Retaining ring, grinding head mechanism and grinding device

Abstract

The utility model provides a retaining ring, a grinding head mechanism and a grinding device. The material of at least the surface, making contact with a polishing pad, of the retaining ring is the same as the material of a wafer serving as a grinding object. At least the surface of the holding ring in contact with the polishing pad is made of the same material as the wafer to be polished, so that the temperature difference between the part of the surface of the polishing pad in contact with the surface of the holding ring and the part of the surface of the polishing pad in contact with the surface of the wafer can be eliminated. In addition, the thickness of the retaining ring can be controlled to be an optimal value relative to the thickness of the wafer, and finally, the retaining ring capable of improving the overall flatness of the wafer and suppressing edge collapse can be provided.

Description

Technical Field

[0001] The present application relates to a retaining ring, a grinding head mechanism and a grinding device for CMP processing, and in particular to a wafer retaining ring, a grinding head mechanism and a grinding device for grinding semiconductor wafers and the like. Background Art

[0002] When forming device structures such as transistors or wiring structures on the surface of various semiconductor wafers such as silicon (Si), silicon carbide (SiC), gallium nitride (GaN), and gallium arsenide (GaAs), it is necessary to use an exposure device to transfer the pattern of the area that determines the device structure or wiring structure onto the wafer.

[0003] At this time, if the wafer surface is not flat, the pattern cannot be transferred correctly, which eventually leads to abnormalities in the formed device structure or wiring structure. Therefore, a CMP (chemical mechanical polishing) device is needed to flatten the wafer surface.

[0004] Furthermore, in the manufacturing process of semiconductor devices, it is sometimes necessary to stack structures such as transistor elements and wiring on the surface of a wafer, and a polishing process based on CMP processing is also required in the process of forming this stacked structure.

[0005] When using a CMP device for CMP processing, it is necessary to impregnate the polishing pad with slurry, press the polishing head holding the wafer onto the polishing plate, and make the polishing head and the polishing plate slide against each other while rotating. The slurry used in the CMP process contains abrasives or abrasive particles formulated according to the composition or structure of the polishing object and the purpose of polishing. The surface of the wafer is flattened by mechanical polishing combined with the chemical reaction of the abrasive and abrasive particles with the wafer surface.

[0006] The grinding head of the CMP device is equipped with a retaining ring (also called a guide ring) to prevent the wafer from flying out of the grinding head when the grinding head and the polishing plate slide relative to each other. Generally, the retaining ring is usually made of resin materials such as polyetheretherketone (PEEK) resin, polyphenylene sulfide (PPS) resin, epoxy glass, etc. During CMP processing, the surface of the retaining ring facing the polishing pad will slide relative to the polishing pad like the wafer, so the impact on the overall flatness of the wafer will vary depending on the material used for the retaining ring.

[0007] When a wafer is subjected to CMP processing, the flatness near the edge of the wafer may be worse than the flatness of the center of the wafer, that is, edge collapse may occur.

[0008] Since the wafer surface is not flat in the area where the edge collapse occurs, the pattern cannot be transferred correctly, and the final component structure and wiring structure will be abnormal, which is the main reason for the reduction in yield. In addition, in order to avoid the reduction in yield, if the area where the edge collapse occurs is used as the edge exclusion area (the area where the semiconductor components are not manufactured on the outermost circle of the wafer), as the area where the edge collapse occurs becomes larger, the area used to manufacture semiconductor components will become narrower, resulting in a decrease in the number of semiconductor components that can be produced by a single wafer itself. Both the reduction in yield and the reduction in production quantity will lead to a decrease in the production efficiency of semiconductor equipment.

[0009] One of the factors causing edge collapse is local wear of the inner surface of the retaining ring (the side that stops the wafer). To solve this problem, Patent Document 1 (JP2016140970A) discloses using a ceramic material with high fracture toughness in the retaining ring to alleviate the edge collapse caused by wear on the inner side of the retaining ring.

[0010] In the grinding device of Patent Document 1, by manufacturing the retaining ring with a ceramic material having a fracture toughness of 4 MPa·m1 / 2 or more, the generation of a notch on the inner side surface of the retaining ring is suppressed when colliding with a wafer, thereby reducing the uneven wear of the inner side surface of the retaining ring. By reducing the uneven wear of the inner side surface of the retaining ring, the edge collapse can be alleviated to a certain extent.

[0011] However, during the CMP process of the wafer, there are other factors that may cause the edge collapse of the wafer. Summary of the invention

[0012] The present application aims to solve the problem that the existing retaining ring may cause the edge of the wafer to collapse and affect the flatness of the wafer during the CMP processing of the wafer. The present application provides a retaining ring, a grinding head mechanism and a grinding device that can improve the overall flatness of the wafer and inhibit the edge collapse of the wafer.

[0013] The technical solution of this application is as follows:

[0014] In a first aspect, the present application provides a retaining ring. The retaining ring of the present application is a retaining ring for a wafer grinding device, characterized in that the material of at least the surface of the retaining ring that contacts the polishing pad is the same as the material of the wafer to be ground.

[0015] By making at least the surface of the retaining ring that contacts the polishing pad with the same material as the wafer that is to be polished, the temperature change difference between the part where the polishing pad surface contacts the retaining ring surface and the part where the polishing pad surface contacts the wafer surface is eliminated, and the thickness of the retaining ring can be controlled to an optimal value relative to the thickness of the wafer, thereby avoiding edge collapse of the wafer during CMP processing, resulting in a decrease in yield or a reduction in the number of samples collected, and a decrease in the productivity of semiconductor devices.

[0016] Optionally, the entire material of the annular retaining ring is the same as the material of the wafer to be polished.

[0017] By using the same material as the wafer to make the entire retaining ring, it is easy to manufacture and has good integrity.

[0018] Optionally, the retaining ring is provided with a gap for supplying slurry to the grinding surface of the wafer.

[0019] By providing a gap on the retaining ring, it is ensured that the slurry is evenly distributed on the grinding surface of the wafer during the grinding process.

[0020] Optionally, the retaining ring includes an annular component made of resin and a contact layer made of the same material as the wafer, and the contact layer is arranged on the lower surface of the annular component.

[0021] By dividing the retaining ring into a circular ring-shaped component made of resin and a contact layer made of the same material as the wafer, the manufacturing cost of the retaining ring is reduced while ensuring the effect achieved by the present application.

[0022] Optionally, the thickness of the contact layer is equal to or greater than the thickness of the wafer to be ground.

[0023] The design that the thickness of the contact layer is equal to or greater than the thickness of the wafer to be ground ensures that the wafer is confined within the contact layer of the same material during the grinding process.

[0024] Optionally, the contact layer is annular and is provided with a gap for supplying slurry to the grinding surface of the wafer.

[0025] By setting a gap on the contact layer, it is ensured that the slurry is evenly distributed on the grinding surface of the wafer during the grinding process.

[0026] Optionally, the contact layer includes a plurality of thin sheets made of the same material as the wafer and arranged circumferentially below the annular component.

[0027] By setting a thin sheet of the same material as the wafer under the contact layer, the temperature difference between the part where the surface of the polishing pad contacts the surface of the retaining ring and the part where the surface of the polishing pad contacts the surface of the wafer can be eliminated, and replacement is convenient after wear.

[0028] Optionally, at least the surface of the retaining ring in contact with the polishing pad is made of any one of silicon, silicon carbide, gallium nitride and gallium arsenide.

[0029] In a second aspect, the present application further provides a grinding head mechanism, which includes a grinding head and a retaining ring according to the first aspect installed on the grinding head.

[0030] In a third aspect, the present application further provides a grinding device, which includes a polishing plate mechanism and the grinding head mechanism in the second aspect arranged above the polishing plate mechanism.

[0031] By using a retaining ring having at least a surface in contact with the polishing pad and a material of the same material as the wafer to be polished, the temperature difference between the portion where the polishing pad surface contacts the retaining ring surface and the portion where the polishing pad surface contacts the wafer surface can be eliminated. In addition, the thickness of the retaining ring can be controlled to an optimal value relative to the thickness of the wafer. As a result, a polishing head mechanism and a polishing device are provided that can improve the overall flatness of the wafer and suppress edge collapse. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 is a schematic diagram of a grinding device in an embodiment of the present application;

[0033] Figure 2 is a schematic diagram of a retaining ring in the first embodiment of the present application;

[0034] Figure 3 is a schematic diagram of a retaining ring with a gap in a second embodiment of the present application;

[0035] Figure 4 Schematic diagram of the difference in force between the polishing pad and the wafer near the edge of the wafer and near the center of the wafer in an embodiment of the present application;

[0036] Figure 5 is a schematic diagram of a retaining ring in a third embodiment of the present application;

[0037] Figure 6 This is a side view of a retaining ring in a third embodiment of the present application.

[0038] Figure 1 to Figure 6 Including:

[0039] 1. Grinding device; 2. Grinding head mechanism; 3. Polishing plate mechanism; 10. Grinding head; 11. Wafer holding part; 12. Holding ring; 13. Grinding head rotating spindle; 14. Polishing plate; 15. Polishing plate rotating spindle; 16. Polishing pad; 20. Gap; 21. Holding ring; 22. Annular component; 23. Thin sheet; P. The polishing pad is subjected to pressure from the holding ring; M. The force between the polishing pad and the wafer near the edge of the wafer; N. The force between the polishing pad and the wafer near the center of the wafer. DETAILED DESCRIPTION

[0040] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, the present application is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0041] During CMP processing, the surface of the retaining ring opposite to the polishing pad also slides relative to the polishing pad, just like the wafer, so the surface of the retaining ring opposite to the polishing pad generates heat due to friction. When the material of the retaining ring is different from that of the wafer, due to their different friction coefficients, when the surface of the polishing pad slides relative to each other, there will be a difference in temperature between the part of the polishing pad in contact with the retaining ring surface and the part of the polishing pad in contact with the wafer surface.

[0042] Furthermore, since the CMP process also involves a swinging motion, the portion of the polishing pad surface that contacts the retaining ring also grinds the wafer, so the temperature difference on the polishing pad surface also affects the overall flatness of the wafer after grinding.

[0043] In addition, since the edge of the wafer is closer to the retaining ring than the center of the wafer, the edge of the wafer is more easily affected by the temperature of the retaining ring surface, causing the edge of the wafer and the center of the wafer to be ground under different temperature environments. Therefore, the different materials of the wafer and the retaining ring may become the main reason for edge collapse.

[0044] In addition, when the material of the retaining ring is different from that of the chip and is a material that is difficult to process with high precision, the thickness of the retaining ring cannot be processed to be consistent with the thickness of the chip due to the processing accuracy. Therefore, the thickness of the retaining ring cannot be adjusted to the optimal value, that is, there is a height difference between the retaining ring and the chip on the polishing pad in the thickness direction.

[0045] For example, if the material of the retaining ring is resin, there is a method of forming by injection molding in the processing method of resin. In this method, the resin is prone to offset or thermal deformation during processing, so it is difficult to perform high-precision processing. Therefore, due to the problem of its processing method, the thickness of the resin retaining ring will have a processing error of about 25μm. Therefore, it is impossible to control the thickness of the retaining ring to the optimal value relative to the thickness of the wafer.

[0046] It is well known that the thickness difference between the wafer and the retaining ring will affect the edge profile of the wafer. If the thickness difference cannot be properly controlled, edge collapse will occur.

[0047] In view of the above situation, the present application provides a method for improving the overall flatness of the wafer by using the same material as the wafer to be polished in a retaining ring, thereby eliminating the temperature difference between the portion of the polishing pad surface that contacts the retaining ring surface and the portion of the polishing pad surface that contacts the wafer surface, and providing a retaining ring that can suppress the collapse of the wafer edge by controlling the thickness of the retaining ring to an optimal value relative to the thickness of the wafer, that is, adjusting the height difference between the retaining ring and the wafer in the thickness direction to an optimal state.

[0048] Figure 1 A grinding device 1 according to an embodiment of the present application is shown. The grinding device 1 is used for CMP (chemical mechanical polishing) of a disc-shaped grinding object such as a semiconductor wafer. The grinding device 1 is composed of a grinding head mechanism 2 and a polishing plate mechanism 3. The material of the wafer to be ground in this embodiment is single crystal silicon (Si). However, the material of the wafer to be ground is not limited to this, and for example, it can also be silicon carbide (SiC), gallium nitride (GaN), gallium arsenide (GaAs), etc.

[0049] The grinding head mechanism 2 is used to hold the semiconductor wafer (hereinafter referred to as the wafer) during the grinding process, that is, to limit the position of the wafer and press the wafer on the grinding platform of the polishing plate mechanism 3. The grinding head mechanism 2 is also used to drive the wafer to rotate or swing. The polishing plate mechanism 3 is configured to grind the wafer on the grinding platform of the polishing plate by rotating the polishing plate.

[0050] First, the details of the polishing head mechanism 2 will be described. The polishing head mechanism 2 includes a polishing head 10, a wafer holding portion 11, and a holding ring 12. The structure of the holding ring 12 will be described in detail later.

[0051] The grinding head 10 is a main component of the grinding head mechanism 2. A grinding head rotating spindle 13 is provided at the upper end of the grinding head 10. A driving shaft for driving the grinding head 10 to rotate is provided inside the grinding head rotating spindle 13, and the driving shaft is driven by a motor.

[0052] A wafer holding portion 11 for holding a wafer is provided below the polishing head mechanism 2. The wafer holding portion 11 may include a member for limiting the position of the wafer, such as a ceramic plate, a sealing gasket, or a film.

[0053] When the wafer holding part 11 uses a ceramic plate, an adhesive such as wax needs to be applied to the opposite side of the polished surface of the wafer and pasted on the ceramic plate to hold the wafer. When a sealing pad is used, wax is not used, but the wafer is adsorbed on the sealing pad and held.

[0054] The wafer holding portion 11 further includes a flexible member, such as a film, provided on a ceramic plate or a sealing gasket, thereby being able to absorb and adjust the pressure applied by the chamber inside the polishing head 10 .

[0055] An annular holding ring 12 is provided around the wafer on the lower surface of the wafer holding portion 11. The holding ring 12 surrounds and holds the wafer to be polished.

[0056] Next, the polishing plate mechanism 3 will be described. The polishing plate mechanism 3 includes a polishing plate 14 and a polishing plate rotating spindle 15. In addition, the polishing plate mechanism 3 in this embodiment is generally a platform (or a flat plate).

[0057] The polishing plate 14 is a generally disc-shaped member for polishing the wafer pressed by the grinding head 10. The polishing pad 16 is mounted on the upper surface of the polishing plate 14, that is, on the polishing surface for polishing the wafer. The polishing pad 16 can be made of a hard material such as a polyurethane pad or a soft material such as a non-woven fabric pad or a sliding pad.

[0058] In a first aspect, the present application provides a retaining ring for a wafer grinding device. Next, the retaining ring 12 is described in detail. Figure 2 (a) is a plan view of the retaining ring 12 viewed from the side in contact with the polishing pad 16 of the polishing plate 14. Figure 2 (b) is a side view of the retaining ring 12 as seen from the side. The inner diameter of the retaining ring 12 may be any size corresponding to the size of the wafer to be polished (50 mm, 100 mm, 150 mm, 200 mm, 300 mm, etc.).

[0059] The retaining ring 12 involved in the present application only needs to be made of the same material as the wafer to be polished as at least one side in contact with the polishing pad. Of course, the entire retaining ring 12 can also be made of the same material as the wafer to be polished.

[0060] In one possible implementation, Figure 2 The entirety of the retaining ring 12 shown is made of silicon material. Figure 3 As shown, a plurality of slits 20 for supplying slurry to the polishing surface of the wafer during the CMP process can be arbitrarily provided on the surface of the retaining ring 12 that contacts the polishing pad 16 . Figure 3 (a) is a plan view of the retaining ring 12 as viewed from the side in contact with the polishing pad 16 of the polishing plate 14 . Figure 3 (b) is a side view of the retaining ring 12. Through the gap 20, the slurry can be smoothly supplied to the polishing surface of the wafer during the CMP process, ensuring that the slurry is uniform on the wafer surface during the polishing process.

[0061] When the entire retaining ring 12 is made of silicon material, the thickness of the retaining ring 12 can be controlled in units of μm. That is, when the entire retaining ring 12 is made of silicon material, the error in thickness relative to the silicon wafer can be suppressed to less than 1 μm. For example, in the case of a 200 mm silicon wafer, its thickness is 725 μm. When the retaining ring 12 is made of silicon, the thickness of the retaining ring 12 can be controlled within the range of 724 μm to 726 μm, and the wafer and the retaining ring 12 can be roughly in the same plane relative to the polishing pad 16.

[0062] In contrast, when the retaining ring is made of resin material, the thickness of the retaining ring 12 can only be controlled within the range of 700μm to 750μm. It is difficult to control the thickness of the retaining ring to the optimal thickness value relative to the thickness of the chip, that is, it is difficult to control the height difference between the retaining ring and the chip in the height direction relative to the polishing pad.

[0063] Figure 4 (a) is a schematic diagram showing the difference in force between the polishing pad 16 and the wafer near the edge of the wafer and near the center of the wafer when a retaining ring 12 made of a resin material and having a thickness of 750 μm (offset by +25 μm relative to the thickness of the wafer) is used.

[0064] In this case, since the retaining ring 12 and the wafer are offset by +25 μm in the thickness direction, the polishing pad 16 is subjected to a large load from the retaining ring 12 (indicated by P in the figure). Due to this load, a stress that bulges toward the wafer side is generated on the polishing pad 16 directly below the wafer edge. Due to this stress, the force applied to the polishing pad 16 and the wafer edge becomes larger. Therefore, compared with the force applied between the polishing pad 16 and the wafer center, the force applied between the polishing pad 16 and the wafer edge is larger, that is, M>N, which increases the possibility of edge collapse.

[0065] Figure 4 (b) is a schematic diagram showing the difference in force between the polishing pad 16 and the wafer near the edge of the wafer and near the center of the wafer when a retaining ring 12 made of silicon material with a thickness of 725 μm is used (the wafer and the retaining ring 12 are in the same plane relative to the polishing pad 16).

[0066] In this case, since the retaining ring 12 is not offset in the thickness direction relative to the wafer, that is, there is no height difference, the polishing pad 16 will not be subjected to a large load from the retaining ring 12, and thus no stress that bulges toward the wafer side will be generated on the polishing pad 16 directly below the wafer edge, thereby not having a large impact on the force applied to the polishing pad 16 and the wafer edge. Therefore, the magnitude of the force applied to the polishing pad 16 and the wafer center will not be unbalanced with the magnitude of the force applied to the polishing pad 16 and the wafer edge, that is, M=N, which ultimately reduces the possibility of edge collapse.

[0067] In addition, during CMP processing, as with the wafer, the surfaces of the retaining ring and the polishing pad facing each other also slide on the polishing pad, so heat is generated by friction on the surfaces of the retaining ring and the polishing pad facing each other. However, since the material of the retaining ring 12 in this embodiment is silicon, which is the same as the material of the wafer, and the friction coefficient is the same, there is no temperature difference between the portion where the surface of the polishing pad contacts the surface of the retaining ring and the portion where the surface of the polishing pad contacts the surface of the wafer, thereby reducing the influence on the flatness of the entire wafer after grinding and reducing the possibility of causing edge collapse.

[0068] In this embodiment, the material of the wafer is silicon, but the present application is not limited to this when implemented, and the material of the wafer may also be silicon (Si), silicon carbide (SiC), gallium nitride (GaN), gallium arsenide (GaAs), etc. Therefore, the material of the entire retaining ring is not limited to silicon, as long as it is the same as the material of the wafer to be polished, that is, it may also be silicon carbide (SiC), gallium nitride (GaN), gallium arsenide (GaAs), etc.

[0069] In summary, in this embodiment, the entire retaining ring 12 used in the grinding device 1 is made of silicon, which is the same material as the wafer to be ground, so that the temperature difference between the portion where the surface of the polishing pad contacts the surface of the retaining ring and the portion where the surface of the polishing pad contacts the surface of the wafer can be eliminated. In addition, the thickness of the retaining ring can be controlled to an optimal value relative to the thickness of the wafer, that is, there can be no height difference between the retaining ring and the wafer on the polishing pad in the thickness direction. In addition, due to these effects, this embodiment can provide a retaining ring that can reduce the impact on the overall flatness of the wafer and can suppress edge collapse. In addition, the entire retaining ring is made of wafer and silicon material, and compared with the case where the entire retaining ring is made of resin, it is possible to prevent local wear of the inner side of the retaining ring, thereby suppressing the edge collapse of the wafer.

[0070] In addition, in another possible embodiment, the retaining ring 12 used in the grinding device 1 only needs to have at least the surface in contact with the polishing pad 12 made of the same material as the wafer to be ground. For example, the retaining ring may include an annular component made of resin and a contact layer made of the same material as the wafer, and the contact layer is disposed on the lower surface of the annular component. The thickness of the contact layer is equal to or greater than the thickness of the wafer to be ground. The contact layer is concentrically mounted below the annular component, and the present application does not limit the method of fixing the contact layer on the annular component, and any fixing method may be used. On the side of the contact layer in contact with the polishing pad, a plurality of gaps for supplying slurry to the grinding surface of the wafer during CMP processing may be arbitrarily set.

[0071] In this embodiment, the material of the wafer is silicon, but the present application is not limited thereto when implemented, and the material of the wafer may also be silicon (Si), silicon carbide (SiC), gallium nitride (GaN), gallium arsenide (GaAs), etc. Therefore, the material of the contact layer of the retaining ring is not limited to silicon, as long as it is the same as the material of the wafer to be polished, that is, it may also be silicon carbide (SiC), gallium nitride (GaN), gallium arsenide (GaAs), etc.

[0072] In addition, in another possible embodiment, a retaining ring 21 may be used instead, in which a plurality of thin sheets made of the same material as the wafer are arranged along the circumference on a ring-shaped component made of resin.

[0073] Figure 5 and Figure 6 The above-mentioned retaining ring 21 is shown in FIG. Figure 5 This is a plan view of the retaining ring 21 as viewed from the side in contact with the polishing pad 16 of the polishing plate 14 . Figure 6 This is a side view of the retaining ring 21 as seen from the side.

[0074] The retaining ring 21 is composed of an annular member 22 made of resin and a plurality of thin sheets 23. The material of the thin sheets 23 is the same as that of the wafer, and in this embodiment, the material of the thin sheets 23 is silicon. The thin sheets 23 are arranged on the annular member 22 along the circumference. The present application does not limit the method of fixing the thin sheets 23 on the annular member 22, and any fixing method may be used.

[0075] When the retaining ring 21 of the present embodiment is used in the grinding device 1, since the thin sheet 23 made of silicon material of the same material as the wafer to be ground is fixed on the surface of the retaining ring 21 used in contact with the polishing pad 16, the temperature difference between the portion where the surface of the polishing pad contacts the surface of the retaining ring and the portion where the surface of the polishing pad contacts the surface of the wafer can be eliminated. In addition, the thickness of the retaining ring can be controlled to an optimal value relative to the thickness of the wafer, that is, there can be no height difference between the retaining ring and the wafer on the polishing pad in the thickness direction. In addition, due to these effects, the present embodiment can provide a retaining ring that can reduce the influence on the overall flatness of the wafer and can suppress the collapse of the edge of the wafer.

[0076] Furthermore, if the portion of the retaining ring that contacts the grinding surface 16 is formed into a thin sheet, only the portion of the retaining ring that is worn out during the grinding process can be replaced, thereby improving convenience.

[0077] In this embodiment, the material of the wafer is silicon, but the present application is not limited thereto when implemented, and the material of the wafer may also be silicon (Si), silicon carbide (SiC), gallium nitride (GaN), gallium arsenide (GaAs), etc. Therefore, the material of the thin sheet used in the retaining ring is not limited to silicon, as long as it is the same as the material of the wafer to be polished, that is, it may also be silicon carbide (SiC), gallium nitride (GaN), gallium arsenide (GaAs), etc.

[0078] In a second aspect, the present application further provides a grinding head mechanism, which includes a grinding head and a retaining ring according to the first aspect installed on the grinding head.

[0079] In a third aspect, the present application further provides a grinding device, which includes a polishing plate mechanism and the grinding head mechanism in the second aspect arranged above the polishing plate mechanism.

[0080] By using a retaining ring having at least a surface in contact with the polishing pad and a material of the same material as that of the wafer to be polished, the temperature difference between the portion in contact with the retaining ring surface and the portion in contact with the wafer surface on the polishing pad surface can be eliminated. In addition, the thickness of the retaining ring can be controlled to an optimal value relative to the thickness of the wafer. As a result, a polishing head mechanism and a polishing device are provided that can improve the overall flatness of the wafer and suppress edge collapse.

[0081] The present application is described in sufficient detail above with certain particularity. It should be understood by those skilled in the art that the description in the embodiments is merely exemplary, and all changes made without departing from the true spirit and scope of the present application should fall within the scope of protection of the present application. The scope of protection claimed in the present application is defined by the claims, rather than by the above description in the embodiments.

Claims

1. A retaining ring, characterized in that: The retaining ring is used in a wafer grinding device, and the material of at least the surface of the retaining ring in contact with the polishing pad is the same as the material of the wafer to be ground, wherein: The retaining ring is in the shape of an annular ring and the material of the entire retaining ring is the same as the material of the chip. The thickness of the retaining ring is equal to or greater than the thickness of the chip to be ground. Alternatively, the retaining ring includes an annular component made of resin and a contact layer made of the same material as the chip, and the contact layer is arranged on the lower surface of the annular component.

2. The retaining ring according to claim 1, characterized in that The retaining ring is provided with a slit for supplying slurry to the polishing surface of the wafer.

3. The retaining ring according to claim 1, characterized in that The thickness of the contact layer is equal to or greater than the thickness of the wafer to be ground.

4. The retaining ring according to claim 1, characterized in that The contact layer is annular and is provided with a gap for supplying slurry to the grinding surface of the wafer.

5. The retaining ring according to claim 1, wherein: The contact layer includes a plurality of thin sheets arranged on the annular member along a circumference and made of the same material as the wafer.

6. The retaining ring according to any one of claims 1 to 5, characterized in that: The material of at least the surface of the retaining ring in contact with the polishing pad is any one of silicon, silicon carbide, gallium nitride and gallium arsenide.

7. A grinding head mechanism, characterized in that: The grinding head mechanism comprises a grinding head and a retaining ring as claimed in any one of claims 1 to 6 mounted on the grinding head.

8. A grinding device, characterized in that: The grinding device comprises a polishing plate mechanism and a grinding head mechanism as claimed in claim 7 which is arranged above the polishing plate mechanism.

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