A method for preparing micro / nano three-dimensional hybrid structures

Abstract

This invention discloses a method for fabricating a micro / nano three-dimensional hybrid structure, comprising: sequentially forming a metal film layer and a photoresist layer on a substrate; etching the photoresist layer according to a preset pattern to form a patterned photoresist layer; removing exposed areas of the metal film layer while retaining residual metal particles injected into the substrate in the exposed areas, wherein the exposed areas are regions of the metal film layer not covered by the patterned photoresist layer; removing the patterned photoresist layer; and treating the substrate using a metal-assisted chemical etching process, thereby forming the micro / nano three-dimensional hybrid structure through the catalysis of the metal film layer and the residual metal particles. This provides a method for forming specific structures in substrate regions without pattern designs while simultaneously etching the substrate using a patterned design.

Description

Technical Field

[0001] This invention relates to the field of semiconductor technology, and in particular to a method for fabricating micro / nano three-dimensional hybrid structures. Background Technology

[0002] With the development of modern science and technology, the preparation and application of nanomaterials has attracted widespread attention. Among numerous novel microstructures, silicon-based nano / microstructures have garnered significant interest due to their superior properties and excellent process compatibility, showing great promise for applications in advanced electronic devices, optoelectronic devices, and photovoltaic devices.

[0003] Currently, the fabrication methods for this type of microstructure can be broadly classified into two categories: dry etching and wet etching. Dry etching involves bombarding the exposed portions of the target material with plasma, removing some material from the exposed surface to form a specific patterned structure. However, using high-energy ions to bombard the semiconductor surface carries the risk of damaging the semiconductor's electrical and optical properties. Wet etching methods include wet anisotropic etching, photo-assisted electrochemical etching (PEC), metal-assisted chemical etching (MACE), etc., and these methods cause less damage compared to dry etching.

[0004] However, existing wet etching methods often perform patterned etching according to the pattern of the layout, which cannot meet the needs of other etching structures in areas without pattern design, and the application is relatively limited. Summary of the Invention

[0005] In view of the above problems, the present invention is proposed to provide a method for preparing micro / nano three-dimensional hybrid structures that overcomes or at least partially solves the above problems.

[0006] A method for fabricating micro / nano three-dimensional hybrid structures is provided, comprising:

[0007] A metal film layer and a photoresist layer are sequentially formed on the substrate;

[0008] According to the preset layout pattern, the photoresist layer is etched to form a patterned photoresist layer;

[0009] Remove the exposed area of ​​the metal film layer, while retaining the residual metal particles injected into the substrate in the exposed area. The exposed area is the metal film layer area not covered by the patterned photoresist layer.

[0010] Remove the patterned photoresist layer;

[0011] The substrate is treated with a metal-assisted chemical etching process, and the micro-nano three-dimensional hybrid structure is formed by the catalysis of the metal film and the residual metal particles.

[0012] Optionally, the substrate is a silicon substrate, and the metal film layer is made of Au, Ag, or Cu.

[0013] Optionally, the thickness of the metal film layer is 10–30 nm.

[0014] Optionally, before sequentially forming the metal film layer and the photoresist layer on the substrate, the method further includes: sequentially performing ultrasonic cleaning of the substrate with acetone, ultrasonic cleaning with ethanol, and cleaning with deionized water; and drying the substrate with nitrogen gas.

[0015] Optionally, the step of forming the metal film layer on the substrate includes: forming the metal film layer on the substrate using electron beam evaporation or magnetron sputtering.

[0016] Optionally, removing the exposed area of ​​the metal film layer includes: using ion beam etching technology to etch and remove the exposed area of ​​the metal film layer.

[0017] Optionally, the metal-assisted chemical etching process for treating the substrate includes: etching the substrate with an etching solution, wherein the etching solution includes hydrofluoric acid, hydrogen peroxide, and deionized water.

[0018] Optionally, the volume ratio of the hydrofluoric acid to the hydrogen peroxide is 5:1 to 10:1.

[0019] Optionally, the etching time for etching the substrate with the etching solution is 10 to 20 hours.

[0020] Optionally, after forming the micro-nano three-dimensional hybrid structure, the method further includes: sequentially cleaning the micro-nano three-dimensional hybrid structure with iodine solution, isopropanol, and drying it.

[0021] The technical solutions provided in the embodiments of the present invention have at least the following technical effects or advantages:

[0022] The method for fabricating micro / nano three-dimensional hybrid structures provided in this invention involves sequentially depositing a metal film and a photoresist layer on a substrate, then patterning the photoresist layer, and removing the exposed areas of the metal film to retain residual metal particles in the substrate. When the substrate treated in this way is then subjected to metal-assisted chemical etching, the metal film area, due to its high metal content, will catalyze the etching to form deeper trench structures, meeting the requirements of patterned etching. In the substrate areas without patterned designs, the residual metal particles catalyze the etching of the substrate, forming nanoporous structures. This provides a method for forming specific structures in substrate areas without patterned designs while simultaneously etching the substrate through patterned etching. This type of micro / nano three-dimensional hybrid structure can be applied to optical devices.

[0023] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, and in order to make the above and other objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention are described below. Attached Figure Description

[0024] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0025] Figure 1 This is a flowchart illustrating the preparation method of the micro / nano three-dimensional hybrid structure in an embodiment of the present invention;

[0026] Figure 2 The fabrication process of the micro / nano three-dimensional hybrid structure in the embodiments of the present invention. Figure 1 ;

[0027] Figure 3 The fabrication process of the micro / nano three-dimensional hybrid structure in the embodiments of the present invention. Figure 2 ;

[0028] Figure 4 The fabrication process of the micro / nano three-dimensional hybrid structure in the embodiments of the present invention. Figure 3 ;

[0029] Figure 5 The fabrication process of the micro / nano three-dimensional hybrid structure in the embodiments of the present invention. Figure 4 ;

[0030] Figure 6 The fabrication process of the micro / nano three-dimensional hybrid structure in the embodiments of the present invention. Figure 5 . Detailed Implementation

[0031] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings.

[0032] The accompanying drawings illustrate various structural schematics according to embodiments of the present disclosure. These drawings are not to scale, and some details have been enlarged for clarity, and some details may have been omitted. The shapes of the various regions and layers shown in the drawings, as well as their relative sizes and positional relationships, are merely exemplary and may deviate from reality due to manufacturing tolerances or technical limitations. Furthermore, those skilled in the art can design regions / layers with different shapes, sizes, and relative positions as needed.

[0033] In the context of this disclosure, when a layer / component is referred to as being "above" another layer / component, that layer / component may be directly above the other layer / component, or there may be an intermediate layer / component between them. Additionally, if a layer / component is "above" another layer / component in one orientation, then when the orientation is reversed, that layer / component may be "below" the other layer / component. In the context of this disclosure, similar or identical components may be denoted by the same or similar reference numerals.

[0034] To better understand the above technical solutions, the following will describe the above technical solutions in detail with reference to specific implementation methods. It should be understood that the embodiments of this disclosure and the specific features in the embodiments are detailed descriptions of the technical solutions of this application, rather than limitations on the technical solutions of this application. In the absence of conflict, the embodiments of this application and the technical features in the embodiments can be combined with each other.

[0035] This invention provides a method for preparing micro / nano three-dimensional hybrid structures, comprising:

[0036] Step S101: A metal film layer and a photoresist layer are sequentially formed on the substrate;

[0037] Step S102: Etch the photoresist layer according to the preset layout pattern to form a patterned photoresist layer;

[0038] Step S103: Remove the exposed area of ​​the metal film layer, and retain the residual metal particles injected into the substrate in the exposed area. The exposed area is the metal film layer area not covered by the patterned photoresist layer.

[0039] Step S104: Remove the patterned photoresist layer;

[0040] Step S105: The substrate is treated with a metal-assisted chemical etching process, and the micro-nano three-dimensional hybrid structure is formed by the catalysis of the metal film and the residual metal particles.

[0041] The following is combined with Figure 2-6 The implementation process steps of this embodiment are described in detail below:

[0042] First, a substrate 1 is provided, which can be a silicon substrate, a germanium substrate, or other semiconductor substrate. Before performing step S101, the substrate 1 can be cleaned to remove contaminants and organic matter from its surface. Specifically, the substrate 1 can be sequentially subjected to ultrasonic cleaning with acetone, ultrasonic cleaning with ethanol, and cleaning with deionized water, and then the substrate can be dried with nitrogen gas.

[0043] like Figure 2In step S101, a metal film layer 2 and a photoresist layer 3 are sequentially formed on the provided substrate 1. Specifically, the metal film layer 2 can be made of noble metals such as Au, Ag, or Cu. The thickness of the metal film layer 2 is 10–30 nm, preferably 20 nm, to meet the requirements of the subsequent metal-assisted chemical etching process.

[0044] In one alternative embodiment, the process of forming the metal film layer 2 on the substrate 1 can employ electron beam evaporation or magnetron sputtering. Alternatively, processes such as vapor deposition or spraying can be used, and no limitation is made herein.

[0045] A photoresist layer 3 is formed on the metal film layer 2. This photoresist layer 3 can be a negative photoresist, such as NR1500, or a positive photoresist; there are no restrictions, as long as the corresponding pattern and etching solution are set according to the photoresist type. Specifically, the photoresist layer 3 can be formed on the metal film layer 2 using a spin coating process. For example, a spin coater can be used to spin-coat the photoresist over the deposited metal film layer 2 at a speed of 3500 to 4500 revolutions per minute to form the photoresist layer 3.

[0046] like Figure 3 As shown, in step S102, the photoresist layer 3 is etched according to a preset pattern to form a patterned photoresist layer 3. Specifically, the photoresist layer 3 can be exposed using a pre-made pattern through photolithography, and then developed to form the desired shape pattern on the photoresist layer 3. The pattern setting and the developer setting are matched to the photoresist type.

[0047] After the photoresist layer 3 is patterned, the area where the photoresist has been removed will reveal the surface of the metal film layer 2, i.e., the exposed area of ​​the metal film layer.

[0048] Next, as Figure 4 As shown, step S103 is performed to remove the exposed area of ​​the metal film layer 2, while retaining the residual metal particles 4 injected into the substrate in the exposed area. The exposed area is the metal film layer area not covered by the patterned photoresist layer. Specifically, when the metal film layer 2 is formed on the substrate 1, some of the metal particles 4 in the metal film layer 2 are injected into the substrate. After removing the metal film layer 2 in this area, these metal particles 4 will remain in the substrate 1.

[0049] In one alternative embodiment, the exposed areas of the metal film 2 can be removed using an ion beam etching process to etch away the metal film 2 not covered by the photoresist layer 3. Of course, a wet etching process can also be used, and there is no limitation on this.

[0050] Then, as Figure 5As shown, step S104 is executed to remove the patterned photoresist layer 3. Specifically, a stripping process can be used to remove the patterned photoresist layer 3, that is, to remove the photoresist layer 3 covering the unetched metal film layer 2. After removing the photoresist layer 3, only the portion of the metal film layer 2 previously covered by the photoresist layer 3 and the metal particles remaining on the substrate 1 after removing the exposed area of ​​the metal film layer 2 are left on the substrate 1.

[0051] Next, as Figure 6 As shown, in step S105, the substrate 1 is treated with a metal-assisted chemical etching process. Through the catalysis of the metal film layer 2 and the residual metal particles, a... Figure 6 The micro / nano three-dimensional hybrid structure shown.

[0052] In one optional embodiment, the metal-assisted chemical etching process for substrate 1 can involve etching substrate 1 with an etching solution comprising hydrofluoric acid, hydrogen peroxide, and deionized water. Further, the volume ratio of hydrofluoric acid to hydrogen peroxide in the etching solution can be set to 5:1 to 10:1 to achieve better etching effect and efficiency. The etching time for substrate 1 can be 10 to 20 hours. For example, a solution can be prepared using 49.5% hydrofluoric acid, 30% hydrogen peroxide, and deionized water by mass percentage, with a volume ratio of 7:1:20 to form the etching solution. An etching time of 15 hours can form a micro / nano three-dimensional hybrid structure, which can be a nano / micron three-dimensional hybrid structure. The mass fractions of the hydrofluoric acid and hydrogen peroxide solutions are not limited; any existing mass fraction solutions are acceptable.

[0053] Specifically, during the metal-assisted chemical etching process, the areas where the remaining metal film 2 has a large metal content will catalyze the etching to form deeper channel structures, creating channel patterns 601 that meet the patterning requirements of the design. In the substrate areas without pattern design, i.e., where the metal film 2 has been removed, residual metal particles catalyze the etching of the substrate, forming nanoporous structures 602. Thus, while etching the substrate through patterning, specific structures can also be formed in the substrate areas without pattern design. This type of micro / nano three-dimensional hybrid structure can be used as a basic structure for the fabrication of optical devices.

[0054] In an optional implementation, after forming the micro / nano three-dimensional hybrid structure, the structure can be sequentially cleaned with iodine solution, isopropanol, and dried to reduce residual impurities. For example, the sample can be placed in a mixed aqueous solution of 10% potassium iodide and 2.5% iodine to remove the Au film, followed by cleaning with isopropanol and air drying. The mass fractions of the potassium iodide and iodine solutions are not limited; any existing solutions with the specified mass fraction ratios are acceptable.

[0055] The technical solutions provided in the embodiments of the present invention have at least the following technical effects or advantages:

[0056] The method for fabricating micro / nano three-dimensional hybrid structures provided in this invention involves sequentially depositing a metal film and a photoresist layer on a substrate, then patterning the photoresist layer, and removing the exposed areas of the metal film to retain residual metal particles in the substrate. When the substrate treated in this way is then subjected to metal-assisted chemical etching, the metal film area, due to its high metal content, will catalyze the etching to form deeper trench structures, meeting the requirements of patterned etching. In the substrate areas without patterned designs, the residual metal particles catalyze the etching of the substrate, forming nanoporous structures. This provides a method for forming specific structures in substrate areas without patterned designs while simultaneously etching the substrate through patterned etching. This type of micro / nano three-dimensional hybrid structure can be applied to optical devices.

[0057] Numerous specific details are set forth in the specification provided herein. However, it will be understood that embodiments of the invention may be practiced without these specific details. In some instances, well-known methods, structures, and techniques have not been shown in detail so as not to obscure the understanding of this specification.

[0058] Similarly, it should be understood that, in order to simplify this disclosure and aid in understanding one or more of the various aspects of the invention, in the above description of exemplary embodiments of the invention, various features of the invention are sometimes grouped together in a single embodiment, figure, or description thereof. However, this method of disclosure should not be construed as reflecting an intention that the claimed invention requires more features than are expressly recited in each claim. Rather, as reflected in the following claims, inventive aspects lie in fewer than all features of a single foregoing disclosed embodiment. Therefore, the claims following the detailed description are hereby expressly incorporated into this detailed description, wherein each claim itself is a separate embodiment of the invention.

[0059] It should be noted that the above embodiments are illustrative of the invention and not restrictive, and that those skilled in the art can devise alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses should not be construed as limiting the claims. The word "comprising" does not exclude the presence of components or steps not listed in the claims. The word "a" or "an" preceding a component does not exclude the presence of a plurality of such components. The invention can be implemented by means of hardware comprising several different components and by means of a suitably programmed computer. In the unit claims enumerating several means, several of these means may be embodied by the same item of hardware. The use of the words first, second, and third, etc., does not indicate any order. These words can be interpreted as names.

Claims

1. A method for preparing a micro-nano three-dimensional hybrid structure, characterized in that, The application relates to a method for forming a micro-nano three-dimensional mixed structure on a substrate. A metal film layer and a photoresist layer are sequentially formed on the substrate; According to a preset layout pattern, the photoresist layer is etched to form a patterned photoresist layer; The exposed area of the metal film layer is removed, and residual metal particles in the exposed area of the substrate are reserved; The patterned photoresist layer is removed; The substrate is treated by a metal-assisted chemical etching process, and the micro-nano three-dimensional mixed structure is formed through catalysis of the metal film layer and the residual metal particles.

2. The method of claim 1, wherein, The substrate is a silicon substrate, and the material of the metal film layer is Au, Ag or Cu.

3. The method of claim 1, wherein, The thickness of the metal film layer is 10-30 nm.

4. The method of claim 1, wherein, Before the step of sequentially forming the metal film layer and the photoresist layer on the substrate, the method further comprises the following steps: The substrate is sequentially subjected to acetone ultrasonic cleaning, ethanol ultrasonic cleaning and deionized water cleaning; The substrate is dried by nitrogen.

5. The method of claim 1, wherein, The step of forming the metal film layer on the substrate comprises the following steps: The metal film layer is formed on the substrate by adopting an electron beam evaporation technology or a magnetron sputtering technology.

6. The method of claim 1, wherein, The step of removing the exposed area of the metal film layer comprises the following steps: The exposed area of the metal film layer is etched and removed by adopting an ion beam etching technology.

7. The method of claim 1, wherein, The step of treating the substrate by the metal-assisted chemical etching process comprises the following steps: The substrate is etched by adopting an etching solution, and the etching solution comprises hydrofluoric acid, hydrogen peroxide and deionized water.

8. The method of claim 7, wherein, The volume ratio of the hydrofluoric acid to the hydrogen peroxide is 5:1-10:

1.

9. The method of claim 7, wherein, The etching time of the substrate by the etching solution is 10-20 hours.

10. The method of claim 1, wherein, After the step of forming the micro-nano three-dimensional mixed structure, the method further comprises the following steps: The micro-nano three-dimensional mixed structure is sequentially subjected to iodine solution cleaning, isopropyl alcohol cleaning and drying.

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