JPH04316394A - Manufacture of ceramic thick film wiring circuit board - Google Patents

Abstract

PURPOSE:To accurately align two or more types of wiring patterns by printing paste to be baked in an oxidative atmosphere with at least two positioning through holes or viaholes provided on a surface of a ceramic board as a reference. CONSTITUTION:Through holes or viaholes 3 for electrically connecting or positioning a lower wiring layer are provided at predetermined positions on a surface of a ceramic board 2. After gold pattern-forming patterns are printed on the surface of the board 2 at least with the two through holes or the viaholes 3 as a reference of the positions, they are baked in an oxidative atmosphere, and gold conductors 5 of gold pads, etc., are formed. After resistors, etc., to be baked in the atmosphere are printed necessary times, they are baked and formed. Eventually, after copper paste is printed at predetermined positions, they are baked in a nitrogen atmosphere to form a copper conductors 6.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a ceramic thick film wiring circuit board, which improves the printing method for forming thick film circuits on the surface of a ceramic substrate using a dual firing system.

0002

2. Description of the Related Art Conventionally, a hybrid I is constructed by providing a thick film circuit on the surface of a ceramic substrate such as a ceramic substrate made of alumina or the like or a ceramic multilayer wiring board.
Various types of ceramic thick film wiring circuit boards for C are known. Among these, noble metal thick film systems that use precious metals such as silver, silver-palladium, and silver-platinum for thick film circuit wiring require the use of gold pads for bonding and ruthenium oxide resistors because they are fired in an oxidizing atmosphere. Although a high-precision resistor can be provided as a circuit, there is a problem that the high frequency characteristics and migration resistance of the conductor are poor. On the other hand, copper thick-film systems that use copper and sinter it in a nitrogen atmosphere for thick-film circuit wiring have excellent conductor properties and can obtain excellent signal propagation characteristics and high-frequency characteristics. The precision of the resistor was poor, and there was a problem in that it was not possible to provide a gold pad part fired in an oxidizing atmosphere.

[0003] In order to solve these problems, conventionally, MY
The DAS (DuPont Company: registered trademark) system is known. As shown in the flowchart of FIG. 4, this MYDAS system prepares a substrate made of, for example, alumina, prints a gold paste and, if necessary, a resistance-forming paste such as ruthenium oxide on the surface of the substrate, and then oxidizes it. It is fired in an atmosphere at a temperature of about 850° C. to form a gold pad portion and a resistor. Thereafter, a copper paste is printed and fired at a temperature of about 600° C. in a nitrogen atmosphere to form a circuit wiring portion. Thereby, it is possible to obtain a wiring board having a highly accurate resistor fired in an oxidizing atmosphere and a copper circuit wiring part fired in a nitrogen atmosphere and having excellent signal propagation characteristics and high frequency characteristics.

0004

[Problems to be Solved by the Invention] However, in the binary firing using the above-mentioned MYDAS system, a thick film circuit made of noble metal must be formed prior to the formation of a wiring circuit pattern made of copper. Since it is not possible to print thick film circuits using precious metals based on wiring circuit patterns, gold paste printing is used to form gold pads for wire bonding that need to be provided at the ends of copper wiring circuit patterns, for example. Sometimes, there was a problem in that it was not possible to print based on the wiring circuit pattern. As a result, the copper wiring of the thick film wiring pattern and the wiring of the gold pad portion are misaligned, resulting in a problem that a highly reliable connection cannot be made.

[0005] The purpose of the present invention is to solve the above-mentioned problems,
The present invention aims to provide a method for manufacturing a ceramic thick film wiring circuit board that can align two or more types of wiring patterns with high precision when forming a thick film circuit using a binary firing system. .

[0006]

[Means for Solving the Problems] The method for manufacturing a ceramic wiring board of the present invention is a dual firing process in which circuit wiring is formed on the surface of a ceramic substrate using a paste fired in an oxidizing atmosphere and a paste fired in a nitrogen atmosphere. In the method of manufacturing a ceramic thick film wiring board on which a thick film circuit is provided using a system, printing of the paste fired in the oxidizing atmosphere is based on at least two positioning through holes or via holes provided on the surface of the ceramic board. It is characterized by the fact that it is carried out in

[0007]

[Operation] In the above configuration, when forming a thick film circuit using a binary firing system, printing of patterns that need to be connected to copper wiring patterns such as noble metal wiring, especially gold pads, is performed on the thick film. Based on at least two positioning through holes or via holes provided on the outer periphery or inside the wiring circuit, for example, at least two positioning through holes or via holes provided separately for positioning or using ordinary electrical connection through holes or via holes. The precious metal paste is printed by aligning the through holes or via holes for positioning at various locations and using this pattern as a reference, so thick film circuits made of precious metal such as gold pads can be printed with high precision. This makes it possible to ensure the subsequent connection with the copper wiring pattern. Here, a through hole or a via hole in the present invention refers to a hole penetrating the front and back sides of a substrate, or a hole in which a conductor is embedded, or a hole provided in order to obtain conduction between layers in a printed lamination method or a green sheet lamination method. An opening with a conductor embedded in it.

[0008] In the present invention, the ceramic wiring board on which a thick film circuit is formed on the surface includes, for example, an alumina substrate that does not have an internal wiring layer, a ceramic multilayer wiring board that has an internal multilayer wiring layer, and shall include all of the applicant's co-fired ceramic multilayer wiring boards with oxidation-resistant vias.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a diagram for explaining an example of a through hole or via hole for positioning used in the method of manufacturing a ceramic thick film wiring circuit board of the present invention. In the example shown in FIG. 1, four thick film wiring circuits 1 having the same pattern are provided on the surface of a ceramic substrate 2. As shown in this embodiment, at least two through holes or via holes 3 used for making normal electrical connections are provided.
It can also be used as a reference when printing the noble metal paste, and at least two through holes or via holes 3 for positioning provided on the outer periphery of the four patterns can be used.
It can also be used as a reference when printing precious metal pastes. In this case, it goes without saying that it is necessary to separately add a pattern to the print mask to match the through hole or via hole for positioning the outer periphery. Furthermore, as shown in FIG. 2, since the through hole or via hole 3 is small, in order to achieve more accurate alignment, it is necessary to position the ring-shaped thick film pattern 4 provided around the through hole or via hole 3. It can also be used as a matching standard.

FIGS. 3A to 3C are diagrams showing each step of the method for manufacturing a ceramic thick film wiring circuit board of the present invention. In this example, first, as shown in FIG. 3(a),
A through hole or via hole 3 is provided at a predetermined position on the surface of the ceramic substrate 2 for electrical connection with a lower wiring layer or for positioning only. Next, in the binary firing system used in the present invention, it is necessary to first form a thick film circuit made of noble metal to be fired in an oxidizing atmosphere, so here, at least two or more through holes or via holes 3 are formed at the positions. As a reference, a pattern for forming a gold pattern is printed on the surface of the ceramic substrate 2 and then fired in an oxidizing atmosphere to provide a gold conductor 5 such as a gold pad portion as shown in FIG. 3(b). After that, resistors to be fired in an oxidizing atmosphere are printed a necessary number of times and then fired to form them.Finally, copper paste is printed in a predetermined position and fired in a nitrogen atmosphere, as shown in Figure 3(c). As shown, a copper conductor 6 is formed. In addition, when printing the final copper paste, in addition to using at least two through holes or via holes 3 as positioning standards as in the case of printing the noble metal paste described above, the previously formed gold pads etc. can be used as well as in the past. can also be used as a positioning reference to form copper conductors.

[0011] The present invention is not limited to the above-described embodiments, but can be modified and changed in many ways. For example, in the above embodiment, gold was used as an example of a noble metal thick film circuit, but other noble metals such as silver-palladium, silver-platinum, ruthenium oxide resistors, and insulating glass other than noble metals may also be used. Needless to say, the same effect can be obtained by using it. Further, in the above-described embodiment, an example was described in which four identical patterns are formed on one ceramic substrate, but it goes without saying that this number is not limited to four.

0012

Effects of the Invention As is clear from the above description, according to the present invention, when forming a thick film circuit using a binary firing system, noble metal wiring, especially copper wiring patterns such as gold pad portions, etc. Because the patterns that need to be connected are printed based on at least two positioning through holes or via holes provided on the outer periphery or inside the thick film wiring circuit, for example, thick film wiring made of noble metal such as gold pads can be printed. The film circuit can be printed with high precision, and the subsequent connection with the copper wiring pattern can be ensured.

[Brief explanation of drawings]

FIG. 1 is a diagram for explaining an example of a positioning through hole or via hole used in the method of manufacturing a ceramic thick film wiring circuit board of the present invention.

FIG. 2 is a diagram for explaining another example of a positioning through hole or via hole used in the present invention.

FIG. 3(a) is a diagram showing one step of the method for manufacturing a ceramic thick film wiring circuit board of the present invention. (b) is a diagram showing another step of the method for manufacturing a ceramic thick film wiring circuit board of the present invention. (v) is a diagram showing still another step of the method for manufacturing a ceramic thick film wiring circuit board of the present invention.

FIG. 4 is a flowchart showing an example of a conventional method for manufacturing a ceramic multilayer wiring board.

[Explanation of symbols]

1 Thick film wiring circuit 2 Ceramic substrate 3 Through hole or via hole 4 Thick film pattern 5 Gold conductor 6 Copper conductor

Claims (1)

[Claims] 1. A ceramic thick film wiring board in which a thick film circuit is formed on the surface of a ceramic substrate using a binary firing system in which circuit wiring is formed using a paste fired in an oxidizing atmosphere and a paste fired in a nitrogen atmosphere. In the method of manufacturing a ceramic thick film wiring circuit board, the printing of the paste to be fired in the oxidizing atmosphere is performed based on at least two positioning through holes or via holes provided on the surface of the ceramic substrate. Method.