JP2015030058A - Dressing method and dressing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dressing method and a dressing apparatus capable of suppressing generation of particles and extending a life of an abrasive pad by suppressing abrasion of the abrasive pad while appropriately roughening an abrasive surface of the abrasive pad.SOLUTION: A dressing method for dressing an abrasive pad for abrading a wafer bonded onto a surface plate, by pressing a brush and a plate on the abrasive pad to slidably contact the brush and the plate with the abrasive pad, includes: simultaneously pressing a tip end of the brush and the plate on the abrasive pad after setting the tip end of the brush into a state of protruding from a dressing target surface slidably contacting the abrasive pad; and dressing the abrasive pad.

Description

  The present invention relates to a dressing method and a dressing apparatus for a polishing pad.

  In recent years, as devices formed on semiconductor wafers have been miniaturized and multilayered, CMP (Chemical Mechanical Polishing) technology for planarizing semiconductor wafers has become an indispensable technology that must be present in the manufacturing process of semiconductor wafers. It has become. One of the important factors in CMP is the uniformity of the polishing rate within the work surface (polishing uniformity). In order to improve the polishing uniformity, it is important to uniformly distribute elements that affect the polishing rate within the work surface.

  Factors affecting the polishing rate include the polishing pressure and the relative speed of polishing. An important factor that has not been quantified has been the surface state of the polishing surface of the polishing pad. A preferable surface state of the polishing surface of this polishing pad is formed by pad dressing (hereinafter simply referred to as dressing).

  Dressing is performed by bringing a pad dresser (hereinafter simply referred to as a dresser or a dressing device) provided with a grindstone such as diamond into contact with the polishing pad. As a result, the surface of the polishing pad is scraped or roughened to improve the retention of the unused polishing pad slurry so that it can be polished, or the retention of the polishing pad slurry in use can be improved. It is possible to recover and maintain the polishing ability. By maintaining the polishing ability of the polishing pad by such dressing, the flatness of the polished wafer can be improved.

JP 2000-237948 A Japanese Patent Laid-Open No. 9-254019

  Patent Document 1 and Patent Document 2 describe a dresser provided with a brush for scraping out foreign substances clogged in a recess of a polishing surface of a polishing pad. Nylon is often used as the brush material. Although this brush alone can scrape off foreign matter on the polishing surface of the polishing pad, it has little effect on cutting.

  Conventionally, brushes have been used for the purpose of scraping off foreign substances clogged in the recesses of the polishing surface. Therefore, when performing dressing for scraping the polishing pad, a diamond dresser having a high ability to scrape the polishing pad is used. A diamond dresser is a dresser in which diamond abrasive grains are electrodeposited on a substrate. By using such a dresser, as described above, the polishing ability of the polishing pad can be maintained, and a wafer with high flatness can be obtained by polishing.

  However, when dressing using hard abrasive grains such as diamond, the ability to scrape the surface of the polishing pad is too high, so the polishing pad is greatly worn and a large amount of particles are generated.

  In the case of a diamond dresser, the dressing capacity depends on the number of introduced diamond abrasive grains per unit area, the roughness (count) of the diamond abrasive grains, the size, the dresser pressure, and the dressing time. The number, roughness, and size of the diamond abrasive grains, which are the structure of the diamond dresser itself, are basically adjusted by the manufacturer and hardly change depending on the condition of the polishing cloth.

  Since the diamond abrasive has a high ability to scrape the polishing pad, the dressing time is often several seconds when used for a soft polishing pad. This often results in partial dressing rather than the entire polishing pad. By performing a partial strong dressing, the polishing pad itself or a clogged polishing pad adheres to the wafer surface being polished and is detected as particles. For this reason, when dressing is performed using a diamond dresser, extremely many particles are generated on the polishing pad.

  In recent years, the cleanliness of the wafer surface required with the miniaturization of devices has increased. Furthermore, the ability to detect fine particles in the wafer surface observation apparatus after polishing has increased, and even particles with a diameter of about several tens of nanometers have been detected, and even fine particles have become a problem. I came. Therefore, a dresser that generates a large amount of particles, such as a diamond dresser, is not desirable for polishing semiconductor wafers in recent years.

  As described above, when a diamond dresser is used, the polishing surface of the polishing pad can be roughened, and a wafer with high flatness can be obtained, but since a large amount of particles are generated, the cleanliness of the wafer surface is deteriorated. There is a problem. Further, since the wear amount of the polishing pad is large, there is a problem that the life of the polishing pad is shortened.

  The present invention has been made in view of the above-described problems, and suppresses the generation of particles by suppressing the abrasion of the polishing pad while appropriately roughening the polishing surface of the polishing pad, thereby improving the life of the polishing pad. It is an object of the present invention to provide a dressing method and a dressing device that can be used.

  In order to achieve the above object, according to the present invention, a dressing method for dressing a polishing pad by pressing and sliding a brush and a plate against a polishing pad for polishing a wafer attached on a surface plate The tip of the brush is protruded from the dress surface that is in sliding contact with the polishing pad of the plate, and the tip of the brush and the plate are simultaneously pressed against the polishing pad to make sliding contact, thereby dressing the polishing pad. A dressing method is provided.

  In this way, the tip of the brush protruding from the dress surface of the plate can be cut in a direction perpendicular to the polishing surface of the polishing pad. Further, since the polishing surface is roughened using a soft brush, wear of the polishing pad can be suppressed. As a result, generation of particles from the polishing pad can be suppressed and the life of the polishing pad can be improved while moderately roughening the polishing surface of the polishing pad.

At this time, it is preferable that the length at which the tip of the brush protrudes from the dress surface is 1 mm or less.
This ensures that the tip of the brush can be cut into the polishing pad. As a result, the polishing surface of the polishing pad can be reliably roughened while suppressing the generation of particles from the polishing pad.

At this time, the brush is preferably made of synthetic fiber nylon, and the material of the plate which does not contaminate the wafer with metal can be used.
In this way, it is possible to prevent the polishing pad from being contaminated by metal impurities from the brush and the plate. As a result, a wafer with higher cleanliness can be obtained.

Further, as the material of the plate, a material made of ceramics or DLC (diamond-like carbon) can be used.
If a plate made of such a material is used, it is a material excellent in chemical resistance and wear resistance, so that impurity contamination and generation of particles from the plate can be suppressed.

  According to the present invention, there is also provided a dressing device for dressing a polishing pad for polishing a wafer attached on a surface plate, comprising a brush and a plate, and the brush and the plate are attached to the polishing pad. The polishing pad is dressed by being pressed and slidably contacted, and the tip of the brush protrudes from the dress surface of the plate in sliding contact with the polishing pad, and the tip of the brush and the plate are connected to the polishing pad. There is provided a dressing device characterized in that it is pressed against and slidable simultaneously to dress the polishing pad.

  If it is such, the tip of the brush protruding from the dress surface of the plate can be cut in a direction perpendicular to the polishing surface of the polishing pad. Moreover, since the surface is roughened using a soft brush, abrasion of the polishing pad can be suppressed. As a result, it is possible to suppress the generation of particles from the polishing pad and improve the life of the polishing pad while appropriately roughening the polishing surface of the polishing pad.

It is preferable that the length at which the tip of the brush protrudes from the dress surface is 1 mm or less.
This ensures that the tip of the brush can be cut into the polishing pad. As a result, the polishing surface of the polishing pad can be reliably roughened while suppressing the generation of particles from the polishing pad.

At this time, the brush is preferably made of synthetic fiber nylon, and the material of the plate may not contaminate the wafer with metal.
In this way, it is possible to prevent the polishing pad from being contaminated by metal impurities from the brush and the plate. As a result, a wafer with higher cleanliness can be obtained.

Furthermore, the material of the plate may be made of ceramics or DLC (diamond-like carbon).
A plate made of such a material is excellent in chemical resistance and wear resistance, and therefore can suppress impurity contamination and particle generation from the plate.

  With the dressing method and dressing apparatus of the present invention, the polishing surface of the polishing pad can be appropriately roughened with a brush. Furthermore, since the abrasion amount of the polishing pad can be suppressed, the generation of particles can be suppressed and the life of the polishing pad can be improved.

It is the schematic at the time of applying the dressing apparatus of this invention to the dressing of the polishing pad of a double-side polish apparatus. It is the schematic which shows an example of the dressing apparatus of this invention. It is the schematic at the time of applying the dressing apparatus of this invention to the dressing of the polishing pad of a single-side polish apparatus. It is the schematic which shows another example of the dressing apparatus of this invention. It is a figure which shows the flatness level of the wafer outermost periphery part in an Example and Comparative Examples 1 and 2. FIG. It is a figure which shows the relative number of the particle | grains in an Example. It is a figure which shows the surface roughness of the polishing pad in an Example. It is a figure which shows the relative groove depth of the polishing pad in an Example and Comparative Example 1-3. It is a figure which shows the relative number of the particle in the comparative example 1. 5 is a diagram showing the surface roughness of a polishing pad in Comparative Example 1. FIG. 6 is a diagram showing the surface roughness of a polishing pad in Comparative Example 2. FIG. 6 is a diagram showing the surface roughness of a polishing pad in Comparative Example 3. FIG.

Hereinafter, although an embodiment is described about the present invention, the present invention is not limited to this.
Conventionally, when a hard dresser such as a diamond dresser is used in dressing a polishing pad, the wear amount of the polishing pad is too large, so that a large amount of particles are generated or the life of the polishing pad is extremely shortened. There was a problem.

  In order to solve this problem, the present inventors have studied in order to realize a dressing capable of appropriately roughening the polishing surface of the polishing pad and suppressing the abrasion of the polishing pad. Then, with the tip of the brush protruding from the dressing surface of the plate, if the tip of the brush and the dressing surface of the plate are simultaneously pressed against the polishing pad and brought into sliding contact with the polishing pad, the polishing surface of the polishing pad is appropriately roughened and the polishing pad It was found that the amount of wear can be suppressed, and the present invention was completed.

Hereinafter, the dressing apparatus of the present invention will be described. First, a dressing apparatus of the present invention for dressing a polishing pad of a double-side polishing apparatus as described below will be described as a first aspect.
As shown in FIG. 1, the double-side polishing apparatus 1 includes an upper surface plate 2 and a lower surface plate 3 provided opposite to each other, and the upper and lower surface plates 2 and 3 are respectively provided with polishing pads 4 and 4 ′. Is affixed. The carrier 5 is provided with a holding hole 6 for holding a wafer (for example, a silicon wafer), and the carrier 5 is sandwiched between the upper and lower surface plates 2 and 3. The upper and lower surface plates 2 and 3 are rotated by upper and lower rotary shafts 7 and 8, respectively.

  When dressing the polishing surface of the polishing pads 4, 4 ′, the dressing device 10 of the present invention is disposed between the upper surface plate 2 and the lower surface plate 3 as shown in FIG. 1. The dressing apparatus 10 has dress surfaces on the upper and lower sides, and dresses by pressing these dress surfaces against the upper and lower polishing pads while rotating the upper and lower surface plates 2 and 3.

  As shown in FIG. 2, the dressing device 10 includes a plurality of brushes 11 and a plate 13 below the rigid plate 12. The plate 13 and the rigid plate 12 may be a single body, and the whole may be a plate. The brush 11 is disposed below the rigid plate 12 via the spacer 14. For example, a nylon brush can be used as the brush 11. Here, in the dressing apparatus 10 of the present invention, the tip of the brush 11 protrudes from the dress surface that is in sliding contact with the polishing pad 4 of the plate 13. The length of the tip of the brush 11 protruding from the dress surface of the plate 13 can be adjusted by a spacer 14 interposed between the rigid plate 12 and the brush 11, for example. As shown in FIG. 4, the dressing device 10 may be formed in a disk shape.

  Moreover, as shown in FIG. 2A and FIG. 4A, the position where the brush 11 is disposed can be inside the plate 13, or the position of the brush 11 in FIG. As shown in B), it may be outside the plate 13. As shown in FIGS. 2B and 4B, when the surface area of the plate 13 is large, the grooves 15 can be introduced into the surface.

  The dressing device 10 shown in FIG. 1 has two brushes 11, rigid plates 12, and plates 13 each. The two rigid plates 12 are attached to the top and bottom of the arm 9, respectively. 2 and 4, the brush 11 is disposed on the surface of the rigid plate 12 opposite to the polishing cloth 4, 4 ′ via the spacer 14 so as to be adjacent to the spacer 14. A plate 13 is arranged. Further, the arm 9 shown in FIG. 1 can linearly reciprocate back and forth and from side to side, whereby the dressing device 10 can linearly reciprocate back and forth and left and right. When dressing the polishing pads 4 and 4 ′, the arm 9 is displaced in the vertical direction so that the tip of the brush 11 and the plate 13 are simultaneously pressed against the polishing pads 4 and 4 ′. The dressing device 10 pressed against is moved back and forth linearly and slidably contacted to perform dressing of the polishing pads 4 and 4 '.

With such a dressing device 10, the tip of the brush 11 protruding from the dress surface of the plate 13 can be cut in a direction perpendicular to the polishing surface of the polishing pads 4, 4 ′. Moreover, since the surface is roughened using the soft brush 11, abrasion of the polishing pads 4, 4 ′ can be suppressed. As a result, the generation of particles from the polishing pads 4 and 4 ′ can be suppressed and the life of the polishing pads 4 and 4 ′ can be improved while moderately roughening the polishing surface of the polishing pad.
At this time, if the tip of the brush 11 and the plate 13 are simultaneously pressed against the polishing pads 4, 4 ′, the plate 13 directly contacts the polishing pads 4, 4 ′, so that the tip of the brush 11 is brought into contact with the polishing pads 4, 4 ′. The pressure applied to 'can be easily adjusted. Furthermore, since the dressing capacity of the dressing device 10 can be adjusted by adjusting the length of the tip of the brush 11 protruding from the dress surface and the wire diameter of the brush used, the dressing according to the polishing pad to be used can be performed. Become. By adjusting the dressing ability, it becomes possible to finely dress the entire polishing surface of the polishing pad 4, 4 ', and the entire polishing surface of the polishing pad 4, 4' is roughened while suppressing the generation of particles. Will be able to.

At this time, it is preferable that the length at which the tip of the brush 11 protrudes from the dress surface is 1 mm or less.
If it is such, the front-end | tip of the brush 11 can cut more reliably in the direction perpendicular | vertical with respect to the polishing surface of polishing pad 4, 4 '. As a result, it is possible to reliably roughen the polishing surface of the polishing pad while suppressing generation of particles from the polishing pad.

At this time, the brush 11 is preferably made of synthetic fiber nylon, and the material of the plate 13 can prevent the wafer from being contaminated with metal. Since conventional diamond dressers are often made by electrodepositing diamond abrasive grains onto a metal plate and fixing them, metal can be eluted from the metal plate and electrodeposition means in an alkaline environment when polishing the wafer. To do. In order to suppress metal elution, the metal portion may be protected with a resin. However, metal elution may occur due to wear or scratches on the resin, so that metal contamination cannot be prevented.
However, if the material does not contaminate the metal, the metal impurities are not eluted from the brush 11 and the plate 13, and therefore the contamination of the polishing pad can be prevented.

Furthermore, the material of the plate may be made of ceramics or DLC (diamond-like carbon). This ceramic can be alumina ceramic, for example.
A plate made of such a material is excellent in chemical resistance and wear resistance, and therefore can suppress impurity contamination and particle generation from the plate.

Next, the dressing apparatus of the present invention for dressing the polishing pad of the single-side polishing apparatus will be described as a second aspect.
As shown in FIG. 3, the single-side polishing apparatus 1 ′ has a surface plate 16 on which the polishing pad 4 is attached and a polishing head 17. In such a polishing apparatus 1 ′, first, the silicon wafer is held by the polishing head 17. Subsequently, the surface plate 16 and the polishing head 17 are rotated while supplying the polishing agent onto the polishing pad 4 from the polishing agent supply mechanism (not shown), for example, the surface of the silicon wafer is brought into sliding contact with the polishing pad 4. To polish.

When dressing the polishing pad 4, a dressing apparatus 10 ′ is disposed on the polishing pad 4 as shown in FIG. 3. The dressing apparatus 10 ′ has a dress surface on the lower side, and performs dressing by pressing the dress surface against the polishing pad 4.
Furthermore, the dressing apparatus 10 ′ has an arm 9 ′, a rotation mechanism 18, and a pivot shaft 19. The turning shaft 19 is connected to the rotation mechanism 18 via the arm 9 ′. The swivel shaft 19 can be displaced in the vertical direction, and by this displacement, the force for pressing the dress surface of the dressing device 10 ′ against the polishing pad 4 can be controlled. Further, by rotating the turning shaft 19, the dressing device 10 ′ can be turned and reciprocated around the turning shaft 19.

  As shown in FIG. 4, there is no particular limitation, but the dressing device 10 'can be disk-shaped. The dressing apparatus 10 ′ includes a plurality of brushes 11 and a disk-like (FIG. 4B) or annular (FIG. 4A) plate 13 ′ below a disc-like rigid plate 12 ′. The brush 11 is disposed below the rigid plate 12 ′ via a disc-like (FIG. 4A) or annular (FIG. 4B) spacer 14 ′. Here, in the dressing apparatus 10 ′ of the present invention, the tip of the brush 11 protrudes from the dress surface in sliding contact with the polishing pad 4 of the plate 13 ′. The length of the tip of the brush 11 protruding from the dress surface of the plate 13 ′ can be adjusted by a spacer 14 ′ interposed between the rigid plate 12 ′ and the brush 11. The wire diameter of the brush 11 to be used can also be adjusted as described above.

Further, the position where the brush 11 ′ is arranged can be inside the plate 13 ′ as shown in FIG. 4A, or can be outside as shown in FIG. 4B. it can. As shown in FIG. 4B, when the surface area of the plate 13 ′ is large, a groove 15 ′ can be introduced into the surface.
If this is the case, the generation of particles from the polishing pad 4 can be suppressed and the life of the polishing pad 4 can be improved while the polishing surface of the polishing pad is moderately roughened as in the first embodiment. It becomes.

Next, the dressing method of the present invention will be described. Here, the case where the dressing apparatus 10 of the present invention is used in the polishing apparatus 1 as shown in FIG. 1 will be described.
First, the dressing device 10 is disposed between the upper surface plate 2 and the lower surface plate 3 so that the tips of the upper and lower brushes 11 face the polishing pads 4 and 4 ′. The tip of the brush 11 of the dressing device 10 is projected from the dress surface of the plate 13. Next, the dressing apparatus 10 is pressed against the polishing pads 4, 4 ′ by pushing down the upper surface plate 2. Next, the dressing apparatus 10 is linearly reciprocated back and forth and left and right by the arm 9 while rotating the upper and lower surface plates 2 and 3 respectively. In this way, the tip of the brush 11 and the plate 13 are simultaneously pressed against the polishing pads 4 and 4 ′ and brought into sliding contact with each other to perform dressing.

  In this way, the tip of the brush 11 protruding from the dress surface of the plate 13 can be cut in a direction perpendicular to the polishing surface of the polishing pads 4, 4 ′. Further, since the polishing surface is roughened using the brush 11, the abrasion of the polishing pads 4, 4 'can be suppressed. As a result, generation of particles from the polishing pads 4 and 4 ′ can be suppressed and life can be improved while moderately roughening the polishing surface of the polishing pad. Furthermore, the dressing capacity of the dressing device 10 can be adjusted by adjusting the length of the tip of the brush 11 protruding from the dressing surface and the wire diameter of the brush to be used, so that dressing according to the polishing pad to be used can be performed. By adjusting the dressing ability, it becomes possible to finely dress the entire polishing surface of the polishing pad 4, 4 ', and the entire polishing surface of the polishing pad 4, 4' is roughened while suppressing the generation of particles. Can do.

At this time, it is preferable that the length at which the tip of the brush 11 protrudes from the dress surface is 1 mm or less.
In this way, the tip of the brush can be cut into the polishing pad more reliably. As a result, the polishing surface of the polishing pad can be reliably roughened while suppressing the generation of particles from the polishing pad.

At this time, the brush 11 is preferably made of synthetic fiber nylon, and the plate 13 can be made of a material that does not contaminate the wafer with metal.
In this way, if a material that does not contaminate the metal is used as the material of the brush 11 and the plate 13, a wafer with higher cleanliness can be obtained.

Further, as the material of the plate, a material made of ceramics or DLC (diamond-like carbon) can be used.
If a plate made of such a material is used, it is a material excellent in chemical resistance and wear resistance, so that impurity contamination and generation of particles from the plate can be suppressed.

  Moreover, if the dressing method and dressing apparatus of the present invention are used for dressing a polishing pad of a polishing apparatus that circulates and repeatedly uses an abrasive, it is possible to prevent the abrasive used repeatedly from being contaminated with particles or metal. Further, contamination of the polishing pad and the wafer can be further suppressed.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples of the present invention, but the present invention is not limited to these.

(Example)
In the single-side polishing apparatus 1 ′ as shown in FIG. 3, dressing of the polishing pad was performed between polishing batches using the dressing apparatus 10 ′ of the present invention shown in FIG. 4B according to the dressing method of the present invention. . At this time, a nylon brush having a diameter of 4 mm, a wire diameter of 0.1 to 0.2 mm, and 12 × 2 rows was used as the brush. A plate having a diameter of 80 mm and an alumina ceramic material was used. The plate was processed so that two grooves having a width of 2 mm and a depth of 2 mm were orthogonal to each other. The abrasive was prepared by diluting and adjusting the stock solution to the required magnification, and was drained without being recycled after being supplied onto the surface plate during polishing.

  Further, as shown in Table 1, the length at which the tip of the brush protrudes from the dress surface of the plate was 1.0 mm, the initial dressing was not performed, and the inter-batch dressing time was 14.0 seconds. Then, when the wafer polishing time reached 60 hours, the entire polishing batch was finished, and dressing was performed.

  In this example, the flatness level of the outermost peripheral portion of the polished wafer and the number of particles having a particle size of 100 nm or less attached to the polished wafer surface were measured. Regarding the number of particles measured, a relative number was calculated with respect to the number of particles in Comparative Example 2, which is a case where a ceramic dresser with a small amount of wear on the polishing pad was used. Further, after completion of the entire polishing batch, the roughness of the polishing pad surface and the wear amount of the polishing pad were measured. The abrasion amount of the polishing pad was measured using a polishing pad in which a groove was previously formed on the polishing surface, and the groove depth after polishing was measured with a laser displacement meter. And the relative groove depth when the depth of the groove | channel at the time of unused before a grinding | polishing start was made into 100% was computed. It can be said that the greater the relative groove depth, the smaller the wear amount.

The measurement result of the flatness level is shown in FIG. As shown in FIG. 5, the flatness level of the polished wafer was equivalent to Comparative Example 1 using a diamond dresser described later. The measurement result of the amount of particles is shown in FIG. As shown in FIG. 6, the amount of particles was almost the same as when a ceramic dresser with a small amount of wear on the polishing pad was used. The measurement result of the roughness of the polishing pad surface is shown in FIG. The horizontal axis of the graph of FIG. 7 represents the displacement from the average height of the polished surface, and the vertical axis represents the ratio of the distribution of the displacement. As shown in FIG. 7, as for the surface roughness of the polishing pad, there are many cases where the displacement from the average height of the polishing pad surface is large, and the polishing pad surface is roughened to the same extent as in Comparative Example 1 using a diamond dresser. I was able to. As shown in FIG. 8, the abrasion amount of the polishing pad was significantly reduced as compared with Comparative Example 1.
As described above, when a polishing pad is dressed using the dressing apparatus and the dressing method of the present invention, the surface of the polishing pad can be roughened in the same manner as a diamond dresser. Furthermore, since the amount of wear on the surface of the polishing pad is less than when a diamond dresser is used, it has been found that the generation of particles can be suppressed and the life of the polishing pad can be improved.

(Comparative Example 1)
In place of the dressing apparatus of the present invention, dressing was performed under the same conditions as in the example except that a conventional diamond dresser was used and the initial dressing time and the inter-batch dressing time were changed. The flatness level of the wafer polished by the method, the number of particles adhering to the wafer surface, the roughness of the polishing pad surface, and the wear amount of the polishing pad were evaluated.
The initial dressing time, the batch-to-batch dressing time, and the pressing amount were dressed as four values of Evaluation 1 to Evaluation 4 in Table 2 below. The pressing amount in Table 2 is the displacement in the direction perpendicular to the surface of the polishing pad from the position where the diamond dresser first contacts the polishing pad.

As a result, as shown in FIG. 5, the flatness level of the polished wafer was good. FIG. 9 is a measurement result of the number of particles adhering to the wafer polished under the conditions of Evaluation 1 to Evaluation 4. The number of particles thus measured was calculated as a relative number with respect to the number of particles in Comparative Example 2 in which a ceramic dresser was used as in Example 1. As shown in FIG. 9, the number of particles significantly increased compared to the relative number of particles in the example (FIG. 6). The measurement result of the roughness of the polishing pad surface is shown in FIG. The horizontal axis of the graph of FIG. 10 represents the displacement from the average height of the polished surface, and the vertical axis represents the ratio of the distribution of the displacement. As shown in FIG. 10, the surface of the polishing pad was sufficiently roughened. As shown in FIG. 8, it was found that the wear amount of the polishing pad was much larger than that of the example, and the life of the polishing pad was shortened.
As described above, when the dressing is performed using the diamond dresser, the surface of the polishing pad is roughened. However, since the amount of wear on the surface of the polishing pad is too large compared to the example, excessive particles are generated, and further, the polishing pad. It turns out that the life of will be shortened.

(Comparative Example 2)
Instead of using the dressing apparatus of the present invention, a wafer which is dressed under the same conditions as in the embodiment and polished in the same manner as in the embodiment except that a dressing apparatus for dressing a polishing pad with a ceramic plate without a brush is used. The flatness level, the number of particles adhering to the wafer surface, the roughness of the polishing pad surface, and the wear amount of the polishing pad were evaluated.
As a result, as shown in FIG. 5, it was found that the flatness level of the polished wafer was inferior to that of the example. The amount of generated particles was almost the same as the example (FIG. 6). The horizontal axis of the graph of FIG. 11 represents the displacement from the average height of the polished surface, and the vertical axis represents the ratio of the distribution of the displacement. As shown in FIG. 11, the surface of the polishing pad could hardly be roughened. Regarding the wear amount of the polishing pad, as shown in FIG. 8, there was no wear of the polishing pad.
From the above, it was found that when the polishing pad was dressed with a ceramic plate without a brush, the polishing pad surface could not be roughened, so that the polishing ability of the polishing pad was low and the flatness level of the polished wafer deteriorated.

(Comparative Example 3)
Instead of using the dressing apparatus of the present invention, a dressing apparatus for dressing a polishing pad with only a nylon brush is used. The roughness level, the number of particles adhering to the wafer surface, the roughness of the polishing pad surface, and the wear amount of the polishing pad were evaluated.
As a result, it was found that the flatness level of the polished wafer was inferior to that of the example. The amount of generated particles was almost the same as that of the example. As shown in FIG. 12, the surface of the polishing pad could hardly be roughened. About the abrasion amount of the polishing pad, as shown in FIG. 8, the abrasion of the polishing pad was hardly seen.
From the above results, it was found that when the polishing pad was dressed only with a nylon brush, the surface of the polishing pad could not be roughened, so that the polishing ability of the polishing pad was low and the flatness level of the polished wafer deteriorated.

  From the results of Examples and Comparative Examples 1-3, in order to moderately roughen the polishing pad and suppress the generation of particles from the polishing pad and the shortening of the life of the polishing pad, the tip of the brush protrudes from the dress surface of the plate. As a result, it was confirmed that it was necessary to dress the polishing pad.

  The present invention is not limited to the above embodiment. The above-described embodiment is an exemplification, and the present invention has any configuration that has substantially the same configuration as the technical idea described in the claims of the present invention and that exhibits the same effects. Are included in the technical scope.

DESCRIPTION OF SYMBOLS 1 ... Double-side polish apparatus, 1 '... Single-side polish apparatus, 2 ... Upper surface plate, 3 ... Lower surface plate,
4, 4 '... polishing pad, 5 ... carrier, 6 ... holding hole,
7 ... Upper rotation shaft, 8 ... Lower rotation shaft, 9, 9 '... Arm,
10, 10 '... dressing device, 11 ... brush, 12, 12' ... rigid plate,
13, 13 '... plate, 14, 14' ... spacer, 15, 15 '... groove,
16 ... Surface plate, 17 ... Polishing head, 18 ... Rotating mechanism, 19 ... Swivel axis.

Claims (8)

A dressing method for dressing a polishing pad by pressing and sliding a brush and a plate against a polishing pad for polishing a wafer attached on a surface plate,
The tip of the brush is protruded from a dress surface that is in sliding contact with the polishing pad of the plate, and then the tip of the brush and the plate are simultaneously pressed and brought into sliding contact with the polishing pad to dress the polishing pad. And dressing method.   The dressing method according to claim 1, wherein a length of a tip of the brush protruding from the dress surface is 1 mm or less.   The dressing method according to claim 1 or 2, wherein a material not contaminated with metal is used as a material of the brush and the plate.   The dressing method according to claim 1 or 2, wherein a material made of ceramics or DLC (diamond-like carbon) is used as a material of the plate. A dressing device for dressing a polishing pad for polishing a wafer affixed on a surface plate, comprising a brush and a plate, and polishing by pressing the brush and the plate against the polishing pad and slidingly contacting each other Dressing pads,
The tip of the brush protrudes from the dress surface that is in sliding contact with the polishing pad of the plate, and the tip of the brush and the plate are simultaneously pressed against the polishing pad to slide and dress the polishing pad. A dressing device characterized by.   6. The dressing apparatus according to claim 5, wherein a length of a tip of the brush protruding from the dress surface is 1 mm or less.   The dressing apparatus according to claim 5 or 6, wherein a material of the brush and the plate is not contaminated with metal.   The dressing device according to claim 5 or 6, wherein a material of the plate is made of ceramics or DLC (diamond-like carbon).

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