Electrode structure and method of manufacturing an electrode structure

Abstract

The embodiment of the present application provides an electrode structure and a manufacturing method of the electrode structure, wherein the electrode structure comprises: a main body; an electrode contact point arranged on the main body; wherein the electrode contact point is used for contacting brain tissue; a lead wire connected with each electrode contact point; a fixing anchor arranged on the periphery of the main body; wherein the fixing anchor is used for connecting with the periphery structure of the brain tissue; the fixing anchor is connected with the main body through a flexible pivot; and the hardness of the fixing anchor is greater than the hardness of the flexible pivot. Through the electrode structure, the stable connection between the electrode structure and the brain tissue can be improved, and the electrode structure detachment can be reduced.

Description

Technical Field

[0001] This application relates to the field of brain-computer interface technology, and more specifically, to an electrode structure and a method for fabricating the electrode structure. Background Technology

[0002] With the rapid development of brain-computer interface (BCI) technology, implantable and wearable products have been widely used in fields such as neurorehabilitation and motor function reconstruction. Flexible electrodes, due to their excellent biocompatibility and mechanical compliance, have become key signal acquisition and stimulation transmission components in BCI systems.

[0003] In existing technologies, flexible electrodes typically form an interface with nerve tissue using bioadhesive materials. Under static conditions, these implants maintain good interfacial stability. However, during daily activities, various physiological movements inevitably occur in different parts of the body: mechanical disturbances such as whole-body vibrations during walking, head rotation, and changes in body position during sleep continuously act on the implantation site. These dynamic loads can lead to a decrease in the adhesion strength between the electrode and the tissue interface, causing partial contact failure or complete detachment of the electrode. Summary of the Invention

[0004] The purpose of this application is to provide an electrode structure and a method for manufacturing the electrode structure, which can improve the stable connection between the electrode structure and brain tissue and reduce the detachment of the electrode structure.

[0005] In a first aspect, the present invention provides an electrode structure comprising: a main body; electrode contacts disposed on the main body; wherein the electrode contacts are used to contact brain tissue; lead wires connected to each electrode contact; and a fixing anchor disposed around the main body; wherein the fixing anchor is used to connect to the surrounding structure of the brain tissue; the fixing anchor is connected to the main body via a flexible rotating shaft; and the hardness of the fixing anchor is greater than the hardness of the flexible rotating shaft.

[0006] In the above embodiments, the fixed anchor provides mechanical anchoring force, which reduces electrode displacement and enables a more stable connection between the electrode structure and brain tissue. Furthermore, the flexible pivot between the main body and the fixed anchor allows for relative movement between them, enabling the main body to deform with the minute pulsations of the brain tissue and reducing mechanical stress damage. Specifically, because the fixed anchor is more rigid than the flexible pivot, the fixed pivot can provide a more stable gripping force, achieving a stable connection with the surrounding structures of the brain tissue.

[0007] Secondly, the present invention provides a method for fabricating an electrode structure, used to fabricate an electrode structure according to any of the foregoing embodiments. The method includes: forming a flexible material layer on a substrate structure; forming a first anchor material layer on the flexible material layer; wherein the hardness of the first anchor material layer is greater than that of the flexible material layer; sputtering a metal layer comprising electrode contacts, leads, and pads of an electrode structure in a main area defined on the first anchor material layer; removing the anchor material portion of the first anchor material layer corresponding to a pivot region to form a first fixed anchor layer; and exposing the flexible material layer in the pivot region to form a flexible pivot of the electrode structure, the pivot region being located between the main area and the first fixed anchor layer; and applying an anchor material layer at the location of the first fixed anchor layer to form a second fixed anchor layer.

[0008] The above embodiments provide a method for processing electrode structures. Because the fixed anchor, rotating shaft, and main body are formed integrally during processing, there is no need for secondary processing to form structures other than the main body (fixed anchor, rotating shaft, etc.), thus reducing the overall processing difficulty of the electrode structure. Specifically, using patterned etching of flexible and anchor material layers, a heterogeneous structure of rigid (main body), flexible (flexible rotating shaft), and rigid (fixed anchor) is achieved on the same substrate; the design of multiple fixed anchor layers allows for precise control of the fixed anchor thickness, avoiding the internal stress problem of single-stage thick film processing and improving the yield. Attached Figure Description

[0009] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0010] Figure 1 This is a schematic diagram of the electrode structure provided in the embodiments of this application; Figure 2 This is a schematic diagram of the fixed anchor structure of the electrode structure provided in the embodiments of this application; Figure 3a A schematic diagram of the structure of the electrode structure provided in the embodiment of this application, showing the cooperation between the fixed anchor and the flexible rotating shaft; Figure 3b Another schematic diagram of the fixed anchor and flexible rotating shaft of the electrode structure provided in the embodiment of this application; Figure 4 Another schematic diagram of the fixed anchor and flexible rotating shaft of the electrode structure provided in the embodiment of this application; Figure 5 A flowchart illustrating the method for fabricating the electrode structure provided in the embodiments of this application; Figure 6A set of cross-sectional structural schematic diagrams obtained during the fabrication process of the electrode structure provided in the embodiments of this application; Figure 7 Another detailed flowchart of the method for fabricating the electrode structure provided in the embodiments of this application; Figure 8 A further detailed flowchart of the method for fabricating the electrode structure provided in the embodiments of this application; Figure 9 Another set of cross-sectional structural schematic diagrams obtained during the fabrication process of the electrode structure provided in the embodiments of this application; Figure 10 Another detailed flowchart of the method for fabricating the electrode structure provided in the embodiments of this application; Figure 11 This is another set of cross-sectional structural schematic diagrams obtained during the fabrication process of the electrode structure provided in the embodiments of this application.

[0011] Icons: 110 - Main body; 120 - Electrode contact; 130 - Lead; 140 - Fixed anchor; 141 - Raised structure; 150 - Flexible hinge; 160 - Pad; 310 - Substrate structure; 320 - Flexible material layer; 330 - First anchor material layer; 340 - First photoresist pattern layer; 350 - Metal layer; 360 - Hinge area; 370 - First fixed anchor layer; 380 - Second anchor material layer; 390 - Third photoresist pattern layer; 400 - Fifth photoresist pattern layer; 410 - Dicing area; 420 - Aluminum layer; 430 - Sixth photoresist pattern layer; 444 - Third anchor material layer; 450 - Fourth photoresist pattern layer. Detailed Implementation

[0012] The technical solutions in the embodiments of this application will now be described with reference to the accompanying drawings.

[0013] It should be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. Furthermore, in the description of this application, terms such as "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0014] In the description of this application, it should be noted that the terms "upper", "lower", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of the invention is usually placed when in use. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations of this application.

[0015] In the description of this application, it should also be noted that, unless otherwise expressly specified and limited, the terms "set," "install," and "connect" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0016] Currently, after the brain-computer interface electrodes are precisely implanted into the target brain region via surgery, patients need to wear external assistive devices under the supervision of a professional medical institution for system adjustment. Once the adjustment phase is successfully completed, the implantable components and external devices of the brain-computer interface system will work together to help patients adapt to various daily life scenarios. In daily life scenarios, disturbances caused by normal physiological activities such as walking, various head movements, and sleep may cause the implanted flexible electrodes to detach or shift.

[0017] Dislodgement or displacement of implanted brain-computer interface electrodes from brain tissue can lead to a series of adverse clinical and functional consequences. Firstly, it significantly reduces the actual density of the stimulation current received by the brain tissue, making it difficult to achieve the expected neuromodulation or functional rehabilitation effects. Secondly, it may cause amplitude attenuation, decreased signal-to-noise ratio, and waveform distortion in the acquired physiological electrical signals, thereby affecting the accuracy of signal interpretation and the reliability of monitoring results. Such electrode stability issues not only directly weaken the effectiveness of medical interventions but may also induce risks such as treatment interruption, misdiagnosis, and even secondary tissue damage, seriously threatening patient safety and postoperative recovery.

[0018] To improve the stability of the connection between implanted brain-computer interface (BCI) electrodes and brain tissue, existing technologies incorporate elastic structures on the electrodes. These elastic structures provide cushioning, allowing the electrodes room for elastic deformation under external forces, thus reducing damage to the brain tissue. Furthermore, the elastic structures reduce the relative movement between the flexible micro-cortical electrodes and the brain tissue. However, these elastic structures require secondary processing after the BCI electrodes are initially fabricated, resulting in low processing efficiency and not altering the relatively stable connection between the BCI electrodes and the brain tissue.

[0019] Based on the above research, this application provides an electrode structure and a method for fabricating the electrode structure, which can improve the stable connection between the electrode structure and brain tissue and reduce electrode detachment.

[0020] The following describes an electrode structure and a method for fabricating the electrode structure provided in this application, using several embodiments as examples.

[0021] like Figure 1 As shown, Figure 1 This is a schematic diagram of the electrode structure provided in an embodiment of this application. The electrode structure provided in this embodiment includes: a main body 110, an electrode contact 120, a lead wire 130, and a fixing anchor 140.

[0022] The shape of the main body 110 of the electrode structure can be configured as needed. For example, the electrode structure can be rectangular, pentagonal, hexagonal, circular, elliptical, etc. Figure 1 In the example shown, its main body 110 has a pentagonal structure. Although Figure 1 The pentagonal structure shown is a non-regular pentagon. It is understood that the shape of the main body 110 can also be other shapes depending on the actual needs. For example, the shape of the main body 110 can be adapted to other shapes depending on the number of electrode contacts 120 required or the arrangement requirements of the electrode contacts 120.

[0023] Electrode contacts 120 are disposed on the main body 110. Electrode contacts 120 are used to contact brain tissue. Electrode contacts 120 can stimulate brain tissue. Electrode contacts 120 can also be signal monitoring contacts used to detect feedback signals from brain tissue.

[0024] The electrode contacts 120 can be evenly distributed on the main body 110.

[0025] For example, the electrode contacts 120 can be distributed in an array on the body 110. The shape of the array can match the shape of the body 110. For example, if the body 110 is rectangular, the array of electrode contacts 120 can also be rectangular; as another example, if the body 110 is pentagonal, the array of electrode contacts 120 can also be pentagonal. Figure 1 In the example shown, the main body 110 is pentagonal in shape, and the array of its electrode contacts 120 is also pentagonal.

[0026] During use, the electrode contacts 120 can come into contact with brain tissue. The electrode contacts 120 can be used to stimulate the brain tissue. The electrode contacts 120 can also be used to monitor signals from the brain tissue. Exemplarily, among the multiple electrode contacts 120 distributed on the body 110, a portion of the electrode contacts 120 are used to stimulate the brain tissue, while another portion is used to monitor signals from the brain tissue. Exemplarily, the electrode contacts 120 for stimulating the brain tissue and the electrode contacts 120 for monitoring the brain tissue can be arranged alternately. For example, assuming the electrode contacts 120 are arranged in a rectangular matrix array, the odd-numbered columns are for stimulating the brain tissue, and the even-numbered columns are for monitoring the brain tissue. For example, taking the electrode contacts 120 arranged in a rectangular matrix array, each electrode contact 120 that stimulates brain tissue is adjacent to an electrode contact 120 that monitors brain tissue, and each electrode contact 120 that monitors brain tissue is adjacent to an electrode contact 120 that stimulates brain tissue.

[0027] Electrode contact 120 can be connected to lead 130, and the other end of lead 130 can be connected to pad 160.

[0028] The fixing anchors 140 are disposed around the body 110. For example, the electrode structure may include multiple fixing anchors 140, each distributed around the body 110. The fixing anchors 140 are connected to the body 110 via flexible pivots 150.

[0029] During the use of the electrode structure, the fixing anchor 140 is used to connect with the surrounding structures of the brain tissue. The fixing anchor 140 enables a more stable connection between the electrode structure and the brain tissue. The surrounding structures of the brain tissue can be the dura mater or the cerebral cortex. For example, when the electrode structure needs to be implanted into the brain tissue, to achieve stable fixation of the electrode structure, the fixing anchor 140 can be inserted between the dura mater and the arachnoid mater, facing towards the arachnoid mater, thereby achieving relative positioning of the electrode structure.

[0030] The fixed anchor 140 has a higher hardness than the flexible shaft 150. For example, the fixed anchor 140 can be made of a relatively harder material, while the flexible shaft 150 can be made of a relatively softer material.

[0031] In an alternative embodiment, the flexible pivot 150 may be made of a relatively soft material, such as polydimethylsiloxane (PDMS), medical-grade thermoplastic polyurethane (TPU), aliphatic polyurethane, polyethylene glycol (PEG), polyacrylamide (PAAm), etc.

[0032] In an alternative embodiment, the material used for the anchor 140 can be a relatively rigid material. For example, the anchor 140 can be made of polyimide, such as HD PI2611, HD-4110, HD-8820, etc. Alternatively, the anchor 140 can also be made of benzocyclobutene (BCB), parylene, etc.

[0033] The flexible pivot 150 is made of a relatively soft material, which allows the fixing anchor 140 to bend flexibly relative to the main body 110, better adapting to implantation in brain tissue and securing it in the peripheral structures of the brain tissue. Furthermore, given that the flexible pivot 150 is made of a relatively flexible material, the risk of pivot breakage can be effectively reduced when the fixing anchor 140 bends relative to the main body 110 structure, improving the safety of the electrode structure.

[0034] To further improve the stability of the anchor 140 when it is installed on the peripheral structures of the brain tissue, the edge of the anchor 140 includes one or more protrusions 141.

[0035] like Figure 2 As shown, a schematic diagram of the structure of the fixed anchor 140 is shown, with the protruding structures 141 of the fixed anchor 140 distributed on both sides of the fixed anchor 140. Figure 2 In the example shown, three protruding structures 141 are provided on both sides of the fixing anchor 140. Of course, the number of fixing anchors 140 can vary depending on the actual needs. For example, the number of protruding structures 141 can also be adjusted adaptively based on the size of the fixing anchor 140. For instance, the larger the size of the fixing anchor 140, the more protruding structures 141 can be; the smaller the size of the fixing anchor 140, the fewer protruding structures 141 can be.

[0036] exist Figure 2 In the example shown, the edge of the protrusion 141 forms a pointed portion. The extending direction of the protrusion 141 forms a predetermined angle with the edge of the fixed anchor 140, the predetermined angle being 20° to 80°. The angle formed by the extending direction of the protrusion 141 and the edge of the fixed anchor 140 can be represented as the angle formed by one side of the pointed portion and the edge of the fixed anchor 140, such as... Figure 2 The angle α shown is the angle formed by the extension direction of the protruding structure 141 and the edge of the fixed anchor 140. This angle can be represented by the angle bisector of the tip and the edge of the fixed anchor 140, as shown below. Figure 2 The angle β shown.

[0037] The fixed anchor 140 designed above can make the connection between the fixed anchor 140 and the surrounding structures of the brain tissue more stable, thereby improving the stability of the electrode structure installation.

[0038] To reduce the stress on the electrode structure during bending, the connection edge between the flexible rotating shaft 150 and the fixed anchor 140 is an arc-shaped edge, or a curved edge formed by multiple arc-shaped connections.

[0039] like Figure 3a and Figure 3b As shown in the figure, two different implementations of the connection edge between the flexible rotating shaft 150 and the fixed anchor 140 are illustrated. Among them, Figure 3a The example shown has a curved connection between the flexible shaft 150 and the fixed anchor 140, meaning the flexible shaft 150 is crescent-shaped. Figure 3a The example shown is a curved edge formed by multiple arc connections between the flexible rotating shaft 150 and the fixed anchor 140, which is a wave shape. Figure 3a and Figure 3b This is just an illustrative illustration. Depending on actual design requirements and manufacturing process differences, the line shape of the connection between the flexible rotating shaft 150 and the fixed anchor 140 may not be limited to the example shown in the illustration. The key design is that the connection edge should present a curved shape.

[0040] Considering the need for better stable installation of the electrode structure during implantation, the thickness of the flexible shaft 150 can be less than the thickness of the fixed anchor 140, and the thickness of the flexible shaft 150 is also less than the thickness of the main body 110.

[0041] For example, the flexible shaft 150 has a thickness of 10 μm to 50 μm, and the fixed anchor 140 has a thickness of 70 μm to 200 μm. For instance, the flexible shaft 150 may have thicknesses of 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, etc. Similarly, the fixed anchor 140 may have thicknesses of 70 μm, 80 μm, 90 μm, 100 μm, 110 μm, 130 μm, 150 μm, 160 μm, 170 μm, 190 μm, 200 μm, etc.

[0042] In some alternative embodiments, the thickness of the anchor 140 may also be greater than the thickness of the body 110.

[0043] For example, the thickness of the body 110 is 70 μm to 140 μm. The thickness of the body 110 is 70 μm, 80 μm, 90 μm, 100 μm, 120 μm, 140 μm, etc.

[0044] In some alternative implementations, the anchors 140 are distributed at the vertices of the polygonal structure formed by the body 110.

[0045] In some alternative embodiments, the anchors 140 are distributed at specific locations on the sides of the polygonal structure formed by the body 110. These specific locations may be the midpoints of the sides or one-third of the way along each side.

[0046] exist Figure 1 In the example shown, seven fixed anchors 140 are set around the main body 110. The positions of the fixed anchors 140 include the vertices of the polygonal structure formed by the main body 110, as well as specific positions of the edge structures of part of the polygonal structure.

[0047] By distributing the fixing anchors 140 at multiple locations around the main body 110, a more uniform fixing force can be applied to the main body 110, making the installation of the electrode structure more stable.

[0048] In the embodiments provided in this application, in the first state, the fixing anchor 140 and the main body 110 are coplanar. The first state can be the state after the electrode structure is manufactured and before it is implanted into the area of ​​the brain tissue required for implantation.

[0049] In the embodiments provided in this application, in the second state, the electrode structure has the fixed anchor 140 forming an angle with the main body 110, the angle being greater than 0 and less than 180°. In one example, such as... Figure 4 As shown, in the second state, the angle between the fixed anchor 140 and the main body 110 can be 90°.

[0050] The second state is the state during the implantation process or after the brain tissue has reached the required area.

[0051] The structural composition and working principle of the electrode structure have been introduced previously. However, the structural design of the electrode structure requires a reliable manufacturing process to fully realize its expected performance. The following section will use cross-sectional diagrams illustrating the electrode structure formation process to introduce the fabrication method and key technological flows.

[0052] like Figure 5 and Figure 6 As shown, Figure 5 A flowchart illustrating a method for fabricating an electrode structure according to an embodiment of this application is shown. The method for fabricating an electrode structure according to an embodiment of this application may include the following steps.

[0053] Step 210: Form a flexible material layer on the substrate structure.

[0054] The flexible material layer 320 can be polydimethylsiloxane (PDMS). Figure 6 (a) shows the substrate structure 310 and the flexible material layer 320.

[0055] In this embodiment, a PDMS coating can be formed on the substrate structure 310 by spin coating. After the coating is formed, it can be cured at a first curing temperature for a first time to form a flexible material layer 320.

[0056] For example, the first curing temperature can be from 60°C to 100°C, such as 60°C, 70°C, 80°C, 90°C, 95°C, 100°C, etc. For example, using 60°C to cure the flexible material layer 320 allows for slow cross-linking of the flexible material layer, effectively reducing the generation of internal bubbles, reducing the likelihood of wrinkling or cracking of the coating due to rapid evaporation of solvents or low-molecular-weight substances, and improving the stability of the flexible material layer. As another example, using 100°C to cure the flexible material layer 320 allows for more complete cross-linking of the flexible material layer, achieving the required flexibility, elasticity, and chemical stability.

[0057] For example, the first duration can be 1 hour to 2 hours, such as 1 hour, 1.5 hours, 2 hours, etc.

[0058] Before performing the subsequent step 230, the method provided in this application embodiment may further include: step 220, activating the flexible material layer.

[0059] Alternatively, the flexible material layer 320 can be activated by bombarding the surface with oxygen plasma.

[0060] Optionally, the sample formed in step 210 can be immersed in an organosilicon coupling agent at room temperature for a second time, and then dried to achieve surface activation.

[0061] For example, the second duration mentioned above can be from 0.8 hours to 1.5 hours, such as 0.8 hours, 1 hour, 1.5 hours, etc.

[0062] For example, the drying temperature used in the drying process can be between 70°C and 90°C, such as 70°C, 80°C, or 90°C. A drying process at a temperature of 70°C to 90°C effectively evaporates residual solvents in the soaking solution and water generated during the condensation reaction. 90°C is significantly lower than the thermal degradation / aging temperature of PDMS, preventing deformation or embrittlement of the flexible material layer; it is also lower than the decomposition temperature of the silicone coupling agent, preventing its failure.

[0063] The activation treatment described above can improve the bonding force between the flexible material layer 320 and the structure subsequently formed on the flexible material layer 320.

[0064] Step 230: Form a first anchor material layer on the flexible material layer.

[0065] in, Figure 6 (b) shows the first anchor material layer 330.

[0066] The first anchor material layer 330 has a higher hardness than the flexible material layer 320. The first anchor material layer 330 may be a polyimide layer.

[0067] Optionally, the first anchor material layer 330 can be formed by multi-layer spin coating. After spin coating the first anchor material layer 330, it can be cured at a second curing temperature to form a stable first anchor material layer 330. Forming the first anchor material layer by multi-layer spin coating can reduce excessive adhesive buildup at the edges during spin coating and reduce the likelihood of surface streaks or uneven thickness.

[0068] For example, the second curing temperature can be a specific temperature from 200°C to 350°C, such as 200°C, 230°C, 250°C, 280°C, 290°C, 300°C, 310°C, 320°C, 330°C, 340°C, or 350°C. Since the dehydration cyclization reaction of polyimide begins at around 150°C, and the reaction rate only significantly accelerates above 200°C, temperatures between 200°C and 350°C allow for a relatively higher conversion rate of polyimide, resulting in a stable network structure.

[0069] For example, the second curing temperature can be a stepped temperature that gradually increases as curing progresses. For instance, the range of the second curing temperature can be from 200°C to 350°C. For example, in the initial curing stage, the curing temperature can be 200°C, and as curing proceeds, the curing temperature gradually increases to a temperature not exceeding 350°C. This gradual increase in the second curing temperature allows residual solvents and water molecules generated by the cyclization reaction to evaporate slowly in the early stages of curing, preventing the formation of bubbles, pinholes, or delamination inside the film due to rapid gas expansion, thus ensuring the density of the 30μm thick film. Using a higher temperature in the later stages of curing can achieve near 100% formation of the final polyimide structure.

[0070] In this embodiment, the thickness of the first anchor material layer 330 can be from 30 μm to 45 μm. For example, the thickness of the first anchor material layer 330 can be 30 μm, 33 μm, 35 μm, 38 μm, 40 μm, 45 μm, etc. The thickness of the first anchor material layer 330 can be from 30 μm to 45 μm, which allows it to maintain the rigidity of the anchor without being too thick.

[0071] Step 250: In the main area defined on the first anchor material layer, a metal layer containing electrode contacts, leads and pads of the electrode structure is sputtered.

[0072] in, Figure 6(d) in the figure shows metal layer 350.

[0073] The main area can be the area where electrode contacts 120, leads 130, and pads 160 need to be formed.

[0074] In some alternative implementations, such as Figure 7 As shown, step 250 may include steps 251 and 252.

[0075] Step 251: Form a first photoresist pattern layer on the first anchor material layer.

[0076] The windowed area in the first photoresist pattern layer 340 is the main area of ​​the electrode structure. This can be understood as including the electrode contact area, lead area, and pad area of ​​the electrode structure.

[0077] in, Figure 6 (c) in the figure shows the first photoresist pattern layer 340.

[0078] Optionally, the first photoresist pattern layer 340 can be formed by spin-coating, exposure, and development of photoresist. For example, the photoresist can be a positive stripping photoresist, and the positive stripping photoresist can be AR-P5350.

[0079] Optionally, the thickness of the first photoresist pattern layer 340 can be from 0.8 μm to 1.5 μm. For example, the thickness of the first photoresist pattern layer 340 can be 0.8 μm, 0.9 μm, 1 μm, 1.2 μm, 1.3 μm, 1.5 μm, etc.

[0080] Step 252: A metal layer containing electrode contacts, leads, and pads of an electrode structure is sputtered in the windowed area of ​​the first photoresist pattern layer.

[0081] Optionally, an adhesion layer is first formed by sputtering using a magnetron sputtering device, followed by a conductive layer, and then a metal layer 350 for the electrode contacts 120, leads 130, and pads 160 is ultrasonically formed in acetone.

[0082] For example, the material of the adhesion layer can be titanium (Ti), and the material of the conductive layer can be gold (Au).

[0083] The thickness of the adhesion layer can range from 80 nm to 130 nm. For example, the thickness of the adhesion layer can be 80 nm, 90 nm, 100 nm, 120 nm, 130 nm, etc.

[0084] The thickness of the conductive layer can range from 180 nm to 230 nm. For example, the thickness of the conductive layer can be 180 nm, 190 nm, 200 nm, 210 nm, 220 nm, 230 nm, etc.

[0085] Step 270: Remove the anchor material portion corresponding to the pivot region in the first anchor material layer to form a first fixed anchor layer; and expose a flexible material layer in the pivot region to form a flexible pivot of the electrode structure.

[0086] The pivot area 360 is located between the main body area and the first fixed anchor layer 370. Among them, Figure 6 (e) shows the pivot region 360 and the first fixed anchor layer 370.

[0087] In some alternative implementations, such as Figure 7 As shown, step 270 may include steps 271 to 273.

[0088] Step 271: After forming the metal layer, a second photoresist pattern layer is formed.

[0089] The second photoresist pattern layer has a 360° windowed area in the pivot region of the electrode structure.

[0090] Optionally, a second photoresist pattern layer is formed by spin-coating, exposure, and development. The window area of ​​the second photoresist pattern layer is the rotation axis region 360 of the electrode structure.

[0091] The photoresist can be a thick positive photoresist, such as AZ-40XT, AZ-4620, AZ-4562, and AZ-125nXT. The thickness of the second photoresist pattern layer can be from 50 μm to 70 μm. For example, the thickness of the second photoresist pattern layer can be 50 μm, 55 μm, 60 μm, 65 μm, or 70 μm.

[0092] Step 272: Remove the anchor material in the windowed area of ​​the second photoresist pattern layer in the first anchor material layer to form a first fixed anchor layer; and expose the flexible material layer in the pivot area to form a flexible pivot of the electrode structure.

[0093] Optionally, the anchor material in the first anchor material layer 330 in the windowed area can be removed by etching, leaving only a portion of the flexible material layer 320 in the windowed area, and a flexible pivot 150 can be formed in the pivot area 360.

[0094] For example, oxygen reactive ion etching technology can be used to remove the anchor material in the first anchor material layer 330 in the windowed area.

[0095] Step 273: Remove the second photoresist pattern layer.

[0096] Alternatively, the second photoresist pattern layer can be removed by soaking and rinsing in acetone.

[0097] Step 290: Apply anchoring material at the location of the first fixed anchor layer to form the second fixed anchor layer.

[0098] In some alternative implementations, such as Figure 7 As shown, step 290 may include steps 291 to 294.

[0099] Step 291: After forming the metal layer, a second anchor material layer is formed on top.

[0100] in, Figure 6 The second anchor material layer 380 is shown in (f).

[0101] The material of the second anchor material layer 380 can be the same as that of the first anchor material layer 330. The formation method of the second anchor material layer 380 can also be the same as that of the first anchor material layer 330. For details, please refer to the description in step 230 above, which will not be repeated here.

[0102] Step 292: Form a third photoresist pattern layer on the second anchor material layer.

[0103] The windowed areas of the third photoresist pattern layer 390 are the electrode contact area, the pad area, and the pivot area 360 of the electrode structure. Figure 6 (g) in the figure shows the third photoresist pattern layer 390.

[0104] The thickness of the third photoresist pattern layer 390 is 55 μm to 70 μm. For example, the thickness of the third photoresist pattern layer 390 is 55 μm, 60 μm, 63 μm, 65 μm, 70 μm, etc.

[0105] Step 293: Etch the windowed area of ​​the third photoresist pattern layer to expose the electrode contacts, pads, and flexible hinge of the electrode structure.

[0106] The area covered by the third photoresist pattern layer 390 forms the second fixing anchor layer 140.

[0107] in, Figure 6 (h) shows a schematic diagram of the state of the electrode contacts 120, pads 160, and flexible shaft 150 that expose the electrode structure.

[0108] For example, oxygen reactive ion etching can be used to remove the anchor material of the second anchor material layer 380 in the windowed area to expose the electrode contact 120, the pad 160, and the flexible hinge 150. Since the anchor material of the second anchor material layer 380 has been removed, the hinge region 360 can expose the flexible material layer 320, thereby preserving the flexibility of the hinge region 360.

[0109] Step 294: Remove the third photoresist pattern layer.

[0110] Optionally, the third photoresist pattern layer 390 can be removed by soaking and rinsing in acetone.

[0111] In some alternative embodiments, the basic structure of the electrode structure can be formed through steps 210 to 290 described above. Based on this, such as Figure 7 As shown, after step 294, the method may further include: step 295, forming a fifth photoresist pattern layer 400 on the current device.

[0112] The fifth photoresist pattern layer 400 exposes the scribe area 410. Among them, Figure 6 (i) shows the fifth photoresist pattern layer 400 and the diced region 410.

[0113] Optionally, photoresist patterning is employed, and the pattern is spin-coated and baked to form a fifth photoresist pattern layer 400.

[0114] The photoresist can also be a thick positive photoresist, such as AZ-40XT, AZ-4620, AZ-4562, and AZ-125nXT. The thickness of the fifth photoresist pattern layer 400 can be from 25μm to 35μm. For example, the thickness of the fifth photoresist pattern layer 400 can be 25μm, 28μm, 30μm, 32μm, or 35μm.

[0115] Step 296: Etch away the flexible material in the flexible material layer in the diced area.

[0116] Alternatively, CF4 and O2 reactive ion etching can be used to remove the flexible material in the flexible material layer 320 of the diced region 410.

[0117] in, Figure 6 (j) shows a schematic diagram of the device after the flexible material in the flexible material layer 320 of the diced region 410 has been etched away.

[0118] Step 297: Place the device obtained in the previous step in a deionized aqueous solution to obtain the electrode structure.

[0119] in, Figure 6 (k) in the figure shows the device (i.e., the electrode structure) after the separation of the substrate structure 310.

[0120] Alternatively, after the currently prepared device has been placed in the deionized aqueous solution for a third time, tweezers can be used to grasp the edge region of the electrode structure containing only anchor material to obtain the motor structure from the deionized aqueous solution.

[0121] The third duration can be between 0.5 hours and 0.8 hours. For example, the third duration can be 0.5 hours, 0.6 hours, 0.7 hours, 0.8 hours, etc.

[0122] Through the above steps 210 to 297, a fixed anchor 140 with two layers of anchor material and a flexible rotating shaft 150 with only a flexible material layer 320 can be obtained. In this embodiment, the anchor material layer is both the structural material of the fixed anchor and the structural material of the electrode body during the manufacturing process.

[0123] To facilitate the removal of the fabricated electrode structure from the substrate structure 310, such as Figure 8 and Figure 9 As shown, before step 210, the method for fabricating the electrode structure provided in this application embodiment may further include: step 201, forming an aluminum layer on the substrate structure.

[0124] Optionally, the thickness of the aluminum layer 420 can be from 0.8 μm to 1.3 μm. For example, the thickness of the aluminum layer 420 can be 0.8 μm, 0.9 μm, 1 μm, 1.2 μm, 1.3 μm, etc. Setting the thickness of the aluminum layer 420 to 0.8 μm to 1.3 μm can achieve isolation between the substrate structure and the electrode structure without being too thick. This reduces the risk of excessive etching time due to excessive thickness, which in turn increases the risk of chemical erosion of the upper flexible electrode or other retained structures on the silicon wafer by the etching solution.

[0125] in, Figure 9 (a) shows that an aluminum layer 420 is formed on the substrate structure 310.

[0126] Step 210 above may include: step 210', forming a flexible material layer on the aluminum layer.

[0127] in, Figure 9 (b) shows the flexible material layer 320 formed on the aluminum layer 420.

[0128] After step 290, step 2150 is also included, in which the currently fabricated device is placed in an aluminum etching solution to obtain an electrode structure.

[0129] To further improve the rigidity of the fixed anchor 140, a third layer of fixed anchor 140 can be stacked on top of the previous two layers. Based on this, as... Figure 10 and Figure 11 As shown, after step 290 and before step 2150, the method for fabricating the electrode structure provided in this application embodiment may further include steps 2100 to 2130.

[0130] Step 2100: Form a third anchor material layer on the current structure.

[0131] The material of the third anchor material layer 440 can be the same as that of the first anchor material layer 330. The formation method of the third anchor material layer can also be the same as that of the first anchor material layer 330, as described in step 230 above, and will not be repeated here.

[0132] in, Figure 11 (l) in the diagram shows the third anchor material layer.

[0133] The third anchor material layer 440 differs from the first anchor material layer 330 in that its thickness can be greater than that of the first anchor material layer 330. The thickness of the third anchor material layer 440 can be between 50 μm and 70 μm. For example, the thickness of the first anchor material layer 330 can be 50 μm, 55 μm, 60 μm, 65 μm, 68 μm, 70 μm, etc.

[0134] Step 2110: Form a fourth photoresist pattern layer on the third anchor material layer.

[0135] The windowed area of ​​the fourth photoresist pattern layer 450 is the area in the electrode structure excluding the fixed anchor area. The fourth photoresist pattern layer 450 can mask the fixed anchor 140 area of ​​the electrode structure. Figure 11 (m) in the figure shows the third anchor material layer 440.

[0136] The thickness of the fourth photoresist pattern layer 450 is 80 μm to 100 μm. For example, the thickness of the fourth photoresist pattern layer 450 is 80 μm, 85 μm, 90 μm, 95 μm, 100 μm, etc.

[0137] Step 2120: Etch the windowed area of ​​the fourth photoresist pattern layer to expose the electrode contacts, pads, and flexible hinge of the electrode structure.

[0138] The area covered by the fourth photoresist pattern layer 450 forms the third fixing anchor layer 140.

[0139] For example, oxygen reactive ion etching can be used to remove the anchor material of the third anchor material layer 440 in the windowed region of the fourth photoresist pattern layer 450 to expose the electrode contacts 120, pads 160, and flexible hinge 150. Since the anchor material of the third anchor material layer 440 has been removed, the hinge region 360 can expose the flexible material layer 320, thereby preserving the flexibility of the hinge region 360.

[0140] Step 2130: Remove the fourth photoresist pattern layer.

[0141] In some alternative embodiments, the basic structure of the electrode structure can be formed through steps 210 to 2130 described above. Based on this, such as Figure 10As shown, before step 2110, the method for fabricating the electrode structure provided in this application embodiment may further include: step 2141, forming a sixth photoresist pattern layer on the current device.

[0142] The sixth photoresist pattern layer 430 exposes the scribe area 410. Among them, Figure 11 (j) shows the sixth photoresist pattern layer 430 and the exposed diced region 410.

[0143] Optionally, photoresist patterning is used, and the patterned layer is spin-coated and baked to form a sixth photoresist pattern layer 430.

[0144] The photoresist can also be a thick positive photoresist, such as AZ-40XT, AZ-4620, AZ-4562, and AZ-125nXT. The thickness of the sixth photoresist pattern layer 430 can be from 25μm to 35μm. For example, the thickness of the sixth photoresist pattern layer 430 can be 25μm, 28μm, 30μm, 32μm, or 35μm.

[0145] Step 2142: Etch away the flexible material in the flexible material layer in the diced area.

[0146] The implementation of step 2142 can be similar to that of step 296 mentioned above. For details, please refer to the description in step 296 mentioned above. It will not be repeated here.

[0147] Optionally, steps 2141 to 2142 can be performed before step 2110 or after step 2130. Figure 10 The flowchart shown is illustrated using the example of execution prior to step 2110.

[0148] In the above implementation, both the fixed anchor 140 and the substrate are made of relatively stiff polyimide material, which ensures that the barbs have sufficient rigidity to insert into the brain tissue. The flexible shaft 150 uses polydimethylsiloxane, which has good flexibility, effectively reducing the significant impact of bending of the fixed anchor 140 on the flexible electrode structure. The flexible shaft 150 uses soft materials and a crescent-shaped or wave-shaped structure, which can further reduce the impact of bending on the electrode structure. The electrode structure is manufactured using an integrated machining method, forming both the flexible electrode structure and the fixed anchor 140 in one piece, resulting in high processing efficiency.

[0149] The above description is merely an optional embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application. It should be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0150] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. An electrode structure, characterized in that, include: main body; Electrode contacts are disposed on the main body; wherein the electrode contacts are used to contact brain tissue; Leads connecting to each electrode contact; Fixed anchors are disposed around the periphery of the main body; wherein, the fixed anchors are used to connect with the peripheral structures of the brain tissue; the fixed anchors are connected to the main body via flexible rotating shafts; the rigidity of the fixed anchors is greater than the rigidity of the flexible rotating shafts.

2. The electrode structure according to claim 1, characterized in that, The edge of the fixed anchor includes one or more protruding structures.

3. The electrode structure according to claim 2, characterized in that, The edge of the protruding structure forms a pointed portion; the extending direction of the protruding structure forms a preset angle with the edge of the fixed anchor, the preset angle being 20° to 80°.

4. The electrode structure according to claim 1, characterized in that, The connection between the flexible rotating shaft and the fixed anchor is an arc-shaped edge, or a curved edge formed by connecting multiple arc segments.

5. The electrode structure according to claim 4, characterized in that, The thickness of the flexible rotating shaft is less than the thickness of the fixed anchor, and the thickness of the flexible rotating shaft is less than the thickness of the main body.

6. The electrode structure according to claim 5, characterized in that, The thickness of the flexible rotating shaft is 10 μm to 50 μm, and the thickness of the fixed anchor is 70 μm to 200 μm.

7. The electrode structure according to claim 5, characterized in that, The thickness of the fixed anchor is greater than the thickness of the main body; the thickness of the fixed anchor is 70 μm to 200 μm, and the thickness of the main body is 70 μm to 140 μm.

8. The electrode structure according to claim 1, characterized in that, The main body is a polygonal structure, and the fixed anchors are distributed at the vertices of the polygonal structure, and / or the fixed anchors are distributed at specific locations on the edges of the polygonal structure.

9. The electrode structure according to any one of claims 1-8, characterized in that, In the first state, the fixed anchor of the electrode structure is coplanar with the main body. In the second state, the electrode structure has the fixed anchor forming an angle with the main body, the angle being greater than 0 and less than 180°. The first state is the state before implantation, and the second state is the state during or after implantation.

10. A method for fabricating an electrode structure, characterized in that, The method for fabricating the electrode structure according to any one of claims 1-9 includes: A flexible material layer is formed on the substrate structure; A first anchor material layer is formed on the flexible material layer; wherein the hardness of the first anchor material layer is greater than that of the flexible material layer; In the main area defined on the first anchor material layer, a metal layer containing the electrode contacts, leads and pads of the electrode structure is sputtered to form; The anchor material portion corresponding to the pivot region in the first anchor material layer is removed to form a first fixed anchor layer, and a flexible material layer is exposed in the pivot region to form a flexible pivot of the electrode structure, the pivot region being located between the main body region and the first fixed anchor layer; An anchoring material is applied at the location of the first fixed anchor layer to form the second fixed anchor layer.

11. The method according to claim 10, characterized in that, Before forming the first anchor material layer on the flexible material layer, the method further includes: The flexible material layer is activated.

12. The method according to claim 10, characterized in that, The step of removing the anchor material portion corresponding to the pivot region from the first anchor material layer to form a first fixed anchor layer, and exposing a flexible material layer in the pivot region to form a flexible pivot of the electrode structure, includes: After the metal layer is formed, a second photoresist pattern layer is formed, the second photoresist pattern layer having a window region in the pivot region of the electrode structure; Remove the anchor material in the first anchor material layer located in the windowed area of ​​the second photoresist pattern layer to form a first fixed anchor layer, and expose a flexible material layer in the pivot area to form a flexible pivot of the electrode structure; Remove the second photoresist pattern layer.

13. The method according to claim 10, characterized in that, The step of applying an anchoring material layer at the location of the first fixed anchor layer to form a second fixed anchor layer includes: After the metal layer is formed, a second anchor material layer is formed; A third photoresist pattern layer is formed on the second anchor material layer; the window area of ​​the third photoresist pattern layer is the electrode contact area, the pad area and the pivot area of ​​the electrode structure. The windowed area of ​​the third photoresist pattern layer is etched to expose the electrode contacts, the pads, and the flexible hinge of the electrode structure; wherein, the area on the first anchor layer covered by the third photoresist pattern layer forms a second anchor layer. Remove the third photoresist pattern layer.

14. The method according to any one of claims 10-13, characterized in that, After forming the second fixed anchor layer, the method further includes: A third anchor material layer is formed on the current structure; A fourth photoresist pattern layer is formed on the third anchor material layer; the window area of ​​the fourth photoresist pattern layer is the area in the electrode structure other than the fixed anchor area. The windowed area of ​​the fourth photoresist pattern layer is etched to expose the electrode contacts of the electrode structure, the pads, and the flexible hinge; wherein the area covered by the fourth photoresist pattern layer forms a third anchor layer. Remove the fourth photoresist pattern layer.

15. The method according to any one of claims 10-13, characterized in that, Before forming a flexible material layer on the substrate structure, the method further includes: An aluminum layer is formed on the substrate structure; The process of forming a flexible material layer on a substrate structure includes: forming a flexible material layer on the aluminum layer; The method further includes placing the currently fabricated device in an aluminum etching solution to obtain an electrode structure.

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