CN114930467A - Conductive paste, electrode, and chip resistor - Google Patents
Conductive paste, electrode, and chip resistor Download PDFInfo
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- CN114930467A CN114930467A CN202180009442.0A CN202180009442A CN114930467A CN 114930467 A CN114930467 A CN 114930467A CN 202180009442 A CN202180009442 A CN 202180009442A CN 114930467 A CN114930467 A CN 114930467A
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
- H01B1/00—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors
- H01B1/20—Conductive material dispersed in non-conductive organic material
- H01B1/22—Conductive material dispersed in non-conductive organic material the conductive material comprising metals or alloys
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01C—RESISTORS
- H01C1/00—Details
- H01C1/14—Terminals or tapping points or electrodes specially adapted for resistors; Arrangements of terminals or tapping points or electrodes on resistors
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01C—RESISTORS
- H01C7/00—Non-adjustable resistors formed as one or more layers or coatings; Non-adjustable resistors made from powdered conducting material or powdered semi-conducting material with or without insulating material
Abstract
Provided is a conductive paste which can form an electrode having high resistance to vulcanization, low resistance, and relatively low cost. The conductive paste contains (A) alloy particles containing Ag and Sn, (B) a glass frit, and (C) a thermoplastic resin, wherein the weight ratio of Sn in the alloy particles (A) is less than 10 wt%.
Description
Technical Field
The present invention relates to a conductive paste used for forming an electrode of an electronic component, for example. The present invention also relates to an electrode formed using the conductive paste, and a chip resistor having the electrode.
Background
A conductive paste containing silver powder is used for forming electrodes of a chip resistor, which is one of electronic components. Fig. 1 shows an example of a cross-sectional structure of the chip resistor 100. The chip resistor 100 has a rectangular alumina substrate 102, and is formed on the upper surface of the alumina substrate 102: a resistor body 104; and an extraction electrode 106 for extracting electricity from the resistor 104. Further, on the lower surface of the alumina substrate 102 are formed: and a lower surface electrode 108 for mounting the chip resistor 100 to a substrate. Further, a connection electrode 110 for connecting the extraction electrode 106 and the lower surface electrode 108 is formed on an end surface of the alumina substrate 102. The top surface and the bottom surface of the alumina substrate 102 are coated with a conductive paste by printing, and then fired to form the extraction electrode 106 and the bottom surface electrode 108, respectively. Generally, a nickel plating film 112 and a tin plating film 114 are formed on the extraction electrode 106, the lower surface electrode 108, and the connection electrode 110.
The extraction electrode 106 and the lower surface electrode 108 are generally formed using different conductive pastes because they have different characteristics required for each. For example, in the formation of the extraction electrode 106, a conductive paste having good matching properties with the resistor 104 is used. When the resistance value of the resistor 104 is low, the resistance value of the extraction electrode 106 is also required to be low. For this reason, a conductive paste capable of forming a low-resistance electrode is used for forming the extraction electrode 106.
Conventionally, as a conductive paste used for forming an electrode, a conductive paste containing a silver powder and a glass frit, which is disclosed in patent documents 1 and 2, has been known.
Documents of the prior art
Patent literature
Patent document 1: JP-A7-105723
Patent document 2: JP 2016-538708
Disclosure of Invention
In automobiles, thermal power stations, and the like, fossil fuels are burned, and sulfur oxides are discharged in large quantities into the atmosphere. In addition, in sewage treatment plants, garbage treatment plants, and the like, sulfur is also reduced by anaerobic bacteria to generate hydrogen sulfide. Therefore, sulfur-containing components such as sulfur oxide and hydrogen sulfide exist in the atmosphere.
When sulfur components in the atmosphere reach the surface of silver, the sulfur components adhere to the surface of silver and react with silver to form silver sulfide. For example, in an electrode made of silver as a main material, such as an electrode of a chip resistor, the same reaction occurs, and therefore, the silver inside the electrode may be silver sulfide. When silver sulfide is generated in the electrode, the electrode may be broken. Therefore, in devices such as chip resistors having electrodes made of silver, malfunction may occur. Such a phenomenon is called disconnection due to vulcanization.
In order to suppress the disconnection due to the vulcanization, an electrode made of silver as a main material used for a device such as a chip resistor needs to have high resistance to the vulcanization.
In order to suppress the disconnection due to the vulcanization, a palladium monomer or palladium added in a predetermined amount (for example, about 20 wt%) is proposed as the conductive particles of the conductive paste for forming the electrode. However, since palladium is expensive, there is a problem that the cost of the conductive paste is increased by the addition of a palladium monomer or palladium.
Accordingly, an object of the present invention is to provide a conductive paste capable of forming an electrode having high resistance to vulcanization and low resistance at a relatively low cost.
In order to solve the above problems, the present invention has the following configuration.
(Structure 1)
Structure 1 of the present invention is a conductive paste containing: (A) alloy particles containing Ag and Sn; (B) a glass frit; and (C) a thermoplastic resin, wherein the weight ratio of Sn in the alloy particles (A) is less than 10 wt%.
(Structure 2)
In structure 2 of the present invention, the weight ratio of Ag in the alloy particles (a) is 50 wt% or more based on the conductive paste of structure 1.
(Structure 3)
In the structure 3 of the present invention, the content of the glass frit (B) is 2 to 20 parts by weight based on 100 parts by weight of the alloy particles (a) in the conductive paste of the structure 1 or 2.
(Structure 4)
Structure 4 of the present invention is the conductive paste according to any one of structures 1 to 3, further comprising: (D) a silica filler.
(Structure 5)
Structure 5 of the present invention is the conductive paste of structure 4, wherein the glass frit (B) contains SiO 2 And TiO 2 SiO contained in the glass frit of (B) 2 Of (B) and SiO contained in the silica filler (D) 2 The weight ratio of (A) to (B) is 1: 0.25 to 1: 9.8.
(Structure 6)
Structure 6 of the present invention is an electrode obtained by firing the conductive paste described in any one of structures 1 to 5.
(Structure 7)
Structure 7 of the present invention is a chip resistor having the electrodes described in structure 6.
According to the present invention, a conductive paste capable of forming an electrode having high resistance to vulcanization, low resistance, and relatively low cost can be provided.
Drawings
Fig. 1 is a schematic diagram showing an example of a cross-sectional structure of a chip resistor.
Fig. 2 is an SEM photograph (magnification 1500 times) of a cross section of a sintered body near the surface thereof after storing a test piece (sintered body of conductive paste) produced under the same conditions as in example 4 in a sulfur-containing gas atmosphere.
Fig. 3 is an SEM photograph (magnification 1500 times) of a cross section of the vicinity of the surface of a fired body after storing a test piece (fired body of conductive paste) produced under the same conditions as in comparative example 3 in a sulfur-containing gas atmosphere.
Detailed Description
The embodiments of the present invention are specifically described below. The following embodiments are embodiments of the present invention, and the present invention is not limited to these embodiments.
The conductive paste of the present embodiment includes (a) alloy particles, (B) glass frit, and (C) thermoplastic resin. The conductive paste of the present embodiment can be preferably used for forming an electrode of a device such as a chip resistor having an electrode made of silver as a material.
The components contained in the conductive paste of the present embodiment are described below.
(A) Alloy particles
The conductive paste of the present embodiment contains (a) alloy particles. (A) The alloy particles include silver (Ag) and tin (Sn). The alloy particles (a) contain Sn, whereby sulfidation of Ag can be suppressed. Therefore, by using the conductive paste of the present embodiment, an electrode having high sulfidation resistance can be formed.
The alloy particles (a) may contain metals other than Ag and Sn. However, in order to reliably obtain an electrode having low resistance and high sulfidation resistance, the alloy particles (a) preferably contain only Ag and Sn. In the present specification, the phrase "(a) alloy particles contain only Ag and Sn" means that metals other than Ag and Sn are not intentionally added as (a) metal particles, and that the metal particles are excluded from containing the inevitably mixed metals other than Ag and Sn.
(A) The alloy particles may contain metals such as Zn, In, Al, and Si as metals other than Ag and Sn within a range not impairing the effects of the present embodiment.
In the conductive paste of the present embodiment, the weight ratio of Sn in the (a) alloy particles is preferably less than 10 wt%. More specifically, the weight ratio of Sn in the (a) alloy particles is preferably 1 wt% or more and less than 10 wt%, more preferably 1.5 wt% or more and less than 9 wt%, further preferably 2 wt% or more and less than 8 wt%, and particularly preferably 4 wt% or more and less than 8 wt%. When the weight ratio of Sn is too large, the resistance as an electrode may become too high. In addition, when the weight ratio of Sn is small, the improvement of the sulfidation resistance may be small. Particularly, when the weight ratio of Sn is less than 2 wt%, the sulfidation resistance may be easily deteriorated.
In the conductive paste of the present embodiment, the weight ratio of Ag in the (a) alloy particles is preferably 50 wt% or more, more preferably 70 wt% or more, and still more preferably more than 90 wt%. Ag has a lower resistance than other metals. Therefore, when the weight ratio of Ag is in a predetermined range, an electrode having a relatively low resistance can be obtained.
(A) The shape of the alloy particles is not particularly limited, and for example, spherical, granular, snow-flake and/or scale-like alloy particles can be used.
(A) The average particle diameter of the alloy particles is preferably 0.1 to 10 μm, more preferably 0.1 to 7 μm, and most preferably 1 to 5 μm. The average particle diameter referred to herein means a volume-based median diameter (D50) obtained by laser diffraction scattering particle size distribution measurement.
(A) The method for producing the alloy particles is not particularly limited, and the alloy particles can be produced by, for example, a reduction method, a pulverization method, an electrolysis method, an atomization method, a heat treatment method, or a combination thereof. The snowflake-like alloy particles can be produced by, for example, crushing spherical or granular alloy particles with a ball mill or the like.
(B) Glass frit
The conductive paste of the present embodiment contains (B) a glass frit.
(B) The glass frit preferably comprises SiO 2 And TiO 2 . When the conductive paste contains the glass frit (B), the adhesion strength of the electrode obtained by firing the conductive paste to the substrate is improved. The glass frit is not particularly limited, and a glass frit having a softening point of 300 ℃ or higher can be preferably used, more preferably a glass frit having a softening point of 400 to 900 ℃, and still more preferably a glass frit having a softening point of 500 to 800 ℃. The softening point of the glass frit can be measured using a thermogravimetric apparatus (e.g., TG-DTA2000SA, manufactured by BRUKERAXS).
An example of the glass frit (B) is titanium borosilicate (TiO) 2 Series) and borosilicate barium series. Examples of the glass frits include bismuth borosilicate series, alkali metal borosilicate series, rare earth borosilicate series, zinc borosilicate series, lead borate series, lead silicate series, bismuth borate series, zinc borate series, and the like. These glass frits can also be used in combination of 2 or more. The frit is preferably lead-free for environmental reasons.
The glass frit preferably comprises ZnO, BaO, Na 2 O, CaO and Al 2 O 3 At least 1 selected from the group consisting of. More preferably, the glass frit contains ZnO, BaO and Na 2 O and Al 2 O 3 。
The average particle size of the glass frit is preferably 0.1 to 20 μm, more preferably 0.2 to 10 μm, and most preferably 0.5 to 5 μm. The average particle diameter referred to herein means a volume-based median diameter (D50) obtained by laser diffraction scattering particle size distribution measurement.
In the conductive paste of the present embodiment, the content of the glass frit (B) is preferably 1 to 20 parts by weight, more preferably 1.5 to 15 parts by weight, and still more preferably 2 to 10 parts by weight, based on 100 parts by weight of the alloy particles (a). When the content of the glass frit is less than this range, the adhesion of the electrode obtained by firing the conductive paste to the substrate is lowered. When the content of the glass frit is more than this range, the resistance value of the electrode obtained by firing the conductive paste becomes high. In addition, when the content of the glass frit is relatively small, an electrode having a low resistance can be obtained. In addition, when the content of the glass frit is relatively large, an electrode having excellent chemical resistance can be obtained. Chemical resistance is a characteristic required for performing a plating pretreatment when a plating film is formed on the surface of an electrode. The pretreatment for plating is performed to remove contaminants from the surface of the electrode, activate the surface of the electrode, and bring the electrode into a clean state suitable for plating. The contaminants to be removed are roughly classified into organic and inorganic contaminants. The pretreatment step is not a step of removing all contaminants in a single step. For example, organic substances are removed in a process using an alkaline detergent. The inorganic substance is removed in the step of using an acid-based detergent. Therefore, the electrode is required to have high chemical resistance.
The conductive paste softens the glass frit with an increase in temperature, and silver sintering progresses. When the glass frit content is large, the glass component may be extruded to the surface of the sintered body. In this case, the surface of the sintered body may be covered with a glass component. By forming the nickel plating film on the surface of the sintered body, not only can the diffusion of tin from the tin plating film to the electrode be suppressed, but also the conductivity of the sintered body can be improved in the case where the surface of the sintered body is covered with the glass component. The alloy particles (a) of the present embodiment are alloy particles containing Ag and Sn, and therefore have lower sinterability than Ag particles. Therefore, the occurrence of a phenomenon in which the surface of the sintered body is covered with a glass component can be suppressed. Therefore, the content of the glass frit can be increased, and thus an electrode having excellent chemical resistance can be obtained as compared with Ag particles. In addition, since the content of the (D) silica filler having the same properties and functions as those of the glass frit can be increased, an electrode having excellent chemical resistance can be obtained.
(C) Thermoplastic resin
The conductive paste of the present embodiment contains (C) a thermoplastic resin.
The thermoplastic resin connects the silver powders to each other in the conductive paste. As the thermoplastic resin, a thermoplastic resin that is burned off at the time of firing of the conductive paste can be used.
Examples of the thermoplastic resin include cellulose resins such as ethyl cellulose and nitrocellulose, acrylic resins, alkyd resins, saturated polyester resins, butyral resins, polyvinyl alcohol, and hydroxypropyl cellulose. These resins may be used alone or in combination of 2 or more.
(C) The content of the thermoplastic resin is preferably 0.5 to 40 parts by weight, more preferably 1 to 35 parts by weight, based on 100 parts by weight of the alloy particles (A). When the content of the thermoplastic resin in the conductive paste is within the above range, the conductive paste has improved coatability to the substrate and paste leveling property, and the printed shape is excellent. On the other hand, if the content of the thermoplastic resin exceeds the above range, the amount of the thermoplastic resin contained in the conductive paste becomes excessive. For this reason, it is possible that the electrode cannot be formed with high accuracy any more.
(D) Silica filler
The conductive paste of the present embodiment preferably further contains (D) a silica filler.
(D) As the silica filler, for example, commercially available spherical Silica (SiO) 2 ) The particles are used as a semiconductor sealing material. The shape of the silica filler may be other than spherical. The method for producing the silica filler is not particularly limitedA silica filler produced by a known method such as a thermal spray method can be used. The average particle diameter of the silica filler is preferably 20nm to 5 μm, and more preferably 1 μm to 3 μm. The average particle diameter referred to herein means a volume-based median diameter (D50) obtained by laser diffraction scattering particle size distribution measurement.
In the conductive paste of the present embodiment, (B) the glass frit contains SiO 2 And TiO 2 (B) SiO contained in the glass frit 2 Weight B of (A) and (D) SiO contained in the silica filler 2 The weight ratio of (A) to (B) is preferably 1: 0.25 to 1: 9.8, and preferably 1: 0.25 to 1: 3.5.
The conductive paste of the present embodiment contains (D) a silica filler, and thus the chemical resistance of the obtained electrode is improved. On the other hand, when the silica filler is excessively large, the resistance value of the obtained electrode becomes high, and it is difficult to obtain a low-resistance electrode. The silica filler (D) has the same function as the glass frit (B). For this purpose, the SiO contained in the glass frit is used as (B) 2 Weight B of (D) SiO contained in the silica filler 2 The ratio of the weight D of (A) is in the above-mentioned range, and an electrode having a suitable chemical resistance and a low resistance can be obtained.
(E) Solvent(s)
The conductive paste of the present embodiment may contain (E) a solvent. Examples of the solvent include alcohols such as methanol, ethanol and isopropyl alcohol (IPA), organic acids such as vinyl acetate, aromatic hydrocarbons such as toluene and xylene, N-alkylpyrrolidones such as N-methyl-2-pyrrolidone (NMP), amides such as N, N-Dimethylformamide (DMF), ketones such as Methyl Ethyl Ketone (MEK), cyclic carbonates such as Terpineol (TEL) and Butyl Carbitol (BC), and water. The content of the solvent is not particularly limited. The content of the solvent is preferably 1 to 100 parts by weight, more preferably 5 to 60 parts by weight, based on 100 parts by weight of the alloy particles (A).
The viscosity of the conductive paste of the present embodiment is preferably 50 to 700Pa · s (shear rate: 4.0 sec) -1 ) More preferably 100 to 300 pas (shear rate: 4.0sec -1 ). By adjusting the viscosity of the conductive paste to be within this range, the conductive paste can be applied to the substrate with good applicability and good handling properties, and the conductive paste can be applied to the substrate with a uniform thickness. The viscosity of the conductive paste can be measured by using a model HB viscometer SC4-14SPINDLE (Brookfield corporation).
The conductive paste of the present embodiment may contain other additives such as a dispersant, a rheology modifier, and a pigment.
The conductive paste of the present embodiment can be produced by mixing the above-described components using a kneader, a can mill, a three-roll mill, a rotary mixer, a biaxial mixer, or the like.
The present embodiment is an electrode obtained by firing the conductive paste of the present embodiment described above.
The present embodiment is an electrode formed using the conductive paste of the present embodiment as a material. The electrode of the present embodiment is obtained by applying a conductive paste to a substrate and firing the paste. Therefore, the electrode of the present embodiment can contain (a ') alloy particles containing Ag and Sn and (B') glass component using glass frit as a material. (A') the alloy particles are in a sintered state. The weight ratio of Sn in the (a') alloy particles of the electrode of the present embodiment is less than 10% by weight. The thermoplastic resin (C) and the solvent (E) contained in the conductive paste are vaporized or burned at the time of firing, and therefore the electrode does not substantially contain the thermoplastic resin (C) and the solvent (E).
The electrode of the present embodiment may further contain (D ') a silica filler in addition to the (a ') alloy particles and the (B ') glass component. In the electrode of the present embodiment, the weight ratio of Ag in the (a ') alloy particles, the content of the (B ') glass component, and the composition of the (B ') glass component correspond to the weight ratio and composition of the (a) alloy particles and the (B) glass frit contained in the conductive paste serving as the material.
The sheet resistance of the thin film to be the electrode of the present embodiment can be approximately 10m Ω/□ (10m Ω/square) or 10m Ω/□ or less, depending on the film thickness. For this reason, it can be preferably used for forming an electrode which is required to have low resistance.
Next, a method of forming an electrode on a substrate using the conductive paste of the present embodiment will be described. First, a conductive paste is applied to a substrate. The coating method is arbitrary, and for example, coating can be performed by a known method such as dispensing, jet dispensing, stencil printing, screen printing, pin transfer, or stamp.
After the conductive paste is applied to the substrate, the substrate is put into a firing furnace or the like. Then, the conductive paste applied to the substrate is fired at 500 to 900 ℃, preferably 600 to 900 ℃, and more preferably 700 to 900 ℃. Thus, the solvent component contained in the conductive paste is evaporated at 300 ℃ or lower, and the resin component is burned at 400 to 600 ℃ to form a fired body of the conductive paste. The electrode thus obtained has high chemical resistance and excellent adhesion to a substrate.
The present embodiment is a chip resistor having the above-described electrodes.
The conductive paste of the present embodiment can be used for formation of a circuit of a device such as an electronic component, formation of an electrode, bonding of a device such as an electronic component to a substrate, and the like. The conductive paste of the present embodiment can be preferably used for forming electrodes of a chip resistor.
Fig. 1 shows an example of a cross-sectional structure of a chip resistor 100 according to the present embodiment. The chip resistor 100 can have: a rectangular alumina substrate 102; and a resistor 104 and a lead-out electrode 106 disposed on the surface of the alumina substrate 102. The extraction electrode 106 is an electrode for extracting electricity from the resistor 104. Further, a lower surface electrode 108 for mounting the chip resistor 100 to a substrate can be disposed on the lower surface of the alumina substrate 102. Further, a connection electrode 110 for connecting the extraction electrode 106 and the lower surface electrode 108 can be disposed on an end surface of the alumina substrate 102. At least 1 of the extraction electrode 106, the lower surface electrode 108, and the connection electrode 110 can be formed using the conductive paste of the present embodiment. In particular, the extraction electrode 106 is preferably formed using the conductive paste of the present embodiment. Further, a nickel plating film 112 and a tin plating film 114 may be disposed on the upper surfaces (the surfaces on the opposite side from the alumina substrate 102) of the extraction electrode 106, the lower surface electrode 108, and the connection electrode 110.
By using the conductive paste of the present embodiment, an electrode having high resistance to vulcanization, low resistance, and relatively low cost can be formed, and thus an electronic device such as a chip resistor in which a highly reliable electrode is formed can be obtained.
Examples
The present invention will be specifically described below with reference to examples, but the present invention is not limited thereto.
[ preparation of conductive paste ]
The following components (a) to (E) were mixed in the proportions shown in tables 1 and 2 to prepare conductive pastes. The proportions of the components shown in tables 1 and 2 are all shown in parts by weight. The average particle diameter refers to a volume-based median diameter (D50) obtained by laser diffraction scattering particle size distribution measurement.
(A) Metal particles
As the metal particles (a), the following metal particles a1 to a7 were used. The following values of Ag/Sn are weight ratios.
Metal particles a1 (alloy particles): the weight ratio Ag/Sn was 98/2, and the average particle diameter (D50) was 2.5. mu.m.
Metal particles a2 (alloy particles): 95/5 weight ratio Ag/Sn, 2.5 μm average particle diameter (D50)
Metal particles a3 (alloy particles): the weight ratio Ag/Sn was 93/7, and the average particle diameter (D50) was 2.5. mu.m
Metal particles a 4: ag particles having an average particle diameter (D50) of 2.5 μm
Metal particles a 5: the weight ratio of Ag particles/Sn particles (93/7) was 2.5 μm for the mixture of Ag particles (average particle diameter (D50)2.5 μm) and Sn particles (average particle diameter (D50)2.5 μm)
Metal particles a6 (alloy particles): the weight ratio Ag/Sn was 90/10, and the average particle diameter (D50) was 2.5. mu.m
Metal particles a7 (alloy particles): 70/30 weight ratio Ag/Sn, 2.5 μm average particle diameter (D50)
(B) Glass frit
As the glass frit (B), the following glass frits B1 and B2 were used.
Glass frit B1: titanium borosilicate glass frit (composition of components: SiO) 2 -B 2 O 3 -Na 2 O-TiO 2 System), softening point (Ts) of 570 ℃ and average particle diameter (D50) of 1.4 μm
Glass frit B2: barium borosilicate glass frit (composition of components: SiO) 2 -B 2 O 3 -BaO series), softening point (Ts) 750 ℃, average particle diameter (D50)1.2 μm
(C) Thermoplastic resin
Thermoplastic resin C1: ethyl cellulose resin (STD-200, product of Dow chemical Co., Ltd.)
Thermoplastic resin C2: ethyl cellulose resin (STD-4, product of Dow chemical Co., Ltd.)
(D) Silica filler
As the silica filler (D), the following silica fillers were used.
Spherical Silica (SiO) 2 ) Powder, average particle diameter (D50)2 μm
(E) Solvent(s)
As the solvent, Texanol (manufactured by eastman chemical co., ltd.) was used.
[ preparation of test piece ]
Using the prepared conductive paste, a test piece was produced by the following procedure. First, a conductive paste was applied by screen printing on a20 mm × 20mm × 1mm (t) alumina substrate. Thus, 20 patterns each having a square pad shape with a side of 1.5mm were formed on the alumina substrate. A 250 mesh mask made of stainless steel was used in the formation of the pattern. Next, the conductive paste was dried at 150 ℃ for 10 minutes using a heat-seal dryer. After drying the conductive paste, the conductive paste is fired in a firing furnace. The sintering temperature is kept at 850 ℃ for 10 minutes, and the total sintering time is 60 minutes.
[ measurement of sheet resistance ]
First, the sheet resistance R of a square pad pattern formed on an alumina substrate as a test piece was measured 0 . Sheet resistance R 0 The measurement was performed by the 4-terminal method using a testing machine. Next, a high-sulfur environment was performed following ASTM B809-95(60 ℃, 1000 hours)The following vulcanization resistance test. That is, 200g of a 0.5 wt% potassium nitrate aqueous solution was placed between the bottom of the dryer, 50g of sulfur powder and a test piece were placed on the well plate, the lid of the dryer was closed, and the electrode was stored at 60 ℃ for 1000 hours to conduct an accelerated test of the vulcanization of the electrode. After the storage, the sheet resistance R1 was measured. In order to evaluate the deterioration of the electrode due to vulcanization, the rate of change in sheet resistance before and after storage was calculated by the following formula. Tables 1 and 2 show the sheet resistance change rates of the examples and comparative examples.
Rate of change of sheet resistance ═ R 1 -R 0 )/R 0
[ photographing with SEM ]
Fig. 2 shows an SEM photograph taken with a Scanning Electron Microscope (SEM) at a magnification of 1500 times of a cross section of a test piece produced under the same conditions as in example 4 in which the rate of change in sheet resistance is relatively small. Fig. 3 shows an SEM photograph of a cross section of a test piece produced under the same conditions as in comparative example 3 (which is an insulating material) in which the sheet resistance change rate is large, taken by SEM at a magnification of 1500 times. The test piece was stored in a sulfur atmosphere (60 ℃ C.) for 1000 hours and then observed by SEM.
As is clear from the results shown in tables 1 and 2, the rate of change in sheet resistance of the electrode patterns obtained by firing the conductive pastes of examples 1 to 10 was 11% or less, and was relatively low. In contrast, the electrode patterns obtained by firing the conductive pastes of comparative examples 1 to 4 had a sheet resistance change rate of 95% or more, or the sheet resistance after storage in the accelerated vulcanization test was too high to be measured.
In the SEM photograph of the example shown in fig. 2, the portion where silver sulfide 20 is formed by vulcanization is a portion where the film thickness d of the surface of the sintered body 10 (silver particle) of the conductive paste is about 50 nm. In the example shown in fig. 2, a film of silver sulfide is deposited on the electrode surface, but sulfur does not penetrate into the electrode. Therefore, no cracks or the like were observed in the electrode. That is, in the example shown in fig. 2, it is clear that the fired body 10 is hardly affected by the formation of the silver sulfide 20.
On the other hand, in the SEM photograph of the comparative example shown in fig. 3, the silver sulfide 20 was formed in the sintered body 10 (silver particles) of the conductive paste at the portion where the silver sulfide 20 was formed by the vulcanization until the film thickness d became about 250 nm. That is, as compared with the example shown in fig. 2, it can be understood that in the case of the comparative example shown in fig. 3, the silver sulfide thin film is thick and is sulfided into the electrode. Therefore, as is clear from the SEM photograph of fig. 3, in the case of the test piece of fig. 3, the crack 30 is generated inside the fired body 10 (electrode). That is, in the comparative example, the reason why the sheet resistance was greatly increased was considered to be the occurrence of cracks due to the influence of vulcanization.
[ Table 1]
[ Table 2]
Description of the reference numerals
10 sintered body of conductive paste
20 silver sulfide
30 cracks
100 chip resistor
102 alumina substrate
104 resistor body
106 extraction electrode
108 lower surface electrode
110 connecting electrode
112 nickel plating film
114 tin plating film
Film thickness of silver sulfide
Claims (7)
1. A conductive paste, comprising:
(A) alloy particles containing Ag and Sn;
(B) a glass frit; and
(C) a thermoplastic resin, and a thermoplastic resin,
(A) the weight ratio of Sn in the alloy particles is less than 10 wt%.
2. The conductive paste according to claim 1,
(A) the weight ratio of Ag in the alloy particles is 50 wt% or more.
3. The conductive paste according to claim 1 or 2,
the content of the glass frit (B) is 1 to 20 parts by weight relative to 100 parts by weight of the alloy particles (A).
4. The conductive paste according to any one of claims 1 to 3,
the conductive paste further comprises: (D) a silica filler.
5. The conductive paste according to claim 4,
the (B) glass frit comprises SiO 2 And TiO 2 2 ，
SiO contained in the glass frit (B) 2 Of (B) and SiO contained in the silica filler (D) 2 The weight ratio of (A) to (B) is 1: 0.25 to 1: 9.8.
6. An electrode obtained by firing the conductive paste according to any one of claims 1 to 5.
7. A chip resistor having the electrode according to claim 6.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2020-005224 | 2020-01-16 | ||
| JP2020005224 | 2020-01-16 | ||
| PCT/JP2021/000345 WO2021145269A1 (en) | 2020-01-16 | 2021-01-07 | Electroconductive paste, electrode and chip resistor |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN114930467A true CN114930467A (en) | 2022-08-19 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202180009442.0A Pending CN114930467A (en) | 2020-01-16 | 2021-01-07 | Conductive paste, electrode, and chip resistor |
Country Status (5)
| Country | Link |
|---|---|
| JP (1) | JPWO2021145269A1 (en) |
| KR (1) | KR20220123286A (en) |
| CN (1) | CN114930467A (en) |
| TW (1) | TW202146592A (en) |
| WO (1) | WO2021145269A1 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2024042764A1 (en) * | 2022-08-26 | 2024-02-29 | ナミックス株式会社 | Conductive paste, electrode, electronic component, and electronic device |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5346651A (en) | 1993-08-31 | 1994-09-13 | Cerdec Corporation | Silver containing conductive coatings |
| JP2003115216A (en) * | 2001-07-19 | 2003-04-18 | Toray Ind Inc | Conductive paste |
| US20100096014A1 (en) * | 2006-12-25 | 2010-04-22 | Hideyo Iida | Conductive paste for solar cell |
| TWI552975B (en) * | 2011-10-25 | 2016-10-11 | 賀利氏貴金屬北美康舍霍肯有限責任公司 | Electroconductive paste composition containing metal nanoparticles |
| US9899545B2 (en) | 2013-03-27 | 2018-02-20 | Cheil Industries, Inc. | Composition for forming solar cell electrode and electrode produced from same |
| JP7132591B2 (en) * | 2018-03-28 | 2022-09-07 | ナミックス株式会社 | Conductive paste and sintered body |
-
2021
- 2021-01-07 WO PCT/JP2021/000345 patent/WO2021145269A1/en active Application Filing
- 2021-01-07 CN CN202180009442.0A patent/CN114930467A/en active Pending
- 2021-01-07 JP JP2021571163A patent/JPWO2021145269A1/ja active Pending
- 2021-01-07 KR KR1020227026685A patent/KR20220123286A/en unknown
- 2021-01-12 TW TW110101115A patent/TW202146592A/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| WO2021145269A1 (en) | 2021-07-22 |
| KR20220123286A (en) | 2022-09-06 |
| JPWO2021145269A1 (en) | 2021-07-22 |
| TW202146592A (en) | 2021-12-16 |
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