Method for manufacturing a wiring board, and wiring board

Abstract

Providing high-quality wiring boards. [Solution] The method for manufacturing a wiring board according to the embodiment includes forming a laminate 1P including a core substrate 100 having a first surface 100f and a second surface 100s, a first build-up portion 10 and a second build-up portion 20, and dividing the laminate 1P into a plurality of wiring boards. Dividing the laminate 1P includes forming a first groove, forming a second groove GB2, and cutting the first build-up portion 10 and the core substrate 100 from the bottom surface of the first groove toward the second groove GB2, wherein forming the first groove or forming the second groove GB2 includes making the thickness between the bottom surface of the first groove and the first surface 100f greater than the thickness between the bottom surface of the second groove GB2 and the second surface 100s.

Description

Technical Field

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

Background Art

[0002] Patent Document 1 discloses a method for manufacturing a wiring board including cutting a substrate having a metal layer and a resin layer formed on both surfaces (one surface and the other surface) of a glass substrate along a dicing line into a plurality of individual wiring boards using a dicing blade.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the method for manufacturing a wiring board disclosed in Patent Document 1, it is necessary to cut the glass substrate and the metal layer and resin layer laminated on both surfaces of the glass substrate at once using a dicing blade, and it is not easy to divide the wiring board.

Means for Solving the Problems

[0005] The present invention provides a method for manufacturing a wiring board, comprising: forming a laminate including a core substrate having a first surface and a second surface opposite to the first surface; a first build-up portion laminated on the first surface; and a second build-up portion laminated on the second surface; and dividing the laminate into a plurality of wiring boards, wherein dividing the laminate includes forming a first groove drilled in the thickness direction of the first build-up portion; forming a second groove drilled in the thickness direction of the second build-up portion; and cutting the first build-up portion and the core substrate from the bottom surface of the first groove toward the second groove of the second build-up portion, wherein the first groove and the second groove are formed such that the bottom surfaces of the first groove and the bottom surfaces of the second groove face each other in the thickness direction, and forming the first groove or forming the second groove includes making the thickness of the first build-up portion between the bottom surface of the first groove and the first surface greater than the thickness of the second build-up portion between the bottom surface of the second groove and the second surface.

[0006] The wiring board of the present invention includes a glass substrate having a first surface, a second surface opposite to the first surface, and a side surface connecting the first surface and the second surface; a first build-up portion including a first insulating layer laminated on the first surface; and a second build-up portion including a second insulating layer laminated on the second surface. On the side surface of the glass substrate, the thickness of the first build-up portion on the upper side of the first surface and the thickness of the second build-up portion on the upper side of the second surface are different from each other.

[0007] According to embodiments of the present invention, the laminate can be easily divided into multiple wiring boards. [Brief explanation of the drawing]

[0008] [Figure 1] A cross-sectional view showing an example of a wiring board according to an embodiment of the present invention. [Figure 2A] A cross-sectional view showing an example of a manufacturing method for a wiring board according to an embodiment. [Figure 2B]A cross-sectional view showing an example of a manufacturing method for a wiring board according to an embodiment. [Figure 2C] A cross-sectional view showing an example of a manufacturing method for a wiring board according to an embodiment. [Figure 2D] A cross-sectional view showing an example of a manufacturing method for a wiring board according to an embodiment. [Figure 3A] A cross-sectional view showing an example of a manufacturing method for a wiring board according to an embodiment. [Figure 3B] A cross-sectional view showing an example of a manufacturing method for a wiring board according to an embodiment. [Figure 3C] A cross-sectional view showing an example of a manufacturing method for a wiring board according to an embodiment. [Modes for carrying out the invention]

[0009] A wiring board according to an embodiment of the present invention will be described with reference to the drawings. Figure 1 shows a cross-sectional view of wiring board 1, which is an example of a wiring board according to the embodiment. Note that wiring board 1 is merely an example of a wiring board according to the embodiment. For example, the laminated structure of the wiring board, and the number of conductor layers and insulating layers included in the wiring board, may differ from the laminated structure of wiring board 1 in Figure 1, and the number of conductor layers and insulating layers included in wiring board 1. Also, in the drawings referenced in the following description, certain parts may be enlarged to facilitate understanding of the disclosed embodiment, and the size and length of each component may not be depicted in the exact proportions between them.

[0010] The wiring board 1 is composed of a core substrate 100 and build-up sections 10 and 20, which are made up of insulating layers and conductive layers alternately laminated on both sides of the core substrate 100. The wiring board 1 has two main surfaces perpendicular to its thickness direction: one surface 1F and the other surface 1S opposite to the first surface 1F.

[0011] The core substrate 100 included in the wiring board 1 has a first surface 100f and a second surface 100s opposite to the first surface 100f. On the first surface 100f of the core substrate 100, a first insulating layer 11 and a first conductor layer 12 are alternately laminated to form a first build-up section 10. On the second surface 100s of the core substrate 100, a second insulating layer 21 and a second conductor layer 22 are alternately laminated to form a second build-up section 20.

[0012] Regarding the description of the wiring board, in the description of the components of wiring board 1, the side closer to the core board 100 is referred to as "bottom," "inside," or "lower side" or "inside," while the side further from the core board 100 is referred to as "top," "outside," or "upper side" or "outside." The side of each component of wiring board 1 that faces the core board 100 is also referred to as the "bottom surface," and the side that faces away from the core board 100 is also referred to as the "top surface."

[0013] The core substrate 100 has a through conductor 101 that penetrates the core substrate 100 in the thickness direction. The first insulating layer 11 constituting the first build-up section 10 has a first via conductor 13 that penetrates the first insulating layer 11 in the thickness direction and connects opposing conductors (either two first conductor layers 12 or one first conductor layer 12 and the through conductor 101) that are sandwiched between the first insulating layer 11. The second insulating layer 21 constituting the second build-up section 20 has a second via conductor 23 that penetrates the second insulating layer 21 in the thickness direction and connects opposing conductors (either two second conductor layers 22 or one second conductor layer 22 and the through conductor 101) that are sandwiched between the second insulating layer 21.

[0014] The through-conductor 101 is formed by filling a through-hole 101a formed in the core substrate 100 with a conductor. In the illustrated example, the end face of the through-conductor 101 in the extending direction is formed substantially flush with the surface of the core substrate 100, and constitutes the first surface 100f and the second surface 100s of the core substrate 100. The first via conductor 13 is formed by filling a through-hole 13a formed in the first insulating layer 11 with a conductor. The first via conductor 13 is integrally formed with the first conductor layer 12 that is in contact with the surface of the first insulating layer 11 opposite to the core substrate 100 through which the first via conductor 13 passes. The second via conductor 23 is formed by filling a through-hole 23a formed in the second insulating layer 21 with a conductor. The second via conductor 23 is integrally formed with the second conductor layer 22 that is in contact with the surface of the second insulating layer 21 opposite to the core substrate 100 through which the second via conductor 23 passes.

[0015] The core substrate included in a wiring board may be a glass substrate. The core substrate 100 of the illustrated wiring board 1 is formed using a glass substrate. Examples of glass materials that can be used for the glass substrate constituting the core substrate 100 include soda-lime glass, borosilicate glass, or alkali-free glass. These glasses may contain elements such as magnesium, calcium, manganese, aluminum, lead, iron, chromium, potassium, sulfur, antimony, and boron as additives. In addition, the core substrate included in a wiring board may be a substrate containing materials other than glass, such as a silicon substrate, ceramic substrate, or resin substrate.

[0016] The first insulating layer 11 and the second insulating layer 21 are formed using an arbitrary insulating resin. Examples of the insulating resin include thermosetting resins such as epoxy resin, bismaleimide triazine resin (BT resin), or phenolic resin, and thermoplastic resins such as fluororesin, liquid crystal polymer (LCP), ethylene fluoride (PTFE) resin, polyester (PE) resin, and modified polyimide (MPI) resin. The first insulating layer 11 and the second insulating layer 21 may contain inorganic fillers (not shown) such as silica and alumina. The first insulating layer 11 and the second insulating layer 21 may contain reinforcing materials (core materials) such as glass fibers and aramid fibers.

[0017] Examples of the conductors constituting the first conductor layer 12, the second conductor layer 22, the first via conductor 13, the second via conductor 23, and the through conductor 101 include copper and nickel, and preferably copper is used. In the example shown in FIG. 1, the first conductor layer 12, the second conductor layer 22, the first via conductor 13, the second via conductor 23, and the through conductor 101 are each shown as a single layer, but may be configured with a multilayer structure. The first conductor layer 12, the second conductor layer 22, the first via conductor 13, the second via conductor 23, and the through conductor 101 may have a multilayer structure including, for example, a metal foil layer (preferably a copper foil), a metal film layer (preferably a copper film formed by electroless plating or sputtering), and a plating film layer (preferably an electrolytic copper plating film). For example, the first conductor layer 12, the second conductor layer 22, the first via conductor 13, the second via conductor 23, and the through conductor 101 may have a two-layer structure including a metal film layer and a plating film layer.

[0018] Each conductor layer (the first conductor layer 12, the second conductor layer 22) constituting the wiring board 1 is patterned so as to have a predetermined conductor pattern. The first conductor layer 12 constituting one surface 1F of the wiring board 1 is formed in a pattern having a plurality of conductor pads 12fp. The second conductor layer 22 constituting the other surface 1S of the wiring board 1 is formed in a pattern having a plurality of conductor pads 22sp.

[0019] The first build-up portion 10 that constitutes the wiring board 1 includes, on its outermost side, a solder resist layer 10Rf formed using, for example, a photosensitive polyimide resin or an epoxy resin. An opening 10Rfa is formed in the solder resist layer 10Rf, and the conductor pad 12fp is exposed from the opening 10Rfa. That is, one surface 1F of the wiring board 1 includes the surface of the solder resist layer 10Rf and the surface of the conductor pad 12fp exposed from the opening 10Rfa. The second build-up portion 20 that constitutes the wiring board 1 includes, on its outermost side, a solder resist layer 20Rs formed using, for example, a photosensitive polyimide resin or an epoxy resin. An opening 20Rsa is formed in the solder resist layer 20Rs, and the conductor pad 22sp is exposed from the opening 20Rsa. That is, the other surface 1S of the wiring board 1 includes the surface of the solder resist layer 20Rs and the surface of the conductor pad 22sp exposed from the opening 20Rsa.

[0020] One surface 1F of the wiring board 1 in the illustrated example is configured as a component mounting surface to which an external electronic component is connected, and the conductor pad 12fp can be connected to the connection pad of an external electronic component in the use of the wiring board 1. The other surface 1S of the wiring board 1 can be a connection surface that is connected to an external board when the wiring board 1 is mounted on an external board that is, for example, the motherboard of an arbitrary electric device. In the use of the wiring board 1, the conductor pad 22sp can be connected to the connection pad of an external board.

[0021] The single wiring board 1 in the illustrated example is formed by dividing a laminate containing multiple wiring boards 1 into individual wiring boards 1, as will be described in detail later. The side surface extending in the thickness direction of the wiring board 1 is the surface that is exposed when the laminate is divided into individual wiring boards 1. In plan view, each wiring board 1 has a rectangular shape, and in the above-described laminate, multiple wiring boards 1 are connected in a grid pattern. Here, "plan view" means viewing the object from a line of sight parallel to the thickness direction of the wiring board 1. As will be described in detail later, in the process of dividing a laminate in which multiple wiring boards 1 are connected into individual wiring boards 1, the first groove GB1 formed in the thickness direction in the first build-up section 10 and the second groove GB2 formed in the thickness direction in the second build-up section 20 facilitate the cutting of the core substrate 100.

[0022] In the illustrated wiring board 1, the side surface (groove side surface) GS of the second build-up portion 20 extending in the thickness direction of the wiring board 1 is recessed in the direction towards the interior of the wiring board 1 (towards the side closer to the center of the wiring board 1 in a plan view) relative to the side surface (cut surface) CS of the core substrate 100 and the first build-up portion 10. The side surface (groove side surface) GS of the second build-up portion 20 and the side surface (cut surface) CS of the core substrate 100 and the first build-up portion 10 do not overlap, and this shape in which the side surface of the second build-up portion 20 is recessed relative to the side surfaces of the core substrate 100 and the first build-up portion 10 can be formed as a result of a process for dividing the laminate, which will be described later.

[0023] In the wiring board 1, the thickness of the first insulating layer 11 on the upper side of the first surface 100f and the thickness of the second insulating layer 21 on the upper side of the second surface 100s are different on the side surface (i.e., the cut surface CS) of the core substrate 100. Specifically, on the side surface of the glass substrate 100, the thickness of the second build-up portion 20 on the upper side of the second surface 100s is smaller than the thickness of the first build-up portion 10 on the upper side of the first surface 100f. In the illustrated example, the first build-up portion 10 comprises a plurality of first insulating layers 11, and the second build-up portion 20 comprises a plurality of second insulating layers 21. On the side surface of the glass substrate 100, the thickness of the second build-up portion 20 on the upper side of the second surface 100s is smaller than the thickness of one of the plurality of second insulating layers 21, and the thickness of the first build-up portion 10 on the upper side of the first surface 100f is larger than the thickness of one of the plurality of first insulating layers 11. Furthermore, on the side surface of the glass substrate 100, the thickness of the second build-up portion 20 on the upper side of the second surface 100s is zero, and the second surface 100s of the core substrate 100 may be exposed between the side surface of the glass substrate 100 and the side surface GS of the second build-up portion 20.

[0024] Next, with reference to Figures 2A to 2D and Figures 3A to 3C, the manufacturing method of the wiring board according to the embodiment will be explained, using the case where the wiring board 1 shown in Figure 1 is manufactured as an example. Unless otherwise specified, each component formed in the wiring board manufacturing method described below may be formed using the materials exemplified as the materials for the corresponding components in the description of the wiring board 1 in Figure 1. Furthermore, in Figures 2A to 3C, which will be referenced below, the metal film layer and plating film layer, which are components of each conductor layer, are not depicted, and each conductor layer is depicted as a single layer, similar to Figure 1.

[0025] The manufacturing method of the wiring board of this embodiment includes forming a laminate including a core substrate and first and second build-up portions formed on both sides of the core substrate, and dividing the laminate into a plurality of wiring boards. Here, "laminated body" refers to a state in which a plurality of wiring boards to be divided into individual pieces by dicing or scribing are connected. First, Figures 2A to 2D will be shown to explain the formation of the laminate.

[0026] As shown in Figure 2A, a core substrate 100 is formed. In forming the core substrate 100, first, a glass substrate 100P is prepared, which may include, for example, soda-lime glass, borosilicate glass, or alkali-free glass. Through holes 101a are formed in the glass substrate 100P. In forming the through holes 101a, for example, a modified area may be formed in the glass substrate 100P at the location where the through holes 101a are to be formed by irradiation with laser light, and the through holes 101a may be formed by removing the modified area with, for example, an etching solution containing an aqueous solution of hydrogen fluoride. As the laser light that forms the modified area, helium-neon lasers, argon ion lasers, excimer lasers, and various YAG lasers may be used.

[0027] Next, the interior of the formed through-hole 101a is completely filled with a conductor, and the conductor is formed to completely cover two surfaces of the glass substrate 100P that are perpendicular to the thickness direction. In forming the conductor, a metal film layer (not shown) is formed on the inner wall surface of the through-hole 101a and on the two surfaces of the glass substrate 100P, for example by electroless plating, and then a plating film layer (not shown) is formed on the metal film layer by electroplating using the metal film layer as a power supply layer. A through-conductor 101 having the metal film layer and the plating film layer is formed, and the two surfaces of the glass substrate 100P are covered with a two-layer structure of conductors consisting of the metal film layer and the plating film layer. Subsequently, the conductor layers covering both sides of the glass substrate 100P are removed, for example by CMP (chemical mechanical polishing). As shown in Figure 2A, a core substrate 100 having a first surface 100f and a second surface 100s is formed.

[0028] The core substrate 100 that is formed includes a plurality of wiring board forming regions BA corresponding to a plurality of connected wiring boards 1 to be manufactured.

[0029] Next, as shown in Figure 2B, a first insulating layer 11 is laminated to cover the first surface 100f of the core substrate 100, and then a first conductor layer 12 is formed on top of the first insulating layer 11. Simultaneously with the formation of the first conductor layer 12, a first via conductor 13 is formed integrally with the first conductor layer 12. The first insulating layer 11 is laminated over a plurality of wiring board formation regions BA, and the first conductor layer 12 and the first via conductor 13 are formed in the plurality of wiring board formation regions BA. A second insulating layer 21 is formed to cover the second surface 100s of the core substrate 100, and then a second conductor layer 22 is formed on top of the second insulating layer 21. Simultaneously with the formation of the second conductor layer 22, a second via conductor 23 is formed integrally with the second conductor layer 22. The second insulating layer 21 is laminated over a plurality of wiring board formation regions BA, and the second conductor layer 22 and the second via conductor 23 are formed in the plurality of wiring board formation regions BA.

[0030] The first insulating layer 11 and the second insulating layer 21 can be formed by thermocompression bonding of a film-like insulating resin (e.g., epoxy resin) onto the surface (first surface 100f and second surface 100s) of the core substrate 100. A through-hole 13a is formed in the first insulating layer 11 at the position where the first via conductor 13 is to be formed, for example by irradiation with carbon dioxide laser light. The first conductor layer 12 and the first via conductor 13 are formed on the inner surface of the through-hole 13a and the upper surface of the first insulating layer 11 by electroless plating or sputtering, and by electroplating a plating film (not shown) using a plating resist with appropriate openings and using the metal film layer as a power supply layer. A through-hole 23a is formed in the second insulating layer 21 at the position where the second via conductor 23 is to be formed, for example by irradiation with carbon dioxide laser light. The second conductor layer 22 and the second via conductor 23 are formed by forming a metal film layer (not shown) on the inner surface of the through hole 23a and the upper surface of the second insulating layer 21 by electroless plating or sputtering, and by forming a plating film (not shown) by electroplating using a plating resist having appropriate openings and using the metal film layer as a power supply layer.

[0031] Next, as shown in Figure 2C, on the upper side of the first surface 100f of the core substrate 100, the same process as the formation of the first insulating layer 11 and the integral formation of the first via conductor 13 and the first conductor layer 12 described above is repeated a desired number of times to form a desired number of first insulating layers 11 and first conductor layers 12. Also, on the upper side of the second surface 100s, the same process as the formation of the second insulating layer 21 and the integral formation of the second via conductor 23 and the second conductor layer 22 described above is repeated a desired number of times to form a desired number of second insulating layers 21 and second conductor layers 22. The outermost first conductor layer 12 is formed in a pattern including a conductor pad 12fp. The outermost second conductor layer 22 is formed in a pattern including a conductor pad 22sp.

[0032] Next, as shown in Figure 2D, a solder resist layer 10Rf is formed over multiple wiring board formation regions BA on the outermost first conductor layer 12 and first insulating layer 11 on the first surface 100f side of the core substrate 100, having an opening 10Rfa that exposes the conductor pad 12fp. The formation of the first build-up section 10 is completed. On the outermost second conductor layer 22 and second insulating layer 21 on the second surface 100s side of the core substrate 100, a solder resist layer 20Rs is formed over multiple wiring board formation regions BA, having an opening 20Rsa that exposes the conductor pad 22sp. The formation of the second build-up section 20 is completed. The formation of a laminate 1P in which multiple wiring boards 1, each having one surface 1F and the other surface 1S opposite to the one surface 1F, are connected is completed.

[0033] Next, with reference to Figures 3A to 3C, the process of dividing the formed laminate 1P into individual wiring boards 1 will be described. In the manufacturing method of the wiring board of this embodiment, dividing the laminate includes forming a first groove that penetrates the first build-up portion in the thickness direction, forming a second groove that penetrates the second build-up portion in the thickness direction, and cutting the first build-up portion and the core substrate from the bottom surface of the first groove toward the second groove of the second build-up portion. Here, the order in which the first groove is formed and the second groove is formed is not particularly limited. In this embodiment, the first groove is formed after the second groove is formed, but the second groove may be formed after the first groove. Alternatively, the first groove and the second groove may be formed simultaneously.

[0034] First, as shown in Figure 3A, a second groove GB2 is formed along the boundary BD between multiple wiring boards 1 in the laminate 1P, creating a second build-up portion 20 in the thickness direction. The second groove GB2 can be formed, for example, by irradiating laser light, such as a carbon dioxide laser, from the outside of the second build-up portion 20 toward the laminate 1P. The second groove GB2 may also be formed by cutting the second build-up portion 20 along the boundary BD using a blade, such as a diamond blade in which diamond abrasive grains are embedded in resin, which can be used for general dicing or scribing. The second groove GB2 can be formed over the entire rectangular periphery of each wiring board 1 in plan view.

[0035] In the illustrated example, the second groove GB2 is formed as a groove that penetrates partway through the second build-up portion 20 in the thickness direction, and a portion of the second insulating layer 21 is exposed at the bottom surface of the second groove GB2. That is, the second groove GB2 is formed such that a portion of the second insulating layer 21 remains as a thin layer. In this case, high precision in the thickness direction when forming the second groove GB2 is not required, and the formation of the second groove GB2 becomes easier. The thickness GB2t (see Figure 1) from the bottom surface of the second groove GB2 to the core substrate 100 is preferably smaller than the thickness 21t (see Figure 1) of one of the multiple second insulating layers 21 (for example, the second insulating layer 21 adjacent to the core substrate 100). For example, the thickness GB2t from the bottom surface of the second groove GB2 to the core substrate 100 can be 0.3 to 40 μm. The second groove GB2 penetrates the second build-up portion 20, and the second surface 100s of the core substrate 100 may be exposed on its bottom surface. Furthermore, when forming the second groove GB2 with a laser as described above, in order to mitigate the damage the laser inflicts on the glass, a metal film layer formed by electroless plating or sputtering, which constitutes the second conductive layer 22, may be provided on the boundary BD between the bottom surface of the second groove GB2 and the second surface 100s of the core substrate 100. In this case, the metal film layer may be exposed in the second groove GB2. The metal film layer formed by electroless plating or sputtering provided on the boundary BD is preferably a thin metal film of 1 μm or less and is in contact with the second surface 100s of the core substrate 100. Furthermore, the metal film layer may be covered by the bottom surface of the second groove GB2 of the second insulating layer 21. Furthermore, if the bottom surface of the second groove GB2 is not flat, the thickness GB2t from the bottom surface of the second groove GB2 to the core substrate 100 can be the average value of measurements taken at at least three locations in the width direction (left-right direction in Figure 1) of the second groove GB2.

[0036] Next, as shown in Figure 3B, a first groove GB1 is formed in the laminate 1P along the boundary BD between the multiple wiring boards 1, creating a first build-up section 10 in the thickness direction. The first groove GB1 and the second groove GB2 are formed such that the bottom surfaces of the first groove GB1 and the second groove GB2 face each other in the thickness direction. In this embodiment, the widths of the first groove GB1 and the second groove GB2 (lengths in the left-right direction in Figure 3B) are the same, but the widths of the first groove GB1 and the second groove GB2 may be different. For example, the width of the first groove GB1 may be narrower than the width of the second groove GB2, but wider than the width of the cutting member (dicing blade DB) described later. The first groove GB1 can be formed, for example, by irradiating the laminate 1P with laser light, such as a carbon dioxide laser, from the outside of the first build-up section 10. The first groove GB1 may be formed by cutting the first build-up portion 10 along the boundary BD using a blade, such as a diamond blade in which diamond abrasive grains are embedded in resin, which can be used for general dicing or scribing. The first groove GB1 may be formed over the entire rectangular periphery of each individual wiring board 1 in plan view.

[0037] In the illustrated example, the first groove GB1 is formed as a groove that penetrates partway through the first build-up portion 10 in the thickness direction, and a portion of the first insulating layer 11 is exposed at the bottom surface of the first groove GB1. In the formation of the first groove GB1 or the second groove GB2, the thickness of the first build-up portion 10 between the bottom surface of the first groove GB1 and the first surface 100f of the core substrate 100 is made greater than the thickness of the second build-up portion 20 between the bottom surface of the second groove GB2 and the second surface 100s of the core substrate 100. In this embodiment, the first build-up portion 10 and the second build-up portion 20 have the same number of layers, and the depth in the thickness direction of the first groove GB1 is shallower than the depth in the thickness direction of the second groove GB2. In other words, the first groove GB1 and the second groove GB2 are formed such that the thickness from the bottom surface of the first groove GB1 to the first surface 100f of the core substrate 100 is greater than the thickness from the bottom surface of the second groove GB2 to the second surface 100s of the core substrate 100. In this embodiment, the thickness of the first build-up portion 10 on the upper side of the first surface 100f is greater than the thickness of one of the multiple first insulating layers 11. In this embodiment, as shown in Figure 3B, the first build-up portion 10 and the second build-up portion 20 each have three insulating layers 11 and 21. The first build-up portion 10 and the second build-up portion 20 may each have four or more layers. The number of insulating layers 11 remaining between the bottom surface of the first groove GB1 and the first surface 100f of the core substrate 100 is greater than the number of insulating layers 21 remaining between the bottom surface of the second groove GB2 and the second surface 100s of the core substrate 100.

[0038] Next, as shown in Figure 3C, the first build-up portion 10 and the core substrate 100 are cut from the bottom surface of the first groove GB1 toward the second groove GB2 of the second build-up portion 20. In this embodiment, for example, a dicing blade DB cuts a portion of the first insulating layer 11 of the first build-up portion 10 and a portion of the second insulating layer 21 of the core substrate 100 and the second build-up portion 20. When the dicing blade DB reaches the bottom surface of the second groove GB2, the individual wiring boards 1 are separated into individual pieces. Note that the cutting of the first build-up portion 10 and the core substrate 100 can be performed by a cutting member capable of cutting the first build-up portion 10 and the core substrate 100 in the thickness direction, and the cutting member may be a dicing blade DB or another cutting member (cutter) such as a scriber.

[0039] In the manufacturing method of the wiring board of this embodiment, the second groove GB2 is formed in the second build-up portion 20 before the core substrate 100 and the first build-up portion 10 are cut. Therefore, when the core substrate 100 is cut by a cutting member such as a dicing blade DB, stress is concentrated near the bottom surface of the pre-formed second groove GB2. This stress concentration is thought to promote cutting near the bottom surface of the second groove GB2, making it easier to cut the core substrate 100. Therefore, it becomes possible to easily divide the laminate 1P into multiple wiring boards.

[0040] Furthermore, in the manufacturing method of the wiring board of this embodiment, a first groove GB1 is formed in the first build-up section 10 before the core substrate 100 is cut by a cutting member such as a dicing blade DB. When the first groove GB1 is formed, it is considered that it is easier to insert the cutting member such as the dicing blade DB in the thickness direction compared to when one surface 1F of the laminate 1P is flat (when the first groove GB1 is not formed). Therefore, it is considered that cutting the core substrate 100 becomes easier. Although a force is applied to the laminate 1P in the thickness direction by the cutting member such as the dicing blade DB, the first build-up section 10 of the laminate 1P can maintain a predetermined rigidity because the depth of the first groove GB1 in the thickness direction is shallower than the depth of the second groove GB2 in the thickness direction. Therefore, it is possible to suppress damage such as unintended cracks in the laminate 1P when the cutting member such as the dicing blade DB enters the first build-up section 10.

[0041] In the illustrated example, as described above, the second groove GB2 is formed as a groove that penetrates partway through the second build-up portion 20 in the thickness direction, and a portion of the second insulating layer 21 is exposed at the bottom surface of the second groove GB2. In this case, since a portion of the second insulating layer 21 remains as a thin layer, when the core substrate 100 is cut by a cutting member such as a dicing blade DB, it is thought that the second insulating layer 21 is cut due to stress concentration in the thin portion of the second insulating layer 21 after the cutting member has penetrated the core substrate 100. Therefore, it is thought that the laminate 1P can be easily divided into multiple wiring boards, and damage to the core substrate 100 is suppressed.

[0042] In the illustrated example, the width DBw of the cutting member (dicing blade DB in the embodiment) is smaller than the opening width GB2w of the second groove GB2. In this case, even if the cutting member, such as the dicing blade DB, is misaligned in the width direction of the second groove GB2 (left-right direction in Figure 3C), the cutting member is more likely to fit within the second groove GB2. Therefore, the core substrate 100 is less likely to be divided at an unintended position due to relative misalignment between the cutting member and the second groove GB2. However, the width DBw of the cutting member may be the same as the opening width GB2w of the second groove GB2, or it may be larger than the opening width GB2w of the second groove GB2.

[0043] In the illustrated example of a wiring board manufacturing method, the dicing blade DB continuously cuts through multiple first insulating layers 11, the core substrate 100, and the second insulating layer 21 that constitutes the bottom surface of the second groove GB2. When the core substrate 100 is exposed on the bottom surface of the second groove GB2, the dicing blade DB continuously cuts through multiple first insulating layers 11 and the core substrate 100. When a metal film layer is exposed on the bottom surface of the second groove GB2, the dicing blade DB continuously cuts through multiple first insulating layers 11, the core substrate 100, and the metal film layer.

[0044] As a result of cutting the core substrate 100, the first build-up section 10, and the second build-up section 20, the manufacturing of the individualized wiring board 1 is completed, as shown in Figure 1. [Explanation of symbols]

[0045] 1 Wiring board 10. First Build-up Department 20. Second Build-up Department 11. Insulating layer (first insulating layer) 21. Insulating layer (second insulating layer) 12 Conductor layer (First conductor layer) 22 Conductor layer (second conductor layer) 13 Via conductor (first via conductor) 23 Via conductor (2nd via conductor) 100 core boards 101 Through-conductor 12fp conductor pad 22sp Conductor Pad BA wiring board formation area BD boundary DB Dicing Blade GB1 First Groove GB2 Second Groove

Claims

1. To form a laminate including a core substrate having a first surface and a second surface opposite to the first surface, a first build-up portion laminated on the first surface, and a second build-up portion laminated on the second surface, Dividing the aforementioned laminate into multiple wiring boards, A method for manufacturing a wiring board, including, Dividing the laminate includes forming a first groove in the thickness direction of the first build-up portion, forming a second groove in the thickness direction of the second build-up portion, and cutting the first build-up portion and the core substrate from the bottom surface of the first groove toward the second groove of the second build-up portion. The first groove and the second groove are formed such that the bottom surface of the first groove and the bottom surface of the second groove face each other in the thickness direction. Forming the first groove or the second groove includes making the thickness of the first build-up portion between the bottom surface of the first groove and the first surface greater than the thickness of the second build-up portion between the bottom surface of the second groove and the second surface.

2. A method for manufacturing a wiring board according to claim 1, wherein the core substrate includes a glass substrate.

3. A method for manufacturing a wiring board according to claim 1, wherein forming the laminate includes forming the first build-up portion to include a plurality of first insulating layers, and cutting the first build-up portion and the core substrate includes cutting the plurality of first insulating layers and the core substrate.

4. A method for manufacturing a wiring board according to claim 1, wherein forming the second groove includes exposing the core substrate on the bottom surface of the second groove.

5. A method for manufacturing a wiring board according to claim 1, wherein forming the laminate includes forming the second build-up portion to include a plurality of second insulating layers, and forming the second groove includes exposing a portion of the plurality of second insulating layers on the bottom surface of the second groove.

6. A method for manufacturing a wiring board according to claim 5, wherein the thickness from the bottom surface of the second groove to the core substrate is 0.3 to 40 μm.

7. A method for manufacturing a wiring board according to claim 1, wherein the width of the cutting member for cutting the first build-up portion and the core board is smaller than the opening width of the first groove portion.

8. A method for manufacturing a wiring board according to claim 1, wherein the first build-up portion and the second build-up portion each have at least four or more insulating layers, and the number of insulating layers remaining between the bottom surface of the first groove portion and the first surface of the core substrate is greater than the number of insulating layers remaining between the bottom surface of the second groove portion and the second surface of the core substrate.

9. A method for manufacturing a wiring board according to claim 1, wherein forming the laminate includes forming the first build-up portion to include a plurality of first insulating layers and forming the second build-up portion to include a plurality of second insulating layers, forming the first groove portion includes exposing a portion of the plurality of first insulating layers on the bottom surface of the first groove portion, and forming the second groove portion includes exposing the core substrate on the bottom surface of the second groove portion.

10. A method for manufacturing a wiring board according to claim 1, wherein the groove side surface of the second build-up portion that defines a part of the second groove portion does not overlap with the core substrate and the cut surface of the first build-up portion.

11. A glass substrate having a first surface, a second surface opposite to the first surface, and a side surface connecting the first surface and the second surface, A first build-up portion including a first insulating layer laminated on the first surface, A second build-up portion including a second insulating layer laminated on the second surface, A wiring board including, On the side surface of the glass substrate, the thickness of the first build-up portion on the upper side of the first surface and the thickness of the second build-up portion on the upper side of the second surface are different from each other.

12. The wiring board according to claim 11, wherein, on the side surface of the glass substrate, the thickness of the second build-up portion on the upper side of the second surface is smaller than the thickness of the first build-up portion on the upper side of the first surface.

13. A wiring board according to claim 12, wherein the first build-up portion has a side surface on an inward side of the glass substrate, and the second build-up portion has a side surface on an inward side of the glass substrate.

14. The wiring board according to claim 13, wherein the thickness of the second build-up portion on the upper side of the second surface is zero on the side surface of the glass substrate, and the second surface is exposed between the side surface of the glass substrate and the side surface of the second build-up portion.

15. A wiring board according to claim 13, wherein the first build-up layer comprises a plurality of first insulating layers, and the second build-up layer comprises a plurality of second insulating layers, wherein on the side surface of the glass substrate, the thickness of the second build-up portion on the upper side of the front second surface is less than the thickness of one of the plurality of second insulating layers, and the thickness of the first build-up portion on the upper side of the first surface is greater than the thickness of one of the plurality of first insulating layers.

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