A conductive silver paste for microwave dielectric ceramic filters and its preparation method

Abstract

This invention discloses a conductive silver paste for microwave dielectric ceramic filters and its preparation method. The conductive silver paste of this invention comprises, by weight fraction, the following raw materials: 82%–88% silver powder, 1%–3% glass powder, 0.5%–2% additives, 0.5%–2.5% low-melting-point inorganic powder, and 8%–15% organic carrier. The preparation method of this invention includes: weighing the raw materials according to the weight fractions, mixing and pre-stirring the silver powder, glass powder, additives, low-melting-point inorganic powder, and organic carrier; after stirring and dispersing, mixing and grinding the slurry to ensure a fineness ≤10μm; and filtering to obtain the conductive silver paste. The conductive silver paste prepared by this invention exhibits good conductivity, excellent solderability, high adhesion, and a complete, dense, and bright metal layer surface after sintering.

Description

Technical Field

[0001] This invention relates to the field of electronic materials technology for microwave dielectric ceramic filters, and specifically to a conductive silver paste for microwave dielectric ceramic filters and its preparation method. Background Technology

[0002] Ceramic dielectric filters possess advantages such as small size, light weight, low loss, and high Q value, giving them a dominant position in 5G applications and gradually becoming the mainstream in the filter industry. Conductive silver paste is one of the key materials essential for filter metallization. The conductivity of the conductive silver paste and the density of the conductive layer formed by it have a significant impact on filter performance. Besides the filter dielectric and the Q value of the ceramic itself, a silver electrode layer with good consistency, high density, strong adhesion, and good conductivity is a crucial factor affecting filter insertion loss.

[0003] Currently, although there are many methods for preparing silver paste on the market, their performance in microwave dielectric ceramic filters is often less than ideal, generally exhibiting low Q-values, high insertion loss, high adhesion, or low adhesion, high Q-value, and low loss. Among the factors affecting the performance of conductive silver paste, besides silver powder being the key factor, the added glass powder and inorganic substances are also crucial, and they have a mutually restrictive relationship with the product's performance. According to relevant patent literature, the adhesion between the metal layer and the ceramic is mainly provided by the glass powder and inorganic substances. During high-temperature sintering, the glass powder transforms into a liquid phase, providing adhesion between the metal layer and the ceramic. The added inorganic materials are generally aluminum oxide, copper oxide, nickel oxide, magnesium oxide, etc. They can bond the interlocking structure between the metal layer and the ceramic and enhance the adhesion. However, the melting point and sintering temperature of inorganic materials are generally above 1200℃. When they are co-melted and sintered with glass powder, the melting temperature of the glass powder itself will be increased, affecting the sintering aid effect of the glass powder. Furthermore, if the inorganic materials cannot be completely melted, they are prone to forming single crystal particles between the metal layers, resulting in low density and affecting conductivity and welding performance. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide a conductive silver paste for microwave dielectric ceramic filters and its preparation method. The conductive silver paste exhibits good conductivity, excellent solderability, high adhesion, and a complete, dense, and glossy metal layer surface after sintering.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A conductive silver paste for a microwave dielectric ceramic filter, by weight fraction, is made from the following raw materials:

[0007]

[0008] Preferably, the silver powder is a mixture of flake silver powder and silver micro powder, wherein the weight of the flake silver powder is 10% to 20% of the weight of the silver micro powder; the average particle size of the flake silver powder is 1.2 to 2.5 μm, and the tap density is 3.5 to 4.5 g / cm³. 3 The silver micropowder has an average particle size of 1.5–3.5 μm and a tap density of 4.5–5.5 g / cm³. 3 .

[0009] Preferably, the glass powder is prepared by weighing 55%–60% bismuth trioxide, 8%–15% silicon dioxide, 12%–20% boric acid, 2%–5% aluminum oxide, 1%–3% copper oxide, and 1%–3% zinc oxide by weight, pouring them into a ball mill jar, ball milling, and then discharging the material at 120–150°C. The dried powder is then heated at 1000–1150°C for 30–120 minutes. After heating, the solution is water quenched, ball milled to refine the powder, dried, and sieved to obtain the glass powder with a particle size of 1–3 μm.

[0010] Preferably, the adjuvant is one or more of castor oil, fish oil, lecithin, trimethyl phosphate, Span 85, or polymethacrylamide.

[0011] Preferably, the preparation method of the low-melting-point inorganic powder is as follows: accurately weigh CaCO3, MgO, Li2CO3, ZnO and SiO2 and pour them into a ball mill jar. After ball milling, discharge the material and dry it at 120-150℃ and sieve it. Compact the dried powder and pre-calcine it at 750-850℃ at a heating rate of 3-5℃ / min. Hold it at this temperature for 3-4 hours, cool it with the furnace, and then ball-mill it again. Dry and sieve the powder to obtain the low-melting-point inorganic powder. The chemical composition of the inorganic powder is CaMg 1-x-y Li 2x Zn y Si2O6 (0.1≤x≤0.5, 0.1≤y≤0.35).

[0012] Preferably, the organic carrier is prepared by weighing 10%–30% ethyl cellulose, 6%–13% modified thermosetting acrylic resin, 3%–7% plasticizer, and 55%–75% solvent by weight, mixing them, heating to 70–80°C and stirring for 2–6 hours, and then filtering to obtain the organic carrier.

[0013] Preferably, the plasticizer is one or more of dibutyl phthalate, dioctyl phthalate, or tributyl citrate; and the solvent is one or more of terpineol, butyl carbitol, butyl carbitol acetate, ethylene glycol ethyl ether acetate, ethylene glycol monobutyl ether, tributyl citrate, or cyclohexanone.

[0014] A method for preparing conductive silver paste for microwave dielectric ceramic filters includes the following steps: weighing raw materials according to weight fractions, mixing and pre-stirring silver powder, glass powder, additives, low-melting-point inorganic powder, and organic carrier, stirring at 200-500 rpm for 2-6 hours, grinding the dispersed and stirred slurry 3-8 times to confirm that the fineness is ≤10μm, and filtering to obtain the conductive silver paste.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] The silver micropowder used in this invention serves as the main framework material in conductive materials, providing a fundamental guarantee for the conductivity of the metal layer. The combined flake silver powder can fill the gaps between the silver micropowder particles, and the flake silver powder has high sintering activity. In high-temperature reaction sintering, it can enhance the connection between silver powder grains and improve density.

[0017] The inorganic additive used in this invention is a self-developed and synthesized Ca-Mg-Li-Si-Zn low-melting-point inorganic powder. The pre-sintered powder has a softening temperature between 800 and 900°C. When sintered in combination with glass powder, it can better generate melt and precipitate crystals. It easily reacts with Ti and Al ions in microwave ceramics to form solid solutions, better embedding itself on the ceramic surface without damaging the ceramic's crystal structure, thereby reducing polarization loss and insertion loss. The low-melting-point inorganic powder synthesized in this invention can act as a skeleton material and nucleating agent in the system, reducing the fluidity of molten glass powder, preventing the sedimentation of conductive silver powder, and improving the conductivity and solderability of conductive silver paste.

[0018] The organic carriers used in this invention are ethyl cellulose and modified thermosetting acrylic resin. Ethyl cellulose provides good flexibility and thixotropic properties to the slurry, while the modified thermosetting acrylic resin provides strong drying hardness and adhesion to the slurry after drying, ensuring that the dried metal layer is not easily damaged or detached during movement and has an intact metal surface.

[0019] The conductive silver paste prepared by this invention has good conductivity, excellent solderability, high adhesion, and the surface of the metal layer after sintering is complete, dense, and bright. Attached Figure Description

[0020] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some schematic diagrams of certain embodiments of the present invention, and therefore should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 The sintered appearance of the conductive silver paste metal layer prepared according to the present invention;

[0022] Figure 2 The appearance of the conductive silver paste metal layer crystal phase obtained in Example 1 of this invention;

[0023] Figure 3 The appearance of the conductive silver paste metal layer crystal phase obtained in Example 2 of this invention;

[0024] Figure 4 The appearance of the conductive silver paste metal layer crystal phase obtained in Example 3 of this invention;

[0025] Figure 5 The appearance of the conductive silver paste metal layer crystal phase obtained in Example 4 of this invention;

[0026] Figure 6 The image shows the crystalline phase appearance of the conductive silver paste metal layer obtained in Example 5 of this invention. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. Of course, the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0028] The term “and / or” as used herein refers to and covers any and all possible combinations of one or more of the associated listed items.

[0029] Unless otherwise specified, all chemical reagents and materials in this invention are purchased from the market or synthesized from raw materials purchased from the market.

[0030] Example 1

[0031] A conductive silver paste for a microwave dielectric ceramic filter, by weight fraction, is made from the following raw materials:

[0032] Silver powder 84%; glass powder 1.8%; lecithin 0.5%; low-melting-point inorganic powder 1.1%; organic carrier 12.6%.

[0033] The silver powder is a mixture of flake silver powder and micron silver powder, wherein the weight of the flake silver powder is 10% of the weight of the micron silver powder; the average particle size of the flake silver powder is 1.2–2.5 μm, and the tap density is 3.5 g / cm³. 3 The silver micropowder has an average particle size of 1.5–3.5 μm and a tap density of 4.5 g / cm³. 3 .

[0034] The glass powder is prepared as follows: 59% bismuth trioxide, 13.2% silicon dioxide, 19% boric acid, 3.5% aluminum oxide, 2.5% copper oxide, and 2.8% zinc oxide are weighed by weight and poured into a ball mill jar. After ball milling, the powder is discharged and dried at 120°C. The dried powder is then heated at 1000°C for 120 minutes. After heating, the solution is water quenched, ball milled to refine it, and dried and passed through a 120-mesh sieve to obtain the glass powder.

[0035] The preparation method of the low-melting-point inorganic powder is as follows: accurately weigh 36.38% CaCO3, 8.79% MgO, 6.71% Li2CO3, 4.43% ZnO and 43.68% SiO2 and pour them into a ball mill jar. After ball milling, discharge the material, dry it at 120℃ and sieve it. Compact the dried powder, raise the temperature to 850℃ at a heating rate of 5℃ / min for pre-calcination, keep it at that temperature for 4 hours, cool it with the furnace, and then ball mill it again. After drying and sieving, the low-melting-point inorganic powder is obtained.

[0036] The organic carrier is prepared by weighing 18.5% ethyl cellulose, 6.5% modified thermosetting acrylic resin, 3.5% dibutyl phthalate, and 71.5% butyl carbitol acetate by weight fraction, mixing them, heating to 75°C and stirring for 2 hours, and then filtering to obtain the organic carrier.

[0037] A method for preparing conductive silver paste for microwave dielectric ceramic filters is as follows: 84% silver powder, 1.8% glass powder, 0.5% lecithin, 1.1% low-melting-point inorganic powder, and 12.6% organic carrier are weighed and mixed and pre-stirred according to the following weight fractions. The mixture is stirred at 350 rpm for 6 hours. The dispersed and stirred slurry is then ground 8 times using a three-roll mill to confirm that the fineness is ≤10μm. After filtration, the conductive silver paste is obtained.

[0038] Example 2

[0039] A conductive silver paste for a microwave dielectric ceramic filter, by weight fraction, is made from the following raw materials:

[0040] Silver powder 83%; glass powder 1.5%; trimethyl phosphate 0.5%; low-melting-point inorganic powder 0.9%; organic carrier 14.1%.

[0041] The silver powder is a mixture of flake silver powder and micron silver powder, wherein the weight of the flake silver powder is 15% of the weight of the micron silver powder; the average particle size of the flake silver powder is 1.2–2.5 μm, and the tap density is 3.5 g / cm³. 3 The silver micropowder has an average particle size of 1.5–3.5 μm and a tap density of 5.0 g / cm³. 3 .

[0042] The glass powder is prepared as follows: 58% bismuth trioxide, 15% silicon dioxide, 18.7% boric acid, 3.8% aluminum oxide, 2.3% copper oxide, and 2.2% zinc oxide are weighed according to their weight fractions, poured into a ball mill jar, ball-milled, and then discharged and dried at 130°C. The dried powder is then heated at 1000°C for 120 minutes. After heating, the solution is water-quenched, ball-milled to refine it, and dried and passed through a 120-mesh sieve to obtain the glass powder.

[0043] The preparation method of the low-melting-point inorganic powder is as follows: accurately weigh 36.32% CaCO3, 8.48% MgO, 8.04% Li2CO3, 3.54% ZnO and 43.61% SiO2 and pour them into a ball mill jar. After ball milling, discharge the material, dry it at 130℃ and sieve it. Compact the dried powder, raise the temperature to 750℃ at a heating rate of 3℃ / min for pre-calcination, keep it at that temperature for 3 hours, cool it with the furnace, and then ball mill it again. After drying and sieving, the low-melting-point inorganic powder is obtained.

[0044] The organic carrier is prepared by weighing 17.5% ethyl cellulose, 8% modified thermosetting acrylic resin, 3% tributyl citrate, and 71.5% butyl carbitol by weight, mixing them, heating to 70°C and stirring for 3 hours, and then filtering to obtain the organic carrier.

[0045] A method for preparing conductive silver paste for microwave dielectric ceramic filters is as follows: 83% silver powder, 1.5% glass powder, 0.5% trimethyl phosphate, 0.9% low-melting-point inorganic powder, and 14.1% organic carrier are weighed and mixed and pre-stirred according to the following weight fractions. The mixture is stirred at 500 rpm for 2 hours. The dispersed and stirred slurry is then ground 8 times using a three-roll mill to confirm that the fineness is ≤10μm. After filtration, the conductive silver paste is obtained.

[0046] Example 3

[0047] A conductive silver paste for a microwave dielectric ceramic filter, by weight fraction, is made from the following raw materials:

[0048] Silver powder 84%; glass powder 1.7%; polymethacrylamide 0.5%; low-melting-point inorganic powder 1.3%; organic carrier 12.5%.

[0049] The silver powder is a mixture of flake silver powder and micron silver powder, wherein the weight of the flake silver powder is 15% of the weight of the micron silver powder; the average particle size of the flake silver powder is 1.2–2.5 μm, and the tap density is 4.5 g / cm³. 3 The silver micropowder has an average particle size of 1.5–3.5 μm and a tap density of 5.5 g / cm³. 3 .

[0050] The glass powder is prepared as follows: 60% bismuth trioxide, 14.3% silicon dioxide, 16.9% boric acid, 4.2% aluminum oxide, 2.5% copper oxide, and 2.1% zinc oxide are weighed according to their weight fractions, poured into a ball mill jar, ball-milled, and then discharged and dried at 140°C. The dried powder is then heated at 1100°C for 90 minutes. After heating, the solution is water-quenched, ball-milled to refine it, dried, and passed through a 120-mesh sieve to obtain the glass powder.

[0051] The preparation method of the low-melting-point inorganic powder is as follows: accurately weigh 36.30% CaCO3, 8.48% MgO, 7.50% Li2CO3, 4.13% ZnO and 43.58% SiO2 and pour them into a ball mill jar. After ball milling, discharge the material, dry it at 140℃ and sieve it. Compact the dried powder, raise the temperature to 800℃ at a heating rate of 4℃ / min for pre-calcination, keep it at that temperature for 4 hours, cool it with the furnace, and then ball mill it again. After drying and sieving, the low-melting-point inorganic powder is obtained.

[0052] The organic carrier is prepared by weighing 18% ethyl cellulose, 7.5% modified thermosetting acrylic resin, 3.6% dioctyl phthalate, and 70.9% cyclohexanone by weight, mixing them, heating to 75°C and stirring for 5 hours, and then filtering to obtain the organic carrier.

[0053] A method for preparing conductive silver paste for microwave dielectric ceramic filters is as follows: 84% silver powder, 1.7% glass powder, 0.5% polymethacrylamide, 1.3% low-melting-point inorganic powder, and 12.5% ​​organic carrier are weighed and mixed and pre-stirred at 400 rpm for 3 hours. The dispersed and stirred slurry is then ground 5 times using a three-roll mill to confirm that the fineness is ≤10μm. After filtration, the conductive silver paste is obtained.

[0054] Example 4

[0055] A conductive silver paste for a microwave dielectric ceramic filter, by weight fraction, is made from the following raw materials:

[0056] Silver powder 85%; glass powder 2.0%; lecithin 0.5%; low-melting-point inorganic powder 1.1%; organic carrier 11.4%.

[0057] The silver powder is a mixture of flake silver powder and silver micro powder, wherein the weight of the flake silver powder is 20% of the weight of the silver micro powder; the average particle size of the flake silver powder is 1.2–2.5 μm, and the tap density is 4.0 g / cm³. 3 The silver micropowder has an average particle size of 1.5–3.5 μm and a tap density of 5.0 g / cm³. 3 .

[0058] The glass powder is prepared as follows: 58% bismuth trioxide, 14.5% silicon dioxide, 19% boric acid, 3.3% aluminum oxide, 2.7% copper oxide, and 2.5% zinc oxide are weighed by weight and poured into a ball mill jar. After ball milling, the powder is discharged and dried at 150°C. The dried powder is then heated at 1150°C for 30 minutes. After heating, the solution is water quenched, ball milled to refine it, and dried and passed through a 120-mesh sieve to obtain the glass powder.

[0059] The preparation method of the low-melting-point inorganic powder is as follows: accurately weigh 36.27% CaCO3, 8.47% MgO, 6.69% Li2CO3, 5.01% ZnO and 43.55% SiO2 and pour them into a ball mill jar. After ball milling, discharge the material, dry it at 150°C and sieve it. Compact the dried powder, raise the temperature to 850°C at a heating rate of 5°C / min for pre-calcination, keep it at that temperature for 4 hours, cool it with the furnace, and then ball mill it again. After drying and sieving, the low-melting-point inorganic powder is obtained.

[0060] The organic carrier is prepared by weighing 19% ethyl cellulose, 7% modified thermosetting acrylic resin, 3.5% dibutyl phthalate, and 70.5% butyl carbitol acetate by weight fraction, mixing them, heating to 75°C and stirring for 4 hours, and then filtering to obtain the organic carrier.

[0061] A method for preparing conductive silver paste for microwave dielectric ceramic filters is as follows: 85% silver powder, 2.0% glass powder, 0.5% lecithin, 1.1% low-melting-point inorganic powder, and 11.4% organic carrier are weighed and mixed and pre-stirred according to the following weight fractions. The mixture is stirred at 300 rpm for 5 hours. The dispersed and stirred slurry is then ground 8 times using a three-roll mill to confirm that the fineness is ≤10μm. After filtration, the conductive silver paste is obtained.

[0062] Example 5

[0063] A conductive silver paste for a microwave dielectric ceramic filter, by weight fraction, is made from the following raw materials:

[0064] Silver powder 86%; glass powder 1.5%; lecithin 0.5%; low-melting-point inorganic powder 1.5%; organic carrier 10.5%.

[0065] The silver powder is a mixture of flake silver powder and micron silver powder, wherein the weight of the flake silver powder is 10% of the weight of the micron silver powder; the average particle size of the flake silver powder is 1.2–2.5 μm, and the tap density is 4.5 g / cm³. 3 The silver micropowder has an average particle size of 1.5–3.5 μm and a tap density of 4.5 g / cm³. 3 .

[0066] The glass powder is prepared as follows: 59% bismuth trioxide, 14% silicon dioxide, 18% boric acid, 4.5% aluminum oxide, 2.2% copper oxide, and 2.3% zinc oxide are weighed by weight and poured into a ball mill jar. After ball milling, the powder is discharged and dried at 150°C. The dried powder is then heated at 1000°C for 120 minutes. After heating, the solution is water quenched, ball milled to refine it, and dried and passed through a 120-mesh sieve to obtain the glass powder.

[0067] The preparation method of the low-melting-point inorganic powder is as follows: accurately weigh 35.97% CaCO3, 7.39% MgO, 8.49% Li2CO3, 4.97% ZnO and 43.18% SiO2 and pour them into a ball mill jar. After ball milling, discharge the material, dry it at 150°C and sieve it. Compact the dried powder, raise the temperature to 850°C at a heating rate of 5°C / min for pre-calcination, keep it at that temperature for 4 hours, cool it with the furnace, and then ball mill it again. After drying and sieving, the low-melting-point inorganic powder is obtained.

[0068] The organic carrier is prepared by weighing 16.5% ethyl cellulose, 8.5% modified thermosetting acrylic resin, 3.4% dibutyl phthalate, and 71.6% butyl carbitol acetate by weight fraction, mixing them, heating to 80°C and stirring for 6 hours, and then filtering to obtain the organic carrier.

[0069] A method for preparing conductive silver paste for microwave dielectric ceramic filters is as follows: 86% silver powder, 1.5% glass powder, 0.5% lecithin, 1.5% low-melting-point inorganic powder, and 10.5% organic carrier are weighed and mixed and pre-stirred at 200 rpm for 6 hours. The dispersed and stirred slurry is then ground 8 times using a three-roll mill to confirm a fineness ≤10 μm. After filtration, the conductive silver paste is obtained.

[0070] The viscosity, appearance, solderability, adhesion, and Q-value of the conductive silver pastes prepared in Examples 1 to 5 were measured. Viscosity was measured using a Brookfield DV2T / 4# rotor viscometer at 25°C. The sintered appearance of the metal layer was observed under a microscope. The solderability of the metal layer was tested according to GB / T 17473.7-2008 "Test Methods for Noble Metal Pastes for Microelectronics Technology". Adhesion was obtained by vertically pulling the solder line using a tensile testing machine. The Q-value was tested using the shielded chamber resonance method. The test data are shown in Table 1.

[0071] Table 1 Test data for Examples 1 to 5

[0072]

[0073] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A conductive silver paste for a microwave dielectric ceramic filter, characterized in that, The conductive silver paste is made from the following raw materials by weight percentage: Silver powder 82%~88%; Glass powder 1%~3%; Additives 0.5%~2%; Low-melting-point inorganic powders: 0.5%~2.5%; Organic carrier 8%~15%; The preparation method of the low-melting-point inorganic powder is as follows: Accurately weigh CaCO3, MgO, Li2CO3, ZnO, and SiO2 and pour them into a ball mill jar. After ball milling, discharge the powder and dry it at 120-150℃, then sieve it. Compact the dried powder and pre-calcine it at 750-850℃ at a heating rate of 3-5℃ / min, holding it at this temperature for 3-4 hours. After cooling with the furnace, perform a second ball milling, dry, and sieve to obtain the low-melting-point inorganic powder. The chemical composition of the inorganic powder is CaMg. 1-x-y Li 2x Zn y Si2O6, 0.1≤x≤0.5, 0.1≤y≤0.35; The silver powder is a mixture of flake silver powder and silver micro powder, wherein the weight of the flake silver powder is 10% to 20% of the weight of the silver micro powder; the average particle size of the flake silver powder is 1.2 to 2.5 μm, and the tap density is 3.5 to 4.5 g / cm³. 3 The silver micropowder has an average particle size of 1.5~3.5μm and a tap density of 4.5~5.5g / cm³. 3 ; The organic carrier is prepared by weighing 10%–30% ethyl cellulose, 6%–13% modified thermosetting acrylic resin, 3%–7% plasticizer, and 55%–75% solvent by weight percentage, mixing them, heating to 70–80°C and stirring for 2–6 hours, and then filtering to obtain the organic carrier. The glass powder is prepared as follows: 55%~60% bismuth trioxide, 8%~15% silicon dioxide, 12%~20% boric acid, 2%~5% aluminum oxide, 1%~3% copper oxide, and 1%~3% zinc oxide are weighed by weight percentage, poured into a ball mill jar, ball-milled, and then discharged and dried at 120~150℃. The dried powder is then heated at 1000~1150℃ for 30~120 minutes. After heating, the solution is water-quenched, ball-milled to refine, dried, and sieved to obtain the glass powder. The glass powder has a particle size of 1~3μm.

2. The conductive silver paste as described in claim 1, characterized in that, The adjuvant is one or more of castor oil, fish oil, lecithin, trimethyl phosphate, Span 85, or polymethacrylamide.

3. The conductive silver paste according to claim 1, characterized in that, The plasticizer is one or more of dibutyl phthalate, dioctyl phthalate, or tributyl citrate; the solvent is one or more of terpineol, butyl carbitol, butyl carbitol acetate, ethylene glycol ethyl ether acetate, ethylene glycol monobutyl ether, tributyl citrate, or cyclohexanone.

4. A method for preparing the conductive silver paste according to any one of claims 1 to 3, characterized in that, The process includes the following steps: weighing the raw materials by weight percentage, mixing and pre-stirring the silver powder, glass powder, additives, low-melting-point inorganic powder, and organic carrier, stirring at 200-500 rpm for 2-6 hours, grinding the dispersed and stirred slurry 3-8 times to confirm that the fineness is ≤10μm, and then filtering to obtain the conductive silver paste.

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