JP2001315062A - Electrodeposition grinding wheel and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrodeposition grinding wheel with high polishing efficiency and hardly causing clogging. SOLUTION: A coating layer 32 is formed on a base metal 12. A plurality of through-holes 33 reaching from a surface of the coating layer 32 to a surface of the base metal 12 are formed in the coating layer 32. Metal plating phases 34 are formed individually per each through-hole 33 on the surface of the base metal 12 through the through-holes 33, and super abrasive grains 14 are fixed to the base metal 12 by these metal plating phases 34.

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 Conventionally, for example, a semiconductor wafer cut from a silicon ingot (hereinafter simply referred to as a wafer)
As an example of a CMP apparatus (chemical mechanical polishing machine) for chemically and mechanically polishing the surface of a semiconductor device, there is an apparatus as shown in FIG. Wafers are required to be mirror-polished so as to have a highly accurate and defect-free surface with miniaturization of devices. The mechanism of polishing by the CMP apparatus 1 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. In the 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 rotatable wafer carrier 5 is provided at a position eccentric from the center axis 2 of the pad 4. The wafer carrier 5 has a disc shape smaller in diameter than the pad 4 and holds the wafer 6, and the wafer 6 is disposed between the wafer carrier 5 and the pad 4 and is used for polishing the surface on the pad 4 side. Mirror finish.

In polishing, for example, the above-mentioned free abrasive grains made of fine-particle silica or the like are used as an abrasive, and a mixture of an alkaline solution for etching and the like is supplied onto the pad 4 as a liquid slurry S. Therefore, the slurry S is supplied to the wafer 6 held on the wafer carrier 5.
The wafer 6 held by the wafer carrier 5 rotates between the pad 4 and the pad 4, and at the same time, the pad 4 rotates about the central axis 2 so that the wafer 6
Is polished. 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 polishing of the wafer 6 is performed by the slurry S held in these foam layers. Will be However, since the flatness of the polished surface of the pad 4 is reduced or clogged by repeating the polishing of the wafer 6, a problem arises that polishing accuracy and polishing efficiency of the wafer 6 are reduced.

For this reason, conventionally, the CMP apparatus 1 has
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 to recover or maintain the flatness or the like of the surface of the pad 4 and eliminate clogging. As shown in FIGS. 4A and 4B, the electrodeposited wheel 11 has a ring-shaped abrasive layer 13 formed on a disk-shaped base metal 12 having a flat upper surface and a constant width. The abrasive layer 13
For example, as shown in FIG. 5, a superabrasive 14 such as diamond or cBN is dispersed and fixed in a metal plating phase 15 on a base metal 12 by electroplating or the like. The metal plating phase 15 is made of, for example, nickel. Note that grooves 17 are formed in the surface of the abrasive grain layer 13 at predetermined intervals of, for example, 45 ° in the radial direction, and the slurry S and chips are discharged to the outside through the grooves 17.

[0005]

When the pad 4 is polished using such an electrodeposition wheel 11,
By repeatedly polishing the pad 4, shavings of the resin of the pad 4 and the altered slurry S adhere to and accumulate on the surface of the metal plating phase 15 between the superabrasive grains 14, thereby causing clogging. In such a case, the polishing efficiency of the pad 4 is reduced. Therefore, the electrodeposition wheel 11 is replaced with a new one, or the electrodeposition wheel 11 is washed to remove the clogging. I was

Therefore, the electrodeposition wheel 11 has been improved to
A device that does not easily cause clogging has been devised. As shown in FIG. 6, the electrodeposited wheel 18 is different from the conventional electrodeposited wheel 11 in that a material having a small coefficient of friction such as fluororesin is applied to the surface of the abrasive layer 13.
This makes it difficult for the shavings of the pad 4 and the deteriorated slurry S to adhere between the superabrasive grains 14. However, in this electrodeposited wheel 18, the super-abrasive particles 14
Is further coated on the metal plating phase 15 to which
Is provided, the protrusion amount H1 of the superabrasive grains 14 with respect to the surface of the coating layer 19 is reduced. For this reason, the electrodeposition wheel 18
And the polishing efficiency of the pad 4 is low. further,
When a fluororesin is used for the coating layer 19, the fluororesin cannot be directly adhered on the metal plating phase 15, and the fluororesin phase 21 is formed after the base phase 20 such as a resin is laminated on the metal plating phase 15. In this case, the thickness of the coating layer 19 increases, and the protrusion amount H of the superabrasive grains 14 increases.
1 becomes smaller. Therefore, in order to increase the projection amount H1 of the superabrasive grains 14 with respect to the surface of the coating layer 19, the projection amount H2 of the superabrasive grains 14 from the surface of the metal plating phase 15 is set.
When the ratio is increased, the force for fixing the superabrasive grains 14 to the metal plating phase 15 is reduced, and the superabrasive grains 14 are likely to fall off.

Further, when the coating layer 19 is formed on the metal plating phase 15, the surface of the superabrasive grains 14 is also covered by the coating layer 19, so that the sharpness of the electrodeposition wheel 18 is low in this state. Therefore, after forming the covering layer 19, the covering layer 19 is formed.
The portion covering the super-abrasive grains 14 is scraped off in
However, at this time, the surface of the superabrasive grains 14 is also shaved and the corners are rounded, so that the sharpness of the electrodeposition wheel 18 is low and the polishing efficiency of the pad 4 is low.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide an electrodeposition whetstone which is less likely to cause clogging and has a high polishing efficiency.

[0009]

According to a first aspect of the present invention, there is provided an electrodeposition grindstone having a plurality of through-holes on a surface of a base metal, the through-holes covering the surface and communicating from the surface of the base metal to the surface of the base metal. A non-conductive coating layer is formed, and a metal plating phase is formed on the surface of the base metal through the through holes independently for each through hole of the coating layer. Are fixed.

In the electrodeposited grinding wheel constructed as described above, the coating layer is formed directly on the base metal, not on the metal plating phase. Surface recedes toward the surface of the base metal by the thickness of the metal plating phase. This makes it possible to form a coating layer between each abrasive grain layer and the pad to prevent the adhesion of resin shavings and slurry to the surface of the electrodeposited grinding wheel (coating layer) as compared to a conventional electrodeposited wheel having a coating layer. Of the superabrasive grains from the surface of the metal plating phase or the surface of the metal plating phase that protrudes most from the base metal) can be increased. In addition, the amount of the superabrasive particles protruding from the surface of the metal plating phase can be suppressed while ensuring the amount of the superabrasive particles protruding from the surface of the electrodeposited whetstone.
Here, the thickness of the metal plating phase may be equal to or greater than the thickness of the coating layer. In this case, regardless of the thickness of the coating layer, the protruding amount of the superabrasive grains from the surface of the electrodeposition grindstone can be secured. Also, if the thickness of the metal plating phase is sufficiently large in this way, the thickness of the coating layer can be increased while ensuring the amount of projection of the superabrasive grains from the surface of the electrodeposited whetstone,
The durability of the coating layer can be improved. Here, the superabrasive grains may be fixed to the abrasive layer in each through hole formed on the base metal one by one, or a plurality of superabrasive grains may be fixed. For the coating layer, a material having a smaller friction coefficient than the metal plating phase, for example, a fluororesin, ceramic, titanium nitride, titanium carbide, or the like is used.

According to a second aspect of the present invention, a non-conductive coating layer is formed on the surface of the base metal, and a plurality of through holes are formed in the coating layer from the surface to the surface of the base metal. An abrasive layer in which superabrasive grains are fixed in a metal plating phase on the surface of the base metal through the through holes is formed independently for each of the through holes. In the electrodeposited grinding wheel configured as described above, the coating layer is formed directly on the base metal, not on the metal plating phase, so that there is no adhesion of resin shavings or slurry of the pad between the respective abrasive grain layers. The amount of superabrasive particles protruding from the surface of the electrodeposited grindstone can be increased as compared to a conventional electrodeposited wheel having a coating layer, while forming a coating layer to prevent. In addition, the amount of the superabrasive particles protruding from the surface of the metal plating phase can be suppressed while ensuring the amount of the superabrasive particles protruding from the surface of the electrodeposited whetstone. Further, if the thickness of the metal plating phase is sufficiently large, the thickness of the coating layer can be increased while ensuring the projection amount of the superabrasive grains, and the durability of the coating layer can be improved. And unlike the electrodeposited wheel having the conventional coating layer, since it is not necessary to perform the work of peeling the coating layer made of a fluororesin or the like from the superabrasive grains, the production which cannot be avoided in the electrodeposited wheel having the conventional coating layer A decrease in sharpness at a stage can be avoided.

According to a third aspect of the present invention, there is provided a method for manufacturing an electrodeposited grindstone, wherein a non-conductive coating layer is formed on a surface of a base metal, and a through hole extending from the surface to the surface of the base metal is formed in the coating layer. A plurality of layers are formed, electroplating is performed on the surface of the base metal using the coating layer as a mask, super-abrasive grains are fixed to the surface of the base metal by a metal plating phase, and the abrasive grains are independently formed for each of the through holes. Forming a layer. In the method of manufacturing the electrodeposited whetstone, a non-conductive material is used for the coating layer, and the coating layer is used as a mask when electrodepositing the superabrasive grains, so that a target portion, that is, a through hole is formed. The metal plating phase is formed only in the portion where the super-abrasive grains are formed independently for each through-hole, thereby forming an abrasive grain layer in which super-abrasive grains are independently fixed. Thus, the electrodeposited grinding wheel according to claim 1 or 2 can be easily manufactured. Here, each metal plating phase may be formed by one or more plating processes. In this case, the type of metal to be plated may be changed for each plating process.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the accompanying drawings. FIG.
FIG. 2 is a partial vertical sectional view showing a main part of the electrodeposited wheel of the present embodiment. The electrodeposited wheel 31 (electroplated whetstone) of the present embodiment has a disk-shaped base metal 12 like the conventional electrodeposited wheel 11. The base metal 12 is made of a corrosion-resistant material such as stainless steel. The base metal 12 has, for example, an abrasive layer 13 in a conventional electrodeposition wheel 11.
Similarly to the above, the upper surface has a planar shape, and the coating layer 32 is formed with a constant thickness.

The coating layer 32 prevents the resin shavings and slurry S of the pad 4 from adhering to the surface of the base metal 12 and has a smaller friction coefficient than at least a metal plating phase 34 described later. A non-conductive material is used. In the present embodiment, a fluororesin is used for the coating layer 32. Since the fluororesin cannot be directly attached to the surface of the metal base 12, the coating layer 32 is provided with a base phase 20 made of a resin or the like on the surface of the base 12, and the fluororesin phase 21 is formed thereon. Is provided.
In this case, the thickness D2 of the base phase 20 is 30 μm or less, and the thickness D3 of the fluororesin phase 21 is 20 to 200 μm. When ceramic, titanium nitride, titanium carbide, or the like is used for the coating layer 32,
Since these can be directly attached to the base metal 12 by, for example, a sputtering method or other commonly used means, a base phase is unnecessary. In this case, the thickness of the coating layer 32 is about several μm. As shown in FIG. 1, a plurality of through holes 33 extending from the surface of the coating layer 32 to the surface of the base metal 12 are formed at predetermined intervals in the coating layer 32.

Further, each through hole 3 is formed in the electrodeposition wheel 31.
Each metal plating phase 34 is formed on the surface of the base metal 12 through the through hole 33 independently for each metal plating phase 3.
4 form an abrasive layer 35 to which superabrasives 14 such as diamond and cBN are fixed. Metal plating phase 34
Is made of, for example, Ni or the like, like the metal plating phase 15 of the conventional electrodeposited wheel, and is formed by electroplating or the like. In the present embodiment, the thickness D1 of the metal plating phase 34 is equal to the thickness (D2 +
The thickness is almost the same as D3). In addition, super abrasive 14
Is in the range of, for example, 80 to 200 μm.

The through hole 33 formed in the coating layer 32 is formed in a round hole shape by, for example, drilling with a mini drilling machine or the like (the shape of the through hole 33 can be arbitrary). In this case, the diameter of the through hole 33 is in the range of 0.5 to 3 mm. Here, if the diameter of the through-holes 33 is too small, the area of the metal plating phase 34 formed in each of the through-holes 33 becomes small, the adhesion strength to the base metal 12 decreases, and the superabrasive grains 14 may fall off. If the diameter of the through-hole 33 is too large, the area of the metal plating phase 34 becomes large and the superabrasive grains 14 are densely arranged, so that clogging between the superabrasive grains 14 occurs. It will be easier. In the coating layer 32, the through holes 33 may be provided in a regular arrangement such as, for example, arranged in a substantially lattice shape, or may be provided in an irregular arrangement.
In the coating layer 32, the ratio of the total opening area of the through holes 33 to the total area of the coating layer 32 in a plan view of the electrodeposition wheel 31 is in the range of 10 to 80%. If this ratio is too small, the area of the portion (abrasive layer) that acts on the polishing of the pad 4 will be small, and the polishing efficiency will decrease. If this ratio is too large, the density of these superabrasive grains 14 will increase, and Clogging may occur between the abrasive grains 14.

The electrodeposited wheel 31 according to the present embodiment is configured as described above. Next, a method of manufacturing the electrodeposited wheel 31 will be described with reference to FIG. In FIG. 2A, for example, a disk-shaped base 12 made of SUS304 or the like is used.
The base phase 20 is formed in a ring shape with a constant width on the upper surface of the substrate.
Then, a fluororesin is applied on the upper surface of the base phase 20 to form a fluororesin phase 21, and the covering layer 32 is formed by the base phase 20 and the fluororesin phase 21 (see FIG. 2B). Next, as shown in FIG. 2C, a plurality of through holes 33 are formed in the coating layer 32 from the surface to the surface of the base metal 12 using a mini drilling machine or the like. Here, the arrangement of the through holes 33 in the coating layer 32 can be arbitrary. When forming the through-hole 33, the surface of the base metal 12 may be shaved together with the coating layer 32. Then, the upper surface of the base metal 12 is subjected to electroplating from above the coating layer 32, and the superabrasive grains 14 are fixed to the surface of the base metal 12 by the metal plating phase 34 to form the abrasive layer 35. Here, the coating layer 32 has non-conductivity and serves as a mask for electroplating.
3 and an independent metal plating phase 34 is formed for each through hole 33 (see FIG. 2D). Here, each metal plating phase 34 may be formed by one or more plating processes. In this case, the type of metal to be plated may be changed for each plating process. As described above, in the method for manufacturing the electrodeposited wheel of the present embodiment, the metal plating 1 is applied through the through holes 33 formed in the coating layer 32 by performing electroplating using the coating layer 32 as a mask.
Since the superabrasive grains 14 can be electrodeposited on the second electrode 2 in a predetermined arrangement, the electrodeposition wheel 31 can be easily formed.

The electrodeposition wheel 31 according to the present embodiment has the above-described configuration, and the pad 4 is mounted on the arm 10 of the CMP apparatus 1 shown in FIG.
In performing the conditioning, the electrodeposition wheel 31 is reciprocatedly oscillated by swinging the arm 10 with respect to the pad 4 on the rotating rotary table 3, and the pad 4 is ground to recover or maintain its flatness. .

As described above, in the electrodeposited wheel 31 according to the present embodiment, since the coating layer 32 is formed directly on the base metal 12 instead of on the metal plating phase 34,
Compared with the conventional electrodeposited wheel 18 having a coating layer, the surface of the coating layer 32 is
2 retreats to the surface side. As a result, the coating layer 32 is formed between the abrasive layers 35 to remove resin shavings and slurry S of the pad 4.
The surface of the electrodeposited wheel 31 (coating layer 3
The protruding amount of the superabrasive grains 14 with respect to the surface 2 or the surface of the metal plating phase 34 (the surface most protruding from the base metal 12) can be increased to improve the sharpness of the electrodeposition wheel 31. In addition, the amount of protrusion of the superabrasive particles 14 from the surface of the metal plating phase 34 can be suppressed while ensuring the amount of protrusion of the superabrasive particles 14 from the surface of the electrodeposition wheel 31, and It can be firmly fixed to the phase 34. Also, if the thickness D1 of the metal plating phase 34 is sufficiently large, the thickness of the coating layer 32 can be increased while ensuring the amount of projection of the superabrasive grains 14 from the surface of the electrodeposited wheel 31,
The durability of the coating layer 32 can be improved. Further, unlike the electrodeposited wheel 18 having the conventional coating layer, the operation of peeling the coating layer 32 from the superabrasive grains 14 is not required, so that the sharpness in the manufacturing stage which cannot be avoided with the conventional electrodeposited wheel 18 is reduced. Can be avoided.

As described above, according to the electrodeposited wheel 31 of the present embodiment, clogging hardly occurs and the pad 4
Polishing efficiency can be improved. Also, the abrasive layer 3
5 can be prevented from falling off. Furthermore, the durability of the electrodeposited wheel 31 can be improved by increasing the thickness of the coating layer 32, and the life of the electrodeposited wheel 31 can be improved.

In the above embodiment, the coating layer 32
May be formed on the entire upper surface of the base 12, and the base 1
2, or any other shape. In this case, as a matter of course, the metal plating phase 34 and the superabrasive grains 14 fixed to the metal plating phase 34 are also dispersed and arranged over the coating layer 32. Further, in the above-described embodiment, an example in which the metal plating phase 34 has the same thickness as the coating layer 32 has been described. However, without being limited to this, the metal plating phase 34 thicker than the coating layer 32 may be used. Then, the superabrasive grains 14 may be fixed at positions protruding from the upper surface of the coating layer 32 by the metal plating phase 34. In such an electrodeposited wheel, for example, a coating layer 32 is formed on the base metal 12 in the same manner as in the method of manufacturing the electrodeposited wheel 31, and a through-hole 33 is formed in the coating layer 32. A metal plating process is performed to form a base metal plating phase, and metal plating is further performed on the base metal plating phase to form superabrasive grains 14.
To form an abrasive layer fixed by the upper metal plating phase formed on the underlying metal plating phase. By configuring the electrodeposition wheel in this way, regardless of the thickness of the coating layer 32,
The protrusion amount of the superabrasive grains 14 can be secured, the sharpness of the electrodeposition wheel 41 can be improved, and the polishing efficiency of the pad 4 can be improved.

[0022]

According to the present invention, the following effects can be obtained.
According to the electrodeposited grindstone of claim 1, the surface of the electrodeposited grindstone is formed while preventing the clogging from being caused by forming a coating layer for preventing the adhesion of shavings and slurry of the resin of the pad between the respective abrasive grain layers. The projection amount of the superabrasive grains with respect to the diameter is increased, the sharpness of the electrodeposition grindstone is improved, and the polishing efficiency can be improved. In addition, since the superabrasive grains can be firmly fixed to the metal plating phase, the dropout of the superabrasive grains can be reduced. Also,
By increasing the thickness of the coating layer, the strength of the coating layer can be improved, and the life of the electrodeposition grindstone can be improved.

According to the electrodeposited grinding wheel of the second aspect, a coating layer is formed between each abrasive grain layer to make clogging less likely to occur.
It is possible to avoid a decrease in sharpness at the manufacturing stage, which cannot be avoided with an electrodeposited wheel having a conventional coating layer, and it is possible to improve polishing efficiency.

According to the method for manufacturing an electrodeposited grinding wheel of the third aspect, the electrodeposited grinding wheel of the first or second aspect, in which clogging is unlikely to occur and which has a high polishing efficiency, can be easily manufactured.

[Brief description of the drawings]

FIG. 1 is a partial longitudinal sectional view showing a structure of an electrodeposited wheel (electroplated whetstone) according to an embodiment of the present invention.

FIG. 2 is a view showing a manufacturing process of the electrodeposited wheel according to the embodiment of the present invention.

FIG. 3 is a perspective view of a main part of a conventional CMP apparatus.

4A is a partial plan view of the electrodeposited wheel shown in FIG. 3, and FIG. 4B is a sectional view taken along line AA ′ of FIG.

FIG. 5 is a partial longitudinal sectional view of the abrasive grain layer shown in FIG.

FIG. 6 is a partial longitudinal sectional view showing another configuration of a conventional electrodeposition wheel.

[Explanation of symbols]

 12 base metal 14 superabrasive grain 31 electrodeposited whetstone 32 coating layer 33 through hole 34 metal plating phase 35 abrasive grain layer

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) B24D 7/02 B24D 7/02 B // H01L 21/304 622 H01L 21/304 622M (72) Inventor Hanako Hata Fukushima Prefecture 246-1 Egoshi, Kurosuno, Izumi-cho, Iwaki F-term (reference) in Mitsubishi Materials Corporation Iwaki Works 3C047 EE18 EE19 3C058 AA07 AA19 CB01 CB03 DA17 3C063 AA02 AB05 BA02 BB02 BB23 BC02 BG01 BG07 BG24 CC12 EE10 FF20FF22

Claims (3)

[Claims] 1. A non-conductive coating layer is formed on a surface of a base metal and is provided with a plurality of through-holes covering the surface and extending from the surface of the base metal to the surface of the base metal. An electrodeposited whetstone, wherein a metal plating phase is formed on the surface of the base metal independently for each hole, and superabrasive grains are fixed to the metal plating phase. 2. A non-conductive coating layer is formed on the surface of the base metal, and a plurality of through holes are formed in the coating layer from the surface to the surface of the base metal. An electrodeposited whetstone, wherein an abrasive grain layer in which superabrasive grains are fixed in a metal plating phase is formed on the surface of the base metal. 3. A non-conductive coating layer is formed on the surface of the base metal, a plurality of through holes are formed in the coating layer from the surface to the surface of the base metal, and the base is formed using the coating layer as a mask. Electroplating whetstone, wherein electroplating is performed on the surface of gold, superabrasive grains are fixed to the surface of the base metal by a metal plating phase, and an abrasive layer is formed independently for each of the through holes. Manufacturing method.