Thick-film resistor paste and preparation method thereof

Abstract

The invention belongs to the technical field of electronic paste, and particularly discloses thick-film resistor paste and a preparation method thereof. The resistance paste comprises the following components in percentage by mass: 45-75% of an inorganic component, 20-50% of an organic component and 0.1-10% of an organic ruthenium compound, wherein the inorganic component comprises ruthenium oxide, glass powder and an inorganic filler; the organic component comprises resin, a curing agent and a solvent. According to the invention, the organic ruthenium compound is added into the resistor paste, so that in the sintering process of the resistor paste, the organic ruthenium compound is gradually subjected to in-situ chemical reaction and is converted into ruthenium oxide to continuously fill pores generated by sintering decomposition of organic components, thereby effectively improving the sintering uniformity and density of the resistor layer; therefore, the resistance discreteness of the resistive layer can meet the use requirement.

Description

Technical Field

[0001] This invention belongs to the field of electronic paste technology, and specifically relates to a thick film resistor paste and its preparation method. Background Technology

[0002] Chip resistors are important electronic components widely used in thick-film circuits, hybrid integrated circuits, electronic devices, and other fields. The resistive characteristics of thick-film chip resistors mainly depend on their resistive layer, which is formed by printing thick-film resistive paste onto an insulating substrate and then sintering it.

[0003] As the application scenarios of surface mount resistors (SMRs) evolve towards miniaturization and high precision, higher demands are being placed on the precision of adjusting the characteristics of the resistive paste, particularly on the stringent requirements for resistance value dispersion. During the sintering process, existing resistive pastes generate micropores in the resistive layer due to the decomposition of organic components. This reduces the sintering uniformity and density of the resistive layer, thus affecting the resistance value dispersion after sintering. While the decrease in resistance dispersion caused by micropores is still within an acceptable range in low-to-medium precision applications, this problem severely impacts the performance of surface mount resistors in high-precision applications, significantly limiting the application scope of current resistive pastes. Therefore, there is an urgent need to improve the resistive paste formulation to meet the demands of small-size, high-precision applications. Summary of the Invention

[0004] In order to overcome at least one of the technical problems existing in the prior art, one of the objectives of the present invention is to provide a resistive paste.

[0005] The second objective of this invention is to provide a method for preparing a resistive paste.

[0006] The third objective of this invention is to provide a chip resistor.

[0007] The fourth objective of this invention is to provide an electronic product.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is as follows: The first aspect of the present invention provides a resistive paste comprising the following components by mass percentage: 45-75% inorganic components, 20-50% organic components, and 0.1-10% organic ruthenium compound, wherein the inorganic components include ruthenium oxide, glass powder, and inorganic fillers; and the organic components include resin, curing agent, and solvent.

[0009] This invention adds an organic ruthenium compound to the resistive slurry. During the sintering process of the resistive slurry, the organic ruthenium compound gradually undergoes an in-situ chemical reaction and is converted into ruthenium oxide, which is used to fill the pores caused by the sintering and decomposition of organic components. This effectively improves the sintering uniformity and sintering density of the resistive layer, thereby ensuring that the resistance value dispersion of the resistive layer meets the application requirements.

[0010] In some embodiments of the present invention, the mass percentage of the inorganic component is any value of 45%, 50%, 55%, 60%, 65%, 70%, 75%, or a range formed by any two of these values.

[0011] In some embodiments of the present invention, the mass percentage of the organic component is any value of 20%, 25%, 30%, 35%, 40%, 45%, 50%, or a range formed by any two of these values.

[0012] In some embodiments of the present invention, the organorruthenium compound is selected from at least one of dodecyltriruthenium, ruthenium dicene, ruthenium acetylacetonate, tri(triphenylphosphine)ruthenium carbonyl chloride, ruthenium oxalate, ruthenium carbonyl chloride, and ruthenium triphenylphosphine chloride.

[0013] In some embodiments of the present invention, the mass percentage of the organorruthenium compound is any one of 0.1%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, or a range formed by any two of these values.

[0014] In some embodiments of the present invention, the inorganic components, based on the total mass of the inorganic components as 100%, include the following components by mass percentage: ruthenium oxide 1-40%, glass powder 30-75%, and inorganic filler 1-30%.

[0015] In some embodiments of the present invention, the mass percentage of ruthenium oxide is any value of 1%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, or a range formed by any two of these values.

[0016] In some embodiments of the present invention, the average particle size of the ruthenium oxide is 50 nm to 1000 nm; in some embodiments of the present invention, the average particle size of the ruthenium oxide is any value of 50 nm, 100 nm, 200 nm, 400 nm, 500 nm, 600 nm, 800 nm, 1000 nm or a range formed by any two of these values.

[0017] In some embodiments of the present invention, the mass percentage of the glass powder is any value or a range formed by any two of 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, and 75%.

[0018] In some embodiments of the present invention, the average particle size of the glass powder is 0.5 μm to 5 μm; in some embodiments of the present invention, the average particle size of the glass powder is any value or a range formed by any two of 0.5 μm, 1 μm, 1.5 μm, 2 μm, 2.5 μm, 3 μm, 3.5 μm, 4 μm, 4.5 μm, and 5 μm.

[0019] In some embodiments of the present invention, the glass powder comprises the following components by mass percentage, based on the total mass of the glass powder as 100%: 30-60% SiO2, 20-45% B2O3, 1-10% ZnO, 1-10% CaO, and 1-10% ZrO2.

[0020] In some embodiments of the present invention, the mass percentage of SiO2 in the glass powder is any value of 30%, 35%, 40%, 45%, 50%, 55%, 60%, or a range formed by any two of these values.

[0021] In some embodiments of the present invention, the mass percentage of B2O3 in the glass powder is any one of 20%, 25%, 30%, 35%, 40%, 45%, or a range formed by any two of these values.

[0022] In some embodiments of the present invention, the mass percentage of ZnO in the glass powder is any value or a range formed by any two of the following: 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%.

[0023] In some embodiments of the present invention, the mass percentage of CaO in the glass powder is any one of 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, or a range formed by any two of these values.

[0024] In some embodiments of the present invention, the mass percentage of ZrO2 in the glass powder is any value or a range formed by any two of the following: 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%.

[0025] In some embodiments of the present invention, the inorganic filler is selected from at least one of alumina, copper oxide, zirconium oxide, calcium oxide, zinc oxide, and manganese oxide.

[0026] In some embodiments of the present invention, the average particle size of the inorganic filler is 100nm to 1000nm; in some embodiments of the present invention, the average particle size of the inorganic filler is any value of 100nm, 200nm, 400nm, 500nm, 600nm, 800nm, 1000nm or a range formed by any two of them.

[0027] In some embodiments of the present invention, the mass percentage of the inorganic filler is any one of 1%, 5%, 10%, 15%, 20%, 25%, 30%, or a range formed by any two of these values.

[0028] In some embodiments of the present invention, the organic components, based on a total mass of 100%, include the following components by mass percentage: 5-50% resin, 5-20% curing agent, and 30-75% solvent.

[0029] In some embodiments of the present invention, the resin is selected from at least one of methylcellulose, ethylcellulose, acrylic resin, epoxy resin, alkyd resin, terpene resin, and modified rosin.

[0030] In some embodiments of the present invention, the mass percentage of the resin is any value or a range formed by any two of 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, and 50%.

[0031] In some embodiments of the present invention, the curing agent is selected from at least one of bisphenol A resin, isocyanate, unsaturated acrylic resin, polyvinyl maleic anhydride resin, and polyvinyl butyral.

[0032] In some embodiments of the present invention, the mass percentage of the curing agent is any value of 5%, 10%, 15%, 20%, or a range formed by any two of these values.

[0033] In some embodiments of the present invention, the solvent is selected from at least one of terpineol, butyl carbitol, isopropanol, butyl carbitol acetate, diethylene glycol monobutyl ether, turpentine, isobornyl acetate, dibutyl phthalate, and decyl alcohol ester.

[0034] In some embodiments of the present invention, the mass percentage of the solvent is any value of 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, or a range formed by any two of these values.

[0035] In some embodiments of the present invention, the mass ratio of the organorruthenium compound to the ruthenium oxide is (0.04~1):1; in some embodiments of the present invention, the mass ratio of the organorruthenium compound to the ruthenium oxide is any value or a range formed by any two of the following: 0.04:1, 0.05:1, 0.1:1, 0.15:1, 0.2:1, 0.25:1, 0.3:1, 0.4:1, 0.5:1, 0.6:1, 0.7:1, 0.8:1, 0.9:1, 1:1; in some preferred embodiments of the present invention, the mass ratio of the organorruthenium compound to the ruthenium oxide is (0.05~0.3):1. When the mass ratio of organic ruthenium compound to ruthenium oxide is (0.05~0.3):1, on the one hand, the inorganic components are uniformly dispersed during the preparation of the resistance slurry, making them less prone to agglomeration, thus improving the dispersion uniformity of the slurry and resulting in better sintering uniformity of the sintered resistance layer; on the other hand, the organic ruthenium compound can be transformed into sufficient ruthenium oxide during the sintering process to fill the pores generated by the decomposition of organic components, thereby increasing the density of the sintered resistance layer and optimizing the resistance value dispersion of the resistance layer, making the RSD value ≤2.5%.

[0036] In some embodiments of the present invention, the mass ratio of the organorruthenium compound to the curing agent is (0.04~5.2):1; in some embodiments of the present invention, the mass ratio of the organorruthenium compound to the curing agent is any value or a range formed by any two of 0.04:1, 0.1:1, 0.3:1, 0.5:1, 1:1, 1.5:1, 2:1, 2.5:1, 3:1, 3.5:1, 4:1, 4.5:1, 5:1, and 5.2:1; in some preferred embodiments of the present invention, the mass ratio of the organorruthenium compound to the curing agent is (0.3~5):1. After the resistive paste is printed onto the substrate and dried, a dry film is obtained. The sources of adhesion for the dry film include covalent and ionic bonds in the curing agent and hydrogen bonds in the organorruthenium compound. When the amount of organorruthenium compound increases, the hydrogen bond content increases. Since the strength of hydrogen bonds is much lower than that of covalent and ionic bonds, the adhesion will decrease. When the amount of organorruthenium compound decreases, the amount of ruthenium oxide generated by the organorruthenium compound decreases, the filling effect on pores decreases, and the resistance dispersion performance deteriorates. Therefore, when the mass ratio of organorruthenium compound to curing agent is (0.3~5):1, the performance of both bonding strength and resistance dispersion can be balanced, so that the resistive layer made from the resistive paste has both excellent bonding strength and good resistance dispersion, and the RSD is ≤2.5%.

[0037] In some embodiments of the present invention, the organic components, based on a total mass of 100%, further comprise 0.5% to 10% by mass of organic additives; in some embodiments of the present invention, the organic additives are any value or a range formed by any combination of 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, and 10%.

[0038] In some embodiments of the present invention, the organic additive is selected from at least one of sodium dodecyl sulfate, methyl pentanol, aminopropyl dioleate, oleyl amino oleate, and lecithin.

[0039] The second aspect of the present invention provides a method for preparing the resistive paste described in the first aspect of the present invention, comprising the following steps: Resin, organorruthenium compound, curing agent, optional organic additives, and solvent are mixed to obtain an organic slurry; ruthenium oxide, glass powder, and inorganic filler are mixed to obtain an inorganic powder. The organic slurry and the inorganic powder are mixed and then rolled to obtain the resistive slurry.

[0040] In some embodiments of the present invention, the mixing temperature during the preparation of the organic slurry is 60~120°C.

[0041] In some embodiments of the present invention, the mixing speed during the preparation of the organic slurry is 10~480 rpm.

[0042] In some embodiments of the invention, the organic slurry is obtained by heating and mixing a resin and a solvent, and then mixing it with an organorruthenium compound and optionally added organic additives.

[0043] In some embodiments of the present invention, the temperature of the heating and mixing is 60~120°C.

[0044] In some embodiments of the present invention, the rotation speed of the heating and mixing is 10~480 rpm.

[0045] In some embodiments of the present invention, the mixing speed in the post-mixing rolling step is 60~720 rpm.

[0046] In some embodiments of the present invention, the mixing in the post-mixing rolling step is performed by stirring with a straight blade paddle.

[0047] A third aspect of the present invention provides a chip resistor comprising a resistive layer; said resistive layer is prepared using the resistive paste described in the first aspect of the present invention.

[0048] A fourth aspect of the present invention provides an electronic product comprising a component made of the resistive paste described in the first aspect of the present invention or a chip resistor described in the third aspect of the present invention.

[0049] The beneficial effects of this invention are: by adding an organic ruthenium compound to the resistive slurry, the organic ruthenium compound gradually undergoes an in-situ chemical reaction during the sintering process of the resistive slurry and is converted into ruthenium oxide to continuously fill the pores caused by the sintering and decomposition of organic components, thereby effectively improving the sintering uniformity and density of the resistive layer. Therefore, it can ensure that the resistance value dispersion of the resistive layer meets the requirements for use.

[0050] The resistive paste of this invention can achieve a resistance value dispersion RSD ≤ 2.5% and strong dry film adhesion without peeling by adjusting the content ratio of organic ruthenium compound, ruthenium oxide and curing agent. Detailed Implementation

[0051] The following examples provide a more detailed description of the specific implementation of the present invention, but the implementation and protection of the present invention are not limited thereto. It should be noted that any processes not specifically described below are methods that can be implemented or understood by those skilled in the art by referring to existing technology. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0052] The raw material information used in the following examples and comparative examples is as follows: Average particle size of ruthenium oxide: 500 nm; Average particle size of inorganic filler: 500 nm; Average particle size of glass powder: 1 μm; The glass powder numbers and their corresponding specific formulas are shown in Table 1 below.

[0053] Table 1. Formulation of glass powder

[0054] Example 1 This example provides a thick-film resistor paste, composed of the following components by mass percentage: 75% inorganic components, 24.9% organic components, and 0.1% organic ruthenium compound. The inorganic components, with a total mass of 100%, consist of the following components by mass percentage: ruthenium oxide 1%, glass powder (G1) 75%, and inorganic filler (alumina) 24%. Based on the total mass of the organic components being 100%, the organic components consist of the following components by mass percentage: resin (i.e., ethyl cellulose) 50%, solvent (i.e., terpineol) 30%, curing agent (i.e., bisphenol A resin) 10%, and organic additive (i.e., sodium dodecyl sulfate) 10%. The organorruthenium compound is dodecacarbonyltriruthenium, and the mass ratio of the organorruthenium compound to ruthenium oxide (denoted as ratio a) is 0.1333; the mass ratio of the organorruthenium compound to the curing agent (denoted as ratio b) is 0.0402. The specific formulas are shown in Tables 2-4 below.

[0055] Examples 2-21 The specific formulations of the thick film resistor pastes in Examples 2-21 are shown in Tables 2-4 below.

[0056] Comparative Examples 1-4 The specific formulations of the thick film resistor pastes in Comparative Examples 1 to 4 are shown in Tables 2 to 4 below.

[0057] Table 2 Formulation and ratios of thick film resistor paste (ab)

[0058] Table 3 Formulation of Inorganic Components

[0059] Table 4 Formulation of Organic Components

[0060] In Tables 1-4 of this invention, the types and contents of components such as ruthenium oxide, glass powder, inorganic fillers, curing agents, and organorruthenium compounds can all be detected using conventional detection methods in the prior art, including but not limited to the detection methods listed in this invention. For example, the types and contents of ruthenium oxide, glass powder, and inorganic fillers can be detected by XRD, ICP, X-ray photoelectron spectroscopy (XRF), etc.; the types and contents of curing agents can be obtained by liquid chromatography-mass spectrometry or infrared spectroscopy. The types and contents of organorruthenium compounds can be detected by XRF, XRD, or infrared spectroscopy.

[0061] The thick-film resistor pastes in Examples 1-21 and Comparative Examples 1-4 can all be prepared according to or by referring to the following preparation method, the specific steps of which are as follows: a. Heat and stir at 80℃ (using a straight blade paddle, at 280 rpm) to uniformly dissolve the resin in the solvent. Then add the organic ruthenium compound, curing agent, and organic additives and mix. Filter and cool to obtain a viscous colloidal organic carrier. Premix and disperse ruthenium oxide, glass powder, and inorganic filler to obtain an inorganic mixed powder. b. Add the inorganic mixed powder to the organic carrier according to the formula ratio, stir first (stirring method is straight blade paddle, speed is 580 rpm) for premixing, and then fully disperse evenly through a three-roll mill to obtain the resistance slurry.

[0062] Performance testing: Using the resistive layer dimensions (effective size 0.6mm × 0.3mm, sintered film thickness 6μm-8μm, average thickness 7μm) of a 0201 chip resistor as test samples, the thick-film resistive pastes from Examples 1-21 and Comparative Examples 1-4 were screen-printed onto an alumina substrate. The pastes were dried at 150°C for 15 minutes to form a dry film, and then sintered in air at 850°C to obtain the resistive layer test samples. The number of test samples was n. The resistance value R, resistance dispersion, and dry film adhesion of the resistive layer test samples were then tested according to the following test methods: (1) Resistance R test: The resistance value Ri of each sample was measured using a resistance meter, and the average resistance value of all tested samples was calculated. n is set to 500.

[0063] (2) Resistance value discreteness: Test method: The resistance value Ri of each sample is measured using a resistance meter, and the resistance variation factor is calculated using a formula.

[0064] n is set to 500.

[0065] Performance requirements: RSD ≤ 5%. Among them, RSD% ≤ 2.5% indicates excellent performance; 2.5% < RSD% ≤ 5% indicates acceptable performance.

[0066] (3) Dry film adhesion performance test: Test method: Apply 3M SCOTCH 600 tape to the dry film, let it stand for 2 minutes, then peel it off at a uniform speed and check the dry film peeling; Performance requirement: No dry film peeling is acceptable.

[0067] The performance test results of the resistive layer test samples obtained according to the above test method are shown in Table 5 below.

[0068] Table 5 Performance test results of the resistive layer

[0069] As shown in Table 5, by introducing organic ruthenium compounds into the thick film resistor paste, the present invention can significantly improve the resistance dispersion of the prepared resistor layer, making the resistance dispersion of the resistor layer ≤5%. At the same time, by adjusting the ratios a and b, the resistance dispersion of the resistor layer can be further reduced, and the resistor layer has a strong bonding strength, making it less likely to fall off during use.

[0070] The embodiments of the present invention have been described in detail above. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention. Furthermore, the embodiments of the present invention and the features thereof can be combined with each other unless otherwise specified.

Claims

1. A resistive paste, characterized in that: It comprises the following components by mass percentage: 45-75% inorganic components, 20-50% organic components, and 0.1-10% organic ruthenium compounds, wherein the inorganic components include ruthenium oxide, glass powder, and inorganic fillers; and the organic components include resin, curing agent, and solvent.

2. The resistive paste according to claim 1, characterized in that: The organorruthenium compound is selected from at least one of dodecyltriruthenium, ruthenium dicene, ruthenium acetylacetonate, tris(triphenylphosphine)carbonyl chloride, ruthenium oxalate, ruthenium carbonyl chloride, and ruthenium triphenylphosphine chloride. And / or, the inorganic filler is selected from at least one of alumina, copper oxide, zirconium oxide, calcium oxide, zinc oxide, and manganese oxide; And / or, the resin is selected from at least one of methylcellulose, ethylcellulose, acrylic resin, epoxy resin, alkyd resin, terpene resin, and modified rosin; And / or, the curing agent is selected from at least one of bisphenol A resin, isocyanate, unsaturated acrylic resin, polyvinyl maleic anhydride resin, and polyvinyl butyral.

3. The resistive paste according to claim 1, characterized in that: Based on the total mass of the inorganic components as 100%, the inorganic components include the following components by mass percentage: ruthenium oxide 1~40%, glass powder 30~75%, and inorganic filler 1~30%.

4. The resistive paste according to claim 1, characterized in that: Based on the total mass of the organic components as 100%, the organic components include the following components by mass percentage: resin 5~50%, curing agent 5~20%, and solvent 30~75%.

5. The resistive paste according to claim 1, characterized in that: The mass ratio of the organorruthenium compound to the ruthenium oxide is (0.04~1):1; And / or, the mass ratio of the organorruthenium compound to the curing agent is (0.04~5.2):

1.

6. The resistive paste according to claim 1, characterized in that: Based on the total mass of the glass powder as 100%, the glass powder comprises the following components by mass percentage: 30-60% SiO2, 20-45% B2O3, 1-10% ZnO, 1-10% CaO, and 1-10% ZrO2.

7. The resistive paste according to claim 1, characterized in that: Based on the total mass of the organic components as 100%, the organic components further contain 0.5% to 10% organic additives by mass; preferably, the organic additives are selected from at least one of sodium dodecyl sulfate, methyl pentanol, aminopropyl dioleate, oleyl amino oleate, and lecithin.

8. The method for preparing the resistive paste according to any one of claims 1 to 7, characterized in that: Includes the following steps: Resin, organorruthenium compound, curing agent, optional organic additives, and solvent are mixed to obtain an organic slurry; ruthenium oxide, glass powder, and inorganic filler are mixed to obtain an inorganic powder. The organic slurry and the inorganic powder are mixed and then rolled to obtain the resistive slurry.

9. A chip resistor, characterized in that: It includes a resistive layer; the resistive layer is prepared using the resistive paste according to any one of claims 1 to 7.

10. An electronic product, characterized in that: Includes components made from the resistive paste according to any one of claims 1 to 7 or the chip resistor according to claim 9.

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