Disc type stirring device and electroplating bath

Abstract

The invention provides a disc-type stirring device and an electroplating bath, the stirring device comprises an inverted disc-shaped stirring plate, the stirring plate comprises an upward raised stirring area and a chassis, the stirring area comprises a skeleton structure accounting for 35-45% of the area of the stirring area, the skeleton structure comprises a transverse skeleton and a longitudinal skeleton which are intersected, and the transverse skeleton is provided with a fin-type structure; the stirring area further comprises middle flow uniformizing openings and side flow uniformizing openings, the middle flow uniformizing openings are formed in the areas defined by the adjacent transverse frameworks and the longitudinal frameworks, and the side flow uniformizing openings are continuously formed in the side of the upper surface of the stirring area, the side face of the stirring area and the surface of the base plate. By installing the device provided by the invention, the diffusion of the electroplating liquid into the groove can be accelerated, the concentration difference of the electroplating liquid at the center and the edge of the wafer is reduced, and bubbles generated by hydrogen precipitation under metal electroplating relative to hydrogen overpotential are eliminated, so that the material exchange in the groove is accelerated, and the deposition of copper ions is promoted; the thickness of the electroplated film on each part of the whole wafer is uniform and consistent, and the filling efficiency in the groove is closer to defect-free filling.

Description

Technical Field

[0001] The present invention relates to the technical field of electroplating devices, and in particular to a disc stirring device and an electroplating tank comprising the disc stirring device. Background Art

[0002] Damascus or dual-damascene structure horizontal electroplating copper technology for integrated circuit manufacturing of high-end chips is the basis of advanced metal interconnection. Damascus structure has step-shaped grooves and holes. The key to developing high-end horizontal electroplating process for such structure is to accelerate the diffusion of metal ions under specific stirring conditions by using different additive ratios in the solution, i.e., accelerator, leveler, brightener and wetting agent and their relative diffusion / adsorption characteristics, etc., to eliminate the concentration difference of electroplating components in different areas of the wafer surface, such as the center and the edge, eliminate bubbles, improve uniformity, and produce copper deposition without holes, gaps and seams.

[0003] Therefore, the effective diffusion, exchange and deposition of horizontal plating solution in the Damascus or dual Damascus structure of high-end chips is to improve the diffusion and uniform distribution of the plating solution under the premise of ensuring the quality of plating. These can be improved and enhanced by combining different stirring mechanisms and stirring methods in the plating chamber. However, the existing plating solution stirring mechanism structure needs to be optimized, and the stirring method needs to be further improved and enhanced. Summary of the invention

[0004] In view of the defects in the prior art, the purpose of the present invention is to provide an electroplating stirring device. During the wafer electroplating process, a unique cavity grid disk liquid stirring device is implemented to apply controlled physical stirring to the electroplating liquid, and the cathode liquid on the wafer surface is appropriately diverted and uniformly flowed. The electroplating liquid moves along with the uniform flow of the stirring device (it can also cooperate with the horizontal rotation of the wafer), which will accelerate its diffusion into the grooves on the wafer surface, reduce the electroplating liquid concentration difference between the center and the edge of the wafer, and eliminate bubbles generated by hydrogen precipitation under metal electroplating relative to the hydrogen overpotential, thereby accelerating the material exchange in the groove and promoting the deposition of copper ions, so as to achieve uniform thickness of the electroplated film at various locations on the entire wafer and a defect-free filling with a closer filling efficiency in the groove.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0006] According to a first aspect of the present invention, there is provided a disc-type stirring device, comprising a stirring plate in the shape of an inverted disc, wherein the stirring plate comprises a stirring zone protruding upward and a bottom plate extending outward from the bottom of the stirring zone, wherein the stirring zone comprises an upper surface of the stirring zone and a side surface of the stirring zone;

[0007] The stirring zone includes a skeleton structure, the area of ​​the skeleton structure accounts for 35% to 45% of the area of ​​the stirring zone, the skeleton structure includes a plurality of intersecting transverse skeletons and longitudinal skeletons, and a fin structure is arranged on the transverse skeleton;

[0008] The stirring zone also includes a uniform flow port, which includes a middle uniform flow port and an edge uniform flow port. The middle uniform flow port is opened in the area enclosed by adjacent transverse frames and adjacent longitudinal frames, and the edge uniform flow ports are continuously opened on the edge of the upper surface of the stirring zone, the side of the stirring zone, and the position of the bottom plate surface close to its connection with the bottom of the stirring zone.

[0009] In actual use, the disc stirring device provided by the technical solution is installed in the plating chamber of the electroplating equipment. During electroplating, it will be in a rotating state. When the plating solution is circulated and input upward from the lower center position of the plating chamber, the plating solution will be broken up by the transverse and longitudinal skeletons of the stirring zone and pass through the uniform flow port, thereby making the plating solution more evenly distributed; at the same time, a fin structure is provided on the transverse skeleton, which can drive the plating solution to move upward so that the plating solution reaches the surface of the wafer. At the same time, the design also enables the plating solution to pass through the gaps formed between the fin structures and be distributed at different positions of the skeleton, thereby accelerating the convection distribution between the effective chemical components of the plating solution on the wafer surface and eliminating hydrogen bubbles generated by overpotential as the stirring occurs; further, the edge uniform flow port is opened to the side and chassis of the stirring zone, so that the edge of the skeleton is openly distributed, thereby enabling the edge plating solution to flow out in a controlled manner, reducing the thickness of the coating at the edge of the wafer and reducing the edge effect of wafer plating.

[0010] Preferably, the fin-like structure is in a trapezoidal shape, with a height between 1 and 3 mm, and a nearly V-shaped opening is formed between adjacent fin-like structures.

[0011] In the present technical solution, by adopting the above-mentioned structural design, it is ensured that the liquid will not be completely drained from the center to the edge by the movement of the skeleton, so that the plating liquid will move upward along the fin structure. At the same time, through the nearly V-shaped opening, the plating liquid is left at different positions of the skeleton, which will accelerate the convection distribution between the effective chemical components of the plating liquid on the wafer surface and eliminate the hydrogen bubbles generated by the overpotential as the stirring occurs.

[0012] Preferably, the density of the nearly V-shaped openings is greater at positions closer to the center of the upper surface of the stirring zone, and is lower at positions farther away from the center of the upper surface of the stirring zone.

[0013] In this technical solution, by adopting the above-mentioned structural design, it is effectively ensured that the material distribution in the diffusion layer of the plating solution from the center of the wafer to the edge of the wafer is more uniform, and the concentration difference between the center of the wafer and the edge of the wafer is reduced. It should be noted that the density of the near-V-shaped openings in this technical solution increases at a position close to the center of the upper surface of the stirring zone. This increase can be caused by the gap between adjacent near-V-shaped openings getting smaller and smaller as they get closer to the center of the upper surface of the stirring zone, or it can be caused by zoning the stirring zone in advance, with the gap between the near-V-shaped openings in the zone being the same, but the gap between adjacent near-V-shaped opening zones getting smaller and smaller as they get closer to the center of the upper surface of the stirring zone.

[0014] Preferably, the distance between adjacent transverse frames is between 1 and 5 mm, and the distance between adjacent longitudinal frames is between 40 and 80 mm.

[0015] In the present technical solution, by adopting the above-mentioned structural design, the flatness of the liquid surface of the electroplating solution and the uniform distribution of the components of the electroplating solution are further improved.

[0016] Preferably, the opening widths of the middle flow uniformity opening and the side flow uniformity opening are between 1 and 2 mm, and the opening widths of the middle flow uniformity opening and the side flow uniformity opening are uniform and consistent.

[0017] In the present technical solution, by adopting the above-mentioned structural design, the distribution of the electroplating solution can be made more uniform, and the design also makes the edge of the skeleton 100% open distribution.

[0018] According to a second aspect of the present invention, there is provided an electroplating tank comprising an electroplating chamber and a disc stirring device as described in any one of the above items, wherein the disc stirring device is horizontally arranged in the electroplating chamber.

[0019] Preferably, it also includes a driving device, which is connected to the disc stirring device and can drive the disc stirring device to rotate at a preset speed.

[0020] In this technical solution, by adopting the above-mentioned structural design, the user can adjust the rotation speed of the disc stirring device according to actual needs to improve the thickness distribution of the metal deposition layer on the wafer surface, eliminate bubbles, and improve groove filling defects.

[0021] Preferably, the preset speed is between 60 and 120 revolutions per minute, and the rotation direction is clockwise.

[0022] In the present technical solution, by adopting the above-mentioned design, the additive in the liquid medicine is evenly distributed, which can further improve the uniformity and filling effect of the wafer.

[0023] Preferably, a liquid inlet diversion device is provided at the bottom center of the electroplating chamber, and the liquid inlet diversion device includes a liquid inlet portion and a diversion portion located above the liquid inlet portion, and a plurality of rows of diversion holes are evenly provided on the diversion portion along its extension direction.

[0024] In the present technical solution, by using a liquid inlet diversion device, the electroplating solution can flow evenly to the cavity, and different positions of the electroplating cavity are evenly filled with the electroplating solution, so that the chemical components in the electroplating solution are evenly distributed on the surface of the wafer, reducing the concentration difference of the chemical components inside the electroplating cavity, thereby improving the uniformity of the metal deposition thickness of the entire wafer.

[0025] Preferably, the liquid inlet volume of the liquid inlet diversion device is 25 to 35 liters per minute.

[0026] In the present technical solution, by adopting the above-mentioned structural design, the groove filling can be further improved, thereby obtaining good uniformity of wafer electroplating.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] 1. The present invention provides a disc stirring device with a special structural design, which accelerates the movement of chemical components in the electroplating solution, thereby reducing the thickness of the diffusion layer, promoting the uniformity of ion density and accelerating diffusion; the horizontal and vertical frame straight-edge openings in the stirring device are used to level the cathode liquid surface of the electroplating chamber, effectively ensuring the consistency of concentration at various parts of the wafer surface; the fin structure on the frame promotes the upward movement of the electroplating solution to reach the wafer surface, effectively reducing the thickness of the diffusion layer of the electroplating solution.

[0029] 2. The present invention can further design the gaps between the fin structures on the skeleton structure to be V-shaped openings and partition them to adopt different density designs (more openings at the stirring center and fewer openings at the edge), thereby reducing the difference in the amount of plating solution at the center and edge of the wafer.

[0030] 3. The present invention effectively ensures that the concentration and liquid level of the plating solution at various positions on the wafer surface are consistent through the combination of the above designs, and the concentration difference between the cavity plating solution and the wafer surface / from the center to the edge of the wafer surface is minimized as much as possible, so that chemical and ion components enter the groove faster and more effectively, reducing the concentration difference between the plating solution in the groove and the outside, eliminating bubbles generated by hydrogen precipitation under metal overpotential, thereby increasing the metal deposition thickness in the hole and ensuring uniform electroplating at various locations on the wafer surface BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Other features, objects and advantages of the present invention will become more apparent from the detailed description of non-limiting embodiments made with reference to the following drawings:

[0032] Figure 1 It is a front view of the disc stirring device described in Example 1;

[0033] Figure 2 A side view of the disc stirring device described in Example 1;

[0034] Figure 3 A three-dimensional diagram of the disc stirring device described in Example 1;

[0035] Figure 4 for Figure 3 A partial enlarged view of

[0036] Figure 5 is a schematic structural diagram of the liquid inlet diversion device described in Example 2;

[0037] Figure 6 A schematic diagram of selecting four liquid inlet diversion devices;

[0038] Figure 7 It is the wafer thickness test point map;

[0039] Figure 8 This is a test result diagram of wafer electroplating non-uniformity in Test Example 1;

[0040] Fig. 9 This is a test result diagram of wafer electroplating non-uniformity in Test Example 2;

[0041] Fig.10 This is the test result of the thickness non-uniformity of a 12-inch wafer with a coating thickness of 0.92um in Test Example 3;

[0042] Fig.11 This is the test result of the thickness non-uniformity of a 12-inch wafer with a coating thickness of 0.91um in Test Example 3;

[0043] Fig.12 This is the test result of 45nm trench filling of Damascus wafer in Test Example 4;

[0044] Fig.13 The test results of the 63nm trench filling of Damascus wafer in Test Example 4 are shown in Figure 4. Figure 1 ;

[0045] Fig.14 The test results of the 63nm trench filling of Damascus wafer in Test Example 4 are shown in Figure 4. Figure 2 ;

[0046] Fig.15 This is the test result of 0.25um trench filling of Damascus wafer in Test Example 4;

[0047] Fig.16 This is the test result of 2um trench filling of Damascus wafer in Test Example 4;

[0048] The figure shows:

[0049] 100-disc stirring device;

[0050] 10- Chassis;

[0051] 20- stirring zone;

[0052] 21- upper surface of stirring zone;

[0053] 22- Side of stirring zone;

[0054] 30- skeleton structure;

[0055] 31- transverse skeleton;

[0056] 32-longitudinal skeleton;

[0057] 40-uniform flow port;

[0058] 41-Middle flow opening;

[0059] 42-edge flow uniformity port;

[0060] 60-Fin structure;

[0061] 70-nearly V-shaped opening;

[0062] 80- stirring plate;

[0063] 200-liquid inlet diversion device;

[0064] 210-liquid inlet;

[0065] 220-Diversion Department DETAILED DESCRIPTION

[0066] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and shown in the drawings here can be arranged and designed in various different configurations.

[0067] Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the present application for which protection is sought, but merely represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0068] It should be noted that similar numbers and letters represent similar items in the following figures. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in the subsequent figures. In addition, all directional indications in this application (such as up, down, left, right, front, back, bottom...) are only used to explain the relative position relationship, movement, etc. between the components under a certain specific posture (as shown in the figures). If the specific posture changes, the directional indication will also change accordingly. Furthermore, the descriptions involving "first", "second", etc. in the application are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated.

[0069] Example 1

[0070] like Figures 1 to 5 As shown, this embodiment provides a disc stirring device 100, such as Figure 2 As shown, it includes an inverted disc-shaped stirring plate 80, which includes an upwardly raised stirring zone 20 and a bottom plate 10 extending outward from the bottom of the stirring zone 20, and the stirring zone 20 includes a stirring zone upper surface 21 and a stirring zone side surface 22.

[0071] like Figure 1 and Figure 3 As shown, the stirring zone 20 includes a skeleton structure 30, and the area of ​​the skeleton structure 30 accounts for 35% to 45% of the area of ​​the stirring zone, preferably 40%. The skeleton structure 30 includes a plurality of transverse skeletons 31 and a plurality of longitudinal skeletons 32 (Note: transverse and longitudinal are used as directional indicators to describe the Figure 1 The relative position relationship of the skeletons in two directions intersecting at a specific viewing angle is based on the convenience of description. When the viewing angle changes, such as Figure 1 The normal view is switched to Figure 3 Even if the directional indication is changed accordingly, the lateral oblique viewing angle is still correspondingly referred to as the transverse skeleton 31 and the longitudinal skeleton 32).

[0072] The plurality of transverse frames 31 are arranged in parallel, and the plurality of longitudinal frames 32 are also arranged in parallel, and the transverse frames 31 and the longitudinal frames 32 are perpendicularly intersected. In this embodiment, the number of the longitudinal frames 32 is 4, and the number of the transverse frames 31 is relatively large.

[0073] like Figure 4 As shown, the transverse frame 31 is provided with a fin structure 60, and the stirring zone 20 further includes a uniform flow port 40, the uniform flow port 40 includes a middle uniform flow port 41 and a side uniform flow port 42, the middle uniform flow port 41 is opened in the area enclosed by the adjacent transverse frame 31 and the adjacent longitudinal frame 32, and the side uniform flow port 42 is as shown in FIG. Figure 4As shown, it is continuously opened on the edge of the upper surface 21 of the stirring zone, the side surface 22 of the stirring zone, and the surface of the bottom plate 10 near the position where it is connected to the bottom of the stirring zone.

[0074] In actual use, the disc stirring device 100 provided in this embodiment is installed in the plating chamber of the electroplating equipment. During electroplating, it will be in a rotating state. When the plating solution is circulated upward from the lower center position of the plating chamber, the plating solution will be broken up by the transverse skeleton 31 and the longitudinal skeleton 32 of the stirring zone 20 and pass through the uniform flow port 40, thereby making the plating solution more evenly distributed; at the same time, a fin structure 60 is provided on the transverse skeleton 31, which can drive the plating solution to move upward so that the plating solution reaches the surface of the wafer. At the same time, the gap formed between the fin structures 60 also enables the plating solution to be distributed at different positions of the skeleton, thereby accelerating the convection distribution between the effective chemical components of the plating solution on the wafer surface and eliminating the hydrogen bubbles generated by the overpotential as the stirring is carried out.

[0075] Furthermore, the edge flow-uniform port 42 is opened to the side surface 22 of the stirring zone and the chassis 10, so that the edge of the skeleton is openly distributed, thereby enabling the edge plating solution to flow out in a controlled manner, reducing the thickness of the wafer edge plating layer, and reducing the wafer plating edge effect. In general, the technical solution applies controlled physical stirring to the plating solution during the wafer plating process through the above-mentioned design, and performs appropriate diversion and uniform flow on the cathode inlet on the wafer surface. The plating solution moves uniformly with the stirring device, which will accelerate its diffusion into the grooves on the wafer surface, reduce the concentration difference of the plating solution at the center and edge of the wafer, and eliminate the bubbles generated by hydrogen precipitation under metal plating relative to the hydrogen overpotential, thereby accelerating the material exchange in the grooves, and promoting the deposition of copper ions, so as to achieve uniform thickness of the electroplated film at various locations on the entire wafer, and defect-free filling with higher filling efficiency in the grooves.

[0076] In particular, the disk stirring device provided in this embodiment can be used to solve the problems of uniformity of deposition of single damascene or dual damascene copper thin films on 12-inch wafers and defect-free filling of stepped steps of trench holes.

[0077] Example 2

[0078] This embodiment provides a disc stirring device 100, the structure of which is substantially the same as that of the stirring device provided in Embodiment 1, except that the present embodiment has the following improvements:

[0079] In this embodiment, the distance between adjacent transverse skeletons 31 is 1 to 5 mm, preferably 3 mm, and the distance between adjacent longitudinal skeletons 32 is between 40 and 80 mm, thereby further reducing the turbulence of the liquid surface of the plating solution, improving the flatness of the liquid surface, eliminating bubbles, and achieving uniform distribution of the components of the plating solution.

[0080] In addition, in this embodiment, the opening width of the middle flow outlet 41 and the edge flow outlet 42 is between 1 and 2 mm, preferably 1.5 mm. The opening width of the middle flow outlet 41 and the edge flow outlet 42 is uniform and consistent, thereby making the distribution of the plating solution more uniform, and this design also makes the edge of the skeleton 100% open distribution.

[0081] Furthermore, in the present embodiment, the fin structures 60 are trapezoidal in shape and have the same height, which is between 1 and 3 mm, preferably 2 mm, and the side inclination angles of the fin structures 60 are the same, and the intervals between adjacent fin structures 60 are the same, thereby forming a nearly V-shaped opening 70 with the same opening angle between adjacent fin structures 60. The design of the nearly V-shaped opening 70 allows the plating liquid to stay at different positions of the skeleton during the rotation of the stirring device, thereby accelerating the convection distribution between the effective chemical components of the plating liquid on the wafer surface and eliminating hydrogen bubbles generated by overpotential as the stirring is carried out.

[0082] In addition, the distribution of the nearly V-shaped openings 70 on the upper surface 21 of the stirring zone is not uniform. On the whole, the closer the upper surface 21 of the stirring zone is to its center, the greater the density of the nearly V-shaped openings 70, and the farther away from its center, the smaller the density of the nearly V-shaped openings 70, thereby reducing the difference in the amount of plating solution between the middle and edge of the wafer, thereby making the material distribution in the plating solution diffusion layer from the middle of the wafer to the edge of the wafer more uniform, reducing the concentration difference between the center of the wafer and the edge of the wafer.

[0083] In this embodiment, in order to obtain the technical effect of different distribution densities of the nearly V-shaped openings 70 as described above, the following technical solution can be adopted: the fin structures 60 at different positions have different lengths, that is, the closer to the center of the stirring zone, the smaller the length of the fin structure 60, and the farther away from the center of the stirring zone, the longer the length of the fin structure 60. When the spacing between adjacent fin structures 60 is the same, the density of the nearly V-shaped openings 70 formed by them is greater the closer to the center of the upper surface 21 of the stirring zone, and the density of the nearly V-shaped openings 70 farther away from the center is smaller.

[0084] The disc stirring device 100 provided in this embodiment accelerates the movement of each chemical component in the electroplating solution, promotes uniform ion density and accelerates diffusion, and eliminates bubbles; the design of the horizontal and vertical frames in the stirring device 100 is used to level the flatness of the cathode liquid surface of the electroplating chamber, effectively ensuring the consistency of concentration at various parts of the wafer surface; the nearly V-shaped opening 70 on the horizontal frame 31 has a high density at the stirring center and a low density at the edge, thereby reducing the difference in the amount of electroplating solution in the middle and edge of the wafer. Through the combination of the above designs, the concentration and liquid level of the electroplating solution at various positions on the wafer surface are effectively guaranteed, thereby improving the uniformity of the metal deposition thickness of the entire wafer.

[0085] Example 3

[0086] The present embodiment provides an electroplating tank, comprising an electroplating chamber, a driving device, and a disc stirring device 100 as described in Embodiment 1 or Embodiment 2. The disc stirring device 100 is horizontally arranged in the electroplating chamber, and is connected to the driving device. The driving device drives the disc stirring device 100 to rotate in the electroplating chamber, and the rotation speed is preferably 60 to 120 rpm (more preferably 100 rpm), and the rotation direction is preferably clockwise. The user can select the rotation speed of the disc stirring device 100 according to actual needs to improve the thickness distribution of the metal deposition layer on the wafer surface, eliminate bubbles, and improve groove filling.

[0087] A liquid inlet diversion device 200 is disposed at the bottom center of the electroplating chamber. The liquid inlet diversion device 200 may have one or more liquid inlet holes (such as four evenly arranged holes). Figure 5 As shown, the liquid inlet diverter device 200 includes a liquid inlet portion 210 at the bottom and a diverter portion 220 located on the liquid inlet portion 210. The liquid inlet portion 210 and the diverter portion 220 are cylindrical as a whole, and the lateral dimension of the diverter portion 220 is larger than that of the liquid inlet portion 210. The diverter portion 220 is evenly provided with multiple rows of diverter holes along its circumferential side. When the electroplating liquid enters the diverter portion 220 from the liquid inlet portion 210, the electroplating liquid will flow evenly into the electroplating chamber through the diverter holes provided on the diverter portion 220. The liquid inlet volume of the liquid inlet diverter device 200 is 25 to 35 liters / minute (preferably 27.5 to 35 liters / minute). The user can adjust the flow rate of the liquid inlet diverter device 200 through a circulating pump, so that the electroplating solution is fully circulated and the chemical composition is uniform, thereby accelerating the material exchange in the diffusion layer and improving the uniformity of the metal deposition thickness of the entire wafer.

[0088] This embodiment further reduces the turbulence of the electroplating liquid surface, improves the flatness of the liquid surface, eliminates bubbles, and achieves uniform distribution of the components of the electroplating liquid by adopting a specific stirring device with a vertical and horizontal skeleton layout, controlling the percentage of the open area and the stirring plate area, and improving the skeleton shape, combined with a rotating stirring method with speed control. At the same time, a liquid inlet diversion device is used to make the electroplating liquid flow evenly to the cavity, and different positions of the electroplating cavity are evenly filled with the electroplating liquid, and then the chemical components in the electroplating liquid are evenly distributed on the wafer surface, reducing the concentration difference of the chemical components inside the electroplating cavity, thereby improving the uniformity of the metal deposition thickness of the entire wafer.

[0089] The applicant has found through experiments that for Damascus wafers, the groove size is 45nm-2um, by controlling the rotation speed of the disc stirring device 100 to 80-100 rpm, the stirring direction is clockwise stirring, and the liquid inlet device is selected from the liquid inlet diversion device 200 mentioned in this embodiment (such as Figure 6As shown, a four-hole liquid inlet method is adopted, and the liquid inlet flow rate is controlled to be 30-35 liters / minute, which can achieve a wafer thickness unevenness of <5% and a defect-free electroplating filling effect in the groove.

[0090] The following is a description of the technical effects achieved by the present invention through the above structural design and the selection of parameters such as flow rate and stirring device speed through some test examples:

[0091] Test Example 1:

[0092] For Damascus 12-inch wafers, electroplating is completed when the rotation speed of the disk stirring device is controlled to be 60-120 rpm, the stirring direction is clockwise, and the cathode liquid flow rate is 30 L / min. Figure 7 The 61 points shown are used as thickness test points to test the uniformity of wafer electroplating. The test results are as follows: Figure 8 As shown, the wafer thickness non-uniformity is calculated and the results are as follows:

[0093] Stirring speed 60rpm 80rpm 100rpm 120rpm Wafer thickness non-uniformity 8.32％ 5.03％ 4.01％ 7.18％

[0094] From the above results, it can be seen that when the stirring speed is 100rpm, the uniformity of wafer thickness is best, and the non-uniformity is <5%.

[0095] Test Example 2:

[0096] For Damascus 12-inch wafers, electroplating was completed when the rotation speed of the disk stirring device was controlled to be 100 rpm and the stirring direction was clockwise, and the cathode liquid flow rate was 25-35 rpm. Figure 7 The 61 points shown are used as thickness test points to test the uniformity of wafer electroplating. The test results are as follows: Fig. 9 As shown, the wafer non-uniformity is calculated and the results are as follows:

[0097] Cathode solution flow 25LPM 27.5LPM 30LPM 32.5LPM 35LPM Wafer thickness non-uniformity 28.86％ 5.37％ 3.81％ 3.49％ 4.91％

[0098] From the above results, it can be seen that when the cathode solution flow rate is between 27.5 and 35 rpm, the uniformity of wafer thickness is best, and the non-uniformity is <5%.

[0099] When the cathode flow rate is too low (such as 25 LPM), the amount of solution circulating to the cathode surface is not enough to fill the entire cavity, resulting in less contact between the solution and the wafer in some places.

[0100] Test Example 3:

[0101] For Damascus 12-inch wafers, electroplating is completed while controlling the rotation speed of the disc stirring device to 80-100 rpm and the stirring direction to be clockwise, and the cathode solution flow rate to be 30-35 liters / minute.

[0102] Still Figure 7 The 61 points shown are used as thickness test points to test the wafer electroplating uniformity. It is found that the wafer thickness non-uniformity can reach a level of <5% and the best level is 1.8%.

[0103] Regarding the monitoring results of wafer non-uniformity, the coating thickness is 0.92um, and the best non-uniformity of 12-inch wafer is 1.8%. Fig.10 As shown; the coating thickness is 0.91um, and the test results of 12-inch wafer non-uniformity is 3.2% as shown Fig.11 shown.

[0104] Test Example 4:

[0105] Filling of Damascus with different groove sizes, Fig.12 The test results of 45nm trench filling on Damascus wafer are shown. Fig.13 and Fig.14 The test results of 63nm trench filling on Damascus wafer are shown. Fig.15 The test results of 0.25um trench filling on Damascus wafer are shown. Fig.16 Shows the test results of 2um trench filling on Damascus wafer.

[0106] From the above test results, it can be seen that by adopting specific stirring devices and liquid inlet devices to improve its process conditions, Damascus can achieve defect-free filling of M1 (a graphic wafer structure) 45nm to 2um process grooves.

[0107] Conclusion: By using a specific stirring device and liquid inlet device to improve the process conditions, the non-uniformity of Damascus wafers can reach <5%, and the groove filling can achieve defect-free filling of the M1 (a graphic wafer structure) 45nm to 2um process groove.

[0108] The above describes the specific embodiments of the present invention. Based on the above description, relevant personnel can make various changes and modifications without departing from the technical concept of the present invention.

Claims

1. A disc stirring device, characterized in that: The stirring plate comprises an inverted disc-shaped stirring plate, wherein the stirring plate comprises a stirring zone protruding upward and a bottom plate extending outward from the bottom of the stirring zone, wherein the stirring zone comprises an upper surface of the stirring zone and a side surface of the stirring zone; The stirring zone includes a skeleton structure, the area of ​​the skeleton structure accounts for 35% to 45% of the area of ​​the stirring zone, the skeleton structure includes a plurality of intersecting transverse skeletons and longitudinal skeletons, and a fin structure is arranged on the transverse skeleton; The stirring zone also includes a uniform flow port, which includes a middle uniform flow port and an edge uniform flow port. The middle uniform flow port is opened in the area enclosed by adjacent transverse frames and adjacent longitudinal frames, and the edge uniform flow ports are continuously opened on the edge of the upper surface of the stirring zone, the side of the stirring zone, and the position of the bottom plate surface close to its connection with the bottom of the stirring zone.

2. The disc stirring device according to claim 1, characterized in that: The fin-type structure is in a trapezoidal shape, with a height between 1 and 3 mm, and a nearly V-shaped opening is formed between adjacent fin-type structures.

3. The disc stirring device according to claim 2, characterized in that: The density of the nearly V-shaped openings is greater the closer to the center of the upper surface of the stirring zone, and is lower the farther away from the center of the upper surface of the stirring zone.

4. The disc stirring device according to claim 1, characterized in that: The distance between adjacent transverse frames is between 1 and 5 mm, and the distance between adjacent longitudinal frames is between 40 and 80 mm.

5. The disc stirring device according to claim 1, characterized in that: The opening widths of the middle flow-uniform opening and the side flow-uniform opening are between 1 and 2 mm, and the opening widths of the middle flow-uniform opening and the side flow-uniform opening are uniform and consistent.

6. An electroplating tank, characterized in that: It comprises an electroplating chamber and the disc stirring device according to any one of claims 1 to 5, wherein the disc stirring device is horizontally arranged in the electroplating chamber.

7. The electroplating tank according to claim 6, characterized in that: The device also comprises a driving device, which is connected to the disk stirring device and can drive the disk stirring device to rotate at a preset speed.

8. The electroplating tank according to claim 7, characterized in that: The preset speed is between 60 and 120 revolutions per minute, and the rotation direction is clockwise.

9. The electroplating tank according to claim 6, characterized in that: A liquid inlet diversion device is arranged at the bottom center of the electroplating chamber, and the liquid inlet diversion device comprises a liquid inlet portion and a diversion portion located above the liquid inlet portion, and a plurality of rows of diversion holes are evenly arranged on the diversion portion along its extension direction.

10. The electroplating tank according to claim 9, characterized in that: The liquid inlet flow rate of the liquid inlet diversion device is 25 to 35 liters per minute.

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