JP2011029409A - 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, performs processing while maintaining back-to-back manufacture of superior size stability and mass-productivity up to an outermost layer (a laminate surface by the back-to-back manufacture), and can secure higher size stability and operation efficiency. <P>SOLUTION: The method of manufacturing the wiring board includes a step A of putting two substrates together back to back with each other into a first back-to-back substrate; a step B of forming wirings on both surfaces of the first back-to-back substrate; a step C of laminating two or more first back-to-back substrates; a step D of separating the substrates along surfaces put together back to back in the step A and forming a second back-to-back substrate having the two substrates turned over and put together back to back; a step E of forming wirings on both surfaces of the second back-to-back substrate; and a step F of separating the second back-to-back substrate along the surfaces put together back to back in the step D into the two substrates. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention is superior in suppressing warpage of the substrate, and can be processed while maintaining the back-to-back manufacturing with excellent dimensional stability and mass productivity up to the outermost layer (lamination surface by back-to-back), further dimensional stability In addition, the present invention relates to a method of manufacturing a wiring board that can ensure high working efficiency.

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.
Also, a back-to-back method in which two substrates are bonded together as a useful method for ensuring warp suppression, dimensional stability of the substrates, and high work efficiency, and wiring is formed as one apparently thick substrate (Patent Document) 1 and 2) are useful. For example, as described in Patent Document 1, a method of sandwiching two copper foils with a prepreg or a dry film, or as described in Patent Document 2, a method using a release layer on both sides of an adhesive layer. is there.
However, in the back-to-back method described above, it is necessary to form wiring after separating the substrates on the stacked surfaces, and the stress accumulated in the substrate at the time of separation is released, so that the substrate is distorted and the substrate dimensions are unstable. It led to Furthermore, when a thin substrate is used and wiring (optical waveguide or the like) having a high shrinkage rate due to heat or the like is formed on the laminated surface after back-to-back separation, warpage occurs, making it difficult to flow through the production line.

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

  The present invention is excellent in suppressing warpage of the substrate, and can be processed while maintaining the back-to-back manufacturing with excellent dimensional stability and mass productivity up to the outermost layer (lamination surface by back-to-back), further dimensional stability And it aims at providing the manufacturing method of the wiring board which can ensure high working efficiency.

  As a result of intensive studies, the present inventors have made a process A in which two substrates are back-to-back to form a first back-to-back substrate, a process B in which wiring is formed on both surfaces of the first back-to-back substrate, A second back-to-back process in which two or more of the first back-to-back substrates are laminated on the back-to-back surfaces in Step C and Step A, and the two substrates are back-to-back reversed. Step D for forming a substrate, Step E for forming wiring on both surfaces of the second back-to-back substrate, Step F for separating the second back-to-back substrate into the two substrates at the surface back-to-back in Step D The present invention has been completed by finding that the above-described object is achieved by sequentially performing the above-described processes to manufacture a wiring board.

That is, the present invention
(1) Step A in which two substrates are back to back to form a first back-to-back substrate, Step B to form wiring on both surfaces of the first back-to-back substrate, and two first back-to-back substrates Step D for forming the second back-to-back substrate which is separated from the back-to-back surfaces in the step C and the step A to be laminated and the two substrates are turned back to back. A wiring board comprising: a step E of forming wiring on both surfaces of the back-to-back substrate; and a step F of separating the second back-to-back substrate into the two substrates on the surface back-to-back in step D. Production method,
(2) In the step C, two dummy plates are laminated on the outermost layer, and in the step D, in addition to the second substrate, a substrate laminated on each of the two dummy plates is formed, The method for manufacturing a wiring board according to (1), wherein the dummy plate is separated from the substrate laminated on each of the two dummy plates in step F,
(3) In step A, a dummy plate is stacked on each of the two substrates in addition to the first back-to-back substrate, and in step B, the dummy plate is stacked in addition to the first back-to-back substrate. A wiring is formed on the opposite side of the dummy board lamination surface of the two boards, and the two boards laminated with the dummy board on the front and back of the one or more first back-to-back boards in the step C are dummy. The method for producing a wiring board according to (1), wherein the second back-to-back substrate and the dummy plate are separated in the step D, the step of laminating the plates on the outside,
(4) The method for producing a wiring board according to any one of (1) to (3), wherein the wiring is covered with a coating for protecting the wiring.
(5) The method for manufacturing a wiring board according to any one of (1) to (4), wherein the wiring includes an optical waveguide and electrical wiring.
(6) The wiring is a single-layer electrical wiring or a multilayer electrical wiring in which a step of forming an electrical wiring on the substrate is repeated one or more times after a substrate is laminated on the surface on which the electrical wiring is formed. A method for manufacturing a wiring board according to any one of (1) to (4),
(7) The method for manufacturing a wiring board according to any one of (1) to (4), wherein the wiring is one or more optical waveguides,
(8) The method for manufacturing a wiring board according to (5) or (6), wherein the electrical wiring is formed using at least one of a subtractive method, an additive method, and a semi-additive method,
(9) The method for manufacturing a wiring board according to (5) or (7), wherein the optical waveguide is an optical waveguide with a mirror.

  According to the method for manufacturing a wiring board of the present invention, processing with back-to-back that is excellent in suppressing warpage of the substrate and excellent in dimensional stability and mass productivity is performed while maintaining the outermost layer (lamination surface by back-to-back). Therefore, it is possible to manufacture a wiring board capable of ensuring further dimensional stability and high work efficiency.

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

  For example, as shown in FIG. 1 (h), the wiring board manufactured according to the present invention is an optical waveguide in which a lower cladding layer 6, a core pattern 7 and an upper cladding layer 8 are laminated on an electrical wiring 5 in this order. 10 is a laminated board, as shown in FIG. 1 (f) and FIG. 3 (h), a board on which electric wiring is formed on both sides, or a multilayer board thereof.

(Process A: First back-to-back manufacturing method)
As long as the first back-to-back substrate 2 is formed by back-to-back, the back-to-back method is not particularly limited. For example, the substrates 1 are bonded to each other using a removable adhesive 3. As shown in FIG. 1 (a), a release sheet 14 is disposed on both sides of the adhesive 3 or the support 16 with the adhesive 3 applied on the front and back sides of the product workpiece to form an adhesive 3 with a core. The two substrates 1 are laminated at the frame portion via the adhesive 3 to form the substrate 2, or the two substrates are applied only to the frame portion of the substrate 1 with the varnish-like or film-like adhesive 3. This is a method in which 1 is back-to-back and the center part of the product is a non-adhesive part. For back-to-back, hand bonding, press, vacuum press, roll laminator, vacuum laminator and the like are preferable, and when there is a heating step in the subsequent step, it is more preferable to use a vacuum press or a vacuum laminator.

(Process B: Method of forming wiring on both surfaces of the first back-to-back substrate)
〔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 it allows easy formation of fine wiring.

[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]
When the surface on which the electric wiring 5 is formed has an adhesive function, the seed layer can 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 alkaline etching solution, nickel is removed with a nickel etching solution, and the latter is made of aluminum, copper, insulating resin or the like as a carrier. A peelable copper foil or the like 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 of the wiring board obtained as a final product (wiring surface located in the outermost layer) as a coating 9 for protecting the wiring. 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.

(Process C: Manufacturing method of second back-to-back substrate)
In the step C of laminating the first back-to-back substrates 2, there is no particular limitation on the laminating method as long as peeling does not occur between the laminated surfaces in the step C. For example, a releasable adhesive 3 is used to attach the entire surface of the substrate 2 and the support 16, or as shown in FIG. 1C, the substrates 2 are bonded to each other through the adhesive 3 at a part inside the product workpiece, The substrate 2 and the support 16 can be laminated by applying only to the frame portion of the single-sided substrate 2 to be laminated with the varnish-like or film-like adhesive 3 shown in the column “Back-to-back method of substrates”. As the laminating method, hand bonding, press, vacuum press, roll laminator, vacuum laminator and the like are preferable, and when there is a heating step in the subsequent step, it is more preferable to use a vacuum press or a vacuum laminator. The number of stacked layers is not particularly limited, but is preferably adjusted as appropriate depending on the thickness of the product acceptable in the production line and the workability of cutting the first back-to-back substrate 2 stacked in Step D.

(Process D: First back-to-back substrate separation method)
Of the methods mentioned in the back-to-back method for the two substrates 1, the two substrates 1 are back-to-back using the re-peelable adhesive 3, and the re-peelable adhesive 3 is also used in step C. In the case where the adhesive strength of the adhesive 3 used for the lamination between the substrates 2 is stronger than the adhesive strength of the adhesive 3 used in the back-to-back method of the two substrates 1, the separation of the process D and the process F is performed. Can be performed sequentially. When the substrates 1 are back-to-back using the adhesive 3 only in the frame portion of the methods mentioned in the back-to-back method of the substrate 1 and bonding is also performed in the process C using the adhesive only in the frame portion. It is preferable to use the first back-to-back substrate 2 in which the size of the non-bonded portion is larger than the size of the non-bonded portion in Step C. This is because when the first back-to-back substrate 2 is separated, the non-bonded portion is cut between the substrates 1 and the bonded portion is cut between the first back-to-back substrates 2 so that the process D can be easily performed. It is to do.

(Process E: Method of forming wiring on both surfaces of the second back-to-back substrate)
The method for forming the wiring on both surfaces of the second back-to-back substrate 4 in the step E may be performed in the same manner as the method for forming the wiring on both surfaces of the first back-to-back substrate in the step B described above.

(Process F: Second back-to-back substrate separation method)
When the second back-to-back substrate 4 uses the removable adhesive 3, the two substrates may be peeled off from the interface of the removable adhesive 3. Further, when the substrates are back-to-back using the adhesive 3 only on the frame portion, the two back-to-back substrates 4 can be cut by cutting the second back-to-back substrate 4 in a range smaller than the size of the non-bonded portion at the center of the substrate. It can be a substrate.

(Dummy plate stacking method)
The lamination method of the dummy plate 13 can be performed by the method shown in the column of (Step A: Method of Backing Two Substrates). Since there is no pair of substrates in the outermost substrate 1 in the step D, an object is to stack dummy plates and ensure their dimensional stability.

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.

[Support as core of back-to-back substrates]
When the support 16 is used between the substrates 1 in the back-to-back method of the two substrates 1 in step A, or when the support 16 is used between the first back-to-back substrates 2 in step C, the type of the support 16 For example, a metal plate, an FR-4 substrate, a polyimide substrate, a semiconductor substrate, a silicon substrate, a glass substrate, or the like can be used, and a metal layer is provided on one or both sides thereof. It may be a laminated board or a laminated board of the substrates listed above. Further, an adhesive that becomes a rigid substance by curing may be used. Preferable examples of adhesives that exhibit rigidity upon curing include prepregs, build-up materials, and thermosetting adhesives. The thickness of the support may be appropriately changed depending on the thickness of the release material to be used and the required dimensional stability, but is preferably 5 μm to 1 cm, and sufficient handling properties are obtained when the thickness is 50 μm to 1 mm. .

[Dummy plate]
The type of the dummy plate 13 is not particularly limited. For example, an FR-4 substrate, a build-up substrate, a polyimide substrate, a semiconductor substrate, a silicon substrate, a glass substrate, or the like can be used. The laminated board in which the metal layer 11 is installed on both surfaces may be sufficient. Further, it may be a flexible flexible material or a non-flexible hard material.
Further, by using a film as the dummy plate 13, 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. It is preferable to use a material having the same warp and dimensional behavior as those of the substrate 1 in the process.

〔adhesive〕
Although it does not specifically limit to the adhesive agent 3, A double-sided tape, a hot-melt-adhesive agent, a 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.

[Release sheet]
The type of the release sheet 14 is not particularly limited. For example, a release sheet for press, a releasable resin or adhesive, a UV or heat releasable resin, and the like can be used. .
Further, the film-like material for the release sheet 14 is not particularly limited, but polyester such as copper foil, silver foil, gold foil, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polyethylene, polypropylene, polyamide, polycarbonate, polyphenylene ether. Preferable examples include polyether sulfide, polyarylate, liquid crystal polymer, polysulfone, polyether sulfone, polyether ether ketone, polyether imide, polyamide imide, and polyimide. From the viewpoint of heat resistance and releasability from the substrate, copper foil, polyimide film, and aramid film are more preferable.
The thickness of the film may be appropriately changed depending on the intended flatness and embedding property of the electric wiring 5, but is preferably 5 to 250 μm.

[Method of forming optical waveguide]
Hereinafter, the manufacturing method of the wiring board of the present invention in which the optical waveguides are formed on both surfaces of the first back-to-back substrate 2 will be described in detail (see FIG. 1).
First, as shown in FIG. 1 (e) -1, a lower clad layer 6 is provided on both surfaces of a substrate 2, and a core pattern 7 is formed thereon. Further, an upper clad layer 8 is laminated to form a mirror part (see FIG. 1 (f) -1). When the first back-to-back substrate 2 and the lower clad layer 6 do not have an adhesive force, 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 first back-to-back 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 after performing prebaking, it can form by irradiating an ultraviolet-ray and hardening a thin film. 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 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.

[Production of adhesive described in PCT / JP2008 / 05465]
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
[Creation of the first back-to-back substrate]
140 mm square release sheet 14 (trade name: Aflex, Asahi Glass Co., Ltd.) at the center of both sides of prepreg (trade name: GEA-679FG, manufactured by Hitachi Chemical Co., Ltd., thickness: 40 μm) as the adhesive 3 and the support 16 Company made, thickness: 30 μm), 150 mm square polyimide foil with single-sided copper foil as the substrate 1 on both sides (trade name: Iupicel N, Ube Nitto Kasei Kogyo Co., Ltd., copper foil thickness: 5 μm, polyimide thickness 12.5μm) is placed so that the polyimide surface is on the release sheet side, evacuated to 4 kPa or less, then heated and laminated under the conditions of pressure 2.5 MPa, temperature 180 ° C., pressurization time 1 hour. A first back-to-back substrate 2 was created (see FIG. 1A).

[Circuit formation by subtractive method]
Photosensitive dry film resist (trade name: Photec, manufactured by Hitachi Chemical Co., Ltd., thickness: 25 μm) on the copper foil on both sides of the first back-to-back substrate, roll laminator (manufactured by Hitachi Chemical Technoplant Co., Ltd., HLM-1500) With a pressure of 0.4 MPa, a temperature of 110 ° C., and a laminating speed of 0.4 m / min, and then with a UV exposure machine (manufactured by Oak Manufacturing Co., Ltd., EXM-1172) having a width of 50 μm from the photosensitive dry film resist side. Ultraviolet light (wavelength 365 nm) was irradiated through a negative photomask at 120 mJ / cm ^2, and the unexposed photosensitive dry film resist was removed with a dilute solution of 0.1 to 5 wt% sodium carbonate at 35 ° C. 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, and an electrical wiring 5 was formed. 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 first back-to-back substrate having electrical wirings 5 formed on both sides of the substrate was obtained (see FIG. 1B).
The warpage of the obtained substrate 1 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 0.2 mm.

[Lamination of the first back-to-back substrate]
Three pieces of the above first back-to-back substrate 2, prepreg (trade name: GEA-679FG, manufactured by Hitachi Chemical Co., Ltd., thickness: 40 μm) and copper foil (trade name: trade name: 3EC-VLP, manufactured by Mitsui Mining & Smelting Co., Ltd., thickness: 12 μm) was prepared. When the three first back-to-back substrates 2 are the center, and the dummy plates are arranged on both sides, each substrate (between the first back-to-back substrates 2 and the first back-to-back) A prepreg similar to the above is placed between the substrate 2 and the dummy plate, and a 130 mm square release sheet 14 similar to the above is installed in the center of both surfaces of the prepreg, and heated and laminated under the same conditions as above (FIG. 1 (c) )reference).

[Creation of second back-to-back substrate]
The center of the substrate obtained above is cut into a 135 mm square, and two second back-to-back substrates 4 with both surfaces being polyimide surfaces and two substrates 1 with dummy plates having one surface being a polyimide surface. Obtained.

[Production of resin film for clad layer formation]
(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.

[Production of optoelectric composite member (wiring board combined with optical waveguide)]
A method for producing the photoelectric composite member will be described below.
PCT / JP2008 / 05465 are applied to the polyimide surface of the two second back-to-back substrates 4 having both surfaces made of polyimide and the two substrates 1 with dummy plates having one surface made of polyimide. The adhesive surface of the described adhesive 3 was laminated using a roll laminator (manufactured by Hitachi Chemical Technoplant Co., Ltd., HLM-1500) under conditions of a pressure of 0.4 MPa, a temperature of 50 ° 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 which is a protective film of the adhesive 3 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 clad layer obtained above, is peeled off, and the same lamination conditions as above are applied to the adhesive surface of the substrate obtained above. By applying 1.5 J / cm ^{2 of} ultraviolet rays (wavelength 365 nm) from the resin side with an ultraviolet exposure machine (manufactured by Oak Manufacturing Co., Ltd., EXM-1172), and then heat-treating at 80 ° C. for 10 minutes, A lower cladding 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).

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 6, 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.
Further, 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 8 and produce the optical waveguide 10 (FIG. 1 (e) -1 and FIG. 1). (See (e) -2).
A 45 ° mirror portion 12 was formed from the upper clad layer 6 side of the obtained optical waveguide 10 using a dicing saw (DAC552, manufactured by Disco Corporation) (FIGS. 1 (f) -1 and 1 (f)). -2).

As a protective film with an adhesive for mirror protection, a film in which the adhesive 3 described in PCT / JP2008 / 05465 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, 15 mm each side was cut from the product size to obtain a substrate 1 laminated on two second back-to-back substrates 4 and two dummy plates 13 (FIG. 1 (g) -1 and FIG. 1 (g) ) -2).
The warpage of the wiring board having the electrical wiring 5 on one side and the two-layer optical waveguide 10 on the other side was measured. The method for measuring warpage was the same as in Example 1. As a result, the maximum warpage was 0.3 mm.

[Separation of second back-to-back substrate and dummy plate]
The two back-to-back substrates with the optical waveguide 10 formed on the polyimide surface and the center of the two substrates 1 with the dummy plates 13 are cut to 125 mm square, and the second back-to-back substrate is separated. The separation of the dummy plates was performed respectively. Thus, a wiring board having the electrical wiring 5 on one side and the optical waveguide 10 on the other side was obtained (see FIGS. 1 (h) -1 and 1 (h) -2).

Example 2
After the first back-to-back substrate was formed by reversing the bonding surfaces of the single-sided copper foil polyimide substrate (copper foil surfaces) in Example 1, the upper cladding was formed using the same method of manufacturing the optical waveguide 10 as described above. The layer 8 was exposed until the core pattern 7 and the upper clad layer 8 were formed on the upper clad layer 8, and the first back-to-back substrate 2 having two optical waveguides 10 formed on both sides was formed. Further, two layers of the mirror portion 12 were simultaneously formed by the same method as in Example 1. The mirror part 12 was protected in the same manner as in Example 1 to form the optical waveguide 10 (see FIG. 2A). Thereafter, the second back-to-back substrate 4 and the substrate 1 with the dummy plate 13 are prepared in the same manner as in Example 1, and the electrical wiring 5 is formed on the copper foil surface of the copper foil with single-sided polyimide. Separation of the laminated substrate 4 and the dummy plate were performed to obtain a wiring board having electric wiring 5 on one side of six sheets and two layers of optical waveguides 10 on the other side (see FIG. 2B). .
The warpage of the wiring board having the electrical wiring 5 on one side and the two-layer optical waveguide 10 on the other side was measured. The method for measuring warpage was the same as in Example 1. As a result, the maximum warpage was 0.3 mm.

Example 3
[Lamination of the first back-to-back substrate]
150 mm square prepreg (trade name: GEA-679FG, manufactured by Hitachi Chemical Co., Ltd., thickness: 40 μm) on both sides 140 mm square copper foil (trade name: 3EC-VLP, manufactured by Mitsui Mining & Smelting Co., Ltd., thickness: 18mm) in the center, 150mm square copper foil (trade name: 3EC-VLP, manufactured by Mitsui Mining & Smelting Co., Ltd., thickness: 12µm), 150mm square prepreg (trade name: GEA-679FG, Hitachi) After sequentially forming a copper foil of 150 mm square (trade name: 3EC-VLP, manufactured by Mitsui Mining & Smelting Co., Ltd., thickness: 12 μm) made by Kasei Kogyo Co., Ltd., thickness: 40 μm, vacuuming to 4 kPa or less, Heat lamination was performed under the conditions of a pressure of 2.5 MPa, a temperature of 180 ° C., and a pressing time of 1 hour to obtain a first back-to-back substrate 2 (see FIG. 3A-1). In addition, three first back-to-back substrates 2 were prepared by the above manufacturing method.
The warpage of the obtained first back-to-back substrate 2 was measured. The method for measuring warpage was the same as in Example 1. As a result, the maximum warpage was 0.2 mm.

[Lamination of substrates with dummy plates]
Separately from the first back-to-back substrate 2, a 150 mm square prepreg (trade name: GEA-679FG, manufactured by Hitachi Chemical Co., Ltd., thickness: 40 μm) on one side is a 150 mm square copper foil (trade name: 3EC-VLP). , Mitsui Mining & Smelting Co., Ltd., thickness: 18 μm), 140 mm square copper foil (trade name: 3EC-VLP, Mitsui Kinzoku Mining Co., Ltd., thickness: 18 μm) is placed in the center of the product, 140 mm 150 mm square copper foil (trade name: 3EC-VLP, manufactured by Mitsui Mining & Smelting Co., Ltd., thickness: 12 μm), 150 mm square prepreg (trade name: GEA-679FG, manufactured by Hitachi Chemical Co., Ltd.) (Thickness: 40 μm), 150 mm square copper foil (trade name: 3EC-VLP, manufactured by Mitsui Mining & Smelting Co., Ltd., thickness: 12 μm) is further constructed, heated and laminated in the same manner as above, and the dummy plate 13 The attached substrate 1 was created (see FIG. 3A-2). Further, two substrates 1 with dummy plates 13 were prepared by the above manufacturing method.

[Electric wiring formation]
In the same manner as in Example 1, electrical wirings 5 were formed on both surfaces of the three first back-to-back substrates 2 and on the 12 μm copper foil side of the two substrates 1 with dummy plates 13 (FIG. 3B). -1 and FIG. 3 (b) -2).
Next, a 150 mm square prepreg (trade name) as the support 16 and the adhesive 3 is formed on both surfaces of the three first back-to-back substrates 2 and the surface on which the electric wiring 5 of the two substrates 1 with dummy plates is formed. : GEA-679FG, manufactured by Hitachi Chemical Co., Ltd., thickness: 40 μm), 150 mm square copper foil (trade name: 3EC-VLP, manufactured by Mitsui Mining & Smelting Co., Ltd., thickness: 12 μm), further comprising the above Heat lamination was performed in the same manner as the conditions (see FIGS. 3C-1 and 3C-2). Thereafter, the electrical wiring 5 was formed on the outermost 12 μm copper foil in the same manner as described above (see FIGS. 3D-1 and 3D-2).

[Creation of second back-to-back substrate]
Three first back-to-back substrates centered on the three first back-to-back substrates 2 so that the surface on which the electric wiring 5 is not formed on the two substrates 1 with the dummy plates 13 are the outermost surfaces. The first back-to-back substrate 2 was stacked in the same manner as in Example 1 with the layer configuration between the substrates 2 and 2 (see FIG. 3E). Further, the product was cut into a 135 mm square by the same method as in Example 1 to obtain four second back-to-back substrates 4 (see FIG. 3F). Thereafter, electrical wirings 5 were formed on both surfaces of the second back-to-back substrate 4 by the same method as in Example 1 (see FIG. 3G).
The warpage of the obtained second back-to-back substrate 4 was measured. The method for measuring warpage was the same as in Example 1. As a result, the maximum warpage was 0.4 mm.

[Separation of second back-to-back substrates]
Similarly to Example 1, the product center was cut into a 125 mm square, and the second back-to-back substrate 4 was separated to obtain eight multilayer wiring boards (see FIG. 3H).

Comparative Example 1
In Example 1, after making the first back-to-back substrate and forming the circuit by the subtractive method, the substrate 1 is cut by 1.5 cm from the outer periphery of the product workpiece, and the flexible electric circuit having electric wiring on one side of two sheets A wiring board was used. Thereafter, the adhesive 3 described in PCT / JP2008 / 05465 is bonded to the polyimide surface 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, is peeled off, The lower clad layer 6 was obtained by pasting on the adhesive surface of the substrate obtained above under the same laminating conditions as above.
The substrate warpage at this time was measured by the same method as in Example 1. As a result, the maximum warpage was 6.4 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.

  The present invention is excellent in suppressing warpage of the substrate, and can be processed while maintaining the back-to-back manufacturing with excellent dimensional stability and mass productivity up to the outermost layer (lamination surface by back-to-back), further dimensional stability And it aims at providing the manufacturing method of the wiring board which can ensure high working efficiency. Moreover, since it can respond to both a copper-clad laminate and a substrate to be built up, it can be applied to a wide range of fields such as a semiconductor package substrate, a flexible substrate, and an optoelectric composite member.

DESCRIPTION OF SYMBOLS 1; Substrate 2; First back-to-back substrate 3; Adhesive 4; Second back-to-back substrate 5; Electrical wiring 6; Lower clad layer 7; Core pattern 8; Upper clad layer 9; Optical waveguide 11; Metal layer 12; Mirror part 13; Dummy plate 14; Release sheet 15; Separation surface 16: Support

Claims (9)

  Step A in which two substrates are back-to-back to form a first back-to-back substrate, Step B in which wiring is formed on both surfaces of the first back-to-back substrate, and two or more of the first back-to-back substrates are stacked. Step D, separation of the back-to-back surfaces in Step C and Step A, and formation of a second back-to-back substrate in which each of the two substrates is turned back-to-back, and the second back-to-back A method of manufacturing a wiring board, comprising: a step E of forming wiring on both sides of the substrate; and a step F of separating the second back-to-back substrate into the two substrates on the surface back-to-back in step D.   In step C, two dummy plates are laminated on the outermost layer, and in step D, a substrate laminated on each of the two dummy plates is formed in addition to the second substrate. The method of manufacturing a wiring board according to claim 1, wherein the dummy plate is separated from a substrate laminated on each of the two dummy plates.   In the step A, a dummy plate is laminated on each of the two substrates in addition to the first back-to-back substrate, and in step B, the two pieces laminated on the dummy plate in addition to the first back-to-back substrate Wiring is formed on the surface opposite to the dummy plate lamination surface of the substrate, and the two substrates laminated with the dummy plate on the front and back of the one or more first back-to-back substrates in the step C are disposed outside the dummy plate. The method of manufacturing a wiring board according to claim 1, wherein the second back-to-back substrate and the dummy plate are separated in the step D.   The method for manufacturing a wiring board according to claim 1, wherein a coating for protecting the wiring is applied to the wiring.   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 in any one of Claims 1-4.   The method for manufacturing a wiring board according to claim 1, wherein the wiring is one or more optical waveguides.   The method for manufacturing a wiring board according to claim 5 or 6, wherein the electrical wiring is formed using at least one of a subtractive method, an additive method, and a semi-additive method.   8. The method for manufacturing a wiring board according to claim 5, wherein the optical waveguide is an optical waveguide with a mirror.

Images