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

Agitating mechanism of electroplating equipment, electroplating equipment and electroplating method TECHNICAL FIELD

[0001] The present application relates to the technical field of semiconductor manufacturing, in particular to an agitating mechanism of electroplating equipment, electroplating equipment and electroplating method. BACKGROUND

[0002] With the popularization of wafer level packaging process, the process requirement of electroplating on the wafer containing non-electroplating area is proposed. The typical non-electroplating area is the wafer notch area. In some requirements, the chip die on the wafer can be arranged in an asymmetric manner, which also forms an irregular non-electroplating area. Taking the wafer notch as a more common non-electroplating area as an example. In the electroplating area arranged with chips, there are many openings on the photoresist, and metal will be deposited in the openings. When electroplating is performed, these openings with deposited metal will act as wires. Since the wafer notch as a non-electroplating area does not arrange chips, there are no openings on the photoresist, and no metal is deposited. For the electroplating area and the non-electroplating area, when they are in a uniform electric field, the non-electroplating area cannot generate current because there is no wire in the non-electroplating area, which will cause a larger current to flow in the wires in the surrounding area of the non-electroplating area. This makes the position around the non-electroplating area actually under a larger metal ion density, so the 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, and the higher electroplating height near the wafer notch can easily lead to product yield reduction and yield loss.

[0003] SUMMARY

[0004] The purpose of the present application is to provide an agitating mechanism of electroplating equipment, electroplating equipment and electroplating method to improve the uniformity of the electroplating height.

[0005] In a first aspect, the present application provides an agitating mechanism of electroplating equipment, the agitating mechanism comprising a shielding area and an agitating area, the shielding area being used to weaken the flow field in the area; the agitating area comprising a plurality of first paddles arranged in parallel; wherein, during the electroplating process of the wafer, 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 agitating area, the rotation speed of the wafer is a second rotation speed, the first rotation speed being less than the second rotation speed; the shielding area is used to reduce the rotation speed of the wafer, 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 manner of an embodiment of the present application: the shielding area comprises an area enclosed by a plurality of straight edges connected in sequence and an edge line of the agitating mechanism.

[0007] According to an implementation manner of the embodiment of the present application, the shielding area comprises an area enclosed by a curved side and a stirring mechanism edge line.

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

[0009] According to an implementation manner of the embodiment of the present application, a stirring unit is arranged in the shielding area, and a stirring force of the stirring unit is weaker than a stirring force of the first paddle.

[0010] According to an implementation manner of the embodiment of the present application, the stirring unit comprises a plurality of second paddles arranged in parallel, and a stirring force of the second paddle in the shielding area is weaker than a stirring force of the first paddle in the stirring area.

[0011] According to an implementation manner of the embodiment of the present application, a width of an upper end surface of the second paddle in the shielding area is greater than a width of a lower end surface of the second paddle.

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

[0013] According to an implementation manner of the embodiment of the present application, the shielding area is a hollow frame structure.

[0014] According to an implementation manner of the embodiment of the present application, an upper end surface of the frame of the shielding area is higher than an upper end surface of the stirring area.

[0015] In a second aspect, the present application provides an electroplating device for electroplating on a wafer surface, the electroplating device comprising the stirring mechanism described above, and the electroplating device is configured to control the stirring mechanism to move parallel to the wafer during the electroplating process to stir the electroplating solution.

[0016] According to an implementation manner of the embodiment of the present application, the electroplating device further comprises a rotatable wafer holding device, the wafer holding device is rotatable, the wafer holding device has a clamp, the clamp is used to fix the wafer on the wafer holding device to rotate with the clamp, and a relative position of the wafer gap and the clamp is fixed.

[0017] In a third aspect, the application provides a plating method, comprising: providing a stirring mechanism comprising a shielding area and a stirring area in a plating device, wherein the shielding area is used to weaken the flow field in the area, and the stirring area comprises a plurality of first paddles arranged in parallel; using the plating device provided with the stirring mechanism to perform plating on a wafer surface, controlling the stirring mechanism to move parallel to the wafer, and stirring 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 paddles arranged in parallel; when the wafer gap is located in the shielding area, the rotation speed of the wafer is a first rotation speed; when the wafer gap 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 gap in the shielding area; when the wafer gap is located in the shielding area, the rotation speed of the wafer is reduced, so that the total amount of metal ions received by the wafer gap in the shielding area is reduced. According to a specific implementation manner of an embodiment of the application, a rotatable wafer holding device is provided in the plating device, and the rotation speed of the wafer is controlled by adjusting the rotation speed of the wafer holding device.

[0018] The stirring mechanism of the plating device, the plating device and the plating method provided by the application weaken the flow rate of the plating solution in the shielding area by providing the shielding area on the stirring mechanism, and reduce the rotation speed of the wafer in time during the process, so that the time of the wafer gap in the shielding area is prolonged, the total amount of metal ions received by the wafer gap in the shielding area is reduced, and the phenomenon of over-high plating height of the wafer gap peripheral area in the plating process is avoided. Other features and advantages of the application will be described in the following description, and some will become apparent from the description, or will be understood by those skilled in the art from the description. The objects and other advantages of the application can be achieved and obtained by the structures indicated in the description and the drawings.

[0019] SUMMARY

[0020] The features and performances of the application are further described by the following embodiments and drawings.

[0021] Fig. 1 shows a schematic structural diagram of a plating device according to an embodiment of the application;

[0022] Fig. 2 shows another schematic structural diagram of a plating device according to an embodiment of the application;

[0023] Fig. 3 shows a schematic structural diagram of an area enclosed by a straight edge of a shielding area of a stirring mechanism and an edge line of the stirring mechanism according to an embodiment 1 of the application;

[0024] Fig. 4 shows a schematic structural diagram of an area enclosed by two straight edges of a shielding area of a stirring mechanism and an edge line of the stirring mechanism according to an embodiment 1 of the application;

[0025] Figure 5 shows a schematic diagram of the area structure formed by the three straight edges of the shielding area of the stirring mechanism of embodiment 1 and the edge line of the stirring mechanism;

[0026] Figure 6 shows a schematic diagram of the area structure formed by the curved edge of the shielding area of the stirring mechanism of embodiment 1 and the edge line of the stirring mechanism;

[0027] Figure 7 shows a schematic diagram of the stirring mechanism of embodiment 2;

[0028] Figure 8 shows a schematic diagram of the stirring mechanism of embodiment 3;

[0029] Figure 9 shows a schematic diagram of the stirring mechanism of the prior art;

[0030] Figure 10 shows a schematic diagram of the electron density detection results of different areas on the wafer by the stirring mechanism of the prior art and the stirring mechanism of the present application;

[0031] Figure 11a shows a schematic diagram of the position of the detection area a corresponding to the stirring mechanism of the prior art;

[0032] Figure 11b shows a diagram of the variation of the flow rate of the electroplating solution in the X and Z directions of area a during the electroplating process by the stirring mechanism of the prior art;

[0033] Figure 11c shows a schematic diagram of the variation of the electric field intensity of area a during the electroplating process by the stirring mechanism of the prior art;

[0034] Figure 12a shows a schematic diagram of the position of the detection area b corresponding to the shielding area of the stirring mechanism of Figure 4;

[0035] Figure 12b shows a diagram of the variation of the flow rate of the electroplating solution in the X and Z directions of area b during the electroplating process by the stirring mechanism of Figure 4; and

[0036] Figure 12c shows a schematic diagram of the variation of the electric field intensity of area b during the electroplating process by the stirring mechanism of Figure 4.

[0037] Preferred embodiments of the present application

[0038] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some but not all of the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0039] Through actual observation and summary of the electroplating process and results, the inventor finds that in order to adapt to the situation that different areas of a wafer need to correspond to different flowabilities of electroplating solution in the same electroplating cavity, the present application proposes to design the structure of the stirring mechanism of the electroplating equipment to achieve the different needs of the total amount of metal ions received by different areas of the wafer, and to control the rotation speed of the wafer to achieve better control effect.

[0040] Please refer to FIG. 1 and FIG. 2, which respectively show the structural schematic diagram of the electroplating equipment at different angles according to the embodiment of the present application. The electroplating equipment according to the embodiment of the present application comprises an electroplating cavity 100 and a stirring mechanism 200, and the stirring mechanism 200 is arranged in the electroplating cavity 100. The electroplating cavity 100 is used to contain electroplating solution. In 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 application, the material of the stirring mechanism 200 is an insulator, such as PVC, PC, CPVC, PPS, PEEK, PTFE and the like. The stirring mechanism 200 comprises 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 this area, and reduce the flowability of the electroplating solution in this area, so that the metal ion density of the electroplating solution in the area corresponding to the shielding area 201 is reduced. The stirring area 202 is composed of a plurality of first paddles 203 arranged in parallel, and the gap between adjacent first paddles 203 is provided for liquid and electric field to pass through. In the wafer electroplating process, when the wafer gap 301 is located in the shielding area 201, the rotation speed of the wafer 300 is the first rotation speed, and when the wafer gap 301 is located in the stirring area 202, the rotation speed of the wafer 300 is the 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 gap 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 of the wafer gap 301 in the shielding area 201 is longer, the ion exchange rate around the wafer gap 301 will be reduced, thereby avoiding the high electroplating height near the wafer gap 301, and achieving the purpose of uniform electroplating.

[0041] Further, when designing the shielding area 201, the area of the shielding area 201 is greater than the area of the wafer gap 301 to ensure that the wafer gap 301 can be entirely in 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 wafer 300 are matched to set the size and shape of the stirring mechanism 200, so that the electroplating solution and electric field in the stirring area 202 can better pass through the gap between the adjacent first paddles 203; the shielding area 201 is designed according to the position and size of the wafer gap 301, so that the area of the shielding area 201 is greater than the area of the wafer gap 301 to ensure that the wafer gap 301 can be entirely in the shielding area 201. For example, as shown in FIG. 2, when the wafer gap 301 is arranged at the edge of the wafer 300, the shielding area 201 is correspondingly arranged at the edge of the stirring mechanism 200, and the area of the shielding area 201 is greater than the area of the wafer gap 301.

[0042] Referring to FIG. 1, the electroplating device of the embodiment of the present application further comprises 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 to rotate with the wafer holding device 400. The relative position between the wafer gap 301 on the wafer 300 and the wafer holding device 400 is fixed, so the position of the wafer gap 301 can be known according to the rotation position of the wafer holding device 400. In the process of electroplating, the wafer holding device 400 drives the wafer 300 to rotate. The rotation speed can be from 0.1 rpm to 500 rpm, which can be determined according to actual conditions. The position of the wafer gap 301 is tracked according to the rotation speed of the wafer holding device 400, the rotation speed of the wafer 300 is controlled to be the second rotation speed when the wafer gap 301 is in the stirring area 202, and the rotation speed of the wafer 300 is reduced when the wafer gap 301 starts to enter the shielding area 201, so that the wafer 300 rotates at the first rotation speed. The reduction of the rotation speed of the wafer 300 reduces the total amount of metal ions received by the wafer gap 301 in the shielding area 201, avoiding the occurrence of the phenomenon that the electroplating height of the peripheral area of the wafer gap 301 is too high due to the greater metal ion density.

[0043] In order to achieve the above-mentioned purposes, the specific structure of the stirring mechanism 200 is optimized in the embodiment of the present application, which will be described in detail as follows.

[0044] Embodiment 1

[0045] In the embodiment, the shielding area 201 is a closed block structure. Specifically, the shielding area 201 can include an area enclosed by a plurality of straight edges connected in sequence and the edge line of the stirring mechanism. In the embodiment, the plurality of edges means an integer greater than or equal to 1. The shielding area 201 can also be an area enclosed by curved edges and the edge line of the stirring mechanism.

[0046] For example, referring to FIG. 3, 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 number of straight edges is 1. As shown in FIG. 3, the two ends of the straight edge 3011 are directly connected to the edge line 3012 of the stirring mechanism, forming a closed enclosed area, i.e., the shielding area 201. In the embodiment, the shielding area 201 is a closed block structure. Referring to FIG. 4, the number of straight edges is 2. As shown in FIG. 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 two straight edges 4011a and 4011b and the edge line 4012 of the stirring mechanism form a closed enclosed area, i.e., the shielding area 201. The area is a closed block structure. The free end refers to the end of the straight edge 4011a and 4011b located on the outside. It can be understood that although it is described as a line or edge, the stirring mechanism and the shielding area 201 are structures with a certain thickness, so the edge line of the stirring mechanism represents the vertical curved surface or plane of the cross section of the stirring mechanism, and the straight edge represents the vertical plane of the cross section of the shielding area.

[0047] Referring to FIG. 5, the number of straight edges is 3. As shown in FIG. 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 the straight edge 5011b is connected to one end of the straight edge 5011c, the other end of the straight edge 5011c is connected to the edge line 5012 of the stirring mechanism, and the straight edges 5011a, 5011b and 5011c and the edge line 5012 of the stirring mechanism together form a closed enclosed area, i.e., the shielding area 201. The area is a closed block structure.

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

[0049] Please refer to FIG. 6, which illustrates the shielding area 201 enclosed by the curved edge 6011 and the stirring mechanism edge line 6012. As shown in FIG. 6, the two ends of the straight edge 6011 directly connect with the stirring mechanism edge line 6012, forming a closed enclosed area, i.e., 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 application. When the number of straight edges is greater than or equal to 2, the included angle formed by two connected straight edges is not limited in the embodiments of the present application. The specific shape of the curved edge is not limited, which can be an arc or a corrugated curve.

[0050] Further, 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 of the stirring area 202, i.e., in 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. Therefore, in the process of stirring the electroplating solution, the space between the shielding area 201 and the wafer 300 is small, and the electroplating solution that can be accommodated is small. At the same time, because the flowability of the electroplating solution in the area corresponding to the shielding area 201 is smaller than the flowability of the electroplating solution in the area corresponding to the stirring area 202, the exchange rate of metal ions in the electroplating solution will be lower than that of the stirring area 202. When the wafer gap 301 rotates to this area, the wafer 300 is controlled to slow down, so that the wafer gap 301 is located in the shielding area 201 for a longer time, reducing the total amount of metal ions received by the peripheral area of the wafer gap 301, thereby reducing the electroplating height of the peripheral area of the wafer gap 301, and ensuring the uniformity of the overall electroplating height of the wafer 300. 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 acting on the wafer 300 above the shielding area 201. Therefore, the current density in the shielding area 201 is also small, and the plating layer on the area on the wafer 300 corresponding to the shielding area 201 is also reduced during electroplating. When the wafer gap 301 is in the shielding area 201 for a long time, the effect of suppressing the electroplating height of the peripheral area of the wafer gap 301 is more obvious than that of the non-gap area, thereby ensuring the uniformity of the overall electroplating height of the wafer 300. It should be understood that in other embodiments, the relative height of the upper end surface of the shielding area 201 and the upper end surface of the first paddle 203 of the stirring area 202 can be set according to actual needs.

[0051] In 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, so that the wafer notch 301 stays in the shielding area 201 for a longer time. Relatively speaking, the plating layer on the area corresponding to the wafer 300 shielded by the shielding area 201 will be less, so that the electroplating height of the peripheral area of the wafer notch 301 is controllable. Because the block structure has a closed characteristic, when the electric field in the electroplating cavity 100 passes through the shielding area 201 of the closed block structure, it will be blocked. Especially when the stirring mechanism in the embodiment of the present application is made of insulating material, the electric field cannot pass through the shielding area 201, so that the total electric quantity received by the peripheral area of the wafer notch 301 in the shielding area 201 is reduced, thereby forming the effect of suppressing the electroplating height of the peripheral area of the wafer notch 301. At the same time, when the shielding area 201 is a closed block structure, the stirring effect of the electroplating liquid is weak, so that the flowability of the electroplating liquid in the shielding area 201 is weaker than that in the stirring area 202, which reduces the total amount of metal ions received by the wafer notch 301 in the shielding area 201, and further suppresses the electroplating height of the peripheral area of the wafer notch 301.

[0052] Example 2

[0053] The structure of the stirring mechanism of embodiment 2 is slightly different from that of embodiment 1. The stirring unit is arranged in the shielding area, and the stirring force of the stirring unit is weaker than that of the paddle in the stirring area. For example, the structure of the stirring unit can be multiple parallel paddles, and the paddles in the shielding area can be perpendicular to the paddles in the stirring area, or parallel to the paddles in the stirring area, as shown in FIG. 7. This embodiment takes the case where the stirring unit is multiple parallel paddles and the second paddle 204 in the shielding area 201 is parallel to the first paddle 203 in the stirring area 202 as an example. In order to make the stirring force of the second paddle 204 weaker than that of the first paddle 203, it can be designed from multiple factors, including but not limited to: the cross-sectional shape of the second paddle 204, the gap between adjacent second paddles 204, etc. Further, the width of the upper end surface of the second paddle 204 is greater than the width of the lower end surface of the second paddle 204, so as to weaken the flow field while shielding the electric field. For example, the cross-sectional shape of the second paddle 204 includes but is not limited to: inverted trapezoidal or inverted "T" shape or inverted triangular shape, etc., and the distance between adjacent second paddles 204 can be selected to be less than the distance between adjacent first paddles 203, or greater than or equal to the distance between adjacent first paddles 203. In this embodiment, various factors affecting the stirring force of the stirring unit are not specifically limited, as long as the second paddle 204 in the shielding area 201 has a weaker stirring force than the first paddle 203 in the stirring area 202. In the actual processing and manufacturing process, the first paddle 203 and the second paddle 204 can be designed in segments and processed and manufactured integrally, or they can be processed and manufactured separately and then installed and fixed.

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

[0055] In some embodiments, when the upper end surface of the second paddle 204 is located at the same horizontal plane as the upper end surface of the first paddle 203, the cross-sectional shape of the second paddle 204, the gap between adjacent second paddles 204, or both can be adjusted and designed to achieve a stirring force that is weaker than that of the first paddle 203.

[0056] In some embodiments, the upper end surface of the second paddle 204 is higher than the upper end surface of the first paddle 203, i.e. during the process, the upper end surface of the second paddle 204 is closer to the wafer 300 than the upper end surface of the first paddle 203. The distance between the second paddle 204 and the wafer 300 is smaller than the distance between the first paddle 203 and the wafer 300, so that the flowability of the electroplating solution in the shielding area 201 is smaller than the flowability of the electroplating solution in the stirring area 202 during stirring of the electroplating solution by the stirring mechanism 200, and thus the exchange rate of metal ions in the electroplating solution in the shielding area 201 is lower than the exchange rate of metal ions in the electroplating solution in the stirring area 202. When the wafer gap 301 rotates into the shielding area 201, the wafer 300 is controlled to rotate at the first rotation speed, so that the wafer gap 301 stays in the shielding area 201 for a longer time, the mass transfer rate of metal ions is reduced, and thus the electroplating height of the peripheral area of the wafer gap 301 is reduced, and the overall electroplating height of the wafer 300 is kept uniform. It should be understood that when the upper end surface of the second paddle 204 is higher than the upper end surface of the first paddle 203, the cross-sectional shape of the second paddle 204 and the first paddle 203, the gap between adjacent paddles, or a combination of both 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 the stirring force of the second paddle 204 being weaker than the stirring force of the first paddle 203.

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

[0058] Embodiment 3

[0059] The structure of the stirring mechanism of Embodiment 3 is slightly different from that of Embodiment 1. The shielding area 201 in Embodiment 1 is a solid structure. The shielding area 201 is a hollow frame structure, and no structure is arranged in the shielding area 201 designed by the hollow frame structure. 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 edge line is shown in Figs. 3-6 of Embodiment 1, which is not repeated here. No structure similar to a paddle is arranged in the shielding area 201, so the stirring force inside the shielding area 201 is weaker than the stirring force of the stirring area 202, and thus the flowability of the electroplating solution in the shielding area 201 is also weaker than the flowability of the electroplating solution in the stirring area 202, and thus the mass transfer rate of metal ions in the electroplating solution is lower than that in the stirring area 202. When the wafer gap 301 rotates into the shielding area 201, the wafer 300 is controlled to rotate at the first rotation speed, so that the wafer gap 301 stays in the shielding area 201 for a longer time, the mass transfer rate of metal ions is reduced, and thus the electroplating height of the peripheral area of the wafer gap 301 is reduced, and the overall electroplating height of the wafer 300 is kept uniform.

[0060] Furthermore, referring to Figure 8, the upper surface of the edge frame of the shielding area 201 is higher than the upper surface of the impeller in the stirring area 202 to prevent rapid exchange between the electroplating solution in the stirring area 202 and the electroplating solution in the shielding area 201. It should be understood that the height of the upper surface of the edge frame of the shielding area 201 can also be chosen to be equal to the height of the upper surface of the impeller in the stirring area 202.

[0061] For specific settings, please refer to Example 1 for the position and shape of the occlusion area 201, which will not be elaborated here.

[0062] This application also provides an electroplating method using electroplating equipment, comprising:

[0063] Step S1: A stirring mechanism including a shielding area and a stirring area is set 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;

[0064] Step S2: Electroplating is performed on the wafer surface using electroplating equipment. 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 wafer rotation speed is the first rotation speed. When the wafer notch is located in the stirring area, the wafer rotation speed is the second rotation speed. 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 wafer rotation speed setting in the above steps can be controlled by the controller in the electroplating equipment.

[0066] Furthermore, a rotatable wafer holding device is installed in the electroplating equipment, and the wafer rotation speed 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 the controller of the electroplating equipment.

[0067] To illustrate the effects achieved by the present invention, the example of the shielding area 201 of the stirring mechanism 200 being a closed block structure is provided. Please refer to Figures 9 and 4. Figure 9 shows a schematic diagram of the structure of the stirring mechanism in the prior art.

[0068] Under the same electroplating process condition, the stirring mechanism of Figure 9 and the stirring mechanism of Figure 4 are respectively placed in the electroplating cavity, and the charge density in the electroplating solution under the wafer is detected, and the specific results are shown in Figure 10, which shows the charge density detection results of the wafer corresponding to different areas of the stirring mechanism of the prior art and the stirring mechanism of the present application. In Figure 10, the abscissa is the coordinate of the wafer 300 extending from one edge to the other side along the diameter direction, and it can be known that the size of the wafer 300 in the embodiment is 300 mm; the ordinate 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 of the wafer corresponding to different positions in the electroplating process using the stirring mechanism of the prior art; and line b is the measurement result of the charge density of the wafer corresponding to different positions in the electroplating process using the stirring mechanism of the present application. As shown in Figure 10, when the wafer 300 extends from one edge to the other side along the diameter direction, the line a and the line b have intersection points, and the area between the first intersection point A and the second intersection point B is the shielding area 201 corresponding to the wafer notch 301, and the charge density of the line b in the shielding area 201 is obviously smaller than that of the line a, which indicates that the stirring mechanism 200 after the shielding area 201 is set, the charge density in the shielding area 201 can be significantly reduced, and in the electroplating process, when the wafer notch 301 enters the shielding area 201, the total electric quantity received will be reduced, thereby reducing the electroplating height of the peripheral area of the wafer notch 301.

[0069] Further, the flow rate of the plating solution in the same area of the stirring mechanism 200 provided with the shielding area and the stirring mechanism 600 not provided with the shielding area was detected. Specifically, when the wafer 300 was placed in the wafer holding device 400, a region with the same area as the shielding area 201 was defined as a detection area with the center axis of the wafer gap 301 as the center. The detection area corresponding to the prior art stirring mechanism is shown in Fig. 11a, and the area a is the detection area. The detection area corresponding to the stirring mechanism of the present application is shown in Fig. 12a, and the area b is the detection area. The flow rate in the X direction and the flow rate in the Z direction in the areas a and b were detected. The flow rate in the X direction in the area a is shown in Fig. 11b, in which the abscissa is the position coordinate of the extension of the X end point on the edge of the wafer 300 to the other end point in the X direction, and the ordinate is the flow rate of the plating solution on the surface of the wafer 300. As shown in the figure, the average flow rate in the X direction in the area a is 0.0035 m / s. The flow rate in the Z direction in the area a is shown in Fig. 11c, in which the abscissa is the position coordinate of the extension of the lower end point of Z on the edge of the wafer 300 to the other end point in the Z direction, and the ordinate is the flow rate of the plating solution on the surface of the wafer 300. As shown in the figure, the average flow rate in the Z direction in the area a is 0.0031 m / s. The flow rate in the X direction in the area b is shown in Fig. 12b, in which the abscissa is the position coordinate of the extension of the X end point on the edge of the wafer 300 to the other end point in the X direction, and the ordinate is the flow rate of the plating solution on the surface of the wafer 300. As shown in the figure, the average flow rate in the X direction in the area b is 0.0014 m / s. The flow rate in the Z direction in the area b is shown in Fig. 12c, in which the abscissa is the position coordinate of the extension of the lower end point of Z on the edge of the wafer 300 to the other end point in the Z direction, and the ordinate is the flow rate of the plating solution on the surface of the wafer 300. As shown in the figure, the average flow rate in the Z direction in the area b is 0.0021 m / s.

[0070] Through the experimental data, it is known that when the plating solution is stirred by the stirring mechanism 600 of the prior art, the flow rate and the electric field intensity of the plating solution corresponding to the wafer notch area are relatively high, and the plating height of the wafer notch periphery is prone to be too high; and the stirring mechanism 200 of the present application can significantly reduce the flow rate and the electric field intensity of the plating solution corresponding to the wafer notch area, thereby inhibiting the plating height of the wafer notch periphery, and making the plating height of the wafer surface more uniform. Taking a certain RDL (re-distribution layer) product as an example, the actual requirement for the plating height is 4 um, and when the plating solution is stirred by the stirring mechanism of the prior art, the final plating result is that the plating height of the wafer notch periphery can reach as high as 8 um; and after the stirring mechanism designed by the present application is used, when the wafer notch rotates to the shielding area, the rotation speed of the wafer is controlled to reduce to 5% of the original speed, and the final plating result is that the plating height of the wafer notch periphery can be reduced by 50%, reaching the requirement (the plating height is 4 um).

[0071] Although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those skilled in the art that the technical solutions recorded in the foregoing embodiments can still be modified, or some technical features can be replaced by equivalent ones; and these modifications or replacements 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 application.

Claims

1. A stirring mechanism of an electroplating apparatus, characterized by: The stirring mechanism comprises a shielding area and a stirring area, the shielding area is used to weaken the flow field of the area; the stirring area comprises a plurality of first paddles arranged in parallel; wherein, In the wafer electroplating process, when the wafer gap is located in the shielding area, the rotation speed of the wafer is a first rotation speed, when the wafer gap is located in the stirring area, the rotation speed of the wafer is a second rotation speed, 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 gap in the shielding area.

2. The stirring mechanism of claim 1, wherein: The shielding area comprises 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, wherein: The shielding area comprises an area enclosed by a curved edge and the edge line of the stirring mechanism.

4. The stirring mechanism according to claim 2 or 3, wherein: 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 paddle.

5. The stirring mechanism of claim 1, wherein: A stirring unit is arranged in the shielding area, and the stirring force of the stirring unit is weaker than the stirring force of the first paddle.

6. The stirring mechanism of claim 5, wherein: The stirring unit comprises a plurality of second paddles arranged in parallel, and the stirring force of the second paddle is weaker than the stirring force of the first paddle.

7. The stirring mechanism of claim 6, wherein: The width of the upper end surface of the second paddle is greater than the width of the lower end surface of the second paddle.

8. The stirring mechanism of claim 7, wherein: The height of the upper end surface of the second paddle is higher than or equal to the height of the upper end surface of the first paddle.

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

10. The stirring mechanism of claim 9, wherein: 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 apparatus for electroplating on the surface of a wafer, characterized in that: The electroplating equipment comprises the stirring mechanism according to any one of claims 1-10, and the electroplating equipment is configured to: in the electroplating process, control the stirring mechanism to move parallel to the wafer, and stir the electroplating solution.

12. The electroplating equipment according to claim 11, wherein: The electroplating equipment further comprises a rotatable wafer holding device, the wafer holding device has a clamp for fixing the wafer, and the relative position of the wafer gap and the clamp is fixed.

13. A method of electroplating, characterized by, Comprise: In the electroplating equipment, a stirring mechanism comprising a shielding area and a stirring area is arranged, wherein the shielding area is used to weaken the flow field of the area, and the stirring area comprises a plurality of first paddles arranged in parallel; The electroplating equipment is used to electroplate 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 gap is located in the shielding area, the rotation speed of the wafer is a first rotation speed, when the wafer gap is located in the stirring area, the rotation speed of the wafer is a second rotation speed, 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 gap in the shielding area.

14. The electroplating method according to claim 13, wherein: In the electroplating equipment, a rotatable wafer holding device is arranged, and the rotation speed of the wafer is controlled by adjusting the rotation speed of the wafer holding device.

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