Method of manufacturing wiring board and wiring board

Abstract

To provide a method of manufacturing a wiring board capable of improving manufacturing efficiency.SOLUTION: A method for manufacturing a wiring board includes a formation step of forming a through-hole penetrating in a plate thickness direction in a first substrate, and a lamination step of sticking the first substrate in which the through-hole is formed to a second substrate to close the through-hole.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] In wiring boards, blind holes (so-called "no-holes") are sometimes formed by countersinking, which involves cutting a hole to a desired depth using a countersink bit. Countersinking is not suitable for mass production because it takes a long time to process, and the processing costs are high. Summary of the Invention [Problem to be solved by the invention]

[0003] A primary object of the present invention is to provide a method for manufacturing a wiring board that can improve manufacturing efficiency, and a wiring board. [Means for solving the problem]

[0004] In order to solve the above problem, one aspect of the present invention provides a method for manufacturing a wiring board, which includes a forming step of forming a through hole penetrating a first substrate in a thickness direction, and a lamination step of bonding the first substrate with the through hole formed therein to a second substrate to close the through hole, thereby making it possible to improve manufacturing efficiency.

[0005] In the above aspect, the method may further include a temporary bonding step of temporarily bonding a prepreg to one main surface of the first substrate, the forming step may form the through-hole penetrating the first substrate and the prepreg, and the laminating step may permanently bond the first substrate and the second substrate with the prepreg. This makes it possible to improve the efficiency of manufacturing by utilizing the temporary bonding and permanent bonding of the prepreg.

[0006] In the above aspect, the heating temperature for temporary bonding of the prepreg is lower than the heating temperature for permanent bonding, which makes it possible to temporarily cure the prepreg to an extent that allows the formation of through holes.

[0007] In the above aspect, the laminating step may include bonding the first substrate and the second substrate, in which the through hole is formed, to form the through hole into a blind hole, thereby improving the efficiency of forming the blind hole.

[0008] In the above aspect, the method may further include a processing step of forming a metallic convex portion on one main surface of the second substrate, and the laminating step may include bonding the first substrate having the through hole formed therein to the second substrate having the convex portion formed therein, and inserting the convex portion into the through hole. This makes it possible to obtain a structure in which the convex portion is inserted into the through hole.

[0009] In the above aspect, the forming step may include forming the through holes simultaneously in the plurality of first substrates that are stacked together, thereby making it possible to improve the efficiency of forming the through holes.

[0010] In the above aspect, the forming step may form the through holes in an elongated shape, which makes it possible to make the elongated through holes uniform in shape.

[0011] In the above aspect, the laminating step may include bonding the first substrate having the through hole and the second substrate with an adhesive sheet, whereby the low fluidity of the adhesive sheet makes it possible to prevent the adhesive from entering the through hole.

[0012] In the above aspect, the laminating step may include stacking a plurality of laminates including the first substrate and the second substrate, each having the through hole formed therein, and pressing the laminates together, thereby making it possible to further improve the efficiency of manufacturing.

[0013] Another aspect of the present invention provides a wiring board including a first substrate having a through hole formed in the thickness direction thereof, and a second substrate bonded to the first substrate having the through hole formed therein, the second substrate having a blind hole formed therein, which makes it possible to make the blind hole have a uniform shape.

[0014] In the above aspect, the electronic component may further be accommodated in the blind hole. In this case, the blind hole has a uniform shape, so that the electronic component can be accommodated in a suitable manner.

[0015] Another aspect of the present invention provides a wiring board comprising: a first substrate having a through hole formed in the thickness direction thereof; and a second substrate having a metal protrusion formed thereon and attached to the first substrate having the through hole formed thereon, the second substrate having a metal protrusion inserted into the through hole. This makes it possible to obtain a structure in which the protrusion is inserted into the through hole. [Effects of the Invention]

[0016] According to the present invention, it is possible to improve the efficiency of manufacturing. [Brief explanation of the drawings]

[0017] [Figure 1] 3A to 3C are diagrams illustrating an example of a method for manufacturing a wiring board according to the first embodiment. [Figure 2] 10A to 10C are diagrams for explaining a through-hole forming step. [Figure 3] 10A to 10C are diagrams for explaining a substrate lamination step. [Figure 4] 1A and 1B are diagrams illustrating examples of wiring substrates. [Figure 5] 1A and 1B are diagrams illustrating an example of a cross-sectional structure of a wiring board. [Figure 6] 10A to 10C are diagrams illustrating an example of a method for manufacturing a wiring board according to a second embodiment. [Figure 7] FIG. 10 is a diagram illustrating a prepreg temporary bonding step. [Figure 8] 10A to 10C are diagrams for explaining a through-hole forming step. [Figure 9] 10A to 10C are diagrams for explaining a substrate lamination step. [Figure 10] 1A and 1B are diagrams illustrating an example of a cross-sectional structure of a wiring board. [Figure 11] 10A to 10C are diagrams illustrating an example of a method for manufacturing a wiring board according to a third embodiment. [Figure 12] 10A to 10C are diagrams for explaining a substrate processing step. [Figure 13] 10A to 10C are diagrams for explaining a substrate lamination step. [Figure 14] 1A and 1B are diagrams illustrating an example of a cross-sectional structure of a wiring board. DETAILED DESCRIPTION OF THE INVENTION

[0018] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In this specification and the drawings, elements similar to those described above with reference to the previous drawings will be designated by the same reference numerals, and detailed descriptions thereof may be omitted as appropriate.

[0019] [First embodiment] Fig. 1 is a flow diagram showing an example of the steps of a method for manufacturing a wiring board. The method for manufacturing a wiring board includes a through-hole forming step S1 and a substrate stacking step S2 as steps for forming a blind hole in a wiring board. Fig. 2 is a diagram for explaining the through-hole forming step S1. Fig. 3 is a diagram for explaining the substrate stacking step S2.

[0020] Fig. 4 is a diagram showing an example of a wiring board 5 manufactured by the wiring board manufacturing method. Fig. 5 is a diagram showing an example of the cross-sectional structure of the wiring board 5. The wiring board 5 includes a first substrate 1 and a second substrate 2 bonded together with an adhesive. These substrates 1 and 2 are formed of, for example, a glass epoxy substrate (a so-called FR-4 substrate).

[0021] As shown in FIG. 2, in the through-hole forming step S1, a through-hole 1a is formed in the first substrate 1 by using a drill D, the through-hole 1a penetrating the first substrate 1 in the thickness direction.

[0022] Drill D is a drill bit (also called a hole-making bit) that is attached to a power tool. Specifically, Drill D is a spiral drill that is suitable for forming through holes and can form holes more quickly than a countersink bit.

[0023] In the through hole forming step S1, through holes 1a are formed all at once in the multiple stacked first substrates 1. That is, a drill D is penetrated all at once through the multiple stacked first substrates 1, thereby forming through holes 1a in each of the multiple first substrates 1. This makes it possible to obtain a large number of first substrates 1 with through holes 1a formed therein at once.

[0024] In the through hole forming step S1, the through hole 1a having an elongated shape is formed. Specifically, the drill D is passed through the workpiece a plurality of times with slight shifts in position, thereby forming the through hole 1a having an elongated shape.

[0025] 3, in the substrate lamination step S2, a first substrate 1 having a through hole 1a formed therein is bonded to a second substrate 2 having no through hole formed therein with an adhesive, thereby converting the through hole 1a into a bottomed hole 5a, and a wiring substrate 5 having the bottomed hole 5a is obtained, as shown in FIGS.

[0026] An adhesive sheet 3 (also called a bonding sheet) is used to bond the first substrate 1 and the second substrate 2. The adhesive sheet 3 is a sheet formed of, for example, an epoxy-based thermosetting adhesive.

[0027] The first substrate 1 and the second substrate 2 sandwiching the adhesive sheet 3 are heat-pressed to harden the adhesive sheet 3, thereby bonding the first substrate 1 and the second substrate 2. The adhesive sheet 3 becomes an adhesive layer 30 when hardened.

[0028] By using adhesive sheet 3 in which the adhesive is solidified and has low fluidity, it is possible to prevent the adhesive from entering through holes 1a even when first substrate 1 and second substrate 2 are hot-pressed.

[0029] In the substrate lamination step S2, a laminate including the first substrate 1 and the second substrate 2 sandwiching the adhesive sheet 3 is stacked in multiple stages and hot-pressed all at once, thereby obtaining a large number of wiring substrates 5 each having a blind hole 5a formed therein.

[0030] 4 and 5, the blind hole 5a is formed by closing one opening of the through hole 1a of the first substrate 1 with the second substrate 2. The bottom of the blind hole 5a is formed of an adhesive layer 30. The blind hole 5a is used to accommodate small electronic components, and contributes to realizing high functionality of the wiring substrate 5.

[0031] According to the present embodiment described above, it is possible to form the blind hole 5a more quickly and easily than by countersinking. Furthermore, according to the present embodiment, it is possible to obtain the blind hole 5a having a more uniform shape than the blind hole obtained by countersinking.

[0032] In particular, when forming a long-hole-shaped bottomed hole, it is difficult to maintain a constant depth using countersinking. However, according to this embodiment, the bottomed hole 5a is obtained by utilizing the through hole 1a, making it possible to maintain a constant depth of the long-hole-shaped bottomed hole 5a.

[0033] The bottom of the bottomed hole 5a is formed by the adhesive layer 30, but this is not limited to this. In the through hole forming process S1, a through hole may be formed in the adhesive sheet 3 as well as the first substrate 1, so that the bottom of the bottomed hole 5a may be formed by the second substrate 2.

[0034] [Second embodiment] A second embodiment will be described. Elements that overlap with those in the above embodiment will be given the same numbers, and detailed descriptions thereof may be omitted.

[0035] 6A and 6B are diagrams illustrating an example of a method for manufacturing a wiring board according to the second embodiment. The method for manufacturing a wiring board includes a prepreg temporary bonding step S11, a through-hole forming step S12, and a substrate lamination step S13.

[0036] Fig. 7 is a diagram illustrating the prepreg temporary bonding step S11. Fig. 8 is a diagram illustrating the through hole forming step S12. Fig. 9 is a diagram illustrating the substrate laminating step S13. Fig. 10 is a diagram illustrating an example of the cross-sectional structure of the wiring substrate 5B.

[0037] The through hole forming step S12 is basically the same as the through hole forming step S1 in the first embodiment. The through hole forming step S12 is basically the same as the substrate stacking step S2 in the first embodiment.

[0038] 7, in the prepreg temporary bonding step S11, a prepreg 6 is temporarily bonded to one main surface of the first substrate 1. The prepreg 6 is a sheet made by impregnating a thermosetting resin such as an epoxy resin into a reinforcing material such as carbon fiber or glass fiber, and bringing it to a semi-cured state.

[0039] The prepreg 6 is temporarily bonded by heating and temporarily curing the prepreg 6. The heating for temporary bonding is performed at a lower temperature than the heating for main bonding, which will be described later.

[0040] The pre-curing of the prepreg 6 is carried out so that the prepreg 6 is in a semi-cured state that is harder than the semi-cured state before heating but harder than the fully cured state. This allows the pre-curing of the prepreg 6 and the formation of the through holes 1a in the next step.

[0041] 8, in the through hole forming step S12, a through hole 1a penetrating the first substrate 1 and the prepreg 6 is formed by a drill D. Instead of using the drill D, a router may be used to form the through hole 1a expanding in the in-plane direction.

[0042] In the through hole forming step S12, through holes 1a are formed in a batch by stacking a plurality of layers of laminates each including a first substrate 1 and a prepreg 6. Also, in the through hole forming step S12, through holes 1a each having an elongated hole shape are formed.

[0043] 9, in the substrate lamination step S13, the first substrate 1 and the second substrate 2 are permanently bonded together using prepreg 6. The permanent bonding of the prepreg 6 is achieved by heating and completely curing the prepreg 6. The heating for the permanent bonding is performed at a higher temperature than the heating for the temporary bonding.

[0044] Specifically, in the substrate lamination process S13, the first substrate 1 and the second substrate 2 sandwiching the prepreg 6 are heated and pressed together, whereby the prepreg 6 is completely cured and the first substrate 1 and the second substrate 2 are bonded together.

[0045] 10, the through holes 1a become bottomed holes 5a, and a wiring board 5B having bottomed holes 5a is obtained. When the prepreg 6 is completely cured, it becomes a resin layer 60 and is integrated with the first substrate 1 and the second substrate 2.

[0046] In the substrate lamination step S13, laminates each including the first substrate 1 and the second substrate 2 sandwiching the prepreg 6 are stacked in multiple stages and hot-pressed together, thereby obtaining a large number of wiring substrates 5B each having a blind hole 5a formed therein.

[0047] In this embodiment, since through holes 1a are formed penetrating first substrate 1 and prepreg 6, it is possible to prevent the resin of prepreg 6 from melting and entering through holes 1a during hot pressing.

[0048] It is preferable that the heating for this bonding be performed at a relatively low temperature within the temperature range that allows complete curing, thereby suppressing the fluidity of the molten resin and preventing the resin from entering the through-hole 1a.

[0049] [Third embodiment] A third embodiment will be described. Elements that overlap with those in the above embodiments will be given the same numbers, and detailed descriptions thereof may be omitted.

[0050] 11 is a diagram illustrating an example of a method for manufacturing a wiring board according to the third embodiment. The method for manufacturing a wiring board includes a prepreg temporary bonding step S11, a through-hole forming step S12, a substrate processing step S23, and a substrate lamination step S24.

[0051] Fig. 12 is a diagram for explaining the substrate processing step S23, Fig. 13 is a diagram for explaining the substrate stacking step S24, and Fig. 14 is a diagram showing an example of the cross-sectional structure of wiring substrate 5C.

[0052] 12, in the substrate processing step S23, a metallic protrusion 25 is formed on one main surface of the second substrate 20. The protrusion 25 has a shape that allows it to be inserted into the through hole 1a formed in the first substrate 1 and the prepreg 6.

[0053] Specifically, the protrusions 25 are formed by partially etching a relatively thick metal layer 22 formed on the underlayer 21 of the second substrate 20. The second substrate 20 is, for example, a so-called thick copper substrate.

[0054] As shown in FIG. 13, in the substrate lamination step S24, a first substrate 1 having a through hole 1a formed therein and a second substrate 20 having a protrusion 25 formed therein are bonded together while inserting the protrusion 25 into the through hole 1a.

[0055] Specifically, in the substrate lamination process S24, the first substrate 1 and the second substrate 20 sandwiching the prepreg 6 are heated and pressed together, whereby the prepreg 6 is completely cured and the first substrate 1 and the second substrate 20 are bonded together.

[0056] As a result, as shown in FIG. 14, metal convex portions 25 of second substrate 20 are inserted into through holes 1a of first substrate 1, and wiring substrate 5C is obtained that appears on the main surface of first substrate 1.

[0057] In this embodiment, the heating for the main bonding is preferably performed at a relatively high temperature within a temperature range that can achieve complete curing, thereby increasing the fluidity of the molten resin and making it possible to fill the gap between the through hole 1a and the protrusion 25.

[0058] Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and it goes without saying that various modifications can be made by those skilled in the art. [Explanation of symbols]

[0059] 1 First board 1a Through hole 2 Second board 3 adhesive sheets 30 Adhesive layer 5. Wiring board 5a Bottomed hole D drill 6 Prepreg 60 resin layer 21 Base layer 23 Metal layer 25 Convex part

Claims

1. a forming step of forming a through hole penetrating through the first substrate in a plate thickness direction; a lamination step of bonding the first substrate having the through hole formed therein to a second substrate to close the through hole; A method for manufacturing a wiring board, comprising:

2. The method further includes a temporary bonding step of temporarily bonding a prepreg to one main surface of the first substrate, the forming step forms the through hole penetrating the first substrate and the prepreg, The lamination step includes actually bonding the first substrate and the second substrate together with the prepreg. The method for manufacturing a wiring board according to claim 1 .

3. The heating temperature for temporary bonding of the prepreg is lower than the heating temperature for main bonding. The method for manufacturing a wiring board according to claim 2 .

4. the laminating step includes bonding the first substrate and the second substrate, in which the through hole is formed, to form the through hole into a bottomed hole; The method for manufacturing a wiring board according to claim 1 .

5. a processing step of forming a metallic convex portion on one main surface of the second substrate, the laminating step includes bonding the first substrate having the through hole formed therein to a second substrate having the convex portion formed therein, and inserting the convex portion into the through hole; The method for manufacturing a wiring board according to claim 1 .

6. the forming step forms the through holes collectively in the plurality of first substrates that are stacked together; The method for manufacturing a wiring board according to claim 1 .

7. In the forming step, the through hole is formed in an elongated hole shape. The method for manufacturing a wiring board according to claim 1 .

8. The laminating step includes bonding the first substrate having the through hole formed therein and the second substrate together with an adhesive sheet. The method for manufacturing a wiring board according to claim 1 .

9. the laminating step includes stacking a plurality of layers of laminates including the first substrate and the second substrate in which the through holes are formed, and pressing the laminates together. The method for manufacturing a wiring board according to claim 1 .

10. a first substrate having a through hole formed in a thickness direction; a second substrate bonded to the first substrate having the through hole formed therein, the second substrate having the through hole as a bottomed hole; A wiring board comprising:

11. Further, an electronic component is accommodated in the blind hole. The wiring board according to claim 10 .

12. a first substrate having a through hole formed in a thickness direction; a second substrate attached to the first substrate having the through hole formed therein, the second substrate having a metal protrusion formed thereon to be inserted into the through hole; A wiring board comprising:

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