Wafer electroplating device

Abstract

The utility model belongs to the technical field of semiconductors, and particularly relates to a wafer electroplating device. The wafer electroplating device comprises a power supply assembly and an electroplating container, the electroplating container is provided with an electroplating bath, a cathode ring, electroplating liquid contained in the electroplating bath, a wafer and an anode electrode, the wafer and the anode electrode are immersed in the electroplating liquid, the top of the side wall of the electroplating bath is connected with a support, the support is provided with an annular cavity, and the annular cavity is communicated with the cathode ring. The annular cavity communicates with the electroplating tank, the cathode ring is arranged in the annular cavity, a liquid outlet is formed in the side, away from the electroplating tank, of the support and communicates with the annular cavity, and the power source assembly is used for supplying power to the electroplating container. By using the wafer electroplating device in the technical scheme, the cathode ring does not need to be replaced or disassembled for cleaning, so that the maintenance cost of the device is greatly reduced, the maintenance process of the device is simplified, and the production efficiency is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of semiconductors, in particular to a wafer electroplating device. Background Art

[0002] In the production process of semiconductor integrated circuits or other semiconductor devices, it is necessary to make a variety of metal layers on the surface of the wafer to achieve the function of electrical interconnection. Electroplating is one of the key processes for making these metal layers. The electroplating process is to place the wafer in the electroplating solution, connect the wafer base to the negative pole of the power supply, and connect the anode electrode to the positive pole of the power supply. The metal ions in the plating solution are deposited on the wafer surface through the use of an electric field.

[0003] With the development of semiconductor technology, the thickness of wafers is getting thinner and thinner. However, this will lead to uneven thickness of the electroplated metal layer. In order to improve the utilization rate of the wafer, the contact point between the wafer base and the wafer is usually located at the outer edge of the wafer. Therefore, there is a voltage difference between the center and edge of the wafer. This causes the electroplating rate in the center area of ​​the wafer to be much lower than the electroplating rate in the edge area of ​​the wafer, making the coating thickness in the edge area of ​​the wafer greater than the coating thickness in the center area of ​​the wafer, thus affecting the uniformity of the process.

[0004] In the prior art, a cathode ring is provided on the periphery of the wafer to improve the uniformity of the metal layer thickness. However, with this method, metal ions will continue to accumulate on the cathode ring, which will lead to a decrease in the function of the cathode ring. Therefore, the cathode ring needs to be replaced regularly or disassembled, cleaned and reinstalled, which affects production efficiency and increases production costs.

[0005] Therefore, it is urgent to propose a wafer electroplating device to solve the above problems. Utility Model Content

[0006] The purpose of the utility model is to at least solve the problem that the cathode ring needs to be replaced regularly or disassembled, cleaned and reinstalled. This purpose is achieved through the following technical solutions:

[0007] The first aspect of the utility model proposes a wafer electroplating device, comprising: a power supply component and an electroplating container, wherein the electroplating container has an electroplating tank, a cathode ring, and a plating solution, a wafer and an anode electrode contained in the electroplating tank, wherein the wafer and the anode electrode are immersed in the electroplating solution, a bracket is connected to the top of the side wall of the electroplating tank, the bracket has an annular chamber, and the annular chamber is connected to the electroplating tank, the cathode ring is arranged in the annular chamber, and a liquid outlet is opened on the side of the bracket away from the electroplating tank, and the liquid outlet is connected to the annular chamber, and the power supply component is used to supply power to the electroplating container.

[0008] The wafer electroplating device in the technical solution sets a cathode ring on the outer ring of the wafer. During the electroplating process, a voltage is applied to the anode electrode and the wafer through the power supply assembly, and the anode electrode undergoes an oxidation reaction to form metal ions (such as copper ions, silver ions, etc.). The metal ions are reduced to metal atoms and deposited on the surface of the wafer to form a metal layer. At the same time, some metal ions near the edge of the wafer in the electroplating solution are attracted to the cathode ring, thereby ensuring that the electroplating rate in the middle area of ​​the wafer is consistent with the electroplating rate in the edge area, thereby making the thickness of the metal layer formed by the wafer electroplating more uniform. During the wafer electroplating process, a certain amount of metal ions accumulates on the cathode ring, and the wafer electroplating device provided by this embodiment can be used to strip the cathode ring. By connecting the cathode ring to the positive electrode of the power supply assembly and the anode electrode to the negative electrode of the power supply assembly, the metal ions fall off the cathode ring. By opening a liquid outlet on the bracket, the metal ions that fall off can be taken away during the process of the electroplating solution flowing out of the liquid outlet. After the cathode ring is stripped, it can be used again in the electroplating process of the wafer without replacing or disassembling the cathode ring for cleaning, which greatly reduces the maintenance cost of the device, simplifies the device maintenance process, and improves production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] By reading the detailed description of the preferred embodiment below, various other advantages and benefits will become clear to those of ordinary skill in the art. The accompanying drawings are only used for the purpose of illustrating the preferred embodiment and are not to be considered as limiting the present invention. Moreover, the same reference numerals are used throughout the accompanying drawings to represent the same components. In the accompanying drawings:

[0010] Figure 1 It is a schematic diagram of the wafer electroplating device provided by the utility model during the electroplating process;

[0011] Figure 2 It is a partial structural schematic diagram of the wafer electroplating device provided by the utility model;

[0012] Figure 3 yes Figure 2 A partial enlarged view of the middle A;

[0013] Figure 4 yes Figure 2 A partial enlarged view of point B in the middle;

[0014] Figure 5 It is a schematic diagram of the flow direction of the electroplating solution in the wafer electroplating device provided by the utility model.

[0015] In the figure:

[0016] 100, electroplating container; 101, electroplating tank; 102, liquid outlet channel; 103, liquid inlet; 200, wafer; 300, anode electrode; 400, cathode ring; 410, diaphragm; 500, bracket; 501, liquid outlet; 510, baffle; 520, protective plate; 530, bending plate; 600, wafer base; 700, virtual anode; 800, cationic membrane. DETAILED DESCRIPTION

[0017] The exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0018] It should be understood that the terms used herein are only for the purpose of describing specific example embodiments and are not intended to be limiting. Unless the context clearly indicates otherwise, the singular forms "one", "an" and "said" as used herein may also be meant to include plural forms. The terms "include", "comprise", "contain", and "have" are inclusive, and therefore specify the existence of stated features, steps, operations, elements and / or parts, but do not exclude the existence or addition of one or more other features, steps, operations, elements, parts, and / or combinations thereof. The method steps, processes, and operations described herein are not interpreted as necessarily requiring them to be performed in the specific order described or illustrated, unless the execution order is clearly indicated. It should also be understood that additional or alternative steps may be used.

[0019] Although the terms first, second, third, etc. can be used in the text to describe multiple elements, components, regions, layers and / or sections, these elements, components, regions, layers and / or sections should not be limited by these terms. These terms can only be used to distinguish an element, component, region, layer or section from another region, layer or section. Unless the context clearly indicates, terms such as "first", "second" and other numerical terms do not imply order or sequence when used in the text. Therefore, the first element, component, region, layer or section discussed below can be referred to as the second element, component, region, layer or section without departing from the teaching of the example embodiments.

[0020] For ease of description, spatial relative terms may be used herein to describe the relationship of one element or feature relative to another element or feature as shown in the figure, such as "inside", "outside", "inner side", "outer side", "below", "below", "above", "above", etc. Such spatial relative terms are intended to include different orientations of the device in use or operation in addition to the orientation depicted in the figure. For example, if the device in the figure is turned over, then the elements described as "below other elements or features" or "below other elements or features" will subsequently be oriented as "above other elements or features" or "above other elements or features". Therefore, the example term "below..." can include both upper and lower orientations. The device can be oriented otherwise (rotated 90 degrees or in other directions) and the spatial relative descriptors used in the text are interpreted accordingly.

[0021] See also Figure 1 and Figure 2 The present embodiment provides a wafer electroplating device, including: a power supply component and an electroplating container 100, the electroplating container 100 has an electroplating tank 101, a cathode ring 400, and a plating solution, a wafer 200 and an anode electrode 300 contained in the electroplating tank 101, the wafer 200 and the anode electrode 300 are immersed in the electroplating solution, the top of the side wall of the electroplating tank 101 is connected to a bracket 500, the bracket 500 has an annular chamber, the annular chamber is connected to the electroplating tank 101, the cathode ring 400 is arranged in the annular chamber, the bracket 500 is provided with a liquid outlet 501 on the side away from the electroplating tank 101, the liquid outlet 501 is connected to the annular chamber, and the power supply component is used to supply power to the electroplating container 100.

[0022] The above-mentioned wafer electroplating device is provided with a cathode ring 400 on the outer ring of the wafer 200. During the electroplating process, a voltage is applied to the anode electrode 300 and the wafer 200 through the power supply assembly, and the anode electrode 300 undergoes an oxidation reaction to form metal ions (such as copper ions, silver ions, etc.), and the metal ions are reduced to metal atoms and deposited to form a metal layer on the surface of the wafer 200. At the same time, some metal ions in the electroplating solution close to the edge of the wafer 200 are attracted to the cathode ring 400, thereby ensuring that the electroplating rate in the middle area of ​​the wafer 200 is consistent with the electroplating rate in the edge area, thereby making the thickness of the metal layer formed by electroplating of the wafer 200 more uniform. During the electroplating process of the wafer 200, a certain amount of metal ions accumulates on the cathode ring 400, and the wafer electroplating device provided by this embodiment can be used to strip the cathode ring 400. By connecting the cathode ring 400 to the positive pole of the power supply assembly and the anode electrode 300 to the negative pole of the power supply assembly, the metal ions fall off the cathode ring 400. By providing a liquid outlet 501 on the support 500, the detached metal ions can be taken away when the electroplating liquid flows out of the liquid outlet 501. After the cathode ring 400 is stripped, the electroplating process of the wafer 200 can be used again, and there is no need to replace or disassemble the cathode ring 400 for cleaning, which greatly reduces the maintenance cost of the device, simplifies the device maintenance process, and improves production efficiency.

[0023] Optionally, the plating solution can be selected according to the type of the metal layer. For example, when the metal layer is copper, the plating solution may include a copper sulfate solution; when the metal layer is silver, the plating solution may include a silver sulfate solution. In this embodiment, the anode electrode 300 is located at the bottom of the plating tank 101, and the wafer 200 is located at the top of the plating tank 101. Optionally, a wafer base 600 is provided at the top of the plating tank 101, and the wafer base 600 is used to place the wafer 200. During the electroplating process, the wafer base 600 is used to be electrically connected to the negative electrode of the power supply component, so as to apply voltage to the wafer 200. Further, the cathode ring 400 is located at the outer ring of the wafer base 600. Optionally, the wafer base 600 is in the shape of a ring tray, and the outer edge of the wafer 200 is supported on the wafer base 600.

[0024] Furthermore, the bracket 500 is provided with a baffle 510 at the top of the liquid outlet 501, and the outer edge of the baffle 510 is inclined toward the bottom direction of the electroplating tank 101. The baffle 510 can play a protective and guiding role to prevent the electroplating liquid from splashing or dispersing upwards and causing pollution. Since the baffle 510 is inclined downwards, the electroplating liquid splashed onto the baffle 510 can naturally drip downwards. Optionally, the baffle 510 is arranged along the circumference of the side wall of the electroplating tank 101, and its top view is annular.

[0025] Further, see Figure 2A film 410 is provided on the side of the cathode ring 400 facing the electroplating tank 101. The film 410 can block metal ions, thereby reducing the probability of metal ions being discharged into the electroplating tank 101 after the cathode ring 400 is stripped, and allowing the metal ions to be discharged out of the electroplating tank 101 as much as possible.

[0026] Optionally, continue to see Figure 2 , the edge of the baffle 510 away from the bracket 500 is connected to a protective plate 520, which extends to the bottom of the electroplating tank 101 and forms a flow channel with the outer side of the side wall of the electroplating tank 101, and the plating liquid can flow into the flow channel through the liquid outlet 501. The protective plate 520 shields the plating liquid and prevents the plating liquid from being overly exposed to the atmosphere and hardening. Optionally, by increasing the length of the protective plate 520, the time the plating liquid is exposed to the atmosphere can be minimized, thereby improving the anti-hardening effect. Optionally, see Figure 3 The inner side of the connection between the baffle plate 510 and the protection plate 520 is rounded to facilitate the flow of the electroplating solution and prevent the accumulation of metal copper ions there.

[0027] Optionally, in order to reduce the contact between the electroplating solution and the atmosphere, a bending plate 530 may be provided at the bottom edge of the protective plate 520, and the area of ​​the flow channel outlet may be reduced by the bending plate 530. Optionally, the bottom of the bending plate 530 is inclined toward the electroplating tank 101, so as to avoid the formation of a flow dead angle at the connection between the protective plate 520 and the bending plate 530. In other embodiments, the bending plate 530 may also extend in the horizontal direction. Optionally, see Figure 4 The inner side of the connection between the protection plate 520 and the bending plate 530 is processed with a rounded transition, so as to facilitate the flow of the electroplating solution and prevent the accumulation of metal ions there.

[0028] In some embodiments, the liquid outlet 501 includes a plurality of through holes arranged at intervals along the circumferential direction of the side wall of the electroplating tank 101. The number and size of the through holes are set according to the use requirements and are not specifically limited here. In other embodiments, the liquid outlet 501 can also be an annular opening arranged along the circumferential direction of the side wall of the electroplating tank 101. The liquid outlet 501 can be located at the top, middle or bottom of the outer wall of the bracket 500, as long as the electroplating solution can flow out.

[0029] See also Figure 5 In one embodiment, a liquid outlet channel 102 is provided in the electroplating container 100, the liquid outlet channel 102 and the electroplating tank 101 are separated by the side wall of the electroplating tank 101, the liquid outlet port 501 is connected to the liquid outlet channel 102, and the electroplating liquid can flow into the liquid outlet channel 102 through the liquid outlet port 501. With the above structure, the electroplating liquid after stripping can flow out of the electroplating tank 101 through the liquid outlet channel 102. Optionally, the liquid outlet channel 102 is connected to a collecting tank, and the electroplating liquid flowing out of the liquid outlet channel 102 can flow into the collecting tank.

[0030] Further, see Figure 5 The bottom of the electroplating container 100 is provided with a liquid inlet 103, which is connected to the electroplating tank 101, and the electroplating solution enters the electroplating tank 101 through the liquid inlet 103. The liquid inlet 103 is provided for introducing the electroplating solution.

[0031] Furthermore, the wafer electroplating device further includes a virtual anode 700, which is located in the electroplating tank 101 and between the wafer 200 and the anode electrode 300, and the unit area resistance of the virtual anode 700 in the central area is smaller than the unit area resistance in the edge area. By setting the unit area resistance of the virtual anode 700 in the central area to be smaller than the unit area resistance in the edge area, the sum of the resistance of the virtual anode 700 in the central area plus the resistance from the edge of the wafer 200 to the center of the wafer 200 can be close to the resistance of the virtual anode 700 in the edge area, so that the current density at the center of the wafer 200 is close to the current density at the edge of the wafer 200, and then the metal deposition speed at the center of the wafer 200 is close to the metal deposition speed at the edge of the wafer 200, which helps to make the thickness of the metal layer formed by electroplating at the center of the wafer 200 consistent with the thickness of the metal layer at the edge of the wafer 200, thereby improving the uniformity of the metal layer formed by electroplating. Optionally, the material of the virtual anode may be selected from materials having acid corrosion resistance, such as polyethylene, polypropylene, polyvinylidene fluoride, polytetrafluoroethylene and polysulfone.

[0032] Further, a cationic membrane 800 is provided in the electroplating tank 101, and the cationic membrane 800 is located between the wafer 200 and the anode electrode 300. The function of the cationic membrane 800 is to block the non-cations between the wafer 200 and the cationic membrane 800, to prevent the non-cations from moving to one end of the anode electrode 300, or even attaching to the anode electrode 300, and affecting the oxidation reaction of the metal ions. Among them, the non-cations can be additive ions that make the metal ions form a thin film more uniformly. Further, the cationic membrane 800 can be located between the virtual anode 700 and the anode electrode 300, thereby reserving more space for the non-cations.

[0033] Obviously, the above embodiments of the present invention are merely examples for the purpose of clearly illustrating the present invention, and are not intended to limit the implementation methods of the present invention. For those skilled in the art, various obvious changes, readjustments and substitutions can be made without departing from the scope of protection of the present invention. It is not necessary and impossible to list all implementation methods here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention shall be included in the scope of protection of the claims of the present invention.

Claims

1. A wafer electroplating device, characterized in that: include: A power supply component and an electroplating container (100), wherein the electroplating container (100) comprises an electroplating tank (101), a cathode ring (400), and an electroplating solution, a wafer (200), and an anode electrode (300) contained in the electroplating tank (101), wherein the wafer (200) and the anode electrode (300) are immersed in the electroplating solution, a bracket (500) is connected to the top of the side wall of the electroplating tank (101), and the bracket (500) comprises an annular chamber, which is communicated with the electroplating tank (101), and the cathode ring (400) is arranged in the annular chamber, and a liquid outlet (501) is provided on a side of the bracket (500) facing away from the electroplating tank (101), and the liquid outlet (501) is communicated with the annular chamber, and the power supply component is used to supply power to the electroplating container (100).

2. The wafer electroplating device according to claim 1, characterized in that: The support (500) is provided with a baffle (510) at the top of the liquid outlet (501), and the outer edge of the baffle (510) is inclined toward the bottom of the electroplating tank (101).

3. The wafer electroplating device according to claim 2, characterized in that: A protective plate (520) is provided at the bottom edge of the baffle (510), and the protective plate (520) extends toward the bottom of the electroplating tank (101) and forms a flow channel with the outer side of the side wall of the electroplating tank (101), and the electroplating liquid can flow into the flow channel through the liquid outlet (501).

4. The wafer electroplating device according to claim 3, characterized in that: A bending plate (530) is provided at the bottom edge of the protection plate (520), and the bottom of the bending plate (530) is inclined toward the direction of the electroplating tank (101).

5. The wafer electroplating device according to any one of claims 1 to 4, characterized in that: The liquid outlet (501) comprises a plurality of through holes arranged at intervals in the circumferential direction along the side wall of the electroplating tank (101).

6. The wafer electroplating device according to any one of claims 1 to 4, characterized in that: A liquid outlet channel (102) is provided in the electroplating container (100); the liquid outlet channel (102) and the electroplating tank (101) are separated by the side wall of the electroplating tank (101); the liquid outlet (501) and the liquid outlet channel (102) are connected; the electroplating liquid can flow into the liquid outlet channel (102) through the liquid outlet (501).

7. The wafer electroplating device according to any one of claims 1 to 4, characterized in that: The bottom of the electroplating container (100) is provided with a liquid inlet (103), the liquid inlet (103) is in communication with the electroplating tank (101), and the electroplating liquid enters the electroplating tank (101) through the liquid inlet (103).

8. The wafer electroplating device according to any one of claims 1 to 4, characterized in that: A wafer base (600) is arranged on the top of the electroplating tank (101), the cathode ring (400) is located on the outer ring of the wafer base (600), and the wafer base (600) is used to place the wafer (200) and is used to be electrically connected to the negative electrode of the power supply component.

9. The wafer electroplating device according to any one of claims 1 to 4, characterized in that: The wafer electroplating device further comprises a virtual anode (700), wherein the virtual anode (700) is located in the electroplating tank (101) and between the wafer (200) and the anode electrode (300), and the resistance per unit area of ​​the virtual anode (700) in the central region is smaller than the resistance per unit area in the edge region.

10. The wafer electroplating device according to any one of claims 1 to 4, characterized in that: A cationic membrane (800) is arranged in the electroplating tank (101), and the cationic membrane (800) is located between the wafer (200) and the anode electrode (300).

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