阅读说明：本技术 一种具有电生理记录和多模态刺激功能的神经微电极阵列 (Neural microelectrode array with electrophysiological recording and multi-modal stimulation functions ) 是由 王明浩 樊晔 程瑜华 王高峰 于 2021-08-26 设计创作，主要内容包括：本发明公开了一种具有电生理记录和多模态刺激功能的神经微电极阵列。目前,由于受到集成技术和刺激伪迹的影响,大部分的多功能神经微电极阵列都不具有同时进行电生理记录、电刺激、光刺激和微流体刺激的功能。本发明采用ACF导电胶作为黏合层,通过热压键和实现微LED与多功能硅探针的光电集成。另一方面,为了避免记录通道中出现刺激伪迹,本发明在记录电极和刺激电极之间,硅探针与PI供电层之间均设置了金属屏蔽层,为实现微电极阵列同时进行高时空分辨率的刺激与记录提供技术和理论基础。同时,本发明在单个硅探针上同时集成了电记录、电刺激、光刺激和微流体刺激功能,大大提高了神经微电极阵列的多功能性。(The invention discloses a neural microelectrode array with electrophysiological recording and multi-modal stimulation functions. At present, most of multifunctional neural microelectrode arrays do not have the functions of simultaneously performing electrophysiological recording, electrical stimulation, optical stimulation and microfluidic stimulation due to the influence of integration technology and stimulation artifacts. The invention adopts ACF conductive adhesive as an adhesive layer, and realizes the photoelectric integration of the micro LED and the multifunctional silicon probe through hot pressing. On the other hand, in order to avoid stimulation artifacts in the recording channel, metal shielding layers are arranged between the recording electrode and the stimulation electrode and between the silicon probe and the PI power supply layer, so that a technical and theoretical basis is provided for realizing stimulation and recording of the microelectrode array with high space-time resolution simultaneously. Meanwhile, the invention integrates the functions of electric recording, electric stimulation, optical stimulation and microfluid stimulation on a single silicon probe, thereby greatly improving the versatility of the neural microelectrode array.)

1. A neural microelectrode array with electrophysiological recording and multi-modal stimulation functions comprises a silicon probe (1) and a PI power supply layer (3); the method is characterized in that: a recording electrode point (9), a stimulating electrode point (11), a micro LED (4) and a micro fluid channel (13) are integrated on the silicon probe (1) to respectively realize electric recording, electric stimulation, optical stimulation and micro fluid drug delivery; the recording electrode point and the stimulating electrode point are isolated by a grounded metal layer and a metal lead; the micro LED and the micro fluid channel are embedded in the silicon probe; the micro LED is aligned through a positioning groove on the silicon probe (1) and is bonded with a micro LED bonding pad on the PI power supply layer (3) by ACF hot pressing.

2. The neural microelectrode array with the electrophysiological recording and multi-modal stimulation functions of claim 1, wherein: the silicon probe (1) and the PI power supply layer (3) are bonded together through an ACF bonding layer (2) in a hot pressing mode; metal pads (6) are also distributed on the silicon probe (1); the metal pad (6) is electrically connected with the PI flat cable (8); power supply pads (7) are also distributed on the PI power supply layer (3); the recording electrode point (9) and the stimulating electrode point (11) are respectively connected with the corresponding metal bonding pad (6) through metal leads.

3. The neural microelectrode array with the electrophysiological recording and multi-modal stimulation functions of claim 1, wherein: four annular grounding electrode points (10) are uniformly distributed around the stimulating electrode point (11); the stimulating electrode point (11) and its conductor are separated from the recording electrode point (9) and its conductor by a metal shielding layer and an annular grounding electrode point (10) and its conductor.

4. The neural microelectrode array with the electrophysiological recording and multi-modal stimulation functions of claim 1, wherein: the length of the silicon probe (1) is 5-100 mm, the width is 100-1000 microns, and the thickness is 20-200 microns; the diameter of the recording electrode point (9) is 10-50 microns, and the diameter of the stimulating electrode point (11) and the grounding electrode point (10) is 10-100 microns.

5. The neural microelectrode array with the electrophysiological recording and multi-modal stimulation functions of claim 1, wherein: the micro-LEDs are completely embedded in the positioning grooves on the silicon probes.

6. The neural microelectrode array with electrophysiological recording and multi-modal stimulation functions of claim 1, wherein: the preparation method comprises the following steps:

preparing and integrating a PI power supply layer and an ACF bonding layer in a neural microelectrode array;

step two, preparing and integrating a silicon probe in the neural microelectrode array;

and step three, integrating micro LEDs in the neural microelectrode array.

7. The neural microelectrode array with the electrophysiological recording and multi-modal stimulation functions of claim 1, wherein: the specific process of the first preparation method step is as follows:

(1) forming a sacrificial layer on a quartz glass sheet; the sacrificial layer is obtained by depositing aluminum or by spin coating PMMA;

(2) spinning a polyimide solution on the sacrificial layer and heating and curing;

(3) depositing a metal layer on the polyimide film obtained in the step (2); subsequently, patterning the metal layer into a micro LED pad and a power supply pad using the photoresist as a mask;

(4) attaching a layer of ACF conductive adhesive on the micro LED bonding pad and hot-pressing;

(5) preparing a layer of silicon oxide on the surface of a single-side polished silicon wafer by adopting a thermal oxidation method to serve as an insulating layer;

(6) sputtering and depositing a metal layer on the insulating layer obtained in the step (5) to be used as an electromagnetic shielding layer;

(7) depositing a layer of silicon oxide on the electromagnetic shielding layer obtained in the step (6) to be used as an insulating layer;

(8) attaching one side of the silicon wafer with the silicon oxide to the PI power supply layer formed in the steps (1) - (7) and carrying out hot-press bonding; the silicon wafer was then thinned to a thickness of 50-200 microns.

8. The neural microelectrode array with the electrophysiological recording and multi-modal stimulation functions of claim 7, wherein: the preparation method comprises the following specific steps:

(1) depositing a silicon oxide insulating layer on a silicon wafer bonded with the PI power supply layer;

(2) patterning the silicon oxide insulating layer obtained in the step (1) into a hard mask of a microfluidic channel, then forming a channel structure by using deep silicon etching, and finally adopting PECVD (plasma enhanced chemical vapor deposition) conformal deposition to deposit a layer of silicon oxide to close an upper opening of the channel structure;

(3) depositing a chromium/gold film on the silicon oxide by using a magnetron sputtering system; then, using the photoresist as a mask, and patterning the chromium/gold film into a stimulation electrode point, a lead and a bonding pad by using a wet etching technology to form a stimulation electrode layer;

(4) depositing a layer of silicon oxide on the stimulating electrode layer as an insulating layer, and depositing a layer of chromium/gold film on the insulating layer; then, using the photoresist as a mask, and patterning the chromium/gold thin film into an electromagnetic shielding layer by using a wet etching technology;

(5) depositing a layer of silicon oxide on the electromagnetic shielding layer to serve as an insulating layer; depositing a chromium/gold film on the insulating layer; then, using photoresist as a mask, and patterning the chromium/gold thin film into a recording electrode point, a wire and a bonding pad by using an ion beam etching technology; finally, depositing a layer of silicon oxide as the insulating layer of the recording electrode;

(6) the stimulating electrode points, recording electrode points, pads and contours are exposed using RIE techniques using the photoresist as a mask.

9. The neural microelectrode array with the electrophysiological recording and multi-modal stimulation functions of claim 8, wherein: the preparation method comprises the following specific processes:

(1) etching silicon, silicon oxide, chromium/gold and silicon oxide by using DRIE, RIE, wet etching and RIE respectively by using the patterned photoresist as a mask to expose the ACF on the micro LED bonding pad;

(2) bonding the micro LED and the micro LED bonding pad together by using a hot press to realize electrical conduction and mechanical adhesion;

(3) depositing a parylene C layer or spin-coating a PI layer to be used as an electric insulation layer of the micro LED; subsequently, the electrically insulating layer is patterned by RIE using the patterned photoresist as a mask to expose the recording electrode points and the stimulating electrode points and the pads; dissolving the sacrificial layer and releasing the glass sheet substrate; and then, depositing a parylene C layer on the surface of the PI power supply layer or spin-coating a PI layer to be used as an electric insulation layer of the PI power supply layer.

Technical Field

The invention belongs to the technical field of MEMS biosensors, and particularly relates to a preparation and integration method of a multifunctional neural microelectrode array for electrophysiological recording and multi-modal stimulation.

Background

Currently, mortality is high as 12% worldwide due to neurological diseases, including epilepsy, parkinsonism tremor, and multiple sclerosis. Nowadays, one can confirm the location of a lesion by recording the local field potential of an epileptic patient and prevent epileptic seizures by surgically resecting or electrically stimulating the lesion. In addition, tremors caused by advanced parkinson's disease can also be alleviated by deep brain electrical stimulation of the hypothalamus and globus pallidus. Therefore, diagnosis, treatment and intervention of major brain diseases become one of three major pillars with practical significance and future value in brain plans in China. Stimulating and recording neural activity with high spatial and temporal resolution is important to understand how neurons communicate with each other and how behavioural functions are abnormal.

In order to realize the stimulation and recording functions of the neural microelectrode array, a method which is usually adopted at present is to integrate a recording electrode with an optical fiber, an optical waveguide and an LD/LED. Doctor f.wu, university of michigan, coupled a silicon oxynitride optical waveguide integrated on a michigan electrode with An optical fiber in the paper "An implantable neural probe with monolithic integrated direct waveguide and recording electronics for optical networking applications" achieved 8-channel recording and 1-channel optical stimulation. However, this method causes the optical fiber to be wound and thus restricts the free movement of the behavioral animal. To avoid the use of optical fibers, the professor p.ruther, freiburg university, germany, in the paper "Compact Silicon-based optical with Integrated Laser Diode Chips, SU-8Waveguides and Platinum Electrodes for optical Applications" coupled with a polymer SU-8 optical waveguide using a bare Laser Diode (LD) achieves 8-channel recording and 4-channel optical stimulation. Professor e.yoon at the university of michigan further couples a plurality of LDs with different wavelengths with silicon oxynitride optical waveguides in the paper "Dual color optical control of neural networks using low-noise, multishank optical waveguides", thereby realizing 32-channel recording and 4-channel optical stimulation/suppression functions. To improve photostimulation Resolution, professor e.yoon, michigan university, usa, in the paper "monolithic Integrated mu LEDs on Silicon Neural Probes for High-Resolution optical Studies in Behaving Animals" further Monolithically integrates 12 micro-LEDs and 32 recording electrode dots on 4 Silicon-based microprobes, the spatial Resolution of the LEDs and electrode dots of which can be less than 1 micron. The multifunctional neural microelectrode prepared by the method can realize the functions of light stimulation and electrophysiological recording at the same time. By analyzing the current research situation of the multifunctional neural microelectrode, most of the existing multifunctional neural microelectrode arrays do not have the functions of simultaneously performing electrophysiological recording, electrical stimulation, optical stimulation and microfluid stimulation. This is due to the poor compatibility of the current fabrication process of most neuro-microelectrodes with the fabrication process of micro-LEDs or microfluidic channels. On the other hand, the multifunctional integration of neural microelectrodes is also limited by stimulation artifacts introduced in the recording channel during electrical, optical and microfluidic stimulation.

Disclosure of Invention

Aiming at the defects in the prior art, the invention aims to realize the preparation and integration of a novel multifunctional neural microelectrode array with electrophysiological recording, optical stimulation, electrical stimulation and fluid administration functions by utilizing an MEMS micro-processing technology.

A neural microelectrode array with electrophysiological recording and multi-modal stimulation functions comprises a silicon probe and a PI power supply layer; the silicon probe is integrated with a recording electrode point, a stimulating electrode point, a micro LED and a microfluid channel, and respectively realizes electric recording, electric stimulation, optical stimulation and microfluid administration. The recording electrode point and the stimulating electrode point are separated by a grounded metal layer and a metal lead. Both the micro-LEDs and the microfluidic channels are embedded within silicon probes. The micro LED is aligned through a positioning groove on the silicon probe and is bonded with a micro LED bonding pad on the PI power supply layer by ACF hot pressing.

Preferably, the silicon probe and the PI power supply layer are bonded together through an ACF bonding layer in a hot pressing mode; metal pads are also distributed on the silicon probe. The metal pad is electrically connected with the PI bus. And power supply pads are also distributed on the PI power supply layer. The recording electrode points and the stimulating electrode points are respectively connected with the corresponding metal bonding pads through metal leads.

Preferably, four annular grounding electrode points are uniformly distributed around the stimulating electrode point; the stimulating electrode points and the leads thereof are isolated from the recording electrode points and the leads thereof by the metal shielding layer and the annular grounding electrode points and the leads thereof.

Preferably, the length of the silicon probe is 5-100 mm, the width is 100-1000 microns, and the thickness is 20-200 microns; the diameter of the recording electrode point is 10-50 microns, and the diameter of the stimulating electrode point and the grounding electrode point is 10-100 microns.

Preferably, the recording electrode points, stimulating electrode points, micro-LEDs and microfluidic channels perform electrophysiological recording, electrical stimulation, optical stimulation and fluid stimulation synchronously or asynchronously.

Preferably, the micro-LEDs are completely embedded in the positioning grooves on the silicon probe.

The preparation method of the neural microelectrode array with the electrophysiological recording and multi-modal stimulation functions comprises the following steps:

step one, preparing and integrating a PI power supply layer and an ACF bonding layer in the neural microelectrode array.

And step two, preparing and integrating the silicon probe in the neural microelectrode array.

And step three, integrating micro LEDs in the neural microelectrode array.

Preferably, the specific process of the first preparation method step is as follows:

(1) a sacrificial layer is formed on a quartz glass wafer. The sacrificial layer is obtained by depositing aluminum or by spin-coating PMMA.

(2) And spin-coating a polyimide solution on the sacrificial layer and heating for curing.

(3) And (3) depositing a metal layer on the polyimide film obtained in the step (2). The metal layer is then patterned into micro LED pads and power supply pads using the photoresist as a mask.

(4) And attaching a layer of ACF conductive adhesive on the micro LED bonding pad and hot-pressing.

(5) And preparing a layer of silicon oxide on the surface of the single-side polished silicon wafer by adopting a thermal oxidation method to serve as an insulating layer.

(6) And (5) sputtering and depositing a metal layer on the insulating layer obtained in the step (5) to be used as an electromagnetic shielding layer.

(7) And (4) depositing a layer of silicon oxide as an insulating layer on the electromagnetic shielding layer obtained in the step (6).

(8) And (3) attaching the side of the silicon wafer with the silicon oxide to the PI power supply layer formed in the steps (1) to (7) and carrying out thermocompression bonding. The silicon wafer was then thinned to a thickness of 50-200 microns.

Preferably, the specific process of the second preparation method is as follows:

(1) and depositing a silicon oxide insulating layer on the silicon wafer bonded with the PI power supply layer.

(2) And (2) patterning the silicon oxide insulating layer obtained in the step (1) into a hard mask of a microfluidic channel, then forming a channel structure by using deep silicon etching, and finally conformally depositing a layer of silicon oxide by adopting PECVD (plasma enhanced chemical vapor deposition) to close an upper opening of the channel structure.

(3) A chromium/gold film is deposited on the silicon oxide using a magnetron sputtering system. Subsequently, the chrome/gold thin film is patterned into a stimulation electrode point, a wire, and a pad using the photoresist as a mask using a wet etching technique to form a stimulation electrode layer.

(4) Depositing a layer of silicon oxide as an insulating layer on the stimulating electrode layer, and depositing a chromium/gold film on the insulating layer. Subsequently, the chrome/gold thin film was patterned into an electromagnetic shield layer using a wet etching technique using the photoresist as a mask.

(5) And depositing a layer of silicon oxide as an insulating layer on the electromagnetic shielding layer. A chromium/gold film is then deposited on the insulating layer. Next, the chromium/gold thin film was patterned into recording electrode points, wires, and pads using the photoresist as a mask using an ion beam etching technique. Finally, a layer of silicon oxide is deposited again as an insulating layer of the recording electrode.

(6) The stimulating electrode points, recording electrode points, pads and contours are exposed using RIE techniques using the photoresist as a mask.

Preferably, the specific process of the third step of the preparation method is as follows:

(1) using the patterned photoresist as a mask, silicon oxide, chrome/gold and silicon oxide were etched away using DRIE, RIE, wet etch and RIE, respectively, exposing the ACF on the micro LED pads.

(2) And bonding the micro LED and the micro LED bonding pad together by using a hot press to realize electrical conduction and mechanical adhesion.

(3) A parylene C layer is deposited or a PI layer is spin-coated as an electrical insulation layer of the micro LED. Subsequently, the electrically insulating layer was patterned by RIE using the patterned photoresist as a mask to expose the recording electrode dots and stimulating electrode dots and the pads.

(4) The sacrificial layer is dissolved, releasing the glass sheet substrate. And then, depositing a parylene C layer on the surface of the PI power supply layer or spin-coating a PI layer to be used as an electric insulation layer of the PI power supply layer.

The invention has the beneficial effects that:

1. the invention adopts ACF conductive adhesive as the bonding layer, realizes the electrical connection and mechanical bonding of the micro LED and the multifunctional silicon probe by one step through a hot-pressing bonding process, and greatly improves the photoelectric integration efficiency of the multifunctional silicon probe.

2. The micro LED and the micro fluid channel are embedded in the silicon probe, so that the increase of the sectional area of the silicon probe is avoided, and the implantation damage is reduced.

3. When the metal wires are arranged, the wires connected with the stimulating electrode points and the wires connected with the recording electrode points are isolated by the wires connected with the grounding electrode points, so that mutual interference between an externally input stimulating signal and an acquired recording signal is further avoided, and the independence and the stability of a plurality of different functions of the multifunctional electric-stimulation-type medical-recording-type medical-electric-stimulation device are improved.

4. The invention integrates the functions of electric recording, electric stimulation, optical stimulation and microfluid stimulation on a single silicon probe, thereby greatly improving the versatility of the neural microelectrode array.

Drawings

FIG. 1 is an exploded view of the overall structure of the present invention;

FIG. 2 is a schematic front view of a silicon probe according to the present invention;

FIG. 3 is a flow chart of the process for preparing and integrating the PI power supply layer and the ACF adhesive layer according to the present invention;

FIG. 4 is a flow chart of a process for fabricating and integrating a silicon probe according to the present invention;

FIG. 5 is a flow chart of a specific integration process of the micro LED of the present invention;

Detailed Description

The invention is further described below with reference to the accompanying drawings.

As shown in figure 1, a neural microelectrode array with electrophysiological recording and multi-modal stimulation functions comprises a silicon probe 1, an ACF bonding layer 2, a PI power supply layer 3, a micro LED4 and a PI bus 8. The silicon probe 1 and the PI power supply layer 3 are thermally press-bonded together by the ACF adhesion layer 2. The metal pad 6 and the PI bus bar 8 are electrically connected through ACF conductive adhesive. The PI power supply layer 3 is distributed with micro LED pads 5 and power supply pads 7.

As shown in fig. 2, the silicon probe 1 is distributed with a recording electrode point 9, an annular grounding electrode point 10, a stimulating electrode point 11, a positioning groove 12 and a microfluidic channel 13. The microfluidic channel 13 is located on one side of the silicon probe 1. The recording electrode point 9, the annular grounding electrode point 10 and the stimulating electrode point 11 are respectively connected with the corresponding metal pad 6 through metal leads. The micro LEDs 4 are positioned by the positioning grooves 12 and electrically connected and mechanically bonded with the micro LED pads on the PI power supply layer 3 by ACF conductive glue. A stimulation electrode point 11 and a plurality of annular grounding electrode points 10 surrounding the stimulation electrode point 11 form an electrical stimulation unit. The plurality of electrostimulation units and the plurality of positioning grooves 12 are arranged in turn and alternately. The plurality of groups of recording electrode points 9 and the plurality of electrical stimulation units are respectively arranged in parallel. Electromagnetic shielding layers are arranged between the silicon probe 1 and the PI power supply layer 3 and between the recording electrode point 9 and the electrical stimulation unit. The lead connecting the stimulating electrode point 11 is isolated from the lead connecting the recording electrode point 9 by the lead connecting the ground electrode point 10. The length of the silicon probe 1 is 5-100 mm, the width is 100-1000 microns, and the thickness is 20-200 microns; the diameter of the recording electrode point 9 is 10-50 microns, and the diameter of the stimulating electrode point 11 and the grounding electrode point 10 is 10-100 microns.

Example 1

The specific preparation steps of the high multifunctional neural microelectrode array are as follows:

step 1, as shown in fig. 3, the preparation and integration of the PI power supply layer and the ACF adhesion layer in the neural microelectrode array specifically comprises the following steps:

(1) an electron beam evaporation system was used to deposit a layer of 300 nm thick aluminum as a sacrificial layer on the quartz glass wafer.

(2) Spin coating polyimide solution with thickness of 5 microns on the sacrificial layer of aluminum, standing for 5 minutes, and then performing pre-baking at 80 ℃ for 10 minutes, 120 ℃ for 30 minutes, 150 ℃ for 10 minutes, 180 ℃ for 10 minutes, and 220 ℃ for 40 minutes. This process forms the first insulating layer of the PI power supply layer.

(3) A chromium/gold film was deposited on the polyimide film (first insulating layer) using a magnetron sputtering system to a thickness of 20/200 nm each. Subsequently, the chrome/gold thin film was patterned into micro LED pads and power supply pads using a wet etching technique using the photoresist as a mask.

(4) And attaching a layer of ACF conductive adhesive on the micro LED bonding pad, and preliminarily fixing the ACF conductive adhesive by using a hot press. The working pressure of the hot press is 0.1Mpa, the temperature is 140 ℃, and the time is 5 seconds.

(5) Preparing a layer of silicon oxide with the thickness of 500 nanometers on the surface of a single-side polished silicon wafer by adopting a thermal oxidation method to serve as an insulating layer.

(6) A chromium/gold thin film with a thickness of 20/200 nm respectively is sputtered and deposited on the silicon oxide (the insulating layer obtained in step 5) to serve as an electromagnetic shielding layer.

(7) And depositing a layer of silicon oxide with the thickness of 500 nanometers on the chromium/gold thin film (the electromagnetic shielding layer) by adopting a PECVD system to be used as a second insulating layer of the PI power supply layer.

(8) And attaching the surface of the silicon wafer with the silicon oxide to the PI power supply layer on the glass sheet, and bonding the silicon wafer and the glass sheet together by using a hot press, wherein the working pressure of the hot press is 0.2Mpa, the temperature is 240 ℃, and the time is 15 seconds. Subsequently, the thickness of the silicon wafer was reduced to 200 μm using a lapping machine.

Step 2, preparing and integrating a silicon probe in the neural microelectrode array, wherein the specific process is as follows:

(1) and depositing a silicon oxide insulating layer with the thickness of 500 nanometers on the thinned silicon surface by using a PECVD system.

(2) The silicon oxide was patterned into a 2 micron wide channel structure using photolithography and Reactive Ion Etching (RIE). Subsequently, an isotropic deep silicon etch (DRIE) was used to form the tubular channel structure, and a layer of 1 micron thick silicon oxide was conformally deposited by PECVD to close the upper opening of the tubular channel structure.

(3) A layer of chromium/gold film was deposited on the silicon oxide using a magnetron sputtering system, each having a thickness of 20/200 nm. Subsequently, the metal film is patterned into a stimulation electrode point, a wire and a pad using a wet etching technique using the photoresist as a mask, forming a stimulation electrode layer.

(4) And depositing a layer of silicon oxide with the thickness of 500 nanometers on the stimulating electrode layer by adopting a PECVD system as an insulating layer, and depositing a layer of chromium/gold film with the thickness of 20/200 nanometers on the silicon oxide by using a magnetron sputtering system again. Subsequently, the metal thin film is patterned into the electromagnetic shielding layer using the photoresist as a mask using a wet etching technique.

(5) And depositing a layer of silicon oxide with the thickness of 500 nanometers on the electromagnetic shielding layer by adopting a PECVD system to be used as an insulating layer. Subsequently, an 20/200 nm thick chromium/gold film was deposited on the silicon oxide using a magnetron sputtering system. Next, the metal thin film is patterned into recording electrode points, wires, and pads using the photoresist as a mask using an ion beam etching technique. Finally, a layer of 500 nm thick silicon oxide was deposited again using the PECVD system as the insulating layer for the recording electrode.

(6) The silicon oxide is patterned using RIE techniques using the photoresist as a mask to expose the stimulating and recording electrode points, pads and contours.

Step 3, integrating micro LEDs in the neural microelectrode array, wherein the specific process is as follows:

(1) using the patterned photoresist as a mask, silicon oxide, chrome/gold and silicon oxide were etched away using DRIE, RIE, wet etch and RIE, respectively, exposing the ACF on the micro LED pads.

(2) And placing the micro LED into a positioning groove on a silicon wafer by using a chip mounter, and bonding the micro LED and a bonding pad below the micro LED together by using a hot press, wherein the working pressure of the hot press is 0.2Mpa, the temperature is 240 ℃, and the time is 15 seconds. The step realizes the electrical conduction and mechanical bonding of the micro LED and the silicon probe.

(3) A 5 micron thick layer of parylene C was conformally deposited on the side to which the micro-LEDs were bonded using a chemical vapor deposition system (CVD) as an electrical insulating layer for the micro-LEDs. Subsequently, parylene C was patterned by RIE using the patterned photoresist as a mask to expose the recording and stimulating electrode points and the pad.

(4) The sacrificial layer of aluminum is dissolved in dilute hydrochloric acid solution to release the glass slide substrate. Subsequently, a 5 μm thick parylene C was conformally deposited on the surface of the PI feeding layer using CVD as an electrically insulating layer of the PI feeding layer.

Example 2

Step 1, preparing and integrating a PI power supply layer and an ACF bonding layer in a neural microelectrode array, wherein the specific process comprises the following steps:

(1) PMMA was spin coated on a quartz glass plate and cured by heating under 110 ° for 5 minutes, 150 ° for 5 minutes, and 180 ° for 10 minutes. The process forms a sacrificial layer of the PI power supply layer.

(2) A polyimide solution with the thickness of 5 microns is coated on PMMA in a spinning mode, standing is carried out for 5 minutes, and then pre-drying is carried out, wherein the pre-drying temperature is 80 ℃ for 10 minutes, 120 ℃ for 30 minutes, 150 ℃ for 10 minutes, 180 ℃ for 10 minutes, and 220 ℃ for 40 minutes. This process forms the first insulating layer of the PI power supply layer.

(3) A copper film was deposited on the polyimide film using a magnetron sputtering system to a thickness of 200 nm. Subsequently, the metal thin film is patterned into the micro LED pad and the power supply pad using a wet etching technique using the photoresist as a mask.

(4) And attaching a layer of ACF conductive adhesive on the micro LED bonding pad, and preliminarily fixing the ACF conductive adhesive by using a hot press. The working pressure of the hot press is 0.1Mpa, the temperature is 140 ℃, and the time is 5 seconds.

(5) And preparing a layer of silicon oxide with the thickness of 500 nanometers on the surface of the single-side polished silicon wafer by adopting a PECVD system to serve as an insulating layer.

(6) A copper film with the thickness of 200 nanometers is sputtered and deposited on the silicon oxide to be used as an electromagnetic shielding layer.

(7) And depositing a layer of silicon oxide with the thickness of 500 nanometers on the copper film by adopting a PECVD system to be used as a second insulating layer of the PI power supply layer.

(8) And attaching the surface of the silicon wafer with the silicon oxide to the PI power supply layer on the glass sheet, and bonding the silicon wafer and the glass sheet together by using a hot press, wherein the working pressure of the hot press is 0.2Mpa, the temperature is 240 ℃, and the time is 15 seconds. The silicon wafer was then thinned to a thickness of 200 microns using a lapping machine.

And 2, preparing and integrating the silicon probe in the neural microelectrode array, wherein the specific process is the same as that of the example 1.

Step 3, integrating micro LEDs in the neural microelectrode array, wherein the specific process is as follows:

(1) using the patterned photoresist as a mask, silicon oxide, chrome/gold and silicon oxide were etched away using DRIE, RIE, wet etch and RIE, respectively, exposing the ACF on the micro LED pads.

(2) And placing the micro LED into a positioning groove on a silicon wafer by using a chip mounter, and bonding the micro LED and a micro LED bonding pad below the micro LED together by using a hot press, wherein the working pressure of the hot press is 0.2Mpa, the temperature is 240 ℃, and the time is 15 seconds. The step realizes the electrical conduction and mechanical bonding of the micro LED and the silicon probe.

(3) And spin-coating a layer of PI with the thickness of 5 microns on one surface bonded with the micro LED to be used as an electric insulating layer of the micro LED. Subsequently, PI was patterned by RIE using the patterned photoresist as a mask to expose the recording electrode points and the stimulating electrode points and the pads.

(4) The PMMA layer was dissolved away in acetone solution, releasing the glass slide substrate. Subsequently, a 5 μm thick PI layer was spin-coated on the surface of the PI power supply layer as an electrical insulation layer of the PI power supply layer.