JP6798537B2 - Circuit board and its manufacturing method - Google Patents

Description

The present invention relates to a circuit board and a method for manufacturing the same.

Circuit boards widely used in electronic devices are required to have finer wiring and higher densities in order to reduce the size and enhance the functionality of electronic devices. As a method for manufacturing a circuit board, a build-up method is known in which insulating layers and conductor layers are alternately stacked on an inner layer board to form a multi-layer wiring structure.

In the method of manufacturing a circuit board by the build-up method, the insulating layer is a resin composition layer in which a resin composition layer is laminated on an inner layer substrate by using, for example, a resin sheet with a support including a support and a resin composition layer. Is formed by thermosetting. Next, a via hole is formed by drilling a hole in the formed insulating layer (see, for example, Patent Document 1).

It is known that the surface roughness of the conductor layer including the wiring is large as one of the factors of the attenuation of the electric signal in the circuit board, and the attenuation of the electric signal due to the large surface roughness of the conductor layer is suppressed. In order to do so, it is desired to reduce the surface roughness of the conductor layer. Especially when a high-frequency electric signal is used, the transmission loss due to the large surface roughness of the conductor layer is remarkable, and especially in a so-called high-frequency circuit board where high-speed transmission of an electric signal is required for a server or the like, the conductor layer It is desired to reduce the surface roughness of the above.

Japanese Unexamined Patent Publication No. 2008-37957

In view of the above points, the present inventors have made the surface roughness of the conductor layer smaller, and the insulating layer of the circuit board in which the thickness of the insulating layer covering the conductor layer is thinner is subjected to via holes by laser irradiation. When the conductor layer is formed, the laser beam is reflected and diffused on the surface of the conductor layer, so that the insulating layer in the vicinity of the conductor layer is scooped out and a scooped portion is inevitably formed. In particular, a via hole having a smaller top diameter is formed. It has been found that, when formed, problems such as cracks in the conductor layer and the insulating layer due to such a hollowed portion may occur over time due to use.

Therefore, an object of the present invention is a case where the surface roughness of the conductor layer is made smaller in a thin circuit board provided with a thinner insulating layer, and a small-diameter via hole is formed in the insulating layer by laser irradiation. Even if there is, it is an object of the present invention to provide a circuit board which is less likely to cause a problem over time due to use such as crack generation.

As a result of diligent studies on the above-mentioned problems, the present inventors set the adhesion strength between the conductor layer and the insulating layer of the circuit board to 0.15 kgf / cm or more, and set the top diameter (Z) of the via hole and the maximum of the via hole. The above problem is that the relationship between the small diameter (Y) and the bottom diameter (X) of the via hole satisfies Y / Z = 0.7 to 0.99 and Y / X = 0.7 to 1 (Z> Y). We have found that we can solve the problem, and have completed the present invention.

That is, the present invention provides the following [1] to [20].
[1] A circuit board comprising a conductor layer and an insulating layer covering the conductor layer, and having a via hole for exposing a part of the conductor layer from the insulating layer.
The arithmetic mean roughness of the surface of the conductor layer is 350 nm or less.
The depth of the via hole is 30 μm or less,
The top diameter (Z) of the via hole is 50 μm or less.
The relationship between the top diameter (Z) of the via hole, the minimum diameter (Y) of the via hole, and the bottom diameter (X) of the via hole is Y / Z = 0.7 to 0.99 and Y / X = 0.7. A circuit board that satisfies ~ 1 (Z> Y).
[2] The circuit board according to [1], wherein the position of the minimum diameter is located closer to the conductor layer with respect to the depth of the via hole.
[3] The circuit board according to [1] or [2], wherein the arithmetic mean roughness of the surface of the conductor layer is 300 nm or less.
[4] The circuit board according to any one of [1] to [3], wherein the depth of the via hole is 25 μm or less.
[5] The circuit board according to any one of [1] to [4], wherein the adhesion strength between the conductor layer and the insulating layer is 0.15 kgf / cm or more.
[6] The circuit board according to any one of [1] to [4], wherein the adhesion strength between the conductor layer and the insulating layer is 0.2 kgf / cm or more.
[7] The circuit board according to any one of [1] to [6], wherein the top diameter (Z) of the via hole is 40 μm or less.
[8] The circuit board according to any one of [1] to [5], wherein the insulating layer is a cured product of the resin composition.
[9] The circuit board according to any one of [1] to [8], wherein the via hole is a via hole formed by irradiating a laser.
[10] A semiconductor device including the circuit board according to any one of [1] to [9].
[11] Step (A) A resin sheet with a plastic film support containing the plastic film support and a resin composition layer bonded to the plastic film support has a surface arithmetic average roughness of 350 nm or less. A step of joining a wiring substrate provided with a conductor layer including a conductor pattern to the conductor layer,
Step (B) The resin composition layer is thermosetting, and the thickness on the conductor layer is 30 μm or less, and the adhesion strength between the insulating layer and the conductor layer is 0.15 kgf / cm or more. The process of forming the insulating layer, which is
Step (C) A via hole having a top diameter (Z) of 50 μm or less in the insulating layer by irradiating a laser from the plastic film support side, and the top diameter (Z) of the via hole and the minimum diameter (Y) of the via hole. ) And the bottom diameter (X) of the via hole satisfying Y / Z = 0.7 to 0.99 and Y / X = 0.7 to 1 (Z> Y). ,
Step (D) The step of performing desmear processing and
Step (E) A step of peeling the plastic film support from the insulating layer,
Step (F) A method for manufacturing a circuit board, which comprises a step of forming a further conductor layer on the insulating layer.
[12] According to [11], in the step (C), the via hole is formed so that the position of the minimum diameter (Y) is located closer to the conductor layer when the depth of the via hole is used as a reference. Circuit board manufacturing method.
[13] The method for manufacturing a circuit board according to [11] or [12], wherein the desmear treatment in the step (D) is a wet desmear treatment.
[14] The step (F) is a step of forming a metal layer on the surface of the insulating layer by dry plating and forming the conductor layer on the surface of the metal layer by wet plating, [11] to [13]. ]. The method for manufacturing a circuit board according to any one of.
[15] The method for manufacturing a circuit board according to any one of [11] to [14], wherein the plastic film support is a plastic film support with a release layer.
[16] The method for producing a circuit board according to any one of [11] to [15], wherein the resin composition layer contains an epoxy resin, a curing agent, and an inorganic filler.
[17] The method for manufacturing a circuit board according to [16], wherein the average particle size of the inorganic filler is 0.01 μm to 3 μm.
[18] The method for manufacturing a circuit board according to [16], wherein the average particle size of the inorganic filler is 0.01 μm to 0.4 μm.
[19] The content of the inorganic filler in the resin composition layer is 40% by mass to 95% by mass when the non-volatile component in the resin composition layer is 100% by mass, [16] to The method for manufacturing a circuit board according to any one of [18].
[20] The method for manufacturing a circuit board according to any one of [16] to [19], wherein the inorganic filler is surface-treated with a surface treatment agent.

According to the present invention, in a circuit board provided with an insulating layer having a thinner thickness covering a conductor layer having a small surface roughness, cracks occur in the conductor layer and the insulating layer even when a via hole having a small diameter is formed by irradiation with a laser. It is possible to provide a circuit board that is less likely to cause problems over time due to use such as laser.

FIG. 1 is a schematic view showing a circuit board in a plane. FIG. 2 is a schematic view showing an end face cut by the II-II alternate long and short dash line in FIG. FIG. 3 is a schematic diagram for explaining a method of manufacturing a circuit board. FIG. 4 is a schematic diagram for explaining a method of manufacturing a circuit board.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. It should be noted that each drawing merely outlines the shape, size and arrangement of the components so that the invention can be understood. The present invention is not limited to the following description, and each component can be appropriately modified without departing from the gist of the present invention. In the drawings used in the following description, similar components may be indicated by the same reference numerals, and duplicate description may be omitted. Further, the configuration according to the embodiment of the present invention is not necessarily manufactured or used in the arrangement and shape shown in the drawing.

[Circuit board including a conductor layer and an insulating layer covering the conductor layer]
The circuit board of the present invention is a circuit board provided with a conductor layer and an insulating layer covering the conductor layer, and provided with via holes for exposing a part of the conductor layer from the insulating layer, and has an arithmetic average roughness on the surface of the conductor layer. Is 350 nm or less, the depth of the via hole is 30 μm or less, the top diameter (Z) of the via hole is 50 μm or less, the top diameter (Z) of the via hole, the minimum diameter (Y) of the via hole, and the bottom diameter of the via hole ( In relation to X), Y / Z = 0.7 to 0.99 and Y / X = 0.7 to 1 (Z> Y) are satisfied.

A configuration example of the circuit board will be described with reference to FIGS. 1 and 2.
FIG. 1 is a schematic view showing a circuit board in a plane. The area where one via hole is provided in the circuit board is enlarged and shown. FIG. 2 is a schematic view showing an end face cut by the II-II alternate long and short dash line in FIG.

As shown in FIGS. 1 and 2, the circuit board 10 of this embodiment includes a wiring board (inner layer board) 20. The wiring board 20 includes a board 22 and a conductor layer 24 provided on the main surface of the board 22. On the side where the conductor layer 24 is provided, an insulating layer 30 is provided to cover the conductor layer 24 and the main surface of the substrate 22 exposed from the conductor layer 24.

In the illustrated example, the conductor layer 24 and the insulating layer 30 are provided only on one main surface side of the substrate 22. However, the configuration of the circuit board 10 according to the present embodiment is not limited to the illustrated example, and the conductor layer 24 and the insulating layer 30 are provided on both side surfaces of the substrate 22, and the build-up layer is provided on both side surfaces of the substrate 22. It may be. In this case, the wiring board 20 corresponds to a so-called inner layer circuit board.

In the following description, in order to simplify the description and facilitate understanding, a configuration in which the conductor layer 24 and the insulating layer 30 are provided only on one main surface side of the substrate 22 will be described.

Here, the surface roughness of the surface 24a of the conductor layer 24, that is, the average roughness (arithmetic mean roughness Ra) is 350 nm or less, preferably 300 nm or less. Therefore, the surface roughness of the conductor layer 24 is made smaller than that of the conventional conductor layer.

The thickness of the insulating layer 30 on the conductor layer 24 according to the present embodiment is 30 μm or less, preferably 25 μm or less. Therefore, the insulating layer 30 is thinner than the insulating layer of the conventional circuit board. That is, the circuit board 10 according to the present invention is characterized in that it is made thinner as a whole.

The details of the method for producing the insulating layer 30 will be described later, but the insulating layer 30 is configured as a cured product of the resin composition. This cured product may be formed by using a prepreg containing a resin composition and a sheet-like fiber base material.

The circuit board 10 is provided with one or more via holes 40 from the surface 30a of the insulating layer 30 to the surface 24a of the conductor layer 24 to expose a part thereof. In the present embodiment, the via hole 40 has a top diameter (Z) of 50 μm or less, preferably 40 μm or less, which is a diameter (opening diameter) of a substantially circular contour defined on the surface 30a of the insulating layer 30. In other words, the via hole 40 provided in the circuit board 10 of the present invention is provided as a via hole having a top diameter (Z) which is the maximum diameter when viewed in the thickness direction of the circuit board 10 is smaller than that of the conventional via hole.

The details of the method for forming the via hole 40 will be described later, but it is preferable that the via hole 40 is formed by irradiating the laser.

The via hole 40 of the present embodiment has a Y / Z in the range of 0.7 to 0.99 (Y / Z) in relation to its top diameter (Z), minimum diameter (Y), and bottom diameter (X) of the via hole. = 0.7 to 0.99), and Y / X is in the range of 0.7 to 1 and Z> Y (Y / X = 0.7 to 1 (Z> Y)).

In the via hole 40 of the present embodiment, the depth d extends in the via hole 40 in a direction orthogonal to the surface 30a of the insulating layer 30 and / or the surface 24a of the conductor layer 24, and one end is on the surface 24a and the other. Corresponds to the length of the line segment whose end is equal to the height of the surface 30a. In the via hole 40, the minimum diameter (Y) is located closer to the conductor layer 24 when the depth d of the via hole 40 is used as a reference. In other words, the position of the minimum diameter (Y) is equal to the position of the top diameter (Z) or the position of the bottom diameter (X) with respect to the depth d of the via hole 40, that is, the position of d / 2. Positions closer to the conductor layer 24, that is, within a range of d / 2 from the bottom 44 (0d) of the via hole 40 on the bottom diameter (X) side with respect to the depth d of the via hole 40, in other words, the top diameter ( It is located within the range of 0.5d to 1.0d from the Z) side.

Here, when the insulating layer 30 is derived from a prepreg and contains a sheet-shaped fiber base material, a position where a part of the sheet-shaped fiber base material protrudes from the insulating layer 30 (side wall of the via hole 40) in the via hole 40 is usually obtained. Corresponds to the minimum diameter (Y).

Normally, the contour shape of the via hole 40 has an inverted truncated cone shape in which the top diameter (Z) is larger than the bottom diameter (X), but the via hole 40 in the illustrated example has a shape from the surface 24a of the conductor layer 24. A hollow portion 42 is formed in a region near the conductor layer 24. The via hole 40 of the present embodiment does not have a hollowed portion 40, the minimum diameter (Y) and the bottom diameter (X) are the same, and the top diameter (Z) is larger than the bottom diameter (X). It may have an inverted truncated cone shape.

The hollowed portion 42 is formed by reflecting and diffusing the laser beam used for forming the via hole 40 on the surface 24a of the conductor layer 24.

In the illustrated example, the hollowed portion 42 has a truncated cone shape in which the diameter of the bottom surface thereof is larger than the diameter of the top surface. However, the shape of the hollowed portion 42 is not limited to this. The maximum diameter of the hollowed portion 42 coincides with the bottom diameter (X) of the bottom portion 44 of the via hole 40 in the illustrated example.

In the circuit board 10, the hollowed portion 42 preferably has a smaller contour diameter (diameter of the bottom surface and the upper surface of the truncated cone) and a smaller size, and the hollowed portion 42 does not exist, that is, Y / X is 1. Therefore, it is more preferable that the contour shape of the via hole 40 is an inverted truncated cone shape.

The adhesion strength between the conductor layer 24 and the insulating layer 30 according to the present embodiment is 0.15 kgf / cm or more, preferably 0.18 kgf / cm or more, and more preferably 0.20 kgf / cm or more. By setting the adhesion strength between the conductor layer 24 and the insulating layer 30 to 0.15 kgf / cm or more in this way, the contour shape of the via hole 40 satisfies the above relationship. As a result, it is possible to form a beer hole 40 in which the diameter of the hollow portion 42 and the size of the hollow portion 42 are smaller even if the hollow portion 42 is not provided or is unavoidably provided. As a result, the circuit board 10 has a long life because it is unlikely to cause problems over time due to use such as cracks in the insulating layer 30 and the conductor layer 24, and is highly reliable even when operated with a high frequency signal, for example. be able to.
On the other hand, when the adhesion strength between the conductor layer 24 and the insulating layer 30 is less than 0.15 kgf / cm, the contour shape of the via hole 40 cannot satisfy the above relationship, and the diameter and size of the hollowed portion 42 become large. Since it becomes large and problems over time due to use such as cracks in the insulating layer 30 and the conductor layer 24 are likely to occur, the characteristics deteriorate over time and the life of the device is shortened. There is a risk.

In the illustrated example, the wiring layer 70 is provided on the surface 30a of the insulating layer 30. The wiring layer 70 is configured as a wiring pattern including a plurality of wirings. Here, the material of the wiring layer 70 is configured as, for example, a filled via so as to fill the inside of the via hole 40, whereby the wiring layer 70 reaches the surface 24a of the conductor layer 24, and the wiring layer 70 and the conductor layer 24 are separated from each other. It is electrically connected.

[Manufacturing method of circuit board]
In the method for manufacturing a circuit board according to the present embodiment, a resin sheet with a plastic film support including the step (A) plastic film support and a resin composition layer bonded to the plastic film support is provided on the surface of the resin sheet. Steps of joining to the conductor layer of a wiring substrate provided with a conductor layer including a conductor pattern having an arithmetic average roughness of 350 nm or less, and step (B) The resin composition layer is heat-cured to have a thickness on the conductor layer. A step of forming an insulating layer having a thickness of 30 μm or less and an adhesion strength between the insulating layer and the conductor layer of 0.15 kgf / cm or more, and step (C) irradiation of a laser from the plastic film support side. The relationship between the top diameter (Z) of the via hole, the minimum diameter (Y) of the via hole, and the bottom diameter (X) of the via hole is Y / Z in the via hole having a top diameter (Z) of 50 μm or less in the insulating layer. A step of forming a via hole satisfying = 0.7 to 0.99 and Y / X = 0.7 to 1 (Z> Y), a step (D) of performing a desmear treatment, and a step (E) of supporting a plastic film. The step includes a step of peeling the body from the insulating layer and a step (F) of forming a further conductor layer on the insulating layer.

A method of manufacturing a circuit board according to the present embodiment will be described with reference to FIGS. 3 and 4. 3 and 4 are schematic views for explaining a method of manufacturing a circuit board shown in the same manner as in FIG.

<Process (A)>
In the step (A), a conductor having a surface arithmetic average roughness of 350 nm or less on a resin sheet with a plastic film support including a plastic film support and a resin composition layer bonded to the plastic film support. This is a step of joining a wiring substrate provided with a conductor layer including a pattern to the conductor layer.

As shown in FIG. 3, in the step (A), a resin sheet 60 with a plastic film support including the plastic film support 50 and the resin composition layer 30X bonded to the plastic film support 50 is prepared. Then, the resin composition layer 30X of the resin sheet 60 with the plastic film support is laminated so as to be bonded to the surface 24a of the conductor layer 24 of the wiring substrate 20.

Examples of the substrate 22 included in the wiring substrate 20 include a glass epoxy substrate, a metal substrate, a polyester substrate, a polyimide substrate, a BT resin substrate, a heat-curable polyphenylene ether substrate, and the like. As described above, a conductor layer (circuit) 24 including one or more patterned wiring patterns is formed on one side (or both sides) of the substrate 22.

The surface roughness of the surface 24a of the conductor layer 24 of the wiring board 20 is such that the average surface roughness (Ra) is 350 nm or less, preferably 300 nm or less, from the viewpoint of reducing the conductor loss of the electric signal. The surface roughness of the conductor layer 24 can be adjusted by surface treatment of the conductor layer 24.

An organic acid-based microetching agent is an example of the surface treatment of the surface 24a of the conductor layer 24, which is preferable from the viewpoint of achieving both the low roughness of the surface 24a of the conductor layer 24 and the adhesion between the conductor layer 24 and the insulating layer 30. Roughening treatment using "Mech Etch Bond CZ8100", "Mech Etch Bond CZ8101" (manufactured by Mech Co., Ltd.), tin-based treatment agent "Secure HFz" (manufactured by Atotech), "Flat Bond" (Mech Co., Ltd.) ) Is used for surface treatment by tin-based treatment. Here, the tin-based treatment means forming a layer containing at least metallic tin or tin oxide on the surface 24a of the conductor layer 24. Specifically, the surface treatment is performed by subjecting the wiring substrate 20 to a treatment such as substitution tin plating or dipping with a treatment liquid containing a tin salt, an organic and / or inorganic acid, a reducing agent, or the like.

Details of the configuration and manufacturing method of the resin sheet 60 with a plastic film support used in the step (A) will be described later.

The bonding (lamination) between the resin sheet 60 with the plastic film support and the wiring board 20 is performed, for example, by a heat-pressing step in which the resin sheet 60 with the plastic film support is heat-bonded to the wiring board 20 from the plastic film support 50 side. It can be carried out. Examples of the member for heat-pressing the resin sheet 60 with the plastic film support to the wiring board 20 (hereinafter, also referred to as “heat-bonding member”) include a heated metal plate (SUS end plate or the like) or a metal roll (SUS roll). ) Etc. can be mentioned. Instead of pressing the heat-bonded member directly onto the resin sheet 60 with the plastic film support, heat-resistant rubber or the like is used as a material so that the resin composition layer 30X sufficiently follows the unevenness of the surface of the circuit board 20. It is preferable to press through an elastic material.

The temperature of the heat crimping step is preferably in the range of 80 ° C. to 160 ° C., more preferably in the range of 90 ° C. to 140 ° C., and further preferably in the range of 100 ° C. to 120 ° C. The pressure in the heat crimping step is preferably in the range of 0.098 MPa to 1.77 MPa, more preferably in the range of 0.29 MPa to 1.47 MPa. The processing time of the heat crimping step is preferably in the range of 20 seconds to 400 seconds, and more preferably in the range of 30 seconds to 300 seconds. Lamination is preferably carried out under reduced pressure conditions where the pressure is 26.7 hPa or less.

Lamination can be performed by a commercially available vacuum laminator. Examples of commercially available vacuum laminators include a vacuum pressurizing laminator manufactured by Meiki Seisakusho Co., Ltd., a vacuum applicator manufactured by Nichigo Morton Co., Ltd., and the like.

In the step (A), the resin sheet 60 with the plastic film support may be laminated on only one side of both main surfaces of the wiring board 20, or may be laminated on both sides.

After the lamination, the laminated resin sheet 60 with the plastic film support may be smoothed by pressing the heat-bonded member under normal pressure (atmospheric pressure) from the side of the plastic film support 50. .. The press conditions for the smoothing treatment can be the same as the conditions in each of the heat crimping steps. The smoothing process can be performed by a commercially available laminator. The lamination and the smoothing treatment may be continuously performed using the above-mentioned commercially available vacuum laminator.

<Process (B)>
In the step (B), the resin composition layer 30X is thermoset, and the insulating layer 30 having a thickness of 30 μm or less on the conductor layer 24 has an adhesive strength of 0.15 kgf between the insulating layer 30 and the conductor layer 24. This is a step of forming the insulating layer 30 of / cm or more.

In the step (B), the resin composition layer 30X is thermally cured to form the insulating layer 30. The plastic film support 50 may be peeled from the resin composition layer 30X before being thermoset. After the insulating layer 30 is formed, the surface 30a of the insulating layer 30 can be easily removed from the surface of the plastic film support 50, such as when the surface of the plastic film support 50 is in contact with the surface of the resin composition layer 30X. When the plastic film support 50 can be peeled off, the insulating layer 30 can be formed by heat-curing the plastic film support 50 as it is without peeling it off.

In the step (B), the thermosetting conditions of the resin composition layer 30X are not particularly limited, but for example, the curing temperature is in the range of 120 ° C. to 240 ° C. (preferably in the range of 150 ° C. to 210 ° C., more preferably 160 ° C.). The curing time can be in the range of 5 minutes to 90 minutes (preferably in the range of 10 minutes to 75 minutes, more preferably in the range of 15 minutes to 60 minutes). The pressure at the time of thermosetting is not particularly limited, and may be under normal pressure, under pressure, or under reduced pressure.

Before the resin composition layer 30X is thermally cured, a preliminary heat treatment may be performed in which the resin composition layer 30X is heat-treated at a temperature lower than the curing temperature. For example, prior to thermosetting the resin composition layer 30X, the resin composition layer 30X is placed at a temperature of 50 ° C. or higher and lower than 120 ° C. (preferably 60 ° C. or higher and 110 ° C. or lower) for 5 minutes or longer (preferably 5 minutes). Pre-heat treatment may be performed for heat treatment (up to 150 minutes).

The thickness of the insulating layer 30 formed by thermosetting the resin composition layer 30X on the conductor layer 24, that is, the depth d of the via hole 40 described above is set to 30 μm or less from the viewpoint of making the thin circuit board 10. From the viewpoint of thinning, the thickness of the insulating layer 30 on the conductor layer 24 is preferably 25 μm or less. The lower limit of the thickness of the insulating layer 30 on the conductor layer 24 is not particularly limited, but is usually 3 μm or more. The thickness t of the insulating layer 30 and the thickness (d) of the insulating layer 30 on the conductor layer 24 are appropriately adjusted by adjusting the thickness of the resin composition layer 30X of the resin sheet 60 with the plastic film support. be able to.

The adhesion strength between the insulating layer 30 and the conductor layer 24 formed by thermosetting the resin composition layer 30X is 0.15 kgf / cm or more. The adhesion strength between the insulating layer 30 and the conductor layer 24 is preferably 0.2 kgf / cm or more. When the adhesion strength is less than 0.15 kgf / cm, when the via hole 40 is formed by laser irradiation, the insulating layer 30 is reflected and diffused by the laser light on the surface 24a of the conductor layer 24 located on the bottom 44 side of the via hole 40. And the conductor layer 24 may be separated by the heat of the laser energy.

The adhesion strength between the formed insulating layer 30 and the conductor layer 24 is a component of the resin composition for forming the insulating layer 30, and curing conditions for forming the insulating layer 30 (resin glass constituting the insulating layer 30). The transition temperature (Tg)), the surface roughness of the surface 24a of the conductor layer 24, the treatment for improving the adhesion of the surface 24a of the conductor layer 24, and the like can be adjusted.

From the viewpoint of adjusting the adhesion strength between the insulating layer 30 and the conductor layer 24, for example, in the components of the resin composition, a resin composition containing an epoxy resin as a main component is used, and a phenol-based curing agent and an active ester-based curing agent are used as curing agents. It is preferable to use an agent. As the curing conditions for such a resin composition, it is preferable to cure under the curing conditions such that the Tg of the cured product of the resin composition is 100 ° C. or higher. When an epoxy resin having a triazine structure or a phenolic curing agent having a triazine structure is used as the material of the resin composition, the adhesion strength between the insulating layer 30 and the conductor layer 24 tends to be improved. On the other hand, when an alicyclic epoxy resin is used as the epoxy resin, the adhesion strength between the insulating layer 30 and the conductor layer 24 tends to decrease, and when a vinyl polymerization resin is used as a component of the resin composition, the adhesion tends to decrease. The strength tends to decrease.

The larger the surface roughness of the surface 24a of the conductor layer 24, the more the adhesion strength between the insulating layer 30 and the conductor layer 24 tends to improve due to the so-called anchor effect. However, the larger the surface roughness of the surface 24a of the conductor layer 24, the more the signal transmission loss tends to increase. Therefore, in the circuit board 10 according to the present embodiment, the surface roughness of the surface 24a of the conductor layer 24 is 350 μm or less. Further, the adhesion strength between the insulating layer 30 and the conductor layer 24 can be improved by performing a surface treatment on the surface 24a of the conductor layer 24 to improve the adhesion strength.

Examples of surface treatments capable of improving the adhesion strength while making the surface 24a of the conductor layer 24 low roughness include "Mech Etch Bond CZ8100" and "Mech Etch Bond CZ8101" (Mech), which are organic acid-based microetchants. Roughing treatment using (manufactured by Co., Ltd.) can be mentioned. Further, as an example of the surface treatment for improving the adhesion strength of the surface 24a of the conductor layer 24, a surface treatment with a tin-based treatment agent "Secure HFz" (manufactured by Atotech) can be mentioned. Further, the adhesion strength may be improved by performing a roughening treatment and a treatment for improving the adhesion strength, and then further performing a treatment using a coupling agent. Examples of the coupling agent that can be used include a silane coupling agent, a titanate-based coupling agent, an aluminate-based coupling agent, and the like. Of these, a silane coupling agent is preferable, and examples of the silane coupling agent include an aminosilane coupling agent, an epoxy silane coupling agent, a styrene silane coupling agent, and the like. Examples of such a surface treatment include a surface treatment by "Flat Bond" (manufactured by MEC Co., Ltd.) including a treatment with a tin-based treatment agent and a treatment using a coupling agent.

In the method of manufacturing the circuit board 10 according to the present embodiment, the via hole 40 is formed in the insulating layer 30. As described above, the top diameter (Z) of the formed via hole 40 is 50 μm or less, and the top diameter (Z) of the via hole 40, the minimum diameter (Y) of the via hole 40, and the bottom diameter (X) of the via hole 40 The relationship is Y / Z = 0.7 to 0.99 and Y / X = 0.7 to 1 (Z> Y). At this time, the position of the minimum diameter of the via hole 40 is located closer to the conductor layer 24 with reference to the depth d of the via hole 40.

<Process (C)>
The circuit board 10 according to this embodiment can be manufactured, for example, by carrying out step (C) after carrying out steps (A) and (B).
In the step (C), the insulating layer 30 is provided with a via hole 40 having a top diameter (Z) of 50 μm or less by irradiating the insulating layer 30 with a laser from the side of the plastic film support 50, that is, above the plastic film support 50. The relationship between the top diameter (Z), the minimum diameter (Y) of the via hole 40, and the bottom diameter (X) of the via hole 40 is Y / Z = 0.7 to 0.99 and Y / X = 0.7. This is a step of forming a via hole 40 satisfying ~ 1 (Z> Y).

As shown in FIG. 4, in the step (C), a laser is irradiated to form a via hole 40 having a top diameter (Z) of 50 μm or less in the insulating layer 30. When the plastic film support 50 exists in a state of being bonded to the insulating layer 30 as shown in the illustrated example, the plastic film support 50 may be irradiated with a laser from above the plastic film support 50. The plastic film support 50 may be peeled off and the insulating layer 30 may be directly irradiated with the laser. From the viewpoint of accurately forming the via hole 40, it is preferable to irradiate the laser from above the plastic film support 50 without peeling it to form the via hole 40.

The top diameter (Z) of the via hole 40 formed in the step (C) is preferably less than 50 μm, more preferably 40 μm or less, from the viewpoint of further increasing the density of the wiring pattern included in the circuit board 10. , 35 μm or less, and particularly preferably 30 μm or less.

The number of via holes 40 formed in the step (C) is not particularly limited, and may be any suitable number depending on the design of the circuit board 10. The top diameters (Z) of the plurality of via holes 40 formed may be the same or different from each other. It is not necessary that all the top diameters (Z) of the via holes 40 formed in the step (C) are 50 μm or less. Depending on the design of the circuit board 10, via holes 40 having a top diameter (Z) of more than 50 μm may be formed together.

The relationship between the top diameter (Z) of the via hole 40 formed by the method for manufacturing the circuit board 10 according to the present embodiment, the minimum diameter (Y) of the via hole 40, and the bottom diameter (X) of the via hole 40 is Y / Z = It is set to 0.7 to 0.99, and Y / X = 0.7 to 1 (Z> Y). The position of the minimum diameter of the via hole 40 is located closer to the conductor layer 24 when the depth d of the via hole 40 is used as a reference.

In step (C), as the laser light source that can be used in the irradiation of the laser, for example, carbon dioxide gas laser, YAG laser, UV-YAG laser, YVO ₄ laser, YLF laser, and an excimer laser or the like. Any suitable laser light source can be used depending on the absorption characteristics of the plastic film support 50 and the insulating layer 30.

The laser irradiation conditions are not particularly limited as long as a small-diameter via hole 40 having a top diameter (Z) as described above can be formed, and the type of laser light source, the presence / absence of the plastic film support 50, its thickness, and the like. It may be appropriately determined according to the thickness, type and the like of the insulating layer 30. Hereinafter, the irradiation conditions when a carbon dioxide laser is used as the laser light source will be described. When a carbon dioxide laser is used as the laser light source, a laser beam having a wavelength of 9.3 μm to 10.6 μm is generally used. The number of shots varies depending on the depth d of the via hole 40 to be formed and the top diameter (Z), but is usually selected in the range of 1 shot to 10 shots. From the viewpoint of increasing the processing speed and improving the productivity of the circuit board, the number of shots is preferably small, preferably in the range of 1 shot to 5 shots, and more preferably in the range of 1 shot to 3 shots. .. When the number of shots is two or more, the laser may be irradiated in either the burst mode or the cycle mode. The energy of the laser depends on the number of shots, the depth d of the via hole 40, the presence / absence of the plastic film support 50, and the thickness thereof, but is preferably 0.2 mJ or more, more preferably 0.3 mJ or more, and further preferably 0. .Set to 4 mJ or more. The upper limit of the energy of the laser is preferably 20 mJ or less, more preferably 15 mJ or less, still more preferably 10 mJ or less.

Step (C) can be carried out using a commercially available laser device. Examples of commercially available laser devices include "LC-2E21B / 1C" (carbon dioxide laser device) manufactured by Hitachi Via Mechanics Co., Ltd. and "605GTWIII (-P)" (carbon dioxide laser device) manufactured by Mitsubishi Electric Corporation. Examples thereof include "MODEL5330xi" and "MODEL5335" (UV-YAG laser apparatus) manufactured by ESI.

A resin residue (smear) is generally attached to the inside of the via hole 40 formed in the step (C) (particularly, the bottom of the via hole 40). Since such smear causes electrical connection failure between layers, a desmear treatment (step (D)) for removing smear is usually performed after the formation of the via hole 40.

<Process (D)>
Step (D) is a step of performing desmear treatment.
In the step (D), the desmear treatment is not particularly limited, and any suitable conventionally known desmear treatment can be performed. The desmear treatment may be performed by, for example, a dry desmear treatment, a wet desmear treatment, or a combination thereof. When the via hole 40 is formed by the laser from above the plastic film support 50, the plastic film support 50 is bonded to the insulating layer 30, but the desmear treatment is performed after the plastic film support 50 is peeled off. It may be carried out in a state of being bonded to the insulating layer 30.

An example of the dry desmear treatment is a desmear treatment using plasma. The desmear treatment using plasma can be carried out using a commercially available plasma desmear treatment apparatus. Among commercially available plasma desmear processing devices, examples suitable for the production of the circuit board of the present invention include a microwave plasma device manufactured by Nissin Co., Ltd., a normal pressure plasma etching device manufactured by Sekisui Chemical Co., Ltd., and the like. Be done.

Another example of the dry desmear treatment is a dry sandblast treatment in which an abrasive can be sprayed from a nozzle to polish the object to be treated. The dry sandblasting treatment can be carried out using a commercially available dry sandblasting treatment apparatus. When a water-soluble abrasive is used as the abrasive, smear can be effectively removed without the abrasive remaining inside the via hole 40 by washing with water after the dry sandblasting treatment. ..

Examples of the wet desmear treatment include desmear treatment using an oxidizing agent solution. When the desmear treatment is performed using the oxidant solution, it is preferable to perform the swelling treatment with the swelling solution, the oxidation treatment with the oxidant solution, and the neutralization treatment with the neutralizing solution in this order. Examples of the swelling liquid include "Swelling Dip Security SBU" and "Swelling Dip Security SBU" manufactured by Atotech Japan Co., Ltd. The swelling treatment is preferably carried out by immersing the substrate on which the via hole 40 is formed in a swelling liquid heated to 60 ° C. to 80 ° C. for 5 to 10 minutes. The oxidizing agent solution is preferably an alkaline permanganate aqueous solution, and examples thereof include a solution in which potassium permanganate or sodium permanganate is dissolved in an aqueous solution of sodium hydroxide. The oxidation treatment with the oxidizing agent solution is preferably carried out by immersing the substrate after the swelling treatment in the oxidizing agent solution heated to 60 ° C. to 80 ° C. for 10 minutes to 30 minutes. Examples of commercially available products of the alkaline permanganate aqueous solution include "Concentrate Compact CP" and "Dosing Solution Security P" manufactured by Atotech Japan Co., Ltd. The neutralization treatment with the neutralizing solution is preferably carried out by immersing the substrate after the oxidation treatment in the neutralizing solution at 30 ° C. to 50 ° C. for 3 to 10 minutes. The neutralizing solution is preferably an acidic aqueous solution, and examples of commercially available products include "Reduction Solution Securigant P" manufactured by Atotech Japan Co., Ltd.

As the wet desmear treatment, a wet sandblasting treatment in which an abrasive and a dispersion medium can be sprayed from a nozzle to polish the object to be treated may also be used. The wet sandblasting treatment can be carried out using a commercially available wet sandblasting treatment apparatus.

When the dry desmear treatment and the wet desmear treatment are carried out in combination, the dry desmear treatment may be carried out first, or the wet desmear treatment may be carried out first.

From the viewpoint of further enjoying the effects of the present invention, the desmear treatment in step (D) is preferably a wet desmear treatment.

<Process (E)>
The step (E) is a step of peeling the plastic film support 50 from the insulating layer 30.
The method of peeling the plastic film support 50 is not particularly limited, and can be performed by any conventionally known suitable method. The plastic film support 50 can be mechanically peeled off by an automatic peeling device.

<Process (F)>
The step (F) is a step of forming the wiring layer 70 on the insulating layer 30.
After the desmear treatment, the wiring layer 70 (build-up wiring layer) is formed on the surface 30a of the insulating layer 30.
The conductor material that can be used for the wiring layer 70 is not particularly limited. In a preferred embodiment, the wiring layer 70 is one or more selected from the group consisting of gold, platinum, palladium, silver, copper, aluminum, cobalt, chromium, zinc, nickel, titanium, tungsten, iron, tin and indium. Metal is included as a material. The wiring layer 70 may be a single metal layer or an alloy layer, and the alloy layer may be, for example, an alloy of two or more metals selected from the above group (for example, nickel-chromium alloy, copper). -A layer formed from a nickel alloy and a copper / titanium alloy) can be mentioned. The wiring layer 70 is a single metal layer of chromium, nickel, titanium, aluminum, zinc, gold, palladium, silver or copper, from the viewpoint of ease of formation, cost, and patterning of the wiring layer 70. It is preferably an alloy layer of nickel-chromium alloy, copper-nickel alloy, copper-titanium alloy, and is a single metal layer of chromium, nickel, titanium, aluminum, zinc, gold, palladium, silver or copper, or nickel-chromium alloy. It is more preferable that it is an alloy layer of, and it is further preferable that it is a single metal layer of copper.

The wiring layer 70 may have a single-layer structure, a single metal layer made of different types of metals or alloys, or a multi-layer structure in which two or more alloy layers are laminated. When the wiring layer 70 has a multi-layer structure, the layer to be joined to the insulating layer 30 is preferably a single metal layer of chromium, zinc or titanium, or an alloy layer of nickel-chromium alloy.

The thickness of the wiring layer 70 depends on the desired circuit board design, but is usually 35 μm or less, preferably 30 μm or less, and more preferably 25 μm or less. The lower limit of the thickness of the wiring layer 70 is not particularly limited, but is usually 3 μm or more, preferably 5 μm or more.

In a preferred embodiment, step (F) is
A step of forming a metal layer on the surface of the insulating layer 30 by dry plating,
The steps of forming the wiring layer 70 on the surface of the metal layer by wet plating are included in this order (hereinafter, referred to as "step (F-1)").

In the step (F-1), first, a metal layer is formed on the surface 30a of the insulating layer 30 by dry plating.

Examples of the dry plating include physical vapor deposition (PVD) methods such as thin film deposition, sputtering, ion plating, and laser ablation, and chemical vapor deposition (CVD) methods such as thermal CVD and plasma CVD, among which vapor deposition, Sputtering is preferred. The metal layer may be formed by combining two of these dry platings.

The thickness of the metal layer to be formed is not particularly limited, but is preferably 5 nm to 2 μm, more preferably 10 nm to 1 μm, and even more preferably 20 nm to 500 nm. The metal layer may have a single layer structure or a multi-layer structure. When the metal layer has a multi-layer structure, the thickness of the entire metal layer is preferably in the above range.

In the step (F-1), after the metal layer is formed, the wiring layer 70 is formed on the surface of the metal layer by wet plating.

Using the metal layer as the plating seed layer, the wiring layer 70 including the wiring pattern having a desired pattern can be formed by wet plating by a semi-additive method. Specifically, a mask pattern is formed on the plating seed layer (metal layer) to expose a part of the plating seed layer corresponding to a desired wiring pattern. After forming the wiring layer 70 by electrolytic plating on the exposed plating seed layer, the mask pattern is removed. After that, the unnecessary plating seed layer can be removed by etching or the like to form the wiring layer 70 including the desired wiring pattern.

In forming the wiring layer 70, the surface 30a of the insulating layer 30 may be roughened. In this case, step (F-1) is
A step of roughening the surface 30a of the insulating layer 30 and
A step of forming a metal layer on the surface 30a of the insulating layer 30 by dry plating, and
The steps of forming the wiring layer 70 on the surface of the metal layer by wet plating are included in this order.

Examples of the roughening treatment include a dry roughening treatment and a wet roughening treatment, and the roughening treatment may be performed by combining these.

The dry roughening treatment can be performed in the same manner as the dry desmear treatment described above. Further, the wet roughening treatment can be performed in the same manner as the wet desmear treatment described above. When the dry roughening treatment and the wet roughening treatment are carried out in combination, the dry roughening treatment may be carried out first, or the wet roughening treatment may be carried out first. The roughening treatment is intended to roughen the exposed surface 30a of the insulating layer 30, but also has a certain effect on removing smear inside the via hole 40. Therefore, even when the step (D) is carried out under mild conditions, it is possible to prevent the smear from remaining.

In other preferred embodiments, step (F) is
A step of roughening the surface 30a of the insulating layer 30 and
The steps of forming the wiring layer 70 by wet plating on the surface 30a of the insulating layer 30 are included in this order (hereinafter, referred to as “step (F-2)”).

The details of the roughening process have already been described.

In the step (F-2), after the surface 30a of the insulating layer 30 is roughened, the wiring layer 70 is formed on the surface 30a of the insulating layer 30 by wet plating.

For example, electroless plating and electrolytic plating can be combined to form a wiring layer 70 including a wiring pattern having a desired pattern by a semi-additive method.

Since the surface roughness of the surface 30a of the obtained insulating layer 30 can be made lower and contributes to the miniaturization and high density of the wiring, the step (F-1) is performed as the step (F). Is preferable.

The circuit board 10 is manufactured by the above steps. Although an example in which only one insulating layer 30 is formed has been described here, one or more so-called build-up layers including a further insulating layer and a wiring layer provided on the insulating layer may be further formed.

<Resin sheet with plastic film support>
The resin sheet 60 with a plastic film support used in the manufacturing method of the present invention will be described.

The resin sheet 60 with a plastic film support used in the production method of the present invention includes a plastic film support 50 and a resin composition layer 30X to be bonded to the plastic film support 50. These will be described below.

(Plastic film support)
Examples of the material of the plastic film support 50 include polyesters such as polyethylene terephthalate (referred to as “PET”) and polyethylene naphthalate (referred to as “PEN”), polycarbonate (referred to as “PC”), and polymethylmethacrylate (“PET”). Examples thereof include acrylics such as "PMMA"), cyclic polyolefins, triacetyl cellulose (referred to as "TAC"), polyether sulfide (referred to as "PES"), polyether ketones, and polyimides. Among them, PET, PEN and polyimide are preferable, and PET and PEN are more preferable. In one preferred embodiment, the plastic film support 50 is a PET film support or a PEN film support.

When manufacturing the circuit board 10 of the present invention, it is preferable to irradiate a laser from above the plastic film support 50 side to form a small-diameter via hole 40 in the insulating layer 30. From the viewpoint of smoothly forming the via hole 40 by irradiating the laser, it is preferable that the plastic film support 50 can absorb the laser energy. For example, since the PEN film support has ultraviolet (UV) absorption, it can be suitably used as the plastic film support 50 for forming the via hole 40 by UV irradiation.

Laser energy absorption may be imparted or increased by incorporating a laser energy absorbing component in the plastic film support 50. The laser energy absorbing component is not particularly limited as long as it can absorb the laser used for forming the via hole 40, and examples thereof include carbon powder, metal compound powder, metal powder, and black dye. The laser energy absorbing component may be used alone or in combination of two or more.

Examples of the carbon powder include carbon black powders such as furnace black, channel black, acetylene black, thermal black and anthracene black, graphite powders, and powders of mixtures thereof. Examples of the metal compound powder include titanias such as titanium oxide, magnesia such as magnesium oxide, iron oxides such as iron oxide, nickel oxides such as nickel oxide, zinc oxides such as manganese dioxide and zinc oxide, and dioxide. Silicon, aluminum oxide, rare earth oxides, cobalt oxides such as cobalt oxide, tin oxides such as tin oxide, tungsten oxides such as tungsten oxide, silicon carbide, tungsten carbide, boron nitride, silicon nitride, titanium nitride, aluminum nitride , Barium sulfate, rare earth acid sulfide, and powders of mixtures thereof. Metal powders include, for example, silver, aluminum, bismuth, cobalt, copper, iron, magnesium, manganese, molybdenum, nickel, palladium, antimony, silicon, tin, titanium, vanadium, tungsten, zinc, and alloys or mixtures thereof. Examples include powder. Examples of black dyes include azo (monoazo, disazo, etc.) dyes, azo-methine dyes, anthraquinone dyes, quinoline dyes, ketoneimine dyes, fluorone dyes, nitro dyes, xanthene dyes, acenaphthene dyes, quinophthalone dyes, aminoketone dyes, and methine dyes. , Perylene dye, coumarin dye, perinone dye, triphenyl dye, triallylmethane dye, phthalocyanine dye, incrophenol dye, azine dye, and mixtures thereof. As the black dye, it is preferable to use a black dye that is soluble in a solvent in order to improve dispersibility. Among them, as the laser energy absorbing component, carbon powder is preferable, and carbon black is particularly preferable, from the viewpoint of conversion efficiency of laser energy into heat, versatility, and the like. The upper limit of the average particle size of the laser energy absorbing component is preferably 20 μm or less, more preferably 10 μm or less, from the viewpoint of efficiently absorbing the laser energy. From the viewpoint of dispersibility, the lower limit of the average particle size is preferably 0.001 μm or more, and more preferably 0.002 μm. The "average particle size" referred to here can be measured by a particle size distribution measuring device or the BET method. The BET method is a method in which molecules having a known adsorption area are adsorbed on the surface of powder particles at the temperature of liquid nitrogen, and the specific surface area of the sample is obtained from the amount. Further, the average particle size can be calculated from the specific surface area obtained by the BET method.

The content of the laser energy absorbing component is preferably 0.01% by mass or more from the viewpoint of smoothly forming the via hole 40 when all the components constituting the plastic film support 50 are 100% by mass. It is preferably 0.03% by mass, more preferably 0.05% by mass or more. The upper limit of the content is preferably 40% by mass or less, more preferably 20% by mass or less, still more preferably 10% by mass or less, from the viewpoint of obtaining the plastic film support 50 having good flexibility. Is. The laser energy absorbing component may be contained in the release layer described later.

Commercially available products of the plastic film support 50 include, for example, "Lumirror R56", "Lumirror R80", "Lumirror T6AM" (PET film) manufactured by Toray Co., Ltd., and "G2LA" manufactured by Teijin DuPont Film Co., Ltd. ( PET film), "Theonex Q83" (PEN film), "UPIREX-S" (polyimide film) manufactured by Ube Kosan Co., Ltd., "Apical AH", "Apical NPI" (polyimide film) manufactured by Kaneka Co., Ltd., etc. Can be mentioned.

The surface of the plastic film support 50 to be joined to the resin composition layer 30X may be matted or corona-treated.

Since it is easy to adjust the adhesion strength between the insulating layer 30 and the plastic film support 50 within a desired range in the step (B), the plastic film support 50 is released from the surface to be bonded to the resin composition layer 30X. A plastic film support 50 with a release layer having a mold layer is suitable. Examples of the release agent that can be used for the release layer include non-silicone release agents such as alkyd resin, melamine resin, olefin resin, and urethane resin, and silicone release agents. The release agent may be used alone or in combination of two or more. Above all, when the resin sheet 60 with the plastic film support is produced, it exhibits high wettability to the resin varnish and the contact state with the resin composition layer 30X tends to be uniform over the entire surface. Therefore, the release layer is made of non-silicone. A release layer containing a release agent is preferable, and a release layer containing an alkyd resin and / or an olefin resin is more preferable.

The release agent is a so-called light release type release agent having a low release strength, a so-called heavy release type release agent having a high release strength, and a light release type release agent, depending on the type of its constituent components. It can be classified as a so-called medium release type release agent, which shows an intermediate release strength between the release agent and the heavy release type release agent, but it is heavy because it is easy to adjust the adhesion strength to a desired range in the step (B). A release type release agent is preferable. Although it depends on the composition of the resin composition layer 30X for forming the insulating layer 30, the laminating conditions of the step (A), the thermal curing conditions of the step (B), etc., the initial adhesion strength of the mold release agent is high. Is preferably 100 (mN / 20 mm) or more, more preferably 300 (mN / 20 mm) or more, still more preferably 500 (mN / 20 mm) or more, 700 (mN / 20 mm) or more, 800 (mN). A mold release agent having a size of / 20 mm) or more, 900 (mN / 20 mm) or more, or 1000 (mN / 20 mm) or more can be used. The upper limit of the initial adhesion strength is not particularly limited, but is usually 8000 (mN / 20 mm) or less and 7500 (mN / 20 mm) or less from the viewpoint of smoothly peeling off the plastic film support 50 in the step (E). And so on. The initial adhesion strength is as follows: Acrylic adhesive tape (“31B” manufactured by Nitto Denko Corporation) is attached to the surface that has been released with a mold release agent using a 2 kg roller, left for 30 minutes, and then one end of the acrylic adhesive tape. It can be obtained by measuring the load (mN / 20 mm) when the film is peeled off, grasped with a gripper, and peeled off under the conditions of a speed of 30 cm / min and a peeling angle of 180 ° at room temperature. The measurement may be carried out using, for example, a tensile tester such as "AC-50C-SL" manufactured by TSE Co., Ltd.

Commercially available release agents include, for example, "X" (silicone-containing alkyd resin-based mold release agent; 490 mN / 20 mm) and "SK-1" (silicone-containing alkyd resin-based mold release agent) manufactured by Lintec Co., Ltd .; 1250mN / 20mm), "AL-5" (non-silicone / alkyd resin release agent; 1480mN / 20mm), "6050" (non-silicone / alkyd resin release agent; 2400mN / 20mm), "6051" (non-silicone) Silicone / alkyd resin-based mold release agent; 2800 mN / 20 mm), "6052" (non-silicone / alkyd resin-based mold release agent; 4000 mN / 20 mm) and the like (the initial adhesion strength value is shown in parentheses). Commercially available release agents include "AL-7" (non-silicone / alkyd resin-based release agent; heavy release type) manufactured by Lintec Co., Ltd. and "NSP-4" manufactured by Fujimori Kogyo Co., Ltd. ( Non-silicone / alkyd resin-based mold release agent; heavy release type) and the like.

The thickness of the plastic film support 50 is not particularly limited, but is preferably in the range of 10 μm to 100 μm, and more preferably in the range of 15 μm to 75 μm. In particular, from the viewpoint of facilitating the formation of small diameter vias, the range is more preferably in the range of 20 μm to 50 μm. When the plastic film support 50 is a plastic film support 50 with a release layer, the thickness of the entire plastic film support 50 with a release layer is preferably in the above range.

(Resin composition layer)
The resin composition used for the resin composition layer 30X is not particularly limited as long as the cured product has sufficient hardness and insulating properties and provides a desired adhesion strength with the plastic film support 50. As the resin composition, for example, a resin composition containing an epoxy resin, a curing agent and an inorganic filler can be used. The resin composition used for the resin composition layer 30X may further contain additives such as a thermoplastic resin, a curing accelerator, a flame retardant and an organic filler, if necessary. Hereinafter, the components of the resin composition will be described.

-Epoxy resin-
Examples of the epoxy resin include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, bisphenol AF type epoxy resin, dicyclopentadiene type epoxy resin, trisphenol type epoxy resin, and naphthol novolac type epoxy resin. Phenol novolac type epoxy resin, tert-butyl-catechol type epoxy resin, naphthalene type epoxy resin, naphthol type epoxy resin, anthracene type epoxy resin, glycidylamine type epoxy resin, glycidyl ester type epoxy resin, cresol novolac type epoxy resin, biphenyl type Epoxy resin, linear aliphatic epoxy resin, epoxy resin having a butadiene structure, alicyclic epoxy resin, heterocyclic epoxy resin, spiro ring-containing epoxy resin, cyclohexanedimethanol type epoxy resin, naphthylene ether type epoxy resin and tri Examples thereof include methylol type epoxy resins. The exemplified epoxy resin may be used alone or in combination of two or more.

The epoxy resin preferably contains an epoxy resin having two or more epoxy groups in one molecule. When the non-volatile component of the epoxy resin is 100% by mass, at least 50% by mass or more is preferably an epoxy resin having two or more epoxy groups in one molecule. Among them, an epoxy resin having two or more epoxy groups in one molecule and being liquid at a temperature of 20 ° C. (hereinafter referred to as "liquid epoxy resin") and three or more epoxy groups in one molecule. , It is preferable to include an epoxy resin which is solid at a temperature of 20 ° C. (hereinafter referred to as "solid epoxy resin"). By using a liquid epoxy resin and a solid epoxy resin in combination as the epoxy resin, a resin composition having excellent flexibility can be obtained. In addition, the breaking strength of the cured product of the resin composition is also improved.

As the liquid epoxy resin, bisphenol A type epoxy resin, bisphenol F type epoxy resin, naphthalene type epoxy resin, glycidyl ester type epoxy resin, phenol novolac type epoxy resin, and epoxy resin having a butadiene structure are preferable, and bisphenol A type epoxy resin. , Bisphenol F type epoxy resin, and naphthalene type epoxy resin are more preferable. Specific examples of the liquid epoxy resin include "HP4032", "HP4032H", "HP4032D", "HP4032SS" (naphthalene type epoxy resin) manufactured by DIC Co., Ltd., and "jER828EL" (bisphenol A) manufactured by Mitsubishi Chemical Corporation. Type epoxy resin), "jER807" (bisphenol F type epoxy resin), "jER152" (phenol novolac type epoxy resin), "ZX1059" (bisphenol A type epoxy resin and bisphenol F type epoxy resin) manufactured by Nippon Steel & Sumitomo Metal Corporation (Mixed product with), "EX-721" (glycidyl ester type epoxy resin) manufactured by Nagase ChemteX Corporation, and "PB-3600" (epoxy resin having a butadiene structure) manufactured by Daicel Chemical Industry Co., Ltd. Be done. These may be used individually by 1 type, and may be used in combination of 2 or more type.

Examples of the solid epoxy resin include naphthalene type tetrafunctional epoxy resin, cresol novolac type epoxy resin, dicyclopentadiene type epoxy resin, trisphenol type epoxy resin, naphthol type epoxy resin, biphenyl type epoxy resin, and naphthylene ether type epoxy resin. Anthracene type epoxy resin is preferable, and naphthalene type tetrafunctional epoxy resin, naphthol type epoxy resin, and biphenyl type epoxy resin are more preferable. Specific examples of the solid epoxy resin include "HP-4700", "HP-4710" (naphthalene type tetrafunctional epoxy resin), "N-690" (cresol novolac type epoxy resin), and "Kresornovolak type epoxy resin" manufactured by DIC Co., Ltd. N-695 "(cresol novolac type epoxy resin)," HP-7200 "(dicyclopentadiene type epoxy resin)," EXA7311 "," EXA7311-G3 "," EXA7311-G4 "," EXA7311-G4S "," HP6000 (Naftylene ether type epoxy resin), "EPPN-502H" (Trisphenol type epoxy resin) manufactured by Nippon Kayaku Co., Ltd., "NC7000L" (naphthol novolac type epoxy resin), "NC3000H", "NC3000", "NC3000L", "NC3100" (biphenyl type epoxy resin), "ESN475V" (naphthol type epoxy resin) manufactured by Nippon Steel & Sumitomo Metal Corporation, "ESN485V" (naphthol novolac type epoxy resin), manufactured by Mitsubishi Chemical Co., Ltd. "YX4000H", "YL6121" (biphenyl type epoxy resin), "YX4000HK" (bixilenol type epoxy resin), "YX8800" (anthracene type epoxy resin), "PG-100" manufactured by Osaka Gas Chemical Co., Ltd., " Examples thereof include "CG-500" and "YL7800" (fluorene type epoxy resin) manufactured by Mitsubishi Chemical Corporation.

When a liquid epoxy resin and a solid epoxy resin are used in combination as the epoxy resin, their quantity ratio (liquid epoxy resin: solid epoxy resin) is in the range of 1: 0.1 to 1: 6 in terms of mass ratio. It is preferable to do so. By setting the amount ratio of the liquid epoxy resin to the solid epoxy resin in such a range, i) appropriate adhesiveness is obtained when used in the form of a resin sheet with a plastic film support, ii) a plastic film support. When used in the form of an epoxy sheet, sufficient flexibility is obtained, handleability is improved, and iii) a cured product having sufficient breaking strength can be obtained. From the viewpoint of the effects of i) to iii) above, the quantitative ratio of the liquid epoxy resin to the solid epoxy resin (liquid epoxy resin: solid epoxy resin) is 1: 0.3 to 1: 5 in terms of mass ratio. It is more preferably in the range, further preferably in the range of 1: 0.6 to 1: 4.5.

The content of the epoxy resin in the resin composition is preferably 3% by mass to 40% by mass, more preferably 5% by mass to 35% by mass, and further preferably 10% by mass to 30% by mass.

In the present specification, the content of each component in the resin composition is a value when the non-volatile component in the resin composition is 100% by mass, unless otherwise specified.

The weight average molecular weight of the epoxy resin is preferably 100 to 5000, more preferably 250 to 3000, and even more preferably 400 to 1500. Here, the weight average molecular weight of the epoxy resin is a polystyrene-equivalent weight average molecular weight measured by a gel permeation chromatography (GPC) method.

The epoxy equivalent of the epoxy resin is preferably 50 to 3000, more preferably 80 to 2000, and even more preferably 110 to 1000. Within this range, the crosslink density of the cured product becomes sufficient, and an insulating layer having a small surface roughness can be provided. The epoxy equivalent can be measured according to the method specified in JIS K7236, and is the mass of the resin containing 1 equivalent of the epoxy group.

-Hardener-
The curing agent is not particularly limited as long as it has a function of curing the epoxy resin, and is, for example, a phenol-based curing agent, a naphthol-based curing agent, an active ester-based curing agent, a benzoxazine-based curing agent, a cyanate ester-based curing agent, and a carbodiimide. Examples include system curing agents. The curing agent may be used alone or in combination of two or more.

As the phenol-based curing agent and the naphthol-based curing agent, a phenol-based curing agent having a novolak structure or a naphthol-based curing agent having a novolak structure is preferable from the viewpoint of heat resistance and water resistance. Further, from the viewpoint of adhesion strength with the conductor layer, a nitrogen-containing phenol-based curing agent or a nitrogen-containing naphthol-based curing agent is preferable, and a triazine skeleton-containing phenol-based curing agent or a triazine skeleton-containing naphthol-based curing agent is more preferable. Of these, a triazine skeleton-containing phenol novolac resin is preferable from the viewpoint of highly satisfying heat resistance, water resistance, and adhesion strength with the conductor layer. These may be used individually by 1 type, and may be used in combination of 2 or more type.

Specific examples of the phenol-based curing agent and the naphthol-based curing agent include, for example, "MEH-7700", "MEH-7810", "MEH-7851" manufactured by Meiwa Kasei Co., Ltd., and Nippon Kayaku Co., Ltd. "NHN", "CBN", "GPH", "SN-170", "SN-180", "SN-190", "SN-475", "SN-485", "SN-485" manufactured by Toto Kasei Co., Ltd. Examples thereof include "SN-495", "SN-375", "SN-395", "LA-7052", "LA-7054", "LA-3018", "LA-1356" manufactured by DIC Co., Ltd. ..

An active ester-based curing agent is also preferable from the viewpoint of increasing the adhesion strength with the conductor layer 24. The active ester-based curing agent is not particularly limited, but generally contains an ester group having high reactive activity such as phenol esters, thiophenol esters, N-hydroxyamine esters, and esters of heterocyclic hydroxy compounds in one molecule. A compound having two or more esters is preferably used. The active ester-based curing agent is preferably obtained by a condensation reaction between a carboxylic acid compound and / or a thiocarboxylic acid compound and a hydroxy compound and / or a thiol compound. In particular, from the viewpoint of improving heat resistance, an active ester-based curing agent obtained from a carboxylic acid compound and a hydroxy compound is preferable, and an active ester-based curing agent obtained from a carboxylic acid compound and a phenol compound and / or a naphthol compound is more preferable. Examples of the carboxylic acid compound include benzoic acid, acetic acid, succinic acid, maleic acid, itaconic acid, phthalic acid, isophthalic acid, terephthalic acid, pyromellitic acid and the like. Examples of the phenol compound or naphthol compound include hydroquinone, resorcin, bisphenol A, bisphenol F, bisphenol S, phenolphthaline, methylated bisphenol A, methylated bisphenol F, methylated bisphenol S, phenol, o-cresol, and m-cresol. , P-cresol, catechol, α-naphthol, β-naphthol, 1,5-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 2,6-dihydroxynaphthalene, dihydroxybenzophenone, trihydroxybenzophenone, tetrahydroxybenzophenone, fluoroglusin, benzene Examples thereof include triol, dicyclopentadiene type diphenol compound, and phenol novolac. Here, the "dicyclopentadiene-type diphenol compound" refers to a diphenol compound obtained by condensing two phenol molecules with one dicyclopentadiene molecule.

Examples of the active ester-based curing agent include an active ester compound containing a dicyclopentadiene-type diphenol structure, an active ester compound containing a naphthalene structure, an active ester compound containing an acetylated product of phenol novolac, and an active ester compound containing a benzoyl product of phenol novolac. Of these, an active ester compound containing a naphthalene structure and an active ester compound containing a dicyclopentadiene-type diphenol structure are more preferable. These may be used individually by 1 type, and may be used in combination of 2 or more type. The "dicyclopentadiene-type diphenol structure" represents a divalent structural unit composed of phenylene-dicyclopentalene-phenylene.

Commercially available products of active ester-based curing agents include "EXB9451", "EXB9460", "EXB9460S", "HPC8000-65T" (manufactured by DIC Co., Ltd.) as active ester compounds containing a dicyclopentadiene type diphenol structure. "EXB9416-70BK" (manufactured by DIC Co., Ltd.) as an active ester compound containing a naphthalene structure, "DC808" (manufactured by Mitsubishi Chemical Co., Ltd.) as an active ester compound containing an acetylated product of phenol novolac, and a benzoylated product of phenol novolac. Examples of the active ester compound contained include "YLH1026" (manufactured by Mitsubishi Chemical Corporation).

Specific examples of the benzoxazine-based curing agent include "HFB2006M" manufactured by Showa Polymer Co., Ltd., "Pd" and "FA" manufactured by Shikoku Chemicals Corporation.

The cyanate ester-based curing agent is not particularly limited, and for example, a novolak type (phenol novolac type, alkylphenol novolak type, etc.) cyanate ester-based curing agent, a dicyclopentadiene type cyanate ester-based curing agent, a bisphenol type (bisphenol A type, etc.) Examples thereof include bisphenol F type, bisphenol S type, etc.) cyanate ester-based curing agents, and prepolymers in which these are partially triazined. Specific examples include bisphenol A disyanate (BADCy, also referred to as 2,2-bis (4-cyanate phenyl) propane), polyphenol cyanate (oligo (3-methylene-1,5-phenylene cyanate)), 4, 4'-Methylenebis (2,6-Dimethylphenylcyanate), 4,4'-Etilidendidiphenyldisianate, Hexafluorobisphenol A-Cyanate, 1,1-bis (4-Cyanatephenyl) methane, Bis (4-Cyanate-3) , 5-Dimethylphenyl) methane, 1,3-bis (4-cyanatephenyl-1- (methylethylidene)) benzene, bis (4-cyanatephenyl) thioether, and bis (4-cyanatephenyl) ether. Examples thereof include a polyfunctional cyanate resin derived from cyanate resin, phenol novolac, cresol novolak and the like, and a prepolymer in which these cyanate resins are partially triazined. Commercially available cyanate ester-based curing agents include "PT30" and "PT60" (both phenol novolac type polyfunctional cyanate ester resins) manufactured by Ronza, and "BA230" (part or all of bisphenol A disicanate are triazined. Prepolymer that has become a trimer), "Primaset (registered trademark) BADBy" and the like.

Specific examples of the carbodiimide-based curing agent include "V-03" and "V-07" manufactured by Nisshinbo Chemical Co., Ltd.

The amount ratio of the epoxy resin to the curing agent is the ratio of [total number of epoxy groups in the epoxy resin]: [total number of reactive groups in the curing agent] from the viewpoint of improving the mechanical strength and water resistance of the obtained insulating layer. The range of 1: 0.2 to 1: 2 is preferable, the range of 1: 0.3 to 1: 1.5 is more preferable, and the range of 1: 0.4 to 1: 1 is further preferable. Here, the reactive group of the curing agent is an active hydroxyl group, an active ester group, or the like, and differs depending on the type of the curing agent. The total number of epoxy groups in the epoxy resin is the total number of all epoxy resins obtained by dividing the mass of the non-volatile components of each epoxy resin by the epoxy equivalent, and what is the total number of reactive groups in the curing agent? , The value obtained by dividing the mass of the non-volatile component of each curing agent by the reaction group equivalent is the total value for all the curing agents.

-Inorganic filler-
The material of the inorganic filler is not particularly limited, but for example, silica, alumina, glass, cordierite, silicon oxide, barium sulfate, barium carbonate, talc, clay, mica powder, zinc oxide, hydrotalcite, boehmite, etc. Aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, magnesium oxide, boron nitride, aluminum nitride, manganese nitride, aluminum borate, strontium carbonate, zirconite oxide, barium titanate, lead zirconate titanate, strontium titanate, Examples thereof include calcium titanate, magnesium titanate, bismuth titanate, titanium oxide, barium zirconate, calcium zirconate, zirconate titer, zirconate titnate and the like. Among these, silica such as amorphous silica, fused silica, crystalline silica, synthetic silica, and hollow silica are particularly suitable. Further, as silica, spherical silica is preferable. The inorganic filler may be used alone or in combination of two or more. Examples of commercially available spherical fused silica include "SO-C3", "SO-C2", "SO-C1", "YA100C", "YA050C", and "YA010C" manufactured by Admatex Co., Ltd.

The average particle size of the inorganic filler is preferably 3 μm or less, more preferably 1 μm or less, and 0.7 μm or less, from the viewpoint of obtaining an insulating layer capable of forming a fine wiring pattern on the inorganic filler. More preferably, it is 0.5 μm or less, 0.4 μm or less, or 0.3 μm or less. The lower limit of the average particle size of the inorganic filler is 0.01 μm or more from the viewpoint of obtaining a resin varnish having an appropriate viscosity and good handleability when forming a resin varnish using the resin composition. It is more preferably 0.03 μm or more, further preferably 0.05 μm or more, further preferably 0.07 μm or more, and particularly preferably 0.1 μm or more. The average particle size of the inorganic filler can be measured by a laser diffraction / scattering method based on the Mie scattering theory. Specifically, it can be measured by creating a particle size distribution of the inorganic filler on a volume basis with a laser diffraction type particle size distribution measuring device and using the median diameter as the average particle size. As the measurement sample, an inorganic filler dispersed in water by ultrasonic waves can be preferably used. As the laser diffraction type particle size distribution measuring device, "LA-500", "LA-750", "LA-950", etc. manufactured by HORIBA, Ltd. can be used.

As the inorganic filler used in the production method of the present embodiment, it is preferable to use an inorganic filler from which coarse particles have been removed by classification. In one embodiment, it is preferable to use an inorganic filler from which particles having a particle size of 10 μm or more have been removed by classification, and more preferably to use an inorganic filler from which particles having a particle size of 5 μm or more have been removed by classification. It is more preferable to use an inorganic filler from which particles having a particle size of 3 μm or more have been removed by classification.

The average particle size of the inorganic filler is preferably 0.01 μm to 3 μm, more preferably 0.01 μm to 0.4 μm.

The inorganic filler is preferably surface-treated with a surface treatment agent from the viewpoint of improving dispersibility and moisture resistance. Examples of the surface treatment agent include aminosilane-based coupling agents, epoxysilane-based coupling agents, mercaptosilane-based coupling agents, silane-based coupling agents, organosilazane compounds, and titanate-based coupling agents. The surface treatment agent may be used alone or in combination of two or more. Commercially available surface treatment agents include, for example, "KBM403" (3-glycidoxypropyltrimethoxysilane) manufactured by Shin-Etsu Chemical Co., Ltd. and "KBM803" (3-mercaptopropyltrimethoxy) manufactured by Shin-Etsu Chemical Co., Ltd. Silane), "KBE903" (3-aminopropyltriethoxysilane) manufactured by Shin-Etsu Chemical Co., Ltd., "KBM573" (N-phenyl-3-aminopropyltrimethoxysilane) manufactured by Shin-Etsu Chemical Co., Ltd., Shin-Etsu Chemical Co., Ltd. Examples thereof include "SZ-31" (hexamethyldisilazane) manufactured by Co., Ltd.

After the surface treatment of the inorganic filler, the amount of carbon per unit surface area bonded to the surface of the inorganic filler is preferably 0.05 mg / m ² or more, more preferably 0.08 mg / m ² or more. , more preferably not more 0.11 mg / ^{m 2} or more, even more preferably at 0.14 mg / ^{m 2} or more, particularly preferably 0.17 mg / ^{m 2} or more, 0.20 mg / ^{m 2} or more, 0.23 mg / M ² or more, or 0.26 mg / m ² or more. The upper limit of carbon content is preferably not more than 1.00 mg / ^{m 2,} more preferably not more than 0.75 mg / ^{m 2,} still more preferably 0.70 mg / ^{m 2} or less, even more preferably 0. 65 mg / ^{m 2} or less, 0.60 mg / ^{m 2} or less, 0.55 mg / ^{m 2} or less, 0.50 mg / ^{m 2} or less.

The amount of carbon per unit area bonded to the surface of the inorganic filler can be calculated by the following procedure. A sufficient amount of methyl ethyl ketone (MEK) as a solvent is added to the surface-treated inorganic filler and ultrasonically cleaned. After removing the supernatant and drying the obtained non-volatile component, the amount of carbon bonded to the surface of the inorganic filler is measured using a carbon analyzer. The amount of carbon per unit surface area bonded to the inorganic filler is calculated by dividing the obtained amount of carbon by the specific surface area of the inorganic filler. Examples of the carbon analyzer include "EMIA-320V" manufactured by HORIBA, Ltd.

The content of the inorganic filler in the resin composition is from the viewpoint of reducing the coefficient of thermal expansion of the insulating layer 30 and preventing the occurrence of cracks and circuit distortion due to the difference in thermal expansion between the insulating layer 30 and the conductor layer 24. , 40% by mass or more, more preferably 50% by mass or more, and even more preferably 60% by mass or more. When the insulating layer 30 is formed by using a resin composition having a high content of an inorganic filler, the adhesion strength between the insulating layer 30 and the conductor layer 24 may decrease, but it depends on the method for manufacturing a circuit board of the present invention. For example, even when a resin composition having a high content of an inorganic filler is used, sufficient adhesion strength between the insulating layer 30 and the conductor layer 24 can be realized. In the method for manufacturing a circuit board of the present invention, the content of the inorganic filler in the resin composition can be further increased without lowering the adhesion strength between the insulating layer 30 and the conductor layer 24. For example, the content of the inorganic filler in the resin composition may be increased to 62% by mass or more, 64% by mass or more, 66% by mass or more, 68% by mass or more, or 70% by mass or more.

From the viewpoint of the mechanical strength of the insulating layer 30, the upper limit of the content of the inorganic filler is preferably 95% by mass or less, more preferably 90% by mass or less, and further preferably 85% by mass or less. preferable.

In one embodiment, the resin composition used for the resin composition layer 30X comprises the above-mentioned epoxy resin, curing agent and inorganic filler. Among them, the resin composition is a mixture of a liquid epoxy resin and a solid epoxy resin as an epoxy resin (the mass ratio of the liquid epoxy resin: the solid epoxy resin is preferably 1: 0.1 to 1: 6, and more preferably 1. : 0.3 to 1: 5, more preferably 1: 0.6 to 1: 4.5) as a curing agent, a phenol-based curing agent, a naphthol-based curing agent, an active ester-based curing agent, and a cyanate ester-based curing agent. It is preferable that one or more selected from the group consisting of is containing silica as an inorganic filler. Regarding the resin composition layer 30X containing such a specific component in combination, the preferable contents of the epoxy resin, the curing agent, and the inorganic filler are as described above, and among them, the content of the epoxy resin is 5% by mass. The content of the inorganic filler is preferably 40% by mass to 95% by mass, the content of the epoxy resin is 10% by mass to 30% by mass, and the content of the inorganic filler is 50% by mass to 50% by mass. More preferably, it is 90% by mass. Regarding the content of the curing agent, it is preferable that the ratio of the total number of epoxy groups of the epoxy resin to the total number of reactive groups of the curing agent is 1: 0.2 to 1: 2. It is more preferable to contain the content so as to be 1: 0.3 to 1: 1.5, and further preferably to contain the content so as to be 1: 0.4 to 1: 1.

The resin composition used for forming the resin composition layer 30X may further contain a thermoplastic resin, a curing accelerator, a flame retardant, an organic filler, and the like, if necessary. Hereinafter, these components will be described.

-Thermoplastic resin-
Examples of the thermoplastic resin include phenoxy resin, polyvinyl acetal resin, polyolefin resin, polybutadiene resin, polyimide resin, polyamideimide resin, polyetherimide resin, polysulfone resin, polyethersulfone resin, polyphenylene ether resin, polycarbonate resin, and polyether. Examples thereof include ether ketone resin and polyester resin. The thermoplastic resin may be used alone or in combination of two or more.

The polystyrene-equivalent weight average molecular weight of the thermoplastic resin is preferably in the range of 8000 to 70000, more preferably in the range of 1000 to 60000, and even more preferably in the range of 20000 to 60000. The polystyrene-equivalent weight average molecular weight of the thermoplastic resin is measured by gel permeation chromatography (GPC). Specifically, the polystyrene-equivalent weight average molecular weight of the thermoplastic resin is determined by using LC-9A / RID-6A manufactured by Shimadzu Corporation as a measuring device and Shodex K-800P / K- by Showa Denko Corporation as a column. 804L / K-804L can be measured using chloroform or the like as a mobile phase and a column temperature of 40 ° C., and can be calculated using a standard polystyrene calibration curve.

Examples of the phenoxy resin include bisphenol A skeleton, bisphenol F skeleton, bisphenol S skeleton, bisphenol acetphenone skeleton, novolak skeleton, biphenyl skeleton, fluorene skeleton, dicyclopentadiene skeleton, norbornene skeleton, naphthalene skeleton, anthracene skeleton, adamantan skeleton, and terpen. Examples thereof include a phenoxy resin having one or more skeletons selected from the group consisting of a skeleton and a trimethylcyclohexane skeleton. The terminal of the phenoxy resin may be any functional group such as a phenolic hydroxyl group or an epoxy group. The phenoxy resin may be used alone or in combination of two or more. Specific examples of the phenoxy resin include "1256" and "4250" (both bisphenol A skeleton-containing phenoxy resin), "YX8100" (bisphenol S skeleton-containing phenoxy resin), and "YX6954" manufactured by Mitsubishi Chemical Corporation. Bisphenol acetophenone skeleton-containing phenoxy resin), and other products such as "FX280" and "FX293" manufactured by Toto Kasei Co., Ltd., "YX7553", "YX7553BH30", "YL6794" and "YL6794" manufactured by Mitsubishi Chemical Corporation. Examples thereof include "YL7213", "YL7290" and "YL7482".

Specific examples of the polyvinyl acetal resin include Electrified Butyral 4000-2, 5000-A, 6000-C, 6000-EP manufactured by Denki Kagaku Kogyo Co., Ltd., Eslek BH series and BX series manufactured by Sekisui Chemical Co., Ltd. Examples include the KS series, BL series, and BM series.

Specific examples of the polyimide resin include "Ricacoat SN20" and "Ricacoat PN20" manufactured by New Japan Chemical Co., Ltd. As a specific example of the polyimide resin, a linear polyimide obtained by reacting a bifunctional hydroxyl group-terminated polybutadiene, a diisocyanate compound and a tetrabasic acid anhydride (for example, the linear polyimide described in JP-A-2006-37083). , Polysiloxane skeleton-containing polyimide (polysiloxane skeleton-containing polyimide described in JP-A-2002-12667 and JP-A-2000-319386) and the like.

Specific examples of the polyamide-imide resin include "Vilomax HR11NN" and "Vilomax HR16NN" manufactured by Toyobo Co., Ltd. Specific examples of the polyamide-imide resin include modified polyamide-imides such as polysiloxane skeleton-containing polyamide-imides “KS9100” and “KS9300” manufactured by Hitachi Chemical Industries, Ltd.

Specific examples of the polyether sulfone resin include "PES5003P" manufactured by Sumitomo Chemical Co., Ltd.

Specific examples of the polysulfone resin include polysulfones "P1700" and "P3500" manufactured by Solvay Advanced Polymers Co., Ltd.

The content of the thermoplastic resin in the resin composition is preferably 0.1% by mass to 20% by mass, more preferably 0.5% by mass to 10% by mass, and further preferably 1% by mass to 5% by mass. It is mass%.

-Curing accelerator-
Examples of the curing accelerator include phosphorus-based curing accelerators, amine-based curing accelerators, imidazole-based curing accelerators, guanidine-based curing accelerators, and the like, and phosphorus-based curing accelerators, amine-based curing accelerators, and imidazole-based curing agents. Curing accelerators are preferred. The curing accelerator may be used alone or in combination of two or more. The content of the curing accelerator is preferably in the range of 0.05% by mass to 3% by mass when the total of the non-volatile components of the epoxy resin and the curing agent is 100% by mass. Examples of the curing accelerator include 4-dimethylaminopyridine (DMAP) and cobalt (III) acetylacetonate (Co (III) -1M) (Tokyo Kasei Co., Ltd.).

-Flame retardant-
Examples of the flame retardant include an organic phosphorus flame retardant, an organic nitrogen-containing phosphorus compound, a nitrogen compound, a silicone flame retardant, and a metal hydroxide. The flame retardant may be used alone or in combination of two or more. The content of the flame retardant in the resin composition is not particularly limited, but is preferably 0.5% by mass to 10% by mass, and more preferably 1% by mass to 9% by mass. Examples of the flame retardant include HCA-HQ (manufactured by Sanko Co., Ltd.).

-Organic filler-
As the organic filler, any organic filler that can be used when forming the insulating layer of the circuit board may be used, and examples thereof include rubber particles, polyamide fine particles, and silicone particles, and rubber particles are preferable.

The rubber particles are not particularly limited as long as they are fine particles of a resin that is insoluble and insoluble in an organic solvent by subjecting a resin exhibiting rubber elasticity to a chemical cross-linking treatment. For example, acrylonitrile butadiene rubber particles, butadiene rubber particles, and the like. Acrylo rubber particles and the like can be mentioned. Specific examples of the rubber particles include XER-91 (manufactured by Nippon Synthetic Rubber Co., Ltd.), Staphyroid AC3355, AC3816, AC3816N, AC3832, AC4030, AC3364, IM101 (manufactured by Aica Kogyo Co., Ltd.), Pararoid. Examples thereof include EXL2655 and EXL2602 (all manufactured by Kureha Chemical Industry Co., Ltd.).

The average particle size of the organic filler is preferably in the range of 0.005 μm to 1 μm, more preferably in the range of 0.2 μm to 0.6 μm. The average particle size of the rubber particles can be measured using a dynamic light scattering method. For example, rubber particles are uniformly dispersed in an appropriate organic solvent by ultrasonic waves, etc., and the particle size distribution of the rubber particles is measured on a mass basis using a concentrated particle size analyzer (“FPAR-1000” manufactured by Otsuka Electronics Co., Ltd.). It can be prepared and measured by using the median diameter as the average particle size. The content of the rubber particles in the resin composition is preferably 1% by mass to 10% by mass, and more preferably 2% by mass to 5% by mass.

-Other ingredients-
The resin composition used for the resin composition layer may contain other components, if necessary. Other components include, for example, organometallic compounds such as organocopper compounds, organozinc compounds and organocobalt compounds, and thickeners, defoamers, leveling agents, adhesion-imparting agents, colorants and curable resins. Examples include resin additives.

In the resin sheet 60 with a plastic film support, the resin composition layer 30X may have a multi-layer structure composed of two or more layers. When the resin composition layer 30X has a multi-layer structure, the total thickness thereof is preferably in the above range.

The resin sheet 60 with a plastic film support can be manufactured by forming the resin composition layer 30X so as to be bonded to the plastic film support 50.

The resin composition layer 30X can be formed on the plastic film support 50 by any conventionally known suitable method. For example, a resin varnish in which a resin composition is dissolved in a solvent is prepared, the resin varnish is applied to the surface of the plastic film support 50 using a coating device such as a die coater, and the coating film is dried to dry the resin composition. Layer 30X can be formed.

Examples of the solvent used for preparing the resin varnish include ketone solvents such as acetone, methyl ethyl ketone and cyclohexanone, acetic acid ester solvents such as ethyl acetate, butyl acetate, cellosolve acetate, propylene glycol monomethyl ether acetate and carbitol acetate, and cellosolve. And carbitol solvents such as butyl carbitol, aromatic hydrocarbon solvents such as toluene and xylene, amide solvents such as dimethylformamide, dimethylacetamide and N-methylpyrrolidone and the like. The solvent may be used alone or in combination of two or more.

The coating film may be dried by a known drying method such as heating or blowing hot air. If a large amount of solvent remains in the resin composition layer 30X, it causes swelling after curing. Therefore, the amount of residual solvent in the resin composition is usually 10% by mass or less, preferably 5% by mass or less. Let me. Although it depends on the boiling point of the organic solvent in the resin varnish, for example, when a resin varnish containing a solvent of 30% by mass to 60% by mass is used, the resin composition is dried at 50 ° C. to 150 ° C. for 3 to 10 minutes. Layer 30X can be formed.

In the resin sheet 60 with the plastic film support, the surface of the resin composition layer 30X that is not bonded to the plastic film support 50 (that is, the surface opposite to the plastic film support 50) is the plastic film support 50. A protective film according to the above can be further laminated. The thickness of the protective film is not particularly limited and may be, for example, 1 μm to 40 μm. By laminating the protective film, it is possible to prevent dust and the like from adhering to the surface of the resin composition layer 30X and scratches. The resin sheet 60 with a plastic film support can be rolled up and stored, and can be used by peeling off the protective film when manufacturing the circuit board 10.

[Semiconductor device]
By using the circuit board 10 manufactured by the manufacturing method of the present invention and mounting a semiconductor chip having a desired function on the circuit board 10, a semiconductor device including the circuit board 10 can be manufactured.

Examples of such semiconductor devices include various semiconductor devices used in electric products (for example, computers, mobile phones, digital cameras, televisions, etc.) and vehicles (for example, motorcycles, automobiles, trains, ships, aircraft, etc.). Can be mentioned.

The present invention will be specifically described with reference to Examples, but the present invention is not limited to these Examples. In the following, "parts" and "%" mean "parts by mass" and "% by mass", respectively, unless otherwise specified.

Hereinafter, Examples 1 to 3 and Comparative Examples 1 to 4 will be described.

[Sample creation and evaluation]
(1) Substrate treatment of wiring board Glass cloth base material epoxy resin laminated board (copper foil thickness 18 μm, substrate thickness 0.3 mm, size) in which a circular conductor pattern (wiring pattern) with a diameter of 150 μm is formed on both sides. Processing (i) "CZ8100" manufactured by MEC Co., Ltd. on both sides of a conductor pattern (wiring board having a conductor pattern (residual copper ratio of about 70%) formed using "R5715ES" manufactured by Panasonic Corporation, 510 mm x 340 mm). A sample (i) obtained by roughening the surface of the conductor pattern after removing it by etching to a thickness of about 0.6 μm, and a process (ii) instead of the process (i) on the surface of the conductor pattern. A sample (ii) obtained by performing a "flat bond" treatment manufactured by Co., Ltd. was prepared.

(Measurement of arithmetic mean roughness (Ra value) on the surface of the conductor layer)
Using a non-contact type surface roughness meter (WYKO NT3300 manufactured by Becoin Sturments), the Ra value was obtained as a numerical value obtained with a measurement range of 121 μm × 92 μm using a VSI contact mode and a 50x lens. The Ra value is a value obtained by obtaining the average value of the measured values of 10 points of each of the sample (i) and the sample (ii). The Ra value of the sample (i) treated with CZ8100 was 270 nm, and the Ra value of the sample (ii) treated with the flat bond was 160 nm. As described above, in this embodiment, the Ra value is made smaller than the Ra value (500 nm to 700 nm) obtained by the conventional treatment (etching having a thickness of about 1 μm to 2 μm).

(2) Laminating Step of Resin Sheet with Plastic Film Support Peel off the protective film of the resin sheet with plastic film support (prepreg with plastic film support) (size 504 mm x 334 mm) produced as shown in the following production example. Then, using a batch type vacuum pressurizing laminator (manufactured by Nichigo Morton Co., Ltd., 2-stage build-up laminator, CVP700), wiring is performed so that the resin composition layer is in contact with the wiring substrate treated in (1) above. It was laminated on both sides of the substrate. This laminating step was carried out by reducing the pressure for 30 seconds to reduce the atmospheric pressure to 13 hPa or less, and then crimping for 30 seconds under the conditions of a temperature of 110 ° C. and a pressure of 0.74 MPa. Next, a heat pressing step was performed for 60 seconds under the conditions of a temperature of 110 ° C. and a pressure of 0.5 MPa.

When the resin sheet with a plastic film support is a prepreg with a plastic film support, after joining the prepreg with the plastic film support to both sides of the wiring substrate, the laminating step is reduced to 13 hPa or less for 30 seconds. It was carried out by crimping for 60 seconds under the conditions of a temperature of 120 ° C. and a pressure of 0.74 MPa. Next, a heat pressing step was performed for 90 seconds under the conditions of a temperature of 120 ° C. and a pressure of 0.5 MPa.

(Measurement and evaluation of adhesion strength (peel strength) between conductor layer and insulating layer)
The peel strength was measured by the following treatments (a) to (c).
(A) Base treatment of copper foil The glossy surface side of 3EC-III (electrolytic copper foil, thickness 35 μm) manufactured by Mitsui Mining & Smelting Co., Ltd. is treated (i) thickened by “CZ8100” manufactured by MEC Co., Ltd. Sample (i) obtained by roughening the surface of the copper foil by etching and removing by 0.6 μm, and treatment (ii) "flat bond" treatment manufactured by MEC Co., Ltd. instead of the treatment (i). A sample (ii) obtained by treating the surface of the copper foil was prepared. The surface roughness of the copper foil was 270 (nm) for the sample (i) treated with CZ8100, and 160 (nm) for the sample (ii) treated with the flat bond. It was.

(B) Lamination of copper foil and formation of insulating layer The plastic film support (PET film) is peeled off from the resin sheet with plastic film support (prepreg with plastic film support) laminated in (2) above, and the above (PET film) is peeled off. A resin composition in which the glossy surface side of the copper foil treated in a) is directed toward the resin composition layer side, and the copper foil is formed on both sides of the wiring substrate under the same conditions as in the laminating step of (2) above. Laminated into layers. The resin composition layer was heat-cured by heat treatment at 120 ° C. for 30 minutes and then at 175 ° C. for 30 minutes to obtain a sample (circuit board) for evaluation as an insulating layer. The obtained circuit board is referred to as "evaluation board A". Further, the laminated copper foil is called a conductor layer.

(C) Measurement of Peeling Strength (Peel Strength) of Conductor Layer The evaluation substrate A obtained in (b) above was cut into small pieces of 150 mm × 30 mm. Make a strip-shaped notch with a width of 10 mm and a length of 100 mm in the copper foil part of a small piece, and peel off one end of the strip-shaped notch in the copper foil to hold the gripper (TSE Co., Ltd., Autocom type). Grasp with a testing machine AC-50C-SL) and measure the load when 35 mm is peeled off perpendicular to the surface of the evaluation substrate A at room temperature at a speed of 50 mm / min using an Instron universal testing machine. Then, the measured value was taken as the peel strength.

A sample having a measured peel strength of 0.15 kgf / cm or more was evaluated as “◯”, and a sample having a measured peel strength of less than 0.15 kgf / cm was evaluated as “x”.

Following the step (2) of laminating the resin sheet with the plastic film support, the following (3) to (7) were carried out to obtain the evaluation substrate B and the evaluation substrate C.

(3) Curing of Resin Composition Layer A wiring board on which a resin sheet with a plastic film support is laminated is placed at 120 ° C. for 30 minutes, then at 175 ° C. for 30 minutes, or at 165 ° C. for 30 minutes (Comparative Examples 1 and 2). After heating, the resin composition layer was thermoset to form an insulating layer.

(4) Formation of Via Hole A laser was irradiated from above on the plastic film support side to form a small diameter via hole in the insulating layer directly above the circular conductor pattern having a diameter of 150 μm inside.

The via hole forming step was carried out under different conditions as shown in the following (A) to (D). Here, the correspondence relationship with Examples 1 to 3 and Comparative Examples 1 to 4 will be described.

Follow the procedure of (A) below for Example 1, Comparative Example 1 and Comparative Example 3, follow the procedure (B) below for Example 2 and Example 4, and follow the procedure (C) below for Example 3 and Comparative Example 4. ), And in Comparative Example 2, a via hole having a small diameter was formed in each insulating layer according to the procedure (D) below.

(A) Using a CO ₂ laser machining machine "605GTWIII (-P)" manufactured by Mitsubishi Electric Corporation, a laser is irradiated from above the plastic film support side to irradiate the insulating layer with a top diameter (diameter) of 30 or 31 μm. Formed a via hole. The laser irradiation conditions were a mask diameter of 1 mm, a pulse width of 16 μs, an energy of 0.20 mJ / shot, a number of shots of 2, and a burst mode (10 kHz).
(B) Using a CO ₂ laser machine "605GTWIII (-P)" manufactured by Mitsubishi Electric Corporation, a laser is irradiated from above the plastic film support side, and a via hole with a top diameter (diameter) of 25 μm is applied to the insulating layer. Was formed. The laser irradiation conditions were a mask diameter of 0.9 mm, a pulse width of 16 μs, an energy of 0.18 mJ / shot, a number of shots of 2, and a burst mode (10 kHz).
(C) Using a CO ₂ laser machine "LC-2k212 / 2C" manufactured by Via Mechanics, Ltd., a laser is irradiated from above the plastic film support side to irradiate the insulating layer with a top diameter (diameter) of 40 or 41 μm. Formed a via hole. The laser irradiation conditions were a mask diameter of 2.5 mm, a pulse width of 4 μs, a power of 0.7 W, a number of shots of 3, and a cycle mode (2 kHz).
(D) Using a CO ₂ laser machine "605GTWIII (-P)" manufactured by Mitsubishi Electric Corporation, a laser is irradiated from above the plastic film support side, and a via hole with a top diameter (diameter) of 29 μm is applied to the insulating layer. Was formed. The laser irradiation conditions were a mask diameter of 0.9 mm, a pulse width of 16 μs, an energy of 0.36 mJ / shot, a number of shots of 2, and a burst mode (10 kHz).

The depth d of the via holes formed in Example 1, Example 2, Example 4, and Comparative Examples 1 to 3 is 15 μm, and the depth d of the via holes formed in Example 3 and Comparative Example 4 is 23 μm. there were.

(5) Desmear Treatment After the via holes were formed, the plastic film support was peeled off, and the circuit board provided with the via holes was subjected to desmear treatment. As the desmear treatment, the following wet desmear treatment was carried out.
Wet desmear treatment:
The circuit board provided with the via hole was placed in a swelling solution (“Swelling Dip Securigant P” manufactured by Atotech Japan Co., Ltd., an aqueous solution of diethylene glycol monobutyl ether and sodium hydroxide) at 60 ° C. for 10 minutes, and then an oxidizing agent solution ( "Concentrate Compact CP" manufactured by Atotech Japan Co., Ltd., an aqueous solution with a potassium permanganate concentration of about 6% and a sodium hydroxide concentration of about 4%) at 80 ° C. for 20 minutes, and finally a neutralizing solution (Atotech Japan Co., Ltd.) ), "Reduction Solution Securigant P", aqueous sulfuric acid solution) at 40 ° C. for 5 minutes, and then dried at 80 ° C. for 15 minutes. The obtained substrate is referred to as "evaluation substrate B".

(6) Confirmation of the shape of the via hole With respect to the evaluation substrate B obtained in (5) above, the opening of the via hole was subjected to a scanning electron microscope (SMI3050SE FIB-SEM composite device manufactured by SII Nanotechnology Co., Ltd.) from the surface. After observing, the central cross section was carved out with a focused ion beam processing observation device (FIB), and from the obtained image, the top diameter (Z) of the via hole, the minimum diameter (Y) of the via hole, and the bottom diameter of the via hole (X). ) And the minimum diameter (Y) from the bottom of the via hole were measured, and the average value of each of the 10 via holes was obtained.

(7) Formation of Conductor Layer In order to form a conductor layer on the surface of the evaluation substrate B, a plating step (copper plating step using a chemical solution manufactured by Atotech Japan Co., Ltd.) including the following steps 1 to 7 is performed to conduct a conductor. A layer was formed.

1. 1. Alkaline cleaning (cleaning of the surface of the insulating layer with via holes and charge adjustment)
Product name: Cleaning was performed at 60 ° C. for 5 minutes using Cleaning Cleaner Security 902 (trade name).
2. 2. Soft etching (cleaning inside the via hole)
Treatment was carried out at 30 ° C. for 1 minute using an aqueous sodium sulfate-acidic peroxodisulfate solution.
3. 3. Predip (Adjustment of charge on the surface of the insulating layer for Pd application)
Pre. Treatment was performed at room temperature for 1 minute using Dip Neoganth B (trade name).
4. Add activator (give Pd to the surface of the insulating layer)
Treatment was performed at 35 ° C. for 5 minutes using Activator Neoganth 834 (trade name).
5. Reduction (Reduction of Pd applied to the insulating layer)
Reducer Neoganth WA (trade name) and Reducer Acceralator 810 mod. Using a mixed solution with (trade name), the treatment was carried out at 30 ° C. for 5 minutes.
6. Electroless copper plating process (Cu is deposited on the surface of the insulating layer (Pd surface))
A mixture of Basic Solution Printganth MSK-DK (trade name), Copper solution Printganth MSK (trade name), Stabilizer Printganth MSK-DK (trade name), and Reducer Cu (trade name) at 35 ° C. Treated for 20 minutes. The thickness of the formed electroless copper plating layer was 1 μm.

7. Electrolytic copper plating step Next, an electrolytic copper plating step was carried out under the condition that the via hole was filled with copper using a chemical solution manufactured by Atotech Japan Co., Ltd. After that, a land pattern having a diameter of 80 μm corresponding to the via hole is formed as a resist pattern for patterning by etching, and a conductor layer having a conductor pattern with a thickness of 15 μm is formed on the surface of the insulating layer using this land pattern. did. Next, the annealing treatment was performed at 190 ° C. for 60 minutes to obtain a circuit board. The obtained circuit board is referred to as "evaluation board C".

<Thermal cycle test>
The evaluation substrate C obtained in (7) above was treated with the small thermal shock device "TSE-11" manufactured by ESPEC CORPORATION for 30 minutes at -55 ° C and 30 minutes at 120 ° C. A thermal cycle test (TCB) was performed in which the process of continuously performing the process b was set as one cycle and this was performed for 1000 cycles. Then, a filled via made of copper filled in the via hole by the above plating step is observed from the surface with a scanning electron microscope (SMI3050SE FIB-SEM composite device manufactured by SII Nanotechnology Co., Ltd.), and then transferred to the FIB. The cross section of the central portion was carved out, and cracks in the insulating layer and the conductor layer and voids in the conductor layer were observed for 10 filled vias, and evaluated according to the following evaluation criteria.
Evaluation criteria:
◯: No cracks or voids were confirmed in all filled vias.
X: Cracks or voids were confirmed for one or more filled vias.

<Preparation Example 1> Preparation of resin varnish 1 6 parts of bisphenol type epoxy resin (epoxy equivalent about 165, "ZX1059" manufactured by Nippon Steel & Sumikin Chemical Co., Ltd., 1: 1 mixture of bisphenol A type and bisphenol F type), bixirenol 10 parts of type epoxy resin (epoxy equivalent about 185, "YX4000HK" manufactured by Mitsubishi Chemical Corporation), 10 parts of biphenyl type epoxy resin (epoxy equivalent about 290, "NC3000H" manufactured by Nippon Kayaku Co., Ltd.), and phenoxy resin ( 10 parts of "YX7553BH30" manufactured by Mitsubishi Chemical Co., Ltd., a methyl ethyl ketone (MEK) solution having a non-volatile component of 30% by mass) was heated and dissolved in 20 parts of a solvenepoxy with stirring. After cooling to room temperature, 10 parts of a triazine skeleton-containing phenol novolac-based curing agent (hydroxyl equivalent 146, "LA-1356" manufactured by DIC Co., Ltd., MEK solution of 60% by mass of non-volatile components), active ester-based curing 10 parts of agent ("HPC8000-65T" manufactured by DIC Co., Ltd., active group equivalent of about 223, toluene solution of 65% by mass of non-volatile component), curing accelerator (4-dimethylaminopyridine (DMAP), 2% by mass of non-volatile component) 4 parts of MEK solution), flame retardant ("HCA-HQ" manufactured by Sanko Co., Ltd., 10- (2,5-dihydroxyphenyl) -10-hydro-9-oxa-10-phosphaphenanthrene-10-oxide , Average particle size 1 μm) 2 parts, rubber particles (“Staphyroid AC3816N” manufactured by Aika Kogyo Co., Ltd., finely pulverized product) 2 parts, aminosilane coupling agent (“KBM573” manufactured by Shinetsu Chemical Industry Co., Ltd.) Small-diameter spherical silica (“SO-C1” manufactured by Admatex Co., Ltd., which has been treated and has particles of 3 μm or more removed by classification, average particle size 0.25 μm, carbon content per unit surface area 0.36 mg / m ² ) 100 parts were mixed and uniformly dispersed with a high-speed rotating mixer to prepare a resin varnish 1. Table 1 shows the compounding components and the compounding amount of the resin varnish 1.

<Preparation Example 2> Preparation of resin varnish 2 6 parts of bisphenol type epoxy resin (epoxy equivalent about 165, "ZX1059" manufactured by Nippon Steel & Sumikin Chemical Co., Ltd., 1: 1 mixture of bisphenol A type and bisphenol F type), naphthalene type Epoxy resin ("HP-4032SS" manufactured by DIC Co., Ltd., epoxy equivalent about 144) 3 parts, bisphenol type epoxy resin (epoxy equivalent about 185, "YX4000HK" manufactured by Mitsubishi Chemical Co., Ltd.) 9 parts, biphenyl type epoxy resin (Epoxy equivalent about 290, "NC3000H" manufactured by Nippon Kayaku Co., Ltd.) and 10 parts of phenoxy resin ("YX7553BH30" manufactured by Mitsubishi Chemical Corporation, methyl ethyl ketone (MEK) solution with 30% by mass of non-volatile component). It was dissolved by heating in 20 parts of solvent naphtha with stirring. After cooling to room temperature, 30 parts of an active ester-based curing agent (“HPC8000-65T” manufactured by DIC Co., Ltd., an active group equivalent of about 223, a toluene solution of 65% by mass of a non-volatile component), and a curing accelerator (4). −Dimethylaminopyridine (DMAP), MEK solution of 2% by mass of non-volatile component), flame retardant (“HCA-HQ” manufactured by Sanko Co., Ltd., 10- (2,5-dihydroxyphenyl) -10-hydro-9 -Oxa-10-phosphaphenanthrene-10-oxide, 2 parts of rubber particles ("Staffyloid AC3816N" manufactured by Aika Kogyo Co., Ltd., finely pulverized product), aminosilane coupling agent Small-diameter spherical silica (“SO-C1” manufactured by Admatex Co., Ltd., which has been surface-treated with (“KBM573” manufactured by Shin-Etsu Chemical Industry Co., Ltd.) and has particles of 3 μm or more removed by classification, and has an average particle size of 0. 25 μm, carbon content per unit surface area 0.36 mg / m ² ) 100 parts were mixed and uniformly dispersed with a high-speed rotating mixer to prepare a resin varnish 2. Table 1 shows the compounding components and the compounding amount of the resin varnish 2.

<Preparation Example 3> Preparation of resin varnish 3 2 parts of bisphenol type epoxy resin (epoxy equivalent about 165, "ZX1059" manufactured by Nippon Steel & Sumikin Chemical Co., Ltd., 1: 1 mixture of bisphenol A type and bisphenol F type), bixirenol 12 parts of type epoxy resin (epoxy equivalent about 185, "YX4000HK" manufactured by Mitsubishi Chemical Corporation), 12 parts of biphenyl type epoxy resin (epoxy equivalent about 290, "NC3000H" manufactured by Nippon Kayaku Co., Ltd.), and phenoxy resin ( 10 parts of "YX7553BH30" manufactured by Mitsubishi Chemical Co., Ltd., a methyl ethyl ketone (MEK) solution having a non-volatile component of 30% by mass) was heated and dissolved in 20 parts of a solvenepoxy with stirring. After cooling to room temperature, 10 parts of an active ester-based curing agent (“HPC8000-65T” manufactured by DIC Co., Ltd., an active group equivalent of about 223, a toluene solution of 65% by mass of non-volatile components), a cyanate ester-based curing agent. (BADCy, Ronza's "Primaset (registered trademark) BADCy") 5 parts, curing accelerator (4-dimethylaminopyridine (DMAP), MEK solution of 2% by mass of non-volatile component), 1 part of curing accelerator (Tokyo Kasei (Tokyo Kasei) Co., Ltd., cobalt (III) acetylacetonate (Co (III) -1M), 2 parts of MEK solution with 1% by mass of non-volatile components), flame retardant ("HCA-HQ" manufactured by Sanko Co., Ltd., 10- (2) , 5-Dihydroxyphenyl) -10-hydro-9-oxa-10-phosphophenanthrene-10-oxide, average particle size 1 μm) 2 parts, rubber particles (Aika Kogyo Co., Ltd. "Staffyloid AC3816N", 2 parts of finely pulverized product), surface-treated with an aminosilane-based coupling agent (“KBM573” manufactured by Shin-Etsu Chemical Industry Co., Ltd.), and small-diameter spherical silica (Admatex Co., Ltd.) from which particles of 3 μm or more have been removed by classification. Ltd. "sO-C1", average particle diameter 0.25 [mu] m, the carbon amount 0.36 mg ^/ m 2 per unit surface area) were mixed 100 parts, was uniformly dispersed in a high-speed rotary mixer to prepare a resin varnish 3. Table 1 shows the compounding components and the compounding amount of the resin varnish 3.

<Production Example 1> Production of Resin Sheet 1 with Plastic Film Support As a plastic film support, a PET film (Toray Industries, Inc.) that has been released with a non-silicone mold release agent (“AL-5” manufactured by Lintec Co., Ltd.) ) "Lumirror T6AM", thickness 38 μm) was prepared. A resin varnish 1 was applied to the release surface of the plastic support with a die coater and dried at 80 ° C. to 110 ° C. (average 100 ° C.) for 3 minutes to form a resin composition layer. The thickness of the resin composition layer was 20 μm. Next, the rough surface side of a polypropylene film (“Alfan MA-411” manufactured by Oji Special Paper Co., Ltd., thickness 15 μm) is attached as a protective film on the surface of the resin composition layer that is not bonded to the plastic film support. Together, a resin sheet 1 with a plastic film support (resin sheet 1) was obtained.

<Production Example 2> Production of Prepreg 2 with Plastic Film Support By the solvent method, 1000 glass cloth (thickness 14 μm) manufactured by Arisawa Seisakusho Co., Ltd. is immersed in the resin varnish 1, impregnated, and heated to volatilize the solvent. , Dry so that the amount of solvent remaining in the prepreg is 0.5% and the thickness is 28 μm, and from both sides, a non-silicone release agent (“AL-5” manufactured by Lintec Co., Ltd.) Release surface of PET film ("Lumilar T6AM" manufactured by Toray Co., Ltd., thickness 38 μm) and polypropylene film ("Alfan MA-411" manufactured by Oji Special Paper Co., Ltd., thickness 15 μm) The rough surface side of the above was bonded to obtain a prepreg 2 with a plastic film support (prepreg 2).

<Production Example 3> Production of Resin Sheet 3 with Plastic Film Support As a plastic film support, a PET film (Toray Industries, Inc.) that has been released with a non-silicone mold release agent (“AL-5” manufactured by Lintec Co., Ltd.) ) "Lumirror T6AM", thickness 38 μm) was prepared. A resin varnish 2 was applied to the release surface of the plastic support with a die coater and dried at 80 ° C. to 110 ° C. (average 100 ° C.) for 3 minutes to form a resin composition layer. The thickness of the resin composition layer was 20 μm. Next, the rough surface side of a polypropylene film (“Alfan MA-411” manufactured by Oji Special Paper Co., Ltd., thickness 15 μm) is attached as a protective film on the surface of the resin composition layer that is not bonded to the plastic film support. In addition, a resin sheet 3 with a plastic film support (resin sheet 3) was obtained.

<Production Example 4> Production of Resin Sheet 4 with Plastic Film Support As a plastic film support, a PET film (Toray Industries, Inc.) that has been released with a non-silicone mold release agent (“AL-5” manufactured by Lintec Co., Ltd.) ) "Lumirror T6AM", thickness 38 μm) was prepared. A resin varnish 3 was applied to the release surface of the plastic support with a die coater and dried at 80 ° C. to 110 ° C. (average 100 ° C.) for 3 minutes to form a resin composition layer. The thickness of the resin composition layer was 20 μm. Next, the rough surface side of a polypropylene film (“Alfan MA-411” manufactured by Oji Special Paper Co., Ltd., thickness 15 μm) is attached as a protective film on the surface of the resin composition layer that is not bonded to the plastic film support. In addition, a resin sheet 4 with a plastic film support (resin sheet 4) was obtained.

<Production Example 5> Production of Prepreg 5 with Plastic Film Support By the solvent method, 1000 glass cloth (thickness 14 μm) manufactured by Arisawa Seisakusho Co., Ltd. is immersed in resin varnish 3, impregnated, and heated to volatilize the solvent. Dry so that the amount of solvent remaining in the prepreg is 0.5% and the thickness is 28 μm, and use a non-silicone release agent (“AL-5” manufactured by Lintec Co., Ltd.) from both sides. The release surface of the release-treated PET film ("Lumilar T6AM" manufactured by Toray Co., Ltd., thickness 38 μm) and the polypropylene film ("Alfan MA-411" manufactured by Oji Special Paper Co., Ltd., thickness 15 μm) The rough surface side was bonded to obtain a prepreg 5 (prepreg 5) with a plastic film support.

The thickness of the resin composition layer of the resin sheet 1, the prepreg 2, the resin sheet 3, the resin sheet 4 and the prepreg 5 (in the case of the prepreg, the thickness including the glass cloth) is determined by the contact type layer thickness gauge (Co., Ltd.). ) Mitutoyo, MCD-25MJ) was used for measurement.

As the sample according to Example 1, a resin sheet 1 was used, and the Ra value (surface roughness) of the surface of the conductor layer was set to 270 (nm) by the above roughening treatment, and 30 at 120 ° C. in the step (3). It was prepared by heating for 30 minutes at 175 ° C. for 30 minutes and then thermosetting the resin composition layer to form an insulating layer.

Further, the sample according to Example 2 was prepared in the same manner as in Example 1 except that the Ra value on the surface of the conductor layer was set to 160 (nm) by the flat bond treatment.

The sample according to Example 3 was prepared in the same manner as in Example 1 except that prepreg 2 was used as the resin sheet with a plastic film support.

Further, the sample according to Example 4 was prepared in the same manner as in Example 2 except that the resin sheet 3 was used.

The sample according to Comparative Example 1 was prepared in the same manner as the sample according to Example 1 except that the resin composition layer was heat-cured to form an insulating layer by heating at 165 ° C. for 30 minutes in the step (3) above. ..

The sample according to Comparative Example 2 was formed in the same manner as in Comparative Example 1 except that the Ra value (surface roughness) of the surface of the conductor layer was set to 160 (nm) by the flat bond treatment.

The sample according to Comparative Example 3 was prepared in the same manner as in Example 1 except that the resin sheet 4 was used as the resin sheet with the plastic film support.

The sample according to Comparative Example 4 was prepared in the same manner as in Example 1 except that the prepreg 5 was used as the resin sheet with the plastic film support.

The sample preparation conditions, modes and evaluation results of Examples 1 to 4 are shown in Table 2 below, and the sample preparation conditions, modes and evaluation results of Comparative Examples 1 to 4 are shown in Table 3 below.

As is clear from Tables 2 and 3, in the circuit boards according to Examples 1 to 4 in which the top diameter (Z), the minimum diameter (Y), and the bottom diameter (X) of the via hole 40 satisfy a predetermined relationship, the laser is used. The thermal cycle test revealed that even when a via hole having a small diameter is formed by irradiation, it is possible to effectively suppress the occurrence of problems over time such as cracks in the conductor layer and the insulating layer. Therefore, according to the present invention, since deterioration of characteristics with time is suppressed, reliability can be improved, product life can be extended, and a thin circuit board can be provided. ..

10 Circuit board 20 Wiring board 22 Board 24 Conductor layer 24a Conductor layer surface 30 Insulation layer 30X Resin composition layer 30a Insulation layer surface 40 Via hole 42 Gouged part 44 Bottom 50 Plastic film support 60 Resin sheet with plastic film support 70 Wiring layer X Bottom diameter Y Minimum diameter Z Top diameter t Insulation layer thickness d Via hole depth

Claims (9)

A circuit board having a conductor layer and an insulating layer covering the conductor layer, and having a via hole for exposing a part of the conductor layer from the insulating layer.
The insulating layer is a cured product of a resin composition containing an epoxy resin, a curing agent, and an inorganic filler.
The arithmetic mean roughness of the surface of the conductor layer is 350 nm or less.
The depth of the via hole is 25 μm or less,
The top diameter (Z) of the via hole is 50 μm or less.
The relationship between the top diameter (Z) of the via hole, the minimum diameter (Y) of the via hole, and the bottom diameter (X) of the via hole is Y / Z = 0.7 to 0.99 and Y / X = 0.7. A circuit board that satisfies ~ 1 (Z> Y). The circuit board according to claim 1 , wherein the curing agent is at least one selected from the group consisting of a phenol-based curing agent, a naphthol-based curing agent, an active ester-based curing agent, and a cyanate ester-based curing agent. The circuit board according to claim 1 or 2 , wherein the curing agent contains an active ester-based curing agent. The circuit board according to any one of claims 1 to 3 , wherein the position of the minimum diameter is located closer to the conductor layer with respect to the depth of the via hole. The circuit board according to any one of claims 1 to 4 , wherein the arithmetic average roughness of the surface of the conductor layer is 300 nm or less. The circuit board according to any one of claims 1 to 5 , wherein the adhesion strength between the conductor layer and the insulating layer is 0.15 kgf / cm or more. The circuit board according to any one of claims 1 to 6 , wherein the adhesion strength between the conductor layer and the insulating layer is 0.2 kgf / cm or more. The circuit board according to any one of claims 1 to 7 , wherein the top diameter (Z) of the via hole is 40 μm or less. A semiconductor device including the circuit board according to any one of claims 1 to 8 .

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