Electroplating device and electroplating method for improving electroplating uniformity

Abstract

The invention provides an electroplating device and an electroplating method for improving electroplating uniformity, the electroplating device comprises a laser distance measuring device, when an electroplating head clamps a wafer to enter an electroplating cavity and reaches the height of the laser distance measuring device, each laser distance measuring instrument contained in the laser distance measuring device measures the distance between the laser distance measuring instrument and the electroplating head; and the distance is fed back to the control device, if the distances displayed by the control device are equal, the electroplating head is made to move downwards to carry out the wafer electroplating process, and if the distances displayed by the control device are not equal, the electroplating head is moved until the distances fed back by the laser range finders are equal, and then the electroplating head is made to move downwards to carry out the wafer electroplating process. According to the invention, the wafer clamped by the electroplating head can be ensured to be concentric with the stirring device and the liquid inlet shunting device in the electroplating process, so that the electroplating liquid can be better deposited on the surface of the wafer, and the uniformity of an electroplating layer is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of electroplating, and in particular to an electroplating device for improving electroplating uniformity and an electroplating method using the electroplating device. Background Art

[0002] In recent years, due to the rapid increase in demand in the global consumer electronics market, semiconductor components produced by various semiconductor manufacturers have been developed in the direction of reducing package size, cost and weight, and on this basis, the function and performance of components have been enhanced. In order to make semiconductor power consumption lower and faster, and reduce RC delay, semiconductor metal interconnection is also developing rapidly. Compared with the PVD / CVD process for preparing metal film layers, the electroplating process has become the main preparation method for metal interconnection due to its low temperature and low cost advantages.

[0003] At present, the electroplating process is mainly used for metal interconnection and advanced packaging processes in wafer manufacturing and packaging. The metal copper interconnection process has become a key process in wafer manufacturing and advanced packaging technology. Its main advantages are lower resistivity and resistance to electromigration (since electrons will collide with ions in metal conductors during the conduction process, the momentum will be transferred to metal ions, thereby causing and promoting the slow movement of metal ions. This phenomenon is called electromigration. Electromigration has an important impact on the reliability of integrated circuits. This is because during the conduction process, electromigration will continue to accumulate and eventually produce scattered defects in metal wires. These defects continue to gather to form large voids, causing metal short circuits and directly affecting the performance of the circuit. Since the electromigration of copper is much smaller than that of aluminum materials, metallic copper has significant advantages. Therefore, metallic copper is widely used in the processes of advanced technology nodes), and can meet technical requirements such as smaller chip size, more powerful functions, and lower energy consumption.

[0004] In the metal copper interconnection process, the wafer with the diffusion barrier layer and the seed layer is immersed in a high-purity copper electroplating solution containing corresponding additives, and the already etched interconnection vias and trenches are filled defect-free by the electroplating process. The copper interconnection process runs through the entire chip manufacturing process. The copper electroplating solution used in the copper interconnection process has the excellent quality of low metal impurities, high purity and high cleanliness, which can meet the process requirements of Damascus copper interconnection, advanced packaging bump electroplating (Cu Pillar / Bump / RDL / UBM), silicon blind via / through hole (TSV) electroplating in integrated circuit manufacturing. Other metal electroplating includes electroplating tin, electroplating gold and other types, which have the characteristics of uniform coating, high current efficiency and strong plating solution stability. They are suitable for various processes such as electroplating in traditional integrated circuit packaging and advanced packaging, and require dense coating crystals and low impurity content.

[0005] For wafer electroplating, the uniformity of electroplating is an important indicator to measure the electroplating process capability. Among them, the distribution of electroplating current / electroplating solution flow field distribution / electroplating solution circulation method will affect the results of wafer electroplating. How to improve the uniformity of wafer electroplating has become a technical problem that needs to be solved urgently in this field. Summary of the invention

[0006] The purpose of the present invention is to improve the uniformity of the electroplated layer on the surface of a wafer during the wafer electroplating process.

[0007] According to a first aspect of the present invention, there is provided an electroplating device for improving electroplating uniformity, comprising a first driving device, an electroplating head, an electroplating tank, a circular stirring device, a second driving device, a laser distance measuring device and a control device;

[0008] The first driving device is connected to the electroplating head and can drive the electroplating head to move and rotate, and the electroplating head is used to clamp the wafer; the electroplating tank includes a circular electroplating chamber, the electroplating chamber contains electroplating liquid, and a liquid inlet diversion device is arranged at the center of the bottom circle of the electroplating tank; the stirring device is horizontally arranged in the electroplating chamber and the two are arranged concentrically; the second driving device is connected to the stirring device and can drive the stirring device to rotate;

[0009] The laser distance measuring device comprises a plurality of laser distance measuring devices evenly arranged on the wall of the electroplating chamber, the laser distance measuring devices are located above the stirring device and the plane where the laser distance measuring devices are located is parallel to the stirring device; the control device is connected to the laser distance measuring devices;

[0010] The plating head is made to clamp the wafer, and the first driving device is controlled to drive the plating head into the plating chamber. When the plating head enters the plating chamber and reaches the height of the laser rangefinder, each laser rangefinder measures the distance between it and the plating head, and feeds back the distance to the control device. If the distances displayed by the control device are equal, the first driving device continues to drive the plating head downward to perform the plating process on the wafer; if they are not equal, the first driving device moves the plating head horizontally until the distances fed back by each laser rangefinder are equal, and then the first driving device continues to drive the plating head downward to perform the plating process on the wafer.

[0011] In this technical solution, by adopting the above-mentioned structural design, it can ensure that the wafer clamped by the electroplating head is concentric with the stirring device and the liquid inlet diversion device during the electroplating process, thereby promoting the electroplating liquid to be better deposited on the wafer surface and improving the uniformity of the electroplating layer.

[0012] Preferably, the number of the laser rangefinders is 3, and the 3 laser rangefinders are equidistantly distributed on the cavity wall of the electroplating cavity at an angle of 120°.

[0013] In this technical solution, three laser rangefinders are used to judge whether the concentricity is good or not, so as to ensure the accuracy of the judgment. Of course, in other solutions of this application, the user can also choose other numbers of laser rangefinders according to actual needs, such as four laser rangefinders with 90° equal spacing, six laser rangefinders with 60° equal spacing, etc.

[0014] Preferably, the control device records the distance values ​​when each laser rangefinder is equidistant from the electroplating head, and the control device can calculate the electroplating head offset value according to the distance values ​​fed back by the laser rangefinder.

[0015] In the present technical solution, by adopting the above-mentioned structural design, the user can make targeted adjustments to the position of the plating head according to the offset value of the plating head fed back by the control device, thereby quickly completing the concentric setting.

[0016] Preferably, the stirring device comprises a circular stirring plate, and when the wafer is electroplated, the stirring plate rotates under the drive of the second driving device.

[0017] In this technical solution, by adopting the above-mentioned structural design, the rotational motion of the stirring plate accelerates the convection distribution between the effective chemical components of the electroplating solution on the wafer surface and eliminates hydrogen bubbles generated by overpotential as the stirring occurs, thereby greatly improving the uniformity of electroplating.

[0018] Preferably, the stirring plate is in an inverted disc shape, comprising a stirring zone that bulges upward and a bottom plate extending outward from the bottom of the stirring zone, wherein the stirring zone comprises an upper surface of the stirring zone and a side surface of the stirring zone; the stirring zone comprises a skeleton structure, and the skeleton structure comprises a plurality of intersecting transverse skeletons and longitudinal skeletons;

[0019] The stirring zone also includes a uniform flow port, which includes a middle uniform flow port and an edge uniform flow port. The middle uniform flow port is opened in the area enclosed by adjacent transverse frames and adjacent longitudinal frames, and the edge uniform flow ports are continuously opened on the edge of the upper surface of the stirring zone, the side of the stirring zone, and the position of the bottom plate surface close to its connection with the bottom of the stirring zone.

[0020] In the present technical solution, by adopting the above-mentioned structural design, when the electroplating solution is circulated and input upward from the lower center position of the electroplating chamber, the electroplating 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 electroplating solution more evenly distributed. At the same time, the edge uniform flow port is opened to the side and chassis of the stirring zone, so that the edge of the skeleton is openly distributed, thereby making the edge plating solution flow out in a controlled manner, reducing the thickness of the wafer edge coating, and reducing the wafer electroplating edge effect.

[0021] Preferably, a fin structure is provided on the transverse skeleton, and the shape of the fin structure is trapezoidal, and a nearly V-shaped opening is formed between adjacent fin structures; the density of the nearly V-shaped opening is greater when it is closer to the center of the upper surface of the stirring zone, and the density is lower when it is farther away from the center of the upper surface of the stirring zone.

[0022] In the present technical solution, by adopting the structural design described above, when the plating solution is circulated and input upward, the fin structure provided on the skeleton can drive the plating solution to move upward, so that the plating solution reaches the surface of the wafer. At the same time, the design also enables the plating solution to pass through the gaps formed between the fin structures and be distributed at different positions of the skeleton. Moreover, the gaps between the fin structures on the skeleton structure are V-shaped openings and are partitioned to adopt different density designs (more openings at the stirring center and fewer openings at the edge), thereby reducing the difference in the amount of plating solution at the center and edge of the wafer.

[0023] Preferably, the liquid inlet and flow diversion device comprises a liquid inlet portion and a flow diversion portion located above the liquid inlet portion, and the flow diversion portion has multiple rows of flow diversion holes evenly arranged along its extension direction.

[0024] In the present technical solution, by adopting the above-mentioned structural design, the electroplating solution can flow evenly to the cavity, and different positions of the electroplating cavity are evenly filled with the electroplating solution, so that the chemical components in the electroplating solution are evenly distributed on the surface of the wafer, reducing the concentration difference of the chemical components inside the electroplating cavity, thereby improving the uniformity of the metal deposition thickness of the entire wafer.

[0025] According to a second aspect of the present invention, there is provided an electroplating method for improving electroplating uniformity, using any of the electroplating devices for improving electroplating uniformity described above, comprising the following steps:

[0026] The wafer is loaded onto the electroplating head, and the electroplating liquid is fed into the electroplating chamber through the liquid inlet diversion device;

[0027] Control the first driving device to drive the electroplating head into the electroplating chamber. When the electroplating head enters the electroplating chamber and reaches the height of the laser rangefinder, each laser rangefinder measures the distance between it and the electroplating head and feeds back the distance to the control device.

[0028] If the distances displayed by the control device are equal, the first drive device continues to drive the electroplating head downward to perform the electroplating process on the wafer. If they are not equal, the first drive device moves the electroplating head horizontally until the distances fed back by each laser rangefinder are equal, and then the first drive device continues to drive the electroplating head downward to perform the electroplating process on the wafer.

[0029] In the present technical solution, by adopting the above-described design method, it is possible to ensure that the wafer clamped by the electroplating head is concentric with the stirring device and the liquid inlet diversion device during the electroplating process, thereby promoting better deposition of the electroplating liquid on the wafer surface, thereby improving the uniformity of the electroplating layer.

[0030] Preferably, during the electroplating process of the wafer, the first driving device is controlled to drive the wafer to rotate, and the second driving device is controlled to drive the stirring device to rotate.

[0031] In the present technical solution, by adopting the design method described above, during the wafer electroplating process, the plating solution is subjected to controlled physical stirring by rotating the stirring device, and the cathode liquid on the wafer surface is appropriately diverted and uniformly flowed. The plating solution moves along with the uniform flow of the stirring device, and the horizontal rotation of the wafer accelerates its diffusion into the grooves on the wafer surface, thereby reducing the concentration difference of the plating solution at the center and edge of the wafer.

[0032] Preferably, during the wafer electroplating process, the distance between the wafer and the stirring device is between 1 and 1.5 mm.

[0033] In the present technical solution, by adopting the above-mentioned structural design and adjusting the distance between the wafer and the stirring device, the thickness of the diffusion layer on the wafer surface can be controlled, so that the uniformity of the coating thickness on the wafer surface is improved.

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] 1. The present invention can ensure that the wafer clamped by the electroplating head is concentric with the stirring device and the liquid inlet diversion device during the electroplating process through the design of the laser distance measuring device, thereby promoting the electroplating solution to be better deposited on the wafer surface and improving the uniformity of the electroplating layer.

[0036] 2. In the wafer electroplating process, the present invention applies controlled physical stirring to the electroplating solution by implementing a unique stirring device, so as to appropriately divert and evenly flow the cathode solution on the wafer surface. The electroplating solution moves along with the even flow of this special stirring device, thereby improving the uniformity of the electroplating layer while ensuring the quality of electroplating. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] 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:

[0038] Figure 1 A schematic diagram of the structure of the electroplating device for improving electroplating uniformity according to Example 1;

[0039] Figure 2 Schematic diagram of the structure of the liquid inlet diversion device in Example 1;

[0040] Figure 3 The structure of the stirring device in Example 1 is shown in FIG. Figure 1 ;

[0041] Figure 4 is a side view of the stirring device in Example 1;

[0042] Figure 5 The structure of the stirring device in Example 1 is shown in FIG. Figure 2 ;

[0043] Figure 6 for Figure 5 A partial enlarged view of

[0044] Figure 7 It is a schematic diagram of the structure of the stirring device in Example 2;

[0045] Figure 8 for Figure 7 A partial enlarged view of

[0046] Fig. 9 for Figure 8 A partial enlarged view of

[0047] Fig.10 61 distribution points of wafer thickness test for 12-inch inspection calibration;

[0048] Fig.11 This is the non-uniformity result diagram of the 12-inch wafer when the plating head of the electroplating fixture is not concentric with the stirring device;

[0049] Fig.12 This is the non-uniformity result diagram of the 12-inch wafer when the plating head of the electroplating fixture is concentric with the stirring device;

[0050] Fig.13 The non-uniformity result diagram of the 12-inch wafer calibration test is shown when the plating head of the electroplating fixture is concentric with the stirring device and the distance between the wafer and the stirring device is 0.5mm;

[0051] Fig.14 When the plating head of the electroplating fixture is concentric with the stirring device and the distance between the wafer and the stirring device is 0.8mm, the non-uniformity result diagram of the 12-inch wafer calibration test;

[0052] Fig.15 When the plating head of the electroplating fixture is concentric with the stirring device and the distance between the wafer and the stirring device is 1.0 mm, the non-uniformity result diagram of the 12-inch wafer calibration is shown;

[0053] Fig.16 The non-uniformity result diagram of the 12-inch wafer calibration test when the plating head of the electroplating fixture is concentric with the stirring device and the distance between the wafer and the stirring device is 1.2mm;

[0054] Fig.17 The non-uniformity result diagram of the 12-inch wafer calibration test when the plating head of the electroplating fixture is concentric with the stirring device and the distance between the wafer and the stirring device is 1.5mm;

[0055] Fig.18 When the plating head of the electroplating fixture is concentric with the stirring device and the distance between the wafer and the stirring device is 1.8mm, the non-uniformity result diagram of the 12-inch wafer calibration test;

[0056] Fig.19 When the plating head of the electroplating fixture is concentric with the stirring device and the distance between the wafer and the stirring device is 2.0 mm, the non-uniformity result diagram of the 12-inch wafer is detected and calibrated.

[0057] The figure shows:

[0058] 100-Electroplating device for improving electroplating uniformity;

[0059] 1- first driving device;

[0060] 2-Electroplating head;

[0061] 3-Electroplating tank;

[0062] 4- stirring device;

[0063] 5- second driving device;

[0064] 7-Liquid inlet;

[0065] 8- electroplating chamber;

[0066] 9-Liquid inlet diversion device;

[0067] 10- Chassis;

[0068] 11- diversion part;

[0069] 20- stirring zone;

[0070] 21- upper surface of stirring zone;

[0071] 22- Side of stirring zone;

[0072] 30- skeleton structure;

[0073] 31- transverse skeleton;

[0074] 32-longitudinal skeleton;

[0075] 40-uniform flow port;

[0076] 41-Middle flow opening;

[0077] 42-edge flow uniformity port;

[0078] 50 - edge position;

[0079] 60-Fin structure;

[0080] 70-nearly V-shaped opening;

[0081] 80-Stirring plate DETAILED DESCRIPTION

[0082] 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.

[0083] 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.

[0084] 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.

[0085] First Embodiment

[0086] like Figure 1 As shown, this embodiment provides an electroplating device 100 for improving electroplating uniformity, the electroplating device 100 includes a first driving device 1, an electroplating head 2, an electroplating tank 3, a circular stirring device 4, a second driving device 5, a laser distance measuring device ( Figure 1 The first driving device 1 is a manipulator connected to the electroplating head 2, and the first driving device 1 can drive the electroplating head 2 to move, rotate, and swing. The electroplating head 2 is used to clamp the wafer. Driven by the first driving device 1, the electroplating head 2 drives the wafer to perform translation, rotation, swing, and other actions. For the structural design of the electroplating head in this embodiment, reference can be made to the invention patent with application number 202211717395.8 previously applied by the applicant.

[0087] The electroplating tank 3 includes a circular electroplating chamber 8, and a liquid inlet diversion device 9 is provided at the center of the bottom of the electroplating tank 3 ( Figure 1(not shown), the plating liquid enters the plating chamber 8 from the bottom center of the plating chamber 8 through the liquid inlet diversion device 9 to provide the environment required for wafer electroplating. The number of liquid inlet holes of the liquid inlet diversion device 9 can be selected by the user according to actual needs, and can be 1 or more. When the number of liquid inlet holes of the liquid inlet diversion device 9 is more than one, they are evenly distributed with the bottom of the plating tank 3 as the center.

[0088] like Figure 2 As shown, in order to make the plating liquid flow evenly to the plating chamber 8, the liquid inlet diversion device 9 is designed to include a liquid inlet portion 7 located at the bottom and a diversion portion 11 located above the liquid inlet portion 7. The liquid inlet portion 7 and the diversion portion 11 are cylindrical as a whole and the lateral dimension of the diversion portion 11 is larger than that of the liquid inlet portion 7. The diversion portion 11 is evenly provided with a plurality of rows of diversion holes along its circumferential side. When the plating liquid enters the diversion portion 11 from the liquid inlet portion 7, all or part of the plating liquid will flow evenly into the plating chamber 8 through the diversion holes provided on the diversion portion 11, thereby making different positions of the plating chamber 8 evenly filled with the plating liquid, and then the chemical components in the plating liquid are evenly distributed on the wafer surface, thereby reducing the concentration difference of the chemical components inside the plating chamber 8.

[0089] like Figure 1 As shown, the overall shape of the stirring device 4 is circular, which is horizontally arranged in the electroplating chamber 8 and the two are arranged concentrically, and the second driving device 5 is connected to the stirring device 4 and can drive the stirring device 4 to rotate in the electroplating chamber 8. The second driving device 5 can be a stepping motor, which can drive the stirring device 4 to rotate by gear transmission. For example, it can be that a transmission gear is sleeved on the transmission shaft of the stepping motor, and the stirring device 4 is connected to a rotating gear and arranged concentrically, and the transmission gear and the rotating gear are meshed. When the transmission shaft of the stepping motor starts to rotate, the transmission gear drives the stirring device 4 to rotate through the rotating gear. The rotation of the stirring device 4 can accelerate the convection distribution between the effective chemical components of the electroplating solution on the wafer surface and eliminate the hydrogen bubbles generated by the overpotential with the stirring, thereby greatly improving the uniformity of electroplating.

[0090] Furthermore, in this embodiment, the stirring device 4 mainly includes a stirring plate 80 in the shape of an inverted disk. Figure 4 As shown, the stirring plate 80 includes a stirring zone 20 that bulges upward and a bottom plate 10 that extends outward from the bottom of the stirring zone 20 . The stirring zone 20 includes a stirring zone upper surface 21 and a stirring zone side surface 22 .

[0091] like Figure 3 and Figure 5 As shown, the stirring zone 20 includes a skeleton structure 30, and the skeleton structure 30 includes a plurality of transverse skeletons 31 and a plurality of longitudinal skeletons 32 (Note: transverse and longitudinal are used as directional indications to describe the Figure 3The relative position relationship of the skeletons in two directions intersecting at a specific viewing angle is based on the convenience of description. When the viewing angle changes, such as Figure 3 The normal view is switched to Figure 5 Even if the directional indication is changed accordingly, the lateral frames 31 and longitudinal frames 32 are still correspondingly called. Multiple lateral frames 31 are arranged in parallel, and multiple longitudinal frames 32 are also arranged in parallel. The lateral frames 31 and longitudinal frames 32 are perpendicularly intersected. In this embodiment, the number of longitudinal frames 32 is 4, and the number of lateral frames 31 is relatively large.

[0092] like Figure 6 As shown, a fin structure 60 is provided on the transverse skeleton 31, and the fin structure 60 is a trapezoid and has the same height. The side inclination angles of the fin structure 60 are the same, and the intervals between adjacent fin structures 60 are the same, thereby forming a nearly V-shaped opening 70 with the same opening angle between adjacent fin structures 60. The design of the nearly V-shaped opening 70 enables the plating solution to stay at different positions of the skeleton during the rotation of the stirring device 4, 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 with the stirring. In addition, the nearly V-shaped openings 70 are densely distributed and unevenly distributed on the upper surface 21 of the stirring zone. 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 amount difference of the plating solution in the middle and edge of the wafer, 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, reducing the concentration difference between the center of the wafer and the edge of the wafer.

[0093] Furthermore, the stirring zone 20 also includes a flow-uniform opening 40, which includes a middle flow-uniform opening 41 and an edge flow-uniform opening 42. The middle flow-uniform opening 41 is opened in the area enclosed by the adjacent transverse skeleton 31 and the adjacent longitudinal skeleton 32, and the edge flow-uniform opening 42 is continuously opened at the edge of the upper surface 21 of the stirring zone, the side surface 22 of the stirring zone, and the surface of the chassis 10 near the position where it is connected to the bottom of the stirring zone. In this embodiment, the opening widths of the middle flow-uniform opening 41 and the edge flow-uniform opening 42 are uniform and consistent, thereby making the distribution of the plating solution more uniform, and the design also makes the edge of the skeleton 100% open, so that the edge plating solution can flow out in a controlled manner, reducing the thickness of the wafer edge coating and reducing the wafer electroplating edge effect.

[0094] When in use, the stirring plate 80 is installed in the electroplating chamber 8. During electroplating, it is in a rotating state driven by the second driving device 5 directly or indirectly connected thereto. When the plating liquid is circulated upward from the center position of the lower circle of the electroplating chamber 8, the plating liquid will be broken up by the transverse skeleton 31 and the longitudinal skeleton 32 of the stirring zone 20 and pass through the uniform flow port 40, thereby making the plating liquid more evenly distributed; at the same time, the fin structure 60 arranged on the transverse skeleton 31 can drive the plating liquid to move upward so that the plating liquid reaches the surface of the wafer. At the same time, the gap formed between the fin structures 60 also enables the plating liquid to be distributed at different positions of the skeleton, thereby accelerating the convection distribution between the effective chemical components of the plating liquid on the wafer surface.

[0095] In general, the present embodiment applies controlled physical stirring to the plating liquid during the wafer electroplating process through the design of the stirring plate 80, and performs appropriate diversion and uniform flow on the cathode liquid on the wafer surface. The plating liquid moves uniformly along with the stirring plate 80, which accelerates the diffusion into the grooves on the wafer surface, reduces the concentration difference of the plating liquid at the center and edge of the wafer, and achieves uniform thickness of the electroplated film everywhere on the entire wafer.

[0096] In order to ensure that the wafer clamped by the electroplating head 2 is concentric with the stirring device 4 and the liquid inlet diversion device 9 during the electroplating process, thereby promoting the electroplating liquid to be better deposited on the wafer surface, thereby improving the uniformity of the electroplating coating, the present embodiment further adopts the following design: the laser ranging device includes three laser rangefinders uniformly arranged at 120° intervals on the wall of the electroplating chamber 8, the laser rangefinder is located above the stirring device 4 and the plane where the laser rangefinder is located is parallel to the stirring device 4, and the control device is connected to the laser ranging device.

[0097] When in use, first, make the plating head 2 clamp the wafer, and control the first driving device 1 to drive the plating head 2 into the plating chamber 8. When the plating head 2 enters the plating chamber 8 and reaches the height of the laser rangefinder, each laser rangefinder measures the distance between it and the plating head 2, and feeds back the distance to the control device. If the distance displayed by the control device is equal, it indicates that the wafer is concentric with the plating chamber 8. As mentioned above, the liquid inlet diversion device 9 is arranged at the center position of the bottom of the plating tank 3 (that is, it is also located at the bottom center position of the plating chamber 8), and the stirring device 4 is horizontally arranged in the plating chamber 8. At this time, the first driving device 1 continues to drive the plating head 2 downward to perform the wafer electroplating process. The wafer, the stirring device 4 and the liquid inlet diversion device 9 are concentric.

[0098] If the distances measured by each laser rangefinder and the electroplating head 2 are not equal, since the control device records the distance values ​​when each laser rangefinder is equidistant from the electroplating head 2, the control device can calculate the offset value of the electroplating head 2 based on the distance values ​​fed back by the laser rangefinders. Based on the offset value, the first drive device 1 moves the electroplating head horizontally until the distances fed back by each laser rangefinder are equal, and then the first drive device 1 continues to drive the electroplating head 2 downward to perform the electroplating process on the wafer. At this time, the wafer, the stirring device 4 and the liquid inlet diversion device 9 are concentric.

[0099] In the electroplating process of the wafer, the distance between the wafer and the stirring device 4 is set between 1 and 1.5 mm, and the second driving device 5 drives the stirring plate 80 of the stirring device 4 to be in a rotating state, and the first driving device 1 drives the wafer to be in a rotating state, thereby further accelerating the convection distribution between the effective chemical components of the electroplating solution on the wafer surface and improving the uniformity of electroplating.

[0100] In this embodiment, a laser distance measuring device is used for full closed-loop control, that is, whether the manipulator is in place is not determined by the software setting in advance, nor by the encoder of each axis motor, but by the actual value fed back by the final laser distance measuring device. The difference between these values ​​and the required control value is used as a feedback signal to drive and adjust the rotation angle of each axis motor of the manipulator, resulting in this control being a full closed loop (rather than an open loop or a semi-closed loop). From the perspective of kinematics, it is known that the error value at the end of the manipulator can be reversed to the electrode rotation angle that needs to be adjusted for each axis through the structural parameters of the manipulator.

[0101] Example 2

[0102] This embodiment also provides an electroplating device 100 for improving electroplating uniformity, and its structure is basically the same as that of the first embodiment, except that the structural design of the stirring device 4 is slightly different. The main difference of the stirring device 4 is the different degree of edge opening of the frame structure. In the first embodiment, the opening width of the edge flow equalization port 42 is uniform and consistent, so that the frame edge is 100% open. In this embodiment, as shown in FIG. Figure 7 and Figure 8 As shown, the opening width of the edge position 50 of the edge uniform flow opening 42 is smaller than the opening width of the non-edge position, so that the skeleton edge does not present a 100% open distribution, but presents an 80% to 90% open distribution.

[0103] Example 3

[0104] This embodiment provides an electroplating method for improving electroplating uniformity, using the electroplating device for improving electroplating uniformity described in any one of Embodiment 1 or Embodiment 2, comprising the following steps:

[0105] The wafer is loaded onto the electroplating head 2, and the electroplating liquid is fed into the electroplating chamber 8 through the liquid inlet diversion device 9;

[0106] Control the first driving device 1 to drive the electroplating head 2 to enter the electroplating chamber 8. When the electroplating head 2 enters the electroplating chamber 8 and reaches the height of the laser rangefinder, each laser rangefinder measures the distance between it and the electroplating head 2 and feeds the distance back to the control device.

[0107] If the distances displayed by the control device are equal, the first driving device 1 continues to drive the electroplating head 2 downward to perform the electroplating process on the wafer; if they are not equal, the first driving device 1 moves the electroplating head 2 horizontally until the distances fed back by the laser rangefinders are equal, and then the first driving device 1 continues to drive the electroplating head downward to perform the electroplating process on the wafer;

[0108] During the electroplating process of the wafer, the first driving device 1 is controlled to drive the wafer to rotate, and the second driving device 5 is controlled to drive the stirring device 4 to rotate.

[0109] In this embodiment, by adopting the above-mentioned step designs, it can be ensured that the wafer clamped by the electroplating head 2 is concentric with the stirring device 4 and the liquid inlet diversion device 9 during the electroplating process, thereby promoting the electroplating liquid to be better deposited on the wafer surface, thereby improving the uniformity of the electroplating layer; at the same time, during the wafer electroplating process, the stirring device 4 is rotated to apply controlled physical stirring to the plating solution, and the cathode inlet on the wafer surface is properly diverted and uniformly flowed. The plating solution moves uniformly with the stirring device 4, and with the horizontal rotation of the wafer, it will accelerate its diffusion into the grooves on the wafer surface, reducing the concentration difference of the plating solution at the center and edge of the wafer.

[0110] The following is a description of the technical effects achieved by the present invention through the above structural design and the above method through some test examples:

[0111] Test Example 1:

[0112] For 12-inch wafers, under suitable process conditions, one group adopted the electroplating method for improving electroplating uniformity described in Example 3, so that the plating head fixture and the stirring device were completely concentric during the wafer electroplating process, while the other group did not adopt the method described in Example 3, and there was a situation where the plating head fixture and the stirring device were not concentric during the wafer electroplating process.

[0113] by Fig.10 The 61 points shown are used as thickness test points to test the wafer electroplating non-uniformity (unless otherwise specified in the following text, the wafer electroplating non-uniformity is measured as Fig.10 The 61 points shown are used as thickness test points). Fig.11 The figure shows the non-uniformity results measured when the plating head fixture and the stirring device are not concentric during the wafer electroplating process. Fig.12The uniformity results measured by concentricity of the plating head fixture and the stirring device during wafer electroplating are shown.

[0114] Calculate the wafer non-uniformity and the results are as follows:

[0115] Electroplating fixture plating head and stirring device Different mind concentric Wafer non-uniformity 5.26％ 3.80％

[0116] according to Fig.11 and Fig.12 Based on the above results, we can draw the following conclusions:

[0117] 1. When the plating head device of the electroplating fixture is not concentric with the stirring device, the non-uniformity of the 12-inch wafer calibration test is 5.26%, and points 38 to 61 are the outer ring electroplating thickness, and the coating thickness fluctuates greatly.

[0118] 2. When the plating head device of the electroplating fixture is concentric with the stirring device, the non-uniformity of the 12-inch wafer is 3.80%, and points 38-61 are the outer ring electroplating thickness, and the coating thickness fluctuates very little.

[0119] Test Example 2:

[0120] For 12-inch inspection and calibration wafers, by further optimizing the distance between the plating head and the stirring device of the electroplating fixture, the wafer thickness non-uniformity is achieved to be less than 3%, and the best non-uniformity is 2.06%.

[0121]

[0122] Fig.13 It shows that when the plating head of the electroplating fixture is concentric with the stirring device and the distance between the wafer and the stirring device is 0.5 mm, the non-uniformity of the 12-inch wafer is detected and calibrated, and the result is 6.99%.

[0123] Fig.14 It shows that when the plating head of the electroplating fixture is concentric with the stirring device and the distance between the wafer and the stirring device is 0.8 mm, the non-uniformity of the 12-inch wafer is detected and calibrated, and the result is 4.56%.

[0124] Fig.15 It shows that when the plating head of the electroplating fixture is concentric with the stirring device and the distance between the wafer and the stirring device is 1.0 mm, the non-uniformity of the 12-inch wafer is detected and calibrated, and the result is 3.80%.

[0125] Fig.16 It shows that when the plating head of the electroplating fixture is concentric with the stirring device and the distance between the wafer and the stirring device is 1.2 mm, the non-uniformity of the 12-inch wafer is detected and calibrated, and the result is 2.06%.

[0126] Fig.17It shows that when the plating head of the electroplating fixture is concentric with the stirring device and the distance between the wafer and the stirring device is 1.5 mm, the non-uniformity of the 12-inch wafer is detected and calibrated, and the result is 4.06%.

[0127] Fig.18 It shows that when the plating head of the electroplating fixture is concentric with the stirring device and the distance between the wafer and the stirring device is 1.8 mm, the non-uniformity of the 12-inch wafer is detected and calibrated, and the result is 4.13%.

[0128] Fig.19 It shows that when the plating head of the electroplating fixture is concentric with the stirring device and the distance between the wafer and the stirring device is 2.0 mm, the non-uniformity of the 12-inch wafer is detected and calibrated, and the result is 5.36%.

[0129] According to the above test results: when the distance between the plating fixture plating head and the stirring device is controlled so that the distance from the wafer to the stirring device is 1.2mm during electroplating, the coating thickness is 1um, and the optimal non-uniformity of the 12-inch wafer reaches 2.06%.

[0130] 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. An electroplating device for improving electroplating uniformity, characterized in that: It includes a first driving device, an electroplating head, an electroplating tank, a circular stirring device, a second driving device, a laser distance measuring device and a control device; The first driving device is connected to the electroplating head and can drive the electroplating head to move and rotate, and the electroplating head is used to clamp the wafer; the electroplating tank includes a circular electroplating chamber, the electroplating chamber contains electroplating liquid, and a liquid inlet diversion device is arranged at the center of the bottom circle of the electroplating tank; the stirring device is horizontally arranged in the electroplating chamber and the two are arranged concentrically; the second driving device is connected to the stirring device and can drive the stirring device to rotate; The laser distance measuring device comprises a plurality of laser distance measuring devices evenly arranged on the wall of the electroplating chamber, the laser distance measuring devices are located above the stirring device and the plane where the laser distance measuring devices are located is parallel to the stirring device; the control device is connected to the laser distance measuring devices; The plating head is made to clamp the wafer, and the first driving device is controlled to drive the plating head into the plating chamber. When the plating head enters the plating chamber and reaches the height of the laser rangefinder, each laser rangefinder measures the distance between it and the plating head, and feeds back the distance to the control device. If the distances displayed by the control device are equal, the first driving device continues to drive the plating head downward to perform the plating process on the wafer; if they are not equal, the first driving device moves the plating head horizontally until the distances fed back by each laser rangefinder are equal, and then the first driving device continues to drive the plating head downward to perform the plating process on the wafer.

2. The electroplating device for improving electroplating uniformity according to claim 1, characterized in that: The number of the laser rangefinders is 3, and the 3 laser rangefinders are distributed on the cavity wall of the electroplating cavity at an equal distance of 120°.

3. The electroplating device for improving electroplating uniformity according to claim 1, characterized in that: The control device records the distance values ​​when each laser rangefinder is equidistant from the electroplating head, and the control device can calculate the offset value of the electroplating head according to the distance values ​​fed back by the laser rangefinder.

4. The electroplating device for improving electroplating uniformity according to claim 1, characterized in that: The stirring device comprises a circular stirring plate. When the wafer is electroplated, the stirring plate rotates under the drive of the second driving device.

5. The electroplating device for improving electroplating uniformity according to claim 4, characterized in that: The stirring plate is in an inverted disc shape, comprising a stirring zone that bulges upward and a bottom plate that extends outward from the bottom of the stirring zone, wherein the stirring zone comprises an upper surface of the stirring zone and a side surface of the stirring zone; the stirring zone comprises a skeleton structure, and the skeleton structure comprises a plurality of intersecting transverse skeletons and longitudinal skeletons; The stirring zone also includes a uniform flow port, which includes a middle uniform flow port and an edge uniform flow port. The middle uniform flow port is opened in the area enclosed by adjacent transverse frames and adjacent longitudinal frames, and the edge uniform flow ports are continuously opened on the edge of the upper surface of the stirring zone, the side of the stirring zone, and the position of the bottom plate surface close to its connection with the bottom of the stirring zone.

6. The electroplating device for improving electroplating uniformity according to claim 5, characterized in that: The transverse skeleton is provided with a fin structure, which is trapezoidal in shape, and a nearly V-shaped opening is formed between adjacent fin structures; the density of the nearly V-shaped opening is greater at a position closer to the center of the upper surface of the stirring zone, and the density is lower at a position farther away from the center of the upper surface of the stirring zone.

7. The electroplating device for improving electroplating uniformity according to claim 1, characterized in that: The liquid inlet and flow diversion device comprises a liquid inlet portion and a flow diversion portion located above the liquid inlet portion, and a plurality of rows of flow diversion holes are evenly arranged on the flow diversion portion along its extension direction.

8. An electroplating method for improving electroplating uniformity, characterized in that: The electroplating device for improving electroplating uniformity according to any one of claims 1 to 7 comprises the following steps: The wafer is loaded onto the electroplating head, and the electroplating liquid is fed into the electroplating chamber through the liquid inlet diversion device; Control the first driving device to drive the electroplating head into the electroplating chamber. When the electroplating head enters the electroplating chamber and reaches the height of the laser rangefinder, each laser rangefinder measures the distance between it and the electroplating head and feeds back the distance to the control device. If the distances displayed by the control device are equal, the first drive device continues to drive the electroplating head downward to perform the electroplating process on the wafer. If they are not equal, the first drive device moves the electroplating head horizontally until the distances fed back by each laser rangefinder are equal, and then the first drive device continues to drive the electroplating head downward to perform the electroplating process on the wafer.

9. The electroplating method for improving electroplating uniformity according to claim 8, characterized in that: During the electroplating process of the wafer, the first driving device is controlled to drive the wafer to rotate, and the second driving device is controlled to drive the stirring device to rotate.

10. The electroplating method for improving electroplating uniformity according to claim 9, characterized in that: During the electroplating process of the wafer, the distance between the wafer and the stirring device is between 1 and 1.5 mm.

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