JP2016035969A - Circuit board and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a circuit board including an insulating layer whose thickness covering a conductor laser having a small surface roughness is thinner and capable of suppressing problems which occur with age even when a small-diameter via hole is farmed due to laser irradiation.SOLUTION: A circuit board 10 comprises a conductor layer 24, an insulating layer 30 covering the conductor layer, and a via hole 40 through which a part of the conductor layer is exposed from the insulating layer. The arithmetic average roughness of a surface 24a of the conductor layer is not more than 350 nm, the depth of the via hole is not more than 30 μm, and the top diameter (Z) of the via hole is not more than 50 μm. The relationship between the top diameter (Z), minimum diameter (Y), and bottom diameter (X) of the via hole satisfies "Y/Z=0.7 to 0.99 and Y/X=0.7 to 1(Z>Y)".SELECTED DRAWING: Figure 1

Description

  The present invention relates to a circuit board and a manufacturing method thereof.

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

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

  As one of the causes of electrical signal attenuation in circuit boards, it is known that the surface roughness of the conductor layer including the wiring is large, and suppression of electrical signal attenuation due to the large surface roughness of the conductor layer is suppressed. In order to achieve this, it is desired to reduce the surface roughness of the conductor layer. In particular, when high-frequency electrical signals are used, transmission loss due to the large surface roughness of the conductor layer is significant, and so-called high-frequency circuit boards that require high-speed transmission of electrical signals for servers and the like are particularly conductive layers. It is desirable to reduce the surface roughness of the material.

JP 2008-37957 A

  In view of the above points, the inventors of the present invention have reduced the surface roughness of the conductor layer, and applied via holes to the insulating layer of the circuit board in which the insulating layer covering the conductor layer has been made thinner. When the surface of the conductor layer is formed, the laser beam is reflected and diffused on the surface of the conductor layer, so that the insulating layer near the conductor layer is crushed and inevitably a crease is formed, and a via hole with a smaller top diameter is formed. It has been found that when formed, problems such as the occurrence of cracks in the conductor layer and the insulating layer due to the bent portions can occur over time.

  Accordingly, an object of the present invention is to reduce the surface roughness of the conductor layer in a thin circuit board having a thinner insulating layer, and to form a small-diameter via hole in the insulating layer by laser irradiation. Even if it exists, it is providing the circuit board which does not produce the malfunction over time by use, such as generation | occurrence | production of a crack.

  As a result of intensive studies on the above problems, the present inventors have determined that the adhesion strength between the conductor layer and the insulating layer of the circuit board is 0.15 kgf / cm or more, the top diameter (Z) of the via hole and the maximum of the via hole. 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). As a result, the present invention has been completed.

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 a via hole exposing a part of the conductor layer from the insulating layer,
The arithmetic average roughness of the surface of the conductor layer is 350 nm or less,
The via hole has a depth of 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 when the depth of the via hole is used as a reference.
[3] The circuit board according to [1] or [2], wherein the arithmetic average 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 a depth of the via hole is 25 μm or less.
[5] The circuit board according to any one of [1] to [4], wherein an 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 an 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 a 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 comprising the circuit board according to any one of [1] to [9].
[11] Step (A) A resin sheet with a plastic film support including a 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. Bonding to the conductor layer of the wiring substrate provided with a conductor layer including a conductor pattern;
Step (B) The resin composition layer is heat-cured to provide an insulating layer having a thickness on the conductor layer of 30 μm or less, and an adhesion strength between the insulating layer and the conductor layer is 0.15 kgf / cm or more Forming an insulating layer,
Step (C) A laser is irradiated from the plastic film support side to form a via hole having a top diameter (Z) of 50 μm or less on the insulating layer, the top diameter (Z) of the via hole and the minimum diameter (Y ) And the bottom diameter (X) of the via hole, the step of forming the via hole satisfying Y / Z = 0.7 to 0.99 and Y / X = 0.7 to 1 (Z>Y); ,
Step (D) performing a desmear process;
Step (E) peeling the plastic film support from the insulating layer;
And (F) forming a further conductor layer on the insulating layer.
[12] In the above 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 via hole is based on the depth of the via hole. Circuit board manufacturing method.
[13] The method for manufacturing a circuit board according to [11] or [12], wherein the desmear process in the step (D) is a wet desmear process.
[14] The step (F) is a step of forming a metal layer by dry plating on the surface of the insulating layer and forming the conductor layer by wet plating on the surface of the metal layer. ] The manufacturing method of the circuit board as described in 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 manufacturing a circuit board according to any one of [11] to [15], wherein the resin composition layer includes an epoxy resin, a curing agent, and an inorganic filler.
[17] The method for manufacturing a circuit board according to [16], wherein the inorganic filler has an average particle diameter of 0.01 μm to 3 μm.
[18] The method for manufacturing a circuit board according to [16], wherein the inorganic filler has an average particle diameter of 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 nonvolatile component in the resin composition layer is 100% by mass. [18] 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 having a thinner insulating layer covering a conductor layer having a small surface roughness, cracks are generated in the conductor layer and the insulating layer even when a small diameter via hole is formed by laser irradiation. Thus, it is possible to provide a circuit board that is less likely to cause problems over time due to use.

FIG. 1 is a schematic diagram showing a circuit board in a plan view. FIG. 2 is a schematic diagram showing an end surface taken along the dashed line II-II in FIG. FIG. 3 is a schematic view for explaining a circuit board manufacturing method. FIG. 4 is a schematic view for explaining a circuit board manufacturing method.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Each drawing only schematically shows the shape, size, and arrangement of the components to the extent that the invention can be understood. The present invention is not limited to the following description, and each component can be appropriately changed without departing from the gist of the present invention. In the drawings used for the following description, the same components are denoted by the same reference numerals, and overlapping descriptions may be omitted. In addition, the configuration according to the embodiment of the present invention is not necessarily manufactured and used in the illustrated arrangement and shape.

[Circuit board comprising a conductor layer and an insulating layer covering the conductor layer]
The circuit board of the present invention is a circuit board comprising a conductor layer and an insulating layer covering the conductor layer, and a via hole exposing a part of the conductor layer from the insulating layer, the arithmetic average roughness of the surface of the conductor layer 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.
FIG. 1 is a schematic diagram showing a circuit board in a plan view. The area of the circuit board in which one via hole is provided is shown enlarged. FIG. 2 is a schematic diagram showing an end surface cut along a dashed line II-II in FIG. 1.

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

  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 sides of the substrate 22, and the build-up layer is provided on both sides 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, 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 in order to simplify the description and make it easier to understand.

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

  The thickness of the insulating layer 30 according to this embodiment on the conductor layer 24 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 thinner as a whole.

  Although the detail of the manufacturing method of the insulating layer 30 is mentioned later, the insulating layer 30 is comprised as a hardened | cured material of a resin composition. This hardened | cured material may be formed using the 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 that are exposed 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) that is a diameter (opening diameter) of a substantially circular contour defined on the surface 30a of the insulating layer 30 of 50 μm or less, preferably 40 μm or less. In other words, the via hole 40 provided in the circuit board 10 of the present invention is provided as a via hole whose 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.

  Although the details of the method of forming the via hole 40 will be described later, the via hole 40 is preferably formed by irradiating a laser.

  The via hole 40 of the present embodiment has a Y / Z range of 0.7 to 0.99 (Y / Z) in relation to the 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 this embodiment, the depth d extends in the via hole 40 in a direction perpendicular 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. Corresponds to the length of the line segment at the position where the end of the line 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 more than the position where the distance from the position of the top diameter (Z) or the position of the bottom diameter (X) is equal with respect to the depth d of the via hole 40, that is, the position of d / 2. Position near the conductor layer 24, that is, a position within the range of d / 2 from the bottom 44 (0d) of the via hole 40, which is the bottom diameter (X) side with respect to the depth d of the via hole 40, in other words, the top diameter ( Z) located at a position within the range of 0.5d to 1.0d from the side.

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

  Usually, the contour of the via hole 40 has an inverted frustoconical shape whose top diameter (Z) is larger than the bottom diameter (X). However, the via hole 40 in the illustrated example has a shape from the surface 24 a of the conductor layer 24. A narrow portion 42 is formed in a region near the conductor layer 24. Note that the via hole 40 according to the present embodiment does not have the bent portion 40, the minimum diameter (Y) and the bottom diameter (X) coincide with each other, and the top diameter (Z) is larger than the bottom diameter (X). There may be an inverted frustoconical shape.

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

  In the illustrated example, the rounded portion 42 has a frustoconical shape in which the contour shape is larger in diameter at the bottom surface than at the top surface. However, the shape of the bent portion 42 is not limited to this. The maximum diameter of the bent portion 42 corresponds to the bottom diameter (X) of the bottom portion 44 of the via hole 40 in the illustrated example.

  In the circuit board 10, it is preferable that the bent portion 42 has a smaller diameter (the diameter of the bottom surface and the upper surface of the truncated cone) and the size thereof, and the bent portion 42 does not exist, that is, Y / X becomes 1. Thus, it is more preferable that the shape of the outline 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, more preferably 0.20 kgf / cm or more. As described above, by setting the adhesion strength between the conductor layer 24 and the insulating layer 30 to 0.15 kgf / cm or more, the shape of the outline of the via hole 40 satisfies the above relationship. As a result, the via hole 40 having a smaller diameter of the bent portion 42 and a smaller size of the bent portion 42 can be formed even if the bent portion 42 is not included or unavoidably included. As a result, it is possible to provide a highly reliable circuit board 10 that has a long life because it is less likely to cause problems over time due to the occurrence of cracks in the insulating layer 30 and the conductor layer 24, for example, even when operated with a high-frequency signal. be able to.
On the other hand, when the adhesion strength between the conductor layer 24 and the insulating layer 30 is smaller than 0.15 kgf / cm, the shape of the outline of the via hole 40 cannot satisfy the above relationship, and the diameter and size of the rounded portion 42 are small. Since it becomes large and problems with time such as generation of 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 fear.

  In the illustrated example, a wiring layer 70 is provided on the surface 30 a 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, for example, as a filled via so as to fill the via hole 40, whereby the wiring layer 70 reaches the surface 24 a of the conductor layer 24, and the wiring layer 70 and the conductor layer 24 are separated from each other. Electrically connected.

[Circuit board manufacturing method]
The method for producing a circuit board according to the present embodiment comprises a step (A) a resin sheet with a plastic film support including a plastic film support and a resin composition layer bonded to the plastic film support. A step of bonding to a conductor layer of a wiring board provided with a conductor layer including a conductor pattern having an arithmetic average roughness of 350 nm or less; and a step (B) thermosetting the resin composition layer to obtain a thickness on the conductor layer Forming an insulating layer having a thickness of 30 μm or less and having an adhesion strength between the insulating layer and the conductor layer of 0.15 kgf / cm or more; and step (C) irradiating a laser from the plastic film support side. In addition, the insulating layer is a via hole having a top diameter (Z) of 50 μm or less, and 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. And a step of forming a via hole satisfying Y / Z = 0.7 to 0.99 and Y / X = 0.7 to 1 (Z> Y), a step of performing a step (D) desmear treatment, and a step of (E) The process of peeling a plastic film support body from an insulating layer, and the process (F) The process of forming the further conductor layer in an insulating layer is included.

  With reference to FIG.3 and FIG.4, the manufacturing method of the circuit board concerning this embodiment is demonstrated. 3 and 4 are schematic views for explaining a circuit board manufacturing method shown in the same manner as FIG.

<Process (A)>
In the step (A), a resin sheet with a plastic film support comprising a plastic film support and a resin composition layer bonded to the plastic film support, a conductor having an arithmetic mean roughness of the surface of 350 nm or less It is a step of bonding to a conductor layer of a wiring board provided with a conductor layer including a pattern.

  As shown in FIG. 3, in step (A), a resin sheet 60 with a plastic film support including a plastic film support 50 and a resin composition layer 30X bonded to the plastic film support 50 is prepared. Then, the resin composition layer 30 </ b> X of the resin sheet 60 with a plastic film support is laminated so as to be bonded to the surface 24 a 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, and a thermosetting polyphenylene ether substrate. As described above, a conductor layer (circuit) 24 including one or more patterned wiring patterns is formed on one surface (or both surfaces) 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 electrical signal. The surface roughness of the conductor layer 24 can be adjusted by the surface treatment of the conductor layer 24.

  An example of the surface treatment of the surface 24a of the conductor layer 24 that 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 is an organic acid microetching agent. Roughening treatment using “MEC etch bond CZ8100” and “MEC etch bond CZ8101” (manufactured by MEC), “Secure HFz” (manufactured by Atotech), “flat bond” (MEC And surface treatment by tin-based treatment using (made by)). Here, the tin-based treatment means that a layer containing at least metal tin or tin oxide is formed on the surface 24 a of the conductor layer 24. Specifically, the surface treatment is performed on the wiring board 20 by performing a treatment such as a substitution tin plating, a tin salt, an organic and / or inorganic acid, a treatment solution containing a reducing agent, or the like.

  The structure of the resin sheet 60 with a plastic film support used in the step (A) and details of the production method will be described later.

  The resin sheet 60 with a plastic film support and the wiring substrate 20 are joined (laminated) by, for example, a thermocompression bonding process in which the resin sheet 60 with a plastic film support is thermocompression bonded to the wiring substrate 20 from the plastic film support 50 side. It can be carried out. As a member (hereinafter also referred to as a “heat-bonding member”) for heat-pressing the resin sheet 60 with a plastic film support to the wiring substrate 20, for example, a heated metal plate (SUS mirror plate or the like) or a metal roll (SUS roll). ) And the like. Instead of directly pressing the thermocompression bonding member on the resin sheet 60 with a plastic film support, heat-resistant rubber or the like is used as a material so that the resin composition layer 30X sufficiently follows the irregularities on the surface of the circuit board 20. It is preferable to press through an elastic material.

  The temperature in the thermocompression bonding step is preferably in the range of 80 ° C to 160 ° C, more preferably in the range of 90 ° C to 140 ° C, and still more preferably in the range of 100 ° C to 120 ° C. The pressure in the thermocompression bonding 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 thermocompression bonding step is preferably in the range of 20 seconds to 400 seconds, and more preferably in the range of 30 seconds to 300 seconds. The lamination is preferably performed under reduced pressure conditions where the pressure is 26.7 hPa or less.

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

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

  After the lamination, the resin sheet 60 with the plastic film support may be smoothed by pressing the thermocompression bonding member from the plastic film support 50 side, for example, under normal pressure (atmospheric pressure). . The pressing conditions for the smoothing treatment can be the same as the conditions in the thermocompression bonding step. The smoothing treatment can be performed with a commercially available laminator. In addition, you may perform lamination | stacking and a smoothing process continuously using said commercially available vacuum laminator.

<Process (B)>
In the step (B), the resin composition layer 30X is heat-cured to form an insulating layer 30 having a thickness on the conductor layer 24 of 30 μm or less, and the adhesion strength between the insulating layer 30 and the conductor layer 24 is 0.15 kgf. This is a step of forming the insulating layer 30 that is at least / cm.

  In the step (B), the resin composition layer 30X is thermoset to form the insulating layer 30. You may peel the plastic film support body 50 from the resin composition layer 30X before thermosetting. In the case where the surface of the plastic film support 50 is subjected to a release treatment and the release-treated surface and the resin composition layer 30X are in contact with each other, after the formation of the insulation layer 30, the surface 30a of the insulation layer 30 can be easily formed. When the plastic film support 50 can be peeled off, the insulating layer 30 can also be formed by thermosetting the plastic film support 50 as it is without peeling.

  In the step (B), the thermosetting conditions of the resin composition layer 30X are not particularly limited. 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. And a 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). Moreover, the pressure at the time of thermosetting is not specifically limited, Any of normal pressure, pressurization, and pressure reduction may be sufficient.

  Before heat-curing the resin composition layer 30X, a pre-heating treatment in which the resin composition layer 30X is heat-treated at a temperature lower than the curing temperature may be performed. For example, prior to thermosetting the resin composition layer 30X, the resin composition layer 30X is kept 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). You may perform the preheating process which heat-processes (-150 minutes).

  The thickness on the conductor layer 24 of the insulating layer 30 formed by thermosetting the resin composition layer 30 </ b> X, 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 reducing the thickness, the thickness of the insulating layer 30 on the conductor layer 24 is preferably 25 μm or less. Although the minimum of the thickness on the conductor layer 24 of the insulating layer 30 is not specifically limited, Usually, it is 3 micrometers 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 adjusted as appropriate by adjusting the thickness of the resin composition layer 30X of the resin sheet 60 with a plastic film support. be able to.

  The adhesion strength between the insulating layer 30 formed by thermosetting the resin composition layer 30X and the conductor layer 24 is set to 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, the insulating layer 30 is reflected and diffused by the laser beam on the surface 24a of the conductor layer 24 located on the bottom 44 side of the via hole 40 when the via hole 40 is formed by laser irradiation. In some cases, the conductor layer 24 may be peeled off by the heat of the laser energy.

  The adhesion strength between the formed insulating layer 30 and the conductor layer 24 is determined based on the components of the resin composition for forming the insulating layer 30 and the curing conditions for forming the insulating layer 30 (the glass of the resin 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 resin composition component, a resin composition mainly composed of an epoxy resin is used, and a phenol-based curing agent or an active ester-based curing is used as a curing agent. It is preferable to use an agent. As a curing condition for such a resin composition, it is preferable to cure under such a curing condition that Tg of the cured product of the resin composition is 100 ° C. or more. When an epoxy resin having a triazine structure and a phenolic curing agent having a triazine structure are 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 also when a vinyl polymerization resin is used as a component of the resin composition The strength tends to decrease.

  As the surface roughness of the surface 24a of the conductor layer 24 increases, the adhesion strength between the insulating layer 30 and the conductor layer 24 tends to improve due to the so-called anchor effect. However, signal transmission loss tends to increase as the surface roughness of the surface 24a of the conductor layer 24 increases. 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. In addition, by performing a surface treatment for improving the adhesion strength on the surface 24 a of the conductor layer 24, the adhesion strength between the insulating layer 30 and the conductor layer 24 can be improved.

  Examples of surface treatments that can improve adhesion strength while reducing the surface roughness 24a of the conductor layer 24 include “MEC etch bond CZ8100” and “MEC etch bond CZ8101” (MEC etch bonds) that are organic acid microetching agents. And a roughening treatment using a product manufactured by (Co., Ltd.). Examples of the surface treatment for improving the adhesion strength of the surface 24a of the conductor layer 24 include surface treatment with “Secure HFz” (manufactured by Atotech), which is a tin-based treatment agent. Moreover, after performing the process for improving a roughening process and adhesive strength, you may improve adhesive strength by giving the process which uses a coupling agent further. Examples of coupling agents that can be used include silane coupling agents, titanate coupling agents, aluminate coupling agents, 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, and a styrene silane coupling agent. Examples of such surface treatment include surface treatment by “flat bond” (manufactured by MEC Co., Ltd.) including treatment with a tin-based treatment agent and treatment with a coupling agent.

  In the method for 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 via hole 40 to be formed 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 when the depth d of the via hole 40 is used as a reference.

<Process (C)>
The circuit board 10 according to the present embodiment can be manufactured, for example, by performing the step (C) after performing the step (A) and the step (B).
Step (C) is a via hole 40 having a top diameter (Z) of 50 μm or less on the insulating layer 30 by irradiating a laser from the plastic film support 50 side, that is, from 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 that satisfies ˜1 (Z> Y).

  As shown in FIG. 4, in 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 bonded to the insulating layer 30 as in the illustrated example, the plastic film support 50 may be irradiated with 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 a laser. From the viewpoint of forming the via hole 40 with high accuracy, it is preferable to form the via hole 40 by irradiating the laser from above without peeling off the plastic film support 50.

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

  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 to be formed may be the same or different from each other. Note that 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, a via hole 40 having a top diameter (Z) exceeding 50 μm may be formed together.

  The relationship between 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 formed by the method of manufacturing the circuit board 10 according to the present embodiment is Y / Z = 0.7-0.99, and Y / X = 0.7-1 (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.

Examples of laser light sources that can be used for laser irradiation in the step (C) include carbon dioxide laser, YAG laser, UV-YAG laser, YVO ₄ laser, YLF laser, and excimer laser. Any suitable laser light source can be used according to the light absorption characteristics of the plastic film support 50 and the insulating layer 30.

  The laser irradiation conditions are not particularly limited as long as the small-diameter via hole 40 having the top diameter (Z) as already described can be formed, and the type of the laser light source, the presence or absence of the plastic film support 50, its thickness, Depending on the thickness, type, and the like of the insulating layer 30, it may be determined as appropriate. Hereinafter, irradiation conditions when a carbon dioxide laser is used as the laser light source will be described. When a carbon dioxide gas laser is used as the laser light source, laser light having a wavelength of 9.3 μm to 10.6 μm is generally used. The number of shots varies depending on the depth d and top diameter (Z) of the via hole 40 to be formed, but is usually selected in the range of 1 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 smaller, 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 a burst mode or a cycle mode. The energy of the laser depends on the number of shots, the depth d of the via hole 40, the presence or 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 even more preferably 0. Set to 4 mJ or higher. The upper limit of the laser energy is preferably 20 mJ or less, more preferably 15 mJ or less, and even more preferably 10 mJ or less.

  Step (C) can be performed using a commercially available laser device. As a commercially available laser device, for example, “LC-2E21B / 1C” (carbon dioxide laser device) manufactured by Hitachi Via Mechanics Co., Ltd., “605GTWIII (−P)” (carbon dioxide laser device) manufactured by Mitsubishi Electric Corporation, Examples thereof include “MODEL 5330xi” and “MODEL 5335” (UV-YAG laser apparatus) manufactured by ESI.

  In general, resin residues (smear) adhere 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 process (step (D)) for removing smear is usually performed after the via hole 40 is formed.

<Process (D)>
A process (D) is a process of performing a desmear process.
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, for example, by 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. Alternatively, it may be performed in a state of being bonded to the insulating layer 30.

  An example of the dry desmear process is a desmear process using plasma. The desmear treatment using plasma can be performed using a commercially available plasma desmear treatment apparatus. Among the commercially available plasma desmear treatment apparatuses, as examples suitable for the production of the circuit board of the present invention, a microwave plasma apparatus manufactured by Nissin Co., Ltd., an atmospheric pressure plasma etching apparatus manufactured by Sekisui Chemical Co., Ltd. and the like can be mentioned. It is done.

  As an example of the dry desmear process, there is a dry sand blast process in which an abrasive is sprayed from a nozzle to polish a processing target. The dry sand blast treatment can be carried out using a commercially available dry sand blast treatment apparatus. In the case of using a water-soluble abrasive as the abrasive, it is possible to effectively remove smear without leaving the abrasive in the via hole 40 by washing with water after the dry sandblast treatment. .

  Examples of the wet desmear process include a desmear process using an oxidant solution. When desmear treatment is performed using an oxidizing agent solution, it is preferable to perform a swelling treatment with a swelling liquid, an oxidation treatment with an oxidizing agent solution, and a neutralization treatment with a neutralizing solution in this order. Examples of the swelling liquid include “Swelling Dip Securigans P” and “Swelling Dip Securigans SBU” manufactured by Atotech Japan Co., Ltd. The swelling treatment is preferably performed 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 minutes to 10 minutes. The oxidant solution is preferably an aqueous alkaline permanganate 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 oxidant solution is preferably performed by immersing the substrate after the swelling treatment in an oxidant solution heated to 60 ° C. to 80 ° C. for 10 minutes to 30 minutes. Examples of commercially available alkaline permanganate aqueous solutions include “Concentrate Compact CP” and “Dosing Solution Securigans P” manufactured by Atotech Japan Co., Ltd. The neutralization treatment with the neutralization solution is preferably performed by immersing the oxidized substrate in a neutralization solution at 30 ° C. to 50 ° C. for 3 to 10 minutes. As the neutralizing solution, an acidic aqueous solution is preferable, and as a commercially available product, for example, “Reduction Solution Securigant P” manufactured by Atotech Japan Co., Ltd. can be mentioned.

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

  When the dry desmear process and the wet desmear process are performed in combination, the dry desmear process may be performed first, or the wet desmear process may be performed 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)>
Step (E) is a step of peeling the plastic film support 50 from the insulating layer 30.
The peeling method of the plastic film support body 50 is not specifically limited, It can carry out by a conventionally well-known arbitrary suitable method. The plastic film support 50 can be mechanically peeled off by an automatic peeling device.

<Process (F)>
Step (F) is a step of forming the wiring layer 70 on the insulating layer 30.
After the desmear process, a 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. The metal is included as a material. The wiring layer 70 may be a single metal layer or an alloy layer. As the alloy layer, for example, an alloy of two or more kinds of metals selected from the above group (for example, nickel-chromium alloy, copper -Nickel alloy and copper-titanium alloy). The wiring layer 70 is a single metal layer of chromium, nickel, titanium, aluminum, zinc, gold, palladium, silver, or copper, among others, from the viewpoint of ease of forming the wiring layer 70, cost, ease of patterning, etc. It is preferably an alloy layer of nickel / chromium alloy, copper / nickel alloy, copper / titanium alloy, single metal layer of chromium, nickel, titanium, aluminum, zinc, gold, palladium, silver or copper, or nickel / chromium alloy The alloy layer is more preferably a copper single metal layer.

  The wiring layer 70 may have a single layer structure or a multilayer structure in which two or more single metal layers or alloy layers made of different types of metals or alloys are stacked. When the wiring layer 70 has a multilayer structure, the layer bonded 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 is usually 35 μm or less, preferably 30 μm or less, more preferably 25 μm or less, although it depends on the desired circuit board design. 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) comprises
Forming a metal layer on the surface of the insulating layer 30 by dry plating;
A step of forming the wiring layer 70 on the surface of the metal layer by wet plating in this order (hereinafter referred to as “process (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 dry plating include physical vapor deposition (PVD) methods such as vapor deposition, sputtering, ion plating, and laser ablation, and chemical vapor deposition (CVD) methods such as thermal CVD and plasma CVD. Sputtering is preferred. The metal layer may be formed by combining two of these dry platings.

  Although the thickness of the metal layer formed is not specifically limited, Preferably it is 5 nm-2 micrometers, More preferably, it is 10 nm-1 micrometer, More preferably, it is 20 nm-500 nm. The metal layer may have a single layer structure or a multilayer structure. When the metal layer has a multilayer structure, the thickness of the entire metal layer is preferably in the above range.

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

  Using the metal layer as a plating seed layer, the wiring layer 70 including a wiring pattern having a desired pattern can be formed by wet plating using 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 the wiring layer 70 is formed by electrolytic plating on the exposed plating seed layer, the mask pattern is removed. Thereafter, an unnecessary plating seed layer can be removed by etching or the like to form a wiring layer 70 including a desired wiring pattern.

In forming the wiring layer 70, the surface 30a of the insulating layer 30 may be roughened. In this case, the step (F-1)
Roughening the surface 30a of the insulating layer 30;
Forming a metal layer on the surface 30a of the insulating layer 30 by dry plating;
Forming a wiring layer 70 on the surface of the metal layer by wet plating in this order.

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

In another preferred embodiment, step (F) comprises
Roughening the surface 30a of the insulating layer 30;
And a step of forming the wiring layer 70 on the surface 30a of the insulating layer 30 by wet plating in this order (hereinafter referred to as “process (F-2)”).

  The details of the roughening process are as already 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, the wiring layer 70 including a wiring pattern having a desired pattern can be formed by a semi-additive method by combining electroless plating and electrolytic plating.

  Since the surface roughness of the surface 30a of the resulting insulating layer 30 can be further reduced and contributes to finer and higher density wiring, the step (F-1) is performed as the step (F). Is preferred.

  The circuit board 10 is manufactured through 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 production 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 bonded to the plastic film support 50. Hereinafter, these will be described.

(Plastic film support)
Examples of the material for 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 polymethyl methacrylate (“ Acrylic, cyclic polyolefin, triacetyl cellulose (referred to as “TAC”), polyether sulfide (referred to as “PES”), polyether ketone, polyimide, and the like. Among these, PET, PEN, and polyimide are preferable, and PET and PEN are more preferable. In a 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 form a via hole 40 having a small diameter in the insulating layer 30 by irradiating a laser from above the plastic film support 50 side. From the viewpoint of smoothly forming the via hole 40 by laser irradiation, the plastic film support 50 is preferably capable of absorbing 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.

  By incorporating a laser energy absorbing component into the plastic film support 50, the laser energy absorbing property may be imparted or increased. 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. A laser energy absorption component may be used individually by 1 type, and may be used in combination of 2 or more type.

  Examples of the carbon powder include powders of carbon black such as furnace black, channel black, acetylene black, thermal black, anthracene black, graphite powder, and a mixture thereof. Examples of the metal compound powder include titania such as titanium oxide, magnesia such as magnesium oxide, iron oxide such as iron oxide, nickel oxide such as nickel oxide, zinc oxide such as manganese dioxide and zinc oxide, Silicon, aluminum oxide, rare earth oxide, cobalt oxide such as cobalt oxide, tin oxide such as tin oxide, tungsten oxide such as tungsten oxide, silicon carbide, tungsten carbide, boron nitride, silicon nitride, titanium nitride, aluminum nitride , Barium sulfate, rare earth oxysulfides, and mixtures thereof. Examples of the metal powder include silver, aluminum, bismuth, cobalt, copper, iron, magnesium, manganese, molybdenum, nickel, palladium, antimony, silicon, tin, titanium, vanadium, tungsten, zinc, and alloys or mixtures thereof. Examples thereof include powder. Examples of black dyes include azo (monoazo, disazo, etc.) dyes, azo-methine dyes, anthraquinone dyes, quinoline dyes, ketone imine dyes, fluorone dyes, nitro dyes, xanthene dyes, acenaphthene dyes, quinophthalone dyes, aminoketone dyes, methine dyes. Perylene dye, coumarin dye, perinone dye, triphenyl dye, triallylmethane dye, phthalocyanine dye, incrophenol dye, azine dye, and mixtures thereof. In order to improve dispersibility, it is preferable to use a black dye that is soluble in a solvent. Among these, as the laser energy absorbing component, carbon powder is preferable from the viewpoint of conversion efficiency of laser energy to heat, versatility, and the like, and carbon black is particularly preferable. In addition, the upper limit of the average particle diameter of the laser energy absorbing component is preferably 20 μm or less, more preferably 10 μm or less, from the viewpoint of efficiently absorbing laser energy. The lower limit of the average particle diameter is preferably 0.001 μm or more, more preferably 0.002 μm from the viewpoint of dispersibility. The “average particle diameter” as used herein can be measured by a particle size distribution measuring apparatus or BET method. The BET method is a method in which molecules having a known adsorption occupation 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. Furthermore, the average particle diameter can be calculated from the specific surface area determined 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. Preferably it is 0.03 mass%, More preferably, it is 0.05 mass% or more. The upper limit of the content is preferably 40% by mass or less, more preferably 20% by mass or less, and still more preferably 10% by mass or less from the viewpoint of obtaining a plastic film support 50 having good flexibility. It is. In addition, the laser energy absorptive component may be contained in the mold release layer mentioned later.

  Commercially available plastic film supports 50 include, for example, “Lumilar R56”, “Lumilar R80”, “Lumilar T6AM” (PET film) manufactured by Toray Industries, Inc., “G2LA” (manufactured by Teijin DuPont Films) PET film), "Teonex Q83" (PEN film), "Upilex-S" (polyimide film) manufactured by Ube Industries, Ltd., "Apical AH", "Apical NPI" (polyimide film) manufactured by Kaneka Corporation, etc. Is mentioned.

  The plastic film support 50 may be subjected to a mat treatment or a corona treatment on the surface bonded to the resin composition layer 30X.

  Since it is easy to adjust the adhesion strength between the insulating layer 30 and the plastic film support 50 in a desired range in the step (B), the plastic film support 50 is separated 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 preferred. Examples of the release agent that can be used for the release layer include non-silicone release agents such as alkyd resins, melamine resins, olefin resins, and urethane resins, and silicone release agents. A mold release agent may be used individually by 1 type, and may be used in combination of 2 or more type. In particular, when producing the resin sheet 60 with a plastic film support, it exhibits high wettability with respect to the resin varnish, and the contact state with the resin composition layer 30X tends to be uniform over the entire surface. 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 peel strength, a so-called heavy release type release agent having a high peel strength, or a light release type release agent, depending on the type of constituent components. Can be classified as a so-called intermediate release type release agent that exhibits intermediate peel strength between the heavy release type release agent and the heavy release type release agent, but it is easy to adjust the adhesion strength to a desired range in step (B). A release type release agent is preferred. Although it depends on the composition of the resin composition layer 30X for forming the insulating layer 30, the lamination conditions in the step (A), the thermosetting conditions in the step (B), etc., the release agent has an initial adhesion strength. 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) / 20mm) or more, 900 (mN / 20mm) or more, or 1000 (mN / 20mm) or more release agent 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 the plastic film support 50 in the step (E). And so on. The initial adhesion strength was determined by applying an acrylic adhesive tape (“31B” manufactured by Nitto Denko Corporation) using a 2 kg roller to the surface that had been subjected to a release treatment with a release agent, and letting it stand for 30 minutes. Can be obtained by measuring the load (mN / 20 mm) when it is peeled off and gripped with a gripper and peeled off at room temperature, at a speed of 30 cm / min, and at a peeling angle of 180 °. The measurement may be performed using, for example, a tensile tester such as “AC-50C-SL” manufactured by TSE Corporation.

  Examples of commercially available release agents include “X” (silicone-containing alkyd resin release agent; 490 mN / 20 mm) and “SK-1” (silicone-containing alkyd resin release agent) manufactured by Lintec Corporation. 1250 mN / 20 mm), “AL-5” (non-silicone alkyd resin release agent; 1480 mN / 20 mm), “6050” (non-silicone alkyd resin release agent; 2400 mN / 20 mm), “6051” (non- Silicone alkyd resin release agent: 2800 mN / 20 mm), “6052” (non-silicone alkyd resin 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 release agent; heavy release type) manufactured by Lintec Corporation, and “NSP-4” manufactured by Fujimori Kogyo Co., Ltd. ( Non-silicone alkyd resin release agent; heavy release type).

  Although the thickness of the plastic film support body 50 is not specifically limited, It is preferable that it is the range of 10 micrometers-100 micrometers, and it is more preferable that it is the range of 15 micrometers-75 micrometers. In particular, from the viewpoint of facilitating the formation of small diameter vias, it is more preferably in the range of 20 μm to 50 μm. In addition, when the plastic film support body 50 is the plastic film support body 50 with a release layer, it is preferable that the thickness of the whole plastic film support body 50 with a release layer is the said range.

(Resin composition layer)
The resin composition used for the resin composition layer 30 </ b> X is not particularly limited as long as the cured product has sufficient hardness and insulation and provides desired adhesion strength to 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 as 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, naphthol novolak 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, glycidyl amine type epoxy resin, glycidyl ester type epoxy resin, cresol novolac type epoxy resin, biphenyl type Epoxy resin, linear aliphatic epoxy resin, epoxy resin having butadiene structure, alicyclic epoxy resin, heterocyclic epoxy resin, spiro ring Epoxy resins, cyclohexanedimethanol type epoxy resins, naphthylene ether type epoxy resins and trimethylol type epoxy resins. The illustrated epoxy resins 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 nonvolatile component of the epoxy resin is 100% by mass, at least 50% by mass 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 having three or more epoxy groups in one molecule. And an epoxy resin that 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 an epoxy resin, a resin composition having excellent flexibility can be obtained. Moreover, 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 Corporation, 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 & Sumikin Chemical Co., Ltd.) Products), "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 Industries, Ltd. It is done. These may be used alone or in combination of two or more.

  Solid epoxy resins 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, naphthylene ether type epoxy resin, An anthracene type epoxy resin is preferable, and a naphthalene type tetrafunctional epoxy resin, a naphthol type epoxy resin, and a 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) manufactured by DIC Corporation, “ N-695 ”(cresol novolac type epoxy resin),“ HP-7200 ”(dicyclopentadiene type epoxy resin),“ EXA7311 ”,“ EXA7311-G3 ”,“ EXA7311-G4 ”,“ EXA7311-G4S ”,“ HP6000 ” ”(Naphthylene 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) Epoxy resin), “ESN475V” (naphthol type epoxy resin) manufactured by Nippon Steel & Sumikin Chemical Co., Ltd., “ESN485V” (naphthol novolac type epoxy resin), “YX4000H”, “YL6121” (biphenyl type) manufactured by Mitsubishi Chemical Corporation Epoxy resin), "YX4000HK" (bixylenol type epoxy resin), "YX8800" (anthracene type epoxy resin), "PG-100", "CG-500" manufactured by Osaka Gas Chemical Co., Ltd., Mitsubishi Chemical Corporation "YL7800" (fluorene type epoxy resin) manufactured by the same, etc. are mentioned.

  When the liquid epoxy resin and the solid epoxy resin are used in combination as the epoxy resin, the quantitative ratio thereof (liquid epoxy resin: solid epoxy resin) is in the range of 1: 0.1 to 1: 6 by mass ratio. It is preferable to do. By setting the amount ratio of the liquid epoxy resin and the solid epoxy resin within such a range, i) suitable adhesiveness is obtained when used in the form of a resin sheet with a plastic film support, and ii) a plastic film support. When used in the form of a resin sheet with adhesive, sufficient flexibility is obtained, handling properties are improved, and iii) a cured product having sufficient breaking strength can be obtained. From the viewpoint of the effects i) to iii) above, the quantitative ratio of liquid epoxy resin to solid epoxy resin (liquid epoxy resin: solid epoxy resin) is from 1: 0.3 to 1: 5 in mass ratio. The range is more preferable, and the range of 1: 0.6 to 1: 4.5 is more preferable.

  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, unless otherwise specified, the content of each component in the resin composition is a value when the nonvolatile component in the resin composition is 100% by mass.

  The weight average molecular weight of an epoxy resin becomes like this. Preferably it is 100-5000, More preferably, it is 250-3000, More preferably, it is 400-1500. Here, the weight average molecular weight of the epoxy resin is a weight average molecular weight in terms of polystyrene 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 still more preferably 110 to 1000. By setting it as this range, the crosslinking density of hardened | cured material becomes sufficient and it can bring about an insulating layer with small surface roughness. In addition, an epoxy equivalent can be measured in accordance with the method prescribed | regulated by JISK7236, and is the mass of resin containing 1 equivalent of epoxy groups.

-Curing agent-
The curing agent is not particularly limited as long as it has a function of curing an epoxy resin. For example, a phenolic curing agent, a naphthol curing agent, an active ester curing agent, a benzoxazine curing agent, a cyanate ester curing agent, and a carbodiimide. System curing agent and the like. A hardening | curing agent may be used individually by 1 type, and may be used in combination of 2 or more type.

  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. Among 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 alone or in combination of two or more.

  Specific examples of the phenol-based curing agent and the naphthol-based curing agent include, for example, “MEH-7700”, “MEH-7810”, “MEH-7785” manufactured by Meiwa Kasei Co., Ltd., and Nippon Kayaku Co., Ltd. “NHN”, “CBN”, “GPH”, “SN-170”, “SN-180”, “SN-190”, “SN-475”, “SN-485”, “Tohto Kasei Co., Ltd.” SN-495 "," SN-375 "," SN-395 "," LA-7052, "" LA-7054, "" LA-3018, "" LA-1356, "etc. manufactured by DIC Corporation. .

  From the viewpoint of increasing the adhesion strength with the conductor layer 24, an active ester curing agent is also preferable. Although there is no restriction | limiting in particular as an active ester type hardening | curing agent, Generally ester groups with high reaction activity, such as phenol ester, thiophenol ester, N-hydroxyamine ester, ester of heterocyclic hydroxy compound, are in 1 molecule. A compound having two or more in the above is preferably used. The active ester curing agent is preferably obtained by a condensation reaction of a carboxylic acid compound and / or a thiocarboxylic acid compound with a hydroxy compound and / or a thiol compound. In particular, from the viewpoint of improving heat resistance, an active ester curing agent obtained from a carboxylic acid compound and a hydroxy compound is preferable, and an active ester 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, and pyromellitic acid. 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, phloroglucin, benzene Examples include triol, dicyclopentadiene type diphenol compound, phenol novolac and the like. Here, the “dicyclopentadiene type diphenol compound” refers to a diphenol compound obtained by condensing two molecules of phenol with one molecule of dicyclopentadiene.

  The active ester type curing agent includes 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 benzoylated product of phenol novolac. Among them, 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 alone or in combination of two or more. The “dicyclopentadiene-type diphenol structure” represents a divalent structural unit composed of phenylene-dicyclopentalene-phenylene.

  As an active ester compound containing a dicyclopentadiene-type diphenol structure, “EXB9451”, “EXB9460”, “EXB9460S”, “HPC8000-65T” (manufactured by DIC Corporation), “EXB9416-70BK” (manufactured by DIC Corporation) as an active ester compound containing a naphthalene structure, “DC808” (manufactured by Mitsubishi Chemical Corporation) 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 to be included 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 Kasei Kogyo Co., Ltd.

  Although it does not specifically limit as a cyanate ester type hardening | curing agent, For example, novolak type (phenol novolak type, alkylphenol novolak type, etc.) cyanate ester type hardening agent, dicyclopentadiene type cyanate ester type hardening agent, bisphenol type (bisphenol A type, And bisphenol F type, bisphenol S type, and the like) and cyanate ester-based curing agents, and prepolymers in which these are partially triazines. Specific examples include bisphenol A dicyanate (also referred to as BADCy, 2,2-bis (4-cyanatephenyl) propane), polyphenol cyanate (oligo (3-methylene-1,5-phenylene cyanate)), 4, 4'-methylenebis (2,6-dimethylphenylcyanate), 4,4'-ethylidenediphenyl dicyanate, hexafluorobisphenol A dicyanate, 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 Cyanate resin, phenol novolac and Polyfunctional cyanate resin derived from resol novolac, these cyanate resins and partially triazine of prepolymer. Commercial products of cyanate ester-based curing agents include Lonza's “PT30” and “PT60” (both phenol novolac polyfunctional cyanate ester resins) and “BA230” (part or all of bisphenol A dicyanate is triazine) And a trimer prepolymer), “Primaset® BADCy” and the like.

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

  From the viewpoint of improving the mechanical strength and water resistance of the resulting insulating layer, the amount ratio of the epoxy resin and the curing agent is a ratio of [total number of epoxy groups of epoxy resin]: [total number of reactive groups of curing agent]. 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 more preferable. Here, the reactive group of the curing agent is an active hydroxyl group, an active ester group or the like, and varies depending on the type of the curing agent. Moreover, the total number of epoxy groups of the epoxy resin is a value obtained by totaling the values obtained by dividing the mass of the nonvolatile component of each epoxy resin by the epoxy equivalent for all epoxy resins, and the total number of reactive groups of the curing agent is The value obtained by dividing the mass of the non-volatile component of each curing agent by the reactive group equivalent is the total value for all curing agents.

-Inorganic filler-
The material of the inorganic filler is not particularly limited, for example, silica, alumina, glass, cordierite, silicon oxide, barium sulfate, barium carbonate, talc, clay, mica powder, zinc oxide, hydrotalcite, boehmite, Aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, magnesium oxide, boron nitride, aluminum nitride, manganese nitride, aluminum borate, strontium carbonate, zirconium oxide, barium titanate, barium zirconate titanate, strontium titanate, Examples thereof include calcium titanate, magnesium titanate, bismuth titanate, titanium oxide, barium zirconate, calcium zirconate, zirconium phosphate, and zirconium tungstate phosphate. Among these, silica such as amorphous silica, fused silica, crystalline silica, synthetic silica, and hollow silica is particularly suitable. As silica, spherical silica is preferable. An inorganic filler may be used individually by 1 type, and may be used in combination of 2 or more type. Examples of commercially available spherical fused silica include “SO-C3”, “SO-C2”, “SO-C1”, “YA100C”, “YA050C”, “YA010C” manufactured by Admatechs Co., Ltd., and the like.

  The average particle size of the inorganic filler is preferably 3 μm or less, more preferably 1 μm or less, and more preferably 0.7 μm or less from the viewpoint of obtaining an insulating layer on which a fine wiring pattern can be formed. 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 a resin varnish is formed using the resin composition. Is preferably 0.03 μm or more, more preferably 0.05 μm or more, still more preferably 0.07 μm or more, and particularly preferably 0.1 μm or more. The average particle diameter of the inorganic filler can be measured by a laser diffraction / scattering method based on Mie scattering theory. Specifically, the particle size distribution of the inorganic filler can be created on a volume basis by a laser diffraction particle size distribution measuring device, and the median diameter can be measured as the average particle diameter. 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 are 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, 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 an aminosilane coupling agent, an epoxysilane coupling agent, a mercaptosilane coupling agent, a silane coupling agent, an organosilazane compound, and a titanate coupling agent. A surface treating agent may be used individually by 1 type, and may be used in combination of 2 or more type. Examples of commercially available surface treatment agents include “KBM403” (3-glycidoxypropyltrimethoxysilane) manufactured by Shin-Etsu Chemical Co., Ltd., and “KBM803” (3-mercaptopropyltrimethoxy manufactured by Shin-Etsu Chemical Co., Ltd.). Silane), Shin-Etsu Chemical "KBE903" (3-aminopropyltriethoxysilane), Shin-Etsu Chemical "KBM573" (N-phenyl-3-aminopropyltrimethoxysilane), Shin-Etsu Chemical "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 inorganic filler after the surface treatment, followed by ultrasonic cleaning. After removing the supernatant and drying the obtained nonvolatile component, the amount of carbon bonded to the surface of the inorganic filler is measured using a carbon analyzer. By dividing the obtained amount of carbon by the specific surface area of the inorganic filler, the amount of carbon per unit surface area bonded to the inorganic filler is calculated. 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 thermal expansion coefficient 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 further preferably 60% by mass or more. In the case where the insulating layer 30 is formed using a resin composition having a high inorganic filler content, the adhesion strength between the insulating layer 30 and the conductor layer 24 may decrease, but according to the method for manufacturing a circuit board of the present invention. For example, even when a resin composition having a high content of 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 reducing 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 mass% or more, 64 mass% or more, 66 mass% or more, 68 mass% or more, or 70 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 contains the above-mentioned epoxy resin, a hardening | curing agent, and an 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 liquid epoxy resin: solid epoxy resin is preferably 1: 0.1 to 1: 6, more preferably 1). : 0.3-1: 5, more preferably 1: 0.6-1: 4.5) as a curing agent, a phenolic curing agent, a naphthol curing agent, an active ester curing agent and a cyanate ester curing agent It is preferable that at least one selected from the group consisting of silica is included as an inorganic filler. Regarding the resin composition layer 30X including a combination of such specific components, the preferred content of the epoxy resin, the curing agent, and the inorganic filler is as described above, and among them, the content of the epoxy resin is 5% by mass. It is preferable that the content of the inorganic filler is 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. More preferably, it is 90 mass%. Regarding the content of the curing agent, the ratio of the total number of epoxy groups of the epoxy resin and the total number of reactive groups of the curing agent is preferably included so as to be 1: 0.2 to 1: 2. It is more preferable to make it contain from 1: 0.3 to 1: 1.5, and it is still more preferred to make it contain from 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 as 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 include ether ketone resins and polyester resins. A thermoplastic resin may be used individually by 1 type, or may be used in combination of 2 or more type.

  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 10,000 to 60000, and still more preferably in the range of 20000 to 60000. The weight average molecular weight in terms of polystyrene of the thermoplastic resin is measured by a gel permeation chromatography (GPC) method. Specifically, the polystyrene-converted weight average molecular weight of the thermoplastic resin is LC-9A / RID-6A manufactured by Shimadzu Corporation as a measuring device, and Shodex K-800P / K- manufactured by Showa Denko KK as a column. 804L / K-804L can be measured by using chloroform or the like as a mobile phase and a column temperature of 40 ° C., and using a standard polystyrene calibration curve.

  Examples of the phenoxy resin include bisphenol A skeleton, bisphenol F skeleton, bisphenol S skeleton, bisphenolacetophenone skeleton, novolac skeleton, biphenyl skeleton, fluorene skeleton, dicyclopentadiene skeleton, norbornene skeleton, naphthalene skeleton, anthracene skeleton, adamantane skeleton, terpene Examples thereof include phenoxy resins having a skeleton and one or more skeletons selected from the group consisting of a trimethylcyclohexane skeleton. The terminal of the phenoxy resin may be any functional group such as a phenolic hydroxyl group or an epoxy group. A phenoxy resin may be used individually by 1 type, and may be used in combination of 2 or more type. 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). In addition, "FX280" and "FX293" manufactured by Toto Kasei Co., Ltd., "YX7553", "YX7553BH30", "YL6794", "Mitsubishi Chemical Co., Ltd." YL7213 "," YL7290 "," YL7482 ", etc. are mentioned.

  Specific examples of the polyvinyl acetal resin include electric butyral 4000-2, 5000-A, 6000-C, and 6000-EP manufactured by Denki Kagaku Kogyo Co., Ltd., and ESREC BH series and BX series manufactured by Sekisui Chemical Co., Ltd. KS series, BL series, BM series, etc. are mentioned.

  Specific examples of the polyimide resin include “Rika Coat SN20” and “Rika Coat PN20” manufactured by Shin Nippon Rika 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, a linear polyimide described in JP-A-2006-37083). And modified polyimides such as polysiloxane skeleton-containing polyimide (polysiloxane skeleton-containing polyimide described in JP-A No. 2002-12667 and JP-A No. 2000-319386).

  Specific examples of the polyamide-imide resin include “Bilomax HR11NN” and “Bilomax HR16NN” manufactured by Toyobo Co., Ltd. Specific examples of the polyamideimide resin also include modified polyamideimides such as polysiloxane skeleton-containing polyamideimides “KS9100” and “KS9300” manufactured by Hitachi Chemical Co., Ltd.

  Specific examples of the polyethersulfone resin include “PES5003P” manufactured by Sumitomo Chemical Co., Ltd.

  Specific examples of the polysulfone resin include polysulfone “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.

-Curing accelerator-
Examples of the curing accelerator include phosphorus-based curing accelerators, amine-based curing accelerators, imidazole-based curing accelerators, guanidine-based curing accelerators, phosphorus-based curing accelerators, amine-based curing accelerators, and imidazole-based accelerators. A curing accelerator is preferred. A hardening accelerator may be used individually by 1 type, and may be used in combination of 2 or more type. The content of the curing accelerator is preferably used in the range of 0.05% by mass to 3% by mass when the total of the nonvolatile 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. A flame retardant may be used individually by 1 type, or may be used in combination of 2 or more type. 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 in forming the insulating layer of the circuit board may be used. Examples thereof include rubber particles, polyamide fine particles, and silicone particles, and rubber particles are preferable.

  The rubber particle is not particularly limited as long as it is a fine particle of a resin that has been subjected to a chemical crosslinking treatment on a resin exhibiting rubber elasticity and is insoluble and infusible in an organic solvent. For example, acrylonitrile butadiene rubber particles, butadiene rubber particles, Examples include acrylic rubber particles. Specific examples of the rubber particles include XER-91 (manufactured by Nippon Synthetic Rubber Co., Ltd.), Staphyloid AC3355, AC3816, AC3816N, AC3832, AC4030, AC3364, IM101 (above, manufactured by Aika Industry Co., Ltd.), paraloid. EXL2655, EXL2602 (above, Kureha Chemical Industry Co., Ltd.) and the like.

  The average particle diameter 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 diameter 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 measured by making the median diameter as an average particle diameter. 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 as necessary. Examples of other components include organometallic compounds such as organocopper compounds, organozinc compounds, and organocobalt compounds, and thickeners, antifoaming agents, leveling agents, adhesion imparting agents, colorants, and curable resins. Examples thereof include resin additives.

  In the resin sheet 60 with a plastic film support, the resin composition layer 30X may have a multilayer structure including two or more layers. When setting it as the resin composition layer 30X of a multilayer structure, it is preferable that the whole thickness exists in the said range.

  The resin sheet 60 with a plastic film support can be manufactured by forming the resin composition layer 30 </ b> X 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 obtain a resin composition. Layer 30X can be formed.

  Solvents used for preparing the resin varnish include, for example, ketone solvents such as acetone, methyl ethyl ketone and cyclohexanone, acetate solvents such as ethyl acetate, butyl acetate, cellosolve acetate, propylene glycol monomethyl ether acetate and carbitol acetate, 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. A solvent may be used individually by 1 type and may be used in combination of 2 or more type.

  The coating film may be dried by a known drying method such as heating or hot air blowing. If a large amount of solvent remains in the resin composition layer 30X, it may cause swelling after curing, so that the residual solvent amount in the resin composition is usually 10% by mass or less, preferably 5% by mass or less. Let Depending 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 minutes to 10 minutes. Layer 30X can be formed.

  In the resin sheet 60 with a plastic film support, the surface of the resin composition layer 30X that is not joined to the plastic film support 50 (that is, the surface opposite to the plastic film support 50) has a 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 1 μm to 40 μm, for example. By laminating the protective film, it is possible to prevent adhesion or scratches of dust or the like to the surface of the resin composition layer 30X. The resin sheet 60 with a plastic film support can be wound and stored in a roll shape, and can be used by peeling off the protective film when the circuit board 10 is manufactured.

[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, for example, a semiconductor device including the circuit board 10 can be manufactured.

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

  EXAMPLES The present invention will be specifically described with reference to examples, but the present invention is not limited to these examples. In the following, “part” and “%” mean “part by mass” and “% by mass”, respectively, unless otherwise specified.

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

[Sample preparation and evaluation]
(1) Substrate treatment of wiring board Glass cloth base epoxy resin laminate with a circular conductor pattern (wiring pattern) with a diameter of 150 μm on both sides (copper foil thickness 18 μm, substrate thickness 0.3 mm, size Treatment (i) “CZ8100” manufactured by MEC Co., Ltd. on both sides of a conductive pattern (wiring board having a copper ratio of about 70%) using “R5715ES” manufactured by Panasonic Corporation, 510 mm × 340 mm A sample (i) obtained by etching the surface of the conductor pattern after removing it by etching to a thickness of about 0.6 μm, and a treatment (ii) instead of the treatment (i) (me) on the surface of the conductor pattern ( A sample (ii) obtained by performing “Flatbond” treatment manufactured by Co., Ltd. was prepared.

(Measurement of arithmetic average roughness (Ra value) of the surface of the conductor layer)
Using a non-contact type surface roughness meter (BYCO Instruments WYKO NT3300), Ra value was obtained as a numerical value obtained with a measurement range of 121 μm × 92 μm by a VSI contact mode and a 50 × lens. In addition, Ra value is a value obtained by calculating | requiring the average value of 10 measured values of each of sample (i) and sample (ii). The Ra value of sample (i) treated with CZ8100 was 270 nm, and the Ra value of sample (ii) subjected to flat bond treatment was 160 nm. Thus, in this embodiment, the Ra value is made smaller than the Ra value (500 nm to 700 nm) obtained by the conventional process (etching to a thickness of about 1 μm to 2 μm).

(2) Lamination process of resin sheet with plastic film support The protective film of a resin sheet with a plastic film support (prepreg with a plastic film support) (size 504 mm x 334 mm) prepared as shown in the following production example is peeled off Then, using a batch type vacuum pressure 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 board treated in (1) above. Laminated on both sides of the substrate. This lamination process was carried out by reducing the pressure for 30 seconds to a pressure of 13 hPa or less and then pressing the film for 30 seconds under conditions of a temperature of 110 ° C. and a pressure of 0.74 MPa. Next, a hot pressing process was performed for 60 seconds under 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 the prepreg with a plastic film support is bonded to both sides of the wiring board, the laminating step is decompressed for 30 seconds to reduce the pressure to 13 hPa or less. This was carried out by pressing for 60 seconds under the conditions of a temperature of 120 ° C. and a pressure of 0.74 MPa. Next, a hot pressing process was performed for 90 seconds under 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) Ground treatment of copper foil The glossy surface side of 3EC-III (electrolytic copper foil, thickness 35 μm) manufactured by Mitsui Mining & Mining Co., Ltd. is made thick with “CZ8100” manufactured by Mec Co., Ltd. The sample (i) obtained by etching and removing the copper foil surface by 0.6 μm, and the treatment (ii) in place of the treatment (i) (ii) “Flatbond” treatment manufactured by MEC Thus, a sample (ii) obtained by treating the surface of the copper foil was prepared. The roughness of the copper foil surface was Ra value 270 (nm) for sample (i) treated with CZ8100, and Ra value 160 (nm) for sample (ii) subjected to flat bond treatment. It was.

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

(C) Measurement of peel strength (peel strength) of conductor layer Evaluation substrate A obtained in the above (b) was cut into small pieces of 150 mm × 30 mm. A strip-shaped cut with a width of 10 mm and a length of 100 mm is made in the copper foil portion of the small piece, and one end of the strip-shaped cut of the copper foil is peeled off to grasp a grip (TSE Co., Ltd., Autocom type) Measure with a test machine AC-50C-SL) and measure the load when peeling 35mm perpendicularly to the surface of the evaluation board A at a speed of 50 mm / min at room temperature using an Instron universal tester. 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 peel strength of less than 0.15 kgf / cm was evaluated as “x”.

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

(3) Curing of resin composition layer A wiring board on which a resin sheet with a plastic film support was laminated was 120 ° C for 30 minutes, then 175 ° C for 30 minutes, or 165 ° C for 30 minutes (Comparative Examples 1 and 2). The resin composition layer was cured by heating to form an insulating layer.

(4) Formation of via hole A laser beam was irradiated from above 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.

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

  Example 1, Comparative Example 1 and Comparative Example 3 are according to the procedure (A) below, Example 2 and Example 4 are according to the procedure (B) below, and Example 3 and Comparative Example 4 are the following (C ), A small-sized via hole was formed in each insulating layer according to the following procedure (D) for Comparative Example 2.

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

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

(5) Desmear treatment After forming the via hole, the plastic film support was peeled off, and the desmear treatment was performed on the circuit board provided with the via hole. In addition, as a desmear process, the following wet desmear process was implemented.
Wet desmear treatment:
A circuit board provided with a via hole is 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 of potassium permanganate concentration of about 6% and sodium hydroxide concentration of about 4%) at 80 ° C. for 20 minutes, and finally neutralization solution (Atotech Japan Co., Ltd.) ) “Reduction Solution Securigant P”, sulfuric acid aqueous solution) for 5 minutes at 40 ° C. and then dried at 80 ° C. for 15 minutes. The obtained substrate is referred to as “evaluation substrate B”.

(6) Confirmation of via hole shape With respect to the evaluation substrate B obtained in (5) above, the opening of the via hole was scanned from the surface to a scanning electron microscope (SMI3050SE FIB-SEM composite device manufactured by SII NanoTechnology Co., Ltd.). Then, the central cross section is cut out with a focused ion beam processing observation apparatus (FIB), and the top diameter (Z) of the via hole, the minimum diameter of the via hole (Y), the bottom diameter of the via hole (X ) And the distance from the bottom of the via hole having the minimum diameter (Y), and the average value of 10 via holes was obtained.

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

1. Alkali cleaning (cleaning and charge adjustment of the surface of the insulating layer with via holes)
Product name: Cleaned at 60 ° C. for 5 minutes using Cleaning Cleaner Security 902 (trade name).
2. Soft etching (cleaning inside via holes)
The mixture was treated with an aqueous sodium peroxodisulfate solution at 30 ° C. for 1 minute.
3. Pre-dip (adjustment of surface charge of insulating layer for Pd application)
Pre. Using Dip Neoganth B (trade name), it was treated at room temperature for 1 minute.
4). Activator application (Pd application to the surface of the insulating layer)
Using Activator Neoganth 834 (trade name), it was treated at 35 ° C. for 5 minutes.
5. Reduction (reduction of Pd applied to the insulating layer)
Reducer Neoganth WA (trade name) and Reducer Accelerator 810 mod. Using a mixed solution with (trade name), it was treated at 30 ° C. for 5 minutes.
6). Electroless copper plating process (Cu is deposited on the surface of the insulating layer (Pd surface))
Using a mixture of Basic Solution Print MSK-DK (trade name), Copper solution Print MS MS (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 process Subsequently, the electrolytic copper plating process was performed on condition that copper is filled in the via hole using a chemical solution manufactured by Atotech Japan Co., Ltd. Thereafter, 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 the land pattern. did. Next, annealing 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>
For the evaluation substrate C obtained in (7) above, using a small thermal shock device “TSE-11” manufactured by Espec Co., Ltd., treatment a at −55 ° C. for 30 minutes and 120 ° C. for 30 minutes. A thermal cycle test (TCB) was performed in which the treatment b was performed continuously for 1000 cycles. Then, after observing the filled via composed of copper filled in the via hole by the above plating process from the surface with a scanning electron microscope (SMI3050SE FIB-SEM composite device manufactured by SII NanoTechnology Co., Ltd.), the FIB Then, the cross section of the central part was cut out, and cracks in the insulating layer and the conductor layer and voids in the conductor layer were observed with respect to 10 filled vias, and evaluated according to the following evaluation criteria.
Evaluation criteria:
○: No cracks or voids were confirmed for 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 of about 165, "ZX1059" manufactured by Nippon Steel & Sumikin Chemical Co., Ltd., 1: 1 mixture of bisphenol A type and bisphenol F type), xylenol Type epoxy resin (epoxy equivalent of about 185, "YX4000HK" manufactured by Mitsubishi Chemical Corporation), 10 parts of biphenyl type epoxy resin (epoxy equivalent of about 290, "NC3000H" manufactured by Nippon Kayaku Co., Ltd.), and phenoxy resin ( “YX7553BH30” manufactured by Mitsubishi Chemical Corporation, 10 parts of a methyl ethyl ketone (MEK) solution containing 30% by mass of nonvolatile components was dissolved in 20 parts of solvent naphtha with stirring. After cooling to room temperature, 10 parts of a triazine skeleton-containing phenol novolac curing agent (hydroxyl equivalent 146, “LA-1356” manufactured by DIC Corporation, MEK solution with a nonvolatile component of 60% by mass), active ester curing 10 parts of an agent (DIC Corporation "HPC8000-65T", active group equivalent of about 223, non-volatile component 65% by mass toluene solution), curing accelerator (4-dimethylaminopyridine (DMAP), non-volatile component 2% by mass) MEK solution) 4 parts, flame retardant (“HCA-HQ”, Sanko Co., Ltd., 10- (2,5-dihydroxyphenyl) -10-hydro-9-oxa-10-phosphaphenanthrene-10-oxide , 2 parts of average particle size), 2 parts of rubber particles ("STAPHYLOID AC3816N" manufactured by Aika Industry Co., Ltd., finely pulverized product), aminosilane-based coupling Small-diameter spherical silica (“SO-C1” manufactured by Admatechs Co., Ltd.), average particle diameter, which has been surface-treated with a coating agent (“KBM573” manufactured by Shin-Etsu Chemical Co., Ltd.), and particles of 3 μm or more removed by classification. Resin varnish 1 was prepared by mixing 100 parts of 0.25 μm and carbon amount per unit surface area of 0.36 mg / m ² ) and uniformly dispersing with a high-speed rotary mixer. Table 1 shows the components and amounts of the resin varnish 1.

<Preparation Example 2> Preparation of resin varnish 2 6 parts of bisphenol type epoxy resin (epoxy equivalent of about 165, "ZX1059" manufactured by Nippon Steel & Sumikin Chemical Co., Ltd., 1: 1 mixture of bisphenol A type and bisphenol F type), naphthalene type 3 parts of epoxy resin (“HP-4032SS” manufactured by DIC Corporation, epoxy equivalent of about 144), 9 parts of bixylenol type epoxy resin (epoxy equivalent of about 185, “YX4000HK” manufactured by Mitsubishi Chemical Corporation), biphenyl type epoxy resin (Epoxy equivalent of about 290, Nippon Kayaku Co., Ltd. “NC3000H”) 8 parts, and phenoxy resin (Mitsubishi Chemical Co., Ltd. “YX7553BH30”, methyl ethyl ketone (MEK) solution of 30% by mass of nonvolatile components), The solution was dissolved 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 Corporation, active group equivalent of about 223, 65% by weight non-volatile component in toluene), a curing accelerator (4 -10 parts of dimethylaminopyridine (DMAP), MEK solution containing 2% by mass of non-volatile components, flame retardant ("HCA-HQ" manufactured by Sanko Co., Ltd.), 10- (2,5-dihydroxyphenyl) -10-hydro-9 -2 parts of oxa-10-phosphaphenanthrene-10-oxide, average particle size 1 μm, 2 parts of rubber particles (“STAPHYLOID AC3816N”, finely pulverized product manufactured by Aika Kogyo Co., Ltd.), aminosilane coupling agent (Shin-Etsu Chemical Co., Ltd. “KBM573”) surface-treated, small diameter spherical silica from which particles of 3 μm or more have been removed by classification (Admatex Co., Ltd.) 100 parts of “SO-C1” manufactured, average particle diameter of 0.25 μm, carbon amount per unit surface area of 0.36 mg / m ² ) were mixed and uniformly dispersed with a high-speed rotary mixer to prepare a resin varnish 2. Table 1 shows the components and amounts of resin varnish 2.

<Preparation Example 3> Preparation of resin varnish 3 2 parts of bisphenol type epoxy resin (epoxy equivalent of about 165, "ZX1059" manufactured by Nippon Steel & Sumikin Chemical Co., Ltd., 1: 1 mixture of bisphenol A type and bisphenol F type), bixylenol Type epoxy resin (epoxy equivalent of about 185, "YX4000HK" manufactured by Mitsubishi Chemical Corporation), 12 parts of biphenyl type epoxy resin (epoxy equivalent of about 290, "NC3000H" manufactured by Nippon Kayaku Co., Ltd.), and phenoxy resin ( “YX7553BH30” manufactured by Mitsubishi Chemical Corporation, 10 parts of a methyl ethyl ketone (MEK) solution containing 30% by mass of nonvolatile components was dissolved in 20 parts of solvent naphtha with stirring. After cooling to room temperature, 10 parts of an active ester curing agent (“HPC8000-65T” manufactured by DIC Corporation, a toluene solution having an active group equivalent of about 223 and a nonvolatile component of 65% by mass), a cyanate ester curing agent (BADCy, "Primase (registered trademark) BADCy" manufactured by Lonza) 5 parts, curing accelerator (4-dimethylaminopyridine (DMAP), MEK solution containing 2% by mass of non-volatile components), curing accelerator (Tokyo Kasei ( Co., Ltd., Cobalt (III) acetylacetonate (Co (III) -1M), 2 parts of MEK solution containing 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-phosphaphenanthrene-10-oxide, average particle size 1 μm), 2 parts, rubber particles ( It is surface-treated with 2 parts of “STAPHYLOID AC3816N”, finely pulverized product manufactured by Ika Kogyo Co., Ltd., and an aminosilane coupling agent (“KBM573” manufactured by Shin-Etsu Chemical Co., Ltd.). 100 parts of the removed small-diameter spherical silica ("SO-C1" manufactured by Admatechs Co., Ltd., average particle size of 0.25 µm, carbon amount per unit surface area of 0.36 mg / m ² ) are mixed and uniformly mixed with a high-speed rotary mixer The resin varnish 3 was prepared. Table 1 shows the components and amounts of resin varnish 3.

<Production Example 1> Production of resin sheet 1 with plastic film support PET film (Toray Industries, Inc.) as a plastic film support was subjected to a release treatment with a non-silicone release agent (“AL-5” manufactured by Lintec Corporation). ) “Lumirror T6AM” (thickness: 38 μm) was prepared. The 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, a rough side of a polypropylene film (“Alphan MA-411” manufactured by Oji Specialty Paper Co., Ltd., thickness: 15 μm) is attached as a protective film to the surface of the resin composition layer that is not bonded to the plastic film support. In addition, a resin sheet 1 with a plastic film support (resin sheet 1) was obtained.

<Preparation Example 2> Preparation of Prepreg 2 with Plastic Film Support Substrate 1000 glass cloth (thickness 14 μm) manufactured by Arisawa Manufacturing Co., Ltd. is immersed and impregnated in the resin varnish 1 by a solvent method, and the solvent is volatilized by heating. , Dried 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 Corporation) PET film ("Lumirror T6AM" manufactured by Toray Industries, Inc., 38 μm thick) and polypropylene film (“Alphan MA-411” manufactured by Oji Specialty Paper Co., Ltd., 15 μm thick). The rough surface side of was attached, and the prepreg 2 with a plastic film support body (prepreg 2) was obtained.

Production Example 3 Production of Resin Sheet 3 with Plastic Film Support As a plastic film support, a PET film (Toray Industries, Inc.) subjected to release treatment with a non-silicone release agent (“AL-5” manufactured by Lintec Corporation). ) “Lumirror T6AM” (thickness: 38 μm) was prepared. The 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, a rough side of a polypropylene film (“Alphan MA-411” manufactured by Oji Specialty Paper Co., Ltd., thickness: 15 μm) is attached as a protective film to 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 PET film (Toray Industries, Inc.) as a plastic film support was subjected to release treatment with a non-silicone mold release agent ("AL-5" manufactured by Lintec Corporation). ) “Lumirror T6AM” (thickness: 38 μm) was prepared. The 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, a rough side of a polypropylene film (“Alphan MA-411” manufactured by Oji Specialty Paper Co., Ltd., thickness: 15 μm) is attached as a protective film to 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.

<Preparation Example 5> Preparation of Prepreg 5 with Plastic Film Support Substrate 1000 glass cloth (thickness 14 μm) manufactured by Arisawa Manufacturing Co., Ltd. is immersed in resin varnish 3 by the solvent method, and the solvent is volatilized by heating. 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 Corporation) from both sides. The release surface of the release-treated PET film (“Lumirror T6AM” manufactured by Toray Industries, Inc., thickness 38 μm) and the polypropylene film (“Alphan MA-411” manufactured by Oji Specialty Paper Co., Ltd., thickness 15 μm) The rough surface side was bonded together to obtain a prepreg 5 with a plastic film support (prepreg 5).

  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 a contact-type thickness gauge ) Measured using Mitutoyo MCD-25MJ).

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

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

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

  A sample according to Example 4 was prepared in the same manner as 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 step (3) was heated at 165 ° C. for 30 minutes, and the resin composition layer was thermally cured to form an insulating layer. .

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

  A 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 a plastic film support.

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

  The preparation conditions, aspects and evaluation results of the samples according to Examples 1 to 4 are shown in Table 2 below, and the preparation conditions, aspects and evaluation results of the samples according to 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, It has been clarified by a thermal cycle test that even when a small-diameter via hole 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 over time can be suppressed, reliability can be improved, product life can be extended, and a thin circuit board can be provided. .

DESCRIPTION OF SYMBOLS 10 Circuit board 20 Wiring board 22 Board | substrate 24 Conductor layer 24a The surface of a conductor layer 30 Insulating layer 30X Resin composition layer 30a The surface of an insulating layer 40 Via hole 42 Bending part 44 Bottom part 50 Plastic film support 60 Resin sheet | seat with a plastic film support 70 Wiring layer X Bottom diameter Y Minimum diameter Z Top diameter t Insulation layer thickness d Via hole depth

Claims (20)

A circuit board comprising a conductor layer and an insulating layer covering the conductor layer, and a via hole exposing a part of the conductor layer from the insulating layer;
The arithmetic average roughness of the surface of the conductor layer is 350 nm or less,
The via hole has a depth of 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).   The circuit board according to claim 1, wherein the position of the minimum diameter is located closer to the conductor layer when the depth of the via hole is used as a reference.   The circuit board according to claim 1, wherein the arithmetic average roughness of the surface of the conductor layer is 300 nm or less.   The circuit board according to claim 1, wherein a depth of the via hole is 25 μm or less.   The circuit board according to any one of claims 1 to 4, wherein an adhesion strength between the conductor layer and the insulating layer is 0.15 kgf / cm or more.   The circuit board according to claim 1, wherein an adhesion strength between the conductor layer and the insulating layer is 0.2 kgf / cm or more.   The circuit board according to claim 1, wherein a top diameter (Z) of the via hole is 40 μm or less.   The circuit board according to claim 1, wherein the insulating layer is a cured product of a resin composition.   The circuit board according to claim 1, wherein the via hole is a via hole formed by irradiating a laser.   A semiconductor device comprising the circuit board according to claim 1. Step (A) A resin sheet with a plastic film support comprising a plastic film support and a resin composition layer bonded to the plastic film support, and a conductor pattern having a surface arithmetic mean roughness of 350 nm or less A step of bonding to the conductive layer of the wiring board provided with the conductive layer,
Step (B) The resin composition layer is heat-cured to provide an insulating layer having a thickness on the conductor layer of 30 μm or less, and an adhesion strength between the insulating layer and the conductor layer is 0.15 kgf / cm or more Forming an insulating layer,
Step (C) A laser is irradiated from the plastic film support side to form a via hole having a top diameter (Z) of 50 μm or less on the insulating layer, the top diameter (Z) of the via hole and the minimum diameter (Y ) And the bottom diameter (X) of the via hole, the step of forming the via hole satisfying Y / Z = 0.7 to 0.99 and Y / X = 0.7 to 1 (Z>Y); ,
Step (D) performing a desmear process;
Step (E) peeling the plastic film support from the insulating layer;
And (F) forming a further conductor layer on the insulating layer.   The circuit board according to claim 11, wherein, in the step (C), the via hole is formed such that a position of a minimum diameter (Y) is located closer to the conductor layer when the depth of the via hole is used as a reference. Manufacturing method.   The method for manufacturing a circuit board according to claim 11 or 12, wherein the desmear process in the step (D) is a wet desmear process.   The process (F) is a process of forming a metal layer by dry plating on the surface of the insulating layer and forming the conductor layer by wet plating on the surface of the metal layer. The manufacturing method of the circuit board as described in a term.   The method for manufacturing a circuit board according to claim 11, wherein the plastic film support is a plastic film support with a release layer.   The method for manufacturing a circuit board according to claim 11, wherein the resin composition layer includes an epoxy resin, a curing agent, and an inorganic filler.   The method for manufacturing a circuit board according to claim 16, wherein an average particle diameter of the inorganic filler is 0.01 μm to 3 μm.   The method for manufacturing a circuit board according to claim 16, wherein the inorganic filler has an average particle diameter of 0.01 μm to 0.4 μm.   The content of the inorganic filler in the resin composition layer is 40% by mass to 95% by mass when the nonvolatile component in the resin composition layer is 100% by mass. A method for manufacturing a circuit board according to claim 1.   The method for manufacturing a circuit board according to claim 16, wherein the inorganic filler is surface-treated with a surface treatment agent.

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