JP2011029407A - Method of manufacturing wiring board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a wiring board that is superior in suppression of warpage of a substrate, can secure operation efficiency by handling as a substrate which is thick to some extent, and is adaptive even to a copper-clad laminate and also adaptive to a flexible substrate to be rolled. <P>SOLUTION: The method of manufacturing the wiring board includes: sticking two substrates together via an adhesive within a frame-shaped range 0.1 to 50 mm inside outer circumferences of the two substrates into one substrate and forming wirings on both surfaces of the one substrate; and then removing adhesion parts stuck together through the adhesive to separate the one substrate into independent wiring boards. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention is excellent in suppressing warpage of a substrate, can ensure work efficiency as a substrate having a certain thickness, can be applied to a copper-clad laminate, and a flexible substrate can also be applied to roll processing. It is related with the manufacturing method.

Conventionally, in the method of manufacturing a wiring board, for example, in a single-sided wiring board, the wiring density is asymmetric on both sides of the substrate, and in some cases, a large warp may occur during the manufacturing process.
In order to improve this, measures such as providing a reinforcing plate on the back side of the substrate were taken. However, thin flexible substrates with a base material thickness of 25 μm or less had problems such as wrinkles being easily generated when the reinforcing plate was installed. It was.
In addition, extra materials are required for measures such as providing a reinforcing plate on the back side of the substrate, and asymmetry of the substrate is not solved, so the warpage is reduced, but the problem of remaining is not solved and work efficiency deteriorates Was invited.
Further, as described in Patent Document 1, warping can be reduced by using a method of sandwiching two copper foils with a prepreg or a dry film. However, in this method, when a prepreg is used, it cannot be applied to processing of a substrate (polyimide substrate) with a copper foil beforehand such as a flexible substrate or a copper-clad laminate of glass cloth. In addition, when a dry film is laminated and bonded, there is a problem that reliability during the process cannot be ensured, for example, peeling easily occurs during the process.
In addition, as described in Patent Document 2, in the method using the release layer on both sides of the adhesive layer, there are many secondary materials that are discarded after the product is completed, and there are problems of cost and waste disposal, However, the method using the adhesive layer and the release layer decreases the flexibility of the substrate, cannot be rolled, and is difficult to apply to a manufacturing apparatus for a thin substrate.

JP-A-6-209150 JP 2006-49660 A

  The present invention is excellent in suppressing warpage of the substrate, can be handled as a substrate with a certain thickness, can ensure work efficiency, can be applied to copper-clad laminates, and flexible substrates can also handle roll processing An object of the present invention is to provide a method for manufacturing a wiring board.

  As a result of intensive studies, the present inventors bonded two substrates at a part inside the product work to form one substrate, and formed wiring on both surfaces of the one substrate. Later, the present invention was completed by finding that the above object was achieved by separating the adhesive parts by removing them and manufacturing them as independent wiring boards.

That is, the present invention
(1) Two substrates are bonded to each other inside the outer periphery of the two substrates through an adhesive in a frame shape range of 0.1 to 50 mm to form one substrate. Wiring is characterized in that after the wiring is formed on both sides, the one substrate is separated by removing the bonded portion bonded through the adhesive and each is manufactured as an independent wiring board Board manufacturing method,
(2) The method for manufacturing a wiring board according to (1), wherein wiring is further formed on the separation surface after separating the one substrate.
(3) The method for manufacturing a wiring board according to any one of (1) and (2), wherein the wiring includes the optical waveguide and the electric wiring.
(4) The wiring is a single-layer electrical wiring or an electrical wiring that is formed into a multilayer electrical wiring by repeating a step of forming an electrical wiring on the substrate one or more times after laminating a substrate on the electrical wiring surface. A method of manufacturing a wiring board according to any one of (1) and (2),
(5) The method for manufacturing a wiring board according to any one of (1) and (2), wherein the wiring is one or more optical waveguides,
(6) The method for manufacturing a wiring board according to (3) or (4), wherein the electrical wiring is formed using at least one of a subtractive method, an additive method, and a semi-additive method,
(7) The method for manufacturing a wiring board according to (3) or (5), wherein the optical waveguide is an optical waveguide with a mirror,
(8) After forming the wiring on both surfaces of the one substrate, or at least one of the steps after forming the wiring on the separation surface after separating the one substrate, the wiring on the outermost surface The method for manufacturing a wiring board according to any one of (1) to (7), wherein a coating for protecting the wiring is applied.

  According to the manufacturing method of the present invention, it is excellent in suppressing warpage of the substrate, and it is possible to ensure work efficiency by handling as a substrate having a certain thickness by stacking two substrates, and also applicable to copper-clad laminates. Thus, it is possible to manufacture a wiring board that can handle roll processing with a flexible substrate.

It is a figure explaining one embodiment of the manufacturing method of the wiring board of this invention. It is a figure explaining another embodiment of the manufacturing method of the wiring board of this invention.

  As shown in FIG. 1B, for example, the wiring board manufactured according to the present invention is obtained by bonding two substrates 1 with a part inside the product work through an adhesive 3 to form one substrate 2. Then, for example, as shown in FIG. 1E, an optical waveguide 10 in which a lower clad layer 6, a core pattern 7, and an upper clad layer 8 are sequentially laminated on both surfaces of a substrate 2 is joined. . An adhesive 3 may be used for bonding the substrate 2 and the lower cladding layer 6. As another example, as shown in FIG. 2B, electric wirings 5 are formed on both surfaces of the substrate 2.

(Method for bonding two substrates)
The method for bonding the substrates 1 to each other at the frame portion is not particularly limited. However, when bonding with a varnish-like or highly adhesive adhesive 3, the center portion is bonded to the entire surface of the substrate 1. The adhesive 3 may be applied to a place where it is desired to be attached using a plate. In the case of using the above method, it is preferable that the adhesive 3 is first attached to one substrate 1 and then the other substrate 1 is bonded by a vacuum press or a vacuum laminator. In the case where the adhesive 3 is in the form of a sheet having good reworkability, the substrate 1, the adhesive 3 (frame type), and the substrate 1 can be sequentially configured and then bonded together. For the bonding, hand bonding, press, vacuum press, roll laminator, vacuum laminator and the like are preferable, and when there is a heating process in the subsequent process, it is more preferable to use a vacuum press or a vacuum laminator. Moreover, when performing wiring formation with the board | substrate 1 being a roll, it is preferable to use a roll laminator.
In the present invention, the portion where the adhesive 3 is provided needs to be in the range of a frame shape of 0.1 to 50 mm inside the outer periphery of the two substrates 1 and is preferably 1 to 10 mm. If it is less than 0.1, a sufficient adhesive effect cannot be obtained, and if it exceeds 50 mm, there are many parts to be removed, which is disadvantageous in terms of cost.

(Adhesive substrate separation method)
The method for removing the bonded portion bonded through the adhesive is not particularly limited, and the bonded substrate 1 can be separated into two by cutting the bonded portion containing the adhesive by a conventional method. it can.

Hereinafter, each component of the wiring board will be described.
〔substrate〕
Although it does not restrict | limit especially as a kind of board | substrate 1, For example, FR-4 board | substrate, a buildup board | substrate, a polyimide board | substrate, a semiconductor substrate, a silicon substrate, a glass substrate etc. can be used, and those single side | surface or both surfaces A laminated plate in which a metal layer is installed may be used. Further, it may be a flexible flexible material or a non-flexible hard material.
Further, by using a film as the substrate 1, flexibility and toughness can be imparted to the substrate 1 and the optical waveguide 10. The material of the film is not particularly limited, but from the viewpoint of flexibility and toughness, polyesters such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polyethylene, polypropylene, polyamide, polycarbonate, polyphenylene ether, polyether Preferable examples include films of sulfide, polyarylate, liquid crystal polymer, polysulfone, polyethersulfone, polyetheretherketone, polyetherimide, polyamideimide, and polyimide.
The thickness of the film may be appropriately changed depending on the intended flexibility, but is preferably 5 to 250 μm. If it is 5 μm or more, there is an advantage that toughness can be easily obtained, and if it is 250 μm or less, sufficient flexibility can be obtained.

〔adhesive〕
Although it does not specifically limit for the adhesive agent 3, A double-sided tape, a hot-melt-adhesive agent, UV curable adhesive agent, a thermosetting adhesive agent, a prepreg, a buildup material, a heat resistant adhesive agent etc. are mentioned suitably.
Moreover, when it has the process of using a vacuum press or a vacuum lamination, it is preferable that it is a heat resistant adhesive agent, and a prepreg, a buildup material, a heat resistant adhesive agent etc. are mentioned suitably. In the optical waveguide 10, an adhesive having a high transmittance is required for adhesion of a portion through which an optical signal is transmitted. The material of the adhesive 3 is not particularly limited, but the adhesion described in (PCT / JP2008 / 05465). More preferably, an agent is used. The thickness of the adhesive may be in a range that does not affect the process after bonding, and is more preferably 25 μm or less.
Moreover, when performing wiring formation with the board | substrate 1 being a roll, it is preferable to use the adhesive agent which has sufficient softness | flexibility after hardening. When the wiring is formed using the substrate 1 as a tough substrate, it is preferable to use an adhesive having sufficient rigidity after curing.

〔wiring〕
The wiring refers to an electric wiring 5 patterned with a conductor such as a metal layer, an optical wiring such as an optical waveguide 10, each multilayer board, and a multilayer board in which each is combined.
Specifically, (i) a wiring composed of an optical waveguide and electrical wiring, (ii) a single layer of electrical wiring, or a process of forming an electrical wiring on the substrate after laminating a substrate on the surface on which the electrical wiring is formed There are multilayer electrical wirings in which the above is repeated once or more, and (iii) wirings that are one or more optical waveguides.

[Method of forming electrical wiring]
As a method for forming the electric wiring 5, a metal layer is formed on the surface on which the electric wiring 5 is formed, an etching resist is further formed, and unnecessary portions of the metal layer are removed by etching (subtract method), and a plating resist is formed. A method of forming the electric wiring 5 by plating only on a necessary portion of the surface on which the electric wiring 5 is to be formed (additive method), forming a thin metal layer (seed layer) on the surface on which the electric wiring 5 is to be formed, There is a method (semi-additive method) in which a plating resist is formed, and then an electric wiring 5 necessary for electroplating is formed, and then a thin metal layer is removed by etching.
Any method may be used as the method for forming the electrical wiring 5, but the semi-additive method is more preferable in order to form fine wiring with (electric wiring width) ≦ 20 μm.
The etching resist or plating resist used for forming the electric wiring can be either a positive type or a negative type. However, the positive type resist is more preferable because fine wiring can be easily formed.

[Formation of seed layer in semi-additive process]
In the case of forming the electric wiring by the semi-additive method, there are a method for forming the seed layer on the surface on which the electric wiring 5 is formed, a method by vapor deposition or plating, and a method of bonding a metal layer.

[Formation of seed layer by vapor deposition or plating]
A seed layer can be formed on the surface on which the electrical wiring 5 is to be formed by vapor deposition or plating.
For example, when a base metal and a thin film copper layer are formed by sputtering as a seed layer, the sputtering apparatus used to form the thin film copper layer is a bipolar sputtering, a three-pole sputtering, a four-pole sputtering, a magnetron sputtering, a mirror. Tron sputtering or the like can be used.
A target used for sputtering is sputtered 5 to 50 nm using, for example, a metal such as Cr, Ni, Co, Pd, Zr, Ni / Cr, or Ni / Cu as a base metal in order to ensure adhesion.
Thereafter, a seed layer can be formed by sputtering 200 to 500 nm using copper as a target.
Moreover, it is also possible to form plated copper on the surface on which the electric wiring 5 is formed by performing electroless copper plating of 0.5 to 3 μm.

[Method of bonding metal layers]
If the surface on which the electric wiring 5 is formed has adhesive performance, the seed layer can also be formed by bonding the metal layer by pressing or laminating.
However, since it is very difficult to directly bond a thin metal layer, there are a method of thinning a thick metal layer after etching, a method of thinning by etching, a method of removing a carrier layer after bonding a metal layer with a carrier, etc. is there.
For example, the former has a three-layer copper foil of carrier copper / nickel / thin film copper, the carrier copper is removed with an alkali etching solution, nickel is removed with a nickel etching solution, and the latter is made of aluminum, copper, insulating resin, etc. The peelable copper foil can be used, and a seed layer of 5 μm or less can be formed.
Alternatively, a metal layer (for example, a metal foil such as a copper foil) having a thickness of 9 to 18 μm may be attached, and the seed layer may be formed by etching to a thickness of 5 μm or less.
Although what is generally used should just be used about the kind of electroplating, in order to form the electrical wiring 5, it is preferable to use copper as a plating metal.

[Electric wiring formation by additive method]
In the case of forming the electrical wiring by the additive method, as in the semi-additive method, it is formed by plating only on a necessary portion of the surface on which the electrical wiring 5 is formed. However, the plating used in the additive method is usually not used. Electroplating is used.
For example, after depositing an electroless plating catalyst on the surface on which the electric wiring 5 is to be formed, a plating resist is formed on the surface portion where plating is not performed, and the substrate is immersed in an electroless plating solution and covered with the plating resist. Electroless plating is performed only at the locations where there is no electrical wiring 5.

[Formation of coating for wiring protection]
An insulating coating can be formed on the outermost surface (wiring surface located in the outermost layer) of the wiring board obtained as the final product. In the case of electrical wiring, the pattern formation of the insulation coating can be performed by printing if it is a varnish-like material, but in order to ensure more accuracy, a photosensitive solder resist, a coverlay film, It is preferable to use a film resist. Moreover, when there is an optical waveguide with a mirror in the product (in the case of an optical wiring), it is preferable to protect the mirror portion using a protective film with an adhesive.
As a material, an epoxy-based material, a polyimide-based material, an epoxy acrylate-based material, or a fluorene-based material can be used.

[Method of forming optical waveguide]
Hereinafter, the manufacturing method of the wiring board of this invention which formed the optical waveguide on both surfaces of the board | substrate 2 is explained in full detail (refer FIG. 1).
First, as shown in FIG. 1C, the lower clad layer 6 is provided on both surfaces of the substrate 2, and the core pattern 7 is formed thereon. Further, an upper cladding layer 8 is laminated to form a mirror part (see FIG. 1D). When there is no adhesive force between the substrate 2 and the lower clad layer 6, they may be attached via the adhesive layer 3. Further, a method of directly sticking the optical waveguide substrate having the lower clad layer 6, the core pattern 7, and the upper clad layer 8 as described above onto the electric wiring 5 through the adhesive 3 can be used.
The formation of the lower clad layer 6 on the substrate 2 is not particularly limited and may be performed by a known method. For example, a material for forming the lower clad layer 6 is applied on the lower support film by spin coating or the like, and prebaked. Thereafter, the thin film can be formed by irradiating ultraviolet rays. Also, the formation of the core pattern 7 is not particularly limited. For example, a core layer having a refractive index higher than that of the lower cladding layer 6 may be formed on the lower cladding layer 6 and the core pattern 7 may be formed by etching. The formation method of the upper cladding layer 8 is not particularly limited, and may be formed by, for example, the same method as that for the lower cladding layer 6.

[Lower cladding layer and upper cladding layer]
Hereinafter, the lower clad layer 6 and the upper clad layer 8 used in the present invention will be described. As the lower clad layer 6 and the upper clad layer 8, a clad layer forming resin or a clad layer forming resin film can be used.

  The clad layer forming resin used in the present invention is not particularly limited as long as it is a resin composition that has a lower refractive index than the core layer and is cured by light or heat, and includes a thermosetting resin composition and a photosensitive resin composition. It can be preferably used. More preferably, the clad layer forming resin is preferably composed of a resin composition containing (A) a base polymer, (B) a photopolymerizable compound, and (C) a photopolymerization initiator. The resin composition used for the clad layer forming resin may be the same or different in the components contained in the resin composition in the upper clad layer 8 and the lower clad layer 6. The refractive indexes may be the same or different.

  The (A) base polymer used here is for forming a clad layer and ensuring the strength of the clad layer, and is not particularly limited as long as the object can be achieved, phenoxy resin, epoxy resin, (Meth) acrylic resin, polycarbonate resin, polyarylate resin, polyether amide, polyether imide, polyether sulfone, etc., or derivatives thereof. These base polymers may be used alone or in combination of two or more. Of the base polymers exemplified above, from the viewpoint of high heat resistance, the main chain preferably has an aromatic skeleton, and particularly preferably a phenoxy resin. From the viewpoint of three-dimensional crosslinking and improving heat resistance, an epoxy resin, particularly an epoxy resin that is solid at room temperature is preferable. Further, compatibility with the photopolymerizable compound (B) described in detail later is important for ensuring the transparency of the resin for forming the cladding layer. From this point, the phenoxy resin and the (meth) acrylic resin are used. Is preferred. Here, (meth) acrylic resin means acrylic resin and methacrylic resin.

  Among phenoxy resins, phenoxy resin using at least one selected from bisphenol A, bisphenol A type epoxy compound bisphenol F, bisphenol F type epoxy compound and derivatives thereof as a copolymerization component has excellent heat resistance, adhesion and solubility. It is preferable because it is excellent. Preferred examples of the bisphenol A or bisphenol A type epoxy compound include tetrabromobisphenol A and tetrabromobisphenol A type epoxy compounds. Moreover, as a derivative of bisphenol F or a bisphenol F-type epoxy compound, tetrabromobisphenol F, a tetrabromobisphenol F-type epoxy compound, etc. are mentioned suitably. Specific examples of the bisphenol A / bisphenol F copolymer type phenoxy resin include “Phenotote YP-70” (trade name) manufactured by Toto Kasei Co., Ltd.

  As the bisphenol A type epoxy resin, as an epoxy resin solid at room temperature, for example, “Epototo YD-7020, Epototo YD-7919, Epototo YD-7007” (all trade names) manufactured by Toto Chemical Co., Ltd., Japan Epoxy Resin Co., Ltd. "Epicoat 1010, Epicoat 1009, Epicoat 1008" (all are brand names) etc. are mentioned.

Next, (B) the photopolymerizable compound is not particularly limited as long as it is polymerized by irradiation with light such as ultraviolet rays, and the compound having an ethylenically unsaturated group in the molecule or two or more in the molecule. Examples thereof include compounds having an epoxy group.
Examples of the compound having an ethylenically unsaturated group in the molecule include (meth) acrylate, vinylidene halide, vinyl ether, vinyl pyridine, vinyl phenol, etc., among these, from the viewpoint of transparency and heat resistance, (Meth) acrylate is preferred.
As the (meth) acrylate, any of monofunctional, bifunctional, trifunctional or higher polyfunctional ones can be used. Here, (meth) acrylate indicates acrylate and methacrylate. An acrylate means a compound having an acryloyl group, and a methacrylate means a compound having a methacryloyl group. Moreover, monofunctional here means having any one of an acryloyl group and a methacryloyl group.
Examples of the compound having two or more epoxy groups in the molecule include bifunctional or polyfunctional aromatic glycidyl ethers such as bisphenol A type epoxy resins, bifunctional or polyfunctional aliphatic glycidyl ethers such as polyethylene glycol type epoxy resins, and water. Bifunctional alicyclic glycidyl ether such as bisphenol A type epoxy resin, bifunctional aromatic glycidyl ester such as diglycidyl phthalate, bifunctional alicyclic glycidyl ester such as tetrahydrophthalic acid diglycidyl ester, N, N- Bifunctional or polyfunctional aromatic glycidylamine such as diglycidylaniline, bifunctional alicyclic epoxy resin such as alicyclic diepoxycarboxylate, bifunctional heterocyclic epoxy resin, polyfunctional heterocyclic epoxy resin, bifunctional Or polyfunctional silicon-containing epoxy resin It is. These (B) photopolymerizable compounds can be used alone or in combination of two or more.

  Next, the photopolymerization initiator of component (C) is not particularly limited. For example, as an initiator when an epoxy compound is used as component (B), aryldiazonium salt, diaryliodonium salt, triarylsulfonium salt, triallyl Examples include selenonium salts, dialkylphenazylsulfonium salts, dialkyl-4-hydroxyphenylsulfonium salts, and sulfonate esters.

Moreover, as an initiator in the case of using a compound having an ethylenically unsaturated group in the molecule as the component (B), aromatic ketones such as benzophenone, quinones such as 2-ethylanthraquinone, benzoin ethers such as benzoin methyl ether Compounds, benzoin compounds such as benzoin, benzyl derivatives such as benzyldimethyl ketal, 2,4,5-triarylimidazole dimers such as 2- (o-chlorophenyl) -4,5-diphenylimidazole dimer, 2- Benzimidazoles such as mercaptobenzimidazole, phosphine oxides such as bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide, acridine derivatives such as 9-phenylacridine, N-phenylglycine, N-phenylglycine derivatives , Coumarin compound And the like. Moreover, you may combine a thioxanthone type compound and a tertiary amine compound like the combination of diethyl thioxanthone and dimethylaminobenzoic acid. Of these compounds, aromatic ketones and phosphine oxides are preferred from the viewpoint of improving the transparency of the core layer and the cladding layer.
These (C) photopolymerization initiators can be used alone or in combination of two or more.

(A) It is preferable that the compounding quantity of a base polymer shall be 5-80 mass% with respect to the total amount of (A) component and (B) component. Moreover, it is preferable that the compounding quantity of (B) photopolymerizable compound shall be 95-20 mass% with respect to the total amount of (A) and (B) component.
As a blending amount of the component (A) and the component (B), when the component (A) is 5% by mass or more and the component (B) is 95% by mass or less, the resin composition is easily formed into a film. Can do. On the other hand, when the (A) component is 80% by mass or less and the (B) component is 20% by mass or more, the (A) base polymer can be easily entangled and cured, and an optical waveguide is formed. The pattern forming property is improved and the photocuring reaction proceeds sufficiently. From the above viewpoint, the blending amount of the component (A) and the component (B) is more preferably 10 to 85% by mass of the component (A) and 90 to 15% by mass of the component (B), and the component 20 to 70. More preferably, the content is 80% by mass and the component (B) is 80 to 30% by mass.
(C) It is preferable that the compounding quantity of a photoinitiator shall be 0.1-10 mass parts with respect to 100 mass parts of total amounts of (A) component and (B) component. When the blending amount is 0.1 parts by mass or more, the photosensitivity is sufficient, while when it is 10 parts by mass or less, the absorption in the surface layer of the photosensitive resin composition does not increase during exposure, and the internal Is sufficiently cured. Furthermore, when used as an optical waveguide, it is preferable that the propagation loss does not increase due to the light absorption effect of the polymerization initiator itself. From the above viewpoint, the blending amount of (C) the photopolymerization initiator is more preferably 0.2 to 5 parts by mass.
In addition, if necessary, in the cladding layer forming resin, an antioxidant, an anti-yellowing agent, an ultraviolet absorber, a visible light absorber, a colorant, a plasticizer, a stabilizer, a filler, etc. You may add what is called an additive in the ratio which does not have a bad influence on the effect of this invention.

In the present invention, the method for forming the clad layer is not particularly limited. For example, the clad layer may be formed by applying a clad layer forming resin or laminating a clad layer forming resin film.
In the case of application, the method is not limited. For example, the resin composition containing the components (A) to (C) may be applied by a conventional method.
Moreover, the resin film for clad layer formation used for a lamination can be easily manufactured, for example by melt | dissolving the said resin composition in a solvent, apply | coating to a support film, and removing a solvent.

The material of the support film used in the production process of the resin film for forming a clad layer is not particularly limited, and various types can be used. From the viewpoints of flexibility and toughness as a support film, those exemplified above as the film material of the substrate can be similarly mentioned.
The thickness of the support film may be appropriately changed depending on the intended flexibility, but is preferably 5 to 250 μm. If it is 5 μm or more, there is an advantage that toughness can be easily obtained, and if it is 250 μm or less, sufficient flexibility can be obtained.
The solvent used here is not particularly limited as long as it can dissolve the resin composition. For example, acetone, methyl ethyl ketone, methyl cellosolve, ethyl cellosolve, toluene, N, N-dimethylacetamide, propylene glycol monomethyl ether, propylene A solvent such as glycol monomethyl ether acetate, cyclohexanone, N-methyl-2-pyrrolidone, or a mixed solvent thereof can be used. The solid content concentration in the resin solution is preferably about 30 to 80% by mass.

  Regarding the thickness of the lower clad layer 6 and the upper clad layer 8 (hereinafter abbreviated as clad layers 6 and 8), the thickness after drying is preferably in the range of 5 to 500 μm. When the thickness is 5 μm or more, a clad thickness necessary for light confinement can be secured, and when the thickness is 500 μm or less, it is easy to control the film thickness uniformly. From the above viewpoint, the thickness of the cladding layers 6 and 8 is more preferably in the range of 10 to 100 μm.

  The thicknesses of the clad layers 6 and 8 may be the same or different in the lower clad layer 6 formed first and the upper clad layer 8 for embedding the core pattern 7. For embedding, it is preferable that the thickness of the upper cladding layer 8 is larger than the thickness of the core layer.

[Core layer forming resin and core layer forming resin film]
In the present invention, the method for forming the core layer laminated on the lower clad layer 6 in order to form the core pattern 7 is not particularly limited. For example, the coating of the core layer forming resin or the lamination of the core layer forming resin film is performed. It may be formed by.
As the resin for forming the core layer, a resin composition that is designed so that the core pattern 7 has a higher refractive index than the cladding layers 6 and 8 and can form the core pattern 7 with actinic rays can be used. Compositions are preferred. Specifically, it is preferable to use the same resin composition as that used in the clad layer forming resin.
In the case of application, the method is not limited, and the resin composition may be applied by a conventional method.

Hereinafter, the resin film for core layer formation used for lamination is explained in full detail.
The resin film for forming a core layer can be easily produced by dissolving the resin composition in a solvent and applying the resin composition to the lower cladding layer 6 and removing the solvent. The solvent used here is not particularly limited as long as it can dissolve the resin composition. For example, acetone, methyl ethyl ketone, methyl cellosolve, ethyl cellosolve, toluene, N, N-dimethylformamide, N, N-dimethyl A solvent such as acetamide, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, cyclohexanone, N-methyl-2-pyrrolidone, or a mixed solvent thereof can be used. It is preferable that the solid content concentration in the resin solution is usually 30 to 80% by mass.

  The thickness of the resin film for forming the core layer is not particularly limited, and the thickness of the core layer after drying is usually adjusted to be 10 to 100 μm. When the thickness of the film is 10 μm or more, there is an advantage that the alignment tolerance can be increased in the coupling with the light emitting / receiving element or the optical fiber after the optical waveguide is formed, and when the thickness is 100 μm or less, the light receiving / emitting after the optical waveguide is formed. In coupling with an element or an optical fiber, there is an advantage that coupling efficiency is improved. From the above viewpoint, the thickness of the film is preferably in the range of 30 to 70 μm.

The support film used in the manufacturing process of the core layer forming resin is a support film that supports the core layer forming resin, and the material thereof is not particularly limited, but it is easy to peel off the core layer forming resin later. From the viewpoint of having heat resistance and solvent resistance, polyesters such as polyethylene terephthalate, polypropylene, polyethylene, and the like are preferable.
The thickness of the support film is preferably 5 to 50 μm. When it is 5 μm or more, there is an advantage that the strength as a support film is easily obtained, and when it is 50 μm or less, there is an advantage that a gap with the mask at the time of pattern formation becomes small and a finer pattern can be formed. From the above viewpoint, the thickness of the support film is more preferably in the range of 10 to 40 μm, and particularly preferably 15 to 30 μm.

  The optical waveguide 10 used in the present invention may be a multilayer optical waveguide in which a plurality of polymer layers having a core pattern and a cladding layer are stacked.

  EXAMPLES The present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples.

[Preparation of adhesive]
An adhesive described in PCT / JP2008 / 05465 was prepared. That is, (a) YDCN-703 (trade name, manufactured by Toto Kasei Co., Ltd., cresol novolac type epoxy resin, epoxy equivalent 210) 55 parts by mass as an epoxy resin, (b) Millex XLC-LL (Mitsui Chemicals, Inc.) as a curing agent Product name, phenol resin, hydroxyl group equivalent 175, water absorption rate 1.8% by mass, heating weight reduction rate 4% at 350 ° C. 45% by mass, silane coupling agent NUC A-189 (trade name, manufactured by Nihon Unicar Co., Ltd.) 1.7 parts by weight of γ-mercaptopropyltrimethoxysilane) and 3.2 parts by weight of NUC A-1160 (trade name, γ-ureidopropyltriethoxysilane manufactured by Nihon Unicar Co., Ltd.), (d) Aerosil R972 (silica) as filler The surface is coated with dimethyldichlorosilane and hydrolyzed in a 400 ° C reactor. , A filler having an organic group such as a methyl group on its surface, Nippon Aerosil Co., Ltd., trade name, silica, average particle size 0.016 μm) 32 parts by mass, cyclohexanone is added to the mixture, and the mixture is further stirred. And kneaded for 90 minutes. 280 parts by mass of (c) acrylic rubber HTR-860P-3 (trade name, weight average molecular weight of 800,000 manufactured by Nagase ChemteX Corporation) containing 3% by mass of glycidyl acrylate or glycidyl methacrylate as a polymer compound, and (e ) Curazole 2PZ-CN (trade name, 1-cyanoethyl-2-phenylimidazole manufactured by Shikoku Kasei Kogyo Co., Ltd.) as a curing accelerator was added in an amount of 0.5 parts by mass, stirred and mixed, and vacuum degassed. This adhesive varnish was applied onto a 75 μm thick polyethylene terephthalate (PET) film (Purex A31) subjected to a release treatment, dried by heating at 140 ° C. for 5 minutes, and then a 25 μm release mold as a second protective film. The treated polyethylene terephthalate (PET) film (Purex A31) was attached so that the release surface was on the resin side, and an adhesive was obtained.
Hereinafter, the description will be made on the assumption that the adhesive is in a state immediately after the second protective film is peeled off immediately before use.

Example 1
(1) Bonding of substrates Polyimide with single-sided copper foil Product name: Upicel N, manufactured by Ube Nitto Kasei Kogyo Co., Ltd., copper foil thickness: 5 μm, polyimide thickness 12.5 μm) product size (150 mm square) A release sheet (trade name: Aflex, manufactured by Asahi Glass Co., Ltd., thickness: 30 μm) smaller than each side by 10 mm is installed, and the adhesive 3 obtained by producing the adhesive from above is formed into a flat plate type. A vacuum pressurization type laminator (MVLP-500, manufactured by Meiki Seisakusho Co., Ltd.) was used as a laminator. After vacuuming to 500 Pa or less, thermocompression bonding was performed under conditions of a pressure of 0.4 MPa, a temperature of 50 ° C., and a pressurization time of 30 seconds. .
Thereafter, the adhesive 3 is irradiated with 1 J / cm ² of ultraviolet light (wavelength 365 nm) with an ultraviolet exposure machine (EXM-1172, manufactured by Oak Manufacturing Co., Ltd.), and a release PET film (Purex) which is a protective film of the adhesive 3 A31) was peeled off, and the adhesive 3 adhered to the release sheet was peeled off together with the release sheet to obtain a substrate 1 with the adhesive 3 only on the frame portion (see FIG. 1A).
Next, on the bonding surface of the substrate 1 obtained above, the copper foil surface of the polyimide with a single-sided copper foil (150 mm square) is subjected to thermocompression bonding under the above conditions using the above-described vacuum pressure laminator. And the board | substrate 2 with which the board | substrate 1 was affixed by the product frame part was obtained by heat-hardening at 180 degreeC for 1 hour (refer FIG.1 (b)).

(2) Production of optical waveguide [production of resin film for forming clad layer]
(A) As a base polymer, 48 parts by mass of phenoxy resin (trade name: Phenototo YP-70, manufactured by Toto Kasei Co., Ltd.), (B) As a photopolymerizable compound, alicyclic diepoxycarboxylate (trade name: KRM) -2110, molecular weight: 252, Asahi Denka Kogyo Co., Ltd.) 50 parts by mass, (C) As a photopolymerization initiator, triphenylsulfonium hexafluoroantimonate salt (trade name: SP-170, Asahi Denka Kogyo Co., Ltd.) 2 parts by mass, 40 parts by mass of propylene glycol monomethyl ether acetate as an organic solvent are weighed in a wide-mouthed plastic bottle, and stirred for 6 hours under the conditions of a temperature of 25 ° C. and a rotation speed of 400 rpm using a mechanical stirrer, shaft and propeller. A clad layer forming resin varnish A was prepared. After that, using a polyflon filter (trade name: PF020, manufactured by Advantech Toyo Co., Ltd.) with a pore diameter of 2 μm, the mixture is filtered under pressure at a temperature of 25 ° C. and a pressure of 0.4 MPa, and further the degree of vacuum using a vacuum pump and a bell jar. Degassed under reduced pressure for 15 minutes under the condition of 50 mmHg.
The clad layer forming resin varnish A obtained above is applied to a release PET film (trade name: PUREX A31, Teijin DuPont Films Co., Ltd., thickness: 25 μm) as a coating machine (Multicoater TM-MC, Co., Ltd.). It is applied using Hirano Tech Seed, dried at 80 ° C. for 10 minutes, then at 100 ° C. for 10 minutes, and then as a protective film, a release PET film (trade name: Purex A31, Teijin DuPont Films Co., Ltd., thickness: 25 μm) ) Was attached so that the release surface was on the resin side to obtain a resin film for forming a cladding layer. At this time, the thickness of the resin layer can be arbitrarily adjusted by adjusting the gap of the coating machine. In this embodiment, the cured film thickness is 25 μm for the lower cladding layer and 70 μm for the upper cladding layer. Adjusted.

[Production of resin film for core layer formation]
(A) As a base polymer, 26 parts by mass of phenoxy resin (trade name: Phenototo YP-70, manufactured by Toto Kasei Co., Ltd.), (B) 9,9-bis [4- (2-acryloyl) as a photopolymerizable compound Oxyethoxy) phenyl] fluorene (trade name: A-BPEF, Shin-Nakamura Chemical Co., Ltd.) 36 parts by mass, and bisphenol A type epoxy acrylate (trade name: EA-1020, Shin-Nakamura Chemical Co., Ltd.) 36 mass Parts, (C) 1 part by mass of bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide (trade name: Irgacure 819, manufactured by Ciba Specialty Chemicals) as a photopolymerization initiator, and 1- [4 -(2-Hydroxyethoxy) phenyl] -2-hydroxy-2-methyl-1-propan-1-one (trade name: yl Cure 2959, manufactured by Ciba Specialty Chemicals) 1 part by weight, and using resin varnish B for forming a core layer under the same method and conditions as in the above production example, except that 40 parts by weight of propylene glycol monomethyl ether acetate was used as the organic solvent Prepared. Thereafter, pressure filtration and degassing under reduced pressure were performed under the same method and conditions as in the above production example.
The core layer-forming resin varnish B obtained above is applied to the non-treated surface of a PET film (trade name: Cosmo Shine A1517, manufactured by Toyobo Co., Ltd., thickness: 16 μm) in the same manner as in the above production example. After coating and drying, a release PET film (trade name: PUREX A31, Teijin DuPont Films Co., Ltd., thickness: 25 μm) is applied as a protective film so that the release surface is on the resin side, and a core layer forming resin A film was obtained. In this example, the gap of the coating machine was adjusted so that the film thickness after curing was 50 μm.

(3) Production of Photoelectric Composite Member (Wiring Board Combined with Optical Waveguide) A method for producing an optoelectric composite member will be described below with reference to FIGS.
A pressure laminator (HLM-1500, manufactured by Hitachi Chemical Technoplant Co., Ltd.) is used on both surfaces of the substrate 2 obtained as described above, and a laminate of the adhesive 3 described above is laminated using a roll laminator (HLM-1500, manufactured by Hitachi Chemical Technoplant Co., Ltd.). Lamination was performed at a speed of 0.2 m / min.
Thereafter, the adhesive 3 was irradiated with 1 J / cm ² of ultraviolet light (wavelength 365 nm) with an ultraviolet exposure machine (EXM-1172, manufactured by Oak Manufacturing Co., Ltd.), and release PET as a protective film of the adhesive 3 described above. The film (Purex A31) was peeled off.
Next, the release PET film (Purex A31), which is a protective film for the resin film for forming the lower cladding layer obtained above, is peeled off, and the same laminate as above is laminated on the adhesive surface of the substrate 2 obtained above. By pasting under conditions, UV irradiation (wavelength 365 nm) 1.5 J / cm ² from the resin side with an ultraviolet exposure machine (manufactured by Oak Manufacturing Co., Ltd., EXM-1172), followed by heat treatment at 80 ° C. for 10 minutes The lower clad layer 6 was formed.
Next, the core layer forming resin film was laminated on the lower clad layer 6 under the same lamination conditions as above to form a core layer.

Next, ultraviolet rays (wavelength 365 nm) were irradiated with 0.8 J / cm ² with a UV photomask through a negative photomask having a width of 50 μm, and then after exposure at 80 ° C. for 5 minutes, heating was performed. Thereafter, the PET film as the support film was peeled off, and the core pattern 7 was developed using a developer (propylene glycol monomethyl ether acetate / N, N-dimethylacetamide = 7/3, mass ratio). Then, it wash | cleaned using the washing | cleaning liquid (isopropanol), and heat-dried at 100 degreeC for 10 minute (s). (See Fig. 1 (c))

Next, a vacuum pressure laminator (MVLP-500, manufactured by Meiki Seisakusho Co., Ltd.) is used as the flat plate laminator, and the resin film for forming the clad layer is evacuated to 500 Pa or less as the upper clad layer 8, and then the pressure is 0.4 MPa. And thermocompression bonding under conditions of a temperature of 50 ° C. and a pressurization time of 30 seconds.
Furthermore, after irradiation with ultraviolet rays (wavelength 365 nm) at 3 J / cm ² , heat treatment was performed at 180 ° C. for 1 hour to cure the upper clad layer 4 and produce the optical waveguide 10.
A 45 ° mirror portion 12 was formed from the upper clad layer 8 side of the obtained optical waveguide 10 using a dicing saw (DAC552, manufactured by Disco Corporation) (see FIG. 1D).

As a protective film with an adhesive for mirror protection, a film in which the adhesive 3 described above was attached to a polyimide film (thickness: 12.5 μm) under the above conditions was used. Using a vacuum pressure laminator (MVLP-500, manufactured by Meiki Seisakusho Co., Ltd.), a protective film with an adhesive is affixed to the mirror forming part under the above conditions, and the adhesive is heated at 180 ° C. for 1 hour. 3 was cured, and a coating 9 for protecting the wiring was provided on the mirror portion 12 (see FIG. 1E). Next, each side was cut by 15 mm from the product size, and the substrate 2 was made into two substrates 1 with optical waveguides (see FIG. 1 (f)).
Here, before the substrate 2 was made into two substrates 1 with an optical waveguide (see FIG. 1 (f)), each side was cut by 15 mm from the product size, and the warpage of the substrate was measured. The method of measuring warpage is that the product is placed on a horizontal surface plate with the convex surface of the substrate in the warp direction, and the maximum gap (gap) generated between the surface plate and the product is defined as a Cygness gauge (manufactured by Tokyo Cycnes Corporation). , For measuring gaps in 0.1 mm increments). As a result, the maximum warpage was 0.9 mm.

[Circuit formation by subtractive method]
Thereafter, a photosensitive dry film resist (trade name: Photec, manufactured by Hitachi Chemical Co., Ltd., thickness: 25 μm) is applied to a copper foil surface of polyimide with a single-sided copper foil, which is a peeled surface of the substrate 1, a roll laminator (Hitachi Chemical Techno Plant). HLM-1500, manufactured by Co., Ltd., was applied under the conditions of pressure 0.4 MPa, temperature 50 ° C., laminating speed 0.2 m / min, and then photosensitized with an ultraviolet exposure machine (manufactured by Oak Manufacturing Co., Ltd., EXM-1172). From the dry film resist side, ultraviolet light (wavelength 365 nm) is irradiated at 120 mJ / cm ² through a negative photomask having a width of 50 μm, and the photosensitive dry film resist in an unexposed portion is 0.1 to 5 wt% sodium carbonate at 35 ° C. Was removed with a dilute solution. Thereafter, using a ferric chloride solution, the exposed copper foil of the photosensitive dry film resist was removed by etching, and exposure was performed using a 1-10 wt% sodium hydroxide aqueous solution at 35 ° C. A portion of the photosensitive dry film resist was removed. Next, a coverlay film (trade name: Nikaflex CISG, manufactured by Nikkan Kogyo Co., Ltd., substrate thickness: 12.5 μm, adhesive thickness: 15 μm) was applied to a pressure of 4.0 MPa, a temperature of 160 ° C., and a pressurization time of 90 minutes. The film was vacuum-pressed under the following conditions to provide a coating 9 for protecting the wiring. As a result, a wiring board on which the electrical wiring 5 and the optical waveguide 10 were formed was obtained. (See Fig. 1 (g))

Example 2
In Example 1, the bonding surfaces of the single-sided copper foil polyimide substrate were reversed (polyimide surfaces), and after bonding, electrical wiring was formed using the above subtractive method, and the coverlay was adhered (FIG. 2 ( c)). Thereafter, the substrate 2 was separated into two substrates 1 on which electrical wiring had been formed, and an optical waveguide was formed on the polyimide surface in the same manner as described above (see FIG. 2G).
Before separating the substrate 2, the amount of warpage was measured in the same manner as in Example 1. As a result, the warp was 1.0 mm at the maximum.

Example 3
(1) Bonding of substrates of polyimide roll with single-sided copper foil (trade name: Iupicel N, manufactured by Ube Nitto Kasei Kogyo Co., Ltd., copper foil thickness: 5 μm, polyimide thickness: 12.5 μm, product width: 250 mm) A 230 mm square release sheet (trade name: Aflex, manufactured by Asahi Glass Co., Ltd., thickness: 30 μm) is installed on the copper foil surface at an interval of 250 mm, and the adhesive 3 obtained by producing the adhesive from above is installed. A roll laminator (manufactured by Hitachi Chemical Technoplant Co., Ltd., HLM-1500) was used and applied under conditions of a pressure of 0.5 MPa, a temperature of 100 ° C., and a laminating speed of 0.2 m / min.
Thereafter, the adhesive 3 is irradiated with 1 J / cm ² of ultraviolet light (wavelength 365 nm) with an ultraviolet exposure machine (EXM-1172, manufactured by Oak Manufacturing Co., Ltd.), and a release PET film (Purex) which is a protective film of the adhesive 3 A31) was peeled off. Next, the adhesive 3 on the release sheet is peeled off together with the release sheet, and the polyimide foil with the same single-sided copper foil as above is laminated on the adhesive surface using the above-described vacuum pressure laminator under the above conditions. And the roll-shaped board | substrate 2 with which the board | substrate 1 was affixed on the product frame part was obtained by heat-hardening at 180 degreeC for 1 hour.
Thereafter, a wiring board on which the electric wiring 5 and the optical waveguide 10 were formed was obtained in the same manner as in Examples 1 (2) and (3).

Comparative Example 1
In Example 1, on the polyimide surface of polyimide with a single-sided copper foil, without bonding the substrates: Upicell N, Ube Nitto Kasei Kogyo Co., Ltd., copper foil thickness: 5 μm, polyimide thickness 12.5 μm) The adhesive 3 described in PCT / JP2008 / 05465 was bonded to the above under the above conditions, and then the release PET film (Purex A31), which is a protective film for the resin film for forming the lower cladding layer, was peeled off. Next, it was affixed on the adhesive surface of the board | substrate obtained above on the same lamination conditions as the above, and the lower clad layer 6 was obtained.
The substrate warpage at this time was measured by the same method as in Example 1. As a result, the maximum warpage was 5.1 mm. The subsequent production of the optical waveguide was interrupted in the process of forming the lower clad layer 6 because there is a possibility that the apparatus might break down.

  According to the method for manufacturing a wiring board of the present invention, it is excellent in suppressing warpage of the substrate, and can be manufactured by stacking two substrates, and is excellent in productivity because there is almost no extra material. In addition, since two substrates can be manufactured by being stacked, it can be handled as an extremely thin wiring board by handling as a substrate having a certain thickness. Moreover, it can respond to both a copper clad laminated board and the board | substrate to which build-up formation is carried out, and a flexible substrate can also respond to roll processing. For this reason, the manufacturing method of this invention is applicable to wide fields, such as a semiconductor package board | substrate, a flexible substrate, and an optoelectric composite member.

1; Substrate 2; Substrate (after bonding)
3; adhesive 4; peeling surface 5; electrical wiring 6; lower cladding layer 7; core pattern 8; upper cladding layer 9; coating 10 for wiring protection; optical waveguide 11;

Claims (8)

  Two substrates are bonded to each other inside the outer periphery of the two substrates with an adhesive within a frame shape of 0.1 to 50 mm to form one substrate, and wiring is provided on both surfaces of the one substrate. The method of manufacturing a wiring board is characterized by separating the one substrate by removing the bonded portion bonded through the adhesive and forming each independent wiring board .   The method for manufacturing a wiring board according to claim 1, wherein wiring is further formed on the separation surface after separating the one substrate.   The method for manufacturing a wiring board according to claim 1, wherein the wiring includes an optical waveguide and electrical wiring.   The wiring is a single-layer electric wiring or a multilayer electric wiring in which a step of forming an electric wiring on the substrate is repeated one or more times after a substrate is laminated on the surface on which the electric wiring is formed. The manufacturing method of the wiring board of Claim 1 or 2.   The method for manufacturing a wiring board according to claim 1, wherein the wiring is one or more optical waveguides.   The method of manufacturing a wiring board according to claim 3 or 4, wherein the electrical wiring is formed using at least one of a subtractive method, an additive method, and a semi-additive method.   6. The method for manufacturing a wiring board according to claim 3, wherein the optical waveguide is an optical waveguide with a mirror.   After wiring is formed on both surfaces of the one substrate, or after wiring is formed on the separation surface after separating the one substrate, the outermost surface wiring is coated with a wiring protection. A method for manufacturing a wiring board according to any one of claims 1 to 7.

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