Preparation method of sheath type flexible neural electrode and sheath type flexible neural electrode

Abstract

The invention provides a preparation method of a sheath type flexible neural electrode and the sheath type flexible neural electrode. The preparation method comprises the following steps: providing a substrate layer; sequentially forming a bottom sacrificial layer, a flexible substrate layer, a middle sacrificial layer, a flexible middle layer, an interconnection layer and a flexible protection layer on the substrate layer; forming an electrode layer, wherein the electrode layer is in contact with the interconnection layer; removing the intermediate sacrificial layer to form a space in the flexible intermediate layer; and removing the substrate layer and the bottom sacrificial layer. The nerve electrode is of a sheath type structure, the implantation needle can stretch into the space of the nerve electrode, the nerve electrode wraps the implantation needle, and therefore the implantation needle cannot make contact with tissue in the implantation process. In addition, the sheath type structure avoids the use of a sharp implantation needle and can use an implantation needle with a blunt end, which is beneficial to reducing the damage to the tissue.

Description

Technical Field

[0001] The present application mainly relates to the technical field of flexible neural electrodes, and in particular to a preparation method of a sheath-type flexible neural electrode and a sheath-type flexible neural electrode. Background Art

[0002] Flexible neural electrodes are an emerging means of detecting neural activity. Because their electrodes use flexible polymer materials as insulating layers, they have mechanical properties closer to those of neural tissues, better biocompatibility, and can build a more stable electrode-nerve interface to obtain higher-quality neural signals. They have great application potential in the development and application of brain-computer interface technology. Since neural electrodes are relatively soft, it is difficult for them to penetrate tissues such as the dura mater by relying on their own properties, and they cannot be directly implanted into brain tissues. Therefore, various tools such as metal needles and syringes are needed to assist in the implantation operation. These auxiliary devices usually require a sharp front end to penetrate the tissue, which may puncture large blood vessels during the implantation process, causing severe damage and affecting the recording and stimulation performance of the electrode. In addition, the exposed guide needle or syringe, etc., which is in direct contact with the tissue during the implantation process, will also have an adverse effect on the electrode-nerve interface. Therefore, how to prevent neural electrodes from damaging tissues during implantation is a hot issue in this field. Summary of the invention

[0003] The technical problem to be solved by the present application is to provide a method for preparing a sheath-type flexible neural electrode and a sheath-type flexible neural electrode, which can prevent the sharp implantation needles of the neural electrode from causing damage to the tissue during the implantation process.

[0004] To solve the above technical problems, the present application provides a method for preparing a sheath-type flexible neural electrode, comprising: providing a substrate layer; sequentially forming a bottom sacrificial layer, a flexible base layer, an intermediate sacrificial layer, a flexible intermediate layer, an interconnection layer and a flexible protective layer on the substrate layer; forming an electrode layer, the electrode layer being in contact with the interconnection layer; removing the intermediate sacrificial layer to form a space in the flexible intermediate layer; and removing the substrate layer and the bottom sacrificial layer.

[0005] In one embodiment of the present application, the step of forming the space includes: forming an intermediate sacrificial layer on the flexible base layer, the intermediate sacrificial layer covering a local area of ​​the flexible base layer; forming an opening passing through the substrate layer, the bottom sacrificial layer and the flexible base layer, the opening exposing the intermediate sacrificial layer; and etching away the intermediate sacrificial layer through the opening to form the space.

[0006] In one embodiment of the present application, the intermediate sacrificial layer is formed by the following method one or method two: method one: forming a first patterned mask on the flexible base layer by spin coating photoresist, baking, exposing and developing, forming the intermediate sacrificial layer on the flexible base layer exposed by the first patterned mask, and removing the first patterned mask; method two: forming the intermediate sacrificial layer on the flexible base layer by an etching process.

[0007] In one embodiment of the present application, the step of forming the opening includes: forming a protective glue on the flexible protective layer; flipping the neural electrode; forming a second patterned mask on the back side of the substrate layer; etching the substrate layer exposed by the second patterned mask to form the opening; and removing the second patterned mask and the protective glue.

[0008] In an embodiment of the present application, a wet etching process is used to remove the bottom sacrificial layer and the middle sacrificial layer.

[0009] In one embodiment of the present application, the flexible base layer has a connection hole, and a portion of the flexible intermediate layer is embedded in the connection hole to increase the bonding force between the flexible base layer and the flexible intermediate layer.

[0010] In one embodiment of the present application, the step of forming the connecting hole includes: forming a sixth patterned mask on the flexible base layer by spin coating, baking, exposure and development; etching the flexible base layer exposed by the sixth patterned mask to form the connecting hole; and removing the sixth patterned mask.

[0011] In one embodiment of the present application, the step of forming the bottom sacrificial layer includes: forming a third patterned mask on the substrate layer by spin coating photoresist, baking, exposing and developing; forming a bottom sacrificial layer on the substrate layer exposed by the third patterned mask; and removing the third patterned mask.

[0012] In one embodiment of the present application, the flexible base layer includes a polymer flexible material, wherein the polymer flexible material includes any one of polyimide, polydimethylsiloxane, silicone rubber, SU-8 photoresist negative resist, and polyparaxylene.

[0013] In one embodiment of the present application, the flexible intermediate layer is formed by spin coating, baking curing or physical vapor deposition, and / or the flexible protective layer is formed by spin coating, baking curing or physical vapor deposition, and the flexible protective layer wraps the interconnection layer, wherein the flexible intermediate layer and the flexible protective layer include a polymer flexible material, and the polymer flexible material includes any one of polyimide, polydimethylsiloxane, silicone rubber, SU-8 photoresist negative resin, and polyparaxylene.

[0014] In one embodiment of the present application, the step of forming the interconnection layer includes: forming a fourth patterned mask on the flexible intermediate layer by spin coating photoresist, baking, exposing and developing; forming the interconnection layer on the flexible intermediate layer exposed by the fourth patterned mask; and removing the fourth patterned mask.

[0015] In one embodiment of the present application, it also includes contour etching, which includes the steps of: forming a fifth patterned mask on the flexible protective layer by spin coating photoresist, baking, exposing and developing; etching the film layer not covered by the fifth patterned mask to form a neural electrode with a preset contour; and removing the fifth patterned mask.

[0016] In one embodiment of the present application, the step of forming the electrode layer includes: forming a sixth patterned mask on the flexible protective layer by spin coating photoresist, baking, exposing and developing; removing the flexible protective layer exposed by the sixth patterned mask to expose the interconnection layer; forming the electrode layer on the exposed interconnection layer; and removing the sixth patterned mask.

[0017] On the other hand, the present application also proposes a sheath-type flexible neural electrode, comprising: a flexible base layer, a flexible intermediate layer, an interconnection layer and a flexible protective layer arranged in a stacked manner; an electrode layer, which passes through the flexible protective layer and contacts the interconnection layer; and a space, which is located in the flexible intermediate layer.

[0018] On the other hand, the present application also proposes a sheath-type flexible neural electrode, which is prepared by the preparation method as described above.

[0019] Compared with the prior art, the present application has the following advantages: the neural electrode of the present application has a sheath structure, the implantation needle can be inserted into the space of the neural electrode, and the neural electrode wraps the implantation needle, so that during the implantation process, the implantation needle will not contact the tissue. In addition, the sheath structure avoids the use of a sharp implantation needle, and a blunt-tipped implantation needle can be used, which is conducive to reducing damage to tissues (such as blood vessels). BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The accompanying drawings are included to provide a further understanding of the present application. They are included and constitute a part of the present application. The accompanying drawings illustrate embodiments of the present application and together with the present specification serve to explain the principles of the present application. In the accompanying drawings:

[0021] Figure 1 It is a schematic flow chart of a method for preparing a sheath-type flexible neural electrode in one embodiment of the present application;

[0022] Figures 2 to 4 is a cross-sectional schematic diagram of a sheath-type flexible neural electrode during the process of preparing the sheath-type flexible neural electrode in one embodiment of the present application;

[0023] Figure 5 It is a schematic top view of a sheath-type flexible neural electrode in one embodiment of the present application.

[0024] Reference numerals

[0025] Substrate layer 210 Flexible protective layer 260

[0026] Bottom sacrificial layer 220 Electrode layer 270

[0027] Flexible base layer 230 Space 280

[0028] Connection hole 231 Intermediate sacrificial layer 290

[0029] Flexible middle layer 240 opening 310

[0030] Interconnect layer 250 DETAILED DESCRIPTION

[0031] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for the description of the embodiments. Obviously, the drawings described below are only some examples or embodiments of the present application. For ordinary technicians in this field, the present application can also be applied to other similar scenarios based on these drawings without creative work. Unless it is obvious from the language environment or otherwise explained, the same reference numerals in the figures represent the same structure or operation.

[0032] As shown in this application and claims, unless the context clearly indicates an exception, the words "a", "an", "an" and / or "the" do not refer to the singular and may also include the plural. Generally speaking, the terms "include" and "comprise" only indicate the inclusion of the steps and elements that have been clearly identified, and these steps and elements do not constitute an exclusive list. The method or device may also include other steps or elements.

[0033] Unless otherwise specifically stated, the relative arrangement, numerical expressions and numerical values ​​of the parts and steps set forth in these embodiments do not limit the scope of the present application. At the same time, it should be understood that, for ease of description, the sizes of the various parts shown in the accompanying drawings are not drawn according to the actual proportional relationship. The technology, method and equipment known to those of ordinary skill in the relevant field may not be discussed in detail, but in appropriate cases, the technology, method and equipment should be considered as a part of the authorization specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters represent similar items in the following drawings, so that once a certain item is defined in an accompanying drawing, it does not need to be further discussed in subsequent drawings.

[0034] In the description of the present application, it should be understood that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "lateral, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the device or element referred to must have a specific direction or be constructed and operated in a specific direction, and therefore cannot be understood as limiting the scope of protection of the present application; the directional words "inside and outside" refer to the inside and outside relative to the contours of each component itself.

[0035] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used here to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0036] In addition, it should be noted that the use of words such as "first" and "second" to define components is only for the convenience of distinguishing the corresponding components. If not otherwise stated, the above words have no special meaning and cannot be understood as limiting the scope of protection of this application. In addition, although the terms used in this application are selected from well-known and commonly used terms, some terms mentioned in the specification of this application may be selected by the applicant at his or her discretion, and their detailed meanings are explained in the relevant parts of the description of this article. In addition, it is required to understand this application not only by the actual terms used, but also by the meaning implied by each term.

[0037] Flowcharts are used in the present application to illustrate the operations performed by the system according to the embodiments of the present application. It should be understood that the preceding or following operations are not necessarily performed accurately in order. On the contrary, various steps may be processed in reverse order or simultaneously. At the same time, other operations may be added to these processes, or one or more operations may be removed from these processes.

[0038] Next, the preparation method of the sheath-type flexible neural electrode and the sheath-type flexible neural electrode of the present application are described through examples.

[0039] refer to Figure 1 As shown, Figure 1 The preparation method in the embodiment includes the following steps S110 to S150.

[0040] S110: providing a substrate layer;

[0041] S120: forming a bottom sacrificial layer, a flexible base layer, an intermediate sacrificial layer, a flexible intermediate layer, an interconnection layer and a flexible protective layer in sequence on the substrate layer;

[0042] S130: forming an electrode layer, wherein the electrode layer is in contact with the interconnection layer;

[0043] S140: removing the middle sacrificial layer to form a space in the flexible middle layer;

[0044] S150: removing the substrate layer and the bottom sacrificial layer.

[0045] Next, steps S110 to S150 are described in detail.

[0046] refer to Figure 2 As shown, in step S110, a substrate layer 210 is provided, and the substrate layer 210 may be a hard film layer such as a silicon wafer.

[0047] Continue to refer Figure 2 As shown, in step S120, a bottom sacrificial layer 220, a flexible base layer 230, an intermediate sacrificial layer 290, a flexible intermediate layer 240, an interconnection layer 250 and a flexible protective layer 260 are sequentially formed on the substrate layer 210. Specifically, the interconnection layer 250 is formed on a local area of ​​the flexible intermediate layer 240, and the flexible protective layer 260 covers the interconnection layer 250 and the area of ​​the flexible intermediate layer 240 not covered by the interconnection layer 250.

[0048] In one embodiment, the bottom sacrificial layer 220 may be formed by the following steps:

[0049] Step S310: forming a third patterned mask on the substrate layer 210 by spin coating photoresist, baking, exposing and developing.

[0050] Step S320: forming a bottom sacrificial layer 220 on the substrate layer 210 exposed by the third patterned mask. It is understood that the bottom sacrificial layer 220 is in contact with the substrate layer 210 exposed by the third patterned mask. The material of the bottom sacrificial layer 220 may include one or more of Al, Ti, Ni, and Cr, and the bottom sacrificial layer 220 including the above materials may be formed by electron beam evaporation or magnetron sputtering. The bottom sacrificial layer 220 may also include polyparaxylene.

[0051] Step S330: removing the third patterned mask. The third patterned mask may be removed by a stripping process.

[0052] In one embodiment, the flexible base layer 230 includes a polymer flexible material, and the polymer flexible material may include any of polyimide, polydimethylsiloxane, silicone rubber, SU-8 photoresist, and polyparaxylene. It should be noted that when the flexible base layer 230 includes a polymer flexible material, the polymer flexible material may not include the above specific materials, and may also be other polymer flexible materials. The flexible base layer 230 may be formed by spin coating and baking curing.

[0053] In one embodiment, the flexible intermediate layer 240 can be formed by spin coating, baking curing or physical vapor deposition. The flexible intermediate layer 240 may include a polymer flexible material. The polymer flexible material may include any of polyimide, polydimethylsiloxane, silicone rubber, SU-8 photoresist negative resin, and polyparaxylene. It should be noted that "any type" includes zero, that is, when the flexible intermediate layer 240 includes a polymer flexible material, the polymer flexible material may not include the above-mentioned specific materials, and may also be other polymer flexible materials.

[0054] In one embodiment, the flexible protective layer 260 may be formed by spin coating, baking curing or physical vapor deposition, and the flexible protective layer 260 wraps the interconnection layer 250 to play an insulating and protective role. The flexible protective layer 260 may include any of polyimide, polydimethylsiloxane, silicone rubber, SU-8 photoresist negative resist, and polyparaxylene. It should be noted that "any" includes zero, that is, when the flexible protective layer 260 includes a polymer flexible material, the polymer flexible material may not include the above-mentioned specific materials, and may also be other polymer flexible materials.

[0055] refer to Figure 2 As shown, in one embodiment, the flexible base layer 230 has a connection hole 231, and a portion of the flexible intermediate layer 240 is embedded in the connection hole 231, so that the bonding force between the flexible base layer 230 and the flexible intermediate layer 240 can be increased. It is understood that the number and arrangement of the connection holes 231 are not limited to Figure 2 and Figure 5 As shown in , it can be set according to needs.

[0056] In one embodiment, the step of forming the connection hole 231 includes: spin coating photoresist on the flexible base layer 230, then baking the photoresist and exposing and developing the photoresist to form a sixth patterned mask; etching the flexible base layer 230 exposed by the sixth patterned mask to form the connection hole 231; and removing the sixth patterned mask. The connection hole 231 may penetrate the flexible base layer 230 or may not penetrate the flexible base layer 230.

[0057] In one embodiment, the step of forming the interconnect layer 250 includes:

[0058] S410 : forming a fourth patterned mask on the flexible intermediate layer 240 by spin coating photoresist, baking, exposing and developing. The fourth patterned mask exposes a portion of the flexible intermediate layer 240 .

[0059] S420: forming an interconnection layer 250 on the flexible intermediate layer 240 exposed by the fourth patterned mask. The interconnection layer 250 may include one or more of Au, Pt, Ti, Ni, and Cr, and may be formed by electron beam evaporation or magnetron sputtering.

[0060] S430: removing the fourth patterned mask. The fourth patterned mask may be removed by a stripping process.

[0061] It can be understood that the method of forming the interconnection layer 250 is not limited to the above-mentioned steps S140 to S430, and may also be other known methods.

[0062] Continue to refer Figure 2 As shown, in step S130 , an electrode layer 270 is formed, the electrode layer 270 penetrates the flexible protective layer 260 and contacts the interconnection layer 250 , and the electrode layer 270 is electrically connected to the interconnection layer 250 .

[0063] In one embodiment, the step of forming the electrode layer 270 includes:

[0064] S510 : forming a sixth patterned mask on the flexible protective layer 260 by spin coating photoresist, baking, exposing and developing. The sixth patterned mask exposes a portion of the flexible protective layer 260 .

[0065] S520 : removing the flexible protective layer exposed by the sixth patterned mask to expose the interconnection layer 250 . Etching the flexible protective layer exposed by the sixth patterned mask under the protection of the sixth patterned mask to form an opening in the flexible protective layer 260 to expose the interconnection layer 250 .

[0066] S530: forming an electrode layer 270 on the exposed interconnect layer 250. Preferably, the material of the electrode layer 270 is a material with high biocompatibility, such as Au, IrO x The electrode layer 270 may be formed by beamlet evaporation or magnetron sputtering.

[0067] S540: removing the sixth patterned mask. The sixth patterned mask may be removed by a stripping process.

[0068] refer to Figures 2 to 4 As shown, in step S140, the middle sacrificial layer 290 is removed to form a space 280 in the flexible middle layer 240. Figure 4In the embodiment, the space 280 is in the shape of a long strip, the nerve electrode has a sheath structure, the implantation needle can be inserted into the space 280, and the nerve electrode wraps the implantation needle, so that during the implantation process, the implantation needle will not contact the tissue. In addition, the sheath structure avoids the use of a sharp implantation needle, and a blunt-tipped implantation needle can be used, which is conducive to reducing damage to tissues (such as blood vessels).

[0069] refer to Figure 2 and Figure 5 As shown, from a top view, the connection holes 231 are distributed around the space 280 , which can increase the strength of the space 280 .

[0070] refer to Figures 2 to 4 As shown, the space 280 can be formed by the following steps S610 to S630:

[0071] S610 : forming an intermediate sacrificial layer 290 on the flexible base layer 230 , wherein the intermediate sacrificial layer 290 covers a local area of ​​the flexible base layer 230 .

[0072] The middle sacrificial layer 290 may be formed by the following method 1 or method 2.

[0073] Method 1: Form a first patterned mask on the flexible substrate layer 230 by spin coating photoresist, baking, exposure and development. The first patterned mask exposes a portion of the flexible substrate layer 230; an intermediate sacrificial layer 290 is formed on the flexible substrate layer 230 exposed by the first patterned mask; the intermediate sacrificial layer 290 may include one or more of Al, Ti, Ni, and Cr, and the intermediate sacrificial layer 290 may be formed by electron beam evaporation or magnetron sputtering; remove the first patterned mask, and the first patterned mask may be removed by a stripping process.

[0074] Method 2: An intermediate sacrificial layer 290 having a specific pattern is formed on the flexible base layer 230 by an etching process, and the intermediate sacrificial layer 290 covers a partial surface of the flexible base layer 230 .

[0075] S620 : forming an opening 310 penetrating the substrate layer 210 , the bottom sacrificial layer 220 , and the flexible base layer 230 , wherein the opening 310 exposes the middle sacrificial layer 290 .

[0076] The middle opening 310 may be formed by the following steps S621 to S625:

[0077] S621: forming a protective glue on the flexible protective layer 260. The protective glue can protect the flexible protective layer 260 from damage caused by subsequent process steps.

[0078] S622: Flip the neural electrode.

[0079] S623: forming a second patterned mask on the back side of the substrate layer 210. For example, the second patterned mask is formed by spin coating photoresist, baking, exposure and development, and the second patterned mask may be an organic mask.

[0080] S624 : etching the substrate layer exposed by the second patterned mask to form an opening 310 .

[0081] S625: removing the second patterned mask and the protective glue.

[0082] S630: etching and removing the middle sacrificial layer 290 through the opening 310 to form the space 280. The middle sacrificial layer 290 may be removed by a wet etching process.

[0083] In step S150 , the substrate layer 210 and the bottom sacrificial layer 220 are removed. The bottom sacrificial layer 220 may be removed by a wet etching process. After the bottom sacrificial layer 220 is removed, the substrate layer 210 is separated from the film layer above it, thereby achieving the purpose of removing the substrate layer 210 .

[0084] refer to Figure 5 As shown, in one embodiment, the preparation method further includes a step of profile etching, and the profile etching includes the following steps:

[0085] S710: Form a fifth patterned mask on the flexible protective layer 260 by spin coating photoresist, baking, exposure and development. The shape of the outline of the fifth patterned mask is the same as the outline of the neural electrode to be finally prepared.

[0086] S720: Etching the film layer not covered by the fifth patterned mask to form a neural electrode with a preset contour. Figure 5 As shown, one end of the nerve electrode is arc-shaped, which can reduce damage to the tissue. It is understood that the preset contour is not limited to Figure 5 As shown, it can be designed according to requirements.

[0087] S730: removing the fifth patterned mask.

[0088] refer to Figure 4 and Figure 5 As shown, on the other hand, the present application also proposes a sheath-type flexible neural electrode, including: a flexible base layer 230, a flexible intermediate layer 240, an interconnection layer 250 and a flexible protective layer 260 arranged in a stacked manner; an electrode layer 270, the electrode layer 270 passes through the flexible protective layer 260 and contacts the interconnection layer 250, and the two are electrically connected; and a space 280 located in the flexible intermediate layer 240.

[0089] The above-mentioned neural electrode can be prepared by the preparation method as described above.

[0090] The basic concepts have been described above. Obviously, for those skilled in the art, the above application disclosure is only an example and does not constitute a limitation of the present application. Although not explicitly stated herein, those skilled in the art may make various modifications, improvements and amendments to the present application. Such modifications, improvements and amendments are suggested in the present application, so such modifications, improvements and amendments still belong to the spirit and scope of the exemplary embodiments of the present application.

[0091] At the same time, the present application uses specific words to describe the embodiments of the present application. For example, "one embodiment", "an embodiment", and / or "some embodiments" refer to a certain feature, structure or characteristic related to at least one embodiment of the present application. Therefore, it should be emphasized and noted that "one embodiment" or "an embodiment" or "an alternative embodiment" mentioned twice or more in different positions in this specification does not necessarily refer to the same embodiment. In addition, some features, structures or characteristics in one or more embodiments of the present application can be appropriately combined.

[0092] Similarly, it should be noted that in order to simplify the description of the disclosure of this application and thus help understand one or more application embodiments, in the above description of the embodiments of this application, multiple features are sometimes merged into one embodiment, figure or description thereof. However, this disclosure method does not mean that the features required by the object of this application are more than the features mentioned in the claims. In fact, the features of the embodiments are less than all the features of the single embodiment disclosed above.

[0093] In some embodiments, numbers describing the number of components and attributes are used. It should be understood that such numbers used in the description of the embodiments are modified by the modifiers "about", "approximately" or "substantially" in some examples. Unless otherwise specified, "about", "approximately" or "substantially" indicate that the numbers are allowed to vary by ±20%. Accordingly, in some embodiments, the numerical parameters used in the specification and claims are approximate values, which may change according to the required features of individual embodiments. In some embodiments, the numerical parameters should take into account the specified significant digits and adopt the general method of retaining digits. Although the numerical domains and parameters used to confirm the breadth of their range in some embodiments of the present application are approximate values, in specific embodiments, the setting of such numerical values ​​is as accurate as possible within the feasible range.

[0094] Although the present application has been described with reference to the current specific embodiments, ordinary technicians in this technical field should recognize that the above embodiments are only used to illustrate the present application, and various equivalent changes or substitutions may be made without departing from the spirit of the present application. Therefore, as long as the changes and modifications to the above embodiments are within the essential spirit of the present application, they will fall within the scope of the claims of the present application.

Claims

1. A method for preparing a sheath-type flexible neural electrode, characterized in that: include: providing a substrate layer; forming a bottom sacrificial layer, a flexible base layer, an intermediate sacrificial layer, a flexible intermediate layer, an interconnection layer and a flexible protective layer in sequence on the substrate layer; forming an electrode layer, wherein the electrode layer is in contact with the interconnection layer; removing the middle sacrificial layer to form a space in the flexible middle layer; And removing the substrate layer and the bottom sacrificial layer.

2. The preparation method according to claim 1, characterized in that The steps of forming the space include: forming the intermediate sacrificial layer on the flexible base layer, wherein the intermediate sacrificial layer covers a local area of ​​the flexible base layer; forming an opening penetrating the substrate layer, the bottom sacrificial layer and the flexible base layer, the opening exposing the middle sacrificial layer; The middle sacrificial layer is removed by etching through the opening to form the space.

3. The preparation method according to claim 2, characterized in that: The intermediate sacrificial layer is formed by the following method 1 or method 2: Method 1: forming a first patterned mask on the flexible base layer by spin coating photoresist, baking, exposing and developing, forming the intermediate sacrificial layer on the flexible base layer exposed by the first patterned mask, and removing the first patterned mask; Method 2: forming the intermediate sacrificial layer on the flexible base layer through an etching process.

4. The preparation method according to claim 2, characterized in that: The steps of forming the opening include: forming a protective glue on the flexible protective layer; flipping the neural electrode; forming a second patterned mask on the back side of the substrate layer; Etching the substrate layer exposed by the second patterned mask to form the opening; The second patterned mask and the protective glue are removed.

5. The preparation method according to any one of claims 2 to 4, characterized in that: The bottom sacrificial layer and the middle sacrificial layer are removed using a wet etching process.

6. The preparation method according to claim 1, characterized in that: The flexible base layer has a connection hole, and a portion of the flexible middle layer is embedded in the connection hole to increase the bonding force between the flexible base layer and the flexible middle layer.

7. The preparation method according to claim 6, characterized in that: The step of forming the connection hole comprises: forming a sixth patterned mask on the flexible base layer by spin coating, baking, exposure and development; Etching the flexible base layer exposed by the sixth patterned mask to form the connecting hole; The sixth patterned mask is removed.

8. The preparation method according to claim 1, characterized in that: The step of forming the bottom sacrificial layer comprises: forming a third patterned mask on the substrate layer by spin coating photoresist, baking, exposing and developing; forming a bottom sacrificial layer on the substrate layer exposed by the third patterned mask; The third patterned mask is removed.

9. The preparation method according to claim 1, characterized in that: The flexible base layer includes a polymer flexible material, wherein the polymer flexible material includes any one of polyimide, polydimethylsiloxane, silicone rubber, SU-8 photoresist negative resist, and polyparaxylene.

10. The preparation method according to claim 1, characterized in that: The flexible intermediate layer is formed by spin coating, baking curing or physical vapor deposition, and / or the flexible protective layer is formed by spin coating, baking curing or physical vapor deposition, and the flexible protective layer wraps the interconnection layer, wherein the flexible intermediate layer and the flexible protective layer include a polymer flexible material, and the polymer flexible material includes any one of polyimide, polydimethylsiloxane, silicone rubber, SU-8 photoresist negative resin, and polyparaxylene.

11. The preparation method according to claim 1, characterized in that: The steps of forming the interconnect layer include: Forming a fourth patterned mask on the flexible intermediate layer by spin coating photoresist, baking, exposing and developing; forming the interconnection layer on the flexible intermediate layer exposed by the fourth patterned mask; The fourth patterned mask is removed.

12. The preparation method according to claim 1, characterized in that: Also included is profile etching, the profile etching comprising the steps of: Forming a fifth patterned mask on the flexible protective layer by spin coating photoresist, baking, exposing and developing; Etching the film layer not covered by the fifth patterned mask to form a neural electrode with a preset contour; The fifth patterned mask is removed.

13. The preparation method according to claim 1, characterized in that: The step of forming the electrode layer comprises: Forming a sixth patterned mask on the flexible protective layer by spin coating photoresist, baking, exposing and developing; removing the flexible protective layer exposed by the sixth patterned mask to expose the interconnection layer; forming the electrode layer on the exposed interconnection layer; The sixth patterned mask is removed.

14. A sheath-type flexible neural electrode, characterized in that: include: A flexible base layer, a flexible middle layer, an interconnection layer and a flexible protective layer are stacked; an electrode layer, penetrating through the flexible protective layer and contacting the interconnection layer; as well as A space is located in the flexible middle layer.

15. A sheath-type flexible neural electrode, characterized in that: The neural electrode is prepared by the preparation method according to any one of claims 1 to 13.

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