JPH1166957A - Conductor composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide paste to form a baked film which has a film thickness of a specific range and is dense and has no pinhole and is excellent in plane smoothness by dispersing noble metal colloidal particles which have an average particle diameter of an undefined specific range and are sliver, gold, palladium, silver-palladium alloy and mixed powder of sliver and palladium, in an organic vehicle. SOLUTION: An excellent baked film having a film thickness of 1.5 to 3 μm is formed of noble metal colloidal particles having an average particle diameter of 0.01 to 0.17 μm. The noble metal colloidal particles are desirable to be not less than 50 pts.wt. in a metallic component in a colloidal solution and to be 40 to 70 pts.wt. in a conductor composition. An organic vehicle is formed by dissolving a resin component such as ethyl cellulose, nitro cellulose, acrylic ester, methacrylic acid ester and a photosensitive resin in an organic solvent such as butyl carbitol, pine oil, turpentine oil and diethyle phthalate, and desirably contains a metallic soap solution of an octyl acid and a naphthenic acid.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma display panel (PDP), a hybrid IC,
The present invention relates to a conductor composition (hereinafter, referred to as a noble metal paste) composed of fine particles of a noble metal colloid used for forming electrodes such as internal and external electrodes of a laminated chip component.

[0002]

2. Description of the Related Art In recent years, the application technology of noble metal pastes for the electronic industry has been rapidly expanding, and various kinds of noble metals are used singly or in combination. The noble metal paste is obtained by kneading and dispersing a noble metal powder or a noble metal organometal as a conductive functional material into a viscosity imparting medium made of an organic or inorganic binder or a metal oxide to form a paste.

As a method of forming a metal film on electrodes, conductors, and resistors of electronic components, a method of forming a metal film from a base metal or a noble metal organometal (ink), or a method of forming a thin film by wet plating typified by electroplating. Way, also
There are a method of forming a thin film by dry plating such as a vacuum evaporation method, a chemical vapor deposition method, and sputtering, and a thick film method of forming a metal film using a base metal or a noble metal paste. According to the conventional concept, when an electrode film is formed with a paste made of an organometallic material, a single printing process requires 0.5%.
It was difficult to obtain a fired film thickness of μm or more, and sufficient electric conduction could not be obtained.

The present invention does not rely on organometals or pastes using existing noble metal powders, but rather on the selection of new methods. Conventional electrode forming pastes have an average particle size of 0.5 to 4
It has been customary to use spherical or flake-shaped noble metal powder of μm. On the other hand, the present invention means that noble metal colloid fine particles having a specific particle diameter are selected and used as a paste for forming electrodes such as PDPs, various hybrid ICs, and internal and external electrodes of a laminated chip component.

Conventionally, a noble metal paste such as gold or silver is
500-100 after screen printing on glass substrate such as soda lime or ceramic substrate such as alumina
It is baked at 0 ° C., but it is necessary to make the baked film thickness 5 μm or less, to obtain a dense baked film, and to suppress the surface roughness to 0.1 μm or less in center line average roughness (Ra). It was difficult.

In the production of PDP, an auxiliary electrode is formed on a transparent electrode by using a silver paste. The auxiliary electrode is preferably formed thin and smooth as long as it does not hinder electric conduction. This is because a glass layer is formed as a dielectric layer on the auxiliary electrode, so that when the film thickness of the auxiliary electrode is increased, the thickness of the glass layer is effectively reduced and the withstand voltage of the glass layer is reduced. .

It is desirable that the surface of the auxiliary electrode be as smooth as possible for the same reason. However, the conventional gold or silver paste lacks the smoothness of the surface of the fired film, and cannot obtain a dense fired film with a fired film thickness of 5 μm or less.
Accordingly, the conductive resistance value also increases. The cause is that the particle size of the noble metal used for the noble metal paste is as large as 0.5 to 4 μm. Therefore, when firing in the range of 500 ° C. to 600 ° C., sintering does not proceed sufficiently and the surface is roughened and pinholes increase. That's why.

In the case where a fine pattern having a width of 50 μm or less is formed by photoetching, the denseness of the fired film must be more complete. In a fired film having many pinholes, the finer the pattern to be processed, the more the disconnection is likely to occur. Even if the disconnection does not occur, the conductive resistance of the formed pattern increases.

The conductive pattern electrode using a noble metal paste disclosed in Japanese Patent Application Laid-Open No. HEI 3-234085 is disclosed in Japanese Patent Application Laid-Open No. HEI 3-234085. This is to form a pattern electrode, but this is to roughen the electrode surface and increase the adhesion to other materials formed on the top of the electrode. Pinholes and smoothness are not particularly problematic. It is. Both are similar in precious metal print composition,
The purpose of use of the noble metal paste and the embodiment are irrelevant to the present invention.

Japanese Patent Application Laid-Open No. 8-262906 discloses an electrode ring of a heat roller for fixing toner in electrophotographic production of a printer or the like, and describes that gold or other silver colloid is used as a paste for forming a conductive layer. Have been. This has a problem of preventing cracks and joining. The fired paste film has a high conductive resistance, and does not mention details of the paste composition and metal particles.

[0011]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned various problems, and the film thickness of the organometallic (ink) in the conventional method is too thin, and that in the thick film method is too thick. It is an object of the present invention to provide a noble metal paste which has a sufficient denseness even with a fired film thickness of 5 to 3 μm and can form a fired film having no pinholes and excellent surface smoothness.

[0012]

The solution of the present invention is as follows. 1. A conductor composition obtained by dispersing noble metal colloid fine particles in an organic vehicle in a noble metal paste for forming a conductor, a resistor, and an electrode of an electronic component. 2. The conductor composition according to item 1, wherein the noble metal colloid fine particles are silver. 3. The conductor composition according to the above 1, wherein the noble metal colloid fine particles are gold, palladium, a silver / palladium alloy, or a mixed powder of silver and palladium. 4 Noble metal colloid fine particles have an average particle diameter of 0.01 to
4. The conductor composition according to any one of items 1 to 3, wherein the thickness is 0.1 μm. (5) The conductor composition according to any one of (1) to (4) above, wherein the noble metal colloid fine particles have an irregular particle shape. 6. The noble metal colloid fine particles are at least 50 parts by weight of the noble metal component in the conductor composition,
6. The conductor composition according to any one of 5. 7 Noble metal colloid fine particles are contained in the conductor composition in an amount of
7. The conductor composition according to any one of items 1 to 6, wherein the conductor composition contains parts by weight. (8) The conductor composition according to the above (1), wherein the conductor composition contains a metal soap solution. 9. The conductor composition according to any one of the above items 1 and 8, wherein the metal soap solution is an octylic acid-based or naphthenic acid-based metal salt. 10 The metal soap solution is octylic acid based on lead, zinc, zirconium, tin, iron, cadmium, nickel, bismuth,
10. The conductor composition according to any one of items 1, 8, and 9, comprising at least one of manganese and cobalt metal. 11 The metal soap solution contains naphthenic acid based on lead, zinc, iron,
11. The conductor composition according to any one of the above items 1, 8 to 10, comprising at least one of cadmium, lithium, magnesium, bismuth, manganese, cobalt, and copper metal. 12 The metal soap solution is based on 100 parts by weight of noble metal.
12. The conductor composition according to any one of the above items 1, 8 to 11, wherein the amount is 0.1 to 10 parts by weight in terms of metal. 13. Organic vehicles include ethyl cellulose, nitrocellulose, acrylates, methacrylates,
A resin component such as a photosensitive resin is dissolved in an organic solvent such as butyl carbitol, pine oil, terpineol, and diethyl phthalate.
13. The conductor composition according to any one of 12. 14 Organic vehicle is based on 100 parts by weight of noble metal
1 to 1 above, wherein 40 to 110 parts by weight are used.
4. The conductor composition according to any one of 3. (15) The conductor composition is a noble metal paste for forming an electrode of a plasma display panel.
15. The conductor composition according to any one of items 14 to 14. 16. The conductor composition is a noble metal paste for forming an electrode of a plasma display panel, wherein the fired film has a thickness of 1.5 to 3 μm, a surface roughness of 0.1 μm or less, and further covers the upper surface with glass. 16. The conductor composition according to any one of 1 to 15.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, a metal soap solution has an additional effect of improving adhesion strength, controlling color development on the back surface when using a glass substrate, controlling sintering of colloidal fine particles, and the like. Is added in an amount of 0.1 to 10 in terms of metal with respect to 100 parts by weight of noble metal.
The precious metal colloid fine particles preferably have a particle diameter of 0.01 to 0.1 μm.

The organic vehicle is obtained by dissolving a resin such as ethyl cellulose, nitrocellulose, acrylate, methacrylate, or photosensitive resin in an organic solvent such as butyl carbitol, pine oil, terpineol, or diethyl phthalate. desirable. Their blending amounts are selected so as to form a fired film thickness of 1.5 to 3.0 μm in one printing and firing step while maintaining good screen printability, and a range of 40 to 110 parts by weight in the paste. It is preferable to use them.

The noble metal paste of the present invention having the above structure is printed on a glass or ceramic substrate, dried, and then baked at 500 to 1000 ° C. to obtain a baked film having a baked film thickness of 1.5 to 3.0 μm. In addition, a dense noble metal film can be formed. In other words, a thin film is formed by a thick film method using a noble metal paste. Further, by repeating printing and drying, it is also possible to obtain a film having a more desired baked film thickness. Also, by adding a metal soap solution, the sintering of the colloid fine particles is controlled,
Oversintering can be suppressed and a thin and dense fired film can be obtained.

As a metal soap solution, octylic acid is
Lead, zinc, zirconium, tin, iron, cadmium, nickel, bismuth, manganese, cobalt metal, and naphthenic acid based lead, zinc, iron, cadmium, lithium, magnesium, bismuth, manganese, cobalt , Copper metal, and mainly uses lead octylate and bismuth naphthenate in many cases. Also,
Even if the metal soap solution is not added, it is possible to secure the adhesion strength equivalent to the tape peel test.

The use of 40 to 70 parts by weight of the noble metal colloidal fine particles means that if it is 40 parts by weight or less, a smooth continuous film is not easily formed on the electrode substrate, and a hole is formed,
The conductor resistance is also undesirably increased, and if it exceeds 70 parts by weight, the film thickness becomes unnecessarily thick, and waste is increased both electrically and economically. In addition, a uniform intended noble metal colloid liquid cannot be obtained.

The noble metal used in the paste of the present invention has a uniform effect even if it is gold, silver, palladium, a silver-palladium alloy, or a mixed powder of silver and palladium. The most preferred embodiment is silver, but the same effect can be obtained if the noble metal is contained in the colloid component in an amount of 50 parts by weight or more.

In the present invention, it should be noted that 0.01 to
By using silver colloid fine particles of 0.1 μm, a thickness of 1 to 3 μm, which was considered to be extremely difficult from the conventional concept,
Thus, a fired electrode film having no pinholes and having high smoothness could be easily formed. The shape of the noble metal colloid fine particles used in the implementation is irregular, and flakes, spheres, and other shapes of particles and particle diameters may be mixed, and the important point is that the particle diameter of the fine particles is as described above. .

In terms of applications, the present invention relates to a PDP
Is a noble metal paste for electrodes, for example, a fired film thickness of 1.5 to 3 μm, a surface roughness of 0.1 μm or less, and is also suitable for an auxiliary electrode or the like that further covers the upper surface with glass,
Needless to say, it is also used for forming electrodes such as internal and external electrodes of hybrid ICs and laminated chip components.

[0021]

EXAMPLE A silver colloid particle having a silver particle diameter of 0.1 μm, an organic vehicle, and a metal soap solution were mixed at the ratios shown in Table 1 to form a paste. The organic vehicle used was ethyl cellulose dissolved in terpineol. As the metal soap solution, a solution obtained by dissolving lead octylate soap in mineral spirits is used. These silver pastes were printed on a soda-lime glass substrate using a screen mesh # 325, dried at 120 ° C, and fired at 550 ° C, to form a silver film having a fired film thickness of 1.5 to 3.0 µm.

With respect to these silver films, the densities of the films were evaluated by a transmission electron microscope, the smoothness of the films was examined using a surface roughness meter, and the center line surface roughness (Ra) was evaluated. Also,
The adhesion was evaluated by a tape peel test. The results are shown in Table 1 below (next page). From these results, the silver films manufactured according to the examples of the present invention all have a thickness of 3.0.
It is very smooth, having a Ra of 0.1 μm or less and having an Ra of 0.1 μm or less, and is excellent in denseness of the film. On the other hand, it can be seen that the film thickness, surface smoothness and denseness of the comparative example are inferior. In this example, the silver electrode was evaluated as an example. However, the same effects as those of the above-mentioned other noble metals can be obtained depending on the application and specifications, which are also included in the present invention.

FIGS. 1 to 3 show transmission electron micrographs of a silver paste composed of silver colloidal fine particles used in Examples of the present invention. FIG. 1 shows 50,000 times magnification, and FIGS. 2 and 3 each show silver colloid fine particles magnified 200,000 times. The fine particles have a diameter of 0.01 to 0.1 μm, and it can be seen that the particles are amorphous. it can.

[0024]

[Table 1] * 1 Bismuth metal soap solution (bismuth concentration 25%)

[0025]

As described in detail above, when a noble metal according to the present invention, particularly silver, is used, a paste containing specific colloidal fine particles is used. Conductive composition made of other noble metal colloidal fine particles, which is extremely thin as 3 μm, has excellent smoothness and denseness, has no pinholes, has no remarkable action such as no disconnection or electrical loss, and has a low conductive resistance. Also, depending on its use and specifications, a thin film can be formed as long as the particle diameter is in the range of 0.01 to 0.1 μm, and the same effect as silver can be obtained.

[0026]

[Brief description of the drawings]

Fig. 1 Conductive composition (noble metal paste) in an embodiment of the present invention
Transmission electron micrograph (magnification: 50,000 times) of Fig. 2 Same photograph (magnification: 200,000 times) Fig. 3 Same photograph (magnification: 200,000 times)

Claims (16)

[Claims] 1. A conductive composition comprising a noble metal colloidal fine particle dispersed in an organic vehicle in a noble metal paste for forming a conductor, a resistor, and an electrode of an electronic component. 2. The conductor composition according to claim 1, wherein the noble metal colloid fine particles are silver. 3. The conductor composition according to claim 1, wherein the noble metal colloid fine particles are gold, palladium, a silver / palladium alloy, or a mixed powder of silver and palladium. 4. The precious metal colloid fine particles have an average particle diameter of 0.01 to 0.1 μm.
4. The conductor composition according to any one of items 1 to 3. 5. The conductor composition according to claim 1, wherein the noble metal colloid fine particles have an irregular particle shape. 6. The conductor composition according to claim 1, wherein the amount of the noble metal colloid fine particles is at least 50 parts by weight in the metal component in the colloid solution. 7. The conductor composition according to claim 1, wherein the noble metal colloid fine particles are contained in the conductor composition in an amount of 40 to 70 parts by weight. 8. The conductor composition according to claim 1, wherein the conductor composition contains a metal soap solution. 9. The conductor composition according to claim 1, wherein the metal soap solution is an octylic acid-based or naphthenic acid-based metal salt. 10. The metal soap solution, wherein the octylic acid is lead,
Zinc, zirconium, tin, iron, cadmium, nickel,
10. The conductor composition according to claim 1, comprising at least one of bismuth, manganese, and cobalt metal. 11. The metal soap solution, wherein the naphthenic acid is lead,
The conductor composition according to any one of claims 1, 8 to 10, comprising at least one of zinc, iron, cadmium, lithium, magnesium, bismuth, manganese, cobalt, and copper metal. 12. The conductor composition according to claim 1, wherein the metal soap solution is 0.1 to 10 parts by weight in terms of metal with respect to 100 parts by weight of noble metal. Stuff. 13. The organic vehicle is ethyl cellulose,
A resin component such as nitrocellulose, acrylic acid ester, methacrylic acid ester, and photosensitive resin is dissolved in an organic solvent such as butyl carbitol, pine oil, terpineol, and diethyl phthalate. 13. The conductor composition according to any one of 12. 14. The conductor composition according to claim 1, wherein the organic vehicle is used in an amount of 40 to 110 parts by weight based on 100 parts by weight of the noble metal. 15. The conductor composition according to claim 1, wherein the conductor composition is a noble metal paste for forming an electrode of a plasma display panel. 16. The conductive composition has a fired film thickness of 1.5 to 3 μm.
m, a precious metal paste for forming electrodes of a plasma display panel, wherein the surface roughness is 0.1 μm or less and the upper surface is further covered with glass.
The conductor composition according to any one of the above.