Laminate manufacturing method

Abstract

To provide a laminate manufacturing method which can suppress a warpage amount.SOLUTION: A laminate manufacturing method includes: a step (A) of preparing a laminate (a) 100 including a substrate 10, and a resin layer 20 for first clad formation; a step (B) of forming a resin layer 30 for core formation on the resin layer 20 for first clad formation, and thereby obtaining a laminate (b) 200 including the substrate 10, the resin layer 20 for first clad formation, and the resin layer 30 for core formation; and a step (C) of heating the laminate (b) 200 at 100°C or lower.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for producing a laminate. [Background technology]

[0002] BACKGROUND ART In recent years, there has been a demand for components in information and communication devices that can realize more advanced information communication, such as larger information capacity and faster information communication speed, and an optoelectronic composite substrate has been considered as one such component.

[0003] An example of an optical / electrical composite substrate is one in which an optical waveguide is provided on a substrate. Techniques relating to the manufacturing method of an optical waveguide include those described in Patent Documents 1 and 2, for example.

[0004] Patent Document 1 describes a method for manufacturing an optical waveguide structure comprising a lower cladding portion, a core portion disposed on the lower cladding portion and propagating light, an upper cladding portion disposed on the core portion, and an optical path conversion portion, a portion of which is disposed within the lower cladding and converts the optical path of light propagating through the core portion, the method comprising: an uncured lower cladding portion forming step for forming an uncured lower cladding portion that will become the lower cladding portion; and an optical path conversion component embedding step for embedding a portion of an optical path conversion component that will become the optical path conversion portion into the uncured lower cladding portion. According to the method for manufacturing an optical waveguide structure in Patent Document 1, it is described that the formation of the core portion is not hindered by the lower cladding portion adhering to the optical path conversion component, and that a highly flexible and accurate design can be easily performed.

[0005] Patent document 2 describes a method for manufacturing an optical waveguide having a core and a clad, which is characterized by comprising a clad-forming resin layer formation step of forming an uncured clad-forming photocurable resin layer, a core-forming resin layer formation step of forming an uncured core-forming photocurable resin layer on the clad-forming resin layer, a light irradiation step of irradiating light only onto the portion of the core-forming resin layer that is to become the core and only onto the portion of the clad-forming resin layer that corresponds to the portion that is to become the core, and a heat treatment step of heat-treating the core-forming resin layer and the clad-forming resin layer. According to the method for manufacturing an optical waveguide in Patent Document 2, it is described that the interlayer adhesion between the cladding layer and the core layer can be increased without plasma treatment. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-331779 [Patent Document 2] Japanese Patent Application Laid-Open No. 2012-98672 Summary of the Invention [Problem to be solved by the invention]

[0007] According to the inventors' investigations, it has been found that the method for manufacturing an optoelectronic composite substrate may result in warping of the resulting optoelectronic composite substrate (hereinafter, in this specification, large warpage of an optoelectronic composite substrate or a laminate is also referred to as a large amount of warpage).

[0008] The present invention provides a method for producing a laminate that can suppress the amount of warpage. [Means for solving the problem]

[0009] According to the present invention, there is provided the following method for producing a laminate.

[0010] [1] A step (A) of preparing a laminate (a) including a substrate and a first clad-forming resin layer; a step (B) of forming a core-forming resin layer on the first clad-forming resin layer to obtain a laminate (b) including the substrate, the first clad-forming resin layer, and the core-forming resin layer; and (C) heat-treating the laminate (b) at 100°C or lower. [2] the method does not include a step of heat-treating the laminate (a) between the step (A) and the step (B), or further includes a step of heat-treating the laminate (a); The method for producing a laminate according to [1] above, wherein the heat treatment temperature in the step of heat treating the laminate (a) is equal to or lower than the heat treatment temperature in the step (C). [3] The method for producing a laminate according to [1] or [2] above, further comprising a step (D) of forming a second clad-forming resin layer on the core-forming resin layer after the step (C), thereby obtaining a laminate (c) comprising the substrate, the first clad-forming resin layer, the core-forming resin layer, and the second clad-forming resin layer. [4] The method for producing a laminate according to [3] above, further comprising a step (E) of heat-treating the laminate (c). [5] The method for producing a laminate according to [4] above, wherein the heat treatment temperature in the step (E) is higher than the heat treatment temperature in the step (C). [6] The method for producing a laminate according to any one of [1] to [5] above, further comprising a step (F) of exposing the laminate (a) to light between the step (A) and the step (B). [7] The method for producing a laminate according to any one of [1] to [6] above, further comprising a step (G) of exposing the laminate (b) to light between the step (B) and the step (C). [8] The method for producing a laminate according to any one of [1] to [7] above, wherein the first clad-forming resin layer contains at least one selected from the group consisting of a resin having a norbornene structure, a polyimide resin, and a compound having a cyclic ether structure. [9] The method for producing a laminate according to any one of the above [1] to [8], wherein the first cladding-forming resin layer contains a photopolymerization initiator.

[10] The method for producing a laminate according to any one of [1] to [9] above, wherein the core-forming resin layer contains at least one selected from the group consisting of a resin having a norbornene structure and a compound having a cyclic ether structure.

[11] The method for producing a laminate according to any one of the above [1] to

[10] , wherein the core-forming resin layer contains a photopolymerization initiator.

[12] The method for producing a laminate according to any one of [1] to

[11] above, wherein the laminate is an optical-electrical composite substrate comprising the substrate, a first clad layer, a core layer, and a second clad layer in this order. [Effects of the Invention]

[0011] According to the present invention, a method for manufacturing a laminate capable of suppressing the amount of warpage can be provided. [Brief explanation of the drawings]

[0012] [Figure 1] 3A to 3C are diagrams illustrating an example of a method for manufacturing a laminate according to the present embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the drawings are simplified and do not correspond to actual dimensional proportions. Numerical ranges "A to B" represent A or more and B or less unless otherwise specified. Furthermore, in this specification, "semi-cured product" refers to a product in a so-called B-stage state, and "cured product" refers to a product in a so-called C-stage state.

[0014] As a method for manufacturing an optical / electrical composite substrate, for example, a method is known in which a first clad-forming resin layer, a core-forming resin layer, and a second clad-forming resin layer are formed in that order on a substrate. According to the investigations of the present inventors, it has been found that the optoelectronic composite substrate obtained by the above method may warp in some cases. The present invention provides a method for producing a laminate that can suppress the amount of warpage.

[0015] [Method of manufacturing laminate] FIG. 1 is a diagram for explaining an example of a method for producing a laminate according to the present embodiment. The method for manufacturing the laminate of this embodiment includes the steps of: (A) preparing a laminate (a) 100 comprising a substrate 10 and a first clad-forming resin layer 20; (B) forming a core-forming resin layer 30 on the first clad-forming resin layer 20 to obtain a laminate (b) 200 comprising the substrate 10, the first clad-forming resin layer 20, and the core-forming resin layer 30; and (C) heat-treating the laminate (b) 200 at 100°C or less.

[0016] Hereinafter, each step of the method for producing a laminate according to this embodiment will be specifically described in the order in which the steps are performed.

[0017] <Process (A)> The method for producing a laminate of this embodiment includes a step (A) of preparing a laminate (a) 100 including a substrate 10 and a first cladding-forming resin layer 20 . FIG. 1(a) is a cross-sectional view that schematically shows an example of the structure of the laminate (a).

[0018] The method for preparing the laminate (a) 100 is not particularly limited, but examples include a method of preparing the laminate (a) 100 by laminating a substrate 10 and a film having a first clad-forming resin layer 20, and a method of preparing the laminate (a) 100 by applying a resin composition for forming the first clad layer onto the substrate 10 and drying it to form the first clad-forming resin layer 20, and preferably a method of preparing the laminate (a) 100 by laminating a substrate 10 and a film having a first clad-forming resin layer 20.

[0019] A method for preparing the laminate (a) 100 by laminating the substrate 10 and the film including the first cladding-forming resin layer 20 will be described. The lamination conditions are, for example, a temperature of 80° C. or more and 180° C. or less, a pressure of 0.1 MPa or more and 10.0 MPa or less, and a time of 10 seconds or more and 250 seconds or less. It is also preferable to vacuum laminate the substrate 10 and the film including the first cladding-forming resin layer 20 using a vacuum laminating machine.

[0020] The substrate 10 is not particularly limited, and examples thereof include a printed circuit board and a flexible substrate, preferably a flexible substrate, and more preferably a flexible double-sided copper-clad laminate. The thickness of the substrate 10 is, for example, 10 μm or more and 1000 μm or less, preferably 20 μm or more and 500 μm or less, and more preferably 30 μm or more and 100 μm or less.

[0021] The first cladding-forming resin layer 20 is not particularly limited as long as it is a layer made of a resin composition that can be used to form a cladding layer of an optical waveguide, but preferred embodiments are as follows.

[0022] The first cladding-forming resin layer 20 preferably contains at least one selected from the group consisting of a resin having a norbornene structure, a polyimide resin, and a compound having a cyclic ether structure. The first cladding-forming resin layer 20 more preferably contains a resin having a norbornene structure and a compound having a cyclic ether structure. In another more preferred embodiment, the first cladding-forming resin layer 20 more preferably contains a polyimide resin and a compound having a cyclic ether structure.

[0023] The resin having a norbornene structure is a resin containing a structural unit derived from a norbornene-based compound, and may contain a structural unit other than the structural unit derived from a norbornene-based compound. Examples of structural units other than those derived from norbornene-based compounds include structural units derived from compounds having an ethylenic double bond and structural units derived from maleimide.

[0024] The polyimide resin is preferably a polyimide resin containing fluorine atoms. The polyimide resin preferably contains an imide ring structure in the molecule.

[0025] The compound having a cyclic ether structure preferably includes at least one selected from the group consisting of epoxy compounds and oxetane compounds.

[0026] The first cladding-forming resin layer 20 preferably contains a photopolymerization initiator, and more preferably contains a photocationic polymerization initiator. The photocationic polymerization initiator includes, for example, at least one selected from the group consisting of sulfonium salt-type polymerization initiators and iodonium salt-type polymerization initiators, and preferably includes a sulfonium salt-type polymerization initiator, more preferably includes a triarylsulfonium salt-type polymerization initiator, and even more preferably includes a triphenylsulfonium salt-type polymerization initiator.

[0027] The thickness of the first cladding-forming resin layer 20 is preferably 1 μm or more and 150 μm or less, more preferably 5 μm or more and 100 μm or less, and even more preferably 10 μm or more and 50 μm or less.

[0028] In step (A), the first cladding-forming resin layer 20 in the laminate (a) 100 is preferably a semi-cured or uncured product, and is preferably a semi-cured product.

[0029] The laminate (a) 100 may have other layers as appropriate, such as a substrate film.

[0030] <Process (F)> The method for producing the laminate of this embodiment preferably further includes a step (F) of exposing the laminate (a) 100 to light between the steps (A) and (B).

[0031] Specifically, the step (F) is a step of exposing the first cladding-forming resin layer 20 in the laminate (a) 100 to light. In step (F), the entire first cladding-forming resin layer 20 may be exposed, or a portion of the first cladding-forming resin layer 20 may be exposed, but it is preferable to expose the entire first cladding-forming resin layer 20.

[0032] In step (F), the integrated light dose is preferably 100 mJ / cm 2 More than 2000mJ / cm 2 Less than or equal to 300 mJ / cm 2 More than 1500mJ / cm 2 or less, more preferably 500 mJ / cm 2 More than 1200mJ / cm 2 The following is the result. In the step (F), the wavelength of the light used for exposure is not particularly limited, and may be adjusted appropriately to match the absorption wavelength of the photopolymerization initiator contained in the first cladding formation resin layer 20 .

[0033] In the step (F), the exposure device is not particularly limited, and examples thereof include a high-pressure mercury lamp and a direct exposure device.

[0034] <Step of Heat-treating the Laminate (a) 100> From the viewpoint of further suppressing the amount of warping of the laminate, the method for manufacturing the laminate of this embodiment preferably does not include a step of heat-treating the laminate (a) 100 between steps (A) and (B), or further includes a step of heat-treating the laminate (a) 100, wherein the heat treatment temperature in the step of heat-treating the laminate (a) 100 is equal to or lower than the heat treatment temperature in step (C).

[0035] According to the investigations of the present inventors, it has been found that performing a step of heat treating the laminate (a) 100 at a high temperature (for example, 160°C) between steps (A) and (B) may cause warping of the laminate (a) 100. The present inventors have also found that warping of the laminate (a) 100 may cause warping of the resulting laminate (for example, an optoelectronic composite substrate). As a result of intensive research, the present inventors have found that the amount of warping of the laminate (a) 100 can be further suppressed by not performing a step of heat-treating the laminate (a) 100 between steps (A) and (B), or by setting the heat treatment temperature in the step of heat-treating the laminate (a) 100 to be equal to or lower than the heat treatment temperature in step (C), thereby further suppressing the amount of warping of the resulting laminate (e.g., an optoelectronic composite substrate).

[0036] When a step of heat treating the laminate (a) 100 is included between step (A) and step (B), the heat treatment temperature is, from the viewpoint of further suppressing the amount of warping of the laminate, preferably 95° C. or less, more preferably 85° C. or less, even more preferably 75° C. or less, even more preferably 65° C. or less, even more preferably 55° C. or less, and even more preferably 45° C. or less, and the lower limit is not particularly limited, but may be, for example, 30° C. or more or 35° C. or more. Furthermore, from the viewpoint of further suppressing the amount of warping of the laminate, the heat treatment temperature is preferably 30° C. or more and 95° C. or less, more preferably 30° C. or more and 85° C. or less, even more preferably 30° C. or more and 75° C. or less, even more preferably 30° C. or more and 65° C. or less, even more preferably 30° C. or more and 55° C. or less, and even more preferably 35° C. or more and 45° C.

[0037] When a step of heat-treating the laminate (a) 100 is included between step (A) and step (B), the heat-treatment time may be, for example, 10 minutes or more and 5 hours or less, or 30 minutes or more and 3 hours or less.

[0038] When a step of heat treating the laminate (a) 100 is included between the step (A) and the step (B), the heating device is not particularly limited, and examples thereof include an atmospheric oven.

[0039] <Process (B)> The method for manufacturing the laminate of this embodiment includes a step (B) of forming a core-forming resin layer 30 on a first clad-forming resin layer 20 to obtain a laminate (b) 200 comprising a substrate 10, a first clad-forming resin layer 20, and a core-forming resin layer 30. FIG. 1(b) is a cross-sectional view that schematically shows an example of the structure of the laminate (b).

[0040] The method for obtaining the laminate (b) 200 is not particularly limited, but examples include a method of laminating the laminate (a) 100 and a film having a core-forming resin layer 30 to obtain the laminate (b) 200, and a method of applying a resin composition for forming a core layer onto the first clad-forming resin layer 20 in the laminate (a) 100 and drying it to form the core-forming resin layer 30 to obtain the laminate (b) 200.Preferred is the method of laminating the laminate (a) 100 and a film having a core-forming resin layer 30 to obtain the laminate (b) 200.

[0041] A method for obtaining the laminate (b) 200 by laminating the laminate (a) 100 and a film having the core-forming resin layer 30 will be described. The lamination conditions are, for example, a temperature of 40° C. or more and 180° C. or less, a pressure of 0.1 MPa or more and 10.0 MPa or less, and a time of 5 seconds or more and 100 seconds or less. It is also preferable to vacuum laminate the laminate (a) 100 and the film provided with the core-forming resin layer 30 using a vacuum laminator.

[0042] The core-forming resin layer 30 is not particularly limited as long as it is a layer made of a resin composition that can be used to form a core layer of an optical waveguide, but preferred embodiments are as follows.

[0043] The core-forming resin layer 30 preferably contains at least one selected from the group consisting of a resin having a norbornene structure and a compound having a cyclic ether structure, and more preferably contains a resin having a norbornene structure and a compound having a cyclic ether structure.

[0044] The core-forming resin layer 30 preferably contains a photopolymerization initiator.

[0045] The resin having a norbornene structure, the compound having a cyclic ether structure, and the photopolymerization initiator contained in the core-forming resin layer 30 may be similar to the resin having a norbornene structure, the compound having a cyclic ether structure, and the photopolymerization initiator contained in the first cladding-forming resin layer 20.

[0046] The thickness of the core-forming resin layer 30 is preferably 1 μm or more and 100 μm or less, more preferably 10 μm or more and 80 μm or less, and even more preferably 20 μm or more and 60 μm or less.

[0047] In step (B), the first cladding-forming resin layer 20 in the laminate (b) 200 is preferably a semi-cured or uncured product, more preferably a semi-cured product. In the step (B), the core-forming resin layer 30 in the laminate (b) 200 is preferably a semi-cured or uncured product, more preferably a semi-cured product.

[0048] The laminate (b) 200 may have other layers as appropriate, such as a base film.

[0049] <Process (G)> The method for producing a laminate of this embodiment preferably further includes a step (G) of exposing the laminate (b) 200 to light between the steps (B) and (C).

[0050] Specifically, the step (G) is a step of exposing the core-forming resin layer 30 in the laminate (b) 200 to light. In the step (G), a part of the core-forming resin layer 30 may be exposed, or the entire core-forming resin layer 30 may be exposed, but preferably a part of the core-forming resin layer 30 is exposed.

[0051] In step (G), the cumulative light amount is not particularly limited, and may be, for example, 40 mJ / cm 2 More than 1000mJ / cm 2 It may be the following: In the step (G), the wavelength of the light used for exposure is not particularly limited, and may be adjusted appropriately to match the absorption wavelength of the photopolymerization initiator contained in the core-forming resin layer 30 .

[0052] In the step (G), the exposure device is not particularly limited, and examples thereof include a direct exposure device and a high-pressure mercury lamp, with a direct exposure device being preferred.

[0053] <Process (C)> The method for producing the laminate of this embodiment includes a step (C) of heat treating the laminate (b) 200 at 100° C. or less.

[0054] According to the study of the present inventors, it has been found that a step of heat treating the laminate (b) 200 at a high temperature (for example, 160°C) may cause warping of the laminate (b) 200. The present inventors have also found that warping of the laminate (b) 200 may cause warping of the optoelectronic composite substrate. As a result of intensive research, the present inventors have found that by setting the temperature during heat treatment of the laminate (b) 200 to a certain temperature or below, the amount of warping of the laminate (b) 200 can be suppressed, and the amount of warping of the resulting laminate (e.g., an optoelectronic composite substrate) can also be suppressed.

[0055] In step (C), the heat treatment temperature is 100° C. or lower, and from the viewpoint of further suppressing the amount of warping of the laminate, it is preferably 90° C. or lower, more preferably 80° C. or lower, even more preferably 70° C. or lower, and even more preferably 65° C. or lower, and the lower limit is not particularly limited, but may be, for example, 30° C. or higher or 35° C. or higher. Furthermore, from the viewpoint of further suppressing the amount of warping of the laminate, the heat treatment temperature is preferably 30° C. or higher and 100° C. or lower, more preferably 30° C. or higher and 90° C. or lower, even more preferably 30° C. or higher and 80° C. or lower, even more preferably 30° C. or higher and 70° C. or lower, and even more preferably 35° C. or higher and 65° C.

[0056] In step (C), the heat treatment time is preferably 10 minutes or more and 5 hours or less, more preferably 30 minutes or more and 3 hours or less.

[0057] After carrying out step (C), the first cladding-forming resin layer 20 in the laminate (b) 200 is preferably a semi-cured or uncured product, more preferably a semi-cured product. After carrying out the step (C), the core-forming resin layer 30 in the laminate (b) 200 is preferably a semi-cured or uncured product, more preferably a semi-cured product. When the method for manufacturing the laminate of this embodiment further includes step (G) of exposing the laminate (b) 200 to light, after step (C) is performed, the exposed portion of the core-forming resin layer 30 in the laminate (b) 200 is preferably semi-cured or uncured, more preferably semi-cured.

[0058] In step (C), the heating device is not particularly limited, and examples thereof include an atmospheric oven.

[0059] <Process (D)> The method for manufacturing the laminate of this embodiment preferably further includes, after step (C), step (D) of forming a second clad-forming resin layer 40 on the core-forming resin layer 30 to obtain a laminate (c) 300 comprising the substrate 10, the first clad-forming resin layer 20, the core-forming resin layer 30, and the second clad-forming resin layer 40. FIG. 1(c) is a cross-sectional view that schematically shows an example of the structure of the laminate (c).

[0060] The method for obtaining the laminate (c) 300 is not particularly limited, but examples thereof include a method of laminating the laminate (b) 200 and a film having a second clad-forming resin layer 40 to obtain the laminate (c) 300, and a method of applying a resin composition for forming the second clad layer onto the core-forming resin layer 30 in the laminate (b) 200 and drying it to form the second clad-forming resin layer 40 to obtain the laminate (c) 300.Preferred is the method of laminating the laminate (b) 200 and a film having the second clad-forming resin layer 40 to obtain the laminate (c) 300.

[0061] A method for obtaining the laminate (c) 300 by laminating the laminate (b) 200 and a film having the second cladding-forming resin layer 40 will be described. The lamination conditions are, for example, a temperature of 80° C. or more and 180° C. or less, a pressure of 0.1 MPa or more and 10.0 MPa or less, and a time of 10 seconds or more and 250 seconds or less. It is also preferable to vacuum laminate the laminate (b) 200 and the film provided with the second cladding-forming resin layer 40 using a vacuum laminator.

[0062] The second cladding-forming resin layer 40 is not particularly limited as long as it is a layer made of a resin composition that can be used to form a cladding layer of an optical waveguide.

[0063] The preferred embodiments of the resin and compound contained in the second cladding-forming resin layer 40 are the same as the preferred embodiments of the resin and compound contained in the first cladding-forming resin layer 20 .

[0064] The second cladding-forming resin layer 40 preferably contains at least one selected from the group consisting of an amine-based compound and a thermal polymerization initiator, more preferably contains at least one selected from the group consisting of an amine-based compound and a thermal cationic polymerization initiator, and even more preferably contains an amine-based compound. The amine compound preferably includes an imidazole compound. The imidazole compound means a compound containing an imidazole ring structure, and includes, for example, a compound in which hydrogen atoms of imidazole are substituted with hydrocarbon groups or the like.

[0065] The thickness of the second cladding forming resin layer 40 is preferably 1 μm or more and 150 μm or less, more preferably 3 μm or more and 100 μm or less, even more preferably 5 μm or more and 50 μm or less, and even more preferably 8 μm or more and 20 μm or less.

[0066] In step (D), the first cladding-forming resin layer 20 in the laminate (c) 300 is preferably a semi-cured or uncured product, more preferably a semi-cured product. In the step (D), the core-forming resin layer 30 in the laminate (c) 300 is preferably a semi-cured or uncured product, more preferably a semi-cured product. When the method for manufacturing the laminate of this embodiment further includes a step (G) of exposing the laminate (b) 200, in step (D), the exposed portion of the core-forming resin layer 30 in the laminate (c) 300 is preferably semi-cured or uncured, more preferably semi-cured. In step (D), the second cladding-forming resin layer 40 in the laminate (c) 300 is preferably a semi-cured or uncured product, more preferably a semi-cured product.

[0067] The laminate (c) 300 may have other layers as appropriate, such as a substrate film, and preferably includes a polyimide substrate.

[0068] <Process (E)> The method for producing the laminate of this embodiment preferably further includes a step (E) of heat treating the laminate (c) 300.

[0069] The heat treatment temperature in step (E) is preferably higher than the heat treatment temperature in step (C). The heat treatment temperature in step (E) is preferably 110°C or higher, more preferably 120°C or higher, even more preferably 130°C or higher, even more preferably 140°C or higher, and even more preferably 150°C or higher, from the viewpoint of further accelerating the curing reaction of each resin layer, and is preferably 250°C or lower, more preferably 220°C or lower, even more preferably 200°C or lower, even more preferably 190°C or lower, and even more preferably 180°C or lower, from the viewpoint of suppressing thermal decomposition of each resin layer. From the viewpoint of further accelerating the curing reaction of each resin layer and suppressing thermal decomposition of each resin layer, the heat treatment temperature is preferably 110°C or higher and 250°C or lower, more preferably 120°C or higher and 220°C or lower, even more preferably 130°C or higher and 200°C or lower, even more preferably 140°C or higher and 190°C or lower, and even more preferably 150°C or higher and 180°C or lower.

[0070] In step (E), the heat treatment time is preferably 10 minutes to 5 hours, more preferably 30 minutes to 3 hours, from the viewpoint of further promoting the curing reaction of each resin layer and further improving production efficiency.

[0071] After carrying out step (E), the first cladding-forming resin layer 20 in the laminate (c) 300 is preferably a cured product. After carrying out the step (E), the core-forming resin layer 30 in the laminate (c) 300 is preferably a cured product. When the method for manufacturing the laminate of this embodiment further includes step (G) of exposing the laminate (b) 200 to light, after step (E) is performed, the exposed portion of the core-forming resin layer 30 in the laminate (c) 300 is preferably a cured product. After carrying out step (E), the second cladding-forming resin layer 40 in the laminate (c) 300 is preferably a cured product.

[0072] In step (E), the heating device is not particularly limited, and examples thereof include an atmospheric oven.

[0073] <Other processes> The method for manufacturing a laminate according to the present embodiment may further include other steps, such as a step of forming a mirror.

[0074] The method for producing the laminate of this embodiment preferably does not include a development treatment step.

[0075] [Laminate] The laminate obtained by the laminate manufacturing method of this embodiment is a laminate including at least a substrate, a first clad-forming resin layer, and a core-forming resin layer in this order. The laminate of this embodiment may further include a base film or the like.

[0076] The laminate of this embodiment is preferably an optical / electrical composite substrate including a substrate, a first clad layer, a core layer, and a second clad layer in this order. The optical / electrical composite substrate of this embodiment preferably includes a substrate, a first clad layer, a core layer, a second clad layer, and a polyimide base material in this order.

[0077] In this specification, the first cladding layer refers to a layer that can be used as the first cladding of an optical waveguide by curing the first cladding-forming resin layer 20. The core layer and the second cladding layer are also defined in the same manner as the first cladding.

[0078] The amount of warpage of the laminate of this embodiment is preferably 50 mm or less, more preferably 40 mm or less, and even more preferably 30 mm or less, and the lower limit is not particularly limited, but may be, for example, 0 mm or more or 3 mm or more. The amount of warpage of the laminate of this embodiment is also preferably 0 mm or more and 50 mm or less, more preferably 0 mm or more and 40 mm or less, and even more preferably 3 mm or more and 30 mm or less. The amount of warpage of the laminate means a value calculated by the following method 1. [Method 1] A laminate measuring 240 mm wide and 320 mm long is used as the sample for evaluating the amount of warpage, and the sample is placed on a horizontal stand with the surface opposite the substrate facing up, and the vertical distance between the apex of the sample for evaluating the amount of warpage and the stand is measured.The vertical distance between the apex of the sample for evaluating the amount of warpage and the stand is measured at each of the four apexes of the sample for evaluating the amount of warpage, and the average value is taken as the amount of warpage.

[0079] Although the embodiments of the present invention have been described above, these are merely examples of the present invention, and various other configurations can also be adopted. Furthermore, the present invention is not limited to the above-described embodiment, and modifications and improvements within the scope of achieving the object of the present invention are included in the present invention. [Example]

[0080] The present embodiment will be described in detail below based on examples and comparative examples, but the present embodiment is not limited to the descriptions of these examples.

[0081] [Raw materials] First, the raw materials used for the films for forming the cladding layer and the core layer will be described.

[0082] <Resin synthesis> (Synthesis of Resin (A-1)) A reaction vessel equipped with a stirrer and a condenser was prepared. The inside of the vessel was first thoroughly purged with nitrogen. Then, 124.8 g (0.7 mol) of n-hexylnorbornene, 54.1 g (0.3 mol) of 2-[(bicyclo[2.2.1]hept-5-en-2-ylmethoxy)methyl]oxirane, and 440 g of toluene were charged and heated to 50 °C in an oil bath while stirring. A solution of 29.9 g (0.02 mol) of (toluene)Ni(CF) dissolved in 5 g of toluene was added and the reaction continued for 3 hours at 50 °C. The resulting solution was reprecipitated in a large amount of methanol to obtain a polymer precipitate, which was then filtered using a suction filter to obtain a polymer powder. The resulting polymer was then dried in vacuum at 60 °C for 16 hours to obtain Resin (A-1) having a norbornene structure. The weight average molecular weight (Mw) of the resin (A-1) having a norbornene structure measured by GPC was 50,000, and the refractive index of the resin (A-1) having a norbornene structure measured by an Abbe refractometer at 23°C and 589 nm was 1.51.

[0083] (Synthesis of Resin (A-2)) A reaction vessel equipped with a stirrer and a condenser was prepared. The inside of the vessel was first thoroughly purged with nitrogen. Then, 124.8 g (0.7 mol) of n-hexylnorbornene, 70.9 g (0.3 mol) of (3-ethyloxetan-3-yl)methyl bicyclo[2.2.1]hept-5-ene-2-carboxylate, and 480 g of toluene were added and heated to 50 °C in an oil bath while stirring. A solution of 29.9 g (0.02 mol) of (toluene)Ni(CF) dissolved in 5 g of toluene was added and the reaction continued for 3 hours at 50 °C. The resulting solution was reprecipitated in a large amount of methanol to obtain a polymer precipitate, which was then filtered using a suction filter to obtain a polymer powder. The resulting polymer was then vacuum dried at 60 °C for 16 hours to obtain a resin (A-2) having a norbornene structure. The weight average molecular weight (Mw) of the resin (A-2) having a norbornene structure measured by GPC was 45,000, and the refractive index of the resin (A-2) having a norbornene structure measured by an Abbe refractometer at 23°C and 589 nm was 1.52.

[0084] (Synthesis of Resin (A-3)) 90.0 g (0.5 mol) of methoxyglycidyl ether norbornene, 24.3 g (0.25 mol) of maleimide, 44.8 g (0.25 mol) of N-cyclohexylmaleimide, and 2.3 g (0.01 mol) of dimethyl 2,2'-azobis(2-methylpropionate) were weighed into an appropriately sized reaction vessel equipped with a stirrer and a condenser, and dissolved in 263 g of methyl ethyl ketone and 113 g of toluene. Dissolved oxygen was then removed from the system by nitrogen bubbling, after which the vessel was sealed and reacted at 70 °C for 16 hours. The resulting solution was cooled to room temperature and reprecipitated in a large amount of heptane to obtain a polymer precipitate. The polymer was then filtered off using a suction filter, and the powder was washed with heptane and dried in a dryer at 60 °C for 24 hours to obtain resin (A-3) having a norbornene structure. The weight average molecular weight (Mw) of the resin (A-3) having a norbornene structure measured by GPC was 8,500, and the refractive index of the resin (A-3) having a norbornene structure measured by an Abbe refractometer at 23°C and 589 nm was 1.51.

[0085] (Synthesis of Resin (A-4)) A 3-liter separable glass flask equipped with a stirrer and a stirring blade was charged with 67.3 g (0.21 mol) of 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl, 97.7 g (0.22 mol) of 4,4'-(hexafluoroisopropylidene)diphthalic dianhydride, and 495 g of dimethylacetamide, and the mixture was stirred to dissolve. The mixture was further stirred at room temperature under a nitrogen stream for 12 hours to carry out the polymerization reaction, yielding a polyamic acid solution.

[0086] After adding 16 g of pyridine to the obtained polyamic acid solution, 82 g of acetic anhydride was added dropwise at room temperature, and then the liquid temperature was kept at 20 to 100°C and stirring was continued for 24 hours to carry out the imidization reaction, thereby obtaining a polyimide solution.

[0087] The resulting polyimide solution was poured into 1,000 g of methanol in a 5 L container while stirring to precipitate a polyimide resin. The solid polyimide resin was then filtered using a suction filter and washed with 1,000 g of methanol. The solid was then dried in a vacuum dryer at 100°C for 24 hours and then at 200°C for 3 hours to obtain polyimide resin (A-4). The weight average molecular weight (Mw) of polyimide resin (A-4) measured by GPC was 51,000, and the refractive index of polyimide resin (A-4) measured by an Abbe refractometer at 23° C. and 589 nm was 1.54.

[0088] (Synthesis of Resin (A-5)) In a glove box filled with dry nitrogen and with moisture and oxygen concentrations both controlled to 1 ppm or less, 7.2 g (40.1 mmol) of n-hexylnorbornene and 12.9 g (40.1 mmol) of diphenylmethylnorbornene methoxysilane were weighed into a 500 mL vial, to which 60 g of dehydrated toluene and 11 g of ethyl acetate were added, and the vial was then sealed with a silicone sealer. Next, 1.56 g (3.2 mmol) of Ni catalyst and 10 mL of dehydrated toluene were weighed into a 100 mL vial, the vial was sealed with a stirrer tip, and the Ni catalyst was thoroughly stirred to completely dissolve, yielding a Ni catalyst solution. 1 mL of the Ni catalyst solution was accurately measured with a syringe and quantitatively injected into the vial containing the two norbornenes dissolved above. Stirring was continued at room temperature for 1 hour, resulting in a significant increase in viscosity. At this point, the stopper was removed, and 60 g of tetrahydrofuran (THF) was added and stirred to obtain a reaction solution. A 100 mL beaker was charged with 9.5 g of acetic anhydride, 18 g of hydrogen peroxide (30% concentration), and 30 g of ion-exchanged water, and the resulting mixture was stirred to prepare an aqueous solution of peracetic acid. The entire amount of the aqueous solution of peracetic acid was then added to the reaction solution and stirred for 12 hours to reduce Ni. Next, the reaction solution was transferred to a separatory funnel, and after removing the lower aqueous layer, 100 mL of a 30% aqueous solution of isopropyl alcohol was added and vigorously stirred. After allowing the mixture to stand and completely separate into two layers, the aqueous layer was removed. This water washing process was repeated a total of three times, and the oil layer was then dropped into a large excess of acetone to reprecipitate the resulting polymer. The filtrate was separated by filtration and then heated and dried for 12 hours in a vacuum dryer set at 60°C to obtain Resin (A-5) having a norbornene structure. The weight-average molecular weight of Resin (A-5) having a norbornene structure measured by GPC was 100,000.

[0089] Details of the raw materials for each component in Table 1 are as follows:

[0090] <Resin (A)> (A-1) Resin synthesized above (A-2) Resin synthesized above (A-3) Resin synthesized above (A-4) Resin synthesized above (A-5) Resin synthesized above

[0091] [ka]

[0092] <Compound (B) Having a Cyclic Ether Structure> (B-1) JER-YX8000 (manufactured by Mitsubishi Chemical Corporation, epoxy compound) (B-2)OXT-221 (manufactured by Toagosei Co., Ltd., oxetane compound) (B-3) Celloxide 2021P (manufactured by Daicel Corporation, epoxy compound) (B-4)OXT-213 (manufactured by Toagosei Co., Ltd., oxetane compound)

[0093] [ka]

[0094] <Curing agent (C)> (C-1) CPI-310B (San-Apro Co., Ltd., photocationic polymerization initiator) (C-2) Curezol C11z (manufactured by Shikoku Chemicals Co., Ltd., imidazole compound)

[0095] <Surfactant (D)> (D-1) BYK-333 (BYK Japan Co., Ltd., silicone surfactant)

[0096] <Organic solvent (E)> (E-1) Toluene (E-2) Propylene glycol monomethyl ether-2-acetate (PGMEA)

[0097] [Creating films for forming cladding and core layers] (Preparation of Resin Composition) The raw materials formulated according to Table 1 were stirred at room temperature until the raw materials were completely dissolved to obtain a solution, which was then filtered through a PTFE filter with a pore size of 0.2 μm to obtain varnish-like resin compositions for clads A to F and core A, respectively.

[0098] (Preparation of film for forming first clad layer) The resin compositions of clads A to D obtained above (preparation of resin compositions) were applied as a varnish using an applicator onto a 38 μm thick antistatic treated polyethylene terephthalate substrate so that the dried thickness would be 25 μm, and then dried at 100°C for 10 minutes.Finally, an OPP cover film was attached to the surface of the resin layer formed by the resin composition to create a film, and films for forming the first clad layers of clads A to D were obtained, respectively.

[0099] (Preparation of film for forming core layer) The resin composition for Core A obtained above (Preparation of Resin Composition) was applied to a release-treated PET film using an applicator so that the film thickness after drying would be 40 μm. After coating, the film was placed in a 45° C. dryer for 5 minutes to completely remove the solvent and form a coating. Finally, an OPP cover film was attached to the surface of the resin layer formed by the resin composition to form a film for forming the core layer of Core A.

[0100] (Preparation of film for forming second clad layer) The resin compositions of Clads E and F obtained above (Preparation of Resin Composition) were applied to a 25 μm thick polyimide substrate using an applicator to a dry thickness of 10 μm, followed by drying at 100°C for 10 minutes. Finally, an OPP cover film was attached to the surface of the resin layer formed by the resin composition to create a film, thereby obtaining films for forming the second clad layers of Clads E and F, respectively.

[0101] [Table 1]

[0102] [Examples 1 to 12 and Comparative Examples 1 to 3] First, in Examples 1 to 12 and Comparative Examples 1 to 3, the films used to form the first clad layer, the core layer, and the second clad layer were the films listed in Table 2.

[0103] <Process (A)> A double-sided copper-clad laminate measuring 240 mm wide, 320 mm long, and 50 μm thick was placed on a stainless steel plate. After peeling off the OPP cover film from the film used to form the first clad layer, the laminate was laminated using a vacuum laminator (Nikko Materials Co., Ltd., CVP-600) at a temperature of 140°C, a pressure of 5.0 MPa, and a time of 120 seconds, so that the first clad-forming resin layer in the film used to form the first clad layer came into contact with the double-sided copper-clad laminate. Laminate A, with a layer structure of "double-sided copper-clad laminate / first clad-forming resin layer / PET substrate," was obtained. The PET substrate here was derived from the film used to form the first clad layer.

[0104] <Process (F)> After step (A), a high-pressure mercury lamp was used to irradiate the entire film with an integrated light dose of 1000 mJ / cm 2 to form the first clad layer in the laminate A. 2 The exposure was carried out under the following conditions.

[0105] After step (F), the laminate A was heat-treated by heating in an atmospheric oven for 1 hour at the temperature shown in Table 2. In Table 2, in the experimental examples marked with "-", no heat treatment was performed.

[0106] <Process (B)> The PET substrate of Laminate A was peeled off, and the OPP cover film of the dry film for forming the core layer was peeled off. The laminate was then laminated using a vacuum laminator (Nikko Materials Co., Ltd., CVP-300) at a temperature of 60°C, a pressure of 0.5 MPa, and a time of 30 seconds, so that the first cladding resin layer in Laminate A came into contact with the core layer in the film for forming the core layer. Laminate B was obtained, with a layer structure of "double-sided copper-clad laminate / first cladding resin layer / core resin layer / PET substrate." Here, the PET substrate was the PET substrate derived from the film for forming the core layer.

[0107] <Process (G)> Next, the core-forming resin layer was exposed to a direct imaging exposure machine (manufactured by SCREEN Co., Ltd., product name: LI-9000) with an integrated light dose of 80 mJ / cm 2 Under the above conditions, 20 lines and spaces with a length of 9 cm, an exposed area of ​​10 μm, and an unexposed area of ​​50 μm were created.

[0108] <Process (C)> Thereafter, the PET substrate derived from the film for forming the core layer was peeled off, and the laminate B was heat-treated by heating in an atmospheric oven for 1 hour at the temperature shown in Table 2. In Comparative Example 3, no heat treatment was performed.

[0109] <Process (D)> Next, the OPP cover film of the film for forming the second cladding layer was peeled off, and the core layer in Laminate B and the second cladding resin layer in the film for forming the second cladding layer were laminated together using a vacuum laminator (Nikko Materials Co., Ltd., CVP-300) at a temperature of 140°C, a pressure of 0.5 MPa, and a time of 120 seconds. Laminate C was obtained, with a layer structure of "double-sided copper-clad laminate / first cladding resin layer / core resin layer / second cladding resin layer / polyimide substrate." The PET substrate here was the polyimide substrate derived from the film for forming the second cladding layer.

[0110] <Process (E)> Laminate C was heated in an atmospheric oven at 160°C for 2 hours to obtain the optoelectronic composite substrates of Examples 1 to 12 and Comparative Examples 1 to 3. The layer structure of the obtained optoelectronic composite substrates was "double-sided copper-clad laminate / first clad layer / core layer / second clad layer / polyimide substrate."

[0111] [evaluation] <Optical loss evaluation> The optoelectronic composite substrates of Examples 1 to 12 and Comparative Examples 1 to 3 were cut by dicing on both sides so that the length of the patterned portion was 7 cm, to obtain samples for evaluating optical loss. The propagation loss of the optical loss evaluation samples was evaluated in accordance with 4.6.2.1 Cutback Method of "Test Methods for Polymer Optical Waveguides (JPCA-PE02-05-01S-2008)." Light with a wavelength of 850 nm was used for the measurements. Based on the results, samples with a propagation loss of less than 1 dB were rated as A, samples with a propagation loss of 1 dB to 3 dB as B, and samples with a propagation loss of more than 3 dB as C.

[0112] <Evaluation of the amount of warpage> The optoelectronic composite substrates (size: width 240 mm, length 320 mm) of Examples 1 to 12 and Comparative Examples 1 to 3 were used as samples for evaluating the amount of warpage. The optoelectronic composite substrate was placed on a horizontal stand with the polyimide substrate side facing up, and the vertical distance between the apex of the sample and the stand was measured. The vertical distance between the stand and each of the four apexes of the sample was measured with a ruler, and the average value was taken as the amount of warpage [mm]. Because the sample for warpage evaluation was rectangular, the four apexes of the sample for warpage evaluation referred to the four corners of the rectangle.

[0113] Table 2 shows the evaluation results for each example and each comparative example.

[0114] [Table 2]

[0115] It can be seen from Table 2 that the optoelectronic composite substrate obtained by the manufacturing method of the example has a smaller amount of warpage than the optoelectronic composite substrate obtained by the manufacturing method of the comparative example. In other words, the manufacturing method of the laminate of this embodiment can suppress the amount of warpage. [Explanation of symbols]

[0116] 10 Substrate 20 First clad-forming resin layer 30 Core forming resin layer 40 Second clad forming resin layer 100 Laminate (a) 200 laminated body (b) 300 laminated body (c)

Claims

1. A step (A) of preparing a laminate (a) including a substrate and a first clad-forming resin layer; a step (B) of forming a core-forming resin layer on the first clad-forming resin layer to obtain a laminate (b) including the substrate, the first clad-forming resin layer, and the core-forming resin layer; and (C) heat-treating the laminate (b) at 100°C or less.

2. The method does not include a step of heat-treating the laminate (a) between the step (A) and the step (B), or further includes a step of heat-treating the laminate (a), The method for producing a laminate according to claim 1 , wherein the heat treatment temperature in the step of heat treating the laminate (a) is equal to or lower than the heat treatment temperature in the step (C).

3. 3. The method for producing a laminate according to claim 1 or 2, further comprising a step (D) of forming a second clad-forming resin layer on the core-forming resin layer after the step (C) to obtain a laminate (c) comprising the substrate, the first clad-forming resin layer, the core-forming resin layer, and the second clad-forming resin layer.

4. The method for producing a laminate according to claim 3 , further comprising a step (E) of heat-treating the laminate (c).

5. The method for producing a laminate according to claim 4 , wherein the heat treatment temperature in the step (E) is higher than the heat treatment temperature in the step (C).

6. The method for producing a laminate according to claim 1 or 2, further comprising a step (F) of exposing the laminate (a) to light between the step (A) and the step (B).

7. The method for producing a laminate according to claim 1 or 2, further comprising a step (G) of exposing the laminate (b) to light between the step (B) and the step (C).

8. 3. The method for producing a laminate according to claim 1, wherein the first clad-forming resin layer contains at least one selected from the group consisting of a resin having a norbornene structure, a polyimide resin, and a compound having a cyclic ether structure.

9. The method for producing a laminate according to claim 1 or 2, wherein the first cladding-forming resin layer contains a photopolymerization initiator.

10. The method for producing a laminate according to claim 1 or 2, wherein the core-forming resin layer contains at least one selected from the group consisting of a resin having a norbornene structure and a compound having a cyclic ether structure.

11. The method for producing a laminate according to claim 1 or 2, wherein the core-forming resin layer contains a photopolymerization initiator.

12. 3. The method for producing a laminate according to claim 1, wherein the laminate is an optical / electrical composite substrate comprising the substrate, a first clad layer, a core layer, and a second clad layer in this order.

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