Medical in-vivo implanted ECoG electrode

Abstract

The utility model discloses a medical in-vivo implanted ECoG electrode, and relates to the technical field of brain-computer interfaces. The embodiment of the utility model provides a medical in-vivo implanted ECoG electrode. The medical in-vivo implanted ECoG electrode comprises a flexible substrate, an electrode layer and a packaging layer. The electrode layer is arranged on one side of the flexible substrate, the electrode layer comprises a plurality of electrode contacts, a plurality of electrode welding spots and a plurality of conductive wires, the electrode contacts and the electrode welding spots are arranged in a one-to-one correspondence mode, and each conductive wire is electrically connected with the corresponding electrode contact and the corresponding electrode welding spot. The packaging layer is provided with a contact opening, the electrode contact is exposed in the contact opening, and the minimum distance between the orthographic projection of the contact opening on the plane where the electrode contact is located and the contour line of the electrode contact is larger than or equal to 3 micrometers.

Description

Technical Field

[0001] This application relates to the field of brain-computer interface technology, and more particularly to a medical implantable ECoG electrode. Background Technology

[0002] Brain-computer interfaces (BCIs) are an important technology that connects the brain directly to a computer or other external devices via sensing terminals. This allows for the extraction and decoding of brain signals, ultimately converting them into command signals that can be used to control the external devices. A key function of BCIs is information extraction—the process of reading information from the brain.

[0003] Currently, there are generally two methods for information extraction: non-implantable and implantable. Non-implantable methods involve reading EEG (electroencephalogram) data using an EEG cap worn on the scalp; while implantable methods include obtaining EEG data through implantable microelectrode arrays, deep brain electrodes, or semi-implantable ECoG (electrocorticography) electrodes. Among these technologies, implantable ECoG electrodes are widely used in the field of brain-computer interfaces due to their high signal resolution, relatively long-term stability, and relatively less invasiveness.

[0004] Implantable ECoG electrodes are typically implanted in the subdural cortex to collect information from the brain. However, implantable ECoG electrodes suffer from poor durability. Utility Model Content

[0005] In view of this, this application provides a medical implantable ECoG electrode, which aims to improve the problem of poor durability of existing medical implantable ECoG electrodes.

[0006] In a first aspect, embodiments of this application provide a medical implantable ECoG electrode, the medical implantable ECoG electrode comprising a flexible substrate, an electrode layer, and an encapsulation layer;

[0007] The electrode layer is disposed on one side of the flexible substrate. The electrode layer includes a plurality of electrode contacts, a plurality of electrode solder joints, and a plurality of conductive lines. The plurality of electrode contacts and the plurality of electrode solder joints are arranged in a one-to-one correspondence. Each conductive line is electrically connected to the electrode contact and the corresponding electrode solder joint.

[0008] The encapsulation layer covers the flexible substrate and the electrode layer; the encapsulation layer has a contact opening, the electrode contact is exposed in the contact opening, and the orthographic projection of the contact opening on the plane where the electrode contact is located is located within the outer contour of the electrode contact; the minimum distance between the contour line of the orthographic projection of the contact opening on the plane where the electrode contact is located and the contour line of the electrode contact within it is d, where d is greater than or equal to 3 micrometers.

[0009] In some embodiments of this application, d is greater than or equal to 3 micrometers and less than or equal to 100 micrometers.

[0010] In some embodiments of this application, the electrode layer includes a first metal layer and a second metal layer stacked together.

[0011] In some embodiments of this application, the flexible substrate is a polyimide layer, the first metal layer includes a first titanium layer and a first sub-metal layer; the second metal layer includes a second titanium layer and a second sub-metal layer, and neither the first sub-metal layer nor the second sub-metal layer is a titanium metal layer;

[0012] The polyimide layer, the first titanium layer, the first sub-metal layer, the second titanium layer, and one side of the second sub-metal layer are stacked.

[0013] In some embodiments of this application, the first sub-metal layer includes a first platinum layer, the second sub-metal layer includes a second platinum layer and a gold layer, and the polyimide layer, the first titanium layer, the first platinum layer, the second titanium layer, the second platinum layer and the gold layer are stacked sequentially.

[0014] In some embodiments of this application, the first sub-metal layer includes a first platinum layer, the second sub-metal layer includes a gold layer, and the polyimide layer, the first titanium layer, the first platinum layer, the second titanium layer, and the gold layer are stacked sequentially.

[0015] In some embodiments of this application, the first metal layer and the second metal layer are independently selected from cobalt alloy layer, gold layer, platinum layer, titanium and its compound layer, tungsten layer, iridium and its compound layer, and ruthenium and its compound layer.

[0016] In some embodiments of this application, the electrode contacts include at least one of platinum contacts, cobalt alloy contacts, gold contacts, titanium contacts, titanium nitride contacts, tungsten contacts, iridium contacts, iridium oxide contacts, ruthenium and its compounds contacts, carbon nanotube contacts, and poly(3,4-ethylenedioxythiophene) contacts; and / or

[0017] The electrode solder joints include at least one of the following: gold solder joints, platinum solder joints, aluminum solder joints, tungsten solder joints, titanium solder joints, nickel solder joints, tin solder joints, and copper solder joints.

[0018] In some embodiments of this application, the plurality of electrode contacts include large contacts and small contacts; and / or

[0019] The electrode contacts are circular, and the diameter of the electrode contacts is from 5 μm to 2500 μm; and / or

[0020] The electrode layer includes multiple electrode contacts, which are arranged in an array; and / or

[0021] The electrode layer includes multiple electrode solder joints, which are arranged in an array.

[0022] In some embodiments of this application, the large contact point is circular.

[0023] The diameter of the large contact is 500µm to 2500µm; and / or

[0024] The small contact is circular, and the diameter of the small contact is from 5um to 500um.

[0025] Beneficial effects:

[0026] This application provides a medical implantable ECoG electrode, comprising a flexible substrate, an electrode layer, and an encapsulation layer. The electrode layer is disposed on one side of the flexible substrate and includes a plurality of electrode contacts, a plurality of electrode solder joints, and a plurality of conductive wires. Each electrode contact and electrode solder joint is correspondingly arranged, and each conductive wire electrically connects the electrode contact to the corresponding electrode solder joint. The encapsulation layer covers the area of ​​the flexible substrate and the electrode layer excluding the electrode contacts and electrode solder joints. The encapsulation layer has a contact opening, with the electrode contact exposed within the contact opening. The orthographic projection of the contact opening onto the plane containing the electrode contact lies within the outer contour of the electrode contact. By placing the orthographic projection of the contact opening onto the plane containing the electrode contact within the outer contour of the electrode contact, this application reduces the exposed area of ​​the contact edge, prevents erosion of the contact by the intracranial environment (cerebrospinal fluid), and further extends the electrode's lifespan. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is a front view of one embodiment of the medical implantable ECoG electrode provided in this application;

[0029] Figure 2 yes Figure 1 A magnified view of a section at point A in the middle;

[0030] Figure 3 yes Figure 1 A magnified view of a section at point B in the middle;

[0031] Figure 4 This is a front view of another embodiment of the medical implantable ECoG electrode provided in this application;

[0032] Figure 5 yes Figure 4 A magnified view of a section at point C;

[0033] Figure 6 This is a cross-sectional view of a certain part of the medical implantable ECoG electrode provided in this application;

[0034] Figure 7 yes Figure 6 A magnified view of a section at point D;

[0035] Figure 8 This is a cross-sectional view of a portion of another embodiment of the medical implantable ECoG electrode provided in this application;

[0036] Figure 9 This is a cross-sectional view of a portion of another embodiment of the medical implantable ECoG electrode provided in this application;

[0037] Figure 10 This is a microscopic image of the electrode contacts of the medical implantable ECoG electrode in Comparative Example 1 after an aging experiment.

[0038] Figure 11 This is a microscopic image of the electrode contacts of the medical implantable ECoG electrode in Example 1 after an aging experiment.

[0039] Figure 12 This is a microscope image of the conductive wires of an embodiment of the medical implantable ECoG electrode provided in this application;

[0040] Figure 13 This is a microscope image of the conductive wires of another embodiment of the medical implantable ECoG electrode provided in this application.

[0041] Figure label:

[0042] 100. Medical implantable ECoG electrode; 1. Contact area; 11. Electrode contact; 111. Small contact; 112. Large contact; 12. Hollowed-out part; 2. Solder joint area; 21. Electrode solder joint; 3. Conductive wire; 4. Flexible substrate; 5. Electrode layer; 51. First metal layer; 52. Second metal layer; 6. Encapsulation layer; 61. Contact opening; 7. Adhesive layer. Detailed Implementation

[0043] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application. Furthermore, it should be understood that the specific embodiments described herein are only for illustration and explanation of this application and are not intended to limit this application.

[0044] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the specification of this invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0045] In this application, unless otherwise stated, directional terms such as "upper" and "lower" generally refer to the upper and lower positions of the device in its actual use or operating state, specifically the drawing directions in the accompanying drawings; while "inner" and "outer" refer to the outline of the device. Furthermore, in the description of this application, the term "comprising" means "including but not limited to". The terms first, second, third, etc., are used merely as illustrative purposes and do not impose numerical requirements or establish a numerical order.

[0046] In this application, "and / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. A and B can be singular or plural.

[0047] In this application, "at least one" means one or more, and "more than one" means two or more. "One or more", "at least one of the following", or similar expressions refer to any combination of these items, including any combination of single or multiple items. For example, "at least one of a, b, or c", or "at least one of a, b, and c", can both mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be single or multiple.

[0048] Various embodiments of this application may exist in the form of a range; it should be understood that the description in the form of a range is merely for convenience and brevity and should not be construed as a hard limitation on the scope of this application; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single numerical values ​​within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single numbers within the range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. Furthermore, whenever a numerical range is referred to herein, it means including any referenced number (fraction or integer) within the referred range.

[0049] Brain-computer interfaces (BCIs) are an important technology that connects the brain directly to a computer or other external devices via sensing terminals. This allows for the extraction and decoding of brain signals, ultimately converting them into command signals that can be used to control the external devices. A key function of BCIs is information extraction—the process of reading information from the brain.

[0050] Currently, there are generally two methods for information extraction: non-implantable and implantable. Non-implantable methods involve reading EEG (electroencephalogram) data using an EEG cap worn on the scalp; while implantable methods include obtaining EEG data through implantable microelectrode arrays, deep brain electrodes, or semi-implantable ECoG (electrocorticography) electrodes. Among these technologies, implantable ECoG electrodes are widely used in the field of brain-computer interfaces due to their high signal resolution, relatively long-term stability, and relatively less invasiveness.

[0051] Implantable ECoG electrodes are typically implanted in the subdural cortex to collect information from the brain. However, implantable ECoG electrodes suffer from poor durability.

[0052] In view of this, this application provides a medical implantable ECoG electrode, and the medical implantable ECoG electrode of this application will be further described below with reference to the accompanying drawings.

[0053] Please see Figures 1 to 7 The medical implantable ECoG electrode 100 provided in this application embodiment includes a flexible substrate 4, an electrode layer 5, and an encapsulation layer 6 stacked together. The flexible substrate 4 supports the electrode layer 5 and the encapsulation layer 6.

[0054] For example, a flexible substrate 4 can be prepared by coating a flexible material onto a substrate (e.g., a silicon wafer substrate or a glass substrate, not shown in the figure). The coating method includes spin coating, spray coating, blade coating, etc., and is not limited thereto.

[0055] For example, the materials used to prepare the flexible substrate 4 include at least one of polyimide, SU8, liquid crystal polymer and Parylene C.

[0056] Furthermore, the flexible substrate 4 is a polyimide layer, that is, the material used to prepare the flexible substrate 4 is polyimide. It is understood that, due to the good biocompatibility of polyimide, and the simple molding process and good economy, it is beneficial to improve the biocompatibility of the medical implantable ECoG electrode 100 in this application, and also beneficial to reduce the preparation cost of the flexible substrate 4.

[0057] In some embodiments of this application, the thickness of the flexible substrate 4 can be from 0.1 μm to 1000 μm, that is, from 0.1 micrometers to 1000 micrometers. For example, the thickness of the flexible substrate 4 is 0.1 μm, 1 μm, 2 μm, 4 μm, 6 μm, 9 μm, 15 μm, 20 μm, 50 μm, 100 μm, 200 μm, 300 μm, 400 μm, 500 μm, 600 μm, 700 μm, 800 μm, 900 μm, 1000 μm, and any value between the above values.

[0058] In some embodiments of this application, the thickness of the flexible substrate 4 can be from 1µm to 1000µm.

[0059] In some embodiments of this application, the electrode layer 5 is disposed on the side of the flexible substrate 4 facing away from the substrate. The electrode layer 5 includes a plurality of electrode contacts 11, a plurality of electrode solder joints 21, and a plurality of conductive lines 3.

[0060] Specifically, the electrode layer 5 includes an electrode contact region 1 and an electrode solder joint region 2. The electrode contact region 1 is disposed at the first end of the flexible substrate 4 (e.g., Figure 1 The electrode contact region 1 includes a plurality of electrode contacts 11. The pad region is located on the flexible substrate 4 at a second end away from the first end (e.g., near the top end). Figure 1The pad area (near the bottom end) includes multiple solder joints. Multiple electrode contacts 11 and multiple electrode solder joints 21 are arranged in a one-to-one correspondence. Each electrode contact 11 and its corresponding electrode solder joint 21 are connected by a conductive line 3, and different conductive lines 3 are insulated from each other. In this embodiment, the area with electrode contacts 11 on the medical implantable ECoG electrode 100 can be used for implantation into the subdural dermis. The electrode contacts 11 are used for signal acquisition, and the electrode solder joints 21 are used to connect to external devices (e.g., soldering electrode solder joints 21 to an FPC connector). The subdural dermis signal acquired by the electrode contacts 11 is transmitted to the external device via the conductive line 3 and the electrode solder joint 21 connected to them.

[0061] In some embodiments of this application, the shape of the electrode contact 11 is not limited. Exemplarily, the horizontal cross-section of the electrode contact 11 can be one of the following shapes: circular, square, rectangular, triangular, rhomboid, elliptical, or polygonal. Unless otherwise specified, the following description will use a circular horizontal cross-section of the electrode contact 11 (that is, the orthographic projection of the electrode contact 11 is circular) as an example.

[0062] In some embodiments of this application, the diameter of the electrode contact 11 can be between 5 μm and 15000 μm. Exemplarily, the electrode contact 11 is generally circular, and the diameter of the electrode contact 11 is 5 μm, 10 μm, 15 μm, 20 μm, 50 μm, 100 μm, 200 μm, 300 μm, 400 μm, 500 μm, 600 μm, 700 μm, 800 μm, 900 μm, 1000 μm, 2000 μm, 3000 μm, 4000 μm, 5000 μm, 6000 μm, 7000 μm, 8000 μm, 9000 μm, 10000 μm, 11000 μm, 12000 μm, 13000 μm, 14000 μm, 15000 μm, or any two of the above values. It should be noted that in some other embodiments of this application, the electrode contact 11 may not be circular. For example, the electrode contact 11 may be triangular, square, elliptical, etc. In this case, the diameter of the electrode contact 11 can be understood as the diameter of its equivalent circle.

[0063] Furthermore, the diameter of the electrode contact is between 5 μm and 2500 μm. Further, the diameter of the electrode contact 11 can be between 100 μm and 500 μm. In this application, the electrode contact 11 is designed to be at the micrometer level, allowing it to more closely approximate neuronal tissue and its size to be closer to the cortical functional columns of our research subject. The size of the cortical functional columns is between 100 μm and 500 μm, and they are considered the basic units of information processing. The size of the electrode contact 11 in this application enables higher spatial resolution and finer information, and has better biocompatibility.

[0064] Please refer to some embodiments of this application. Figure 5 The electrode contact 11 includes a large contact 112 and a small contact 111, the area of ​​which is smaller than that of the large contact 112. The small contact 111 is used for signal acquisition, and the large contact 112 is used for electrical stimulation. Exemplarily, both the small contact 111 and the large contact 112 are circular, ranging from 5 μm to 500 μm. Further, the diameter of the small contact 111 is 10 μm to 200 μm. The diameter of the large contact 112 is 500 μm to 8000 μm. Further, the diameter of the large contact 112 is 500 μm to 2500 μm.

[0065] In some embodiments of this application, the electrode contact 11 includes at least one of platinum contact, cobalt alloy contact, gold contact, titanium contact, titanium nitride contact, tungsten contact, iridium contact, iridium oxide contact, ruthenium and its compounds contact, carbon nanotube contact, and poly(3,4-ethylenedioxythiophene) contact.

[0066] Furthermore, the electrode contact 11 includes a platinum contact, meaning that the material forming the electrode contact 11 includes platinum. It is understood that platinum has extremely high corrosion resistance, does not readily react with chemicals, has good biocompatibility, and excellent electrical conductivity. This embodiment uses platinum to prepare the electrode contact 11, which is beneficial for giving the contact electrode in this application excellent biocompatibility, conductivity, and stability.

[0067] In some embodiments of this application, the shape, size, and material of the electrode solder joint 21 are not limited. Exemplarily, the horizontal cross-section of the electrode solder joint 21 is one of a circular, square, rectangular, triangular, rhomboid, elliptical, or polygonal shape.

[0068] In some embodiments of this application, the electrode solder joint 21 includes at least one of gold solder joint, platinum solder joint, aluminum solder joint, tungsten solder joint, titanium solder joint, nickel solder joint, nickel solder joint, and copper solder joint. That is, the material forming the electrode solder joint 21 may include at least one of gold, platinum, aluminum, tungsten, titanium, nickel, nickel, and copper.

[0069] Furthermore, the electrode solder joint 21 includes a gold solder joint, that is, the material used to prepare the electrode solder joint 21 is gold. It is understood that gold has excellent welding strength and stability. In this embodiment, using gold as the material to prepare the electrode solder joint 21 is beneficial to improving the quality of the signal acquired by the prepared medical implantable ECoG electrode 100, and improving the stability of the electrical connection between the medical implantable ECoG electrode 100 and external devices.

[0070] In some embodiments of this application, the thickness of the electrode layer 5 can be between 1 nanometer and 2000 nanometers. Exemplarily, the thickness of the electrode layer 5 is 1 nanometer, 10 nanometers, 15 nanometers, 20 nanometers, 50 nanometers, 100 nanometers, 200 nanometers, 300 nanometers, 400 nanometers, 500 nanometers, 600 nanometers, 700 nanometers, 800 nanometers, 900 nanometers, 1000 nanometers, 1100 nanometers, 1200 nanometers, 1300 nanometers, 1400 nanometers, 1500 nanometers, 1600 nanometers, 1700 nanometers, 1800 nanometers, 1900 nanometers, 2000 nanometers, and any value between any two of the above.

[0071] For example, the thickness of electrode layer 5 is 10 to 1000 nanometers. In this way, electrode layer 5 has good stability and reliability.

[0072] In some embodiments of this application, the number of electrode contacts 11 is multiple, and the multiple electrode contacts 11 are arranged in an array. Exemplarily, the number of electrode contacts 11 is from 16 to 1024. In this way, the recording and / or stimulation effect of the electrode is good. For example, the number of electrode contacts 11 is 32, 64, 128, or 256.

[0073] Furthermore, there are multiple electrode contacts 11, and multiple electrode solder points 21 are arranged in an array. For example, the number of electrode contacts 11 is the same as the number of electrode solder points 21. In this way, it is convenient to connect using conductive wires 3.

[0074] In some embodiments of this application, the width of the central region of the conductive line 3 is smaller than the width of the electrode contact region 1 and the width of the pad region, and the width of the pad region is smaller than the width of the electrode contact region 1. This improves the compactness of the ECoG electrode layout and facilitates the miniaturization of the ECoG electrode.

[0075] In some embodiments of this application, the materials used to prepare the electrode contacts 11 and the electrode solder joints 21 are the same. Furthermore, the materials used to prepare the electrode contacts 11, electrode solder joints 21, and conductive wires 3 are the same. Thus, the electrode layer 5 can be prepared in a single thin-film deposition process. For example, the materials used to prepare the electrode contacts 11 and electrode solder joints 21 are both platinum; another example is that the materials used to prepare the electrode contacts 11 and electrode solder joints 21 are both gold.

[0076] It should be noted that the thin film deposition process can include any one of electron beam evaporation, thermal evaporation, and magnetron sputtering. The thin film deposition process is not a major improvement of this application and is not limited thereto.

[0077] In some embodiments of this application, the electrode layer 5 is formed by a single thin film deposition process; accordingly, please refer to [link to relevant documentation]. Figure 9The electrode layer 5 in the medical implantable ECoG electrode 100 is a single metal layer.

[0078] In some embodiments of this application, in order to fully leverage the advantages of different materials and further optimize the performance of the medical implantable ECoG electrode 100, the materials used to prepare the electrode contact 11 and the electrode solder joint 21 are different. For example, the material used to prepare the electrode contact 11 is platinum, and the material used to prepare the electrode solder joint 21 is gold. This allows the exposed surfaces of the electrode contact 11 and the electrode solder joint 21 (i.e., the parts of the electrode contact 11 and the electrode solder joint 21 not covered by the encapsulation layer 6) to be made of different materials.

[0079] For example, the exposed surfaces of electrode contact 11 and electrode solder joint 21 can be made of different materials through multiple (two or more) thin film deposition processes.

[0080] Specifically, photoresist can be deposited on the flexible electrode substrate 4, covering a portion of the surface of the flexible electrode substrate 4. Surfaces of the flexible substrate 4 not covered by the photoresist include the locations of electrode contacts 11, and / or conductive lines 3, and / or electrode solder joints 21. Then, a first metal layer 51 is obtained by depositing a first metal material on the photoresist using a first thin-film deposition process. The first metal layer 51 covers at least one of the electrode contacts 11 and electrode solder joints 21 (i.e., the first metal layer 51 includes at least one of the electrode contact 11 layer and the electrode solder joint 21 layer). A second metal layer 52 is obtained by depositing a second metal material on the photoresist using a second thin-film deposition process. The second metal layer 52 covers the other of the electrode contacts 11 and electrode solder joints 21 (i.e., the second metal layer 52 includes the other of the electrode contact 11 layer and the electrode solder joint 21 layer). The first metal material and the second metal material are different. It should be noted that the first metal layer 51 covering at least one of the electrode contact 11 and the electrode solder joint 21 may be that the first metal layer 51 only covers the electrode contact 11, or the first metal layer 51 only covers the electrode solder joint 21, or the first metal layer 51 may cover both the electrode contact 11 and the electrode solder joint 21. No limitation is made here.

[0081] For example, a first photoresist layer is formed on a flexible substrate 4. The surface of the flexible substrate 4 not covered by the first photoresist includes only the electrode contacts 11. Then, a first thin film deposition process is performed to deposit a first metal layer 51 on the flexible substrate 4 and the first photoresist. Then, the first photoresist layer and the first metal layer 51 located on the first photoresist are removed to obtain a flexible substrate 4 with electrode contacts 11 (at this time, the first metal layer 51 only covers the area where the electrode contacts 11 are located). Then, a second photoresist layer is formed on the flexible substrate 4. The surface of the flexible substrate 4 not covered by the second photoresist includes only the area where the electrode solder joint 21 is located, the area where the conductive line 3 is located, and the area where the conductive line 3 is connected to the electrode contacts 11. Then, a second thin film deposition process is performed to deposit a second metal layer 52 on the flexible substrate 4 and the second photoresist. At this time, the second metal layer 52 covers the area where the electrode solder joint 21 is located, the area where the conductive line 3 is located, and the area where the conductive line 3 is connected to the electrode contacts 11. The first metal layer 51 and the second metal layer 52 together form the electrode layer 5.

[0082] Similarly, in other embodiments, the first metal layer 51 covers the area where the electrode contact 11 is located and the area where the conductive line 3 is located, and the second metal layer 52 covers the area where the electrode solder joint 21 is located and the area where the conductive line 3 is located. The first metal layer 51 and the second metal layer together form the electrode layer 5, that is, each conductive line 3 includes two metal layers (the first metal layer 51 and the second metal layer 52) stacked together. For example, the first metal layer 51 covers the area where the electrode contact 11 is located, the area where the conductive line 3 is located, and the area where the electrode solder joint is located, and the second metal layer 52 covers the area where the electrode solder joint 21 is located, or the area where the electrode solder joint is located and the area where the conductive line 3 is located, etc., etc., which are not limited here.

[0083] It is understandable that during the entire manufacturing process of the medical implantable ECoG electrode 100, such as the process of depositing the first metal material to obtain the first metal layer 51, dust particles or impurities will inevitably exist, which will cause the conductive wire 3 at the location of the dust particles to break, and there will be no conductivity between the electrode contact 11 and the corresponding electrode solder joint 21, thus causing the signal collected by the electrode contact 11 connected to the conductive wire 3 to be unable to be transmitted.

[0084] In some embodiments of this application, the electrode layer 5 includes a first metal layer 51 and a second metal layer 52 stacked together. The first metal layer 51 includes a plurality of first conductive lines, and the second metal layer 52 includes a plurality of second conductive lines. The first conductive lines and the second conductive lines are arranged in a one-to-one correspondence. The first conductive lines and the corresponding second conductive lines at least partially overlap. That is, each conductive line 3 in the embodiments of this application includes a first conductive line and a second conductive line stacked together.

[0085] In this embodiment, a first metal layer 51 and a second metal layer 52 are provided at the location of the conductive wire 3. The first metal layer 51 includes multiple first conductive wires, and the second metal layer 52 includes multiple second conductive wires. The first conductive wires and the second conductive wires are arranged in a one-to-one correspondence. The first conductive wires and the corresponding second conductive wires at least partially overlap. When the first conductive wire in the first metal layer 51 breaks at a certain point, the break point on the first conductive wire can be covered by the corresponding second conductive wire, thereby enabling the broken first conductive wire to conduct electricity. This effectively repairs the defect of the first conductive wire and improves the stability of the medical implantable ECoG electrode 100 product.

[0086] For example, the second metal layer 52 covers the first metal layer 51. Also, for example, the orthographic projection of the second metal layer 52 is located within the first metal layer 51. In other words, each second conductive line in the second metal layer 52 is located within a corresponding first conductive line in the first metal layer 51. Thus, each conductive line 3 in this embodiment includes a stacked first conductive line and a second conductive line. When a first conductive line in the first metal layer 51 is broken, the break can be repaired by the corresponding second conductive line in the second metal layer, allowing the broken first conductive line to conduct electricity. This effectively repairs the defects in the first metal layer, thereby improving the stability of the medical implantable ECoG electrode 100 product.

[0087] Specifically, the first metal layer 51 includes a platinum layer, which covers the area where the electrode contact 11, the area where the electrode solder joint 21, and the area where the conductive line 3 are located. The second metal layer includes a gold layer, which covers the area where the electrode solder joint 21 and the area where the conductive line 3 are located, so that the exposed side of the electrode contact 11 (that is, the side of the electrode contact 11 facing away from the flexible substrate 4) is made of platinum, while the exposed side of the electrode solder joint 21 (that is, the side of the electrode solder joint 21 facing away from the flexible substrate 4) is made of gold.

[0088] Furthermore, the inventors discovered that although each conductive wire 3 includes a platinum layer (i.e., the first metal layer 51) and a gold layer (i.e., the second metal layer 52) stacked together, which helps to avoid product quality instability caused by breakage of the conductive wire 3, it also easily leads to burrs at the edges of the conductive wire 3, such as... Figure 12 As shown, this affects the appearance of the product and, in severe cases, can even cause two adjacent conductive lines 3 to become connected.

[0089] In response, the inventors discovered through research that during the deposition of a gold layer (i.e., a second metal layer 52) on a platinum layer (i.e., the first metal layer 51), a Ti (titanium) layer can be grown on the platinum layer first, and then a gold layer can be deposited on the Ti layer. This avoids the problem of burrs at the edges caused by depositing a platinum layer first and then a gold layer at the location of the conductive line 3.

[0090] The applicant also discovered that during the deposition of the second metal layer (e.g., gold layer) 52 on the first metal layer (e.g., platinum layer) 51, if the second metal layer (e.g., gold layer) 52 is directly deposited on the first metal layer (e.g., platinum layer) 51, and the pattern of the deposited second metal layer (e.g., gold layer) 52 is completely within the pattern area of ​​the first metal layer (e.g., platinum layer) 51, it also helps to improve the problem of burrs at the edges of the conductive lines 3. Specifically, taking the first metal layer 51 including a first conductive line, the second metal layer 52 including a second conductive line, the second conductive line corresponding one-to-one with the first conductive line, and the second conductive line and the corresponding first conductive line being stacked as an example, if the second conductive line is located within the first conductive line, the prepared product is as follows: Figure 13 As shown, this also helps to improve the problem of burrs at the edges of conductive wire 3.

[0091] Furthermore, the distance between the edge of the second conductive line and the edge of the adjacent first conductive line is 1 μm or more, which helps to further solve the problem of burrs at the edge of the conductive line 3. Specifically, the material used to prepare the first metal layer 51 includes platinum material, which covers the area where the electrode contact 11 and the conductive line 3 are located. Then, the photoresist and the platinum material on the photoresist are removed to obtain the first metal layer (i.e., the platinum layer) on the flexible substrate 4, wherein the first metal layer 51 includes patterned electrode contacts 11 and conductive lines 3. It should be noted that the first metal layer may include a single sub-metal layer (e.g., a platinum layer) or multiple sub-metal layers (i.e., multiple sub-metal layers formed in a single thin film deposition process), which is not limited here. Then, photoresist is applied to the first metal layer, covering a portion of the surface of the first metal layer. For example, the photoresist covers the area excluding the conductive line 3 and the electrode solder joint 21, and then a Ti layer and a gold layer are sequentially deposited on the photoresist through a single thin film deposition process. Then, the photoresist is removed to form the electrode layer 5 on the flexible substrate 4.

[0092] In this embodiment, the encapsulation layer 6 is disposed on the side of the electrode layer 5 facing away from the flexible substrate 4. The encapsulation layer 6 covers the flexible substrate 4 and the electrode layer 5 except for the locations of the electrode contacts 11 and the electrode solder joints 21. That is, the encapsulation layer 6 does not cover the side of the electrode contacts 11 facing away from the flexible substrate 4, thereby enabling the electrode contacts 11 exposed outside the encapsulation layer 6 to acquire signals. The encapsulation layer 6 also does not cover the side of the electrode solder joints 21 facing away from the flexible substrate 4, thereby enabling the electrode solder joints 21 to be electrically connected to external devices.

[0093] Please refer to some embodiments of this application. Figure 6 and Figure 7, a plurality of contact openings 61 are provided on the encapsulation layer 6, and the electrode contacts 11 are exposed in the corresponding contact openings 61. The orthographic projection of the contact opening 61 on the plane where the electrode contact 11 is located is located within the contour line of the corresponding electrode contact 11. The minimum distance between the contour line of the orthographic projection of the contact opening 61 on the plane where the electrode contact 11 is located and the contour line of the electrode contact 11 is d, and d satisfies not less than 3 microns (that is, the minimum distance d between the orthographic projection of the contact opening 61 on the plane where the electrode contact 11 is located and the contour line of the electrode contact 11 is greater than or equal to 3 microns). The inventor found through experiments that the ECoG electrode 100 implanted in the human body in the related art has the problem of poor durability. For example, after the ECoG electrode 100 implanted in the human body is implanted into the body, its electrode contacts 11 are prone to deformation and failure. In this embodiment, by making the orthographic projection of the contact opening 61 on the plane where the electrode contact 11 is located be located within the contour line of the corresponding electrode contact 11, and the minimum distance d between the orthographic projection of the contact opening 61 on the plane where the electrode contact 11 is located and the contour line of the electrode contact 11 is not less than 3 microns, the durability of the ECoG electrode 100 implanted in the human body can be effectively improved.

[0094] In some embodiments of the present application, the minimum distance d between the contour line of the orthographic projection of the contact opening 61 on the plane where the electrode contact 11 is located and the contour line of the electrode contact 11 is 3 microns to 100 microns. Exemplarily, d is 3 microns, 5 microns, 10 microns, 20 microns, 30 microns, 40 microns, 50 microns, 60 microns, 70 microns, 80 microns, 90 microns, 100 microns, and values between any two of the above values. Thus, it is beneficial to improve the durability of the ECoG electrode 100 implanted in the human body, and the ECoG electrode 100 implanted in the human body in the present application has a relatively small volume.

[0095] Furthermore, the contour line of the orthographic projection of the contact opening 61 on the plane where the electrode contact 11 is located and the contour line of the electrode contact 11 form a concentric ring structure, and the distance from each point on the contour line of the orthographic projection of the contact opening 61 on the plane where the electrode contact 11 is located to the electrode contact 11 is equal. Exemplarily, the electrode contact 11 is circular, the contact opening 61 and the electrode contact 11 are concentrically arranged, and the minimum distance d between the two circles is not less than 3 microns. Another example is that the electrode contact 11 is square, the contact opening 61 is also square, the two squares are generally in a "hui" shape, and the minimum distance d between the contour line of the orthographic projection of the contact opening 61 on the plane where the electrode contact 11 is located and the contour line of the electrode contact 11 is not less than 3 microns.

[0096] In some embodiments of the present application, the material of the encapsulation layer 6 may include at least one of polyimide, SU 8, silicon carbide, liquid crystal polymer, Parylene C, ceramic, and silicon dioxide. Exemplarily, the material of the encapsulation layer 6 is polyimide.

[0097] In some embodiments of this application, the medical implantable ECoG electrode 100 includes a multilayered polyimide layer (i.e., a flexible substrate 4), an electrode layer 5, and a polyimide encapsulation layer 6. The electrode layer 5 includes electrode contacts 11, electrode solder joints 21, and conductive lines 3. The conductive lines 3 include a multilayered first metal layer 51 and a second metal layer 52. The polyimide encapsulation layer 6 covers the flexible substrate 4 and also covers the area of ​​the electrode layer 5 excluding the areas where the electrode contacts 11 and electrode solder joints 21 are located. The medical implantable ECoG electrode 100 in this embodiment has good flexibility and biocompatibility.

[0098] Please refer again to some embodiments of this application. Figure 6 A hollow portion 12 is provided between two adjacent electrode contacts 11 on the electrode contact area 1, excluding the position of the conductive line 3. The hollow portion 12 penetrates the top and bottom surfaces of the electrode contact area 1, that is, the hollow portion 12 penetrates the electrode layer 5 located in the electrode contact area 1.

[0099] In some embodiments of this application, the medical implantable ECoG electrode further includes an adhesive layer disposed between the flexible substrate and the encapsulation layer and / or between the flexible substrate and the electrode layer.

[0100] For example, please refer to Figure 8 An adhesive layer 7 is provided between the encapsulation layer 6 and the flexible substrate 4. The inventors have discovered that in related technologies, after the medical implantable ECoG electrode 100 is implanted in the body, the encapsulation layer 6 and the flexible substrate 4 are prone to separation, deformation, and failure. This embodiment, by providing an adhesive layer 7 between the encapsulation layer 6 and the flexible substrate 4, helps to prevent separation between the encapsulation layer 6 and the flexible substrate 4, thereby improving the durability of the medical implantable ECoG electrode 100. For example, a very thin adhesive layer 7 can be spin-coated onto the surface of the flexible substrate 4 to achieve the effect of improving the tight adhesion between the support layer and the encapsulation layer 6.

[0101] For example, the tackifying layer 7 can be formed by chemical treatment methods, chemical vapor deposition, atomic layer deposition or physical vapor deposition, oxygen plasma treatment, etc. It should be noted that the preparation process of the tackifying layer 7 can adopt existing molding methods, and is not limited here.

[0102] In other embodiments of this application, the adhesive layer may also be disposed between the flexible substrate and the electrode layer, thereby increasing the adhesion between the flexible substrate and the electrode layer. Of course, adhesive layers may also be disposed between the flexible substrate and the encapsulation layer, and between the flexible substrate and the electrode layer; this is not limited to this application.

[0103] For example, the tackifying layer 7 is at least one of the following: chromium layer, silane coupling agent layer, silicon carbide layer, amorphous silicon carbide (a-SiC:H) layer, diamond-like carbon (DLC) layer, amorphous carbon (aC:H) layer, silicon nitride layer, silicon oxynitride layer, and silicon oxycarbide layer.

[0104] It should be noted that these materials, acting as adhesion-enhancing layers, help improve the performance and stability of ECoG electrodes while ensuring long-term biocompatibility. For example, silane coupling agents can form strong chemical bonds between the electrode layer and the flexible substrate, improving adhesion strength and significantly enhancing the composite material's performance. Silicon carbide layers and amorphous silicon carbide layers are chemically stable and non-biotoxic, and can improve the adhesion between the metal and flexible substrate interfaces through appropriate treatment. Amorphous carbon layers also exhibit good chemical stability and mechanical properties, demonstrating good biocompatibility in biological environments without causing excessive inflammation or tissue reactions. They can form strong adhesion with polyimide and can also exhibit different conductivity properties depending on their structure and composition, allowing for more flexible design. Silicon nitride and silicon oxycarbide layers have good wear resistance and chemical stability; silicon oxynitride layers combine good dielectric properties and mechanical strength, good adhesion, and environmental stability.

[0105] In some embodiments of this application, the thickness of the adhesive layer 7 is from 5 nanometers to 1 micrometer. Exemplarily, the thickness of the adhesive layer 7 is 5 nanometers, 10 nanometers, 20 nanometers, 30 nanometers, 50 nanometers, 100 nanometers, 200 nanometers, 500 nanometers, 800 nanometers, or 1 micrometer. If the thickness of the adhesive layer is too low, for example, less than 5 nanometers, its adhesive effect is not ideal; if the thickness of the adhesive layer is too high, for example, greater than 1 micrometer, it can easily lead to poor product flexibility.

[0106] Example 1

[0107] A polyimide layer with a thickness of 10 micrometers is fabricated on a silicon substrate. Then, a conductive layer with a thickness of 20 nanometers is fabricated on the polyimide layer. The conductive layer includes multiple electrode contacts, multiple electrode solder joints, and multiple conductive lines. An encapsulation layer is fabricated on the conductive layer. The multiple electrode contacts are of the same size, each electrode contact is circular, has a diameter of 200 μm, and a contact opening diameter of 196 μm.

[0108] Comparative Example 1

[0109] The difference between it and implementation 1 is that the diameter of the contact opening is 199um.

[0110] Aging test: The sample was immersed in PBS solution for aging test at a temperature of 90 degrees Celsius and a pH of 7.4.

[0111] Table 1

[0112] Example 1 The edges of the electrode contacts are corroded. Comparative Example 1 No corrosion was found at the edges of the electrode contacts.

[0113] The medical implantable ECoG electrodes from Example 1 and Comparative Example 1 were subjected to aging tests, and the test results are as follows: Figure 10 , Figure 11 As shown in Table 1, when d is not greater than or equal to 3 micrometers, significant corrosion occurs at the electrode contact edges of the medical implanted ECoG electrode after the aging test, indicating poor durability. When d is greater than or equal to 3 micrometers, no corrosion occurs at the electrode contact edges of the medical implanted ECoG electrode after the aging test, indicating good durability.

[0114] The technical solutions provided by the embodiments of this application have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A medical implantable ECoG electrode, characterized in that, The medical implantable ECoG electrode includes a flexible substrate, an electrode layer, and an encapsulation layer; The electrode layer is disposed on one side of the flexible substrate. The electrode layer includes a plurality of electrode contacts, a plurality of electrode solder joints, and a plurality of conductive lines. The plurality of electrode contacts and the plurality of electrode solder joints are arranged in a one-to-one correspondence. Each conductive line is electrically connected to the electrode contact and the corresponding electrode solder joint. The encapsulation layer covers the flexible substrate and the electrode layer; the encapsulation layer has a contact opening, the electrode contact is exposed in the contact opening, and the orthographic projection of the contact opening on the plane where the electrode contact is located is located within the outer contour of the electrode contact; the minimum distance between the contour line of the orthographic projection of the contact opening on the plane where the electrode contact is located and the contour line of the electrode contact within it is d, where d is greater than or equal to 3 micrometers.

2. The medical implantable ECoG electrode as described in claim 1, characterized in that, The value of d is greater than or equal to 3 micrometers and less than or equal to 100 micrometers.

3. The medical implantable ECoG electrode as described in claim 1 or 2, characterized in that, The electrode layer includes a first metal layer and a second metal layer stacked together.

4. The medical implantable ECoG electrode as described in claim 3, characterized in that, The flexible substrate is a polyimide layer, the first metal layer includes a first titanium layer and a first sub-metal layer; the second metal layer includes a second titanium layer and a second sub-metal layer, and neither the first sub-metal layer nor the second sub-metal layer is a titanium metal layer. The polyimide layer, the first titanium layer, the first sub-metal layer, the second titanium layer, and one side of the second sub-metal layer are stacked.

5. The medical implantable ECoG electrode as described in claim 4, characterized in that, The first sub-metal layer includes a first platinum layer, the second sub-metal layer includes a second platinum layer and a gold layer, and the polyimide layer, the first titanium layer, the first platinum layer, the second titanium layer, the second platinum layer and the gold layer are stacked sequentially.

6. The medical implantable ECoG electrode as described in claim 4, characterized in that, The first sub-metal layer includes a first platinum layer, the second sub-metal layer includes a gold layer, and the polyimide layer, the first titanium layer, the first platinum layer, the second titanium layer, and the gold layer are stacked sequentially.

7. The medical implantable ECoG electrode as described in claim 3, characterized in that, The first metal layer and the second metal layer are independently selected from cobalt alloy layer, gold layer, platinum layer, titanium and its compound layer, tungsten layer, iridium and its compound layer, and ruthenium and its compound layer, respectively.

8. The medical implantable ECoG electrode as described in claim 1, characterized in that, The electrode contacts include at least one of the following: platinum contacts, cobalt alloy contacts, gold contacts, titanium contacts, titanium nitride contacts, tungsten contacts, iridium contacts, iridium oxide contacts, ruthenium and its compounds contacts, carbon nanotube contacts, and poly(3,4-ethylenedioxythiophene) contacts; and / or The electrode solder joints include at least one of the following: gold solder joints, platinum solder joints, aluminum solder joints, tungsten solder joints, titanium solder joints, nickel solder joints, tin solder joints, and copper solder joints.

9. The medical implantable ECoG electrode as described in any one of claims 1 to 3, characterized in that, The electrode contacts include large contacts and small contacts; and / or The electrode contacts are circular, and the diameter of the electrode contacts is from 5 μm to 2500 μm; and / or The electrode layer includes multiple electrode contacts, which are arranged in an array; and / or The electrode layer includes multiple electrode solder joints, which are arranged in an array.

10. The medical implantable ECoG electrode as described in claim 9, characterized in that, The large contact is circular, and its diameter is between 500 μm and 2500 μm; and / or The small contact is circular, and the diameter of the small contact is from 5um to 500um.

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