Manufacturing method of wiring boards

Abstract

To prevent infiltration of liquid from a side face of a support in a wiring board manufacturing process.SOLUTION: The present method for manufacturing a wiring board includes the steps of: preparing a support in which a metal foil including a first foil and a second foil stacked on the first foil with a release layer therebetween is stacked on a surface of a substrate with the first foil directed toward the substrate; and forming a wiring board on the support. A wiring board forming area and a frame-like outer peripheral area located on an outer peripheral side of the wiring board forming area are defined on the support in plan view. The step of forming the wiring board includes the steps of: forming, in the outer peripheral area, a recess that penetrates the second foil in a thickness direction and has a frame shape in plan view; selectively forming a first wiring layer on the second foil, and forming a frame-like outer peripheral metal layer for filling the recess; forming an insulating layer covering the first wiring layer and the outer peripheral metal layer on the second foil; forming a second wiring layer on the insulating layer located in the wiring board forming area; removing the outer peripheral area; and removing the support.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a wiring board.

Background Art

[0002] Conventionally, a method for manufacturing a wiring board in which wiring layers and insulating layers are alternately laminated by a build-up method is known. For example, a support having a thick foil and a thin foil laminated on a substrate is prepared, and the wiring layers and the insulating layers are alternately laminated on the upper surface of the metal foil. In this support, a wiring board formation region and a frame-shaped outer peripheral region located on the outer peripheral side of the wiring board formation region are defined in a plan view. After alternately laminating the wiring layers and the insulating layers on the upper surface of the metal foil, the thick foil and the substrate are removed by peeling at the interface between the thick foil and the thin foil, and then the thin foil is removed by etching to complete the wiring board (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the support as described above, the ends of the metal foil (the ends of the thick foil and the thin foil) are exposed on the side surface of the support. Therefore, in the manufacturing process of the wiring board, the plating solution in the plating process or the etching solution in the etching process may penetrate into the interface between the thick foil and the thin foil exposed on the side surface of the support, causing unexpected peeling between the thick foil and the thin foil during the manufacturing process.

[0005] The present invention has been made in view of the above points, and an object thereof is to suppress liquid intrusion from the side surface of the support in the manufacturing process of the wiring board.

Means for Solving the Problems

[0006] The present method for manufacturing a wiring board includes the steps of: preparing a support on the surface of a substrate in which a metal foil comprising a first foil and a second foil laminated on the first foil with a release layer in between is laminated with the first foil facing the substrate side; forming a wiring board on the support, wherein the support is defined in plan view as a wiring board forming region and a frame-shaped outer peripheral region located on the outer periphery of the wiring board forming region, and the step of forming the wiring board includes the steps of: forming a frame-shaped recess in the outer peripheral region that penetrates the second foil in the thickness direction in plan view; selectively forming a first wiring layer on the second foil and forming a frame-shaped outer peripheral metal layer that fills the recess; forming an insulating layer on the second foil that covers the first wiring layer and the outer peripheral metal layer; forming a second wiring layer on the insulating layer located in the wiring board forming region; removing the outer peripheral region; and removing the support. [Effects of the Invention]

[0007] According to the disclosed technology, it is possible to suppress liquid intrusion from the side of the support during the manufacturing process of a wiring board. [Brief explanation of the drawing]

[0008] [Figure 1] This is a cross-sectional view illustrating a wiring board according to the first embodiment. [Figure 2] This is a diagram (part 1) illustrating the manufacturing process of a wiring board according to the first embodiment. [Figure 3] This is a diagram (part 2) illustrating the manufacturing process of a wiring board according to the first embodiment. [Figure 4] This is a diagram (part 3) illustrating the manufacturing process of a wiring board according to the first embodiment. [Figure 5] This is a diagram (part 4) illustrating the manufacturing process of a wiring board according to the first embodiment. [Figure 6] This is a diagram (part 5) illustrating the manufacturing process of a wiring board according to the first embodiment. [Figure 7] This figure illustrates the manufacturing process of a wiring board according to Modification 1 of the First Embodiment. [Modes for carrying out the invention]

[0009] The embodiments for carrying out the invention will be described below with reference to the drawings. In each drawing, the same reference numerals are used for identical components, and redundant explanations may be omitted.

[0010] <First Embodiment> [Structure of a wiring board] Figure 1 is a cross-sectional view illustrating a wiring board according to the first embodiment. Referring to Figure 1, the wiring board 1 is a coreless build-up wiring board having a first wiring layer 10, an insulating layer 20, a second wiring layer 30, and a solder resist layer 40. The solder resist layer 40 can be provided as needed. Furthermore, the wiring board 1 may have multiple insulating layers and wiring layers.

[0011] In this embodiment, for convenience, the solder resist layer 40 side of the wiring board 1 in Figure 1 is referred to as the upper side or one side, and the first wiring layer 10 side as the lower side or the other side. Also, the surface of each part facing the solder resist layer 40 is referred to as one surface or the upper surface, and the surface facing the first wiring layer 10 is referred to as the other surface or the lower surface. However, the wiring board 1 can be used upside down or positioned at any angle. Furthermore, a plan view refers to viewing the object from the direction normal to one surface of the solder resist layer 40, and a planar shape refers to the shape of the object viewed from the direction normal to one surface of the solder resist layer 40.

[0012] In the wiring board 1, the first wiring layer 10 is embedded on the lower side of the insulating layer 20. The lower surface of the first wiring layer 10 is exposed from the lower surface of the insulating layer 20, while the upper and side surfaces of the first wiring layer 10 are covered by the insulating layer 20. The lower surface of the first wiring layer 10 can be flush with the lower surface of the insulating layer 20, for example.

[0013] The lower surface of the first wiring layer 10, which is exposed from the lower surface of the insulating layer 20, can be formed in a circular shape, for example, and used as a pad for connection to other wiring boards, etc. The first wiring layer 10 may also have a wiring pattern in addition to the pad. For example, copper (Cu) can be used as the material for the first wiring layer 10. The first wiring layer 10 may also have a laminated structure of multiple metal layers. The thickness of the first wiring layer 10 can be, for example, about 10 to 20 μm.

[0014] The insulating layer 20 is formed to cover the upper and side surfaces of the first wiring layer 10. As the material for the insulating layer 20, for example, a non-photosensitive (thermosetting resin) epoxy insulating resin or polyimide insulating resin can be used. Alternatively, a photosensitive epoxy insulating resin or acrylic insulating resin may be used as the material for the insulating layer 20. The thickness of the insulating layer 20 can be, for example, about 20 to 40 μm. The insulating layer 20 may contain fillers such as silica (SiO2).

[0015] The second wiring layer 30 is formed on the insulating layer 20. The second wiring layer 30 consists of via wiring filled in via holes 20x that penetrate the insulating layer 20 and expose the upper surface of the first wiring layer 10, and a wiring pattern formed on the upper surface of the insulating layer 20. The via holes 20x can be inverted truncated cone-shaped recesses in which the diameter of the opening that opens to the solder resist layer 40 side is larger than the diameter of the bottom surface of the opening formed by the upper surface of the first wiring layer 10. Via wiring is also formed within these recesses. The second wiring layer 30 is electrically connected to the first wiring layer 10 exposed at the bottom of the via holes 20x. The thickness of the wiring pattern constituting the second wiring layer 30 can be, for example, about 10 to 20 μm.

[0016] The second wiring layer 30 can have a structure including, for example, a first metal layer 31, a second metal layer 32, and a third metal layer 33. The first metal layer 31 can be provided, for example, on the upper surface of the insulating layer 20 so as to surround the via hole 20x in a plan view. The second metal layer 32 can be provided, for example, so as to continuously cover the upper surface of the first metal layer 31, the inner surface of the via hole 20x, and the upper surface of the first wiring layer 10 exposed within the via hole 20x. Note that the inner surface of the via hole 20x includes the inner surface of the first metal layer 31 and the inner surface of the insulating layer 20.

[0017] The third metal layer 33 can be provided, for example, on the second metal layer 32. The third metal layer 33 fills the via hole 20x, for example, and extends from within the via hole 20x to cover the upper surface of the second metal layer 32. The upper surface of the third metal layer 33 is substantially flat. The first metal layer 31, the second metal layer 32, and the third metal layer 33 can be formed of, for example, copper, but they may each be formed of different metals.

[0018] The solder resist layer 40 is formed on the insulating layer 20 so as to cover the second wiring layer 30. As the material of the solder resist layer 40, for example, a photosensitive insulating resin mainly composed of a phenolic resin, a polyimide resin, or the like can be used. The solder resist layer 40 may contain a filler such as silica (SiO2). The solder resist layer 40 has an opening 40x, and a part of the second wiring layer 30 is exposed within the opening 40x. The second wiring layer 30 exposed at the bottom of the opening 40x can be used as a pad to be connected to a semiconductor chip or the like.

[0019] Note that a surface treatment layer (not shown) may be formed on the upper surface of the second wiring layer 30 exposed at the bottom of the opening 40x. Examples of the surface treatment layer include an Au layer, a Ni / Au layer (a metal layer formed by laminating a Ni layer and an Au layer in this order), a Ni / Pd / Au layer (a metal layer formed by laminating a Ni layer, a Pd layer, and an Au layer in this order), and the like. Alternatively, an antioxidant treatment such as OSP (Organic Solderability Preservative) treatment may be performed on the upper surface of the second wiring layer 30 exposed at the bottom of the opening 40x to form a surface treatment layer.

[0020] [Method for manufacturing a wiring board] Next, a method for manufacturing a wiring board according to the first embodiment will be described. FIGS. 2 to 6 are diagrams illustrating the manufacturing process of the wiring board according to the first embodiment. FIGS. 2(c) and 3(b) are plan views, and the others are cross-sectional views. Note that the wiring board may be formed on only one surface of the support, but here, an example in which the wiring board is formed on both surfaces (upper and lower sides) of the support is shown. In this example, since the wiring boards are formed symmetrically on the upper and lower sides of the support, the indication of the reference numerals on the lower side of the support is omitted in each cross-sectional view.

[0021] First, in the process shown in FIGS. 2(a) to 2(c), a metal foil 520 including a thick foil 521 (carrier foil) and a thin foil 522 laminated on the thick foil 521 via a release layer is prepared on both surfaces of a substrate 510, with the thick foil 521 facing the substrate 510 side, to form a support 500. As an example of the release layer between the thick foil 521 and the thin foil 522, a metal oxide film, an organic layer, or the like can be used.

[0022] Specifically, as shown in Figure 2(a), first, one substrate 510 and two metal foils 520 are prepared. The substrate 510 and the metal foils 520 are, for example, of similar size in a plan view. The substrate 510 is a semi-cured (B-stage) prepreg made by impregnating a thermosetting resin such as epoxy resin or polyimide resin into, for example, glass cloth (woven fabric), glass nonwoven fabric, or aramid fibers. The thickness of the substrate 510 can be, for example, about 18 to 100 μm. The metal foils 520 are made by peeling off a thin foil 522, made of a metal foil such as copper, with a thickness of about 1.5 to 5 μm, on top of a thick foil 521, made of a metal foil such as copper, with a thickness of about 10 to 50 μm. In this way, the thickness of the thin foil 522 is thinner than the thickness of the thick foil 521. Note that "thick foil" and "thin foil" are names used to indicate the relative thickness relationship between them.

[0023] Next, as shown in Figure 2(b), each metal foil 520 is placed on the upper and lower surfaces of the base body 510 such that the thick foil 521 faces the base body 510. Then, while heating the base body 510, each metal foil 520 is pressed toward the base body 510 to harden the base body 510 and form the support body 500. Note that the support body 500 may be prepared by purchase or other means rather than being manufactured by the manufacturer.

[0024] As shown in Figure 2(c), the support 500 has a wiring board formation region C and a frame-shaped outer peripheral region D located on the outer periphery of the wiring board formation region C in a plan view. The width of the outer peripheral region D can be, for example, about 1 mm to 3 mm. The wiring board formation region C may include a plurality of individualization regions R that become wiring boards 1 when individualized. The individualization regions R can be arranged in a matrix in a two-dimensional manner in a plan view, for example. In the example in Figure 2(c), the individualization regions R are arranged in a matrix of 3 rows x 6 columns, but are not limited to this.

[0025] Figures 2(a) and 2(b) show cross-sections along line AA in Figure 2(c). However, the dashed portion of line AA is omitted from the illustration, and only the dashed-dotted portion is shown. In other words, one segmented region R located on line AA and the outer peripheral region D located on line AA are shown. The same applies to subsequent cross-sectional diagrams.

[0026] Furthermore, if the wiring board is to be formed on only one side of the support, a support can be prepared in which a metal foil 520, including a thick foil 521 and a thin foil 522 laminated on the thick foil 521 with a release layer in between, is laminated on at least one side of the base body 510, with the thick foil 521 facing the base body 510.

[0027] Next, a wiring board 1 is formed on the support 500. Figures 3 to 6 show the process of forming the wiring board 1 on both sides of the support 500. First, in the process shown in Figures 3(a) and 3(b), recesses 522x are formed in the outer peripheral regions D on the upper and lower sides of the support 500, penetrating the thin foil 522 in the thickness direction and exposing the surface of the thick foil 521. The recesses 522x are formed in a frame shape in plan view, surrounding the outer edge of the wiring formation region C. In Figure 3(b), the area where the recesses 522x are formed and the surface of the thick foil 521 is exposed within the recesses 522x is shown by a dot pattern for convenience. The recesses 522x are formed, for example, inside the outermost periphery of the support 500. The recesses 522x can be formed, for example, by partially removing the thin foil 522 by a laser processing method. A part of the thick foil 521 may also be removed by the laser processing method. The width of the recesses 522x can be, for example, about 20 μm to 100 μm. The recessed portion 522x may be formed by blasting, etching, or other methods.

[0028] Furthermore, by forming the recess 522x inward from the outermost periphery of the support 500, the following effects can be obtained. There will be some variation in the planar shape and size of the substrate 510 and the metal foil 520. Therefore, there will also be some variation in the planar shape and size of the support 500 formed by laminating the substrate 510 and the metal foil 520. If the recess 522x is formed on the outermost periphery of the support 500, the width of the recess 522x will also vary due to the variation in the planar shape and size of the support 500. Due to this variation, it may not be possible to obtain a recess 522x with a width sufficient to prevent liquid from entering the support 500 from the sides. In contrast, by forming the recess 522x inward from the outermost periphery of the support 500, it is possible to form a recess 522x with a stable width. Therefore, it is possible to stably obtain a recess 522x with a width sufficient to prevent liquid from entering the support 500 from the sides.

[0029] Next, in the process shown in Figure 3(c), a resist layer 530 is formed on the thin foil 522 located in the wiring substrate formation region C and the outer peripheral region D on the upper and lower sides of the support 500. Then, openings 530x are formed in the resist layer 530 that selectively expose the thin foil 522 located in the wiring substrate formation region C and the outer peripheral region D. The resist layer 530 can be formed using, for example, a photosensitive dry film resist or a liquid resist. The openings 530x can be formed by exposing and developing the resist layer 530. The openings 530x are formed at the locations where the first wiring layer 10 and the outer peripheral metal layer 600 are to be formed. That is, the openings 530x are formed to expose the recesses 522x.

[0030] Next, in the process shown in Figure 4(a), the first wiring layer 10 is selectively formed on the thin foil 522 located in the wiring substrate formation region C on the upper and lower sides of the support 500, and a frame-shaped outer peripheral metal layer 600 that fills the recesses 522x is formed on the thin foil 522 located in the outer peripheral region D. For example, the outer peripheral metal layer 600 is formed by filling the recesses 522x. Alternatively, the outer peripheral metal layer 600 is formed in contact with the surface of the thick foil 521 exposed in the recesses 522x. The outer peripheral metal layer 600 fills the recesses 522x and may also be extended to the inside and outside of the recesses 522x in a plan view. The first wiring layer 10 and the outer peripheral metal layer 600 can be formed on the thin foil 522 exposed in the opening 530x by an electroplating method using metal foil 520 (thick foil 521 and thin foil 522) as a power supply layer. The outer metal layer 600 can be formed from the same material as the first wiring layer 10 and to the same thickness as the first wiring layer 10. The first wiring layer 10 and the outer metal layer 600 can be formed from, for example, copper.

[0031] Next, in the step shown in Figure 4(b), the resist layer 530 is removed using a resist stripping solution. Then, in the step shown in Figure 4(c), an insulating layer 20 is formed on the thin foil 522 located in the wiring substrate formation region C and the outer peripheral region D on the upper and lower sides of the support 500, covering the first wiring layer 10 and the outer peripheral metal layer 600. Specifically, for example, the insulating layer 20 can be formed by placing a prepreg in a semi-cured state (B-stage) similar to the substrate 510 so as to cover the first wiring layer 10 and the outer peripheral metal layer 600, and then heating and curing the prepreg while applying pressure to the support 500 side.

[0032] In this process, an insulating layer 20 on which the first metal layer 31 is laminated may be formed. In this case, a prepreg in a semi-cured state (B-stage) similar to the substrate 510 and a metal foil similar to the metal foil 520 are prepared. Then, the thin foil constituting the metal foil is facing the prepreg and the metal foil is laminated onto the prepreg. Then, the metal foil and prepreg are heated while applying pressure towards the support 500 to cure the prepreg. Finally, the first metal layer 31 consisting of thin foil can be formed by peeling off the thick foil constituting the metal foil.

[0033] In this way, by forming an insulating layer 20 with the first metal layer 31 laminated on it, the following effects can be obtained. Generally, when comparing the adhesion strength (peel strength) of the electroless plating layer to the insulating layer when an electroless plating layer is formed on the surface of the insulating layer, with the adhesion strength (peel strength) of the metal foil to the insulating layer when a metal foil is laminated on the surface of the insulating layer, the adhesion strength of the metal foil is greater. Therefore, when the first metal layer 31 is laminated on the insulating layer 20, and then the second metal layer 32 (electroless plating layer) and the third metal layer 33 (electroplating layer) are laminated on the first metal layer 31 to form the second wiring layer 30, the second wiring layer 30 can be firmly adhered to the insulating layer 20. In other words, the peel strength of the second wiring layer 30 to the insulating layer 20 can be improved. The following describes an example of when the first metal layer 31 is laminated on the insulating layer 20.

[0034] Next, in the steps shown in Figure 4(d) to Figure 5(d), a second wiring layer 30 is formed on the insulating layer 20 located in the wiring substrate formation region C on the upper and lower surfaces of the support 500 by a plating method.

[0035] First, in the process shown in Figure 4(d), via holes 20x are formed on the upper and lower sides of the support 500, penetrating the first metal layer 31 and the insulating layer 20, and exposing the upper surface of the first wiring layer 10. The via holes 20x can be formed by a laser processing method, for example, using a CO2 laser. The via holes 20x can be in the shape of an inverted frustoconical recess, where the diameter of the opening on the side where the solder resist layer 40 is formed is larger than the diameter of the bottom surface of the opening formed by the upper surface of the first wiring layer 10. After forming the via holes 20x, it is preferable to perform a desmear treatment to remove resin residue adhering to the surface of the first wiring layer 10 exposed at the bottom of the via holes 20x.

[0036] Next, in the process shown in Figure 5(a), a second metal layer 32 is formed on the upper and lower sides of the support 500, continuously covering the upper surface of the first metal layer 31, the inner surface of the via holes 20x, and the upper surface of the first wiring layer 10 exposed within the via holes 20x. The second metal layer 32 can be formed, for example, by electroless copper plating or copper sputtering. The thickness of the second metal layer 32 can be, for example, about 200 to 400 nm. Next, a resist layer 540 having openings 540x that match the shape of the wiring pattern of the second wiring layer 30 is formed on the second metal layer 32. The resist layer 540 and the openings 540x can be formed, for example, by the same method as the resist layer 530 and the openings 530x.

[0037] Next, in the step shown in Figure 5(b), a third metal layer 33 is selectively formed on the second metal layer 32 exposed within the opening 540x by an electroplating method using the second metal layer 32 as the power supply layer on the upper and lower sides of the support 500. Next, in the step shown in Figure 5(c), the resist layer 540 is removed on the upper and lower sides of the support 500 using a resist stripping solution. Next, in the step shown in Figure 5(d), the first metal layer 31 and the second metal layer 32 exposed from the third metal layer 33 are removed by etching on the upper and lower sides of the support 500 to form a second wiring layer 30 comprising the first metal layer 31, the second metal layer 32, and the third metal layer 33.

[0038] Next, in the process shown in Figure 6(a), a solder resist layer 40 is formed on the upper and lower surfaces of the support 500 so as to cover the second wiring layer 30 on the insulating layer 20. The solder resist layer 40 can be formed, for example, by applying a liquid or paste-like photosensitive epoxy insulating resin or acrylic insulating resin to the surface of the insulating layer 20 using a screen printing method, roll coating method, or spin coating method so as to cover the second wiring layer 30. Alternatively, it may be formed, for example, by laminating a film-like photosensitive epoxy insulating resin or acrylic insulating resin to the surface of the insulating layer 20 so as to cover the second wiring layer 30. Next, the solder resist layer 40 is exposed and developed to form an opening 40x in the solder resist layer 40 that exposes a part of the upper surface of the second wiring layer 30 (photolithography method).

[0039] Furthermore, the aforementioned metal layer may be formed on the second wiring layer 30 exposed at the bottom of the opening 40x by, for example, electroless plating. Alternatively, instead of forming a metal layer, an anti-oxidation treatment such as OSP treatment may be applied.

[0040] Next, in the step shown in Figure 6(b), the outer peripheral region D is removed from the structure shown in Figure 6(a), and the wiring board formation region C is separated into individual pieces. That is, the structure shown in Figure 6(a) is cut along the dashed-dotted line that defines the individualized region R shown in Figure 2(c), and each individualized region R is separated individually. The cutting can be done, for example, using a slicer. Regarding the cutting between the outer peripheral region D and the wiring board formation region C, the specific cutting location is, for example, between the recess 522x and the wiring board formation region C. In other words, the step of removing the outer peripheral region D includes cutting between the recess 522x and the wiring board formation region C.

[0041] Next, in the steps shown in Figures 6(c) and 6(d), the support 500 is removed from the structure shown in Figure 6(b) to complete the wiring board 1. First, in the step shown in Figure 6(c), the thick foil 521 and the thin foil 522 are separated from the upper and lower surfaces of the support 500. Since the adhesive force between the thick foil 521 and the thin foil 522 is weak, the thick foil 521 and the thin foil 522 can be easily separated mechanically.

[0042] Next, in the step shown in Figure 6(d), the thin foil 522 is removed by etching. If the thin foil 522 is copper, it can be removed by wet etching using, for example, an aqueous solution of ferric chloride, an aqueous solution of cupric chloride, or an aqueous solution of ammonium persulfate. Through the above steps, multiple individualized wiring boards 1 can be obtained. Alternatively, in the structure shown in Figure 6(a), the outer peripheral region D and the wiring board formation region C may be cut, then the thick foil 521 and the thin foil 522 are separated, the thick foil 521 and the substrate 510 are removed, then the thin foil 522 is removed by etching, and then cuts are made along the dashed lines defining each individualized region R to obtain the wiring board 1.

[0043] Furthermore, after the process shown in Figure 5(d), the same process as shown in Figures 4(c) to 5(d) may be repeated as many times as necessary to laminate the insulating layer and wiring layer in multiple layers.

[0044] In this way, in the manufacturing method of the wiring board 1, a frame-shaped recess 522x is formed in the outer peripheral region D in a plan view, and a frame-shaped outer peripheral metal layer 600 is formed to fill the recess 522x. Therefore, in the process after the formation of the outer peripheral metal layer 600, even if a plating solution or etching solution tries to penetrate the interface between the thick foil 521 and the thin foil 522 exposed on the side surface of the support 500, it is blocked by the outer peripheral metal layer 600 that fills the recess 522x. This makes it possible to suppress the occurrence of unexpected delamination between the thick foil 521 and the thin foil 522 during the manufacturing process of the wiring board 1.

[0045] Furthermore, since the outer metal layer 600 can be formed simultaneously with the first wiring layer 10 by an electroplating method using the metal foil 520 as the power supply layer, no special effort is required to form the outer metal layer 600. Also, since the outer metal layer 600 has the same thickness as the first wiring layer 10, a sufficient effect of preventing liquid intrusion is obtained.

[0046] The processes in which the outer metal layer 600 exhibits the effect of suppressing liquid penetration include, for example, the process of forming the second metal layer 32 and the third metal layer 33 that constitute the second wiring layer 30 by a plating method, and the process of removing the first metal layer 31 and the second metal layer 32 exposed from the third metal layer 33 by etching.

[0047] <Variation 1 of the First Embodiment> Modification 1 of the first embodiment shows an example in which the position of the recess formed in the outer peripheral region of the support differs from that of the first embodiment. In Modification 1 of the first embodiment, descriptions of components that are the same as those described in the previously described embodiments may be omitted.

[0048] Figure 7 illustrates the manufacturing process of a wiring board according to Modification 1 of the First Embodiment. The steps shown in Figures 7(a) and 7(b) may be used instead of the steps shown in Figures 3(a) and 3(b) of the First Embodiment.

[0049] That is, as shown in Figures 7(a) and 7(b), the recesses 522x formed in the outer peripheral regions D on the upper and lower sides of the support 500 may be formed on the outermost periphery of the support 500. The other steps are the same as in the first embodiment, so that multiple wiring boards 1 can be manufactured in the same way as in the first embodiment. In Figure 7(b), for convenience, the areas where the recesses 522x are formed and the surface of the thick foil 521 is exposed within the recesses 522x are shown with a dot pattern.

[0050] Furthermore, when comparing the case where the recess 522x is formed inward from the outermost periphery of the support 500 with the case where the recess 522x is formed on the outermost periphery of the support 500, the width of the outer peripheral region D can be narrowed when the recess 522x is formed on the outermost periphery of the support 500. Consequently, the area of ​​the wiring board formation region C can be increased, making it possible to increase the number of wiring boards 1 that can be obtained.

[0051] In the case of Modification 1 of the First Embodiment, as shown in Figure 7(c), by forming a frame-shaped outer peripheral metal layer 600 that fills the recess 522x, liquid intrusion into the interface between the thick foil 521 and the thin foil 522 exposed on the side surface of the support 500 can be suppressed, similar to the First Embodiment. This makes it possible to suppress the occurrence of unexpected delamination between the thick foil 521 and the thin foil 522 during the manufacturing process of the wiring board 1.

[0052] Although preferred embodiments have been described in detail above, the invention is not limited to the embodiments described above, and various modifications and substitutions can be made to the embodiments described above without departing from the scope of the claims. [Explanation of symbols]

[0053] 1 Wiring board 10 1st wiring layer 20 Insulating layer 20x Beer Hall 30 2nd wiring layer 31 1st metal layer 32 Second metal layer 33 Third metal layer 40 solder resist layers 40x opening 500 support 510 Base 520 Metal Foil 521 Thick foil 522 Thin foil 522x recess 530,540 resist layers 530x,540x opening 600 Outer metal layer

Claims

1. A step of preparing a support in which a metal foil, including a first foil and a second foil laminated on the first foil with a release layer in between, is laminated on the surface of a substrate, with the first foil facing the substrate side, The process includes forming a wiring board on the support, The support has, in a plan view, a wiring board formation region and a frame-shaped outer peripheral region located on the outer periphery side of the wiring board formation region. The process of forming the aforementioned wiring board is as follows: The process of forming a frame-shaped recess in the outer peripheral region, which penetrates the second foil in the thickness direction, in a plan view, A step of selectively forming a first wiring layer on the second foil and forming a frame-shaped outer metal layer that fills the recesses, A step of forming an insulating layer on the second foil that covers the first wiring layer and the outer peripheral metal layer, A step of forming a second wiring layer on the insulating layer located in the wiring board formation region, The step of removing the outer peripheral region, A method for manufacturing a wiring board, comprising the step of removing the support mentioned above.

2. The method for manufacturing a wiring substrate according to claim 1, wherein the outer peripheral metal layer is formed using the same material as the first wiring layer by an electroplating method with the metal foil as the power supply layer.

3. The method for manufacturing a wiring substrate according to claim 2, wherein the outer peripheral metal layer has the same thickness as the first wiring layer.

4. A method for manufacturing a wiring board according to claim 1, wherein the recess is formed by a laser processing method.

5. The method for manufacturing a wiring board according to any one of claims 1 to 4, wherein the recess is formed inward from the outermost periphery of the support.

6. The method for manufacturing a wiring board according to any one of claims 1 to 4, wherein the recess is formed on the outermost periphery of the support.

7. In the step of forming the insulating layer, a first metal layer is laminated on the insulating layer. The step of forming the second wiring layer includes the step of forming via holes that penetrate the first metal layer and the insulating layer and expose the upper surface of the first wiring layer, A step of forming a second metal layer that continuously covers the upper surface of the first metal layer, the inner surface of the via hole, and the upper surface of the first wiring layer exposed within the via hole, A step of selectively forming a third metal layer on the second metal layer by an electroplating method using the second metal layer as a power supply layer, A method for manufacturing a wiring substrate according to any one of claims 1 to 4, comprising the step of removing the first metal layer and the second metal layer exposed from the third metal layer by etching to form the second wiring layer comprising the first metal layer, the second metal layer and the third metal layer.

8. A method for manufacturing a wiring substrate according to any one of claims 1 to 4, wherein, in the step of forming the first wiring layer and the outer peripheral metal layer, the first foil is exposed in the recess and the outer peripheral metal layer is in contact with the first foil exposed in the recess.

9. The method for manufacturing a wiring board according to any one of claims 1 to 4, wherein the step of removing the outer peripheral region includes cutting between the recess and the wiring board forming region.

10. The method for manufacturing a wiring board according to any one of claims 1 to 4, wherein the wiring board forming region includes a plurality of individualized regions that will become the wiring board, and the method comprises a step of separating each of the individualized regions individually.

Images