CMP pad conditioner

Abstract

The present invention relates to a CMP pad conditioner having a substrate and a cutting tip pattern formed on at least one surface of the substrate, and more particularly to a CMP pad conditioner having cutting tip patterns, in which the cutting tip patterns have an improved structure that can increase the productivity of the CMP pad conditioner and that can sufficiently ensure the strength and safety of the cutting tip patterns.

Claims

1. A chemical mechanical polishing (CMP) pad conditioner, comprising: a substrate; and cutting tip patterns formed on at least one surface of the substrate, the cutting tip patterns comprised of: a plurality of substrate tip portions integrally formed on a surface of the substrate by mechanical processing, laser processing, or etching the surface of the substrate, the plurality of substrate tip portions spaced apart from each other, the plurality of substrate tip portions comprising first substrate tip portions; and diamond deposition tip portions each formed uniformly and directly only on each of top surfaces of the first substrate tip portions.

2. The CMP pad conditioner of claim 1, wherein the plurality of substrate tip portions include the substrate tip portions having different heights.

3. The chemical mechanical polishing (CMP) pad conditioner of claim 1, further comprising: second substrate tip portions on which the diamond deposition tip portions are not formed.

4. The CMP pad conditioner of claim 3, wherein the plurality of substrate tip portions are formed to have the same height; and the diamond deposition tip portions have the same thickness, are formed alternately on the substrate tip portions, whereby, when the diamond deposition tip portion is formed on one substrate tip portion, the diamond deposition tip portion is not formed on the substrate tip portions neighboring said one substrate tip portion on which the diamond deposition tip portion is formed.

5. The CMP pad conditioner of claim 3, wherein the substrate tip portions have a polygonal cross-sectional shape.

6. The CMP pad conditioner of claim 3, wherein the substrate tip portions have a polygonal, circular or elliptic planar shape.

7. The CMP pad conditioner of claim 3, wherein the diamond deposition tip portions have a thickness of 1 to 10 m.

8. The CMP pad conditioner of claim 7, wherein an upper surface of the cutting tip patterns is dressed with a wheel comprising an SiC abrasive material or a resin wheel comprising diamond grits so that a difference in height, a collapse of corners, and curved cross-sectional portions on the cutting patterns are eliminated.

9. The CMP pad conditioner of claim 3, wherein the CMP pad conditioner further comprises a diamond coating layer formed on both the substrate and the cutting tip patterns.

10. The CMP pad conditioner of claim 3, wherein the cutting tip patterns have a fine structure of 100 m or less.

11. The CMP pad conditioner of claim 1, wherein the substrate tip portions have a polygonal cross-sectional shape.

12. The CMP pad conditioner of claim 1, wherein the substrate tip portions have a polygonal, circular, or elliptic planar shape.

13. The CMP pad conditioner of claim 1, wherein the diamond deposition tip portions have a thickness of 1 to 10 m.

14. The CMP pad conditioner of claim 13, wherein an upper surface of the cutting tip patterns is dressed with a wheel comprising a SiC abrasive material or a resin wheel comprising diamond grits.

15. The CMP pad conditioner of claim 1, wherein the CMP pad conditioner further comprises a diamond coating layer formed on both the substrate and the cutting tip patterns.

16. The CMP pad conditioner of claim 1, wherein the cutting tip patterns have a fine structure of 100 m or less.

17. A chemical mechanical polishing (CMP) pad conditioner, comprising: a substrate of which a surface has a plurality of protrusions and a plurality of depressions formed by mechanical processing, laser processing, or etching the surface of the substrate, the plurality of protrusions comprising a first substrate tip portions spaced apart from each other; and diamond films each formed uniformly and directly only on each of top surfaces of the first substrate tip portions.

18. A chemical mechanical polishing (CMP) pad conditioner, consisting of: a substrate of which a surface has a plurality of protrusions and a plurality of depressions formed by mechanical processing, laser processing, or etching the surface of the substrate, the plurality of protrusions comprising a first plurality of substrate tip portions spaced apart from each other; and diamond films each formed uniformly and directly only on a top surface of the first plurality of substrate tip portions.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) FIG. 1 is a cross-sectional view of a conventional CMP pad conditioner.

(2) FIGS. 2a and 2b are cross-sectional views of a CMP pad conditioner according to one embodiment of the present invention.

(3) FIGS. 3a and 3b are cross-sectional views of a CMP pad conditioner according to another embodiment of the present invention.

(4) FIGS. 4a and 4b are cross-sectional views of a CMP pad conditioner according to still yet another embodiment of the present invention.

(5) FIGS. 5a and 5b are cross-sectional views of a CMP pad conditioner according to yet another embodiment of the present invention.

(6) FIG. 6 is a photograph showing a durability test for the cutting tip pattern of the CMP pad conditioner of FIG. 1.

(7) FIG. 7 is a photograph showing a durability test for the cutting tip pattern of a CMP pad conditioner according to the present invention.

DETAILED DESCRIPTION

(8) Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

(9) FIGS. 2a, 2b, 3a, and 3b are cross-sectional views of CMP pad conditioners wherein all the cutting tips of cutting patterns include substrate tip portions and deposition tip portions. FIGS. 4a, 4b, 5a, and 5b are cross-sectional views of CMP pad conditioners wherein only some of the cutting tips of cutting patterns include substrate tip portions and diamond deposition tip portions. As shown in these figures, a CMP pad conditioner 1, according to the present invention, includes a substrate 10 and cutting tip patterns 20 formed on at least one surface of the substrate 10.

(10) The substrate 10 may be made of a high-hardness material, such as a general iron alloy, a super-hard alloy, or a ceramic material, and may have a disc shape.

(11) Herein, the material of the substrate 10 is preferably at least one selected from among SiC, silicon nitride (Si.sub.3N.sub.4), tungsten carbide (WC), and mixtures thereof without limitation.

(12) In some cases, the substrate 10 may be made of one or more selected from among WC-based super-hard alloys, including tungsten carbide-cobalt (WCCo), tungsten carbide-titanium carbide-cobalt (WCTiCCo), and tungsten carbide-titanium carbide-tantalum carbide-cobalt (WCTiCTaCCo), as well as thermet (TiCN), boron carbide (B.sub.4C), and titanium borate (TiB.sub.2)-based super-hard alloys. In addition, the substrate may preferably be made of a ceramic material, such as silicon nitride (Si.sub.3N.sub.4), or silicon (Si). Other examples of the material of the substrate 10 include aluminum oxide (Al.sub.2O.sub.3), aluminum nitride (AlN), titanium oxide (TiO.sub.2), zirconium oxide (ZrOx), silicon oxide (SiO.sub.2), silicon carbide (SiC), silicon oxynitride (SiOxNy), tungsten nitride (WNx), tungsten oxide (WOx), diamond-like coating (DLC), boron nitride (BN), or chromium oxide (Cr.sub.2O.sub.3).

(13) Furthermore, in one embodiment the substrate has a disc shape when viewed from the top, and in some cases, may have a polygonal shape.

(14) In another embodiment, before the cutting tip patterns 20 are formed, at least one surface of the substrate 10 is planarized by grinding or lapping and is ultrasonically treated before deposition of the diamond deposition tip portions 23.

(15) The cutting tip patterns 20 include a plurality of substrate tip portions 21 formed on one surface of the substrate 10, and diamond deposition tip portions 23 formed on some or all of the plurality of substrate tip portions 21.

(16) The substrate tip portions 21 may be formed and spaced apart from each other on the substrate 10 with the same or different heights. As shown in FIGS. 2a through 4b, the substrate tip portions 21 may be portions having a rectangular cross-sectional shape, which are spaced apart from each other by depressions 25. Alternatively, as shown in FIGS. 5a and 5b, the substrate tip portions 21 may have a structure wherein the substrate tip portions 21, having a rectangular cross-sectional shape, and substrate tip portions 21a, having a triangular cross-sectional shape, are alternated with each other and spaced apart from each other by depressions 25. In addition, the substrate tip portions 21 may have a polygonal, circular, or oval shape when viewed from the top. Although not shown in the figures, it is be understood that the substrate tip portions 21 may have a polygonal horn shape, or a polygonal conical or elliptic conical shape, or a cylindrical or elliptic cylindrical shape, when viewed from the side and from the top.

(17) The substrate tip portions 21 may be formed by methods including mechanical processing, laser processing, or etching.

(18) Moreover, the diamond deposition tip portions 23 are formed on the plurality of substrate tip portions 21 to the same thickness. As shown in FIGS. 2a through 3b, the diamond deposition tip portions 23 may be formed on all of the substrate tip portions 21, or only on some of the plurality of substrate tip portions 21. In exemplary embodiments, as shown in FIGS. 4a through 5b, the diamond deposition tip portion 23 is formed on one substrate tip portion 21, of the adjacent substrate tip portions 21, and is not formed on the other substrate tip portion 21.

(19) As shown in FIGS. 5a and 5b, when the substrate tip portions 21 include substrate tip portions 21 having a rectangular cross-sectional shape, and substrate tip portions 21a having a triangular cross-sectional shape, both of which are alternated with each other, the diamond deposition tip portions 23 are formed on the substrate tip portions 21 having a rectangular cross-sectional shape.

(20) Herein, the diamond deposition tip portions 23 may be formed on the substrate tip portions 21 using chemical vapor deposition (CVD). For example, before the substrate tip portions 21 are formed, a diamond deposition layer may be formed on one surface of the substrate 10 and planarized, followed by partially removing the diamond deposition layer while leaving the diamond deposition layer in the regions wherein the substrate tip portions 21 are to be formed.

(21) Herein, chemical vapor deposition of the diamond deposition layer is performed under the following conditions: pressure: 10-55 Torr; flow rates of hydrogen and methane: 1-2 SLM, and about 25 SCCM, respectively; temperature of the substrate 10: about 900 C.; filament temperature: 1900-2000 C.; and distance between the substrate 10 and filaments: 10-15 mm.

(22) The diamond deposition layer thus deposited is planarized to a thickness of 1-10 m using a resin or ceramic polishing plate having 2000-mesh or larger particles in a planarization process in order to ensure the overall uniformity of the diamond deposition layer. Then, the diamond deposition tip portions 23 may be formed uniformly on the substrate tip portions 21 to a thickness of 1-10 m.

(23) Moreover, removal of the diamond deposition layer may be performed by etching (e.g., reactive ion etching, dry etching, wet etching, or plasma etching), mechanical processing, or laser processing.

(24) After the diamond deposition layer has been removed, the upper surface of the cutting patterns 20 is dressed by etching or mechanical processing in order to eliminate the difference in height, the collapse of the corners, or curved cross-sectional portions. This dressing process can be performed using a wheel having a SiC abrasive material, or a resin wheel having diamond grits. Herein, the abrasive wheel or the resin wheel having diamond grits includes fine abrasive particles having a size of 2,000 mesh or larger in view of surface toughness or the stability of the cutting tips.

(25) As shown in FIGS. 2a, 3a, 4a, and 5a, a diamond coating layer 30 may be formed on the substrate 10 and the cutting tip patterns 20, to a thickness thinner than that of the diamond deposition tip portions 23, using chemical vapor deposition. Before the diamond coating layer 30 is formed, the substrate 10 having the substrate tip portions 21 and the diamond deposition tip portions 23 formed thereon, is preferably subject to ultrasonic pretreatment. In this ultrasonic pretreatment process, fine scratches are formed on the deposition tip portions 23 and the remaining depressions 25 and substrate tip portions 21 using fine diamond particles in order to firm up the diamond coating layer. After the diamond coating layer 30 has been formed, the heights of the cutting tips of the cutting tip patterns 20 differ in an alternating pattern as shown in FIGS. 3a, 4a, and 5a.

(26) As shown in FIGS. 2b, 3b, 4b, and 5b, the diamond coating layer 30 can be omitted in some cases (e.g., where the durability of the cutting tip patterns 20 is sufficiently ensured by the substrate tip portions 21 and the diamond tip portions, or in consideration of the conditions of use).

(27) As described above, the CMP pad conditioner according to the present invention has a structure in which the diamond deposition tip portions 23 are formed on the substrate tip portions 21. Accordingly, the thickness of the diamond deposition tip portions 23 in the cutting tip patterns 20 may be very small, and thus the diamond that is deposited to form the diamond deposition tip portions 23 of the cutting tip patterns 20 may be deposited to a smaller thickness. Thus, even when the growth rate of diamond in the thermal filament process is as low as about 0.1-0.3 m/hr, the deposition time of diamond for forming the diamond deposition tip portions 23 is significantly reduced, because a significant portion of the height (30-60 m) of the cutting patterns 20 for use as the cutting tips of the conditioner 1 have the substrate tip portions 21. This can increase the productivity of the CMP pad conditioner 1.

(28) In addition, according to the present invention, the cutting tip patterns 20 are formed of the substrate tip portions 21 and the diamond deposition tip portions 23, which are formed on the substrate 10. Thus, the strength, stability, and durability of the cutting tip patterns 20 having a fine structure are sufficiently ensured, unlike the conventional CMP pad conditioner wherein the cutting tip pattern 120 is formed of only the diamond layer. Accordingly, the breakage and detachment of the cutting tip pattern 20 in a conditioning process can be prevented, so that the problem of scratching wafers is solved.

(29) The CMP pad conditioners according to the present invention, in particular the CMP pad conditioner 1 having the structure in which the cutting tip patterns 20 include cutting tips which are different in height, have the following excellent effects: pad polishing is performed by the higher cutting tip patterns 20; debris generated during the conditioning process is finely crushed by the lower cutting patterns; and sludge resulting from the polishing of wafers is efficiently discharged through the space provided by the difference in height between the cutting tip patterns 20.

(30) The durability of the cutting tip patterns 20 of the CMP pad conditioner 1 according to the present invention was tested, and the results of the test are shown in Table 1 below and FIGS. 6 and 7.

(31) In the durability test, sample 1 is a conventional CMP pad conditioner comprising cutting tip patterns formed of only diamond, and sample 2 is the inventive CMP pad conditioner wherein the cutting tip patterns, configured as shown in FIG. 2a, are composed of the substrate tip portions 21 and the diamond deposition tip portions 23.

(32) Herein, sample 1 was obtained by depositing diamond on a 20 mm super-hard substrate to a thickness of 35 m, forming cutting tip patterns (each 50 m (L)50 m (W)) at intervals of 1 mm using a laser, ultrasonically washing and pretreating the resulting structure, and forming a 5 m diamond coating layer on the patterns by a thermal filament process.

(33) Sample 2 was obtained by forming, on a 20 mm super-hard substrate 10, 35 m thick cutting tip patterns 20 composed of 5 m thick diamond deposition tip portions 23 and substrate tip portions 21, ultrasonically washing and pretreating the resulting structure, and forming a 5 m diamond coating layer on the resulting structure by a thermal filament process.

(34) TABLE-US-00001 TABLE 1 Shear height Shear Sample 1, measured Sample 2, measured (m) strength (g) at 5 points at 5 points 0 Average 44.3 864.9 20 Average 43.5 724.4 25 Average 39.3 663.7 30 Average 35.4 617.2

(35) As can be seen in Table 1 above, and FIGS. 6 and 7, sample 1 (i.e., the conventional CMP pad conditioner) exhibits an average shear strength of about 40 g, because it has low toughness against impact and load due to the inherent characteristics of diamond. In addition, as the shear height increases (i.e., goes toward the end of the cutting tip patterns), the shear strength decreases, suggesting that, as the height of the cutting tip patterns increases, the possibility of breakage or detachment at the end increases.

(36) Conversely, it can be seen that the shear strength of sample 2 (i.e., CMP pad conditioner 1 according to the present invention) is at least 10 times higher than that of sample 1 (viz., conventional) thanks to the mechanical toughness of the substrate tip portions 21.

(37) Thus, in the CMP pad conditioner 1 according to the present invention, the strength, stability, and durability of the cutting tip patterns 20 are sufficiently ensured.

(38) As described above, the productivity of the CMP pad conditioner according to the present invention is increased, because the cutting tip patterns are formed in a fast and easy manner. Also, the cutting tip patterns formed may have a fine structure while the strength and stability thereof can be sufficiently ensured.

(39) In addition, the CMP pad conditioner according to the present invention efficiently removes debris and expels foreign matter, such as sludge, during a conditioning process.

(40) Although the embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions, and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.