Stirring device for electroplating and electroplating bath

Abstract

The invention provides a stirring device for electroplating and an electroplating bath, the stirring device for electroplating comprises a stirring plate with a special skeleton structure design and an open pore design, the stirring plate is used for applying controlled physical stirring to electroplating liquid medicine, and cathode liquid medicine on the surface of a wafer is subjected to proper flow division and flow uniformization, so that the electroplating liquid medicine is uniformly stirred; electroplating liquid medicine does uniform flow movement along with the stirring plate, diffusion and mass transmission towards the through holes / blind holes are accelerated, and the concentration difference of the electroplating liquid in the center and the edge of the wafer is reduced, so that material exchange in the through holes / blind holes is accelerated, deposition of metal ions is promoted, and the thickness of electroplating films on all positions of the whole wafer is uniform and consistent; and the through hole / blind hole is filled with defect-free filling with higher filling efficiency.

Description

Technical Field

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

[0002] TSV silicon through-via technology is a key technology for the 3D structure of high-end chips. It can penetrate the silicon substrate to achieve vertical electrical interconnection within the silicon wafer and between different silicon wafers for homogeneous or heterogeneous integration. This technology is currently the only vertical electrical interconnection technology and is one of the key technologies for realizing 3D advanced packaging. TSV technology can vertically conduct between wafers and between chips, thereby realizing wafer stacking and chip stacking. Its purpose is to greatly improve chip performance. It is one of the important technologies to solve the failure of Moore's Law. TSV technology can enable multiple chips to be stacked vertically, while improving performance, greatly reducing the substrate space occupied by the chip and improving heat dissipation. Due to the requirements of TSV core technology, technologies such as deep silicon etching and high-end horizontal copper electroplating have gradually developed and matured, which is beneficial to the commercial development of TSV electroplating technology and equipment.

[0003] At present, in order to meet the above needs in the field of high-end chips, the 3D TSV horizontal copper interconnection electroplating packaging of chips is becoming more and more widely used. Metal copper interconnection is the basis for achieving all this. Electroplated copper TSV technology plays a pivotal role in 3D interconnection, which can maintain chip interconnection at a very small size, shorten the signal transmission path, reduce RC delay, and reduce signal transmission power consumption. The key to developing a defect-free TSV electroplating process is to accelerate the diffusion of metal ions, reduce concentration differences, improve uniformity and quality transmission, and produce copper deposition without voids, gaps and seams through the effect of different additive ratios in the solution, that is, accelerators, levelers, brighteners and wetting agents and their relative diffusion / adsorption characteristics, through specific stirring in the near-wafer area.

[0004] In order to achieve stirring of the electroplating solution near the wafer, some technicians in this field have proposed installing a stirring device on the electroplating cathode chamber of the electroplating equipment. During electroplating, the stirring device is in a rotating state, and the electroplating solution is stirred by the stirring device so that its various components are more evenly dispersed. When the electroplating head carries the wafer into the electroplating solution, the chemical components in the electroplating solution move rapidly under the stirring of the stirring device, thereby uniformizing the ion density and accelerating the diffusion. This allows the chemical and ion components of the plating solution to be distributed on the wafer surface faster and more effectively, reducing the concentration difference of the plating solution between the center and edge of the wafer.

[0005] At the wafer level, in order to achieve higher production efficiency, 12-inch large-size wafers are now the mainstream production direction. How to achieve a very high level of copper electroplating process on large-size wafers is to improve the diffusion, uniform distribution and deposition capabilities of the electroplating solution while ensuring the quality of electroplating. To this end, it is necessary to further optimize the structure of the stirring device in the electroplating chamber and further improve and enhance the stirring method. This is the focus of the TSV electroplating equipment industry's current focus on equipment and process reform and innovation. Summary of the invention

[0006] In view of the defects in the prior art, the purpose of the present invention is to provide a stirring device for electroplating, which includes a stirring plate with a special structural design, and uses the stirring plate to apply controlled physical stirring to the electroplating solution, so as to appropriately divert and evenly flow the cathode solution on the surface of the wafer. The electroplating solution moves evenly along with the stirring plate (and can also be superimposed with the mixing effect of the horizontal rotation of the wafer according to actual needs), which will accelerate the diffusion and mass transfer into the through hole / blind hole, reduce the concentration difference of the electroplating solution at the center and edge of the wafer, thereby accelerating the material exchange in the through hole / blind hole, promoting the deposition of metal ions, and achieving uniform thickness of the electroplated film at various locations on the entire wafer, and defect-free filling with higher filling efficiency in the through hole / blind hole. In addition, the present invention also provides an electroplating tank including the above-mentioned stirring device for electroplating.

[0007] In order to achieve the above-mentioned object of the invention, the present invention adopts the following technical solution:

[0008] A stirring device for electroplating, comprising a hat-shaped stirring plate, wherein the stirring plate comprises a raised circular stirring area and a bottom plate extending outward from the bottom of the stirring area;

[0009] The stirring zone includes an upper surface of the stirring zone and a side surface of the stirring zone, and a skeleton structure and a plurality of uniform flow ports are arranged on the upper surface of the stirring zone; the skeleton structure includes a plurality of vertically intersecting transverse skeletons and longitudinal skeletons, and a trapezoidal boss is arranged on the transverse skeleton, and a nearly V-shaped opening is formed between the oblique side surfaces of adjacent trapezoidal bosses;

[0010] The flow-uniform openings include a middle flow-uniform opening and a side flow-uniform opening. The middle flow-uniform opening is opened in the area enclosed by the adjacent transverse frames and the adjacent longitudinal frames. The side flow-uniform openings are opened in the area enclosed by the adjacent transverse frames, the longitudinal frames arranged near the circumferential edge of the upper surface of the stirring zone, and the circumferential edge of the upper surface of the stirring zone.

[0011] It also includes multiple edge overflow ports, one end of which is connected to one end of the edge uniform flow port close to the circumferential edge of the upper surface of the stirring zone, and the other end extends in sequence to the edge position of the upper surface of the stirring zone, the side of the stirring zone, and the bottom plate surface close to the position where it is connected to the bottom of the stirring zone to form a right-angle Z-shaped structure.

[0012] In actual use, the stirring device for electroplating provided by the technical solution is installed in the plating chamber of the electroplating equipment. During electroplating, it will be in a rotating state. When the plating solution is circulated upward from the lower center position of the plating chamber, the plating solution will be broken up by the transverse and longitudinal skeletons of the stirring zone and pass through the uniform flow port, thereby making the plating solution more evenly distributed; at the same time, with the design of the trapezoidal boss on the transverse skeleton, the plating solution will not be completely drained from the center to the edge due to the centrifugal force generated by the rotation of the skeleton, but will move upward along the trapezoidal boss to reach the surface of the wafer, and dispersed at different positions on the skeleton through the nearly V-shaped opening; in addition, the setting of the edge overflow port makes the edge of the stirring zone open, thereby enabling the plating solution to flow out in a controlled manner and reduce the thickness of the coating on the edge of the wafer. In general, the technical solution uses the above-mentioned design to evenly disperse the various components in the plating solution. When the plating head carries the wafer into the plating solution, the chemical components in the plating solution are accelerated under the action of the stirring device, which makes the ion density uniform and accelerates the diffusion. This makes the chemical and ion components of the plating solution distribute faster and more effectively on the wafer surface, reducing the concentration difference of the plating solution between the center and edge of the wafer.

[0013] Preferably, the area of ​​the skeleton structure accounts for 55% to 65% of the upper surface area of ​​the stirring zone, the distance between adjacent transverse skeletons is between 4 and 8 mm, the distance between adjacent longitudinal skeletons is between 40 and 80 mm, and the thickness of the transverse and longitudinal skeletons is between 2 and 6 mm.

[0014] In the present technical solution, by adopting the above-mentioned structural design, the density of the framework of the stirring device is improved, thereby further reducing the turbulence of the liquid surface of the electroplating solution, improving the flatness of the liquid surface, eliminating bubbles, and achieving uniform distribution of the components of the electroplating solution.

[0015] Preferably, the opening widths of the middle flow equalizing port and the edge flow equalizing port are between 4 and 8 mm, the opening width of the edge overflow port is between 2 and 4 mm, and the opening width of the edge overflow port is 80% to 90% of the opening width of the edge flow equalizing port.

[0016] In the technical solution, by adopting the above-mentioned structural design, the skeleton edge is 80% to 90% openly distributed, and the edge plating liquid can flow out in a controlled manner, thereby reducing the thickness of the wafer edge plating layer.

[0017] Preferably, the height of the trapezoidal bosses is between 1 and 3 mm; the density of the nearly V-shaped openings formed between the trapezoidal bosses is greater the closer to the center of the upper surface of the stirring zone, and is lower the farther away from the center of the upper surface of the stirring zone.

[0018] In this technical solution, by adopting the above-mentioned structural design, the amount difference of the plating solution in the middle and edge of the wafer is reduced, thereby making the material distribution in the plating solution diffusion layer from the middle position of the wafer to the edge of the wafer more uniform, and reducing the concentration difference between the center of the wafer and the edge of the wafer. It should be noted that the density of the near-V-shaped openings in this technical solution increases at a position close to the center of the upper surface of the stirring zone. This increase can be caused by the gap between adjacent near-V-shaped openings getting smaller and smaller as they get closer to the center of the upper surface of the stirring zone, or it can be caused by zoning the stirring zone in advance, the gap between the near-V-shaped openings in the zone is the same, but the gap between adjacent near-V-shaped opening zones gets smaller and smaller as they get closer to the center of the upper surface of the stirring zone.

[0019] An electroplating tank comprises an electroplating chamber and any one of the above-mentioned stirring devices for electroplating, wherein the stirring device for electroplating is horizontally arranged in the electroplating chamber.

[0020] Preferably, it also includes a driving device, which is connected to the stirring device for electroplating and can drive the stirring device for electroplating to rotate at a preset speed.

[0021] In this technical solution, by adopting the above-mentioned structural design, the user can select the rotation speed of the stirring device for electroplating according to actual needs to improve the thickness distribution of the metal deposition layer on the surface of the wafer, eliminate bubbles, and improve hole filling defects.

[0022] Preferably, the preset speed is 100-120 rpm.

[0023] In this technical solution, by adopting the above-mentioned design, the uniformity of the metal deposition thickness of the entire wafer can be further improved.

[0024] Preferably, a liquid inlet diversion device is provided at the bottom center of the electroplating chamber, and the liquid inlet diversion device includes a liquid inlet portion and a diversion portion located above the liquid inlet portion, and a plurality of rows of diversion holes are evenly provided on the diversion portion along its extension direction.

[0025] In the present technical solution, by using a liquid inlet diversion device, the electroplating solution can flow evenly to the cavity, and different positions of the electroplating cavity are evenly filled with the electroplating solution, so that the chemical components in the electroplating solution are evenly distributed on the surface of the wafer, reducing the concentration difference of the chemical components inside the electroplating cavity, thereby improving the uniformity of the metal deposition thickness of the entire wafer.

[0026] Preferably, the liquid inlet portion and the diverter portion are both cylindrical, and the transverse dimension of the diverter portion is larger than that of the liquid inlet portion.

[0027] In the technical solution, by adopting the above-mentioned structural design, the electroplating solution is smoothly diverted in the diversion part to avoid the generation of bubbles.

[0028] Preferably, the liquid inlet volume of the liquid inlet diversion device is 18 to 22 liters per minute.

[0029] In this technical solution, by adopting the above-mentioned design, the uniformity of the metal deposition thickness of the entire wafer can be further improved.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] 1. The stirring device for electroplating provided by the present invention comprises a stirring plate with a special structural design, which is used to apply controlled physical stirring to the electroplating solution, so as to appropriately divert and evenly flow the cathode solution on the surface of the wafer. The electroplating solution moves evenly along with the stirring plate, thereby accelerating its diffusion and mass transfer into the through hole / blind hole, reducing the concentration difference of the electroplating solution at the center and edge of the wafer, thereby accelerating the material exchange in the through hole / blind hole, promoting the deposition of metal ions, and achieving uniform thickness of the electroplated film at various locations on the entire wafer, and defect-free filling with higher filling efficiency in the through hole / blind hole.

[0032] 2. The electroplating tank provided by the present invention uses a liquid inlet diversion device to make the electroplating solution flow evenly to the cavity, and the electroplating cavity is evenly filled with the electroplating solution at different positions, so that the chemical components in the electroplating solution are evenly distributed on the surface of the wafer, reducing the concentration difference of the chemical components inside the electroplating cavity, thereby improving the uniformity of the metal deposition thickness of the entire wafer. This design is combined with the design of the stirring device for electroplating, and together they can achieve the improvement of the uniformity of the metal deposition thickness in the TSV through-hole / blind hole and the thickness of the coating on the wafer surface. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Other features, objects and advantages of the present invention will become more apparent from the detailed description of non-limiting embodiments made with reference to the following drawings:

[0034] Figure 1 This is a schematic diagram of the structure of the stirring device for electroplating according to Example 1 of the present invention;

[0035] Figure 2 is a cross-sectional view of a stirring plate in Example 1 of the present invention;

[0036] Figure 3 This is a schematic diagram of the structure of the stirring device for electroplating according to Example 1 of the present invention;

[0037] Figure 4 for Figure 3 A partial enlarged view of

[0038] Figure 5 for Figure 3 A partial enlarged view of

[0039] Figure 6 It is a structural schematic diagram of the liquid inlet diversion device;

[0040] Figure 7It is the wafer thickness test point map;

[0041] Figure 8 The wafer electroplating uniformity test results of Test Example 1;

[0042] Fig. 9 The wafer electroplating uniformity test results of Test Example 2;

[0043] Fig.10 This is the result of filling 10x100um TSV wafer blind vias in test case 3;

[0044] Fig.11 This is the result of filling the 12x108um TSV wafer blind via in test example 3;

[0045] Fig.12 This is the result of filling 5x20um TSV wafer blind vias in test example 3;

[0046] Fig.13 This is the result of filling the 12x120um TSV wafer blind via in test case 3;

[0047] Fig.14 This is the uniformity result of the 12x120um TSV wafer blind hole filling test in Test Example 4;

[0048] Fig.15 This is the X-ray analysis result of the 12x120um TSV wafer blind hole filling test in Test Example 4.

[0049] The figure shows:

[0050] 100- stirring device for electroplating;

[0051] 10- Chassis;

[0052] 20- stirring zone;

[0053] 21- upper surface of stirring zone;

[0054] 22- Side of stirring zone;

[0055] 30- skeleton structure;

[0056] 31- transverse skeleton;

[0057] 32-longitudinal skeleton;

[0058] 32a - left longitudinal skeleton;

[0059] 32b - right longitudinal skeleton;

[0060] 40-uniform flow port;

[0061] 41-Middle flow opening;

[0062] 42-edge flow uniformity port;

[0063] 50-edge overflow;

[0064] 60-trapezoidal boss;

[0065] 70-nearly V-shaped opening;

[0066] 80- stirring plate;

[0067] 200-liquid inlet diversion device;

[0068] 210-liquid inlet;

[0069] 220-Diversion Department DETAILED DESCRIPTION

[0070] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and shown in the drawings here can be arranged and designed in various different configurations.

[0071] Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the present application for which protection is sought, but merely represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0072] It should be noted that similar numbers and letters represent similar items in the following figures. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in the subsequent figures. In addition, all directional indications in this application (such as up, down, left, right, front, back, bottom...) are only used to explain the relative position relationship, movement, etc. between the components under a certain specific posture (as shown in the figures). If the specific posture changes, the directional indication will also change accordingly. Furthermore, the descriptions involving "first", "second", etc. in the application are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated.

[0073] Example 1

[0074] like Figures 1 to 5As shown, this embodiment provides a stirring device 100 for electroplating, which is used to be installed on the electroplating cathode chamber of the electroplating machine. After the plating solution circulates into the electroplating cathode chamber, the various components in the plating solution will be evenly dispersed on the surface of the chamber through the stirring of the stirring device 100. When the plating head carries the wafer into the plating solution, the chemical components in the plating solution accelerate the movement to make the ion density uniform and accelerate the diffusion, which makes the chemical and ion components of the plating solution distribute on the wafer surface faster and more effectively, reducing the concentration difference of the plating solution between the center and the edge of the wafer.

[0075] Specifically, Figure 1 As shown, the stirring device 100 includes a circular stirring plate 80, and the stirring plate 80 includes a bottom plate 10 and a circular stirring area 20 protruding from the bottom plate 10. Figure 2 As shown, the overall shape of the stirring plate 80 is approximately hat-shaped, wherein the chassis 10 forms the brim of the hat-shaped structure of the stirring plate 80, and the stirring zone 20 protrudes from the chassis 10 to form a cap of the hat-shaped structure of the stirring plate 80, and the stirring zone 20 includes a stirring zone upper surface 21 and a stirring zone side surface 22.

[0076] Combination Figure 3 and Figure 4 As shown, the stirring zone 20 includes a skeleton structure 30 arranged on the upper surface 21 of the stirring zone, a plurality of strip-shaped uniform flow ports 40 uniformly opened on the upper surface 21 of the stirring zone, and a plurality of edge overflow ports 50 opened on the edge of the stirring zone 20. Among them, the skeleton structure 30 includes a plurality of transverse skeletons 31 and a longitudinal skeleton 32, and the plurality of transverse skeletons 31 are arranged in parallel in the transverse direction, and the plurality of longitudinal skeletons 32 are arranged in parallel in the longitudinal direction, and the transverse skeletons 31 and the longitudinal skeletons 32 are perpendicularly intersected. In this embodiment, there are 4 longitudinal skeletons 32, and the number of transverse skeletons 31 is relatively large. Based on the convenience of expression, the two longitudinal skeletons 32 close to the circumferential edge of the upper surface 21 of the stirring zone are referred to as the left longitudinal skeleton 32a and the right longitudinal skeleton 32b (it should be noted that the transverse and longitudinal directions are used as directional indications. When the stirring plate 80 is at different viewing angles, the directional indications will also change accordingly, but based on the convenience of description, this patent generally refers to the structure pointed to by the reference numeral 31 as the transverse skeleton 31, and the structure pointed to by the reference numeral 32 as the longitudinal skeleton 32).

[0077] Furthermore, the strip-shaped uniform flow openings 40 arranged on the upper surface 21 of the stirring zone include a central uniform flow opening 41 and an edge uniform flow opening 42. The opening widths of these two types of uniform flow openings are the same, and the main difference lies in the different positions. Among them, each central uniform flow opening 41 is opened in the area enclosed by two adjacent transverse frames 31 and two adjacent longitudinal frames 32, while the edge uniform flow openings 42 are opened in the area enclosed by two adjacent transverse frames 31, the left / right longitudinal frames 32a / 32b and the circumferential edge of the upper surface 21 of the stirring zone.

[0078] As for the edge overflow 50, Figure 4 and Figure 5 As shown, one end of the edge flow outlet 42 is close to the circumferential edge of the upper surface 21 of the stirring zone ( Figure 4 The other end extends to the circumferential edge of the upper surface 21 of the stirring zone, then bends downward along the side surface 22 of the stirring zone and continues to extend to the connection position between the side surface 22 of the stirring zone and the chassis 10, and then further bends and extends forward a short distance along the surface of the chassis 10, thereby forming a right-angle Z-shape in space (Note: in this embodiment, the right-angle Z-shape also includes the concept of an approximate right-angle Z-shape), and the opening width of the edge overflow port 50 is smaller than the opening width of the edge uniform flow port 42. Further, as Figure 4 and Figure 5 As shown, a plurality of trapezoidal bosses 60 are provided on the transverse frame 31 along its length direction, and a nearly V-shaped opening 70 is formed between the oblique side surfaces of adjacent trapezoidal bosses 60 .

[0079] The working principle of this embodiment is as follows: the electroplating stirring device 100 provided in this embodiment is installed in the electroplating chamber of the electroplating machine. During electroplating, the stirring device 100 is in a rotating state. When the plating solution is circulated and input upward from the center position of the lower part of the plating chamber, the plating solution will be broken up by the transverse skeleton 31 and the longitudinal skeleton 32 and pass through the strip-shaped uniform flow port 40, thereby making the plating solution more evenly distributed; at the same time, in conjunction with the design of the trapezoidal boss 60 on the transverse skeleton 31, the plating solution will not be completely drained from the center to the edge due to the centrifugal force generated by the rotation of the skeleton, but will move upward along the trapezoidal boss 60 to reach the wafer surface, and dispersed at different positions on the skeleton through the nearly V-shaped opening 70, thereby accelerating the convection distribution between the effective chemical components of the plating solution on the wafer surface and eliminating the hydrogen bubbles generated by the overpotential as the stirring; in addition, the setting of the edge overflow port 50 makes the edge of the stirring zone 20 open, which can make the plating solution flow out in a controlled manner and reduce the thickness of the coating on the edge of the wafer.

[0080] Example 2

[0081] This embodiment provides a stirring device 100 for electroplating. The structure of the stirring device is substantially the same as that of the stirring device provided in Embodiment 1, except that the present embodiment has the following improvements:

[0082] In this embodiment, the area of ​​the skeleton structure 30 accounts for 55% to 65%, preferably 60%, of the area of ​​the upper surface 21 of the stirring zone, thereby ensuring uniform distribution of the electroplating solution; and the distance between adjacent transverse skeletons 31 is 4 to 8 mm, preferably 6 mm, the distance between adjacent longitudinal skeletons 32 is between 40 and 80 mm, and the thickness of the transverse skeletons 31 and the longitudinal skeletons 32 is between 2 and 6 mm, preferably 4.5 mm, thereby further reducing the turbulence of the electroplating solution surface, improving the flatness of the liquid surface, eliminating bubbles, and achieving uniform distribution of the components of the electroplating solution.

[0083] In addition, in this embodiment, the opening widths of the middle flow-distributing port 41 and the edge flow-distributing port 42 are between 4 and 8 mm, preferably 6 mm, and the opening width of the edge overflow port 50 is between 2 and 4 mm, preferably 3 mm. The opening width of the edge overflow port 50 is 80% to 90% of the opening width of the edge flow-distributing port 42, and preferably 85%, thereby making the skeleton edge 80% to 90% open distribution, so that the plating solution can flow out in a controlled manner, reducing the thickness of the wafer edge coating.

[0084] Furthermore, in this embodiment, the trapezoidal bosses 60 have the same height, which is between 1 and 3 mm, preferably 2 mm, and the side inclination angles of the trapezoidal bosses 60 are the same, and the intervals between adjacent trapezoidal bosses 60 are the same, thereby forming a nearly V-shaped opening 70 with the same opening angle.

[0085] In addition, the distribution of the nearly V-shaped openings 70 on the upper surface 21 of the stirring zone is not uniform. On the whole, the closer the upper surface 21 of the stirring zone is to its center, the greater the density of the nearly V-shaped openings 70, and the farther away from its center, the smaller the density of the nearly V-shaped openings 70, thereby reducing the difference in the amount of plating solution between the middle and edge of the wafer, thereby making the material distribution in the plating solution diffusion layer from the middle of the wafer to the edge of the wafer more uniform, reducing the concentration difference between the center of the wafer and the edge of the wafer.

[0086] In this embodiment, in order to obtain the technical effect of different distribution densities of the nearly V-shaped openings 70 as described above, the trapezoidal bosses 60 at different positions have different lengths, that is, the closer to the center of the stirring zone, the smaller the length of the trapezoidal boss 60, and the farther away from the center of the stirring zone, the longer the length of the trapezoidal boss 60. When the spacing between the trapezoidal bosses 60 is the same, the density of the nearly V-shaped openings 70 formed by them is greater the closer to the center of the upper surface 21 of the stirring zone, and the density of the nearly V-shaped openings 70 farther away from the center is smaller.

[0087] The stirring device 100 for electroplating provided in this embodiment accelerates the movement of each chemical component in the electroplating solution, promotes the uniformity of ion density and accelerates diffusion, and eliminates bubbles; the design of the horizontal and vertical skeletons in the stirring device 100 is used to level the flatness of the cathode liquid surface of the electroplating chamber, effectively ensuring that the concentration of each part of the wafer surface is consistent; the nearly V-shaped opening 70 on the horizontal skeleton 31 has a high density at the center of the stirring, and a low density at the edge, thereby reducing the amount difference of the electroplating solution in the middle and edge of the wafer. Through the combination of the above designs, it is effectively ensured that the concentration of the electroplating solution at each position on the wafer surface is consistent, the liquid level is consistent, the difference in concentration between the cavity electroplating solution and the wafer surface / wafer surface center to edge is minimized as much as possible, the chemical and ion components enter the through hole / blind hole faster and more effectively, and the concentration difference between the through hole / blind hole and the external electroplating solution is reduced, thereby increasing the metal deposition thickness in the hole and ensuring uniform electroplating at all locations on the wafer surface.

[0088] Example 3

[0089] The present embodiment provides an electroplating tank, comprising an electroplating chamber, a driving device, and an electroplating stirring device 100 as described in Embodiment 1 or Embodiment 2. The electroplating stirring device 100 is horizontally arranged in the electroplating chamber, and is connected to the driving device. The driving device drives the electroplating stirring device 100 to rotate in the electroplating chamber, and the rotation speed is preferably 80 to 120 rpm (more preferably 100 to 120 rpm), and the stirring direction is preferably clockwise. The user can select the rotation speed of the electroplating stirring device 100 according to actual needs to improve the thickness distribution of the metal deposition layer on the surface of the wafer, eliminate bubbles, and improve hole filling defects.

[0090] A liquid inlet diverter 200 is provided at the bottom center of the electroplating chamber. The liquid inlet diverter 200 includes a liquid inlet 210 at the bottom and a diverter 220 on the liquid inlet 210. The liquid inlet 210 and the diverter 220 are cylindrical as a whole, and the lateral dimension of the diverter 220 is larger than that of the liquid inlet 210. The diverter 220 is evenly provided with multiple rows of diverter holes along its circumferential side. When the electroplating liquid enters the diverter 220 from the liquid inlet 210, the electroplating liquid will flow evenly into the electroplating chamber through the diverter holes provided on the diverter 220. Preferably, the liquid inlet volume of the liquid inlet diverter 200 is 18 to 24 liters / minute, and more preferably, the liquid inlet volume is 18 to 22 liters / minute. The user can adjust the flow rate of the liquid inlet diversion device 200 through a circulating pump, so that the electroplating solution can be fully circulated and the chemical composition can be uniform, thereby accelerating the material exchange in the diffusion layer, and timely replenishing the ions consumed by metal deposition, increasing the metal deposition thickness in the through hole / blind hole, and improving the hole filling defects.

[0091] This embodiment further reduces the turbulence of the electroplating liquid surface, improves the flatness of the liquid surface, eliminates bubbles, and achieves uniform distribution of the components of the electroplating liquid by adopting a specific stirring device with a vertical and horizontal skeleton layout, controlling the percentage of the open area to the stirring plate 80 area, and improving the skeleton shape, combined with a rotary stirring method with speed control. At the same time, a liquid inlet diversion device 200 is used to make the electroplating liquid flow evenly to the cavity, and different positions of the electroplating cavity are evenly filled with the electroplating liquid, and then the chemical components in the electroplating liquid are evenly distributed on the surface of the wafer, reducing the concentration difference of the chemical components inside the electroplating cavity, thereby improving the uniformity of the metal deposition thickness of the entire wafer. Furthermore, this embodiment improves the filling of blind holes of different apertures by optimizing the flow rate / stirring speed. Using the above device, the result of uniform distribution of additives in the liquid is achieved, thereby obtaining completely defect-free blind hole filling and obtaining good wafer uniformity.

[0092] The following is a description of the technical effects achieved by the above structural design and the parameter selection of the flow rate and the speed of the stirring device through some test examples:

[0093] Test Example 1:

[0094] For three TSV 12-inch wafers, electroplating was completed by controlling the rotation speed of the electroplating stirring device to 80, 100, and 120 rpm, the stirring direction was clockwise, and the cathode liquid flow rate was 18 to 24 L / min. Figure 7 The 61 points shown are used as thickness test points to test the uniformity of wafer electroplating. The test results are as follows: Figure 8 As shown, the wafer non-uniformity is calculated and the results are as follows:

[0095] Stirring speed 80rpm 100rpm 120rpm Wafer non-uniformity 13.61％ 9.03％ 8.87％

[0096] From the above results, it can be seen that when the stirring speed is 100-120rpm and the liquid flow rate is 18-24L / min, the wafer non-uniformity is <10%.

[0097] Test Example 2:

[0098] For TSV 12-inch wafers, electroplating is completed when the rotation speed of the electroplating stirring device is controlled to be 100-120 rpm, the stirring direction is clockwise, and the cathode liquid flow rate is 18-22 L / min. Figure 7 The 61 points shown are used as thickness test points to test the uniformity of wafer electroplating. The test results are as follows: Fig. 9 As shown, the wafer non-uniformity is calculated, and the result is: the coating thickness is 2um, the thickness non-uniformity of the 12-inch wafer is less than 10%, and the best non-uniformity is 4.77%.

[0099] Since there are too many additives in the TSV solution, it will affect the copper thickness distribution on the surface of the non-patterned wafer. Therefore, the test of non-uniformity is supplementary, and the main thing is to look at the subsequent hole filling effect and the uniformity of the thickness distribution on the surface of the patterned wafer. The blind hole pattern will affect the copper thickness distribution on the wafer surface. Therefore, the following test case 3 and test case 4 experimental data are further provided. Specifically:

[0100] Test Example 3:

[0101] According to the rotation speed of the stirring device and the flow range of the liquid medicine determined in Test Example 2, the blind hole is filled:

[0102] First, TSV 10x100um blind hole filling is performed, and the filling results are as follows Fig.10 As shown in the figure, it can be found that the 10x100um TSV blind hole filling can be done without defects by using the above process, and the copper thickness on the wafer surface is less than about 5 microns.

[0103] Second, TSV 12x108um blind hole filling is performed, and the filling results are as follows Fig.11 As shown in the figure, it can be found that the 12x108um TSV blind hole filling can be done without defects by using the above process, and the copper thickness on the wafer surface is less than about 6 microns.

[0104] Third, fill the TSV 5x20um blind hole. The filling results are as follows: Fig.12 As shown in the figure, it can be found that the 5x20um TSV blind hole filling can be done without defects by using the above process, and the copper thickness on the wafer surface is about 1 micron.

[0105] Fourth, TSV 12x120um blind hole filling is performed, and the filling results are as follows Fig.13 As shown in the figure, it can be found that the 12x120um TSV blind hole filling can be done without defects by using the above process, and the copper thickness on the wafer surface is about 2.5 microns.

[0106] Test Example 4:

[0107] Fig.14 The figure shows the uniformity test results of TSV 12x120um blind via wafer filling. For pattern wafer filling, the surface copper thickness non-uniformity of the blind via area can reach 6.09%, and the surface copper thickness non-uniformity of the whole wafer is 9.41% (at the location with blind via patterns, most of the copper ions will form copper element deposition in the hole, so the surface copper thickness will be lower than the location without blind via patterns, such as Fig.14As shown, the middle square area is the area with blind hole patterns, and the surface copper thickness is low. The surrounding area is the area without patterns, and the surface copper thickness is high. Due to the uneven PVD sputtering seed layer at the edge of the wafer, the surface copper thickness will be too high. These factors will affect the uniformity of the surface copper thickness of the entire wafer). The relevant test results are as follows:

[0108] Max(um) 4.18 Min(um) 3.47 Ave(um) 3.75 NU% 9.41％ NU%(via area) 6.09％

[0109] Furthermore, if Fig.15 As shown, the filling results of the graphic wafer were tested. Specifically, an X-ray machine was used to check the blind hole filling effect, and no abnormal defects were found.

[0110] It can be seen from the experimental data reflected in the above test examples that by adopting the electroplating tank provided in this embodiment, through the cooperation of the electroplating stirring device and the liquid inlet diversion device, and by optimizing the process parameters, defect-free filling of TSV blind holes of different sizes can be achieved, and the wafer non-uniformity is <10%.

[0111] The above describes the specific embodiments of the present invention. Based on the above description, relevant personnel can make various changes and modifications without departing from the technical concept of the present invention.

Claims

1. A stirring device for electroplating, characterized in that: The stirring plate comprises a hat-shaped stirring plate, wherein the stirring plate comprises a raised circular stirring area and a bottom plate extending outward from the bottom of the stirring area; The stirring zone includes an upper surface of the stirring zone and a side surface of the stirring zone, and a skeleton structure and a plurality of uniform flow ports are arranged on the upper surface of the stirring zone; the skeleton structure includes a plurality of vertically intersecting transverse skeletons and longitudinal skeletons, and a trapezoidal boss is arranged on the transverse skeleton, and a nearly V-shaped opening is formed between the oblique side surfaces of adjacent trapezoidal bosses; The flow-uniform openings include a middle flow-uniform opening and a side flow-uniform opening. The middle flow-uniform opening is opened in the area enclosed by the adjacent transverse frames and the adjacent longitudinal frames. The side flow-uniform openings are opened in the area enclosed by the adjacent transverse frames, the longitudinal frames arranged near the circumferential edge of the upper surface of the stirring zone, and the circumferential edge of the upper surface of the stirring zone. It also includes multiple edge overflow ports, one end of which is connected to one end of the edge uniform flow port close to the circumferential edge of the upper surface of the stirring zone, and the other end extends in sequence to the edge position of the upper surface of the stirring zone, the side of the stirring zone, and the bottom plate surface close to the position where it is connected to the bottom of the stirring zone to form a right-angle Z-shaped structure.

2. The stirring device for electroplating according to claim 1, characterized in that: The area of ​​the skeleton structure accounts for 55% to 65% of the upper surface area of ​​the stirring zone, the distance between adjacent transverse skeletons is between 4 and 8 mm, the distance between adjacent longitudinal skeletons is between 40 and 80 mm, and the thickness of the transverse skeleton and the longitudinal skeleton is between 2 and 6 mm.

3. The stirring device for electroplating according to claim 1, characterized in that: The opening widths of the middle flow-uniform opening and the edge flow-uniform opening are between 4 and 8 mm, and the opening width of the edge overflow opening is between 2 and 4 mm; the opening width of the edge overflow opening is 80% to 90% of the opening width of the edge flow-uniform opening.

4. The stirring device for electroplating according to claim 1, characterized in that: The height of the trapezoidal bosses is between 1 and 3 mm; the density of the nearly V-shaped openings formed between the trapezoidal bosses is greater the closer to the center of the upper surface of the stirring zone, and is lower the farther away from the center of the upper surface of the stirring zone.

5. An electroplating tank, characterized in that: It comprises an electroplating chamber and the stirring device for electroplating as claimed in any one of claims 1 to 4, wherein the stirring device for electroplating is horizontally arranged in the electroplating chamber.

6. The electroplating tank according to claim 5, characterized in that: It also includes a driving device, which is connected to the stirring device for electroplating and can drive the stirring device for electroplating to rotate at a preset speed.

7. The electroplating tank according to claim 6, characterized in that: The preset speed is between 100 and 120 revolutions per minute.

8. The electroplating tank according to claim 5, characterized in that: A liquid inlet diversion device is arranged at the bottom center of the electroplating chamber, and the liquid inlet diversion device comprises a liquid inlet portion and a diversion portion located above the liquid inlet portion, and a plurality of rows of diversion holes are evenly arranged on the diversion portion along its extension direction.

9. The electroplating tank according to claim 8, characterized in that: The liquid inlet portion and the flow diversion portion are both cylindrical, and the transverse dimension of the flow diversion portion is larger than that of the liquid inlet portion.

10. The electroplating tank according to claim 8, characterized in that: The liquid inlet flow rate of the liquid inlet diversion device is 18 to 22 liters per minute.

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