Electroplating method of through hole and semiconductor structure

Abstract

The invention provides a through hole electroplating method and a semiconductor structure, and the method comprises the steps: providing a substrate, forming at least one through hole in the substrate, forming a metal seed layer on the inner surface of the through hole, and processing the metal seed layer through nanosecond laser, so as to increase the roughness of the surface of the metal seed layer. The hydrophilicity of the surface of the rough metal seed layer is better, the substrate is immersed in an electroplating solution, the substrate is electroplated, and an electroplated metal layer is formed on the surface of the metal seed layer; wherein in the process of immersing the substrate into the electroplating solution, the surface, with the opening of the through hole, of the substrate faces the electroplating solution, so that the substrate moves towards the electroplating solution sequentially based on a first preset speed, a second preset speed and a third preset speed; the first preset speed and the third preset speed are respectively higher than the second preset speed, and the discharging speed of air in the through hole can be improved by enabling the substrate to enter water at high, slow and high speeds, so that the quality of an electroplated metal layer is improved.

Description

Technical Field

[0001] This invention relates to the field of semiconductors, and in particular to a method for electroplating through-holes and a semiconductor structure. Background Technology

[0002] In the semiconductor field, with the continuous improvement of chip integration and the continuous shrinking of feature size, multilayer interconnect structures have become one of the core architectures for device manufacturing. Vias, trenches, and other structures are key units of multilayer interconnect structures, and their conductivity and structure directly determine device performance.

[0003] However, during the electroplating of vias and trenches, the wafer is often immersed in the plating solution face down, with the openings of the vias and trenches also facing downwards. This causes air bubbles to remain inside the vias and trenches. Due to the lack of effective venting methods, electroplating begins before all the bubbles are completely expelled, resulting in insufficient density of the deposited metal layer. During subsequent packaging or use, the metal layer on the surface of the vias and trenches is susceptible to thermal stress and fracture, reducing the reliability of the semiconductor device.

[0004] It should be noted that the above introduction to the technical background is only for the purpose of providing a clear and complete explanation of the technical solutions of this application and facilitating understanding by those skilled in the art. It should not be assumed that these technical solutions are known to those skilled in the art simply because they have been described in the background section of this application. Summary of the Invention

[0005] In view of the shortcomings of the prior art described above, the purpose of this invention is to provide a method for electroplating through holes and a semiconductor structure to solve the problem that the internal air of through holes and trenches cannot be completely discharged during the electroplating process, thus affecting the density of the electroplated metal layer.

[0006] To achieve the above and other related objectives, the present invention provides an electroplating method for through holes, the method comprising:

[0007] A substrate is provided, wherein at least one through-hole is formed therein; wherein at least one opening of the through-hole is located on the surface of the substrate;

[0008] A metal seed layer is formed on the inner surface of the through hole;

[0009] The metal seed layer is treated with a nanosecond laser to increase the surface roughness of the metal seed layer;

[0010] The substrate is immersed in an electroplating solution and electroplated to form an electroplated metal layer on the surface of the metal seed layer.

[0011] During the process of immersing the substrate in the electroplating solution, the side of the substrate with the opening of the through hole faces the electroplating solution, so that the substrate moves toward the electroplating solution sequentially at a first preset speed, a second preset speed, and a third preset speed; the first preset speed and the third preset speed are respectively greater than the second preset speed.

[0012] In one embodiment, the average laser power of the nanosecond laser processing is 50W-100W; the laser pulse wavelength of the nanosecond laser processing is 1064nm.

[0013] In one embodiment, the laser displacement step size of the nanosecond laser processing is less than or equal to the laser spot radius.

[0014] In one embodiment, the first preset speed and the third preset speed are 200mm / s-300mm / s; the second preset speed is 50mm / s-100mm / s.

[0015] In one embodiment, the processing time for the first preset speed and the third preset speed is 0.4s-2s; the processing time for the second preset speed is 0.1s-0.5s.

[0016] In one embodiment, the angle between the side of the substrate having the opening of the through hole and the surface of the electroplating solution is 2-5 degrees.

[0017] In one embodiment, the material of the metal seed layer is Ti, TaN, or Cu.

[0018] In one embodiment, the electroplating solution is a copper-containing solution.

[0019] In one embodiment, during the process of immersing the substrate in the electroplating solution, the substrate is rotated at a preset rotation speed; the preset rotation speed is 400 rpm-600 rpm.

[0020] Secondly, this application also provides a semiconductor structure, which is prepared by the electroplating method for through holes as described in any one of the embodiments of this application.

[0021] As described above, the electroplating method for through-holes and the semiconductor structure of the present invention have the following beneficial effects:

[0022] The electroplating method and semiconductor structure for through-holes of the present invention involve providing a substrate in which at least one through-hole is formed, with at least one opening of the through-hole located on the surface of the substrate. A metal seed layer is formed on the inner surface of the through-hole to enhance the adhesion and uniformity of the thick electroplated metal layer and improve its quality. The metal seed layer is then treated with a nanosecond laser to increase its surface roughness. Compared to a smooth surface, a rougher metal seed layer has better hydrophilicity, allowing for rapid air removal from the through-hole. The substrate is then immersed in an electroplating solution and electroplated to form an electroplated metal layer on the surface of the metal seed layer. During the immersion process, the side of the substrate with the through-hole opening faces the electroplating solution, and the substrate is moved toward the solution sequentially at a first preset speed, a second preset speed, and a third preset speed. The first and third preset speeds are respectively greater than the second preset speed. By immersing the substrate in water at fast, slow, and fast speeds, the air removal rate from the through-hole can be increased, further preventing air residue inside the through-hole and thus improving the quality of the electroplated metal layer. Attached Figure Description

[0023] The accompanying drawings, which form part of this specification, are used to provide a further understanding of the embodiments of this application and to illustrate the implementation of this application, together with the textual description, to explain the principles of this application. Obviously, the drawings described below are merely some embodiments of this application.

[0024] Figure 1 The diagram shows a flow chart of a through-hole electroplating method provided in one embodiment of this application.

[0025] Figure 2 The image shown is a topographic scanning diagram of the surface of a metal seed layer provided in one embodiment of this application. Detailed Implementation

[0026] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0027] It should be emphasized that the term "including / comprises" as used herein refers to the presence of a feature, whole, step, or component, but does not exclude the presence or addition of one or more other features, wholes, steps, or components.

[0028] Features described and / or illustrated for one embodiment may be used in the same or similar manner in one or more other embodiments, combined with features in other embodiments, or substituted for features in other embodiments.

[0029] In the detailed description of embodiments of the present invention, for ease of explanation, the cross-sectional views illustrating the device structure may be partially enlarged and not to scale. Furthermore, the schematic diagrams are merely examples and should not limit the scope of protection of the present invention. In actual fabrication, the three-dimensional spatial dimensions of length, width, and depth should be included.

[0030] For ease of description, spatial relation terms such as “below,” “under,” “lower than,” “below,” “above,” and “upper” may be used herein to describe the relationship between one element or feature shown in the accompanying drawings and other elements or features. It will be understood that these spatial relation terms are intended to include directions other than those depicted in the drawings for devices in use or operation. Furthermore, when a layer is referred to as being “between” two layers, it may be the only layer between the two layers, or there may be one or more layers in between.

[0031] In the context of this application, the structure described above the first feature may include embodiments in which the first and second features are formed in direct contact, or embodiments in which additional features are formed between the first and second features, such that the first and second features may not be in direct contact.

[0032] It should be noted that the illustrations provided in this embodiment are only schematic representations of the basic concept of the present invention. Therefore, the illustrations only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0033] For the reasons mentioned above, please refer to Figure 1 This application provides an electroplating method for through holes, including steps S102-S108.

[0034] Step S102: Provide a substrate, wherein at least one through hole is formed in the substrate; wherein at least one opening of the through hole is located on the surface of the substrate.

[0035] As an example, the substrate may also include other components, such as diodes, transistors, and capacitors. This application does not impose specific limitations on the type or structure of other components within the substrate.

[0036] As an example, the substrate material may include silicon (Si), silicon germanium (SiGe), silicon germanium carbon (SiGeC), silicon carbide (SiC), gallium arsenide (GaAs), indium arsenide (InAs), indium phosphide (InP), or other III / V or II / VI semiconductor materials. This application does not impose specific limitations on the substrate material.

[0037] As an example, the through-hole extends within the substrate along the thickness direction of the substrate. At least one opening of the through-hole is located on the substrate surface, and the other opening may also be located on the substrate surface, i.e., the through-hole penetrates the substrate along the thickness direction; alternatively, the other opening of the through-hole is located inside the substrate. This application does not impose specific limitations on the structure or size of the through-hole.

[0038] Step S104: Form a metal seed layer on the inner surface of the through hole.

[0039] As an example, a metal seed layer can be formed on the inner surface of a through-hole using methods such as physical vapor deposition, chemical vapor deposition, and atomic layer deposition.

[0040] Step S106: Use a nanosecond laser to process the metal seed layer to increase the surface roughness of the metal seed layer.

[0041] Please refer to Figure 2 In this process, nanosecond lasers are used to treat the metal seed layer, causing the material on the surface of the metal seed layer to ablate and then fall onto the surface of the metal seed layer and solidify, forming micro-hills or nanoparticles on the surface of the metal seed layer. This increases the roughness of the surface of the metal seed layer, thereby enhancing the hydrophilicity of the metal seed layer.

[0042] Step S108: Immerse the substrate in the electroplating solution and electroplat the substrate to form an electroplated metal layer on the surface of the metal seed layer; wherein, during the process of immersing the substrate in the electroplating solution, the side of the substrate with the through hole faces the electroplating solution, so that the substrate moves toward the electroplating solution sequentially at a first preset speed, a second preset speed and a third preset speed; the first preset speed and the third preset speed are respectively greater than the second preset speed.

[0043] As an example, those skilled in the art can set the current and voltage parameters for electroplating as needed, and the embodiments of this application do not impose specific limitations on this.

[0044] As an example, the side of the substrate with the through-hole opening may be parallel to the surface of the electroplating solution, or the side of the substrate with the through-hole opening may have an angle with the surface of the electroplating solution.

[0045] As an example, during the process of immersing the substrate in the electroplating solution, the substrate is moved toward the electroplating solution sequentially at a first preset speed, a second preset speed, and a third preset speed. That is, the substrate approaches the electroplating solution at the first preset speed, and the time of moving at the first preset speed is the first time. Then, it approaches the electroplating solution or is immersed in the electroplating solution at the second preset speed, and the time of moving at the second preset speed is the second time. Finally, it approaches the electroplating solution or is immersed in the electroplating solution at the third preset speed, and the time of moving at the third preset speed is the third time. After the first time, the second time, and the third time, the through holes in the substrate are completely immersed in the electroplating solution.

[0046] In the above embodiments, a substrate is provided, in which at least one through-hole is formed. At least one opening of the through-hole is located on the surface of the substrate, and a metal seed layer is formed on the inner surface of the through-hole, thereby enhancing the adhesion and uniformity of the thick electroplated metal layer and improving the quality of the electroplated metal layer. Then, the metal seed layer is treated with a nanosecond laser to increase the surface roughness of the metal seed layer. Compared with a smooth plane, the rougher surface of the metal seed layer has better hydrophilicity, so as to quickly expel the air in the through-hole. The substrate is then immersed in an electroplating solution and electroplated to form an electroplated metal layer on the surface of the metal seed layer. During the process of immersing the substrate in the electroplating solution, the side of the substrate with the opening of the through-hole faces the electroplating solution, and the substrate moves toward the electroplating solution sequentially at a first preset speed, a second preset speed, and a third preset speed. The first preset speed and the third preset speed are respectively greater than the second preset speed. By immersing the substrate in water at a fast, slow, and fast speed, the air expulsion speed in the through-hole can be increased, further avoiding air residue inside the through-hole, thereby improving the quality of the electroplated metal layer.

[0047] In some embodiments, the average laser power of nanosecond laser processing is 50W-100W; the laser pulse wavelength of nanosecond laser processing is 1064nm.

[0048] As an example, the average laser power of nanosecond laser processing is 50W, 60W, 70W, 80W, 90W, 100W, etc.

[0049] In the above embodiments, the higher the average laser power, the deeper the laser penetrates into the substrate, and the rougher the surface of the metal seed layer after nanosecond laser treatment will be. However, if the laser penetrates too deeply, it will affect other devices inside the substrate. Therefore, setting the average laser power to 50W-100W can increase the surface roughness without affecting the devices inside the substrate, thereby improving the hydrophilicity of the metal seed layer.

[0050] In some embodiments, the laser displacement step size of nanosecond laser processing is less than or equal to the laser spot radius.

[0051] As an example, the laser displacement step size in nanosecond laser processing is equal to the laser spot radius; or the laser displacement compensation in nanosecond laser processing is equal to 0.4 times the laser spot radius.

[0052] In the above embodiments, by making the laser displacement step size of the nanosecond laser treatment less than or equal to the laser spot radius, the surface of the metal seed layer is ensured to be completely treated by the nanosecond laser, thus avoiding omissions.

[0053] In some embodiments, the first preset speed and the third preset speed are 200mm / s-300mm / s; the second preset speed is 50mm / s-100mm / s.

[0054] As an example, the first preset speed is 200 mm / s, 220 mm / s, 240 mm / s, 260 mm / s, 280 mm / s, 300 mm / s, etc. The second preset speed is 50 mm / s, 60 mm / s, 70 mm / s, 80 mm / s, 90 mm / s, 100 mm / s, etc. The third preset speed is 200 mm / s, 220 mm / s, 240 mm / s, 260 mm / s, 280 mm / s, 300 mm / s, etc.

[0055] In some embodiments, the processing time for the first preset speed and the third preset speed is 0.4s-2s; the processing time for the second preset speed is 0.1s-0.5s.

[0056] For example, the processing times for the first preset speed are 0.4s, 0.6s, 0.8s, 1.0s, 1.2s, 1.4s, 1.6s, 1.8s, and 2.0s, etc. The processing times for the second preset speed are 0.1s, 0.2s, 0.3s, 0.4s, and 0.5s, etc. The processing times for the third preset speed are 0.4s, 0.6s, 0.8s, 1.0s, 1.2s, 1.4s, 1.6s, 1.8s, and 2.0s, etc.

[0057] In some embodiments, during the process of immersing the substrate in the electroplating solution, the substrate is rotated at a preset rotation speed; the preset rotation speed is 400 rpm to 600 rpm.

[0058] As an example, the substrate rotates around the center of the side of the substrate with the through hole opening. The preset speeds are 400 rpm, 450 rpm, 500 rpm, 550 rpm, and 600 rpm.

[0059] In the above embodiments, by making the substrate rotate at a preset speed, centrifugal force is used to expel air bubbles from the through holes, thereby further preventing air bubbles from remaining in the through holes and affecting the quality of the electroplated metal layer.

[0060] In some embodiments, the angle between the side of the substrate with the through-hole opening and the surface of the electroplating solution is 2-5 degrees.

[0061] As an example, the angle between the side of the substrate with the through-hole opening and the surface of the electroplating solution is 2 degrees, 3 degrees, 4 degrees, 5 degrees, etc. Preferably, the angle between the side of the substrate with the through-hole opening and the surface of the electroplating solution is 3 degrees, which can better expel gas from the through-hole.

[0062] In some embodiments, the material of the metal seed layer is Ti, TaN, or Cu.

[0063] In some embodiments, the electroplating solution is a copper-containing solution.

[0064] As an example, the copper-containing solution may include copper sulfate, and the electroplated metal layer is a copper metal layer.

[0065] This application also provides a semiconductor structure, which is prepared by the electroplating method of the through-hole described in any one of the embodiments of this application, comprising: a substrate, a through-hole, a metal seed layer, and an electroplated metal layer; wherein, at least one through-hole is located in the substrate, and at least one opening of the through-hole is located on the surface of the substrate; the metal seed layer covers the inner surface of the through-hole; the metal seed layer is treated with a nanosecond laser; and the electroplated metal layer is located on the surface of the metal seed layer.

[0066] In summary, the electroplating method and semiconductor structure for through-holes of the present invention, by providing a substrate in which at least one through-hole is formed, at least one opening of the through-hole being located on the surface of the substrate, and forming a metal seed layer on the inner surface of the through-hole, thereby enhancing the adhesion and uniformity of the thick electroplated metal layer and improving the quality of the electroplated metal layer, the metal seed layer is then treated with a nanosecond laser to increase the surface roughness of the metal seed layer. Compared to a smooth plane, a rougher metal seed layer surface has better hydrophilicity, so as to quickly expel air from the through-hole. The substrate is then immersed in an electroplating solution and electroplated to form an electroplated metal layer on the surface of the metal seed layer. During the process of immersing the substrate in the electroplating solution, the side of the substrate with the opening of the through-hole faces the electroplating solution, and the substrate is moved toward the electroplating solution sequentially at a first preset speed, a second preset speed, and a third preset speed. The first preset speed and the third preset speed are respectively greater than the second preset speed. By immersing the substrate in water at fast, slow, and fast speeds, the air expulsion rate from the through-hole can be increased, further avoiding air residue inside the through-hole, thereby improving the quality of the electroplated metal layer. Therefore, this invention effectively overcomes the various shortcomings of the prior art and has high industrial application value.

[0067] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A method for electroplating through holes, characterized in that, The method includes: A substrate is provided, wherein at least one through-hole is formed therein; wherein at least one opening of the through-hole is located on the surface of the substrate; A metal seed layer is formed on the inner surface of the through hole; The metal seed layer is treated with a nanosecond laser to increase the surface roughness of the metal seed layer; The substrate is immersed in an electroplating solution and electroplated to form an electroplated metal layer on the surface of the metal seed layer. During the process of immersing the substrate in the electroplating solution, the side of the substrate with the opening of the through hole faces the electroplating solution, so that the substrate moves toward the electroplating solution sequentially at a first preset speed, a second preset speed, and a third preset speed; the first preset speed and the third preset speed are respectively greater than the second preset speed.

2. The electroplating method for through holes according to claim 1, characterized in that, The average laser power of the nanosecond laser processing is 50W-100W; the laser pulse wavelength of the nanosecond laser processing is 1064nm.

3. The electroplating method for through holes according to claim 1, characterized in that, The laser displacement step size of the nanosecond laser processing is less than or equal to the laser spot radius.

4. The electroplating method for through holes according to claim 1, characterized in that, The first preset speed and the third preset speed are 200mm / s-300mm / s; the second preset speed is 50mm / s-100mm / s.

5. The electroplating method for through holes according to claim 4, characterized in that, The processing time for the first preset speed and the third preset speed is 0.4s-2s; the processing time for the second preset speed is 0.1s-0.5s.

6. The electroplating method for through holes according to claim 1, characterized in that, The angle between the side of the substrate with the opening of the through hole and the surface of the electroplating solution is 2-5 degrees.

7. The electroplating method for through holes according to claim 1, characterized in that, The material of the metal seed layer is Ti, TaN or Cu.

8. The electroplating method for through holes according to claim 7, characterized in that, The electroplating solution is a copper-containing solution.

9. The electroplating method for through holes according to claim 1, characterized in that, During the process of immersing the substrate in the electroplating solution, the substrate is made to rotate at a preset speed; the preset speed is 400rpm-600rpm.

10. A semiconductor structure, characterized in that, It is prepared by the electroplating method of any one of claims 1-9 for through holes.

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