WO2007037075A1

WO2007037075A1 - Process for producing wiring board, and wiring board

Info

Publication number: WO2007037075A1
Application number: PCT/JP2006/316298
Authority: WO
Inventors: Kaoru Ono; Mitsuhiro Watanabe
Original assignee: Ain Co., Ltd.; Multi Inc.; Kanto Gakuin University Surface Engineering Resarch Institute
Priority date: 2005-09-27
Filing date: 2006-08-21
Publication date: 2007-04-05
Also published as: JPWO2007037075A1

Abstract

This invention provides a process for producing wiring board and a wiring board that can realize highly efficient heat radiation and the like. In the production process of a wiring board, a clad material comprising two or more layers of two or more types of metals including electrically conductive first and second metals stacked on top of each other is etched to form a columnar part (16) comprising a second metal (12) on a first metal plate part (11). Next, an insulating resin material is stacked on the plate part (11) for covering the columnar part (16) to form an insulating resin layer (17). The surface of the insulating resin layer (17) is then polished so that the front end of the columnar part (16) is exposed from the insulating resin layer (17). A metal layer (18) for a wiring layer formed of an electrically conductive metal connected to the columnar part (16) is provided on the columnar part (16) on its side remote from the plate part (11).

Description

Specification

Wiring board manufacturing method and wiring board

Technical field

The present invention relates to a method for manufacturing a wiring board and a wiring board.

Background art

Patent Document 1 discloses a heat dissipation mechanism. In this heat dissipating mechanism, the heat dissipating mechanism is constituted by a cooling fan and through holes provided in the motherboard.

[0003] Patent Document 1: Japanese Patent Laid-Open No. 2004-40125 (abstract, etc.)

Disclosure of the invention

Problems to be solved by the invention

[0004] As the wiring board, there is used a wiring board formed by opening a hole in an insulating resin board and mating the inside with copper to connect wiring patterns formed on both surfaces of the insulating resin board. When through hole plating is performed in this way, flux components and the like may blow up from the back side of the wiring board to the front side through the through hole, and may adhere between parts or between the part and the wiring board. In particular, recently, surface-mount type electronic component elements have come to be used, and the space between components and wiring boards has become narrower.

[0005] If the gap between the electronic component element and the wiring board becomes narrow as described above, or if foreign matter adheres between the component and the wiring board, the heat dissipation of the electronic component element becomes worse. For this reason, it is necessary to provide a heat sink or a cooling fan for heat dissipation in the electronic component element. If a heat sink or a cooling fan is provided, the total height required for mounting will be high even if the electronic component element is a low-profile surface mounting type.

[0006] An object of the present invention is to obtain a method of manufacturing a wiring board and a wiring board capable of efficiently radiating heat.

Means for solving the problem

[0007] A method of manufacturing a wiring board according to the present invention includes a clad formed by laminating two or three kinds of metals including a conductive first metal and a second metal in two layers or three or more layers. The material is etched to form a column having a second metal on the first metal plate. A step of forming an insulating resin layer by laminating an insulating resin material on the plate-like part so as to cover the columnar part, and a tip of the columnar part being exposed from the insulating resin layer. Forming a metal layer for a wiring layer made of a conductive metal connected to the columnar part on the side opposite to the plate-like part after polishing the surface of the insulating resin layer.

[0008] By adopting this method, a clad material in which two or three or more kinds of metals including a conductive first metal and a second metal are laminated in two layers or three or more layers is used as an ethyne. To form a columnar portion penetrating the insulating resin layer. Also, the columnar portion is electrically connected to the plate portion and the wiring layer on both sides of the insulating resin layer. The columnar part functions as an interlayer wiring of the wiring board.

[0009] Further, the interlayer wiring formed by etching the clad material can have a columnar structure having a height and a width. Columnar-structured interlayer wiring with height and width efficiently diffuses heat and functions as a heat sink. In addition, a large current can flow. In addition, the interlayer wiring formed by etching the clad material is not mixed with impurities like the metal paste used for bump formation, but metal can be used.

Accordingly, the wiring board manufactured by this method can be provided with a heat sink function that allows a large current to flow and efficiently dissipates heat.

[0011] Another method for manufacturing a wiring board according to the present invention includes two or three or more kinds of metals including a conductive first metal and a second metal laminated in two layers or three or more layers. Etching the clad material to form a columnar portion having a second metal force on the plate-like portion of the first metal, and electrically conductive metal foil sandwiching the insulating grease material between the columnar portion. Pressing from the upper side until it comes into contact with the columnar part to form an insulating resin layer whose surface is covered with metal foil, and wiring made of a conductive metal connected to the columnar part after polishing the surface of the metal foil Forming a metal layer for the layer.

[0012] By adopting this method, a clad material in which two or three or more kinds of metals including a conductive first metal and a second metal are laminated in two layers or three or more layers is used as an etchant. The plate-like portion and the wiring layer are electrically connected to each other by the columnar portion formed by squeezing. A wiring board having a columnar portion penetrating the insulating resin layer as an interlayer wiring can be formed. The interlayer wiring formed by etching the clad material can have a columnar structure with height and width. It can function as a heat sink that diffuses heat efficiently, or it can pass a large current. A wiring board having a heat sink function can be formed by flowing a large current. In addition, the interlayer wiring formed by etching the clad material is not mixed with impurities like the metal paste used for bump formation, but metal can be used.

[0013] Further, the wiring layer made of metal foil is pressed until it contacts the columnar part when forming the insulating resin layer, and metal is formed on the surface thereof. The reliability of the electrical connection between the wiring layer and the columnar part using the metal foil is as high as the reliability of the electrical connection between the plate-like part and the columnar part that are integrated as a clad material. .

[0014] In the method for manufacturing a wiring board according to the present invention, the first metal of the clad material is one or more metals selected from copper, silver, aluminum and alloys containing them, The second metal is selected from nickel, aluminum, tin and alloys containing them, and is one or more metals that can be selectively etched with the first metal. is there.

If this method is employed, the second metal can be formed in a columnar shape while the first metal is in the form of a plate during etching.

[0016] In the method for manufacturing a wiring board according to the present invention, the cladding material further has a three-layer structure in which the second metal is sandwiched between the first metals, and the columnar portion is etched twice. Thus, it is formed on the plate-shaped portion of the first metal.

If this configuration is adopted, the same first metal as that of the plate-like portion can be used for the columnar portion.

[0018] The method for producing a wiring board according to the present invention further includes a step of forming a wiring pattern by removing a part of the metal layer and the plate-like portion by an etching process after forming the metal layer. .

If this method is employed, wiring patterns can be simultaneously formed on the wiring layers and the plate-like portions on both sides of the insulating resin layer. Since the plate-like part integrated with the columnar part as the clad material is used as the wiring layer, the bonding strength between the wiring layer and the columnar part is high.

[0020] A third method for manufacturing a wiring board according to the present invention uses a conductive second metal as a conductive first metal. Etching a clad material having a three-layer structure sandwiched between two metal layers to form a columnar portion made of the second metal and the first metal on the plate portion of the first metal, and an insulating grease material A step of forming an insulating resin layer on the plate-like portion so as to fill the periphery of the columnar portion; A step of forming a metal layer for a wiring layer made of a conductive metal, and a step of removing a part of the metal layer and the plate-like portion by etching to form a wiring layer as a wiring pattern. The

If this method is employed, the plate-like portion and the wiring layer are electrically connected by the columnar portion formed by etching the clad material. It is possible to form a wiring board having a columnar portion penetrating the insulating resin layer as an interlayer wiring. The interlayer wiring formed by etching the clad material can have a columnar structure with a height and width, and can function as a heat sink for efficiently diffusing heat or can pass a large current. A circuit board having a heat sink function can be formed by passing a large current. For the interlayer wiring formed by etching the clad material, impurities such as metal paste used for bump formation are mixed, and a metal that is not a waste can be used. Moreover, a wiring pattern can be simultaneously formed on the wiring layer and the plate-like portion on both sides of the insulating resin layer.

[0022] In the method for manufacturing a wiring board according to the present invention, the metal of the metal layer is the first metal.

If this method is employed, the wiring layers on both sides of the insulating resin layer and the metal of the plate-like portion can be aligned with the first metal. However, the interlayer wiring formed by etching the clad material is not something mixed with impurities like the metal paste used for bump formation! / ヽ, metal can be used. Therefore, by making this first metal a metal used for a general wiring board such as copper, a wiring board having the same electrical characteristics as a general wiring board can have a heat sink function. Can do.

[0024] The wiring board according to the present invention is an interlayer wiring that is manufactured by each of the manufacturing methods of the above-described invention and in which the columnar portion penetrates the insulating resin layer.

By adopting this configuration, it is possible to form an interlayer wiring that connects the wiring layers on both sides of the insulating resin layer and the plate-like portion by etching the clad material. Etching clad material Thus, the interlayer wiring formed can have a columnar structure having a height and a width, and can function as a heat sink for efficiently diffusing heat or flow a large current. A wiring board having a heat sink function can be formed by flowing a large current.

[0026] Another wiring board according to the present invention is formed of an insulating resin layer formed in a flat plate shape and a metal layer eroded by an etching process, and an interlayer wiring penetrating the insulating resin layer and insulating And a wiring layer made of a conductive metal disposed on the surface of the resin layer and connected to the interlayer wiring.

If this configuration is adopted, the interlayer wiring is formed by etching. The interlayer wiring formed by etching can have a columnar structure having a height and a width, and can function as a heat sink that efficiently diffuses heat or allows a large current to flow. A circuit board having a heat sink function can be formed by passing a large current.

[0028] In addition to the configuration of the invention described above, another wiring board according to the present invention has an interlayer wiring force penetrating the insulating resin layer. The width of one surface exposed from the insulating resin layer and the other surface The difference with the width is 1.5 to 2.5 times the height of the inter-layer self-alignment line.

When the interlayer wiring is formed from the metal layer eroded by the etching process, the metal layer is eroded substantially uniformly in the height direction and the width direction of the interlayer wiring. As a result, the difference between the width of one surface of the interlayer wiring exposed from the insulating resin layer and the width of the other surface is 1.5 to 2.5 times the height of the interlayer wiring.

[0030] In addition to the components of the invention described above, another wiring board according to the present invention serves as a heat sink that uses at least a part of the interlayer wiring as a heat diffusion path, and functions as a current path. It is not.

If this configuration is adopted, the heat of the components mounted on the wiring board can be diffused by the wiring board.

The invention's effect

[0032] In the present invention, heat can be radiated efficiently.

Brief Description of Drawings

FIG. 1 is a partial cross-sectional view of a double-sided wiring board according to Embodiment 1 of the present invention.

[Figure 2] Figure 2 shows the first half of the manufacturing process for the double-sided wiring board shown in Figure 1 (until the production of the wiring board substrate). FIG.

FIG. 3 is a diagram showing the latter half of the flow of the manufacturing process of the double-sided wiring board of FIG. 1.

FIG. 4 is a partial cross-sectional view of a double-sided wiring board according to Embodiment 2 of the present invention.

FIG. 5 is a diagram showing the first half of the manufacturing process of the double-sided wiring board shown in FIG. 4 (until the production of the wiring board base material).

Explanation of symbols

[0034] 1 Insulating resin layer

2 Surface wiring layer (wiring layer)

3 Interlayer wiring

4 Back wiring layer (wiring layer)

11 Lower copper layer (first metal, plate-like part)

12 Nickel layer (metal layer eroded by etching, second metal)

13 Upper copper layer (metal layer eroded by etching)

16 Columnar part

17 Insulated grease for build-up (insulated grease)

18 Copper layer (metal plating)

33 Insulated grease

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, a method for manufacturing a wiring board and a wiring board according to the present invention will be described based on the drawings!

. As the wiring board, a double-sided wiring board having wiring patterns on both sides is taken as an example, and the manufacturing method of the wiring board is explained by taking the manufacturing method of the double-sided wiring board as an example.

Embodiment 1.

FIG. 1 is a partial cross-sectional view of a double-sided wiring board according to Embodiment 1 of the present invention. The double-sided wiring board has an insulating resin layer 1, a front surface wiring layer 2 as a wiring layer, an interlayer wiring 3, and a back surface wiring layer 4 as a wiring layer. The heat sink 5 is formed by the front surface wiring layer 2, the interlayer wiring 3, and the back surface wiring layer 4.

[0037] The insulating resin layer 1 is formed by forming an insulating resin material into a flat plate shape. Examples of insulating resin materials include paper phenol resin material, paper epoxy resin material, glass epoxy resin material, Tef port (Registered trademark) grease material.

[0038] The surface wiring layer 2 is a wiring layer formed on the surface of the insulating resin layer 1. The surface wiring layer 2 is made of a conductive metal and has a two-layer structure of the same metal such as copper, silver, aluminum, or an alloy containing them. The surface wiring layer 2 may be a layer having a different metal force. Three or more layers may be used.

The back wiring layer 4 is a wiring layer formed on the surface of the insulating resin layer 1. The back wiring layer 4 is made of a conductive metal and has a two-layer structure of the same metal such as copper, silver, aluminum, or an alloy containing them. The surface wiring layer 2 may be a layer having a different metal force. Three or more layers may be used.

The interlayer wiring 3 is disposed through the insulating resin layer 1. Interlayer wiring 3 has a two-layer structure of different metals such as copper and nickel. In this way, nickel is used for only a part of the interlayer wiring 3 and other conductors are made of copper, so that the electrical characteristics of this wiring board are substantially the same as those of a general wiring board. Become.

FIG. 2 is a diagram showing the first half of the manufacturing process of the double-sided wiring board shown in FIG. 1 (until the production of the wiring board base material). FIG. 3 is a diagram showing the latter half of the flow of the manufacturing process of the double-sided wiring board of FIG.

FIG. 2 (A) is a view showing a partial cross section of a clad material (composite material) used for manufacturing the double-sided wiring board of FIG. The clad material has a three-layer structure in which copper layers 11 and 13 are laminated on both sides of a flat nickel layer 12. The nickel layer 12 has a thickness of 2 micrometers. In FIG. 2A, the upper copper layer (hereinafter simply referred to as the upper copper layer) 13 of the nickel layer 12 which is an intermediate layer has a thickness of 400 micrometers. In FIG. 2A, the lower copper layer (hereinafter simply referred to as the lower copper layer) 11 of the nickel layer 12 has a thickness of 18 micrometers. The upper copper layer 13 may have a thickness of about 500 micrometers.

[0043] The clad material is a laminate of dissimilar metals. When dissimilar metals are stacked, the surface of each metal is first mirror-finished by sputtering in a vacuum. Next, the clad material can be formed by sandwiching these dissimilar metals between rolls and pressing them with the pressure of the rolls. In addition, for example, the clad material may be formed by activating the mirror surface of each metal by plasma cleaning and pressing the activated dissimilar metal with a roll.

In manufacturing the double-sided wiring board of FIG. 1, first, the through-hole pattern of the double-sided wiring board A resist layer 14 is formed on the surface of the upper copper layer 13 as shown in FIG. In FIG. 2B, two resist layers 14 are formed. Also, a resist layer 15 is formed on the back surface of the double-sided wiring board so as to cover the entire surface. The resist layers 14 and 15 may be made of a metal that does not melt by the alkali etching process described later, such as tin. In addition, for example, a dry film such as photosensitive resin may be used. The resist layer 15 can be omitted depending on the etching method.

[0045] After forming the resist layers 14 and 15 on the surfaces of the upper copper layer 13 and the lower copper layer 11, alkali etching is performed. In alkali etching, an ammonia alkali solution is used. Ammonia alkaline liquid does not melt nickel or tin. After selective etching with ammonia / alkaline, the resist layers 14 and 15 are removed. Thereby, as shown in FIG. 2C, the portion of the upper copper layer 13 that is not covered with the resist layer 14 is etched by erosion. In FIG. 2 (C), the upper copper layer 13 is covered with the resist layer 14, and the portion is formed into two trapezoidal columnar shapes.

[0046] After the alkali etching treatment and the resist layer peeling treatment, the nickel layer 12 is etched using a nickel remover as shown in Fig. 2 (D). As a result, a portion of the nickel layer 12 that is not covered with the upper copper layer 13 is etched. In FIG. 2 (D), the nickel layer 12 remains as the base of the upper portion of the upper copper layer 13 under the partial force below the two columnar portions of the upper copper layer 13. When nickel is used for the resist layers 14 and 15 formed in FIG. 2B, the resist layers 14 and 15 may be peeled off simultaneously by this etching process. This reduces the number of processes by one.

[0047] Through the above process, the cross-sectional trapezoidal columnar portion 16 having nickel and copper power is formed on the lower copper layer 11 having a flat plate shape. Nickel can be selectively etched with copper by alkaline etching. The columnar portion 16 can be a conical columnar portion, a pyramidal columnar portion, or various columnar portions such as a columnar portion extending in a direction perpendicular to the paper surface of FIG. In addition, erosion by the etchant proceeds from the top to the bottom of Fig. 2 (D) and in the same way in the horizontal direction. Therefore, the columnar portion 16 formed by etching has a smaller head (upper surface in FIG. 2D) than its bottom (lower surface in FIG. 2D). Ye The width of the head portion of the columnar portion 16 formed by the pinching is narrower by an amount corresponding to about twice the height of the columnar portion than the width of the bottom portion.

[0048] After forming the clad material into the lower copper layer 11 having a flat plate shape and the columnar portion 16 also having nickel and copper force, as shown in FIG. 2 (E), for build-up as an insulating grease material Laminate insulating grease 17. The insulating grease 17 for build-up is laminated to a thickness greater than the height of the columnar part 16. An example of the insulating resin material 17 for buildup is epoxy resin. Laminate build-up insulating resin material 17 using liquid or sheet-like epoxy resin.

[0049] After the build-up insulating resin material 17 is laminated and cured, the surface of the resin is polished. As shown in FIG. 2 (F), the insulating grease material 17 for buildup is polished until the tip of the columnar portion 16 is exposed. Thereby, the insulating resin layer 1 is formed.

[0050] After the build-up insulating grease 17 is polished until the tip of the columnar portion 16 is exposed, the surface flattened by the polishing is roughened, and then copper plating is performed. The surface roughening may be performed at least with respect to the build-up insulating resin material 17 or may be performed by aligning the tips of the columnar portions 16. The copper plating may be performed by, for example, an electrolytic plating method.

As a result, as shown in FIG. 2G, a copper layer 18 as a metal plating is laminated on the surface of the build-up insulating resin material 17 and the tip surface of the columnar portion 16. The copper layer 18 formed by this plating is connected to the columnar portion 16. Further, the flat insulating resin layer 1 is in a state where both surfaces thereof are covered with a lower copper layer 11 having a plate shape and a copper layer 18 formed by copper plating. The copper layers 11 and 18 on both sides of the insulating resin layer 1 are electrically connected by the columnar portions 16. Thereby, the base material for forming a double-sided printed circuit board is formed. This substrate is also a kind of wiring board.

[0052] Thus, after forming the base material connected by the columnar portion 16 corresponding to the through-hole pattern of the double-sided wiring board, the copper layers 11 and 18 on both sides of the insulating resin layer 1, the double-sided wiring board The wiring pattern formation process starts.

In the wiring pattern forming process, first, copper plating is executed. Thereby, as shown in FIG. 3 (A), copper plating 19 and 20 is made on the surfaces of the copper layers 11 and 18 on both sides, and the copper portion becomes thick. On both surfaces of the insulating resin layer 1, copper layers in which copper is made into two layers are formed. The upper wiring layer of the insulating resin layer 1 is a metal layer for the surface wiring layer 2, and the lower wiring layer is This is a metal layer for the backside wiring layer 4. When the thickness of the copper layers 11 and 18 on both sides is sufficient in the base material, this copper plating process is not necessary.

[0054] After copper plating 19, 20 on both sides of the substrate, as shown in Fig. 3 (B), a resist layer 21 is formed on the front and back surfaces of the substrate in a pattern corresponding to the wiring pattern of the double-sided wiring board. , 22 is formed.

[0055] After forming resist layers 21 and 22 corresponding to the wiring pattern on the front and back surfaces of the substrate, an etching process is performed. As a result, as shown in FIG. 3C, only the portions of the copper layers 11 and 19 and the copper layers 18 and 20 on both sides covered by the resist layers 21 and 22 remain on the surface of the force base material.

[0056] After the etching process, the resist layers 21 and 22 are peeled off. As a result, as shown in FIG. 3D, the copper layers 11 and 19 and the copper layers 18 and 20 on both surfaces of the insulating resin layer 1 are formed as wiring patterns. In FIG. 3D, two wiring patterns are formed on the copper layers 18 and 20 on the front surface (upper side) of the insulating resin layer 1, and wiring patterns are formed on the copper layers 11 and 19 on the back surface. The wiring pattern composed of the copper layers 18 and 20 on the surface of the insulating resin layer 1 and the wiring pattern of the copper layers 11 and 19 on the back surface are electrically connected by two columnar portions 16. The double-sided wiring board shown in Fig. 1 is formed.

[0057] As described above, according to the first embodiment, the copper layers 11, 19 on both sides of the insulating resin layer 1 and the wiring pattern force of the copper layers 18, 20 are electrically connected by the columnar portions 16. Printed double-sided printed circuit boards can be manufactured. The columnar portion 16 functions as an interlayer wiring 3 that connects the wiring patterns on both sides.

Note that a resist for plating may be formed in a portion other than the wiring pattern portion from the base material state of the double-sided printed board shown in FIG. 2G, and copper plating may be applied in accordance with the wiring pattern. In this case, next, a resist for etching is formed on the copper-plated wiring pattern portion, and the wiring pattern is left by performing an etching process. Finally, the etching resist is removed. You may make it form a double-sided printed circuit board by this method.

[0059] Further, the manufacturing method of the first embodiment and the double-sided wiring board manufactured thereby have the following various characteristics.

[0060] First, a three-layer clad material in which nickel is sandwiched between copper is etched to form a copper plate A columnar portion 16 is formed on the portion, and this columnar portion 16 is used as an interlayer wiring 3 that electrically connects the wiring layers 2 and 3 on both sides of the insulating resin layer 1. In the case of etching, the columnar portion 16 having a height of several hundred micrometers can be formed by adjusting the etching time. By adjusting the width of the resist layer 14 at the time of etching, it can be formed into a shape having a width wider than a through hole used in a general wiring board. The height of the columnar portion 16 is substantially uniform. The columnar portion 16 can be made of a metal that is not mixed with impurities like the metal paste used for bump formation. When such impurities are mixed, the use of metal increases the reliability.

[0061] On the other hand, for example, when the interlayer wiring is formed by bumps or the like, it is necessary to repeatedly stack the bumps to form the final height of the interlayer wiring, or to form a bump. For example, a metal paste mixed with impurities should be used. For this reason, the interlayer wiring cannot be made of only metal. The manufacturing method of the present embodiment and the double-sided wiring board formed therewith are not limited to these.

Further, the columnar portion 16 composed of the nickel layer 12 and the upper copper layer 13 is a part of a member integrated as a clad material, and is formed on the plate-like copper layer 11. . Therefore, the unity of the three layers, that is, the three layers of copper, nickel, and copper, is very strong. Therefore, the bonding strength between the back surface wiring layer 4 composed of the plate-like lower copper layer 11 and the interlayer wiring 3 as the columnar portion 16 is high.

[0063] Further, the columnar portion 16 as the interlayer wiring 3 is made of nickel only in a part thereof, and most of the columnar portion 16 is formed of copper. The wiring layers 2 and 4 are made of copper. As a result, it has the same electrical characteristics as a general circuit board. The wiring layers 2 and 4 and the interlayer wiring ³ have low resistance.

[0064] Further, the columnar portion 16 can have a columnar structure having a height and a width. Further, by forming the columnar portion 16 with a columnar structure having a height and width, a large current can be passed through the interlayer wiring 3 or heat can be diffused by the interlayer wiring 3. The interlayer wiring 3 capable of diffusing heat functions as a heat sink. The heat of the electronic components mounted on the surface wiring layer 2 is efficiently diffused to the back side of the mounting surface by the inter-layer wiring 3 and is efficiently radiated from the back side of the mounting surface (the back surface wiring layer 4). The back wiring layer 4 may be the mounting surface.

[0065] As a result, a double-sided wiring board having the same electrical characteristics as a general wiring board can be used to pass a larger current than a general printed circuit board or to have a heat sink function. wear.

[0066] When a heat sink is formed on the double-sided wiring board, at least a part of the interlayer wiring 3 may be used as a heat diffusion path, as illustrated as the wiring structure at the center of FIG. . In addition, since the heat sink is built into the double-sided wiring board itself, it is possible to avoid attaching a separate large heat sink to the electronic circuit element mounted on the double-sided wiring board. A thin circuit board can be formed by taking advantage of the low profile of surface-mount type electronic circuit elements. In addition, heat tends to stay between the surface-mount type electronic circuit element and the double-sided wiring board, but heat can be radiated efficiently by using this double-sided wiring board in the part where the heat stays. Therefore, such heat retention can be effectively suppressed.

[0067] Embodiment 2.

FIG. 4 is a partial cross-sectional view of the double-sided wiring board according to Embodiment 2 of the present invention. FIG. 5 is a diagram showing the first half of the manufacturing process of the double-sided wiring board shown in FIG. 4 (until the production of the wiring board substrate). Note that the latter half of the manufacturing process for forming the wiring pattern on the base material is the same as that in FIG. Further, as in the first embodiment, in the latter half of the manufacturing process, after forming a resist for plating, a method of forming a wiring pattern can be employed.

As shown in FIG. 4, the double-sided wiring board according to the second embodiment is similar to the double-sided wiring board shown in FIG. 1 in that the insulating resin layer 1, the surface wiring layer 2, the interlayer wiring 3 and the like. And back wiring layer 4. The insulating resin layer 1, the front surface wiring layer 2, the interlayer wiring 3, and the back surface wiring layer 4 are the same as those in the first embodiment, and the description thereof will be omitted. However, the surface wiring layer 2 has a three-layer structure of copper, and a portion of the surface wiring layer 2 that comes into contact with the interlayer wiring 3 is recessed by compression.

Next, the manufacturing process of the double-sided wiring board of FIG. 4 will be described based on FIG. In FIG. 5, steps (A) to (D) are the same as the steps shown in FIGS. 2 (A) to (D), and a description thereof will be omitted. The columnar portion 16 composed of the nickel layer 12 and the upper copper layer 13 is formed on the flat lower copper layer 11 by the etching process of the nickel layer 12 in FIG.

[0070] A plate-shaped lower copper layer 11, a nickel layer 12 and a columnar portion 16 made of an upper copper layer 13 are provided. After the formation, as shown in FIG. 5 (E), the pre-preder sheet 31 and the copper foil 32 are laminated. The pre-preder sheet 31 is a sheet obtained by impregnating a sheet having glass fiber strength with an insulating resin material and drying it. This is a so-called B-stage seat. Then, a cushion material such as craft paper or a Teflon (registered trademark) plate is placed on the copper foil 32, and is pressed from above the cushion material with a hydraulic press or the like while sucking air. Thereby, the pre-preder sheet 31 is liquefied.

[0071] The copper foil 32 is in contact with the tip of the columnar portion 16, and further pressed as shown in FIG. 5 (F) until the portion of the copper foil 32 that contacts the tip of the columnar portion 16 is deformed. The portion of the copper foil 32 that comes into contact with the columnar portion 16 rises.

[0072] By thus pressing the air while sucking air using the cushion material, the insulating grease material 33 is filled between the copper foil 32 and the lower copper layer 11 having a flat plate shape without a gap. Further, the copper foil 32 is electrically connected to the columnar portion 16. The lower copper layer 11 and the copper foil 32 on both sides of the insulating grease 33 are electrically connected by the columnar portion 16.

In FIG. 5 (F), the tip of the columnar part 16 may break through the copper foil 32. Further, the tip of the columnar portion 16 in the first embodiment is flat like a table. Therefore, the columnar part 16 may not be able to penetrate the pre-preder sheet 31. In such a case, a through-hole may be formed in a part corresponding to the columnar part 16 of the pre-preder sheet 31 in advance, and laminated with the copper foil 32 thereon. The size of the through hole formed at this time may be, for example, larger than the tip of the columnar portion 16. Thereby, even if the tip of the columnar part 16 has a table shape, the pre-preda sheet 31 can be penetrated by the columnar part 16.

[0074] While the tip of the columnar part 16 is in contact with the copper foil 32, the liquid insulating resin material 33 is hardened. Thereby, the insulating resin layer 1 is formed.

[0075] After the insulating resin layer 1 is formed, the surface of the copper foil 32 is polished. Thereby, as shown in FIG. 5 (G), the surface of the copper foil 32 becomes flat. After flattening the surface of the copper foil 32, the surface flattened by polishing is roughened, and then copper plating is performed. For example, copper plating can be performed by the electrolytic plating method.

Thereby, a copper layer 34 is laminated on the surface of the copper foil 32 as shown in FIG. 5 (H). table A base material having a two-layer structure of copper (that is, copper foil 32 and copper layer 34) and a single-layer structure of copper having a lower surface made of lower copper layer 11 is formed. The method for forming the double-sided wiring pattern on the substrate is the same as the step shown in FIG. 3 of Embodiment 1 or the other methods described above, and the description thereof is omitted. The copper layers 32 and 34 on the front surface become the front surface wiring layer 2, and the lower copper layer 11 on the back surface becomes the back surface wiring layer 4. Thereby, the double-sided wiring board shown in FIG. 4 is formed.

[0077] As in the case of each embodiment, as a manufacturing technique for forming an interlayer wiring having a height of several hundred micrometers, there is a so-called buildup method. In this build-up method, first, conductive paste is printed on the copper foil surface of each wiring board to form conical bumps, and then the insulating resin board is sandwiched between the conical bumps. A wiring board is formed. The bumps formed on each wiring board are thrust against the insulating resin board and come into contact with each other within the insulating resin board. Thereby, wiring boards are electrically connected. The conical bump can also be formed by repeating plating and etching. However, repeating plating and etching is very time consuming and costly, which is disadvantageous in manufacturing compared to printing a conductive paste.

However, in this build-up method, the bump needs to be formed in a conical shape in order to protrude from the insulating resin plate. For this reason, it is technically difficult to make the bump wide in the entire height direction. Therefore, with this build-up method, it is extremely difficult to form a wide interlayer wiring that efficiently diffuses heat, as in the above-described embodiments.

As described above, in the second embodiment, as in the first embodiment, the wiring layers 2 and 4 on both surfaces of the insulating resin layer 1 are electrically connected by the columnar portions 16 as the interlayer wiring 3. Connected double-sided printed boards can be manufactured.

In the double-sided wiring board of the second embodiment, the pre-preda sheet 31 and the copper foil 32 are pressed onto the flat lower copper layer 11 on which the columnar portions 16 are formed, and the copper plating is further performed. By doing 34, the wiring layers 2 and 4 and the interlayer wiring 3 are electrically connected. Such a connection method between the wiring layers 2 and 4 and the interlayer wiring 3 has high bonding strength and high reliability. Therefore, as a double-sided wiring board, high reliability similar to that of a general wiring board can be ensured. As a result, double-sided wiring with the same reliability and electrical characteristics as a general wiring board The board can be made to carry a larger current than a general printed circuit board or have a heat sink function.

In Embodiment 2, the surface wiring layer 2 is formed using the copper foil 32. The copper foil 32 has a uniform thickness. Further, since the columnar portions 16 are formed by etching, they are aligned at a uniform height. As a result, the thickness of the double-sided wiring board is substantially uniform. And because of the uniform surface thickness, it is possible to create a structure that efficiently releases heat in the use of a heat sink that requires complicated height adjustment with a countersink surface and a separate heat sink. This eliminates the need for a heat sink and an expensive countersink process, and can provide a high heat dissipation wiring board at a low price.

Each of the above embodiments is an example of a preferred embodiment of the present invention. However, the present invention is not limited to this, and various modifications and changes can be made without departing from the scope of the invention. It can be changed.

For example, in each of the above embodiments, a clad material (composite material) in which both surfaces of nickel are coated with copper is used as a starting material for forming a double-sided wiring board. For example, aluminum, tin, stainless steel, brass, or an alloy containing them may be used instead of nickel. Also, one surface of nickel is coated with copper, the other surface is silver or aluminum, or a clad material coated with an alloy containing them, or a clad material with both surfaces of aluminum coated with copper. May be. In addition, for example, a clad material having a two-layer structure in which one surface of nickel or aluminum is coated with copper, silver, aluminum, or an alloy containing them may be used as a starting material. In the case of this two-layered clad material, for example, the columnar portion 16 may be formed of only copper or silver.

In each of the above embodiments, a double-sided wiring board in which the wiring layers 2 and 4 are formed on both sides of the insulating resin layer 1 is illustrated. In addition to this, for example, even a single-sided wiring board in which a wiring layer (for example, wiring layer 4) is formed on one side of the insulating resin layer 1 or a multilayer substrate having three or more wiring layers is manufactured according to the present invention. It can be formed using a method. In a multi-layer board having three or more wiring layers, the third wiring layer and the insulating resin layer on which the third wiring layer is laminated are, for example, a metal film and an insulating resin in a conventional multilayer wiring board. If it is formed with various manufacturing techniques to laminate materials. [0085] In addition, all interlayer wirings 3 may function only as a heat sink, not as a current path. Further, some interlayer wirings 3 may function as a heat sink and a current path, and other interlayer wirings 3 may function only as a heat sink. No current flows through the interlayer wiring 3 that functions only as a heat sink.

In addition, the surface wiring layer 2 may be formed by a physical vapor deposition method such as PVD, which is not performed by the force treatment performed by the plating process. In addition, although a clad material is used as a starting material, it is not possible to use a clad material. Alternatively, a member with a conductive layer formed by plating or physical vapor deposition can be used as a starting material!

Industrial applicability

The present invention can be used for a wiring board on which an electronic component element is mounted and for manufacturing the wiring board.

Claims

The scope of the claims

[1] A plate of the first metal by etching a clad material in which two or three or more kinds of metals including a conductive first metal and a second metal are laminated in two or more layers. Forming a columnar part having a second metal on the shaped part;

A step of laminating an insulating resin material on the plate-like part so as to cover and exhaust the columnar part, and forming an insulating resin layer;

After polishing the surface of the insulating resin layer so that the tip of the columnar part is exposed from the insulating resin layer, the wiring made of a conductive metal connected to the columnar part on the side opposite to the plate-like part Forming a metal layer for the layer;

A method of manufacturing a wiring board, comprising:

[2] The first metal plate is formed by etching a clad material in which two or three or more kinds of metals including the first conductive metal and the second metal are laminated in two or three layers. Forming a columnar part made of the second metal on the shaped part;

A step of pressing an electrically conductive metal foil sandwiching an insulating resin material from the upper side of the columnar part until it comes into contact with the columnar part to form an insulating resin layer whose surface is covered with the metal foil; A step of forming a metal layer for a wiring layer made of a conductive metal connected to the columnar portion after polishing the surface of the metal foil;

A method of manufacturing a wiring board, comprising:

[3] The first metal of the clad material is one or more selected metals of copper, silver, aluminum, and alloys containing them, and the second metal is nickel, aluminum, or the like. Or at least one metal selected from the group consisting of tin, tin, and an alloy containing them, and capable of selective etching with the first metal. 2. A method for producing a wiring board according to 2.

[4] The clad material has a three-layer structure in which a second metal is sandwiched between first metals,

The method for manufacturing a wiring board according to any one of claims 1 to 3, wherein the columnar portion is formed on the first metal plate-like portion by performing an etching process twice.

5. The method according to claim 1, further comprising a step of forming a wiring pattern by removing a part of the metal layer and the plate-like portion by an etching process after forming the metal layer. 4. The method for producing a wiring board according to claim 1, wherein the deviation is from 1 to 4.

[6] A clad material having a three-layer structure in which a conductive second metal is sandwiched between conductive first metals is etched, and the second metal and the first metal are formed on the plate of the first metal. Forming a columnar portion that is a metal force of

Forming an insulating resin layer on the plate-like portion so that the insulating resin material is buried around the columnar portion;

Forming a metal layer for a wiring layer made of a conductive metal formed on the insulating resin layer and connected to the columnar portion on the side opposite to the plate-shaped portion;

A step of removing a part of the metal layer and the plate-like portion by etching to form a wiring layer as a wiring pattern;

A method of manufacturing a wiring board, comprising:

7. The method for manufacturing a wiring board according to claim 1, wherein the metal of the metal layer is the first metal.

[8] A wiring board manufactured by the manufacturing method according to any one of claims 1 to 7, wherein the columnar portion is an interlayer wiring penetrating an insulating resin layer.

[9] An insulating resin layer formed in a flat plate shape;

An interlayer wiring formed from a metal layer eroded by the etching process and penetrating the insulating resin layer;

A wiring layer made of a conductive metal disposed on the surface of the insulating resin layer and connected to the interlayer wiring;

A wiring board comprising:

[10] In the interlayer wiring penetrating the insulating resin layer, the difference between the width of one surface exposed from the insulating resin layer and the width of the other surface is 1.5-2 of the height of the interlayer wiring. 10. The wiring board according to claim 9, wherein the wiring board is 5 times.

11. The wiring board according to claim 9, wherein at least a part of the interlayer wiring is a heat sink that is used as a heat diffusion path and does not function as a current path.