Wiring board and method for manufacturing the same

Abstract

This invention discloses a technique for improving the shape quality of the end face of a glass core substrate. [Solution] The wiring board manufacturing method of this embodiment is a wiring board manufacturing method in which a base material of a wiring board having a glass core substrate is divided to manufacture a plurality of wiring boards, comprising: a groove forming step in which a groove for dividing is formed in the glass core substrate of the base material; a resin filling step in which resin is filled into the grooves; and a cutting step in which the base material is cut along the grooves with a cutting tool to divide it into the plurality of wiring boards.

Description

Technical Field

[0001] The present disclosure relates to a wiring board having a glass core board and a method for manufacturing the same.

Background Art

[0002] Conventionally, this type of wiring board is manufactured by cutting a base material formed in a state including a plurality of wiring boards with a dicing saw (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

[0029] , FIGS. 1, 2)

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the wiring board manufactured by the conventional manufacturing method, glass pieces may break off from the end face of the glass core board to form recesses, and the shape quality of the end face of the glass core board may become a problem. In contrast, the present application discloses a technique for improving the shape quality of the end face of the glass core board.

Means for Solving the Problems

[0005] A first aspect of the invention of the present disclosure is a method for manufacturing a wiring board that manufactures a plurality of wiring boards by dividing a base material of a wiring board having a glass core board, the method including: a groove forming step of forming a groove for division in the glass core board of the base material; a resin filling step of filling the groove with resin; and a cutting step of cutting the base material along the groove with a cutting tool to divide the base material into the plurality of wiring boards.

[0006] A second aspect of the invention disclosed herein is a wiring board having a glass core substrate, wherein one end or both ends in the thickness direction of the glass core substrate are covered with a resin on the side surface of the glass core substrate. [Brief explanation of the drawing]

[0007] [Figure 1] Figure 1 is a cross-sectional view of a wiring board according to the first embodiment. [Figure 2] Figure 2 is a plan view of the glass core substrate of the base material. [Figure 3] Figures 3A to 3C are cross-sectional views showing the manufacturing process of the base material for the wiring board. [Figure 4] Figures 4A to 4C are cross-sectional views showing the manufacturing process of the base material for the wiring board. [Figure 5] Figures 5A and 5B are cross-sectional views showing the manufacturing process of the base material for the wiring board. [Figure 6] Figure 6 is a cross-sectional view showing the manufacturing process of the base material for a wiring board. [Figure 7] Figure 7 is a cross-sectional view of the wiring board according to the second embodiment. [Figure 8] Figures 8A to 8C are cross-sectional views showing the manufacturing process of the base material for the wiring board. [Figure 9] Figures 9A to 9C are cross-sectional views showing the manufacturing process of the base material for the wiring board. [Figure 10] Figures 10A and 10B are cross-sectional views showing the manufacturing process of the base material for the wiring board. [Modes for carrying out the invention]

[0008] [First Embodiment] A wiring board 90A according to one embodiment of the present disclosure will be described with reference to Figures 1 to 6. As shown in Figure 1, the wiring board 90A includes, for example, a glass core substrate 10, build-up layers 20 laminated on the front and back surfaces of the glass core substrate 10, and a solder resist layer 30 laminated on the build-up layers 20. The build-up layers 20 include alternatingly laminated insulating layers 21 and conductive layers 22, and via conductors 23 formed between adjacent conductive layers 22 with the insulating layer 21 in between. The solder resist layer 30 includes openings 30H corresponding to pads 24 included in the outermost conductive layer 22.

[0009] The glass core substrate 10 is provided with a plurality of through-holes 11H, and through-hole conductors 12 are formed inside these through-holes 11H. The through-hole conductors 12 are formed, for example, by filling the inside of a metal oxide film 12A and an electroless plating film 12B formed on the inner surface of the through-holes 11H with electrolytic plating 12C. Furthermore, the through-hole conductors 12 are, for example, so-called landless through-holes that do not have through-hole lands, and via conductors 23 are directly connected to the end faces 12M on both sides of the through-hole conductors 12.

[0010] The glass core substrate 10 is made of, for example, quartz glass, borosilicate glass, aluminosilicate glass, or soda-lime glass, and is typically 0.4 to 2 mm thick. The multiple through-hole conductors 12 are tapered towards the axial center, but are not limited to this; for example, they may be columnar in shape, meaning their axial size does not change.

[0011] As shown in Figure 1, one side of the glass core substrate 10 (the lower side in Figure 1) is a vertical surface 13A from an intermediate point in the thickness direction, while the other side (the upper side in Figure 1) is an inclined surface 13B from that intermediate point. Furthermore, the vertical surface 13A and the inclined surface 13B are provided around the entire circumference of the glass core substrate 10, which forms a rectangle in plan view. The inclined surface 13B occupies, for example, about 1 / 2 to 3 / 4 of the thickness direction and is inclined inward, for example, 5 to 20° relative to the vertical surface 13A.

[0012] In this embodiment, the inclined surface 13B is covered by the covering portion 14. The covering portion 14 is made of, for example, a resin 14J without an inorganic filler (such as an epoxy resin, a polyimide resin, an acrylic resin, etc.), and is, for example, of the same type as the resin constituting the insulating layer 21. Further, the side surface 14S of the covering portion 14 is substantially flush with the vertical surface 13A of the glass core substrate 10.

[0013] In the example shown in FIG. 1, the end surface 12M of the through-hole conductor 12 is recessed in a concave shape with respect to both the front and back surfaces of the glass core substrate 10, and the insulating layer 21 and the via conductor 23 on the through-hole conductor 12 bulge toward the glass core substrate 10 corresponding to the end surface 12M. Also, the end surface 14M of the covering portion 14 is recessed in a concave shape, and the insulating layer 21 on the covering portion 14 bulges toward the glass core substrate 10 corresponding to the end surface 14M.

[0014] Note that the end surface 12M of the through-hole conductor 12 and the end surface 14M of the covering portion 14 are recessed in a concave shape, but may be, for example, flat surfaces substantially flush with both the front and back surfaces of the glass core substrate 10.

[0015] Next, a method for manufacturing the wiring substrate 90A shown in FIG. 1 will be described. Here, as shown in FIG. 2, the wiring substrate 90A is obtained by manufacturing a base material 100A formed in a state including a plurality of wiring substrates 90A and then fragmenting the base material 100A. Hereinafter, a method for manufacturing the wiring substrate 90A including the method for manufacturing the base material 100A will be described.

[0016] (1) First, the glass core substrate 10 is prepared. Then, for example, a laser is irradiated from the thickness direction thereof to a predetermined position. As a result, a plurality of modified portions 15A and 15B are formed (see FIG. 3A).

[0017] Here, while the plurality of reformed portions 15A reform the entire thickness direction of the glass core substrate 10, the plurality of reformed portions 15B are reformed only from a midway position in the thickness direction of the glass core substrate 10 to one end side (only the upper side in FIG. 3A). Further, as shown in FIG. 2, the plurality of reformed portions 15A are formed in a dot shape on the glass core substrate 10, whereas the plurality of reformed portions 15B are formed in a grid line shape.

[0018] In this embodiment, for example, a pulse laser is used, but it is not limited thereto, and a near-infrared laser or the like may be used. Further, the laser for forming the reformed portion 15A and the laser for forming the reformed portion 15B may be different in type.

[0019] (2) By an etching process, a plurality of through holes 11H and, for example, a plurality of groove portions 16 having a V-shaped cross section are formed (see FIG. 3B).

[0020] As the etching solution, for example, hydrofluoric acid or a mixed acid in which hydrochloric acid, an aqueous nitric acid solution, etc. are mixed with hydrofluoric acid may be used. Further, it is not limited to wet etching, and dry etching such as sputter etching or reactive ion etching may be used. In the case of anisotropic etching such as the latter, the diameter of the through hole 11H and the width of the groove portion 16 are substantially constant in the axial direction.

[0021] Although an example in which the plurality of groove portions 16 are formed by laser processing and etching has been described, it is not limited thereto, and for example, they may be formed by cutting with a dicing blade.

[0022] (3) Next, for example, the resin 14J is filled into each groove portion 16 by a dispenser, and a coating portion 14 is formed (see FIG. 3C). At this time, since the resin 14J does not contain an inorganic filler, the resin 14J easily spreads throughout the groove portion 16. The upper surface of the coating portion 14 is in a state slightly raised from both the front and back surfaces of the glass core substrate 10.

[0023] (4) Next, a metal oxide film 12A is formed on both the front and back surfaces of the glass core substrate 10, including the upper surface of the covering portion 14, and on the inner surface of the through-hole 11H by a known method (see Figure 4A). For example, a tin oxide film, a zinc oxide film, etc., can be used for the metal oxide film 12A.

[0024] (5) Next, electroless plating is performed to form an electroless plating film 12B on the metal oxide film 12A (see Figure 4B).

[0025] (6) Electrolytic plating is performed using the electroless plating film 12B as a seed layer. As a result, the inside of the through-hole 11H is filled with electrolytic plating 12C to form multiple through-hole conductors 12, and electrolytic plating 12C is laminated on both the front and back surfaces of the glass core substrate 10 (see Figure 4C).

[0026] (7) Next, for example, the metal oxide film 12A, electroless plating film 12B, and electrolytic plating 12C on both the front and back surfaces of the glass core substrate 10 are removed by chemical mechanical polishing (CMP). As a result, as shown in Figure 5A, the end face 12M of the through-hole conductor 12 and the end face 14M of the covering portion 14 become recessed towards the glass core substrate 10.

[0027] Furthermore, the polishing method is not limited to chemical-mechanical polishing; mechanical polishing (e.g., sanding, buffing, etc.) or chemical polishing (e.g., polishing using soluble plasma gas) may also be used. In the case of mechanical or chemical polishing, the end faces 12M of the through-hole conductor 12 and the end faces 14M of the covering portion 14 may become flat surfaces substantially flush with both the front and back ends of the glass core substrate 10.

[0028] (8) Next, by a known method, a plurality of insulating layers 21 and a plurality of conductive layers 22 are alternately laminated on both sides of the glass core substrate 10, and a plurality of via conductors 23 penetrating the insulating layer 21 are formed to obtain a build-up layer 20 (see Figure 5B). The end faces 12M of the plurality of concave through-hole conductors 12 and the end faces 14M of the plurality of covering portions 14 are filled with the resin of the insulating layer 21 when the innermost insulating layer 21 is laminated.

[0029] (9) Next, a solder resist layer 30 having multiple openings 30H is formed. This results in a pad 24 in which a portion of the outermost conductive layer 22 is exposed. With this, the base material 100A is completed.

[0030] (10) Next, as shown in Figure 6, the base material 100A is cut by a cutting tool S (for example, a dicing blade). At this time, the base material 100A is cut along the groove 16. That is, in this embodiment, the thickness of the glass core substrate 10 cut by the cutting tool S is thin, and since the groove 16 is filled with resin 14J, the impact of cutting is less likely to be transmitted to the glass core substrate 10. Then, as the groove 16 is divided, the remaining glass core substrate 10 is cut, and the base material 100A is cut. As a result, as shown in Figure 1, a wiring board 90A is obtained in which a part of the groove 16 remains as an inclined surface 13B, and the inclined surface 13B is covered with a covering portion 14.

[0031] As described above, according to the manufacturing method of the wiring board 90A of this embodiment, grooves 16 are formed in the glass core substrate 10 in advance, and the base material 100A is cut along the grooves 16, making it easier to cut the base material 100A. Furthermore, since the grooves 16 are filled with resin 14J, cracking of the glass core substrate 10 can be suppressed in the process after the formation of the grooves 16, and the impact of cutting is less likely to be transmitted to the glass core substrate 10. Moreover, since the inner surface of the grooves 16 is covered with resin 14J, for example, cracks that occur during the formation of the grooves 16 are less likely to propagate, and glass fragments are less likely to chip from the end face of the wiring board 90A. As a result, according to this embodiment, the shape quality of the end face of the glass core substrate 10 can be improved.

[0032] Furthermore, in the manufacturing method of the wiring board 90A of this embodiment, the grooves 16 are formed by laser processing, which makes it less likely for cracks to occur compared to when the grooves 16 are formed by cutting tools or the like. Moreover, since the grooves 16 can be formed at the same time as the through-holes 11H are formed, production efficiency is improved.

[0033] Furthermore, in this embodiment, since the resin 14J is filled into the groove 16 by a dispenser, an appropriate amount of resin 14J can be easily filled into the groove 16.

[0034] [Second Embodiment] The wiring board 90B of this embodiment is shown in Figure 7 and differs from the wiring board 90B of the first embodiment in that the covering portion 14 is filled with resin 21J of the insulating layer 21 which is laminated on both the front and back surfaces of the glass core substrate 10. The base material 100B of the wiring board 90B of this embodiment is manufactured by the following process.

[0035] (1) A laser is irradiated onto the prepared glass core substrate 10 to form multiple modified portions 15A (see Figure 8A).

[0036] (2) Multiple through-holes 11H are formed by etching (see Figure 8B).

[0037] (3) After a metal oxide film 12A is formed on both the front and back surfaces of the glass core substrate 10 and on the inner surface of the through-hole 11H, an electroless plating film 12B is formed on the metal oxide film 12A. Further electrolytic plating is performed to obtain multiple through-hole conductors 12 (see Figure 8C).

[0038] (4) Next, for example, the metal oxide film 12A, electroless plating film 12B, and electrolytic plating 12C on both the front and back surfaces of the glass core substrate 10 are removed by chemical mechanical polishing (CMP). As a result, as shown in Figure 9A, the end face 12M of the through-hole conductor 12 becomes recessed towards the glass core substrate 10.

[0039] (5) Next, a laser is irradiated to form multiple modified parts 15B (see Figure 9B).

[0040] (6) Multiple grooves 16 are formed by etching (see Figure 9C).

[0041] (7) An insulating film for a build-up substrate is laminated as an insulating layer 21 on both the front and back surfaces of the glass core substrate 10 and then heat-pressed. At this time, each groove 16 is filled with the resin 21J of the insulating layer 21, and the insulating layer 21 and the covering portion 14 are obtained as shown in Figure 10A. Then, for example, a plurality of vias (not shown) are formed by laser processing, and then the conductive layer 22 and via conductors 23 are formed by a known method.

[0042] (8) The process in (7) above is repeated to obtain the build-up layer 20 (see Figure 10B). The subsequent steps are the same as in the first embodiment.

[0043] The wiring board 90B and its manufacturing method in this embodiment also provide the same advantages as in the first embodiment.

[0044] [Other embodiments] In the above embodiment, the via conductor 23 is directly connected to the end face 12M of the through-hole conductor 12 of the so-called landless through-hole. However, the invention is not limited to this configuration, and the through-hole conductor 12 may have a land, and the via conductor 23 may be connected to the land.

[0045] The groove 16 in the above embodiment has, for example, a V-shaped cross-section, but is not limited to this, and may have a U-shaped cross-section, a square groove, or the like.

[0046] In the above embodiment, the wiring boards 90A and 90B are provided with a covering portion 14 only on one end in the thickness direction of the glass core substrate 10. However, the invention is not limited to this, and the covering portion 14 may be provided on both ends in the thickness direction of the glass core substrate 10.

[0047] While this specification and drawings disclose specific examples of the technology included in the claims, the technology described in the claims is not limited to these specific examples, but also includes various modifications and changes to these examples, as well as parts of the examples taken individually. [Explanation of Symbols]

[0048] 10 Glass core substrate 11H Through Hole 12 Through-hole conductors 14 Covering part 14J Resin 15A, 15B Modified section 16 groove 20 Build-up Layers 21 Insulating layer 22 Conductive layer 90A, 90B Wiring Board 100A,100B Base material S cutting tool

Claims

1. In a method for manufacturing a wiring board by dividing the base material of a wiring board having a glass core substrate to manufacture multiple wiring boards, A groove formation step in which a groove for dividing is formed in the glass core substrate of the base material, A resin filling step in which resin is filled into the groove, The process includes a cutting step in which the base material is cut along the groove using a cutting tool to divide it into a plurality of wiring boards.

2. In the method for manufacturing a wiring board according to claim 1, The groove formation step includes: A laser irradiation step is performed in which a laser is irradiated onto the glass core substrate of the base material to form a groove-shaped modified portion, The process includes a modified portion removal step, in which the modified portion is removed by a chemical solution to form the groove portion.

3. In the method for manufacturing a wiring board according to claim 1, In the groove formation step, through holes are formed in the glass core substrate of the base material.

4. In the method for manufacturing a wiring board according to claim 1, In the resin filling step, the resin is filled into the groove by a dispenser.

5. In the method for manufacturing a wiring board according to any one of claims 1 to 4, After the resin filling process, a build-up process is performed in which build-up layers including an insulating layer and a conductive layer are formed on the front and back surfaces of the glass core substrate of the base material. In the cutting process, the glass core substrate is cut together with the build-up layer.

6. A wiring board having a glass core substrate, At one or both ends in the thickness direction of the glass core substrate, the side surface of the glass core substrate is covered with resin.

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