  7 A  is a front cross-sectional view of the substrate polishing apparatus  10  that includes a rotary table  100  where a plurality of (in this example, three) first opening portions  104 A,  104 B, and  104 C communicated with an identical liquid holding space  123  are provided. The first opening portions  104 A,  104 B, and  104 C each include an independent flow passage. By adjusting positions, flow passage diameters, flow passage lengths, and the like of the respective first opening portions, the discharge of the polishing liquid can be adjusted. The configuration of  FIG.  7 A  is advantageous in that the substrate polishing apparatus  10  of the first embodiment does not need to be significantly changed. Note that it is not necessary that the flow passages of the first opening portions  104 A,  104 B, and  104 C are completely independent. As illustrated in  FIG.  7 B , the flow passages of the first opening portions may each have a common part. 
       FIG.  8    is a front cross-sectional view of the substrate polishing apparatus  10  that includes a plurality of (in this example, two) polishing liquid discharge mechanisms  120 A and  120 B. The polishing liquid discharge mechanism  120 A is disposed in the center of the rotary table  100 , and the polishing liquid discharge mechanism  120 B is disposed at a position apart from the center of the rotary table  100 . The rotary table  100  includes a first opening portion  104 D so as to be communicated with a liquid holding space  123 A, and includes a first opening portion  104 E so as to be communicated with a liquid holding space  123 B. To the polishing liquid discharge mechanisms  120 A and  120 B, driving mechanisms  130 A and  130 B are connected, respectively. Since the driving mechanisms  130 A and  130 B are each independently driven, driving fluid supply mechanisms  131 A and  131 B are disposed. In this method, while the configuration is complicated, it is advantageous in that the polishing liquid discharge mechanisms  120 A and  120 B can be independently controlled. The driving mechanisms  130 A and  130 B may use one driving fluid supply mechanism  131  in common. When the polishing liquid discharge mechanism  120 A and the polishing liquid discharge mechanism  120 B hold the identical polishing liquid to supply, for example, the arm  161  may include a plurality of nozzles  162  to fill the polishing liquid in the liquid holding spaces in a state where the plurality of nozzles are each positioned above the corresponding first opening portion. 
     The polishing liquid discharge mechanisms  120 A and  120 B may each hold a different type of liquid. In the example of  FIG.  8   , the polishing liquid discharge mechanism  120 A is a mechanism that holds the polishing liquid and discharges the polishing liquid by the elevation of the piston. When the cleaning of the liquid holding space is not necessary, or when the cleaning of the liquid holding space can be performed by other means, the polishing liquid discharge mechanism  120 A does not need to include the cleaning liquid supply port  124 . However, the polishing liquid discharge mechanism  120 A may include the cleaning liquid supply port  124 . Meanwhile, in the example of  FIG.  8   , the polishing liquid discharge mechanism  120 B is a mechanism that holds the cleaning liquid and discharges the cleaning liquid by the elevation of the piston. Therefore, the polishing liquid discharge mechanism  120 B includes the cleaning liquid supply port  124  connected to the cleaning liquid supply source  150 . The configuration whose example is illustrated in  FIG.  8    ensures the precise control corresponding to the type of the liquid. 
       FIG.  9    includes top views of the rotary table  100  where a plurality of (in this example, five) first opening portions  104 F,  104 G,  10411 ,  1041 , and  104 J are provided. As illustrated in  FIG.  9 A , the first opening portions  104 F to  104 J may be arranged axially symmetric on a straight line passing through the center of the rotary table  100 . As illustrated in  FIG.  9 B , the first opening portions  104 F to  104 J may be arranged in one direction having the center of the rotary table  100  as a starting point on the straight line passing through the center of the rotary table  100 . Furthermore, as illustrated in  FIG.  9 C , the first opening portions  104 F to  104 J may be arranged on a concentric circle viewed from the center of the rotary table  100 . In addition, any number of first opening portions  104  can be disposed at any positions depending on a desired performance. 
     Third Embodiment 
     Constant discharge of the liquid, such as the polishing liquid, from the first opening portion  104  provided to the rotary table  100  possibly increases consumption quantity of the liquid. In the polishing liquid discharge mechanism  120  described above, since the volume of the liquid holding space  123  is limited, consumption quantity of the liquid is preferably reduced. Therefore, a controller  20  of a substrate polishing apparatus  10  of the third embodiment performs a control where the volume of a liquid holding space  123  is decreased by a driving mechanism  130  when the substrate  112  covers the first opening portion  104 , and the driving of the driving mechanism  130  is stopped when the substrate  112  does not cover the first opening portion  104 . 
     This embodiment will be described by referring to  FIG.  10   .  FIG.  10    includes top views of the rotary table  100  and the substrate  112 . In the example of  FIG.  10   , the substrate  112  has a polygonal shape. The configuration of the substrate polishing apparatus  10  in the example of  FIG.  10    is identical to the configuration of  FIG.  8   . That is, the rotary table  100  includes two first opening portions  104 D and  104 E, and polishing liquid discharge mechanisms  120 A and  120 B are disposed at lower portions of the respective first opening portions. In the example of  FIG.  10   , the rotary table  100  and the polishing head  110  (not illustrated in  FIG.  10   ) each rotate at an identical rotation speed in an identical direction.  FIGS.  10 B,  10 C, and  10 D  are top views of the rotary table  100  and the substrate  112  at time points where the rotary table  100  and the polishing head  110  are each rotated counterclockwise from the state of  FIG.  10 A  by 45 degrees, 90 degrees, and 135 degrees. 
     At the time point of  FIG.  10 A , both the first opening portion  104 D and the first opening portion  104 E are not covered with the substrate  112 . Therefore, the controller  20  performs the control to stop the driving of the driving mechanism  130 A and the driving mechanism  130 B to avoid the discharge of the liquid from the first opening portion  104 D and the first opening portion  104 E. 
     At the time point of  FIG.  10 B , the first opening portion  104 D is covered with the substrate  112 , but the first opening portion  104 E is not covered with the substrate  112 . Therefore, the controller  20  performs the control of the driving mechanism  130 A to decrease the volume of the liquid holding space  123 A of the polishing liquid discharge mechanism  120 A disposed at the lower portion of the first opening portion  104 D. Meanwhile, the driving mechanism  130 B is controlled not to be driven. Thus, the liquid is discharged from the first opening portion  104 D, but the liquid is not discharged from the first opening portion  104 E. 
     At the time point of  FIG.  10 C , similarly to  FIG.  10 A , both the first opening portion  104 D and the first opening portion  104 E are not covered with the substrate  112 . Therefore, the controller  20  performs the control to stop the driving of the driving mechanism  130 A and the driving mechanism  130 B. 
     At the time point of  FIG.  10 D , both the first opening portion  104 D and the first opening portion  104 E are covered with the substrate  112 . Therefore, the controller  20  performs the control of the driving mechanism  130 A and the driving mechanism  130 B to decrease the volumes of both the liquid holding spaces  123 A and  123 B. Thus, the liquid is discharged from both the first opening portion  104 D and the first opening portion  104 E. 
     With the above-described control, since the liquid is discharged from the first opening portion only when the first opening portion  104  is covered with the substrate  112 , the consumption quantity of the liquid can be reduced. The controller  20  may control the discharge of the liquid from each first opening portion depending on the rotation speeds of the rotary table  100  and the polishing pad  102 , the number and the position of the first opening portion  104 , the shape and the position of the substrate  112 , and the like. Whether the first opening portion  104  is covered with the substrate  112  or not can be determined by a not illustrated sensor (for example, optical sensor or pressure-sensitive sensor). Whether the first opening portion  104  is covered with the substrate  112  or not can be calculated from, for example, the rotation speeds of the rotary table  100  and the polishing pad  102 , the number and the position of the first opening portion  104 , the shape and the position of the substrate  112 , and the like. In this case, the storage  30  may store a liquid discharge pattern derived from the calculation result. The controller  20  reads the liquid discharge pattern from the storage  30  to ensure the control of the driving mechanism  130  based on the liquid discharge pattern. 
     The liquid discharge pattern can be determined in consideration of not only whether the first opening portion  104  is covered with the substrate  112  or not, but also other elements. For example, when a polishing amount increases only at the edge portion of the substrate  112 , the controller  20  may control the driving mechanism  130  so as to decrease the supply amount of the polishing liquid when the first opening portion  104  is covered with the edge portion of the substrate  112 . Meanwhile, when the substrate  112  has a part where the polishing is insufficient, the driving mechanism  130  can be controlled so as to supply more polishing liquid to the part. In addition, the liquid discharge patterns corresponding to various conditions are employable. 
     Some embodiments of the present invention have been described above in order to facilitate understanding of the present invention without limiting the present invention. The present invention can be changed or improved without departing from the gist thereof, and of course, the equivalents of the present invention are included in the present invention. For example, while the substrate polishing apparatus  10  has been described as a device to polish only one substrate, the substrate polishing apparatus  10  may be a device to simultaneously polish a plurality of substrates. The substrate polishing apparatus  10  may be a device (face-up type device) where the polishing surface of the substrate  112  faces vertically upward, or may be a device where the polishing surface of the substrate  112  faces the horizontal direction. The substrate polishing apparatus  10  is not limited to the CMP apparatus. 
     It is possible to arbitrarily combine or omit respective components according to claims and description in a range in which at least a part of the above-described problems can be solved, or a range in which at least a part of the effects can be exhibited. 
     REFERENCE SIGNS LIST 
     
         
         
           
               10  . . . substrate polishing apparatus 
               20  . . . controller 
               30  . . . storage 
               40  . . . valve 
               100  . . . rotary table 
               101  . . . table rotation shaft 
               102  . . . polishing pad 
               103  . . . table rotation mechanism 
               104  . . . first opening portion 
               105  . . . second opening portion 
               110  . . . polishing head 
               111  . . . head rotation shaft 
               112  . . . substrate 
               113  . . . head rotation mechanism 
               114  . . . head up-and-down motion mechanism 
               120  . . . polishing liquid discharge mechanism 
               121  . . . cylinder 
               122  . . . piston 
               123  . . . liquid holding space 
               124  . . . cleaning liquid supply port 
               130  . . . driving mechanism 
               131  . . . driving fluid supply mechanism 
               132  . . . sensor 
               133  . . . driving fluid supply line 
               140  . . . rotary joint 
               141  . . . supply passage 
               142  . . . discharge passage 
               150  . . . cleaning liquid supply source 
               151  . . . cleaning liquid supply line 
               160  . . . polishing liquid filling mechanism 
               161  . . . arm 
               162  . . . nozzle 
               200  . . . O-ring 
               201  . . . second cylinder 
               202  . . . second piston 
               203  . . . bottom plate 
               204  . . . fluid entering space 
               205  . . . spring 
               301  . . . first magnet 
               302  . . . depressed portion 
               303  . . . second magnet 
               500  . . . electric driving mechanism 
               501  . . . guide 
               502  . . . power source 
               600  . . . polishing liquid