Substrate treatment method

Abstract

Provided in the present invention is a substrate treatment method, comprising: keeping a substrate tilted relative to the liquid surface of an electroplating solution; moving the substrate vertically downward, such that the substrate is in contact with the electroplating solution; and laying the substrate flat, and immersing same in the electroplating solution. In the substrate treatment method of the present invention, during the process of immersing the substrate in the electroplating solution, the substrate is tilted relative to the liquid surface of the electroplating solution to allow bubbles to escape along the inclined substrate surface; moreover, not rotating the substrate can prevent the corners of the substrate from agitating the electroplating solution, and rotating the substrate at a predetermined speed helps to expel, in the process of immersing the substrate in the electroplating solution, bubbles adhering to the substrate surface, thereby ensuring uniform electroplating thickness on the substrate surface and improving the product yield.

Description

Substrate processing method

[0001] This application claims priority to Chinese Patent Application No. 202410856154.4, filed on June 27, 2024, the contents of which are incorporated herein by reference in their entirety. TECHNICAL FIELD

[0002] The present application belongs to the technical field of semiconductor, and relates to a substrate processing method. BACKGROUND

[0003] Generally, in a semiconductor wafer (hereinafter referred to as a substrate) electroplating process, an electroplating solution forms a metal film on the surface of the substrate.

[0004] There are many factors that affect the quality of the electroplating process. In particular, during the process of immersing the substrate in the electroplating solution, bubbles can adhere to the surface of the substrate, causing the area adhered by the bubbles to be unable to be exposed to the electroplating solution, thereby resulting in electroplating defects. The electroplating defects can manifest as no electroplating or reduced thickness of the plated layer, depending on the time the bubbles stay on the substrate. Generally, a circular substrate (also known as a wafer) is rotated during immersion in the electroplating solution with a rotation axis perpendicular to the substrate, which helps to remove the bubbles on the surface of the substrate by centrifugal force. However, for a square substrate, rotating the substrate during immersion in the electroplating solution stirs the electroplating solution, causing more bubbles in the electroplating solution. Therefore, the square substrate cannot be rotated during immersion in the electroplating solution, but without rotation, the bubbles on the surface of the substrate cannot be removed.

[0005] Therefore, it has become one of the urgent technical problems for those skilled in the art to provide a method for reducing bubbles on the surface of a substrate during immersion in an electroplating solution, ensuring uniform thickness of electroplating on the surface of the substrate, and improving product yield.

[0006] Therefore, in view of the above-mentioned problems of the prior art, the present application is developed by the inventor of the present application based on years of experience in the field, and actively studies and improves the prior art, thereby providing a method for immersing a substrate in an electroplating solution. SUMMARY

[0007] In view of the above-mentioned problems of the prior art, the present application is developed by the inventor of the present application based on years of experience in the field, and actively studies and improves the prior art, thereby providing a method for immersing a substrate in an electroplating solution.

[0008] To achieve the above-mentioned objects and other related objects, the present application provides a substrate processing method, which comprises: keeping a substrate inclined relative to the liquid surface of an electroplating solution; moving the substrate vertically downward so that the substrate contacts the electroplating solution; and flattening the substrate to immerse the substrate in the electroplating solution. Optionally, the step of flattening the substrate to immerse the substrate in the electroplating solution comprises: after the substrate contacts the electroplating solution, continuing to move the substrate vertically downward while flattening the substrate.

[0009] Optionally, the step of placing the substrate flat and immersing the substrate in the electroplating solution comprises: after the substrate contacts the electroplating solution, stopping moving the substrate vertically downward, and placing the substrate flat to immerse the substrate in the electroplating solution.

[0010] To achieve the above object and other related objects, the present application also provides a substrate processing method, which comprises: keeping a substrate inclined at a predetermined angle relative to a liquid surface of an electroplating solution; moving the substrate vertically downward to make the substrate contact the electroplating solution; keeping the angle of the substrate relative to the liquid surface of the electroplating solution unchanged, and moving the substrate vertically downward until the substrate is completely immersed in the electroplating solution.

[0011] Optionally, the substrate keeps non-rotating from the time when the substrate contacts the liquid surface of the electroplating solution to the time when the substrate is completely immersed in the electroplating solution.

[0012] To achieve the above object and other related objects, the present application also provides a substrate processing method, which comprises: keeping a substrate inclined at a predetermined angle relative to a liquid surface of an electroplating solution; moving the substrate vertically downward to make the substrate contact the electroplating solution; rotating the substrate at a predetermined speed, moving the substrate vertically downward and completely immersing the substrate in the electroplating solution, wherein, when a seed layer on the substrate has a first thickness, the substrate is rotated at a first rotating speed; when the seed layer on the substrate has a second thickness, the substrate is rotated at a second rotating speed; the first thickness is smaller than the second thickness, and the first rotating speed is smaller than the second rotating speed.

[0013] Optionally, the predetermined angle is between 0° and 10°.

[0014] Optionally, while the substrate is rotating, the substrate is placed flat while being moved vertically downward.

[0015] Optionally, while the substrate is rotating, the substrate is moved vertically downward to a predetermined distance below the liquid surface of the electroplating solution, then the moving of the substrate vertically downward is stopped, and the substrate is placed flat.

[0016] Optionally, when the seed layer on the substrate has a first thickness, during the rotation of the substrate, a wetted area of the substrate in the electroplating solution becomes larger and larger, and the rising speed of the wetted area under the action of the rotation of the substrate is smaller than the moving speed of the substrate vertically downward to keep the wetted area always immersed in the electroplating solution.

[0017] Optionally, when the substrate is moved vertically downward, any edge of the substrate first contacts the electroplating solution.

[0018] Optionally, the first corner of the substrate contacts the plating solution first when the substrate is moved vertically downward.

[0019] Optionally, the substrate is tilted relative to the surface of the plating solution, and the angle at which the substrate is tilted relative to the surface of the plating solution is 5° to 10°.

[0020] Optionally, the first rotation speed is less than 5 rpm.

[0021] Optionally, the second rotation speed is between 80 rpm and 100 rpm.

[0022] As described above, the substrate processing method of the present application, in which the substrate is tilted relative to the surface of the plating solution during the process of immersing the substrate into the plating solution to allow the bubbles to escape along the tilted surface of the substrate, and in which the substrate is not rotated to prevent the corner of the substrate from stirring the plating solution, and in which the substrate is rotated at a predetermined speed to help expel the bubbles attached to the surface of the substrate when the substrate is immersed into the plating solution, ensures the uniformity of the plating thickness on the surface of the substrate and improves the yield of products.

[0023] SUMMARY

[0024] The features and advantages of the present application are further described by the following examples and figures.

[0025] FIG. 1 is a schematic diagram of the substrate being tilted relative to the surface of the plating solution according to the present application.

[0026] FIG. 2 is a schematic diagram of the substrate just contacting the surface of the plating solution according to the present application.

[0027] FIG. 3 is a schematic diagram of one embodiment of the method of immersing the substrate into the plating solution according to the present application.

[0028] FIG. 4 is a schematic diagram of another embodiment of the method of immersing the substrate into the plating solution according to the present application.

[0029] FIG. 5 is a schematic diagram of another embodiment of the method of immersing the substrate into the plating solution according to the present application.

[0030] FIG. 6 is an effect diagram of the plating film after the substrate is immersed into the plating solution without rotating the substrate according to the present application.

[0031] FIG. 7 is an effect diagram of the plating film after the substrate is immersed into the plating solution with rotating the substrate according to the present application.

[0032] PREFERRED EMBODIMENTS OF THE PRESENT INVENTION

[0033] Following, the advantages and effects of the present application will be described in detail by specific examples, and other advantages and effects of the present application can be easily understood by those skilled in the art from the disclosure of this specification. The present application can also be implemented or applied by other different specific embodiments, and the details in this specification can be modified or changed based on different views and applications without departing from the spirit of the present application.

[0034] As described in the detailed description of the embodiments of the present application, the cross-sectional views showing the structure of the device are partially enlarged without the general scale for the convenience of explanation, and the schematic views are only examples which should not limit the scope of protection of the present application. In addition, the three-dimensional spatial dimensions including length, width and depth should be included in the actual fabrication.

[0035] For the convenience of description, spatial relationship words such as "under", "below", "lower", "lower than", "underneath", "above", "upper", "on", etc. can be used herein to describe the relationship of one element or feature to other elements or features shown in the drawings. It will be understood that these spatial relationship words are intended to include other directions of the device in use or operation in addition to the directions depicted in the drawings. In addition, when a layer is referred to as "between" two layers, it can be the only layer between the two layers, or one or more intervening layers can also be present. "Between" is used herein to include both end point values.

[0036] In the context of the present application, the structure described as the first feature "on" the second feature can include the embodiment in which the first and second features are formed in direct contact, and can also include the embodiment in which another feature is formed between the first and second features, so that the first and second features can not be in direct contact.

[0037] It should be noted that the diagrams provided in the embodiments only schematically illustrate the basic concepts of the present application, and only the components related to the present application are shown in the diagrams, not the number, shape and size of the components when actually implemented. The actual implementation of each component can be a random change, and the component layout pattern can be more complex.

[0038] Referring to FIG. 1, during the substrate plating process, the substrate W needs to be immersed in the plating solution 2 in the plating cavity 1 to form a metal film on the surface of the substrate W. As mentioned above, during the immersion of the square substrate in the plating solution, the rotation around the rotation axis A perpendicular to the substrate will cause too much agitation of the substrate corners to the plating solution, resulting in more bubbles in the plating solution. Therefore, in some embodiments, the substrate is kept from rotating during the immersion of the substrate in the plating solution, thereby avoiding the generation of bubbles due to agitation. On the other hand, due to the non-rotation of the substrate, the bubbles present in the middle and edges of the substrate cannot be discharged, and with the rotation of the substrate during the plating of the film, the bubbles will move back and forth on the surface of the substrate. The thickness distribution of the substrate after plating is shown in FIG. 6, where the abscissa is the substrate position and the center of the substrate, and the ordinate is the substrate thickness, with the unit of μm. It can be seen that although the film thickness of the edges and the middle of the substrate is thinner, the film thickness uniformity is within the effective range. In order to better discharge the bubbles on the surface of the substrate, the substrate is rotated at a predetermined speed during the immersion of the substrate to discharge the bubbles on the surface of the substrate, and the film after the plating of the substrate is shown in FIG. 7, the bubbles in the middle and edges of the substrate are discharged. For more details, please refer to the description of the following embodiments.

[0039] As shown in FIG. 1, the substrate W is at an angle A with the horizontal plane F, and the horizontal plane F is parallel to the plating solution surface, so the angle between the substrate W and the plating solution surface is also A. Therefore, in the embodiments of the present application, the positioning of the substrate at an angle relative to the horizontal plane is equivalent to the positioning of the substrate at an angle relative to the plating solution surface. Herein, in the embodiments of the present application, during the immersion of the substrate in the plating solution, in order to discharge the bubbles on the surface of the substrate, the substrate is positioned at an angle of 5° to 10° relative to the plating solution surface. In addition, it needs to be explained that the shape of the substrate immersed in the plating solution using the method in the present application is square. Therefore, it can be understood that the square substrate includes four edges and four corners formed by the intersection of two edges. Based on different situations in which the substrate is positioned at an angle relative to the plating solution surface, different embodiments are included. In some embodiments, the substrate is positioned at an angle relative to the plating solution surface, and none of the edges of the substrate is parallel to the plating solution surface, and then one corner of the substrate first contacts the plating solution surface. In other embodiments, the substrate is positioned at an angle relative to the plating solution surface, and one pair of opposite edges of the substrate is parallel to the plating solution surface, and then one edge of the substrate first contacts the plating solution surface.

[0040] Embodiment one:

[0041] Referring to the embodiment shown in FIG. 3, in the present embodiment, the substrate is kept from rotating, and the substrate processing method comprises:

[0042] S11: keeping the substrate at an angle relative to the plating solution surface;

[0043] In this step, the substrate is positioned at an angle relative to the plating solution surface and kept at the same angle.

[0044] S12: vertically moving the substrate downward to contact the plating solution;

[0045] As shown in FIG. 2, the substrate W is vertically moved downward to just contact the surface of the plating solution 2, and then continues to move downward.

[0046] S13: placing the substrate horizontally to immerse the substrate in the plating solution.

[0047] In some embodiments, in step S12, the substrate has been moved vertically downward to a first distance below the surface of the plating solution, so that when the substrate is placed horizontally, the substrate does not move vertically downward, and the substrate can be completely immersed in the plating solution. In other embodiments, after the substrate is moved vertically downward to contact the plating solution in step S12, the substrate continues to move vertically downward while the substrate is placed horizontally.

[0048] In this embodiment, the substrate does not rotate, which can avoid the generation of bubbles due to agitation. Meanwhile, the substrate is inclined relative to the surface of the plating solution, which can also help the bubbles to be naturally discharged. The thickness of the final electroplated film can meet the uniformity requirement.

[0049] Embodiment Two:

[0050] Referring to the embodiment shown in FIG. 4, in this embodiment, the substrate is kept from rotating, and the substrate processing method comprises:

[0051] S21: keeping the substrate inclined relative to the surface of the plating solution;

[0052] In this step, the substrate is positioned to be inclined relative to the surface of the plating solution and the inclination angle is kept unchanged.

[0053] S22: vertically moving the substrate downward to contact the plating solution;

[0054] As shown in FIG. 2, the substrate W is vertically moved downward to just contact the surface of the plating solution 2, and then continues to move downward.

[0055] S23: keeping the angle of the substrate relative to the surface of the plating solution unchanged, and vertically moving the substrate downward until the substrate is completely immersed in the plating solution.

[0056] In this embodiment, the substrate does not rotate, which can avoid the generation of bubbles due to agitation. Meanwhile, the substrate is inclined relative to the surface of the plating solution, which can also help the bubbles to be naturally discharged. The thickness of the final electroplated film can meet the uniformity requirement.

[0057] Embodiment Three:

[0058] Referring to the embodiment shown in FIG. 5, in this embodiment, the substrate processing method comprises:

[0059] S31: keep the substrate inclined relative to the plating solution surface;

[0060] In this step, the substrate is positioned to be inclined relative to the plating solution surface and the inclination angle is kept unchanged.

[0061] S32: move the substrate vertically downward to contact the plating solution;

[0062] As shown in Fig. 2, the substrate W is moved vertically downward to just contact the surface of the plating solution 2, and then the substrate is continuously moved vertically downward.

[0063] S33: rotate the substrate at a predetermined speed when the substrate contacts the surface, move the substrate vertically downward, and immerse the substrate completely in the plating solution.

[0064] In this embodiment, the substrate is rotated at a predetermined speed instead of a high rotation speed, so that the bubbles generated by agitation can be reduced as much as possible. Meanwhile, the substrate is inclined relative to the plating solution surface, and the rotation at a predetermined speed can also help the bubbles to be discharged. The thickness of the final electroplated film can meet the uniformity requirement.

[0065] In this step, in some embodiments, the substrate is continuously moved vertically downward to a predetermined distance below the plating solution surface in step S33, so that the substrate can be completely immersed in the plating solution when the substrate is leveled without being moved vertically downward. Then the vertical downward movement of the substrate is stopped, and the substrate is leveled. In other embodiments, the substrate is moved vertically downward to contact the plating solution in step S32, and the substrate is continuously moved vertically downward while being leveled.

[0066] In step S33, the substrate is rotated at a first rotation speed when the thickness of the seed layer on the substrate surface is a first thickness.

[0067] In step S33, the substrate is rotated at a second rotation speed when the thickness of the seed layer on the substrate surface is a second thickness.

[0068] The first thickness is less than the second thickness, and the first rotation speed is less than the second rotation speed. During the substrate being immersed in the electroplating solution, the substrate is kept rotating to expel the bubbles on the surface of the substrate. During the process of the substrate being immersed in the electroplating solution (hereinafter referred to as the process of the substrate being immersed in the electroplating solution), the substrate is easy to turn the area of the substrate which has been wetted by the electroplating solution out of the electroplating solution when the substrate is rotating, resulting in that the area of the substrate which is out of the electroplating solution has no voltage protection, and thus the seed layer of the area is completely or partially corroded by the residual electroplating solution. If the thickness of the seed layer on the surface of the substrate is too thin, the area of the substrate can not be electroplated to form a metal film due to the corrosion. In order to better ensure that the wetted area of the substrate is not turned out of the electroplating solution, the substrate first contacts the electroplating solution at the angle. Therefore, when the thickness of the seed layer on the surface of the substrate is the first thickness, the substrate is kept rotating during the process of the substrate being immersed in the electroplating solution, and the wetted area of the substrate being immersed in the electroplating solution is getting larger and larger. Under the action of the rotation of the substrate, the rising speed of the wetted area is less than the speed of the substrate moving vertically downward to keep the wetted area immersed in the electroplating solution. And the rising speed of the wetted area of the substrate under the action of the rotation of the substrate is obtained according to the rotation speed of the substrate. Since the rotation speed of the substrate is different, the rising speed of the wetted area of the substrate is also different, and thus the rising speed of the wetted area of the substrate under the action of the rotation of the substrate can be obtained according to the rotation speed of the substrate. At this time, the rotation speed of the substrate is the first rotation speed. Since the rotation speed of the substrate is very slow, the rotation of the substrate can limit the angle of the substrate to generate too much agitation to the electroplating solution and form bubbles on the lower surface of the substrate, and the rotation of the substrate can also help to expel the bubbles on the lower surface of the substrate. Generally, the first rotation speed is less than 5 rpm. When the thickness of the seed layer on the surface of the substrate is the second thickness (the second thickness is greater than the first thickness), the substrate is rotated to turn the area of the substrate which has been wetted by the electroplating solution out of the electroplating solution during the process of the substrate being immersed in the electroplating solution. Since the seed layer has a certain thickness at this time, the wetted area can be corroded by the residual electroplating solution, but it will not be completely corroded in the thickness direction, and thus the high-speed rotation of the substrate will not affect the electroplating of the substrate to form a metal film when the wetted area is turned out of the electroplating solution. In order to help to expel the bubbles on the surface of the substrate, the rotation speed of the substrate is increased when the thickness of the seed layer on the surface of the substrate is the second thickness. At this time, the rotation speed of the substrate is the second rotation speed, and the second rotation speed is higher than the first rotation speed. The substrate has more bubbles at the second rotation speed, but the centrifugal force generated at the second rotation speed helps to expel more bubbles. Generally, the second rotation speed is 80 rpm-100 rpm. It should be pointed out that the predetermined angle obtained by tilting the substrate relative to the liquid level of the electroplating solution is generally between 0° and 10°. The greater the predetermined angle obtained by tilting the substrate relative to the liquid level of the electroplating solution, the more helpful it is to expel the bubbles on the surface of the substrate. Therefore, more preferably, the predetermined angle obtained by tilting the substrate relative to the liquid level of the electroplating solution is 5° to 10°. Generally, when the second thickness is greater than 20 angstroms, the wetted area of the substrate being turned out of the electroplating solution will not affect the electroplating effect, and the first thickness is less than or equal to 20 angstroms.

[0069] In summary, the method of the present application, the substrate does not rotate to prevent the corner of the substrate agitating the plating solution, and the substrate rotates at a predetermined speed to help expel the bubbles attached to the surface of the substrate when the substrate is immersed in the plating solution, ensuring the uniformity of the plating thickness on the surface of the substrate, and improving the yield of the product.

[0070] The above embodiments are only illustrative of the principles and effects of the present application, and are not intended to limit the present application. Any person skilled in the art can modify or change the above embodiments without departing from the spirit and scope of the present application. Therefore, all equivalent modifications or changes made by those skilled in the art without departing from the spirit and technical ideas disclosed by the present application should be covered by the claims of the present application.

Claims

1. A substrate processing method characterized by, include: Keep the substrate tilted relative to the surface of the electroplating solution; The substrate is moved vertically downwards to bring it into contact with the electroplating solution; Lay the substrate flat and immerse it in the electroplating solution.

2. The substrate processing method according to claim 1, wherein The step of flattening the substrate and immersing the substrate in the electroplating solution includes: after the substrate contacts the electroplating solution, the substrate is flattened while continuing to move it vertically downward.

3. The substrate processing method according to claim 1, wherein The step of flattening the substrate and immersing the substrate in the electroplating solution includes: after the substrate comes into contact with the electroplating solution, stopping the vertical downward movement of the substrate, and flattening the substrate to immerse the substrate in the electroplating solution.

4. A substrate processing method characterized by, include: Keep the substrate tilted relative to the surface of the electroplating solution; The substrate is moved vertically downwards to bring it into contact with the electroplating solution; Keeping the angle between the substrate and the surface of the electroplating solution unchanged, move the substrate vertically downwards until the substrate is completely immersed in the electroplating solution.

5. The substrate processing method according to any one of claims 1 to 4, wherein From the moment the substrate comes into contact with the surface of the electroplating solution until the substrate is completely immersed in the electroplating solution, the substrate remains stationary and does not rotate.

6. A substrate processing method characterized by, include: Maintain the substrate at a predetermined angle relative to the surface of the electroplating solution; The substrate is moved vertically downwards so that it comes into contact with the electroplating solution; The substrate is rotated at a predetermined speed, moved vertically downwards, and completely immersed in the electroplating solution. Wherein, when the thickness of the seed layer on the substrate surface is a first thickness, the substrate is rotated at a first rotation speed; When the seed layer thickness on the substrate surface is a second thickness, the substrate is rotated at a second rotation speed; The first thickness is less than the second thickness, and the first rotational speed is less than the second rotational speed.

7. The substrate processing method according to claim 6, wherein the predetermined angle is between 0° and 10°.

8. The substrate processing method according to claim 6, wherein While the substrate is rotating, the substrate is moved vertically downwards and laid flat.

9. The substrate processing method according to claim 6, wherein When the substrate is rotated, the substrate is moved vertically downwards to a predetermined distance below the surface of the electroplating solution, then the vertical downward movement of the substrate is stopped, and the substrate is laid flat.

10. The substrate processing method according to claim 6, wherein When the seed layer thickness on the substrate surface is a first thickness, during the rotation of the substrate, the wetted area of ​​the substrate immersed in the electroplating solution becomes larger and larger. Under the rotation of the substrate, the rising speed of the wetted area is less than the vertical downward speed of the substrate, so that the wetted area is always immersed in the electroplating solution.

11. The substrate processing method according to claim 1 or 4, wherein When the substrate is moved vertically downwards, any edge of the substrate will first come into contact with the electroplating solution.

12. The substrate processing method according to any one of claims 1, 4, and 6, wherein When the substrate is moved vertically downwards, any corner of the substrate will come into contact with the electroplating solution first.

13. The substrate processing method according to any one of claims 1, 4, and 6, wherein The substrate is tilted relative to the surface of the electroplating solution, such that the angle of tilt between the substrate and the surface of the electroplating solution is 5° to 10°.

14. The substrate processing method according to claim 6, wherein The first rotational speed is less than 5 rpm.

15. The substrate processing method as set forth in claim 6, wherein The second speed is between 80 rpm and 100 rpm.

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