Wafer plating apparatus with independent anode and cathode

Abstract

The application discloses a wafer electroplating device with independent anode and cathode, which comprises an electroplating bath containing electroplating solution, an electroplating groove with an electroplating cavity, a separation assembly and an anode assembly, wherein the electroplating groove is open at the top; the separation assembly is inserted into the electroplating cavity and separates the electroplating cavity into an anode cavity and a cathode cavity which are sealed from the circumference, and the separation assembly comprises an ion membrane, a first grid plate and a second grid plate arranged on opposite sides of the ion membrane, wherein a plurality of first grid holes and a plurality of second grid holes are formed on the first grid plate and the second grid plate; the anode assembly comprises a circulating pipeline connected with the anode cavity and a conductive column inserted into the anode cavity and connected with the positive pole of a power supply. The application can maintain the content of metal ions in the whole anode cavity, thereby ensuring stable supply of metal ions in the whole electroplating process and effectively improving the electroplating quality; meanwhile, the consumption of anode plates can be saved, and the production cost can be effectively reduced.

Description

Technical Field

[0001] This invention belongs to the field of semiconductor processing technology, and specifically relates to a wafer electroplating device with independent anode and cathode. Background Technology

[0002] A wafer is a silicon wafer used to fabricate silicon semiconductor circuits; its raw material is silicon. High-purity polycrystalline silicon is dissolved, doped with silicon crystal seed crystals, and then slowly pulled out to form a cylindrical single-crystal silicon wafer. After grinding, polishing, and slicing, the silicon crystal ingot forms a silicon wafer. Further, a conductive metal layer is electroplated onto the wafer, and the conductive metal layer is processed to create conductive circuitry.

[0003] Currently, wafer electroplating equipment generally includes an electroplating tank for holding the electroplating solution, a wafer carrier for fixing the wafer, an anode plate, and electrical components. The wafer carrier and the anode plate are respectively inserted into the electroplating solution in the electroplating tank, and the electrical components are respectively connected to the wafer and the anode plate, so that the wafer in the electroplating tank is the cathode and the anode plate is the positive electrode, thereby generating an electrolytic reaction in the electroplating tank. In this way, the metal ions in the electroplating solution can gradually adhere to the wafer surface to form an electroplating layer as the electrolytic reaction proceeds.

[0004] However, in actual electroplating processes, existing electroplating equipment has the following drawbacks:

[0005] 1. The anode plate used will gradually become thinner as the electrolysis reaction proceeds. This can easily lead to an unstable supply of metal ions, resulting in poor coating quality in the later stages.

[0006] 2. The anode plates need to be replaced before they are completely used up, resulting in waste and high costs. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a brand-new wafer electroplating equipment with independent anode and cathode.

[0008] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0009] A wafer electroplating apparatus with independent anode and cathode includes an electroplating tank forming an electroplating cavity, a partition assembly, and an anode assembly. The electroplating tank has an open opening from the top. The partition assembly is inserted into the electroplating cavity and divides the electroplating cavity into a circumferentially sealed anode cavity and a cathode cavity connected to the open opening. The partition assembly includes an ion membrane, a first grid plate and a second grid plate respectively disposed on opposite sides of the ion membrane. The first grid plate and the second grid plate have corresponding first grid holes and multiple second grid holes, and the multiple first grid holes, the ion membrane, and the multiple second grid holes form a metal ion channel. A wafer carrier loaded with wafers passes through the open opening from top to bottom and is inserted into the cathode cavity. The wafer carrier is connected to the negative terminal of the power supply. The anode assembly includes a circulation pipe connected to the anode cavity and a conductive column inserted into the anode cavity and connected to the positive terminal of the power supply. A solution containing metal ions circulates in the circulation pipe and the anode cavity. The conductive column is immersed in the solution. Under the action of current, metal ions enter the cathode cavity from the anode cavity through the metal ion channel and are plated onto the wafer surface.

[0010] Preferably, the first grid plate and the second grid plate are fixedly connected, and the ion exchange membrane is pressed between the first grid plate and the second grid plate. This maintains a smooth ion exchange membrane surface, thereby improving the permeability of the corresponding metal ions.

[0011] Preferably, the first grid plate is located on the side of the ion membrane closer to the anode cavity, and the second grid plate is located on the side of the ion membrane closer to the cathode cavity. Both the first and second grid holes are elongated through-holes extending vertically, and multiple first and second grid holes are arranged side-by-side at intervals. The width of each first grid hole is greater than the width of each second grid hole. Here, the progressively narrowing grid holes prevent edge effects caused by uneven current distribution during metal ion diffusion.

[0012] Preferably, the first grid plate, the second grid plate, and the ion membrane are all circular, and their center lines coincide.

[0013] Preferably, the diameters of the first grid plate, the second grid plate, and the ion membrane are d1, d2, and d3, respectively, where d1 < d3 ≤ d2; and / or, the area of ​​the metal ion passage region formed by the first grid plate is s1, and the area of ​​the metal ion passage region formed by the second grid plate is s2, where s1 = s2. Here, the reasonable dimensional relationship between the first grid plate, the second grid plate, and the ion membrane effectively restricts the movement of metal ions, thereby improving the stability of the electroplating process.

[0014] Preferably, the electroplating chamber is a rectangular cavity, and there are two sets of partition components, which respectively form an anode cavity between the opposite side walls of the electroplating chamber, and a cathode cavity is located between the two sets of partition components. This is applicable to wafer carriers with wafers mounted on both sides, so as to perform electroplating of two wafers simultaneously.

[0015] Preferably, the electroplating tank includes a tank body with an open top and tank plates connected to opposite sides of the tank body, wherein an electroplating cavity is formed between the tank body and the two tank plates, and each tank plate is recessed inward to form an anode tank, and each set of partition components is sealed to the opening of the corresponding anode tank. This design is simple and easy to install and implement.

[0016] Specifically, the top of the anode tank protrudes upwards and the bottom protrudes downwards, and the circulation pipeline includes an inlet pipe formed on the tank plate and connected to the bottom of the anode tank, and an outlet pipe formed on the tank plate and connected to the top of the anode tank. Here, the protrusions at the top and bottom of the anode tank ensure the stability of the chemical solution entering and exiting the anode chamber.

[0017] Preferably, the anode assembly further includes an insoluble anode plate disposed within the anode cavity and connected to the conductive post. Here, the conductive post and the insoluble anode plate work together to uniformly distribute the conductive current within the anode cavity.

[0018] Specifically, the anode plate is made of platinum-titanium mesh, and the surface of the anode plate is spaced apart from the cavity wall of the anode chamber. This ensures that the anode plate can be completely immersed in the solution containing metal ions.

[0019] Due to the implementation of the above technical solutions, the present invention has the following advantages compared with the prior art:

[0020] Existing wafer electroplating equipment suffers from drawbacks such as unstable metal ion supply leading to poor plating results and high cost due to excessive anode plate consumption, as soluble anode plates are consumed. In contrast, the wafer electroplating equipment of this application uses a solution containing metal ions as the anode, and separates the anode and cathode chambers independently via an ion-exchange membrane. During electroplating, the solution maintains continuous circulation, and under the influence of current, metal ions in the anode chamber pass through the ion-exchange membrane into the cathode chamber and are deposited onto the wafer surface. Therefore, compared to existing technologies, this invention maintains the metal ion content throughout the anode chamber through the continuous circulation of the solution containing metal ions, ensuring a stable supply of metal ions throughout the electroplating process and effectively improving electroplating quality. Simultaneously, it saves on anode plate consumption, effectively reducing production costs. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the installation of the wafer and wafer carrier according to the present invention;

[0022] Figure 2This is a schematic diagram of the wafer electroplating equipment according to Embodiment 1 of the present invention (the electroplating solution tank is not shown);

[0023] Figure 3 for Figure 2 A schematic diagram of the decomposition process;

[0024] Figure 4 for Figure 3 Schematic diagram of the middle channel plate;

[0025] Figure 5 for Figure 4 A top-down view;

[0026] Figure 6 for Figure 5 Schematic diagram of the sectional view along the central AA direction;

[0027] Figure 7 for Figure 5 Schematic diagram of the BB-direction section;

[0028] Figure 8 for Figure 3 Exploded view of the middle separator component;

[0029] Figure 9 This is an exploded view of the wafer electroplating equipment of Embodiment 2 of the present invention (partially omitted);

[0030] Wherein: J represents the wafer carrier; Y represents the wafer;

[0031] 1. Electroplating tank; 10. Tank body; 11. Tank plate; 110. Anode tank; q. Electroplating chamber; q1. Anode chamber; q2. Cathode chamber; k1. Opening; k2. Liquid inlet;

[0032] 2. Separating component; 20. Ion exchange membrane; 21. First grid plate; 211. First grid hole; 22. Second grid plate; 222. Second grid hole;

[0033] 3. Anode assembly; 30. Circulation pipe; 300. Liquid inlet pipe; 301. Liquid outlet pipe; 31. Conductive column; 32. Anode plate. Detailed Implementation

[0034] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0035] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0036] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0037] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0038] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0039] It should be noted that when an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. When an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0040] Example 1

[0041] like Figures 1 to 8 As shown, in this embodiment, a wafer Y is fixed to the front and rear sides of the wafer carrier J. The wafer electroplating equipment in this embodiment is used to simultaneously perform copper plating on the surfaces to be electroplated on the wafer Y on the front and rear sides of the wafer carrier J. The wafer carrier J has a connection terminal for connecting to the power supply cathode. The wafer electroplating equipment in this embodiment includes an electroplating bath containing electroplating solution, an electroplating tank 1 forming an electroplating cavity q, a partition assembly 2, and an anode assembly 3.

[0042] Specifically, the electroplating tank can be any conventional structure used to supply electroplating solution into the electroplating chamber q.

[0043] In this example, the electroplating tank 1 has an open opening k1 at the top and an inlet k2 for the electroplating solution at the bottom. During electroplating, the electroplating tank 1 is inserted into the electroplating pool. The electroplating solution enters the electroplating chamber q from the electroplating pool through the inlet k2 and then overflows into the electroplating pool from the open opening k1 to form a circulation.

[0044] Specifically, the electroplating tank 1 includes a tank body 10 with an open opening k1 at the top and an inlet k2 at the bottom, and tank plates 11 connected to opposite sides of the tank body 10. A rectangular electroplating cavity q is formed between the tank body 10 and the two tank plates 11, and the inner wall of each tank plate 11 is recessed and forms an anode tank 110.

[0045] In this example, the partition component 2 is inserted into the electroplating chamber q and divides the electroplating chamber q into a circumferentially sealed anode chamber q1 and a cathode chamber q2 that are respectively connected to the open port k1 and the liquid inlet k2. Specifically, there are two sets of partition components 2, which are correspondingly and sealed to the opening of each anode groove 110. Each set of partition components 2 forms an anode chamber q1 between the corresponding anode groove 110, and the cathode chamber q2 is located between the two sets of partition components 2.

[0046] Each group of separating components 2 includes an ion membrane 20, a first grid plate 21 and a second grid plate 22 respectively disposed on opposite sides of the ion membrane 20, wherein the first grid plate 21 and the second grid plate 22 are respectively formed with a plurality of first grid holes 211 and a plurality of second grid holes 222, and the plurality of first grid holes 211, the ion membrane 20 and the plurality of second grid holes 222 constitute a metal ion channel.

[0047] Meanwhile, the first grid plate 21, the ion membrane 20, and the second grid plate 22 are sequentially connected and fixed by bolts, and the ion membrane 20 is pressed between the first grid plate 21 and the second grid plate 22. The first grid plate 21 is located on the side of the ion membrane 20 closer to the anode cavity q1, and the second grid plate 22 is located on the side of the ion membrane 20 closer to the cathode cavity q2. The first grid plate 21, the second grid plate 22, and the ion membrane 20 are all circular, and their center lines coincide. The diameters of the first grid plate 21, the second grid plate 22, and the ion membrane 20 are d1, d2, and d3, respectively, where d1 < d3 ≤ d2. The area of ​​the metal ion passage region formed by the first grid plate 21 is s1, and the area of ​​the metal ion passage region formed by the second grid plate 22 is s2, where s1 = s2.

[0048] Furthermore, both the first grille hole 211 and the second grille hole 222 are elongated through holes extending vertically, and multiple first grille holes 211 and multiple second grille holes 222 are arranged side by side at intervals, wherein the width of each first grille hole 211 is greater than the width of each second grille hole 222.

[0049] In this example, the anode assembly 3 includes a circulation pipe 30 connected to the anode cavity q1 and a conductive column 31 inserted into the anode cavity q1 and connected to the positive terminal of the power supply. During electroplating, the wafer carrier J, which carries the wafer Y, passes through the open opening k1 from top to bottom and is inserted into the cathode cavity q2. The wafer carrier J is connected to the negative terminal of the power supply. The solution containing metal ions circulates in the circulation pipe 30 and the anode cavity q1 through the operation of the external solution tank and the pump. The conductive column 31 is immersed in the solution. Under the action of the current, metal ions enter the cathode cavity q2 from the anode cavity q1 through the metal ion channel and are plated onto the surface of the wafer Y.

[0050] Specifically, the top of the anode tank 110 is convex upward and the bottom is convex downward, and the circulation pipe 30 includes an inlet pipe 300 formed on the tank plate 11 and connected to the bottom of the anode tank 110, and an outlet pipe 301 formed on the tank plate 11 and connected to the top of the anode tank 110.

[0051] In addition, this embodiment also includes a stirring plate that moves up and down in the cathode cavity q2 by a motor, which is a conventional technical means and will not be described in detail here.

[0052] In summary, this embodiment has the following advantages:

[0053] 1. By circulating the chemical solution containing metal ions, the content of metal ions in the entire anode cavity can be maintained, thereby ensuring a stable supply of metal ions throughout the electroplating process and effectively improving the electroplating quality; at the same time, it can save the consumption of anode plate additives and effectively reduce production costs.

[0054] 2. By using progressively narrower grid openings, the edge effect caused by uneven current distribution affecting the diffusion of metal ions during passage is avoided, thus preventing it from affecting the overall electric field distribution.

[0055] 3. By using the reasonable dimensional relationship between the first grid plate, the second grid plate, and the ion membrane, the movement of metal ions is effectively restricted, thereby improving the stability and consistency of the electroplating process;

[0056] 4. The protrusions at the top and bottom of the anode tank ensure the stability of the drug solution when entering and exiting the anode cavity.

[0057] Example 2

[0058] Combination Figure 9 As shown, the wafer electroplating equipment in this embodiment has a basically the same structure as that in Embodiment 1. The difference between the two is that:

[0059] The anode assembly 3 in this embodiment also includes an insoluble anode plate 32 disposed in the anode cavity q 1 and connected to the conductive post 31.

[0060] Specifically, the anode plate 32 is made of platinum titanium mesh, and the surface of the anode plate 32 is spaced apart from the cavity wall of the anode cavity q 1.

[0061] The present invention has been described in detail above, with the aim of enabling those skilled in the art to understand and implement the invention. However, this description should not be construed as limiting the scope of protection of the invention. All equivalent changes or modifications made in accordance with the spirit and essence of the invention should be included within the scope of protection of the invention.

Claims

1. A wafer electroplating apparatus with independent anode and cathode, characterized in that: It includes an electroplating tank containing electroplating solution, an electroplating bath forming an electroplating cavity, a partition assembly, and an anode assembly. The electroplating bath has an open opening from the top. The partition assembly is inserted into the electroplating cavity and divides the electroplating cavity into a circumferentially sealed anode cavity and a cathode cavity connected to the open opening. The partition assembly includes an ion membrane, a first grid plate and a second grid plate respectively disposed on opposite sides of the ion membrane. The first grid plate and the second grid plate are fixedly connected, and the ion membrane is pressed between the first grid plate and the second grid plate. The first grid plate and the second grid plate are respectively formed with a plurality of first grid holes and a plurality of second grid holes, and the plurality of first grid holes, the ion membrane and the plurality of second grid holes constitute a metal ion channel. The first grid plate is located on the side of the ion membrane closer to the anode cavity, and the second grid plate is located on the side of the ion membrane closer to the cathode cavity. The first grid holes and the second grid holes are both elongated through holes extending vertically, and the plurality of first grid holes and the plurality of second grid holes are arranged side by side at intervals. The width of each first grid hole is greater than the width of each second grid hole. A wafer carrier containing wafers passes through an open opening from top to bottom and is inserted into the cathode cavity. The wafer carrier is connected to the negative terminal of the power supply. The anode assembly includes a circulation pipe connected to the anode cavity, a conductive column inserted into the anode cavity and connected to the positive terminal of the power supply, and an insoluble anode plate disposed in the anode cavity and connected to the conductive column. A chemical solution containing metal ions circulates in the circulation pipe and the anode cavity. The conductive column is immersed in the chemical solution. Under the action of current, metal ions enter the cathode cavity from the anode cavity through the metal ion channel and are deposited onto the wafer surface.

2. The wafer electroplating equipment with independent anode and cathode as described in claim 1, characterized in that: The first grid plate, the second grid plate, and the ion membrane are all circular, and their center lines coincide.

3. The wafer electroplating equipment with independent anode and cathode as described in claim 2, characterized in that: The diameters of the first grid plate, the second grid plate, and the ion membrane are d1, d2, and d3 respectively, where d1 < d3 ≤ d2; and / or, the area of ​​the metal ion passage region formed by the first grid plate is s1, and the area of ​​the metal ion passage region formed by the second grid plate is s2, where s1 = s2.

4. The wafer electroplating equipment with independent anode and cathode as described in claim 1, characterized in that: The electroplating cavity is a rectangular cavity, and there are two sets of partition components, which respectively form the anode cavity between the opposite side walls of the electroplating cavity, and the cathode cavity is located between the two sets of partition components.

5. The wafer electroplating equipment with independent anode and cathode as described in claim 4, characterized in that: The electroplating tank includes a tank body with an open opening formed from the top, and tank plates respectively connected to opposite sides of the tank body. The electroplating cavity is formed between the tank body and the two tank plates. Each tank plate is recessed inward to form an anode tank, and each set of the partition components is sealed and connected to the opening of the corresponding anode tank.

6. The wafer electroplating equipment with independent anode and cathode as described in claim 5, characterized in that: The top of the anode tank is convex upward and the bottom is convex downward. The circulation pipe includes an inlet pipe formed on the tank plate and connected to the bottom of the anode tank, and an outlet pipe formed on the tank plate and connected to the top of the anode tank.

7. The wafer electroplating equipment with independent anode and cathode as described in claim 1, characterized in that: The anode plate is made of platinum titanium mesh, and the surface of the anode plate is spaced apart from the cavity wall of the anode cavity.

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