A solvent-free copper paste composition for hole plugging, and a preparation method and application thereof

Abstract

The application discloses a kind of solventless copper paste compositions for hole and its preparation method and application.The composition includes the following weight parts of raw materials: antioxidant conductive copper particles 50~80 parts, resin 10~40 parts and latent curing agent 1~10 parts, wherein, 52 rotor is measured at 20rpm speed at 25 DEG C, and the viscosity value of the resin is 5~30Pa·s, and the glass transition temperature of the resin is 170~180 DEG C.The composition of the present application can effectively solve the existing conductive hole paste (conductive copper paste) short storage period, poor conductivity stability, not ideal high temperature resistance and heat resistance, curing process is prone to hole and shrinkage and other problems.The present application uses ultra-low viscosity, high glass transition temperature resin as matrix, without additional diluent, good process can be realized, so as to avoid the hole caused by diluent volatilization in curing or sintering process.

Description

Technical Field

[0001] This invention relates to the field of PCB processing technology, specifically to a solvent-free copper paste composition for plugging vias, its preparation method, and its application. Background Technology

[0002] Printed circuit boards (PCBs) are the fundamental carriers for achieving electrical connections between electronic components. The manufacturing process of PCBs often employs multi-layer structures, with different stacking designs for the upper and lower layers, such as arbitrary layer interconnection structures or multi-layer through-hole structures. Through-holes are an important component of multi-layer PCBs; each layer typically requires drilling and copper plating before lamination, otherwise interlayer interconnection cannot be achieved.

[0003] In recent years, research on conductive pastes for filling holes in printed circuit boards has gradually increased. A common approach involves adding low-melting-point metal powder and high-melting-point metal powder to flux and resin. Under specific heating conditions, the low-melting-point metal powder melts first and dissolves the high-melting-point metal powder, achieving electrical conductivity within the hole through alloying. This technology currently faces three main problems: 1) High sintering temperature; 2) Existing technologies use at least two types of metal powder, relying on the melting of the low-melting-point metal to wet and dissolve the high-melting-point metal powder to achieve alloying. Therefore, the oxide layer on the surface of the high-melting-point metal powder significantly affects the wettability of the low-melting-point metal on its surface, thus restricting the alloying process; 3) The uniformity of the metal alloy and the alloying reaction rate are difficult to control.

[0004] Currently, although some conductive pastes have added conductive metal powder (such as conductive silver powder) and other conductive components, they are generally two-component products with problems such as high cost, uneven dispersion, poor stability, unstable conductivity, insufficient high temperature and heat resistance, poor flexibility and easy cracking, which makes it difficult to meet the requirements of conductive plugging pastes in circuit board and other fields.

[0005] In recent years, some studies have attempted to replace conductive silver powder with copper powder to reduce costs, but the problem of copper powder's easy oxidation remains unresolved. Furthermore, another important component of conductive copper paste is the solvent. Since the amount of conductive filler added is typically no less than 50%, the viscosity of the resin matrix in the copper paste increases significantly, thus affecting its processing performance. To reduce viscosity and improve processability and rheology, large amounts of solvent or reactive diluents are usually added. However, this not only weakens conductivity but also affects the mechanical properties of the cured material. To ensure storage stability, solvents (or diluents) with larger molecular weights and slower evaporation rates are usually used. These solvents tend to generate numerous pores during the copper paste curing process, adversely affecting the thermal and electrical conductivity at the via plugging points. This greatly limits the application of conductive copper paste in PCB via plugging.

[0006] Therefore, it is of great significance to develop a new solvent-free copper paste composition for plugging holes. Summary of the Invention

[0007] The present invention aims to at least solve one of the technical problems existing in the prior art. To this end, the present invention proposes a solvent-free copper paste composition for plugging holes, which can be stored for a long time and is not prone to pores and shrinkage during the curing process.

[0008] The present invention also proposes a method for preparing the above-mentioned solvent-free copper paste composition for plugging holes.

[0009] The present invention also proposes the application of the above-mentioned solvent-free copper paste composition for plugging holes.

[0010] According to one aspect of the present invention, a solvent-free copper paste composition for plugging holes is provided, comprising the following raw materials in parts by weight: 50-80 parts of antioxidant conductive copper particles, 10-40 parts of resin and 1-10 parts of latent curing agent, wherein the viscosity of the resin is measured to be 5-30 Pa·s at 25°C using a 52 rotor at a rotation speed of 20 rpm, and the glass transition temperature of the resin is 170-180°C.

[0011] The solvent-free copper paste composition for plugging holes according to embodiments of the present invention has at least the following beneficial effects: The composition of the present invention can effectively solve the problems of short shelf life, poor conductivity stability, unsatisfactory high temperature resistance and heat resistance, and easy formation of pores and shrinkage during the curing process of existing conductive plugging pastes (conductive copper paste). To meet the requirements of high thermal conductivity and high electrical conductivity, conductive copper paste needs to add a high content of copper powder, which will lead to a significant increase in the viscosity of the system. Therefore, the present invention uses an ultra-low viscosity, high glass transition temperature resin as the matrix, which can achieve good processability without the addition of additional diluents, thereby avoiding the formation of pores due to diluent volatilization during curing or sintering.

[0012] According to some embodiments of the present invention, the viscosity of the resin is 5 to 15 Pa·s.

[0013] According to some embodiments of the present invention, the viscosity of the resin is 10~30 Pa·s.

[0014] According to some embodiments of the present invention, the resin contains reactive groups. These reactive groups can react with a latent curing agent to form a high-strength, high-toughness, and high-hardness coating.

[0015] According to some embodiments of the present invention, the resin has a flexible silicone-based or epoxy butyl hydroxyl-based branched structure (…). Utilizing extremely low surface tension and high permeability, a spontaneous capillary filling effect is generated during the slurry film formation process, resulting in a dense coating after the plugged holes solidify. This coating is less prone to cracking and possesses high toughness. Epoxy hydroxyl group oxide (HbO) can significantly toughen the copper slurry, making it less susceptible to cracking.

[0016] According to some embodiments of the present invention, the latent curing agent includes at least one of polyamine, acid anhydride, polyamide, polyol, blocked isocyanate or latent dicyandiamide.

[0017] According to some embodiments of the present invention, the method for preparing the antioxidant conductive copper particles includes surface modification treatment of conductive copper powder by a composite antioxidant, wherein the composite antioxidant includes a reducing organic acid, a coupling agent, and an organic antioxidant. The reducing organic acid, coupling agent, and organic antioxidant are compounded to form a composite antioxidant auxiliary, which can provide long-term stable antioxidant protection for copper powder. Specifically, the coupling agent is used for surface modification of copper powder to improve its antioxidant properties and compatibility with organic polymers, thereby improving the dispersibility and adhesion properties of the conductor paste; the organic antioxidant, as an effective corrosion inhibitor for copper, can inhibit the oxidation of copper powder; the reducing organic acid can be used as a liquid-phase reducing agent in the preparation of copper powder, or it can be added to the conductor paste to reduce the oxide film that may form on the surface of the copper powder in subsequent processes.

[0018] According to some embodiments of the present invention, the preparation method of the antioxidant conductive copper particles includes taking conductive copper powder, adding it to a solution containing the composite antioxidant, heating, ultrasonically dispersing, and removing the solvent to obtain the product.

[0019] According to some embodiments of the present invention, the heating temperature is 40~60°C, such as 50°C.

[0020] According to some embodiments of the present invention, the heating time is 45-75 minutes, such as 60 minutes.

[0021] According to some embodiments of the present invention, the heating is performed simultaneously with stirring, and the stirring speed is 300-400 rpm, such as 350 rpm.

[0022] According to some embodiments of the present invention, the solvent of the solution containing the composite antioxidant includes ethanol.

[0023] According to some embodiments of the present invention, the power of the ultrasonic dispersion is 500~600W, such as 560W.

[0024] According to some embodiments of the present invention, the ultrasonic dispersion time is 10-30 minutes, such as 20 minutes.

[0025] According to some embodiments of the present invention, the composite antioxidant comprises the following raw materials in parts by weight: 10-60 parts by weight of reducing organic acid, 5-10 parts by weight of coupling agent and 20-80 parts by weight of organic antioxidant.

[0026] According to some embodiments of the present invention, the reducing organic acid includes at least one of citric acid, tartaric acid, ascorbic acid, maleic acid, or malonic acid.

[0027] According to some embodiments of the present invention, the coupling agent includes at least one of a silane coupling agent or a titanate coupling agent.

[0028] According to some embodiments of the present invention, the organic antioxidant includes nitrogen-containing pentane azoles.

[0029] According to some embodiments of the present invention, the nitrogen-containing five-membered ring azole is selected from at least one of 3-mercapto-1,2,4-triazole, benzotriazole and 5-methylbenzotriazole.

[0030] According to some embodiments of the present invention, the conductive copper powder is in the shape of at least one of flakes or spheres.

[0031] According to some embodiments of the present invention, the average particle size of the conductive copper powder is 500 nm to 30 μm.

[0032] According to some embodiments of the present invention, the raw materials of the solvent-free copper paste composition for plugging holes also include additives.

[0033] According to some embodiments of the present invention, the additive includes a sintering aid, which includes at least one of anhydride-containing structural substances, amine substances, and organic acid substances.

[0034] According to some embodiments of the present invention, the additives include sintering aid I and sintering aid II, and the composition includes antioxidant conductive copper particles, resin, sintering aid I, sintering aid II and latent curing agent, wherein the mass ratio of antioxidant conductive copper particles, resin, sintering aid I, sintering aid II and latent curing agent is 100:12.5~80:0.1~1:0.01~0.05:1.25~20.

[0035] According to some embodiments of the present invention, the sintering aid I is selected from at least one of organic acids or acid anhydrides.

[0036] According to some embodiments of the present invention, the sintering aid I is selected from at least one of oleic acid, malonic acid, or glutaric anhydride.

[0037] According to some embodiments of the present invention, the sintering aid II is selected from at least one of amines or polyethylene glycol.

[0038] According to some embodiments of the present invention, the amines include at least one of the following: 2-amino-2-methyl-1-propanol and triethanolamine.

[0039] According to some embodiments of the present invention, the additive is present in parts by weight of 0.1 to 5, and each part represents the same number of parts by weight as the other raw materials of the solvent-free copper paste composition for plugging holes.

[0040] According to some embodiments of the present invention, the solvent-free copper paste composition for plugging holes comprises the following raw materials in weight percentages: 50-80% antioxidant conductive copper particles, 10-30% resin, 1-10% latent curing agent, and 0.1-5% additives.

[0041] According to another aspect of the present invention, a method for preparing the above-described composition is also provided, comprising the following steps: The antioxidant conductive copper particles are mixed with other raw materials, stirred, and ground to obtain the final product.

[0042] According to some embodiments of the present invention, the stirring speed is 600-800 rpm and the stirring time is 5-15 min.

[0043] According to some embodiments of the present invention, the grinding is performed using a three-roll mill. The grinding process ensures that the components are evenly dispersed.

[0044] According to another aspect of the present invention, the use of the above composition in the preparation of PCB boards is also provided.

[0045] According to another aspect of the invention, the application of the above composition in PCB via plugs is also provided.

[0046] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0047] Fig. 1 The images shown are (a) and (b) X-ray scans of the copper paste composition prepared in Example 1 of this invention after being plugged and cured.

[0048] Fig. 2 This is an X-ray scan of the copper paste composition prepared in Comparative Example 1 of this invention after being cured and plugged. Detailed Implementation

[0049] The following will clearly and completely describe the concept and technical effects of the present invention in conjunction with embodiments, so as to fully understand the purpose, features and effects of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. Other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are all within the scope of protection of the present invention. Unless otherwise specified, the experimental methods used in the embodiments are conventional methods; the materials and reagents used, unless otherwise specified, are commercially available. Unless otherwise specified, the same parameter value is the same in all embodiments. The embodiments described below are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0050] In the description of this invention, references to terms such as "some embodiments" indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0051] In the description of this invention, the use of I, II, etc., is only for the purpose of distinguishing technical features and should not be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated or the order of the technical features indicated.

[0052] The low-viscosity acrylic-modified epoxy resin was purchased from Shikoku Chemical Co., Ltd. of Japan, with the product number L-07N.

[0053] The high-viscosity acrylic-modified epoxy resin was purchased from Guangzhou Tiantai Chemical Co., Ltd., product number TT310.

[0054] The phenoxy resin was purchased from Huntsman Chemicals, catalog number PKHH.

[0055] The phenolic modified resin was purchased from South Asia, product number 601.

[0056] The end-capped isocyanate crosslinking agent was purchased from Lanxess Chemical, catalog number BI7982.

[0057] The dicyandiamide curing agent was purchased from Jiangxi Baisheng Fine Chemicals, product number BS5501.

[0058] The titanate coupling agent was purchased from Hangzhou Jessica Chemical Co., Ltd., product number HY-102.

[0059] Example 1 This example provides a solvent-free copper paste composition for plugging holes, the raw materials of which include antioxidant conductive copper particles, low-viscosity resin, sintering aid, and latent curing agent. The low-viscosity resin is a low-viscosity acrylic-modified epoxy resin, the sintering aid is composed of oleic acid and polyethylene glycol, and the latent curing agent is an end-capped isocyanate crosslinking agent. The mass ratio of the antioxidant conductive copper particles, acrylic-modified epoxy resin, oleic acid, polyethylene glycol, and end-capped isocyanate crosslinking agent is 100:20:0.5:0.03:5.0.

[0060] Its preparation process is as follows: S01. Preparation of antioxidant conductive copper particles: Citric acid, benzotriazole, and silane coupling agent (KH550) are weighed in a mass ratio of 4:4:1 and mixed to prepare 100 mL of 20 wt% ethanol solution. 60 g of flake copper powder with an average particle size of 4 μm is added and stirred at 50 °C for 60 minutes. The mixture is then ultrasonicated in a 560 W ultrasonic cleaner for 20 minutes. The dispersed copper solution is centrifuged and vacuum dried to obtain surface-modified coated copper particles (i.e., antioxidant conductive copper particles).

[0061] S02. The surface-modified copper particles obtained above are mixed with other reagents (low viscosity resin, sintering aid and latent curing agent) and stirred at high speed (700 rpm, stirring for 10 minutes). The mixture is then ground with a three-roll mill (grinding for 4 minutes each at 100 micrometers, 60 micrometers and 30 micrometers) to prepare a sinterable plugging paste.

[0062] Example 2 This example provides a solvent-free copper paste composition for plugging holes, the raw materials of which include antioxidant conductive copper particles, low-viscosity resin, sintering aid, and latent curing agent. The low-viscosity resin is a low-viscosity acrylic-modified epoxy resin, the sintering aid is a mixture of glutaric anhydride and triethanolamine, and the latent curing agent is a dicyandiamide curing agent. The mass ratio of the antioxidant conductive copper particles, acrylic-modified epoxy resin, glutaric anhydride, triethanolamine, and dicyandiamide curing agent is 100:30:0.5:0.03:10.

[0063] Its preparation process is as follows: S01. Preparation of antioxidant conductive copper particles: Citric acid, 5-methylbenzotriazole, and silane coupling agent (KH570) are weighed in a mass ratio of 2.5:6.5:0.5. After mixing, they are prepared into 100 mL of 40 wt% ethanol solution. 80 g of flake copper powder with a particle size D50 of 1~5 μm is added and stirred at 50 °C for 60 minutes. The mixture is then ultrasonicated in a 560 W ultrasonic cleaner for 20 minutes. The dispersed copper solution is centrifuged and vacuum dried to obtain surface-modified coated copper particles (i.e., antioxidant conductive copper particles).

[0064] S02. The surface-modified copper particles obtained above are mixed with other reagents (low viscosity resin, sintering aid and latent curing agent) at high speed, and then ground with a three-roll mill to prepare a sinterable plugging paste.

[0065] Example 3 This example provides a solvent-free copper paste composition for plugging holes, the raw materials of which include antioxidant conductive copper particles, low-viscosity resin, sintering aid, and latent curing agent. The low-viscosity resin is a low-viscosity acrylic-modified epoxy resin, the sintering aid is composed of malonic acid and 2-amino-2-methyl-1-propanol, and the latent curing agent is a dicyandiamide curing agent. The mass ratio of the antioxidant conductive copper particles, acrylic-modified epoxy resin, malonic acid, 2-amino-2-methyl-1-propanol, and dicyandiamide curing agent is 100:25:0.5:0.03:1.5.

[0066] Its preparation process is as follows: S01. Preparation of antioxidant conductive copper particles: Citric acid, 3-mercapto-1,2,4-triazole, and titanate coupling agent are weighed in a mass ratio of 1.5:7.5:0.5. After mixing, they are prepared into 100 mL of 60 wt% ethanol solution. 80 g of flake copper powder with a particle size D50 of 1~5 μm is added and stirred at 50 °C for 60 minutes. The mixture is then ultrasonicated in a 560 W ultrasonic cleaner for 20 minutes. The dispersed copper solution is centrifuged and vacuum dried to obtain surface-modified coated copper particles (i.e., antioxidant conductive copper particles).

[0067] S02. The surface-modified copper particles obtained above are mixed with other reagents (low viscosity resin, sintering aid and latent curing agent) at high speed, and then ground with a three-roll mill to prepare a sinterable plugging paste.

[0068] Comparative Example 1 This example provides a copper paste composition for plugging holes, which differs from Example 1 only in that a high-viscosity resin and diluent are used instead of a low-viscosity resin. Its raw materials include antioxidant conductive copper particles, high-viscosity resin, diluent (diethylene glycol butyl ether acetate), sintering aid, and latent curing agent. The high-viscosity resin is a high-viscosity acrylic-modified epoxy resin, the sintering aid is composed of oleic acid and polyethylene glycol, and the latent curing agent is an end-capped isocyanate crosslinking agent. The mass ratio of antioxidant conductive copper particles, high-viscosity acrylic-modified epoxy resin, diluent, oleic acid, polyethylene glycol, and end-capped isocyanate crosslinking agent is 100:20:45:0.5:0.03:6.5.

[0069] Its preparation process is as follows: S01. Preparation of antioxidant conductive copper particles: Citric acid, benzotriazole, and silane coupling agent (KH550) are weighed in a mass ratio of 4:4:1 and mixed to prepare 100 mL of 20 wt% ethanol solution. 60 g of flake copper powder with a particle size D50 of 1~5 μm is added and stirred at 50 °C for 60 minutes. The mixture is then ultrasonicated in a 560 W ultrasonic cleaner for 20 minutes. The dispersed copper solution is centrifuged and vacuum dried to obtain surface-modified coated copper particles (i.e., antioxidant conductive copper particles).

[0070] S02. The surface-modified copper particles obtained above are mixed with other reagents (high viscosity resin, diluent, sintering aid and latent curing agent) at high speed, and then ground with a three-roll mill to prepare a sinterable plugging paste.

[0071] Comparative Example 2 This example provides a copper paste composition for plugging holes, which differs from Example 1 only in that the copper particles are unmodified. The raw materials include unmodified copper particles, low-viscosity resin, sintering aid, and latent curing agent. The low-viscosity resin is a low-viscosity acrylic-modified epoxy resin, the sintering aid consists of oleic acid and polyethylene glycol, and the latent curing agent is an end-capped isocyanate crosslinking agent. The mass ratio of unmodified copper particles, low-viscosity acrylic-modified epoxy resin, oleic acid, polyethylene glycol, and end-capped isocyanate crosslinking agent is 100:40:45:0.5:0.03:9.5.

[0072] Its preparation process is as follows: S01. Take 100mL of ethanol, add 60g of flake copper powder with a particle size D50 of 1~5μm, stir at 50℃ for 60 minutes, sonicate in a 560W ultrasonic cleaner for 20 minutes, centrifuge the dispersed copper solution, and vacuum dry to obtain unmodified copper particles.

[0073] S02. The unmodified copper particles obtained above are mixed with other reagents (low viscosity resin, sintering aid and latent curing agent) at high speed, and then ground with a three-roll mill to prepare a sinterable plugging paste.

[0074] The copper paste compositions for plugging holes prepared in the above examples and comparative examples were subjected to simulated curing experiments, and the change rate of volume resistivity after initial and multiple reflow soldering was compared and tested.

[0075] Test case The slurry was filled into 75µm diameter through-holes using a 100µm thick stencil printing method. The hole depth was 200µm, and the diameter-to-depth ratio was 0.375. The slurry was heat-cured at 80°C for 20 minutes under a nitrogen atmosphere, followed by heat-curing at 180°C for 30 minutes. The performance of the slurry before and after curing was evaluated.

[0076] The performance evaluation method is as follows: 1) Morphological characteristics: 1. Cut the sample along the axis of the through hole to expose the longitudinal section of the through hole; 2. The cut cross-section is finely polished to make its surface smooth and flat, which is convenient for subsequent microscopic observation; 3. Use an optical microscope to obtain high-resolution cross-sectional images of the internal structure of the through hole, and analyze and evaluate whether there are defects such as voids or incomplete filling inside the hole.

[0077] The characterization results of Example 1 and Comparative Example 1 are as follows: Figs. 1-2 As shown in the figure, the cross-sectional morphology of the copper paste composition of Example 1 after plugging and curing is good and there are no voids; while the conventional conductive copper paste of Comparative Example 1, which uses solvents or diluents, has a large number of voids after plugging and curing.

[0078] (2) Viscosity and solid content test The viscosity of the copper paste composition was tested using a DV-II+Pro cone viscometer with a No. 52 rotor at 25°C and 20 rpm. The test results of the examples and comparative examples are shown in Table 1 below.

[0079] (3) Resistivity test The resistivity of copper paste was measured using an HPS58006D four-probe resistivity meter.

[0080] The specific method is as follows: 1. Apply the prepared copper paste composition for plugging holes to the glass substrate using a coating machine, and sinter at 180°C for 60 minutes under a nitrogen atmosphere to obtain a conductive copper film; 2. Measure the thickness of the copper film sample after high-temperature sintering; 3. Set the corresponding parameters in the resistance tester, adjust the four probes above the sample to be tested, and then press them down vertically to touch them lightly; 4. Record the resistivity and other data after the readings stabilize.

[0081] The test results of Example 1 and Comparative Examples 1-2 are shown in Table 1 below.

[0082] Table 1. Solid content and resistivity test results of Example 1 and Comparative Examples 1-2

[0083] As can be seen from the table above, the stability of Examples 1-3 was significantly improved due to the antioxidant treatment of the copper powder. The stability of Comparative Example 1 decreased significantly due to the addition of a solvent. Comparative Example 2, due to the high viscosity of the conventional resin, did not require the addition of a solvent, resulting in improved stability compared to Comparative Example 1. However, the high resin viscosity led to a decrease in the amount of conductive particles added, resulting in a significant decrease in conductivity.

[0084] The embodiments of the present invention have been described in detail above, but the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. A solvent-free copper paste composition for plugging holes, characterized in that: The raw materials include the following parts by weight: 45-88 parts of antioxidant conductive copper particles, 10-40 parts of resin and 1-15 parts of latent curing agent. The viscosity of the resin is measured to be 5-30 Pa·s at 25°C with a 52 rotor at a speed of 20 rpm. The glass transition temperature of the resin is 170-180°C.

2. The solvent-free copper paste composition for plugging holes according to claim 1, characterized in that: The viscosity of the resin is 5~15 Pa·s; and / or, the viscosity of the resin is 10~30 Pa·s.

3. The solvent-free copper paste composition for plugging holes according to claim 1, characterized in that: The resin contains reactive functional groups.

4. The solvent-free copper paste composition for plugging holes according to claim 1, characterized in that: The resin has a flexible silicone base or an epoxy butyl hydroxyl branch.

5. The solvent-free copper paste composition for plugging holes according to claim 1, characterized in that: The latent curing agent includes at least one of polyamine, acid anhydride, polyamide, polyol, blocked isocyanate, or latent dicyandiamide.

6. The solvent-free copper paste composition for plugging holes according to claim 1, characterized in that: The method for preparing the antioxidant conductive copper particles includes surface modification treatment of conductive copper powder by means of a composite antioxidant, wherein the composite antioxidant includes reducing organic acids, coupling agents and organic antioxidants.

7. The solvent-free copper paste composition for plugging holes according to claim 1, characterized in that: The additives include sintering aids, which include at least one of acid anhydride structural substances, amine substances, and organic acid substances.

8. The method for preparing the solvent-free copper paste composition for plugging holes according to any one of claims 1 to 7, characterized in that: Includes the following steps: The antioxidant conductive copper particles are mixed with other raw materials, stirred, and ground to obtain the final product.

9. The use of the solvent-free copper paste composition for plugging vias according to any one of claims 1 to 7 in the preparation of PCB boards.

10. The use of the solvent-free copper paste composition for plugging vias according to any one of claims 1 to 7 in PCB via plugging.

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