JPH10340619A - Low temperature firing gold paste - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an excellent gold film even if it is baked at a temperature not more than a heat resistant temperature of glass substrate by manufacturing it by kneading/dispersing gold particles having the specific particle size, glass frit having a softening point of a specific temperature and an organic vehicle. SOLUTION: The particle size of gold particles is set not more than 1.0 μm, and therefore, heat capacity of the individual gold particles is reduced, and sintering of the mutual gold particles is improved at baking time, and a resistance value does not become high. A softening point of glass frit is set not more than 450 deg.C, and therefore, when it is bake at 500 to 600 deg.C, the glass frit is excellently fixed between a glass substrate and a gold film, and adhesion strength is enhanced, and glass does not interpose as a resistor between the gold particles. Paste by kneading/dispersing a mixture of a prescribed rate of these gold particles, glass frit and organic vehicle by three rollers and a blender or the like, is printed, dried and baked on the glass substrate, and a gold film electrode or the like is obtained. Therefore, there is no necessity for divided processing and assembling of an expensive device and parts like an evaporation method.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a low-temperature firing paste capable of forming a gold film conductive circuit on a glass substrate or the like.

[0002]

2. Description of the Related Art In general, components such as a matrix electrode panel for a plasma display, a CCD sensor, and an image sensor are formed on a non-alkali glass or other various glass substrates by an evaporation method. In such a vapor deposition method, since the gold film is deposited by housing the electrode forming member in a vacuum vessel, the apparatus becomes large and expensive, and it takes a lot of time to evacuate and take in the member, and it takes time for evacuation. Not only is the workability not good, but also a masking step and an etching step for the members are required, and the cost is considerably high.

[0003]

Therefore, it has been desired to form a gold film electrode by printing a gold paste on a glass substrate and firing it. However, even if the conventional gold paste is baked at a temperature lower than the heat resistance temperature of the glass substrate, not only the adhesion to the glass substrate is poor, but also the wire-bonding non-adhesion rate is high, the conductor resistance value is high, and it cannot be used. .

Accordingly, an object of the present invention is to provide a low-temperature fired gold paste capable of forming a good gold film even when fired at a temperature lower than the heat resistance temperature of a glass substrate.

[0005]

An object of the present invention is to provide a low-temperature fired gold paste obtained by kneading and dispersing gold particles having a particle size of 1.0 μm or less, a glass frit having a softening point of 450 ° C. or less, and an organic vehicle. Achieved.

[0006]

According to the present invention, a gold film electrode is obtained by applying a paste on a glass substrate, drying and baking, instead of forming a gold film electrode by vapor deposition as in the prior art.
For kneading and dispersing the gold particles, the glass frit and the organic vehicle, a machine such as a three-roll or blender is used. When the gold particles are 1.0 μm or less as in the present invention, the particle size is about 以下 or less of the gold particles commonly used in the conventional gold paste, so that the volume is about ８ or less. The heat capacity of each particle is also extremely small, and even when fired at a temperature equal to or lower than the heat resistance temperature of the glass substrate, the gold particles sinter well and the resistance does not increase. By setting the softening point of the glass frit to 450 ° C. and firing at a temperature of 500 ° C. to 600 ° C., the glass frit is fixed well between the glass substrate and the gold film, and the adhesion strength is increased. Further, the glass does not intervene as a resistor between the gold particles.

[0007]

Example 1 91% by weight of gold particles having a particle size of 1.0 μm, 3.0% by weight of glass frit having a softening point of 450 ° C. or less composed of PbO—B ₂ O ₃ —SiO ₂ , and terpineol as ethyl cellulose Was mixed with 6.0% by weight of an organic vehicle dissolved in, and kneaded and dispersed using a three-roll mill or a blender to obtain a low-temperature fired gold paste. The gold paste obtained here is 325
After printing on a lime glass substrate through a mesh screen, baking was performed at a peak temperature of 550 ° C. and a peak time of 10 minutes. The gold film on the glass substrate obtained in such a process forms a mirror-like gold film in which the spaces between the gold particles are completely sintered.
The conductor resistance of the μm-thick gold film was 4.3 mΩ / □, and the nonbonding rate of wire bonding was 0%, which was a good result.

[0008]

Example 2 91% by weight of gold particles having a particle diameter of 0.6 μm, 3.0% by weight of a glass frit having a softening point of 450 ° C. or less, and 6.0% by weight of an organic vehicle were kneaded and dispersed to obtain a low-temperature fired gold paste. Was. When a gold film was provided on a glass substrate using the gold paste under the same conditions as in Example 1, the conductor resistance was 3.8 mΩ / □ for a 10 μm thick gold film, and the wire bonding non-adherence rate was 0%. there were. In the case of this embodiment, the gold particle diameter is smaller than that of the first embodiment.
Therefore, the volume or heat capacity of the gold particles is about 1/8, the sintering between the gold particles is further improved, and the change in the conductor resistance value also appears.

[0009]

Example 3 Low temperature obtained by kneading and dispersing 91% by weight of gold particles having a particle diameter of 0.2 μm, 3.0% by weight of a glass frit having a softening point of 450 ° C. or lower, and 6.0% by weight of an organic vehicle. When the baked gold paste was baked and fixed at a temperature of 550 ° C. on a glass substrate and evaluated, the conductor resistance value was 3.2 mΩ / □ for a 10 μm thick gold film, and the wire bonding non-adhesion rate was 0%. Was.

[0010]

Comparative Example 1 A gold paste obtained by kneading 91% by weight of gold particles having a particle diameter of 2.0 μm, 3.0% by weight of a glass frit having a softening point of 450 ° C. or lower, and 6.0% by weight of an organic vehicle was mixed with 325 mesh. When printed on a glass substrate through a screen and fired at 550 ° C., a mirror-like gold film was not obtained, and the conductor resistance was as high as 8.0 mΩ / □ at a thickness of 10 μm. The non-delivery rate was 100%, which proved unusable.

[0011]

Comparative Example 2 A gold paste obtained by kneading 91% by weight of gold particles having a particle diameter of 1.4 μm, 3.0% by weight of a glass frit having a softening point of 450 ° C. or lower, and 6.0% by weight of an organic vehicle was similarly prepared. After printing on a glass substrate through a 325 Messi screen, it was baked at 550 ° C. When this was evaluated, the conductor resistance value was 5.4 mΩ / □ at a thickness of 10 μm, and the wire bonding non-adhesion rate was 45%, so that a practically usable one was not obtained.

As is apparent from Comparative Examples 1 and 2, even when a glass frit having a softening point of 450 ° C. or lower is used, when a gold particle having a particle diameter of more than 1.0 μm is used, the gold particle is reduced. It can be seen that the sintering of each other is only partially and weakly performed, resulting in a rough sintered film having many pinholes, a high conductor resistance value of the sintered film, and it cannot be used as a conductor electrode. Conversely, if the softening point of the glass frit exceeds 450 ° C. even when the particle size of the gold particles is 1.0 μm or less, a sintered film of gold particles can be obtained, Since the adhesion strength to the glass substrate is small, or the glass frit is not melted while being interposed between the gold particles, the conductor resistance becomes high, so that it cannot be used. As described above, according to the present invention, gold particles having a particle size of 1.0 μm or less and a softening point of
By using a gold paste containing a glass frit of 0 ° C. or less, a gold fired film having good characteristics can be obtained even at a firing temperature as low as about 500 ° C. to 600 ° C.

[0013]

As described above, according to the present invention, a sintered gold film having good characteristics can be obtained even when the glass substrate is fired at a temperature lower than the allowable temperature limit. There is no need to use it, and it is not necessary to divide and assemble parts in a fine manner. This makes it possible to integrally form electrodes, conductive circuits, or dedicated LSIs on a glass substrate, which has the effect of reducing the size and cost of parts. Can be

Claims (1)

[Claims] 1. A low-temperature fired gold paste obtained by kneading and dispersing gold particles having a particle size of 1.0 μm or less, a glass frit having a softening point of 450 ° C. or less, and an organic vehicle.