JPS62120096A - Circuit substrate - 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] <Industrial Application Field> The present invention relates to a circuit board having a structure in which each terminal portion of a circuit pattern formed on an insulating base material is short-circuited with a jumper made of conductive paste. .

<Conventional technology> Conventionally, as the circuit density of circuit boards increases, electronic circuits are created by crossing a large number of narrow circuit patterns on an insulating base material while maintaining electrical insulation. The circuit pattern was formed. One of the commonly used techniques for insulating and intersecting different circuit patterns is a circuit board having a structure as shown in FIGS. 5 and 6. This circuit board has a circuit pattern 2.3 made of copper foil laminated with an adhesive on an insulating base material l, and a terminal portion 4, and a pair of circuit patterns 3 and 3 on both sides of the circuit pattern 2 are formed. A jumper 6 made of conductive paste is used to bridge the terminal parts 4 of the circuit pattern 3.
．． A conductivity between 3 and 3 was obtained. An insulating resist film 11 made of an insulating resist paint is formed between the jumper 6 and the circuit pattern 2 by a screen printing method in order to maintain insulation between them. It was widely used.

In addition, FIGS. 7 and 8 show other conventional examples,
It has a circuit pattern 2.3 and a terminal part 4 configured in the same manner as described above, and furthermore, in the center part of each terminal part 4, there is a part formed integrally with the insulating base material 1 with a diameter smaller than the outer diameter of the terminal part 4. A through hole 15 is bored through the hole. Then, the through holes 15 are filled with conductive paste, and conductive paste is applied between each through hole 15 via the surface of the insulating base material 1 opposite to the surface on which the circuit pattern 2.3 is formed. Shapa 6 was formed by applying the paste. Therefore, the jumper 6 is in close contact with the terminal portion 4 at the terminal portion large end surface 15a, and conductivity between the circuit patterns 3 and 3 is obtained.
Insulation was formed between the circuit patterns 2 via the insulating base material 1.

<Problems to be Solved by the Invention> However, in a circuit board having such a conventional configuration, for example, in the former configuration, the insulating resist film 11 formed by screen printing is affected by the screen of the printing plate. However, due to the inclusion of air bubbles during printing, it was difficult to form a good insulating film with a single layer, so multiple layers were overprinted to obtain the desired insulating properties. Therefore, the insulating resist film 1
1 formation requires drying for each layer, resulting in poor workability.Furthermore, after a long period of time, the conductive paste of the jumper 6 penetrates into the pinholes in the insulating resist film 11, resulting in poor insulation and poor reliability. There was a problem with missing parts.

In addition, in the latter configuration, when filling the conductive paste into the through hole 15, the conductive paste may protrude to the front side or burrs are formed when the through hole 15 is drilled, making it difficult to apply the conductive paste. Moreover, since the jumper 6 and the terminal part 4 are connected by the thin terminal part large end surface 15a, the connection strength of the jumper 6 is low. There was a problem that the reliability of the jumper connection was low.

<Objective of the Invention> The present invention has been made in view of the above-mentioned points.In a circuit board in which each terminal part of a circuit pattern is formed with conductive paste, a part of the circuit pattern that intersects with a jumper and maintains reliable insulation between the two, and
It is an object of the present invention to provide a circuit board with good workability in forming jumpers and with high reliability in jumper connections.

Means for Solving Problems〉 The circuit board of the present invention includes a predetermined circuit pattern made of a conductive metal formed on one surface of an insulating base material, and a circuit board provided on the circuit pattern to partially cover the circuit pattern. A circuit board having at least a pair of terminal portions interposed between the terminal portions and short-circuited to each other, and a jumper coated with a conductive paste and short-circuited between the terminal portions, the insulation having the circuit pattern formed thereon. From the side opposite to the surface of the base material, only the portions of the insulating base material corresponding to each terminal part are evaporated and removed by heating evaporation means to form recesses in which the conductive metal of each terminal part is exposed, and the jumper is Fill each recess with conductive paste, as well as each recess.

This structure is characterized in that it is formed by coating between layers, and this structure achieves the above object.

Function> This device is constructed as described above, and the end of the jumper filled in each recess is in close contact with the conductive metal of the terminal exposed in the recess, and is electrically connected. .

Then, between each concave part, the jumper passes through the surface of the insulating base material opposite to the surface on which the circuit pattern is formed, and electrical connection is made between each terminal part. An insulating base material is interposed between the two parts to maintain stable and high insulation properties.

<Embodiment> An embodiment of the present invention will be described below with reference to FIGS. 1 to 4.

FIG. 1 is a sectional view showing an embodiment of the circuit board of the present invention, and FIG. 2 is a plan view thereof. The insulating base material 1 is an insulating base material made of a polyester film in the embodiment, and a copper foil is laminated on the insulating base material l, and circuit patterns 2 and 3 and a circuit are formed on this by a known method such as etching. The circuit pattern 2 and the circuit pattern 3, in which a terminal portion 4 continuous to the pattern 3 is formed and constitute a circuit board, are electrically different circuit patterns, and the circuit pattern 3 extending on both sides of the circuit pattern 2 is , a terminal portion 4 is formed near the circuit pattern 2, and a pair of terminal portions 4 are provided so as to face each other. The insulating base material 1 below the center of each terminal part 4 is evaporated and removed by heating evaporation means to form a recess 5, and the bottom surface of the recess 5 has a recess 5. The conductive metal is exposed to form a conductive surface 4a.

Then, the conductive paste is filled into each of the four parts 5, and the conductive paste is applied between each of the recesses 5 via the surface of the insulating base material 1 opposite to the surface on which the circuit pattern 2゜3 is formed. The jumper 6 is formed by applying .

In the above, the conductive paste includes a binder,
A conductive metal such as silver powder is mixed into a solvent as a conductive filler, and by filling the conductive paste into the recess 5, the conductive surface 4a of the terminal portion 4 and the jumper 6 are brought into close contact. The pair of terminal portions 4 are electrically connected by a jumper 6.

Next, the formation of the recess 5 in the insulating base material 1 by the heating evaporation means described above will be explained.

The insulating base material l shown in FIG. 3A is made of a polyester film with a thickness of 11001 L, and has a circuit pattern. , terminal section 4
is a copper foil having a thickness of 15 μm and is adhered onto the insulating base material 1 using a polyester adhesive. Circuit pattern 2 of this insulating base material 1. From the side opposite to the surface on which the terminal part 4 is formed, a carbon dioxide laser with a wavelength of 10.6 gm, which is a heating evaporation means, is used to heat the insulating base material below the center of the terminal part 4 with an output of 35 W and a pulse width of 100 m5 eC. The pulsed beam is irradiated three times (indicated by self-arrows in FIG. 3B).

By this irradiation, the polyester film and the adhesive, which have an absorption rate of 80% at a wavelength of 10.6 gm, are melted and evaporated in the irradiated area and removed, thereby forming the recess 5. Also, wavelength 1
The copper foil, which has a reflectance of about 99% at 0.6 JLm, is not affected by melting or destruction due to the above-mentioned irradiation, and the conductive surface 4a on the lower surface of the terminal portion 4 is exposed (see FIG. 3C).

The recesses 5 thus formed are filled with conductive paste, and the recesses 5 are connected by jumpers 6 (
(See 3rd diagram).

In addition, as shown in FIG. 4 in detail, the part of the insulating base material 1 that is melted and removed at the laser beam irradiation part is the area around the recess 5 formed on the lower surface of the insulating base material 1 due to the influence of the melting heat.
Although a slightly gently raised heat-affected zone 7 is formed, this does not hinder the application and formation of the jumper 6.

In the above, the laser beam irradiation position is determined by controlling the laser beam position for each concave portion 5, or by using a mask made of a copper plate or the like with a large number of holes corresponding to the positions where a large number of concave portions 5 are formed. The plate is interposed on the insulating base material l, and the entire surface of the mask plate is scanned and irradiated with a laser beam,
The recesses 5 may be formed continuously.

Furthermore, the type of laser is not limited to carbon dioxide laser, but includes YAG laser, glass laser, etc.
Any heating evaporation means can be used as long as it forms a recess in the insulating base material by utilizing the difference in laser light absorption rate between the insulating base material of the circuit board and the conductive metal forming the circuit pattern.

<Effects of the Invention> As explained above, the circuit board of the present invention is a circuit board in which the jumper between each terminal portion of a circuit pattern is formed of a conductive paste, and the circuit board is a circuit board in which a jumper between each terminal portion of a circuit pattern is formed of a conductive paste. From the opposite side, only the portions of the insulating base material corresponding to each terminal portion are evaporated and removed by heating evaporation means to form recesses in which the conductive metal of each terminal portion is exposed, and the jumper is placed in each recess. Along with filling with conductive paste,
Since the coating is applied between each concave portion, high insulation is provided between the jumper and a part of the circuit pattern, and highly reliable insulation that is stable over time can be formed.

Furthermore, an insulating resist film is not required for jumper formation, and the conductive paste does not protrude to the front side of the insulating base material or cause problems such as difficulty in coating due to burrs, etc., making it easy to form jumpers. Complications are eliminated and jumpers can be formed with good workability.

Furthermore, since the jumper connection area is large, the jumper connection strength is large, and a circuit board with high jumper connection reliability is provided, which contributes to improving the reliability of equipment.

[Brief explanation of drawings]

1 is a cross-sectional view of the circuit board according to the embodiment of the present invention taken along line E-II in FIG. FIG. 4 is an enlarged sectional view of the recess. FIG. 5 is a sectional view showing an example of a conventional circuit board. FIG. 6 is a plan view, FIG. 7 is a sectional view showing another conventional circuit board, and FIG. 8 is a plan view. DESCRIPTION OF SYMBOLS 1... Insulating base material, 2.3... Circuit pattern, 4... Terminal part, 5... Recessed part, 6... Jumper. Patent application Brother Industries, Ltd. Patent attorney Ii 1) Akio; Nie ~ -11.
,・ ,1 :,! Lee =, 1 Figure 1 Figure 2 Figure 311OA 8th SC Figure 4

Claims (1)

[Scope of Claims] A predetermined circuit pattern made of a conductive metal formed on one surface of an insulating base material, and at least one circuit pattern provided on the circuit pattern and short-circuited to each other with a part of the circuit pattern interposed therebetween. A circuit board having: a pair of terminal portions; and a jumper coated with a conductive paste to short-circuit the respective terminal portions; evaporating and removing only the portions of the insulating base material corresponding to the above using heating evaporation means to form recesses in which the conductive metal of each terminal portion is exposed, and filling the jumper with a conductive paste in each recess. A circuit board characterized in that it is formed by coating between each recessed portion.