Wired circuit board

Abstract

To provide a wiring circuit board capable of suppressing warpage.SOLUTION: The wired circuit board 1 sequentially includes a metal supporting layer 4, a base insulating layer 5, and a conductive layer 6 toward one side in the thickness direction. One surface 43 in the thickness direction of the metal supporting layer 4 includes a facing surface 44 that faces the other surface 54 in the thickness direction of the base insulating layer 5 in the thickness direction. The facing surface 44 includes a joining surface 45 and a non-joining surface 46. The joining surface 45 is joined to the other surface 54. The non-joining surface 46 is not joined to the other surface 54.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a printed circuit board. [Background technology]

[0002] There is known a wired circuit board that includes a metal support layer, an insulating layer, and a conductor layer in this order toward one side in the thickness direction (see, for example, Patent Document 1 below). In the wired circuit board described in Patent Document 1, one surface in the thickness direction of the metal support layer includes an opposing surface that faces the other surface in the thickness direction of the insulating layer. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Application No. 2019-212656 Summary of the Invention [Problem to be solved by the invention]

[0004] In Patent Document 1, the entire opposing surface is bonded to the other surface. However, there is a large difference between the linear expansion coefficient of the metal support layer and the linear expansion coefficient of the insulating layer. Therefore, the wired circuit board described in Patent Document 1 has the disadvantage of being prone to warping.

[0005] The present invention provides a wired circuit board capable of suppressing warpage. [Means for solving the problem]

[0006] The present invention (1) includes a wired circuit board having a metal support layer, an insulating layer, and a conductor layer in that order toward one side in a thickness direction, one thickness side of the metal support layer including an opposing surface that faces the other thickness side of the insulating layer in the thickness direction, and the opposing surface including a joining surface that joins to the other surface and a non-joining surface that does not join to the other surface.

[0007] In this wiring circuit board, the opposing surface of the metal support layer has a non-bonding surface that is not bonded to the other surface of the insulating layer. Since the metal support layer corresponding to the non-bonding surface is not bonded to the insulating layer, warping of the wiring circuit board due to the difference in linear expansion coefficient between the metal support layer and the insulating layer can be suppressed.

[0008] The present invention (2) includes the wired circuit board according to (1), wherein the joining surface is bonded to the other surface via an adhesive layer.

[0009] In this wired circuit board, the force acting between the joining surface and the other surface due to the difference described above can be alleviated by the adhesive layer.

[0010] The present invention (3) includes the wired circuit board according to (1), wherein the insulating layer has a through hole in an area facing the joining surface and the conductor layer, and the joining surface is joined to the other surface via a metal joining material, a part of which is disposed within the through hole.

[0011] According to this wired circuit board, the conductor layer can be electrically connected to the metal support layer via the metal bonding material.

[0012] In addition, since the conductor layer can be fixed to the metal support layer via a metal bonding material, it is possible to ensure accurate relative positioning of the conductor layer and the metal support layer while suppressing warping between the metal support layer including the bonding surface and the insulating layer facing the bonding surface.

[0013] The present invention (4) includes a wired circuit board according to any one of (1) to (3), comprising two end portions arranged at a distance from each other in a first direction and an intermediate portion arranged between the two end portions, each of the two end portions comprising a first metal portion included in the metal support layer and a first insulating portion included in the insulating layer, the intermediate portion comprising a second metal portion included in the metal support layer and a second insulating portion included in the insulating layer, the first metal portion comprising the joining surface, and the second metal portion comprising the non-joining surface.

[0014] Since the intermediate portion can extend long in the first direction, the printed circuit board is prone to warping due to the difference in the linear expansion coefficients described above.

[0015] However, in this wired circuit board, the second metal portion includes a non-joint surface, so that the warping of the intermediate portion caused by the difference in the linear expansion coefficients can be suppressed.

[0016] The present invention (5) includes the wired circuit board according to (4), in which each of the two end portions includes a terminal included in the conductor layer, and the middle portion includes wiring included in the conductor layer.

[0017] The present invention (6) includes the wired circuit board according to (4) or (5), further comprising a second intermediate portion arranged midway between the intermediate portions in the first direction, the second intermediate portion comprising a third metal portion included in the metal support layer and a third insulating portion included in the insulating layer, and the third metal portion including the bonding surface.

[0018] If the intermediate portion is long in the first direction, the second metal portion includes a non-joint surface, and therefore the conductor layer and the insulating layer may not be reliably supported by the metal support layer in the intermediate portion.

[0019] However, in this wired circuit board, the third metal portion includes a bonding surface, and therefore the conductor layer and the third insulating portion are reliably supported by the third metal portion in the second intermediate portion.

[0020] The present invention (7) includes the wired circuit board according to (6), in which the second intermediate portion further includes a second terminal included in the conductor layer.

[0021] The present invention (8) includes the wired circuit board according to (7), in which the third insulating portion has a second through hole that is included in the second terminal when projected in the thickness direction, and the joining surface is joined to the other surface via a second metal joining material, a portion of which is disposed within the second through hole.

[0022] According to this wired circuit board, the second terminal can be electrically connected to the third metal portion via the second metal bonding material.

[0023] In addition, since the second terminal can be fixed to the third metal portion via the second metal bonding material, it is possible to ensure accurate relative positioning between the conductor layer and the third metal portion while suppressing warping between the third metal portion and the third insulating portion. [Effects of the Invention]

[0024] The wired circuit board of the present invention can suppress warpage. [Brief explanation of the drawings]

[0025] [Figure 1] FIG. 2 is a bottom view of one embodiment of the wired circuit board of the present invention. [Figure 2] 2 is a cross-sectional view taken along the line AA of the printed circuit board shown in FIG. [Figure 3] 2 is a cross-sectional view of the printed circuit board shown in FIG. 1 taken along the line BB. [Figure 4] Figures 4A to 4C are diagrams showing steps in manufacturing the wired circuit board shown in Figure 2. Figure 4A shows the first step, Figure 4B shows the second step, and Figure 4C shows the third step. [Figure 5] Figures 5A to 5C are diagrams showing steps in manufacturing the wired circuit board shown in Figure 3. Figure 5A shows the first step, Figure 5B shows the second step, and Figure 5C shows the third step. [Figure 6] FIG. 10 is a cross-sectional view of one end portion of a modified example of a printed circuit board. [Figure 7] FIG. 10 is a bottom view of a modified example of the printed circuit board. [Figure 8] FIG. 8 is a cross-sectional view taken along line AA in FIG. 7. [Figure 9] FIG. 10 is a bottom view of a modified example of the printed circuit board. [Figure 10] FIG. 10 is a cross-sectional view taken along line AA in FIG. 9. [Figure 11] FIG. 10 is a bottom view of a modified example of the printed circuit board. [Figure 12] FIG. 12 is a cross-sectional view taken along line AA in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0026] 1. Wired circuit board One embodiment of the wired circuit board of the present invention will be described with reference to Figs. 1 to 3. As shown in Fig. 1, the wired circuit board 1 extends in a first direction and a second direction. The first direction is perpendicular to the thickness direction. The second direction is perpendicular to the thickness direction and the first direction. The wired circuit board 1 has a generally rectangular shape in a plan view. Specifically, the wired circuit board 1 is long in the first direction. The wired circuit board 1 has two end portions 2A, 2B and a middle portion 3.

[0027] 1.1 Two ends 2A, 2B The two ends 2A, 2B are arranged at a distance from each other in the first direction. Specifically, one end 2A is arranged at one end in the first direction of the wired circuit board 1. The other end 2B is arranged at the other end in the first direction of the wired circuit board 1. Each of the two ends 2A, 2B has a generally rectangular shape in a plan view extending in the second direction.

[0028] 1.2 Middle section 3 The intermediate portion 3 is disposed between the two end portions 2A, 2B. The intermediate portion 3 connects the two end portions 2A, 2B in the first direction. The intermediate portion 3 has a generally rectangular shape in a plan view extending in the first direction. The ratio of the length of the intermediate portion 3 in the first direction to the length of each of the two end portions 2A, 2B in the first direction is, for example, 2 or more, preferably 5 or more, more preferably 10 or more, even more preferably 100 or more, particularly preferably 1,000 or more, and is, for example, 100,000 or less.

[0029] 1.3 Layer structure of printed circuit board 1 2 and 3, the wired circuit board 1 includes, in order toward one side in the thickness direction, a metal support layer 4, a base insulating layer 5 as an example of an insulating layer, a conductor layer 6, and a cover insulating layer 7. The wired circuit board 1 further includes an adhesive layer 8 (see FIG. 3).

[0030] 1.3.1 Metal support layer 4 The metal support layer 4 forms the other surface in the thickness direction of the wired circuit board 1. As shown in FIGS. 1 to 3, the metal support layer 4 is disposed across the two end portions 2A, 2B and the middle portion 3. The metal support layer 4 includes a first metal portion 41 and a second metal portion 42.

[0031] 1.3.1.2 First metal part 41 The first metal portions 41 are disposed at the two ends 2A and 2B, respectively. Each of the two first metal portions 41 extends in the second direction. Each of the two first metal portions 41 has a generally rectangular shape in plan view.

[0032] 1.3.1.3 Second metal part 42 The second metal portion 42 is disposed in the intermediate portion 3. A plurality of second metal portions 42 (two in this embodiment) are disposed at intervals from each other in the second direction. Each of the plurality of second metal portions 42 connects two first metal portions 41.

[0033] The length in the second direction of each of the multiple second metal portions 42 is shorter than the length in the second direction of the first metal portion 41. Specifically, the ratio of the length in the second direction of each of the multiple second metal portions 42 to the length in the second direction of the first metal portion 41 is, for example, 0.7 or less, preferably 0.5 or less, more preferably 0.2 or less, even more preferably 0.1 or less, and is, for example, 0.001 or more.

[0034] 1.3.1.4 One surface 43 of the metal support layer 4 The metal support layer 4 has one surface 43 in the thickness direction. The one surface 43 includes an opposing surface 44. The opposing surface 44 will be described later.

[0035] The metal supporting layer 4 has a thickness of, for example, 30 μm or more, preferably 50 μm or more, preferably 75 μm or more, more preferably 100 μm or more. The metal supporting layer 4 has a thickness of, for example, 1000 μm or less, preferably 500 μm or less.

[0036] The material of the metal support layer 4 is a metal. Examples of metals include metal elements classified into Groups 1 to 16 of the Periodic Table (IUPAC, 2018) and alloys containing two or more of these metal elements. The metal may be either a transition metal or a typical metal. More specifically, examples of metals include Group 2 metal elements, Group 4 metal elements, Group 5 metal elements, Group 6 metal elements, Group 7 metal elements, Group 8 metal elements, Group 9 metal elements, Group 10 metal elements, Group 11 metal elements, Group 12 metal elements, Group 13 metal elements, and Group 14 metal elements. Examples of Group 2 metal elements include calcium. Examples of Group 4 metal elements include titanium and zirconium. Examples of Group 5 metal elements include vanadium. Examples of Group 6 metal elements include chromium, molybdenum, and tungsten. Examples of Group 7 metal elements include manganese. Examples of Group 8 metal elements include iron. Examples of Group 9 metal elements include cobalt. Examples of Group 10 metal elements include nickel and platinum. Examples of Group 11 metal elements include copper, silver, and gold. Examples of Group 12 metal elements include zinc. Examples of Group 13 metal elements include aluminum and gallium. Examples of Group 14 metal elements include germanium and tin. These can be used alone or in combination. As the metal, preferred are Group 11 metal elements, more preferably copper and copper alloys.

[0037] The linear expansion coefficient of the metal support layer 4 is, for example, 45×10 -6 / K or less, preferably 35×10 -6 / K or less, more preferably 30×10 -6 / K or less, and for example, 0.1 × 10 -6 / K or more. The linear expansion coefficient of the metal support layer 4 is measured based on JIS Z 2285 (2003).

[0038] 1.3.2 Base Insulation Layer 5 The base insulating layer 5 is disposed on the other side in the thickness direction of the metal support layer 4. The base insulating layer 5 is disposed across the two end portions 2A, 2B and the intermediate portion 3. Specifically, the base insulating layer 5 has a generally rectangular shape in a plan view. The base insulating layer 5 has a flat band shape extending in the first direction. The base insulating layer 5 extends continuously in the first direction. The base insulating layer 5 has a first insulating portion 51 and a second insulating portion 52.

[0039] 1.3.2.1 First insulating part 51 The first insulating portion 51 is included in the two end portions 2A and 2B. The first insulating portion 51 has a generally rectangular shape in a plan view. The first insulating portion 51 is arranged on one side in the thickness direction of the first metal portion 41. Specifically, the first insulating portion 51 includes the first metal portion 41 when projected in the thickness direction. In more detail, both end edges in the second direction and one end edge in the first direction of the first insulating portion 51 arranged at one end portion 2A do not overlap with the first metal portion 41 when projected in the thickness direction. Both end edges in the second direction and the other end edge in the first direction of the first insulating portion 51 arranged at the other end portion 2B do not overlap with the first metal portion 41 when projected in the thickness direction.

[0040] 1.3.2.2 Second insulating part 52 The second insulating portion 52 is included in the intermediate portion 3. The second insulating portion 52 is arranged on one side in the thickness direction of the second metal portion 42. The second insulating portion 52 has a generally rectangular shape in a plan view extending in the first direction. When projected in the thickness direction, the second insulating portion 52 is arranged between the multiple second metal portions 42, on the outside of the second metal portion 42 arranged on the outermost side in the second direction, and also on the outside of the second metal portion 42 arranged on the outermost side in the second direction.

[0041] The insulating base layer 5 has a thickness of, for example, 1 μm or more, or preferably 5 μm or more, and for example, 100 μm or less, or preferably 50 μm or less.

[0042] An insulating resin may be used as the material for the insulating base layer 5. Examples of the insulating resin include polyimide, maleimide, epoxy resin, polybenzoxazole, and polyester.

[0043] The linear expansion coefficient of the insulating base layer 5 is, for example, larger than the linear expansion coefficient of the metal support layer 4. The linear expansion coefficient of the insulating base layer 5 is, for example, 10×10 -6 / K or more, preferably 15 × 10 -6 / K or more, and for example, 200 × 10 -6 The difference between the linear expansion coefficient of the metal support layer 4 and the linear expansion coefficient of the base insulating layer 5 is, for example, 1×10 -6 / K or more, preferably 2 × 10 -6 / K or more, more preferably 5×10 -6 / K or more, and for example, 100 × 10 -6 / K or less. The linear expansion coefficient of the base insulating layer 5 is measured based on JISK 7197 (2012).

[0044] 1.3.2.3 One surface 53 and the other surface 54 of the base insulating layer 5 The insulating base layer 5 has one surface 53 and the other surface 54 in the thickness direction.

[0045] 1.3.3 Conductor layer 6 The conductor layer 6 is disposed across the two end portions 2A, 2B and the intermediate portion 3. The conductor layer 6 is disposed on one surface 53 in the thickness direction of the base insulating layer 5. The conductor layer 6 includes a plurality of one-end terminals 61A, a plurality of other-end terminals 61B, and a plurality of wirings 62.

[0046] 1.3.3.1 Multiple one-end terminals 61A The plurality of one-end terminals 61A are included in the one end 2A. When projected in the thickness direction, the plurality of one-end terminals 61A are included in the first metal portion 41 at the one end 2A. The plurality of one-end terminals 61A are spaced apart from one another in the second direction. Each of the plurality of one-end terminals 61A has, for example, a generally rectangular shape (a square land shape) in plan view.

[0047] 1.3.3.2 Multiple other-end terminals 61B The multiple other end terminals 61B are included in the other end 2B. When projected in the thickness direction, the multiple other end terminals 61B are included in the first metal portion 41 at the other end 2B. The multiple other end terminals 61B are spaced apart from one another in the second direction.

[0048] 1.3.3.3 Multiple Wires62 The plurality of wirings 62 are included in the intermediate portion 3. When projected in the thickness direction, the plurality of wirings 62 are included in the second metal portion 42. Each of the plurality of wirings 62 connects each of the plurality of one-end side terminals 61A to each of the plurality of other-end side terminals 61B.

[0049] The thickness of the conductor layer 6 is, for example, 1 μm or more, or preferably 5 μm or more, and for example, 50 μm or less, or preferably 30 μm or less.

[0050] Examples of materials for the conductor layer 6 include conductors, such as copper, silver, gold, iron, aluminum, chromium, and alloys thereof. Copper is preferred from the viewpoint of obtaining good electrical properties.

[0051] 1.3.4 Cover insulating layer 7 As shown in FIG. 2, the cover insulating layer 7 is included in the intermediate portion 3. The cover insulating layer 7 is disposed on one surface 53 in the thickness direction of the base insulating layer 5 so as to cover the plurality of wirings 62. The thickness of the cover insulating layer 7 is, for example, 1 μm or more, preferably 5 μm or more, and for example, 100 μm or less, preferably 50 μm or less. Examples of materials for the cover insulating layer 7 include insulating resins. Examples of insulating resins include polyimide, maleimide, epoxy resin, polybenzoxazole, and polyester. The insulating resin also includes solder resist.

[0052] 1.3.5 Adhesive layer 8 As shown in FIG. 3, the adhesive layer 8 is disposed on a joining surface 45, which will be described next. Examples of materials for the adhesive layer 8 include adhesive compositions. Examples of adhesive compositions include curable adhesive compositions and thermoplastic adhesive compositions. The type of adhesive composition is not limited. If the adhesive composition is a curable adhesive composition, the adhesive layer 8 will be made of a cured product of the curable adhesive composition. Examples of adhesive compositions include epoxy adhesive compositions, silicone adhesive compositions, urethane adhesive compositions, and acrylic adhesive compositions.

[0053] 1.4 Opposite faces 44 One surface 43 in the thickness direction of the metal support layer 4 includes an opposing surface 44 that faces the other surface 54 in the thickness direction of the insulating base layer 5. In this embodiment, (the entirety of) the one surface 43 of the metal support layer 4 is the opposing surface 44. The opposing surface 44 has a joining surface 45 and a non-joining surface 46.

[0054] 1.4.1 Joint surface 45 The joining surface 45 is included in the two first metal portions 41. The joining surface 45 is joined to the other surface 54 in the thickness direction of the first insulating portion 51. In this embodiment, the joining surface 45 is bonded to the other surface 54 in the thickness direction of the first insulating portion 51 via an adhesive layer 8. Note that "bonding" includes pressure-sensitive bonding (adhesion). The adhesive layer 8 contacts the joining surface 45 and the other surface 54.

[0055] The bonding strength (adhesion) of the bonding surface 45 to the other surface 54 is, for example, 0.1 N / mm or more, preferably 0.3 N / mm or more, more preferably 0.5 N / mm or more, and for example, 10 N / mm or less. The bonding strength is measured by a 180-degree peel test.

[0056] 1.4.2 Non-bonding surface46 As shown in FIG. 2 , the non-bonding surface 46 is included in the second metal portion 42. The non-bonding surface 46 is not bonded to the other surface 54 of the second insulating portion 52 in the thickness direction. Specifically, the non-bonding surface 46 is movable (slidable) relative to the other surface 54 of the second insulating portion 52 in the thickness direction. In this embodiment, the non-bonding surface 46 is spaced apart from the other surface 54 of the second insulating portion 52 in the thickness direction. Although not shown, the non-bonding surface 46 may be in contact with the other surface 54 of the second insulating portion 52.

[0057] 2. Manufacturing method of the wired circuit board 1 A method for manufacturing the wired circuit board 1 will be described with reference to Figures 4A to 5C. The method for manufacturing the wired circuit board 1 includes a first step, a second step, and a third step.

[0058] 2.1 First step 4A and 5A, the first step is to prepare a circuit laminate material 10. The circuit laminate material 10 includes, in order toward one side in the thickness direction, an insulating base layer 5, a conductor layer 6, and an insulating cover layer 7.

[0059] To prepare the circuit laminate 10, first, a two-layer substrate (not shown) is prepared, which includes a base insulating layer 5 and a conductor plate (not shown) in that order in the thickness direction. Next, the conductor plate of the two-layer substrate is formed into a conductor layer 6, for example, by a subtractive method, and then a cover insulating layer 7 is formed.

[0060] 2.2 Second process As shown in FIGS. 4B and 5B, a metal plate 40 is placed on the circuit laminate material 10. The metal plate 40 is the metal support layer 4 before its outer shape is processed. As shown in FIG. 5B, in the second step, an adhesive layer 8 is placed on the other side 54 of the first insulating portion 51 of the circuit laminate material 10 and / or on the joining surface 45 of the metal plate 40, and then the other side 54 and the joining surface 45 are bonded together (adhered) via the adhesive layer 8. On the other hand, as shown in FIG. 4B, the other side 54 of the second insulating portion 52 of the circuit laminate material 10 faces the non-joining surface 46 of the metal plate 40 at a distance in the thickness direction. This produces a partially bonded laminate 11 including the joining surface 45 and the non-joining surface 46.

[0061] The partially adhesive laminate 11 includes, in a portion corresponding to the one end 2A, a metal plate 40, an adhesive layer 8, a first insulating portion 51, and a one-end terminal 61A, arranged in that order toward one side in the thickness direction. The partially adhesive laminate 11 includes, in a portion corresponding to the other end 2B, a metal plate 40, an adhesive layer 8, a first insulating portion 51, and a one-end terminal 61B, arranged in that order toward one side in the thickness direction.

[0062] 4B , the partially adhesive laminate 11 includes, in a portion corresponding to the intermediate portion 3, a metal plate 40, a second insulating portion 52, wiring 62, and a cover insulating layer 7, which are arranged in this order toward one side in the thickness direction. The partially adhesive laminate 11 does not include an adhesive layer 8 in a portion corresponding to the intermediate portion 3.

[0063] 2.3 Third step As shown in FIGS. 4C and 5C, a metal support layer 4 is formed from a metal plate 40. For example, the metal plate 40 is shaped by etching or the like. This forms a metal support layer 4 including a first metal portion 41 and a second metal portion 42. This completes the manufacture of a wired circuit board 1.

[0064] 3. Effects of one embodiment 2, in this wired circuit board 1, the opposing surface 44 of the metal support layer 4 has a non-bonding surface 46 that is not bonded to the other surface 54 of the base insulating layer 5. The metal support layer 4 (specifically, the second metal portion 42) corresponding to the non-bonding surface 46 is not bonded to the base insulating layer 5, and therefore can move (slide) (shift) relative to the base insulating layer 5. Therefore, warping of the wired circuit board 1 caused by the difference between the linear expansion coefficients of the metal support layer 4 and the base insulating layer 5 can be suppressed.

[0065] In this wired circuit board 1, the adhesive layer 8 can reduce the force acting between the joining surface 45 and the other surface 54 due to the difference described above.

[0066] Furthermore, as shown in FIG. 1, the intermediate portion 3 can extend long in the first direction, and therefore warping of the intermediate portion 3 in the first direction due to the difference in the linear expansion coefficients described above is likely to occur.

[0067] However, in this wired circuit board 1, as described above, the second metal portion 42 includes the non-joint surface 46, and therefore, warping of the wired circuit board 1 caused by the difference described above can be suppressed.

[0068] 4. Variations In the following modifications, the same components and steps as those in the above-described embodiment are denoted by the same reference numerals, and detailed descriptions thereof will be omitted. Furthermore, each modification can achieve the same effects as those in the above-described embodiment unless otherwise specified. Furthermore, the embodiment and modifications can be combined as appropriate.

[0069] 6, the joining surface 45 of the first metal portion 41 may be in contact with and joined to the other surface 54 of the first insulating portion 51 without the adhesive layer 8. This joining includes, for example, "adhesion" between the other surface 54 of the first insulating portion 51 of the base insulating layer 5, which is produced by applying the material composition of the base insulating layer 5 to the joining surface 45, and the joining surface 45 of the first metal portion 41. The adhesive strength is the same as the bonding strength described above.

[0070] On the other hand, the joining does not include “stacking” of the insulating sheet onto the opposing surface 44 of the first metal portion 41 .

[0071] In the embodiment, the entire one surface 43 of the intermediate portion 3 is the joining surface 45, but the one surface 43 may include the joining surface 45 and the non-joint surface .

[0072] 7, the wired circuit board 1 further includes a second intermediate portion 31. The second intermediate portion 31 is disposed midway between the intermediate portions 3 in the first direction. The second intermediate portion 31 extends in the second direction.

[0073] As shown in FIG. 8, the second intermediate portion 31 includes a third metal portion 47, an adhesive layer 8, a third insulating portion 55, wiring 62, and a cover insulating layer .

[0074] The third metal portion 47 is included in the metal support layer 4. The third metal portion 47 has a generally rectangular shape in plan view that extends in the second direction.

[0075] The length in the second direction of each of the multiple second metal portions 42 is shorter than the length in the second direction of the third metal portion 47. Specifically, the ratio of the length in the second direction of each of the multiple second metal portions 42 to the length in the second direction of the third metal portion 47 is, for example, 0.7 or less, preferably 0.5 or less, more preferably 0.2 or less, even more preferably 0.1 or less, and is, for example, 0.001 or more.

[0076] When projected in the thickness direction, the third insulating portion 55 includes the above-described third metal portion 47. The third insulating portion 55 is included in the base insulating layer 5. One surface 43 in the thickness direction of the third metal portion 47 includes a bonding surface 45. The bonding surface 45 is bonded to the other surface 54 in the thickness direction of the third insulating portion 55 via an adhesive layer 8.

[0077] In one embodiment, when the intermediate portion 3 becomes longer in the first direction, the second metal portion 42 includes a non-joint surface 46, as shown in Figure 2, and therefore the conductor layer 6 and the base insulating layer 5 are not reliably supported by the metal support layer 4 in the intermediate portion 3.

[0078] However, in this modified wired circuit board 1, as shown in Figure 8, the third metal portion 47 includes a bonding surface 45, so that the conductor layer 6 and the third insulating portion 55 are reliably supported by the third metal portion 47 in the second intermediate portion 31.

[0079] There may be one or more second intermediate portions 31. When there are multiple second intermediate portions 31, the multiple second intermediate portions 31 are arranged at intervals from each other in the first direction.

[0080] 9 and 10 , the base insulating layer 5 has through holes 48 in a region facing the joint surface 45, specifically, in the first insulating portion 51 disposed at the one end 2A. A plurality of through holes 48 are provided corresponding to the plurality of one-end terminals 61A. In this modification, the one-end terminals 61A are ground terminals. Each of the plurality of through holes 48 is included in a corresponding one of the plurality of one-end terminals 61A in plan view.

[0081] The wired circuit board 1 of this modified example includes a metal bonding material 81 instead of the adhesive layer 8. A plurality of the metal bonding materials 81 are provided corresponding to the plurality of through holes 48. A portion of each of the plurality of metal bonding materials 81 is disposed within the through hole 48, and the remainder is disposed between the bonding surface 45 of the first metal portion 41 and the other surface 54 of the first insulating portion 51. In this modified example, the metal bonding material 81 is, for example, solder. The bonding surface 45 is bonded to the other surface 54 via the metal bonding material 81. The metal bonding material 81 metal-bonds the other surface in the thickness direction of the one-end terminal 61A to the bonding surface 45 of the first metal portion 41. In this way, the metal bonding material 81 electrically connects the first metal portion 41 and the plurality of one-end terminals 61A.

[0082] According to this wired circuit board 1, the conductor layer 6 can be electrically connected to the metal support layer 4 via the metal bonding material 81. Specifically, the plurality of one-end terminals 61A are connected to the metal support layer 4 as a ground.

[0083] In addition, since the conductor layer 6 can be fixed to the metal support layer 4 via the metal bonding material 81, it is possible to ensure accurate relative positioning of the conductor layer 6 and the metal support layer 4 while suppressing warping between the metal support layer 4 including the bonding surface 45 and the base insulating layer 5 facing the bonding surface 45.

[0084] 11 and 12, the second intermediate portion 31 includes a second terminal 63, which is an example of the other end side terminal included in the conductor layer 6. A plurality of second terminals 63 are provided corresponding to the plurality of wirings 62.

[0085] The third insulating portion 55 has a second through hole 58. A plurality of second through holes 58 are provided corresponding to the plurality of second terminals 63.

[0086] The bonding surface 45 of the third metal portion 47 is bonded to the other surface 54 of the third insulating portion 55 via a second metal bonding material 82.

[0087] According to this wired circuit board 1, the second terminal 63 can be electrically connected to the third metal portion 47 via the second metal bonding material 82. Specifically, the second terminal 63 is connected to the third metal portion 47 as a ground.

[0088] In addition, since the second terminal 63 can be fixed to the third metal portion 47 via the second metal bonding material 82, it is possible to ensure accurate relative positioning between the conductor layer 6 and the third metal portion 47 while suppressing warping between the third metal portion 47 and the third insulating portion 55.

[0089] In the manufacturing method of the embodiment, a subtractive method is exemplified as a method for forming the conductor layer 6. However, in a modified example, an additive method can also be exemplified as a method for forming the conductor layer 6. [Explanation of symbols]

[0090] 1 Wiring circuit board 2A One end 2B Other end 3. Middle section 4 Metal support layer 5 Base insulation layer 6 Conductor Layer 8 Adhesive layer 31 Second Intermediate Section 41 1st metal part 42 Second metal part 43 One side 44 Opposite Surface 45 Joint surface 46 Non-bonded surface 47 Third metal part 48 through holes 51 First insulation section 52 Second insulating section 53 One side 54 Other side 55 Third insulation section 58 Second through hole 61A One end terminal 61B Other end terminal 62 Wiring 63 2nd terminal 81 Metal bonding materials 82 Second metal bonding material

Claims

1. a metal support layer, an insulating layer, and a conductor layer in this order toward one side in a thickness direction; one surface in a thickness direction of the metal support layer includes an opposing surface that faces the other surface in the thickness direction of the insulating layer, The opposing surface is a joining surface that joins with the other surface; a non-bonding surface that is not bonded to the other surface.

2. The printed circuit board according to claim 1 , wherein the joining surface is bonded to the other surface via an adhesive layer.

3. the insulating layer has through holes in a region facing the bonding surface and the conductor layer, The printed circuit board according to claim 1 , wherein the joining surface is joined to the other surface via a metal joining material, a part of which is disposed in the through hole.

4. two ends spaced apart from each other in a first direction; an intermediate portion disposed between the two end portions; Each of the two ends has: a first metal portion included in the metal support layer; a first insulating portion included in the insulating layer, The intermediate portion is a second metal portion included in the metal support layer; a second insulating portion included in the insulating layer, the first metal portion includes the joining surface, The wired circuit board according to claim 1 , wherein the second metal portion includes the non-bonding surface.

5. each of the two ends includes a terminal included in the conductor layer; The printed circuit board according to claim 4 , wherein the intermediate portion comprises wiring included in the conductor layer.

6. a second intermediate portion disposed intermediately of the intermediate portion in the first direction; The second intermediate portion is a third metal portion included in the metal support layer; a third insulating portion included in the insulating layer, The wired circuit board according to claim 4 or 5, wherein the third metal portion includes the bonding surface.

7. The printed circuit board according to claim 6 , wherein the second intermediate portion further comprises a second terminal included in the conductor layer.

8. the third insulating portion has a second through hole that is included in the second terminal when projected in the thickness direction; The printed circuit board according to claim 7 , wherein the joining surface is joined to the other surface via a second metal joining material, a part of which is disposed in the second through hole.

Images