Low-resistance photosensitive silver paste and preparation method and application thereof

Abstract

The invention provides low-resistance photosensitive silver paste as well as a preparation method and application thereof, and relates to the technical field of high-precision intensive wiring laminated chip inductors. The low-resistance photosensitive silver paste is prepared from the following raw materials in parts by weight: alkali-soluble photosensitive resin, a reactive diluent, a photoinitiator, an organic solvent, spherical silver powder and glass powder for the photosensitive silver paste. The particle size D50 of the glass powder for the photosensitive silver paste is 0.8-2 m, the maximum particle size of the glass powder for the photosensitive silver paste is 2-4 m, and the glass powder for the photosensitive silver paste has the characteristics that the particle size is small, the resolution of the photosensitive silver paste is improved, and the sintering resistance is reduced. The prepared low-resistance photosensitive silver paste has the advantages of being high in resolution ratio, free of undercutting, low in resistance, low in shrinkage rate and the like under the condition of high film thickness (the thickness is larger than or equal to 8 m), the requirement for fine wiring of an inner electrode of a laminated chip inductor can be met, and application and expansion of the laminated chip inductor in highly-integrated and miniaturized electronic devices are facilitated.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of electronic paste for multilayer chip inductors (MLCI), in particular to a low-resistance photosensitive silver paste, a preparation method and application thereof. BACKGROUND

[0002] With the accelerated development of the information age, the demand for MLCI in the intelligent automobile, consumer electronics and communication industries is increasing. Nowadays, the electronic information industry has the characteristics of small size, multi-function, high density, high integration and high reliability, which requires the inner electrode wiring of MLCI and other electronic components to be more dense, high resolution and low resistance. At present, the widely used silk screen printing is affected by the mesh number, wire diameter and wiring density, and it is difficult to meet the dense wiring and high resolution of the inner electrode line width and line spacing ≤50 μm of high-end MLCI. Photosensitive silver paste can meet the dense wiring of line width and line spacing of 10-50 μm resolution through printing, soft baking, exposure, development and post-baking processes.

[0003] On the one hand, in order to solve the warping, peeling and cracking and other problems of the photosensitive silver paste of MLCI and the ceramic paste during the lamination and co-firing, a suitable glass powder needs to be added. The glass powder with a suitable expansion coefficient is beneficial to solve such problems. However, the particle size of the glass powder on the market is generally D90≥5 μm, which seriously reduces the resolution of the photosensitive silver paste at a line width ≤25 μm, and increases the resistivity, resulting in that the photosensitive silver paste cannot meet the performance requirements of high precision and low resistance. A suitable glass powder for photosensitive silver paste is crucial to the performance optimization of the photosensitive silver paste.

[0004] On the other hand, the photosensitive silver paste for MLCI has the problems of poor penetration of 365 nm UV light to silver powder in high-silver-containing photosensitive silver paste, and narrow light channel. For high-silver-containing photosensitive silver paste with silver content ≥75%, under the condition of film thickness ≥8 μm, the bottom layer is prone to incomplete curing, causing serious undercut industry technical problems. Due to the reflection of silver powder to UV light, it is easy to cause serious silver line expansion, and there is also the problem of low resolution. Reducing the silver content can indeed effectively solve the problems of undercut and low resolution, but it also brings problems such as serious shrinkage and high resistivity of the photosensitive silver paste after sintering, which seriously affects the electrical performance and yield of the multilayer chip inductor. Therefore, it is of great significance to develop a thick film type photosensitive silver paste material with high silver content, high resolution, no undercut and low resistivity for the high-end development of MLCI electronic components.

[0005] In view of this, the present application is proposed. SUMMARY

[0006] One of the purposes of the present application is to provide a low-resistance photosensitive silver paste, which has the characteristics of high resolution, no undercut, low resistance and low shrinkage under the condition of high film thickness (thickness ≥8 μm).

[0007] The second object of the present application is to provide a preparation method of the low-resistance photosensitive silver paste.

[0008] The third object of the present application is to provide an application of the low-resistance photosensitive silver paste in the preparation of the laminated chip inductor.

[0009] In order to achieve the above objects of the present application, the following technical solutions are adopted: In a first aspect, a low-resistance photosensitive silver paste is provided, and the preparation raw materials of the low-resistance photosensitive silver paste include, by weight fraction: alkali-soluble photosensitive resin, active diluent, photoinitiator, organic solvent, spherical silver powder, and photosensitive silver paste glass powder. The particle size D50 of the photosensitive silver paste glass powder is 0.8-2 µm, and the maximum particle size of the photosensitive silver paste glass powder is 2-4 µm.

[0010] Further, the preparation raw materials of the low-resistance photosensitive silver paste include, by weight fraction: alkali-soluble photosensitive resin 10-30 parts, active diluent 2-8 parts, photoinitiator 0.2-3 parts, organic solvent 1-15 parts, spherical silver powder 60-85 parts, and photosensitive silver paste glass powder 0.5-3 parts.

[0011] Further, the photosensitive silver paste glass powder is a glass powder after ball milling and grading treatment.

[0012] Further, the ball milling medium of the ball milling is a zirconium oxide milling medium ball; the diameter of the zirconium oxide milling medium ball is 1.0-3.0 mm; and the ball-to-material ratio of the ball milling is (0.5-3):1.

[0013] Further, the rotation speed of the ball milling is 50-150 rpm, and the ball milling time is 10-24 h.

[0014] Further, the glass powder includes low-softening-point glass powder and / or high-softening-point glass powder.

[0015] Further, the softening point of the low-softening-point glass powder is 450-650℃.

[0016] Further, the softening point of the high-softening-point glass powder is 700-900℃.

[0017] Further, the expansion coefficient of the glass powder is 5×10 -6 / ℃-15×10 -6 / ℃.

[0018] Further, the low softening point glass powder includes any one of or a combination of at least two of a SiO2-B2O3-based glass powder, a SiO2-B2O3-Li2O-based glass powder, a SiO2-B2O3-Li2O-ZnO-based glass powder, a SiO2-B2O3-K2O-based glass powder, a SiO2-B2O3-K2O-ZnO-based glass powder, or a SiO2-B2O3-Bi2O3-based glass powder.

[0019] Further, the high softening point glass powder includes any one of or a combination of at least two of a SiO2-B2O3-CaO-based glass powder, a SiO2-B2O3-based glass powder, a SiO2-B2O3-TiO2-based glass powder, or a SiO2-Al2O3-Na2O-based glass powder.

[0020] Further, the alkali-soluble photosensitive resin includes an epoxy-based acrylate resin having a high acid value.

[0021] Further, the epoxy-based acrylate resin has an acid value of 25 to 150 mg KOH / g, preferably 50 to 100 mg KOH / g.

[0022] Further, the epoxy-based acrylate resin has a molecular weight of 2,000 to 50,000 g / mol.

[0023] Further, the epoxy-based acrylate resin has a functionality of 2 to 6.

[0024] Further, the epoxy-based acrylate resin includes any one of or a combination of at least two of a phenol novolac epoxy acrylate, a modified phenol novolac epoxy acrylate, an o-methyl phenol novolac epoxy acrylate, or a modified o-methyl phenol novolac epoxy acrylate.

[0025] Further, the reactive diluent includes any one of or a combination of at least two of dipentaerythritol hexaacrylate, dipentaerythritol tetraacrylate, ethoxylated trimethylolpropane triacrylate, trimethylolpropane triacrylate, trimethylolpropane propoxy (3) triacrylate, trimethylolpropane ethoxy (3) triacrylate, 1,6-hexanediol diacrylate, dipropylene glycol diacrylate, tripropylene glycol diacrylate, 30 (ethoxylated) bisphenol A diacrylate, 10 (ethoxylated) bisphenol A diacrylate, 30 (ethoxylated) bisphenol A dimethacrylate, 10 (ethoxylated) bisphenol A dimethacrylate, methoxypolyethylene glycol 600 methacrylate, lauryl acrylate, isobornyl acrylate, isobornyl methacrylate, or methacrylic acid.

[0026] Further, the photoinitiator includes any one of or a combination of at least two of a cleavage-type radical photoinitiator or a hydrogen abstraction-type radical photoinitiator.

[0027] Further, the photoinitiator includes any one of 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butanone, 2-methyl-1-(4-methylthiophenyl)-2-morpholinyl-1-propanone, diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide, phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide, tetraethylthioxanthone, 1-[4-(phenylthio)phenyl]-1,2-octanedione 2-(O-benzoyloxime), 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-ethanone 1-(O-acetyloxime), 2-isopropylthioxanthone, or 2,4-diethylthioxanthone or a combination of at least two thereof.

[0028] Further, the low-resistance photosensitive silver paste further includes a co-initiator.

[0029] Further, a mass ratio of the photoinitiator to the co-initiator is 1:(0~1.5).

[0030] Further, the co-initiator includes any one of 4-dimethylamino benzoic acid ethyl ester, 4,4'-bis(diethylamino)benzophenone, N-tolyl diethanolamine, isopentyl dimethylamino benzoate, isopentyl diethylamino benzoate, 5-mercapto-1-phenyl-1H-tetrazole, triethylamine, or triethanolamine or a combination of at least two thereof.

[0031] Further, the organic solvent includes any one of diethylene glycol methyl ether, diethylene glycol butyl ether acetate, diethylene glycol ethyl ether, diethylene glycol monobutyl ether, diethylene glycol propyl ether, diethylene glycol dibutyl ether, ethylene glycol butyl ether acetate, mixed acid dimethyl ester, alcohol ester-12, terpineol, dipropylene glycol monomethyl ether, dipropylene glycol dimethyl ether, or tetramethylbenzene or a combination of at least two thereof.

[0032] Further, the spherical silver powder includes a spherical silver powder with a D50 of 0.2~5 µm.

[0033] Further, the spherical silver powder includes a main silver powder of 50~100% and a secondary silver powder of 0~50% by mass percentage.

[0034] Further, the main silver powder has a particle size D50 of 1~2.5 µm and the secondary silver powder has a particle size D50 of 0.4~1.0 µm.

[0035] Further, the preparation raw material of the low-resistance photosensitive silver paste further includes an auxiliary agent of 0~3 parts.

[0036] Further, the auxiliary agent includes any one of a dispersing agent, a leveling agent, a defoaming agent, or a thixotropic agent or a combination of at least two thereof.

[0037] In a second aspect, the present application provides a preparation method of the low-resistance photosensitive silver paste according to the first aspect, and the preparation method comprises: mixing and stirring the alkali-soluble photosensitive resin, the active diluent, the photoinitiator and the organic solvent to obtain a glue solution; mixing and centrifugal stirring the spherical silver powder, the photosensitive silver paste glass powder and the glue solution, and grinding to obtain the low-resistance photosensitive silver paste.

[0038] Further, the stirring speed in the preparation of the glue solution is 100-400 rpm, and the stirring time is 2-5 h.

[0039] Further, the centrifugal stirring speed in the preparation of the low-resistance photosensitive silver paste is 5000-10000 rpm, and the centrifugal stirring time is 30-90 s.

[0040] Preferably, the grinding is performed by a three-roll grinder.

[0041] Preferably, the fineness of the low-resistance photosensitive silver paste obtained by the grinding is <8 µm.

[0042] In a third aspect, the present application provides an application of the low-resistance photosensitive silver paste according to the first aspect in the preparation of a multilayer chip inductor.

[0043] Compared with the prior art, the present application has the following beneficial effects: (1) The low-resistance photosensitive silver paste prepared by the present application has the characteristics of small particle size, improved photosensitive silver paste resolution and reduced sintering resistance; (2) The low-resistance photosensitive silver paste prepared by the present application has the characteristics of high resolution, no undercut, low resistance and low shrinkage under high film thickness (thickness ≥8 µm); (3) The low-resistance photosensitive silver paste prepared by the present application can meet the fine wiring requirements of the internal electrode of the multilayer chip inductor, and is conducive to the application expansion of the multilayer chip inductor in highly integrated and miniaturized electronic devices; (4) The preparation method of the low-resistance photosensitive silver paste provided by the present application has the characteristics of simple process steps and small equipment investment, and can meet the needs of industrial large-scale production. BRIEF DESCRIPTION OF DRAWINGS

[0044] In order to more clearly illustrate the technical solutions in the specific embodiments or the prior art of the present application, the drawings needed in the specific embodiments or the prior art description will be briefly introduced below. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0045] Figure 1 Optical image for patterning and imaging on a ceramic substrate for Example 1 of the present invention.

[0046] Figure 2 Cross-sectional optical image for patterning and imaging on a ceramic substrate for Example 1 of the present invention. DETAILED DESCRIPTION

[0047] Unless otherwise defined, scientific and technical terms used in connection with the present application shall have the meanings that are commonly understood by those of ordinary skill in the art. The meaning and scope of the terms should be clear; however, in the event of any latent ambiguity, definitions provided herein take precedent over any dictionary or extrinsic definition. In this application, the use of "or" means "and / or" unless specifically stated otherwise, e.g., "comprising A or B" means "comprising A or B or both". Also, the use of "comprising" or "including" or "having" are not intended to be limiting; other embodiments can include more elements or steps.

[0048] It should be noted that specific details are set forth in the following description in order to provide a thorough understanding of the application. However, the application can be practiced without many of the details described in this description, many of which are well known in the art. Therefore, the particular embodiments described herein are not intended to limit the scope of the application.

[0049] The technical solutions of the present application will be described clearly and completely below in connection with the embodiments. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without making creative efforts fall within the scope of protection of the present application.

[0050] In order to achieve the above-mentioned purposes of the present application, the following technical solutions are adopted: In a first aspect, the present application provides a low-resistance photosensitive silver paste, the preparation raw materials of the low-resistance photosensitive silver paste include, by weight fraction: alkali-soluble photosensitive resin, active diluent, photoinitiator, organic solvent, spherical silver powder, photosensitive silver paste glass powder; wherein the particle size D50 of the photosensitive silver paste glass powder is 0.8-2 μm, and the maximum particle size of the photosensitive silver paste glass powder is 2-4 μm.

[0051] In the present application, by adding a small particle size glass powder in the silver paste, the melting of the silver powder can be effectively promoted, the resistance can be reduced, and the resolution can be improved; and by regulating the selection and collocation of the alkali-soluble photosensitive resin, the active diluent, the photoinitiator, the organic solvent, the spherical silver powder, and the photosensitive silver paste glass powder, and by scientific matching, the resistivity can be effectively reduced, the shrinkage rate can be reduced, the curing depth can be improved, and the reliability and product yield of the photosensitive silver paste and ceramic paste lamination co-firing can be improved. The photosensitive silver paste prepared by the above components has the advantages of high resolution, no undercut, low resistance, low shrinkage rate, etc.

[0052] As an optional implementation, the particle size D50 of the glass powder for the photosensitive silver paste is 0.8-2 µm, and specifically but not limitedly, 2 µm, 1.9 µm, 1.8 µm, 1.7 µm, 1.6 µm, 1.5 µm, 1.4 µm, 1.3 µm, 1.2 µm, 1.1 µm, 1 µm, 0.9 µm, or 0.8 µm, etc.

[0053] As an optional implementation, the maximum particle size of the glass powder for the photosensitive silver paste is 2-4 µm, and specifically but not limitedly, 4 µm, 3.8 µm, 3.6 µm, 3.4 µm, 3.2 µm, 3 µm, 2.8 µm, 2.6 µm, 2.4 µm, 2.2 µm, or 2 µm, etc.

[0054] As an optional implementation, the preparation raw materials of the low-resistance photosensitive silver paste include, by weight fraction, 10-30 parts of alkali-soluble photosensitive resin, 2-8 parts of active diluent, 0.2-3 parts of photoinitiator, 1-15 parts of organic solvent, 60-85 parts of spherical silver powder, and 0.5-3 parts of glass powder for photosensitive silver paste.

[0055] As an optional implementation, in the preparation raw materials of the low-resistance photosensitive silver paste, the content of the alkali-soluble photosensitive resin is 10-30 parts, and specifically but not limitedly, 10 parts, 12 parts, 14 parts, 16 parts, 18 parts, 20 parts, 22 parts, 24 parts, 26 parts, 28 parts, or 30 parts, etc.

[0056] As an optional implementation, in the preparation raw materials of the low-resistance photosensitive silver paste, the content of the active diluent is 2-8 parts, and specifically but not limitedly, 2 parts, 2.5 parts, 3 parts, 3.5 parts, 4 parts, 4.5 parts, 5 parts, 5.5 parts, 6 parts, 6.5 parts, 7 parts, 7.5 parts, or 8 parts, etc.

[0057] As an optional implementation, in the preparation raw materials of the low-resistance photosensitive silver paste, the content of the photoinitiator is 0.2-3 parts, and specifically but not limitedly, 0.2 parts, 0.4 parts, 0.6 parts, 0.8 parts, 1 part, 1.2 parts, 1.4 parts, 1.6 parts, 1.8 parts, 2 parts, 2.2 parts, 2.4 parts, 2.6 parts, 2.8 parts, or 3 parts, etc.

[0058] As an optional implementation, in the preparation raw materials of the low-resistance photosensitive silver paste, the content of the organic solvent is 1-15 parts, and specifically but not limitedly, 1 part, 2 parts, 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, 11 parts, 12 parts, 13 parts, 14 parts, or 15 parts, etc.

[0059] As an optional implementation, the content of the spherical silver powder in the raw material for preparing the low-resistance photosensitive silver paste is 60-85 parts, specifically but not limitedly, 60 parts, 61 parts, 62 parts, 63 parts, 64 parts, 65 parts, 66 parts, 67 parts, 68 parts, 69 parts, 70 parts, 71 parts, 72 parts, 73 parts, 74 parts, 75 parts, 76 parts, 77 parts, 78 parts, 79 parts, 80 parts, 81 parts, 82 parts, 83 parts, 84 parts, or 85 parts, etc.

[0060] As an optional implementation, the content of the photosensitive silver paste glass powder in the raw material for preparing the low-resistance photosensitive silver paste is 0.5-3 parts, specifically but not limitedly, 0.5 parts, 0.7 parts, 0.9 parts, 1.1 parts, 1.3 parts, 1.5 parts, 1.7 parts, 1.9 parts, 2.1 parts, 2.3 parts, 2.5 parts, 2.7 parts, 2.9 parts, 3 parts, etc.

[0061] As an optional implementation, the photosensitive silver paste glass powder is a glass powder processed by ball milling and grading.

[0062] As an optional implementation, the ball milling medium of the ball milling is a zirconium oxide milling medium ball.

[0063] As an optional implementation, the diameter of the zirconium oxide milling medium ball is 1.0-3.0 mm, specifically but not limitedly, 1.0 mm, 1.2 mm, 1.4 mm, 1.6 mm, 1.8 mm, 2.0 mm, 2.2 mm, 2.4 mm, 2.6 mm, 2.8 mm, or 3.0 mm, etc.

[0064] As an optional implementation, the ball-to-material ratio of the ball milling is (0.5-3):1, specifically but not limitedly, 0.5:1, 1:1, 1.5:1, 2:1, 2.5:1, 3:1, etc.

[0065] As an optional implementation, the rotation speed of the ball milling is 50-150 rpm, specifically but not limitedly, 50 rpm, 60 rpm, 70 rpm, 80 rpm, 90 rpm, 100 rpm, 110 rpm, 120 rpm, 130 rpm, 140 rpm, 150 rpm, etc.

[0066] As an optional implementation, the time of the ball milling is 10-24 h, specifically but not limitedly, 10 h, 11 h, 12 h, 13 h, 14 h, 15 h, 16 h, 17 h, 18 h, 19 h, 20 h, 21 h, 22 h, 23 h, or 24 h, etc.

[0067] As an optional embodiment, the glass powder for the photosensitive silver paste is reduced in particle size by ball milling, which is performed using zirconia milling media balls with a diameter of 1.0-3.0 mm for 10-24 h. After ball milling, the glass powder is classified by a cyclone separator and collected at the discharge port. The D50 of the glass powder is 0.8-2 µm, and the maximum particle size is 2-4 µm.

[0068] As an optional embodiment, the glass powder for the photosensitive silver paste comprises low-softening-point glass powder and / or high-softening-point glass powder.

[0069] As an optional embodiment, the mass ratio of the low-softening-point glass powder to the high-softening-point glass powder is (0-100):(100-0). Specifically but not exclusively, the value of “0-100” can be 0, 10, 20, 30, 40, 50, 60, 70, 80, 90, or 100, and the value of “100-0” can be 100, 90, 80, 70, 60, 50, 40, 30, 20, 10, or 0.

[0070] As an optional embodiment, the softening point of the low-softening-point glass powder is 450-650 ℃. Specifically but not exclusively, the softening point can be 450 ℃, 460 ℃, 470 ℃, 480 ℃, 490 ℃, 500 ℃, 510 ℃, 520 ℃, 530 ℃, 540 ℃, 550 ℃, 560 ℃, 570 ℃, 580 ℃, 590 ℃, 600 ℃, 610 ℃, 620 ℃, 630 ℃, 640 ℃, or 650 ℃.

[0071] As an optional embodiment, the softening point of the high-softening-point glass powder is 700-900 ℃. Specifically but not exclusively, the softening point can be 700 ℃, 720 ℃, 740 ℃, 760 ℃, 780 ℃, 800 ℃, 820 ℃, 840 ℃, 860 ℃, 880 ℃, or 900 ℃.

[0072] As an optional embodiment, the coefficient of thermal expansion of the glass powder is 5×10 -6 / ℃-15×10 -6 / ℃. Specifically but not exclusively, the coefficient of thermal expansion can be 5×10 -6 / ℃, 6×10 -6 / ℃, 7×10 -6 / ℃, 8×10 -6 / ℃, 9×10 -6 / ℃, 10×10 -6 / ℃, 11×10 -6 / ℃, 12×10 -6 / ℃, 13×10 -6 / ℃, 14×10 -6 / ℃, 15×10 -6 / ℃, or the like.

[0073] As an optional embodiment, the low softening point glass powder includes any one of SiO2-B2O3-based glass powder, SiO2-B2O3-Li2O-based glass powder, SiO2-B2O3-Li2O-ZnO-based glass powder, SiO2-B2O3-K2O-based glass powder, SiO2-B2O3-K2O-ZnO-based glass powder, or SiO2-B2O3-Bi2O3-based glass powder or a combination of at least two thereof.

[0074] As an optional embodiment, the high softening point glass powder includes any one of SiO2-B2O3-CaO-based glass powder, SiO2-B2O3-Al2O3-based glass powder, SiO2-B2O3-TiO2-based glass powder, or SiO2-Al2O3-Na2O-based glass powder or a combination of at least two thereof.

[0075] As an optional embodiment, the alkali-soluble photosensitive resin includes an epoxy-based acrylate resin with a high acid value.

[0076] As an optional embodiment, the acid value of the epoxy-based acrylate resin is 25-150 mg KOH / g, specifically but not limitedly, 25 mg KOH / g, 45 mg KOH / g, 65 mg KOH / g, 85 mg KOH / g, 105 mg KOH / g, 125 mg KOH / g, 145 mg KOH / g, or 150 mg KOH / g, etc.

[0077] As a preferred embodiment, the acid value of the epoxy-based acrylate resin is 50-100 mg KOH / g.

[0078] It should be noted that the performance of the photosensitive silver paste is greatly affected by the photosensitive resin, and a relatively high acid value resin can effectively improve the alkali solubility and improve the development difference.

[0079] As an optional embodiment, the epoxy acrylate resin has a molecular weight of 2000 to 50000 g / mol, specifically but not limitedly, 2000 g / mol, 4000 g / mol, 6000 g / mol, 8000 g / mol, 10000 g / mol, 12000 g / mol, 14000 g / mol, 16000 g / mol, 18000 g / mol, 20000 g / mol, 22000 g / mol, 24000 g / mol, 26000 g / mol, 28000 g / mol, 30000 g / mol, 32000 g / mol, 34000 g / mol, 36000 g / mol, 38000 g / mol, 40000 g / mol, 42000 g / mol, 44000 g / mol, 46000 g / mol, 48000 g / mol, or 50000 g / mol, etc.

[0080] As an optional embodiment, the epoxy acrylate resin has a functionality of 2 to 6, specifically but not limitedly, a functionality of 2, 3, 4, 5, or 6.

[0081] As an optional embodiment, the epoxy acrylate resin comprises any one or a combination of at least two of a phenol novolac epoxy acrylate, a modified phenol novolac epoxy acrylate, an o-methyl phenol novolac epoxy acrylate, or a modified o-methyl phenol novolac epoxy acrylate.

[0082] As an optional embodiment, the reactive diluent comprises any one or a combination of at least two of dipentaerythritol hexaacrylate, dipentaerythritol tetraacrylate, ethoxylated trimethylolpropane triacrylate, trimethylolpropane triacrylate, trimethylolpropane propoxy (3) triacrylate, trimethylolpropane ethoxy (3) triacrylate, 1,6-hexanediol diacrylate, dipropylene glycol diacrylate, tripropylene glycol diacrylate, 30 (ethoxylated) bisphenol A diacrylate, 10 (ethoxylated) bisphenol A diacrylate, 30 (ethoxylated) bisphenol A dimethacrylate, 10 (ethoxylated) bisphenol A dimethacrylate, methoxypolyethylene glycol 600 methacrylate, lauryl acrylate, isobornyl acrylate, isobornyl methacrylate, or methacrylic acid.

[0083] As an optional embodiment, the photoinitiator comprises any one or a combination of at least two of a cleavage-type radical photoinitiator or a hydrogen abstraction-type radical photoinitiator.

[0084] As an optional embodiment, the photoinitiator includes any one of 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butanone, 2-methyl-1-(4-methylthiophenyl)-2-morpholino-1-propanone, diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide, phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, tetraethyl Michler's ketone, 1-[4-(phenylthio)phenyl]-1,2-octanedione 2-(O-benzoyl oxime), 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-ethanone 1-(O-acetyl oxime), 2-isopropylthioxanthone or 2,4-diethylthiazolone, or a combination of at least two thereof.

[0085] As an optional embodiment, the raw materials for preparing the low-resistance photosensitive silver paste further include a co-initiator (the co-initiator can be used in combination with the photoinitiator).

[0086] As an optional embodiment, the mass ratio of the photoinitiator to the co-initiator is 1:(0~1.5), specifically but not limited to 1:0 (representing no co-initiator is added), 1:0.1, 1:0.2, 1:0.3, 1:0.4, 1:0.5, 1:0.6, 1:0.7, 1:0.8, 1:0.9, 1:1, 1:1.1, 1:1.2, 1:1.3, 1:1.4 or 1:1.5, etc.

[0087] As an optional embodiment, the co-initiator includes any one or a combination of at least two of ethyl 4-dimethylaminobenzoate, 4,4'-bis(diethylamino)benzophenone, N-tolyldiethanolamine, isopentyl dimethylaminobenzoate, isopentyl diethylaminobenzoate, 5-mercapto-1-phenyl-1H-tetrazole, triethylamine or triethanolamine.

[0088] It should be noted that the photoinitiator needs to be selected from any one or a combination of at least two with strong absorption at a wavelength of 365 nm, which can effectively improve UV curing efficiency, reduce undercutting problems, and ensure product yield and stability.

[0089] As an optional embodiment, the organic solvent includes any one of diethylene glycol methyl ether, diethylene glycol butyl ether acetate, diethylene glycol ethyl ether, diethylene glycol monobutyl ether, diethylene glycol propyl ether, diethylene glycol dibutyl ether, ethylene glycol butyl ether acetate, mixed acid dimethyl ester, alcohol ester-12, terpineol, dipropylene glycol monomethyl ether, dipropylene glycol dimethyl ether or tetramethylbenzene, or a combination of at least two thereof.

[0090] As an optional implementation, the spherical silver powder includes a spherical silver powder with a D50 of 0.2-5 µm, which can be specifically but not limitedly selected from 0.2 µm, 0.4 µm, 0.6 µm, 0.8 µm, 1.0 µm, 1.2 µm, 1.4 µm, 1.6 µm, 1.8 µm, 2.0 µm, 2.2 µm, 2.4 µm, 2.6 µm, 2.8 µm, 3.0 µm, 3.2 µm, 3.4 µm, 3.6 µm, 3.8 µm, 4.0 µm, 4.2 µm, 4.4 µm, 4.6 µm, 4.8 µm, or 5.0 µm, etc.

[0091] As an optional implementation, the spherical silver powder includes the main silver powder 50-100% and the auxiliary silver powder 0-50% by mass percentage.

[0092] As an optional implementation, the content of the main silver powder is 50-100% in the total mass of the spherical silver powder, which can be specifically but not limitedly selected from 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, or 100%, etc.

[0093] As an optional implementation, the content of the auxiliary silver powder is 0-50% in the total mass of the spherical silver powder, which can be specifically but not limitedly selected from 0%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, or 50%, etc.

[0094] As an optional implementation, the particle size D50 of the main silver powder is 1-2.5 µm, which can be specifically but not limitedly selected from 1.0 µm, 1.1 µm, 1.2 µm, 1.3 µm, 1.4 µm, 1.5 µm, 1.6 µm, 1.7 µm, 1.8 µm, 1.9 µm, 2.0 µm, 2.1 µm, 2.2 µm, 2.3 µm, 2.4 µm, or 2.5 µm, etc.

[0095] As an optional implementation, the particle size D50 of the auxiliary silver powder is 0.4-1.0 µm, which can be specifically but not limitedly selected from 0.4 µm, 0.45 µm, 0.5 µm, 0.55 µm, 0.6 µm, 0.65 µm, 0.7 µm, 0.75 µm, 0.8 µm, 0.85 µm, 0.9 µm, 0.95 µm, 0.99 µm, 1 µm, etc.

[0096] It should be noted that the composition and particle size distribution of the spherical silver powder can seriously affect the imaging effect of the photosensitive silver paste and the resistivity after sintering.

[0097] As an optional embodiment, the preparation raw material of the low-resistance photosensitive silver paste further comprises: an auxiliary agent 0-3 parts, specifically but not limitedly, 0 parts, 0.2 parts, 0.4 parts, 0.6 parts, 0.8 parts, 1.0 parts, 1.2 parts, 1.4 parts, 1.6 parts, 1.8 parts, 2.0 parts, 2.2 parts, 2.4 parts, 2.6 parts, 2.8 parts, or 3.0 parts, etc.

[0098] As an optional embodiment, the auxiliary agent comprises any one or a combination of at least two of a dispersing agent, a leveling agent, a defoaming agent, or a thixotropic agent.

[0099] In a second aspect, the present application provides a preparation method of the low-resistance photosensitive silver paste according to the first aspect, the preparation method of the low-resistance photosensitive silver paste comprising: mixing and stirring the alkali-soluble photosensitive resin, the active diluent, the photoinitiator, and the organic solvent to obtain a glue solution; mixing and centrifugal stirring the spherical silver powder, the photosensitive silver paste glass powder, and the glue solution, and grinding to obtain the low-resistance photosensitive silver paste.

[0100] As an optional embodiment, the preparation method of the low-resistance photosensitive silver paste specifically comprises: mixing and sufficiently stirring the alkali-soluble photosensitive resin, the active diluent, the photoinitiator, and the organic solvent to form a transparent glue solution with the solid substances fully dissolved; mixing and centrifugal stirring the spherical silver powder, the photosensitive silver paste glass powder, the auxiliary agent, and the transparent glue solution after dissolution, and grinding by a three-roll grinder to obtain the photosensitive silver paste.

[0101] As an optional embodiment, the stirring speed in preparing the glue solution is 100-400 rpm, specifically but not limitedly, 100 rpm, 120 rpm, 140 rpm, 160 rpm, 180 rpm, 200 rpm, 220 rpm, 240 rpm, 260 rpm, 280 rpm, 300 rpm, 320 rpm, 340 rpm, 360 rpm, 380 rpm, or 400 rpm, etc., and the stirring time is 2-5 h, specifically but not limitedly, 2.0 h, 2.2 h, 2.4 h, 2.6 h, 2.8 h, 3.0 h, 3.2 h, 3.4 h, 3.6 h, 3.8 h, 4.0 h, 4.2 h, 4.4 h, 4.6 h, 4.8 h, or 5.0 h, etc.

[0102] As an optional embodiment, the rotation speed of the centrifugal stirring in preparing the low-resistance photosensitive silver paste is 5000-10000 rpm, and specifically but not limitedly, 5000 rpm, 5500 rpm, 6000 rpm, 6500 rpm, 7000 rpm, 7500 rpm, 8000 rpm, 8500 rpm, 9000 rpm, 9500 rpm or 10000 rpm, etc. can be selected, and the centrifugal stirring time is 30-90 s, and specifically but not limitedly, 30 s, 35 s, 40 s, 45 s, 50 s, 55 s, 60 s, 65 s, 70 s, 75 s, 80 s, 85 s or 90 s, etc. can be selected.

[0103] As an optional embodiment, the grinding is performed by using a three-roll grinder.

[0104] As an optional embodiment, the fineness of the low-resistance photosensitive silver paste obtained by the grinding is <8 µm.

[0105] In a third aspect, the present application provides a use of the low-resistance photosensitive silver paste according to the first aspect in preparing a multilayer chip inductor.

[0106] In the present application, a multilayer chip inductor is also provided, which is produced by using the photosensitive silver paste according to any one of the preceding embodiments. For example, the surface of a ceramic paste film is printed with the photosensitive silver paste film in the preparation process of the multilayer chip inductor. The multilayer chip inductor formed by laminating the ceramic paste film printed with the photosensitive silver paste film has the advantages of low resistance, high resolution, high yield, production efficiency, etc.

[0107] The present application is further illustrated by the following examples. Unless otherwise specified, the materials in the examples are prepared according to the existing methods or directly purchased from the market.

[0108] Preparation Example 1 The present preparation example provides a glass powder for photosensitive silver paste, which is prepared by the following steps: SiO2-B2O3 is physically mixed at a mass ratio of 8:2, then loaded into a crucible and placed in a resistance furnace at 1200±100℃ for melting for 80 min. After melting, the molten glass is quickly introduced into cold deionized water for quenching. After cooling to room temperature, it is subjected to airflow crushing, and finally ball milling is performed using a ball mill. After ball milling, classification is performed by a cyclone separator, and the product is collected at the discharge port, thereby obtaining SiO2-B2O3 glass powder. The ball milling medium is a zirconium oxide milling medium ball; the diameter of the zirconium oxide milling medium ball is 1-3 mm; the ball-to-material ratio of the ball milling is 2:1; the rotation speed of the ball milling is 100 rpm, and the ball milling time is 20 h. The particle size D50 of the SiO2-B2O3 glass powder obtained by ball milling is 1.45 µm, and the maximum particle size is 3.75 µm; the softening point of the SiO2-B2O3 glass powder is 535 ℃, and the expansion coefficient is 6.8×10 -6 / ℃.

[0109] Preparation Example 2 The present preparation example provides a glass powder for a photosensitive silver paste, which is prepared by the following steps: SiO2-B2O3-Bi2O3 is physically mixed at a mass ratio of 4:1:5, then is loaded into a crucible and placed in a resistance furnace at 1200±100 ℃ for 80 min, after the melting is completed, the molten glass is rapidly introduced into cold deionized water for quenching, after cooling to room temperature, air flow crushing is performed, and finally a ball mill is used for ball milling, after the ball milling is completed, classification is performed by a cyclone separator, and collection is performed at the discharge port, thereby obtaining a SiO2-B2O3-Bi2O3 glass powder. The ball milling medium is a zirconium oxide milling medium ball; the diameter of the zirconium oxide milling medium ball is 1-3 mm; the ball-to-material ratio of the ball milling is 2:1; the rotation speed of the ball milling is 100 rpm, and the ball milling time is 20 h. The particle size D50 of the SiO2-B2O3-Bi2O3 glass powder obtained by ball milling is 1.54 µm, and the maximum particle size is 3.6 µm; the softening point of the SiO2-B2O3-Bi2O3 glass powder is 520 ℃, and the expansion coefficient is 8.9×10 -6 / ℃.

[0110] Comparative Preparation Example 1 The present comparative preparation example provides a SiO2-B2O3 glass powder, which is prepared by the following steps: SiO2-B2O3 is physically mixed at a mass ratio of 8:2, then is loaded into a crucible and placed in a resistance furnace at 1200±100 ℃ for melting for 80 min, after the melting is completed, the molten glass is rapidly introduced into cold deionized water for quenching, after cooling to room temperature, air flow crushing is performed, thereby obtaining a SiO2-B2O3 glass powder. The particle size D50 of the SiO2-B2O3 glass powder without ball milling is 2.5 µm, and the maximum particle size is 6.13 µm; the softening point of the SiO2-B2O3 glass powder is 545 ℃, and the expansion coefficient is 6.4×10 -6 / ℃.

[0111] Comparative Preparation Example 2 The present comparative preparation example provides a SiO2-B2O3-Bi2O3-based glass powder prepared by the following steps: SiO2-B2O3-Bi2O3was physically mixed at a mass ratio of 4:1.5, then was loaded into a crucible and placed in a resistance furnace at 1200±100℃ for melting for 80 min. After the melting was completed, the molten glass was rapidly introduced into cold deionized water for quenching. After cooling to room temperature, the glass was subjected to air flow crushing, and then was ball milled. After the ball milling was completed, the glass was classified by a cyclone separator, and was collected at the discharge port to obtain a SiO2-B2O3-Bi2O3-based glass powder. The SiO2-B2O3-Bi2O3-based glass powder not subjected to ball milling has a particle size D50 of 2.6 µm and a maximum particle size of 5.9 µm. The SiO2-B2O3-Bi2O3-based glass powder has a softening point of 525℃ and an expansion coefficient of 8.4×10 -6 / ℃.

[0112] Comparative Preparation Example 3 The present comparative preparation example provides a SiO2-B2O3-Al2O3-based glass powder prepared by the following steps: SiO2-B2O3-Al2O3was physically mixed at a mass ratio of 6:2:2, then was loaded into a crucible and placed in a resistance furnace at 1200±100℃ for melting for 80 min. After the melting was completed, the molten glass was rapidly introduced into cold deionized water for quenching. After cooling to room temperature, the glass was subjected to air flow crushing, and then was ball milled. After the ball milling was completed, the glass was classified by a cyclone separator, and was collected at the discharge port to obtain a SiO2-B2O3-Al2O3-based glass powder. The ball milling medium was a zirconia medium ball. The diameter of the zirconia medium ball was 1-3 mm. The ball-to-material ratio of the ball milling was 2:1. The rotation speed of the ball milling was 100 rpm, and the ball milling time was 20 h. The SiO2-B2O3-Al2O3-based glass powder not subjected to ball milling has a particle size D50 of 1.8 µm and a maximum particle size of 3.85 µm. The SiO2-B2O3-Al2O3-based glass powder has a softening point of 720℃ and an expansion coefficient of 6.5×10 -6 / ℃.

[0113] Example 1 The present example provides a low-resistance photosensitive silver paste prepared by the following steps: (1) Take modified o-methyl phenolic epoxy acrylate (acid value is 60 mg KOH / g, molecular weight is 8000 g / mol, functionality is 2) 12 parts, 10 (ethoxy) bisphenol A diacrylate 1 part, isobornyl acrylate 1 part, 2-isopropyl thioxanthone 0.1 part, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl) butanone 0.4 part, diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide 0.3 part, 5-mercapto-1-phenyl-1H-tetrazole 0.2 part, mixed acid dimethyl ester 1 part, diethylene glycol butyl ether acetate 1 part, alcohol ester twelve 1 part, and stir at room temperature for 3 h to make the solid substances fully dissolved to form a transparent glue liquid; (2) Take BYK-330 0.5 parts, oleic acid 0.5 parts, SiO2-B2O3 system glass powder after ball milling and grading provided by Preparation Example 1 0.5 parts, SiO2-B2O3-Bi2O3 system glass powder after ball milling and grading provided by Preparation Example 2 0.5 parts, spherical silver powder (D50 is 1.5 µm) 70 parts, spherical silver powder (D50 is 2 µm) 10 parts, and mix them with the transparent glue liquid obtained in (1) at room temperature and centrifugal stir at 8000 rpm for 60 s. After fully mixing, pass through a three-roll mill to a fineness of <8 µm to obtain a low-resistance photosensitive silver paste.

[0114] Example 2 The present example provides a low-resistance photosensitive silver paste prepared by the following steps: (1) Take modified o-methyl phenolic epoxy acrylate (acid value is 60 mg KOH / g, molecular weight is 8000 g / mol, functionality is 2) 12 parts, bisquintacryl hexaacrylate 1 part, 1,6-hexanediol diacrylate 1 part, 2-isopropyl thioxanthone 0.5 part, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl) butanone 0.5 part, mixed acid dimethyl ester 1 part, diethylene glycol butyl ether acetate 1 part, alcohol ester twelve 1 part, and stir at room temperature for 3 h to make the solid substances fully dissolved to form a transparent glue liquid; (2) Take BYK-330 0.5 parts, oleic acid 0.5 parts, SiO2-B2O3 system glass powder after ball milling and grading provided by Preparation Example 1 0.5 parts, SiO2-B2O3-Bi2O3 system glass powder after ball milling and grading provided by Preparation Example 2 0.5 parts, spherical silver powder (D50 is 1.5 µm) 40 parts, spherical silver powder (D50 is 2 µm) 40 parts, and mix them with the transparent glue liquid obtained in (1) at room temperature and centrifugal stir at 8000 rpm for 60 s. After fully mixing, pass through a three-roll mill to a fineness of <8 µm to obtain a low-resistance photosensitive silver paste.

[0115] Example 3 The present example provides a low-resistance photosensitive silver paste prepared by the following steps: (1) Take modified o-methyl phenolic epoxy acrylate (acid value is 60 mg KOH / g, molecular weight is 8000 g / mol, functionality is 2) 12 parts, dipentaerythritol hexaacrylate 1 part, 1,6-hexanediol diacrylate 1 part, 2-isopropyl thioxanthone 0.5 part, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl) butanone 0.5 part, mixed acid dimethyl ester 1 part, diethylene glycol butyl ether acetate 1 part, alcohol ester twelve 1 part, and stir at room temperature for 3 h at a speed of 200 rpm to fully dissolve the solid substances to form a transparent glue solution; (2) Take BYK-330 0.5 parts, oleic acid 0.5 parts, SiO2-B2O3-based glass powder after ball milling and grading provided in Preparation Example 1 0.5 parts, SiO2-B2O3-Bi2O3-based glass powder after ball milling and grading provided in Preparation Example 2 0.5 parts, spherical silver powder (D50 is 1.5 µm) 70 parts, and spherical silver powder (D50 is 2 µm) 10 parts, and fully mix with the transparent glue solution obtained in (1) at room temperature and centrifugal stir at a speed of 8000 rpm for 60 s. After fully mixing, pass through a three-roll mill to a fineness of <8 µm to obtain a low-resistance photosensitive silver paste.

[0116] Example 4 The present example provides a low-resistance photosensitive silver paste prepared by the following steps: (1) Take modified o-methyl phenolic epoxy acrylate (acid value is 60 mg KOH / g, molecular weight is 8000 g / mol, functionality is 2) 12 parts, dipentaerythritol hexaacrylate 1 part, 1,6-hexanediol diacrylate 1 part, 2-isopropyl thioxanthone 0.5 part, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl) butanone 0.5 part, mixed acid dimethyl ester 1 part, diethylene glycol butyl ether acetate 1 part, alcohol ester twelve 1 part, and stir at room temperature for 3 h at a speed of 200 rpm to fully dissolve the solid substances to form a transparent glue solution; (2) Take BYK-330 0.5 parts, oleic acid 0.5 parts, SiO2-B2O3 system glass powder after ball milling and grading provided by Preparation Example 1 0.5 parts, SiO2-B2O3-Bi2O3 system glass powder after ball milling and grading provided by Preparation Example 2 0.5 parts, spherical silver powder (D50 is 1.5 µm) 60 parts, spherical silver powder (D50 is 2 µm) 10 parts, spherical silver powder (D50 is 0.5 µm) 10 parts, and the transparent glue solution obtained in (1) are fully mixed at room temperature and centrifugal stirring at a speed of 8000 rpm for 60 s, after fully mixing, grinding through a three-roll mill to a fineness of <8 µm, to obtain a low-resistance photosensitive silver paste.

[0117] Example 5 This example provides a low-resistance photosensitive silver paste, which is prepared by the following steps: (1) Take modified o-methyl phenolic epoxy acrylate (acid value is 60 mg KOH / g, molecular weight is 8000 g / mol, functionality is 2) 12 parts, 10(ethoxy) bisphenol A diacrylate 1 part, isobornyl acrylate 1 part, 2-isopropyl thioxanthone 0.5 part, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl) butanone 0.5 part, mixed acid dimethyl ester 1 part, diethylene glycol butyl ether acetate 1 part, alcohol ester twelve 1 part, and fully stir and dissolve at room temperature at a speed of 200 rpm for 3 h, so that the solid substances are fully dissolved to form a transparent glue solution; (2) Take BYK-330 0.5 parts, oleic acid 0.5 parts, SiO2-B2O3 system glass powder after ball milling and grading provided by Preparation Example 1 0.5 parts, SiO2-B2O3-Bi2O3 system glass powder after ball milling and grading provided by Preparation Example 2 0.5 parts, spherical silver powder (D50 is 1.5 µm) 70 parts, and spherical silver powder (D50 is 2 µm) 10 parts, and the transparent glue solution obtained in (1) are fully mixed at room temperature and centrifugal stirring at a speed of 8000 rpm for 60 s, after fully mixing, grinding through a three-roll mill to a fineness of <8 µm, to obtain a low-resistance photosensitive silver paste.

[0118] Example 6 This example provides a low-resistance photosensitive silver paste, which is prepared by the following steps: (1) Take modified o-methyl phenolic epoxy acrylate (acid value is 60 mg KOH / g, molecular weight is 8000 g / mol, functionality is 2) 12 parts, 10 (ethoxyl) bisphenol A diacrylate 1 part, isobornyl acrylate 1 part, 2-isopropyl thioxanthone 0.1 part, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl) butanone 0.4 part, diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide 0.3 part, 4-dimethylamino benzoic acid ethyl ester 0.2 part, mixed acid dimethyl ester 1 part, diethylene glycol butyl ether acetate 1 part, alcohol ester twelve 1 part, and fully stir and dissolve at room temperature for 3 h at a rotation speed of 200 rpm, so that the solid substances are fully dissolved to form a transparent glue liquid; (2) Take BYK-330 0.5 parts, oleic acid 0.5 parts, ball-milled and graded SiO2-B2O3-based glass powder provided in Preparation Example 1 0.5 parts, ball-milled and graded SiO2-B2O3-Bi2O3-based glass powder provided in Preparation Example 2 0.5 parts, spherical silver powder (D50 is 1.5 µm) 70 parts, and spherical silver powder (D50 is 2 µm) 10 parts, and fully mix with the transparent glue liquid obtained in (1) at room temperature and centrifugal stir at a rotation speed of 8000 rpm for 60 s, after fully mixing, pass through a three-roll mill to a fineness of <8 µm, to obtain a low-resistance photosensitive silver paste.

[0119] Example 7 The present example provides a low-resistance photosensitive silver paste, which is prepared by the following steps: (1) Take modified o-methyl phenolic epoxy acrylate (acid value is 60 mg KOH / g, molecular weight is 8000 g / mol, functionality is 2) 12 parts, 10 (ethoxyl) bisphenol A diacrylate 1 part, isobornyl acrylate 1 part, 2-isopropyl thioxanthone 0.5 parts, 1-[4-(phenylthio)phenyl]-1,2-octanedione 2-(O-benzoyl oxime) 0.5 parts, mixed acid dimethyl ester 1 part, diethylene glycol butyl ether acetate 1 part, alcohol ester twelve 1 part, and fully stir and dissolve at room temperature for 3 h at a rotation speed of 200 rpm, so that the solid substances are fully dissolved to form a transparent glue liquid; (2) Take BYK-330 0.5 parts, oleic acid 0.5 parts, ball-milled and graded SiO2-B2O3-based glass powder provided in Preparation Example 1 0.5 parts, ball-milled and graded SiO2-B2O3-Bi2O3-based glass powder provided in Preparation Example 2 0.5 parts, spherical silver powder (D50 is 1.5 µm) 70 parts, and spherical silver powder (D50 is 2 µm) 10 parts, and fully mix with the transparent glue liquid obtained in (1) at room temperature and centrifugal stir at a rotation speed of 8000 rpm for 60 s, after fully mixing, pass through a three-roll mill to a fineness of <8 µm, to obtain a low-resistance photosensitive silver paste.

[0120] Example 8 The present example provides a low-resistance photosensitive silver paste prepared by the following steps: (1) Take modified o-methyl phenolic epoxy acrylate (acid value is 60 mg KOH / g, molecular weight is 8000 g / mol, functionality is 2) 12 parts, 10 (ethoxy) bisphenol A diacrylate 1 part, isobornyl acrylate 1 part, 2-isopropyl thioxanthone 0.5 part, diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide 0.5 part, mixed acid dimethyl ester 1 part, diethylene glycol butyl ether acetate 1 part, alcohol ester twelve 1 part, and stir at room temperature for 3 h at a speed of 200 rpm to fully dissolve the solid substances and form a transparent glue solution; (2) Take BYK-330 0.5 parts, oleic acid 0.5 parts, SiO2-B2O3 system glass powder provided by preparation example 1 after ball milling and grading 0.5 parts, SiO2-B2O3-Bi2O3 system glass powder provided by preparation example 2 after ball milling and grading 0.5 parts, spherical silver powder (D50 is 1.5 µm) 70 parts, and spherical silver powder (D50 is 2 µm) 10 parts, and fully mix them with the transparent glue solution obtained in (1) at room temperature and centrifugal stir at a speed of 8000 rpm for 60 s. After fully mixing, pass through a three-roll mill to a fineness of <8 µm to obtain a low-resistance photosensitive silver paste.

[0121] Comparative Example 1 The present example provides a low-resistance photosensitive silver paste prepared by the following steps: (1) Take modified o-methyl phenolic epoxy acrylate (acid value is 60 mg KOH / g, molecular weight is 8000 g / mol, functionality is 2) 12 parts, 10 (ethoxy) bisphenol A diacrylate 1 part, isobornyl acrylate 1 part, 2-isopropyl thioxanthone 0.5 part, diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide 0.5 part, mixed acid dimethyl ester 1 part, diethylene glycol butyl ether acetate 1 part, alcohol ester twelve 1 part, and stir at room temperature for 3 h at a speed of 200 rpm to fully dissolve the solid substances and form a transparent glue solution; (2) Take BYK-330 0.5 parts, oleic acid 0.5 parts, SiO2-B2O3 system glass powder provided by preparation example 1 after ball milling and grading 0.5 parts, SiO2-B2O3-Bi2O3 system glass powder provided by preparation example 2 after ball milling and grading 0.5 parts, spherical silver powder (D50 is 1.5 µm) 70 parts, and spherical silver powder (D50 is 2 µm) 10 parts, and fully mix them with the transparent glue solution obtained in (1) at room temperature and centrifugal stir at a speed of 8000 rpm for 60 s. After fully mixing, pass through a three-roll mill to a fineness of <8 µm to obtain a low-resistance photosensitive silver paste.

[0122] Comparative Example 2 The present comparative example provides a photosensitive silver paste prepared by the following steps: (1) Take modified o-methyl phenolic epoxy acrylate (acid value is 60 mg KOH / g, molecular weight is 8000 g / mol, functionality is 2) 12 parts, dipentaerythritol hexaacrylate 1 part, 1,6-hexanediol diacrylate 1 part, 2-isopropyl thioxanthone 0.5 part, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl) butanone 0.5 part, mixed acid dimethyl ester 1 part, diethylene glycol butyl ether acetate 1 part, alcohol ester twelve 1 part, and fully stir and dissolve at room temperature for 3 h at a rotation speed of 200 rpm, so that the solid substances are fully dissolved to form a transparent glue solution; (2) Take BYK-330 0.5 parts, oleic acid 0.5 parts, SiO2-B2O3-Al2O3 system glass powder provided by Comparative Preparation Example 3 after ball milling and grading 1 part, spherical silver powder (D50 is 1.5 µm) 70 parts and spherical silver powder (D50 is 2 µm) 10 parts, and fully mix with the transparent glue solution obtained in (1) at room temperature and centrifugal stir at a rotation speed of 8000 rpm for 60 s, after fully mixing, pass through a three-roll mill to a fineness of <8 µm to obtain a photosensitive silver paste.

[0123] Comparative Example 3 The present comparative example provides a photosensitive silver paste prepared by the following steps: (1) Take modified o-methyl phenolic epoxy acrylate (acid value is 60 mg KOH / g, molecular weight is 8000 g / mol, functionality is 2) 18 parts, dipentaerythritol hexaacrylate 2 parts, 1,6-hexanediol diacrylate 3 parts, 2-isopropyl thioxanthone 1 part, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl) butanone 1 part, mixed acid dimethyl ester 1 part, diethylene glycol butyl ether acetate 1 part, alcohol ester twelve 1 part, and fully stir and dissolve at room temperature for 3 h at a rotation speed of 200 rpm, so that the solid substances are fully dissolved to form a transparent glue solution; (2) Take BYK-330 0.5 parts, oleic acid 0.5 parts, SiO2-B2O3 system glass powder provided by Preparation Example 1 after ball milling and grading 0.5 parts, SiO2-B2O3-Bi2O3 system glass powder provided by Preparation Example 2 after ball milling and grading 0.5 parts, spherical silver powder (D50 is 1.5 µm) 40 parts and D50 is 1 µm spherical silver powder 30 parts, and fully mix with the transparent glue solution obtained in (1) at room temperature and centrifugal stir at a rotation speed of 8000 rpm for 60 s, after fully mixing, pass through a three-roll mill to a fineness of <8 µm to obtain a photosensitive silver paste.

[0124] Comparative Example 4 The comparative example provides a photosensitive silver paste prepared by the following steps: (1) Take modified o-methyl phenolic epoxy acrylate (acid value is 60 mg KOH / g, molecular weight is 8000 g / mol, functionality is 2) 12 parts, dipentaerythritol hexaacrylate 1 part, 1,6-hexanediol diacrylate 1 part, 2-isopropyl thioxanthone 0.5 part, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl) butanone 0.5 part, mixed acid dimethyl ester 1 part, diethylene glycol butyl ether acetate 1 part, alcohol ester twelve 1 part, and stir at room temperature for 3 h at a speed of 200 rpm to fully dissolve the solid substances to form a transparent glue solution; (2) Take BYK-330 0.5 parts, oleic acid 0.5 parts, SiO2-B2O3 system glass powder after ball milling and grading provided by preparation example 1 0.5 parts, SiO2-B2O3-Bi2O3 system glass powder after ball milling and grading provided by preparation example 2 0.5 parts, spherical silver powder (D50 is 1.5 µm) 40 parts, and spherical silver powder (D50 is 0.5 µm) 40 parts, and fully mix with the transparent glue solution obtained in (1) at room temperature and centrifugal stir at a speed of 8000 rpm for 60 s, after fully mixing, pass through a three-roll mill to a fineness of <8 µm to obtain a photosensitive silver paste.

[0125] Comparative example 5 The comparative example provides a photosensitive silver paste prepared by the following steps: (1) Take modified o-methyl phenolic epoxy acrylate (acid value is 60 mg KOH / g, molecular weight is 8000 g / mol, functionality is 2) 12 parts, dipentaerythritol hexaacrylate 1 part, 1,6-hexanediol diacrylate 1 part, 2-isopropyl thioxanthone 0.5 part, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl) butanone 0.5 part, mixed acid dimethyl ester 1 part, diethylene glycol butyl ether acetate 1 part, alcohol ester twelve 1 part, and stir at room temperature for 3 h at a speed of 200 rpm to fully dissolve the solid substances to form a transparent glue solution; (2) Take BYK-330 0.5 parts, oleic acid 0.5 parts, SiO2-B2O3 system glass powder after ball milling and grading provided by preparation example 1 0.5 parts, SiO2-B2O3-Bi2O3 system glass powder after ball milling and grading provided by preparation example 2 0.5 parts, spherical silver powder (D50 is 1.5 µm) 40 parts, and spherical silver powder (D50 is 0.5 µm) 40 parts, and fully mix with the transparent glue solution obtained in (1) at room temperature and centrifugal stir at a speed of 8000 rpm for 60 s, after fully mixing, pass through a three-roll mill to a fineness of <8 µm to obtain a photosensitive silver paste.

[0126] Test example 1 Test samples: the low-resistance photosensitive silver paste provided in Examples 1 to 8, and the photosensitive silver paste provided in Comparative Examples 1 to 5.

[0127] Test method: Printing substrate: alumina ceramic sheet or ITO glass substrate; specifications: 50 mm × 50 mm × 1 mm.

[0128] Screen printing stencil: mesh number is 400; wire diameter is 18 µm; printing pattern is a 45 mm × 45 mm square pattern; printing thickness is 9~11 µm.

[0129] Pre-bake (60°C): 6 min.

[0130] Mask: 10~40 µm opening film mask.

[0131] Exposure machine exposure: exposure energy 100 mJ / cm 2 ; Exposure power 10 mW / cm 2 .

[0132] Development and cleaning: 0.4% Na2CO3 aqueous solution; development time 30 s; cleaning time 5 s; spray development pressure 0.1 MPa.

[0133] Post-baking (60℃): 10 min.

[0134] Sintering conditions: 280℃ debinding for 30 min, heating rate of 10℃ / min, 850℃ holding for 30 min, cooling rate of 10℃ / min.

[0135] (1) External expansion distance test: Use a 200x optical microscope to detect the actual silver line imaging line width of the mask at 20 µm. The external expansion distance = the silver line width at that location - 20.

[0136] (2) Curing depth test: Cut the cross section perpendicular to the silver wire direction, and use a 400x optical microscope to measure the height of the silver wire and the distance from the top of the silver wire to the beginning of severe alkaline lateral corrosion. Curing depth = silver wire height - distance from the top of the silver wire to the beginning of severe alkaline lateral corrosion.

[0137] (3) Resolution test: Use a 200x optical microscope to detect the actual line width and line spacing of the silver line on the mask at a line width and line spacing of 20um.

[0138] (4) Shrinkage test: Measure the height of the silver wire before and after sintering after sectioning. Shrinkage % = 1-the ratio of the thickness after sintering to the thickness before sintering.

[0139] (5) Resistivity test: The resistance value R at both ends of the test line is measured by a DC resistance tester.

[0140] The specific test results are shown in Table 1 below: Table 1

[0141] As can be seen from Table 1, compared with Comparative Examples 1-2, the glass powder for the photosensitive silver paste obtained by the embodiment 2 can effectively reduce the resistance and improve the resolution after ball milling and grading. Compared with Comparative Examples 3-5, the photosensitive silver paste obtained by the embodiment 1-6 can effectively reduce the resistivity, reduce the shrinkage rate, improve the solidification depth, and improve the reliability and product yield of the photosensitive silver paste and ceramic paste stack co-firing. By comparing Comparative Examples 3 and 5, the photosensitive silver paste obtained by regulating the active diluent can help improve the resolution. By comparing Examples 1, 5-8, and combining the above-mentioned effects of the glass powder for the photosensitive silver paste, the photosensitive silver paste obtained by regulating the photoinitiator can further reduce the overexpansion distance, improve the solidification depth, improve the resolution, and improve the resolution and stability of the high-silver-containing photosensitive silver paste. Figure 1 and Figure 2 The photosensitive silver paste obtained by regulating the photoinitiator can further reduce the overexpansion distance, improve the solidification depth, improve the resolution, and improve the resolution and stability of the high-silver-containing photosensitive silver paste.

[0142] In summary, the photosensitive silver paste prepared by using the alkali-soluble photosensitive resin, the active diluent, the photoinitiator, the organic solvent, the spherical silver powder, the glass powder for the photosensitive silver paste after ball milling and grading, and the additives has the advantages of high resolution, no undercut, low resistance, and low shrinkage rate. The photosensitive silver paste is used to prepare a multilayer chip inductor, which can reduce the resistance, improve the resolution, improve the yield, and improve the production efficiency.

[0143] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or make equivalent substitutions for part or all of the technical features; and these modifications or substitutions do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A low-resistance photosensitive silver paste, characterized in that: The raw materials for preparing the low-resistance photosensitive silver paste include, by weight: an alkali-soluble photosensitive resin, a reactive diluent, a photoinitiator, an organic solvent, spherical silver powder, and glass powder for the photosensitive silver paste; The particle size D50 of the photosensitive silver paste glass powder is 0.8-2 μm, and the maximum particle size of the photosensitive silver paste glass powder is 2-4 μm.

2. The low-resistance photosensitive silver paste according to claim 1, characterized in that: The raw materials for preparing the low-resistance photosensitive silver paste include, by weight, 10 to 30 parts of alkali-soluble photosensitive resin, 2 to 8 parts of reactive diluent, 0.2 to 3 parts of photoinitiator, 1 to 15 parts of organic solvent, 60 to 85 parts of spherical silver powder, and 0.5 to 3 parts of glass powder for photosensitive silver paste.

3. The low-resistance photosensitive silver paste according to claim 1 or 2, characterized in that: The glass powder for the photosensitive silver paste is glass powder that has been ball-milled and graded; Preferably, the ball milling medium is zirconia grinding medium balls; the diameter of the zirconia grinding medium balls is 1.0-3.0 mm; the ball-to-material ratio of the ball milling is (0.5-3):1; Preferably, the ball milling speed is 50-150 rpm, and the ball milling time is 10-24 h; Preferably, the glass powder includes low softening point glass powder and / or high softening point glass powder; Preferably, the softening point of the low-softening-point glass powder is 450-650°C; Preferably, the softening point of the high-softening-point glass powder is 700-900°C; Preferably, the expansion coefficient of the glass powder is 5×10 -6 / ℃~15×10 -6 / ℃; Preferably, the low softening point glass powder includes any one of SiO2-B2O3 glass powder, SiO2-B2O3-Li2O glass powder, SiO2-B2O3-Li2O-ZnO glass powder, SiO2-B2O3-K2O glass powder, SiO2-B2O3-K2O-ZnO glass powder or SiO2-B2O3-Bi2O3 glass powder, or a combination of at least two thereof; Preferably, the high softening point glass powder includes any one of SiO2-B2O3-CaO glass powder, SiO2B2O3-Al2O3 glass powder, SiO2-B2O3-TiO2 glass powder or SiO2-Al2O3-Na2O glass powder, or a combination of at least two of them.

4. The low-resistance photosensitive silver paste according to claim 1 or 2, characterized in that: The alkali-soluble photosensitive resin includes an epoxy acrylate resin with a high acid value; Preferably, the acid value of the epoxy acrylate resin is 25 to 150 mg KOH / g, preferably 50 to 100 mg KOH / g; Preferably, the molecular weight of the epoxy acrylate resin is 2000-50000 g / mol; Preferably, the functionality of the epoxy acrylate resin is 2 to 6; Preferably, the epoxy acrylate resin includes any one of novolac epoxy acrylate, modified novolac epoxy acrylate, o-methyl novolac epoxy acrylate or modified o-methyl novolac epoxy acrylate, or a combination of at least two thereof.

5. The low-resistance photosensitive silver paste according to claim 1 or 2, characterized in that: The reactive diluent includes any one of dipentaerythritol hexaacrylate, dipentaerythritol tetraacrylate, ethoxylated trimethylolpropane triacrylate, trimethylolpropane triacrylate, trimethylolpropane propoxy (3) triacrylate, trimethylolpropane ethoxy (3) triacrylate, 1,6-hexanediol diacrylate, dipropylene glycol diacrylate, tripropylene glycol diacrylate, 30 (ethoxy) bisphenol A diacrylate, 10 (ethoxy) bisphenol A diacrylate, 30 (ethoxy) bisphenol A dimethacrylate, 10 (ethoxy) bisphenol A dimethacrylate, methoxy polyethylene glycol 600 methacrylate, lauryl acrylate, isobornyl acrylate, isobornyl methacrylate or methacrylic acid, or a combination of at least two thereof; Preferably, the photoinitiator comprises any one of a cleavage-type free radical photoinitiator or a hydrogen abstraction-type free radical photoinitiator, or a combination of at least two thereof; Preferably, the photoinitiator includes any one of 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butanone, 2-methyl-1-(4-methylthiophenyl)-2-morpholino-1-propanone, diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide, phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, tetraethyl Michler's ketone, 1-[4-(phenylthio)phenyl]-1,2-octanedione 2-(O-benzoyloxime), 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-ethanone 1-(O-acetyloxime), 2-isopropylthioxanthone or 2,4-diethylthiazolone, or a combination of at least two thereof; Preferably, the raw materials for preparing the low-resistance photosensitive silver paste further include a co-initiator; Preferably, the mass ratio of the photoinitiator to the co-initiator is 1:(0-1.5); Preferably, the co-initiator includes any one or a combination of at least two of ethyl 4-dimethylaminobenzoate, 4,4'-bis(diethylamino)benzophenone, N-tolyldiethanolamine, isopentyl dimethylaminobenzoate, isopentyl diethylaminobenzoate, 5-mercapto-1-phenyl-1H-tetrazole, triethylamine or triethanolamine; Preferably, the organic solvent includes any one of diethylene glycol methyl ether, diethylene glycol butyl ether acetate, diethylene glycol ethyl ether, diethylene glycol monobutyl ether, diethylene glycol propyl ether, diethylene glycol dibutyl ether, ethylene glycol butyl ether acetate, mixed acid dimethyl ester, alcohol ester-12, terpineol, dipropylene glycol monomethyl ether, dipropylene glycol dimethyl ether or tetramethylbenzene, or a combination of at least two thereof.

6. The low-resistance photosensitive silver paste according to claim 1 or 2, characterized in that: The spherical silver powder includes spherical silver powder with a D50 of 0.2 to 5 μm; Preferably, the spherical silver powder comprises 50-100% of main silver powder and 0-50% of auxiliary silver powder by mass percentage; Preferably, the particle size D50 of the main silver powder is 1-2.5 μm, and the particle size D50 of the auxiliary silver powder is 0.4-1.0 μm; Preferably, the raw materials for preparing the low-resistance photosensitive silver paste further include: 0 to 3 parts of an auxiliary agent; Preferably, the auxiliary agent includes any one of a dispersant, a leveling agent, a defoaming agent or a thixotropic agent, or a combination of at least two thereof.

7. A method for preparing a low-resistance photosensitive silver paste according to any one of claims 1 to 6, characterized in that: The preparation method of the low-resistance photosensitive silver paste comprises: An alkali-soluble photosensitive resin, a reactive diluent, a photoinitiator and an organic solvent are mixed and stirred to obtain a glue solution; The spherical silver powder, the glass powder for the photosensitive silver paste and the glue are mixed, centrifuged and stirred, and ground to obtain the low-resistance photosensitive silver paste.

8. The method for preparing a low-resistance photosensitive silver paste according to claim 7, wherein: The stirring speed in the preparation of the glue solution is 100-400 rpm, and the stirring time is 2-5 h.

9. The method for preparing a low-resistance photosensitive silver paste according to claim 7, wherein: The centrifugal stirring speed in the preparation of the low-resistance photosensitive silver paste is 5000-10000 rpm, and the centrifugal stirring time is 30-90 s; Preferably, the grinding is performed using a three-roll mill; Preferably, the fineness of the low-resistance photosensitive silver paste obtained by grinding is less than 8 μm.

10. Use of the low-resistance photosensitive silver paste according to any one of claims 1 to 6 in preparing a multilayer chip inductor.

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