Retaining ring, polishing head and device for CMP grinding

Abstract

The utility model discloses a retaining ring, a polishing head and a device for CMP (chemical mechanical polishing) grinding, which belong to the technical field of wafer manufacturing, and comprise a ring body and a flat edge part arranged on the ring body, the ring body and the flat edge part enclose to form a limiting groove for placing a wafer, the flat edge part is used for being attached to the flat edge of the wafer, and the limiting groove is used for being attached to the flat edge of the wafer. The ring body is annular, the side wall, close to one side of the axis of the ring body, of the flat edge part is a plane, and the side wall is parallel to the axis. According to the utility model, the technical effects of improving the grinding uniformity, improving the surface quality of the wafer and reducing the reject ratio in the manufacturing process of the wafer with the flat edge are achieved.

Description

Technical Field

[0001] The utility model belongs to the technical field of wafer manufacturing, and particularly relates to a retaining ring, a polishing head and a device for CMP polishing. Background Technique

[0002] With the rapid development of semiconductor technology, the integration degree of integrated circuits has been continuously improved, and the requirement for the planarization of the silicon wafer surface has become increasingly strict. Chemical Mechanical Polishing (CMP) process is a surface planarization treatment method that combines chemical corrosion and mechanical grinding, and is the key technology to achieve nanoscale planarization of the wafer surface, occupying an important position in the wafer manufacturing process.

[0003] At present, in wafer manufacturing technology, CMP equipment mainly adsorbs and transports the wafer to the polishing pad through the polishing head for polishing, and then transports the wafer back to the wafer loading bracket by the polishing head for unloading and placing after polishing. However, the retaining ring of the grinding and polishing head in CMP equipment usually adopts a circular design. When the circular retaining ring is used for processing wafers with a flat-edge shape, the circular retaining ring cannot fit tightly with the wafer with a flat-edge shape, resulting in uneven distribution of the grinding fluid, which is not conducive to reducing the defects and scratches on the wafer surface, will reduce the surface quality of the wafer, and it is difficult to reduce the defective rate during the production process.

[0004] Therefore, it is necessary to provide a new technical solution to solve the above technical problems. Summary of the Utility Model

[0005] The technical problem to be solved by the utility model is the technical problem of poor grinding uniformity, reduced wafer surface quality and high defective rate during the manufacturing process of wafers with flat edges.

[0006] To solve the above technical problems, the utility model provides a retaining ring for CMP grinding, and the retaining ring includes: a ring body and a flat-edge portion provided on the ring body, the ring body and the flat-edge portion enclose a limiting groove for placing the wafer, the flat-edge portion is used to fit with the flat edge of the wafer, the ring body is in a ring shape, the side wall of the flat-edge portion close to the axis of the ring body is a plane, and the side wall is parallel to the axis.

[0007] Optionally, the orthographic projection of the axis on the flat-edge portion is located at the center of the flat-edge portion.

[0008] Optionally, when the diameter of the wafer is 6 inches, the distance range between the center of the side wall and the axis is 72 to 74.5 mm; when the diameter of the wafer is 8 inches, the distance range between the center of the side wall and the axis is 97 to 99.5 mm.

[0009] Optionally, the surface roughness of the side wall is less than or equal to 0.5 nm.

[0010] Optionally, the numerical range of the ring width of the ring body is 1 cm to 3 cm; the ring body and the flat edge portion are integrally formed.

[0011] According to another aspect of the present invention, the present invention further provides a polishing head for CMP polishing. The polishing head for CMP polishing includes the holding ring for CMP polishing as described above, and further includes: a protective cover connected to the ring body, a main body respectively connected to the protective cover and the ring body, and an airbag having an adsorption surface. The airbag is connected to the ring body, and the adsorption surface is located in the limiting groove.

[0012] Optionally, the polishing head for CMP polishing further includes: a driving assembly, and the driving assembly is connected to the main body.

[0013] Optionally, the polishing head for CMP polishing further includes: a connecting member, and the connecting member is respectively connected to the main body and the ring body. The connecting member is made of Teflon material or PVDF material.

[0014] Optionally, the polishing head for CMP polishing further includes: a polishing pad, and the orthographic projection of the ring body along the direction perpendicular to the polishing pad is located on the polishing pad.

[0015] According to another aspect of the present invention, the present invention further provides a device for CMP polishing. The device for CMP polishing includes the polishing head for CMP polishing as described above.

[0016] Beneficial effects:

[0017] The present invention provides a holding ring for CMP polishing. By providing a flat edge portion on the ring body, the ring body and the flat edge portion enclose a limiting groove for placing a wafer. The flat edge portion is used to fit closely with the flat edge of the wafer. The ring body is in a ring shape, and the side wall of the flat edge portion close to the axis line of the ring body is a plane and is parallel to the axis line. In this way, during the manufacturing process of a wafer with a flat edge, the wafer to be polished is placed in the limiting groove formed by the ring body and the flat edge portion, and the flat edge portion will closely fit with the flat edge of the wafer, effectively avoiding the offset and shaking of the wafer during the polishing process, overcoming the uneven distribution of the polishing liquid in the prior art, being beneficial to improving the polishing uniformity, reducing the defects and scratches on the wafer surface, realizing the improvement of the wafer surface quality, and at the same time improving the stability and controllability of the CMP process, and being able to reduce the defective rate during the production process. Thus, the technical effects of improving the polishing uniformity, enhancing the wafer surface quality, and reducing the defective rate are achieved during the manufacturing process of a wafer with a flat edge. Description of the drawings

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0019] Figure 1 It is a schematic structural diagram of a retaining ring for CMP polishing provided by an embodiment of the present invention.

[0020] Figure 2 It is a schematic structural diagram of the axis line and the center in a retaining ring for CMP polishing provided by an embodiment of the present invention.

[0021] Figure 3 It is a schematic structural diagram of a polishing head for CMP polishing provided by an embodiment of the present invention. Specific embodiments

[0022] The following details the embodiments of the present application. The examples of the embodiments are shown in the drawings, where the same or similar reference numerals represent the same or similar elements or elements with the same or similar functions throughout. The embodiments described below with reference to the drawings are exemplary only for explaining the present application and should not be construed as limiting the present application.

[0023] To enable those skilled in the art of this technology to better understand the solutions of the present application, the following will clearly and completely describe the technical solutions in the embodiments of the present application in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all of them. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative efforts fall within the scope of protection of the present application.

[0024] In the embodiments of the present application, "at least one" means one or more; "a plurality" means two or more. In the description of the present application, terms such as "first", "second", "third", etc. are only used for the purpose of distinguishing descriptions and should not be construed as indicating or implying relative importance, nor as indicating or implying order.

[0025] References to "one embodiment" or "some embodiments" or the like described in this specification mean that a particular feature, structure, or characteristic described in connection with the embodiment is included in one or more embodiments of the present application. Thus, the terms "comprising", "including", "having" and their variations in this specification all mean "including but not limited to", unless otherwise specifically emphasized in other ways. It should be noted that in the embodiments of the present application, "and / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B may represent: A exists alone, A and B exist simultaneously, and B exists alone.

[0026] It should be pointed out that in the embodiments of the present invention, when a component is referred to as "fixed to" another component, it can be directly on the other component or there may also be an intermediate component. When a component is considered to be "connected to" another component, it can be directly connected to the other component or there may be an intermediate component at the same time. When a component is considered to be "disposed on" another component, it can be directly disposed on the other component or there may be an intermediate component at the same time. At the same time, in the embodiments of the present application, "connection" can also be understood as electrical connection, and the connection of two electrical components can be a direct or indirect connection between the two electrical components. For example, the connection of A and B can be either a direct connection between A and B or an indirect connection between A and B through one or more other electrical components. The terms "vertical", "horizontal", "left", "right" and similar expressions used in the embodiments of the present invention are only for illustrative purposes and are not intended to limit the present invention.

[0027] An embodiment of the present invention provides a holding ring for CMP polishing. Please refer to Figures 1 to 2 as shown Figure 1 which is a schematic structural view of a holding ring for CMP polishing provided by an embodiment of the present invention. Figure 2 which is a schematic structural view of the axis 12 and the center 211 in a holding ring for CMP polishing provided by an embodiment of the present invention. A holding ring for CMP polishing provided by Embodiment 1 of the present invention includes a ring body 1 and a flat edge portion 2. The flat edge portion 2 is disposed on the ring body 1. The ring body 1 and the flat edge portion 2 enclose a limiting groove 11 for placing a wafer. The flat edge portion 2 is used to fit with the flat edge of the wafer. The ring body 1 is in a ring shape. The side wall 21 of the flat edge portion 2 close to the axis 12 of the ring body 1 is in a plane, and the side wall 21 is parallel to the axis 12.

[0028] Among them, the interior of the limiting groove 11 has a space for accommodating the wafer, and the side wall 21 is a side surface of the flat edge portion 2 close to the limiting groove 11. The side wall 21 is a plane, so that the side wall 21 and the flat edge of the wafer fit tightly together. The flat side wall 21 and the axis 12 of the ring body 1 are parallel to each other, that is, the surface of the side wall 21 is a plane parallel to the axis located at the center position of the ring body 1.

[0029] The retaining ring is used for chemical mechanical polishing, which is a commonly used process in the field of semiconductor manufacturing. The basic principle of this process is to use a chemical solution to react with the surface of the wafer to be processed to convert insoluble substances into soluble substances, and then remove the soluble substances on the surface of the wafer to be processed by mechanical friction. This process combines chemical reaction with mechanical action to remove the surface material of the wafer to be processed to achieve a flattening effect.

[0030] In this embodiment, by setting the flat edge portion 2 on the ring body 1, the ring body 1 and the flat edge portion 2 enclose a limit groove 11 for placing the wafer, the flat edge portion 2 is used to fit with the flat edge of the wafer, the ring body 1 is annular, and the side wall 21 of the flat edge portion 2 close to the axis center line 12 of the ring body 1 is plane, and the side wall 21 is parallel to the axis center. In this way, in the manufacturing process of wafers with flat edges, the wafer to be ground is placed in the limit groove 11 formed by the ring body and the flat edge portion 2, and the flat edge portion 2 will fit closely with the flat edge of the wafer, effectively avoiding the deviation and shaking of the wafer during the grinding process, overcoming the uneven distribution of the grinding liquid in the prior art, and being conducive to improving the grinding uniformity, reducing the defects and scratches on the wafer surface, achieving the improvement of the wafer surface quality, and improving the stability and controllability of the CMP process, and can reduce the defect rate in the production process. Thereby achieving the technical effect of improving the grinding uniformity, improving the wafer surface quality, and reducing the defect rate in the manufacturing process of wafers with flat edges.

[0031] As an implementation mode, the orthographic projection of the axis line 12 on the flat edge portion 2 is located at the center 211 of the flat edge portion 2, that is, the flat edge portion 2 is symmetrically distributed relative to the orthographic projection of the axis line 12 on the flat edge portion 2. When observed from a direction perpendicular to the axis line 12 of the ring body 1, the projection point of the axis line 12 falls exactly on the geometric center of the flat edge portion 2, so that the flat edge portion 2 supports the flat edge of the wafer more evenly, effectively avoiding the wafer shift and shaking caused by uneven local force during the grinding process, and enhancing the stability of the wafer during the grinding process.

[0032] In some embodiments, when the diameter of the wafer is 6 inches, the distance between the center 211 of the sidewall 21 and the axis line 12 ranges from 72 mm to 74.5 mm. That is, assuming the distance between the center 211 of the sidewall 21 and the axis line 12 is H1, then 72 mm ≤ H1 ≤ 74.5 mm at this time. When the diameter of the wafer is 8 inches, the distance between the center 211 of the sidewall 21 and the axis line 12 ranges from 97 mm to 99.5 mm. That is, assuming the distance between the center 211 of the sidewall 21 and the axis line 12 is H2, then 97 mm ≤ H2 ≤ 99.5 mm at this time. For wafers of different diameters, the best adaptation effect can be achieved, reducing the grinding problems caused by size mismatch.

[0033] In some embodiments, the surface roughness of the sidewall 21 is less than or equal to 0.5 nm. That is, assuming the surface roughness of the sidewall 21 of the flat edge part 2 is Ra, then Ra ≤ 0.5 nm. The surface roughness of the sidewall 21 less than or equal to 0.5 nm will directly reduce the friction and wear between the wafer and the sidewall 21 during the grinding process, avoiding scratches and contamination on the wafer surface caused by surface roughness.

[0034] In some embodiments, the numerical range of the ring width of the ring body 1 is from 1 cm to 3 cm. The ring body 1 and the flat edge part 2 are integrally formed, enabling the ring body 1 to provide sufficient support while avoiding material waste and increased processing difficulty caused by excessive size, and adopting an integral forming process to ensure a seamless connection between the ring body 1 and the flat edge part 2, reducing performance degradation and safety hazards caused by poor connection, which is beneficial to improving the overall performance and reliability of the retaining ring.

[0035] To elaborate on a polishing head for CMP grinding provided by the present utility model, the above-mentioned Embodiment 1 elaborated on a retaining ring for CMP grinding. Based on the same inventive concept, this application also provides a polishing head for CMP grinding, as detailed in Embodiment 2.

[0036] Please refer to Figure 3 , Figure 3It is a schematic structural diagram of a polishing head for CMP polishing provided by an embodiment of the present utility model. Embodiment two of the present utility model provides a polishing head for CMP polishing. The polishing head for CMP polishing includes the above-mentioned retaining ring for CMP polishing, and further includes a protective cover 3, a main body 4, and an airbag 5. The protective cover 3 is connected to the ring body 1, the main body 4 is respectively connected to the protective cover 3 and the ring body 1, the airbag 5 has an adsorption surface 51 for adsorbing a wafer, the airbag 5 is connected to the ring body 1, and the adsorption surface 51 is located inside the limit groove 11. The protective cover 3 is tightly connected to the ring body 1, effectively resisting vibration and impact during the polishing process, and providing protection for the internal components of the entire polishing head. The main body 4 is respectively connected to the protective cover 3 and the ring body 1 to form the main structural framework of the polishing head. Those skilled in the art can understand that in the polishing head for CMP polishing provided by the embodiment of the present utility model, no specific limitation is imposed on the specific structure of the airbag 5, as long as the adsorption surface 51 of the airbag 5 can ensure that the wafer is tightly adsorbed during the polishing process to prevent the wafer from shifting or shaking.

[0037] In some embodiments, embodiment two of the present utility model provides a polishing head for CMP polishing, which further includes a driving component. The driving component is connected to the main body 4. The driving component includes a cylinder, a motor, etc. During the polishing process, the driving component can drive the polishing head to move along a predetermined trajectory and speed, ensuring that the wafer can be evenly polished.

[0038] In some embodiments, embodiment two of the present utility model provides a polishing head for CMP polishing, which further includes a connecting piece. The connecting piece is respectively connected to the main body 4 and the ring body 1, and the connecting piece is made of Teflon material or PVDF material. The connecting piece made of Teflon material or PVDF material has good wear resistance, corrosion resistance, and chemical stability, which can ensure that the connecting piece maintains stable performance and reliable connection during long-term use, effectively resisting wear and corrosion generated during the polishing process, and extending the service life of the polishing head. The main body 4 can be directly connected to the ring body 1 through the connecting piece, so that the ring body 1 is fixed on the main body 4. Then, the protective cover 3 is sleeved outside the main body 4, and a space for installing the internal components of the polishing head is formed by enclosing the protective cover 3, the ring body 1, and the main body 4. Those skilled in the art can understand that in the polishing head for CMP polishing provided by the embodiment of the present utility model, no specific limitation is imposed on the specific structure of the connecting piece, as long as the ring body 1 and the main body 4 can be connected through the connecting piece.

[0039] In some embodiments, embodiment two of the present utility model provides a polishing head for CMP polishing, which further includes a polishing pad. The orthographic projection of the ring body 1 along the direction perpendicular to the polishing pad is located on the polishing pad. The polishing pad is used to directly contact the wafer and perform polishing treatment. The ring body 1 being directly opposite to the polishing pad is beneficial to ensuring that the wafer can be evenly polished.

[0040] The utility model provides a polishing head for CMP grinding, wherein a flat edge portion 2 is arranged on a ring body 1, the ring body 1 and the flat edge portion 2 enclose a limiting groove 11 for placing a wafer, the flat edge portion 2 is used to fit with the flat edge of the wafer, the ring body 1 is annular, and a side wall 21 of the flat edge portion 2 close to the axis center line 12 of the ring body 1 is a plane, and the side wall 21 is parallel to the axis center line. In this way, in the manufacturing process of wafers with flat edges, the wafer to be ground is placed in the limiting groove 11 enclosed by the ring body and the flat edge portion 2, the flat edge portion 2 will fit closely with the flat edge of the wafer, effectively avoiding the deviation and shaking of the wafer during the grinding process, overcoming the uneven distribution of the grinding liquid in the prior art, being conducive to improving the grinding uniformity, reducing the defects and scratches on the wafer surface, and improving the surface quality of the wafer, while improving the stability and controllability of the CMP process, and being able to reduce the defect rate in the production process. Thereby achieving the technical effect of improving grinding uniformity, enhancing wafer surface quality and reducing defective rate in the manufacturing process of wafers with flat edges.

[0041] In order to explain in detail a device for CMP grinding provided by the utility model, the above-mentioned embodiment one explains in detail a retaining ring for CMP grinding. Based on the same utility model concept, the present application also provides a device for CMP grinding, see embodiment three for details.

[0042] The third embodiment of the present invention provides a device for CMP grinding, and the device for CMP grinding includes the above-mentioned polishing head for CMP grinding.

[0043] Among them, the third embodiment of the present invention provides a device for CMP grinding, which can also include a grinding liquid supply component, and the grinding liquid supply component is used to supply the grinding liquid to the above-mentioned polishing pad.

[0044] The utility model provides a device for CMP polishing. By providing a flat edge part 2 on the ring body 1, a limiting groove 11 for placing a wafer is formed by enclosing the ring body 1 and the flat edge part 2. The flat edge part 2 is used to fit closely with the flat edge of the wafer. The ring body 1 is in a ring shape, and the side wall 21 of the flat edge part 2 on the side close to the axis line 12 of the ring body 1 is a plane, and the side wall 21 is parallel to the axis line. In this way, during the manufacturing process of a wafer with a flat edge, the wafer to be polished is placed in the limiting groove 11 formed by enclosing the ring body and the flat edge part 2, and the flat edge part 2 will fit closely with the flat edge of the wafer, effectively avoiding the offset and shaking of the wafer during the polishing process, overcoming the uneven distribution of the polishing liquid in the prior art, being beneficial to improving the polishing uniformity, reducing the defects and scratches on the wafer surface, realizing the improvement of the wafer surface quality, and at the same time improving the stability and controllability of the CMP process, and being able to reduce the defective rate during the production process. Thus, during the manufacturing process of a wafer with a flat edge, the technical effects of improving the polishing uniformity, enhancing the wafer surface quality, and reducing the defective rate are achieved.

[0045] Finally, it should be noted that the above specific embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the examples, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the spirit and scope of the technical solutions of the present invention, and they should all be covered within the scope of the claims of the present invention.

Claims

1. A holding ring for CMP polishing, characterized in that, The holding ring includes: a ring body and a flat edge portion provided on the ring body. The ring body and the flat edge portion enclose a limiting groove for placing a wafer. The flat edge portion is used to fit with the flat edge of the wafer. The ring body is annular, and the side wall of the flat edge portion on the side close to the axis line of the ring body is a plane, and the side wall is parallel to the axis line.

2. The retaining ring for CMP polishing according to claim 1, characterized in that: The orthographic projection of the axis line on the flat edge portion is located at the center of the flat edge portion.

3. The retaining ring for CMP polishing according to claim 1, wherein: When the diameter of the wafer is 6 inches, the distance range between the center of the side wall and the axis line is 72 to 74.5 mm; when the diameter of the wafer is 8 inches, the distance range between the center of the side wall and the axis line is 97 to 99.5 mm.

4. The retaining ring for CMP polishing according to claim 1, characterized in that: The surface roughness of the side wall is less than or equal to 0.5 nm.

5. The holding ring for CMP polishing according to claim 1, characterized in that: The numerical range of the ring width of the ring body is 1 cm to 3 cm; the ring body and the flat edge portion are integrally formed.

6. A polishing head for CMP polishing, characterized in that, The polishing head for CMP grinding includes the holding ring for CMP grinding according to any one of claims 1 to 5, and further includes: a cover connected to the ring body, a main body respectively connected to the cover and the ring body, and an airbag having an adsorption surface. The airbag is connected to the ring body, and the adsorption surface is located in the limiting groove.

7. The polishing head for CMP polishing according to claim 6, characterized in that, The polishing head for CMP grinding further includes: a driving component, and the driving component is connected to the main body.

8. The polishing head for CMP polishing according to claim 6, wherein, The polishing head for CMP grinding further includes: a connecting piece, and the connecting piece is respectively connected to the main body and the ring body. The connecting piece is made of Teflon material or PVDF material.

9. The polishing head for CMP polishing according to claim 6, characterized in that, The polishing head for CMP grinding further includes: a polishing pad, and the orthographic projection of the ring body in the direction perpendicular to the polishing pad is located on the polishing pad.

10. An apparatus for CMP polishing, characterized in that, The device for CMP grinding includes the polishing head for CMP grinding according to any one of claims 6 to 9.

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