Method for manufacturing metal-clad laminate, metal-clad laminate, printed wiring board, semiconductor package, support for forming coreless substrate, and support for forming semiconductor rewiring layer

Abstract

Provided are a metal-clad laminate having excellent plate thickness accuracy, a method for manufacturing the same, a semiconductor package, a support for forming a coreless substrate, and a support for forming a semiconductor rewiring layer. A method for producing the metal-clad laminate comprises: (1) a step for polishing at least one surface of a cured product of a prepreg comprising a thermosetting resin composition and a base material; and (2-1) a step for forming a metal-clad laminate by laminating a metal foil on the surface polished in step (1), or (2-2) a step for forming a metal-clad laminate on the surface polished in step (1) such that a thermosetting resin film is on the surface side polished in step (1). And a step for forming a metal-clad laminate by laminating a metal foil and a thermosetting resin film, or laminating a thermosetting resin film to which a metal foil is attached.

Description

[0001] The present application is a divisional application of PCT / JP2019 / 000741 application with application number: 201980088653.0, application date: January 11, 2019, and invention name: "Method for manufacturing metal-clad laminate, metal-clad laminate, printed wiring board and semiconductor package, as well as support body for forming coreless substrate and support body for forming semiconductor redistribution layer". Technical Field

[0002] The present invention relates to a method for manufacturing a metal-clad laminate, a metal-clad laminate, a printed wiring board, a semiconductor package, a support for forming a coreless substrate, and a support for forming a semiconductor redistribution layer. Background Art

[0003] In recent years, as electronic devices have become increasingly dense, miniaturized, lightweight, and multifunctional, demands for higher density and reliability have also emerged for printed wiring boards and semiconductor packages used in LSIs (Large Scale Integration). Consequently, the need for improved thickness accuracy in metal-clad laminates is becoming increasingly stringent.

[0004] Metal-clad laminates, formed by laminating multiple prepreg sheets sandwiched between metal foils through press molding, are used as core substrates for printed wiring boards (see, for example, paragraph

[0057] of Patent Document 1). However, due to the influence of base materials such as glass cloth within the prepreg, surface undulations may occur after press molding. While this level of surface undulation has traditionally been tolerated, there is a growing trend toward achieving even higher levels of thickness accuracy in metal-clad laminates to ensure greater density and reliability. Consequently, there is a need to address the reduced thickness accuracy caused by this surface undulation.

[0005] In addition, the plate thickness accuracy tends to depend on the fluidity of the resin composition. Figure 7 As shown, the resin composition layer at the ends of metal-clad laminates (so-called pressed sheets before being cut to a predetermined size) obtained by press forming or other lamination processes is generally thinner. Therefore, from the perspective of plate thickness accuracy, the thinned portions of the resin composition layer must be discarded. Meanwhile, methods are known for reducing the fluidity of the resin composition by adding a high level of inorganic filler, but these methods have limited effects on improving plate thickness accuracy, and when high levels of inorganic filler are required, a significant decrease in workability, such as drill workability, is unavoidable.

[0006] Prior art literature

[0007] Patent Literature

[0008] Patent Document 1: Japanese Patent Application Laid-Open No. 2016-056371 Summary of the Invention

[0009] Problems to be solved by the invention

[0010] Therefore, the present invention aims to provide a metal-clad laminate having excellent thickness accuracy and a method for manufacturing the same. Furthermore, the present invention aims to provide a printed wiring board having a circuit formed on the metal-clad laminate, a semiconductor package having a semiconductor element mounted on the printed wiring board, and a support for forming a coreless substrate and a support for forming a semiconductor redistribution layer, each including the metal-clad laminate.

[0011] Means for solving problems

[0012] The present inventors have conducted intensive research to address the above-mentioned issues and have discovered that polishing at least one surface of a cured prepreg obtained by etching away the metal foil of a press-molded metal-clad laminate, for example, can solve the above-mentioned problems. This has led to the completion of the present invention. The present invention has been completed based on this finding.

[0013] The present invention relates to the following [1] to

[15] .

[0014] [1] A method for manufacturing a metal-clad laminate, comprising:

[0015] (1) a step of polishing at least one surface of a cured product of a prepreg comprising a thermosetting resin composition and a base material;

[0016] (2-1) A step of laminating a metal foil on the surface polished in the above step (1) to form a metal-clad laminate.

[0017] [2] A method for manufacturing a metal-clad laminate, comprising:

[0018] (1) a step of polishing at least one surface of a cured product of a prepreg comprising a thermosetting resin composition and a base material;

[0019] (2-2) A step of forming a metal-clad laminate by laminating a metal foil and a thermosetting resin film, or laminating a thermosetting resin film with a metal foil on the surface polished in the step (1), with the thermosetting resin film facing the polished surface.

[0020] [3] The method for producing a metal-clad laminate according to [1] or [2] above, wherein in the step (1), both surfaces of the cured prepreg are polished.

[0021] [4] The method for producing a metal-clad laminate according to any one of [1] to [3] above, wherein the thickness of the cured product of the prepreg is made substantially uniform by the grinding in the step (1).

[0022] [5] The method for producing a metal-clad laminate according to any one of [1] to [4] above, wherein the cured product of the prepreg is obtained by etching away the metal foil of the metal-clad laminate whose surface inside the cured product has not been polished.

[0023] [6] A method for manufacturing a metal-clad laminate according to any one of [1] to [5] above, wherein the dimensions of the largest surface of the cured product of the prepreg are 200 mm to 1300 mm in length and 200 mm to 1300 mm in width, and the thickness of at least a portion within 70 mm from the end of the cured product of the prepreg is thinner than the thickness of the central portion of the cured product.

[0024] [7] The method for producing a metal-clad laminate according to any one of [1] to [6] above, wherein in the step (1), the entire surface is polished until the thickness matches the thinnest portion of the cured prepreg.

[0025] [8] A method for manufacturing a metal-clad laminate according to any one of [1] to [7] above, wherein in the step (1), polishing is performed by a method selected from the group consisting of: (i) CMP (Chemical Mechanical Polishing); (ii) mechanical polishing such as flying shearing, grinding, sandblasting, belt grinding, and scrub grinding; and (iii) chemical polishing using persulfate, a hydrogen peroxide-sulfuric acid mixture, an inorganic acid, an organic acid, or the like.

[0026] [9] The method for producing a metal-clad laminate according to any one of [1] to [8] above, wherein the difference between the maximum and minimum thicknesses of the obtained metal-clad laminate is 20 μm or less.

[0027]

[10] A metal-clad laminate obtained by the production method described in any one of [1] to [9] above.

[0028]

[11] A metal-clad laminate comprising: (a) a cured product which is a cured product of a prepreg comprising a thermosetting resin composition and a substrate, wherein at least one surface of the cured product has been polished; (b) a thermosetting resin composition layer which does not include a substrate; and (c) a metal foil.

[0029]

[12] A printed wiring board comprising the metal-clad laminate described in

[10] or

[11] .

[0030]

[13] A semiconductor package comprising a semiconductor element mounted on the printed wiring board described in

[12] .

[0031]

[14] A support for forming a coreless substrate, comprising the metal-clad laminate described in

[10] or

[11] .

[0032]

[15] A support for forming a semiconductor redistribution layer, comprising the metal-clad laminate described in

[10] or

[11] .

[0033] Effects of the Invention

[0034] The present invention can provide a metal-clad laminate having excellent thickness accuracy and a method for manufacturing the same. Furthermore, it can provide a printed wiring board having a circuit formed on the metal-clad laminate, a semiconductor package having a semiconductor element mounted on the printed wiring board, and a support for forming a coreless substrate and a support for forming a semiconductor redistribution layer, each containing the metal-clad laminate.

[0035] According to the method of the present invention, a metal-clad laminate having excellent thickness accuracy can be obtained without high filling of an inorganic filler, and thus a metal-clad laminate having good workability can be obtained. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 This is a conceptual diagram showing an example of an embodiment of the production method of the present invention.

[0037] Figure 2 This is a conceptual diagram showing an example of an embodiment of the production method of the present invention.

[0038] Figure 3 This is a conceptual diagram showing an example of a process for manufacturing a coreless substrate using the coreless substrate forming support body of the present invention.

[0039] Figure 4 This figure shows the results of measuring the surface roughness (Ra) of the surface of the laminated body before polishing used in Example 1 using a high-precision three-dimensional surface roughness measuring system (Wyko NT9100, manufactured by Veeco Instruments).

[0040] Figure 5This figure shows the results of measuring the surface roughness (Ra) of the surface of the cured product of the polished prepreg obtained in Example 1 using a high-precision three-dimensional surface roughness measuring system (Wyko NT9100, manufactured by Veeco Instruments).

[0041] Figure 6 This is a digital microscope image of the cross section of the copper-clad laminate A obtained in Example 1.

[0042] Figure 7 This is a conceptual diagram showing a state in which the thickness of the resin composition layer decreases at the end portion when a metal-clad laminate (pressed sheet) is produced by press molding. DETAILED DESCRIPTION

[0043] In the numerical range described in this specification, the upper limit or lower limit of its numerical range can be replaced with the value shown in the embodiment. In addition, about the lower limit and upper limit of numerical range, respectively can be arbitrarily combined with the lower limit or upper limit of other numerical ranges.

[0044] Furthermore, unless otherwise specified, each component and material listed in this specification may be used alone or in combination of two or more.

[0045] Arbitrary combinations of the matters described in this specification are also included in the present invention.

[0046] [Method for Manufacturing Metal-Clad Laminated Plate]

[0047] One aspect of the method for producing a metal-clad laminate of the present invention is a method for producing a metal-clad laminate, comprising:

[0048] (1) a step of polishing at least one surface of a cured product of a prepreg comprising a thermosetting resin composition and a base material [hereinafter sometimes referred to as step (1)];

[0049] (2-1) A step of laminating a metal foil on the surface polished in the above step (1) to form a metal-clad laminate [hereinafter sometimes referred to as step (2-1)].

[0050] Another aspect of the method for producing a metal-clad laminate of the present invention is a method for producing a metal-clad laminate, comprising:

[0051] (1) a step of polishing at least one surface of a cured product of a prepreg comprising a thermosetting resin composition and a base material;

[0052] (2-2) A step of forming a metal-clad laminate by laminating a metal foil and a thermosetting resin film, or laminating a thermosetting resin film with a metal foil on the surface polished in the above-mentioned step (1), so that the thermosetting resin film becomes the above-mentioned polished surface side [hereinafter sometimes referred to as step (2-2)].

[0053] Please refer to the following as needed Figure 1 or Figure 2 The above-mentioned step (1) will be described in detail.

[0054] <Process (1)>

[0055] Step (1) is a step of grinding at least one surface of a cured prepreg 1 comprising a thermosetting resin composition 6 and a substrate 7. In the present invention, the term "cured prepreg" refers to a cured prepreg in a C-stage state of the thermosetting resin composition contained in the prepreg, and excludes a cured prepreg in a B-stage state of the thermosetting resin composition. Furthermore, "at least one surface of the cured prepreg 1" refers to at least one of the two surfaces with the largest area in the cured prepreg 1, and excludes surfaces in the thickness direction (side surfaces). However, grinding of surfaces in the thickness direction (side surfaces) in addition to "at least one surface of the cured prepreg 1" is not excluded.

[0056] The cured product 1 of the prepreg used in step (1) can be obtained by etching away the metal foil of the metal-clad laminate whose surface has not been polished. In other words, the metal-clad laminate obtained by placing metal foil on one or both sides of one or more prepreg sheets and laminating them by press molding has insufficient thickness accuracy due to surface undulations. Therefore, by etching away the metal foil from the metal-clad laminate and performing step (1), the surface undulations are eliminated, thereby forming a metal-clad laminate with high thickness accuracy.

[0057] Here, the so-called surface undulation refers to undulations that are repeated at intervals greater than the surface roughness. In the present invention, the surface is observed using a high-precision 3D surface shape roughness measuring system under the conditions described in the examples. Figure 4As shown, if the surface roughness (arithmetic mean roughness: Ra) is 1.0 μm or less and exceeds 1.0 μm within a wide range (where the locations are arbitrary) of 95 μm on the X-axis and 95 μm on the Y-axis, the surface is considered to be highly undulating, and in this case, the thickness accuracy is reduced. The greater the surface roughness of the areas exceeding 1.0 μm (e.g., 1.5 μm or more, 2.0 μm or more), the greater the surface undulation. Because surface undulation is eliminated in the present invention, when surface roughness is observed using the high-precision 3D surface roughness measurement system, the surface roughness over the entire surface of the cured prepreg is 1.0 μm or less, preferably 0.9 μm or less, and more preferably 0.8 μm or less.

[0058] The method for etching away the metal foil of the metal-clad laminate where the surface of the internal solidified material has not been polished is not particularly limited, and conventional methods for etching away the metal foil of metal-clad laminates used in the manufacture of printed wiring boards can be employed. For example, the metal foil can be etched away using ferric chloride solution, ammonium persulfate, or the like.

[0059] It should be noted that as a metal-clad laminate whose surface as an internal cured product is not polished, a commercially available metal-clad laminate can be used, or it can be manufactured by a known method. As a manufacturing method, for example, a cured product can be used in which a metal foil is arranged on one or both sides of a material obtained by stacking one or more (for example, 2 to 20) prepregs containing a thermosetting resin composition and a substrate, and then laminated to form a laminate. The above-mentioned thermosetting resin composition and the above-mentioned substrate will be described later. There are no particular restrictions on the above-mentioned laminated molding conditions, and examples include: using a multi-stage press, a multi-stage vacuum press, continuous molding, an autoclave molding machine, etc., and the conditions of a temperature of 100 to 250°C, a pressure of 0.2 to 10 MPa, and a heating time of 0.1 to 5 hours.

[0060] Examples of the metal foil of the metal-clad laminate whose internal cured product surface is not polished include copper foil, nickel foil, and aluminum foil. Among these, copper foil is preferred. The thickness of the metal foil is not particularly limited, but is preferably 0.5 to 150 μm, more preferably 1 to 100 μm, further preferably 5 to 50 μm, particularly preferably 5 to 30 μm, and most preferably 7 to 18 μm.

[0061] The surface 2 to be ground can be at least one surface of the cured product, but from the perspective of fully eliminating surface undulations and increasing plate thickness accuracy, it is preferred to grind both surfaces of the cured product. Here, the so-called "at least one surface of the cured product" refers to at least one surface among the two surfaces with the largest area in the cured product, and does not include the surface (side surface) in the thickness direction. In addition, the so-called "both surfaces of the cured product" refers to the two surfaces with the largest area in the cured product, and does not include the surface (side surface) in the thickness direction. However, in addition to "both surfaces of the cured product", grinding of the surface (side surface) in the thickness direction is not excluded.

[0062] Note that, from the viewpoint of sufficiently eliminating surface undulations and improving plate thickness accuracy, it is preferable to polish the entire surface of the polishing object.

[0063] The dimensions of the cured prepreg 1 are not particularly limited. The dimensions of the press-formed metal-clad laminate (i.e., the so-called pressed sheet before being cut to specified dimensions) are preferably 200 mm to 1300 mm long and 200 mm to 1300 mm wide on the largest surface. Furthermore, the cured prepreg can be used even if, for example, at least a portion within a range of 70 mm from an end of the cured prepreg (or within a range of 50 mm from such an end) has a thickness that is thinner than the thickness of the central portion 3 of the cured prepreg. The term "within 70 mm from an end of the cured prepreg" refers to a range within 70 mm from any end of the cured prepreg, measured perpendicularly to the end, toward the interior of the cured prepreg.

[0064] The method for polishing the surface of the cured product is not particularly limited, but is preferably performed by a method selected from the group consisting of: (i) CMP (chemical mechanical polishing); (ii) mechanical polishing such as fly shearing, grinding, sandblasting, belt grinding, and frosted polishing; and (iii) chemical polishing using persulfate, hydrogen peroxide-sulfuric acid mixtures, inorganic acids, organic acids, and the like. Among these, polishing using CMP, fly shearing, and grinding is more preferred. One polishing method may be used alone, or two or more may be used in combination.

[0065] Polishing reduces the surface roughness of the polished cured product, resulting in a surface roughness (Ra) of preferably 1.0 μm or less, more preferably 0.9 μm or less, and even more preferably 0.8 μm or less. In the present invention, surface roughness (Ra) can be measured using a stylus profilometer (manufactured by Bruker Corporation, trade name "DektakXT").

[0066] The CMP method is mechanical polishing accompanied by chemical etching by an alkaline polishing solution. While there are no particular limitations on the CMP method, the use of the CMP method can be achieved. For example, the method described in "Ota Masaki, et al., 'Optical endpoint detection monitor for oxide film CMP' (Optical endpoint detection monitor for oxide film CMP)" (online), Ebara Times, No. 207 (April 2005), retrieved on June 12, 2005), can be used. <URL:https: / / www.ebara.co.jp / about / technologies / abstract / detail / _icsFiles / afieldfile / 2016 / 04 / 25 / 207_P25.pdf> " CMP device, etc. In addition, as the above-mentioned mechanical polishing, for example, flying shears are not particularly limited, and it is a method of performing physical grinding (polishing) using a grinding device using a diamond turning tool, such as an automatic surface planer (manufactured by DISCO Co., Ltd., trade name "DAS8930") or a grinder (manufactured by DISCO Co., Ltd., trade names "DFG8540" and "DFG8560") corresponding to 300 mm wafers.

[0067] Through this step (1), the surface undulations of the cured prepreg can be eliminated and the thickness accuracy can be improved. It can be said that the thickness of the cured prepreg is substantially uniform. Here, the term "substantially uniform" includes not only a state where the thickness is completely uniform, but also a state where the thickness is uniformed, although not completely, to the extent that the surface undulations fall within the above-mentioned range.

[0068] In addition, if Figure 1 and Figure 2 As shown, regarding the above-mentioned grinding, it is preferable to grind the entire surface until the thickness matches the thinnest part 5 in the cured prepreg. Here, the so-called "matching the thickness of the thinnest part 5 in the cured prepreg" means aligning the thickness of the entire prepreg to a degree that the thickness is roughly uniform. By grinding in this way, the thickness of the entire cured product is roughly uniform, so there is no need to discard the parts of the cured product that have become thinner. During grinding, there is no particular problem even if the base material in the prepreg is ground down to the ground, but it is also possible to adjust the grinding to a degree that the base material is not ground.

[0069] (Thermosetting resin composition)

[0070] As the thermosetting resin composition contained by the above-mentioned prepreg, as long as it contains thermosetting resin, there is no particular restriction. As thermosetting resin, for example, epoxy resin, phenolic resin, unsaturated imide resin, cyanate resin, isocyanate resin, benzoxazine resin, oxetane resin, unsaturated polyester resin, allyl resin, dicyclopentadiene resin, silicone resin, modified silicone resin, triazine resin, melamine resin, urea resin, furan resin etc. can be listed. In addition, there is no particular limitation on these, and known thermosetting resin can be used. These can be used alone or in combination with more than two kinds. Among these, epoxy resin, unsaturated imide resin, modified silicone resin are preferably used.

[0071] The epoxy resin is not particularly limited, and examples thereof include bisphenol-type epoxy resins such as bisphenol A epoxy resin, bisphenol F epoxy resin, and bisphenol S epoxy resin; alicyclic epoxy resins; aliphatic chain epoxy resins; phenol-formaldehyde epoxy resins such as phenol novolac epoxy resin, cresol novolac epoxy resin, bisphenol A novolac epoxy resin, and bisphenol F novolac epoxy resin; phenol aralkyl epoxy resins; stilbene epoxy resins; dicyclopentadiene epoxy resins; naphthalene-skeletal epoxy resins such as naphthol novolac epoxy resin and naphthol aralkyl epoxy resin; biphenyl epoxy resins; biphenyl aralkyl epoxy resins; xylylene epoxy resins; and dihydroanthracene epoxy resins. From these, either a naphthalene-skeletal epoxy resin or a naphthol aralkyl epoxy resin can be selected.

[0072] Examples of the unsaturated imide resin include maleimide resin, addition reaction products of a maleimide resin and a monoamine compound, and reaction products of a maleimide resin, a monoamine compound, and a diamine compound. The maleimide compound is not particularly limited, and examples thereof include bis(4-maleimidophenyl)methane, polyphenylmethanemaleimide, bis(4-maleimidophenyl)ether, 3,3′-dimethyl-5,5′-diethyl-4,4′-diphenylmethanebismaleimide, 4-methyl-1,3-phenylenebismaleimide, m-phenylenebismaleimide, bis(4-maleimidophenyl)sulfone, bis(4-maleimidophenyl)sulfide, bis(4-maleimidophenyl)ketone, 2,2-bis(4-(4-maleimidophenoxy)phenyl)propane, bis(4-(4-maleimidophenoxy)phenyl)sulfone, 4,4′-bis(3-maleimidophenoxy)biphenyl, and 1,6-bismaleimido-(2,2,4-trimethyl)hexane. From these, bis(4-maleimidophenyl)methane can be selected.

[0073] The monoamine compound is preferably a monoamine compound having an acidic substituent (e.g., a hydroxyl group, a carboxyl group, etc.), and specific examples thereof include o-aminophenol, m-aminophenol, p-aminophenol, o-aminobenzoic acid, m-aminobenzoic acid, p-aminobenzoic acid, o-aminobenzenesulfonic acid, m-aminobenzenesulfonic acid, p-aminobenzenesulfonic acid, 3,5-dihydroxyaniline, and 3,5-dicarboxyaniline.

[0074] The diamine compound is preferably a diamine compound having at least two benzene rings, more preferably a diamine compound having at least two benzene rings in a straight chain between two amino groups, and examples thereof include 4,4'-diaminodiphenylmethane, 4,4'-diamino-3,3'-dimethyl-diphenylmethane, 4,4'-diamino-3,3'-diethyl-diphenylmethane, 4,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl sulfone, 3,3'-diaminodiphenyl sulfone, and 4,4'-diaminodiphenyl ketone.

[0075] As the unsaturated imide resin, for example, the maleimide compounds described in JP-A-2018-165340 and the like can also be used.

[0076] The thermosetting resin composition preferably has the following configuration: in addition to the thermosetting resin, it may contain, as needed, at least one selected from a curing agent, a curing accelerator, an inorganic filler, an organic filler, a coupling agent, a leveling agent, an antioxidant, a flame retardant, a flame retardant aid, a thixotropy imparting agent, a tackifier, a thixotropy imparting agent, a flexible material, a surfactant, and a photopolymerization initiator. In particular, in the present invention, the inorganic filler can improve plate thickness accuracy without high filling, and thus the content of the inorganic filler can be, for example, set to 10 to 60% by volume, or 20 to 60% by volume, or 30 to 60% by volume. Within this numerical range, the upper limit can be further set to 57% by volume, or 55% by volume. However, in the case where the inorganic filler needs to be highly filled, the present invention does not necessarily deny that the content of the inorganic filler exceeds 60% by volume. For example, the upper limit of the numerical range of the above content can be set to 70% by volume, or 80% by volume.

[0077] Alternatively, a thermosetting resin composition may be used, for example, containing a modified silicone compound (modified silicone resin) as described in International Publication No. 2012 / 099133 and, if necessary, at least one selected from the group consisting of other thermosetting resins, a curing agent, a curing accelerator, an inorganic filler, a thermoplastic resin, an elastomer, an organic filler, a flame retardant, an ultraviolet absorber, an antioxidant, a photopolymerization initiator, a fluorescent brightener, and an adhesion enhancer.

[0078] The modified silicone compound is preferably a silicone compound modified with amino groups at both ends. Specifically, it is a silicone compound modified with amino groups at both ends obtained by reacting (A) a siloxane diamine represented by the following general formula (1), (B) a maleimide compound having at least two N-substituted maleimide groups in its molecular structure, and (C) an amine compound having an acidic substituent represented by the following general formula (2). Details are described in International Publication No. 2012 / 099133.

[0079] [Chemical Formula 1]

[0080]

[0081] [In formula (1), multiple R 1 Each independently represents an alkyl group, a phenyl group or a substituted phenyl group, and may be the same as or different from each other. 2 Each independently represents an alkyl group, a phenyl group or a substituted phenyl group, and may be the same as or different from each other, R 3 and R 4 Each independently represents an alkyl group, a phenyl group or a substituted phenyl group, and R 5 and R 6 Each independently represents a divalent organic group. n represents an integer of 2 to 50.]

[0082] [Chemical Formula 2]

[0083]

[0084] [In formula (2), R 7 When there are multiple groups, each independently represents a hydroxyl group, a carboxyl group or a sulfonic acid group, and R 8 When there are multiple ""s, each independently represents a hydrogen atom, an aliphatic hydrocarbon group having 1 to 5 carbon atoms, or a halogen atom. x is an integer of 1 to 5, y is an integer of 0 to 4, and x + y = 5.

[0085] (Base material)

[0086] As the base material contained in the above-mentioned prepreg, a sheet-shaped reinforcing base material is used, and a well-known base material used for laminated plates for various electrical insulating materials can be used. Examples of the material of the base material include: natural fibers such as paper and cotton linter; inorganic fibers such as glass fiber and asbestos; organic fibers such as aromatic polyamide, polyimide, polyvinyl alcohol, polyester, tetrafluoroethylene, and acrylonitrile-based fibers; and mixtures thereof. Among these, glass fiber is preferred from the perspective of flame retardancy. Examples of the glass fiber base material include: woven fabrics using E-glass, C-glass, D-glass, S-glass, etc., or glass woven fabrics obtained by bonding short fibers with an organic adhesive; base materials obtained by mixing glass fibers and cellulose fibers, etc. More preferred is glass woven fabric using E-glass.

[0087] These substrates may be in the form of, for example, woven fabric, non-woven fabric, coarse sand, chopped strand mat, or surface mat. It should be noted that the material and shape are selected according to the intended use and performance of the molded article, and one type may be used alone, or two or more types of materials and shapes may be combined as needed.

[0088] The thickness of the substrate can be, for example, 0.01 to 0.5 mm. From the perspectives of formability and high-density wiring, it is preferably 0.015 to 0.2 mm, and more preferably 0.02 to 0.15 mm. These substrates are preferably those surface-treated with a silane coupling agent or the like, or those subjected to mechanical fiber-opening treatment, from the perspectives of heat resistance, moisture resistance, and processability.

[0089] (Prepreg)

[0090] By impregnating the above-mentioned thermosetting resin composition into the above-mentioned substrate and then performing a heat treatment, a prepreg after the thermosetting resin composition is B-staged can be obtained. With regard to the prepreg, from the viewpoint of the handleability and viscosity of the prepreg, it is preferably provided with a cooling process for cooling it. The cooling of the prepreg can be carried out by natural cooling, or by using a cooling device such as an air supply device or a cooling roller. The temperature of the cooled prepreg is usually 5 to 80°C, preferably 8 to 50°C, more preferably 10 to 30°C, and further preferably room temperature. In addition, the content of the thermosetting resin composition in the prepreg in terms of solid content is not particularly limited, but is preferably 20 to 90% by mass, more preferably 30 to 85% by mass, and further preferably 50 to 80% by mass. The thickness of the prepreg is not particularly limited, but is, for example, preferably 20 to 150 μm, and more preferably 60 to 120 μm.

[0091] <Process (2-1) and Process (2-2)>

[0092] Step (2-1) is a step of laminating metal foil 9 on the surface polished in step (1) to form a metal-clad laminate. On the other hand, step (2-2) is a step of laminating metal foil 9 and thermosetting resin film 10, or laminating thermosetting resin film 11 with metal foil, on surface 8 polished in step (1) to form metal-clad laminate 12, so that thermosetting resin film 10 faces the polished surface 8. It should be noted that the thermosetting resin film 11 with metal foil is formed by arranging thermosetting resin film 10 on metal foil 9.

[0093] After step (1), either step (2-1) or step (2-2) can be selected, but step (2-2) is preferably selected, in which a thermosetting resin layer is formed to the depth obtained by grinding the cured prepreg. By selecting step (2-2), the thickness of the prepreg can be restored to the thickness before grinding, regardless of the amount of grinding in step (1), and can also be adjusted to any desired thickness.

[0094] The metal of the metal foil 9 (including the metal foil with the thermosetting resin film 11 attached thereto) is not particularly limited as long as it is a metal used for electrical insulating material applications. From the viewpoint of conductivity, copper, gold, silver, nickel, platinum, molybdenum, ruthenium, aluminum, tungsten, iron, titanium, chromium, or an alloy containing at least one of these metal elements is preferred, copper and aluminum are more preferred, and copper is even more preferred.

[0095] The raw material of the thermosetting resin film used in the step (2-2) is preferably the same as the thermosetting resin composition contained in the prepreg used in the step (1).

[0096] [Metal-clad laminate]

[0097] The present invention also provides a metal-clad laminate obtained by the above-mentioned production method.

[0098] Because the thickness of the internal cured product is substantially uniform, the thickness of the metal-clad laminate of the present invention is also substantially uniform. Specifically, the difference between the maximum and minimum thickness values can be 20 μm or less, resulting in excellent thickness accuracy. The difference between the maximum and minimum thickness values is more preferably 10 μm or less, and even more preferably 5 μm or less.

[0099] Here, the difference between the maximum value and the minimum value of the thickness and the difference between them are values measured according to the following method, more specifically, values measured according to the method described in Examples.

[0100] <Difference between Maximum and Minimum Thickness Values and Calculation Method of the Difference>

[0101] A 550 mm square metal-clad laminate was cut into 50 mm square pieces, resulting in a total of 81 pieces. Samples were selected at 17 locations, including the ends and the center, and the thickness was measured at four random points using a micrometer. The maximum and minimum plate thicknesses, as well as their difference, were calculated from the data at the 68 total points.

[0102] Furthermore, the metal-clad laminate obtained by the manufacturing method of the present invention can have a thickness standard deviation (σ) of 10 μm or less, and thus has excellent thickness accuracy. This standard deviation (σ) is more preferably 5 μm or less, and even more preferably 3 μm or less. It should be noted that the thickness standard deviation (σ) can be obtained by, for example, measuring the thickness of n arbitrary locations of the metal-clad laminate and denoting their thicknesses as T1, T2, ..., T n When the average thickness of the metal-clad laminate is defined as T, the standard deviation at n locations can be calculated using the following formula.

[0103] [Mathematical formula 1]

[0104]

[0105] One embodiment of a metal-clad laminate obtained by the production method of the present invention includes a metal-clad laminate comprising: (a) a cured product of a prepreg comprising a thermosetting resin composition and a substrate, wherein at least one surface of the cured product is polished; (b) a thermosetting resin composition layer not comprising a substrate; and (c) a metal foil. In particular, the metal-clad laminate can be produced by performing steps (1) and (2-2) of the above-described production method.

[0106] The above-mentioned (a) is not particularly limited, but is preferably a state where both surfaces of the cured product are polished. Preferred forms of the polishing method are as described above.

[0107] [Printed wiring board]

[0108] The present invention also provides a printed wiring board comprising the metal-clad laminate.

[0109] More specifically, the printed wiring board of the present invention can be manufactured by performing circuit processing on the metal foil of the metal-clad laminate. Circuit processing can be performed, for example, by forming a resist pattern on the surface of the metal foil, removing unnecessary portions of the metal foil by etching, peeling off the resist pattern, forming the necessary through-holes with a drill, forming the resist pattern again, plating to connect the through-holes, and finally peeling off the resist pattern. On the surface of the printed wiring board thus obtained, the above-mentioned metal-clad laminate can be further laminated under the same conditions as above, and further circuit processing can be performed in the same manner as above to produce a multilayer printed wiring board. In this case, it is not necessary to form through-holes; vias (Japanese: ビアホール) can also be formed, or both can be formed. Such multilayering is performed to the desired number of sheets.

[0110] The printed wiring board of the present invention obtained in this manner is also excellent in board thickness accuracy.

[0111] [Semiconductor Package]

[0112] The semiconductor package of the present invention is formed by mounting a semiconductor on the printed wiring board of the present invention. The semiconductor package of the present invention can be manufactured by mounting a semiconductor chip, a memory, etc. at a predetermined position on the printed wiring board of the present invention. Since the printed wiring board of the present invention has excellent thickness accuracy, the semiconductor package of the present invention has the following tendencies: (1) the yield rate during actual mounting of the semiconductor chip is improved; (2) the formability of fine wiring with L / S = 2μm / 2μm or less on the build-up film or the redistribution layer is improved; (3) the warping amount is reduced, and deviations in the warping amount are less likely to occur.

[0113] [Coreless substrate forming support body]

[0114] The present invention also provides a support for forming a coreless substrate, comprising the metal-clad laminate of the present invention. A coreless substrate can be produced by sequentially laminating layers of an insulating resin composition having a circuit pattern on the support (core substrate) for forming a coreless substrate to form a build-up layer, and then separating the support. The support for forming a coreless substrate of the present invention has excellent thickness accuracy, thereby reducing warping and surface undulations in the resulting coreless substrate, making it suitable for improving the thickness accuracy of the coreless substrate.

[0115] It should be noted that there is no particular limitation on the method for forming the above-mentioned laminated layer, and a known method can be used. Figure 3 To explain, for example, the build-up layer can be formed by the following method.

[0116] First, a prepreg 14 is placed on the coreless substrate forming support (core substrate) 13 of the present invention. It should be noted that, in addition to placing an adhesive layer on the coreless substrate forming support (core substrate) 13, the prepreg 14 can also be placed. The prepreg 14 is then heated and cured to form an insulating layer. Next, vias 15 are formed by drilling or laser processing using a YAG laser, CO2 laser, or the like, and then surface roughening and surface decontamination are performed as needed. Next, a circuit pattern 16 is formed by a subtractive process, a fully additive process, a semi-additive process (SAP), a modified semi-additive process (m-SAP), or the like. By repeating the above process, a build-up layer 17 is formed. By separating the formed build-up layer 17 from the coreless substrate forming support (core substrate) 13, a coreless substrate 18 is obtained. It should be noted that build-up layer 17 may be formed on one surface or both surfaces of support body (core substrate) 13 .

[0117] [Support for Forming Semiconductor Redistribution Layer]

[0118] The present invention also provides a support for forming a semiconductor redistribution layer, which contains the metal-clad laminate of the present invention. The so-called semiconductor redistribution layer refers to an insulating layer provided with copper wirings connected to solder balls, and is usually an insulating layer provided between a semiconductor chip and solder balls. In order to form this semiconductor redistribution layer, it is preferable to use a resin film for forming a semiconductor redistribution layer. The support for forming a semiconductor redistribution layer of the present invention effectively functions as a support for the resin film for forming a semiconductor redistribution layer because of its good plate thickness accuracy.

[0119] Examples

[0120] Next, the present invention will be described in more detail by the following examples, but these examples do not limit the present invention in any sense.

[0121] [Example 1]

[0122] First, a prepreg was produced according to the following steps.

[0123] 100 parts by mass of a bis-terminal amino-modified silicone compound, 222 parts by mass of bis(4-maleimidophenyl)methane, and 8.5 parts by mass of p-aminophenol were reacted to obtain a solution containing a modified silicone compound. Then, 16 parts by mass of this solution containing a modified silicone compound, 16 parts by mass of a naphthol aralkyl type epoxy resin, 69 parts by mass of fused silica (average particle size: 0.5 μm), and 0.15 parts by mass of an isocyanate-capped imidazole (Japanese: イソシアネートマスクイミダゾール) were mixed to obtain a varnish with a resin content of 65% by mass. The obtained varnish was impregnated and coated on an E-glass cloth with a thickness of 0.1 mm and heated and dried to obtain a prepreg (the filling rate of fused silica: 50% by volume).

[0124] Eight pieces of the thus obtained prepregs were laminated, and low-smoothness type copper foils (Japanese: ロープロタイプ銅箔) (thickness 12 μm, maximum height roughness (Rz) of about 4.0 μm, manufactured by Mitsui Mining & Smelting Co., Ltd.) were overlapped on both sides thereof, and heat press molding was performed at a pressure of 0.5 MPa and a temperature of 200 to 230 °C for about 2 hours to obtain a laminate having copper foils on both sides (hereinafter, referred to as copper-clad laminate a).

[0125] Next, using the obtained copper-clad laminate a, the copper foil was removed by etching to obtain a laminate. For the surface of this laminate, the surface roughness (Ra) was measured under the following measurement conditions using a high-precision 3D surface shape roughness measurement system (manufactured by Veeco Instruments Inc., Wyko NT9100). The results are shown in Figure 4 .

[0126] Next, both the front and back surfaces (i.e., the two surfaces with the largest areas) of the laminate were polished and flattened using a grinding machine (automatic planer compatible with 300 mm wafers, manufactured by DISCO Co., Ltd., trade name "DAS8930") using a diamond drill. The surface roughness (Ra) of the polished surface was measured using a high-precision 3D surface roughness measurement system (Wyko NT9100, manufactured by Veeco Instruments) under the following measurement conditions. The results are shown in Figure 5 . It can be confirmed that Figure 4 compared to, Figure 5 The surface has small undulations.

[0127] Furthermore, a thermosetting resin film (10 μm thick) with the same composition as the prepreg "GEA-705G" was placed on both sides of the flattened laminate, and copper foil (12 μm thick) was further placed on the outer surface. Heat and pressure were applied by hot pressing to obtain a 550 mm square copper-clad laminate A capable of forming a circuit on the outermost layer. A cross-section of the copper-clad laminate A thus obtained was observed using a digital microscope (manufactured by KEYENCE, trade name "VHX-5000"). The image is shown in FIG. Figure 6 .

[0128] <Measurement conditions for high-precision 3D surface roughness measurement system>

[0129] Internal lens: 1x

[0130] External lens: 50 times

[0131] Measuring range: Any position within the range of 95μm (Y axis) x 95μm (X axis)

[0132] Measurement depth: 10 μm

[0133] Measurement method: Vertical scanning interferometry (VSI)

[0134] The copper-clad laminate obtained by the above method was evaluated according to the following evaluation methods. The results are shown in Table 1.

[0135] Evaluation Method

[0136] (1. Maximum and minimum thicknesses of copper-clad laminates and their difference)

[0137] The copper-clad laminate obtained in each example was cut into 50 mm square pieces using a wet diamond saw, resulting in a total of 81 pieces. Samples were selected at 17 locations, including the ends and the center, and the thickness was measured at four random points using a micrometer. The maximum and minimum thickness values, as well as their difference, were calculated from the data at the 68 total points.

[0138] (2. Drill bit machinability-decrease life)

[0139] A ULF Coated drill, the "MCW Z699MWU" (φ0.15 mm (small diameter) x φ3.5 mm (large diameter), manufactured by Union Tool Co., Ltd.), was used for drilling at a rotational speed of 200,000 rpm, a feed rate of 2.0 m / min, and a tool feed rate of 10.0 μm / rev. Evaluation was performed after 10,000 hits. The number of hits until breakage (breakage life) was calculated and used as an indicator of drill performance.

[0140] [Comparative Example 1]

[0141] In Example 1, the surface of the laminate in the copper-clad laminate a was not polished, but the copper-clad laminate a was used as it was, and each evaluation was performed according to the above-mentioned method.

[0142] [Reference Example 1]

[0143] In the production of copper-clad laminate a of Example 1, copper-clad laminate b was produced in the same manner, except that the filling rate of the inorganic filler in the prepreg was increased to 58% by volume. To confirm the drillability when the filling rate of the inorganic filler was increased, the drillability of copper-clad laminate b was evaluated according to the above method. The results are shown in Table 1.

[0144] [Table 1]

[0145]

[0146] Table 1 shows that the copper-clad laminate A obtained in Example 1 had extremely high thickness accuracy and good workability (drill workability). On the other hand, the copper-clad laminate a of the comparative example had inferior thickness accuracy compared to the copper-clad laminate A obtained in Example 1.

[0147] In addition, the copper-clad laminate b of Reference Example 1 in which the filling rate of the inorganic filler in the thermosetting resin composition was increased had a decreased workability (drill workability).

[0148] Industrial applicability

[0149] The metal-clad laminate obtained by the production method of the present invention is excellent in thickness accuracy and is therefore useful for printed wiring boards and semiconductor packages for electronic devices.

[0150] Description of Reference Signs

[0151] 1. Cured prepreg

[0152] 2 Surface to be ground

[0153] 3 Central part of the solidified material

[0154] 4 Parts that are thinner than the center of the cured product

[0155] 5 The thinnest part of the cured product

[0156] 6 Thermosetting resin composition

[0157] 7. Substrate

[0158] 8 Surface polished in step (1)

[0159] 9 metal foil

[0160] 10 Thermosetting resin film

[0161] 11 Thermosetting resin film with metal foil

[0162] 12 Metal-clad laminates

[0163] 13 Coreless substrate forming support (core substrate)

[0164] 14 Prepreg

[0165] 15 vias

[0166] 16 circuit patterns

[0167] 17 Layers

[0168] 18 coreless substrate

Claims

1. A method for manufacturing a metal-clad laminate, comprising: A step of sandwiching a prepreg comprising a thermosetting resin composition and a base material between metal foils and laminating the laminate by press molding, and etching away the metal foil of the resulting metal-clad laminate to obtain a cured product of the prepreg whose surface is not polished; (1) grinding at least one surface of the cured prepreg to eliminate surface undulations caused by press molding; (2-1) A step of laminating a metal foil on the surface polished in the step (1) to form a metal-clad laminate.

2. A method for manufacturing a metal-clad laminate, comprising: A step of sandwiching a prepreg comprising a thermosetting resin composition and a base material between metal foils and laminating the laminate by press molding, and etching away the metal foil of the resulting metal-clad laminate to obtain a cured product of the prepreg whose surface is not polished; (1) grinding at least one surface of the cured prepreg to eliminate surface undulations caused by press molding; (2-2) A step of forming a metal-clad laminate by laminating a metal foil and a thermosetting resin film, or laminating a thermosetting resin film with a metal foil, on the surface polished in the step (1) so that the thermosetting resin film faces the polished surface.

3. The method for producing a metal-clad laminate according to claim 1 or 2, wherein: In the step (1), both surfaces of the cured prepreg are polished.

4. The method for producing a metal-clad laminate according to claim 1 or 2, wherein: The grinding in the step (1) makes the thickness of the cured product of the prepreg substantially uniform.

5. The method for producing a metal-clad laminate according to claim 1 or 2, wherein: The cured prepreg has a largest surface area of 200 to 1300 mm in length and 200 to 1300 mm in width, and at least a portion within 70 mm from an end of the cured prepreg is thinner than a central portion of the cured prepreg.

6. The method for producing a metal-clad laminate according to claim 1 or 2, wherein: In the step (1), the entire surface is polished until the thickness matches the thinnest portion of the cured prepreg.

7. The method for producing a metal-clad laminate according to claim 1 or 2, wherein: In the step (1), polishing is performed by a method selected from the group consisting of: (i) chemical mechanical polishing (CMP); (ii) mechanical polishing such as flying shearing, grinding, sandblasting, belt grinding, and abrasive grinding; and (iii) chemical polishing using persulfate, a hydrogen peroxide-sulfuric acid mixture, an inorganic acid, or an organic acid.

8. The method for producing a metal-clad laminate according to claim 1 or 2, wherein: The difference between the maximum and minimum thicknesses of the obtained metal-clad laminate was 20 μm or less. 9 . A metal-clad laminate obtained by the production method according to claim 1 .

10. A metal-clad laminate comprising: (a) a cured product which is a cured product of a prepreg comprising a thermosetting resin composition and a substrate, wherein at least one surface of the cured product has been polished to eliminate surface roughness; (b) a thermosetting resin composition layer which does not include a substrate; and (c) a metal foil. The cured prepreg is obtained by sandwiching the prepreg between metal foils and laminating them by press molding, wherein the metal foil of the metal-clad laminate whose surface is not polished is removed by etching.

11. A printed wiring board comprising the metal-clad laminate according to claim 9 or 10. 12 . A semiconductor package comprising a semiconductor element mounted on the printed wiring board according to claim 11 . 13 . A support for forming a coreless substrate, comprising the metal-clad laminate according to claim 9 . 14 . A semiconductor redistribution layer forming support comprising the metal-clad laminate according to claim 9 .

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