Grinding head with diameter larger than that of wafer

Abstract

The utility model discloses a grinding head with the diameter larger than that of a wafer, which comprises a swing arm and a grinding head, the diameter of the grinding head is larger than that of the wafer, a liquid conveying device is arranged on the swing arm or in the swing arm, the liquid conveying device is communicated with the grinding head, and a plurality of liquid guide grooves are arranged at the bottom of the grinding head. Through the design of the structure, the grinding head (the diameter of the grinding head is larger than that of a wafer) with the size of a super wafer is adopted, and the defect that an unfinished area exists is overcome. As shown in Figure 1, the use area of the wafer is always located in the finishing range of the grinding head, and when the diameter of the grinding head reaches 1.2-1.5 times of the diameter of the wafer, the 100% finishing coverage rate of the surface (the use area of the wafer) of the grinding pad can be guaranteed no matter how the swing amplitude and the swing frequency are adjusted, and the periodic non-finishing area is completely eliminated. Cleaning or polishing liquid is continuously conveyed to the grinding head through the liquid conveying device, and liquid is continuously supplied to the contact surface of the grinding head and the grinding pad and the area outside the contact surface for washing, so that residual pollutants are removed.

Description

Technical Field

[0001] This utility model relates to the field of CMP platform grinding head technology, and more specifically, to a grinding head with a diameter larger than that of a wafer. Background Technology

[0002] Chemical mechanical polishing (CMP) is a core process determining wafer surface flatness. Existing dressers are limited in function, only able to fix the grinding head. Because the diameter of the grinding head is only 60%-80% of the wafer size, this dimensional mismatch causes periodic un-shaving areas to form on the polishing pad surface during the dresser's reciprocating oscillation. These un-shaving areas directly cause micro-defects on the wafer surface, posing a fatal threat to the yield of processes below 28 nanometers, and also accumulate contaminants. These residual contaminants mainly fall into three categories:

[0003] 1. Residual diamond abrasive particles: Hard particles with a diameter >5μm can embed into the wafer surface under polishing pressure, forming micron-level scratches, leading to localized open circuits in integrated circuits;

[0004] 2. Polyurethane debris accumulation: Non-homogeneous debris falling off the surface of the grinding pad will change the local friction coefficient, causing dynamic pressure fluctuations to exceed the design value and inducing indentation defects;

[0005] 3. Metal ion contamination: Mechanically exfoliated products from wafer surface materials (such as Cu). 2+ Al 3+ This can cause electrochemical corrosion.

[0006] In summary, existing dressing devices not only create un-dressed areas and accumulate contaminants, but also have very low contaminant removal efficiency, with an average residue rate of 39.5% for the three types of contaminants. Therefore, how to solve the problem of periodically un-dressed areas on the surface of the grinding pad and how to efficiently remove the above three types of contaminants are the core technical problems to be solved by this utility model. Utility Model Content

[0007] The utility model description section introduces a series of simplified concepts, which will be further explained in detail in the detailed description section. This utility model description section is not intended to limit the key features and essential technical features of the claimed technical solution, nor is it intended to determine the scope of protection of the claimed technical solution.

[0008] To at least partially solve the above problems, this utility model provides a grinding head with a diameter larger than that of a wafer, comprising: a swing arm and a grinding head, one end of the swing arm being connected to a driving device and the other end being movably connected to the grinding head, the diameter of the grinding head being larger than that of the wafer, a liquid infusion device being provided on or inside the swing arm, the liquid infusion device being in communication with the grinding head, and a plurality of liquid guiding grooves being provided at the bottom of the grinding head.

[0009] Preferably, one end of the infusion device is connected to the infusion supply equipment, and the other end is connected to the grinding head.

[0010] Preferably, the grinding head is provided with a liquid outlet pipe that penetrates the grinding head. The outer wall of the liquid outlet pipe is movably connected to the grinding head through a rotating component. The grinding head rotates around the liquid outlet pipe as a rotation axis. The top of the liquid outlet pipe is connected to a swing arm and communicates with the infusion device. The bottom of the liquid outlet pipe penetrates the grinding head.

[0011] Preferably, the swing arm is provided with a power device for driving the grinding head to rotate. The power device is connected to a second transmission component on the grinding head through a first transmission component. The second transmission component is sleeved on the outer wall of the liquid outlet pipe through a rotating component.

[0012] Preferably, the bottom of the grinding head is provided with a liquid-containing area, which is a recess extending upward from the bottom surface of the grinding head, and the bottom of the liquid outlet pipe is located on the top surface of the liquid-containing area.

[0013] Preferably, the liquid-containing area is a frustum shape, smaller at the top and larger at the bottom.

[0014] Preferably, the inlet end of the liquid guide groove is connected to the liquid holding area, and the outlet end of the liquid guide groove is located on the side wall of the grinding head.

[0015] Preferably, the liquid guiding groove is arranged in a radial spiral shape centered on the rotation axis of the grinding head.

[0016] Preferably, the bottom of the liquid-containing zone has a large diameter. The top is a small path ,in The height of the liquid zone

[0017] ,

[0018] in The entry angle of the liquid in the liquid-containing area into the liquid guiding tank. .

[0019] Preferably, the number of liquid guiding channels is at least 6.

[0020] Compared with the prior art, the present invention has at least the following beneficial effects:

[0021] By designing the above structure and using a super-wafer-sized grinding head (grind head diameter larger than wafer diameter), defects such as untrimmed areas are eliminated. Figure 1 As shown, the wafer's working area is always within the dressing range of the grinding head. When the grinding head diameter reaches 1.2-1.5 times the wafer diameter, regardless of how the swing amplitude and oscillation frequency are adjusted, the surface of the grinding pad (the wafer's working area) can achieve 100% dressing coverage, completely eliminating periodically undressed areas.

[0022] In addition, cleaning or polishing liquid is continuously supplied to the grinding head through an infusion device (infusion channel or external infusion device), and liquid is continuously supplied to the contact surface between the grinding head and the polishing pad and the area outside the contact surface through the liquid guide groove set at the bottom of the grinding head to remove residual contaminants.

[0023] The grinding head of this invention has a diameter larger than that of the wafer. Other advantages, objectives and features of this invention will be partly apparent from the following description, and partly understood by those skilled in the art through study and practice of this invention. Attached Figure Description

[0024] The accompanying drawings are provided to further illustrate the present invention and form part of the specification. They are used together with the embodiments of the present invention to explain the present invention, but do not constitute a limitation thereof. In the drawings:

[0025] Figure 1 This is a schematic diagram of the area to be used on a wafer and a grinding head for super-wafer size.

[0026] Figure 2 These are top views of two different types of infusion devices (A is located inside the swing arm, and B is located on the swing arm).

[0027] Figure 3 The images show cross-sectional views of two different types of infusion devices (A is the infusion channel, and B is the external infusion device).

[0028] In the diagram: 1 swing arm, 2 grinding head, 3 wafer, 4 liquid guide tank, 51 infusion channel, 52 external infusion device, 6 outlet pipe, 7 rotating component, 8 power device, 9 first transmission component, 10 second transmission component. Detailed Implementation

[0029] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments, so that those skilled in the art can implement it based on the description.

[0030] It should be understood that terms such as “having,” “comprising,” and “including” as used herein do not exclude the presence or addition of one or more other elements or combinations thereof.

[0031] As shown in the figure, this utility model provides a grinding head with a diameter larger than that of a wafer, comprising: a swing arm 1 and a grinding head 2. One end of the swing arm 1 is connected to a driving device, and the other end is movably connected to the grinding head 2. The driving device is a commercially available product or existing technology, used to drive the swing arm 1 to swing the grinding head 2. The diameter of the grinding head 2 is larger than that of the wafer 3, thereby enabling the wafer 1 to be trimmed on the polishing pad regardless of how the swing amplitude and oscillation frequency of the grinding head 2 are adjusted, without the existence of untrimmed areas as in the prior art. Furthermore, in order to effectively remove residual contaminants on the polishing pad, an infusion device is provided on or inside the swing arm 1. When the infusion device is located inside the swing arm 1, it is located inside the swing arm 1 in the form of an infusion channel 51; when the infusion device is located on the swing arm 1, it exists as an accessory of the swing arm 1 in the form of an external infusion device 52. The infusion device is connected to the grinding head 2. The bottom of the grinding head 2 is provided with several liquid guiding grooves 4. The liquid delivered by the infusion device can be delivered to the grinding head 2 for the grinding head 2 to trim the grinding pad. At the same time, the liquid can flow out of the grinding head 2 from the liquid guiding grooves 4, thereby flushing the trimmed and untrimmed areas and removing residual contaminants.

[0032] By designing the above structure and using a grinding head 2 of superwafer 3 size (the diameter of grinding head 2 is larger than the diameter of wafer 3), the defect of having untrimmed areas is eliminated. For example... Figure 1 As shown, the working area of ​​wafer 3 is always within the dressing range of grinding head 2. When the diameter of grinding head 2 reaches 1.2-1.5 times the diameter of wafer 3, no matter how the swing amplitude and oscillation frequency are adjusted, the surface of the grinding pad (the working area of ​​wafer 3) can be guaranteed to achieve 100% dressing coverage, completely eliminating the periodically undressed area.

[0033] In addition, cleaning or polishing liquid is continuously supplied to the grinding head 2 through the infusion device (infusion channel 51 or external infusion device 52), and the liquid is continuously supplied to the contact surface between the grinding head 2 and the polishing pad and the area outside the contact surface through the liquid guide groove 4 provided at the bottom of the grinding head 2 to remove residual contaminants.

[0034] One end of the infusion device is connected to the liquid supply equipment, and the other end is connected to the grinding head 2, so that polishing or cleaning liquid can be delivered to the grinding head 2.

[0035] As one of many implementations, the grinding head 2 is provided with a liquid outlet pipe 6 that penetrates the grinding head 2. The outer wall of the liquid outlet pipe 6 is movably connected to the grinding head 2 through a rotating component 7, which can be a bearing or a bushing, so that the grinding head 2 can rotate around the liquid outlet pipe 6 as a rotation axis. The top of the liquid outlet pipe 6 is connected to the swing arm 1 and communicates with the liquid delivery device. The liquid outlet pipe 6 is connected to the swing arm 1, so that the swing arm 1 can drive the grinding head 2 to swing through the liquid outlet pipe 6. The bottom of the liquid outlet pipe 6 penetrates the grinding head 2, so that the cleaning or polishing liquid can diffuse from the center of the grinding head 2 to the surrounding area, so that the liquid can cover the contact surface between the grinding head 2 and the polishing pad.

[0036] The bottom of the grinding head 2 is provided with a liquid-receiving area, which is a recess extending upward from the bottom surface of the grinding head 2. The bottom of the liquid outlet pipe 6 is located on the top surface of the liquid-receiving area. Liquid can be sprayed directly onto the grinding pad from the outlet end of the liquid outlet pipe 6. The liquid-receiving area prevents liquid splashing. The liquid-receiving area is a frustum shape, smaller at the top and larger at the bottom. The inlet end of the liquid guide groove 4 is connected to the liquid-receiving area, and the outlet end of the liquid guide groove 4 is located on the side wall of the grinding head 2.

[0037] Because the grinding head 2 is not equipped with a power device 8 for its rotation in this embodiment, in order for the grinding head 2 to rotate during the grinding process, the liquid guide groove 4 is arranged in a radial spiral shape centered on the rotation axis of the grinding head 2. To generate sufficient torque to drive the grinding head 2 to rotate when the liquid leaves the grinding head 2 from the liquid guide groove 4, the spiral angle of the liquid guide groove 4 is... The angle between the tangential and radial directions is between 60° and 75°.

[0038] The bottom of the liquid-containing zone is a large diameter The top is a small path ,in The height of the liquid zone

[0039] ,

[0040] in The entry angle of the liquid into the liquid guide groove 4 within the liquid-containing area is typically 30° to 60°. The number of liquid guide grooves 4 is at least six, ensuring that the liquid ejected from the liquid guide grooves 4 can evenly cover the contact area between the grinding head 2 and the grinding pad, as well as the non-contact areas. The large diameter of the liquid-containing area... It is 1 / 3 of the radius of the grinding head 2, which can ensure uniform liquid distribution.

[0041] In order to ensure that the grinding head 2 can still rotate without the power unit 8, the driving torque generated by the liquid sprayed from the liquid guide groove 4 needs to be greater than the friction torque between the rotating part 7 (e.g., bearing) and the grinding head 2 when the grinding head 2 rotates.

[0042] Furthermore, such as Figure 3 As shown, the swing arm 1 is equipped with a power device 8 for driving the grinding head 2 to rotate. The power device 8 can be an electric motor. The power device 8 is connected to a second transmission component 10 on the grinding head 2 via a first transmission component 9. The second transmission component 10 is sleeved on the outer wall of the liquid outlet pipe 6 via a rotating component 7. Both the first transmission component 9 and the second transmission component 10 are gears, and the rotating component 7 can be a bearing or a bushing. Thus, the power device 8 can drive the second transmission component 10 to rotate via the first transmission component 9, and the second transmission component 10 can drive the grinding head 2 to rotate around the liquid outlet pipe 6 as its rotation axis. By setting up the power device 8, the issue of driving torque is eliminated. However, a liquid receiving area and a liquid guiding groove 4 can still be set up to ensure sufficient liquid supply. Because the driving torque is not considered, the liquid can flow out at a low speed from the liquid outlet end of the liquid guiding groove 4, thereby effectively avoiding liquid splashing.

[0043] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0044] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0045] Although the embodiments of this utility model have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for this utility model. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, this utility model is not limited to the specific details and the illustrations shown and described herein.

Claims

1. A polishing head having a diameter greater than a diameter of a wafer, comprising: The arm (1) and the grinding head (2), one end of the arm (1) is connected with the driving device, the other end is movably connected with the grinding head (2), characterized in that the diameter of the grinding head (2) is larger than the diameter of the wafer (3), the arm (1) is provided with a liquid feeding device, the liquid feeding device is communicated with the grinding head (2), the bottom of the grinding head (2) is provided with a plurality of liquid guide grooves (4).

2. The lapping head having a diameter larger than a wafer diameter according to claim 1, wherein, One end of the liquid feeding device is communicated with the liquid supply device, and the other end is communicated with the grinding head (2).

3. The lapping head having a diameter larger than a wafer diameter according to claim 1, wherein, The grinding head (2) is provided with a liquid outlet pipe (6) penetrating the grinding head (2), the outer wall of the liquid outlet pipe (6) is movably connected with the grinding head (2) through a rotating piece (7), the grinding head (2) rotates around the liquid outlet pipe (6) as the rotating shaft, the top of the liquid outlet pipe (6) is connected with the arm (1) and communicated with the liquid feeding device, the bottom of the liquid outlet pipe (6) penetrates the grinding head (2).

4. The lapping head having a diameter larger than a wafer diameter according to claim 3, wherein, The arm (1) is provided with a power device (8) for driving the grinding head (2) to rotate, the power device (8) is connected with a second transmission piece (10) on the grinding head (2) through a first transmission piece (9), and the second transmission piece (10) is sleeved on the outer wall of the liquid outlet pipe (6) through the rotating piece (7).

5. The lapping head having a diameter larger than a wafer diameter according to claim 3, wherein, The bottom of the grinding head (2) is provided with a liquid containing area, the liquid containing area is a concave extending upward from the bottom surface of the grinding head (2), and the bottom of the liquid outlet pipe (6) is located on the top surface of the liquid containing area.

6. The lapping head having a diameter larger than a wafer diameter according to claim 5, wherein, The liquid containing area is a circular truncated cone with small top and large bottom.

7. The lapping head having a diameter larger than a wafer diameter according to claim 5, wherein, The liquid inlet end of the liquid guide groove (4) is communicated with the liquid containing area, and the liquid outlet end of the liquid guide groove (4) is located on the side wall of the grinding head (2).

8. The lapping head having a diameter larger than a wafer diameter according to claim 7, wherein, The liquid guide groove (4) is radially spiral around the rotating shaft of the grinding head (2).

9. The lapping head having a diameter larger than a wafer diameter according to claim 6, wherein, The bottom of the liquid-containing area is large in diameter The top of the liquid-containing area is small in diameter Wherein The height of the liquid-containing area ， wherein is the angle of entry of the liquid in the liquid containment zone into the liquid guide channel (4), .

10. The lapping head having a diameter larger than a wafer diameter according to claim 1, wherein, The number of the liquid guide grooves (4) is at least 6.

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