JPH0823154A - Formation of gold conductor - Google Patents

Abstract

PURPOSE:To provide formation of gold conductor so as to accurately form a gold conductor film of a required sizes only on the necessary parts on a fine interconnection pattern. CONSTITUTION:On a 96% baked alumina substrate 1, an unbaked interconnection pattern is formed by using thick film conductor paste for interconnection by screen printing. Then, interconnection conductor 2 is formed by baking the unbaked interconnection pattern. A load of 1g is applied to a part on the baked interconnection conductor 2 whereupon a gold conductor film is to be formed by using a pin 5 whose diameter at the tip is 0.05mm, and a recessed part 9 is formed. Then, an unbaked gold conductor film is formed in the recessed part 9 on the interconnection conductor 2 using the thick film gold conductor paste by screen printing. Then, the unbaked gold conductor film is baked and a gold conductor film 4 is formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a gold conductor for manufacturing a ceramic wiring board on which a bare IC chip is mounted.

[0002]

2. Description of the Related Art In order to mount a bare IC chip on a wiring board, a gold conductor is required for wire bonding and connection reliability with a gold bump. Generally, in order to form a gold conductor, a method in which gold is plated on a copper conductor wiring, or a wiring is provided by screen printing on the surface of a ceramic substrate with a thick film gold paste and then baked is adopted.

[0003]

However, in gold plating, the process becomes complicated and there is a problem of waste liquid treatment. In addition, since the substrate is solution-processed, it may cause deterioration of the performance of the substrate.

Further, in the thick film method, although the process is simple, if all the wirings are made of a gold conductor, the cost will be high. Therefore, in order to reduce the amount of the gold conductor paste used as much as possible, it suffices to form the gold conductor only at the place where wire bonding is performed or the place where it is connected to the gold bump. However, there is a problem in that the gold conductor paste slips on the electrodes and the gold conductor pattern is bleeding.

In order to solve the above problems in the prior art, the present invention provides a method for forming a gold conductor capable of accurately forming a gold conductor film of a required size only in a required place on a fine wiring pattern. The purpose is to do.

[0006]

In order to achieve the above object, a first method of forming a gold conductor according to the present invention is a method of forming a conductor in a fired ceramic substrate on which a fired conductor wiring is formed. After forming a recess at a desired location on the wiring and forming an unbaked gold conductor film in the recess,
The gold conductor film is fired.

A second method of forming a gold conductor according to the present invention is to form an unfired wiring pattern in a desired region on the ceramic substrate by using a thick film conductor paste in the fired ceramic substrate, After forming a recess at a desired location on the unfired wiring pattern, firing the unfired wiring pattern, then forming an unfired gold conductor film in the depression, and then firing the gold conductor film. It has a configuration.

In the first or second configuration of the method of the present invention, it is preferable that the recess is formed on the wiring conductor by pressing with a needle tip having a tip diameter of 0.1 mm or less.

Further, in the first or second structure of the method of the present invention, it is preferable to form the concave portion on the wiring conductor by laser processing.

In the first or second configuration of the method of the present invention, it is preferable to use a gold paste composition containing gold powder as a main component and at least an organic binder and a solvent as a material for the gold conductor film. Furthermore, the gold paste composition is attached to a needle tip having a slit with a diameter of 0.1 mm or less, and the gold paste composition is transferred to the concave portion on the conductor wiring to obtain unbaked gold. It is preferable to form a conductor film.

[0011]

According to the first structure of the method of the present invention, even if the gold conductor film is formed on the wiring conductor in a small area, the gold conductor film does not slip on the wiring conductor. There is no bleeding. Further, since the gold conductor film is formed in the recess of the wiring conductor, the thickness of the gold conductor film can be increased.

Further, according to the second structure of the method of the present invention, since the concave portion is formed in the wiring pattern (wiring conductor) before firing, the concave portion can be easily formed.

Further, in the first or second structure of the method of the present invention, according to a preferable structure, the recess is formed on the wiring conductor by pressing with a needle tip having a diameter of 0.1 mm or less. The recess can be formed on the wiring conductor by a simple operation.

Further, in the first or second configuration of the method of the present invention, according to the preferred configuration in which the recess is formed on the wiring conductor by laser processing, stress is less likely to be applied to the edge of the recess, so that a clean shape is obtained. Can be formed.

In the first or second configuration of the method of the present invention, the gold conductor film is preferably composed of a gold paste composition containing gold powder as a main component and at least an organic binder and a solvent. According to this, since the gold conductor film can be formed by screen printing,
The gold conductor film can be formed in a smaller number of processing steps as compared with the case where the gold conductor film is formed by plating or the like, and as a result, workability can be improved. In this case, the gold paste composition is further attached to a needle tip having a slit at the tip and a diameter of 0.1 mm or less, and the gold paste composition is transferred to the concave portion on the conductor wiring, whereby the unfired According to the preferable configuration of forming the gold conductor film, a large amount of the thick film gold paste can be sucked up to the needle tip by the capillary phenomenon due to the slit, so that the transfer of the thick film gold paste is performed several times by one supply. As a result, workability can be improved.

[0016]

EXAMPLES The present invention will be described in more detail below with reference to examples. (Embodiment 1) FIG. 1 is a process drawing showing an embodiment of a method for forming a gold conductor according to the present invention.

In FIG. 1, 1 is a fired ceramic substrate, 2 is a wiring conductor, 4 is a gold conductor film, and 5 is a pin.
First, as shown in FIG. 1A, a thick film conductor paste for wiring (QP1
53: manufactured by DuPont) was used to form an unfired wiring pattern by screen printing, and then the unfired wiring pattern was fired to form the wiring conductor 2.

Then, as shown in FIG. 1 (b), a load of 1 g is applied to a portion of the baked wiring conductor 2 where a gold conductor film is to be formed by a pin 5 having a tip diameter of 0.05 mm. The recess 9 was formed. Pin 5 like this
Since the concave portion 9 is formed by using, it is possible to form the concave portion 9 on the wiring conductor 2 by a simple operation.

Next, as shown in FIG. 1 (c), an unfired gold conductor film is formed by screen printing using a thick film gold conductor paste in the recess 9 on the wiring conductor 2 and then fired to form the gold conductor. The film 4 was formed. Here, the thick-film gold conductor paste was 88.0% by weight of gold powder (manufactured by Tanaka Kikinzoku International Co., Ltd.) having an average particle size of 0.6 micron, and divanadium pentoxide powder (reagent manufactured by Kanto Chemical Co., Inc.); 0. .6% by weight
And cupric oxide powder (CB50: manufactured by Kyoto Elex Co., Ltd.); 1.0 wt% and acrylic resin; 4.0 wt%
And terpineol; 6.4% by weight.

As described above, since the unfired gold conductor film is formed on the wiring conductor 2 having the recess 9 by using the thick film gold conductor paste, the gold conductor paste is formed on the wiring conductor 2. Even if a small area is formed, the gold conductor paste does not slip on the wiring conductor 2, and as a result, the gold conductor pattern does not bleed. Moreover, since the gold conductor film 4 is formed in the recess 9 of the wiring conductor 2, the gold conductor film 4 is formed.
You can also earn the thickness of. Further, since the gold conductor paste is used as the material of the gold conductor film 4, the gold conductor film 4 can be formed by screen printing as described above, and as a result, the gold conductor film 4 is formed by plating or the like. Since the gold conductor film 4 can be formed by a smaller number of processing steps than in the case, workability can be improved.

As a comparative example, as shown in FIG. 4, when the unfired gold conductor film 8 was formed on the wiring conductor 2 having no recess by using the thick film gold conductor paste, the unfired gold conductor film 8 was formed. It flowed on the wiring conductor 2 and was blurred.

In the first embodiment, the concave portion 9 is formed by using the pin 5 having the tip diameter of 0.05 mm, but it is not limited to this diameter.
Those having a thickness of 0.1 mm or less can be appropriately used depending on the design.

(Embodiment 2) FIG. 2 is a process drawing showing another embodiment of the method for forming a gold conductor according to the present invention. First, FIG.
As shown in (a), 96% calcined alumina substrate 1
A thick film conductor paste for wiring (QP153: made by DuPont) was used to form an unfired wiring pattern by screen printing, and then the unfired wiring pattern was fired to form the wiring conductor 2.

Next, as shown in FIG. 2B, YA is formed on the baked wiring conductor 2 at a position where a gold conductor film is to be formed.
The recess 9 was formed using a G laser. Since the recess 9 is formed on the wiring conductor 2 by the laser processing as described above, stress is less likely to be applied to the edge of the recess 9, and as a result, the recess 9 having a clean shape can be formed.

Next, as shown in FIG. 2 (c), an unfired gold conductor film is formed by screen printing using a thick film gold conductor paste in the recess 9 on the wiring conductor 2 and then fired to form the gold conductor. The film 4 was formed. Thus, the wiring conductor 2 before firing
Since the concave portion 9 is formed in the concave portion, the concave portion 9 can be easily formed as compared with the case of the first embodiment. Here, the same thick-film gold conductor paste as that used in Example 1 was used.

(Embodiment 3) FIG. 3 is a process drawing showing still another embodiment of the method for forming a gold conductor according to the present invention.

In FIG. 3, 6 is a needle having a slit at the tip and having a diameter of 0.1 mm, and 7 is a gold conductor paste. First, as shown in FIG. 3A, an unfired wiring pattern is formed on a 96% baked alumina substrate 1 by screen printing using a thick film conductor paste for wiring (QP153: manufactured by DuPont). After that, the unfired wiring pattern was fired to form the wiring conductor 2.

Next, as shown in FIG. 3 (b), a load of 1 g is applied to a portion of the baked wiring conductor 2 where a gold conductor film is to be formed by a pin 5 having a tip diameter of 0.05 mm. The recess 9 was formed.

Next, as shown in FIG. 3 (c), after the unbaked gold conductor film is transferred and formed in the recess 9 on the wiring conductor 2 by the needle 6 having the gold conductor paste 7 attached to the tip thereof, The gold conductor film 4 was formed by firing. Thus, after the gold conductor paste 7 is attached to the tip of the needle 6, the gold conductor paste 7 is transferred to the concave portion 9 on the conductor wiring 2 to form the unbaked gold conductor film 4. ,
By adhering the gold conductor paste 7 to the needle tip, a large amount of the gold conductor paste 7 can be sucked up by the capillary phenomenon by the slit. Therefore, the transfer can be performed several times by supplying the gold conductor paste 7 once.
Workability can be improved. Here, the same gold conductor paste 7 as in Example 1 was used.

In the third embodiment, the recess 9 is formed by using the pin 5 having a tip diameter of 0.05 mm, but the pin 9 is not limited to this diameter.
Those having a thickness of 0.1 mm or less can be appropriately used depending on the design.

In the third embodiment, the diameter is 0.
Although the unbaked gold conductor film is transferred using a 1 mm needle, it is not necessarily limited to this diameter, and one having a diameter of 0.1 mm or less is appropriately used depending on the size of the recess 9. be able to.

Further, in the first, second and third embodiments,
The case where the recess 9 is formed on the surface of the fired wiring conductor 2 has been described as an example, but the method is not necessarily limited to this method, and after the recess 9 is formed on the surface of the unfired wiring conductor 2. You may bake. Then, in this way, the recess 9
The concave portion can be easily formed by firing after forming.

[0033]

As described above, according to the first method of forming a gold conductor of the present invention, the first method of the present invention can be used.
According to the configuration, even if the gold conductor film is formed on the wiring conductor in a small area, the gold conductor film does not slip on the wiring conductor, so that the gold conductor pattern does not bleed. Further, since the gold conductor film is formed in the recess of the wiring conductor, the thickness of the gold conductor film can be increased.

Further, according to the second method for forming a gold conductor of the present invention, since the recess is formed in the wiring pattern (wiring conductor) before firing, the recess can be easily formed.

In the first or second configuration of the method of the present invention, according to a preferred configuration, the depression is formed on the wiring conductor by pressing with a needle tip having a diameter of 0.1 mm or less. The recess can be formed on the wiring conductor by a simple operation.

In the first or second structure of the method of the present invention, according to the preferable structure in which the recess is formed on the wiring conductor by laser processing, stress is less likely to be applied to the edge of the recess, so that a clean shape is obtained. Can be formed.

In the first or second configuration of the method of the present invention, the gold conductor composition is preferably composed of a gold paste composition containing gold powder as a main component and at least an organic binder and a solvent. According to this, since the gold conductor film can be formed by screen printing,
The gold conductor film can be formed in a smaller number of processing steps as compared with the case where the gold conductor film is formed by plating or the like, and as a result, workability can be improved. In this case, the gold paste composition is further attached to a needle tip having a slit at the tip and a diameter of 0.1 mm or less, and the gold paste composition is transferred to the concave portion on the conductor wiring, whereby the unfired According to the preferable configuration of forming the gold conductor film, a large amount of the thick film gold paste can be sucked up to the needle tip by the capillary phenomenon due to the slit, so that the transfer of the thick film gold paste is performed several times by one supply. As a result, workability can be improved.

[Brief description of drawings]

FIG. 1 is a process drawing showing an example of a method for forming a gold conductor according to the present invention.

FIG. 2 is a process drawing showing another embodiment of the method for forming a gold conductor according to the present invention.

FIG. 3 is a process drawing showing still another embodiment of the method for forming a gold conductor according to the present invention.

FIG. 4 is a schematic sectional view of a gold conductor formed by a conventional gold conductor forming method.

[Explanation of symbols]

 1 baked alumina substrate 2 wiring conductor 4 gold conductor film 5 pin 6 needle 7 gold conductor paste

Front page continuation (72) Inventor Yuhaku St. 1006 Kadoma, Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Yoshihiro Bessho, 1006 Kadoma, Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd.

Claims (6)

[Claims] 1. In a fired ceramic substrate having a fired conductor wiring formed on its surface, after forming a recess at a desired location on the conductor wiring and forming an unfired gold conductor film in the depression. And a method for forming a gold conductor by firing the gold conductor film. 2. In a fired ceramic substrate, a thick film conductor paste is used to form an unfired wiring pattern in a desired region on the ceramic substrate, and a recess is formed at a desired location on the unfired wiring pattern. After that, the unfired wiring pattern is fired, then an unfired gold conductor film is formed in the recess, and then the gold conductor film is fired. 3. The method for forming a gold conductor according to claim 1, wherein the recess is formed on the wiring conductor by pressing with a needle tip having a tip diameter of 0.1 mm or less. 4. The method for forming a gold conductor according to claim 1, wherein the recess is formed on the wiring conductor by laser processing. 5. The method for forming a gold conductor according to claim 1, wherein a gold paste composition containing gold powder as a main component and at least an organic binder and a solvent is used as a material for the gold conductor film. 6. A diameter of 0.1 with a slit at the tip.
The gold conductor composition according to claim 5, wherein an unfired gold conductor film is formed by depositing a gold paste composition on a needle tip of mm or less and transferring the gold paste composition to a recess on a conductor wiring. Method.