JP5033630B2 - Tool having sintered body polishing portion and method for manufacturing the same - Google Patents

Description

  The present invention relates to a tool having a sintered body polishing portion and a manufacturing method thereof. In particular, the present invention is for a chemical-mechanical polishing (abbreviated as CMP) pad mainly composed of hard urethane, a polishing tool capable of processing various semiconductor materials with high flatness and high efficiency, and a polishing tool thereof. The present invention relates to an effective manufacturing method.

  In recent years, CMP has been used to planarize metal film wafers such as interlayer insulating films and silicon as the number of wiring layers in VLSI devices has increased. In order to maintain a high level of a polishing pad (generally made of rigid foamed polyurethane) used in CMP and a wafer polishing rate, it is necessary to condition the surface of the polishing pad constantly or intermittently.

Conventionally, during conditioning of this polishing pad, a tool in which diamond abrasive grains are fixed to a substrate by electrodeposition has been used. As an example of such an electrodeposition type conditioning tool, in the center of the circular surface of the disk-shaped base, a hollow region where no abrasive grains are arranged is a first on the outside, and a second on the outside. Each of the abrasive layer regions is provided, and the first abrasive layer region is provided with a plurality of rows of small abrasive layer portions at intervals, and each of the small abrasive layer portions is formed of a raised portion having a substantially partial spherical shape. The superabrasive grains are fixed to the surface with a metal plating phase, and the second abrasive layer region is formed by fixing the superabrasive grains to the ring-shaped circumferential ridge with the metal plating phase. A rotary polishing tool is known (Patent Document 1).
Such electrodeposition type tools are not always satisfactory in holding power because the abrasive grains are only physically fixed to the substrate by the electrodeposited nickel. The abrasive grains dropped out and there was room for improvement in tool life.

Also known is a polishing tool having an abrasive layer in which abrasive grains made of diamond or the like are fixed on a circular rotation plane with a resin bond material, and slits are provided radially and concentrically on the surface of the abrasive layer (patent) Reference 2).
However, since the retention strength of the abrasive grains by the resin bond material is not always at a satisfactory level, a sufficient tool life cannot be obtained depending on the application, and the electrodeposition tool is not at a satisfactory level.

Also, a dresser is known in which a polycrystalline diamond thin film is formed on the working surface of a base metal having a convex portion by a vapor phase synthesis method (Patent Document 3).
However, it is difficult to form a diamond thin film faithfully to the small unevenness of the base metal by the vapor phase synthesis method, and sufficient accuracy cannot be obtained, and the bonding force between the thin film and the base metal is not sufficient. I can't say that.

  The conventional polishing tool (pad conditioner) as described above has a structure in which a plurality of abrasive grains having different particle diameters are fixed to a substrate (base metal), so that a uniform abrasive grain (vertex) level can be obtained. The conditioning process uses only the most protruding particles on the substrate (base metal) surface, resulting in excessive consumption of these particles that are subjected to excessive loads, before eventually reaching the original tool life. Often unavailable.

If a wafer such as silicon can be processed with a tool in which superabrasive grains such as diamond are fixed on the surface of a rigid metal base metal, regardless of the urethane foam polishing pad and loose abrasive grains, the time required for conditioning This is desirable because it saves money and costs, but for this to happen, the superabrasive layer of diamond, etc., which is placed on the base metal and forms the cutting edge, must have a highly accurate plane and be able to hold. However, such a tool has not been fully realized.
JP 2002-337050 A JP 2004-291184 A Japanese Patent Laid-Open No. 10-071559

  An object of the present invention is to provide a polishing tool capable of high-efficiency processing and an effective manufacturing method thereof in which the problem of the strength of fixing abrasive grains to a substrate, the problem of uneven polishing surface, and the like are solved. In particular, an object of the present invention is to provide a polishing tool capable of processing a surface of a semiconductor wafer or the like with high accuracy and high efficiency as a CMP pad conditioner.

In the polishing tool having a polishing portion made of a superabrasive sintered body, in the course of earnest research to solve the above problems, the inventor forms a plurality of specific polishing units in the polishing portion. As a result of finding out that such a problem can be solved and further researching it, the present invention has been completed.
That is, the present invention is a polishing tool having a polishing portion made of a superabrasive sintered body, wherein the polishing portion includes a plurality of polishing units having a top portion, and the top portions are substantially coplanar with each other, It relates to a polishing tool.
Further, in the present invention, the polishing portion is made of a superabrasive sintered body integrated with a cemented carbide backing material, and the polishing unit is formed by providing a linear groove group in the polishing portion. The present invention relates to the polishing tool.
Moreover, this invention relates to the said grinding | polishing tool by which blade attachment is performed to the top part.
Furthermore, the present invention relates to the polishing tool, wherein the polishing unit is a quadrangular pyramid or a truncated pyramid.

The present invention also relates to the above polishing tool, wherein the polishing unit has a quadrangular pyramid shape, and at least one side of the top is bladed.
Furthermore, the present invention relates to the polishing tool, wherein the polishing unit is a triangular pyramid shape or a triangular frustum shape.
The present invention also relates to the above polishing tool, wherein the polishing unit has a triangular frustum shape, and at least one side of the top is bladed.
Furthermore, this invention relates to the said grinding | polishing tool whose grinding | polishing unit is a shape which exhibits a linear ridgeline in the top part.
The present invention also relates to the above polishing tool, wherein the polishing unit is a quadrangular pyramid shape or a triangular pyramid shape, and the pitch of the polishing unit is 1500 μm or less and 200 μm or more.
Furthermore, the present invention relates to the above polishing tool, wherein the polishing unit is a quadrangular pyramid or a triangular pyramid, and the height of the polishing unit is 200 μm or less and 30 μm or more.
Moreover, this invention relates to the said polishing tool whose superabrasive grain is a diamond.
Furthermore, the present invention relates to the above polishing tool, wherein the nominal grain size of diamond is 40-60 μm or less.
The present invention also relates to the above polishing tool, wherein the superabrasive sintered body has a thickness of 0.1 mm or more.
Furthermore, this invention relates to the said grinding | polishing tool which is disk shape or annular | circular shape.

The present invention also relates to the above polishing tool, wherein the polishing part is disc-shaped or annular.
Furthermore, the present invention relates to the above polishing tool, wherein the outer diameter of the polishing part is 90 mm or more.
The present invention also relates to the above polishing tool, wherein the height of the top portion with respect to the bottom of the groove of the polishing portion is 1 mm or less.
Furthermore, the present invention relates to the above polishing tool, wherein the polishing part is composed of two or four divided polishing parts, and each of the divided polishing parts has a fan shape having the same central angle.
Further, according to the present invention, the divided polishing portion has two groove groups, the first groove group is provided in parallel to the radial edge of the divided polishing portion, and the second groove group is orthogonal to the first groove group. It is related with the said polishing tool currently formed.
Furthermore, the present invention relates to the above polishing tool, wherein the polishing part is composed of three or six divided polishing parts, and each of the divided polishing parts has a fan shape having the same central angle.
Further, in the present invention, the divided polishing portion has three groove groups, the first groove group is provided in parallel to the radial edge of the divided polishing portion, and the second groove group and the third groove group are: The present invention relates to the above polishing tool, which is formed so as to intersect at 60 ° and 120 ° with respect to the first groove group, respectively.
Furthermore, this invention relates to the said grinding | polishing tool whose formation of a groove | channel is by wire cut electric discharge machining.
The present invention also relates to the above polishing tool, which is a CMP pad conditioner.

Furthermore, the present invention is a method for manufacturing a polishing tool having a polishing portion made of a superabrasive sintered body,
(1) A step of sintering and integrating superabrasive grains to a cemented carbide backing material to obtain a superabrasive sintered body,
(2) a step of flattening a polishing portion of the obtained superabrasive sintered body,
(3) It is related with the said manufacturing method including the process of providing a linear groove group in the planarized super abrasive grain sintered compact, forming a some grinding | polishing unit, and setting it as a grinding | polishing part.
Further, the present invention is a method of manufacturing a polishing tool having a polishing portion made of a superabrasive sintered body,
(1) A step of sintering and integrating superabrasive grains to a cemented carbide backing material to obtain a superabrasive sintered body,
(2) A step of cutting out one fan-shaped divided polishing portion from the obtained superabrasive sintered body,
(3) A step of obtaining a plurality of fan-shaped divided polishing portions having a central angle equal to the fan-shaped divided polishing portion obtained in (2),
(4) A step of sticking the obtained fan-shaped divided polishing portions closely and adhering to a flat substrate surface to form a disk-shaped or annular polishing portion;
(5) The present invention relates to the above production method, comprising the step of forming a plurality of polishing units by providing a groove at the boundary between the divided polishing portions of the disc-shaped or annular polishing portion obtained in (4).
Furthermore, the present invention relates to the method for regenerating a polishing tool according to any one of the above, comprising the step of regenerating the grooves and the top of the polishing unit by wire-cut electric discharge machining.

  The polishing tool of the present invention uses a polishing portion made of a superabrasive sintered body, and is sintered at a temperature equal to or higher than the melting temperature of the binder, so that the superabrasive adhesion strength is large and substantially falls off. There is no advantage. Particularly when diamond particles are used as superabrasive grains, diamond is subjected to temperature and pressure conditions in which the binder metal is melted and the diamond is thermodynamically stable in the manufacturing process, and the diamond fine particles become the binder metal. Because of the strong integration through partial dissolution, the fixing strength is further increased, so that there is virtually no dropout.

  In general, when sintered in a large area, unevenness is generated, and it is difficult to produce a uniform polished portion with a large diameter as a whole, but it is difficult to produce a superabrasive sintered body from a plurality of divided polished portions of the present invention. Since the polishing tool to be manufactured is cut out from a small-diameter superabrasive sintered body that does not have uneven sintering, a large-diameter fan-shaped divided polishing part is combined, and a plurality of these are combined to make a large-diameter polishing part. It is possible to obtain a highly accurate polishing tool that is homogeneous throughout.

  Furthermore, the polishing part in which the polishing unit is formed is composed of a superabrasive sintered body having a sufficient thickness on the surface. The grooves and polishing units can be easily regenerated and reused as the tool of the present invention.

  In the present invention, each polishing unit is arbitrarily cut from a superabrasive sintered body such as a diamond sintered body by wire-cut electric discharge machining or the like, and has a bottom surface level and a high height such as a triangular pyramid and a quadrangular pyramid. Since the control of the thickness is easy, a tool having a polishing surface (level) with higher accuracy than that of a conventional polishing tool can be obtained. In particular, the surface of a semiconductor wafer or the like can be processed with high accuracy and high efficiency as a CMP pad conditioner.

It is explanatory drawing (plan view) which shows one embodiment of the polishing tool by this invention. (Example 1) It is explanatory drawing (plan view) which shows one embodiment of the polishing tool by this invention. (Example 2) It is explanatory drawing (plan view) which shows one embodiment of the polishing tool by this invention. It is explanatory drawing (plan view) which shows one embodiment of the polishing tool by this invention. It is the elements on larger scale of FIG. It is the elements on larger scale of FIG. It is explanatory drawing (plan view) which shows one structural example about the grinding | polishing unit of the grinding | polishing tool by this invention. It is explanatory drawing which shows the cross section in AA in FIG. It is explanatory drawing (plan view) which shows another structural example about the grinding | polishing unit of the grinding | polishing tool by this invention. It is explanatory drawing which shows the cross section in BB in FIG. It is explanatory drawing which shows the one aspect | mode of the wire cut electric discharge machining which can use the polishing tool by this invention in a manufacturing method. It is explanatory drawing (plan view) which shows one embodiment of the polishing tool by this invention. It is explanatory drawing (plan view) which shows one embodiment of the polishing tool by this invention. It is explanatory drawing (plan view) which shows one embodiment of the polishing tool by this invention. It is explanatory drawing (plan view) which shows one embodiment of the polishing tool by this invention. It is explanatory drawing (plan view) which shows one embodiment of the polishing tool by this invention. It is explanatory drawing (plan view) which shows one embodiment of the polishing tool by this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Polishing tool 2 Polishing unit 3 Groove 4 Polishing tool 5 Polishing unit 6 Groove 7 Polishing tool 8 Polishing unit 9 Groove 10 Polishing part 12 First direction parallel groove group 13, 14 Conical (table) side surface 16 Second direction parallel groove Group 17, 18 Cone inclined side surface 19 Square pyramid (conical) polishing unit 22 First direction parallel groove group 23, 24 Triangular pyramid inclined surface 25 Polishing part 27 Second parallel groove group 28, 29 Inclined side surface 31 Third direction parallel Groove group 32, 33 Inclined side surface 34 Triangular pyramid-shaped polishing unit 41 Wire for electric discharge machining 42 Polishing part 43, 44 Polishing unit 51 Polishing part 52 Circular substrate 53 Linear groove group 55 Second groove group 58 Peripheral inclined part 61 Polishing part 62 Circular substrate 63 Linear groove group 65 Second groove group 66 Third groove group 68 Peripheral inclined portion 69 Inner peripheral inclined portion 71 Polishing portion 72 Circular substrate 73 Linear groove group 74 Joint portion 75 Second groove group 81 Polishing portion 82 Circle Substrate 83 Linear groove group 84 Bonding portion 85 Second groove group 91 Polishing portion 92 Circular substrate 93 Linear groove group 94 Bonding portion 95 Second groove group 96 Third groove group 101 Polishing portion 102 Circular substrate 103 Linear groove group 104 Joining part 105 Second groove group 106 Third groove group

The superabrasive sintered body used as the material of the polishing tool of the present invention can be obtained by treating superabrasive powders such as diamond and c-BN (cubic boron nitride) in an ultrahigh pressure and high temperature process by a conventional method. Since the sintered body in this state has a large strain in the superabrasive sintered body, it is preliminarily flattened by die discharge machining or the like. Next, by forming the grooves and the side surfaces of the protrusions in a stepwise manner in a manner specified by the present invention, a polishing unit, that is, a protrusion portion that directly contacts the object to be polished is created. When a commercially available product is used as the superabrasive sintered body, although depending on the specifications, since the surface is flattened, the flattening pretreatment can be omitted.
For the formation of the groove, wire cut electric discharge machining, die electric discharge machining, other precision electric discharge machining, or laser machining can be used, but wire cut electric discharge machining is preferable, and in particular, the top of the polishing unit is sharply sharpened. For example, wire-cut electric discharge machining is particularly preferable. Wire cutting is a technique that drives a wire for electric discharge machining along the surface of the superabrasive sintered body and removes the material by electric discharge between the metal wire and the superabrasive sintered body material. Is done.

  In the polishing tool of the present invention, the polishing unit is, for example, a plurality of groove groups for dividing the polishing surface into circular or sintered annular layers having concentric central circular holes (hereinafter also referred to as divided groove groups). Can be created by crossing and cutting, or by die-discharge machining using an electrode having an electrode surface formed in a corresponding shape. Regardless of whether the dividing groove group is formed on the surface of the superabrasive layer or the electrode surface, it is easy to form a straight groove.

The said division groove group can be arrange | positioned variously. As an example, on the circular surface of the superabrasive layer, two sets of parallel straight line groups extending from the outer periphery to the opposite outer periphery are formed so as to be orthogonal to each other (FIG. 1). There are three sets that intersect at 60 ° (Fig. 2). In these cases, square or triangular polishing units are created, respectively.
Further, the polishing unit has a shape that forms a linear ridge line at the top (FIG. 3; the polishing unit has a ridge line from end to end of the polishing unit, FIGS. 4 to 5; the base of the polishing unit is rectangular), etc. Also good. When the polishing unit is rectangular, the groove and the inclined surface of the adjacent polishing unit are formed by wire-cut electric discharge machining, so that the ridge line is basically formed parallel to the long side. Further, the quadrangular pyramid-shaped polishing units do not necessarily have equal vertical and horizontal pitches, but a square is preferable as the CMP conditioner.

  In the above example, in order for each polishing unit to function as an effective polishing portion, the top of each polishing unit must be sufficiently small, and adjacent polishing units must be separated from each other with sufficient spacing. It is. As an example of the area of the top of the polishing unit, FIG. 6 schematically shows a partially enlarged explanatory view of the polishing tool 1 of FIG. 1. For example, the area (X) of the base of the polishing unit 2 (ie, the superabrasive layer The ratio of the top area (Y) to the area obtained by subtracting the area of the groove 3 around the polishing unit from the area of the cross section is preferably 50% or less, particularly preferably 2 to 25%. The apex angle of the top of the polishing unit is preferably 30 to 120 °, particularly preferably 60 to 90 °, and more preferably about 70 to 80 °.

  The depth of the groove (the height of the polishing unit from the groove bottom) is suitably 0.1 mm or more and 1 mm or less, particularly 0.15 mm or more and 0.3 mm or less. When the groove is too shallow, the shavings of the work material are not efficiently discharged, and the polishing resistance tends to be excessively increased. On the other hand, if it is too deep, the strength of the polishing unit is insufficient, and an excessive superabrasive layer thickness is required.

The polishing unit should be formed as a linear or line-shaped, triangular, quadrangular or more polygonal column at the top, with each side being perpendicular to the substrate and having a horizontal cross section that is uniform over the entire height. However, sharpness can be improved by inclining at least one side, particularly the front side with respect to the direction of rotation of the tool, backward with respect to the plane parallel to the axis.
As the shape of the polishing unit, it is preferable that each side surface of the polishing unit is inclined to form a frustum shape, for example, a quadrangular frustum shape or a triangular frustum shape. Further, for example, a quadrangular pyramid shape or a triangular pyramid shape having a pointed apex is particularly preferable in terms of sharpness.
Further, in an aligned prismatic or pyramidal polishing unit, one or a plurality of directions of a rectangle or a triangle is polished with a dedicated tool to sharpen the top edge or vertex, so-called “blading” is performed. And even better sharpness can be achieved. In particular, when the polishing unit is a polygonal column or a polygonal frustum, and the top is a polygon (typically a triangle or a quadrangle), cutting is performed on at least one side of the top surface. In the case of a quadrangular pyramid shape or a triangular pyramid shape, a sufficient sharpness can be achieved without cutting.

  The polishing portion of the present invention is configured so that the outer diameter is 90 mm or more and the superabrasive layer thickness is 0.1 mm or more and 1 mm or less. As a sintered superabrasive layer, one surface of a diamond sintered body (PCD) or c-BN sintered body (PcBN) is cemented with a cemented carbide, that is, a tungsten carbide based composite material, or a group 6a metal of the periodic table. The composite material is composed of a composite material block consisting mainly of carbides, and the composite material side is fixed to the tool substrate with an adhesive or the like, and a division groove is formed on the opposite side to be used as a polishing portion.

  As such a sintered body, a disk-shaped one typically prepared by a uniaxial pressurization type high temperature ultrahigh pressure isostatic press is commercially available. When a sintered body having a target diameter is not available, or when strict flatness is not particularly required, the polishing tool of the present invention may be prepared for each part and assembled and used in one polishing tool.

  When the polishing unit is composed of a plurality of divided polishing units, it is appropriate to form grooves at the boundary between the divided polishing units in order to obtain an arrangement in which the polishing units are evenly aligned as much as possible in the entire polishing unit. It is. At this time, if two sets of parallel grooves intersecting each other at right angles are formed in the two or four divided polishing portions and the polishing unit is a quadrangular pyramid or a truncated pyramid, the polishing unit is free from disturbance except for the outer peripheral portion. Alignment is obtained. On the other hand, in the case of a three- or six-part divided polishing section, three sets of equally spaced parallel straight lines intersecting each other at 120 ° are formed, and three pyramid side surfaces are formed to form a triangular pyramid or triangular frustum The same applies to the shape of the polishing unit row.

  That is, in the case of a quadrangular pyramid, a wire for electric discharge machining is sent along the surface of the polishing part, and a linear groove is first formed on the surface of the polishing part by electric discharge. Next, the side surface of the cone-shaped body adjacent to the groove is created by driving the wire in the Z-axis direction of the polishing portion and cutting the polishing portion along the side surface contour of the quadrangular pyramid. By repeating this operation, parallel groove groups are formed.

  In the present invention, the top of the cone is composed of one or more diamond particles. Even with fine particles, diamond has a finite size, so a cone in the geometric sense cannot be obtained. Therefore, when the top diameter is sufficiently smaller than the bottom, this is called a cone. As is obvious, the frustum refers to a case where the size of each apex is larger than that of the cone.

  In the production of a quadrangular pyramid (pedestal) -shaped polishing unit, for example, as shown in FIGS. 7 and 8, a group of parallel grooves (one of them) in the first direction 11 at a constant groove interval (pitch) on the surface of the polishing portion 10. Is representatively indicated by reference numeral 12. The same applies to the following, and both sides of the cone-shaped body (one representatively indicated by reference numerals 13 and 14, and the same applies hereinafter), and then the substrate to which the polishing portion 10 is fixed. Rotate 90 ° around the center axis of each ring, and in the same way, form parallel groove groups 16 in the second direction 15 at constant groove intervals and conical inclined side surfaces 17 and 18 adjacent to each groove. As a result, two sets of parallel grooves orthogonal to each other and a quadrangular pyramid (table) -shaped polishing unit 19 aligned along the grooves are obtained. A cross-sectional view taken along the line AA in FIG. 7 is shown.

  In the case of a triangular pyramid, as shown in FIGS. 9 and 10, in the above, after forming the parallel groove group 22 in the first direction 21 and the inclined surfaces 23 and 24 of the pyramids adjacent to the groove, the polishing unit 20 is Rotating 120 ° around the central axis of the polishing portion 25, the parallel groove group 27 in the second direction 26 and the adjacent inclined side surfaces 28 and 29 are similarly formed by wire-cut electric discharge machining at a constant groove interval. After the operation is completed, the polishing unit is further rotated by 120 ° to perform the same operation, whereby parallel groove groups 31 in the third direction 30 intersecting at 120 °, and adjacent inclined side surfaces 32 and 33, triangles aligned along the groove. A conical polishing unit 34 is obtained.

  In the above polishing unit, it is appropriate that the protrusion height of the top of the cone or frustum to the groove bottom is 200 μm or less and 30 μm or more for both the triangle and the quadrangle. If the protrusion is too shallow, the polishing section main body comes into direct contact with a work such as a pad and conditioning tends not to be performed effectively. On the other hand, if it is too large, the strength of the polishing unit is insufficient, or an excessive superabrasive layer thickness is required. On the other hand, the interval (pitch) between adjacent grooves is 1500 μm or less, and the lower limit depends on the diameter of the wire-cut electric discharge machining wire used, but can be, for example, about 200 μm.

  The polishing performance of the polishing unit depends on the particle size of the superabrasive grains contained at the top of the cone-shaped body. When the superabrasive grains are diamond particles, that is, when the sintered body constituting the polished portion is a sintered diamond (PCD) layer, the diamond particle size (nominal particle size) is 40-60 μm or less, 8-16 μm PCD layers of various particle sizes such as 0-2 μm can be used, but nominal particle sizes of 8-16 μm or less are preferred, with 0-2 μm being particularly preferred.

The diamond sintered body that can be used in the polishing portion of the present invention comprises diamond particles, a cemented carbide as a backing material, and optionally a binder metal such as cobalt, and diamond is thermodynamically stable at high pressure and high temperature. Obtained by subjecting to conditions. Processing from the sintered body to the polishing portion of the present invention can be realized by precision electric discharge machining, typically cut out by wire cut electric discharge machining, and formation of a polishing unit by surface processing. In wire-cut electrical discharge machining, in general, an electrical discharge machining wire is brought into contact with the superabrasive sintered body and discharged, and the wire is moved horizontally to obtain a desired groove width, and further, the side surface of the polishing unit is formed. Move as you do.
As shown in FIG. 11, after the electric discharge machining wire 41 is applied to the superabrasive sintered body 42, it is moved in the direction of the arrow in the figure without moving horizontally, and the adjacent polishing units 43, 44 are moved. It is also possible to form a groove so that the two inclined surfaces facing each other become the contact surface of the wire 41, and use this level as a reference surface, from which the side surfaces on both sides can be formed. When the groove is formed in this way, the shape of the bottom of the groove is a curved surface having a substantially arc-shaped cross section, and stress concentration during polishing is reduced compared to the case where the bottom of the groove is flat or square, and the strength of the polishing unit ( Durability).

  The tool of the present invention can be manufactured in several shapes as illustrated in FIGS. For relatively small tools, for example, the polishing portion can be made in a single continuous circle and an annular shape as illustrated in FIGS. 12 and 13, but in the present invention, as shown in FIGS. Since the polishing portion can be configured with a plurality of divided polishing portions without problems, an annular polishing portion having a large outer diameter of 95 mm or more can be easily obtained particularly in these cases.

  In an annular configuration, the radial width is preferably 15 mm or more. In particular, when the central hole is not required in the design, the polishing portion can be formed in a disc shape instead of an annular shape (having no central hole). Also, as shown in FIGS. 12 and 13, in order to prevent damage to the workpiece due to contact with the sharp edges, in the case of a circular polishing part, on the outer periphery and the inner peripheral part in an annular polishing part, It is preferable to provide the inclined portions 58, 68 and 69 over 1 mm or more (radial width).

  When the polishing unit is constituted by a plurality of divided polishing units, as illustrated in FIGS. 14 to 17, the polishing units are arranged so that a boundary portion (joint portion) between two adjacent polishing units becomes a groove. By setting the above, it is possible to avoid or minimize the disturbance of the polishing unit arrangement due to the divided configuration of the polishing part and the adverse effect on the workpiece (polishing pad) accompanying the disorder. At this time, the number of divisions of the polishing portion and the shape of the polishing unit that can be used are related to each other, and a quadrangular pyramid shape (see FIG. 14 and FIG. In FIG. 15), the three-part (center angle 120 °) polishing portion has a triangular pyramid shape (FIGS. 16 and 17).

In order to produce a large-diameter polishing tool, a small-diameter superabrasive sintered body (preferably a diamond sintered body) capable of uniform sintering is cut and processed into a predetermined size and shape. The formed divided polishing part is prepared. And, by joining a plurality of divided polishing parts to a flat disk surface or an annular surface of a rigid substrate made of various steels using an adhesive or the like, a large-diameter disk shape or an annular shape A polishing portion (a shape having a concentric circular hole in the center of the disc) can be obtained.
For the division polishing part, it is used by placing six, four, three, or two fan shapes with central angles of 60, 90, 120, 180 ° adjacent to each other on the radius side by side (side contact arrangement) However, instead of using two identical shapes for 60 ° ones, one 120 ° one can be substituted. In this case, the 120 ° ones are arranged symmetrically with respect to the center.

  Each polishing part 51, 61, 71, 81, 91, 101 joins the cemented carbide side to the flat circular surface of the circular substrate 52, 62, 72, 82, 92, 102, and is generally circular or annular. Present a polished part.

  The superabrasive sintered body bonded to the substrate is then subjected to wire-cut electric discharge machining, and the surface of the superabrasive sintered body is subjected to a discharge process between the wire-cut electric discharge machining wire and the superabrasive sintered body. A set of linear groove groups 53, 63, 73, 83, 93, 103 parallel to each other at regular intervals is formed. At this time, the wire is driven parallel to the substrate surface or the substrate bottom surface, enters the sintered body layer (typically, a sintered diamond (PCD) layer) from the pre-planarized surface, and is fired. If the sintered body layer is thin, the inside of the consolidated layer is further carved up to the cemented carbide layer.

  At this time, the wire is driven and cut in the thickness direction (Z-axis direction) of the superabrasive sintered body to produce a groove. The first groove formation in one groove group can be started from any position in the case of either a triangular pyramid or a quadrangular pyramid on a 360 ° continuous circular or annular surface, but there are multiple polishing parts. In the case of a combination of divided polishing parts, the joints 54, 64, 74, 84, 94, 104 of the divided polishing parts are always provided with grooves, and then formed on both sides in parallel at a constant pitch over the entire surface. I will do it.

  When parallel groove groups in one direction are formed on the surface of the superabrasive sintered body, the superabrasive sintered body is then rotated together with the substrate around the central axis of the substrate by a groove group crossing angle α, Similarly, the second linear parallel groove group 55, 65, 75, 85, 95, 105 and the inclined side surface adjacent to each groove are formed at the predetermined intervals. Here, α is 90 ° for a sector of 180 ° and 90 °, and the polishing unit has a quadrangular pyramid shape or a frustum shape. On the other hand, for 120 ° and 60 ° fan shapes, after rotating by 60 (or 120) °, similarly, after forming the second linear parallel groove group and the inclined side surface adjacent to each groove at the above-mentioned fixed intervals, Rotate another 60 (or 120) degrees (240 degrees relative to the first groove group) to form a third linear parallel groove group 56, 66, 76, 86, 96, 106 and an inclined side surface adjacent to each groove To do. For continuous circular and annular materials, α can be either 90 ° or 60 °.

  In the wire cut discharge operation, the discharge wire is driven at a height (level) equally spaced from the bottom surface of the substrate in the thickness direction, whereby the groove group and the top of the triangular or quadrangular pyramid or frustum-shaped body are formed on the substrate. It can be formed on a level parallel to the bottom surface.

In the present invention, the triangular pyramid or the quadrangular pyramid of the polishing unit does not necessarily need to be entirely composed of a superabrasive sintered body, and a portion (height) of about 60 μm including at least the apex of the cone (table) -like body. If is a superabrasive sintered body, it can be used even if the lower part is a cemented carbide. Next, the present invention will be specifically described with reference to examples.
[Example 1]

A polishing tool 1 having the structure schematically shown in FIG. 1 was prepared. A PCD block having a diameter of 90 mm, in which a sintered diamond layer having a thickness of 0.6 mm is integrated with the cemented carbide by simultaneous sintering, was used as a tool material.
In the PCD block, the surface of the sintered diamond layer is flattened by electric discharge machining (EDM), and a polishing unit 2 having a square apex having a side of 260 μm is formed by wire-cut electric discharge machining, and parallel linear grooves 3 having a width of 560 μm are formed. Formed by engraving. In this case, the area of the top portion (not shown) of the polishing unit 2 corresponds to about 10% of the cross-sectional area of the superabrasive sintered layer excluding the peripheral portion (the groove 3 portion).
The edge of the top was bladed and used as a CMP conditioner.
[Example 2]

An annular polishing tool 4 schematically shown in FIG. 2 was prepared. From a PcBN block in which a sintered c-BN layer with a thickness of 0.6 mm is integrated with cemented carbide by simultaneous sintering, a 90 degree fan shape with an outer radius of 60 mm and an inner radius of 24 mm is obtained by wire-cut electric discharge machining. 4 were cut out and used as a tool material.
The fan shape was attached to a substrate made of SUS stainless steel and combined into a complete circle. The surface of the sintered diamond layer was polished and flattened, and a polishing unit 5 having a regular triangular apex having a side of 350 μm was formed by a group of parallel linear grooves 6 having a width of 560 μm by wire-cut electric discharge machining. In this case, the area of the top of the polishing unit is 7% of the entire superabrasive sintered layer.
The obtained tool was bladed by the same operation as in Example 1 and used for polishing the surface of the silicon wafer.
[Example 3]

A polishing tool having the structure schematically shown in FIG. 12 was prepared. Using a diamond sintered body with a diameter of 100 mm as a polishing part, in which a 0.5 mm thick PCD layer consisting of diamond particles with a nominal particle size of 40-60 μm is integrated with cemented carbide (WC-8% Co) by simultaneous sintering The SUS316 stainless steel circular substrate having a diameter of 108 mm was fixed with an epoxy adhesive.
Next, the surface of the PCD layer was flattened by mold electric discharge machining, and then cut into the PCD layer by wire cut electric discharge machining to form a linear groove having a width of 200 μm passing through the center of the material. Further, the wire was driven to the side and moved in a direction away from the substrate (Z direction) to form a groove having a necessary width and cut out the side surface of the cone.
By repeating this operation, parallel groove groups having a groove interval of 800 μm and roof-like protrusions having a vertex angle of 90 ° were formed on the entire material surface.
Next, after rotating the whole 90 ° around the central axis, wire-cut electric discharge machining is performed under the same conditions to form a second linear groove group orthogonal to the above groove group and at the same time orthogonal The side surfaces of the cones were cut out to form a group of quadrangular pyramids as shown in FIGS. 7 and 8 having a height of 200 μm.
[Example 4]

The operation of Example 3 was carried out using a diamond sintered body having an outer diameter of 100 mm and an inner diameter of 70 mm as a polishing part, in which a 0.5 mm thick PCD layer composed of diamond particles having a nominal particle size of 0-2 μm was integrated with a cemented carbide. Repeatedly, a polishing tool having a quadrangular pyramidal polishing unit was produced.
First, the surface of the flattened PCD layer was wire cut electric discharge processed to form a straight groove having a width of 140 μm passing through the center of the material. Further, the necessary groove width was expanded and the side surfaces of the cones were cut out by operating the wires. By repeating this, a parallel groove group with a groove interval of 200 μm and a roof-like protrusion with a vertex angle of 60 ° were formed on the entire material surface.
Next, after rotating the whole around the central axis by 90 °, the second linear groove group is formed by performing wire-cut electric discharge machining under the same conditions, and simultaneously cutting out the side surface of the second cone A quadrangular pyramid group having a height of 200 μm was formed.
[Example 5]

  Using various divided polishing portions shown below, tools having respective configurations were produced. All diamonds in the diamond sintered body have a nominal particle size of 20-30 μm. The wire cutting operation is essentially different for triangular pyramid polishing units, except that the tool material is rotated twice by 60 °, except for a square pyramid polishing unit that rotates 90 ° only once. Don't be. The operating conditions and results are shown in the following table.

  All of the obtained tools were used as CMP pad conditioners, and good performance was obtained.

  Although the polishing tool of the present invention can be used as various polishing tools, it can be suitably used particularly as a disk-type rotary polishing tool. As an application, it is particularly suitable for use as a CMP pad conditioner, and also suitable for directly polishing the surface of a semiconductor wafer or the like. In addition to these, it can be applied to high-precision polishing of various work materials.

Claims (24)

A polishing tool having a polishing portion made of a superabrasive sintered body,
Polishing portion comprises a plurality of polishing units having a top, the top portion Ri near substantially the same plane with each other,
The polishing part is composed of a superabrasive sintered body obtained by sintering and integrating superabrasive grains together with a binder metal together with a cemented carbide backing material, and the polishing unit is linearly connected to the polishing part by wire-cut electric discharge machining. The polishing tool, which is formed by providing a groove group .   The polishing tool according to claim 1, wherein the top is bladed.   The polishing tool according to claim 1, wherein the polishing unit is a quadrangular pyramid or a truncated pyramid. The polishing tool according to claim 3 , wherein the polishing unit is a truncated pyramid shape, and at least one side of the top is bladed.   The polishing tool according to claim 1, wherein the polishing unit is a triangular pyramid shape or a triangular frustum shape. The polishing tool according to claim 5 , wherein the polishing unit has a triangular frustum shape, and at least one side of the top is bladed.   The polishing tool according to claim 1, wherein the polishing unit has a shape exhibiting a linear ridge line at the top. The polishing tool according to any one of claims 1 to 6 , wherein the polishing unit is a quadrangular pyramid shape or a triangular pyramid shape, and a pitch of the polishing unit is 1500 µm or less and 200 µm or more. The polishing tool according to claim 8 , wherein the polishing unit is a quadrangular pyramid or a triangular pyramid, and the height of the polishing unit is 200 μm or less and 30 μm or more. The polishing tool according to any one of claims 1 to 9 , wherein the superabrasive grains are diamond. The polishing tool according to claim 10 , wherein the diamond has a nominal particle size of 40 to 60 μm or less. The polishing tool according to any one of claims 1 to 11 , wherein the superabrasive sintered body has a thickness of 0.1 mm or more. The polishing tool according to any one of claims 1 to 12 , which has a disc shape or an annular shape. The polishing tool according to claim 13 , wherein the polishing portion is disk-shaped or annular. The polishing tool according to claim 14 , wherein an outer diameter of the polishing portion is 90 mm or more. The polishing tool according to any one of claims 2 to 15 , wherein a height of a top portion with respect to a groove bottom of the polishing portion is 1 mm or less. The polishing tool according to any one of claims 13 to 16 , wherein the polishing portion is composed of two or four divided polishing portions, and each of the divided polishing portions has a fan shape having an equal central angle. The divided polishing portion has two groove groups, the first groove group is provided parallel to the radial edge of the divided polishing portion, and the second groove group is formed orthogonal to the first groove group. The polishing tool according to claim 17 . The polishing tool according to any one of claims 13 to 16 , wherein the polishing portion includes three or six divided polishing portions, and each of the divided polishing portions has a fan shape having an equal central angle. The divided polishing portion has three groove groups, the first groove group is provided in parallel to the radial edge of the divided polishing portion, and the second groove group and the third groove group are respectively the first groove group. The polishing tool according to claim 19 , wherein the polishing tool is formed to intersect at 60 ° and 120 °. The polishing tool according to any one of claims 1 to 20 , which is a CMP pad conditioner. A method for producing a polishing tool having a polishing portion made of a superabrasive sintered body,
(1) A process of obtaining superabrasive sintered body by superimposing superabrasive grains together with a binder metal and superabrasive grains on a backing material of cemented carbide, and integrating the superabrasive grains.
(2) a step of flattening a polishing portion of the obtained superabrasive sintered body,
(3) The said manufacturing method including the process of providing a linear groove group in the superabrasive grain sintered body planarized by wire cut electric discharge machining, forming a some grinding | polishing unit, and setting it as a grinding | polishing part. A method for producing a polishing tool having a polishing portion made of a superabrasive sintered body,
(1) A process of obtaining superabrasive sintered body by superimposing superabrasive grains together with a binder metal and superabrasive grains on a backing material of cemented carbide, and integrating the superabrasive grains.
(2) A step of cutting out one fan-shaped divided polishing portion from the obtained superabrasive sintered body,
(3) A step of obtaining a plurality of fan-shaped divided polishing portions having a central angle equal to the fan-shaped divided polishing portion obtained in (2),
(4) A step of sticking the obtained fan-shaped divided polishing portions closely and adhering to a flat substrate surface to form a disk-shaped or annular polishing portion;
(5) including a step of forming a plurality of polishing units by providing a groove by wire-cut electric discharge machining at a boundary between the divided polishing portions of the disk-shaped or annular polishing portion obtained in (4), Production method. The method for regenerating a polishing tool according to any one of claims 1 to 21 , comprising a step of regenerating the groove and the top of the polishing unit by wire-cut electric discharge machining.

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