TW201108255A - Conductive composition for forming electrode - Google Patents

Abstract

The present invention relates to a composition for forming conductive electrodes. The composition for forming conductive electrodes according to the present invention has superior adhesion strength of the bond between the coating and a substrate, obtains excellent electrical resistivity characteristics in a low-temperature region of 300 DEG C or lower, exhibits remarkably superior weldability to a solder ribbon when applied to solar cells, has excellent printing characteristics to achieve an electrode pattern with a high resolution, and has excellent rheological properties to obtain a high aspect ratio.

Description

201108255 VI. Description of the invention: c invention belongs to the present invention. The invention relates to a composition for forming an electroconductive electrode, and more particularly to a coating adhesion strength to a substrate. High, even in the low temperature region below 300C, excellent specific resistance characteristics can be obtained, and when applied to a solar cell, the electrode pattern is excellent in the weldability with the solder ribbon, and the printing characteristics are excellent, and the electrode pattern of the resolution can be realized. A composition for forming a conductive electrode having an aspect ratio (ASpect rati〇) can be obtained because of excellent rheological properties. BACKGROUND OF THE INVENTION BACKGROUND OF THE INVENTION Various electronic components, such as solar cells, display elements, and RFID devices, are used in low-temperature electrode technology, which utilizes mixed conductive powders, thermosetting resins (epoxy, materials). ), a hardener, a solvent, etc. to make a paste. However, such a conductive paste is hardened when heated, and is chemically bonded to the substrate by a bio-compound, and is difficult to be obtained because the adhesion between the conductive powders is low. The disadvantage of excellent conductivity 14. As an example, in the case of a solar cell, the polarity of the electrode and the ribbon is required, and the epoxy resin is thermally deformed due to the applied temperature (150 to 450 C), which causes solder fusion. Reduced problems. In the present invention, it is an object of the present invention to provide a conductive electrode-forming composition which has high adhesion to a coating film of a substrate, and can be used in a low temperature region of 300 ° C or lower. Excellent specific resistance characteristics are obtained. When applied to a solar cell, it is excellent in weldability to a solder ribbon, and has excellent printing characteristics, so that a high-resolution electrode pattern can be realized, and a high aspect ratio can be realized because of excellent rheological properties ( Aspect ratio). Means for Solving the Problems In order to achieve the above object, the present invention provides a conductive electrode-forming composition comprising: a conductive powder; a water glass; a binder; and a solvent. Conveniently, the foregoing invention comprises: 30 to 95% by weight of the conductive powder; 0.1 to 20% by weight of the water glass; 0.5 to 50% by weight of the binder; and the balance of the solvent. Moreover, the present invention provides an electrode or a wiring forming method using the conductive electrode forming composition, an electrode for an electronic material and an electrode wiring formed by the above method, and a solar cell, a display device, and an RHD device including the electrode or the electric wiring. . EFFECT OF THE INVENTION 201108255 According to the present invention, it is possible to provide a conductive paste composition which has a high degree of coating with a substrate, even if it is. Excellent low-resistance characteristics can be obtained in the low-temperature region below c. When used in solar cells, it is excellent in solderability to the solder ribbon, and excellent in printing characteristics, and high-resolution electrode pattern can be realized. It is possible to see a high aspect ratio (Aspect ratio) 〇I: Implementing a cold type 3 to implement the invention. The composition for forming a conductive electrode of Benomin is characterized by comprising a conductive metal powder, water glass, and a binder. And solvent. In the present invention, the "electrode-forming composition" includes a composition used as a material for forming a circuit (such as an electronic device composed of a laminated structure or a wiring board composed of a single layer or a plurality of layers). Therefore, it is not only used for electrodes for solar cells, display elements, RFID elements, etc., but the electric wiring used for such devices is also here. The conductive electrode-forming composition of the present invention can be prepared into a paste or an ink. The properties of the composition are obtained by adjusting the type of the conductive powder used and the weight ratio of the organic substance (binder, solvent). The conductive powder in the composition for forming a conductive electrode of the present invention may be a metal, an alloy or a metal oxide powder. At this time, the metal may be silver, gold, I bar, indium, copper, nickel, iron, zinc, wrong, tin, or the like. A silver powder having a lower specific resistance or a metal powder coated with silver may be suitably exemplified, and the metal powder coated with silver may, for example, be a nickel powder, a copper powder, a tin powder or an alloy powder thereof. 201108255 The shape may be spherical, plate-shaped, needle-shaped, indefinite shape, etc., and the average particle diameter of the particles is preferably 0.01 to 30 μm. When the average particle diameter is smaller than Ο.ΟΙμιη, the powders agglomerate with each other and are difficult to be highly dispersed, and it is difficult to be gelatinized due to high viscosity. When the thickness exceeds 30 μm, there is a problem that it is difficult to form a fine pattern when the conductor pattern is formed. The conductive powder preferably contains 30 to 95% by weight in the solid content, and when the addition is less than 30% by weight, the contact density of the conductive powder is small, the pattern height is low when the fine pattern is realized, and the line resistance characteristics are not obtained. Full, the viscosity of the paste is low, and sometimes it will lead to the extension of the pattern. On the other hand, when it exceeds 95% by weight, the conductive powder is difficult to be uniformly dispersed, and the coatability is also lowered to form a conductor having a non-uniform pattern. The water glass used as the inorganic binder contains a substance represented by the following chemical formula. M20-nSi02-H20 (M is an alkali metal, and η is a number from 1 to 8). The water glass is an alkali metal salt obtained by melting cerium oxide and a base, or an aqueous solution thereof, as a specific example, Examples are Si02. Κ20, Si02. Li20, SiO2, Na20, and the like. The content of the water glass is not particularly limited as long as it can achieve the object of the invention, and is preferably from 0.1 to 20% by weight, based on the weight of the conductive paste, of from 1.0 to 10% by weight. When the content of the water glass is less than 0.1% by weight, the strength is insufficient. If the content of the water glass exceeds 20% by weight, it is difficult to expect excellent electrical characteristics. The binder used in the composition for forming a conductive electrode of the present invention can be used in a known field. For example, a cellulose 201108255-dimensional resin such as fluorenyl cellulose, ethyl cellulose, nitrocellulose, hydroxy cellulose or hydroxypropyl cellulose; decyl methacrylate, n-butyl methacrylate, hydrazine; An acrylic resin such as ethyl acrylate or isobutyl methacrylate; or a copolymer thereof, an alkyd resin, a saturated polyester resin, a butyral resin, or polyvinyl alcohol. The binder may be used alone or in combination of two or more. The content of the binder is from 0.5 to 50% by weight, based on the weight of the conductive composition, preferably from 1 to 30% by weight. The solvent which can be used in the present invention is not particularly limited, and the boiling point thereof is preferably 80 ° C or more, more preferably 150 ° C or more. The boiling point described herein is the boiling point at normal pressure. By using a solvent having a boiling point of 80 ° C or higher as a solvent, the drying speed of the composition can be prevented from being too fast. This is advantageous at the point where the formation of the coating film of the composition is prevented from occurring, and at the point of obtaining the electroconductive thin film having the desired characteristics. The upper limit of the boiling point of the solvent is not particularly limited. When considering the drying speed of the coating film, it is preferably 350 ° C or lower, and preferably 300 ° C or lower. A solvent-based aqueous solvent and a non-aqueous solvent can be used. For example, water, a polyhydric alcohol, a polyhydric alcohol alkyl ether, a polyhydric alcohol aryl ether, an ester, a nitrogen-containing heterocyclic compound, a guanamine, an amine, a long-chain alkane, a cyclic alkane, an aromatic hydrocarbon, a monool or the like can be used. These solvents may be used alone or in combination of two or more. As the polyol, ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, diethylene glycol, dipropylene glycol, triethylene glycol or the like can be used. As the polyol alkyl ether, ethylene glycol monoterpene ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, Triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, propylene glycol monobutyl ether, propylene glycol methyl ether, dipropylene glycol decyl ether and the like. As the polyol aryl ether, ethylene glycol monophenyl ether or the like can be used. 201108255 Acetate can use ethyl cellosolve acetate, butyl sulphate acetate, propylene glycol oxime ether acetate, dipropylene glycol oxime ether acetate, γ-butyrolactone, and the like. As the nitrogen-containing heterocyclic compound, fluorenyl-indenyl quinone, 1,3-dimethyl-2-imidazolidinone or the like can be used. The guanamine may be a guanamine, a ruthenium-mercaptoamine, a ruthenium, a ruthenium-dicarbonyl guanamine or the like. As the amine, monoethanolamine, diethanolamine, triethanolamine, tripropylamine, tributylamine or the like can be used. As the long-chain alkane, heptane, octane, decane, decane, eleven, dodecane, tridecane, tetradecane, or the like can be used. As the cyclic alkane, cyclohexane, decalin or the like can be used. As the aromatic hydrocarbon, benzene, toluene, xylene, dodecylbenzene, tridecylbenzene or the like can be used. The monool can use propanol, butanol, pentanol, hexanol, heptanol, octanol, decyl alcohol, cyclohexanol, terpineol, benzyl alcohol, 2-propanol, second butanol, t-butanol , 2-pentanol, 3-pentanol, 2-ethyl-1-butanol, 2-heptanol, 3-heptanol, 2-octanol, 3-octanol, 4-octanol, 2-ethyl Hexanol, decyl alcohol, and the like. Further, the conductive electrode-forming composition of the present invention may further contain an additive which is usually contained, if necessary. Examples of the above-mentioned additives include a tackifier, a stabilizer, a dispersant, a surfactant, a plasticizer, a sentence dyeing agent, a blister agent, and the like, and an electrode forming composition of the present invention. The weight is preferably used in the range of from 1 to 5% by weight. Further, in order to adjust the composition of the conductive electrode forming composition of the present invention, the organic solvent can be further mixed as the viscosity. Examples of the organic solvent include aryl, diterpenoid, symmetrical triterpene benzene, aromatic hydrocarbons such as tetraamine, tetrahydrofuran, and the like; methyl ethyl ketone, methyl isotop, and cyclohexyl The surface of isophorone, etc. Endoamines such as ketone, 丨_methyl_2•scale; ethylene glycol mono(tetra), ethylene glycol monoethyl ether, ethylene glycol monobutyl, diethylene glycol monomethyl ether, diethylene An alcohol monoethyl bond, a diethylene glycol monobutyl group, or an ether lysate corresponding to the propylene glycol derivative; an S-type corresponding to the acetic acid vinegar; malonic acid, succinic acid, etc. The two of the two are the two vinegars, such as vinegar and vinegar. The amount of the organic solvent to be used can be appropriately selected depending on the type and content of the conductive particles to be used, and the printing or coating method of the conductive composition. When the conductive electrode-forming composition of the present invention is prepared into a paste form, the necessary components and optional components described above are mixed at a ratio of finger ,, and then uniformly dispersed by a kneader such as a stirrer or a triaxial roll. To make things. Suitably, the conductive paste of the present invention utilizes a Brookfield HBT viscometer to have a #51 rotor at a temperature of 25. . The lower shear rate (10) can be measured with a viscosity of 1 to 3 〇〇 1 ^ s when measured under conditions of 3.84 sec. When the conductive electrode-forming composition of the present invention is prepared into an ink form, the conductive ink of the present invention can be reduced in a wide range. Specifically, the viscosity of the conductive ink of the present invention is 2 (1 〇〇 mPa S or less in TC, particularly preferably 50 mPa·s or less. The viscosity of the ink is appropriately mixed, and the aforementioned components of the towel are 9 The mixing amount can be determined. In this case, the viscosity can be measured by a vibrating viscometer (Mountain-Electric Products VM-100A) or a viscoelastic setting device (Haake) RS082). When the conductive ink of the present invention is applied to an inkjet printing method as described later, the viscosity (20 C) is preferably set to 50 mPa·s or less, particularly 30 mPa·s or less. The conductive ink composition of the present invention is utilized. For example, it is prepared by the method described below. The conductive metal powder is dispersed in a solvent to obtain a slurry. Water glass of an inorganic binder is added to the slurry thus obtained, and stirred and mixed. The desired ink is obtained by this treatment. When the conductive electrode-forming composition obtained by the present invention is prepared into a paste, a method of using a wire mesh formed by sputtering, spraying, sintering, or the like to form the mixed component may be used. Printing, transfer, dip coating, etc. can be printed or coated in an optional manner, and can be used at 15 〇 to 2 〇〇. (: heating for 10 to 30 minutes to harden, thereby forming various electronic parts (solar cells) Electrodes used in displays, RFID devices, etc.).

The present invention provides a method for forming an electrode of a solar cell and a solar cell electrode produced by the above method. The method is characterized in that the conductive paste is printed on a substrate, dried, hardened or fired, and the sun of the present invention. In the method for forming a battery electrode, in addition to the use of the conductive paste obtained according to the present invention, the substrate, printing, drying, hardening or firing can of course be applied to a method used for the manufacture of a conventional solar cell. In one example, the substrate may be a Si substrate, the electrode may be a front surface electrode of the solar cell, and the printing may be screen printing, and the drying may be performed at 60 to 150 ° C for 3 to 30 minutes. And hardening or firing can be done at 15〇3〇〇. 〇 5 to 6 minutes. Further, drying and baking can be carried out at the same time, and it is carried out at a low temperature of 1 to 30 (TC 10 201108255 for 5 to 60 minutes. The printing is preferably printed to a thickness of 15 to 50 μm. As a specific example, in the Japanese Patent Laid-Open Publication No. In the structure of the solar cell described in the above-mentioned Japanese Patent Application No. 2005-268239, the electrode for forming an electrode of the solar cell of the present invention can form an electrode of a solar cell. The paste composition for forming a conductive electrode of the present invention is suitably used in An electronic device composed of a laminated structure, or a circuit forming material such as a wiring board composed of a single layer or a plurality of layers. It is particularly suitable for a solar cell, a display element, and an RFID element. Specifically, the present invention is applied by a known printing method. The paste is printed on a substrate composed of a plurality of materials such as glass, ceramics, metal, plastic, etc., and is printed in a predetermined printing pattern. Thereafter, the formed printing pattern is fired under the atmosphere, in an inert gas atmosphere or under vacuum, and a desired pattern is formed. The obtained conductive film. The adhesion strength of the coating film of the electrode and the substrate obtained from the conductive paste obtained according to the present invention. High, even in the low temperature region below 300 ° C, excellent specific resistance characteristics can be obtained, and the welding property with the solder ribbon is excellent when applied to a solar cell, and the printing characteristics are excellent, and a high-resolution electrode pattern can be realized. The rheological properties of the paste are excellent, and a high aspect ratio can be achieved. Hereinafter, suitable embodiments will be proposed for the understanding of the present invention, but the following examples are merely illustrative of the scope of the present invention. The present invention is not limited to the following examples. EXAMPLES Example 1 A spherical silver 11 having an average particle diameter of Ο. ίμιη was mixed and mixed by a three-roll kneader. 201108255 Powder 35 wt%, potassium citrate 1 wt%, binder was hydroxyl group 11% by weight of cellulose, 12% by weight of isobutyl methacrylate, 30% by weight of ethylene glycol, 10% by weight of Dingsay, and 1% by weight of dispersant to prepare a conductive paste. Except that in the foregoing Example 1, 70% by weight of spherical silver powder having an average particle diameter of 2 · 5 μm, 3% by weight of potassium citrate, 3 % by weight of hydroxycellulose, and isobutyl methacrylate 3 were used. A conductive paste was prepared in the same manner as in Example 1 except that the solvent was ethylene glycol 15% by weight, dingsasu 5% by weight, and dispersant 1% by weight. Example 3 Except in the foregoing examples 1 used 82% by weight of spherical silver powder having an average particle diameter of 2.5 μm, 3% by weight of potassium citrate, 2% by weight of hydroxycellulose, 0.5% by weight of isobutyl methacrylate, and the solvent is ethylene glycol. A conductive paste was prepared in the same manner as in Example 1 except that 8% by weight, Dingsailu 4% by weight, and 0.5% by weight of a dispersing agent. Example 4 In addition to the above Example 3, water glass was used. A conductive paste was prepared in the same manner as in Example 1 except that the amount of sodium 3% was 3% by weight. Example 5 The same procedure as in Example 1 was carried out except that in the above Example 3, water glass was used in an amount of 3% by weight of lithium niobate. The method is made into a conductive paste. (Example 6) Conductivity 12 201108255 was prepared in the same manner as in Example 1 except that the conductive powder was 82% by weight of the silver-coated copper powder in the foregoing Example 3. Comparative Example 1 Except that 70% by weight of the spherical silver powder having an average particle diameter of 2.5 μm was used in the foregoing Example 1, the epoxy resin was 10% by weight of the bisphenol fluorene-based resin, 1% by weight of the amine-based hardener, and the solvent was B2. A conductive paste was prepared in the same manner as in Example 1 except that 13% by weight of the alcohol, 5% by weight of Dingsailu, and 1% by weight of the dispersant. Comparative Example 2 Except that 85% by weight of the spherical silver powder having an average particle diameter of 2 to 5 μm was used in the above-mentioned Example 1, the epoxy resin was 5% by weight of the bisphenol fluorene-based resin, 0.5% by weight of the amine-based curing agent, and the solvent was ethylene. A conductive paste was prepared in the same manner as in Example 1 except that 5% by weight of the alcohol, 4% by weight of Dingsailu, and 0.5% by weight of the dispersant. Experimental Examples The results of measuring the specific resistance, the coating film strength, the substrate adhesion, the welding strength, the resolution, and the aspect ratio of the conductive pastes prepared in Examples 1 to 6 and Comparative Examples 1 to 2 are as follows. 1 is shown. After the electrode paste was printed on an alumina substrate by a specific resistance, it was baked at 25 ° C for 30 minutes, and then the surface resistance was measured with a 4-point probe, and the height was measured by a scanning electron microscope (SEM). The film strength was measured by using a pencil-core scribe line of 4B to 4H on the test piece which was fired. The adhesion evaluation of the substrate was carried out to evaluate the adhesion of the lattice (ASTNI D3359), and the adhesion of 100 lattices was evaluated by 3M tape #610, and the number of lattices dropped was recorded. The welding strength of the d-series was simultaneously bonded after the electrode and the ribbon were fired. The force measuring device (Xijin 13 201108255 Trading Co., Ltd. SS30WD) measures the shedding strength. The resolution evaluation was performed by masking, drying, and baking with a resolution of a line width of 60 to 120 μm, and recording the resolution as a case where the line width change rate of the pattern was within 10%. The aspect ratio is expressed in terms of the height of the pattern/line width x100. 14 201108255 Comparative Example 2 00 in d 1 1 inch 〇 21.4 PQ X 10 learning CO 50 90gf S 17.4 Comparative Example 1 〇ο 1 1 cn 88.1 Κ CS Learning » Η 10 130gf g 11.2 Example 6 oo CO (N 〇co inch d 12.8 X inch 〇 〇 〇 m 〇 314gf o 24.4 Example 5 00 CO α d 00 inch l〇d 11.2 X (Ν single (N learning 1-^ 143gf g 28.51 Example 4 oo CN d Oo inch 〇CN W inch inch 〇学〇 272gf o 29.01 Example 3 CN 00 1 md 00 inch to 〇OO ^6 X inch m 〇学〇m 〇286gf o 27.7 Example 2 〇1 C^l cn m 10.2 X inch 〇m abusive 〇 313gf § 21.23 Example 1 in CO ) 1—Η CT CT CTN X 寸 〇 〇 〇 〇 〇 〇 〇 〇 〇 〇 〇 〇 〇 〇 〇 〇 〇 〇 〇 〇 〇 〇 〇 〇 〇 〇 〇 〇 〇 〇 〇 〇 〇 〇 〇 〇 〇 〇 〇 〇 〇 〇 〇 〇 〇 〇 Sodium citrate citrate bisphenol oxime resin (wt%) Amine (wt%) Hydroxycellulose (Wt%) Isobutyl methacrylate (wt%) Ethylene glycol (wt%) Ding Salu (wt%) Disperse enthalpy (Wt%) 250 degree-30 minutes hardened pencil-core hardness determination of alumina substrate yttrium nitride substrate glass substrate adhesion strength determination After printing, the line width variation rate is less than 10%, the round case height/line width ratio is conductive powder 1 CN water glass] Water glass 2 Water glass 3 Epoxy hardening 剤Binder 1 Binder 2 Solvent 1*1 剤*2 Add剤 specific resistance (*10_6Ωα·η) Coating strength Substrate adhesion: Adhesive tape adhesion (number of detachment units) Welding strength (gf) Resolution (μπη) Aspect ratio (%) ±i 15 201108255 It can be confirmed from Table 1 above. The substrate has excellent adhesion, and the substrate material is excellent in adhesion strength to metals, ceramics, and glass, and can be widely applied to solar cells, displays including PDPs, and electronic components such as RFID. In addition, conductivity obtained by the present invention The paste has excellent specific resistance characteristics even in a low temperature region (below 300 ° C), and can be applied to a low temperature step such as a heterojunction solar cell (HITCell), a thin film solar cell, or a polymer solar cell in the field of solar cells. The field of electrodes for low temperature. Further, the conductive paste obtained by the present invention has a high adhesion strength of 200 gf or more after welding the welding tape, is excellent in welding strength, and is excellent in rheological properties of the paste, and is easy to realize a high-resolution pattern of 80 μm or less. . Further, the conductive paste obtained by the present invention has a high aspect ratio as compared with the already existing paste, and is excellent in mesh permeability at the time of printing, and can realize a high aspect ratio pattern, so that the high resolution is high. Excellent line resistance characteristics are also obtained. Simple description of C pattern 3 (none) [Explanation of main component symbols] (none) 16

Claims (1)

201108255 VII. Patent application scope: 1. A composition for forming a conductive electrode, comprising: a conductive powder; a water-breaking glass, a binder; and a solvent. 2. The conductive electrode-forming composition according to claim 1, comprising: 30 to 95% by weight of the conductive powder; 0.1 to 20% by weight of the water glass; 0.5 to 50% by weight of the binder; and Solvent. 3. The composition for forming a conductive electrode according to the first aspect of the invention, wherein the water glass is one or more selected from the group consisting of potassium citrate, sodium citrate and lithium niobate. 4. The conductive electrode-forming composition of claim 1, wherein the water glass is selected from the group consisting of the following chemical formula: M20-nSi02-H20 (M is an alkali metal, and η is 1 to 8) Number). 5. The conductive electrode-forming composition according to the first aspect of the invention, wherein the conductive powder is selected from the group consisting of silver powder, gold powder, platinum powder, palladium powder, indium powder, copper powder, nickel powder, iron One or more powders of the group consisting of a powder, a zinc powder, a lead powder, a tin powder, a tantalum powder, a nickel powder coated with silver, a copper powder coated with silver, and a tin powder coated with silver. The composition for forming a conductive electrode according to the first aspect of the invention, wherein the binder is a cellulose resin, an acrylic resin or the like, an alkyd resin, or a saturated polyester resin. , butyraldehyde resin or polyvinyl alcohol. 7. The conductive electrode-forming composition according to claim 1, wherein the solvent has a boiling point of 80 to 350 °C. 8. An ink composition comprising a conductive electrode-forming composition selected according to any one of claims 1 to 7. A method of forming an electrode for an electronic material, characterized in that a composition selected from any one of items 1 to 8 of the patent application is printed on a substrate, followed by drying and firing. 10. An electrode for an electronic material obtained by the method of claim 9 of the patent application. A solar cell comprising an electrode for an electronic material according to claim 10 of the patent application. 12. A display element comprising an electrode for an electronic material as in claim 10 of the patent application. 13. An RFID component comprising an electrode for an electronic material as in claim 10 of the patent application. 18 201108255 IV. Designated representative map: (1) The representative representative of the case is: ( ). (None) (2) A brief description of the symbol of the representative figure: 5. If there is a chemical formula in this case, please disclose the chemical formula that best shows the characteristics of the invention: