Agitating mechanism of electroplating apparatus, electroplating apparatus, and electroplating method

Abstract

An agitating mechanism of an electroplating apparatus, an electroplating apparatus, and an electroplating method, relating to the technical field of semiconductor manufacturing. The agitating mechanism comprises a blocking area (201) and an agitating area (202); the blocking area (201) is used for weakening a flow field of said area; the agitating area (202) comprises a plurality of first blades (203) arranged in parallel; during the electroplating of a wafer, when a wafer notch (301) is located in the blocking area (201), the rotating speed of the wafer is a first rotating speed, and when the wafer notch (301) is located in the agitating area (202), the rotating speed of the wafer is a second rotating speed, wherein the first rotating speed is less than the second rotating speed; the blocking area (201) is used for reducing the total amount of metal ions received in the blocking area (201) by the wafer notch (301). The blocking area (201) is provided on the agitating mechanism, and the rotating speed of the wafer is controlled to reduce in due time, so that the total amount of metal ions received in the blocking area (201) by the wafer notch (301) is reduced, avoiding the occurrence of excessive electroplating height in the peripheral area of the wafer notch in an electroplating technological process.

Description

Stirring mechanism of electroplating equipment, electroplating equipment and electroplating method Technical Field

[0001] The present invention relates to the technical field of semiconductor manufacturing, and in particular to a stirring mechanism of electroplating equipment, electroplating equipment and an electroplating method. Background Art

[0002] With the increasing popularity of wafer-level packaging (WLP) processes, there is a demand for electroplating on wafers containing non-plated areas. A typical non-plated area is the wafer notch. In some applications, the die on a wafer may be arranged asymmetrically, resulting in irregularly shaped non-plated areas. For example, the wafer notch, a relatively common non-plated area, is used as an example. In the plating area where the chips are located, there are many openings in the photoresist, where metal is deposited. During electroplating, these metal-deposited openings act as conductive wires. Since no chips are located in the wafer notch, which serves as the non-plated area, there are no openings in the photoresist and no metal is deposited. For both the plating and non-plated areas, when subjected to a uniform electric field, the non-plated area lacks conductive wires and therefore cannot generate current. This results in a higher current flowing in the conductive wires in the surrounding area. This effectively results in areas surrounding the non-plated area being exposed to a higher metal ion density, resulting in a higher plating rate and, ultimately, a higher plating height than other areas. For the wafer-level packaging process, the overall height control is very strict. A higher electroplating height near the wafer notch can easily lead to reduced product yield and production loss.

[0003] Summary of the Invention

[0004] The purpose of the present invention is to provide a stirring mechanism of electroplating equipment, electroplating equipment and electroplating method to improve the uniformity of electroplating height.

[0005] In the first aspect, the present invention proposes a stirring mechanism of an electroplating device, wherein the stirring mechanism includes a shielding area and a stirring area, wherein the shielding area is used to weaken the flow field in the area; the stirring area includes a plurality of first blades arranged in parallel; wherein, during the wafer electroplating process, when the wafer notch is located in the shielding area, the rotation speed of the wafer is a first rotation speed, and when the wafer notch is located in the stirring area, the rotation speed of the wafer is a second rotation speed, and the first rotation speed is less than the second rotation speed; the shielding area is used to reduce the wafer rotation speed, so that the total amount of metal ions received by the wafer notch in the shielding area is reduced.

[0006] According to a specific implementation of the embodiment of the present application: the shielding area includes an area formed by a plurality of straight edges connected in sequence and an edge line of the stirring mechanism.

[0007] According to a specific implementation of the embodiment of the present application: the shielding area includes an area enclosed by the curved edge and the edge line of the stirring mechanism.

[0008] According to a specific implementation of the embodiment of the present application: the shielding area is a closed block structure, and the height of the upper end surface of the shielding area is higher than the height of the upper end surface of the first blade.

[0009] According to a specific implementation of the embodiment of the present application: a stirring unit is provided in the shielding area, and the stirring force of the stirring unit is weaker than the stirring force of the first blade.

[0010] According to a specific implementation of an embodiment of the present application: the stirring unit includes a plurality of second blades arranged in parallel, and the stirring force of the second blades located in the shielding area is weaker than the stirring force of the first blades in the stirring area.

[0011] According to a specific implementation of the embodiment of the present application: the width of the upper end surface of the second blade in the shielding area is greater than the width of the lower end surface of the second blade. According to a specific implementation of the embodiment of the present application:

[0012] The height of the upper end surface of the second blade in the shielding area is higher than or equal to the height of the upper end surface of the first blade in the stirring area.

[0013] According to a specific implementation method of the embodiment of the present application: the shielding area is a hollow frame structure.

[0014] According to a specific implementation of the embodiment of the present application: the upper end surface of the frame of the shielding area is higher than the upper end surface of the stirring area.

[0015] In a second aspect, the present application proposes an electroplating device for electroplating on a wafer surface, the electroplating device including the aforementioned stirring mechanism, and the electroplating device is configured to: during the electroplating process, control the stirring mechanism to move parallel to the wafer to stir the plating solution.

[0016] According to a specific implementation method of an embodiment of the present application: the electroplating equipment also includes a rotatable wafer holding device, the wafer holding device can rotate, the wafer holding device has a clamp, the clamp is used to fix the wafer on the wafer holding device and rotate with the clamp, and the relative position of the wafer notch and the clamp is fixed.

[0017] In a third aspect, the present application proposes an electroplating method, comprising: providing a stirring mechanism including a shielding area and a stirring area in the electroplating equipment, wherein the shielding area is used to weaken the flow field in the area, and the stirring area includes a plurality of parallel first blades; the electroplating equipment provided with the stirring mechanism is used to perform electroplating on the surface of the wafer, and the stirring mechanism is controlled to move parallel to the wafer to stir the plating solution; the shielding area is used to weaken the flow field in the area; the stirring area is composed of a plurality of parallel blades; when the wafer notch is located in the shielding area, the rotation speed of the wafer is a first rotation speed, and when the wafer notch is located in the stirring area, the rotation speed of the wafer is a second rotation speed, and the first rotation speed is less than the second rotation speed; the shielding area is used to reduce the total amount of metal ions received by the wafer notch in the shielding area. When the wafer notch is located in the shielding area, the wafer rotation speed is reduced so that the total amount of metal ions received by the wafer notch in the shielding area is reduced. According to a specific implementation method of an embodiment of the present application: a rotatable wafer holding device is provided in the electroplating equipment, and the rotation speed of the wafer is controlled by adjusting the rotation speed of the wafer holding device.

[0018] The stirring mechanism, electroplating equipment and electroplating method of the electroplating equipment of the present invention reduce the flow rate of the plating solution in the shielding area by setting a shielding area on the stirring mechanism. At the same time, in combination with the process, the rotation speed of the wafer is timely controlled to be reduced, so that the time the wafer gap is located in the shielding area is prolonged, so that the total amount of metal ions received by the wafer gap in the shielding area is reduced, and the occurrence of the phenomenon of excessive electroplating height in the area surrounding the wafer gap during the electroplating process is avoided. Other features and advantages of the present invention will be explained in the subsequent description, and part of them will become obvious from the description, or can be understood by practicing the present invention. The objects and other advantages of the present invention can be achieved and obtained through the structures indicated in the description and the drawings.

[0019] Summary of the Figures

[0020] The features and properties of the present invention are further described by the following examples and accompanying drawings.

[0021] FIG1 shows a schematic structural diagram of an electroplating device according to an embodiment of the present invention;

[0022] FIG2 shows another schematic structural diagram of the electroplating equipment according to an embodiment of the present invention;

[0023] FIG3 is a schematic diagram showing the structure of the area formed by a straight edge of the shielding area of ​​the stirring mechanism and the edge line of the stirring mechanism in Example 1 of the present invention;

[0024] FIG4 is a schematic diagram showing the structure of the area formed by the two straight sides of the shielding area of ​​the stirring mechanism and the edge line of the stirring mechanism in Example 1 of the present invention;

[0025] FIG5 is a schematic diagram showing the structure of the area formed by the three straight sides of the shielding area of ​​the stirring mechanism and the edge line of the stirring mechanism in Example 1 of the present invention;

[0026] FIG6 is a schematic diagram showing the structure of the area formed by the curved edge of the shielding area of ​​the stirring mechanism and the edge line of the stirring mechanism in Example 1 of the present invention;

[0027] FIG7 shows a perspective schematic diagram of a stirring mechanism in Example 2 of the present invention;

[0028] FIG8 shows a perspective schematic diagram of a stirring mechanism in Example 3 of the present invention;

[0029] FIG9 shows a schematic structural diagram of a stirring mechanism in the prior art;

[0030] FIG10 is a schematic diagram showing electron density detection results on different regions of a wafer corresponding to a stirring mechanism of the prior art and a stirring mechanism of the present invention;

[0031] FIG11a shows a schematic diagram of the position of the detection area a corresponding to the stirring mechanism in the prior art;

[0032] FIG11 b shows a graph showing the flow rate variation of the electroplating solution in the X and Z directions of a region a during the electroplating process using a prior art stirring mechanism;

[0033] FIG11c is a schematic diagram showing the change of the electric field intensity in area a of the prior art stirring mechanism during the electroplating process;

[0034] FIG12a is a schematic diagram showing the position of the detection area b corresponding to the shielding area of ​​the stirring mechanism in FIG4 ;

[0035] FIG12 b shows a graph showing the flow rate variation of the electroplating solution in the X and Z directions of the stirring mechanism in FIG4 during the electroplating process; and

[0036] FIG12 c is a schematic diagram showing the change in electric field intensity in region b of the stirring mechanism in FIG4 during the electroplating process.

[0037] Preferred embodiments of the present invention

[0038] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0039] After actual observation and summary of the electroplating process and results, the inventors found that in order to adapt to the situation where different areas of the wafer need to correspond to different fluidities of the electroplating solution in the same electroplating chamber, the present invention proposes a structural design of the stirring mechanism of the electroplating equipment to achieve the different requirements of accurately controlling the total amount of metal ions in the electroplating solution that different areas of the wafer need to receive, and at the same time combine the rotation speed of the wafer for control to achieve better control effect.

[0040] Please refer to Figures 1 and 2, which respectively show schematic structural diagrams of the electroplating equipment of an embodiment of the present invention at different angles. The electroplating equipment of an embodiment of the present invention includes an electroplating chamber 100 and a stirring mechanism 200, and the stirring mechanism 200 is arranged in the electroplating chamber 100. The electroplating chamber 100 is used to accommodate the electroplating solution. During the process, the wafer 300 is located directly above the stirring mechanism 200, and the stirring mechanism 200 moves parallel to the wafer 300 to stir the electroplating solution. In an embodiment of the present invention, the material of the stirring mechanism 200 is an insulator, such as plastic materials such as PVC, PC, CPVC, PPS, PEEK, and PTFE. The stirring mechanism 200 includes a shielding area 201 and a stirring area 202. The shielding area 201 is used to shield the flow field, weaken the stirring force of the plating solution in the area, reduce the fluidity of the plating solution in the area, and reduce the metal ion density of the plating solution in the area corresponding to the shielding area 201. The stirring area 202 is composed of a plurality of parallel first blades 203, and the gaps between adjacent first blades 203 allow liquid and electric fields to pass through. During the wafer electroplating process, when the wafer notch 301 is located in the shielding area 201, the rotational speed of the wafer 300 is a first rotational speed. When the wafer notch 301 is located in the stirring area 202, the rotational speed of the wafer 300 is a second rotational speed, and the first rotational speed is less than the second rotational speed. The shielding area 201 is used to reduce the total amount of metal ions received by the wafer notch 301 in the shielding area 201. The first rotational speed is lower than the second rotational speed, which can ensure that in a complete electroplating process, the time that the wafer notch 301 is in the shielding area 201 is prolonged, and the ion exchange rate around the wafer notch 301 will be reduced, thereby avoiding the electroplating height near the wafer notch 301 being too high, thereby achieving the purpose of uniform electroplating.

[0041] Furthermore, when designing the shielding area 201, the area of ​​the shielding area 201 is larger than the area of ​​the wafer notch 301 to ensure that the wafer notch 301 can be completely within the shielding area 201, so that the shielding effect is better. Specifically, when actually setting the stirring mechanism 200, the size and shape of the stirring mechanism 200 will be matched according to the size and shape of the wafer 300, so that the plating liquid and the electric field in the stirring area 202 can better pass through the gap between adjacent first blades 203; the shielding area 201 is designed according to the position and size of the wafer notch 301, so that the area of ​​the shielding area 201 is larger than the area of ​​the wafer notch 301 to ensure that the wafer notch 301 can be completely within the shielding area 201. For example, as shown in Figure 2, when the wafer notch 301 is set at the edge of the wafer 300, the shielding area 201 is correspondingly set at the edge of the stirring mechanism 200, and the area of ​​the shielding area 201 is larger than the area of ​​the wafer notch 301.

[0042] Referring to Figure 1, the electroplating equipment of an embodiment of the present invention also includes a wafer holding device 400, and the wafer 300 is fixed by the wafer holding device 400. The wafer holding device 400 can rotate, and the wafer 300 is fixed on the wafer holding device 400 and rotates with the wafer holding device 400. The relative position of the wafer notch 301 on the wafer 300 and the wafer holding device 400 is fixed, so the position of the wafer notch 301 can be determined based on the rotation position of the wafer holding device 400. During the electroplating process, the wafer holding device 400 drives the wafer 300 to rotate. The rotation speed can be from 0.1rpm to 500rpm, and can be specifically determined according to actual conditions. The position of the wafer notch 301 is tracked according to the rotational speed of the wafer holding device 400. When the wafer notch 301 is in the stirring area 202, the rotational speed of the wafer 300 is controlled to be the second rotational speed. When the wafer notch 301 begins to enter the shielding area 201, the rotational speed of the wafer 300 is reduced so that the wafer 300 rotates at the first rotational speed. The reduction in the rotational speed of the wafer 300 reduces the total amount of metal ions received by the wafer notch 301 in the shielding area 201, thereby avoiding the generation of a higher metal ion density in the area surrounding the wafer notch 301, which leads to the occurrence of excessive electroplating height in the area surrounding the wafer notch 301.

[0043] In order to achieve the above objectives, the embodiment of the present invention performs a series of optimizations on the specific structure of the stirring mechanism 200, which will be described in detail below.

[0044] Example 1

[0045] In this embodiment, the shielding area 201 is a closed block structure. Specifically, the shielding area 201 may include an area formed by several straight edges connected in sequence and the edge line of the stirring mechanism. The meaning of "several" in the embodiment of the present invention is an integer greater than or equal to 1; the shielding area 201 can also be an area formed by a curved edge and the edge line of the stirring mechanism.

[0046] Exemplarily, please refer to Figure 3, which illustrates the shielding area 201 as an area formed by several straight edges connected in sequence and the edge line of the stirring mechanism, and the shielding area 201 is formed when the number of straight edges is 1. As can be seen from Figure 3, the two ends of the straight edge 3011 are directly connected to the edge line 3012 of the stirring mechanism to form a closed enclosed area, namely the shielding area 201. In this embodiment, the shielding area 201 is a closed block structure; please refer to Figure 4, which illustrates the shielding area 201 formed when the number of straight edges is 2. As can be seen from Figure 4, two straight edges 4011a and 4011b are connected in sequence, and then the free end of the straight edge 4011a is connected to the edge line 4012 of the stirring mechanism, and the free end of the straight edge 4011b is connected to the edge line 4012 of the stirring mechanism. The closed area enclosed by the two straight edges 4011a and 4011b and the edge line 4012 of the stirring mechanism is the shielding area 201, and this area is a closed block structure. The free end refers to the end with straight edges 4011a and 4011b located on the outside, respectively. It should be understood that although described as lines or edges, the stirring mechanism and the shielding area 2011 are both structures with a certain thickness. Therefore, the edge line of the stirring mechanism indicates that the cross section of the stirring mechanism is a vertical curved surface or plane of the edge line, and the straight edge indicates that the vertical plane of the shielding area has a straight cross section.

[0047] Please refer to Figure 5, which illustrates the shielding area 201 formed when the number of straight edges is 3; as can be seen from Figure 5, one end of the straight edge 5011a is connected to the edge line 5012 of the stirring mechanism, the other end of the straight edge 5011a is connected to one end of the straight edge 5011b, the other end of 5011b is connected to one end of the straight edge 5011c, and the other end of 5011c is connected to the edge line 5012 of the stirring mechanism. The straight edges 5011a, 5011b, 5011c and the edge line 5012 of the stirring mechanism together form a closed area, which is the shielding area 201, and the area contains a closed block structure.

[0048] In other embodiments, the shielding area 201 is an area enclosed by a curved edge and an edge line of the stirring mechanism.

[0049] Please refer to Figure 6, which illustrates the shielding area 201 formed by the curved edge 6011 and the stirring mechanism edge line 6012. As can be seen from Figure 6, the two ends of the straight edge 6011 directly connect with the stirring mechanism edge line 6012, forming a closed enclosed area, namely the shielding area 201. In this embodiment, the shielding area 201 is a closed block structure. It should be understood that the above is only an example, and the number of straight edges is not limited in the embodiments of the present invention. When the number of straight edges is greater than or equal to 2, the angle formed by two connected straight edges is not limited in the embodiments of the present invention. There is no specific limitation on the specific shape of the curved edge, and the curved edge can be an arc or a corrugated curve.

[0050] Furthermore, the height of the upper end surface of the shielding area 201 is higher than the height of the upper end surface of the first paddle 203 in the stirring area 202, that is, during the process, the upper end surface of the shielding area 201 is closer to the wafer 300 than the upper end surface of the first paddle 203. The distance between the shielding area 201 and the wafer 300 is smaller than the distance between the first paddle 203 and the wafer 300. In the process of stirring the electroplating solution by the stirring mechanism 200, the space between the shielding area 201 and the wafer 300 is smaller, and less electroplating solution can be accommodated. At the same time, because the fluidity of the electroplating solution in the corresponding area of ​​the shielding area 201 is less than the fluidity of the electroplating solution in the corresponding area of ​​the stirring area 202, the metal ion exchange rate in the electroplating solution will be lower than that in the stirring area 202. When the wafer notch 301 rotates into this area, the wafer 300 is controlled to slow down so that the wafer notch 301 is located in the region. The time of shielding area 201 is prolonged, the total amount of metal ions received by the area around the wafer notch 301 is reduced, and the electroplating height around the wafer notch 301 is reduced, so that the electroplating height of the wafer 300 as a whole remains uniform; at the same time, the shielding area 201 is a closed block structure made of insulating material, which will prevent the electric field below the shielding area 201 from being transmitted to the top of the shielding area 201 to act on the wafer 300. Therefore, the current density in the shielding area 201 is also small. During electroplating, the coating on the area corresponding to the shielding area 201 on the wafer 300 is also reduced accordingly. When the wafer notch 301 is in the shielding area 201 for a long time, the electroplating height around the wafer notch 301 is suppressed more significantly than the non-notch area, thereby ensuring that the electroplating height of the wafer 300 as a whole remains uniform. It should be understood that in other embodiments, the relative height of the upper end face of the shielding area 201 and the upper end face of the first blade 203 in the stirring area 202 can be set according to actual needs.

[0051] During the electroplating process, when the wafer notch 301 is located in the shielding area 201, the shielding area 201 has a shielding effect on the electric field, and the current density in the shielding area 201 is relatively low. At this time, the rotation speed of the wafer 300 is reduced, so that the time the wafer notch 301 is in the shielding area 201 becomes longer. Relatively speaking, the coating on the area corresponding to the wafer 300 shielded by the shielding area 201 will be reduced, so that the electroplating height of the area around the wafer notch 301 can be controlled. Because the block structure has a closed characteristic, when the electric field in the electroplating chamber 100 passes through the shielding area 201 of the closed block structure, it will be blocked. In particular, when the stirring mechanism in the embodiment of the present invention adopts an insulating material, the electric field cannot pass through the shielding area 201, so that the total amount of electricity received by the area around the wafer notch 301 in the shielding area 201 is reduced, thereby forming an effect of suppressing the electroplating height of the area around the wafer notch 301. At the same time, when the shielding area 201 is a closed block structure, its effect of stirring the plating liquid is weak, so that the fluidity of the plating liquid in the shielding area 201 is weaker than the fluidity of the plating liquid in the stirring area 202, thereby reducing the total amount of metal ions received by the wafer notch 301 in the shielding area 201, and further suppressing the plating height in the area surrounding the wafer notch 301.

[0052] Example 2

[0053] The structure of the stirring mechanism of Example 2 is slightly different from that of Example 1. A stirring unit is provided in the shielding area, and the stirring force of the stirring unit is weaker than the stirring force of the blades in the stirring area. Exemplarily, the structure of the stirring unit can be a plurality of parallel blades, and the blades in the shielding area can be perpendicular to the blades in the stirring area, or can be parallel to the blades in the stirring area, as shown in Figure 7. This embodiment is illustrated by taking the stirring unit as a plurality of parallel blades and the second blade 204 in the shielding area 201 being parallel to the first blade 203 in the stirring area 202 as an example. In order to make the stirring force of the second blade 204 weaker than the stirring force of the first blade 203, it can be designed from many factors, including but not limited to: the cross-sectional shape of the second blade 204, the gap between adjacent second blades 204, etc. Furthermore, the width of the upper end face of the second blade 204 is greater than the width of the lower end face of the second blade 204, so as to achieve the purpose of weakening the flow field while shielding the electric field. Exemplarily, the cross-sectional shape of the second blade 204 includes, but is not limited to, an inverted trapezoid, an inverted "T" shape, or an inverted triangle, etc. The spacing between adjacent second blades 204 can be selected to be smaller than the distance between adjacent first blades 203, or can be selected to be greater than or equal to the distance between adjacent first blades 203. In this embodiment, no specific limitation is made on the various factors affecting the stirring force of the stirring unit. As long as the stirring force of the second blade 204 located in the shielding area 201 is weaker than the stirring force of the first blade 203 in the stirring area 202, the solution falls within the scope of protection of the present invention. In the actual processing and manufacturing process, the first blade 203 and the second blade 204 can be manufactured by the same blade in a segmented design and integrated molding manner, or they can be manufactured in segments and then installed and fixed.

[0054] Furthermore, the height of the upper end surface of the second blade 204 is higher than or equal to the height of the upper end surface of the first blade 203 .

[0055] In some embodiments, when the upper end surface of the second blade 204 and the upper end surface of the first blade 203 are located on the same horizontal plane, the stirring force achieved by the cross-sectional shape of the second blade 204, the gap between adjacent second blades 204, or the combination of the two can be adjusted and designed to achieve the purpose of making the stirring force of the second blade 204 weaker than the stirring force of the first blade 203.

[0056] In other embodiments, the upper end surface of the second blade 204 is higher than the upper end surface of the first blade 203, that is, during the process, the upper end surface of the second blade 204 is closer to the wafer 300 than the upper end surface of the first blade 203. The distance between the second blade 204 and the wafer 300 is smaller than the distance between the first blade 203 and the wafer 300, so that when the stirring mechanism 200 stirs the plating solution, the fluidity of the plating solution in the shielding area 201 is lower than the fluidity of the plating solution in the stirring area 202, thereby achieving the purpose of lowering the metal ion exchange rate in the plating solution in the shielding area 201 than the metal ion exchange rate in the plating solution in the stirring area 202. When the wafer notch 301 rotates into the shielding area 201, the wafer 300 is controlled to decelerate to the first speed, so that the time that the wafer notch 301 is in the shielding area 201 is prolonged, the metal ion mass transfer rate is reduced, and the electroplating height of the area surrounding the wafer notch 301 is reduced, so that the overall electroplating height of the wafer 300 remains uniform. It should be understood that when the upper end surface of the second blade 204 is higher than the upper end surface of the first blade 203, factors such as the cross-sectional shape of the second blade 204 and the first blade 203, the gap between adjacent blades, or a combination of the two can also be considered to adjust the stirring force of the shielding area 201 and the stirring area 202, so as to better achieve the purpose of making the stirring force of the second blade 204 weaker than the stirring force of the first blade 203.

[0057] The height of the upper end surface of the second blade 204 can be set according to actual needs.

[0058] Example 3

[0059] The structure of the stirring mechanism in Example 3 is slightly different from that in Example 1. The blocking area 201 in Example 1 is a solid structure. The shielding area 201 is a hollow frame structure. No structure is provided within the shielding area 201 of the hollow frame design. In this embodiment, the shielding area 201 is formed solely by the edge of the stirring mechanism and a curved edge or several consecutively connected straight edges. The shape of the shielding area 201 thus formed is similar to that shown in Figures 3-6 of Example 1 and will not be further described here. Since no paddle-like structure is provided in the shielding area 201, the stirring force inside the shielding area 201 is weaker than the stirring force in the stirring area 202, and the fluidity of the plating solution in the shielding area 201 is also weaker than the fluidity of the plating solution in the stirring area 202, thereby causing the mass transfer rate of metal ions in the plating solution to be lower than that in the stirring area 202. Combined with the control method for decelerating the wafer 300 when the wafer notch 301 rotates into the shielding area 201, the time that the wafer notch 301 is in the shielding area 201 is prolonged, the mass transfer rate of metal ions is reduced, and the electroplating height in the area surrounding the wafer notch 301 is reduced, so that the overall electroplating height of the wafer 300 remains uniform.

[0060] 8 , the upper end surface of the edge frame of the shielding region 201 is higher than the upper end surface of the paddle in the stirring region 202 to prevent rapid exchange of the plating solution in the stirring region 202 with the plating solution in the shielding region 201. It should be understood that the height of the upper end surface of the edge frame of the shielding region 201 can also be selected to be equal to the height of the upper end surface of the paddle in the stirring region 202.

[0061] When setting the specific location and shape of the shielding area 201, please refer to Example 1, which will not be described in detail here.

[0062] The present application also provides an electroplating method using an electroplating device, comprising:

[0063] Step S1: setting a stirring mechanism including a shielding area and a stirring area in the electroplating equipment, wherein the shielding area is used to weaken the flow field in the area, and the stirring area includes a plurality of first blades arranged in parallel;

[0064] Step S2: electroplating is performed on the surface of the wafer using electroplating equipment, and the stirring mechanism is controlled to move parallel to the wafer to stir the electroplating solution; wherein, when the wafer notch is located in the shielding area, the rotation speed of the wafer is a first rotation speed, and when the wafer notch is located in the stirring area, the rotation speed of the wafer is a second rotation speed, and the first rotation speed is less than the second rotation speed; the shielding area is used to reduce the total amount of metal ions received by the wafer notch in the shielding area.

[0065] The setting of the wafer rotation speed in the above steps can be controlled by a controller in the electroplating equipment.

[0066] Furthermore, a rotatable wafer holding device is provided in the electroplating equipment, and the rotation speed of the wafer is controlled by regulating the rotation speed of the wafer holding device. Specifically, the rotation speed of the wafer holding device can be regulated by a controller of the electroplating equipment.

[0067] In order to demonstrate the effects achieved by the present invention, the shielding area 201 of the stirring mechanism 200 is taken as an example for explanation, referring to FIG9 and FIG4 . FIG9 shows a schematic structural diagram of a stirring mechanism in the prior art.

[0068] Under the same electroplating process conditions, the stirring mechanisms of Figures 9 and 4 were placed in the electroplating chamber respectively, and the charge density in the electroplating solution below the wafer was detected respectively. For specific results, please refer to Figure 10, which shows a schematic diagram of the charge density detection results of the stirring mechanism of the prior art and the stirring mechanism of the present invention corresponding to different areas of the wafer. In Figure 10, the horizontal axis is the coordinate extending from one edge of the wafer 300 along the diameter direction to the other side. It can be seen that the size of the wafer 300 in this embodiment is 300mm; the vertical axis of Figure 10 is the charge density value of the lower surface of the wafer 300; line a is the measurement result of the charge density at different positions of the wafer during the electroplating process using the stirring mechanism of the prior art; line b is the measurement result of the charge density at different positions of the wafer during the electroplating process using the stirring mechanism of the present invention. As shown in Figure 10, when extending from one edge of the wafer 300 to the other side along the diameter direction, line a and line b have an intersection. The area between the first intersection A and the second intersection B is the shielding area 201 corresponding to the wafer notch 301. The charge density of line b in the shielding area 201 is significantly smaller than the charge density of line a, which indicates that after the shielding area 201 is set, the stirring mechanism 200 can significantly reduce the charge density in the shielding area 201. During the electroplating process, when the wafer notch 301 enters the shielding area 201, the total amount of electricity received will be reduced, thereby reducing the electroplating height of the area surrounding the wafer notch 301.

[0069] The plating solution flow rate within the same area of ​​the stirring mechanism 200 with a shielded area and the stirring mechanism 600 without a shielded area were further tested. Specifically, when the wafer 300 was placed in the wafer holding device 400, an area with the same area as the shielded area 201 was defined as the testing area, centered on the central axis of the wafer notch 301. The testing area corresponding to the stirring mechanism of the prior art is shown in FIG11a , where area a is the testing area; the testing area corresponding to the stirring mechanism of the present invention is shown in FIG12a , where area b is the testing area. The flow velocities in the X and Z directions in regions a and b were tested. The flow velocity results in the X direction in region a are shown in FIG11b . The abscissa in FIG11b represents the position coordinates extending from the X endpoint located on the edge of the wafer 300 along the X direction to the other X endpoint, and the ordinate represents the flow velocity of the plating solution on the surface of the wafer 300. As can be seen from the figure, the average flow velocity in the X direction in region a is 0.0035 m / s. The flow velocity results in the Z direction in region a are shown in FIG11c . The abscissa in FIG11c represents the position coordinates extending from the Z lower endpoint located on the edge of the wafer 300 along the Z direction to the other Z endpoint, and the ordinate represents the flow velocity of the plating solution on the surface of the wafer 300. As can be seen from the figure, the average flow velocity in the Z direction in region a is 0.0031 m / s. Please refer to Figure 12b for the flow velocity results in the X direction in region b. The abscissa in Figure 12b is the position coordinate when extending from the X endpoint located on the edge of the wafer 300 along the X direction to the other end point in the X direction, and the ordinate is the plating solution flow velocity on the surface of the wafer 300. As can be seen from the figure, the average flow velocity in the X direction in region b is 0.0014 m / s. Please refer to Figure 12c for the flow velocity results in the Z direction in region b. The abscissa in Figure 12c is the position coordinate when extending from the lower end point of the Z located on the edge of the wafer 300 along the Z direction to the other end point in the Z direction, and the ordinate is the plating solution flow velocity on the surface of the wafer 300. As can be seen from the figure, the average flow velocity in the Z direction in region b is 0.0021 m / s.

[0070] Experimental data shows that when the plating solution is stirred using the stirring mechanism 600 of the prior art, the plating solution flow rate and electric field strength in the area corresponding to the wafer notch are relatively high, which easily causes the plating height to be too high around the wafer notch. However, the stirring mechanism 200 of the present invention can significantly reduce the plating solution flow rate and electric field strength in the area corresponding to the wafer notch, thereby suppressing the plating height around the wafer notch and making the plating height on the wafer surface more uniform. Taking a certain RDL (redistribution layer) product as an example, the actual required plating height is 4um. When the plating solution is stirred using the stirring mechanism of the prior art, the final plating result is: the plating height around the wafer notch can reach 8um. After adopting the stirring mechanism designed by the present invention, when the wafer notch rotates to the shielding area, the wafer rotation speed is controlled to slow down to 5% of the original speed. The final plating result is: the plating height around the wafer notch can be reduced by 50%, meeting the requirement (plating height of 4um).

[0071] Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A stirring mechanism for electroplating equipment, characterized in that: The stirring mechanism includes a shielding area and a stirring area, wherein the shielding area is used to weaken the flow field in the area; the stirring area includes a plurality of first blades arranged in parallel; wherein, During the wafer electroplating process, when the wafer notch is located in the shielding area, the rotation speed of the wafer is a first rotation speed, and when the wafer notch is located in the stirring area, the rotation speed of the wafer is a second rotation speed, and the first rotation speed is less than the second rotation speed; the shielding area is used to reduce the total amount of metal ions received by the wafer notch in the shielding area.

2. The stirring mechanism according to claim 1, characterized in that: The shielding area includes an area enclosed by a plurality of straight edges connected in sequence and the edge line of the stirring mechanism.

3. The stirring mechanism according to claim 1, characterized in that: The shielding area includes an area enclosed by the curved edge and the edge line of the stirring mechanism.

4. The stirring mechanism according to claim 2 or 3, characterized in that: The shielding area is a closed block structure, and the height of the upper end surface of the shielding area is higher than the height of the upper end surface of the first blade.

5. The stirring mechanism according to claim 1, characterized in that: A stirring unit is disposed in the shielding area, and a stirring force of the stirring unit is weaker than a stirring force of the first paddle.

6. The stirring mechanism according to claim 5, characterized in that: The stirring unit includes a plurality of second blades arranged in parallel, and the stirring force of the second blades is weaker than the stirring force of the first blades.

7. The stirring mechanism according to claim 6, characterized in that: The width of the upper end surface of the second blade is greater than the width of the lower end surface of the second blade.

8. The stirring mechanism according to claim 7, characterized in that: The height of the upper end surface of the second blade is higher than or equal to the height of the upper end surface of the first blade.

9. The stirring mechanism according to claim 2 or 3, characterized in that: The shielding area is a hollow frame structure.

10. The stirring mechanism according to claim 9, characterized in that: The upper end surface of the frame of the shielding area is higher than the upper end surface of the stirring area.

11. An electroplating device for electroplating on a wafer surface, characterized in that: The electroplating equipment comprises the stirring mechanism according to any one of claims 1 to 10, and the electroplating equipment is configured to: during the electroplating process, control the stirring mechanism to move parallel to the wafer to stir the electroplating solution.

12. The electroplating equipment according to claim 11, characterized in that: The electroplating equipment also includes a rotatable wafer holding device, which has a clamp used to fix the wafer, and the relative position of the wafer notch and the clamp is fixed.

13. An electroplating method, characterized in that: include: A stirring mechanism including a shielding area and a stirring area is arranged in the electroplating equipment, wherein the shielding area is used to weaken the flow field in the area, and the stirring area includes a plurality of first blades arranged in parallel; The electroplating device is used to perform electroplating on the surface of a wafer, and the stirring mechanism is controlled to move parallel to the wafer to stir the electroplating solution; When the wafer notch is located in the shielding area, the rotation speed of the wafer is a first rotation speed, and when the wafer notch is located in the stirring area, the rotation speed of the wafer is a second rotation speed, and the first rotation speed is less than the second rotation speed; the shielding area is used to reduce the total amount of metal ions received by the wafer notch in the shielding area.

14. The electroplating method according to claim 13, characterized in that: A rotatable wafer holding device is arranged in the electroplating equipment, and the rotation speed of the wafer is controlled by regulating the rotation speed of the wafer holding device.

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