JP2010149221A - Tool and method for dressing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To stably perform dressing for a relatively long time. <P>SOLUTION: The dressing tool is in slide-contact with a polishing pad face removing clogging of the polishing pad face, and includes a plate having a plurality of through-holes extending from a first main face to a second main face and abrasive grains disposed in the through-holes. The through-hole has a diameter reduced part smaller than an opening diameter on the second main face side, and the abrasive grains abut on an inner face of the through-hole in the diameter reduced part, and is jointed to the plate through a bonding material disposed on the inner face of the through-hole with a part of it protruded from the first main face. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  TECHNICAL FIELD The present invention relates to a dressing tool and dressing method for conspicuous polishing cloth surface, and particularly to dressing of a polishing cloth used in a chemical mechanical polishing (hereinafter abbreviated as “CMP”) method of a semiconductor device. is there.

  In recent years, with the increase in the density of semiconductor devices, the focus margin of an exposure apparatus for transferring a pattern has been narrowed, and the conventional planarization methods such as the reflow method, SOG (Spin On Glass), and the like, and the etch back method have wide areas. Crossing flattening has become difficult. For this reason, a CMP method for polishing a semiconductor substrate by a mechanical action and a chemical action has come to be used.

  In the CMP method, generally, a semiconductor wafer or the like as an object to be polished is mounted on a carrier, the carrier is lowered onto a polishing cloth, and a load is applied to the semiconductor wafer while supplying an abrasive. Rotate the same and perform polishing. As the polishing cloth, hard foam polyurethane or the like is generally used. When the semiconductor wafer is polished by the CMP method, a phenomenon occurs in which the polishing material silica is clogged in the opening on the surface of the polishing cloth and the polishing rate decreases. For this reason, when using the CMP method, dressing for removing clogging on the surface of the polishing pad is performed simultaneously with polishing of the semiconductor wafer or at regular intervals (for example, refer to Non-Patent Document 1).

FIG. 4 is a sectional view showing a conventional dressing tool. The diamond abrasive grains 13 are embedded in the binder 14 and fixed so as not to drop off. In the dressing tool of FIG. 4, diamond abrasive grains 13 are fixed over the entire surface of the material to be fixed, and there are diamond abrasive grains 13 in a state of floating from the substrate 17. In patent document 1, it is a member to be polished by substituting the binder for fixing the diamond abrasive grains 13 with an inorganic bond such as borosilicate glass instead of the nickel plating 14 that has been generally used conventionally. The point which prevents the contamination of a wafer is described.
Solid State Technology, Oct. 1994, p.66, left column 2nd line to right column 9th line JP 2001-239461 A

  However, even in the dressing tool described in Patent Document 1, there is a relatively high risk that the inorganic binder such as borosilicate glass is eroded and the diamond abrasive grains 13 fall off, and the product life that can be used as a dressing tool is relatively short. It was. In addition, the bonding material that has been worn out and dropped off from the surface of the dressing tool may damage the wafer.

  This invention is made | formed in view of the said problem, Comprising: The objective is to provide the dressing tool with which damage | damage and drop | offset, such as an abrasive grain, a binder, and a plate, were suppressed.

  Accordingly, in view of the above problems, the present inventor is a dressing tool that is slidably contacted with the surface of the polishing pad and removes clogging of the surface of the polishing pad, and has a plurality of through holes extending from the first main surface to the second main surface. And a through-hole having a reduced diameter portion smaller in diameter than the opening diameter on the second main surface side, and the abrasive grains The diameter-reduced portion is in contact with the inner surface of the through-hole, and a part of the reduced-diameter portion projects from the first main surface, and is joined to the plate via a bonding material disposed on the inner surface of the through-hole. A dressing tool is provided.

  Also provided is a dressing method characterized in that a dressing tool is brought into sliding contact with the surface of the polishing pad to dress the polishing pad.

  According to the structure of this invention, a board | substrate and an abrasive grain are couple | bonded comparatively firmly and drop-off | omission of an abrasive grain is suppressed. Further, the concentration of stress on the opening of the substrate is suppressed, and the substrate itself is also prevented from being damaged or dropped off. The dressing tool of the present invention can stably perform the dressing process for a relatively long period of time.

  1-3 is a schematic sectional drawing which shows one Example of the dressing tool concerning this invention.

  A dressing tool 1 shown in FIG. 1 includes a plate 2 having a plurality of through-holes 5 extending from a first main surface 2a to a second main surface 2b, and is disposed in the through-hole 5, and a part thereof is a first main surface. The diamond abrasive grain 3 protruded from 2a and the base body 7 joined to the plate 2 are provided. The diamond abrasive grains 3 are joined to the plate 2 via a binding material 4 disposed on the inner surface of the through hole 5. Further, the second main surface 2b of the plate 2 is joined to the surface of the base 7 via a bonding material 6 made of, for example, an acrylic adhesive.

  The substrate 7 may be formed in a flat plate made of ceramic, and when ceramic is used, it is particularly preferable that the material is alumina or zirconia. In particular, when the substrate 7 is made of alumina or zirconia, the elution of the metal component can be relatively reduced. Further, when the material of the substrate 7 is alumina, the dressing tool 1 has a relatively high rigidity, and at the same time, the manufacturing cost can be reduced. On the other hand, when the plate 2 is zirconia, the plate 2 and the base 7 are made of the same material, and the difference in thermal expansion coefficient can be made relatively small.

  In addition, as a mechanical characteristic of the base | substrate 7, it is preferable that Young's modulus is 190 GPa or more and Vickers hardness is 9 GPa or more. If the Young's modulus is lower than 190 GPa, the deformation due to mechanical load during processing or use becomes large, which is not preferable, and if the Vickers hardness is lower than 9 GPa, the diamond abrasive grains 3 are applied to the substrate 7. This is not preferable because biting occurs and the diamond abrasive grain height may change.

Here, the following materials can be used as alumina.
(1) Alumina (Al ₂ O ₃ ) 99 to 99.9% by weight of silica (SiO ₂ ), magnesia (MgO), calcia (CaO) as a total of 0.1 to 1% by weight as a sintering aid After being added and formed into a desired shape, it is fired at a temperature of 1500 to 1800 ° C. in an air atmosphere or a vacuum atmosphere. (2) Yttria with respect to 93 to 99% by weight of alumina (Al ₂ O ₃ ) 1-7 wt% of zirconia (ZrO ₂ ) stabilized or partially stabilized with a stabilizer such as (Y ₂ O ₃ ), magnesia (MgO), calcia (CaO) or ceria (CeO ₂ ) , After being molded into a desired shape, and then fired at 1500 to 1700 ° C. in an air atmosphere, a hydrogen atmosphere or a nitrogen atmosphere (3) Alumina (Al ₂ O ₃ ) 60 to 80% by weight In addition, after adding titanium carbide (TiC) in an amount of 40 to 20% by weight to form a desired shape, it is possible to use one that is fired at a temperature of 1300 to 2000 ° C. in an air atmosphere or a reduced pressure atmosphere. .

As the zirconia, 3～9Mol% of yttria _(Y 2 _{O 3)} in partially stabilized zirconia (ZrO ₂₎ and, 16～26Mol% magnesia (MgO) in partially stabilized zirconia _(ZrO 2), or after forming 8～12Mol% of calcia (CaO) in partially stabilized zirconia (ZrO ₂₎ and 8～16Mol% of ceria zirconia partially stabilized with (CeO ₂₎ a (ZrO ₂₎ into a desired shape, What was baked at the temperature of 1400-1700 degreeC in air | atmosphere atmosphere or a vacuum atmosphere can be used.

The plate 2 is preferably made of ceramics, and particularly preferably made of zirconia (ZrO ₂ ) as a material. Moreover, as a mechanical characteristic of the plate 2, a thing with a high toughness value is preferable, and if K1c is 5 or more, it is preferable. Furthermore, it is more preferable if the Young's modulus is 190 GPa or more and the Vickers hardness is 9 GPa or more. The plate 2 is a disk-shaped member in which the first main surface 2a and the second main surface 2b are substantially circular. In the plate 2 of the present embodiment, the diameter of each main surface is about 25 mm, and the thickness is about 0.2 to 0.3 mm.

  By using zirconia as a main component of the material of the plate 2, it is possible to obtain an effect of preventing the bonding material 4 from being eroded, and it is possible to improve wear resistance and prevent damage from the edge portion. Zirconia is easy to process thin because of its high strength and toughness. For this reason, even if the diamond abrasive grains 3 are relatively small, the plate 2 having a relatively small thickness suitable for the diamond abrasive grains 3 can be produced at a low cost with a relatively high shape accuracy. Further, by combining the base 7 with the one formed of zirconia, the thermal expansion coefficient of the base 7 and the plate 2 can be made substantially the same, and the change in accuracy of the dressing tool due to heat can be relatively reduced.

  In the dressing tool 1, a through hole 5 is formed at a predetermined position in the plate 2, and diamond abrasive grains 3 are inserted into the through hole 5. The through hole 5 of the plate 2 has a reduced diameter portion 5a having a diameter smaller than the opening diameter on the second main surface 2b side of the plate 2, and the diamond abrasive grains 3 are formed in the through hole 5 in the reduced diameter portion 5a. Is in contact with the inner surface. Note that the diameter of the through hole refers to the diameter of a circle inscribed in a cross-sectional shape substantially parallel to the main surface of the plate. The reduced diameter portion refers to a portion where the inscribed circle of the cross-sectional shape has a length of, for example, 90% or less with respect to the diameter of the inscribed circle of the opening of the second main surface.

  The position of the reduced diameter portion 5 a, particularly the length from the reduced diameter portion 5 a to the first main surface 2 a of the plate 2 is set according to the length of the diamond abrasive grains 3. In the dressing tool 1, the diamond abrasive grain 3 protrudes 20 to 40% from the through hole 5 on the surface side of the plate 2 in a state where the diamond abrasive grain 3 is in contact with the inner surface of the through hole 5 in the reduced diameter portion 5 a. The thickness is set. For example, when diamond abrasive grains having a particle size of 80/100 specified in JIS B4130 (1982) are used as the abrasive grains 3, the length from the first major surface 2a to the reduced diameter portion 5a is set to 0.01 to 0, for example. .04mm is enough. In this case, the opening diameter in the second main surface 2b may be set to 0.7 mm, for example, and the diameter in the reduced diameter portion may be set to 0.2 mm, for example. In addition, although the magnitude | size of the opening diameter of the 1st main surface 2a is not specifically limited, It is preferable that it is substantially equivalent to the diameter in a reduced diameter part.

  In the dressing tool 1, the through hole 5 includes a reduced diameter portion 5 a, and the diamond abrasive grains 3 are mechanically held relatively firmly in the reduced diameter portion, and the first main surface 2 a of the diamond abrasive grains 3. The protrusion length from the head is defined with relatively high accuracy. Thereby, dropping of the diamond abrasive grains 3 is suppressed, and the distribution of dressing performance is also reduced.

  Further, as shown in FIG. 1, the inner surface portion of the reduced diameter portion 5a of the through-hole 5 is a fulcrum that mechanically holds and supports the diamond abrasive grains 3, and receives a relatively large stress during the dressing process. . In the dressing tool 1, the cross-sectional angle at the reduced diameter portion 5 a of the inner surface of the through hole 5 is an obtuse angle, and the stress applied to the reduced diameter portion 5 a is widely dispersed on the inner surface of the plate 2. For this reason, in the dressing tool 1, the occurrence of breakage or dropout of the plate 2 is relatively reduced. Further, the binding material 4 disposed on the inner surface of the through hole 5 has an action of suppressing the movement of the diamond abrasive grains 3 with the reduced diameter portion 5a as a fulcrum, thereby causing the plate 2 to be broken or dropped off. It is more effectively suppressed.

  In the dressing tool 1, the inner surface of the through hole 5 is substantially perpendicular to the first main surface 5 a in the region from the reduced diameter portion 5 a to the first main surface 2 a, and the through hole 5 a and the diamond abrasive grains 3 Is relatively small on this inner surface. For this reason, on the side of the first main surface 2a from which the diamond abrasive grains protrude, the binding material 4 is relatively exposed, and the binding material 4 is detached during the dressing process, and contamination of the dressing object such as a polishing cloth is also caused. It is suppressed. Further, the binding material 4 is also disposed in the region extending from the reduced diameter portion 5a to the first main surface 2a, and the movement of the diamond abrasive grains 3 is well suppressed, and the plate 2 may be broken or dropped off. Are more effectively suppressed.

  In addition, the through-hole 5 should just be provided with the reduced diameter part 5a, and the cross-sectional shape is not specifically limited. For example, as shown in FIG. 2, the diameter of the reduced diameter portion 5a may be smaller than the opening diameter of the first main surface 2a. However, as described above, in order to more effectively suppress the breakage or dropout of the plate 2, the inner surface of the through hole 5 is the first main surface 5a in the region from the diameter portion 5a to the first main surface 2a. And approximately vertical. When the inner surface of the through hole 5 is substantially perpendicular to the first main surface 5a in the region from the reduced diameter portion 5a to the first main surface 2a, the plate 2 provided with the through hole 5 is formed by press molding. It is possible to manufacture the device relatively easily at a low cost, which is also preferable in this respect.

  The arrangement of the through holes 5 is arbitrary. For example, the through holes 5 may be arranged in the same positional relationship like a grid, or may be in a radially arranged shape.

  In any embodiment, the size d1 of the reduced diameter portion 5a of the through hole 5 is determined by the grain size and length of the diamond abrasive grain 3, and the diamond abrasive grain 3 can be held without penetrating. The set diamond abrasive grains 3 may be set to a size that can ensure the protruding height.

  The diamond abrasive grain 3 may be either synthetic diamond or natural diamond, and is preferably a so-called blocky type having a crystal grown, for example, having an approximately octahedral shape or an approximately dodecahedron shape. The blocky type diamond granite has a long shape, and the length and particle size of the grain are controlled relatively well. By disposing the blocky type diamond abrasive grains 3 in the plurality of through holes 5, the protruding length of the diamond abrasive grains 3 from the respective through holes 5 can be controlled relatively well.

  The diamond abrasive grains 3 are joined to the plate via a binding material 4 disposed on the inner surface of the through hole 5. Further, the plate 2 has the second main surface 2b joined to the surface of the base 7 via a binder 6 made of, for example, an acrylic adhesive.

The binder 4 is preferably a material having sufficient bonding strength and toughness, and is preferably an inorganic binder mainly composed of SiO ₂ such as boron silicate glass or quartz glass. The binding material 4 may be a resin material. The resin material is preferably a polyimide resin, a urethane resin, a fluorine resin, or an epoxy resin. Among them, the epoxy resin is particularly preferable in terms of bonding strength, chemical resistance, hardness, and change with time. By using an inorganic material or a resin material as the binding material 4, metal contamination in the dressing process can be suppressed.

  Next, the manufacturing method of the dressing tool 1 of this embodiment is demonstrated.

  First, diamond abrasive grains 3 are prepared. As the diamond abrasive grain 3, for example, a large number of diamond abrasive grains having a particle size of 80/100 specified in JIS B4130 (1982) are prepared and selected based on size and shape. For example, a sieve having a hole diameter slightly larger than the diameter d1 of the reduced diameter portion 5a of the through hole 5 is used, and the grindstone that has passed through the holes in the sieve is removed from a large number of diamond abrasive grains and remains on the sieve. Abrasive grains are used as diamond abrasive grains 3.

  The plate 2 is formed of ceramics, preferably zirconia raw material powder, using a CIP, mechanical press or doctor blade to obtain a formed shape. Next, the obtained shaped body is processed into a desired size by cutting, and then fired in an air atmosphere to obtain a sintered body. Further, after firing, grinding is performed with a diamond grindstone on a surface grinder to obtain a predetermined size.

  For example, the zirconia raw material powder is molded into a predetermined shape and then fired in the air atmosphere to obtain a molded body having the shape shown in FIG. Thereafter, the molded body is polished from the side of the surface 15 shown in FIG. 3A to obtain a plate 2 in which a plurality of through holes 5 from the first main surface 2a to the second main surface 2b are formed (FIG. 3). 3 (b) The through-holes 5 formed in the plate 2 may be formed by a cutting process after obtaining a generated shape, or may be formed by a grinding process after obtaining a sintered body.

Next, as shown in FIG. 3 (c), the diamond abrasive grains 3 are inserted into the through holes 5 from the second main surface 2 b side with the produced plate 2 set on the decompression jig 18. The through hole 5 has a reduced diameter portion 5 a, and the diamond abrasive grains 3 are held by the plate 2 in contact with the inner surface of the through hole 5 at the reduced diameter portion 5 a. In this state, a glass paste having a composition of SiO ₂ —Al ₂ O ₃ —RO (RO is an oxide of an alkaline earth element) is applied from the second main surface 2b side, and is sufficiently dried in an air atmosphere. After that, baking is performed at 900 ° C. in a vacuum atmosphere and bonding is performed.

  Thereafter, the plate 2 to which the diamond abrasive grains 3 are bonded and the base 3 made of alumina, for example, are bonded to each other through, for example, an acrylic adhesive, whereby the dressing tool 1 is obtained.

  It goes without saying that the present invention is not limited to the above-described embodiments, and can be applied to improvements and modifications without departing from the scope of the present invention.

It is a schematic sectional drawing which shows one Embodiment of the dressing tool which concerns on this invention. It is a schematic sectional drawing which shows other embodiment of the dressing tool which concerns on this invention. It is a schematic sectional drawing which shows an example of the manufacturing method of the dressing tool which concerns on this invention. It is a schematic sectional drawing which shows an example of the conventional dressing tool.

Explanation of symbols

1, 10 Dressing tool 2 Plate 3, 13 Diamond abrasive grain 4 Binder 7, 17 Base 14 Nickel plating d1 Opening

Claims (8)

A dressing tool that is in sliding contact with the surface of the polishing pad and removes clogging of the surface of the polishing pad,
A plate having a plurality of through holes extending from the first main surface to the second main surface;
An abrasive disposed in the through hole,
The through hole has a reduced diameter portion having a smaller diameter than the opening diameter on the second main surface side,
The abrasive grains are in contact with the inner surface of the through-hole at the reduced diameter portion, and a part of the abrasive grain protrudes from the first main surface. A dressing tool characterized by being joined.   2. The binding material is arranged on both the second main surface side with respect to the reduced diameter portion and the first main surface side with respect to the reduced diameter portion. The dressing tool described.   The dressing tool according to claim 1 or 2, wherein an inner surface of the through hole is substantially perpendicular to the first main surface in a region from the reduced diameter portion to the first main surface.   The dressing tool according to claim 1, wherein the abrasive grains are made of diamond.   The dressing tool according to claim 1, wherein the binder is made of glass.   The dressing tool according to claim 5, wherein the resin material is formed of an epoxy resin.   The dressing tool according to claim 1, wherein the plate is mainly composed of zirconia. A dressing method comprising: bringing the dressing tool according to claim 1 into sliding contact with a surface of a polishing pad, and dressing the polishing pad.

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