JP2022115402A - wiring circuit board - Google Patents

Abstract

To provide a wiring circuit board suitable for having a bent part while suppressing breakage of wiring.SOLUTION: A wiring circuit board X1 comprises a first insulating layer 10, a first conductor layer 20, a second insulating layer 30, a second conductor layer 40, and a third insulating layer 50 in this order in a thickness direction T. The first conductor layer 20 includes a plurality of first extended wiring parts 21E. The first extended wiring parts 21E extend in a first direction D1 orthogonal to the thickness direction T. The second conductor layer 40 includes second extended wiring parts 41E and at least one dummy pattern 43. The second extended wiring parts 41E extend in a second direction D2 orthogonal to the thickness direction T and crossing the first direction D1. The dummy pattern 43 is arranged between adjacent two second extended wiring parts 41E so as to extend in the second direction D2.SELECTED DRAWING: Figure 2

Description

The present invention relates to a wired circuit board.

A flexible wired circuit board is known that includes a flexible base material and a wiring pattern on the base material. A flexible printed circuit board may be folded during use, such as being assembled in a device in a folded state. Such a flexible printed circuit board is described, for example, in Patent Document 1 below.

JP-A-2005-93447

Conventionally, in a flexible printed circuit board that is bent during use, wiring that crosses the bent portion may be broken at the bent portion (bent portion).

The present invention provides a wired circuit board suitable for suppressing breakage of wiring and having bent portions.

The present invention [1] comprises a first insulating layer, a first conductor layer, a second insulating layer, a second conductor layer, and a third insulating layer in this order in the thickness direction, A conductor layer includes a plurality of first extending wiring portions extending in a first direction perpendicular to the thickness direction, and the second conductor layer includes a second conductor layer perpendicular to the thickness direction and crossing the first direction. a wiring circuit including a plurality of second extending wiring portions extending in a direction and at least one dummy pattern, wherein the dummy pattern is arranged between two adjacent second extending wiring portions and extends in the second direction; Including substrate.

In the wired circuit board of the present invention, as described above, the second conductor layer includes dummy patterns extending in the second direction. In such a printed circuit board, the center position (first center position) in the thickness direction of the printed circuit board can be adjusted at the place where the dummy pattern is formed by adjusting the thickness of the dummy pattern. Therefore, when the printed circuit board is bent along the dummy pattern, the bent portion is designed to reduce the tensile stress and compressive stress generated in the first extended wiring portion (crossing the bent portion) at the bent portion (bent portion). can adjust the distance from the first center position to the thickness direction center position (second center position) of the first extending wiring portion (the distance between the first center position and the second center position is too long). Then, the tensile stress and compressive stress generated in the first extended wiring portion at the bent portion become excessive, and the first extended wiring portion is broken). Further, in this wired circuit board, the second extended wiring portion extends in the second direction similarly to the dummy pattern. Such a configuration suppresses the occurrence of tensile stress and compressive stress due to the bending in the second extended wiring portion (not crossing the bent portion) when the wired circuit board is bent along the dummy pattern. Suitable for Therefore, this printed circuit board is suitable for suppressing breakage of the wiring and having a bent portion along the dummy pattern formation portion.

The present invention [2] further comprises a third conductor layer and a fourth insulation layer in this order from the third insulation layer side on the side opposite to the second conductor layer in the third insulation layer, The wired circuit board according to [1] above, wherein the third conductor layer includes at least one third extending wiring portion extending in the second direction facing the dummy pattern via the third insulating layer. .

Such a configuration is suitable for achieving high density while suppressing breakage in wiring arranged on the second and third conductor layer sides of the second insulating layer.

The present invention [3] includes the wired circuit board according to [1] or [2] above, wherein the first extended wiring portion is thinner than the second extended wiring portion.

Such a configuration is preferable from the viewpoint of suppressing breakage of the first extended wiring portion.

The present invention [4] includes the printed circuit board according to any one of [1] to [3], wherein the dummy pattern is thinner than the second extended wiring portion.

Such a configuration is suitable for finely adjusting the central position in the thickness direction of the bent portion of the printed circuit board using a dummy pattern.

The present invention [5] is any one of [1] to [4] above, wherein the second extended wiring portion includes a first layer on the second insulating layer side and a second layer on the first layer. A wired circuit board according to one.

Such a configuration is preferable from the viewpoint of increasing the thickness of the second extended wiring portion.

In the present invention [6], each of the plurality of first extending wiring portions includes a first thick portion, a second thick portion, and the first thick portion in the extending direction of the first extending wiring portion. and a thin portion extending from the second thick portion to the second thick portion, and the plurality of thin portions of the plurality of first extending wiring portions extends in the second direction facing the dummy pattern with the second insulating layer interposed therebetween. The printed circuit board according to any one of [1] to [5] is arranged side by side.

Such a configuration is preferable in terms of achieving both a reduction in resistance and suppression of breakage at the bent portion in the first extended wiring portion.

1 is a plan view of a first embodiment of a wired circuit board of the present invention; FIG. 2 is a partially enlarged cross-sectional view along a first direction in the printed circuit board shown in FIG. 1; FIG. 2 is a partially enlarged cross-sectional view along a second direction in the printed circuit board shown in FIG. 1; FIG. 2 is a partially enlarged cross-sectional view showing via connection between first wiring and second wiring in the printed circuit board shown in FIG. 1; FIG. An example of a manufacturing method of the printed circuit board shown in FIG. 1 is represented. 5A represents the first conductor layer forming step, FIG. 5B represents the second insulating layer forming step, FIG. 5C represents the second conductor layer forming step, and FIG. 5D represents the third edge layer forming step. 1 shows one bending mode of the printed circuit board shown in FIG. 2 shows another bending mode of the wired circuit board shown in FIG. FIG. 4 is a partially enlarged cross-sectional view along the first direction in one modification of the printed circuit board shown in FIG. 1 ; FIG. 3 is a partial cross-sectional view of a modification of the printed circuit board shown in FIG. 1; In this modification, the first extended wiring portion has a thick portion and a thin portion. FIG. 3 is a partial cross-sectional view of a modification of the printed circuit board shown in FIG. 1; In this modification, the dummy pattern is thinner than the second extended wiring portion, and the second extended wiring portion has a single layer structure. FIG. 3 is a partial cross-sectional view of a modification of the printed circuit board shown in FIG. 1; In this modification, the dummy pattern is thinner than the second extended wiring portion, and the second extended wiring portion has a two-layer structure. FIG. 3 is a partial cross-sectional view of a modification of the printed circuit board shown in FIG. 1; In this modification, the first extended wiring portion has a thick portion and a thin portion, the dummy pattern is thinner than the second extended wiring portion, and the second extended wiring portion has a single layer structure. FIG. 3 is a partial cross-sectional view of a modification of the printed circuit board shown in FIG. 1; In this modification, the first extended wiring portion has a thick portion and a thin portion, the dummy pattern is thinner than the second extended wiring portion, and the second extended wiring portion has a two-layer structure. FIG. 4 is a plan view of a second embodiment of the wired circuit board of the present invention; 15 is a partially enlarged cross-sectional view along the first direction in the printed circuit board shown in FIG. 14; FIG. 15 shows a part of the steps in the method of manufacturing the wired circuit board shown in FIG. 14; 16A represents the third conductor layer forming step, and FIG. 16B represents the fourth insulating layer forming step.

A wired circuit board X1 as a first embodiment of the wired circuit board of the present invention comprises a first insulating layer 10, a first conductor layer 20, and a second insulating layer 30, as shown in FIGS. , a second conductor layer 40, and a third insulating layer 50 (not shown in FIG. 1) in the thickness direction T in this order. The printed circuit board X1 extends in a direction (surface direction) orthogonal to the thickness direction T and has a predetermined planar shape (the planar view shape shown in FIG. 1 for the printed circuit board X1 is an exemplary shape). The printed circuit board X1 is, for example, a flexible printed wiring board (FPC), and can be used, for example, as an FPC cable.

The first insulating layer 10 is an insulating base material as a base insulating layer. In a plan view shown in FIG. 1, the outer shape of the first insulating layer 10 forms the outer shape of the wired circuit board X1. Examples of the material of the first insulating layer 10 include a resin film. Examples of the resin film include polyimide film, polyester film, polyethylene terephthalate film, polyethylene naphthalate film, and polycarbonate film, and polyimide film is preferably used.

From the viewpoint of the strength of the first insulating layer 10 (insulating base material), the thickness of the first insulating layer 10 is preferably 1 μm or more, more preferably 3 μm or more, and even more preferably 5 μm or more. From the viewpoint of flexibility of the first insulating layer 10, the thickness of the first insulating layer 10 is preferably 50 μm or less, more preferably 30 μm or less, and even more preferably 25 μm or less.

The first conductor layer 20 is arranged on one side in the thickness direction T of the first insulating layer 10 . In this embodiment, the first conductor layer 20 is arranged on one surface in the thickness direction T of the first insulating layer 10 . The first conductor layer 20 includes a plurality of wirings 21 and a plurality of first terminal portions 22, and has a predetermined pattern shape. FIG. 1 exemplarily shows a pattern shape in which each wiring 21 extends in the first direction D1. Examples of the material of the first conductor layer 20 include copper, nickel, gold, and alloys thereof, and copper is preferably used (as a material of the second conductor layer 40 and the third conductor layer 60 described later). is also the same).

The plurality of wirings 21 includes a plurality of wirings 21A (first wirings) and a plurality of wirings 21B, as shown in FIG.

In this embodiment, the wiring 21A has a first extending wiring portion 21E extending in the first direction D1 from near one end of the printed circuit board X1 to near the other end in the first direction D1 (that is, the first conductor layer 20 includes a first extended wiring portion 21E). FIG. 1 exemplifies the case where the wiring 21A has the first extended wiring portion 21E over the entirety (that is, the wiring 21A extends in the first direction D1). The first direction D1 is one direction orthogonal to the thickness direction T. As shown in FIG. The plurality of first extending wiring portions 21E in the plurality of wirings 21A are arranged at intervals in a direction orthogonal to the first direction D1 in plan view shown in FIG. In this embodiment, the wiring 21B extends from near the end of the printed circuit board X1 toward the center in the first direction D1.

Width of wiring 21 (wiring 21A, wiring 21B) (dimension in the direction perpendicular to the extending direction of wiring 21 in plan view) is preferably 5 μm or more, more preferably 10 μm or more, and preferably 1000 μm or less, or more preferably 1000 μm or less. It is preferably 750 μm or less. The distance between adjacent wirings 21 is preferably 5 μm μm or more, more preferably 10 μm μm or more, and preferably 5000 μm or less, more preferably 3000 μm or less. The thickness of the wiring 21 is preferably 1 μm or more, more preferably 2 μm or more, still more preferably 3 μm or more, and is preferably 20 μm or less, more preferably 17 μm or less, still more preferably 15 μm or less. The wiring 21 is preferably thinner than the wiring 41 described later in the second conductor layer 40 . Also, the first extension wiring portion 21E of the wiring 21A is preferably thinner than the second extension wiring portion 41E of the second conductor layer 40, which will be described later.

The first terminal portion 22 is arranged at the end portion of the wiring 21 . The plurality of first terminal portions 22 are spaced apart from each other in a direction orthogonal to the first direction D1 in plan view shown in FIG. In FIG. 1 , a plurality of first terminal portions 22 are arranged in a line on one end side in the first direction D1 on the first insulating layer 10, and on the other end side in the first direction D1 on the first insulating layer 10 An arrangement in which the plurality of first terminal portions 22 are arranged in a row is exemplarily shown.

The planar view shape of the first terminal portion 22 is wider than the wiring 21 in the second direction D2. Examples of the planar shape of the first terminal portion 22 include a circle, a square, and a square with rounded corners (the same applies to the planar shape of the second terminal portion 42 and the third terminal portion 62 described below). Quadrilaterals include squares and rectangles. The rounded square includes a rounded square and a rounded rectangle (the case where the first terminal portion 22 has a rectangular shape in plan view is illustrated as an example).

The thickness of the first terminal portion 22 is preferably 1 μm or more, more preferably 2 μm or more, still more preferably 3 μm or more, and is preferably 20 μm or less, more preferably 17 μm or less, still more preferably 15 μm or less. The thickness of the first terminal portion 22 may be the same as or different from the thickness of the wiring 21 .

The second insulating layer 30 is an intermediate insulating layer. The second insulating layer 30 is arranged on one side of the first insulating layer 10 in the thickness direction T so as to partially cover the first conductor layer 20 . In this embodiment, the second insulating layer 30 is arranged on one surface in the thickness direction T of the first insulating layer 10 so as to cover the plurality of wirings 21 . In addition, the second insulating layer 30 has via holes H in which via holes V described later are arranged, as shown in FIG.

Examples of the material of the second insulating layer 30 include resin materials such as polyimide, polyethernitrile, polyethersulfone, polyethylene terephthalate, polyethylene naphthalate, and polyvinyl chloride, and polyimide is preferably used (described later). The same applies to the materials of the third insulating layer 50 and the fourth insulating layer 70). The thickness of the second insulating layer 30 (thickness between the first conductor layer 20 and the second conductor layer 40) is preferably 1 μm or more, more preferably 3 μm or more, and is preferably 15 μm or less, more preferably 1 μm or more. It is preferably 10 μm or less.

The second conductor layer 40 is arranged on one side in the thickness direction T of the second insulating layer 30 . In this embodiment, the second conductor layer 40 is arranged on one surface in the thickness direction T of the second insulating layer 30 . The second conductor layer 40 includes a plurality of wirings 41 (second wirings), a plurality of second terminal portions 42, and dummy patterns 43, and has a predetermined pattern shape. FIG. 1 exemplarily shows a pattern shape in which each wiring 41 extends in the second direction D2.

As shown in FIG. 1, the wiring 41 has a second extending wiring portion 41E extending in the second direction D2 from near one end of the printed circuit board X1 toward the other end in the second direction D2 (that is, the second extending wiring portion 41E). The two-conductor layer 40 includes a second extended wiring portion 41E). FIG. 1 exemplifies the case where the wiring 41 has the second extended wiring portion 41E over the entirety (that is, the case where the wiring 41 extends in the second direction D2). The second direction D2 is a direction orthogonal to the thickness direction T and crosses the first direction D1. That is, the extension direction (second direction D2) of the second extension wiring portion 41E and the extension direction (first direction D1) of the first extension wiring portion 21E described above intersect. The first direction D1 and the second direction D2 may be orthogonal. The plurality of second extending wiring portions 41E in the plurality of wirings 41 are arranged at intervals in a direction perpendicular to the second direction D2 in plan view shown in FIG. Also, the wiring 41 is connected to the wiring 21B through the via V. As shown in FIG. Specifically, as shown in FIG. 4, the end of the wiring 41 opposite to the end connected to the second terminal portion 42, which will be described later, has a thickness of the second insulating layer 30 between the conductor layers 20 and 40. Via a via V (conductive via) penetrating in the vertical direction T, the wiring 21B is connected to the end opposite to the end connected to the first terminal portion 22 .

The width of the wiring 41 (dimension in the direction orthogonal to the extending direction of the wiring 41 in plan view) is preferably 5 μm or more, more preferably 10 μm or more, and preferably 1000 μm or less, more preferably 750 μm or less. The distance between the wirings 41 adjacent to each other without the dummy pattern 43 interposed therebetween is preferably 5 μm or more, more preferably 10 μm or more, and is preferably 5000 μm or less, more preferably 3000 μm or less. The separation distance between adjacent wirings 41 via the dummy pattern 43 is, for example, 10 to 10000 μm depending on the width of the dummy pattern 43 . The thickness of the wiring 41 is preferably 1 μm or more, more preferably 2 μm or more, still more preferably 3 μm or more, and is preferably 20 μm or less, more preferably 17 μm or less, still more preferably 15 μm or less.

The second terminal portion 42 is arranged at the end portion of the wiring 41 . The planar view shape of the second terminal portion 42 is wider than the wiring 41 in the first direction D1. The plurality of second terminal portions 42 are spaced apart from each other in a direction orthogonal to the second direction D2 in plan view shown in FIG. FIG. 1 exemplarily shows an arrangement in which a plurality of second terminal portions 42 are arranged in a line on one end side in the second direction D2 on the second insulating layer 30 .

The thickness of the second terminal portion 42 is preferably 1 μm or more, more preferably 2 μm or more, still more preferably 3 μm or more, and is preferably 20 μm or less, more preferably 17 μm or less, still more preferably 15 μm or less. The thickness of the second terminal portion 42 may be the same as or different from the thickness of the wiring 41 .

The dummy pattern 43 is arranged between two adjacent wirings 41 along a portion of the printed circuit board X1 that is expected to be bent, and extends in the second direction D2.

The width of the dummy pattern 43 (dimension in the direction orthogonal to the extending direction of the dummy pattern 43 in plan view) is preferably larger than the width of the wiring 41, preferably 10 μm or more, more preferably 20 μm or more, and preferably It is 10000 μm or less, more preferably 8000 μm or less. The ratio of the width of the dummy pattern 43 to the width of the wiring 41 is preferably 2 or more, more preferably 3 or more, and is preferably 20 or less, more preferably 15 or less.

The thickness of the dummy pattern 43 is preferably 1 μm or more, more preferably 2 μm or more, still more preferably 3 μm or more, and is preferably 20 μm or less, more preferably 17 μm or less, still more preferably 15 μm or less. The thickness of the dummy pattern 43 may be the same as or different from the thickness of the wiring 41 (FIGS. 2 and 3 illustrate the case where they are the same). The ratio of the thickness of the dummy pattern 43 to the thickness of the wiring 41 is preferably 0.1 or more, more preferably 0.2 or more, and is preferably 10 or less, more preferably 5 or less. By adjusting the thickness of the dummy pattern 43, the central position C in the thickness direction T of the printed circuit board X1 can be adjusted at the position where the dummy pattern 43 is formed (the central position C is exemplified in FIG. 2). The separation distance between the dummy pattern 43 and the wiring 41 is preferably 10 μm or more, more preferably 20 μm or more, and is preferably 2000 μm or less, more preferably 1000 μm or less.

The third insulating layer 50 is a cover insulating layer. The third insulating layer 50 is arranged on one side of the second insulating layer 30 in the thickness direction T so as to partially cover the second conductor layer 40 . In this embodiment, the third insulating layer 50 is arranged on one surface in the thickness direction T of the second insulating layer 30 so as to cover the multiple wirings 41 and the dummy patterns 43 . The thickness of the third insulating layer 50 (thickness on the second conductor layer 40) is preferably 1 μm or more, more preferably 3 μm or more, and is preferably 15 μm or less, more preferably 10 μm or less.

FIG. 5 shows an example of a method for manufacturing the printed circuit board X1. FIG. 5 represents this manufacturing method as a cross-sectional variation corresponding to FIG.

In this manufacturing method, first, as shown in FIG. 5A, the first conductor layer 20 is formed on one surface in the thickness direction T of the first insulating layer 10 (insulating base material) (first conductor layer forming step ). In this step, first, a seed layer (not shown) is formed on the first insulating layer 10 by sputtering, for example. Examples of seed layer materials include Cr, Cu, Ni, Ti, and alloys thereof. The seed layer may have a single layer structure or a multilayer structure of two or more layers. When the seed layer has a multi-layer structure, the seed layer is composed of, for example, a chromium layer as a lower layer and a copper layer on the chromium layer (the material and structure of the seed layer are the same for the seed layer described later). is). Next, a resist pattern is formed on the seed layer. The resist pattern has an opening with a shape corresponding to the pattern shape of the first conductor layer 20 . In forming a resist pattern, for example, after a photosensitive resist film is laminated on a seed layer to form a resist film, the resist film is exposed through a predetermined mask and then developed. , and then baking if necessary (this also applies to the formation of a resist pattern, which will be described later). In forming the first conductor layer 20, the above-described metal is then grown on the seed layer in the openings of the resist pattern by, for example, electroplating. Next, the resist pattern is removed by etching. Next, the portion of the seed layer exposed by removing the resist pattern is removed by etching. For example, the first conductor layer 20 (wiring 21, first terminal portion 22) having a predetermined pattern can be formed as described above.

Next, as shown in FIG. 5B, a second insulating layer 30 is formed on the first insulating layer 10 so as to cover a portion (wiring 21) of the first conductor layer 20 (second insulating layer forming step). . In this step, first, a photosensitive resin solution (varnish) is applied on the first insulating layer 10 so as to partially cover the first conductor layer 20 to form a coating film. The coating is then dried by heating. Next, the coating film is subjected to exposure processing through a predetermined mask, development processing after that, and baking processing if necessary. For example, the second insulating layer 30 having a predetermined pattern can be formed as described above.

Next, as shown in FIG. 5C, the second conductor layer 40 is formed on the second insulating layer 30 (second conductor layer forming step). In this step, first, a seed layer (not shown) is formed on the second insulating layer 30 and in the via hole H by, for example, sputtering. Next, a resist pattern is formed on the seed layer. The resist pattern has an opening with a shape corresponding to the pattern shape of the second conductor layer 40 . Next, the above-described metal is grown on the seed layer in the openings of the resist pattern by, eg, electroplating. Next, the resist pattern is removed by etching. Next, the portion of the seed layer exposed by removing the resist pattern is removed by etching. For example, as described above, the second conductor layer 40 (wiring 41, second terminal portion 42, dummy pattern 43) can be formed in a predetermined pattern (in this step, the via hole H of the second insulating layer 30 also includes the via V). can be formed).

Next, as shown in FIG. 5D, a third insulating layer 50 is formed on the second insulating layer 30 so as to cover a portion of the second conductor layer 40 (wiring 41, dummy pattern 43) (third insulating layer 40). layer forming step). In this step, first, a photosensitive resin solution (varnish) is applied on the second insulating layer 30 so as to partially cover the second conductor layer 40 to form a coating film. The coating is then dried by heating. Next, the coating film is subjected to exposure processing through a predetermined mask, development processing after that, and baking processing if necessary. For example, the third insulating layer 50 can be formed as described above.

As described above, the printed circuit board X1 can be manufactured.

6 and 7 show the case where the flexible wired circuit board X1 is bent along the formation location of the dummy pattern 43 (that is, the case where it has a bent portion along the formation location of the dummy pattern 43). At the bent portion of the wired circuit board X1, the first extended wiring portion 21E (wiring 21A) is bent outside (the upper surface side of the first extended wiring portion 21E in FIG. 6, the lower surface side of the first extended wiring portion 21E in FIG. 7). A tensile stress is generated in the first extended wiring portion 21E, and a compressive stress is generated in the curved inner side of the first extended wiring portion 21E (the lower surface side of the first extended wiring portion 21E in FIG. 6 and the upper surface side of the first extended wiring portion 21E in FIG. 7).

The printed circuit board X1 is suitable for suppressing breakage of the wiring 21A and the wiring 41 and having a bent portion along the formation location of the dummy pattern 43 (extending in the second direction D2). The reason is as follows.

In the printed circuit board X1, as described above, the second conductor layer 40 includes the dummy pattern 43 extending in the second direction D2. In such a wired circuit board X1, by adjusting the thickness of the dummy pattern 43, the central position C in the thickness direction T of the wired circuit board X1 can be adjusted at the position where the dummy pattern 43 is formed. If the distance between the center position C and the center position in the thickness direction of the first extended wiring portion 21E of the wiring 21A is too long, the bent portion may be bent when the wired circuit board X1 is bent along the dummy pattern 43. The tensile stress and compressive stress generated in the first extended wiring portion 21E (crossing the bent portion) at (the bent portion) become excessive, and the first extended wiring portion 21E breaks. On the other hand, in the wired circuit board X1, in order to reduce the tensile stress and compressive stress generated in the first extended wiring portion 21E at the bent portion of the wired circuit board X1, the first extension from the center position C at the bent portion is performed. The distance to the central position in the thickness direction of the extended wiring portion 21E can be adjusted.

Further, in the printed circuit board X1, the wiring 41 extends in the second direction in the same manner as the dummy pattern 43 does. Such a configuration suppresses the occurrence of tensile stress and compressive stress in the wiring 41 (not crossing the bent portion) due to the bending when the wired circuit board X1 is bent along the dummy pattern 43. Suitable.

Therefore, the printed circuit board X1 is suitable for suppressing breakage of the wiring (wiring 21A, wiring 41) and having a bent portion along the formation location of the dummy pattern 43. FIG.

The first wire extension portion 21E is preferably thinner than the second wire extension portion 41E, as described above. Such a configuration reduces the difference in tensile stress and compressive stress generated on one side and the other side in the thickness direction T of the first extended wiring portion 21E when the wired circuit board X1 is folded along the dummy pattern 43. Therefore, it is suitable for suppressing breakage of the first extended wiring portion 21E (wiring 21A).

In the printed circuit board X1, as shown in FIG. 8, a plurality of dummy patterns 43 may be provided (a case where three dummy patterns 43 are provided is shown as an example). In this modification, wirings 41 and dummy patterns 43 are alternately arranged in the second conductor layer 40 . Such a configuration is suitable for arranging the wirings 41 at a high density while securing the total area of the regions where the dummy patterns 43 are formed. The fact that such a plurality of dummy patterns 43 may be provided is the same in modifications described later.

In the wired circuit board X1, each of the plurality of first extending wiring portions 21E in the plurality of wirings 21A extends in the extending direction (first direction D1) of the first extending wiring portion 21E, as shown in FIG. It may have a first thick portion 21a, a second thick portion 21b, and a thin portion 21c extending from the first thick portion 21a to the second thick portion 21b. The plurality of thin portions 21c in the plurality of first extended wiring portions 21E are arranged in the second direction D2 so as to face the dummy pattern 43 via the second insulating layer 30 (the dummy pattern 43 has a thin portion 21c in plan view). overlap). Also, the first thick portion 21a and the second thick portion 21b have a two-layer structure of the first layer 20a and the second layer 20b. The first terminal portion 22 (not shown) also has a two-layer structure of a first layer 20a and a second layer 20b. The thin portion 21c has a single layer structure of the first layer 20a.

The thickness of the first thick portion 21a and the thickness of the second thick portion 21b are each preferably 2 μm or more, more preferably 3 μm or more, still more preferably 5 μm or more, and preferably 20 μm or less and more preferably 2 μm or more. It is preferably 17 μm or less, more preferably 15 μm or less. The thickness of the first thick portion 21a and the thickness of the second thick portion 21b are preferably the same. The thickness of the thin portion 21c is preferably 1 μm or more, more preferably 2 μm or more, and still more preferably 3 μm or more, as long as it is smaller than the thickness of the first thick portion 21a and the thickness of the second thick portion 21b, Also, it is preferably 15 μm or less, more preferably 12 μm or less, and still more preferably 10 μm or less. The ratio of the thickness of the thin portion 21c to the thickness of the first thick portion 21a and/or the thickness of the second thick portion 21b is preferably 0.1 or more, more preferably 0.2 or more, and even more preferably. is 0.3 or more, preferably 0.9 or less, more preferably 0.8 or less, and still more preferably 0.7 or less.

In this modification, the width of the dummy pattern 43 is smaller than the length of the thin portion 21c in the first direction D1. The ratio of the width of the dummy pattern 43 to the length of the thin portion 21c in the first direction D1 is preferably 0.1 or more, more preferably 0.2 or more, and preferably 0.99 or less, more preferably. 0.9 or less.

In the first conductor layer forming step (FIG. 5A), for example, after forming the first layer 20a by the first electroplating method, the second layer 20b is formed on the first layer 20a by the second electroplating method. Accordingly, the first thick portion 21a, the second thick portion 21b, and the thin portion 21c can be provided. In the first electroplating method, a resist pattern having an opening with a shape corresponding to the pattern shape of the first layer 20a is used. In the second electroplating method, a resist pattern having an opening with a shape corresponding to the pattern shape of the second layer 20b is used.

The configuration in which each first extended wiring portion 21E has a thin portion 21c facing the dummy pattern 43 with the second insulating layer 30 interposed therebetween is such that the first extended wiring portion 21E of each wiring 21A has a low resistance and a bending portion. It is preferable in terms of achieving compatibility with the suppression of breakage.

In the printed circuit board X1, as shown in FIGS. 10 and 11, the dummy pattern 43 may be thinner than the second extended wiring portion 41E (wiring 41). Such a configuration is suitable for fine adjustment of the center position C using a dummy pattern. Further, when the dummy pattern 43 is thinner than the second extended wiring portion 41E, the second extended wiring portion 41E may have a single layer structure as shown in FIG. 10, or may have a two-layer structure as shown in FIG. It may have a structure. A second extended wiring portion 41E shown in FIG. 11 includes a first layer 40a on the side of the second insulating layer 30 and a second layer 42 on the first layer 40a (a second terminal portion 42 not shown in the figure also (having a first layer 40a and a second layer 40b). Such a configuration is preferable from the viewpoint of increasing the thickness of the second extended wiring portion 41E with high accuracy. In the second conductor layer forming step (FIG. 5C), for example, after forming the wiring 41 and the second terminal portion 42 by the third electroplating method, by forming the dummy pattern 43 by the fourth electroplating method, Wiring 41 and dummy patterns 43 shown in FIG. 10 can be provided. In the third electroplating method, a resist pattern having openings with shapes corresponding to the pattern shapes of the wiring 41 and the second terminal portion 42 is used. In the fourth electroplating method, a resist pattern having an opening with a shape corresponding to the pattern shape of the dummy pattern 43 is used. In the second conductor layer forming step, for example, after forming the first layer 40a and the dummy pattern 43 by the fifth electroplating method, the second layer 40b is formed on the first layer 40a by the sixth electroplating method. By forming them, the wiring 41 and the dummy pattern 43 shown in FIG. 11 can be provided. In the fifth electroplating method, a resist pattern having openings with shapes corresponding to the pattern shapes of the first layer 40a and the dummy pattern 43 is used. In the sixth electroplating method, a resist pattern having an opening with a shape corresponding to the pattern shape of the second layer 40b is used.

In the wired circuit board X1, as shown in FIGS. 12 and 13, each of the plurality of first extended wiring portions 21E has a first thick portion 21a, a second thick portion 21b, and a thin portion 21c. Moreover, the dummy pattern 43 may be thinner than the wiring 41 . The first thick portion 21a, the second thick portion 21b, and the thin portion 21c are as described above with reference to FIG. The wiring 41 and dummy pattern 43 shown in FIG. 12 are the same as the wiring 41 and dummy pattern 43 shown in FIG. Wiring 41 and dummy pattern 43 shown in FIG. 13 are the same as wiring 41 and dummy pattern 43 shown in FIG. In the modification shown in FIGS. 12 and 13, in the first extension wiring portion 21E of the wiring 21A, the center position C is finely adjusted by a dummy pattern while achieving both low resistance and suppression of breakage at the bent portion. suitable for

14 and 15 show a wired circuit board X2 as a second embodiment of the wired circuit board of the present invention. The printed circuit board X2 includes a first insulating layer 10, a first conductor layer 20, a second insulating layer 30, a second conductor layer 40, a third insulating layer 50, a third conductor layer 60, a fourth An insulating layer 70 (not shown in FIG. 14) is provided in the thickness direction T in this order. The printed circuit board X2 further includes a third conductor layer 60 and a fourth insulation layer 70 in this order from the third insulation layer 50 side on the side of the third insulation layer 50 opposite to the second conductor layer 40. , different from the wired circuit board X1 (the planar view shape shown as an example is also different from the wired circuit board X1). Except for this, the wired circuit board X2 has the same configuration as the wired circuit board X1.

The third conductor layer 60 is arranged on one side in the thickness direction T of the third insulating layer 50 . In this embodiment, the third conductor layer 60 is arranged on one surface in the thickness direction T of the third insulating layer 50 . The third conductor layer 60 includes a plurality of wirings 61 (third wirings) and a plurality of third terminal portions 62, and has a predetermined pattern shape (when the third conductor layer 60 includes two wirings 61, are shown exemplarily). FIG. 14 exemplarily shows a pattern shape in which the third terminal portions 62 are arranged at both ends of the wiring 61 .

As shown in FIG. 14, the wiring 61 has a third extending wiring portion 61E extending in the second direction D2 (that is, the third conductor layer 60 includes the third extending wiring portion 61E). The third extended wiring portion 61E has a portion facing the dummy pattern 43 with the third insulating layer 50 interposed therebetween, as shown in FIG. The plurality of third extension wiring portions 61E are arranged at intervals in a direction orthogonal to the second direction D2 in plan view shown in FIG.

The width of the wiring 61 (the dimension in the direction orthogonal to the extending direction of the wiring 61 in plan view) is preferably 5 μm or more, more preferably 10 μm or more, and preferably 1000 μm or less, more preferably 750 μm or less. The distance between adjacent wirings 61 is preferably 5 μm or more, more preferably 10 μm or more, and preferably 5000 μm or less, more preferably 3000 μm or less. The thickness of the wiring 61 is preferably 1 μm or more, more preferably 2 μm or more, still more preferably 3 μm or more, and is preferably 20 μm or less, more preferably 17 μm or less, still more preferably 15 μm or less.

The third terminal portion 62 is arranged at the end portion of the wiring 61 . The thickness of the third terminal portion 62 is preferably 1 μm or more, more preferably 2 μm or more, still more preferably 3 μm or more, and is preferably 20 μm or less, more preferably 17 μm or less, still more preferably 15 μm or less. The thickness of the third terminal portion 62 may be the same as or different from the thickness of the wiring 61 .

The fourth insulating layer 70 is a cover insulating layer. The fourth insulating layer 70 is arranged to cover the third conductor layer 60 on one side in the thickness direction T of the third insulating layer 50 . In this embodiment, the fourth insulating layer 70 is arranged on one surface in the thickness direction T of the third insulating layer 50 so as to cover the wiring 61 . The thickness of the fourth insulating layer 70 (thickness on the third conductor layer 60) is preferably 1 μm or more, more preferably 3 μm or more, and is preferably 15 μm or less, more preferably 10 μm or less.

The printed circuit board X2 can be manufactured by performing, for example, the following third conductor layer forming process and fourth insulating layer forming process after the series of processes described above with reference to FIG.

In the third conductor layer forming step, the third conductor layer 60 is formed on the third insulating layer 50, as shown in FIG. 16A. In this step, first, a seed layer (not shown) is formed on the third insulating layer 50 by sputtering, for example. Next, a resist pattern is formed on the seed layer. The resist pattern has an opening with a shape corresponding to the pattern shape of the third conductor layer 60 . Next, the above-described metal is grown on the seed layer in the openings of the resist pattern by, eg, electroplating. Next, the resist pattern is removed by etching. Next, the portion of the seed layer exposed by removing the resist pattern is removed by etching. For example, the third conductor layer 60 (wiring 61, third terminal portion 62) having a predetermined pattern can be formed as described above.

Next, in the third insulating layer forming step, as shown in FIG. 16B, a fourth insulating layer 70 is formed on the third insulating layer 50 so as to cover a portion of the third conductor layer 60 (wiring 61). . In this step, first, a photosensitive resin solution (varnish) is applied on the third insulating layer 50 so as to partially cover the third conductor layer 60 to form a coating film. The coating is then dried by heating. Next, the coating film is subjected to exposure processing through a predetermined mask, development processing after that, and baking processing if necessary. For example, the fourth insulating layer 70 can be formed as described above.

As with the wired circuit board X1, the thickness of the dummy pattern 43 of the wired circuit board X2 can be adjusted to adjust the center position of the wired circuit board X2 in the thickness direction T at the position where the dummy pattern 43 is formed. Therefore, when the wired circuit board X2 is bent along the dummy pattern 43, the bent portion is designed to reduce tensile stress and compressive stress generated in the wiring 21 (crossing the bent portion) at the bent portion (bent portion). , the distance from the center position to the thickness direction center position of the first extension wiring portion 21E of the wiring 21A can be adjusted. Further, in the printed circuit board X2, the second extended wiring portion 41E (wiring 41) and the third extending wiring portion 61E (wiring 61) extend in the second direction like the dummy pattern 43. Such a configuration is caused by the bending of the second extended wiring portion 41E and the third extended wiring portion 61E (both of which do not cross the bent portion) when the wired circuit board X2 is bent along the dummy pattern 43. Suitable for suppressing the generation of tensile stress and compressive stress. Therefore, the printed circuit board X2 suppresses breakage of the first extended wiring portion 21E (wiring 21A), the second extended wiring portion 41E (wiring 41), and the third extended wiring portion 61E (wiring 61), while preventing the dummy pattern 43 from breaking. It is suitable for having a bent portion along the formation point of. In addition, the printed circuit board X2 is suitable for increasing the density of wiring (wiring 41, wiring 61) arranged on the second conductor layer 40 side of the second insulating layer 30 while suppressing breakage.

9 to 13 described above with respect to the wired circuit board X1 can also be applied to the wired circuit board X2.

X1, X2 Wiring circuit board T Thickness direction D1 First direction D2 Second direction 10 First insulating layer 20 First conductor layer 21 Wiring 21A Wiring (first wiring)
21E First extended wiring portion 21a First thick portion 21b Second thick portion 21c Thin portion 30 Second insulating layer 40 Second conductor layer 40a First layer 40b Second layer 41 Wiring (second wiring)
41E Second extended wiring portion 43 Dummy pattern 50 Third insulating layer 60 Third conductor layer 61 Wiring (third wiring)
61E Third extended wiring portion 70 Fourth insulating layer

Claims (6)

A first insulating layer, a first conductor layer, a second insulating layer, a second conductor layer, and a third insulating layer are provided in this order in the thickness direction,
the first conductor layer includes a plurality of first extending wiring portions extending in a first direction orthogonal to the thickness direction;
the second conductor layer includes a plurality of second extending wiring portions extending in a second direction orthogonal to the thickness direction and crossing the first direction, and at least one dummy pattern;
The wired circuit board, wherein the dummy pattern is arranged between two adjacent second extended wiring portions and extends in the second direction. A third conductor layer and a fourth insulation layer are further provided in this order from the third insulation layer side on the side opposite to the second conductor layer in the third insulation layer,
2. The printed circuit board according to claim 1, wherein said third conductor layer includes at least one third extending wiring part extending in said second direction facing said dummy pattern via said third insulating layer. 3. The printed circuit board according to claim 1, wherein said first extended wiring portion is thinner than said second extended wiring portion. 4. The wired circuit board according to claim 1, wherein said dummy pattern is thinner than said second extended wiring portion. 5. The printed circuit board according to claim 1, wherein said second conductor layer includes a first layer on said second insulating layer side and a second layer on said first layer. Each of the plurality of first extending wiring portions includes a first thick portion, a second thick portion, and from the first thick portion to the second thick portion in the extending direction of the first extending wiring portion. and a thin portion extending to
6. The wiring according to any one of claims 1 to 5, wherein a plurality of thin portions in said plurality of first extended wiring portions are arranged in said second direction facing said dummy pattern via said second insulating layer. circuit board.

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