JPH0613756A - Conductive paste composition - Google Patents

Abstract

PURPOSE:To bore a via-hole on a ceramic board through laser machining by a method wherein the ceramic multilayer wiring board is formed out of conductive paste composition containing specific components. CONSTITUTION:Conductive paste containing 50.0 to 75.0% by weight powdery conductor of silver, palladium, or alloy of them, 25.0 to 50.0% by weight inorganic component of silver oxide powder, and organic vehicle component composed of organic binder and solvent is used. A conductor layer 2 is formed on a base film 1 subjected to a releasing treatment out of the above wiring conductive paste through a screen printing method. Furthermore, an insulating layer 3 is formed out of insulator paste covering all the wiring pattern to form a transfer sheet 4. A via-hole 5 is bored in the transfer sheet 4 at a prescribed place by a carbon dioxide gas laser. In result, an excellent via-hole 5 can be formed by a carbon dioxide gas laser, and laser beam machining can be enhanced in machining speed and long-hour operation can be achieved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a conductor paste composition used for manufacturing a ceramic multilayer wiring board on which LSI, IC or chip parts are mounted.

[0002]

2. Description of the Related Art As a method for manufacturing a ceramic multilayer substrate, a green sheet laminating method and a thick film printing multilayer method are well known and widely used. The green sheet stacking method enables high stacking and fine wiring patterns, but on the other hand, it has drawbacks such as poor manufacturing yield and poor ability to change wiring patterns. Although it has good adaptability and good manufacturing yield, it has a problem that it is impossible to achieve high stacking and cannot cope with a fine wiring pattern because of a step on the substrate surface due to the wiring pattern. As a method that takes advantage of these two manufacturing methods, there has been proposed a method (transfer method) in which a transfer sheet having a structure in which a wiring pattern is embedded in an insulating layer is transferred and laminated on a ceramic substrate. On the other hand, an important point in the manufacturing technology of the ceramic multilayer substrate is the technology for connecting the wiring layers. Generally, in order to connect the wiring layers, a hole called a via hole is formed at a predetermined position on the wiring and the via hole is formed. The method of filling with a conductor material is taken.

[0003]

In the green sheet laminating method and the transfer method, the via holes are generally formed by a punching method or a die method. The former punching method is a method of forming via holes one by one by coordinate control by a computer, and has the disadvantages that the processing time is long and the punching pins are worn or broken. The latter mold method can process a plurality of via holes at one time by using the mold, but has the disadvantages that the mold cost is high and it is difficult to change the design. From the above, laser processing is considered to be the most effective for forming via holes, and studies have been vigorously conducted. FIG. 3 shows a state of laser processing when a conventional conductor paste composition is used. In FIG. 3, 1 is a base film,
Reference numeral 2 is a conductor layer, 3 is an insulating layer, 4 is a transfer sheet, and 5 is a via hole. As shown in the figure, the transfer sheet 4 has a structure in which a wiring pattern in which the main component of the conductor material is silver is embedded in the insulating layer 3.
When the via hole 5 is to be formed by laser processing, there is a problem that the processing is difficult, for example, silver reflects the laser and the hole diameter of the conductor layer 2 and the insulating layer 3 becomes small.

The present invention is intended to solve the above problems,
It is an object of the present invention to provide a conductor paste composition capable of forming via holes by laser processing.

[0005]

In order to achieve the above object, the conductor paste composition of the present invention is used as a conductor paste composition for vias, and a conductor material powder of 50.0 to 75.0% by weight is used.
And an inorganic component composed of 25.0 to 50.0% by weight of silver oxide powder, and an organic vehicle component composed of at least an organic binder and a solvent.

[0006]

Therefore, according to the present invention, 50.0 to 75.0% by weight of conductor material powder and 25.0% of silver oxide powder are used as the conductor.
Since a conductor paste composition comprising an inorganic component consisting of ˜50.0% by weight and an organic vehicle component consisting of at least an organic binder and a solvent is used, it is possible to form via holes by laser processing and improve processing speed. And continuous operation for a long time can be realized.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.
At the same time, the same parts as those in FIG. 3 are denoted by the same reference numerals, detailed description thereof will be omitted, and different points will be described. FIG. 1 is a schematic view of a cross section of a via hole punched by a carbon dioxide gas laser of a transfer sheet using the conductor paste composition of one embodiment of the present invention, and FIGS. 2 (a), 2 (b) and 2 (c) are It is a figure which shows the temperature profile of each process in the manufacturing method of the ceramic multilayer wiring board using the conductor paste composition of one Example of this invention.

(Example 1) As a raw material of a conductor paste,
Silver powder with an average particle size of about 1 micron (Fukuda Metal Foil Powder Co., Ltd.)
44.3% by weight, 44.3% by weight of silver oxide powder having an average particle diameter of 1 to 3 microns (manufactured by Hanai Chemical Co., Ltd.), and butyral resin + benzylbutyl phthalate as a binder.
0% by weight and 2.4% by weight of butyl carbitol as a solvent were prepared, respectively, and these were sufficiently mixed and kneaded with a three-roll to prepare a conductor paste for wiring.

Next, as a raw material for the conductor paste for vias,
Silver powder with an average particle size of about 1 micron (Fukuda Metal Foil Powder Co., Ltd.)
41.7% by weight, glass powder (Nippon Electric Glass Co., G
A13, softening temperature of 850 ° C.) is 41.7% by weight, ethylcellulose resin is 0.8% by weight as a binder, and terpineol is 15.8% by weight as a solvent. These are thoroughly mixed with a three-roll mill. Then, they were kneaded to prepare a conductor paste for vias.

Further, as a raw material of the insulating paste, 70% by weight of insulating powder (alumina + borosilicate glass powder), 15% by weight of butyral resin + benzyl benzyl phthalate as a binder and 15% by weight of butyl carbitol as a solvent. Were prepared, and these were sufficiently mixed and kneaded with a three-roll to prepare an insulating paste.

As shown in FIG. 1, a conductor layer (wiring pattern) 2 is formed on a base film (PET) 1 whose surface has been subjected to a mold release process by screen printing with the conductor paste for wiring prepared as described above. Further, an insulating layer 3 was formed so as to cover the entire wiring pattern with an insulating paste, and a transfer sheet 4 was produced. A transfer sheet 4 having a wiring pattern of each layer formed in the same order was prepared, and a via hole 5 was punched at a predetermined position of each transfer sheet 4 by a carbon dioxide laser. Next, the transfer sheet 4 is thermally transferred onto a 96% alumina substrate (not shown) under the conditions of 60 ° C. and 80 kg / cm ² , and the above-mentioned via conductor paste (not shown) is filled in the via holes 5 and then the base is formed. The film 1 was peeled off, and a plurality of transfer sheets 4 were laminated in the same order to obtain a laminate (not shown).

Next, the obtained laminated body was subjected to binder removal treatment in the atmosphere in a heating furnace. The heating conditions at this time are shown in FIG.
Peak temperature 275 ° C, peak temperature holding time 360
The temperature profile was minute.

After that, the laminate was sintered and fired in the air in the heating furnace. The heating conditions were such that the peak temperature was 900 ° C. and the peak temperature holding time was 10 minutes as shown in FIG. 2B. Finally, the uppermost wiring was formed by screen printing with a thick film conductor paste (DD2332H, manufactured by Kyoto Elex Co., Ltd.) and baked in the atmosphere. The heating conditions were a temperature profile having a peak temperature of 850 ° C. and a peak temperature holding time of 10 minutes shown in FIG.

As a comparative example to this example, a conductor paste containing only silver powder as an inorganic component containing no silver oxide was prepared, and a via hole 5 was similarly drilled by a carbon dioxide laser. As shown in FIG. The hole diameters of the conductor layer 2 and the insulating layer 3 were smaller than the hole diameter of the film 1, and the insulating layer 3 was bulged. The cause was that the carbon dioxide laser generated silver powder in the conductor layer 2. It is thought that such a via hole was formed due to the reflection.

(Example 2) As a raw material of the conductor paste,
Silver powder with an average particle size of about 1 micron (Fukuda Metal Foil Powder Co., Ltd.)
40.0% by weight, palladium powder having an average particle diameter of about 1 micron (manufactured by Fukuda Metal Foil Powder Co., Ltd.) 4.3% by weight, silver oxide powder having an average particle diameter of 1 to 3 microns (manufactured by Hanai Chemical Co., Ltd.) 4
4.3 wt%, butyral resin + benzyl butyl phthalate 9.0 wt% as a binder, and butyl carbitol 2.4 wt% as a solvent were prepared respectively, and these were thoroughly mixed and kneaded by a three-roll mill. Then, a conductor paste for wiring was prepared.

Next, as a raw material for the via conductor paste,
41.7% by weight of copper oxide powder (manufactured by Kyoto Elex Co., Ltd., CB250 crushed) having an average particle size of about 1 to 3 microns, glass powder (Nippon Electric Glass Co., Ltd., GA13, softening temperature 850)
41.7% by weight, ethyl cellulose resin as a binder 0.8% by weight, and terpineol 15.8% by weight as a solvent, respectively. These are thoroughly mixed and kneaded with a three-roll to prepare a beer. A conductor paste for use was prepared.

Further, as the raw material of the insulating paste, 70% by weight of the same insulating powder as in (Example 1) and 1% of butyral resin + benzylbutyl phthalate as a binder are used.
5% by weight, butyl carbitol as a solvent 15% by weight
Were prepared, and these were sufficiently mixed and kneaded with a three-roll to prepare an insulating paste.

As shown in FIG. 1, a conductor layer (wiring pattern) 2 is formed on a base film (PET) 1 whose surface is subjected to a mold release treatment, by screen printing with the conductor paste for wiring prepared as described above. Further, an insulating layer 3 was formed so as to cover the entire wiring pattern with an insulating paste, and a transfer sheet 4 was produced. A transfer sheet 4 having a wiring pattern of each layer formed in the same order was prepared, and a via hole 5 was punched at a predetermined position of each transfer sheet 4 by a carbon dioxide laser. Next, the transfer sheet 4 is thermally transferred onto a 96% alumina substrate (not shown) under the conditions of 60 ° C. and 80 kg / cm ² , and the via conductor paste (not shown) prepared as described above is placed in the via holes 5. After filling, the base film 1 was peeled off, and a plurality of transfer sheets 4 were laminated in the same order to obtain a laminate (not shown).

Next, the obtained laminated body was subjected to binder removal treatment in the atmosphere in the heating furnace. The heating conditions at this time were the same as those in (Example 1).

The laminated body was sintered and fired under the same conditions as in (Example 1) under the conditions for forming the uppermost wiring with the thick film conductor paste.

As a comparative example to this example, a conductor paste containing no silver oxide and containing only silver powder as an inorganic component was prepared, and the via holes 5 were similarly punched by a carbon dioxide gas laser. As shown in FIG. The result was similar to that of the comparative example in Example 1).

Further, the conductor paste composition was prepared by changing the ratio of silver and palladium, and the via hole 5 was similarly drilled by the carbon dioxide gas laser. When the palladium content was 20% by weight or more, it was oxidized. It was confirmed that the via holes 5 could be finely drilled by a carbon dioxide laser without containing silver, but it is considered to be unfavorable as a wiring board because the wiring resistance becomes higher when the palladium content increases.

In the examples, silver powder or a mixed powder of silver and palladium was used as the conductive component in the conductor paste composition, but it is also possible to use an alloy powder of silver and palladium.

[0024]

As is apparent from the above examples, the present invention is based on an inorganic component consisting of 50.0 to 75.0% by weight of conductor material powder and 25.0 to 50.0% by weight of silver oxide powder, and at least an organic component. Since the binder and the organic vehicle component made of a solvent are provided, an excellent via hole shape can be formed by laser processing, and the processing speed can be improved and continuous operation for a long time can be realized. Moreover, since the silver oxide used as the laser absorbing material becomes metallic silver by the heat treatment, the conductor resistance is not extremely increased.

[Brief description of drawings]

FIG. 1 is a partial sectional view of a transfer sheet obtained by using a conductor paste composition according to an embodiment of the present invention.

FIG. 2A is a relationship diagram showing a temperature profile of a binder removal step in the case of manufacturing a multilayer wiring board using the conductor paste composition of one embodiment of the present invention. FIG. 2B is the same sintering and firing step. (C) is a relationship diagram showing a temperature profile in the firing process of the thick-film conductor paste.

FIG. 3 is a partial sectional view of a transfer sheet obtained by using a conventional conductor paste composition.

[Explanation of symbols]

 1 Base Film 2 Conductor Layer 3 Insulating Layer 4 Transfer Sheet 5 Via Hole

Claims (2)

[Claims] 1. A conductor paste composition for use in manufacturing a ceramic multilayer wiring board, comprising 50.0 to 50% of conductor material powder.
75.0% by weight and silver oxide powder 25.0-50.0% by weight
2. A conductor paste composition comprising an inorganic component consisting of and an organic vehicle component consisting of at least an organic binder and a solvent. 2. The conductor paste composition according to claim 1, wherein the conductor material is silver, palladium or an alloy thereof.