Base plate assembly, lower electrode structure and semiconductor process chamber

Abstract

The utility model provides a base disc assembly, a lower electrode structure and a semiconductor process chamber, and the base disc assembly comprises a base disc which is provided with a bearing surface, and the bearing surface is provided with an annular groove; the reinforcing structure is arranged in the annular groove so as to increase the rigidity of the base disc; the center ring is arranged in the annular groove and connected with the base disc, and the top face of the center ring and the bearing face of the base disc are located in the same plane. According to the basal disc assembly, the reinforcing structure is arranged in the annular groove of the basal disc, the rigidity of the basal disc can be increased through the reinforcing structure, and the rigidity of the basal disc is improved, so that the deformation of the basal disc can be reduced or even avoided when the basal disc is assembled, the levelness of a bearing surface is ensured, and the levelness of a wafer on the bearing surface is further ensured. Moreover, during assembly, the rigidity of the base plate is improved, so that the base plate can bear higher locking torque, the base plate and the chuck are connected more tightly, and the levelness of the base plate is improved.

Description

Technical Field

[0001] This utility model relates to the field of semiconductor manufacturing, specifically to a base plate assembly, a lower electrode structure, and a semiconductor process chamber. Background Technology

[0002] As critical dimensions in the manufacturing process continue to shrink, edge etching equipment is crucial for improving product yield. Edge etching equipment uses ceramic windows to block the non-etched areas in the center of the wafer and generates plasma in the edge etching area to etch the edges of the wafer.

[0003] However, edge etching equipment has poor etching uniformity at the wafer edges, resulting in a lower yield. Utility Model Content

[0004] This invention aims to at least solve the problem of poor etching uniformity at the wafer edge in related technologies, which leads to a decrease in yield. It proposes a base disk assembly, a lower electrode structure, and a semiconductor process chamber.

[0005] To achieve the purpose of this utility model, a base plate assembly is provided, comprising: a base plate having a bearing surface, wherein an annular groove is provided on the bearing surface; a reinforcing structure disposed within the annular groove to increase the rigidity of the base plate; and a central ring disposed within the annular groove and connected to the base plate, wherein the top surface of the central ring is located in the same plane as the bearing surface of the base plate.

[0006] Optionally, the reinforcing structure includes: a plurality of reinforcing ribs, the plurality of reinforcing ribs being circumferentially spaced within the annular groove and dividing the annular groove into a plurality of sub-grooves, a sub-groove being formed between adjacent reinforcing ribs, and each sub-groove being provided with a mounting hole for connection with a chuck.

[0007] Optionally, the bottom of the central ring has multiple circumferentially spaced limiting protrusions, and adjacent limiting protrusions form a clearance groove; the limiting protrusions are configured one-to-one with the sub-grooves, and the clearance grooves are configured one-to-one with the reinforcing ribs; the limiting protrusions are located in the corresponding sub-grooves, the reinforcing ribs are located in the corresponding clearance grooves, and the reinforcing ribs and adjacent limiting protrusions are circumferentially positioned.

[0008] Optionally, the central ring is provided with a plurality of first connecting holes for fixed connection with the base plate. The plurality of first connecting holes are circumferentially spaced apart, and the minimum distance between the first connecting hole and the center of the central ring is greater than the inner diameter of the central ring. The base plate is provided with a plurality of second connecting holes corresponding to the first connecting holes, and the first connecting holes and the second connecting holes are provided in a one-to-one correspondence.

[0009] Optionally, the ratio of the width D1 of the annular groove to the radius R1 of the base disk ranges from 1 / 10 to 13 / 100.

[0010] Optionally, the ratio of the depth H1 of the sub-groove to the thickness H0 of the base plate is in the range of 4 / 15 to 2 / 5.

[0011] Optionally, the reinforcing rib has a supporting surface for supporting the central ring, the distance between the supporting surface and the bottom surface of the annular groove is H2, and the ratio of the supporting surface to the thickness H0 of the base plate is in the range of 1 / 15 to 2 / 15.

[0012] Optionally, the base plate has a connecting surface facing away from the bearing surface, the connecting surface being used to abut against the chuck, the mounting hole extending to the connecting surface, and the connecting surface being provided with a mounting groove for mounting an induction coil, the mounting groove being an annular structure.

[0013] Optionally, all the mounting holes are arranged in a circular pattern on the connecting surface, and the mounting groove is located on the outside of all the mounting holes.

[0014] Optionally, the base plate is further provided with a plurality of receiving holes for avoiding the ejector pin. The plurality of receiving holes are distributed circumferentially at intervals, and in the radial direction, the receiving holes are misaligned with the annular groove.

[0015] Optionally, all the receiving holes are circularly distributed on the bearing surface, and the annular groove is located on the outside of all the receiving holes.

[0016] According to a second aspect of the present invention, a lower electrode structure is also disclosed, comprising: a chuck and the aforementioned base plate assembly, wherein the base plate assembly is connected to the chuck.

[0017] Optionally, it also includes: an induction coil disposed between the base plate and the chuck, wherein the base plate presses the induction coil onto the chuck, and the induction coil has a ring structure.

[0018] According to a third aspect of the present invention, a semiconductor process chamber is also disclosed, comprising: a chamber body, a ceramic window, and the aforementioned lower electrode structure; the ceramic window and the lower electrode structure are located within the chamber body, the ceramic window being located above the lower electrode structure, and a support space for placing a wafer is formed between the ceramic window and the lower electrode structure.

[0019] The base plate assembly of this invention increases the rigidity of the base plate by incorporating a reinforcing structure within the annular groove. This increased rigidity reduces or even eliminates base plate deformation during assembly, ensuring the levelness of the bearing surface and consequently the levelness of the wafers mounted on it. Furthermore, the increased rigidity allows the base plate to withstand higher locking torques during assembly, resulting in a tighter connection between the base plate and the chuck, which also contributes to improving the levelness of the base plate. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of an edge etching device in related technologies;

[0021] Figure 2 This is a graph showing the etching rate of edge etching equipment in related technologies.

[0022] Figure 3 This is a schematic diagram illustrating the positional relationship between the wafer and the ceramic window in related technologies;

[0023] Figure 4 This is a schematic diagram of the structure of the base plate component in the related technology;

[0024] Figure 5 This is a schematic diagram of the base plate structure in related technologies;

[0025] Figure 6 This is a cross-sectional view of the base plate along the AA direction in the related technology;

[0026] Figure 7 This is a schematic diagram of the mounting groove for the base plate in related technologies;

[0027] Figure 8 This is a schematic diagram of the base plate assembly according to an embodiment of the present utility model;

[0028] Figure 9 This is a schematic diagram of the base disk structure of the base disk assembly according to an embodiment of the present utility model;

[0029] Figure 10 This is a schematic diagram of the connection surface of the base plate in an embodiment of the present utility model;

[0030] Figure 11 This is a schematic diagram of the base disk structure of a base disk assembly according to another embodiment of the present invention;

[0031] Figure 12 This is a schematic diagram of the connection surface of the base plate according to another embodiment of the present invention;

[0032] Figure 13 This is a BB-direction cross-sectional view of the base plate in an embodiment of the present invention;

[0033] Figure 14This is a cross-sectional view of the base plate in the CC direction of an embodiment of the present invention;

[0034] Figure 15 This is a graph showing the etching rate of a semiconductor process apparatus for a base disk assembly using embodiments of the present invention.

[0035] List of reference numerals in the attached diagram:

[0036] 10. Base plate; 11. Bearing surface; 12. Annular groove; 121. Sub-groove; 1211. First sub-groove; 1212. Second sub-groove; 13. Mounting hole; 14. Second connecting hole; 15. Connecting surface; 16. Mounting groove; 17. Receiving hole; 20. Reinforcing structure; 21. Reinforcing rib; 211. Supporting surface; 30. Central ring; 31. Limiting protrusion; 311. First protrusion; 312. Second protrusion; 32. Clearance groove; 33. First connecting hole. Detailed Implementation

[0037] To enable those skilled in the art to better understand the technical solution of this utility model, the base plate assembly, lower electrode structure, and semiconductor process chamber provided by this utility model will be described in detail below with reference to the accompanying drawings.

[0038] As critical dimensions in the manufacturing process continue to shrink, edge etching equipment is crucial for improving product yield. Edge etching equipment uses ceramic windows to block the non-etched areas in the center of the wafer and generates plasma in the edge etching area to etch the edges of the wafer.

[0039] However, edge etching equipment has poor etching uniformity at the wafer edges, resulting in a lower yield.

[0040] Specifically, such as Figure 1 As shown, the edge etching machine includes: a process chamber 1' and a lower electrode structure disposed within the process chamber 1', and a ceramic window 2' located above the lower electrode. The lower electrode structure includes: a chuck 3' and a base disk assembly 4' disposed above and fixedly connected to the chuck 3'. The wafer 5' is located on the base disk assembly 4'. During the etching process, under the action of an alternating electric field, the reactive gas is dissociated and plasma is generated. The ceramic window 2' blocks the non-etched area in the middle of the wafer 5', preventing the plasma from entering the non-etched area in the middle of the wafer 5', and allowing it to enter the unblocked portion and the edge area near the unblocked portion, thereby etching the edge of the wafer 5'.

[0041] like Figure 2 As shown, taking the etching rate map at a distance of 0.6 mm from the 5' edge of the wafer as an example, the following is used: Figure 1 The edge etching machine using the mid-assembly method has an eccentricity of 18.7% and an etching rate of [missing information]. Not only is the eccentricity large, but the etching rate is also slow.

[0042] Analysis revealed that the main reasons for the poor uniformity were threefold:

[0043] First, the levelness of wafer 5' is poor; that is, during the manufacturing process, wafer 5' is not perfectly level, but ceramic window 2' is level. Figure 3 As shown, this results in the wafer 5' and ceramic window 2' not being parallel, forming an angle. Consequently, the spacing between wafer 5' and ceramic window 2' varies in different areas. In other words, the uneven levelness of wafer 5' causes it to be higher at one end and lower at the other in the radial direction. The higher end of wafer 5' is closer to ceramic window 2' with a smaller gap, making it difficult for plasma to enter between them. Therefore, there is less plasma between the higher end of wafer 5' and ceramic window 2', resulting in a slower etching rate. Conversely, the lower end of wafer 5' is farther from ceramic window 2' with a larger gap, allowing plasma to enter between them more easily. Therefore, there is more plasma entering between the lower end of wafer 5' and ceramic window 2', resulting in a faster etching rate. Ultimately, this leads to poor etching uniformity.

[0044] Further analysis revealed that the base plate 6' had high parallelism during manufacturing, but a change in levelness occurred after assembly. After extensive research, it was found that the reason for this phenomenon was that the base plate 6' was not strong enough and would deform during assembly, thus causing a change in the levelness of the bearing surface of the base plate 6'.

[0045] like Figure 4 and Figure 5 As shown, the base plate assembly 4' includes a base plate 6' and a central ring 7' disposed on the base plate 6'. The base plate 6' has an annular groove 8' for mounting the central ring, and the bottom of the annular groove 8' has 12 mounting holes 9' spaced circumferentially for connection with the chuck 3' below the base plate 6'. During assembly, a bolt is installed in each mounting hole 9', and the base plate 6' is fixedly connected to the chuck 3' by the 12 bolts.

[0046] In order to be fixedly connected to the base plate 6', the central ring 7' is also provided with three first connecting holes 10', and the annular groove 8' is also provided with three second connecting holes 11' corresponding to the first connecting holes 10', so that the fixed connection between the central ring 7' and the base plate 6' is achieved by three bolts.

[0047] Normally, such as Figure 5 As shown, the width of the annular groove 8', D10, is 22.5 mm, and the radius of the base plate 6', R10, is 146.2 mm. The ratio of D10 to R10 is approximately 3 / 20. Figure 6As shown, the depth of the annular groove 8' is H10 = 7 mm, and the depth of the base plate 6' is H20 = 15 mm, with H10 / H20 being 7 / 15. Research revealed that the dimensions of the annular groove 8' reduce the overall rigidity of the base plate 6'. This causes deformation of the base plate 6' under the tightening force when the bolts are tightened, resulting in a decrease in the levelness of the bearing surface, and ultimately, a decrease in the levelness of the wafer 5' placed on the bearing surface.

[0048] Secondly, uneven radio frequency energy results in poor etching uniformity. An induction coil 12' is placed between the base plate 6' and the chuck 3'. For example... Figure 7 As shown, the base plate 6' facing the chuck 3' has a mounting groove 13' for accommodating the induction coil 12'. The mounting groove 13' is an arc-shaped structure and consists of multiple grooves, which are circumferentially spaced and form a fitted circle. These grooves are alternately arranged with mounting holes 9'. Correspondingly, the induction coil 12' includes multiple arc-shaped segments, each corresponding to a mounting groove 13'. Each arc-shaped segment is located within its corresponding groove, and all arc-shaped segments are electrically connected.

[0049] As can be seen, after assembling the induction coil 12', each arc segment is located between two adjacent mounting holes 9'. When the base plate 6' is connected to the chuck 3' by bolts, the induction coil 12' can be fully pressed down. However, the segmented induction coil 12' has poor conductivity and poor uniformity of RF feed energy, which not only significantly affects the etching uniformity but also significantly affects the etching rate.

[0050] The reason for using a multi-segment induction coil 12' in related technologies is that the base 6' has low rigidity. If a complete ring-shaped induction coil 12' were used, the bolt tightening torque connecting the base 6' and the chuck 3' would need to be increased to 2 N*M to ensure sufficient compression of the induction coil 12'. However, the base 6' has a maximum rigidity that can only achieve a tightening torque of 1 N*M per circumference. Increasing the tightening torque would cause significant deformation at the edges of the base 6', which would severely affect the horizontality of the wafer 5' and deteriorate the uniformity of edge etching.

[0051] Furthermore, the improper design of the 14' position of the ejector pin will not only cause the 5' of the wafer to shift. For example... Figure 1As shown, ejector pin 14' needs to pass through both the base ring and the center ring 7' simultaneously. When ejector pin 14' is retracted, the distance between the top of ejector pin 14' and the upper surface of the base plate 6' is only 1mm. It is easy to bump ejector pin 14' when removing or installing the center ring 7'. Therefore, when removing or installing the center ring 7', ejector pin 14' is usually pulled out first, and then ejector pin 14' is inserted into ejector pin hole 15'. Frequent insertion and removal of ejector pin 14' affects its stability, causing the wafer 5' to shift position and affecting the uniformity of edge etching. If the shift is too large, it can cause scratching and generate impurity particles, thus contaminating the wafer 5'. Furthermore, if ejector pin 14' is unstable, adjusting it requires removing components such as the center ring 7' and the base plate 6', making maintenance more difficult.

[0052] In addition, when loosening or tightening the screw between the center ring 7' and the base plate 6', aluminum shavings inside the screw may fall off. Since the bolt center of the existing solution is provided with a pin hole 15' to avoid the pin 14', the aluminum shavings falling into the through hole will rub against the pin 14' and the hole wall, which will accelerate the generation of impurity particles in the chamber, thereby contaminating the wafer 5'.

[0053] Therefore, in order to solve the above-mentioned technical problems, such as Figure 8 As shown, this utility model discloses a base plate assembly, including: a base plate 10, a reinforcing structure 20, and a central ring 30. The base plate 10 has a bearing surface 11, on which an annular groove 12 is provided; the reinforcing structure 20 is disposed in the annular groove 12 to increase the rigidity of the base plate 10; the central ring 30 is disposed in the annular groove 12 and connected to the base plate 10, and the top surface of the central ring 30 is located in the same plane as the bearing surface 11 of the base plate 10.

[0054] The base plate assembly of this invention increases the rigidity of the base plate 10 by providing a reinforcing structure 20 within the annular groove 12. This increased rigidity reduces or even eliminates deformation of the base plate 10 during assembly, ensuring the levelness of the bearing surface 11 and consequently the levelness of the wafers mounted thereon. Furthermore, the increased rigidity of the base plate 10 allows it to withstand higher locking torques during assembly, resulting in a tighter connection between the base plate 10 and the chuck, further enhancing the levelness of the base plate 10.

[0055] Specifically, such as Figure 9 As shown, the reinforcing structure 20 includes a plurality of reinforcing ribs 21. The plurality of reinforcing ribs 21 are circumferentially spaced within the annular groove 12, and the reinforcing ribs 21 divide the annular groove 12 into a plurality of sub-grooves 121. A sub-groove 121 is formed between adjacent reinforcing ribs 21, and each sub-groove 121 is provided with a mounting hole 13 for connection with a chuck.

[0056] During assembly, bolts are inserted into the mounting holes 13 of the sub-slot 121, and the base plate 10 is fixedly connected to the chuck using bolts. Since a sub-slot 121 is formed between adjacent reinforcing ribs 21, in other words, reinforcing ribs 21 are also provided between adjacent sub-slots 121, the actual thickness at the location where the reinforcing ribs 21 are provided is increased. Therefore, when fastened with bolts, the presence of reinforcing ribs 21 increases the rigidity of the base plate 10 near the bolts, making it less prone to deformation under the bolt tightening torque, thereby ensuring the levelness of the bearing surface 11 of the base plate 10.

[0057] like Figure 8 As shown, the bottom of the central ring 30 has multiple circumferentially spaced limiting protrusions 31, and adjacent limiting protrusions 31 form a clearance groove 32; the limiting protrusions 31 are arranged in a one-to-one correspondence with the sub-grooves 121, and the clearance grooves 32 are arranged in a one-to-one correspondence with the reinforcing ribs 21. The limiting protrusions 31 are located in the corresponding sub-grooves 121, and the reinforcing ribs 21 are located in the corresponding clearance grooves 32. The reinforcing ribs 21 and the adjacent limiting protrusions 31 are in a circumferentially limiting fit.

[0058] Multiple circumferentially spaced limiting protrusions 31 are provided at the bottom of the central ring 30. The limiting protrusions 31 and the reinforcing ribs 21 can achieve circumferential limiting cooperation, which makes it easier to install and position the central ring 30 and the base plate 10, thereby improving assembly efficiency.

[0059] like Figure 8 As shown, the central ring 30 is provided with a plurality of first connecting holes 33 for fixed connection with the base plate 10. The plurality of first connecting holes 33 are circumferentially spaced, and the minimum distance between the first connecting hole 33 and the center of the central ring 30 is greater than the inner diameter of the central ring 30. Correspondingly, the base plate 10 is provided with a plurality of second connecting holes 14 corresponding to the first connecting holes 33, with each first connecting hole 33 and second connecting hole 14 arranged in a one-to-one correspondence. That is to say, with... Figure 4 Compared to the first connecting hole 10', the central ring 7' in the related technology shown is as follows: Figure 8 As shown, the first connecting hole 33 is completely inside the central ring 30 and does not form an inward protrusion on the inner peripheral wall of the central ring 30, thus saving more space.

[0060] During assembly, bolts are inserted into the first connecting hole 33 and threaded into the second connecting hole 14, thereby fixing the center ring 30 to the base plate 10. It should be noted that when subjected to horizontal external forces, without the cooperation of the reinforcing rib 21 and the limiting protrusion 31, the bolts would lock onto the base plate 10 due to excessive horizontal stress, thus affecting the service life of the components. However, by using the axial upper limit cooperation between the reinforcing rib 21 and the limiting protrusion 31, the reinforcing rib 21 and the limiting protrusion 31 effectively distribute the horizontal stress borne by the bolts, thereby preventing the bolts from locking onto the base plate 10 and improving the service life of the components.

[0061] Specifically, the plurality of limiting protrusions 31 include: a plurality of first protrusions 311 and a plurality of second protrusions 312, with a second protrusion 312 disposed between adjacent first protrusions 311; a first connecting hole 33 is disposed in a one-to-one correspondence with the first protrusions 311, and the first connecting hole 33 passes through the corresponding first protrusion 311. The plurality of sub-slots 121 include: a plurality of first sub-slots 1211 that match the first protrusions 311 and a plurality of second sub-slots 1212 that match the second protrusions 312; the first sub-slots 1211 and the first protrusions 311 are disposed in a one-to-one correspondence, the second sub-slots 1212 and the second protrusions 312 are disposed in a one-to-one correspondence, and both the first sub-slots 1211 and the second sub-slots 1212 are provided with mounting holes 13, and the first sub-slots 1211 are also provided with second connecting holes 14.

[0062] For example, such as Figure 8 As shown, the central ring 30 has three first connecting holes 33, three first protrusions 311, and six second protrusions 312, with two second protrusions 312 positioned between two adjacent first protrusions 311. Correspondingly, there are nine reinforcing ribs 21, as shown in the diagram. Figure 9 The arrangement shown forms three first sub-slots 1211 and six second sub-slots 1212, with two second sub-slots 1212 between each pair of adjacent first sub-slots 1211. The length of the first protrusion 311 is greater than the length of the second protrusion 312; therefore, the length of the first sub-slot 1211 is greater than the length of the second sub-slot 1212. There are twelve mounting holes 13, with two mounting holes 13 in each first sub-slot 1211 and a second connecting hole 14 between the two mounting holes 13. Each second sub-slot 1212 has only one mounting hole 13.

[0063] exist Figure 11 and Figure 12 In the illustrated embodiment, there are three first connecting holes 33 on the central ring 30, but this is not limiting. Figure 11 and Figure 12In another embodiment shown, there are six first connecting holes 33 and six second connecting holes 14, and twelve mounting holes 13. Six reinforcing ribs 21 divide the annular groove 12 into six sub-grooves 121 of equal length. Each sub-groove 121 contains two mounting holes 13 and one second connecting hole 14. The second connecting hole 14 is located between the two mounting holes 13 and penetrates the base plate 10, allowing bolts to be fixed to the chuck below the base plate 10. This structure increases the reliability of the connection between the center ring 30 and the base plate 10. By increasing the number of second connecting holes 14 and ensuring they penetrate the base plate 10, the stability of the center ring 30 assembly is enhanced, effectively preventing the center ring 30 from deforming and protruding from the surface of the base plate 10 due to thermal expansion, thus ensuring the wafer's levelness. Simultaneously, because more bolts connect the base plate 10 and the chuck, the contact between the induction coil and the base plate 10 and the chuck is tighter, reducing RF loss and increasing the etching rate. Therefore, this structure also falls within the protection scope of this utility model.

[0064] like Figure 9 As shown, the width D1 of the annular groove 12 ranges from 14 to 18 mm, and the radius R1 of the base disk 10 is 146.2 mm. That is, the range of D1 / R1 is 1 / 10 to 13 / 100. It can be seen that compared with related technologies, the base disk 10 of this utility model has a smaller width than the annular groove 12. Due to the reduced width of the annular groove 12, the overall rigidity of the base disk 10 is improved. Combined with the reinforcing rib 21, the rigidity of the base disk 10 can be further improved, thereby reducing the deformation of the base disk 10 and ensuring the levelness of the wafer.

[0065] like Figure 13 As shown, the depth H1 of the sub-groove 121 (that is, the distance from the bottom surface of the annular groove 12 to the bearing surface 11) ranges from 4 to 6 mm, and the thickness H0 of the base plate 10 is 15 mm. That is to say, the range of H1 / H0 is 4 / 15 to 2 / 5. It can be seen that compared with related technologies, the base plate 10 of this utility model has less depth than the annular groove 12. Because the depth of the annular groove 12 is reduced, the thickness of the base plate 10 below the annular groove 12 is correspondingly increased. With the help of the reinforcing rib 21, the rigidity of the base plate 10 can be further improved, thereby reducing the deformation of the base plate 10 and ensuring the levelness of the wafer.

[0066] like Figure 14As shown, the reinforcing rib 21 has a support surface 211 for supporting the central ring 30. By providing the support surface 211, the central ring 30 can be supported at the bottom during assembly, thereby distributing the force on the central ring 30 and preventing deformation of the central ring 30. It can be understood that the distance between the support surface 211 and the bottom surface of the annular groove 12 is H2, and the value of H2 ranges from 1 to 2 mm, so as to accommodate the central ring 30. The thickness H0 of the base plate 10 is 15 mm, that is, the range of H2 / H0 is 1 / 15 to 2 / 15.

[0067] It should be noted that if H1 / H0, D1 / R1, and H2 / H0 are greater than the given range, the stiffness of the base plate 10 will not be significantly improved, failing to achieve the expected effect, and the adjustable locking torque range will be smaller. If H1 / H0 is less than the given range, the width of the annular groove 12 will be too narrow, affecting the size of the mounting hole 13 and the second connecting hole 14, causing the size of the mounting hole 13 and the second connecting hole 14 to shrink, which in turn reduces the bolt size, thus reducing the bolt strength and causing a decrease in locking torque. If D1 / R1 and H2 / H0 are less than the given range, the size of the central ring 30 will be limited, thus reducing the strength of the central ring 30. The reduced strength of the central ring 30 will cause it to bulge out of the bearing surface 11 of the base plate 10 after thermal expansion, affecting the wafer's levelness, which in turn affects the edge etching uniformity, and also reduces the allowable processing error range of the central ring 30, increasing the processing difficulty and thus increasing costs.

[0068] By reducing the width and depth of the annular groove 12 and cooperating with the reinforcing rib 21, the rigidity of the base disk 10 can be significantly improved while ensuring the strength of the central ring 30 and the bolts. This makes the levelness of the base disk 10 under a locking torque of 2 N*m better than that under a locking torque of 1 N*m in related technologies. As a result, the levelness of the wafer placed on the base disk 10 is optimized and the etching uniformity is improved.

[0069] like Figure 10 and Figure 13 As shown, the base plate 10 has a connecting surface 15 facing away from the bearing surface 11. The connecting surface 15 is used to abut against the chuck. The mounting hole 13 extends to the connecting surface 15. A mounting groove 16 for mounting an induction coil is provided on the connecting surface 15. The mounting groove 16 has a ring structure. By providing the mounting groove 16 on the connecting surface 15 of the base plate 10, and the mounting groove 16 has a complete ring structure, an induction coil with a complete ring structure can be set in the mounting groove 16. Compared with segmented induction coils, the radio frequency energy fed into the edge of the base plate 10 is more uniform due to the use of an induction coil with a complete ring structure, thereby effectively improving the edge etching uniformity.

[0070] It should be noted that the mounting groove 16 on the base plate 10 of this invention can be configured as a complete annular structure because the rigidity of the base plate 10 is significantly improved by setting the reinforcing rib 21 and reducing the depth and width of the sub-groove 121. Therefore, the base plate 10 can withstand a larger locking torque without deformation. In other words, the base plate 10 maintains a high degree of levelness under a locking torque of 2 N*m. Under a larger locking torque, the base plate 10 can apply a greater downward pressure to the induction coil, making the contact between the induction coil, which has a complete annular structure, and the base plate 10 and the chuck below it tighter, ensuring the reliability of the assembly, reducing radio frequency loss, and improving the etching rate.

[0071] like Figure 10 As shown, all mounting holes 13 are circularly distributed on the connecting surface 15, and mounting grooves 16 are located on the outside of all mounting holes 13. By placing the mounting grooves 16 on the outside of the mounting holes 13, that is, by placing the induction coil on the outside of the mounting holes 13, the induction coil is expanded outward compared with related technologies. Therefore, the conductivity is improved, the ability to conduct radio frequency energy is stronger, energy loss is reduced, and the etching rate is increased.

[0072] The base plate assembly of this invention improves the etching uniformity and etching rate of the edge etching machine, reduces the risk of etching uniformity deterioration, and is conducive to improving product yield.

[0073] like Figure 9 and Figure 10 As shown, the base plate 10 is also provided with multiple receiving holes 17 for avoiding ejector pins. These receiving holes 17 are spaced apart circumferentially, and radially offset from the annular groove 12. In other words, the receiving holes 17 of this invention are only provided on the base plate 10, avoiding the annular groove 12 and thus the central ring 30. In this way, the fixing screws of the central ring 30 and the base plate 10 are far from the ejector pins. When installing or removing the central ring 30, it is not necessary to insert or remove the ejector pins, thus greatly reducing the loosening of the ejector pins caused by insertion or removal, thereby keeping the ejector pins stable and ensuring the levelness of the wafer. Furthermore, aluminum shavings generated during the installation or removal of the central ring 30 will not enter the receiving holes 17 of the three pins. They can be cleaned by wiping with a lint-free cloth containing isopropyl alcohol and blowing with a nitrogen gun, thus ensuring the cleanliness of the process chamber and reducing the risk of wafer contamination.

[0074] For example, such as Figure 9 and Figure 10 As shown, all the receiving holes 17 are circularly distributed on the bearing surface 11, and the annular groove 12 is located on the outside of all the receiving holes 17.

[0075] According to a second aspect of this utility model, a lower electrode structure is also disclosed, comprising: a chuck and the aforementioned base plate assembly, wherein the base plate assembly is connected to the chuck. The lower electrode structure of this utility model, by providing a reinforcing structure 20 within the annular groove 12 of the base plate 10, increases the rigidity of the base plate 10. By increasing the rigidity of the base plate 10, deformation of the base plate 10 can be reduced or even avoided during assembly, thereby ensuring the levelness of the bearing surface 11 and consequently the levelness of the wafer on it. Furthermore, during assembly, due to the increased rigidity of the base plate 10, it can withstand a higher locking torque, resulting in a tighter connection between the base plate 10 and the chuck, which also helps to improve the levelness of the base plate 10.

[0076] The lower electrode structure also includes an induction coil, which is disposed between the base plate 10 and the chuck. The base plate 10 presses the induction coil onto the chuck, and the induction coil has a ring structure. By setting a complete ring structure in the induction coil, compared with a segmented induction coil, the radio frequency energy fed into the edge of the base plate 10 is more uniform due to the use of a complete ring structure in the induction coil, thereby effectively improving the edge etching uniformity.

[0077] According to a third aspect of the present invention, a semiconductor process chamber is also disclosed, comprising: a chamber body, a ceramic window, and the aforementioned lower electrode structure; the ceramic window and the lower electrode structure are located within the chamber body, the ceramic window being located above the lower electrode structure, and a support space for placing a wafer is formed between the ceramic window and the lower electrode structure.

[0078] For example, such as Figure 15 As shown, taking the etching rate diagram at a distance of 0.6 mm from the wafer edge as an example, the process chamber of the base disk assembly in the above embodiment has an eccentricity of only 8.93%, while the etching rate is... and Figure 2 Compared with related technologies, the eccentricity was reduced by 9.77%, while the etching rate was increased by 10%, and both the etching uniformity and etching rate were significantly improved.

[0079] It is understood that the above embodiments are merely exemplary implementations used to illustrate the principles of this utility model, and the utility model is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and essence of this utility model, and these modifications and improvements are also considered to be within the protection scope of this utility model.

Claims

1. A base disk assembly, characterized in that, include: The base plate (10) has a bearing surface (11) on which an annular groove (12) is provided; A reinforcing structure (20) is provided within the annular groove (12) to increase the rigidity of the base plate (10); A central ring (30) is disposed in the annular groove (12) and connected to the base plate (10), and the top surface of the central ring (30) and the bearing surface (11) of the base plate (10) are located in the same plane.

2. The base disk assembly according to claim 1, characterized in that, The reinforcing structure (20) includes: Multiple reinforcing ribs (21) are circumferentially spaced within the annular groove (12) and divide the annular groove (12) into multiple sub-grooves (121). A sub-groove (121) is formed between adjacent reinforcing ribs (21), and each sub-groove (121) is provided with a mounting hole (13) for connection with a chuck.

3. The base disk assembly according to claim 2, characterized in that, The bottom of the central ring (30) has a plurality of circumferentially spaced limiting protrusions (31), and an avoidance groove (32) is formed between adjacent limiting protrusions (31). The limiting protrusion (31) is provided in a one-to-one correspondence with the sub-groove (121), the clearance groove (32) is provided in a one-to-one correspondence with the reinforcing rib (21), the limiting protrusion (31) is located in the corresponding sub-groove (121), the reinforcing rib (21) is located in the corresponding clearance groove (32), and the reinforcing rib (21) and the adjacent limiting protrusion (31) are in a circumferential limiting fit.

4. The base disk assembly according to claim 1, characterized in that, The central ring (30) is provided with a plurality of first connecting holes (33) for fixed connection with the base plate (10). The plurality of first connecting holes (33) are circumferentially spaced. The minimum distance between the first connecting hole (33) and the center of the central ring (30) is greater than the inner diameter of the central ring (30). The base plate (10) is provided with a plurality of second connection holes (14) corresponding to the first connection hole (33), and the first connection hole (33) and the second connection hole (14) are provided in a one-to-one correspondence.

5. The base disk assembly according to claim 1, characterized in that, The ratio of the width D1 of the annular groove (12) to the radius R1 of the base plate (10) ranges from 1 / 10 to 13 / 100.

6. The base disk assembly according to claim 2, characterized in that, The ratio of the depth H1 of the sub-groove (121) to the thickness H0 of the base plate (10) ranges from 4 / 15 to 2 / 5.

7. The base disk assembly according to claim 2, characterized in that, The reinforcing rib (21) has a supporting surface (211) for supporting the central ring (30), the distance between the supporting surface (211) and the bottom surface of the annular groove (12) is H2, and the ratio of the supporting surface (211) to the thickness H0 of the base plate (10) is in the range of 1 / 15 to 2 / 15.

8. The base disk assembly according to claim 2, characterized in that, The base plate (10) has a connecting surface (15) facing away from the bearing surface (11), the connecting surface (15) is used to abut against the chuck, the mounting hole (13) extends to the connecting surface (15), and the connecting surface (15) is provided with a mounting groove (16) for mounting an induction coil, the mounting groove (16) is annular.

9. The base disk assembly according to claim 8, characterized in that, All the mounting holes (13) are circularly distributed on the connecting surface (15), and the mounting groove (16) is located outside all the mounting holes (13).

10. The base disk assembly according to claim 1, characterized in that, The base plate (10) is also provided with a plurality of receiving holes (17) for accommodating ejector pins. The plurality of receiving holes (17) are distributed circumferentially at intervals, and in the radial direction, the receiving holes (17) are misaligned with the annular groove (12).

11. The base disk assembly according to claim 10, characterized in that, All the receiving holes (17) are circularly distributed on the bearing surface (11), and the annular groove (12) is located on the outside of all the receiving holes (17).

12. A lower electrode structure, characterized in that, include: The chuck and the base disk assembly according to any one of claims 1 to 11, wherein the base disk assembly is connected to the chuck.

13. The lower electrode structure according to claim 12, characterized in that, Also includes: An induction coil is disposed between the base plate (10) and the chuck, and the base plate (10) presses the induction coil onto the chuck. The induction coil has a ring structure.

14. A semiconductor process chamber, characterized in that, include: The chamber body, the ceramic window, and the lower electrode structure as described in claim 12 or 13; the ceramic window and the lower electrode structure are located within the chamber body, the ceramic window is located above the lower electrode structure, and a support space for placing a wafer is formed between the ceramic window and the lower electrode structure.

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