JP2021136243A - Multilayer wiring board and manufacturing method of the same - Google Patents

Abstract

To provide a multilayer wiring board with a thin type structure, capable of increasing a ratio of a coil in a cross-sectional area while increasing the number of winding of a coil.SOLUTION: A multilayer wiring board 1 comprises a lamination body 2 on which a plurality of base materials 4 is laminated, and is structured so that a conductive pattern 3a and an inter-lamination connection conductor 3c form a coil. Each layer in the lamination body 2 is adhered with a second thermoset resin 5, and a thermoset resin layer 6 made of a first thermoset resin is interposed between the conductive patter 3a of each layer in the lamination body 2.SELECTED DRAWING: Figure 1

Description

The present invention relates to a multilayer wiring board.

Conventionally, a multilayer substrate in which a thermoplastic resin base material on which a conductor pattern is formed is laminated and heat-bonded has been proposed (Patent Document 1: Japanese Patent No. 6562160). Further, a method for manufacturing a multilayer wiring board in which a multilayer wiring board having a core substrate is formed by a build-up method has been proposed (Patent Document 2: Japanese Patent No. 6274491).

Japanese Patent No. 6562160 Japanese Patent No. 6274491

With the widespread use of personal digital assistants and IoT devices, electronic devices are also required to have a thin structure that can save space. As an example, when a coil formed on a multilayer wiring board is used as an actuator, it is necessary to increase the number of turns of the coil and increase the ratio of the coil in the cross-sectional area in order to increase the thrust of the coil that drives the magnet. However, when the thermoplastic resin base materials are laminated and heat-bonded as in Patent Document 1, there is a risk that the base materials are thermally melted and the conductor pattern is short-circuited between layers, and as the thickness becomes thin, there is a risk of short-circuiting between layers. There is a problem of getting bigger. Further, the build-up method as in Patent Document 2 is used for manufacturing a rigid substrate using a prepreg, and it is sufficiently difficult to reduce the thickness as required for a multi-layer wiring board on which a coil is formed. The reality is that it has not been considered.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a multilayer wiring board capable of having a thinner structure than the conventional one while increasing the number of turns of the coil and increasing the ratio of the coil in the cross-sectional area.

As an embodiment, the problem is solved by a solution means as disclosed below.

The multilayer wiring substrate according to the present invention includes a laminate in which a plurality of substrates are laminated, and has a configuration in which a coil is formed by a conductor pattern and an interlayer connecting conductor, and each layer in the laminate has a second heat. It is characterized in that it is adhered by a curable resin and a thermosetting resin layer made of a first thermosetting resin is interposed between the conductor patterns of each layer in the laminated body.

According to this configuration, each layer is bonded by the second thermosetting resin, and the interlayer insulation of the conductor pattern can be secured by the thermosetting resin layer made of the first thermosetting resin, so that the number of coil turns can be increased. A thin structure can be formed in which the ratio of coils in the cross-sectional area is increased.

The method for manufacturing a multi-layer wiring board according to the present invention is a method for manufacturing a multi-layer wiring board in which a laminated body in which a plurality of base materials are laminated and a coil is formed by a conductor pattern and an interlayer connecting conductor, and each layer is manufactured. With a second thermosetting resin, and having a laminate manufacturing process in which a thermosetting resin layer made of a first thermosetting resin is interposed between the conductor patterns of each layer to form a laminate. It is a feature.

According to this configuration, the coil is formed by adhering each layer with the second thermosetting resin while ensuring the interlayer insulation of the conductor pattern by the thermosetting resin layer made of the first thermosetting resin. It is possible to manufacture a multi-layer wiring board having a thin structure in which the number of turns of the coil is increased and the ratio of coils in the cross-sectional area is increased.

According to the present invention, it is possible to realize a multi-layer wiring board having a thinner structure than the conventional one while increasing the number of turns of the coil and increasing the ratio of the coil in the cross-sectional area.

FIG. 1 is a cross-sectional view schematically showing an example of a multilayer wiring board according to an embodiment of the present invention. FIG. 2A is an example of a method for manufacturing a multilayer wiring board according to the present embodiment, and is a cross-sectional view schematically showing a state in which a peelable copper foil is arranged on a dummy core substrate to form a wiring pattern, and FIG. 2B is FIG. 2A. FIG. 2C is a cross-sectional view schematically showing a state in which a copper foil with resin is arranged following the state of FIG. 2B, and FIG. 2C is a cross-sectional view schematically showing a state in which a wiring pattern is formed following the state of FIG. 2B. FIG. 3A is a cross-sectional view schematically showing a state in which a copper foil with resin is arranged to form a wiring pattern following the state of FIG. 2C, and FIG. 3B shows a laminated body from a dummy core substrate following the state of FIG. 3A. FIG. 3C is a cross-sectional view schematically showing a separated state, and FIG. 3C is a cross-sectional view schematically showing a state in which a peelable copper foil is etched from the separated laminated body following the state of FIG. 3B. FIG. 4 is a structural diagram schematically showing an embodiment of the multilayer wiring board according to the present embodiment. FIG. 5 is an enlarged cross-sectional view showing a VV cross section of the embodiment shown in FIG.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a cross-sectional view schematically showing an example of the multilayer wiring board 1 according to the present embodiment. The multilayer wiring board 1 includes a laminated body 2, and a first conductor pattern 3a and a second conductor pattern 3b are arranged on the laminated body 2. A coil is formed by the conductor pattern 3a, the interlayer connecting conductor 3c, and the conductor pattern 3b. In all the drawings for explaining the embodiment, members having the same function may be designated by the same reference numerals, and the repeated description thereof may be omitted.

As shown in FIG. 1, in the multilayer wiring board 1, plating 8a is formed at the first end of the first conductor pattern 3a on the first main surface side of the laminated body 2 for external connection, and the first A coverlay 7a covers all but the first end of the first conductor pattern 3a on the main surface side. Further, plating 8b is formed at the second end of the second conductor pattern 3b on the second main surface side of the laminated body 2 for external connection, and the second conductor pattern 3b on the second main surface side is formed. Except for the second end of the cover ray 7b. The first conductor pattern 3a and the second conductor pattern 3b are made of copper as an example. The interlayer connecting conductor 3c is made of copper or a copper alloy as an example. Plating 8a and plating 8b are made of nickel, palladium, and gold as an example. The coverlay 7a and the coverlay 7b are made of a polyimide film or a solder resist ink as an example.

In the base material 4, a thermosetting resin layer 6 made of a first thermosetting resin is formed on one side of the first conductor pattern 3a, and an uncured second thermosetting resin 5 is formed on one side of the thermosetting resin layer 6. Is formed, and it is also called a copper foil with resin. The second thermosetting resin 5 is a material different from that of the first thermosetting resin. As an example, the thermosetting resin layer 6 is made of polyimide, and the second thermosetting resin 5 is made of epoxy. As an example, the thermosetting resin layer 6 is made of epoxy, and the second thermosetting resin 5 is made of polyimide.

The present embodiment is a multilayer wiring board 1 in which a coil is formed by a conductor pattern 3a and an interlayer connecting conductor 3c, and each layer in the laminated body 2 is bonded by a second thermosetting resin 5 and laminated. The structure is such that the thermosetting resin layer 6 is interposed between the first conductor pattern 3a and the second conductor pattern 3b of each layer of the body 2. According to this configuration, each layer is bonded by the second thermosetting resin 5, and the interlayer insulation of the first conductor pattern 3a and the second conductor pattern 3b can be ensured by the thermosetting resin layer 6, so that the number of coil turns. It is possible to make a thin structure by increasing the number of coils and increasing the ratio of coils in the cross-sectional area. As an example, the first conductor pattern 3a and the second conductor pattern 3b are made of copper, the second thermosetting resin 5 is made of epoxy, and the thermosetting resin layer 6 is made of polyimide.

As shown in FIG. 1, the total number of layers of the first conductor pattern 3a and the second conductor pattern 3b in the laminated body 2 is 4 or more. According to this configuration, the number of turns of the coil can be sufficiently increased. The number of layers of the first conductor pattern 3a and the second conductor pattern 3b is preferably an even number. According to this configuration, as shown in FIG. 4, since the first end 3a1 and the second end 3b1 of the coil are arranged at the outer edge of the coil-shaped pattern, a wiring circuit for energizing the coil is provided. Can be easily done. As an example, a wiring circuit for energizing the coil is provided in the first conductor pattern 3a in which the first end 3a1 is arranged and the second conductor pattern 3b in which the second end 3b1 is arranged.

The thickness of the thermosetting resin layer 6 is preferably less than 10 [μm], and the thickness of the first conductor pattern 3a is preferably three times or more the thickness of the thermosetting resin layer 6. According to this configuration, a thin and high-thrust coil having a composition ratio of the first conductor pattern 3a in the cross-sectional area in the stacking direction exceeding 40 [%] can be easily formed. The thickness of the thermosetting resin layer 6 is 2 to 5 [μm] as an example, and the thickness of the first conductor pattern 3a is 15 [μm] or more as an example. The configuration is not limited to the above.

The first conductor pattern 3a has a spiral shape in a plan view, and has either a structure in which the width increases and the thickness decreases as the layers are stacked, or a structure in which the width decreases and the thickness increases as the layers are stacked. Is preferable. According to this configuration, it is possible to easily form a thin and high-thrust spiral coil in which the resistance value per cross-sectional area in the first conductor pattern 3a is suppressed to increase with stacking.

Among the conductor patterns, the second conductor pattern 3b on the second main surface side of the laminated body 2 is wired with higher resistance and higher density than the first conductor pattern 3a on the first main surface side of the laminated body 2. Is preferable. According to this configuration, when the second main surface of the laminated body 2 is arranged close to the magnet, the second conductor pattern 3b on the second main surface side of the laminated body 2 is wired at high density, so that it is thin and has high thrust. Is easily obtained.

Subsequently, the method for manufacturing the semiconductor device of the present embodiment will be described below.

The method for manufacturing the multilayer wiring board 1 according to the present embodiment includes a multilayer wiring board 1 in which a plurality of base materials 4 are laminated, and a coil is formed by a conductor pattern 3a and an interlayer connection conductor 3c. It is applied, and each layer is adhered by the second thermosetting resin 5, and the laminated body 2 is formed by interposing the thermosetting resin layer 6 between the first conductor pattern 3a and the second conductor pattern 3b of each layer. It has a laminate manufacturing process. According to this configuration, while ensuring the interlayer insulation of the first conductor pattern 3a and the second conductor pattern 3b by the thermosetting resin layer 6, the layers are laminated by the second thermosetting resin 5 and the laminated body 2 is adhered. Therefore, it is possible to manufacture the multilayer wiring board 1 having a thinner structure than the conventional one while increasing the number of turns of the coil and increasing the ratio of the coil in the cross-sectional area. As an example, the multilayer wiring board 1 is manufactured by a build-up method.

2A to 2C and FIGS. 3A to 3C are examples of the manufacturing procedure of the multilayer wiring board according to the present embodiment. In the laminate manufacturing process, as an example, a dummy core substrate 9 in which the peelable copper foil 11 is arranged on the first main surface and the second main surface opposite to the first main surface is used, and one side of each peelable copper foil 11 is used. The laminated body 2 is formed in each of the above. According to this configuration, the productivity is greatly improved, and the multilayer wiring board 1 having a flat and thin structure can be manufactured. The first main surface and the second main surface show a relative positional relationship, and are not limited to the physical upper surface and lower surface.

First, as shown in FIG. 2A, the peelable copper foil 11 arranged on the first main surface of the dummy core substrate 9 and the peelable copper foil 11 arranged on the second main surface of the dummy core substrate 9 have a second conductor pattern 3b, respectively. To form. A known technique such as ETS technique is applied to the formation of the second conductor pattern 3b.

Next, as shown in FIG. 2B, the base material 4 is arranged in each of the first conductor patterns 3a in FIG. 2A. The base material 4 forms vias at predetermined locations by laser processing. As an example, the base material 4 is formed by applying polyimide to a conductor pattern 3a and thermosetting to form a thermosetting resin layer 6, and further applying an uncured epoxy, which is also called a copper foil with resin. .. Then, as shown in FIG. 2C, the conductor pattern 3a in FIG. 2B is etched to form the first conductor pattern 3a.

Next, as shown in FIG. 3A, the process shown in FIGS. 2B and 2C is repeated to form the laminated body 2, and as shown in FIG. 3B, the laminated body 2 is heat-bonded and then separated from the dummy core substrate 9. do. Then, as shown in FIG. 3C, the peelable copper foil 11 is removed from the separated laminate 2 by an etching process.

After that, as shown in FIG. 1, as an example, the coverslay 7a and the coverlay 7b cover the parts other than the first end and the second end to form the plating 8a and the plating 8b.

(Example)
FIG. 5 is an enlarged cross-sectional view showing a VV cross section of the embodiment shown in FIG. The base material 4 is obtained by applying polyimide to a conductor pattern 3a made of copper and heat-curing it to form a thermosetting resin layer 6, and further coating an uncured epoxy. In the example of FIG. 4, the total number of layers of the first conductor pattern 3a and the second conductor pattern 3b is 4. The second conductor pattern 3b is wired with higher resistance and higher density than the first conductor pattern 3a. Then, the line width of the first conductor pattern 3a is widened as the distance from the second conductor pattern 3b is increased in the stacking direction to reduce the resistance.

In the above example, the configuration is described in which the number of layers of the first conductor pattern 3a and the second conductor pattern 3b is 4 in total, but the present invention is not limited to this, and the number of layers is 3 in total and the number of layers is 5 in total. It is also possible to do the above. In the above example, the laminated body 2 is heat-bonded and then separated from the dummy core substrate 9, but the present invention is not limited to this, and the laminate 2 may be heat-bonded after being separated from the dummy core substrate 9. It is possible. Known processing techniques such as MSAP and ETS can be applied to the formation of the laminate. As described above, the present invention is not limited to the above-described embodiment.

1 Multi-layer wiring board 2 Laminate 3a 1st conductor pattern (conductor pattern)
3b 2nd conductor pattern (conductor pattern)
3c interlayer connection conductor 4 Base material (copper foil with resin)
5 Second thermosetting resin 6 Thermosetting resin layer 7a, 7b Coverlay 8a, 8b Plating 9 Dummy core substrate 11 Peelable copper foil

Claims (7)

It has a structure in which a laminated body in which a plurality of base materials are laminated is provided, and a coil is formed by a conductor pattern and an interlayer connecting conductor.
Each layer in the laminated body is adhered by a second thermosetting resin, and a thermosetting resin layer made of a first thermosetting resin is interposed between the conductor patterns of each layer in the laminated body. A multi-layer wiring board characterized by. In the laminated body, the conductor pattern is used as the first conductor pattern, and the second conductor pattern is further arranged, and the total number of layers of the first conductor pattern and the second conductor pattern is 4 or more. The multilayer wiring board according to claim 1. The multilayer wiring board according to claim 1 or 2, wherein the conductor pattern is made of copper, the second thermosetting resin is epoxy, and the first thermosetting resin is polyimide. The invention according to any one of claims 1 to 3, wherein the thickness of the thermosetting resin layer is less than 10 μm, and the thickness of the conductor pattern is three times or more the thickness of the thermosetting resin layer. Multi-layer wiring board. The conductor pattern has a spiral shape in a plan view, and is characterized in that it has either a structure in which the width increases and the thickness decreases as the layers are stacked, or a structure in which the width decreases and the thickness increases as the layers are stacked. The multilayer wiring board according to claim 4. Among the conductor patterns, the second conductor pattern on the second main surface side of the laminated body is wired with higher resistance and higher density than the first conductor pattern on the first main surface side of the laminated body. The multilayer wiring board according to claim 4 or 5. This is a method for manufacturing a multi-layer wiring board in which a laminated body in which a plurality of base materials are laminated and a coil is formed by a conductor pattern and an interlayer connecting conductor. A method for manufacturing a multilayer wiring board, which comprises a laminate manufacturing process in which a thermosetting resin layer made of a first thermosetting resin is interposed between the conductor patterns of each layer to form a laminate.

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