Detection windows, polishing pads, and chemical mechanical polishing apparatus

Abstract

The application provides a detection window, a grinding gasket and a chemical mechanical grinding device. Two ends of an inner frame of the detection window are arc-shaped, and a top opening of the inner frame is larger than a bottom opening of the inner frame, so that the side wall of the inner frame gradually converges inward at a preset inclined angle to form a slope structure. The detection window, the grinding gasket and the chemical mechanical grinding device provided by the application can disperse the stress on the two ends of the inner frame by setting the two ends of the inner frame as arc-shaped, so as to weaken the bulging deformation of the detection window caused by the pressure difference and the lateral friction force. The side wall of the inner frame gradually converges inward at a preset inclined angle to form a slope structure by setting the top opening of the inner frame as larger than the bottom opening of the inner frame, so that a certain lateral deformation space is provided to relieve the longitudinal deformation when the detection window is subjected to the lateral friction force, so as to weaken the degree of bulging, and further to reduce the risk of the detection window being broken.

Description

Technical Field

[0001] This invention relates to the field of semiconductor manufacturing technology, and in particular to a detection window, a polishing pad, and a chemical mechanical polishing apparatus. Background Technology

[0002] Chemical Mechanical Polishing (CMP) is currently the only ultra-precision machining technology in semiconductor and microelectromechanical system (MEMS) processing and packaging that can achieve nanometer-level global planarization. CMP is not only an enabling process for advanced photolithography and copper interconnect technologies, but also a critical step in the manufacturing of integrated circuits such as chips. It has a significant impact on chip performance and power consumption, making it an indispensable process for achieving advanced manufacturing processes.

[0003] Please see Figure 1 and Figure 2 , Figure 1 This is a schematic diagram of a chemical mechanical grinding device in the prior art; Figure 2 for Figure 1 A schematic diagram showing the structure on which a monitoring window is mounted on the grinding pad. From... Figure 1 and Figure 2 As can be seen, the chemical mechanical polishing (CMP) equipment includes a polishing table 10, a polishing pad 11 disposed on the polishing table 10, and a polishing head 13 disposed above the polishing pad 11; the polishing pad 11 is equipped with a monitoring window 12 for monitoring the polishing status of the wafer 14. When the wafer 14 is subjected to CMP polishing, the back side of the wafer 14 is adsorbed onto the bottom of the polishing head 13, and the front side of the wafer 14 is in contact with the polishing pad 11. The CMP equipment achieves wafer surface planarization through a combination of chemical etching and mechanical polishing.

[0004] However, during the grinding of wafer 14, occasional holes may appear in the monitoring window 12. If grinding of wafer 14 continues after holes appear in the monitoring window 12, it will affect the machine's process parameters and wafer morphology, making it impossible to meet the thickness control and planarization requirements of the CMP process, which will bring high risks to subsequent processes and wafer yield. Summary of the Invention

[0005] The purpose of this invention is to provide a detection window, a polishing pad, and a chemical mechanical polishing apparatus to solve one or more problems in the prior art, such as the occasional occurrence of holes in the monitoring window affecting the acquisition of process parameters and the morphology of the wafer.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solution: a detection window is disposed in a grinding pad, the two ends of the inner frame of the detection window are both arc-shaped, and the top opening of the inner frame is larger than the bottom opening of the inner frame, so that the side wall of the inner frame gradually converges inward at a preset tilt angle to form a slope structure.

[0007] Optionally, the orthographic projection of the inner frame onto the plane of the grinding pad is a racetrack ring.

[0008] Optionally, the orthographic projection of the inner frame onto the plane of the abrasive pad is an elliptical ring.

[0009] Optionally, the orthographic projection of the top of the inner frame onto the plane where the grinding pad is located and the orthographic projection of the bottom of the inner frame onto the plane where the grinding pad is located are concentric.

[0010] Optionally, the preset tilt angle can range from 15 degrees to 30 degrees.

[0011] Optionally, the detection window is made of a light-transmitting material.

[0012] To achieve the above objectives, the present invention also provides an abrasive pad, wherein the abrasive pad is provided with the detection window described in any of the above claims.

[0013] Optionally, the upper surface of the abrasive pad and the upper surface of the detection window are coplanar.

[0014] Optionally, the abrasive pad may have at least two detection windows.

[0015] To achieve the above objectives, the present invention also provides a chemical mechanical polishing apparatus, including the detection window or the polishing pad described in any of the above claims.

[0016] Compared with the prior art, the detection window, grinding pad, and chemical mechanical polishing apparatus provided by the present invention have the following beneficial effects:

[0017] The detection window provided by this invention is disposed in a grinding pad. Both ends of the inner frame of the detection window are arc-shaped, and the top opening of the inner frame is larger than the bottom opening, so that the sidewalls of the inner frame gradually converge inward at a predetermined angle to form a sloping structure. Therefore, the detection window provided by this invention, by setting both ends of the inner frame to be arc-shaped, allows the stress on both ends of the inner frame to be dispersed, thereby reducing the bulging deformation of the detection window caused by pressure difference and lateral friction. Furthermore, by setting the top opening of the inner frame to be larger than the bottom opening, allowing the sidewalls of the inner frame to gradually converge inward at a predetermined angle to form a sloping structure, a certain amount of lateral deformation space is provided when the detection window is subjected to lateral friction to reduce longitudinal deformation, thereby reducing the degree of bulging and thus reducing the risk of the detection window breaking.

[0018] Since the abrasive pad and the chemical mechanical polishing device provided by this invention belong to the same inventive concept as the detection window provided by this invention, the abrasive pad and the chemical mechanical polishing device provided by this invention have at least all the advantages of the detection window provided by this invention. For the advantages of the abrasive pad and the chemical mechanical polishing device provided by this invention, please refer to the relevant description of the beneficial effects of the detection window provided by this invention, which will not be repeated here. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of a chemical mechanical grinding device in the prior art;

[0020] Figure 2 for Figure 1 The diagram shows a structure with a monitoring window mounted on the grinding pad.

[0021] Figure 3 This is a schematic diagram of the structure of a monitoring window in the prior art;

[0022] Figure 4 for Figure 3 A side view of the monitoring window shown;

[0023] Figure 5 for Figure 3 The image shown is a specific example of a monitoring window bulging under stress.

[0024] Figure 6 This is a specific example diagram of a detection window provided in Embodiment 1 of the present invention;

[0025] Figure 7 for Figure 6 A side-view diagram of the detection window shown;

[0026] Figure 8This is another specific example diagram of a detection window provided in Embodiment 1 of the present invention;

[0027] Figure 9 for Figure 8 A side-view diagram of the detection window shown;

[0028] The annotations in the attached figures are explained as follows:

[0029] 10-Grinding table, 11-Grinding pad, 12-Monitoring window, 121-Inner liner, 13-Grinding head, 14-Wafer, 20-Detection window, 201-Inner frame. Detailed Implementation

[0030] The detection window, grinding pad, and chemical mechanical polishing apparatus proposed in this invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. The advantages and features of this invention will become clearer from the following description. It should be noted that the drawings are all in a very simplified form and use non-precise proportions, only used to facilitate and clarify the illustration of the embodiments of this invention. Please refer to the drawings to make the objectives, features, and advantages of this invention more apparent and understandable. It should be understood that the structures, proportions, sizes, etc., depicted in the accompanying drawings are only used to complement the content disclosed in the specification, for those skilled in the art to understand and read, and are not intended to limit the implementation conditions of this invention. Any modifications to the structure, changes in proportions, or adjustments to the size, if they are the same as or similar to the effects and objectives achieved by this invention, should still fall within the scope of the technical content disclosed in this invention. Specific design features of the invention disclosed herein, including, for example, specific dimensions, orientations, positions, and shapes, will be determined in part by the specific application and usage environment. Furthermore, in the embodiments described below, sometimes the same reference numerals are used together across different drawings to indicate the same parts or parts having the same function, and repeated descriptions are omitted.

[0031] To better understand and explain the present invention, before describing the specific implementation of the detection window, grinding pad, and chemical mechanical polishing apparatus provided by the present invention, the research process for proposing the present invention will be briefly described as follows.

[0032] Please continue reading Figure 1 and Figure 2First, the inventors of this invention analyzed the reasons for the occasional hole phenomenon in the monitoring window 12. By observing the grinding process of the wafer 14, the inventors found that the monitoring window 12 is continuously subjected to lateral friction and compression forces during the grinding process. Friction generates heat, and the space below the monitoring window 12 is a closed space, causing the gas inside the monitoring window 12 to expand due to heat, creating a pressure difference between the inside and outside, thereby generating an outward bulging force. As the grinding pad 11 is consumed and becomes thinner, at the end of the consumable life cycle of the grinding pad 11, the monitoring window 12 will experience occasional hole phenomena under the combined action of friction, compression, and the outward bulging force generated inside the monitoring window 12.

[0033] To solve this problem, the inventors first considered cooling the monitoring window 12. However, considering that the grinding table 10 already has integrated cooling water pipes for physical cooling of the grinding pad 11, adding a separate circulating air cooling system to the monitoring window 12 would increase design, purchase, usage, and maintenance costs. Next, the inventors considered finding a grinding pad 11 made of superior wear-resistant material, but this would increase testing and inspection costs.

[0034] Further, please see Figures 3 to 5 , Figure 3 This is a schematic diagram of the structure of a monitoring window in the prior art; Figure 4 for Figure 3 A side view of the monitoring window shown; Figure 5 for Figure 3 The image shown is a specific example of a monitoring window bulging under stress. From Figures 3 to 5 As can be seen, the inner lining 121 of the monitoring window 12 is rectangular. After extensive research and continuous in-depth practice, the inventors discovered that the four corners of the rectangular inner lining 121 are prone to concentrated stress, which can easily cause the monitoring window 12 to bulge and develop holes due to stress.

[0035] After optimization and improvement, for example, designing the inner lining 121 of the monitoring window 12 as an elliptical or rounded rectangle structure on the outer edge, the pressure can be evenly distributed on each point of the arc, which can effectively reduce the risk of window breakage.

[0036] Based on the above research, the core idea of ​​this invention is to solve the technical problems in the prior art, such as the occasional hole phenomenon in the monitoring window affecting the acquisition of machine process parameters and wafer morphology.

[0037] To achieve the above-mentioned goals, the present invention provides a detection window, a polishing pad, and a chemical mechanical polishing apparatus. By optimizing the structure of the monitoring window, the present invention solves one or more problems, such as the occasional occurrence of holes in the existing monitoring window, which affects the acquisition of process parameters and wafer morphology.

[0038] The specific embodiments of the detection window, grinding pad, and chemical mechanical polishing apparatus provided by the present invention will be described in detail below.

[0039] Example 1

[0040] This embodiment provides a detection window, which is set in the abrasive pad (not shown in the figure). For details, please refer to... Figure 6 and Figure 7 , Figure 6 This is a specific example diagram of the detection window provided in this embodiment;

[0041] Figure 7 for Figure 6 A side-view diagram of the detection window is shown. From Figure 6 and Figure 7 As can be seen, both ends of the inner frame 201 of the detection window 20 are arc-shaped, and the top opening of the inner frame 201 is larger than the bottom opening, so that the sidewalls of the inner frame 201 gradually converge inward at a preset inclination angle to form a sloping structure. Therefore, the detection window provided in this embodiment, by setting both ends of the inner frame 201 to be arc-shaped, allows the stress on both ends of the inner frame 201 to be dispersed, thereby reducing the bulging deformation of the detection window 20 due to pressure difference and lateral friction. Furthermore, by setting the top opening of the inner frame 201 to be larger than the bottom opening, so that the sidewalls of the inner frame 201 gradually converge inward at a preset inclination angle to form a sloping structure, a certain lateral deformation space can be provided to reduce longitudinal deformation when the detection window 20 is subjected to lateral friction, thereby reducing the degree of bulging and thus reducing the risk of the detection window 20 breaking.

[0042] Please continue reading Figure 6 and Figure 7 For example, in some exemplary embodiments, the orthographic projection of the inner frame 201 onto the plane where the abrasive pad is located is a racetrack ring.

[0043] It should be noted that, as those skilled in the art will understand, the above is merely an exemplary description of the inner frame 201 and not a limitation thereof.

[0044] For example, please see Figure 8 and Figure 9 , Figure 8 Another specific example diagram of the detection window provided in this embodiment; Figure 9 for Figure 8 A side-view diagram of the detection window is shown. From Figure 8 and Figure 9It can be seen that in some other embodiments, the orthographic projection of the inner frame 201 onto the plane where the grinding pad is located can also be an elliptical ring.

[0045] For the preferred options, please continue reading. Figures 6 to 9 ,like Figures 6 to 9 As shown, the orthographic projection of the top of the inner frame 201 onto the plane where the grinding pad is located and the orthographic projection of the bottom of the inner frame 201 onto the plane where the grinding pad is located are at the same center.

[0046] It should be noted that the present invention does not impose excessive limitations on the specific value of the preset tilt angle, and the specific value of the preset tilt angle can be set according to the actual application scenario. For example, in some embodiments, the value range of the preset tilt angle includes 15 degrees to 30 degrees; in other embodiments, the preset tilt angle can also be 45 degrees; and in still other embodiments, the preset tilt angle can also be 60 degrees.

[0047] Preferably, the detection window 20 is made of a light-transmitting material. This allows for real-time monitoring of the surface condition of the wafer 14, enabling precise determination of the grinding endpoint and contributing to improved production efficiency and product quality.

[0048] Example 2

[0049] This embodiment provides a grinding pad, wherein the grinding pad is provided with the detection window 20 described in any of the above embodiments.

[0050] Since the grinding pad provided in this embodiment belongs to the same inventive concept as the detection window 20 provided in any of the above embodiments, the grinding pad provided in this embodiment has at least all the advantages of the detection window 20 provided in the above embodiments. For the advantages of the grinding pad provided in this embodiment, please refer to the relevant description of the beneficial effects of the detection window 20 provided in the above embodiments, which will not be repeated here.

[0051] Preferably, the upper surface of the grinding pad and the upper surface of the detection window 20 are coplanar. Therefore, by making the grinding pad and the upper surface of the detection window 20 coplanar, uniform pressure can be applied throughout the grinding area, thereby improving the quality and consistency of the grinding process.

[0052] Furthermore, the polishing pad is provided with at least two of the aforementioned detection windows 20. Therefore, by providing multiple detection windows 20 in the polishing pad, the state of the wafer 14 can be monitored simultaneously at different locations, which helps to provide a more comprehensive understanding of the material removal status of the entire wafer 14 surface, thereby improving the accuracy and reliability of the detection results.

[0053] Example 3

[0054] This embodiment provides a chemical mechanical polishing apparatus, including the detection window 20 described in any of the above embodiments or the polishing pad described in any of the above embodiments.

[0055] Since the chemical mechanical polishing apparatus provided in this embodiment belongs to the same inventive concept as the detection window 20 or the polishing pad provided in any of the above embodiments, the chemical mechanical polishing apparatus provided in this embodiment has at least all the advantages of the detection window 20 or the polishing pad provided in the above embodiments. For the advantages of the chemical mechanical polishing apparatus provided in this embodiment, please refer to the relevant description of the beneficial effects of the detection window 20 or the polishing pad provided in the above embodiments, which will not be repeated here.

[0056] In summary, the detection window, abrasive pad, and chemical mechanical polishing apparatus provided by this invention have the following advantages: The detection window provided by this invention is disposed in the abrasive pad, and both ends of the inner frame of the detection window are arc-shaped, with the top opening of the inner frame being larger than the bottom opening, so that the sidewalls of the inner frame gradually converge inward at a preset inclination angle to form a sloping structure. Therefore, the detection window provided by this invention, by setting both ends of the inner frame to be arc-shaped, allows the stress on both ends of the inner frame to be dispersed, thereby reducing the bulging deformation of the detection window caused by pressure difference and lateral friction. Furthermore, by setting the top opening of the inner frame to be larger than the bottom opening of the inner frame, allowing the sidewalls of the inner frame to gradually converge inward at a preset inclination angle to form a sloping structure, a certain lateral deformation space can be provided when the detection window is subjected to lateral friction to reduce longitudinal deformation, thereby reducing the degree of bulging and thus reducing the risk of the detection window breaking.

[0057] Since the abrasive pad and the chemical mechanical polishing device provided by this invention belong to the same inventive concept as the detection window provided by this invention, the abrasive pad and the chemical mechanical polishing device provided by this invention have at least all the advantages of the detection window provided by this invention. For the advantages of the abrasive pad and the chemical mechanical polishing device provided by this invention, please refer to the relevant description of the beneficial effects of the detection window provided by this invention, which will not be repeated here.

[0058] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.

Claims

1. A detection window disposed in an abrasive pad, characterized in that, Both ends of the inner frame of the detection window are arc-shaped, and the top opening of the inner frame is larger than the bottom opening of the inner frame, so that the sidewalls of the inner frame gradually converge inward at a preset tilt angle to form a sloping structure.

2. The detection window as described in claim 1, characterized in that, The inner frame, when projected onto the plane of the grinding pad, forms a racetrack-shaped ring.

3. The detection window as described in claim 1, characterized in that, The inner frame's orthographic projection onto the plane of the grinding pad is an elliptical ring.

4. The detection window as described in claim 1, characterized in that, The orthographic projection of the top of the inner frame onto the plane where the grinding pad is located and the orthographic projection of the bottom of the inner frame onto the plane where the grinding pad is located are at the same center.

5. The detection window as described in claim 1, characterized in that, The preset tilt angle ranges from 15 degrees to 30 degrees.

6. The detection window as described in claim 1, characterized in that, The detection window is made of a light-transmitting material.

7. An abrasive pad, characterized in that, The abrasive pad is provided with a detection window as described in any one of claims 1 to 6.

8. The grinding pad as described in claim 7, characterized in that, The upper surface of the abrasive pad and the upper surface of the detection window are coplanar.

9. The grinding pad as described in claim 7, characterized in that, The abrasive pad is provided with at least two detection windows.

10. A chemical mechanical grinding apparatus, characterized in that, It includes the detection window as described in any one of claims 1 to 6 or the abrasive pad as described in any one of claims 7 to 9.

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