JP2003179017A - Polisher and polishing pad dressing method therein - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polishing pad dressing method which can dress a polishing pad uniformly and stably. <P>SOLUTION: A dressing method for a polishing pad, in a polisher 10 which polishes a work by bringing the work into contact with a polishing pad 20 while slurry is supplied, includes a step in which the polishing pad 20 is dressed by a first pad dresser 94 and a step in which the polishing pad 20 is dressed by a second pad dresser 96 having a slower pad removing speed than the first pad dresser 94. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polishing apparatus and a method for dressing a polishing pad in the polishing apparatus, and more particularly, to chemical mechanical polishing (CM) equipped with a polishing pad dresser.
P: Chemical Mechanical Polishing) and a dressing method for a polishing pad.

[0002]

2. Description of the Related Art In CMP, dressing (dressing) of a polishing pad is indispensable because clogging of the polishing pad lowers the polishing rate and deteriorates polishing uniformity. Dressing of a polishing pad is performed by bringing a dresser to which abrasive grains such as diamond are adhered into contact with the polishing pad and scraping off the surface of the polishing pad or roughening the surface of the polishing pad, thereby retaining the slurry. This is a treatment for recovering and maintaining the polishing ability.

As this dresser, a dresser to which diamond abrasive grains are electrodeposited has been conventionally used.
7 and 8 show a polishing apparatus 11 equipped with a conventional pad dresser 90A. This pad dresser 90A has diamond abrasive grains 30 electrodeposited on its end surface. The pad dresser 90A is pressed against the polishing pad 20 with the force F while being rotated around the shaft 92 to dress the polishing pad 20.

A pad dresser 90B having a small diameter (generally, an outer diameter of about 100 mm) as shown in FIG. 9 is also used. In the figure, the pad dresser 90
B is supported on one end of the swing arm 80. Further, the other end of the swing arm 80 is rotatably supported by a rotation fulcrum 82.

By swinging the swinging arm 80 and reciprocating the pad dresser 90B between the inner peripheral portion and the outer peripheral portion of the polishing pad 20 at an appropriate speed, the entire surface of the polishing pad 20 is made uniform, that is, The polishing pad 20 can be dressed so that the amount of wear is uniform over the entire surface.

In this case also, the pad dresser 90A
Similarly, the pad dresser 90B is pressed against the polishing pad 20 by the force F while the pad dresser 90B is rotated about the axis to dress the polishing pad 20 (see FIG. 8).

By the way, it is general that after a new polishing pad is attached to the polishing platen and before the polishing operation, the polishing pad is dressed for a predetermined time. The reason for this is that the new polishing pad is not sharpened, the polishing rate is low, and the necessary polishing rate cannot be secured.

The dressing of the polishing pad before the polishing operation with respect to the new polishing pad is usually called "pad startup". In the graph shown in FIG. 10, the transition of the change in the performance of the polishing pad from the time of starting the pad to the end of the life of the polishing pad will be described.

In the figure, the horizontal axis shows the progress of time (the left end is at the start). The left vertical axis represents the polishing rate of the polishing pad (unit: nm / min), and the right vertical axis represents the in-plane uniformity of the polishing rate (unit:%).

When the pad is started up, the polishing rate of the polishing pad is low and the in-plane uniformity of the polishing rate is poor. After that, as you dress the polishing pad,
The polishing rate is gradually increased, and the in-plane uniformity of the polishing rate is also improved. At this point, the startup is completed and the work can be processed.

In addition, at the time of starting the pad, polishing with a dummy work may be performed simultaneously with or separately from the dressing of the polishing pad. This is because the polishing process using the dummy work improves the slurry holding capacity of the polishing pad, and the polishing pad is compressed (compressive deformation is saturated).

While the work is being polished after the pad has been started up, the polishing rate and the in-plane uniformity of the polishing rate are both kept stable for a long period of time. However, although not shown, dressing of the polishing pad is simultaneously performed while polishing is being performed.
Immediately before the life of the polishing pad expires, the polishing rate decreases and the in-plane variation of the polishing rate also increases.

One of the causes of the end of the life of the polishing pad is that the groove formed on the surface of the polishing pad becomes shallow. That is, if the groove formed on the surface of the polishing pad becomes shallow, the transportability of the slurry deteriorates and uniform polishing becomes difficult. In order to avoid such a phenomenon in advance, there are many cases in which the polishing pad is replaced by determining the life of the polishing pad based on the depth of the groove without making a determination based on the decrease in the polishing rate and the in-plane variation of the polishing rate. .

In the life of the polishing pad described above, when the pad is started up, it is the time during which the product is not processed, which is generally called "down time", and efforts are made to shorten it as much as possible. . Further, prolonging the life of the polishing pad is also required from the viewpoint of relative reduction of downtime and reduction of polishing pad cost.

[0015]

However, when the above-mentioned conventional pad dresser 90A or 90B is used, it is difficult to achieve both shortening the pad start-up time and prolonging the polishing pad life.

That is, if a pad dresser having high dressing performance is used, the surface of the polishing pad can be roughened in a short time, and the start-up time can be shortened. However, when such a pad dresser with high dressing performance is used, the abrasion of the polishing pad increases,
The polishing pad has a short life.

On the other hand, if a pad dresser having a low dressing performance is used, the life of the polishing pad can be extended, but the start-up time is long and the downtime cannot be shortened.

As described above, the conventional pad dresser is in a state where the above problems cannot be solved.
The present invention has been made in view of such circumstances, and a polishing device and a polishing device capable of stably starting a polishing pad in a relatively short time and achieving a long polishing pad life at the same time. It is an object of the present invention to provide a pad dressing method.

[0019]

In order to achieve the above object, the present invention relates to a method of dressing a polishing pad in a polishing apparatus for polishing a work by bringing the work into contact with the polishing pad while supplying a slurry. Polishing pad is dressed by the pad dresser, and then the polishing pad is dressed by the second pad dresser whose removal rate of the polishing pad is slower than that of the first pad dresser. And a polishing apparatus therefor.

According to the present invention, the first pad dresser performs the dressing at the time of starting the polishing pad, the entire surface of the polishing pad is dressed in a short time, and thereafter, the removal rate of the polishing pad is slower than that. The polishing pad is dressed with the second pad dresser.
As a result, stable polishing pad dressing can be performed in a relatively short time, and the polishing pad life can be extended.

In the present invention, the removal rate of the polishing pad of the first pad dresser is preferably 2 to 30 times the removal rate of the polishing pad of the second pad dresser. This is because if the ratio of the removal rates of the polishing pads of the first pad dresser and the second pad dresser is within this range, more optimal dressing of the polishing pad can be performed.

The polishing pad removal speed of the pad dresser is represented by a predetermined pressing force, a predetermined speed (plate rotation number), and a thickness of the polishing pad removed per predetermined time,
The above "removal rate ratio" refers to the rate of removal rate under the same conditions.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of a polishing apparatus according to the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 1 is a perspective view showing the overall structure of the polishing apparatus 10. As shown in the figure, the polishing apparatus 10 mainly includes a polishing platen 12 and a wafer holding head 14 which is a holding head for holding a work.

The polishing platen 12 is formed in a disk shape, and a rotating shaft 16 is connected to the center of the lower surface thereof. Polishing surface plate 12
Rotates by driving a motor 18 connected to the rotating shaft 16. A polishing pad 20 is attached to the upper surface of the polishing platen 12, and slurry is supplied onto the polishing pad 20 from a nozzle (not shown).

Next, the structure of the pad dresser used in the present invention will be described with reference to FIGS. In addition, regarding the same and similar members as in FIGS. 1 and 7 to 9,
The same reference numerals are given and the description thereof is omitted. Further, the wafer holding head 14 described with reference to FIG. 1 is generally retracted to the upper side or the side when dressing the polishing pad 20, so that the illustration is omitted.

The pad dresser 84 shown in FIG. 2 is pressed against the polishing pad 20 with a force F while being rotated around the shaft 84A, similarly to the conventional pad dresser 90A shown in FIGS. 7 and 8. Polished pad 2
Dress 0.

The pad dresser 84 supports the first pad dresser 94, the second pad dresser 96, the first pad dresser 94 and the second pad dresser 96, and separates the two types of pad dressers from each other. It is composed of a pedestal 84B having a mechanism for moving it up and down.

As shown in FIG. 3, each of the first pad dresser 94 and the second pad dresser 96 is a cup-shaped grindstone and is formed on the tip portion of the pad dresser body which is the pedestal portion of the cup. It has grindstone portions 94A and 96A. First pad dresser 94 and second
The pad dresser 96 and the pad dresser 96 are formed concentrically. That is, the second pad dresser 96 is arranged on the inner peripheral side of the first pad dresser 94.

The first pad dresser 94 and the second pad dresser 96 have such a mechanism that they can be moved up and down separately (the detailed mechanism is not shown). Therefore, when the second pad dresser 96 is raised, the polishing pad can be dressed by the first pad dresser 94, and when the first pad dresser 94 is raised, the second pad dresser 94 is raised. The polishing pad can be dressed by the dresser 96.

The grindstone portions 94A and 96A, an electrodeposition layer using diamond abrasive grains, or a bond layer (metal bond, vitrified bond or resin bond) in which diamond abrasive grains are dispersed. Appropriate values can be adopted for the grain size and concentration of the diamond abrasive grains, the width of the grindstone portions 94A and 96A, and the like, depending on the material of the polishing pad 20 and the like. In addition, abrasive grains other than diamond may be used in some cases.

The pad dresser 8 shown in FIGS. 4 and 5
6, the pad dresser is supported on the swing arm 80 (the tip end portion and the intermediate portion) similarly to the pad dresser 90B which is the conventional example shown in FIG. Further, the other end of the swing arm 80 is rotatably supported by a rotation fulcrum 82.

In this configuration, the first pad dresser 94
The second pad dresser 96 and the second pad dresser 96 are supported by the same swing arm. That is, the first pad dresser 94 is provided at the tip of the swing arm 80, and the second pad dresser 94 is provided at the middle of the swing arm 80.
The pad dresser 96 of is supported.

In this configuration, the first pad dresser 94 is similar to the pad dresser 84 (see FIGS. 2 and 3).
The second pad dresser 96 and the second pad dresser 96 have a mechanism capable of moving up and down separately (see FIG. 5B).
Therefore, when the second pad dresser 96 is rising, the polishing pad can be dressed by the first pad dresser 94, and the first pad dresser 94 can be dressed.
When the pressure rises, the polishing pad can be dressed by the second pad dresser 96.

Although an example of using an air cylinder is given as the lifting mechanism of the pad dresser shown in the drawing, the lifting mechanism is not limited to this, and lifting mechanisms of various configurations can be adopted. In the illustrated example, the first pad dresser 94 is supported on the tip of the swing arm 80, and the second pad dresser 96 is supported on the middle of the swing arm 80. That is, the second pad dresser 96 may be supported at the tip of the swing arm 80, and the first pad dresser 94 may be supported at the middle of the swing arm 80.

As a means for moving the pad dresser 86 on the polishing pad 20, the same structure as the conventional example shown in FIG. 9 can be used. In this configuration, the swing speed of the swing arm 80 is selected to be an appropriate value for the inner peripheral portion and the outer peripheral portion of the polishing pad 20, so that the final finished state of the surface of the polishing pad 20 will be the optimum state. It is preferable to set. Further, the first pad dresser 94 and the second pad dresser 96 do not have to rotate on their own axis, but it is necessary to provide a driving means so that they can rotate on their own.
It is preferable in terms of the final finished state of the surface.

The polishing pad 20 shown in FIG.
A pure water supply pipe 60 and a slurry supply pipe 62 are arranged on the upper side so that pure water (during pad dressing) and slurry (during polishing) can be supplied, respectively.

The structure of the grindstone portions of the first pad dresser 94 and the second pad dresser 96 is the same as that of the pad dresser 84, and therefore its explanation is omitted.

The pad dresser 88 shown in FIG. 6 is a conventional pad dresser 9 shown in FIG.
Like 0B, the pad dresser is supported by one end of the swing arm 80. Further, the other end of the swing arm 80 is rotatably supported by a rotation fulcrum 82.

In this configuration, the first pad dresser 94
The second pad dresser 96 and the second pad dresser 96 are supported by different swing arms 80A and 80B, respectively. That is, the swing arm 8
A first pad dresser 94 is supported at the tip of 0A, and a second pad dresser 96 is supported at the tip of the swing arm 80B.

In this structure, the pad dresser 84 (see FIGS. 2 and 3) and the pad dresser 86 (FIGS. 4 and 5) are used.
Similarly to the above (see (1)), the first pad dresser 94 and the second pad dresser 96 have such a mechanism that they can be moved up and down separately (not shown). Therefore, the second
When the pad dresser 96 is raised, dressing of the polishing pad can be performed by the first pad dresser 94, and when the first pad dresser 94 is raised, the polishing by the second pad dresser 96 is performed. Pads can be dressed.

Although an example of using an air cylinder is given as an example of the lifting mechanism of the pad dresser shown in the figure, the lifting mechanism of various configurations can be adopted without being limited to this. In addition,
Even if the swinging arm 80A and the swinging arm 80B are fixed to each other at a predetermined angle and are simultaneously driven by the same moving (swinging) mechanism, they move separately (swinging).
It may be configured to be separately driven by a mechanism.

In the case where the swing arm 80A and the swing arm 80B are separately driven by separate moving (swinging) mechanisms, as described above, the first pad dresser 94 is used.
The second pad dresser 96 and the second pad dresser 96 are not provided with a mechanism capable of moving up and down separately, and instead of this, the swing arm 8
0A and the swing arm 80B are separately provided to the polishing pad 2
It is also possible to evacuate from above 0.

As a means for moving the pad dresser 88 on the polishing pad 20, the same structure as the conventional example shown in FIG. 9 can be used. In this configuration, the swing speed of the swing arm 80 is selected to be an appropriate value for the inner peripheral portion and the outer peripheral portion of the polishing pad 20, so that the final finished state of the surface of the polishing pad 20 will be the optimum state. It is preferable to set. Further, the first pad dresser 94 and the second pad dresser 96 do not have to rotate on their own axis, but it is necessary to provide a driving means so that they can rotate on their own.
It is preferable in terms of the final finished state of the surface.

The structure of the grindstones of the first pad dresser 94 and the second pad dresser 96 is the same as that of the pad dresser 84 and the pad dresser 86, and the description thereof will be omitted.

The dressing method of the polishing pad in the polishing apparatus 10 configured as described above is as follows.

In the structure of the pad dresser 84 shown in FIG. 2, first, the polishing platen 12 is rotated in the A direction and the pad dresser 84 is rotated in the B direction. At this time, the second pad dresser 96 is raised and only the first pad dresser 94 is moved to the polishing pad 2.
Set it so that it contacts 0.

Then, water is supplied onto the rotating polishing pad 20 from a nozzle (not shown). As a result, the polishing pad 20 is dressed by the first pad dresser 94 of the pad dresser 84.

Next, the first pad dresser 94 is raised, the second pad dresser 96 is lowered, and the second pad dresser 96 is set so that only the second pad dresser 96 contacts the polishing pad 20. Then, the polishing platen 12 is rotated in the A direction and the pad dresser 84 is rotated in the B direction to perform dressing.

The distribution of the dressing time by the first pad dresser 94 and the dressing time by the second pad dresser 96 may be optimized depending on the dressing conditions, the final finished state of the polishing pad 20, and the like.

In the structure of the pad dresser 86 shown in FIG. 4, first, the polishing surface plate 12 is rotated in the A direction, and the swing arm 80 of the pad dresser 86 is swung about the swing fulcrum 82. At this time, the second pad dresser 96 is raised and set so that only the first pad dresser 94 contacts the polishing pad 20 (see FIG. 5B).

Then, water is supplied onto the rotating polishing pad 20 from a pure water supply pipe 60 (see FIG. 5A).
As a result, the polishing pad 20 is dressed by the first pad dresser 94 of the pad dresser 86.

Next, the first pad dresser 94 is raised, the second pad dresser 96 is lowered, and the second pad dresser 96 is set so that only the second pad dresser 96 contacts the polishing pad 20. Then, the polishing platen 12 is rotated in the A direction, and the swing arm 80 of the pad dresser 86 is rotated.
Is oscillated around the rotation fulcrum 82 to perform dressing.

The distribution of the dressing time by the first pad dresser 94 and the dressing time by the second pad dresser 96 may be optimized depending on the dressing conditions, the final finished state of the polishing pad 20, and the like.

In the structure of the pad dresser 88 shown in FIG. 6, first, the polishing surface plate 12 is rotated in the A direction, and the swing arm 80A of the pad dresser 86 is swung about the swing fulcrum 82. At this time, the second pad dresser 96 is raised or the swing arm 80B supporting the second pad dresser 96 is retracted from the polishing pad 20, and only the first pad dresser 94 is moved to the polishing pad 20. Set it so that it contacts.

Then, water is supplied onto the rotating polishing pad 20 from a nozzle (not shown). As a result, the polishing pad 20 is dressed by the first pad dresser 94 of the pad dresser 88.

Next, the first pad dresser 94 is raised, or the swing arm 80A supporting the first pad dresser 94 is retracted from the polishing pad 20, and the second pad dresser 96 is lowered. The swing arm 80B supporting the second pad dresser 96 is positioned on the polishing pad 20, and is set so that only the second pad dresser 96 contacts the polishing pad 20. Then, the polishing platen 12 is rotated in the A direction, and the swing arm 80B of the pad dresser 86 is swung about the swing fulcrum 82,
Do dressing.

The distribution of the dressing time by the first pad dresser 94 and the dressing time by the second pad dresser 96 may be optimized depending on the dressing conditions, the final finished state of the polishing pad 20, and the like.

The configuration and method described above are examples of the present invention, but the configuration and the like of the present invention are not limited to these, and various configurations and the like can be adopted.

For example, instead of the structure shown in FIGS. 4 and 5 in which two pad dressers are supported by the tip and the intermediate part on the same swing arm 80, a first pad dresser 94 and a second pad dresser 94 are used. Pad dresser 96 (FIGS. 2 and 3) formed on the concentric circles with the pad dresser 96 of FIG.
May be provided on the swing arm 80.

[0061]

EXAMPLES Examples of the present invention will be described below in comparison with comparative examples. The polishing machine used was a platen diameter of 584 m.
The polishing pad used was a CMP polishing machine of m (23 inches), and the polishing pad used was a polishing pad manufactured by Rodel Nitta (product name: IC1000 / SUBA400). The work used was a silicon wafer with an outer diameter of 200 mm (8 inches).

Example 1 The polishing pad 20 was started up in the polishing apparatus 10 having the pad dresser 84 shown in FIGS. 4 and 5. As the first pad dresser 94 used in the pad dresser 84,
An electrodeposition type dresser using diamond abrasive grains having a grain size of # 60 was used. The outer diameter was 100 mm, and the average amount of protrusion of diamond abrasive grains was 40 μm.

The dressing with the first pad dresser 94 was performed in the following two stages. In the first stage, the condition when using the first pad dresser 94 is that the pressing force is 5
6000 Pa. (8 psi) and the number of rotations of the surface plate is 9
0 rpm, rocking of the rocking arm was 3 reciprocations / minute, and pure water was used. In this case, the removal rate of the polishing pad 20 was 1.1 μm / min on average. The dressing time was 5 minutes.

In the second stage, the condition for using the first pad dresser 94 is that the pressing force is 56000 Pa.s. (8
psi), the number of rotations of the platen was 50 rpm, and the swing of the swing arm was 3 reciprocations / minute. In this case, the polishing pad 20
The average removal rate was 1.05 μm / min. Dressing time is 2 minutes per wafer processing,
10 pieces of dummy work were polished. Therefore, the slurry was used instead of pure water.

As the second pad dresser 96, an electrodeposition type dresser using diamond abrasive grains having a grain size of # 100 was used. The outer diameter was 100 mm, and the average amount of protrusion of diamond abrasive grains was 20 μm.

The condition for using the second pad dresser 96 is that the pressing force is 14000 Pa.s. (2 psi), and the rotation number of the platen was 50 rpm. In this case, the removal rate of the polishing pad 20 was 0.15 μm / min on average. The dressing time was set to 2 minutes for processing one wafer, and five dummy works were polished. Therefore,
A slurry was used instead of pure water.

After dressing, the polishing quality of the dummy work was evaluated. The plate thickness before and after the polishing of 49 positions of one work is measured, and the polishing rate (ri, where i = 1 to 49) at each point is obtained, and the average polishing rate Av and the in-plane uniformity Nu shown by the following equations are obtained. Was calculated.

[0068]

[Equation 1]

[0069]

[Equation 2] As a result, Av was 350 nm / min and Nu was 2.5%. This value satisfied the in-house standards of Av> 300 nm / min and Nu <3.0%, which were set as the starting reference value of the polishing pad.

After that, every time a predetermined number (25 sheets) of works were polished, dressing was performed periodically using the second pad dresser 96 under the same conditions as above. as a result,
It was possible to polish 800 or more workpieces in a state where the internal standards of Av> 300 nm / min and Nu <3.0% were satisfied.

Comparative Example 1 In the polishing apparatus 11 having the pad dresser 90B shown in FIG. 9, the polishing pad 20 was started up. As the pad dresser 90B, an electrodeposition type dresser using diamond abrasive grains having a grain size of # 100 was used. The outer diameter was 100 mm, and the average amount of protrusion of diamond abrasive grains was 20 μm.

The dressing was performed in the following two stages. In the first stage, the condition when using the pad dresser 90B is that the pressing force is 28,000 Pa.s. (6 psi), the number of rotations of the surface plate is 50 rpm, the swing of the swing arm is 3 reciprocations / minute,
It was pure water. In this case, the average removal rate of the polishing pad 20 was 0.45 μm / min. The dressing time was 5 minutes.

In the second stage, the pad dresser 90
The condition for using B is that the pressing force is 28,000 Pa.s. (4 ps
i), the number of rotations of the platen was 50 rpm, and the swing of the swing arm was 3 reciprocations / minute. In this case, the removal rate of the polishing pad 20 had an average value of 0.3 μm / min. The dressing time was 2 minutes. In the second stage,
20 pieces of dummy work were polished. Therefore, the slurry was used instead of pure water.

After dressing, the polishing quality of the dummy work was evaluated. The evaluation method was the same as in the example. As a result, Av was 280 nm / min and Nu was 5.1%.
This value does not meet the in-house standards of Av> 300 nm / min and Nu <3.0%, which are defined as the starting reference value of the polishing pad.

Further, under the same conditions, dressing was performed for 2 minutes per wafer processing, and polishing of 20 dummy works was further performed. As a result, Av is 360 nm / min, N
u was 2.1% and came to satisfy the in-house standard.

After that, every time a predetermined number of (25) workpieces were polished, the second pad dresser 96 was used to periodically perform dressing under the same conditions as above (however, the dressing time was 2 minutes). . As a result, Av> 300n
m / min, 2 with Nu <3.0% in-house standards met
At the stage when 50 workpieces were polished, the pad was worn out and the pad life was exhausted.

With respect to the configurations of FIGS. 2 and 3 and the configuration of FIG. 6 as well, a dressing test was performed under substantially the same conditions as above, and a comparison with a conventional device (comparative example) was carried out. The results were obtained.

[0078]

According to the present invention, the first pad dresser is used to perform dressing at the time of startup of the polishing pad, dress the entire surface of the polishing pad in a short time, and thereafter remove the polishing pad from the polishing pad. The polishing pad is dressed by the second pad dresser having a slow moving speed.
As a result, stable polishing pad dressing can be performed in a relatively short time, and the polishing pad life can be extended.

[Brief description of drawings]

FIG. 1 is a perspective view showing the entire structure of a polishing apparatus.

FIG. 2 is a perspective view showing an example of a usage state of a pad dresser used in the present invention.

FIG. 3 is a conceptual diagram showing an example of the configuration of a pad dresser used in the present invention.

FIG. 4 is a perspective view showing another example of a usage state of the pad dresser used in the present invention.

FIG. 5 is a conceptual diagram showing another example of the configuration of the pad dresser used in the present invention.

FIG. 6 is a perspective view showing still another example of the usage state of the pad dresser used in the present invention.

FIG. 7 is a perspective view showing a polishing device including a conventional pad dresser.

FIG. 8 is a front view showing an outline of a conventional pad dresser.

FIG. 9 is a perspective view showing a polishing apparatus having another conventional pad dresser.

FIG. 10 is a graph illustrating changes in the performance of the polishing pad.

[Explanation of symbols]

10 ... Polishing device, 12 ... Polishing platen, 14 ... Wafer holding head, 20 ... Polishing pad, 80 ... Swing arm, 82 ... Rotating fulcrum, 84 ... Pad dresser, 86 ... Pad dresser, 88 ... Pad dresser, 94 ... first pad dresser, 96 ... second pad dresser

Claims (6)

[Claims] 1. A method of dressing a polishing pad in a polishing apparatus for polishing a work by bringing the work into contact with the polishing pad while supplying a slurry, wherein the polishing pad is dressed by a first pad dresser, and then the first pad dresser is used. A dressing method for a polishing pad in a polishing apparatus, wherein dressing of the polishing pad is performed by a second pad dresser having a removal rate of the polishing pad slower than that of the first pad dresser. 2. The method of dressing a polishing pad according to claim 1, wherein the removal rate of the polishing pad of the first pad dresser is 2 to 30 times the removal rate of the polishing pad of the second pad dresser. 3. A polishing apparatus for polishing a work by bringing the work into contact with a polishing pad while supplying a slurry, the polishing apparatus serving as a dressing device for the polishing pad,
A polishing apparatus comprising: a first pad dresser and a second pad dresser having a polishing pad removal rate slower than that of the first pad dresser. 4. The polishing apparatus according to claim 3, wherein the first pad dresser and the second pad dresser are respectively formed on concentric circles. 5. The polishing apparatus according to claim 3, wherein the first pad dresser and the second pad dresser are supported by the same swing arm. 6. The polishing apparatus according to claim 3, wherein the first pad dresser and the second pad dresser are supported by different swing arms.