Wafer electroplating equipment

Abstract

The invention relates to wafer electroplating equipment, which comprises an electroplating chamber, a first liquid inlet, a second liquid inlet, a first liquid outlet and a second liquid outlet, 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 in the electroplating chamber; the flow guide element comprises a cavity, a third liquid inlet and at least one first liquid outlet which are communicated with one another; at least one first liquid outlet is provided with a flow blocking device, and the flow blocking device is used for controlling the flow direction of the electroplating liquid passing through the first liquid outlet; a through hole is further formed in the flow guide element and penetrates through the flow guide element. The flow blocking cap of the wafer electroplating equipment is spirally distributed clockwise / anticlockwise or deflects in the same direction, so that the flow direction of electroplating liquid is forcibly changed, controllable rotational flow or laminar flow is formed, the centrifugal effect brought by a rotating assembly is counteracted, and the thickness of a plating layer at the edge and the center of a wafer is more uniform.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, in particular to wafer electroplating equipment. 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] During the electroplating process, many factors can lead to uneven thickness of the metal deposited on semiconductor wafers. To improve plating uniformity, reduce the thickness of the diffusion boundary layer, and quickly replenish consumed reactants, a multi-directional flow field is often introduced. However, because the inlet and outlet of the anisotropic flow field are often concentrated at the wafer edge, and the plating solution near the wafer surface rotates with the wafer, the plating solution on the wafer surface is more likely to form eddies. This results in a lower pressure at the center of the wafer than at the edge, causing the mass transfer intensity of the plating solution at the center to be lower than that at the edge.

[0004] High-speed oscillation of the plating solution near the chip surface can improve the above problems. However, as the amplitude / frequency increases, bubbles will inevitably be introduced or heat will be generated, which poses a great challenge to the yield of the electroplated chip and the control of the corresponding electroplating process.

[0005] In order to improve the flow problem of electroplating solution on the surface of a wafer, and to enhance the uniformity of the electroplating production process and the yield rate of the plated chips, the present invention proposes a wafer electroplating device. Summary of the Invention

[0006] The object of the present invention is to provide a wafer electroplating device to solve the problem of uneven thickness of the wafer edge coating in the prior art.

[0007] In order to achieve the above object, the technical solution of the present invention is as follows: The wafer electroplating equipment includes: an electroplating chamber, which is provided with a first liquid inlet and a second liquid inlet; a rotating assembly, which is used to clamp and rotate the wafer so that the lower surface of the wafer contacts the plating liquid in the electroplating chamber; a flow-guiding element, which includes a connected cavity, a third liquid inlet and at least one first liquid outlet; at least one of the first liquid outlets is provided with a flow-blocking device, which is used to control the flow direction of the plating liquid passing through the first liquid outlet; the flow-guiding element is also provided with a through hole, which passes through the flow-guiding element.

[0008] Preferably, the flow blocking device includes a flow blocking cap and / or a flow blocking strip.

[0009] Preferably, the angle between the baffle cap on the first liquid outlet and the first liquid outlet is in a clockwise or counterclockwise spiral distribution.

[0010] Preferably, a second liquid outlet is provided on the flow-guiding element, and the cross-sectional area of the second liquid outlet is larger than the cross-sectional area of the first liquid outlet.

[0011] Preferably, the angle direction of the baffle cap and the first liquid outlet is set to the same side, and the guide element is provided with a third liquid outlet on the side away from the angle direction of the baffle cap and the first liquid outlet, and the cross-sectional area of the third liquid outlet is larger than the cross-sectional area of the first liquid outlet.

[0012] Preferably, the baffle cap is in the shape of a shell with a dome as a whole, and the inner side wall of the guide cap opposite to the first liquid outlet is set as an arc surface.

[0013] Preferably, the first liquid outlet and the through hole are cross-distributed on the flow guiding element.

[0014] Preferably, the shape of the first liquid outlet is set to be circular, elliptical, U-shaped or rectangular.

[0015] Preferably, the third liquid inlet is arranged on the side wall of the flow guiding element.

[0016] Preferably, the rotating assembly includes a 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 cup, and the support rod sequentially connects the top plate, the conical portion and the cup.

[0017] Compared with the prior art, the wafer electroplating equipment of this application has the following beneficial effects: The wafer electroplating equipment of the present invention forms a layered and partitioned liquid supply mode through the first liquid inlet, the second liquid inlet and the third liquid inlet combined with the guide element, thereby avoiding local uneven concentration of the electroplating solution and ensuring the consistency of ion distribution on the wafer surface.

[0018] The baffle cap changes the direction of the plating solution by clockwise / counterclockwise spiral distribution or unidirectional deflection, forming a controllable swirl or laminar flow, offsetting the centrifugal effect caused by the rotating component, and making the coating thickness at the edge and center of the wafer more uniform.

[0019] The second or third liquid outlet has a larger cross-sectional area, which can enhance the flow rate at the center or a specific area of the wafer, thereby compensating for the problem of insufficient deposition in the center area caused by fluid inertia in traditional electroplating.

[0020] The dome shell and the inner arc surface can smoothly guide the electroplating liquid, reduce the flow shear force, reduce the generation of bubbles, and improve the density of the coating.

[0021] The setting of the baffle strip further strengthens the directional control of the flow field and reduces the negative impact of fluid fluctuations on the coating. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 An exploded schematic diagram of a wafer electroplating apparatus provided by an embodiment of the present invention; Figure 2 A schematic cross-sectional view of a wafer electroplating apparatus according to an embodiment of the present invention; Figure 3 A schematic structural diagram of a flow guide element provided in an embodiment of the present invention; Figure 4 A schematic structural diagram of a flow guide element provided in an embodiment of the present invention; Figure 5 A schematic structural diagram of another flow guide element provided in an embodiment of the present invention; Figure 6 A schematic structural diagram of another flow guide element provided in an embodiment of the present invention; Figure 7 A structural schematic diagram of a flow guide element is also provided for an embodiment of the present invention. DETAILED DESCRIPTION

[0023] The following is further described in detail through specific implementation methods: The figure marks in the drawings of the specification include: electroplating chamber 1, first liquid inlet 2, second liquid inlet 3, rotating assembly 4, chip 5, anode film 6, guide element 7, third liquid inlet 8, first liquid outlet 9, baffle cap 10, through hole 11, second liquid outlet 12, third liquid outlet 13, baffle bar 14, first flow direction 15, second flow direction 16, cavity 17, round cup 101, cone 102, support rod 103, top plate 104, main shaft 105, motor 106.

[0024] As attached Figure 1-7 As shown, this embodiment shows a wafer electroplating apparatus, including an electroplating chamber 1, in which an electroplating liquid is disposed. The electroplating chamber 1 is provided with a first liquid inlet 2 and a second liquid inlet 3. The electroplating chamber 1 is generally cylindrical, with the first liquid inlet 2 disposed at the center of the bottom and the second liquid inlet 3 disposed at the edge of the bottom.

[0025] The wafer electroplating apparatus of this embodiment further includes a rotating assembly 4 for clamping and rotating a wafer 5 so that the lower surface of the wafer 5 contacts the electroplating solution within the electroplating chamber 1; an anode film 6 disposed within the electroplating chamber 1 and located above the first liquid inlet 2; a flow-guiding element 7 comprising a interconnected cavity 17, a third liquid inlet 8, and at least one first liquid outlet 9; a flow-blocking device disposed on the at least one first liquid outlet 9 for controlling the flow direction of the electroplating solution passing through the first liquid outlet 9. The flow-guiding element 7 also includes a through-hole 11 extending through the flow-guiding element 7.

[0026] The electroplating liquid of the chip 5 electroplating equipment of this embodiment has a first flow direction 15 and a second flow direction 16. The first flow direction 15 flows into the electroplating chamber 1 through the first liquid inlet 2, and then flows to the chip 5 through the through hole 11; the second flow direction 16 flows into the electroplating chamber 1 through the second liquid inlet 3, and then enters the cavity 17 through the third liquid inlet 8, and finally flows to the chip 5 through the first liquid outlet 9.

[0027] In which, the baffle device of this embodiment includes a baffle cap 10 and / or a baffle bar 14, that is, in some embodiments, the baffle cap 10 or the baffle bar 14 can be set separately to control the flow direction of the electroplating solution through the first liquid outlet 9, or the baffle cap 10 and the baffle bar 14 can be set at the same time to control the flow direction of the electroplating solution through the first liquid outlet 9.

[0028] Specifically, the first liquid outlet 9 and the through hole 11 are cross-distributed on the flow guiding element 7 . The third liquid inlet 8 is provided on the side wall of the flow guiding element 7 .

[0029] like Figure 2 As shown, this embodiment provides a flow guide element 7, a first liquid inlet 2, and a second liquid inlet 3, so that the plating liquid reaching the surface of the chip 5 is divided into two flow directions. The plating liquid in the first flow direction enters from the first liquid inlet 2 of the electroplating chamber 1, passes upward through the anode membrane 6 and the through hole 11 of the flow guide element 7 in sequence, and then attacks the surface of the chip 5 in a vertical direction. The plating liquid in the second flow direction enters from the second liquid inlet 3 of the electroplating chamber 1, passes through the third liquid inlet 8 of the flow guide element 7, fills the cavity 17 of the flow guide element 7, and then passes through the angle area between the first liquid outlet 9 of the flow guide element 7 and the baffle cap 10, and impacts the surface of the chip 5 at an inclined angle. The combination of the two flow directions, namely the vertical flow and the inclined flow, can substantially improve the permeability of the recessed characteristic deep holes of the chip 5, thereby improving the transfer of the electrolyte. The vertical component of the inclined flow is more conducive to the discharge of bubbles and improves micropore filling defects. The arrangement of the first liquid outlet 9 close to the processing side of the wafer 5 can significantly increase the liquid flow rate on the surface of the wafer 5, uniformly reduce the thickness of the diffusion boundary layer, and quickly replenish the consumed reaction substances.

[0030] The flow guide element 7 can be made of a resistive material such as polyethylene, polyvinylidene fluoride, or polypropylene. Using these materials to make the flow guide element 7 also significantly reduces the terminal effect. The terminal effect refers to the fact that after the seed layer is coated on the wafer 5, the current resistance in the seed layer is high relative to the resistance in the cathode plating solution. The difference between the central resistance of the wafer 5 and the edge resistance of the wafer 5 is large, resulting in uneven radial current distribution. The flow guide element 7 made of a high-resistance material effectively increases the resistance of the plating solution, balancing the uniformity of radial electroplating.

[0031] Among them Figure 1 As shown, the rotary assembly 4 includes a cup 101, a conical portion 102, a support rod 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 rod 103 sequentially connects the top plate 104, the conical portion 102, and the cup 101. The cup 101 is used to securely hold the wafer 5, and the conical portion 102 securely clamps the wafer 5 within the cup 101. The rotary assembly 4 is supported by the support rod 103, which is connected to the top plate 104. The cup 101, the conical portion 102, the support rod 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 5 held therein. When the wafer 5 is inserted between the cup 101 and the conical portion 102 , the conical portion 102 engages with the cup 101 to fix the wafer 5 in the device, thereby exposing a working surface on one side of the wafer 5 for contact with the electroplating solution.

[0032] The flow guide element 7 is configured as a hollow container for holding the plating solution, and has one or more liquid inlets, a first liquid outlet 9, and a through hole 11. The first liquid outlet 9 of the flow guide element 7 has a baffle cap 10 to change the direction of the plating solution impacting the surface of the wafer 5. The angle between the baffle cap 10 and the first liquid outlet 9 can have different opening directions, such as Figure 3 As shown, the baffle cap 10 on the first liquid outlet 9 is arranged in a clockwise or counterclockwise spiral with respect to the first liquid outlet 9. The spiral direction can be the same as or opposite to the rotation direction of the wafer 5. When the rotation of the wafer 5 forms a vortex on the surface of the wafer 5, the plating solution with the second flow direction amplifies the impact force of the vortex on the surface of the wafer 5, or reversely impacts the patterned deep holes on the surface of the wafer 5, thereby increasing the fluid mass transfer intensity.

[0033] like Figure 4As shown, in some embodiments, a second liquid outlet 12 is provided on the flow guide element 7, and the cross-sectional area of the second liquid outlet 12 is greater than the cross-sectional area of the first liquid outlet 9; the second liquid outlet 12 is opposite to the center of the wafer 5. When the wafer 5 rotates, the plating liquid on the surface of the wafer 5 is more likely to form vortices. This results in the pressure in the center of the wafer 5 being lower than the pressure at the edge of the wafer 5, making the mass transfer intensity of the plating liquid in the center of the wafer 5 lower than that at the edge. In this case, the second liquid outlet 12 is provided directly opposite to the center of the wafer 5, and the plating liquid passes through the second liquid outlet 12 to compensate for the low mass transfer intensity in the center of the wafer 5.

[0034] like Figure 5 As shown in the figure, the electroplating solution flowing out of all first liquid outlets 9 has an outward-diverging flow direction. Similarly, in some embodiments, the flow cap 10 can also be configured to have an inward-concentrating flow direction. The center point of divergence and concentration can be offset according to the actual pattern shape to be plated on the wafer 5, rather than being fixed at the center position of the flow guide element 7. This is extremely helpful for customizing the flow field direction.

[0035] like Figure 6 As shown, in some embodiments, the angle between the baffle cap 10 and the first liquid outlet 9 is arranged to face the same side, and the flow-guiding element 7 is provided with a third liquid outlet 13 on a side facing away from the angle between the baffle cap 10 and the first liquid outlet 9. The cross-sectional area of the third liquid outlet 13 is larger than the cross-sectional area of the first liquid outlet 9. The third liquid outlet 13 is located on the outer ring of the flow-guiding element 7.

[0036] Positioning the baffle cap 10 and the first liquid outlet 9 at the same angle will guide the plating solution in the same direction. This uniform flow significantly improves the uniformity of the entire surface of the wafer 5. The design of the third liquid outlet 13 located on the outer ring of the flow guide element 7 can offset the negative impact of the back area of the baffle cap 10 on the flow field.

[0037] In the above embodiment, the baffle cap 10 is in the shape of a dome shell, and the inner side wall of the baffle cap opposite to the first liquid outlet 9 is configured as an arc surface. The shape of the first liquid outlet 9 is configured as a circle, ellipse, U-shape or rectangle.

[0038] For wafers 5 with a faster electroplating speed, the liquid output from the first liquid outlet 9 can be greatly increased by changing the shape and size of the first liquid outlet 9 and the baffle cap 10 .

[0039] like Figure 7As shown, in other embodiments, a baffle bar 14 can be separately provided on the flow guide element 7. The baffle bar 14 can also guide the electroplating solution to have a uniform tilt direction. The baffle bar 14 of the flow guide element 7 can be linked to an external mechanical device, and its baffle angle can be adjusted during the electroplating process based on the real-time electroplating status. For example, a motor or cylinder can be provided, and the baffle bar 14 can be hinged to the flow guide element 7. The motor or cylinder can then drive the baffle bar 14 to rotate in real time to adjust the baffle angle.

[0040] In some embodiments, the first liquid outlets 9 are only located at certain positions, such as the center of the wafer 5 or at positions where the ion concentration of the plating solution needs to be replenished. That is, the number and position of the first liquid outlets 9 of the flow-guiding element 7 can be adjusted according to actual needs.

[0041] 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. Wafer electroplating equipment, including: An electroplating chamber (1) is provided with a first liquid inlet (2) and a second liquid inlet (3); a rotating assembly (4) for clamping and rotating the wafer (5) so that the lower surface of the wafer (5) contacts the electroplating solution in the electroplating chamber (1); A flow-guiding element (7), comprising a connected cavity (17), a third liquid inlet (8) and at least one first liquid outlet (9); characterized in that: at least one of the first liquid outlets (9) is provided with a flow-blocking device, the flow-blocking device being used to control the flow direction of the electroplating liquid passing through the first liquid outlet (9); and the flow-guiding element (7) is also provided with a through hole (11), the through hole (11) being arranged to penetrate the flow-guiding element (7).

2. The wafer electroplating equipment according to claim 1, wherein: The flow blocking device comprises a flow blocking cap (10) and / or a flow blocking strip (14).

3. The wafer electroplating equipment according to claim 2, wherein: The angle between the baffle cap (10) on the first liquid outlet (9) and the first liquid outlet (9) is in a clockwise or counterclockwise spiral distribution.

4. The wafer electroplating equipment according to claim 3, wherein: A second liquid outlet (12) is provided on the flow-guiding element (7), and the cross-sectional area of the second liquid outlet (12) is greater than the cross-sectional area of the first liquid outlet (9).

5. The wafer electroplating equipment according to claim 2, wherein: The angle direction of the baffle cap (10) and the first liquid outlet (9) is arranged to face the same side, and the guide element (7) is provided with a third liquid outlet (13) on a side facing away from the angle direction of the baffle cap (10) and the first liquid outlet (9), and the cross-sectional area of the third liquid outlet (13) is greater than the cross-sectional area of the first liquid outlet (9).

6. The wafer electroplating equipment according to any one of claims 2 to 5, characterized in that: The baffle cap (10) is in the shape of a shell with a dome as a whole, and the inner side wall of the guide cap opposite to the first liquid outlet (9) is configured as an arc surface.

7. The wafer electroplating equipment according to claim 2, wherein: The first liquid outlet (9) and the through hole (11) are cross-distributed on the flow-guiding element (7).

8. The wafer electroplating equipment according to claim 6, wherein: The shape of the first liquid outlet (9) is set to be circular, elliptical, U-shaped or rectangular.

9. The wafer electroplating equipment according to claim 1, wherein: The third liquid inlet (8) is arranged on the side wall of the flow guiding element (7).

10. The wafer electroplating equipment according to claim 1, wherein: The rotating assembly (4) comprises a round 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 round cup (101), and the support rod (103) sequentially connects the top plate (104), the conical portion (102) and the round cup (101).

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