JPH0770799B2 - Circuit board - Google Patents

Description

The present invention relates to a circuit board used in electronic equipment.

2. Description of the Related Art Conventionally, the sixth circuit board has been used in various electronic devices.
There is one in the figure. In FIG. 6, 1 is an insulating substrate made of ceramic or the like having through holes 1a, 2 is a conductive layer formed by printing silver palladium or the like on the surface of the insulating substrate 1 and firing, and 3 is printing ruthenium oxide or the like. A resistance layer formed by post-baking,
Reference numeral 4 denotes an insulating layer which selectively forms on the conductive layer 2 and protects the conductive layer 2 and the resistance layer 3. Reference numeral 5 denotes a chip-shaped capacitor soldered to the electrode portion 2a of the conductive layer 2, a circuit component such as a transistor, 6 is a conductive layer 2 whose both ends are formed on the upper and lower surfaces of the substrate 1, respectively.
It is a conductive pin heat-welded with solder 7.

Problems to be Solved by the Invention According to the above configuration, the conductive layer 2 is printed by the thick film technique,
Since it is formed by baking, and the printing and baking are carried out at a high temperature of about 850 ° C., there is a problem that the conductive layer 2 is liable to be cracked in the processing process and lacks reliability. Further, the pins 6 are required to electrically connect the conductive layers 2 formed on both surfaces of the insulating substrate 1 to each other, and soldering work between the pins 6 and the conductive layers 2 is required. There is a problem that it causes an increase in work processes.

It is an object of the present invention to provide a circuit board that solves the above problems.

Means for Solving the Problems In the present invention, a resistance material is printed on an insulating substrate, fired to form a resistance layer, and a first conductive layer is formed by electroless plating or sputtering, and then electroplating is performed. A second layer on the first conductive layer
Forming a conductive layer, selectively removing the first and second conductive layers to form a wiring portion, and printing an insulating layer for protecting the wiring portion of the conductive layer and the resistance layer to form an electrode portion. Then, a circuit component connected to the electrode portion is attached on the electrode portion.

Function This structure simplifies the structure and work process, and improves high-density mounting.

Examples Next, examples of the circuit board according to the present invention will be described.
1 and 2 show a first embodiment of a circuit board according to the present invention. FIG. 1 is a sectional view of an essential part and FIG. 2 is a manufacturing process drawing.
1 and 11 are insulating substrates such as ceramics and glass provided with through holes 11a, 13 is a resistance layer which is formed by printing ruthenium oxide, carbon, etc. after printing and constitutes a resistance element,
Is a conductive layer formed of a conductive material such as copper on the surface of the insulating substrate 11 and on the inner wall of the through hole 11a, and 14 is selectively formed on the conductive layer 12 to protect the conductive layer 12 and the resistance layer 13 from each other. Layer, 15
Is a circuit component such as a chip-shaped capacitor and a transistor, which is heat-welded to the electrode portion 12a of the conductive layer 12 with solder 20.

Next, the manufacturing method will be described with reference to FIGS. 2 (A) to (F). First, as shown in FIG. 3A, an insulating substrate 11 made of ceramic or the like having a through hole 11a penetrating the upper and lower surfaces is prepared in advance. Next, a liquid resistance material mixed with ruthenium oxide is printed on the upper and lower surfaces of the insulating substrate 11 and baked to form a resistance layer.
Form 13. Next, as shown in FIG. 6C, copper is plated in an atmosphere of a temperature of about 50 ° C. to cover the surface of the insulating substrate 11, the inner wall of the through hole 11a and the upper surface of the resistance layer 13 with a conductive layer. Here, the thickness of the conductive layer 12 formed of copper is 20 to 100.
Although it is in the range of μm, since the insulating substrate is not electroplated, it is effective to first form a conductive layer of several μm by electroless plating or sputtering, and then electroplate to form a conductive layer having a predetermined thickness. Target.

Next, as shown in the diagram (D), the conductive layer 12 is etched to remove unnecessary portions, and the electrode portion 12a, the wiring portion 12b, and the wiring portion
A through hole electrode portion 12c is formed which is electrically connected to 12b. Next, as shown in FIG. 6E, an insulating layer 14 for protecting the conductive layer 12 and the resistance layer 139 except the electrode portion 12 is formed by printing and drying. Finally, as shown in FIG. 6F, a circuit component such as a chip-shaped capacitor or a transistor element is conductively fixed to the electrode portion 12a by heat welding the solder 21, and the circuit board is completed. FIG. 3 is a second circuit board according to the present invention.
It is an important section sectional view showing an example. In the figure, the same parts as those in FIG. 1 are designated by the same reference numerals, and the description thereof will be omitted. In Fig. 3,
11 is an insulating substrate, 12 is a conductive layer, 13 is a resistance layer that forms a resistance element, 16 is an adhesive, and 17 is a polyimide-based adhesive having excellent heat resistance and electrical insulation that is fixed to the insulating substrate 11 via the adhesive 16. Insulating film made of synthetic resin, 18 is insulating film 17
A second conductive layer that is fixed to and forms a wiring portion 18b and an electrode portion 18a with a conductive material such as copper or aluminum, 14 is an insulating layer that protects the upper surface of the conductive layer 18 except the electrode portion 18a, and 15 is a solder. 2
A circuit component such as a chip-shaped capacitor or a transistor element that is conductively fixed to the electrode portion 18a of the conductive layer 18 by heat welding of 1, and 22 electrically connects the electrode portion of the conductive layer 12 and the electrode portion of the conductive layer 18 by heat welding. It is a solder that conducts to. next,
The manufacturing method will be briefly described.

It is the first to form the resistance layer 13 and the conductive layer 12 on the insulating substrate 11.
This is similar to the case of the embodiment. Next, the insulating film 16 to which the conductive layer 18 coated with the adhesive 16 is fixed is attached to the insulating substrate 11. Next, the insulating layer 14 is formed by printing and then drying. Finally, the solder 22 is heat-welded to electrically connect the conductive layers 12 and 18, and the circuit portion 15 is soldered to complete the circuit board. In the case of this embodiment, an embodiment of a multilayer circuit board is shown.

FIG. 4 is a cross-sectional view of essential parts showing a third embodiment of the circuit board according to the present invention. In the figure, those parts which are the same as those corresponding parts in FIG. 1 are designated by the same reference numerals, and a life thereof will be omitted. In FIG. 4, through hole electrode portions 12c and 12d continuous with the wiring portions 12b and 12g are formed on the inner walls of the through holes 11a and 11b of the insulating substrate 11, and the through hole electrode portions 12c and 12d are formed on the insulating substrate 11 respectively. Is formed continuously with the electrode portions 12e and 12f on the lower surface of the. Reference numeral 30 is a circuit component having a lead terminal such as a coil, and the tip portion of the lead terminal is heat-welded to the electrode portions 12e and 12f by the solder 31.

Next, the manufacturing method will be briefly described. The process of fixing the resistive layer 13, the conductive layer 12, the insulating layer 14, and the chip-shaped circuit element to the electrode portion 12a of the conductive layer 12 on the upper surface of the insulating substrate 11 forms the resistive layer 13 only on the upper surface of the insulating substrate. Except for this, it is similar to the case of the first embodiment. Next, a circuit component having lead terminals
The circuit board is completed by inserting 30 into the through holes 11a and 11b, and heat-welding the tip portions of the lead terminals to the electrode portions 12e and 12f by soldering.

This embodiment is effective when the circuit components are arranged only on the upper surface of the insulating substrate 11.

FIG. 5 is a cross-sectional view of essential parts showing a fourth embodiment of the circuit board according to the present invention. In the figure, those parts which are the same as those corresponding parts in FIG. 4 are designated by the same reference numerals, and a description thereof will be omitted. In FIG. 5, reference numeral 32 denotes a circuit component having a lead terminal such as a coil, and the tip portion of the lead terminal is heat-welded to the wiring portions 12b and 12g of the conductive layer 12 by the solder 33. Next, the manufacturing method will be briefly described. The process of the resistive layer 13, the conductive layer 12, the insulating layer 14 and the chip-shaped circuit element 15 on the upper surface of the insulating substrate 11 and the electrode portion 12a of the conductive layer 12 is the same as in the third embodiment. Next, the lead terminals of the circuit component 32 are passed from the lower surface of the insulating substrate 11 to the through holes 11a and 11b, and the tip portions of the lead terminals are solder-dipped and the solder 21
At the same time, solder 33 is formed. With the above, the circuit board of this embodiment is completed.

In this embodiment, since the chip-shaped circuit component 15 mounted on the insulating substrate 11 and the circuit portion 32 having the lead terminal are simultaneously soldered to the wiring portion 12 (12a, 12b, 12g) of the conductive layer 12 by dipping, workability is improved. Is effective in terms of.

In the above description, the material of the conductive layer formed on the insulating substrate plate 11 is described as copper, but the conductive material is not necessarily limited to copper and may be another conductive material. As described above, a means of sputtering vapor deposition may be used, or a conductive paste mixed with copper or the like may be printed and dried to form the conductive paste. In addition, a plurality of through holes 11a and 11b are usually provided in the insulating substrate 11, but the same applies to other through holes.

EFFECTS OF THE INVENTION As described above, the printing and baking means has been used to form the conductive layer in the related art. However, since the rotating substrate according to the present invention can be formed by plating, it can be processed at a low temperature without baking, and the through-hole electrode can be used. Since the formation can be performed simultaneously with the formation of the conductive layer, the number of parts and the number of working steps can be reduced, and advantages such as suitability for high-density mounting are produced.

[Brief description of drawings]

1 and 2 show a first embodiment of a circuit board according to the present invention, respectively, and a sectional view of a main part, a manufacturing process drawing, and FIG. 3 show a second embodiment of the circuit board according to the present invention. 4 is a partial sectional view, FIG. 4 is a partial sectional view showing a third embodiment of the circuit board according to the present invention,
FIG. 5 is a cross-sectional view of an essential part showing a fourth embodiment of the circuit board according to the present invention, and FIG. 6 is a cross-sectional view of the essential part of a conventional circuit board. 1,11 …… Insulation board, 1a, 11a, 11b …… Through hole, 2,12…
… Conductive layer, 3,13 …… Resistive layer, 4, 14 …… Insulating layer, 5, 15, 30, 32
...... Circuit parts, 6 ...... pins, 16 …… adhesive, 17 …… insulating film, 2a, 12a, 12e, 12f …… electrode part, 12c, 12d …… through hole electrode part, 12b, 12g …… wiring Department

Claims (1)

[Claims] 1. A resistance material is printed on an insulating substrate and fired to form a resistance layer, a first conductive layer is formed by electroless plating or sputtering, and electroplating is performed on the first conductive layer. A second conductive layer is formed on the conductive layer, the first and second conductive layers are selectively removed to form a wiring portion, and an insulating layer for protecting the wiring portion of the conductive layer and the resistance layer is printed to form an electrode. A circuit board, wherein a portion is formed, and a circuit component connected to the electrode portion is attached on the electrode portion.