JPS61164299A - Thick film multilayer ceramic wiring board and manufacture thereof - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a ceramic wiring board, particularly a thick film multilayer ceramic wiring board for electronic circuits, and a method for manufacturing the same.

(Prior Art and its Problems) The conductor paste conventionally used as a conductor for thick-film multilayer ceramic wiring boards is mainly a mixture of Ag--Pd powder and glass powder. This Ag-Pd conductor paste is printed with a desired pattern on a ceramic substrate by screen printing method, dried, and then exposed to 800 to 850
It is baked for 10 minutes at a temperature of 0°C. However, this Ag-Pd conductor paste has a relatively high conduction resistance of 650 mΩ.

The use of Ag has drawbacks such as being prone to short circuits between conductors due to shimigration and being expensive. In contrast, recently, a Cu conductor paste fired in a neutral atmosphere has begun to be used. Cu conductor paste forms wiring patterns using the same process as Ag-Pd conductor paste, but Cu conductor has a conduction resistance of 6 compared to Ag-Pd conductor.
It is as low as 6 mΩ, has little -i migration and has good solder wettability. However, since Cu has a fast oxidation rate, there are some problems in storing the product against oxidation, such as an oxide film appearing on the conductor surface if it is left in the air for a while after firing.

(Objective of the Invention) An object of the present invention is to provide a thick film multilayer wiring board and a method for manufacturing the same, which are free from the above-mentioned drawbacks.

(Means for Solving the Problem) As a result of various studies on the above-mentioned drawbacks, the present inventors applied a Cu conductor paste on a ceramic substrate, baked it to form an inner conductor layer, and then formed an inner conductor layer. By applying an insulating paste on the top surface and baking it to form an insulating layer, and then applying an Ag-Pd conductor paste on the top surface of the insulating layer and baking it, a thick film multilayer ceramic wiring board without the above defects was created. It has been confirmed that it can be manufactured.

The present invention involves forming a layer of Cu conductor on the internal conductor layer and a layer of Ag-Pd conductor on the surface exposed groove layer, and applying and baking a Cu conductor paste on the thick film multilayer ceramic wiring board and ceramic substrate. The present invention relates to a method of manufacturing a thick film multilayer ceramic wiring board, which includes a step of forming an internal conductor layer and a step of applying an A, g-Pd conductor paste on the upper surface of an insulating layer and baking it to form a surface exposed conductor layer.

In the present invention, the Cu conductor paste forming the internal conductor layer is a Cu conductor paste baked in a neutral atmosphere, such as a normal glass bond type, )y:syl pold type, or a mixed bond type.
A conductive paste is used, and the Ag--Pd conductive paste forming the exposed conductor layer is preferably a paste for low-temperature firing (650° C. or lower), which is normally used for hollow substrates. As the insulating paste, a commercially available glass paste for overcoating is usually used.

The baking temperature of each paste is 850-1050°C when Cu conductor paste is used, 850-1050°C when insulating paste is used, and 500-650°C when A-g-Pd conductor paste is used. Preferably, the firing is carried out at a temperature in the range of .

There are no particular restrictions on the method of applying each paste, but it is preferable to apply it by screen printing.

(Example) Embodiments of the present invention will be described below with reference to the drawings.

(a), (1)) and (C) of FIG. 1 are top views showing the manufacturing process of a thick film multilayer ceramic wiring board according to an embodiment of the present invention; mm
.

It is a ceramic substrate with dimensions of 20 x 40 mm, and a chemical bond type Cu plate is placed on the top surface in the shape shown in Fig. 1 (a).
A conductor paste (manufactured by DuPont, trade name 4425) was applied by a screen printing method, and baked at a temperature of 1025° C. for 10 minutes in an N2 atmosphere to form the inner conductor layer 2.

Next, as shown in Fig. 1(b),
The insulating layer 3 and the through holes 4 were formed by baking at a temperature of 900° C. for 10 minutes in a N2 atmosphere. Furthermore, as shown in FIG. 1(C), Ag-Pd conductive paste (Sumitomo Metal Mining KK*, trade name C-4260) is applied on the upper surface of the insulating layer 3 to the portion that will become the electrode terminal and to the through hole 4 by screen printing. Apply.

A thick film multilayer ceramic wiring board was obtained by baking in the air at a temperature of 650° C. for 10 minutes to form a surface-exposed conductor layer 5.

Example 2 A glass bond type Cu conductor paste (manufactured by DuPont, trade name 9922) was used as the Cu conductor paste, and baked at 900°C, and a glass paste (manufactured by DuPont, trade name 4375) was used as the overcoat glass paste. death,
A thick film multilayer was formed using the same method and the same pattern as in Example 1, except that baking was performed at 875°C, Ag-Pd paste (manufactured by Thermalloy, trade name 4800) was used, and baking was performed at 600°C. A ceramic wiring board was obtained.

Next, when the conduction resistance of the thick film multilayer ceramic wiring boards obtained in Examples 1 and 2 was measured, it was found to be 70 mΩ, which is close to the conduction resistance of a single Cu conductor of the same pattern, 66 mΩ. Further, the thick film multilayer ceramic wiring boards obtained in Example 1 and Example 2 were placed in the atmosphere at a temperature of 60°C and a humidity of 90% R.
When left under the conditions of h, no change in conduction resistance due to oxidative deterioration of the Cu conductor in the internal conductor layer was observed.

(Effects of the Invention) 6. According to the present invention, the conduction resistance is as small as about 1/10 of that of a conventional thick-film multilayer ceramic wiring board made of a single Ag-Pd conductor, and there is little short circuit between conductors due to migration. A thick film multilayer ceramic wiring board with excellent oxidation resistance can be obtained.

[Brief explanation of the drawing]

(a), (1)) and (C1) in FIG. 1 are top views showing the manufacturing process of a thick film multilayer ceramic wiring board according to an embodiment of the present invention.・Inner conductor layer 3・
...Insulating layer 4...Through hole 5...
・Surface exposed conductor layer 1st opening (C)

Claims (1)

[Claims] 1. A Cu conductor layer is used as the inner conductor layer and A layer is used as the surface exposed conductor layer.
A thick film multilayer ceramic wiring board formed by forming a layer of g-Pd conductor. 2. A process of applying Cu conductor paste on the ceramic substrate and baking it to form an internal conductor layer, a process of applying an insulating paste on the top surface and baking it to form an insulating layer, and a process of applying Ag-Pd conductor paste on the top surface of the insulating layer. 1. A method for manufacturing a thick film multilayer ceramic wiring board, comprising the steps of coating and baking to form a surface exposed conductor layer.