阅读说明：本技术 一种低尺寸效应的厚膜电阻浆料 (Thick film resistor paste with low size effect ) 是由 鹿宁 赵科良 吴高鹏 殷美 党丽萍 王妮 孙社稷 何依青 于 2021-09-01 设计创作，主要内容包括：本发明公开了一种低尺寸效应的厚膜电阻浆料,所述厚膜电阻浆料包含功能材料、玻璃粉、轻烧莫来石、白云石、有机载体和任选的添加剂。本发明通过引入轻烧莫来石和白云石对电阻烧结后的图形效应进行优化,使电阻具备了图形效应不明显的优点,可满足不同图形尺寸的厚膜集成电路和不同规格的片式电阻器产品的使用要求。(The invention discloses a thick film resistor paste with low size effect, which comprises a functional material, glass powder, light-burned mullite, dolomite, an organic carrier and optional additives. The invention optimizes the graphic effect of the sintered resistor by introducing the light burned mullite and the dolomite, so that the resistor has the advantage of unobvious graphic effect and can meet the use requirements of thick film integrated circuits with different graphic sizes and chip resistor products with different specifications.)

1. A thick film resistor paste comprising a functional material, glass frit, calcined mullite, dolomite, an organic vehicle, and optionally an additive; based on the total mass of the thick film resistor paste, the thick film resistor paste contains 15wt% -45wt% of functional materials, 10wt% -40wt% of glass powder, 5wt% -15wt% of light-burned mullite and dolomite, 30wt% -45wt% of organic carriers and 0-5wt% of additives.

2. The thick-film resistor paste of claim 1 wherein the functional material comprises one or more selected from the group consisting of silver powder, palladium powder, ruthenium dioxide, and lead ruthenate.

3. The thick-film resistor paste of claim 1 wherein the glass frit comprises a Pb-B-Ca-Si bulk glass frit and a Pb-B-Si bulk glass frit.

4. The thick-film resistor paste of claim 1 wherein said additive comprises a material selected from the group consisting of elemental copper, copper-containing compounds, elemental manganese, manganese-containing compounds, elemental tantalum, tantalum-containing compounds, Nb₂O₅And Sb₂O₃One or more of (a).

5. The thick-film resistor paste of claim 4,

the additive comprises CuO and MnO₂(ii) a And/or

The content of the additive in the thick film resistor paste is 1wt% -5wt% based on the total mass of the thick film resistor paste.

6. The thick-film resistor paste of claim 1 wherein the thick-film resistor paste has one or more of the following characteristics:

the granularity of the glass powder is 1-2 μm;

the granularity of the light-burned mullite and the dolomite is 0.8-1.3 mu m;

the organic carrier comprises resin, an organic additive and an organic solvent, and based on the total mass of the organic carrier, the content of the resin in the organic carrier is 8wt% -15wt%, the content of the organic additive is 1wt% -5wt%, and the content of the organic solvent is 80wt% -90 wt%;

the particle size of the additive is 1-2 μm.

7. The thick-film resistor paste of claim 6 wherein the thick-film resistor paste has one or more of the following characteristics:

the resin comprises one or more selected from rosin resin, ethyl cellulose, hydroxy cellulose and methyl cellulose;

the organic additive comprises lecithin;

the organic solvent includes one or more selected from ester solvents, alcohol solvents and ether solvents.

8. A chip resistor prepared using the thick film resistor paste according to any one of claims 1 to 7.

9. A circuit board comprising a substrate and a thick-film resistor formed on the substrate, the thick-film resistor being prepared using the thick-film resistor paste according to any one of claims 1 to 7.

10. Use of light burned mullite and dolomite to reduce the dimensional effect of a chip resistor or thick film resistor.

Technical Field

The invention belongs to the field of electronic paste, and particularly relates to thick film resistor paste with a low size effect.

Background

The thick film resistor paste is a technology-intensive product integrating multiple subject fields of metallurgy, chemistry, materials, electronic technology, analysis and test technology and the like. To meet the requirements of printing and sintering processes and practical application, the resistance paste must have printability, functional properties and process compatibility. The common resistance paste is a paste formed by mixing a functional phase, a binding phase, an additive and an organic carrier according to a certain proportion.

The thick film resistor paste is used as a raw material for producing thick film integrated circuits and chip resistors, and the paste is required to have a wider resistance range of 0.1-10M omega, so that the requirements of the integrated circuits and chip resistor products on resistance under various printed patterns and product sizes can be met.

The resistance of the resistor is proportional to the resistivity of the resistive material and the length of the resistor, and inversely proportional to the cross-sectional area of the resistor. It is generally considered that the resistivity of the resistor material does not change with the dimensional change of the resistor, and when the thickness of the resistor is constant and the ratio of the length to the width is constant, the resistance value of the resistor should be constant. However, in the case of a thick film resistor, there is a phenomenon that the resistance value of the resistor changes with dimensional change, which is called a dimensional effect (also called a pattern effect) of the thick film resistor.

The existing thick film resistor paste has higher size effect, and when the paste is applied to an integrated circuit, the problem that the resistance value of a resistor printed with different patterns has larger deviation can occur, so that troubles are caused in the design process of the integrated circuit; when the method is applied to the chip resistor, the resistance values of the resistors with different specifications are different greatly, and a chip resistor manufacturer needs to select and adjust the resistance paste aiming at the resistors with different specifications, so that the production management is inconvenient.

Therefore, there is a need for a thick film resistor paste that can meet the performance requirements of thick film integrated circuits and chip resistors and that has low dimensional effect characteristics.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides the thick film resistor paste which is suitable for the product performance requirements of thick film integrated circuits and chip resistors and has the characteristic of low size effect. The low-size effect thick film resistor paste has the advantages of wide resistance range and easy control of temperature coefficient, meets the product performance requirements of thick film integrated circuits and chip resistors, has the characteristic of low-size effect, and can be simultaneously applied to thick film integrated circuits with different printed patterns and chip resistor products with different size specifications.

Specifically, the invention provides a thick film resistor paste which comprises a functional material, glass powder, light-burned mullite, dolomite, an organic carrier and optional additives; based on the total mass of the thick film resistor paste, the thick film resistor paste contains 15wt% -45wt% of functional materials, 10wt% -40wt% of glass powder, 5wt% -15wt% of light-burned mullite and dolomite, 30wt% -45wt% of organic carriers and 0-5wt% of additives.

In one or more embodiments, the mass ratio of light-burned mullite to dolomite in the thick film resistor paste is 2: 1 to 1: 2, preferably 2: 1 to 1: 1.

in one or more embodiments, the functional material includes one or more selected from the group consisting of silver powder, palladium powder, ruthenium dioxide, and lead ruthenate.

In one or more embodiments, the glass frit includes a Pb-B-Ca-Si bulk glass frit and a Pb-B-Si bulk glass frit, and the mass ratio of the Pb-B-Ca-Si bulk glass frit and the Pb-B-Si bulk glass frit is preferably 1: 4 to 4: 1, e.g. 1: 4 to 2: 1. 8: 27 to 11: 6.

in one or more embodiments, the addition isThe agent comprises copper, copper-containing compound, manganese-containing compound, tantalum-containing compound, and Nb₂O₅And Sb₂O₃One or more of (a).

In one or more embodiments, the additive includes CuO and MnO₂。

In one or more embodiments, the additive is present in the thick film resistor paste in an amount of 1wt% to 5wt%, based on the total mass of the thick film resistor paste.

In one or more embodiments, the glass frit has a particle size of 1 μm to 2 μm.

In one or more embodiments, the light calcined mullite and the dolomite have a particle size of 0.8 μm to 1.3 μm.

In one or more embodiments, the organic vehicle comprises a resin, an organic additive, and an organic solvent, and the organic vehicle comprises from 8wt% to 15wt% of the resin, from 1wt% to 5wt% of the organic additive, and from 80wt% to 90wt% of the organic solvent, based on the total mass of the organic vehicle.

In one or more embodiments, the particle size of the additive is from 1 μm to 2 μm.

In one or more embodiments, the resin comprises one or more selected from rosin resin, ethyl cellulose, hydroxy cellulose, and methyl cellulose.

In one or more embodiments, the organic additive includes lecithin.

In one or more embodiments, the organic solvent includes one or more selected from the group consisting of an ester solvent, an alcohol solvent, and an ether solvent.

The invention also provides a chip resistor prepared by using the thick film resistor paste according to any embodiment of the invention.

The invention also provides a circuit board comprising a substrate and a thick film resistor formed on the substrate, wherein the thick film resistor is prepared by using the thick film resistor paste according to any embodiment of the invention.

The invention also provides the use of light burned mullite and dolomite to reduce the dimensional effect of a chip resistor or thick film resistor.

Detailed Description

To make the features and effects of the present invention comprehensible to those skilled in the art, general description and definitions are made below with reference to terms and expressions mentioned in the specification and claims. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

The theory or mechanism described and disclosed herein, whether correct or incorrect, should not limit the scope of the present invention in any way, i.e., the present disclosure may be practiced without limitation to any particular theory or mechanism.

In this context, for the sake of brevity, not all possible combinations of features in the various embodiments or examples are described. Therefore, the respective features in the respective embodiments or examples may be arbitrarily combined as long as there is no contradiction between the combinations of the features, and all the possible combinations should be considered as the scope of the present specification.

All features defined herein as numerical ranges or percentage ranges, such as values, amounts, levels and concentrations, are for brevity and convenience only. Accordingly, the description of numerical ranges or percentage ranges should be considered to cover and specifically disclose all possible subranges and individual numerical values (including integers and fractions) within the range.

Herein, the sum of the percentages of all the components of the composition is equal to 100%.

Unless otherwise specified herein, "comprise," include, "" contain, "and the like, encompass the meanings of" consisting essentially of … … "and" consisting of … …, "i.e.," a comprises a "encompasses the meanings of" a comprises a and others, "" a consists essentially of "and" a consists of a. Herein, unless otherwise specified, "consisting essentially of … …" is understood to mean "consisting of … …% or more, preferably 90% or more, more preferably 95% or more".

The thick film resistor paste is a paste formed by rolling and mixing solid powder and an organic medium, and is a basic material for manufacturing a thick film resistor and a chip resistor. The components of the thick film resistor paste generally include a functional phase, a glass binder phase, an organic vehicle, and optional additives. The inventor of the invention finds that the addition of a combination of a proper amount of light-burned mullite and dolomite to the thick film resistor paste can reduce the size effect of the thick film resistor, namely, reduce the change of the resistivity of the thick film resistor caused by the size change.

Functional phase

The functional phase of the thick film resistor paste includes one or more functional materials. The functional material in the thick film resistor paste is mainly used for regulating the resistance value of the thick film resistor and can comprise various conductive powders commonly used in the thick film resistor paste. Examples of the conductive powder include, but are not limited to, silver powder, platinum group metal (including ruthenium, rhodium, palladium, osmium, iridium, platinum, and alloys thereof) powder, and platinum group metal-containing compounds (e.g., oxides, salts, and the like).

The functional phase is present in the thick-film resistor paste of the present invention in an amount of 15wt% to 45wt%, for example 18wt%, 20wt%, 24wt%, 28wt%, 30wt%, 32wt%, 36wt%, based on the total mass of the thick-film resistor paste.

The control of the resistance value of the thick film resistor can be realized by using functional materials with different conductivity. For example, a change in the order of magnitude of the resistance value of the thick film resistor can be achieved by using one or more of a functional material excellent in conductivity (e.g., silver powder, palladium powder), a functional material moderate in conductivity (e.g., ruthenium dioxide), and a functional material poor in conductivity (e.g., lead ruthenate). Thus, in some embodiments, the functional material in the thick-film resistor paste of the present invention includes one or more selected from the group consisting of silver powder, palladium powder, ruthenium dioxide, and lead ruthenate. For example, the functional material in the thick-film resistor paste of the present invention may include (1) silver powder and/or palladium powder and (2) ruthenium dioxide, or include ruthenium dioxide and lead ruthenate, or include lead ruthenate. When a plurality of functional materials are used, the ratio between the functional materials can be determined according to the requirement of the resistance value. For example, when the functional material includes silver powder, palladium powder, and ruthenium dioxide, the mass ratio between the silver powder, palladium powder, and ruthenium dioxide may be (2-4): (1-3): 1, e.g., 3: 2: 1; when the functional material comprises ruthenium dioxide and lead ruthenate, the mass ratio of the ruthenium dioxide to the lead ruthenate can be (1-2): 1, e.g. 1.4: 1. in embodiments where the functional material in the thick film resistor paste includes one or more selected from the group consisting of silver powder, palladium powder, ruthenium dioxide, and lead ruthenate, the total mass of the silver powder, palladium powder, ruthenium dioxide, and lead ruthenate may comprise more than 80%, such as more than 90%, more than 95%, 100% of the total mass of the functional material in the thick film resistor paste.

In the present invention, the particle size of the functional material may be 1 μm to 3 μm. Herein, the particle size refers to the average particle size of the powder. The particle size of the silver powder is preferably 1 μm to 3 μm, for example 2 μm. The average specific surface area of the palladium powder is preferably 5m²/g-15m²In g, e.g. 10m²(ii) in terms of/g. The average specific surface area of the ruthenium dioxide is preferably 25m²/g-55m²G, e.g. 40m²(ii) in terms of/g. The average specific surface area of the lead ruthenate is preferably 3m²/g-10m²G, e.g. 6m²/g。

Glass binder phase

The glass binder phase of the thick film resistor paste includes one or more glass frits. The glass powder is generally prepared from glass powder raw materials through processes of melting, quenching, crushing, ball milling and the like, for example, the raw materials of the glass powder can be uniformly mixed, and the obtained mixture is placed in a melting furnace for melting to obtain a glass solution; quenching, for example water quenching, the glass solution to obtain glass; the glass is crushed into glass slag, and then the glass slag is ball-milled into glass powder. The raw material of the glass frit in the thick film resistor paste may include one or more selected from the following materials: pb₃O₄、PbO、B₂O₃、CaO、SiO₂、BaO、Al₂O₃、Na₂O、K₂O and ZnO. The smelting temperature can be 1200-1400 ℃, for example 1350 +/-50 ℃, and the holding time can be 1-2 h, for example 1.5 h.

The amount of glass binder phase in the thick film resistor paste of the present invention is 10wt% to 40wt%, for example 17wt%, 20wt%, 24wt%, 25wt%, 27wt%, 29wt%, 30wt%, 32wt%, 33wt%, 34wt%, 35wt%, 38wt%, based on the total mass of the thick film resistor paste.

Two or more than two kinds of glass powder can be used as the glass bonding phase of the thick film resistor paste, wherein one kind of glass powder with higher melting point is used as the skeleton structure of the thick film resistor paste, and the other glass powder with lower melting point plays the role of bonding and dispersing the functional phase. For example, in some embodiments, the glass binder phase of the thick-film resistor paste of the present invention includes Pb-B-Ca-Si bulk glass frit and Pb-B-Si bulk glass frit, which may be present in a mass ratio of 1: 5 to 5: 1, e.g. 1: 4 to 4: 1. 1: 4 to 2: 1. 8: 27 to 11: 6. in these embodiments, the total mass of the Pb-B-Ca-Si bulk glass frit and the Pb-B-Si bulk glass frit may account for more than 80%, such as more than 90%, more than 95%, 100% of the total mass of the glass binder phase in the thick film resistor paste.

In the present invention, the Pb-B-Ca-Si system glass powder is a glass powder containing positive elements mainly Pb, B, Ca and Si. The total mass of Pb, B, Ca and Si is usually 80% or more, for example 90% or more, 95% or more and 100% or more of the total mass of positive valence elements in the Pb-B-Ca-Si system glass powder. The main raw material of the Pb-B-Ca-Si system glass powder can be Pb₃O₄、CaO、SiO₂And B₂O₃。Pb₃O₄、CaO、SiO₂And B₂O₃The total mass of (B) may be 80% or more, for example 90% or more, 95% or more, or 100% of the total mass of the raw materials of the Pb-B-Ca-Si bulk glass powder. In some embodiments, the Pb-B-Ca-Si bulk glass frit raw material comprises, based on the total mass of the Pb-B-Ca-Si bulk glass frit raw material: from 40% to 50%, for example 45%, by weight of Pb₃O₄25% to 35%, for example 28%, CaO, 20% to 25%, for example 23%, SiO₂And 1% to 10%, for example 4%, by weight of B₂O₃。

In the present invention, the Pb-B-Si system glass powder is a glass powder containing positive elements mainly Pb, B and Si. The total mass of Pb, B and Si is usually based on the total mass of positive valence elements in the Pb-B-Si system glass powder80% or more, for example 90% or more, 95% or more, 100%. The main raw material of the Pb-B-Si system glass powder can be Pb₃O₄、SiO₂And B₂O₃。Pb₃O₄、SiO₂And B₂O₃The total mass of (A) may be 80% or more, for example 90% or more, 95% or more, or 100% of the total mass of the raw materials of the Pb-B-Si bulk glass powder. In some embodiments, the Pb-B-Si bulk glass frit raw material comprises, based on the total mass of the Pb-B-Si bulk glass frit raw material: 50% to 70%, for example 65%, by weight of Pb₃O₄10% to 30% by weight, for example 20% by weight, of SiO₂And 10% to 20% by weight, for example 15% by weight, of B₂O₃。

In the present invention, the particle size of the glass frit (e.g., Pb-B-Ca-Si bulk glass frit, Pb-B-Si bulk glass frit) is preferably 1 μm to 2 μm, for example, 1.5. mu.m.

Organic vehicle

The organic vehicle in the thick film resistor paste typically includes a resin, an organic solvent, and optionally an organic additive. The organic vehicle is present in the thick-film resistor paste of the invention in an amount of 30wt% to 45wt%, for example 34wt%, 35wt%, 40wt%, 41wt%, based on the total mass of the resistor paste.

The resin is used to make the electronic paste have a certain viscosity. The resin suitable for the present invention may be one or more selected from rosin resin, ethyl cellulose, hydroxy cellulose and methyl cellulose. In some embodiments, the resin used in the present invention is ethyl cellulose. The amount of resin used is generally from 8wt% to 20wt%, for example 8wt%, 10wt%, 15wt% of the total weight of the organic vehicle.

The organic solvent is generally a relatively viscous liquid organic substance, and the molecule of the organic solvent generally contains polar groups, so that the organic solvent can dissolve resin, generally has a high boiling point, and is not easy to volatilize at normal temperature. The organic solvent suitable for the present invention may be one or more selected from the group consisting of ester solvents, alcohol solvents and ether solvents. Examples of the alcohol solvent include terpineol and butyl carbitol. Examples of the ester-based solvent include butyl carbitol acetate, ethylene glycol ethyl ether acetate, and 2,2, 4-trimethyl-1, 3-pentanediol monoisobutyrate (Texanol). In some embodiments, the organic solvent used in the present invention includes an alcohol solvent and an ester solvent, for example, including terpineol and butyl carbitol acetate, and the mass ratio of the two solvents may be (1-5): 1. for example, 2.7: 1. the organic solvent is generally used in an amount of 80wt% to 95wt%, such as 80wt% to 90wt%, 85wt% to 90wt%, 89wt%, based on the total weight of the organic vehicle.

Organic additives such as a dispersant, a defoaming agent, a lubricant, and a thixotropic agent may be added to the organic vehicle as needed. In some embodiments, the organic additive used in the present invention is soy lecithin. The organic additive is generally used in an amount of no more than 5wt% of the total weight of the organic vehicle. When included, the organic additive is preferably present in an amount of from 1wt% to 5wt%, for example 3wt%, based on the total weight of the organic vehicle.

In some embodiments, the organic vehicle comprises 80wt% to 90wt% of an organic solvent, 8wt% to 15wt% of a resin, and 1 to 5wt% of an organic additive, based on the total weight of the organic vehicle, wherein the organic solvent is a mixture of organic solvents and organic additives, and the organic solvent is a mixture of organic solvents in a mass ratio of 1: 1 to 5: 1 terpineol and butyl carbitol acetate, the resin is ethyl cellulose, and the organic additive is soybean lecithin.

The organic vehicle can be prepared by uniformly mixing the components of the organic vehicle, and if desired, heating (e.g., to 65-75 ℃ for mixing) can be performed while mixing. In some embodiments, the organic vehicle is prepared by first uniformly mixing the organic additive (e.g., soy lecithin) and a portion of the organic solvent (e.g., terpineol), then uniformly mixing the resulting mixture with the resin (e.g., ethyl cellulose), and finally uniformly mixing the resulting mixture with the remaining organic solvent (e.g., butyl carbitol acetate).

Light burned mullite and dolomite

The invention discovers that the simultaneous addition of a certain amount of light calcined mullite and dolomite to thick film resistor paste can reduce the size effect of chip resistors or thick film resistors prepared from the thick film resistor paste.

Mullite (Mullite) is a mineral with aluminosilicate as the major constituent. Al different from other kinds of mullite and light-burned mullite₂O₃The content is 67.5wt percent to 69wt percent,for example 68.2 wt%. The light-burned mullite may contain, based on the total mass of the light-burned mullite: 67.5-70 wt.%, e.g., 68.2 wt.% Al₂O₃24.5% to 26% by weight, for example 25.3% by weight, of SiO₂And 5wt% to 8wt%, e.g., 6.5wt% impurities. The impurities in the lightly calcined mullite include Fe₂O₃、TiO₂、CaO、MgO、K₂O and Na₂And O. The density of the light-burned mullite is 2.7-2.8g/cm³For example 2.75g/cm³. The calcined mullite is commercially available.

The chemical component of Dolomite (Dolomite) is CaMg (CO)₃)₂Trigonal crystal system. The crystal structure of dolomite is similar to that of calcite, the crystal form is rhombohedral, the crystal face is often bent into saddle shape, and the poly-lamellar twins are common and mostly present in block and granular aggregates. The density of dolomite is 2.8-2.9g/cm³. Dolomite can be purchased from commercial sources.

The total content of the soft-burned mullite and dolomite in the thick-film resistor paste of the present invention is preferably 5wt% to 15wt%, for example 5wt%, 6wt%, 7wt%, 8wt%, 9wt%, 10wt%, 11wt%, 12wt%, 13wt%, 14wt%, 15wt%, based on the total mass of the thick-film resistor paste. The mass ratio of the light-burned mullite to the dolomite is preferably 2: 1 to 1: 2, e.g. 1: 1. 1.5: 1. 2: 1. the mass ratio of the light-burned mullite to the dolomite is controlled in the range, which is beneficial to the light-burned mullite and the dolomite to play the role of reducing the size effect.

The particle size of the light-burned mullite and dolomite suitable for use in the present invention is preferably in the range 0.8 μm to 1.3. mu.m, for example 1 μm.

The invention includes the use of lightly calcined mullite and dolomite in the preparation of thick film resistor paste, the use of lightly calcined mullite and dolomite in reducing the dimensional effect of a chip resistor or thick film resistor, a method of reducing the dimensional effect of a chip resistor or thick film resistor, the use of lightly calcined mullite and dolomite in the preparation of thick film resistor paste with improved dimensional effect, and a method of preparing thick film resistor paste with improved dimensional effect. The use or method may be, for example, the addition of light-burned mullite and dolomite to a thick film resistor paste, or the further use of the thick film resistor paste to make a thick film resistor or chip resistor. The light-burned mullite and the dolomite, the using amount and the proportion of the light-burned mullite and the dolomite in the thick film resistor paste are as described in any embodiment of the invention. The thick film resistor paste is as described in any of the embodiments of the invention.

Additive agent

The thick-film resistor paste of the present invention may further comprise additives commonly used in thick-film resistor pastes. The additive in the thick film resistor paste means a material for adjusting resistance properties in addition to the functional phase and the glass binder phase, including a material for controlling resistance, temperature coefficient, pattern retention, adjusting sintering characteristics, improving temperature sensitivity, enhancing weather resistance, etc. Unlike the organic additives in the organic vehicle, the additives are typically inorganic and may be, for example, one or more selected from elemental metals, metal oxides, non-metal oxides, metal nitrides, metal fluorides, and silicates. The additive may be present in the thick film resistor paste of the present invention in an amount of 0 to 5wt%, for example 1wt% to 5wt%, 3wt%, based on the total mass of the thick film resistor paste.

Additives suitable for use in the thick film resistor paste of the present invention may include those selected from the group consisting of elemental copper, copper-containing compounds, elemental manganese, manganese-containing compounds, elemental tantalum, tantalum-containing compounds, and Nb₂O₅And Sb₂O₃One or more of (a). In some embodiments, the additives in the thick film resistor paste include CuO and MnO₂Or from CuO and MnO₂The mass ratio of the two components can be 1: 2 to 2: 1, e.g. 1: 1. CuO and MnO₂For adjusting the resistance value and the temperature coefficient.

In the present invention, the particle size of the additive is preferably 1 μm to 2 μm, for example 1.5. mu.m.

Thick film resistor paste, chip resistor, thick film resistor and circuit board

The thick film resistor paste of the invention can be prepared by the following method: uniformly mixing the functional phase, the glass bonding phase, the organic carrier, the light-burned mullite, the dolomite and optional additives, and rolling by using a three-roll mill to obtain slurry; preferably, the roller is rolled to the fineness of less than or equal to 5 mu m. The composition and content of the components in the thick film resistor paste may be as described in any of the previous embodiments.

The thick film resistor paste of the present invention has a reduced dimensional effect due to the inclusion of a certain amount of light-burned mullite and dolomite, as evidenced by the fact that the resistivity of the chip resistor or the thick film resistor does not change significantly or remains substantially unchanged when the thick film resistor paste of the present invention is fabricated into chip resistors or thick film resistors of different specifications (dimensions).

In some embodiments, the thick film resistor paste of the present invention comprises or consists of 15wt% to 45wt% of a functional material, 10wt% to 40wt% of a glass frit, 5wt% to 15wt% in total of a light-burned mullite and a dolomite, 30wt% to 45wt% of an organic vehicle, and 1wt% to 5wt% of an additive, wherein the functional material may include one or more selected from the group consisting of silver powder, palladium powder, ruthenium dioxide, and lead ruthenate, and the glass frit may include, in a mass ratio of 1: 4 to 4: 1, the mass ratio of Pb-B-Ca-Si system glass powder to Pb-B-Si system glass powder to the light-burned mullite to the dolomite is preferably 2: 1 to 1: 2.

the invention comprises a thick film resistor and a chip resistor prepared from the thick film resistor paste. In the invention, the thick film resistor can be prepared by printing thick film resistor paste on a substrate, drying and sintering. The chip resistor comprises a substrate, a resistive film, a protective film and electrodes, wherein the resistive film is formed by printing thick film resistor paste on the substrate, drying and sintering. The drying temperature may be 150 + -10 deg.C. The drying time may be 10. + -.2 min. The peak temperature of sintering may be 850 + -10 deg.C, preferably 850 + -5 deg.C. The holding time at the peak temperature may be 10 ± 2 min. The sintering period may be 60 + -5 min. The apparatus for sintering may be a strand sintering furnace.

The thick film resistor and the chip resistor prepared by the thick film resistor paste have the following properties:

a resistivity that does not substantially vary with a dimensional change of the resistor, for example, a resistance pattern of 0.2mm x 0.2mm of the same thickness has an absolute value of a rate of change of resistance of not more than 10%, preferably not more than 3%, as compared with a resistance pattern of 1.5mm x 1.5 mm;

the electrostatic discharge resistance is excellent, and the absolute value of the resistance value change rate before and after receiving 3kV electrostatic pulse impact is not more than 0.5 percent, preferably not more than 0.2 percent;

excellent temperature coefficient performance, positive temperature coefficient (HTCR) at 25 ℃ to 125 ℃ and negative temperature coefficient (CTCR) at 25 ℃ to-55 ℃ having absolute values not exceeding 100 ppm/DEG C.

The invention includes circuit boards comprising the thick film resistors of the invention. The circuit board of the invention comprises a substrate and a thick film resistor formed on the substrate. The thick film resistor is formed by sintering the thick film resistor paste.

The invention also includes the use of the thick film resistor paste of the invention for the preparation of thick film resistors or chip resistors with reduced dimensional effects, and for the preparation of circuit boards containing said thick film resistors.

The invention has the following advantages:

according to the invention, the light-burned mullite and the dolomite are added into the thick film resistor paste together, so that the problems of large size effect and narrow application range of the traditional thick film resistor paste are solved;

the thick film resistor paste has the advantages of simple preparation process, strong process adaptability and small size effect.

The present invention is described in detail below with reference to specific examples, which do not limit the scope of the present invention. The scope of the present invention is defined only by the appended claims, and any omissions, substitutions, and changes in the form of the embodiments disclosed herein that may be made by those skilled in the art are intended to be included within the scope of the present invention.

The following examples use instrumentation conventional in the art. The experimental procedures, in which specific conditions are not noted in the following examples, are generally carried out under conventional conditions or conditions recommended by the manufacturers. In the following examples, various starting materials were used, unless otherwise specified, in conventional commercial products, the specifications of which are those commonly used in the art. In the description of the present invention and the following examples, "%" represents weight percent, "parts" represents parts by weight, and proportions represent weight ratios, unless otherwise specified.

In the following examples and comparative examples, the particle size of the silver powder was2 μm, the average specific surface area of the palladium powder is 10m²A ruthenium dioxide average specific surface area of 40m²Per g, lead ruthenate has an average specific surface area of 6m²The grain size of the light calcined mullite is 1 mu m, and the grain size of the dolomite is 1 mu m.

Preparation example 1: preparation of glass powder

The raw material of the glass powder A is 45wt% of Pb₃O₄28wt% of CaO, 23wt% of SiO₂And 4wt% of B₂O₃The raw material of the glass powder B is 65wt% of Pb₃O₄20% by weight of SiO₂And 15wt% of B₂O₃Uniformly mixing glass powder raw materials, putting the obtained mixture into a 1350 ℃ smelting furnace for smelting, keeping the temperature for 1.5h, performing water quenching on the obtained glass solution to obtain glass, crushing the glass into glass slag, grinding the glass slag into particles with the particle size of 1.5 mu m by using a ball mill, and drying to obtain glass powder A and glass powder B.

Preparation example 2: preparation of the additives

CuO and MnO with a particle size of 1.5 μm₂According to the mass ratio of 1: 1 as additives used in examples 1-6 and comparative examples 1-6.

Preparation example 3: preparation of organic vehicle

65g of terpineol and 3g of soybean lecithin were stirred in a beaker and heated to 70 ℃, 8g of ethyl cellulose was added and stirred continuously to dissolve completely, 24g of butyl carbitol acetate was added and stirred for 30 minutes at a constant temperature, to obtain the organic vehicle used in examples 1 to 6 and comparative examples 1 to 6.

Example 1

According to the weight portion ratio in table 1, silver powder, palladium powder, ruthenium dioxide, glass powder a, glass powder B, an additive, light-burned mullite, dolomite and an organic carrier are uniformly mixed, and then fully ground by a three-roll mill until the fineness is less than 5 μm, so as to prepare the resistance paste of example 1.

Example 2

According to the weight part ratio in table 1, ruthenium dioxide, lead ruthenate, glass powder a, glass powder B, an additive, light-burned mullite, dolomite and an organic carrier are uniformly mixed, and then sufficiently ground by a three-roll mill until the fineness is less than 5 μm, so as to prepare the resistance paste of example 2.

Example 3

According to the weight part ratio in table 1, lead ruthenate, glass powder a, glass powder B, additive, light-burned mullite, dolomite and organic carrier are uniformly mixed, and then fully ground by a three-roll mill until the fineness is less than 5 μm, so as to prepare the resistance paste of example 3.

Example 4

According to the weight part ratio in table 1, ruthenium dioxide, lead ruthenate, glass powder a, glass powder B, an additive, light-burned mullite, dolomite and an organic carrier are uniformly mixed, and then sufficiently ground by a three-roll mill until the fineness is less than 5 μm, so as to prepare the resistance paste of example 4.

Example 5

According to the weight part ratio in table 1, ruthenium dioxide, lead ruthenate, glass powder a, glass powder B, an additive, light-burned mullite, dolomite and an organic carrier are uniformly mixed, and then sufficiently ground by a three-roll mill until the fineness is less than 5 μm, so as to prepare the resistance paste of example 5.

Example 6

Ruthenium dioxide, lead ruthenate, glass powder A, glass powder B, an additive, light-burned mullite, dolomite and an organic carrier are uniformly mixed according to the weight part ratio in Table 1, and then fully ground by a three-roll mill until the fineness is less than 5 μm, so that the resistance paste of the embodiment 6 is prepared.

Comparative example 1

According to the weight portion ratio in table 2, after uniformly mixing silver powder, palladium powder, ruthenium dioxide, glass powder a, glass powder B, an additive and an organic carrier, fully grinding the mixture by a three-roll mill until the fineness is less than 5 μm, and preparing the resistance paste of the comparative example 1.

Comparative example 2

According to the weight portion ratio in table 2, ruthenium dioxide, lead ruthenate, glass powder A, glass powder B, additives and organic carriers are uniformly mixed, and then fully ground by a three-roll mill until the fineness is less than 5 μm, so as to prepare the resistance paste of comparative example 2.

Comparative example 3

According to the weight portion ratio in table 2, lead ruthenate, glass powder A, glass powder B, additive and organic carrier are uniformly mixed, and then fully ground by a three-roll mill until the fineness is less than 5 μm, so as to prepare the resistance paste of comparative example 3.

Comparative example 4

According to the weight portion ratio in table 2, ruthenium dioxide, lead ruthenate, glass powder a, glass powder B, additives, alumina, silica, calcium carbonate, magnesium carbonate and organic carriers were uniformly mixed, and then sufficiently ground by a three-roll mill until the fineness was less than 5 μm, to prepare the resistance paste of comparative example 4.

Comparative example 5

According to the weight portion ratio in table 2, ruthenium dioxide, lead ruthenate, glass powder A, glass powder B, additives, calcium carbonate, magnesium carbonate, light-burned mullite and an organic carrier are uniformly mixed, and then fully ground by a three-roll mill until the fineness is less than 5 μm, so that the resistance paste of the comparative example 5 is prepared.

Comparative example 6

According to the weight part ratio in table 2, ruthenium dioxide, lead ruthenate, glass powder A, glass powder B, additive, alumina, silica, dolomite and organic carrier are uniformly mixed, and then fully ground by a three-roll mill until the fineness is less than 5 μm, so as to prepare the resistance paste of the comparative example 6.

Table 1: formulation of resistance pastes of examples 1 to 6 (unit: parts by mass)

Table 2: formulation of resistance pastes of comparative examples 1 to 6 (unit: parts by mass)

Test example

The resistance pastes of examples 1 to 6 and comparative examples 1 to 6 were respectively printed by screen printing with thick film resistance patterns of 0.2mm × 0.2mm, 0.3mm × 0.3mm, 0.5mm × 0.5mm, 0.8mm × 0.8mm, 1.2mm × 1.2mm, 1.5mm × 1.5mm, dried at 150 ℃ for 10min, sintered at 850 ℃ in a belt sintering furnace with a sintering cycle of 60min and a peak temperature held for 10min to prepare test samples, and the following tests were carried out with the results as shown in tables 3 and 4:

and (3) testing the size effect: testing resistance values R of different sizes, wherein after the resistance paste is printed into different sizes, the resistance value consistency is better, and the size effect is lower;

and (3) electrostatic discharge testing: and testing the change rate of the resistance value of the resistor body after the electrostatic impact is passed for determining the electrostatic impact resistance of the resistor in use, wherein the change rate of the resistance value is close to zero, and the resistance slurry has better performance. According to a resistance electrostatic discharge test method 302 in an electronic paste performance test method for an SJ/T11512-2015 integrated circuit, testing the resistance R1 of a resistor with a resistor pattern of 0.8mm multiplied by 0.8mm, performing 3kV electrostatic pulse impact on the resistor with the resistor pattern of 0.8mm multiplied by 0.8mm, then testing the resistance R2 of the resistor, and calculating the resistance change rate (delta R = (R2-R1)/R1) before and after pulse voltage;

temperature Coefficient (TCR) test: the resistance values of the resistor of 0.8mm × 0.8mm resistance pattern at 25 deg.C, 125 deg.C and-55 deg.C were tested according to the method 301 temperature coefficient of resistance paste (TCR) test method in the test method for the performance of electronic paste for SJ/T11512-2015 integrated circuit. The resistance change rate at 25 ℃ to 125 ℃ per 1 ℃ change is the positive temperature coefficient (HTCR), and the resistance change rate at 25 ℃ to-55 ℃ per 1 ℃ change is the negative temperature coefficient (CTCR). The temperature coefficient of the conventional resistance paste ranges from-100 ppm/DEG C to +100 ppm/DEG C.

Table 3: properties of resistors made from the resistor pastes of examples 1-6

Table 4: properties of resistors made from the resistor pastes of comparative examples 1-6

As can be seen from tables 3 and 4, when the examples 1 to 3 of the present invention are compared with the comparative examples 1 to 3, it can be found that after the light calcined mullite and dolomite are introduced into the slurry formulation, the resistance uniformity of the resistance paste is significantly improved after the resistance paste is printed in different sizes, and the electrostatic discharge and temperature coefficient characteristics of the paste are not deteriorated.

Comparing example 2 of the present invention with comparative example 4, it can be seen that the addition of the lightly calcined mullite and dolomite into the resistance paste by replacing them with the corresponding oxides and carbonates has no effect on the size effect. Comparing example 2 of the present invention with comparative examples 5 and 6, it can be seen that the addition of the lightly calcined mullite or dolomite alone to the electrical resistance paste has no effect on the size effect, indicating that the combined action of the lightly calcined mullite and dolomite exerts the effect of reducing the size effect.

It can be found from examples 4 to 6 of the present invention that the effect of improving the size effect is relatively weak when the content of the lightly calcined mullite and dolomite is less, and the electrostatic discharge performance of the resistor paste tends to be deteriorated when the content is too high, but the size effect of the resistor paste is significantly improved within the scope of the present invention.