JPWO2019240217A1 - Manufacturing method of laminated film and laminated structure - Google Patents

Abstract

Provided is a laminated film capable of suppressing natural peeling of the base film from the insulating resin layer at the time of curing and suppressing poor peeling of the base film when the base film is peeled from the insulating resin layer after curing. To do. The laminated film according to the present invention includes a base film and an insulating resin layer laminated on the surface of the base film, and the base material is provided on one end side of the laminated film with respect to the end face of the insulating resin layer. When the end face of the film protrudes most outward, the peeling strength of the base film with respect to the insulating resin layer is Xgf / cm, and the protruding distance of the base film on one end side is Y mm, Y / X is 0.5 or more and 15 or less.

Description

The present invention relates to a laminated film including a base film and an insulating resin layer. The present invention also relates to a method for manufacturing a laminated structure using the above-mentioned laminated film.

Conventionally, various resin compositions have been used to obtain electronic components such as semiconductor devices, laminated boards and printed wiring boards. For example, in a multilayer printed wiring board, a resin composition is used to form an insulating layer for insulating the inner layers and to form an insulating layer located on a surface layer portion. In order to form the insulating layer, a laminated film including a base film and an insulating resin layer is used. The insulating resin layer is obtained by forming the resin composition into a film.

In the manufacturing method of a multilayer printed wiring board or the like, an insulating layer (cured product layer or pre-cured product layer) is formed by curing or pre-curing the insulating resin layer in a state where the base film and the insulating resin layer are laminated. After that, the base film may be peeled off from the cured or pre-cured insulating resin layer.

An example of such a manufacturing method is described in Patent Documents 1 and 2 below.

In Patent Document 1 below, a blind via having a top diameter of 100 μm or less is obtained by irradiating the insulating layer with a carbon dioxide gas laser from above the plastic film in a state where the insulating layer and the plastic film are laminated on both sides or one side of the circuit board. A method for manufacturing a multilayer printed wiring board including a step of forming the above-mentioned is disclosed. The insulating layer contains 35% by mass or more of an inorganic filler.

Patent Document 2 below discloses a method for manufacturing a circuit board including the following steps (A) to (F). (A) A step of laminating a resin sheet with a support including a plastic film support and a resin composition layer to be bonded to the plastic film support on the inner layer substrate so that the resin composition layer is bonded to the inner layer substrate. .. (B) A step of thermosetting the resin composition layer to form an insulating layer, wherein the adhesive strength between the insulating layer and the plastic film support is 2 gf / cm to 18 gf / cm. (C) A step of irradiating a laser from above a plastic film support to form a via hole having a top diameter of 40 μm or less in the insulating layer. (D) A step of performing desmear processing. (E) A step of peeling off the plastic film support. (F) A step of forming a conductor layer on the surface of the insulating layer.

WO2009 / 066759A1 JP-A-2015-211085

In the conventional laminated film (laminated film including a base film and an insulating resin layer) as described in Patent Documents 1 and 2, the insulating resin layer is cured in a state where the base film and the insulating resin layer are laminated. When the film is cured, the base film may spontaneously peel off from the insulating resin layer. When the natural peeling occurs, the insulating resin layer may have uneven curing. Further, in the conventional laminated film as described in Patent Documents 1 and 2, when the base film is peeled from the insulating resin layer after curing, the base film and the insulating resin layer cannot be peeled off well, and the base material cannot be peeled off well. The film may tear.

An object of the present invention is to suppress natural peeling of the base film from the insulating resin layer during curing, and to suppress poor peeling of the base film when the base film is peeled from the insulating resin layer after curing. Is to provide a laminated film capable of producing. Another object of the present invention is to provide a method for manufacturing a laminated structure using the above-mentioned laminated film.

According to a broad aspect of the present invention, the base film and the insulating resin layer laminated on the surface of the base film are provided, and the base film is provided on one end side of the laminated film with respect to the end face of the insulating resin layer. When the end face of the material film protrudes most outward, the peeling strength of the base film with respect to the insulating resin layer is Xgf / cm, and the protruding distance of the base film on one end side is Y mm. A laminated film having a Y / X of 0.5 or more and 15 or less is provided.

In a specific aspect of the laminated film according to the present invention, the X is 0.3 or more and 9 or less.

In a specific aspect of the laminated film according to the present invention, the Y is 0.5 or more and 20 or less.

In a specific aspect of the laminated film according to the present invention, the thickness of the base film is 25 μm or more.

In a specific aspect of the laminated film according to the present invention, the arithmetic mean roughness Ra of the surface of the base film on the insulating resin layer side is 5 nm or more and less than 400 nm.

In certain aspects of the laminated film according to the present invention, the insulating resin layer comprises an epoxy compound, an inorganic filler and a curing agent.

In certain aspects of the laminated film according to the invention, the curing agent comprises a phenolic compound, a cyanate compound, a maleimide compound, or an active ester compound.

In a specific aspect of the laminated film according to the present invention, the end faces of the base film and the insulating resin layer are aligned on the other end side opposite to the one end of the laminated film, or the one end of the laminated film is aligned. On both the side and the other end side opposite to the one end, the end face of the base film protrudes outward with respect to the end face of the insulating resin layer, and the base film protrudes on the other end side. The distance is smaller than the protruding distance of the base film on one end side.

In a specific aspect of the laminated film according to the present invention, the minimum melt viscosity of the insulating resin layer in the temperature range of 60 ° C. or higher and 180 ° C. or lower is 5 mPa · s or more.

In certain aspects of the laminated film according to the present invention, the insulating resin layer is suitably used for forming an insulating layer in a multilayer printed wiring board.

According to a broad aspect of the present invention, in a state where the base film and the insulating resin layer are laminated by using the above-mentioned laminated film, the surface of the insulating resin layer on the opposite side of the base film is surfaced. In the laminating step of laminating on a member to be laminated having a metal layer on the surface, and in a state where the base film and the insulating resin layer are laminated, the insulating resin layer is irradiated with a laser from the base film side. , A method for manufacturing a laminated structure including a via hole forming step for forming a via hole is provided.

In a specific aspect of the method for manufacturing a laminated structure according to the present invention, a curing step of curing the insulating resin layer is provided between the laminating step and the via hole forming step.

The laminated film according to the present invention includes a base film and an insulating resin layer laminated on the surface of the base film. In the laminated film according to the present invention, on one end side of the laminated film, the end face of the base film protrudes most outward from the end face of the insulating resin layer. In the laminated film according to the present invention, Y / X is 0 when the peel strength of the base film with respect to the insulating resin layer is Xgf / cm and the protruding distance of the base film on one end side is Y mm. It is 5.5 or more and 15 or less. Since the laminated film according to the present invention has the above configuration, it is possible to suppress the natural peeling of the base film from the insulating resin layer during curing, and the base film is peeled from the insulating resin layer after curing. When doing so, it is possible to suppress poor peeling of the base film.

FIG. 1 is a cross-sectional view showing a laminated film according to the first embodiment of the present invention. FIG. 2 is a cross-sectional view showing a laminated film according to a second embodiment of the present invention.

Hereinafter, the present invention will be described in detail.

The laminated film according to the present invention includes a base film and an insulating resin layer laminated on the surface of the base film.

The laminated film according to the present invention has the following configuration (0).

(0) On one end side of the laminated film, the end face of the base film protrudes most outward from the end face of the insulating resin layer. (Hereinafter, it may be referred to as a laminated film (0))

In the laminated film according to the present invention, the protrusion distance on one end side is the largest among all the ends.

In the laminated film according to the present invention, when the peel strength of the base film with respect to the insulating resin layer is Xgf / cm and the protruding distance of the base film on one end side is Y mm, Y / X (Y). (Ratio to X) is 0.5 or more and 15 or less.

In the laminated film according to the present invention, the protrusion distance on one end side is the largest among all the ends, so the distance Y is the distance that protrudes the largest.

Since the laminated film according to the present invention has the above configuration, it is possible to suppress the natural peeling of the base film from the insulating resin layer during curing, and the base film is peeled from the insulating resin layer after curing. When doing so, it is possible to suppress poor peeling of the base film. In the laminated film according to the present invention, tearing of the base film can be suppressed when the base film is peeled from the insulating resin layer after curing.

It should be noted that the above-mentioned curing and the above-mentioned curing include the time of pre-curing and the post-curing.

In the laminated film according to the present invention, since one end side of the base film protrudes, the base film can be peeled from the insulating resin layer from one end side after curing.

Since the laminated film according to the present invention has the above configuration, it is possible to suppress natural peeling of the base film from the insulating resin layer during pre-curing, and the base film is formed into an insulating resin layer after pre-curing. It is also possible to suppress poor peeling of the base film when peeling from.

Further, since the laminated film according to the present invention has the above-mentioned configuration, it is possible to suppress natural peeling of the base film from the insulating resin layer during transportation of the substrate or laser irradiation for forming a via hole. Can be done.

Examples of the configuration included in the above configuration (0) include the following configuration (1), the following configuration (2), and the like. The laminated film according to the present invention may have the following configuration (1) or the following configuration (2). The laminated film according to the present invention may have the following configuration (1) or may have the following configuration (2).

(1) On one end side of the laminated film, the end face of the base film protrudes most outward from the end face of the insulating resin layer. The end faces of the base film and the insulating resin layer are aligned on the other end side of the laminated film opposite to the one end. (Hereinafter, it may be referred to as a laminated film (1))

(2) On one end side of the laminated film, the end face of the base film protrudes most outward from the end face of the insulating resin layer. On the other end side opposite to the one end of the laminated film, the end face of the base film protrudes outward with respect to the end face of the insulating resin layer. The protruding distance of the base film on the other end side is equal to or less than the protruding distance of the base film on the one end side. (Hereinafter, it may be referred to as a laminated film (2))

The one end and the other end are both ends facing each other in the laminated film.

In the configuration (2), the protruding distance of the base film on the other end side is the same as the protruding distance of the base film on the one end side, or the base film on the one end side. It is smaller than the protruding distance.

When the end faces of the base film and the insulating resin layer are aligned at all the edges of the laminated film, that is, in the case of the conventional laminated film, the base film is likely to spontaneously peel off from the insulating resin layer at the time of curing. Further, in the case of the conventional laminated film, the base film is likely to be torn when the base film is peeled from the insulating resin layer after curing. Therefore, in the conventional laminated film, it is possible to suppress the natural peeling of the base film from the insulating resin layer at the time of curing and to suppress the tearing of the base film when the base film is peeled from the insulating resin layer after curing. Have difficulty.

From the viewpoint of further suppressing the natural peeling of the base film from the insulating resin layer during curing and further suppressing the peeling failure of the base film when the base film is peeled from the insulating resin layer after curing, the laminated film. Of the (1) and the laminated film (2), the laminated film (1) is preferable.

The laminated film (2) preferably has the following configuration (2A).

(2A) On one end side of the laminated film, the end face of the base film protrudes most outward from the end face of the insulating resin layer. On the other end side opposite to the one end of the laminated film, the end face of the base film protrudes outward with respect to the end face of the insulating resin layer. The protruding distance of the base film on the other end side is smaller than the protruding distance of the base film on the one end side. (Hereinafter, it may be referred to as a laminated film (2A))

In the laminated film according to the present invention, the peel strength of the base film with respect to the insulating resin layer is Xgf / cm, and the protruding distance of the base film on one end side is Y mm. Therefore, in the laminated films (2) and (2A), the Y indicates the larger distance among the distances at which the end faces of the base film protrude outward with respect to the end faces of the insulating resin layer.

Y / X (Y X) from the viewpoint of suppressing the natural peeling of the base film from the insulating resin layer during curing and suppressing the peeling failure of the base film when the base film is peeled from the insulating resin layer after curing. Ratio to) is 0.5 or more and 15 or less. When the Y / X is less than 0.5, the base film is likely to spontaneously peel off from the insulating resin layer during curing. If the Y / X exceeds 15, when the base film is peeled from the insulating resin layer after curing, the base film and the insulating resin layer cannot be peeled satisfactorily, and the base film is easily torn.

From the viewpoint of further suppressing the natural peeling of the base film from the insulating resin layer during curing and further suppressing the peeling failure of the base film when the base film is peeled from the insulating resin layer after curing, the above Y / X is preferably 0.7 or more, more preferably 1.0 or more, preferably 13 or less, and more preferably 11 or less.

From the viewpoint of further suppressing the natural peeling of the base film from the insulating resin layer during curing and further suppressing the peeling failure of the base film when the base film is peeled from the insulating resin layer after curing, the above X is It is preferably 0.3 or more, preferably 9 or less.

From the viewpoint of further suppressing the natural peeling of the base film from the insulating resin layer during curing and further suppressing the peeling failure of the base film when the base film is peeled from the insulating resin layer after curing, the above Y is It is preferably 0.5 or more, preferably 20 or less.

The peel strength (that is, X) of the base film with respect to the insulating resin layer is preferably 0.3 gf / cm or more, more preferably 0.5 gf / cm or more, preferably 9 gf / cm or less, more preferably 7 gf / cm. It is less than cm. When the peel strength is equal to or higher than the above lower limit, it is possible to suppress natural peeling of the base film from the insulating resin layer during transportation of the substrate, and also to insulate the base film even during laser irradiation for forming via holes. Natural peeling from the resin layer can be suppressed. When the peel strength is not more than the upper limit, the peel strength can be increased, and the roughness after the desmear treatment can be suppressed from being increased.

The peel strength of the base film with respect to the insulating resin layer can be measured using a tensile tester (“AG-5000B” manufactured by Shimadzu Corporation) under the condition of a crosshead speed of 5 mm / min.

The protruding distance (that is, Y) of the base film on one end side is preferably 0.5 mm or more, more preferably 1 mm or more, preferably 20 mm or less, and more preferably 15 mm or less. When the protruding distance of the base film on one end side is equal to or greater than the above lower limit, the base film can be satisfactorily peeled from the insulating resin layer after curing by using an automatic peeling device, and the laminated film can be satisfactorily peeled. It is possible to suppress cracks or cracks in the insulating resin layer when slitting one end or the other end of the laminated film during manufacturing. When the protruding distance of the base film on one end side is not more than the above upper limit, it is possible to suppress the natural peeling of the base film from the insulating resin layer during transportation of the laminated film, and also to suppress the manufacturing cost. be able to.

In the laminated film, it is preferable that the protective film is laminated on the surface of the insulating resin layer opposite to the base film side.

As a method of projecting the end face of the base film to the outside with respect to the end face of the insulating resin layer on one end side of the laminated films (0) and (1), the base film and the insulating resin layer There is a method of shifting the end face at the time of laminating with.

As a method of projecting the end face of the base film to the outside with respect to the end face of the insulating resin layer on both one end side of the laminated film (2) and the other end side opposite to the one end. Examples thereof include a method of shifting the end face when laminating the base film and the insulating resin layer. In the laminated film (2), the shifting distance of the end face is adjusted.

Examples of the method of aligning the end faces of the base material, the insulating resin layer, and the protective film on the other end side of the laminated film (1) opposite to the one end include the following methods. A method of aligning the end faces when laminating the base film and the insulating resin layer, and a laminate of the base film and the insulating resin layer, or the base film, the insulating resin layer, and the protective film. A method of slitting a laminate.

Examples of the method of making the protruding distance of the base film on the other end side of the laminated film (2A) smaller than the protruding distance of the base film on the one end side include the following methods. .. A method in which the protruding distance of the base film on the other end side is smaller than the protruding distance of the base film on the one end side when the base film and the insulating resin layer are laminated. A method of slitting a base film among a base film and an insulating resin layer. A method of slitting a base film and a protective film among a base film, an insulating resin layer and a protective film.

The method for producing a laminated film according to the present invention preferably has the following configuration (A) or (B). The manufacturing methods (A) and (B) are methods for manufacturing the laminated film (0). The manufacturing method (A) is a manufacturing method of the laminated film (1), and the manufacturing method (B) is a manufacturing method of the laminated film (2). The method for producing the laminated film (1) preferably includes the following configuration (A). The method for producing the laminated film (2) preferably includes the following configuration (B).

(A) In the method for producing the laminated film (1), an insulating resin layer is arranged on the surface of the base film so that the end face of the base film protrudes outward with respect to the end face on one end side of the insulating resin layer. The first step is provided. The method for producing the laminated film (1) preferably includes a second step of arranging the protective film on the surface of the insulating resin layer opposite to the base film side. In the method for producing the laminated film (1), on one end side of the laminated film corresponding to the one end of the insulating resin layer, the end face of the base film protrudes outward with respect to the end face of the insulating resin layer. To get. In the method for producing a laminated film (1), a laminated film (1) in which the end faces of the base film and the insulating resin layer are aligned on the other end side opposite to the one end of the laminated film is obtained.

(B) In the method for producing the laminated film (2), an insulating resin layer is arranged on the surface of the base film so that the end face of the base film protrudes outward with respect to the end face on one end side of the insulating resin layer. The first step is provided. In this first step, the end face of the base film is projected outward from both the end faces of one end side of the insulating resin layer and the other end side opposite to the one end on the surface of the base film. It is preferable to arrange an insulating resin layer in the air. The method for producing the laminated film (2) preferably includes a second step of arranging the protective film on the surface of the insulating resin layer opposite to the base film side. In the method for manufacturing the laminated film (2), the end face of the base film protrudes outward from the end face of the insulating resin layer on both one end side of the laminated film and the other end side opposite to the one end. Obtain the laminated film (2). In the method for producing the laminated film (2), the laminated film (2) is obtained in which the protruding distance of the base film on the other end side is smaller than the protruding distance of the base film on the one end side.

In the method (A) for producing a laminated film according to the present invention, after the second step, the base film, the insulating resin layer, and the protection are provided on the other end side of the insulating resin layer opposite to the one end. It is preferable to further include a third step of aligning the end faces with the film. In the method (A) for producing a laminated film according to the present invention, in the second step, the base film, the insulating resin layer, and the protective film are placed on the other end side of the insulating resin layer opposite to the one end. You may align the end faces with.

In the method (B) for producing a laminated film according to the present invention, after the second step, the base film on the other end side of the insulating resin layer protrudes from the other end side opposite to the one end side. It is preferable to further include a third step of making the distance to be smaller than the protruding distance of the base film on one end side.

From the viewpoint of further flattening the end face on the other end side of the laminated film (1), the protruding distance of the base film on the other end side of the laminated film (2) is set to the distance of the base film on the one end side. From the viewpoint of making the distance even smaller than the protruding distance, it is preferable to make the following slits. In the third step, it is preferable to slit the insulating resin layer. In the third step, it is preferable to slit the base film, the insulating resin layer, and the protective film.

In the laminated film of the present invention, an adherend such as a metal layer (for example, a laminated body of a substrate and a metal wiring) is generally laminated on the surface of the insulating resin layer. When the laminated film includes a protective film, the protective film is peeled off when the insulating resin layer is used in the laminated film. An adherend such as a metal layer (for example, a laminate of a substrate and a metal wiring) is generally laminated on the surface of the insulating resin layer after the protective film is peeled off.

Hereinafter, the present invention will be specifically described with reference to the drawings.

FIG. 1 is a cross-sectional view showing a laminated film according to the first embodiment of the present invention. FIG. 1 is a cross-sectional view showing the laminated film (1).

The laminated film 1 has one end 1a and the other end 1b opposite to the one end 1a. One end 1a and the other end 1b of the laminated film 1 are both end portions facing each other.

The laminated film 1 includes a base film 2 and an insulating resin layer 3. The insulating resin layer 3 is laminated on the first surface 2a of the base film 2.

The size of the base film 2 is larger than the size of the insulating resin layer 3 in the direction of connecting one end 1a and the other end 1b of the laminated film 1. The size of the insulating resin layer 3 is smaller than the size of the base film 2 in the direction connecting one end 1a and the other end 1b of the laminated film 1.

On one end 1a side of the laminated film 1, the end face of the base film 2 protrudes outward with respect to the end face of the insulating resin layer 3. At one end 1a of the laminated film 1, the end faces of the base film 2 and the insulating resin layer 3 are not aligned. On one end 1a side of the laminated film 1, there is a portion on the first surface 2a of the base film 2 where the insulating resin layer 3 is not laminated.

At one end 1a side of the laminated film 1, the protruding distance of the base film 2 is Y mm.

On the other end 1b side of the laminated film 1, the end faces of the base film 2 and the insulating resin layer 3 are aligned.

FIG. 2 is a cross-sectional view showing a laminated film according to a second embodiment of the present invention. FIG. 2 is a cross-sectional view showing the laminated film (2).

The laminated film 1A has one end 1Aa and the other end 1Ab opposite to one end 1Aa. One end 1Aa and the other end 1Ab of the laminated film 1A are both end portions facing each other.

The laminated film 1A includes a base film 2A and an insulating resin layer 3A. The insulating resin layer 3 is laminated on the first surface 2Aa of the base film 2A.

The size of the base film 2A is larger than the size of the insulating resin layer 3A in the direction of connecting one end 1Aa and the other end 1Ab of the laminated film 1A. The size of the insulating resin layer 3A is smaller than the size of the base film 2A in the direction connecting one end 1Aa and the other end 1Ab of the laminated film 1A.

At one end 1Aa side of the laminated film 1A, the end face of the base film 2A protrudes outward with respect to the end face of the insulating resin layer 3A. At one end 1Aa of the laminated film 1A, the end faces of the base film 2A and the insulating resin layer 3A are not aligned. On one end 1Aa side of the laminated film 1A, there is a portion where the insulating resin layer 3A is not laminated on the first surface 2Aa of the base film 2A.

On the other end 1Ab side of the laminated film 1A, the end face of the base film 2A protrudes outward with respect to the end face of the insulating resin layer 3A. At the other end 1Ab of the laminated film 1A, the end faces of the base film 2A and the insulating resin layer 3A are not aligned. On the other end 1Ab side of the laminated film 1A, there is a portion where the insulating resin layer 3A is not laminated on the first surface 2Aa of the base film 2A.

The protruding distance of the base film 2A on the other end 1Ab side of the laminated film 1A is smaller than the protruding distance of the base film 2A on the one end 1Aa side.

At one end 1Aa side of the laminated film 1A, the protruding distance of the base film 2A is Y mm.

The laminated film preferably has an MD (Machine Direction) direction and a TD (Transverse Direction) direction. The MD direction is the flow direction of the laminated film at the time of manufacturing the laminated film, for example, the length direction. The TD direction is a direction orthogonal to the flow direction of the laminated film at the time of manufacturing the laminated film and a direction orthogonal to the thickness direction of the laminated film. When the laminated film has an MD direction and a TD direction, the TD direction is the width direction. It is preferable that one end of the laminated film and the other end of the laminated film are both end portions facing each other in the width direction of the laminated film.

In the direction connecting the one end and the other end of the laminated film according to the present invention, the dimension of the base film is W ₁ mm, and the dimension of the insulating resin layer is W ₂ mm. In the laminated film according to the present invention, W ₁ is usually larger than _{W 2.} The laminated film according to the present invention usually satisfies _{W 1} > W _2.

W ₂ / W ₁ (ratio of the size of the insulating resin layer to the size of the base film) is preferably 0.9 or more, more preferably 0.92 or more, still more preferably 0.94 or more. , Especially preferably 0.96 or more. W ₂ / W ₁ (ratio of the size of the insulating resin layer to the size of the base film) is preferably 0.999 or less, more preferably 0.998 or less, still more preferably 0.997 or less. , Particularly preferably 0.996 or less. When W ₂ / W ₁ is equal to or higher than the above lower limit, the base film can be satisfactorily peeled from the insulating resin layer after curing by using an automatic peeling device, and one end of the laminated film or one end of the laminated film is produced during the production of the laminated film. It is possible to suppress cracks or cracks in the insulating resin layer when slitting the other end. When W ₂ / W ₁ is not more than the above upper limit, it is possible to suppress the natural peeling of the base film from the insulating resin layer during transportation of the laminated film, and the base film can be used efficiently. The cost can be suppressed.

Hereinafter, details of each layer constituting the laminated film according to the present invention will be described.

(Base film)
Examples of the base film include a metal foil, a polyester resin film such as a polyethylene terephthalate film and a polybutylene terephthalate film, an olefin resin film such as a polyethylene film and a polypropylene film, and a polyimide film. The surface of the base film may be mold-released, if necessary. The base film may be a metal foil or a resin film. The base film is preferably a resin film. When a metal foil is used as the base film, the metal foil is preferably a copper foil.

From the viewpoint of further suppressing peeling defects, the base film is preferably mold-released. From the viewpoint of further suppressing natural peeling due to the transfer of silicone, the mold release treatment is preferably a non-silicone transferable mold release treatment. The non-silicone transferable mold release treatment means a mold release treatment that does not contain silicone or a mold release treatment that is treated so that silicone does not migrate to the insulating resin layer side.

From the viewpoint of improving the operability of the laminated film and improving the laminateability of the insulating resin layer, the thickness of the base film is preferably 25 μm or more, more preferably 30 μm or more, preferably 75 μm or less, and more. It is preferably 50 μm or less. From the viewpoint of further suppressing natural peeling, the thickness of the base film is preferably 75 μm or less, more preferably 50 μm or less. From the viewpoint of further suppressing peeling defects, the thickness of the base film is preferably 25 μm or more.

The arithmetic mean roughness Ra of the surface of the base film on the insulating resin layer side is preferably 5 nm or more, more preferably 10 nm or more, preferably 400 nm or less, more preferably less than 400 nm, and further preferably 300 nm or less. When the arithmetic mean roughness is equal to or higher than the above lower limit and lower than the above upper limit, the natural peeling of the base film from the insulating resin layer during curing is further suppressed, and when the base film is peeled from the insulating resin layer after curing. In addition, poor peeling of the base film can be further suppressed.

The arithmetic mean roughness Ra is measured using a non-contact type surface roughness meter in VSI contact mode and with a 50x lens in a measurement range of 95.6 μm × 71.7 μm.

(Insulating resin layer)
The insulating resin layer is laminated on the surface of the base film. The insulating resin layer preferably contains an epoxy compound described later, an inorganic filler described later, and a curing agent described later.

[Epoxy compound]
The insulating resin layer preferably contains an epoxy compound. As the epoxy compound, a conventionally known epoxy compound can be used. The epoxy compound refers to an organic compound having at least one epoxy group. Only one type of the epoxy compound may be used, or two or more types may be used in combination.

Examples of the epoxy compound include bisphenol A type epoxy compound, bisphenol F type epoxy compound, bisphenol S type epoxy compound, phenol novolac type epoxy compound, biphenyl type epoxy compound, biphenyl novolac type epoxy compound, biphenol type epoxy compound, and naphthalene type epoxy compound. , Fluorene type epoxy compound, phenol aralkyl type epoxy compound, naphthol aralkyl type epoxy compound, dicyclopentadiene type epoxy compound, anthracene type epoxy compound, adamantan skeleton epoxy compound, tricyclodecane skeleton epoxy compound, naphthylene ether type Examples thereof include epoxy compounds and epoxy compounds having a triazine nucleus as a skeleton.

From the viewpoint of further increasing the adhesive strength between the cured product and the metal layer, the epoxy compound preferably has an aromatic skeleton, more preferably has a biphenyl skeleton, and further preferably is a biphenyl type epoxy compound. preferable.

From the viewpoint of further increasing the adhesive strength between the cured product and the metal layer, the content of the epoxy compound in 100% by weight of the insulating resin layer is preferably 10% by weight or more, more preferably 20% by weight or more. It is preferably 70% by weight or less, more preferably 65% by weight or less, still more preferably 60% by weight or less, and particularly preferably 55% by weight or less.

The molecular weight of the epoxy compound is more preferably 1000 or less. In this case, when the insulating resin layer is laminated on the base film, the inorganic filler can be uniformly present.

The molecular weight of the epoxy compound and the molecular weight of the curing agent described later mean the molecular weight that can be calculated from the structural formula when the epoxy compound or the curing agent is not a polymer and when the structural formula of the epoxy compound or the curing agent can be specified. To do. When the epoxy compound or the curing agent is a polymer, it means the weight average molecular weight.

[Inorganic filler]
The insulating resin layer preferably contains an inorganic filler. The use of an inorganic filler reduces dimensional changes due to heat of the cured product. Further, the surface roughness of the surface of the cured product is further reduced, and the adhesive strength between the cured product and the metal layer is increased.

In the conventional laminated film, if the insulating resin layer contains an inorganic filler, the base film may spontaneously peel off from the insulating resin layer during curing, and when the base film is further peeled from the insulating resin layer after curing, The base film and the insulating resin layer cannot be peeled off well, and the base film is easily torn. However, in the laminated film according to the present invention, even when the insulating resin layer contains an inorganic filler, the natural peeling of the base film from the insulating resin layer during curing is further suppressed, and the base film is made of an insulating resin after curing. When peeling from the layer, poor peeling of the base film can be further suppressed.

Examples of the inorganic filler include silica, talcite, clay, mica, hydrotalcite, alumina, magnesium oxide, aluminum hydroxide, aluminum nitride, and boron nitride.

The surface roughness of the surface of the cured product is reduced, the adhesive strength between the cured product and the metal layer is further increased, finer wiring is formed on the surface of the cured product, and the cured product has better insulation reliability. From the viewpoint of imparting, the inorganic filler is preferably silica or alumina, more preferably silica, and even more preferably fused silica. By using silica, the coefficient of thermal expansion of the cured product is further reduced, the surface roughness of the surface of the cured product is effectively reduced, and the adhesive strength between the cured product and the metal layer is effectively increased. The shape of silica is preferably spherical.

The inorganic filler is spherical silica from the viewpoint of advancing the curing of the resin regardless of the curing environment, effectively increasing the glass transition temperature of the cured product, and effectively reducing the coefficient of linear thermal expansion of the cured product. Is preferable.

The average particle size of the inorganic filler is preferably 10 nm or more, more preferably 50 nm or more, further preferably 100 nm or more, preferably 5 μm or less, more preferably 3 μm or less, still more preferably 1 μm or less, and particularly preferably 0.5 μm. It is as follows. When the average particle size of the inorganic filler is not less than the above lower limit and not more than the above upper limit, the adhesive strength between the cured product and the metal layer is further increased.

As the average particle size of the inorganic filler, a value of median diameter (d50) of 50% is adopted. The average particle size can be measured using a laser diffraction / scattering type particle size distribution measuring device. When the insulating resin layer contains two or more kinds of inorganic fillers, the average particle size of the inorganic fillers is measured for the entire inorganic filler contained in the insulating resin layer. The average particle size of the inorganic filler may be measured using the resin composition or the inorganic filler used to obtain the insulating resin layer.

The inorganic filler is preferably spherical, more preferably spherical silica. In this case, the surface roughness of the surface of the cured product is effectively reduced, and the adhesive strength between the cured product and the metal layer is effectively increased. When the inorganic filler is spherical, the aspect ratio of the inorganic filler is preferably 2 or less, more preferably 1.5 or less.

The inorganic filler is preferably surface-treated, more preferably a surface-treated product with a coupling agent, and even more preferably a surface-treated product with a silane coupling agent. As a result, the surface roughness of the surface of the roughened cured product is further reduced, the adhesive strength between the cured product and the metal layer is further increased, and finer wiring is formed on the surface of the cured product, and more. Even better inter-wiring insulation reliability and interlayer insulation reliability can be imparted to the cured product.

Examples of the coupling agent include a silane coupling agent, a titanium coupling agent, an aluminum coupling agent, and the like. Examples of the silane coupling agent include methacrylsilane, acrylicsilane, aminosilane, imidazolesilane, vinylsilane, and epoxysilane.

The content of the inorganic filler in 100% by weight of the insulating resin layer is preferably 30% by weight or more, more preferably 40% by weight or more, still more preferably 50% by weight or more, and particularly preferably 60% by weight or more. It is preferably 70% by weight or more. The content of the inorganic filler in 100% by weight of the insulating resin layer is preferably 90% by weight or less, more preferably 85% by weight or less, still more preferably 83% by weight or less, and particularly preferably 80% by weight or less. .. When the content of the inorganic filler is not less than the above lower limit and not more than the above upper limit, the surface roughness of the surface of the cured product is further reduced, the adhesive strength between the cured product and the metal layer is further increased, and the cured product is cured. Finer wiring is formed by the surface of the object. Further, the content of this inorganic filler makes it possible to reduce the coefficient of thermal expansion of the cured product and at the same time improve the smear removal property. When the content of the inorganic filler is at least the above lower limit, the dielectric loss tangent is effectively lowered. When the content of the inorganic filler is not more than the above upper limit, cracking of the insulating resin layer at the time of peeling of the protective film can be suppressed more effectively.

[Curing agent]
The insulating resin layer preferably contains a curing agent. The curing agent is not particularly limited. As the curing agent, a conventionally known curing agent can be used. Only one kind of the above-mentioned curing agent may be used, or two or more kinds may be used in combination.

Examples of the curing agent include cyanate compound (cyanate curing agent), phenol compound (phenol curing agent), amine compound (amine curing agent), thiol compound (thiol curing agent), imidazole compound, phosphine compound, acid anhydride, dicyandiamide, and the like. Examples thereof include a carbodiimide compound (carbodiimide curing agent), a maleimide compound (maleimide curing agent), and an active ester compound. The curing agent preferably has a functional group capable of reacting with the epoxy group of the epoxy compound.

From the viewpoint of further lowering the dielectric tangent, the curing agent preferably contains a cyanate compound, a phenol compound, a maleimide compound, an active ester compound, or a carbodiimide compound. From the viewpoint of further suppressing the natural peeling of the base film from the insulating resin layer during curing and further suppressing the peeling failure of the base film when the base film is peeled from the insulating resin layer after curing, the above-mentioned curing agent Preferably contains a phenol compound, a cyanate compound, a maleimide compound, or an active ester compound. The curing agent may contain a phenol compound, a cyanate compound, or an active ester compound.

The cyanate compound may be a cyanate ester compound (cyanate ester curing agent). Examples of the cyanate ester compound include a novolak type cyanate ester resin, a bisphenol type cyanate ester resin, and a prepolymer in which these are partially triquantized. Examples of the novolak type cyanate ester resin include phenol novolac type cyanate ester resin and alkylphenol type cyanate ester resin. Examples of the bisphenol type cyanate ester resin include bisphenol A type cyanate ester resin, bisphenol E type cyanate ester resin, and tetramethyl bisphenol F type cyanate ester resin.

Commercially available products of the above cyanate ester compounds include a phenol novolac type cyanate ester resin (“PT-30” and “PT-60” manufactured by Lonza Japan Co., Ltd.) and a prepolymer in which a bisphenol type cyanate ester resin is triquantized (Lonza Japan). Examples thereof include "BA-230S", "BA-3000S", "BTP-1000S" and "BTP-6020S") manufactured by the same company.

Examples of the phenol compound include novolak-type phenol, biphenol-type phenol, naphthalene-type phenol, dicyclopentadiene-type phenol, aralkyl-type phenol, and dicyclopentadiene-type phenol.

Commercially available products of the above phenol compounds include novolak-type phenol (“TD-2091” manufactured by DIC), biphenyl novolac-type phenol (“MEH-7851” manufactured by Meiwa Kasei Co., Ltd.), and aralkyl-type phenol compound (“MEH” manufactured by Meiwa Kasei Co., Ltd.). -7800 "), and phenols having an aminotriazine skeleton ("LA1356" and "LA3018-50P" manufactured by DIC) and the like can be mentioned.

The active ester compound is a compound containing at least one ester bond in the structure and having aromatic rings bonded to both sides of the ester bond. The active ester compound is obtained, for example, by a condensation reaction of a carboxylic acid compound or a thiocarboxylic acid compound with a hydroxy compound or a thiol compound. Examples of the active ester compound include a compound represented by the following formula (1).

In the above formula (1), X1 and X2 each represent a group containing an aromatic ring. Preferred examples of the group containing an aromatic ring include a benzene ring which may have a substituent and a naphthalene ring which may have a substituent. Examples of the substituent include a hydrocarbon group. The hydrocarbon group has preferably 12 or less carbon atoms, more preferably 6 or less carbon atoms, and even more preferably 4 or less carbon atoms.

The combination of X1 and X2 includes a combination of a benzene ring which may have a substituent and a benzene ring which may have a substituent, a benzene ring which may have a substituent, and a substitution. Examples thereof include a combination with a naphthalene ring which may have a group. Further, examples of the combination of X1 and X2 include a combination of a naphthalene ring which may have a substituent and a naphthalene ring which may have a substituent.

The active ester compound is not particularly limited. Examples of commercially available products of the active ester compound include "HPC-8000-65T", "EXB9416-70BK", "EXB8100-65T", and "EXB-8000L-65MT" manufactured by DIC Corporation.

The carbodiimide compound has a structural unit represented by the following formula (2). In the following formula (2), the right end and the left end are binding sites for other groups.

In the above formula (2), X is an alkylene group, a group in which a substituent is bonded to an alkylene group, a cycloalkylene group, a group in which a substituent is bonded to a cycloalkylene group, an arylene group, or a substituent bonded to an arylene group. It represents a group and p represents an integer of 1-5. When a plurality of X's exist, the plurality of X's may be the same or different.

In one preferred form, at least one X is an alkylene group, a group with a substituent attached to an alkylene group, a cycloalkylene group, or a group with a substituent attached to a cycloalkylene group.

Commercially available products of the above carbodiimide compounds include "carbodilite V-02B", "carbodilite V-03", "carbodilite V-04K", "carbodilite V-07", "carbodilite V-09" and "carbodilite" manufactured by Nisshinbo Chemical. Examples thereof include "10M-SP" and "carbodilite 10M-SP (revised)", and "Stavaxol P", "Stavaxol P400" and "Hikazil 510" manufactured by Rheinchemy.

As the maleimide compound, a conventionally known maleimide compound can be used. Only one type of the maleimide compound may be used, or two or more types may be used in combination.

The maleimide compound may be a bismaleimide compound.

Examples of the maleimide compound include N-phenylmaleimide and N-alkylbismaleimide.

The maleimide compound preferably has a skeleton derived from a diamine compound other than diamine diamine or a triamine compound other than trimer triamine.

The maleimide compound may or may not have an aromatic ring. The maleimide compound preferably has an aromatic ring.

In the maleimide compound, it is preferable that the nitrogen atom in the maleimide skeleton and the aromatic ring are bonded.

From the viewpoint of further enhancing the thermal dimensional stability of the cured product, the content of the maleimide compound is preferably 0.5% by weight or more, more preferably 0.5% by weight or more, based on 100% by weight of the components excluding the solvent in the insulating resin layer. It is 1% by weight or more, preferably 15% by weight or less, and more preferably 10% by weight or less.

The content of the maleimide compound in 100% by weight of the components excluding the inorganic filler and the solvent in the insulating resin layer is preferably 2.5% by weight or more, more preferably 5% by weight or more, still more preferably 7.5. By weight or more, preferably 50% by weight or less, more preferably 35% by weight or less. When the content of the maleimide compound is at least the above lower limit and at least the above upper limit, the thermal dimensional stability of the cured product can be further enhanced.

From the viewpoint of effectively exerting the effects of the present invention, the molecular weight of the maleimide compound is preferably 500 or more, more preferably 1000 or more, preferably less than 30,000, and more preferably less than 20,000.

The molecular weight of the maleimide compound means a molecular weight that can be calculated from the structural formula when the maleimide compound is not a polymer and when the structural formula of the maleimide compound can be specified. The molecular weight of the maleimide compound indicates the polystyrene-equivalent weight average molecular weight measured by gel permeation chromatography (GPC) when the maleimide compound is a polymer.

Examples of commercially available maleimide compounds include "BMI-4000" and "BMI-5100" manufactured by Daiwa Kasei Kogyo Co., Ltd., and Designer Molecules Inc. Examples include "BMI-3000" manufactured by the company.

The molecular weight of the curing agent is preferably 1000 or less. In this case, when the insulating resin layer is laminated on the base film, the inorganic filler can be uniformly present.

The total content of the epoxy compound and the curing agent in 100% by weight of the components excluding the inorganic filler in the insulating resin layer is preferably 75% by weight or more, more preferably 80% by weight or more, preferably 80% by weight or more. It is 99% by weight or less, more preferably 97% by weight or less. When the total content of the epoxy compound and the curing agent is not less than the above lower limit and not more than the above upper limit, a better cured product can be obtained and the melt viscosity can be adjusted, so that the inorganic filler is dispersed. The sex becomes good. Further, it is possible to prevent the insulating resin layer from getting wet and spreading in an unintended region during the curing process. Further, the dimensional change due to the heat of the cured product can be further suppressed. Further, when the total content of the epoxy compound and the curing agent is not more than the above lower limit, the melt viscosity does not become too low, and the insulating film tends to be excessively difficult to wet and spread in an unintended region during the curing process. is there. Further, when the total content of the epoxy compound and the curing agent is not more than the above upper limit, embedding in holes or irregularities of the circuit board becomes easy, and the inorganic filler tends to be less likely to exist unevenly. is there.

The content of the curing agent is preferably 30% by weight or more, more preferably 40% by weight or more, and preferably 70% by weight or less in 100% by weight of the components excluding the inorganic filler in the insulating resin layer. More preferably, it is 60% by weight or less. When the content of the curing agent is not less than the above lower limit and not more than the above upper limit, a better cured product can be obtained and the dielectric loss tangent is effectively lowered.

[Thermoplastic resin]
The insulating resin layer preferably contains a thermoplastic resin. Examples of the thermoplastic resin include polyimide resin, polyvinyl acetal resin, and phenoxy resin. Only one type of the above-mentioned thermoplastic resin may be used, or two or more types may be used in combination.

The thermoplastic resin is preferably a phenoxy resin from the viewpoint of effectively lowering the dielectric loss tangent and effectively improving the adhesion of the metal wiring regardless of the curing environment. By using the phenoxy resin, deterioration of embedding property in holes or irregularities of the circuit board of the insulating resin layer and non-uniformity of the inorganic filler can be suppressed. Further, by using the phenoxy resin, the melt viscosity can be adjusted, so that the dispersibility of the inorganic filler is improved, and the insulating resin layer is less likely to wet and spread in an unintended region during the curing process. The phenoxy resin is not particularly limited. As the phenoxy resin, a conventionally known phenoxy resin can be used. Only one type of the phenoxy resin may be used, or two or more types may be used in combination.

Examples of the phenoxy resin include phenoxy resins having skeletons such as bisphenol A type skeleton, bisphenol F type skeleton, bisphenol S type skeleton, biphenyl skeleton, novolak skeleton, naphthalene skeleton and imide skeleton.

Examples of commercially available phenoxy resins include "YP50", "YP55" and "YP70" manufactured by Nippon Steel & Sumitomo Metal Corporation, and "1256B40", "4250", "4256H40" and "4256H40" manufactured by Mitsubishi Chemical Corporation. 4275 ”,“ YX6954BH30 ”,“ YX8100BH30 ”and the like.

From the viewpoint of obtaining an insulating resin layer having more excellent storage stability, the weight average molecular weight of the thermoplastic resin is preferably 5000 or more, more preferably 10000 or more, preferably 100,000 or less, and more preferably 50,000 or less.

The weight average molecular weight of the thermoplastic resin indicates the polystyrene-equivalent weight average molecular weight measured by gel permeation chromatography (GPC).

The contents of the thermoplastic resin and the phenoxy resin are not particularly limited. The content of the thermoplastic resin (content of the phenoxy resin when the thermoplastic resin is a phenoxy resin) is preferably 1% by weight or more in 100% by weight of the components excluding the inorganic filler in the insulating resin layer. , More preferably 5% by weight or more, preferably 30% by weight or less, and more preferably 15% by weight or less. When the content of the thermoplastic resin is at least the above lower limit and at least the above upper limit, the embedding property of the insulating resin layer in the holes or irregularities of the circuit board is improved. When the content of the thermoplastic resin is at least the above lower limit, the formation of the insulating resin layer becomes easier, and a better insulating layer can be obtained. When the content of the thermoplastic resin is not more than the above upper limit, the coefficient of thermal expansion of the cured product becomes even lower. The surface roughness of the surface of the cured product is further reduced, and the adhesive strength between the cured product and the metal layer is further increased.

[Curing accelerator]
The insulating resin layer preferably contains a curing accelerator. By using the above-mentioned curing accelerator, the curing rate becomes even faster. By rapidly curing the insulating resin layer, the crosslinked structure in the cured product becomes uniform, the number of unreacted functional groups decreases, and as a result, the crosslinked density increases. The curing accelerator is not particularly limited, and conventionally known curing accelerators can be used. Only one kind of the above-mentioned curing accelerator may be used, or two or more kinds may be used in combination.

Examples of the curing accelerator include imidazole compounds, phosphorus compounds, amine compounds, organometallic compounds and the like.

Examples of the imidazole compound include 2-undecylimidazole, 2-heptadecylimidazole, 2-methylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-. 2-Methylimidazole, 1-benzyl-2-phenylimidazole, 1,2-dimethylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-cyanoethyl-2-un Decylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazolium trimerite, 1-cyanoethyl-2-phenylimidazolium trimerite, 2,4-diamino-6- [2' -Methylimidazolyl- (1')]-ethyl-s-triazine, 2,4-diamino-6- [2'-undecylimidazolyl- (1')]-ethyl-s-triazine, 2,4-diamino- 6- [2'-ethyl-4'-methylimidazolyl- (1')]-ethyl-s-triazine, 2,4-diamino-6- [2'-methylimidazolyl- (1')]-ethyl-s -Triazine isocyanuric acid adduct, 2-phenylimidazole isocyanuric acid adduct, 2-methylimidazole isocyanuric acid adduct, 2-phenyl-4,5-dihydroxymethylimidazole and 2-phenyl-4-methyl-5-dihydroxymethylimidazole And so on.

Examples of the phosphorus compound include triphenylphosphine and the like.

Examples of the amine compound include diethylamine, triethylamine, diethylenetetramine, triethylenetetramine, 4,4-dimethylaminopyridine and the like.

Examples of the organometallic compound include zinc naphthenate, cobalt naphthenate, tin octylate, cobalt octylate, bisacetylacetonate cobalt (II) and trisacetylacetonate cobalt (III).

The content of the curing accelerator is not particularly limited. The content of the curing accelerator is preferably 0.005% by weight or more, more preferably 0.01% by weight or more, and preferably 5% by weight or less in 100% by weight of the components excluding the inorganic filler in the insulating resin layer. , More preferably 3% by weight or less. When the content of the curing accelerator is at least the above lower limit and at least the above upper limit, the insulating resin layer is efficiently cured. If the content of the curing accelerator is in a more preferable range, the storage stability of the insulating resin layer becomes even higher, and a better cured product can be obtained.

[solvent]
The insulating resin layer does not contain or contains a solvent. Further, the solvent may be used to obtain a slurry containing the inorganic filler. Only one type of the solvent may be used, or two or more types may be used in combination.

Examples of the solvent include acetone, methanol, ethanol, butanol, 2-propanol, 2-methoxyethanol, 2-ethoxyethanol, 1-methoxy-2-propanol, 2-acetoxy-1-methoxypropane, toluene, xylene, methyl ethyl ketone, and the like. Examples thereof include N, N-dimethylformamide, methyl isobutyl ketone, N-methyl-pyrrolidone, n-hexane, cyclohexane, cyclohexanone and naphtha as a mixture.

Most of the solvent is preferably removed when the insulating resin layer is molded. Therefore, the boiling point of the solvent is preferably 200 ° C. or lower, more preferably 180 ° C. or lower. The content of the solvent in the insulating resin layer is not particularly limited. The content of the solvent can be appropriately changed to the extent that the layer shape of the insulating resin layer can be maintained.

[Other ingredients]
For the purpose of improving impact resistance, heat resistance, resin compatibility, workability, etc., the insulating resin layer is provided with a leveling agent, a flame retardant, a coupling agent, a coloring agent, an antioxidant, an ultraviolet deterioration inhibitor, etc. Other thermosetting resins and the like other than defoaming agents, thickeners, rock denaturing agents and epoxy compounds may be added.

Examples of the coupling agent include a silane coupling agent, a titanium coupling agent, an aluminum coupling agent, and the like. Examples of the silane coupling agent include vinylsilane, aminosilane, imidazolesilane, and epoxysilane.

Examples of the other thermosetting resin include polyphenylene ether resin, divinylbenzyl ether resin, polyarylate resin, diallylphthalate resin, polyimide resin, benzoxazine resin, benzoxazole resin, and acrylate resin.

Examples of the method for obtaining the insulating resin layer include the following methods. An extrusion molding method in which a material for forming an insulating resin layer is melt-kneaded using an extruder, extruded, and then molded into a film by a T-die, a circular die, or the like. A casting molding method in which a material for forming an insulating resin layer containing a solvent is cast and molded into a film. Other conventionally known film forming methods. Further, a material for forming an insulating resin layer can be laminated on a base film and heat-dried to obtain an insulating resin layer. An extrusion molding method or a casting molding method is preferable because it can be made thinner. The film includes a sheet.

A B-stage film is obtained by molding a material for forming an insulating resin layer into a film and heating and drying it at 50 ° C. to 150 ° C. for 1 minute to 10 minutes to the extent that curing by heat does not proceed too much. An insulating resin layer can be obtained.

The film-shaped insulating resin layer that can be obtained by the drying step as described above is referred to as a B stage film. The B stage film is in a semi-cured state. The semi-cured product is not completely cured and can be further cured.

The insulating resin layer is preferably a B stage film.

The minimum melt viscosity of the insulating resin layer (when the insulating resin layer is a B stage film, the B stage film) in the temperature range of 60 ° C. or higher and 180 ° C. or lower is preferably 5 mPa · s or more, preferably 10 mPa · s. That is all. When the minimum melt viscosity is at least the above lower limit, it is possible to prevent the resin from seeping into an unintended region during laminating and pressing, and effectively suppress peeling defects when the base film is peeled off after curing. Furthermore, natural peeling can be effectively suppressed. The upper limit of the minimum melt viscosity of the insulating resin layer (when the insulating resin layer is a B stage film, the B stage film) in the temperature range of 60 ° C. or higher and 180 ° C. or lower is not particularly limited. The minimum melt viscosity of the insulating resin layer (when the insulating resin layer is a B stage film, the B stage film) in a temperature range of 60 ° C. or higher and 180 ° C. or lower may be 200 mPa · s or less. It may be 150 mPa · s or less, 100 mPa · s or less, or 75 mPa · s or less.

The temperature at the time of the minimum melt viscosity is preferably 140 ° C. or lower, more preferably 130 ° C. or lower. When the temperature at the time of the minimum melt viscosity is not more than the above upper limit, the natural peeling due to the shrinkage of the base film can be effectively suppressed.

The minimum melt viscosity was determined by using a rheometer device (for example, "AR-2000" manufactured by TA Instruments) at a frequency of 6.28 rad / sec, a starting temperature of 60 ° C., a heating rate of 5 ° C./min, and strain 21. It is obtained by measuring the dynamic viscoelasticity under the condition of 8%.

From the viewpoint of further improving the laminateability of the insulating resin layer (when the insulating resin layer is a B stage film, the B stage film) and further suppressing the curing unevenness of the insulating resin layer, the thickness of the insulating resin layer is It is preferably 5 μm or more, more preferably 10 μm or more, preferably 200 μm or less, and more preferably 100 μm or less.

(Protective film)
In the laminated film, it is preferable that the protective film is laminated on the surface of the insulating resin layer opposite to the base film side.

Examples of the material of the protective film include polyolefins such as polypropylene and polyethylene, polyethylene terephthalate and the like. The material of the protective film is preferably polyolefin, more preferably polypropylene.

From the viewpoint of further improving the protective property of the insulating resin layer, the thickness of the protective film is preferably 5 μm or more, more preferably 10 μm or more, preferably 75 μm or less, and more preferably 60 μm or less.

(Other details of laminated film)
The laminated film according to the present invention is suitably used for forming an insulating layer in a multilayer printed wiring board. The insulating resin layer is suitably used for forming an insulating layer in a multilayer printed wiring board. An insulating layer can be formed by the insulating resin layer of the laminated film according to the present invention.

As an example of the multilayer printed wiring board, there is a multilayer printed wiring board including a circuit board, a plurality of insulating layers laminated on the circuit board, and a metal layer arranged between the plurality of insulating layers. At least one of the insulating layers is formed by the insulating resin layer. The insulating layer in contact with the circuit board may be formed by the insulating resin layer. The insulating layer arranged between the two insulating layers may be formed by the insulating resin layer. The insulating layer farthest from the circuit board may be formed by the insulating resin layer. Among the plurality of the insulating layers, the metal layer may be arranged on the outer surface of the insulating layer away from the circuit board.

(Manufacturing method of laminated structure)
In the method for producing a laminated structure according to the present invention, the above-mentioned laminated film is used, and the above-mentioned base film and the above-mentioned insulating resin layer are laminated on the opposite side of the above-mentioned insulating resin layer from the above-mentioned base film. It is provided with a laminating step of laminating the surface of the above on a member to be laminated having a metal layer on the surface. In the method for producing a laminated structure according to the present invention, a via hole is formed by irradiating the insulating resin layer with a laser from the base film side in a state where the base film and the insulating resin layer are laminated. It has a forming process.

Since the method for producing a laminated structure according to the present invention has the above configuration, it is possible to suppress natural peeling of the base film from the insulating resin layer in the curing step.

(Laminating process)
In the method for producing a laminated structure according to the present invention, the above-mentioned laminated film is used, and the above-mentioned base film and the above-mentioned insulating resin layer are laminated on the opposite side of the above-mentioned insulating resin layer from the above-mentioned base film. The surface of the above is laminated on a member to be laminated having a metal layer on the surface.

In the laminating step, when the laminated film includes the protective film, the protective film is peeled off, and the surface of the insulating resin layer exposed by the peeling is laminated on a member to be laminated having a metal layer on the surface.

The laminating step is preferably performed by laminating. The temperature at the time of laminating is preferably 80 ° C. or higher, preferably 120 ° C. or lower.

(Curing process)
The method for producing a laminated structure according to the present invention preferably includes a curing step for curing the insulating resin layer.

In the method for producing a laminated structure according to the present invention, it is preferable to cure the insulating resin layer. In the curing step, the insulating resin layer is cured to form a cured product. The curing of the insulating resin layer in the curing step may be pre-curing. The cured product also includes a pre-cured product that can be further cured. In the curing step, the insulating resin layer may be pre-cured to obtain a B stage film.

The curing step is preferably performed by heating. The heating temperature is preferably 130 ° C. or higher, preferably 200 ° C. or lower. The heating time is preferably 30 minutes or more, preferably 120 minutes or less.

In order to form fine irregularities on the surface of the cured product obtained by pre-curing the insulating resin layer, the cured product is preferably roughened. Prior to the roughening treatment, the cured product is preferably swelled. It is preferable that the cured product is swelled and further cured after the roughening treatment after the pre-curing and before the roughening treatment. However, the cured product does not necessarily have to be swelled.

As the method of the swelling treatment, for example, a method of treating the cured product with an aqueous solution of a compound containing ethylene glycol or the like as a main component or an organic solvent dispersion solution is used. The swelling liquid used for the swelling treatment generally contains an alkali as a pH adjuster or the like. The swelling liquid preferably contains sodium hydroxide. Specifically, for example, the swelling treatment is carried out by treating the cured product at a treatment temperature of 30 ° C. to 85 ° C. for 1 minute to 30 minutes using a 40 wt% ethylene glycol aqueous solution or the like. The temperature of the swelling treatment is preferably in the range of 50 ° C. to 85 ° C. If the temperature of the swelling treatment is too low, the swelling treatment takes a long time, and the adhesive strength between the cured product and the metal layer tends to be low.

For the roughening treatment, for example, a chemical oxidizing agent such as a manganese compound, a chromium compound or a persulfate compound is used. These chemical oxidizing agents are used as an aqueous solution or an organic solvent dispersion solution after water or an organic solvent is added. The roughening liquid used for the roughening treatment generally contains an alkali as a pH adjuster or the like. The roughening liquid preferably contains sodium hydroxide.

Examples of the manganese compound include potassium permanganate and sodium permanganate. Examples of the chromium compound include potassium dichromate and anhydrous potassium chromate. Examples of the persulfate compound include sodium persulfate, potassium persulfate, ammonium persulfate and the like.

The arithmetic mean roughness Ra of the surface of the cured product is preferably 5 nm or more, more preferably 10 nm or more, preferably 400 nm or less, more preferably less than 400 nm, still more preferably 300 nm or less, still more preferably less than 300 nm, in particular. It is preferably less than 200 nm, most preferably less than 150 nm. In this case, the adhesive strength between the cured product and the metal layer is increased, and the surface of the insulating layer forms finer wiring. Further, the conductor loss can be suppressed, and the signal loss can be suppressed low.

(Beer hall forming process)
In the method for producing a laminated structure according to the present invention, a via hole is formed by irradiating the insulating resin layer with a laser from the base film side in a state where the base film and the insulating resin layer are laminated.

Examples of the laser used in the via hole forming step include a CO ₂ laser and a UV laser.

From the viewpoint of using a general-purpose polyethylene terephthalate (PET) film as a base material, the laser is preferably a _{CO 2 laser.} On the other hand, when a UV laser is used as the laser, it is preferable to use a polyethylene naphthalate (PEN) film, a film containing an ultraviolet absorber, or the like.

The diameter of the via hole formed is not particularly limited, but is preferably 80 μm or less. The diameter of the via hole may be 10 μm or more, 30 μm or more, or 60 μm or more.

(Desmia process)
The method for producing a laminated structure according to the present invention preferably includes a step of removing smears inside the via hole by a desmear treatment (desmear step) after the via hole forming step. By providing the desmear step, smear, which is a resin residue derived from the resin component formed in the via hole forming step, can be effectively removed.

In the desmear step, for example, a chemical oxidizing agent such as a manganese compound, a chromium compound or a persulfate compound is used. These chemical oxidizing agents are used as an aqueous solution or an organic solvent dispersion solution after water or an organic solvent is added. The desmear treatment liquid used in the desmear process generally contains an alkali. The desmear treatment liquid preferably contains sodium hydroxide.

The desmear step may also serve as a roughening treatment step for roughening the surface of the insulating resin layer.

(Peeling process)
The method for producing a laminated structure according to the present invention preferably includes a step (peeling step) of peeling the base film from the insulating resin layer after the desmear step.

The peeling step is preferably performed using an automatic peeling device.

Since the method for producing a laminated structure according to the present invention has the above configuration, it is possible to suppress poor peeling of the base film in the peeling step.

(Other processes)
The method for producing a laminated structure according to the present invention includes a plating step of forming a metal layer by plating on the surface of an insulating resin layer exposed by peeling after the peeling step, and an insulating resin layer further after the plating step. It is preferable to include each step of the main curing step of curing.

Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples. The present invention is not limited to the following examples.

(Base film)
Base film A (polyethylene terephthalate (PET) film (Lintec Corporation "25X"), thickness 25 μm, width 550 mm, arithmetic mean roughness Ra 30 nm on the surface on the insulating resin layer side)
Base film B (polyethylene terephthalate (PET) film (Lintec Corporation "386501"), thickness 38 μm, width 550 mm, arithmetic mean roughness Ra 30 nm on the surface on the insulating resin layer side)
Base film C (polyethylene terephthalate (PET) film ("PLD386502" manufactured by Lintec Corporation), thickness 38 μm, width 550 mm, arithmetic mean roughness Ra7 nm of the surface on the insulating resin layer side)

The arithmetic mean roughness was measured using a non-contact type surface roughness meter (“WYKO NT3300” manufactured by Becoin Sturments) with a VSI contact mode and a 50x lens with a measurement range of 95.6 μm × 71.7 μm. The arithmetic average roughness was measured at 10 randomly selected measurement points and the average value of the measured values was adopted. ..

(Material for forming the insulating resin layer)
A material for forming the insulating resin layer was prepared as follows.

Material for forming the insulating resin layer A:
69.3 parts by weight of a cyclohexanone slurry (solid content 70% by weight) of vinylsilane-treated silica (“SOC2” manufactured by Admatex Co., Ltd.) was prepared. In this slurry, 5.6 parts by weight of a biphenyl type epoxy compound (“NC3000H” manufactured by Nippon Kayaku Co., Ltd.), 5.3 parts by weight of a bisphenol F type epoxy compound (“830S” manufactured by DIC Co., Ltd.), and a fluorene type epoxy compound ( "OGSOL PG-100" manufactured by Osaka Gas Chemical Co., Ltd.) 2.0 parts by weight was added. Using a stirrer, the mixture was stirred at 1200 rpm for 60 minutes, and it was confirmed that there were no undissolved substances. Then, 1.6 parts by weight of a phenol novolac curing agent (“H4” manufactured by Meiwa Kasei Co., Ltd.) and a toluene mixed solution (solid content 65% by weight) of an active ester curing agent (“HPC-8000-65T” manufactured by DIC Co., Ltd.) 13 A part by weight was added, and the mixture was stirred at 1200 rpm for 60 minutes, and it was confirmed that there were no undissolved substances. A mixed solution of methyl ethyl ketone and cyclohexanone (solid content: 30% by weight) of a bisphenol acetophenone skeleton phenoxy resin (“YX6954” manufactured by Mitsubishi Chemical Corporation) was prepared. 3.6 parts by weight of the mixed solution (solid content 30% by weight), 0.3 parts by weight of 2-ethyl-4-methylimidazole (“2E4MZ” manufactured by Shikoku Kasei Kogyo Co., Ltd.), and a leveling agent (Kusumoto Kasei Co., Ltd. LS-480 ") 0.1 part by weight was further added. The mixture was stirred at 1200 rpm for 30 minutes to obtain a material (varnish) for forming the insulating resin layer A.

Material for forming the insulating resin layer B:
Except for changing the active ester curing agent (“HPC-8000-65T” manufactured by DIC Corporation) to a phenol novolac curing agent (“MEH7851-H” manufactured by Meiwa Kasei Co., Ltd.), it is used as a material for forming the insulating resin layer A. In the same manner, a material (varnish) for forming the insulating resin layer B was obtained.

(Example 1)
Step of arranging the insulating resin layer on the surface of the base film:
Using a die coater, a material (varnish) for forming the obtained insulating resin layer A is applied onto the base film A with a width of 510 mm except for a range of 20 mm from both ends in the width direction of the base material. After the work, it was dried at an average temperature of 100 ° C. for 3 minutes to volatilize the solvent. In this way, an insulating resin layer A having a thickness of 40 μm and a width of 510 mm was formed on the base film A to obtain a laminate.

Step of aligning one end face in the width direction of the laminate:
A slitter at a position 30 mm inward from one end (the other end) in the width direction of the obtained laminate and a position 18 mm inward from the end (one end) opposite to the other end. Was slit at a speed of 10 m / min, and the end face of the base film on the other end side and the end face of the insulating resin layer were aligned with each other. In this way, a laminated film having a distance (Y) of 2 mm from the end face of the base film to the end face of the insulating resin layer on one end side was obtained.

(Examples 2 to 16 and Comparative Examples 1 to 5)
The type of the base film, the type of the insulating resin layer, and the distance (Y) at which the end face of the base film protrudes from the end face of the insulating resin layer on one end side of the laminated film are changed as shown in Tables 1 to 3. A laminated film was obtained in the same manner as in Example 1 except for the above.

(Evaluation)
(1) Peeling strength (X) of the base film with respect to the insulating resin layer
The obtained laminated film was measured using a tensile tester (“AG-5000B” manufactured by Shimadzu Corporation) under the condition of a crosshead speed of 5 mm / min, and the peel strength (X) of the base film with respect to the insulating resin layer was measured. Was measured.

(2) Y / X
On one end side of the obtained laminated film, the distance (Y) at which the end face of the base film protrudes from the end face of the insulating resin layer and the distance (Y) of the base film with respect to the insulating resin layer measured in (1) above. Y / X was calculated from the peel strength (X).

(3) Minimum melt viscosity and temperature at minimum melt viscosity The base film was peeled off from the obtained laminated film to obtain an insulating resin layer. With respect to the obtained insulating resin layer, a rheometer device (“AR-2000” manufactured by TA Instruments) was used to obtain a frequency of 6.28 rad / sec, a starting temperature of 60 ° C., a heating rate of 5 ° C./min, and strain 21. The dynamic viscoelasticity was measured under the condition of 8%, and the minimum melt viscosity and the temperature at the minimum melt viscosity were determined. The results are shown below.

Insulating resin layer A: Minimum melt viscosity 98 mPa · s, temperature at minimum melt viscosity 137 ° C
Insulating resin layer B: Minimum melt viscosity 50 mPa · s, temperature at minimum melt viscosity 128 ° C

(4) Natural peeling Laminating process:
A 340 mm × 510 mm CCL substrate (“E679FG” manufactured by Hitachi Kasei Kogyo Co., Ltd.) in which an inner layer circuit was formed by etching was prepared. Both sides of the CCL substrate were immersed in a copper surface roughening agent (“Mech Etch Bond CZ-8101” manufactured by MEC) to roughen the copper surface.

The obtained laminated film was cut into a size of 325 mm × 502 mm, set on both sides of the CCL substrate from the resin film side, and used with a diaphragm type vacuum laminator (“MVLP-500” manufactured by Meiki Co., Ltd.) to form the CCL substrate. The uncured laminated sample A was obtained by laminating on both sides of the above. Lamination was performed by reducing the pressure for 20 seconds, setting the atmospheric pressure to 13 hPa or less, pressing at 100 ° C. for 20 seconds, and further pressing at 100 ° C. and a pressure of 0.8 MPa for 40 seconds.

Curing process:
The insulating resin layer was heated at a heating temperature of 180 ° C. for 30 minutes to pre-cure the insulating resin layer.

In the above curing step, the presence or absence of natural peeling of the base film from the insulating resin layer was visually confirmed.

[Evaluation criteria for natural peeling]
◯: Spontaneous peeling does not occur Δ: Slight natural peeling occurs ×: Spontaneous peeling occurs

(5) Ripped base film (poor peeling)
After evaluating the above (4) natural peeling, the following steps were performed.

Beer hall forming process:
The base film and the insulating resin layer (B stage film) are laminated and pre-cured, and then the insulating resin layer _{is irradiated with a CO 2} laser (“LC-4KF212” manufactured by Hitachi Via Mechanics) from the base film side. A via hole was formed so as to penetrate the base film and the insulating resin layer so that the upper end diameter of the via hole was 60 μm. The irradiation conditions of the CO _{2 laser were as follows.}

[CO ₂ laser irradiation conditions]
Machining mode Burst
Period 0.100ms
Pulse width 0.018ms
Number of pulses 3 shots Aperture 3.5mm
2nd aperture 28mm
Power 3.3W

Peeling process:
The base film was peeled off from the insulating resin layer.

In the peeling step, the presence or absence of tearing of the base film was visually confirmed.

[Evaluation criteria for tearing of base film]
◯: The base film does not tear Δ: The base film tears slightly ×: The base film tears

The composition and results of the laminated film are shown in Tables 1 to 3 below.

1,1A ... Laminated film 1a, 1Aa ... One end 1b, 1Ab ... Other end 2,2A ... Base film 2a, 2Aa ... First surface 3,3A ... Insulating resin layer Y ... Base material on one end side of the laminated film The distance that the film sticks out

Claims (12)

A base film and an insulating resin layer laminated on the surface of the base film are provided.
On one end side of the laminated film, the end face of the base film protrudes most outward from the end face of the insulating resin layer.
When the peel strength of the base film with respect to the insulating resin layer is Xgf / cm and the protruding distance of the base film on one end side is Y mm, Y / X is 0.5 or more and 15 or less. Laminated film. The laminated film according to claim 1, wherein X is 0.3 or more and 9 or less. The laminated film according to claim 1 or 2, wherein Y is 0.5 or more and 20 or less. The laminated film according to any one of claims 1 to 3, wherein the base film has a thickness of 25 μm or more. The laminated film according to any one of claims 1 to 4, wherein the arithmetic average roughness Ra of the surface of the base film on the insulating resin layer side is 5 nm or more and less than 400 nm. The laminated film according to any one of claims 1 to 5, wherein the insulating resin layer contains an epoxy compound, an inorganic filler, and a curing agent. The laminated film according to claim 6, wherein the curing agent contains a phenol compound, a cyanate compound, a maleimide compound, or an active ester compound. On the other end side opposite to the one end of the laminated film, the end faces of the base film and the insulating resin layer are aligned, or the one end side of the laminated film and the other end side opposite to the one end. In both cases, the end face of the base film protrudes outward with respect to the end face of the insulating resin layer, and the distance of the base film protruding from the other end side is the base film on the one end side. The laminated film according to any one of claims 1 to 7, which is smaller than the protruding distance. The laminated film according to any one of claims 1 to 8, wherein the minimum melt viscosity of the insulating resin layer in a temperature range of 60 ° C. or higher and 180 ° C. or lower is 5 mPa · s or higher. The laminated film according to any one of claims 1 to 9, wherein the insulating resin layer is used for forming an insulating layer in a multilayer printed wiring board. The laminated film according to any one of claims 1 to 10 is used, and the base film and the insulating resin layer are laminated on the opposite side of the insulating resin layer from the base film. A laminating process of laminating the surface on a member to be laminated having a metal layer on the surface,
A method for producing a laminated structure, comprising a via hole forming step of irradiating the insulating resin layer with a laser from the base film side to form a via hole in a state where the base film and the insulating resin layer are laminated. .. The method for manufacturing a laminated structure according to claim 11, further comprising a curing step of curing the insulating resin layer between the laminating step and the via hole forming step.

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