KR101616294B1 - Hybrid type microelectrode array and fabrication method thereof - Google Patents

Abstract

TECHNICAL FIELD The present invention relates to a hybrid type microelectrode array having both types of electrodes of an invasive type and a non-invasive type, and a method of manufacturing the hybrid type microelectrode array. The present invention provides a microelectronic device comprising at least one infiltrating type microelectrode; At least one non-invasive microelectrode; And an insulative support for supporting the invasive microelectrode and the non-invasive microelectrode and electrically insulating the invasive microelectrode and the non-invasive microelectrode.

Description

HYBRID TYPE MICROELECTRODE ARRAY AND FABRICATION METHOD THEREOF BACKGROUND OF THE INVENTION 1. Field of the Invention [0001]

The present invention relates to a microelectrode array and a method of manufacturing the same, and more particularly, to a hybrid type microelectrode array having both types of electrodes of an invasive type and a noninvasive type, and a method of manufacturing the same.

 Conventional electrodes implanted into the human body, such as the brain and nerves, are largely divided into an invasive type and a noninvasive type, which are classified according to the presence or absence of the invasion of the electrode to the biotissue at the site where the electrode is implanted. Generally, the infiltrative electrode is in the form of a needle, a metal electrode is disposed at an end thereof, and a metal pad is patterned on a non-invasive, flat, polymer-based support. In the case of an invasive electrode, the influence or the range of interest is very narrow because it is intended to penetrate a living tissue and apply electrical stimulation to a single nerve cell or extract a signal. In contrast, non-invasive electrodes do not target a single nerve cell, but have an effect or interest on the surface on which the electrode is located and the nerve cells around it.

The use of noninvasive electrodes is convenient to use for research or therapeutic purposes by grouping or zoning many neurons, but it is difficult to access single neurons that have unique functions. In addition, the use of an invasive electrode facilitates access to the target neuron due to its shape, but it is difficult to influence the surrounding area or to obtain a signal.

Therefore, in order to understand the electrical interaction between a group of nerve cells and a single nerve cell, an electrode array having both the advantages of the two types of electrodes, invasive and non-invasive, is required.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems of the prior art, and it is an object of the present invention to provide a hybrid type microelectrode array having both types of electrodes of an invasive type and a noninvasive type, and a method of manufacturing the hybrid type microelectrode array.

In order to solve the above problems, the present invention provides a microelectronic device comprising: at least one infiltrating type microelectrode; At least one non-invasive microelectrode; And an insulative support for supporting the invasive microelectrode and the non-invasive microelectrode and electrically insulating the invasive microelectrode and the non-invasive microelectrode.

It is preferable that a second metal layer is formed at one end of the invasive microelectrode and at one end of the non-invasive microelectrode.

In addition, it is preferable that a first metal layer is formed at the other end of the invasive microelectrode and at the other end of the non-invasive microelectrode.

Further, it is preferable that at least a part of the surfaces of the invasive microelectrode and the non-invasive microelectrode on which the first metal layer and the second metal layer are not formed are formed with an electrical and chemical protective film as an insulating material.

In addition, it is preferable that the insulating support is made of polydimethylsiloxane.

The present invention also provides a method of manufacturing a semiconductor device, comprising: (a) preparing a silicon wafer; (b) forming a groove having a predetermined pattern on one surface of the silicon wafer; (c) bonding a first insulator to the one surface of the silicon wafer; (d) injecting and curing a second insulator into the space between the groove and the first insulator; (e) removing the first insulator; And (f) forming an invasive microelectrode and a non-invasive microelectrode electrically insulated from each other by the second insulator on the other surface of the silicon wafer.

The first insulator and the second insulator are preferably polydimethylsiloxane.

The grooves may include at least one first groove formed in a straight line on one surface of the silicon wafer; And at least one second groove formed in a straight line perpendicular to the first groove, and is formed in a lattice pattern.

The grooves can be machined or formed by depth reactive ion etching (DRIE).

The step (c) includes the steps of: (c1) subjecting the groove to a hydrophilic surface treatment; (c2) subjecting a surface of the first insulator bonded to one surface of the silicon wafer to a hydrophobic surface treatment; And (c3) bonding one surface of the silicon wafer and one surface of the first insulator.

The step (d) may include: (d1) injecting the second insulator into a space between the groove and the first insulator in the vacuum chamber.

The step (f) may further include: (f1) forming a silicon pillar on the other surface of the silicon wafer; (f2) removing the silicon pillar located at a portion where the non-invasive microelectrode is to be formed; (f3) removing the bottom of the trench between the silicon pillars until the insulating support is exposed; And (f4) sharpening the ends of the silicon pillars.

The step (a) may include a step of laminating a first metal layer on one surface of the silicon wafer.

The method of fabricating the hybrid type microelectrode array may further include the step of (g) forming a second metal layer on the tip of the invasive microelectrode and a part of the top surface of the non-invasive microelectrode after the step (f) .

The hybrid type microelectrode array fabricating method may further include, after the step (g), (h) the steps of: (h) forming the first and second metal layers and the non- And forming an electrical and a chemical protective film with an insulating material on the remaining portion of the substrate.

According to one embodiment of the present invention, since both electrodes of the two types, that is, the invasive type and the non-invasive type, are provided in one electrode array, access to the target neuron is easy, And it is easy to understand the electrical interaction between a group of nerve cells and a single nerve cell.

According to one embodiment of the present invention, since both electrodes of the two types, that is, an invasive type and a non-invasive type, are provided in one electrode array, a single nerve cell or a minimum- And at the same time, a reaction signal of the peripheral region such as ECoG is confirmed through the pad-type electrode, or, conversely, electrical stimulation is applied to a specific region of the body such as the brain or nerve through the pad- It is possible to identify the response signal of the target single nerve cell or the minimal nerve cell group through the invasive electrode.

The electrode arrangement according to an embodiment of the present invention is a multi-channel electrode having both types of electrodes of an invasive type and a non-invasive type in an electrode arrangement, It is possible to apply electrical stimulation or to extract a signal.

In addition, in the case of the non-invasive electrode, a device capable of fixing the position is separately required for attaching to the body. However, according to an embodiment of the present invention, the insulative support of the electrode arrangement is made of a flexible material, Since it acts like an anchor, it can be stably fixed to various parts of a curved body as well as a flat body part, and there is an advantage that a fixing device is not required when fixing to a body part.

1 is a perspective view of a hybrid type microelectrode array according to an embodiment of the present invention.
2 is a cross-sectional view taken along the line A-A 'in Fig.
3 is a flowchart illustrating a method of manufacturing a hybrid type microelectrode array according to an embodiment of the present invention.
FIGS. 4A to 4M sequentially illustrate the fabrication process of the hybrid-type microelectrode array according to an embodiment of the present invention.
5 is a cross-sectional view of Fig.
Figure 6 is a cross-sectional view of Figure 4i.
Figure 7 is a cross-sectional view of Figure 4j.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the drawings, the same reference numerals are used to designate the same or similar components throughout the drawings. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

FIG. 1 is a perspective view of a hybrid type microelectrode array according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view taken along line A-A 'of FIG.

Referring to FIGS. 1 and 2, a hybrid type microelectrode array 100 according to the present invention includes a microelectrode 500 and an insulating support 200. The microelectrode (500) includes at least one invasive microelectrode (520) and at least one noninvasive microelectrode (540). Each of the invasive microelectrode 520 and the non-invasive microelectrode 540 has a structure capable of transmitting an electrical signal from one end to the other end, and each of the invasive microelectrode 520 and the non- Is electrically insulated by the support (200). The microelectrode (500) is made of a silicone material, and is formed so as to give a proper stimulation to a specific part of the body or to detect a signal generated from the body according to an external electrical signal.

The invasive microelectrode 520 is higher in height than the noninvasive microelectrode 540 and has a pointed tip, that is, a needle. At least a part of the invasive microelectrode 520 including the tip is inserted into the body part. A second metal layer 700 is formed on the distal end portion of the invasive microelectrode 520. The second metal layer 700 serves as a terminal of the invasive microelectrode 520.

The non-invasive microelectrode 540 is formed in a flat plate shape. Unlike the invasive microelectrode 520, the non-invasive microelectrode 540 does not invade the body part, but contacts the surface of the skin to apply electrical stimulation or extract a signal. A second metal layer 700 serving as a terminal of the non-invasive microelectrode 540 is formed on a part of the upper surface of the non-invasive microelectrode 540.

The first metal layer 600 is formed on the opposite surface of the tip of the invasive microelectrode 520 and on the lower surface of the non-invasive microelectrode 540, respectively. The first metal layer 600 serves as a terminal for electrically connecting the microelectrode 500 with an external device.

The protective layer 800 is formed on the remaining portion of the microelectrode 520 except for the portion where the first metal layer 600 and the second metal layer 700 are formed. The protective film 800 is made of an insulating material and electrically and chemically protects the surface of the fine electrode 520 from the outside. The protective film 800 is formed on the microelectrode 500 to maintain the electrical characteristics of the microelectrode 500 and protect the microelectrode 500 from the external environment. In addition, since the protective film 800 is formed, an electric signal applied through the fine electrode 500 can be transmitted to the body part through the second metal layer 700 alone.

The insulative support 200 supports the microelectrodes 500 to prevent the microelectrodes 500 from being detached from the insulative support 200 or deviating from the positioned arrangement. Also, the insulative support 200 electrically insulates each of the fine electrodes 500 from each other so as not to be electrically connected to each other. Particularly, since the insulative support 200 is formed of a flexible material, the hybrid type microelectrode array 100 according to the present invention can be bent without any additional band or cuffs, And can be stably fixed to the body part. It is preferable that the insulating support 200 of the flexible material is formed of polydimethylsiloxane (PDMS) because PDMS is a transparent inactive polymer having very low surface energy, easy change of shape, Since the PDMS has very strong durability and does not cause degradation of properties even after a long period of time, the PDMS can be suitably used for human fitness It is possible to use the body for a long time or semi-permanently.

Hereinafter, an embodiment for fabricating a hybrid type microelectrode array according to an embodiment of the present invention will be described.

FIG. 3 is a flowchart illustrating a method of fabricating a hybrid type microelectrode array according to an embodiment of the present invention. FIGS. 4A to 4M are views showing a hybrid type microelectrode array according to an embodiment of the present invention. Figs. 5 to 7 are sectional views of Figs. 4G, 4I and 4J, respectively.

The upper surface and the lower surface used in the following description are set based on the silicon wafer 300 shown in FIG. 4A for convenience of explanation. In the present invention, the 'upper surface' It can be an arbitrary one side, and the lower side can be a side facing one arbitrary side.

As shown in FIG. 3, an embodiment of the hybrid type microelectrode array manufacturing method of the present invention includes a step (S10) of preparing a silicon wafer, a step (S20) of forming a groove in the silicon wafer, (S30) of injecting a second insulator into the groove and curing (S40), removing the first insulator (S50), bonding the first insulator to the upper surface of the silicon wafer A step S60 of forming an intrusion type microelectrode, a step of forming a metal layer on the intrusion type microelectrode and the non-invasive type microelectrode S70, a step of forming a protective film on the invasive type microelectrode and the non- .

Hereinafter, the above-described embodiment of the hybrid type microelectrode array manufacturing method will be described in detail.

In order to manufacture the hybrid type microelectrode array 100 according to an embodiment of the present invention, a silicon wafer 300 is first prepared (see FIG. 4A). The silicon wafer 300 has a rectangular parallelepiped shape and has a predetermined area. The shape of the silicon wafer 300 is not limited to the illustrated embodiment, but it is preferable that the upper surface and the lower surface are formed flat. The top and bottom surfaces of the silicon wafer 300 are preferably polished smoothly, and the silicon wafer 300 preferably has good electrical conductivity.

Thereafter, grooves 310 are formed in a predetermined pattern on the upper surface of the silicon wafer 300 (see Figs. 4B and 4C). As a method for forming the grooves 310 in the silicon wafer 300, at least one first groove 312 is linearly formed on the upper surface of the silicon wafer 300 (see FIG. 4B) At least one second groove 314 perpendicular to the longitudinal direction (see Fig. 4C). As a result, the grooves 310 of the lattice pattern are formed on the upper surface of the silicon wafer 300. At this time, the groove 310 may be machined using a tool such as a diamond blade, but it is needless to say that the groove 310 may be formed by other known techniques. As another method for forming the grooves 310 on the upper surface of the silicon wafer 300, a deep reactive ion etching (DRIE) technique may be used. When the grooves 310 are formed in the silicon wafer 300 using the DRIE technique, the surface roughness of the grooves 310 can be adjusted, so that there is no need to separately perform the surface treatment for the grooves 310, which will be described later.

The first metal layer 600 having good conductivity may be deposited on the upper surface of the silicon wafer 300 before forming the trenches 310 on the upper surface of the silicon wafer 300. The first metal layer 600 serves as a terminal for electrically connecting the microelectrode 500 with an external device. The first metal layer 600 may be formed on the upper surface of the silicon wafer 300 before the grooves 310 are formed on the upper surface of the silicon wafer 300, There is an advantage that the first metal layer 600 need not be separately patterned when the metal layer 600 is formed. In other words, when the first metal layer 600 is formed after the groove 310 is formed on the upper surface of the silicon wafer 300, only the remaining portion of the upper surface of the silicon wafer 300 except for the portion where the groove 310 is formed Patterning is required to allow the first metal layer 600 to be formed. The deposition of the first metal layer 600 may be performed by, for example, an E-beam evaporator or a sputtering method.

Next, the hardened first insulator 400 is bonded to the upper surface of the silicon wafer 300 having the groove 310 formed therein (see FIG. 4D). Here, the cured first insulator 400 functions as a lid covering the groove 310, which is temporarily attached to the upper surface of the silicon wafer 300 and then removed, as an insulator formed in a flat plate shape. It is preferable that the first insulator 400 is formed of PDMS because the adhesive force can be controlled by performing surface modification on the PDMS to facilitate the bonding and separation of the first insulator 400 to be. A more detailed description thereof will be described later.

Thereafter, the second insulator 200 is injected into the empty space (hereinafter, referred to as 'channel 330') generated by the first insulator 400 and the silicon wafer 300 and cured (see FIG. 4E) . The channel 330 is a space created by covering the groove 310 formed on the upper surface of the silicon wafer 300 with the first insulator 400. The second insulator 200 is a liquid insulator and is filled in the channel 330. In this case, it is preferable that the step of injecting the second insulator 200 into the channel 330 is performed in a vacuum chamber. This is because the second insulator 200 is vacuum- It is advantageous to set it. In addition, the material of the second insulator 200 is preferably PDMS because of the reason described in the first insulator 400. Accordingly, both the first insulator 400 and the second insulator 200 may be made of PDMS. Furthermore, it is preferable that the first insulator 400 is subjected to an appropriate surface treatment. Hereinafter, the surface treatment will be described.

Hydrophilic surface treatment is applied to the groove 310 formed on the upper surface of the silicon wafer 300 and hydrophobic surface treatment is applied to the surface of the surface of the first insulator 400, particularly the surface bonded to the upper surface of the silicon wafer 300. As described above, since the first insulator 400 is temporarily attached to the upper surface of the silicon wafer 300 and then removed, the hydrophobic surface treatment for the first insulator 400 requires the first insulator 400 The upper surface of the silicon wafer 300 and the second insulator 200 can be easily separated from each other. The hydrophilic surface treatment for the grooves 310 enhances the adhesive force of the silicon pillars formed by the grooves 310 formed on the upper surface of the silicon wafer 300 to form a second insulator 200 ) Is completely bonded to the silicon pillars.

Next, the first insulator 400 is separated from the silicon wafer 300 (see FIG. 4F).

Thereafter, an invasive microelectrode 520 and a noninvasive microelectrode 540 electrically separated from each other by the second insulator 200 are formed on the lower surface of the silicon wafer 300. The method of forming the immersion type microelectrode 520 and the noninvasive type microelectrode 540 that are electrically isolated from each other by the second insulator 200 on the silicon wafer 300 is as follows. The grooves 320 are formed in a lattice pattern using diamond blades on the lower surface to form the silicon pillars 340 (see FIGS. 4G, 4H, 5 and 6). In addition, the non-invasive microelectrode 540, The silicon pillar 340 located at a portion where the silicon pillar 340 is to be formed is removed (see FIG. 4I). At this time, the grooves 320 formed on the lower surface of the silicon wafer 300 are formed in the same pattern as the grooves 310 formed on the upper surface of the silicon wafer 300. The depth of the groove 320 is adjusted so that the second insulator 200 filled on the opposite side of the silicon wafer 300 is not exposed when the groove 320 is processed. A silicon pillar 340 is formed on the lower surface of the silicon wafer 300 by forming the grooves 320 in the silicon wafer 300. The removal of the silicon pillars 340 may be performed after all the grooves 320 have been processed or may be performed together while processing the grooves 320. [ The bottoms of the grooves 320 between the silicon pillars 340 are then removed until the insulating support 200 is exposed (see FIGS. 4J and 7). A silicon pad 360 used as the non-invasive microelectrode 540 is formed by removing the silicon connected between the silicon pillars 340. Each of the silicon pillars 340 and the silicon pads 360 Electrically insulated, and each silicon pillar 340 and silicon pads 360 become independent conductors. Thereafter, the silicon pillar 340 is etched to make the end of the silicon pillar 340 sharp (see FIG. 4K). To sharpen the ends of the silicon pillars 340, for example, isotropic wet etching may be used. By making the tip of the silicon pillar 340 sharp, a micro needle used as the invasive microelectrode 520 is formed. The silicon pillars 340 and the silicon pads 360 are electrically separated by exposing the insulating support 200 by processing the bottoms of the grooves 320 as shown in FIGS. 4H to 4K, The silicon pillar 340 and the silicon pads 360 are electrically disconnected by processing the bottom of the trench 310 after the silicon pillar 340 is first etched to be sharpened It is also possible to process them in the order. However, since the process of forming the grooves 320 on the lower surface of the silicon wafer 300 and the process of processing the bottom of the grooves 320 can be performed in the same processing apparatus, The grooves 320 are formed on the lower surface of the silicon wafer 300 and the bottoms of the grooves 310 are formed on the lower surface of the silicon wafer 300 after the grooves 320 are formed, It is more efficient to perform the etching process later.

Next, a second metal layer 700 is formed on the tip of the sharpened silicon pillar 340 and a part of the upper surface of the non-invasive microelectrode 540 (see FIG. At this time, the second metal layer 700 may be deposited in a thin film form only on a desired site using a deposition mask. The second metal layer 700 serves as a terminal of the microelectrode 500 that applies an electrical signal and senses a signal generated from the body.

A passivation layer 800 is then formed on the remaining portions of the silicon pillar 340 and the silicon pad 360 except for the portion where the second metal layer 700 is formed (see FIG. 4M). The protective film 800 is formed on the microelectrode 500 so that the electric signal applied through the microelectrode 500 can be transmitted to the body part through the second metal layer 700 only. Since the silicon pillar 340 and the silicon pad 360 are made of a highly conductive material, when the protection film 800 is not provided, an electric signal is applied through the entire area of the silicon pillar 340 and the silicon pad 360 . In addition, since the protective film 800 is formed on the microelectrode 500, the electrical characteristics of the microelectrode 500 can be maintained and the microelectrode 500 can be protected from the external environment.

It will be apparent to those skilled in the art that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims. . Therefore, the embodiments disclosed in the present invention are not intended to limit the scope of the present invention but to limit the scope of the technical idea of the present invention. The scope of protection of the present invention should be construed according to the following claims, and all technical ideas within the scope of equivalents should be construed as falling within the scope of the present invention.

100: microelectrode array 200: insulative substrate
300: silicon wafer 400: first insulator
500: fine electrode 520:
540: non-invasive microelectrode 600: first metal layer
700: second metal layer 800: protective film

Claims (16)

delete delete delete delete delete (a) preparing a silicon wafer;
(b) forming a groove having a predetermined pattern on one surface of the silicon wafer;
(c) bonding a first insulator to the one surface of the silicon wafer;
(d) injecting and curing a second insulator into the space between the groove and the first insulator;
(e) removing the first insulator; And
(f) forming non-invasive microelectrodes and non-invasive microelectrodes electrically insulated from each other by the second insulator on the other surface of the silicon wafer,
Wherein the step (a) comprises laminating a first metal layer on one surface of the silicon wafer. The method according to claim 6,
Wherein the first insulator and the second insulator are polydimethylsiloxane. 2. The hybrid type microelectrode array of claim 1, wherein the first insulator and the second insulator are polydimethylsiloxane. The method according to claim 6,
The groove
At least one first groove formed in a straight line on one surface of the silicon wafer; And
And at least one second groove formed in a straight line perpendicular to the first grooves, wherein the second grooves are formed in a lattice pattern. The method according to claim 6,
Wherein the grooves are formed by machining. The method according to claim 6,
Wherein the grooves are formed by depth reactive ion etching (DRIE). The method according to claim 6,
The step (c)
(c1) subjecting the groove to a hydrophilic surface treatment;
(c2) subjecting a surface of the first insulator bonded to one surface of the silicon wafer to a hydrophobic surface treatment; And
(c3) bonding one surface of the silicon wafer to one surface of the first insulator
Wherein the hybrid type microelectrode array comprises a plurality of microelectrodes. The method according to claim 6,
The step (d)
(d1) injecting the second insulator into a space between the groove and the first insulator in a vacuum chamber
Wherein the hybrid type microelectrode array comprises a plurality of microelectrodes. The method according to claim 6,
The step (f)
(f1) forming a silicon pillar on the other surface of the silicon wafer;
(f2) removing the silicon pillar located at a portion where the non-invasive microelectrode is to be formed;
(f3) removing the bottom of the trench between the silicon pillars until the second insulator is exposed; And
(f4) Step of making the ends of the silicon pillars sharp
Wherein the hybrid type microelectrode array comprises a plurality of microelectrodes. delete The method according to claim 6,
The method for producing the hybrid type microelectrode array includes:
After the step (f)
(g) forming a second metal layer on an end of the invasive microelectrode and a part of a top surface of the non-invasive microelectrode. 16. The method of claim 15,
The method for producing the hybrid type microelectrode array includes:
After the step (g)
(h) forming a protective film on the remaining portions of the non-invasive microelectrode and the non-invasive microelectrode on which the first metal layer and the second metal layer are not formed, .

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