Abstract:
The present invention provides a pad conditioner for dressing a surface of a polishing pad which is used in a polishing apparatus for polishing works, comprising: a substrate disposed opposite to the polishing pad; a plurality of pellets removably attached to the substrate; and a plurality of linear elastic members which have tip ends and are implanted into the pellets, wherein upon contact of the tip ends of the linear elastic members with the polishing pad, the linear elastic members elastically deform, so that a pressure necessary for conditioning the pad is generated in order to maintain a change in conditioning capability within a predetermined range and have a wide margin for adjusting a height of the conditioner.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to a pad conditioner, a pad conditioning method, and a polishing apparatus, in particular, a pad conditioner which recovers a surface of a polishing pad in a polishing apparatus for polishing a work such as a semiconductor wafer, a polishing apparatus which is provided with the pad conditioner, and a pad conditioning method. 
   2. Description of the Related Art 
   As microstructure and multilayered structure of a semiconductor device have been achieved, CMP (Chemical Mechanical Polishing) technology has become essential in a manufacturing process of the semiconductor device. The CMP technology is now used for planarization of an insulating film between layers, as well as in various processes of Cu wiring and isolation, for example. 
   In the CMP technology for planarization, removal rate uniformity (polishing uniformity) across a work surface is an important specification. In order to improve the polishing uniformity, it is important to uniformly distribute any elements which affect the removal rate across a work surface. 
   While such important elements include a polishing pressure and a relative velocity in polishing, a surface state of a polishing pad is also an important element quantification of which is still in a preliminary stage. A preferable surface state of a polishing pad is achieved by conditioning the polishing pad. Also, a fact that, in a so-called in-situ conditioning in which a pad is conditioned during polishing, for example a stopping of the conditioning suddenly drops a removal rate, shows that a precise control of a surface state of a polishing pad is important. 
   Pad conditioning is an act to bring a pad conditioner having grinders such as diamond into contact with a polishing pad to scrape or roughen a surface of the polishing pad, so that a surface state of a new polishing pad is optimized as an initial state or the slurry holding capacity of the polishing pad in use is recovered to maintain its polishing capability. 
   Conventionally, pad conditioners having diamond abrasive particles electro-deposited thereto have been often used to condition a polishing pad by being pressed against the polishing pad while rotating around its central axis (for example, see Japanese Patent Application Laid-Open No. 2003-211355). 
     FIG. 7  shows a schematic view to illustrate a pad conditioner described in the Japanese Patent Application Laid-Open No. 2003-211355. The pad conditioner  130  described in the Japanese Patent Application Laid-Open No. 2003-211355 includes, as shown in  FIG. 7 , a substrate  131  having diamond abrasive particles  133  electro-deposited thereto, and a supporting section  132  to which the substrate  131  is fixedly attached. 
   In the pad conditioner  130 , the tip ends of the diamond abrasive particles  133  are gradually abraded after repetition of pad conditionings, which in turn gradually reduces the conditioning capability of the conditioner  130 , eventually leading to the end of its life. At the end of the life of the pad conditioner  130 , the used substrate  131  having the abraded diamond abrasive particles  133  electro-deposited thereto is exchanged for a substrate  131  having new diamond abrasive particles  133  electro-deposited thereto. 
   In this case, the exchange of the used substrate for a new one  131  suddenly recovers the pad conditioning capability of the conditioner which will be again gradually lowered, and this generates an unpreferable behavior of the removal rate of a polishing apparatus which dramatically changes from a suddenly recovered level into a lower level over time, as shown by a dotted line of  FIG. 4  which will be explained below. T 1  and T 2  in  FIG. 4  show the timings for exchanging conditioner substrates. 
   In order to sustain this change, various pad conditioners and pad conditioning methods have been proposed (for example, see Japanese Patent Application Laid-Open No. 2004-001152).  FIG. 8  is a schematic view to illustrate a pad conditioner described in the Japanese Patent Application Laid-Open No. 2004-001152. 
   The pad conditioner  120  described in the Japanese Patent Application Laid-Open No. 2004-001152 includes, as shown in  FIG. 8 , a plurality of conditioning pellets  121  having diamond abrasive particles electro-deposited thereto, and a base plate  122  to which each of the pellets  121  are removably and independently attached via a height adjusting device  124 . 
   In this pad conditioner  120 , the used conditioning pellets  121  can be individually exchanged for new conditioning pellets  121  depending on the abraded level of each conditioning pellet  121 , so that a pad can be conditioned by the pad conditioner  120  with the used and new conditioning pellets  121  being simultaneously provided thereto. 
   SUMMARY OF THE INVENTION 
   In the case of the pad conditioner  120  described in the Japanese Patent Application Laid-Open No. 2004-001152, for example, if the exchanged new conditioning pellet  121  has a height different from those of the other conditioning pellets  121 , the influence onto the other conditioning pellets  121  caused by the difference, especially the influence on adjacent conditioning pellets  121 , is not negligible, and may significantly change the conditioning capability of the pad conditioner  120 . 
   Thus, the pad conditioner  120  described in the Japanese Patent Application Laid-Open No. 2004-001152 is provided with a spacer  124  which function as a height adjusting device for each conditioning pellet  121 . However, in order to adjust the heights, the spacer  124 , first of all, needs adjustments by grinding or the like to have an appropriate thickness, which is hard and requires considerable man-hours. 
   Also, the pad conditioner  120  described in the Japanese Patent Application Laid-Open No. 2004-001152 may include conditioning pellets  121  attached to the base plate  122  via an elastic member such as rubber other than the spacer  124 . 
   However, because the elastic member only evenly affects a plurality of diamond abrasive particles electro-deposited to the conditioning pellets  121 , and cannot sufficiently sustain the influence onto the other conditioning pellets  121 , in this case with the elastic member also, an exact height adjustment by a process using the spacer  124  is required. 
   The elastic member has another problem that, when frictional force is applied to the conditioning pellets  121  during conditioning a polishing pad, the member disturbs the orientation of the conditioning pellets  121  which should be in contact with the pad in parallel. In this case, each conditioning pellet  121  intermittently contacts with the polishing pad due to the frictional force, which causes a side effect of a significant inhibition of uniform conditioning. 
   The present invention was made in view of the problems described above, and one of the objects of the present invention is to provide: a pad conditioner which, in conditioning a polishing pad of a polishing apparatus such as a CMP apparatus, is able to maintain a change in conditioning capability within a predetermined range and has a wide margin for adjusting a height of the conditioner, and in which a mounted height of the conditioner does not influence a conditioning pressure much; a pad conditioning method using the same; and a polishing apparatus equipped with the same. 
   In order to achieve the above object, a first aspect of the present invention provides a pad conditioner for dressing a surface of a polishing pad which is used in a polishing apparatus for polishing works, comprising: a substrate disposed opposite to the polishing pad; a plurality of pellets removably attached to the substrate; and a plurality of linear elastic members which have tip ends and are implanted into the pellets, wherein upon contact of the tip ends of the linear elastic members with the polishing pad, the linear elastic members elastically deform, so that a pressure necessary for conditioning the pad is generated. 
   According to the first aspect of the present invention, as a plurality of pellets to which a plurality of linear elastic members are implanted are removably attached to a substrate disposed opposite to a polishing pad, any pellets can be exchanged for new pellets at any time, so that old and new pellets to which a plurality of linear elastic members are implanted are simultaneously provided thereto for conditioning a pad. In addition, the deformation of linear elastic members provides a wide margin for adjustment, which eliminates height adjustments in exchanging pellets. 
   A second aspect of the present invention provides a pad conditioner for dressing a surface of a polishing pad which is used in a polishing apparatus for polishing works, comprising: a supporting section of a solid cylindrical, hollow cylindrical or hog-backed shape having an axis which is disposed parallel to the polishing pad; and a plurality of linear elastic members which have tip ends and are implanted into the circumferential surface of the supporting section, wherein upon contact of the tip ends of the linear elastic members with the polishing pad, the linear elastic members elastically deform, so that a pressure necessary for conditioning the pad is generated. 
   A third aspect of the present invention provides the pad conditioner according to the second aspect of the present invention, further comprising: a rotating device which rotates the supporting section around its central axis; and a controlling device which controls the rotating device to rotate the supporting section around its central axis by a predetermined angle at predetermined time intervals. 
   According to the third aspect of the present invention, because the supporting section of a solid cylindrical or hollow cylindrical shape having a plurality of linear elastic members implanted thereto is rotated around its central axis by a predetermined angle at predetermined time intervals, a part of the plurality of linear elastic members which contribute to the conditioning of a pad can be exchanged for new linear elastic members. 
   A fourth aspect of the present invention provides a pad conditioner for dressing a surface of a polishing pad which is used in a polishing apparatus for polishing works, comprising: a circular substrate disposed in an inclined orientation toward the polishing pad; and a plurality of linear elastic members which are implanted to form a cup shape with the circular substrate, wherein upon contact of the tip ends of the linear elastic members with the polishing pad, the linear elastic members elastically deform, so that a pressure necessary for conditioning the pad is generated. 
   A fifth aspect of the present invention provides the pad conditioner according to the fourth aspect of the present invention, further comprising: a rotating device which rotates the circular substrate around its central axis that is perpendicular to the substrate at the center thereof; and a controlling device which controls the rotating device to rotate the circular substrate around its central axis by a predetermined angle at predetermined time intervals. 
   According to the fifth aspect of the present invention, because the circular substrate having a plurality of linear elastic members implanted thereto to form a cup shape is rotated by a predetermined angle at predetermined time intervals around its central axis which is perpendicular to the substrate at the center thereof, a part of the plurality of linear elastic members which contribute to the conditioning of a pad can be exchanged for new linear elastic members. 
   A sixth aspect of the present invention provides the pad conditioner according to any one of the first to fifth aspects of the present invention, wherein each of the plurality of linear elastic members includes a tip end to which a tip piece is fixed, the tip piece being made of a material having high hardness and wear resistance. 
   According to the sixth aspect of the present invention, due to the tip pieces fixed to each tip end of the linear elastic members, which are made of a material having high hardness and wear resistance, a pad can be efficiently conditioned with less abrasion of the conditioner. This allows the conditioner to be maintained to constantly grind an amount of a pad. 
   A seventh aspect of the present invention provides a polishing apparatus, comprising the pad conditioner according to any one of the first to sixth aspects of the present invention. According to the seventh aspect of the present invention, polishing can be well achieved with less change in removal rates. 
   An eighth aspect of the present invention provides a pad conditioning method for dressing a surface of a polishing pad which is used in a polishing apparatus for polishing works, comprising: using the pad conditioner according to any one of the first to sixth aspects of the present invention; and exchanging a part of the plurality of linear elastic members which contribute to the conditioning of the pad for new linear elastic members at predetermined time intervals, so that a change in pad conditioning capability of the pad conditioner is maintained within a predetermined range. 
   According to the eighth aspect of the present invention, because a part of the plurality of linear elastic members which contribute to the conditioning of a pad are exchanged for new linear elastic members to maintain a change in pad conditioning capability of the pad conditioner within a predetermined range, polishing can be well achieved with less change in removal rates. 
   A ninth aspect of the present invention provides a pad conditioning method for dressing a surface of a polishing pad which is used in a polishing apparatus for polishing works, comprising: using the pad conditioner according to the first aspect of the present invention; and exchanging a part of the plurality of linear elastic members which contribute to the conditioning of a pad for new linear elastic members at predetermined time intervals by exchanging the pellets at predetermined time intervals, so that a change in pad conditioning capability of the pad conditioner is maintained within a predetermined range. 
   According to the ninth aspect of the present invention, because the exchange of pellets at predetermined time intervals eliminates height adjustments, and a change in pad conditioning capability of the pad conditioner is easily maintained within a predetermined range, polishing can be well achieved with less change in removal rates. 
   A tenth aspect of the present invention provides a pad conditioning method for dressing a surface of a polishing pad which is used in a polishing apparatus for polishing works, comprising: using the pad conditioner according to the third aspect of the present invention; and exchanging a part of the plurality of linear elastic members which contribute to the conditioning of a pad for new linear elastic members at predetermined time intervals by rotating the supporting section around its central axis at predetermined time intervals, so that a change in pad conditioning capability of the pad conditioner is maintained within a predetermined range. 
   An eleventh aspect of the present invention provides a pad conditioning method for dressing a surface of a polishing pad which is used in a polishing apparatus for polishing works, comprising: using the pad conditioner according to the fifth aspect of the present invention; and exchanging a part of the plurality of linear elastic members which contribute to the conditioning of a pad for new linear elastic members at predetermined time intervals by rotating the circular substrate around its central axis which is perpendicular to the substrate at the center thereof at predetermined time intervals, so that a change in pad conditioning capability of the pad conditioner is maintained within a predetermined range. 
   According to the tenth or eleventh aspect of the present invention, because a part of the plurality of linear elastic members which contribute to the conditioning of a pad can be automatically exchanged for new linear elastic members even during polishing at predetermined time intervals so that a change in pad conditioning capability of the pad conditioner is maintained within a predetermined range, polishing can be well achieved with less change in removal rates. 
   As described above, according to a pad conditioner and a pad conditioning method of the present invention, a change in pad conditioning capability of the pad conditioner is maintained within a predetermined range, and a wide margin of height adjustments is assured, thereby a mounted height of a conditioner does not influence much on a conditioning pressure. Also, according to a polishing apparatus of the present invention, a process on a work can be well achieved with excellent removal rate uniformity across a work surface. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective view to show an embodiment of a polishing apparatus according to the present invention; 
       FIG. 2  is a side view to show a configuration of a pad conditioner according to the present invention; 
       FIG. 3  is a top plan to show a configuration of a pad conditioner according to the present invention; 
       FIG. 4  is a graph to illustrate changes of removal rates; 
       FIG. 5  is a schematic view to show a configuration of a pad conditioner according to the second aspect of the present invention; 
       FIG. 6  is a schematic view to show a configuration of a pad conditioner according to the third aspect of the present invention; 
       FIG. 7  is a schematic view to show a conventional pad conditioner; and 
       FIG. 8  is a side view to show another conventional pad conditioner. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Now, preferable embodiments of a pad conditioner, a pad conditioning method, and a polishing apparatus according to the present invention will be explained below in detail with reference to the accompanying drawings. Throughout the drawings, similar reference numerals or characters are used to designate the similar members. 
     FIG. 1  is a perspective view to show an embodiment of a polishing apparatus according to the present invention. A polishing apparatus  10  of  FIG. 1  generally includes a polishing plate  12 , a wafer carrier  14 , and a pad conditioner  30 . 
   The polishing plate  12  has a rotating shaft  16 , and a driving of a motor  18  which is coupled to the shaft  16  causes the polishing plate  12  to rotate in a direction shown by the arrow A in  FIG. 1 . The wafer carrier  14  holding a work of wafer has a rotating shaft  22 A, and a driving of a motor (not shown) which is coupled to the shaft  22 A causes the wafer carrier to rotate in a direction shown by the arrow B in  FIG. 1 . The polishing plate  12  has an upper surface onto which a polishing pad  20  is attached, and slurry is supplied from a slurry supply nozzle (not shown) over the polishing pad  20 . 
   The pad conditioner  30  is pressed against a surface of the rotating polishing pad  20  to condition the surface to maintain its polishing capability, by optimizing the surface of the polishing pad  20  as an initial state when the pad is a new one, or cleaning clogging of the surface of the polishing pad  20  when the pad is in use so that the slurry holding capacity of the polishing pad is recovered. 
     FIG. 2  and  FIG. 3  are schematic views to show a pad conditioner  30  according to the present invention.  FIG. 2  is a side view; and  FIG. 3  is a top plan view. The pad conditioner  30  generally includes a disc-like substrate  32 , and six pellets  34  to which a number of linear elastic members  31  are planted (hereinafter, it may be referred to as “implanted” which is more suitable to the image). The number of the pellets  34  is not limited to six. 
   Each pellet  34  is removably attached to the substrate  32  by a fixing screw  33 . Each linear elastic member  31  has a tip end to which a tip piece  31   a  is fixedly attached. The linear elastic members  31  may be preferably piano wires, carbon fibers, and the like. 
   The tip pieces  31   a  fixedly attached to the tip ends of the linear elastic members  31  are preferably made of a material having high hardness and wear resistance, and diamond abrasive particles or the like are fixed to the tip pieces  31   a  by electro-deposition. In stead of the diamond abrasive particles, WC or cemented carbide may be used. 
   When carbon fibers having high hardness are used for the linear elastic members  31 , the tip ends themselves of the carbon fibers may be used for conditioning without fixedly attaching the tip pieces  31   a  thereto. 
   In order to implant (plant) the linear elastic members  31  into the pellets  34 , as one method, the linear elastic members  31  may be inserted into holes which are formed in the pellets  34  so as to be adhesively secured therein, but other methods including spot welding may be used. 
   In the pad conditioner  30  according to the present invention, a conditioning pressure P can be represented by the following formula (1), where a Young&#39;s modulus of the elastic member  31  is E, an effective flexible length of the elastic member  31  is L, a thickness of the elastic member  31  is t, a width of the elastic member  31  is b, a coefficient of friction between the tip piece  31   a  and the polishing pad  20  is μ, a displacement in a horizontal direction, and a horizontal displacement caused by deflection of the elastic member  31  is δ. 
   
     
       
         
           
             
               
                 P 
                 = 
                 
                   
                     
                       Ebt 
                       3 
                     
                     ⁢ 
                     δ 
                   
                   
                     6 
                     ⁢ 
                     
                       ( 
                       
                         
                           δ 
                           2 
                         
                         + 
                         
                           L 
                           2 
                         
                       
                       ) 
                     
                     ⁢ 
                     
                       ( 
                       
                         
                           μ 
                           ⁢ 
                           
                               
                           
                           ⁢ 
                           L 
                         
                         + 
                         δ 
                       
                       ) 
                     
                   
                 
               
             
             
               
                 ( 
                 1 
                 ) 
               
             
           
         
       
     
   
   Even when a surface waviness of the polishing pad  20  is 50 μm, optimization of the values of E, L, t, and b of the elastic member  31  makes the variation in the conditioning pressures P less than 1%. 
   In order to condition the polishing pad  20 , the tip pieces  31   a  of the pad conditioner  30  are brought into contact with the surface of the rotating polishing pad  20 , and then the substrate  32  is approached to the polishing pad  20  by a predetermined distance so that the linear elastic members  31  are bended. The elastic deformation of the linear elastic members  31  creates a conditioning pressure which makes the surface of the polishing pad  20  to be conditioned. In this case, the amount of bending of the linear elastic members  31  can be adjusted to obtain an optimal conditioning pressure. 
   The tip pieces  31   a  follow the different heights of the surface of the polishing pad  20  caused by the surface waviness, and a stress variation which corresponds to a variation in the amount of bending of the linear elastic members  31  caused by the following is small, thereby a more uniform conditioning over the surface of the polishing pad  20  can be achieved. 
   As shown in  FIG. 1 , rotating the substrate  32  by the motor  37  causes all of the pellets  34  to operate the conditioning uniformly. Also as shown in  FIG. 1 , the pad conditioner  30  is mounted to an arm  26  which is fixed to a rotating shaft  25 , and is moved in a reciprocating manner between a central portion and a peripheral portion of the polishing pad  20  to condition the polishing pad  20 , which improves the uniformity of conditioning across the polishing pad surface. 
   The pad conditioning is a so called in-situ conditioning which is simultaneously performed with polishing of a work of wafer, and sharp edges of the operating tip pieces  31   a  of the linear elastic members  31  will be abraded over time. Thus, the pellets  34  are exchanged for new pellets  34  at predetermined time intervals. 
   In exchanging the pellets  34 , for example, the pellets  34  at A and D positions in  FIG. 3  are exchanged at the exchange timing t 1  in  FIG. 4  which will be explained below, the pellets  34  at B and E positions in  FIG. 3  are exchanged at the next exchange timing t 2 , the pellets  34  at C and F positions in  FIG. 3  are exchanged at the next exchange timing t 3 , and so on. This makes the old and new pellets  34  constantly provided together for conditioning a pad with the tip pieces  31   a  of the number of linear elastic members  31  which are of different abrasion levels. 
   Since only a part of the pellets  34  are exchanged at one time among the all, a change in the removal rate caused by the exchanging is small.  FIG. 4  is a graph to show the change. In  FIG. 4 , the horizontal axis represents number of polished wafers and timings to exchange conditioners, and the vertical axis represents removal rate. 
   The removal rates of a wafer when the pellets  34  are exchanged at the exchange timings t 1 , t 2 , . . . are shown in a solid line in  FIG. 4 . The peak removal rates (the top points of curves) are limited to about 70% of the removal rates at the conventional timings T 1  and T 2  when all of the conditioners are exchanged (a dotted curve in  FIG. 4 ), but the change widths of the removal rates are extremely smaller compared to those in the case in which all of the conditioners are exchanged. 
   In the present invention, the linear elastic members  31  are used, and due to the stress caused by the bended linear elastic members  31 , a conditioning pressure is generated. However, a change in the bending is reflected into a less change of conditioning pressures, thereby an exchange of some pellets  34  causes almost no influence onto adjacent pellets  34 , which eliminates the height adjustments of linear elastic members  31  due to the exchange. This makes the exchanges easy and the apparatus may be stopped for the exchanges only for a short period of time. 
   Therefore, in the pad conditioning method according to the present invention, since the pad conditioning capability is under the maximum limit (e.g. 70%), and also the change width of the pad conditioning capability is limited to a small amount, the pad conditioner can be stable with a long life. 
     FIG. 5  is a schematic view to show an embodiment of a pad conditioner  30 A according to the second aspect of the present invention. The pad conditioner  30 A generally comprises: a supporting section  32 A of a solid cylindrical, hollow cylindrical or hog-backed shape; a plurality of linear elastic members  31  which have tip ends and are implanted into a circumferential surface  32   a  of the supporting section  32 A; a rotating device  35  connected to a central axis  32   b  of the supporting section  32 A for rotating the supporting section  32 A around the central axis  32   b ; and a controlling device  36  which controls the rotation of the rotating device  35 . 
   Each linear elastic member  31  has a tip end to which a tip piece  31   a  is fixedly attached. The supporting section  32 A has a central axis  32   b  which is disposed parallel to a surface of a polishing pad  20 , and is configured so that a conditioning pressure is generated when the tip pieces  31   a  of the linear elastic members  31  facing toward the surface of a polishing pad  20  are brought into contact with the polishing pad  20  and the linear elastic members  31  are bended. 
   The linear elastic members  31  may be preferably piano wires, carbon fibers, and the like, i.e., are members that can be described as strands. The tip pieces  31   a  fixedly attached to the tip ends of the linear elastic members  31  are preferably made of a material having high hardness and wear resistance, and diamond abrasive particles or the like are fixed to the tip pieces  31   a  by electro-deposition. Instead of the diamond abrasive particles, WC or cemented carbide may be used. 
   When carbon fibers having high hardness are used for the linear elastic members  31 , the tip ends themselves of the carbon fibers may be used for conditioning without fixedly attaching the tip pieces  31   a  thereto. 
   In order to implant (plant) the linear elastic members  31  into the pellets  34 , as one method as in the previous aspect of the present invention, the linear elastic members  31  may be inserted into holes which are formed in the pellets  34  so as to be adhesively secured therein, but other methods including spot welding may be used. 
   In a pad conditioning, the controlling device  36  controls the rotating device  35  such as a motor to rotate the supporting section  32 A by a predetermined angle at predetermined time intervals. This allows the plurality of abraded tip pieces  31   a  to be separated from the polishing pad  20 , and then this part of the tip pieces  31   a  are exchanged for a plurality of new tip pieces  31   a  which contribute to pad conditioning, so that the old and new tip pieces  31   a  can be constantly provided together for conditioning a pad. Thus, a change in pad conditioning capability can be maintained within a small range, and a change in removal rates also can be limited to a small amount. 
   The partial exchange of the old and new linear elastic members  31  which contribute to pad conditioning can be automatically performed during polishing of a work of wafer, which allows the wafer to be consistently polished at a generally constant removal rate. 
     FIG. 6  is a schematic view to show an embodiment of a pad conditioner  30 B according to a third aspect of present invention. The pad conditioner  30 B generally comprises a circular substrate  32 B having a circular substrate surface  32   e  and a central axis  32   g  which is perpendicular to the circular substrate surface  32   e  at the center of the circle  32   f ; a number of linear elastic members  31  which are implanted to form a cup shape with the circular substrate surface  32   e , a rotating device  35  disposed along the central axis  32   g  to rotate the circular substrate  32 B around the central axis  32   g ; and a controlling device  36  which controls the rotation of the rotating device  35 . 
   Each linear elastic member  31  has a tip end to which a tip piece  31   a  is fixedly attached. The circular substrate  32 B is disposed so that the circular substrate surface  32   e  is oriented at an angle to a surface of the polishing pad  20 , and is also disposed so that a conditioning pressure is generated when the tip pieces  31   a  of the linear elastic members  31  are brought into contact with the surface of the polishing pad  20  and the linear elastic members  31  are bended. 
   As in the previous aspect of the present invention, the linear elastic members  31  may be preferably piano wires, carbon fibers, and the like. The tip pieces  31   a  fixedly attached to the tip ends of the linear elastic members  31  are preferably made of a material having high hardness and wear resistance, and diamond abrasive particles or the like are fixed to the tip pieces  31   a  by electro-deposition. In stead of the diamond abrasive particles, cemented carbide may be used. 
   When carbon fibers having high hardness are used for the linear elastic members  31 , the tip ends themselves of the carbon fibers may be used for conditioning without fixedly attaching the tip pieces  31   a  thereto. 
   In order to implant (plant) the linear elastic members  31  into the pellets  34 , as one method as in the previous aspect of the present invention, the linear elastic members  31  may be inserted into a number of holes which are formed in the pellets  34  so as to be adhesively secured therein, but other methods including spot welding may be used. 
   In a pad conditioning, the controlling device  36  controls the rotating device  35  such as a motor to rotate the circular substrate  32 B by a predetermined angle at predetermined time intervals. This allows the plurality of abraded tip pieces  31   a  to be separated from the polishing pad  20 , and then this part of the tip pieces  31   a  are exchanged for a plurality of new tip pieces  31   a  which contribute to pad conditioning, so that the old and new tip pieces  31   a  can be constantly provided together for conditioning a pad. Thus, a change in pad conditioning capability can be maintained within a small range, and a change in removal rates also can be limited to a small amount. 
   The partial exchange of the old and new linear elastic members  31  which contribute to pad conditioning can be automatically performed during polishing of a work of wafer, which allows the wafer to be consistently polished at a generally constant removal rate. 
   As described above, according to a pad conditioner and a pad conditioning method using the same of the present invention, a pad conditioner the mounted height of which does not influence a conditioning pressure much and a pad conditioning method which makes a pad conditioner have a long life and a small change in pad conditioning capability can be provided. 
   According to the polishing apparatus  10  of the present invention, since the polishing apparatus  10  includes the pad conditioner which performs such a pad conditioning, a polishing can be well done at a stable removal rate in the polishing apparatus  10 .