Patent Publication Number: US-11642704-B2

Title: Roll-type processing member, pencil-type processing member, and substrate processing apparatus including any one of these

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of U.S. Non-Provisional patent application Ser. No. 14/920,045, filed on Oct. 22, 2015 and Japanese Patent Application No. 2014-223754, filed on Oct. 31, 2014, the content of which is incorporated herein by reference. 
     FIELD 
     The technology relates to a roll-type processing member (particularly, a roll-type processing member having nodules formed on a surface thereof) that scrubs a surface of a substrate such as a semiconductor wafer while rotating about an axis parallel to the surface of the substrate so as to process the surface of the substrate, a pencil-type processing member that processes the surface of the substrate while contacting the substrate, and a substrate processing apparatus that uses any one of the roll-type processing member and the pencil-type processing member. 
     BACKGROUND 
     In recent years, a substrate (a substrate having films of various materials with different properties) having a microscopic structure is processed in accordance with a decrease in size of a semiconductor device. For example, in a damascene wiring process of burying a wiring groove formed in a substrate by metal, extra metal is removed by polishing using a substrate polishing apparatus (a CMP apparatus) after a damascene wiring is formed, and films (a metal film, a barrier film, an insulation film, and the like) of various materials having different properties are formed on the surface of the substrate. Slurry residues or metal polishing chips (Cu polishing chips) which are used in CMP polishing exist on the surface of the substrate. For that reason, when the surface of the substrate is complex and is not sufficiently cleaned due to the difficulty in cleaning the surface of the substrate, a leakage or a poor adhesion occurs due to the influence of residues. Accordingly, there is a concern that the reliability may be degraded. Here, a cleaning treatment is performed after the polishing treatment in the CMP apparatus that polishes the semiconductor substrate. 
     As the substrate cleaning method, a roll cleaning treatment (for example, see WO 98/020987 A) is known in which a member (a roll-type cleaning member) such as a cylindrical sponge is held so that the axis is parallel to the surface of the substrate and is rotated about the axis while scrubbing the surface of the substrate at the side surface thereof so as to scrub-clean the surface of the substrate or a pencil cleaning treatment (for example, see JP 8-141521 A) is known in which a member (a pencil-type cleaning member) such as a cylindrical sponge is held so that the axis is perpendicular to the surface of the substrate and is brought into contact with the surface of the rotating substrate at the bottom surface thereof so as to scrub-clean the surface of the substrate. 
     A plurality of small columnar protrusions (nodules) is formed on the surface of the roll-type cleaning member and the roll-type cleaning member rotates about the axis parallel to the surface of the substrate, the nodules sequentially scrub the surface of the substrate so as to clean the surface of the substrate. Although a cleaning liquid is supplied onto the substrate during the scrub-cleaning treatment, JP H8-141521 A has a structure in which a slit is formed on the bottom surface of the pencil-type cleaning member in order to uniformly supply the cleaning liquid to a cleaning portion. 
     SUMMARY 
       FIG.  23    is a diagram illustrating a state where a nodule of a roll-type cleaning member scrubs a surface of a substrate. Further,  FIG.  24 A  is a perspective view illustrating each nodule,  FIG.  24 B  is a diagram illustrating a cleaning surface (a surface contacting the substrate) of the nodule not contacting the substrate, and  FIG.  24 C  is a diagram illustrating the cleaning surface of the nodule contacting the substrate. In  FIGS.  24 A to  24 C , the arrow a indicates the longitudinal direction (the rotation axis direction) of the roll-type cleaning member, and the arrow c indicates the rotation direction (the circumferential direction) of the surface of the roll-type cleaning member. 
     As illustrated in  FIGS.  24 A and  24 B , each nodule N has a columnar shape, and a cleaning surface CF has a circular shape. However, when the nodule N contacts the front surface (the target cleaning surface) of the substrate S by the rotation of a roll-type cleaning member R as illustrated in  FIG.  23   , the nodule N is pressed, and dragged and deformed by the surface of the substrate S. As a result, the cleaning surface CF is also crushed in the rotation direction as illustrated in  FIG.  24 C . However, the pressure applied to the cleaning surface CF of the nodule N is intensively applied to the vicinity of the upstream edge (the hatching portion of  FIG.  24 C ) as illustrated in  FIG.  24 C , and hence the contribution degree for the cleaning of the other portion decreases. 
     Further, in JP H8-141521 A in which the slit is formed on the bottom surface of the pencil-type cleaning member, the cleaning liquid entering the slit stays in the slit when the cleaning liquid is supplied from the outside of the pencil-type cleaning member to the surface of the substrate. As a result, a problem arises in that a fresh cleaning liquid cannot be supplied to the cleaning portion. 
     Although the cleaning apparatus has been described above, a buff processing apparatus also scrubs the surface of the substrate by using a roll-type buff processing member having the nodule or a pencil-type buff processing member having the slit. In this case, the above-described problem may arise. 
     An object of the technology is to improve the processing ability of the substrate processing treatment (the cleaning treatment or the buff processing treatment) of scrubbing the surface of the substrate by using a roll-type processing member having the nodule or a pencil-type processing member having the slit. 
     A roll-type processing member according to an aspect of the present disclosure is a roll-type processing member for processing a surface of a substrate by scrubbing the surface of the substrate, including: a nodule which is formed on a surface of the roll-type processing member, wherein the nodule includes a plurality of upstream edges which are provided in the rotation direction of the roll-type processing member, the plurality of upstream edges being edges located at the upstream sides of a front end surface of the nodule when the front end surface contacts the surface of the substrate by the rotation of the roll-type processing member. 
     With this configuration, since the upstream edges of each nodule scrub the target cleaning surface plural times, the cleaning effect of each nodule is improved. 
     At least one of the plurality of upstream edges may be formed in a manner such that a slit or a concave portion is formed on the front end surface of the nodule. 
     The adjacent nodules in the rotation direction of the roll-type processing member may include an overlap portion in which the adjacent nodules overlap each other in the rotation axis direction of the roll-type processing member, and the at least one of the plurality of upstream edges formed by the slit or the concave portion may have a length in which a non-overlap portion except for the overlap portion in the front end surface is covered in the rotation axis direction of the roll-type processing member. 
     With this configuration, since two nodule rows scrub the target cleaning surface of the substrate, the upstream edges scrub the target cleaning surface of the substrate twice even at the non-overlap portion, and hence the cleaning effect in the non-overlap portion is improved. 
     The slit or the concave portion may have a shape which is narrowed in the depth direction. 
     With this configuration, since the nodule is pressed and dragged by the target cleaning surface of the substrate, the slit or the concave portion is buried, and hence the possibility of removing the upstream edges can be decreased. 
     A roll-type processing member according to another aspect of the technology is a roll-type processing member for processing a surface of a substrate by scrubbing the surface of the substrate, including: a nodule which is formed on a surface of the roll-type processing member, wherein the nodule includes a slit or a concave portion which extends so as not to be parallel to the rotation direction of the roll-type processing member. 
     With this configuration, since the plurality of upstream edges exists in each nodule so that the upstream edges scrub the target cleaning surface, the cleaning effect of each nodule is improved. 
     The slit may be bent in a convex shape in the rotation direction of the roll-type processing member. 
     With this configuration, dirt inside the slit is scraped out to the left and right sides by the rotation of the roll-type processing member (the movement of the nodule). 
     A substrate cleaning apparatus according to another aspect of the technology includes: any one of the above-described roll-type processing members; a rotational driving mechanism which rotates the roll-type processing member about the rotation axis; and a substrate holder which holds the substrate so that the surface of the substrate is parallel to the rotation axis direction of the roll-type processing member at a position contacting the nodule of the roll-type processing member. 
     Even with this configuration, since the upstream edges of each nodule scrub the target cleaning surface plural times, the cleaning effect of each nodule is improved. 
     A pencil-type processing member according to an aspect of the technology is a pencil-type processing member for processing a surface of a substrate by scrubbing the surface of the substrate at a bottom surface thereof, wherein a continuous slit is formed on the bottom surface while not being divided from one edge to the other edge. 
     With this configuration, since the slit is formed in the bottom surface of the pencil-type processing member that scrubs the surface of the substrate, any one of both sides of the slit becomes the upstream edge, and hence the processing ability of scrubbing the surface of the substrate is improved compared with the pencil-type processing member without any slit. Further, since the slit is continuously formed while not being divided from one edge to the other edge, the liquid supplied to the surface of the substrate is easily led to and discharged from the slit, and hence a fresh liquid can be supplied to the slit. 
     The slit may be formed in a linear shape. 
     With this configuration, the liquid supplied to the surface of the substrate can be easily led to and discharged from the slit. 
     The pencil-type processing member may include a plurality of slits having different depths. 
     Since the depths of the plurality of slits are adjusted, the partial deformation among the slits of the pencil-type processing member can be adjusted. For example, the slit close to the center can be set to a comparatively deep depth and the slit separated from the center can be set to a comparatively shallow depth. Alternatively, the slit can be formed in a reverse manner. 
     The pencil-type processing member is a pencil-type cleaning member for performing a cleaning treatment on the surface of the substrate, and the pencil-type cleaning member may be formed of a soft sponge. 
     With this configuration, the scrub-cleaning treatment can be performed while the surface of the substrate is scrubbed by the pencil-type cleaning member. 
     The pencil-type processing member may be a pencil-type buff processing member for performing a buff processing treatment on the surface of the substrate, and the pencil-type buff processing member may includes a base portion and a buff processing pad which is provided at the lower surface of the base portion so as to become a bottom surface. 
     With this configuration, the buff processing treatment can be performed while the surface of the substrate is scrubbed by the pencil-type buff processing member. 
     A substrate processing apparatus according to another aspect of the technology includes: any one of the above-described pencil-type processing members; a rotational driving mechanism which rotates the pencil-type processing member about the rotation axis perpendicular to the bottom surface; and a substrate holder which holds the substrate so that the surface of the substrate is parallel to the bottom surface of the pencil-type processing member at a position contacting the bottom surface of the pencil-type processing member. 
     Even with this configuration, since the slit is formed in the bottom surface of the pencil-type processing member that scrubs the surface of the substrate, any one of both sides of the slit becomes the upstream edge, and hence the processing ability of scrubbing the surface of the substrate is improved compared with the pencil-type processing member without any slit. Further, since the slit is continuously formed while not being divided from one edge to the other edge, the liquid supplied to the surface of the substrate is easily led to and discharged from the slit, and hence a fresh liquid can be supplied to the slit. 
     A substrate processing apparatus according to another aspect of the technology includes: any one of the above-described pencil-type processing members; and a substrate rotation mechanism which holds and rotates the substrate so that the surface of the substrate is parallel to the bottom surface of the pencil-type processing member at a position contacting the bottom surface of the pencil-type processing member. 
     Even with this configuration, since the slit is formed in the bottom surface of the pencil-type processing member that scrubs the surface of the substrate, any one of both sides of the slit becomes the upstream edge, and hence the processing ability of scrubbing the surface of the substrate is improved compared with the pencil-type processing member without any slit. Further, since the slit is continuously formed while not being divided from one edge to the other edge, the liquid supplied to the surface of the substrate is easily led to and discharged from the slit, and hence a fresh liquid can be supplied to the slit. 
     According to any one of several aspects of the technology, since the upstream edges of each nodule scrub the surface of the substrate plural times, the processing ability of scrubbing the surface of the substrate by each nodule is improved. Further, according to another aspect of the technology, since the bottom surface of the pencil-type processing member that scrubs the surface of the substrate is provided with the slit which is continuous while not being divided from one edge to the other edge, the processing ability of scrubbing the surface of the substrate is improved. At this time, since the liquid supplied to the surface of the substrate is easily led to and discharged from the slit, a fresh liquid can be supplied to the slit. 
     As will be described below, the technology may be implemented in various forms. Thus, the disclosure of the technology is only a part of the technology, and is not intended to limit the scope of claims of the technology. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG.  1    is a perspective view illustrating an outline of a cleaning apparatus of a first embodiment of the technology. 
         FIG.  2    is a perspective view illustrating a roll-type cleaning member of the first embodiment of the technology. 
         FIG.  3    is a front view illustrating the roll-type cleaning member of the first embodiment of the technology. 
         FIG.  4    is a cross-sectional view taken along the line A-A of  FIG.  3   . 
         FIG.  5 A  is a perspective view of a nodule of the first embodiment of the technology. 
         FIG.  5 B  is a diagram illustrating a state where a cleaning surface of the nodule of the first embodiment of the technology does not contact a substrate. 
         FIG.  5 C  is a diagram illustrating a state where the cleaning surface of the nodule of the first embodiment of the technology contacts the substrate. 
         FIG.  6    is a diagram illustrating a state where the nodule of the first embodiment of the technology scrubs the surface of the substrate. 
         FIG.  7    is a partially enlarged view of  FIG.  6   . 
         FIG.  8 A  is a diagram illustrating another example of a cleaning surface of a nodule provided with two upstream edges in the rotation direction of the first embodiment of the technology. 
         FIG.  8 B  is a diagram illustrating another example of a cleaning surface of a nodule provided with two upstream edges in the rotation direction of the first embodiment of the technology. 
         FIG.  8 C  is a diagram illustrating another example of a cleaning surface of a nodule provided with two upstream edges in the rotation direction of the first embodiment of the technology. 
         FIG.  8 D  is a diagram illustrating another example of a cleaning surface of a nodule provided with two upstream edges in the rotation direction of the first embodiment of the technology. 
         FIG.  8 E  is a diagram illustrating another example of a cleaning surface of a nodule provided with two upstream edges in the rotation direction of the first embodiment of the technology. 
         FIG.  8 F  is a diagram illustrating another example of a cleaning surface of a nodule provided with two upstream edges in the rotation direction of the first embodiment of the technology. 
         FIG.  9    is a diagram illustrating a relation in arrangement between a second upstream edge and a plurality of nodules of the first embodiment of the technology. 
         FIG.  10 A  is a diagram illustrating a modified example of a nodule of the first embodiment of the technology. 
         FIG.  10 B  is a diagram illustrating a modified example of a nodule of the first embodiment of the technology. 
         FIG.  11 A  is a diagram illustrating a modified example of a nodule of the first embodiment of the technology. 
         FIG.  11 B  is a diagram illustrating a modified example of a nodule of the first embodiment of the technology. 
         FIG.  12 A  is a diagram illustrating a modified example of a nodule of the first embodiment of the technology. 
         FIG.  12 B  is a diagram illustrating a modified example of a nodule of the first embodiment of the technology. 
         FIG.  13 A  is a diagram illustrating a modified example of a nodule of the first embodiment of the technology. 
         FIG.  13 B  is a diagram illustrating a modified example of a nodule of the first embodiment of the technology. 
         FIG.  14    is a diagram illustrating a modified example of a relation in direction between a slit formed in the nodule and a roll-type cleaning member of the first embodiment of the technology. 
         FIG.  15    is a perspective view illustrating an outline of a substrate cleaning apparatus of a second embodiment of the technology. 
         FIG.  16    is a perspective view of a pencil-type cleaning member of the second embodiment of the technology. 
         FIG.  17 A  is a bottom view of the pencil-type cleaning member of the second embodiment of the technology. 
         FIG.  17 B  is a front view of the pencil-type cleaning member of the second embodiment of the technology. 
         FIG.  18    is a top view illustrating a relation between the pencil-type cleaning member and the substrate of the second embodiment of the technology. 
         FIG.  19 A  is an enlarged view of a cleaning portion of the second embodiment of the technology (0°). 
         FIG.  19 B  is an enlarged view of the cleaning portion of the second embodiment of the technology (45°). 
         FIG.  19 C  is an enlarged view of the cleaning portion of the second embodiment of the technology (90°). 
         FIG.  19 D  is an enlarged view of the cleaning portion of the second embodiment of the technology (135°). 
         FIG.  20 A  is an enlarged view of the cleaning portion of the second embodiment of the technology (180°). 
         FIG.  20 B  is an enlarged view of the cleaning portion of the second embodiment of the technology (225°). 
         FIG.  20 C  is an enlarged view of the cleaning portion of the second embodiment of the technology (270°). 
         FIG.  20 D  is an enlarged view of the cleaning portion of the second embodiment of the technology (315°). 
         FIG.  21    is a perspective view illustrating an outline of a buff processing apparatus of a third embodiment of the technology. 
         FIG.  22    is a longitudinal sectional view of a pencil type buff processing member of the third embodiment of the technology. 
         FIG.  23    is a diagram illustrating a state where a nodule of a roll-type cleaning member scrubs a surface of a substrate. 
         FIG.  24 A  is a perspective view illustrating one nodule. 
         FIG.  24 B  is a diagram illustrating a cleaning surface of the nodule which does not contact the substrate. 
         FIG.  24 C  is a diagram illustrating the cleaning surface of the nodule which contacts the substrate. 
     
    
    
     DETAILED DESCRIPTION 
     A roll-type processing member, a pencil-type processing member, and a substrate processing apparatus including any one of these of an embodiment will hereinafter be given with reference to the drawings. In addition, the embodiment to be described below is an example of a case of the implementation of the technology, and the technology is not limited to the detailed configuration described below. In the implementation of the technology, a detailed configuration may be appropriately employed in response to the embodiment. 
     1. First Embodiment: Substrate Cleaning Apparatus Including Roll-Type Cleaning Member 
       FIG.  1    is a perspective view illustrating an outline of a substrate processing apparatus (a substrate cleaning apparatus) according to a first embodiment. As illustrated in  FIG.  1   , a substrate cleaning apparatus  10  includes a plurality of (in  FIG.  1   , four) spindles  11  (substrate holders) which serves as substrate rotation mechanisms movable in the horizontal direction, supports a circumferential edge of a substrate S so that a front surface of the substrate is directed upward, and rotates the substrate S in the horizontal direction, an upper roll-type cleaning member (roll sponge)  12  which is rotatably supported by a roll holder (not illustrated), and a lower roll-type cleaning member (roll sponge)  13  which is rotatably supported by a roll holder (not illustrated). Each of the upper roll-type cleaning member  12  and the lower roll-type cleaning member  13  is formed in a columnar shape, extends in an elongated shape, and is formed of, for example, PVA. In addition, the upper roll-type cleaning member  12  is elevatable up and down with respect to the front surface of the substrate S by the roll holder, and the lower roll-type cleaning member  13  is elevatable up and down with respect to the rear surface of the substrate S by the roll holder. 
     The upper roll-type cleaning member  12  rotates as indicated by the arrow F 1  by a driving mechanism (a rotational driving mechanism) not illustrated in the drawings, and the lower roll-type cleaning member  13  rotates as indicated by the arrow F 2  by a driving mechanism not illustrated in the drawings. Two cleaning liquid supply nozzles  14  and  15  are located above the substrate S supported and rotated by the spindles  11  so as to supply a cleaning liquid to the front surface of the substrate S. The cleaning liquid supply nozzle  14  is a nozzle which supplies a rinse liquid (for example, superpure water) to the front surface of the substrate S, and the cleaning liquid supply nozzle  15  is a nozzle which supplies a chemical liquid to the front surface of the substrate S. 
     The substrate cleaning apparatus  10  rotates the substrate S in the horizontal direction by rotating (spinning) a frame  11   a  while positioning the circumferential edge of the substrate S to a fitting groove formed on the outer circumferential surface of the frame  11   a  provided in the upper portion of the spindle  11  and pressing the circumferential edge inward. In this example, two frames  11   a  of four frames  11   a  apply a rotational force to the substrate S and the other two frames  11   a  serve as bearings to receive the rotation of the substrate S. In addition, all frames  11   a  may be connected to the driving mechanism so that a rotational force is applied to the substrate S. 
     In this way, the rinse liquid is supplied from the cleaning liquid supply nozzle  14  to the front surface of the substrate S and the chemical liquid is supplied from the cleaning liquid supply nozzle  15  to the front surface of the substrate S while the substrate S is rotated in the horizontal direction. In this state, the upper roll-type cleaning member  12  is moved down in a rotation state so as to contact the front surface of the rotating substrate S. Accordingly, the front surface of the substrate S is scrub-cleaned by the upper roll-type cleaning member  12  under the presence of the cleaning liquid (the rinse liquid and the chemical liquid). 
     The length of each of the upper roll-type cleaning member  12  and the lower roll-type cleaning member  13  is set to be slightly longer than the diameter of the substrate S. The upper roll-type cleaning member  12  and the lower roll-type cleaning member  13  are disposed so as to extend in the entire length of the diameter of the substrate S while the axes (the rotation axes) O 1  and O 2  are substantially orthogonal to the axis (that is, the rotation center) O s  of the substrate S. Accordingly, both front and rear surfaces of the substrate S are cleaned at the same time. 
       FIG.  2    is a perspective view illustrating the roll-type cleaning member of the embodiment,  FIG.  3    is a front view illustrating the roll-type cleaning member of the embodiment, and  FIG.  4    is a cross-sectional view taken along the line A-A of  FIG.  3   . As illustrated in  FIGS.  2  to  4   , a roll-type cleaning member  50  having nodules formed on the surface thereof can be used as the upper roll-type cleaning member  12  or the lower roll-type cleaning member  13  of  FIG.  1   . Further, the roll-type cleaning member can be used as both upper and lower roll-type cleaning members. 
     As illustrated in  FIGS.  2  to  4   , the roll-type cleaning member  50  includes a columnar core  51  and a cylindrical sponge member  52  which is fixed to the outer circumferential surface of the core  51 . The sponge member  52  has a shape in which the nodules  54  protrude from a base surface  53  as a surface of a column. The plurality of nodules  54  is arranged in a plurality of lines parallel to the rotation axis direction (the longitudinal direction) a of the roll-type cleaning member  50 . These lines are separated from each other at the same interval in the circumferential direction. The nodules  54  which are adjacent to each other in the circumferential direction are deviated from each other by a half pitch in the rotation axis direction. Thus, when a cross-sectional view in a plane perpendicular to the longitudinal direction is viewed as illustrated in  FIG.  4   , the plurality of nodules  54  is arranged at the same interval in the circumferential direction. In addition, the arrangement of the plurality of nodules is merely an example, and the other arrangement may be employed. 
       FIG.  5 A  is a perspective view of the nodule of the embodiment,  FIG.  5 B  is a diagram illustrating a state where the cleaning surface of the nodule of the embodiment does not contact the substrate, and  FIG.  5 C  is a diagram illustrating a state where the cleaning surface of the nodule of the embodiment contacts the substrate. As illustrated in  FIGS.  2  to  4    and specifically illustrated in  FIGS.  5 A to  5 C , each nodule  54  includes a slit  542  formed on a cleaning surface  541 . Further, in the roll-type cleaning member  50  illustrated in  FIGS.  2  and  3   , all nodules  54  have the slits (the grooves)  542 , but only a part of the nodules  54  provided in the roll-type cleaning member  50  may have the slits  542 . 
     The slit  542  extends in parallel to a direction perpendicular to the rotation direction c of the roll-type cleaning member  50 , that is, the rotation axis direction a of the roll-type cleaning member  50 . As illustrated in  FIGS.  4  and  5 A , the slit  542  has a tapered shape which is narrowed as it goes deeper, and the cross-section thereof is an inverted triangular shape (V-shape). 
     The edge which first contacts the target cleaning surface of the substrate S when the roll-type cleaning member  50  rotates so that the cleaning surface  541  of the nodule contacts the target cleaning surface of the substrate S will be referred to as the “upstream edge”. The side (upstream side) as the upstream edge can be referred to as the “thrust side” and the downstream side thereof can be referred to as the “escape side”. 
     Since the slit  542  is formed, a part of the cleaning surface  541  of the nodule having a columnar shape in the related art is removed. Accordingly, a plurality of upstream edges exists in the rotation direction c of the roll-type cleaning member  50 . Specifically, as illustrated in  FIGS.  5 A to  5 C , each nodule  54  includes a first upstream edge  541   e   1  and a second upstream edge  541   e   2  located at the downstream side in the rotation direction c. 
     As described above, the cleaning effect in the vicinity of the upstream edge of the cleaning surface  541  is higher than that of the other portion. Since the nodule  54  of the embodiment includes a plurality of upstream edges in the rotation direction c as illustrated in  FIG.  5 C , an area (a hatching portion of  FIG.  5 C ) having high cleaning effect can be provided at a plurality of positions. Accordingly, since the upstream edge having high cleaning effect in each nodule  54  scrubs the target cleaning surface of the substrate S twice, the cleaning effect of each nodule  54  is improved compared with the existing nodule. 
     In this way, the slit  542  is formed in the nodule  54  in order to form the second upstream edge  541   e   2 . Thus, the width or the depth of the slit  542  is designed so that the slit  542  in the cleaning surface  541  is not buried by the nodule  54  crushed in the rotation direction c when the target cleaning surface of the substrate S is scrubbed by the rotating nodule  54 . 
     Specifically, when the width of the slit  542  is too narrow and the depth thereof is too deep, the nodule  54  is crushed in the rotation direction c so as to bury the slit  542  when the target cleaning surface of the substrate S is scrubbed. Accordingly, the shape of the slit  542  is designed so that the slit is wide and shallow in order to prevent such a situation. For example, when the height of the nodule  54  is 5 mm and the diameter thereof is 7 mm, the slit  542  is formed so that the width in the cleaning surface  541  is about 1 mm and the depth in the cleaning surface  541  is about 2 mm. Further, since the slit  542  has a V-shape which is narrowed gradually in the depth direction as described above, a deformation of burying the slit  542  hardly occurs. 
       FIG.  6    is a diagram illustrating a state where the nodule scrubs the front surface of the substrate S.  FIG.  6    corresponds to  FIG.  23   . Further,  FIG.  7    is a partially enlarged view of  FIG.  6   . As illustrated in  FIGS.  6  and  7   , each nodule  54  scrubs the substrate S in order from the first upstream edge  541   e   1  to the second upstream edge  541   e   2  located at the downstream side thereof. 
     At this time, comparatively large particles P on the front surface of the substrate S are scraped by the first upstream edge  541   e   1 , and comparatively small particles p are scraped by the second upstream edge  541   e   2 . That is, the first upstream edge  541   e   1  is used for a rough cleaning treatment, and the second upstream edge  541   e   2  subsequent thereto is used for a fine cleaning treatment. Further, as illustrated in  FIG.  6   , the liquid L sufficiently exists in the first upstream edge  541   e   1 , and the liquid L also exists in the second upstream edge  541   e   2 . 
     Since the substrate S is scrubbed by each nodule  54  in order from the first upstream edge  541   e   1  to the second upstream edge  541   e   2  at the downstream side thereof, an excellent cleaning effect is exhibited compared with the case where the existing cylindrical nodule without the slit  542 . This is because of the following reasons. First, each nodule decreases in size when the number of the cylindrical nodules increases. Accordingly, the nodule is easily deformed, and hence a physical force to the substrate decreases. Further, since the first upstream edge  541   e   1  and the second upstream edge  541   e   2  continuously scrub the substrate, the re-adhesion of the particles is suppressed. 
     The configuration of the nodule  54  for forming two upstream edges in the rotation direction is not limited to the above-described configuration.  FIGS.  8 A to  8 F  illustrate another example of a cleaning surface of a nodule provided with two upstream edges in the rotation direction.  FIGS.  8 A to  8 C  illustrate an example in which the slit is formed on the cleaning surface similarly to the above-described embodiment, and  FIGS.  8 D to  8 F  illustrate an example in which a concave portion is formed on the cleaning surface. 
     Specifically, in the example of  FIG.  8 A , a cleaning surface  5411  is provided with two slits  5421   a  and  5421   b  which are parallel to the rotation axis direction a. Accordingly, three upstream edges  5411   e   1  to  5411   e   3  are formed in the rotation direction c. In this way, since three upstream edges  5411   e   1  to  5411   e   3  are provided in the example of  FIG.  8 A , the cleaning effect is further improved. 
     In the example of  FIG.  8 B , the cleaning surface  5412  is provided with a convex circular-arc curved slit  5422  in the rotation direction c. As a result, an upstream edge  5412   e   2  is formed so as to be curved in a convex circular-arc shape in the rotation direction c in addition to the upstream edge  5412   e   1 . Even with this configuration, since two upstream edges  5412   e   1  and  5412   e   2  are provided, the cleaning effect is improved compared with the existing nodule. 
     In the example of  FIG.  8 C , a cleaning surface  5413  is provided with a U-shaped slit  5423  which is bent in a convex shape in the rotation direction c. In other words, in the example of  FIG.  8 C , two slits having different angles are connected at the center of the nodule. As a result, a U-shaped upstream edge  5413   e   2  which is bent in a convex shape in the rotation direction c is provided in addition to the upstream edge  5413   e   1 . Even with this configuration, since two upstream edges  5413   e   1  and  5413   e   2  are formed, the cleaning effect is improved compared with the existing nodule. 
     In the examples of  FIGS.  8 B and  8 C , since the slits  5422  and  5423  have a convex shape in the rotation direction c, dirt inside the slits is scraped out to the left and right sides of the slits by the rotation. 
     In the example of  FIG.  8 D , a cleaning surface  5414  is provided with a concave portion  5424  which has an elongated shape in the rotation axis direction a while both ends are formed in a trapezoidal shape. With this configuration, since the downstream edge of the concave portion  5424  is formed as an upstream edge  5414   e   2  in addition to an upstream edge  5414   e   1  as the upstream edge of the cleaning surface  5414 , the cleaning effect is improved. 
     In the example of  FIG.  8 E , a cleaning surface  5415  is provided with a concave portion  5425  which has an elongated shape in the rotation axis direction a while both ends are formed in a circular-arc shape. With this configuration, since the downstream edge of the concave portion  5425  is formed as an upstream edge  5415   e   2  in addition to an upstream edge  5415   e   1  as the upstream edge of the cleaning surface  5415 , the cleaning effect is improved. 
     In the example of  FIG.  8 F , a cleaning surface  5416  is not formed in a true circular shape, but is formed in an oval shape of which the longitudinal direction is parallel to the rotation axis direction a. The oval cleaning surface  5416  is provided with a concave portion  5426  which has an elongated shape in the rotation axis direction a while both ends are formed in a rectangular shape. Even with this configuration, since the downstream edge of the concave portion  5426  is formed as an upstream edge  5416   e   2  in addition to an upstream edge  5416   e   1  as the upstream edge of the cleaning surface  5416 , the cleaning effect is improved. In this way, the shape of the cleaning surface of the nodule is not limited to the true circular shape, but may be an arbitrary shape including an oval shape, an ellipse shape, and the other polygonal shapes. 
     As illustrated in  FIGS.  8 A to  8 F , slits or concave portions having various shapes can be formed in order to form a further upstream edge in the rotation direction c in addition to the upstream edge as the upstream edge of the cleaning surface  5415 . In the examples of  FIGS.  5 A to  5 C  and  FIGS.  8 A to  8 E , the slits or the concave portion extend so as not to be parallel to the rotation direction c. Here, the length of the second upstream edge in the rotation axis direction a will be described further. 
       FIG.  9    is a diagram illustrating a relation in arrangement between the second upstream edge and the plurality of nodules. As described above, in the roll-type cleaning member  50  of the embodiment, the plurality of nodules  54  is arranged at the same interval in the rotation axis direction a, and the adjacent nodules  54  in the rotation direction c are deviated from each other by a half pitch in the rotation axis direction a. Further, the nodules  54  of the adjacent rows in the rotation axis direction a partially overlap one another. That is, the diameter L 4  of the nodule  54  and the half pitch L 5  of the nodule have a relation of L 4 &gt;L 5 . 
     The overlap width L 2  has a relation of L 2 =L 4 −L 5 . In the overlap portion, the substrate S is also scrubbed by the upper nodule  54  and the substrate S is also scrubbed by the lower nodule  54  of  FIG.  9   . On the contrary, in the non-overlap portion (the width has a relation of L 1 =L 4 −2×L 2 ), the substrate S is scrubbed only by any one of the upper nodule  54  and the lower nodule  54  of  FIG.  9    when the second upstream edge does not exist. 
     Here, it is desirable that the width L 3  of the second upstream edge be larger than the width L 1  of the non-overlap portion. That is, when the adjacent nodules  54  in the rotation direction c have an overlap portion in the rotation axis direction a, it is desirable that the second upstream edge have a length in which the non-overlap portion is covered in the rotation axis direction a. With this configuration, since two rows of nodules pass, two upstream edges also pass by whole of the non-overlap portion, and hence the non-overlap portion is more reliably cleaned. 
     Next, modified examples of the slit will be described with reference to  FIGS.  10  to  13   . In the above-described embodiment, the slit is formed in a V-shape which is narrowed in the depth direction, but the width may be constant in the depth direction as in the slits  5427  and  5428  illustrated in  FIGS.  10 A and  10 B . Further, the bottom of the slit may have a circular-arc shape as in the slit  5427  illustrated in  FIG.  10 A  or may have a rectangular shape as in the slit  5428  illustrated in  FIG.  10 B . In addition to the slit, the width of the concave portion illustrated in  FIGS.  8 C to  8 F  may be narrowed in the depth direction or may be constant in the depth direction as illustrated in  FIGS.  10 A and  10 B . 
     Further, as illustrated in  FIGS.  11 A and  11 B , each nodule may be provided with a plurality of slits. In this case, three or more upstream edges are formed. That is, in the example of  FIG.  11 A , three upstream edges of a first upstream edge  5419   e   1 , a second upstream edge  5419   e   2 , and a third upstream edge  5419   e   3  are formed. Even in the example of  FIG.  11 B , three upstream edges of a first upstream edge  5420   e   1 , a second upstream edge  5420   e   2 , and a third upstream edge  5420   e   3  are formed. 
     The plurality of slits may have the same depth or may have a different depth as illustrated in  FIGS.  11 A and  11 B .  FIG.  11 A  illustrates an example in which an upstream slit  5429   a  is deeper than a downstream slit  5429   b , and  FIG.  11 B  illustrates an example in which an upstream slit  5430   a  is shallower than a downstream slit  5430   b.    
     In this way, since the plurality of slits is formed in a different depth, the contact pressure applied from the plurality of upstream edges to the substrate S can be set differently. That is, when the downstream slit is shallow as illustrated in  FIG.  11 A , the contact pressure of the upstream edge at the downstream side becomes strong. Meanwhile, when the upstream slit is shallow as illustrated in  FIG.  11 B , the contact pressure of the upstream edge at the upstream side becomes strong. Any one of the upstream and downstream edges can be appropriately selected in response to, for example, the kind of the film of the substrate S, the removal target, the cleaning liquid, and the like. 
       FIGS.  12 A and  12 B  are diagrams illustrating another modified example of a nodule including a second upstream edge. As in a nodule  54 ′ illustrated in  FIG.  12 A , a cleaning surface  541 ′ may have a different height before and after a slit  542 ′ in the rotation direction c. In this case, as illustrated in  FIG.  12 A , a contact surface  541   b ′ at the upstream side (the side that contact the cleaning surface of the substrate S first) of the slit may be lower than a contact surface  541   a ′ at the downstream side of the slit  542 ′. Further, as in a nodule  54 ″ illustrated in  FIG.  12 B , a cleaning surface  541   a ″ at the downstream of a slit  542 ″ may be decreased in height from the slit  542 ″ toward the downstream side. 
     According to the nodules  54 ′ and  54 ″, the first upstream edges  541   e   1 ′ and  541   e   1 ″ at the upstream side comparatively strongly scrub the front surface of the substrate S, and the second upstream edges  541   e   2 ′ and  541   e   2 ″ at the downstream side comparatively weakly scrub the front surface of the substrate S. According to the nodule  54 ″, the contact surface  541   a ″ at the downstream side (the escape side) is obliquely cut and the nodule  54 ″ is separated from the substrate S while the contact pressure for the substrate S is weakened, the liquid inside the slit  542 ″ is more reliably discharged. 
       FIGS.  13 A and  13 B  are diagrams illustrating another modified example of the nodule including the second upstream edge. The nodules  54 ′ and  54 ″ illustrated in  FIGS.  13 A and  13 B  are formed by reversing the upstream side and the downstream side of the nodules  54 ′ and  54 ″ illustrated in  FIGS.  12 A and  12 B . According to these examples, the second upstream edges  541   e   2 ′ and  541   e   2 ″ at the downstream side of the first upstream edges  541   e   1 ′ and  541   e   1 ″ at the upstream side strongly contact the front surface of the substrate S. The contact pressure of the first upstream edge at the upstream side can be set to be strong as illustrated in  FIGS.  12 A and  12 B  or the contact pressure of the second upstream edge at the downstream side can be set to be strong as illustrated in  FIGS.  13 A and  13 B  depending on the kind of the film of the substrate S, the removal target, the cleaning liquid, and the like. 
       FIG.  14    is a diagram illustrating a modified example of a relation in direction between the roll-type cleaning member  50  and the slit  542  formed in the nodule  54 . In  FIG.  14   , only one row of the nodules  54  are illustrated, and the other nodules are not illustrated in the drawings. In this example, the slit  542  of the nodule  54  is inclined with respect to the axis direction of the roll-type cleaning member  50 . The inclination angle α can be set to, for example, 10° to 30°. 
     The arrow of  FIG.  14    indicates a direction in which the nodule  54  moves with respect to the substrate. As illustrated in  FIG.  14   , the slit  542  is inclined so as to be located at the upstream side as it moves close to the center C of the roll-type cleaning member  50  in the longitudinal direction. As a result, in  FIG.  14   , the slit  542  of the nodule  54  at the left side of the center C is inclined upward and leftward, and the slit  542  of the nodule  54  at the right side of the center C is inclined upward and rightward. 
     Accordingly, when the second upstream edge contacts the substrate, the roll-type cleaning member  50  first contacts the substrate S from the center C of the rotation axis direction a of the roll-type cleaning member  50 . Then, the dirty liquid inside the slit  542  is discharged from the slit  542  in a direction from the center C of the rotation axis direction a of the roll-type cleaning member  50  outward by the movement of the nodule  54 . In addition, the inclination angle α of the slit  542  with respect to the rotation axis direction a of the roll-type cleaning member  50  may be set in response to the rotation speed of the roll-type cleaning member  50 . Further, the inclination angle α may not be constant in the rotation axis direction a of the roll-type cleaning member  50 , but may have a distribution. 
     2. Second Embodiment: Substrate Cleaning Apparatus Including Pencil-Type Cleaning Member 
       FIG.  15    is a perspective view illustrating an outline of a substrate processing apparatus (a substrate cleaning apparatus) according to a second embodiment. As illustrated in  FIG.  15   , a substrate cleaning apparatus  20  includes a plurality of (in  FIG.  15   , four) spindles  21  (substrate holders) which serves as substrate rotation mechanisms movable in the horizontal direction, supports the circumferential edge of the substrate S so that the front surface of the substrate is directed upward, and rotates the substrate S in the horizontal direction, a column  26  which extends in the vertical direction so as to be elevatable, a swing arm  27  of which one end is rotatably attached to the front end of the column  26  and which extends in the horizontal direction, and a columnar pencil-type cleaning member  28  (a columnar sponge) which is rotatably attached to the lower surface of the other end of the swing arm  27 . Further, two cleaning liquid supply nozzles  24  and  25  are located above the substrate S supported and rotated by a spin chuck  21   a  of a spindle  21  so as to supply the cleaning liquid to the front surface of the substrate S. The cleaning liquid supply nozzle  24  is a nozzle which supplies the rinse liquid (for example, the superpure water) to the front surface of the substrate S, and the cleaning liquid supply nozzle  25  is a nozzle which supplies the chemical liquid to the front surface of the substrate S. 
     The pencil-type cleaning member  28  is held by a holding member (not illustrated), is rotatably provided in the lower surface of the front end of the swing arm  27 , and is rotated (spun) by a driving mechanism (not illustrated) so that the axis is the rotation axis. The rotation axis is perpendicular to the substrate S. The pencil-type cleaning member  28  is formed of, for example, polyurethane foam or PVA. When the swing arm  27  rotates about the column  26 , the pencil-type cleaning member  28  attached to the front end of the swing arm  27  moves on the substrate S while depicting a circular-arc path. Since the front end of the swing arm  27  extends to the center O of the substrate S, the movement path of the pencil-type cleaning member  28  passes through the center O of the substrate S. Further, the pencil-type cleaning member  28  is moved to the outer circumference of the substrate S. Thus, the movement path of the pencil-type cleaning member  28  formed by the rotation of the swing arm  27  becomes a circular-arc shape having a radius as the length of the swing arm  27 , and the movement range is a range from the outer circumference of the substrate S to the center O of the substrate S. 
     At this time, the rinse liquid is supplied from the cleaning liquid supply nozzle  24  to the front surface of the substrate S and the chemical liquid is supplied from the cleaning liquid supply nozzle  25  to the front surface of the substrate S while the substrate S is rotated in the horizontal direction by the substrate rotation mechanism. In this state, the swing arm  27  is rotated so as to revolve while the pencil-type cleaning member  28  is rotated (spun) and the pencil-type cleaning member  28  contacts the front surface of the rotating substrate S. Accordingly, the front surface of the substrate S is scrub-cleaned by the pencil-type cleaning member  28  under the presence of the cleaning liquid (the rinse liquid and the chemical liquid). 
       FIG.  16    is a perspective view of the pencil-type cleaning member  28 ,  FIG.  17 A  is a bottom view of the pencil-type cleaning member  28 , and  FIG.  17 B  is a front view of the pencil-type cleaning member  28 . In  FIGS.  16  and  17 A , the cleaning surface is formed in a hatching shape. As illustrated in  FIGS.  16 ,  17 A, and  17 B , the pencil-type cleaning member  28  is provided with a plurality of (in the embodiment, four) slits  281   a  to  281   d  which continues from one edge to the other edge as a plurality of parallel lines. The slits  281   a  to  281   d  are formed while not being divided between the edges of the pencil-type cleaning member  28 . Further, the depth of the slit becomes deeper as it moves close to the slit near the center of the pencil-type cleaning member  28 . Specifically, in the pencil-type cleaning member  28  of the embodiment, the inner slits  281   b  and  281   c  are deeper than the outer slits  281   a  and  281   d . Further, in the above-described example, the slits  281   a  to  281   d  are formed in a linear shape having a constant width, but may be formed in a curve shape or a shape having a non-constant width. 
       FIG.  18    is a top view illustrating a relation between the substrate S and the pencil-type cleaning member  28 . As described above, the substrate S rotates about the axis, and the pencil-type cleaning member  28  moves on the radial path including the center of the substrate S while rotating about the axis. In the embodiment, it is assumed that the rotation direction of the substrate S and the rotation direction of the pencil-type cleaning member  28  are equal to each other and both the substrate and the pencil-type cleaning member rotate in the counter-clockwise direction in the top view. 
     The substrate S may have a diameter of 300 mm or a diameter of 450 mm. The rotation speed of the substrate S is 250 to 2000 rpm. The specific rotation speed of the substrate S is determined in consideration of the specification of the spindle  21  or the size of the substrate S. The rotation speed of the pencil-type cleaning member  28  about the axis is 0 to 400 rpm and typically 150 to 300 rpm. The specific rotation speed of the pencil-type cleaning member  28  is determined in consideration of the size of the substrate S and the size of the pencil-type cleaning member  28 . The swing speed of the pencil-type cleaning member  28  (the rotation speed of the swing arm  27 ) is 2 to 150 mm/sec, and is determined in consideration of the rotation speed of the substrate S, the size of the substrate S, the rotation speed of the pencil-type cleaning member  28 , and the demanded throughput. 
     The pencil-type cleaning member  28  may scrub-clean the entire front surface of the substrate S by the parallel edge-edge swing of the swing arm  27  moving from one edge of the substrate S to the other edge through the center O of the substrate S. In this case, the pencil-type cleaning member  28  may scrub-clean the entire front surface of the substrate S by the reciprocating swing in which the pencil-type cleaning member  28  reaches the other edge, moves in the opposite direction, and returns to one edge through the center O of the substrate S. Alternatively, the pencil-type cleaning member  28  may scrub-clean the entire front surface of the substrate S by the repeated movement in which the pencil-type cleaning member  28  reaches the other edge, is lifted upward from the front surface of the substrate S, is returned to a position above one edge, is brought into contact with the front surface of the substrate S, and is moved in parallel from one edge of the substrate S to the other edge through the center O of the substrate S by the swing of the swing arm  27 . The swing arm  27  may swing one to ten times in order to clean one substrate S. 
     Further, the pencil-type cleaning member  28  may scrub-clean the entire front surface of the substrate S by the center-edge swing in which the pencil-type cleaning member is moved in parallel from the center of the substrate S to the edge of the substrate S by the swing of the swing arm  27 . Even in this case, the pencil-type cleaning member  28  may move to the center O of the substrate S by the movement in the opposite direction after the pencil-type cleaning member  28  reaches the edge. Alternatively, the pencil-type cleaning member  28  may be operated repeatedly such that the pencil-type cleaning member  28  is lifted upward from the front surface of the substrate S after the pencil-type cleaning member  28  reaches the edge, is returned to a position above the center O of the substrate S, is brought into contact with the front surface of the substrate S, and is moved in parallel from the center O of the substrate S to the edge by the swing of the swing arm  27 . Even in this case, the swing arm  27  may swing one to ten times in order to clean one substrate S. 
     The liquid (the pure water and the rinse liquid) which is supplied from the cleaning liquid supply nozzles  24  and  25  to the center of the substrate S lands on the front surface of the substrate S, and is dispersed on the front surface of the rotating substrate S in the radial direction by the inertia in the supply direction (the direction toward the center of the substrate S) and the centrifugal force (the direction toward the edge of the substrate S) generated by the rotation of the substrate S as illustrated in  FIG.  18   . In this way, a liquid supplied portion in the front surface of the substrate S reaches a cleaning portion formed by the scrubbing of the substrate S and the pencil-type cleaning member  28  due to the rotation of the substrate S, and the substrate S is scrub-cleaned by the pencil-type cleaning member  28  at the cleaning portion under the presence of the pure water and the rinse liquid. 
       FIGS.  19 A to  19 D  are enlarged views of the cleaning portion.  FIGS.  19 A to  19 D  illustrate a state where the pencil-type cleaning member  28  rotates, and also illustrate the slits  281   a  to  281   d  of the pencil-type cleaning member  28 . Further, in the pencil-type cleaning member  28  of  FIGS.  19 A to  19 D , the side surface provided with one end of each of the plurality of slits  281   a  to  281   d  is indicated by H 1 , and the side surface provided with the other end thereof is indicated by H 2 . 
     When the rotation angle of  FIG.  19 A  is set to 0°, the rotation angles of  FIGS.  19 B,  19 C, and  19 D  are respectively set to 45°, 90°, and 135°. As illustrated in  FIGS.  19 A to  19 D , in the rotation angle of 0 to 180°, the liquid flows into the slit from the end of the side surface H 1  of the slits  281   a  to  281   d , and the liquid inside the slit flows out of the end of the side surface H 2 . That is, when the rotation angle of the pencil-type cleaning member  28  is from 0 to 180°, the liquid flows through each of the slits  281   a  to  281   d  in a constant direction (a direction from the side surface H 1  to the side surface H 2 ). 
       FIGS.  20 A to  20 D  illustrate states where the rotation angles are 180°, 225°, 270°, and 315° on the assumption that the rotation angle of the pencil-type cleaning member  28  of  FIG.  19 A  is set to 0°. As illustrated in  FIGS.  20 A to  20 D , when the rotation angle of the pencil-type cleaning member  28  is from 180 to 360°, the liquid flows through each of the slits  281   a  to  281   d  in a constant direction (a direction from the side surface H 2  to the side surface H 1 ). 
     As obvious from  FIGS.  19 A to  19 D  and  FIGS.  20 A to  20 D , the liquid flows through the slits  281   a  to  281   d  in a direction from the side surface H 1  toward the side surface H 2  by the half revolution while the pencil-type cleaning member  28  rotates once, and the liquid flows through the slits  281   a  to  281   d  in the opposite direction, that is, a direction from the side surface H 2  toward the side surface H 1  by the other half revolution. Accordingly, the liquid is sufficiently circulated in the slit so that a fresh liquid is supplied to the slit at all times. 
     Further, in the pencil-type cleaning member  28  of the embodiment, the slits  281   a  to  281   d  are formed on the bottom surface while not being divided from one edge to the other edge. Accordingly, the liquid flowing into the slit does not stay inside the slit unlike when the liquid is divided and not discharged to the outside. For this reason, a fresh liquid is supplied into the slit at all times. 
     Further, since the slits  281   a  to  281   d  are formed on the bottom surface of the pencil-type cleaning member  28 , the edge is formed at both sides. Since the pencil-type cleaning member  28  rotates about the axis and moves in parallel in the radial direction of the substrate S and the substrate S also rotates about the axis, any portion of the slits  281   a  to  281   d  may be the upstream edge. In any case, one of both sides of each of the slits  281   a  to  281   d  becomes the upstream edge. Accordingly, the cleaning effect is improved by the same principle as the first embodiment compared with the case where the slits  281   a  to  281   d  are not formed. 
     In the above-described embodiment, the pencil-type cleaning member  28  is rotated in the same direction as the substrate S. In this case, the front surface of the substrate S and the bottom surface of the pencil-type cleaning member  28  move in the same direction (the forward direction or the follow direction) at the outside of the substrate S in the radial direction of the cleaning portion formed by the contact between the pencil-type cleaning member  28  and the substrate S, and the front surface of the substrate S and the bottom surface of the pencil-type cleaning member  28  move in the opposite direction (the opposed direction or the counter direction) at the inside of the substrate in the radial direction at the cleaning portion. Here, the cleaning effect is increased comparatively at the portion (the inside of the substrate S in the radial direction) in which the front surface of the substrate S and the bottom surface of the pencil-type cleaning member  28  move in the opposed direction at the cleaning portion, and the cleaning effect is decreased comparatively at the portion (the outside of the substrate S in the radial direction) in which the front surface of the substrate S and the bottom surface of the pencil-type cleaning member  28  move in the forward direction. 
     Further, the pencil-type cleaning member  28  may be rotated in the opposite direction to the substrate S. In this case, the front surface of the substrate S and the bottom surface of the pencil-type cleaning member  28  move in the opposite direction at the outside of the substrate S in the radial direction in the cleaning portion, and the front surface of the substrate S and the bottom surface of the pencil-type cleaning member  28  move in the forward direction at the inside of the substrate S in the radial direction at the cleaning portion. Thus, the cleaning effect is increased comparatively at the outside of the substrate S in the radial direction at the cleaning portion, and the cleaning effect is decreased comparatively at the inside of the substrate S in the radial direction at the cleaning portion. 
     Further, the pencil-type cleaning member  28  may not be rotated. In this case, as illustrated in  FIGS.  19 A and  20 A  or  FIGS.  19 C and  20 C , the pencil-type cleaning member  28  may be fixed so that the slits  281   a  to  281   d  form an angle in any one of the radial direction and the circumferential direction of the substrate S. In these cases, the liquid enters each of the slits  281   a  to  281   d  from the upstream side in the rotation direction of the substrate S, and is discharged from the opposite side. 
     When the pencil-type cleaning member  28  is fixed in the direction of  FIGS.  19 A and  20 A , the left edge of each of the slits  281   a  to  281   d  becomes the upstream edge, and hence the cleaning effect is improved. Further, when the pencil-type cleaning member is fixed in the direction of  FIGS.  19 C and  20 C , the upper edge of each of the slits  281   a  to  281   d  becomes the upstream edge, and hence the cleaning effect is improved. In this way, when the pencil-type cleaning member  28  is fixed in the direction of  FIGS.  19 A and  20 A  or  FIGS.  19 C and  20 C , there is a merit that the liquid is circulated inside the slit and the cleaning effect is improved by the plurality of upstream edges. 
     When the pencil-type cleaning member  28  is not rotated, the pencil-type cleaning member  28  may be fixed in a direction in which the slits  281   a  to  281   d  are substantially perpendicular to the radial direction of the substrate S and are substantially parallel to the circumferential direction thereof as illustrated in  FIGS.  19 B and  20 B . In this case, the cleaning effect of the plurality of upstream edges is improved only by the movement (swing) of the pencil-type cleaning member  28  in the radial direction of the substrate S. However, there is an advantage in that the liquid smoothly flows through each of the slits  281   a  to  281   d  and a fresh liquid is supplied into each of the slits  281   a  to  281   d  compared with the other examples. 
     Further, when the pencil-type cleaning member  28  is not rotated, the pencil-type cleaning member  28  may be fixed in a direction in which the slits  281   a  to  281   d  are substantially parallel to the radial direction of the substrate S and are substantially perpendicular to the circumferential direction thereof as illustrated in FIGS.  19 D and  20 D. In this case, the liquid is circulated in each of the slits  281   a  to  281   d  mainly by the movement (swing) of the pencil-type cleaning member  28  in the radial direction of the substrate S. However, there is an advantage in that the cleaning effect of the plurality of upstream edges is improved compared with the other examples. 
     Further, in the above-described embodiment, four slits are formed on the bottom surface of the pencil-type cleaning member  28 , but the number of the slits formed on the bottom surface of the pencil-type cleaning member  28  may be one to three or five or more. For example, other concave portions such as a circular concave portion may be formed in addition to the slit which is formed while not being divided from one edge to the other edge. 
     3. Third Embodiment: Substrate Cleaning Apparatus Including Pencil-Type Buff Processing Member 
     In the above-described first and second embodiments, an example has been described in which the technology is applied to the substrate cleaning apparatus, but the technology can be also applied to a buff processing apparatus which performs a buff processing treatment on a polished substrate. That is, the technology can be applied to a buff processing apparatus as well as a substrate cleaning apparatus that uses a sponge material of PVA. Here, the buff processing treatment includes at least one of a buff polishing treatment and a buff cleaning treatment. The buff processing apparatus may be integrated with or separated from a polishing apparatus. 
     The buff polishing treatment indicates a processing treatment of relatively moving a substrate and a buff processing pad while bringing the buff processing pad into contact with the substrate, and polishing and removing a substrate processing surface through slurry (polishing liquid) between the substrate and the buff processing pad. In general, the buff polishing treatment indicates a processing treatment which is performed as a final polishing treatment after a main polishing treatment performed to flatten unevenness of a surface of a substrate or remove an extra film formed on a surface other than an inner surface of a trench or a via. By the buff polishing treatment, a scratch or foreign matter on a surface of a substrate can be removed, a portion not removed by a main polishing treatment can be additionally removed, or morphology obtained after a main polishing treatment can be improved. 
     Meanwhile, the buff cleaning treatment indicates a finishing treatment performed to reform a surface of a substrate or remove foreign matter on a surface of a substrate by relatively moving a substrate and a buff processing pad while bringing the buff processing pad into contact with the substrate through a cleaning processing liquid (a chemical liquid and/or pure water) between the substrate and the buff processing pad. In the buff cleaning treatment, a strong physical force is applied to a substrate compared with a cleaning treatment using a soft sponge material of PVA. By the use of the buff cleaning treatment, largely adhesive foreign matter which is not removed only by the contact of the sponge material of PVA can be effectively cleaned and removed. 
       FIG.  21    is a perspective view illustrating an outline of a buff processing apparatus of a third embodiment. A buff processing apparatus  30  includes a spin chuck  31  which horizontally rotates the substrate S at a rotation speed necessary for holding the substrate, a rotatable pencil-type buff processing member  32  that is formed by attaching a cleaning member having microscopic holes formed on a surface and formed of polyurethane foam, an elevatable swing arm  33  which holds the pencil-type buff processing member  32  at a front end thereof, a cleaning liquid nozzle  34  which injects a cleaning liquid to the surface of the substrate S, and a cleaning cup  35  which cleans a cleaning tool. The pencil-type buff processing member  32  is supported by the front end of the swing arm  33  through a rotation shaft  36 , and is rotated at a predetermined rotation speed. The pencil-type buff processing member  32  includes a base portion  321  which is fixed to the rotation shaft  36  and a buff processing pad  322  which is attached to the lower portion thereof so as to form the bottom surface of the pencil-type buff processing member  32 . 
     Comparatively large particles are dropped from the substrate S through scrub-cleaning by rinse cleaning or brush cleaning, and the substrate S is carried into the buff processing apparatus  30 . The substrate S is held by the spin chuck  31  while the front surface is exposed upward. The held substrate S is rotated at a predetermined rotation speed and the cleaning liquid is injected from the cleaning liquid supply nozzle  34  to the center of the substrate S. 
     In the swing arm  33 , a downward movement position in which the pencil-type buff processing member  32  is received in the cleaning cup  35  is set to an initial position. Then, the pencil-type buff processing member  32  is self cleaned while rotating inside the cleaning cup  35  filled with the cleaning liquid. The swing arm  33  at the initial position stops the rotation of the pencil-type buff processing member  32 , and moves upward. Then, the pencil-type buff processing member  32  of the front end of the arm is extracted from the cleaning cup  35 , the swing arm  33  is moved to the center of the substrate S, and the bottom surface of the pencil-type buff processing member  32  is pressed against the front surface of the substrate S by the downward movement of the swing arm  33 . At this time, the pencil-type buff processing member  32  starts to rotate at a predetermined rotation speed immediately before the pencil-type buff processing member  32  contacts the substrate S. 
     The buff processing pad  322  of the pencil-type buff processing member  32  independently rotating about the rotation shaft  36  is pressed against the substrate S by the swing arm  33  while contacting the front surface of the substrate S supported and rotated by the spin chuck  31 , and the pencil-type buff processing member  32  is swung from the center of the substrate S to the outer circumference portion at a predetermined speed so as to scrub-clean the front surface of the substrate S. The movement of the swing arm  33  swung to the outer circumference of the substrate S is stopped and the swing arm is moved upward. Then, the pencil-type buff processing member  32  is separated from the front surface of the substrate S. This operation is set as a one-cycle operation. The cleaning treatment can be repeatedly performed by moving the swing arm  33  at the upward movement position in the outer circumference portion of the substrate S to the position of the center of the substrate S again. 
     After the above-described operation is performed once or more, the injection of the cleaning liquid from the cleaning liquid supply nozzle  34  is stopped, and the swing arm  33  is moved so that the pencil-type buff processing member  32  is moved to the upper position of the cleaning cup  35 . Then, the pencil-type buff processing member  32  is moved downward and is rotated inside the cleaning cup  35  so as to be self-cleaned. In this way, the cleaning treatment ends. 
     Immediately after the cleaning treatment ends, the spin chuck  31  is rotated at a high speed under the presence of a dry inert gas so that the cleaned substrate S is dried in a spinning state. When the cleaning treatment is performed by moving the swing arm  33  from the center of the substrate S to the outer circumference portion, the substrate S is rotated by the spin chuck  31  so that a centrifugal force caused by a rotation is applied to contaminated materials or particles existing on the front surface of the substrate S. Accordingly, contaminated materials or particles are scraped off in the same direction as the direction in which the centrifugal force is exerted. 
       FIG.  22    is a longitudinal sectional view of the pencil-type buff processing member  32  of the buff processing apparatus  30 . The pencil-type buff processing member  32  is attached to the lower end of the rotation shaft  36 , and the pencil-type buff processing member  32  includes a base portion  321  and a buff processing pad  322  stuck to the lower surface of the base portion  321 . The buff processing pad  322  is cut into a predetermined size by the use of polishing cloth and is attached to the lower surface of the base portion  321 . The polishing cloth is attached by the use of the adhesive seal of the rear surface thereof. The base portion  321  contacts the rotation shaft  36  at the spherical surface, and hence the polishing cloth uniformly contacts the substrate S even when the substrate is inclined. 
     Generally, the buff processing pad  322  is polishing cloth used to polish a substrate as a mirror surface and a flat surface, and is obtained in a market. For example, a pad (specifically, for example, variations of IC1000 (trademark)/SUBA (trademark) obtained in a market) obtained by laminating rigid polyurethane foam or woven cloth or a suede type pad (specifically, for example, Supreme (trademark) obtained in a market) can be used. The polyurethane foam is porous, and many fine recesses or holes are formed on the surface thereof. 
     In the embodiment, a plurality of (in the embodiment, four) slits  323   a  to  323   d  is formed on the bottom surface of the pencil-type buff processing member  32  similarly to the second embodiment. The slits  323   a  to  323   d  are formed from one edge to the other edge of the pencil-type buff processing member  32  while not being divided. The slits  323   a  to  323   d  are formed in a linear shape having a constant width. As illustrated in  FIG.  22   , the depth of the slit may be equal to or deeper than the depth of the buff processing pad  322 . 
     Since the slits  323   a  to  323   d  are formed in the pencil-type buff processing member  32  in one direction, the supply and the discharge of the processing liquid (slurry or cleaning processing liquid) below the buff processing pad  322  is promoted. When the processing liquid stays below the buff processing pad  322 , a scratch is generated in the buff processing treatment, and hence the substrate is contaminated in the buff cleaning treatment. However, since the supply and the discharge of the liquid are promoted, it is possible to prevent a scratch from being generated in the buff polishing treatment and hence to improve a cleaning effect in the buff cleaning treatment. 
     In addition to the processing liquid supplied from the cleaning liquid supply nozzle  34 , the processing liquid may be also supplied from the center of the buff processing pad  322  through a liquid supply line communicating with opening portions formed in the swing arm  33 , the rotation shaft  36 , and the base portion  321  and the buff processing pad  322  of the pencil-type buff processing member  32 . 
     According to the technology, since the target cleaning surface is scrubbed by the upstream edges of each nodule plural times, there is an effect that the cleaning effect of each nodule is improved. Alternatively, since the bottom surface of the pencil-type processing member scrubbing the surface of the substrate is provided with the slit continuously formed while not being divided from one edge to the other edge, there is an effect that the scrubbing treatment ability on the surface of the substrate is improved. Further, since the liquid supplied to the surface of the substrate easily enters the slit and the liquid is easily discharged from the slit, there is an effect that a fresh liquid is supplied to the slit. Accordingly, the technology is useful for the roll-type processing member or the pencil-type processing member for processing the surface of the substrate by scrubbing the surface of the substrate. 
     While preferred embodiments of the technology have been described, the embodiments can be modified into various forms, and all modified forms within the scope and the spirit of the technology are included in claims.