Wiring board assembly, wiring board, and method for manufacturing a wiring board

Abstract

To provide a wiring board assembly, a wiring board, and a wiring board manufacturing method that suppress damage and peeling during cutting.SOLUTION: A wiring board assembly includes a wiring structure, and a solder resist layer 130 that covers a wiring layer on the surface of the wiring structure and protects a wiring. The solder resist layer covers the surface of the wiring structure to protect the wiring, and includes a slit 132 that exposes a predetermined region of the surface corresponding to the cutting region CR of the surface of the wiring structure. The edge of the outermost insulating layer corresponding to the edge 132a of the slit 132 meanders in a wavy manner.SELECTED DRAWING: Figure 3

Description

Technical Field

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

Background Art

[0002] Conventionally, a wiring board for mounting a semiconductor chip is not manufactured as a single unit, but is manufactured as an assembly in which a plurality of wiring boards are arranged. The plurality of wiring boards manufactured as an assembly are cut into individual pieces by a cutting tool such as a dicing saw or a slicer. Each individual wiring board obtained by fragmentation becomes a wiring board for mounting a semiconductor chip.

[0003] When the assembly is fragmented, the solder resist layer covering the wiring structure of the wiring board is generally cut by a cutting tool together with the wiring structure. In the solder resist layer, there is a risk of damage such as chipping or cracking due to contact with the cutting tool. On the other hand, a linear slit wider than the cutting tool is formed in the solder resist layer corresponding to the cutting region on the surface of the wiring structure to be cut, and the wiring structure is cut in the cutting region exposed from such a linear slit to fragment the assembly. By cutting the wiring structure in the cutting region exposed from the linear slit in the solder resist layer, contact between the solder resist layer and the cutting tool can be avoided, and the occurrence of damage to the solder resist layer can be suppressed.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, when cutting a wiring structure in a cutting area exposed through a linear slit in the solder resist layer, there is a problem in that delamination may occur between the solder resist layer and the wiring structure. Specifically, in the cutting area exposed through a linear slit in the solder resist layer, the surface of the wiring structure is not covered by the solder resist layer, and the load acting on the wiring structure from the cutting tool increases in the direction away from the solder resist layer. As a result, the solder resist layer and the wiring structure may delaminate.

[0006] Furthermore, in a structure where the slit is formed wider than the cutting area to avoid contact between the solder resist layer and the cutting tool (the structure described in Patent Document 1), the load acting on the wiring structure from the cutting tool is applied to the surface of the wiring structure that is not protected by the solder resist layer. Therefore, there is a risk that damage such as chipping or cracking may occur on the surface of the wiring structure that is not protected by the solder resist layer.

[0007] The disclosed technology has been made in view of the above, and aims to provide a wiring board assembly, a wiring board, and a method for manufacturing a wiring board that can suppress damage and peeling during cutting. [Means for solving the problem]

[0008] In one embodiment, the wiring board assembly disclosed in this application comprises a wiring structure and an insulating layer. The insulating layer covers the surface of the wiring structure and includes slits that expose a predetermined area of ​​the surface of the wiring structure. The edge of the outermost insulating layer corresponding to the edge of the slit is wavy and meandering. [Effects of the Invention]

[0009] One embodiment of the wiring board assembly disclosed in this application has the effect of suppressing damage and peeling that occur when the board is cut. [Brief explanation of the drawing]

[0010] [Figure 1]Figure 1 is a schematic cross-sectional view showing the configuration of a wiring board assembly according to an embodiment. [Figure 2] Figure 2 is a plan view showing the configuration of a wiring board assembly according to an embodiment. [Figure 3] Figure 3 is a magnified view of the slit shape. [Figure 4] Figure 4 shows another example of the shape of the edge of the solder resist layer. [Figure 5] Figure 5 shows another example of the shape of the edge of the solder resist layer. [Figure 6] Figure 6 is a flowchart showing a wiring board assembly and a method for manufacturing a wiring board according to an embodiment. [Figure 7] Figure 7 shows a specific example of the core substrate formation process. [Figure 8] Figure 8 shows a specific example of the build-up process. [Figure 9] Figure 9 shows a specific example of the solder resist layer formation process. [Figure 10] Figure 10 is a diagram illustrating the formation of the slit. [Figure 11] Figure 11 shows a specific example of the terminal formation process. [Figure 12] Figure 12 is a plan view showing the configuration of a wiring board according to an embodiment. [Modes for carrying out the invention]

[0011] The embodiments of the wiring board assembly, wiring board, and method for manufacturing the wiring board disclosed in this application will be described in detail below with reference to the drawings. However, the disclosed technology is not limited by these embodiments.

[0012] FIG. 1 is a schematic cross-sectional view showing the configuration of a wiring board assembly 100 according to an embodiment. The wiring board assembly 100 is an assembly in which a plurality of wiring boards 100a are arranged. The plurality of wiring boards 100a manufactured as the wiring board assembly 100 are cut and separated into individual pieces by a cutting tool such as a dicing saw or a slicer, for example, in a cutting region CR formed in a grid pattern.

[0013] The wiring board assembly 100 has a laminated structure and includes a core board 110, a wiring structure 120, and solder resist layers 130 and 140. In the following, as shown in FIG. 1, it will be described assuming that the solder resist layer 140 is the lowermost layer and the solder resist layer 130 is the uppermost layer. However, the wiring board assembly 100 may be used, for example, upside down, or may be used in any orientation.

[0014] The core board 110 is formed by forming wiring layers 113 on both surfaces of a base material 111, which is a plate-shaped insulator, by metal plating. The wiring layers 113 on both surfaces are connected by vias 112 that penetrate the base material 111 as necessary.

[0015] The wiring structure body 120 is formed by laminating layers including an insulating insulating layer 121 and a conductive wiring layer 122. The insulating layer 121 is formed using an insulating resin such as an epoxy resin and a polyimide resin. The wiring layer 122 is formed using a metal such as copper or a copper alloy. In FIG. 1, two layers are laminated in the wiring structure body 120 above the core board 110, and two layers are laminated in the wiring structure body 120 below the core board 1, but the number of laminated layers may be one layer or three or more layers. The adjacent wiring layers 113 and 122 are connected by vias 123 that penetrate the insulating layer 121 as necessary.

[0016] The solder resist layer 130 covers the wiring layer 122 on the surface of the wiring structure 120 and is a layer for protecting the wiring. The solder resist layer 130 is a layer made of an insulating photosensitive resin such as an acrylic resin and a polyimide resin, and is one of the insulating layers. The solder resist layer 130 is an example of the outermost insulating layer.

[0017] The side of the wiring board assembly 100 on the solder resist layer 130 side is a surface on which electronic components such as semiconductor chips are mounted. At the position where the semiconductor chip is mounted, an opening 131 is formed in the solder resist layer 130. Since the solder resist layer 130 is formed using a photosensitive resin, the opening 131 can be formed by exposure and development. And a connection terminal 150 for connecting the wiring layer 122 of the wiring structure 120 and the electrode of the semiconductor chip is formed in the opening 131.

[0018] Also, the solder resist layer 130 has a slit 132 corresponding to the cutting region CR on the surface of the wiring structure 120. In the slit 132, the cutting region CR on the surface of the wiring structure 120 is exposed. Since the solder resist layer 130 is formed using a photosensitive resin, the slit 132 can be formed together with the opening 131 by exposure and development.

[0019] The solder resist layer 140, similar to the solder resist layer 130, covers the wiring layer 122 on the surface of the wiring structure 120 and is a layer for protecting the wiring. The solder resist layer 140 is a layer made of an insulating photosensitive resin such as an acrylic resin and a polyimide resin, and is one of the insulating layers. The solder resist layer 140 is an example of the outermost insulating layer.

[0020] The solder resist layer 140 side of the wiring board assembly 100 is the side that connects to external components and equipment. At the locations where external connection terminals that electrically connect to external components and equipment are formed, an opening 141 is formed in the solder resist layer 140, and the wiring layer 122 of the wiring structure 120 is exposed through the opening 141. External connection terminals, such as solder balls, are formed in the opening 141. Since the solder resist layer 140 is formed using a photosensitive resin, the opening 141 can be formed by exposure and development.

[0021] Furthermore, the solder resist layer 140 is provided with slits 142 corresponding to the cut region CR on the surface of the wiring structure 120. The cut region CR on the surface of the wiring structure 120 is exposed in the slits 142. Since the solder resist layer 140 is formed using a photosensitive resin, it is possible to form the slits 142 together with the openings 141 by exposure and development.

[0022] Figure 2 is a plan view showing the configuration of the wiring board assembly 100 according to the embodiment. In Figure 2, a top view of the wiring board assembly 100 as seen from the solder resist layer 130 side is shown. As shown in Figure 2, the solder resist layer 130 has a plurality of slits 132 formed along the grid-like cut regions CR. The plurality of slits 132 intersect with each other.

[0023] Figure 3 is a magnified view showing the shape of the slit 132. In Figure 3, the part labeled A in Figure 2 is shown in magnified view. Note that although the shape of the slit 132 in the solder resist layer 130 is described here, the slit 142 in the solder resist layer 140 has a similar shape to the slit 132.

[0024] As shown in Figure 3, the edge 132a of the solder resist layer 130, which corresponds to the edge of the slit 132, has a wavy, meandering shape. Compared to a solder resist layer with a non-meandering edge, the solder resist layer 130 with a wavy, meandering edge has a smaller contact area between the solder resist layer 130 and the periphery of the cutting region CR on the surface of the wiring structure 120, resulting in a smaller frictional force acting on the solder resist layer 130 from the cutting tool.

[0025] In other words, when the wiring structure 120 is cut by the cutting tool in the cutting region CR exposed from the slit 132, the edge 132a of the solder resist layer 130 corresponding to the edge of the slit 132 comes into contact with the cutting tool. At this time, because the edge 132a of the solder resist layer 130 is meandering in a wavy manner, the frictional force acting on the solder resist layer 130 from the cutting tool is relatively small, and the load acting on the solder resist layer 130 from the cutting tool is not very large. As a result, damage and peeling of the solder resist layer 130 can be suppressed. Furthermore, since peeling of the solder resist layer 130 can be prevented, adhesion between the surface of the wiring structure 120 and the solder resist layer 130 is maintained outside the cutting region CR. In addition, since the solder resist layer 130 protects the wiring structure 120, chipping and cracking of the surface of the wiring structure 120 can be prevented.

[0026] Furthermore, the edge 132a of the solder resist layer 130 corresponding to the edge of the slit 132 is wavy and meandering, containing waves made up of multiple interconnected arcs. Specifically, the edge 132a of the solder resist layer 130 is formed by connecting multiple semi-circular convex portions to each other. By wavy and meandering, containing waves made up of multiple interconnected arcs, the contact area between the solder resist layer 130 and the periphery of the cut region CR on the surface of the wiring structure 120 is reduced.

[0027] Furthermore, the multiple protrusions constituting the edge 132a of the solder resist layer 130 have vertices at positions that are in contact with the periphery of the cut region CR. This minimizes the contact area between the solder resist layer 130 and the periphery of the cut region CR on the surface of the wiring structure 120.

[0028] Furthermore, at least one of the multiple protruding portions 132a1 that constitute the edge 132a of the solder resist layer 130 is positioned opposite the corner formed by the multiple intersecting slits 132. This suppresses the occurrence of delamination between the solder resist layer 130 and the wiring structure 120 near the corner formed by the multiple intersecting slits 132, and as a result, the adhesion between the surface of the wiring structure 120 and the solder resist layer 130 is maintained.

[0029] Furthermore, the shape of the edge 132a of the solder resist layer 130 corresponding to the edge of the slit 132 may be any other shape as long as it is a wavy, meandering shape. Figures 4 and 5 show other examples of the shape of the edge 132a of the solder resist layer 130. For example, as shown in Figure 4, the shape of the edge 132a of the solder resist layer 130 may be a wavy, meandering shape in which the convex portion 132a1 of the solder resist layer 130 is omitted. In other words, the edge 132a of the solder resist layer 130 may have no corners facing the corners formed by the multiple intersecting slits 132. By having no corners on the edge 132a of the solder resist layer 130, peeling, chipping, and cracking of the solder resist layer 130 due to contact with a cutting tool can be suppressed.

[0030] Furthermore, as shown in Figure 5, for example, the edge 132a of the solder resist layer 130 may be wavy, including a triangular wave. Although not shown, the edge 132a of the solder resist layer 130 may meander in a wavy manner, including at least one wave selected from a wave consisting of multiple interconnected arcs, a triangular wave, a square wave, and a trapezoidal wave. Also, at least one of the multiple convex portions constituting the edge 132a of the solder resist layer 130 may be of a different size from at least one of the multiple convex portions.

[0031] Next, a method for manufacturing the wiring board assembly 100 and the wiring board 100a configured as described above will be explained with reference to Figure 6, with specific examples. Figure 6 is a flowchart showing a method for manufacturing the wiring board assembly 100 and the wiring board 100a according to the embodiment.

[0032] First, a core substrate 110, which will serve as a support member for the wiring board assembly 100, is formed (step S101). Specifically, as shown in Figure 7, for example, vias 112 penetrating the substrate 111 are formed on a base material 111, which is a plate-shaped insulator, and wiring layers 113 made of a metal such as copper are formed on both sides of the base material 111, for example, by copper foil or copper plating. Figure 7 shows a specific example of the core substrate formation process. The wiring layers 113 on both sides of the base material 111 are connected by vias 112 formed by metal plating such as copper, as needed. As the base material 111, for example, a reinforcing material such as glass woven fabric impregnated with an insulating resin such as epoxy resin can be used. As the reinforcing material, in addition to glass woven fabric, glass nonwoven fabric, aramid woven fabric, or aramid nonwoven fabric can be used. As the insulating resin, in addition to epoxy resin, polyimide resin or cyanate resin can be used.

[0033] Furthermore, multiple wiring board formation regions 100b are set on the upper and lower surfaces of the core substrate 110, spaced apart by the same width as the cutting region CR, and a wiring board 100a is formed in each wiring board formation region 100b. In other words, multiple wiring boards 100a are formed using a single core substrate 110.

[0034] Then, a wiring structure 120 is formed on the upper and lower surfaces of the core substrate 110 by a build-up method (step S102). Specifically, as shown in Figure 8, for example, an insulating layer 121 is formed on the upper and lower surfaces of the core substrate 110, and a wiring layer 122 is formed on the surface of the insulating layer 121. Figure 8 is a diagram showing a specific example of the build-up process. The insulating layer 121 is formed using an insulating resin such as epoxy resin or polyimide resin. The wiring layer 122 is formed by plating a metal such as copper.

[0035] The wiring layers 113 and 122 of the core substrate 110, or the wiring layers 122 of adjacent layers, are connected by vias 123 formed by metal plating, such as copper, as needed. Multiple insulating layers 121 and wiring layers 122 may be laminated on the upper and lower surfaces of the core substrate 110, respectively.

[0036] Once the wiring structure 120 is formed, the wiring layer 122 on the surface of the wiring structure 120 is covered with solder resist layers 130 and 140 (step S103). That is, the wiring layer 122 on the surface of the wiring structure 120 laminated on the upper surface of the core substrate 110 is covered with solder resist layer 130, and the wiring layer 122 on the surface of the wiring structure 120 laminated on the lower surface of the core substrate 110 is covered with solder resist layer 140.

[0037] Then, as shown in Figure 9, for example, an opening 131 is formed in the solder resist layer 130 on the side on which the semiconductor chip is mounted, at a position where connection terminals to the semiconductor chip are provided. The wiring layer 122 on the surface of the wiring structure 120 is exposed at the bottom of the opening 131. Figure 9 is a diagram showing a specific example of the solder resist layer formation process. In addition, a slit 132 is formed in the solder resist layer 130 at a position corresponding to the cut region CR on the surface of the wiring structure 120. The cut region CR on the surface of the wiring structure 120 is exposed at the bottom of the slit 132.

[0038] On the other hand, in the solder resist layer 140 on the side connected to external components or equipment, an opening 141 is formed at the location where the external connection terminal is provided. The wiring layer 122 on the surface of the wiring structure 120 is exposed at the bottom of the opening 141. In addition, a slit 142 is formed in the solder resist layer 140 at a location corresponding to the cut region CR on the surface of the wiring structure 120. The cut region CR on the surface of the wiring structure 120 is exposed at the bottom of the slit 142.

[0039] Since photosensitive resin is used for the solder resist layers 130 and 140, it is possible to simultaneously form the opening 131 and slit 132, or the openings 141 and 142, by exposure and development. Alternatively, the exposure and development of the solder resist layer 130 and the exposure and development of the solder resist layer 140 may be performed separately.

[0040] Figure 10 illustrates the formation of the slit 132. For example, as shown in the upper part of Figure 10, a pattern mask is formed on the surface of the solder resist layer 130 according to the shape of the slit 132 (and opening 131), and exposure is performed, causing the solder resist layer 130 in the areas where the pattern mask is not formed to harden. Specifically, the solder resist layer 130 is hardened in the areas where the slit 132 (and opening 131) is not formed. The parts of the solder resist layer 130 that are hardened by exposure become the remaining parts after development.

[0041] When the solder resist layer 130 hardens due to exposure, development is performed, and only the hardened remaining portion remains on the surface of the wiring structure 120. That is, for example, as shown in the lower part of Figure 10, the remaining portion of the solder resist layer 130 covers the surface of the wiring structure 120, and in the portion other than the remaining portion, a slit 132 is formed that exposes the cut region CR on the surface of the wiring structure 120. The edge 132a of the solder resist layer 130 corresponding to the edge of this slit 132 is wavy and meandering.

[0042] Then, connection terminals for connecting semiconductor chips are formed in the openings 131 of the solder resist layer 130 (step S104). That is, connection terminals 150 are formed in the openings 131, for example by copper plating. Through these steps, a wiring board assembly 100 including multiple wiring boards 100a is obtained, for example as shown in Figure 11. Figure 11 is a diagram showing a specific example of the terminal formation process. If necessary, semiconductor chips may be mounted on the solder resist layer 130 side, and the connection terminals 150 and the electrodes of the semiconductor chips may be joined by solder, for example.

[0043] Then, the individual wiring boards 100a are separated into individual pieces (step S105). Specifically, the wiring board assembly 100 shown in Figure 11 is cut in the cutting region CR exposed from the slit 132 using a cutting tool such as a dicer or slicer, thereby obtaining multiple wiring boards 100a. At this time, because the edge 132a of the solder resist layer 130 corresponding to the edge of the slit 132 (see Figure 3) is wavy and meandering, the frictional force acting on the solder resist layer 130 from the cutting tool is relatively small, and the load acting on the solder resist layer 130 from the cutting tool is not very large. As a result, damage and peeling of the solder resist layer 130 can be suppressed. In addition, since peeling of the solder resist layer 130 can be prevented, adhesion between the surface of the wiring structure 120 and the solder resist layer 130 is maintained outside the cutting region CR. Furthermore, since the solder resist layer 130 protects the wiring structure 120, chipping and cracking of the surface of the wiring structure 120 can be prevented.

[0044] In each wiring board 100a, for example as shown in Figure 12, the side surface of the solder resist layer 130 is formed along the peripheral edge 120a of the surface of the wiring structure 120 and is meandering in a wavy manner. Figure 12 is a plan view showing the configuration of the wiring board 100a according to the embodiment. Although not shown, in each wiring board 100a, the side surface of the solder resist layer 140 is formed along the peripheral edge 120a of the surface of the wiring structure 120, similar to the side surface of the solder resist layer 130, and is meandering in a wavy manner.

[0045] As described above, the wiring board assembly according to the embodiment (for example, wiring board assembly 100) has a wiring structure (for example, wiring structure 120) and an outermost insulating layer (for example, solder resist layers 130, 140). The wiring structure consists of a wiring layer (for example, wiring layer 122) and an insulating layer (for example, insulating layer 121). The outermost insulating layer covers the surface of the wiring structure and has slits (for example, slits 132, 142) that expose a predetermined area (for example, cutting area CR) on the surface of the wiring structure. The edges of the outermost insulating layer corresponding to the edges of the slits meander in a wavy manner. As a result, the wiring board assembly according to the embodiment can suppress the occurrence of damage and peeling when cutting.

[0046] Furthermore, the edge of the outermost insulating layer corresponding to the edge of the slit may meander in a wave-like manner, including at least one wave selected from a plurality of interconnected arcs, a triangular wave, a square wave, and a trapezoidal wave. As a result, according to the wiring substrate assembly according to the embodiment, the contact area between the outermost insulating layer (e.g., solder resist layers 130, 140) and the periphery of the cut region on the surface of the wiring structure is reduced. In addition, according to the wiring substrate assembly according to the embodiment, chipping and cracking of the upper surface of the wiring structure can be prevented compared to conventional examples in which the outer periphery of the wiring structure is not covered by the outermost insulating layer.

[0047] Furthermore, the multiple protrusions constituting the edge of the outermost insulating layer may have a top portion at a position in contact with the periphery of a predetermined region. As a result, according to the wiring substrate assembly of the embodiment, the contact area between the outermost insulating layer (for example, solder resist layers 130, 140) and the periphery of the cut region on the surface of the wiring structure can be minimized.

[0048] Furthermore, at least one of the multiple protrusions that constitute the edge of the outermost insulating layer may be of a different size from at least one of the other multiple protrusions. As a result, according to the wiring board assembly of the embodiment, damage and peeling during cutting can be further suppressed.

[0049] Furthermore, the outermost insulating layer may have a plurality of intersecting slits. At least one of the plurality of protrusions (e.g., protrusion 132a1) that constitute the edge of the outermost insulating layer corresponding to the edge of the slit may be positioned opposite the corner formed by the plurality of intersecting slits. As a result, according to the wiring substrate assembly of the embodiment, the occurrence of delamination between the outermost insulating layer (e.g., solder resist layers 130, 140) and the wiring structure can be suppressed near the corner formed by the plurality of intersecting slits. [Explanation of Symbols]

[0050] 100 Wiring board assemblies 100a wiring board 110 Core board 120 Wiring structure 120a Periphery 130, 140 solder resist layers 132, 142 slits 132a Edge 132a1 Convex part CR cutting area

Claims

1. A wiring structure consisting of a wiring layer and an insulating layer, The outermost insulating layer covers the surface of the wiring structure and has slits that expose the cutting region of the surface of the wiring structure to be cut. It has, The edge of the outermost insulating layer corresponding to the edge of the slit is wavy and meandering, The multiple protruding portions that constitute the edge of the outermost insulating layer have their tops at positions that are in contact with the periphery of the cut region. A wiring board assembly characterized by the following features.

2. The edge of the outermost insulating layer is A wave that meanders in a wave-like manner, containing at least one wave selected from a wave consisting of multiple interconnected arcs, a triangular wave, a square wave, and a trapezoidal wave. The wiring board assembly according to feature 1.

3. At least one of the multiple protruding portions that constitute the edge of the outermost insulating layer is The size of at least one of the aforementioned multiple protrusions is different from that of the others. The wiring board assembly according to feature 1.

4. The outermost insulating layer comprises a plurality of slits that intersect each other, At least one of the multiple protruding portions that constitute the edge of the outermost insulating layer is Opposite the corner formed by the multiple intersecting slits The wiring board assembly according to feature 1.

5. The insulating layer located on the surface of the wiring structure is Exposed from between the multiple protrusions that make up the edge of the outermost insulating layer The wiring board assembly according to feature 1.

6. A wiring structure consisting of a wiring layer and an insulating layer, The outermost insulating layer covering the surface of the wiring structure and It has, The outermost insulating layer is Formed along the periphery of the surface of the aforementioned wiring structure, and having a wavy, meandering side surface, The multiple protrusions that make up the side surface of the outermost insulating layer have their tops at positions that are in contact with the periphery of the surface of the wiring structure. A wiring board characterized by the following features.

7. The insulating layer located on the surface of the wiring structure is Exposed from between the multiple protrusions that make up the side surface of the outermost insulating layer The wiring board according to feature 6.

8. A wiring structure consisting of a wiring layer and an insulating layer is formed. An outermost insulating layer is formed that covers the surface of the wiring structure and has slits that expose the cutting region of the surface of the wiring structure to be cut, The process includes cutting the wiring structure in the cut region exposed through the slit to separate it into individual pieces, The step of forming the outermost insulating layer is: The edge of the outermost insulating layer corresponding to the edge of the slit is made to meander in a wavy manner. The multiple protruding portions that constitute the edge of the outermost insulating layer have their tops at positions that are in contact with the periphery of the cut region. A method for manufacturing a wiring board, characterized by the following:

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