JP2014141082A - Copper-clad laminate sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a copper-clad laminate sheet excellent in terms of the adhesiveness of a resin-impregnated sheet and a copper foil and the etching workability of the copper foil.SOLUTION: In the provided copper-clad laminate sheet, a copper foil is laminated on at least one surface of a resin-impregnated sheet obtained by impregnating a fiber sheet with a liquid crystal polyester, whereas the ten-point average roughness (Rz) of the surface of the copper foil contacted with the resin-impregnated sheet is 1.0-5.0 μm. It is desirable for the liquid crystal polyester to include repeating units expressed by the following formula (1), repeating units expressed by the following formula (2), and repeating units expressed by the following formula (3): (1) -O-Ar-CO-; (2) -CO-Ar-CO-; and (3) -X-Ar-Y- (Ardenotes a phenylene group, naphthylene group, or biphenylene group; Arand Arare independent of one another and each denote a phenylene group, naphthylene group, or biphenylene group; X and Y are independent of one another and each denote an oxygen atom or imino group).

Description

  The present invention relates to a copper clad laminate.

  As a printed wiring board, a printed wiring board having a resin-impregnated sheet and a wiring pattern provided thereon has been studied. This printed wiring board is obtained by patterning a copper foil from a copper-clad laminate having a resin-impregnated sheet and a copper foil provided thereon. And since it is excellent in heat resistance and dielectric loss is small as said resin impregnation sheet | seat, the resin impregnation sheet | seat by which a liquid crystal polyester is impregnated at the fiber sheet is examined (patent documents 1-5).

JP 2004-244621 A JP-A-2005-194406 JP 2006-1959 A JP 2006-278647 A JP 2007-146139 A

  The conventional copper-clad laminate does not necessarily have sufficient adhesion between the resin-impregnated sheet and the copper foil. For this reason, copper foil may be easily peeled off from the resin-impregnated sheet. Further, the conventional copper-clad laminate is not sufficiently etched. For this reason, when patterning copper foil by an etching, the unnecessary part of copper foil may remain easily. Then, the objective of this invention is providing the copper clad laminated board which is excellent in the adhesiveness of a resin impregnation sheet | seat and copper foil, and the etching workability of copper foil.

  In order to achieve the above object, the present invention provides a surface of the copper foil in which a copper foil is laminated on at least one surface of a resin-impregnated sheet in which a fiber sheet is impregnated with a liquid crystal polyester and is in contact with the resin-impregnated sheet. A copper clad laminate having a ten-point average roughness (Rz) of 1.0 to 5.0 μm is provided.

  The copper clad laminate of the present invention is excellent in the adhesion between the resin-impregnated sheet and the copper foil and the etching processability of the copper foil.

  The copper clad laminate of the present invention is a copper clad laminate in which a copper foil is laminated on at least one surface of a resin-impregnated sheet. The resin-impregnated sheet is a resin-impregnated sheet obtained by impregnating a fiber sheet with liquid crystal polyester.

  Examples of the fibers constituting the fiber sheet include inorganic fibers such as glass fibers, carbon fibers, and ceramic fibers; and organic fibers such as liquid crystal polyester fibers and other polyester fibers, aramid fibers, and polybenzazole fibers. Two or more kinds may be used. Of these, glass fiber is preferable. Examples of glass fibers include alkali-containing glass fibers, alkali-free glass fibers, and low dielectric glass fibers.

  The fiber sheet may be a woven fabric (woven fabric), a knitted fabric, or a non-woven fabric, but it is a woven fabric because the dimensional stability of the resin-impregnated sheet is easily improved. Is preferred. Examples of weaving methods include plain weaving, satin weaving, twill weaving and nanako weaving. The weaving density of the woven fabric is usually 10 to 100 pieces / 25 mm.

The thickness of the fiber sheet is usually 10 to 200 μm, preferably 10 to 180 μm. The mass per unit area of the fiber sheet is usually 10 to 300 g / m ² . The fiber sheet is preferably surface-treated with a coupling agent such as a silane coupling agent so as to improve the adhesion to the liquid crystal polyester.

  The liquid crystalline polyester is a polyester that exhibits liquid crystallinity in a molten state, and is preferably a liquid crystalline polyester that melts at a temperature of 450 ° C. or lower. The liquid crystal polyester may be a liquid crystal polyester amide, a liquid crystal polyester ether, a liquid crystal polyester carbonate, or a liquid crystal polyester imide. The liquid crystal polyester is preferably a wholly aromatic liquid crystal polyester using only an aromatic compound as a raw material monomer.

  A typical example of the liquid crystal polyester is polymerization (polycondensation) of an aromatic hydroxycarboxylic acid, an aromatic dicarboxylic acid, and at least one compound selected from the group consisting of an aromatic diol, an aromatic hydroxyamine, and an aromatic diamine. At least one selected from the group consisting of aromatic dicarboxylic acids and aromatic diols, aromatic hydroxyamines and aromatic diamines. Examples thereof include a liquid crystal polyester obtained by polymerizing a compound and a liquid crystal polyester obtained by polymerizing a polyester such as polyethylene terephthalate and an aromatic hydroxycarboxylic acid. Here, the aromatic hydroxycarboxylic acid, the aromatic dicarboxylic acid, the aromatic diol, the aromatic hydroxyamine, and the aromatic diamine are each independently replaced with a part or all of the polymerizable derivative. Also good.

  Examples of polymerizable derivatives of a compound having a carboxyl group such as aromatic hydroxycarboxylic acid and aromatic dicarboxylic acid include derivatives (esters) obtained by converting a carboxyl group into an alkoxycarbonyl group or an aryloxycarbonyl group, carboxyl Derivatives obtained by converting a group into a haloformyl group (acid halide) and derivatives obtained by converting a carboxyl group into an acyloxycarbonyl group (an acid anhydride) are included. Examples of polymerizable derivatives of hydroxyl group-containing compounds such as aromatic hydroxycarboxylic acids, aromatic diols and aromatic hydroxyamines include derivatives obtained by acylating hydroxyl groups and converting them into acyloxyl groups (acylated products) ). Examples of polymerizable derivatives of amino group-containing compounds such as aromatic hydroxyamines and aromatic diamines include derivatives (acylated products) obtained by acylating amino groups and converting them to acylamino groups.

  The liquid crystalline polyester preferably has a repeating unit represented by the following formula (1), a repeating unit represented by the following formula (2), and a repeating unit represented by the following formula (3).

(1) —O—Ar ¹ —CO—
(2) —CO—Ar ² —CO—
⁽³⁾ -X-Ar 3 -Y-

(Ar ¹ represents a phenylene group, a naphthylene group, or a biphenylylene group. Ar ² and Ar ³ each independently represent a phenylene group, a naphthylene group, a biphenylylene group, or a group represented by the following formula (4). X And Y each independently represents an oxygen atom or an imino group (—NH—), and each hydrogen atom in the group represented by Ar ¹ , Ar ² or Ar ³ independently represents a halogen atom or an alkyl group. Alternatively, it may be substituted with an aryl group.)

(4) -Ar ⁴ -Z-Ar ^5-

(Ar ⁴ and Ar ⁵ each independently represent a phenylene group or a naphthylene group. Z represents an oxygen atom, a sulfur atom, a carbonyl group, a sulfonyl group, or an alkylidene group.)

As said halogen atom, a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom are mentioned. Examples of the alkyl group include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, s-butyl group, t-butyl group, n-hexyl group, 2-ethylhexyl group, An n-octyl group and n-decyl group are mentioned, The carbon number is 1-10 normally. Examples of the aryl group include a phenyl group, an o-tolyl group, an m-tolyl group, a p-tolyl group, a 1-naphthyl group, and a 2-naphthyl group, and the number of carbon atoms is usually 6 to 20. . When the hydrogen atom is substituted with these groups, the number is usually 2 or less for each group represented by Ar ¹ , Ar ² or Ar ³ , and preferably 1 It is as follows.

  Examples of the alkylidene group include a methylene group, an ethylidene group, an isopropylidene group, an n-butylidene group, and a 2-ethylhexylidene group, and the number of carbon atoms is usually 1 to 10.

The repeating unit (1) is a repeating unit derived from a predetermined aromatic hydroxycarboxylic acid. The repeating unit (1) includes a repeating unit (1) in which Ar ¹ is a p-phenylene group (a repeating unit derived from p-hydroxybenzoic acid), and a repeating unit in which Ar ¹ is a 2,6-naphthylene group ( 1) (Repeating unit derived from 6-hydroxy-2-naphthoic acid) is preferred.

The repeating unit (2) is a repeating unit derived from a predetermined aromatic dicarboxylic acid. As the repeating unit (2), Ar ² is a p-phenylene group (2) (repeat unit derived from terephthalic acid), Ar ² is an m-phenylene group (2) (isophthalic acid) derived from repeating units), a repeating unit Ar ² is derived from the repeating unit (2) (2,6-naphthalenedicarboxylic acid is 2,6-naphthylene group), and Ar ² is diphenyl ether - ether-4,4 ' A repeating unit (2) which is a diyl group (a repeating unit derived from diphenyl ether-4,4′-dicarboxylic acid) is preferred.

The repeating unit (3) is a repeating unit derived from a predetermined aromatic diol, aromatic hydroxylamine or aromatic diamine. As the repeating unit (3), Ar ³ is a p-phenylene group (3) (a repeating unit derived from hydroquinone, p-aminophenol or p-phenylenediamine), and Ar ³ is 4,4′-. The repeating unit (3) which is a biphenylylene group (repeating unit derived from 4,4′-dihydroxybiphenyl, 4-amino-4′-hydroxybiphenyl or 4,4′-diaminobiphenyl) is preferred.

  The content of the repeating unit (1) is the total amount of all repeating units (the mass equivalent amount of each repeating unit (moles by dividing the mass of each repeating unit constituting the liquid crystal polyester by the formula amount of each repeating unit). ) And the total value thereof) is preferably 30 to 80 mol%, more preferably 30 to 60 mol%, still more preferably 30 to 40 mol%. The content of the repeating unit (2) is preferably 10 to 35 mol%, more preferably 20 to 35 mol%, still more preferably 30 to 35 mol%, based on the total amount of all repeating units. The content of the repeating unit (3) is preferably 10 to 35 mol%, more preferably 20 to 35 mol%, still more preferably 30 to 35 mol%, based on the total amount of all repeating units. The greater the content of the repeating unit (1), the easier it is to improve the heat resistance, strength and rigidity of the liquid crystal polyester. However, when the content is too large, the solubility in a solvent tends to be low.

  The ratio between the content of the repeating unit (2) and the content of the repeating unit (3) is expressed as [content of repeating unit (2)] / [content of repeating unit (3)] (mol / mol). The ratio is usually 0.9 / 1 to 1 / 0.9, preferably 0.95 / 1 to 1 / 0.95, and more preferably 0.98 / 1 to 1 / 0.98.

  In addition, liquid crystalline polyester may have 2 or more types of repeating units (1)-(3) each independently. Further, the liquid crystalline polyester may have a repeating unit other than the repeating units (1) to (3), but the content thereof is usually 10 mol% or less with respect to the total amount of all repeating units, preferably 5 mol% or less.

  The liquid crystalline polyester has a repeating unit (3) in which X and / or Y is an imino group as the repeating unit (3), that is, a repeating unit derived from a predetermined aromatic hydroxylamine and / or an aromatic diamine. Having the repeating unit derived from is preferable because it has excellent solubility in a solvent, and it is more preferable that the repeating unit (3) has only the repeating unit (3) in which X and / or Y is an imino group.

  The liquid crystal polyester is preferably produced by melt polymerization of raw material monomers corresponding to the repeating units constituting the liquid crystal polyester, and solid-phase polymerization of the obtained polymer (prepolymer). Thereby, high molecular weight liquid crystal polyester having high heat resistance, strength and rigidity can be produced with good operability. Melt polymerization may be carried out in the presence of a catalyst. Examples of this catalyst include metal compounds such as magnesium acetate, stannous acetate, tetrabutyl titanate, lead acetate, sodium acetate, potassium acetate, and antimony trioxide, And nitrogen-containing heterocyclic compounds such as 4- (dimethylamino) pyridine and 1-methylimidazole, and nitrogen-containing heterocyclic compounds are preferably used.

  The liquid polyester has a flow initiation temperature of usually 250 ° C. or higher, preferably 250 ° C. to 350 ° C., more preferably 260 ° C. to 330 ° C. As the flow start temperature is higher, the heat resistance, strength, and rigidity are more likely to be improved. However, if the flow start temperature is too high, the solubility in a solvent tends to be low, and the viscosity of the liquid composition tends to be high.

The flow start temperature is also called flow temperature or flow temperature, and the temperature is raised at a rate of 4 ° C./min under a load of 9.8 MPa (100 kg / cm ² ) using a capillary rheometer while the liquid crystalline polyester is used. Is a temperature showing a viscosity of 4800 Pa · s (48000 poise) when extruded from a nozzle having an inner diameter of 1 mm and a length of 10 mm, and is a measure of the molecular weight of the liquid crystal polyester (Naoki Koide, “Liquid Crystal Polymer— "Synthesis / Molding / Application-", CMC Co., Ltd., June 5, 1987, p. 95).

  The resin-impregnated sheet is preferably a resin-impregnated sheet in which a fiber sheet is further impregnated with an inorganic filler in addition to liquid crystal polyester. By including an inorganic filler in the resin-impregnated sheet, it is possible to obtain a resin-impregnated sheet imparted with performance such as low thermal expansion, thermal conductivity, dielectric property, and conductivity depending on the type.

  Examples of the inorganic filler include silica, alumina, zinc oxide, titanium oxide, tin oxide, aluminum nitride, boron nitride, silicon nitride, and silicon carbide, and two or more thereof may be used.

  As at least a part of the inorganic filler, an inorganic filler that has been surface-treated may be used in order to improve the adhesion to the liquid crystal polyester. Examples of surface treatment agents that can be used for this surface treatment include silane coupling agents, titanium coupling agents, aluminum coupling agents, zirconium coupling agents, long chain fatty acids, isocyanate compounds, and epoxy groups and methoxysilyl groups. And polymers having an amino group or a hydroxyl group.

  Content of an inorganic filler is 0-30 mass parts normally with respect to 100 mass parts of liquid crystalline polyester, Preferably it is 5-20 mass parts. If this ratio is too large, the adhesion between the resin-impregnated sheet and the copper foil is lowered.

  The resin-impregnated sheet may contain components other than liquid crystal polyester and inorganic filler, for example, resin other than liquid crystal polyester, organic filler, additives, etc. When plural types are included, the total is usually 0 to 10 parts by mass.

Examples of resins other than liquid crystal polyester include polypropylene, polyamide, polyester other than liquid crystal polyester, thermoplastic resin other than liquid crystal polyester such as polyphenylene sulfide, polyether ketone, polycarbonate, polyether sulfone, polyphenylene ether, polyether imide; and Thermosetting resins, such as a phenol resin, an epoxy resin, a polyimide resin, and cyanate resin, are mentioned. Examples of the organic filler include organic fillers such as a cured epoxy resin, a crosslinked benzoguanamine resin, and a crosslinked acrylic resin.
Examples of additives include leveling agents, antifoaming agents, antioxidants, ultraviolet absorbers, flame retardants, and colorants.

  The resin-impregnated sheet is preferably obtained by impregnating a fiber sheet with a liquid composition containing liquid crystal polyester and a solvent and then removing the solvent.

  As the solvent, a solvent that can dissolve the liquid crystal polyester to be used, specifically, a solvent that can be dissolved at a concentration of 1% by mass or more at 50 ° C. ([liquid crystal polyester] / [liquid crystal polyester + solvent]) is appropriately selected. Used.

  Examples of solvents include halogenated hydrocarbons such as dichloromethane, chloroform, 1,2-dichloroethane, 1,1,2,2-tetrachloroethane, o-dichlorobenzene; p-chlorophenol, pentachlorophenol, pentafluorophenol Halogenated phenols such as diethyl ether, tetrahydrofuran, 1,4-dioxane, etc .; ketones such as acetone and cyclohexanone; esters such as ethyl acetate and γ-butyrolactone; carbonates such as ethylene carbonate and propylene carbonate; amines such as triethylamine A nitrogen-containing heterocyclic aromatic compound such as pyridine; a nitrile such as acetonitrile or succinonitrile; an amide such as N, N-dimethylformamide, N, N-dimethylacetamide or N-methyl-2-pyrrolidone; Urea compounds such as tetramethylurea; nitro compounds such as nitromethane and nitrobenzene; sulfur compounds such as dimethyl sulfoxide and sulfolane; and phosphorus compounds such as hexamethylphosphoric acid amide and tri-n-butylphosphoric acid. More than one species may be used.

  As the solvent, since it is low in corrosivity and easy to handle, an aprotic compound, particularly a solvent mainly comprising an aprotic compound having no halogen atom, is preferred, and the proportion of the aprotic compound in the entire solvent is: Preferably it is 50-100 mass%, More preferably, it is 70-100 mass%, More preferably, it is 90-100 mass%. As the aprotic compound, amides such as N, N-dimethylformamide, N, N-dimethylacetamide, and N-methyl-2-pyrrolidone are preferably used because liquid crystalline polyester is easily dissolved.

  Moreover, as a solvent, since it is easy to melt | dissolve liquid crystalline polyester, the solvent which has a compound whose dipole moment is 3-5 as a main component is preferable, and the ratio of the compound whose dipole moment which occupies for the whole solvent is 3-5 Is preferably 50 to 100% by mass, more preferably 70 to 100% by mass, and still more preferably 90 to 100% by mass, and a compound having a dipole moment of 3 to 5 is used as the aprotic compound. Is preferred.

  Moreover, as a solvent, since it is easy to remove, the solvent which has as a main component the compound whose boiling point in 1 atmosphere is 220 degrees C or less is preferable, and the ratio of the compound whose boiling point in 1 atmosphere in the whole solvent is 220 degrees C or less is , Preferably 50 to 100% by mass, more preferably 70 to 100% by mass, still more preferably 90 to 100% by mass, and a compound having a boiling point of 220 ° C. or less at 1 atm is used as the aprotic compound. Is preferred.

  Content of the liquid crystal polyester in a liquid composition is 5-60 mass% normally with respect to the total amount of liquid crystal polyester and a solvent, Preferably it is 10-50 mass%, More preferably, it is 15-45 mass%, desired It adjusts suitably so that the liquid composition of this viscosity may be obtained.

  The liquid composition is preferably prepared by dispersing the inorganic filler and, if necessary, other components in a solution obtained by dissolving liquid crystal polyester and other components, if necessary, in a solvent. The inorganic filler may be dispersed in the solution while being pulverized by a ball mill, three rolls, a centrifugal stirrer, a bead mill or the like.

  After impregnating the fiber sheet with the liquid composition thus obtained, the resin-impregnated sheet can be obtained by removing the solvent. The removal of the solvent is preferably performed by evaporation of the solvent because the operation is simple, and examples of the method include heating, decompression and ventilation, and a combination of these.

  A copper clad laminate is obtained by laminating a copper foil on at least one surface of the resin-impregnated sheet thus obtained. And in this invention, the copper foil whose 10-point average roughness (Rz) of at least one surface is 1.0-5.0 micrometers is used as this copper foil, and this 10-point average roughness (Rz) is 1. Lamination is performed so that the surface of 0 to 5.0 μm is in contact with the resin-impregnated sheet. Thereby, the copper clad laminated board excellent in the adhesiveness of a resin impregnation sheet | seat and copper foil and the etching workability of copper foil can be obtained.

  The copper foil may have a 10-point average roughness (Rz) of both surfaces of 1.0 to 5.0 μm, or a 10-point average roughness (Rz) of only one surface of 1.0 to 5. Although it may be 0 μm, the ten-point average roughness (Rz) of one surface is 1.0 to 5.0 μm and the ten points of the other surface because of the ease of etching of the copper-clad laminate. The average roughness (Rz) is preferably 2.0 μm or less. The ten-point average roughness (Rz) of at least one surface of the copper foil is preferably 1.2 to 4.0 μm.

  Ten-point average roughness (Rz) is measured according to JIS C6515: 1998.

  The thickness of copper foil is 5-100 micrometers normally, Preferably it is 9-36 micrometers.

  The copper-clad laminate may be obtained by stacking a plurality of resin-impregnated sheets as necessary to form a laminated sheet and laminating a copper foil on at least one surface thereof. When a plurality of resin-impregnated sheets are stacked to form a laminated sheet, the plurality of resin-impregnated sheets may all be the same, only a part may be the same, or all may be different. The laminated sheet may be a laminated sheet obtained by laminating a plurality of resin-impregnated sheets with a hot press or the like.

  The lamination of the copper foil is usually performed by a hot press. When laminating copper foils on both sides of a resin-impregnated sheet or its laminated sheet by a hot press, the hot press is a press machine from both sides with a metal plate and a cushioning material arranged in this order on both copper foils, respectively. It is preferable to carry out by heating and pressurizing with a pair of heating plates. When a plurality of resin-impregnated sheets are laminated to form a laminated sheet and a copper foil is laminated on the laminated sheet, the copper-foil may be laminated on the resin-impregnated sheet at the same time as the resin-impregnated sheets are laminated by a hot press.

  Examples of metal plates include SUS plates and aluminum plates. Examples of the cushion material include a polybenzooxide (PBO) cushion, a carbon cushion, an alumina fiber nonwoven fabric cushion, and other inorganic fiber nonwoven fabric cushions.

  The copper-clad laminate thus obtained is excellent in adhesion between the resin-impregnated sheet and the copper foil and etching processability. Therefore, the copper foil can be suitably used as a printed wiring board by patterning the copper foil by etching or the like. it can.

[Measurement of flow start temperature of liquid crystalline polyester]
Using a flow tester (“CFT-500 type” manufactured by Shimadzu Corporation), about 2 g of liquid crystalline polyester was filled into a cylinder attached with a die having a nozzle having an inner diameter of 1 mm and a length of 10 mm, and 9.8 MPa (100 kg). The liquid crystal polyester was melted while being heated at a rate of 4 ° C./min under a load of / cm ² ), extruded from a nozzle, and a temperature showing a viscosity of 4800 Pa · s (48000 P) was measured.

[Measurement of viscosity of liquid composition]
Using a B-type viscometer (“TVL-20” from Toki Sangyo Co., Ltd.) The measurement was performed at a rotational speed of 5 rpm with 21 rotors.

[Measurement of 10-point average roughness (Rz) of copper foil surface]
It measured based on JIS C6515: 1998.

[Adhesion between resin-impregnated sheet and copper foil]
A 10 mm × 200 m sample is cut out from the copper clad laminate, the short side (10 mm side) of the copper foil is gripped, and the copper foil is pulled at a speed of 50 mm / min in the direction of 90 ° with respect to the surface of the sample. The sample was peeled off in the long side direction, and the peel strength of the copper foil was measured.

[Etching processability of copper-clad laminate]
A 10 mm × 200 m sample was cut out from the copper clad laminate, immersed in a ferric chloride aqueous solution (Kida Co., Ltd., 40 ° Baume) for 25 minutes, the copper foil was etched, and then washed with water. The obtained resin-impregnated sheet was sonicated in 36% by mass hydrochloric acid (2 mL), and then the copper residue in hydrochloric acid was quantified by ICP emission analysis.

〔Copper foil〕
As the copper foil, the following copper foil in which one surface was a rough surface and the other surface was a mirror surface was used.
Copper foil (1): Ten-point average roughness (Rz) of the rough surface is 1.4 μm, and the thickness is 18 μm.
Copper foil (2): Ten-point average roughness (Rz) of the rough surface is 3.6 μm, and the thickness is 18 μm.
Copper foil (3): Ten-point average roughness (Rz) of rough surface 0.7 μm, thickness 18 μm.
Copper foil (4): Ten-point average roughness (Rz) of rough surface 7.8 μm, thickness 18 μm.

Examples 1 and 2 and Comparative Examples 1 and 2
[Production of liquid crystalline polyester]
In a reactor equipped with a stirrer, a torque meter, a nitrogen gas introduction tube, a thermometer and a reflux condenser, 1976 g (10.5 mol) of 6-hydroxy-2-naphthoic acid and 1474 g (9.75 mol) of 4-hydroxyacetanilide were added. ), 1620 g (9.75 mol) of isophthalic acid and 2374 g (23.25 mol) of acetic anhydride, and after replacing the gas in the reactor with nitrogen gas, the mixture was stirred at room temperature to 150 ° C. under a nitrogen gas stream. The mixture was heated up to 15 minutes and refluxed at 150 ° C. for 3 hours. Next, while distilling off by-product acetic acid and unreacted acetic anhydride, the temperature was raised from 150 ° C. to 300 ° C. over 2 hours and 50 minutes, held at 300 ° C. for 1 hour, then the contents were taken out from the reactor, Cooled to room temperature. The obtained solid was pulverized with a pulverizer to obtain a powdery prepolymer. The flow initiation temperature of this prepolymer was 235 ° C. Next, this prepolymer was heated from room temperature to 223 ° C. over 8 hours and 10 minutes under a nitrogen atmosphere and held at 223 ° C. for 3 hours to solid-phase polymerize, then cooled, and powdered A liquid crystal polyester was obtained. The liquid crystal polyester had a flow start temperature of 270 ° C.

(Preparation of liquid composition)
2200 g of liquid crystal polyester was added to 7800 g of N-methyl-2-pyrrolidone and stirred at 100 ° C. for 2 hours in a nitrogen atmosphere to prepare a liquid crystal polyester solution. The viscosity of this liquid crystal polyester solution was 150 cP. Silica (“SFP-30M” manufactured by Denki Kagaku Kogyo Co., Ltd., volume average particle size 0.7 μm) is added to the liquid crystal polyester solution, and dispersed with a centrifugal defoamer (“HM-500” manufactured by Keyence Corporation). To obtain a liquid composition. The viscosity of this liquid composition was 420 cP. Here, the usage-amount of the silica was 8.1 mass% with respect to the total amount of liquid crystalline polyester and a silica.

[Production of resin impregnated sheet]
A glass cloth (glass cloth # 1078 manufactured by Unitika Co., Ltd.) is immersed in the liquid composition for 1 minute at room temperature, then the solvent is evaporated at 160 ° C. using a dryer, and then using a hot air dryer. In a nitrogen gas atmosphere, heat treatment was performed at 290 ° C. for 3 hours to obtain a resin-impregnated sheet.

[Manufacture of copper-clad laminate]
The copper foil shown in Table 1 is stacked on both surfaces of the resin-impregnated sheet so that the rough surface is in contact with the resin-impregnated sheet to form a laminated intermediate composed of the resin-impregnated sheet and the copper foil. SUS plate (SUS304 plate, Nippon Chemtech Co., Ltd., thickness 5 mm) and buffer material made of poly (paraphenylenebenzobisoxazole) (Ichikawa Technofabrics Co., Ltd., thickness 3 mm) Using a high-temperature vacuum press ("KVHC-PRESS", Kitakawa Seiki Co., Ltd., 300 mm long, 300 mm wide) at 340 ° C and 5 MPa, heating and pressing for 30 minutes under reduced pressure for integration for 30 minutes As a result, a copper clad laminate was obtained. The copper clad laminate was measured for the peel strength of the copper foil and the copper residue after the copper foil was etched, and the results are shown in Table 1.

Claims (4)

  A copper foil is laminated on at least one surface of a resin-impregnated sheet obtained by impregnating a fiber sheet with liquid crystal polyester, and the ten-point average roughness (Rz) of the surface of the copper foil in contact with the resin-impregnated sheet is 1. A copper clad laminate having a thickness of 0.0 to 5.0 μm. The liquid crystalline polyester has a repeating unit of 30 to 80 mol% represented by the following formula (1) and a repeating unit of 10 to 10 represented by the following formula (2) based on the total amount of all repeating units constituting the liquid crystalline polyester. The copper clad laminate according to claim 1, which is a liquid crystal polyester having 35 mol% and 10 to 35 mol% of repeating units represented by the following formula (3).
(1) —O—Ar ¹ —CO—
(2) —CO—Ar ² —CO—
⁽³⁾ -X-Ar 3 -Y-
(Ar ¹ represents a phenylene group, a naphthylene group, or a biphenylylene group. Ar ² and Ar ³ each independently represent a phenylene group, a naphthylene group, a biphenylylene group, or a group represented by the following formula (4). X And Y each independently represents an oxygen atom or an imino group, and each hydrogen atom in the group represented by Ar ¹ , Ar ² or Ar ³ is independently substituted with a halogen atom, an alkyl group or an aryl group. May be.)
(4) -Ar ⁴ -Z-Ar ^5-
(Ar ⁴ and Ar ⁵ each independently represent a phenylene group or a naphthylene group. Z represents an oxygen atom, a sulfur atom, a carbonyl group, a sulfonyl group, or an alkylidene group.)   The copper clad laminate according to claim 2, wherein X and / or Y is an imino group.   The copper clad laminate according to any one of claims 1 to 3, wherein the fiber sheet is further impregnated with an inorganic filler.