Wiring circuit board, and method for manufacturing wiring circuit board

Abstract

To provide a wiring circuit board capable of reducing the impedance difference between terminals and wiring without opening a metal layer, and a method for manufacturing the wiring circuit board.SOLUTION: A wiring circuit board 1 comprises a metal layer 2, a base insulating layer 3, and circuit patterns 4. The circuit patterns 4 include a terminal 41 and a wiring 42 connected to the terminal 41. The wiring 42 has a connection portion 420 connected to the terminal 41. The width W1 of terminal 41 is wider than the width W2 of connection portion 420. In the thickness direction, the distance D1 between at least a portion of terminal 41 and metal layer 2 is longer than the distance D2 between at least a portion of connection portion 420 and metal layer 2.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a wired circuit board and a method for manufacturing the wired circuit board. [Background technology]

[0002] Conventionally, a wired circuit board has been known that includes a metal supporting board, an insulating layer, and a conductor layer. The conductor layer includes a terminal portion and a wiring portion connected to the terminal portion (see, for example, Patent Document 1 below). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-111045 Summary of the Invention [Problem to be solved by the invention]

[0004] According to the wired circuit board described in Patent Document 1, openings facing the terminal portions are provided in the metal supporting board, thereby adjusting the characteristic impedance of the terminal portions.

[0005] In this regard, when the terminal portion is small or the metal supporting board is thick, it may be difficult to open the metal supporting board.

[0006] The present invention provides a wired circuit board that can reduce the difference in impedance between a terminal and a wiring without forming an opening in a metal layer, and a method for manufacturing the wired circuit board. [Means for solving the problem]

[0007] The present invention [1] includes a wired circuit board comprising: a circuit pattern having a metal layer, a terminal, and wiring connected to the terminal; and an insulating layer disposed between the metal layer and the circuit pattern in the thickness direction of the metal layer, the wiring having a connection portion connected to the terminal, the width of the terminal being wider than the width of the connection portion, and the distance between at least a portion of the terminal and the metal layer in the thickness direction being longer than the distance between at least a portion of the connection portion and the metal layer.

[0008] With this configuration, the distance between at least a portion of the terminal and the metal layer in the thickness direction is longer than the distance between at least a portion of the connection portion of the wiring and the metal layer.

[0009] Therefore, the impedance of the terminal can be increased to approach the impedance of the connection portion.

[0010] As a result, the difference in impedance between the terminal and the wiring can be reduced without opening the metal layer.

[0011] The present invention [2] includes the wired circuit board of the above [1], in which the distance between all of the terminals and the metal layer is longer than the distance between at least a part of the connection portion and the metal layer.

[0012] With this configuration, the impedance of all the terminals can be increased to approach the impedance of the connection portion.

[0013] Therefore, the difference in impedance between the terminal and the wiring can be further reduced.

[0014] The present invention [3] includes the wired circuit board of the above [1], in which the distance between all of the terminals and the metal layer is longer than the distance between all of the connection portions and the metal layer.

[0015] With this configuration, the difference in impedance between all of the terminals and all of the connecting portions can be reduced.

[0016] Therefore, the difference in impedance between the terminal and the wiring can be further reduced.

[0017] The present invention [4] includes the wired circuit board of any one of the above [1] to [3], wherein the insulating layer has a first portion having a first thickness and a second portion having a second thickness that is thicker than the first thickness, at least a part of the connection portion is disposed on the first portion, and at least a part of the terminal is disposed on the second portion.

[0018] According to this configuration, the second portion of the insulating layer makes it possible to make the distance between at least a portion of the terminal and the metal layer longer than the distance between at least a portion of the connection portion and the metal layer.

[0019] The present invention [5] includes the wired circuit board according to the above [4], in which all of the terminals are disposed on the second portion.

[0020] With this configuration, the impedance of all the terminals can be increased to approach the impedance of the connection portion.

[0021] Therefore, the difference in impedance between the terminal and the wiring can be further reduced.

[0022] The present invention [6] includes the wired circuit board according to the above [4] or [5], in which the entire connecting portion is disposed on the first portion.

[0023] With this configuration, the impedance of the terminal can be increased to approach the impedance of the entire connecting portion.

[0024] As a result, the difference in impedance between the terminal and the wiring can be further reduced.

[0025] The present invention [7] includes the wired circuit board of any one of the above [4] to [6], wherein the second part has a first layer that is united with the first part and a second layer that is disposed on the first layer.

[0026] The present invention [8] includes the wired circuit board according to any one of the above [4] to [6], wherein the entire second portion is unitary with the first portion.

[0027] The present invention [9] includes the wired circuit board of any one of the above [1] to [8], wherein the metal layer has a first metal layer and a second metal layer disposed between the first metal layer and the insulating layer in the thickness direction.

[0028] The present invention

[10] includes the wired circuit board according to the above [9], wherein the second metal layer has a through hole that overlaps with the terminal in the thickness direction.

[0029] The present invention

[11] includes the wired circuit board of any one of the above [1] to

[10] , wherein the metal layer overlaps the terminal in the thickness direction and has a recess that is recessed in a direction away from the terminal in the thickness direction.

[0030] According to this configuration, the recess in the metal layer makes it possible to make the distance between at least a portion of the terminal and the metal layer longer than the distance between at least a portion of the connection portion and the metal layer.

[0031] The present invention

[12] is a method for manufacturing a wired circuit board according to the above [7], comprising a first insulating layer forming step of forming the first portion and the first layer of the second portion on the metal layer, a second insulating layer forming step of forming the second layer of the second portion on the first layer, and a patterning step of forming the circuit pattern on the insulating layer.

[0032] According to this configuration, the first portion and the second portion can be easily formed in the insulating layer through the first insulating layer forming step and the second insulating layer forming step.

[0033] The present invention

[13] is a method for manufacturing a wired circuit board according to the above [8], which includes an insulating layer forming step of forming the insulating layer on the metal layer, and a patterning step of forming the circuit pattern on the insulating layer, and in the insulating layer forming step, the first portion and the second portion are formed in the insulating layer by gradation exposure or etching.

[0034] According to this configuration, the first portion and the second portion can be easily formed in the insulating layer by gradation exposure or etching.

[0035] The present invention

[14] is a method for manufacturing a wired circuit board according to the above

[10] , comprising a metal layer forming step of forming the second metal layer having the through hole on the first metal layer, an insulating layer forming step of forming the insulating layer on the second metal layer so that the insulating layer fills the through hole, and a patterning step of forming the circuit pattern on the insulating layer.

[0036] According to this configuration, by forming the second metal layer having the through-holes on the first metal layer, it is possible to easily form the metal layer having the recesses.

[0037] The present invention

[15] is a method for manufacturing a wired circuit board according to the above

[10] , comprising a metal layer forming step of forming the second metal layer on the first metal layer, a through hole forming step of etching the second metal layer to form the through hole in the second metal layer, an insulating layer forming step of forming the insulating layer on the second metal layer so that the insulating layer fills the through hole, and a patterning step of forming the circuit pattern on the insulating layer.

[0038] According to this configuration, by etching the second metal layer, recesses can be easily formed in the metal layer.

[0039] The present invention

[16] includes a method for manufacturing a wired circuit board according to the above

[11] , which includes a recess forming step of etching the metal layer to form the recess in the metal layer, an insulating layer forming step of forming the insulating layer on the metal layer so that the insulating layer fills the recess, and a patterning step of forming the circuit pattern on the insulating layer.

[0040] According to this configuration, the recesses can be easily formed in the metal layer by etching the metal layer. [Effects of the Invention]

[0041] According to the wired circuit board of the present invention, the difference in impedance between the terminals and the wiring can be reduced without forming openings in the metal layer.

[0042] According to the method for producing a wired circuit board of the present invention, the above-mentioned wired circuit board can be easily produced. [Brief explanation of the drawings]

[0043] [Figure 1] Fig. 1A is a perspective view of a printed circuit board according to a first embodiment, and Fig. 1B is a plan view of the printed circuit board shown in Fig. 1A. [Figure 2] FIG. 2 is a cross-sectional view of the printed circuit board shown in FIG. 1B taken along line AA. [Figure 3] 3A to 3C are process diagrams showing a method for manufacturing the wired circuit board shown in FIG. 2, in which FIG. 3A shows a metal layer forming process, FIG. 3B shows a base insulating layer forming process, and FIG. 3C shows a patterning process. [Figure 4] FIG. 4 shows a wired circuit board according to a modified example (2) of the first embodiment. [Figure 5] FIG. 5A shows a first insulating layer forming step in the method for producing the wired circuit board shown in FIG. 4, and FIG. 5B shows a second insulating layer forming step. [Figure 6] FIG. 6 shows a wired circuit board according to a modified example (3) of the first embodiment. [Figure 7]Fig. 7A is a plan view of a wired circuit board according to a fourth modification of the first embodiment, and Fig. 7B is a cross-sectional view taken along line BB of the wired circuit board shown in Fig. 7A. [Figure 8] Fig. 8A is a plan view of a wired circuit board according to a modified example (5) of the first embodiment, and Fig. 8B is a cross-sectional view taken along line CC of the wired circuit board shown in Fig. 8A. [Figure 9] Fig. 9A is a plan view of a wired circuit board according to a sixth modified example of the first embodiment, and Fig. 9B is a DD cross-sectional view of the wired circuit board shown in Fig. 9A. [Figure 10] Fig. 10A is a perspective view of a printed circuit board according to a second embodiment, and Fig. 10B is a plan view of the printed circuit board shown in Fig. 10A. [Figure 11] FIG. 11 is an E-E cross-sectional view of the printed circuit board shown in FIG. 10B. [Figure 12] Figures 12A to 12D are process diagrams showing a method for manufacturing the wired circuit board shown in Figure 11, where Figure 12A shows a metal layer formation process, Figure 12B shows a through hole formation process, Figure 12C shows a base insulating layer formation process, and Figure 12D shows a pattern process. [Figure 13] Figures 13A and 13B show the metal layer formation process of variant (1) of the second embodiment, where Figure 13A shows the process of forming a second metal layer while the area where the through hole will be formed is covered with plating resist, and Figure 13B shows the process of peeling off the plating resist. [Figure 14] FIG. 14 shows a wired circuit board according to a modified example (2) of the second embodiment. [Figure 15] 15A to 15C are process diagrams showing a method for manufacturing the wired circuit board shown in FIG. 14, in which FIG. 15A shows a recess formation process, FIG. 15B shows a base insulating layer formation process, and FIG. 15C shows a pattern process. [Figure 16] Fig. 16A shows a wired circuit board according to a modified example (3) of the second embodiment, and Fig. 16B shows a wired circuit board according to a modified example (4) of the second embodiment. [Figure 17] Fig. 17A is a plan view of a wired circuit board according to a modified example (5) of the second embodiment, and Fig. 17B is an FF cross-sectional view of the wired circuit board shown in Fig. 17A. DETAILED DESCRIPTION OF THE INVENTION

[0044] 1. First embodiment 1A and 1B, the wired circuit board 1 of the first embodiment extends in a first direction and a second direction. The second direction is perpendicular to the first direction. The shape of the wired circuit board 1 is not limited to that of the first embodiment. The wired circuit board 1 may be a flexible wired circuit board or a circuit-equipped suspension board.

[0045] As shown in FIG. 2, the wired circuit board 1 includes a metal layer 2, a base insulating layer 3 as an example of an insulating layer, a circuit pattern 4, and a cover insulating layer 5.

[0046] (1) Metal layer The metal layer 2 supports the base insulating layer 3, the circuit pattern 4, and the cover insulating layer 5. The metal layer 2 may have multiple layers made of different metals. In the first embodiment, the metal layer 2 has a first metal layer 21 and a second metal layer 22. In the first embodiment, the metal layer 2 does not have to have the second metal layer 22.

[0047] The first metal layer 21 is disposed apart in the thickness direction from the insulating base layer 3. The thickness direction is perpendicular to the first direction and the second direction. Examples of materials for the first metal layer 21 include stainless steel and copper alloys.

[0048] The second metal layer 22 is disposed on one side of the first metal layer 21 in the thickness direction. The second metal layer 22 is disposed on one surface of the first metal layer 21 in the thickness direction. The second metal layer 22 is disposed between the first metal layer 21 and the insulating base layer 3 in the thickness direction. The material of the second metal layer 22 may be the same as or different from the material of the first metal layer 21. An example of the material of the second metal layer 22 is copper. The thickness of the second metal layer 22 may be thinner than the thickness of the first metal layer 21.

[0049] (2) Base insulation layer The base insulating layer 3 is disposed on one side of the second metal layer 22 in the thickness direction. The base insulating layer 3 is disposed on one surface of the second metal layer 22 in the thickness direction. The base insulating layer 3 is disposed between the second metal layer 22 and the circuit pattern 4 in the thickness direction. In other words, the base insulating layer 3 is disposed between the metal layer 2 and the circuit pattern 4 in the thickness direction. The base insulating layer 3 insulates the second metal layer 22 from the circuit pattern 4. The base insulating layer 3 is made of a resin. Examples of resins include polyimide, maleimide, epoxy resin, polybenzoxazole, and polyester. The base insulating layer 3 has a first portion 31 and a second portion 32. The first portion 31 has a first thickness T1. The second portion 32 is disposed on one side of the first portion 31 in the second direction. The second portion 32 is continuous with the first portion 31. The entire second portion 32 is united with the first portion 31. In other words, the entire second portion 32 is made from the same material as the first portion 31 and is integral with the first portion 31. There is no interface between the first portion 31 and the second portion 32. The second portion 32 has a second thickness T2. The second thickness T2 is thicker than the first thickness T1.

[0050] (3) Circuit pattern The circuit pattern 4 is disposed on one side of the base insulating layer 3 in the thickness direction. The circuit pattern 4 is disposed on one surface of the base insulating layer 3 in the thickness direction. The circuit pattern 4 is disposed on the opposite side of the base insulating layer 3 from the metal layer 2 in the thickness direction. The circuit pattern 4 is made of a metal. Examples of metals include copper, silver, gold, iron, aluminum, chromium, and alloys thereof. Copper is preferable from the viewpoint of obtaining good electrical properties. The shape of the circuit pattern 4 is not limited.

[0051] As shown in FIGS. 1A and 1B, the circuit pattern 4 has terminals 41 and wiring 42.

[0052] At least a portion of the terminal 41 is disposed on the second portion 32 of the base insulating layer 3. In the first embodiment, the entire terminal 41 is disposed on the second portion 32. Therefore, in the first embodiment, the distance D1 (see FIG. 2) between the terminal 41 and the metal layer 2 in the thickness direction is approximately the same as the second thickness T2 (see FIG. 2) of the second portion 32 of the base insulating layer 3. The terminal 41 has a square land shape. More specifically, the terminal 41 extends in the first direction and the second direction. The terminal 41 has a substantially rectangular shape. The wired circuit board 1 may have multiple terminals 41. When the wired circuit board 1 has multiple terminals 41, the multiple terminals 41 are lined up, for example, in the first direction.

[0053] The wiring 42 is connected to the terminal 41. More specifically, the wiring 42 has a connection portion 420 that is connected to the terminal 41.

[0054] The connecting portion 420 is continuous with the other end of the terminal 41 in the second direction. In the first embodiment, the connecting portion 420 extends in the second direction. The direction in which the connecting portion 420 extends is not limited. The connecting portion 420 may extend from the other end of the terminal 41 in the second direction and then bend toward the first direction.

[0055] The width W1 of the terminal 41 is different from the width W2 of the connection portion 420. More specifically, the width W1 of the terminal 41 is wider than the width W2 of the connection portion 420.

[0056] The width W1 of the terminal 41 is the length of the terminal 41 in the first direction. In other words, the terminal 41 has an end E1 to which the connecting portion 420 is connected, and an end E2 that is located on the opposite side of the connecting portion 420 from the end E1. The width W1 of the terminal 41 is the length of the terminal 41 in a direction perpendicular to the direction from the end E1 to the end E2.

[0057] The width W2 of the connecting portion 420 is the length in the first direction of the connecting portion 420. In other words, the width W2 of the connecting portion 420 is the length of the connecting portion 420 in a direction perpendicular to the direction in which the connecting portion 420 extends.

[0058] The length L of the connection portion 420 is 1000 μm. In other words, the "connection portion 420" is the portion of the wiring 42 that is 1000 μm from the terminal 41.

[0059] At least a portion 420A of the connecting portion 420 is disposed on the first portion 31 of the base insulating layer 3. In the first embodiment, an end portion 420B of the connecting portion 420 is disposed on the second portion 32 together with the terminal 41. The end portion 420B is disposed between the portion 420A and the terminal 41. There is no lower limit to the length of the end portion 420B. The length of the end portion 420B may be zero. That is, the entire connecting portion 420 may be disposed on the first portion 31.

[0060] 2, in the first embodiment, the distance D2 in the thickness direction between the part 420A and the metal layer 2 is approximately the same as the first thickness T1 of the first portion 31 of the base insulating layer 3. Therefore, in the thickness direction, the distance D1 between the entire terminal 41 and the metal layer 2 is longer than the distance D2 between at least the part 420A of the connection portion 420 and the metal layer 2. The difference between the distance D1 and the distance D2 is, for example, 1 μm to 30 μm, or preferably 5 μm to 20 μm.

[0061] That is, terminal 41, which is wider than connection portion 420, is disposed farther from metal layer 2 than at least part 420A of connection portion 420.

[0062] Therefore, the impedance of the terminal 41 can be made closer to the impedance of the connection portion 420 .

[0063] As a result, an increase in return loss caused by a discontinuity in impedance between terminal 41 and connection portion 420 can be suppressed.

[0064] (4) Cover insulation layer The cover insulating layer 5 covers the wiring 42. The cover insulating layer 5 is disposed on the base insulating layer 3 in the thickness direction. The cover insulating layer 5 does not cover the terminals 41. The cover insulating layer 5 is made of a resin. Examples of resins include polyimide, maleimide, epoxy resin, polybenzoxazole, and polyester.

[0065] 2. Manufacturing method of the wired circuit board of the first embodiment Next, a method for manufacturing the wired circuit board 1 of the first embodiment will be described.

[0066] The method for manufacturing the wired circuit board 1 includes a metal layer forming step (see FIG. 3A), a base insulating layer forming step (see FIG. 3B), a patterning step (see FIG. 3C), and a cover insulating layer forming step (see FIG. 2).

[0067] (1) Metal layer formation process In the metal layer forming step, as shown in FIG. 3A, the second metal layer 22 is formed on one surface of the first metal layer 21 in the thickness direction by, for example, electrolytic plating.

[0068] (2) Base insulating layer formation process 3B, in the base insulating layer forming step, the base insulating layer 3 is formed on the metal layer 2. In the first embodiment, the base insulating layer 3 is formed on the second metal layer 22.

[0069] In the base insulating layer forming step, a first portion 31 and a second portion 32 are formed in the base insulating layer 3 by gradational exposure.

[0070] More specifically, first, a photosensitive resin solution (varnish) is applied onto the metal layer 2 and dried to form a coating film of the photosensitive resin.

[0071] Next, the photosensitive resin coating is subjected to gradational exposure using a photomask having a light-shielding portion, a fully transparent portion, and a semi-transparent portion. The light-shielding portion faces the portion of the photosensitive resin coating where the insulating base layer 3 will not be formed. The semi-transparent portion faces the portion of the photosensitive resin coating where the first portion 31 will be formed. The fully transparent portion faces the portion of the photosensitive resin coating where the second portion 32 will be formed.

[0072] Next, the exposed coating film is developed. The portions of the coating film facing the semi-transparent portions are developed thinner than the portions facing the fully transparent portions. As a result, the insulating base layer 3 is formed on the metal layer 2 in the above-mentioned pattern.

[0073] (3) Patterning process Next, as shown in FIG. 3C, in a patterning step, a circuit pattern 4 is formed on the insulating base layer 3.

[0074] In the patterning process, first, a seed layer is formed in the thickness direction on one surface of the insulating base layer 3 and one surface of the second metal layer 22. The seed layer is formed by, for example, sputtering. Examples of materials for the seed layer include chromium, copper, nickel, titanium, and alloys thereof.

[0075] Next, a plating resist is attached to one surface in the thickness direction of the second metal layer 22. The plating resist covers the insulating base layer 3.

[0076] Next, the plating resist is exposed to light and developed, which removes the plating resist from the area where the circuit pattern 4 is to be formed, exposing the seed layer in the area where the circuit pattern 4 is to be formed. On the other hand, the plating resist remains in the area where the circuit pattern 4 is not to be formed.

[0077] Next, a circuit pattern 4 is formed on the exposed seed layer by electrolytic plating. After the electrolytic plating is completed, the plating resist is stripped off, and the seed layer exposed by the stripping of the plating resist is removed by etching.

[0078] (4) Cover insulating layer forming process Next, as shown in FIG. 2, in the insulating cover layer forming step, the insulating cover layer 5 is formed on the insulating base layer 3.

[0079] In detail, in the cover insulating layer forming process, first, a photosensitive resin solution (varnish) is applied onto the circuit pattern 4, the base insulating layer 3, and the second metal layer 22, and then dried to form a photosensitive resin coating.

[0080] Next, the photosensitive resin coating is exposed to light and developed, thereby forming the insulating cover layer 5 on the insulating base layer 3.

[0081] 3. Effects (1) According to the wired circuit board 1 of the first embodiment, as shown in FIG. 2, in the thickness direction, the distance D1 between the entire terminal 41 and the metal layer 2 is longer than the distance D2 between the metal layer 2 and a portion 420A of the connection portion 420 of the wiring 42 that is arranged on the first portion 31 of the base insulating layer 3.

[0082] Therefore, the impedance of the entire terminal 41 can be increased to approach the impedance of the connection portion 420.

[0083] As a result, the difference in impedance between the terminal 41 and the wiring 42 can be reduced without opening the metal layer 2.

[0084] (2) According to the wired circuit board 1 of the first embodiment, as shown in Fig. 2, the base insulating layer 3 has a first portion 31 having a first thickness T1 and a second portion 32 having a second thickness T2 that is thicker than the first thickness T1. A part 420A of the connection portion 420 is disposed on the first portion 31. The entire terminal 41 is disposed on the second portion 32.

[0085] Therefore, the second portion 32 of the base insulating layer 3 makes it possible to make the distance D1 between the entire terminal 41 and the metal layer 2 longer than the distance D2 between the part 420A of the connection portion 420 and the metal layer 2.

[0086] (3) According to the method for manufacturing the wired circuit board 1 of the first embodiment, as shown in FIG. 3B, in the base insulating layer forming step, the first portion 31 and the second portion 32 are formed in the base insulating layer 3 by gradation exposure.

[0087] Therefore, the first portion 31 and the second portion 32 can be easily formed in the insulating base layer 3.

[0088] 4. Modification of the First Embodiment A modified example of the first embodiment will be described. In the modified example, the same members as those in the first embodiment are given the same reference numerals, and the description thereof will be omitted.

[0089] (1) In the base insulating layer forming step shown in FIG. 3B, the first portion 31 and the second portion 32 may be formed in the base insulating layer 3 by etching.

[0090] More specifically, first, a photosensitive resin solution (varnish) is applied onto the metal layer 2 and dried to form a coating film of the photosensitive resin.

[0091] Next, the photosensitive resin coating is exposed to light and developed, thereby forming the insulating base layer 3 having the second thickness T2 on the metal layer 2.

[0092] Next, the first portion 31 of the base insulating layer 3 is etched to make the thickness of the first portion 31 thinner than the second portion 32.

[0093] In this modification, the first portion 31 and the second portion 32 can also be easily formed in the insulating base layer 3.

[0094] (2) As shown in FIG. 4, the second portion 32 may have a first layer 321 and a second layer 322 disposed on the first layer 321.

[0095] In this case, the method for manufacturing the wired circuit board 1 includes a first insulating layer forming step (see FIG. 5A) and a second insulating layer forming step (see FIG. 5B) instead of the above-described base insulating layer forming step (see FIG. 3B). That is, in this modification, the method for manufacturing the wired circuit board 1 includes a metal layer forming step (see FIG. 3A), a first insulating layer forming step (see FIG. 5A), a second insulating layer forming step (see FIG. 5B), a patterning step (see FIG. 3C), and a cover insulating layer forming step (see FIG. 2).

[0096] As shown in FIG. 5A, in the first insulating layer forming step, the first portion 31 and the first layer 321 of the second portion 32 are formed on the metal layer 2.

[0097] More specifically, in the first insulating layer forming step, a photosensitive resin solution (varnish) is applied onto the metal layer 2 and dried to form a photosensitive resin coating.

[0098] Next, the photosensitive resin coating is exposed to light and developed. As a result, the first portion 31 and the first layer 321 of the second portion 32 are formed on the metal layer 2 with a first thickness T1 (see FIG. 4). The first layer 321 of the second portion 32 is integral with the first portion 31. In other words, the first layer 321 of the second portion 32 is made of the same material as the first portion 31 and is integral with the first portion 31. There is no interface between the first portion 31 and the first layer 321.

[0099] Next, as shown in FIG. 5B, in the second insulating layer forming step, the second layer 322 of the second portion 32 is formed on the first layer 321.

[0100] More specifically, in the second insulating layer forming step, a photosensitive resin solution (varnish) is applied onto the first layer 321 and dried to form a photosensitive resin coating. The photosensitive resin coating may also be formed on the first portion 31 and the metal layer 2.

[0101] Next, the photosensitive resin coating is exposed to light and developed. This forms a second layer 322 on the first layer 321. In this modification, the sum of the thickness of the first layer 321 and the thickness of the second layer 322 is the second thickness T2 (see FIG. 4). An interface exists between the first layer 321 and the second layer 322. In other words, the second layer 322 of the second portion 32 is not unitary with the first portion 31 and the first layer 321.

[0102] In this modified example, as shown in Figure 4, in the thickness direction, the distance D1 between the entire terminal 41 and the metal layer 2 is longer than the distance D2 between the metal layer 2 and a portion 420A of the connection portion 420 of the wiring 42 that is arranged on the first portion 31 of the base insulating layer 3.

[0103] Therefore, the impedance of the entire terminal 41 can be increased to approach the impedance of the connection portion 420.

[0104] As a result, the difference in impedance between the terminal 41 and the wiring 42 can be reduced without opening the metal layer 2.

[0105] Furthermore, as shown in FIGS. 5A and 5B, the first portion 31 and the second portion 32 can be easily formed in the base insulating layer 3 by the first insulating layer forming step and the second insulating layer forming step.

[0106] 6, the entire connecting portion 420 may be disposed on the first portion 31. In this case, the distance D1 between the entire terminal 41 and the metal layer 2 is longer than the distance D2 between the entire connecting portion 420 and the metal layer 2.

[0107] Therefore, the difference in impedance between the entire terminal 41 and the entire connecting portion 420 can be reduced.

[0108] As a result, the difference in impedance between the terminal 41 and the wiring 42 can be further reduced.

[0109] (4) A portion of the terminal 41 may be disposed on the first portion 31 together with the connecting portion 420. Specifically, as shown in FIGS. 7A and 7B , the second portion 32 may be smaller than the terminal 41, and a peripheral portion E of the terminal 41 may be disposed on the first portion 31 together with the connecting portion 420. That is, one end of the terminal 41 in the first direction, the other end of the terminal 41 in the first direction, one end of the terminal 41 in the second direction, and the other end of the terminal 41 in the second direction may be disposed on the first portion 31. Note that a central portion C of the terminal 41 is disposed on the second portion 32. The central portion C is the central portion of the terminal 41 in the first direction and the central portion of the terminal 41 in the second direction.

[0110] In this case, the area of ​​the second portion 32 is, for example, 30% or more, preferably 50% or more, and more preferably 80% or more of the area of ​​the terminal 41.

[0111] (5) As shown in FIGS. 8A and 8B, only the other end of the terminal 41 in the second direction may be disposed on the first portion 31 together with the connecting portion 420.

[0112] (6) The terminal 41 may have multiple conductor layers. Specifically, as shown in FIGS. 9A and 9B , the terminal 41 may have a first conductor layer 411 and a second conductor layer 412. At least a portion of the first conductor layer 411 is disposed on the second portion 32 of the base insulating layer 3. The connection portion 420 is connected to the first conductor layer 411. In this modification, the entire first conductor layer 411 is disposed on the second portion 32 of the base insulating layer 3. Note that, as in the above-described modifications (4) and (5), a portion of the first conductor layer 411 may be disposed on the first portion 31 together with the connection portion 420. Examples of materials for the first conductor layer 411 include the same materials as those for the circuit pattern 4 described above. The second conductor layer 412 is disposed on the first conductor layer 411. The second conductor layer 412 may be made of the same material as the first conductor layer 411. The second conductor layer 412 may be made of a different material (eg, solder) than the first conductor layer 411.

[0113] (7) In the above-described modifications (1) to (6), similarly to the first embodiment, the difference in impedance between the terminal 41 and the wiring 42 can be reduced without opening the metal layer 11.

[0114] 5. Wired circuit board according to the second embodiment Next, a wired circuit board 10 according to a second embodiment will be described. In the second embodiment, the same members as those in the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted.

[0115] As shown in FIGS. 10A and 10B, the wired circuit board 10 of the second embodiment extends in the first and second directions, similar to the wired circuit board 1 of the first embodiment.

[0116] As shown in FIG. 11, the wired circuit board 10 of the second embodiment includes a metal layer 11, a base insulating layer 12, a circuit pattern 4, and a cover insulating layer 5.

[0117] (1) Metal layer The metal layer 11 supports the base insulating layer 12, the circuit pattern 4, and the cover insulating layer 5. The metal layer 11 has a recess 110.

[0118] 10B, the recess 110 overlaps with the terminal 41 in the thickness direction. In the second embodiment, the recess 110 is larger than the terminal 41 in the first and second directions. In the second embodiment, the entire terminal 41 overlaps with the recess 110. Furthermore, an end 420B of the connecting portion 420 overlaps with the recess 110 together with the terminal 41. A portion 420A of the connecting portion 420 does not overlap with the recess 110.

[0119] 11, the recess 110 is recessed in the thickness direction away from the terminal 41. As a result, the distance D1 between the entire terminal 41 and the metal layer 11 is longer than the distance D2 between the part 420A of the connection portion 420 and the metal layer 11 in the thickness direction.

[0120] That is, in the second embodiment as well, the terminal 41, which is wider than the connection portion 420, is disposed farther away from the metal layer 11 than the part 420A of the connection portion 420.

[0121] Therefore, the impedance of the terminal 41 can be made closer to the impedance of the connection portion 420 .

[0122] As a result, an increase in return loss caused by a discontinuity in impedance between terminal 41 and connection portion 420 can be suppressed.

[0123] The metal layer 11 may have a plurality of layers made of different metals. In the second embodiment, the metal layer 11 has a first metal layer 111 and a second metal layer 112.

[0124] The first metal layer 111 is made of the same material as the first metal layer 21 of the first embodiment.

[0125] The second metal layer 112 is disposed on one side of the first metal layer 111 in the thickness direction. The second metal layer 112 is disposed on one surface of the first metal layer 111 in the thickness direction. The second metal layer 112 is disposed between the first metal layer 111 and the insulating base layer 12 in the thickness direction. The second metal layer 112 is made of the same material as the first metal layer 111 in the first embodiment. The recess 110 may penetrate the second metal layer 112. In other words, the second metal layer 112 may have a through hole 112A. The through hole 112A overlaps with the terminal 41 in the thickness direction.

[0126] (2) Base insulation layer The base insulating layer 12 is disposed on one side of the metal layer 11 in the thickness direction. The base insulating layer 12 is disposed on one surface of the metal layer 11 in the thickness direction. The base insulating layer 12 insulates the metal layer 11 from the circuit pattern 4. The base insulating layer 12 is made of the same resin as the base insulating layer 3 in the first embodiment. A portion of the base insulating layer 12 is disposed in the recess 110 of the metal layer 11. When the second metal layer 112 has a through hole 112A, a portion of the base insulating layer 12 is disposed in the through hole 112A of the second metal layer 112. Specifically, the base insulating layer 12 has a first portion 121 and a second portion 122.

[0127] The first portion 121 is disposed in the thickness direction between the second metal layer 112 and the circuit pattern 4. The first portion 121 has a first thickness T1.

[0128] The second portion 122 is disposed within the recess 110 of the metal layer 11. The second portion 122 is disposed between the first metal layer 111 and the circuit pattern 4 in the thickness direction. The second portion 122 insulates the first metal layer 111 from the circuit pattern 4. The second portion 122 is continuous with the first portion 121. The entire second portion 122 is unitary with the first portion 121. In other words, the entire second portion 122 is made from the same material as the first portion 121 and is integral with the first portion 121. There is no interface between the first portion 121 and the second portion 122. The second portion 122 has a second thickness T2. The second thickness T2 is thicker than the first thickness T1.

[0129] In the second embodiment, the entire terminal 41 is disposed on the second portion 122. A part 420A of the connection portion 420 is disposed on the first portion 121. An end portion 420B of the connection portion 420 is disposed on the second portion 122 together with the terminal 41.

[0130] The distance D1 between the terminal 41 and the metal layer 11 in the thickness direction is approximately the same as the second thickness T2 of the second portion 122 of the base insulating layer 12, and the distance D2 between the portion 420A and the metal layer 11 in the thickness direction is approximately the same as the first thickness T1 of the first portion 121 of the base insulating layer 12.

[0131] Therefore, in the second embodiment, similarly to the first embodiment, in the thickness direction, a distance D1 between the entire terminal 41 and the metal layer 11 is longer than a distance D2 between a part 420A of the connection portion 420 and the metal layer 11. In other words, the terminal 41, which is wider than the connection portion 420, is disposed farther away from the metal layer 11 than the part 420A of the connection portion 420.

[0132] Therefore, the impedance of the terminal 41 can be made closer to the impedance of the connection portion 420 .

[0133] As a result, the return loss caused by the discontinuity in impedance between terminal 41 and connection portion 420 can be reduced.

[0134] 6. Method for manufacturing the wired circuit board according to the second embodiment The method for manufacturing the wired circuit board 10 includes a metal layer forming process (see FIG. 12A), a through hole forming process (see FIG. 12B) as an example of a recess forming process, a base insulating layer forming process (see FIG. 12C), a patterning process (see FIG. 12D), and a cover insulating layer forming process (see FIG. 11).

[0135] (1) Metal layer formation process In the metal layer forming step, as shown in FIG. 12A, a second metal layer 112 is formed on one surface of a first metal layer 111 in the thickness direction in the same manner as in the metal layer forming step of the first embodiment.

[0136] (2) Through-hole formation process 12B, in the through-hole forming step, the second metal layer 112 is etched to form a through-hole 112A in the second metal layer 112. In other words, the second metal layer 112 of the metal layer 11 is etched to form a recess 110 in the metal layer 11.

[0137] (3) Base insulating layer formation process Next, as shown in FIG. 12C, in the base insulating layer forming step, the base insulating layer 12 is formed on the metal layer 11 so that the base insulating layer 12 fills the through-holes 112A (ie, the recesses 110).

[0138] Specifically, first, a photosensitive resin solution (varnish) is applied onto the metal layer 11. At this time, the photosensitive resin solution is applied to one surface of the second metal layer 112 and also fills the through-holes 112A (recesses 110).

[0139] Next, the photosensitive resin solution is dried, whereby a coating of the photosensitive resin is formed on one surface of the second metal layer 112 and in the through-holes 112A (recesses 110).

[0140] Next, the photosensitive resin coating is exposed to light and developed, thereby forming the insulating base layer 12 on the metal layer 11. The first portion 121 of the insulating base layer 12 is disposed on one surface of the second metal layer 112. The second portion 122 of the insulating base layer 12 is filled in the through-hole 112A (recess 110).

[0141] (4) Patterning process Next, as shown in FIG. 12D, in the patterning step, the circuit pattern 4 is formed on the insulating base layer 12 in the same manner as in the patterning step of the first implementation step.

[0142] (5) Cover insulating layer forming process Next, as shown in FIG. 11, in the cover insulating layer forming step, the cover insulating layer 5 is formed on the base insulating layer 12 in the same manner as in the cover insulating layer forming step of the first implementation step.

[0143] 7. Action and Effects (1) According to the wired circuit board 10 of the second embodiment, as shown in Fig. 11, the metal layer 11 has a recess 110 that is recessed in the thickness direction in a direction away from the terminal 41. As shown in Fig. 10B, the recess 110 overlaps the entire terminal 41 in the thickness direction.

[0144] Therefore, as shown in FIG. 11, recess 110 in metal layer 11 allows distance D1 between the entire terminal 41 and metal layer 11 to be longer than distance D2 between part 420A of connection portion 420 and metal layer 11.

[0145] This increases the overall impedance of the terminal 41 and makes it possible to approach the impedance of the connection portion 420.

[0146] As a result, the difference in impedance between the terminal 41 and the wiring 42 can be reduced without opening the metal layer 11.

[0147] (2) According to the wired circuit board 10 of the second embodiment, as shown in FIG. 12B, the second metal layer 112 is etched to form the through-hole 112A in the second metal layer 112 in the through-hole forming step.

[0148] Therefore, the recess 110 can be easily formed in the metal layer 11 by the simple process of etching the second metal layer 112.

[0149] 8. Modification of the Second Embodiment Next, a modified example of the second embodiment will be described. In the modified example, the same members as those in the second embodiment will be given the same reference numerals, and the description thereof will be omitted.

[0150] (1) The manufacturing method of the wired circuit board 10 does not have to include the through-hole forming step (recess forming step). As shown in Figures 13A and 13B, in the metal forming step, a second metal layer 112 having a through-hole 112A may be formed on a first metal layer 111.

[0151] In detail, as shown in FIG. 13A, in the metal layer formation process, for example, the portion where the through hole 112A (recess 110) is to be formed is covered with plating resist R, and then the second metal layer 112 is formed on one side of the first metal layer 111 in the thickness direction by electrolytic plating.

[0152] Thereafter, as shown in FIG. 13B, the plating resist R is peeled off.

[0153] According to this modification, by forming the second metal layer 112 having the through-holes 112A on the first metal layer 111, the metal layer 11 having the recesses 110 can be easily formed.

[0154] 14, the metal layer 11 does not have to have the second metal layer 112. The metal layer 11 may be a single layer made of the same material as the first metal layer 111.

[0155] In this case, as shown in Fig. 15A, in a recess formation step, the metal layer 11 is etched to form recesses 110 in the metal layer 11. Next, as shown in Fig. 15B, in a base insulating layer formation step, the base insulating layer 12 is formed on the metal layer 11 so that the base insulating layer 12 fills the recesses 110. Next, as shown in Fig. 15C, in a patterning step, a circuit pattern 4 is formed on the base insulating layer 12. Next, as shown in Fig. 14, in a cover insulating layer formation step, a cover insulating layer 5 is formed on the base insulating layer 12.

[0156] 16A, the entire connecting portion 420 may be disposed on the first portion 121. In this case, the distance D1 between the entire terminal 41 and the metal layer 11 is longer than the distance D2 between the entire connecting portion 420 and the metal layer 11.

[0157] Therefore, the difference in impedance between the entire terminal 41 and the entire connecting portion 420 can be reduced.

[0158] As a result, the difference in impedance between the terminal 41 and the wiring 42 can be further reduced.

[0159] (4) In the second embodiment, as in the first embodiment described above, a portion of the terminal 41 may be disposed on the first portion 121 together with the connecting portion 420. Specifically, as shown in FIG. 16B , the second portion 122 may be smaller than the terminal 41, and the peripheral edge E of the terminal 41 may be disposed on the first portion 121 together with the connecting portion 420. That is, one end of the terminal 41 in the first direction, the other end of the terminal 41 in the first direction, one end of the terminal 41 in the second direction, and the other end of the terminal 41 in the second direction may be disposed on the first portion 121. Note that the central portion C of the terminal 41 is disposed on the second portion 122. The central portion C is the central portion of the terminal 41 in the first direction and the central portion of the terminal 41 in the second direction.

[0160] In this case, the area of ​​the second portion 122 is, for example, 30% or more, preferably 50% or more, and more preferably 80% or more of the area of ​​the terminal 41.

[0161] (5) In the second embodiment, as in the first embodiment described above, the terminal 41 may have multiple conductor layers. Specifically, as shown in FIGS. 17A and 17B , the terminal 41 may have a first conductor layer 411 and a second conductor layer 412. At least a portion of the first conductor layer 411 is disposed on the second portion 122 of the base insulating layer 12. The connecting portion 420 is connected to the first conductor layer 411. In this modification, the entire first conductor layer 411 is disposed on the second portion 122 of the base insulating layer 12. A portion of the first conductor layer 411, together with the connecting portion 420, may be disposed on the first portion 121. The second conductor layer 412 is disposed on the first conductor layer 411.

[0162] (6) In the above-described modifications (1) to (5), similarly to the second embodiment, the difference in impedance between the terminal 41 and the wiring 42 can be reduced without opening the metal layer 11. [Explanation of symbols]

[0163] 1 Wiring circuit board 2 metal layer 21 1st metal layer 22 Second metal layer 3 Base insulation layer 31 Part 1 32 Part 2 4 Circuit Pattern 41 terminals 42 Wiring 420 Connection Part of the 420A connection 321 1st layer of 2nd part 322 Second Layer of Second Part 10 Wiring circuit board 11 Metal layer 110 recess 111 1st metal layer 112 Second metal layer 112A through hole 12 Base insulation layer D1 Distance between terminal and metal layer D2 Distance between connection and metal layer W1 Terminal width W2 Width of connection

Claims

1. a metal layer; a circuit pattern having terminals and wiring connected to the terminals; an insulating layer disposed between the metal layer and the circuit pattern in a thickness direction of the metal layer; Equipped with the wiring has a connection portion connected to the terminal, The width of the terminal is wider than the width of the connection portion, a distance between at least a portion of the terminal and the metal layer in the thickness direction is longer than a distance between at least a portion of the connection portion and the metal layer.

2. The printed circuit board according to claim 1 , wherein a distance between all of said terminals and said metal layer is longer than a distance between at least a portion of said connection portion and said metal layer.

3. The printed circuit board according to claim 1 , wherein a distance between all of said terminals and said metal layer is longer than a distance between all of said connection portions and said metal layer.

4. The insulating layer is a first portion having a first thickness; a second portion having a second thickness greater than the first thickness; and At least a portion of the connection portion is disposed on the first portion; The printed circuit board according to claim 1 , wherein at least a portion of the terminal is disposed on the second portion.

5. The printed circuit board according to claim 4 , wherein all of the terminals are disposed on the second portion.

6. The printed circuit board according to claim 4 , wherein all of the connection portions are disposed on the first portion.

7. The second portion is a first layer unitary with said first portion; a second layer disposed on the first layer; and The wired circuit board according to any one of claims 4 to 6, comprising:

8. 7. The printed circuit board according to claim 4, wherein the entire second portion is unitary with the first portion.

9. The metal layer is a first metal layer; The printed circuit board according to claim 1 , further comprising a second metal layer disposed between the first metal layer and the insulating layer in the thickness direction.

10. The second metal layer is The wired circuit board according to claim 9 , further comprising a through hole overlapping with the terminal in the thickness direction.

11. The metal layer is 10. The wired circuit board according to claim 1, further comprising a recess that overlaps with the terminal in the thickness direction and is recessed in a direction away from the terminal in the thickness direction.

12. 8. The method for manufacturing a wired circuit board according to claim 7, a first insulating layer forming step of forming the first portion and the first layer of the second portion on the metal layer; a second insulating layer forming step of forming the second layer of the second portion on the first layer; a patterning step of forming the circuit pattern on the insulating layer; A method for manufacturing a wired circuit board, comprising:

13. 9. The method for manufacturing a wired circuit board according to claim 8, an insulating layer forming step of forming the insulating layer on the metal layer; a patterning step of forming the circuit pattern on the insulating layer; Including, In the insulating layer forming step, the first portion and the second portion are formed in the insulating layer by gradation exposure or etching.

14. The method for manufacturing a wired circuit board according to claim 10, a metal layer forming step of forming the second metal layer having the through-hole on the first metal layer; an insulating layer forming step of forming the insulating layer on the second metal layer so that the insulating layer fills the through-hole; a patterning step of forming the circuit pattern on the insulating layer; A method for manufacturing a wired circuit board, comprising:

15. The method for manufacturing a wired circuit board according to claim 10, a metal layer forming step of forming the second metal layer on the first metal layer; a through-hole forming step of etching the second metal layer to form the through-hole in the second metal layer; an insulating layer forming step of forming the insulating layer on the second metal layer so that the insulating layer fills the through-hole; a patterning step of forming the circuit pattern on the insulating layer; A method for manufacturing a wired circuit board, comprising:

16. The method for manufacturing the wired circuit board according to claim 11, a recess forming step of etching the metal layer to form the recess in the metal layer; an insulating layer forming step of forming the insulating layer on the metal layer so that the insulating layer fills the recess; a patterning step of forming the circuit pattern on the insulating layer; A method for manufacturing a wired circuit board, comprising:

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