JP2006026793A - Cutting tool - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cutting tool capable of reducing working failure generated at groove working of a polishing pad constituted by a viscoelastic resin. <P>SOLUTION: In a structure of the cutting tool, a plurality of single blades 10 are projected on one side surface of a tool body with a constant gap. The shape of the single blade has blade width W of 0.1 mm-2.0 mm, a lateral clearance angle α of 4°-10°, a rake angle β of 0°-5° and a front clearance angle δ of 0°-30°. A blade angle θ is determined by the selected rake angle β and the clearance angle δ. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a cutting tool for grooving a semiconductor polishing pad.

  In the field of semiconductor manufacturing, with the high integration by miniaturization and multilayering of semiconductor elements, the planarization technology of semiconductor layers and metal layers has become an important elemental technology. When forming an integrated circuit on a wafer, if the layers are stacked without flattening the unevenness due to the electrode wiring or the like, the step becomes large and the flatness becomes extremely poor. Further, when the step becomes large, it becomes difficult to focus on both the concave portion and the convex portion in photolithography, and miniaturization cannot be realized. Therefore, it is necessary to perform a planarization process for removing irregularities on the wafer surface at an appropriate stage during the lamination. For the flattening process, an etching back method for removing uneven portions by etching, a film forming method for forming a flat film by plasma CVD (Chemical Vapor Deposition), a fluidizing method for flattening by heat treatment, a concave portion by selective CVD, etc. There is a selective growth method for embedding.

  The above method has problems that it is appropriate depending on the type of film such as an insulating film and a metal film, and that the region that can be flattened is extremely narrow. As a planarization technique that can overcome such problems, there is planarization by CMP.

  In the flattening process by CMP, while the polishing composition in which fine silica particles (abrasive grains) are suspended is supplied to the surface of the polishing pad, the pressed polishing pad and the silicon wafer as the object to be polished are relatively moved. By polishing the surface, the wafer surface over a wide range can be flattened with high accuracy.

  Polishing pads have been improved for the purpose of improving polishing characteristics in CMP. As one of the improvements of the polishing pad, there is a process of providing a plurality of grooves in the surface portion on the side in contact with the object to be polished. The groove provided in the surface portion has a function of holding the polishing composition and a function of removing coarse particles that cause scratches such as polishing dust, for example, concentric circles, spirals, and lattices. Provided.

  Conventional examples of cutting tools for performing grooving are disclosed in Patent Document 1 and Patent Document 2. In the turning tool described in Patent Document 1, the shape of a single blade for turning a single groove has a front relief angle of 65 to 45 degrees corresponding to a blade angle of 15 to 35 degrees, and a lateral relief angle of 1 to 3 degrees. And a multi-blade unit in which the single blades are aligned and projected. The turning tool described in Patent Document 2 is similar to the turning tool described in Patent Document 1, the blade angle is in the range of 30 to 35 degrees, the rake angle is in the range of 20 to 10 degrees, and the front clearance angle is 55 degrees. It is a multi-blade tool in which a single bit formed in a range of up to 45 degrees and a side clearance angle in a range of 0 degrees to 2 degrees, or two or more such single bits are arranged.

JP 2001-18164 A JP 2002-11630 A

  Many polishing pads are made of viscoelastic resin, and it is difficult to perform desired groove processing. For example, when grooving is performed using the turning tools described in Patent Document 1 and Patent Document 2, a large number of burrs are generated, and machining defects that occur irregularly due to a lump of cutting waste become a problem. In addition, there is a problem that the tool is damaged due to vibration during processing.

  The objective of this invention is providing the cutting tool which can reduce the processing defect which generate | occur | produces in the case of the groove process of the polishing pad comprised with the viscoelastic resin.

The present invention is a cutting tool for grooving a semiconductor polishing pad made of a viscoelastic resin, having a lateral relief angle of 4 ° to 10 °, a rake angle of 0 ° to 5 °, A cutting tool having a single blade with a clearance angle of 0 ° to 30 °.
The material is high-speed steel or cemented carbide.
The rake face is mirror-finished.

  According to the present invention, there is provided a cutting tool for grooving a semiconductor polishing pad made of a viscoelastic resin. The lateral clearance angle is set to 4 ° to 10 °, the rake angle is set to 0 ° to 5 °, and the front clearance angle is set to 0 ° to 30 °.

  Thereby, the process defect which generate | occur | produces at the time of the groove process of a polishing pad can be reduced by optimizing the shape of a blade.

Further, according to the present invention, the material is high speed steel or cemented carbide.
Thereby, tool life, processing accuracy, etc. can be improved by selecting the optimal blade material.

According to the present invention, the rake face is mirror-finished.
As a result, the frictional resistance on the rake face is reduced, and the cutting waste is more easily discharged.

  In the groove processing of the polishing pad, a plurality of grooves are provided on the surface portion of the polishing pad on the side in contact with the object to be polished by relatively moving the cutting tool having a blade having a predetermined shape and the polishing pad.

  FIG. 1 is a diagram showing a configuration of a cutting tool 1 according to an embodiment of the present invention. FIG. 1A is a front view, FIG. 1B is a side view, and FIG. 1C is a bottom view. FIG. 2 is an enlarged view of the cutting edge portion of the single blade 10. 2A is a front view, and FIG. 2B is a side view.

  The structure of the cutting tool 1 is such that a plurality of single blades 10 project from one side of the tool body 20 at intervals P. The shape of the single blade 10 is represented by a blade width W, a side clearance angle α, a rake angle β, a front clearance angle δ, and a blade angle θ as shown in the figure.

  In this embodiment, the blade width W is 0.1 mm to 2.0 mm, the lateral clearance angle α is 4 ° to 10 °, the rake angle β is 0 ° to 5 °, and the front clearance angle δ is 0 ° to 30 °. The blade angle θ is determined by the selected rake angle β and clearance angle δ. For example, when the rake angle β is 0 ° and the front clearance angle δ is 15 °, the blade angle θ is set to 75 °.

  The blade width W is selected according to the groove width of the groove to be processed. By adjusting the side clearance angle α, it is possible to adjust the easiness of flow of the cutting waste (dischargeability), which greatly affects the wear and breakage of the cutting tool. By increasing the lateral clearance angle α to 4 ° to 10 °, it is possible to facilitate the flow of cutting waste.

  The rake angle β affects the cutting resistance. By making the rake angle β relatively small from 0 ° to 5 °, the cutting resistance can be reduced and the occurrence of burrs can be prevented. Moreover, since the distortion which cutting waste receives becomes small, cutting waste is discharged | emitted continuously. The clearance angle δ affects the wear and breakage of the cutting tool. By reducing the front clearance angle δ from 0 ° to 30 °, wear can be reduced and the tool can be prevented from being damaged. In particular, the front clearance angle δ is preferably set to 15 °. The interval P between the single blades may be set according to the size of the groove to be processed, but the interval P is also set larger as the groove width increases, that is, the blade width increases. For example, when the blade width is 0.1 mm to 0.25 mm, the interval P is set to 1.0 mm to 1.5 mm, and when the blade width is 0.25 mm to 1.0 mm, the interval P is 1.5 mm to 1.5 mm. When the blade width is set to 3.0 mm and the blade width is 1.0 mm to 2.0 mm, the interval P is set to 3.0 mm to 5.0 mm.

  Furthermore, it is preferable to perform mirror finishing on the rake face 10a. As a result, the frictional resistance on the rake face is reduced, and the cutting waste is more easily discharged. The mirror finish is performed, for example, by polishing the rake face 10a.

  Since the groove processing on the polishing pad is high-speed and high-temperature processing, the material of the cutting tool 1 is required to have wear resistance and toughness. For example, high-speed steel or cemented carbide is preferable as the material. High-speed steel is a material obtained by adding a relatively large amount of alloy elements such as chromium, molybdenum, tungsten, vanadium, and cobalt to high-carbon steel. A cemented carbide is a material mainly composed of a carbide of a refractory metal.

  Further, a ceramic coating may be applied to the surface of the blade. The cutting tool for optimum grooving can be realized by satisfying the wear resistance by the ceramic coating and satisfying the toughness by the material. Since the tool life is improved when the toughness is increased, a cemented carbide having a high toughness is preferable to the high speed steel when it is desired to improve the tool life.

  If attention is paid to the reduction of burrs, the surface of the polishing pad and the cross-section processing accuracy, a material with high toughness is not always optimal. In particular, it is preferable to select a material suitable for the cutting speed during processing.

  FIG. 3 is a schematic diagram illustrating the configuration of the groove processing apparatus 100. The grooving apparatus 100 mainly includes a support table 101 that fixes and supports a polishing pad that is an object to be cut, a table drive unit 102 that drives the support table 101 to rotate and linearly drive, and a tool body 20 of the cutting tool 1. It is configured to include a blade part 103 that is held above the support table 101 and causes the single blade 10 to contact the polishing pad. The support table 101 fixes and supports the polishing pad on the table by fixing means such as an electrostatic chuck or a vacuum chuck. The table driving unit 102 rotates the support table 101 around the vertical axis and linearly moves the supported polishing pad in the radial direction. The blade part 103 moves the held cutting tool 1 in the vertical direction and the radial direction of the supported polishing pad. Rotation direction, rotation speed, linear movement direction, linear movement distance, linear movement speed, and vertical movement direction, vertical movement distance, radial movement direction, radial movement distance, contact pressure of the blade 103 Are controlled by a control unit (not shown).

  In the case of concentric grooving, the cutting tool 1 as shown in FIG. 1 is held on the blade portion 103 such that the single blade 10 is arranged in the radial direction of the polishing pad. The support table 101 that supports the polishing pad is driven to rotate by the table driving unit 102, and the cutting tool 1 is moved in the vertical direction to contact the polishing surface of the polishing pad. When the position of the cutting tool 1 is fixed in a state in which the cutting tool 1 is in contact, and one or more rotations are made, grooves corresponding to the number of single blades are formed in the polishing pad. The cutting tool 1 is moved in the radial direction of the polishing pad and contacted again to form a groove. By repeating this, concentric grooves can be formed over the entire surface of the polishing pad.

  In the case of spiral grooving, a cutting tool having a single blade is used, the support table 101 that supports the polishing pad is rotated by the table driving unit 102, and the cutting tool is moved in the vertical direction. Contact with the polishing surface of the polishing pad. Almost simultaneously with the contact, the cutting tool is moved in the radial direction. By simultaneously rotating the support table 101 and moving the cutting tool in the radial direction, a spiral groove can be formed.

  In the case of lattice-shaped grooving, the cutting tool 1 as shown in FIG. 1 is held on the blade portion 103 such that the single blade 10 is arranged in the radial direction of the polishing pad. The cutting tool 1 is moved in the vertical direction to come into contact with the polishing surface of the polishing pad, and the support table 101 that supports the polishing pad is driven linearly by the table driving unit 102. This is repeated to form a plurality of grooves parallel to each other. Next, by rotating the support table 101 by 90 ° to form a plurality of grooves that are parallel to each other, it is possible to perform lattice-like groove processing.

  As described above, in any grooving process, the grooving process is performed by moving the cutting tool and the polishing pad in contact with each other. The relative moving speed at this time is the cutting speed. When the cutting speed is relatively slow, for example, in the range of 0.1 m / min to 500 m / min, it is preferable to use high speed steel, and when the cutting speed is relatively fast, for example, 300 m / min to 1,000 m / min. In the range, it is preferable to use cemented carbide. In the case of concentric grooving, the peripheral speed when the support table 101 is driven to rotate corresponds to the cutting speed. In the range of 300 m / min to 500 m / min, the optimum material of the cutting tool 1 may be determined according to the dimensions of the groove to be cut, the material of the polishing pad, etc. in addition to the cutting speed.

  As described above, by optimizing the shape of the blade, it is possible to reduce processing defects that occur during groove processing of the polishing pad. Furthermore, tool life and machining accuracy can be improved by selecting an optimum blade material.

It is a figure which shows the structure of the cutting tool 1 which is one Embodiment of this invention. It is the figure which expanded the blade edge | tip part of the single blade. 1 is a schematic view showing a configuration of a groove processing apparatus 100. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cutting tool 10 Single blade 10a Rake face 20 Tool main body 100 Groove processing apparatus 101 Support table 102 Table drive part 103 Blade part

Claims (3)

A cutting tool for grooving a semiconductor polishing pad made of a viscoelastic resin,
A cutting tool having a single blade having a side clearance angle of 4 ° to 10 °, a rake angle of 0 ° to 5 °, and a front clearance angle of 0 ° to 30 °.   The cutting tool according to claim 1, wherein the material is high-speed steel or cemented carbide.   The cutting tool according to claim 1 or 2, wherein the rake face is mirror-finished.

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