Polishing pad and polishing equipment

Abstract

The invention provides a polishing pad and polishing equipment. Relates to the technical field of semiconductor manufacturing. The polishing pad comprises a first polishing part and a second polishing part, and the polishing degrees of the first polishing part and the second polishing part on a corresponding to-be-polished area on a wafer are different.

Description

Technical Field

[0001] The present disclosure relates to the field of semiconductor manufacturing technology, and in particular to a polishing pad and a polishing device. Background Art

[0002] In the field of semiconductor manufacturing, polishing technology is the key technology to achieve wafer surface flatness. During the polishing process, the polishing pad and polishing liquid work together to precisely control the pressure, chemical action and mechanical friction of the wafer, so that the surface of the wafer reaches nanometer level flatness.

[0003] The polishing pad is a key component in the polishing process. It can not only store and transfer polishing liquid, but also generate mechanical friction with the wafer, which directly affects the polishing effect of the polished wafer.

[0004] With the continuous advancement of semiconductor process technology, the performance requirements for polishing pads are getting higher and higher. They are required to not only provide good polishing effects, but also have high stability and durability. Therefore, it is urgent to develop a new polishing pad to meet the requirements of advanced semiconductor processes for wafer polishing effects. Summary of the invention

[0005] The present disclosure provides a polishing pad and a polishing device; a new polishing pad can be provided to improve the polishing effect of a wafer.

[0006] The technical solution of the present disclosure is achieved as follows: In a first aspect, the present disclosure provides a polishing pad, comprising: a first polishing part and a second polishing part, wherein the first polishing part and the second polishing part have different polishing degrees for corresponding to-be-polished areas on a wafer.

[0007] In some possible implementations, the first polishing portion and the second polishing portion are made of different materials.

[0008] In some possible implementations, the first polishing part is made of polyurethane, and the second polishing part is made of polyurethane-impregnated polyester felt.

[0009] In some possible implementations, a ratio of an area of ​​the first polishing portion to a total area of ​​the first polishing portion and the second polishing portion is greater than or equal to 20% and less than or equal to 80%.

[0010] In some possible implementations, a ratio of an area of ​​the first polishing portion to a total area of ​​the first polishing portion and the second polishing portion is greater than or equal to 20% and less than or equal to 60%.

[0011] In some possible implementations, the polishing pad includes a plurality of first polishing parts and a plurality of second polishing parts, and the first polishing parts and the second polishing parts are arranged alternately.

[0012] In some possible implementations, the first polishing portion and the second polishing portion are ring-shaped, and the first polishing portion and the second polishing portion are alternately arranged along a radial direction of the polishing pad.

[0013] In some possible implementations, the first polishing parts and the second polishing parts are alternately arranged along the circumferential direction of the polishing pad.

[0014] In some possible implementations, the polishing pad further includes an adhesive portion, and the adhesive portion is used to connect the first polishing portion and the second polishing portion together into a whole.

[0015] In a second aspect, the present disclosure provides a polishing device, comprising the polishing pad according to the first aspect.

[0016] The present disclosure provides a polishing pad and a polishing device; by designing a polishing pad including a first polishing part and a second polishing part, and the first polishing part and the second polishing part have different polishing degrees for corresponding areas to be polished on a wafer, so that different polishing strategies can be adopted for different areas to be polished of the wafer during the polishing process of the wafer, thereby improving the polishing efficiency and polishing effect of the wafer. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the composition of a polishing device in the related art.

[0018] Figure 2 A schematic structural diagram of a polishing pad provided in an embodiment of the present disclosure.

[0019] Figure 3 A box plot of ESFQD of a polished wafer under different area ratios of the first polishing portion provided in an embodiment of the present disclosure.

[0020] Figure 4 A box plot of GBIR of a polished wafer under different area ratios of the first polishing portion provided in an embodiment of the present disclosure.

[0021] Figure 5 A box plot of the nano-morphology of a polished wafer under different area ratios of the first polishing portion provided in an embodiment of the present disclosure.

[0022] Figure 6 A box plot of the surface roughness of a polished wafer under different area ratios of the first polishing portion provided in an embodiment of the present disclosure.

[0023] Figure 7 A schematic diagram of the structure of another polishing pad provided in an embodiment of the present disclosure.

[0024] Figure 8 A schematic structural diagram of another polishing pad provided in an embodiment of the present disclosure.

[0025] Fig. 9 A schematic diagram of a bonding form of the bonding portion provided in an embodiment of the present disclosure.

[0026] Fig.10 A schematic diagram of another bonding form of the bonding portion provided in an embodiment of the present disclosure.

[0027] Fig.11 A schematic diagram of the composition of the polishing equipment provided in an embodiment of the present disclosure. DETAILED DESCRIPTION

[0028] The technical solutions in the present disclosure will be described clearly and completely below in conjunction with the accompanying drawings in the present disclosure.

[0029] It should be noted that, for the sake of clarity, not all features of a specific implementation are described and illustrated in the specification and drawings. Furthermore, in order to avoid unnecessary details that obscure the technical solution focused on by the present disclosure, only the device structure and method steps closely related to the technical solution of the present disclosure are described and illustrated in the specification and drawings, while other details that are not closely related to the technical content of the present disclosure and are known to those skilled in the art are omitted.

[0030] In addition, unless otherwise defined, the technical terms or scientific terms used in the present disclosure should be understood by people with ordinary skills in the field to which the present disclosure belongs. The words "first", "second" and similar words used in the present disclosure do not indicate any order, quantity or importance, but are only used to distinguish different components. Similarly, the words "include" or "comprise" and the like mean that the elements or objects appearing before the word cover the elements or objects listed after the word and their equivalents, without excluding other elements or objects.

[0031] In addition, in the description of the present disclosure, “plurality” means two or more than two, unless otherwise clearly and specifically defined.

[0032] See also Figure 1 , which shows a polishing device 100 in the related art. The polishing device 100 may specifically include: a polishing head 101, an adsorption pad 102, a polishing liquid supply pipeline 103, a polishing disc 104, a polishing pad 105 attached to the polishing disc 104, a first drive shaft 106 and a second drive shaft 107.

[0033] In the process of polishing the wafer W using the polishing device 100, when the adsorption pad 102 is adsorbed on the back of the wafer W, the polishing liquid of a set flow rate is supplied to the polishing pad 105 through the polishing liquid supply pipeline 103. After the polishing liquid is evenly distributed on the polishing pad 105 and contacts the wafer W, the first drive shaft 106 and the second drive shaft 107 are used to drive the polishing plate 104 and the polishing head 101 to rotate relative to each other. In this process, the polishing head 101 applies a certain pressure to the wafer W, thereby completing the polishing operation of the wafer W. Through this polishing operation, the damaged layer of the wafer W generated in the previous process can be removed, and finally the surface of the wafer W can be flattened.

[0034] It can be understood that during the polishing process of the wafer W, the polishing pad 105 can not only store and transfer the polishing liquid, but also provide a certain mechanical friction force to the wafer W to affect the polishing effect of the wafer W. Specifically, the performance of the polishing pad 105, including its material, structure and surface characteristics, has a decisive influence on the polishing effect. In some examples, the surface microstructure of the polishing pad 105 has a specific texture and porosity, which can accommodate and evenly distribute the polishing liquid. In addition, the material and surface characteristics of the polishing pad 105 will also affect the mechanical friction movement between it and the wafer W, thereby affecting the polishing removal rate of the wafer W, and ultimately affecting the polishing effect of the wafer W, such as the nano-morphology, surface roughness, global backside ideal range (GBIR) and edge site flatness front reference least square deviation (ESFQD) of the polished wafer.

[0035] It should be noted that in the present disclosure, the nano-morphology of the above-mentioned polished wafer can be determined by laser interferometry technology. Specifically, for example, for the front side of the polished wafer, by converting the interference light waves irradiated to the front side from the spatial domain to the frequency domain, extracting light waves with wavelengths greater than a set threshold, such as light waves with a wavelength of 20 mm, and converting these light waves with wavelengths greater than the set threshold from the frequency domain to the spatial domain. Then, the surface roughness values ​​at the nanometer level are obtained by Gaussian fitting, and these values ​​are used to simulate the nano-morphology of the front side of the wafer W. It can be understood that the nano-morphology of the front side of the wafer W obtained by the above method will not be affected by long-wave errors such as BOW / WARP.

[0036] Based on this, Figure 2As shown, the present disclosure provides a polishing pad 105, which includes a first polishing portion 1051 and a second polishing portion 1052, and the first polishing portion 1051 and the second polishing portion 1052 have different polishing degrees for the corresponding to-be-polished area on the wafer.

[0037] In some examples, the degree of polishing of the corresponding areas to be polished on the wafer by the first polishing part 1051 and the second polishing part 1052 refers to the levels of surface characteristics such as polishing removal rate, flatness, surface roughness and nanomorphology achieved by the corresponding areas to be polished after the first polishing part 1051 and the second polishing part 1052 polish the corresponding areas to be polished.

[0038] In other examples, the polishing removal rate refers to the amount of excess material removed from the surface of the wafer W per unit time during the polishing process.

[0039] A new polishing pad design is provided in the present disclosure, namely, a polishing pad 105, which is composed of a first polishing portion 1051 and a second polishing portion 1052 having different polishing degrees for different areas to be polished. This design enables different polishing strategies to be adopted for different areas to be polished of the wafer W during the polishing process of the wafer W. For example, the first polishing portion 1051 may be more suitable for quickly removing excess material on the surface of the wafer, while the second polishing portion 1052 may be more capable of achieving fine polishing and improving surface flatness. The polishing pad 105 provided by the present disclosure can improve the overall polishing efficiency and polishing effect of the wafer W.

[0040] In addition, in the present disclosure, by precisely controlling the polishing degrees of different to-be-polished areas by the first polishing part 1051 and the second polishing part 1052 during the polishing process, precise adjustment of the microstructure of the surface of the wafer W can be achieved.

[0041] Of course, by finely controlling the polishing degree of different areas to be polished by the first polishing part 1051 and the second polishing part 1052 in the polishing pad 105, scratches and uneven polishing on the surface of the wafer W can be effectively reduced, so as to improve the surface flatness of the polished wafer W and reduce the surface roughness of the polished wafer W to obtain a better polishing effect.

[0042] for Figure 2 In the technical solution shown, in some possible implementations, the first polishing portion 1051 and the second polishing portion 1052 are made of different materials.

[0043] It can be understood that by designing the polishing pad 105 with the first polishing part 1051 and the second polishing part 1052 of different materials, different polishing parts on the polishing pad 105 can exhibit different chemical and physical properties. This differentiated design can not only improve the material removal selectivity of different to-be-polished areas of the wafer W, but also achieve more precise material removal control during the polishing process, which helps the wafer W to obtain a more uniform and flat surface after polishing.

[0044] In addition, by using different materials of the first polishing part 1051 and the second polishing part 1052 in the polishing pad 105, the mechanical friction effect of the polishing pad 105 on different areas to be polished in the wafer W can be finely controlled. In this case, it helps to reduce scratches and defects on the surface of the polished wafer W, thereby significantly improving the flatness of the surface of the wafer W and reducing the surface roughness.

[0045] It is understandable that the polishing pad 105 provided by the present disclosure can also adjust the material according to different polishing stages to adapt to different polishing requirements. For example, in the rough polishing stage, a higher polishing removal rate may be required to quickly remove the damaged layer on the surface of the wafer W. In the fine polishing stage, more attention is paid to the nano-morphological characteristics and flatness of the surface of the wafer W. Therefore, by accurately controlling the material at different parts of the polishing pad 105, the polishing amount of different areas to be polished on the corresponding wafer W can be reasonably controlled, thereby achieving precise adjustment of the surface microstructure of the wafer W.

[0046] for Figure 2 In the technical solution shown, in some possible implementations, the first polishing part 1051 is made of polyurethane (PU) material, and the second polishing part 1052 is made of polyurethane impregnated polyester felt (PUI). It should be noted that in the present disclosure, PUIImpregnated Polyester Felts is referred to as SUBA material.

[0047] It can be understood that in the present disclosure, the polishing pad 105 is designed to include a first polishing part 1051 and a second polishing part 1052, and the first polishing part 1051 is made of PU material, and the second polishing part 1052 is made of SUBA material, aiming to improve the polishing effect of wafer W through the combination of these two materials. This is mainly because the first polishing part 1051 made of PU material has high wear resistance, which can effectively resist wear during the polishing process of wafer W, and help to improve the polishing removal rate, especially in the rough polishing stage, and can quickly remove the damaged layer on the surface of wafer W. In addition, the first polishing part 1051 made of PU material has a porous structure, which can absorb and buffer the pressure of the polishing liquid and abrasive particles during the polishing process, effectively prevent over-polishing of wafer W, and thus improve the GBIR of wafer W. On the other hand, the first polishing part 1051 made of PU material can eliminate or improve the impact of the previous processing steps on the surface of wafer W to a greater extent.

[0048] The second polishing portion 1052 made of SUBA material has high porosity and good water permeability, so that the polishing liquid can penetrate into the interior of the polishing pad 105 to give full play to the chemical action of the polishing liquid. In addition, the second polishing portion 1052 made of SUBA material enhances the elasticity of the polishing pad 105, helps to reduce the ESFQD of the wafer W, and improves the nano-morphology and surface roughness of the wafer W.

[0049] For the above-mentioned embodiment, in some examples, the ratio of the area of ​​the first polishing portion 1051 to the total area of ​​the first polishing portion 1051 and the second polishing portion 1052 is greater than or equal to 20% and less than or equal to 80%.

[0050] In the present disclosure, the polishing pad 105 is designed so that the ratio of the area of ​​the first polishing portion 1051 to the total area of ​​the first polishing portion 1051 and the second polishing portion 1052 is between 20% and 80%, so as to further optimize the GBIR of the polished wafer W by adjusting the ratio of the area of ​​the first polishing portion 1051. Of course, since the total area of ​​the first polishing portion 1051 and the second polishing portion 1052 is fixed, adjusting the ratio of the area of ​​the first polishing portion 1051 is equivalent to adjusting the ratio of the area of ​​the second polishing portion 1052, which is very important for reducing the ESFQD of the wafer, and the nano-morphology and surface roughness of the polished wafer W can also be improved by adjusting the ratio of the area of ​​the first polishing portion 1051.

[0051] In other words, by adjusting the area ratio of the first polishing part 1051 and the second polishing part 1052, the hardness, elasticity, wear resistance and polishing removal rate of the polishing pad 105 can be regulated, thereby improving the polishing efficiency and the surface quality of the polished wafer W. For example, increasing the area ratio of the first polishing part 1051 can improve the polishing removal rate, while increasing the area ratio of the second polishing part 1052 is helpful to improve the surface quality of the polished wafer.

[0052] Of course, limiting the area ratio of the first polishing portion 1051 and the second polishing portion 1052 helps to extend the service life of the polishing pad 105. This is mainly due to the combination of the wear resistance of the PU material and the high porosity of the SUBA material, which can reduce the wear of the polishing pad 105 while maintaining efficient polishing, thereby extending the service life of the polishing pad 105 and reducing the replacement frequency.

[0053] Optionally, a ratio of an area of ​​the first polishing portion 1051 to a total area of ​​the first polishing portion 1051 and the second polishing portion 1052 is greater than or equal to 20% and less than or equal to 60%.

[0054] Specifically Figure 2 For example, the structure of the polishing pad 105 shown in FIG. Figures 3 to 6 As shown, it shows the box plots of ESFQD, GBIR, nano-morphology and surface roughness of the polished wafer W under different area ratios of the first polishing part 1051. Figure 3 It can be seen that as the area ratio of the first polishing portion 1051 in the polishing pad 105 decreases or the area ratio of the second polishing portion 1052 increases, the ESFQD of the polished wafer W decreases. This is mainly because the ESFQD of the polished wafer W is greatly affected by the material of the polishing pad 105. Figure 4 It can be seen that as the area ratio of the first polishing portion 1051 in the polishing pad 105 decreases or the area ratio of the second polishing portion 1052 increases, the GIBR of the polished wafer W tends to decrease first and then increase. Figure 5 It can be seen that as the area ratio of the first polishing portion 1051 in the polishing pad 105 decreases or the area ratio of the second polishing portion 1052 increases, the nano-morphology of the polished wafer W first decreases and then increases. Figure 4 and Figure 5 It can be seen that by adjusting the area ratio of the first polishing part 1051 and the area ratio of the second polishing part 1052, the GIBR and nano-morphology of the polished wafer W can be better than the GIBR and nano-morphology of the wafer W polished by a polishing pad of a single material. Figure 6It can be seen that as the area ratio of the first polishing part 1051 in the polishing pad 105 decreases or the area ratio of the second polishing part 1052 increases, the surface roughness of the polished wafer W shows an overall decreasing trend, indicating that the decrease in the area ratio of the first polishing part 1051 in the polishing pad 105 or the area ratio of the second polishing part 1052 has an important influence on the surface roughness of the polished wafer W. Figure 6 It can be seen that by adjusting the area ratio of the first polishing part 1051 and the area ratio of the second polishing part 1052 , the surface roughness of the polished wafer W can be made substantially equal to the surface roughness of the wafer W polished by a polishing pad made of a single SUBA material.

[0055] That is to say, combining Figures 3 to 6 It can be concluded that by adjusting the area ratio of the first polishing part 1051 and the second polishing part 1052 , the polishing effect of the polished wafer W can be significantly affected. Therefore, in the specific implementation process, the area ratio of the first polishing part 1051 and the second polishing part 1052 can be adjusted according to the polishing requirements of the polished wafer W.

[0056] for Figure 2 In some possible implementations of the technical solution shown, Figure 7 As shown, the polishing pad 105 includes a plurality of first polishing parts 1051 and a plurality of second polishing parts 1052 , and the first polishing parts 1051 and the second polishing parts 1052 are arranged alternately.

[0057] In the present disclosure, by alternately arranging a plurality of first polishing parts 1051 and a plurality of second polishing parts 1052, a more uniform polishing removal rate can be achieved during the polishing process. This is because the first polishing parts 1051 and the second polishing parts 1052 have different polishing characteristics, and such an arrangement design helps to achieve a more consistent polishing effect on the surface of the entire wafer W. In addition, the alternating arrangement of the first polishing parts 1051 and the second polishing parts 1052 can better control the local polishing effect of the wafer W during the polishing process, especially in the edge area and the center area of ​​the wafer W, which is crucial to improving the ESFQD and nanomorphology of the wafer W.

[0058] For the above-mentioned embodiments, in some examples, the first polishing part 1051 and the second polishing part 1052 are ring-shaped, and the first polishing part 1051 and the second polishing part 1052 are alternately arranged along the radial direction of the polishing pad 105 .

[0059] Specifically, Figure 7As shown, in the specific implementation process, the first polishing part 1051 and the second polishing part 1052 are ring-shaped and alternately arranged along the radial direction of the polishing pad 105. This design can achieve a more uniform polishing removal rate on the surface of the entire wafer W during the polishing process, so as to greatly improve the GBIR of the wafer W.

[0060] In addition, the alternatingly arranged annular first polishing part 1051 and second polishing part 1052 can better implement different polishing strategies for different areas to be polished on the wafer W during the polishing process. For example, a higher polishing removal rate may be required in the center area of ​​the wafer W to quickly remove materials, while a more refined polishing operation may be required in the edge area or other specific areas to reduce surface roughness and improve local flatness. Through this design, the polishing pad 105 can flexibly adapt to the polishing requirements of the wafer W to achieve efficient and high-quality polishing effects.

[0061] Optionally, in some examples, the first polishing portion 1051 and the second polishing portion 1052 have the same width along the radial direction of the polishing pad 105 .

[0062] In this case, it can be ensured that during the polishing process, each area on the wafer W along the radial direction of the polishing pad 105 can obtain a consistent polishing removal rate, which helps to achieve uniform flatness of the surface of the polished wafer W. In addition, since the widths of the first polishing part 1051 and the second polishing part 1052 are consistent, uniform polishing pressure distribution can be achieved on the entire surface of the wafer W, reducing the uneven surface of the polished wafer W caused by local pressure differences, so as to improve the surface quality and polishing efficiency of the polished wafer W.

[0063] For the above implementations, in some examples, such as Figure 8 As shown, the first polishing parts 1051 and the second polishing parts 1052 are alternately arranged along the circumferential direction of the polishing pad 105 .

[0064] This is because the alternating arrangement of the first polishing part 1051 and the second polishing part 1052 along the circumferential direction of the polishing pad 105 can ensure that during the polishing process, the polishing removal rates of various areas in the circumferential direction of the wafer W remain consistent, which helps to obtain good flatness uniformity on the surface of the polished wafer W.

[0065] It should be noted that in the present disclosure, the shapes of the first polishing part 1051 and the second polishing part 1052 and their alternating arrangement are not limited to the form described in the above technical solution. For example, the shapes of the first polishing part 1051 and the second polishing part 1052 can be square or hexagonal, and the polishing pad 105 is obtained by splicing them in an alternating arrangement.

[0066] In addition, in the present disclosure, the shape of the polishing pad 105 is not limited to a circle, and its shape can be determined according to specific polishing requirements.

[0067] for Figure 2 In some possible implementations of the technical solution shown, Fig. 9 As shown, the polishing pad 105 further includes an adhesive portion 1053 , and the adhesive portion 1053 is used to connect the first polishing portion 1051 and the second polishing portion 1052 together into a whole.

[0068] In the present disclosure, the first polishing part 1051 and the second polishing part 1052 are connected together into a whole through the bonding part 1053, thereby enhancing the overall structural stability of the polishing pad 105 to ensure that the first polishing part 1051 and the second polishing part 1052 of different materials in the polishing pad 105 will not be relatively displaced or separated during the polishing process, thereby maintaining the continuity and consistency of the polishing operation, and further ensuring the uniformity and reliability of the polishing effect.

[0069] In addition, the first polishing part 1051 and the second polishing part 1052 are connected together into a whole through the bonding part 1053, which can improve the durability of the polishing pad 105 and extend its service life.

[0070] It should be noted that the bonding form of the bonding portion 1053 is not limited to Fig.10 The bonding form of the bonding part 1053 can also be as shown in the following example: Fig.10 As shown, the first polishing portion 1051 and the second polishing portion 1052 are connected together into a whole through the side portions of the first polishing portion 1051 and the second polishing portion 1052 .

[0071] Finally, see Fig.11 The present disclosure also provides a polishing device 100, which includes a polishing pad 105 according to the aforementioned technical solution.

[0072] It should be noted that the technical solutions described in the present disclosure can be combined arbitrarily without conflict.

[0073] The above is only a specific embodiment of the present disclosure, but the protection scope of the present disclosure is not limited thereto. Any person skilled in the art who is familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present disclosure, which should be included in the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure should be based on the protection scope of the claims.

Claims

1. A polishing pad, characterized in that: The polishing pad comprises a first polishing part and a second polishing part, and the first polishing part and the second polishing part have different polishing degrees for the corresponding to-be-polished area on the wafer.

2. The polishing pad according to claim 1, characterized in that The first polishing part and the second polishing part correspond to different materials.

3. The polishing pad according to claim 2, characterized in that The first polishing part is made of polyurethane, and the second polishing part is made of polyurethane impregnated polyester felt.

4. The polishing pad according to claim 3, characterized in that A ratio of an area of ​​the first polishing portion to a total area of ​​the first polishing portion and the second polishing portion is greater than or equal to 20% and less than or equal to 80%.

5. The polishing pad according to claim 4, characterized in that A ratio of an area of ​​the first polishing portion to a total area of ​​the first polishing portion and the second polishing portion is greater than or equal to 20% and less than or equal to 60%.

6. The polishing pad according to any one of claims 1 to 5, characterized in that The polishing pad includes a plurality of first polishing parts and a plurality of second polishing parts, and the first polishing parts and the second polishing parts are arranged alternately.

7. The polishing pad according to claim 6, characterized in that The first polishing portion and the second polishing portion are ring-shaped, and the first polishing portion and the second polishing portion are alternately arranged along a radial direction of the polishing pad.

8. The polishing pad according to claim 6, characterized in that The first polishing parts and the second polishing parts are alternately arranged along a circumferential direction of the polishing pad.

9. The polishing pad according to claim 1, characterized in that The polishing pad further includes an adhesive portion, and the adhesive portion is used to connect the first polishing portion and the second polishing portion together into a whole.

10. A polishing device, characterized in that: The polishing apparatus comprises the polishing pad according to any one of claims 1 to 9.

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