Metallization deposition method and system for pore structure

Abstract

The invention relates to the technical field of superconducting quantum computing, and discloses a hole structure metallization deposition method and system, a sacrificial layer is deposited on the surface of a silicon substrate, a hole structure with a preset depth-to-width ratio is etched on a to-be-processed substrate, a substrate with the hole structure is obtained, a first metal material is used for surface deposition of the substrate with the hole structure, and a metallization deposition layer is formed on the surface of the substrate with the hole structure. The preparation method comprises the following steps: forming a hole structure on a substrate, forming a metal induction layer on the surfaces of the substrate and the hole structure to obtain a substrate with the metal induction layer, performing magnetron sputtering on the substrate with the metal induction layer by using a second metal material, and applying a magnetic field around the substrate with the metal induction layer to form a metal film on the surface of the metal induction layer, and obtaining the substrate with the hole structure subjected to metallization deposition. The metal coverage in the holes can be improved by using a metal induction mode, and the deposition uniformity of particles in the holes can be ensured by combining a magnetic field applying mode, so that a deep hole scene can be well dealt with.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of superconducting quantum computing, and in particular to a hole structure metallization deposition method and system. BACKGROUND

[0002] With the continuous reduction of integrated circuit size, it is difficult to meet the requirements in terms of conformality and uniformity of the metal film deposited by using magnetron sputtering technology. For example, with the development of semiconductor technology, the aspect ratio requirement of through-silicon via (TSV) is getting higher and higher, from the original 10:1, to 20:1, and even some semiconductor manufacturers currently have an aspect ratio greater than 20:1. Currently, it is difficult to achieve metal layer deposition with good step coverage in such a high aspect ratio silicon via by using physical vapor deposition (PVD) technology.

[0003] This is because when depositing in a deep hole by using a traditional magnetron sputtering, more than 90% of the sputtering particles (such as Al and Cu) are neutral atoms, which cannot be guided by an electric field, resulting in an effective deposition depth of the existing semiconductor ≤20μm (when the aspect ratio >10:1), and the film thickness at the bottom of the hole is only 28%-35% of the film thickness at the hole opening, and the film thickness uniformity is >10%. In view of this, the existing improvement scheme is limited to the use of atomic layer deposition (ALD) alone, resulting in a dense film layer but a very low deposition rate (deposition rate <10nm / h) and high cost. Although the combination of ion implantation assistance can improve the deposition rate, it is easy to cause lattice damage and is not suitable for the scene of ultra-fine deep hole (hole diameter <5μm).

[0004] Therefore, how to improve the deposition process of a deep hole with a high aspect ratio to improve the sputtering depth while ensuring the film layer coverage and uniformity has become a problem to be solved. SUMMARY

[0005] Embodiments of the present application provide a hole structure metallization deposition method and system to solve the problem of how to improve the deposition process of a deep hole with a high aspect ratio to improve the sputtering depth while ensuring the film layer coverage and uniformity.

[0006] In a first aspect, the present application provides a hole structure metallization deposition method, comprising:

[0007] etching a hole structure with a preset aspect ratio on a substrate to be processed to obtain a substrate with a hole structure;

[0008] depositing a first metal material on the substrate with a hole structure to form a metal-induced layer on the surface of the substrate and the hole structure, and obtaining a substrate with a metal-induced layer;

[0009] A second metal material is used to perform magnetron sputtering on the substrate with the metal induction layer, and a magnetic field is applied around the substrate with the metal induction layer to form a metal film on the surface of the metal induction layer, thereby obtaining a substrate with a pore structure and metallized deposition.

[0010] Optionally, etching a hole structure with a preset aspect ratio on the substrate to be processed to obtain a substrate with the hole structure includes:

[0011] After coating the substrate with adhesive, patterned exposure is performed to obtain the first substrate;

[0012] After etching the first substrate to form a hole structure with a preset aspect ratio, a resist removal cleaning is performed to obtain a substrate with a hole structure.

[0013] Optionally, etching a hole structure with a preset aspect ratio on the substrate to be processed to obtain a substrate with the hole structure includes:

[0014] After depositing a hard mask on the substrate to be processed, a photoresist coating and patterned exposure are performed to obtain a second substrate;

[0015] The second substrate is etched using a hard mask to form a hole structure with a preset aspect ratio. Then, a photoresist removal cleaning is performed to obtain a substrate with a hole structure.

[0016] Optionally, the surface deposition on the substrate having a porous structure includes:

[0017] The substrate with the porous structure is surface-deposited using ALD, CVD, or electroplating methods.

[0018] Optionally, when performing surface deposition on the porous substrate using ALD, the first metal material is copper, copper oxide is used as a precursor, hydrogen is used as a reducing agent, the reaction temperature is 200℃-300℃, and the deposition is performed in 150-300 cycles.

[0019] Optionally, when magnetron sputtering is performed on the substrate with the metal induction layer, the second metal material is aluminum, and magnetron sputtering is performed with a sputtering pressure of 0.1-1 Pa, a pulse voltage of 100-1000 V, a frequency of 50-200 Hz, and a duty cycle of less than 70%.

[0020] In a second aspect, the present invention provides a porous metallization deposition system, the porous metallization deposition system comprising: etching equipment, deposition equipment and magnetron sputtering equipment;

[0021] The etching equipment is used to etch a hole structure with a preset aspect ratio on the substrate to be processed, so as to obtain a substrate with a hole structure.

[0022] The deposition equipment is used to perform surface deposition of a first metal material on the substrate with a porous structure, so that the substrate and the surface of the porous structure have a metal induction layer, thereby obtaining a substrate with a metal induction layer.

[0023] A magnetic field emission module is provided at the sputtering platform inside the chamber of the magnetron sputtering equipment, and the sputtering platform is used to support the substrate with the metal induction layer;

[0024] The magnetron sputtering equipment is used to perform magnetron sputtering on the substrate with the metal induction layer using a second metal material, and to apply a magnetic field around the substrate with the metal induction layer using the magnetic field emission module, so that a metal film is formed on the surface of the metal induction layer, resulting in a substrate with a pore structure and metallized deposition.

[0025] Optionally, the magnetic field emitting module includes at least one induction coil and an alternating power supply, wherein the alternating power supply is connected to all induction coils so that the induction coils generate a magnetic field.

[0026] Optionally, the magnetic field emitting module further includes a rotation control component, which is connected to at least one induction coil to control the induction coil to rotate around the center of the induction coil.

[0027] Optionally, if the magnetic field emission module includes at least two induction coils, all the induction coils are arranged at a preset angle to the plane of the sputtering platform below or to the side of the sputtering platform.

[0028] The technical advantages of this invention compared to existing technologies are as follows: This invention etches a hole structure with a predetermined aspect ratio onto a substrate to obtain a substrate with a hole structure. A first metal material is used to deposit a metal induction layer on the surface of the substrate and the hole structure, resulting in a substrate with the metal induction layer. A second metal material is then used for magnetron sputtering on the substrate with the metal induction layer, and a magnetic field is applied around the substrate to form a metal film on the surface of the metal induction layer, resulting in a substrate with completed metallization deposition of the hole structure. Using a metal induction method improves the metal coverage within the holes, and combining this with the applied magnetic field ensures uniform particle deposition within the holes, effectively addressing deep hole scenarios. Attached Figure Description

[0029] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 This is a schematic flowchart of a porous metallization deposition method provided in Embodiment 1 of the present invention;

[0031] Figure 2 This is a process comparison diagram of a porous metallization deposition method provided in Embodiment 2 of the present invention;

[0032] Figure 3 This is a schematic diagram of the structure of a magnetron sputtering device provided in Embodiment 3 of the present invention;

[0033] Among them, 1 is the chamber, 2 is the vacuum pump group, 3 is the substrate, 4 is the target material, 31 is the metal induction layer, and 32 is the metal film. Detailed Implementation

[0034] To make the technical problems solved, the technical solutions, and the beneficial effects of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0035] like Figure 1 The diagram shown is a flowchart illustrating a porous metallization deposition method according to Embodiment 1 of the present invention. This porous metallization deposition method may include the following steps:

[0036] Step S101: Etch a hole structure with a preset aspect ratio on the substrate to be processed to obtain a substrate with a hole structure.

[0037] The substrate to be processed can be any type of semiconductor wafer, such as a silicon wafer, and the corresponding hole structure is TSV.

[0038] The preset aspect ratio can be designed according to requirements. For example, if it is a circular hole, the diameter of the circular hole is 10μm and the depth is 150μm, and the aspect ratio is 15:1.

[0039] Optionally, etching a hole structure with a preset aspect ratio on the substrate to be processed to obtain a substrate with the hole structure includes:

[0040] After coating the substrate with adhesive, patterned exposure is performed to obtain the first substrate;

[0041] After etching the first substrate to form a hole structure with a preset aspect ratio, a resist removal cleaning is performed to obtain a substrate with a hole structure.

[0042] The process of using substrate → resist coating → exposure patterning → etching to form deep holes → resist removal and cleaning can improve the efficiency of hole structure fabrication.

[0043] Optionally, etching a hole structure with a preset aspect ratio on the substrate to be processed to obtain a substrate with the hole structure includes:

[0044] After depositing a hard mask on the substrate to be processed, a photoresist coating and patterned exposure are performed to obtain a second substrate;

[0045] The second substrate is etched using a hard mask to form a hole structure with a preset aspect ratio. Then, a photoresist removal cleaning is performed to obtain a substrate with a hole structure.

[0046] The process of using substrate → deposition of hard mask → coating of resist → exposure patterning → etching of hard mask → etching of substrate → deep hole → resist removal and cleaning can improve the accuracy of hole structure fabrication.

[0047] Step S102: Using a first metal material, surface deposition is performed on the substrate with the pore structure, so that the substrate and the surface of the pore structure have a metal induction layer, thereby obtaining a substrate with a metal induction layer.

[0048] In this process, surface deposition is used to create a metal-inducing layer on the sidewalls, bottom surface, and substrate surface of the hole structure. The thickness of the metal-inducing layer can be designed according to requirements. Due to the presence of the metal-inducing layer, the metal bonding ability of subsequent metal sputtering can be guaranteed, and the metal coverage in the hole structure can be improved.

[0049] In one embodiment, a continuous metal induction layer is formed on the inner wall of the deep hole and the surface of the substrate. The metal induction layer is one or more components of Cu, Al, or other conductive materials, with a thickness of 5–100 nm.

[0050] Optionally, the surface deposition on the substrate having a porous structure includes:

[0051] The substrate with the porous structure is surface-deposited using ALD, CVD, or electroplating methods.

[0052] Chemical vapor deposition (CVD) offers advantages such as high uniformity of deposited films, good selective deposition performance, and relatively low deposition temperature, making it suitable for functional film deposition in this invention. However, while CVD deposition of copper films can achieve good film coverage in trenches with high aspect ratios, its application is limited when the aspect ratio exceeds a certain value (e.g., greater than 10:1). The choice of CVD method should be based on the required aspect ratio of the pore structure.

[0053] Atomic Layer Deposition (ALD), also known as Atomic Layer Epitaxial Growth (ALE), is another form of CVD. ALD technology can precisely control the thickness of the deposited film, and the deposited film has good uniformity and conformity. ALD technology can deposit copper films with 100% coverage in trenches / vias with an aspect ratio greater than 35:1.

[0054] Based on the design of the pore structure and the actual requirements for efficiency and cost, one of ALD, CVD, or electroplating can be selected for deposition to achieve the formation of the metal-induced layer.

[0055] Optionally, when performing surface deposition on the porous substrate using ALD, the first metal material is copper, copper oxide is used as a precursor, hydrogen is used as a reducing agent, the reaction temperature is 200℃-300℃, and the deposition is performed in 150-300 cycles.

[0056] Taking the ALD deposition induced layer as an example, a thin conductive metal layer is deposited on the substrate surface and inside deep holes using an ALD device, with the deposition of metallic Cu as an example. The precursors for ALD-deposited Cu films can be classified into copper-halogen, copper-oxygen, copper-nitrogen, oxygen-copper-nitrogen, and copper-carbon precursors. Taking copper-oxygen Cu(acac)2 as the precursor and H2 as the reducing agent, the reaction temperature is about 200℃-300℃ (the deposition temperature is related to the properties of the precursor), the number of cycles is about 150-300 times, and the Cu film thickness is 10±2nm as an example.

[0057] The process is briefly described as follows:

[0058] Cu(acac)2 pulse 0.1s → N2 purge 15s → H2 pulse 0.05s → N2 purge 20s, cycle 250 times.

[0059] Step S103: Using a second metal material, magnetron sputtering is performed on the substrate with the metal induction layer, and a magnetic field is applied around the substrate with the metal induction layer to form a metal film on the surface of the metal induction layer, thereby obtaining a substrate with a pore structure and metallized deposition.

[0060] Among them, the equipment for performing magnetron sputtering can be selected according to needs. For example, High Power Impulse Magnetron Sputtering (HiPIMS) is a magnetron sputtering technology that uses high pulse peak power and low pulse duty cycle to generate high sputtered metal ionization rate. The peak power of HIPIMS can reach the MW level, but due to the short pulse duration, its average power is the same as that of ordinary magnetron sputtering. In this way, the cathode will not increase the target cooling due to overheating. HIPIMS combines the advantages of low temperature deposition, smooth surface, and no particle defects of magnetron sputtering with the high metal ionization rate, strong film adhesion, and dense coating of arc ion plating. Moreover, the ion beam does not contain large particles, and excellent film-substrate adhesion is obtained while controlling the coating microstructure. It has significant advantages in reducing coating internal stress and improving film density and uniformity.

[0061] In one embodiment, HIPIMS sputtering technology includes HIPIMS and various composite sputtering methods such as DC, RF or MF, which can further improve the sputtering rate.

[0062] This invention significantly modifies traditional magnetron sputtering equipment (details are described in the subsequent system embodiments). By applying an external induction coil and adjusting the power supply to control the magnetic field, the applicability of this technology in deep hole deposition applications is expanded.

[0063] The induced magnetic field consists of an alternating power supply, such as an RF power supply (300KHz~30GHz), with a power of 300W-2000W, and an induction coil. When the induction coil is energized, it generates a magnetic field around it, which is proportional to the current intensity in the conductor. Therefore, the direction of sputtered ions can be controlled by using the Lorentz force constraint of the magnetic field on charged ions, so as to achieve the deposition of sputtered ion state particles into the sidewall and inside the hole, increase the thickness of the metal layer on the sidewall, and improve the uniformity of the metal layer.

[0064] Optionally, when magnetron sputtering is performed on the substrate with the metal induction layer, the second metal material is aluminum, and magnetron sputtering is performed with a sputtering pressure of 0.1-1 Pa, a pulse voltage of 100-1000 V, a frequency of 50-200 Hz, and a duty cycle of less than 70%.

[0065] Here, we take sputtered Al film as an example for explanation. We select Al target material with a purity of better than 5N (99.99%), use Ar gas with a purity of better than 5N as the working gas, and set the sputtering pressure to 0.1-1.0 Pa. The pulse voltage of high-power pulsed magnetron sputtering is 100-1000V, the frequency is 50-200Hz, and the duty cycle is <70%, which is used to generate highly ionized Al3+ ions. The ionization rate of the target particles is better than 70%. Under the action of the generated magnetic field, the metal Al film is continuously deposited in the deep hole. The deposition rate can reach 30-50nm / min, which is 2 times higher than that of traditional sputtering and hundreds of times higher than that of ALD deposition rate.

[0066] like Figure 2 The diagram shown is a comparative process diagram of a porous metallization deposition method provided in Embodiment 2 of the present invention. It can be seen that the traditional process (left side diagram) results in uneven metal layer thickness on the pore sidewalls during deep-hole deposition, while the deposition effect obtained using the method of the present invention (right side diagram) shows higher coverage and better metal layer uniformity.

[0067] This invention involves etching a hole structure with a predetermined aspect ratio onto a substrate to obtain a substrate with the hole structure. A first metal material is then deposited on the surface of the substrate with the hole structure, resulting in a metal-inducing layer on the surface of both the substrate and the hole structure. A second metal material is then used for magnetron sputtering on the substrate with the metal-inducing layer, and a magnetic field is applied around the substrate to form a metal film on the surface of the metal-inducing layer, thus obtaining a substrate with completed metallization deposition of the hole structure. Using a metal-inducing method improves the metal coverage within the holes, and combining this with the applied magnetic field ensures uniform particle deposition within the holes, effectively addressing deep hole scenarios.

[0068] like Figure 3 The diagram shown is a structural schematic of a magnetron sputtering device according to Embodiment 3 of the present invention. The present invention provides a hole structure metallization deposition system comprising: an etching device, a deposition device, and a magnetron sputtering device; the etching device is used to etch a hole structure with a preset aspect ratio on a substrate to be processed, obtaining a substrate with a hole structure; the deposition device is used to perform surface deposition on the substrate with the hole structure using a first metal material, so that the surface of the substrate and the hole structure has a metal induction layer, obtaining a substrate with a metal induction layer; a magnetic field emission module is provided at the sputtering platform inside the chamber of the magnetron sputtering device, the sputtering platform being used to support the substrate with the metal induction layer; the magnetron sputtering device is used to perform magnetron sputtering on the substrate with the metal induction layer using a second metal material, and uses the magnetic field emission module to apply a magnetic field around the substrate with the metal induction layer, so that a metal film is formed on the surface of the metal induction layer, obtaining a substrate with completed hole structure metallization deposition.

[0069] exist Figure 3 In this process, the magnetron sputtering equipment includes a chamber 1, a vacuum pump group 2, a substrate 3, and a target 4. The vacuum pump group 2 is used to evacuate the chamber 1. Corresponding pipelines are designed from the upper left position of the chamber 1 to inject an inert gas (such as Ar) into the chamber 1. The substrate 3 shows multiple pore structures, each of which includes a metal induction layer 31 and a metal film 32. The target 4 is installed in a corresponding position to be powered by a high-power pulsed magnetron power supply to bombard the target 4 and form plasma.

[0070] In addition, an induction coil is disposed below the substrate 3 and connected to an RF power supply, thereby forming an induced magnetic field around the substrate 3, and the induction coil can be controlled to rotate, so as to form a variable magnetic field.

[0071] Optionally, the magnetic field emitting module includes at least one induction coil and an alternating power supply, wherein the alternating power supply is connected to all induction coils to generate a magnetic field. The induced magnetic field can be adjusted as needed, making it more adaptable than a fixed magnetic field.

[0072] Optionally, the magnetic field emitting module further includes a rotation control component, which is connected to at least one induction coil to control the induction coil to rotate around the center of the induction coil.

[0073] In this method, an induction coil is applied near the substrate, and a changing magnetic field is generated by the change of current. The induction coil can be a single rotating coil with a rotation speed of 0 rpm to 20 rpm, forming a variable magnetic field. This eliminates the need to design multiple induction coils and reduces costs.

[0074] Optionally, if the magnetic field emission module includes at least two induction coils, all the induction coils are arranged at a preset angle to the plane of the sputtering platform below or to the side of the sputtering platform.

[0075] Among them, there can be multiple induction coils, and their positions can be fixed at a certain angle below or to the side of the wafer to control the ion movement trajectory, which can meet the sputtering deposition of all hole structures in the substrate.

[0076] The closest solution to this invention is the direct deposition of metal thin films using ALD technology. However, this technology has low production efficiency (approximately 5 nm / h), and it takes tens of hours to deposit 200 nm-level metal thin films on the sidewalls of deep holes such as TSVs. This invention leverages the advantages of sputtering for fast film growth (better than 30 nm / min) and solves the problem of poor conformability of sputtering deposition technology in deep hole deposition. It expands the application scenarios and not only makes the coverage inside the hole comparable to the ALD deposition process, but also increases the production efficiency by more than 100 times.

[0077] The above-described embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included within the protection scope of the present invention.

Claims

1. A method for depositing porous metallization, characterized in that, include: A hole structure with a preset aspect ratio is etched on the substrate to be processed to obtain a substrate with a hole structure. A first metal material is used to deposit a metal induction layer on the surface of the substrate with the pore structure, so that the substrate and the surface of the pore structure have a metal induction layer, thereby obtaining a substrate with a metal induction layer. A second metal material is used to perform magnetron sputtering on the substrate with the metal induction layer, and a magnetic field is applied around the substrate with the metal induction layer to form a metal film on the surface of the metal induction layer, thereby obtaining a substrate with a pore structure and metallized deposition.

2. The porous metallization deposition method according to claim 1, characterized in that, The process of etching a hole structure with a predetermined aspect ratio on the substrate to be processed, to obtain a substrate with the hole structure, includes: After coating the substrate with adhesive, patterned exposure is performed to obtain the first substrate; After etching the first substrate to form a hole structure with a preset aspect ratio, a resist removal cleaning is performed to obtain a substrate with a hole structure.

3. The porous metallization deposition method according to claim 1, characterized in that, The process of etching a hole structure with a predetermined aspect ratio on the substrate to be processed to obtain a substrate with the hole structure includes: After depositing a hard mask on the substrate to be processed, a photoresist coating and patterned exposure are performed to obtain a second substrate; The second substrate is etched using a hard mask to form a hole structure with a preset aspect ratio. Then, a photoresist removal cleaning is performed to obtain a substrate with a hole structure.

4. The porous metallization deposition method according to claim 1, characterized in that, The surface deposition on the substrate with the porous structure includes: The substrate with the porous structure is surface-deposited using ALD, CVD, or electroplating methods.

5. The porous metallization deposition method according to claim 4, characterized in that, When performing surface deposition on the porous substrate using ALD, the first metal material is copper, copper oxide is used as a precursor, hydrogen is used as a reducing agent, the reaction temperature is 200℃-300℃, and the deposition is performed in 150-300 cycles.

6. The porous metallization deposition method according to claim 1, characterized in that, When magnetron sputtering is performed on the substrate with the metal induction layer, the second metal material is aluminum, and magnetron sputtering is performed with a sputtering pressure of 0.1-1 Pa, a pulse voltage of 100-1000 V, a frequency of 50-200 Hz, and a duty cycle of less than 70%.

7. A porous metallization deposition system, characterized in that, The pore structure metallization deposition system includes: etching equipment, deposition equipment, and magnetron sputtering equipment; The etching equipment is used to etch a hole structure with a preset aspect ratio on the substrate to be processed, so as to obtain a substrate with a hole structure. The deposition equipment is used to perform surface deposition of a first metal material on the substrate with a porous structure, so that the substrate and the surface of the porous structure have a metal induction layer, thereby obtaining a substrate with a metal induction layer. A magnetic field emission module is provided at the sputtering platform inside the chamber of the magnetron sputtering equipment, and the sputtering platform is used to support the substrate with the metal induction layer; The magnetron sputtering equipment is used to perform magnetron sputtering on the substrate with the metal induction layer using a second metal material, and to apply a magnetic field around the substrate with the metal induction layer using the magnetic field emission module, so that a metal film is formed on the surface of the metal induction layer, resulting in a substrate with a pore structure and metallized deposition.

8. The porous metallization deposition system according to claim 7, characterized in that, The magnetic field emitting module includes at least one induction coil and an alternating power supply, the alternating power supply being connected to all induction coils so that the induction coils generate a magnetic field.

9. The porous metallization deposition system according to claim 8, characterized in that, The magnetic field emitting module also includes a rotation control component, which is connected to at least one induction coil to control the induction coil to rotate around the center of the induction coil.

10. The porous metallization deposition system according to claim 8, characterized in that, If the magnetic field emission module includes at least two induction coils, then all the induction coils are arranged at a preset angle to the plane of the sputtering platform, either below or to the side of the sputtering platform.

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