JP2002346927A - Cmp conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sharp conditioner that does not give too much load on a workpiece. SOLUTION: A hollow area 21 provided with no abrasive grain is provided at a center of a surface of a grinding wheel base body 19. An abrasive grain layer area is provided in the outside of the hollow area 21. A first abrasive grain layer area 23 in the abrasive grain layer area is provided with plural lines of small abrasive grain layer portions 25 wherein plural diamond super- abrasive grains are adhered on a protuberance portion by an alloy plating phase at intervals. A second abrasive grain layer area 24 in the outside of the first abrasive grains layer portion 23 is structured by a ring-shaped circumferential abrasive grain layer portion 26 wherein super-abrasive grains are adhered on a ring-shaped circumferential protuberance portion by the alloy plating phase. In a surface of the grinding wheel base body 19, at least a surface of the hollow area 21 is covered by a synthetic resin layer R having water repellency.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrodeposition grindstone for conditioning a work material such as a polishing pad used when a surface of a work material such as a semiconductor wafer is polished by a CMP apparatus. The present invention relates to a CMP conditioner (hereinafter, simply referred to as a conditioner).

[0002]

2. Description of the Related Art As an example of a CMP apparatus (chemical mechanical polishing machine) for chemically and mechanically polishing the surface of a semiconductor wafer (hereinafter, simply referred to as a wafer) cut from a silicon ingot, as shown in FIG. There is a device. In this CMP apparatus 1, a polishing pad 4 made of, for example, hard urethane is provided on a disk-shaped rotary table 3 attached to a center shaft 2 as shown in FIG. A wafer carrier 5 capable of rotating is arranged at a position eccentric from the center axis 2 of the pad 4. The wafer carrier 5 has a disk shape smaller in diameter than the pad 4 and
The wafer 6 is disposed between the wafer carrier 5 and the pad 4 and is subjected to polishing of the surface on the pad 4 side to be mirror-finished.

The mechanism of polishing by CMP is based on a mechano-chemical polishing method in which a mechanical element (free abrasive grains) made of fine-particle silica or the like is combined with an etching element made of an acidic solution, an alkaline solution or the like. At the time of polishing, a liquid slurry s in which free abrasive grains and an acid solution are mixed is supplied onto the pad 4, so that the slurry s flows between the wafer 6 held on the wafer carrier 5 and the pad 4. Then, one surface of the wafer 6 is polished by the pad 4. A number of fine foam layers for holding the slurry s are provided on the pad 4 made of hard urethane or the like for polishing the wafer 6, and the wafer 6 is polished by the slurry s held in the foam layer. Will be However, the repetition of the polishing of the wafer 6 causes the flatness of the polished surface of the pad 4 to be reduced or clogging, resulting in a problem that the polishing accuracy and the polishing efficiency of the wafer 6 are reduced.

For this reason, conventionally, the CMP apparatus 1 has
As shown in FIG. 2, a pad conditioner 8 is provided so that the surface of the pad 4 is periodically re-ground or re-ground (conditioned). The pad conditioner 8 is provided with an electrodeposition wheel as a conditioner 11 via an arm 10 on a rotating shaft 9 provided outside the rotary table 3. Then, while polishing the wafer 6 with the wafer carrier 5 or in a state where the polishing of the wafer 6 is stopped, the pad 4 is
Is polished to restore or maintain the flatness of the pad 4 and to eliminate clogging of the foam layer of the pad 4.
The conditioner 11 generally has a configuration in which an abrasive grain layer in which superabrasive grains such as diamond are fixed by electroplating with Ni or a Ni-based alloy or the like is formed on a base metal. An example of such an electrodeposited wheel is disclosed in JP-A-9-19868.
There is one described in Japanese Patent Publication No. The electrodeposited wheel has a plurality of superabrasive grains fixed on a grinding surface, and island-like abrasive grain layers are dispersed over the entire surface. When this electrodeposited wheel is used as a conditioner in a CMP apparatus, the conditioner performs conditioning of the pad 4 while rotating.

[0005]

In this conditioner, chips located near the center are pressed against the pad 4 together with the slurry because the peripheral speed of the island-like abrasive layer provided near the center is low, and the chips are removed. There is a drawback that the discharge of water is not performed smoothly. There is also a disadvantage that the abrasive grains located near the center of the conditioner with a small peripheral speed are subject to a large load, so that the abrasive grains are easy to be crushed. There is a problem that many scratches occur. As another electrodeposition wheel disclosed in JP-A-11-77536, an abrasive layer is formed in a ring shape on the outer peripheral side of the grindstone substrate surface, and when this electrodeposition wheel is used as a conditioner, The surface pressure (grinding pressure) applied to the region of the pad 4 to be ground with the ring-shaped abrasive layer is excessively applied, so that the pad is excessively shaved and the life of the pad 4 is shortened. The present invention has been made in view of such problems,
It is an object of the present invention to provide a conditioner with good sharpness without excessive load on a work material.

[0006]

According to the CMP conditioner of the present invention, a hollow area where no abrasive grains are provided is provided at the center of the surface of the grinding wheel base, and (electrodeposition) is provided outside the hollow area. Abrasive grain layer area is provided, and the abrasive grain layer area is provided with a plurality of small abrasive grain layer parts in which one or a plurality of abrasive grains are fixed by a metal bonding phase at intervals. And Since the small abrasive layer portion provided on the outer peripheral side of the grinding surface, which is the surface of the grinding wheel base, has a high peripheral speed and is dispersedly arranged in a spot shape, the sharpness of the work material such as a pad is good, and Since the material is not subjected to an excessive load, the grinding
Conditioning can be performed. In addition, by providing a hollow area without abrasive grains in the center, grinding is not performed in the central part of the conditioner with a small peripheral speed even by rotary grinding, so chips stay in the central part and excessive load on abrasive grains. There is no crushing.

In the CMP conditioner according to the present invention, a hollow area where no abrasive grains are provided is provided in the center of the surface of the grinding wheel base, and an abrasive layer (by electrodeposition) is provided outside the hollow area. A first abrasive grain layer area in which a plurality of small abrasive grain layer portions each having one or more abrasive grains fixed by a metal binding phase are provided at intervals from each other; It is characterized by comprising a substantially ring-shaped second abrasive grain layer region in which a plurality of abrasive grains are fixed with a metal binding phase outside the first abrasive grain layer region. In the present invention, in particular, by providing the second abrasive grain layer region in a substantially ring shape on the outer peripheral side of the abrasive grain layer region, the second abrasive grain layer region is applied to the work material when grinding the work material such as a pad. Since the small abrasive layer portion of the first abrasive grain layer area comes into contact with the workpiece substantially in the form of a spot, the surface pressure when pressing the workpiece material in the second abrasive grain layer area is too high. In addition, it is possible to perform sharp grinding in the first abrasive grain layer region. As a result, excessive cutting of the work material can be suppressed, and stagnation of chips and crushing of abrasive grains at the center can be prevented.

In the CMP conditioner according to the present invention, a hollow area where no abrasive grains are provided is provided in the center of the surface of the grinding wheel base, and an abrasive grain layer area (by electrodeposition) is provided outside the hollow area. A first abrasive grain layer region in which a plurality of small abrasive grain layer portions each having one or a plurality of abrasive grains fixed by a metal binding phase are provided at intervals from each other; A substantially arc-shaped abrasive grain layer portion in which a plurality of abrasive grains are fixed by a metal bonding phase outside of one abrasive grain layer area is constituted by a second abrasive grain layer area arranged in a ring shape through a slit. It is characterized by the following. By providing a slit in the second abrasive grain layer region, chips and slag generated by grinding in the small abrasive grain layer portion in the first abrasive grain layer region and in the second abrasive grain layer region can be discharged through the slit.

The outer peripheral side surface of the second abrasive grain layer region may be formed in a tapered or arcuate shape in a longitudinal sectional view. When grinding a work material such as a pad with a rotating conditioner, the work material moving at the time of cutting is gradually brought into contact with the cross-sectional taper surface or circular arc surface of the second abrasive grain layer area, and the grinding area Can be started smoothly and smoothly. On the other hand, if the corners are formed on the outer peripheral side surface as in the conventional ring-shaped abrasive grain layer, there is a disadvantage that the pad or the like is easily peeled off at the start of grinding. When the outer diameter of the grindstone base is D and the radial width of the substantially ring-shaped abrasive grain layer area is W, the width W of the abrasive grain layer area is 1 of the outer diameter D.
It may be set in the range of 0% to 42%. If the width W of the abrasive grain layer region is smaller than 10%, the surface pressure or the grinding / polishing pressure becomes too high and the work material is cut too deep. If the width W exceeds 42%, chips and slag are pushed or excessively increased on the inner peripheral side. The abrasive grains are crushed by the load, and the flatness of the work material is reduced. When the outside diameter of the grindstone base is D and the diameter of the hollow region is L, the diameter L of the hollow region may be set in the range of 80% to 16% of the outside diameter D. 80% hollow area without abrasive grains
If it is larger, the surface pressure of the abrasive layer or the grinding / polishing pressure will increase, and the work material will be cut too deeply.
If the amount is less than%, there is a disadvantage that chips and slag are pushed in on the inner peripheral side and abrasive grains are crushed due to an excessive load, and the flatness of the work material is reduced.

In the abrasive grain layer region, a plurality of raised portions may be provided at intervals in the first abrasive grain layer region, and the small abrasive grain layer portions may be provided in these raised portions. Since the small abrasive layer on the raised portion protrudes from the surface of the abrasive layer without the raised portion, it is possible to set the grinding pressure on each superabrasive grain higher by preventing solid contact with the work material and further sharpening. Can be good. The number of superabrasive grains provided in the small abrasive layer portion is 1 to 500, and the ratio of the abrasive grain electrodeposited portion of the abrasive layer layer region to the total area of the grindstone substrate surface in plan view is 1
It may be set in the range of 0% to 30%. When the number of superabrasive grains is more than 500, there is a disadvantage that the superabrasive grains are easily clogged. If the total area of the abrasive grains is less than 10%, the load applied to each abrasive grain during grinding is too large, and the abrasive grains are likely to fall off, shortening the life. There is a risk of scratching the surface, and if it exceeds 30%, the conditioner may be clogged.

Here, in the CMP conditioner,
Chips and slurries of the work material such as pads are likely to adhere to the surface of the grinding wheel base, and chips that have fallen as a lump from this surface and slurries that have changed due to aging while adhering to the surface May remain on the surface of the work material or damage the surface of the work material.
In the case of a pad of an MP apparatus, the number of scratches generated by a lump of chips remaining on the pad or a deteriorated slurry may increase on the surface of the semiconductor wafer polished using the pad. Thus, by covering at least the surface of the hollow region in the grinding wheel base with a synthetic resin layer having water repellency, it is possible to make it difficult for chips or slurry of the pad to adhere to the surface of the grinding wheel base. Here, the water-repellent synthetic resin layer may be formed not only in the hollow region on the surface of the grindstone substrate but also in the abrasive grain layer region. However, when this synthetic resin layer is formed on the surface of the portion where the abrasive grains are provided, the thickness of the synthetic resin layer is adjusted or the synthetic resin layer is formed so that the abrasive grains act on the polishing of the work material. After performing formation, we perform indexing,
The tips of the abrasive grains are exposed from the surface of the synthetic resin layer. Furthermore, when a synthetic resin layer having water repellency is formed in a region that does not act on the grinding of the work material, that is, in a hollow region, a portion where no abrasive grains are provided (non-abrasive portion) in the abrasive grain layer region,
Since the synthetic resin layer is not directly rubbed by the work material, the synthetic resin layer is less likely to be scraped or peeled off, and the life of the synthetic resin layer can be extended. Further, as the synthetic resin constituting the synthetic resin layer having the water repellency, a fluorine-based resin, for example, a composition for a room-temperature-curable fluorine paint by a combination of a fluoroepoxy compound and an aminosilicone, and a fluoroolefin resin as a base. Resin-soluble fluororesin for thermosetting paint, polytetrafluoroethylene (PTFE), tetrafluoroethylene-perfluoroalkylvinyl ether copolymer (PFA), polychlorotrifluoroethylene (PC
TFE) or the like is used.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings, in which the same portions as those of the above-described prior art will be described using the same reference numerals. 1 to 5 relate to the first embodiment, FIG. 1 is a plan view showing a ground surface of a conditioner, FIG. 2 is a central longitudinal sectional view of the conditioner shown in FIG. 1, and FIG. FIG. 4 is a view showing the influence of electrodeposition plating on the grinding wheel base, wherein FIG. 4A is a side view of the grinding wheel base, and FIG. Diagram of plating state,
(C) is a diagram showing a state in which the entire surface of the grindstone substrate is electrodeposited, and FIG. 5 is a diagram showing a state in which the conditioner starts grinding on the outer peripheral side surface of the pad. A conditioner 20 as an electrodeposited wheel (electroplated whetstone) for CMP according to the embodiment shown in FIGS. 1 and 2 has a substantially circular shape of a disk-shaped whetstone substrate 19 (base metal) made of, for example, stainless steel. For example, a substantially circular hollow region 21 where no abrasive layer is provided is formed substantially concentrically at the center on the surface 19a, and a substantially ring-shaped abrasive layer region 22 is substantially concentric (outside eccentric) outside the hollow region 21. Good). In addition, conditioner 20
Constitutes a single-layer grindstone provided with only one superabrasive grain.

Further, in this conditioner 20,
At least the hollow region 2 of the surface 19a of the grinding wheel base 19
1 is covered with a synthetic resin layer R having water repellency. The water-repellent synthetic resin layer R may be formed not only in the hollow region 21 of the grindstone base 19 but also in the abrasive layer region 22. However, the abrasive grain layer area 2
2, the synthetic resin layer R is formed on the surface of the portion where the abrasive grains are provided (the small abrasive layer portion 25 of the first abrasive layer region 23 and the circumferential abrasive layer portion 26 of the second abrasive layer region 24). When forming the synthetic resin layer R, adjust the thickness of the synthetic resin layer R so that the abrasive grain acts on the grinding of the work material, or perform the indexing after forming the synthetic resin layer R. Is exposed from the surface of the synthetic resin layer R. Further, the synthetic resin layer R is formed so that the surface shape (irregularity) of the grindstone base 19 is left, that is, the small abrasive layer 25 and the circumferential abrasive layer 26 on the surface 19a of the grindstone base 19 are at high places. The small abrasive layer 25 and the circumferential abrasive layer 26 from the surface are placed so that the other parts are low.
The thickness is set to be thinner than the protrusion amount of the workpiece, whereby the small abrasive layer portion 25 and the circumferential abrasive layer portion 26 come into contact with the workpiece at the time of grinding the workpiece, and the grinding is performed in other portions. It is designed such that a gap is formed between the material and the cutting material. In the present embodiment, the synthetic resin layer R is formed not only in the hollow region 21 but also in a portion where the abrasive grains including the abrasive grain layer bottom 23a of the first abrasive grain layer area 23 described later are not provided in the abrasive grain layer area 22. (This portion is referred to as a non-abrasive portion). Here, in the present embodiment, the synthetic resin constituting the above synthetic resin layer R having water repellency has water repellency and oil repellency as surface characteristics,
Non-tacky, fluorine-based resin that is a synthetic resin having high sliding properties, such as a composition for a room temperature-curable fluorine paint by a combination of a fluoroepoxy compound and an aminosilicone, and a solvent-soluble heat based on a fluoroolefin resin. Fluororesin for curable coatings, polytetrafluoroethylene (PTFE), tetrafluoroethylene
Perfluoroalkyl vinyl ether copolymer (PF
A), polychlorotrifluoroethylene (PCTFE)
Are used.

The abrasive grain layer region 22 includes a ring-shaped first abrasive grain layer region 23 on the inner peripheral side and a ring-shaped second abrasive grain layer region 24 on the outer peripheral side. The first abrasive grain layer region 23 is configured by providing a plurality of small abrasive grain layer portions 25 at predetermined intervals, and the second abrasive grain layer region 24 is configured in a substantially ring shape in plan view.
As shown in FIG. 3, the first abrasive grain layer region 23 has
Are formed at a predetermined interval from the surface 19a of the hollow region 21 (in the embodiment, the hollow region 21).
Are arranged in three rows in a ring shape around the
9, super-abrasive grains 30 such as diamond super-abrasive grains are fixed along a substantially cylindrical side surface, a corner R portion, and a top surface by electroplating or the like with a metal plating phase 31 made of Ni or a Ni-based alloy. The grain layer 25 is formed. Moreover, in the first abrasive grain layer region 23, the superabrasive grains 30 are fixed only on the respective raised portions 29, and are not provided on the abrasive grain layer bottom portion 23a between the raised portions 29.

In each small abrasive layer portion 25, for example, 1 to 500, preferably 11 to 500, superabrasive grains 30 are fixed to the entire surface thereof with a metal plating phase 31. Although it is possible to grind with one or more superabrasive grains 30,
If the number is less than 11, it is difficult to continuously perform the rough grinding and the finish grinding on the pad 4, and if the number is more than 500, the superabrasive grains 30 are likely to be clogged. Each small abrasive layer portion 25 has a maximum diameter d in the range of φ1 to 10 mm, and the height H from the abrasive layer bottom portion 23a is equal to or greater than the average particle size of the superabrasive particles 30, and preferably equal to or greater than twice the average particle size. The average particle size of the superabrasive particles 30 is set to 1 mm or less, for example, 0.1 mm
Set to about 0.7 mm. The reason why the height H is equal to or larger than the average particle size of the superabrasive particles 30 is that the superabrasive particles 30
This is to prevent only the abrasive layer from coming into contact with the pad 4 by grinding only the pad layer 4 so that the grinding process is performed. It is assumed that the small abrasive layer portions 25 are at the same height. The average particle size of the superabrasive particles 30 was determined by a particle size distribution defined by JIS 4131 and by a calculated value based on a phase average.

In the second abrasive grain layer region 24, a ring-shaped circumferential ridge 32 projecting from the surface 19 a of the grindstone substrate 19 is provided on the outer peripheral side of the first abrasive grain layer region 23, for example.
And a plurality of superabrasive grains 30 are entirely formed on the surface of the circumferential ridge 32 by a metal plating phase 31 such as Ni.
To form a circumferential abrasive grain layer portion 26, and the outer circumferential convex curved portion 35 of the circumferential abrasive grain layer portion 26, particularly the outer circumferential side wall, has a convex section R having a gentler slope than the inner side wall. It is formed in a curved shape. Therefore, the pad 4 can be prevented from peeling off at the start of grinding. Further, instead of the cross section R, the outer circumferential convex portion 35 may have a tapered cross section. In addition, the area of the superabrasive electrodeposited portion with respect to the entire area of the surface 19a (ground surface) in plan view of the conditioner 20 is set in the range of 10% to 30%. If the area of the superabrasive grain electrodeposited area is less than 10%, the grinding efficiency is poor, the superabrasive grains 30 are likely to fall off, the life is shortened, and the superabrasive grains 30 are put on the pad 4 and the pad 4 or the pad 4 There is a possibility that the wafer polished by using Scratch may be scratched. If it is more than 30%, the conditioner 20 may be clogged.

1 and 2, the surface 19a of the conditioner 20 has a substantially circular plate shape having an outer diameter D, the diameter of the hollow region 21 is L, and the ring-shaped abrasive grain layer region 2 is formed.
If the radial width of 2 is W, D = L + 2W. Moreover, the width W of the abrasive grain layer region 22 is set to 10% to 42%. In other words, the diameter L of the hollow region 21 is set in the range of 16% to 80% with respect to the outer diameter D of the conditioner 20. Within the above range, there is obtained an advantage that the flatness, that is, the surface roughness, of the work material such as the pad 4 during polishing is good, the sharpness is good, and the life of the work material is long. Here, the width W of the abrasive grain layer region 22 is larger than 42% (the diameter L of the hollow region 21).
Is smaller than 16% of the outer diameter D), the flatness of the polished surface of the work material is poor, the load applied to the superabrasive grains on the inner peripheral side becomes excessive, and it is easy to be crushed, and the width W is smaller than 10% (diameter). L is 80%
However, there is a disadvantage in that the grinding / polishing pressure increases and the work material such as the pad 4 is cut too deeply, so that the wear rate of the pad 4 and the like increases remarkably.

This will be further described with reference to FIG.
Assuming that the grindstone base 19 is a parallel plate-shaped disk type as shown in FIG. 2, the rotation axis O is set to a direction substantially perpendicular to the surface 19a, and when an abrasive layer is formed on the surface 19a by plating, a convex curved surface is formed on the abrasive layer side. Conditioner 20 (whetstone substrate 1)
9) Warpage occurs. In this case, the convex curved surface of the surface 19a forms a convex curved surface concentrically in the direction of the rotation axis O, assuming that a point near the rotation axis O projects most. Here, as for the conditioner 20, for example, when an abrasive layer is formed by plating on the entire surface 19a as shown in FIG. 3C, the height s (for example,
S is about 30 μm at maximum, with the outer diameter of
This causes a warp, which results in a warp having a height difference s in the abrasive grain layer. In that respect, the ring-shaped abrasive layer region 22 (for example, the rotation axis O) is formed only on the outer portion of the surface 19a like the conditioner 20 according to the present embodiment shown in FIG.
If the plating is formed, the surface 19a is formed by electrodeposition plating.
Even if warpage (deformation) occurs, warpage itself can be suppressed to a relatively small value. Moreover, the height difference s1 in the abrasive grain layer region 22
(<S) is smaller than that formed by plating on the entire surface 19a, and the flatness of the abrasive grain layer region 22 is higher, so that the adverse effect of the warpage on the flatness is further suppressed. -Polishing accuracy can be further improved. still,
In order to manufacture the conditioner 20, the central portion of the surface 19a of the grindstone base 19 is masked or taped over a range of a diameter L corresponding to the hollow region 21, and each raised portion 29. After performing masking except for the peripheral ridges 32, plating is performed such as electrolytic plating, and then, masking and taping applied to a region corresponding to the hollow region 21 are removed, and each ridge 29 ... and each circle are removed. Circumference 3
The masking applied except for 2 ... is removed. Then, after covering the surfaces of the protruding portions 29 and the circumferential protruding portions 32 by masking, the synthetic resin is applied to the surface 19a to form a synthetic resin layer R (the portion where the abrasive grains are provided). This masking operation is unnecessary when the synthetic resin layer R is also formed on the surface.) Here, the synthetic resin layer R
The method of forming is appropriately selected depending on the properties of the synthetic resin to be used.
In addition to forming the synthetic resin layer R only by applying it to 9a, the synthetic resin layer R is formed by heating and baking the synthetic resin after the application as necessary.

The conditioner 20 according to the present embodiment has the above-described configuration.
A method of polishing a pad using a CMP apparatus will be described. In the CMP apparatus 1 shown in FIG. 12, a polishing pad 4 made of, for example, hard urethane is provided on a rotary table, and a conditioner 20 is rotatably mounted at an eccentric position with respect to the pad 4, and a worn pad. In the case of re-polishing the surface of the pad 4, the conditioner 20 rotates the pad 4 in the same direction as the pad 4, thereby polishing the surface of the pad 4 and restoring the flatness of the surface of the pad 4, thereby reducing the clogging of the foam layer. Will be resolved. Incidentally, the conditioner 20 can be mounted on the wafer carrier 5 to perform the polishing operation.

In the state of polishing by the conditioner 20, the pad 4 is brought into contact with the pad 4 in the outer peripheral abrasive grain layer region 22, and in particular, in the ring-shaped second abrasive grain layer region 24, the pad 4 covers the entire circumference with its width. Since the small abrasive grain layer portions 25 in the first abrasive grain layer region 23 are in contact with each other, it is possible to prevent the small abrasive grain layer portions 25 from being excessively loaded and biting into the pad. The pad 4 can be sharply ground by abutting the pad 4 in a shape. Since the opening of the foam layer of the pad 4 is cut cleanly by the small abrasive layer 25 and the opening is not crushed, the holding capacity of the slurry can be maintained at a high level. Moreover, since the solid does not contact, the grinding fluid inside the foamed layer is not repelled at the time of grinding, and the grinding is performed in a state containing water. In grinding, as shown in FIG. 5, the outer peripheral convex portion 35 of the circumferential abrasive layer portion 26 of the rotating conditioner 20 cuts into the pad 4 rotating in the same direction and starts grinding. The pad 4 can be ground so that the grinding area gradually increases due to the gentle inclination of the portion 35, and the turning-over of the pad 4 can be prevented. On the other hand, in the conventional conditioner, since the outer peripheral edge of the abrasive grain layer stands up at a substantially right angle in cross section, the load at the time of cutting is large and the pad 4 may be peeled off. Furthermore, since at least the surface of the hollow region 21 where the abrasive grains are not provided on the surface 19a of the grindstone substrate 19 is covered with the synthetic resin layer R having water repellency, chips and slurries hardly adhere to this portion. Become. Further, in the present embodiment, the synthetic resin layer R is formed in a non-abrasive portion where no abrasive grains are provided in a region that does not affect the polishing of the work material, that is, in the hollow region 21 and the abrasive grain layer region 22. Since the synthetic resin layer R does not come into direct contact with the work material and is not rubbed by the work material, the synthetic resin layer R is less likely to be scraped or peeled off, thereby extending the life of the synthetic resin layer R. be able to.

As described above, according to the present embodiment, since the high-speed grinding is performed in the abrasive layer region 22 on the outer peripheral side of the grindstone substrate 19, the sharpness is good, and the abrasive layer is provided in the low-speed hollow region 21. Since the abrasive grains are not crushed due to an excessive load applied to the abrasive grains, the chips can be discharged smoothly without staying in the vicinity of the center as slag together with the slurry or being pressed against the pad 4. Moreover, since the abrasive grain layer region 22 is formed of the first and second abrasive grain layer regions 23 and 24 on the inner and outer circumferences, the second abrasive grain layer region 24 on the outer peripheral side suppresses the excessively digging into the pad 4 and suppresses the inner surface. Each of the small abrasive layer portions 25 of the peripheral first abrasive layer portion 23 does not bite into the pad too much, and can be appropriately ground with sharpness. Moreover, the pad 4 is not peeled off on the outer peripheral side surface of the conditioner 20 because the outer peripheral convex portion 35 of the circumferential abrasive grain layer portion 26 gradually cuts and increases the grinding amount. Further, when the width W of the abrasive layer region is 10
%, The surface pressure (grinding / polishing pressure) becomes too high and the pad 4 is cut too deep.
The flatness is poor, and the abrasive load on the inner peripheral side becomes excessive, so that the sharpness of the abrasive layer layer region 22 is reduced. In particular, the occurrence of micro-scratch on the work material such as the pad 4 on the center side increases.

Further, on the surface 19a of the grindstone substrate 19, the hollow region 21 where the abrasive grains are not provided and the abrasive layer region 2
In FIG. 2, the portion where the abrasive grains are not provided is covered with the synthetic resin layer R having water repellency, and chips and slurries are hardly adhered, and chips and slurries are quickly discharged. Inconveniences such as the chips falling off as a lump, and the slurry adhering to the conditioner 20 and being deteriorated due to aging or the like are unlikely to occur, and the lump of chips dropped from the conditioner 20 and the deteriorated slurry are hardly cut. The risk of remaining on the surface or damaging the surface of the work material is reduced. Thereby, even when the work material is a pad of a CMP apparatus used for polishing a semiconductor wafer to a mirror surface or the like, the surface of the semiconductor wafer polished using this pad is scratched by a lump of chips or a degraded slurry. Can hardly occur.

Next, another embodiment of the present invention will be described. The same or similar members and portions as those of the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted. A second embodiment will be described with reference to FIG. FIG. 6 is a plan view showing a conditioner 40 for CMP according to the second embodiment.
The conditioner 40 has substantially the same configuration as the conditioner 20 according to the first embodiment, and has radial slits 41 at predetermined intervals in the second abrasive grain layer region 24.
Is formed and divided into an appropriate number of substantially circular arcs. That is, in the second abrasive grain layer region 24, for example, eight arc-shaped protrusions having a central angle from the center O of the grinding wheel base body 19 of, for example, about 45 ° are formed in a circular array with the slit 41 interposed therebetween. It is formed in a substantially ring shape as a whole. A plurality of superabrasive grains 30 are fixed to the entire surface of each arc ridge by the metal plating phase 31 so that the arc abrasive grain layer section 42 is formed.
Are formed on the outer peripheral side wall of each of the arc-shaped abrasive grain layer portions 42, and a gently inclined outer peripheral convex portion 35A having the same configuration as that of the first embodiment is formed. Note that the bottom surface of the slit 41 is preferably the same height as the abrasive grain layer bottom portion 23a. In the present embodiment, the synthetic resin layer R is also formed on the bottom surface of the slit 41. According to the conditioner 40 of this embodiment, in addition to the effects of the first embodiment, chips, slurries, slag, and the like can be more smoothly discharged to the outside through the slits 41 during grinding. Further, since a synthetic resin layer is formed on the bottom surface of the slit 41, chips and slurries hardly adhere to the slit 41, and the slit 41 is hardly clogged, so that chips and slurries can be discharged through the slit 41 more smoothly. Can be done.

Next, a third embodiment will be described with reference to FIG. FIG. 7 is a plan view showing a conditioner 50 for CMP according to the third embodiment. This conditioner 5
0 is the first abrasive grain layer area 23 in the abrasive grain layer area 22
Not only the second abrasive layer region 24 but also the small abrasive layer portion 2
5 are separated from each other and arranged at predetermined intervals in the circumferential direction. That is, the outer peripheral abrasive layer layer region 2 excluding the hollow region 21
A plurality of small abrasive grain layer portions 25 are separated from one another at a predetermined interval and arranged in a ring shape in a plurality of rows in the circumferential direction. In this conditioner 50 as well, the synthetic resin layer R is formed on the surface of the abrasive grain layer bottom portion 23a of the hollow area 21 and the abrasive grain layer area 22 to prevent chips and slurry from adhering. Therefore, during grinding, the entire small abrasive layer portion 25 of the abrasive layer region 22 contacts the pad in a substantially spot-like shape, and the width W of the abrasive layer region 22 is 10 mm of the outer diameter D.
In this case, since the surface pressure is not excessively increased and the superabrasive grains 30 do not penetrate deeply into the pad 4, the conditioning for sharply recovering the flatness can be performed without excessive grinding. Moreover, since the super-abrasive grains 30 are not provided in the hollow area 21 having a small peripheral speed, the pad 4
Therefore, there is an effect that it is possible to prevent chips and slag from being pushed into the pad 4 and to stay there, with few micro scratches occurring on the pad 4.

In each of the above-described embodiments, the small abrasive layer portions 25 are arranged in a plurality of rows concentrically. However, the present invention is not limited to this. In the range of the width W of the grain layer region 22, a number of small abrasive grain layer portions 25 may be arranged in a matrix, mesh, spiral, or the like. Further, in the circumferential abrasive layer portion 26 and the arc abrasive layer portion 42 of the second abrasive layer region 24 provided in the conditioners 20 and 40 in the first and second embodiments,
The arrangement density of superabrasive grains 30 may be appropriately selected. Further, in each of the above embodiments, the raised portion 29 of the small abrasive layer portion 25 is formed in a substantially cylindrical shape, but the shape of the raised portion 29 is not limited to this, and the height from the abrasive layer bottom portion 23a It is sufficient that H is equal to or larger than the average particle diameter of the superabrasive grains 30, and for example, may be a convex curved surface such as a hemisphere or a triangular pyramid. The outer shape of the small abrasive layer portion 25 also has a shape following the shape.

Next, a polishing test performed on the characteristics of the conditioner of the present embodiment will be described. As a test example, the conditioner 20 according to the first embodiment is Example 1, the conditioner 40 according to the second embodiment is Example 2,
Third Embodiment A conditioner 50 according to a third embodiment is described as a third embodiment.
Shall be used as Conditioners 20, 4
Nos. 0 and 50 were produced by fixing superabrasive grains 30 of diamond with a metal plating phase 31 made of Ni plating. In Examples 1 and 2, the number of superabrasive grains fixed to one small abrasive layer 25 in the first abrasive layer 23 is 70, and the maximum outer diameter of each small abrasive layer 25 is 1 mm. did. The width of the circumferential abrasive layer portion 26 in the second abrasive layer region 24 is 3.5 mm, and the content ratio of the superabrasive particles 30 is 13% of the entire conditioner in area ratio.
%, And the remainder was provided in the small abrasive layer portion 25. In Example 3, each small abrasive layer portion 25 was the same as in Examples 1 and 2. In each of Examples 1 to 3, the outer diameter D of the grindstone base 19 was set to 100 mm, and the ratio of the width W of the abrasive grain layer region 22 to the outer diameter D was 5%, 10%, 20%, 30%, and 4%.
Six types of conditioners of 0% and 50% (the abrasive layer was provided on the entire surface) were manufactured respectively. In this case, in Examples 1 and 2, the second abrasive grain layer region 24 has a constant width regardless of the change in the width W, and the width of the first abrasive grain layer region 23 is changed according to the change in the width W. The abrasive layer area 22 was set. The polishing test according to Examples 1, 2, and 3 was performed under the following conditions. A precision lapping machine with a platen size of 600 mm was used as a CMP grinding machine, and the platen rotation speed was 45 mi.
n-1, the load of the conditioner 20 is 24N, the number of revolutions is 56m
in-1, the outer diameter of the wafer was 8 inches, the load was 24 N, the number of revolutions was 60 min-1, the pad 4 was Rodel-Nitta IC1000, and pure water was 17 ml / m as a lubricating liquid.
in was used.

Then, in the CMP grinding apparatus, the polishing of the wafer 6 is performed for 2 minutes simultaneously with the conditioning of the pad 4 by the conditioner of each embodiment, and the average polishing rate of the polished surface of the wafer 6 after polishing (polishing rate: polishing amount) ) Were measured, the results shown in FIG. 8 were obtained. Table 1 shows the wafer average polishing rate (angstrom / min) corresponding to each width W.

[0028]

[Table 1]

In FIG. 8, the polishing rates of the wafers 6 were 5%, 10%, and 2% for each of Examples 1 to 3.
Numerical values shown in Table 1 are shown as the values change to 0%, 30%, 40%, and 50% (the abrasive layer region is provided on the entire surface). The oxide film of the wafer 6 has a thickness of about 5000 angstroms, and it is usually necessary to polish and planarize the oxide film within 2 minutes to improve the polishing efficiency. For this purpose, a speed of at least 2500 Å / min is required. To satisfy this condition in each embodiment, it is desirable that W in FIG. 8 is 42% or less. When the pad polishing speed (μm / Hr) corresponding to the width W of the abrasive grain layer region was measured, the one shown in FIG. 9 was obtained. Table 2 shows the pad polishing rates corresponding to the respective widths W.

[0030]

[Table 2]

When the width W of the abrasive grain layer region 22 is 5%, the pad grinding / polishing pressure is high, and the pad polishing speed in Examples 1 to 3 is 80 μm / hr or more as shown in FIG. As pad wear progresses, the frequency of pad replacement is increased, leading to significant problems in terms of cost and labor. FIG.
When the width W is 10%, the pad polishing rate of each of Examples 1 to 3 is 50 to 60 μm / hr, which is much smaller than the width W = 5%. Moreover, when the width W is 10%, the grinding / polishing pressure of the pad becomes relatively small, and therefore, as shown in FIG.
4300 Å / min, and the average polishing rate of the wafer is reduced by 30% compared to the width W = 5%.
It is reduced by about 0 to 500 angstroms.
Therefore, the width W is preferably 10% or more.

Referring to FIG. 10, regarding the conditioner 20 of the first embodiment, the width W of the abrasive grain layer region 22 is 5%, 20%,
A conditioner of 50% (entire surface) was manufactured, and the wafer polishing rate at each grinding point was measured with the vertical axis representing the wafer polishing rate (angstrom / min). FIG.
0, the average polishing rate of the wafer was highest when the width W of the abrasive grain layer region 22 was 5%, and the width W was 20% next. When these abrasive grain layer regions are used, substantially uniform grinding / polishing characteristics can be obtained except for both ends (range of 5% or 3% outside) of the conditioner. However, when the width W is 5%, as shown in FIG. 9, the pad polishing speed is extremely high (83 μm
/ Hr) was not practical. When the width W is 50%, the flatness (in-plane uniformity) of the polishing rate is extremely poor, and a grinding / polishing action that cannot be used is exhibited.

Therefore, in this embodiment, the width W = 20%
Is the most uniform and economical in-plane polishing amount of the wafer,
When the width W = 5%, the pad polishing speed was too high, and when the width W = 50%, the in-plane polishing amount (the polishing amount at each grinding point in the radial direction) was extremely low. From the test results shown in FIGS. 8, 9, 10 and Table 1, W / D is 10% to 42% depending on the relationship between the average polishing rate of the wafer, the average polishing rate of the pad, and the uniformity of the in-plane polishing amount of the wafer. (The diameter L of the hollow region 21 is in the range of 16 to 80%). When an abrasive layer is provided on the entire surface 19a of the grinding wheel base 19 (W / D = 50%), as shown in FIGS. 8 and 9, both the wafer average polishing rate and the pad wear rate are the lowest, and the grinding efficiency is remarkable. It was bad.

Further, in the present embodiment, the surface of the hollow region 21 and the portion of the abrasive grain layer region 22 where the abrasive grains are not provided in the surface 19a of the grindstone base 19 are covered with the synthetic resin layer R having water repellency. And a conditioner having the same shape as the conditioner (here, the conditioner 20 shown in the first embodiment is used as an example and the width W of the abrasive layer region 22 is set to 20%). A conditioner having no synthetic resin layer R is prepared, and the wafer is polished simultaneously with the conditioning of the pad by each conditioner in a CMP apparatus.
After the polishing, the number of scratches having a length of 0.2 μm or more formed on the surface of the wafer was measured. The result is shown in FIG. Here, first, the wafers are polished one by one while polishing the pads with a conditioner having no synthetic resin layer R in the CMP apparatus.
The wafers were polished continuously for 25 wafers one by one while the conditioner was replaced with the conditioner of the present embodiment and the pads were polished by the conditioner of the present embodiment. From the results shown in FIG. 11, when the pad is polished using a conditioner without the synthetic resin layer R, the number of scratches generated on the wafer is irregularly increased and decreased. For this reason, in the conditioner in which the synthetic resin layer R is not provided, chips and slurries adhere to the surface of the grindstone substrate, and when these accumulate to some extent, lumps of chips and deteriorated slurry fall out of the conditioner and scratches occur. Is presumed to have occurred. On the other hand, in the conditioner of the present embodiment, the number of scratches generated is stable,
Since it is difficult for chips and slurries to adhere to the surface 19a of the grindstone base 19, it is presumed that these are quickly discharged before they are aggregated or deteriorated. From this test result, the conditioner in which the surface of the hollow region 21 on the surface 19a of the grindstone substrate 19 and the portion where the abrasive grains are not provided in the abrasive grain layer region 22 are covered with the synthetic resin layer R having water repellency, It was confirmed that scratches were less likely to occur on the wafer polished by the pad that was polished.

[0035]

As described above, the CM according to the present invention is used.
The P conditioner has a hollow region where no abrasive grains are provided in the center of the surface of the grinding wheel base, and an abrasive layer region is provided outside the hollow region. Since a plurality of small abrasive layer portions in which one or a plurality of abrasive particles are fixed with a metal bonding phase are provided at intervals, the small abrasive layer portion provided in the outer peripheral region of the grinding surface has a peripheral speed of Since the work material is high and sharp, and no excessive load is applied to the work material, it is possible to perform suitable cutting and conditioning without excessively cutting the work material. In addition, by providing a hollow area without abrasive grains in the center, grinding is not performed at the center of the conditioner with a small peripheral speed even by rotary grinding, so chips and slag etc. are pushed into the center and excessive abrasive grains No crushing due to heavy load.

Further, in the CMP conditioner according to the present invention, a plurality of small abrasive layer portions in which one or a plurality of abrasive grains are fixed by a metal binding phase are provided at intervals on the outer peripheral side of the hollow area. Since the first abrasive grain layer region and the ring-shaped second abrasive grain layer region in which a plurality of abrasive grains are fixed to the outer peripheral side of the first abrasive grain layer area with a metal binding phase, the pad Since the second abrasive grain layer area is in surface contact with the workpiece at the time of grinding the workpiece, etc., the small abrasive grain layer portion of the first abrasive grain layer area contacts the workpiece substantially in a spot shape, The surface pressure when pressing the work material in the first abrasive grain layer region is not excessively increased, and the first abrasive grain layer region can be appropriately sharply ground without excessive cutting, and excessive surface pressure This can prevent the work material from being excessively polished, and can prevent the accumulation of chips and the like.

Further, in the CMP conditioner according to the present invention, a plurality of small abrasive layer portions in which one or a plurality of abrasive grains are fixed with a metal bonding phase are provided at intervals in the abrasive layer region outside the hollow region. A first abrasive grain layer region, and a substantially arc-shaped abrasive grain layer portion in which a plurality of abrasive grains are fixed to the outer peripheral side of the first abrasive grain layer area with a metal binding phase are arranged in a substantially ring shape through a slit. Since it is configured with the second abrasive grain layer area, in addition to the above-described effects, the first abrasive grain layer area or the second abrasive grain layer area is generated by providing a slit in the second abrasive grain layer area. Chips can be discharged through the slit together with the slurry.

Further, since the outer peripheral side surface of the second abrasive grain layer region is formed in a tapered or arcuate shape in a longitudinal sectional view, the tapered sectional shape of the second abrasive grain layer region with respect to the work material at the time of grinding. Alternatively, since the grinding area gradually increases due to gradual contact with the arc-shaped outer peripheral side surface, grinding of a work material such as a pad can be started smoothly and smoothly, and there is no peeling. On the other hand, if corners are formed on the outer peripheral edge of the abrasive grain layer as in a conventional conditioner, there is a disadvantage that pads and the like are easily peeled off at the start of grinding. When the outer diameter of the grindstone substrate is D and the radial width of the substantially ring-shaped abrasive grain layer area is W, the width W of the abrasive grain layer area is 10% to 42% of the outer diameter D.
The advantage is that the flatness, that is, the surface roughness during polishing of the work material such as a pad is good, the sharpness is good, and the life of the work material is long, and the width of the abrasive layer region is set. W is 10
%, The grinding / polishing pressure becomes too high and the work material is cut too deep. If it exceeds 42%, the flatness of the work material decreases, the sharpness of the center is poor, and slag such as chips tends to accumulate.

Further, at least the surface of the hollow region where the abrasive grains are not provided on the surface of the grindstone substrate is covered with a synthetic resin layer having water repellency, so that chips and slurries are less likely to adhere, and chips and slurries are not formed. Since the chips are quickly discharged, inconveniences such as chips falling out of the conditioner as a lump and deterioration due to aging due to the adhesion of the slurry to the conditioner are less likely to occur. It is possible to reduce the risk that lumps or altered slurry remain on the surface of the work material or damage the surface of the work material. Thereby, even when the work material is a pad of a CMP apparatus used for polishing a semiconductor wafer to a mirror surface or the like, a lump of chips remaining on the pad and / or a lump of chips remaining on the surface of the semiconductor wafer polished using the pad are formed. Scratch due to the altered slurry can be made hard to occur.

[Brief description of the drawings]

FIG. 1 is a plan view of a conditioner according to a first embodiment of the present invention.

FIG. 2 is a central longitudinal sectional view of the conditioner shown in FIG.

FIG. 3 is a partial longitudinal sectional view showing first and second abrasive grain layer regions of the conditioner.

4A and 4B are diagrams showing the influence of electrodeposition plating on a grinding wheel base, wherein FIG. 4A is a side view of the grinding wheel base, and FIG. 4B is a state in which the surface of the grinding wheel base is electrodeposited by the present embodiment. FIG. 3C shows a conditioner according to the first embodiment of the present invention, and FIG.
FIG. 3 is a view showing a state in which the entire surface of the grindstone substrate is electrodeposited.

FIG. 5 is an explanatory diagram showing a state where grinding of a pad is started on the outer peripheral side surface of the conditioner.

FIG. 6 is a plan view of a conditioner according to a second embodiment of the present invention.

FIG. 7 is a plan view of a conditioner according to a third embodiment of the present invention.

FIG. 8 is a view showing polishing characteristics of each of the conditioners in which the width of the abrasive grain layer region is changed in Examples 1 to 3 by an average polishing rate of a wafer.

FIG. 9 is a diagram showing the polishing speed of the pad by each conditioner in which the width of the abrasive grain layer region is changed in each of Examples 1 to 3.

FIG. 10 shows that the width of the abrasive grain layer region is 5 in Example 1.
It is a figure which shows the wafer polishing rate in each grinding point in the radial position of a wafer in the case of%, 20%, and 50% (entire surface).

FIG. 11 shows a conditioner according to the present invention in which the surface of a hollow region on the surface of a grindstone base and a portion where no abrasive grains are provided in an abrasive layer region are covered with a synthetic resin layer, and is synthesized in the same shape as the conditioner. 20 μm formed on the surface of a wafer polished by a pad polished using each of the conditioners not provided with a resin layer
It is a figure showing the number of scratches of the above length.

FIG. 12 is a perspective view of a main part of a conventional CMP apparatus.

[Explanation of symbols]

20, 40, 50 Conditioner (CMP conditioner) 21 Hollow region 22 Abrasive layer region 23 First abrasive layer region 24 Second abrasive layer region 25 Small abrasive layer portion 26 Circumferential abrasive layer portion 30 Super abrasive Grain 31 Metal plating phase (Metal bonding phase) 42 Arc abrasive grain layer part R Synthetic resin layer

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Hanako Hata 246-1 Egoshi, Kurosuno, Izumi-cho, Iwaki-shi, Fukushima F-term in Mitsubishi Materials Corporation Iwaki Works 3C047 EE02 EE11 3C063 AA02 AB05 BA08 BB02 BC02 BG07 CC13 EE26 FF09 FF20

Claims (6)

[Claims] A hollow region in which no abrasive grains are provided is provided at the center of the surface of the grinding wheel base, and an abrasive layer region is provided outside the hollow region. A CMP conditioner comprising a plurality of small abrasive layer portions in which one or a plurality of abrasive grains are fixed with a metal binding phase at intervals. 2. A grinding wheel base, comprising: a hollow region in which no abrasive grains are provided in the center of the surface of the grinding wheel base; and an abrasive grain layer region provided outside the hollow region. A first abrasive grain layer region in which a plurality of small abrasive grain layer portions in which one or more abrasive grains are fixed by a metal bonding phase are provided at intervals, and a plurality of abrasive grains are provided on an outer peripheral side of the first abrasive grain layer region; A CMP conditioner comprising a substantially ring-shaped second abrasive layer layer in which grains are fixed with a metal binding phase. 3. A grinding wheel base, wherein a hollow region where no abrasive grains are provided is provided at the center of the surface of the grinding wheel base, and an abrasive grain layer region is provided outside the hollow region. A first abrasive grain layer region in which a plurality of small abrasive grain layer portions in which one or more abrasive grains are fixed by a metal bonding phase are provided at intervals, and a plurality of abrasive grains are provided on an outer peripheral side of the first abrasive grain layer region; A CMP conditioner characterized in that a substantially arc-shaped abrasive grain layer portion in which grains are fixed by a metal binding phase is constituted by a second abrasive grain layer region arranged in a substantially ring shape through a slit. 4. The CMP conditioner according to claim 2, wherein an outer peripheral side surface of the second abrasive grain layer region is formed in a tapered shape or an arc shape in a longitudinal sectional view. 5. When the outer diameter of the grinding wheel base is D and the radial width of the substantially ring-shaped abrasive grain layer area is W, the width W of the abrasive grain layer area is 10% or less of the outer diameter D. The CMP conditioner according to any one of claims 1 to 4, wherein the CMP conditioner is set in a range of 42%. 6. The CMP conditioner according to claim 1, wherein at least the surface of the hollow region in the grinding wheel base is covered with a synthetic resin layer having water repellency.