JP2002368416A - Printed wiring board and manufacturing method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a printed wiring board where an etching processing can be omitted and the danger of environment destruction such as waste liquid treatment is not caused and to provide the manufacturing method. SOLUTION: Conductive paste is applied on a support substrate 2 along a wiring pattern and a paste pattern 3 is formed. The gap of the paste pattern 3 is filled with an insulating material 4, and a first wiring layer where the paste pattern 3 is inserted into an insulating material layer is formed. The surface of the first wiring layer is buff-polished and it is flattened. Then, the upper face of the paste pattern 3 is exposed. Conductor bump groups 5, 5,... are printed and formed on the paste pattern 3. An insulating substrate precursor (prepreg) 6 is overlapped from above and it is heated and pressed. The surface is buff-polished and the head cross sections of the conductor bump groups 5, 5,... are exposed. A paste pattern 7 is applied on them and a second wiring pattern is formed. The similar operation is repeated and a multilayer board-type printed wiring board 1 in the desired number of laminated stages is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printed wiring board, and more particularly to a multilayer printed wiring board in which a plurality of insulating substrates and a plurality of wiring patterns are alternately stacked.

[0002]

2. Description of the Related Art In response to the arrival of the multimedia era, electronic devices such as mobile phones, Internet mobile devices, and mobile personal computers have been put into practical use. There is a demand for cost reduction and the like. As a technique for manufacturing a printed wiring board that satisfies this requirement, attention has been paid to a build-up type multilayer printed wiring board.

[0003] Among them, recently, a wedge-shaped conductive bump formed of a conductive material such as silver paste is inserted in the thickness direction of an insulating substrate precursor (prepreg) to connect wiring patterns between layers. A new build-up multilayer board called "the law" is attracting attention. FIG. 8 is a vertical sectional view illustrating a typical process of the insertion method.

As shown in FIG. 8 (a), a build-up multilayer board by this penetration method is obtained by repeatedly printing a silver paste 3 to 6 times on a copper foil 101 or an inner layer board using a metal screen as shown in FIG. ), A group of conical bumps 102,
The bumped copper foil 103 provided with 102,... Is formed. Next, the synthetic resin sheet (prepreg) 105 is added to the core material 1.
The copper foil with bumps is positioned on the wiring pattern formed on the surface of the core material 110 and fixed thereon so as not to be misaligned with respect to the wiring pattern on the surface of the core material 110. Next, the core material 11 fixed and positioned
0, the synthetic resin-based sheet (prepreg) 105 and the copper foil 103 with bumps are pressed to apply pressure to the bump group 10 in the thickness direction of the synthetic resin-based sheet (prepreg) 105.
Are inserted through the respective bumps 102, 102,..., And the laminated body penetrating the bump groups 102, 102,. . This penetration method has been used for fine-pitch multi-layer printed circuit boards and the like because a through hole can be formed by bumps at a time and a pad-on-via structure can be formed.

[0005]

However, in this penetration method, it is unnecessary to form a wiring pattern by attaching a copper foil, masking the copper foil, and immersing the copper foil in an etching solution. This is performed by a method of removing unnecessary parts, and equipment for etching is required, and there is a problem that manufacturing equipment becomes large. Furthermore, since a waste liquid in which metal ions are dissolved is generated after etching, there is a risk of environmental destruction, and there is a problem that extra equipment for treating the waste liquid is required. Further, there is a problem that a step of etching or drying after hot pressing the prepreg is required, and thus the number of steps is large and complicated.

The present invention is an invention created to solve the above-mentioned conventional problems. That is, an object of the present invention is to provide a printed wiring board which does not require an extra facility such as an etching tank or the like, can omit an etching process, and has no risk of environmental destruction such as waste liquid treatment, and a method for manufacturing the same. .

[0007]

According to the present invention, there is provided a method for manufacturing a printed wiring board, comprising the steps of: forming a first wiring pattern on a supporting base with a conductive paste; and forming an insulating material in a gap between the first wiring pattern. Filling the first wiring pattern into an insulating material layer to form a first wiring layer, and polishing the first wiring layer to form a planar surface Forming a conductive bump on the first wiring pattern; forming a first insulating layer on the conductive bump; polishing the surface of the first insulating layer to form a top of the conductive bump; Exposing a second portion of the first insulating layer with a conductive paste on the exposed portion of the conductor bump head.
Forming the second wiring pattern, and filling the gap between the second wiring patterns with an insulating material to form a second wiring layer in which the second wiring pattern is inserted into the insulating material layer And

According to another method of manufacturing a printed wiring board of the present invention, there are provided (a) a step of forming one wiring pattern on a supporting base with a conductive paste, and (b) an insulating material in a gap between the one wiring pattern. Filling, the one wiring pattern to form one wiring layer penetrated into the insulating material layer,
(C) a step of polishing the one wiring layer to form a planar surface; (d) a step of forming a conductor bump on the one wiring pattern; and (e) a step of forming one conductor on the conductor bump. A step of forming an insulating layer; (f) a step of polishing the surface of the one insulating layer to expose the head of the conductive bump; and A step of forming another wiring pattern with a conductive paste,
(G) filling an insulating material in a gap between the another wiring pattern to form another wiring layer in which the another wiring pattern is inserted into the insulating material layer;
(G) polishing the another wiring layer to form a planar surface, and repeating the above steps (d) to (g) until a predetermined number of stacked bodies is obtained. Features.

According to still another method of manufacturing a printed wiring board of the present invention, a step of forming a first wiring pattern on a supporting base with a conductive paste, and a step of filling a gap between the first wiring patterns with an insulating material. Forming a first wiring layer in which the first wiring pattern is inserted into an insulating material layer;
Polishing the first wiring layer to form a planar surface, forming a conductive bump on the first wiring pattern, and forming a first insulating layer on the conductive bump Polishing the surface of the first insulating layer to expose the conductive bump head, and forming a second wiring pattern with a conductive paste on the conductive bump head exposed portion of the first insulating layer. Forming and filling a gap between the second wiring patterns with an insulating material to form a second wiring layer in which the second wiring pattern is inserted into the insulating material layer. .

In the method of manufacturing a printed wiring board, as an example of the step of forming the insulating layer, a step of heating and pressing after positioning and overlapping the insulating substrate precursor can be mentioned.

In the method for manufacturing a printed wiring board, an example of the step of forming the insulating layer includes a step of applying or applying a liquid or film-like insulating material composition.

A printed wiring board according to the present invention has a first wiring layer in which a first wiring pattern formed of a conductive paste is inserted into an insulating material layer, and a second wiring layer formed of a conductive paste. A second wiring pattern is inserted through the insulating material layer.
A wiring layer, an insulating layer interposed between the first wiring layer and the second wiring layer, and a first wiring pattern interposed between the first wiring pattern and the second wiring layer. A conductive bump electrically connecting the wiring pattern.

In the method of manufacturing a printed wiring board according to the present invention, since the wiring pattern is formed with the conductive paste, no etching equipment is required, and the etching step can be omitted. In addition, since a waste liquid generated by etching is not generated, a method of manufacturing a printed wiring board with less influence on the environment can be provided.

[0014]

Embodiments of the present invention will be described below. FIG. 1 is a flowchart of a method for manufacturing a printed wiring board according to the present embodiment, and FIG. 2 is a vertical cross-sectional view of the printed wiring board according to the present embodiment during manufacturing. To manufacture the printed wiring board according to the present embodiment, first, a wiring pattern is formed using a conductive paste on a support base 2 such as a copper foil, a stainless steel plate, or a resin sheet. That is, by applying or placing a conductive paste on a portion corresponding to the wiring pattern on the support base 2, the wiring pattern is drawn with the conductive paste, and as shown in FIG. A paste pattern 3 is formed as a wiring pattern (step 1).

The conductive paste used here is, for example, a paste in which a predetermined amount of conductive powder or fine particles such as silver powder or copper powder is mixed into a liquid resin such as epoxy resin to impart conductivity. As a method of forming the paste pattern 3, a method of moving the tip of the nozzle along the wiring pattern while discharging the conductive paste from the nozzle, or a template (not shown) in which a portion corresponding to the wiring pattern is punched out of the support base 2. Overlay, apply a conductive paste from above the template, squeeze the conductive paste into the punched part of the template with a spatula, and then peel off the template, or screen printing or A known method such as spraying to form a conductive paste into a wiring pattern may be used.

When the formation of the paste pattern 3 is completed,
An insulating resin 4 is applied from above the support base 2 on which the paste pattern 3 is formed, and as shown in FIG. 2C, the gap between the paste patterns 3 is filled with the insulating resin 4 as an insulating material. . Thus, a first wiring layer as shown in FIG. 2C is formed.

As the insulating resin 4 used here, for example, bisphenol A type polymer, novolak type phenol resin, and dicyandimitide (D
ICY), 2-ethyl-4-methylimidazole as a curing accelerator, and talc, silica, alumina, aluminum hydroxide and magnesium hydroxide as fillers. Further, a glass filler or the like may be mixed as a reinforcing agent.

At the time of application in the above step 2, the insulating resin 4 covers up to the upper surface of the paste pattern 3 as shown in FIG. Therefore, the surface of the insulating resin 4 is polished by buffing or the like after the application of the insulating resin 4 (step 3) to planarize the surface of the insulating resin 4 and expose the upper surface of the paste pattern 3 as shown in FIG. The surface polishing of the insulating resin 4 is preferably performed after the insulating resin 4 is cured. However, even if the insulating resin 4 on the paste pattern 3 is removed by using a spatula or a solvent at the time when the insulating resin 4 is not cured. good.

When the upper surface of the paste pattern 3 is exposed by polishing the surface of the insulating resin 4, the printing technique is used to obtain the paste pattern 3 shown in FIG.
As shown in (e), conductive bump groups 5, 5,... Are formed at predetermined positions on the upper surface of paste pattern 3 (step 4).

At this time, silver powder or copper powder is used as the metal powder contained in the conductive paste constituting the conductor bump groups 5, 5,. The shape may be spherical, scale-like or the like, and a mixture thereof may be used. The method of preparing the conductive paste is adjusted by, for example, mixing these metal powders and a binder component such as a polycarbonate resin, a polysulfone resin, a polyester resin, a phenoxy resin, a phenol resin, and a polyimide resin. The conductive paste can be printed on the copper foil surface or the circuit surface of the inner layer plate using a metal mask plate or the like to easily form the bump group.

The conductor bump groups 5, 5 formed at this time are
It is preferable to form a shape having a bottom surface radius of 100 to 300 μm and a height of 100 to 300 μm on average. This is because if the bottom radius of the conductive bump is smaller than the above range, the reliability of interlayer connection is reduced. If the bottom radius of the conductive bump is larger than the above range, the bottom of the conductive bump protrudes from the width of the paste pattern 3.

When the formation of the conductor bump groups 5, 5,... Is completed, the conductor bump groups 5, 5,.
Then, an insulating layer 6 (first insulating layer) having a predetermined thickness is formed from the bottom surface of step... (Step 5). As a method of forming the insulating layer 6, for example, as shown in FIG. 2 (f), the insulating substrate precursor (prepreg) 6 is aligned and superposed on the heads of the conductor bump groups 5, 5,. Then, the resultant is heated and pressed to form a conductive bump group 5, 5, 5 on the insulating substrate precursor (prepreg) 6.
... and an insulating substrate precursor (prepreg)
6 is cured. In addition, as another method, for example, a liquid insulating resin composition
5, a coating method using a coating device such as a curtain coater, a printing method, and a spraying method.

When the formation of the insulating layer 6 is completed, the heads of the conductor bump groups 5, 5,... Protrude from the upper surface of FIG. Therefore, in the next step, the upper surface of the insulating layer 6 is polished by, for example, a buff (Step 6). By this surface polishing, the upper surface of the insulating layer 6 is planarized, and FIG.
As shown in (a), the heads of the conductor bump groups 5, 5,...
The upper surfaces of 5,... Are exposed in a planar shape.

In this manner, the conductor bump groups 5, 5,... Are stacked on the paste pattern 3 as shown in FIG. A laminate unit is formed. When the layers are further stacked, steps 1 to 6 are repeated to form a desired number of stacked layers (step 7).

For example, when a so-called four-layer plate in which four paste patterns are laminated as a wiring pattern is formed, the head cross sections of the conductor bump groups 5, 5,... Shown in FIG. A second-layer paste pattern 7 is formed on the surface of the insulating layer 6 in the same manner as in Step 1 described above, and an insulating resin 8 is applied thereon in the same manner as in Step 2, and the surface is formed in a manner similar to Step 3. Polish the surface (Fig. 3
(D)) Then, in the same manner as in step 4, the conductive bump groups 9, 9, 9
(FIG. 3 (e)), and then an insulating layer 10 is formed thereon in the same manner as in step 5 (FIGS. 4 (a) to 4 (b)).
(B)) Then, the surface is polished in the same manner as in Step 6 to obtain a two-layer laminate as shown in FIG.

In the same manner, a third-layer paste pattern 11 is formed in the same manner (FIG. 4D), and an insulating resin 12 is applied thereon (FIG. 5A). Polishing is performed to form a three-layer plate as shown in FIG. In this way, the paste pattern and the conductive bumps are stacked, and when the number of layers reaches a predetermined value, the last paste pattern is formed. That is, the third-layer paste pattern 11 and the conductive bump groups 13, 13,... On the third-layer paste pattern 11 are formed, and as shown in FIG. (N-1) Number of stacked layers (n-
When 1 = 3) is reached (step 7), the final fourth-stage paste pattern 15 is formed (FIG. 6C). Thereafter, as shown in FIG. 7A, an insulating resin 15 is applied (Step 9), the surface is polished as shown in FIG. 7B (Step 10), and finally the support base 2 is peeled off. When removed by etching or the like (step 11), FIG.
As shown in (c), four paste patterns 3, 7,
Multilayer board type printed wiring board 1 provided with 11 and 15
Is obtained.

As described above, according to the method of manufacturing a printed wiring board according to the present embodiment, since a wiring pattern (paste pattern) is formed using a conductive paste, etching equipment and etching steps are omitted. be able to. Therefore, no waste liquid is generated by the etching process, and the necessity of the waste liquid treatment and the risk of environmental pollution are prevented beforehand.

In addition, a conductive bump is formed on the surface on which the paste pattern is formed, and the next paste pattern is formed on the surface of the conductive bump by exposing the head of the conductive bump. The connection between the pattern and the conductor bump is reliably formed, and a highly reliable interlayer connection is formed.

Further, after the insulating resin is applied over the paste pattern or the conductive bumps, the surface is polished, and then the next layer is formed, so that the thickness of each layer can be made uniform. Further, when each layer is polished, the thickness can be reduced to a desired thickness, so that a printed wiring board which is thin and has high connection reliability can be manufactured.

The scope of the present invention is not limited to the contents described in the first and second embodiments. For example, in the above embodiment, the conductive paste and the conductive bumps are stacked to form a multilayer board, but a known laminate, for example, two to four wiring layers are alternately laminated with the insulating substrate, and the through holes are formed. It is also possible to use the method of the present invention on a printed wiring board in which conductor bumps and a wiring pattern formed from a conductive paste are sequentially stacked on a wiring layer on the surface of a multilayer board connected between layers to form a multilayer. .

(Second Embodiment) Hereinafter, a method for manufacturing a printed wiring board according to a second embodiment of the present invention will be described. In the method for manufacturing a printed wiring board according to the present embodiment, in order to form the insulating layer 6 in the step 5, the insulating substrate precursor (prepreg) is heated and pressed from above the conductive bump groups 5, 5,. The method in which the conductor bump groups 5, 5,... Are inserted through the insulating substrate precursor (prepreg) 6 is used. The insulating layer 6 was formed by applying the resin composition with a coating device such as a curtain coater. In the present embodiment, the insulating resin composition 4 applied by a coating device such as a curtain coater includes a thermosetting insulating resin, a curing agent, a filler,
It is preferably made of reinforcing fibers or the like.

The thermosetting insulating resin includes an epoxy resin, a polyimide resin and modified resins thereof, and these can be used alone or in combination.

The curing agent can be used without any limitation as long as it is a compound usually used for curing. Examples of the amine curing system include dicyandiamide (DICY) and aromatic diamine. Examples of the phenol curing system include: Phenol novolak resin, cresol novolak resin, bisphenol A type novolak resin and the like can be mentioned, and these can be used alone or in combination of two or more.

Examples of the filler include talc, silica, alumina, aluminum hydroxide, and magnesium hydroxide, and these can be used alone or as a mixture. Here, the preferable range of the compounding amount of the filler is 10 to 50.
Parts by weight. If the amount is less than the above range, necessary mechanical strength cannot be obtained. If the amount exceeds the above range, a filler that is not coated with the insulating resin is generated, and the mechanical strength and the insulating properties are reduced.

Examples of the reinforcing fibers include glass fibers, glass wool, and whiskers, and these can be used alone or in combination. Here, the preferred range of the amount of the reinforcing fiber is 5 to 30 parts by weight. This is because the required mechanical strength cannot be obtained if the ratio is below the range,
If it exceeds the above range, it will protrude from the insulating resin and the mechanical strength and the insulating properties will decrease.

The insulating resin composition 4 has a viscosity of 10 r. p. 25 ° C when measured in m
Is preferably 200 to 300 Pa · s. The reason why the preferable range of the viscosity of the insulating resin composition was set to the above range was that the coating by the curtain coating method could not be successfully performed if the viscosity was below the above range, and the coating was performed by the curtain coating method if the above range was exceeded. This is because the thickness of the coating film sometimes varies and a uniform coating film cannot be obtained.

Further, the thickness of the layer of the insulating resin composition 4 applied by the curtain coater is preferably 30 to 150 μm. If the thickness of the layer of the insulating resin composition 4 is less than the above range, the insulating properties and the reliability of interlayer connection are reduced. If the thickness exceeds the above range, the required integration density cannot be obtained.

In the method for manufacturing a printed wiring board according to the present embodiment, a liquid insulating resin composition is applied from above the conductive bump groups 5, 5,... Formed on the paste pattern to form the insulating layer 6. Therefore, stress hardly acts in the height direction of the conductor bump groups 5, 5,. .. Can be reduced in size, and thereby the insulating layer can be made thinner. Further, since the diameter of the bottom and the head of the conductor bump 5 can be reduced, the pitch of the wiring pattern on the surface of the printed wiring board can be reduced, and the integration density can be increased by increasing the wiring density on the mounting surface. it can.

(Example) Next, an example of the printed wiring board of the present invention will be described. In this example, formation of a two-layer plate was attempted in accordance with the same process as in the above embodiment. As a conductive paste for forming conductive bumps, silver paste (CT
-217K, manufactured by Toshiba Chemical Co., Ltd.). This silver paste is 0.20 mm thick and has a line width of 0.15 m at a predetermined position.
A stainless steel metal mask punched out from a part corresponding to the m circuit pattern is positioned on an 18 μm thick electrolytic copper foil, the silver paste is printed and dried, and then a curtain coating is applied and an epoxy resin composition is applied. did.
Next, the epoxy resin layer was dried and cured, and then buffed to expose the upper surface of the circuit pattern. Furthermore, a 0.20 mm thick stainless steel plate is placed on a predetermined position.
A metal mask having a hole with a diameter of 2 mm was positioned, and a silver paste for bump formation was printed thereon. Then, the printed conductor bump group was dried. Then, FR
-4 prepregs (thickness: 50 μm) were stacked and heated and pressed, and the above-mentioned conductor bump group was inserted into the FR-4 prepreg. After hardening, the surface of FR-4 is buff-polished, and FR-
The head of the conductor bump group protruding from the upper surface of No. 4 was shaved to form a uniform planar surface, and the head of the conductor bump group was exposed as if it were cut along a horizontal plane. Further, a metal mask punching out a portion corresponding to a circuit pattern was overlapped on the exposed cross section of the conductor bump group head, and the silver paste was applied thereon. Next, the metal mask was peeled off, an epoxy resin was applied and cured in the same manner as above, and the surface was buffed. Thereafter, the 18 μm electrolytic copper foil was removed by etching to form a two-layer printed wiring board.

The thickness of this two-layer plate was extremely small, 100 μm, and the diameter of the conductor bump head side in contact with the wiring patterns on both sides was very small, 10 to 50 μm. Therefore, a mounting pattern formed using these wiring patterns can be formed as a very fine pattern having an average pitch of 30 to 100 μm, and a printed wiring board or a semiconductor device with a high degree of integration can be obtained. confirmed.

[0041]

According to the method of manufacturing a printed wiring board of the present invention, since a wiring pattern is formed using a conductive paste, etching equipment is not required and the etching step can be omitted. In addition, since a waste liquid generated by etching is not generated, a method of manufacturing a printed wiring board with less influence on the environment can be provided.

[Brief description of the drawings]

FIG. 1 is a flowchart of a method for manufacturing a printed wiring board according to an embodiment of the present invention.

FIG. 2 is a vertical sectional view of the printed wiring board according to the embodiment of the present invention in the course of manufacturing.

FIG. 3 is a vertical cross-sectional view of the printed wiring board according to the embodiment of the present invention in the course of manufacturing.

FIG. 4 is a vertical sectional view of the printed wiring board according to the embodiment of the present invention in the course of manufacturing.

FIG. 5 is a vertical cross-sectional view of the printed wiring board according to the embodiment of the present invention in the process of being manufactured.

FIG. 6 is a vertical sectional view of the printed wiring board according to the embodiment of the present invention in the course of manufacturing.

FIG. 7 is a vertical cross-sectional view of the printed wiring board according to the embodiment of the present invention in the process of being manufactured.

FIG. 8 is a vertical sectional view showing a manufacturing process of a conventional printed wiring board.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Printed wiring board, 2 ... Support base, 3 ... Paste pattern (first wiring pattern), 4 ... (Insulating material), 5
... conductor bumps, 6 ... insulating layer (first insulating layer), 7 ... paste pattern (second wiring pattern).

 ──────────────────────────────────────────────────の Continuing on the front page (72) Nobuyuki Sato, Inventor 5-14-25 Ryoke, Kawaguchi-shi, Saitama F-term in Kawaguchi Plant of Toshiba Chemical Corporation (reference) 5E346 AA02 AA12 AA15 AA32 AA35 AA51 BB11 BB16 CC08 CC39 DD02 DD13 DD34 EE32 EE35 FF07 FF18 FF24 GG19 GG28 HH11 HH31

Claims (5)

[Claims] A step of forming a first wiring pattern with a conductive paste on a support base; and filling an insulating material in a gap between the first wiring patterns.
A step of forming a first wiring layer in which the first wiring pattern is inserted into an insulating material layer; a step of polishing the first wiring layer to form a planar surface; Forming a conductive bump on the wiring pattern; forming a first insulating layer on the conductive bump; polishing the surface of the first insulating layer to expose the head of the conductive bump; Forming a second wiring pattern with a conductive paste on the exposed portion of the conductor bump head of the first insulating layer; filling an insulating material into a gap between the second wiring patterns;
Forming a second wiring layer in which the second wiring pattern is inserted into an insulating material layer. 2. A step of forming one wiring pattern with a conductive paste on a supporting base; and 2. A filling of an insulating material into a gap between the one wiring pattern to form the one wiring pattern. A step of forming one wiring layer penetrated into the insulating material layer; (c) a step of polishing the one wiring layer to form a planar surface; (E) forming one insulating layer on the conductive bump; and (f) polishing the surface of the one insulating layer to expose the head of the conductive bump. (G) forming another wiring pattern with a conductive paste on the exposed portion of the conductive bump head of the one insulating layer; and (h) filling a gap between the another wiring pattern with an insulating material. Then, the another wiring pattern penetrates through the insulating material layer. Forming another wiring layer, and (g) polishing the other wiring layer to form a planar surface. The above steps are continued until a predetermined number of stacked layers is obtained. A method for manufacturing a printed wiring board, wherein the steps (d) to (g) are repeated. 3. The method for manufacturing a printed wiring board according to claim 1, wherein the step of forming the insulating layer comprises:
A method for manufacturing a printed wiring board, comprising a step of heating and pressing after positioning and overlapping an insulating substrate precursor. 4. The method for manufacturing a printed wiring board according to claim 1, wherein the step of forming the insulating layer comprises:
A method for producing a printed wiring board, which is a step of applying or applying a liquid or film-like insulating material composition. 5. A first wiring layer in which a first wiring pattern formed of a conductive paste is inserted into an insulating material layer, and a second wiring pattern formed of a conductive paste is formed of an insulating material layer. A second wiring layer inserted into the first wiring layer, an insulating layer inserted between the first wiring layer and the second wiring layer, and a first wiring layer inserted into the insulating layer; A printed wiring board, comprising: a conductive bump electrically connecting the wiring pattern to the second wiring pattern.