RETAINER RING FOR POLISHING HEAD

Description

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application claims benefit of priority to Korean Patent Application No. 10-2024-0083396, filed on Jun. 26, 2024 in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference in its entirety.

BACKGROUND

The present inventive concept relates to a retainer ring for a polishing head.

A semiconductor device may be manufactured through various processes such as a photo process, an etching process, a deposition process, a polishing process, and the like, on a substrate. For example, in the case of a polishing process, a chemical mechanical polishing (CMP) process may be used to planarize a surface of the substrate. The chemical mechanical polishing process is a process of planarizing a wafer by causing a chemical reaction with the wafer using slurry, which includes a chemical liquid and solid particles, and a polishing pad, and simultaneously transmitting mechanical force to the wafer. A chemical mechanical polishing device used in the chemical mechanical polishing process includes a retainer ring supporting an edge portion of the wafer to prevent the wafer from being detached from a platen to which a polishing pad is attached during the polishing process.

Generally, during the polishing process, pressure applied to the retainer ring through a polishing head may cause a portion of the polishing pad, adjacent to the edge of the wafer, to be deformed, so that a pad rebound phenomenon may occur. In addition, when performing a polishing process, slurry is used as an abrasive, and a phenomenon in which the slurry is pushed toward the edge of the wafer may occur, and in this case, when the slurry is not discharged smoothly, an edge fast phenomenon of a wafer polishing speed may occur. Furthermore, the slurry may adhere to the retainer ring and be fixed thereto, and the fixed slurry may cause defects such as scratch defects on the wafer during the polishing process.

SUMMARY

An aspect of the present inventive concept provides a retainer ring for a polishing head that can improve pressure distribution on a wafer.

An aspect of the present inventive concept provides a retainer ring for a polishing head that can prevent slurry fixation and scratch defects.

According to an aspect of the present inventive concept, a retainer ring for a polishing head may include: a ring-shaped body including a pressure surface having a plurality of first regions and a plurality of second regions alternately disposed in a circumferential direction of the body; a plurality of slurry grooves disposed in the pressure surface to be spaced apart from each other in the circumferential direction of the body and extending from an inner circumferential surface of the body to an outer circumferential surface of the body; and a plurality of rounded grooves disposed in the plurality of first regions and directly connected to the inner circumferential surface of the body, each of the plurality of rounded grooves having a concave groove surface rounded in a cross-sectional view taken along a radial direction of the body.

According to an aspect of the present inventive concept, a retainer ring for a polishing head may include: a ring-shaped body surrounding an accommodating space configured to accommodate a wafer and including a pressure surface having a plurality of first regions and a plurality of second regions alternately disposed in a circumferential direction of the body; a plurality of slurry grooves disposed in the pressure surface to be spaced apart from each other at equal intervals in the circumferential direction of the body and extending from an inner circumferential surface of the body to an outer circumferential surface of the body; and a plurality of rounded grooves disposed in the plurality of first regions of the pressure surface, each of the plurality of rounded grooves connected to at least one slurry groove among the plurality of slurry grooves, the plurality of rounded grooves each having a concave groove surface rounded in a cross-sectional view taken along a radial direction of the body; wherein the inner circumferential surface of the body and each of the plurality of second regions of the pressure surface are perpendicularly connected to each other.

According to an aspect of the present inventive concept, a retainer ring for a polishing head may include: a ring-shaped body including a pressure surface having a plurality of first regions and a plurality of second regions alternately disposed in a circumferential direction of the body; a plurality of slurry grooves disposed in the pressure surface to be spaced apart from each other in the circumferential direction of the body and extending from an inner circumferential surface of the body to an outer circumferential surface of the body; and a plurality of rounded grooves disposed in the plurality of first regions, the plurality of rounded grooves each having a concave groove surface rounded in a cross-sectional view taken along a radial direction of the body, wherein the plurality of rounded grooves include a plurality of first rounded grooves disposed in at least one first region among the plurality of first regions and a plurality of second rounded grooves disposed in at least another first region among the plurality of first regions and having at least one different shape and size from the plurality of first rounded grooves.

BRIEF DESCRIPTION OF DRAWINGS

The above and other aspects, features, and advantages of the present disclosure will be more clearly understood from the following detailed description, taken in conjunction with the accompanying drawings:

FIG. 1 is an exemplary diagram illustrating a polishing apparatus including a retainer ring for a polishing head according to an example embodiment of the present inventive concept;

FIG. 2 is an exemplary diagram illustrating that a pad rebound phenomenon occurs on a polishing pad corresponding to an edge of a wafer during a conventional polishing process of a wafer;

FIG. 3 is an exemplary diagram illustrating a retainer ring for a polishing head according to an example embodiment of the present inventive concept;

FIG. 4 is an exemplary diagram illustrating a portion of a retainer ring for a polishing head according to an example embodiment of the present inventive concept;

FIG. 5 is an exemplary diagram illustrating a flow rate of slurry and a state of a polishing pad when a polishing process of a wafer is performed using a polishing apparatus to which a retainer ring for a polishing head according to an example embodiment of the present inventive concept is applied; and

FIGS. 6 to 11 are exemplary diagrams illustrating retainer rings for polishing heads according to different example embodiments of the present inventive concept.

DETAILED DESCRIPTION

Throughout the disclosure, spatially relative terms, such as “beneath,” “below,” “lower,” “above,” “upper,” “vertical,” “horizontal” and the like, may be used herein for ease of description to describe positional relationships, such as illustrated in the figures. It will be understood that the spatially relative terms encompass different orientations of the device in addition to the orientation depicted in the figures.

It will be understood that when an element is referred to as being “connected” or “coupled” to or “on” another element, it can be directly connected or coupled to or on the other element or intervening elements may be present. In contrast, when an element is referred to as being “directly connected” or “directly coupled” to another element, or as “contacting” or “in contact with” another element, there are no intervening elements present at the point of contact. Other words used to describe the relationship between elements should be interpreted in a like fashion (e.g., “between” versus “directly between,” “adjacent” versus “directly adjacent,” etc.).

Hereinafter, preferred example embodiments of the present inventive concept will be described with reference to the attached drawings.

FIG. 1 is an exemplary diagram illustrating a polishing apparatus including a retainer ring for a polishing head according to an example embodiment of the present inventive concept.

A retainer ring 100 for a polishing head 40 according to an example embodiment may be applied to a polishing head of a polishing apparatus. The polishing apparatus may be a chemical mechanical polishing apparatus 10, and may include a platen 20, a polishing pad 30, a polishing head 40, a slurry supply unit 50, and a conditioning unit 60.

The platen 20 may be rotatably installed on a rotation axis (not shown), and an upper end portion thereof may have a circular plate shape. For example, a top surface of the platen 20 may be flat, smooth, and horizontal. The platen 20 may be rotated in a certain direction (e.g., in a circumferential direction of the platen 20). In addition, a polishing pad 30 may be installed on an upper surface of the platen 20.

The polishing pad 30 may be provided with a polishing layer (not shown) on an upper/top surface for polishing a wafer W.

The polishing head 40 may be disposed above the platen 20 and may contact the wafer W with the polishing pad 30 when a polishing process is performed. In addition, the polishing head 40 may be rotated in a certain direction. Accordingly, the wafer W mounted on the bottom surface of the polishing head 40 may contact the polishing pad 30 while being rotated. As described above, mechanical polishing may be performed while the wafer W is in contact with the polishing pad 30. Although only one polishing head 40 is illustrated in FIG. 1, a plurality of polishing heads may be provided to hold additional wafers so that a surface area of the polishing pad 30 can be used efficiently.

The slurry supply unit 50 may supply slurry S to the polishing pad 30. Accordingly, the slurry S supplied from the slurry supply unit 50 may be provided to the polishing head 40 (e.g., between the polishing pad 30 and the polishing head 40). When a chemical mechanical polishing process is performed, chemical mechanical polishing of the wafer W may be performed using the slurry S supplied from the slurry supply unit 50.

The conditioning unit 60 plays a role in conditioning a surface condition of the polishing pad 30. As an example, the conditioning unit 60 may polish a surface of the polishing pad 30 to maintain surface roughness of the polishing pad 30 at a constant/predetermined state. The conditioning unit 60 may polish the polishing pad 30 while the polishing head 40 polishes a wafer W, or may polish the polishing pad 30 while the polishing head 40 is in a rest mode without polishing a wafer W to restore or maintain the surface roughness of the polishing pad 30. To this end, the conditioning unit 60 may be provided with a disk 62 configured to contact with the polishing pad 30.

The polishing head 40 may grind the wafer W, and move the ground wafer W to an upper portion (e.g., on a top surface) of the polishing pad 30. The polishing head 40 may polish the wafer W by contacting the wafer W transferred to the upper portion (e.g., the top surface) of the polishing pad 30. The polishing head 40 may determine a degree of polishing of the wafer W by controlling frictional force between the wafer W and the polishing pad 30, by pressurizing the wafer W in contact with the polishing pad 30. The polishing head 40 may include a head body 42, a membrane 44, and a retainer ring 100.

The head body 42 may adjust a position of the wafer W. The head body 42 may receive power from the outside, and rotate around an axis, perpendicular to a polishing surface of the polishing pad 30. The ground wafer W that has been ground according to the rotation of the head body 42 may be polished while rotating in contact with the polishing pad 30.

The head body 42 may move the wafer W horizontally. Depending on the horizontal movement of the head body 42, the wafer W may be transferred to a polishing position, or removed from the polishing position. The head body 42 may move the wafer W in an up-and-down direction relative to the polishing pad 30.

The membrane 44 may be connected to (e.g., contact) the head body 42 and may form a pressure chamber (not shown) therein to apply pressure to the wafer W. Depending on pressure fluctuation of the pressure chamber formed by the membrane 44, the pressure applied to the wafer W may be adjusted. A plurality of pressure chambers may be formed inside the membrane 44, different pressures may be applied to the pressure chamber, and a portion of the wafer W corresponding to each pressure chamber may be locally pressurized depending on the pressure applied to each pressure chamber.

The retainer ring 100 according to an example embodiment of the present inventive concept may be connected to the head body 42 to surround around the circumference of the wafer W. The retainer ring 100 can prevent the wafer W from being removed (e.g., slipped out) from the grinding position by rotational force of the polishing head 40. The retainer ring 100 may support the outer circumferential surface of the wafer W, thereby preventing the wafer W from being detached from the polishing head 40 due to vibrations occurring during the process of polishing the wafer W. The retainer ring 100 may be directly connected to the head body 42 or indirectly connected to the head body 42 through a separate connection member.

FIG. 2 is an exemplary diagram illustrating that a pad rebound phenomenon occurs on a polishing pad corresponding to an edge of a wafer during a conventional process of polishing a wafer.

As illustrated in FIG. 2, in a process of polishing a wafer W, a portion 32 of the polishing pad 30, adjacent to an edge E of the wafer W may be deformed by pressure applied to a retainer ring 70 through the head body 42, causing a pad rebound phenomenon. In addition, in the process of polishing a wafer W, a phenomenon in which slurry S used as an abrasive is pushed toward the edge E of the wafer W may occur by centrifugal force caused by the rotations of the polishing pad 30 and the polishing head 40. In this case, when the slurry S is not discharged smoothly, an edge fast phenomenon of a wafer polishing speed may occur.

To solve these problems, a retainer ring for a polishing head according to various example embodiments of the present inventive concept is provided with reference to the drawings below.

Example 1

FIG. 3 is an exemplary diagram illustrating a retainer ring for a polishing head according to an example embodiment of the present inventive concept, FIG. 4 is an exemplary diagram illustrating a portion of a retainer ring for a polishing head according to an example embodiment (Example 1) of the present inventive concept, and FIG. 5 is an exemplary diagram illustrating a flow state of slurry and a state of a polishing pad when a polishing process of a wafer is performed using a polishing apparatus to which a retainer ring for a polishing head according to an example embodiment (Example 1) of the present inventive concept is applied.

Referring to FIGS. 3 to 5, a retainer ring 100 according to an example embodiment (Example 1) of the present inventive concept may include a ring-shaped body 110, a plurality of slurry grooves 120, and a plurality of rounded grooves 130.

The body 110 may be formed in a ring shape. The body 110 may include a pressure surface 112 applying pressure toward the polishing pad 30. For example, the pressure surface 112 may be a surface of the body 110 facing the policing pad 30 while a chemical mechanical polishing process is performed. The pressure surface 112 may have a plurality of first regions A1 and a plurality of second regions A2 alternately disposed in a circumferential direction of the body 110. The first regions A1 and the second regions A2 may be distinguished/separated by a plurality of slurry grooves 120 formed in the pressure surface 112 of the body 110. For example, each of the plurality slurry grooves 120 may be placed between one of the first regions A1 and one of the second regions A2 directly adjacent to each other as shown in FIG. 3. Each of the plurality of first regions A1 of the pressure surface 112 of the body 110 may have the same area as each of the plurality of second regions A2. However, in other example embodiments, each of the plurality of first regions A1 of the pressure surface 112 of the body 110 may have a different area from each of the second regions A2, which will be described later. The body 110 may include a coupling surface 118 connected to the head body 42 of the polishing head 40. For example, the coupling surface 118 may be an opposite surface to the pressure surface 112 of the body 110. The body 110 may include an inner circumferential surface (e.g., an inner surface) 114 facing the edge E of the wafer W (e.g., while a planarizing process is performed on the wafer W) and an outer circumferential surface (e.g., an outer surface) 116 opposite to the inner circumferential surface 114. An accommodating space S1 for accommodating the wafer W may be formed on an inner side of the inner circumferential surface 114 of the body 110. For example, the pressure surface 112 may be a surface disposed between the inner circumferential surface 114 and the outer circumferential surface 116 of the body 110.

A plurality of slurry grooves 120 may be disposed in the pressure surface 112 to be spaced apart from each other in the circumferential direction of the body 110 in/between the first regions A1 and the second regions A2 of the pressure surface 112 of the body 110. The plurality of slurry grooves 120 may extend from the inner circumferential surface 114 of the body 110 to the outer circumferential surface 116 of the body 110. In an example embodiment, the slurry grooves 120 may be formed in a form which is inclined at a certain angle in one direction in the circumferential direction of the body 110. For example, each of the slurry grooves 120 may extend lengthwise in a direction having a certain angle to the inner circumferential surface 114 in a plan view. For example, the angles formed between the inner circumferential surface 114 and the respective lengthwise directions of the slurry grooves 120 in the plan view may be the same. For example, each of the angles formed between the inner circumferential surface 114 and the respective lengthwise directions of the slurry grooves 120 in the plan view may not be a right angle. For example, the slurry grooves 120 may be inclined (which is neither parallel nor perpendicular) with respect to radial directions of the body 110 and with respective to circumferential directions of the body 110 at respective positions at which the slurry grooves 120 are positioned. However, the inventive concept is not limited thereto, and the slurry grooves 120 may be formed in various forms/angles as needed.

The plurality of rounded grooves 130 may be disposed in the plurality of first regions A1 of the pressure surface 112 of the body 110. As illustrated in FIGS. 3 and 4, the plurality of rounded grooves 130 may be disposed in the plurality of first regions A1 of the pressure surface 112 of the body 110. Each of the plurality of rounded grooves 130 may be disposed in a connection portion between the inner circumferential surface 114 of the body 110 and the pressure surface 112, and may have a concave groove surface 132 rounded/curved in/along a radial direction of the body 110. For example, the concave groove surface of each of the rounded grooves 130 may be rounded/curved in a cross-sectional view taken along a plane extending in a radial direction of the body 110 and extending in a vertical direction which is perpendicular to the radial direction of the body 110 and perpendicular to a flat portion of the pressure surface 112 of the body 110. For example, the pressure surface 112 may include the plurality of rounded grooves 130 formed in the first regions A1 of the pressure surface 112 and the rounded grooves 130 may be directly connected to the inner circumferential surface 114 of the body 110. For example, the rounded grooves 130 may be grooves extending in the circumferential direction of the body 110 along an inner surface of the body 110. Sizes (e.g., areas/lengths/widths) of the rounded grooves 130 may be variously set depending on the process, and a degree of pressure control for the wafer W and the polishing pad 30 may vary depending on the sizes of the rounded grooves 130. Through the structure of the plurality rounded grooves 130, by reducing contact pressure between the retainer ring 100 and the polishing pad 30, a rebound phenomenon of the polishing pad 30 may be prevented, and also, by reducing a contact area between the edge E of the wafer W and the retainer ring 100 by force caused by the rotation of the polishing head 40 and frictional force of the polishing pad 30, the occurrence of scratches caused by collisions between the edge E of the wafer W and the retainer ring 100 may be effectively prevented. In addition, by disposing the plurality of rounded grooves 130 in the first regions A1 and not disposing rounded grooves in the second regions A2 while the first regions A1 and the second regions A2 are alternately disposed on the pressure surface 112 of the body 110, it can prevent the wafer W from being caught/jammed in the rounded grooves 130 due to the wafer W being titled to one side of the retainer ring 100 or moved under the rounded grooves 130, so that a polishing process may be performed while the wafer W maintains a correct position thereof. Furthermore, the plurality of rounded grooves 130 may prevent a sudden collision between the retainer ring 100 and the slurry S moving toward and/or passing by the edge E of the wafer W by centrifugal force through a shape having a rounded concave groove surface 132, and prevent slurry fixation and scratch defects by implementing smooth discharge into/through the slurry grooves 120, and thus effectively prevent an edge fast phenomenon of the polishing speed of the wafer W. For example, the slurry fixation may be a state that the slurry S is attached on or near the retainer ring 100, and the scratch defects may be caused by particles of slurry agglomerates or by collisions between the edge E of the wafer W and the retainer ring 100.

The plurality of rounded grooves 130 may have various shapes, sizes, and the like such that some rounded grooves 130 are different from other rounded grooves 130. In an example embodiment, at least one rounded groove 130 may be disposed in each of the plurality of first regions A1. As shown in FIG. 3 in an example embodiment, one rounded groove 130 may be disposed in each of the plurality of first regions A1. Each of the plurality of rounded grooves 130 may be disposed in a connection portion between the inner circumferential surface 114 of the body 110 and the pressure surface 112 in the first region A1 of the pressure surface 112 of the body 110 and extend in the circumferential direction of the body 110. For example, the connection portion between the inner circumferential surface 114 of the body 110 and the pressure surface 112 may be an edge portion of the pressure surface 112 in which the pressure surface 112 including the rounded grooves 130 is connected to the inner circumferential surface 114 of the body 110. Each of the plurality of rounded grooves 130 may be connected to at least one of the plurality of slurry grooves 120. As shown in FIGS. 3 and 4 in an example embodiment, both/opposite ends of each of the plurality of rounded grooves 130 may be respectively connected to two adjacent slurry grooves 120 among the plurality of slurry grooves. Through the plurality of rounded grooves 130 and the plurality of slurry grooves 120, the slurry S can be rapidly and smoothly discharged externally.

The rounded grooves 130 disposed in the plurality of first regions A1 of the pressure surface 112 may be formed to have the same shape. For example, as shown in FIGS. 3 to 5, each of the plurality of rounded grooves 130 may be formed in an arc shape in which the concave groove surface 132 has the same size/length in a circumferential direction of the body 110. When each of the above plurality of rounded grooves 130 is formed in an arc shape having the same size/shape in the circumferential direction of the body 110 in the concave groove surface 132, a radius of the concave groove surface 132 may be 1 mm to 5 mm. For example, the radius of the concave groove surface 132 may be measured with respect to an arc of the concave groove surface 132 in a cross-sectional view taken along a plane extending in a radial direction of the body 110 and in a vertical direction which is perpendicular to the radial direction of the body 110 and perpendicular to a flat portion of the pressure surface 112 of the body 110. The flat portion of the pressure surface 132 may be a portion contacting the polishing pad 30 during a polishing process of a wafer W. For example, the radius of the concave groove surface 132 may be 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, or a value therebetween, but the present inventive concept is not limited thereto, and may be formed in various sizes and shapes, such as having a width of 5 mm or more, e.g., in a radial direction of the body 110, depending on actual needs. In the present inventive concept, the rounded groove is not limited to the arc shape (e.g., a shape of an arc of a circle), and may be formed to have various shapes, such as an elliptical arc shape (a shape of an arc of an ellipse) or a combination of a straight line shape and a round shape (e.g., a combination of a flat surface and a curved surface), as long as it has a shape that forms a rounded concave groove surface, which will be described later. For example, arc shapes and straight line shapes of surfaces in the present disclosure may be shapes shown in cross-sectional views of the corresponding surfaces.

A depth of each of the plurality of rounded grooves 130 may be appropriately set. In an example embodiment, the depth of each of the plurality of rounded grooves 130 may be disposed on the same level as the depth of the slurry grooves 120 at most. In an example embodiment, as shown in FIGS. 3 to 5, the plurality of rounded grooves 130 may be configured such that depths of the grooves of the plurality of rounded grooves 130 may be the same as the depth of the slurry grooves 120. Accordingly, in the polishing process of the wafer W, the slurry S may be guided to flow smoothly into the slurry grooves 120 through the rounded grooves 130. However, in the present inventive concept, the rounded grooves 130 are not limited to this structure, and the depths of the grooves of the plurality of rounded grooves 130 may be smaller than the depths of the slurry grooves 130, if necessary. The depths of the rounded grooves 130 and the depths of the slurry grooves 130 may be vertical distances from a level of a flat surface portion of the pressure surface 112 extending in a horizontal direction. The flat surface portion of the pressure surface 112 may be a portion contacting the polishing pad 30 during a polishing process of a wafer W.

Referring to FIG. 3, the retainer ring 100 may include a plurality of vertical connection portions C disposed in the plurality of second regions A2. In the plurality of vertical connection portions C, the inner circumferential surface 114 of the body 110 extending in a vertical direction and the pressure surface 112 extending in a horizontal direction may be perpendicularly connected to each other in the plurality of second regions A2 of the pressure surface 112. For example, the inner circumferential surface 114 may be perpendicular to the pressure surface 112 in a cross-sectional view taken along a plane extending in a vertical direction and in a radial direction of the body 110. The plurality of rounded grooves 130 may be disposed in the first regions A1 to be spaced apart from each other at equal intervals with the vertical connection portions C interposed therebetween. In an example embodiment, the number of the rounded grooves 130 disposed in each of the plurality of first regions A1 may be the same as the number of the vertical connection portions C located in each of the second regions A2. By alternately disposing the rounded grooves 130 and the vertical connection portions C, a phenomenon of the wafer being caught/jammed in the rounded grooves 130 can be effectively prevented.

In Example 1 above, it is illustrated that a concave groove surface of the rounded groove has an arc shape curved along the circumferential direction of the body 110, and the plurality of rounded grooves have the same size/length in the circumferential direction of the body 110, but the present inventive concept is not limited thereto, and may be formed in various sizes and shapes according to actual needs. Hereinafter, a description is given with reference to Example 2 in which the concave groove surface of the rounded groove is formed in an elliptical arc shape.

Example 2

FIG. 6 is an exemplary diagram of a retainer ring for a polishing head according to an example embodiment (Example 2) of the present inventive concept.

Referring to FIG. 6, a retainer ring 200 according to an example embodiment (Example 2) of the present inventive concept may include a ring-shaped body 210, a plurality of slurry grooves 220, a plurality of rounded grooves 230, and a plurality of vertical connection portions C. The configuration of the body 210, the slurry grooves 220, and the vertical connection portions C may be implemented in the same manner as the body 110, the slurry grooves 120, and the vertical connection portions C in Example 1 above, and a duplicate description thereof is omitted.

Each of the plurality of rounded grooves 230 may be disposed in a connection portion between an inner circumferential surface 214 of the body 210 and a pressure surface 212 in the first region A1 of the pressure surface 212 of the body 210 and may extend in a circumferential direction of the body 210. For example, the connection portion between an inner circumferential surface 214 of the body 210 and a pressure surface 212 may be an edge portion of the pressure surface 212 in which a rounded groove 230 is formed. The rounded groove 230 which is included in the pressure surface 212 may be directly connected to the inner circumferential surface 214 of the body 210. Each of the plurality of rounded grooves 230 may be connected to two adjacent slurry grooves 220. The rounded grooves 230 disposed in the plurality of first regions A1 of the pressure surface 212 may be formed to have the same shape. Each of the plurality of rounded grooves 230 may be formed in an elliptical arc shape, e.g., in a cross-sectional view taken along a radial direction of the body 210, having a concave groove surface 232 having the same radius/curvature in the circumferential direction of the body 210, e.g., throughout the concave groove surface 232 from one end to the other end of the concave groove surface 232 in the circumferential direction of the body 210.

In the plurality of vertical connection portions C, the inner circumferential surface 214 of the body 210 and the pressure surface 212 may be perpendicularly connected to each other in the plurality of second regions A2 of the pressure surface 212. For example, the inner circumferential surface 214 of the body 210 and the pressure surface 212 may be perpendicular to each other in a cross-sectional view taken along a plane extending in a radial direction of the body 210 and extending in a vertical direction. The plurality of rounded grooves 230 may be disposed in the first regions A1 to be spaced apart from each other at equal intervals in the pressure surface 212 with the vertical connection portions C interposed therebetween. By alternately disposing the rounded grooves 230 and the vertical connection portions C, a phenomenon in which the wafer is caught/jammed/stuck in the rounded grooves 230 may be effectively prevented.

In Example 2 above, it is described that the concave groove surface of the rounded groove is formed to have an elliptical arc shape, but the present inventive concept is not limited thereto and may be formed to have various sizes and shapes according to actual needs. Hereinafter, a description is given with reference to Example 3 in which the concave groove surface of the rounded groove is formed as a combination of a straight line shape and a rounded shape.

Example 3

FIG. 7 is an exemplary diagram of a retainer ring for a polishing head according to an example embodiment (Example 3) of the present inventive concept.

Referring to FIG. 7, a retainer ring 300 according to an example embodiment (Example 3) of the present inventive concept may include a ring-shaped body 310, a plurality of slurry grooves 320, a plurality of rounded grooves 330, and a plurality of vertical connection portions C. The configuration of the body 310, the slurry grooves 320, and the vertical connection portions C may be implemented in the same manner as the body 110, the slurry grooves 120, and the vertical connection portions C in Example 1 above, and a duplicate description thereof is omitted.

Each of the plurality of rounded grooves 330 may be disposed in a connection portion between an inner circumferential surface 314 of the body 310 and the pressure surface 312 in the first region A1 of the pressure surface 312 of the body 310 and may extend in a circumferential direction of the body 310. For example, the connection portion between an inner circumferential surface 314 of the body 310 and a pressure surface 312 may be an edge portion of the pressure surface 312 in which a rounded groove 330 is formed. The rounded groove 330 which is formed in a first region A1 of the pressure surface 312 may be directly connected to the inner circumferential surface 314 of the body 310. Each of the plurality of rounded grooves 330 may be connected to two adjacent slurry grooves 320. The plurality of rounded grooves 330 disposed in the plurality of first regions A1 of the pressure surface 312 may be formed to have the same shape.

The concave groove surface 332 of each of the plurality of rounded grooves 330 may include a straight line portion 334 connected to and/or contacting/meeting the inner circumferential surface 314 of the body 310 and a curved line portion 336 connecting and disposed between the straight line portion 334 and the other portion of the pressure surface 312 of the body 310, when viewed in a cross-sectional view of the body 310 taken along a plane extending in a vertical direction and in a radial direction of the body 310. For example, the concave groove surface 332 of each of the plurality of rounded grooves 330 may include a flat surface having a straight side/edge 334 and connected to (contacting/meeting) the inner circumferential surface 314 of the body 310 and a curved surface having a curved edge 336 and connecting and/or disposed between the flat surface and the rest portion of the pressure surface 312 of the body 310.

Both/opposite ends of each of the plurality of rounded grooves 330 may be respectively connected to two adjacent slurry grooves 320. As shown in FIG. 7, each of the plurality of rounded grooves 330 may extend in a radial direction of the body 310 and may have an asymmetrical structure with respect to an imaginary center line L passing through a central portion of each of the rounded grooves 330 in a radial direction. In an example embodiment, each of the plurality of rounded grooves 330 may be formed in a shape in which a width of the concave groove surface 332 gradually increases in one direction (a rotational direction of the polishing head) in the circumferential direction of the body 310. For example, each rounded groove 330 may have a width increasing in a direction moving along a circumferential direction of the body 310. For example, the widths of the rounded grooves 330 may be distances between opposite ends of the rounded grooves 330 in a radial direction of the body 310, e.g., in a plan view.

The concave groove surface at a first end 331 of each of the plurality of rounded grooves 330 may include a first straight line portion 334a connected to (contacting/meeting) the inner circumferential surface 314 of the body 310 and a first curved line portion 336a connecting the first straight line portion 334a and the other portion of the pressure surface 312 of the body 310. The concave groove surface at a second end 333, opposite to the first end 331 of each of the plurality of rounded grooves 330 may include a second straight line portion 334b connected to (contacting/meeting) the inner circumferential surface 314 of the body 310 and a second curved line portion 336b connecting the second straight line portion 334b and the other portion of the pressure surface 312 of the body 310. Each of the plurality of rounded grooves 330 may have a concave groove surface 332 of which a width gradually increases in a direction receding from the first end 331 and approaching the second end 333. The width of the second end 333 of each of the plurality of rounded grooves 330 may be configured to a maximum extension length of the slurry groove 320. A width of the first straight line portion 334a of the concave groove surface at the first end 331 of each of the plurality of rounded grooves 330 may be smaller than a width of the second straight line portion 334b of the concave groove surface of the second end 333 of each of the plurality of rounded grooves 330. A width of the first curved line portion 336a of the concave groove surface of the first end 331 of each of the plurality of rounded grooves 330 may be the same as or different from a width of the second curved line portion 336b of the concave groove surface of the second end 333 of each of the plurality of rounded grooves 330. For example, widths of the rounded grooves and widths of surfaces of the rounded grooves in the present disclosure may be distances between opposite ends of the rounded grooves and surfaces of the rounded grooves in radial directions of the corresponding ring body.

In the present embodiment, it is described that the plurality of rounded grooves 330 has an asymmetrical structure, but the present inventive concept is not limited thereto. As another example, the plurality of rounded grooves may have the same width throughout each rounded groove in the circumferential direction of the body. The widths of the first straight line portion and the first curved line portion of the first end of each of the plurality of rounded grooves and the widths of the second straight line portion and the second curved line portion of the second end of each of the plurality of rounded grooves may be the same.

In Examples 1 to 3 above, it is described that areas of the first regions A1 and the second regions A2 in the respective pressure surfaces 112, 212, and 312 of the bodies 110, 210, and 310 are the same, but the present inventive concept is not limited thereto, and the areas of a first region A1 and a second region A2 of the pressure surfaces of the bodies may be different from each other, which will be described below with reference to Examples 4 and 5.

Example 4

FIG. 8 is an exemplary diagram of a retainer ring for a polishing head according to an example embodiment (Example 4) of the present inventive concept.

Referring to FIG. 8, a retainer ring 400 according to an example embodiment (Example 4) of the present inventive concept may include a ring-shaped body 410, a plurality of slurry grooves 420, a plurality of rounded grooves 430, and a plurality of vertical connection portions C. The configuration of the slurry grooves 420 may be implemented in the same manner as the slurry grooves 120 in Example 1 above, and a duplicate description thereof is omitted.

Each of the plurality of first regions A1 of the pressure surface 412 of the body 410 may have a different area from each of the second regions A2. Each of the plurality of first regions A1 of the pressure surface 412 may have a larger area than each of the second regions A2. A plurality of rounded grooves 430 may be disposed in each of the plurality of first regions A1. As an example embodiment, FIG. 8 illustrates a form in which two rounded grooves 430 are disposed in each of the plurality of first regions A1, but the present inventive concept is not limited thereto, and three or more rounded grooves may be positioned in each of the plurality of first regions A1. The number of the rounded grooves 430 disposed in each of the plurality of first regions A1 may be greater than the number of the vertical connection portions C disposed in each of the second regions A2. However, as another example, the number of the rounded grooves disposed in each of the plurality of first regions may be the same as the number of the vertical connection portions C disposed in each of the plurality of second regions. In addition, FIG. 8 illustrates that the rounded grooves 430 have the same shape as the rounded grooves 130 of Example 1 above, but the present inventive concept is not limited thereto, and the rounded grooves 430 may be implemented in the shape of the rounded grooves 230 and/or 330 described in the Examples 2 and 3 above or in other shapes.

Although it is described that a plurality of rounded grooves are disposed in each of the plurality of first regions, one rounded groove extending integrally in the circumferential direction of the body may also be disposed in each of the plurality of first regions. In this case, the rounded groove may be connected to two or three or more slurry grooves.

Example 5

FIG. 9 is an exemplary diagram of a retainer ring for a polishing head according to an example embodiment (Example 5) of the present inventive concept.

Referring to FIG. 9, a retainer ring 500 according to an example embodiment (Example 5) of the present inventive concept may include a ring-shaped body 510, a plurality of slurry grooves 520, a plurality of rounded grooves 530, and a plurality of vertical connection portions C. The configuration of the slurry grooves 520 may be implemented in the same manner as the slurry grooves 120 in Example 1 above, except that the number of slurry grooves 120 is set to be larger than that in Example 1 above, and a duplicate description thereof is omitted.

Each of the plurality of first regions A1 of a pressure surface 512 of the body 510 may have a different area/size from each of the second regions A2. Each of the plurality of first regions A1 of the pressure surface 512 may have a larger area than each of the second regions A2. A plurality of the rounded grooves 530 may be disposed in each of the plurality of first regions A1. In an example embodiment illustrated in FIG. 9, eight rounded grooves 530 are disposed in each of the plurality of first regions A1, but the present inventive concept is not limited thereto, and one or two or more rounded grooves may be disposed in each of the plurality of first regions A1. The number of the rounded grooves 530 disposed in each of the plurality of first regions A1 may be greater than the number of the vertical connection portions C disposed in each of the plurality of second regions A2. However, as another example, the number of the rounded grooves disposed in each of the plurality of first regions A1 may be the same as the number of the vertical connection portions C disposed in each of the plurality of second regions A2.

Rounded grooves having different shapes from each other may be disposed in at least two first regions A1 among the plurality of first regions A1. In an example embodiment, one rounded groove disposed in one first region A1 among the plurality of first regions A1 of the pressure surface 512 of the body 510 and another rounded groove disposed in another first region A1 among the plurality of first regions A1 may be formed to have different shapes from each other. In an example embodiment as shown in FIG. 9, the plurality of rounded grooves 530 may include a plurality of first rounded grooves 530a disposed in at least one first region A11 among the plurality of first regions A1 and a plurality of second rounded grooves 530b disposed in at least another first region A12 among the plurality of first regions A1. The plurality of first rounded grooves 530a and the plurality of second rounded grooves 530b may have at least one different shape and/or size from other rounded grooves. In an example embodiment, as shown in FIG. 9, the first rounded grooves 530a may be configured/formed in the same manner (e.g., the same shape and/or size) as the rounded grooves 130 described in Example 1 above, and the second rounded grooves 530b may be configured/formed in the same manner (e.g., the same shape and/or size) as the rounded grooves 230 described in Example 2 above. Rounded grooves 530a, 530b, and 530c of different shapes may be respectively disposed in the plurality of first regions A11, A12, and A13, and accordingly, a polishing rate for the wafer can be controlled. In FIG. 9, a third rounded groove 530c having a different shape or size from the plurality of first rounded grooves 530a and the plurality of second rounded grooves 530b may be disposed in a first region A13, other than the first regions A11 and A12 in which the plurality of first rounded grooves 530a and the plurality of second rounded grooves 530b are respectively disposed. In an example embodiment, as illustrated in FIG. 9, the third rounded groove 530c may be configured/formed in the same manner (e.g., the same shape and/or size) as the rounded groove 330 described in Example 3 above, but the present inventive concept is not limited thereto.

By disposing at least two rounded grooves 530 having different shapes and/or sizes in each of the plurality of first regions A1 of the pressure surface 512 of the body 510, a pressure distribution effect of the wafer can be improved.

In Examples 1 to 5 above, it is described that the slurry grooves 120, 220, 320, 420, and 520 are formed to be inclined at a certain angle in one direction in the circumferential direction of the body, but the present inventive concept not limited thereto. Depending on need, the slurry groove may be implemented in various forms, which are described below with reference to Example 6.

Example 6

FIG. 10 is an exemplary diagram of a retainer ring for a polishing head according to an example embodiment (Example 6) of the present inventive concept.

Referring to FIG. 10, a retainer ring 600 according to an example embodiment (Example 6) of the present inventive concept may include a ring-shaped body 610, a plurality of slurry grooves 620, a plurality of rounded grooves 630, and a plurality of vertical connection portions C. The configuration of the ring-shaped body 610, the rounded grooves 630, and the vertical connection portions C may be implemented in the same manner as the configuration of the slurry grooves 120, the rounded grooves 130, and the vertical connection portions C in Example 1 above, and a duplicate description thereof is omitted. In certain embodiments, regarding the configuration of the body 610, the rounded grooves 630, and the vertical connection portions C, the configuration of the bodies 210, 310, 410, and 510, the rounded grooves 230, 330, 430, and 530, and the vertical connection portions C of Examples 2 to 5 may be applied instead of the configuration of Example 1.

A plurality of slurry grooves 620 may be disposed in the pressure surface 612 to be spaced apart in the circumferential direction of the body 610 between first regions A1 and second regions A2 of the pressure surface 612 of the body 610. For example, the first regions A1 and the second regions A2 are arranged alternately along a circumferential direction of the body 610, and the slurry grooves 620 may be disposed at boundaries between the first regions A1 and the second regions A2 as shown in FIG. 10. The plurality of slurry grooves 620 may extend from the inner circumferential surface 614 of the body 610 to the outer circumferential surface 616 of the body 610. In an example embodiment, the slurry grooves 620 may be formed in a shape that is curved in one direction (rotational direction) in the circumferential direction of the body 610. For example, the slurry grooves 620 may be curved in a plan view. Accordingly, through the slurry grooves 620 formed in a curved shape in the same direction as the rotational direction of the polishing head, smooth discharge of slurry can be implemented/accomplished during the polishing process of the wafer, thereby preventing slurry fixation and scratch defects, and effectively preventing an edge fast phenomenon of the polishing speed of the wafer W.

As shown in FIGS. 3 to 10 in Examples 1 to 6, it is illustrated that the retainer rings 100, 200, 300, 400, 500, and 600 include a body integrally formed in a radial direction of the body, but the present inventive concept is not limited thereto, and it may be also be implemented to have a body having a separated form in the radial direction of the above body, which is described with reference to Example 7 below.

Example 7

FIG. 11 is an exemplary diagram of a retainer ring for a polishing head according to an example embodiment 7 of the present inventive concept.

Referring to FIG. 11, a retainer ring 700 according to an example embodiment (Example 7) of the present inventive concept may include a ring-shaped body 710, a plurality of slurry grooves 720, a plurality of rounded grooves 730, and a plurality of vertical connection portions C. The configuration of the slurry grooves 720, the rounded grooves 730, and the vertical connection portions C may be implemented in the same manner as the configuration of the slurry grooves 120, the rounded grooves 130, and the vertical connection portions C in Example 1 above, and a duplicate description thereof is omitted. In certain embodiments, regarding the configuration of the slurry grooves 720, the rounded grooves 730, and the vertical connection portions C, the configuration of the slurry grooves, the rounded grooves, and the vertical connection portions C in Examples 2 to 6 may be applied, instead of the configuration of Example 1.

The body 710 may include an inner ring body 710a and an outer ring body 710b disposed to surround an outer side/surface of the inner ring body 710a. The inner ring body 710a may surround an accommodating space S1 for accommodating a wafer W and may include a first inner circumferential surface 714a configured to face the wafer placed in the accommodating space S1 and an first outer circumferential surface 716a facing a second inner circumferential surface 714b of the outer ring body 710b. The outer ring body 710b may include a second inner circumferential surface 714b facing the first outer circumferential surface 716a and a second outer circumferential surface 716b opposite to the second inner circumferential surface 714b. The inner ring body 710a and the outer ring body 710b may collectively form a pressure surface 712 applying pressure on/toward the polishing pad. The inner ring body 710a and the outer ring body 710b may form a pressure surface 712 which is disposed at the same level throughout the pressure surface 712. The plurality of slurry grooves 720 may be disposed in the first regions A1 to be spaced apart in the circumferential direction of the body 710 across the entire pressure surface 712 of the inner ring body 710a and the outer ring body 710b. For example, the slurry grooves 720 may be formed in the pressure surface 712, and the pressure surface 712 may include the plurality of slurry grooves 720. The first regions A1 and the second regions A2 may be distinguished/separated by a plurality of slurry grooves 720 formed therebetween in the pressure surface 712 of the body 710. The plurality of rounded grooves 730 may be disposed in the plurality of first regions A1, and each of the rounded grooves 730 may be disposed in a connection portion between the first inner circumferential surface 714a of the inner ring body 710a and the pressure surface 712 of the ring body 710. For example, the connection portion between the first inner circumferential surface 714a of the inner ring body 710a and the pressure surface 712 may be an inner edge portion of the pressure surface 712 in which a rounded groove 730 is formed. The rounded groove 730 which is included in the pressure surface 712 may be directly connected to the first inner circumferential surface 714a of the inner ring body 710a. In FIG. 11, it is illustrated that there is a gap between the inner ring body 710a and the outer ring body 710b, but the present inventive concept is not limited to the form, and the inner ring body 710a and the outer ring body 710b may be disposed to be in contact with each other.

Through a dual ring structure including the inner ring body 710a and the outer ring body 710b, pressure distribution on an edge of the wafer may be controlled and improved, and a pad rebound phenomenon may be effectively prevented.

According to the configuration of the retainer ring for a polishing head according to the above-described embodiments, a retainer ring for a polishing head that can improve pressure distribution on the wafer may be provided, and in addition, slurry fixation and scratch defects may be prevented.

In the above-described embodiments, the shape, size, number, dispositional ratio of the slurry grooves or rounded grooves, and the vertical connection portions may vary depending on the actual process.

As set forth above, according to the present inventive concept, a retainer ring for a polishing head that can improve pressure distribution on a wafer may be provided.

In addition, in the present inventive concept, a retainer ring for a polishing head that can prevent slurry fixation and scratch defects may be provided.

Even though different figures illustrate variations of exemplary embodiments and different embodiments disclose different features from each other, these figures and embodiments are not necessarily intended to be mutually exclusive from each other. Rather, features depicted in different figures and/or described above in different embodiments can be combined with other features from other figures/embodiments to result in additional variations of embodiments, when taking the figures and related descriptions of embodiments as a whole into consideration. For example, components and/or features of different embodiments described above can be combined with components and/or features of other embodiments interchangeably or additionally to form additional embodiments unless the context clearly indicates otherwise, and the present disclosure includes the additional embodiments.

Various advantages and effects of the present inventive concept are not limited to the above description, and may be easily understood by those skilled in the art of the present disclosure.

While example embodiments have been shown and described above, it will be apparent to those skilled in the art that modifications and variations could be made without departing from the scope of the present inventive concept as defined by the appended claims.