JPH02148792A - Manufacture of printed wiring board - Google Patents

Abstract

PURPOSE:To improve electrical, mechanical strengths of conductive paste to a circuit terminal connected with conductive paste with insulating layer forming resin ink simultaneously upon formation of an insulating layer, and then covering it with conductive ink. CONSTITUTION:When other circuit 4 such as a jumper, etc. is formed on the terminal 1 of a printed circuit 10 formed on the upper side of an insulating board 20, the part of the circuit 10 except the terminal 1 of the circuit 10 is covered with an insulator coating layer to form the circuit 4, and a coating layer 2 covered with a plurality of bumps 2a in a multiple spot state is formed on the surface of the terminal 1 simultaneously upon formation of the insulator coating layer. Thereafter, the circuit 4 is printed with the conductive ink, and cured to connect a terminal 4a to the terminal 1. Thus, it can prevent the conductive paste from peeling at the jack to improve electrical, mechanical strengths.

Description

[Detailed Description of the Invention] The present invention relates to a method for manufacturing a printed wiring board, and particularly relates to a method for manufacturing a printed wiring board, in which other circuits such as jumper circuits are attached to connection lands of a printed wiring circuit formed on an insulating substrate. The present invention relates to a method of manufacturing a printed wiring board, in which a conductive ink such as a copper paste is applied to a part of the printed wiring board.

Conventional printed wiring boards are manufactured by forming the required printed wiring circuit by etching the copper foil of a so-called copper-clad laminate, which is a so-called copper-clad laminate in which copper foil is stretched over an insulating substrate. .

In addition, when forming a circuit such as a jumper circuit between the printed wiring circuits on such a printed wiring board, as shown in FIG. A manufacturing method has been developed and implemented in which the connected jumper circuit section 4 is formed by applying conductive ink made of copper paste or other conductive paste by means such as silk printing and curing it. Various conductive inks that are effective in forming this type of circuit have also been developed.

However, when forming a circuit by applying a conductive paste such as copper paste or by silk printing, a problem arises in the adhesion between the circuit terminal portion 1 of the copper foil on the printed wiring board and the conductive paste, that is, ink. .

In other words, the conductive paste contains carbon to improve conductivity.
Because a large amount of conductive substances such as copper particles are mixed into the resin ink, there is less resin that affects the adhesion to the copper foil terminal surface, and the adhesion to metal surfaces is lower than that of ordinary resin inks. This has serious drawbacks, such as not only the electrical connection force becoming unstable, but also the mechanical strength being weak and peeling due to thermal shock during soldering of parts.

Therefore, an object of the present invention is to provide a method for manufacturing a printed wiring board that can improve the electrical and mechanical strength of the conductive paste and the circuit terminal portion.

Ruta's method for manufacturing a printed wiring board of the present invention forms a printed wiring circuit on an insulating substrate, and
When forming a circuit part to be connected to the circuit by coating a part of the terminal with an insulating layer and then depositing a conductive ink such as copper paste, the terminal surface of the terminal part to be connected with the conductive ink. A part of the conductive ink is coated with an insulating layer forming resin ink at the same time as the insulating layer is formed, and then the conductive ink is applied.

According to the method for manufacturing a printed wiring board of the present invention, prior to circuit formation using conductive ink, a coating layer is formed using resin ink on a part of the terminal surface of the circuit terminal portion of the printed wiring circuit of the printed wiring board. By forming a circuit using the conductive ink after the formation, the coating layer of the resin ink formed on a part of the terminal surface can provide an adhesion effect due to its compatibility with the conductive ink, and the terminal surface It is possible to improve the electrical and mechanical strength of the contact portion between the conductive ink and the circuit portion.

Particularly, the workability is improved by carrying out the process of applying a resin ink coating layer to a part of the terminal surface at the same time as the process of forming the insulating coating layer.

An embodiment of the method for manufacturing a printed wiring board of the present invention will be described with reference to the drawings.

(First Example) Figures 1 and 2 show a first example of the method for manufacturing a printed wiring board of the present invention. Fig. 2a is an enlarged plan view showing a state in which a jumper circuit is connected to the terminal portion;
FIG. 2 is a sectional view taken along line A--A in FIG. 2a.

As shown in FIGS. 1 and 2, in the printed wiring board manufacturing method of the present invention, other circuits, such as jumper circuits, are connected to the terminal portions 1 of the printed wiring circuit 10 formed on the upper side of the insulating substrate 20. 4, as shown in FIG. 1, prior to forming the jumper circuit 4, resin ink, such as a conductive paste used for forming the jumper circuit 4, is applied to the surface of the terminal portion 1. Using a resin ink having the same composition as the resin ink except for the conductive material in the composition, a coating layer 2 having a plurality of protrusions 2a adhered in a multi-dot manner is formed by means such as printing.

After that, jumper circuit 4 is printed using conductive ink.
By printing and curing this, a jumper circuit 4 in which the terminal portion 4a is electrically connected to the terminal portion l can be formed.

Further, the jumper circuit 4 is protected by covering it with an insulating overcoat film 5.

Furthermore, when forming the jumper circuit 4 on the printed wiring board 21, an insulating coating (not shown) is applied to a portion that needs to be insulated from other printed wiring circuits 10 due to the relationship with the printed wiring circuit IO. However, in this embodiment, the other parts of the circuit 10 except for the terminal portion 1 of the printed wiring circuit 10 are coated with an insulating coating layer, and at the same time as the insulating coating layer is formed. The method is characterized in that a coating N2 is formed on the surface of the terminal portion 1 in which a plurality of protrusions 2a are adhered at multiple points.

Therefore, the insulating resin ink is usually applied at the same time as the formation of the insulating film to be applied to the upper side of the printed wiring circuit 10, which is performed prior to the formation of circuits such as the jumper circuit 4, that is, at the time of forming the insulating film. At the same time as silk printing, an increase in the number of steps can be prevented by printing a coating layer 2 that breaks the protrusions 2a on the terminal surface of the terminal portion 1 in multiple points. However, regarding the resin ink at this time, the protrusions 2a are naturally formed using the same resin ink as the insulating coating.

The coating layer 2 of the terminal portion 1 has a structure in which a plurality of protrusions 2a are attached to the terminal surface so that the terminal surface is partially covered and the other surface is exposed.

As is clear from the above examples, according to the method of manufacturing a printed wiring board according to this example, the printed wiring circuit lO
After the formation of the necessary jumper circuit 4, etc., the terminal surface of the terminal part l is formed using the characteristic that ordinary resin ink has excellent adhesion to both metal surfaces and conductive ink. A circuit such as a jumper circuit 4 is formed by applying a resin ink to a portion of the jumper circuit 4 and then applying a conductive ink.

(Second Embodiment) FIGS. 3 and 4 show a second embodiment of the method for manufacturing a printed wiring board of the present invention. FIG. 3 is an enlarged plan view of the terminal portion, and FIG. 4 a is an enlarged plan view of the terminal portion. FIG. 4 is an enlarged plan view of a state in which a jumper circuit is formed, and FIG. 4 is a sectional view taken along the line B--B of FIG. 4a.

The method for manufacturing a printed wiring board according to the second embodiment includes forming a mesh 3a-shaped coating layer 3 on the terminal surface of the terminal portion 1 of the printed wiring circuit 10, in place of the multi-point coating layer 2 of the first embodiment. It is formed by breaking resin ink using a method such as silk printing.

Thereafter, the jumper circuit 4 is formed by the same method as in the first embodiment.

Since the other manufacturing methods are completely the same as those in the first embodiment, the same components are given the same numbers and the explanation thereof will be omitted.

According to the pudding 1 of the present invention - the method for manufacturing a wiring board, resin ink is applied to the terminal surface of a printed wiring circuit in the form of a mesh or multi-dot shape, and then a conductive ink is applied thereon. By depositing and forming circuits such as jumper circuits using ink, it prevents peeling between the terminal surface and the conductive paste at the circuit connection part of jumper circuits, etc., and reliably prevents defects on printed wiring boards. can do.

[Brief explanation of the drawing]

Figures 1 and 2 show a first embodiment of the method for manufacturing a printed wiring board of the present invention, and Figure 1 shows a method in which a multi-dot coating layer is provided with resin ink on the terminal surface of a terminal portion in a printed wiring circuit. An enlarged plan view showing the state; FIG. 2a is an enlarged plan view showing the state in which a jumper circuit is connected to the terminal portion;
Figure 2 is a sectional view taken along the line A--A in Figure 2a, Figures 3 and 4 show a second embodiment of the method for manufacturing a printed wiring board of the present invention, and Figure 3 shows a cross-sectional view of the terminal section. An enlarged plan view, FIG. 4a is an enlarged plan view of a state in which a jumper circuit is formed in the terminal part,
FIG. 4 is a sectional view taken along the line B--B in FIG. 4a, and FIG. 5 is a partially enlarged view showing the connection between a conventional terminal surface and a jumper circuit using conductive ink. 1...Terminal portion 2.3...Coating layer made of resin ink 4...Jumper circuit 10 formed of conductive paste...Printed wiring circuit 20...Insulating substrate 2
1... Overcoat film patent applicant Nippon Neumk Co., Ltd. Fig. 20... Kyoei Katoki Fig. (b) -, -~]-20 No. 4 (a) Fig. -~D'.

Claims (2)

[Claims] 1. A printed wiring circuit is formed on an insulating substrate, and after coating at least a portion of this printed wiring circuit with an insulating layer, a conductive ink such as copper paste is applied to form a circuit portion connected to the circuit. In this case, a part of the terminal surface of the terminal portion to be connected with conductive ink is coated with an insulating layer forming resin ink at the same time as forming the insulating layer, and then the conductive ink is applied. A method for manufacturing printed wiring boards. 2. 2. The method of manufacturing a printed wiring board according to claim 1, wherein the terminal surface is covered with the insulating layer forming resin ink in a halftone dot shape or a grid shape.