Polishing star wheel

Abstract

A polishing star wheel includes a wheel body, at least one workpiece hole penetrating through the wheel body, and an inner liner arranged on a sidewall of the workpiece hole. The inner liner includes an inner side surface and an outer side surface arranged radially along the workpiece hole. The inner side surface is used to contact a workpiece arranged in the workpiece hole, and the outer side surface is used to contact the sidewall of the workpiece hole. In the axial direction of the workpiece hole, the upper end of the inner side surface protrudes from the upper surface of the wheel body, and the lower end of the inner side surface protrudes from or is flush with the lower surface of the wheel body. The height of the inner side surface is less than the initial thickness of the workpiece and greater than the final thickness of the workpiece. The polishing star wheel can improve the edge over-polishing or edge rolling phenomenon of the polished workpiece.

Description

Technical Field

[0001] This invention relates to the field of integrated circuit manufacturing technology, and in particular to a planetary wheel for polishing. Background Technology

[0002] Semiconductor polishing is a surface treatment technique for semiconductor materials, designed to improve their surface smoothness and gloss, thus laying the foundation for subsequent semiconductor device manufacturing. Semiconductor polishing has significant applications in integrated circuits, optoelectronic devices, and microelectronics manufacturing. As the integration density of integrated circuits increases, the requirements for the smoothness and gloss of semiconductor surfaces also become more stringent, placing higher demands on semiconductor polishing processes.

[0003] Chemical mechanical polishing (DSP) is a key surface treatment technology in semiconductor polishing processes, used to process silicon wafers to obtain substrate materials with high flatness and smoothness. During DSP, the silicon wafer is placed in a planetary wheel, and the wafer and the planetary wheel rotate together following the internal and external gears of the polishing apparatus, moving relative to the upper and lower polishing pads, thus completing the polishing of the silicon wafer under the action of the polishing slurry.

[0004] However, in chemical mechanical polishing (CMP), the silicon wafer rotates and revolves within a planetary gear, which also rotates and revolves between internal and external gears. This unpredictable motion between the silicon wafer and the polishing pad makes precise control of pressure and other process parameters, unlike in CMP, impossible. Consequently, the stress on the wafer's edge and center differs. The edge region experiences greater stress, leading to excessively high edge removal rates, resulting in over-polishing or edge roll-off. Reduced edge flatness negatively impacts subsequent edge lithography and etching processes, ultimately reducing wafer yield and the utilization rate of large silicon wafers.

[0005] In the chemical mechanical polishing process, there are generally four control methods to address over-polishing or edge roll-off of silicon wafers:

[0006] The first control method is to optimize the design of the polishing pad. By improving the design of the polishing pad, such as adjusting its hardness, the deformation of the polishing pad at the edge of the silicon wafer can be reduced, thereby reducing stress concentration at the wafer edge and thus reducing wafer edge roll-off. The advantage is that optimizing the polishing pad design does not require additional equipment investment and has wide applicability. However, the main disadvantages are that it requires multiple trials and adjustments to find the optimal polishing pad design; an overly hard polishing pad design will further reduce the surface quality of the silicon wafer; and in some cases, optimizing the polishing pad design may increase production costs.

[0007] The second control method is to adjust the polishing parameters. By adjusting polishing parameters, such as rotation speed and pressure, the force exerted by the polishing pad on the edge of the silicon wafer can be controlled, thereby reducing the occurrence of roll-off. However, this also requires detailed parameter optimization and experimentation of the polishing process, which is time-consuming and resource-intensive; it may also affect other processing parameters, potentially requiring recalibration of the entire processing flow.

[0008] The third control method is to optimize the edge support structure. By optimizing the support structure at the edge of the silicon wafer, such as changing the design of the planetary gear or adding edge fixing devices, edge stability can be improved and the rolling-off phenomenon reduced. However, this also requires modifications or improvements to the equipment structure, which may require replacing existing equipment components; modifications to the equipment may require additional costs and may affect the stability and reliability of the equipment.

[0009] The fourth control method is to introduce edge control technology. Introducing specialized edge control technologies, such as edge adsorption devices or edge magnetic fixing devices, can stabilize the edge position of the silicon wafer during processing, reducing the occurrence of rolling-off. This requires additional equipment investment and technical support, increasing production costs; introducing new edge control technologies may also require redesigning and adjusting the processing flow, affecting production efficiency and stability.

[0010] Given the shortcomings of the aforementioned control methods, providing a simpler and more effective control method to improve the over-polishing or edge roll-off phenomenon of silicon wafers has become one of the current research focuses. Summary of the Invention

[0011] The technical problem to be solved by the present invention is to provide a simpler and more effective control method to improve the phenomenon of over-polishing or edge rolling of the polished workpiece.

[0012] To address the aforementioned problems, the present invention provides a planetary wheel for polishing, comprising: a wheel body; at least one workpiece hole penetrating the wheel body; and a liner disposed on the sidewall of the workpiece hole. The liner includes an inner side and an outer side disposed radially along the workpiece hole. The inner side is used to contact a workpiece disposed in the workpiece hole, and the outer side contacts the sidewall of the workpiece hole. In the axial direction of the workpiece hole, the upper end of the inner side protrudes beyond the upper surface of the wheel body, and the lower end of the inner side protrudes beyond the lower surface of the wheel body or is flush with the lower surface of the wheel body. The height of the inner side is less than the initial thickness of the workpiece and greater than the final thickness of the workpiece.

[0013] In one embodiment, the height difference between the upper end of the inner side surface and the upper end of the outer side surface is greater than the height difference between the lower end of the inner side surface and the lower end of the outer side surface.

[0014] In one embodiment, the height difference between the upper end of the inner side surface and the upper end of the outer side surface is 6 to 8 micrometers.

[0015] In one embodiment, when the lower end of the inner side protrudes beyond the lower surface of the wheel body, the height difference between the lower end of the inner side and the lower end of the outer side is 0.5 to 1 micrometer.

[0016] The upper end of the outer side is flush with the upper surface of the wheel body, and the lower end of the outer side is flush with the lower surface of the wheel body.

[0017] In one embodiment, the longitudinal section of the liner is wedge-shaped.

[0018] In one embodiment, the upper and lower ends of the inner surface have chamfers.

[0019] In one embodiment, the sidewall of the workpiece hole has an internal gear, and the outer side of the liner has an external gear. The internal gear meshes with the external gear to fix the liner inside the workpiece hole.

[0020] In one embodiment, the liner is secured to the disc body by a pin assembly.

[0021] The polishing planetary wheel provided in this embodiment of the invention has a liner inside the workpiece hole. Axially, the upper end of the inner side of the liner protrudes beyond the upper surface of the wheel body. The height of the inner side is less than the initial thickness of the workpiece but greater than its final thickness. During the polishing process, when the workpiece is thinned to a certain thickness, the upper end of the inner side of the liner can contact and support the upper polishing pad, causing the upper polishing pad to disengage from the edge of the workpiece. Therefore, during the period when the workpiece continues to be thinned to its final thickness, the upper polishing pad does not contact the edge of the workpiece, preventing further grinding of the workpiece edge. This effectively reduces stress concentration at the workpiece edge, improves over-polishing or edge rolling phenomena, enhances the uniformity and consistency of polishing, and ultimately improves the polishing quality and stability of the workpiece. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a top view of a polishing planetary wheel provided in an embodiment of the present invention;

[0024] Figure 2 yes Figure 1 Cross-sectional view of line AA;

[0025] Figure 3 This is a cross-sectional view of a polishing planetary wheel in use according to an embodiment of the present invention;

[0026] Figure 4 This is a cross-sectional view of the inner side of the liner of a planetary wheel for polishing provided in another embodiment of the present invention;

[0027] Figure 5 This is a cross-sectional view of the polishing planetary wheel in use according to another embodiment of the present invention;

[0028] Figure 6 The figures are von Mises stress curves of the upper surface of the silicon wafer during the polishing process using the comparative example planetary wheel and the planetary wheel provided by the present invention. Figure (a) shows the von Mises stress curve of the upper surface of the silicon wafer during the polishing process using the comparative example planetary wheel, and Figure (b) shows the von Mises stress curve of the upper surface of the silicon wafer during the polishing process using the planetary wheel provided by the present invention.

[0029] Figure 7 yes Figure 6 A comparison chart of the numerical values ​​of the peak values ​​of the von Mises stress curves;

[0030] Figure 8 The figures show the edge contact stress curves of silicon wafers during the polishing process using a comparative example planetary wheel and the planetary wheel provided by the present invention. Figure (a) shows the edge contact stress curve of silicon wafers during the polishing process using a comparative example planetary wheel, and Figure (b) shows the edge contact stress curve of silicon wafers during the polishing process using the planetary wheel provided by the present invention.

[0031] Figure 9 yes Figure 8 A comparison chart of the numerical values ​​of the peak contact stress. Detailed Implementation

[0032] The specific embodiments of the polishing planetary wheel provided by the present invention will be described in detail below with reference to the accompanying drawings.

[0033] Figure 1 This is a top view of a polishing planetary wheel provided in an embodiment of the present invention. Figure 2 yes Figure 1 Cross-sectional view of line AA in the middle. Figure 3 This is a cross-sectional view of a polishing planetary wheel in use according to an embodiment of the present invention. Please refer to [link / reference]. Figures 1-3The polishing planetary wheel includes: a wheel body 100; at least one workpiece hole 110 penetrating the wheel body 100; and a liner 120 disposed on the sidewall of the workpiece hole 110. The liner 120 includes an inner side surface 121 and an outer side surface 122 disposed radially D along the workpiece hole 110. The inner side surface 121 is used to contact a workpiece 130 disposed in the workpiece hole 110, and the outer side surface 122 contacts the sidewall of the workpiece hole 110. In the axial direction O of the workpiece hole 110, the upper end 121a of the inner side surface 121 protrudes from the upper surface 100a of the wheel body 100, and the lower end 121b of the inner side surface 121 protrudes from the lower surface 100b of the wheel body 100 or is flush with the lower surface 100b of the wheel body 100. The height H1 of the inner side surface 121 is less than the initial thickness of the workpiece 130 and greater than the final thickness of the workpiece 130.

[0034] Along the axial direction O of the workpiece hole 110, the upper surface 100a of the wheel body 100 is used to contact the upper polishing pad 200 of the polishing equipment, and the lower surface 100b of the wheel body 100 is used to contact the lower polishing pad 210 of the polishing equipment. During the polishing operation, the planetary wheel and the workpiece 130 are placed on the surface of the lower polishing pad 210, and the upper polishing pad 200 is disposed on the upper surface of the planetary wheel and the workpiece 130. Because the edge area of ​​the workpiece 130 is subjected to greater force than the center area, the cleaning rate of the edge area is too high, resulting in over-polishing or edge rolling of the workpiece 130.

[0035] The polishing planetary wheel provided in this embodiment of the invention has a liner 120 inside the workpiece hole 110. On the axial direction O of the workpiece hole 110, the upper end 121a of the inner side surface 121 of the liner 120 protrudes from the upper surface 100a of the wheel body 100. The height H1 of the inner side surface 121 is less than the initial thickness of the workpiece 130 and greater than the final thickness of the workpiece 130. During the polishing process, when the workpiece 130 is thinned to a certain thickness, the upper end 121a of the inner side surface 121 of the liner 120 can contact and support the upper polishing pad 200, causing the upper polishing pad 200 to detach from the edge of the workpiece 130. During the period when the workpiece 130 continues to be thinned to the final thickness, the upper polishing pad 200 does not contact the edge of the workpiece 130 and cannot continue to grind the edge of the workpiece 130. This effectively reduces the stress concentration at the edge of the workpiece 130, improves the over-polishing or edge rolling phenomenon of the workpiece 130 edge, improves the uniformity and consistency of polishing, and thus improves the polishing quality and stability of the workpiece 130.

[0036] A planetary wheel is a fixture used in various planar polishing processes for glass, lenses, silicon wafers, hard disks, etc. Its function is to maintain and guide the movement of the workpiece during polishing. During the polishing process, the workpiece 130 is placed within the workpiece hole 110, which limits the workpiece 130. The workpiece 130 revolves and rotates with the planetary wheel, thus moving relative to the upper polishing pad 200 and the lower polishing pad 210, achieving polishing of the workpiece 130. The initial thickness of the workpiece 130 is greater than the thickness of the wheel body 100, and the upper surface of the workpiece 130 protrudes beyond the upper surface 100a of the wheel body 100. As polishing progresses, the upper surface of the workpiece 130 may be flush with or slightly lower than the upper surface 100a of the wheel body 100.

[0037] The material of the wheel body 100 is usually metal. However, direct contact between metal and the workpiece 130 can cause damage to the edge of the workpiece 130. Therefore, an inner liner 120 needs to be added between the wheel body 100 and the silicon wafer to prevent contact between them. The material of the inner liner 120 is mainly rigid plastic, including but not limited to polyvinylidene fluoride (PVDF).

[0038] The inner surface 121 of the liner 120 is used to contact the workpiece 130. In some embodiments, the diameter of the inner surface 121 of the liner 120 is smaller than the diameter of the workpiece 130, so that the workpiece 130 can rotate within the workpiece hole 110.

[0039] Along the axial direction O of the workpiece hole 110, the upper end 121a of the inner side surface 121 is the highest point of the inner liner 120, protruding from the upper surface 100a of the wheel body 100, and lower than the surface of the workpiece 130 at its initial thickness, but higher than the surface of the workpiece 130 at its final thickness. In the initial stage of the polishing process, the upper polishing pad 200 can directly contact the edge of the workpiece 130 to polish the edge area of ​​the workpiece 130; in the later stage of the polishing process, the inner liner 120 contacts and supports the upper polishing pad 200, and the upper polishing pad 200 does not contact the edge of the workpiece 130, thus preventing further grinding of the edge of the workpiece 130. This effectively reduces stress concentration at the edge of the workpiece 130 and improves the over-polishing or edge rolling phenomenon of the workpiece 130 edge.

[0040] Along the axial direction O of the workpiece hole 110, the lower end 121b of the inner side surface 121 protrudes from the lower surface 100b of the wheel body 100. During the polishing process, polishing fluid is present between the lower surface of the workpiece 130 and the lower polishing pad 210. The workpiece 130 is subjected to the buoyancy of the polishing fluid, resulting in a slight distance between the workpiece 130 and the lower polishing pad 210. The lower end 121b of the inner side surface 121 contacts the lower polishing pad 210 of the polishing equipment. The lower end 121b of the inner side surface 121 can support the lower polishing pad 210 of the polishing equipment, making the distance between the lower polishing pad 210 and the edge area of ​​the workpiece 130 greater than the distance between the workpiece 130 and the lower polishing pad 210 due to buoyancy. This reduces the force exerted by the lower polishing pad 210 on the workpiece 130, effectively reducing stress concentration at the edge of the workpiece 130 and improving the over-polishing or edge rolling phenomenon of the workpiece 130.

[0041] The outer surface 122 of the liner 120 contacts the sidewall of the workpiece hole 110, serving to fix the liner 120 relative to the wheel body 100. For example, in one embodiment, the sidewall of the workpiece hole 110 has an internal gear, and the outer surface 122 of the liner 120 has an external gear. The internal gear meshes with the external gear to fix the liner 120 within the workpiece hole 110. During polishing, due to the limiting effect of the internal gear on the external gear, the liner 120 can rotate with the wheel body 100 without rotating relative to the wheel body 100, or only undergoing slight movement relative to the wheel body 100, further increasing the supporting effect of the liner 120 on the upper polishing pad 200. In another embodiment, the liner 120 is fixed to the wheel body 100 by a pin assembly. The pin assembly may include a pin disposed on the outer surface 122 of the inner liner 120 and an insertion hole disposed on the side wall of the workpiece hole 110. The pin is inserted into the insertion hole to fix the inner liner 120. It is understood that the pin of the pin assembly may be disposed on the side wall of the workpiece hole 110, and the insertion hole may be disposed on the outer surface 122 of the inner liner 120.

[0042] In one embodiment, the upper end 122a of the outer side surface 122 of the inner liner 120 is flush with the upper surface 100a of the wheel body 100, and the lower end 122b of the outer side surface 122 is flush with the lower surface 100b of the wheel body 100. That is, the height of the outer side surface 122 of the inner liner 120 is the same as the thickness of the wheel body 100. The outer side surface 122 of the inner liner 120 can better fit the side wall of the workpiece hole 110, avoiding gaps between the outer side surface 122 of the inner liner 120 and the side wall of the workpiece hole 110, and avoiding affecting the flow field distribution of the polishing fluid during the polishing process, thereby affecting the polishing effect.

[0043] To further and effectively improve the problem of over-polishing or edge rolling of workpiece 130, the inventors conducted in-depth research. The inventors discovered that during the polishing process, the stress on the upper surface of workpiece 130 is higher than the stress on the lower surface. Further research into the polishing process of workpiece 130 revealed that during polishing, external pressure is applied to workpiece 130 from the upper polishing pad 200, while the lower polishing pad 210 does not directly apply pressure. This results in greater stress on the upper surface of workpiece 130, leading to a higher stress on the upper surface compared to the lower surface.

[0044] In view of this, the planetary wheel for polishing provided in this embodiment of the invention has the inner liner 120 configured such that the height difference H2 between the upper end 121a of the inner side surface 121 and the upper end 122a of the outer side surface 122 is greater than the height difference H2 between the lower end 121b of the inner side surface 121 and the lower end 122b of the outer side surface 122. The stress on the upper surface of the workpiece 130 is further reduced by increasing the height difference H2 between the upper end 121a of the inner side 121 and the upper end 122a of the outer side 122; the stress on the lower surface of the workpiece 130 is reduced by setting the height difference H3 between the lower end 121b of the inner side 121 and the lower end 122b of the outer side 122; and the stress difference between the upper and lower surfaces of the edge region of the workpiece 130 is balanced by setting the height difference H2 between the upper end 121a of the inner side 121 and the upper end 122a of the outer side 122 to be greater than the height difference H3 between the lower end 121b of the inner side 121 and the lower end 122b of the outer side 122, thereby effectively reducing the stress concentration at the edge of the workpiece 130 and improving the over-polishing or rolling-off phenomenon at the edge of the workpiece 130. In some embodiments, the height difference H2 between the upper end 121a of the inner side 121 and the upper end 122a of the outer side 122 is 6 to 8 micrometers, and the height difference H3 between the lower end 121b of the inner side 121 and the lower end 122b of the outer side 122 is 0.5 to 1 micrometer.

[0045] In some embodiments, the longitudinal section of the liner 120 is wedge-shaped, and the upper end 121a of the inner side surface 121 and the upper end 122a of the outer side surface 122 can be connected by a flat inclined surface, such as... Figure 2 As shown, the upper end 121a of the inner side 121 and the upper end 122a of the outer side 122 can be connected by a stepped or curved inclined surface; the lower end 121b of the inner side 121 and the lower end 122b of the outer side 122 can be connected by a flat inclined surface, such as... Figure 2 As shown, the lower end 121b of the inner side 121 and the lower end 122b of the outer side 122 are connected by a stepped or curved slope.

[0046] In another embodiment, such as Figure 4 As shown, it is a cross-sectional view of the inner side 121 of the inner liner 120 of the planetary wheel for polishing provided in another embodiment of the present invention. The upper end 121a and the lower end 121b of the inner side 121 have chamfers. The chamfers are arc-shaped, thereby preventing the upper end 121a and the lower end 121b of the inner side 121 of the inner liner 120 from being too sharp and scratching the surface of the workpiece 130.

[0047] In the above embodiment, the lower end 121b of the inner side surface 121 of the liner 120 protrudes beyond the lower surface 100b of the wheel body 100, while in another embodiment, such as Figure 5 As shown, this is a cross-sectional view of a polishing planetary wheel in use according to another embodiment of the present invention. The lower end 121b of the inner side surface 121 of the liner 120 is flush with the lower surface 100b of the wheel body 100. When the upper end 121a of the inner side surface 121 of the liner 120 contacts the upper polishing pad 200, the liner 120 is simultaneously squeezed by the upper polishing pad 200 and the lower polishing pad 210. If the lower end 121b of the inner side surface 121 of the liner 120 deforms under this squeezing, the height of the liner 120 decreases, and the upper polishing pad 200 comes into contact with the surface of the edge area of ​​the workpiece 130, resulting in over-polishing of the edge area of ​​the workpiece 130. In this embodiment, by designing the lower end 121b of the inner side surface 121 of the liner 120 to be flush with the lower surface 100b of the wheel body 100, the contact area between the lower end 121b of the inner side surface 121 of the liner 120 and the lower polishing pad 210 of the polishing equipment is increased, effectively avoiding deformation of the lower end 121b of the inner side surface 121 of the liner 120, and further preventing the edge area of ​​the workpiece 130 from being over-polished.

[0048] The polishing planetary wheel provided in this embodiment of the invention has an inner liner 120 inside the workpiece hole 110. The height design of the inner liner 120 effectively reduces stress concentration at the edge of the workpiece 130, improving over-polishing or edge rolling phenomena, enhancing the uniformity and consistency of polishing, and thus improving the polishing quality and stability of the workpiece 130. In some embodiments, the height of the inner liner 120, the height difference between the upper end 121a of the inner side 121 and the upper end 122a of the outer side 122 of the inner liner 120, and the height difference between the lower end 121b of the inner side 121 and the lower end 122b of the outer side 122 of the inner liner 120 can be adjusted according to the initial and final thickness of the workpiece 130. This allows the stress condition of the edge area of ​​the workpiece 130 to be controlled quickly, further improving the flatness of the silicon wafer edge. Furthermore, the polishing planetary wheel provided in this embodiment of the invention has wide applicability, suitable for various workpiece 130 sizes and polishing requirements, and possesses high versatility and practicality.

[0049] The planetary wheel for polishing provided in this embodiment of the invention can improve the over-polishing or edge rolling phenomenon of the workpiece 130 simply by changing the shape of the inner liner 120. No precise adjustment is required, the adjustment scheme is easy to implement, it does not have an additional impact on the overall polishing rate of the workpiece 130, and the process is simple to operate, does not generate additional expenses in the polishing process, and has strong applicability.

[0050] The inventors further conducted simulation verification of the technical effect of the polishing planetary wheel provided in the embodiments of the present invention.

[0051] Figure 6 Figure 1 shows the von Mises stress curves of the upper surface of the silicon wafer during the polishing process using the comparative example planetary wheel and the planetary wheel provided by the present invention. Figure 2 shows the von Mises stress curve of the upper surface of the silicon wafer during the polishing process using the comparative example planetary wheel and Figure 3 shows the von Mises stress curve of the upper surface of the silicon wafer during the polishing process using the planetary wheel provided by the present invention. Jut-out is the difference between the height of the silicon wafer and the height of the inner side surface of the liner. Figure 7 yes Figure 6 A comparison of the numerical values ​​of the peak values ​​of the von Mises stress curves. Figure 8 The figures show the edge contact stress curves of silicon wafers during the polishing process using a comparative example planetary wheel and the planetary wheel provided by the present invention. Figure (a) shows the edge contact stress curve of silicon wafers during the polishing process using a comparative example planetary wheel, and Figure (b) shows the edge contact stress curve of silicon wafers during the polishing process using the planetary wheel provided by the present invention. Jut-out is the difference between the height of the silicon wafer and the height of the inner side of the liner. Figure 9 yes Figure 8 A comparison chart of the numerical values ​​of the peak contact stress.

[0052] The comparative example planetary wheel's inner liner design is as follows: the upper ends of both the inner and outer sides are flush with the upper surface of the wheel body, and the lower ends of both the inner and outer sides are flush with the lower surface of the wheel body. In other words, the thickness of the inner liner is the same as the thickness of the wheel body, and the inner liner does not protrude from the wheel body. In this simulation verification, the thickness of the inner liner of the comparative example planetary wheel is 781 micrometers, and the height of the inner side of the inner liner of the planetary wheel in this application is 785 micrometers.

[0053] from Figure 6 As shown in Figure (a), the von Mises stress curve on the silicon wafer surface has two peaks. When the planetary wheel of the comparative example is applied during polishing, the stress curve only begins to change when the height difference between the liner and the silicon wafer is less than 2 micrometers. As polishing progresses and the silicon wafer becomes thinner, the von Mises stress curve tends to become more uniform. However, when the planetary wheel provided in this embodiment of the invention is applied during polishing, from... Figure 6 As shown in Figure (b), the von Mises stress curve of the silicon wafer begins to decrease when the height difference between the liner and the silicon wafer is less than 6 micrometers, and gradually becomes more uniform as polishing progresses. The planetary wheel liner design provided in this embodiment of the invention allows the edge of the silicon wafer to separate from the upper polishing pad earlier, suppressing the edge removal effect and thus suppressing over-polishing of the silicon wafer edge.

[0054] at the same time Figure 7 By comparing the numerical values ​​of the peak values ​​of the von Mises stress curve, it can be seen from the figure that when the height difference between the silicon wafer and the inner liner is less than a certain value, the peak value of the silicon wafer surface stress begins to decrease. The planetary wheel inner liner design provided in this embodiment of the invention will advance the time when the peak value decreases, and at the same time increase the degree of weakening, thereby making the silicon wafer more uniformly stressed and the polishing and cleaning efficiency more uniform.

[0055] from Figure 8 As can be seen, the peak contact stress is mainly located at the edge of the silicon wafer. Properly controlling the abrupt changes in contact stress at the wafer edge will result in a more uniform stress distribution across the entire wafer. From... Figure 9 As can be seen, the peak contact stress initially increases and then decreases as polishing progresses. Furthermore, the planetary gear liner design provided in this embodiment of the invention allows this peak stress to enter the decreasing phase earlier, and the degree of decrease is also increased. Therefore, it can be concluded that the planetary gear liner design provided in this embodiment of the invention can effectively control the stress concentration phenomenon at the silicon wafer edge, thereby controlling the efficiency of silicon wafer edge feature removal.

[0056] Based on the above two stress analyses of silicon wafers, it can be concluded that the planetary wheel liner design provided in this embodiment of the invention can effectively control the stress on the edge of the silicon wafer, thereby controlling the edge cleaning efficiency and making the overall cleaning rate more uniform, which will increase the flatness of the silicon wafer edge.

[0057] In this simulation, the height of the inner side of the planetary wheel liner provided in this embodiment of the invention is 785 micrometers. Through the above stress analysis of the silicon wafer, it can be found that the value can change with the initial thickness of the silicon wafer. Therefore, the parameters of the planetary wheel liner can be adjusted according to the initial thickness of the silicon wafer, which will enable the stress concentration at the edge of the silicon wafer to be controlled as soon as possible, and will further improve the flatness of the edge of the silicon wafer.

[0058] It should be noted that the terms "comprising" and "having," and their variations, used in this invention document are intended to cover non-exclusive inclusion. The terms "first," "second," etc., are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence, unless explicitly indicated by the context; it should be understood that such use of data can be interchanged where appropriate. The term "one or more" depends at least in part on the context and can be used to describe features, structures, or characteristics in a singular sense, or in a plural sense to describe combinations of features, structures, or characteristics. The term "based on" can be understood as not necessarily intended to express an exclusive set of factors, but can instead, also at least in part on the context, allow for the presence of other factors that are not necessarily explicitly described. Furthermore, embodiments and features in embodiments of this invention can be combined with each other without conflict. In addition, descriptions of well-known components and technologies have been omitted in the above description to avoid unnecessarily obscuring the concepts of this invention. In the various embodiments described above, each embodiment focuses on its differences from other embodiments; similar / identical parts between embodiments can be referred to mutually.

[0059] The above description is only a preferred embodiment of the present invention. It should be noted that those skilled in the art can make several improvements and modifications without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A planetary wheel for polishing, characterized in that, include: Roulette wheel body; At least one workpiece hole penetrates the main body of the wheel; A liner is disposed on the sidewall of the workpiece hole. The liner includes an inner side and an outer side disposed radially along the workpiece hole. The inner side is used to contact the workpiece disposed in the workpiece hole, and the outer side is used to contact the sidewall of the workpiece hole. In the axial direction of the workpiece hole, the upper end of the inner side protrudes from the upper surface of the wheel body, and the lower end of the inner side protrudes from the lower surface of the wheel body or is flush with the lower surface of the wheel body. The height of the inner side is less than the initial thickness of the workpiece and greater than the final thickness of the workpiece. During the polishing process, when the workpiece is thinned to a certain thickness, the upper end of the inner side of the liner can contact and support the upper polishing pad, causing the upper polishing pad to detach from the edge of the workpiece. Then, during the period when the workpiece is further thinned to the final thickness, the upper polishing pad does not contact the edge of the workpiece and cannot continue to grind the edge of the workpiece, thereby reducing the stress concentration at the edge of the workpiece.

2. The planetary wheel for polishing according to claim 1, characterized in that, The height difference between the upper end of the inner side and the upper end of the outer side is greater than the height difference between the lower end of the inner side and the lower end of the outer side.

3. The planetary wheel for polishing according to claim 2, characterized in that, The height difference between the upper end of the inner side and the upper end of the outer side is 6-8 micrometers.

4. The planetary wheel for polishing according to claim 2, characterized in that, When the lower end of the inner side protrudes beyond the lower surface of the wheel body, the height difference between the lower end of the inner side and the lower end of the outer side is 0.5~1 micrometer.

5. The planetary wheel for polishing according to claim 1, characterized in that, The upper end of the outer side is flush with the upper surface of the wheel body, and the lower end of the outer side is flush with the lower surface of the wheel body.

6. The planetary wheel for polishing according to claim 1, characterized in that, The longitudinal section of the lining is wedge-shaped.

7. The planetary wheel for polishing according to claim 1, characterized in that, The upper and lower ends of the inner side surface are chamfered.

8. The planetary wheel for polishing according to claim 1, characterized in that, The sidewall of the workpiece hole has an internal gear, and the outer side of the liner has an external gear. The internal gear meshes with the external gear to fix the liner inside the workpiece hole.

9. The planetary wheel for polishing according to claim 1, characterized in that, The liner is fixed to the wheel body by a pin assembly.

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