A multi-layer MEMS structure, a manufacturing method thereof, and an application thereof

Abstract

The present invention provides a multi-layer MEMS structure, a manufacturing method thereof and an application. The manufacturing method includes the following steps: a first film covering and patterning step: covering a first photosensitive dry film on a substrate, and patterning the first photosensitive dry film to obtain a first cavity in the first photosensitive dry film; a second film covering and patterning step: covering a second photosensitive dry film on the first photosensitive dry film, and patterning the second photosensitive dry film to obtain a second cavity in the second photosensitive dry film. Wherein, if the required number of layers is more than two, the film covering and patterning steps can be continued at least once according to the required number of layers. The present invention uses at least two layers of photosensitive dry films to realize the manufacture of a multi-layer MEMS structure. Each layer structure is flatter and the exposure is more uniform, which can reduce the structural error, thereby improving the yield of the manufacture of the multi-layer MEMS structure. The multi-layer MEMS structure and the manufacturing method thereof can be applied to various microstructures, including but not limited to nanopore sequencing chips.

Description

Technical Field

[0001] The present invention belongs to the technical field of microelectromechanical system (MEMS) device processing, and relates to a multi-layer MEMS structure, a manufacturing method thereof, and an application thereof. Background Art

[0002] Microelectromechanical systems (MEMS) devices have the characteristics of miniaturization, intelligence, multi-function, high integration, and suitability for mass production. Their internal structures are generally in the micrometer or even nanometer scale and require ultra-precision machining. If the structural error is large, it will have an adverse impact on the device performance. Summary of the Invention

[0003] In view of the above-mentioned disadvantages of the prior art, the purpose of the present invention is to provide a multi-layer MEMS structure, a manufacturing method thereof, and an application thereof, which are used to solve the problem of large structural errors in the prior art MEMS structures.

[0004] To achieve the above purpose and other related purposes, the present invention provides a manufacturing method of a multi-layer MEMS structure, including the following steps:

[0005] The first film covering and patterning step: covering a first photosensitive dry film on a substrate, and patterning the first photosensitive dry film to obtain a first cavity in the first photosensitive dry film;

[0006] The second film covering and patterning step: covering a second photosensitive dry film on the first photosensitive film, and patterning the second photosensitive dry film to obtain a second cavity in the second photosensitive dry film.

[0007] Optionally, continue to perform the film covering and patterning step at least once to obtain at least three layers of patterned photosensitive dry films stacked on the substrate from bottom to top.

[0008] Optionally, the film covering is completed by a manual or / and automatic film laminator.

[0009] Optionally, during each film covering process or after each film covering, heat the substrate to a preset temperature and apply a preset pressure on the surface of the covered photosensitive dry film.

[0010] Optionally, the range of the preset temperature is 40°C to 90°C, the range of the preset pressure is 2 kPa to 10 kPa, and the duration of applying the preset pressure is 1 minute to 10 minutes.

[0011] Optionally, the patterning includes an ultraviolet light irradiation exposure step, a post-exposure baking step, and a development step.

[0012] Optionally, the thickness range of the first photosensitive dry film or the second photosensitive dry film is 5 micrometers to 1000 micrometers.

[0013] Optionally, the second cavity communicates with the first cavity.

[0014] Optionally, the opening area of the second cavity is greater than or less than the opening area of the first cavity.

[0015] Optionally, an electrode layer is provided on the surface of the substrate, and the first cavity exposes the electrode layer.

[0016] Optionally, before performing the first film coating and patterning steps, the surface of the substrate is cleaned.

[0017] The present invention also provides an application of a multi-layer MEMS structure in a nanopore sequencing chip. The multi-layer MEMS structure is fabricated by using the fabrication method of the MEMS structure described in any one of the above. The nanopore sequencing chip includes a sample cavity, a phospholipid layer, and a protein nanopore. The first cavity and the second cavity serve as components of the sample cavity. The phospholipid layer is fixed to the inner wall of the sample cavity and is suspended in the sample cavity. The protein nanopore is connected to the phospholipid layer and penetrates the phospholipid layer in the vertical direction.

[0018] The present invention also provides a multi-layer MEMS structure, comprising:

[0019] A substrate;

[0020] At least two layers of photosensitive dry films are stacked on the substrate in sequence from bottom to top, and cavities are provided in the photosensitive dry films.

[0021] Optionally, the thickness range of the photosensitive dry film is 5 micrometers to 1000 micrometers.

[0022] Optionally, the opening areas of the cavities in adjacent two layers of the photosensitive dry films are different.

[0023] Optionally, an electrode layer is provided on the surface of the substrate, and the cavity in the photosensitive dry film at the bottom layer exposes the electrode layer.

[0024] The present invention also provides an application of a multi-layer MEMS structure in a nanopore sequencing chip. The multi-layer MEMS structure adopts the multi-layer MEMS structure described in any one of the above. The nanopore sequencing chip includes a sample cavity, a phospholipid layer, and a protein nanopore. The cavities in each layer of the photosensitive dry films serve as components of the sample cavity. The phospholipid layer is fixed to the inner wall of the sample cavity and is suspended in the sample cavity. The protein nanopore is connected to the phospholipid layer and penetrates the phospholipid layer in the vertical direction.

[0025] As described above, the multi-layer MEMS structure and its manufacturing method of the present invention use at least two layers of photosensitive dry film to realize the manufacturing of the multi-layer MEMS structure. Each layer structure is flatter and the exposure is more uniform, which can reduce the structural error, thereby improving the yield of the manufacturing of the multi-layer MEMS structure. The multi-layer MEMS structure and its manufacturing method can be applied to various microstructures, including but not limited to nanopore sequencing chips. Description of the Drawings

[0026] Figure 1 It shows a process flow chart of the manufacturing method of the multi-layer MEMS structure of the present invention.

[0027] Figure 2 It shows a schematic diagram of the first film coating and patterning step performed by the manufacturing method of the multi-layer MEMS structure of the present invention.

[0028] Figure 3 It shows a schematic diagram of the second film coating and patterning step performed by the manufacturing method of the multi-layer MEMS structure of the present invention.

[0029] Figure 4 It shows Figure 3 a top view of the structure shown.

[0030] Figure 5 It shows a cross-sectional view of the multi-layer MEMS structure fabricated in another embodiment.

[0031] Figure 6 It shows Figure 5 a top view of the structure shown.

[0032] Figure 7 It shows a design and manufacturing flow chart of a multi-layer MEMS structure.

[0033] Figure 8 It shows a schematic cross-sectional structure diagram of a nanopore sequencing chip using the multi-layer MEMS structure as a support structure.

[0034] Description of Component Labels

[0035] Steps S1 to S2

[0036] 1 Substrate

[0037] 2 First photosensitive dry film

[0038] 3 First cavity

[0039] 4 Second photosensitive dry film

[0040] 401 Suspended part

[0041] 5 Second cavity

[0042] 6 Phospholipid layer

[0043] 7 Protein nanopore

[0044] 8 Electrode layer Detailed implementation manners

[0045] The following uses specific specific examples to illustrate the implementation manners 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 implementation manners. 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.

[0046] Please refer to Figures 1 to 8 . It should be noted that the illustrations provided in this embodiment only illustrate the basic concept of the present invention in a schematic manner. Therefore, only the components related to the present invention are shown in the drawings, rather than being drawn according to the number, shape, and size of the components during actual implementation. The type, quantity, and ratio of each component during actual implementation can be arbitrarily changed, and the component layout type may also be more complex.

[0047] Embodiment 1

[0048] In this embodiment, a manufacturing method of a multi-layer MEMS structure is provided. Please refer to Figure 1 , which shows the process flow chart of this method, including the following steps:

[0049] S1: The first film covering and patterning step: Cover a first photosensitive dry film on the substrate, pattern the first photosensitive dry film, and obtain a first cavity in the first photosensitive dry film;

[0050] S2: The second film covering and patterning step: Cover a second photosensitive dry film on the first photosensitive film, pattern the second photosensitive dry film, and obtain a second cavity in the second photosensitive dry film.

[0051] First, please refer to Figure 2 , and execute step S1: The first film covering and patterning step: Cover a first photosensitive dry film 2 on the substrate 1 through a manual or / and automatic film laminator, pattern the first photosensitive dry film 2, and obtain a first cavity 3 in the first photosensitive dry film 2.

[0052] Specifically, the substrate 1 serves as a support platform and can be made of any suitable material such as a silicon wafer, a peeled layer, a polymer material layer, etc. Before performing the first film lamination and patterning steps, the surface of the substrate 1 can be cleaned by chemical or physical methods. The thickness of the first photosensitive dry film 2 can be selected as needed, for example, it can be 5 microns to 1000 microns. According to the type of the dry film, the substrate can be heated to 40°C to 90°C to soften the dry film. And a certain pressure can be applied according to the substrate area, for example, 2 kPa to 10 kPa, to assist in film lamination, and the duration can be 1 - 10 minutes. The patterning can include an ultraviolet light irradiation exposure step, a post-exposure baking step, and a developing step. In this embodiment, after patterning the first photosensitive dry film 2, the patterned first photosensitive dry film 2 can be further baked and cured. The shape of the first cavity 3 can be adjusted as needed.

[0053] As an example, an electrode layer ( Figure 2 not shown in the figure, see the following Figure 8 ) can be pre-fabricated on the surface of the substrate 1. The first cavity 3 exposes the electrode layer, and the electrode layer can include one or more conductive metal layers.

[0054] Then refer to Figure 3 , and perform step S2: the second film lamination and patterning step: cover the second photosensitive dry film 4 on the first photosensitive film 2 through a manual or / and automatic film laminator, and pattern the second photosensitive dry film 4 to obtain a second cavity 5 in the second photosensitive dry film 4.

[0055] Specifically, the thickness of the second photosensitive dry film 4 can be selected as needed, for example, it can be 5 microns to 1000 microns. According to the type of the dry film, the substrate can be heated to 40°C to 90°C to soften the dry film. And a certain pressure can be applied according to the substrate area, for example, 2 kPa to 10 kPa, to assist in film lamination, and the duration can be 1 - 10 minutes. The patterning can include an ultraviolet light irradiation exposure step, a post-exposure baking step, and a developing step. In this embodiment, after patterning the second photosensitive dry film 4, the patterned dry film can be further baked and cured. The shape of the second cavity 5 can be adjusted as needed.

[0056] Please refer to Figure 4 , which shows a top view of the structure shown in Figure 3 . In this embodiment, the second cavity 5 communicates with the first cavity 3, and the opening area of the second cavity 5 is larger than the opening area of the first cavity 3.

[0057] Please refer to Figure 5 and Figure 6 , where Figure 5Shown is a cross-sectional view of the MEMS structure fabricated in another embodiment. Figure 6 Shown as Figure 5 a top view of the structure shown, in this embodiment, the opening area of the second cavity 5 is smaller than the opening area of the first cavity 3, and a part of the second photosensitive dry film 4 is suspended above the first cavity 3, wherein Figure 6 the suspended portion 401 of the second photosensitive dry film 4 is marked.

[0058] Thus, a multi-layer MEMS structure including two layers of photosensitive dry film is fabricated. In other embodiments, the film coating and patterning steps can be continued at least once as needed to obtain at least three layers (e.g., 3 - 10 layers, or more) of patterned photosensitive dry film stacked on the substrate from bottom to top. Please refer to Figure 7 which shows a design and fabrication flow chart of a multi-layer MEMS structure, including the following process steps:

[0059] (1) Determine the number of layers of the MEMS structure and the lithography process conditions for each layer;

[0060] (2) Clean the substrate;

[0061] (3) Perform dry film coating using manual or automatic methods;

[0062] (4) Pattern the coated dry film;

[0063] (5) Bake and cure the patterned dry film;

[0064] (6) Repeat steps (2) - (5) at least once to complete the MEMS structure of the corresponding number of layers.

[0065] Specifically, each of the above-mentioned film coatings can be completed by a manual or / and automatic film laminator. The thickness of each layer of photosensitive dry film can be adjusted as needed, and the thicknesses of different layers can be the same or different. According to the type of dry film, during each film coating process or after each film coating, the substrate can be heated to a preset temperature, and a preset pressure can be applied to the surface of the covered photosensitive dry film to assist in film coating.

[0066] The multi-layer MEMS structure fabricated in this embodiment can be applied to various microstructures. Here, taking its application to a nanopore sequencing chip as an example for illustration. Currently, there are mainly three common sequencing products on the market, which are respectively based on the 2nd, 3rd, and 4th generation sequencing technologies. The chip of the second-generation sequencing technology is fabricated by processing a circular groove array on glass and modifying the DNA fragments for sequencing in the groove array. The chip of the third-generation sequencing technology is to process nano-scale micropores on metal through semiconductor processes. The chip of the fourth-generation sequencing technology is to use photoresist to process the support structure of protein nanopores through semiconductor processes. Among them, the fourth-generation sequencing technology is also known as nanopore sequencing technology. The basic working principle of a nanopore is that in a cavity filled with electrolyte solution, an insulating and anti-leakage membrane with a nano-scale pore divides the cavity into two small chambers. When a voltage is applied to the electrolyte chamber, ions or other small molecule substances can pass through the pore, forming a stable and detectable ionic current. By mastering the size and surface characteristics of the nanopore, the applied voltage, and the solution conditions, different types of biomolecules can be detected. Since the molecular structures and volumes of the four bases adenine (A), guanine (G), cytosine (C), and thymine (T) that make up DNA are all different, single-stranded DNA (ssDNA) is rapidly cut into deoxyribonucleotide molecules one by one under the action of exonuclease. When a single base passes through the nano-scale pore driven by an electric field, the different chemical properties of different bases result in different amplitudes of current changes when passing through the nanopore, thereby obtaining the sequence information of the measured DNA.

[0067] In the chip of the fourth-generation sequencing technology, the main function of the support structure is to form a phospholipid layer to fix the protein nanopore. This support structure is generally composed of multiple layers. Please refer to Figure 8 , which shows a schematic cross-sectional structure diagram of a nanopore sequencing chip using the above fabricated multi-layer MEMS structure as the support structure ( Figure 8 only two layers of photosensitive dry film are schematically shown. In actual applications, the number of layers of the photosensitive dry film can be more than two). The nanopore sequencing chip includes a sample cavity, a phospholipid layer 6, and a protein nanopore 7. The first cavity 3 surrounded by the first photosensitive dry film 2 and the second cavity 5 surrounded by the second photosensitive dry film 4 of the MEMS structure are used as components of the sample cavity. The phospholipid layer 6 is fixed to the inner wall of the sample cavity, that is, supported by the photosensitive dry film and suspended in the sample cavity, dividing the sample cavity into upper and lower parts. The protein nanopore 7 is connected to the phospholipid layer 6 and penetrates the phospholipid layer 6 in the vertical direction. That is to say, the protein nanopore 7 is embedded in the phospholipid layer 6. In this embodiment, an electrode layer 8 is provided at the bottom of the sample cavity, which serves as an electrode of the test circuit. By measuring the current change during the passage of DNA through the protein nanopore and decoding the current information, it can be determined which base has passed through.

[0068] When fabricating a structure with a relatively large thickness using a liquid photoresist, the film layer will be uneven due to spin coating, which will in turn cause unevenness during contact exposure, resulting in a large structural error in the end. In this embodiment, at least two layers of photosensitive dry films are used to manufacture a multi-layer MEMS structure. The structures of each layer are flatter, the exposure is more uniform, the structural error can be reduced, and thus the yield of manufacturing the multi-layer MEMS structure can be improved. The fabricated multi-layer MEMS structure can be applied to various microstructures, including but not limited to nanopore sequencing chips.

[0069] Embodiment 2

[0070] In this embodiment, a multi-layer MEMS structure is provided, which includes a substrate and at least two layers of photosensitive dry films stacked on the substrate in sequence from bottom to top. Cavities are provided in the photosensitive dry films.

[0071] As an example, the thickness range of the photosensitive dry film is 5 microns to 1000 microns. The thickness of each layer of the photosensitive dry film can be adjusted as needed, and the thicknesses of different layers can be the same or different.

[0072] As an example, the opening areas of the cavities in two adjacent layers of the photosensitive dry films are different.

[0073] As an example, an electrode layer is provided on the surface of the substrate, and the cavity in the photosensitive dry film located at the bottom layer exposes the electrode layer.

[0074] The multi-layer MEMS structure of this embodiment can be applied to various microstructures, including but not limited to nanopore sequencing chips. As an example, the nanopore sequencing chip includes a sample cavity, a phospholipid layer, and a protein nanopore. The cavities in each layer of the photosensitive dry film serve as part of the sample cavity. The phospholipid layer is fixed to the inner wall of the sample cavity and suspended in the sample cavity. The protein nanopore is connected to the phospholipid layer and penetrates the phospholipid layer in the vertical direction.

[0075] In summary, the multi-layer MEMS structure and its manufacturing method of the present invention use at least two layers of photosensitive dry films to manufacture the multi-layer MEMS structure. The multi-layer MEMS structure includes at least two layers of photosensitive dry films. The structures of each layer are flatter, the exposure is more uniform, the structural error can be reduced, and thus the yield of manufacturing the multi-layer MEMS structure can be improved. The multi-layer MEMS structure and its manufacturing method can be applied to various microstructures, including but not limited to nanopore sequencing chips. Therefore, the present invention effectively overcomes various disadvantages in the prior art and has high industrial utilization value.

[0076] The above embodiments are only illustrative of the principles and effects of the present invention and are not intended to limit the present invention. Any person familiar with this technology can modify or change the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by those with ordinary knowledge in the technical field without departing from the spirit and technical idea disclosed by the present invention should still be covered by the claims of the present invention.

Claims

1. Application of a multi-layer MEMS structure in a nanopore sequencing chip, characterized in that: The multi-layer MEMS structure is fabricated by using the fabrication method of the multi-layer MEMS structure described below; the nanopore sequencing chip includes a sample chamber, a phospholipid layer, and a protein nanopore; The fabrication method of the multi-layer MEMS structure includes the following steps: The first film coating and patterning step: Cover a first photosensitive dry film on the substrate, pattern the first photosensitive dry film, and obtain a first cavity in the first photosensitive dry film; The second film coating and patterning step: Cover a second photosensitive dry film on the first photosensitive dry film, pattern the second photosensitive dry film, and obtain a second cavity in the second photosensitive dry film; The second cavity communicates with the first cavity; The opening area of the second cavity is larger or smaller than the opening area of the first cavity; An electrode layer is provided on the surface of the substrate, and the first cavity exposes the electrode layer; The first cavity and the second cavity serve as components of the sample chamber, the phospholipid layer is fixed to the inner wall of the sample chamber and is suspended in the sample chamber, and the protein nanopore is connected to the phospholipid layer and penetrates through the phospholipid layer in the vertical direction.

2. The application according to claim 1, wherein: Continue to perform the film coating and patterning step at least once to obtain at least three layers of patterned photosensitive dry films stacked on the substrate in sequence from bottom to top.

3. The application according to claim 1, characterized in that: The film coating is completed by a manual or / and automatic film laminator.

4. The application according to claim 1, characterized in that: During each film coating process or after each film coating, heat the substrate to a preset temperature and apply a preset pressure on the surface of the covered photosensitive dry film.

5. The application according to claim 4, characterized in that: The range of the preset temperature is 40°C to 90°C, the range of the preset pressure is 2 kPa to 10 kPa, and the duration of applying the preset pressure is 1 minute to 10 minutes.

6. The application according to claim 1, characterized in that: The patterning includes an ultraviolet light irradiation exposure step, a post-exposure baking step, and a developing step.

7. The application according to claim 1, characterized in that: The thickness range of the first photosensitive dry film or the second photosensitive dry film is 5 micrometers to 1000 micrometers.

8. The application according to claim 1, wherein: Before performing the first film coating and patterning step, clean the surface of the substrate.

9. Application of a multi-layer MEMS structure in a nanopore sequencing chip, characterized in that: The nanopore sequencing chip includes a sample chamber, a phospholipid layer, and a protein nanopore; The multi-layer MEMS structure includes: A substrate; At least two layers of photosensitive dry films stacked on the substrate in sequence from bottom to top, and cavities are provided in the photosensitive dry films; The cavities in each layer of the photosensitive dry films serve as components of the sample chamber, the phospholipid layer is fixed to the inner wall of the sample chamber and is suspended in the sample chamber, and the protein nanopore is connected to the phospholipid layer and penetrates through the phospholipid layer in the vertical direction; The opening areas of the cavities in two adjacent layers of the photosensitive dry films are different; An electrode layer is provided on the surface of the substrate, and the cavity in the photosensitive dry film at the bottom layer exposes the electrode layer.

10. The application according to claim 9, characterized in that: The thickness range of the photosensitive dry film is 5 micrometers to 1000 micrometers.

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