CN115662681A - Flexible electrode integrated with feed-through substrate, preparation method of flexible electrode and electrode device - Google Patents
Flexible electrode integrated with feed-through substrate, preparation method of flexible electrode and electrode device Download PDFInfo
- Publication number
- CN115662681A CN115662681A CN202211394183.0A CN202211394183A CN115662681A CN 115662681 A CN115662681 A CN 115662681A CN 202211394183 A CN202211394183 A CN 202211394183A CN 115662681 A CN115662681 A CN 115662681A
- Authority
- CN
- China
- Prior art keywords
- layer
- substrate
- redistribution
- electrode
- feed
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Images
Abstract
The invention provides a flexible electrode integrated with a feed-through substrate, a preparation method thereof and an electrode device, wherein the flexible electrode comprises the following components in sequence: a flexible electrode having an electrode conductive layer; the feed-through substrate is internally provided with a conductive micro-column array, the top surface and the bottom surface of the feed-through substrate are both provided with insulating layers, and the outer surface of each insulating layer is provided with a substrate bonding pad; the redistribution layer is provided with a redistribution conductive layer and a redistribution bonding pad connected with the redistribution conductive layer, an external circuit is connected through the redistribution bonding pad, and the electrode conductive layer, the conductive micro-column array, the substrate bonding pad and the redistribution conductive layer are electrically connected. The invention can realize the integrated MEMS flow sheet processing mode of the device, and has high processing consistency and good biocompatibility.
Description
Technical Field
The invention relates to the technical field of flexible electrodes, in particular to a flexible electrode integrated with a feed-through substrate, a preparation method of the flexible electrode and an electrode device.
Background
The brain-computer interface technology provides a brain-external communication mode, which bypasses peripheral nerves and muscle tissues and directly transmits signals of the brain to the outside through implanted electronic equipment or transmits external information to the brain in a stimulation mode. Based on the mode, some patients suffering from limb disabilities, muscular atrophy or paralysis caused by peripheral nerve injury can directly read the electrical signals of the brain through a brain-computer interface to realize neural connection or connection with external auxiliary equipment, and regain motor and sensory functions.
Electronic devices implanted in animals and humans can be divided into physiological signal acquisition electrodes and signal processing systems from the perspective of signal acquisition. With the development of the MEMS technology, many silicon-based electrodes and flexible polymer electrodes are emerging, which have the characteristics of small volume and high density of channels. The flexible polymer electrode has a Young modulus closer to biological tissues, can conform to tiny movements of the tissues and has better long-term stability.
On the other hand, the compatibility of the flexible electrode and the IC process is far less than that of the silicon-based electrode, so that the encapsulation bonding of the flexible electrode and the subsequent signal processing system is more slowly developed than the silicon-based electrode. For example, in the paper "Time Multiplexed reactive Neural Probe with 1356Parallel Recording Sites" published by IMEC corporation in 2017, silicon-based implantable Probe and IC signal processing circuit are integrated on a silicon-on-one needle, and the integrated flow sheet process is completed. While the book "A miniature 256-Channel neutral Recording Interface With Area-Efficient Hybrid Integration of Flexible Probes and CMOS Integrated Circuits" published by Sun-Yun Park et al in 2022 encapsulates the Flexible electrodes With ASIC chips by flip-chip bonding and interposer bonding solder balls having a diameter of 75 μm. And other bonding processes such as wire bonding and ball grid array not only have large bonding volume, but also the adapter plate needs to be manufactured separately, so that the integrated tape flow with the flexible electrode cannot be realized, and the process complexity is increased.
Disclosure of Invention
In view of the drawbacks of the prior art, it is an object of the present invention to provide a flexible electrode integrated with a feed-through substrate, a method for manufacturing the same, and an electrode device.
According to a first aspect of the present invention, there is provided a flexible electrode integrated with a feed-through substrate, the flexible electrode comprising, in order:
a flexible electrode having an electrode conductive layer;
the feed-through substrate is internally provided with a conductive micro-column array, the top and bottom surfaces of the feed-through substrate are provided with insulating layers, and the outer surface of each insulating layer is provided with a substrate bonding pad;
the redistribution layer is provided with a redistribution conductive layer and a redistribution bonding pad connected with the redistribution conductive layer, an external circuit is connected through the redistribution bonding pad, and the electrode conductive layer, the conductive micro-column array, the substrate bonding pad and the redistribution conductive layer are electrically connected.
Further, the feed-through substrate comprises any one of a ceramic feed-through substrate, a glass feed-through substrate, and a silicon-based feed-through substrate.
Further, the thickness of the electrode conducting layer is 0.01-1 μm.
Further, the thickness of the substrate bonding pad is 0.5-5 μm, and the insulating layer is made of any one of silicon dioxide, silicon carbide, aluminum oxide and zirconium oxide.
Further, the thickness of the redistribution conductive layer is 1-10 μm.
According to a second aspect of the present invention, there is provided a method of manufacturing a flexible electrode of an integrated feed-through substrate as described above, the method comprising:
forming a substrate having an array of microwells;
filling a conductive material in the micropores of the micropore array, and flattening the surface of the substrate to form a feed-through substrate;
forming an insulating layer on a first surface of the feed-through substrate and a second surface opposite to the first surface, and forming a substrate pad on the insulating layer;
placing the feed-through substrate to enable the first surface to be located on the second surface, and spin-coating a flexible polymer on the first surface to form a flexible electrode base layer; patterning the flexible electrode base layer to expose the substrate bonding pad;
sputtering and forming an electrode metal layer on the flexible electrode substrate layer; a photoresist mask is spin-coated on the electrode metal layer, and an electrode conducting layer is obtained through imaging after exposure and development;
spin-coating a flexible polymer on the electrode conductive layer to form a flexible electrode packaging layer;
turning over the feed-through substrate to enable the second surface to be located on the first surface, and spin-coating a flexible polymer on the second surface to form a redistribution base layer;
according to the lead layout of the redistribution layer, sequentially patterning, sputtering a metal layer, spin-coating a mask on the redistribution base layer, exposing and developing, and then patterning to form a redistribution lead layer;
spin coating a flexible polymer on the redistribution lead layer to form a redistribution packaging layer; and patterning the redistribution encapsulation layer to expose the redistribution pads.
Further, the single-layer thickness of the flexible electrode base layer and the flexible electrode packaging layer is 0.2-20 μm.
Further, spin coating a flexible polymer on the second surface to form a redistribution substrate layer, wherein: the redistribution layer is made of a flexible polymer doped with thermally conductive particles to improve thermal conductivity.
Further, the single-layer thickness of the redistribution layer substrate layer and the redistribution layer packaging layer is 5-10 μm; the total thickness of the redistribution layer is 10-50 μm.
According to a third aspect of the invention, an electrode device is provided comprising an ASIC chip and the above-mentioned flexible electrode of the integrated feed-through substrate, the ASIC chip being connected with the redistribution pads.
Compared with the prior art, the invention has the following beneficial effects:
1. the biocompatible flexible electrode adopted by the invention not only has the advantages of small volume and high channel number of the silicon-based probe, but also has the Young modulus closer to biological tissues, can conform to the micromotion of the biological tissues, reduces implantation damage and realizes the function of acquiring long-term physiological signals.
2. In the integrated preparation method, the bonding encapsulation of the flexible electrode and the adapter plate (namely the electrical interconnection feed-through substrate) is completed under the MEMS process, so that the bonding process flow and the bonding difficulty are simplified, and the integrated tape-out process can realize high-controllability and high-repeatability processing.
3. In the integrated preparation method, the electrical connection between the flexible electrode and the feed-through substrate is realized through the metal bonding pad, compared with the conventional solder ball connection mode, the size of the bonding pad is greatly reduced, the bonding characteristic length in practice can be within 10 mu m, and the density and the integration level of the sealed feed-through are improved.
4. The redistribution layer is deposited on the back of the feed-through substrate, so that the feed-through substrate can adapt to the pin distribution of different ASIC chips, and the application range and application scene of integrated feed-through and flexible electrode devices are enlarged.
Drawings
Other features, objects and advantages of the invention will become more apparent upon reading of the detailed description of non-limiting embodiments with reference to the following drawings:
FIG. 1 is a schematic bottom view of a flexible electrode integrated with a feedthrough substrate in accordance with one embodiment of the present invention;
FIG. 2 is a schematic top view of a flexible electrode integrated with a feedthrough substrate in accordance with one embodiment of the present disclosure;
FIG. 3 is a schematic diagram of an ASIC chip electrically interconnected to a flex electrode according to one embodiment of the present invention;
fig. 4 is a schematic flow chart of a method for manufacturing a flexible electrode integrated with a feed-through substrate according to an embodiment of the invention;
fig. 5 is a schematic structural diagram corresponding to each step of a method for manufacturing a flexible electrode integrated with a feed-through substrate according to an embodiment of the invention.
In the figure: the feed-through substrate is 1, the conductive microcolumn is 101, the flexible electrode is 2, the flexible electrode pad is 201, the redistribution layer is 3, the physiological signal input pad is 301, the ASIC redistribution pad is 302, and the ASIC chip is 4.
Detailed Description
The present invention will be described in detail with reference to specific examples. The following examples will assist those skilled in the art in further understanding the invention, but are not intended to limit the invention in any way. It should be noted that variations and modifications can be made by persons skilled in the art without departing from the spirit of the invention. All falling within the scope of the present invention.
The embodiment of the invention provides a flexible electrode integrated with a feed-through substrate, and referring to fig. 1-2, the flexible electrode comprises a flexible electrode 2, a feed-through substrate 1 and a redistribution layer 3 (RDL) which are arranged in sequence, wherein the flexible electrode 2 is provided with an electrode conducting layer; a conductive micro-column array formed by conductive micro-columns 101 is arranged in the feed-through substrate 1, insulating layers are arranged on the top and bottom surfaces of the feed-through substrate 1, and substrate bonding pads are arranged on the outer surfaces of the insulating layers; the redistribution layer 3 is provided with a redistribution conductive layer and a redistribution pad connected with the redistribution conductive layer, an external circuit is connected through the redistribution pad, and the electrode conductive layer, the conductive micro-column array, the substrate pad and the redistribution conductive layer are electrically connected, so that electric interconnection feed-through is realized.
In some embodiments, the feed-through substrate 1 comprises any one of a ceramic feed-through substrate, a glass feed-through substrate, and a silicon-based feed-through substrate. The conductive microcolumn 101 is formed by filling a conductive material, wherein the conductive material is filled by electroplating or sintering and hot-pressing.
The problem of device failure caused by a gap possibly existing between the feed-through substrate 1 and the conductive micro-pillars 101 can be solved by depositing an insulating layer on each of the upper and lower surfaces of the feed-through substrate 1. The diameter of the insulating layer through hole 3 is 1-20um smaller than that of the conductive microcolumn 101. The insulating layer is provided with small holes at the conductive micro-pillars 101, so that the insulating layer can cover the gaps between the feed-through substrate 1 and the conductive micro-pillars 101 and can maintain the electrical connection between the conductive micro-pillars 101 and the flexible electrodes 2 or the redistribution layer 3.
The feed-through substrate 1 in the above embodiment is formed by the MEMS process, and can realize a processing line width of a micrometer scale, thereby having a high density feed-through number; the through hole of the insulating layer covers the gap between the conductive microcolumn 101 and the substrate, strengthens the cracks possibly existing on the contact surface of different materials, and has the characteristic of high sealing property; the through holes of the insulating layer can be formed through a reverse die technology, and the smoothness and the uniformity of a die are improved through a high-precision processing mode, so that the appearance uniformity of the ceramic through holes is improved. The feed-through substrate 1 has the advantages of high-density feed-through number, high sealing performance, uniform through hole appearance and the like.
In some embodiments, poor solder joint results due to too small a substrate pad; the substrate pad is too large to increase the impedance, and preferably has a thickness of 0.5-5 μm, and the substrate pad is made of a material including but not limited to titanium, platinum, chromium, gold, or an alloy thereof.
In some embodiments, the flexible electrode 2 and the redistribution layer 3 each comprise a polymer base layer, a metal layer (conductive layer), a polymer encapsulation layer. The thickness of the electrode conducting layer is 0.01-1 μm, the electrode conducting layer of the flexible electrode 2 comprises a flexible electrode pad 201, one end of the electrode conducting layer is an electrode collecting point, and the other end of the electrode conducting layer is the flexible electrode pad 201; the material of the conductive layer includes, but is not limited to, titanium, platinum, chromium, gold, or an alloy therebetween, and the material adopted by the polymer encapsulation layer of the flexible electrode 2 includes, but is not limited to, PDMS, PI, SU-8, parylene, and the like.
In some embodiments, the redistribution conductive layer has a thickness of 1-10 μm. One end of the redistribution conductive layer is connected with the substrate pad, and the other end is exposed to be a redistribution pad, and the redistribution layer pad comprises a physiological signal input pad 301 and an ASIC redistribution pad 302. Materials used for the polymer encapsulation layer of the redistribution layer 3 include, but are not limited to, PDMS, PI, SU-8, parylene, and the like. In consideration of the problems of heat accumulation in ASIC chip power consumption and difficult heat dissipation of conventional polymers, the flexible polymer used in the redistribution layer 3 is doped with heat conductive particles to improve heat conductivity, wherein the heat conductive particles include, but are not limited to, aluminum nitride, silver nanowires, carbon nanotubes, and the like.
In some embodiments, the flexible polymeric substrate layer and the encapsulation layer are between 0.2 μm and 20 μm, more preferably between 1 μm and 20 μm, in monolayer thickness, depending on the polymeric material used, since the more flexible the polymeric substrate layer and the encapsulation layer are, the less damaging the tissue when implanted in an animal, but too soft for manual manipulation. Because the redistribution layer base layer and the packaging layer are too thick to facilitate heat dissipation, and too thin to facilitate subsequent connection with an ASIC chip, the single-layer thickness of the redistribution layer base layer and the packaging layer is between 5 and 10 mu m according to different polymer materials, and the total thickness of the redistribution layer is between 10 and 50 mu m according to the number of conductive layers of the redistribution layer.
In the embodiment of the present invention, the polymer layers of the feed-through substrate 1, the insulating layer, the flexible electrode 2 and the redistribution layer 3 are made of inert materials with good biocompatibility. The conductive microcolumn 101 is covered by a metal pad and a conductive layer formed by depositing materials such as titanium, chromium, gold and the like, so that the biotoxicity of the conductive microcolumn is further isolated. Thereby, the biological tissue safety and the long-term stability of the function of the integrated feed-through substrate 1 and the flexible electrode device can be ensured.
The flexible electrode in the embodiment can be processed and formed through an MEMS (micro electro mechanical system) process, and the packaging layer is formed by using the soft polymer, so that the flexible electrode not only has the advantages of small volume and high channel number of the silicon-based probe, but also has the Young modulus closer to the biological tissue, can conform to the micro-motion of the biological tissue, reduces implantation damage, and realizes the long-term physiological signal acquisition function. The minimum size of the ball bonding process in the prior art is about 50um, the electrical connection between the flexible electrode 2 and the feed-through substrate 1 is realized through the flexible electrode bonding pad 201 and the substrate bonding pad, the thicknesses of the flexible electrode bonding pad 201 and the substrate bonding pad are within 10um, and due to the adoption of the two metal bonding pads, compared with a conventional solder ball connection mode, the size of the bonding pad is greatly reduced, the bonding characteristic length in practice can be within 10 mu m, and the sealing feed-through density and the integration level are improved. The redistribution layer 3 is deposited on the back of the feed-through substrate 1, so that the feed-through substrate can adapt to the pin distribution of different ASIC chips, and the application range and application scene of integrated feed-through and flexible electrode devices are enlarged.
Another embodiment of the present invention provides a method for manufacturing a flexible electrode integrated with a feed-through substrate, referring to fig. 4, the method includes:
step 4, placing the feed-through substrate to enable the first surface to be located on the second surface, and spin-coating a flexible polymer on the first surface to form a flexible electrode substrate layer; patterning the flexible electrode base layer to expose the substrate bonding pad;
step 5, sputtering an electrode metal layer on the flexible electrode substrate layer; a photoresist mask is spin-coated on the electrode metal layer, and the electrode conducting layer is obtained through imaging after exposure and development; this step simultaneously forms a flexible electrode pad;
step 6, spin-coating a flexible polymer on the electrode conducting layer to form a flexible electrode packaging layer;
step 7, turning over the feed-through substrate to enable the second surface to be located on the first surface, and spin-coating a flexible polymer on the second surface to form a redistribution substrate layer;
step 8, according to the layout of the redistribution layer lead, sequentially carrying out patterning, metal layer sputtering and mask spin coating on the redistribution base layer, and patterning after exposure and development to form a redistribution lead layer; this step simultaneously forms the redistribution pad;
step 9, spin-coating a flexible polymer on the redistribution lead layer to form a redistribution packaging layer; and patterning the redistribution encapsulation layer to expose the redistribution pads.
In some embodiments, in step 1, a substrate having an array of microwells is formed, the substrate including any one of a ceramic substrate, a glass substrate, and a silicon-based substrate. The ceramic substrate can be prepared from ceramic powder and a mould with a micropillar array through a ceramic sintering process, the ceramic sintering method comprises sintering modes such as hot pressing sintering, hot isostatic pressing sintering, microwave sintering, plasma activated sintering and the like, a micropore array formed by a plurality of micropores is formed in the ceramic substrate through a sintering demoulding mode, the sintering demoulding mode has the capability of batch production, the process cost is low, the pore-forming appearance is good, and the stress distribution in the formed micropores is uniform. The glass substrate can be formed by cooling and solidifying a mold with a micro-column array by adopting molten glass instead of ceramic powder. The silicon-based substrate can form a silicon through hole array by using TSV technology under the conditions of etching masks and a Bosch process.
In some embodiments, the single layer thickness of the flexible electrode base layer and the flexible electrode encapsulation layer is 1-20 μm.
In some embodiments, a flexible polymer is spin-coated on the second surface to form a redistribution substrate layer, wherein: the redistribution layer is made of a flexible polymer doped with thermally conductive particles to improve thermal conductivity.
In some embodiments, the thickness of the single layer of the redistribution layer substrate layer and the redistribution layer encapsulation layer is 5-10 μm; the total thickness of the redistribution layer is 10-50 μm.
According to the preparation method of the flexible electrode, the ceramic feed-through substrate is sintered, the electrically interconnected conductive micro-column array is formed in the substrate, metal bonding pads are deposited on the surface and the back of the feed-through substrate with the electrically interconnected conductive micro-column array, and the bonding pads correspond to the substrate conductive micro-column array one by one. And spin coating a polymer substrate layer on the surface and the back of the feed-through substrate and patterning to expose the substrate micro-column holes. And depositing and patterning a metal layer on the surface and the back of the substrate. And spin-coating a polymer packaging layer on the surface and the back of the substrate and patterning to complete the construction of the flexible electrode and the redistribution layer. The redistribution layer can be further connected with an Application Specific Integrated Circuit (ASIC), and special diversified pin layout is met by matching a redistribution layer bonding pad with an ASIC chip pin, so that a device can be formed by adopting an integrated MEMS flow sheet mode, and the device is high in processing consistency and good in biocompatibility. And then sequentially completing the steps of metal pad deposition, flexible polymer film deposition, conducting layer deposition, flexible polymer packaging layer deposition and the like under the MEMS process to form a flexible electrode and a redistribution layer on the ceramic substrate.
In one embodiment, the method for manufacturing a flexible electrode of an integrated feed-through substrate includes the following steps:
1) Forming a ceramic substrate having a micro-pore array by a ceramic sintering process;
2) Electroplating conductive through holes in the micropore array and further flattening to form a ceramic feed-through substrate;
3) Depositing a biocompatible dielectric layer on the outer surface of the ceramic and metal pads on the top and back of the feedthrough;
4) Spin coating a biocompatible flexible polymer on the top of the feed-through substrate to form a flexible electrode substrate layer;
5) Patterning the flexible electrode substrate layer to expose the metal pad;
6) Sputtering a conductive layer on the flexible electrode substrate layer;
7) Spin-coating a photoresist mask on the conductive layer, and patterning the conductive metal layer after exposure and development;
8) Spin-coating a biocompatible flexible polymer on the top of the substrate to form a flexible electrode packaging layer;
9) Turning over the ceramic substrate, and spin-coating a flexible polymer doped with biocompatible particles such as AlN on the back of the ceramic substrate to form a redistribution base layer;
10 Carrying out steps 5) -7) on the back of the ceramic substrate according to the redistribution layer lead layout;
11 Spin coating a flexible polymer doped with particles such as AlN on the back of the substrate to form a redistribution encapsulation layer;
12 ) patterning the redistribution encapsulation layer to expose the redistribution pads.
In the integrated preparation method, the bonding encapsulation of the flexible electrode and the adapter plate (namely the electrical interconnection feed-through substrate) is completed under the MEMS process, so that the bonding process flow and the bonding difficulty are simplified, and the integrated tape-out process can realize high-controllability and high-repeatability processing.
Another embodiment of the present invention also provides an electrode device including an ASIC chip and the flexible electrode of the integrated feed-through substrate described above, and referring to fig. 3, the ASIC chip 4 is connected to redistribution pads, which enable signal communication between the flexible electrode and the ASIC chip 4 and redistribution of pins such as power supply pins and output pins of the ASIC chip 4. In this embodiment, no specific limitation is imposed on the ASIC chip, any chip meeting the functional requirements may be adopted, and the layout of the pad structure of the chip and the feed-through array in the feed-through substrate is correspondingly coordinated, so that signal communication can be realized.
The electrode device is connected with an Application Specific Integrated Circuit (ASIC) chip through the redistribution pad of the redistribution layer by any one of soldering, connection using an Anisotropic Conductive Film (ACF)), and connection using a conductive epoxy.
The flexible electrode of the integrated feed-through substrate of the present invention, its method of preparation and the electrode device are further described below by way of specific embodiments.
Example 1
In this embodiment, a method for integrally manufacturing a flexible electrode integrated with a feed-through substrate (integrated tape-out process) specifically includes the following steps, with reference to fig. 5:
as shown in S1 in figure 5, the fused mullite, the capacitance white corundum and the sintered alpha-Al are mixed 2 O 3 Micropowder, siO 2 Grinding and mixing the micro powder, adding a water-soluble resin binder, and pouring into a ceramic mold with a micro-column array.
As shown by S2 in fig. 5, after drying at 110 ℃ for 24 hours under 120MPa pressure, the mold and the ceramic powder were placed in a high temperature gas kiln at 1750 ℃ and hot pressed and sintered for 6 hours.
The ceramic formed by sintering is separated from the mold as shown by S3 in fig. 5, and a ceramic substrate having a micro-pore array is obtained.
And as shown in S4 in figure 5, a 10nm chromium barrier layer and a 30nm copper seed layer are sputtered at the micropores, and the micropore array is filled by adopting an electroplating copper process to form the conductive microcolumn array. As shown by S4 in fig. 5, the ceramic sintering process and the plating process cause unevenness of the entire ceramic substrate surface at the top and back of the ceramic substrate.
As shown in S5 in fig. 5, performing planarization treatment on the surface of the ceramic substrate by using chemical mechanical polishing to obtain a conductive feed-through structure which is connected up and down;
as shown in S6 of fig. 5, a layer of silicon carbide (SiC) of about 1 μm is deposited by plasma enhanced chemical vapor deposition, and a mask is previously applied around the micropillar holes before depositing the SiC, so as to prevent the SiC from blocking the silicon micropillar holes.
As shown at S7 in fig. 5, metal pads of 30nm chromium and 1 μm gold are sputter deposited at the openings of the SiC insulating layer, i.e., the micropillar holes.
As shown in S8 in fig. 5, a photosensitive polyimide Durimide 7505 (1000 rpm 7 seconds, 1500 rpm 30 seconds) was spin-coated on the SiC insulating layer, and exposed for 6 seconds, developed for 35 seconds, and cured at 350 ℃. Between the polyimide substrate layer (base layer) and the encapsulation layer, a 30nm thick chromium and 200nm thick gold conductive layer was sputter deposited. The polyimide layer and the conductive layer constitute a flexible electrode.
S9 in fig. 5 shows the process of turning the ceramic substrate upside down, and depositing the SiC insulating layer and depositing the metal pad on the turned-back surface, and the relevant parameters are consistent with the foregoing.
S10 in fig. 5 shows a process of constructing a redistribution layer on a ceramic substrate using the photosensitive polyimide Durimide 7505, which is likely to cause heat accumulation in consideration of connection of the redistribution layer with an ASIC chip. The polyimide polymer of the redistribution layer is doped with AlN particles to improve its thermal conductivity. The monolayer thickness of the polyimide polymer substrate layer and the encapsulation layer is 6 μm. The thickness of the conductive layer is 3 mu m, a single-layer wiring mode is adopted, and the thickness of the bonding pad at the opening welding point of the packaging layer is 1 mu m thick Au bonding pad. The total thickness of the redistribution layers was 16 μm.
Example 2
The present embodiment is different from the embodiment in that Parylene C (Parylene) is used as the flexible electrode substrate layer, and the specific steps of the preparation method are as follows:
s1: mixing electrically fused mullite, electric white corundum and sintered alpha-Al 2 O 3 Micropowder, siO 2 Grinding and mixing the micro powder, adding a water-soluble resin binder, and pouring into a ceramic mold with a micro-column array. Drying at 110 deg.C for 24 hr under 120MPa, and hot pressing and sintering at 1750 deg.C for 6 hr.
S2: and separating the sintered and formed ceramic from the mold to obtain the ceramic substrate with the micropore array. And sputtering a 10nm chromium barrier layer and a 30nm copper seed layer at the micropores, and filling the micropore array by adopting an electroplating copper process to form the conductive microcolumn array.
S3: and flattening the surface of the ceramic substrate by adopting chemical mechanical polishing to obtain an electrically interconnected feed-through structure which is communicated up and down.
S4: a layer of silicon carbide (SiC) with the thickness of about 1 μm is deposited by using a plasma enhanced chemical vapor deposition method, and a mask is coated in advance near the micro-column holes before the silicon carbide is deposited so as to prevent the SiC from blocking the silicon column holes.
S5: metal pads of 30nm chromium and 1 μm gold are sputter deposited at the openings of the SiC insulating layer, i.e. the micropillars.
S6: and depositing 5 mu m of Parylene C on the SiC insulating layer by adopting a chemical vapor deposition system (CVD) as a polymer substrate layer in the flexible electrode structure.
S7: and spin-coating 12-micron positive photoresist AZ4620 on the 5-micron Parylene C, and carrying out pre-baking, photoetching, developing and post-baking to obtain a patterned photoresist mask. And etching the Parylene C substrate layer with the photoresist mask by using an oxygen Plasma device to obtain a graphical Parylene C film.
S8: the ceramic substrate with Parylene C film was placed in an acetone solution and gently shaken to remove the photoresist AZ4620. The time for removing the photoresist is about 10min after the acetone is soaked.
S9: and sputtering and depositing a 30nm thick chromium and 200nm thick gold conducting layer on the Parylene C substrate layer, and using the positive photoresist as a patterning mask. The metal layer is patterned using ion beam etching and the remaining positive photoresist is removed using the same method.
S10: a5 μm thick layer of Parylene C top encapsulation was deposited using the same process as S6-S8. The substrate layer, the metal layer and the top packaging layer of the Parylene C form a flexible electrode.
S11: and (3) overturning the ceramic substrate, and depositing a SiC insulating layer and a metal bonding pad on the overturned surface, wherein relevant parameters are consistent with the parameters.
The process of constructing the redistribution layer on the ceramic substrate using the photosensitive polyimide Durimide 7505 easily causes heat accumulation in consideration of the connection of the redistribution layer with the ASIC chip. The polyimide polymer of the redistribution layer is doped with AlN particles to improve its thermal conductivity. The monolayer thickness of the polyimide polymer substrate layer and the encapsulation layer is 6 μm. The thickness of the conductive layer is 3 mu m, a single-layer wiring mode is adopted, and the thickness of the bonding pad at the opening welding point of the packaging layer is 1 mu m thick Au bonding pad. The total thickness of the redistribution layers was 16 μm.
The foregoing description of specific embodiments of the present invention has been presented. It is to be understood that the present invention is not limited to the specific embodiments described above, and that various changes and modifications may be made by one skilled in the art within the scope of the appended claims without departing from the spirit of the invention. The above-described preferred features may be used in any combination without conflict with each other.
Claims (10)
1. A flexible electrode integrated with a feed-through substrate, comprising, in order:
a flexible electrode having an electrode conductive layer;
the feed-through substrate is internally provided with a conductive micro-column array, the top surface and the bottom surface of the feed-through substrate are both provided with insulating layers, and the outer surface of each insulating layer is provided with a substrate bonding pad;
the redistribution layer is provided with a redistribution conductive layer and a redistribution bonding pad connected with the redistribution conductive layer, an external circuit is connected through the redistribution bonding pad, and the electrode conductive layer, the conductive micro-column array, the substrate bonding pad and the redistribution conductive layer are electrically connected.
2. The flexible electrode of an integrated feedthrough substrate of claim 1, wherein the feedthrough substrate comprises any of a ceramic feedthrough substrate, a glass feedthrough substrate, and a silicon-based feedthrough substrate.
3. The flexible electrode of integrated feed-through substrate of claim 1, wherein the electrode conductive layer has a thickness of 0.01-1 μ ι η.
4. The flexible electrode of an integrated feed-through substrate of claim 1, wherein the substrate pad has a thickness of 0.5-5 μm, and the insulating layer is made of any one of silicon dioxide, silicon carbide, aluminum oxide and zirconium oxide.
5. The flexible electrode of the integrated feed-through substrate of claim 1, wherein the redistribution conductive layer has a thickness of 1-10 μ ι η.
6. A method of making a flexible electrode of an integrated feed-through substrate of any of claims 1-5, comprising:
forming a substrate having an array of microwells;
filling a conductive material in the micropores of the micropore array, and flattening the surface of the substrate to form a feed-through substrate;
forming an insulating layer on a first surface of the feed-through substrate and a second surface opposite to the first surface, and forming a substrate pad on the insulating layer;
placing the feed-through substrate to enable the first surface to be located on the second surface, and spin-coating a flexible polymer on the first surface to form a flexible electrode base layer; patterning the flexible electrode base layer to expose the substrate bonding pad;
sputtering and forming an electrode metal layer on the flexible electrode substrate layer; a photoresist mask is spin-coated on the electrode metal layer, and an electrode conducting layer is obtained through imaging after exposure and development;
spin-coating a flexible polymer on the electrode conductive layer to form a flexible electrode packaging layer;
turning over the feed-through substrate to enable the second surface to be located on the first surface, and spin-coating a flexible polymer on the second surface to form a redistribution base layer;
according to the lead layout of the redistribution layer, sequentially patterning, sputtering a metal layer, spin-coating a mask on the redistribution base layer, exposing and developing, and then patterning to form a redistribution lead layer;
spin-coating a flexible polymer on the redistribution lead layer to form a redistribution packaging layer; and patterning the redistribution encapsulation layer to expose the redistribution pads.
7. The method of claim 6, wherein the base layer of the flexible electrode and the encapsulation layer of the flexible electrode have a monolayer thickness of 0.2-20 μm.
8. The method of claim 6, wherein the second surface is spin coated with a flexible polymer to form a redistribution substrate layer, wherein: the redistribution layer is made of a flexible polymer doped with thermally conductive particles to improve thermal conductivity.
9. The method of claim 6, wherein the redistribution layer substrate layer and the redistribution layer encapsulation layer have a monolayer thickness of 5-10 μ ι η; the total thickness of the redistribution layer is 10-50 μm.
10. An electrode device comprising an ASIC chip and a flexible electrode of the integrated feed-through substrate of any of claims 1 to 5, the ASIC chip being connected with the redistribution pad.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211394183.0A CN115662681A (en) | 2022-11-08 | 2022-11-08 | Flexible electrode integrated with feed-through substrate, preparation method of flexible electrode and electrode device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211394183.0A CN115662681A (en) | 2022-11-08 | 2022-11-08 | Flexible electrode integrated with feed-through substrate, preparation method of flexible electrode and electrode device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN115662681A true CN115662681A (en) | 2023-01-31 |
Family
ID=85015395
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202211394183.0A Pending CN115662681A (en) | 2022-11-08 | 2022-11-08 | Flexible electrode integrated with feed-through substrate, preparation method of flexible electrode and electrode device |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN115662681A (en) |
-
2022
- 2022-11-08 CN CN202211394183.0A patent/CN115662681A/en active Pending
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| TW584950B (en) | Chip packaging structure and process thereof | |
| US10052478B2 (en) | Implantable device for the brain | |
| TWI247373B (en) | Semiconductor package having semiconductor constructing body and method of manufacturing the same | |
| JP4854514B2 (en) | Method for integrating off-the-shelf chip structures into functional electronic systems | |
| TW517361B (en) | Chip package structure and its manufacture process | |
| TWI374531B (en) | Inter-connecting structure for semiconductor device package and method of the same | |
| TWI248655B (en) | Flip-chip type semiconductor device, production process for manufacturing such flip-chip type semiconductor device, and production process for manufacturing electronic product using such flip-chip type semiconductor device | |
| US20080046080A1 (en) | Method for forming packaged microelectronic devices and devices thus obtained | |
| US20110254171A1 (en) | Integrated Method for High-Density Interconnection of Electronic Components through Stretchable Interconnects | |
| US7804228B2 (en) | Composite passive materials for ultrasound transducers | |
| EP1107307A1 (en) | Semiconductor package, semiconductor device, electronic device, and method of manufacturing semiconductor package | |
| WO2018209872A1 (en) | Multi-layer, flexible artificial auditory nerve stimulation electrode and manufacturing method thereof | |
| TWI380500B (en) | Integrated circuit device having antenna conductors and the mothod for the same | |
| WO2010068515A2 (en) | Electronic devices including flexible electrical circuits and related methods | |
| CN1684256A (en) | Silicon chip carrier with conductive through-VIAS and method for fabricating same | |
| WO2006061058A1 (en) | Mems microphone and method for producing said microphone | |
| EP3551277B1 (en) | Implantable electrode and method for manufacturing | |
| TW201013889A (en) | Electronic component used for wiring and method for manufacturing the same | |
| TW200828553A (en) | A capacitance element embedded in semiconductor package substrate structure and method for fabricating TME same | |
| JP6307543B2 (en) | Non-planar integrated circuit device | |
| KR102403468B1 (en) | assembly platform | |
| CN115662681A (en) | Flexible electrode integrated with feed-through substrate, preparation method of flexible electrode and electrode device | |
| TW200913811A (en) | A circuit board structure with a capacitance element embedded therein and method for fabricating tme same | |
| WO2023240686A1 (en) | Flexible electrode apparatus for bonding with seeg electrode, and manufacturing method therefor | |
| JP5501745B2 (en) | Visual reproduction assist device |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |