JP2000246646A - Electroplated whetstone - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To prevent the sharpening of super-abrasive grains from decreasing and to prevent the metal plating phase from dissolving out in a strongly alkaline or strongly acidic corrosive environment to thereby prevent the super-abrasive grains from falling off. SOLUTION: An electrodeposition coating is applied to a surface of a metal plating phase 15 of an abrasive layer 13 to form an electrodeposition coating film 22 of an acrylic resin. Since the superabrasive grains 14 lack conductivity, the electrodeposition coating film 2
2 is hardly formed, and the electrodeposition coating film 22 is deposited on the surface of the electroplating phase 15.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art As an example of a CMP apparatus (chemical mechanical polishing machine) for chemically and mechanically polishing a surface of a semiconductor wafer (hereinafter, simply referred to as a wafer) cut out of a silicon ingot as shown in FIG. There is a device. Wafers are required to be mirror-polished so as to have a highly accurate and defect-free surface with the miniaturization of devices. 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 alkaline solution, an acidic solution, or the like. As shown in FIG. 5, this CMP apparatus 1 is provided with a polishing pad 4 made of, for example, hard urethane on a disk-shaped rotary table 3 attached to a center shaft 2. 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 holds the wafer 6. The wafer 6 is disposed between the wafer carrier 5 and the pad 4 and used for polishing the surface on the pad 4 side. It is mirror-finished.

At the time of polishing, free abrasive grains made of, for example, the above-mentioned fine-particle silica are used as an abrasive, and a mixture of an oxidizing acidic liquid or the like for etching is supplied onto the pad 4 as a liquid slurry s. As a result, the slurry s flows between the wafer 6 and the pad 4 held by the wafer carrier 5, and the wafer 6 rotates on the wafer carrier 5, and at the same time, the pad 4 rotates about the central axis 2. Therefore, one surface of the wafer 6 is polished by the pad 4. A large 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 with the slurry s held in these foam layers. Will be However, repeated polishing of the wafer 6 causes a problem that the flatness of the polished surface of the pad 4 is reduced and the polishing accuracy of the wafer 6 is reduced.

[0004] For this reason, conventionally, the CMP apparatus 1 shown in FIG.
As shown in FIG. 1, a pad conditioner 8 is provided, and the surface of the pad 4 is polished (conditioned). The pad conditioner 8 includes an electrodeposition wheel 11 provided on a rotating shaft 9 provided outside the rotary table 3 via an arm 10. The arm 10 is rotated by the rotating shaft 9, thereby rotating the pad 4. Above, the surface of the pad 4 is polished by reciprocatingly oscillating the electrodeposition wheel 11 so that the flatness and the like of the surface of the pad 4 can be recovered or maintained. This electrodeposited wheel 11 is shown in FIG.
As shown in FIG. 7, a ring-shaped abrasive layer 13 having a flat upper surface is formed on a circular plate-shaped base metal 12, and the abrasive layer 13 is, for example, as shown in FIG. Super abrasive grains 14 such as diamond and cBN by electroplating
Are dispersed and fixed by the metal plating phase 15. The metal plating phase 15 is made of, for example, nickel.

When such an electrodeposition wheel 11 is used for the pad conditioner 8, the slurry s supplied on the pad 4 for polishing the wafer 6 is largely retained on the pad 4 by a fine foam layer. Since the slurry s is a strongly alkaline or strongly acidic fluid, the metal plating phase 15 is attacked when the pad 4 is polished, and the heavy metal of the metal plating phase 15 dissolves into the slurry s. Occurs. For this reason, there is a drawback that adverse effects such as inhibiting the mirror polishing of the wafer 6 are caused. In addition, since the metal plating phase 15 dissolves into the slurry s, the holding power of the superabrasive grains 14 is reduced, and the superabrasive grains 14 are liable to fall off. There is a disadvantage that the superabrasive grains 14 that have been driven into the pad 4 and fall off during the subsequent polishing of the wafer 6 cause scratches on the wafer 6. On the other hand, a technique has been proposed in which a corrosion-resistant material is coated on the surface of the abrasive grain layer 13 in order to ensure corrosion resistance to a strongly alkaline or strongly acidic slurry s. As shown in FIG. 9, the coating film 16 coats the surface of the abrasive grain layer 13 by using a baking coating method of baking and drying a material such as a fluororesin to form a coating film.
This coating film 16 has high corrosion resistance, for example, 10 μm.
m.

[0006]

However, since the coating film 16 formed by baking is formed not only on the surface of the metal plating phase 15 but also on the surface of the superabrasive grains 14 with the same thickness as the coating film, the grinding process is performed. There is a disadvantage that the sharpness of the superabrasive grains 14 sometimes decreases. SUMMARY OF THE INVENTION In view of such circumstances, an object of the present invention is to provide an electrodeposition whetstone that can surely protect a metal binding phase and ensure corrosion resistance and does not cause a decrease in sharpness.

[0007]

The electrodeposition grindstone according to the present invention is an electrodeposition grindstone in which superabrasive grains are dispersed and arranged in a metal binder phase, wherein the surface of the metal binder phase is coated with an electrodeposition coating film. It is characterized by becoming. When electrodeposition coating (electro permanent coating) is used to deposit a coating of a corrosion-resistant material on the surface of the metal binder phase, which is the surface of the object to be coated on the electrodeposited grindstone, the superabrasive grains lack electrical conductivity and the surface is damaged. The paint is not electrodeposited on the surface, but the paint is electrodeposited only on the surface of the metal binding phase to form an electrodeposition coating film.

[0008] The electrodeposition grinding wheel according to the present invention is an electrodeposition grinding wheel in which superabrasive grains are dispersed and arranged in a metal binding phase, wherein the surface of the metal binding phase is coated with a hard noble metal plating layer. It is characterized by being coated with an electrodeposition coating film on the layer. By coating the surface of the metal binding phase with a hard noble metal plating layer by electroplating, for example, a layer having a Vickers hardness of at least Hv300 is formed, and this hard noble metal plating layer is hardly formed on the surface of the superabrasive grains lacking in electrical conductivity. It is not coated, but is coated on the surface of the metal binding phase to improve wear resistance and corrosion resistance. Furthermore, when a paint of a corrosion resistant material is electrodeposited on the surface by electrodeposition coating (electric permanent coating),
Since the superabrasive grains lack electric conductivity, the surface of the hard noble metal plating layer is hardly electrodeposited with a paint, and the paint is electrodeposited on the surface of the hard noble metal plating layer to form an electrodeposition coating film. Thereby, the sharpness of the superabrasive grains is ensured, and the metal binder phase holding the superabrasive grains is protected by the hard noble metal plating layer and the electrodeposition coating film, so that the corrosion resistance can be improved in two stages.

A ceramic coating layer having electrical conductivity may be provided instead of the hard noble metal plating layer. The ceramic coating layer having electrical conductivity is formed on the surface of the metal bonding phase by PVD or the like, and at that time, the surface of the superabrasive grains is also coated, and the ceramic coating layer on the superabrasive grains is machined by dressing or the like. The coating is electrodeposited only on the surface of the ceramic coating layer by applying a coating such as a corrosion-resistant resin to the surface of the ceramic coating layer by electrodeposition coating (electric permanent coating). An electrodeposition coating is formed. As the ceramic coating layer having electrical conductivity, a non-oxide ceramic such as TiN is particularly preferable because of its high corrosion resistance. The above-mentioned electrodeposition coating film is a corrosion-resistant resin film,
In particular, an acrylic resin film may be used. Acrylic resin is chemically stable, has high corrosion resistance, and has high water resistance, so that it can shut off the corrosive medium in a corrosive environment such as being immersed in slurry s and can reliably prevent corrosion of the metal bonding phase. . In addition, this electrodeposition grindstone may be used as a pad conditioner of a CMP apparatus.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings, and the same or similar parts as those of the above-described prior art will be described using the same reference numerals. FIG. 1 is a longitudinal sectional view of a main part of an electrodeposited wheel according to a first embodiment, FIG.
FIG. 3 is a view showing a method of electrodeposition coating. The electrodeposition wheel according to the embodiment is used by being attached to the arm 10 of the pad conditioner 8 of the CMP apparatus 1 described above. Electrodeposited wheel 2 according to the first embodiment shown in FIG.
0 (electroplated grinding wheel) has the same configuration as the conventional electrodeposited wheel 11 shown in FIGS. 6 to 8 described above. That is, the abrasive layer 13 is provided on the base metal 12, and the abrasive layer 13 is, for example, N
Superabrasive grains 14 such as diamond or cBN are dispersed and arranged in a metal plating phase 15 (metal bonding phase) made of i, and are manufactured by electroless plating or electroplating.

In the electrodeposited wheel 20, the upper portion 14a of the superabrasive 14 is fixed to the metal plating phase 15 so as to protrude.
m of electrodeposition coating film 22 is formed. The electrodeposition coating film 22 is applied by electrodeposition to the surface 15a of the metal plating phase 15 by electrodeposition coating (electric permanent coating).
Is not coated on the upper surface 14a of the electrodeposition coating film 2
2, the upper part 14a of the superabrasive 14 protrudes. The material of the electrodeposition coating film 22 is made of an acrylic resin having high chemical stability and good corrosion resistance.

The electrodeposited wheel 20 according to the present embodiment has the above-described configuration. Next, a method of manufacturing the electrodeposited wheel 20 will be described. First, as shown in FIGS. 6 to 8, an abrasive layer 13 composed of superabrasive grains 14 and a metal plating phase 15 is provided on a base metal 12 by electroplating. Then, electrodeposition coating (electric permanent coating) is performed as shown in FIG. This electrodeposition coating method is, for example, a cationic electrodeposition coating method. For example, a cathode plate 26 is placed in a paint tank 25 filled with a solution 24 of an emulsion resin paint made of an acrylic resin, and the electrodeposition wheel 20 is used as an anode. It is inserted facing the plate 26. The electrodeposition wheel 20 is previously masked except for the surfaces of the superabrasive grains 14 and the metal plating phase 15.

A DC current is passed between the electrodes while circulating and stirring so that the paint concentration in the solution 24 becomes constant,
The negatively charged resin particles in the emulsion resin coating solution 24 move to the surface of the metal plating phase 15 of the electrodeposition wheel 20, which is an anode, and emit and deposit electrons. Then, the water in the deposited coating film moves into the coating solution, and the nearby coating particles become insoluble in water due to the gas generated at the anode electrode to form a coating film. The electrodeposition coating film 22 is formed on the surface of the metal plating phase 15. It is formed. The electrodeposition coating film 22 thus obtained does not precipitate on the superabrasive grains 14 due to the low electrical conductivity of the superabrasive grains 14 whose upper portions 14a protrude from the metal plating phase 15, or is extremely thin. It is only slightly deposited as a film, and adheres to the surface of the metal plating phase 15 having good conductivity with a uniform thickness regardless of the unevenness. Thus, the electrodeposited wheel 20 shown in FIG. 1 is obtained. In the present embodiment, when the surface of the metal plating phase 15 of the electrodeposition wheel 20 is coated by electrodeposition coating, the electrodeposition coating film 22 is formed by cation electrodeposition coating using the electrodeposition wheel 20 as an anode. Instead, the electrodeposition coating film 22 may be formed by anion electrodeposition using the electrodeposition wheel 20 as a cathode. In the case of anionic electrodeposition coating, since a hydrogen gas is generated on the cathode and a pinhole of hydrogen gas may be formed in the electrodeposition coating film, a cationic electrode coating is preferably used.

According to the electrodeposited wheel 20 of the present embodiment, the arm 10 of the pad conditioner 8 shown in FIG.
If it is attached to and condition the pad 4,
Even if the surface of the abrasive layer 13 is immersed in the strongly acidic slurry s that stays on the pad 4, the surface is covered with the electrodeposition coating film 22 having high corrosion resistance. It is not soaked in and does not dissolve. In particular, in the present embodiment, since the coating film is not formed on the superabrasive grains 14 when producing the electrodeposition coating film 22, the sharpness of the superabrasive grains 14 can be ensured. Further, the metal plating phase 15 is also used for polishing.
Does not come into contact with the cutting powder or the surface to be polished.
Wear can be prevented. Therefore, polishing can be performed in a corrosive environment such as a slurry to maintain or recover the parallelism of the pad 4 with good sharpness without impairing the life of the electrodeposited wheel 20. In the above-described embodiment, the slurry s is a strongly acidic fluid, but the electrodeposited wheel 20 according to the embodiment can exhibit corrosion resistance even with a strongly alkaline fluid.

Next, another embodiment of the present invention will be described. The same or similar portions and members as those in the above-described embodiment will be described using the same reference numerals. FIG. 3 is a sectional view of a main part of an electrodeposited wheel according to a second embodiment of the present invention. In the electrodeposited wheel 30 (electroplated whetstone) according to the second embodiment shown in FIG. 3, an abrasive layer 13 is provided on a base metal 12, and the abrasive layer 13 is in a metal plating phase 15 (metal bonding phase). And super-abrasive grains 14 such as diamonds are dispersed and are manufactured by electroless plating or electroplating. The hard noble metal plating layer 31 is formed on the metal plating phase 15. The hard noble metal plating layer 31 is made of, for example, P
It is made of a noble metal such as t, Au or Rh, and has a Vickers hardness of, for example, 300 Hv or more, and a plating thickness of, for example, 0.2 to 5 μm. in this case,
Since the superabrasive grains 14 lack electric conductivity, the hard noble metal plating layer 31 is not formed, and is formed only on the metal plating phase 15. The hard noble metal plating layer 31 has high corrosion resistance and abrasion resistance, suppresses corrosion due to strongly alkaline or strongly acidic slurry s, prevents the metal plating layer 15 from melting, and has high abrasion resistance. The surface of the hard noble metal plating layer 31 is coated with an electrodeposition coating film 32 by electrodeposition coating (electric permanent coating). The electrodeposition coating film 32 is made of a Teflon-based resin such as a fluororesin. The superabrasive 14 is configured such that its upper part 14a is projected and exposed from the electrodeposition coating film 32.

Since the electrodeposited wheel 30 according to the present embodiment is configured as described above,
5 is mounted on the arm 10 of the pad conditioner 8 shown in FIG. 5 to condition the pad 4, so that even if the surface of the abrasive layer 13 is immersed in the strongly acidic slurry Is coated in two layers with the electrodeposition coating film 32 having high corrosion resistance and the hard noble metal plating layer 31, so that the metal plating phase 15 does not come into contact with the slurry s and melt out. Moreover, the hard noble metal plating layer 31 provided on the lower surface of the electrodeposition coating film 32 has high abrasion resistance, and in this respect, the life of the electrodeposition wheel 30 can be improved. In particular, in the present embodiment, the hard noble metal plating layer 31 and the electrodeposition coating film 32 are formed only on the surface of the metal plating phase 15 excluding the superabrasive grains 14 at the time of manufacture,
There is no danger of reducing the sharpness of the sashimi.

Next, a third embodiment of the present invention will be described with reference to FIG. FIG. 4 is a sectional view of a main part of an electrodeposited wheel according to a third embodiment of the present invention. The electrodeposited wheel 40 (electroplated whetstone) according to the third embodiment shown in FIG.
Abrasive layer 13 in which superabrasive grains 14 such as diamond are dispersed and arranged in a metal plating phase 15 (metal bonding phase).
Is provided. Then, a ceramic coating layer 41 having high electrical conductivity with high corrosion resistance and high wear resistance is formed on the metal plating phase 15. The ceramic coating layer 41 having electrical conductivity is made of, for example, non-oxide ceramic such as TiN, and is formed by PVD such as ion plating with a thickness of 0.5 to 10 μm. In this case, since the ceramic coating layer 41 is formed not only on the metal plating phase 15 but also on the surface of the superabrasive grains 14, the superabrasive grains 14 are formed by mechanical means such as dressing or chemical means such as etching after the film is formed. The upper ceramic coating needs to be removed. An electrodeposition coating film 42 is applied on the ceramic coating layer 41 by electrodeposition coating (electric permanent coating). The electrodeposition coating film 42 is made of an acrylic resin. The superabrasive 14 is configured such that its upper part 14a is projected and exposed from the electrodeposition coating film 42.

Also with the electrodeposition wheel 40 according to the present embodiment, since the electrodeposition coating film 42 and the ceramic coating layer 41 do not cover the superabrasive grains 14, the corrosion resistance can be improved without lowering the sharpness. Moreover, since the metal plating phase 15 is covered with the electrodeposition coating film 42 having high corrosion resistance and the ceramic coating layer 41 in two layers, the metal plating phase 15 is not immersed in the slurry s and does not melt out. Moreover, the ceramic coating layer 4
No. 1 has high wear resistance and can improve the life.

The electrodeposition grindstone according to the present invention is not limited to the pad conditioner 8, but can be used for an electrodeposition grindstone which may be used in various corrosive environments.

[0020]

As described above, the electrodeposition grindstone according to the present invention is formed by coating the surface of the metal binding phase with the electrodeposition coating film. Only an electrodeposition coating film can be formed to cover and secure sharpness by superabrasive grains.Also, even when grinding in a strongly alkaline or strongly acidic corrosive environment, the electrodeposition coating film prevents melting of the metal binding phase and improves corrosion resistance This has the effect of improving the grinding wheel life.

The electrodeposited grinding wheel according to the present invention is formed by coating a hard noble metal plating layer on a metal binding phase and coating an electrodeposition coating film on the hard noble metal plating layer. Since the electrodeposition coating film is not coated with the superabrasive grains during its production, sharpness can be ensured. In addition, two coating layers having high corrosion resistance can be formed on the metal plating phase to protect the metal plating phase from a corrosive environment, and the hard noble metal plating layer has high wear resistance, so that the life of the grinding wheel can be further improved. Further, since the ceramic coating layer having electric conductivity is provided instead of the hard noble metal plating layer, the corrosion resistance and the wear resistance can be similarly improved by the two layers.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a main part of an electrodeposited wheel according to a first embodiment of the present invention.

FIG. 2 is an explanatory view showing steps for manufacturing the electrodeposited wheel shown in FIG. 1 by electrodeposition coating.

FIG. 3 is a longitudinal sectional view of a main part of an electrodeposited wheel according to a second embodiment of the present invention.

FIG. 4 is a longitudinal sectional view of a main part of an electrodeposited wheel according to a third embodiment of the present invention.

FIG. 5 is a perspective view showing a main configuration of a general CMP apparatus.

FIG. 6 is a plan view of a conventional electrodeposition wheel used in the CMP apparatus shown in FIG.

FIG. 7 is a central longitudinal sectional view of the electrodeposited wheel shown in FIG. 6;

8 is an enlarged sectional view of a main part of an abrasive layer of the electrodeposition wheel shown in FIG.

9 is a cross-sectional view of a main part showing a state where a coating film is formed on an abrasive layer of the electrodeposition wheel shown in FIG. 8;

[Explanation of symbols]

 13 Abrasive layer 14 Super abrasive 15 Metal plating phase 20, 30, 40 Electroplated wheel 22, 32, 42 Electroplated coating film 31 Hard noble metal plating layer 41 Ceramic coating layer

Claims (3)

[Claims] 1. An electrodeposition grindstone in which superabrasive grains are dispersed and arranged in a metal binding phase, wherein the surface of the metal binding phase is coated with an electrodeposition coating film. 2. An electrodeposition grindstone in which superabrasive grains are dispersed and arranged in a metal binding phase, wherein a surface of the metal binding phase is coated with a hard noble metal plating layer, and an electrodeposition coating film is formed on the hard noble metal plating layer. An electrodeposited whetstone characterized by being coated with. 3. The electrodeposited grinding wheel according to claim 2, wherein a ceramic coating layer having electrical conductivity is provided in place of said hard noble metal plating layer.