TWI514945B - Method for manufacturing laminated board - Google Patents

Description

Method for manufacturing laminated board

The present invention relates to a method of manufacturing a laminated board.

In the method for producing a laminated board for a multilayer printed wiring board, a method of manufacturing a build-up method in which an insulating layer and a conductor layer are alternately overlapped on a circuit board belonging to a core layer is known. According to this method, when the insulating layer is formed, an adhesive film in which a thermosetting resin layer is formed on a plastic film is mainly used. The adhesive film is laminated on the core layer, and after peeling off the plastic film, the thermosetting resin is thermally cured to form an insulating layer.

For example, in the method for producing a laminated board described in the patent document 1 (Japanese Patent Laid-Open Publication No. 2000-228581), the vacuum-laminated layer is composed of a resin composition layer under heating and pressing conditions on the patterned circuit board. The first step of the film is followed; and a second step of applying heat and pressure from the support base film to smooth the surface of the resin composition layer adjacent to the support base film.

[Advanced technical literature] [Patent Literature]

Patent Document 1: Japanese Patent Laid-Open Publication No. 2000-228581

However, if the build-up material is formed using a thin layer of a thermosetting resin layer In the film, even if the smoothing step is performed as shown in Patent Document 1, the irregularities originating from the circuit pattern may remain on the surface of the laminated board. In particular, it is more obvious when the embossing is deeper in the circuit pattern trench or when the thickness of the layer is thinner. Further, in the hardening step, since it is generally applied without load, the unevenness of the layered material may occur along the unevenness of the circuit pattern. When there are residual irregularities on the surface of the laminated board, the thickness of the obtained laminated board may vary.

The present invention has been made in view of the above circumstances, and provides a method for producing a laminate which can stably produce a laminate having excellent surface smoothness.

According to the method for producing a laminated board according to the present invention, the circuit forming surface on which the core layer of the circuit forming surface is provided on one or both sides is formed, and the layer is made of thermosetting property under heat and pressure. a step of laminating the resin formed by the resin composition of the resin to obtain a layered body; and a smoothing step of smoothing the surface of the layered layer of the layered layer; and then heating the layered body to thermally harden the layered body The resin is further subjected to a hardening hardening step; wherein, in the stage of completion of the laminating step, the build-up material is subjected to a dynamic viscoelastic test according to a measurement range of 50 to 200 ° C, a temperature increase rate of 3 ° C/min, and a frequency of 62.83 rad / When the minimum value of the complex dynamic viscosity measured by sec is η1, η1 is 50 Pa‧s or more and 500 Pa‧s or less.

According to the invention, the multi-layering of the build-up material by the completion step of the lamination step When the state viscosity η1 is 50 Pa s or more, the fluidity of the thermosetting resin in the build-up material is not excessively increased, and therefore, the smoothing of the laminate can be performed while suppressing the bleeding of the thermosetting resin.

Further, according to the present invention, by setting the complex dynamic viscosity η1 of the build-up material at the completion stage of the build-up step to 500 Pa‧s or less, it is possible to ensure the moderate fluidity of the thermosetting resin in the build-up material, The surface of the laminate is smoothed. Therefore, it is possible to stably obtain a laminated board from which the unevenness of the circuit pattern does not remain on the surface.

Therefore, according to the present invention, a laminated board excellent in surface smoothness can be obtained stably.

According to the present invention, it is possible to provide a method for producing a laminated single-layer laminate which is excellent in surface smoothness and can be stably produced.

The above and other objects, features and advantages of the invention will be apparent from

Hereinafter, an embodiment of the present invention will be described using a schematic diagram. In the drawings, the same components are denoted by the same reference numerals, and their description is omitted.

(Manufacturing method of laminated board)

An outline of a method of manufacturing a laminated board of the present embodiment will be described. Fig. 1 is a cross-sectional view showing the manufacturing steps of the laminated plate 100 of the present embodiment.

First, the power of the core layer 102 of the circuit 101 has been formed on one or both sides. On the path forming surface 103, a build-up material 200 formed of a resin composition containing a thermosetting resin 201 is laminated under heat and pressure to obtain a laminate (layering step). Next, smoothing (smoothing step) of the surface of the build-up layered material 200 is performed by, for example, hot pressing of a pair of opposing metal members. Then, the laminated body is heated and the thermosetting resin 201 is further cured (curing step), whereby the laminated board 100 of the present embodiment can be obtained.

Here, the build-up layer 200 in the completion step of the lamination step is subjected to a dynamic viscoelasticity test, and the minimum value η1 of the complex dynamic viscosity obtained by the measurement range of 50 to 200 ° C, the temperature increase rate of 3 ° C / min, and the frequency of 62.83 rad / sec is 50 Pa. ‧ s or more, preferably 70 Pa ‧ or more, more preferably 100 Pa ‧ s or more When the complex dynamic viscosity η1 is equal to or higher than the lower limit value, the fluidity of the thermosetting resin 201 in the build-up material 200 does not become excessively large, so that the bleed out of the thermosetting resin 201 can be suppressed in the smoothing step. , you can smoothly smooth the laminate.

Furthermore, the build-up layer 200 of the completion step of the build-up step is subjected to a dynamic viscoelasticity test, and the minimum value η1 of the complex dynamic viscosity obtained by the measurement range of 50 to 200 ° C, the temperature increase rate of 3 ° C / min, and the frequency of 62.83 rad / sec is 500 Pa. ‧ s or less, preferably 450 Pa ‧ or less, more preferably 400 Pa ‧ or less By setting the complex dynamic viscosity η1 to be equal to or less than the above upper limit value, it is possible to smoothly smooth the surface of the laminated body while ensuring the fluidity of the thermosetting resin 201 in the build-up material 200. Therefore, the laminated board 100 from which the unevenness of the circuit 101 does not remain on the surface can be stably obtained.

Further, after the completion of the lamination step and before the smoothing step is performed, the buildup material 200 may be reacted due to heat remaining in the laminate. Therefore, the above-mentioned "layering step completion stage" refers to a state just before entering the smoothing step. Therefore, the build-up material 200 does not need to satisfy the above-described complex dynamic viscosity η1 immediately after the step of laminating, as long as the above-mentioned complex dynamic viscosity η1 can be satisfied until the smoothing step is to be performed.

In addition, the complex dynamic viscosity η1 is obtained by cutting out a resin composition containing a thermosetting resin from the layer 300 on the surface of the laminated body and using it as a measurement sample, and then measuring it using a dynamic viscoelasticity measuring apparatus.

Next, each material constituting the laminate 100 of the present embodiment will be described.

(core layer)

The core layer 102 refers to one or both sides of a substrate such as a glass epoxy substrate, a metal substrate, a polyester substrate, a polyimide substrate, a BT resin substrate, a thermosetting polyphenylene ether substrate, etc., and is patterned. The circuit forms a sheet-like shape of the surface 103. Further, the core layer 102 also covers the inner layer circuit substrate which further forms the intermediate product of the layer 300 and the circuit 101.

The manufacturing method of the core layer 102 is not particularly limited. For example, a core layer provided with a metal foil on both sides is used, and a hole drilling machine is used to cut a hole in a predetermined place, and then electroless plating is used to achieve double-sided conduction of the core layer. Then, the circuit 101 is formed by etching the metal foil. Further, it is preferable that the inner layer circuit portion performs a roughening process such as a blackening process. Also, the opening portion can utilize, for example, a conductor paste or The resin paste is properly buried.

(additional layer)

The build-up material 200 is an insulating resin sheet mainly composed of a thermosetting resin layer. Further, the build-up material 200 of the present embodiment does not include a prepreg obtained by immersing a thermosetting resin on a fiber base material.

The method for producing the build-up material 200 is not particularly limited, and for example, the resin composition P can be dissolved in a solvent to prepare a resin varnish V, and the resin varnish V can be applied onto the base film, and the solvent can be dried. A well-known method is used for production. The obtained insulating resin sheet can be kept in its original state, or a release film can be further laminated on the surface of the thermosetting resin layer, and then wound up in a roll shape and stored.

The method of applying the resin composition P to the base film can be, for example, a method of immersing the base film in the resin varnish V, a method of applying the resin varnish V to the base film by using various coaters, or A method of blowing the resin varnish V onto the substrate film by spraying or the like. Among these, a method of applying the resin varnish V to the base film by various coaters is preferred. Thereby, the insulating resin sheet can be continuously manufactured using a known coating apparatus.

The resin composition P contains (A) an epoxy resin. (A) The epoxy resin may, for example, be a bisphenol A epoxy resin, a bisphenol F epoxy resin, a bisphenol S epoxy resin, a bisphenol E epoxy resin, or a bisphenol M epoxy resin. , bisphenol type epoxy resin such as bisphenol P type epoxy resin, bisphenol Z type epoxy resin; phenolic epoxy resin such as phenol novolac type epoxy resin and cresol novolac type epoxy resin; biphenyl type ring Aromatic resin such as oxygen resin, biphenyl aralkyl epoxy resin; naphthalene epoxy resin, fluorene epoxy resin, phenoxy epoxy resin, dicyclopentadiene epoxy resin, An epoxy resin such as an olefin epoxy resin, an adamantane epoxy resin or a fluorene epoxy resin. One of these may be used alone or two or more of them may be used in combination.

The content of the epoxy resin (A) is not particularly limited, but is preferably 15% by mass or more and 80% by mass or less based on the entire resin composition P. More preferably, it is 25 mass% or more and 50 mass% or less. Further, when a liquid epoxy resin such as a liquid bisphenol A type epoxy resin or a bisphenol F type epoxy resin is used in combination, the coating property to the base film can be improved, which is preferable. The content of the liquid epoxy resin is preferably 2% by mass or more and 18% by mass or less based on the entire resin composition P. Further, when a solid bisphenol A type epoxy resin or a bisphenol F type epoxy resin is used in combination, the adhesion to the conductor can be improved.

Further, the resin composition P may contain a thermosetting resin other than an epoxy resin such as a melamine resin, a urea resin or a cyanate resin, and a cyanate resin is preferably used in combination. The type of the cyanate resin is not particularly limited, and examples thereof include a phenolic cyanate resin, a bisphenol A type cyanate resin, a bisphenol E type cyanate resin, and a tetramethyl bisphenol F type cyanate. A bisphenol type cyanate resin such as an ester resin. Among these, a phenol novolac type cyanate resin is preferred from the viewpoint of low thermal expansion property. In addition, one type or two or more types of other cyanate resins may be used in combination, and are not particularly limited. The cyanate resin preferably accounts for 8 mass% or more and 20 mass% or less of the entire resin composition P.

The resin composition P preferably contains (B) an inorganic filler. (B) Inorganic filler For example, talc, calcined clay, uncalcined clay, mica, glass, etc.; oxides such as titanium oxide, aluminum oxide, cerium oxide, molten cerium oxide; carbonic acid such as calcium carbonate, magnesium carbonate, hydrotalcite, etc. Salt; hydroxides such as aluminum hydroxide, magnesium hydroxide, calcium hydroxide; sulfates or sulfites such as barium sulfate, calcium sulfate, calcium sulfite; zinc borate, barium metaborate, aluminum borate, calcium borate, sodium borate And other borate; nitride such as aluminum nitride, boron nitride, tantalum nitride, carbon nitride; titanate such as barium titanate or barium titanate. One of these may be used alone or two or more of them may be used in combination.

Among these, particularly preferred cerium oxide is a molten cerium oxide (especially spherical molten cerium oxide) from the viewpoint of excellent low thermal expansion property. The shape is a crushed shape or a spherical shape. However, in order to ensure the coating property to the base film, and to reduce the melt viscosity of the resin composition P, for example, a spherical cerium oxide or the like can be used, and a use method for the purpose of blending can be used. .

(B) The average particle diameter of the inorganic filler is not particularly limited, but is preferably 0.01 μm or more and 3 μm or less, more preferably 0.02 μm or more and 1 μm or less. When the particle diameter of the (B) inorganic filler is 0.01 μm or more, the varnish can be made to have a low viscosity, and the resin composition P can be favorably applied to the base film. In addition, when it is 3 μm or less, (B) inorganic filler precipitation or the like can be suppressed in the varnish. The average particle diameter can be measured by, for example, a particle size distribution meter (manufactured by Shimadzu Corporation, product name: laser diffraction type particle size distribution measuring apparatus SALD series).

Further, (B) the inorganic filler is not particularly limited, and an average particle may be used. The inorganic filler having a single-dispersion diameter may be an inorganic filler having an average particle diameter of polydisperse. Further, one type or two or more types of inorganic fillers having an average particle diameter of monodisperse and/or polydisperse may be used in combination.

Further, spherical cerium oxide (especially spherical molten cerium oxide) having an average particle diameter of 3 μm or less, and spherical molten cerium oxide having an average particle diameter of 0.02 μm or more and 1 μm or less is more preferable. Thereby, the filling property of (B) inorganic filler can be improved.

(B) The content of the inorganic filler is not particularly limited, and is preferably 2% by mass or more and 70% by mass or less, and more preferably 5% by mass or more and 60% by mass or less based on the entire resin composition P. When the content is within the above range, in particular, it can be low in thermal expansion and low in water absorption.

The resin composition P is not particularly limited, and a (C) coupling agent is preferably used. (C) The coupling agent improves the heat resistance, particularly the solder heat resistance after moisture absorption, by improving the interfacial wettability between the (A) epoxy resin and the (B) inorganic filler.

The (C) coupling agent can be used as it is, and it is preferable to use it from an epoxy decane coupling agent, a cationic decane coupling agent, an amino decane coupling agent, a titanate coupling agent, and a polyoxyl One or more types of coupling agents are selected among the type coupling agents. Thereby, the wettability between the interface with the (B) inorganic filler can be improved, and thereby the heat resistance can be further improved.

(C) The amount of the coupling agent to be added is not particularly limited as long as it depends on the specific surface area of the inorganic filler (B), and is preferably 0.02% by mass or more and 3% by mass based on 100 parts by mass of the (B) inorganic filler. The following, more preferably 0.1% by mass The above and 2% by mass or less. By setting the content to 0.02% by mass or more, the inorganic filler (B) can be sufficiently coated, and the heat resistance can be improved. When the amount is 3% by mass or less, the reaction can be favorably performed, and the bending strength and the like can be prevented from being lowered.

As the resin composition P, (D) a phenol-based curing agent can be further used. Examples of the phenolic curing agent include a phenol novolak resin, an alkylphenol phenol resin, a bisphenol A phenol resin, a dicyclopentadiene type phenol resin, an XYLOCK type phenol resin, a terpene modified phenol resin, and a polyvinyl phenol. Those skilled in the art may use these two or more types alone or in combination.

The blending amount of the (D) phenol curing agent is preferably 0.1 or more and 1.0 or less in an equivalent ratio (phenolic hydroxyl equivalent/epoxy equivalent) to the (A) epoxy resin. Thereby, there is no unreacted phenolic hardener remaining, and the moisture absorption heat resistance is improved. When the resin composition P is used in combination with an epoxy resin and a cyanate resin, it is more preferably in the range of 0.2 or more and 0.5 or less. The reason is that the phenol resin not only functions as a hardener but also promotes hardening between the cyanate group and the epoxy group.

In the resin composition P, (E) a curing catalyst may be used as needed. (E) A hardening catalyst system can use a well-known thing. For example: zinc naphthenate, cobalt naphthenate, tin octoate, cobalt octoate, cobalt (II) acetoacetate, cobalt (III) such as acetylacetate (III); triethylamine, tributylamine a tertiary amine such as diazabicyclo[2,2,2]octane; 2-phenyl-4-methylimidazole, 2-ethyl-4-methylimidazole, 2-ethyl-4-B Imidazoles such as imidazole, 2-phenyl-4-methylimidazole, 2-phenyl-4-methyl-5-hydroxyimidazole, 2-phenyl-4,5-dihydroxyimidazole; phenol, bisphenol A Phenol and other phenols a compound; an organic acid such as acetic acid, benzoic acid, salicylic acid or p-toluenesulfonic acid, or the like, or a mixture thereof. The curing catalyst may be used alone or in combination of two or more of these derivatives.

The content of the (E) curing catalyst is not particularly limited, and is preferably 0.05% by mass or more, and more preferably 0.2% by mass or more based on the entire resin composition P. When the content of the curing catalyst is at least the above lower limit value, the build-up material 200 having a minimum value η1 of the complex dynamic viscosity measured by the dynamic viscoelasticity test of 50 Pa‧s or more can be more efficiently obtained. The above dynamic viscoelasticity test is a measurement range of 50 to 200 ° C, a temperature increase rate of 3 ° C / min, and a frequency of 62.83 rad / sec. Moreover, the hardening can be sufficiently promoted.

In addition, the content of the curing catalyst is not particularly limited, but is preferably 5% by mass or less, and more preferably 2% by mass or less based on the entire resin composition P. By setting it as the said upper limit or less, it is more efficient to acquire the build-up material 200 which the minimum value of the complex dynamic viscosity η1 measured by the dynamic viscoelasticity test is 500 Pa*s or less. The above dynamic viscoelasticity test is a measurement range of 50 to 200 ° C, a temperature increase rate of 3 ° C / min, and a frequency of 62.83 rad / sec. Further, it is possible to prevent the preservation property of the build-up material 200 from being lowered.

The resin composition P may also be used in combination such as: phenoxy resin, polyimine resin, polyamidamine resin, polyamide resin, polyphenylene ether resin, polyether oxime resin, polyester resin, polyethylene resin , thermoplastic resin such as polystyrene resin; polystyrene thermoplastic elastomer such as styrene-butadiene copolymer or styrene-isoprene copolymer; polyolefin-based thermoplastic elastomer, polyamine Thermoplastic elastomers such as elastomers and polyester elastomers; dienes such as polybutadiene, epoxy modified polybutadiene, acrylic modified polybutadiene, and methacrylic modified polybutadiene Elastomer. Among these, a heat-resistant polymer resin such as a phenoxy resin, a polyimide resin, a polyamide amide resin, a polyamide resin, a polyphenylene ether resin, or a polyether oxime resin is preferable. Thereby, the thickness of the buildup material is excellent, and it is excellent in heat resistance and fine wiring insulation as a wiring board. Further, in the resin composition P, if necessary, a pigment, a dye, an antifoaming agent, a leveling agent, an ultraviolet absorber, a foaming agent, an antioxidant, a flame retardant, an ion trapping agent, etc. may be added in addition to the above components. Additions other than those.

The solvent used in the resin varnish V preferably has a good solubility in the resin component in the resin composition P, and a poor solvent can also be used insofar as it does not cause an adverse effect. The solvent which is in good solubility can be, for example, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, cyclopentanone, tetrahydrofuran, dimethylformamide, dimethylacetamide, dimethyl hydrazine, ethyl Glycol, celluloid, carbitol, and the like.

The solid content of the resin varnish V is not particularly limited, and the solid content of the resin composition P is preferably 20% by mass or more and 80% by mass or less, more preferably 50% by mass or more and 70% by mass or less. Thereby, the coatability of the resin varnish V to the base film can be further improved.

After the resin composition P is applied onto the base film, the temperature at which the solvent is dried is not particularly limited. For example, it can be dried at 90° C. or higher and 220° C. or lower.

The thickness of the build-up material 200 is preferably 50 μm or less. Especially in the case of 30 μm or less, because it is easier to produce a concave from the circuit pattern on the surface of the laminated board. Therefore, the method of manufacturing the laminated board of the present embodiment is more effective. Here, the thickness of the build-up material 200 indicates the thickness of the thermosetting resin layer formed on the base film, and does not include the thickness of the base film.

The base film is not particularly limited, and a plastic film or a metal foil such as polyester such as polyethylene terephthalate (PET) or polyethylene naphthalate (PEN); polycarbonate (PC) can be used. , acrylic resin (PMMA), cyclic polyolefin, cellulose triacetate (TAC), polyether oxime (PES), polyether ketone, polyimide, metal foil such as copper foil or aluminum foil. The thickness of the base film is not particularly limited, but is generally 10 μm or more and 150 μm or less. Further, the base film may be subjected to a matting treatment, a corona treatment, a release treatment, or the like.

The build-up material 200 may also be laminated in a plurality of layers via a metal foil or film. Examples of the metal foil include copper and copper alloys, aluminum and aluminum alloys, silver and silver alloys, gold and gold alloys, zinc and zinc alloys, nickel and nickel alloys, tin and tin alloys, and iron. And metal foils such as iron-based alloys. Among these, copper foil is preferred.

Next, each step of the method of manufacturing the laminated board will be described in detail.

(layering step)

First, it is preferable to prepare the build-up material 200 which has been wound in a roll shape and convey it to the laminator together with the sheet-like core layer 102. Preferably, the laminating machine is provided with a pair of elastic members facing each other, and the core layer 102 and the build-up material 200 are sandwiched by the elastic member, and are laminated by heating and pressurizing the elastic member. In this case, it is preferable to use a laminate having an elastic member such as a heat insulating rubber. The machine is pressed and pressed through an elastic member. The elastic member is flexible because the uneven shape of the circuit 101 formed on the core layer can be traced, so that the core layer 102 and the build-up material 200 can be more encrypted.

The laminating machine is preferably a laminator (vacuum laminator) which performs heating and pressurization under vacuum. As the elastic member, for example, a plate-like or rolled rubber can be used.

The heating temperature is not particularly limited, but is preferably 80 ° C or higher, more preferably 90 ° C or higher. When the value is at least the above lower limit value, the build-up material 200 having a complex dynamic viscosity η1 of 50 Pa‧s or more as measured by the dynamic viscoelasticity test can be more efficiently obtained. Further, the heating temperature is preferably 160 ° C or lower, more preferably 140 ° C or lower. When the value is at most the above upper limit value, the build-up material 200 having a complex dynamic viscosity η1 of 500 Pa·s or less as measured by the dynamic viscoelasticity test can be more efficiently obtained.

The heating time is not particularly limited, but is preferably 10 seconds or longer, more preferably 30 seconds or longer. By setting it as the said lower limit or more, the build-up material 200 of the complex dynamic viscosity η1 measured by the dynamic viscoelasticity test up to 50 Pa‧s or more can be obtained more efficiently. Further, the heating time is not particularly limited, but is preferably 500 seconds or shorter, more preferably 300 seconds or shorter. By setting it as the said upper limit or less, the build-up material 200 of the complex dynamic viscosity η1 measured by the dynamic viscoelasticity test of 500 Pa*s or less is obtained more efficiently.

The pressure is preferably in a range of 0.4 MPa or more and 1.5 MPa or less.

The above lamination step can be carried out using a commercially available vacuum laminator. For example, a vacuum-pressure laminated layer of CPV300 manufactured by Nichigo Morton Co., Ltd. can be used. Machine, or its equivalent.

(smoothing step)

After the lamination step, the thermosetting resin 201 forming the build-up layer 200 is softened, and the circuit 101 formed on the core layer 102 is traced to be uneven. Here, the buildup layer 300 and the core layer 102 are subjected to hot pressing by a pair of metal members opposed to each other, thereby smoothing the laminated body.

The smoothing step is performed by heating and pressurizing the laminated body via a metal member such as a heated SUS mirror plate under atmospheric pressure.

Here, the build-up material 200 in the completion stage of the smoothing step is subjected to a dynamic viscoelasticity test to obtain a minimum value η2 of the complex dynamic viscosity according to a measurement range of 50 to 200 ° C, a temperature increase rate of 3 ° C/min, and a frequency of 62.83 rad/sec. Hereinafter, the case of "complex dynamic viscosity η2" is simply referred to as η2≧η1 × 1.1. By satisfying the above relationship, it is less likely to cause expansion of the laminate or the like in the subsequent curing step, and a laminated sheet having more excellent surface smoothness can be obtained. Further, by satisfying the above relationship, the hardening step can be performed more efficiently.

Furthermore, in the build-up layer 200 at the completion stage of the smoothing step, the minimum value η2 of the complex dynamic viscosity measured by the dynamic viscoelasticity test is preferably 520 Pa‧s or more, more preferably 550 Pa‧s or more, and particularly good 580 Pa‧ s above. When the complex dynamic viscosity η2 is equal to or higher than the above lower limit value, expansion of the laminate or the like is less likely to occur in the subsequent curing step, and a laminated sheet having more excellent surface smoothness can be obtained. Further, by satisfying the above relationship, the hardening step can be performed more efficiently.

Further, in the build-up layer 200 at the completion stage of the smoothing step, the complex dynamic viscosity η2 measured by the dynamic viscoelasticity test is preferably 10,000 Pa‧s or less, more preferably 5,000 Pa‧s or less. When the complex dynamic viscosity η2 is equal to or less than the above upper limit value, a laminated board having more excellent storage properties can be obtained.

In addition, the complex dynamic viscosity η2 is obtained by cutting out a resin composition containing a thermosetting resin from the layer 300 on the surface of the laminated body and using it as a measurement sample, and then measuring it using a dynamic viscoelasticity measuring apparatus.

Such a smoothing step can be carried out using a commercially available hot press device, and for example, a hot press device of CPV300 manufactured by Nichigo Morton Co., Ltd., or the like can be used.

The heating temperature is not particularly limited, but is preferably 80 ° C or higher, more preferably 90 ° C or higher. When it is set to the above lower limit value, the buildup step 200 can be more efficiently obtained, and the build-up material 200 having a complex dynamic viscosity η2 of 520 Pa·s or more measured by a dynamic viscoelasticity test can be obtained. Further, the heating temperature is preferably 180 ° C or lower, more preferably 170 ° C or lower. When the value is at most the above upper limit value, the build-up material 200 having a complex dynamic viscosity η2 of 10,000 Pa·s or less as measured by the dynamic viscoelasticity test can be more efficiently obtained.

The heating time is not particularly limited, but is preferably 10 seconds or longer, more preferably 30 seconds or longer. When it is set to the above lower limit value, the buildup step 200 can be more efficiently obtained, and the build-up material 200 having a complex dynamic viscosity η2 of 520 Pa·s or more measured by a dynamic viscoelasticity test can be obtained. Further, the heating time is not particularly limited, but is preferably 500 seconds or shorter, more preferably 300 seconds or shorter. By setting Below the above upper limit value, it is possible to more efficiently obtain the finishing step of the smoothing step, and the build-up material 200 having a complex dynamic viscosity η2 of 10,000 Pa‧s or less as measured by the dynamic viscoelasticity test.

The pressure is preferably in a range of 0.4 MPa or more and 1.5 MPa or less.

Further, it is preferable that the total lamination step time of the evacuation and the pressurization time is equal to the smoothing step time. Accordingly, since the linear velocity of the conveyed laminate can be made constant, the lamination step and the smoothing step can be performed continuously and efficiently.

(second smoothing step)

In the method for producing a laminated board according to the present embodiment, the second smoothing step may be further performed between the smoothing step (hereinafter also referred to as "first smoothing step") and the hardening step, and further may be further performed. The surface of the build-up material 200 is smoothed while reacting the thermosetting resin. Thereby, the reaction of the thermosetting resin can be further progressed, and the surface of the laminated plate 100 can be prevented from being swollen by volatilization of unreacted components in the subsequent step.

Further, by separately performing the smoothing step, it is not necessary to set the heating temperature and pressure to severe conditions which cause the thermosetting resin to be hardened and hardened. Therefore, smoothing of the surface of the laminated body can be performed while suppressing generation of residual stress of the laminated body under appropriate conditions. Thereby, the amount of generation of residual stress can be suppressed, and deterioration of heat resistance and moisture resistance reliability can be suppressed.

Furthermore, the warpage of the laminated board may occur due to the amount of residual stress generated, especially after the step of forming the laser interlayer, which may occur remarkably. If the laminate is warped, the warpage of the semiconductor package will become large, resulting in a drop in mounting yield. low. Further, by separately performing the smoothing step, the residual stress generated in the laminated plate can be further suppressed, so that warpage can be suppressed, and a laminated board having more excellent reliability can be obtained.

The number of times of the second smoothing step is not particularly limited, and may be performed twice or more in accordance with the surface state of the laminated body. By performing two or more times, a laminated board which is more excellent in surface smoothness can be obtained.

The second smoothing step may further change the conditions such as pressure or temperature while applying pressure to the laminated body while maintaining the first smoothing step, or may be released after the first smoothing step. It is only carried out after the pressure is applied by the laminate. In particular, it is preferred that the second smoothing step be performed after the pressure applied to the laminate is released after the first smoothing step.

The second smoothing step is not particularly limited and may be carried out in the same manner as the first smoothing step, or may be carried out in accordance with a different method. Different methods are used as the method of using the belt conveyor shown below.

First, the laminated body after the first smoothing step is placed on a belt conveyor. Next, a hammer such as a metal member is placed on the laminated body, and the laminated body is pressurized. Next, the belt conveyor is operated, and heating is performed while the laminate is pressurized while passing through the inside of the drying furnace.

The metal member to be placed on the laminated body is not particularly limited as long as it has the quality of the laminated body, and is preferably a stainless steel plate or the like from the viewpoint of corrosion resistance and ease of availability.

The mass per unit area of the metal member placed on the laminated body is not particularly limited, but is preferably 0.01 kg/cm ² or more and 15 kg/cm ² or less. If it is a mass of the above range, a laminate having more excellent surface smoothness can be obtained.

Further, the mass per unit area can be adjusted by the thickness and the number of sheets of the metal member, and the hammer can be further placed on the metal member for adjustment.

The heating temperature in the second smoothing step is not particularly limited, and it is preferred that the first smoothing step be higher than the temperature in the range of 10 ° C or more and 100 ° C or less. By setting the temperature higher than the first smoothing step, the surface of the build-up material 200 can be more efficiently smoothed while further promoting the reaction of the thermosetting resin.

Such a second smoothing step can be carried out using a commercially available apparatus, and for example, a hot forming press manufactured by Beichuan Seiki Co., Ltd., a hot press device manufactured by a company, a heating press manufactured by MIKADO TECHNOS, and a Held company can be used. The belt press device, the belt press device manufactured by Sandvik, or the equivalent.

(hardening step)

After the smoothing step, the thermosetting resin 201 forming the build-up material 200 is further heated and hardened. The curing temperature is not particularly limited. For example, it can be cured in a range of from 100 ° C to 250 ° C, preferably from 150 ° C to 200 ° C. The hardening step is usually carried out by heating the laminate at atmospheric pressure.

In the hardening step of the present embodiment, it is preferred that the temperature of the laminate is gradually increased from the initial temperature to the highest temperature. In this way, it is possible to suppress the laminate The surface is swelled and the laminated body generates residual stress, and the thermosetting resin 201 forming the build-up material 200 is cured. By suppressing the expansion on the surface of the laminated body, a laminated board having more excellent surface smoothness can be obtained.

Furthermore, the warpage of the laminated board may occur depending on the amount of residual stress generated, particularly after the step of forming the laser interlayer, the warpage may be apparent. If the laminated board is warped, the warpage of the semiconductor package becomes large, resulting in a decrease in mounting yield. In the hardening step, by gradually increasing the temperature of the laminated body from the initial temperature to the highest temperature reached, residual stress can be suppressed from occurring in the laminated plate, so that warpage can be suppressed, and a laminated board having more excellent reliability can be obtained.

The initial temperature is not particularly limited on the premise that the temperature of the rapid hardening reaction does not occur. After the smoothing step, the hardening step is carried out after cooling the laminate body temperature to around room temperature, and the initial temperature is preferably around room temperature. For example, it is 0 ° C or more and 40 ° C or less.

When the hardening step is followed by the smoothing step, the hardening step may be started after the laminate body temperature is cooled to near room temperature. In this case, it is preferably 40 ° C or higher, more preferably 60 ° C or higher. When the thickness of the laminated body is increased and the residual stress is generated in the laminated body, the curing of the thermosetting resin layer can be performed more efficiently.

Further, the initial temperature is not particularly limited, but is preferably 90 ° C or lower, more preferably 80 ° C or lower. When the temperature is less than or equal to the above-described upper limit, the temperature rise of the laminate is less likely to occur, and the hardening of the thermosetting resin can be promoted while suppressing the expansion of the surface of the laminate and the generation of residual stress in the laminate.

The maximum reaching temperature is not particularly limited, but is preferably 90 ° C or higher, more preferably 120 ° C or higher. By setting it as the said lower limit or more, it can fully accelerate hardening.

Further, the maximum reaching temperature is not particularly limited, but is preferably 230 ° C or lower, more preferably 200 ° C or lower. By setting it as the said upper limit or less, the hardening of the thermosetting resin can be performed more efficiently by suppressing the expansion of the surface of a laminated body and the residual stress generate|occur|produce of a laminated body.

The average temperature rise rate from the initial temperature to the highest temperature reached is not particularly limited as long as it does not cause a rapid hardening reaction, and is preferably 1 ° C / min or more, more preferably 3 ° C / Min or above. By setting it as the said lower limit or more, it can improve the hardening reaction more efficiently.

In addition, the average temperature increase rate from the initial temperature to the highest temperature reached is not particularly limited, but is preferably 15° C./min or less, and more preferably 12° C./min or less. When the thickness is equal to or less than the above-described upper limit, it is possible to suppress the occurrence of swelling of the surface of the laminated body and the generation of residual stress in the laminated body, and it is possible to more effectively promote the hardening of the thermosetting resin.

Further, the average temperature increase rate from the initial temperature to the highest temperature reached can be calculated from the time when the surface temperature of the laminate reaches the highest temperature reached, and the difference between the highest temperature and the initial temperature. Here, the surface temperature of the laminated body can be measured, for example, by embedding a thermocouple in the laminated body.

Further, the temperature increase rate from the initial temperature to the highest temperature of arrival may be constant, and may be changed by at least two stages or more. It is more efficient to promote the expansion of the surface of the laminate and the generation of residual stress in the laminate. In the hardening step, it is preferred to set the initial temperature increase rate of the hardening step to be slow, and to accelerate the temperature increase rate a little with the progress of hardening.

The heating device for the laminate in the hardening step is not particularly limited, and a known heating method can be used. For example, a heating drying device such as hot air drying, far infrared heating, high frequency induction heating, or the like can be used.

The heating method of the laminate is not particularly limited, and the laminate may be continuously heated by a horizontal conveyance type heating and drying apparatus, or the laminate may be placed in a heating and drying apparatus and heated in a batch.

The method of gradually increasing the temperature of the laminate from the initial temperature to the maximum temperature is not particularly limited, and can be, for example, the following method. For example, when the laminated body is passed through a horizontal transfer type heating and drying apparatus and is continuously heated, it can be carried out using a heating and drying apparatus having two or more units. The temperature of the heated laminate can be changed stepwise by sequentially increasing the temperature from the first unit through which the laminate passes. Therefore, the temperature of the laminated body can be changed stepwise from the initial temperature to the highest reaching temperature.

Further, when the laminated body is statically placed in the heating and drying device and heated in a batch manner, for example, by setting the temperature rise distribution of the heating and drying device, the temperature of the laminated body can be gradually increased from the initial temperature to the highest temperature. temperature. In addition, even if the laminated body in the initial temperature state is placed in the heating and drying device set to the highest temperature in advance, the entire laminated body is uniformly heated, and the temperature of the laminated body can be gradually increased from the initial temperature to the highest temperature. .

The hardening time is not particularly limited, but is preferably 30 minutes or more, and more preferably 45 minutes or more. By setting it as the said lower limit or more, it can fully accelerate hardening.

Further, the curing time is not particularly limited, but is preferably 75 minutes or shorter, more preferably 60 minutes or shorter. When it is set to the above-mentioned upper limit or less, it is possible to more effectively promote the hardening of the thermosetting resin while suppressing the expansion of the surface of the laminated body and the generation of residual stress in the laminated body.

Further, the step of lowering the temperature of the laminate is preferably such that the temperature of the laminate is gradually lowered from the highest temperature. Thereby, the temperature of the laminated body can be returned to room temperature while suppressing the generation of residual stress in the laminated body.

(laser layer formation step)

Next, a laser such as a carbon dioxide gas laser or a YAG laser is applied to the hardened layer 300 to form a via hole. The resin residue or the like after the laser irradiation is preferably removed by using an oxidizing agent such as permanganate or dichromate. Further, the surface of the smoothing layer 300 can be roughened at the same time, and the adhesion of the circuit formed by metal plating can be improved. The build-up layer 300 can uniformly apply a fine uneven shape in the above roughening treatment. Moreover, since the smoothness of the surface of the layer 300 is improved, a fine wiring circuit can be formed with high precision. Then, a solder resist is formed on the outermost layer, and the connection electrode portion for mounting the semiconductor element is exposed by exposure and development, and then nickel plating treatment is performed, and the laminated board is obtained by cutting to a predetermined size.

According to the method for producing a laminated board of the present embodiment, since the residual stress generated in the laminated board is suppressed, even if the laser layer forming step is performed, The obtained laminate is still less prone to warpage. Therefore, a laminated board which suppresses warpage can be obtained.

(semiconductor package)

Next, the semiconductor package will be described.

The semiconductor package can be fabricated by mounting a semiconductor element on the above laminated board. The method of mounting the semiconductor element and the sealing method are not particularly limited. For example, it can be manufactured in the following manner.

First, alignment between the electrode portion for connection on the build-up wiring board and the solder bump of the semiconductor element is performed using, for example, a flip chip bonder. Next, the solder bumps are heated to a temperature higher than the melting point using, for example, an IR reflow device, a hot plate, or another heating device, and the multilayer printed wiring board and the solder bumps are joined by fusion bonding. Finally, a liquid sealing resin is filled between the laminated wiring board and the semiconductor element, and then hardened to obtain a semiconductor package.

The embodiments of the present invention have been described above with reference to the drawings, but these are merely examples of the present invention, and various configurations other than the above may be employed.

For example, although FIG. 1 shows a case where the build-up layer is a single layer, the layer may have a structure in which two or more layers are laminated on one side or both sides of the core layer.

(Example)

Hereinafter, the present invention will be described using the examples and comparative examples, but the present invention is not limited thereto.

The raw materials used in the examples and comparative examples are as follows.

Inorganic filler: spherical cerium oxide (SO-25R, Admatechs, average particle size 0.5 μm)

Epoxy resin: biphenyl aralkyl type phenolic epoxy resin (NC-3000, manufactured by Nippon Kayaku Co., Ltd.)

Epoxy resin: Dicyclopentadiene type phenolic epoxy resin (made by DIC Corporation, HP-7200L)

Cyanate resin: phenolic cyanate resin (Primaset PT-30 manufactured by LONZA)

Epoxy resin: bisphenol A type liquid epoxy resin (manufactured by Mitsubishi Chemical Corporation, jER-828EL)

Epoxy resin: bisphenol F type liquid epoxy resin (manufactured by Mitsubishi Chemical Corporation, jER-807)

Phenol hardener: phenolic phenol resin (made by DIC, TD-2090-60M, 60% (w/v) methyl ethyl ketone solution)

Phenoxy resin: manufactured by Mitsubishi Chemical Corporation, YX6954BH30, 30% (w/v) methyl ethyl ketone / cyclohexanone solution)

Polyvinyl acetal resin: KS-10 (hydroxyl 25 mol%) manufactured by Sekisui Chemical Co., Ltd.

Hardening catalyst: 2-ethyl-4-methylimidazole (2E4MZ manufactured by Shikoku Chemicals Co., Ltd.)

Coupling agent: N-phenyl-3-aminopropyltrimethoxydecane (manufactured by Shin-Etsu Chemical Co., Ltd., KBM-573)

(Example 1) (1) Modification of resin varnish

30.0 parts by mass of a dicyclopentadiene type epoxy resin (manufactured by DIC Corporation, HP-7200L) of an epoxy resin, 3.0 parts by mass of a bisphenol F type liquid epoxy resin (manufactured by Mitsubishi Chemical Corporation, jER807), cyanate ester 14.0 parts by mass of a resin phenol novolac type cyanate resin (Primaset PT-30, manufactured by LONZA Co., Ltd.) and YX6954BH30 manufactured by Mitsubishi Chemical Corporation as a phenoxy resin, 3.1 parts by mass in terms of solid content, and imidazole of a curing catalyst (four 0.15 parts by mass of 2E4MZ) manufactured by Kokusai Kasei Co., Ltd., and dissolved by a mixed solvent of methyl ethyl ketone and cyclohexanone for 60 minutes. Further, 0.05 parts by mass of N-phenyl-3-aminopropyltrimethoxydecane (manufactured by Shin-Etsu Chemical Co., Ltd., KBM-573), and spherical cerium oxide (inorganic filler) (manufactured by Admatech Co., Ltd.) SO-25R, an average particle diameter of 0.5 μm), 49.7 parts by mass, was stirred for 10 minutes by a high-speed stirring device to obtain a resin varnish having a solid content of 65%.

(2) Production of Resin Sheet A

The obtained resin varnish was applied to one surface of a PET (polyethylene terephthalate) film having a thickness of 36 μm using a batch roll coater apparatus. This was dried by a drying apparatus at 160 ° C for 3 minutes to obtain a resin sheet A having a resin thickness (corresponding to the thickness of the build-up material) of 40 μm.

(3) Lamination step

A laminate was produced from the resin sheet A using a two-stage buildup laminator CVP300 manufactured by Nichigo Morton Co., Ltd. Specifically, an ELC-4785GS-B (manufactured by SUMITOMO BAKELITE Co., Ltd., copper foil 12 μm) having a thickness of 200 μm is used, and a hole is drilled in a predetermined place by a drilling machine, and no electricity is used. The delamination was turned on, and the copper foil was etched to obtain a core layer having a circuit formation surface having a circuit height of 35 μm. Further, the resin sheet A was cut into a single piece, attached to the CVP 300, and temporarily adhered to the core layer, and vacuum-laminated at 120 ° C, 0.7 MPa, and 60 seconds in a vacuum laminator.

(4) Smoothing step

Then, it was smoothed by hot pressing at 120 ° C, 0.6 MPa, and 60 seconds using a hot press apparatus equipped with CPV 300 manufactured by Nichigo Morton Co., Ltd.

(5) Hardening step

Then, heat treatment was performed at 170 ° C for 60 minutes to cure the thermosetting resin of the build-up material to obtain a laminate.

Examples 2 to 7 and Comparative Examples 1 to 4 are in addition to the values of the circuit height, the thickness of the build-up material, the resin varnish composition, the lamination step, and the smoothing step, and are changed to the values shown in Table 1, and the rest are in accordance with the examples. 1 The same method is used to make a laminate.

[assessment]

(1) Determination of complex dynamic viscosity η1 measured by dynamic viscoelasticity test

After completion of the lamination step, a resin composition containing a thermosetting resin was cut out from the build-up layer on the surface of the laminate and used as a measurement sample, and a dynamic viscoelasticity measuring device (manufactured by Anton Paar Co., Ltd., device name Physica MCR-301) was used. The measurement of the complex dynamic viscosity η1 was carried out under the following conditions.

Frequency: 62.83 rad/sec

Measuring temperature: 50~200°C, 3°C/min

Geometry: Parallel Plate

Plate diameter: 10mm

Board spacing: 0.1mm

Load (normal force): ON (certain)

Strain: 0.3%

Measuring environment: air

(2) Determination of complex dynamic viscosity η2 measured by dynamic viscoelasticity test

After the completion of the smoothing step, the resin composition containing the thermosetting resin was cut out from the layer on the surface of the laminate and used as a measurement sample, and the measurement of the complex dynamic viscosity η2 was carried out under the same conditions as the above-described complex dynamic viscosity η1.

(3) Concavity and convexity on the surface of the laminated board

The cross section of the laminate after the hardening step was observed by a scanning electron microscope (SEM), and the difference in thickness between the adjacent copper wiring portion and the copper-free wiring portion was measured.

The thickness difference was measured by n=10, and the average of less than 3.0 μm was rated as qualified and marked as “◎”; the average of 3.0 μm or more and less than 3.5 μm was rated as “○”; the average was 3.5 μm. Those who did not exceed 4.5 μm above were rated as “△” and those with an average of 4.5 μm or more were rated as “X”. The results are shown in Table 1.

The present invention can also take the following aspects.

[1] A method for producing a laminated board, which is carried out continuously on a circuit forming surface of a core layer provided with a circuit forming surface on one or both sides, and laminated with a thermosetting resin under heat and pressure a layered material formed by the resin composition, and a step of laminating the layered body; and a smoothing step of smoothing the surface of the layered layer of the layered layer; and then heating the layered body to make the thermosetting property The resin is further subjected to a hardening hardening step; wherein, in the stage of completion of the laminating step, the build-up material is subjected to a dynamic viscoelastic test according to a measurement range of 50 to 200 ° C, a temperature increase rate of 3 ° C/min, and a frequency of 62.83 rad/sec. When the minimum value of the measured complex dynamic viscosity is η1, η1 is 50 Pa ‧ s or more and 500 Pa ‧ s or less.

[2] The method for producing a laminated board according to the above [1], wherein the build-up material is subjected to a dynamic viscoelasticity test at a stage where the smoothing step is completed, in accordance with a measurement range of 50 to 200 ° C, and a temperature increase rate of 3 When the minimum value of the complex dynamic viscosity obtained at °C/min and the frequency of 62.83 rad/sec is η2, η2≧η1×1.1 is satisfied.

[3] The method for producing a laminated board according to the above [2], wherein the η2 is 520 Pa‧s or more and 10,000 Pa‧s or less.

[4] The method for producing a laminated board according to any one of the above [1], wherein the thickness of the build-up material is 30 μm or less.

[5] The method for producing a laminated board according to any one of the above [1], wherein, in the curing step, the temperature of the layered body is gradually increased from an initial temperature to a maximum temperature.

[6] The method for producing a laminated board according to the above [5], wherein, in the curing step, a temperature increase rate from the initial temperature to the highest reaching temperature is constant.

[7] The method for producing a laminated board according to the above [5], wherein in the curing step, the temperature increase rate from the initial temperature to the highest reaching temperature is at least two or more stages.

[8] The method for producing a laminated board according to any one of the above [5], wherein, in the curing step, an average temperature increase rate from the initial temperature to the highest temperature of arrival is 1 ° C / Above min and below 15 °C / min.

[9] The method for producing a laminated board according to any one of the above [5], wherein, in the curing step, the highest temperature reached is 90 ° C or higher. Below 230 °C.

[10] The method for producing a laminated board according to any one of the above [1], wherein the surface of the layered material is further advanced between the smoothing step and the curing step. Smoothing the second smoothing step.

[11] The method for producing a laminated board according to the above [10], wherein after the smoothing step, the pressure applied to the laminated body is released, and then the second smoothing step is performed.

[12] The method for producing a laminated board according to the above [10], wherein the second smoothing step is performed after the heating temperature is increased to be higher than the smoothing step.

[13] The method for producing a laminated board according to the above [12], wherein the heating temperature difference between the smoothing step and the second smoothing step is 10 ° C or more and 100 ° C or less.

[14] The method for producing a laminated board according to any one of the above [10], wherein, in the second smoothing step, the laminated body is transported while being carried on a belt conveyor Heat and pressurize while performing.

[15] The method for producing a laminated board according to the above [14], wherein the pressurization is performed by mounting a metal member on the laminated body.

[16] The method for producing a laminated board according to the above [15], wherein the metal member has a mass per unit area of 0.01 kg/cm ² or more and 1 kg/cm ² or less.

[17] The method for producing a laminated board according to the above [15], wherein the metal member is made of stainless steel.

[18] The method for producing a laminated board according to any one of the above [10], wherein the second smoothing step is performed twice or more.

[19] The method for producing a laminated board according to any one of the above [1], wherein, in the stacking step, the core layer is interposed between the pair of elastic members and the pair of elastic members. Heating and pressurization are carried out in the state of the layer.

[20] The method for producing a laminated board according to any one of the above [1], wherein the build-up layer is wound in a roll shape; and the build-up material in which the laminate is wound The core layer is conveyed and the sheet-like core layer is conveyed, and the layering step and the smoothing step are continuously performed.

[twenty one] The method for producing a laminated board according to any one of the above aspects, wherein in the smoothing step, the core layer and the build-up material are interposed between a pair of metal members facing each other. Heating and pressurization are performed in the state.

[22] The method for producing a laminated board according to any one of [1] to [21] wherein, after the hardening step, a laser interlayer forming step is further performed.

[23] The method for producing a laminated board according to any one of the above [1], wherein the time of the stacking step in which the total of the vacuuming and the pressurizing time is equal to the time of the smoothing step is equal to .

The present application claims priority on the basis of Japanese Patent Application No. 2011-137598, filed on Jun. 21, 2011, the entire disclosure of which is incorporated herein.

100‧‧‧ laminate

101‧‧‧ Circuitry

102‧‧‧ core layer

103‧‧‧Circuit forming surface

200‧‧‧Additive timber

201‧‧‧ thermosetting resin

300‧‧‧Additional layer

P‧‧‧Resin composition

V‧‧‧resin varnish

Fig. 1 is a cross-sectional view showing a manufacturing step of the laminated plate of the embodiment.

100‧‧‧ laminate

101‧‧‧ Circuitry

102‧‧‧ core layer

103‧‧‧Circuit forming surface

200‧‧‧Additive timber

201‧‧‧ thermosetting resin

300‧‧‧Additional layer

Claims (15)

A method for producing a laminated board is carried out continuously: on the circuit forming surface on which a core layer of a circuit forming surface is provided on one or both sides, and a resin composition containing a thermosetting resin is laminated under heat and pressure a step of laminating the formed layered material to obtain a layered body; and a smoothing step of smoothing the surface of the layered layer of the layered layer; and heating the layered body to further advance the thermosetting resin a hardening hardening step; wherein, in the stage where the laminating step is completed, the multi-layer dynamics is measured by a dynamic viscoelasticity test according to a measurement range of 50 to 200 ° C, a heating rate of 3 ° C/min, and a frequency of 62.83 rad/sec. When the minimum value of the viscosity is η1, η1 is 50 Pa ‧ s or more and 500 Pa ‧ s or less, and at the stage where the smoothing step is completed, the build-up material is subjected to a dynamic viscoelasticity test according to a measurement range of 50 to 200 ° C and a temperature increase rate. When the minimum value of the complex dynamic viscosity obtained at 3 ° C / min and the frequency of 62.83 rad / sec is η 2 , η 2 ≧ η 1 × 1.1 is satisfied. The method for producing a laminate according to the first aspect of the invention, wherein the η2 is 520 Pa‧s or more and 10,000 Pa‧s or less. The method for producing a laminate according to the first or second aspect of the invention, wherein the thickness of the build-up material is 30 μm or less. The method for producing a laminate according to the first or second aspect of the invention, wherein in the hardening step, the temperature of the laminate is caused by an initial temperature Gradually warm up to the highest temperature reached. The method for producing a laminate according to the fourth aspect of the invention, wherein in the curing step, the temperature increase rate from the initial temperature to the highest temperature is at least two or more stages. The method for producing a laminated board according to claim 1 or 2, wherein a second smoothing step of further smoothing the surface of the build-up material is further performed between the smoothing step and the hardening step. The method for producing a laminate according to claim 6, wherein the second smoothing step is performed after the pressure applied to the laminate is released after the smoothing step. The method for producing a laminate according to the sixth aspect of the invention, wherein the second smoothing step is performed by increasing a heating temperature higher than the smoothing step. The method for producing a laminate according to the eighth aspect of the invention, wherein the heating temperature difference between the smoothing step and the second smoothing step is 10° C. or higher and 100° C. or lower. The method for producing a laminate according to the sixth aspect of the invention, wherein the second smoothing step is performed twice or more. The method for producing a laminate according to the first or second aspect of the invention, wherein in the step of laminating, heating is performed in a state in which the core layer and the build-up material are interposed between a pair of elastic members facing each other. Pressurize. A method of manufacturing a laminate according to claim 1 or 2, The layer-added material is wound and laminated in a roll shape, and the layered material is conveyed, and the sheet-like core layer is conveyed, and the layering step and the smoothing step are continuously performed. The method for producing a laminate according to the first or second aspect of the invention, wherein in the smoothing step, heating is performed in a state in which the core layer and the build-up material are interposed between a pair of metal members facing each other. With pressurization. The method for producing a laminate according to the first or second aspect of the invention, wherein the step of forming the laser layer is further performed after the hardening step. The method for producing a laminate according to the first or second aspect of the invention, wherein the time of the stacking step in which the vacuuming and the pressurizing time are combined is equal to the time of the smoothing step.