Manufacturing method for resin-coated metal foil, manufacturing method for laminated board, manufacturing method for printed wiring board, and manufacturing method for semiconductor package

Abstract

To provide a manufacturing method of a metal foil with resin excellent in productivity and suppressed in warpage, as well as a manufacturing method of a laminate using the metal foil with resin manufactured by the manufacturing method, a manufacturing method of a printed wiring board and a manufacturing method of a semiconductor package.SOLUTION: A method for manufacturing a resin-coated metal foil having a metal foil 1 and a resin layer 2 formed on one side of the metal foil using a thermosetting resin composition, the method comprising: a warpage correction process for reducing warpage of the resin-coated metal foil, wherein the warpage correction process includes (A) a process of passing the resin-coated metal foil through a gap between a pair of opposing rolls 5 and pressing the metal foil, and (B) a process of installing two rolls separately, and while conveying the resin-coated metal foil with the resin layer surface of the resin-coated metal foil directed toward the two rolls, pressing a curl correction plate 6 between the two rolls and against a metal foil surface of the resin-coated metal foil to press the curl correction plate toward a resin layer side.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present embodiment relates to a method for manufacturing a resin-coated metal foil, a method for manufacturing a laminate, a method for manufacturing a printed wiring board, and a method for manufacturing a semiconductor package. [Background technology]

[0002] 2. Description of the Related Art With the recent trend toward smaller size and higher performance of electronic devices, printed wiring boards are being required to have higher wiring density and higher integration than ever before, as well as thinner substrates. To meet these requirements, resin-coated metal foils, which do not use a fiber substrate such as glass cloth but have a resin layer formed on a metal foil, are used in the manufacture of printed wiring boards. Resin-coated metal foils can be made thinner because they do not contain a fiber substrate such as glass cloth, and they are also suitable for increasing wiring density and high integration because they have excellent insulating layer smoothness and fine wiring properties. Furthermore, because resin-coated metal foils do not contain a fiber substrate such as glass cloth, they have excellent dielectric properties and are used in printed wiring boards that require high frequency compatibility.

[0003] Resin-coated metal foils are typically produced by applying a solvent-containing thermosetting resin composition to a metal foil and then heating and drying it. During this process, the volume of the thermosetting resin composition shrinks due to the evaporation of the solvent and the B-stage transformation of the thermosetting resin composition, which can cause the resin-coated metal foil to warp toward the resin layer. Since this warping reduces productivity when manufacturing printed wiring boards using resin-coated metal foils, it is desirable to suppress it.

[0004] Patent Document 1 discloses a method for producing resin-coated metal foil, as a method for suppressing warping of the ends of resin-coated metal foil, in which a thermosetting resin composition is applied to the surface of the metal foil and the foil is heated and dried by passing through a drying oven to bring it to a B-stage, characterized in that the heating temperature at a position 80% of the total length from the entrance to the exit of the drying oven is 100°C or more higher than the heating temperature near the entrance of the drying oven, and the heating temperature from this position to the exit is 30°C or more lower. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-025624 Summary of the Invention [Problem to be solved by the invention]

[0006] The technology of Patent Document 1 is said to be capable of producing a resin-coated metal foil with reduced edge warpage. However, the production method of Patent Document 1 is limited to using only materials that are compatible with the drying conditions, resulting in limited freedom in the selection of materials to be used. Therefore, there is a need for a production method of a resin-coated metal foil that is highly productive and reduces warpage.

[0007] In view of the current situation, the present embodiment aims to provide a method for manufacturing a resin-coated metal foil that is highly productive and suppresses warping, as well as a method for manufacturing a laminate using the resin-coated metal foil manufactured by the manufacturing method, a method for manufacturing a printed wiring board, and a method for manufacturing a semiconductor package. [Means for solving the problem]

[0008] The present inventors have conducted research to solve the above problems and have found that the present disclosure can solve the above problems. The present disclosure includes the following embodiments [1] to

[11] . [1] A method for producing a resin-coated metal foil having a metal foil and a resin layer formed on one side of the metal foil using a thermosetting resin composition, a warpage correction treatment for reducing warpage of the resin-coated metal foil, The warpage correction treatment includes the following treatment (A) and treatment (B): (A) Treatment: A treatment in which the resin-coated metal foil is pressed by passing it through a gap between a pair of opposing rolls. (B) Treatment: Two rolls are placed apart, and the resin-coated metal foil is transported with the resin layer side of the resin-coated metal foil facing the two rolls. A curl correcting plate is pressed between the two rolls and against the metal foil side of the resin-coated metal foil, and the curl correcting plate is pressed toward the resin layer side. [2] The method for producing a resin-coated metal foil according to the above [1], wherein in the treatment (A), of the pair of rolls, the roll that comes into contact with the metal foil is a resin roll, and the roll that comes into contact with the resin layer is a metal roll. [3] The method for producing a resin-coated metal foil according to the above [1] or [2], wherein in the treatment (B), the distance by which the curl correcting plate is pressed toward the resin layer is 1 to 25 mm. [4] The method for producing a resin-coated metal foil according to any one of the above [1] to [3], wherein in the treatment (B), the distance between the two rolls is 50 to 300 mm. [5] The method for producing a resin-coated metal foil according to any one of the above [1] to [4], wherein in the treatment (B), the cross-sectional shape of the tip of the curl correcting plate is convex or circular. [6] The method for producing a resin-coated metal foil according to any one of the above [1] to [5], wherein in the treatment (B), the conveying speed of the resin-coated metal foil is 1 to 15 m / min. [7] The method for producing a resin-coated metal foil according to any one of the above [1] to [6], wherein the thickness of the metal foil is 0.1 to 35 μm. [8] The method for producing a resin-coated metal foil according to any one of the above [1] to [7], wherein the resin layer has a thickness of 5 to 70 μm. [9] A method for producing a laminate, comprising forming an insulating layer using a resin-coated metal foil obtained by the method for producing a resin-coated metal foil according to any one of [1] to [8] above.

[10] A method for producing a printed wiring board, comprising forming a wiring pattern on a laminate obtained by the method for producing a laminate described in [9] above.

[11] A method for manufacturing a semiconductor package, comprising mounting a semiconductor element on a printed wiring board obtained by the method for manufacturing a printed wiring board according to

[10] above. [Effects of the Invention]

[0009] According to this embodiment, it is possible to provide a method for manufacturing a resin-coated metal foil that is highly productive and suppresses warping, as well as a method for manufacturing a laminate using the resin-coated metal foil manufactured by this manufacturing method, a method for manufacturing a printed wiring board, and a method for manufacturing a semiconductor package. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a schematic diagram showing one aspect of a resin-coated metal foil of the present embodiment. [Figure 2] FIG. 2 is a schematic diagram showing another aspect of the resin-coated metal foil of the present embodiment. [Figure 3] FIG. 2 is a schematic diagram showing one aspect of the (B) process of this embodiment. [Figure 4] FIG. 2 is a schematic diagram showing one aspect of the (B) process of this embodiment. [Figure 5] FIG. 2 is a cross-sectional view of one mode of a curl correcting plate used in the (B) process of the present embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] In this specification, a numerical range indicated using "to" indicates a numerical range that includes the numerical value before "to" as the minimum value and the numerical value after "to" as the maximum value. For example, the expression "X to Y" (X and Y are real numbers) means a range of values ​​that is equal to or greater than X and equal to or less than Y. In this specification, the expression "equal to or greater than X" means X and a value greater than X, and this also applies when the values ​​are different. In this specification, the expression "equal to or less than Y" means Y and a value less than Y. In the numerical ranges described in this specification, the upper or lower limit of the numerical range may be replaced with values ​​shown in the examples. Unless otherwise specified, each of the components and materials exemplified in this specification may be used alone or in combination of two or more. In this specification, the content of each component in a resin composition means the total amount of the multiple substances present in the resin composition, unless otherwise specified, when multiple substances corresponding to each component are present in the resin composition. In this specification, the term "resin composition" includes a mixture of the components described below and a product obtained by B-staging the mixture. Here, B-staging in this specification refers to bringing the mixture into a B-stage state as defined in JIS K6900 (1994), and is also called semi-curing. Any combination of the features described in this specification is also included in this embodiment. The mechanism of action described in this specification is speculation and does not limit the mechanism by which the resin composition according to this embodiment exhibits its effects.

[0012] [Method of manufacturing resin-coated metal foil] The method for producing a resin-coated metal foil of this embodiment includes: A method for producing a resin-coated metal foil having a metal foil and a resin layer formed on one surface of the metal foil using a thermosetting resin composition, comprising: a warping correction treatment for reducing warping of the resin-coated metal foil, In the method for producing a resin-coated metal foil, the warpage correction treatment includes the following treatment (A) and treatment (B): (A) Treatment: A treatment in which the resin-coated metal foil before the warp straightening treatment is pressed by passing it through a gap between a pair of opposing rolls. (B) Treatment: Two rolls are placed apart, and the resin-coated metal foil is transported with the resin layer side of the resin-coated metal foil facing the two rolls. A curl correcting plate is pressed between the two rolls and against the metal foil side of the resin-coated metal foil, and the curl correcting plate is pressed toward the resin layer side. The (A) process and the (B) process may be performed in any order. That is, the order may be (A) process first and (B) process, or (B) process first and (A) process. The (A) process and the (B) process may each be performed once, or may each be performed two or more times.

[0013] According to the method for producing a resin-coated metal foil of this embodiment, it is possible to produce a resin-coated metal foil with reduced warpage. Although the reason for this is not clear, it is thought that the warpage correction treatment included in the production method of this embodiment contributes to the reduction of warpage in the resin-coated metal foil. In order to correct the warpage of the resin-coated metal foil, it is necessary to apply a shear force to the resin layer near the contact interface with the metal foil, displacing the resin layer in the direction of elongation. In addition, it is necessary for the displacement of the resin layer to be relatively larger than the displacement of the metal foil. In the method for producing a resin-coated metal foil of this embodiment, the (A) treatment can increase the displacement of the resin layer, particularly near the interface with the metal foil, which makes the resin layer more susceptible to plastic deformation, thereby making it easier to reduce warpage. It is also presumed that the (B) treatment generates minute cracks that are not visible to the naked eye (although this point is unclear), which is why warpage can be effectively reduced even in a resin layer that is less susceptible to plastic deformation. Considering that a resin-coated metal foil having a resin layer that is resistant to plastic deformation may be used, it has been found that the (A) treatment alone does not necessarily result in sufficient reduction in warpage (see Comparative Example 2), and that the (B) treatment alone does not result in sufficient reduction in warpage (see Comparative Example 1). Furthermore, it has been found that performing the (B) treatment alone multiple times does not result in sufficient reduction in warpage (see Comparative Example 4), and that a synergistic effect in warpage reduction can be obtained by combining the (A) treatment and the (B) treatment.

[0014] Hereinafter, each member constituting the resin-coated metal foil produced by the production method of this embodiment will be described, and then the warpage correction treatment will be described in detail.

[0015] 1 is a schematic diagram of a resin-coated metal foil 10, which is one embodiment of the resin-coated metal foil obtained by the manufacturing method of this embodiment. The resin-coated metal foil 10 has a configuration in which a resin layer 2 is formed on one surface of a metal foil 1. 2 is a schematic diagram of a resin-coated metal foil 20, which is another embodiment of the resin-coated metal foil obtained by the manufacturing method of this embodiment. The resin-coated metal foil 20 has a configuration in which a resin layer 2 is formed on one surface of a metal foil 1. Furthermore, on the surface of the metal foil 1 opposite to the resin layer 2, a release layer 3 and a carrier foil 4 are laminated in this order. The resin-coated metal foil obtained by the manufacturing method of this embodiment may have the metal foil 1 and the resin layer 2 laminated directly together, or may have another layer between the metal foil 1 and the resin layer 2.

[0016] <Metal foil> Examples of metal foils include copper foil, tin foil, tin-lead alloy foil, and nickel foil. Among these, copper foil is preferred. The copper foil preferably has a copper content of 95% by mass or more. From the viewpoint of use in semiconductor packages, the metal foil preferably complies with JIS standards (electrolytic copper foil for printed wiring boards: JIS C6512, rolled copper foil for printed wiring boards: JIS C6513) or IPC standards (IPC 4562 Standard Grades 1, 2, 3).

[0017] The surface of the metal foil on which the resin layer is to be formed may be subjected to a roughening treatment from the viewpoint of adhesion. The roughening treatment can be carried out by forming roughening particles on the surface of the metal foil. The roughening particles are preferably, for example, electrodeposited particles made of a single element selected from copper, nickel, phosphorus, tungsten, arsenic, molybdenum, chromium, cobalt, and zinc, or electrodeposited particles made of an alloy containing one or more of these elements. The roughening particles may be used alone or in combination of two or more kinds.

[0018] In addition to the above-mentioned roughening treatment, the metal foil may have secondary particles, tertiary particles, an anti-corrosion layer, a heat-resistant layer, or the like formed thereon using, for example, a single element selected from nickel, cobalt, copper, and zinc, or an alloy containing one or more of these elements. In addition to the above layers, the surface may be subjected to a surface treatment such as chromate treatment or silane coupling treatment.

[0019] The thickness of the metal foil is not particularly limited and may be adjusted appropriately depending on the use of the resin-coated metal foil, but is preferably 0.1 to 35 μm, more preferably 0.3 to 15 μm, even more preferably 0.5 to 5 μm, and particularly preferably 1 to 2 μm. When the thickness of the metal foil is equal to or greater than the above-mentioned lower limit, the handleability of the resin-coated metal foil obtained by the manufacturing method of this embodiment tends to be further improved. On the other hand, when the thickness of the metal foil is equal to or greater than the above-mentioned lower limit, the resin-coated metal foil obtained by the manufacturing method of this embodiment tends to be more suitable for thinner substrates.

[0020] <Carrier foil> The carrier foil corresponds to a support provided as needed to improve handling when the metal foil is thin. Therefore, the carrier foil is removed during the manufacturing process of a printed wiring board, etc. In this embodiment, the carrier foil is not included in the metal foil constituting the resin-coated metal foil. Examples of the carrier foil include copper foil, aluminum foil, nickel foil, etc. Among these, copper foil is preferred.

[0021] The thickness of the carrier foil is preferably 5 to 50 μm, more preferably 10 to 35 μm, and even more preferably 10 to 25 μm, from the viewpoints of improving the handleability of the resin-coated metal foil and production costs. When the thickness of the carrier foil is equal to or greater than the above-mentioned lower limit, the handleability of the resin-coated metal foil obtained by the manufacturing method of this embodiment tends to be further improved. On the other hand, when the thickness of the carrier foil is equal to or less than the above-mentioned upper limit, the cost of the resin-coated metal foil obtained by the manufacturing method of this embodiment tends to be further reduced.

[0022] <Release layer> The release layer is a layer that is provided between the metal foil and the carrier layer as needed to facilitate peeling of the carrier foil from the metal foil. Note that in this embodiment, the release layer is not included in the metal foil that constitutes the resin-coated metal foil. The release layer may be, for example, a layer containing one or more metals selected from chromium, nickel, cobalt, iron, molybdenum, titanium, tungsten, phosphorus, copper, and aluminum. These metals may be alloys, hydrates, oxides, etc. The release layer may be a single layer or multiple layers. The release layer can be formed by, for example, wet plating such as electroplating, electroless plating, and immersion plating; or dry plating such as sputtering, chemical vapor deposition (CVD), and physical vapor deposition (PDV).

[0023] <Resin layer> The resin layer is a layer formed on one side of the metal foil using a thermosetting resin composition, and is typically used as an insulating layer in applications such as printed wiring boards. The thickness of the resin layer is not particularly limited and may be adjusted appropriately depending on the use of the resin-coated metal foil, but is preferably 5 to 70 μm, more preferably 10 to 50 μm, and even more preferably 15 to 30 μm. When the thickness of the resin layer is equal to or greater than the above-mentioned lower limit, the insulating properties of the insulating layer formed from the resin-coated metal foil obtained by the manufacturing method of this embodiment tend to be further improved. On the other hand, when the thickness of the resin layer is equal to or less than the above-mentioned upper limit, the resin-coated metal foil obtained by the manufacturing method of this embodiment tends to be further suited to thinner substrates.

[0024] The composition of the thermosetting resin composition used to form the resin layer may be appropriately determined depending on the intended use of the resin-coated metal foil, etc. Examples of the thermosetting resin contained in the thermosetting resin composition include epoxy resins, phenolic resins, unsaturated imide resins, cyanate resins, isocyanate resins, benzoxazine resins, oxetane resins, amino resins, unsaturated polyester resins, allyl resins, dicyclopentadiene resins, silicone resins, triazine resins, and melamine resins. Among these, epoxy resins and unsaturated imide resins are preferred, unsaturated imide resins are more preferred, and maleimide resins are even more preferred. The maleimide resin may be a prepolymer obtained by Michael addition of a maleimide compound and a diamine compound. The thermosetting resin may be used alone or in combination of two or more kinds.

[0025] In addition to the thermosetting resin, the thermosetting resin composition may contain, for example, an inorganic filler, a curing agent, a curing accelerator, a thermoplastic resin, an elastomer, an organic filler, a flame retardant, other additives, etc. These may be used alone or in combination of two or more. Examples of inorganic fillers include silica, alumina, talc, mica, aluminum hydroxide, magnesium hydroxide, calcium carbonate, aluminum borate, and borosilicate glass. Examples of the curing agent include phenol compounds, amine compounds, acid anhydrides, etc. The curing agent is preferably selected appropriately depending on the type of thermosetting resin. Examples of the curing accelerator include imidazoles and derivatives thereof; organic phosphorus compounds; secondary amines, tertiary amines, and quaternary ammonium salts. Examples of thermoplastic resins and elastomers include polyphenylene ether and its derivatives, polybutadiene and its derivatives, and styrene-based thermoplastic elastomers. Examples of organic fillers include polytetrafluoroethylene (PTFE) particles; acrylonitrile butadiene copolymers such as crosslinked NBR particles obtained by copolymerizing acrylonitrile and butadiene, and copolymers of acrylonitrile, butadiene, and a carboxylic acid such as acrylic acid; and so-called core-shell rubber particles having a core of polybutadiene, NBR, silicone rubber, or the like and a shell of an acrylic acid derivative. Examples of the flame retardant include phosphorus-based flame retardants, metal hydrates, and halogen-based flame retardants. Other additives include ultraviolet absorbers such as benzotriazoles; antioxidants such as hindered phenol antioxidants and styrenated phenol antioxidants; photopolymerization initiators such as benzophenones, benzil ketals and thioxanthone; fluorescent brightening agents such as stilbene derivatives, urea compounds, and adhesion improvers such as silane coupling agents.

[0026] The content of the thermosetting resin in the thermosetting resin composition is preferably 30 to 95 parts by mass, more preferably 40 to 90 parts by mass, and even more preferably 50 to 80 parts by mass, per 100 parts by mass of the total resin components in the thermosetting resin composition. The content of the thermoplastic resin in the thermosetting resin composition is preferably 1 to 40 parts by mass, more preferably 5 to 35 parts by mass, even more preferably 15 to 35 parts by mass, and particularly preferably 20 to 35 parts by mass, relative to 100 parts by mass of the total resin components in the thermosetting resin composition. The content of the elastomer in the thermosetting resin composition is preferably 1 to 30 parts by mass, more preferably 5 to 25 parts by mass, even more preferably 5 to 20 parts by mass, and particularly preferably 5 to 15 parts by mass, relative to 100 parts by mass of the total resin components in the thermosetting resin composition. The content of the curing accelerator in the thermosetting resin composition is preferably 0.01 to 5 parts by mass, more preferably 0.1 to 5 parts by mass, and even more preferably 0.5 to 3 parts by mass, relative to 100 parts by mass of the total resin components in the thermosetting resin composition. The content of the inorganic filler in the thermosetting resin composition is preferably 20 to 300 parts by mass, more preferably 30 to 150 parts by mass, even more preferably 40 to 100 parts by mass, and particularly preferably 40 to 70 parts by mass, relative to 100 parts by mass of the total resin components in the thermosetting resin composition. The content of the organic filler in the thermosetting resin composition is preferably 20 to 300 parts by mass, more preferably 40 to 150 parts by mass, even more preferably 40 to 100 parts by mass, and particularly preferably 45 to 75 parts by mass, relative to 100 parts by mass of the total resin components in the thermosetting resin composition. Here, in this specification, the term "resin component" refers to a resin or a compound that forms a resin through a curing reaction, and examples of resin components include thermosetting resins, thermoplastic resins, and elastomers. Furthermore, when a thermosetting resin composition contains, as optional components, resins or compounds that form a resin through a curing reaction in addition to the above components, these optional components are also included in the resin component. On the other hand, curing accelerators, inorganic fillers, and organic fillers are not included in the resin component.

[0027] The thermosetting resin composition may contain an organic solvent to facilitate layer formation. A thermosetting resin composition containing an organic solvent may be referred to as a "resin varnish." Examples of organic solvents include ketone-based solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; acetate-based solvents such as ethyl acetate, butyl acetate, cellosolve acetate, propylene glycol monomethyl ether acetate, and carbitol acetate; carbitol-based solvents such as cellosolve and butyl carbitol; aromatic hydrocarbon-based solvents such as toluene and xylene; and amide-based solvents such as dimethylformamide, dimethylacetamide, and N-methylpyrrolidone. One organic solvent may be used alone, or two or more organic solvents may be used in combination. Among these, toluene and methyl isobutyl ketone are preferred from the viewpoint of solubility.

[0028] When the thermosetting resin composition contains an organic solvent, the solid content thereof is not particularly limited, but from the viewpoint of facilitating coating properties and controlling the thickness of the resin layer, it is preferably 25 to 80 mass %, more preferably 30 to 65 mass %, and even more preferably 35 to 50 mass %. In this embodiment, the solid content refers to a non-volatile resin component, and includes those that are liquid, syrup-like, or waxy at room temperature around 25°C, and does not necessarily mean that they are solid.

[0029] The thermosetting resin composition can be produced by blending the above components with an organic solvent, if necessary, and mixing them using a known stirrer or the like. When mixing, the components may be dissolved or dispersed while being stirred. The mixing order of the raw materials, the mixing temperature, the mixing time, and other conditions are not particularly limited and may be set arbitrarily depending on the types of raw materials, etc. Next, the manufacturing method of this embodiment will be described.

[0030] <Preparation of resin-coated metal foil before warping treatment> As described above, the warpage correction treatment in the manufacturing method of this embodiment includes the following treatment (A) and treatment (B). (A) Treatment: A treatment in which the resin-coated metal foil is pressed by passing it through a gap between a pair of opposing rolls. (B) Treatment: Two rolls are placed apart, and the resin-coated metal foil is transported with the resin layer side of the resin-coated metal foil facing the two rolls. A curl correcting plate is pressed between the two rolls and against the metal foil side of the resin-coated metal foil, and the curl correcting plate is pressed toward the resin layer side.

[0031] The resin-coated metal foil before the warp straightening treatment can be obtained, for example, by applying a resin varnish to the metal foil and then heating and drying it. Preferably, the heating and drying removes the organic solvent contained in the resin varnish and also converts the thermosetting resin into a B-stage. The heating temperature in the heat drying is preferably 80 to 200°C, more preferably 90 to 170°C, and even more preferably 100 to 150°C, from the viewpoints of productivity and appropriately bringing the thermosetting resin into the B-stage. The heating time in the heat drying is preferably 0.5 to 30 minutes, more preferably 1 to 10 minutes, and even more preferably 2 to 5 minutes, from the viewpoints of productivity and appropriately bringing the thermosetting resin into the B-stage. However, the heating temperature and heating time in the heat drying are conditions that are adjusted depending on the type of material used in the resin layer, the content of the organic solvent, the use of the resulting resin-coated metal foil, etc., and are not limited to the above ranges. The preferred embodiments of the metal foil, the thermosetting resin composition, and the resin layer are as described above.

[0032] <(A) Processing> In the (A) treatment, a warpage correction treatment is carried out in which the resin-coated metal foil prepared above before the warpage correction treatment or the resin-coated metal foil obtained by carrying out the (B) treatment is pressed by passing it through the gap between a pair of opposing rolls. From the viewpoint of reducing warpage, it is preferred that the roll in contact with the metal foil of the pair of rolls is a resin roll, and the roll in contact with the resin layer is a metal roll.

[0033] The shape of the resin roll and the metal roll is not particularly limited as long as they are rotatable, and examples thereof include a cylindrical body, a columnar body, etc. Among these, a cylindrical body having a perfectly circular cross section is preferred from the viewpoint of the homogeneity of the obtained resin-coated metal foil. Examples of the resin roll include a fluororesin roll, a polyimide resin roll, a polyurethane resin roll, a polyolefin resin roll, etc. Among these, a polyurethane resin roll is preferred. Examples of metal rolls include stainless steel rolls, chrome molybdenum steel rolls, etc. Among these, stainless steel rolls are preferred from the viewpoints of mechanical strength, abrasion resistance, ease of handling, etc. The metal roll may be surface-treated to prevent scratches and wear on the surface. Examples of surface treatment methods for metal rolls include nickel plating, electroless nickel plating, nickel-boron plating, hard chrome plating, and Parker plating. Among these, hard chrome plating is preferred. It is preferable that both the resin roll and the metal roll have a smooth surface from the viewpoint of the homogeneity of the resin-coated metal foil to be obtained.

[0034] The diameters of the resin roll and the metal roll are not particularly limited, but from the viewpoint of preventing cracks and reducing warpage, each is preferably 100 to 500 mm, more preferably 200 to 400 mm, and even more preferably 250 to 300 mm.

[0035] The feeding speed of the resin-coated metal foil by the resin roll and metal roll is not particularly limited, but from the viewpoint of productivity and warp correction effect, it is preferably 1 to 15 m / min, more preferably 1 to 10 m / min, and even more preferably 1 to 5 m / min.

[0036] The roll load in the (A) treatment is not particularly limited, but is preferably 0.3 to 12 tons, more preferably 1 to 12 tons, and even more preferably 3 to 12 tons, and may be 1 to 8 tons, 2 to 5 tons, 5 to 12 tons, or 8 to 12 tons. The upper limit of the roll load may be 11 tons or less, or 10 tons or less, depending on the design of the equipment. When the roll load in the (A) treatment is equal to or greater than the above lower limit, a more excellent warpage correction effect tends to be obtained. On the other hand, when the roll load in the (A) treatment is equal to or less than the above upper limit, unintended deformation of the resin-coated metal foil due to the load tends to be suppressed.

[0037] The resin roll and the metal roll may have a heat source inside the roll and a mechanism for heating the roll surface. In this case, the resin roll and the metal roll may be heated, but from the viewpoint of suppressing deterioration of the resin-coated metal foil, it is preferable not to heat them. The roll surface temperatures of the resin roll and the metal roll are not particularly limited, but from the viewpoints of productivity and warp correction effect, and of suppressing deterioration of the resin-coated metal foil, each is preferably 10 to 40°C, more preferably 15 to 35°C, and even more preferably 20 to 30°C.

[0038] The treatment (A) may be a treatment in which the resin-coated metal foil is passed through the gap between the pair of opposing rolls only once, or may be a treatment in which the resin-coated metal foil is passed through the gap between the pair of opposing rolls two or more times. When the resin-coated metal foil is passed through the gap between the pair of opposing rolls two or more times, the combination of rolls used in the first pass and the combination of rolls used in the second pass may be the same or different.

[0039] <(B) Processing> In the treatment (B), the resin-coated metal foil prepared as above before the warp straightening treatment or the resin-coated metal foil obtained by carrying out the treatment (A) is used. The process (B) will be explained in detail with reference to Figures 3 and 4. Two rolls 5, 5 are placed apart, and the resin-coated metal foil 10 is transported with the surface of the resin layer 2 of the resin-coated metal foil 10 facing the two rolls 5, 5. A curl corrector 6 is pressed between the two rolls 5, 5 against the surface of the metal foil 1 of the resin-coated metal foil 10, and the curl corrector 6 is pressed toward the resin layer 2. The material of the curl correcting plate 6 is not particularly limited as long as it has high hardness, and examples thereof include metal, resin, wood, etc. Among these, from the viewpoint of durability, metal and resin are preferred as the material of the curl correcting plate 6, and metal is more preferred. The cross-sectional shape of the tip of the curl correcting plate 6 (the portion in contact with the metal foil 1) is not particularly limited, but is preferably convex or circular. Here, as for the convex shape, from the viewpoint of reducing warpage, as in the cross-sectional view of the curl correcting plate 6 shown in Fig. 3, a mode in which the tip angle 7 is an acute angle is preferred, the tip angle 7 is more preferably 30 to 80°, and the tip angle 7 is even more preferably 40 to 75°. Furthermore, as for the circular shape, from the viewpoint of reducing warpage, as in the cross-sectional view of the curl correcting plate 6 shown in Fig. 5, a state in which the diameter of the circle 9 in the cross section of the tip of the curl correcting plate 6 is 1 to 7 mm, a state in which the diameter of the circle 9 is more preferably 1 to 6 mm, and a state in which the diameter of the circle 9 is even more preferably 2 to 5 mm.

[0040] From the viewpoint of reducing warpage, the distance 8 by which the curl correcting plate 6 is pressed toward the resin layer 2 is preferably 1 to 25 mm, more preferably 2 to 20 mm, and even more preferably 2 to 18 mm. The distance 8 by which the curl correcting plate 6 is pressed toward the resin layer 2 may be 2 to 15 mm, 5 to 15 mm, 8 to 23 mm, 12 to 23 mm, 15 to 23 mm, or 15 to 18 mm.

[0041] The distance 5' between the two rolls 5, 5 is the distance from the center of a roll 5 to the center of the other roll 5, and from the viewpoint of reducing warping, is preferably 50 to 300 mm, more preferably 50 to 200 mm, even more preferably 70 to 200 mm, particularly preferably 70 to 150 mm, and most preferably 80 to 120 mm. The curl corrector plate 6 is positioned between the two rolls 5, 5. This allows the resin-coated metal foil 10 to be pressed down by the two rolls 5, 5 when the metal foil 1 is pressed toward the resin layer 2, effectively reducing warpage of the resin-coated metal foil 10. The curl corrector plate 6 is preferably positioned within a range of ±5 mm from the midpoint between the two rolls 5, 5, and more preferably positioned at the midpoint between the two rolls 5, 5.

[0042] From the viewpoint of preventing the surface of the metal foil 1 from being scratched, it is preferable to place a protective film such as a Teflon (registered trademark) sheet between the metal foil 1 of the resin-coated metal foil 10 and the curl correcting plate 6. From the viewpoint of not impeding the warp reduction effect, the thickness of the protective film is preferably 0.3 to 3 mm, more preferably 0.5 to 2 mm, and even more preferably 0.5 to 1.5 mm.

[0043] In the treatment (B), the conveying speed of the resin-coated metal foil is preferably 1 to 15 m / min, more preferably 1 to 10 m / min, and even more preferably 1 to 5 m / min. By setting the conveying speed to the same speed as the feeding speed of the resin-coated metal foil by the resin roll and metal roll described in the treatment (A), it is possible to perform the treatment (A) and the treatment (B) by connecting them. (B) The treatment may be carried out once or twice or more.

[0044] [Laminate manufacturing method] The method for producing a laminated board of this embodiment includes forming an insulating layer using a resin-coated metal foil obtained by the method for producing a resin-coated metal foil of this embodiment. The method for manufacturing the laminate of this embodiment is, for example, to laminate the resin-coated metal foil of this embodiment on a core material such as a prepreg with the resin layer facing the core material, and then heat-pressure mold the laminate, thereby curing the resin layer and forming an insulating layer. The heating temperature during hot-press molding is preferably 150 to 250°C, more preferably 160 to 220°C, and even more preferably 160 to 200°C. The pressure during hot and pressure molding is preferably 2 to 5 MPa, more preferably 3 to 5 MPa, and even more preferably 3 to 4 MPa. There are no particular restrictions on the pressurizing method, and a multi-stage pressurizing method may be used. After the hot and pressure molding is completed, the material may be depressurized and cooled.

[0045] [Printed wiring board manufacturing method] The method for manufacturing a printed wiring board of this embodiment is a method for manufacturing a printed wiring board that includes a step of forming a wiring pattern on the laminate obtained by the method for manufacturing a laminate of this embodiment. Examples of methods for forming a wiring pattern include known methods such as a subtractive method, a full-additive method, a semi-additive method (SAP: Semi-Additive Process), and a modified semi-additive method (m-SAP: modified Semi-Additive Process). Thereafter, if necessary, the resin-coated metal foil of this embodiment or another resin-coated metal foil may be further laminated, and the laminate may be repeatedly heated and pressurized to form a multilayer structure, thereby producing a multilayer printed wiring board.

[0046] [Semiconductor package manufacturing method] The method for manufacturing a semiconductor package of this embodiment is a method for manufacturing a semiconductor package in which a semiconductor element is mounted on a printed wiring board obtained by the manufacturing method of this embodiment. Specifically, for example, a method can be mentioned in which a semiconductor element such as a semiconductor chip or memory is mounted by a known method at a predetermined position on a printed wiring board obtained by the manufacturing method of this embodiment, and the semiconductor element is sealed with a sealing resin or the like. [Example]

[0047] The present embodiment will be specifically described below with reference to examples, although the present embodiment is not limited to the following examples.

[0048] [Measurement of warpage] The resin-coated metal foil prepared in each example after warpage correction treatment was cut into a size of 515 mm x 415 mm, placed on a flat table, and the height of the warpage at the four corners was measured with a ruler, and the maximum value among these was evaluated as the amount of warpage (mm). The target value for the amount of warpage is 15 mm or less, and 10 mm or less is more preferable.

[0049] [Production of Thermosetting Resin Composition] Manufacturing Example 1 The components were mixed in the proportions shown in Table 1, and a thermosetting resin composition (resin varnish) with a solid content of 40 mass % was prepared using toluene, methyl isobutyl ketone, and propylene glycol monomethyl ether as organic solvents. The numerical values ​​of the blending compositions shown in Table 1 are parts by mass of solid content, and in the case of a solution or dispersion, are amounts converted to solid content.

[0050] [Table 1]

[0051] [Manufacturing resin-coated metal foil] Examples 1 to 3, Comparative Examples 1 to 4 The thermosetting resin composition obtained in Production Example 1 was applied to a roll of copper foil with a carrier foil (manufactured by Mitsui Mining & Smelting Co., Ltd., product name "MT18FL-1.5", width: 540 mm, copper foil thickness: 1.5 μm, carrier foil thickness: 18 μm) and dried by heating at 130°C for 3 minutes to form a resin layer with a thickness of 20 μm on one side of the copper foil. This copper foil with the resin layer provided thereon corresponds to the resin-coated metal foil before the warp straightening treatment, and was in a state where it was warped toward the resin layer side. In each example, the resin-coated metal foil obtained above before the warp straightening treatment was pressed through the gap between a pair of rolls shown in Table 2 (treatment (A)), and then the resin-coated metal foil was pushed up from the metal foil side to the resin layer side using a curl straightening plate under the conditions shown in Table 2 (treatment (B)), thereby obtaining resin-coated metal foils A to C after the warp straightening treatment. On the other hand, in Comparative Examples 1 and 2, the method of not performing the (A) treatment and the method of not performing the (B) treatment in the above Examples were employed, respectively, to obtain resin-coated metal foils D to E after warpage straightening. In Comparative Example 3, no warpage straightening treatment was performed, and the resin-coated metal foil before warpage straightening was designated as resin-coated metal foil F. In Comparative Example 4, the (A) treatment was not performed, and only the (B) treatment was repeated three times to obtain resin-coated metal foil G after warpage straightening. In the process (A), the details of the rolls listed in Table 2 are as follows. Resin roll: Polyurethane resin roll with a roll diameter of 300 mm Metal roll: 300mm diameter stainless steel roll (hard chrome plated) In the (B) treatment, the details of the curl correction plate and other conditions shown in Table 2 are as follows. Curl correction plate: Made of SUS, the cross section of the tip is convex, the tip angle is 50° Roll diameter of Roll 5,5: 20 mm Distance between rolls 5,5: 100mm Position of curl correction plate: Center point between rolls 5 and 5 Between the curl correction plate and the resin-coated metal foil: a Teflon (registered trademark) sheet (thickness 1 mm) was sandwiched.

[0052] The amount of warping of each of the resin-coated metal foils obtained above was evaluated by the above-mentioned method, and the results are shown in Table 2.

[0053] [Table 2]

[0054] As is clear from the results shown in Table 2, the resin-coated metal foils obtained by Examples 1 to 3, which are the manufacturing method of this embodiment, had significantly reduced warping compared to the resin-coated metal foils of Comparative Examples 1 to 4. On the other hand, the resin-coated metal foils obtained by the methods of Comparative Examples 1 and 2, in which neither the (A) treatment nor the (B) treatment was performed, showed an insufficient reduction in the amount of warpage. Also, in Comparative Example 4, in which only the (B) treatment was performed three times without the (A) treatment, the reduction in the amount of warpage was also insufficient, which revealed that a combination of the (A) treatment and the (B) treatment is necessary to effectively reduce the amount of warpage.

[0055] [Manufacturing resin-coated metal foil] Example 4 The experiment was carried out in the same manner as in Example 3, except that the angle 7 of the tip of the curl straightening plate was changed to 70°, and a resin-coated metal foil H after warp straightening treatment was obtained. The amount of warp of each of the obtained resin-coated metal foils H was evaluated by the above method, and the results are shown in Table 3.

[0056] [Manufacturing resin-coated metal foil] Example 5 An experiment was carried out in the same manner as in Example 3, except that the cross-sectional shape of the tip of the curl correcting plate was changed to a circle with a diameter of 4 mm, and warp-straightened resin-coated metal foil I was obtained. The amount of warp of each of the obtained resin-coated metal foils I was evaluated by the above-mentioned method, and the results are shown in Table 3.

[0057] [Manufacturing resin-coated metal foil] Example 6 The experiment was carried out in the same manner as in Example 3, except that the pushing distance of the curl correction plate in the (B) treatment was changed to 16 mm, to obtain a resin-coated metal foil J after warp correction treatment. The amount of warp of each of the obtained resin-coated metal foils J was evaluated by the above-mentioned method, and the results are shown in Table 3.

[0058] [Manufacturing resin-coated metal foil] Example 7 In Example 3, an experiment was conducted in the same manner as in Example 3, except that the roll load in the (A) treatment was changed to 3.5 t and the pushing distance of the curl correction plate in the (B) treatment was changed to 13 mm, thereby obtaining resin-coated metal foils K after warp correction treatment. The results of evaluating the amount of warp of each of the obtained resin-coated metal foils K using the above method are shown in Table 3.

[0059] [Manufacturing resin-coated metal foil] Example 8 The experiment was carried out in the same manner as in Example 7, except that the pushing distance of the curl correction plate in the (B) treatment was changed to 19 mm, to obtain a resin-coated metal foil L after warp correction treatment. The amount of warp of each of the obtained resin-coated metal foils L was evaluated by the above-mentioned method, and the results are shown in Table 3.

[0060] [Table 3]

[0061] As is clear from the results shown in Table 3, the amount of warpage was also significantly reduced in the resin-coated metal foils obtained by the methods of Examples 4 to 8, which are the manufacturing methods of this embodiment. [Industrial Applicability]

[0062] The manufacturing method of this embodiment is excellent in productivity and can manufacture a resin-coated metal foil that is suppressed from warping. The resin-coated metal foil obtained by the manufacturing method of this embodiment is easy to handle and is therefore suitable for manufacturing semiconductor packages, such as semiconductor packages for electronic devices used in computers, information device terminals, and the like that process large amounts of data at high speed. [Explanation of symbols]

[0063] 1. Metal foil 2 Resin layer 3 Peeling layer 4 Carrier foil 5 rolls 5' Distance between rolls 5,5 6 Curl correction plate 7 Angle of the tip of the curl correction plate 8 Distance to push the curl correction plate toward the resin layer 9. Cross-sectional circle of the tip of the curl correction plate 10, 20 Resin-coated metal foil

Claims

1. A method for producing a resin-coated metal foil having a metal foil and a resin layer formed on one surface of the metal foil using a thermosetting resin composition, comprising: a warpage correction treatment for reducing warpage of the resin-coated metal foil, The warpage correction treatment includes the following treatment (A) and treatment (B): (A) Treatment: A treatment in which the resin-coated metal foil is pressed by passing it through a gap between a pair of opposing rolls, wherein the roll in contact with the metal foil is a resin roll and the roll in contact with the resin layer is a metal roll. (B) Treatment: Two rolls are placed apart, and the resin-coated metal foil is transported with the resin layer surface of the resin-coated metal foil facing the two rolls. A curl correcting plate is pressed between the two rolls and against the metal foil surface of the resin-coated metal foil, and the curl correcting plate is pressed toward the resin layer side.

2. 2. The method for producing a resin-coated metal foil according to claim 1, wherein in the treatment (B), the distance by which the curl correcting plate is pressed toward the resin layer is 1 to 25 mm.

3. 3. The method for producing a resin-coated metal foil according to claim 1, wherein in the treatment (B), the distance between the two rolls is 50 to 300 mm.

4. The method for producing a resin-coated metal foil according to any one of claims 1 to 3, wherein in the treatment (B), the cross-sectional shape of the tip of the curl correcting plate is convex or circular.

5. The method for producing a resin-coated metal foil according to any one of claims 1 to 4, wherein in the treatment (B), the conveying speed of the resin-coated metal foil is 1 to 15 m / min.

6. The method for producing a resin-coated metal foil according to any one of claims 1 to 5, wherein the metal foil has a thickness of 0.1 to 35 µm.

7. The method for producing a resin-coated metal foil according to any one of claims 1 to 6, wherein the resin layer has a thickness of 5 to 70 µm.

8. A method for producing a laminate, comprising a step of forming an insulating layer using a resin-coated metal foil obtained by the method for producing a resin-coated metal foil according to any one of claims 1 to 7.

9. A method for producing a printed wiring board, comprising the step of forming a wiring pattern on the laminate obtained by the method for producing a laminate according to claim 8.

10. A method for manufacturing a semiconductor package, comprising mounting a semiconductor element on a printed wiring board obtained by the method for manufacturing a printed wiring board according to claim 9.

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