JP2013045858A - Coreless multilayer wiring board and manufacturing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of a coreless multilayer wiring board which is capable of improving adhesive strength with a metal layer which forms a circuit independent of an anchor effect and in which warpage occurrence is reduced, and to provide a coreless multilayer wiring board.SOLUTION: A manufacturing method of a coreless multilayer wiring board includes a lamination step of bonding an insulating resin layer of an insulating film composed of an adhesion layer Aand the insulating resin layer onto the adhesion layer Xof a copper foil film in which the adhesion layer Xis formed on a peelable copper foil, performing curing processing, and laminating these films. After the above lamination step, this method further includes (1) a circuit formation step of forming a circuit on the adhesion layer Aby a semi-additive method; and (2) a copper foil peeling step of peeling a copper foil of the copper foil film, a via hole formation step of forming a via hole in a prescribed position of the adhesion layer Xafter peeling the copper foil, and a circuit formation step of forming a circuit on the adhesion layer Xby the semi-additive method after forming the via hole. There is also provided a coreless multilayer wiring board.

Description

  The present invention relates to a multilayer wiring board having a coreless structure and a method for manufacturing the same.

  A multilayer wiring board is manufactured as follows, for example. First, a prepreg (a material in which a glass cloth is impregnated with an epoxy resin and made into a semi-cured state) is laminated with a copper foil and laminated and integrated by hot pressing on an insulating substrate having an inner layer circuit formed on one side or both sides. Then, a hole called a through hole for interlayer connection is made with a drill, and electroless plating is performed on the inner wall of the through hole and the copper foil surface. At this time, if necessary, electrolytic plating is further performed to obtain a thickness necessary for the circuit conductor. In general, a multilayer wiring board is manufactured by removing unnecessary copper.

  However, in recent years, electronic devices have been further reduced in size, weight, and functionality, and along with this, LSIs and chip components have been highly integrated, and their forms have rapidly changed to multiple pins and downsizing. ing. For this reason, in order to improve the packaging density of electronic components, multilayer wiring boards are being developed for fine wiring. As a method of manufacturing a multilayer wiring board that meets these requirements, a build-up method is used in which an insulating resin that does not contain glass cloth is used as an insulating layer instead of a prepreg, and a wiring layer is formed while connecting only necessary portions with via holes. There is a way. According to this method, the multilayer wiring board can be reduced in weight, reduced in size and miniaturized, and such a manufacturing method is becoming mainstream in the future.

  As a manufacturing method of such a build-up type multilayer wiring board, an insulating resin film is laminated on an inner circuit board, cured by heating, then a via hole is formed by laser processing, and roughened by alkali permanganate treatment, etc. There has been proposed a method of manufacturing by performing a treatment and a smear treatment and performing electroless copper plating to form a via hole capable of interlayer connection with a second circuit (see, for example, Patent Documents 1 to 3). Here, the adhesive strength between the insulating resin and the electroless copper plating is ensured by the roughness of the resin surface (anchor effect), and the surface roughness Ra is as large as 0.5 μm or more. .

  In recent years, various methods have been studied for a coreless structure substrate in which all layers are formed of an insulating film without using a core substrate for the purpose of inexpensively manufacturing a thin and high-density circuit (for example, Patent Documents 4 and 5).

  Furthermore, an insulating film having a two-layer structure of an adhesive layer containing an electroless copper plating catalyst and an insulating resin layer is also disclosed for the purpose of ensuring sufficient adhesion between the electroless copper plating and the resin. (For example, see Patent Document 6).

Japanese Patent No. 3290296 Japanese Patent No. 3654851 Japanese Patent No. 378549 Japanese Patent No. 3935456 Japanese Patent No. 4126052 Japanese Patent No. 2579960

  However, in the multilayer wiring board of the build-up method, further miniaturization of the circuit is required with the recent miniaturization and high density of the semiconductor package. In such a situation, a fine circuit having a size of 10 μm or less is obtained by a method of securing an adhesive force with electroless copper plating using a large roughened shape (anchor effect) obtained by roughening the surface as in the prior art. Short circuit defects and open defects occur, making it impossible to manufacture with good yield. On the other hand, if the roughened shape is reduced, the adhesive force with the electroless copper plating is reduced, and defects such as line peeling occur. For this reason, the insulating resin film which shows electroless copper plating and high adhesive force on the smooth surface was needed.

  Further, even in a coreless structure substrate such as Patent Document 5, it is not assumed that an insulating film having a two-layer structure composed of an adhesive layer that expresses high adhesion on a smooth surface and an insulating resin layer is used. The use of this insulating film has a problem in that an asymmetric structure is obtained, an adhesive layer cannot be provided on both surfaces of the outermost layer, and a warp caused by the asymmetric structure occurs.

  Furthermore, since the film described in Patent Document 6 is not intended to smooth the roughened surface shape and contains a plating catalyst, it is an insulating reliability as a substrate for a semiconductor package of finer dimensions in recent years. Was insufficient.

  In such a situation, the present invention is capable of improving the adhesive force with a metal layer (electroless copper plating) that forms a circuit without depending on the anchor effect, and a coreless structure multilayer in which the occurrence of warpage is reduced. It aims at providing the manufacturing method of a wiring board, and the coreless structure multilayer wiring board obtained by the said manufacturing method.

  As a result of studying to solve such problems, the present inventors have arrived at the present invention described below and found that the problem can be solved. That is, the present invention is as follows.

[1] on the adhesive layer X ¹ of a copper foil film adhesive layer X ¹ is formed on the peelable copper foil, the insulating resin layer of an insulating film composed of the adhesive layer A ¹ and the insulating resin layer A manufacturing method of a coreless structure multilayer wiring board including a laminating step of laminating these films by laminating and curing, and including the following steps (1) and (2) after the laminating step.
(1) Circuit forming step for forming a circuit on the adhesive layer A ¹ by a semi-additive method (2) Copper foil peeling step for peeling the copper foil of the copper foil film, and predetermined adhesive layer X ¹ after peeling the copper foil A via hole forming step for forming a via hole at a position, and a circuit forming step for forming a circuit on the adhesive layer X ¹ by a semi-additive method after forming the via hole

[2] On the adhesive layer A ¹ on which the circuit after the circuit forming step (1) is formed,
(A) a laminating step in which the insulating resin layer of the insulating film composed of the adhesive layer A ² and the insulating resin layer is bonded, and subjected to a curing treatment to be laminated;
(B) a via hole forming step of forming a via hole at a predetermined position of the adhesive layer A ² ;
(C) a circuit forming step of forming a circuit on the adhesive layer A ² by a semi-additive method;
The method of manufacturing a coreless structure multilayer wiring board according to [1], wherein the steps (A) to (C) are sequentially included at least once.

[3] On the adhesive layer X ¹ on which the circuit after the circuit forming step (2) is formed,
(A) a laminating step in which the insulating resin layer of the insulating film composed of the adhesive layer A ² and the insulating resin layer is bonded, and subjected to a curing treatment to be laminated;
(B) a via hole forming step of forming a via hole at a predetermined position of the adhesive layer A ² ;
(C) a circuit forming step of forming a circuit on the adhesive layer A ² by a semi-additive method;
The method of manufacturing a coreless structure multilayer wiring board according to [1] or [2], wherein the steps (A) to (C) are sequentially included at least once.

[4] Each of the adhesive layers X ¹ and A ¹ includes (A) an epoxy resin, (B) an epoxy resin curing agent, (C) a polyamide resin, a polyamideimide resin, a polyethersulfone resin, or crosslinked rubber particles. The method for producing a coreless structure multilayer wiring board according to [1].
[5] The adhesive layer A ² is composed of (A) an epoxy resin, (B) an epoxy resin curing agent, (C) a polyamide resin, a polyamideimide resin, a polyethersulfone resin, or crosslinked rubber particles. [4] The method for producing a coreless structure multilayer wiring board according to any one of [4].

[6] A coreless structure multilayer wiring board manufactured by the coreless structure multilayer wiring board manufacturing method according to any one of [1] to [5].
[7] The coreless structure multilayer wiring board according to [6], wherein the surface roughness Ra of the adhesive layer after removing a part of the circuit formed on at least one surface by etching is 0.3 μm or less.

  According to the present invention, it is possible to improve the adhesive force with a metal layer (electroless copper plating) that forms a circuit without depending on the anchor effect, and manufacture of a coreless structure multilayer wiring board with reduced warpage The coreless structure multilayer wiring board obtained by the method and the manufacturing method can be provided. Moreover, in this invention, since a multilayer wiring board can be manufactured without using the core board | substrate conventionally required for manufacture, the cost resulting from use of a core board | substrate can be reduced.

It is process sectional drawing which shows a part in one aspect | mode of the manufacturing method of the coreless structure multilayer wiring board of this invention schematically. It is process sectional drawing which shows a part in one aspect | mode of the manufacturing method of the coreless structure multilayer wiring board of this invention schematically. It is process sectional drawing which shows a part in one aspect | mode of the manufacturing method of the coreless structure multilayer wiring board of this invention schematically. It is process sectional drawing which shows a part in one aspect | mode of the manufacturing method of the coreless structure multilayer wiring board of this invention schematically.

The manufacturing method of the coreless structure multilayer wiring board according to the present invention includes an adhesive layer A ¹ and an insulating resin layer on an adhesive layer X ¹ of a copper foil film in which an adhesive layer X ¹ is formed on a peelable copper foil. An insulating resin layer of the insulating film to be formed, and a laminating step of laminating these films by performing a curing process, and the following steps (1) and (2) are included after the laminating step.
(1) Circuit forming step for forming a circuit on the adhesive layer A ¹ (2) Copper foil peeling step for peeling the copper foil of the copper foil film, and vias are formed at predetermined positions on the adhesive layer X ¹ after peeling the copper foil a via forming step of, in the following circuit formation step of forming a circuit on the adhesive layer X ¹ after the via formation, describes the materials initially forming the member and each layer, followed by a description of the above steps.

(Copper foil film)
Copper film adhesive layer X ^1, which are formed on a peelable foil.
Adhesive layers including the adhesive layer X ¹ (adhesive layers X ¹ , A ¹ , A ² and other adhesive layers formed for the same purpose as these adhesive layers, hereinafter referred to as “adhesive layer” The adhesive layer resin composition for forming (A) a polyfunctional epoxy resin (hereinafter sometimes referred to as “component (A)”), (B) an epoxy resin curing agent ( Hereinafter, it may be referred to as “component (B)”, (C) polyamide resin, polyamideimide resin, polyethersulfone resin, or crosslinked rubber particles (hereinafter also referred to as “component (C)”). Is preferred.

  The polyfunctional epoxy resin as component (A) is an epoxy resin having two or more epoxy groups in the molecule, such as a phenol novolac epoxy resin, a cresol novolac epoxy resin, an aralkyl epoxy resin, and the like. It is done. In particular, it is preferable to include an aralkyl novolac type epoxy resin or an aralkyl novolac type epoxy resin. The aralkyl novolac type epoxy resin in the present invention is preferably an aralkyl novolak type epoxy resin having a biphenyl structure. The novolak-type epoxy resin having a biphenyl structure refers to an aralkyl novolak-type epoxy resin containing an aromatic ring of a biphenyl derivative in the molecule. For example, the following formula (1) (wherein p is 1 ≦ p ≦ 5 (preferably satisfying 1.5 ≦ p ≦ 3). These may be used alone or in combination of two or more.

  As commercial products of the epoxy resin represented by the formula (1), NC-3000 (p in the above formula (1) is 1.7), NC-3000-H (the above formula (1)) manufactured by Nippon Kayaku Co., Ltd. P is 2.8). (A) It is preferable that the compounding quantity of a component is 20-60 mass% in the ratio in the total solid of the resin composition except a solvent. By setting the blending amount of the component (A) to 20% by mass or more, a decrease in solder heat resistance can be suppressed, and by setting it to 60% by mass or less, the adhesive strength with the circuit conductor can be kept good.

  As the epoxy resin curing agent as component (B), various phenol resins, acid anhydrides, amines, hydragits and the like can be used. As the phenol resin, a novolac type phenol resin, a resol type phenol resin, or the like can be used. As the acid anhydrides, phthalic anhydride, benzophenone tetracarboxylic dianhydride, methyl hymic acid and the like can be used. As the amines, dicyandiamide, diaminodiphenylmethane, guanylurea and the like can be used. In order to improve the reliability, it is preferably a novolac type phenol resin, and when it is a triazine ring-containing novolac type phenol resin, the peel strength of the metal foil and the peel strength of the electroless plating after chemical roughening are low. It is improved and more preferable.

  The triazine ring-containing novolak type phenol resin in the present invention refers to a novolak type phenol resin containing a triazine ring in the main chain of the novolak type phenol resin, and may be a cresol novolak type phenol resin containing a triazine ring. The nitrogen content is preferably 10 to 25% by mass and more preferably 12 to 19% by mass in the triazine ring-containing novolac type phenol resin. When the nitrogen content in the molecule is within this range, the adhesion and heat resistance will be good. As the triazine ring-containing novolac type phenol resin, one having a number average molecular weight of 500 to 600 can be used. These may be used alone or in combination of two or more.

The triazine ring-containing novolac type phenol resin can be obtained by reacting phenol, an aldehyde, and a triazine ring-containing compound under conditions of pH 5-9. When cresol is used instead of phenol, a triazine ring-containing cresol novolac type phenol resin is obtained. Any of o-, m-, and p-cresol can be used as the cresol, and melamine, guanamine and derivatives thereof, cyanuric acid and derivatives thereof can be used as the triazine ring-containing compound.
As a commercial item, the triazine ring containing novolak type phenol resin phenolite LA-1356 (nitrogen content 18 mass%) by DIC Corporation is mentioned.

  (B) It is preferable that a component is 0.5-1.5 equivalent with respect to an epoxy group. Adhesiveness with outer layer copper, Tg, and insulation can be made into a favorable state because an epoxy resin hardening | curing agent shall be 0.5-1.5 equivalent with respect to an epoxy group.

  The (C) component polyamide resin, polyamideimide resin, polyethersulfone resin, or crosslinked rubber particles are not particularly limited, but can be uniformly dispersed with the (A) component and the (B) component to form a roughened shape. Is preferred. These may be used alone or in combination of two or more.

  (C) It is preferable that the compounding quantity of a component is 10-40 mass% in the ratio in the total solid of the resin composition except a solvent. 10-40% by mass, while maintaining good heat resistance, suppresses the toughness of the resin and the decrease in elongation, and moreover, it becomes easier to obtain a dense roughened shape, and the adhesive strength with the plated copper is improved. Decline can be prevented.

Among the components (C), the polyamide resin, the polyamideimide resin, and the polyethersulfone resin are preferably dissolved in the epoxy resin composition and the solvent thereof, but may be uniformly dispersed in a fine shape.
As these commercial products, rubber-modified polyamide resin manufactured by Nippon Kayaku Co., Ltd .: BPAM-154, polyamide imide manufactured by Hitachi Chemical Co., Ltd .: HPC-9100, HCP-7200, polyethersulfone resin manufactured by Sumitomo Chemical Co., Ltd. : Sumika Excel 5003P, 4100P, etc.

  Among the components (C), the average primary particle size of the crosslinked rubber particles is preferably 1 μm or less. Materials include acrylonitrile butadiene copolymer, cross-linked NBR particles obtained by copolymerization of acrylonitrile and butadiene, copolymers of acrylonitrile, butadiene and carboxylic acids such as acrylic acid, polybutadiene, NBR, and silicon rubber as cores. So-called core-shell rubber particles having an acrylic acid derivative as a shell can be used.

  For example, as a commercially available product of carboxylic acid-modified acrylonitrile butadiene rubber particles, XER-91 manufactured by Nippon Synthetic Rubber Co., Ltd. can be mentioned, and the core shell particles of butadiene rubber-acrylic resin can be manufactured by Rohm and Haas Electronic Materials Co., Ltd. An example is AC-3832, manufactured by Gantz Kasei Kogyo Co., Ltd.

  Further, fumed silica may be added to the adhesive layer as the component (D). Any fumed silica may be used, but in view of insulation reliability and heat resistance, those having good dispersibility in the epoxy resin are preferable, and the surface is made hydrophobic, for example, manufactured by Nippon Aerosil Co., Ltd. AEROSIL R972 (trade name) and AEROSIL R202 manufactured by the same company can be used. The content is preferably in the range of 3 to 20% by mass in the solid content of the resin composition for the adhesive layer in order to improve the laser processability.

  The blending amount of fumed silica is preferably 3 to 20% by mass in the total solid content of the resin composition excluding the solvent. When the fumed silica content is 3% by mass or more, the laser workability can be prevented from being lowered and the adhesive layer can be prevented from remaining. Moreover, adhesive strength can be made favorable by setting it as 20 mass% or less.

  The resin composition of the adhesive layer in the present invention is obtained by blending the above-described components (A) to (C) and the component (D) added as necessary, and in addition to an ordinary resin composition Various additives such as a curing accelerator, a thixotropic agent, a surfactant, and a coupling agent to be used can be appropriately blended. After sufficiently stirring them, the resin composition can be obtained by standing until there are no bubbles.

As the curing accelerator, various imidazoles and BF ₃ amine complexes which are latent thermosetting agents can be used. Of these, 2-phenylimidazole and 2-ethyl-4-methylimidazole are preferred from the viewpoint of storage stability of the insulating resin composition, handling property of the B-staged (semi-cured) insulating resin composition, and solder heat resistance. The blending amount is preferably 0.2 to 2.0 parts by mass with respect to 100 parts by mass of the component (A). Solder heat resistance can be made sufficient by being 0.2 mass part or more. Moreover, the storage stability of a resin composition and the handleability of a B-stage-shaped resin composition can be made favorable by being 2.0 mass parts or less.

  The resin composition for forming the adhesive layer is preferably mixed in a solvent and diluted or dispersed to form a varnish from the viewpoint of workability. As this solvent, methyl ethyl ketone, xylene, toluene, acetone, ethylene glycol monoethyl ether, cyclohexanone, ethyl ethoxypropionate, N, N-dimethylformamide, N, N-dimethylacetamide and the like can be used. These solvents may be used alone or in a mixed system. The ratio of the solvent to the resin composition may be a ratio applied conventionally, and the amount of use is adjusted in accordance with the equipment for forming the coating film of the resin composition. When the resin composition of the adhesive layer is applied to a carrier film (support) with a comma coater, the amount of solvent used is adjusted so that the solid content of the resin composition excluding the solvent is 10 to 40% by mass in the varnish. It is preferable.

In order to provide the adhesive layer on the copper foil, the varnish produced as described above is applied on the copper foil so as to have a thickness of 1 to 10 μm after drying with a comma coater or the like. When the thickness is 1 to 10 μm, it can sufficiently cope with the thinning of the wiring board that has been required in recent years.
Although drying temperature and drying time are not specifically limited, Considering characteristics such as drying efficiency and adhesive force of the adhesive layer, it is preferable to set the temperature at 100 to 250 ° C. for 1 to 15 minutes.
The copper foil to be used can be a copper foil having a thickness of 10 to 100 μm, and a copper foil that has not been roughened is preferable. By making the thickness of the copper foil 10 μm or more, the handling becomes good. For example, no trouble occurs even in the etching process in the semi-additive construction method. In addition, when the thickness of the copper foil is 100 μm or less, the handleability in the process is improved, the time required for the last etching removal process is shortened, and the cost for the copper foil can be reduced. Further, since the surface of the copper foil is not roughened, for example, circuit formation can be smoothly performed by the semi-additive method of the outermost layer.

(Insulating film)
Insulating film according to the present invention is composed of the adhesive layer A ¹ and the insulating resin layer. In order to obtain the film, it is preferable to first apply the adhesive layer to the carrier film. This two-layer insulating film peels off the carrier film after lamination and cures with a drier, so that it is a polyethylene terephthalate (PET) film or aluminum foil, or a release-treated PET film or aluminum foil rather than a copper foil Is preferably used. Again, the varnish is applied on a carrier film so as to have a thickness of 1 to 10 μm after drying with a comma coater or the like. Although drying temperature and drying time are not specifically limited, Considering characteristics such as drying efficiency and adhesive force of the adhesive layer, it is preferable to set the temperature at 100 to 250 ° C. for 1 to 15 minutes.

  The insulating resin composition for forming the insulating resin layer includes (i) a polyfunctional epoxy resin (hereinafter sometimes referred to as “(i) component”), (ii) an epoxy resin curing agent (hereinafter referred to as “(ii) Component (sometimes referred to as “component”) and (iii) an inorganic filler (hereinafter also referred to as “component (iii)”). Furthermore, it is more preferable to contain (iv) a phosphorus-based flame retardant (hereinafter sometimes referred to as “component (iv)”).

  (I) As a polyfunctional epoxy resin which is a component, the resin same as the above-mentioned (A) component can be mentioned. (I) It is preferable that the compounding quantity of a component is 20-50 mass% in the ratio in the total solid of the insulating resin composition except a solvent. When the blending amount of the component (i) is 20% by mass or more, the solder heat resistance is prevented from being lowered, and when it is 50% by mass or less, the adhesive strength with the circuit conductor can be improved. Moreover, it is preferable to use a liquid epoxy resin in combination because the fluidity of the resin is improved.

Examples of the epoxy resin curing agent that is component (ii) include the same resins as the component (A) described above.
(Ii) It is preferable that a component is 0.5-1.5 equivalent with respect to an epoxy group. When the epoxy resin curing agent is 0.5 equivalent or more with respect to the epoxy group, the adhesiveness with the outer layer copper is made good, and when it is 1.5 equivalent or less, the decrease in Tg and insulation is suppressed. Can do.

  In addition to the curing agent, a reaction accelerator can be used as necessary. The reaction accelerator is the same as the aforementioned “curing accelerator”.

As the inorganic filler as component (iii), for example, those selected from silica, fused silica, talc, alumina, aluminum hydroxide, barium sulfate, calcium hydroxide, aerosil, and calcium carbonate can be used. However, it may be used as a mixture.
Note that aluminum hydroxide and silica are preferably used alone or in combination from the viewpoint of flame retardancy and low thermal expansion. Moreover, it is preferable to set it as 10-70 mass% in the solid content of the whole insulating resin composition except a solvent, and, as for the compounding quantity of (iii) component, it is more preferable to set it as 30-60 mass%. By setting it as 10-70 mass%, the low thermal expansion effect can be improved and fluidity | liquidity and laser workability can be made favorable.

  The phosphorus-based flame retardant as the component (iv) is not particularly limited as long as it is a compound containing phosphorus, but in view of insulation reliability and heat resistance, those having reactivity with an epoxy resin are preferable. For example, HCA-HQ manufactured by Sanko Co., Ltd. or XZ92741 manufactured by Dow Chemical can be used. (Iv) The content of the component is such that the phosphorus content% is in the range of 0.7 to 3% by mass in the solid content of the insulating resin composition excluding the inorganic filler, and good flame retardance is exhibited. It is preferable from the viewpoint of solder heat resistance.

  The insulating resin composition is obtained by blending the above-described components (i) to (iv) and the like, as well as various thixotropic agents, surfactants, coupling agents and the like used in ordinary resin compositions. Additives can be added as appropriate. After sufficiently stirring these, the insulating resin composition can be obtained by standing until the bubbles disappear.

It is preferable from the viewpoint of workability that the insulating resin composition is also mixed or diluted or dispersed in a solvent to form a varnish. The solvent and the amount used thereof are the same as in the case of the adhesive layer resin composition.
When applying the insulating resin composition to a carrier film provided with an adhesive layer in advance with a comma coater, the amount of the solvent used is adjusted so that the solid content of the resin composition excluding the solvent is 30 to 60% by mass in the varnish. It is preferable to adjust.

  The insulating film according to the present invention is used, for example, as a semi-cured film of an insulating resin composition. Therefore, in order to produce an insulating film, for example, a varnish of an insulating resin composition is prepared as described above, and this varnish is applied on a support with an adhesive layer (for example, a carrier film can be cited as a support). And a method of drying. Moreover, when apply | coating a varnish on the support body with an adhesive layer, a comma coater, a bar coater, a kiss coater, a roll coater etc. can be utilized, and it is used suitably by the thickness of an insulating film (an example of the insulating resin material for wiring boards). The coating thickness, drying conditions after coating and the like are appropriately selected according to the purpose of use and are not particularly limited, but it is generally preferred that the solvent used for the varnish is volatilized by 80% by mass or more.

(Manufacturing method of coreless structure multilayer wiring board)
Hereinafter, with reference to FIGS. 1-4, each process which manufactures the coreless structure multilayer wiring board of this invention is demonstrated.

First, as shown in FIG. 1 (a), on the adhesive layer X ¹ copper foil film 10 adhesive layer X ¹ is formed on the peelable copper foil 12 on the adhesive layer A ¹ and the insulating resin layer 22 The insulating resin layer 22 of the insulating film 20 made of is bonded using a laminator or the like. Incidentally, on the adhesive layer A ¹ of the insulating film 20, it is preferable to the carrier film 24 is provided in consideration of handling properties.

As shown in FIG.1 (b), after peeling the carrier film 24, it hardens | cures in a dryer and laminates | stacks (lamination process). The curing temperature at this time is a temperature and time considering the subsequent plating process, copper annealing process, and the like. In other words, if the curing is advanced too much, the adhesion with copper will be reduced during the subsequent plating process, or on the other hand, if the curing is not sufficient, a phenomenon may occur in which it is eroded by the alkaline treatment solution during the plating treatment and dissolved in the plating solution. To do. Considering these things, it is preferable to perform a curing treatment by applying a heat treatment at 150 to 190 ° C. for 30 to 90 minutes.
Note that heat curing may be performed while applying pressure. In this case, the pressure lamination condition is usually preferably 0.5 to 20 MPa.

Next, to form an adhesive layer A ¹ on the Figure 1 circuit 26 as shown in (c) (circuit layer) by a semi-additive method as described below (the circuit forming step).
When forming a circuit, it is preferable to ^first roughen the adhesive layer A1. As the roughening liquid, an oxidizing roughening liquid such as a chromium / sulfuric acid roughening liquid, an alkaline permanganic acid roughening liquid, a sodium fluoride / chromium / sulfuric acid roughening liquid, or a borofluoric acid roughening liquid can be used. As the roughening treatment, for example, an aqueous solution of diethylene glycol monobutyl ether and NaOH is first heated as a swelling solution to 70 ° C. and immersed for 5 minutes. Next, as a roughening liquid, an aqueous solution of KMnO ₄ and NaOH is heated to 80 ° C. and immersed for 10 minutes. Subsequently, it is neutralized by immersing it in a neutralizing solution, for example, an aqueous hydrochloric acid solution of stannous chloride (SnCl ₂ ) at room temperature for 5 minutes.

After the roughening treatment, a plating catalyst applying treatment for attaching palladium is performed. The plating catalyst treatment is performed by immersing in a palladium chloride plating catalyst solution. Next, an electroless plating layer (conductor layer) having a thickness of 0.3 to 1.5 μm on the entire surface of the adhesive layer A ¹ by immersion in an electroless plating solution (including the inner surface of the via hole when a via hole is formed) To precipitate. If necessary, further electroplating is performed to obtain a necessary thickness. The electroless plating solution used for electroless plating can be a known electroless plating solution and is not particularly limited. Also, electroplating can be performed by a known method and is not particularly limited. These platings are preferably copper platings.

  After forming the electroless plating layer, a circuit layer 26 is formed by forming a resist layer, exposing to a predetermined pattern and performing etching. Known conditions can be employed for resist, exposure, etching, and the like.

As shown in FIG. 2A, the insulating resin layer 22 of the insulating film 20 composed of the adhesive layer A ² and the insulating resin layer 22 is bonded onto the adhesive layer A ¹ on which the circuit is formed. And as shown in FIG.2 (b), it hardens | cures and laminates | stacks (lamination process). The bonding and curing process are the same as described above.

Next, as shown in FIG. 2C, a via hole H is formed at a predetermined position of the adhesive layer A ^{2 by} a known method (for example, laser processing) (via hole forming step). After forming the via hole H, as shown in FIG. 2 (d), to form a circuit 26 (circuit layer) on the adhesive layer A ² by a semi-additive method (circuit forming step).

Thereafter, the desired number of layers may be obtained by sequentially performing the steps as shown in FIGS. For example, when another circuit layer is formed on the adhesive layer A ² having the circuit 26, the adhesive layer A ² is formed on the adhesive layer A ² on which the circuit is formed as shown in FIG. ^The insulating resin layer 22 of the insulating film 20 composed of ³ and the insulating resin layer 22 is bonded. And as shown in FIG.3 (b), it hardens | cures and laminates | stacks (lamination process).

After the lamination step shown in FIG. 3, the copper foil 12 of the copper foil film 10 is peeled off as shown in FIG. 4 (a) (copper foil peeling step). Then, a via hole H in a predetermined position of the adhesive layer X ¹ after copper foil peeling, as shown in FIG. 4 (b) (via hole forming step). A via hole H is also formed at a predetermined position of the adhesive layer A ³ (via hole forming step).

After forming the via hole H, a circuit is formed on the adhesive layer X ¹ and the adhesive layer A ³ by a semi-additive method (circuit formation process). In this way, the coreless structure multilayer wiring board of the present invention is manufactured.

Incidentally, on the adhesive layer X ¹ which circuits are formed, the adhesive layer A ² and bonded to the insulating resin layer of an insulating film made of an insulating resin layer, and a laminating step of laminating by subjecting to a curing treatment, the adhesive layer A ² By further providing a series of steps sequentially including a via hole forming step for forming a via hole H at a predetermined position and a circuit forming step for forming a circuit on the adhesive layer A ² by a semi-additive method, Can be a desired number of layers.
Further, in the semi-additive method after forming the via hole H, both sides may be plated or exposed simultaneously, or one side is plated and / or exposed and then the other side is plated and / or exposed. You may expose.

The coreless structure multilayer wiring board of the present invention manufactured as described above has high adhesion to the metal layer forming the circuit without depending on the anchor effect as in the prior art. For example, even if the surface roughness Ra of the adhesive layer after removing a part of the circuit formed on at least one surface by etching is 0.3 μm or less, the adhesiveness to the metal layer is It is kept good.
Moreover, by having a plurality of adhesive layers, the adhesive layers function as a stress relaxation layer, and the occurrence of warpage is suppressed.

EXAMPLES Next, although an Example demonstrates this invention, this invention is not limited to these Examples.
Example 1
(1) Adhesive layer composition:
100 parts by mass of a polyfunctional epoxy resin (NC-3000H: trade name, manufactured by Nippon Kayaku Co., Ltd.), 20 parts by mass of an epoxy resin curing agent (LA-1356: trade name, manufactured by DIC Corporation, solid content 50% by mass), Curing accelerator (2-phenylimidazole, manufactured by Shikoku Chemicals Co., Ltd.) 0.2 parts by mass, crosslinked rubber particles (Paraloid EXL-2655: trade name, manufactured by Rohm and Haas Electronic Materials Co., Ltd.) 15 parts by mass, fumed silica ( R-972: trade name, manufactured by Nippon Aerosil Co., Ltd.) 15 parts by mass, solvent (2-butanone) 250 parts by mass, cyclohexanone 200 parts by mass are mixed with a stir bar, and a disperser (Nanomizer, trade name, Yoshida Kikai Kogyo Co., Ltd.) Varnish A was obtained.

(2) Production of copper foil film and PET film with adhesive layer:
The varnish A was applied to a glossy surface of copper foil (YGP-35: trade name, manufactured by Nippon Electrolytic Co., Ltd., thickness: 35 μm) so that the thickness after drying was 8 μm, and dried at 140 ° C. for 10 minutes. A copper foil film was obtained.

(3) Insulating resin composition:
100 parts by mass of a polyfunctional epoxy resin (NC-3000H: trade name, manufactured by Nippon Kayaku Co., Ltd.), 40 parts by mass of an epoxy resin curing agent (LA-3018: trade name, manufactured by DIC Corporation, solid content 50% by mass), Phosphorus flame retardant (HCA-HQ: trade name, manufactured by Sanko Co., Ltd.) 40 parts by mass, inorganic filler (spherical silica) (SO-C2: trade name, manufactured by Admatex Co., Ltd.) 100 parts by mass, curing accelerator (2 -Ethyl-4-methylimidazole (manufactured by Shikoku Kasei Kogyo Co., Ltd.) 0.5 parts by mass and 150 parts by mass of solvent (2-butanone) were mixed uniformly, and a disperser (Nanomizer, trade name, manufactured by Yoshida Kikai Kogyo Co., Ltd.) Was used to obtain uniform varnish B.

(4) Production of insulating resin film:
In order to obtain an insulating film having a two-layer structure, first, the varnish A is dried on a release-treated surface of a release-treated polyethylene terephthalate (PET) film (PET-38X, trade name, manufactured by Lintec Corporation). Was applied to a thickness of 5 μm and dried at 140 ° C. for 10 minutes to obtain a PET film with an adhesive layer.
Next, the varnish B was applied to the adhesive layer side of the PET film with an adhesive layer so that the thickness after drying was 35 μm, and dried at 100 ° C. for 5 minutes to obtain an insulating resin film.

(5) Fabrication of coreless structure multilayer wiring board:
Batch type vacuum pressure laminator MVLP-500 (trade name, manufactured by Meiki Seisakusho Co., Ltd.) with the copper foil film and the insulating resin film facing the surface of the insulating resin layer in contact with the adhesive layer of the copper foil film. And bonded together. Next, after peeling off the PET film, the insulating resin layer is cured under a curing condition at 180 ° C. for 60 minutes to form a substrate having a structure of copper foil-first adhesive layer-first insulating resin layer-second adhesive layer. Obtained.

In order to chemically roughen the second adhesive layer, an aqueous solution of diethylene glycol monobutyl ether: 200 ml / L, NaOH: 5 g / L was prepared as a swelling liquid, heated to 80 ° C. and immersed for 3 minutes. Next, an aqueous solution of KMnO ₄ : 60 g / L and NaOH: 40 g / L was prepared as a roughening solution, heated to 80 ° C. and immersed for 5 minutes. Subsequently, it was neutralized by immersing it in an aqueous solution of a neutralizing solution (SnCl ₂ : 30 g / L, HCl: 300 ml / L) at room temperature (25 ° C.) for 5 minutes.

In order to form the second circuit layer on the surface of the second adhesive layer, first, an electroless plating catalyst solution containing PdCl ₂ (HS-202B: trade name, manufactured by Hitachi Chemical Co., Ltd.) is added to room temperature (25 ° C. ) -10 minutes immersion treatment, water washing, and immersion for 15 minutes at room temperature in a plating solution (CUST-201: trade name, manufactured by Hitachi Chemical Co., Ltd.) for electroless copper plating to give electroless plating . Furthermore, a 15 μm thick plating resist (RD-1215: trade name, manufactured by Hitachi Chemical Co., Ltd.) is laminated, exposed using a negative mask and a light source of 405 nm under the condition of 120 mJ / cm ² , and 1% aqueous sodium carbonate solution Was developed, and plated with a thickness of 8 μm by copper sulfate electrolytic plating.

  After that, the resist is stripped using 3% aqueous sodium hydroxide solution, unnecessary power feeding layer (electroless plating layer) is etched away using sulfuric acid-hydrogen peroxide aqueous solution, and unnecessary using the above permanganic acid roughening solution. Palladium was removed to form the second circuit layer. Furthermore, in order to make a multilayer, the surface of the second circuit conductor was immersed in an aqueous solution of sodium chlorite: 50 g / l, NaOH: 20 g / l, trisodium phosphate: 10 g / l at 85 ° C. for 20 minutes, and washed with water. Then, it was dried at 80 ° C. for 20 minutes to form copper oxide irregularities on the surface of the second circuit conductor.

(5) Step (4) is repeated twice to obtain a copper foil, a first adhesive layer, a first insulating resin layer, a second adhesive layer, a second circuit layer, a second insulating resin layer, and a third adhesive layer. A substrate having a structure of third circuit layer-third insulating resin layer-fourth adhesive layer was obtained.

After curing at 180 ° C., the copper foil was removed by etching, and then via holes for interlayer connection were formed in the first adhesive layer-first insulating resin layer and the third insulating resin layer-fourth adhesive layer. Using a CO ₂ laser processing machine (LCO-1B21 type) manufactured by Mechanics, processing was performed under conditions of a beam diameter of 60 μm, a frequency of 500 Hz, a pulse width of 5 μsec, and a shot number of 4. Thereafter, a four-layer coreless structure multilayer wiring board was obtained through chemical roughening, electroless plating, resist preparation, electroplating, peeling, and soft etching.

(Example 2)
In the adhesive layer of Example 1, 20 parts by mass of Kayaflex BPAM-155 manufactured by Nippon Kayaku Co., Ltd. was used instead of Paraloid EXL2655 of the crosslinked organic rubber particles, and the thickness of the adhesive layer was 5 μm. Thus, a four-layer coreless structure multilayer wiring board was obtained.

(Example 3)
In the adhesive layer of Example 1, instead of the paraloid EXL2655 of the crosslinked organic rubber particles, HPC-5010S (solid content 30% by mass) manufactured by Hitachi Chemical Co., Ltd. was 60 parts by mass, and the thickness of the adhesive layer was 4 μm, In the same manner as in Example 1, a four-layer coreless structure multilayer wiring board was obtained.

(Comparative Example 1)
In Example 1, a four-layer coreless structure multilayer wiring board was obtained in the same manner as in Example 1 except that the adhesive layer was not formed.

  About the coreless structure multilayer wiring board produced as described above, the adhesion strength with the outer layer circuit, the surface roughness of the surface, and the warpage at a size of 40 × 40 mm were measured as follows. The results are shown in Table 1 below.

[Adhesion strength with outer layer circuit]
A part having a width of 5 mm and a length of 100 mm is formed by etching copper on a part of the L1 circuit layer (third circuit layer) of the coreless structure multilayer wiring board obtained in each of the examples and comparative examples. It was peeled off at the layer / resin interface, grabbed with a gripper, and the load when peeled off at room temperature at a pulling speed of about 50 mm / min in the vertical direction was measured. The results are shown in Table 1 below.

[Insulation layer surface roughness]
A part of copper of the L1 circuit layer (third circuit layer) of the coreless structure multilayer wiring board obtained in each example and comparative example is etched, and the exposed insulating layer (adhesion auxiliary layer) surface is Ryoka Systems Co., Ltd. The surface roughness Ra was measured using a micromap MN5000 model manufactured by the manufacturer. The results are shown in Table 1 below. The etching conditions were as follows.

[Warpage measurement]
The coreless structure multilayer wiring board produced in each example and comparative example was cut into a size of 40 mm × 40 mm, and the amount of warpage was measured using a laser three-dimensional measuring instrument. The results are shown in Table 1 below.

  As is clear from Table 1, the coreless structure multilayer wiring board of each example showed an electroless copper plating and a high adhesive force on a smooth resin surface, and showed a good result with a low warpage. On the other hand, the coreless structure multilayer wiring board of Comparative Example 1 had a large surface roughness and a large amount of warpage.

10 ... copper film 12 ... copper foil 20 ... insulating film 22 ... insulating resin layer 24 ... carrier film 26 ... circuit ^{A 1, A 2, A 3} ··· adhesive layer X ¹ ... adhesive layer H ... via hole

Claims (7)

Bonding the insulating resin layer of the insulating film composed of the adhesive layer A ¹ and the insulating resin layer on the adhesive layer X ¹ of the copper foil film in which the adhesive layer X ¹ is formed on the peelable copper foil, A manufacturing method of a coreless structure multilayer wiring board including a laminating step of laminating these films by performing a curing process, and including the following steps (1) and (2) after the laminating step.
(1) Circuit forming step for forming a circuit on the adhesive layer A ¹ by a semi-additive method (2) Copper foil peeling step for peeling the copper foil of the copper foil film, and predetermined adhesive layer X ¹ after peeling the copper foil A via hole forming step for forming a via hole at a position, and a circuit forming step for forming a circuit on the adhesive layer X ¹ by a semi-additive method after forming the via hole On the adhesive layer A ¹ on which the circuit after the circuit forming step (1) is formed,
(A) a laminating step in which the insulating resin layer of the insulating film composed of the adhesive layer A ² and the insulating resin layer is bonded, and subjected to a curing treatment to be laminated;
(B) a via hole forming step of forming a via hole at a predetermined position of the adhesive layer A ² ;
(C) a circuit forming step of forming a circuit on the adhesive layer A ² by a semi-additive method;
The method of manufacturing a coreless structure multilayer wiring board according to claim 1, wherein the steps (A) to (C) are sequentially included at least once. On the adhesive layer X ¹ on which the circuit after the circuit forming step (2) is formed,
(A) a laminating step in which the insulating resin layer of the insulating film composed of the adhesive layer A ² and the insulating resin layer is bonded, and subjected to a curing treatment to be laminated;
(B) a via hole forming step of forming a via hole at a predetermined position of the adhesive layer A ² ;
(C) a circuit forming step of forming a circuit on the adhesive layer A ² by a semi-additive method;
The manufacturing method of the coreless structure multilayer wiring board of Claim 1 or 2 which passes through the process of said (A)-(C) containing 1 sequentially at least once. The adhesive layers X ¹ and A ¹ are each composed of (A) an epoxy resin, (B) an epoxy resin curing agent, (C) a polyamide resin, a polyamideimide resin, a polyethersulfone resin, or crosslinked rubber particles. 2. A method for producing a coreless structure multilayer wiring board according to 1. The adhesive layer A ² is composed of (A) an epoxy resin, (B) an epoxy resin curing agent, (C) a polyamide resin, a polyamideimide resin, a polyethersulfone resin, or crosslinked rubber particles. A method for producing a coreless structure multilayer wiring board according to claim 1.   The coreless structure multilayer wiring board manufactured by the manufacturing method of the coreless structure multilayer wiring board of any one of Claims 1-5.   7. The coreless structure multilayer wiring board according to claim 6, wherein the surface roughness Ra of the adhesive layer after removing a part of the circuit formed on at least one surface by etching is 0.3 [mu] m or less.

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