Manufacturing method of wiring boards

Abstract

Providing high-quality wiring boards. [Solution] The method for manufacturing a wiring board according to the embodiment includes forming a laminate 1P and dividing the laminate 1P into a plurality of wiring boards. Forming the laminate 1P includes forming a first build-up portion 10 on the first surface of a base substrate 100 having a first surface and a second surface, including a plurality of first insulating layers 11. Dividing the laminate 1P includes drilling a groove GB1 in the thickness direction of the first build-up portion 10 and exposing a portion of the plurality of first insulating layers 11 on the bottom surface, and cutting the base substrate 100 along the groove GB1 from the bottom surface of the groove GB1 toward the second surface of the base substrate 100. Furthermore, after dividing the laminate 1P, the method includes removing the portion of the first insulating layer 11 that constitutes the bottom surface in each of the plurality of wiring boards to expose a portion of the first surface of the base substrate 100.

Description

Technical Field

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

Background Art

[0002] Patent Document 1 discloses a method for manufacturing a wiring board, which includes 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 into a plurality of individual wiring boards along a dicing line 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, the glass substrate and the laminate laminated on both surfaces of the glass substrate are cut together by a dicing blade. There is a possibility that defects such as crack generation in the glass substrate and peeling of the resin layer from the glass substrate may occur.

Means for Solving the Problems

[0005] The present invention provides a method for manufacturing a wiring board, comprising forming a laminate and dividing the laminate into a plurality of wiring boards. Forming the laminate involves forming a first build-up portion on the first surface of a base substrate having a first surface and a second surface opposite to the first surface, such that it includes a plurality of first insulating layers. Dividing the laminate involves drilling a groove in the thickness direction of the first build-up portion and forming a groove on the bottom surface that exposes a portion of the plurality of first insulating layers, and cutting the base substrate along the groove from the bottom surface of the groove toward the second surface of the base substrate. The method for manufacturing the wiring board further includes, after the division of the laminate, removing the portion of the first insulating layer that constitutes the bottom surface in each of the plurality of wiring boards to expose a portion of the first surface of the base substrate.

[0006] According to embodiments of the present invention, the laminate can be divided into a plurality of wiring boards with good yield. [Brief explanation of the drawing]

[0007] [Figure 1] A cross-sectional view showing an example of a wiring board manufactured by the wiring board manufacturing method of 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. [Figure 3D] A cross-sectional view showing an example of a manufacturing method for a wiring board according to an embodiment. [Figure 4] A cross-sectional view showing another example of a wiring board manufactured by the wiring board manufacturing method of an embodiment of the present invention. [Figure 5A] A cross-sectional view showing an example of a manufacturing method for a wiring board according to another embodiment. [Figure 5B] A cross-sectional view showing an example of a manufacturing method for a wiring board according to another embodiment. [Figure 5C] A cross-sectional view showing an example of a manufacturing method for a wiring board according to another embodiment. [Modes for carrying out the invention]

[0008] A method for manufacturing 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 manufactured by the manufacturing method of the embodiment. Note that wiring board 1 is merely an example of a wiring board manufactured by the manufacturing method of the embodiment. For example, the laminated structure of the manufactured wiring board, and the number of conductor layers and insulating layers contained 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 contained 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.

[0009] The wiring board 1 is composed of a base substrate 100 and build-up sections 10 and 20 made up of insulating layers and conductive layers alternately laminated on both sides of the base substrate 100. The wiring board 1 has two main surfaces perpendicular to its thickness direction: a first surface 1F and a second surface 1S opposite to the first surface 1F.

[0010] The base 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 base 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 base substrate 100, a second insulating layer 21 and a second conductor layer 22 are alternately laminated to form a second build-up section 20.

[0011] Furthermore, in describing the wiring board manufactured by the manufacturing method of the embodiment, in the description of the components of the wiring board 1, the side closer to the base board 100 is referred to as "bottom," "inside," or "lower side" or "inside," and the side further from the base board 100 is referred to as "top," "outside," or "upper side" or "outside." The surface of each component of the wiring board 1 that faces the base board 100 is also referred to as the "bottom surface," and the surface that faces away from the base board 100 is also referred to as the "top surface."

[0012] For example, a through conductor 101 is formed on the base substrate 100, penetrating the base substrate 100 in the thickness direction. In the example in Figure 1, the base substrate 100 is a core substrate with build-up sections on both sides. In the following description of the wiring board 1 in Figure 1, the base substrate 100 will also be referred to as the core substrate 100. The first insulating layer 11 constituting the first build-up section 10 has a first via conductor 13 formed thereon, penetrating the first insulating layer 11 in the thickness direction and connecting conductors facing each other across the first insulating layer 11, i.e., two first conductor layers 12, or the first conductor layer 12 and the through conductor 101. The second insulating layer 21 constituting the second build-up section 20 has a second via conductor 23 formed thereon, penetrating the second insulating layer 21 in the thickness direction and connecting conductors facing each other across the second insulating layer 21, i.e., two second conductor layers 22, or the second conductor layer 22 and the through conductor 101.

[0013] The through-conductor 101 is formed by filling a through-hole 101a (see FIG. 2A) formed in the core substrate 100 with a conductor. In the illustrated example, the end surface 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 (see FIG. 2B) 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 contacts 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 (see FIG. 2B) 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 contacts the surface of the second insulating layer 21 opposite to the core substrate 100 through which the second via conductor 23 passes.

[0014] The base substrate 100 included in the wiring substrate manufactured by the manufacturing method of the embodiment is a glass substrate. The core substrate 100 of the illustrated wiring substrate 1 is formed using a glass substrate. As the glass material used for the glass substrate constituting the core substrate 100, for example, soda lime glass, borosilicate glass, or alkali-free glass, etc. can be used. These glasses can include elements such as magnesium, calcium, manganese, aluminum, lead, iron, chromium, potassium, sulfur, antimony, boron, etc. as additives. Also, the base substrate 100 included in the wiring substrate may be a substrate containing a material other than glass, such as a silicon substrate, a ceramic substrate, or a resin substrate.

[0015] The first insulating layer 11 and the second insulating layer 21 are formed using any 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.

[0016] 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 formed of 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.

[0017] The first conductor layer 12 and the second conductor layer 22 constituting the wiring substrate 1 are each patterned so as to have a predetermined conductor pattern. The first conductor layer 12 constituting the first surface 1F of the wiring substrate 1 is formed in a pattern having a plurality of conductor pads 12fp. The second conductor layer 22 constituting the second surface 1S of the wiring substrate 1 is formed in a pattern having a plurality of conductor pads 22sp.

[0018] The first build-up section 10 constituting the wiring board 1 includes a solder resist layer 10Rf formed on its outermost surface using, for example, a photosensitive polyimide resin or epoxy resin. An opening 10Rfa is formed in the solder resist layer 10Rf, and a conductor pad 12fp is exposed through the opening 10Rfa. That is, the first 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 through the opening 10Rfa. The second build-up section 20 constituting the wiring board 1 includes a solder resist layer 20Rs formed on its outermost surface using, for example, a photosensitive polyimide resin or epoxy resin. An opening 20Rsa is formed in the solder resist layer 20Rs, and a conductor pad 22sp is exposed through the opening 20Rsa. That is, the second 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 through the opening 20Rsa.

[0019] The first surface 1F of the illustrated example wiring board 1 is configured as a component mounting surface to which external electronic components are connected, and the conductor pad 12fp can be connected to the connection pads of external electronic components when the wiring board 1 is used. The second surface 1S of the wiring board 1 may be a connection surface to which the wiring board 1 is connected when the wiring board 1 is mounted on an external board, for example, which is the motherboard of any electrical device. When the wiring board 1 is used, the conductor pad 22sp can be connected to the connection pads of the external board.

[0020] 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-mentioned 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 (see Figures 3A to 3D), in the process of dividing a laminate in which multiple wiring boards 1 are connected into individual wiring boards 1, grooves GB1 are formed in the thickness direction in the first build-up portion, and then the laminate is cut through the grooves GB1. In the process of dividing the wiring boards 1 into individual pieces, the occurrence of cracks in the glass substrate is suppressed, and wiring boards 1 can be manufactured with a good yield.

[0021] In the illustrated wiring board 1, the side surface CS1 of the first build-up portion 10 extending in the thickness direction of the wiring board 1 is recessed inward relative to the core substrate 100 and the side surfaces CS2 of the second build-up portion 20. This makes it difficult for external forces to be applied to the first build-up portion 10 in the wiring board 1 after it has been separated into individual pieces. It may also make it less likely for the first build-up portion 10 to peel off from the core substrate 100 in the wiring board 1. As a result of this configuration, a part of the first surface 100f of the core substrate 100 is exposed near the side surface of the wiring board 1. The side surface CS1 of the first build-up portion 10 may include the groove side surface GS1 of the groove GB1 (see Figure 3A). The side surface CS1 is composed of the side surfaces of each individual first insulating layer 11, and the side surfaces of each first insulating layer are formed to be substantially flush with each other. The side surfaces CS2 of the core substrate 100 and the second build-up portion 20 are the cut surfaces that are exposed when a laminate in which a plurality of wiring boards 1 are connected is cut and separated into individual wiring boards 1. The side surface CS1 of the first build-up portion 10 and the cut surface, i.e., side surface CS2, of the core substrate 100 and the second build-up portion 20 do not overlap in a plan view. Although not shown in the figures, the side surface of the second build-up portion 20 may be recessed in the direction toward the interior of the wiring substrate 1 relative to the side surface CS1 of the first build-up portion 10. In this case, a groove similar to the groove GB1 formed in the first build-up portion 10 is formed in the second build-up portion 20 so as to overlap in a plan view with the groove GB1 formed in the first build-up portion 10, and then the laminate is cut. After that, on the side surface of the second build-up portion 20, similar to the side surface CS1 of the first build-up portion 10, a part of the second surface 100S of the core substrate 100 is exposed near the side surface of the second build-up portion 20. This suppresses peeling of the second build-up portion 20 and further improves the yield of the wiring substrate 1 in the individual pieceization process.

[0022] Next, with reference to Figures 2A to 2D and Figures 3A to 3D, 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 5C, 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.

[0023] The manufacturing method of the wiring board of this embodiment includes forming a laminate including a base substrate and first and second build-up portions formed on both sides of the base 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 are connected. First, Figures 2A to 2D will be shown to explain the formation of the laminate.

[0024] As shown in Figure 2A, a core substrate 100 is formed as a base substrate 100. 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.

[0025] 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.

[0026] 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.

[0027] 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.

[0028] 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 of the core substrate 100, i.e., the first surface 100f and the second surface 100s. 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.

[0029] Next, as shown in Figure 2C, on the upper side of the first surface 100f of the core substrate 100, the same process as described above for forming the first insulating layer 11 and the integral formation of the first via conductor 13 and the first conductor layer 12 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 described above for forming the second insulating layer 21 and the integral formation of the second via conductor 23 and the second conductor layer 22 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.

[0030] 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, with openings 10Rfa that expose the conductor pads 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, with openings 20Rsa that expose the conductor pads 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 a first surface 1F and a second surface 1S opposite to the first surface 1F, is completed.

[0031] Next, with reference to Figures 3A to 3D, 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 groove in the thickness direction of the first build-up portion and cutting the core substrate and the second build-up portion along the groove from the bottom surface of the groove toward the second build-up portion. The manufacturing method of the wiring board of this embodiment further includes removing the portion of the insulating layer in the first build-up portion that constitutes the bottom surface of the groove to expose a part of the first surface of the core substrate.

[0032] First, as shown in Figure 3A, grooves GB1 are formed from the first surface 1F of the wiring board 1 along the boundary BD between multiple wiring boards 1 in the laminate 1P, forming the first build-up portion 10 in the thickness direction. The grooves GB1 can be formed by cutting along the boundary BD using any dicing blade (first dicing blade, not shown), such as a diamond blade in which diamond abrasive grains are embedded in resin, which can be used for general dicing. Alternatively, the grooves GB1 may be formed by cutting using another cutting tool (cutter), such as a scriber, or by irradiating the laminate 1P with laser light, such as a carbon dioxide laser, from the outside of the first build-up portion 10. The grooves GB1 can be formed over the entire rectangular periphery of each wiring board 1 in plan view.

[0033] In the illustrated example, the groove GB1 is formed as a groove that penetrates partway through the first build-up portion 10 in the thickness direction. A portion of the first insulating layer 11 is exposed at the bottom surface of the groove GB1. That is, the bottom surface of the groove GB1 is composed of the first insulating layer 11. In the illustrated example, the first insulating layer 11 forming the bottom surface of the groove GB1 is an insulating layer 110 that is laminated to cover the first surface 100f of the core substrate 100.

[0034] The groove GB1 is formed such that a portion of the first insulating layer 11 remains as a thin layer. In this case, strict precision control in the thickness direction when forming the groove GB1 is unnecessary, and the formation of the groove GB1 becomes easier. For example, if a portion of the insulating layer 110 forms the bottom surface of the groove GB1, the thickness GB1t from the bottom surface of the groove GB1 to the core substrate 100 can be 0.3 μm or more and 40 μm or less. If the bottom surface of the groove GB1 is not flat, the thickness GB1t from the bottom surface of the groove GB1 to the core substrate 100 can be the average value of values ​​measured at at least three locations in the width direction (left-right direction in Figure 1) of the groove GB1.

[0035] Next, as shown in Figure 3B, the core substrate 100 and the second build-up portion 20 are cut along the groove GB1 from the bottom surface of the groove GB1 toward the second build-up portion 20. In this embodiment, for example, a second dicing blade DB2 cuts a portion of the first insulating layer 11 of the first build-up portion 10, the core substrate 100, and the second build-up portion 20. Individual pieces are formed when the second dicing blade DB2 reaches the surface of the solder resist layer 20Rs. The cutting of the core substrate 100 and the second build-up portion 20 can be performed by a cutting member capable of cutting the core substrate 100 and the second build-up portion 20 in the thickness direction, and the cutting member may be a dicing blade or another cutting member (cutter) such as a scriber.

[0036] In the manufacturing method of the wiring board of this embodiment, a groove GB1 is formed in the first build-up section 10 before the core substrate 100 is cut by the dicing blade. When the groove GB1 is formed, it is considered that it is easier to insert the second dicing blade DB2 substantially parallel to the thickness direction compared to when the first surface 1F of the laminate 1P is flat (when the groove GB1 is not formed). It is considered that the cutting of the core substrate 100 can be performed accurately and easily along the boundary BD.

[0037] In the illustrated example, as described above, the groove GB1 is formed as a groove that penetrates partway through the first build-up portion 10 in the thickness direction. A portion of the first insulating layer 11 is exposed at the bottom surface of the groove GB1. The second dicing blade DB2, which enters the groove GB1, first contacts the first insulating layer 11, which remains as a thin layer. It is thought that a mechanical shock is applied to the first insulating layer 11 by this contact, but the first insulating layer 11, which is mainly made of resin, easily absorbs the shock, and therefore it is thought that defects such as cracks are unlikely to occur. Subsequently, when the second dicing blade DB2 contacts the core substrate 100, the blade contacts the core substrate 100 continuously from the first insulating layer 11, so it is thought that a large shock is unlikely to be applied to the core substrate 100. Therefore, it is thought that localized stress concentration due to contact with the blade is unlikely to occur in the core substrate 100. In other words, the remaining portion of the first insulating layer 11 can act as a stress relaxation region that may occur when the core substrate 100 is cut. On the other hand, the remaining portion of the first insulating layer 11 is thin and relatively flexible, so peeling of the first insulating layer 11 from the core substrate 100 is unlikely to occur when cutting with the second dicing blade DB2.

[0038] In the method for manufacturing a wiring board of this embodiment, a different dicing blade is used as the second dicing blade DB2 used for cutting a portion of the first insulating layer 11 of the first build-up section 10, the core substrate 100, and the second build-up section 20, compared to the first dicing blade used when the groove GB1 is formed. As shown in Figure 3B, the opening width GBw of the groove GB1 is formed to be larger than the width DBw2 of the second dicing blade DB2 used for cutting a portion of the first insulating layer 11 of the first build-up section 10, and the core substrate 100 and the second build-up section 20. That is, the width DBw1 of the first dicing blade, which is the cutting member used to form the groove GB1 in the method of this embodiment, is larger than the width DBw2 of the second dicing blade DB2. Because the second dicing blade DB2 fits within the groove GB1, it is considered that misalignment of the second dicing blade DB2 in the width direction (left-right direction in Figure 3B) of the groove GB1 is less likely to occur. It is considered that cutting along the boundary BD can be easily performed. Furthermore, since the core substrate 100 is cut by a narrow blade, it is thought that damage to the core substrate 100 during cutting is reduced.

[0039] In the illustrated example of a wiring board manufacturing method, a dicing blade continuously cuts the insulating layer 110, which is the first insulating layer 11 forming the bottom surface of the groove GB1, the core substrate 100, and a plurality of second insulating layers 21. The laminate 1P is divided into individual pieces, and a plurality of wiring boards 1D (see Figure 3C) are cut out.

[0040] The cut-out wiring board 1D is a wiring board in the process of being manufactured. As shown in Figure 3C, the cut-out wiring board 1D includes a thin layer portion 111 that formed the bottom surface of the groove GB1 (see Figure 3B) in the insulating layer 110 on the core substrate 100. The side surface of the wiring board 1D is composed of the groove side surface GS1 of the groove GB1, the insulating layer 110 formed by cutting for individualization, the core substrate 100, and the cut surface of the second build-up portion 20.

[0041] Next, the thin layer portion 111 of the insulating layer 110 is removed by irradiation with laser light, such as carbon dioxide laser light. As shown in Figure 3D, a portion of the first surface 100f of the core substrate 100 is exposed by the removal. The manufacturing of the wiring board 1 is completed. In this embodiment, since the thin layer portion 111 is removed, problems caused by the peeled-off thin layer portion 111 adhering to unintended parts are prevented when the wiring board 1 is used.

[0042] The side surface of the wiring board 1 is composed of the side surface CS1 of the first build-up section 10, which includes the groove side surface GS1 (see Figure 3C) of the groove GB1 (see Figure 3B), and the side surface CS2 of the core substrate 100 and the second build-up section 20, which are cut surfaces formed by cutting for individualization. The side surface CS1 of the first build-up section 10 and the cut surfaces of the core substrate 100 and the second build-up section 20, i.e., the side surface CS2, do not overlap in a plan view. The side surface CS1 is composed of the side surfaces of individual first insulating layers 11 within the first build-up section 10, and the side surfaces of individual first insulating layers 11 are formed to be substantially flush with each other. That is, the removal of the thin layer portion 111 by laser may be performed such that the side surface of the insulating layer 110 formed by the removal and the groove side surface GS1 of the groove GB1 are substantially flush with each other. Along with the removal of the thin layer portion 111 by laser, the side surfaces of the first insulating layers 11 within the first build-up section 10 may be polished by laser. A side surface CS1 with better flatness may be obtained. In this case as well, the side surface CS1 of the first build-up portion 10 formed by the laser and the cross-section, i.e., side surface CS2, of the core substrate 100 and the second build-up portion 20 do not overlap in a plan view.

[0043] In the illustrated example, the side surface CS1 of the first build-up portion 10 is formed substantially perpendicular to the core substrate 100, i.e., without a taper. However, when irradiating the wiring board 1 with laser light from the first surface 1F side to remove the thin layer portion 111, the processing diameter on the laser incident side may be larger than the processing diameter on the opposite side. Therefore, the side surface CS1 of the first build-up portion 10 may be formed with a taper such that the end of the side surface CS1 on the first surface 1F side of the wiring board 1 is located in the direction of the interior of the wiring board 1 relative to the end of the side surface CS1 on the first surface 100f side of the core substrate 100. In this case as well, the side surface CS1 of the first build-up portion 10 may be a flat surface formed by the laser. That is, on the side surface CS1, the sides of the individual first insulating layers 11 within the first build-up portion 10 that are exposed on the side surface CS1 may be formed substantially flush with each other. It is believed that the occurrence of defects such as peeling of the first insulating layer 11 within the first build-up portion 10 can be suppressed. A wiring board of good quality can be provided.

[0044] In the above-described method for manufacturing the wiring board, the lamination 1P is divided without forming grooves or other structures in the second build-up section 20. When cutting the core substrate 100 and the second build-up section 20 using a dicing blade, localized stress concentration in the second build-up section 20 is less likely to occur. This is thought to suppress the occurrence of unintended cracks and other damage. Furthermore, misalignment between the cut surface of the first build-up section 10 and the cut surface of the second build-up section 20 is less likely to occur. This is thought to result in the wiring board 1 being cut to more accurate dimensions.

[0045] As described above, the wiring board 1 shown in Figure 1 is merely one example of a wiring board manufactured by the manufacturing method of the embodiment. In the wiring board 1 shown in Figure 1, a first build-up portion 10 and a second build-up portion 20 are formed on the first surface 100f and the second surface 100s of the core substrate 100, respectively, but the wiring board manufactured by the manufacturing method of the embodiment is not necessarily limited to this configuration. The wiring board manufactured by the manufacturing method of the embodiment may be, for example, a wiring board 1b shown in Figure 4, in which the second build-up portion is not formed on the second surface 100bs of the glass substrate 100b that functions as a base substrate.

[0046] The wiring board 1b can be manufactured in the same way as the wiring board 1, for example, by the process shown in Figures 5A to 5C. First, a laminate 1Pb is formed using the same process as shown in Figures 2B to 2D. That is, a first build-up portion 10b, which includes alternately stacked insulating layers 11b and conductive layers 12b, and via conductors 13b connecting the conductive layers 12b with the insulating layer 11b in between, is formed on the first surface 100bf of the glass substrate 100b. Next, using the same process as shown in Figure 3A, as shown in Figure 5A, grooves GB1b that cut through the first build-up portion 10b in the thickness direction are formed from the first surface 1Fb of the wiring board 1b, for example, by a dicing blade or laser, along the boundary BD between the multiple wiring boards 1b. The grooves GB1b are formed such that a portion of the insulating layer 110b is exposed at its bottom surface.

[0047] Next, using a process similar to that shown in Figure 3B, as shown in Figure 5B, a portion of the insulating layer 110b of the first build-up portion 10b and the glass substrate 100b are cut by the second dicing blade DB2 from the bottom surface of the groove GB1b toward the second surface 100bs of the glass substrate 100b. The second dicing blade DB2, having a width DBw narrower than the opening width GBwb of the groove GB1b, is used to cut a portion of the insulating layer 110b of the first build-up portion 10b and the glass substrate 100b. The laminate 1Pb is separated into individual pieces, and multiple wiring boards 1Db (see Figure 5C) are cut out.

[0048] Next, by using the same process as shown in Figures 3C and 3D, the thin layer portion 111b that constitutes the bottom surface of the groove GB1b (see Figure 5B) of the laminate 1Db shown in Figure 5C is removed. With the thin layer portion 111b removed, a part of the first surface 100bf of the glass substrate 100b is exposed as shown in Figure 4, and the manufacturing of the wiring board 1b is completed. The side surface CS1b (see Figure 4) of the first build-up portion 10b is preferably formed to be substantially flush. The side surface CS1b of the first build-up portion 10b is recessed in the direction toward the interior of the wiring board 1b relative to the side surface CS2b (cut surface) of the glass substrate 100b. The side surface CS1b of the first build-up portion 10b and the cut surface, i.e., side surface CS2b, of the glass substrate 100b do not overlap in a plan view.

[0049] The manufacturing method of the wiring board in the embodiment is not limited to the method described with reference to each drawing, and its conditions and sequence may be changed as appropriate. Depending on the structure of the wiring board being manufactured, some steps may be omitted or other steps may be added to the manufacturing method of the wiring board. Furthermore, the wiring board manufactured by the manufacturing method of the embodiment is not limited to having the structure shown in Figures 1 and 4. [Explanation of Symbols]

[0050] 1, 1b Wiring board 10, 10b First Build-up Section 11, 11b Insulating layer (first insulating layer) 110, 110b Insulating layer (first insulating layer) 12, 12b Conductor layer (first conductor layer) 13, 13b Via conductor (first via conductor) 20. Second Build-up Department 21. Insulating layer (second insulating layer) 22 Conductor layer (second conductor layer) 23 Via conductor (2nd via conductor) 100 base board 101 Through-conductor 100P, 100b glass substrate 12fp conductor pad 22sp Conductor Pad BA wiring board formation area BD boundary DB2 The Second Dicing Blade GB1 groove GS1 groove side CS1 Side view of the first build-up section Side view of CS2 core board and 2 build-up section

Claims

1. Forming a laminate, A method for manufacturing a wiring board, comprising dividing the laminate into a plurality of wiring boards, Forming the laminate includes forming a first build-up portion on the first surface of a base substrate having a first surface and a second surface opposite to the first surface, such that it includes a plurality of first insulating layers. Dividing the laminate includes drilling the first build-up portion in the thickness direction and forming a groove on the bottom surface that exposes a portion of the plurality of first insulating layers, and cutting the base substrate along the groove from the bottom surface of the groove toward the second surface of the base substrate, The method for manufacturing the wiring board further includes, after the division of the laminate, removing the portion of the first insulating layer that constitutes the bottom surface in each of the plurality of wiring boards to expose a part of the first surface of the base board.

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

3. A method for manufacturing a wiring board according to claim 1, wherein the groove is formed by a first dicing blade, the base board is cut by a second dicing blade, and the width of the first dicing blade is greater than the width of the second dicing blade.

4. Exposing a portion of the first surface of the base substrate includes forming the surfaces of the plurality of first insulating layers constituting the side surface of the first build-up portion 10 to be substantially flush with each other.

5. A method for manufacturing a wiring board according to claim 4, wherein the side surface of the first build-up portion includes the groove side surface of the groove portion.

6. A method for manufacturing a wiring board according to claim 3, wherein forming the laminate includes forming a second build-up portion on the second surface of the base substrate so as to include a plurality of second insulating layers, and dividing the laminate includes cutting the second build-up portion together with the base substrate using the second dicing blade.

7. A method for manufacturing a wiring board according to claim 1, wherein the thickness from the bottom surface of the groove to the first surface of the base board is 0.3 μm or more and 40 μm or less.

8. A method for manufacturing a wiring board according to claim 6, wherein the side surface of the first build-up portion does not overlap with the cross-sectional surfaces of the base board and the second build-up portion in a plan view.

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