JP2007049106A - Planarized resin-coated printed wiring board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a planarized resin-coated printed wiring board without the need of polishing, both surfaces of which have been extremely highly planarized, the thickness of which is constant all over the printed wiring board, and which is excellent in the mounting stability and impedance characteristic of parts; and a multilayer printed wiring board useful as an internal layer that is manufactured by such a printed wiring board and both surfaces of which have been extremely highly planarized. <P>SOLUTION: The method for manufacturing a printed wiring board, in which a photo/thermal hardening resin composite is applied to one of the surfaces of a printed wiring board having a through-hole and the through-hole. After the following steps (1) and (2) are carried out sequentially; the photo/thermal hardening resin composite is applied to the other surface of the printed wiring board, and the following steps (1) to (3) are carried out sequentially for planarizing the surface to which resin is applied (step 1), for photo-hardening the resin to be applied (step 2), and for thermal-hardening the photo hardening resin (step 3). <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a printed wiring board and a manufacturing method thereof. In particular, the present invention is a printed wiring board whose surfaces (front and back surfaces) are highly flattened, and is a flattened resin-coated printed wiring board coated with a resin (particularly the entire surface). The present invention relates to a wiring board, a double-sided printed wiring board useful as an outer layer, and a manufacturing method thereof.

  Conventionally, as a method for producing a flattened hole-filled printed wiring board, first, through holes of the printed wiring board are filled and filled with a thermosetting resin composition, and then the filled resin is thermally cured, and then the surface of the printed wiring board There is known a method of flattening the surface by removing the cured resin portion raised from the surface by polishing (Patent Document 1).

  However, this method has problems that the number of manufacturing steps is increased and the polishing cost is increased. In addition, there is a problem that deformation (dimensional change) of the printed wiring board occurs due to polishing.

  Therefore, there is a demand for a method for flattening the surface of the printed wiring board without polishing. As such a method, the method of Patent Document 2 has been proposed. That is, first, the through hole of the printed wiring board is filled and filled with a curable resin [FIG. 7A, 705]. Next, the printed wiring board is sandwiched between curable resists [FIG. 7B, 727] and is crimped by hot pressing. Thereafter, the filling resin and the curable resist are completely cured by high-temperature heating [FIGS. 7C and 728].

  However, with this method, it is difficult to completely adhere the resist [FIG. 7B, 727] to the recesses [FIG. 7B, 704a] between the circuits even in the case of vacuum pressing, especially in the dense circuit area. As a result, a slight gap is generated between the recess and the resist film, and air may remain in the gap. For this reason, the so-called “popcorn phenomenon” in which the residual air is thermally expanded and the resist film surface is expanded during subsequent high-temperature heating may occur [FIGS. 7C and 725].

  On the contrary, in the circuit depopulated portion, since a large amount of the resist resin for coating [FIGS. 7B, 727] is used for filling the recesses between the circuits [FIG. 7B, 704b], a slight depression is formed on the resist surface after heat curing. May occur [FIG. 7C, 726].

  Therefore, the printed wiring board manufactured by such a method has swelling and depressions on the surface and is not sufficiently flattened. ) Becomes lower.

  Furthermore, when the surface of the printed wiring board has swelling and depressions, the thickness of the insulating layer, in particular, the thickness of the insulating layer on the conductive circuit layer [FIG. 7C, 702] is not stable, and impedance characteristics such as increased fluctuation in impedance, etc. Bring about a decline.

  That is, in the bulging peripheral edge [FIG. 7C, 729], the thickness [FIG. 8A, 831] of the insulating layer on the conductive circuit layer [FIG. 8A, 802] gradually increases toward the bulging center. On the other hand, in the peripheral portion of the recess “FIGS. 7C and 730”, the thickness [FIGS. 8B and 831] of the insulating layer on the conductive circuit layer [FIGS. 8B and 802] gradually decreases toward the center of the recess.

  Moreover, even in a multilayer printed wiring board manufactured by using such a printed wiring board that is not sufficiently flattened as an outer layer or an inner layer, the component mounting stability (bump bondability, etc.) and the impedance characteristics are degraded. Come on.

Japanese Patent Laid-Open No. 2001-15909. JP 2001-111214 A.

  In view of the above circumstances, according to the present invention, both surfaces of the printed wiring board are extremely flattened, and the thickness of the printed wiring board is constant over the entire area of the printed wiring board (that is, every portion / part). As a result, it is possible to produce a flattened resin-coated printed wiring board that is excellent in component mounting stability (bump bondability, etc.) and impedance characteristics (impedance stability, etc.) without requiring polishing. , With purpose. Furthermore, the present invention is a printed wiring board manufactured from such a printed wiring board, and both surfaces are extremely highly flattened, and is a multilayer printed wiring board useful as an inner layer (particularly a four-layer printed wiring board), An object of the present invention is to provide a printed wiring board (particularly a double-sided printed wiring board) useful as an outer layer.

  In order to solve the above-mentioned problems, the present inventors have intensively studied, and as a result, have reached the following present invention.

That is, in the first invention of the present application, after applying the photo / thermosetting resin composition to one surface of the printed wiring board having a through hole and the through hole, and sequentially performing the following steps 1) and 2), Provided is a method for producing a printed wiring board, in which a photo / thermosetting resin composition is applied to the other surface of the printed wiring board, and the following steps 1) to 3) are sequentially performed.
1) The process of planarizing the coating resin surface.
2) A step of photocuring the coating resin.
3) A step of thermosetting the photocurable resin.

In the second invention of the present application, a light / thermosetting resin composition is applied to one surface and a through hole of a printed wiring board having a through hole, and the above steps 1) and 2) are sequentially performed, and then light / heat is applied. After applying the curable resin composition to the other surface of the printed wiring board and sequentially performing the above steps 1) and 2),
A) Perform step 3) above, and then press the printed wiring board between the pressure-bonding materials to laminate and press the pressure-bonding material, or B) sandwich the printed wiring board between the pressure-bonding materials and raise the temperature to be equal to or higher than the thermosetting temperature of the photocurable resin. And press and laminate the pressure bonding material and the above step 3) at the same time,
Provided is a method for producing a multilayer printed wiring board in which a micro via is formed by drilling from the surface of a pressure-bonding material to a conductor layer, whole surface plating is performed, a circuit is formed from the plating layer, and then a resist is coated.

  A third invention of the present application provides a method for producing a multilayer printed wiring board according to the second invention of the present application, in which a resist has an opening.

  In the fourth invention of the present application, a light / thermosetting resin composition is applied to one surface and a through hole of a printed wiring board having a through hole, and the above steps 1) and 2) are sequentially performed. A curable resin composition is applied to the other surface of a printed wiring board, and after the above steps 1) to 3) are sequentially performed, a method for producing a printed wiring board in which an opening is provided in a coating resin layer is provided.

  A fifth invention of the present application provides a method for manufacturing a printed wiring board according to the third or fourth invention of the present invention, wherein the surface exposed by the opening is coated by plating.

  A sixth invention of the present application provides a method for manufacturing a printed wiring board according to the first to fifth inventions of the present invention, wherein the conductive layer surface of the printed wiring board having a through hole is roughened.

  A seventh invention of the present application provides a printed wiring board manufactured by the manufacturing method according to any one of the first to sixth inventions of the present application.

  According to the present invention, the surface of the printed wiring board is extremely flattened, and the thickness of the printed wiring board is constant over the entire area of the printed wiring board (that is, every portion / part). A flattened resin-coated printed wiring board excellent in component mounting stability (bump bondability and the like) and impedance characteristics (impedance stability and the like) can be manufactured without requiring polishing. Further, according to the present invention, a printed wiring board manufactured from such a printed wiring board and having both surfaces extremely flattened, which is useful as an inner layer, particularly a multilayer (particularly four layers) printed wiring board, and an outer layer Useful (especially double-sided) printed wiring boards can be provided.

  In the method for producing a flattened resin-coated printed wiring board of the present invention, a light / thermosetting resin composition (that is, a two-stage curable resin in which first-stage curing is performed by light irradiation and second-stage curing is performed by heating) Examples of the composition) include those containing the following components [I] to [V].

[I]: Unsaturated fatty acid partial adduct of epoxy resin.
[II]: (Meth) acrylates.
[III]: Photocrosslinking agent.
[IV]: Epoxy resin.
[V]: Latent curing agent.

  Preferably, specific examples of the photo / thermosetting resin composition include those described in JP2003-105061A and JP2004-75967A.

  The light / thermosetting resin composition contains an unsaturated fatty acid partial adduct of epoxy resin as component [I]. The epoxy value of the epoxy resin that is the raw material for preparing the component [I] (hereinafter sometimes simply referred to as “raw material epoxy resin”) is, for example, preferably 130 to 400, particularly 150 to 250. Examples of the epoxy resin for raw materials include phenol novolac type epoxy resins, epoxy resins from polyfunctional phenols, naphthalene skeleton epoxy resins, glycidyl amine epoxy resins, triazine skeleton epoxy resins, glycidyl ester epoxy resins, and alicyclic types. An epoxy resin etc. are mentioned.

  Preferably, as the raw material epoxy resin, each compound represented by the formulas [Chemical I-E1] to [Chemical I-E7] shown in Table 1, particularly phenol novolac type epoxy resin, cresol novolac type epoxy resin, trisphenyl A methane type epoxy resin, a bisphenol A novolak type epoxy resin, a dicyclopentadiene phenol type epoxy resin, etc. are mentioned, and one or more of these may be used.

  Throughout this application, where G is a glycidyl group, i.e. the following formula, unless explicitly used otherwise:

を表す。

Represents.

In the formulas [Chemical I-E1] to [Chemical I-E3], n represents an integer of 0 to 30. In the formulas [Chemical I-E4] to [Chemical I-E6], n represents an integer of 1 to 30. In the formula [Chemical I-E7], n represents an integer of 2 to 50. In the formula [Chemical I-E2], R ¹ and R ² each independently represent H or CH ₃ .

  As an unsaturated fatty acid which is the other preparation raw material of component [I], for example, the following formula [Chemical Formula I-UFA],

［式中、Ｒ^１〜Ｒ^３は、それぞれ独立に、Ｈ又はＣＨ_３を表す。］
で表されるものが挙げられる。具体的には不飽和脂肪酸としては、アクリル酸、メタクリル酸、クロトン酸等が挙げられる。

[Wherein, R ^{1 to} R ³ each independently represent H or CH ₃ . ]
The thing represented by is mentioned. Specific examples of the unsaturated fatty acid include acrylic acid, methacrylic acid, and crotonic acid.

  Component [I] may be prepared by a conventional preparation method. For example, one or more types of raw material epoxy resins and one or more types of unsaturated fatty acids [for example, acrylic acid and / or methacrylic acid (hereinafter sometimes simply referred to as “(meth) acrylic acid”)] are used as necessary. It may be prepared by stirring and mixing under heating.

  Component [I] is a product obtained by partially adding an unsaturated fatty acid to an epoxy resin. That is, in the unsaturated fatty acid partial adduct of the epoxy resin, at least one epoxy group remains in the epoxy resin after the addition of the unsaturated fatty acid. Specifically, the unsaturated fatty acid is preferably added to 20 to 80%, particularly 40 to 60% of the epoxy group in the raw material epoxy resin. Those having an addition amount of unsaturated fatty acid of less than 20% (simply referred to as “less than 20% unsaturated fatty acid adduct”, hereinafter the same shall apply) As a result, the first-stage photocured product may adhere to the cover film when the cover film described later is peeled off. On the other hand, an 80% excess unsaturated fatty acid adduct may deteriorate the toughness of the cured product due to a decrease in the epoxy group, and may easily generate cracks.

  Examples of component [I] include adducts of novolac type epoxy resin and (meth) acrylic acid (specifically, adducts of cresol novolac type epoxy resin and acrylic acid, etc.). The above may be contained in the light / thermosetting resin composition.

  Preferably, as the component [I], an acrylic acid partial adduct of a phenol novolac type epoxy resin, an acrylic acid partial adduct of a cresol novolac type epoxy resin, an acrylic acid partial adduct of a trisphenylmethane type epoxy resin, or a bisphenol A novolak Methacrylic acid partial adduct of type epoxy resin, methacrylic acid partial adduct of dicyclopentadiene phenol type epoxy resin, crotonic acid partial adduct of phenol novolac type epoxy resin and the like, and one or more of these may be used.

  The photo / thermosetting resin composition contains (meth) acrylates (that is, acrylates and / or methacrylates) as component [II]. In the component [II], examples of the acrylate include esterified products of acrylic acid and a hydroxy compound. Examples of the methacrylates include esterified products of methacrylic acids and hydroxy compounds.

  Examples of the acrylic acids and methacrylic acids include unsaturated fatty acids represented by the above formula [Chemical I-UFA]. Specific examples of acrylic acids and methacrylic acids include acrylic acid, methacrylic acid, and crotonic acid.

  Examples of the hydroxy compound include alcohols, (hemi) acetals or (hemi) ketals, and hydroxy acid esters. Examples of alcohols include lower alcohols, ring alcohols, polyhydric alcohols, and aromatic alcohols. In the hydroxy compound, examples of (hemi) acetal or (hemi) ketal include condensates of the above alcohols (for example, ring alcohols, polyhydric alcohols, etc.) with formaldehyde and hydroxyaldehyde. In the hydroxy compound, specific examples of the hydroxy acid ester include caprolactone ring-opening adduct of furfuryl alcohol, neopentyl glycol hydroxypivalate, and the like.

  Preferably, as the component [II], each compound represented by the formulas [Chemical Formula II-1] to [Chemical Formula II-9] shown in Table 2, particularly isobornyl acrylate, dicyclopentanyl methacrylate, hydroxybivalin. Examples include acid neopentyl glycol diacrylate, tricyclodecane dimethanol acrylate, trimethylolpropane triacrylate, dipentaerythritol hexaacrylate, isobornyl crotonic acid, and the like, and one or more of these may be contained.

  The photo / thermosetting resin composition contains a photocrosslinking agent as component [III]. Examples of component [III] include those that initiate the first-stage curing reaction by irradiation with light, for example, ultraviolet rays having a wavelength of 200 to 400 nm.

  Specifically, the component [III] includes hydroxy ketones, benzyl methyl ketals, acylphosphine oxides, amino ketones, benzoin ethers, benzoyl compounds, thioxanthones, biimidazoles, dimethylaminobenzoic acid esters. , Sulfonium salts, anthraquinones, acridones, acridines, carbazoles, titanium complexes, and one or more of these.

  Preferably, examples of component [III] include the compounds represented by the formulas [Chemical Formula III-1] and [Chemical Formula III-2] shown in Table 3, and may contain one or more of these compounds.

  The photo / thermosetting resin composition contains an epoxy resin as component [IV]. Examples of the epoxy resin include a crystalline epoxy resin and / or a liquid epoxy resin. In the component [IV], the crystalline epoxy resin is preferably, for example, 80 to 110 ° C, particularly 90 to 105 ° C. Furthermore, as a crystalline epoxy resin, the viscosity (mPa · s) is preferably 50 or less, particularly 0.1 to 20 in the melting point to the melting point + 20 (° C.). Further, as the crystalline epoxy resin, those which are hardly soluble in the photo / thermosetting resin composition are preferable.

  Examples of the crystalline epoxy resin include crystalline epoxy resins such as biphenyl type, diphenyl type, hydroquinone type, biphenyl novolac type, and fluorin type, and one or more of these may be contained.

  Examples of the biphenyl type crystalline epoxy resin include the following formula [Chemical IVc-1],

［式中、ＲはＨ若しくはＣＨ_３を表す。］
で表されるものが挙げられ、これらの一種以上含有してよい。

[Wherein R represents H or CH ₃ . ]
These may be included, and one or more of these may be contained.

  As the diphenyl type crystalline epoxy resin, for example, the following formula [Formula IVc-2],

［式中、ＸはＯ若しくはＳを表し、並びにＲ^１及びＲ^２は、それぞれ独立に、Ｈ、ＣＨ_３若しくはｔ−ブチルを表す。］
で表されるものが挙げられ、これらの一種以上含有してよい。

[Wherein, X represents O or S, and R ¹ and R ² each independently represent H, CH ₃ or t-butyl. ]
These may be included, and one or more of these may be contained.

  Examples of the hydroquinone type crystalline epoxy resin include the following formula [Formula IVc-3],

［式中、ｎは０、１若しくは２を表す。］
で表されるものが挙げられ、これらの一種以上含有してよい。

[Wherein n represents 0, 1 or 2. ]
These may be included, and one or more of these may be contained.

  Examples of the biphenyl novolac type crystalline epoxy resin include the following formula [Chemical IVc-4],

［式中、ｎは１若しくは２を表す。］
で表されるものが挙げられ、これらの一種以上含有してよい。

[Wherein n represents 1 or 2. ]
These may be included, and one or more of these may be contained.

  As the fluorescein type crystalline epoxy resin, for example, the following formula [Formula IVc-5],

で表されるものが挙げられる。

The thing represented by is mentioned.

  Preferably, examples of the crystalline epoxy resin include tetramethylbiphenyl type epoxy resin, hydroquinone diglycidyl ether, di- (p-glycidylphenyl) ether, and the like.

  In component [IV], the liquid epoxy resin refers to an epoxy resin that is in a liquid or semi-solid state at room temperature, and examples thereof include an epoxy resin having fluidity at room temperature. As such a liquid epoxy resin, for example, the viscosity (room temperature, mPa · s) is 20000 or less, particularly preferably 1000 to 10,000.

  Specifically, as the liquid epoxy resin, the following formula [Formula IVl-1],

［式中、ｎは０若しくは１を表す。］
で表されるビスフェノールＡ型エポキシ樹脂が挙げられ、これらの一種以上含有してよい。

[Wherein n represents 0 or 1; ]
The bisphenol A type epoxy resin represented by these is mentioned, You may contain these 1 or more types.

  Furthermore, as a specific example of the liquid epoxy resin, the following formula [Formula IVl-2],

［式中、ｎは０若しくは１を表す。］
で表されるビスフェノールＦ型エポキシ樹脂が挙げられ、これらの一種以上含有してよい。

[Wherein n represents 0 or 1; ]
The bisphenol F type epoxy resin represented by these is mentioned, You may contain these 1 or more types.

  Further, specific examples of the liquid epoxy resin include naphthalene type, diphenylthioether (sulfide) type, trityl type, alicyclic type, those prepared from the following alcohols, diallylbis A type , Methylresorcinol type, bisphenol AD type, N, N, O-tris (glycidyl) -p-aminophenol and the like, and one or more of these may be contained.

  Preferably, the liquid epoxy resin includes bisphenol A type epoxy resin, bisphenol F type epoxy resin, N, N, O-tris (glycidyl) -p-aminophenol, bisphenol AD type epoxy resin, etc. You may contain more than a seed.

  The light / thermosetting resin composition contains a latent curing agent as component [V]. Component [V] causes a second-stage curing reaction by heating. As the component [V], for example, those having a second-stage curing reaction start temperature of 150 to 300 ° C., particularly 150 to 200 ° C. are preferable.

Specifically, as component [V], dicyandiamide (DICY), imidazole, BF ₃ -amine complex, amine adduct type curing agent, amine-acid anhydride (polyamide) adduct type curing agent, hydrazide type curing agent And carboxylic acid salts and onium salts of amine-based curing agents, and one or more of these may be contained.

  Specifically, in the component [V], as the amine adduct type curing agent, an imidazole-based curing agent [2-ethyl-4-methylimidazole, 2-methylimidazole, 2,4-diamino-6- (2′- Methylimidazolyl- (1H))-ethyl-S-triazine and the like] or an adduct of an amine-based curing agent (such as diethylamine) and an epoxy compound, urea or an isocyanate compound. Examples of the hydrazide curing agent include adipic acid dihydrazide (ADH), sebacic acid dihydrazide (SDH), and the like. Examples of carboxylates of amine curing agents include nylon salts and ATU (3,9-bis (3-aminopropyl) -2,4,8,10-tetraoxaspiro [5,5] undecane) / adipic acid Examples include salts. Examples of onium salts include sulfonium salts, ammonium salts, and phosphonium salts.

  Preferably, examples of component [V] include the compounds represented by the formulas [Chemical V-1] to [Chemical V-3] shown in Table 4, and one or more of these may be contained.

  Various additives may be added to the light / thermosetting resin composition as necessary. Examples of the additive include a filler, an organic / inorganic colorant, a flame retardant, an antifoaming agent, and the like.

  In the composition of the photo / thermosetting resin composition, the component [II] is 100 to 300 parts by weight (particularly 150 to 250 parts by weight) and the component [III] is 1 to 50 parts by weight with respect to 100 parts by weight of the component [I]. Parts (particularly 5 to 15 parts by weight), component [IV] is 50 to 200 parts by weight (particularly 60 to 120 parts by weight), component [V] is 1 to 50 parts by weight (particularly 5 to 20 parts by weight), filler Is preferably 200 to 500 parts by weight (particularly 250 to 350 parts by weight).

  The light / thermosetting resin composition may be prepared, for example, by mixing the components [I] to [V] and additives as necessary, uniformly dispersing, and then vacuum degassing. The order of addition of each blending component is not particularly limited, and each blending component may be added sequentially or all blending components may be added at once.

  The light / thermosetting resin composition prepared as described above preferably has a resin viscosity (Pa · S, room temperature) of 10 to 50, particularly 15 to 30 in consideration of applicability to a printed wiring board.

  Hereinafter, the present invention will be described in detail with reference to the drawings.

  In the method for producing a planarized resin-coated printed wiring board of the present invention, a printed wiring board having through holes [FIGS. 1A and 103] is used as a printed wiring board as a material. The through hole includes all kinds of holes penetrating through the printed wiring board. Specifically, examples of the through hole include a through via hole, a component hole, and other through holes. A double-sided printed wiring board is mentioned as a kind of printed wiring board. Examples of the double-sided printed wiring board include a rigid printed wiring board, a flexible printed wiring board, and a rigid / flex printed wiring board.

  The printed wiring board having the through holes is preferably one in which the surface of the conductive layer [FIGS. 1A and 102] is roughened in order to improve the adhesion between the conductive layer and the resin layer. Examples of the conductive layer include a conductive metal layer, particularly a circuit layer, a plated metal layer on the inner wall of a through hole (such as a through hole), and a metal foil layer. As the roughening treatment, blackening treatment, so-called “CZ (chemical roughening agent manufactured by Mech Etch Bond)”, blackening reduction treatment, acicular alloy plating, physical treatment (sand blasting, shot blasting, buffing) Etc.).

  In the method for producing a flattened resin-coated printed wiring board of the present invention, first, a photo / thermosetting resin composition is applied to one surface and a through hole of a printed wiring board having a through hole.

  The application of the light / thermosetting resin composition may be performed by, for example, screen printing (mask printing using a polyester screen or stainless screen, etc.), metal mask printing, roll coating printing, or the like.

  In addition, if a vacuum printer is used, generation | occurrence | production of the bubble in coating resin can be prevented. Furthermore, defoaming of the resin can be performed by heating the coating resin (for example, 80 to 120 ° C., 10 to 60 minutes) to reduce the resin viscosity.

  In the present invention, the entire surface of the printed wiring board is coated with the resin layer [FIGS. 1B and 105] by the above-described application, but in particular, concave portions (such as concave portions between circuits) on the surface of the printed wiring board [FIG. , 104] and the through holes are also filled (filled) with a coating resin [FIG. 1B]. Conventionally, the recesses between the circuits of the printed wiring board are covered with a resist, a prepreg, a semi-cured resin, an adhesive sheet, and other interlayer materials without being filled with resin in advance.

  However, if the recesses between the circuits are not filled in advance, even if an interlayer material is subsequently filled into the recesses between the circuits by vacuum pressing, filling is likely to be difficult and incomplete. In particular, in a high-density circuit, lines and spaces are narrow, and it is difficult to fill recesses between circuits with interlayer materials. Therefore, a slight gap is generated in the recesses between the circuits, and air may remain in the gap. As a result, when a high temperature (for example, 200 to 300 ° C.) is applied to the printed wiring board due to reflow during component mounting in the subsequent process, the remaining air expands and the surface of the coating film bulges (so-called popcorn phenomenon). May occur [FIGS. 6E, 625 and FIGS. 7C, 725].

  On the other hand, if the space between the circuits is large, it can be completely filled. However, when the space is completely filled, the interlayer material corresponding to a large space volume between the circuits is used for filling. A depression may occur on the surface of the coating resin layer [FIGS. 6E and 626 and FIGS. 7C and 726]. Any of the above bulges and dents on the coating surface significantly impairs the flatness of the printed wiring board.

  Therefore, in order to achieve high flatness of the printed wiring board, not only the through hole of the printed wiring board but also the recess on the surface of the printed wiring board (such as a recess between circuits) is a light / thermosetting resin. It is important to fill

In the method for producing a flattened resin-coated printed wiring board of the present invention, after the above-mentioned photo / thermosetting resin composition is applied and filled, the following steps 1) and 2) are sequentially performed. That is,
1) The process of planarizing the coating resin surface.
2) A step of photocuring the coating resin.

  Specifically, in step 1), the printed and filled printed wiring board is first sandwiched between two cover films [FIGS. 1C and 106]. The cover film can be peeled off from the printed wiring board after first-stage light curing described below, and preferably transmits the irradiation light satisfactorily. Specifically, examples of such a cover film include a PET film, a PEN film, a PP film, and a PE film. The film thickness of the cover film may be, for example, 10 to 200 (typically 25 to 100) μm.

  Thereafter, the printed wiring board covered with the cover film is placed on a pressure roll. The pressure roll can be performed by a laminator or the like, for example. That is, first, the printed wiring board covered with the cover film is sandwiched between two rollers [FIG. 1D, 107].

  In this case, the distance between the rollers is such that the coating resin layer thickness [FIGS. 1I and 111] on the circuit of the printed wiring board is 0.1 to 10 (particularly 0.1 to 5) μm after the resin is cured. It is preferable to adjust to. Furthermore, the thickness of the coated resin layer on the insulating substrate of the printed wiring board [FIG. 1I, 112] is preferably +0.1 to +10 (particularly +0.1 to +5) μm after the resin is cured. If the layer thickness of the cured resin is too thin, the roughened copper foil may not be sufficiently covered. Conversely, if the thickness of the cured resin is too thick, it is necessary to polish the cured resin layer to expose the copper foil surface afterwards, or to provide an opening described later, Opening work may not be easy. As a result, the dimensional change of the printed wiring board occurs, and there may be a problem that the resin remains in the opening, or the error between the impedance design value and the actual value becomes large.

  Thereafter, the two rollers move over the entire surface of the cover film covered on both sides of the printed wiring board while maintaining the above-mentioned distance between the rollers [FIGS. 1D and 108].

  Specifically, the laminating conditions include a laminating pressure of 0.01 to 10 (typically 0.1 to 1) MPa, a laminating speed of 0.1 to 10 (typically 0.3 to 3) m / m. Minutes, lamination temperature from room temperature to 150 (typically 25 to 100) ° C.

  In the method for producing a flattened resin-coated printed wiring board of the present invention, after step 1) is performed, step 2) is performed. In step 2), the light irradiation is preferably performed from both sides of the printed wiring board. In this case, light may be irradiated simultaneously from both sides (front side and back side) of the printed wiring board, or light may be sequentially irradiated from one side. The coating resin is irradiated with light through the cover film, and as a result, first-stage photocuring of the coating resin occurs [FIG. 1E, 109].

Light irradiation is, for example, light in the characteristic absorption wavelength region of component [III], specifically, ultraviolet light having a wavelength of 200 to 400 nm at a light irradiation amount of 0.5 to 10 J / cm ² at −20 to 80 ° C. And you can go. The photocuring may be performed using an in-liquid exposure apparatus described in JP-A-9-6010 and JP-A-10-29247.

  After the photocuring, the cover films respectively covered on both sides of the printed wiring board are peeled off and removed.

  In the method for producing a flattened resin-coated printed wiring board of the present invention, after the steps 1) and 2) are completed as described above, the photo / thermosetting resin composition is also applied to the other surface of the printed wiring board. Apply the object [FIG. 1F, 105]. The application may be performed in the same manner as when one surface of the printed wiring board is applied.

Thereafter, the steps 1) [FIG. 1G, FIG. 1H] and 2) are sequentially performed in the same manner as described above. In the method for producing a flattened resin-coated printed wiring board of the present invention, the following step 3) is then performed.
3) A step of thermosetting the photocurable resin.

  In step 3), the coating resin cured in the first step in the step 2) is second-stage heat-cured to be completely cured [FIG. 1I, 110]. By this complete curing, excellent heat resistance, solder resistance, and adhesion between the cured resin and the printed wiring board can be obtained.

  As heating conditions in the step 3), the reaction start temperature (second stage thermosetting start temperature) of the component [V] of the photo / thermosetting resin composition is higher than, specifically 120 to 300 (particularly 140 to 200). Heating at 30 ° C. for 30 to 200 minutes is preferred.

  As described above, in the method for producing a flattened resin-coated printed wiring board according to the present invention, it is not necessary to perform hot pressing (that is, it is not necessary to perform heating and pressurizing simultaneously), so that deformation of the resin is prevented. It is possible to prevent the flatness of the printed wiring board from being lowered.

  The flattened resin-coated printed wiring board of the present invention obtained as described above generally has a maximum difference in unevenness on the surface of 3 (typically 1) μm or less.

  The flattened resin-coated printed wiring board [FIG. 1I] of the present invention produced as described above has a recessed portion (particularly a recessed portion between circuits) and a through hole of the printed wiring board filled with a cured resin, And the surface is covered with a very flat and uniform cured resin layer (film).

  Therefore, the flattened resin-coated printed wiring board of the present invention has a uniform thickness over the entire printed wiring board (all areas) regardless of the density of the circuit, and on the conductive circuit layer (circuit copper foil). The thickness of the coated resin layer is constant.

  A multilayer printed wiring board (particularly a four-layer printed wiring board) useful as an inner layer material of the multilayer printed wiring board can be produced using the planarized resin-coated printed wiring board of the present invention as a raw material.

  That is, in the multilayer printed wiring board of the present invention, first, a photo / thermosetting resin composition is applied to one surface and a through hole of a printed wiring board having a through hole, and steps 1) and 2) are sequentially performed. Next, after applying the photo / thermosetting resin composition to the other surface of the printed wiring board and sequentially performing steps 1) and 2), the following step A is performed.

  A) A step of performing step 3), and then laminating and pressing the printed wiring board by sandwiching the printed wiring board with the pressure bonding material.

  In the step A), when the step 3) is completed, as described above, first, the planarized resin-coated printed wiring board of the present invention is obtained.

  Thereafter, the flattened resin-coated printed wiring board of the present invention is sandwiched between the pressure-bonding materials [FIG. 2A, 213] and laminated and pressed to pressure-bond the pressure-sensitive material. Examples of the pressure-bonding material include a prepreg, a copper foil with resin, a semi-cured resin film, an adhesive sheet, a dry film, a resist, and the like. Typically, a prepreg is used. The thickness of the pressure bonding material may be, for example, 50 to 100 μm. A plurality of pressure-bonding materials may be used as necessary.

  The lamination press is preferably performed under heating when the pressure-bonding material is a semi-thermosetting resin. In the case where the heating is performed at a temperature equal to or higher than the second-stage thermosetting temperature of the light / thermosetting resin composition (particularly, the reaction start temperature of the component [V]), the above-described flattened resin-coated printed wiring board. In step (3), step 3) can be omitted.

  That is, in this case, first, a light / thermosetting resin composition is applied to one surface and a through hole of a printed wiring board having a through hole, and steps 1) and 2) are sequentially performed, After applying the thermosetting resin composition to the other surface of the printed wiring board and sequentially performing steps 1) and 2), the following step B is performed.

  B) A step in which a printed wiring board is sandwiched between pressure-bonding materials and laminated and pressed at a temperature equal to or higher than the thermosetting temperature of the photo-curing resin to simultaneously press the pressure-bonding material and the step 3).

  In the step B), the press-bonding (and complete thermosetting) of the pressure-bonding material and the second-stage thermosetting of the photo-curing resin [ie, step 3)] are simultaneously performed by laminating and pressing at the thermosetting temperature or higher. .

In the step A) or B), the lamination press conditions are, for example, 120 to 200 (particularly 135 to 180) ° C., 30 to 180 (particularly 60 to 150) minutes, pressure 10 to 100 (particularly 15 to 40) kgf / cm. ² is preferred.

  The lamination press can be performed by, for example, an open lamination apparatus, a vacuum lamination apparatus, or the like. Furthermore, these laminating apparatuses may be, for example, a hydraulic press, an autoclave press or the like. Furthermore, the vacuum hydraulic press may be a frame type, a box type, or the like.

In the method for producing a multilayer printed wiring board according to the present invention, after performing the above-mentioned step A) or B), drilling is performed from the surface of the pressure-bonding material to the conductor layer (for example, the circuit layer). 2B, 214]. This micro via is used as a conformal via for interlayer connection with a circuit layer formed in a later process. Drilling can be performed by a method using a laser (UV laser, CO ₂ laser, excimer laser, Nd: YAG laser, etc.) or plasma, for example. The diameter of the micro via is preferably, for example, 10 to 200 (particularly 20 to 70) μm.

  Next, in the method for producing a multilayer printed wiring board according to the present invention, the entire surface is plated [FIG. 2C, 215]. The entire surface plating is preferably performed on both sides. By this whole surface plating, the entire exposed surface (the surface of the pressure bonding material, the inner wall surface of the micro via, the exposed surface of the conductor layer opened by the micro via, etc.) is covered with the plating layer. This plating layer is used for interlayer connection and circuit formation in a subsequent process.

  In the entire surface plating, it is preferable to first perform electroless plating to form a so-called base, and then perform further electrolytic plating. Examples of “plating” in electroless plating and electrolytic plating include copper plating, nickel plating, gold plating, nickel-gold plating, solder plating, and the like. The layer thickness of electroless plating is preferably 0.1 to 10 (particularly 0.5 to 5) μm, and the layer thickness of electrolytic plating is preferably 10 to 50 (particularly 15 to 30) μm.

  Next, in the method for producing a multilayer printed wiring board of the present invention, a circuit [FIG. 2D, 216] is formed from the entire plating layer. The circuit formation can be performed, for example, by a subtractive method or an additive method.

  Next, in the method for producing a multilayer printed wiring board of the present invention, the surface is coated with a resist [FIG. 2E, 217]. Examples of the resist include a solder resist, a polyimide resist, a polyimide film, and the like. Typically, the resist is a solder resist.

  The resist can be coated by, for example, a photographic method in which exposure and development are performed using a photosensitive resist ink or a dry film, a printing method using a resist ink, and the like.

  The resist may have openings as necessary. In this case, exposure / development or ink printing is performed so that a resist pattern having an opening is obtained. Specifically, the openings of the resist may be provided for providing pads [FIGS. 2E and 218] and / or terminal portions [FIGS. 2E and 219] on the multilayer printed wiring board. In this case, the multilayer printed wiring board is covered with a resist mask except for the pads and / or terminals.

  The pad surface and / or the terminal portion surface exposed by the resist openings are further subjected to pad plating [FIG. 2F, 220] and / or terminal plating [FIG. 2F, 221] in order to improve the friction resistance. It's okay. The pad plating and / or terminal plating may be formed, for example, by first performing nickel plating and then further performing gold plating. The plating layer thickness is preferably 0.1 to 20 (particularly 0.5 to 10) μm.

  The multilayer printed wiring board of the present invention manufactured as described above [FIG. 2F] has a dense circuit of the core portion (that is, the portion corresponding to the flattened resin-coated printed wiring board of the present invention used as a material). Regardless of the degree, there are no bulges or depressions on the surface, extremely excellent flatness has been achieved, and an insulating layer (cured resin layer and pressure bonding material) on the conductive circuit layer (circuit copper foil) in the core part The thickness of the layer) is also very constant.

  Using the flattened resin-coated printed wiring board of the present invention as a raw material, a printed wiring board (particularly a double-sided printed wiring board) useful as an outer layer material of a multilayer printed wiring board can be produced. That is, in the method for producing a printed wiring board of the present invention, a photo / thermosetting resin composition is applied to one surface and a through hole of a printed wiring board having a through hole, and steps 1) and 2) are sequentially performed. Next, a photo / thermosetting resin composition is applied to the other surface of the printed wiring board, and steps 1) to 3) are sequentially performed to obtain the flattened resin-coated printed wiring board of the present invention [ FIG. 3A].

  Next, an opening is provided in the coating resin (cured resin) layer of the flattened resin-coated printed wiring board. In this embodiment, the coating resin layer functions as a resist [FIG. 3B].

The opening of the coating resin layer may be formed by a method using a laser (UV laser, CO ₂ laser, excimer laser, Nd: YAG laser, etc.) or plasma, as described above. Specifically, the opening of the covering resin layer may be provided for providing a pad [FIG. 3B, 318] and / or a terminal portion [FIG. 3B, 319] on the printed wiring board. Furthermore, the pad surface and / or the terminal portion surface may be subjected to pad plating [FIGS. 3C and 320] and / or terminal plating [FIGS. 3C and 321].

  The printed wiring board of the present invention produced as described above [FIG. 3C] has no bulges or depressions on its surface, and extremely high flatness is achieved. Therefore, it is excellent in the positional accuracy at the time of high-density mounting of minute parts, and the thickness is uniform over the entire printed wiring board regardless of the density of the circuit, and a flat resin layer (especially a solder resist film). It is covered. As a result, the penetration of the underfill is excellent when a narrow pitch BGA (ball grid array), for example, a BGA having a bump pitch of 100 μm or less is mounted.

  Although the present invention has been described above, it is easy for those skilled in the art to further modify and extend the present invention. For example, in the method for producing a multilayer printed wiring board according to the present invention, instead of performing “entire plating and forming a circuit from a plating layer”, “plating resist [FIG. 4A, 422] is formed and covered with plating resist”. Plating [FIGS. 4B and 415] may be applied to the non-existing portions to form circuits [FIGS. 4C and 416].

  Furthermore, a multilayer printed wiring board having a desired number of layers can be produced by repeating each production process in the method for producing a multilayer printed wiring board of the present invention.

  Furthermore, in the method for producing a multilayer printed wiring board of the present invention, “copper foil with resin” [FIGS. 5A, 523 and 524] may be used as the “crimping material”. In this case, the “entire plating” in the subsequent step can be omitted. [Fig. 5]

  Furthermore, if the flattening resin-coated printed wiring board, multilayer printed wiring board, and printed wiring board of the present invention are appropriately combined and used as an inner layer material or an outer layer material, and these are laminated and pressed, the number of layers is increased. A desired hole-filling multilayer printed wiring board having a more complicated layer structure can be manufactured.

  Furthermore, in any production method of the present invention, instead of the prepreg, other adhesive sheets, other interlayer materials, or resin-coated copper foil can be used, and as a result, a hole-filled multilayer printed wiring board having a desired layer structure is produced. can do.

  Furthermore, in the production method of the present invention, the case where step 1) is performed by a pressure roll using a cover film has been described, but other than the film (mold, plate, sheet, etc.) may be used. Can be used by any other method capable of flattening the surface of the coated resin instead of the pressure roll.

Hereinafter, the present invention will be described more specifically with reference to the drawings.
<Preparation of light / thermosetting resin composition>
Preparation Example 1
Each compounding component shown below was stirred and mixed. Subsequently, it was uniformly dispersed with a three-roll mill. The obtained uniform dispersion was vacuum degassed to prepare a photo / thermosetting resin composition (Preparation Example 1).

Light / thermosetting resin composition (parts by weight):
40% methacrylic acid adduct of dicyclopentadiene phenol type epoxy resin (100), dicyclopentanyl methacrylate (30), trimethylolpropane triacrylate (70), dipentaerythritol hexaacrylate (80), 2-methyl-1 [4- (Methylthio) phenyl] -2-morpholinopropan-1-one (10), diethylthioxanthone (1), bisphenol A type epoxy resin ¹⁾ (80), bisphenol AD type epoxy resin (20), dicyandiamide ( 10), silica (250), surface-treated colloidal silica (6), polydimethylsiloxane (3).

    1): A mixture of n = 0 (86 wt%) and n = 1 (14 wt%) in the above formula [Formula IVl-1], average molecular weight 380.

<Preparation of thermosetting / thermosetting resin composition>
Preparation Example 2
Each compounding component shown below was stirred and mixed. Subsequently, it was uniformly dispersed with a three-roll mill. The obtained uniform dispersion was vacuum degassed to prepare a thermo-thermosetting resin composition (Preparation Example 2).

Thermo-thermosetting resin composition (parts by weight):
Triphenylmethane type epoxy resin (19), N, N, O-tris (glycidyl) -p-aminophenol (28), dicyandiamide (2), epoxy resin amine adduct (1), aluminum hydroxide (49), bentonite (0.5), polydimethylsiloxane (0.5).

<Manufacture of printed wiring boards>
Example 1
As a double-sided printed wiring board, a circuit layer [FIGS. 1A, 102] is provided on both sides of an insulating substrate [thickness 0.930 mm, FIGS. 1A, 101], and inner walls of through holes [FIGS. 1A, 103] are copper-clad. [Copper circuit thickness is 40 μm, line / space (L / S) = 20 μm / 40 μm, through hole diameter is 100 μm after plating]. The surface of the conductive layer (the copper-clad portion of the inner wall of the circuit and the through hole) was subjected to roughening treatment in advance with “MEC etch bond CZ-8101” (manufactured by MEC, chemical roughening chemical).

  The photo / thermosetting resin composition (Preparation Example 1) [FIGS. 1B and 105] is screen-printed under the printing conditions shown in Table 5 below, and is applied to one side (leading side) of the printed wiring board. The through holes and the recesses between the circuits [FIG. 1B, 104] were filled and filled.

  Next, the printed wiring board was placed on a horizontal rack and heated with a BOX dryer at 80 ° C. for 30 minutes to reduce the viscosity and remove bubbles in the coating resin. This photo / thermosetting resin composition (Preparation Example 1) was examined with a 50 × microscope, and it was confirmed that no bubbles were present between the circuits.

  Next, the printed wiring board was sandwiched between 100 μm-thick PET films [FIG. 1C, 106] and applied to a laminator. That is, this film-coated printed wiring board is sandwiched between two stainless steel rollers [FIG. 1D, 107] (lamination pressure 0.1 MPa, laminating speed 0.5 m / min, laminating temperature 100 ° C.), Moved on film [FIG. 1D, 108]. Thus, the coated resin layer on the surface of the printed wiring board was flattened and thinned [FIG. 1D].

Next, the printed wiring board was irradiated with light at an exposure amount of 1200 mj / cm ² using a high-pressure mercury lamp to form a first-stage photocured product [FIG. 1E, 109], and then the PET film on both sides. Was removed by stripping [FIG. 1E].

  Next, the back surface (following surface) of the printed wiring board was treated in the same manner as the preceding surface. That is, the photo / thermosetting resin composition (Preparation Example 1) [FIGS. 1F and 105] was screen-printed under the printing conditions shown in Table 5, and the entire surface of the other side (following side) of the wiring board was formed. It was applied and filled the recesses [FIG. 1F, 104] between the circuits [FIG. 1F].

  Next, the printed wiring board was placed on a horizontal rack and heated with a BOX dryer at 80 ° C. for 30 minutes to reduce the viscosity and remove bubbles in the coating resin. This photo / thermosetting resin composition (Preparation Example 1) was examined with a 50 × microscope, and it was confirmed that no bubbles were present between the circuits.

  Next, this printed wiring board was sandwiched between PET films having a thickness of 100 μm [FIGS. 1G, 106]. This film-covered printed wiring board is sandwiched between two stainless steel rollers [FIG. 1G, 107] (lamination pressure 0.1 MPa, laminating speed 0.5 m / min, laminating temperature 100 ° C.), and the roller is placed on the film. Moved [FIG. 1G, 108]. Thus, the coating resin layer on the surface of the printed wiring board was flattened and thinned [FIG. 1H].

Next, the printed wiring board was irradiated with light at an exposure amount of 1200 mj / cm ² using a high-pressure mercury lamp to form a first-stage photocured product, and then the PET films on both sides were peeled off and removed.

  Thereafter, the printed wiring board is heated at 150 ° C. for 30 minutes to perform second-stage thermosetting of the photocurable resin [FIG. 1I, 110], and the flattened resin-coated printed wiring according to the present invention having a total thickness of 1.018 mm. A plate (Example 1) was produced [FIG. 1I].

Example 2
As a double-sided printed wiring board, a circuit layer is provided on both sides of an insulating substrate with a thickness of 0.930 mm, and the inner wall of the through hole is copper-clad [copper circuit thickness is 40 μm, L / S = 20 μm / 40 μm, through hole The diameter was 100 μm after plating]. Note that the surface of the conductive layer (the copper-clad portion of the inner wall of the circuit and the through hole) was roughened with Mec Etch Bond CZ-8101 in advance.

  The photo / thermosetting resin composition (Preparation Example 1) is screen-printed under the printing conditions shown in Table 5 using a vacuum printing machine, and is applied to the entire surface of one side (leading side) of the wiring board. The through holes and the recesses between the circuits were filled and filled.

  Next, the printed wiring board was sandwiched between 100 μm-thick PET films and applied to a laminator. That is, this film-coated printed wiring board was sandwiched between two stainless steel rollers (lamination pressure 0.1 MPa, laminating speed 0.5 m / min, laminating temperature room temperature), and the roller was moved on the film. Thus, the coating resin layer on the surface of the printed wiring board was made flat and thin.

Next, the printed wiring board was irradiated with light at an exposure amount of 1200 mj / cm ² using a high-pressure mercury lamp to form a first-stage photocured product, and then the PET films on both sides were peeled off and removed.

  Next, the back surface (following surface) of the printed wiring board was treated in the same manner as the preceding surface. That is, the photo / thermosetting resin composition (Preparation Example 1) was screen-printed under the printing conditions shown in Table 5 using a vacuum printing machine, and the other one side (rear side) of the wiring board was used. The front surface was applied to fill the recesses between the circuits.

  Next, this printed wiring board was sandwiched between PET films having a film thickness of 100 μm. This film-coated printed wiring board was sandwiched between two stainless steel rollers (lamination pressure 0.1 MPa, laminating speed 0.5 m / min, laminating temperature room temperature), and the roller was moved on the film. Thus, the coating resin layer on the surface of the printed wiring board was made flat and thin.

Next, the printed wiring board was irradiated with light at an exposure amount of 1200 mj / cm ² using a high-pressure mercury lamp to form a first-stage photocured product, and then the PET films on both sides were peeled off and removed.

  Thereafter, this printed wiring board is heated at 150 ° C. for 30 minutes to perform second-stage thermosetting of the photocurable resin, and the flattened resin-coated printed wiring board of the present invention having a total thickness of 1.030 mm (Example 2) Manufactured.

Example 3
A four-layer printed wiring board was manufactured using the printed wiring board (Example 1) as a material. That is, first, a 0.1 mm thick prepreg [FIG. 2A, 213] was covered and sandwiched on both surfaces of the printed wiring board (Example 1).

  Subsequently, according to the press conditions of Table 6, the said printed wiring board was heated and vacuum-pressed, and the prepreg was crimped | bonded.

  Next, laser irradiation was performed from the surface of the prepreg of the printed wiring board to expose the circuit layer [FIG. 2B, 202] to form micro vias (via diameter 70 μm) [FIG. 2B, 214] [FIG. 2B].

  Next, copper plating (first electroless copper plating and then electrolytic copper plating) is performed on both surfaces of the printed wiring board and the inner wall surface of the micro via [FIG. 2C, 215], and the surfaces of the via and the prepreg are made of copper foil. And a double-sided copper-clad laminate was formed. The plating thickness was 1 μm for electroless copper plating and 14 μm for electrolytic plating.

  Next, a circuit [FIG. 2D, 216] was formed on both surfaces of the double-sided copper-clad laminate as follows. First, an etching resist was formed by a dry film (laminate) method. That is, a dry film was laminated on both surfaces of the double-sided copper-clad laminate, a negative film (pattern mask) was overlaid, and exposed and cured with an ultra-high pressure mercury lamp.

  Next, the carrier film of the dry film was peeled off, and a developer (1% sodium carbonate solution) was sprayed and developed on the exposed resist surface from a spray nozzle, and then washed with water to form a resist pattern.

  Next, etching was performed. That is, a ferric chloride solution (36% by weight) was sprayed from both sides of the resist-coated double-sided copper-clad laminate from a spray nozzle to dissolve and remove unnecessary copper foil. After completion of the etching, a 3% aqueous sodium hydroxide solution was sprayed from a spray nozzle to wash away the etching resist while swelling.

  After forming a circuit as described above, a solder resist ink was applied to form a solder resist [FIG. 2E, 217]. That is, first, UV / thermosetting acrylate / epoxy mixed resin was screen printed on both surfaces on which the circuit was formed with a squeegee (squeegee hardness 75) through a 150 mesh Tetron screen.

Next, after baked in a warm air drying oven at 75 to 80 ° C., a negative film was adhered and cured by exposure (300 mj / cm ² ). Then, development was performed with a 1% sodium carbonate solution (30 ° C., 2.5 kg / cm ² ) to form openings (pad portions [FIG. 2E, 218] and terminal portions [FIG. 2E, 219]). Then, it heated at 150 degreeC for 30 minutes, and performed thermosetting.

  Thereafter, the pad portions [FIGS. 2E and 218] and the terminal portions [FIGS. 2E and 219] were first subjected to electrolytic nickel and then gold plating [FIGS. 2F, 220 and 221].

  As described above, the thickness of the insulating layer on the circuit dense portion in the core portion is constant (uniform), and the thickness of the insulating layer on the circuit depopulated portion is constant (uniform), and the surface is swollen or depressed. A four-layer printed wiring board of the present invention (Example 3) [Fig.

Example 4
A double-sided printed wiring board was manufactured using the printed wiring board (Example 2) as a material. That is, first, the coated cured resin layer [FIG. 3A, 310] of the printed wiring board (Example 2) is irradiated with laser, and the circuit layer of the pad portion [FIG. 3B, 318] and the terminal portion [FIG. The copper foil was exposed [FIG. 3B].

  Then, electrolytic nickel and then electrolytic gold plating [FIGS. 3C and 321] were applied to the pad portions [FIGS. 3C and 318] and the terminal portions [FIGS. 3C and 319].

  As described above, the thickness of the insulating layer on the circuit dense portion is constant (uniform) and the thickness of the insulating layer on the circuit depopulated portion is constant (uniform), and there is no swelling or depression on the surface. A double-sided printed wiring board according to the present invention (Example 4) having a total thickness of 1.030 mm was produced [FIG. 3C].

Comparative example 1
A double-sided printed wiring board having a circuit layer [FIGS. 6A, 602] on both sides of an insulating substrate [FIGS. 6A, 601] having a thickness of 0.930 mm, and the inner wall of the through hole being copper-clad [copper circuit thickness is 40 μm, L / S = 20 μm / 40 μm, and through-hole diameter of 100 μm after plating] was used. Note that the surface of the conductive layer (the copper-clad portion of the inner wall of the circuit and the through hole) was roughened with Mec Etch Bond CZ-8101 in advance.

  On the printed wiring board, the thermo-thermosetting resin composition (Preparation Example 2) [FIG. 6A, 605] is screen-printed under the printing conditions shown in Table 5, and the recesses between the circuits are filled with the resin. Instead, only through holes were filled and filled.

  Next, the printed wiring board was heated at 130 ° C. for 60 minutes to form a first-stage thermoset [FIG. 6B, 609] [FIG. 6B]. Was polished once with a No. 600 and further polished four times with a 600 buff [FIG. 6C].

  Next, a prepreg [FIG. 6D, 613] was covered and sandwiched on both surfaces of the printed wiring board. The thickness of the prepreg was 0.1 mm.

  Next, the printed wiring board was heated and vacuum-pressed according to the pressing conditions shown in Table 6, and the prepreg crimping and the first-stage thermosetting resin were simultaneously performed to produce a printed-wiring board [FIG. 6E]. (Comparative Example 1).

  About the obtained printed wiring board (comparative example 1), the following malfunction was seen. That is, in the densely packed portion of L / S = 20 μm / 40 μm, filling with the prepreg was incomplete, air remained between the circuits, and the surface swelled [FIGS. 6E and 625].

  Furthermore, in the circuit depopulated portion of L / S = 20 μm / 200 μm, the filling with the prepreg was complete, but a depression due to filling and consumption of the prepreg was generated between the circuits [FIGS. 6E and 626].

Comparative example 2
A four-layer printed wiring board was manufactured using the printed wiring board (Comparative Example 1) as a material. That is, a four-layer printed wiring board (Comparative Example 2) was produced in the same manner as in Example 3 except that Comparative Example 1 was used instead of Example 1 as the printed wiring board.

  However, a four-layer printed wiring board manufactured (comparative) due to the presence of swelling [FIGS. 6E, 625] and depressions [FIGS. 6E, 626] on the surface of the printed wiring board (Comparative Example 1) of the material (core material). Example 2) The surface also swelled [FIGS. 9A, 925] and dents [FIGS. 9B, 926].

<Manufacture of bump-formed BGA component-mounted printed wiring board>
Production Example 1 and Comparative Production Example 1
Bumps in BGA parts [average value of bump height 33.4 μm, standard deviation of bump height 1.5] and a pad portion of a four-layer printed wiring board (each Example 3 and Comparative Example 2) are bump-connected. Thus, BGA component-mounted printed wiring boards were produced (Each Production Example 1 and Comparative Production Example 1).

<Characteristic evaluation of printed wiring board>
For each printed wiring board, each cured film thickness of the coated resin on the circuit and on the insulating substrate (Examples 1 and 2), (four layers) maximum swelling and maximum depression on each printed wiring board surface (each Example 1 and 2, Comparative Example 1, Manufacturing Example 1 and Comparative Manufacturing Example 1), (4-layer) standard deviation of flatness of printed wiring board (size of variation in thickness at each part of printed wiring board) Examples 1 and 2, Comparative Example 1, Manufacturing Example 1 and Comparative Manufacturing Example 1), average value of bump height after mounting a BGA component (Manufacturing Example 1 and Comparative Manufacturing Example 1), and bump bondability (Manufacturing Example 1) And Comparative Production Example 1) were measured and evaluated.

  The BGA used for the evaluation had a size of 16.0 mm × 16.0 mm, a plate thickness of 0.4 mm, a bump pitch of 75 μm, and a number of bumps of 148.

  In Tables 7 and 8, “blowing amount” and “dent amount” are based on the surface portion (ie, flat surface portion) of the (4-layer) printed wiring board surface where “swell” and “dent” do not occur. The height of the bulge and the depth of the dent, respectively, when the surface is used.

  The cured film thickness of the coated resin, the amount of swelling and depression on the surface, and the bump height after mounting the BGA component were measured by a cross section method. The standard deviation of the flatness of the surface of the printed wiring board (Embodiments 1 and 2 and Comparative Example 1) is assumed on the surface of the printed wiring board at 2 mm intervals, and the printed wiring board at the intersection of 25 vertical and horizontal lines. Each total thickness was measured and determined. The standard deviation s of the flatness of the surface of the four-layer printed wiring board (each Example 3 and Comparative Example 2) was obtained by measuring the total thickness of each pad plating part on the surface.

  Furthermore, the bump bondability was evaluated as follows. That is, the average value h (= 33.4 μm) of bump height before bump connection, the average value h ′ of bump height after bump connection (after mounting BGA components), and the standard of flatness on the surface of the four-layer printed wiring board When the deviation s and the standard deviation ρ (= 1.5) of the bump height before the bump connection are in a relationship satisfying the formula (1) in Table 9, “◯ (good bump bonding)”, formula ( When the relationship satisfying 2) was satisfied, it was evaluated as “× (defective bump bonding)”. In formula (1) or (2), the left side represents the bump crushing amount (hereinafter sometimes referred to as “bump crushing”), and the right side represents the variation in flatness and bump height on the surface of the four-layer printed wiring board. And the total variation amount (hereinafter also referred to as “variation”).

  From Tables 7 and 8, the following is clear. That is, the flattened resin-coated printed wiring board (Examples 1 and 2) and the four-layer printed wiring board (Example 3) of the present application are the same as the conventional (four-layer) printed wiring board (Comparative Example 1 and Comparative Manufacturing Example 1). As compared with the above, the unevenness on the surface of the printed wiring board is small (because the sum of the maximum swelling amount and the maximum depression amount is small), and the printed wiring board surface is extremely flat (because the standard deviation of flatness is small).

  Further, when the BGA component is mounted (bump connection) on the four-layer printed wiring board of the present application (Example 3) (Manufacturing Example 1), “the bump collapse amount is larger than the total variation amount”. Can absorb the "variation", so that all the bumps are securely bonded.

  On the other hand, when the BGA component is mounted (bump connection) on a conventional four-layer printed wiring board (Comparative Example 2) (Comparative Production Example 1), the “bump crushing amount is smaller than the total variation amount”. Since “variation” cannot be absorbed by “crushed”, some bumps cannot be joined.

  That is, as shown in FIG. 9A, when the amount of swelling is too large, the bump 932a existing on the swelling 925 cannot be crushed to the extent that the pad plating 920 and the bump 932b can be joined (because the bump 932a Because the amount of “collapsed bumps” has already reached its limit). As a result, the bump 932b cannot be bump-connected to the pad plating 920.

  Similarly, as shown in FIG. 9B, when the amount of depression is too large, the bump 932a cannot be crushed to the extent that the pad plating 920 and the bump 932b existing in the depression 926 can be joined (because the bump 932a Because the amount of “collapsed bumps” has already reached its limit). As a result, the bump 932b cannot be bump-connected to the pad plating 920.

It is a manufacturing-process figure of the planarization resin coating printed wiring board (especially Example 1) which concerns on this invention. It is a manufacturing-process figure of the 4 layer printed wiring board (especially Example 3) which concerns on this invention. It is a manufacturing-process figure of the double-sided printed wiring board (especially Example 4) which concerns on this invention. It is a manufacturing-process figure of the 4 layer printed wiring board of the aspect which modified / expanded the 4 layer printed wiring board based on this invention. It is a manufacturing-process figure of the 4 layer printed wiring board of another aspect which modified / expanded the 4 layer printed wiring board based on this invention. It is a manufacturing-process figure of the hole-filled printed wiring board which grind | polishes of the comparative example 1. FIG. It is a manufacturing-process figure of the hole-filled printed wiring board which does not fill resin into the recessed part between circuits in the conventional method previously. It is the elements on larger scale (A) of a swelling peripheral part, and the elements on larger scale (B) of a peripheral part of a hollow in the conventional printed wiring board which has a hollow and a swelling. It is a partial expanded sectional view in the vicinity of a bump bonding part to show that a bump bonding defect occurs when a BGA component is bump-connected to a conventional four-layer printed wiring board having a depression and a swelling. A is a partially enlarged cross-sectional view showing bump bonding failure in the vicinity of swelling on the surface of the four-layer printed wiring board. B is a partially enlarged cross-sectional view showing bump bonding failure in the vicinity of a dent on the surface of the four-layer printed wiring board.

Explanation of symbols

101,601,701,801 Insulating substrate 102,202,502,602,702,802
Conductive circuit layer 103 Through hole (through hole)
104, 704a, 704b Recesses 105, 605, 705 between circuits Uncured resin composition 106 Cover film 107 Roller 108 Direction in which the roller moves 109, 609 First-stage cured product 110, 310, 610 Second-stage cured product 111 Circuit Coating resin film thickness on 112 Coating resin film thickness on insulating substrate 213, 613 Pressure bonding material (prepreg)
214,514 Microvia 215,415,515 Plating layer 216,416,516 Conductor circuit (conductor pattern)
217,517 Resist 218,318,518,918 Pad part 219,319,519 Terminal part 220,320,520,920 Pad plating (electrolytic nickel-gold plating)
221,321,521 Terminal plating (electrolytic nickel-gold plating)
422 Plating resist 523 Copper foil portion 524 of resin-attached copper foil Resin portion 625, 725, 825, 925 Swelling 626, 726, 826, 926 Depression 727 Curing resist 728, 828 Curing resin 729 Swelling peripheral edge 730 Indentation peripheral portion 831 Thickness of insulating layer on conductive circuit layer 932a, 932b Bump 933 Surface layer portion 934 of 4-layer printed wiring board BGA component

Claims (7)

A light / thermosetting resin composition is applied to one surface of a printed wiring board having a through hole and a through hole, and the following steps 1) and 2) are sequentially performed, followed by the light / thermosetting resin composition. Is applied to the other surface of the printed wiring board, and the following steps 1) to 3) are sequentially performed.
1) The process of planarizing the coating resin surface.
2) A step of photocuring the coating resin.
3) A step of thermosetting the photocurable resin. The light / thermosetting resin composition is applied to one surface of the printed wiring board having the through hole and the through hole, and the following steps 1) and 2) are sequentially performed, and then the light / thermosetting resin composition is applied. After applying to the other surface of the printed wiring board and performing the following steps 1) and 2) sequentially,
A) The following step 3) is performed, and then the printed wiring board is sandwiched between the crimping materials and laminated and pressed to crimp the crimping material, or B) the printed wiring board is sandwiched between the crimping materials and the temperature is higher than the thermosetting temperature of the photo-curing resin. And then press the layers together to perform crimping of the crimping material and the following step 3),
A method for producing a multilayer printed wiring board, comprising: drilling from the surface of a pressure-bonding material to a conductor layer to form a micro via, plating the entire surface, forming a circuit from the plated layer, and then covering the resist.
1) The process of planarizing the coating resin surface.
2) A step of photocuring the coating resin.
3) A step of thermosetting the photocurable resin.   The method for producing a multilayer printed wiring board according to claim 2, wherein the resist has an opening. The light / thermosetting resin composition is applied to one surface of the printed wiring board having the through hole and the through hole, and the following steps 1) and 2) are sequentially performed, and then the light / thermosetting resin composition is applied. A method for producing a printed wiring board, comprising: applying to the other surface of the printed wiring board, sequentially performing the following steps 1) to 3), and then providing an opening in the coating resin layer.
1) The process of planarizing the coating resin surface.
2) A step of photocuring the coating resin.
3) A step of thermosetting the photocurable resin.   The method for producing a printed wiring board according to claim 3 or 4, wherein the surface exposed by the opening is coated by plating.   The method for producing a printed wiring board according to claim 1, wherein the surface of the conductive layer of the printed wiring board having a through hole is roughened.   The printed wiring board manufactured by the manufacturing method in any one of Claims 1-6.

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