Retaining ring

Abstract

A retaining ring according to an embodiment of the present invention may comprise: an inner ring; an outer ring formed to surround at least a portion of the inner ring and made of a material different from that of the inner ring; and a support block which is inserted into the inner ring and the outer ring, and which has a contact protrusion protruding from the lower end thereof so as to be in contact with the end of the ejector pin of the mold.

Description

Technical Field

[0001] The present invention relates to a retaining ring, and more particularly, to a retaining ring used on a polishing head of a CMP device to accommodate a semiconductor wafer in a predetermined area during a CMP (chemical mechanical polishing) process. Background Art

[0002] Recently, as semiconductor wafers have become denser and more functional, chemical mechanical polishing (CMP) apparatuses are being used as apparatuses for planarizing the surfaces of semiconductor wafers, and perform mechanical polishing simultaneously with chemical polishing.

[0003] In the semiconductor manufacturing process, the CMP process uses a chemical liquid slurry and a polishing pad to transmit the mechanical force of the polishing pad to the wafer while a chemical reaction occurs between the slurry and the wafer, thereby flattening the wafer.

[0004] In a CMP apparatus, a polishing head includes a holding ring and a wafer carrier. The wafer carrier plays a role in placing the wafer on the polishing pad in a state of contact with the bottom of the polishing head, and then the polishing pad and the polishing head rotate to rotate the wafer while polishing.

[0005] During the grinding process of the wafer, the retaining ring disposed at the lower end of the wafer carrier plays a role in preventing the wafer from detaching from the wafer carrier during the grinding process of the wafer. The retaining ring is usually located at the lower end of the wafer carrier and is a ring shape surrounding the side of the wafer.

[0006] As described above, the retaining ring used in the CMP process has become an inevitable requirement for high mechanical strength and chemical resistance. In the past, the retaining ring was usually manufactured by injection molding using engineering plastics with excellent mechanical strength and chemical resistance, or by insert injection molding in which a metal core is inserted into the engineering plastics for injection molding. In the manufacturing process of such retaining rings, the problem of unilateral wear on the surface of the retaining ring occurs, and therefore, it is necessary to develop a retaining ring that can improve this problem. Summary of the invention

[0007] (Problem to be solved)

[0008] An embodiment of the present invention provides a retaining ring that is manufactured to keep the retaining ring flat without left-right distortion, thereby preventing single-sided grinding during the grinding process.

[0009] The problems to be solved by the present invention are not limited to those mentioned above, and other problems not mentioned here can be clearly understood from the following description by relevant persons having ordinary knowledge in the technical field to which the present invention belongs.

[0010] (Methods to solve the problem)

[0011] According to an embodiment of the present invention, a retaining ring may include: an inner ring; an outer ring formed to surround at least a portion of the inner ring and made of a material different from that of the inner ring; and a support block inserted into the inner ring and the outer ring and having a protruding contact protrusion at the lower end to contact the end of the ejector pin of the mold.

[0012] A coupling groove for coupling with the grinding head is formed on the upper surface of the outer ring, and a module groove corresponding to the coupling groove can be formed by being recessed on the upper surface of the support block.

[0013] The support block may be formed at a position corresponding to a slurry discharge groove formed along a circumferential direction below the outer ring.

[0014] The contact protrusion is a part of which is cut off from the upper end by machining during the manufacturing process, and can be exposed to the outside in the slurry discharge groove.

[0015] A blocking flange may be arranged on the outer peripheral surface of the support block, and the blocking flange protrudes radially to block the slurry and prevent the slurry from flowing toward the inner ring side.

[0016] A recessed portion may be formed in an outer circumferential surface of the support block at an upper side of the stopper flange, the recessed portion being recessed to have a smaller diameter than the stopper flange.

[0017] An inclined surface that is radially inclined upward may be formed on the outer peripheral surface of the support block.

[0018] The two or more inclined surfaces may have mutually different inclination angles.

[0019] The inner ring can be made of metal material, and the outer ring and the support block can be made of resin material.

[0020] (Effects of the Invention)

[0021] According to one embodiment of the present invention, a contact protrusion is protruded from the lower end of the support block to contact the end of the upper ejector pin of the mold, and the support block is manufactured while maintaining flatness, horizontality, and concentricity without distortion. Therefore, the retaining ring is manufactured to be flat without left-right distortion, thereby preventing one-sided grinding during the grinding process. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 1 is a perspective view showing an upper portion of a retaining ring according to an embodiment of the present invention.

[0023] Figure 2 1 is a perspective view showing a lower portion of a retaining ring according to an embodiment of the present invention.

[0024] Figure 3 It is along Figure 2 Cross-sectional view along line Ⅰ-Ⅰ.

[0025] Figure 4 1 is a perspective view showing an upper portion of a support block of a retaining ring according to an embodiment of the present invention.

[0026] Figure 5 1 is a perspective view showing a lower portion of a support block of a retaining ring according to an embodiment of the present invention.

[0027] Figure 6 1 is a perspective view showing an inner ring of a retaining ring according to an embodiment of the present invention without an outer ring.

[0028] Figure 7 is a cross-sectional view showing a support block portion after injection molding according to an embodiment of the present invention.

[0029] Figure 8 It is shown in Figure 7 Cross-sectional view of the post-processing in the injection molded state.

[0030] Fig. 9 1 is a cross-sectional view showing a mold for manufacturing a retaining ring according to an embodiment of the present invention.

[0031] Figures 10a to 10d FIG. 1 is a cross-sectional view showing another example of a support block of a retaining ring according to an embodiment of the present invention.

[0032] (Explanation of Reference Numerals)

[0033] 10: External ring 12: Joint groove

[0034] 14: Slurry discharge groove 20: Internal ring

[0035] 30: Support block 32: Module slot

[0036] 34: Contact protrusion 36: Side groove

[0037] 40: blocking flange 42: inclined surface

[0038] 43: Step surface 44: Concave part

[0039] 50: Lower mold 52: Lower ejector pin

[0040] 60: Upper mold 62: Upper ejector pin DETAILED DESCRIPTION

[0041] The present invention can be subjected to various transformations and can have various embodiments, and specific embodiments are proposed and described in detail. However, it should be understood that this is not intended to limit specific implementation forms, but rather to include all transformations, equivalents and substitutes within the scope of the thought and technology of the present invention. In the description of the present invention, if it is determined that the specific description of the relevant known technology may make the key points of the present invention unclear, the detailed description will be omitted.

[0042] The terms "first", "second", etc. may be used to describe various components, but the components are not limited to the terms. The terms are used only to distinguish one component from another.

[0043] The terms used in this specification are used only to illustrate specific examples and are not intended to limit the present invention. Unless otherwise expressly stated in the article, singular expressions include plural expressions. In this specification, the terms "including" or "having" should be understood to specify the existence of features, numbers, steps, actions, components, parts or combinations thereof recorded in the specification, and do not exclude the existence or additional possibility of one or more other features, numbers, steps, actions, components, parts or combinations thereof in advance.

[0044] In addition, throughout the specification, when the word "connected" is used for explanation, it not only means a direct connection between two or more components, but also means an indirect connection between two or more components through other components, an electrical connection other than a physical connection, or a connection that can form an integral whole although different names are used according to position or function.

[0045] In addition, when it is described as being formed or arranged "on" or "under" each member, the above or below includes not only the case where the two members are in direct contact with each other, but also the case where one or more other members are formed or arranged between the two members. In addition, when expressed as "on or below", it may also include not only the upper direction based on one member, but also the meaning of the lower direction.

[0046] Hereinafter, an embodiment of a retaining ring according to the present invention will be described in detail with reference to the accompanying drawings. In the description with reference to the accompanying drawings, the same reference numerals are given to the same or corresponding components, and the repeated description will be omitted.

[0047] Figure 1 is a perspective view showing an upper portion of a retaining ring according to an embodiment of the present invention; Figure 2 is a perspective view showing the lower portion of a retaining ring according to an embodiment of the present invention; Figure 3 It is along Figure 2 The cross-sectional view along the line Ⅰ-Ⅰ; Figure 4is a perspective view showing the upper portion of a support block of a retaining ring according to an embodiment of the present invention; Figure 5 is a perspective view showing the lower portion of a support block of a retaining ring according to an embodiment of the present invention; Figure 6 is a perspective view showing an inner ring of a retaining ring according to an embodiment of the present invention with an outer ring removed; Figure 7 is a cross-sectional view showing a support block portion after injection molding according to an embodiment of the present invention; Figure 8 It is shown in Figure 7 Cross-sectional view of the post-processing in the injection molded state.

[0048] As shown in the accompanying drawings, a retaining ring according to an embodiment of the present invention may include: an inner ring 20; an outer ring 10, which is formed to surround at least a portion of the inner ring 20 and is made of a material different from that of the inner ring 20; a support block 30, which is inserted into the inner ring 20 and the outer ring 10, and has a contact protrusion 34 protruding from the lower end, and the contact protrusion 34 contacts the end of the ejector pin 62 of the mold.

[0049] Reference Figures 1 to 3 According to an embodiment of the present invention, a retaining ring includes an inner ring 20 and an outer ring 10 manufactured by insert injection molding, wherein the inner ring 20 is made of a metal material such as stainless steel, and the outer ring 10 can be made of a resin material such as PPS, PEEK, and PBN. Accordingly, a part of the retaining ring (the inner ring 20) which is entirely made of expensive PPS, PEEK, and PBN materials is replaced with a metal material, etc., thereby significantly reducing the overall manufacturing cost of the retaining ring, and because the outer ring 10 is made of a resin material, it can exert the same level of grinding performance as before.

[0050] A coupling groove 12 is formed on the upper surface of the outer ring 10 for coupling with the grinding head of the CMP device. The coupling grooves 12 can be arranged at predetermined intervals along the circumferential direction on the upper surface of the outer ring 10, and after injection molding, the inner circumferential surface of the coupling groove 12 can be tapped to form a thread through post-processing. For reference, the upper surface of the outer ring 10 is the surface that is coupled with the grinding head, and the lower surface is the surface that contacts the grinding pad during the grinding process.

[0051] A slurry discharge groove 14 is formed below the outer ring 10. The slurry discharge groove 14 is used to slowly discharge the slurry injected during the grinding process without splashing due to the rotation of the retaining ring and the wafer. The slurry discharge groove 14 can be formed at predetermined intervals along the circumferential direction below the outer ring 10, and can be formed in an oblique direction. In this way, if the slurry discharge groove 14 is formed in an oblique direction, the slurry can be discharged smoothly in the direction of rotation of the retaining ring.

[0052] Reference Figures 4 to 6The support block 30 is roughly made into a cylindrical shape. The support block 30 is a part configured for manufacturing a retaining ring, and plays a role in preventing the ejector pin of the mold from directly retaining the inner ring 20 of the metal material during injection molding. Therefore, the support block 30 can be made of a resin material such as PPS, PEEK, and PBN.

[0053] The support block 30 may be configured to correspond to the portion where the coupling groove 12 is formed. Then, the support block 30 may be recessed from above to form a module groove 32 corresponding to the coupling groove 12. The module groove 32 is formed to be concentric with the coupling groove 12 and have the same diameter, and may be tapped after injection molding.

[0054] A contact protrusion 34 may be protruded from the lower end of the support block 30 to contact the end of the upper ejector pin 62 of the mold. The contact protrusion 34 may protrude into a cylindrical shape having a diameter smaller than that of the support block 30. The contact protrusion 34 is in contact with the upper ejector pin 62 when manufacturing the retaining ring, and the support block 30 can be manufactured in a horizontal state without left-right distortion (horizontal and concentric) together with the lower ejector pin 52. Therefore, the retaining ring is manufactured to be flat and without left-right distortion, thereby preventing one-sided grinding during the grinding process.

[0055] In addition, the contact protrusion 34 is made of a resin material, so when the lower ejector pin 52 applies pressure, even if the upper surface is slightly pressed due to the pressure, it can maintain a flat state and will not be distorted to the left or right.

[0056] A pair of side grooves 36 are formed in the vertical direction on the side of the support block 30, and the side grooves 36 can be located at opposite positions on the side of the support block 30. This is because the resin material for the injection molding flows into the side grooves 36 during injection molding, thereby forming the support block 30 and the outer ring 10 as a whole, so that tapping processing is easy on the support block 30.

[0057] The outer peripheral surface of the support block 30 may be provided with a blocking flange 40 to prevent the slurry from flowing into the inner ring 20. The blocking flange 40 is radially protruding from the outer peripheral surface of the support block 30 to prevent the slurry from flowing into the inner ring 20 along the outer surface of the support block 30.

[0058] In addition, an inclined surface 42 may be formed on the outer peripheral surface of the support block 30 to prevent the slurry from flowing into the inner ring 20 side. Figure 7 , the inclined surface 42 is shown to be inclined downwardly and radially, but this is because the support block 30 is placed upside down, and in fact, the inclined surface 42 may be inclined upwardly and radially. Therefore, even if the slurry flows in from the lower side through the slurry discharge groove 14, the slurry can be blocked and prevented from flowing into the inner ring 20 side along the inclined surface 42. The inclined surface 42 may be formed just below the portion where the blocking flange 40 is formed.

[0059] In the outer peripheral surface of the support block 30, a recessed portion 44 may be formed on the upper side of the stopper flange 40, and the recessed portion 44 may be recessed to have a smaller diameter than the stopper flange 40. If such a recessed portion 44 is formed, when the recessed portion 44 is filled with resin during injection molding, the support block 30 can be stably supported in the vertical direction.

[0060] on the other hand, Figure 7 shows the retaining ring after injection molding is completed, Figure 8 Shows the post-processing after injection molding. Figure 8 In the manufacturing process of the retaining ring, a portion of the upper end of the contact protrusion 34 can be cut off during post-processing. In this way, the cut shape of the upper end of the contact protrusion 34 is already Figure 2 That is, the upper surface of the contact protrusion 34 can be exposed to the outside at the portion where the slurry discharge groove 14 is formed.

[0061] In addition, threads may be formed on the inner peripheral surfaces of the coupling groove 12 and the module groove 32 by tapping.

[0062] Fig. 9 1 is a cross-sectional view showing a mold for manufacturing a retaining ring according to an embodiment of the present invention.

[0063] Referring to the figure, a manufacturing mold for a retaining ring according to an embodiment of the present invention may include: a lower mold 50, in which a retaining ring is placed; an upper mold 60, in which a retaining ring is placed and is closely attached to the upper surface of the lower mold 50; a lower ejector pin 52, which passes through the lower mold 50 and is inserted into a module groove 32 formed in the support block 30 for support; and an upper ejector pin 62, which passes through the upper mold 60 and contacts with the upper surface of the contact protrusion 34 for support.

[0064] The lower mold 50 and the upper mold 60 are molds arranged to manufacture the retaining ring, and the upper mold 60 is in close contact with the upper surface of the lower mold 50 to perform injection molding.

[0065] In one embodiment, the lower ejector pin 52 is inserted into the module groove 32 to hold the support block 30 at the lower side, and the upper ejector pin 62 is kept in direct contact with the contact protrusion 34, thereby holding the support block 30 at the upper side. In this way, the injection molding is performed in a state where the support block 30 is held at the upper and lower sides (in a horizontal and concentric state), so that the retaining ring can maintain flatness, thereby preventing one-sided grinding during the grinding process.

[0066] That is, even if there is a structure such as the support block 30 in the past, there is no portion for holding the upper side, so injection molding is performed in a state where the horizontality and concentricity are not maintained, and there is a problem of one-sided grinding.

[0067] Figures 10a to 10d FIG. 1 is a cross-sectional view showing another example of a support block of a retaining ring according to an embodiment of the present invention.

[0068] Reference Fig.10a In one embodiment, the support block 30 is not provided with the blocking flange 40 , but an inclined surface 42 which is radially inclined upward can be formed along the upper side from the contact protrusion 34 .

[0069] Reference Fig.10b In one embodiment, the support block 30 is not provided with the blocking flange 40 , but an inclined surface 42 which is radially inclined upward can be formed along the upper side from the contact protrusion 34 . In this case, the inclined surface 42 cannot extend to the side surface of the support block 30 .

[0070] Reference Fig.10c In one embodiment, the support block 30 is not provided with the blocking flange 40, but two inclined surfaces 42 that are radially inclined upward can be formed along the upper side from the contact protrusion 34. That is, the two inclined surfaces 42 are continuously arranged, wherein the inclined surface 42 arranged on the lower side is formed relatively flat, and the inclined surface 42 arranged on the upper side can be formed relatively steep.

[0071] Reference Fig.10d In one embodiment, the support block 30 is not provided with a blocking flange 40, but an inclined surface 42 that is radially inclined upward can be formed along the upper side from the contact protrusion 34. Then, a step surface 43 can be formed in a vertical direction on the upper side of the inclined surface 42. The step surface 43 can be formed inwardly in a step shape with respect to the side surface of the support block 30.

[0072] Although the features of the present invention have been described above with reference to the embodiments, it will be understood by those skilled in the art that various modifications and changes can be made to the present invention without departing from the spirit and scope of the present invention described in the claims.

Claims

1. A retaining ring, comprising: Internal ring; an outer ring formed to surround at least a portion of the inner ring and made of a different material from the inner ring; and The support block is inserted into the inner ring and the outer ring, and is provided with a protruding contact protrusion at the lower end so as to contact the end of the ejector pin of the mold.

2. The retaining ring according to claim 1, characterized in that: A coupling groove for coupling with the grinding head is formed on the upper surface of the outer ring, and a module groove corresponding to the coupling groove is formed by being recessed from the upper surface of the support block.

3. The retaining ring according to claim 1, characterized in that: The support block is formed at a position corresponding to the slurry discharge groove, and the slurry discharge groove is formed along the circumferential direction below the outer ring.

4. The retaining ring according to claim 3, characterized in that: The contact protrusion is a part of which is cut off from the upper end by machining during the manufacturing process and is exposed to the outside in the slurry discharge groove.

5. The retaining ring according to claim 1, characterized in that: A blocking flange is arranged on the outer peripheral surface of the support block, and the blocking flange protrudes radially to block the slurry and prevent the slurry from flowing toward the inner ring side.

6. The retaining ring according to claim 5, characterized in that A recessed portion is formed in the outer peripheral surface of the support block on the upper side of the stopper flange, the recessed portion being recessed to have a smaller diameter than the stopper flange.

7. The retaining ring according to claim 1, characterized in that: An inclined surface which is inclined upward and radially is formed on the outer peripheral surface of the support block.

8. The retaining ring according to claim 7, characterized in that The two or more inclined surfaces have mutually different inclination angles.

9. The retaining ring according to claim 1, characterized in that: The inner ring is made of metal material, and the outer ring and the support block are made of resin material.

Images