Metal-clad laminate

Abstract

To provide a metal-clad laminate that has both a low coefficient of thermal expansion and a good adhesion property between an insulating layer and a metal layer.SOLUTION: There is provided a metal-clad laminate, comprising: an insulating layer containing a plurality of glass cloths and a resin composition; and a metal layer provided on both sides of the insulating layer, wherein in a cross section in a thickness direction of the insulating layer, when the thickness direction of the glass cloth is defined as a y direction and a direction perpendicular to the y direction is defined as an x direction, and in a first glass cloth having a maximum value of a y coordinate difference between a top and bottom at a predetermined x position among the plurality of glass cloths, when the y coordinate difference is defined as a [μm], and when a center-to-center distance in the y direction between the first glass cloth and a second glass cloth adjacent to the first glass cloth at the x position is defined as b [μm], and when the number of laminated glass cloths is defined as c [sheets] and a thickness of the insulating layer is defined as d [μm], a relationship between b / a<1 and a×c>d is satisfied.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a metal-clad laminate. [Background technology]

[0002] In recent years, with the demand for higher performance electronic devices, the integration and mounting of electronic components has become increasingly dense, and the printed wiring boards and other components used in these devices are becoming increasingly smaller and denser than ever before.

[0003] A known example of a printed wiring board is a metal-clad laminate having a metal layer provided on at least one surface of an insulating layer formed using a prepreg, and the metal layer is patterned.

[0004] Prepregs are produced, for example, by incorporating a resin composition, the main components of which are a thermosetting resin such as an epoxy resin and an inorganic filler, into a solvent to form a varnish, which is then impregnated into a substrate such as glass cloth and dried by heating (see, for example, Patent Document 1).

[0005] When the amount of resin composition in the prepreg is large, the effect of the thermal expansion coefficient of the resin component becomes large, resulting in a large thermal expansion coefficient for the prepreg (insulating layer) and, ultimately, the metal-clad laminate.On the other hand, electronic components mounted on printed wiring boards generally have a small thermal expansion coefficient.

[0006] In printed wiring boards using metal-clad laminates, if there is a large difference in the thermal expansion coefficient between them and the electronic components mounted on them, the printed wiring board may warp, so it is necessary to keep the thermal expansion coefficient of the metal-clad laminate low.

[0007] Therefore, conventionally, the increase in the thermal expansion coefficient of metal-clad laminates has been suppressed by increasing the content of inorganic filler in the resin composition (see, for example, Patent Document 2).

[0008] However, increasing the content of inorganic filler in the resin composition reduces the adhesion between the insulating layer and the metal layer. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-116941 [Patent Document 2] Patent No. 6969843 Summary of the Invention [Problem to be solved by the invention]

[0010] An object of the present invention is to provide a metal-clad laminate that has both a low coefficient of thermal expansion and good adhesion between the insulating layer and the metal layer. [Means for solving the problem]

[0011] These objects can be achieved by the present invention as set forth in (1) to (5) below. (1) A metal-clad laminate having an insulating layer containing a plurality of glass cloths and a resin composition, and metal layers provided on both sides of the insulating layer, In a cross section in the thickness direction of the insulating layer, when the thickness direction of the glass cloth is defined as the y direction and the direction perpendicular to the y direction is defined as the x direction, Among the plurality of glass cloths, a first glass cloth has the maximum value of the y coordinate difference between the top and bottom at a predetermined x position, and the y coordinate difference is a [μm]. At the x position, the center-to-center distance in the y direction between the first glass cloth and the second glass cloth adjacent to the first glass cloth is b [μm], The number of laminated glass cloths is c [sheets], When the thickness of the insulating layer is d [μm], A metal-clad laminate characterized by satisfying the relationships b / a<1 and a×c>d.

[0012] (2) The metal-clad laminate according to (1), wherein the resin composition contains a thermosetting resin and an inorganic filler.

[0013] (3) The metal-clad laminate according to (2) above, wherein the content of the inorganic filler in the resin composition is 5% by mass or more and 40% by mass or less.

[0014] (4) The metal-clad laminate according to any one of (1) to (3) above, wherein the ratio of the glass cloth in the insulating layer is 55% by mass or more and 80% by mass or less.

[0015] (5) The metal-clad laminate according to any one of (1) to (4) above, wherein the ash content of the insulating layer is 65% or more and 87% or less. [Effects of the Invention]

[0016] According to the present invention, it is possible to provide a metal-clad laminate that has both a low coefficient of thermal expansion and good adhesion between the insulating layer and the metal layer. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a cross-sectional view schematically showing one configuration example of a metal-clad laminate of the present invention. [Figure 2] 2 is an enlarged cross-sectional view showing a part of an insulating layer in the metal-clad laminate shown in FIG. 1. FIG. [Figure 3] 1A to 1C are diagrams illustrating an example of a method for producing a prepreg. [Figure 4] 1 is a cross-sectional SEM photograph of the metal-clad laminate of Example 1. [Figure 5] 1 is a cross-sectional SEM photograph of the metal-clad laminate of Comparative Example 1. [Figure 6] 1 is a graph showing dimensional changes with temperature for the metal-clad laminates of Example 1 and Comparative Example 1. DETAILED DESCRIPTION OF THE INVENTION

[0018] Preferred embodiments of the present invention will be described in detail below. [1] Metal-clad laminate First, the metal-clad laminate of the present invention will be described.

[0019] Fig. 1 is a cross-sectional view schematically showing one example of the configuration of a metal-clad laminate of the present invention, Fig. 2 is an enlarged cross-sectional view showing a part of an insulating layer in the metal-clad laminate shown in Fig. 1.

[0020] The metal-clad laminate 1 has an insulating layer 10 that is configured to include a plurality of glass cloths 11 and a resin composition 12 , and metal layers 2 that are provided on both sides of the insulating layer 10 . In the cross section of the metal-clad laminate 1 in the thickness direction of the insulating layer 10, when the thickness direction of the glass cloth 11 is the y direction and the direction perpendicular to the y direction is the x direction, the y coordinate difference between the top and bottom of the first glass cloth 11a among the multiple glass cloths 11 at a predetermined x position is a [μm], the center-to-center distance in the y direction between the first glass cloth 11a and the second glass cloth 11b adjacent to the first glass cloth 11a at the x position is b [μm], the number of laminated glass cloths 11 is c [sheets], and the thickness of the insulating layer 10 is d [μm], the relationships b / a<1 and a×c>d are satisfied.

[0021] By satisfying these conditions, it is possible to provide a metal-clad laminate 1 that has both a low coefficient of thermal expansion and good adhesion between the insulating layer 10 and the metal layer 2.

[0022] More specifically, adjacent first glass cloth 11a and second glass cloth 11b fit into the gaps between the uneven surfaces of the first and second glass cloths 11a, so that the y-coordinate difference a for the first glass cloth 11a, in other words, the thickness of the first glass cloth 11a, is smaller than the center-to-center distance b between the adjacent first and second glass cloths 11a, 11b.

[0023] This allows the number of laminated glass cloths 11 to be increased while suppressing an increase in the overall thickness of the insulating layer 10.

[0024] In addition, since the multiple glass cloths 11 penetrate into the gaps between the uneven surfaces of adjacent glass cloths 11, the product a×c of the thickness a of the first glass cloth 11a and the number c of laminated glass cloths 11 is smaller than the thickness d of the insulating layer 10.

[0025] This allows the number of laminated glass cloths 11 to be increased while suppressing an increase in the overall thickness of the insulating layer 10.

[0026] Furthermore, by increasing the number of glass cloths 11 in the insulating layer 10 without increasing the thickness, in other words, by increasing the proportion of glass cloths 11 in the entire insulating layer 10, the proportion of resin composition 12 in the entire insulating layer 10 can be relatively reduced.

[0027] Furthermore, by reducing the proportion of resin composition 12 in insulating layer 10, the effect of the thermal expansion coefficient of the resin component can be reduced, and the thermal expansion coefficient of insulating layer 10 as a whole and the thermal expansion coefficient of metal-clad laminate 1 as a whole can be made sufficiently small.

[0028] Specifically, even if the resin composition 12 does not contain a high content of inorganic filler, the thermal expansion coefficient of the insulating layer 10 as a whole and the thermal expansion coefficient of the metal-clad laminate 1 as a whole can be made sufficiently small.

[0029] By keeping the content of inorganic filler in resin composition 12 low, adhesion between insulating layer 10 and metal layer 2 can be ensured.

[0030] This allows the metal-clad laminate 1 to have both a low coefficient of thermal expansion and good adhesion between the insulating layer 10 and the metal layer 2.

[0031] Furthermore, by satisfying the above conditions, even if the proportion of resin in insulating layer 10 is small, the occurrence of voids is effectively suppressed.

[0032] On the other hand, if the above conditions are not met, the above excellent effects cannot be obtained.

[0033] For example, if the adjacent first glass cloth 11a and second glass cloth 11b do not fit into the gaps between the surface irregularities, b / a≧1, and it is not possible to sufficiently increase the number of laminated glass cloths 11 while suppressing an increase in thickness.

[0034] As a result, the proportion of the resin composition 12 in the insulating layer 10 cannot be reduced sufficiently, and it is not possible to achieve both a low coefficient of thermal expansion and good adhesion between the insulating layer 10 and the metal layer 2.

[0035] Furthermore, for example, if adjacent glass cloths 11 do not fit into the gaps between the uneven surfaces, a×c≦d will be satisfied, and it will be impossible to sufficiently increase the number of laminated glass cloths 11 while suppressing an increase in thickness.

[0036] As a result, the proportion of the resin composition 12 in the insulating layer 10 cannot be reduced sufficiently, and it is not possible to achieve both a low coefficient of thermal expansion and good adhesion between the insulating layer 10 and the metal layer 2.

[0037] The excellent effects of the present invention can be obtained by satisfying both the relationships b / a<1 and a×c>d, and if either one of them is not satisfied, the excellent effects described above cannot be obtained.

[0038] As shown in FIG. 2, in this specification, when the y coordinate of the top of the glass cloth 11 is y1 and the y coordinate of the bottom of the glass cloth 11 is y2 at a predetermined x position (x1) in the cross section of the insulating layer 10 in the thickness direction, the glass cloth 11 having the largest y coordinate difference (y1-y2) among the multiple glass cloths 11 is defined as the first glass cloth 11a, and the y coordinate difference (y1-y2) for the first glass cloth 11a is defined as a [μm].

[0039] At the x1 position, the center-to-center distance in the y direction between the first glass cloth 11a and the second glass cloth 11b adjacent to the first glass cloth 11a is defined as b [μm]. The centers in the y direction of the first glass cloth 11a and the second glass cloth 11b are defined as the midpoint between the top y1 and the bottom y2 at the x1 position.

[0040] As described above, in the present invention, it is sufficient that a and b satisfy the relationship b / a<1, but it is preferable that they satisfy the relationship b / a<0.9, and it is more preferable that they satisfy the relationship b / a<0.85. This makes it possible to make the above-mentioned effects of the present invention more pronounced.

[0041] Furthermore, as described above, in the present invention, it is sufficient that the relationship between a, c, and d satisfies a×c>d, but it is preferable that the relationship between a×c>1.10d is satisfied, and it is more preferable that the relationship between a×c>1.15d is satisfied. This makes it possible to make the above-mentioned effects of the present invention more pronounced.

[0042] [1-1] Insulating layer The insulating layer 10 is configured to include a plurality of glass cloths 11 and a resin composition 12 . In the following description, the glass cloth 11 impregnated with the resin composition 12 may be referred to as a "prepreg."

[0043] [1-1-1] Glass cloth The glass cloth 11 is a fiber base material made of glass fibers.

[0044] The glass constituting the glass cloth 11 may include at least one glass selected from the group consisting of T glass, S glass, E glass, NE glass, and quartz glass, and among these, it is preferable to include S glass or T glass.

[0045] This allows the thermal expansion coefficient of the glass cloth 11 to be further reduced, and the thermal expansion coefficient of the prepreg to be further reduced.

[0046] The glass cloth 11 is a woven fabric, a nonwoven fabric, or the like. When the glass cloth 11 is a woven fabric, the weaving method (weave) is not particularly limited, but examples include plain weave, twill weave, satin weave, leno weave, and twill weave, and among these, plain weave is preferred.

[0047] This allows the adjacent glass cloths 11 to easily enter into the gaps between the unevenness of the surface, making it easier to realize the above-described configuration of the present invention.

[0048] The glass cloth 11 is preferably constructed by weaving warp bundles each consisting of a plurality of warp threads and weft bundles each consisting of a plurality of weft threads so that they intersect with each other. Such glass cloth 11 is considered to be easily impregnated with the resin composition 12 uniformly. This allows the production of a prepreg with minimal unevenness in mechanical strength.

[0049] When the glass cloth 11 is constructed by weaving warp bundles each consisting of a plurality of warp threads and weft bundles each consisting of a plurality of weft threads so that they cross each other, the density of the warp bundles is preferably 30 threads / 25 mm or more and 90 threads / 25 mm or less, and more preferably 35 threads / 25 mm or more and 80 threads / 25 mm or less.

[0050] This makes it possible to suppress an increase in cost and obtain a higher strength even when the glass cloth 11 is thin.

[0051] The density of the weft bundle is preferably 30 threads / 25 mm or more and 90 threads / 25 mm or less, and more preferably 35 threads / 25 mm or more and 80 threads / 25 mm or less.

[0052] This makes it possible to suppress an increase in cost and obtain a higher strength even when the glass cloth 11 is thin.

[0053] Furthermore, by satisfying the above conditions, it is possible to ensure higher strength while having a suitable degree of unevenness, which allows adjacent glass cloths 11 to easily fit into the gaps between the uneven surfaces, making it easier to achieve the above-described configuration of the present invention.

[0054] The thickness of the glass cloth 11 is preferably 5 μm or more and 150 μm or less, more preferably 10 μm or more and 130 μm or less, and even more preferably 20 μm or more and 100 μm or less.

[0055] This allows the cost, availability, strength, etc. of the glass cloth 11 to be favorable.

[0056] The basis weight of the glass cloth 11 is not particularly limited, but is preferably 20 g / m 2 More than 180g / m 2 Preferably less than 30 g / m 2 More than 170g / m 2 More preferably, it is 40 g / m or less. 2 More than 160g / m 2 More preferably, it is:

[0057] This allows the resin composition 12 to be easily impregnated into the glass cloth 11. This makes it possible to suppress the generation of voids and improve the homogeneity of the prepreg. Furthermore, the cost, availability, strength, etc. of the glass cloth 11 can be made favorable.

[0058] The insulating layer 10 includes a plurality of glass cloths 11 . In this case, it is preferable that the plurality of glass cloths 11 have substantially the same conditions. This makes it easier to realize the above-described configuration of the present invention.

[0059] The conditions of the glass cloth 11 include, for example, thickness, thickness of glass fibers, density of warp and weft bundles, weaving method, and the like.

[0060] Specifically, for example, it is preferable to use a plurality of glass cloths 11 made of the same product.

[0061] This allows the conditions of the plurality of glass cloths 11 to be substantially the same, making it easier to achieve the above-described configuration of the present invention more suitably.

[0062] The proportion of the glass cloth 11 in the insulating layer 10 is preferably 55% by mass or more and 80% by mass or less, more preferably 57.5% by mass or more and 77.5% by mass or less, and even more preferably 60% by mass or more and 75% by mass or less.

[0063] This allows the metal-clad laminate 1 to have a low thermal expansion coefficient and a higher level of adhesion between the insulating layer 10 and the metal layer 2, and also improves the formability when manufacturing the metal-clad laminate 1 by hot press molding.

[0064] [1-1-2] Resin composition The resin composition 12 contains at least a resin material, and preferably contains a thermosetting resin and an inorganic filler.

[0065] This allows the resin composition to have better mechanical strength, chemical resistance, and electrical insulation properties.

[0066] [1-1-2-1]Thermosetting resin Examples of thermosetting resins include phenolic resins, epoxy resins, urea resins, resins having a triazine ring such as melamine resins, unsaturated polyester resins, bismaleimide resins, polyurethane resins, diallyl phthalate resins, silicone resins, resins having a benzoxazine ring, cyanate resins, polyimide resins, polyamideimide resins, benzocyclobutene resins, etc. Among these, epoxy resins are preferred.

[0067] This makes it possible to provide the insulating layer 10 with better heat resistance and a lower coefficient of thermal expansion.

[0068] Examples of epoxy resins include bisphenol type epoxy resins such as bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol E type epoxy resin, bisphenol S type epoxy resin, bisphenol M type epoxy resin (4,4'-(1,3-phenylenediisopridiene)bisphenol type epoxy resin), bisphenol P type epoxy resin (4,4'-(1,4-phenylenediisopridiene)bisphenol type epoxy resin), and bisphenol Z type epoxy resin (4,4'-cyclohexydienebisphenol type epoxy resin); phenol novolac type epoxy resin, cresol novolac type epoxy resin, and tetraphenol group ethane novolac type epoxy resin. Examples of epoxy resins include novolac-type epoxy resins such as silyl resins and novolac-type epoxy resins having a condensed ring aromatic hydrocarbon structure; biphenyl-type epoxy resins; aralkyl-type epoxy resins such as xylylene-type epoxy resins and biphenylaralkyl-type epoxy resins; naphthalene-type epoxy resins such as naphthylene ether-type epoxy resins, naphthol-type epoxy resins, naphthalenediol-type epoxy resins, difunctional to tetrafunctional naphthalene-type epoxy resins, binaphthyl-type epoxy resins, and naphthalenearalkyl-type epoxy resins; anthracene-type epoxy resins; phenoxy-type epoxy resins; dicyclopentadiene-type epoxy resins; norbornene-type epoxy resins; adamantane-type epoxy resins; and fluorene-type epoxy resins.

[0069] The resin composition 12 may contain a thermosetting resin other than an epoxy resin, or may use an epoxy resin and a thermosetting resin other than an epoxy resin in combination. As the thermosetting resin other than the epoxy resin, a cyanate resin is preferred.

[0070] The cyanate resin is a resin having a cyanate group (-O-CN) in the molecule, and a resin having two or more cyanate groups in the molecule can be used. Such a cyanate resin is not particularly limited, but can be obtained, for example, by reacting a halogenated cyanide compound with a phenol or naphthol, and optionally prepolymerizing it by heating or other methods. Alternatively, commercially available products prepared in this manner can also be used.

[0071] When the resin composition 12 contains a cyanate resin, the coefficient of thermal expansion of the insulating layer 10 can be more effectively reduced.

[0072] Examples of cyanate resins include novolac cyanate resins, bisphenol cyanate resins such as bisphenol A cyanate resin, bisphenol E cyanate resin, and tetramethylbisphenol F cyanate resin, naphthol aralkyl cyanate resins obtained by reacting naphthol aralkyl phenol resin with cyanogen halide, dicyclopentadiene cyanate resins, and biphenyl alkyl cyanate resins. Among these, novolac cyanate resins and naphthol aralkyl cyanate resins are preferred, and novolac cyanate resins are more preferred.

[0073] The inclusion of a novolac cyanate resin in the resin composition 12 increases the crosslink density of the insulating layer 10, improving its heat resistance. One reason for this is that the novolac cyanate resin forms a triazine ring after the curing reaction. Another reason is that the novolac cyanate resin has a high proportion of benzene rings in its structure, making it prone to carbonization. Furthermore, the inclusion of a novolac cyanate resin provides the insulating layer 10 with superior rigidity.

[0074] The content of the thermosetting resin in the resin composition 12 is preferably 5% by mass or more and 90% by mass or less, more preferably 10% by mass or more and 80% by mass or less, and even more preferably 20% by mass or more and 75% by mass or less.

[0075] This improves handling during manufacturing and makes it easier to realize the above-mentioned configuration of the present invention, allowing for a low thermal expansion coefficient and a higher level of adhesion between the insulating layer 10 and the metal layer 2.

[0076] [1-1-2-2] Inorganic filler Resin composition 12 contains an inorganic filler, which improves the mechanical strength and toughness of metal-clad laminate 1 and allows the thermal expansion coefficient of insulating layer 10 to be more appropriately adjusted.

[0077] Examples of inorganic fillers include silicates such as talc, calcined clay, uncalcined clay, mica, and glass; oxides such as titanium oxide, alumina, silica, and fused silica; carbonates such as calcium carbonate, magnesium carbonate, and hydrotalcite; hydroxides such as aluminum hydroxide, magnesium hydroxide, boehmite, and calcium hydroxide; sulfates or sulfites such as barium sulfate, calcium sulfate, and calcium sulfite; borates such as zinc borate, barium metaborate, aluminum borate, calcium borate, and sodium borate; nitrides such as aluminum nitride, boron nitride, silicon nitride, and carbon nitride; and titanates such as strontium titanate and barium titanate. One or more selected from these may be used in combination.

[0078] As the inorganic filler, those that generate a small amount of gas (vapor) when heated are preferred. As the inorganic filler, talc, boehmite, and silica are preferred, and silica (silica particles) is more preferred.

[0079] This makes it possible to improve the ease of availability, ease of surface treatment (good compatibility with silane coupling agents), and compatibility with other components due to the surface treatment.

[0080] Among silica particles, fused silica is preferred because it has a lower thermal expansion coefficient, and spherical fused silica is more preferred. The shape of the fused silica may be, for example, crushed or spherical, but spherical silica is preferred because it can sufficiently impregnate the glass cloth 11.

[0081] The average particle size of the inorganic filler is preferably 0.05 μm or more and 5.0 μm or less, more preferably 0.1 μm or more and 3.0 μm or less, and even more preferably 0.5 μm or more and 2.0 μm or less.

[0082] This prevents the resin composition 12 from becoming too viscous when it is in a varnish state before being impregnated into the glass cloth 11, improving workability during prepreg production and effectively preventing the inorganic filler from settling in the varnish, thereby enabling a more uniform prepreg to be obtained.

[0083] The inorganic filler may further contain nanosilica (particularly spherical nanosilica) having an average particle size of less than 100 nm. Such nanosilica can be present in the gaps between the inorganic filler particles having a larger particle size or in the strands of the glass cloth 11. This improves the adhesion between the insulating layer 10 and the metal layer 2 while further improving the filling efficiency of the inorganic filler.

[0084] The average particle size of the nanosilica is preferably less than 100 nm, more preferably 30 nm or more and 80 nm or less, and even more preferably 40 nm or more and 70 nm or less. This makes it possible to make the above-mentioned effects more pronounced.

[0085] The average particle size of the inorganic filler can be determined by measuring the particle size distribution of the particles on a volume basis using, for example, a laser diffraction particle size distribution analyzer (HORIBA, LA-500). The measurement is usually performed wet. When the concentration of the inorganic filler is high, the measurement is performed after appropriately diluting with methyl ethyl ketone or the like.

[0086] The content of the inorganic filler in the resin composition 12 is preferably 5% by mass or more and 40% by mass or less, more preferably 7% by mass or more and 38% by mass or less, and even more preferably 10% by mass or more and 35% by mass or less.

[0087] This allows the metal-clad laminate 1 to have a low thermal expansion coefficient and a higher level of adhesion between the insulating layer 10 and the metal layer 2, and also improves the formability when manufacturing the metal-clad laminate 1 by hot press molding.

[0088] [1-1-2-3] Coupling Agent The resin composition 12 may contain a coupling agent. The coupling agent may be mixed with the thermosetting resin and the inorganic filler when preparing the resin composition 12, or may be mixed with the inorganic filler in advance.

[0089] By including a coupling agent in the resin composition 12, the compatibility between the inorganic filler and other components is improved, the fluidity when heated is improved, and the adhesion between the insulating layer 10 and the metal layer 2 can be further improved.

[0090] Examples of the coupling agent include silane coupling agents such as epoxy silane coupling agents, cationic silane coupling agents, and amino silane coupling agents, titanate coupling agents, and silicone oil coupling agents, and one or more selected from these may be used in combination.

[0091] Among these, the silane coupling agent is preferred as the coupling agent. Various types of silane coupling agents can be used, including, for example, epoxy silane, amino silane, alkyl silane, ureido silane, mercapto silane, and vinyl silane.

[0092] Specific examples of the coupling agent include γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, N-β(aminoethyl)γ-aminopropyltrimethoxysilane, N-β(aminoethyl)γ-aminopropylmethyldimethoxysilane, N-phenylγ-aminopropyltriethoxysilane, N-phenylγ-aminopropyltrimethoxysilane, N-β(aminoethyl)γ-aminopropyltriethoxysilane, N-6-(aminohexyl)3-aminopropyltrimethoxysilane, and N-[3-

[0043] (trimethoxysilyl)propyl)-1,3-benzenedimethanane, γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, methyltrimethoxysilane, γ-ureidopropyltriethoxysilane, vinyltriethoxysilane, and the like, and one or more selected from these may be used in combination.

[0093] Among these, epoxysilane, mercaptosilane, and aminosilane are preferred, and as the aminosilane, primary aminosilane or anilinosilane is more preferred.

[0094] When the resin composition 12 contains a coupling agent, the content of the coupling agent in the resin composition 12 is preferably 0.01% by mass or more and 3% by mass or less, and more preferably 0.05% by mass or more and 1.5% by mass or less.

[0095] This makes it possible to more suitably proceed the reaction between the inorganic filler and the coupling agent while suppressing the coupling agent from adversely affecting the curing reaction of the thermosetting resin, thereby further improving compatibility with other components.

[0096] [1-1-2-4] Curing accelerator The resin composition 12 may contain a curing accelerator. This can improve the curability of the resin composition 12.

[0097] The curing accelerator is not particularly limited as long as it accelerates the curing reaction of the thermosetting resin. Examples of the curing accelerator include organic metal salts such as zinc naphthenate, cobalt naphthenate, tin octylate, cobalt octylate, zinc octylate, bisacetylacetonate cobalt (II), trisacetylacetonate cobalt (III), etc., tertiary amines such as triethylamine, tributylamine, diazabicyclo[2.2.2]octane, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 2-ethyl-4-ethylimidazole, 2-phenyl-4-methylimidazole, 2-ethyl-4-ethylimidazole, 2-phenyl-4-methylimidazole, 2-ethyl-4-ethylimidazole, 2-phenyl-4-methylimidazole, 2-ethyl-4-ethylimidazole, 2-ethyl-4-methyl ... Examples of the surfactant include imidazoles such as ethylimidazole, 2-phenyl-4-methyl-5-hydroxyimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, and 2-phenyl-4,5-dihydroxyimidazole; phenolic compounds such as phenol, bisphenol A, and nonylphenol; organic acids such as acetic acid, benzoic acid, salicylic acid, and paratoluenesulfonic acid; and onium salt compounds. One or more of these may be used in combination.

[0098] When the resin composition 12 contains a curing accelerator, the content of the curing accelerator in the resin composition 12 is preferably 0.01% by mass or more and 2.5% by mass or less, and more preferably 0.05% by mass or more and 1% by mass or less.

[0099] This makes it possible to enhance the storage stability of the resin composition 12 and further improve the curability of the resin composition 12.

[0100] [1-1-2-5] Other ingredients The resin composition 12 may contain components other than the above-mentioned components (hereinafter, also referred to as "other components" in this section).

[0101] Examples of other components include leveling agents, ultraviolet absorbers, dyes, pigments such as black pigments, stress reducing agents, antifoaming agents, surfactants, foaming agents, antioxidants, flame retardants, ion scavengers, etc., and one or more selected from these may be used in combination.

[0102] By using a leveling agent, for example, when producing a prepreg (when the resin composition 12 is impregnated into the glass cloth 11), repelling of the resin composition 12 can be suppressed, and the occurrence of surface defects can be more effectively suppressed.

[0103] Preferred examples of the leveling agent include (meth)acrylic leveling agents such as BYK361N, BYK350, BYK352, BYK354, BYK355, BYK356, BYK358N, BYK380N, BYK381, BYK392, and BYK394, all of which are manufactured by BYK Japan.

[0104] Examples of pigments include inorganic pigments such as kaolin, synthetic iron oxide red, cadmium yellow, nickel titanium yellow, strontium yellow, hydrous chromium oxide, chromium oxide, cobalt aluminate, and synthetic ultramarine blue; polycyclic pigments such as phthalocyanine; and azo pigments.

[0105] Examples of dyes include isoindolinone, isoindoline, quinophthalone, xanthene, diketopyrrolopyrrole, perylene, perinone, anthraquinone, indigoid, oxazine, quinacridone, benzimidazolone, violanthrone, phthalocyanine, and azomethine.

[0106] However, the content of other components in the resin composition 12 is preferably 10% by mass or less, more preferably 7% by mass or less, and even more preferably 5% by mass or less.

[0107] [1-1-2-6] Other conditions The proportion of the resin composition 12 in the insulating layer 10 is preferably 20% by mass or more and 45% by mass or less, more preferably 22.5% by mass or more and 42.5% by mass or less, and even more preferably 25% by mass or more and 40% by mass or less.

[0108] This allows the metal-clad laminate 1 to have a low thermal expansion coefficient and a higher level of adhesion between the insulating layer 10 and the metal layer 2, and also improves the formability when manufacturing the metal-clad laminate 1 by hot press molding.

[0109] [1-1-3] Other conditions The ash content in the insulating layer 10 is preferably 65% ​​or more and 87% or less, more preferably 67% or more and 85% or less, and even more preferably 70% or more and 83% or less.

[0110] This allows the metal-clad laminate 1 to have better formability when produced by hot press molding.

[0111] The ash content is the constituent components of the insulating layer 10 excluding organic compounds and moisture, and mainly includes the constituent components of the inorganic filler and the glass cloth 11 .

[0112] Specifically, the ash content is measured by a method in accordance with JIS K7250-(1)(2006).

[0113] [1-2] Metal layer Examples of materials that can be used for the metal layer 2 include copper, copper-based alloys, aluminum, aluminum-based alloys, silver, silver-based alloys, gold, gold-based alloys, zinc, zinc-based alloys, nickel, nickel-based alloys, tin, tin-based alloys, iron, and iron-based alloys.

[0114] As the metal layer 2, for example, a metal foil, a plated layer, a film formed by a vapor phase film deposition method, or the like can be used.

[0115] The thickness of the metal layer 2 is preferably 1 μm or more and 100 μm or less, and more preferably 2 μm or more and 40 μm or less.

[0116] [2] Manufacturing method for metal-clad laminates Next, a method for manufacturing a metal-clad laminate will be described. The metal-clad laminate 1 can be produced, for example, by a production method that appropriately combines known methods.

[0117] More specifically, it can be produced by the following method. That is, the metal-clad laminate 1 can be manufactured, for example, by a manufacturing method including: (i) a resin composition preparation step of preparing a varnish-like resin composition 12; and (ii) an impregnation step of impregnating the varnish-like resin composition 12 into glass cloth 11.

[0118] (i) The varnish-like resin composition 12 can be prepared by dissolving or dispersing the components of the resin composition 12 (thermosetting resin, inorganic filler, etc.) described above in an appropriate solvent.

[0119] The solvent includes an organic solvent. More specifically, examples of the solvent include acetone, methyl ethyl ketone, methyl isobutyl ketone, toluene, ethyl acetate, cyclohexane, heptane, cyclohexane, cyclohexanone, tetrahydrofuran, dimethylformamide, dimethylacetamide, dimethyl sulfoxide, ethylene glycol, cellosolve-based solvents, carbitol-based solvents, anisole, and N-methylpyrrolidone, and one or more selected from these may be used in combination.

[0120] When dissolving or dispersing each component in a solvent, various devices may be used, such as an ultrasonic disperser, a high-pressure collision type disperser, a high-speed rotation type disperser, a bead mill device, a high-speed shear type disperser, or a rotation-revolution type disperser.

[0121] The solid content concentration of the varnish-like resin composition 12 is preferably 30% by mass or more and 80% by mass or less, and more preferably 40% by mass or more and 70% by mass or less.

[0122] This can improve the workability and film-forming properties when the glass cloth 11 is impregnated with the varnish-like resin composition 12.

[0123] The method for impregnating the glass cloth 11 with the varnish-like resin composition 12 is not particularly limited, and examples thereof include a method of immersing the glass cloth 11 in the varnish-like resin composition 12, a method of applying the varnish-like resin composition 12 to the glass cloth 11 using various coaters, and a method of spraying the varnish-like resin composition 12 onto the glass cloth 11. Alternatively, the glass cloth 11 may be impregnated with the varnish-like resin composition 12 while applying an external force using a squeegee or the like. By performing the impregnation treatment while applying an external force, at least a portion of the inorganic filler is more likely to be present between the glass fibers that make up the glass cloth 11.

[0124] After impregnation, the prepreg can be obtained by removing the solvent through drying. The drying method and device are not particularly limited, and known methods such as hot air drying and infrared heating can be used.

[0125] The drying temperature is not particularly limited, but can be 80° C. or higher and 200° C. or lower, and the drying time is not particularly limited, but can be 1 minute or higher and 10 minutes or lower.

[0126] Thereafter, a plurality of the obtained prepregs are stacked to form a laminate, and metal films that form the metal layer 2 are overlaid on both the top and bottom surfaces of the laminate. Alternatively, the metal layer 2 may be formed on both the top and bottom surfaces of the laminate by plating or the like.

[0127] Next, the laminate and the metal foil are stacked together and then hot-press molded to form an insulating layer 10 made of a plurality of prepregs, thereby producing the metal-clad laminate 1.

[0128] The heating temperature during hot press molding is not particularly limited, but is preferably 120°C or higher and 220°C or lower, and more preferably 150°C or higher and 200°C or lower.

[0129] The pressure during hot press molding is not particularly limited, but is preferably 0.5 MPa or more and 5 MPa or less, and more preferably 1 MPa or more and 3 MPa or less.

[0130] If necessary, post-curing may be carried out at a temperature of 150° C. or higher and 300° C. or lower in a high-temperature bath or the like.

[0131] Here, it is preferable to laminate prepregs having a surface roughness of a predetermined value or less, so that when multiple prepregs are laminated and hot-press molded, adjacent glass cloths 11 can penetrate into the gaps between the uneven surfaces, and the metal-clad laminate 1 satisfying the above-mentioned configuration of the present invention can be more suitably manufactured.

[0132] The surface roughness Ra of the prepreg is preferably 0.01 μm or more and 8 μm or less, more preferably 0.1 μm or more and 6 μm or less, and even more preferably 0.3 μm or more and 5 μm or less. This makes it possible to make the above-mentioned effects more pronounced.

[0133] The method for producing the prepreg is not limited to the above-described method, and the prepreg may be produced by, for example, the following method. FIG. 3 is a diagram illustrating an example of a method for producing a prepreg.

[0134] First, as shown in Figures 3(a) and 3(b), a varnish-like resin composition 12 is applied to a substrate 20 made of polyethylene terephthalate (PET) or the like, and the solvent is dried by heating to produce a resin sheet with the substrate. Next, as shown in Figures 3(c) and 3(d), a glass cloth 11 is sandwiched between two resin sheets with the substrate and laminated, thereby impregnating the glass cloth 11 with the varnish-like resin composition 12. The lamination conditions can be, for example, 50°C or higher and 150°C or lower.

[0135] Thereafter, as shown in FIG. 3(e), the substrate 20 is peeled off to obtain a prepreg in which the glass cloth 11 is impregnated with the resin composition 12.

[0136] According to this method, even if the amount of the resin composition 12 is small, the occurrence of voids can be suppressed.

[0137] Furthermore, this method allows the surface of the resulting prepreg to be made smoother, making it easier to realize the above-described configuration of the present invention.

[0138] Then, similar to the method described above, multiple sheets of the obtained prepreg are stacked to form a laminate, and metal foil that forms the metal layer 2 is placed on both the top and bottom surfaces of the laminate, followed by hot press molding to produce the metal-clad laminate 1.

[0139] Although the preferred embodiments of the present invention have been described above, the present invention is not limited to these.

[0140] For example, the metal-clad laminate of the present invention is not limited to those produced by the above-mentioned production method.

[0141] Furthermore, for example, the method for producing a metal-clad laminate may further include other steps in addition to the steps described above. [Example]

[0142] The present invention will be described in more detail below with reference to specific examples, but the present invention is not limited to these examples. In the following description, treatments for which no temperature conditions are specified were performed at room temperature, specifically 25°C. Furthermore, various measurement conditions for which no temperature conditions are specified are values ​​at room temperature, specifically 25°C.

[0143] [3] Manufacturing of metal-clad laminates First, the materials used in manufacturing the metal-clad laminate are listed below.

[0144] <Resin composition> Epoxy resin: NC-3000 (Nippon Kayaku Co., Ltd., biphenyl aralkyl type epoxy resin) Cyanate resin: PT-30 (Lonza, novolac type cyanate resin) Phenolic resin: GPH-103 (Nippon Kayaku Co., Ltd., biphenyl aralkyl phenolic resin) Inorganic filler: SC2050 (spherical silica with an average particle size of 0.5 μm, manufactured by Admatechs Co., Ltd.) Coupling agent: A-187 (Momentive Performance Materials, epoxy silane coupling agent)

[0145] <Glass cloth> Glass cloth: #2118 (T glass, thickness 97 μm, 114 g / m 2 )

[0146] Example 1 Each material was dissolved or dispersed in methyl ethyl ketone at the solid content ratio shown in Table 1, and stirred using a high-speed stirrer to prepare a varnish-like resin composition with a nonvolatile content of 70 mass %.

[0147] Next, the varnish-like resin composition was applied to a PET film and heated at 120°C for 5 minutes to dry the solvent, producing a resin sheet with a PET substrate and a thickness of 19 μm. A glass cloth was sandwiched between two PET substrate-attached resin sheets and laminated at 110°C for 10 minutes, thereby impregnating the glass cloth with the resin composition. The PET film was peeled off to obtain a prepreg.

[0148] Ten sheets of the obtained prepreg were stacked to form a laminate, and 12 μm thick electrolytic copper foil was placed on the top and bottom of the laminate, and the laminate was subjected to a pressure of 40 kgf / cm 2 The resin was cured by hot press molding at 200°C for 90 minutes to obtain a double-sided metal-clad laminate.

[0149] The thickness of the insulating layer of the obtained double-sided metal-clad laminate, excluding the metal layer, was 830 μm, and the content of the resin composition in the insulating layer was 31 mass %.

[0150] (Examples 2 and 3) In preparing the resin composition, a metal-clad laminate was produced in the same manner as in Example 1, except that the blending ratio of each material was changed as shown in Table 1.

[0151] Example 4 In preparing the resin composition, the compounding ratio of each material was changed as shown in Table 1, the thickness of the resin composition of the resin sheet with PET substrate was changed to 25 μm, and the number of prepreg layers was changed. Except for this, a metal-clad laminate was produced in the same manner as in Example 1.

[0152] (Examples 5 to 6) In preparing the resin composition, the compounding ratio of each material was changed as shown in Table 1, the thickness of the resin composition of the resin sheet with PET substrate was changed to 16 μm, and the number of prepreg layers was changed. Except for this, a metal-clad laminate was produced in the same manner as in Example 1.

[0153] (Comparative Example 1) A metal-clad laminate was manufactured in the same manner as in Example 1, except that the number of prepregs was changed to 8, the thickness of the resin composition of the PET substrate-attached resin sheet was changed to 30 μm, and the number of prepregs stacked was changed.

[0154] (Comparative Example 2) In preparing the resin composition, a metal-clad laminate was produced in the same manner as in Comparative Example 1, except that the blending ratio of each material was changed as shown in Table 1.

[0155] [4] Evaluation The metal-clad laminates obtained in the above-mentioned Examples and Comparative Examples were evaluated as follows.

[0156] [4-1] Stacking structure The metal-clad laminates obtained in each of the examples and comparative examples were cut in the lamination direction of the glass cloth, in other words, in the thickness direction of the insulating layer, and the following dimensions were measured in cross section using a scanning electron microscope (SEM).

[0157] Fig. 4 is a cross-sectional SEM photograph of the metal-clad laminate of Example 1. Fig. 5 is a cross-sectional SEM photograph of the metal-clad laminate of Comparative Example 1.

[0158] When the thickness direction of the glass cloth is defined as the y direction and the direction perpendicular to the y direction is defined as the x direction, the y coordinate difference between the top and bottom of a first glass cloth having the maximum value at a predetermined x position among the multiple glass cloths was defined as a [μm].

[0159] At the x position, the center-to-center distance in the y direction between the first glass cloth and the second glass cloth adjacent to the first glass cloth was defined as b [μm].

[0160] Then, when the number of laminated glass cloths was c [sheets] and the thickness of the insulating layer was d [μm], the value of b / a and the relationship between a×c and d were evaluated.

[0161] [4-2] Void generation suppression The metal-clad laminates obtained in the above-mentioned respective Examples and Comparative Examples were cut in the lamination direction of the glass cloth, and the cross sections were observed for the presence or absence of voids, and evaluated according to the following criteria.

[0162] ◯: No voids were generated. ×: Voids were generated.

[0163] [4-3] Coefficient of thermal expansion (CTE) Test pieces of 6 mm x 6 mm were cut out from the metal-clad laminates obtained in the above-mentioned respective Examples and Comparative Examples, and the thermal expansion coefficients were measured as follows.

[0164] That is, using a TMA (thermal mechanical analysis) device (Q400, manufactured by TA Instruments), the thermal expansion coefficient (linear expansion coefficient in the x direction) was measured during the temperature rise process from 50°C to 100°C in the second cycle under conditions of a temperature range of 30°C to 300°C, a rate of 10°C / min, and a load of 5g, and was evaluated according to the following criteria.

[0165] ◯: The thermal expansion coefficient is less than 7.0 ppm / °C. △: The thermal expansion coefficient is 7.0 ppm / °C or more and less than 8.5 ppm / °C. ×: The thermal expansion coefficient is 8.5 ppm / °C or more.

[0166] FIG. 6 shows a graph showing the dimensional changes with temperature for the metal-clad laminates of Example 1 and Comparative Example 1.

[0167] [4-4] Adhesion For the metal-clad laminates obtained in each of the above examples and comparative examples, the peel strength of the metal layer from the insulating layer at 23°C was measured using a method in accordance with JIS C-6481:1996, and evaluated according to the following criteria.

[0168] ◯: Peel strength is 1.0 N / mm or more. △: Peel strength is 0.9 N / mm or more and less than 1.0 N / mm. ×: Peel strength is less than 0.9 N / mm.

[0169] [4-5] Moisture absorption solder heat resistance The metal-clad laminates obtained in each of the examples and comparative examples were cut to 50 mm x 50 mm using a grinder saw, and then double-sided etching was performed to prepare samples according to JIS C 6481. After leaving the samples in a constant temperature and humidity chamber at 30°C and 90% RH for 48 hours, the samples were immersed in a solder bath at 297°C, and after 60 seconds, the presence or absence of appearance abnormalities was observed and evaluated according to the following criteria.

[0170] 〇: No abnormalities. △: Slight swelling or peeling was observed. ×: A lot of swelling and peeling was observed overall. The evaluation results are summarized in Table 1.

[0171] [Table 1]

[0172] As is clear from Table 1, the present invention provided a metal-clad laminate that had both a low coefficient of thermal expansion and good adhesion between the insulating layer and the metal layer. In contrast, the comparative examples did not provide sufficient results.

[0173] In addition, metal-clad laminates were produced and evaluated in the same manner as in Example 1, except that the content of inorganic filler in the resin composition was changed in various ways within the range of 5% by mass or more and 40% by mass or less, and good results were obtained as described above.

[0174] In addition, metal-clad laminates were manufactured and evaluated in the same manner as in Example 1, except that the proportion of glass cloth in the insulating layer was variously changed within the range of 60 mass% or more and 75 mass% or less, and good results were obtained as described above.

[0175] In addition, metal-clad laminates were manufactured and evaluated in the same manner as in Example 1, except that the ash content in the insulating layer was changed in various ways within the range of 65% by mass or more and 87% by mass or less, and good results were obtained as described above. [Explanation of symbols]

[0176] 1:Metal-clad laminate 2: Metal layer 10: Insulating layer 11: Glass cloth 11a: First glass cloth 11b: Second glass cloth 12: Resin composition 20: Base material

Claims

1. A metal-clad laminate having an insulating layer comprising a plurality of glass cloths and a resin composition, and metal layers provided on both sides of the insulating layer, In a cross section in the thickness direction of the insulating layer, when the thickness direction of the glass cloth is defined as the y direction and the direction perpendicular to the y direction is defined as the x direction, Among the plurality of glass cloths, a first glass cloth has a maximum value of the y coordinate difference between the top and bottom at a predetermined x position, and the y coordinate difference is a [μm]; At the x position, the center-to-center distance in the y direction between the first glass cloth and the second glass cloth adjacent to the first glass cloth is b [μm], The number of laminated glass cloths is c [sheets], When the thickness of the insulating layer is d [μm], A metal-clad laminate characterized by satisfying the relationships b / a<1 and a×c>d.

2. The metal-clad laminate according to claim 1 , wherein the resin composition contains a thermosetting resin and an inorganic filler.

3. The metal-clad laminate according to claim 2 , wherein the content of the inorganic filler in the resin composition is 5% by mass or more and 40% by mass or less.

4. 4. The metal-clad laminate according to claim 1, wherein the insulating layer contains the glass cloth in an amount of 55% by mass or more and 80% by mass or less.

5. 4. The metal-clad laminate according to claim 1, wherein the insulating layer has an ash content of 65% or more and 87% or less.

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