Electroplating ring, electroplating apparatus, and wafer cleaning method

Abstract

The application relates to the technical field of semiconductors, and discloses an electroplating ring, an electroplating device and a wafer cleaning method. The device comprises: an electroplating ring for placing a wafer; a positioning pin located on the electroplating ring and used for stabilizing the wafer; the positioning pin is divided into two parts: a base part connected with the electroplating ring and a contact part in contact with the wafer; wherein the contact part is designed as an elliptic cylindrical structure; and a cavity used for carrying out a wafer cleaning process. Through improvement of the contact part of the positioning pin in contact with the wafer, the new structure design can reduce the contact area of the chemical agent and water, is beneficial to drainage of the surface chemical agent and pure water of the wafer during rotation, and can achieve good cleaning effect by increasing the wafer flushing time and rotation speed, thereby improving the yield of the wafer electroplating process.

Description

Technical Field

[0001] This invention relates to the field of semiconductor technology, specifically to an electroplating ring, electroplating equipment, and a wafer cleaning method. Background Technology

[0002] As the feature size of semiconductor integrated circuit devices continues to shrink, the density of interconnect wiring in semiconductor devices increases dramatically. This leads to a rapid increase in parasitic RC coupling effects caused by resistance and capacitance in the interconnect system, affecting device speed. Furthermore, as linewidth gradually decreases, the resistance of the metal lines also increases. Therefore, the requirements for metal lines in devices are becoming increasingly stringent. Copper, as a metal with low resistance and good electron migration resistance, is widely used in the fabrication of metal wires. However, due to the difficulty in etching copper and the non-volatile nature of its byproducts, metal wires are primarily manufactured using electroplating processes.

[0003] Currently, in semiconductor electroplating processes for fabricating metal lines, the wafer needs to be in contact with the plating solution. Therefore, at the end of the plating process, the plating solution on the wafer surface must be thoroughly cleaned to prevent residual acid from causing copper residue to remain on the wafer surface. Thus, how to avoid residual acid at specific locations on the wafer surface is a pressing technical problem that needs to be solved. Summary of the Invention

[0004] The purpose of this invention is to provide an electroplating ring, electroplating equipment, and wafer cleaning method, which are applied to the electroplating process. By improving the structural design of the electroplating ring, acid residue is prevented at specific locations on the wafer surface after cleaning, thereby improving the yield of the wafer electroplating process.

[0005] To solve the above-mentioned technical problems, the present invention provides an electroplating ring, characterized in that:

[0006] Electroplated rings are used to hold wafers;

[0007] Positioning pins, located on the electroplated ring, are used to secure the wafer;

[0008] The positioning pin is divided into two parts: a base part that connects to the electroplating ring and a contact part that contacts the wafer;

[0009] The contact portion is designed as an elliptical cylinder structure.

[0010] Optionally, the height of the elliptical cylindrical structure is 3-8 mm.

[0011] Optionally, the contact portion is designed as at least two spaced-apart elliptical cylindrical structures.

[0012] Optionally, the interval between the spaced elliptical cylindrical structures is 1-2 mm.

[0013] Optionally, the end face of the elliptical cylinder structure is elliptical, with a major axis of 4-10mm and a minor axis of 2-4mm.

[0014] Optionally, the contact portion is designed as a single elliptical cylinder structure, the end face of which is elliptical, the major axis of the end face is 6-10mm, and the minor axis of the end face is 3-6mm.

[0015] Optionally, the tangential direction of the contact point between the elliptical cylinder and the wafer is at an angle of 30-90 degrees with the major axis of the end face of the elliptical cylinder structure.

[0016] The present invention also provides an electroplating apparatus, wherein the electroplating apparatus is constructed using an electroplating ring as described in any of the preceding claims, and the electroplating apparatus includes:

[0017] Electroplating equipment, used for wafer electroplating processes;

[0018] The cavity is used for wafer cleaning processes;

[0019] And the electroplated rings mentioned above.

[0020] The technical solution of the present invention also provides a wafer cleaning method, applied to the electroplating equipment described above and used to clean the wafer, comprising:

[0021] The wafer placed on the electroplating ring is rinsed, and the rinsing speed and time are increased.

[0022] Optionally, the wafer rinsing time should be greater than 10 seconds, and the wafer rinsing rotation speed should be greater than 350 revolutions per minute.

[0023] The advantages of this invention are that, compared to existing electroplating processes in semiconductor technology, this invention primarily improves the contact area between the positioning pin and the wafer. The new structural design reduces the contact area between chemicals and water, facilitating the drainage of chemical reagents and pure water from the wafer surface during rotary cleaning. Furthermore, increasing the wafer rinsing time and rotation speed achieves better cleaning results, thereby improving the yield of the wafer electroplating process. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the contact portion between the positioning pin and the wafer in a specific embodiment of the present invention.

[0025] Figure 2 This is a cross-sectional view of the contact portion between the improved positioning pin and the wafer in a specific embodiment of the present invention.

[0026] Figure 3 This is a cross-sectional view of the contact portion between the improved positioning pin and the wafer in another specific embodiment of the present invention.

[0027] Figure Labels

[0028] Wafer 1;

[0029] Electroplated ring 2;

[0030] Positioning pin 3;

[0031] Base section 4;

[0032] Existing contact part 51;

[0033] Improved contact parts 52, 53;

[0034] The existing contact part has a side length d;

[0035] The improved contact portion has its end face major axes a and e;

[0036] Improved contact portion end face short axis b, f;

[0037] Improved contact portion with high c, g. Detailed Implementation

[0038] The electroplating ring, electroplating equipment, and wafer cleaning method proposed in this invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0039] Please see Figure 1 This is a schematic diagram of the contact portion between the positioning pin and the wafer in a specific embodiment of the present invention.

[0040] Please see Figure 1 The invention provides an electroplating machine (not shown), including an electroplating ring 2 and positioning pins 3. This invention utilizes an existing electroplating machine to perform semiconductor electroplating on a wafer 1. The electroplating ring 2 is used to place the wafer 1; the positioning pins 3 are used to stabilize the wafer 1. Typically, the electroplating ring 2 has six positioning pins 3. Each positioning pin 3 can be divided into two parts: a base portion connected to the electroplating ring 2; and a contact portion that contacts the wafer 1, located above the base portion. The contact portion is designed as an elliptical cylindrical structure. A cavity (not shown) is used for wafer cleaning processes.

[0041] Those skilled in the art will understand that, currently, in the process of fabricating metal lines using semiconductor electroplating, since wafer 1 needs to come into contact with the electroplating solution, at the end of the semiconductor electroplating process, it is necessary to clean the electroplating solution off the surface of wafer 1 to prevent residual acid from causing copper metal residue on the surface of wafer 1 in subsequent processes.

[0042] For details, please refer to Figure 2In this embodiment, the contact portion 51, where the existing positioning pin 3 contacts the wafer 1, is redesigned from a cube with side length d (6mm) to an elliptical cylindrical structure. The base portion 4 of the positioning pin 3 is generally used for the connection between the contact portion 51 and the positioning pin. In semiconductor electroplating processes, bottlenecks in the electroplating machine cause the wafer 1 to wait a certain time after electroplating before being rinsed in the cavity. The original design of the electroplating ring 2 hinders the drainage of the electroplating solution during wafer 1 cleaning. This electroplating solution can include, but is not limited to, chemical reagents and pure water. Therefore, excessive electroplating solution remains on the surface of the wafer 1, especially at the contact portion 51 where the existing positioning pin 3 contacts the wafer 1. This results in copper metal residue after the subsequent chemical mechanical polishing process, severely impacting wafer yield.

[0043] The improved contact portion 52 is a single elliptical cylinder structure, wherein the height c of the elliptical cylinder structure is (3-8mm). The elliptical cylinder has upper and lower end faces, the lower end face is connected to the base portion 4, and the end faces of the elliptical cylinder structure are elliptical, with a major axis a of (6-10mm) and a minor axis b of (3-6mm). The elliptical cylinder is inclinedly disposed on the base portion 4, and in the actual direction of solution discharge, the major axis a of the end face of the elliptical cylinder structure forms an angle of (30-90 degrees), preferably (40-60 degrees), and more preferably 45 degrees, with the tangent of the contact point between the wafer and the positioning pin 3. The actual direction of solution discharge can be understood as follows: During the electroplating and cleaning of the wafer, the electroplating ring will drive the wafer to rotate at a certain speed in a fixed direction, which can be clockwise or counterclockwise. During the rotation, the liquid on the edge of the wafer will be flung out. The liquid has a flung speed on the edge of the wafer. The direction of the flung speed is exactly opposite to the tangential velocity direction of the wafer at the edge (i.e., the direction of wafer rotation). Here, the flung speed direction of the liquid is the actual direction of liquid discharge from the wafer.

[0044] Therefore, the new structural design is an elliptical cylindrical structure (i.e., an arc-shaped cylinder), which reduces the contact area between the positioning pin 3 and the wafer 1. This ensures that the positioning pin 3 does not obstruct the chemical reagents and pure water during the rotation cleaning of the wafer 1, thus facilitating the discharge of the electroplating solution and preventing residual liquid from remaining on the wafer 1 at the positioning pin 3 position. Simultaneously, the tilt angle of the elliptical cylindrical structure along the actual direction of solution discharge allows the chemical reagents and pure water located on the wafer to be guided out during rotation.

[0045] Furthermore, the improved contact portion 52 has a single elliptical cylinder structure, and the design increases the size of the elliptical cylinder, which can further reduce the contact area between the positioning pin 3 and the wafer while ensuring the stability of the wafer during rotation.

[0046] Therefore, the key to this embodiment is the improvement of the contact portion between the positioning pin 3 and the wafer 1. The new structural design can maintain the stability of the wafer 1 during rotational cleaning, and also facilitate the discharge of chemical reagents and pure water from the wafer surface during rotational cleaning in the electroplating chamber, so as not to cause residual acid corrosion of the wafer surface while waiting for further cleaning; thereby improving the yield of the wafer electroplating process.

[0047] Meanwhile, the contact structure of the improved positioning pin 3 of the present invention is not limited to the graphic structure in this embodiment.

[0048] In another specific embodiment of the present invention, a new process improvement is made based on the first specific embodiment.

[0049] Please see Figure 1 This is a schematic diagram of the contact portion between the positioning pin and the wafer in a specific embodiment of the present invention.

[0050] Please see Figure 1 The invention provides an electroplating machine (not shown), including an electroplating ring 2 and positioning pins 3. This invention utilizes an existing electroplating machine to perform semiconductor electroplating on a wafer 1. The electroplating ring 2 is used to place the wafer 1; the positioning pins 3 are used to stabilize the wafer 1. Typically, the electroplating ring 2 has six positioning pins 3. Each positioning pin 3 can be divided into two parts: a base portion connected to the electroplating ring 2; and a contact portion that contacts the wafer 1, located above the base portion. The contact portion is designed as an elliptical cylindrical structure. A cavity (not shown) is used for wafer cleaning processes.

[0051] Those skilled in the art will understand that, currently, in the process of fabricating metal lines using semiconductor electroplating, since wafer 1 needs to come into contact with the electroplating solution, at the end of the semiconductor electroplating process, it is necessary to clean the electroplating solution off the surface of wafer 1 to prevent residual acid from causing copper metal residue on the surface of wafer 1 in subsequent processes.

[0052] For details, please refer to Figure 3In this embodiment, the contact portion 51, where the existing positioning pin 3 contacts the wafer 1, is redesigned from a cube with side length d (6mm) to an elliptical cylindrical structure. The base portion 4 of the positioning pin 3 is generally used for the connection between the contact portion 51 and the positioning pin. In semiconductor electroplating processes, bottlenecks in the electroplating machine cause the wafer 1 to wait a certain time after electroplating before being rinsed in the cavity. The original design of the electroplating ring 2 hinders the drainage of the electroplating solution during wafer 1 cleaning. This electroplating solution can include, but is not limited to, chemical reagents and pure water. Therefore, excessive electroplating solution remains on the surface of the wafer 1, especially at the contact portion 51 where the existing positioning pin 3 contacts the wafer 1. This results in copper metal residue after the subsequent chemical mechanical polishing process, severely impacting wafer yield.

[0053] The improved contact portion 53 consists of at least two spaced-apart elliptical cylinder structures, which are disposed on the base portion 4 of the same positioning pin 3, with a spacing of 1-2 mm between the elliptical cylinders. The height g of the elliptical cylinder structure is (3-8 mm). Each elliptical cylinder has upper and lower end faces, with the lower end face connected to the base portion 4. The end faces of the elliptical cylinder structure are elliptical, with a major axis e of (4-10 mm) and a minor axis f of (2-4 mm). The elliptical cylinders are inclined on the base portion 4, and in the actual direction of solution discharge, the major axis e of the elliptical cylinder structure forms an angle of (30-90 degrees), preferably (40-60 degrees), and more preferably 45 degrees, with the tangent plane at the contact point between the wafer and the positioning pin 3. The actual direction of solution discharge can be understood as follows: During the electroplating and cleaning of the wafer, the electroplating ring will drive the wafer to rotate at a certain speed in a fixed direction, which can be clockwise or counterclockwise. During the rotation, the liquid on the edge of the wafer will be flung out. The liquid has a flung speed on the edge of the wafer. The direction of the flung speed is exactly opposite to the tangential velocity direction of the wafer at the edge (i.e., the direction of wafer rotation). Here, the flung speed direction of the liquid is the actual direction of liquid discharge from the wafer.

[0054] Therefore, the new structural design is an elliptical cylindrical structure (i.e., an arc-shaped cylinder), which reduces the contact area between the positioning pin 3 and the wafer 1. This ensures that the positioning pin 3 does not obstruct the chemical reagents and pure water during the rotation cleaning of the wafer 1, thus facilitating the discharge of the electroplating solution and preventing residual liquid from remaining on the wafer 1 at the positioning pin 3 position. Setting multiple elliptical cylinders on the same base improves the stability of the wafer during high-speed rotation. Simultaneously, the tilt angle of the elliptical cylinder structure along the actual direction of solution discharge guides the discharge of chemical reagents and pure water located on the wafer during rotation.

[0055] Furthermore, the improved contact portion 53 is a structure of three spaced-apart elliptical cylinders with a spacing of 1-1.5 mm between them. This structure can maintain the stability of the wafer 1 during rotational cleaning while minimizing the contact area between the contact portion 53 and the wafer.

[0056] Therefore, the key to this embodiment is the improvement of the contact portion between the positioning pin 3 and the wafer 1. The new structural design can maintain the stability of the wafer 1 during rotational cleaning, and also facilitate the discharge of chemical reagents and pure water from the wafer surface during rotational cleaning in the electroplating chamber, so as not to cause residual acid corrosion of the wafer surface while waiting for further cleaning; thereby improving the yield of the wafer electroplating process.

[0057] Meanwhile, the contact structure of the electroplated ring 2 and the improved positioning pin 3 required by the present invention is not limited to the graphic structure in this embodiment.

[0058] A further embodiment of the present invention provides an electroplating apparatus. The electroplating apparatus employs, for example... Figure 3 The electroplated ring is constructed as described above.

[0059] Please see Figure 1 The electroplating equipment is used in the electroplating process of wafers and includes: an electroplating machine (not shown) for performing wafer electroplating; an electroplating ring 2 for placing the wafer; a positioning pin 3 located on the electroplating ring 2 for stabilizing the wafer 1; the positioning pin 3 is divided into two parts: a base part connected to the electroplating ring and a contact part that contacts the wafer, wherein the contact part is designed as an elliptical cylinder structure; and a cavity (not shown) for performing wafer cleaning.

[0060] Specifically, electroplating equipment is currently used in the semiconductor electroplating process to create metal lines. Since wafer 1 needs to be in contact with the electroplating solution, at the end of the semiconductor electroplating process, the electroplating solution on the surface of wafer 1 needs to be cleaned to prevent residual acid from causing copper metal residue on the surface of wafer 1 in subsequent processes.

[0061] Therefore, this embodiment improves the electroplating ring 2 in the electroplating equipment.

[0062] Specifically, please refer to Figure 3In this embodiment, the existing contact portion 51, which is a cube with a side length d (6 mm), is redesigned as an elliptical cylinder structure. The improved contact portion 53 consists of at least two spaced elliptical cylinder structures, which are disposed on the base portion 4 of the same positioning pin 3, with a spacing of 1-2 mm between the elliptical cylinders. The height g of the elliptical cylinder structure is (3-8 mm). The elliptical cylinder has upper and lower end faces, with the lower end face connected to the base portion 4. The end face of the elliptical cylinder structure is elliptical, with a major axis e of (4-10 mm) and a minor axis f of (2-4 mm). The elliptical cylinder is inclined on the base portion 4, and in the actual direction of solution discharge, the major axis e of the elliptical cylinder structure forms an angle of (30-90 degrees), preferably (40-60 degrees), and more preferably 45 degrees, with the tangent plane at the contact point between the wafer and the positioning pin 3.

[0063] Therefore, the key to this embodiment is the improvement of the contact portion between the positioning pin 3 and the wafer 1. The new structural design can maintain the stability of the wafer 1 during rotational cleaning, and also facilitate the discharge of chemical reagents and pure water from the wafer surface during rotational cleaning in the electroplating chamber, so as not to cause residual acid corrosion of the wafer surface while waiting for further cleaning; thereby improving the yield of the wafer electroplating process.

[0064] Furthermore, the electroplating equipment described in the specific embodiments of the present invention uses an electroplating ring structure that is not limited to the graphic structure in this embodiment.

[0065] A specific embodiment of the present invention also provides a wafer cleaning method, which is applied to the electroplating equipment described above.

[0066] Please see Figure 1 It provides an electroplating machine, in which the contact part between the positioning pin and the wafer is designed as an elliptical cylinder structure; the wafer placed on the electroplating ring is rinsed, increasing the speed and time of wafer rinsing.

[0067] Specifically, this invention utilizes an existing electroplating machine to perform a semiconductor electroplating process on wafer 1. An electroplating machine (not shown) is provided, including: an electroplating ring 2 and positioning pins 3. The electroplating ring 2 is used to place the wafer 1. The positioning pins 3 are used to secure the wafer 1. Typically, the electroplating ring 2 has six positioning pins 3. Each positioning pin 3 can be divided into two parts: a base portion (not shown) connected to the electroplating ring 2; and a contact portion that contacts the wafer 1, located above the base portion. The contact portion is designed as an elliptical cylindrical structure. A cavity (not shown) is used for wafer cleaning processes.

[0068] Those skilled in the art will understand that, currently, in the process of fabricating metal lines using semiconductor electroplating, since wafer 1 needs to come into contact with the electroplating solution, at the end of the semiconductor electroplating process, it is necessary to clean the electroplating solution off the surface of wafer 1 to prevent residual acid from causing copper metal residue on the surface of wafer 1 in subsequent processes.

[0069] Furthermore, the contact portion is designed as at least two spaced-apart elliptical cylindrical structures.

[0070] For details, please refer to Figure 3 The improved contact portion 53 consists of at least two spaced-apart elliptical cylinder structures, which are disposed on the base portion of the same positioning pin 3, with a spacing of 1-2 mm between the elliptical cylinders. The height g of the elliptical cylinder structure is (3-8 mm). Each elliptical cylinder has upper and lower end faces, with the lower end face connected to the base portion 4. The end faces of the elliptical cylinder structure are elliptical, with a major axis e of (4-10 mm) and a minor axis f of (2-4 mm). The elliptical cylinders are inclinedly disposed on the base portion 4, and in the actual direction of solution discharge, the major axis e of the elliptical cylinder structure forms an angle of (30-90 degrees), preferably (40-60 degrees), and more preferably 45 degrees, with the tangent plane at the contact point between the wafer and the positioning pin 3. The actual direction of solution discharge can be understood as follows: During the electroplating and cleaning of the wafer, the electroplating ring will drive the wafer to rotate at a certain speed in a fixed direction, which can be clockwise or counterclockwise. During the rotation, the liquid on the edge of the wafer will be flung out. The liquid has a flung speed on the edge of the wafer. The direction of the flung speed is exactly opposite to the tangential velocity direction of the wafer at the edge (i.e., the direction of wafer rotation). Here, the flung speed direction of the liquid is the actual direction of liquid discharge from the wafer.

[0071] Therefore, the new structural design is an elliptical cylindrical structure (i.e., an arc-shaped cylinder), which reduces the contact area between the positioning pin 3 and the wafer 1. This ensures that the positioning pin 3 does not obstruct the chemical reagents and pure water during the rotation cleaning of the wafer 1, thus facilitating the discharge of the electroplating solution and preventing residual liquid from remaining on the wafer 1 at the positioning pin 3 position. Simultaneously, the tilt angle of the elliptical cylindrical structure along the actual direction of solution discharge allows the chemical reagents and pure water located on the wafer to be guided out during rotation.

[0072] Furthermore, the improved contact portion 53 is a structure of three spaced-apart elliptical cylinders with a spacing of 1-1.5 mm between them, which can maintain the stability of wafer 1 during rotational cleaning.

[0073] Furthermore, in this embodiment, the wafer rinsing time should be greater than 10 seconds, and the wafer rinsing rotation speed should be greater than 350 revolutions per minute. Specifically, after copper metal is deposited on wafer 1, insufficient cleaning of the electroplating cavity can lead to acid residue, resulting in copper residue. Therefore, by increasing the wafer rinsing time and rotation speed, a good cleaning effect can be achieved.

[0074] Therefore, the key to this embodiment is the improvement of the contact portion between the positioning pin 3 and the wafer 1. The new structural design can maintain the stability of the wafer 1 during rotational cleaning, and also facilitate the discharge of chemical reagents and pure water from the wafer surface during rotational cleaning in the electroplating chamber, so as not to cause residual acid corrosion of the wafer surface while waiting for further cleaning; thereby improving the yield of the wafer electroplating process.

[0075] The above description is only a preferred embodiment of the present invention. It should be noted that those skilled in the art can make several improvements and modifications without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. An electroplated ring, characterized in that, include: Electroplated rings are used to hold wafers; Positioning pins, located on the electroplated ring, are used to secure the wafer; The positioning pin is divided into two parts: a base part that connects to the electroplating ring and a contact part that contacts the wafer; The contact portion is designed as an elliptical cylinder structure; the end face of the elliptical cylinder structure is elliptical; the elliptical cylinder is inclinedly disposed on the base portion, and in the actual direction of solution discharge, the major axis of the end face of the elliptical cylinder structure forms an angle of 30-90 degrees with the tangent of the contact point between the wafer and the positioning pin.

2. The electroplating ring according to claim 1, characterized in that, The height of the elliptical cylindrical structure is 3-8mm.

3. The electroplating ring according to claim 2, characterized in that, The contact portion is designed as at least two spaced-apart elliptical cylindrical structures.

4. The electroplating ring according to claim 3, characterized in that, The intervals between the spaced elliptical cylindrical structures are 1-2 mm.

5. The electroplating ring according to claim 3, characterized in that, The major axis of the end face is 4-10mm, and the minor axis of the end face is 2-4mm.

6. The electroplating ring according to claim 2, characterized in that, The contact part is designed as a single elliptical cylinder structure, the end face of which is elliptical, the major axis of which is 6-10mm, and the minor axis of which is 3-6mm.

7. An electroplating device, characterized in that, include: Electroplating equipment, used for wafer electroplating processes; The cavity is used for wafer cleaning processes; And the electroplated ring as described in any one of claims 1-6.

8. A wafer cleaning method, applied to the electroplating equipment as described in claim 7 and used to clean the wafer, characterized in that, include: The wafer placed on the electroplating ring is rinsed, and the rinsing speed and time are increased.

9. The wafer cleaning method according to claim 8, characterized in that, The wafer rinsing time should be greater than 10 seconds, and the wafer rinsing speed should be greater than 350 revolutions per minute.

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