BRUSH ASSEMBLY AND WAFER CLEANING DEVICE INCLUDING THE SAME

A brush assembly includes a first brush including a first body that is cylindrical, and a first vertical gear connected to a surface of the cylindrical first body that faces a third body, the first vertical gear being configured to rotate in a first vertical direction, a second brush including a first horizontal gear configured to rotate in a first horizontal direction and a second body connected to a lower portion of the first horizontal gear and rotatably connected to the first body, and a third brush including a second vertical gear connected to a surface of the third body that faces the first body, the second vertical gear being configured to rotate in a second vertical direction that is opposite to the first vertical direction, where the first horizontal gear is engaged with a lower portion of the first vertical gear.

CROSS-REFERENCE TO RELATED APPLICATION

This application is based on and claims priority to Korean Patent Application No. 10-2023-0024390, filed on Feb. 23, 2023, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference in its entirety.

BACKGROUND

Example embodiments of the disclosure relate to a brush assembly and a wafer cleaning device including the same.

2. Description of the Related Art

An integrated circuit may be generally formed by successive deposition of a conductor, a semiconductor, and an insulator on a substrate (e.g., a silicon wafer). After each layer is deposited, each layer is etched to provide a circuit characteristic. As a series of layers are continuously deposited and etched, an exposed surface of the wafer becomes increasingly rough, and a chemical-mechanical polishing (CMP) process may be used to smooth the wafer.

After the CMP process, an impurity (a particle) such as a polishing by-product, a slurry, or the like remains on a surface of the wafer. Therefore, a cleaning process is performed on the surface of the wafer to remove the particle such as the polishing by-product, the slurry, or the like.

The cleaning process may be performed using a brush configured to remove particles. However, the brush used in a related art cleaning processes may have issues in which uniform cleaning is not performed because an area in which the brush contacts the wafer is not uniform.

Information disclosed in this Background section has already been known to or derived by the inventors before or during the process of achieving the embodiments of the present application, or is technical information acquired in the process of achieving the embodiments. Therefore, it may contain information that does not form the prior art that is already known to the public.

SUMMARY

One or more example embodiments provide a brush assembly capable of uniformly cleaning a surface of a wafer and a wafer cleaning device including the brush assembly.

According to an aspect of an example embodiment, a brush assembly may include a first brush including a first body that is cylindrical, and a first vertical gear connected to a surface of the cylindrical first body that faces a third body, the first vertical gear being configured to rotate in a first vertical direction, a second brush including a first horizontal gear configured to rotate in a first horizontal direction and a second body connected to a lower portion of the first horizontal gear and rotatably connected to the first body, and a third brush including a second vertical gear connected to a surface of the third body that faces the first body, the second vertical gear being configured to rotate in a second vertical direction that is opposite to the first vertical direction, where the first horizontal gear may be engaged with a lower portion of the first vertical gear and a lower portion of the second vertical gear at right angles.

According to an aspect of an example embodiment, a wafer cleaning device may include a first brush assembly provided on an upper surface of a wafer, and a second brush assembly provided on a lower surface of the wafer and facing the first brush assembly, where the first brush assembly may include a first brush including a first body that is cylindrical and a first vertical gear that is connected to a surface of the first body that faces a third body, the first vertical gear being configured to rotate in a first vertical direction, a second brush including a first horizontal gear configured to rotate in a first horizontal direction and a second body connected to a lower portion of the first horizontal gear and rotatably connected to the first body, and a third brush including a second vertical gear connected to a surface of the third body that faces the first body, the second vertical gear being configured to rotate in a second vertical direction that is opposite to the first vertical direction, where the first horizontal gear may be engaged with a lower portion of the first vertical gear and a lower portion of the second vertical gear at right angles and the second brush assembly may include a fourth brush comprising a cylindrical body configured to rotate in the second vertical direction.

According to an aspect of an example embodiment, a wafer cleaning device may include a first brush assembly provided on an upper surface of a wafer and a second brush assembly provided on a lower surface of the wafer and facing the first brush assembly, where the first brush assembly may include a first brush including a first body that is cylindrical and a first vertical gear connected to a surface of the first body that faces a third body, the first vertical gear being configured to rotate in a first vertical direction, a second brush including a first horizontal gear configured to rotate in a first horizontal direction and a second body connected to a lower portion of the first horizontal gear and rotatably connected to the first body, and a third brush including a second vertical gear connected to a surface of the third body that faces the first body, the third brush being configured to rotate in a second vertical direction that is opposite to the first vertical direction, where the second brush assembly may include a fourth brush including a fourth body that is cylindrical and a third vertical gear connected to a surface of the fourth body that faces a sixth body, the third vertical gear being configured to rotate in the second vertical direction, a fifth brush including a third horizontal gear configured to rotate in a second horizontal direction that is opposite to the first horizontal direction and a fifth body connected to an upper portion of the third horizontal gear and rotatably connected to the fourth body, and a sixth brush including a fourth vertical gear connected to a surface of the sixth body that faces the fourth body, the fourth vertical gear being configured to rotate in the first vertical direction, and where the third horizontal gear may be engaged with an upper portion of the third vertical gear and an upper portion of the fourth vertical gear at right angles.

DETAILED DESCRIPTION

Hereinafter, example embodiments of the disclosure will be described in detail with reference to the accompanying drawings. The same reference numerals are used for the same components in the drawings, and redundant descriptions thereof will be omitted. The embodiments described herein are example embodiments, and thus, the disclosure is not limited thereto and may be realized in various other forms.

In order to clearly describe the present disclosure, parts or portions that are irrelevant to the description are omitted, and identical or similar constituent elements throughout the specification are denoted by the same reference numerals.

Further, in the drawings, the size and thickness of each element are arbitrarily illustrated for ease of description, and the present disclosure is not necessarily limited to those illustrated in the drawings. In the drawings, the thicknesses of layers, films, panels, regions, areas, etc., are exaggerated for clarity. In the drawings, for ease of description, the thicknesses of some layers and areas are exaggerated.

Further, throughout the specification, the phrase “in a plan view” or “on a plane” means viewing a target portion from the top, and the phrase “in a cross-sectional view” or “on a cross-section” means viewing a cross-section formed by vertically cutting a target portion from the side.

After a chemical-mechanical polishing (CMP) process, an impurity (a particle) such as a polishing by-product, a slurry, or the like may remain on a surface of the wafer.

However, in related art, a cylindrical brush has a problem in which uniform cleaning is not performed because an area in which the brush touches (or contacts) a wafer is not uniform during the cleaning process. Specifically, when the cleaning process is performed using the cylindrical brush, more contact is made with a central surface of the wafer than with an edge of the wafer. In particular, when more contact is made with the central surface of the wafer in a CMP process of a metal thin film, an oxide film may be peeled off such that corrosion of the metal thin film may occur. The brush assembly according to embodiments disclosed herein may include a uniform contact region in which the brush assembly contacts the surface of the wafer when the cleaning process is performed such that the cleaning device is capable of performing uniform cleaning while having excellent cleaning power.

FIG.1is a diagram illustrating a wafer cleaning device according to an embodiment. The method for removing the particle remaining on the wafer using a brush as shown inFIG.1is an effective method in terms of cleaning power.

Referring toFIG.1, the wafer cleaning device501according to an embodiment may be used in a cleaning process of a wafer300(e.g., a semiconductor wafer).

In the wafer cleaning device501, a cleaning liquid may be supplied to the surface of the wafer300in a state in which the wafer300is rotated in a horizontal direction, and a first brush assembly101disposed on an upper surface of the wafer300and a second brush assembly200disposed on a lower surface of the wafer300may also be rotated to contact the surface of the wafer300. Accordingly, the particle remaining on the surface of the wafer300may be removed.

A total length of each of the first brush assembly101and the second brush assembly200may be slightly longer than a diameter of the wafer300.

For example, the cleaning liquid supplied during cleaning of the wafer300may be one of ultrapure water (DI water), ammonia water (NH4OH), and hydrofluoric acid (HF), but the present disclosure is not limited thereto.

Since the wafer300and the first and second brush assemblies101and200rotate together as described above, efficient cleaning of the wafer300may be achieved.

The brush assembly101according to an embodiment may include a first brush110, a second brush120, and a third brush130.

The first brush110may include a first body111rotating in a first vertical direction S1. The first body111may have a cylindrical shape having a predetermined height.

A first vertical gear111arotating in the first vertical direction S1 may be attached to a surface of the first body111facing a third body131.

A core portion that is a rotatable member may be disposed inside the first body111, and an external movable portion may be connected to the core portion (or a core part) such that the first brush110is rotatable in the first vertical direction S1. Accordingly, the first body111and the first vertical gear111amay be rotated together by operating the external movable portion (or an external movable part) connected to the core portion disposed inside the first body111.

The third brush130may include the third body131rotating in a second vertical direction S2. The third body131may have a cylindrical shape having a predetermined height. In some embodiments, the first body111and the third body131may have the same height, but the present disclosure is not limited thereto.

A second vertical gear131arotating in the second vertical direction S2 may be attached to a surface of the third body131that faces the first body111.

A core portion that is a rotatable member may be disposed inside the third body131, and an external movable portion may be connected to the core portion such that the third brush130is rotatable in the second vertical direction S2. Accordingly, the third body131and the second vertical gear131amay be rotated together by operating the external movable portion (or an external movable part) connected to the core portion disposed inside the third body131.

In this case, rotation in the first vertical direction S1 may be counterclockwise with respect to a yz plane, and rotation in the second vertical direction S2 may be clockwise with respect to the yz plane. That is, a rotation direction that is the first vertical direction S1 and a rotation direction that is the second vertical direction S2 may be opposite to each other.

The second brush120may include a first horizontal gear122aand a second body123.

The first horizontal gear122amay rotate in a first horizontal direction S3 by meshing with a lower portion of the first vertical gear111aand a lower portion of the second vertical gear131aat right angles. In some embodiments, rotation in the first horizontal direction S3 may be clockwise with respect to an xy plane.

The second body123may be attached to a lower portion of the first horizontal gear122a, and may be rotatably connected to the first body111and the third body131. The second body123may have a low cylindrical shape, and a lower surface of the second body123may be disposed parallel to the wafer300. Accordingly, a side surface of the second body123and a side surface of the first body111or the third body131may be perpendicular to each other. In this case, a height of the second body123is not limited when the height of the second body123is thicker than a thickness of the wafer300.

In some embodiments, the first brush110, the second brush120, and the third brush130may be simultaneously rotated by operating the external movable portion of the first brush110to rotate the first vertical gear111aattached to the first body111.

Alternatively, the first brush110, the second brush120, and the third brush130may be simultaneously rotated by operating the external movable portion of the third brush130to rotate the second vertical gear131aattached to the third body131. That is, a movable portion for rotation may not be separately connected to the second brush120.

A central axis (e.g., an axis of rotation) of the first brush110and a central axis of the third brush130may be roughly orthogonal to a central axis (a center of rotation) of the wafer300, and a central axis of the second brush120may be roughly coincident with the central axis of the wafer300. In addition, the total length of the first brush assembly101may be longer than the diameter of the wafer300. Accordingly, as the first brush110, the second brush120, and the third brush130rotate, an entire upper surface of the wafer300may be simultaneously cleaned.

On the other hand, the second brush120may further include a first vertical axel125that passes through a center of the first horizontal gear122aand is disposed on a central surface of the second body123.

The first vertical axel125may support the second body123of the second brush120, and may simultaneously adjust a pressure applied to the second brush120in a vertical direction P1. That is, when a region where the second body123contacts the upper surface of the wafer300and a region where the first body111and the third body131contact the upper surface of the wafer300are not uniform in the cleaning process, contact uniformity may be secured by controlling a degree of pressurization of the first vertical axel125.

Specifically, when the first brush assembly101contacts a central portion of the wafer300more than an edge portion of the wafer300, a pressure applied to the second body123using the first vertical axel125may be reduced. Thus, a contact region in which a central surface of the wafer300is contacted by the second body123may be adjusted to be balanced with a contact region in which an edge surface of the wafer is contacted by the first body111and the third body131.

In some embodiments, the core portions of the first body111and the third body131may be made of a material such as Teflon. For example, the first body111, the second body123, and the third body131may be made of polyvinyl alcohol (PVA).

A plurality of protrusions may be included on outer circumferential surfaces of the first and third bodies111and131and on a surface of the second body123that contacts the wafer300. The plurality of protrusions may be manufactured by a method such as three-dimensional (3D) printing using the same material as that of each of the first body111, the second body123, and the third body131. After the first body111, the second body123, and the third body131are manufactured, a plurality of protrusions may be additionally attached to side surfaces of the first body111and the third body131. When the protrusions are included, cleaning power may be further improved.

In the present specification, a region where the second body123contacts a surface of the wafer300may be defined as a central portion of an upper surface, and a region where the first body111and the third body131contact the surface of the wafer300may be defined as an edge portion of the upper surface.

On the other hand, in the first brush assembly101, the first vertical gear111a, the second vertical gear131a, and the first horizontal gear122amay have the same diameter. In addition, teeth sizes of the first vertical gear111a, the second vertical gear131a, and the first horizontal gear122amay be the same. In this case, a rotational speed (or a rotational velocity) in the vertical direction and a rotational speed in the horizontal direction may be the same. As used herein, the term “same diameter” in reference to gears, teeth, or other components may indicate that the objects have an exact same diameter, substantially the same diameter and/or a substantially similar overall shape and size, as will be understood by one of ordinary skill in the art from the disclosure herein.

Accordingly, the first body111, the third body131, and the second body123may rotate at the same speed to clean the surface of the wafer300. In this case, there may be a difference in shapes of the first and third bodies111and131and the second body123, such that when the cleaning process is performed by applying the first brush assembly101, there may be a difference in frictional forces generated by contact with a central portion and an edge portion of the wafer300. That is, a problem of contact imbalance in which the first brush assembly101contacts the central portion of the surface of the wafer300more than the edge portion of the surface of the wafer300may be solved or mitigated using the difference in frictional forces.

In addition, when contact imbalance occurs, by monitoring the contact regions of the central portion and the edge portion of the wafer300while the cleaning process is performed, a pressure applied to the second body123may be controlled in the vertical direction P1 using the first vertical axel125such that cleaning may be uniformly adjusted.

The cleaning device501may include the first brush assembly101contacting an upper surface of the wafer300and the second brush assembly200contacting a lower surface of the wafer300. The first brush assembly101and the second brush assembly200may be disposed at a position corresponding to each other with respect to the wafer300.

A core portion that is a rotatable member may be disposed inside the second brush assembly200, and an external movable portion may be connected to the core portion such that the second brush assembly is rotatable in the second vertical direction S2. Rotation in the second vertical direction S2 may be clockwise with respect to the yz plane. A central axis of the second brush assembly200may be roughly orthogonal to the central axis of the wafer300at a position where the second brush assembly200corresponds to the first brush assembly101. In addition, the entire length of the second brush assembly200may be longer than the diameter of the wafer300. Materials constituting the core portion and a body of the second brush assembly200may be the same as those described for the first brush assembly101. In addition, a plurality of protrusions may be included on the outer circumferential surface of the second brush assembly200.

Since the cleaning device501includes the first brush assembly101and the second brush assembly200, upper and lower surfaces of the wafer300may be cleaned simultaneously.

Hereinafter, other embodiments will be described with the drawings. In the embodiments described with reference toFIGS.2-12, the same or similar components as those described with respect toFIG.1may be included, and repeated descriptions may be omitted.

FIG.2is a diagram illustrating a wafer cleaning device according to an embodiment. InFIG.2, diameters of a first vertical gear, a second vertical gear, and a first horizontal gear of the first brush assembly may be different from those shown inFIG.1.

Specifically, referring toFIG.2, in the cleaning device502, the first brush assembly102may include the first vertical gear111c, the second vertical gear131c, and the first horizontal gear122b.

The diameters of the first vertical gear111cand the second vertical gear131cmay be the same. In addition, the diameter of the first horizontal gear122bmay be greater than the diameter of the first vertical gear111cor the second vertical gear131c.

In some embodiments, teeth sizes of the first vertical gear111c, the second vertical gear131c, and the first horizontal gear122bmay be the same.

In this case, diameters and rotational speeds of the first and second vertical gears111cand131cand the first horizontal gear122bmay be defined by Equation (1).

Accordingly, the diameters of the first and second vertical gears111cand131cand the diameter of the first horizontal gear122bmay be appropriately designed using Equation (1).

In some embodiments, since the diameters of the first and second vertical gears111cand131care the same, rotational speeds of the first body111and the third body131may be the same. In addition, since the diameter of the first horizontal gear122bis larger than the diameters of the first and second vertical gears111cand131c, the rotational speeds of the first body111and the third body131may be faster than a rotational speed of the second body123.

Therefore, a difference in shape and rotational speed between the first body111, the third body131, and the second body123may be used in the cleaning process such that there may be a difference in frictional forces generated by contact with a central portion and an edge portion of the surface of the wafer300. Therefore, a problem of contact imbalance in which the first brush assembly102contacts the central portion of the surface of the wafer300more than the edge portion of the surface of the wafer300may be solved or mitigated using the difference in frictional forces.

FIG.3is a diagram illustrating a wafer cleaning device according to an embodiment. InFIG.3, diameters of a first vertical gear, a second vertical gear, and a first horizontal gear of the first brush assembly may be different from those shown inFIG.1.

Specifically, referring toFIG.3, in the cleaning device503, the first brush assembly103may include the first vertical gear111b, the second vertical gear131b, and the first horizontal gear122c.

The diameters of the first vertical gear111band the second vertical gear131bmay be the same. In addition, the diameter of the first horizontal gear122cmay be smaller than the diameter of the first vertical gear111bor the second vertical gear131b.

In some embodiments, teeth sizes of the first vertical gear111b, the second vertical gear131b, and the first horizontal gear122bmay be the same.

In this case, diameters and rotational speeds of the first and second vertical gears111band131band the first horizontal gear122cmay be defined by Equation (1) as described above.

Accordingly, the diameters of the first and second vertical gears111band131band the diameter of the first horizontal gear122cmay be appropriately designed using Equation (1).

In some embodiments, since the diameters of the first and second vertical gears111band131bare the same, rotational speeds of the first body111and the third body131may be the same. In addition, since the diameter of the first horizontal gear122cis smaller than the diameters of the first and second vertical gears111band131b, the rotational speeds of the first body111and the third body131may be slower than a rotational speed of the second body123.

Therefore, a difference in shape and rotational speed between the first body111, the third body131, and the second body123may be used in the cleaning process such that there may be a difference in frictional forces generated by contact with a central portion and an edge portion of the surface of the wafer300. Therefore, a problem of contact imbalance in which the first brush assembly103contacts the central portion of the surface of the wafer300more than the edge portion of the surface of the wafer300may be solved or mitigated using the difference in frictional forces.

FIG.4is a diagram illustrating a wafer cleaning device according to an embodiment.FIG.4differs fromFIG.1in that a second horizontal gear and a first support body are further included in the second brush.

Referring toFIG.4, in the cleaning device504, the second brush120of the first brush assembly104may further include the second horizontal gear122aathat is engaged with upper portions of the first and second vertical gears111aand131aat right angles to rotate in a second horizontal direction S4 that is opposite to the first horizontal direction S3, and the first support body124attached to an upper portion of the second horizontal gear122aa. In this case, rotation in the first horizontal direction S3 may be clockwise with respect to the xy plane, and rotation in the second horizontal direction S4 may be counterclockwise.

In some embodiments, the first support body124may rotate in an opposite direction to the second body123, but may not contribute to cleaning of the wafer300. Specifically, the first support body124may uniformly maintain a pressure applied from the first brush110and the third brush130. Thus, the first support body124may serve to support the second brush120such that the same pressure is applied to upper and lower portions of the second brush120in a horizontal direction. Accordingly, the first support body124may have the same shape as that of the second body123, and may have the same diameter and thickness as those of the second body123.

The first vertical axel125passes through centers of the first support body124, the second horizontal gear122aa, and the first horizontal gear122a, and is disposed on a central surface of the second body123.

On the other hand, in the first brush assembly104, diameters of the first vertical gear111a, the second vertical gear131a, the first horizontal gear122a, and the second horizontal gear122aamay be the same. In addition, teeth sizes of the first vertical gear111a, the second vertical gear131a, the first horizontal gear122a, and the second horizontal gear122aaare the same. Therefore, a rotational speed in the vertical direction and a rotational speed in the horizontal direction may be the same.

FIG.5is a diagram illustrating a wafer cleaning device according to an embodiment. InFIG.5, diameters of a first vertical gear, a second vertical gear, a first horizontal gear, and a second horizontal gear of the first brush assembly may be different from those ofFIG.4.

Specifically, referring toFIG.5, in the cleaning device505, the first brush assembly105may include the first vertical gear111c, the second vertical gear131c, the first horizontal gear122b, and the second horizontal gear122bb.

The diameters of the first vertical gear111cand the second vertical gear131cmay be the same.

In addition, the diameters of the first horizontal gear122band the second horizontal gear122bbmay be the same.

However, the diameter of the first vertical gear111cor the second vertical gear131cmay be smaller than the diameter of the first horizontal gear122bor the second horizontal gear122bb.

Teeth sizes of the first vertical gear111c, the second vertical gear131c, the first horizontal gear122b, and the second horizontal gear122bbmay be the same.

In this case, diameters and rotational speeds of the first and second vertical gears111cand131cand the first and second horizontal gears122band122bbmay be defined by Equation (2).

Therefore, the diameters of the first and second vertical gears111cand131cand the diameters of the first and second horizontal gears122band122bbmay be appropriately designed using Equation (2).

Since the diameters of the first and second vertical gears111cand131care the same, rotational speeds of the first body111and the third body131may be the same. In addition, since the diameters of the first horizontal gear122band the second horizontal gear122bbare larger than the diameters of the first and second vertical gears111cand131c, the rotational speeds of the first body111and the third body131may be faster than a rotational speed of the second body123.

Therefore, a difference in shape and rotational speed between the first body111, the third body131, and the second body123may be used in the cleaning process such that there may be a difference in frictional forces generated by contact with a central portion and an edge portion of the surface of the wafer300. Thus, a problem of contact imbalance in which the first brush assembly105contacts the central portion of the surface of the wafer300more than the edge portion of the surface of the wafer300may be solved or mitigated using the difference in frictional forces.

FIG.6is a diagram illustrating a wafer cleaning device according to an embodiment. InFIG.6, diameters of a first vertical gear, a second vertical gear, a first horizontal gear, and a second horizontal gear of the first brush assembly are different from those ofFIG.3.

Specifically, referring toFIG.6, in the cleaning device506, the first brush assembly106may include the first vertical gear111b, the second vertical gear131b, the first horizontal gear122c, and the second horizontal gear122cc.

The diameters of the first vertical gear111band the second vertical gear131bmay be the same.

In addition, the diameters of the first horizontal gear122cand the second horizontal gear122ccmay be the same.

However, the diameter of the first vertical gear111bor the second vertical gear131bmay be greater than the diameter of the first horizontal gear122cor the second horizontal gear122cc.

In some embodiments, teeth sizes of the first vertical gear111b, the second vertical gear131b, the first horizontal gear122c, and the second horizontal gear122ccmay be the same.

In this case, diameter and rotational speeds of the first and second vertical gears111band131band the first and second horizontal gears122cand122ccmay be defined by Equation (2) as described above.

Therefore, the diameters of the first and second vertical gears111band131band the diameters of the first and second horizontal gears122cand122ccmay be appropriately designed using Equation (2).

In some embodiments, since the diameters of the first and second vertical gears111band131bare the same, rotational speeds of the first body111and the third body131may be the same. In addition, since the diameters of the first horizontal gear122cand the second horizontal gear122ccare smaller than the diameters of the first and second vertical gears111band131b, the rotational speeds of the first body111and the third body131may be slower than a rotational speed of the second body123.

Therefore, a difference in shape and rotational speed between the first body111, the third body131, and the second body123may be used in the cleaning process such that there may be a difference in frictional forces generated by contact with a central portion and an edge portion of the surface of the wafer300. Thus, a problem of contact imbalance in which the first brush assembly106contacts the central portion of the surface of the wafer300more than the edge portion of the surface of the wafer300may be solved or mitigated using the difference in frictional forces.

FIG.7is a diagram illustrating a wafer cleaning device according to an embodiment.FIG.7is different fromFIG.1in that the second brush assembly includes a fourth brush, a fifth brush, and a sixth brush.

Referring toFIG.7, the second brush assembly201may include the fourth brush210, the fifth brush220, and the sixth brush230.

The fourth brush210may include a fourth body211rotating in the second vertical direction S2. The fourth body211may have a cylindrical shape having a predetermined height.

A third vertical gear211arotating in the second vertical direction S2 may be attached to a surface of the fourth body211facing a sixth body231.

A core portion that is a rotatable member may be disposed inside the fourth body211, and an external movable portion may be connected to the core portion such that the fourth brush210is rotatable in the second vertical direction S2. Accordingly, the fourth body211and the third vertical gear211amay be rotated together by operating the external movable portion connected to the core portion disposed inside the fourth body211.

The sixth brush230may include the sixth body231rotating in the first vertical direction S1.

The sixth body231may have a cylindrical shape having a predetermined height. The fourth body211and the sixth body231may have the same height, but the present disclosure is not limited thereto.

A fourth vertical gear231arotating in the first vertical direction S1 may be attached to a surface of the sixth body231facing the fourth body211.

A core portion that is a rotatable member may be disposed inside the sixth body231, and an external movable portion may be connected to the core portion such that the sixth brush230is rotatable in the first vertical direction S1. Accordingly, the sixth body231and the fourth vertical gear231amay be rotated together by operating the external movable portion connected to the core portion disposed inside the sixth body231.

In this case, rotation in the first vertical direction S1 may be counterclockwise with respect to the yz plane, and rotation in the second vertical direction S2 may be clockwise with respect to the yz plane. That is, a rotation direction that is the first vertical direction S1 and a rotation direction that is the second vertical direction S2 may be opposite to each other.

The fifth brush220may include a third horizontal gear222aand a fifth body223.

The third horizontal gear222amay be meshed with lower portions of the third vertical gear211aand the fourth vertical gear231aat right angles to rotate in a second horizontal direction S4. Rotation in the second horizontal direction S4 may be counterclockwise with respect to the xy plane.

The fifth body223may be attached to an upper portion of the third horizontal gear222a, and may be rotatably connected to the fourth body211and the sixth body231. The fifth body223may have a low cylindrical shape, and a lower surface of the fifth body223may be disposed parallel to the wafer300. Accordingly, a side surface of the fifth body223and a side surface of the fourth body211or the sixth body231may be perpendicular to each other. In this case, a height of the fifth body223is not particularly limited given that the height of the fifth body223is thicker than the thickness of the wafer300.

The fourth brush210, the fifth brush220, and the sixth brush230may be simultaneously rotated by operating the external movable portion of the fourth brush210to rotate the third vertical gear211aattached to the fourth body211.

Alternatively, the fourth brush210, the fifth brush220, and the sixth brush230may be simultaneously rotated by operating the external movable portion of the sixth brush230to rotate the fourth vertical gear231aattached to the sixth body231. That is, a movable portion for rotation may not be separately connected to the fifth brush220.

A central axis of the fourth brush210and a central axis of the sixth brush230may be roughly orthogonal to a central axis of the wafer300, and the fourth brush210and the sixth brush230may be parallel to the first brush110and the third brush130of the first brush assembly101.

In addition, a central axis of the fifth brush220may be roughly coincident with the central axis of the wafer300. Therefore, the axis of rotation of the fifth brush220may be roughly coincident with a central axis of the second brush120.

In addition, a total length of the second brush assembly201may be longer than the diameter of the wafer300. Accordingly, as the fourth brush210, the fifth brush220, and the sixth brush230rotate, an entire lower surface of the wafer300may be simultaneously cleaned.

On the other hand, the fifth brush220may further include a second vertical axel225that passes through a center of the third horizontal gear222aand is disposed on a central surface of the fifth body223.

The second vertical axel225may support the fifth body223of the fifth brush220, and may simultaneously adjust a pressure applied to the fifth brush220in a vertical direction P2. That is, when a region where the fifth body223contacts the lower surface of the wafer300and a region where the fourth body211and the sixth body231contact the lower surface of the wafer300are not uniform in the cleaning process, contact uniformity may be secured by controlling a degree of pressurization of the second vertical axel225.

Specifically, when the second brush assembly201contacts a central portion of the lower surface of the wafer300more than an edge portion of the lower surface of the wafer300, a pressure applied to the fifth body223using the second vertical axel225may be reduced. Thus, a contact region in which the central portion of the lower surface of the wafer300is contacted by the fifth body223may be adjusted to be balanced with a contact region in which the edge portion of the lower surface of the wafer is contacted by the fourth body211and the sixth body231.

In some embodiments, materials of the core portions of the fourth body211and the sixth body231and materials of the fourth body211, the fifth body223, and the sixth body231may be the same as those described above (e.g., the same as those ofFIG.1).

In addition, similarly to the first brush assembly101, a plurality of protrusions may be included on outer circumferential surfaces of the fourth body211and the sixth body231and on a surface of the fifth body223that contacts the wafer300. A material and a forming method of the protrusions may be the same as those described in the first embodiment.

In the present specification, a region where the fifth body223contacts a surface of the wafer300may be defined as a central portion of a lower surface, and a region where the fourth body211and the sixth body231contact the surface of the wafer300may be defined as an edge portion of the lower surface.

On the other hand, in the second brush assembly201, the third vertical gear211a, the fourth vertical gear231a, and the third horizontal gear222amay have the same diameter. In addition, teeth sizes of the third vertical gear211a, the fourth vertical gear231a, and the third horizontal gear222amay be the same. In this case, a rotational speed in the vertical direction and a rotational speed in the horizontal direction may be the same.

Accordingly, the fourth body211, the sixth body231, and the fifth body223may rotate at the same speed to clean the lower surface of the wafer300. In this case, there is a difference in shapes of the fourth and sixth bodies211and231and the fifth body223, such that when the cleaning process is performed by applying the second brush assembly201, there may be a difference in frictional forces generated by contact with a central portion and an edge portion of the lower surface of the wafer300. That is, problem of contact imbalance in which the second brush assembly201contacts the central portion of the lower surface of the wafer300more than the edge portion of the lower surface of the wafer300may be solved or mitigated using the difference in frictional forces.

In addition, when contact imbalance occurs by monitoring the contact regions of the central portion and the edge portion of the wafer300while the cleaning process is performed, a pressure applied to the fifth body223may be controlled in the vertical direction P2 using the second vertical axel225such that cleaning may be uniformly adjusted.

The cleaning device507may include the first brush assembly101contacting an upper surface of the wafer300and the second brush assembly201contacting a lower surface of the wafer300, and the first brush assembly101and the second brush assembly201may be disposed at a position corresponding to each other with respect to the wafer300.

Since the cleaning device507includes the first brush assembly101and the second brush assembly201, upper and lower surfaces of the wafer300may be uniformly cleaned at the same time.

FIG.8is a diagram illustrating a wafer cleaning device according to an embodiment. InFIG.8, diameters of a third vertical gear, a fourth vertical gear, and a third horizontal gear of the second brush assembly may be different from those inFIG.7.

Specifically, referring toFIG.8, in the cleaning device508, the second brush assembly202may include the third vertical gear211c, the fourth vertical gear231c, and the third horizontal gear222b.

The third vertical gear211c, the fourth vertical gear231c, and the third horizontal gear222bmay be the same as the first vertical gear111c, the second vertical gear131cof the first brush assembly102of the second embodiment, and the first horizontal gear122band repeated descriptions may be omitted herein.

FIG.9is a diagram illustrating a wafer cleaning device according to an embodiment. InFIG.9, diameters of a third vertical gear, a fourth vertical gear, and a third horizontal gear of the second brush assembly may be different from those inFIG.7.

Specifically, referring toFIG.9, in the cleaning device509, the second brush assembly203may include the third vertical gear211b, the fourth vertical gear231b, and the third horizontal gear222c.

The third vertical gear211b, the fourth vertical gear231b, and the third horizontal gear222cmay be the same as the first vertical gear111b, the second vertical gear131b, and the first horizontal gear122cof the first brush assembly103ofFIG.3, and repeated descriptions may be omitted herein.

FIG.10is a diagram illustrating a wafer cleaning device according to an embodiment.FIG.10may be different from theFIG.7in that the fifth brush may further include a fourth horizontal gear and a second support body.

Referring toFIG.10, in the cleaning device510, the fifth brush220of the second brush assembly204may further include the fourth horizontal gear222aathat is engaged with upper portions of the third and fourth vertical gears211aand231aat right angles to rotate in the second horizontal direction S4 that is opposite to the first horizontal direction S3, and the second support body224attached to a lower portion of the fourth horizontal gear222aa. In this case, rotation in the first horizontal direction S3 may be clockwise with respect to the xy plane, and rotation in the second horizontal direction S4 may be counterclockwise.

The fourth horizontal gear222aaand the second support body224may be the same the second horizontal gear122aaand the first support body124of the first brush assembly104ofFIG.4, and repeated descriptions may be omitted herein.

FIG.11is a diagram illustrating a wafer cleaning device according to an embodiment. InFIG.11, diameters of a third vertical gear, a fourth vertical gear, a third horizontal gear, and a fourth horizontal gear of the second brush assembly may be different from those inFIG.10.

Specifically, referring toFIG.11, in the cleaning device511, the second brush assembly205may include the third vertical gear211c, the fourth vertical gear231c, the third horizontal gear222b, and the fourth horizontal gear222bb.

The third vertical gear211c, the fourth vertical gear231c, the third horizontal gear222b, and the fourth horizontal gear222bbmay be the same the first vertical gear111c, the second vertical gear131c, the first horizontal gear122b, and the second horizontal gear122bbof the first brush assembly105ofFIG.5, and repeated descriptions may be omitted herein.

FIG.12is a diagram illustrating a wafer cleaning device according to an embodiment. In some embodiments, diameters of a third vertical gear, a fourth vertical gear, a third horizontal gear, and a fourth horizontal gear of the second brush assembly may be different from those inFIG.10.

Specifically, referring toFIG.12, in the cleaning device512, the second brush assembly206may include the third vertical gear211b, the fourth vertical gear231b, the third horizontal gear222c, and the fourth horizontal gear222cc.

The third vertical gear211b, the fourth vertical gear231b, the third horizontal gear222c, and the fourth horizontal gear222ccmay be the same the first vertical gear111b, the second vertical gear131b, the first horizontal gear122c, and the second horizontal gear122ccof the first brush assembly106ofFIG.6, and repeated descriptions may be omitted herein.

Each of the embodiments provided in the above description is not excluded from being associated with one or more features of another example or another embodiment also provided herein or not provided herein but consistent with the disclosure.