Electroplating device

Abstract

The invention relates to the technical field of semiconductor manufacturing, in particular to an electroplating device which comprises an electroplating cavity, an electroplating device body and an electroplating device body. The rotating assembly is used for clamping and rotating the wafer, so that the lower surface of the wafer is in contact with the electroplating liquid; the device comprises an electroplating cavity, a rectification oscillation plate and a driving part, the rectification oscillation plate is arranged in the electroplating cavity, a connecting part is arranged between the driving part and the rectification oscillation plate, and the rectification oscillation plate is driven by the driving part to do reciprocating motion in the electroplating cavity in the horizontal direction of electroplating liquid. The rectification oscillation plate and the driving part are arranged, the rectification oscillation plate is driven by the driving part to do reciprocating motion in the electroplating liquid in the horizontal direction, transverse electroplating liquid flow is provided for the surface of a wafer, mass transfer of the electroplating liquid on the surface of the wafer in the electroplating process is increased, the problem that mass transfer in complex pattern deep holes in the wafer is poor is solved, meanwhile, the wafer yield is increased, and the production cost is reduced. The electroplating uniformity is improved, and the influence of the fringe effect, low or uneven wafer notch and electroplating liquid mass transfer speed on electroplating is weakened.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor manufacturing, and in particular to an electroplating device. Background Art

[0002] In the integrated circuit (IC) manufacturing process, electroplating technology is commonly used to deposit one or more conductive metal layers on semiconductor wafer substrates due to its advantages such as process simplicity, low cost, and ease of mass production. This is to form single-layer or multi-layer metal interconnects between various semiconductor wafer substrate features. During electroplating, electrical contacts are formed on a seed layer at the periphery of the wafer, and the wafer is electrically biased to act as a cathode, bringing the wafer into contact with an electrolyte containing the metal ions to be plated.

[0003] There are some factors that affect the uniformity of electroplating during the electroplating process, such as the edge effect caused by the resistance of the wafer itself, the current crowding near the notch area of ​​the wafer, the electric field irregularity caused by pattern changes, and other electric field uniformity problems; as well as the high aspect ratio holes caused by the slightly thick edge of the photoresist coating that are prone to voids, and the electrolyte forming a diffusion layer on the wafer surface that reduces mass transfer, and other flow field uniformity problems.

[0004] In order to improve the differentiation of coating thickness at the edge of a wafer and enhance electroplating uniformity, the present application proposes an electroplating device. Summary of the Invention

[0005] The object of the present invention is to provide an electroplating device to solve the problem of uneven thickness of the coating on the edge of a wafer in the prior art.

[0006] In order to achieve the above object, the technical solution of the present invention is as follows: Electroplating equipment, comprising: an electroplating chamber, wherein an electroplating solution is arranged inside the chamber; a rotating assembly for clamping and rotating the wafer so that the lower surface of the wafer contacts the electroplating solution; A rectifier oscillation plate and a driving member, the rectifier oscillation plate is arranged in the electroplating chamber, a connecting member is arranged between the driving member and the rectifier oscillation plate, and the rectifier oscillation plate moves repeatedly in the electroplating chamber along the horizontal direction of the electroplating liquid under the drive of the driving member.

[0007] Preferably, the rectifier oscillation plate includes a base plate and a push plate arranged on the base plate, a first opening is arranged on the base plate, and a second opening is arranged on the push plate; the rotating assembly includes a circular cup, a conical portion, a support rod, a top plate, a main shaft and a motor, the motor is connected to the top plate, the conical portion is located between the top plate and the circular cup, and the support rod connects the top plate, the conical portion and the circular cup in sequence.

[0008] Preferably, the bottom plate is made of a high-resistance material, and a shielding area is provided on the bottom plate.

[0009] Preferably, a fence portion is provided at the edge of the bottom plate, and the height of the fence portion is higher than the bottom plate and lower than the height of the push plate.

[0010] Preferably, the top of the push plate is wavy or sawtooth-shaped.

[0011] Preferably, the second openings on the push plate are provided in two rows, the two rows of second openings are evenly distributed on the push plate, and the second openings are rectangular or circular.

[0012] Preferably, at least one side of the cross section of the push plate is configured as a curved surface or an inclined surface.

[0013] Preferably, the aperture of the first opening on the bottom plate close to the edge of the bottom plate is smaller than the aperture of the first opening close to the center of the bottom plate.

[0014] Preferably, the push plates include high push plates and low push plates of different heights that are arranged crosswise with each other.

[0015] Preferably, the push plates are cross-distributed in a grid shape.

[0016] Compared with the prior art, the electroplating device of this application has the following beneficial effects: The present invention is provided with a rectifying oscillating plate and a driving member. The rectifying oscillating plate is driven by the driving member to repeatedly move in the horizontal direction in the electroplating solution, thereby providing a lateral electroplating liquid flow to the wafer surface, increasing the mass transfer of the electroplating liquid on the wafer surface during the electroplating process, solving the problem of poor mass transfer in deep holes with complex patterns on the wafer, and at the same time improving the wafer yield, improving the uniformity of electroplating, and reducing the influence of edge effects, wafer gaps and slow or uneven mass transfer of the electroplating solution on electroplating. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 A schematic structural diagram of an electroplating device provided in an embodiment of the present invention; Figure 2 A schematic structural diagram of an electroplating chamber provided in an embodiment of the present invention; Figure 3 for Figure 2 A in the middle is an enlarged schematic diagram; Figure 4 A schematic structural diagram of a rectifier oscillator plate provided in an embodiment of the present invention; Figure 5 A schematic cross-sectional view of a rectifier oscillator plate provided in an embodiment of the present invention; Figure 6 A schematic structural diagram of a push plate provided in an embodiment of the present invention; Figure 7 Another structural schematic diagram of a push plate provided in an embodiment of the present invention; Figure 8A schematic diagram of a distribution structure of the second openings on the push plate provided in an embodiment of the present invention; Figure 9 A schematic diagram of another distribution structure of the second openings on the push plate provided in an embodiment of the present invention; Figure 10 A schematic diagram of a cross section of a push plate provided in an embodiment of the present invention; Figure 11 Another schematic diagram of a cross section of a push plate provided in an embodiment of the present invention; Figure 12 Another schematic diagram of a cross section of a push plate provided in an embodiment of the present invention; Figure 13 A schematic cross-sectional view of another embodiment of the rectifier oscillator plate provided by the present invention; Figure 14 A schematic cross-sectional view of another embodiment of the rectifier oscillator plate provided by the present invention; Figure 15 A schematic structural diagram of another rectifier oscillator plate provided in an embodiment of the present invention; Figure 16 is a graph showing the relationship between current density and radial position of the wafer; Figure 17 is a graph showing the relationship between the coating thickness and the radial position of the wafer. DETAILED DESCRIPTION

[0018] The following is further described in detail through specific implementation methods: The figure marks in the drawings of the specification include: electroplating chamber 1, rectifier oscillation plate 2, driving part 3, connecting part 4, bottom plate 5, push plate 6, first opening 7, second opening 8, shielding area 9, fence part 10, round cup 101, conical part 102, support rod 103, top plate 104, main shaft 105, and motor 106.

[0019] As attached Figure 1-2 As shown, this embodiment shows an electroplating device, including an electroplating chamber 1, a rotating assembly, a rectifying oscillating plate 2, and a driving member 3. The electroplating chamber 1 contains a plating solution; the rotating assembly is used to clamp and rotate a wafer so that the lower surface of the wafer contacts the plating solution; the rectifying oscillating plate 2 is disposed within the electroplating chamber 1, and a connecting member 4 is provided between the driving member 3 and the rectifying oscillating plate 2. Driven by the driving member 3, the rectifying oscillating plate 2 repeatedly moves horizontally along the plating solution within the electroplating chamber 1.

[0020] The electroplating device of this embodiment uses a driving component 3 to drive the rectifier oscillation plate 2 to converge the plating liquid and current in the plating chamber 1, and push the plating liquid laterally, thereby improving the uniformity of the electric field in the plating chamber 1 and the mass transfer of the plating liquid flow field.

[0021] Specifically, the electroplating chamber 1 includes an inner wall and an outer wall. The driving member 3 is a motor, and the connecting member 4 is a retractable thread structure. The rectifier oscillating plate 2 controls the retractable thread structure to oscillate horizontally via an external motor.

[0022] The rotating assembly includes a cup 101, a conical portion 102, support rods 103, a top plate 104, a spindle 105, and a motor 106. The motor 106 is connected to the top plate 104. The conical portion 102 is located between the top plate 104 and the cup 101. The support rods 103 sequentially connect the top plate 104, the conical portion 102, and the cup 101. The cup 101 is used to securely hold a wafer, while the conical portion 102 securely clamps the wafer within the cup 101. The rotating assembly is supported by the support rods 103, which are connected to the top plate 104. The cup 101, conical portion 102, support rods 103, and the top plate 104 are driven by the motor 106 via the spindle 105 connected to the top plate 104. During electroplating, the spindle 105 transmits torque from the motor 106 to the conical portion 102, thereby rotating the wafer held therein. When the wafer is inserted between the circular cup 101 and the conical portion 102 , the conical portion 102 engages with the circular cup 101 to fix the wafer in the device, thereby exposing a working surface on one side of the wafer for contact with the electroplating solution.

[0023] Among them Figure 3-4 As shown, the rectifying oscillating plate 2 includes a base plate 5 and a push plate 6 disposed on the base plate 5. The base plate 5 is provided with a first opening 7, and the push plate 6 is provided with a second opening 8. During electroplating, the plating liquid flows upward from the first opening 7 of the base plate 5 and is pushed horizontally by the push plate 6. The second opening 8 on the push plate 6 serves as a flow regulating structure to help enhance fluid flow.

[0024] Specifically, the base plate 5 is made of a high-resistance material, so that the wafer surface receives a uniform electric field through the evenly distributed first openings 7 on the base plate 5 during the electroplating process. The high-resistance material can be polyethylene, polyvinylidene fluoride, polypropylene, etc. A shielding area 9 is provided on the base plate 5.

[0025] The rectifier oscillator plate 2 reciprocates along the M direction via a retractable threaded structure, providing lateral flow to the wafer surface. This enhances mass transfer of the plating solution across the wafer surface during processing and addresses the issue of poor mass transfer within deep holes with complex patterns on the wafer. The push plate 6 is fixed to the base plate 5. The base plate 5 and the shielding area 9 shield the chaotic electric field lines, addressing the problem of coating tilt caused by irregular electric field lines. During wafer processing, as the wafer rotates and the rectifier oscillator plate 2 translates, the electric field lines in the center of the wafer are evenly shielded. However, due to the presence of the shielding area 9, the edges of the wafer are evenly shielded compared to the center. When the wafer notch overlaps with the shielding area 9, the rectifier oscillator plate 2 is allowed to stop, addressing the problem of thicker metal coating near the notch due to current congestion in the notch. The frequency of overlap between the wafer notch and the shielding area 9 is determined by the wafer rotation speed and the translation speed and amplitude of the rectifier oscillator plate 2. Furthermore, by adjusting the movement amplitude of the rectifying oscillating plate 2 , edge shielding effects of varying degrees can be achieved.

[0026] like Figure 4-5 As shown, in some embodiments, a fence portion 10 is provided at the edge of the bottom plate 5, and the height of the fence portion 10 is higher than the bottom plate 5 and lower than the height of the push plate 6. After the first opening 7 of the bottom plate 5 converges the electric field and flow field of the plating solution, a uniformly distributed second opening 8 is provided on the push plate 6. The design of the first opening 7 and the second opening 8 helps to disrupt the flow pattern, and provides a variety of possible flow directions for the plating solution with a single flow direction during the processing. The fence portion 10 reduces the diffusion of the plating solution above the rectifier oscillation plate 2 to the surroundings when it moves, and accelerates the overflow of the plating solution returned from the wafer to the surroundings. While ensuring that the plating solution between the rectifier oscillation plate 2 and the wafer attacks the wafer surface in a directionally directed manner, the plating solution on the wafer surface is quickly replaced.

[0027] like Figure 6-7 As shown, in some embodiments, the top of the push plate 6 is in a wave shape or a sawtooth shape.

[0028] like Figure 8-9 As shown, the second openings 8 on the push plate 6 are arranged in two rows, and the two rows of second openings 8 are evenly distributed on the push plate 6 . The second openings 8 are rectangular or circular.

[0029] The shape of the top of the push plate 6 and the shape of the second openings 8 can match each other, and the second openings 8 are evenly distributed on the push plate 6 to achieve the best disturbance effect.

[0030] Among them, at least one side of the cross section of the push plate 6 is set to be an arc surface or an inclined surface. Figure 10-12The push plate 6 is shown with a triangular cross section, a spire cross section, and a vase cross section. The push plate 6 should have at least a partially inclined / curved side surface so that it can impart an oblique upward force to the plating solution during flow disturbance, accelerating the plating solution to rise and contact the wafer opening pattern at an oblique angle, making it easier for the plating solution to reach the deepest openings of the wafer.

[0031] like Figure 13 As shown, the aperture of the first opening 7 on the bottom plate 5 near the edge of the bottom plate 5 is smaller than the aperture of the first opening 7 near the center of the bottom plate 5. At different radii with the same center, the first opening 7 of the bottom plate 5 of the rectifying oscillating plate 2 can have different opening diameters. Smaller diameter first openings 7 can be provided at the edge of the rectifying oscillating plate 2, allowing the rectifying oscillating plate 2 to produce periodic edge shielding at the edge of the wafer with a smaller movement amplitude, rather than relying solely on the shielding area 9 to provide edge shielding.

[0032] like Figure 14 As shown, the pusher plates 6 include tall pusher plates 6 and short pusher plates 6 of varying heights, arranged interlaced with each other. The pusher plates 6 can be more than a single structure; the bottom plate 5 of the rectifying oscillating plate 2 can be provided with tall pusher plates 6 and short pusher plates 6 of varying shapes, interlaced alternately. While the tall pusher plates 6 provide a basic flow disturbance, the short pusher plates 6 redirect some fluid flow, creating a cross-flow that impacts the wafer surface, enhancing mass transfer in the plating solution.

[0033] like Figure 15 As shown, push plates 6 are arranged in a grid pattern. They can extend in a variety of directions, forming a grid of intersecting rectangles. The rectifier oscillating plate 2 reciprocates horizontally, pushing the plating solution along the sides and diagonally of the push plates 6, creating a more complex flow field and improving mass transfer efficiency.

[0034] Reference Figure 16 and 17 , shows the simulated functional relationship curve of current density and plating thickness with radial distance on the wafer. The position of "0 mm" on the X-axis corresponds to the center of the wafer, and the position of "150 mm" on the X-axis corresponds to the edge of a 300 mm wafer. It can be clearly seen in the figure that the use of the high resistance rectifier oscillator plate 2 has a significant effect on the uniformity of the wafer plating thickness. According to Figure 16 As shown in FIG, the presence of the high resistance rectifier oscillator plate 2 reduces the current density variation in different regions on the wafer by about 71%. The final intuitive effect of electroplating on the wafer is as follows Figure 17 As shown, the overall electroplating speed and uniformity are significantly improved after the introduction of the high-resistance rectifier oscillator plate 2. After 30 seconds of electroplating, the coating thickness at the center of the wafer is increased by about 101% compared to when the high-resistance rectifier oscillator plate 2 is not present.

[0035] The above is only an embodiment of the present invention, and the common knowledge such as the specific structure and characteristics of the scheme is not described in detail here. It should be pointed out that for those skilled in the art, several variations and improvements can be made without departing from the structure of the present invention, and these should also be regarded as the scope of protection of the present invention. These will not affect the effect of the implementation of the present invention and the practicality of the patent. The scope of protection required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.

Claims

1. An electroplating device, characterized in that include: an electroplating chamber (1) in which an electroplating solution is arranged; a rotating assembly for clamping and rotating the wafer so that the lower surface of the wafer contacts the electroplating solution; A rectifier oscillating plate (2) and a driving member (3), wherein the rectifier oscillating plate (2) is arranged in an electroplating cavity (1), a connecting member (4) is arranged between the driving member (3) and the rectifier oscillating plate (2), and the rectifier oscillating plate (2) is driven by the driving member (3) to repeatedly move in the electroplating cavity (1) along the horizontal direction of the electroplating liquid.

2. The electroplating device according to claim 1, characterized in that The rectifier oscillating plate (2) comprises a bottom plate (5) and a push plate (6) arranged on the bottom plate (5), wherein a first opening (7) is arranged on the bottom plate (5) and a second opening (8) is arranged on the push plate (6); the rotating assembly comprises a circular cup (101), a conical portion (102), a support rod (103), a top plate (104), a main shaft (105) and a motor (106), wherein the motor (106) is connected to the top plate (104), the conical portion (102) is located between the top plate (104) and the circular cup (101), and the support rod (103) sequentially connects the top plate (104), the conical portion (102) and the circular cup (101).

3. The electroplating device according to claim 2, characterized in that The bottom plate (5) is made of a high-resistance material, and a shielding area (9) is provided on the bottom plate (5).

4. The electroplating device according to claim 2 or 3, characterized in that: A fence portion (10) is provided at the edge of the bottom plate (5), and the height of the fence portion (10) is higher than the bottom plate (5) and lower than the height of the push plate (6).

5. The electroplating device according to claim 4, characterized in that: The top of the push plate (6) is in a wave shape or a sawtooth shape.

6. The electroplating device according to claim 4, characterized in that: The second openings (8) on the push plate (6) are arranged in two rows, and the two rows of second openings (8) are evenly distributed on the push plate (6), and the second openings (8) are rectangular or circular.

7. The electroplating device according to claim 4, characterized in that: At least one side of the cross section of the push plate (6) is configured as a curved surface or an inclined surface.

8. The electroplating device according to claim 4, characterized in that: The aperture of the first opening (7) on the bottom plate (5) close to the edge of the bottom plate (5) is smaller than the aperture of the first opening (7) close to the center of the bottom plate (5).

9. The electroplating device according to claim 2, characterized in that: The push plate (6) comprises a high push plate (6) and a low push plate (6) which are arranged crosswise with each other and have different heights.

10. The electroplating device according to claim 2, characterized in that: The push plates (6) are cross-distributed in a grid shape.

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