Diamond disc and its manufacturing method

Abstract

The diamond disk includes a shank base, a bonding layer formed on the surface of the shank base, and a plurality of boron-doped diamonds arranged so as to be exposed to the bonding layer, and at least a portion of the plurality of boron-doped diamonds can be arranged on the bonding layer in such a manner that a face arranged at the uppermost end meets the long axis of the boron-doped diamond and is inclined downward from the upper end of the long axis.

Description

[Technical Field]

[0001] The present invention relates to a diamond disk and a method for manufacturing the same. [Background technology]

[0002] Generally, the CMP (Chemical Mechanical Polishing) process is a chemical-mechanical polishing process that simultaneously utilizes polishing removal and the dissolving action of chemical solutions to obtain flatness of semiconductor wafers.

[0003] The principle of CMP polishing is to supply a slurry containing abrasive particles and chemicals onto the polishing pad while the polishing pad and wafer are pressed against each other and moved relative to each other. At this time, the numerous foam pores on the surface of the polishing pad, made of polyurethane material, serve to retain new abrasive, achieving consistent polishing efficiency and uniform polishing across the entire wafer surface.

[0004] However, due to the pressure and relative velocity applied during polishing, the surface of the polishing pad deforms unevenly over the course of processing time, and the pores on the polishing pad become clogged with polishing residue, preventing the polishing pad from fulfilling its function. As a result, it becomes impossible to achieve global planarization over the entire wafer surface or uniform polishing between wafers during the entire processing time.

[0005] To solve the problem of uneven deformation of the CMP polishing pad and clogging of the pores, a CMP pad conditioning operation is carried out by finely polishing the surface of the polishing pad using a CMP pad conditioner, so that new micropores are formed.

[0006] To increase productivity, the CMP pad conditioning process can be performed simultaneously with the main CMP process, known as in-situ conditioning.

[0007] The polishing solution used in CMP contains abrasive particles such as silica, alumina, and ceria, and the CMP process is broadly divided into oxide CMP and metal CMP depending on the type of polishing solution used. The polishing solution for oxide CMP used in the former has a pH value of mainly 10-12, while the polishing solution for metal CMP used in the latter has a pH of 4 or less and is an acidic solution.

[0008] Conventional CMP pad conditioners are generally classified into two types: electrodeposited CMP pad conditioners, which are manufactured by electrodeposition, and fused CMP pad conditioners, which are manufactured by melting metal powder at high temperatures. These CMP pad conditioners mainly use granular diamond particles as the abrasive. The diamond particles are fixed in a metal matrix formed by electrodeposition or fusion.

[0009] Diamond is known to be the hardest substance on earth, and due to this property, diamond tools made from artificial diamonds are produced and used.

[0010] In the conventional CMP process, diamonds are used in the CMP pad conditioner together with slurry for wafer polishing. When highly corrosive slurry is used, additives in the slurry react with the carbon in the diamond, accelerating diamond wear and shortening the life of the diamond disk. [Prior art documents] [Patent documents]

[0011] [Patent Document 1] Korean Patent Publication No. 10-2012-0058303 Summary of the Invention [Problem to be solved by the invention]

[0012] An object of the present invention is to provide a diamond disk having improved wear resistance and high grinding performance, and a method for manufacturing the same. [Means for solving the problem]

[0013] According to one aspect of the present invention, a diamond disk can be provided which includes a shank base; a bonding layer formed on the surface of the shank base; and a plurality of boron-doped diamonds (BDDs) arranged so as to be exposed to the bonding layer, wherein at least some of the plurality of boron-doped diamonds are arranged on the bonding layer with the surface arranged at the uppermost end thereof meeting the long axis of the boron-doped diamonds and inclining downward from the upper end of the long axis.

[0014] The boron-doped diamond may be disposed on the bonding layer such that the major axis of the boron-doped diamond has an orientation of more than 50° and not more than 90° relative to the shank base.

[0015] In addition, the wetting angle at which the surface of the bonding layer meets the surface of the boron-doped diamond may be maintained at 0° or more and 60° or less.

[0016] The ratio of the thickness of the bonding layer to the average diameter of the boron-doped diamond may be in the range of 30% to 65%.

[0017] The amount of boron doped into the boron-doped diamond may be in the range of 1 ppm to 2000 ppm.

[0018] Furthermore, the magnetic susceptibility per unit volume of the boron-doped diamond can be in the range of 20 to 800 per unit volume.

[0019] Also, 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.

[0020] In addition, the boron-doped diamond is an octahedron diamond, and the lower end of the boron-doped diamond can be in point or line contact with the surface of the shank base or can be spaced a predetermined distance apart when the boron-doped diamond is erected on top of the bonding layer.

[0021] In addition, the pad polishing characteristics (PCR: Pad cut rate) of the boron-doped diamond can be measured in a PCR test device by rotating the CMP pad conditioner made of the boron-doped diamond at 100 rpm to 120 rpm and the polishing pad at 80 rpm to 95 rpm. When the CMP pad conditioner made of the boron-doped diamond presses the polishing pad at a pressure of 4.5 to 9 lbf, it can take 13 hours or more for the PCR to decrease to a range of 2 to 10 μm / hr due to pad conditioning.

[0022] According to another aspect of the present invention, a method for manufacturing a diamond disk can be provided, including a bonding material application step of applying a bonding material to the surface of a shank base; a pre-sintering step of heating the bonding material applied to the surface of the shank base in a first temperature range to form a bonding layer in the form of a pre-sintered body; a diamond providing step of providing a plurality of boron-doped diamonds (BDDs) on the surface of the pre-sintered body; and a heat treatment step of heat-treating at least some of the plurality of boron-doped diamonds in a second temperature range so that the surface located at the uppermost end of the boron-doped diamonds is arranged in the bonding layer in an orientation that meets the long axis of the boron-doped diamonds and is inclined downward from the upper end of the long axis.

[0023] In the heat treatment step, the boron-doped diamond may be positioned so that its major axis is exposed to the bonding layer at an angle of more than 50° and not more than 90° relative to the shank base.

[0024] In addition, the first temperature range in the preliminary sintering step may be 600°C to 900°C, and the second temperature range in the heat treatment step may be 1000°C to 1300°C.

[0025] In addition, during the heat treatment, a wetting angle between the surface of the bonding layer and the surface of the boron-doped diamond may be maintained in the range of 0° to 60°.

[0026] In addition, in the heat treatment step, the thickness ratio of the bonding layer after the heat treatment to the average diameter of the boron-doped diamond may be in the range of 30% to 65%. [Effects of the Invention]

[0027] According to the embodiment of the present invention, there is an advantage that excellent wear resistance and high grinding performance can be realized by using boron doped diamond (BDD) with an octahedral structure.

[0028] Furthermore, according to an embodiment of the present invention, the diamond is an octahedral boron doped diamond (BDD), and the proportion of the boron doped diamond that is self-standing is greater than a certain ratio, which has the advantage of improving wear resistance and enhancing grinding performance. [Brief explanation of the drawings]

[0029] [Figure 1] FIG. 1 is a diagram showing a state in which boron-doped diamond (BDD) is temporarily attached onto a bonding layer in the form of a pre-sintered body in a diamond disk according to one embodiment of the present invention. [Figure 2] FIG. 2 is a diagram showing a state in which boron-doped diamond (BDD) stands up on the bonding layer after heat treatment in a diamond disk according to one embodiment of the present invention. [Figure 3] FIG. 3 is a diagram showing a state in which boron-doped diamond (BDD) is wetting onto the bonding layer after heat treatment in a diamond disk according to one embodiment of the present invention. [Figure 4] FIG. 4 is a photograph comparing the wear state of a diamond disc according to an embodiment of the present invention with that of a general diamond. [Figure 5] FIG. 5 is a photograph comparing the wear state of a diamond disc according to an embodiment of the present invention with that of a general diamond. [Figure 6] FIG. 6 is a magnified photograph comparing a diamond disk to which boron-doped diamond (BDD) according to one embodiment of the present invention is applied and a diamond disk to which a general octahedral diamond not doped with boron is applied. [Figure 7] FIG. 7 is a graph showing PCR tests of diamond disks to which boron-doped diamond (BDD) and general octahedral diamond are applied according to one embodiment of the present invention. [Figure 8] FIG. 8 is a graph showing the weight loss rate due to heat treatment in boron-doped diamond (BDD) according to one embodiment of the present invention and regular diamond. [Figure 9] FIG. 9 is a block diagram illustrating a method for manufacturing a diamond disk according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0030] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific embodiments for realizing the technical concept of the present invention will be described in detail with reference to the accompanying drawings.

[0031] In the description of the present invention, if it is determined that a specific description of related publicly known configurations or functions may obscure the gist of the present invention, the detailed description will be omitted.

[0032] Furthermore, when a component is referred to as being "coupled," "supported," "connected," "supplied," "transmitted," or "contacted" to another component, it should be understood that the component may be directly coupled, supported, connected, supplied, transmitted, or contacted to the other component, but that other components may also be present in between.

[0033] The terms used in this specification are merely used to describe specific embodiments and are not intended to limit the present invention. The singular expressions include the plural expressions unless the context clearly indicates otherwise.

[0034] It should be noted that the expressions "upper side," "lower side," "side," etc. in this specification are explained based on the illustrations in the drawings, and it should be made clear in advance that they may be expressed differently if the orientation of the object changes. For the same reason, some components in the accompanying drawings are exaggerated, omitted, or shown schematically, and the size of each component does not completely reflect the actual size.

[0035] Furthermore, terms including ordinal numbers such as first, second, etc. may be used to describe various components, but the corresponding components are not limited by such terms. These terms are used only to distinguish one component from another.

[0036] As used herein, the meaning of "comprising" is to embody certain properties, regions, constants, steps, operations, elements and / or components, and does not exclude the presence or addition of other certain properties, regions, constants, steps, operations, elements, components and / or groups.

[0037] First, when comparing the chemical components of diamond between regular diamond and boron-doped diamond (BDD) according to the present invention, in highly corrosive environments (e.g., W CMP, Oxide CMP processes), the wear resistance of boron-doped diamond (BDD) is superior to that of regular diamond, but in less corrosive general environments, there is no significant difference between the wear resistance of regular diamond and that of boron-doped diamond (BDD).

[0038] The electrodeposition CMP diamond disc manufacturing method uses a nickel electroplating bonding layer to support the non-conductive diamond. However, boron-doped diamond (BDD), which conducts electricity, cannot be used in the electrodeposition process using conventional methods because the nickel electroplating layer covers the surface of the boron-doped diamond during electroplating. Therefore, boron-doped diamond (BDD) can be used to manufacture diamond discs using the fusion and sintering methods.

[0039] Additionally, when machining typical iron-based metals, diamond has an affinity for iron-based metals, making metal machining difficult. When slurry is supplied to the polishing pad during CMP pad conditioning, the iron (Fe) component in the slurry reacts with the carbon in the diamond on the diamond disk, accelerating the wear of the diamond. This ultimately accelerates the wear of the diamond and shortens its lifespan. However, the boron-doped diamond (BDD) of the present invention acts as a blocking layer to inhibit the oxidation reaction of carbon (C + O2 → CO2), thereby improving the stability of the diamond disk.

[0040] The differences in manufacturing between the boron-doped diamond (BDD) according to the present invention, ordinary diamond, and conventional boron nitride (CBN: cubic boron nitride) are shown in Table 1 below.

[0041] [Table 1] In the case of the boron-doped diamond according to the present invention, Fe, Ni alloy and boron (Boron: pure boron or boron carbide) are catalysts, and boron can substitute for carbon during diamond synthesis or can penetrate into the diamond structure. This boron-doped diamond can suppress the reaction between external iron (Fe) and carbon in the diamond, and can provide all the characteristics of abrasion-resistant diamond.

[0042] On the other hand, in the case of ordinary diamonds, Fe and Ni alloys are used as a catalyst for carbon, but they do not contain boron. Boron nitride (CBN: cubic boron nitride) has a relatively large amount of boron added, so that the carbon to boron ratio is 1:1, so it does not react with iron (Fe). However, it has much lower strength than boron-doped diamonds and it can be difficult to adjust the shape.

[0043] In this embodiment, among the diamonds used in the diamond disk, boron-doped diamond (BDD) can be used at 5 vol% or more of the entire diamond depending on the application.The octahedral structure ratio in the boron-doped diamond (BDD) can be 50% or more.Of the entire boron-doped diamond (BDD), the ratio of self-standing boron-doped diamond (BDD) in the bonding layer can be 60% or more.

[0044] The ratio can be determined by observing the entire diamond in a certain area and determining the percentage of diamonds that meet the above criteria.

[0045] Hereinafter, a specific configuration of a diamond disk according to an embodiment of the present invention will be described with reference to FIGS.

[0046] 1 to 6, a diamond disk according to the present invention can be used in a CMP pad conditioner to finely polish the surface of a polishing pad. The diamond disk can include a shank base 100, a bonding layer 200, and a plurality of boron-doped diamonds (BDD) 300.

[0047] Specifically, the shank base 100 is a backing plate for a disk, and a bonding layer 200 can be formed on the surface of the shank base 100. The shank base 100 corresponds to a typical shank base 100 used as a backing plate for a disk, and therefore a detailed description thereof will be omitted.

[0048] The bonding layer 200 may be made of a bonding material containing 60 wt% or more of Ni and other elements such as Cr and Si. The bonding material may be applied to the surface of the shank base 100, and then dried and pre-sintered to form a solid-phase pre-sintered body. An adhesive for temporarily bonding the boron-doped diamond 300 may be applied to the upper surface of the pre-sintered body. The boron-doped diamond 300 may be temporarily bonded to the upper surface of the pre-sintered body to which the adhesive has been applied using a drilling jig.

[0049] The pre-sintered body can be formed as a bonding layer 200 through a heat treatment process together with the boron-doped diamond 300. The bonding layer 200 can be transformed into a liquid state through a high-temperature heat treatment process, and the boron-doped diamond 300 can be disposed in an upright state on the bonding layer 200. The bonding layer 200 with the boron-doped diamond 300 disposed in an upright state can be cooled and dried.

[0050] The density of the bonding layer 200 is 6 g / cm 3 ~8.3g / cm 3 The density of boron-doped diamond 300 can be in the range of 3.5 g / cm 3 ~3.6g / cm 3 In this embodiment, the density of the bonding layer 200 can be in the range of 7.6 g / cm 3 and the density of boron-doped diamond 300 is 3.54 g / cm 3 is.

[0051] The ratio of the density of the 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 of the density of the boron-doped diamond 300 to the density of the bonding layer 200 is higher than 0.6, the buoyancy of the boron-doped diamond 300 due to the density difference between the bonding layer 200 and the boron-doped diamond 300 is too low, so the boron-doped diamond 300 may be immersed inside the bonding layer 200. If the ratio of the density of the boron-doped diamond 300 to the density of the bonding layer 200 is lower than 0.4, the buoyancy of the boron-doped diamond 300 due to the density difference between the bonding layer 200 and the boron-doped diamond 300 is too large, so the boron-doped diamond 300 may float on the upper surface of the bonding layer 200 and tilt horizontally.

[0052] The boron-doped diamond 300 may be formed by incorporating Fe, Ni alloy and boron (Boron: pure boron or boron carbide) as a catalyst in carbon. For example, the boron-doped diamond 300 may include Fe, Ni alloy and 1 ppm to 2000 ppm of boron (Boron: pure boron or boron carbide) in carbon. In the diamond structure, boron may substitute for carbon or may be inserted into the diamond structure. This boron-doped diamond 300 can provide high wear resistance without reacting with external iron (Fe).

[0053] The boron-doped diamond 300 may have a TI (Toughness Index) of 20 to 50 and a TTI (Temperature Toughness Index) of 14 to 45. The boron-doped diamond 300 may have a magnetic susceptibility per unit volume MS (Magnetic Susceptibility) of 20 to 800, more preferably 30 to 500.

[0054] Fe, Ni, and other metals used as catalysts in the synthesis of boron-doped diamond 300 are contained within the diamond as foreign matter. Generally, the amount of foreign matter increases proportionally with the amount of boron doping. If the MS value is less than 20, the amount of boron doping is too low, potentially reducing the effectiveness of boron in improving corrosion resistance. If the MS value exceeds 800, the amount of boron doping is high, but excessive contamination with ferromagnetic metal foreign matter such as Fe and Ni can degrade the physical properties of the diamond and cause problems such as cracking of diamond particles during CMP pad conditioning. The greater the amount of metal foreign matter within boron-doped diamond 300, the lower the TI and TTI values, which can also be determined through MS measurements. Diamond toughness (TI, TTI, or MS) must be high enough to withstand prolonged use under pressure under CMP conditions.

[0055] The boron-doped diamond 300 can be an octahedron diamond. Diamond can be manufactured in an octahedron shape depending on the synthesis conditions, and the octahedron diamond has sharp edges, and in the octahedron diamond, the angle between the line connecting the vertex and the center and the face is 35° to 45°.

[0056] Such boron doped diamond (BDD) 300 can be provided in a plurality of pieces arranged so as to be exposed to the bonding layer 200. At least some of the plurality of boron doped diamonds 300 can be arranged on the bonding layer 200 with the long axis L at an angle C of more than 50° and not more than 90° relative to the shank base 100.

[0057] In this embodiment, the imaginary line connecting the two vertices of the diamond 300 that are opposite each other and farthest apart can be defined as an "axis," and the longest axis among these multiple "axes" can be defined as the "major axis (L)." Furthermore, a "vertex" can be defined as the point where adjacent corners meet, and if the adjacent corners do not meet as a "point" (for example, if the part corresponding to the vertex is rounded), the imaginary point where the extended corners meet when the adjacent corners are extended can be defined as the vertex. A boron-doped diamond with a major axis of 50° or more can be defined as self-standing.

[0058] Furthermore, the boron-doped diamond 300 being self-standing can be understood to mean that the boron-doped diamond 300 is arranged independently on the bonding layer 200 with the long axis L of the boron-doped diamond 300 at an angle C of more than 50° and less than 90° relative to the shank base 100. When the boron-doped diamond 300 is self-standing on the bonding layer 200, the apex of the lower end of the long axis direction of the boron-doped diamond 300 may be in point or line contact with the surface of the shank base 100 or may be spaced a predetermined distance apart.

[0059] When the long axis L of the boron-doped diamond 300 is 35° relative to the shank base 100, the boron-doped diamond 300 comes into surface contact with the workpiece (polishing pad), which may significantly reduce the polishing performance of the boron-doped diamond 300 against the workpiece.As the long axis L of the boron-doped diamond 300 approaches 90° relative to the shank base 100, the boron-doped diamond 300 comes into point contact with the workpiece (polishing pad), which can significantly improve the polishing performance of the boron-doped diamond 300 against the workpiece.

[0060] In order for the long axis L of the boron-doped diamond 300 to be positioned in the bonding layer 200 at an angle C greater than 50° and less than 90° relative to the shank base 100, the wetting angle θ where the surface of the boron-doped diamond 300 meets the surface of the bonding layer 200 must be less than 90°, and preferably the components of the bonding layer 200 must be configured to be less than 60°.

[0061] Referring to FIG. 3 and the following formula 1, the wetting angle θ is determined by the upward force F V and the downward force F D and the horizontal force F L The force can be determined by the vertical component of the force.

[0062] [Formula 1] F V =F D +F L cosθ When the wetting angle θ exceeds 90°, F L Since the vertical component of the force is upward, the boron-doped diamond 300 can float further. When the wetting angle θ is less than 90°, the force F L Since the direction of the vertical component of the force can be changed to a downward side direction, the boron-doped diamond 300 can receive a downward force.

[0063] For example, if the wetting angle θ is greater than 90°, the bonding layer 200 will not be able to properly support the boron-doped diamond 300 due to its buoyancy, increasing the risk of the boron-doped diamond 300 falling off, and chip pockets for discharging debris generated during polishing will not be formed in the bonding layer 200, preventing proper discharge of the debris and significantly reducing polishing performance. Preferably, for the octahedral boron-doped diamond 300, the wetting angle θ is less than 60°, allowing the boron-doped diamond 300 to make point or line contact with the workpiece (polishing pad), effectively forming chip pockets and significantly improving the polishing performance of the boron-doped diamond 300 on the workpiece.

[0064] 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 200 is too thick, the exposed height of the boron-doped diamond 300 in the bonding layer 200 will be low, and the boron-doped diamond 300 will float due to buoyancy, allowing the boron-doped diamond 300 to come into surface contact with the workpiece. Also, if a chip pocket for discharging residues generated during polishing with the boron-doped diamond 300 is formed shallowly in the bonding layer 200, the residues generated during polishing may not be discharged smoothly.

[0065] If the wetting angle of the boron-doped diamond (BDD) 300 is less than 60°, the boron-doped diamond 300 will be driven deeper into the bonding layer 200 due to surface tension, which may reduce the height at which the boron-doped diamond 300 protrudes from the bonding layer 200. Therefore, the thickness of the bonding layer 200 must be strictly controlled to ensure a discharge path for residues generated during polishing of the diamond disk.

[0066] Furthermore, if the bonding layer 200 is thinner than the appropriate thickness, self-standing may occur due to buoyancy (difference in density between the boron-doped diamond and the bonding layer) and wetting. In this case, the chip pocket is successfully formed in the bonding layer 200, but if the bonding layer 200 is too thin, the boron-doped diamond 300 comes into contact with the shank base 100, and the boron-doped diamond 300 is subjected to further downward force due to surface tension. At this time, the boron-doped diamond 300 tilts and becomes horizontal, so the exposed height of the boron-doped diamond 300 in the bonding layer 200 decreases, and the boron-doped diamond 300 may come into surface contact with the workpiece. For example, if the diamond is placed on its side in the bonding layer 200 in an orientation where the angle between the long axis of the boron-doped diamond 300 and the shank base 100 is an angle C of approximately 35° to 45°, the self-standing ratio of the boron-doped diamond 300 may be low.

[0067] The thickness of the bonding layer 200 according to the present invention has a certain ratio to the average diamond grain 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 present invention can be in the range of 30% to 65%. [Table 2] is a table showing the diamond ratio (self-standing ratio) and PCR (Pad cut rate) for each height of the bonding layer 200. The diamond grain size has a certain range depending on the mesh size, and the average size of the diamond complies with 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. 400 diamonds / cm on a disk with a diameter of approximately 4 inches. 2 The diamonds are deposited at a density of 1000. The number of diamonds deposited per unit area can vary depending on the average size of the diamonds.

[0068] [Table 2] Referring to Table 2, when the bonding layer thickness is 68 μm, 79 μm, and 94 μm, the diamond exposure height is relatively high compared to the bonding layer thickness, the diamond ratio with a good angle (e.g., the self-standing ratio) is the highest, and the PCR is also the highest. When the bonding layer thickness is 106 μm, the diamond exposure height is also relatively low compared to the bonding layer thickness, the diamond ratio with a good angle (self-standing ratio) is low, and the PCR is also low. When the bonding layer thickness is 52 μm, the diamond exposure height is relatively high compared to the bonding layer thickness, but the diamond ratio with a good angle (self-standing ratio) is slightly lower, and the PCR also decreases slightly.

[0069] That is, if the thickness ratio of the bonding layer 200 to the average diameter of the boron-doped diamond 300 is 70% or more, the PCR becomes very low, so the thickness ratio of the bonding layer 200 to the average diameter of the boron-doped diamond 300 must be controlled to less than 70%. And if the thickness of the bonding layer 200 is too thin, even if the PCR value is maintained to a certain extent, there is a risk of the diamond falling off, so the thickness of the bonding layer 200 must be at least 30% or more of the average size of the diamond. Therefore, the thickness ratio of the bonding layer 200 to the average diameter of the boron-doped diamond 300 is preferably in the range of 30% to 65%.

[0070] Figure 6 shows cross-sectional photographs of boron-doped octahedral diamond 300 and regular octahedral diamond after heat treatment. Even though regular diamonds that are not doped with boron have an octahedron shape, when a PCR test is carried out for 15 minutes in a PCR test device, the PCR value of the regular diamond is lower than that of boron-doped diamond (BDD) 300 under the same conditions. Blocky type diamonds, i.e., cube-octahedral shaped diamonds, whether boron-doped or not, show very low PCR values ​​in PCR tests under the same conditions as boron-doped diamond disks.

[0071] Referring to Figure 7, to measure the long-term PCR (Pad Cut Rate) of disks fabricated from boron-doped diamond 300 and general octahedral diamond, a PCR test device, polishing pad, CMP pad conditioner, and slurry are prepared. As an example, a CTS CMP polisher can be used as the PCR test device, a 20" diameter IC1010 (Dupont) product can be used as the polishing pad, and a W7000 (Cabot Microelectronics) product can be used as the slurry. The CMP pad conditioner can be equipped with a 4" diameter boron-doped octahedral diamond 300 and a general octahedral diamond.

[0072] After preparing the PCR test equipment, polishing pad, CMP pad conditioner, and slurry, the polishing pad was rotated at 80-95 rpm and the CMP pad conditioner was rotated at 100-120 rpm. The time required for the CMP pad conditioner's boron-doped diamond 300 or general octahedral diamond to pressurize the polishing pad at 4-9 lbf was measured until the PCR fell below the minimum PCR value for pad conditioning. If the PCR value fell below the set value, the CMP pad conditioner was deemed inadequate. The CMP pad conditioner was then capable of polishing the polishing pad by moving back and forth from the center to the edge of the polishing pad 18-20 times per minute, delivering 300 ml of slurry to the polishing pad per minute.

[0073] Long-term PCR tests confirmed that a CMP pad conditioner equipped with a general octahedral diamond required 8 hours to reach a PCR of 10 μm / hr, while a CMP pad conditioner equipped with boron-doped diamond 300 required 13 hours to reach a PCR of 10 μm / hr. In the PCR tests described herein, the CMP pad conditioner required 13 hours to reach a PCR of 10 μm / hr, but a time longer than 13 hours is also within the scope of the present invention. The longer the time required for a CMP pad conditioner to reach a PCR of 10 μm / hr, the more advantageous it is. Therefore, there is no need to specify an upper limit for the time required for a CMP pad conditioner to reach a PCR of 10 μm / hr. However, the time required for a CMP pad conditioner to reach a PCR of 10 μm / hr may be 100 hours. Furthermore, even when the set value was, for example, 5 μm / hr or 2 μm / hr, it was confirmed that boron-doped diamond 300 maintained its pad polishing characteristics for 30% or more longer than ordinary octahedral diamond.

[0074] Figures 4 and 5 are SEM photographs of individual diamonds on a disk over time under the above experimental conditions. The comparative example is a regular octahedral diamond. Sharp edges are observed before use, but after 10 and 15 hours, the edges are observed to have worn away. On the other hand, the boron-doped octahedral diamond used in the example shows relatively little edge wear even after 10 and 26 hours of use.

[0075] Referring to Figure 8, the weight change can be confirmed by treating only diamond in an air atmosphere at 750°C for 3 hours. While the weight of ordinary diamonds decreased by 24.8%, the weight of the boron-doped diamond (BDD) 300 according to the present invention decreased by 2.5%. For example, the boron-doped diamond showed a significantly lower weight change rate than ordinary diamonds. This confirms that boron doping prevents diamonds from reacting with oxygen in the air, making them highly chemically stable.

[0076] Therefore, the diamond disc according to the present invention can provide all the wear-resistant characteristics of diamond while retaining the same characteristics as boron nitride (CBN) that does not react with iron (Fe), thereby improving the lifespan of the diamond disc.

[0077] Hereinafter, a method for manufacturing a diamond disk according to one embodiment of the present invention will be described with reference to FIG.

[0078] Referring to FIG. 9, a method for manufacturing a diamond disk according to an embodiment of the present invention may include a bonding material applying step S100, a pre-sintering step S200, a diamond providing step S300, and a heat treatment step S400.

[0079] In the bonding material application step S100, a bonding material may be applied to the surface of the shank base. The bonding material may contain 60 wt% or more of Ni and other elements such as Cr and Si.

[0080] In the pre-sintering step S200, the bonding material applied to the surface of the shank base is heated and dried in a first temperature range to form a solid-phase pre-sintered body. At this time, the first temperature range may be a temperature range of 600°C to 900°C. In the pre-sintering step S200, the thickness ratio of the bonding layer after the final heat treatment to the average diameter of the boron-doped diamond may be in the range of 30% to 65%.

[0081] In the diamond providing step S300, a plurality of boron doped diamonds (BDDs) can be provided on the surface of the pre-sintered body, and the boron doped diamonds can be temporarily bonded onto the pre-sintered body with an adhesive using a drilling jig.

[0082] In the heat treatment step S400, the plurality of boron-doped diamonds may be heat-treated in a second temperature range so that they are arranged in an upright state and exposed to the pre-sintered body. At least some of the plurality of boron-doped diamonds may be self-standing with their major axes L at an angle C of more than 60° and not more than 90° relative to the shank base. In this case, the second temperature range may be a temperature range of 1000°C to 1300°C.

[0083] In the heat treatment step S400, the solid-phase pre-sintered body changes into a liquid bonding layer, so that a portion (about 50 vol%) of each boron-doped diamond can be exposed to the upper surface of the bonding layer 200 due to buoyancy caused by density difference, and the remaining portion (about 50 vol%) of each boron-doped diamond can sink below the surface of the bonding layer.

[0084] At this time, it is most stable for the octahedral boron-doped diamond to have its bottom apex pointing downward. This may vary depending on the viscosity of the bonding layer and the heat treatment time at high heat treatment temperature, but if maintained under these conditions for a long period of time, the boron-doped diamond may rotate, resulting in a self-standing phenomenon.

[0085] 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 between 0° and 60°. The smaller the wetting angle of the octahedral boron-doped diamond is, the better the chip pocket formation, and the boron-doped diamond makes point or line contact with the workpiece (polishing pad), which significantly improves the polishing performance of the boron-doped diamond on the workpiece.

[0086] As described above, the present invention can realize excellent wear resistance and high grinding performance through the octahedral boron-doped diamond, and has the excellent advantage that the rate at which the boron-doped diamond is self-standing is above a certain ratio, thereby improving wear resistance and grinding performance.

[0087] Although the embodiments of the present invention have been described above using specific examples, these are merely examples, and the present invention is not limited thereto and should be construed as having the broadest scope in accordance with the technical ideas disclosed herein. Those skilled in the art may combine / substitute the disclosed examples to implement patterns of shapes not shown, but this would not depart from the scope of the present invention. Furthermore, those skilled in the art may easily modify or change the disclosed examples based on this specification, and it is clear that such modifications or changes also fall within the scope of the present invention.

Claims

1. 1. A diamond disc for use in a chemical mechanical polishing pad conditioner, comprising: Shank base; a bonding layer formed on the surface of the shank base; and a plurality of boron-doped diamonds (BDDs) arranged so as to be exposed to the bonding layer; At least some of the boron-doped diamonds are arranged on the bonding layer in such a manner that the uppermost surfaces intersecting with the long axes of the boron-doped diamonds are inclined downward from the upper ends of the long axes; The boron-doped diamond is placed on the bonding layer in an orientation such that the long axis of the boron-doped diamond forms an angle of more than 50° and not more than 90° with respect to the shank base; a wetting angle between the surface of the bonding layer and each surface of the boron-doped diamond is maintained between 0° and 60°; The wetting angle is determined by the following equation: [Formula 1] F V =F D +F L ・cosθ wherein, at the contact point between the surface of the bonding layer and the surface of the boron-doped diamond, F V is an upward force acting due to the interfacial energy between the boron-doped diamond and air, F D is a downward force acting due to the interfacial energy between the boron-doped diamond and the bonding layer, F L is a force acting on the contact point of the bonding layer due to the interfacial energy between the bonding layer and air, and θ is a wetting angle, diamond disk.

2. 2. The diamond disk according to claim 1, wherein 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%.

3. 2. The diamond disk according to claim 1, wherein the amount of boron doped into the boron-doped diamond is in the range of 1 ppm to 2000 ppm.

4. 2. The diamond disk according to claim 1, wherein the magnetic susceptibility per unit volume of the boron-doped diamond is in the range of 20 to 800 per unit volume.

5. 2. A diamond disk according to claim 1, wherein 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.

6. The boron-doped diamond is an octahedron diamond, The diamond disk of claim 3, wherein the lower end of the boron-doped diamond makes point or line contact with the surface of the shank base or is spaced a predetermined distance from the surface when the boron-doped diamond is raised on top of the bonding layer.

7. The pad polishing characteristics (PCR: Pad cut rate) of the boron-doped diamond are measured in a PCR test device, where the CMP pad conditioner made of the boron-doped diamond rotates at 100 rpm to 120 rpm and the polishing pad rotates at 80 rpm to 95 rpm, and the CMP pad conditioner made of the boron-doped diamond presses the polishing pad at a pressure of 4 to 9 lbf, and it takes 13 hours or more for the PCR to decrease to a range of 2 to 10 μm / hr due to pad conditioning.

8. A method for manufacturing a diamond disc, comprising: The diamond disc is used in a chemical mechanical polishing pad conditioner; The manufacturing method includes: a bonding material application step of applying a bonding material to a surface of the shank base; a pre-sintering step of heating the bonding material applied to the surface of the shank base within a first temperature range to form a bonding layer in the form of a pre-sintered body; a diamond providing step of providing a plurality of boron-doped diamonds (BDDs) on the surface of the pre-sintered body; and a heat treatment step of performing a heat treatment in a second temperature range, wherein at least some of the boron-doped diamonds are placed on the bonding layer with their uppermost surfaces intersecting with the long axes of the boron-doped diamonds tilted downward from the upper ends of the long axes; and In the heat treatment step, the boron-doped diamond is placed on the bonding layer in an exposed state in an orientation such that the long axis of the boron-doped diamond has an angle of more than 50° and not more than 90° with respect to the shank base; In the heat treatment step, a wetting angle between a surface of the bonding layer and each surface of the boron-doped diamond is maintained between 0° and 60°, The wetting angle is determined by the following equation: [Formula 1] F V =F D +F L ・cosθ wherein, at the contact point between the surface of the bonding layer and the surface of the boron-doped diamond, F V is an upward force acting due to interfacial energy between the boron-doped diamond and air, F D is a downward force acting due to the interfacial energy between the boron-doped diamond and the bonding layer, F L is a force acting on the contact point of the bonding layer due to the interfacial energy between the bonding layer and air, and θ is a wetting angle.

9. 9. The method for manufacturing a diamond disk according to claim 8, wherein the first temperature range in the preliminary sintering step is 600°C to 900°C, and the second temperature range in the heat treatment step is 1000°C to 1300°C.

10. 9. The method for manufacturing a diamond disk according to claim 8, wherein in the heat treatment step, the thickness ratio of the bonding layer after the heat treatment to the average diameter of the boron-doped diamond is in the range of 30% to 65%.

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