JP7423326B2 - Printed wiring board and method for manufacturing printed wiring board - Google Patents

Description

The present disclosure relates to a printed wiring board and a method of manufacturing the printed wiring board.

Conventionally, there are printed wiring boards having multiple circuit layers separated by insulating layers. In addition, the outer layer circuit formed on the surface of this printed wiring board and the inner layer circuit formed inside are electrically connected by vias, and the outer layer circuits on both sides are connected by through holes that penetrate the entire printed wiring board. A technique for forming a three-dimensional circuit by electrically connecting two is known (for example, Patent Document 1).

Japanese Patent Application Publication No. 2017-135357

A printed wiring board according to one aspect of the present disclosure,
A printed wiring board comprising an insulating layer and a conductor part,
The insulating layer has an opening formed in a direction perpendicular to the first surface of the insulating layer,
The conductor portion includes a connection conductor provided to fill at least a portion of the opening , and a conductor layer located on the first surface ,
The opening has a step portion in which the diameter of the second opening on the second surface side of the insulating layer is smaller than the diameter of the first opening on the first surface,
The connection conductor is provided so as to fill the step portion and is connected to the conductor layer .

Further, a method for manufacturing a printed wiring board according to another aspect of the present disclosure includes:
an opening forming step of forming an opening in a direction perpendicular to the first surface of the insulating layer;
a connecting conductor forming step of forming a connecting conductor so as to fill at least a portion of the opening,
In the opening forming step, the opening has a step shape in which the diameter of the second opening on the second surface side of the insulating layer is smaller than the diameter of the first opening on the first surface,
In the connection conductor forming step, the connection conductor is formed so as to fill the stepped portion,
The opening forming step includes:
removing the metal foil previously formed on the first surface by a subtractive method;
forming the stepped portion by partially removing a portion of the insulating layer using a laser or a drill;
including .

FIG. 2 is a cross-sectional view of a printed wiring board. FIG. 2 is an enlarged view showing the periphery of a first connection conductor in FIG. 1; FIG. 2 is an enlarged view showing the periphery of a second connection conductor in FIG. 1; FIG. 3 is a cross-sectional view illustrating a method for manufacturing a printed wiring board. FIG. 3 is a cross-sectional view illustrating a method for manufacturing a printed wiring board. FIG. 3 is a cross-sectional view illustrating a method for manufacturing a printed wiring board. FIG. 3 is a cross-sectional view showing Modification 1 of the printed wiring board. FIG. 7 is a sectional view showing a second modification of the printed wiring board.

Hereinafter, embodiments will be described based on the drawings. However, the dimensions of the members in each figure do not faithfully represent the dimensions and dimensional ratios of the actual constituent members.

[Configuration of printed wiring board]
FIG. 1 is a cross-sectional view of a printed wiring board 1 according to this embodiment.
Printed wiring board 1 includes a conductor section 100 and an insulating layer 200. In the insulating layer 200, the second surface S2 is a surface located on the opposite side of the first surface S1. In addition, from another point of view, the printed wiring board 1 includes a core layer R1 and buildup layers R2 provided on the front and back sides of the core layer R1, respectively. The core layer R1 consists of a part of the conductor part 100 and a part of the insulating layer 200, and the buildup layer R2 consists of a part of the conductor part 100 and a part of the insulating layer 200.
In the following, the orientation of each part of the printed wiring board 1 will be explained using an XYZ orthogonal coordinate system in which the thickness direction of the printed wiring board 1 is the Z direction. The first surface S1 and the second surface S2 of the insulating layer 200 of the printed wiring board 1 are parallel to the XY plane. FIG. 1 is a diagram showing a cross section of printed wiring board 1 perpendicular to the Y direction. Hereinafter, the surface facing the +Z direction of each layer constituting the printed wiring board 1 will also be referred to as the "upper surface", and the surface facing the −Z direction will also be referred to as the "lower surface".

The core layer R1 includes a flat first insulating layer 21 and a core conductor layer C0 (inner layer circuit). The material of the first insulating layer 21 is not particularly limited. Examples include organic resins such as epoxy resins, bismaleimide-triazine resins, polyimide resins, and polyphenylene ether (PPE) resins. Two or more of these organic resins may be used in combination. When using an organic resin as the first insulating layer 21, it is preferable to mix a reinforcing material with the organic resin. Examples of the reinforcing material include glass fiber, glass nonwoven fabric, aramid nonwoven fabric, aramid fiber, and polyester fiber. Two or more of these reinforcing materials may be used in combination. The first insulating layer 21 is preferably formed from an organic resin containing a glass material such as glass fiber. Furthermore, the first insulating layer 21 may contain an inorganic filler such as silica, barium sulfate, talc, clay, glass, calcium carbonate, titanium oxide, or the like.

A portion of the core conductor layer C0 forms a predetermined wiring pattern on the upper and lower surfaces of the first insulating layer 21. Further, a part of the core conductor layer C0 is provided on the inner wall surface of a through hole penetrating the first insulating layer 21 to form a through hole. The wiring patterns on the upper and lower surfaces of the core conductor layer C0 are electrically connected through the through holes. The center axis of the through hole is filled with an insulator 23. The material of the core conductor layer C0 is, for example, copper, although it is not particularly limited.

The buildup layer R2 is laminated on the upper surface and the lower surface of the core layer R1, respectively.
The buildup layer R2 includes a flat second insulating layer 22, a copper foil C1 (metal foil), a first plating layer C2, and a second plating layer C3. The insulating layer 200 is constituted by the first insulating layer 21 of the core layer R1 and the second insulating layer 22 of the buildup layer R2. Further, the conductor portion 100 is constituted by the core conductor layer C0 of the core layer R1, the copper foil C1, the first plating layer C2, and the second plating layer C3 of the buildup layer R2.

The material of the second insulating layer 22 is not particularly limited. For example, epoxy resin, bismaleimide-triazine resin, polyimide resin, polyphenylene ether (PPE) resin, phenol resin, polytetrafluoroethylene (PTFE) resin, silicon resin, polybutadiene resin, polyester resin, melamine resin, urea resin, polyphenylene sulfide. (PPS) resin, polyphenylene oxide (PPO) resin, etc. Two or more types of these resins may be mixed. The second insulating layer 22 may contain the above-mentioned inorganic filler or an organic filler made of phenol resin or methacrylic resin.

The copper foil C1 is formed on a part of the surface of the second insulating layer 22. The copper foil C1 is obtained by patterning a copper foil layer that has been previously formed on the entire surface of the second insulating layer 22.

The first plating layer C2 is formed along the inner wall surface of the first opening 70A (see FIG. 2(b)) and the second opening 70B (see FIG. 3(b)) provided in the second insulating layer 22. It is formed by Among these, the first opening 70A has a depth smaller than the thickness of the insulating layer 200. In this specification, "depth" is the length of the insulating layer 200 in the thickness direction (Z direction). Further, the second opening 70B penetrates the insulating layer 200 from the first surface S1 to the second surface S2. Below, when referring to any one of the first opening 70A and the second opening 70B, it will be referred to as "opening 70".
The second plating layer C3 is formed in a range covering the surface of the copper foil C1 and the surface of the first plating layer C2.

The first connection conductor 40 is constituted by a portion of the first plating layer C2 and the second plating layer C3 that is formed within the range of the first opening 70A when viewed from the Z direction. The first connection conductor 40 has a via 41 that electrically connects the core conductor layer C0 and the conductor layer 60.
The second connection conductor 50 is constituted by a portion of the first plating layer C2 and the second plating layer C3 that is formed within the range of the second opening 70B when viewed from the Z direction. The second connection conductor 50 has a through hole 51 that electrically connects the conductor layer 60 on the first surface S1 and the conductor layer 60 on the second surface S2.
A conductor layer 60 is configured by the portion of the second plating layer C3 that overlaps the copper foil C1 and the copper foil C1. In other words, the conductor layer 60 is constituted by a portion of the second plating layer C3 that does not belong to either the first connection conductor 40 or the second connection conductor 50, and the copper foil C1.
Hereinafter, the structures of the first connecting conductor 40 and the second connecting conductor 50 will be explained in detail.

FIG. 2 is an enlarged view showing the vicinity of the first connection conductor 40 in FIG. 1. As shown in FIG. Of these, FIG. 2(a) is a diagram for explaining the configuration of the first connecting conductor 40, and FIG. 2(b) is a diagram for explaining the configuration of the first opening 70A. It is a diagram in which parts are omitted.
The first connection conductor 40 has a via 41, a land 42, and a surface layer 43. The via 41 electrically connects the core conductor layer C0 and the conductor layer 60 via the land 42. The surface layer 43 covers the top surface of the via 41.

As shown in FIG. 2(b), the first opening 70A in which the first connection conductor 40 is provided is formed in a direction perpendicular to the first surface S1 of the insulating layer 200 (-Z direction). has been done. The first opening 70A is a stepped portion 72 in which the diameter of the second opening A2 on the second surface S2 side (-Z direction side) of the insulating layer 200 is smaller than the diameter of the first opening A1 on the first surface S1. It is a shape that has . That is, the first opening 70A includes a shelf-shaped step 72 that is recessed from the first opening A1 on the first surface S1 toward the second surface S2, and a shelf-shaped step 72 that is recessed from the first opening A1 on the first surface S1 to the second opening A2 on the bottom surface of the step 72. It consists of a main opening 71A recessed toward the second surface S2 side. The main opening 71A reaches as far as the core conductor layer C0. The shape of the first opening A1 and the second opening A2 when viewed from the +Z direction is, for example, a circle, but is not limited to this. In any cross section passing through the first opening A1 and the second opening A2 and perpendicular to the first surface S1, if the second opening A2 is within the range of the first opening A1 in the direction parallel to the XY plane, the first opening A1 The second opening A2 can have any shape.

As shown in FIG. 2A, the first connection conductor 40 is provided so as to fill the main opening 71A and the step 72 of the first opening 70A.
Specifically, the portion of the first connection conductor 40 formed by the first plating layer C2 fills the step portion 72 and a portion of the main opening 71A. A via 41 is formed by a portion of the first plating layer C2 that is in contact with the inner wall surface of the main opening 71A. The via 41 has a recess 41a that opens at the center of the first opening 70A when viewed from a direction perpendicular to the first surface S1. This recessed portion 41a is filled with a surface layer 43 of the first connection conductor 40 that is formed of the second plating layer C3.

A land 42 is formed by a portion of the first connection conductor 40 that fills the stepped portion 72 . The land 42 consists of a first plating layer C2 and a second plating layer C3. Via 41, land 42, and surface layer 43 are integrally connected.

A portion of the conductor layer 60 formed by the second plating layer C3 is formed integrally with the surface layer 43 of the first connection conductor 40. Therefore, the conductor layer 60 is electrically connected to the first connection conductor 40. Furthermore, since the bottom of the via 41 of the first connection conductor 40 is electrically connected to the core conductor layer C0, the first connection conductor 40 electrically connects the core conductor layer C0 and the conductor layer 60. Connected.

The first connection conductor 40 protrudes from the first surface S1 in the +Z direction. Further, the surface of the first connection conductor 40 on the first surface S1 side is flush with the surface of the conductor layer 60. Here, the surface on the first surface S1 side is a surface facing in the direction (+Z direction) on the first surface S1 side with respect to the second surface S2. Moreover, two surfaces being flush means that the two surfaces are in the same virtual plane.

The distance d between the first opening A1 and the second opening A2 in the direction parallel to the first surface S1 (the X direction in FIGS. 1 and 2) is, for example, 0.2 mm or less. Further, the distance d is, for example, 0.03 mm or more.

The height h of the stepped portion 72 in the direction perpendicular to the first surface S1 is 20 μm or less. Further, the height h is, for example, 10 μm or more.

Note that, as shown in FIG. 1, a first connection conductor 40 is also provided on the second surface side of the printed wiring board 1. The structure of the first connecting conductor 40 on the second surface side is similar to the structure of the first connecting conductor 40 on the first surface side. That is, in the above description of the first connecting conductor 40 on the first surface S1 side, "first surface S1" is read as "second surface S2" and "second surface S2" is read as "first surface S1". By reading this again, the structure of the first connection conductor 40 on the second surface side will be explained.

FIG. 3 is an enlarged view showing the vicinity of the second connection conductor 50 in FIG. Of these, FIG. 3(a) is a diagram for explaining the configuration of the second connection conductor 50, and FIG. 3(b) is a diagram for explaining the configuration of the second connection conductor 50. It is a diagram in which parts are omitted.
The second connection conductor 50 has a through hole 51 and a land 52.

As shown in FIG. 3(b), the second opening 70B in which the second connection conductor 50 is provided is formed in a direction perpendicular to the first surface S1 of the insulating layer 200 (-Z direction). has been done. The second opening 70B is a stepped portion 72 in which the diameter of the second opening A2 on the second surface S2 side (-Z direction side) of the insulating layer 200 is smaller than the diameter of the first opening A1 on the first surface S1. It is a shape that has . That is, the second opening 70B includes a shelf-shaped step 72 recessed from the first opening A1 on the first surface S1 toward the second surface S2, and a second opening A2 on the bottom surface of the step 72. It consists of a main opening 71B recessed toward the second surface S2 side. The main opening 71B is a through hole that reaches the second surface S2. A step portion 72 is also formed at the edge of the second connection conductor 50 on the second surface S2 side.
The shapes of the first opening A1 and the second opening A2 viewed from the +Z direction may be the same as or different from the shapes of the first opening A1 and the second opening A2 in the first opening 70A. . Further, the distance d between the first opening A1 and the second opening A2 and the height h of the step portion 72 can be within the same range as the distance d and the height h of the first connection conductor 40. For example, the distance d and height h in the second connection conductor 50 can be the same as the distance d and height h in the first connection conductor 40.

As shown in FIG. 3(a), the second connection conductor 50 is provided so that it is in contact with the inner wall surface of the main opening 71B of the second opening 70B, and the central axis of the main opening 71B is hollow. ing. Further, the second connection conductor 50 is provided so as to fill the step portion 72.
Specifically, the portion of the second connection conductor 50 formed by the first plating layer C2 fills the step portion 72 and is in contact with the inner wall surface of the main opening 71B. Further, a portion of the second connection conductor 50 that is formed by the second plating layer C3 covers a portion of the second connection conductor 50 that is formed by the first plating layer C2. A through hole 51 is formed by a portion of the second connection conductor 50 formed on the inner wall surface of the main opening 71B. Further, a land 52 is formed by a portion of the second connection conductor 50 that fills the step portion 72. The through hole 51 and the land 52 are made up of a first plating layer C2 and a second plating layer C3. The through hole 51 and the land 52 are integrally connected.

The second connection conductor 50 protrudes from the first surface S1 in the +Z direction. Further, the surface of the second connection conductor 50 on the first surface S1 side is flush with the surface of the conductor layer 60.

[Manufacturing method of printed wiring board]
Next, a method for manufacturing printed wiring board 1 will be explained.
4 to 6 are cross-sectional views illustrating a method of manufacturing printed wiring board 1. FIG.

The method for manufacturing printed wiring board 1 according to the present embodiment includes first to seventh steps.
In the first step, as shown in FIG. 4A, a substrate is prepared in which a core conductor layer C0 as an inner layer circuit is formed inside and a copper foil C1 is formed on the entire outer surface.

In the second step, as shown in FIG. 4(b), a main opening 71A as a via pilot hole and a main opening 71B as a through hole pilot hole are formed. The main opening 71A is formed by sequentially performing laser processing on the copper foil C1 and the second insulating layer 22 while changing the conditions appropriately. The main opening 71B is formed by a drill under conditions that allow processing of the copper foil C1, the first insulating layer 21, and the second insulating layer 22.

In the third step, as shown in FIG. 5(a), a step portion 72 is formed by removing a portion of the copper foil C1 and the second insulating layer 22. As a result, a first opening 70A and a second opening 70B are formed.
In the third step, similarly to the processing of the main opening 71A in the second step, the copper foil C1 and the second insulating layer 22 are successively laser-processed by changing the conditions appropriately. However, the second insulating layer 22 is subjected to laser processing under conditions weaker than those in the second step so that only the surface layer corresponding to the height h (approximately 10 to 20 μm) of the step portion 72 is removed.
Note that instead of the above, the step portion 72 may be formed by processing the copper foil C1 and the second insulating layer 22 with a drill.
Further, the copper foil C1 may be removed by subtractive etching. However, even in this case, the second insulating layer 22 is removed by laser processing or drilling.
After the step portion 72 is formed and the surface of the second insulating layer 22 is exposed, a resin roughening treatment such as permanganic acid aqueous solution or plasma treatment is performed to clean the removal residue.

In the fourth step, as shown in FIG. 5(b), a plating resist 80 (dry film) is formed on the copper foil C1. The inner wall surfaces of the first opening 70A and the second opening 70B are not masked.

In the fifth step, as shown in FIG. 6(a), using the plating resist 80 as a mask, the exposed portions of the second insulating layer 22 that are not covered with the plating resist 80, that is, the first opening 70A and the second Electrolytic pattern plating is applied to the inner wall surface of the opening 70B to form a first plating layer C2. Here, electrolytic pattern plating is performed so that the surface of the first plating layer C2 is flush with the surface of the copper foil C1. As a result, the step portion 72 is filled with the first plating layer C2, and the first plating layer C2 is formed on the inner wall surfaces of the main openings 71A and 71B.
After completion of electrolytic pattern plating, the plating resist 80 is peeled off.

In the sixth step, as shown in FIG. 6(b), electrolytic panel plating is applied to the entire surface of the substrate to form a second plating layer C3. Here, filled plating is performed so that the recesses 41a of the vias 41 are filled.

In the seventh step, as shown in FIG. 1, etching is performed using a subtractive method to partially remove the copper foil C1 and the second plating layer C3 on the first surface S1 and the second surface S2. Form a circuit pattern. As a result, necessary circuits, component mounting pads, etc. are formed.
Note that the sixth step and the seventh step may also be performed by MSAP (Modified Semi-Additive Process) using the copper foil C1 as a seed layer.

Of the above, the second and third steps correspond to the "opening formation step," the fifth and sixth steps correspond to the "connection conductor formation step," and the sixth and seventh steps correspond to the "conductor layer formation step." This corresponds to the “formation process”.

[Modification 1]
Next, a first modification of the above embodiment will be described.
FIG. 7 is a sectional view showing a first modification of the printed wiring board 1 of the above embodiment. In Modification 1, the first plating layer C2 fills the entire first opening 70A, and the via 41 does not have the recess 41a. Further, the entire surface of the first plating layer C2 including the portion filling the first opening 70A is flush with the surface of the copper foil C1, and the flat first plating layer C2 and the copper foil C1 are flush with each other. The second plating layer C3 is stacked one on top of the other. Even with such a configuration, the same effects as in the above embodiment can be obtained.
The configuration of Modification 1 can be realized, for example, by using filled plating in the electrolytic pattern plating that forms the first plating layer C2.

[Modification 2]
Next, a second modification of the above embodiment will be described.
FIG. 8 is a sectional view showing a second modification of the printed wiring board 1 of the above embodiment. In modification 2, the first connection conductor 40 and the second connection conductor 50 are made of the first plating layer C2, and the recess 41a of the via 41 is not filled with the second plating layer C3 (surface layer 43). Even with such a configuration, the same effects as those of the above embodiment can be obtained.
The configuration of Modification 2 can be realized, for example, by forming the conductor layer 60 by MSAP using the copper foil C1 as a seed layer after forming the first plating layer C2. Note that in FIG. 8, the heights of the surfaces of the lands 42 and 52 and the height of the surface of the conductor layer 60 are different, but by adjusting the amount of formation of the first plating layer C2 and the amount of pattern formation by MSAP, It is more preferable that the surfaces of the lands 42 and 52 and the surface of the conductor layer 60 are flush with each other.

〔effect〕
As described above, the printed wiring board 1 of this embodiment includes the insulating layer 200 and the conductor part 100, and the insulating layer 200 has an opening formed in a direction perpendicular to the first surface S1 of the insulating layer 200. The conductor portion 100 has a first connection conductor 40 and a second connection conductor 50 that are provided to fill at least a portion of the opening 70 . The shape has a stepped portion 72 in which the diameter of the second opening A2 on the second surface S2 side of the insulating layer 200 is smaller than the diameter of the first opening A1 on the surface S1, and the first connecting conductor 40 and the second The connection conductor 50 is provided so as to fill the step portion 72.

In a printed wiring board with a conventional configuration that does not have the stepped portion 72, the connection portion between the conductor of the via and through hole and the conductor (conductor layer as an outer layer circuit or land) formed on the first surface of the insulating layer is Disconnection is likely to occur due to peeling (corner portions) or insufficient thickness of the connection portion. More specifically, the heat generated when components are mounted on the printed wiring board concentrates the load around the vias and through holes, especially at the connection portions with outer layer circuits, etc., and the components are likely to peel off. In addition, the connection portion is easily polished during surface preparation before and after circuit formation, which may reduce the thickness of the conductor, and even when no peeling occurs, the connection portion is likely to be disconnected. As described above, in the printed wiring board having the above-mentioned conventional configuration, it is not easy to ensure reliability of circuit connections via vias and through holes.

In contrast, in the printed wiring board 1 of the present embodiment, the second insulating layer 22 is provided with a stepped portion 72, and the first connecting conductor 40 and the second connecting conductor 50 are formed so as to fill this stepped portion 72. Therefore, the connection part P1 (see FIG. 1), which is the corner part where the via 41 is connected to the land 42 and the conductor layer 60, and the through hole 51 are connected to the land 52 and the conductor layer 60. A sufficient thickness of the conductor can be ensured at the corner portion of the connection portion P2 (see FIG. 1). Thereby, it is possible to suppress disconnection at the connecting portions P1 and P2, and even if the load is concentrated due to heat during component mounting, it is possible to prevent peeling from occurring. Therefore, higher connection reliability can be ensured.

Further, the conductor portion 100 has a first via 41 provided in the first opening 70A whose depth is smaller than the thickness of the insulating layer 200, and a land 42 connected to the via 41 and filling the step portion 72. The connecting conductor 40 and the through hole 51 provided in the second opening 70B that penetrates the insulating layer 200 from the first surface S1 to the second surface S2, and the through hole 51 that is connected to the through hole 51 and fills the stepped portion 72. The second connecting conductor 50 has at least one land 52 and a second connecting conductor 50 . According to this, in the printed wiring board 1 having at least one of the vias 41 and the through holes 51, high connection reliability can be ensured around the vias 41 and the through holes 51.

Further, the conductor section 100 includes a first connection conductor 40 and a second connection conductor 50. According to this, high connection reliability around both the via 41 and the through hole 51 can be ensured.

Further, the conductor portion 100 has a first connection conductor 40, and the via 41 has a recess 41a opening at the center of the first opening 70A when viewed from the direction perpendicular to the first surface S1. The first connection conductor 40 has a surface layer 43 that fills the recess 41a. According to this, the surface of the first connection conductor 40 can be made flat while protecting the via 41 with the surface layer 43.

Further, the conductor portion 100 has a second connection conductor 50, and the through hole 51 is in contact with the inner wall surface of the second opening 70B, and the central axis of the second opening 70B is hollow. It is provided. According to this, high connection reliability can be ensured in the through hole 51 through which the lead of the electrical component can pass.

Moreover, the first connection conductor 40 and the second connection conductor 50 protrude from the first surface S1. According to this, electrical connection can be made more easily and reliably when mounting electrical components.

Further, the conductor section 100 has a conductor layer 60 formed on the first surface S1 and electrically connected to the first connection conductor 40 and the second connection conductor 50, The surface of the connecting conductor 50 on the first surface S1 side is flush with the surface of the conductor layer 60. According to this, electrical connection can be made more easily and reliably when mounting electrical components.

Further, the distance d between the first opening A1 and the second opening A2 in the direction parallel to the first surface S1 is 0.2 mm or less. According to this, the step portion 72 can be made compact within the range where the above effects can be obtained.

Further, the height h of the stepped portion 72 in the direction perpendicular to the first surface S1 is 20 μm or less. According to this, the step portion 72 can be made compact within the range where the above effects can be obtained.

Further, the method for manufacturing the printed wiring board 1 according to the present embodiment includes an opening forming step of forming the opening 70 in a direction perpendicular to the first surface S1 of the insulating layer 200, and at least a portion of the opening 70. In the opening forming step, the diameter of the first opening A1 on the first surface S1 is An opening 70 having a step 72 in which the diameter of the second opening A2 on the second surface S2 side of the layer 200 becomes smaller is formed, and in the connection conductor forming step, a first connection conductor is formed so as to fill the step 72. 40 and a second connection conductor 50 are formed. According to such a method, printed wiring board 1 having higher connection reliability as described above can be manufactured.

Further, the opening forming step includes a step of removing the copper foil C1 previously formed on the first surface S1 by a subtractive method, and a step of removing a part of the insulating layer 200 using a laser or a drill. The method includes a step of forming a step portion 72. According to this, the step portion 72 can be formed by a simple method.

Further, in the connection conductor forming step, electrolytic pattern plating is performed so as to at least fill the step portion 72. According to this, the stepped portion 72 can be filled with a simple method.

Further, in the connection conductor forming step, after electrolytic pattern plating, electrolytic panel plating is applied to the recesses 41a formed by the electrolytic pattern plating, and the recesses 41a are filled with a conductor. According to this, the surface of the first connection conductor 40 can be flattened while filling the recess 41a with a simple method.

The method for manufacturing printed wiring board 1 also includes a conductor layer forming step of forming conductor layer 60 on first surface S1 so as to be electrically connected to first connection conductor 40 and second connection conductor 50. In the conductor layer forming step, the pattern of the conductor layer 60 is formed by subjecting the conductor formed by electrolytic panel plating to a subtractive method. According to this, a desired pattern of the conductor layer 60 can be formed while ensuring connection reliability.

The method for manufacturing printed wiring board 1 also includes a conductor layer forming step of forming conductor layer 60 on first surface S1 so as to be electrically connected to first connection conductor 40 and second connection conductor 50. In the conductor layer forming step, a pattern of the conductor layer 60 is formed by the MSAP method. According to this, a desired pattern of the conductor layer 60 can be formed while ensuring connection reliability.

Note that the above embodiment is an example, and various changes are possible.
For example, in the above embodiment, the printed wiring board 1 has been described using an example including both the first connection conductor 40 including the via 41 and the second connection conductor 50 including the through hole 51. However, the printed wiring board 1 may include only one of the first connection conductor 40 and the second connection conductor 50.

Further, the buildup layer R2 may be omitted. That is, the printed wiring board 1 may consist only of the core layer R1.
Moreover, the printed wiring board 1 may have the conductor layer 60 only on one side.

Further, the core layer R1 may include a plurality of first insulating layers 21. Further, the buildup layer R2 may include a plurality of second insulating layers 22. Further, the buildup layer R2 may be provided only on one side of the core layer R1.

Further, in the above embodiment, the lands 42 and 52 are provided within the range of the step portion 72 (that is, within the range of the first opening A1), but the present invention is not limited to this. 52 may extend to the outside of the first opening A1 of the first opening 70A or the second opening 70B.

In addition, specific details such as the configuration, structure, positional relationship, and shape shown in the above embodiments can be changed as appropriate without departing from the spirit of the present disclosure. Furthermore, the configurations, structures, positional relationships, and shapes shown in the above embodiments can be combined as appropriate without departing from the spirit of the present disclosure.

1 Printed wiring board 21 First insulating layer 22 Second insulating layer 23 Insulator 40 First connection conductor 41 Via 41a Recess 42 Land 43 Surface layer 50 Second connection conductor 51 Through hole 52 Land 60 Conductor layer 70 Opening 70A First opening 70B Second opening 71A, 71B Main opening 72 Step 80 Resist 100 Conductor 200 Insulating layer C0 Core conductor layer C1 Copper foil C2 First plating layer C3 Second plating layer P1, P2 Connection section R1 Core layer R2 Buildup layer S1 First surface S2 Second surface

Claims (14)

A printed wiring board comprising an insulating layer and a conductor part,
The insulating layer has an opening formed in a direction perpendicular to the first surface of the insulating layer,
The conductor portion includes a connection conductor provided to fill at least a portion of the opening , and a conductor layer located on the first surface ,
The opening has a step portion in which the diameter of the second opening on the second surface side of the insulating layer is smaller than the diameter of the first opening on the first surface,
The connecting conductor is provided so as to fill the stepped portion and is connected to the conductor layer of the printed wiring board. The conductor portion is
a first connecting conductor having a via provided in the first opening having a depth smaller than the thickness of the insulating layer; and a land connected to the via and filling the step;
a second through hole provided in the second opening that penetrates the insulating layer from the first surface to the second surface; and a land connected to the through hole and filling the step part. connecting conductor,
The printed wiring board according to claim 1, comprising at least one of the above. The printed wiring board according to claim 2, wherein the conductor portion includes the first connection conductor and the second connection conductor. The conductor portion has the first connection conductor,
The via has a recess that opens at the center of the first opening when viewed from a direction perpendicular to the first surface,
The printed wiring board according to claim 2 or 3, wherein the first connection conductor has a surface layer that fills the recess. The conductor portion has the second connection conductor,
According to any one of claims 2 to 4, the through hole is provided so as to be in contact with an inner wall surface of the second opening and a central axis of the second opening is hollow. printed wiring board. The printed wiring board according to any one of claims 1 to 5, wherein the connection conductor protrudes from the first surface. 7. The printed wiring board according to claim 1, wherein a surface of the connecting conductor on the first surface side is flush with a surface of the conductor layer. The printed wiring board according to any one of claims 1 to 7, wherein a distance between the first opening and the second opening in a direction parallel to the first surface is 0.2 mm or less. The printed wiring board according to any one of claims 1 to 8, wherein the height of the stepped portion in a direction perpendicular to the first surface is 20 μm or less. an opening forming step of forming an opening in a direction perpendicular to the first surface of the insulating layer;
a connecting conductor forming step of forming a connecting conductor so as to fill at least a portion of the opening,
In the opening forming step, the opening has a step shape in which the diameter of the second opening on the second surface side of the insulating layer is smaller than the diameter of the first opening on the first surface,
In the connection conductor forming step, the connection conductor is formed so as to fill the stepped portion,
The opening forming step includes:
removing the metal foil previously formed on the first surface by a subtractive method;
forming the stepped portion by partially removing a portion of the insulating layer using a laser or a drill;
A method of manufacturing a printed wiring board , including : 11. The method for manufacturing a printed wiring board according to claim 10 , wherein in the connection conductor forming step, electrolytic pattern plating is performed so as to at least fill the step portion. an opening forming step of forming an opening in a direction perpendicular to the first surface of the insulating layer;
a connecting conductor forming step of forming a connecting conductor so as to fill at least a portion of the opening,
In the opening forming step, the opening has a step shape in which the diameter of the second opening on the second surface side of the insulating layer is smaller than the diameter of the first opening on the first surface,
In the connection conductor forming step, electrolytic pattern plating is applied to at least fill the stepped portion, and after the electrolytic pattern plating, electrolytic panel plating is applied to the recesses formed by the electrolytic pattern plating, and the recesses are filled with a conductor. A method for manufacturing a printed wiring board , wherein the connecting conductor is formed so as to fill the stepped portion . an opening forming step of forming an opening in a direction perpendicular to the first surface of the insulating layer;
a connecting conductor forming step of forming a connecting conductor so as to fill at least a portion of the opening;
a conductor layer forming step of forming a conductor layer on the first surface so as to be electrically connected to the connection conductor ;
including;
In the opening forming step, the opening has a step shape in which the diameter of the second opening on the second surface side of the insulating layer is smaller than the diameter of the first opening on the first surface,
In the connection conductor forming step, the connection conductor is formed so as to fill the stepped portion,
In the method for manufacturing a printed wiring board, in the conductor layer forming step, a subtractive method is applied to a conductor formed by electrolytic panel plating to form a pattern of the conductor layer. an opening forming step of forming an opening in a direction perpendicular to the first surface of the insulating layer;
a connecting conductor forming step of forming a connecting conductor so as to fill at least a portion of the opening;
a conductor layer forming step of forming a conductor layer on the first surface so as to be electrically connected to the connection conductor ;
including;
In the opening forming step, the opening has a step shape in which the diameter of the second opening on the second surface side of the insulating layer is smaller than the diameter of the first opening on the first surface,
In the connection conductor forming step, the connection conductor is formed so as to fill the stepped portion,
In the method for manufacturing a printed wiring board, in the conductor layer forming step, a pattern of the conductor layer is formed by an MSAP method.

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