JP2010264567A - Pad conditioner - Google Patents

Abstract

An object of the present invention is to provide a pad conditioner that maintains the flatness of the pad by scraping the surface of the pad and has a long product life while the abrasive grains of the conditioner follow the deformation of the pad. .
A pad conditioner according to the present invention includes an abrasive base having an abrasive surface for abutting against the pad for polishing, a disc-shaped base for supporting the abrasive base, and a disc-shaped base. An outer elastic member disposed on the outer periphery between the gold and the abrasive grain base and formed in an annular shape.
[Selection] Figure 2

Description

  The present invention relates to a pad conditioner for polishing a pad in a CMP (Chemical Mechanical Polishing) apparatus for polishing a semiconductor wafer or the like.

  Various pad conditioners in this type of CMP polishing apparatus have been proposed in which abrasive grains are fixed to a base metal such as stainless steel by a metal plating bonding layer such as nickel. In such a CMP polishing apparatus, when the pad is polished, such a pad conditioner is pressed against the surface of the pad. When the pad conditioner is pressed against the surface of the pad, as the pad surface is elastically deformed, the pad conditioner is placed near the outer periphery of the pad conditioner compared to the abrasive grains placed in the center of the pad conditioner. The surface of the pad is polished with a large pressure applied by the abrasive grains. That is, since a larger pressure concentrates on the abrasive grains arranged in the vicinity of the outer peripheral portion, the abrasive grains in the vicinity of the outer peripheral portion are likely to be locally worn. As a result, the conventional pad conditioner has the disadvantage of shortening the product life.

  Patent Document 1 discloses a pad conditioner that has a lower surface that is convex and has a curved surface on the outer periphery. Patent Document 2 discloses a pad conditioner in which the height of a plurality of abrasive grains arranged on the abrasive grain base is the highest at the center of the base. These pad conditioners prevent the pressure from concentrating on the abrasive grains arranged near the outer periphery of the pad conditioner when polishing the surface of the pad, and the abrasive grains near the outer periphery wear out in a short period of time. Can be prevented.

  Patent Document 3 includes an abrasive base having an abrasive surface, a base that supports the abrasive base, and an elastic member disposed over the entire surface between the abrasive base and the base. A pad conditioner is provided. With this configuration, the pad conditioner can be elastically deformed when the surface of the pad is polished, and can freely follow the surface of the pad.

Japanese Patent No. 3268737 Special table 2008-515238 gazette JP 2003-145424 A

  However, since the pad conditioners described in Patent Document 1 and Patent Document 2 have a constant shape, that is, do not elastically deform, the surface of the pad can be flattened, but the pad conditioner and pad It is not possible to follow the elastic deformation of the pad surface which changes depending on the rotational speed of the pad or the position of the pad conditioner on the pad surface.

  Moreover, since the pad conditioner described in Patent Document 3 has an elastic member disposed over the entire surface between the abrasive grain base and the base metal, it follows the surface of the elastically deformed pad. It is possible to cut the surface of the pad flat.

  The present invention has been made in view of such circumstances, and while maintaining the flatness of the pad by scraping the surface of the pad, preventing the abrasive grains on the outer periphery from being worn out early, An object of the present invention is to provide a pad conditioner capable of extending the service life.

In order to solve the above problems, the present invention proposes the following means.
That is, the pad conditioner according to the present invention includes an abrasive base having an abrasive surface for abutting against the pad for polishing, a disk-shaped base metal that supports the abrasive base, and the disk-shaped base metal And an outer elastic member disposed in an outer peripheral portion between the abrasive grain base and an annular shape.
The pad conditioner is disposed on the outer peripheral portion between the disk-shaped base metal and the abrasive grain base, and includes an outer elastic member formed in an annular shape, so that the pad conditioner can be used when polishing the pad. Is deformed so as to warp upward, and the abrasive grains near the outer periphery of the pad conditioner follow the elastic deformation of the surface of the pad.

The pad conditioner according to the present invention may include a flat region in which the disk-shaped base metal and the abrasive base are directly joined.
Since the disk-shaped base metal and the abrasive grain base include a flat region directly bonded, the surface of the pad can be cut flat.

In the pad conditioner according to the present invention, the thickness dimension of the outer elastic member may be increased from the inner side in the radial direction toward the outer side.
Since the thickness dimension of the outer elastic member increases from the inner side to the outer side in the radial direction, when the pad conditioner is pressed against the surface of the pad, the elastic member is provided in the vicinity of the outer edge where pressure is most concentrated. The amount of deformation due to becomes the largest.

The pad conditioner according to the present invention may include an inner elastic member disposed inside the outer elastic member, and an elastic modulus of the outer elastic member may be set lower than an elastic modulus of the inner elastic member. .
Since the elastic modulus of the outer elastic member is set lower than the elastic modulus of the inner elastic member, the pad conditioner can include a central portion having a high elastic modulus and an outer peripheral portion having a low elastic modulus, It is possible to follow the elastic deformation of the surface of the pad at the outer peripheral portion while cutting the surface of the pad flat at the central portion.

In the pad conditioner according to the present invention, the width of the outer elastic member in the radial direction may be in the range of 1/6 to 1/3 of the diameter of the disk-shaped base metal.
Since the radial width dimension of the outer elastic member is in the range of 1/6 to 1/3 of the diameter of the disk-shaped base metal, the pad conditioner has a flat central portion with an appropriate area, And an elastically deformable outer peripheral portion having a large area.

In the pad conditioner according to the present invention, the maximum deformation amount of the pad conditioner may be in the range of 40 μm to 200 μm.
Since the maximum deformation amount of the pad conditioner is in the range of 40 μm to 200 μm, it is possible to deal with a pad that is relatively easily elastically deformed.

According to the pad conditioner of the present invention, an abrasive base having an abrasive surface for abutting against the pad for polishing, a disk-shaped base metal that supports the abrasive base, and the disk-shaped base metal Since the outer elastic member is disposed on the outer peripheral portion between the abrasive base and the outer elastic member, the pad conditioner of the present invention can cut the surface of the pad flatly.
Further, with the above configuration, the pad conditioner of the present invention can follow the elastic deformation on the surface of the pad, and the abrasive grains on the abrasive grain surface of the abrasive base are always attracted to the pad without the pressure being concentrated locally. The surface can be contacted.

It is the schematic of CMP polishing apparatus provided with the pad conditioner of this invention. It is sectional drawing of the pad conditioner of the 1st Embodiment of this invention. It is sectional drawing of the pad conditioner of the 1st Embodiment of this invention. It is sectional drawing of the pad conditioner of the 2nd Embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described in detail.

As shown in FIG. 1, the CMP polishing apparatus 1 includes a rotary table 3, a wafer carrier 5, and a conditioner mechanism 8 as main components.
The turntable 3 is formed in a disc shape, and a central shaft 2 is attached to the center of the lower surface, and a polishing pad 4 made of, for example, hard urethane is provided on the upper surface. The turntable 3 can be rotated by, for example, a motor (not shown) through the central shaft 2.
The wafer carrier 5 is disposed so as to be able to rotate at a position opposed to the pad 4 and eccentric from the central axis 2 of the pad 4, and a wafer 6 having a disk shape smaller in diameter than the pad 4 is provided on the lower surface thereof. Is held. The lower surface of the wafer 6 is in contact with the surface of the pad 4.
The conditioner mechanism 8 includes a rotating shaft 9, an arm 10, and a pad conditioner 11 as main components. The rotary shaft 9 is rotatably provided outside the rotary table 3 and is connected to one end of the arm 10. The other end of the arm 10 is rotatably connected to the pad conditioner 11.
In FIG. 1, the slurry s is supplied to the upper surface of the pad 4 when the wafer 6 is polished. This slurry s is obtained by using loose abrasive grains made of fine-particle silica or the like as an abrasive and further mixing an alkali solution for etching.

As shown in FIG. 2, the pad conditioner 11 includes a disk-shaped base metal 20, an outer elastic member 30, and an abrasive grain base 40 as main components.
The disc-shaped base metal 20 is formed in a substantially disc shape, and includes a flat upper surface and a lower surface having a flat region 21 and an inclined region 22. The flat region 21 is provided at the center of the lower surface of the disk-shaped base metal 20, and the inclined region 22 is formed between the flat region 21 and its outer edge.
As shown in FIG. 1, the other end of the arm 10 is rotatably connected to the center of the upper surface of the disk-shaped base metal 20. The other end of the arm 10 connects the pad conditioner 11 to the pad 4. Is configured to transmit a pressing force F (shown in FIG. 3) that presses against the surface of the pad and a rotational force for rotating the pad conditioner 11.
Further, the outer elastic member 30 is fixed to the inclined region 22 on the lower surface of the disk-shaped base metal 20 with an adhesive tape or an adhesive, and the abrasive base 40 is formed in the flat region 21 at the center of the lower surface. It is fixed with an adhesive tape or an adhesive.
The disk-shaped base metal 20 may be a machined metal such as stainless steel or may be a machined resin.

The outer elastic member 30 has the same diameter as the disk-shaped base metal 20 and is formed in an annular shape, and the radial cross section of the outer elastic member 30 has a thickness from the inner side toward the outer side in the radial direction. It is formed in a substantially triangular shape so that the size becomes large. The upper surface of the outer elastic member 30 is formed so as to coincide with the inclined region 22 of the disk-shaped base metal 20 and is fixed to the inclined region 22 of the disk-shaped base metal 20 with an adhesive tape or an adhesive. . The lower surface of the outer elastic member 30 has a flat shape and is fixed to the upper surface of the abrasive grain base 40 with an adhesive tape or an adhesive.
The outer elastic member 30 is made of an elastic material such as silicon rubber, and the width L of the outer elastic member 30 is in the range of 1/6 to 1/3 of the diameter of the disk-shaped base metal 20. preferable. When the width L of the outer elastic member 30 is 1/6 or less of the diameter of the disk-shaped base metal 20, a sufficient area for elastic deformation cannot be provided in the outer peripheral portion where the pressure is concentrated. Further, when the width L of the outer elastic member 30 is not less than 1/3 of the diameter of the disk-shaped base metal 20, the pad conditioner 11 cannot secure a flat central portion having a sufficient area.
In the present embodiment shown in FIG. 2, the upper surface of the outer elastic member 30 is formed as an inclined surface so as to coincide with the inclined region 22 that is an inclined surface, but the inclined region 22 in the disk-shaped base metal 20. May be formed as a curved surface so as to coincide with the curved surface. In the present embodiment shown in FIG. 2, the outer elastic member 30 has a substantially triangular cross section, but the outer elastic member 30 may have a tapered shape or a stepped shape. May be. In that case, the inclined region 22 of the disk-shaped base metal 20 is formed so as to coincide with the upper surface of the outer elastic member 30.
Further, in order to improve the bonding strength between the disk-shaped base metal 20 and the outer elastic member 30 and perform alignment, one of the lower surface of the disk-shaped base metal 20 and the upper surface of the outer elastic member 30 has a diameter. A groove formed in a direction may be provided, and a protrusion for engaging with the groove may be provided on the other side.

The abrasive grain base 40 includes a base part 41 fixed to the disc-shaped base metal 20 and the outer elastic member 30, a plurality of abrasive grains 42 disposed on the base part 41, and the abrasive grains 42 on the base part 41. And an adhesive layer 43 for bonding.
The base portion 41 has a substantially disk shape and is formed by metal plating such as nickel plating. The upper surface of the base portion 41 is fixed to the flat region 21 of the disk-shaped base metal 20 and the lower surface of the outer elastic member 30 with an adhesive tape or an adhesive, and the adhesive layer 41 is attached to the lower surface of the base portion 41. A plurality of abrasive grains 42 are bonded to each other.
The plurality of abrasive grains 42 are superabrasive grains such as diamond and cBN. The plurality of abrasive grains 42 are distributed and arranged on the base portion 41 according to a predetermined pattern. The predetermined pattern may be a uniform dispersed pattern or a lattice pattern, or may be a pattern in which dense regions and rough regions are randomly formed.
The adhesive layer 43 fixes the plurality of abrasive grains 42 and the base portion 41, and is formed by metal plating such as nickel plating similarly to the base portion 41.

Below, an example of the dimension which implements this invention is described.
When the diameter of the pad conditioner 11 is 108 mm, the thickness of the base portion 41 is in the range of about 80 μm to about 100 μm. In this case, the grain size of the plurality of abrasive grains 42 is # 100, and the thickness dimension of the adhesive layer 43 is about 110 μm.
In said structure, it is preferable that the maximum displacement in the outer side elastic member 30 is the range of 40 micrometers-200 micrometers. When the maximum displacement in the outer elastic member 30 is 40 μm or less, it becomes difficult for the outer elastic member 30 to follow the elastic deformation on the surface of the pad.

Next, a method for polishing the pad 4 by the pad conditioner 11 of the present embodiment will be described.
In the CMP polishing apparatus 1 shown in FIG. 1, the polishing accuracy of the wafer 6 is reduced because the flatness of the polishing surface of the pad 4, that is, the surface of the pad 4 is reduced or clogged by repeating the polishing of the wafer 6. In addition, the polishing efficiency decreases. When the pad 4 is in such a state, the pad conditioner 11 needs to regrind (condition) the surface of the pad 4.
Therefore, as shown in FIG. 3, the pad conditioner 11 is pressed against the surface of the pad 4 by the pressing force F, and the surface of the pad 4 is elastically deformed as shown in FIG. To do.

  The center part of the lower surface of the pad conditioner 11 is not elastically deformed because the abrasive grain base 40 is directly joined to the flat region 21 of the disk-shaped base metal 20. Therefore, by pressing a plurality of abrasive grains 42 arranged at the center of the lower surface of the abrasive grain base 40 against the surface of the pad 4, the surface of the pad 4 is ground flat and the flatness of the surface of the pad 4 is restored. can do.

  By re-grinding in this manner, the flatness of the pad 4 is restored, and the wafer 6 can be polished again. For polishing the wafer 6, 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 alkali solution for etching or the like is supplied onto the pad 4 as a liquid slurry s. Therefore, the slurry s flows between the wafer 6 held by the wafer carrier 5 and the pad 4, and the wafer 6 rotates with the wafer carrier 5. At the same time, the pad 4 rotates about the central axis 2. Further, one surface of the wafer 6 is polished by the pad 4.

Moreover, as shown in FIG. 3, since the pad conditioner 11 is pressed against the pad 4 by the pressing force F, the surface of the pad 4 is elastically deformed. Thereby, the plurality of abrasive grains 42 arranged on the outer peripheral portion of the pad conditioner 11 receives concentrated pressure due to elastic deformation on the surface of the pad 4. In order to disperse this pressure, the pad conditioner 11 includes an outer elastic member 30 formed in an annular shape. When the concentrated pressure is applied to the plurality of abrasive grains 42 arranged on the outer peripheral portion, the outer elastic member 30 is elastically deformed so that the outer peripheral portion of the pad conditioner 11 is on the upper side as shown in FIG. It is deformed to warp. Due to the elastic deformation of the pad conditioner 11, no pressure is concentrated on the plurality of abrasive grains 42 arranged on the outer periphery of the pad conditioner 11, and the surface of the pad 4 that is elastically deformed comes into contact. be able to.
Accordingly, the pressure applied to the plurality of abrasive grains 42 disposed on the entire pad conditioner 11 is substantially uniform without concentrating the pressure on the plurality of abrasive grains 42 disposed on the outer peripheral portion of the lower surface of the abrasive grain base 40. Thus, local wear of the abrasive grains 42 arranged on the outer peripheral portion can be prevented, and the abrasive grains 42 can be prevented from being worn in a short period of time.

Since the pad conditioner 11 has the flat region 21 of the disk-shaped base metal 20 and the abrasive grain base 40 directly joined to each other, the center portion of the lower surface of the pad conditioner 11 has a high elastic modulus. Thus, the surface of the pad 4 can be cut flat, and the flatness on the surface of the pad 4 can be recovered or maintained.
Further, since the pad conditioner 11 includes the outer elastic member 30 formed in an annular shape, the outer peripheral portion of the lower surface of the pad conditioner 11 has a low elastic modulus, and the pad conditioner 11 is elastically deformed. It can be deformed to warp upward. Accordingly, the pad conditioner 11 can reduce the pressure applied to the abrasive grains 42 disposed on the outer peripheral portion, and can apply a substantially uniform pressure to the abrasive grains 42 disposed on the entire pad conditioner 11. Therefore, the pad conditioner 11 can prevent local wear on the abrasive grains 42 and can extend the product life.

FIG. 4 is a diagram showing another embodiment of the present invention.
In this figure, the same parts as those shown in FIG. 2 in the embodiment described above are denoted by the same reference numerals, and the description thereof is omitted.
This embodiment differs from the pad conditioner 11 in one embodiment shown in FIG. 2 in that the shape of the disk-shaped base metal 20 and the outer elastic member 30 is changed, and the outer elasticity is changed as shown in FIG. The inner elastic member 50 is added inside the member 30.
That is, as shown in FIG. 4, the disk-shaped base metal 20 is formed in a disk shape having a flat upper surface and a lower surface, and the outer elastic member 30 is fixed to the outer periphery of the lower surface with an adhesive tape or an adhesive. The inner elastic member 50 is fixed to the central portion of the lower surface with an adhesive tape or an adhesive. The outer elastic member 30 has the same diameter as that of the disk-shaped base metal 20 and is formed as an annular member having a rectangular cross section. The thickness of the outer elastic member 30 has a certain thickness dimension.
The inner elastic member 50 is formed in a disc shape so as to have the same outer diameter as the inner diameter of the outer elastic member 30 and the same thickness as the outer elastic member 30. Therefore, the inner elastic member 50 is positioned and fixed inside the outer elastic member 30.
Further, the elastic modulus of the inner elastic member 50 is set lower than the elastic modulus of the outer elastic member 30. Accordingly, in the configuration shown in FIG. 4, the pad conditioner 11 can have an outer peripheral portion having a low elastic modulus and a central portion having a high elastic modulus and existing inside the outer peripheral portion. become.
Therefore, in the embodiment shown in FIG. 4 as well, as in the embodiment shown in FIGS. 2 and 3, the pad conditioner 11 can follow the elastic deformation of the pad while cutting the surface of the pad 4 flat. . Therefore, the life of the pad conditioner 11 can be increased.

DESCRIPTION OF SYMBOLS 1 CMP polishing apparatus 2 Rotating shaft 3 Rotating table 4 Pad 5 Wafer carrier 6 Wafer 8 Conditioner mechanism 9 Rotating shaft 10 Arm 11 Pad conditioner 20 Disc-shaped base 21 Flat area 22 Inclined area 30 Outer elastic member 40 Abrasive base 41 Base part 42 A plurality of abrasive grains 43 Adhesive layer 50 Inner elastic member

Claims (6)

An abrasive substrate having an abrasive surface for polishing against the pad;
A disk-shaped base metal that supports the abrasive base;
An outer elastic member disposed in an outer peripheral portion between the disk-shaped base metal and the abrasive base, and formed in an annular shape;
A pad conditioner comprising: The pad conditioner according to claim 1,
A pad conditioner comprising a flat region formed by directly joining the disk-shaped base metal and the abrasive grain base. The pad conditioner according to claim 2,
The pad conditioner, wherein a thickness dimension of the outer elastic member increases from the inner side in the radial direction toward the outer side. The pad conditioner according to claim 1,
An inner elastic member disposed inside the outer elastic member;
The pad conditioner, wherein an elastic modulus of the outer elastic member is set lower than an elastic modulus of the inner elastic member. It is a pad conditioner as described in any one of Claims 1-4,
The pad conditioner, wherein a width dimension in a radial direction of the outer elastic member is in a range of 1/6 to 1/3 of a diameter of the disk-shaped base metal. It is a pad conditioner as described in any one of Claims 1-5,
The pad conditioner has a maximum deformation amount in a range of 40 μm to 200 μm.

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