Patent Publication Number: US-2021187691-A1

Title: Substrate processing apparatus and substrate processing method

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2019-233131, filed on Dec. 24, 2019, the entire contents of which are incorporated herein by reference. 
     TECHNICAL FIELD 
     The present disclosure relates to a substrate processing apparatus and a substrate processing method. 
     BACKGROUND 
     A substrate processing apparatus disclosed in Patent Document 1 includes a holding part for holding a substrate horizontally, a rotating part for rotating the substrate, a polishing brush for polishing the upper surface of the substrate, a moving part for scanning the polishing brush in the radial direction of the substrate in a state in which the polishing brush is pressed against the upper surface of the substrate, a liquid supply part for supplying a cleaning liquid to the upper surface of the substrate, and a controller for controlling the rotating part, the moving part, and the liquid supply part. As the polishing brush moves outward from inward of the substrate in the radial direction, the scanning speed of the polishing brush decreases and the rotation speed of the substrate also decreases. 
     PRIOR ART DOCUMENTS 
     Patent Document 
     Patent Document 1: Japanese laid-open publication No. 2019-055441 
     SUMMARY 
     According to one embodiment of the present disclosure, there is provided a substrate processing apparatus including: a holding part configured to hold a substrate; a rotating part configured to rotate the holding part to rotate the substrate together with the holding part; a liquid supply part configured to supply a cleaning liquid to a main surface of the substrate; a polishing head configured to polish the main surface of the substrate; a moving part configured to scan the polishing head in a radial direction of the substrate while pressing the polishing head against the main surface of the substrate; and a controller configured to control the rotating part, the liquid supply part, and the moving part, wherein the controller sets a division line that divides the main surface of the substrate into a plurality of areas in the radial direction of the substrate, controls the liquid supply part to supply the cleaning liquid to each of the plurality of areas, and controls the moving part to scan the polishing head for each of the plurality of areas in a state in which a subsequent supply of the cleaning liquid is stopped. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the present disclosure, and together with the general description given above and the detailed description of the embodiments given below, serve to explain the principles of the present disclosure. 
         FIG. 1A  is a sectional view showing a state of a substrate processing apparatus at the time of polishing according to an embodiment. 
         FIG. 1B  is a sectional view showing a state of the substrate processing apparatus of  FIG. 1A  at the time of cleaning. 
         FIG. 2  is a sectional view showing an example of a structure of a substrate. 
         FIG. 3  is a perspective view showing an example of a polishing head. 
         FIG. 4  is a flowchart showing a substrate processing method according to an embodiment. 
         FIG. 5  is a plan view showing an example of polishing of  FIG. 4 . 
         FIG. 6  is a plan view showing an example of a division line that divides a first main surface of the substrate into a plurality of areas in a radial direction. 
         FIG. 7  is a graph showing a relationship between a friction coefficient between the polishing head and the substrate and a distance from the center point of the first main surface of the substrate. 
         FIG. 8  is a table showing an example of set values used in the polishing of  FIG. 4 . 
         FIG. 9  is a graph showing a relationship between a haze value after polishing in Examples 1 and 2 and Reference Example 1 and a distance from the center point of the first main surface of the substrate. 
     
    
    
     DETAILED DESCRIPTION 
     Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. Throughout the drawings, in some cases, the same or corresponding configurations will be denoted by the same reference numerals and explanation thereof will not be repeated. In the present disclosure, an X-axis direction, a Y-axis direction, and a Z-axis direction are orthogonal to each another. The X-axis direction and the Y-axis direction are the horizontal direction, and the Z-axis direction is the vertical direction. In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the present disclosure. However, it will be apparent to one of ordinary skill in the art that the present disclosure may be practiced without these specific details. In other instances, well-known methods, procedures, systems, and components have not been described in detail so as not to unnecessarily obscure aspects of the various embodiments. 
     As shown in  FIGS. 1A and 1B , a substrate processing apparatus  10  includes a holding part  20 , a rotating part  25 , a liquid supply part  30 , a polishing head  70 , a moving part  80 , and a controller  90 . The holding part  20  holds a substrate W horizontally. The rotating part  25  rotates the holding part  20  to rotate the substrate W together with the holding part  20 . The liquid supply part  30  supplies a cleaning liquid to a first main surface Wa of the substrate W. The polishing head  70  polishes the first main surface Wa of the substrate W. The moving part  80  scans the polishing head  70  in the radial direction of the substrate W in a state in which the polishing head  70  is pressed against the first main surface Wa of the substrate W. The controller  90  controls the rotating part  25 , the liquid supply part  30 , and the moving part  80 . The substrate processing apparatus  10  further includes a housing  11  and a recovery cup  12 . Hereinafter, each configuration will be described. 
     The holding part  20  holds the substrate W horizontally. When the substrate W is held horizontally, the X-axis direction and the Y-axis direction are parallel to the first main surface Wa of the substrate W. The X-axis direction is a movement direction of the polishing head  70 . 
     As shown in  FIG. 2 , the substrate W includes, for example, an underlying substrate W 1  and a film W 2  formed on a surface of the underlying substrate W 1 . The underlying substrate W 1  is, for example, a semiconductor substrate or a glass substrate. The semiconductor substrate is a silicon wafer, a compound semiconductor wafer, or the like. 
     The film W 2  is formed on the surface of the underlying substrate W 1  by a CVD (chemical vapor deposition) method, an ALD (atomic layer deposition) method, or the like. The film W 2  is an amorphous silicon film, a polycrystalline silicon film, a silicon oxide film, a silicon nitride film, or the like. The film W 2  may be a TEOS film. The TEOS film is a silicon oxide film formed by using TEOS (tetraethylorthosilicate). The film W 2  may have either a single-layer structure or a multi-layer structure. 
     The substrate W has the first main surface Wa and a second main surface Wb opposite to the first main surface Wa. The first main surface Wa is a surface to be polished by the polishing head  70 . On the other hand, the second main surface Wb is a surface to be patterned by a photolithography method, an etching method, or the like after the first main surface Wa is polished. The film W 2  on the second main surface Wb is patterned. 
     Although not shown, an exposure machine forms an exposure pattern on the second main surface Wb of the substrate W in a state in which the first main surface Wa of the substrate W is oriented downward and the substrate W is placed on a stage. The first main surface Wa is mounted on the exposure machine in a state in which the first main surface Wa is previously polished by the polishing head  70  to remove deposits and scratches. Since adsorption distortion of the first main surface Wa is small when the first main surface Wa is mounted on the exposure machine, distortion of the second main surface Wb is also small so that defocus can be reduced, thereby improving the pattern processing accuracy. 
     The holding part  20  holds the substrate W horizontally in the state in which the first main surface Wa, which is a polishing target, is oriented upward. The holding part  20  is, for example, a mechanical chuck that holds the outer circumference of the substrate W. However, the holding part  20  may be a vacuum chuck or an electrostatic chuck, and may hold a lower surface of the substrate W. 
     The rotating part  25  is a rotary motor or the like, and rotates the holding part  20  around a vertical rotary shaft  26 . The rotating part  25  rotates the holding part  20  while the substrate W is held by the holding part  20 . As a result, the substrate W is rotated. 
     The liquid supply part  30  supplies the cleaning liquid to the first main surface Wa of the substrate W while the substrate W is held by the holding part  20 . As the cleaning liquid, for example, DIW (deionized water) is used. The number of cleaning liquids may be plural. A chemical liquid and a rinsing liquid may be used in order as the cleaning liquid. The liquid supply part  30  includes, for example, a first nozzle  31  and a second nozzle  41 . 
     The first nozzle  31  supplies the cleaning liquid to the center of the first main surface Wa of the substrate W while the substrate W is rotating. The cleaning liquid soaks and spreads over the entire first main surface Wa of the substrate W by virtue of a centrifugal force, and is dropped from the peripheral edge of the substrate W. The first nozzle  31  is connected to a liquid source  33  via a pipe  32 . An opening/closing valve  35  and a flow rate controller  36  are installed in the pipe  32 . When the opening/closing valve  35  opens a flow path of the pipe  32 , the cleaning liquid is supplied from the liquid source  33  to the first nozzle  31 , and is discharged from the first nozzle  31 . A discharge amount of the cleaning liquid is controlled by the flow rate controller  36 . On the other hand, when the opening/closing valve  35  closes the flow path of the pipe  32 , the supply of the cleaning liquid from the liquid source  33  to the first nozzle  31  is stopped to stop the discharge of the cleaning liquid. 
     The second nozzle  41  moves in the radial direction of the substrate W while the substrate W is rotating, and supplies the cleaning liquid over the entire first main surface Wa of the substrate W in the radial direction. The liquid supply part  30  includes a moving device  51  configured to move the second nozzle  41  in the radial direction of the substrate W. The second nozzle  41  is a two-fluid nozzle in which the cleaning liquid is pulverized with a gas such as a N 2  gas, atomized, and sprayed. A cleaning power of the cleaning liquid can be improved. 
     Similarly to the first nozzle  31 , the second nozzle  41  is connected to a liquid source  43  via a pipe  42 . An opening/closing valve  45  and a flow rate controller  46  are installed in the pipe  42 . Further, the second nozzle  41  is connected to a gas source  53  via a pipe  52 . An opening/closing valve  55  and a flow rate controller  56  are installed in the pipe  52 . When the opening/closing valve  55  opens a flow path of the pipe  52 , a gas is supplied from the gas source  53  to the second nozzle  41 , and is discharged from the second nozzle  41 . A discharge amount of the gas is controlled by the flow rate controller  56 . On the other hand, when the opening/closing valve  55  closes the flow path of the pipe  52 , the supply of the gas from the gas source  53  to the second nozzle  41  is stopped to stop the discharge of the gas. 
     Various kinds of fluids discharged from the liquid supply part  30  are collected in the recovery cup  12 . The recovery cup  12  accommodates the holding part  20  and the substrate W held by the holding part  20  therein, and prevents droplets from scattering from the substrate W. A drainage pipe and an exhaust pipe (not shown) are provided in a bottom wall of the recovery cup  12 . The drain pipe discharges the cleaning liquid, and the exhaust pipe discharges the gas. 
     As shown in  FIG. 1A , the polishing head  70  is brought into contact with the first main surface Wa of the substrate W in the state in which the substrate W is held by the holding part  20 , and polishes the first main surface Wa. The polishing head  70  has, for example, a cylindrical shape, and a polishing surface of the polishing head  70  in contact with the substrate W is disposed horizontally. The polishing surface of the polishing head  70  is smaller than the first main surface Wa of the substrate W. 
     The polishing head  70  is connected to a rotary motor  72  via a vertical rotary shaft  71 . The rotary motor  72  rotates the polishing head  70  around the rotary shaft  71 . A transmission member that transmits a rotational motion of the rotary motor  72  to the rotary shaft  71  may be disposed between the rotary motor  72  and the rotary shaft  71 . The transmission member includes, for example, a belt, a pulley, and the like. 
     As shown in  FIG. 3 , the polishing head  70  includes a mounting part  701  that is exchangeably mounted on the rotary shaft  71 , and a polishing layer  702  that is pressed against the substrate W. The polishing layer  702  includes a base material made of resin, and polishing particles dispersedly arranged on the base material. The polishing particles are, for example, diamond particles, silicon carbide particles, or the like. The polishing layer  702  has a cylindrical shape, and the lower surface of the polishing layer  702  polishes the substrate W. 
     Drainage grooves  703  are formed on the lower surface of the polishing layer  702 . A plurality of drainage grooves  703  are formed at equal intervals on the lower surface of the polishing layer  702  in the circumferential direction, and intersect with each another at the center of the lower surface of the polishing layer  702 . The cleaning liquid that has entered between the polishing layer  702  and the substrate W is discharged from the center of the lower surface of the polishing layer  702  toward the peripheral edge along the drainage grooves  703 . 
     The structure of the polishing head  70  is not limited to the structure shown in  FIG. 3 . 
     As shown in  FIG. 1A  and the like, the moving part  80  includes, for example, a first moving part  81  and a second moving part  82 . The first moving part  81  moves the polishing head  70  in the Z-axis direction and presses the polishing head  70  against the first main surface Wa of the substrate W. Further, the second moving part  82  moves the polishing head  70  in the X-axis direction to scan the polishing head  70  in the radial direction of the substrate W. 
     The controller  90  is, for example, a computer, and includes a CPU (central processing part)  91  and a storage medium  92  such as a memory. The storage medium  92  stores a program that controls various processes executed by the substrate processing apparatus  10 . The controller  90  controls the operation of the substrate processing apparatus  10  by causing the CPU  91  to execute the program stored in the storage medium  92 . Further, the controller  90  includes an input interface  93  and an output interface  94 . The controller  90  receives external signals through the input interface  93 , and transmits signals to the outside through the output interface  94 . 
     The program is stored in, for example, a non-transitory computer-readable storage medium and is installed on the storage medium  92  of the controller  90  from the computer-readable storage medium. Examples of the computer-readable storage medium may include a hard disk (HD), a flexible disk (FD), a compact disc (CD), a magnet optical disc (MO), a memory card, and the like. The program may be downloaded from a server via the Internet and installed on the storage medium  92  of the controller  90 . 
     Next, the operation of the substrate processing apparatus  10 , that is, a substrate processing method, will be described with reference to  FIG. 4  and the like. As shown in  FIG. 4 , the substrate processing method includes a loading step S 1 , a polishing step S 2 , a cleaning step S 3 , a drying step S 4 , and an unloading step S 5 . This substrate processing method is performed under the control of the controller  90 . 
     In the loading step S 1 , a transfer device (not shown) loads the substrate W into the substrate processing apparatus  10  and delivers the same to the holding part  20 . The holding part  20  holds the substrate W horizontally with the first main surface Wa of the substrate W oriented upward. After delivering the substrate W to the holding part  20 , the transfer device is withdrawn outward from the substrate processing apparatus  10 . 
     In the polishing step S 2 , as shown in  FIG. 1A , the first main surface Wa of the substrate W is polished by the polishing head  70  while the substrate W is held by the holding part  20 . The first main surface Wa is mounted on the exposure machine while being polished by the polishing head  70  to remove deposits and scratches. Since adsorption distortion of the first main surface Wa is small when the first main surface Wa is mounted on the exposure machine, distortion of the second main surface Wb is also small so that defocus can be reduced, thereby improving the pattern processing accuracy. 
     In the polishing step S 2 , the moving part  80  scans the polishing head  70  in the radial direction of the substrate W in a state in which the polishing head  70  is pressed against the first main surface Wa of the substrate W. Further, in the polishing step S 2 , the rotating part  25  rotates the holding part  20  to rotate the substrate W together with the holding part  20 . Further, in the polishing step S 2 , the rotary motor  72  rotates the polishing head  70 . 
     The controller  90  controls the moving part  80  to control a polishing pressure of the polishing head  70  and a scanning speed of the polishing head  70 . Further, the controller  90  controls the rotating part  25  to control a rotation speed of the substrate W. Further, the controller  90  controls the rotary motor  72  to control a rotation speed of the polishing head  70 . 
     As shown in  FIG. 6 , the controller  90  sets two division lines L 1  and L 2  that divide the first main surface Wa of the substrate W into three areas A 1  to A 3  in the radial direction of the substrate W. The two division lines L 1  and L 2  are circles centered on a center point P 0  of the first main surface Wa, and divide the first main surface Wa into the three areas A 1  to A 3  at equal intervals in the radial direction. The number of division lines is not limited to two, and may be one or more. Further, the number of areas may be two or more. Further, the division lines may divide the first main surface Wa at unequal intervals rather than at equal intervals, in the radial direction. 
     The central area A 1  includes the center point P 0  of the first main surface Wa of the substrate W and has a radius larger than the diameter of the lower surface of the polishing head  70 . The lower surface of the polishing head  70  passes through the center point P 0  of the first main surface Wa, a point P 1  of the division line L 1 , and a point P 2  of the division line L 2  in this order in a state in which the lower surface of the polishing head  70  is pressed against the first main surface Wa of the substrate W, and moves to a point P 3  on the peripheral edge of the first main surface Wa. 
     As shown in  FIG. 5 , the controller  90  performs the supply of the cleaning liquid and the scanning of the polishing head  70  in a state in which the subsequent supply of the cleaning liquid is stopped, for each of the areas A 1  to A 3 . The supply of the cleaning liquid and the scanning of the polishing head are managed at the position of a front end F of the polishing head  70 . The front end F is a front end in the scanning direction. The details of  FIG. 5  are as follows. 
     First, the first nozzle  31  supplies the cleaning liquid to the center of the first main surface Wa of the substrate W while the substrate W is rotating (S 201  in  FIG. 5 ). The cleaning liquid soaks and spreads over the entire first main surface Wa by virtue of a centrifugal force to form a liquid film. During that time, the second nozzle  41  does not supply the cleaning liquid to the substrate W. The polishing head  70  is separated upward from the substrate W and stands by above the substrate W. 
     After the liquid film is formed, the first nozzle  31  stops the supply of the cleaning liquid (S 202  in  FIG. 5 ). Further, after the liquid film is formed, the moving part  80  lowers the polishing head  70  and presses the polishing head  70  against the first main surface Wa of the substrate W. During the formation of the liquid film or before the formation of the liquid film, as shown in  FIG. 6 , the position of the polishing head  70  is adjusted so that the front end F of the polishing head  70  coincides with the center point P 0  of the first main surface Wa when viewed from the top. 
     Subsequently, in the state in which the polishing head  70  is pressed against the first main surface Wa of the substrate W, the moving part  80  scans the front end F of the polishing head  70  from the center point P 0  of the first main surface Wa to the point P 1  of the division line L 1  (S 203  in  FIG. 5 ). During that time, the controller  90  stops supplying the cleaning liquid to the substrate W, and performs the rotation of the substrate W and the polishing head  70 . 
     When the front end F of the polishing head  70  reaches the point P 1  of the division line L 1 , the controller  90  suspends the scanning of the polishing head  70  and temporarily stops the front end F of the polishing head  70  at the point P 1  of the division line L 1 . Then, the controller  90  performs the supply of the cleaning liquid (S 204  in  FIG. 5 ). 
     Specifically, the first nozzle  31  supplies the cleaning liquid to the center of the first main surface Wa of the substrate W while the substrate W is rotating. The cleaning liquid soaks and spreads over the entire first main surface Wa by virtue of a centrifugal force to form the liquid film. During the formation of the liquid film, the moving part  80  keeps pressing the polishing head  70  against the substrate W. During the formation of the liquid film, since the cleaning liquid continues to be supplied, the cleaning liquid flows continuously between the polishing head  70  and the substrate W and the polishing head  70  slips with respect to the substrate W, so that the substrate W is substantially not polished. During the formation of the liquid film, the moving part  80  may separate the polishing head  70  from the substrate W and stand by above the substrate W instead of continuing to press the polishing head  70  against the substrate W. In that case, the moving part  80  lowers the polishing head  70  and presses the polishing head  70  against the substrate W again before resuming the scanning. 
     After the formation of the liquid film, the first nozzle  31  stops the supply of the cleaning liquid (S 205  in  FIG. 5 ). 
     Subsequently, in the state in which the polishing head  70  is pressed against the first main surface Wa of the substrate W, the moving part  80  scans the front end F of the polishing head  70  from the point P 1  of the division line L 1  to the point P 2  of the other division line L 2  (S 206  in  FIG. 5 ). During that time, the controller  90  stops the supply of the cleaning liquid to the substrate W and performs the rotation of the substrate W and the polishing head  70 . 
     When the front end F of the polishing head  70  reaches the point P 2  of the division line L 2 , the controller  90  suspends the scanning of the polishing head  70  and temporarily stops the front end F of the polishing head  70  at the point P 2  of the division line L 2 . Then, the controller  90  performs the supply of the cleaning liquid (S 207  in  FIG. 5 ). The step S 207  is performed in the same manner as in the step S 204 . After that, the first nozzle  31  stops the supply of the cleaning liquid (S 208  in  FIG. 5 ). 
     Subsequently, in the state in which the polishing head  70  is pressed against the first main surface Wa of the substrate W, the moving part  80  scans the front end F of the polishing head  70  from the point P 2  of the division line L 2  to the point P 3  of the peripheral edge of the first main surface Wa (S 209  in  FIG. 5 ). During that time, the controller  90  stops the supply of the cleaning liquid to the substrate W and performs the rotation of the substrate W and the polishing head  70 . 
     When the front end F of the polishing head  70  reaches the point P 3  on the peripheral edge of the first main surface Wa of the substrate W, the controller  90  terminates the scanning of the polishing head  70  and stops the front end F of the polishing head  70  at the point P 2  of the division line L 2 . In that state, the controller  90  performs the rotation of the substrate W and the polishing head  70  for a set time to polish the peripheral edge of the substrate W (S 210  in  FIG. 5 ). This is because dirt easily adheres to the peripheral edge of the substrate W. According to this embodiment, dirt adhering to the peripheral edge of the substrate W can be removed. After that, the polishing head  70  is separated from the first main surface Wa of the substrate W. 
     As described above, as shown in  FIG. 5 , the controller  90  performs the supply of the cleaning liquid and the scanning of the polishing head  70  in the state in which the subsequent supply of the cleaning liquid is stopped, for each of the areas A 1  to A 3 . The controller  90  temporarily suspends the scan during the scanning of the polishing head  70  and supplies the cleaning liquid. It is possible to prevent the liquid film of the cleaning liquid from being cut off during the scanning and thus it is possible to prevent the occurrence of excessive friction. Further, since the controller  90  prohibits the supply of the cleaning liquid during the scanning, a liquid film having an appropriate thickness can be formed between the polishing head  70  and the substrate W. Therefore, while suppressing the occurrence of scratches due to friction, slip can be suppressed and the substrate W can be polished. Moreover, since the liquid film remains, polishing debris can be washed away together with the cleaning liquid by virtue of a centrifugal force. As a result, the substrate W can be polished entirely in the radial direction while suppressing the occurrence of scratches on the substrate W. 
     Although the controller  90  performs the process shown in  FIG. 5  once in the present embodiment, the process may be performed a plurality of times. That is, the number of times of scanning of the polishing head  70  is one in this embodiment, but may be a plurality of times. 
     By the way, as shown in  FIG. 7 , when the rotation speed of the substrate W is constant, the friction coefficient between the polishing head  70  and the substrate W decreases as the distance from the center point P 0  of the first main surface Wa of the substrate W increases. A curve shown in  FIG. 7  is generally called a Strivec Curve. 
     As the friction coefficient between the polishing head  70  and the substrate W increases, the substrate W is likely to be cut. Therefore, as shown in  FIG. 8 , the controller  90  sets one or more of the polishing pressure of the polishing head  70 , the scanning speed of the polishing head  70 , and the rotation speed of the substrate W for each of the areas A 1  to A 3  in order to cut the plurality of areas A 1  to A 3  to the same extent. 
     The larger the polishing pressure of the polishing head  70 , the larger the frictional force between the polishing head  70  and the substrate W. Thus, the substrate W can easily be cut. The frictional force is expressed as the product of the polishing pressure and the friction coefficient. Further, when the rotation speed of the substrate W is constant, as the scanning speed of the polishing head  70  decreases, the number in which a specific point on the rotating substrate W crosses over the polishing head  70  during the scanning is increased. Thus, the substrate W is easily to be cut at the specific point. Further, when the scanning speed of the polishing head  70  is constant, as the rotation speed of the substrate W increases, the number in which a specific point on the rotating substrate W crosses over the polishing head  70  during the scan is increased. Thus, the substrate W can easily be cut at the specific point. 
     As described above, the controller  90  sets one or more of the polishing pressure of the polishing head  70 , the scanning speed of the polishing head  70 , and the rotation speed of the substrate W for each of the areas A 1  to A 3 . Since the plurality of areas A 1  to A 3  can be cut to the same extent, the surface roughness of the areas A 1  to A 3  after polishing can be kept within the same allowable range. 
     The controller  90  sets one or more of the polishing pressure of the polishing head  70 , the scanning speed of the polishing head  70 , and the rotation speed of the substrate W according to the conditions of the first main surface Wa of the substrate W. Data indicating the relationship between the conditions of the first main surface Wa of the substrate W and the set values is created in advance by experiment or the like and stored in the storage medium  92 . The controller  90  acquires the conditions of the first main surface Wa of the substrate W from an external computer via the input interface  93 , and refers to the above data stored in the storage medium  92  to determine the set values. In addition, the conditions of the first main surface Wa of the substrate W can be acquired by a surface inspection means such as a camera or a laser provided in the substrate processing apparatus  10 . The controller  90  may determine the conditions of the first main surface Wa of the substrate W from the inspection result of the surface inspection means to determine the set values. 
     The conditions of the first main surface Wa of the substrate W includes a material of the film W 2  formed on the first main surface Wa. In a case in which the material of the film W 2  is an amorphous silicon, the hardness of the film W 2  becomes softer and the film W 2  can more easily be cut compared with a case in which the material of the film W 2  is silicon oxide or silicon nitride. 
     Therefore, as the hardness of the film W 2  becomes softer, the polishing pressure of the polishing head  70  is set to be smaller. Further, as the hardness of the film W 2  becomes softer, the scanning speed of the polishing head  70  is set to be higher. Alternatively, as the hardness of the film W 2  becomes softer, the rotation speed of the substrate W is set to be lower. 
     The conditions of the first main surface Wa of the substrate W may include the thickness of the film W 2  in addition to the material of the film W 2 . The thicker the film W 2 , the more easily the difference in the material of the film W 2  is expressed by the difference in the hardness of the film W 2 . 
     The conditions of the first main surface Wa of the substrate W includes a radial distribution of the surface roughness of the first main surface Wa after polishing. The surface roughness is expressed by, for example, a Haze value. The larger the Haze value, the larger the surface roughness. The reflectance of light or the like may be used instead of the Haze value. The smaller the reflectance, the larger the surface roughness. 
     If the surface roughness is too small, it means that the amount of polishing is too small. On the other hand, if the surface roughness is too large, it means that the amount of polishing is too large. Therefore, the polishing pressure of the polishing head  70  and the like are set so that the surface roughness is kept within the allowable range. 
     For example, as the surface roughness becomes larger, the polishing pressure of the polishing head  70  is set to be smaller. Further, as the surface roughness becomes larger, the scanning speed of the polishing head  70  is set to be higher. Alternatively, as the surface roughness becomes larger, the rotation speed of the substrate W is set to be smaller. 
     The order of setting change may be the order of the polishing pressure of the polishing head  70 , the scanning speed of the polishing head  70 , and the rotation speed of the substrate W, or vice versa. A degree of influence of the setting change on the ease of cutting of the substrate W is greater in the order of the polishing pressure of the polishing head  70 , the scanning speed of the polishing head  70 , and the rotation speed of the substrate W. 
     Therefore, when it is desired to greatly change the polishing amount of the substrate W, the priority of the setting change is the order of the polishing pressure of the polishing head  70 , the scanning speed of the polishing head  70 , and the rotation speed of the substrate W. On the other hand, when it is desired to change the polishing amount of the substrate W to be small, the priority of the setting change is the order of the rotation speed of the substrate W, the polishing pressure of the polishing head  70 , and the scanning speed of the polishing head  70 . 
     In the cleaning step S 3  of  FIG. 4 , first, the first nozzle  31  supplies the cleaning liquid to the center of the first main surface Wa of the substrate W. The cleaning liquid soaks and spreads over the entire first main surface Wa by virtue of a centrifugal force, and dirt separated from the substrate W is drifted radially outward of the substrate W. A rinsing liquid such as DIW is used as the cleaning liquid. In addition, a chemical liquid and a rinsing liquid may be used as the cleaning liquid in order. 
     In the cleaning step S 3  of  FIG. 4 , subsequently, the second nozzle  41  gradually moves from a position immediately above the center of the substrate W to a position immediately above the peripheral edge of the substrate W while discharging the cleaning liquid toward the first main surface Wa of the substrate W, and stops at the position immediately above the peripheral edge of the substrate W for a set time. This is because dirt easily adheres to the peripheral edge of the substrate W. 
     Further, the movement direction of the second nozzle  41  is the radial outward direction of the substrate W in the present embodiment, but may be a radial inward direction of the substrate W. Further, the number of times of the scanning of the second nozzle  41  is one in the present embodiment, but may be plural. 
     In the cleaning step S 3  of  FIG. 4 , the first nozzle  31  further supplies the cleaning liquid to the center of the first main surface Wa of the substrate W. The cleaning liquid soaks and spreads over the entire first main surface Wa by virtue of a centrifugal force, and dirt separated from the substrate W is drifted radially outward of the substrate W. A rinsing liquid such as DIW may be used as the cleaning liquid. 
     In the drying step S 4  of  FIG. 4 , the rotating part  25  rotates the holding part  20  at a high speed to drop the cleaning liquid adhering to the substrate W from the substrate W. At the end of the cleaning step S 3 , the liquid film of the rinsing liquid may be replaced with a liquid film of a dry liquid having a surface tension smaller than that of the rinsing liquid. In that case, the dry liquid is dropped in the drying step S 4 . For example, IPA (isopropyl alcohol) or the like may be used as the dry liquid. 
     In the unloading step S 5  of  FIG. 5 , a transfer device (not shown) enters the inside of the substrate processing apparatus  10 , receives the substrate W from the holding part  20 , and unloads the substrate W from the substrate processing apparatus  10 . After that, this process ends. 
     Next, experimental data will be described with reference to Table 1 and  FIG. 9 . Table 1 shows the polishing conditions in Examples 1 and 2 and Reference Example 1. 
     
       
         
           
               
               
               
               
             
               
                 TABLE 1 
               
             
            
               
                   
               
               
                   
                 Area A1 
                 Area A2 
                 Area A3 
               
            
           
           
               
               
               
               
               
               
               
               
               
               
               
               
               
            
               
                   
                 V 
                 N1 
                   
                 N2 
                 V 
                 N1 
                   
                 N2 
                 V 
                 N1 
                   
                 N2 
               
               
                   
                 [mm/s] 
                 [rpm] 
                 T [s] 
                 [Times] 
                 [mm/s] 
                 [rpm] 
                 T [s] 
                 [Times] 
                 [mm/s] 
                 [rpm] 
                 T [s] 
                 [Times] 
               
               
                   
               
            
           
           
               
               
               
               
               
               
               
               
               
               
               
               
               
            
               
                 Example 1 
                 9 
                 1000 
                 8.9 
                 148 
                 5 
                 1000 
                 10 
                 167 
                 7 
                 1000 
                 8.9 
                 148 
               
               
                 Example 2 
                 9 
                 750 
                 8.9 
                 111 
                 5 
                 1000 
                 10 
                 167 
                 7 
                 1000 
                 8.9 
                 148 
               
               
                 Reference 
                 15 
                 1000 
                 10.7 
                 178 
                 1 
                 1000 
                 10 
                 167 
                 7 
                 1000 
                 17.7 
                 295 
               
               
                   
               
            
           
         
       
     
     In Table 1, V represents the scanning speed of the polishing head  70 , N 1  represents the rotation speed of the substrate W, T represents the polishing time of the substrate W in each area A 1  to A 3 , and N 2  represents the number of rotations (N 2 =N 1 ×T/60) of the substrate W during time T. Here, “60” is a coefficient for correcting the unit of time T from “second” to “minute”. T in the area A 1  is the time in step S 203  in  FIG. 5 , T in the area A 2  is the time in step S 206  in  FIG. 5 , and T in the area A 3  is the total time in steps S 209  and S 210  in  FIG. 5 . 
     In both Examples 1 and 2 and Reference Example, the substrate W includes a silicon wafer, a silicon oxide film, and a polycrystalline silicon film in this order. The radius of the substrate W was 150 mm. The two division lines L 1  and L 2  divided the substrate W into three areas at equal intervals in the radial direction. The polishing pressure was constant at a level of 1.5N. 
     In Reference Example, as in Patent Document 1, V was gradually reduced while scanning the polishing head  70  radially outward from radially inward of the substrate W. Further, in Reference Example, as in Patent Document 1, the cleaning liquid was continuously supplied during the scanning of the polishing head  70 . The Haze value after polishing was small in the areas A 1  and A 2  excluding the area A 3  in the radial outward direction of the substrate W, as indicated by a broken line in  FIG. 9 . Therefore, it can be found that the amount of polishing was not sufficient in the areas A 1  and A 2  excluding the area A 3  in the outside of the substrate W in the radial direction. 
     Therefore, in Example 1, unlike Reference Example, the supply of the cleaning liquid was stopped during the scanning of the polishing head  70 , as shown in  FIG. 5 . Further, in Example, V was set to be the smallest in the middle of scanning the polishing head  70  radially outward from radially inward of the substrate W. The Haze value after polishing was large in all the areas A 1 , A 2 , and A 3 , as indicated by a solid line in  FIG. 9 . Therefore, it can be found that the amount of polishing was sufficient in all the areas A 1 , A 2 , and A 3 . 
     By the way, in Example 1, the Haze value in the area A 1  in the radial inward direction of the substrate W was larger than the Haze values in the other areas A 2  and A 3 . Therefore, in Example 1, it can be found that the polishing amount in the radial inward direction of the substrate W was larger than the polishing amount in the other areas A 2  and A 3 . 
     Therefore, in Example 2, in order to reduce the amount of polishing in the area A 1  in the radial inward direction of the substrate W, the substrate W was polished under the same conditions as in Example 1 except that N 1  in the area A 1  is reduced. The Haze value after polishing was about the same in all the areas A 1 , A 2 , and A 3 , as indicated by a dash-dot line in  FIG. 9 . Therefore, in Example 2, it can be found that the polishing amount was about the same in all the areas A 1 , A 2 , and A 3 . 
     According to the present disclosure in some embodiments, it is possible to polish the entire substrate in a radial direction of the substrate while suppressing the occurrence of scratches on the substrate. 
     Although the embodiment of the substrate processing apparatus and the substrate processing method according to the present disclosure has been described above, the present disclosure is not limited to the above embodiment and the like. Various changes, modifications, replacements, additions, deletions, and combinations are possible within the category of the claims. It is natural that these also belong to the technical scope of the present disclosure.