Patent Publication Number: US-11642755-B2

Title: Apparatus for polishing and method for polishing

Description:
TECHNICAL FIELD 
     The present invention relates to an apparatus for polishing and a method for polishing. 
     BACKGROUND ART 
     In a manufacturing process of a semiconductor device, a planarization technique for a semiconductor device surface is becoming more important. Chemical mechanical polishing (CMP) is known as the planarization technique. The chemical mechanical polishing is a technique for performing polishing using a polishing apparatus by bringing a substrate such as a semiconductor wafer into sliding contact with a polishing pad while supplying polishing liquid (slurry) including abrasive grains such as silica (SiO 2 ) or ceria (CeO 2 ) to the polishing pad. 
     A polishing apparatus that performs a CMP process includes a polishing table that supports a polishing pad and a substrate holding mechanism called top ring, polishing head, or the like for holding a substrate. The polishing apparatus supplies polishing liquid from a polishing liquid supply nozzle to the polishing pad and presses the substrate against the surface (a polishing surface) of the polishing pad with a predetermined pressure. At this time, the polishing table and the substrate holding mechanism are rotated, whereby the substrate comes into sliding contact with the polishing surface and the surface of the substrate is polished to be flat and a mirror surface. 
     A polishing rate of the substrate depends on not only a polishing load of the substrate on the polishing pad but also a surface temperature of the polishing pad. This is because chemical action of the polishing liquid on the substrate depends on temperature. Depending on a substrate to be manufactured, it is desired to execute the CMP process at a low temperature in order to prevent deterioration of quality. Therefore, in the polishing apparatus, it is important to keep the surface temperature of the polishing pad during the substrate polishing at an optimum value. Accordingly, in recent years, a polishing apparatus including a temperature adjusting mechanism that adjusts the surface temperature of the polishing pad has been proposed. 
     Meanwhile, polishing liquid used in a CMP apparatus is expensive. Cost is required for disposal of used polishing liquid. Therefore, a reduction in an amount of use of the polishing liquid is requested for reducing operation cost of the CMP apparatus and manufacturing cost of a semiconductor device. Also, it is requested to suppress or prevent the influence of the used polishing liquid and byproducts on the quality of the substrate and/or the polishing rate. 
     CITATION LIST 
     Patent Literature 
     Patent Literature 1: Japanese Patent Application Laid-Open No. 2001-150345 
     Patent Literature 2: Japanese Patent No. 4054306 
     Patent Literature 3: Japanese Patent Application Laid-Open No. 2008-194767 
     Patent Literature 4: United States Patent Publication No. 2016/0167195 
     SUMMARY OF INVENTION 
     Technical Problem 
     An example of slurry use amount reduction includes providing a housing including a recessed section opened to a side facing a polishing pad and a retainer in contact with the polishing pad around the recessed section (Patent Literature 1). In this configuration, a supply path of polishing liquid is provided in the housing to supply the polishing liquid into the recessed section. A thin layer of the polishing liquid is formed by delivering the polishing liquid from a narrow gap between the retainer and the polishing pad. Another example includes supplying polishing liquid to the outer side of a chamfered front edge of a distribution device and pressing the polishing liquid against a polishing pad in a chamfered portion of the front edge to thereby fill the polishing liquid in grooves of the polishing pad, and forming a thin layer of the polishing liquid with a rear edge of the distribution device (Patent Literature 2). In these slurry supplying methods, the configuration is relatively complicated, an effect of the use amount reduction is insufficient, and there is room of improvement. 
     As an example of removal of used polishing liquid, there is a cleaning device for a polishing apparatus in which a suction port coupled to a vacuum pipe and a cleaning nozzle coupled to a pressure water pipe are disposed close to each other side by side (Patent Literature 3). There is an apparatus in which fluid outlets are provided on width direction both sides of a main body of a spray system, a fluid inlet is provided between the fluid outlets on both the sides, and fluid is jetted onto a polishing surface from the fluid outlets on both the sides toward a fluid inlet direction and fluid including used polishing liquid is collected from the fluid inlet (Patent Literature 4). In these configurations, it is necessary to suck and collect jetted cleaning liquid together with the used polishing liquid, whereby a large suction force is required. 
     The present invention has been devised in view of the circumstances described above and an object of the present invention is to solve at least a part of the problems described above. 
     Solution to Problem 
     According to an aspect of the present invention, there is provided an apparatus for polishing an object to be polished using a polishing pad having a polishing surface, the apparatus including: a polishing table for supporting the polishing pad, the polishing table being configured to be rotatable; a substrate holding unit configured to hold the object to be polished and press the object to be polished against the polishing pad; a supplying device configured to supply polishing liquid to the polishing surface in a state in which the supplying device is pressed against the polishing pad; and a pressing mechanism configured to press the supplying device against the polishing pad. The supplying device includes a sidewall pressed against the polishing surface, the sidewall including a first wall on an upstream side in a rotating direction of the polishing table and a second wall on a downstream side in the rotating direction of the polishing table, and a holding space (retaining space) surrounded by the sidewall and opened to the polishing surface, the holding space configured to hold or retain the polishing liquid and supplying the polishing liquid to the polishing surface. The pressing mechanism is capable of respectively adjusting pressing forces to the first wall and the second wall. 
     According to an aspect of the present invention, there is provided an apparatus for polishing an object to be polished using a polishing pad having a polishing surface, the apparatus including: a polishing table for supporting the polishing pad, the polishing table being configured to be rotatable; a substrate holding unit configured to hold the object to be polished and pressing the object to be polished against the polishing pad; and a polishing-liquid removing unit configured to remove the polishing liquid from the polishing surface. The polishing-liquid removing unit includes a cleaning unit configured to jet cleaning liquid onto the polishing surface and a sucking unit configured to suck the polishing liquid on the polishing surface onto which the cleaning liquid is jetted. The cleaning unit includes a cleaning space surrounded by a sidewall. The sidewall includes an opening section for opening the cleaning space toward a radial direction outer side of the polishing table. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG.  1    is a diagram showing a configuration overview of a polishing apparatus according to an embodiment of the present invention; 
         FIG.  2    is a plan view showing a disposition relation among components of the polishing apparatus; 
         FIG.  3    is a diagram schematically showing an example of a polishing-liquid removing unit; 
         FIG.  4    is a diagram for explaining control of a temperature adjusting unit by a control unit; 
         FIG.  5    is a plan view schematically showing a gas jetting nozzle of the temperature adjusting unit and a polishing pad; 
         FIG.  6    is a side view schematically showing the gas jetting nozzle of the temperature adjusting unit and the polishing pad; 
         FIG.  7    is a diagram schematically showing an example of a polishing-liquid removing unit in a modification; 
         FIG.  8    is a diagram for explaining control of a temperature adjusting unit in the modification by the control unit; 
         FIG.  9    is a plan view showing a disposition relation among components of a polishing apparatus according to a second embodiment; 
         FIG.  10    is a plan view showing a schematic shape of a supplying device; 
         FIG.  11    is a sectional view showing the schematic shape of the supplying device; 
         FIG.  12    is a sectional view showing the supplying device and a pressing mechanism; 
         FIG.  13 A  is a perspective view showing a configuration example of the pressing mechanism; 
         FIG.  13 B  is a perspective view showing a configuration example of a pressing-posture adjusting mechanism; 
         FIG.  13 C  is a perspective view showing a configuration example of the pressing mechanism; 
         FIG.  14    is a diagram for explaining discharge of used polishing liquid; 
         FIG.  15 A  is a sectional view for explaining use efficiency of new polishing liquid (the second embodiment); 
         FIG.  15 B  is a plan view for explaining the use efficiency of the new polishing liquid (the second embodiment); 
         FIG.  16 A  is a sectional view for explaining use efficiency of new polishing liquid (a comparative example); 
         FIG.  16 B  is a plan view for explaining the use efficiency of the new polishing liquid (the comparative example); 
         FIG.  17    is a sectional view of a supplying device in which a slit is provided on a secondary side; 
         FIG.  18 A  is an example of the slit on the secondary side; 
         FIG.  18 B  is an example of the slit on the secondary side; 
         FIG.  18 C  is an example of the slit on the secondary side; 
         FIG.  19 A  is a diagram for explaining an accumulating direction of the polishing liquid in the supplying device; 
         FIG.  19 B  is a diagram for explaining the accumulating direction the polishing liquid in the supplying device; 
         FIG.  19 C  is a diagram for explaining the accumulating direction of the polishing liquid in the supplying device; 
         FIG.  20 A  is a plan view showing an example of a shape of the supplying device; 
         FIG.  20 B  is a plan view showing an example of the shape of the supplying device; 
         FIG.  20 C  is a plan view showing an example of the shape of the supplying device; 
         FIG.  21    is a plan view showing a disposition relation among components of a polishing apparatus according to a third embodiment; 
         FIG.  22    is a sectional view of a supplying device in which a slit is provided on a primary side; 
         FIG.  23    is an example of the slit on the primary side; 
         FIG.  24    is a plan view of the supplying device for explaining a flow of collection of polishing liquid; 
         FIG.  25    is a plan view showing an example of a shape of the supplying device; 
         FIG.  26    is a sectional view of a supplying device in which a slit is provided on a secondary side; 
         FIG.  27    is a sectional view of a supplying device in which slits are provided on a primary side and a secondary side; 
         FIG.  28    is a plan view showing a disposition relation among components of a polishing apparatus according to a fourth embodiment; 
         FIG.  29    is a sectional view showing an example of a polishing-liquid removing unit; 
         FIG.  30    is a sectional view showing an example of the polishing-liquid removing unit; 
         FIG.  31    is a plan view showing an example of the polishing-liquid removing unit; 
         FIG.  32    is a diagram schematically showing a configuration example of a nozzle jetting port; 
         FIG.  33    is a diagram schematically showing a configuration example of the nozzle jetting port; 
         FIG.  34 A  is a perspective view showing a configuration example of the polishing-liquid removing unit; 
         FIG.  34 B  is a perspective view showing a configuration example of the polishing-liquid removing unit; 
         FIG.  34 C  is a perspective view showing a configuration example of the polishing-liquid removing unit; 
         FIG.  35    is a perspective view showing a disposition relation among components of a polishing apparatus according to a fifth embodiment; 
         FIG.  36    is a plan view of a polishing-liquid removing unit for explaining discharge of cleaning liquid; 
         FIG.  37    is a perspective view showing an example of an attachment structure of the polishing-liquid removing unit; 
         FIG.  38    is a perspective view showing an example of the attachment structure of the polishing-liquid removing unit; 
         FIG.  39    is a plan view showing a disposition relation among components of a polishing apparatus according to a sixth embodiment; and 
         FIG.  40    is a plan view showing a disposition relation among components of a polishing apparatus according to a seventh embodiment. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Embodiments of the present invention are explained below with reference to the drawings. In the drawings, same or equivalent components are denoted by the same reference numerals or signs and redundant explanation of the components is omitted. 
     First Embodiment 
       FIG.  1    is diagram showing a configuration overview of a polishing apparatus according to an embodiment of the present invention. A polishing apparatus  10  according to this embodiment is configured to be able to perform polishing of a substrate Wk such as a semiconductor wafer serving as an object to be polished (polishing object) using a polishing pad  100  having a polishing surface  102 . As shown in  FIG.  1   , the polishing apparatus  10  includes a polishing table  20  that supports the polishing pad  100  and a top ring (a substrate holding unit)  30  that holds the substrate Wk and presses the substrate Wk against the polishing pad  100 . Further, the polishing apparatus  10  includes a polishing-liquid supply nozzle (a polishing-liquid supplying unit)  40  that supplies polishing liquid (slurry) to the polishing pad  100 . 
     The polishing table  20  is formed in a disk shape and configured to be rotatable with a center axis thereof as a rotation axis. The polishing pad  100  is attached to the polishing table  20  by pasting or the like. The surface of the polishing pad  100  forms the polishing surface  102 . The polishing table  20  is rotated by a not-shown motor, whereby the polishing pad  100  rotates integrally with the polishing table  20 . 
     The top ring  30  holds, on the lower surface thereof, the substrate Wk serving as the object to be polished with vacuum suction or the like. The top ring  30  is configured to be rotatable together with the substrate Wk with power from a not-shown motor. An upper part of the top ring  30  is connected to a supporting arm  34  via a shaft  31 . The top ring  30  is movable in the up-down direction with a not-shown air cylinder and is capable of adjusting the distance to the polishing table  20 . Consequently, the top ring  30  can press the held substrate Wk against the surface (the polishing surface)  102  of the polishing pad  100 . Further, the supporting arm  34  is configured to be swingable by a not-shown motor. The supporting arm  34  moves the top ring  30  in a direction parallel to the polishing surface  102 . In this embodiment, the top ring  30  is configured to be movable to a not-shown receiving position of the substrate Wk and a position above the polishing pad  100 , and is configured to be capable of changing a pressing position of the substrate Wk against the polishing pad  100 . In the following explanation, a pressing position (a holding position) of the substrate Wk by the top ring  30  is referred to as “polishing region” as well. 
     The polishing-liquid supply nozzle  40  is provided above the polishing table  20  and supplies the polishing liquid (the slurry) to the polishing pad  100  supported by the polishing table  20 . The polishing-liquid supply nozzle  40  is supported by a shaft  42 . The shaft  42  is configured to be swingable by a not-shown motor. The polishing-liquid supply nozzle  40  can change a dripping position of the polishing liquid during polishing. 
     The polishing apparatus  10  also includes a control unit  70  (see  FIG.  4   ) that controls the overall operation of the polishing apparatus  10 . The control unit  70  includes a CPU and a memory. The control unit  70  may be configured as a microcomputer that realizes a desired function using software, may be configured as a hardware circuit that performs dedicated arithmetic processing, or may be configured by a combination of the microcomputer and the hardware circuit that performs the dedicated arithmetic processing. 
     In the polishing apparatus  10 , polishing of the substrate Wk is performed as explained below. First, the top ring  30  that holds the substrate Wk on the lower surface is rotated and the polishing pad  100  is rotated. In this state, the polishing liquid is supplied from the polishing-liquid supply nozzle  40  to the polishing surface  102  of the polishing pad  100 . The substrate Wk held by the top ring  30  is pressed against the polishing surface  102 . Consequently, the substrate Wk and the polishing pad  100  relatively move in a state in which the surface of the substrate Wk is in contact with the polishing pad  100  under the presence of the slurry. The substrate Wk is polished in this way. 
     The polishing apparatus  10  further includes a polishing-liquid removing unit  50  and a temperature adjusting unit  60  as shown in  FIG.  1   .  FIG.  2    is a plan view showing a disposition relation among components of the polishing apparatus  10 . As shown in  FIG.  2   , in the polishing apparatus  10  in this embodiment, the polishing-liquid supply nozzle  40 , a polishing region of the substrate Wk (a pressing position of the substrate Wk by the top ring  30 ), the polishing-liquid removing unit  50 , and the temperature adjusting unit  60  are disposed in this order in a rotating direction Rd of the polishing table  20  when the polishing of the substrate Wk is performed. In this embodiment, the polishing-liquid removing unit  50  and the temperature adjusting unit  60  are provided adjacent to each other. However, the polishing-liquid removing unit  50  and the temperature adjusting unit  60  may be provided to be separated without being limited to such an example. 
     The polishing-liquid removing unit  50  is provided in order to remove the polishing liquid from the polishing surface  102  further in the rear (on a downstream side) in the rotating direction Rd of the polishing table  20  than the polishing region of the substrate Wk. In other words, the polishing-liquid removing unit  50  removes, from the polishing surface  102 , the polishing liquid used once for the polishing of the substrate Wk. As shown in  FIG.  2   , the polishing-liquid removing unit  50  is disposed to extend along the radial direction of the polishing table  20 . 
       FIG.  3    is a diagram schematically showing an example of the polishing-liquid removing unit  50 . In  FIG.  3   , a cross section perpendicular to the longitudinal direction of the polishing-liquid removing unit  50  (the radial direction of the polishing table  20 ) is shown. As shown in  FIG.  3   , the polishing-liquid removing unit  50  in this embodiment includes a damming unit  52  that dams polishing liquid SL on the polishing surface  102  and a sucking unit  56  that sucks the polishing liquid SL. In this embodiment, the damming unit  52  and the sucking unit  56  are integrally configured. 
     The damming unit  52  comes into contact with the polishing surface  102  and prevents the polishing liquid SL from moving in the rotating direction Rd of the polishing table  20 . The material of the damming unit  52  is desirably selected such that the damming unit  52  does not scratch the polishing surface  102  and chips of the damming unit  52  itself due to the contact with the polishing surface  102  do not remain on the polishing surface  102 . As an example, the damming unit  52  may be made of the same material as the material of a not-shown retainer ring that holds the outer circumferential edge of the substrate Wk or may be made of synthetic resin such as PPS (polyphenylene sulfide) or metal such as stainless steel. Resin coating of PEEK (polyether ketone), PTFE (polytetrafluoroethylene), or polyvinyl chloride may be applied to the surface of the damming unit  52 . Further, as shown in  FIG.  3   , in the damming unit  52 , a part in contact with the polishing surface  102  may be round-chamfered (or square-chamfered) such that contact resistance of the polishing surface  102  decreases. 
     The sucking unit  56  is disposed adjacent to the front (an upstream side) of the damming unit  52  in the rotating direction Rd of the polishing table  20 . The sucking unit  56  includes a slit  57  opened toward the polishing surface  102 . A not-shown vacuum source is connected to the slit  57  via a channel  58 . In this embodiment, the channel  58  extending from the slit  57  to the not-shown vacuum source forms an angle of 90 degrees with respect to the polishing surface  102 . The slit  57  is desirably formed shorter than the length of the damming unit  52  and longer than the diameter of the substrate Wk in the longitudinal direction of the polishing-liquid removing unit  50 . Width Sw of the slit  57  may be decided based on a type of the polishing liquid SL, performance of the not-shown vacuum source, and the like. As an example, when the diameter of the substrate Wk is 300 mm, the length in the longitudinal direction of the slit  57  is desirably 300 mm or more and the width Sw is desirably approximately 1 mm to 2 mm. 
     In this way, in the polishing-liquid removing unit  50  in this embodiment, in the rotating direction Rd of the polishing table  20 , the damming unit  52  that dams the polishing liquid SL is disposed continuously behind the sucking unit  56  that sucks the polishing liquid SL. Therefore, the polishing liquid SL dammed by the damming unit  52  can be sucked by the sucking unit  56 . The polishing liquid SL can be suitably removed from the polishing surface  102 . 
     The polishing-liquid removing unit  50  is desirably separated from the polishing surface  102  when the polishing surface  102  is conditioned by a not-shown atomizer or dresser. In other words, the polishing-liquid removing unit  50  may be configured to be movable to a polishing liquid removing position for removing the polishing liquid SL and a standby position apart from the polishing surface  102 , and may be located in the standby position when the conditioning of the polishing surface  102  is performed. The polishing apparatus  10  in this embodiment can perform the conditioning of the polishing surface  102  in a state in which the polishing liquid is removed from the polishing surface  102  by the polishing-liquid removing unit  50 . Accordingly, liquid used by the atomizer or the dresser and the polishing liquid can be prevented from mixing. Therefore, it is possible to respectively collect used liquid caused by the polishing and the conditioning of the substrate Wk. It is possible to contribute to environment preservation. 
     Referring back to  FIGS.  1  and  2   , the temperature adjusting unit  60  is disposed behind the polishing-liquid removing unit  50  in the rotating direction Rd of the polishing table  20 . The temperature adjusting unit  60  is controlled by the control unit to adjust the temperature of the polishing surface  102 .  FIG.  4    is a diagram for explaining the control of the temperature adjusting unit  60  by the control unit. In  FIG.  4   , illustration of the polishing-liquid removing unit  50  is omitted. As shown in  FIG.  4   , the temperature adjusting unit  60  in this embodiment includes a gas jetting nozzle (an injector)  62  for spraying gas to the polishing surface  102 . The gas jetting nozzle  62  is connected to a compressed air source via a compressed air supply line  63 . A pressure control valve  64  is provided in the compressed air supply line  63 . Compressed air supplied from the compressed air source passes through the pressure control valve  64 , whereby pressure and a flow rate are controlled. The pressure control valve  64  is connected to the control unit  70 . The compressed air may have a normal temperature or may be cooled or heated to a predetermined temperature. 
     As shown in  FIG.  4   , a temperature sensor  68  that detects the surface temperature of the polishing pad  100  is set above the polishing pad  100 . It is desirable that the temperature sensor  68  is provided behind the polishing-liquid removing unit  50  in the rotating direction Rd of the polishing table  20  and detects the temperature of the polishing surface  102  in a state in which the polishing liquid is removed. The temperature sensor  68  is connected to the control unit  70 . The control unit  70  adjusts a valve opening degree of the pressure control valve  64  with PID control according to a difference between a target temperature, which is a predetermined temperature or an input setting temperature, and an actual temperature of the polishing surface  102  detected by the temperature sensor  68 , and controls a flow rate of the compressed air jetted from the gas jetting nozzle  62 . Consequently, the compressed air having an optimum flow rate is blown against the polishing surface  102  of the polishing pad  100  from the gas jetting nozzle  62 . The temperature of the polishing surface  102  is maintained at the target temperature. 
       FIGS.  5  and  6    are a plan view and a side view schematically showing the gas jetting nozzle  62  of the temperature adjusting unit  60  and the polishing pad  100 . As shown in  FIG.  5   , the temperature adjusting unit  60  includes a plurality of gas jetting nozzles  62  disposed at every predetermined interval along the radial direction of the polishing table  20  (eight nozzles are attached in an example shown in  FIG.  5   ). In  FIG.  5   , the polishing pad  100  rotates in clockwise direction Rd around a rotation center CT during polishing. The nozzles are numbered in ascending order of 1, 2, 3, . . . , and 8 from the pad inner side. For example, third and sixth two gas jetting nozzles  62  are explained as an example. When concentric circles C 1  and C 2  passing points P 1  and P 2  immediately below the third and sixth two gas jetting nozzles  62  and centering on CT are drawn and a tangential direction at the points P 1  and P 2  on the concentric circles C 1  and C 2  is defined as a rotation tangential direction of the polishing pad  100 , a gas jetting direction of the gas jetting nozzles  62  is tilted by a predetermined angle (θ1) to the pad center side with respect to the rotation tangential direction of the polishing pad. The gas jetting direction means a direction of the center line of an angle (a gas jetting angle) at which the gas spreads in a fan shape from gas jetting nozzle ports. The nozzles other than the third and sixth nozzles are also tilted by the predetermined angle (θ1) to the pad center side with respect to the rotation tangential direction of the polishing pad. The angle (θ1) in the gas jetting direction of the gas jetting nozzles  62  with respect to the rotation tangential direction of the polishing pad is set to 15° to 35° in a relation with a temperature adjusting ability. In the above explanation, there are the eight nozzles. However, the number of nozzles can be adjusted by closing nozzle holes with plugs or the like and can be set to any number. The number of nozzles is selected as appropriate according to, for example, the size of the polishing pad  100 . 
     As shown in  FIG.  6   , the gas jetting direction of the gas jetting nozzle  62  is not perpendicular to the surface (the polishing surface)  102  of the polishing pad  100  and is tilted by a predetermined angle to the rotating direction Rd side of the polishing table  20 . When the angle in the gas jetting direction of the gas jetting nozzle  62  with respect to the polishing surface  102 , that is, an angle formed by the polishing surface  102  and the gas jetting direction of the gas jetting nozzle  62  is defined as a gas entry angle (θ2), the gas entry angle (θ2) is set to 30° to 50° in a relation with a temperature adjusting ability. The gas jetting direction means a direction of the center line of an angle (a gas jetting angle) at which the gas spreads in a fan shape from gas jetting nozzle ports. As shown in  FIG.  6   , the gas jetting nozzle  62  is configured to be movable up and down. Height Hn from the polishing surface  102  of the gas jetting nozzle  62  can be adjusted. 
     The temperature of the polishing surface  102  can be adjusted by the temperature adjusting unit  60  by jetting the gas from at least one gas jetting nozzle  62  toward the polishing pad  100  (the polishing surface  102 ) during the polishing of the substrate Wk. Moreover, the polishing-liquid removing unit  50  that removes the polishing liquid from the polishing surface  102  is provided in the front of the temperature adjusting unit  60  in the rotating direction Rd of the polishing table  20 . Therefore, the temperature adjusting unit  60  can adjust the temperature of the polishing surface  102  in a state in which the polishing liquid, which could be a heat insulating layer, is removed. Efficiency of the temperature adjustment of the polishing surface  102  can be improved. Even when the gas is powerfully jetted onto the polishing surface  102  from the gas jetting nozzle  62  of the temperature adjusting unit  60 , the polishing liquid is suppressed from scattering and occurrence of scratches of the substrate Wk can be suppressed. Further, in the polishing apparatus  10  in this embodiment, the polishing liquid once used for the polishing of the substrate Wk is removed by the polishing-liquid removing unit  50 . New polishing liquid is supplied from the polishing-liquid supply nozzle  40  to the polishing surface  102  every time. Therefore, it is possible to keep the quality of the polishing liquid used for the polishing of the substrate Wk constant. 
     (Modification 1) 
       FIG.  7    is a diagram schematically showing an example of a polishing-liquid removing unit in a modification. In the embodiment explained above, the slit  57  and the channel  58  of the sucking unit  56  are provided at 90 degrees with respect to the polishing surface  102 . However, without being limited to such an example, as shown in  FIG.  7   , the slit  57  and the channel  58  of the sucking unit  56  may be inclined such that an angle formed with the rotating direction Rd of the polishing table  20  is 10 degrees or more and less than 90 degrees. Consequently, it is possible to guide the polishing liquid SL to the channel  58  according to the rotation of the polishing table  20  and suitably suck the polishing liquid SL. 
     In the embodiment explained above, the damming unit  52  of the sucking unit  56  comes into contact with the polishing surface  102 . However, without being limited by such an example, the damming unit  52  only has to be in contact with the polishing liquid and may be provided to have a gap between the damming unit  52  and the polishing surface  102 . In this case, since the damming unit  52  and the polishing surface  102  do not come into contact, it is possible to prevent chips of the damming unit  52  from being formed and prevent contact resistance from occurring. The polishing apparatus  10  may further include a sensor that detects the position of the polishing surface  102  or the distance between the polishing-liquid removing unit  50  and the polishing surface  102 . The polishing apparatus  10  may bring the polishing-liquid removing unit  50  into contact with the polishing surface  102  based on the detected position or distance, or may keep the distance between the polishing-liquid removing unit  50  and the polishing surface  102  constant. 
     Further, in the embodiment explained above, the polishing-liquid removing unit  50  integrally includes the damming unit  52  and the sucking unit  56 . However, without being limited to such an example, the polishing-liquid removing unit  50  may separately include the damming unit  52  and the sucking unit  56 , or may include only one of the damming unit  52  and the sucking unit  56 . At least part of the polishing-liquid removing unit  50  may be provided in an integral manner with the dresser, the atomizer, or the like for conditioning the polishing pad  100 . 
     (Modification 2) 
       FIG.  8    is a diagram for explaining control of a temperature adjusting unit  60 A in a modification by the control unit. The temperature adjusting unit  60  in the embodiment explained above includes the gas jetting nozzle (the injector)  62  that jets the gas toward the polishing surface  102 . However, the temperature adjusting unit  60  may include a heat exchanger, on the inside of which fluid flows, instead of or in addition to the gas jetting nozzle (the injector)  62 . As shown in  FIG.  8   , the temperature adjusting unit  60 A in the modification includes a heat exchanger  62 A instead of the gas jetting nozzle  62 . The modification shown in  FIG.  8    is the same as the polishing apparatus  10  in the embodiment except the temperature adjusting unit  60 A. In  FIG.  8   , illustration of the polishing-liquid removing unit  50  is omitted. As shown in  FIG.  8   , a not-shown channel is formed on the inside of the heat exchanger  62 A. The heat exchanger  62 A is connected to a fluid supply source  66 A via a pipe  63 A. A pressure control valve  64 A is provided in the pipe  63 A. Fluid supplied from the fluid supply source  66 A passes through the pressure control valve  64 A, whereby pressure and a flow rate of the fluid are controlled. The pressure control valve  64 A is connected to the control unit  70 . As the fluid used in the heat exchanger  62 A, liquid such as water may be used or gas such as air may be used. Reaction gas may be fed into the inside of the heat exchanger  62 A, and a catalyst for facilitating heat generation reaction of the reaction gas may be provided on the inside of the heat exchanger  62 A. Further, the heat exchanger  62 A may be disposed in contact with the polishing surface  102  or may be disposed to have a gap between the heat exchanger  62 A and the polishing surface  102 . 
     As in the embodiment explained above, the control unit  70  adjusts a valve opening degree of the pressure control valve  64 A based on temperature detected by the temperature sensor  68  and controls a flow rate of fluid flowing to the inside of the heat exchanger  62 A. With such a temperature adjusting unit  60 A in the modification, as in the embodiment explained above, it is possible to adjust the temperature of the polishing surface  102 . Moreover, the polishing-liquid removing unit  50  is provided in the front of the temperature adjusting unit  60 A in the rotating direction Rd of the polishing table  20 . Therefore, in the polishing apparatus in the modification, temperature adjustment of the polishing surface  102  by the temperature adjusting unit  60 A can be performed in a state in which the polishing liquid, which could be a heat insulating layer, is removed. It is possible to improve efficiency of the temperature adjustment of the polishing surface  102 . 
     Second Embodiment 
       FIG.  9    is a plan view showing a disposition relation among components of the polishing apparatus  10  according to a second embodiment. In the following explanation, the same components as the components in the embodiment explained above are denoted by the same reference numerals or signs and detailed explanation of such components is omitted. In this embodiment, the polishing apparatus  10  includes a supplying device (a slurry pad)  200  for supplying polishing liquid to the polishing pad  100 . The supplying device  200  has a shape of a pad or a box. The supplying device  200  is pressed against the polishing surface  102  of the polishing pad  100  by a pressing mechanism  250  explained below. A dresser  90  and an atomizer  94  are also shown in  FIG.  9   . The dresser  90  is connected to a shaft  92  via an arm  93 . The shaft  92  is configured to be swingable by a not-shown motor. The shaft  92  is capable of moving the dresser  90  on the polishing pad  100  and capable of moving the dresser  90  to a standby position outside the polishing pad  100 . The dresser  90  is configured to be movable up and down by a not-shown lifting and lowering mechanism and configured to be pressed against the polishing pad  100 . The atomizer  94  is configured to be capable of supplying pure water (DIW) to the polishing surface of the polishing pad  100 . The dresser  90  and the atomizer  94  can be omitted. 
       FIG.  10    is a plan view showing a schematic shape of the supplying device  200 .  FIG.  11    is a sectional view showing the schematic shape of the supplying device  200 . The supplying device  200  has an elongated shape in a plan view and includes, on the inside thereof, a holding space  201  surrounded by a sidewall  210 . The length of the supplying device  200  is generally formed the same as the diameter of the substrate Wk held by the top ring  30 . Like the damming unit  52  explained above, as the material of the sidewall  210  of the supplying device  200 , the same material as the material of the damming unit  52  is desirably selected such that the polishing surface  102  is not scratched and chips of the sidewall  210  itself due to contact with the polishing surface  102  do not remain on the polishing surface  102 . 
     The sidewall  210  includes a sidewall  211  located on an upstream side in the rotating direction Rd of the polishing table  20  and a sidewall  212  located on a downstream side in the rotating direction Rd. A side of the supplying device  200  facing the polishing surface  102  of the polishing pad  100  is opened (an opening section  221 ). In other words, the holding space  201  is opened on or to the polishing surface  102 . An upper part of the supplying device  200  is closed by a top plate  220  integral with or separate from the sidewall  210 . When the top plate  220  is separate, the top plate  220  can be configured as a top cover attachable to the sidewall  210 . One or a plurality of introducing sections  222  for introducing polishing liquid are provided in the top plate  220 . Polishing liquid (slurry) SLf is supplied from the polishing-liquid supply nozzle  40  to the holding space  201  in the supplying device  200  via the introducing section(s)  222 . When the plurality of introducing sections  222  are present, the polishing-liquid supply nozzle  40  includes a plurality of nozzle tips branching according to the number of the introducing sections  222 . In the following explanation, the polishing liquid before being used for polishing treatment is sometimes described as SLf and the polishing liquid after being used for the polishing treatment is sometimes described as SLu. 
       FIG.  12    is a sectional view showing the supplying device  200  and the pressing mechanism  250 . The pressing mechanism  250  is disposed above the supplying device  200  and includes a cylinder device  251  and a pressing-posture adjusting mechanism  252 . The pressing mechanism  250  is connected to a shaft  254  via an arm  253 . The shaft  254  is configured to be swingable by a motor  255 . The pressing mechanism  250  is swingable by rotation of the shaft  254 . Instead of separately providing the shaft  254 , the pressing mechanism  250  may be connected to the shaft  42  of the polishing-liquid supply nozzle  40  via the arm  253 . The tip of the polishing-liquid supply nozzle  40  is connected to the introducing sections  222  of the supplying device  200 . The polishing liquid SL is supplied from the polishing-liquid supply nozzle  40 . 
     The cylinder device  251  can include a plurality of cylinders  251   a  along the longitudinal direction of the supplying device  200  and/or the width direction of the supplying device  200  (the polishing table rotating direction Rd). The cylinders include rods driven by fluid (gas or liquid). In this embodiment, as shown in  FIG.  13 A , the cylinder device  251  is configured such that three cylinders  251   a  are disposed side by side along the width direction of the supplying device  200 . The cylinders  251   a  are connected to a fluid supply source (not shown in  FIG.  13 A ) via electric pneumatic regulators (proportional control valves)  71 . The electric pneumatic regulators  71  are connected to the control unit  70 . The control unit  70  controls the electric pneumatic regulators  71 , whereby pressure and a flow rate of driving fluid supplied from the not-shown fluid supply source to the cylinders  251   a  are controlled. Pressing forces of the cylinders  251   a  are adjusted. The pressing forces of the cylinders  251   a  are adjusted, whereby a pressing force of the sidewall  211  on the upstream side being pressed against the polishing surface  102  is adjusted and a pressing force of the sidewall  212  on the downstream side being pressed against polishing surface  102  is adjusted. The pressing force to the sidewall  211  and the pressing fore to the sidewall  212  can be respectively separately adjusted (to be the same or different). An example is explained in which the three cylinders  251   a  disposed side by side in the width direction of the supplying device  200  are provided. However, two or four or more cylinders  251   a  disposed side by side in the width direction may be provided. It is possible to individually adjust the pressing force to the sidewall  211  and the pressing force to the sidewall  212  if there are two cylinders including a cylinder that presses the sidewall  211  side and a cylinder that presses the sidewall  212  side. Instead of the cylinder device, another pressing device including a plurality of pressing means (rods driven by power of solenoids, other motors, or the like) may be adopted. 
     It is possible to prevent used polishing liquid SLu from intruding into the holding space  201  from the sidewall  211  and discharge the used polishing liquid SLu to the outside of the polishing pad  100  along the sidewall  211  by controlling the pressing forces of the plurality of cylinders  251   a  to adjust the pressing force to the sidewall  211  on the upstream side ( FIG.  14   ). It is possible to collect at least a part of the used polishing liquid SLu in the holding space  201  from a gap between the sidewall  211  and the polishing surface  102  by adjusting the pressing force to the sidewall  211  on the upstream side ( FIGS.  21 ,  26 , and  27   ). 
     A plurality of cylinders disposed side by side in the longitudinal direction of the supplying device  200  may be provided. In this case, pressing forces to places in the longitudinal direction of the supplying device  200  can be adjusted to be different. 
     As shown in  FIGS.  13 A and  13 B , the pressing-posture adjusting mechanism  252  is disposed between the cylinder device  251  and the supplying device  200  and adjusts the posture of the supplying device  200 . The pressing-posture adjusting mechanism  252  includes a first block  252   a , a second block  252   b  fixed to the first block  252   a , and a third block  252   c  rotatably engaged with the second block  252   b  via a shaft  252   d . The first block  252   a  is fixed to the rods of the cylinders  251   a  of the cylinder device  251 . The third block  252   c  is fixed to the supplying device  200 . With this configuration, when the supplying device  200  is placed on the polishing surface  102 , the third block  252   c  of the pressing-posture adjusting mechanism  252  rotates around the shaft  252   d  with respect to the second block  252   b  and the supplying device  200  is set in parallel to the polishing surface  102 . 
     In  FIG.  13 A , an example is shown in which the pressing-posture adjusting mechanism  252  is fixed to the top plate (top cover)  220  of the supplying device  200 . However, as shown in  FIG.  13 C , the top plate (top cover)  220  may be omitted and the pressing-posture adjusting mechanism  252  may be fixed to the sidewall  210  of the supplying device  200 . 
       FIG.  14    is a diagram for explaining discharge of used polishing liquid. As shown in  FIG.  14   , the supplying device  200  includes the sidewall  211  on the upstream side in the rotating direction Rd of the polishing pad  100  (a primary side; the downstream side of the top ring  30 ) and the sidewall  212  on the downstream side in the rotating direction Rd of the polishing pad  100  (a secondary side; the upstream side of the top ring  30 ). As shown in  FIG.  14   , it is possible to prevent the polishing liquid SLu used for the polishing treatment in the top ring  30  from intruding into the holding space  201  in the supplying device  200  via the sidewall  211  and it is possible to discharge the used polishing liquid SLu to the outside of the polishing pad  100  with a centrifugal force by the rotation of the polishing table  20  by appropriately adjusting, with the pressing mechanism  250  explained above, a pressing force of the sidewall  211  on the primary side being pressed against the polishing surface  102  of the polishing pad  100 . A discharge amount of the used polishing liquid SLu can be adjusted by adjusting a shape and an angle of the sidewall  211  of the supplying device  200  ( FIGS.  19 A to  19 C and  20 A to  20 C ), a pressing force to the sidewall  211  by the pressing mechanism  250 , and/or the configuration (the number, disposition, height, a shape, and dimensions (when the slits are provided, as explained below)) of the slits of the sidewall  211 . 
     It is possible to supply new polishing liquid SLf from the holding space  201  of the supplying device  200  to the top ring  30  side via a gap between the sidewall  212  and the polishing surface  102  and it is possible to adjust a supply amount of the new polishing liquid SLf by appropriately adjusting, with the pressing mechanism  250 , a pressing force of the sidewall  212  on the secondary side being pressed against the polishing surface  102  of the polishing pad  100 . Therefore, with the supplying device  200 , the used polishing liquid SLu can be discharged by the sidewall  211  on the primary side and the supply amount of the new polishing liquid SLf can be adjusted by the sidewall  212  on the secondary side. As a result, it is possible to execute the polishing treatment of the substrate Wk with the top ring  30  substantially using only new polishing liquid. It is possible to improve polishing quality (a polishing rate, in-plane uniformity, and the like). 
       FIGS.  15 A and  15 B  are diagrams for explaining use efficiency of new polishing liquid according to the second embodiment.  FIGS.  16 A and  16 B  are sectional views for explaining use efficiency of new polishing liquid according to a comparative example. As shown in  FIGS.  16 A and  16 B , when the polishing liquid is supplied from the polishing-liquid supply nozzle  40  to the polishing surface  102  without using the supplying device  200  according to this embodiment, it is necessary to supply the polishing liquid more than the polishing liquid used for actual polishing treatment in order to supply the polishing liquid to the entire substrate Wk held by the top ring  30 . Therefore, as shown in  FIG.  16 B , it is likely that a lot of new polishing liquid SLf is discharged, without being used for the polishing treatment, by a centrifugal force by the rotation of the polishing pad  100  and pressing of the retainer ring of the top ring  30 . On the other hand, in this embodiment, when the polishing surface  102  of the polishing pad  100  passes through the supplying device  200 , the polishing liquid SLf is supplied to the polishing surface  102  in the holding space  201 , and when the polishing surface  102  of the polishing pad  100  passes the gap between the sidewall  212  and the polishing surface  102 , an amount of the polishing liquid on the polishing surface  102  is adjusted. In this case, by adjusting a pressing force to the supplying device  200  (the sidewall  212 ) by the pressing mechanism  250 , a supply amount is adjusted such that an amount of the polishing liquid necessary for the polishing treatment remains after the polishing surface  102  of the polishing pad  100  passes the sidewall  212 . For example, the amount of the polishing liquid is adjusted such that the polishing liquid remains mainly in one or more groove sections (pad grooves; porous sections)  101  of the polishing surface  102 . The amount of the polishing liquid in sections other than the groove sections  101  can be reduced. In an example, the polishing liquid in the sections other than the groove sections  101  is supplied as a thin layer on the polishing surface. Consequently, as shown in  FIG.  15 B , on the secondary side (the top ring  30  side) of the supplying device  200 , it is possible to greatly reduce an amount of new polishing liquid discharged without being used for the polishing treatment. In other words, with the supplying device  200  in this embodiment, by appropriately adjusting a pressing force to the sidewall  212  on the secondary side of the supplying device  200 , it is possible to supply the polishing liquid to a necessary portion at a necessary amount and it is possible to reduce an amount of new polishing liquid discharged without being used for the polishing treatment. The length of the supplying device  200  may be optional. Meanwhile, the length of the supplying device  200  may be generally the same as a substrate diameter or may be the same as a radius, which is a half of the substrate diameter, from a relative relation with the diameter of the substrate Wk held by the top ring  30 . The length of the supplying device  200  may be set such that the polishing liquid can be supplied to the entire surface of the substrate Wk or a desired range of the substrate Wk by a desired amount. 
     An output amount of the polishing liquid on the secondary side (a flow rate of the polishing liquid output from between the sidewall  212  and the polishing surface  102 ) is adjusted by adjusting a shape and an angle of the sidewall  212  of the supplying device  200  (an angle of the sidewall  212 : see  FIGS.  19 A to  19 C and  20 A to  20 C ), a pressing force to the sidewall  212  by the pressing mechanism  250 , and/or the configuration (the number, disposition, height, a shape, and dimensions (when the slits are provided, as explained below)) of the slits of the sidewall  212 . 
       FIG.  17    is a sectional view of the supplying device  200  in which a slit is provided on the secondary side.  FIGS.  18 A to  18 C  are examples of the slit on the secondary side and are arrow views from a direction of an arrow XVIII in  FIG.  17   . As shown in  FIGS.  17  and  18 A to  18 C , a slit  231  may be provided in the sidewall  212  on the secondary side and the polishing liquid may be supplied from the holding space  201  via the slit  231  in order to control a supply amount and distribution to places of the polishing liquid from the supplying device  200 . Consequently, flexibility of adjustment of a supply amount of the polishing liquid from the supplying device  200  (the sidewall  212 ) can be improved. For example, as shown in  FIGS.  18 A to  18 C , a supply amount of the polishing liquid from the center in the longitudinal direction of the supplying device  200  may be increased. In this case, the slit  231  in the center in the longitudinal direction can be aligned with a track Ck on which the center of the substrate Wk on the polishing surface  102  passes (see  FIG.  19 C ). Consequently, more polishing liquid can be supplied to the center of the substrate Wk. A flow rate of the polishing liquid flowing to the substrate center is adjusted by adjusting shapes and angles of the sidewalls  211  and  212  of the supplying device  200  (an angle of the sidewall  212 :  FIGS.  19 A to  19 C and  20 A to  20 C ), the configuration (the number, disposition, height, a shape, and dimensions) of slits, and a pressing force by the pressing mechanism  250 . 
     In the example shown in  FIG.  18 A , the slit  231  opened at a lower end edge in the center in the longitudinal direction of the sidewall  212  is provided. Consequently, it is possible to actively supply the polishing liquid to the center of the substrate Wk. In the example shown in  FIG.  18 A , other slits may be added. 
     In the example shown in  FIG.  18 B , the slit  231  opened in a position higher than the lower end edge in the center in the longitudinal direction of the sidewall  212  is provided. In this case, after the polishing liquid is accumulated or held to the height of the slit  231  in the holding space  201  of the supplying device  200 , the polishing liquid is supplied from the slit  231  to the top ring  30  side. In the example shown in  FIG.  18 B , other slits may be added. 
     In the example shown in  FIG.  18 C , a plurality of slits  231  are provided in the longitudinal direction of the sidewall  212 . The height of the slit  231  in the center is the smallest. The heights of the slits  231  increase further away from the center. In this case, a flow rate of the polishing liquid from the slit  231  in the center is the largest. Flow rates of the polishing liquid from the slits  231  decrease further away from the center. It is possible to adjust the flow rates of the polishing liquid from the slits  231  by adjusting the heights of the slits  231 . 
     Besides the illustrations in  FIGS.  18 A to  18 C , slits can be provided by any number, in any disposition, at any height, and in any shape and dimensions in the sidewall on the secondary side. For example, not only in the center of the substrate Wk, one or a plurality of slits can be provided according to a process such that a flow rate from a slit in any position increases or decreases. 
       FIGS.  19 A to  19 C  are diagrams for explaining an accumulating direction of the polishing liquid in the supplying device  200 .  FIGS.  20 A to  20 C  are plan views showing examples of the shape of the supplying device  200 . 
     As shown in  FIGS.  19 A and  20 A , when the radial-direction outer side end portion in the polishing pad  100  of the sidewall  212  on the secondary side of the supplying device  200  is disposed to precede the other portions in the rotating direction Rd, the polishing liquid SLf in the holding space  201  of the supplying device  200  flows from the inner side toward the outer side and is accumulated from the outer side. The radial-direction outer side end in the polishing pad  100  of the sidewall  211  on the primary side of the supplying device  200  is disposed to precede the other portions in the rotating direction Rd. The used polishing liquid SLu is enabled to easily flow outward in the radial direction by the sidewall  211 . In this case, as shown in  FIG.  20 A , the holding space  201  of the supplying device  200  can be formed to expand on the radial direction outer side of the polishing pad  100  in a plan view. 
     As shown in  FIGS.  19 B and  20 B , when the radial-direction inner side end portion in the polishing pad  100  of the sidewall  212  on the secondary side of the supplying device  200  is disposed to precede the other portions in the rotating direction Rd, the polishing liquid SLf in the holding space  201  of the supplying device  200  flows from the outer side toward the inner side and is accumulated from the inner side. On the other hand, the radial-direction outer in the polishing pad  100  of the sidewall  211  on the primary side of the supplying device  200  is disposed to precede the other portions in the rotating direction Rd. The used polishing liquid SLu is enabled to easily flow outward in the radial direction by the sidewall  211 . In this case, as shown in  FIG.  20 B , the holding space  201  of the supplying device  200  can be formed to expand on the radial direction inner side of the polishing pad  100  in a plan view. 
     As shown in  FIGS.  19 C and  20 C , when the center of the sidewall  212  on the secondary side of the supplying device  200  is disposed to precede in the rotating direction Rd, the polishing liquid in the holding space  201  of the supplying device  200  flows from both the sides toward the center and is accumulated from the center side. In this example, the sidewall  212  has a shape bent near the center. On the other hand, the radial-direction outer side end portion in the polishing pad  100  of the sidewall  211  on the primary side of the supplying device  200  is disposed to precede the other portions in the rotating direction Rd. The used polishing liquid SLu is enabled to easily flow outward in the radial direction by the sidewall  211 . In this case, as shown in  FIG.  20 C , the holding space  201  of the supplying device  200  can be formed to expand on the center side in a plan view. The center of the supplying device  200  can be aligned with the track Ck on which the center of the substrate Wk passes. With this configuration, it is possible to accumulate the polishing liquid in the holding space  201  from the center side. It is possible to actively supply the polishing liquid to the center of the substrate. 
     Besides the illustrations in  FIGS.  19 A to  19 C and  20 A to  20 C , the supplying device  200  can be configured to accumulate the polishing liquid from any position in the longitudinal direction of the supplying device  200 . For example, in a portion where the polishing liquid is desired to be accumulated first, the sidewall  212  on the secondary side is disposed to precede in the rotating direction of the polishing pad  100  than the other portions. The polishing liquid can be actively supplied from the portion. 
     It is possible to adjust a supply amount of the polishing liquid output from the supplying device  200  according to a place by adjusting a direction of accumulation of the polishing liquid in the holding space  201  of the supplying device  200  as explained above. For example, when a lot of polishing liquid is supplied to the center of the substrate, the polishing liquid is accumulated from the center side in the holding space  201 . Further, slits may be provided in the sidewall  212  on the downstream side to increase a supply amount to the substrate center (see  FIGS.  18 A to  18 C ). 
     According to this embodiment, the used polishing liquid is discharged on the primary side of the supplying device  200  and new polishing liquid is supplied to the substrate from the secondary side. Polishing can be performed using only the new polishing liquid. Consequently, it is possible to improve polishing quality (a polishing rate, in-plane uniformity, and the like). It is also possible to suppress defects of the substrate due to the polishing treatment. Separate components for removing the used polishing liquid can be omitted. 
     Third Embodiment 
       FIG.  21    is a plan view showing a disposition relation among components of a polishing apparatus according to a third embodiment. Illustration of a dresser and an atomizer is omitted. However, the dresser and the atomizer may be set according to necessity. In this embodiment, the supplying device  200  collects, on the primary side, at least a part of the used polishing liquid SLu in the holding space  201 . The supplying device  200  mixes the used polishing liquid SLu and polishing liquid supplied anew (new polishing liquid) SLf in the holding space  201  and outputs mixed polishing liquid to the secondary side. In  FIG.  21   , for convenience of explanation, the polishing liquid output from the supplying device  200  is indicated by respective arrows of the new polishing liquid SLf and the used polishing liquid SLu. However, actually, the mixed polishing liquid of the new polishing liquid SLf and the used polishing liquid SLu is output. 
     It is possible to further reduce a consumption amount of the polishing liquid by collecting and reusing at least a part of the used polishing liquid SLu. It is known that, depending on a process, it is possible to improve polishing quality (a polishing rate, in-plane uniformity, and the like) by mixing the used polishing liquid SLu in the new polishing liquid SLf and using the mixed liquid for the polishing treatment. Therefore, according to this embodiment, it is possible to further reduce the consumption amount of the polishing liquid and it is possible to improve the polishing quality. It is possible to suppress defects of the substrate due to the polishing treatment. 
       FIG.  22    is a sectional view of a supplying device in which slits are provided on the primary side.  FIG.  23    is an example of the slits on the primary side and is an arrow view from a direction of an arrow XXIII in  FIG.  22   .  FIG.  24    is a plan view of the supplying device for explaining a flow of collection of the polishing liquid. As shown  FIGS.  22  to  24   , slits  232  and  233  for causing the holding space  201  to communicate with the outside are provided in the sidewall  211  on the primary side of the supplying device  200 . The slit  232  is a slit for collecting the used polishing liquid. The used polishing liquid is collected in the holding space  201  via the slit  232  by a force of the rotation of the polishing table  20 . The slit  233  is a slit for returning the polishing liquid overflowing in the holding space  201  to the side of the sidewall  211  on the primary side. Consequently, the used polishing liquid and the polishing liquid in the holding space  201  are satisfactorily mixed. Only one of the slits  232  and  233  may be provided. 
     As shown in  FIG.  23   , the slit  232  is disposed substantially in the center in the longitudinal direction of the sidewall  211  and opened at the lower end edge of the sidewall  211 . A plurality of slits  233  are disposed on both sides of the slit  232  and increase in height further away from the slit  232 . The slits  232  and  233  can be provided by any numbers, in any disposition, at any heights, and in any shapes and dimensions. The slits  232  for collection may be provided in plurality. The slit  233  for discharge may be provided in singularity. 
     During the polishing treatment, as shown in  FIGS.  23  and  24   , the polishing liquid on the primary side (the sidewall  211  side) is gathered toward the slit  232  present substantially in the center and collected via the slit  232  by a force of the rotation of the polishing pad  100 . 
     During the polishing processing, the new polishing liquid SLf and the collected used polishing liquid SLu are present in a mixed state in the holding space  201 . However, a part of the polishing liquid in the mixed state is returned to the primary side via the slits  233 . Therefore, in the supplying device  200 , the following is repeated: a part of the polishing liquid in the holding space  201  is output to the secondary side and returned to the primary side via the slits  233  and the polishing liquid on the primary side (the used polishing liquid and the polishing liquid in the holding space  201 ) is introduced in the holding space  201  via the slit  232 . An output amount of the polishing liquid on the secondary side can be adjusted in the same manner as explained in the first embodiment. 
       FIG.  25    is a plan view showing an example of the shape of the supplying device  200 . In this example, the sidewall  211  and the sidewall  212  are respectively have shapes bent near the centers. The sidewall  211  on the primary side has a shape in which the center of the sidewall  211  precedes in the rotating direction Rd of the polishing pad  100 . It is possible to adjust a collection amount of the polishing liquid by adjusting the shape and the angle of the sidewall  211  on the primary side (see  FIG.  25   ), the configuration (the number, disposition, height, and a shape and dimensions) of the slit  231 , and a pressing force by the pressing mechanism  250 . In the example shown in  FIG.  25   , the sidewall  212  on the secondary side has a shape in which the center of the sidewall  212  precedes in the rotating direction Rd of the polishing pad  100 . Consequently, as shown in  FIG.  24   , the polishing liquid in the holding space  201  flows from both ends in the longitudinal direction of the holding space  201  toward the center and accumulates from the center side. Therefore, it is possible to collect the polishing liquid from the center on the primary side of the supplying device  200  and increase an output of the polishing liquid from the center on the secondary side. 
     As the shape of the supplying device  200 , the shapes explained with reference to  FIGS.  19 A to  19 C and  20 A to  20 C  may be adopted. 
       FIG.  26    is a sectional view of the supplying device  200  in which a slit is provided on the secondary side. In this example, a slit is not provided in the sidewall  211  on the primary side and the same slit  231  as the slit  231  shown in  FIGS.  18 A to  18 C  is provided in the sidewall  212  on the secondary side. Collection of the polishing liquid on the primary side is performed by adjusting a pressing force to the sidewall  211  by the pressing mechanism  250 . The used polishing liquid is collected in the holding space  201  from the gap between the sidewall  212  on the primary side and the polishing surface  102 . It is possible to adjust a collection amount of the polishing liquid by adjusting the shape and the angle of the sidewall  211  on the primary side (see  FIG.  25   ) and a pressing force by the pressing mechanism  250 . An output amount of the polishing liquid on the secondary side can be adjusted in the same manner as explained in the first embodiment. 
       FIG.  27    is a sectional view of a supplying device in which slits are provided on the primary side and the secondary side. In this example, the same slits as the slits shown in  FIG.  23    are provided in the sidewall  211  on the primary side and the same slit  231  as the slit  231  shown in  FIGS.  18 A to  18 C  is provided in the sidewall  212  on the secondary side. Adjustment of a collection amount of the polishing liquid on the primary side can be performed in the same manner as explained in the example shown in  FIG.  26   . An output amount of the polishing liquid on the secondary side can be adjusted in the same manner as explained in the first embodiment. 
     A configuration may be adopted in which slits are not provided in both of the sidewalls  211  and  212  on the primary side and the secondary side. In this case, adjustment of a polishing liquid collection amount is performed by adjusting a pressing force to the sidewall  211  by the pressing mechanism  250 . Adjustment of a supply amount of the polishing liquid is performed by adjusting a pressing force to the sidewall  212  by the pressing mechanism  250 . 
     Fourth Embodiment 
       FIG.  28    is a plan view showing a disposition relation among components of the polishing apparatus  10  according to a fourth embodiment.  FIGS.  29  and  30    are sectional views showing examples of a polishing-liquid removing unit.  FIG.  31    is a plan view showing an example of the polishing-liquid removing unit. In this embodiment, the polishing apparatus  10  include a polishing-liquid removing unit  300 . The polishing-liquid removing unit  300  includes a sucking unit  310  and a cleaning unit  320 . The sucking unit  310  and the cleaning unit  320  may be configured as an integrally attached structure or one block ( FIG.  29   ) or may be disposed at an interval as separate blocks ( FIG.  30   ). 
     The sucking unit  310  has generally the same configuration as the configuration of the sucking unit  56  of the polishing-liquid removing unit  50  explained above with reference to  FIGS.  3  and  7   . As shown in  FIG.  28   , the sucking unit  310  has an elongated pad-like shape in a plan view. The sucking unit  310  includes, as shown in  FIG.  29   , a suction space  312  opened on or to the polishing surface  102 , a slit  313  opened in the suction space  312 , and a channel  314  to which a not-shown vacuum source is connected. An end portion on the polishing surface  102  side of the sucking unit  310  is disposed in a degree in contact with the polishing surface  102  or in contact with the polishing liquid on the polishing surface  102 . As in the example shown in  FIGS.  3  and  7   , the sucking unit  310  may include the damming unit  52  that dams the polishing liquid on the polishing surface  102 . 
     As shown in  FIG.  31   , the cleaning unit  320  includes sidewalls (scrapers)  325 ,  326 , and  327  that surround three directions in a plan view. A jetting space  329  is provided to be surrounded by these sidewalls. In  FIG.  31   , for convenience of explanation, a part of components is omitted. Like the damming unit  52  explained above, as the material of the sidewalls  325 ,  326 , and  327 , the same material as the material of the damming unit  52  is desirably selected such that the polishing surface  102  is not scratched and chips of the sidewalls  325 ,  326 , and  327  themselves due to contact with the polishing surface  102  do not remain on the polishing surface  102 . 
     As shown in  FIG.  31   , in the cleaning unit  320 , a sidewall is not provided on the radial direction outer side of the polishing pad  100  and an opening section  328  is formed. The opening section  328  opens the jetting space  329  outward in the radial direction. Cleaning liquid (DIW; HOT DIW) jetted from a cleaning-liquid jetting nozzle  321  and used cleaning liquid SL 2  are discharged outward in the radial direction by a centrifugal force of the rotation of the polishing pad  100  (the polishing table  20 ). A sidewall may be present in a part of the radial-direction outer side end portion in a range not hindering discharge of the polishing liquid. The sidewalls  325 ,  326 , and  327  are disposed in a degree in contact with the polishing surface  102  or slightly not in contact with the polishing surface  102  with a small gap. Depending on a process, heated pure water (HOT DIW) may be used as the cleaning liquid because a polishing rate decreases when the surface temperature of the polishing pad  100  falls. The temperature adjusting unit  60  or  60 A explained above or a temperature adjusting unit of another form may be provided in order to adjust the temperature of the polishing surface  102 . The temperature adjusting unit can be disposed on the downstream side of the polishing-liquid removing unit  300  and on the upstream side of the top ring  30 . The temperature adjusting unit can be disposed on the upstream side or the downstream side of the polishing-liquid supplying unit  40  or  200 . 
     The cleaning unit  320  includes, as shown in  FIG.  29   , the cleaning-liquid jetting nozzle  321  disposed to jet the cleaning liquid toward the jetting space  329  and a channel block  322  including a channel  323  communicating with the cleaning-liquid jetting nozzle  321  to supply the cleaning liquid to the cleaning-liquid jetting nozzle  321 . The cleaning liquid (DIW) is supplied from a not-shown fluid supply source to the cleaning-liquid jetting nozzle  321  via the channel  323 . The cleaning liquid is jetted from the cleaning-liquid jetting nozzle  321  toward the polishing surface  102  in the jetting space  329 . The cleaning-liquid jetting nozzle  321  is mounted such that a jetting angle is orthogonal to or oblique to the polishing surface. The channel block  322  may be formed integrally with the sidewalls  325 ,  326 , and  327  or may be formed separately from the sidewalls  325 ,  326 , and  327 . The used polishing liquid, byproducts, and the like in the groove sections  101  of the polishing surface  102  are removed by the jetted cleaning liquid. 
     In the example shown in  FIG.  31   , nozzle jetting ports  340  of the cleaning-liquid jetting nozzle  321  have an elliptical or fan shape and are disposed to be tilted at a predetermined angle with respect to the longitudinal direction of the cleaning unit  320 . In the nozzle jetting ports having the elliptical or fan shape, a jetting flow rate in the center portion is large and a jetting flow rate in an end portion is small. Therefore, the nozzle jetting ports  340  are disposed such that end portions of the nozzle jetting ports  340  adjacent to each other overlap each other in the longitudinal direction of the cleaning unit  320  such that a uniform flow rate can be obtained in an entire region. As shown in  FIG.  33   , the nozzle jetting ports  340  of the cleaning-liquid jetting nozzle  321  may be directed with an inclination with respect to the polishing surface  102  and to face the radial direction outer side of the polishing surface  102 . In this case, the cleaning liquid (DIW) and the used polishing liquid are easily discharged to the outer side from the opening section  328 . In the example shown in  FIG.  32   , the nozzle jetting ports  340  of the cleaning-liquid jetting nozzle  321  has an elliptical or fan shape. The nozzle jetting ports  340  are disposed in parallel to the longitudinal direction of the cleaning unit  320 . The nozzle jetting ports  340  are alternately disposed side by side such that the end portions of the nozzle jetting ports  340  adjacent to each other overlap each other in the longitudinal direction of the cleaning unit  320 . 
       FIGS.  34 A to  34 C  are perspective views showing configuration examples of the polishing-liquid removing unit.  FIG.  34 A  is the perspective view viewed from the outer side of the polishing pad  100 .  FIG.  34 B  is the perspective view of a state in which a cover of the sucking unit  310  is removed.  FIG.  34 C  is the perspective view viewed from the center side of the polishing surface  102 . In the configuration examples shown in  FIGS.  34 A to  34 C , in the cleaning unit  320 , the sidewalls  325 ,  326 , and  327  are disposed on the upstream side and the downstream side in the rotating direction of the polishing table  20  and on the center side of the polishing table  20 . The channel block  322  is disposed above a space surrounded by the sidewalls  325 ,  326 , and  327 . The jetting space  329  is formed below the channel block  322 . The jetting space  329  is surrounded by the sidewalls  325 ,  326 , and  327  and the channel block  322 . On the outer circumference side of the polishing table  20  of the cleaning unit  320 , a sidewall is not provided and the opening section  328  is provided. The jetting space  329  is opened from the opening section  328  on the outer circumference side of the polishing table  20 . A pipe  324  is coupled to the channel block  322 . The channel  323  is provided in the pipe  324 . The channel  323  is connected to the nozzle jetting ports  340  ( FIG.  30   ) of the cleaning-liquid jetting nozzle  321  ( FIG.  29   ). 
     In the examples shown in  FIGS.  34 A to  34 C , the sucking unit  310  includes a suction block  311  fixed to an arm  350  (see  FIG.  28   ). The suction space  312  ( FIGS.  29  and  30   ) is formed in the suction block  311 . A pipe  316  is disposed on the arm  350 . One end of the pipe  316  is connected to a not-shown vacuum source. The other end is connected to the suction block  311  via a coupling block  315 . The channel  314  extends to the pipe  316 , the coupling block  315 , and the suction block  311 . The channel  314  is connected to the slit  313  ( FIGS.  29  and  30   ) opened in the suction space  312 . A cover  318  is attached to an upper part of the suction block  311  to cover the coupling block  315  and the pipe  316 . Like the damming unit  52  explained above, as the material of the suction block  311 , the same material as the material of the damming unit  52  is desirably selected such that the polishing surface  102  is not scratched and chips of the sucking unit  310  itself due to contact with the polishing surface  102  do not remain on the polishing surface  102 . 
     As shown in  FIG.  28   , the polishing-liquid removing unit  300  (the cleaning unit  320  and the sucking unit  310 ) is attached to the arm  350 , which is capable of swinging and moving up and down, and can be pressed against the polishing surface  102  of the polishing pad  100 . The arm  350  is attached to a column on the outside of the polishing table  20 . For example, a cylinder can be used as a lifting and lowering mechanism for moving the arm  350  up and down. In this case, it is possible to control a pressing pressure against the polishing pad  100  by changing, with a regulator (a proportional control valve or the like), the pressure of driving fluid supplied to the cylinder. Further, it is also possible to cancel the weight (own weight) of a mechanism attached to the arm or it is also possible to reduce the pressing pressure to 0. The lifting and lowering mechanism is not limited to the cylinder. A mechanism by power of a motor and any other mechanisms can be adopted. The pressing mechanisms in the second and third embodiments may be used. The cleaning unit  320  and the sucking unit  310  may be attached to separate arms capable of swinging and moving up and down. 
     With such a polishing-liquid removing unit  300 , the cleaning liquid is jetted onto the polishing surface from the cleaning-liquid jetting nozzle  321  in the jetting space  329  of the cleaning unit  320 . The used polishing liquid and byproducts on the polishing surface are washed away by the cleaning liquid. The cleaning liquid is discharged outward in the radial direction via the opening section  328  by a centrifugal force of the rotation of the polishing table. Subsequently, the sucking unit  310  removes, with suction, the cleaning liquid present in the groove sections (the pad grooves; the porous portions) on the polishing surface where discharge by the centrifugal force is difficult in the cleaning unit  320 . Consequently, it is possible to remove the byproducts and the used polishing liquid on the polishing surface. It is possible to supply only new polishing liquid onto the polishing surface with the polishing-liquid supplying mechanism (the polishing-liquid supply nozzle  40  or  200 ) disposed behind the sucking unit  310 . As a result, it is possible to prevent defects of the substrate and improve polishing quality (a polishing rate, in-plane uniformity, and the like). 
     In this embodiment, as shown in  FIG.  28   , the dresser  90  and the atomizer  94  may be provided. The cleaning unit  320  of the polishing-liquid removing unit  300  may be used as an atomizer and the separate atomizer  94  may be omitted. The dresser  90  and the atomizer  94  may be omitted. In the above explanation, a sidewall is not provided on the radial-direction outer side end face of the cleaning unit  320 . However, a sidewall may be provided on the radial-direction outer side end face as well such that the entire circumference of the jetting space  329  is surrounded by the sidewalls. 
     Fifth Embodiment 
       FIG.  35    is a perspective view showing a disposition relation among components of a polishing apparatus according to a fifth embodiment.  FIG.  36    is a plan view of a polishing-liquid removing unit for explaining discharge of cleaning liquid. In this embodiment, the polishing-liquid removing unit  300  is configured in a shape conforming to the external shape of the top ring  30  and disposed on the outer side of the top ring  30 . The polishing-liquid removing unit  300  in this embodiment is the same as the polishing-liquid removing unit  300  in the fourth embodiment except that the cleaning unit  320  and the sucking unit  310  are formed in arcuate shapes. As in the fourth embodiment, the opening section  328  is provided at the end portion on the radial direction outer side of the cleaning unit  320  ( FIG.  36   ). Therefore, as shown in  FIG.  36   , the cleaning liquid jetted into the jetting space  329  of the cleaning unit  320  is discharged to the outer side of the polishing surface  102  via the opening section  328  as indicated by an arcuate arrow. In this embodiment as well, the cleaning liquid is guided to the radial direction outer side in the jetting space  329  by the centrifugal force of the polishing table  20 , and the nozzle jetting ports  340  of the cleaning-liquid jetting nozzle  321  may be directed with an inclination with respect to the polishing surface  102  and to face the radial direction outer side of the polishing surface  102 , as shown in  FIG.  33   . In this case, the cleaning liquid (DIW) and the used polishing liquid are easily discharged to the outer side from the opening section  328 . A plane shape of the nozzle jetting ports  340  can be formed in the same shape as the shape shown in  FIGS.  31  and  32   . 
       FIGS.  37  and  38    are perspective views showing examples of an attachment structure of the polishing-liquid removing unit. In the example shown in  FIG.  37   , the polishing-liquid removing unit  300  is attached to the supporting arm  34  of the top ring  30  via a lifting and lowering guide  35  and a bracket  37 . One end of a shaft of the lifting and lowering guide  35  is fixed to the sucking unit  310  of the polishing-liquid removing unit  300 . The other end of the shaft of the lifting and lowering guide  35  is coupled to a rod of a cylinder  36 . A force of the polishing-liquid removing unit  300  being pressed against the polishing surface  102  is adjusted by extension and retraction of the rod of the cylinder  36 . One end of the shaft of the lifting and lowering guide  35  may be fixed to the cleaning unit  320  of the polishing-liquid removing unit  300  or may be fixed to both of the cleaning unit  320  and the sucking unit  310 . 
     In the example shown in  FIG.  38   , the polishing-liquid removing unit  300  is fixed to a rotating/lifting and lowering shaft  31   a  of the top ring  30  via a bracket  37   a . The bracket  37   a  can be fixed to the cleaning unit  320  and/or the sucking unit  310 . By coupling the bracket  37   a  and the rotating/lifting and lowering shaft  31   a  via a rotary bearing and providing a whirl stop mechanism, the rotation of the rotating/lifting and lowering shaft  31   a  is prevented from being transmitted to the bracket  37   a . With this configuration, the polishing-liquid removing unit  300  fixed to the bracket  37   a  is lifted and lowered in synchronization with lifting and lowering of the rotating/lifting and lowering shaft  31   a . Consequently, the polishing-liquid removing unit  300  is pressed against the polishing surface  102 . 
     According to this embodiment, similar functions and effects as those in the fourth embodiment are achieved. Further, the used polishing liquid and the byproducts immediately after the polishing treatment can be collected by the polishing-liquid removing unit  300 . Since the polishing-liquid removing unit  300  has the shape conforming to the external shape of the top ring  30 , it is possible to achieve space saving of the polishing-liquid removing unit  300 . 
     As in the fourth embodiment, the opening section  328  may be provided at the radial-direction outer side end portion of the cleaning unit  320  or the entire circumference of the cleaning unit  320  may be surrounded by the sidewalls. In this embodiment, as in the example shown in  FIG.  28   , the dresser  90  and the atomizer  94  may be provided. The cleaning unit  320  of the polishing-liquid removing unit  300  may be used as an atomizer and the separate atomizer  94  may be omitted. The dresser  90  and the atomizer  94  may be omitted. 
     Sixth Embodiment 
       FIG.  39    is a plan view showing a disposition relation among components of a polishing apparatus according to a sixth embodiment. In this example, the polishing-liquid removing unit  300  is provided in the polishing apparatus in the second embodiment. The polishing-liquid removing unit  300  may have the same configuration as the configuration of the polishing-liquid removing unit  50  explained above or the polishing-liquid removing unit  300  according to the fourth or fifth embodiment or may have another configuration. Instead of the supplying device  200  in the second embodiment, the slurry supplying device described in Japanese Patent Application Laid-Open No. H11-114811 (U.S. Pat. No. 6,336,850) may be combined with the polishing-liquid removing unit  300  according to the fourth or fifth embodiment. The entire disclosure including the specification, the claims, the drawings, and the abstract of Japanese Patent Application Laid-Open No. H11-114811 (U.S. Pat. No. 6,336,850) is incorporated in this application by reference. 
     The polishing-liquid removing unit  300  is desirably disposed in the rear (on the downstream side) of the top ring  30  and in the front (on the upstream side) of the supplying device  200  (the slurry supplying device). According to this embodiment, after the used polishing liquid is removed by the polishing-liquid removing unit  300 , the used polishing liquid is discharged to the outside of the polishing pad  100  by the sidewall  211  on the primary side of the supplying device  200 . Therefore, it is possible to further suppress the used polishing liquid from mixing in the polishing liquid output from the secondary side of the supplying device  200 . 
     In this embodiment, as in the example shown in  FIG.  28   , the dresser  90  and the atomizer  94  may be provided. The cleaning unit  320  of the polishing-liquid removing unit  300  may be used as an atomizer and the separate atomizer  94  may be omitted. The dresser  90  and the atomizer  94  may be omitted. 
     The cleaning unit of the polishing-liquid removing unit  300  may be omitted. In this case, it is possible to reduce an amount of use of the polishing liquid by setting a suction pressure and a pressing force of the sucking unit  310  to an optimum pressure for removing only the polishing liquid (abrasive grains) ineffective for polishing present in the groove sections (the pad grooves; the porous portions) without completely removing the used polishing liquid on the polishing surface. The polishing liquid not removed by the sucking unit  310  is discharged on the primary side of the supplying device  200 . 
     Seventh Embodiment 
       FIG.  40    is a plan view showing a disposition relation of components of a polishing apparatus according to a seventh embodiment. In this example, a temperature adjusting unit  400  is provided in the polishing apparatus in the second or third embodiment. The temperature adjusting unit  400  may have the same configuration as the configuration of the temperature adjusting unit  60  ( FIG.  4    and the like) and the temperature adjusting unit  60 A ( FIG.  8   ) explained above or may have another configuration. The temperature adjusting unit  400  is desirably disposed in the rear (on the downstream side) of the top ring  30  and in the front (on the upstream side) of the supplying device  200 . As explained above, the temperature adjusting unit  400  may be controlled based on temperature detected by the temperature sensor  68 . According to this embodiment, since the temperature adjustment of the polishing surface  102  can be performed, it is possible to improve polishing quality. 
     When the temperature adjusting unit  400  is provided in the polishing apparatus in the second embodiment, the polishing-liquid removing unit  300  explained above may be further provided. In this case, the supplying device  200 , the top ring  30 , the polishing-liquid removing unit  300 , and the temperature adjusting unit  400  are desirably disposed in this order. In this case, the temperature adjusting unit  400  can adjust the temperature of the polishing surface  102  in a state in which the polishing liquid, which could be a heat insulating layer, is removed. It is possible to improve efficiency of the temperature adjustment of the polishing surface  102 . 
     The supplying device  200 , the temperature adjusting unit  400 , the top ring  30 , and the polishing-liquid removing unit  300  may be disposed in this order. In this case, the temperature of the polishing surface can be adjusted to temperature optimum for polishing immediately before the polishing treatment. 
     In this embodiment, as in the example shown in  FIG.  28   , the dresser  90  and the atomizer  94  may be provided. The cleaning unit  320  of the polishing-liquid removing unit  300  may be used as an atomizer and the separate atomizer  94  may be omitted. The dresser  90  and the atomizer  94  may be omitted. 
     At least the following modes can be grasped from the embodiments. 
     According to a first mode, there is provided a polishing apparatus that performs polishing an object to be polished using a polishing pad having a polishing surface, the polishing apparatus including: a polishing table for supporting the polishing pad, the polishing table being configured to be rotatable; a substrate holding unit configured to hold the object to be polished and press the object to be polished against the polishing pad; a supplying device for supplying polishing liquid to the polishing surface in a state in which the supplying device is pressed against the polishing pad; and a pressing mechanism configured to press the supplying device against the polishing pad, wherein the supplying device includes: a sidewall pressed against the polishing surface, the sidewall including a first wall on an upstream side in a rotating direction of the polishing table and a second wall on a downstream side in the rotating direction of the polishing table; and a holding space surrounded by the sidewall and opened to the polishing surface, the holding space holding the polishing liquid and supplying the polishing liquid to the polishing surface, and the pressing mechanism configured to respectively adjust pressing forces to the first wall and the second wall. 
     According to this mode, it is possible to respectively adjust the pressing forces for pressing the sidewalls on the upstream side and the downstream side of the supplying device against the polishing surface. Therefore, it is possible to separately adjust functions of the sidewalls on the upstream side and the downstream side. It is possible to press, according to desired functions, the sidewalls on the upstream side and the downstream side with optimum pressing forces. The desired functions include a function of adjusting discharge and collection of used polishing liquid by the supplying device, a function of adjusting the supply of the polishing liquid from the supplying device, a function of adjusting rates of the discharge and the collection of the used polishing liquid, a function of adjusting collection amounts of the polishing liquid in places of the supplying device, and a function of adjusting supply amounts of the polishing liquid from places in the longitudinal direction of the supplying device. 
     For example, it is possible to discharge the used polishing liquid to the outside of the polishing pad by adjusting the pressing force to the sidewall on the upstream side. Consequently, the used polishing liquid is suppressed from mixing in the polishing liquid supplied from the supplying device. It is possible to supply substantially only new polishing liquid. It is possible to collect at least a part of the used polishing liquid in the holding space via the sidewall on the upstream side and reuse the used polishing liquid by adjusting the pressing force of the sidewall on the upstream side of the supplying device against the polishing surface. Consequently, it is possible to reduce a consumption amount of the polishing liquid. Depending on a process, it is possible to suppress defects of a substrate and improve a polishing rate by reusing the polishing liquid. It is possible to supply the polishing liquid from the supplying device to a substrate holding unit by a necessary amount and in a necessary region by adjusting the pressing force to the sidewall on the downstream side. Consequently, it is possible to suppress excessive supply of the polishing liquid to the polishing surface. It is possible to reduce a consumption amount of the polishing liquid. 
     According to a second mode, in the polishing apparatus according to the first mode, the pressing mechanism includes a plurality of pressing units configured to press the supplying device and is configured to be capable of respectively adjusting the pressing forces to the first wall and the second wall by controlling pressing forces of the pressing units. The pressing units can be, for example, cylinder devices driven by fluid or rods driven by power of solenoids, other motors, or the like. 
     According to this mode, it is possible to accurately perform the adjustment of the pressing forces to the first wall and the second wall by controlling the pressing forces of the pressing units. It is possible to press, according to desired functions, parts of the supplying device with optimum pressing forces by controlling the pressing forces of the pressing units. 
     According to a third mode, in the polishing apparatus according to the second mode, the pressing mechanism respectively adjusts the pressing forces to the first wall and the second wall to thereby discharge, with the first wall, used polishing liquid to an outside of the polishing pad and adjust, with the second wall, an amount of the polishing liquid on the polishing pad supplied from the holding space to the substrate holding unit side. 
     According to this mode, it is possible to discharge the used polishing liquid to the outside of the polishing pad by adjusting the pressing force to the sidewall on the upstream side. Consequently, the used polishing liquid is suppressed from mixing in the polishing liquid supplied from the supplying device. It is possible to supply substantially only new polishing liquid. Note that a part of the used polishing liquid may be collected. It is possible to supply the polishing liquid from the supplying device to the substrate holding unit by a necessary amount and in a necessary region by adjusting the pressing force to the sidewall on the downstream side. Consequently, it is possible to suppress excessive supply of the polishing liquid to the polishing surface. It is possible to reduce a consumption amount of the polishing liquid. 
     According to a fourth mode, in the polishing apparatus according to the second mode, the pressing mechanism respectively adjusts the pressing forces to the first wall and the second wall by the pressing mechanism to thereby collect, with the first wall, at least a part of used polishing liquid in the holding space and adjust, with the second wall, the amount of the polishing liquid on the polishing pad supplied from the holding space to the substrate holding unit side. 
     According to this mode, it is possible to supply the polishing liquid from the supplying device to the substrate holding unit by a necessary amount and in a necessary region by adjusting the pressing force of the sidewall on the downstream side of the supplying device against the polishing surface. Consequently, it is possible to suppress excessive supply of the polishing liquid to the polishing surface. It is possible to reduce a consumption amount of the polishing liquid. It is possible to collect at least a part of the used polishing liquid in the holding space via the sidewall on the upstream side and reuse the used polishing liquid by adjusting the pressing force of the sidewall on the upstream side of the supplying device against the polishing surface. Consequently, it is possible to further reduce a consumption amount of the polishing liquid. Depending on a process, it is possible suppress defects of a substrate and improve a polishing rate by reusing the polishing liquid. 
     According to a fifth mode, in the polishing apparatus according to any one of the first to fourth modes, the first wall includes one or a plurality of first opening sections for collecting the polishing liquid on the polishing surface. According to this mode, it is possible to improve flexibility of adjustment of a collection amount of the polishing liquid by collecting the polishing liquid from the first opening sections. 
     According to a sixth mode, in the polishing apparatus according to the fifth mode, each of the one or plurality of first opening sections has any shape and dimensions and is disposed in any position of the first wall. According to this mode, it is possible to further improve the flexibility of the adjustment of the collection amount of the polishing liquid by providing the first opening sections by any number, in any shapes and dimensions, and in any disposition. 
     According to a seventh mode, in the polishing apparatus according to any one of first to sixth modes, the first wall includes one or a plurality of second opening sections for supplying the polishing liquid from the holding space to the polishing surface. According to this mode, the polishing liquid in the holding space is supplied from the second opening sections onto the polishing surface and collected in the holding space again together with used polishing liquid. Consequently, it is possible to desirably mix new polishing liquid and the used polishing liquid. 
     According to an eighth mode, in the polishing apparatus according to the seventh mode, each of the one or plurality of second opening sections has any shape and dimensions and is disposed in any position of the first wall. According to this mode, it is possible to flexibly adjust a supply flow rate of the polishing liquid to the side of the first wall by providing the second opening sections by any number, in any shapes and dimensions, and in any disposition. 
     According to a ninth mode, in the polishing apparatus according to the eighth mode, the first wall includes the plurality of second opening sections provided at different heights. According to this mode, it is possible to adjust a supply flow rate of the polishing liquid to the side of the first wall from the holding space according to a position in a polishing pad radial direction, for example, by changing the heights of the second opening sections according to the position in the polishing pad radial direction. 
     According to a tenth mode, in the polishing apparatus according to any one of the first to ninth modes, the second wall includes one or a plurality of third opening sections for supplying the polishing liquid from the holding space of the supplying device to the substrate holding unit side. According to this mode, it is possible to improve flexibility of adjustment of a supply amount of the polishing liquid from the supplying device. 
     According to an eleventh mode, in the polishing apparatus according to the tenth mode, each of the one or plurality of third opening sections has any shape and dimensions and is disposed in any position of the second wall. According to this mode, it is possible to further improve the flexibility of the adjustment of the supply flow rate of the polishing liquid from the supplying device by providing the third opening sections by any number, in any shapes and dimensions, and in any disposition. 
     According to a twelfth mode, in the polishing apparatus according to the eleventh mode, the second wall includes the plurality of third opening sections provided at different heights. According to this mode, it is possible to adjust a supply flow rate of the polishing liquid according to a position in the polishing pad radial direction, for example, by changing the heights of the third opening sections according to the position in the polishing pad radial direction. 
     According to a thirteenth mode, in the polishing apparatus according to any one of the first to twelfth modes, the second wall includes a portion preceding other portions in the rotating direction of the polishing table in a plan view. A supply amount of the polishing liquid from the preceding portion is larger than a supply amount of the polishing liquid from the other portions. According to this mode, by causing a portion in the second wall from which the polishing liquid is desired to be actively fed (a portion from which a supply flow rate of the polishing liquid is desired to be increased) to precede in the rotating direction, the polishing liquid starts to accumulate from the preceding portion in the holding space whereby it is possible to feed a larger amount of the polishing liquid from the preceding portion. 
     According to a fourteenth mode, in the polishing apparatus according to the thirteenth mode, in a plan view, any end portion side in a longitudinal direction of the second wall precedes other portions in the rotating direction of the polishing table. According to this mode, since the polishing liquid flows to the preceding end portion side from an opposite side of the preceding end portion side, it is possible to accumulate the polishing liquid from the preceding end portion side. Consequently, it is possible to increase a supply flow rate of the polishing liquid from any end portion side in the longitudinal direction. 
     According to a fifteenth mode, in the polishing apparatus according to the thirteenth mode, in a plan view, a center side in the longitudinal direction of the second wall precedes other portions in the rotating direction of the polishing table. According to this mode, since the polishing liquid flows from both end portion sides to the center side, it is possible to accumulate the polishing liquid from the center side. Consequently, it is possible to increase a supply flow rate of the polishing liquid from the center side in the longitudinal direction. It is possible to feed a larger amount of the polishing liquid to the center of an object to be polished. 
     According to a sixteenth mode, in the polishing apparatus according to any one of the first to fifteenth modes, the pressing mechanism further includes a pressing-posture adjusting mechanism for adjusting a posture of the supplying device. According to this mode, the supplying device can be set in parallel to the polishing surface by the pressing-posture adjusting mechanism. 
     According to a seventeenth mode, in the polishing apparatus according to any one of the first to sixteenth modes, the pressing mechanism is configured to be capable of pressing the supplying device with different pressing forces in different parts in a longitudinal direction of the supplying device and/or different parts in a width direction of the polishing table. According to this mode, places in directions of the supplying device can be pressed with different pressing forces by the pressing mechanism. Therefore, it is possible to more flexibly control blocking abilities of the polishing liquid in places of the first wall and supply amounts of the polishing liquid from places of the second wall. 
     According to an eighteenth mode, in the polishing apparatus according to any one of the first to seventeenth modes, the polishing apparatus further includes a polishing-liquid removing unit configured to remove used polishing liquid, the polishing-liquid removing unit being disposed between the substrate holding unit and the supplying device in the rotating direction of the polishing table. According to this mode, after the used polishing liquid is removed by the polishing-liquid removing unit, the used polishing liquid can be further discharged by the supplying device. Therefore, it is possible to more completely perform the removal of the used polishing liquid. 
     According to a nineteenth mode, in the polishing apparatus according to any one of the first to eighteenth modes, the polishing apparatus further includes a temperature adjusting unit configured to adjust temperature of the polishing surface. According to this mode, it is possible to supply new polishing liquid from the supplying device in a state in which the temperature of the polishing pad is adjusted by the temperature adjusting unit. Therefore, it is possible to further suppress defects of the substrate and further improve the polishing rate. 
     According to a twentieth mode, there is provided a polishing method for rotating a polishing table attached with a polishing pad and pressing the object to be polished held by a substrate holding unit against the polishing pad to polish the object to be polished, the polishing method including: pressing a supplying device against the polishing surface, the supplying device being surrounded by a sidewall and including a holding space for the polishing liquid opened to a polishing surface of the polishing pad; bringing the polishing liquid into contact with the polishing surface of the polishing pad in the holding space; and respectively adjusting, with a pressing mechanism, pressing forces of sidewalls on an upstream side and a downstream side in a rotating direction of the polishing table against the polishing surface to thereby discharge, with the sidewall on the upstream side, used polishing liquid to an outside of the polishing pad and/or collect at least a part of the used polishing liquid in the holding space and adjust, with the sidewall on the downstream side, an amount of the polishing liquid on the polishing pad supplied from the holding space to the substrate holding unit side. According to this mode, similar functions and effects as those in the first mode are achieved. 
     According to a twenty-first mode, in the polishing method according to the twentieth mode, the polishing liquid is supplied to a desired portion of the polishing surface by a desired amount by adjusting the pressing force of the sidewall on the downstream side against the polishing surface. Consequently, it is possible to suppress excessive supply of the polishing liquid to the polishing surface while maintaining reliability of polishing treatment. 
     According to a twenty-second mode, in the polishing method according to the twentieth or twenty-first mode, the polishing liquid supplied from the holding space to the substrate holding unit side is adjusted to be the polishing liquid mainly present in groove sections of the polishing surface by adjusting the pressing force of the sidewall on the downstream side against the polishing surface. It is possible to reduce a consumption amount of the polishing liquid by performing the polishing treatment with the polishing liquid in the groove sections of the polishing surface. 
     The embodiments of the present invention are explained above. However, the embodiments of the invention explained above are for facilitating understanding of the present invention and do not limit the present invention. It goes without saying that the present invention can be changed and improved without departing from the gist of the present invention and equivalents of the present invention are included in the present invention. Any combinations of the embodiments and the modifications are possible in a range in which at least a part of the problems described above can be solved or a range in which at least a part of the effects described above can be achieved. Any combinations or omission of the constituent elements described in the claims and the specification are possible. 
     The present application claims the benefit of priority to Japanese patent application No. 2018-147917 filed on Aug. 6, 2018. The entire disclosure of Japanese patent application No. 2018-147917 filed on Aug. 6, 2018 including specification, claims, drawings and summary is incorporated herein by reference in its entirety. The entire disclosure of Japanese Patent Application Laid-Open No. 2001-150345 (Patent Literature 1), Japanese Patent No. 4054306 (Patent Literature 2), Japanese Patent Application Laid-Open No. 2008-194767 (Patent Literature 3), and United States Patent Publication No. 2016/0167195 (Patent Literature 4) including specification, claims, drawings and summary are incorporated herein by reference in their entirety. 
     REFERENCE SIGNS LIST 
     
         
           10  polishing apparatus 
           20  polishing table 
           30  top ring 
           40  polishing-liquid supply nozzle 
           50  polishing-liquid removing unit 
           60  damming unit 
           56  sucking unit 
           57  slit 
           58  channel 
           60 ,  60 A temperature adjusting unit 
           62  gas jetting nozzle 
           62 A heat exchanger 
           70  control unit 
           100  polishing pad 
           102  polishing surface 
           200  supplying device 
           201  holding space 
           210 ,  211 ,  212  sidewall 
           250  pressing mechanism 
           251  cylinder device 
           251   a  cylinder 
           252  pressing-posture adjusting mechanism 
           300  polishing-liquid removing unit 
           310  sucking unit 
           320  cleaning unit 
         SL polishing liquid 
         Wk substrate