WO2020166555A1

WO2020166555A1 - Wiring structure and method for producing wiring structure

Info

Publication number: WO2020166555A1
Application number: PCT/JP2020/005119
Authority: WO
Inventors: 亮介三井; 隼也佐藤; 敦史田中
Original assignee: 日本航空電子工業株式会社
Priority date: 2019-02-13
Filing date: 2020-02-10
Publication date: 2020-08-20
Also published as: JP2020136303A

Abstract

A wiring structure 100 comprises a first layer structure 40 and a second layer structure 60. The first layer structure 40 includes a first base portion 41, a first adhesive agent layer 42, and a linear first conductor 55. The second layer structure 60 includes a second base portion 61, a second adhesive agent layer 62, and a linear second conductor 71. At least a part of a surface of the first adhesive agent layer 42 in which the first conductor 55 is not formed and at least a part of a surface of the second adhesive agent layer 62 in which the second conductor 71 is not formed are adhered to each other. The first conductor 55 and the second conductor 71 are overlapped with each other. A wire included in the wiring structure 100 includes a linear conductor portion 80. At least a part of the conductor portion 80 comprises a conductor formed by the overlap of the first conductor 55 and the second conductor 71.

Description

Wiring structure and method of producing wiring structure

The present invention relates to a wiring structure and a method for producing the wiring structure.

1A, 1B, and 1C show the wiring structure disclosed in Patent Document 1. The wiring structure 10 has a configuration in which a microphone 20 is mounted.

In the wiring structure 10, an insulating pressure-sensitive adhesive layer 12 is formed on one surface 11 a of the film 11, and wiring (referred to as a conductor pattern in Patent Document 1) 13 is formed on the pressure-sensitive adhesive layer 12. It has a structure. The adhesive layer 12 is formed on the entire one surface 11 a of the film 11. The wiring 13 is formed by printing using silver ink (silver paste), and includes four conductors in this example.

Lands

13a and 13b are formed at one end and the other end of each conductor.

The microphone 20 is mounted on the wiring structure 10 by being pressed against the adhesive layer 12. The terminal 21 of the microphone 20 is in contact with the land 13 a of the wiring 13. A portion of the bottom surface 20a of the microphone 20 where the terminal 21 is not formed is mechanically coupled to the adhesive layer 12 by adhesion. 1A, 1B and 1C, reference numeral 30 indicates a cover film, reference numeral 31 indicates a window formed in the cover film 30, and reference numeral 32 indicates a notch formed in the cover film 30.

Japanese Patent No. 6293938

When the wiring is formed by the printing method using the conductive ink like the wiring structure 10 disclosed in Patent Document 1, the wiring resistance is increased as compared with the method of forming the wiring by copper foil or plating.

For example, when wiring is formed using screen printing, the volume resistivity of the cured conductive ink is generally about 100 times that of bulk metal. In this respect, when the wiring is formed using a printing method such as inkjet printing, gravure printing, flexographic printing or gravure offset printing, the volume resistivity of the cured conductive ink is about the same as that of bulk metal. However, according to these methods, since the wiring thickness is about several μm, that is, it is difficult to increase the film thickness, it is also difficult to reduce the wiring resistance.

An object of the present invention is to provide a wiring structure having a low wiring resistance and a method for producing the wiring structure.

The technical matters described here are not for the purpose of explicitly or implicitly limiting the invention described in the scope of the claims, and also for the benefit of the present invention (for example, the applicant and the right holder). It is not a statement of the possibility of admitting such limitation by anyone of the above, and is merely provided for the purpose of facilitating the understanding of the gist of the present invention. The outline of the present invention from other points of view can be understood, for example, from the claims as filed in this patent application.
At least a part of the wiring included in the wiring structure is formed by superimposing the first conductor formed on one base and the second conductor formed on the other base.

According to this invention, at least a part of the wiring is formed by superimposing the first conductor formed on the one base portion and the second conductor formed on the other base portion, that is, the thickness of the portion is reduced. Since it becomes large, the wiring resistance can be made small.

It is a top view of the prior art example of a wiring structure. It is a front view of the conventional example of a wiring structure. It is a partial expanded sectional view of the prior art example of a wiring structure. It is a wiring structure of an embodiment. (A) It is a front view. (B) A sectional view taken along the line CC. It is the first layer structure. (A) It is a top view. (B) It is a sectional view taken along the line DD. It is the second layer structure. (A) It is a top view. (B) EE line sectional drawing. FIG. 6 is a plan view of a wiring structure in which unnecessary parts are removed and components are mounted. FIG. 5B is an enlarged sectional view taken along line FF of the structure shown in FIG. 5A. It is a flowchart of a production process.

Embodiments of the present invention will be described with reference to the drawings. Hereinafter, the term “wiring” means an object, not an act, unless otherwise specified or unless clearly understood from the context.

FIG. 2 shows the wiring structure 100 of the embodiment. FIG. 2 shows the wiring structure 100 in a state before the unnecessary portion is finally removed by cutting.

The wiring structure 100 has a structure in which the first layer structure 40 and the second layer structure 60 are bonded to each other. FIG. 3 shows details of the first layer structure 40, and FIG. 4 shows details of the second layer structure 60. The configurations of the first layer structure 40 and the second layer structure 60 will be described with reference to FIGS.

The first layer structure 40 is formed on a rectangular plate-shaped first base portion 41, an insulating first adhesive layer 42 formed on the first base portion 41, and a first adhesive layer 42. The first wiring 50 and the alignment marker 56 formed on the first adhesive layer 42 are included. The first pressure-sensitive adhesive layer 42 is elastically deformable. The first adhesive layer 42 is formed on the entire one surface of the first base 41.

In this example, four electronic components such as chip components are mounted on the first wiring 50. Portions of the first wiring 50 located at both ends of the first base 41 in the long side direction (that is, the horizontal direction in the drawing) are connected to an external circuit (for example, a power supply circuit) other than the wiring structure 100. It is a connection part for doing.

The first wiring 50 includes ten lands 51 located in the central portion of the first base 41, ten conductive wire portions 52, and a land 53 described later. The

lands

51 and 53 are connection portions for connecting to an external circuit (for example, an electronic component) other than the wiring structure 100. The ten lands 51 include five lands 51 on the right side and five lands 51 on the left side. The ten conducting wire portions 52 extend from the five lands 51 on the right side to the right side and reach the right end edge of the first base 41, and the five conducting lands 51 on the left side extend to the left side from the five lands 51 on the left side. It includes five conducting wire portions 52 extending to the left edge of the one base portion 41. One of the five conductors 52 extending to the left side has a break in one place in the middle, and the other one has a break in two places in the middle. Wide lands 53 are formed on both sides of the cut portion.

The part of each conductor part 52 located at the edge of the first base part 41 is the connecting part 54, and the remaining part is the linear part 55. The spacing between the linear portions 55 is not constant, and the spacing between the linear portions 55 near the edge of the first base portion 41 is smaller than the spacing between the linear portions 55 near the land 51 (fine pitch wiring).

The four alignment markers 56 are located at the four corners of the first layer structure 40. The alignment marker 56 has a shape combining a cross and a circle. The alignment marker 56 is formed on the first adhesive layer 42, that is, on the same layer as the layer on which the first wiring 50 is formed.

Next, the second layer structure 60 will be described. The second layer structure 60 includes a rectangular flat plate-shaped second base 61 having the same size as the first base 41, an insulating second adhesive layer 62 formed on the second base 61, and a second base 61. The second wiring 71 is formed on the second adhesive layer 62, and the alignment marker 72 is formed on the second adhesive layer 62. The second adhesive layer 62 is elastically deformable.

One large square hole 63, three small rectangular holes 64, and two notches 65 are formed in the second base 61. The second pressure-sensitive adhesive layer 62 is formed on the entire one surface of the second base portion 61 having such a shape. The second wiring 71 includes a plurality of conducting wires and has a shape that is mirror-symmetrical to the linear portion 55 of the first layer structure 40, that is, in this example, the linear portion 55 of the first layer structure 40 is vertically inverted. There is. The four alignment markers 72 are located at four corners of the second layer structure 60. The alignment marker 72 has a shape imitating a cross outline. The alignment marker 72 is formed on the second adhesive layer 62, that is, in the same layer as the layer on which the second wiring 71 is formed.

The first wiring 50, the second wiring 71, and the

alignment markers

56 and 72 are formed by, for example, gravure offset printing using a conductive ink containing conductive particles such as silver particles or copper particles. The first wiring 50, the second wiring 71, and the

alignment markers

56 and 72 are cured products of conductive ink.

The first layer structure 40 and the second layer structure 60 are in a state where the surface on which the first wiring 50 is formed and the surface on which the second wiring 71 is formed face each other, that is, the first adhesive layer 42 and the second adhesive layer 42. With the pressure-sensitive adhesive layers 62 facing each other, the first layer structure 40 and the second layer structure 60 are pressed against each other to be bonded to each other.

Alignment between the first layer structure 40 and the second layer structure 60 is performed using

alignment markers

56 and 72 in this example. The first base portion 41 and the second base portion 61 formed of a film base material are transparent bodies in this example, and the first pressure-sensitive adhesive layer 42 and the second pressure-sensitive adhesive layer 62 are also transparent bodies in this example. Therefore, the alignment marker 56 and the alignment marker 72 can be recognized through the transparent first base portion 41 and the first adhesive layer 42 or through the transparent second base portion 61 and the second adhesive layer 62, that is, the alignment marker 56. , 72, the shape information (or position information) of the second layer structure 60 is positioned with respect to the first layer structure 40 by aligning the alignment marker 56 and the alignment marker 72 with each other. The first base 41 and the first pressure-sensitive adhesive layer 42 may be transparent and the second base 61 and the second pressure-sensitive adhesive layer 62 may be opaque, or the first base 41 and the first pressure-sensitive adhesive layer may be used. 42 may be an opaque body, and the second base portion 61 and the second adhesive layer 62 may be transparent bodies. It is not essential to use the

alignment markers

56 and 72, and the alignment may be performed using the shape information (or position information) of the linear portion 55 and the shape information (or position information) of the second wiring 71, for example. ..

The surface of the first adhesive layer 42 on which the first wiring 50 is not formed and the surface of the second adhesive layer 62 on which the second wiring 71 is not formed adhere to each other, whereby the first layer structure 40 is formed. And the second layer structure 60 are mechanically coupled to each other.

In a state where the first layer structure 40 and the second layer structure 60 are adhered to each other, ten lands 51 of the first layer structure 40 are exposed from the holes 63, and three lands 53 of the first layer structure 40 are exposed. It is exposed from the holes 64, and the connection portion 54 of the first layer structure 40 is exposed from the two notches 65.

The second wiring 71 corresponding to the above-mentioned second conductor is in close contact with the linear portion 55 corresponding to the above-mentioned first conductor in the state where the first layer structure 40 and the second layer structure 60 are bonded to each other. The linear portion 55 and the second wiring 71 which are overlapped with each other form a conductor portion 80 as if it were an integral body.

The first pressure-sensitive adhesive layer 42 and the second pressure-sensitive adhesive layer 62 are elastically deformed by pressing when they are bonded to each other. Since the elastic restoring force acts as a force in the direction in which the linear portion 55 and the second wiring 71 are pressed against each other, a good contact state between the linear portion 55 and the second wiring 71, that is, electrical coupling is obtained. In FIG. 2A, in order to clearly show the positional relationship between the first layer structure 40 and the second layer structure 60, the first wiring 50 and the alignment marker 56 are shown only by the outline.

In this example, the material of each of the first base portion 41 and the second base portion 61 is a flexible film substrate such as PET (polyethylene terephthalate), PEN (polyethylene naphthalate), and PI (polyimide). Alternatively, it may be a rigid base material.

The pressure-sensitive adhesive forming the first pressure-sensitive adhesive layer 42 and the second pressure-sensitive adhesive layer 62 is, for example, polyester-based, polyurethane-based, acrylic-based, epoxy-based, phenol-based, silicone-based, polyolefin-based, polyimide-based, vinyl-based, It is one or more types of polymers selected from natural high molecular weight polymers.

In order to improve tackiness, that is, mechanical properties, for example, polyester-based, polyurethane-based, acrylic-based, epoxy-based, phenol-based, silicone-based, polyolefin-based, polyimide-based, vinyl-based monomers or oligomers are mixed with the above-mentioned polymer. May be.

The wiring structure 100 is cut and processed along the alternate long and two short dashes line a shown in FIG. As a result, a finished product (see FIG. 5A) from which unnecessary parts are removed is obtained. The removal of the unnecessary portion is not an essential process, and the wiring structure 100 shown in FIG. 2A may be a completed product.

FIG. 5A shows a state in which

chip components

91, 92, 93, and 94 are mounted on the wiring structure 100 of the finished product. The chip 91 is arranged in the hole 63, and the chip 91 is mounted on the land 51 exposed in the hole 63. Three

chips

92, 93, 94 are arranged in the three holes 64, and the

chips

92, 93, 94 are mounted on the land 53 exposed in the holes 64. The chip 91 is, for example, a microcomputer, and the

chips

92, 93 and 94 are electronic parts such as resistors and capacitors. The

chips

91, 92, 93, 94 adhere to the first adhesive layer 42 by being pressed against the first adhesive layer 42. That is, the mounting of the

chips

91, 92, 93, 94 does not require soldering or heat treatment.

The connection portion 54 is exposed from the cutouts 65 of the second layer structure 60 at both ends in the left-right direction of the wiring structure 100, and an external circuit is electrically and mechanically connected to the connection portion 54 by the adhesion of the first adhesive layer 42. Connected to.

As is apparent from the embodiment, except for the connection portion for connecting to an external circuit, a part of the wiring included in the wiring structure, that is, the conductor portion 80, is the same as the first conductor of the first layer structure, that is, the linear portion 55. It is formed by overlapping the second conductor of the second layer structure, that is, the second wiring 71. Therefore, since the thick conductor portion 80 is formed by the overlapping of the two conductors, the resistance of the conductor portion 80 becomes small. To describe from another viewpoint, the wiring included in the wiring structure 100 includes the linear conductor portion 80, and at least a part of the conductor portion 80 (the whole conductor portion 80 in the embodiment) is included in the first layer structure 40. It is a conductor formed by stacking the first conductor 55 and the second conductor 71 of the second layer structure 60. In the embodiment, the wiring included in the wiring structure 100 does not include the land 51, the land 53, and the connection portion 54.

As is clear from the embodiment, the conductor portion having a large thickness (that is, at least one of the wirings of the wiring structure is formed by superimposing the first conductor formed on one substrate and the second conductor formed on the other substrate). Part) is formed. Therefore, the wiring structure of the embodiment is useful when the conductor on the substrate is formed by a printing method in which it is difficult to form a thick conductor. Alternatively, the wiring structure of the embodiment is also useful in the case of fine-pitch wiring in which a plurality of thin conductive wires are arranged at narrow intervals (for example, the interval between two adjacent conductive wires is 0.3 mm or less). Furthermore, the wiring structure of the embodiment is useful even when the width of the conductive wire is narrow (for example, the width of the conductive wire is 0.3 mm or less).

As is clear from the embodiment, at least a part of the wiring included in the wiring structure is formed by superimposing the first conductor formed on one substrate and the second conductor formed on the other substrate. Therefore, for example, even if one conductor has a poor conductivity, the wiring structure functions properly unless the other conductor has a poor conductivity. In this respect, the wiring structure of the embodiment achieves a good yield.

The wiring structure of the embodiment has a vertically symmetrical structure as shown in the cross-sectional view of FIG. 5B. The second adhesive layer 62 and the second base portion 61 are located above the conductor portion 80, and the first adhesive layer 42 and the first base portion 41 are located below the conductor portion 80. The conductor portion 80 is sandwiched between the adhesive layer and the base portion, and is located at the center of the cross section of the wiring structure. Therefore, even if the narrow-width extension 101 (see FIG. 5A) of the wiring structure 100 is, for example, a cable, and the bending is applied in the extension direction of the conductor portion 80 and the direction orthogonal to the width direction of the narrow-width extension 101, the conductor No compressive stress or tensile stress is strongly applied to the portion 80. Therefore, peeling of the adhesive layer is unlikely to occur, and a cable portion that is resistant to bending can be realized.

The second wiring 71 does not have to have a shape that completely matches the shape of the linear portion 55, and a part of the second wiring 71 does not have to overlap the linear portion 55. The line width of the part or the whole may be different from the line width of the linear part 55.

In the embodiment, a part of the surface of the first adhesive layer 42 on which the first wiring 50 is not formed is used for adhering the

chips

91, 92, 93, 94. Therefore, the mechanical coupling between the first layer structure 40 and the second layer structure 60 is performed by at least a part of the surface of the first adhesive layer 42 where the first wiring 50 is not formed and the second adhesive layer 62 of the first adhesive layer 62. This is achieved by adhering at least some of the surfaces on which the two wirings 71 are not formed to each other.

The method for producing the wiring structure 100 is clear from the above description, but the process will be described again.

First, the first layer structure 40 including the first base portion 41, the first adhesive layer 42, and the linear first conductor 55 is manufactured (step S1). Next, the second layer structure 60 including the second base portion 61, the second adhesive layer 62, and the linear second conductor 71 is manufactured (step S2). However, step S1 may be executed after step S2 instead of this order. Further, at least a part of the surface of the first adhesive layer 42 on which the first conductor 55 is not formed and at least a part of the surface of the second adhesive layer 62 on which the second conductor 71 is not formed are adhered to each other. Then, the wiring structure 100 is obtained by overlapping the first conductor 55 and the second conductor 71 with each other (step S3).

The first base 41 and the first pressure-sensitive adhesive layer 42 are transparent bodies, or the second base 61 and the second pressure-sensitive adhesive layer 62 are transparent bodies, or the first base 41, the first pressure-sensitive adhesive layer 42, When the second base portion 61 and the second pressure-sensitive adhesive layer 62 are transparent bodies, the process of step S3 includes the shape information obtained through the transparent bodies (that is, the shape information of each of the

alignment markers

56 and 72 in the embodiment). The process may be utilized to perform alignment of the first layer structure 40 and the second layer structure 60.

The term “connected” and any inflections thereof mean a direct or indirect connection between two or more elements. There may be one or more intermediate elements between two elements that are "connected" to each other.

Unless otherwise specified, an ordinal number (for example, “No. ○” in which the prefix “No.” is combined with a Chinese number or an arithmetic digit) is an element that is modified by the ordinal number or combined with the ordinal number in the order of the elements or It is not intended to be limited by the amount of the element. The use of ordinal numbers is simply used as a convenient method of distinguishing two or more elements from each other, unless otherwise stated. Therefore, for example, the phrase “first X” and the phrase “second X” are expressions for distinguishing two Xs, and do not necessarily mean that the total number of Xs is 2, or the first X is the first. It does not necessarily mean that 2X must precede.

The term “include” and its inflection are used as non-exclusive expressions. For example, the sentence “X includes A and B” does not deny that X includes components other than A and B (eg, C). Further, when a sentence includes the term “comprise” or its inflection includes a phrase combined with a negation, the sentence only refers to the term “comprise” or the object of the inflection. Thus, for example, the sentence "X does not include A and B" acknowledges that X may include components other than A and B. Furthermore, the term "or" as used in the specification or claims is not intended to be an exclusive OR.

In the present disclosure, if translations add articles, such as a, an and the in English, the present disclosure may include that nouns following these articles are plural.

Although the embodiments of the present invention have been described above, the present invention is not limited to these embodiments. Various modifications and variations are allowed without departing from the scope of the present invention. The selected and described embodiments are intended to illustrate the principles of the invention and its practical application. The present invention is used in various embodiments with various modifications or variations, and the various modifications or variations are determined according to the intended use. All such modifications and variations are intended to be included within the scope of this invention as defined by the appended claims and, when interpreted in a fair, lawful and fairly imparted breadth, the same. Protection is intended to be given.

10 Wiring Structure 11 Film 11a One Surface 12 Adhesive Layer 13 Wiring 13a Land 13b Land 20 Microphone 20a Bottom 21 Terminal 30 Cover Film 31 Window 32 Notch 40 First Layer Structure 41 First Base 42 First Adhesive Layer 50 First Wiring 51 land 52 conducting wire portion 53 land 54 connecting portion 55 linear portion 56 alignment marker 60 second layer structure 61 second base portion 62 second adhesive layer 63 hole 64 hole 65 notch 71 second wiring 72 alignment marker 80 conductor portion 91 Chip 92 Chip 93 Chip 94 Chip 100 Wiring structure 101 Narrow width extension

Claims

Wiring structure,
A first layer structure,
And a second layer structure,
The first layer structure is
A first base,
An insulating first adhesive layer formed on the first base portion, provided that the first adhesive layer is elastically deformable;
A linear first conductor formed on the first adhesive layer,
The second layer structure is
A second base,
An insulating second adhesive layer formed on the second base portion, provided that the second adhesive layer is elastically deformable;
A second linear conductor formed on the second adhesive layer,
At least a part of the surface of the first pressure-sensitive adhesive layer on which the first conductor is not formed and at least a part of the surface of the second pressure-sensitive adhesive layer on which the second conductor is not formed are adhered to each other. Cage,
The first conductor and the second conductor overlap each other,
The wiring included in the wiring structure includes a linear conductor portion,
At least a part of the conductor portion is a conductor formed by overlapping the first conductor and the second conductor.
The wiring structure according to claim 1,
The first conductor is a cured product of conductive ink,
The second conductor is a cured product of conductive ink.
In the wiring structure according to claim 1 or 2,
The conductor portion is a conductor included in the fine pitch wiring.
The wiring structure according to any one of claims 1 to 3,
The first base and the first pressure-sensitive adhesive layer are transparent bodies,
Or
The second base and the second pressure-sensitive adhesive layer are transparent bodies,
Or
The first base, the first pressure-sensitive adhesive layer, the second base and the second pressure-sensitive adhesive layer are transparent bodies.
The wiring structure according to any one of claims 1 to 4,
The wiring does not include a connecting portion for connecting to an external circuit.
A method of producing a wiring structure, comprising:
A first base,
An insulating first adhesive layer formed on the first base portion, provided that the first adhesive layer is elastically deformable;
Manufacturing a first layer structure including a linear first conductor formed on the first adhesive layer;
A second base,
An insulating second adhesive layer formed on the second base portion, provided that the second adhesive layer is elastically deformable;
Manufacturing a second layer structure including a linear second conductor formed on the second pressure-sensitive adhesive layer;
At least a part of the surface of the first pressure-sensitive adhesive layer on which the first conductor is not formed and at least a part of the surface of the second pressure-sensitive adhesive layer on which the second conductor is not formed are adhered to each other, And an assembling step of obtaining the wiring structure by overlapping the first conductor and the second conductor with each other.
The method of claim 6, wherein
The first base and the first pressure-sensitive adhesive layer are transparent bodies,
Or
The second base and the second pressure-sensitive adhesive layer are transparent bodies,
Or
The first base, the first adhesive layer, the second base and the second adhesive layer are transparent bodies,
The assembling step includes a process of performing alignment between the first layer structure and the second layer structure using shape information obtained through a transparent body.