Wafer Edge Polishing Drum and Wafer Edge Polishing Equipment Including the Same

This application claims the benefit of Korean Patent Application No. 10-2024-0039272, filed on Mar. 21, 2024, which is hereby incorporated by reference as if fully set forth herein.

The present disclosure relates to a wafer edge polishing drum and wafer edge polishing equipment including the same, and more particularly to a wafer edge polishing drum and wafer edge polishing equipment including the same capable of polishing an edge front bevel and an edge back bevel in an edge area of a wafer.

A single-crystal silicon wafer may be manufactured through a single-crystal growth process, a slicing process of slicing an ingot to obtain a thin disc-shaped wafer, an edge grinding process of grinding an edge of the wafer obtained through the slicing process in order to prevent fracture or distortion of the wafer, a lapping process of removing damage due to mechanical machining remaining on the wafer in order to improve flatness of the wafer, a polishing process of mirror-polishing the wafer, and a cleaning process of removing a polishing agent and foreign matter from the polished wafer.

After the edge grinding process described above, an edge polishing process is performed to mirror-polish a rough surface in the edge area of the wafer.

Typically, an edge area of a wafer is polished using a device called an edge polishing drum. The edge of the wafer having undergone an edge grinding process may have a non-uniform shape, i.e., variation in shape. Thus, although edge polishing is performed by an edge polishing drum having a uniform shape, the polished edge area of the wafer may have variation in shape.

Accordingly, the present disclosure is directed to a wafer edge polishing drum and wafer edge polishing equipment including the same that substantially obviate one or more problems due to limitations and disadvantages of the related art.

Embodiments provide a wafer edge polishing drum and wafer edge polishing equipment including the same capable of uniformly polishing an edge area of a wafer.

Additional advantages, objectives, and features of the disclosure will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the disclosure. The objectives and other advantages of the disclosure may be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.

To achieve these objects and other advantages and in accordance with the purpose of the disclosure, as embodied and broadly described herein, a wafer edge polishing drum includes a body part having a disc shape and a polishing part extending from a peripheral portion of a first surface of the body part while being inclined with respect to the first surface of the body part, wherein the polishing part includes an inner surface surrounding a polishing area adjacent to the first surface of the body part, the inner surface of the polishing part includes a first surface extending from the first surface of the body part and a second surface formed so as to be brought into contact with an edge area of a wafer, the second surface of the polishing part has a second angle with respect to the first surface of the body part, and the second angle is variable.

The first surface of the polishing part may have a first angle with respect to the first surface of the body part, and the first angle may be larger than the second angle.

The wafer edge polishing drum may have a first rotation axis, and the first rotation axis may be perpendicular to the first surface of the body part.

The wafer edge polishing drum may further include a plurality of polishing pads provided on the second surface of the polishing part, and the plurality of polishing pads may be spaced apart from each other.

In another aspect of the present disclosure, wafer edge polishing equipment includes the above-described wafer edge polishing drum and a wafer support chuck disposed so as to face the first surface of the body part of the wafer edge polishing drum while being spaced apart from the first surface of the body part.

The first rotation axis of the wafer edge polishing drum may be tilted with respect to a second rotation axis of the wafer support chuck.

The second rotation axis may be tilted to a predetermined angle with respect to a direction perpendicular to the first surface of the body part.

It is to be understood that both the foregoing general description and the following detailed description of the present disclosure are exemplary and explanatory and are intended to provide further explanation of the disclosure as claimed.

The present disclosure will now be described more fully hereinafter with reference to the accompanying drawings, in which various embodiments are shown.

The examples, however, may be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be more thorough and complete, and will more fully convey the scope of the disclosure to those skilled in the art.

In addition, relational terms, such as “first”, “second”, “on/upper part/above” and “under/lower part/below”, are used only to distinguish between one subject or element and another subject or element, without necessarily requiring or involving any physical or logical relationship or sequence between the subjects or elements.

The present disclosure provides a wafer edge polishing drum and wafer edge polishing equipment including the same in which an inner surface of a polishing part for polishing an edge area of a wafer, particularly, a second surface of the polishing part that performs a polishing action on the edge area of the wafer through direct friction therewith has a variable angle rather than a fixed angle and a rotation axis of the wafer edge polishing drum is capable of being tilted with respect to the wafer. Accordingly, when the edge of the wafer is polished, the entire edge area of the wafer may be uniformly polished, and thus variation in the amount of polishing may be controlled. As a result, it is possible to manufacture a wafer having an edge having a uniform shape after polishing of the edge.

is a view showing wafer edge polishing equipment according to an embodiment of the present disclosure, andis a view showing a wafer edge polishing drum inin detail.

The wafer edge polishing equipment according to the embodiment of the present disclosure may include a wafer edge polishing drumand a wafer support chuckdisposed so as to face a first surfaceof a body partof the wafer edge polishing drum while being spaced apart therefrom.

The wafer edge polishing drumfor polishing a wafer and the wafer support chuckfor supporting the wafer may be configured to rotate. As shown in, the wafer edge polishing drumand the wafer support chuckmay rotate in the same direction or may rotate in different directions. In this case, a first rotation axis (or first axis) of the wafer edge polishing drummay be tilted with respect to a second rotation axis (or second axis) of the wafer support chuck. As shown in, the first rotation axis may be tilted to, for example, 2 degrees (°).

In addition, the second rotation axis may be tilted to a predetermined angle with respect to a direction perpendicular to the first surfaceof the body partof the wafer edge polishing drum. As described above and shown in, the predetermined angle may be 2 degrees (°).

The wafer support chuckincludes a rotation bodyand a support body. The rotation bodyis a part that rotates about the above-described second rotation axis, and the support bodyis a part that rotates along with rotation of the rotation bodyand supports the wafer.

In addition, the polishing drumfurther includes a polishing partprovided at the body part. The polishing parthas an inner surface facing the wafer, and the inner surface includes a first surface, a second surface, and a third surface. The configuration of the polishing drumwill be descried below in more detail with reference to.

A polishing padfor polishing the wafer through friction therewith may be provided on the second surface. When polishing the edge of the wafer, mechanical polishing using friction with the polishing pad and chemical polishing using polishing slurry may be performed simultaneously.

As shown in, the wafer edge polishing drum according to the embodiment of the present disclosure may include a disc-shaped body parthaving a predetermined thickness and a polishing part.

The body partmay include a first surfacefacing the wafer, which is an object to be polished, and a second surfaceformed opposite the first surface. The first rotation axis (or first axis), about which the wafer edge polishing drum and the body partrotate, may be perpendicular to at least one of the first surfaceor the second surfaceof the body part.

The polishing partmay extend from a peripheral portion of the first surfaceof the body partwhile being inclined with respect to the first surface. A space in which the wafer is polished is defined as a “polishing area”. The polishing area may be provided adjacent to the first surfaceof the body part, and the inner surface of the polishing partmay be disposed so as to surround the polishing area.

The inner surface of the polishing partmay include first surfacesandsecond surfacesandand third surfacesandThe first surfacesandmay extend from the first surfaceof the body part, the second surfacesandmay extend from the first surfacesandso as to be brought into contact with the edge area of the wafer, which is an object to be polished, and the third surfacesandmay extend from the second surfacesandso as to be located at a position farther outward than the edge area of the wafer.

Two first surfacesandtwo second surfacesandand two third surfacesandare illustrated inas being located on the left and right sides. In detail, the two first surfacesandmay be symmetrical to each other with respect to the first rotation axis (or first axis), and the two third surfacesandmay be symmetrical to each other with respect to the first rotation axis (or first axis). The first surfacesandmay form a first angle θ, which is constant, with the first surfaceof the body part, and the third surfacesandmay form a third angle θ, which is constant, with the first surfaceof the body part.

The second surfacesandmay form second angles θand θwith the first surfaceof the body parton the right side and the left side, respectively, based on, and the second angles θand θmay be different from each other. That is, the second surfacesandmay have the second angles θand θ, which are variable, with respect to the first surfaceof the body part, respectively. For example, the second angles θand θmay range from 18 degrees (°) to 30 degrees (°).

The first angle θmay be larger than the second angles θand θ, and the second angles θand θmay be larger than the third angle θ. That is, when the inner surface extends from the first surfaceof the body part, the first surfacesandmay extend at the largest angle with respect to the first surface, and the third surfacesandmay extend at the smallest angle with respect to the first surface.

is a view showing the inner surface of the polishing part of the wafer edge polishing drum inin detail.illustrates a perspective view of the first surface, the second surface, and the third surfaceconstituting the inner surface of the polishing part. The second angles θand θmay be formed so as to be continuously varied within a range of 18 degrees (°) to 30 degrees (°). For example, when the second angle θis 18 degrees (°) and the second angle θis 30 degrees (°), the angle formed by the second surfacemay be continuously varied from 18 degrees (°), which is the second angle θ, to 30 degrees (°), which is the second angle θ, between two opposite points of the second surface.

is a plan view of the inner surface of the polishing part of the wafer edge polishing drum in.

As shown in, the inner surface of the polishing partmay include the first to third surfaces,, and, and the polishing padmay be provided on the second surface. In particular, as shown in, the polishing padmay be provided in plural, and the plurality of polishing padsmay be spaced apart from each other.

is a view showing the wafer polishing action performed by the inner surface of the polishing part of the wafer edge polishing drum in.

shows a process in which an edge front bevel, which is an upper portion of the edge area of the wafer, is polished by the two second surfacesandincluded in the inner surface of the above-described polishing part. A portion that is polished by the second surfaceis indicated by “A”, and a portion that is polished by the second surfaceis indicated by “B”.

As described above, the first rotation axis and the second rotation axis may be tilted, and the second surface of the polishing part may have the second angle that is variable. Therefore, portion “A” and portion “B” of the edge front bevel of the wafer may be polished. In particular, as described above, because the angle formed by the second surface included in the inner surface of the polishing part with respect to the first surface of the body part is continuously varied, for example, from 18 degrees (°) to 30 degrees (°), various portions of the edge front bevel of the wafer other than portion “A” and portion “B” shown inmay also be polished.

is a diagram showing overall configuration including the wafer edge polishing equipment in.

A wafer having undergone an edge grinding process is loaded in the wafer edge polishing equipment, and a wafer notch polishing process is first performed.

Then, the edge of the wafer is polished. For example, as shown in, an edge polishing process, a front polishing process, and a back polishing process may be performed in that order.

The edge area of the wafer may be divided into a lateral edge corresponding to a lateral portion of the edge area, an edge front bevel corresponding to an upper portion of the edge area, and an edge back bevel corresponding to a lower portion of the edge area. The edge polishing process is a process of polishing the lateral edge, the front polishing process is a process of polishing the edge front bevel, and the back polishing process is a process of polishing the edge back bevel.

The wafer edge polishing drum according to the above-described embodiment polishes the edge front bevel of the wafer. After the edge front bevel of the wafer is polished, the wafer is flipped upside down and placed on the wafer support chuck, and then is polished again, so the edge back bevel of the wafer is polished.

When the edge polishing process is completed, the wafer may be unloaded, and an additional process for manufacturing the wafer may be performed.

When the edge of the wafer is polished using the wafer edge polishing drum and the wafer edge polishing equipment including the same according to the embodiment of the present disclosure described above, the edge front bevel and the edge back bevel of the wafer may be uniformly polished due to the variable angle of the inner surface of the polishing part, particularly, the second surface of the polishing part, and tilting of the second rotation axis about which the wafer is rotated and the first rotation axis about which the polishing part is rotated. Accordingly, it is possible to control variation in the amount of polishing and to reduce variation in the shape of the edge area of the wafer after the process.

As is apparent from the above description, a wafer edge polishing drum and wafer edge polishing equipment including the same according to the present disclosure may uniformly polish an edge front bevel and an edge back bevel of a wafer due to a variable angle of an inner surface of a polishing part, particularly, a second surface of the polishing part, and tilting of a second rotation axis about which the wafer is rotated and a first rotation axis about which the polishing part is rotated, thereby controlling variation in the amount of polishing and reducing variation in the shape of the edge area of the wafer after the process.

Even though the embodiments of the present disclosure have been described in more detail with reference to the accompanying drawings, the present disclosure is not necessarily limited to these embodiments, and may be variously modified and implemented without departing from the technical spirit of the present disclosure. Therefore, the embodiments disclosed herein are not intended to limit the technical spirit of the present disclosure, but to describe the technical spirit, and the scope of the technical spirit of the present disclosure is not limited by these embodiments. Accordingly, it should be understood that the embodiments described above are illustrative in all respects and not restrictive. The protection scope of the present disclosure should be construed according to the scope of the claims, and all technical ideas within the scope equivalent thereto should be construed as being included in the scope of the present disclosure.