JPH04139792A - Multilayer resin board - Google Patents

Abstract

PURPOSE:To reduce disconnection when a multilayer resin board is bent, by forming a conductive pattern positioned at a bending part, so as to have a wide pattern width. CONSTITUTION:Thermoplastic resin wherein a hole 12 is bored in an insulating film 11 of a film board 10 is used as binder, in which silver particles are contained to obtain conductive paste. By using said paste, a conductive pattern 13 is formed, and said paste is printed on the surface region containing the inner surface of the hole 12, thereby forming a through hole part 14. Desired conductive patterns 23, 33, and through hole parts 24, 34 are formed on other film boards 20, 30 formed by the same way as the board 10. The boards 10-30 are so stacked that the respective through hole parts 14, 24, 34 are made to coincide with one another, and subjected to thermo-compression bonding. The above multilayer resin board is bent angularly with a <-shaped hot press machine, thereby forming a multilayer resin board 40.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a multilayer resin substrate, and particularly to a multilayer resin substrate having a bent portion.

(Prior Art) Recently, as electronic devices have become smaller, lighter, and thinner, control circuit devices and the like used in these electronic devices have been required to be smaller, lighter, and thinner. Since this control circuit device has electronic components such as semiconductors mounted on a substrate having a conductive pattern, the control components such as semiconductors and the substrate must be made smaller to make them lighter, thinner, and smaller. There is a need.

Substrates used for this type of control circuit devices include glass-epoxy substrates, which are made by mixing resin such as epoxy with glass and metal plating with conductive patterns on the surface, polyester substrates, etc.
Flexible print (F P
C) Substrates are often used.

However, glass epoxy boards require a complicated plating process, and conventional FPC boards are single-layered, making it difficult to conduct high-density wiring.

In order to solve these problems, progress has been made in the development of high-density mounting multilayer resin substrates in which conductive patterns are formed on film-like resin substrates and a plurality of these substrates are stacked.

This multilayer resin substrate is manufactured, for example, by the following method.

First, through-holes are formed at appropriate locations on a heat-deformable film substrate made of thermoplastic resin such as polycarbonate, polysulfone, or polyarylate, and a conductive paste with a thickness of, for example, about 20 μm is screen printed on the surface to make it conductive. Form sexual patterns.

Then, multiple layers of these film substrates are stacked and bonded under heat.
Laminated integrally.

In such multilayer resin substrates, the conductive patterns are integrally bonded to the film substrate, eliminating the conventional plating process, etc., and multiple conductive patterns are mounted three-dimensionally, achieving high density. can.

(Problem to be Solved by the Invention) By the way, this multilayer resin substrate may be used as a flat plate, but depending on the structure of electronic equipment, etc., it may be necessary to bend it at a right angle or the like at a predetermined point before use. Sometimes.

The multilayer resin substrate bent in this way is formed by bending a multilayer resin substrate formed into a flat plate, so it is not only a heat deformable film but also a conductive pattern of conductive paste. can also be transformed.

In this case, in particular, the conductive pattern that intersects the bend is
When a large bending stress is applied, flags may occur in the conductive pattern in this part, or in the worst case, the conductive pattern may break, resulting in a lack of reliability as a product.

An object of the present invention is to obtain a multilayer resin substrate having the above-mentioned bent portion, which can reduce disconnection of the conductive pattern.

[Structure of the Invention (Means for Solving the Problems) The present invention consists of laminating a film substrate on which a conductive pattern is formed using a conductive paste using a thermoplastic resin as a binder, on an insulating film made of a thermoplastic resin. The multilayer resin substrate is integrated by thermocompression bonding, and the multilayer resin substrate is formed with a bent part, and the conductive pattern located at the bent part is formed with a wide pattern width. It is a resin substrate.

(Function) In the present invention, since the pattern width of the conductive pattern located at the bending part is formed wide, even if a crack occurs in the conductive pattern when this multilayer resin substrate is bent, a disconnection occurs. It can reduce the occurrence of

(Example) An example of the present invention will be described in detail below with reference to the drawings.

The structure and manufacturing method of the multilayer resin substrate according to the present invention shown in FIG. 1 will be explained.

same! ! As shown in I (A), first the film substrate lO
is a thermoplastic resin such as polycarbonate with a thickness of 50 mm.
After making holes 12 in the insulating film 11 with a diameter of approximately μm, a thermoplastic resin such as vinyl chloride-vinyl acetate copolymer is used as a binder, and 92 silver particles with an average particle size of 5 μm are added to the binder.
A desired conductive pattern 13 is formed by screen printing a conductive paste containing parts by weight, and the holes 1 described above are
Through-hole portions 14 are also formed on the surface area including the inner surface of 2 by printing conductive paste.

Further, a desired conductive pattern 23 is also formed on other film substrates 20 and 30 formed in the same manner as the film substrate 10.
．． 33, through-hole portions 24.34 are formed.

Film substrate 10.20.30 configured as above
are stacked so that the respective through-hole portions 14, 24, and 34 match, and are thermocompression bonded under conditions of, for example, a temperature of 160 to 180° C. and a pressure of 10 to 20 kg/a/.

At this time, the conductive paste printed on each through-hole part 14, 24, 34 is thermally deformed, and the interlayer connection of each film substrate 10, 20, 30 is made, and the insulating film is also thermally deformed. , a plurality of laminated film substrates are integrated.

Furthermore, in order to bend the integrated multilayer resin substrate in a predetermined position, for example, it is bent into a rectangular shape using a letter-shaped heat press (not shown), as shown in FIG. B
) A multilayer resin substrate 40 as shown in FIG.

Here, as shown in FIG. 2, the conductive pattern in this embodiment is formed so that the pattern width is wider at a portion located at a bent portion of the multilayer resin substrate 40 than at other portions.

This is because when a multilayer resin substrate is bent, stress due to deformation is usually applied around the bent portion, and therefore cracks are likely to occur in the conductive pattern in response to the distortion.
If the pattern width of the conductive pattern is wide as in this example, even if cracks occur due to deformation of the film substrate, problems such as electrical disconnection of the conductive pattern can be greatly reduced. .

Incidentally, since the conductive patterns located at locations other than the bent portions are formed thinner than the conductive patterns located at the bent portions, high-density wiring of the multilayer resin substrate is not obstructed.

In the above examples, polycarbonate is used as the insulating film, but examples include polyvinyl chloride, polystyrene, saturated polyester resin, polyethylene, polypropylene, polyphenylene oxide, polysulfone, polyphenylene sulfide, polyacetal, polyamide. It is also possible to select other thermoplastic resins such as.

Furthermore, as for the metal powder kneaded into the conductive paste, silver particles are used in the above embodiments, but metal particles of copper, nickel, gold, platinum, aluminum, etc. can also be used, for example. .

[Effects of the Invention] According to the present invention described above, since the pattern width of the conductive pattern located at the bent portion is formed wide, cracks in the conductive pattern due to bending of the multilayer resin substrate occur. Even if the cable is connected, the occurrence of electrical disconnection can be reduced.

[Brief explanation of the drawing]

FIGS. 1A and 1B are cross-sectional views showing a multilayer resin substrate according to an embodiment of the present invention, and FIG. 2 is a schematic diagram showing the shape of a conductive pattern in the above embodiment. 10.20.30...Film substrate 11.21
．． 31... Insulating film 12... Hole 13.23.33... Conductive pattern 14.2
4.34...Through hole part 40...
Multilayer resin substrate patent attorney Ono 1) Yoshihiro 1st figure Conductive pattern (B) 2nd figure

Claims (1)

[Claims] A multilayer resin substrate is a multilayer resin substrate in which a film substrate on which a conductive pattern is formed using a conductive paste using a thermoplastic resin as a binder is laminated on an insulating film made of a thermoplastic resin and integrated by thermocompression bonding, wherein the multilayer resin A multilayer resin substrate, characterized in that the substrate is formed with a bent portion, and the conductive pattern located at the bent portion is formed to have a wide pattern width.