Member for wiring board, method for manufacturing same, and method for manufacturing wiring board

Abstract

Provided is a method for manufacturing a member for a wiring board, the method comprising: (a) a step for preparing a first sheet including a base material and a first layer composed of a first resin composition with the base material being embedded in the first layer; (b) a step for heating a laminate comprising the first sheet and a second sheet composed of a second resin composition, with at least one outermost surface of the laminate being formed by the second sheet, and the laminate being heated while applying a pressing force in the thickness direction of the laminate; and (c) a step for flattening the outermost surface of the laminate after the step (b) such that the average surface roughness Ra of the outermost surface is 20 nm or less.

Description

Components for wiring boards and methods for manufacturing the same, and methods for manufacturing wiring boards

[0001] This disclosure relates to a component for a wiring board, a method for manufacturing the same, and a method for manufacturing a wiring board.

[0002] To achieve higher density and higher performance in semiconductor packages, mounting configurations have been proposed in which chips with different performance characteristics are mixed into a single package. For example, Patent Document 1 discloses a pretreatment method for via plating in which vias are formed on at least one metal layer and polyimide layer of a double-sided metal laminate in which metal layers are laminated on both sides of a polyimide film, and then a wet blasting method is used to remove metal burrs generated in the via formation process and to clean the inside of the holes (see claim 8 of Patent Document 1).

[0003] Japanese Patent Publication No. 2003-318519

[0004] Patent Document 1 discloses a technique for forming a seed layer by electroless plating after desmearing and then forming wiring. In recent years, semiconductor devices have been trending toward miniaturization, and wiring substrates are also required to be miniaturized. To form fine wiring on a wiring substrate, a semi-additive process is used, in which a photosensitive material is formed on the substrate material, and then a plating process is performed after exposure and development. However, due to the waviness of the substrate material such as glass cloth contained in the substrate, or the unevenness caused by variations in the thickness of the core material, exposure cannot be performed properly, and it is difficult to form fine wiring with a good yield. Furthermore, due to the above-mentioned unevenness, there is a problem that the yield of chip mounting on the formed circuit deteriorates. On the other hand, when forming fine wiring on a smooth surface, it is necessary to roughen the surface of the wiring substrate to increase the adhesion strength between the fine wiring and the wiring substrate interface through an anchoring effect.

[0005] This disclosure provides a component for a wiring board and a method for manufacturing the same, which are useful for manufacturing a wiring board having excellent flatness and excellent adhesion to a wiring layer. This disclosure also provides a method for manufacturing a wiring board using the above-mentioned component for a wiring board.

[0006] This disclosure finds that the problem of smoothness can be solved by setting the thickness of the resin composition coating the substrate to be thicker than the final design value in order to absorb the waviness of the substrate contained in the wiring board component or the unevenness caused by variations in the thickness of the core material, and then flattening the outermost surface after curing, for example by chemical mechanical polishing. On the other hand, regarding the problem of fine wiring formation, it has been found that the problem of adhesion of fine wiring can be solved by, for example, surface modification of the substrate surface using ultraviolet light.

[0007] This disclosure relates to the following: [1] A method for manufacturing a component for a wiring board, comprising: (a) preparing a first sheet comprising a base material and a first layer composed of a first resin composition and in which the base material is embedded; (b) heating a laminate while applying pressing force in the thickness direction of the laminate, which includes a second sheet composed of a second resin composition and the first sheet, and in which at least one of the outermost surfaces is formed by the second sheet; and (c) flattening the outermost surface after step (b) such that the average surface roughness Ra of the outermost surface of the laminate is 20 nm or less. [2] The method for manufacturing a component for a wiring board according to [1], wherein after step (b) and before step (c), the laminate has a shaving allowance provided on the outermost surface side, and the shaving allowance includes the second sheet. [3] The method for manufacturing a component for a wiring board according to [2], wherein the shaving allowance further includes a region of the first sheet that is in contact with the second sheet and is composed of the first resin composition. [4] A method for manufacturing a wiring board member according to [2] or [3], wherein the thickness of the material removed is 100 to 2000 μm. [5] (d): A method for manufacturing a wiring board member according to any one of [1] to [4], further comprising the step of forming a modified region on the outermost surface of the laminate by treating the outermost surface of the laminate with a surface modification treatment method after step (c), wherein the average surface roughness Ra of the outermost surface is 70 nm or less after step (d). [6] A wiring board member comprising a base material, a resin layer composed of a resin composition in which the base material is embedded, wherein the average surface roughness Ra of at least one of the outermost surfaces of the resin layer is 20 nm or less. [7] A wiring board member comprising a base material, a resin layer composed of a resin composition in which the base material is embedded, and a material removed provided on at least one of the outermost surfaces of the resin layer, wherein the thickness of the material removed is 100 to 2000 μm. [8] The wiring board member according to [6] or [7], wherein the base material is a woven fabric, the resin composition contains a thermosetting resin, and the wiring board member is a prepreg.A method for manufacturing a wiring board, comprising the steps of: forming a modified region on the surface of the resin layer of the wiring board member described in [9] [6] by treating the outermost surface of the resin layer with a surface modification treatment method; forming a seed layer including one or more metal layers on the surface of the resin layer by electroless plating; forming a resist on the seed layer having a pattern including openings for wiring formation in which the seed layer is exposed; forming the wiring on the seed layer exposed in the openings by electrolytic copper plating; removing the resist; and removing the portion of the seed layer that is not covered by the wiring. A method for manufacturing a wiring board, comprising the steps of: flattening the outermost surface of the resin layer of the wiring board member described in

[10] and [7] so that the average surface roughness Ra is 20 nm or less; forming a modified region on the surface of the resin layer by treating the flattened outermost surface with a surface modification treatment method; forming a seed layer including one or more metal layers on the surface of the resin layer by electroless plating; forming a resist on the seed layer having a pattern including openings for wiring formation in which the seed layer is exposed; forming the wiring on the seed layer exposed in the openings by electrolytic copper plating; removing the resist; and removing the portion of the seed layer that is not covered by the wiring.

[11] The method for manufacturing a wiring board according to [9] or

[10] , wherein the treatment method is at least one treatment method selected from the group consisting of ultraviolet irradiation, electron beam irradiation, ozone water treatment, and corona discharge treatment.

[12] The method for manufacturing a wiring board according to [9] or

[10] , wherein the treatment method is ultraviolet irradiation.

[13] The method for manufacturing a wiring board according to [9] or

[10] , wherein the processing method is ultraviolet irradiation using an incoherent light source.

[0008] This disclosure provides a component for a wiring board and a method for manufacturing the same, which are useful for manufacturing a wiring board having excellent flatness and excellent adhesion to a wiring layer. Furthermore, this disclosure provides a method for manufacturing a wiring board using the above-mentioned component for a wiring board.

[0009] Figure 1 is a schematic cross-sectional view showing one embodiment of a wiring board component according to the present disclosure. Figures 2(a) and 2(b) are schematic cross-sectional views showing the process of manufacturing the wiring board component shown in Figure 1. Figure 3 is a schematic cross-sectional view showing another embodiment of the wiring board component according to the present disclosure. Figures 4(a) to 4(c) are schematic cross-sectional views showing an example of a process for manufacturing a wiring board from a wiring board component. Figures 5(a) to 5(c) are schematic cross-sectional views showing an example of a process for manufacturing a wiring board from a wiring board component.

[0010] Embodiments of this disclosure will be described in detail below with reference to the drawings. In the following description, the same or equivalent parts will be denoted by the same reference numerals, and redundant descriptions will be omitted. Furthermore, unless otherwise specified, positional relationships such as top, bottom, left, and right will be based on the positional relationships shown in the drawings. Moreover, the dimensional ratios in the drawings are not limited to those shown.

[0011] Where terms such as "left," "right," "front," "back," "top," "bottom," "upper," and "downward" are used in this specification, they are for illustrative purposes only and do not necessarily imply that the relative position is permanent. Furthermore, the term "layer" includes not only structures formed on the entire surface when viewed as a plan view, but also structures formed on only a portion of it.

[0012] <Component for Wiring Board> Figure 1 is a schematic cross-sectional view showing a component for a wiring board according to this embodiment, and shows the layer structure of the wiring board component 10. The wiring board component 10 comprises a base material 1, a resin layer 3 in which the base material 1 is embedded, and a machining allowance 5 provided on one of the outermost surfaces 3a of the resin layer 3. The resin layer 3 is made of a resin composition. The machining allowance 5 is also made of a resin composition. The wiring board component 10 may be, for example, a prepreg or an organic core material.

[0013] (Base Material) As the base material 1, well-known materials used in laminates for various electrical insulating materials can be used. Examples of materials include inorganic fibers such as E-glass, D-glass, S-glass, and Q-glass, organic fibers such as polyimide, polyester, and tetrafluoroethylene, and mixtures thereof. These base materials can be in the form of, for example, woven fabric, nonwoven fabric, rawhide, chopped strand mat, and surfacing mat. The material and shape are selected according to the application or performance of the component, and if necessary, one or more materials and shapes can be combined. The thickness of the base material 1 is not particularly limited, for example, about 0.03 to 0.5 mm. As the base material 1, those that have been surface-treated with a silane coupling agent or the like, or those that have been mechanically opened, are preferable in terms of heat resistance, moisture resistance, and processability.

[0014] (Resin Composition) The resin layer 3 is composed of a resin composition. The resin composition contains, for example, a thermosetting resin 3b and an inorganic filler 3c. The resin composition may undergo a semi-cured (B stage) state and then become cured (C stage) after curing treatment.

[0015] The resin composition contains, for example, the following compounds: (a) a maleimide compound having at least two N-substituted maleimide groups in one molecular structure; (b) a silicone compound having an epoxy group in its molecular structure; (c) a compound having a phenolic hydroxyl group.

[0016] Examples of the compounds in (a) above include bis(4-maleimidophenyl)methane, polyphenylmethanemaleimide, bis(4-maleimidophenyl) ether, bis(4-maleimidophenyl) sulfone, 3,3'-dimethyl-5,5'-diethyl-4,4'-diphenylmethanebismaleimide, 4-methyl-1,3-phenylenebismaleimide, m-phenylenebismaleimide, 2,2'-bis(4-(4-maleimidophenoxy)phenyl)propane, and among these, those with a high reaction rate and higher heat resistance Bis(4-maleimidophenyl)methane, bis(4-maleimidophenyl)sulfone, 3,3'-dimethyl-5,5'-diethyl-4,4'-diphenylmethanebismaleimide, and 2,2'-bis(4-(4-maleimidophenoxy)phenyl)propane are preferred, and 3,3'-dimethyl-5,5'-diethyl-4,4'-diphenylmethanebismaleimide and bis(4-maleimidophenyl)methane are more preferred in terms of solubility in solvents, with bis(4-maleimidophenyl)methane being particularly preferred in terms of low cost.

[0017] As the compound in (b) above, commercially available products can be used, for example, "X-22-163" (functional group equivalent 200), "KF-105" (functional group equivalent 490), "X-22-163A" (functional group equivalent 1000), "X-22-163B" (functional group equivalent 1750), "X-22-163C" (functional group equivalent 2700), which have epoxy groups at both ends, "X-22-169AS" (functional group equivalent 500), "X-22-169B" (functional group equivalent 1700), which have alicyclic epoxy groups at both ends, "X-22-1730X" (functional group equivalent 4500), which has an epoxy group at one end, and "X" which has epoxy groups at the side chain and both ends. Examples include "X-22-9002" (functional group equivalent 5000), "X-22-343" (functional group equivalent 525), "KF-101" (functional group equivalent 350), "KF-1001" (functional group equivalent 3500), "X-22-2000" (functional group equivalent 620), "X-22-4741" (functional group equivalent 2500), "KF-1002" (functional group equivalent 4300), "X-22-2046" (functional group equivalent 600), and "KF-102" (functional group equivalent 3600), which have alicyclic epoxy resins in their side chains. These can be used individually, in combination of two or more types, or mixed with various epoxy resins. Among these, "X-22-163A," "X-22-163B," "X-22-343," "X-22-9002," and "KF-101" are preferred in terms of heat resistance, "X-22-163A" and "X-22-163B" are more preferred, and "X-22-163B" is particularly preferred in terms of low thermal expansion coefficient. (All are product names of Shin-Etsu Chemical Co., Ltd.)

[0018] The content of compound (b) in the resin composition is preferably 20 to 200 parts by mass, and more preferably 50 to 100 parts by mass, per 100 parts by mass of the solid content of compound (a). Setting the content to 20 parts by mass or more prevents a decrease in low thermal expansion, and setting it to 200 parts by mass or less prevents a decrease in moldability.

[0019] Examples of the compounds in (c) above include bisphenol A, bisphenol F, bisphenol S, 4,4'-biphenylphenol, tetramethylbisphenol A, dimethylbisphenol A, tetramethylbisphenol F, dimethylbisphenol F, tetramethylbisphenol S, dimethylbisphenol S, tetramethyl 4,4'-biphenol, dimethyl-4,4'-biphenylphenol, 1-(4-hydroxyphenyl)-2-[4-(1,1'-bis-(4-hydroxyphenyl)ethyl)phenyl]propane, 2,2'-methylene-bis(4-methyl-6-tert-butylphenol), 4,4'-butylidene-bis(3-methyl-6-tert-butylphenol), trishydrox Examples of novolac resins include those made from various phenols such as cyphenylmethane, resorcinol, hydroquinone, pyrogallol, phenols having a diisopropolide skeleton, phenols having a fluorene skeleton such as 1,1'-di-4-hydroxyphenylfluorene, phenolized polybutadiene, phenols, cresols, ethylphenols, butylphenols, octylphenols, bisphenol A, bisphenol F, bisphenol S, naphthols, xylylene skeleton-containing phenol novolac resins, dicyclopentadiene skeleton-containing phenol novolac resins, biphenyl skeleton-containing phenol novolac resins, and fluorene skeleton-containing phenol novolac resins.

[0020] The compound in (c) above may have an amino group in its molecule, and examples include m-aminophenol, p-aminophenol, o-aminophenol, p-aminobenzoic acid, m-aminobenzoic acid, o-aminobenzoic acid, o-aminobenzenesulfonic acid, m-aminobenzenesulfonic acid, p-aminobenzenesulfonic acid, 3,5-dihydroxyaniline, 3,5-dicarboxyaniline, etc. These may be used individually or in combination of two or more. Among these, m-aminophenol, p-aminophenol, o-aminophenol, p-aminobenzoic acid, m-aminobenzoic acid, and 3,5-dihydroxyaniline are preferred in terms of solubility and synthesis yield, m-aminophenol and p-aminophenol are more preferred in terms of heat resistance, and p-aminophenol is particularly preferred in terms of low thermal expansion.

[0021] In the resin composition, the compound (a) and the compound (c) can be reacted in advance by stirring for 0.1 to 10 hours while heating or maintaining the temperature as necessary. In this case, the compound (c) is not particularly limited as long as it is a compound having an amino group in its molecule, but p-aminophenol is preferred from the viewpoint of low thermal expansion. Here, when a compound having an amino group in its molecule is used as component (c), the ratio of component (c) to -NH ２ It is desirable that the equivalent ratio of the maleimide group equivalent of the compound in (a) above to the equivalent amount in terms of groups be within the range shown in the following formula: 2.0 ≤ (maleimide group equivalent) / (-NH ２ (Equivalent amount in terms of base) ≤ 10.0 By setting this equivalent ratio to 2.0 or higher, gelation does not occur and the heat resistance of the thermosetting resin does not decrease. By setting it to 10.0 or lower, solubility in the solvent does not become insufficient and the heat resistance of the thermosetting resin does not decrease.

[0022] The organic solvent used in this reaction is not particularly limited, but examples include alcohol-based solvents such as ethanol, propanol, butanol, methyl cellosolve, butyl cellosolve, and propylene glycol monomethyl ether; ketone-based solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; ether-based solvents such as tetrahydrofuran; aromatic solvents such as toluene, xylene, and mesitylene; N-atom-containing solvents such as dimethylformamide, dimethylacetamide, and N-methylpyrrolidone; and S-atom-containing solvents such as dimethyl sulfoxide. One or more of these can be used in combination. Among these, cyclohexanone, propylene glycol monomethyl ether, and methyl cellosolve are preferred from the viewpoint of solubility, cyclohexanone and propylene glycol monomethyl ether are more preferred from the viewpoint of low toxicity, and propylene glycol monomethyl ether is particularly preferred because it is highly volatile and does not remain as a residual solvent during the production of the prepreg.

[0023] The amount of organic solvent used is preferably 10 to 1000 parts by mass, more preferably 100 to 500 parts by mass, and particularly preferably 200 to 500 parts by mass, based on 100 parts by mass of the total sum of the compounds in (a) and (c) above. By using 10 parts by mass or more of organic solvent, insufficient solubility is avoided, and by using 1000 parts by mass or less, the synthesis does not require a long time. A reaction catalyst can be used in this reaction as needed and is not particularly limited. Examples of reaction catalysts include amines such as triethylamine, pyridine, and tributylamine, imidazoles such as methylimidazole and phenylimidazole, and phosphorus-based catalysts such as triphenylphosphine, and one or more of these can be used in combination.

[0024] When the compound (a) and the compound (c) described above are reacted in an organic solvent, the reaction temperature is preferably 70 to 150°C, and more preferably 100 to 130°C. The reaction time is preferably 0.1 to 10 hours, and more preferably 1 to 6 hours.

[0025] It is preferable to use a curing accelerator in the above resin composition to improve heat resistance, flame retardancy or copper foil adhesion. Examples of the curing accelerator include imidazoles and derivatives thereof, tertiary amines, quaternary ammonium salts, and the like. Among these, imidazoles and derivatives thereof are preferable from the viewpoints of heat resistance, flame retardancy and copper foil adhesion. Further, a compound substituted with an isocyanate resin represented by the following formula (1) and a compound in which an imidazole group represented by the following formula (2) is substituted with an epoxy resin are more preferable because they are excellent in curing moldability at a relatively low temperature of 200°C or lower and the storage stability of varnish or prepreg over time, and a compound represented by the following formula (3) or (4) is particularly preferable because it may be used in a small blending amount and is inexpensive commercially.

[0026] In the formula, R １ , R ２ , R ３ , R ４ each independently represent a hydrogen atom, an aliphatic hydrocarbon group having 1 to 5 carbon atoms, or a phenyl group, and D is a residue of an isocyanate resin such as an alkylene group or an aromatic hydrocarbon group.

[0027] In the formula, R １ , R ２ , R ３ , R ４ each independently represent a hydrogen atom, an aliphatic hydrocarbon group having 1 to 5 carbon atoms, or a phenyl group, and B is any one of a short bond, an alkylene group, an alkylidene group, an ether group, and a sulfonyl group.

[0028]

[0029]

[0030] The amount of curing accelerator used is preferably 0.1 to 10 parts by mass, more preferably 0.1 to 5 parts by mass, and particularly preferably 0.1 to 1 part by mass, based on 100 parts by mass of the total amount of the compounds (a) to (c) in terms of solid content. By using 0.1 parts by mass or more of the curing accelerator, a decrease in heat resistance, flame retardancy, or copper foil adhesion can be prevented, and by using 10 parts by mass or less, a decrease in heat resistance, long-term stability, and press formability can be prevented.

[0031] The above resin composition may optionally contain inorganic fillers, examples of which include silica, alumina, talc, mica, kaolin, aluminum hydroxide, boehmite, magnesium hydroxide, zinc borate, zinc stannate, zinc oxide, titanium oxide, boron nitride, calcium carbonate, barium sulfate, aluminum borate, potassium titanate, glass powders such as E-glass, T-glass, and D-glass, and hollow glass beads. One or more of these can be used in combination. Among these, silica is particularly preferred in terms of dielectric properties, heat resistance, and low thermal expansion. Examples of silica include precipitated silica, which is produced by a wet process and has a high water content, and dry-process silica, which is produced by a dry process and contains almost no bound water. Dry-process silica can be further classified into crushed silica, fumed silica, and molten spherical silica depending on the manufacturing method. Among these, molten spherical silica is preferred due to its low thermal expansion and high fluidity when filled into resin.

[0032] When molten spherical silica is used as an inorganic filler, its average particle size is preferably 0.1 to 10 μm, and more preferably 0.3 to 8 μm. By making the average particle size of the molten spherical silica 0.1 μm or more, good fluidity can be maintained when it is densely packed into the resin, and by making it 10 μm or less, the probability of coarse particles being mixed in can be reduced, and the occurrence of defects caused by coarse particles can be suppressed. Here, the average particle size is the particle size at the point corresponding to exactly 50% of the volume when the cumulative frequency distribution curve by particle size is calculated with the total volume of the particles as 100%, and can be measured with a particle size distribution analyzer using laser diffraction scattering or the like.

[0033] The inorganic filler content is preferably 10 to 70 parts by mass, and more preferably 30 to 55 parts by mass, per 100 parts by mass of the total amount of the compounds (a) to (c) in terms of solid content. By keeping the content within this range, the moldability and low thermal expansion properties of the resin composition can be maintained well.

[0034] The above resin composition may contain other thermosetting resins. Examples of such thermosetting resins include epoxy resins, phenolic resins, unsaturated imide resins, cyanate resins, isocyanate resins, benzoxazine resins, oxetane resins, amino resins, unsaturated polyester resins, allyl resins, dicyclopentadiene resins, silicone resins, triazine resins, melamine resins, and others. One or more of these can be used in combination. Among these, epoxy resins and cyanate resins are preferred from the viewpoint of moldability and electrical insulation.

[0035] Examples of epoxy resins include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, bisphenol A novolac type epoxy resin, bisphenol F novolac type epoxy resin, stilbene type epoxy resin, triazine skeleton-containing epoxy resin, fluorene skeleton-containing epoxy resin, triphenolphenolmethane type epoxy resin, biphenyl type epoxy resin, xylylene type epoxy resin, biphenyl aralkyl type epoxy resin, naphthalene type epoxy resin, dicyclopentadiene type epoxy resin, alicyclic epoxy resin, diglycidyl ether compounds of polycyclic aromatics such as polyfunctional phenols and anthracenes, and phosphorus-containing epoxy resins obtained by introducing phosphorus compounds into these. Among these, biphenyl aralkyl type epoxy resin and naphthalene type epoxy resin are preferred in terms of heat resistance and flame retardancy. These can be used individually or in mixtures of two or more types.

[0036] Examples of cyanate resins include bisphenol-type cyanate resins such as novolac-type cyanate resin, bisphenol A-type cyanate resin, bisphenol E-type cyanate resin, and tetramethylbisphenol F-type cyanate resin, as well as prepolymers obtained by partially triazinating these cyanate resins. Among these, novolac-type cyanate resin is preferred from the viewpoints of heat resistance and flame retardancy. These may be used alone or in a mixture of two or more thereof.

[0037] The resin composition may optionally contain known thermoplastic resins, elastomers, flame retardants, organic fillers, and the like. Examples of thermoplastic resins include tetrafluoroethylene, polyethylene, polypropylene, polystyrene, polyphenylene ether resins, phenoxy resins, polycarbonate resins, polyester resins, polyamide resins, polyimide resins, xylene resins, petroleum resins, and silicone resins. Examples of elastomers include polybutadiene, acrylonitrile, epoxy-modified polybutadiene, maleic anhydride-modified polybutadiene, phenol-modified polybutadiene, and carboxy-modified acrylonitrile. Examples of flame retardants include halogen-containing flame retardants containing bromine or chlorine; phosphorus-based flame retardants such as triphenyl phosphate, tricresyl phosphate, tris(dichloropropyl) phosphate, phosphate ester compounds, and red phosphorus; nitrogen-based flame retardants such as guanidine sulfamate, melamine sulfate, melamine polyphosphate, and melamine cyanurate; phosphazene-based flame retardants such as cyclophosphazene and polyphosphazene; and inorganic flame retardants such as antimony trioxide.

[0038] The resin composition may optionally contain additives such as ultraviolet absorbers, antioxidants, photopolymerization initiators, fluorescent whitening agents, and adhesion improvers, and there is no particular limitation thereto. Examples of these additives include ultraviolet absorbers such as benzotriazole-based absorbers; antioxidants such as hindered phenol-based antioxidants and styrenated phenol; photopolymerization initiators such as benzophenones, benzyl ketals, and thioxanthone-based initiators; fluorescent whitening agents such as stilbene derivatives; and adhesion improvers such as urea compounds like urea silane, and silane coupling agents.

[0039] (Margin for grinding) The margin for grinding 5 is a portion that is ground after curing, for example, to eliminate unevenness caused by warping of the base material 1 or variations in the thickness of the core material. It should be noted that when the base material 1 is a woven fabric, warping caused by the weaving of the woven fabric is likely to occur. The margin for grinding 5 is provided on at least one outermost surface 3a of the resin layer 3. The thickness of the margin for grinding 5 depends on the size of the wiring board member 10, and is, for example, 100 to 2000 µm, and may also be 500 to 2000 µm or 1000 to 1500 µm. When the thickness of the margin for grinding 5 is 100 µm or more, grinding the margin for grinding 5 can sufficiently eliminate the aforementioned unevenness; on the other hand, when the thickness is 2000 µm or less, excessive thickening of the wiring board member 10 can be suppressed.

[0040] The margin for grinding 5 is composed of a resin composition. The resin composition constituting the margin for grinding 5 may be the same as the resin composition constituting the resin layer 3. However, since the margin for grinding 5 is expected to be ground, it preferably does not contain an inorganic filler. If the margin for grinding 5 contains an inorganic filler, the inorganic filler exposed on the surface may fall off after grinding. Since the margin for grinding 5 does not contain an inorganic filler, falling off of the inorganic filler after grinding can be prevented in advance, and the outermost surface of the wiring board member 10 can maintain a highly flat state.

[0041] <Method for Manufacturing Wiring Board Member> The wiring board member 10 shown in FIG. 1 is manufactured through the following steps. (a): A step of preparing a base material 1, and a resin layer 3 (a first layer and a first sheet) which is composed of a first resin composition and in which the base material 1 is embedded (see FIG. 2(a)). (b): A step of heating the laminate 10P while applying a pressing force in the thickness direction of the laminate 10P, wherein the laminate 10P comprises the margin for grinding 5 (a second sheet) composed of a second resin composition and the resin layer 3, and the outermost surface of the laminate 10P is constituted by the margin for grinding 5 (see FIG. 2(b))

[0042] The resin layer 3 can be produced through a step of impregnating or coating the base material 1 with a varnish obtained by diluting the first resin composition with a solvent. The margin for grinding 5 may be produced through a step of coating a varnish obtained by diluting the second resin composition with a solvent onto a support film, or may be produced through a step of coating the aforementioned varnish onto the surface of the resin layer 3.

[0043] For example, a laminate (not shown) may be made by stacking 1 to 20 resin layers 3, placing a machining allowance 5 on one or both sides thereof, and further placing a metal foil such as copper or aluminum on the surface of the machining allowance 5. For example, a multi-stage press, multi-stage vacuum press, continuous molding, or autoclave molding machine may be used, with a temperature of 100 to 250°C and a pressure of 2 to 100 kg / cm². ２ By molding under conditions of heating time of 0.1 to 5 hours, a laminate having a material removal allowance 5 can be obtained.

[0044] Figure 3 is a schematic cross-sectional view showing a wiring board member 20 obtained by flattening the surface of a wiring board member 10 by grinding the material allowance 5. That is, the figure shows a wiring board member 20 obtained by performing the following step (c) after step (b) above. (c): A step to flatten the outermost surface of the wiring board member 10 by grinding the material allowance 5 so that the average surface roughness Ra of the outermost surface is 20 nm or less.

[0045] Prior to grinding the material to be removed 5, it is preferable to thoroughly harden the entire wiring board member 10, including the material to be removed 5. That is, it is preferable to heat the wiring board member 10 at a temperature of 100 to 200°C for 1 to 30 minutes. After that, by polishing the material to be removed 5 to flatten the outermost surface, a wiring board member 20 with an average surface roughness Ra of 20 nm or less on the outermost surface 20a is obtained. An average surface roughness Ra of 20 nm or less on the outermost surface 20a makes it possible to form fine wiring with a good yield. The average surface roughness Ra may be 10 nm or less or 1 nm or less. For example, even if warping occurs in the wiring board member 10 due to the heat treatment, the warping can be eliminated by grinding the material to be removed 5.

[0046] Examples of polishing methods include mechanical polishing and chemical mechanical polishing (CMP). It is preferable that the substrate 1 contained in the resin composition is not exposed on the surface after grinding. If a laminate with an average surface roughness Ra of 20 nm or less on the outermost surface is obtained by the above-described press working, grinding of the material to be removed 5 may not be necessary.

[0047] <Method for Manufacturing a Wiring Board> The method for manufacturing a wiring board will be described with reference to Figures 4(a) to 4(c) and Figures 5(a) to 5(c). A wiring board 30 can be obtained from a wiring board member 20 by following the steps below. Note that the resin layer 5a shown in Figure 4(a) is a layer formed by grinding the surface of the material to be removed 5, and consists of the portion that remains without being removed by grinding the material to be removed 5. (1) A step of forming a modified region Rm on the surface (outermost surface 20a) of the resin layer 5a of the wiring board member 20 by processing the surface of the resin layer 5a with a surface modification method (see Figure 4(a)). (2) A step of forming a seed layer 6 containing one or more metal layers on the modified surface of the resin layer 5a by electroless plating (see Figure 4(b)). (3) A step of forming a resist 7 on the seed layer 6 that has a pattern including wiring formation openings 7a in which the seed layer 6 is exposed (see Figure 4(c)). (4) A step of forming wiring 8 on the seed layer 6 exposed in the opening 7a by electrolytic copper plating (see Figure 5(a)). (5) A step of removing the resist 7 (see Figure 5(b)). (6) A step of removing the portion of the seed layer 6 that is not covered by the wiring 8 (see Figure 5(c)).

[0048] Prior to carrying out step (1) above, through-holes or blind via holes may be formed in the wiring board component 20 by drilling or laser processing. After that, a multilayer printed wiring board can be manufactured by going through steps (3) and (4) above.

[0049] In step (1) above, by forming a modified region on the surface of the resin layer 5a, the adhesion between the resin layer and the seed layer can be improved while maintaining a relatively low surface roughness. The modified region may contain multiple fine pores communicating with the resin layer. During the process of forming the seed layer by electroless plating, some of the metal forming the seed layer enters the pores in the modified region, and as a result, the adhesion between the seed layer and the resin layer is improved. The formation of pores can be confirmed, for example, by observing the cross-section of the resin layer with a scanning transmission electron microscope. If the entire material to be ground 5 is removed and the outermost surface of the wiring board component is composed of the resin layer 3, the modified region should be formed on this outermost surface.

[0050] The treatment method for forming the modified region may be at least one treatment method selected from the group consisting of electron beam irradiation, ozone water treatment, and corona discharge treatment, or it may be ultraviolet irradiation. Ultraviolet irradiation has the advantages of not requiring vacuum equipment and not generating waste liquid. Ultraviolet irradiation may be performed using an incoherent light source. Compared to coherent light sources such as laser light sources, incoherent light sources are advantageous in that they can efficiently irradiate a wide area of ​​the resin layer with ultraviolet light. Examples of incoherent light sources include high-pressure mercury lamps, low-pressure mercury lamps, and excimer lamps. The incoherent light source may be a low-pressure mercury lamp or an excimer lamp that has a large activation effect.

[0051] The treatment for forming the modified region (e.g., ultraviolet irradiation) can be carried out, for example, in air or an oxygen atmosphere. In the treatment for forming the modified region, the temperature of the resin layer may be 25°C to 100°C, 40°C to 100°C, or 60°C to 100°C. Higher temperatures can lead to more efficient formation of the modified region.

[0052] The surface of the resin layer including the modified region may have an average surface roughness Ra of 70 nm or less. A low average surface roughness Ra makes it less likely for defects in fine wiring to occur. Because the modified region is formed, even with a low average surface roughness Ra, the adhesion between the resin layer and the seed layer can be sufficiently improved.

[0053] The modified region may be formed to a depth of 50 nm or more from the surface of the resin layer. The deeper the modified region is formed, the more pronounced the effect of improved adhesion is likely to be. The depth of the modified region from the surface may be 200 nm or less.

[0054] According to the above embodiment, a wiring board component and a method for manufacturing the same are provided, which are useful for manufacturing a wiring board having excellent flatness and excellent adhesion to the wiring layer. Furthermore, according to the above embodiment, a method for manufacturing a wiring board using the above wiring board component is provided.

[0055] The wiring board manufactured by the above method comprises a resin layer 5a having a surface with an average surface roughness Ra of 20 nm or less, and a wiring layer formed on the surface of the resin layer 5a. The wiring layer is composed of a part of the seed layer 6 and wiring 8. A semiconductor package can be manufactured using this wiring board. The semiconductor package comprises a wiring board and a semiconductor chip mounted on the wiring board. The semiconductor package may have multiple semiconductor chips mounted on it, and the multiple semiconductor chips may have different performance characteristics. The semiconductor chip may be flip-chip mounted on the wiring board.

[0056] 1...Substrate, 3...Resin layer (first layer and first sheet), 3a...Outer surface, 3b...Thermosetting resin, 3c...Inorganic filler, 5...Machining allowance (second sheet), 10, 20...Components for wiring boards, 10P...Laminate, 20a...Outer surface.

Claims

1. A method for manufacturing a component for a wiring board, comprising: (a) preparing a first sheet comprising a base material and a first layer composed of a first resin composition and in which the base material is embedded; (b) heating a laminate while applying pressing force in the thickness direction of the laminate, which comprises a second sheet composed of a second resin composition and the first sheet, and in which at least one of the outermost surfaces is formed by the second sheet; and (c) flattening the outermost surface after step (b) such that the average surface roughness Ra of the outermost surface of the laminate is 20 nm or less.

2. The method for manufacturing a wiring board member according to claim 1, wherein, after step (b) and before step (c), the laminate has a material removal allowance provided on the outermost surface side, and the material removal allowance includes the second sheet.

3. The method for manufacturing a wiring board member according to claim 2, wherein the material to be removed further includes a region of the first sheet that is in contact with the second sheet and is composed of the first resin composition.

4. The method for manufacturing a wiring board component according to claim 2, wherein the thickness of the material to be removed is 100 to 2000 μm.

5. (d): The method for manufacturing a wiring board component according to claim 1, further comprising the step of forming a modified region on the outermost surface of the laminate by treating the outermost surface of the laminate with a surface modification treatment method after step (c), wherein the average surface roughness Ra of the outermost surface after step (d) is 70 nm or less.

6. A component for a wiring board, comprising a base material and a resin layer composed of a resin composition in which the base material is embedded, wherein the average surface roughness Ra of at least one of the outermost surfaces of the resin layer is 20 nm or less.

7. A component for a wiring board, comprising: a base material; a resin layer composed of a resin composition and in which the base material is embedded; and a machining allowance provided on at least one outermost surface side of the resin layer, wherein the thickness of the machining allowance is 100 to 2000 μm.

8. The wiring board member according to claim 6 or 7, wherein the base material is a woven fabric, the resin composition contains a thermosetting resin, and the wiring board member is a prepreg.

9. A method for manufacturing a wiring board, comprising the steps of: forming a modified region on the surface of the resin layer of the wiring board member according to claim 6 by treating the outermost surface of the resin layer with a surface modification treatment method; forming a seed layer including one or more metal layers on the surface of the resin layer by electroless plating; forming a resist on the seed layer having a pattern including openings for wiring formation in which the seed layer is exposed; forming the wiring on the seed layer exposed in the openings by electrolytic copper plating; removing the resist; and removing the portion of the seed layer that is not covered by the wiring.

10. A method for manufacturing a wiring board, comprising the steps of: flattening the outermost surface of the resin layer of the wiring board member according to claim 7 so that the average surface roughness Ra is 20 nm or less; forming a modified region on the surface of the resin layer by treating the flattened outermost surface with a surface modification treatment method; forming a seed layer including one or more metal layers on the surface of the resin layer by electroless plating; forming a resist on the seed layer having a pattern including openings for wiring formation in which the seed layer is exposed; forming the wiring on the seed layer exposed in the openings by electrolytic copper plating; removing the resist; and removing the portion of the seed layer that is not covered by the wiring.

11. The method for manufacturing a wiring board according to claim 9 or 10, wherein the processing method is at least one processing method selected from the group consisting of ultraviolet irradiation, electron beam irradiation, ozone water treatment, and corona discharge treatment.

12. The method for manufacturing a wiring board according to claim 9 or 10, wherein the processing method is ultraviolet irradiation.

13. The method for manufacturing a wiring board according to claim 9 or 10, wherein the processing method is ultraviolet irradiation using an incoherent light source.

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