Self-filling method for high-aspect-ratio micropores of substrate

Abstract

The invention relates to the technical field of packaging and processing of semiconductor power devices, in particular to a self-filling method for high-aspect-ratio micropores of a substrate, which comprises the following steps of: (1) activating the substrate by using a coupling agent; (2) the surface of the base plate is coated with paste nano filler, the paste nano filler automatically fills the micropores in the base plate under the capillary action, the wetting angle alpha of the paste nano filler is smaller than or equal to 30 degrees, the depth-diameter ratio of the micropores ranges from 5: 1 to 500: 1, and the pore diameter of the micropores ranges from 1 micrometer to 100 micrometers; and (3) carrying out sintering treatment on the substrate subjected to hole filling. According to the method, the tiny micropores with the high depth-diameter ratio in the substrate can be reliably filled, the cost is low, and the method is simple.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor power device packaging and processing, and particularly to a self-filling method for microholes with a high aspect ratio on a substrate. Background Art

[0002] Microhole filling technology is one of the key technologies in integrated circuit manufacturing. Microhole filling technology can achieve the connection of interlayer circuits. Microhole filling technology has been widely applied in the manufacturing of printed circuit boards and integrated circuits, and has broad application prospects in advanced packaging, microelectromechanical systems, and silicon photonics technology.

[0003] For holes with a high aspect ratio, traditional filling processes rely on external equipment (such as vacuum or pressure assistance), and the filling process is complex and costly. For example, for the filling of powder in the interlayer through holes described in Japanese Patent JP2011091117A, a pressurizing jig is used to pressurize the filled powder. Existing hole filling technologies are divided into metal conductive paste hole filling and direct electroplating hole filling. For example, a manufacturing method for filling holes with conductive copper paste on a glass substrate disclosed in Chinese Patent Application CN119095286A uses an electroplating copper process to deposit copper atoms on a copper seed layer to increase the thickness of the copper seed layer on the surface of the substrate layer and the inner wall of the through hole, and uses a vacuum plugging process to fill the through hole with conductive copper paste. This vacuum hole filling method is costly, and the yield is stable only when filling microholes of 100 - 250 microns, which cannot meet the requirements of fine circuits. Another example is a hole filling method for a ceramic substrate disclosed in Chinese Patent Application CN115460798A. Seed layer: A conductive layer is vacuum sputtered on the surface of the ceramic. The through holes drilled by laser on the ceramic form connections of the metal copper layer inside the holes through pulse electroplating. The metal copper layer obtained by this electroplating hole filling technology is prone to generating bubbles or holes, which greatly affects the yield of the substrate and the service life of power devices. Summary of the Invention

[0004] The purpose of the present invention is to propose a self-filling method for microholes with a high aspect ratio on a substrate, which can reliably fill the tiny and high-aspect-ratio microholes on the substrate, with low cost and a simple method.

[0005] To achieve this purpose, the present invention adopts the following technical solutions:

[0006] A self-filling method for microholes with a high aspect ratio on a substrate, comprising the following steps:

[0007] (1) Activate the treatment of the substrate with a coupling agent;

[0008] (2) Coat a paste-like nano filler on the surface of the substrate. The paste-like nano filler self-fills the microholes on the substrate under capillary action. The wetting angle α of the paste-like nano filler ≤ 30°, the aspect ratio of the microholes is 5:1 to 500:1, and the pore diameter of the microholes is 1 - 100 μm;

[0009] (3) Sinter the substrate with the vias filled.

[0010] Furthermore, when the pore diameter of the micro-pores is 1-10 μm, the wetting angle α of the paste-like nano-filler ≤ 15°;

[0011] When the pore diameter of the micro-pores is 10-50 μm, the wetting angle α of the paste-like nano-filler ≤ 20°;

[0012] When the pore diameter of the micro-pores is 50-100 μm, the wetting angle α of the paste-like nano-filler ≤ 30°.

[0013] Furthermore, the paste-like nano-filler contains an interfacial modifier, and the interfacial modifier is selected from amine compounds, low molecular weight alcohols, low molecular weight ethers or organic acids.

[0014] Furthermore, the interfacial modifier is selected from diethylamine, triethylamine, octylamine, ethanol, butanol, diethylene glycol methyl ether, formic acid, acetic acid or citric acid.

[0015] Furthermore, the viscosity of the paste-like nano-filler is 1-10 Pa·s, and the particle size of the metal particles in the paste-like nano-filler is 10-100 nm.

[0016] Furthermore, in the step (1), the substrate is immersed in an acid solution, cleaned and dried, then immersed in an ethanol solution of a coupling agent, and then the substrate is cleaned and dried.

[0017] Furthermore, when the substrate is an organic substrate, the substrate is immersed in an acid solution, cleaned and dried, then the substrate is subjected to plasma treatment, and then the substrate is immersed in an ethanol solution of a coupling agent, and then cleaned and dried.

[0018] Furthermore, the substrate is a glass substrate, a ceramic substrate, an organic substrate or a metal substrate, and the coupling agent is a silane coupling agent or a titanate coupling agent.

[0019] Furthermore, in the step (2), the paste-like nano-filler is coated on the surface of the substrate by a doctor blade coating method, the coating thickness is 10-30 μm, and it is left standing at room temperature. The paste-like nano-filler self-fills the micro-pores on the substrate under capillary action.

[0020] Furthermore, in the step (3), the sintering treatment is as follows: place the substrate in a protective environment, heat it to 200-400 °C at a heating rate of 10-20 °C / min, keep it at a constant temperature for sintering for 5-30 min, and then cool it to room temperature at a rate of 5-10 °C / min.

[0021] The technical solution provided by the present invention may include the following beneficial effects:

[0022] In the present invention, by subjecting the substrate to coupling agent activation treatment, the interfacial bonding force of the surface and the inner wall of the micropores of the substrate is increased, making it easier to be wetted. Based on the paste-like nano filler with a wetting angle α≤30°, by utilizing wettability regulation and capillary action, it can fill the micropores with a high aspect ratio, and has a good filling effect on the micropores with a pore diameter of 1-100 μm and an aspect ratio of 5:1 to 500:1. The method of the present invention realizes the self-filling of the high-aspect-ratio holes of the substrate driven by capillary action without external pressure or vacuum assistance, and the steps are simple and efficient, with low cost and reliable filling effect on the micropores with small pore diameter and high aspect ratio. Specific embodiments

[0023] An embodiment of the present invention provides a self-filling method for high-aspect-ratio micropores of a substrate, which is used to reliably fill the small and high-aspect-ratio micropores on the substrate to enable interlayer circuit connection.

[0024] The method of the present invention includes the following steps:

[0025] (1) Subject the substrate to coupling agent activation treatment;

[0026] (2) Coat a paste-like nano filler on the surface of the substrate, and the paste-like nano filler self-fills the micropores on the substrate under capillary action. The wetting angle α of the paste-like nano filler is ≤30°, the aspect ratio of the micropores is 5:1 to 500:1, and the pore diameter of the micropores is 1-100 μm;

[0027] (3) Sinter the substrate after the hole filling is completed.

[0028] In the present invention, by subjecting the substrate to coupling agent activation treatment, the interfacial bonding force of the surface and the inner wall of the micropores of the substrate is increased, making it easier to be wetted. Based on the paste-like nano filler with a wetting angle α≤30°, by utilizing wettability regulation and capillary action, it can fill the micropores with a high aspect ratio, and has a good filling effect on the micropores with a pore diameter of 1-100 μm and an aspect ratio of 5:1 to 500:1. After filling, sintering the substrate can solidify the inside of the micropores to achieve interlayer circuit connection. The method of the present invention realizes the self-filling of the high-aspect-ratio holes of the substrate driven by capillary action without external pressure or vacuum assistance, and the steps are simple and efficient, with low cost and reliable filling effect on the micropores with small pore diameter and high aspect ratio. The paste-like nano filler can be selected from nano silver paste, nano copper paste, carbon nanotube paste, and graphene paste. Preferably, the paste-like nano filler in the present invention is nano copper paste.

[0029] Specifically, when the pore diameter of the micropores is 1-10 μm, the wetting angle α of the paste-like nano filler is ≤15°;

[0030] When the pore diameter of the micropores is 10 - 50 μm, the wetting angle α of the paste-like nano filler ≤ 20°.

[0031] When the pore diameter of the micropores is 50 - 100 μm, the wetting angle α of the paste-like nano filler ≤ 30°.

[0032] Based on different pore diameters, the wetting angle of the paste-like nano filler is set to ensure that the paste-like nano filler can fill the micropores within a short time. When the pore diameter of the micropores is smaller, the wetting angle of the paste-like nano filler is required to be smaller, so that the paste-like nano filler fills the micropores under the action of capillary driving force, thereby ensuring a reliable filling effect of the micropores.

[0033] To reduce the wetting angle of the paste-like nano filler, further, the paste-like nano filler contains an interfacial modifier, and the interfacial modifier is selected from amine compounds, low molecular weight alcohols, low molecular weight ethers or organic acids.

[0034] The addition of amine compounds, low molecular weight alcohols, low molecular weight ethers and organic acids can all reduce the wetting angle of the paste-like nano filler, and can make the surface tension of the paste-like nano filler lower than 30 mN / m. The interfacial modifier is used to reduce the agglomeration phenomenon between metal particles, interact with metal particles to help enhance the fluidity of the paste-like nano filler, and ensure that the paste-like nano filler fully fills the holes with a high aspect ratio.

[0035] Preferably, the interfacial modifier is selected from diethylamine, triethylamine, octylamine, ethanol, butanol, diethylene glycol methyl ether, formic acid, acetic acid or citric acid.

[0036] Based on the requirements of the wetting angle of the paste-like nano filler for micropores with different pore sizes, the mass fraction of the interfacial modifier in the paste-like nano filler is 0.1 - 3%. Exemplarily, for micropores with a pore diameter of 1 - 10 μm, the mass fraction of the interfacial modifier in the paste-like nano filler is 2 - 3%; for micropores with a pore diameter of 10 - 50 μm, the mass fraction of the interfacial modifier in the paste-like nano filler is 1 - 2%; for micropores with a pore diameter of 50 - 100 μm, the mass fraction of the interfacial modifier in the paste-like nano filler is 0.1 - 1%.

[0037] To further improve the filling effect, the viscosity of the paste-like nano filler is 1 - 10 Pa·s, and the particle size of the metal particles in the paste-like nano filler is 10 - 100 nm. Exemplarily, the viscosity of the paste-like nano filler is 1 Pa·s, 3 Pa·s, 5 Pa·s, 8 Pa·s, 10 Pa·s, and the particle size of the metal particles in the paste-like nano filler is 10 nm, 30 nm, 80 nm, 100 nm.

[0038] In an embodiment of the present invention, in the step (1), the substrate is immersed in an acid solution for soaking treatment. After cleaning and drying, it is immersed in an ethanol solution of a coupling agent, and then the substrate is cleaned and dried.

[0039] Acid treatment can remove oxides and contaminants on the substrate surface and increase polar groups. Then the substrate is immersed in an ethanol solution of a coupling agent, and the interfacial bonding force is increased by chemical bonding on the substrate surface, making it easier to be wetted. It should be noted that soaking the substrate in the ethanol solution of the coupling agent is more conducive to the coupling agent binding to the substrate surface and is easy to clean.

[0040] Specifically, when the substrate is an organic substrate, the substrate is immersed in an acid solution for soaking treatment. After cleaning and drying, the substrate is subjected to plasma treatment, and then the substrate is immersed in an ethanol solution of a coupling agent, and then it is cleaned and dried. The organic substrate treated by plasma is more likely to combine with the coupling agent. Exemplarily, argon or nitrogen is used as the gas source for plasma treatment, and the treatment time is 30 - 300 seconds.

[0041] The method of the present invention is applicable to substrates of various materials. Specifically, the substrate is a glass substrate, a ceramic substrate, an organic substrate or a metal substrate, and the coupling agent is a silane coupling agent or a titanate coupling agent.

[0042] The silane coupling agent reacts with the hydroxyl group (-OH) on the substrate surface through its siloxane group (Si - O - R) to form a chemical bond, and the functional group at the other end (such as amino group, epoxy group) acts. Exemplarily, the silane coupling agent is selected from KH - 550 or KH - 560.

[0043] The glass substrate surface contains silanol groups (Si - OH). The silane coupling agent forms a strong silicon - oxygen bond with the glass substrate through hydrolysis and condensation reactions. The processes of the hydrolysis reaction and the condensation reaction are as follows:

[0044] Hydrolysis reaction: R - Si(OR) 3 +H 2 O → R - Si(OH) 3 +ROH;

[0045] Condensation reaction: R - Si(OH) 3 +Si - OH → R - Si - O - Si+H 2 O.

[0046] Polar groups (such as - COOH, - OH) are introduced into the organic substrate after plasma treatment. The epoxy group of the silane coupling agent undergoes a ring - opening reaction with these polar groups to form a covalent bond. The process is as follows:

[0047] Epoxy ring-opening reaction: R-Si-OH + COOH → R-Si-O-C=O-R.

[0048] There is an oxide layer (M-OH) on the surface of the metal substrate. The silane coupling agent forms a metal-siloxane bond through a condensation reaction. The process is as follows:

[0049] Metal binding reaction: R-Si(OH) 3 + M-OH → R-Si-O-M + H 2 O.

[0050] When the paste-like nano filler is coated on the surface of the substrate, the amino group (-NH 2 ) or epoxy group (-CH-O-CH 2 ) of the silane coupling agent binds to the surface of the metal particles through electrostatic interaction or covalent bond, improving wettability and dispersibility; Exemplarily, when the paste-like nano filler is nano copper paste, the amino group binds to the copper surface: R-NH 2 + CuO → R-NH-Cu.

[0051] The titanate coupling agent (such as NDZ-201) has a titanium-oxygen bond (Ti-O-R), and can react with the hydroxyl group or oxide layer on the surface of the substrate to form a stable chemical bond. There are metal oxides (such as Al-OH, Si-OH) on the surface of the ceramic substrate. The titanate coupling agent binds to the ceramic surface through coordination to form a strong bond. The titanium atom of the titanate coupling agent can form a coordination bond with the oxygen atom in the oxide layer on the surface of the metal particles, improving the adhesion and dispersibility of the filler. When the paste-like nano filler is nano copper paste, the coordination reaction is as follows:

[0052] Ti-O-R + Al-OH → Ti-O-Al + R-OH; Ti-O-R + Cu-OH → Ti-O-Cu + R-OH.

[0053] In an embodiment of the present invention, in the step (2), the paste-like nano filler is coated on the surface of the substrate by a doctor blade coating method, the coating thickness is 10-30 μm, and it is left standing at room temperature. The paste-like nano filler self-fills the micropores on the substrate under capillary action. After the filler fills the micropores after standing, the excess filler on the surface of the substrate is gently scraped off with a doctor blade or a coater. In the present invention, the micropore filling can be completed by simply leaving the paste-like nano filler standing after coating, and the operation steps are simple and reliable.

[0054] In an embodiment of the present invention, in the step (3), the sintering treatment is: placing the substrate in a protective environment, heating it to 200-400 °C at a heating rate of 10-20 °C / minute, sintering at a constant temperature for 5-30 minutes, and then cooling to room temperature at a rate of 5-10 °C / min.

[0055] It is understandable that different pore diameters of the micropores require different sintering temperatures to ensure complete curing of the paste-like nano-filler. Exemplarily, when the pore diameter of the micropores is 1 - 10 μm, the sintering temperature is preferably 200 - 250 °C; when the pore diameter of the micropores is 10 - 50 μm, the sintering temperature is preferably 250 - 350 °C; when the pore diameter of the micropores is 50 - 100 μm, the sintering temperature is preferably 350 - 400 °C.

[0056] The present invention will be further elaborated through the following examples.

[0057] Example 1

[0058] In this example, the micropores of a glass substrate with micropores having a pore diameter of 5 μm are filled, and the depth-to-diameter ratio of the micropores is 100:1. The steps are as follows:

[0059] (1) The glass substrate is immersed in a hydrofluoric acid solution with a mass concentration of 1% for 5 minutes, taken out and rinsed thoroughly with ultrapure water, and then dried at 70 °C for 20 minutes; subsequently, the glass substrate is immersed in a KH 550 ethanol solution with a mass concentration of 0.3% for 40 minutes, taken out and rinsed twice with absolute ethanol, and dried at 60 °C for 10 minutes;

[0060] (2) Diethylamine is added to the purchased nano-copper paste, and vacuum stirring is performed for homogenization treatment. The obtained nano-copper paste has a wetting angle of 10°, a viscosity of 1 Pa·s, and the particle size of the copper particles is 10 - 20 nm; the nano-copper paste with a thickness of 10 - 30 μm is coated on the surface of the glass substrate by the doctor blade coating method, and left to stand at room temperature for 30 minutes, and the nano-copper paste is driven into the micropores by capillary action;

[0061] (3) The filled glass substrate is placed in a nitrogen protection atmosphere for sintering, heated to 300 °C at a rate of 15 °C per minute, held for 15 minutes, and cooled to room temperature at a rate of 5 °C per minute. The obtained glass substrate forms a high-density conductive copper structure.

[0062] Example 2

[0063] In this example, the micropores of a ceramic substrate with micropores having a pore diameter of 30 μm are filled, and the depth-to-diameter ratio of the micropores is 80:1. The steps are as follows:

[0064] (1) The ceramic substrate is immersed in a nitric acid solution with a mass concentration of 3% for 8 minutes, taken out and rinsed thoroughly with ultrapure water, and dried at 90 °C for 20 minutes; subsequently, the ceramic substrate is immersed in an NDZ-201 ethanol solution with a mass concentration of 0.5% for 35 minutes, taken out and rinsed twice with absolute ethanol, and dried at 100 °C for 8 minutes;

[0065] (2) Diethylene glycol methyl ether is added to the purchased nano copper paste, and vacuum stirring is carried out for homogenization treatment. The wetting angle of the obtained nano copper paste is 20°, the viscosity is 10 Pa·s, and the particle size of the copper particles is 20 - 50 nm; The nano copper paste with a thickness of 10 - 30 μm is coated on the surface of the ceramic substrate by the doctor blade coating method, and left standing at room temperature for 30 minutes, and the capillary action is used to drive the copper paste to penetrate into the micropores;

[0066] (3) The filled substrate is placed in a nitrogen protection atmosphere for sintering, heated to 300 °C at a rate of 15 °C / minute, held for 15 minutes, and cooled to room temperature at a rate of 5 °C / minute. The obtained ceramic substrate forms a high-density conductive copper structure.

[0067] Example 3

[0068] In this example, the micropores of an organic substrate with micropores having a pore diameter of 70 μm are filled, and the depth-to-diameter ratio of the micropores is 100:1. The steps are as follows:

[0069] (1) The organic substrate is soaked in an acetic acid solution with a mass concentration of 2% for 4 minutes, taken out, rinsed thoroughly with ultrapure water, and dried at 50 °C for 12 minutes; Using argon as the gas source, the organic substrate is plasma-treated for 200 s. Subsequently, the organic substrate is soaked in a KH-560 ethanol solution with a mass concentration of 0.4% for 30 minutes, taken out, rinsed twice with absolute ethanol, and dried at 60 °C for 12 minutes;

[0070] (2) Acetic acid is added to the purchased nano copper paste, and vacuum stirring is carried out for homogenization treatment. The wetting angle of the obtained nano copper paste is 15°, the viscosity is 8 Pa·s, and the particle size of the copper particles is 20 - 50 nm; The nano copper paste with a thickness of 10 - 30 μm is coated on the surface of the organic substrate by the doctor blade coating method, left standing at room temperature for 30 minutes, and the capillary action is used to drive the copper paste to penetrate into the micropores;

[0071] (3) The filled organic substrate is placed in a nitrogen protection atmosphere for sintering, heated to 300 °C at a rate of 15 °C / minute, held for 15 minutes, and cooled to room temperature at a rate of 5 °C / minute. The obtained organic substrate forms a high-density conductive copper structure.

[0072] Example 4

[0073] In this example, the micropores of a metal substrate with micropores having a pore diameter of 100 μm are filled, and the depth-to-diameter ratio of the micropores is 500:1. The steps are as follows:

[0074] (1) The metal substrate is soaked in a hydrochloric acid solution with a mass concentration of 5% for 6 minutes, taken out, rinsed with absolute ethanol, and naturally dried at room temperature for 15 minutes; Subsequently, the metal substrate is soaked in a KH-550 ethanol solution with a mass concentration of 1% for 50 minutes, taken out, rinsed twice with absolute ethanol, and dried at 60 °C for 20 minutes;

[0075] (2) Citric acid is added to the purchased nano copper paste, and then homogenized by a vacuum stirring device. The obtained nano copper paste has a wetting angle of 30°, a viscosity of 4 Pa·s, and the particle size of copper particles is 60 - 100 nm. The blade coating method is used to coat the metal substrate with a thickness of 10 - 30 μm, and it is left standing at room temperature for 30 minutes, and the capillary action is utilized to drive the copper paste to penetrate into the micropores.

[0076] (3) The filled substrate is placed in a nitrogen - protected atmosphere for sintering. It is heated to 300 °C at a rate of 15 °C per minute, held for 15 minutes, and then cooled to room temperature at a rate of 5 °C per minute to form a high - density conductive copper structure.

[0077] Example 5

[0078] In this example, the micropores of a ceramic substrate with micropores having a pore diameter of 1 μm are filled, and the depth - to - diameter ratio of the micropores is 20:1. The steps are as follows:

[0079] (1) The ceramic substrate is immersed in a nitric acid solution with a mass concentration of 3% for 8 minutes, taken out and rinsed thoroughly with ultrapure water, and dried at 90 °C for 20 minutes. Subsequently, the ceramic substrate is immersed in an NDZ - 201 ethanol solution with a mass concentration of 0.5% for 35 minutes, taken out and rinsed twice with absolute ethanol, and dried at 100 °C for 8 minutes.

[0080] (2) Diethylene glycol methyl ether is added to the purchased nano copper paste, and vacuum stirring is performed for homogenization. The obtained nano copper paste has a wetting angle of 5°, a viscosity of 3 Pa·s, and the particle size of copper particles is 20 - 50 nm. The blade coating method is used to coat the surface of the ceramic substrate with a nano copper paste having a thickness of 10 - 30 μm, and it is left standing at room temperature for 30 minutes, and the capillary action is utilized to drive the copper paste to penetrate into the micropores.

[0081] (3) The filled substrate is placed in a nitrogen - protected atmosphere for sintering. It is heated to 300 °C at a rate of 15 °C per minute, held for 15 minutes, and then cooled to room temperature at a rate of 5 °C per minute, and the obtained ceramic substrate forms a high - density conductive copper structure.

[0082] After testing, the substrates obtained in Examples 1 - 5 can all form high - density conductive copper structures, and the inter - layer circuits have good connection effects.

[0083] Other components and operations of a self - filling method for high - aspect - ratio micropores of a substrate according to an embodiment of the present invention are known to those of ordinary skill in the art, and will not be described in detail here.

[0084] In the description of this specification, the descriptions referring to terms such as "embodiment", "example", etc. mean that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in a suitable manner in any one or more embodiments or examples.

[0085] Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A method for self-filling micropores with a high aspect ratio in a substrate, characterized in that: The following steps are involved: (1) performing a coupling agent activation treatment on the substrate; (2) coating a paste-like nanofiller on the surface of the substrate, wherein the paste-like nanofiller self-fills the micropores on the substrate under capillary action, the wetting angle α of the paste-like nanofiller is ≤30°, the aspect ratio of the micropores is 5:1 to 500:1, and the pore diameter of the micropores is 1-100 μm; (3) The substrate with the holes filled is subjected to a sintering process.

2. The self-filling method of high aspect ratio micro-holes of a substrate according to claim 1, characterized in that: When the pore size of the micropores is 1-10 μm, the wetting angle α of the paste-like nanofiller is ≤15°; When the pore size of the micropores is 10-50 μm, the wetting angle α of the paste-like nanofiller is ≤20°; When the pore diameter of the micropores is 50-100 μm, the wetting angle α of the paste-like nanofiller is ≤30°.

3. The self-filling method of high aspect ratio micro-holes of a substrate according to claim 1 or 2, characterized in that: The paste-like nanofiller contains an interface modifier, and the interface modifier is selected from amine compounds, low molecular weight alcohols, low molecular weight ethers or organic acids.

4. The self-filling method of high aspect ratio micro-holes of a substrate according to claim 3, characterized in that: The interfacial modifier is selected from diethylamine, triethylamine, octylamine, ethanol, butanol, diethylene glycol methyl ether, formic acid, acetic acid or citric acid.

5. The self-filling method of high aspect ratio micro-holes of a substrate according to claim 3, characterized in that: The viscosity of the paste-like nano-filler is 1-10 Pa·s, and the particle size of the metal particles in the paste-like nano-filler is 10-100 nm.

6. The self-filling method of high aspect ratio micro-holes of a substrate according to claim 1, characterized in that: In the step (1), the substrate is immersed in an acid solution, cleaned and dried, and then immersed in an ethanol solution of a coupling agent, and then the substrate is cleaned and dried.

7. The self-filling method of high aspect ratio micro-holes of a substrate according to claim 6, characterized in that: When the substrate is an organic substrate, the substrate is immersed in an acid solution, cleaned and dried, and then plasma treated. Then, the substrate is immersed in an ethanol solution of a coupling agent, and then cleaned and dried.

8. The self-filling method for high aspect ratio micro-holes of a substrate according to claim 6, characterized in that: The substrate is a glass substrate, a ceramic substrate, an organic substrate or a metal substrate, and the coupling agent is a silane coupling agent or a titanate coupling agent.

9. The self-filling method of high aspect ratio micro-holes of a substrate according to claim 1, characterized in that: In the step (2), a paste-like nanofiller is coated on the surface of the substrate by a scraper coating method, with a coating thickness of 10-30 μm. The nanofiller is allowed to stand at room temperature, and the paste-like nanofiller self-fills the micropores on the substrate under capillary action.

10. The self-filling method of high aspect ratio micro-holes in a substrate according to claim 1, characterized in that: In the step (3), the sintering treatment is as follows: placing the substrate in a protective environment, heating to 200-400°C at a heating rate of 10-20°C per minute, sintering at a constant temperature for 5-30 minutes, and then cooling to room temperature at a rate of 5-10°C per minute.