Grain type abrasive particles having basal part of tip

Abstract

This invention proposes a grinding particle with a pointed base, which improves physical properties and effectively performs precision processing, including conditioning and finishing, by extending the lifespan of the grinding particle, rapidly reaching a stable PCR value, and maintaining a stable PCR value for as long as possible. The grinding particle includes a cutting tip and a tip base. For grinding particles with a polyhedral and granular shape, the cutting tip protrudes from the tip base and is formed by removing a portion of the polyhedron, located inside the polyhedron.

Description

[Technical Field]

[0001] The present invention relates to abrasive particles, and more specifically, to abrasive particles having a particle morphology having a cutting tip protruding from the base of the tip, so as to facilitate the smooth and efficient performance of CMP conditioning, dressing and other similar tasks. [Previous Technology]

[0002] Abrasive particles are particles that smooth the surface of an object by friction or impact, and are widely used in various applications. For example, Chemical Mechanical Planarization (CMP) technology plans wafers by supplying slurry to an abrasive pad attached to a platen and by the relative motion between the platen and the carrier. However, during the abrasive process, due to the applied pressure and relative speed, the surface of the abrasive pad will deform unevenly over time, and the pores in the abrasive pad will be blocked by abrasive residue, causing the abrasive pad to malfunction. To solve the problems of uneven deformation and pore blockage of the abrasive pad, a CMP pad conditioner is used. The CMP pad conditioner corrects the deformation of the abrasive pad and forms new micropores by abrading the surface of the abrasive pad.

[0003] CMP pad conditioners utilize various methods, such as individual cutting tip methods (Korean Patent Nos. 10-1926449 and 10-2013383) and CVD diamond methods (Korean Patent No. 10-1178281, hereinafter referred to as CVD methods). However, the conventional individual cutting tip method using diamond particles, due to the polyhedral particle shape, leads to increased contact area with the grinding pad as the cutting tip wears down. After the cutting tip wears down, the pressure per unit area of ​​the grinding pad decreases, resulting in a sharp drop in the pad cutting rate (PCR). While attempts have been made to maintain the PCR value by appropriately adjusting the size of the grinding particles, this is not a fundamental solution. To address these issues, the CVD method was adopted, but its coating thickness also has a limited lifespan. Furthermore, for CVD conditioners with flat cutting tips, the time required to reach a stable PCR value during the pad breaking process in the initial stage of operation is relatively long.

[0004] On the other hand, not only in CMP pad conditioners, but also in precision grinding processes such as dressing, solutions are needed to extend the life of the grinding particles and maintain the grinding capacity for as long as possible in order to effectively perform precision processing such as conditioning and dressing. [Summary of the Invention]

[0005] Technical Problem to be Solved by the Invention: The problem to be solved by the present invention is to provide a grinding particle with a pointed base, which prolongs the lifespan of the grinding particle, quickly reaches a stable PCR value, and maintains a stable PCR value for as long as possible, thereby improving physical properties to effectively perform precision processing including conditioning and trimming. The technical solution of the present invention is as follows:

[0006] In order to solve the problem of the present invention, the abrasive particle with a tip base includes a cutting tip and a tip base. For abrasive particles in the form of a polyhedron and a particle, the cutting tip protrudes from the tip base. The cutting tip is formed by removing a portion of the polyhedron and is located inside the polyhedron.

[0007] In the abrasive particles of the present invention, the tip angle formed by the cutting tip and the tip base is smaller than the apex angle of the polyhedron. The average diameter of the cutting tip is less than half the diameter of the polyhedron. The inclination and concavity of the side surface of the cutting tip can be determined based on the grinding direction and support direction of the cutting tip. The cutting surface of the cutting tip may include a tip pattern having a linear, lattice, island, or combination thereof. The cross-section of the tip pattern may be angular, or form curvature, or a combination thereof. The periphery of the cutting tip may include protrusions projecting along the cutting surface direction of the cutting tip.

[0008] In the abrasive particles of the present invention, the aforementioned tip base is embedded by an adhesive layer. The height of the cutting tip exposed by the adhesive layer is less than the height of the cutting tip connected to the aforementioned tip base. Advantages compared to prior art

[0009] According to the present invention, the abrasive particles with a pointed base are used to extend the lifespan of the abrasive particles, quickly achieve a stable PCR value, and maintain a stable PCR value for as long as possible, thereby improving physical properties. With the improvement of the above physical properties, precision processing, including conditioning and trimming, can be performed effectively.

Implementation Method

[0019] Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings. The embodiments described below may take many different forms, and the scope of the invention is not limited to the embodiments described below. The embodiments of the present invention are intended to provide a more complete description for those skilled in the art. Exaggerated representations may have been used in the drawings for ease of explanation. Furthermore, terms indicating position such as upper, lower, and front are only relevant to the illustrations. In practice, the abrasive particles can be used in any selected direction, and the spatial orientation will vary depending on the direction and rotation of the abrasive particles during actual use.

[0020] Embodiments of the present invention provide a grinding particle that, by applying a grinding particle with a pointed base, extends the lifespan of the grinding particle, quickly reaches a stable PCR value, and maintains a stable PCR value for as long as possible, thereby improving physical properties and effectively performing precision processing, including conditioning and trimming. Therefore, a grinding particle with a pointed base will be discussed in detail, and the precision processing effect, including PCR value, will be explained in detail based on the above-described grinding particle. The grinding particle of the embodiments of the present invention is applicable to improving the effect of precision processing such as CMP pad conditioning and trimming. Here, a CMP pad conditioning example will be used for explanation.

[0021] Figure 1 is a diagram showing the first abrasive particle 100 in an embodiment of the present invention. However, this figure does not strictly represent all details, and for ease of explanation, there may be structural elements not shown in the figure.

[0022] According to FIG. 1, the first abrasive particle 100 includes a tip base 10 and a cutting tip 11. The cutting tip 11 is formed by removing a first region (Ra) of a polyhedron 13, and a cutting surface 12 is formed on its upper surface. To indicate the removed first region (Ra), the removed portion of the polyhedron 13 is indicated by a dashed line. The first abrasive particle 100 may contain alumina (Al₂O₃), silicon dioxide (SiO₂), silicon carbide (SiC), alumina-zirconia (Al₂O₃-ZrO₂), titanium diboride (TiB₂), boron carbide (B₄C), cubic boron nitride (CBN), diamond, etc. Preferably, superabrasive particles such as high-hardness diamond particles or CBN particles are used. These abrasive particles may be used alone or in a mixture of two or more particles.

[0023] Polyhedron 13 is a solid surrounded by multiple polygons. For illustrative purposes, polyhedron 13 is presented in a two-dimensional form in the figure, but polyhedra can have various shapes. Generally, CMP pad conditioners use diamond particles with a size of approximately 100-200 μm. The shapes of these diamond particles are mostly polyhedra, such as octahedrals and cube octahedrals. In recent years, to improve PCR, octahedral shapes are commonly used. The size of polyhedron 13 can vary depending on the application of the first abrasive particles 100, the arrangement of multiple first abrasive particles 100, etc. Compared to CVD types where the cutting tip is continuously present, polyhedron 13 exists independently and is referred to as particle morphology.

[0024] As grinding proceeds, the position and shape of the cutting surface 12 will change. When viewed vertically, the cutting surface 12 can be composed of polygons, circles, or a combination of polygons and circles. The shape of the cutting surface 12 may depend on the purpose of the first abrasive particles 100, the arrangement of the first abrasive particles 100, etc. The side surface (Sa) of the cutting tip 11 can have various shapes, which will be described in detail later. The side surface (Sa) of the cutting tip 11 may be composed of irregular surfaces that are unavoidably generated during the removal of the first region (Ra).

[0025] The cutting tip 11 is formed by removing the first region (Ra) of the polyhedron 13. Therefore, the cutting surface 12 and the side surface (Sa) of the cutting tip 11 form a tip angle (θ1). When the tip angle (θ1) is 0 degrees, the cutting surface 12 and the side surface (Sa) are at right angles. The closer the tip angle (θ1) is to 0 degrees, the better. In the polyhedron 13, the tip angle (θ1) is preferably less than 35 degrees for an octahedron. In other words, the tip angle (θ1) of the cutting tip 11 should be above 0 degrees and below 35 degrees, more preferably above 0 degrees and below 30 degrees. That is, the tip angle (θ1) is less than the apex angle of the polyhedron 13. If the side surface (Sa) is concave, a negative (-) tip angle (θ1) may occur.

[0026] The cutting tip 11 has a first width (Wa) as its average width, and the tip base 10 has a second width (Wb) as its maximum width. The second width (Wb) is the same as or smaller than the diameter of the polyhedron 13. The first width (Wa) should be less than half the diameter of the polyhedron 13, and the first width (Wa) can be less than 30 μm smaller than in conventional CVD methods. The first width (Wa) should be adjusted as much as possible to minimize breakage during use of the cutting tip 11. The first width (Wa) can be appropriately determined considering the purpose and arrangement of the first abrasive particles 100. The first width (Wa) being less than half the diameter of the polyhedron 13 and adjusted to a minimum to minimize breakage is based on the technical concept of maintaining the physical properties of the first abrasive particles 100 that distinguish the tip base 10. Therefore, the first width (Wa) should be determined considering the above-mentioned technical concept, rather than obtained through repeated experiments.

[0027] The tip base 10 is covered by the adhesive layer (BD), and an adhesive line (BL) is formed on the upper surface of the adhesive layer (BD). The adhesive line (BL) exists in the first region (Ra). Since the tip base 10 is buried in the adhesive layer (BD), the tip base 10 is firmly fixed relative to the polyhedron 13 by means of an anchoring effect, etc. Once the first abrasive particle 100 is firmly fixed, the risk of the first abrasive particle falling off during the abrasion process is almost eliminated. Although the tip base 10 may be completely buried in the adhesive layer (BD), if the height of the tip base is high enough relative to the size of the polyhedron, a portion of the tip base 10 may be exposed outside the adhesive layer (BD). Even if a portion of the tip base 10 is exposed outside the adhesive layer (BD), it can be applied smoothly as long as the risk of the first abrasive particle 100 falling off during the abrasion process is almost zero.

[0028] The cutting tip 11 has a first height (Ha), while the tip base 10 has a second height (Hb). The adhesive layer (BD) has a third height (Hc), and the cutting tip 11 exposed by the adhesive layer (BD) has a fourth height (Hd). Since the tip base 10 is buried by the adhesive layer (BD), the first height (Ha) is greater than the fourth height (Hd). The fourth height (Hd) can be maximized by adjusting the cutting tip 11 to minimize breakage during use and the required grinding work. The fourth height (Hd) can be appropriately determined based on the purpose, arrangement, etc., of the first abrasive particles 100.

[0029] FIG2 is a diagram showing a modified example of the first abrasive particle of the present invention. In this case, the modified example shows a variety of shapes of the cutting tip 11. Regarding the first abrasive particle 100, please refer to FIG1.

[0030] According to Figure 2, the modified examples 100a, 100b, 100c, and 100d of the first abrasive particle respectively include different first to fourth cutting tips 11a, 11b, 11c, and 11d. The two sides (Sb, Sc) of the first cutting tip 11a have the same inclination (θ1), while the two sides (Sb, Sc) of the second cutting tip 11b have different inclinations (θ1, θ2). The two sides (Sb, Sc) of the third cutting tip 11c are concave, while one side (Sb) of the fourth cutting tip 11d is concave. In the first to fourth cutting tips 11a, 11b, 11c, and 11d, one side (Sb) of the two sides (Sb, Sc) is the grinding direction during grinding, while the other side (Sc) is the support direction that supports the pressure applied by the first to fourth cutting tips 11a, 11b, 11c, and 11d during the grinding process. That is, the aforementioned inclination and concavity are determined based on the grinding direction and the support direction.

[0031] FIG3 is a diagram showing the second abrasive particle 200 according to an embodiment of the present invention. Here, the second abrasive particle 200 has a different arrangement direction than the first abrasive particle 100.

[0032] According to FIG. 3, the second abrasive particle 200 includes a tip base 20 and a cutting tip 21. The cutting tip 21 is formed by removing a second region (Rb) of a polyhedron 23, and a cutting surface 22 is formed on its upper surface. To indicate the removed second region (Rb), the removed portion of the polyhedron 23 is indicated by a dashed line. The second abrasive particle 200 is the same as the first abrasive particle 100 except for the shape of the tip base 20 and the cutting tip 21. Specifically, the first and second widths (Wa, Wb) and the first to fourth heights (Ha, Hb, Hc, Hd) are consistent with those described in the first abrasive particle 100. In particular, since the tip base 20 is covered by an adhesive layer (BD), the first height (Ha) is greater than the fourth height (Hd). The cutting surface 22 of the second abrasive particle 200 may also have an inclined surface depending on the configuration direction.

[0033] FIG4 is a cross-sectional view showing a third abrasive particle 300 according to an embodiment of the present invention. Here, the third abrasive particle 300 is described with reference to the first abrasive particle 100, but the same applies to the second abrasive particle 200.

[0034] According to FIG. 4, the third abrasive particle 300 includes a tip base 30 and a cutting tip 31. The cutting tip 31 is formed by removing a third region (Rc) of a polyhedron 33, and a cutting surface 32 is formed on its upper surface. To indicate the removed third region (Rc), the removed portion of the polyhedron 33 is represented by a dashed line. The third abrasive particle 300 is the same as the first abrasive particle 100 except for the shape of the tip base 30 and the cutting tip 31. Specifically, the first and second widths (Wa, Wb) and the first to fourth heights (Ha, Hb, Hc, Hd) are consistent with those described in the first abrasive particle 100. In particular, since the tip base 30 is covered by an adhesive layer (BD), the first height (Ha) is greater than the fourth height (Hd).

[0035] The cutting tip 31 is surrounded by a protrusion 34 projecting toward the cutting surface 32. The protrusion 34 has a fifth height (He) and includes a concave groove 35. The protrusion 34 is covered by an adhesive layer (BD). The protrusion 34 and the groove 35 are covered by the adhesive layer (BD) and are more firmly fixed than the first and second abrasive particles 100, 200 due to anchoring effects, etc. The protrusion 34 may form one or more circular bands or extend spirally from the cutting tip 31. The protrusion 34 may be continuous or discontinuous. In this case, a portion of the protrusion 34 may be exposed outside the adhesive layer (BD).

[0036] FIG5 is a cross-sectional view of the fourth abrasive particle 400 according to an embodiment of the present invention, and FIG6 is a diagram showing that the cutting surface 12 of the fourth abrasive particle 400 in FIG5 is square when viewed from a vertical angle. The first abrasive particle 100 is used as an example for description here, but it can also be applied to the second and third abrasive particles 200 and 300.

[0037] According to Figures 5 and 6, the cutting surface 12 of the fourth abrasive particle 400 is provided with a pointed pattern 40. The pointed pattern 40 divides the cutting surface 12 to make the part actually participating in the grinding sharp. The pointed pattern 40 can be arranged in the form of lines a, 40a, grid b, 40b, island c, 40c, etc. Here, we take the wedge-shaped cross section 41 of the pointed pattern 40 as an example, but it can also be formed by any shape among polygons and curved surfaces. In other words, the cross section 41 of the pointed pattern 40 is angular, or forms curvature or a combination thereof. The pointed patterns 40 can be arranged regularly at certain intervals, or irregularly without intervals.

[0038] Figures 7 and 8 are photographs showing the first and third abrasive particles 100 and 300 according to an embodiment of the present invention. Although the second abrasive particle 200 is not mentioned here, the same applies to it. The first and third abrasive particles 100 and 300 are formed by laser removal of the first and third regions (Ra, Rc). The laser source is a Pico sec UV laser (15 ps), with a power of 7W to 16W and a frequency of 100 to 300 kHz.

[0039] According to Figures 7 and 8, the first abrasive particle 100, as shown in Figure 1, includes a tip base 10 and a cutting tip 11. The tip base 10 and the cutting tip 11 are formed by removing a first region (Ra). As shown in Figure 7, the first abrasive particles (a, b) having the shape of the tip base 10 and the cutting tip 11 vary depending on the power, frequency, and processing speed of the laser source. The third abrasive particle 300, as shown in Figure 4, includes a tip base 30, a cutting tip 31, and a protrusion 34. The tip base 30, the cutting tip 31, and the protrusion 34 are formed by removing a third region (Rc). As shown in Figure 8, the third abrasive particles (a, b) having the shape of the tip base 30, the cutting tip 31, and the protrusion 34 vary depending on the power, frequency, and processing speed of the laser source.

[0040] The first to third abrasive particles 100, 200, and 300 are suitable for CMP pad conditioners, etc., and are manufactured by attaching a polyhedron to a shank, laser-processing the polyhedron to form the first to third abrasive particles 100, 200, and 300, and forming an adhesive layer (BD). Here, the adhesive layer (BD) can be achieved by electroplating, melting, coating with organic materials, etc. Here, for the purpose of explaining the first to third abrasive particles 100, 200, and 300 in detail, the adhesive layer (BD) is not described.

[0041] Figure 9 is a conceptual comparison of the grinding methods of the grinding particles (a) of the embodiment of the present invention, conventional grinding particles (b), and conventional CVD (c). Figure 10 is a graph showing the grinding time and PCR (Pad Cutting Rate) of the grinding particles (a, b, c) of Figure 9. Here, the grinding particles (a) of the embodiment of the present invention are described using the first grinding particle (100) as an example, but the same applies to the second and third grinding particles 200 and 300.

[0042] According to FIG. 9, the abrasive particles (a) of the present invention, as described above, are formed by removing the first to third regions (Ra, Rb, Rc) of polyhedra 13, 23, and 33. The conventional abrasive particles (b) are the same as the polyhedra 13, 23, and 33 mentioned in the first to third abrasive particles 100, 200, and 300. The conventional CVD (c) is coated on the protrusion (P20), and there is a CVD layer (P21) that actually participates in the abrasion. Depending on the abrasion direction (GD), the positions of the cutting surfaces 12, 22, and 32 of the abrasive particles (a), the cutting surface (P10) of the abrasive particles (b), and the cutting surface (P22) of the abrasive particles (c) will be different. For ease of explanation, it is assumed that the initial positions of the cutting surfaces 12, 22, and 32 of the abrasive particles (a), the cutting surface (P10) of the abrasive particles (b), and the cutting surface (P22) of the abrasive particles (c) are the same.

[0043] Before the abrasive particle (b) reaches the critical point of increased contact area (P11), the contact area increases rapidly, making grinding difficult. After the abrasive particle (c) wears down, the bottom substrate (P20) is exposed, reaching the cutting limit point (P23), making further grinding impossible. However, even if the abrasive particle (a) reaches the positions of the comparative critical point of increased contact area (P11) and cutting limit point (P23), grinding can still continue. Here, the positions of the critical point of increased contact area (P11) and cutting limit point (P23) may vary depending on the shape of the abrasive particles (b, c). Specifically, the example in the figure is an example where the critical point of increased contact area (P11) is reached later than the cutting limit point (P23), but the critical point of increased contact area (P11) is reached earlier than the cutting limit point (P23).

[0044] According to Figure 10, the pad cutting rate (PCR) of the abrasive particles (a, b, c) differs over the grinding time (t). In the initial grinding stage, abrasive particles (a) and (b) exhibit almost identical behavior, while abrasive particle (c) may have a lower initial PCR due to its flat cutting surface (P22). The grinding hold time (ta) of abrasive particle (a) is relatively longer than that of abrasive particle (b) (tb) and abrasive particle (c) (tc). Compared to abrasive particle (b), the cutting tips 11, 21, and 31 of abrasive particle (a) show less particle size variation, and compared to abrasive particle (c), the fourth height (hd) involved in grinding is larger. Therefore, the grinding hold time (ta) of abrasive particle (a) is maintained for a longer period compared to abrasive particles (b, c). Meanwhile, abrasive particle (b) has a relatively shorter grinding time (tb) due to the limitation of the CVD layer (P21) thickness.

[0045] The first to third abrasive particles 100, 200, and 300 of the embodiments of the present invention are characterized in that the contact area can be adjusted by artificial processing such as laser processing, and therefore are not limited by the size of diamond particles typically used in CMP pad conditioners, i.e., 100~200μm.

[0046] The present invention has been described in detail above, but the present invention is not limited to the above embodiments. Within the scope of the technical concept of the present invention, those skilled in the art can make various modifications. [Simplified Explanation of the Diagram]

[0010] Figure 1 is a diagram showing the first abrasive particle of the present invention.

[0011] Figure 2 is a diagram showing a modified example of the first abrasive particle of the present invention.

[0012] Figure 3 is a diagram showing the second abrasive particle of the present invention.

[0013] Figure 4 is a cross-sectional view showing the third abrasive particle of the present invention.

[0014] Figure 5 is a cross-sectional view showing the fourth abrasive particle of the present invention.

[0015] Figure 6 is a diagram showing the cutting surface of the fourth abrasive particle in Figure 5.

[0016] Figures 7 and 8 are photographs showing the first and third abrasive particles of the present invention.

[0017] Figure 9 is a conceptual comparison of the grinding methods using the grinding particles of the present invention (a), conventional grinding particles (b), and conventional CVD (c).

[0018] Figure 10 is a graph showing the grinding time of the grinding particles (a, b, c) in Figure 9 and the PCR.

Claims

1. An abrasive particle with a pointed base, comprising a cutting tip and a pointed base, the abrasive particle being polyhedral and granular, characterized in that the cutting tip protrudes from the pointed base, the cutting tip is formed by removing a portion of the polyhedron, the cutting tip being located inside the polyhedron.

2. The abrasive particle with a pointed base as described in claim 1, characterized in that the tip angle formed by the cutting tip and the tip base is smaller than the apex angle of the polyhedron.

3. The abrasive particle with a pointed base as described in claim 1, characterized in that the average diameter of the cutting tip is less than 1 / 2 of the diameter of the polyhedron.

4. The abrasive particle with a pointed base as claimed in claim 1, characterized in that the inclination and concavity of the side of the cutting tip are determined based on the grinding direction of the cutting tip and the support direction of the cutting tip.

5. The abrasive particle with a pointed base as claimed in claim 1, characterized in that the cutting surface of the cutting tip includes a tip pattern having a linear, lattice, island, or combination thereof shape.

6. The abrasive particle with a pointed base as claimed in claim 5, characterized in that the cross-section of the pointed pattern is angular, or forms curvature, or a combination thereof.

7. The abrasive particle with a pointed base as claimed in claim 1, characterized in that the periphery of the cutting tip includes a protrusion projecting along the cutting surface direction of the cutting tip.

8. The abrasive particle with a pointed base as claimed in claim 1, characterized in that the pointed base is embedded in an adhesive layer.

9. The abrasive particle with a pointed base as claimed in claim 8, characterized in that the height of the cutting tip exposed by the adhesive layer is less than the height of the cutting tip connected to the base of the tip.

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