JP2015187977A - Conductive laminate and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a conductive laminate capable of improving thermal shock resistance even when a conductive film is formed on a glass substrate.SOLUTION: The method for manufacturing a conductive laminate comprises: applying and sintering a conductive layer precursor including metal particles, a glass frit, an organic binder, and a dispersion medium on a glass substrate; and forming a plated layer on the obtained conductive layer. The conductive layer has a phase separation structure including metal and low melting point glass and including a continuous phase formed by the metal. The phase separation structure of the conductive layer is a co-continuous structure or a sea island structure, and the plated layer may be laminated on the continuous phase formed by the metal out of the surface of the conductive layer. In the conductive layer, a mass ratio of the metal to the glass frit may be the former/the latter=93/7-50/50. The glass frit may be bismuth based glass frit; the metal of the conductive layer may be silver; the plated layer may include nickel; and the average thickness of the plated layer may be a 0.3-2 μm level.

Description

  The present invention relates to a conductive laminated body used in the field of electronics and having a conductive film formed on a glass substrate, and a method for manufacturing the same.

  Conductive pastes are widely used in the electronics field because various patterns such as electrodes can be easily formed by printing or the like. Recently, a method of further reducing resistance by heating and sintering a pattern formed by coating has been adopted. In this method, the metal powder used for the conductive paste has a lower contact resistance between the metal powders due to the progress of sintering, and can exhibit better conductivity as a coating pattern.

  As such a method, a conductive paste (a conductive paste containing a metal powder, a glass powder, and an organic vehicle) as disclosed in Japanese Patent Laid-Open No. 2003-132735 (Patent Document 1) is widely used. In addition, it is used for forming an internal or external electrode of an LED package using a ceramic substrate such as alumina or aluminum nitride, wiring formation, or the like. Further, although Patent Document 1 does not describe plating, the electrode is plated with Ni / Au or Ni / Pd / Au to improve long-term reliability against a decrease in adhesion strength or discoloration. Often used.

  In addition, a method of forming a conductive film using a conductive paste on a glass substrate such as silicate glass or borosilicate glass instead of a ceramic substrate has been proposed for the purpose of reducing product costs.

  JP 2013-182714 A (Patent Document 2) includes metal nanoparticles and a softening point on a substrate via an adhesive layer containing a metal particle and a bismuth glass frit having a softening point of 500 ° C. or less. A conductive laminate having a conductive coating layer formed on a substrate by firing a laminate in which a coating layer substantially free of bismuth-based glass frit having a temperature of 500 ° C. or less is formed. A method of manufacturing is disclosed. This document describes that a plating layer is further formed on the conductive coating layer.

  However, since the conductive laminate using a glass substrate as a substrate has a low strength and a brittle nature compared to a ceramic substrate such as alumina, when a conductive film (sintered metal film) is formed on the glass substrate, The thermal stress generated by the difference in coefficient of linear expansion between the metal film and the glass substrate was likely to cause cracks in the glass portion directly under the metal film, and the thermal shock resistance (heat resistance) was extremely weak. Furthermore, in the laminated body increased in thickness by plating, cracks occurred in the glass even when the thermal shock was about reflow, and practical use was difficult.

JP 2003-132735 A (Claim 1, paragraph [0002]) JP 2013-182714 A (Claims)

  Therefore, the objective of this invention is providing the electroconductive laminated body which can improve a thermal shock resistance (heat resistance), and its manufacturing method, even if it forms a electrically conductive film on a glass substrate.

  Another object of the present invention is to provide a conductive laminate that can improve the adhesion between a glass substrate and a conductive film, and a method for producing the same.

  Still another object of the present invention is to provide a conductive laminate that can improve durability such as solderability and discoloration resistance, and a method for producing the same.

  As a result of intensive studies to achieve the above-mentioned problems, the present inventors have found that a conductive layer having a phase separation structure including a metal and a low-melting glass on a glass substrate and including a continuous phase formed of the metal. The inventors have found that the thermal shock resistance can be improved even when a conductive film is formed on a glass substrate by laminating and further depositing a plating layer on the conductive layer, and the present invention has been completed.

  That is, the conductive laminate of the present invention is a conductive laminate including a glass substrate, a conductive layer laminated on the glass substrate, and a plating layer laminated on the conductive layer, The conductive layer includes a metal and a low-melting glass, and has a phase separation structure including a continuous phase formed of the metal. The phase separation structure of the conductive layer may be a co-continuous structure or a sea-island structure, and the plating layer may be laminated on a continuous phase formed of metal in the surface of the conductive layer. The porosity of the plating layer may be about 40 to 90%. In the conductive layer, the volume ratio between the metal and the low-melting glass may be the former / the latter = 93/7 to 50/50. The softening point of the low melting point glass may be a temperature lower than the firing temperature of the conductive layer. The low-melting glass may be a fired product of bismuth-based glass frit. The metal of the conductive layer may be silver. The plating layer may contain nickel. The average thickness of the plating layer may be about 0.3 to 2 μm.

  The present invention includes a conductive layer forming step of forming a conductive layer by applying a conductive layer precursor containing metal particles and glass frit on a glass substrate, and then baking the plated conductive layer. The manufacturing method of the said conductive laminated body including the plating layer formation process which forms is also included. The conductive layer precursor may further contain an organic binder.

  In the present invention, a conductive layer having a phase separation structure including a metal and a low melting point glass and including a continuous phase formed of the metal is laminated on a glass substrate, and a plating layer is further formed on the conductive layer. Since they are laminated, the thermal shock resistance can be improved even when a conductive film is formed on a glass substrate. Moreover, since a conductive layer contains low melting glass, the adhesiveness of a glass substrate and a conductive film can also be improved. Furthermore, when the plating layer is formed of a plating film containing nickel, durability such as solderability and discoloration resistance can be improved.

FIG. 1 is a scanning electron microscope (SEM) photograph of the surface of the conductive layer of the conductive laminate obtained in Example 1. FIG. 2 is an SEM photograph of the surface of the plating layer of the conductive laminate obtained in Example 1. FIG. 3 is an SEM photograph of the surface of the conductive layer of the conductive laminate obtained in Comparative Example 1. FIG. 4 is an SEM photograph of the surface of the plating layer of the conductive laminate obtained in Comparative Example 1.

[Conductive laminate]
The conductive laminate of the present invention includes a glass substrate, a conductive layer laminated on the glass substrate, and a plating layer laminated on the conductive layer.

(Glass substrate)
As the glass substrate, conventional silicate glass (silicate glass), for example, soda glass, borosilicate glass, crown glass, barium-containing glass, strontium-containing glass, boron-containing glass, low alkali glass, alkali-free glass, crystal Substrates formed of transparent glass, silica glass, quartz glass, heat-resistant glass, etc. can be used. Among these glass substrates, alkali glass substrates such as soda glass and low alkali glass, and borosilicate glass substrates are widely used.

  The surface of the glass substrate is subjected to oxidation treatment [surface oxidation treatment, for example, discharge treatment (corona discharge treatment, glow discharge, etc.), acid treatment (chromic acid treatment, etc.), ultraviolet irradiation treatment, wrinkle treatment, etc., surface unevenness treatment (solvent Surface treatment such as treatment, sandblast treatment, etc.).

  What is necessary is just to select the thickness (average thickness) of a glass substrate suitably according to a use, for example, 0.001-10 mm, Preferably it is 0.01-5 mm, More preferably, it is 0.05-3 mm (especially 0.1-3 mm). 1 mm) or so.

(Conductive layer)
The conductive layer includes a metal and glass component and has a phase separation structure including a continuous phase formed of the metal. In the present invention, since the conductive layer has such a phase separation structure, a phase formed of a low-melting glass or a void (on a continuous phase (metal phase) formed of metal on the surface of the conductive layer ( (Non-metallic phase) exists as a disperse phase and / or a continuous phase. Therefore, a mesh-like plated layer can be easily formed on the continuous phase formed of metal. However, the plated layer having such a structure has a cushioning property (resistance to resistance) compared to a conventional plated layer coated on the entire surface. It is a plating layer with excellent impact properties. This is because the thermal stress generated due to the difference in coefficient of linear expansion from the glass substrate can be relaxed (absorbed) by the voids in the plated layer.

  The phase separation structure including the metal phase includes a bicontinuous structure and a sea-island structure. The non-metallic phase is a phase containing a low-melting glass. Usually, in addition to a phase (glass phase) formed of low-melting glass, a void portion (void phase) due to shrinkage due to sintering of a frit raw material or disappearance of a binder or the like. )including.

  In the phase separation structure on the surface of the conductive layer (the entire surface of the conductive layer), the area ratio occupied by the metal phase is, for example, 40 to 90%, preferably 50 to 80%, and more preferably about 55 to 75%. If the area ratio of the metal phase is too small, it is difficult to form a continuous phase with the metal, and the conductivity of the conductive laminate may be reduced. On the other hand, if it is too large, it becomes difficult to form a mesh-like plating layer, and since the plating layer is formed on almost the entire surface of the conductive layer, it becomes difficult to relieve stress, and the thermal shock resistance of the conductive laminate is reduced. May decrease.

  Examples of the metal (metal atom) include transition metals (for example, periodic table Group 4A metals such as titanium and zirconium; periodic table Group 5A metals such as vanadium and niobium; periodic table Group 6A metals such as molybdenum and tungsten). Periodic Table Group 7A metals such as manganese; Periodic Table Group 8 metals such as iron, nickel, cobalt, ruthenium, rhodium, palladium, rhenium, iridium and platinum; Periodic Table Group 1B metals such as copper, silver and gold Etc.), Periodic Table Group 2B metals (eg, zinc, cadmium, etc.), Periodic Table Group 3B metals (eg, aluminum, gallium, indium, etc.), Periodic Table Group 4B metals (eg, germanium, tin, lead, etc.) ), Periodic table Group 5B metals (for example, antimony, bismuth, and the like). These metals can be used alone or in combination of two or more, and may be an alloy. Among these metals, from the viewpoint of conductivity, Group 8 metal of the periodic table (iron, nickel, rhodium, palladium, platinum, etc.), Group 1B metal of the periodic table (copper, silver, gold, etc.), periodic table Group 3B metals (such as aluminum) and periodic table Group 4B metals (such as tin) are widely used, and conductive metals, particularly silver, are preferred.

  As the low melting point glass (melting glass), a fired product of a conventional glass frit (melting glass powder or particles) can be used. Examples of conventional glass frit include borosilicate glass frit, zinc borosilicate glass frit, zinc glass frit, bismuth glass frit, and lead glass frit. These glass frit can be used individually or in combination of 2 or more types. Of these glass frits, a bismuth-based glass frit is preferable because it is easily softened, acts as a sintering aid, and can adhere a hard metal to the glass substrate.

The bismuth-based glass frit only needs to contain bismuth oxide (Bi ₂ O ₃ ), and may contain other oxides in addition to bismuth oxide. Examples of other oxides include other metal oxides (for example, alkali metal oxides such as lithium oxide, sodium oxide, and potassium oxide; alkaline earth metal oxides such as magnesium oxide, calcium oxide, strontium oxide, and barium oxide). Periodic Table Group 4A metal oxides such as titanium oxide and zirconium oxide; Periodic Table Group 6A metal oxides such as chromium oxide; Periodic Table Group 8 metal oxides such as iron oxide; Periodic table such as zinc oxide Group 2B metal oxides; periodic table Group 3B metal oxides such as aluminum oxide; periodic table Group 4B metal oxides such as tin oxide and lead oxide), silicon oxide, boron oxide and the like. These other oxides can be used alone or in combination of two or more. Of these other oxides, they often contain lithium oxide, sodium oxide, barium oxide, zinc oxide, lead oxide, silicon oxide, boron oxide, and the like. The ratio of bismuth oxide is, for example, 10% by mass or more, preferably 15% by mass or more (for example, 15 to 95% by mass), more preferably 20 to 90% by mass (particularly 30 to 80% by mass) with respect to the entire glass frit. %) Degree.

  The softening point of the low-melting glass may be, for example, lower than the firing temperature of the conductive film, in other words, the softening point lower than the heat-resistant temperature (softening point) of the glass substrate. Specifically, the softening point of the low-melting glass can be selected from a range of, for example, about 350 to 600 ° C., for example, 380 to 580 ° C., preferably 400 to 580 ° C., more preferably 420 to 580 ° C. It may be about ˜550 ° C.). When the softening point is too high, melt fluidity is lowered, so that it is difficult to form a co-continuous structure or a sea-island structure, and adhesion to the glass substrate is also lowered.

  The volume ratio between the metal and the low-melting glass is, for example, metal / low-melting glass = 93/7 to 50/50, preferably 90/10 to 55/45, and more preferably about 80/20 to 60/40. . When the volume ratio of the metal is too small, it is difficult to form a mesh-like plating layer, and the thermal shock resistance of the conductive laminate may be reduced. Since the metal phase is formed by sintering metal particles, a void of about 7% by volume is generated even without the low melting point glass. However, if the plating layer is formed in this state, the plating solution easily penetrates into the gap, so that the plating film is formed even inside the conductive layer and high stress is generated. Therefore, in order to prevent the plating solution from entering the gap, a predetermined amount of low melting point glass is required with respect to the total amount of metal and low melting point glass. On the other hand, when the volume ratio of the metal is too large, the conductivity of the conductive laminate may be reduced.

  The average thickness of a conductive layer should just be the thickness more than the particle size of the raw material metal particle contained in a conductive layer precursor (coating liquid), for example, 2-20 micrometers, Preferably it is 3-15 micrometers, More preferably, it is 5-10 micrometers. Degree. The thickness of the conductive layer can be measured using a fluorescent X-ray film thickness meter, and the average value is calculated by measuring the thickness of any five points.

(Plating layer)
A plating layer is further laminated on the conductive layer. In the plating layer manufacturing process, plating nuclei are selectively generated and grown on a continuous phase formed of metal in the conductive layer, and no plating film is formed on the surface or voids of the low melting point glass. Therefore, the plating layer has a mesh shape (porous shape) substantially corresponding to the continuous phase.

  The porosity of the plating layer (ratio of the area of the void per unit area), which is the area ratio of the plating layer to the entire surface of the conductive layer, is, for example, 40 to 90%, preferably 50 to 80%, and more preferably. It is about 55 to 75%. If the porosity of the plating layer is too large, the conductivity of the conductive laminate may be reduced. On the other hand, when too small, there exists a possibility that the thermal shock resistance of an electroconductive laminated body may fall.

  The plating type of the plating layer may be formed of metal (particularly conductive metal). As the conductive metal, the metal exemplified in the section of the conductive layer can be used. Among the metals, from the viewpoint of conductivity, Group 8 metal of periodic table (iron, nickel, rhodium, palladium, platinum, etc.), Group 1B metal of periodic table (copper, silver, gold, etc.), Periodic table 3B Group metals (such as aluminum) and Group 4B metals (such as tin) are widely used. From the viewpoint of conductivity, nickel, palladium, and gold are preferable, and durability such as solderability and discoloration resistance is also improved. Nickel is particularly preferable because it can be used.

  These conductive metals can be used alone or in combination of two or more. In particular, a plurality of types of plating films may be combined. For example, a laminated structure of a nickel plating film and another conductive metal film (plating film such as gold or palladium) may be used. It is particularly preferable to laminate a metal plating film formed of another metal after the nickel plating film is laminated. The nickel plating film plays a role as an erosion preventing layer for preventing erosion of the solder to the underlying metal in addition to a function as a bonding layer with the solder at the time of soldering.

  In the present invention, since the metal phase of the conductive layer is selectively plated, it is not necessary to form the plating base layer.

  The average thickness of the plating layer (total thickness in the case of a laminated structure) is, for example, 0.3 to 3 μm (for example, 0.3 to 2 μm), preferably 0.35 to 2 μm, and more preferably about 0.4 to 2 μm. It is. When the plating layer includes a nickel plating film, the average thickness of the nickel plating film is, for example, about 0.2 to 2 μm, preferably about 0.25 to 1.5 μm, and more preferably about 0.3 to 1.5 μm. If the thickness of the plating layer is increased, a plating film may be formed even in the non-metallic phase of the conductive layer, and the plating layer voids may be reduced, eventually resulting in a plating layer having a gap (not a mesh). is there. On the other hand, if the thickness of the plating layer is too small, there is a risk that the function as an erosion preventing layer may be reduced during soldering that is generally used. The thickness of the plating layer can also be measured using a fluorescent X-ray film thickness meter, and the average value is calculated by measuring the thickness of any five points.

[Method for producing conductive laminate]
The conductive laminate is a conductive layer forming step in which a conductive layer precursor containing metal particles and glass frit is applied on a glass substrate and then baked to form a conductive layer. It is manufactured through a plating layer forming step for forming a layer.

  In the conductive layer forming step, first, a conductive paste (coating liquid) containing metal particles and glass frit is prepared as a conductive layer precursor.

  The shape of the metal particles as the metal raw material is not particularly limited, and is a polygonal shape such as a spherical shape (true spherical shape or substantially spherical shape), an elliptical shape (elliptical spherical shape), a polygonal shape (polygonal pyramid shape, a rectangular parallelepiped shape, a rectangular parallelepiped shape, or the like). Etc.), plate-like (flat, scale-like or flake-like), rod-like or rod-like, fiber-like, irregular shape, etc. The shape of the metal particles is usually spherical, ellipsoidal, polygonal, indeterminate.

  The particle size of the metal particles is not particularly limited, but a large amount of non-conductive components (inorganic binder component and resistance adjusting component) are blended. For example, copper particles and nickel particles are used as separate metal particles. In this case, it is advantageous to use metal particles having a small particle size from the viewpoint of uniform dispersibility and alloying during firing. On the other hand, when using alloy particles of copper and nickel, although there is no problem in the uniformity of alloying, it is advantageous to use alloy particles having a small particle size in the same manner from the viewpoint of dispersibility.

  The central primary particle size (D50) of the metal particles can be selected from the range of, for example, about 5 nm to 10 μm, and may be nanometer-sized particles. However, from the viewpoint of handleability and economy, for example, 0.05 It is about 10 to 10 μm, preferably 0.08 to 8 μm, more preferably about 0.1 to 5 μm (particularly 0.2 to 3 μm). If the particle size of the metal particles is too small, the dispersibility in the paste is reduced in addition to the handleability and economy, and if too large, the paste coating property, dispersibility, and uniformity may be lowered.

  Examples of the shape of the glass frit which is a low melting point glass raw material include the shape exemplified in the section of the metal particles, and are usually spherical, ellipsoidal, polygonal, indeterminate.

  The central primary particle size of the glass frit may be, for example, about 0.1 to 10 μm, preferably 0.2 to 8 μm, more preferably about 0.3 to 5 μm (particularly 0.5 to 3 μm). When the particle size of the glass frit is too large, clogging is likely to occur in, for example, screen printing. On the other hand, if the particle size is too small, the dispersibility of the glass frit is lowered, so that the amount of the glass frit used is increased and the conductivity may be lowered.

  The conductive layer paste may further contain an organic binder. Examples of the organic binder include conventional binder resins, such as water-soluble polymer binders (for example, water-soluble acrylic resins, water-soluble urethane resins, water-soluble acrylic urethane resins, water-soluble epoxy resins, water-soluble polyester resins, and celluloses). Derivatives, polyvinyl alcohol, polyalkylene glycol, natural polymer, polyethylene sulfonic acid or its salt, polystyrene sulfonic acid or its salt, formalin condensate of naphthalene sulfonic acid, polyalkyleneimine, polyvinyl pyrrolidone, polyallylamine, polyether polyamine, etc.) , Hot melt resins (for example, polyester resins such as aliphatic or amorphous polyester, polyvinyl acetal resins such as polyvinyl butyral), thermosetting resins (for example, phenol resins, epoxy resins, etc.) Shi resins, such as unsaturated polyester resin) and the like.

  Among these binder resins, water-soluble polymer binders such as cellulose derivatives, for example, cellulose ethers (for example, nitrocellulose; alkylcelluloses such as ethylcellulose; ethylhydroxyethylcellulose, etc.) from the point of acting as a polymer dispersant Alkyl-hydroxyalkyl celluloses; hydroxyalkyl celluloses such as hydroxyethyl cellulose and hydroxypropyl cellulose; carboxyalkyl celluloses such as carboxymethyl cellulose) are preferred, and alkyl celluloses such as ethyl cellulose are particularly preferred.

  The proportion of the organic binder may be, for example, 200 parts by mass or less with respect to 100 parts by mass of the metal particles, for example, 1 to 150 parts by mass, preferably 10 to 100 parts by mass, and more preferably 20 to 80 parts by mass. Part (particularly 30 to 60 parts by mass).

In the conductive paste, a conventional additive, for example, a dispersion medium (saturated or unsaturated C _6-20 aliphatic alcohol such as octanol, aliphatic polyhydric alcohol such as ethylene glycol, fat such as terpineol, etc.) Cyclic alcohols, etc.), colorants (dyeing pigments, etc.), hue improvers, dye fixing agents, gloss imparting agents, metal corrosion inhibitors, stabilizers (antioxidants, UV absorbers, etc.), surfactants or dispersants. (Anionic surfactant, cationic surfactant, nonionic surfactant, amphoteric surfactant, etc.), dispersion stabilizer, thickener or viscosity modifier, humectant, thixotropic agent, leveling agent, An antifoaming agent, a disinfectant, a filler and the like may be included. These additives can be used alone or in combination of two or more.

  The conductive paste is not particularly limited as long as a paste having such a composition can be obtained, but it can be usually prepared by dispersing the metal particles and glass frit using the organic binder.

  As a conductive paste application method (coating method), conventional coating methods such as flow coating method, dispenser coating method, spin coating method, spray coating method, screen printing method, flexographic printing method, casting method, bar coating method, etc. Curtain coating method, roll coating method, gravure coating method, dipping method, slit method, photolithography method, ink jet method and the like can be used. Among the coating methods, a pattern may be formed (drawn) with a coating film, and a sintered pattern (sintered film or sintered body layer) can be formed by firing the formed pattern (drawn pattern). The drawing method (or printing method) for drawing the pattern (coating layer) is not particularly limited as long as it is a pattern forming printing method. For example, a screen printing method, an ink jet printing method, an intaglio printing method (for example, Gravure printing method), offset printing method, intaglio offset printing method, flexographic printing method and the like. Of these methods, the screen printing method and the like are preferable.

  After application, the film may be baked without being dried, but is preferably dried from the viewpoint of easily forming a uniform conductive film. The drying method may be natural drying or may be dried by heating. The heating temperature is, for example, about 50 to 300 ° C, preferably about 80 to 200 ° C, and more preferably about 100 to 150 ° C. The heating time is, for example, about 1 minute to 3 hours, preferably about 5 minutes to 2 hours, and more preferably about 10 minutes to 1 hour.

  The firing temperature is equal to or higher than the softening point of the glass frit and lower than the heat resistance temperature of the glass substrate. The firing temperature (peak temperature) is, for example, about 400 ° C. or more (for example, 400 to 1000 ° C.), preferably 450 to 800 ° C., more preferably about 500 to 700 ° C. (especially 550 to 650 ° C.). The heat treatment time (heating time) may be, for example, 1 minute to 3 hours, preferably 5 minutes to 1 hour, more preferably about 10 to 30 minutes, depending on the heat treatment temperature and the like.

  As a method for forming the plating layer, a conventional plating method can be used, and electroplating, electroless plating, or the like is preferable because a plating layer can be selectively formed on the metal phase of the conductive layer. The electroplating method is not particularly limited, and may be performed under the conditions recommended by conventional plating chemical manufacturers according to the type of plating. The method of electroless plating is not particularly limited, and may be performed under conventional conditions depending on the type of plating.

  Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to these examples. The materials and instruments used are shown below.

[Materials and equipment used]
Glass substrate: “D263T” manufactured by Schott
Silver powder (SPN20J): “SPN20J” manufactured by Mitsui Mining & Smelting Co., Ltd., average particle size D50: 1.82 μm
Bi-based glass frit (GF3535): Bi ₂ O ₃ —SiO ₂ —R ₂ O (in the formula, R ₂ O = Li ₂ O, Na ₂ O, K ₂ O), Okuno Pharmaceutical Co., Ltd. “GF3535” manufactured, specific gravity 4.9
Bi glass frit (GF3440): Bi ₂ O ₃ —ZnO ₂ —B ₂ O ₃ , “GF3440” manufactured by Okuno Pharmaceutical Co., Ltd., specific gravity 6.6
Organic binder: Ethyl cellulose, sold by Nihon Kasei Co., Ltd. “EC-200FTD”
Screen printer: Murakami Co., Ltd., stainless mesh (mesh count: 325, emulsion 10 μm)
Hot air circulation oven: “FC-410” manufactured by ADVANTEC
Belt furnace: manufactured by Koyo Thermo System Co., Ltd.

[Example 1]
(Preparation of conductive paste for conductive layer)
100 g of silver powder, 20 g of Bi glass frit (GF3535), and 51 g of organic binder were kneaded in an automatic mortar to prepare a conductive paste. The volume ratio of Bi glass frit is 30% by volume with respect to the total amount of silver powder and Bi glass frit.

(Formation of conductive layer)
The obtained conductive paste was screen-printed on a glass substrate, dried in a hot air circulating oven at 120 ° C. for 30 minutes, and then set at a peak temperature of 600 ° C. for 10 minutes (In-Out 60 minutes). Firing was performed in a furnace to obtain a laminate in which a sintered film (average thickness of 5 μm) of a conductive paste was formed on a glass substrate. As a result of surface observation using a scanning electron microscope, as shown in FIG. 1, the metal, the Bi-based glass, and the voids formed a “sea-island structure” or a “co-continuous structure”. Note that the portion that appears black in the photograph is a void.

(Formation of plating layer)
On the conductive layer of the obtained laminate, electroless plating was performed in the order of Ni plating film (average thickness 0.3 μm), Pd plating film (average thickness 0.1 μm), and Au plating film (average thickness 0.05 μm). To obtain a conductive laminate. As a result of surface observation with a scanning electron microscope, it was confirmed that the gold on the outermost surface formed a “network structure” as shown in FIG.

  The obtained conductive laminate was heated on a hot plate set at 260 ° C. for 30 seconds, then taken out of the hot plate and rapidly cooled to room temperature. When the conductive laminate was confirmed from the back side, no cracks or the like occurred in the glass.

  Furthermore, after conducting a thermal shock test (-55 ° C. to 150 ° C., 300 cycles), the laminate was confirmed from the back side, and no cracks or the like were generated in the glass.

[Example 2]
A Ni plating film (average thickness of 1.5 μm) and a Pd plating film (average thickness of 0.1 μm) were formed on the conductive layer of the laminate in which the sintered film of the conductive paste was formed on the glass substrate by the same method as in Example 1. 1 μm) and Au plating film (average thickness 0.05 μm) were applied in this order to obtain a conductive laminate. As a result of surface observation with a scanning electron microscope, it was confirmed that gold on the outermost surface formed a “network structure” as in Example 1.

  The obtained conductive laminate was heated on a hot plate set at 260 ° C. for 30 seconds, then taken out of the hot plate and rapidly cooled to room temperature. When the conductive laminate was confirmed from the back side, no cracks or the like occurred in the glass.

  Furthermore, after conducting a thermal shock test (-55 ° C. to 150 ° C., 300 cycles), the laminate was confirmed from the back side, and no cracks or the like were generated in the glass.

[Comparative Example 1]
(Preparation of conductive paste for conductive layer)
100 g of silver powder, 1 g of Bi glass frit (GF3440) and 10 g of organic binder were kneaded in an automatic mortar to prepare a conductive paste. The volume ratio of Bi glass frit is 1.55 volume% with respect to the total amount of silver powder and Bi glass frit.

(Formation of conductive layer)
Using the obtained conductive paste, a laminate in which a sintered film (5 μm) of the conductive paste was formed on the glass substrate in the same manner as in Example 1 was obtained. As a result of surface observation with a scanning electron microscope, as shown in FIG. 3, the sea-island structure of metal and Bi-based glass was not seen in the sintered film. In the photograph, the hole is a void, and the other region is a region where the metal and the Bi-based glass are uniformly sintered.

(Formation of plating layer)
On the conductive layer of the obtained laminate, electroless plating was performed in the same manner as in Example 1 to obtain a conductive laminate. As a result of surface observation using a scanning electron microscope, as shown in FIG. 4, it was confirmed that a uniform nickel-plated film (a nickel-plated film whose surface was coated with gold) without a network structure was formed. .

  The obtained conductive laminate was heated on a hot plate set at 260 ° C. for 30 seconds, then taken out of the hot plate and rapidly cooled to room temperature. When the state of the conductive laminate was confirmed, cracks were generated in the glass, and the cracks extended with the passage of time, so that practical use as a circuit board was difficult.

[Reference Example 1]
A Ni plating film (average thickness 5 μm), a Pd plating film (average thickness 0.1 μm), and Au plating are formed on a laminate in which a conductive paste sintered film is formed on a glass substrate in the same manner as in Example 1. Electroless plating was performed in the order of the film (average thickness 0.05 μm) to obtain a conductive laminate. As a result of surface observation with a scanning electron microscope, it was confirmed that a uniform nickel-plated film (a nickel-plated film whose surface was coated with gold) without a network structure was formed. That is, by growing the nickel plating film too thickly, a plating film is generated even in the gap of the conductive layer and the Bi-based glass part, the gap is reduced, and finally the plating film with a gap filled (not meshed) It is had.

  The conductive laminate of the present invention includes, for example, electrodes such as a plasma display panel (PDP), a fluorescent display tube (VFD), a liquid crystal display (LCD), an organic electroluminescence display (ELD), and a touch panel display device. It can be used as a conductive film used in an RFID tag, an electromagnetic wave shield, a home or learning wiring kit, and the like.

Claims (11)

  A conductive laminate comprising a glass substrate, a conductive layer laminated on the glass substrate, and a plating layer laminated on the conductive layer, wherein the conductive layer comprises a metal and a low melting point glass. And a conductive laminate having a phase separation structure including a continuous phase formed of the metal.   2. The conductive laminate according to claim 1, wherein the phase separation structure of the conductive layer is a co-continuous structure or a sea-island structure, and the plating layer is laminated on the continuous phase formed of metal.   The conductive laminate according to claim 1 or 2, wherein the plating layer has a porosity of 40 to 90%.   The volume ratio of a metal and low melting glass is the former / the latter = 93 / 7-50 / 50, The electroconductive laminated body in any one of Claims 1-3.   The conductive laminate according to claim 1, wherein the softening point of the low-melting glass is lower than the firing temperature of the conductive layer.   The conductive laminate according to any one of claims 1 to 5, wherein the low-melting glass is a fired product of bismuth-based glass frit.   The conductive laminate according to claim 1, wherein the metal of the conductive layer is silver.   The electroconductive laminated body in any one of Claims 1-7 in which a plating layer contains nickel.   The conductive laminate according to claim 1, wherein the average thickness of the plating layer is 0.3 to 2 μm.   A conductive layer forming step of forming a conductive layer by applying a conductive layer precursor containing metal particles and glass frit on a glass substrate and then baking, a plated layer forming a plated layer by plating a metal on the conductive layer The manufacturing method of the electroconductive laminated body in any one of Claims 1-9 including a formation process.   The manufacturing method according to claim 10, wherein the conductive layer precursor further contains an organic binder.