JP2010274352A - Dresser for abrasive cloth - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a dresser excellent in grinding performance of a pad surface by controlling a direction of individual diamond abrasive grains brazed to a metallic supporting member. <P>SOLUTION: In the dresser for the abrasive cloth, a plurality of abrasive grains are fixed, in a single layer, onto the surface of the metallic supporting member. Each of the abrasive grains is a single crystal abrasive grain having a plurality of crystal habit surfaces, and out of the number of the fixed abrasive grains, the number of the abrasive grains wherein one of the crystal habit surfaces is arranged almost in parallel to the surface of the supporting member, is 80% or more. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention provides a dresser used for maintaining the flatness of the polishing cloth and for removing clogging and foreign matters in a chemical and mechanical planar polishing (CMP) process. About.

  A device for polishing the surface of a semiconductor wafer, a device for flattening the surface of a wiring or an insulating layer in the course of manufacturing an integrated circuit, a device for flattening the surface of an Al plate or glass plate used for a magnetic hard disk substrate, Etc., CMP polishing is used. CMP polishing is, for example, a method of flattening a surface to be polished by pressing the surface to be polished while supplying a slurry liquid containing fine abrasive grains to a rotating substrate to which a urethane polishing pad is attached. It is. As a matter of course, the polishing ability of this polishing pad decreases with the use time, but in order to suppress this decrease, the polishing pad surface layer is ground at regular intervals to maintain the flatness of the polishing pad. , I am always dressing so that a new surface comes out. A part used for this dressing is called a dresser, and abrasive grains are joined to a metal substrate by electrodeposition or brazing.

  Recently, in addition to the conventional requirement to eliminate scratches due to a decrease in the depth of focus of a pattern exposure apparatus due to the extremely narrow line / space of an integrated circuit or an increase in the recording capacity of a magnetic hard disk. There is an increasing demand for flatness, such as reducing the waviness of the surface to be polished. In order to meet these demands, it is necessary to uniformly grind the pad surface by dressing to maintain pad flatness, and pad grinding force to remove clogging and foreign matters of the pad is also necessary Become. In addition, the pad grinding force usually decreases with dressing time. However, it is practically important to stabilize the CMP process to suppress the grinding force reduction as much as possible and to extend the dresser life. .

  The following are disclosed as dressers for the purpose of uniform pad grinding. Patent Document 1 discloses a pad conditioner having a superabrasive layer in which a superabrasive grain is fixed to the surface of a disk-shaped base metal, and a plurality of regions are provided in the abrasive layer. Discloses a dresser in which superabrasive grains are arranged in an equilateral triangle, and the abrasive grain spacing in the region on the outer peripheral side is smaller than the central axis side of the disk-shaped base metal. Patent Document 2 is a dresser in which an abrasive layer is electrodeposited on one surface of a disk-shaped base material, and the center interval between adjacent abrasive grains is 2 to 10 times the average grain size of the abrasive grains. Patent Document 3 discloses a dresser in which a superabrasive surface having a blunt edge is provided on the inner peripheral side of an end surface in contact with the polishing pad surface, and a superabrasive surface having a sharp edge on the outer peripheral side is provided. Has been.

JP 2006-55944 A JP 2001-121418 A JP 2001-113456 A

  As described above, although dressers intended to uniformly grind the pad surface have been reported conventionally, these are two-dimensional arrangements of abrasive grains, ones with changed abrasive grain intervals, or It uses a plurality of abrasive grains having different abrasive grain edge shapes, and does not focus on the direction of each abrasive grain. In particular, when fixing diamond abrasive grains by brazing, the abrasive grains fluctuate in the molten brazing material, and the direction of the abrasive grains changes. unknown.

  An object of the present invention is to provide a dresser having excellent grinding performance on a pad surface by controlling the direction of individual diamond abrasive grains, particularly in a dresser in which diamond abrasive grains are brazed to a metal support. And

The gist of the present invention is as follows.
(1) A dresser for a polishing cloth in which a plurality of abrasive grains are fixed to a single layer on the surface of a metal support material, each of the abrasive grains being a single crystal abrasive grain having a plurality of crystal habit planes, Of the total number of the fixed abrasive grains, the number of abrasive grains in which one of the plurality of crystal habit planes is arranged substantially parallel to the surface of the support material is 80% or more. A dresser for polishing cloth characterized by
(2) The dresser for polishing cloth according to the above item (1), wherein an average particle diameter of the abrasive grains is 5 μm or more and 300 μm or less.
(3) The dresser for abrasive cloth as described in (1) or (2) above, wherein the abrasive grains are brazed to the surface of the metal support material.
(4) The dresser for polishing cloth according to any one of (1) to (3) above, wherein the abrasive grains are diamond abrasive grains.
(5) The dresser for polishing cloth according to any one of (1) to (4), wherein the metal support is made of stainless steel.

  By using the dresser of the present invention, the pad grinding force of individual single crystal abrasive grains (preferably diamond abrasive grains) becomes substantially uniform, so that sufficient pad grinding force is maintained and excellent pad flatness is achieved. Securement is also possible. Furthermore, since the contact of the individual abrasive grains with the pad is made uniform, the effect of extending the life of the dresser is exhibited. Of course, when single crystal abrasive grains are brazed, a feature of suppressing the falling of abrasive grains is also obtained. For this reason, if the dresser of the present invention is applied to a CMP polishing pad conditioner, the flatness of the product substrate is improved and excellent quality is achieved, and high productivity can be maintained.

It is a figure which shows the example of the manufacturing method of the dresser of this invention.

  Pad flatness is particularly important in CMP polishing of semiconductor integrated circuits or in CMP polishing of Al or glass magnetic hard disk substrates. Depending on the area of one dresser surface, usually several thousand to several tens of thousands of single crystal abrasive grains (for example, diamond abrasive grains, preferably artificial diamond abrasive grains) are fixed. However, since the pad grinding force for each single crystal abrasive grain differs greatly, it has not been easy to maintain the pad flatness efficiently. The present inventors paid attention to the shape of single crystal abrasive grains used as abrasive grains. For example, if one crystal habit plane of a single crystal diamond abrasive grain having a substantially square octahedron shape abuts substantially parallel to the pad surface to be ground, a sharp edge portion constituting the periphery of one crystal habit plane Assuming that the pad can be ground efficiently, and as a result of verification, the present invention has been completed.

  As described above, in order for the pad surface and the crystal habit plane of the single crystal abrasive grains (preferably diamond abrasive grains) to contact substantially in parallel, one crystal habit plane of the single crystal abrasive grains is attached to the metal support material. What is necessary is just to arrange | position substantially parallel to the surface. By disposing the single crystal abrasive grains in this way, the pad surface is efficiently ground by the sharp edges that form the periphery of one crystal habit plane of the single crystal abrasive grains. If the number of single crystal abrasive grains arranged in this way is 80% or more with respect to the total number of abrasive grains fixed on the entire dresser surface, the effect of the present invention is exhibited.

  The average grain size of the single crystal abrasive grains may be 5 μm or more and 300 μm or less. The size of the abrasive grains depends on the object to be polished by CMP, but in the case of CMP polishing of a semiconductor integrated circuit, relatively large single crystal abrasive grains (preferably diamond abrasive grains) are used; In the case of CMP polishing of a magnetic hard disk substrate, relatively small single crystal abrasive grains (preferably diamond abrasive grains) are used. When the particle size is less than 5 μm, it is not easy to arrange one crystal habit plane of the single crystal abrasive grains substantially parallel to the surface of the metal support material. When the particle size exceeds 300 μm, the unevenness of the polished pad becomes large, and the flatness of the pad tends to deteriorate. Furthermore, a particle diameter of 10 μm or more and 200 μm or less is more preferable from the viewpoint of ease of manufacturing a dresser and pad flatness.

  The average particle diameter of the single crystal abrasive grains can be measured according to JIS B 4130. However, if the average particle size becomes small, it may not be measured by JIS B 4130. In that case, the measurement may be performed as follows. Single crystal abrasive grains are directly observed with an SEM to measure individual grain sizes. The average value of about 100 single crystal abrasive grains is defined as the average grain size. When measuring individual particle diameters, the average particle diameter can be efficiently obtained by processing a photograph taken with an SEM using commercially available image processing software.

  In the dresser of the present invention, the single crystal abrasive grains are arranged in a single layer on the support surface. The dresser of the present invention is characterized by the arrangement of individual single crystal abrasive grains and the method of brazing the single crystal abrasive grains to a metal support.

  An example of the dresser manufacturing process of the present invention will be described with reference to FIG. As shown in FIG. 1, first, a foil-like brazing material 1 is temporarily fixed on a metal support material 2 by spot welding or the like. Thereafter, the brazing material 1 may be melted and alloyed with the surface of the metal support material 2 to be joined, or may be temporarily fixed. On the other hand, when using a powder brazing material, after the diamond abrasive grains are uniformly dispersed on the metal support material, the brazing material is melted and alloyed with the surface of the metal support material (step 1). ).

  Next, single crystal abrasive grains 3 (for example, substantially tetrahedral octahedral diamond abrasive grains) are arranged in a single layer on the flat plate 4, and light vibration is applied to the flat plate 4. Then, one crystal habit plane of the single crystal abrasive grain 3 is in close contact with the surface of the flat plate and becomes parallel. Due to this light vibration, the crystal habit plane having a larger area is in close contact with the flat plate, so that the wobbling of the single crystal abrasive grains 3 is reduced and the arrangement is more stable (step 2).

  On the flat plate 4 on which the single crystal abrasive grains 3 are arranged, the metal support material 2 is placed with the surface with the brazing material 1 facing downward, and the brazing material 1 and the single crystal abrasive The grain 3 is brought into contact (step 3). In this state, it is inserted into a heat treatment furnace, and the single crystal abrasive grains 3 and the metal support material 2 are brazed (step 4). The brazing heat treatment may be performed with the upper and lower surfaces reversed. The flat plate 4 can be removed from the single crystal abrasive grains 3 to obtain the dresser of the present invention (step 5).

  In the dresser manufactured by this manufacturing method, one crystal habit plane of single crystal abrasive grains is in close contact with the surface of the metal support material through a brazing material having a uniform thickness. Therefore, the brazing feature of suppressing the falling of abrasive grains is obtained. Furthermore, since the pad grinding force of each single crystal abrasive grain becomes substantially uniform, a sufficient pad grinding force can be maintained and excellent pad flatness can be ensured. Furthermore, the height of the single crystal abrasive grains becomes substantially uniform, and the individual single crystal abrasive grains come into contact with the pad uniformly. As a result, the load (weight) applied to each single crystal abrasive grain is reduced, the abrasive wear is reduced, and the effect of extending the dresser life is exhibited.

  The thickness of the brazing material is preferably 0.4d to 0.6d, where d is the size of the diamond abrasive grains. If it is less than 0.4d, the degree of burying of the diamond abrasive grains in the brazing material is lowered, and there is a concern that the holding power of the diamond abrasive grains is reduced. In the case of more than 0.6d, the sharp edge portion constituting the periphery of the crystal habit surface of the single crystal abrasive grain may be covered with the brazing material, and the pad grinding force is reduced. When a powder brazing material is used, it is preferable that the thickness of the brazing material when re-solidified after melting is 0.4d to 0.6d.

  The flat plate is preferably a ceramic plate that does not cause an alloying reaction with the brazing material, and is preferably alumina, zirconia, silicon nitride, or the like. If these surfaces are mirror-finished after machining, a flat plate can be easily formed.

  The temperature for brazing the single crystal abrasive grains is Tm ° C. to (Tm + 20) ° C. when the melting point of the brazing material is Tm ° C. This is because if the temperature is raised above (Tm + 20) ° C., the surface tension of the brazing material decreases, and the brazing material tends to sag from the metal support material to the flat plate side. Even when brazing in the state where the upper and lower surfaces of Step 3 in FIG. 1 are inverted, if the temperature is raised above (Tm + 20) ° C., there is a portion where the molten brazing material and the flat plate come into contact with each other. Since it occurs, it is not preferable. The time for maintaining the temperature at Tm ° C to (Tm + 20) ° C is preferably 5 minutes or more and 20 minutes or less. If it is less than 5 minutes, the alloying reaction between the single crystal abrasive grains and the brazing material is insufficient, and the holding power of the single crystal abrasive grains tends to decrease. On the other hand, holding for over 20 minutes does not affect the brazed state.

  The arrangement pattern of the single crystal abrasive grains may be random or regular. In the case of regular arrangement, single crystal abrasive grains may be arranged at each vertex of a matrix such as a triangle, a quadrangle, a pentagon, and a hexagon. Moreover, it is possible to arrange abrasive grains in various pattern areas. If a sieve or the like having an opening at a predetermined position is arranged on the flat plate and the abrasive grains are dropped into the flat plate through the opening of the sieve, the single crystal abrasive grains can be arranged according to a predetermined rule. As described above, when a light vibration is applied to the flat plate, it is preferably performed with the sieve placed.

  Diamond abrasive grains may be brazed while the sieve is placed on the flat plate. However, in this case, it is preferable to use a sieve in which a predetermined position of the organic material foil is opened. This is because the sieve itself is decomposed and volatilized while raising the temperature to the brazing temperature.

  The metal support material is preferably stainless steel having low reactivity with acidic or alkaline slurry. Typical stainless steels such as SUS304, SUS316, and SUS430 are suitable. The surface of general structural steel such as carbon steel plated with Ni or the like can also be used. In addition, the shape of the metal support material is not particularly specified, and may be a polygonal shape such as an octagon or an icosahedron, but the metal support material itself grinds the pad while rotating, so uniform grinding In order to ensure the property, a disk shape is preferable.

As the brazing material, a Ni—Cr—Fe—Si— system, a Ni—Si—B system, or a Ni—Cr—Si—B system represented by JIS standard materials such as Bni-2 and Bni-5 can be applied. When the brazing material is a foil, it can be temporarily attached by spot welding. In the case of powder, for example, a kneaded cellulose-based binder or the like may be applied to a metal support material. Brazing heat treatment, after evacuated to about 10 -3 ^Pa, the temperature is raised to a predetermined temperature. Most of the binder is vaporized during the temperature rise.

  The single crystal abrasive grains for grinding the dresser of the present invention are not limited to diamond abrasive grains, but may be single crystal grains (cubic boron nitride, boron carbide, silicon carbide, and aluminum oxide) having grinding ability. Good.

  Hereinafter, based on an Example, this invention is demonstrated in detail.

[Example 1]
A dresser was produced using single crystal artificial diamond abrasive grains having an average particle diameter d of 150 μm, and pad grinding rate (grinding speed) and pad flatness were evaluated.

  The metal support used was a disc-shaped SUS304 stainless steel having a diameter of 100 mm and a thickness of 4 mm, and the surface was machined flat. The diamond abrasive grains arranged on the surface of the metallic support were patterned so as to be located at each vertex of the square matrix, and the distance between the diamond abrasive grains was 0.4 mm. Specifically, diamond abrasive grains were arranged in a ring-shaped region between a circle with a radius of 25 mm and a circle with a radius of 48 mm drawn on one surface of the metal support material. More specifically, this ring-shaped region is divided into four arc-shaped regions at an equal angle (90 °), and diamond abrasive grains are arranged in the gap (2 mm width) between adjacent arc-shaped regions. There wasn't. In each arc-shaped region, diamond abrasive grains were regularly arranged so as to be located at each vertex of the square matrix.

  The specific arrangement procedure of the diamond abrasive grains was as follows. First, a foil-like brazing material was temporarily attached by spot welding to a region of a stainless steel support material where diamond abrasive grains are arranged. The foil-like brazing material had a JIS standard Bni-2 composition, and two foils each having a thickness of 40 μm were used. The measured melting point of the brazing material used was 1000 ° C. The support material on which the brazing material was spot-welded was subjected to heat treatment at 1000 ° C. for 5 minutes in a vacuum. After the brazing material was once melted on the support material, it was further solidified to integrate both.

  As the flat plate, an alumina plate having a thickness of 5 mm and a side of 120 mm was used. The surface of the flat plate was mirror-polished using a lapping machine.

  Next, a sieve was prepared in which holes enough to pass through the diamond abrasive grains were arranged at each vertex of the square matrix. The material of the sieve was an organic material used for normal screen printing, and the thickness of the sieve was about 120 μm. Using known photolithography and etching, a circular opening having a diameter of 170 μm is formed in an organic film so as to be arranged at each vertex of the square matrix, and the distance between the openings is 0.4 mm. It was. An opening is provided in a ring-shaped region sandwiched between a circle having a radius of 25 mm and a concentric circle having a radius of 48 mm in an organic material film; and the ring-shaped region is divided into four arc-shaped regions at an equal angle (90 °); No opening was provided in the gap (2 mm width) between adjacent arc-shaped regions.

  The prepared sieve was placed on a flat plate, and diamond abrasive grains were arranged through the sieve. The end of the sieve placed in close contact with the flat plate was fixed with a tape to suppress deviation. Diamond abrasive grains were sprayed from the top of the sieve, and diamond abrasive grains were dropped through the individual openings. Excess diamond abrasive on the sieve was removed with a brush. Thereafter, the inside of the opening was observed using a stereomicroscope. As a result of observation, it was confirmed that one diamond abrasive grain was contained in one opening. In this state, the flat plate was placed on the ultrasonic vibration plate to give light vibration. Due to this vibration, the diamond abrasive grains that had been suspended from the inner wall of the opening of the sieve were grounded to the surface of the flat plate. As a result, one crystal habit plane of the diamond abrasive grains adhered to the flat plate surface.

  Cover the support with the brazing material facing down on the flat plate on which the diamond abrasive grains are regularly arranged, and contact the brazing material of the support with the diamond abrasive on the flat plate. I let you. It inserted in the vacuum heating furnace in this state, and the brazing process for 10 minutes was performed at 1010 degreeC. The organic material sieve decomposed and disappeared by about 500 ° C. during the temperature increase. After the brazing treatment, the flat plate and diamond abrasive grains could be easily separated.

  Ten sheets of the dresser of the present invention were manufactured by such a manufacturing method. An observation site of 10 mm × 10 mm is set in the vicinity of the center of each arc-shaped region of one dresser, and the crystal habit planes of all diamond abrasive grains in the observation site are supported using a laser microscope. The parallelism to the material surface was evaluated. Specifically, the dresser support was placed on a measuring table of a measuring instrument, and the shape profile of each diamond abrasive grain was determined. The height from the support surface of the edge constituting the periphery of one crystal habit plane of the diamond abrasive grains was determined. When the maximum difference in height from the support surface of each edge (maximum-minimum) was within 3 μm, it was evaluated that one crystal habit plane of the diamond abrasive grain was substantially parallel to the support material. With respect to one dresser, all diamond abrasive grains included in the observation site near the center of the four arc-shaped regions were observed, and the ratio of the number of diamond abrasive grains being substantially parallel was determined. The same measurement was performed on all 10 dressers.

  The pad was actually ground using the produced dresser. The pad is made of foamed polyurethane and the pad diameter is 250 mm. This pad was affixed on the polishing machine. A dresser was fixed to a device having a rotating mechanism and a swinging mechanism in the radial direction of the pad, and a weight of 2.5 kg was applied by the pressurizing mechanism and pressed against the pad. While the center of the dresser was aligned with the center of the pad, the dresser was swung in the radial direction within a range of 30 mm to 90 mm from the center of the pad. The pad rotation speed was 95 rpm, the dresser rotation speed was 85 rpm, and the swing was 10 reciprocations / minute. The pad rotation direction and the dresser rotation direction were the same. Water was supplied to such an extent that the entire grinding surface was covered with a water film.

  When 5 minutes had elapsed after the start of grinding, the grinding was interrupted once, and the pad thickness was measured. The pad thickness was measured with a micrometer along two diameters orthogonal to each other. One diameter was equally divided into 10 parts at equal intervals, and an average of measured thickness values at 20 points near the middle of the equally divided part was obtained to obtain a pad thickness. Grinding was continued again, and after 10 hours, 15 hours and 20 hours, grinding was interrupted and the pad thickness was measured in the same manner.

  The pad grinding rate was determined from the reduction in pad thickness and the grinding time.

  The pad flatness was evaluated as a value obtained by subtracting the minimum value from the maximum value among the 20 pad thickness values measured after each grinding time. However, since the dressing effect was not sufficiently obtained after 5 minutes, the flatness was not evaluated.

  As a comparative material, a dresser was manufactured by a conventional method. First, as in the above example, the brazing material was spot welded to a predetermined portion of the stainless steel support material, and the support material and the brazing material were integrated by vacuum heat treatment. Next, an organic paste was thinly and uniformly applied on the brazing material. A metal sieve was placed on the brazing material. The size and interval of the openings of the metal sieve were the same as those used in the examples. After spraying diamond abrasive grains on the sieve, excess abrasive grains on the sieve were removed. After the metal sieve was gently removed, it was inserted into a vacuum heating furnace and brazed at 1010 ° C. for 10 minutes. In this way, a total of 10 dressers as comparative materials were produced. The ratio of the number of diamond abrasive grains substantially parallel to the metal support, the pad grinding rate, and the pad flatness were similarly determined.

  In both the dresser of the present invention and the dresser of the comparative material, the diamond abrasive grains did not fall off after the pad grinding.

  The results are shown in Table 1 and Table 2.

  As can be seen from the results of Table 1, the ratio of the substantially parallel diamond abrasive grains of the dressers No. 1 to No. 10 which are the examples of the present invention is 80% or more. The reason why the ratio of the number of substantially parallel abrasive grains is 81% to 94% by the same manufacturing method is considered to be that some of the diamond grains in a substantially parallel state fluctuate during brazing. It is done. In any case, the above ratio was 80% or more. Regarding the result after pad grinding, according to the dresser of the present invention, the pad grinding rate is high, and even when the usage time is long, the reduction of the grinding rate is suppressed. Also, the pad flatness has almost no use time dependency, and an excellent value of 1 μm or less is maintained.

  On the other hand, as can be seen from the results in Table 2, in the dresser produced by the conventional manufacturing method of No. 11 to No. 20 as a comparative example, the ratio of the substantially parallel diamond abrasive grains is 23 to 37%. Compared to the dresser, it is less than half. The grinding rate is lower than that of the dresser of the present invention, and the decrease due to the use time is also large. The flatness also decreases to nearly 3 μm, and the decrease due to the use time is also large.

[Example 2]
Single crystal artificial diamond abrasive grains having an average particle diameter of 3 μm, 6 μm, 12 μm, 50 μm, 85 μm, 150 μm, 200 μm, 280 μm, and 320 μm were used.

  Since it is not easy to regularly arrange abrasive grains having an average particle diameter of 3 μm and 6 μm, random arrangement was adopted. Specifically, a predetermined amount of single crystal artificial diamond abrasive grains is dispersed on the same alumina flat plate as in Example 1 to give a light vibration, and the crystal habit surface of the diamond abrasive grains is the surface of the flat plate. It was made to adhere to. The distance between the abrasive grains was about 5 μm for abrasive grains having an average grain diameter of 3 μm, and about 10 μm for abrasive grains having an average grain diameter of 6 μm.

  Abrasive grains having an average particle size of 12 μm to 320 μm were arranged at each vertex of the square matrix by the same method as in Example 1. The length of one side of the square of the matrix was set to 3 times the size of the abrasive grains. The size of the opening of the organic material sieve was 1.2 times the size of the abrasive grains. The thickness of the organic material sieve was 1.1 times the size of the abrasive grains.

  The material and shape of the metal support material and the arrangement region of the diamond abrasive grains were the same as in Example 1. First, a foil-like brazing material was temporarily attached by spot welding to an arrangement region of diamond abrasive grains of a stainless steel support material. The foil-like brazing material had a JIS standard BNi-2 composition, and the thickness was adjusted to 55% of the grain size of the abrasive grains. The support material on which the brazing material was spot-welded was subjected to heat treatment at 1000 ° C. for 5 minutes in a vacuum, and the brazing material was once melted on the support material and then solidified to integrate both.

  Cover the support plate with the brazing filler metal side facing down on the flat plate on which abrasive grains having an average particle size of 3 μm and 6 μm are dispersed, and braze the support and the diamond abrasive grains of the flat plate. Made contact. The subsequent procedure is the same as that of the first embodiment.

  Diamond abrasive grains having an average particle diameter of 12 μm to 320 μm were produced in the same manner as in Example 1. Three dressers were prepared for each size of abrasive grains. The ratio of the number of substantially parallel abrasive grains, pad grinding rate, and flatness were evaluated in the same manner.

  As shown in No. 21 to No. 23 of Table 3, when the average particle diameter of the diamond abrasive grains is less than 5 μm (3 μm), the ratio of the substantially parallel abrasive grains is less than 80%. . The pad flatness is improved, but the pad grinding rate is as small as 1 μm / min. With such a low pad grinding rate, the dressing time becomes long, which causes a problem of lowering productivity. On the other hand, as shown in No. 45 to No. 47 of Table 3, in the dresser having the average particle diameter of the diamond abrasive grains exceeding 300 μm, the flatness decreased by exceeding 1 μm.

  As shown in No. 24 to No. 44 of Table 3, in a dresser having an average particle diameter of diamond abrasive grains of 6 μm to 280 μm, the ratio of substantially parallel diamond abrasive grains was 80% or more. In the dresser of the present invention, the pad grinding rate is high, and even when the usage time is long, the reduction of the grinding rate is suppressed. Even in the flatness, there is almost no dependence on the use time, and an excellent value of 1 μm or less is maintained.

DESCRIPTION OF SYMBOLS 1 Brazing material 2 Metal support material 3 Single crystal abrasive grain 4 Flat board

Claims (5)

A polishing cloth dresser in which a plurality of abrasive grains are fixed to a single layer on the surface of a metal support,
Each of the abrasive grains is a single crystal abrasive grain having a plurality of crystal habit planes,
Of the total number of the fixed abrasive grains, the number of abrasive grains in which one of the plurality of crystal habit planes is arranged substantially parallel to the surface of the support material is 80% or more. A dresser for polishing cloth characterized by   The dresser for polishing cloth according to claim 1, wherein an average particle diameter of the abrasive grains is 5 µm or more and 300 µm or less.   The dresser for polishing cloth according to claim 1 or 2, wherein the abrasive grains are brazed to the surface of the metal support material.   The abrasive cloth dresser according to any one of claims 1 to 3, wherein the abrasive grains are diamond abrasive grains.   The dresser for abrasive cloth according to any one of claims 1 to 4, wherein the metal support is made of stainless steel.

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