Diamond disc and method of manufacturing the same

Abstract

The diamond disc of the present invention includes a stem base, a bonding layer formed on the surface of the stem base, and a plurality of boron-doped diamonds exposed to the bonding layer, at least a portion of the plurality of boron-doped diamonds being disposed on the bonding layer in a posture in which the boron-doped diamonds are disposed in a posture in which at least a portion of the plurality of boron-doped diamonds is disposed in a posture in which at least a portion of the plurality of boron-doped diamonds is disposed in a posture in which at least a portion of the plurality of boron-doped diamonds is disposed in a posture in which at least a portion of the plurality of boron-doped diamonds is disposed in a posture in which at least a portion of the plurality of boron-doped diamonds is disposed in a posture in which at least a portion of the plurality of boron-doped diamonds is disposed in a posture in which at least a portion of the plurality of boron-doped diamonds is

Description

Technical Field

[0001] This invention relates to a diamond disc and its manufacturing method. Background Technology

[0002] Typically, CMP (Chemical Mechanical Polishing) is a chemical-mechanical polishing process that achieves flatness of semiconductor wafers by simultaneously using polishing removal processes and the dissolving effect of chemical solutions.

[0003] The principle of CMP polishing is to move the polishing pad and the wafer relative to each other under mutual pressure, and to supply polishing slurry, a mixture of polishing particles and chemical solution, to the polishing pad. At this time, the numerous foam pores on the surface of the polishing pad, which is made of polyurethane material, play a role in accommodating the new polishing slurry, thereby achieving a certain polishing efficiency and polishing uniformity on the entire wafer surface.

[0004] However, due to the increased pressure and relative speed during polishing, the surface of the polishing pad undergoes uneven deformation over time, and the pores on the polishing pad become clogged with polishing residue, preventing the polishing pad from functioning properly. Therefore, it is impossible to achieve large-area planarization across the entire wafer surface and uniform polishing between wafers throughout the overall processing time.

[0005] To address the issues of uneven deformation and pore blockage in CMP polishing pads, a CMP pad adjuster is used to adjust the CMP pads and perform fine polishing on the surface of the polishing pads to create new micropores.

[0006] CMP pad conditioning can be performed simultaneously with CMP operations for key productivity-enhancing tasks. This is known as in-situ conditioning.

[0007] At this point, the polishing slurries used in CMP operations include polishing particles such as silica, alumina, or cerium dioxide. Furthermore, CMP processes are broadly classified into oxide CMP and metal CMP based on the type of polishing slurry used. The former uses oxide CMP slurries with a pH value primarily between 10 and 12, while the latter uses metal CMP slurries that are acidic solutions with a pH value less than or equal to 4.

[0008] Conventional existing CMP pad conditioners include electrodeposited CMP pad conditioners manufactured by electrodeposition and fused CMP pad conditioners manufactured by melting metal powder at high temperatures. These CMP pad conditioners primarily use granular diamond particles as a polishing agent. The diamond particles are fixed by a metal matrix formed by electrodeposition or fusion.

[0009] Diamonds are known as the hardest material on Earth. Due to these properties, diamond tools made from synthetic diamonds are manufactured and used.

[0010] However, in existing CMP processes, the diamonds in the CMP pad conditioner are used together with the polishing slurry for wafer polishing. If a highly corrosive polishing slurry is used, the additives in the slurry can react with the carbon in the diamond, potentially accelerating diamond wear and shortening the lifespan of the diamond pad.

[0011] (Existing technical literature)

[0012] (Patent Document) Korean Patent Publication No. 10-2012-0058303 Summary of the Invention

[0013] Technical problems to be solved

[0014] The embodiments of the present invention aim to provide a diamond disc with improved wear resistance and high polishing performance, and a method for manufacturing the same.

[0015] Problem-solving methods

[0016] According to one aspect of the present invention, a diamond disc may be provided, including a shank base; a bonding layer formed on the surface of the shank base; and a plurality of boron-doped diamonds (BDDs) exposed on the bonding layer, at least a portion of the plurality of boron-doped diamonds being disposed on the bonding layer in an arrangement intersecting the long axis of the boron-doped diamonds, with the uppermost face inclined downward from the upper end of the long axis.

[0017] Furthermore, the long axis of the boron-doped diamond has an orientation of greater than 50° and less than or equal to 90° relative to the shank base, and the boron-doped diamond can be disposed on the bonding layer.

[0018] Furthermore, the wetting angle at which the surface of the bonding layer intersects the surface of the boron-doped diamond can be maintained at greater than or equal to 0° and less than or equal to 60°.

[0019] Furthermore, the ratio of the thickness of the bonding layer to the average diameter of the boron-doped diamond can be in the range of 30% to 65%.

[0020] Furthermore, the amount of boron doping in the boron-doped diamond can be in the range of 1 ppm to 2000 ppm.

[0021] Furthermore, the magnetic susceptibility per unit volume of the boron-doped diamond can be in the range of 20 to 800 per unit volume.

[0022] Furthermore, the ratio of the density of the boron-doped diamond to the density of the bonding layer can be maintained in the range of 0.4 to 0.6.

[0023] Furthermore, the boron-doped diamond is an octahedron diamond. When the boron-doped diamond is placed on the upper part of the bonding layer, the lower end of the boron-doped diamond can make point contact, line contact, or be spaced at a predetermined distance from the surface of the shank base.

[0024] Furthermore, the pad cut rate (PCR) of the boron-doped diamond is as follows: in a PCR testing device, when the CMP pad (Pad) regulator made of the boron-doped diamond rotates at a speed of 100 rpm to 120 rpm and the polishing pad rotates at a speed of 80 rpm to 95 rpm, under the condition that the CMP pad regulator made of the boron-doped diamond applies a pressure of 4.5 to 9 lbf to the polishing pad, it takes more than 13 hours to reduce the PCR rate to 2 to 10 μm / hr for pad conditioning.

[0025] According to one aspect of the present invention, a method for manufacturing a diamond disc is provided, comprising the following steps: a bonding material coating step, wherein a bonding material is coated onto the surface of a stem base; a pre-sintering step, wherein the bonding material coated on the surface of the stem base is heated to a first temperature range to form a bonding layer in the form of a pre-sintered body; a diamond providing step, wherein a plurality of boron-doped diamonds (BDDs) are provided on the surface of the pre-sintered body; and a heat treatment step, wherein at least a portion of the plurality of boron-doped diamonds is heat-treated in a second temperature range such that at least a portion thereof is disposed on the bonding layer in an orientation intersecting the long axis of the boron-doped diamonds, with the uppermost face inclined downward from the upper end of the long axis.

[0026] Furthermore, in the heat treatment step, the long axis of the boron-doped diamond can be exposed and placed in the bonding layer at an angle of greater than 50° and less than or equal to 90° relative to the shank base.

[0027] Furthermore, in the pre-sintering step, the first temperature range is 600°C to 900°C, and in the heat treatment step, the second temperature range can be 1000°C to 1300°C.

[0028] Furthermore, in the heat treatment step, the wetting angle at which the surface of the bonding layer intersects the surface of the boron-doped diamond can be maintained at greater than or equal to 0° and less than or equal to 60°.

[0029] Furthermore, in the heat treatment step, the ratio of the thickness of the bonding layer after heat treatment to the average diameter of the boron-doped diamond can be in the range of 30% to 65%.

[0030] The effects of the invention

[0031] According to embodiments of the present invention, the present invention has the advantage of achieving excellent wear resistance and high polishing performance through boron-doped diamond (BDD) with an octahedral structure.

[0032] Furthermore, according to embodiments of the present invention, since the present invention is an octahedral boron-doped diamond (BDD), and the proportion of self-standing boron-doped diamond is greater than a certain proportion, it has the advantages of improving wear resistance and polishing performance.

[0033] Simple Explanation of the Diagram

[0034] Figure 1 This is a diagram showing the state in which boron-doped diamond (BDD) is temporarily attached to the bonding layer in the form of a pre-sintered body in a diamond disk according to an embodiment of the present invention.

[0035] Figure 2 This is a diagram showing the state in which boron-doped diamond (BDD) on a heat-treated bonding layer stands upright in a diamond disk according to an embodiment of the present invention.

[0036] Figure 3 This is a diagram showing the wetting state of boron-doped diamond (BDD) on a heat-treated bonding layer in a diamond disk according to an embodiment of the present invention;

[0037] Figures 4 to 5 These are comparative photographs showing the wear and tear of a diamond disc and a regular diamond according to an embodiment of the present invention;

[0038] Figure 6 This is an enlarged comparison diagram showing a diamond disk using boron-doped diamond (BDD) and a diamond disk using undoped ordinary octahedral diamond according to an embodiment of the present invention.

[0039] Figure 7 This is a PCR test chart showing the relationship between boron-doped diamond (BDD) and a diamond disk using ordinary octahedral diamond according to an embodiment of the present invention.

[0040] Figure 8 This is a graph showing the rate of weight reduction with heat treatment in boron-doped diamond (BDD) and regular diamond according to an embodiment of the present invention;

[0041] Figure 9 This is a block diagram illustrating a method for manufacturing a diamond disc according to an embodiment of the present invention. Detailed Implementation

[0042] The specific embodiments for implementing the technical concept of the present invention will be described in detail below with reference to the accompanying drawings.

[0043] Furthermore, in the description of this invention, detailed descriptions of known configurations or functions will be omitted if it is determined that such detailed descriptions may obscure the gist of the invention.

[0044] Furthermore, when an element is described as being “connected,” “supported,” “connected,” “provided,” “communicated,” or “in contact” with another element, it can be understood that the element can be directly connected, supported, connected, provided, communicated, or in contact with another element, but there may also be other elements in between.

[0045] The terminology used herein is for illustrative purposes only and is not intended to limit the invention. Unless the context clearly specifies otherwise, singular expressions include plural expressions.

[0046] Furthermore, the descriptions of "top," "bottom," and "side" in this specification are based on the illustrations in the accompanying drawings. It should be noted beforehand that different expressions may be used when the orientation of the corresponding object changes. For the same reason, some elements in the drawings are exaggerated, omitted, or shown schematically, and the dimensions of each element do not necessarily reflect the actual dimensions.

[0047] Furthermore, various elements may be described using terms including ordinal numbers such as 1, 2, etc., but the corresponding elements are not limited by these terms. These terms are only used to distinguish one element from another.

[0048] The term "comprising" as used in this specification is intended to specifically describe certain features, regions, integers, steps, operations, elements, and / or components, but does not exclude the presence or addition of other specific features, regions, integers, steps, operations, elements, components, and / or combinations.

[0049] First, regarding the chemical composition of diamonds, when comparing regular diamonds and the boron-doped diamond (BDD) according to the present invention, in highly corrosive environments (such as WCMP, Oxide CMP processes), the wear resistance of boron-doped diamond (BDD) is superior to that of regular diamonds. In general environments with low corrosivity, there is no significant difference in wear resistance between regular diamonds and boron-doped diamond (BDD).

[0050] Furthermore, in the electrodeposition CMP diamond disc manufacturing method, nickel plating serves as a bonding layer supporting the non-conductive diamond. However, for conductive boron-doped diamond (BDD), the nickel electrodeposition layer is coated onto the surface of the boron-doped diamond during electroplating; therefore, boron-doped diamond produced by conventional methods cannot be used in the electrodeposition process. Consequently, boron-doped diamond (BDD) can be applied in the manufacture of diamond discs via fusion and sintering methods.

[0051] Furthermore, in the processing of general iron (Fe)-based metals, diamonds are difficult to process due to their affinity reaction with iron-based metals. During CMP pad conditioning operations, when polishing slurry is supplied to the polishing pad, the iron (Fe) component in the slurry may react with the carbon in the diamond on the diamond disk, thereby accelerating diamond wear. As a result, the diamond wears out faster and has a shorter lifespan. However, the boron-doped diamond (BDD) according to the present invention suppresses the carbon oxidation reaction (C + O2 → CO2) (acting as a blocking layer), thus improving the stability of the diamond disk.

[0052] The manufacturing differences of boron-doped diamond (BDD), ordinary diamond, and existing cubic boron nitride (CBN) according to the present invention are shown in Table 1 below.

[0053] [Table 1]

[0054]

[0055] In the boron-doped diamond according to the present invention, Fe, Ni alloy, and boron (pure boron or boron carbide) serve as catalysts. During diamond synthesis, boron can be substituted with carbon, or boron can infiltrate the diamond structure. This boron-doped diamond inhibits the reaction between external iron (Fe) and the carbon in the diamond, providing all the wear-resistant properties of the diamond.

[0056] On the other hand, ordinary diamonds use Fe and Ni alloys as carbon catalysts, but do not contain boron. Since boron nitride (CBN) has a structure with a carbon to boron content ratio of 1:1, the amount of boron added is relatively large. Therefore, although it does not react with iron (Fe), its strength is very low compared to boron-doped diamonds, and shape control may be difficult.

[0057] In this embodiment, the boron-doped diamond (BDD) used in the diamond disk may comprise 5 vol% or more of the total diamonds, depending on the intended use. Furthermore, the proportion of octahedral structures in the boron-doped diamond (BDD) may be greater than or equal to 50%. In all the boron-doped diamonds (BDD), the proportion of self-standing boron-doped diamonds in the bonding layer may be greater than or equal to 60%.

[0058] The proportion can be determined by observing all the diamonds in a certain area, which is the proportion of diamonds that meet the above criteria.

[0059] In the following text, reference will be made to Figures 1 to 8 The specific construction of a diamond disc according to an embodiment of the present invention is described.

[0060] refer to Figures 1 to 6 The diamond disc according to the present invention can be applied to a CMP pad conditioner to finely polish the surface of the polishing pad. The diamond disc may include a shank base 100, a bonding layer 200, and a plurality of boron-doped diamonds 300 (BDD).

[0061] Specifically, the handle base 100 is the backing plate of the disc, and the bonding layer 200 may be formed on the surface of the handle base 100. Since the handle base 100 corresponds to a conventional handle base 100 used as the backing plate of a disc, its detailed description will be omitted.

[0062] The bonding layer 200 contains 60 wt% or more Ni and may be made of a bonding material containing other elements such as Cr and Si. After the bonding material is applied to the surface of the shank base 100, it can be dried and pre-sintered to form a solid-phase pre-sintered body. An adhesive for temporarily attaching boron-doped diamond 300 can be applied to the upper surface of the pre-sintered body. A drilling jig can be used to temporarily attach boron-doped diamond 300 to the upper surface of the adhesive-coated pre-sintered body.

[0063] The pre-sintered body can be combined with boron-doped diamond 300 to form a bonding layer 200 through a heat treatment process. The bonding layer 200 can undergo a phase transition to a liquid state during high-temperature heat treatment, and the boron-doped diamond 300 can be disposed upright on the bonding layer 200. The bonding layer 200, with the boron-doped diamond 300 disposed upright, can then be cooled and dried.

[0064] The density of the bonding layer 200 can be 6 g / cm³. 3 Up to 8.3 g / cm 3Within a certain range. The density of boron-doped diamond 300 can reach 3.5 g / cm³. 3 Up to 3.6 g / cm 3 Within the specified range. In this embodiment, the density of the bonding layer 200 is 7.6 g / cm³. 3 The density of boron-doped diamond 300 is 3.54 g / cm³. 3 .

[0065] Furthermore, the density ratio of boron-doped diamond 300 to the density of the bonding layer 200 can be in the range of 0.4 to 0.6. If the ratio is greater than 0.6, the buoyancy of boron-doped diamond 300 is too low due to the density difference between the bonding layer 200 and the boron-doped diamond 300, and therefore boron-doped diamond 300 may be submerged in the bonding layer 200. If the ratio is less than 0.4, the buoyancy of boron-doped diamond 300 is too high due to the density difference between the bonding layer 200 and the boron-doped diamond 300, and boron-doped diamond 300 may float on the upper surface of the bonding layer 200 and may tilt horizontally.

[0066] Boron-doped diamond 300 can be produced by incorporating Fe, Ni alloys, and boron (pure boron or boron carbide) as a catalyst within carbon. For example, in boron-doped diamond 300, the carbon may contain Fe, Ni alloys, and 1 ppm to 2000 ppm of boron (pure boron or boron carbide). In the diamond structure, boron can be substituted by carbon, or boron can infiltrate into the diamond structure. The boron-doped diamond 300 provides wear resistance and high durability without reacting with external iron (Fe).

[0067] Boron-doped diamond 300 can have a toughness index (TI) of 20–50 and a temperature toughness index (TTI) of 14–45. The magnetic susceptibility (MS) per unit volume of boron-doped diamond 300 can be in the range of 20–800, more preferably in the range of 30–500.

[0068] In the synthesis of boron-doped diamond 300, Fe, Ni, and other elements used as catalysts are contained within the diamond as impurities. Generally, the amount of impurities increases proportionally with the increase in boron doping. If the MS value is less than 20, the boron doping amount is very low, and the effect of boron in improving corrosion resistance may be reduced. If the MS value exceeds 800, the boron doping amount increases, but due to the excessive incorporation of strongly magnetic metallic foreign matter such as Fe and Ni, the physical properties of the diamond may deteriorate, potentially leading to diamond particle breakage during CMP pad conditioning. As the amount of metallic foreign matter inside boron-doped diamond 300 increases, the TI and TTI values ​​also decrease, which can be observed through MS measurements. The diamond's toughness (TI, TTI, or MS) must be high enough to prevent cracking during prolonged use under CMP pressure.

[0069] Boron-doped diamond 300 can be an octahedron diamond. Diamonds can be synthesized into an octahedron shape according to the synthesis conditions. Octahedron diamonds have sharp edges, and in an octahedron diamond, the angle between the line connecting the vertex and the center and the face is 35° to 45°.

[0070] Multiple boron-doped diamonds (BDDs) 300 may be provided to be exposed to the bonding layer 200. At least some of the multiple boron-doped diamonds 300 may be positioned on the bonding layer 200 at an angle C of greater than 50° and less than or equal to 90° relative to the shank base 100 with their major axis L.

[0071] In this embodiment, an imaginary line connecting the two farthest vertices among the plurality of vertices of diamond 300 can be defined as an "axis." Among the plurality of "axes," the longest axis can be defined as the "major axis L." Furthermore, a "vertices" can be defined as the points where adjacent edges intersect. When adjacent edges do not intersect as "points" (e.g., when the portion corresponding to a vertex is obtuse), the imaginary point where the extended edges intersect when adjacent edges are extended can be defined as a vertex. Boron-doped diamonds with a major axis greater than or equal to 50° can be defined as self-standing.

[0072] Furthermore, the major axis L of the boron-doped diamond 300 has an angle C of greater than 50° and less than or equal to 90° relative to the shank base 100. The boron-doped diamond 300 being independently positioned on the upper part of the bonding layer 200 can be understood as self-standing. When the boron-doped diamond 300 is self-standing on the upper part of the bonding layer 200, the lower vertex of the boron-doped diamond 300 in the direction of its major axis can make point contact, line contact, or be spaced at a predetermined distance from the surface of the shank base 100.

[0073] When the major axis L of the boron-doped diamond 300 is at a 35° angle relative to the shank base 100, the boron-doped diamond 300 is in surface contact with the workpiece (polishing pad), and its polishing performance relative to the workpiece is significantly reduced. As the major axis L of the boron-doped diamond 300 approaches 90° relative to the shank base 100, the boron-doped diamond 300 makes point contact with the workpiece (polishing pad), thus significantly improving its polishing performance relative to the workpiece.

[0074] In order for the major axis L of the boron-doped diamond 300 to be positioned on the bonding layer 200 at an angle C greater than 50° and less than or equal to 90° relative to the shank base 100, the wetting angle (θ) between the surface of the boron-doped diamond 300 and the surface of the bonding layer 200 should be less than 90°, and preferably, the bonding layer assembly should be configured to be less than 60°.

[0075] refer to Figure 3 According to Formula 1 below, the wetting angle θ is determined by the upward force F. V Downward force F D and lateral force F L The vertical component is determined.

[0076] [Formula 1]

[0077] F V =F D +F L cosθ

[0078] When the wetting angle θ exceeds 90°, due to F L The vertical component is upward, therefore boron-doped diamond 300 can float more when the wetting angle θ is less than 90°, due to the lateral force F. L The direction of the vertical component will change to the lateral direction, so boron-doped diamond 300 will be subjected to a downward force.

[0079] For example, if the wetting angle θ is greater than 90°, the boron-doped diamond 300 may become buoyant, preventing the bonding layer 200 from properly supporting it, thus increasing the risk of the boron-doped diamond 300 falling off. Since no chip grooves are formed in the bonding layer to remove debris generated during polishing, proper chip removal is impossible, and polishing performance may significantly decrease. Preferably, when the wetting angle θ of the octahedral boron-doped diamond 300 is less than 60°, the boron-doped diamond 300 makes point or line contact with the workpiece (polishing pad), forming good chip grooves, which can significantly improve the polishing performance of the boron-doped diamond 300 relative to the workpiece.

[0080] However, even if the wetting angle between the boron-doped diamond 300 and the bonding layer 200 is less than 60°, if the bonding layer is too thick, the exposure height of the boron-doped diamond 300 in the bonding layer 200 will decrease, allowing the boron-doped diamond 300 and the workpiece to make surface contact through buoyancy. Furthermore, if the chip grooves for removing debris generated during polishing with the boron-doped diamond 300 are shallowly formed in the bonding layer 200, the removal of debris generated during polishing may be hindered.

[0081] Furthermore, when the wetting angle of boron-doped diamond 300 (BDD) is less than 60°, the boron-doped diamond 300 embeds itself more deeply into the bonding layer 200 under the influence of surface tension, thus reducing the height of the boron-doped diamond 300 protruding from the bonding layer 200. Therefore, the thickness of the bonding layer 200 must be strictly controlled to ensure the removal pathway for debris generated during the polishing of the diamond disk.

[0082] Furthermore, if the bonding layer 200 is thinner than appropriate, self-standing may occur due to buoyancy (density difference between the boron-doped diamond and the bonding layer) and wetting. In this case, the chip groove is well formed in the bonding layer 200, but if the thickness of the bonding layer 200 becomes too thin, the boron-doped diamond 300 may contact the shank base 100, and the boron-doped diamond 300 may further receive downward forces through surface tension. At this time, since the boron-doped diamond 300 is tilted flat, its exposure height in the bonding layer 200 is reduced, and the boron-doped diamond 300 may contact the workpiece surface. For example, when the diamond is flat and the long axis of the boron-doped diamond 300 is positioned on the bonding layer 200 at an angle C of approximately 35° to 45° with the shank base 100, the self-standing ratio of the boron-doped diamond 300 can be reduced.

[0083] The thickness of the bonding layer 200 according to the invention has a certain ratio to the average diamond particle size (diameter). For example, the ratio of the thickness of the bonding layer 200 to the average diameter of the boron-doped diamond 300 according to the invention can be in the range of 30% to 65%. [Table 2] is a table showing the angle-good diamond ratio (self-standing ratio) and PCR (Pad cut rate) for each height of the bonding layer 200. The diamond particle size is a mesh size with a certain range, and the average size of the diamond follows the ANSI standard. For example, the diamonds used in [Table 2] are #80 to #100, with an average size of 150 μm and a size range of 127 to 181 μm. The diamonds are distributed at 400 particles / cm. 2 The density is attached to a disc with a diameter of approximately 4”. The number of diamonds attached per unit area may vary depending on the average size of the diamonds.

[0084] [Table 2]

[0085]

[0086]

[0087] Referring to Table 2, when the bonding layer thickness is 68µm, 79µm, and 94µm, the diamond exposure height relative to the bonding layer thickness is relatively high, exhibiting the highest self-standing ratio, the highest angled diamond ratio, and the highest PCR. When the bonding layer thickness is 106µm, the diamond exposure height relative to the bonding layer thickness is also relatively low, the angled diamond ratio (self-standing ratio) is also low, and the PCR is also low. When the bonding layer thickness is 52µm, the diamond exposure height relative to the bonding layer thickness is relatively high, the angled diamond ratio (self-standing ratio) is slightly lower, and the PCR is also slightly reduced.

[0088] That is, since the PCR becomes very low when the ratio of the thickness of the bonding layer 200 to the average diameter of the boron-doped diamond 300 is 70% or more, the ratio should be managed to be below 70%. However, if the bonding layer 200 is too thin, there is a risk of diamond detachment even if the PCR value is maintained at a certain level; therefore, the thickness of the bonding layer 200 should be 30% or more of the average diamond size. Thus, the ratio of the thickness of the bonding layer 200 to the average diameter of the boron-doped diamond 300 is preferably in the range of 30% to 65%.

[0089] Figure 6 Cross-sectional photographs of boron-doped octahedral diamond 300 and ordinary octahedral diamond after heat treatment are shown. Even though ordinary diamond, which is not doped with boron and has an octahedron shape, has a lower PCR value than boron-doped diamond 300 (BDD) under the same conditions after a 15-minute PCR test in a PCR testing device. Blocky type diamonds, i.e., cube-octahedral diamonds, regardless of whether they are boron-doped, exhibit very low PCR values ​​in PCR tests under the same conditions as boron-doped diamond disks.

[0090] refer to Figure 7To measure the long-term PCR (Pad cut rate) of disks made of boron-doped diamond 300 and ordinary octahedral diamond, a PCR testing apparatus, polishing pads, a CMP pad conditioner, and polishing fluid are prepared. For example, the PCR testing apparatus can use a CMP polisher from CTS, the polishing pads can be 20" diameter IC1010 (DuPont) products, and the polishing fluid can be W7000 (Cabot Microelectronics). Furthermore, the CMP pad conditioner can be made of 4" diameter boron-doped octahedral diamond 300 and ordinary octahedral diamond.

[0091] When the PCR testing equipment, polishing pad, CMP pad conditioner, and polishing solution are prepared, the polishing pad is rotated at 80–95 rpm, and the CMP pad conditioner is rotated at 100–120 rpm. This allows the boron-doped diamond 300 or ordinary octahedral diamond of the CMP pad conditioner to apply a pressure of 4–9 lbf to the polishing pad. Under these conditions, the time taken for the PCR value to decrease to below the minimum PCR value due to pad conditioning is measured. If the PCR value is lower than the set value, the CMP pad conditioner is considered to be ineffective. At this point, the CMP pad conditioner can polish the polishing pad, simultaneously reciprocating 18–20 times per minute from the center to the edge of the polishing pad, supplying the polishing pad with 300 ml of polishing solution per minute.

[0092] Based on long-term PCR testing results, taking a CMP pad regulator equipped with ordinary octahedral diamond as an example, PCR requires 8 hours to reach 10 μm / hr, while a CMP pad regulator equipped with boron-doped diamond 300 has been shown to require 13 hours to reach 10 μm / hr. In the PCR tests described herein, for example, a CMP pad regulator requiring 13 hours to reach PCR 10 μm / hr, or a time exceeding 13 hours, is also within the scope of this invention. Since a longer time required for PCR to reach 10 μm / hr is more advantageous in a CMP pad regulator, no upper limit is specified herein; the time required for the CMP pad regulator to reach PCR 10 μm / hr may be 100 hours. Furthermore, even with a setting of, for example, 5 μm / hr or 2 μm / hr, it can be confirmed that boron-doped diamond 300 maintains pad polishing properties by 30% or more for a longer period compared to ordinary octahedral diamond.

[0093] Figure 4 and Figure 5These are SEM images of a single diamond on a plate, obtained by observing the diamond over time under the experimental conditions described above. The comparative example is a common octahedral diamond, which showed sharp edges before use, but after 10 and 15 hours, the edges were almost worn away. On the other hand, it can be seen that the edges of the boron-doped octahedral diamond in the examples showed less wear even after 10 and 26 hours of use.

[0094] refer to Figure 8 The weight change was confirmed by heat-treating the diamond at 750°C for 3 hours in air. In contrast to the 24.8% weight reduction of ordinary diamonds, the boron-doped diamond 300 (BDD) according to the invention showed a 2.5% weight reduction. For example, it is shown that the weight change rate of boron-doped diamonds is significantly lower than that of ordinary diamonds. That is, it can be confirmed that by suppressing the reaction of diamonds with oxygen in the air through boron doping, the chemical properties of diamonds are very stable.

[0095] Therefore, the diamond disc according to the present invention has the same properties as boron nitride (CBN) that does not react with iron (Fe), and can provide all the properties of a highly wear-resistant diamond, thereby improving the service life of the diamond disc.

[0096] In the following text, reference will be made to Figure 9 A method for manufacturing a diamond disc according to an embodiment of the present invention is described.

[0097] refer to Figure 9 A method for manufacturing a diamond disc according to an embodiment of the present invention may include a bonding material coating step S100, a pre-sintering step S200, a diamond supply step S300, and a heat treatment step S400.

[0098] In the bonding material coating step S100, the bonding material can be coated onto the surface of the shank base. The bonding material may include 60 wt% or more of Ni and other elements such as Cr and Si.

[0099] In the pre-sintering step S200, a solid-phase pre-sintered body can be formed through a pre-sintering process in which the bonding material coated onto the surface of the shank base is heated and dried to a first temperature range. This first temperature range can be between 600°C and 900°C. In the pre-sintering step S200, the ratio of the thickness of the final heat-treated bonding layer to the average diameter of the boron-doped diamond can be in the range of 30% to 65%.

[0100] In the diamond providing step S300, multiple boron-doped diamonds (BDDs) can be provided on the surface of the pre-sintered body. At this time, the multiple boron-doped diamonds can be temporarily attached to the pre-sintered body using a drilling jig and an adhesive.

[0101] In the heat treatment step S400, multiple boron-doped diamonds can be heat-treated within a second temperature range to set them as pre-sintered bodies exposed in an upright state. At least a portion of the multiple boron-doped diamonds can be self-standing with an angle C of greater than 60° and less than or equal to 90° relative to the shank base. In this case, the second temperature range can be from 1000°C to 1300°C.

[0102] In the heat treatment step S400, the solid pre-sintered body undergoes a phase transformation into a liquid bonding layer. Therefore, due to the buoyancy caused by the density difference, a portion (approximately 50 vol%) of the individual boron-doped diamonds can be exposed on top of the bonding layer 200, while the remaining portion (approximately 50 vol%) of the individual boron-doped diamonds can sink below the surface of the bonding layer.

[0103] At this point, boron-doped diamonds with their bottom vertex facing down are most stable. This may vary depending on the viscosity of the bonding layer at the high-temperature heat treatment temperature and the heat treatment time, but if maintained under these conditions for a long time, boron-doped diamonds may rotate and exhibit self-standing behavior.

[0104] In the heat treatment step S400, the wetting angle between the surface of the pre-sintered body and the surface of the boron-doped diamond can be maintained at greater than or equal to 0° and less than or equal to 60°. The smaller the wetting angle of the octahedral boron-doped diamond is to 60°, the better the chip groove can be formed. Since the boron-doped diamond is in point or line contact with the workpiece (polishing pad), the polishing performance of the boron-doped diamond on the workpiece can be significantly improved.

[0105] As described above, the boron-doped diamond with the octahedral structure of the present invention can achieve excellent wear resistance and high polishing performance. Since the self-standing ratio of boron-doped diamond exceeds a certain proportion, it has the advantage of improving wear resistance and polishing performance.

[0106] The examples of the present invention described above are specific embodiments, but these are merely examples, and the present invention is not limited thereto. Based on the technical concepts disclosed in this specification, it should be interpreted as having the broadest scope. Those skilled in the art can combine / replace the disclosed embodiments to achieve patterns of shapes not disclosed, which does not depart from the scope of the present invention. Furthermore, those skilled in the art can easily make changes or modifications to the disclosed embodiments based on this specification, and obviously, such changes or modifications all fall within the scope of the present invention.

Claims

1. A diamond disc, characterized in that, include: Handle base; A bonding layer is formed on the surface of the handle base; as well as Multiple boron-doped diamonds are exposed in the bonding layer. At least a portion of the plurality of boron-doped diamonds are disposed on the bonding layer in an arrangement intersecting the long axis of the boron-doped diamonds, with the uppermost face inclined downward from the upper end of the long axis. The wetting angle between the surface of the bonding layer and the surface of the boron-doped diamond is maintained at greater than or equal to 0° and less than or equal to 60°. The wetting angle is determined by the following formula 1: [Formula 1] F V = F D + F L cosθ Among them, F V It is an upward force, F D It is a downward force, F L It is the lateral force, and θ is the wetting angle.

2. The diamond disc according to claim 1, characterized in that, The long axis of the boron-doped diamond has an orientation of greater than 50° and less than or equal to 90° relative to the shank base, and the boron-doped diamond is disposed on the bonding layer.

3. The diamond disc according to claim 1, characterized in that, The ratio of the thickness of the bonding layer to the average diameter of the boron-doped diamond is in the range of 30% to 65%.

4. The diamond disc according to claim 1, characterized in that, The boron doping level in the boron-doped diamond is in the range of 1 ppm to 2000 ppm.

5. The diamond disc according to claim 1, characterized in that, The magnetic susceptibility per unit volume of the boron-doped diamond is in the range of 20 to 800 per unit volume.

6. The diamond disc according to claim 1, characterized in that, The ratio of the density of the boron-doped diamond to the density of the bonding layer is maintained in the range of 0.4 to 0.

6.

7. The diamond disc according to claim 4, characterized in that, The boron-doped diamond is an octahedral diamond. When the boron-doped diamond stands on the upper part of the bonding layer, the lower end of the boron-doped diamond makes point contact, line contact, or is spaced at a predetermined distance from the surface of the shank base.

8. The diamond disc according to claim 1, characterized in that, The pad polishing characteristics of the boron-doped diamond are such that, in a PCR testing device, when the CMP pad regulator made of the boron-doped diamond rotates at a speed of 100 rpm to 120 rpm and the polishing pad rotates at a speed of 80 rpm to 95 rpm, under the condition that the CMP pad regulator made of the boron-doped diamond applies a pressure of 4 to 9 lbf to the polishing pad, it takes more than 13 hours to reduce the PCR to 2 to 10 μm / hr for pad conditioning.

9. A method for manufacturing a diamond disc, characterized in that, Includes the following steps: In the combined material coating step, the bonding material is coated onto the surface of the handle base; In the pre-sintering step, the bonding material coated on the surface of the handle base is heated to a first temperature range to form a bonding layer in the form of a pre-sintered body. The diamond-providing step involves providing a plurality of boron-doped diamonds on the surface of the pre-sintered body; as well as The heat treatment step involves heat treatment within a second temperature range, such that at least a portion of the plurality of boron-doped diamonds are positioned on the bonding layer in an orientation that intersects with the long axis of the boron-doped diamonds, with the uppermost face inclined downwards from the upper end of the long axis. During the heat treatment step, the wetting angle between the surface of the bonding layer and the surface of the boron-doped diamond is maintained at greater than or equal to 0° and less than or equal to 60°. The wetting angle is determined by the following formula 1: [Formula 1] F V = F D + F L cosθ Among them, F V It is an upward force, F D It is a downward force, F L It is the lateral force, and θ is the wetting angle.

10. The method for manufacturing a diamond disc according to claim 9, characterized in that, During the heat treatment step, the long axis of the boron-doped diamond is exposed and placed in the bonding layer at an angle greater than 50° and less than or equal to 90° relative to the shank base.

11. The method for manufacturing a diamond disc according to claim 9, characterized in that, In the pre-sintering step, the first temperature range is 600°C to 900°C, and in the heat treatment step, the second temperature range is 1000°C to 1300°C.

12. The method for manufacturing a diamond disc according to claim 9, characterized in that, In the heat treatment step, the ratio of the thickness of the bonding layer to the average diameter of the boron-doped diamond after heat treatment is in the range of 30% to 65%.

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