Wiring circuit board

Abstract

The wiring circuit substrate (X) of the present application includes an insulating layer (11, 12), a wiring layer (21), a pad portion (22), and a conductive connection portion (30). The wiring layer (21) is disposed on one side in the thickness direction of the insulating layer (11) and has a connection portion (21a). The insulating layer (12) is disposed on one side in the thickness direction of the insulating layer (11) so as to cover the wiring layer (21). The pad portion (22) is disposed on one side in the thickness direction of the insulating layer (12). The insulating layer (12) has a through opening portion (12A) that penetrates the insulating layer (12) in the thickness direction. The through opening portion (12A) is open along at least a portion of a peripheral end portion (22a) of the pad portion (22). The connection portion (21a) of the wiring layer (21) faces the through opening portion (12A). The conductive connection portion (30) is disposed in the through opening portion (12A), is connected to at least a portion of the peripheral end portion (22a) of the pad portion (22), is connected to the connection portion (21a), and electrically connects the wiring layer (21) and the pad portion (22).

Description

Technical Field

[0001] This invention relates to a wiring circuit board. Background Technology

[0002] In wiring circuit boards with a multilayer wiring structure, conventionally, pads for external connections disposed on one side of the outermost interlayer insulating layer (the outer side) are sometimes connected to other wiring on the other side of the insulating layer via wiring patterned on that side of the insulating layer and vias penetrating the insulating layer. However, in such a structure, when multiple pads are disposed at a high density within a predetermined area of ​​the wiring circuit board, it is sometimes impossible to form the pads at the desired density.

[0003] On the other hand, from the viewpoint of achieving a high-density arrangement of pads, in the wiring circuit board of the multilayer wiring structure, a so-called pad-on-via structure is sometimes adopted.

[0004] Figure 10 This is an example of a configuration where pads are positioned within a through-hole. Figure 10 The illustrated pad configuration in a via includes an insulating layer 91 on a substrate 90, a wiring layer 92 on the insulating layer 91, and an insulating layer 93 disposed on the insulating layer 91 to cover the wiring layer 92. The insulating layer 93 has a via 93a, and the wiring layer 92 has a portion 92a facing the via 93a. A conductor layer 94 is formed along this portion 92a, the inner wall surface of the via 93a, and a region 93b in the insulating layer 93 surrounding the upper end of the via 93a in the figure. This conductor layer 94 is, for example, circular in plan view and forms the pad portion. For example, technology related to a pad configuration in a via is described in Patent Document 1 below.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Application Publication No. 2016-18577 Summary of the Invention

[0008] The problem the invention aims to solve

[0009] However, in Figure 10 The pads shown are configured in a through-hole structure, and the conductor layer 94 forming the pad portion has a recess 94a on its exposed surface. Therefore, for example, when a solder bump B is bonded to the conductor layer 94, a gap G (solder gap) is easily formed between the solder bump B and the conductor layer 94. The formation of the gap G is a cause of reduced bonding strength between the solder bump B and the conductor layer 94, and is therefore undesirable.

[0010] The present application provides a wiring circuit substrate suitable for ensuring surface flatness of a pad portion and achieving high-density arrangement of the pad portion.

[0011] Solution to the problem

[0012] The present application [1] includes a wiring circuit substrate including: a first insulating layer; a wiring layer arranged on one side in a thickness direction of the first insulating layer; a second insulating layer arranged on the one side in the thickness direction of the first insulating layer so as to cover the wiring layer; a pad portion arranged on one side in the thickness direction of the second insulating layer; and a conductive connection portion electrically connecting the wiring layer and the pad portion, the second insulating layer having a through-opening portion that penetrates the second insulating layer in the thickness direction and opens along at least a part of a peripheral end portion of the pad portion, the wiring layer having a connection portion facing the through-opening portion, the conductive connection portion being arranged in the through-opening portion, connected to the at least a part of the peripheral end portion of the pad portion, and connected to the connection portion of the wiring layer.

[0013] As described above, the wiring circuit substrate of the present application has the pad portion arranged on one side in the thickness direction of the second insulating layer. The pad portion is located on the second insulating layer, and thus is easily formed as a pad portion having a flat exposed surface (main surface for external connection). That is, the wiring circuit substrate of the present application is suitable for ensuring surface flatness of the pad portion. Meanwhile, as described above, the wiring circuit substrate of the present application has the conductive connection portion connected to at least a part of the peripheral end portion of the pad portion and connected to the connection portion of the wiring layer. In the wiring circuit substrate of the present application, a wiring pattern on the second insulating layer for electrically connecting the wiring layer and the pad portion is not required. In the wiring circuit substrate of the present application in which the wiring layer and the pad portion are electrically connected without providing such a wiring pattern on the second insulating layer, the pad portion is easily arranged at high density. That is, the wiring circuit substrate of the present application is suitable for achieving high-density arrangement of the pad portion.

[0014] The present application [2] includes the wiring circuit substrate described in the above [1], in which the through-opening portion opens along an entire circumference of the peripheral end portion of the pad portion, and the conductive connection portion is connected to the peripheral end portion throughout the entire circumference.

[0015] Such a structure is suitable for ensuring a large connection area between the pad portion and the conductive connection portion, and thus is suitable for achieving high connection reliability.

[0016] The present application [3] includes the wiring circuit substrate described in the above [1], in which the conductive connection portion has a shape extending from the connection portion of the wiring layer to the peripheral end portion of the pad portion when viewed in the thickness direction.

[0017] Such a structure is suitable for ensuring a large connection area between the pad portion and the conductive connection portion, and is thus suitable for achieving high connection reliability.

[0018] The wiring circuit substrate of the present application [4] includes any one of the wiring circuit substrates described in the above [1] to [3], wherein the opening end of the through opening portion in the side of the thickness direction of the second insulating layer includes a first edge in contact with the pad portion and along the peripheral end portion, and a second edge apart from the pad portion and opposite to the first edge, and the conductive connection portion does not contact a part or the whole of the second edge.

[0019] Such a structure is suitable for further providing the pad portion near the second edge of the through opening portion in the side of the thickness direction of the second insulating layer, and is thus suitable for achieving high-density arrangement of the pad portion.

[0020] The wiring circuit substrate of the present application [5] includes any one of the wiring circuit substrates described in the above [1] to [4], wherein the connection portion of the wiring layer closes the opening end of the through opening portion in the side of the thickness direction of the second insulating layer.

[0021] Such a structure is suitable for ensuring a large connection area between the conductive connection portion arranged in the through opening portion and the wiring layer, and is thus suitable for achieving high connection reliability. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 is a partial cross-sectional view of an embodiment of the wiring circuit substrate of the present application.

[0023] Figure 2 is a partial plan view of the wiring circuit substrate shown in Figure 1

[0024] Figure 3 is a partial plan view of the wiring circuit substrate shown in Figure 1

[0025] Figure 4 is a plan view showing one example of arrangement of the pad portion.

[0026] Figure 5 shows a part of the manufacturing method of the wiring circuit substrate shown in Figure 1 Figure 5 A indicates a preparation process, Figure 5 B indicates a first insulating layer forming process, Figure 5 C indicates a first conductor layer forming process, Figure 5 D indicates a second insulating layer forming process, Figure 5 E indicates a second conductor layer forming process.

[0027] ​​​Figure 6 is Figure 1 partial cross-sectional views of each modification of the wiring circuit substrate shown in Figure 6 The modification shown in A further has a pad portion formed in a pattern on the second insulating layer. Figure 6 The modification shown in B further has a pad portion formed in a pattern on the second insulating layer, and a third insulating layer. Figure 6 The modification shown in C further has a wiring layer formed in a pattern on the second insulating layer, and a third insulating layer.

[0028] Figure 7 indicates Figure 1 another modification of the wiring circuit substrate shown in Figure 7 A is a partial cross-sectional view of this modification, Figure 7 B is a partial plan view of this modification, Figure 7 C is a partial plan view of this modification omitting a portion (in Figure 7 The pad portion and the conductive connection portion are omitted in C. In this modification, the pad portion is disposed on the same side as the wiring layer in the surface direction with respect to the conductive connection portion connected to the pad portion and the wiring layer.

[0029] Figure 8 indicates Figure 1 another modification of the wiring circuit substrate shown in Figure 8 A is a partial cross-sectional view of this modification, Figure 8 B is a partial plan view of this modification, Figure 8 C is a partial plan view of this modification omitting a portion (in Figure 8 The pad portion and the conductive connection portion are omitted in C. In this modification, the pad portion is disposed on the opposite side from the wiring layer in the surface direction with respect to the conductive connection portion connected to the pad portion and the wiring layer.

[0030] Figure 9 indicates Figure 1 another modification of the wiring circuit substrate shown in Figure 9 A is a partial cross-sectional view of this modification, Figure 9 B is a partial plan view of this modification, Figure 9 C is a plan view of this modification omitting a portion (in Figure 9 The pad portion and the conductive connection portion are omitted in C. In this modification, the conductive connection portion is connected to a portion of the peripheral end portion of the pad portion, and the conductive connection portion has a shape extending from the connection portion of the wiring layer to the peripheral end portion of the pad portion when viewed in projection in the thickness direction.

[0031] Figure 10 is a partial cross-sectional view indicating one example of a configuration in which a pad is disposed in a through-hole. DETAILED DESCRIPTION

[0032] Figures 1 to 3 FIG. 1 is a partial sectional view of a wiring circuit substrate X as an embodiment of the present application. Figure 1 is a partial sectional view of the wiring circuit substrate X, Figure 2 is a partial plan view of the wiring circuit substrate X. Figure 3 is a partial plan view of the wiring circuit substrate X omitting a part (omitting the pad portion 22 and the conductive connection portion 30 described later).

[0033] The wiring circuit substrate X includes a base material S, an insulating layer 11 (a first insulating layer), an insulating layer 12 (a second insulating layer), a wiring layer 21 (a first wiring layer), a pad portion 22 (a first pad portion), and a conductive connection portion 30.

[0034] The base material S is an element for ensuring the mechanical strength of the wiring circuit substrate X, and is provided in the entire or a part of the region of the wiring circuit substrate X.

[0035] In a case where the wiring circuit substrate X is configured as a flexible wiring circuit substrate, the base material S is a flexible base material made of metal. As a material of the flexible base material, for example, copper, copper alloy, stainless steel, and 42 alloy can be given. As the stainless steel, for example, SUS304 based on the specification of AISI (American Iron and Steel Institute) can be given. The thickness of the base material S as the flexible base material made of metal is, for example, 15 μm or more, and, for example, 500 μm or less, and preferably 250 μm or less.

[0036] In a case where the wiring circuit substrate X is configured as a rigid wiring circuit substrate, the base material S is a rigid substrate. As the rigid substrate, for example, a glass epoxy substrate and a metal flat plate can be given. The thickness of the base material S as the rigid substrate is, for example, 0.1 mm or more, and, for example, 2 mm or less, and preferably 1.6 mm or less.

[0037] The insulating layer 11 is a base insulating layer disposed on the thickness direction side of the base material S. In the present embodiment, the insulating layer 11 is disposed on the face on the thickness direction side of the base material S. As a material of the insulating layer 11, for example, a resin material such as polyimide, polyether nitrile, polyether sulfone, polyethylene terephthalate, polyethylene naphthalate, and polyvinyl chloride (as a material of the insulating layers 12 and 13 described later, the same resin material can be given) can be given. The thickness of the insulating layer 11 is, for example, 1 μm or more, and preferably 3 μm or more, and, for example, 35 μm or less, and preferably 15 μm or less.

[0038] The wiring layer 21 is provided on the side of the insulating layer 11 in the thickness direction and has a predetermined pattern shape. In the present embodiment, the wiring layer 21 is provided on the side of the face of the insulating layer 11 in the thickness direction. In addition, the wiring layer 21 has a connection portion 21a facing the through opening portion 12A of the insulating layer 12 described later. The connection portion 21a is located, for example, at the front end portion (free end portion) of the wiring layer 21 of the predetermined pattern or in the vicinity thereof. The thickness of the wiring layer 21 is, for example, 3 μm or more, preferably 5 μm or more, and, for example, 50 μm or less, preferably 30 μm or less. The width (dimension in the direction orthogonal to the extending direction of the wiring layer 21) of the wiring layer 21 is, for example, 5 μm or more, preferably 8 μm or more, and, for example, 100 μm or less, preferably 50 μm or less. As the material of the wiring layer 21, for example, copper, nickel, gold, solder, and alloys thereof can be given, and copper is preferably used.

[0039] The insulating layer 12 is provided on the side of the insulating layer 11 in the thickness direction so as to cover the wiring layer 21. In the present embodiment, the insulating layer 12 is provided on the side of the face of the insulating layer 11 in the thickness direction so as to cover the wiring layer 21. In addition, the insulating layer 12 has a through opening portion 12A that penetrates the insulating layer 12 in the thickness direction. The through opening portion 12A has an opening end 12a on the side in the thickness direction and an opening end 12b on the other side in the thickness direction.

[0040] The through opening portion 12A is opened on the side in the thickness direction along at least a part of the peripheral end portion 22a of the pad portion 22 described later. In the present embodiment, the through opening portion 12A is opened along the entire periphery of the peripheral end portion 22a. That is, the through opening portion 12A has a circular ring shape along the peripheral end portion 22a of the pad portion 22 when viewed from above. Furthermore, the insulating layer 12 includes a boss portion 12B surrounded by the through opening portion 12A. The boss portion 12B has a face on the side in the thickness direction and a tapered peripheral side face 12c that inclines inward as it goes from the other side in the thickness direction toward the side in the thickness direction. The maximum length (diameter of the circular shape in the case where the boss portion 12B has a circular shape when viewed from above) of the face on the side in the thickness direction of the boss portion 12B is, for example, 10 to 1000 μm. In addition, the opening end 12a of the through opening portion 12A has an edge E1 (first edge) that contacts the pad portion 22 on the radially inner side of the through opening portion 12A and along the peripheral end portion 22a, and an edge E2 (second edge) that is opposite the edge E1 (that is, is located on the radially outer side of the through opening portion 12A) and is separated from the pad portion 22. The separation distance between the edges E1 and E2 is, for example, 1 to 100 μm. In the present embodiment, the opening end 12b of the through opening portion 12A is closed by the connection portion 21a of the wiring layer 21.

[0041] The height of the insulating layer 12 from the insulating layer 11 is greater than the thickness of the wiring layer 21, for example, 4 μm or more, preferably 6 μm or more, and, for example, 60 μm or less, preferably 40 μm or less.

[0042] The pad portion 22 is provided on one side in the thickness direction of the insulating layer 12 and has a predetermined planar shape. In the present embodiment, the pad portion 22 is provided on the surface on one side in the thickness direction of the insulating layer 12 (the boss portion 12B). As the planar shape of the pad portion 22, for example, a circle and a rectangle such as a square can be given (exemplarily, a case where the planar shape of the pad portion 22 is a circle is shown). The maximum length of the pad portion 22 in plan view (the diameter of the circle in the case where the planar shape of the pad portion 22 is a circle) is, for example, 15 to 1000 μm. Further, the pad portion 22 has a main surface 22A for external connection and a peripheral end portion 22a. The thickness of the pad portion 22 is, for example, 3 μm or more, preferably 5 μm or more, and, for example, 50 μm or less, preferably 30 μm or less. As the material of the pad portion 22, for example, copper, nickel, gold, solder, and alloys thereof can be given, and copper is preferably used. Further, a plating film such as a Ni-Au plating film or an Au plating film can be formed on the main surface 22A of the pad portion 22 (omitted from illustration). Such a structure is suitable for achieving a good joining strength with a solder such as a solder bump in the pad portion 22.

[0043] The conductive connection portion 30 is an element that electrically connects the wiring layer 21 and the pad portion 22 and is provided in the through opening portion 12A. Specifically, the conductive connection portion 30 is provided on the peripheral side surface 12c of the boss portion 12B, connected to at least a part of the peripheral end portion 22a of the pad portion 22, and connected to the connection portion 21a of the wiring layer 21. In the present embodiment, the conductive connection portion 30 is connected to the entire periphery of the peripheral end portion 22a. Further, the conductive connection portion 30 preferably does not contact a part or the entire edge E2 of the opening end 12a of the through opening portion 12A. Exemplarily, a case where the conductive connection portion 30 does not contact the entire edge E2 is shown.

[0044] In the wiring circuit substrate X, the pad portion 22 is provided in a region where an electronic component such as a semiconductor device configured as a CSP (Chip Size Package) is mounted, for example, in correspondence with the arrangement of the terminals of the electronic component. In the electronic component mounting region of the wiring circuit substrate X, a plurality of pad portions 22 can be arranged, for example, as shown in Figure 4 In the arrangement example shown in Figure 4 , the plurality of pad portions 22 are arranged in a rectangular shape.

[0045] Figure 5 An example of a manufacturing method of the wiring circuit substrate X is shown. Figure 5 The present manufacturing method is shown as a change in the cross section corresponding to Figure 1 .

[0046] In the present manufacturing method, first, as shown in Figure 5 A, a substrate S is prepared (preparation step).

[0047] Next, as shown in Figure 5 B, an insulating layer 11 is formed on the substrate S (first insulating layer formation step). In the case where the insulating layer 11 has a predetermined pattern shape in plan view, in the present step, for example, after a solution (varnish) of a photosensitive resin is applied to the substrate S and dried, an exposure process via a predetermined mask, a subsequent development process, and a subsequent baking process as necessary are performed on a coating film formed thereby. For example, by doing so, the insulating layer 11 can be formed on the substrate S.

[0048] Next, as shown in Figure 5 C, a wiring layer 21 is patterned on the insulating layer 11 (first conductor layer formation step). In the present step, first, for example, a seed layer is formed on an exposed surface of the insulating layer 11 by a sputtering method (omitted from illustration). As a material of the seed layer, for example, Cr, Cu, Ni, Ti, and alloys thereof can be given (the same as a material of a seed layer described later). Next, a resist pattern is formed on the seed layer. The resist pattern has an opening portion having a shape corresponding to a pattern shape of the wiring layer 21. In the formation of the resist pattern, for example, after a resist film is formed by adhering a photosensitive resist film on the seed layer, an exposure process via a predetermined mask, a subsequent development process, and a subsequent baking process as necessary are performed on the resist film (the same as in the formation of a resist pattern described later). In the formation of the wiring layer 21, next, a metal material is grown on the seed layer in the opening portion of the resist pattern by an electroplating method. As the metal material, copper is preferably used. Next, the resist pattern is removed by etching. Next, a portion of the seed layer exposed due to the removal of the resist pattern is removed by etching. For example, by doing so, the wiring layer 21 of a predetermined pattern can be formed on the insulating layer 11.

[0049] In the present manufacturing method, next, as shown in Figure 5 D, an insulating layer 12 is formed on the insulating layer 11 in a manner covering the wiring layer 21 (second insulating layer formation step). In the present step, for example, after a solution (varnish) of a photosensitive resin is applied to the insulating layer 11 and the wiring layers 21, 21 and dried, an exposure process via a predetermined mask, a subsequent development process, and a subsequent baking process as necessary are performed on a coating film formed thereby. In the present step, the insulating layer 12 is formed to have a through opening portion 12A exposing the connection portion 21a of the wiring layer 21.

[0050] Next, as shown in Figure 5As shown in FIG. 8E, the pad portion 22 and the conductive connection portion 30 are formed (2nd conductor portion forming step). In this step, first, a seed layer is formed on the surface of the thickness direction side of the insulating layer 12 and the surface of the through opening portion 12A, for example, by a sputtering method (omitted from the drawing). Next, a resist pattern is formed on the seed layer. The resist pattern has an opening portion having a shape corresponding to the pattern shape of the pad portion 22 and the conductive connection portion 30. In this step, then, a metal material is caused to grow on the seed layer in the opening portion of the resist pattern by an electroplating method. As the metal material, copper is preferably used. Next, the resist pattern is removed by etching. Next, the portion of the seed layer exposed due to the removal of the resist pattern is removed by etching. By doing so, for example, the pad portion 22 can be formed on the insulating layer 12, and the conductive connection portion 30 can be formed in the through opening portion 12A.

[0051] A plated film such as a Ni-Au plated film, an Au plated film, or the like can also be formed on the main surface 22A of the pad portion 22 formed in this step, for example, by an electroless plating method. In addition, for example, in order to realize the structures of the various modifications described later, after this step, a conductor layer including a predetermined pattern of a pad portion and / or a wiring layer can be formed on the surface of the thickness direction side of the insulating layer 12, a 3rd insulating layer of a predetermined pattern can be further formed so as to cover the conductor layer as a cover insulating layer, and a 3rd insulating layer can be formed in a stacked manner without the conductor layer.

[0052] For example, by the above-described steps, the wiring circuit board X can be manufactured.

[0053] As described above, the wiring circuit board X is provided with the pad portion 22 disposed on the thickness direction side of the insulating layer 12. The pad portion 22 is located on the insulating layer 12 (the boss portion 12B) whose surface on the thickness direction side is flat, and thus the pad portion 22 is easily formed as a pad portion having a flat main surface 22A. That is, the wiring circuit board X is suitable for ensuring the surface flatness of the pad portion 22.

[0054] Meanwhile, as described above, the wiring circuit board X is provided with the conductive connection portion 30 connected to at least a portion of the peripheral end portion 22a of the pad portion 22 and connected to the connection portion 21a of the wiring layer 21. In the wiring circuit board X, a wiring pattern on the insulating layer 12 for electrically connecting between the wiring layer 21 and the pad portion 22 is not required. In the wiring circuit board X in which the wiring layer 21 and the pad portion 22 can be electrically connected without providing such a wiring pattern on the insulating layer 12, the pad portion 22 is easily disposed at a high density. That is, the wiring circuit board X is suitable for realizing the high-density disposition of the pad portion 22.

[0055] As described above, the wiring circuit board X is suitable for ensuring the surface flatness of the pad portion 22 and realizing the high-density disposition of the pad portion 22.

[0056] In the wiring circuit board X, as described above, the through opening 12A of the insulating layer 12 is an opening along the entire circumference of the peripheral end portion 22a of the pad portion 22, and the conductive connection portion 30 is connected to the peripheral end portion 22a along the entire circumference of the peripheral end portion 22a. This structure is suitable for ensuring a large connection area between the pad portion 22 and the conductive connection portion 30, and therefore suitable for achieving high connection reliability.

[0057] In the wiring circuit board X, as described above, the opening end 12a of the through opening 12A of the insulating layer 12 includes an edge E1 that contacts the pad portion 22 and runs along the peripheral end portion 22a, and an edge E2 that exits the pad portion 22 and is opposite to the edge E1. The conductive connection portion 30 does not contact a part or the entire edge E2. This structure is suitable for further providing pad portions near the edge E2 of the through opening 12A on one side of the insulating layer 12 in the thickness direction, thus enabling a high-density arrangement of pad portions.

[0058] In the wiring circuit board X, as described above, the connection portion 21a of the wiring layer 21 closes the opening end 12b of the through opening 12A in the surface on the other side of the thickness direction of the insulating layer 12. This structure is suitable for ensuring a large connection area between the conductive connection portion 30 disposed in the through opening 12A and the wiring layer 21, and is therefore suitable for achieving high connection reliability.

[0059] like Figure 6 As shown in Figure A, the wiring circuit board X may also have a pad portion 23 (second pad portion) on one side of the insulating layer 12 in the thickness direction. The pad portion 23 is located away from the through opening 12A in the surface direction. The pad portion 23 has a main surface 23A for external connection, and is electrically connected to a portion of the wiring layer 21 via wiring (not shown) that is patterned on one side of the insulating layer 12 and connected to the pad portion 23, and via a through hole (not shown) that penetrates the insulating layer 12 and connects to the wiring. As a top view shape of the pad portion 23, rectangles such as circles and squares can be given. The thickness and material of the pad portion 23 are the same as those described above regarding the thickness and material of the pad portion 22.

[0060] Since the pad portion 22 and the pad portion 23 are provided on the surface of the insulating layer 12 on the thickness direction side, the pad portion 22 and the pad portion 23 are easily formed as pad portions having flat main surfaces 22A, 23A, and the difference in height (height from the insulating layer 12) of the main surfaces 22A, 23A is easily suppressed. According to such a structure, it is easy to appropriately mount an electronic component to the wiring circuit substrate X by means of the pad portions 22, 23. In a plurality of pad portions for mounting an electronic component provided in the wiring circuit substrate, the higher the surface flatness of each pad portion and the smaller the difference in height between the pad portions, the easier it is to appropriately mount an electronic component to the wiring circuit substrate by means of the plurality of pad portions.

[0061] As shown in Figure 6 The wiring circuit substrate X can also include, on the surface of the insulating layer 12 on the thickness direction side, an insulating layer 13 (a third insulating layer) that covers the insulating layer 12, as shown in Figure 6 In the modification example shown in

[0062] As shown in Figure 6 The wiring circuit substrate X can also include, on the surface of the insulating layer 12 on the thickness direction side, a wiring layer 24 (a second wiring layer) having a predetermined pattern shape and an insulating layer 13 that covers the insulating layer 12. The thickness, width, and material of the wiring layer 24 are the same as the above-described explanation regarding the thickness, width, and material of the wiring layer 21. The insulating layer 13 of the present modification example is provided on the surface of the insulating layer 12 on the thickness direction side so as to cover the wiring layer 24, and has an opening portion 13A that exposes the pad portion 22. The wiring circuit substrate X can have a multilayer wiring structure including the wiring layers 21, 24. The wiring circuit substrate X having a multilayer wiring structure is suitable for achieving a higher wiring density.

[0063] In the wiring circuit substrate X, for example, as shown in Figures 7 to 9 The through opening portion 12A of the insulating layer 12 can be opened along a part of the peripheral end portion 22a of the pad portion 22, the conductive connection portion 30 provided in the through opening portion 12A can be connected to a part of the peripheral end portion 22a of the pad portion 22, and the connection portion 21a of the wiring layer 21 can be connected to the conductive connection portion 30 Figure 7 A, Figure 8 A, and Figure 9 A is a partial cross-sectional view of each modification example, Figure 7 B,Figure 8 B and Figure 9 B is a partial top view of each variation example. Figure 7 C Figure 8 C and Figure 9 C is a partial cross-sectional view of each variant (with a portion omitted). In such a variant, the pad portion 22 is also located on the insulating layer 12, thus it is easy to ensure the surface flatness of the pad portion 22, and there is no need for wiring patterns on the insulating layer 12 for electrical connection between the pad portion 22 and the wiring layer 21, thus it is easy to achieve a high-density configuration of the pad portion 22.

[0064] exist Figure 7 In the modified example shown, the pad portion 22 is disposed on the same side as the wiring layer 21 in the planar direction relative to the conductive connection portion 30 connected to the pad portion 22 and the wiring layer 21. This structure is suitable for distributing other pad portions close to the pad portion 22 in a region on the insulating layer 12 on the side opposite to the wiring layer 21 in the planar direction relative to the conductive connection portion 30. Therefore, it is suitable to achieve a high density of pad portion configuration in the wiring circuit board X.

[0065] exist Figure 8 In the modified example shown, the pad portion 22 is disposed on the side opposite to the wiring layer 21 in the planar direction, relative to the conductive connection portion 30 connected to the pad portion 22 and the wiring layer 21. This structure is suitable for distributing other pad portions close to the pad portion 22 in a region on the insulating layer 12 on the same side in the planar direction as the wiring layer 21 relative to the conductive connection portion 30. Therefore, it is suitable to achieve a high density of pad portion configuration in the wiring circuit board X.

[0066] exist Figure 9 In the modified example shown, the conductive connection portion 30, when viewed by projection in the thickness direction, has a shape that extends from the connection portion 21a of the wiring layer 21 to the peripheral end portion 22a of the pad portion 22. Such a structure is suitable for ensuring a large connection area between the pad portion 22 and the conductive connection portion 30, and therefore is suitable for achieving high connection reliability.

[0067] exist Figures 7 to 9 In the various modifications shown, the conductive connection portion 30 preferably does not contact a portion or the entire edge E2 of the opening end 12a of the through opening portion 12A (the case where the conductive connection portion 30 does not contact the entire edge E2 is illustrated in the illustration). Such a structure is suitable for further providing pad portions near the edge E2 of the through opening portion 12A on the thickness direction side of the insulating layer 12, thus enabling a high density of pad portion configuration.

[0068] Industrial availability

[0069] The wiring circuit substrate of the present application can be applied to various flexible wiring circuit substrates and rigid wiring circuit substrates.

[0070] BRIEF DESCRIPTION OF DRAWINGS

[0071] X, wiring circuit substrate; S, base material; 11, 12, 13, insulating layer; 12A, through opening portion; 12B, boss portion; 12a, 12b, opening end; E1, E2, edge; 21, 24, wiring layer; 21a, connection portion; 22, 23, land portion; 22A, main surface; 22a, peripheral end portion; 30, conductive communication portion.

Claims

1. A wiring circuit board, characterized in that, The wiring circuit board includes: First insulating layer; A wiring layer disposed on one side of the first insulating layer in the thickness direction; A second insulating layer is disposed on one side of the first insulating layer in the thickness direction such that it covers the wiring layer; The pad portion is disposed on one side of the second insulating layer in the thickness direction; and The conductive interconnect connects the wiring layer to the pad portion. The second insulating layer has a through opening that extends through the second insulating layer in the thickness direction and opens along at least a portion of the peripheral end of the pad portion. The wiring layer has a connection portion facing the through opening. The conductive connection portion is disposed in the through opening, connected to at least a portion of the peripheral end of the pad portion, and connected to the connection portion of the wiring layer. The inner circumferential surface of the through opening has a first opening end on one side in the thickness direction and a second opening end on the other side in the thickness direction. The inner circumferential surface of the through opening has a conical shape that slopes outwards from the second opening end toward the first opening end. The second insulating layer includes a boss portion surrounded by the through opening. The peripheral surface of the boss portion has a conical shape that slopes inward as it moves from one end toward the other.

2. The wiring circuit board according to claim 1, characterized in that, The second opening end is disposed at a distance from the other end of the peripheral side surface of the boss portion. The conductive connection portion is configured to contact the peripheral side surface of the boss portion, and the connection portion between the other end of the boss portion and the second opening end.

3. The wiring circuit board according to claim 1, characterized in that, When viewed by projection in the thickness direction, the conductive connection portion has a shape that extends from the connection portion of the wiring layer to the peripheral end portion of the pad portion.

4. The wiring circuit board according to claim 1, characterized in that, The opening end of the through opening in the face on one side of the thickness direction of the second insulating layer includes a first edge that contacts the pad portion and runs along the circumferential end portion and a second edge that leaves the pad portion and is opposite to the first edge, wherein the conductive connection portion does not contact a part or the entirety of the second edge.

5. The wiring circuit board according to claim 1, characterized in that, The connection portion of the wiring layer closes the opening end of the through opening in the surface on the other side of the thickness direction of the second insulating layer.

Images