Method for manufacturing infrared detector tiled substrate

Abstract

This invention discloses a method for fabricating an infrared detector splicing substrate. The method includes: cleaning the substrate; fabricating at least one positioning mark on the first surface of the cleaned substrate, the positioning mark being a metal pattern with a thickness of h; and fabricating at least one metal lead on the first surface after the positioning mark is fabricated, the metal lead having a thickness of H, and satisfying that H > h. By using this invention, by separately fabricating the positioning mark pattern and the metal lead pattern on the splicing substrate and designing different film thicknesses, the current carrying capacity of the electrical lead structure is satisfied while improving the pattern processing accuracy of the splicing alignment mark, reducing the processing difficulty of the splicing substrate, and thus improving the splicing accuracy of the detector submodules.

Description

Technical Field

[0001] This invention relates to the field of infrared detector technology, and in particular to a method for preparing an infrared detector splicing substrate. Background Technology

[0002] Infrared detector components have wide applications in various fields and are core components of infrared photoelectric detection systems for acquiring target information. To improve signal acquisition capabilities, the pixel pitch of infrared detectors has been continuously decreasing, the array size has been continuously increasing, and multiple spectral bands may be integrated depending on requirements. However, limitations imposed by factors such as the size of infrared detector materials, the maturity of detector chip fabrication processes, and cost make it difficult to increase the array size of a single chip without restriction. Furthermore, limitations imposed by the optical and electrical properties of detector materials make it difficult to achieve coverage detection of three or more optical spectral bands on a single chip. Integrating multiple small-scale detector sub-modules with different response spectral bands through splicing is an economical and feasible technical solution with high flexibility.

[0003] To achieve effective coverage of the imaging field of view, the relative positional error between modules must be within the micrometer level, which places very high demands on the design of each step of the splicing process.

[0004] During the splicing process, the splicing position of the sub-modules needs to be determined by positioning marks prepared on both the detector sub-modules and the splicing substrate. Therefore, in addition to being limited by the capabilities of the splicing equipment itself, the graphic processing accuracy of the positioning marks also contributes significantly to the splicing accuracy.

[0005] Besides serving as a common carrier for multiple sub-modules, supporting and fixing them, the splicing substrate also acts as a transitional carrier for electrical connections between the detector sub-modules and peripheral systems via wire bonding. Therefore, the patterns on the splicing substrate typically include positioning marker patterns and metal lead patterns. Positioning marker patterns are only used for positioning the detector sub-modules. The main requirements for positioning marker patterns are clear, complete, and distortion-free edges, a clean and bright surface, and consistent pattern dimensions with the design values. There are no specific requirements for the thickness of the metal film layer. Metal lead patterns require a thicker, low-resistivity metal film layer to ensure reliable contact between the lead and the metal film layer during wire bonding between the substrate and the chip, and between the substrate and peripheral systems. A clean and bright surface is required, and the requirements for the edge morphology are lower than for positioning marker patterns. To ensure the lead's ability to carry current signals, the lead pattern dimensions are designed with redundancy. A reduction in pattern size within 10% of the design size after processing does not affect electrical performance; therefore, a certain deviation between the final pattern size and the design value is permissible.

[0006] Currently, both types of graphic structures are manufactured using the same process and completed simultaneously. The processing flow is detailed below. Figure 1Because the electrical lead structure requires a thick metal film, a thick photoresist mask is needed regardless of whether etching or lift-off is used. It's difficult to achieve perfectly vertical sidewalls on a thick photoresist mask. The thicker the mask, the more difficult it is to maintain verticality, leading to a greater dimensional difference between the upper and lower surfaces of the photoresist mask pattern. This results in a larger deviation between the pattern size at the contact surface between the photoresist mask and the underlying substrate and the design value. If a dry etching process is used, the overall size of the photoresist mask gradually shrinks with increasing etching time, causing the size of the metal pattern beneath it to shrink accordingly. If a wet lift-off process is used, the size of the metal pattern on the substrate depends on the pattern size at the contact surface between the photoresist mask and the substrate. Again, because the sidewalls of the photoresist mask are difficult to keep vertical, the final metal pattern size exhibits significant deformation. Therefore, transferring the pattern with high precision to the splicing substrate is very difficult, affecting the final sub-module splicing positioning accuracy. Summary of the Invention

[0007] This invention provides a method for preparing an infrared detector splicing substrate, which solves the problem of poor splicing substrate manufacturing accuracy caused by the simultaneous fabrication of positioning mark patterns and metal lead patterns using the same process in the prior art.

[0008] The method for preparing an infrared detector splicing substrate according to an embodiment of the present invention includes:

[0009] Clean the substrate;

[0010] At least one positioning mark is prepared on the first surface of the cleaned substrate, the positioning mark being a metal pattern with a thickness of h;

[0011] At least one metal lead is prepared on the first surface after the positioning mark is prepared. The thickness of the metal lead is H, and H > h.

[0012] According to some embodiments of the present invention, the step of preparing at least one positioning mark on the first surface of the cleaned substrate includes:

[0013] A first metal layer of thickness h is deposited on the first surface of the cleaned substrate.

[0014] A first photoresist mask pattern is prepared on the surface of the first metal layer;

[0015] An etching process is used to remove the portion of the first metal layer that is not covered by the first photoresist mask pattern.

[0016] According to some embodiments of the present invention, a first photoresist mask pattern is prepared on the surface of the first metal layer, including:

[0017] A low-viscosity positive photoresist with a thickness of 1 μm to 2 μm is coated on the surface of the first metal layer;

[0018] The substrate coated with the first positive photoresist was placed in an environment of 90℃~130℃ and baked for 5min~20min;

[0019] The baked substrate is placed in a photolithography machine for exposure and developed with a developer to form the first photoresist mask pattern;

[0020] The substrate with the first photoresist mask pattern is placed in an environment of 90℃~130℃ and baked for 5min~20min.

[0021] According to some embodiments of the present invention, the etching process for removing the portion of the first metal layer not covered by the first photoresist mask pattern includes:

[0022] The substrate with the first photoresist mask pattern prepared is placed in an ion milling machine with the first surface facing the ion source. Physical etching is performed using an ion current with a beam voltage of 250V to 500V and a beam current of 30mA to 120mA to remove the portion of the first metal layer not covered by the first photoresist mask pattern.

[0023] According to some embodiments of the present invention, the step of preparing at least one positioning mark on the first surface of the cleaned substrate further includes:

[0024] The first photoresist mask pattern is removed using a wet process.

[0025] According to some embodiments of the present invention, h satisfies:

[0026] According to some embodiments of the present invention, the metal pattern is a Cr metal pattern.

[0027] According to some embodiments of the present invention, the step of preparing at least one metal lead on the first surface after the positioning mark is prepared includes:

[0028] A second photoresist mask pattern is prepared on the first surface after the positioning marks are prepared;

[0029] A second metal layer of thickness H is deposited on the first surface on which the second photoresist mask pattern is prepared;

[0030] The substrate with the second metal layer deposited is immersed in acetone to dissolve the second photoresist mask pattern.

[0031] According to some embodiments of the present invention, the step of preparing a second photoresist mask pattern on the first surface after preparing the positioning marks includes:

[0032] A second, highly viscous photoresist with a thickness of 4 μm to 10 μm is coated on the first surface after the positioning mark is prepared;

[0033] The substrate coated with the second positive photoresist was placed in an environment of 90℃~130℃ and baked for 5min~20min;

[0034] The baked substrate is placed in a photolithography machine for exposure and developed with a developer to form a second photoresist mask pattern.

[0035] The substrate with the second photoresist mask pattern is placed in an environment of 90℃~130℃ and baked for 5min~20min.

[0036] According to some embodiments of the present invention, depositing a second metal layer of thickness H on the first surface on which the second photoresist mask pattern is formed includes:

[0037] A Cr metal layer with a thickness of H1 and an Au metal layer with a thickness of H2 are sequentially deposited on the first surface on which the second photoresist mask pattern is prepared.

[0038] H1 satisfies:

[0039] H2 satisfies:

[0040] By employing the embodiments of the present invention, positioning mark patterns and metal lead patterns on the splicing substrate are prepared separately, and different film thicknesses are designed. While meeting the current carrying capacity of the electrical lead structure, the pattern processing accuracy of the splicing alignment mark is improved, the processing difficulty of the splicing substrate is reduced, and the splicing accuracy of the detector submodule is improved.

[0041] 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

[0042] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of the embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. In the drawings:

[0043] Figure 1 This is a flowchart of the existing method for fabricating an infrared detector splicing substrate;

[0044] Figure 2 This is a flowchart of the method for preparing the infrared detector splicing substrate in an embodiment of the present invention;

[0045] Figure 3 This is a flowchart of the method for preparing the infrared detector splicing substrate in an embodiment of the present invention;

[0046] Figure 4 This is a schematic diagram of the preparation of positioning markers in an embodiment of the present invention;

[0047] Figure 5 This is a schematic diagram of the metal lead fabrication in an embodiment of the present invention;

[0048] Figure 6 This is a schematic diagram of an infrared detector splicing substrate prepared using the infrared detector splicing substrate preparation method described in this embodiment of the invention. Detailed Implementation

[0049] Exemplary embodiments of the invention will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the invention are shown in the drawings, it should be understood that the invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of the invention and to fully convey the scope of the invention to those skilled in the art. Furthermore, 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.

[0050] See Figure 2 The method for preparing an infrared detector splicing substrate according to an embodiment of the present invention includes:

[0051] S1, Cleaning the substrate; This step is used to remove impurities from the substrate, including inorganic particle contamination, organic contamination, etc.

[0052] S2, at least one positioning mark is prepared on the first surface of the cleaned substrate, the positioning mark being a metal pattern with a thickness of h;

[0053] The number, position, and size of the positioning marks are prepared according to a pre-designed plan. The thickness of the positioning mark can be understood as the height by which the positioning mark protrudes from the first surface.

[0054] S3, at least one metal lead is prepared on the first surface after the positioning mark is prepared, the thickness of the metal lead is H, and satisfies: H > h.

[0055] The number, position, and size of the metal leads are also prepared according to a pre-designed plan. The thickness of the metal leads can be understood as the height by which the metal leads protrude from the first surface.

[0056] By employing the embodiments of the present invention, positioning mark patterns and metal lead patterns on the splicing substrate are prepared separately, and different film thicknesses are designed. While meeting the current carrying capacity of the electrical lead structure, the pattern processing accuracy of the splicing alignment mark is improved, the processing difficulty of the splicing substrate is reduced, and the splicing accuracy of the detector submodule is improved.

[0057] Based on the above embodiments, further variant embodiments are proposed. It should be noted that, in order to keep the description brief, only the differences from the above embodiments are described in each variant embodiment.

[0058] According to some embodiments of the present invention, the cleaning substrate includes:

[0059] The substrate was immersed in deionized water and the inorganic particulate contaminants on the surface of the substrate were removed by ultrasonic cleaning.

[0060] The substrate, after being cleaned of inorganic particles, was cleaned in sequence with acetone and ethanol to remove organic contaminants from the surface of the substrate.

[0061] The substrate surface, after being contaminated with organic matter, was purged with dry nitrogen gas to remove residual ethanol reagent.

[0062] Figure 4 This is a schematic diagram illustrating the preparation of positioning markers in an embodiment of the present invention. Figure 4 In the diagram, number 1 represents the substrate, number 2 represents the first metal layer, and number 5 represents the first photoresist mask pattern.

[0063] Reference Figure 4 As shown, according to some embodiments of the present invention, the step of preparing at least one positioning mark on the first surface of the cleaned substrate includes:

[0064] A first metal layer with a thickness of h is deposited on the first surface of the cleaned substrate using physical vapor deposition.

[0065] A first photoresist mask pattern is prepared on the surface of the first metal layer; the formation of the first photoresist mask pattern causes part of the first metal layer to be masked, while other parts are exposed.

[0066] An etching process is used to remove the portion of the first metal layer that is not covered by the first photoresist mask pattern.

[0067] It is understood that the etching process can etch away the portion of the first metal layer that is not covered by the first photoresist mask pattern, while retaining the portion covered by the first photoresist mask pattern, thereby forming at least one positioning mark on the first surface.

[0068] According to some embodiments of the present invention, a first photoresist mask pattern is prepared on the surface of the first metal layer, including:

[0069] A low-viscosity positive photoresist with a thickness of 1 μm to 2 μm is coated on the surface of the first metal layer;

[0070] The substrate coated with the first positive photoresist was placed in an environment of 90℃~130℃ and baked for 5min~20min;

[0071] The baked substrate is placed in a photolithography machine for exposure and developed with a developer to form the first photoresist mask pattern;

[0072] The substrate with the first photoresist mask pattern is placed in an environment of 90℃~130℃ and baked for 5min~20min.

[0073] The first baking process is to evaporate most of the solvent in the photoresist, changing it from a liquid to a solid state, before exposure and development can proceed. The second baking process is to further harden the photoresist mask and improve the adhesion between the photoresist mask and the underlying substrate.

[0074] According to some embodiments of the present invention, the etching process for removing the portion of the first metal layer not covered by the first photoresist mask pattern includes:

[0075] The substrate with the first photoresist mask pattern prepared is placed in an ion milling machine with the first surface facing the ion source. Etching is performed using an ion current with a beam voltage of 250V to 500V and a beam current of 30mA to 120mA to remove the portion of the first metal layer not covered by the first photoresist mask pattern.

[0076] Reference Figure 4 As shown, according to some embodiments of the present invention, the step of preparing at least one positioning mark on the first surface of the cleaned substrate further includes:

[0077] The first photoresist mask pattern is removed using a wet process.

[0078] For example, the etched substrate is immersed in acetone until the first photoresist mask pattern dissolves. Then, the substrate is cleaned with fresh acetone and ethanol in sequence, and the substrate surface is purged with high-purity dry nitrogen to remove the residual ethanol reagent.

[0079] According to some embodiments of the present invention, h satisfies:

[0080] According to some embodiments of the present invention, the metal pattern is a Cr metal pattern.

[0081] According to some embodiments of the present invention, H satisfies:

[0082] Figure 5 This is a schematic diagram of the metal lead fabrication in an embodiment of the present invention. Figure 5 In the diagram, number 1 represents the substrate, number 3 represents the second metal layer, and number 4 represents the second photoresist mask pattern.

[0083] Reference Figure 5 As shown, according to some embodiments of the present invention, the step of preparing at least one metal lead on the first surface after the positioning mark is prepared includes:

[0084] A second photoresist mask pattern is prepared on the first surface after the positioning marks are prepared. In actual operation, the prepared positioning marks can be used to position the second photoresist mask pattern to ensure that the relative positional relationship between the positioning marks and the metal leads meets the design requirements.

[0085] A second metal layer of thickness H is deposited on the first surface side where the second photoresist mask pattern is prepared; in this step, a portion of the second metal layer is directly deposited on the first surface of the substrate, and the remaining portion is deposited on the second photoresist mask pattern.

[0086] The substrate with the second metal layer deposited is immersed in acetone to dissolve the second photoresist mask pattern.

[0087] As a result, acetone reacts with the second photoresist mask pattern and is dissolved. The metal layer deposited on the second photoresist mask pattern also detaches from the substrate, while the metal layer deposited on the first surface of the substrate remains attached to the substrate. This part of the area forms at least one metal lead.

[0088] According to some embodiments of the present invention, the step of preparing a second photoresist mask pattern on the first surface after preparing the positioning marks includes:

[0089] A 4μm to 10μm thick high-viscosity second positive photoresist is coated on the first surface after the positioning marks are prepared; the second positive photoresist will completely cover the positioning marks on the first surface.

[0090] The substrate coated with the second positive photoresist was placed in an environment of 90℃~130℃ and baked for 5min~20min;

[0091] The baked substrate is placed in a photolithography machine for exposure and developed with a developer to form a second photoresist mask pattern.

[0092] The substrate with the second photoresist mask pattern is placed in an environment of 90℃~130℃ and baked for 5min~20min.

[0093] According to some embodiments of the present invention, depositing a second metal layer of thickness H on the first surface on which the second photoresist mask pattern is formed includes:

[0094] A Cr metal layer with a thickness of H1 and an Au metal layer with a thickness of H2 are sequentially deposited on the first surface on which the second photoresist mask pattern is prepared.

[0095] According to some embodiments of the present invention, H1 satisfies:

[0096] H2 satisfies:

[0097] The following reference Figures 3-6 The following describes in detail a method for fabricating an infrared detector splicing substrate according to an embodiment of the present invention, using a specific example. It is to be understood that the following description is merely illustrative and not intended to limit the scope of the invention. Any similar structures or variations thereof employing the present invention should be included within the scope of protection of the present invention.

[0098] To improve the processing accuracy of the positioning marks on the splicing substrate, thereby enhancing the splicing accuracy of the submodules, this invention proposes a method for fabricating an infrared detector splicing substrate. In this method, based on the requirements for pattern accuracy and metal film thickness of the positioning marks and metal leads, two processing techniques—dry etching and wet stripping—are combined to process the two patterns separately. This achieves the fabrication of high-precision positioning mark patterns and low-resistivity, thick-film metal lead patterns, while simultaneously meeting the requirements of high-performance detectors for splicing accuracy and electrical reliability.

[0099] Specifically, refer to Figure 3 The method for preparing an infrared detector splicing substrate according to an embodiment of the present invention includes:

[0100] Step 1: Clean the substrate.

[0101] For example, the substrate is immersed in deionized water, and ultrasonic cleaning is used to remove inorganic particle contaminants from the substrate surface. The substrate surface is then cleaned with acetone and ethanol in sequence to remove organic contaminants. Finally, high-purity dry nitrogen is used to purge the substrate surface to remove any residual ethanol reagent.

[0102] Step 2: Grow a first metal layer on the substrate surface.

[0103] A thin first metal layer with good adhesion to the substrate is grown on the cleaned splicing substrate to which the first metal layer is to be grown.

[0104] For example, 300 to 1000 angstroms of metallic Cr are deposited on the first surface of the substrate for positioning mark pattern preparation.

[0105] Step 3: Prepare the first photoresist mask pattern for dry etching.

[0106] For example, a 1-2 μm thick low-viscosity positive photoresist is coated onto the surface of a substrate containing metallic chromium (Cr). The substrate is then baked at 90°C to 130°C for 5-20 minutes, exposed in a photolithography machine, and developed with a developer. The substrate with the first photoresist mask is then baked at 90°C to 130°C for 5-20 minutes.

[0107] Step 4: Ion beam etching to create high-precision positioning marks.

[0108] For example, a substrate with the first photoresist mask pattern prepared is placed in an ion mill, with the surface of the substrate with the first photoresist mask pattern facing the ion source in the ion mill. The rotating substrate is etched under conditions of 250V to 500V beam voltage and 30mA to 120mA beam current until the metallic chromium not covered by the first photoresist mask pattern is completely removed from the substrate surface.

[0109] Step 5: Wet cleaning to remove the photolithography mask used for dry etching.

[0110] For example, the etched substrate is immersed in acetone until the first photoresist mask pattern dissolves. Then, the substrate is cleaned with fresh acetone and ethanol in sequence, and the substrate surface is purged with high-purity dry nitrogen to remove the residual ethanol reagent.

[0111] The process of steps 2-5 above can be referred to Figure 4 As shown, Figure 4 This is a schematic diagram illustrating the preparation of positioning markers in an embodiment of the present invention. Figure 4 In the diagram, number 1 represents the substrate, number 2 represents the first metal layer, and number 5 represents the first photoresist mask pattern.

[0112] Step 6: Prepare the second photoresist mask pattern for wet stripping.

[0113] A thick second photoresist mask pattern is fabricated on the same side surface of the substrate as the positioning marks. The relative positions of the second photoresist mask pattern are then determined using the etched positioning marks.

[0114] For example, a 4μm to 10μm high-viscosity second positive photoresist is coated on the same side surface of the substrate with the positioning mark pattern. The substrate is baked at 90°C to 130°C for 5 min to 20 min, and then the substrate is placed in a photolithography machine for exposure and developed with a developer.

[0115] Step 7: Deposit the second metal layer.

[0116] A thicker, low-resistivity metal film is grown on the same side surface of the substrate as the second photoresist mask pattern.

[0117] For example, 300 angstroms to 1,000 angstroms of metallic Cr and 8,000 angstroms to 15,000 angstroms of metallic Au are sequentially deposited on the same side surface of the substrate with the second photoresist mask pattern.

[0118] Step 8: Wet stripping to complete the fabrication of the metal leads.

[0119] A stripping process is used to remove the second photoresist mask pattern and the second metal layer on the outer surface of the second photoresist mask pattern from the substrate surface. The thick, low-resistivity second metal layer on the substrate surface without the thick photoresist mask pattern will be retained, thus completing the fabrication of the metal leads.

[0120] For example, the substrate is immersed in acetone until the photoresist mask dissolves, and the second metal layer deposited on the surface of the second photoresist mask pattern falls off the substrate surface. The substrate is then cleaned with fresh acetone and ethanol in sequence, and the substrate surface is purged with high-purity dry nitrogen to remove the residual ethanol reagent.

[0121] The process of steps 6-8 above can be referred to Figure 5 As shown, Figure 5 This is a schematic diagram of the metal lead fabrication in an embodiment of the present invention. Figure 5 In the diagram, number 1 represents the substrate, number 3 represents the second metal layer, and number 4 represents the second photoresist mask pattern.

[0122] Figure 6 This is a schematic diagram of the infrared detector splicing substrate prepared using the above method.

[0123] This invention, through designing different metal film thicknesses for the positioning mark patterns and metal lead patterns on the splicing substrate, employs a dry etching process for the positioning mark patterns and a stripping process for the metal lead patterns. This ultimately achieves the fabrication of high-quality positioning marks and low-resistance metal lead patterns. While meeting the current-carrying capacity requirements of the electrical lead structure, it improves the pattern processing accuracy of the splicing alignment marks, reduces the processing difficulty of the splicing substrate, and is beneficial for improving the splicing accuracy of the detector submodules.

[0124] It should be noted that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

[0125] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Although some embodiments described herein include certain features included in other embodiments but not others, combinations of features from different embodiments are intended to be within the scope of the invention and form different embodiments. Specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. For example, in the claims, any of the claimed embodiments may be used in any combination.

[0126] The terms “comprising,” “including,” or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase “comprising one…” does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0127] Any reference signs enclosed in parentheses should not be construed as limiting the claims. The word "a" or "an" preceding an element does not exclude the existence of a plurality of such elements. The use of the words first, second, and third, etc., does not indicate any order. These words may be interpreted as names.

Claims

1. A method for preparing an infrared detector splicing substrate, characterized in that, include: Clean the substrate; At least one positioning mark is prepared on the first surface of the cleaned substrate using a dry etching process. The positioning mark is a metal pattern with a thickness of h. At least one metal lead is prepared on the first surface after the positioning mark is prepared using a stripping process. The thickness of the metal lead is H, and the following condition is satisfied: H > h. The h satisfies: 300Å ≤ h ≤ 1000Å; The step of fabricating at least one metal lead on the first surface after the positioning mark is prepared includes: A second photoresist mask pattern is prepared on the first surface after the positioning marks are prepared; A second metal layer of thickness H is deposited on the first surface on which the second photoresist mask pattern is prepared; The substrate with the second metal layer deposited is immersed in acetone to dissolve the second photoresist mask pattern; The deposition of a second metal layer with a thickness of H on the first surface on which the second photoresist mask pattern is prepared includes: A Cr metal layer with a thickness of H1 and an Au metal layer with a thickness of H2 are sequentially deposited on the first surface on which the second photoresist mask pattern is prepared. H1 satisfies: 300Å ≤ H1 ≤ 1000Å; The H2 satisfies: 8000Å≤H2≤15000Å.

2. The method as described in claim 1, characterized in that, The step of preparing at least one positioning mark on the first surface of the cleaned substrate includes: A first metal layer of thickness h is deposited on the first surface of the cleaned substrate. A first photoresist mask pattern is prepared on the surface of the first metal layer; An etching process is used to remove the portion of the first metal layer that is not covered by the first photoresist mask pattern.

3. The method as described in claim 2, characterized in that, Fabricating a first photoresist mask pattern on the surface of the first metal layer includes: A low-viscosity positive photoresist with a thickness of 1 μm to 2 μm is coated on the surface of the first metal layer; The substrate coated with the first positive photoresist was placed in an environment of 90℃~130℃ and baked for 5min~20min; The baked substrate is placed in a photolithography machine for exposure and developed with a developer to form the first photoresist mask pattern; The substrate with the first photoresist mask pattern is placed in an environment of 90℃~130℃ and baked for 5min~20min.

4. The method as described in claim 2, characterized in that, The etching process for removing portions of the first metal layer not covered by the first photoresist mask pattern includes: The substrate with the first photoresist mask pattern prepared is placed in an ion milling machine with the first surface facing the ion source. Physical etching is performed using an ion current with a beam voltage of 250V to 500V and a beam current of 30mA to 120mA to remove the portion of the first metal layer not covered by the first photoresist mask pattern.

5. The method as described in claim 2, characterized in that, The step of preparing at least one positioning mark on the first surface of the cleaned substrate further includes: The first photoresist mask pattern is removed using a wet process.

6. The method as described in claim 1, characterized in that, The metal pattern is a Cr metal pattern.

7. The method as described in claim 1, characterized in that, The step of preparing a second photoresist mask pattern on the first surface after the positioning marks have been prepared includes: A second, highly viscous photoresist with a thickness of 4 μm to 10 μm is coated on the first surface after the positioning mark is prepared; The substrate coated with the second positive photoresist was placed in an environment of 90℃~130℃ and baked for 5min~20min; The baked substrate is placed in a photolithography machine for exposure and developed with a developer to form a second photoresist mask pattern. The substrate with the second photoresist mask pattern is placed in an environment of 90℃~130℃ and baked for 5min~20min.

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