Stirring mechanism of electroplating equipment, electroplating equipment and electroplating method

Abstract

The invention provides a stirring mechanism of electroplating equipment, the electroplating equipment and an electroplating method, and relates to the technical field of semiconductor manufacturing. The stirring mechanism comprises a shielding area and a stirring area, and the shielding area is used for weakening a flow field of the area; the stirring area comprises a plurality of first paddles which are arranged in parallel; wherein in the wafer electroplating process, when a wafer notch is located in the shielding area, the rotating speed of the wafer is a first rotating speed, when the wafer notch is located in the stirring area, the rotating speed of the wafer is a second rotating speed, and the first rotating speed is smaller than the second rotating speed; the shielding area is used for reducing the total amount of metal ions received by the wafer gap in the shielding area. The shielding area is arranged on the stirring mechanism, and the rotating speed of the wafer is controlled to be reduced in time, so that the total amount of metal ions received by the wafer notch in the shielding area is reduced, and the phenomenon that the electroplating height of the peripheral area of the wafer notch is too high in the electroplating process is avoided.

Description

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 popularization of wafer-level packaging technology, a process requirement for electroplating on a wafer containing a non-electroplating area has been proposed. A typical non-electroplating area is in the wafer notch area. In some requirements, the chip dies on the wafer may be arranged in an asymmetric manner, and irregular non-electroplating areas will also be formed. Take the more common wafer notch as an example of a non-electroplating area. In the electroplating area where the chip is arranged, there will be many openings on the photoresist, and metal will be deposited in the openings. During electroplating, these openings deposited with metal will act as wires. Since there is no chip arranged in the wafer notch as a non-electroplating area, there are no openings on the photoresist and no metal deposition. For the electroplating area and the non-electroplating area, when it is in a uniform electric field, since there is no wire in the non-electroplating area and no current can be generated, it will cause a larger current to be generated in the wire in the surrounding area, which makes the position around the non-electroplating area actually under a greater metal ion density, so its electroplating rate is higher, and the final result is that the electroplating height is higher than other positions. For the wafer-level packaging process, the overall height control is very strict. The higher electroplating height near the wafer notch can easily lead to reduced product yield and production loss. Summary of the invention

[0003] 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.

[0004] In the first aspect, the present invention proposes a stirring mechanism of an electroplating equipment, 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 paddles 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.

[0005] According to a specific implementation method of the embodiment of the present application: the shielding area includes an area enclosed by a plurality of straight edges connected in sequence and an edge line of the stirring mechanism.

[0006] According to a specific implementation method 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.

[0007] According to a specific implementation method 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.

[0008] According to a specific implementation method 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 paddle.

[0009] According to a specific implementation method of the 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.

[0010] 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:

[0011] The height of the upper end surface of the second paddle in the shielding area is higher than or equal to the height of the upper end surface of the first paddle in the stirring area.

[0012] According to a specific implementation method of the embodiment of the present application: the shielding area is a hollow frame structure.

[0013] According to a specific implementation method 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.

[0014] In a second aspect, the present application proposes an electroplating device for electroplating on a wafer surface, the electroplating device comprising 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.

[0015] 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.

[0016] In the third aspect, the present application proposes an electroplating method, comprising: 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 paddles arranged in parallel; using the electroplating equipment provided with the stirring mechanism to electroplate on the surface of a wafer, controlling the stirring mechanism 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 paddles; 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 set in the electroplating equipment, and the rotation speed of the wafer is controlled by adjusting the rotation speed of the wafer holding device.

[0017] The stirring mechanism, electroplating equipment and electroplating method of the electroplating equipment of the present invention reduce the flow rate of the electroplating solution in the shielding area by setting a shielding area on the stirring mechanism, and at the same time, in combination with the process, timely control the rotation speed of the wafer to reduce, so that the time that 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 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 partly 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. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 A schematic diagram of the structure of an electroplating device according to an embodiment of the present invention is shown;

[0020] Figure 2 Another schematic structural diagram of the electroplating equipment according to the embodiment of the present invention is shown;

[0021] Figure 3A schematic diagram of the structure of the region formed by a straight edge of the shielding region of the stirring mechanism and the edge line of the stirring mechanism in Embodiment 1 of the present invention is shown;

[0022] Figure 4 A schematic diagram of the structure of the region formed by two straight edges of the shielding region of the stirring mechanism and the edge line of the stirring mechanism in Embodiment 1 of the present invention is shown;

[0023] Figure 5 A schematic diagram of the region structure formed by three straight sides of the shielding region of the stirring mechanism and the edge line of the stirring mechanism in Embodiment 1 of the present invention is shown;

[0024] Figure 6 A schematic diagram of the region structure formed by the curved edge of the shielding region of the stirring mechanism and the edge line of the stirring mechanism in Embodiment 1 of the present invention is shown;

[0025] Figure 7 A three-dimensional schematic diagram of a stirring mechanism in Embodiment 2 of the present invention is shown;

[0026] Figure 8 A three-dimensional schematic diagram of a stirring mechanism in Embodiment 3 of the present invention is shown;

[0027] Fig. 9 A schematic diagram of the structure of a stirring mechanism in the prior art is shown;

[0028] Fig.10 A schematic diagram showing the electron density detection results on different regions of a wafer corresponding to the stirring mechanism of the prior art and the stirring mechanism of the present invention is shown;

[0029] Fig.11a A schematic diagram showing the position of the detection area a corresponding to the stirring mechanism of the prior art is shown;

[0030] Fig.11b A graph showing the change in flow rate of the electroplating solution in the X and Z directions of a region a of a prior art stirring mechanism during an electroplating process is shown;

[0031] Fig.11c A schematic diagram showing the change of electric field intensity in area a of a stirring mechanism in the prior art during electroplating is shown;

[0032] Fig.12a Shows Figure 4 Schematic diagram of the position of the detection area b corresponding to the shielding area of ​​the stirring mechanism;

[0033] Figure 12b Shows Figure 4 A graph showing the change in flow rate of the electroplating solution in the X and Z directions of the stirring mechanism in the electroplating process in region b; and

[0034] Fig.12c Shows Figure 4Schematic diagram of the change of electric field intensity in area b of the stirring mechanism during the electroplating process. DETAILED DESCRIPTION

[0035] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are 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 creative work are within the scope of protection of the present invention.

[0036] 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 plating solution in the same plating chamber, the present invention proposes a structural design of the stirring mechanism of the electroplating equipment to achieve the different requirements for accurately controlling the total amount of metal ions in the plating solution that different areas of the wafer need to receive, and at the same time combine the control with the rotational speed of the wafer to achieve better control effect.

[0037] Please refer to Figure 1 and Figure 2 , Figure 1 and Figure 2The schematic diagrams of the structure of the electroplating equipment of the embodiment of the present invention at different angles are respectively shown. The electroplating equipment of the 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 contain 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 the embodiment of the present invention, the material of the stirring mechanism 200 is an insulator, such as PVC, PC, CPVC, PPS, PEEK, PTFE and other plastic materials. 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 electroplating solution in the area, reduce the fluidity of the electroplating solution in the area, and reduce the metal ion density of the electroplating solution in the area corresponding to the shielding area 201; the stirring area 202 is composed of a plurality of first blades 203 arranged in parallel, and the gaps between adjacent first blades 203 are for liquid and electric field to pass through. During the wafer electroplating process, when the wafer notch 301 is located in the shielding area 201, the rotation speed of the wafer 300 is a first rotation speed, and when the wafer notch 301 is located in the stirring area 202, the rotation speed of the wafer 300 is a second rotation speed, and the first rotation speed is less than the second rotation 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 rotation speed is less than the second rotation speed, which can ensure that in a complete electroplating process, the time that the wafer notch 301 is in the shielding area 201 becomes longer, 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, and achieving the purpose of uniform electroplating.

[0038] Furthermore, when designing the shielding region 201, the area of ​​the shielding region 201 is larger than the area of ​​the wafer notch 301, so as to ensure that the wafer notch 301 can be completely within the shielding region 201, so as to achieve a better shielding effect. 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 region 202 can better pass through the gap between adjacent first blades 203; the shielding region 201 is designed according to the position and size of the wafer notch 301, so that the area of ​​the shielding region 201 is larger than the area of ​​the wafer notch 301, so as to ensure that the wafer notch 301 can be completely within the shielding region 201. For example, as Figure 2 As shown, 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 .

[0039] refer to Figure 1The electroplating equipment of the embodiment of the present invention further 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 known according to 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, which 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.

[0040] 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.

[0041] Example 1

[0042] In this embodiment, the shielding area 201 is a closed block structure. Specifically, the shielding area 201 may include an area formed by a number of straight edges connected in sequence and the edge line of the stirring mechanism. The meaning of "a number" in the embodiment of the present invention is an integer greater than or equal to 1; the shielding area 201 may also be an area formed by a curved edge and the edge line of the stirring mechanism.

[0043] For example, please refer to Figure 3 , illustrating that the shielding area 201 is an area enclosed by a plurality of straight edges connected in sequence and the edge line of the stirring mechanism, and the shielding area 201 formed when the number of straight edges is 1, is Figure 3 It can be seen that 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 occlusion region 201 formed when the number of straight edges is 2, Figure 4It can be known that the two straight edges 4011a and 4011b are connected in sequence, and then the free end of the straight edge 4011a is connected to the stirring mechanism edge line 4012, and the free end of the straight edge 4011b is connected to the stirring mechanism edge line 4012, and the closed area formed by the two straight edges 4011a and 4011b and the stirring mechanism edge line 4012 is the shielding area 201, which is a closed block structure. Wherein, the free end refers to an end of the straight edges 4011a and 4011b respectively located at the outside. It can be understood that although described as a line or edge, the stirring mechanism and the shielding area 2011 are structures with a certain thickness, so the stirring mechanism edge line represents that the cross section of the stirring mechanism is a vertical curved surface or plane of the edge line, and the straight edge represents that the cross section of the shielding area is a vertical plane of a straight line.

[0044] Please refer to Figure 5 , illustrating the occlusion region 201 formed when the number of straight edges is 3; Figure 5 It can be seen that 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 together form an enclosed closed area, which is the shielding area 201, and the area is a closed block structure.

[0045] In other embodiments, the shielding area 201 is an area enclosed by the curved edge and the edge line of the stirring mechanism.

[0046] Please refer to Figure 6 , illustrating the shielding area 201 formed by the curved edge 6011 and the edge line 6012 of the stirring mechanism; Figure 6 It can be seen that the two ends of the straight edge 6011 are directly connected to the edge line 6012 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. It should be understood that the above is only an example, and the number of straight edges is not limited in the embodiment 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 embodiment of the present invention. There is no specific limitation on the specific shape of the curved edge, which can be an arc or a corrugated curve.

[0047] 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 decelerate so that the wafer notch 301 is located in the The time of shielding area 201 is prolonged, the total amount of metal ions received by the surrounding area of ​​wafer notch 301 is reduced, and then the electroplating height around wafer notch 301 is reduced, so that the overall electroplating height of wafer 300 is kept uniform; at the same time, shielding area 201 is a closed block structure made of insulating material, which will prevent the electric field below shielding area 201 from being transmitted to the top of shielding area 201 to act on wafer 300, therefore, the current density in shielding area 201 is also small, and during electroplating, the coating on the area corresponding to the shielding area 201 on wafer 300 is also reduced accordingly. When wafer notch 301 is in shielding area 201 for a long time, the effect of suppressing the electroplating height around wafer notch 301 is more obvious than that of non-notch area, thereby ensuring that the overall electroplating height of wafer 300 is kept uniform. It should be understood that in other embodiments, the relative height between the upper end surface of shielding area 201 and the upper end surface of first paddle 203 in stirring area 202 can be set according to actual needs.

[0048] During the electroplating process, when the wafer notch 301 is located in the shielding area 201, the shielding area 201 shields 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 to make the wafer notch 301 spend more time in the shielding area 201. 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 solution is weak, so that the fluidity of the plating solution in the shielding area 201 is weaker than the fluidity of the plating solution 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 electroplating height in the area surrounding the wafer notch 301.

[0049] Example 2

[0050] 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. For example, 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, such as Figure 7As shown. This embodiment is described by taking the example that the stirring unit is a plurality of parallel blades and the second blade 204 in the shielding area 201 is parallel to the first blade 203 in the stirring area 202. 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 shield the electric field while weakening the flow 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 protection scope 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.

[0051] 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 .

[0052] In some embodiments, when the upper end surface of the second paddle 204 and the upper end surface of the first paddle 203 are located on the same horizontal plane, the stirring force achieved by the cross-sectional shape of the second paddle 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 paddle 204 weaker than the stirring force of the first blade 203.

[0053] 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 smaller 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 located in the shielding area 201 is prolonged, the metal ion mass transfer rate is reduced, and the electroplating height of the surrounding area of ​​the wafer notch 301 is reduced, so that the overall electroplating height of the wafer 300 is kept 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.

[0054] The height of the upper end surface of the second blade 204 can be set according to actual needs.

[0055] Example 3

[0056] The structure of the stirring mechanism of Example 3 is slightly different from that of 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 set in the shielding area 201 of the hollow frame structure design. In this embodiment, the shielding area 201 is only formed by the edge line of the stirring mechanism and the curved edge or a plurality of straight edges connected in sequence. The shape of the shielding area 201 formed by the enclosed is the same as that in Example 1. Figure 3-Figure 6 As shown, no further details are given here. If 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 making the mass transfer rate of metal ions in the plating solution lower than that in the stirring area 202. Combined with the control method of decelerating the wafer 300 when the wafer notch 301 rotates into the shielding area 201, the time that the wafer notch 301 is located in the shielding area 201 is prolonged, the mass transfer rate of metal ions 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 is kept uniform.

[0057] For further information, please refer to Figure 8 , the upper end surface of the edge frame of the shielding area 201 is higher than the upper end surface of the paddle in the stirring area 202, so as to prevent the rapid exchange of the plating solution in the stirring area 202 with the plating solution in the shielding area 201. It should be understood that the height of the upper end surface of the edge frame of the shielding area 201 can also be selected to be equal to the height of the upper end surface of the paddle in the stirring area 202.

[0058] When setting specifically, please refer to Embodiment 1 for the position and shape of the shielding area 201, which will not be described in detail here.

[0059] The present application also provides an electroplating method using an electroplating device for electroplating, comprising:

[0060] Step S1: 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;

[0061] Step S2: electroplating on the surface of the wafer using electroplating equipment, controlling the stirring mechanism 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.

[0062] The setting of the rotation speed of the wafer in the above steps can be controlled by a controller in the electroplating equipment.

[0063] Furthermore, 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. Specifically, the rotation speed of the wafer holding device can be adjusted by a controller of the electroplating equipment.

[0064] In order to reflect the effect achieved by the present invention, the shielding area 201 of the stirring mechanism 200 is taken as an example to illustrate the closed block structure. Fig. 9 and Figure 4 , Fig. 9 The schematic diagram of the structure of the stirring mechanism in the prior art is shown.

[0065] Under the same electroplating process conditions, the Fig. 9 and Figure 4 The stirring mechanism detects the charge density in the plating solution below the wafer. For specific results, please refer to Fig.10 , Fig.10 A schematic diagram showing the charge density detection results on different regions of a wafer corresponding to the stirring mechanism of the prior art and the stirring mechanism of the present invention is shown. Fig.10In the figure, the horizontal axis is the coordinate of the wafer 300 extending from one edge to the other side along the diameter direction. It can be known that the size of the wafer 300 in this embodiment is 300 mm. Fig.10 The ordinate is the charge density value of the lower surface of the wafer 300; line a is the measurement result of the charge density of the wafer at different positions during the electroplating process using the stirring mechanism of the prior art; line b is the measurement result of the charge density of the wafer at different positions during the electroplating process using the stirring mechanism of the present invention. Fig.10 As shown, 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, and 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 charge density in the shielding area 201 of the stirring mechanism 200 can be significantly reduced. 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.

[0066] The plating solution flow rate in the same area of ​​the stirring mechanism 200 with the shielding area and the stirring mechanism 600 without the shielding area is further detected. Specifically, when the wafer 300 is placed in the wafer holding device 400, the central axis of the wafer notch 301 is taken as the center, and the area with the same area as the shielding area 201 is demarcated as the detection area. For the detection area corresponding to the stirring mechanism of the prior art, please refer to Fig.11a , area a is the detection area; for the detection area corresponding to the stirring mechanism of the present invention, please refer to Fig.12a , area b is the detection area. Detect the flow velocity in the X direction and the flow velocity in the Z direction in area a and area b. For the flow velocity result in the X direction in area a, please refer to Fig.11b , Fig.11b The horizontal axis in the figure is the position coordinate when the end point X located on the edge of the wafer 300 extends along the X direction to the other end point in the X direction, and the vertical axis is the flow rate of the plating solution on the surface of the wafer 300; it can be seen from the figure that the average flow rate in the X direction in area a is 0.0035m / s; the flow rate results in the Z direction in area a can be referred to Fig.11c , Fig.11c The horizontal axis in the figure is the position coordinate when the lower end point of Z located on the edge of the wafer 300 extends along the Z direction to the other end point in the Z direction, and the vertical axis is the flow rate of the plating solution on the surface of the wafer 300; it can be seen from the figure that the average flow rate in the Z direction in area a is 0.0031m / s. For the flow rate results in the X direction in area b, please refer to Figure 12b , Figure 12bThe horizontal axis in the figure is the position coordinate when the end point X located on the edge of the wafer 300 extends along the X direction to the other end point in the X direction, and the vertical axis is the flow rate of the plating solution on the surface of the wafer 300; it can be seen from the figure that the average flow rate in the X direction in area b is 0.0014m / s; please refer to the flow rate results in the Z direction in area b Fig.12c , Fig.12c The horizontal axis is the position coordinate when the lower end point of Z located on the edge of the wafer 300 extends along the Z direction to the other end point in the Z direction, and the vertical axis is the flow rate of the plating solution on the surface of the wafer 300; it can be seen from the figure that the average flow rate in the Z direction in area b is 0.0021m / s.

[0067] It is known from the experimental data that when the plating solution is stirred by the stirring mechanism 600 of the prior art, the flow rate and electric field strength of the plating solution in the area corresponding to the wafer notch are relatively high, and the plating height around the wafer notch is easily too high; while the stirring mechanism 200 of the present invention can significantly reduce the flow rate and electric field strength of the plating solution 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 (rewiring layer) product as an example, the actual required plating height is 4um. When the plating solution is stirred by the stirring mechanism of the prior art, the final plating result is: the plating height around the wafer notch can reach 8um; and after the stirring mechanism designed by the present invention is adopted, when the wafer notch rotates to the shielding area, the rotation speed of the wafer is controlled to be decelerated to 5% of the original speed, and the final plating result is: the plating height around the wafer notch can be reduced by 50%, meeting the requirement (plating height of 4um).

[0068] 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 substitutions for some of the technical features therein; and these modifications or substitutions do not make the essence of the corresponding technical solutions 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 described in 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.

Images