EDGE POLISHING DRUM FOR WAFERS AND EDGE POLISHING EQUIPMENT FOR WAFERS INCLUDING THE SAME

CROSS-REFERENCE TO RELATED PATENT APPLICATIONS

[0001]This application claims the benefit of Korean Patent Application No. 10-2024-0087750, filed on Jul. 3, 2024, which is hereby incorporated by reference as if fully set forth herein.

BACKGROUND OF THE INVENTION

Field of the Invention

[0002]The present disclosure relates to an edge polishing drum for wafers and edge polishing equipment for wafers including the same, and more particularly to an edge polishing drum for wafers, which is configured to polish an edge front bevel and an edge back bevel in an edge area of a wafer, and edge polishing equipment for wafers including the same.

Discussion of the Related Art

[0003]A silicon wafer may be manufactured through a single crystal growth process for production of an ingot, a slicing process for slicing the ingot, thereby obtaining a wafer having a thin disc shape, an edge grinding process for machining a circumferential portion of the wafer obtained through the slicing process in order to prevent fracture or distortion of the wafer, a lapping process for removing damage, caused by mechanical machining, remaining in the wafer, a polishing process for mirror-polishing the wafer, and a cleaning process for removing an abrasive and foreign matter attached to the polished wafer.

[0004]After the above-mentioned edge grinding process, an edge polishing process for mirror-polishing a rough surface of an edge area of the wafer is performed.

[0005]Generally, the edge area of the wafer is polished using a device referred to as an “edge polishing drum”. Wafers subjected to an edge grinding process may have slightly-different edge shapes, that is, shape variability. Even when edge polishing is performed for wafers using an edge polishing drum having a uniform shape, shapes of edge areas of the polished wafers may have variability.

SUMMARY OF THE INVENTION

[0006]Accordingly, the present disclosure is directed to an edge polishing drum for wafers and edge polishing equipment for wafers including the same that substantially obviate one or more problems due to limitations and disadvantages of the related art.

[0007]An object of the present disclosure is to provide an edge polishing drum for wafers, which is configured to uniformly polish an edge area of a wafer, and edge polishing equipment for wafers including the same.

[0008]Objects of the present disclosure are not limited to the above-described objects, and other objects of the present disclosure not yet described will be more clearly understood by those skilled in the art from the following detailed description.

[0009]To achieve these objects and other advantages and in accordance with the purpose of the disclosure, as embodied and broadly described herein, an edge polishing drum for wafers includes a body part having a disc shape, and a polishing part extending inclinedly from an edge of the body part toward a first face of the body part, wherein the polishing part includes an inner surface surrounding a polishing area adjacent to the first face of the body part, wherein the inner surface of the polishing part includes a first surface extending from the first face of the body part and a second surface configured to contact an edge area of a wafer to be polished, wherein the second surface includes a first area having a 2-1th angle with respect to the first face of the body part, and a second area having a 2-2th angle with respect to the first face of the body part, and wherein the first area is disposed between the first face of the body part and the second area.

[0010]The first area and the second area may have an equal width, and may surround the polishing area.

[0011]The first area and the second area may be continuously disposed while surrounding the polishing area.

[0012]The 2-2th angle may be greater than the 2-1th angle.

[0013]The 2-1th angle may be 11°, and the 2-2th angle may be 30°.

[0014]The first surface may have a first angle with respect to the first face of the body part, and the first angle may be greater than the 2-1th angle and the 2-2th angle.

[0015]The edge polishing drum may have a first rotation axis, and the first rotation axis may be tilted with respect to a direction perpendicular to the first face of the body part.

[0016]A tilting angle of the first rotation axis may be 2°.

[0017]The edge polishing drum may further include polishing pads respectively provided in the first area and the second area of the second surface of the polishing part.

[0018]In another aspect of the present disclosure, edge polishing equipment for wafers includes the above-described edge polishing drum for wafers, and a wafer support chuck disposed to be spaced apart from the first face of the body part of the edge polishing drum while facing the first surface.

[0019]A first rotation axis of the edge polishing drum may be tilted from a second rotation axis of the wafer support chuck.

[0020]The second rotation axis may be inclined by a predetermined angle with respect to a direction perpendicular to the first face of the body part.

[0021]In the wafer edge polishing drum according to the above-described embodiment of the present disclosure and the wafer edge polishing equipment including the same, the edge front bevel and the edge back level of the wafer may be uniformly polished by virtue of the inner surface of the polishing part, in particular, the first area and the second area having different angles at the second surface of the inner surface, and tilting of a first rotation axis, about which the polishing part rotates, with respect to a second rotation axis, about which the wafer rotates. Accordingly, it may be possible to control variability of a polishing amount and, as such, to reduce shape variability of the wafer after completion of polishing.

BRIEF DESCRIPTION OF THE DRAWINGS

[0022]The accompanying drawings, which are included to provide a further understanding of the disclosure and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the disclosure and along with the description serve to explain the principle of the disclosure. In the drawings:

[0023]FIG. 1 is a view showing edge polishing equipment for wafers according to an embodiment of the present disclosure;

[0024]FIG. 2 is a view concretely showing an edge polishing drum for wafers shown in FIG. 1;

[0025]FIG. 3 is a view concretely showing a first surface, a second surface, and a third surface shown in FIG. 2;

[0026]FIG. 4 is a plan view of an inner surface of a polishing part of the wafer edge polishing drum;

[0027]FIG. 5 is a view showing a polishing action of a wafer by the inner surface of the polishing part of the wafer edge polishing drum of FIG. 4;

[0028]FIGS. 6 and 7 show results of measurement of profiles of wafers according to TABLE 1 using an EZ300; and

[0029]FIG. 8 is a diagram showing the entire configuration of the edge polishing equipment for wafers.

DETAILED DESCRIPTION OF THE INVENTION

[0030]Hereinafter, the present disclosure will be described with reference to embodiments, for concrete description thereof, and the embodiments will be described in detail with reference to the accompanying drawings, for better understanding of the present disclosure.

[0031]However, the embodiments of the present disclosure may be modified to various different forms, and the scope of the present disclosure should not be interpreted as being limited to embodiments described below. The embodiments of the present disclosure are provided to more fully describe the present disclosure to those having ordinary skill in the art.

[0032]In addition, although relational terms such as “first”, “second”, “upper”, “lower”, etc. may be construed only to distinguish one element from another element without necessarily requiring or involving a certain physical or logical relation or sequence between the elements.

[0033]In an edge polishing drum for wafers according to the present disclosure and edge polishing equipment for wafers including the same, an inner surface of a polishing part configured to polish an edge area of a wafer, in particular, a second surface of the inner surface performing a polishing action while directly friction-contacting the edge area of the wafer is constituted by a first area and a second area respectively having different angles and a rotation axis of the edge polishing drum is tilted with respect to the wafer such that the entirety of the edge area of the wafer is uniformly polished during edge-polishing of the wafer to control variability of a polishing amount and, as such, a wafer with an edge having a uniform shape may be manufactured after the edge-polishing.

[0034]FIG. 1 is a view showing edge polishing equipment for wafers according to an embodiment of the present disclosure. FIG. 2 is a view concretely showing an edge polishing drum for wafers shown in FIG. 1. FIG. 3 is a view concretely showing a first surface, a second surface, and a third surface shown in FIG. 2.

[0035]The edge polishing equipment for wafers according to the embodiment of the present disclosure may include a wafer edge polishing drum 1000, and a wafer support chuck 2000 disposed to be spaced apart from a first face 1012 of a body part 1010 of the wafer edge polishing drum 1000 while facing the first face 1012.

[0036]The wafer edge polishing drum 1000 configured to polish a wafer and the wafer support chuck 2000 configured to support a wafer may rotate independently. As shown in FIG. 1, the wafer edge polishing drum 1000 and the wafer support chuck 2000 may rotate in the same direction or in different directions, respectively. In this case, a rotation axis of the wafer edge polishing drum 1000, that is, a first axis, and a rotation axis of the wafer support chuck 2000, that is, a second axis, may be tilted from each other. For example, the first axis and the second axis may be tilted from each other by 2°, as shown in FIG. 1.

[0037]In addition, the second axis is tilted by a predetermined angle with respect to a direction perpendicular to the first face 1012 of the body part 1010 of the wafer edge polishing drum 1000. In FIG. 1, the predetermined angle may be 2°, as described above.

[0038]The wafer support chuck 2000 includes a rotation body 2220 and a support body 2210. The rotation body 2220 is a part rotating about the second axis, and the support body 2210 is a part supporting a wafer while rotating in accordance with rotation of the rotation body 2220.

[0039]Meanwhile, the polishing drum 1000 is provided with a polishing part 1050 at the body part 1010 thereof. The polishing part 1050 has an inner surface facing a wafer to be polished. The inner surface includes a first surface 1052, a second surface 1054, and a third surface 1056. Detailed configurations of the polishing drum 1000 will be described later with reference to FIGS. 2 and 3.

[0040]The second surface 1054 includes a first area 1054a and a second area 1054b. The first area 1054a is disposed between the first surface 1052 of the body part 1010 and the second area 1054b. That is, referring to FIGS. 1 to 3, the second area 1054b is disposed under the first area 1054a.

[0041]In addition, polishing pads 1060a and 1060b configured to polish a wafer while friction-contacting the wafer may be provided at the first area 1054a and the second area 1054b, respectively. When an edge of a wafer is polished, mechanical polishing by friction-contact of the wafer edge with the polishing pads and chemical polishing using polishing slurry may be simultaneously performed.

[0042]As shown in FIG. 2, the wafer edge polishing drum according to the embodiment of the present disclosure may include the body part 1010, which has a disc shape while having a predetermined thickness, and the polishing part 1050.

[0043]The body part 1010 may include the first face 1012 facing a wafer which is an object to be polished, and the second face 1014 opposite to the first face 1012. The first axis, about which the wafer edge polishing drum and the body part 1010 rotate, may be perpendicular to at least one of the first face 1012 or the second face 1014 of the body part 1010.

[0044]The polishing part 1050 may extend inclinedly from an edge of the body part 1010 toward the first face 1012 of the body part 1010. Assuming that a space in which a wafer is polished is defined as a “polishing area”, the polishing area may be provided adjacent to the first face 1012 of the body part 1010, and the inner surface of the polishing part 1050 may be disposed to surround the polishing area.

[0045]The inner surface of the polishing part 1050 may include the first surface 1052, the second surface 1054 (FIG. 1), and the third surface 1056, and the second surface 1054 may include the first area 1054a and the second area 1054b. The first surface 1052 may extend from the first face 1012 of the body part 1010. The first area 1054a of the second surface 1054 may extend from the first surface 1052, and the second area 1054b of the second surface 1054 may extend from the first area 1054a. The first area 1054a and the second area 1054b are portions to contact an edge area of the wafer to be polished. The third surface 1056 may extend from the second area 1054b of the second surface 1054, and may be disposed outside the edge area of the wafer.

[0046]In FIG. 2, each of the first surface 1052, the first and second areas 1054a and 1054b of the second surface 1054, and the third surface 1056 may be provided at left and right sides with reference to the first axis in a symmetrical manner.

[0047]Referring to FIG. 3, the first surface 1052 may have a first angle θ1 with respect to the first face 1012 of the body part 1010, and the third surface 1056 may have a third angle θ3 with respect to the first face 1012 of the body part 1010.

[0048]In addition, the first area 1054a and the second area 1054b of the second surface 1054 may form a 2-1th angle θ21 and a 2-2th angle θ22 with respect to the first face 1012 of the body part 1010, respectively. The 2-1th angle θ21 and the 2-2th angle θ22 may be different from each other. In detail, the 2-2th angle θ22 may be greater than the 2-1th angle θ21. For example, the 2-1th angle θ21 may be 11°, and the 2-2th angle θ22 may be 30°.

[0049]In addition, the first angle θ1 may be greater than the 2-1th angle θ21 and the 2-2th angle θ22, and the 2-1th angle θ21 and the 2-2th angle θ22 may be greater than the third angle θ3. That is, when the inner surface of the polishing part 1050 extends from the first face 1012 of the body part 1010, the first surface 1052 of the inner surface may extend while forming a greatest angle with respect to the first face 1012, and the third surface 1056 of the inner surface may extend while forming a smallest angle with respect to the first face 1012.

[0050]FIG. 4 is a plan view of the inner surface of the polishing part of the wafer edge polishing drum.

[0051]As shown in FIG. 4, the inner surface of the polishing part 1050 may include the first surface 1052, the second surface 1054 (FIG. 1) including the first area 1054a and the second area 1054b, and the third surface 1056, and the polishing pads 1060a and 1060b may be provided in the first area 1054a and the second area 1054b, respectively. In particular, the polishing pads 1060a and 1060b may be provided to be adjacent to each other. One polishing pad 1060a may be provided in plural such that the plurality of polishing pads 1060a is spaced apart from one another, and the other polishing pad 1060b may be provided in plural such that the plurality of polishing pads 1060b is spaced apart from one another.

[0052]In FIG. 4, the first area 1054a and the second area 1054b may have an equal width, and may be provided to extend continuously without being spaced apart from each other.

[0053]FIG. 5 is a view showing a polishing action of a wafer by the inner surface of the polishing part of the wafer edge polishing drum of FIG. 4.

[0054]In FIG. 5, a process for polishing an edge front bevel which is an upper portion of the wafer edge area is shown, and polishing performed by the first area 1054a and the second area 1054b of the second surface included in the above-described inner surface of the polishing part is shown. A portion of the edge front bevel polished by the first area 1054a of the second surface is indicated by “A”, and a portion of the edge front bevel polished by the second area 1054b of the second surface is indicated by “B”.

[0055]Since the first axis and the second axis are tilted from each other, and the second surface includes the first area and the second area respectively having different angles, as described above, the edge front bevel of the wafer may be polished at the portions A and B thereof. In particular, since the second surface of the inner surface of the polishing part forms angles of, for example, 11° and 30°, with respect to the first face of the body part, various portions of the edge front bevel of the wafer may be polished.

[0056]TABLE 1 shows results of polishing of edge areas of wafers by respective edge polishing drums according to a comparative example and first and second examples.

[0057]The second example is the case in which the 2-1th angle and the 2-2th angle as described above are 11° and 30°, respectively, the first example is the case in which the 2-1th angle and the 2-2th angle are 18° and 30°, and the comparative example is the case in which both the 2-1th angle and the 2-2th angle are 30°.

[0058]In addition, “FZDD148” and “FZDD149” represent numerical values measured in portions of a front edge area spaced apart from a center of a wafer by 148 mm and 149 mm, respectively, when the diameter of the wafer is 300 mm. When such a numerical value is reduced, flatness of the corresponding portion of the edge area of the wafer may be enhanced and, as such, an enhancement in roundness may be achieved.

[0059]When the edge of the wafer is polished multiple times, for example, at high and low speeds, each numerical value in TABLE 1 may be ranged within a certain range. In this case, the numerical value shown in TABLE 1 represents an average value.

[0060]When the edge area of the wafer is polished by the wafer edge polishing drums according to the first and second examples, roundness is enhanced such that the resultant wafer has a shape approximate to a circular shape, as compared to the comparative example, as shown in TABLE 1.

[0061]FIGS. 6 and 7 show results of measurement of profiles of wafers according to TABLE 1 using an EZ300.

[0062]FIG. 6 shows profiles of wafers exhibited after the edge areas of the wafers are polished by respective wafer edge polishing drums according to the comparative example and the first and second examples. FIG. 7 shows an enlarged view of respective portions of the edge front areas in FIG. 6.

[0063]Referring to FIGS. 6 and 7, it can be seen that an enhancement in wafer edge front area profile, that is, an enhancement in flatness and an increase in radius of roundness according to an increase in polishing amount, is higher in the first example than in the comparative example, and is higher in the second example than in the first example.

[0064]FIG. 8 is a diagram showing the entire configuration of the edge polishing equipment for wafers.

[0065]A wafer is loaded in the wafer edge polishing equipment after completion of an edge grinding process. In the wafer edge polishing equipment, a notch polishing process is first performed for the loaded wafer.

[0066]Thereafter, edge polishing may be performed. For example, wafer edge polishing may be carried out in an order of edge polishing, front polishing, and back polishing, as shown in FIG. 8.

[0067]That is, when the wafer edge area is divided into an edge of a side surface, an edge front bevel of a front surface, and an edge back bevel of a back surface, the edge polishing is a process for polishing the side surface of the wafer edge area, the front polishing is a process for polishing the edge front bevel, and the back polishing is a process for polishing the edge back bevel.

[0068]The wafer edge polishing drum according to the above-described embodiment first polishes the edge front level of the wafer. After polishing of the edge front bevel, the wafer is vertically inverted, and is then disposed at the wafer support chuck. When polishing is again performed in this state, the edge back level of the wafer is polished.

[0069]After the edge polishing process is completed, the wafer is unloaded, and an additional process for manufacture of a wafer may be performed.

[0070]When the edge of the wafer is polished using the wafer edge polishing drum according to the above-described embodiment of the present disclosure and the wafer edge polishing equipment including the same, the edge front bevel and the edge back level of the wafer may be uniformly polished by virtue of the inner surface of the polishing part, in particular, the first area and the second area having different angles at the second surface of the inner surface, and tilting of a first rotation axis, about which the polishing part rotates, with respect to a second rotation axis, about which the wafer rotates. Accordingly, it may be possible to control variability of a polishing amount and, as such, to reduce shape variability of the wafer after completion of polishing.

[0071]Although the foregoing description has been given mainly in conjunction with embodiments, these embodiments are only illustrative without limiting the disclosure. Those skilled in the art to which the present disclosure pertains can appreciate that various modifications and applications illustrated in the foregoing description may be possible without changing essential characteristics of the embodiments. Therefore, the above-described embodiments should be understood as exemplary rather than limiting in all aspects. In addition, the scope of the present disclosure should also be interpreted by the claims below rather than the above detailed description. All modifications or alterations as would be derived from the equivalent concept intended to be included within the scope of the present disclosure should also be interpreted as falling within the scope of the disclosure.