JP2013126778A - Multilayer fluororesin substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a substrate excellent in bonding to an insulating layer (fluororesin resin layer, resin layer) and an inorganic substrate, and excellent in the heat resistance, the flame retardancy, the dimensional stability, the electrical characteristic and the reliability in a severe environment of the high temperature and high humidity etc.SOLUTION: The multilayer fluororesin substrate is formed by laminating the multilayer fluororesin film obtained by laminating (A) fluororesin layer/(B) polyimide resin layer/(A) fluororesin layer in this order and the substrate that is selected from the group comprising the ceramic substrate, the glass substrate, and the semiconductor substrate. The multilayer fluororesin substrate has the peel strength of the multilayer fluororesin film and the substrate after the multilayer fluororesin substrate of 5 N/cm or more after heat-treated at 250°C for 24 hours.

Description

  The present invention relates to a multilayer substrate having a multilayer structure using an inorganic substrate such as a glass substrate, a ceramic substrate, or a semiconductor substrate as a core, and more specifically, an inorganic substrate such as a glass substrate, a ceramic substrate, or a semiconductor substrate and a polyimide film. The present invention also relates to a multilayer substrate for high frequency formed by forming an insulating layer by laminating via a thermoplastic fluororesin layer.

In general, in signal transmission in a high-frequency region, improvement in transmission speed and reduction in noise are required, and studies on substrate materials, wiring techniques, circuit configurations, and the like are also being made for printed circuits and antenna substrates.

  Conventionally, substrates used for printed circuits and antennas for high-frequency bands include reinforcing materials such as woven fabrics, non-woven fabrics, and papers made of glass fibers and aramid fibers, and fluororesins having the smallest dielectric constant among plastics. A composite sheet is known (see Patent Document 1). These substrates have a problem that it is difficult to ensure the adhesion between the reinforcing material and the fluororesin, and bubbles are easily formed at the interface, resulting in a lack of reliability. In addition, noise caused by spots on the reinforcing material has also been a problem. As a method for solving these problems, a substrate made of only a fluororesin has been disclosed (see Patent Document 2). However, the tensile strength and elongation, which are mechanical properties of fluororesin, are equivalent to polyolefin at room temperature. The linear expansion coefficient is 60 ppm / ° C. to 160 ppm / ° C. (see Non-Patent Document 1). For example, a glass substrate, ceramic substrate, or semiconductor substrate having a linear expansion coefficient of about 2.0 ppm / ° C. to 6.0 ppm / ° C. When laminated with an inorganic substrate such as the above, there was a great difference between the linear expansion coefficients of each other, and there was a risk of peeling during use or warping. Furthermore, as a method for solving these problems, there is an example in which a polyimide resin is laminated to suppress the linear expansion coefficient of the fluororesin (see Patent Documents 3 and 4) (see Non-Patent Document 2). However, since the linear expansion coefficient of the laminate obtained by this method is targeted for copper foil, it does not solve the above-described problems when laminated with an inorganic substrate.

JP 2003-171480 A Japanese Patent Laid-Open No. 07-038215 Japanese Patent Laying-Open No. 2005-310973 JP 2006-059865 A

"Fluorine resin handbook revised 11th edition", Japan Fluoropolymer Industry Association, P8-P15 "Printed Circuit Handbook 2nd Edition", Modern Science, P25-25 to P25-26

The present invention solves the above-mentioned problems, and is excellent in adhesion between an insulating layer (fluorine resin layer, polyimide resin layer) and an inorganic substrate even in harsh environments such as high temperature and high humidity, and has heat resistance, flame retardancy, and dimensional stability. An object of the present invention is to provide a substrate having excellent electrical characteristics and reliability.

That is, this invention is based on the following structure.
1. (A) Fluororesin layer / (B) Polyimide resin layer / (A) Fluororesin layer is laminated in this order, and is selected from the group consisting of a ceramic substrate, a glass substrate, and a semiconductor substrate. A multi-layer fluororesin substrate laminated with a substrate, wherein the multi-layer fluororesin substrate is heat-treated at 250 ° C. for 24 hours, and the peel strength between the multi-layer fluororesin film and the substrate is 5 N / cm or more. Multilayer fluororesin substrate.
2. 1. The linear expansion coefficient of the multilayer fluororesin film is 0 ppm / ° C. to 10 ppm / ° C. A multilayer fluororesin substrate as described in 1.
3. The multilayer fluororesin substrate according to claim 1 or 2, wherein the (A) layer is a layer of a functional group-containing thermoplastic fluororesin.
4). The multilayer fluororesin substrate according to any one of claims 1 to 3, wherein the layer (B) is a polyimide layer having a polyimide benzoxazole component and has a linear expansion coefficient of -10 ppm / ° C to 10 ppm / ° C.
5. The multilayer fluororesin substrate according to any one of claims 1 to 3, wherein the (A) layer has a thickness of 1.0 to 20 µm, and the (B) layer has a thickness of 1.0 to 75 µm.

The multilayer fluororesin film in which the (A) fluororesin layer / (B) polyimide resin layer / (A) fluororesin layer of the present invention is laminated in this order has a low linear expansion coefficient (multilayer fluororesin) which is a feature of the polyimide resin. As a film, it is a multilayer film that can achieve both a linear expansion coefficient equivalent to that of an inorganic substrate), high mechanical properties, a low dielectric constant and low water absorption, which are the characteristics of a fluororesin. In addition, since the deviation from the linear expansion coefficient of the inorganic substrate of 2 ppm / ° C. to 6 ppm / ° C. is small and the water absorption rate is low, warpage and distortion hardly occur even in an environment such as high temperature and high humidity. As a result, the quality of the printed circuit and the antenna board obtained as a result, and the production yield are also improved.
The multilayer substrate obtained by laminating the multilayer fluororesin film of the present invention and an inorganic substrate does not cause delamination at high temperatures and high humidity, and is excellent in heat resistance, flame retardancy, dimensional stability, electrical properties, and reliability. Very meaningful.

It is the schematic which shows an example of a comb-shaped pattern.

The present invention is described in detail below.
The (A) fluororesin layer used in the present invention is formed by applying a fluororesin film obtained by casting a fluororesin melt into a film, or applying the fluororesin melt to a polyimide resin layer (film). In view of handling and productivity, the form of a fluororesin film is preferable.
The fluororesin can be appropriately selected from conventionally known thermoplastic fluororesins used for general molding.
Examples of thermoplastic fluororesins include polymers or copolymers such as unsaturated fluorinated hydrocarbons, unsaturated fluorinated chlorinated hydrocarbons, ether group-containing unsaturated hydrocarbons, or these unsaturated fluorinated hydrocarbons. Examples include ethylene copolymers. Specific examples include polymers or copolymers of monomers selected from tetrafluoroethylene, chlorotrifluoroethylene, hexafluoropropylene, perfluoroalkyl vinyl ether), vinylidene fluoride and vinyl fluoride, or these monomers and Examples include ethylene copolymers.
More specific examples of thermoplastic fluororesin include tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer (PFA), tetrafluoroethylene / hexafluoropropylene copolymer (FEP), tetrafluoroethylene / hexafluoropropylene / per Fluoroalkyl vinyl ether copolymer (EPE), tetrafluoroethylene / ethylene copolymer (ETFE), polyvinylidene fluoride (PVDF), polychlorotrifluoroethylene (PCTFE), chlorotrifluoroethylene / ethylene copolymer (ECTFE) ) And the like.
Among these, from the viewpoints of heat resistance, flame retardancy, and electrical properties, tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer (PFA), tetrafluoroethylene / hexafluoropropylene copolymer (PFA), which is a copolymer of perfluorine ( FEP) and tetrafluoroethylene / hexafluoropropylene / perfluoroalkyl vinyl ether copolymer (EPE) are preferred.

The fluororesin is more preferably a functional group-containing thermoplastic fluororesin. When a thermoplastic fluororesin that does not contain a functional group is used, it is necessary to subject the polyimide film to surface treatment such as honing treatment, corona treatment, plasma treatment, ion gun treatment, and etching treatment in order to obtain adhesiveness that can withstand practical use. Therefore, the cost may increase.
The thermoplastic fluororesin containing a functional group includes a carboxylic acid group or a derivative group thereof, a hydroxyl group, a nitrile group, a cyanato group, a carbamoyloxy group, a phosphonooxy group, a halophosphonooxy group, a sulfonic acid group or a derivative group thereof, and a sulfo group. Mention may be made of thermoplastic fluororesins (functional group-containing fluororesins) containing functional groups selected from halide groups. Thus, as the functional group-containing fluororesin, a thermoplastic fluororesin usually used in the general molding is used in which the functional group is contained within a range that does not significantly impair the properties. In order to obtain such a functional group-containing fluororesin, for example, a thermoplastic fluororesin as shown in the above example used for general molding is synthesized and then introduced by adding or substituting these functional groups. Alternatively, it can be obtained by copolymerizing monomers having these functional groups during the synthesis of the thermoplastic fluororesin exemplified above.
Specific examples of the functional group include -COOH, -CH2COOH, -COOCH3, -CONH2, -OH, -CH2OH, -CN, -CH2O (CO) NH2, -CH2OCN, -CH2OP (O) (OH) 2,- Groups such as CH2OP (O) Cl2 and -SO2F can be exemplified. These functional groups are preferably introduced into the fluororesin by copolymerizing a fluorine-containing monomer having a functional group during the production of the fluororesin.

These monomers containing functional groups are preferably copolymerized in the functional group-containing fluororesin in an amount of 0.5 to 10% by weight, more preferably 1.0 to 5.0% by weight. Distribution of the functional group-containing monomer in the functional group-containing fluororesin may be uniform or non-uniform. If the content ratio of the functional group-containing monomer in the functional group-containing fluororesin is too small, the effect as a compatibilizer is small, while if the content ratio increases, the functional group-containing fluororesin resembles a cross-linking reaction due to strong interaction between the functional group-containing fluororesins. Reactions can occur and the viscosity can suddenly increase, making melt molding difficult. Moreover, when the content rate of a functional group containing monomer increases, there exists a tendency for the heat resistance of a functional group containing fluororesin to worsen.
There is no particular limitation on the viscosity or molecular weight of the functional group-containing fluororesin, but it is within the range not exceeding the viscosity or molecular weight of the thermoplastic fluororesin for general molding blended with these functional group-containing fluororesins, preferably the same. Good level.
The fluororesin preferably contains 0.1 to 2% by mass of an antistatic agent that imparts antistatic properties. As the antistatic agent, surfactants such as nonionic surfactants, anionic surfactants, cationic surfactants, and zwitterionic surfactants are preferable.

The fluororesin preferably contains an inorganic filler that lowers the dielectric constant and dielectric loss tangent. Inorganic fillers include silica, clay, talc, calcium carbonate, mica, diatomaceous earth, alumina, zinc oxide, titanium oxide, calcium oxide, magnesium oxide, iron oxide, tin oxide, antimony oxide, calcium hydroxide, magnesium hydroxide, water Aluminum oxide, basic magnesium carbonate, magnesium carbonate, zinc carbonate, barium carbonate, dosonite, hydrotalcite, calcium sulfate, barium sulfate, calcium silicate, montmorillonite, bentonite, activated clay, sepiolite, imogolite, sericite, glass fiber, glass Examples include beads, silica-based balloons, carbon black, graphite, carbon fibers, carbon balloons, wood powder, and zinc borate.
The inorganic filler may be used alone or in combination of two or more. As for content of an inorganic filler, 1-100 mass% is preferable with respect to a fluororesin. Further, it is preferable that these inorganic fillers are porous because the dielectric constant and dielectric loss tangent are further reduced.

The thickness of the fluororesin layer is preferably 1.0 μm to 25 μm, more preferably 1.0 μm to 20 μm, and still more preferably 1.0 μm to 17.5 μm. When the film thickness is larger than 25 μm, it is difficult to suppress the linear expansion coefficient to the same level as that of the inorganic substrate even if the polyimide resin layer is multilayered. On the other hand, a film thickness of less than 1.0 μm is not preferable because surface modification effects such as improvement of electrical characteristics, reduction of water absorption, and improvement of adhesiveness due to the fluororesin are reduced.
The storage elastic modulus: E ′ (A) of the fluororesin layer is not particularly limited, and it is known that a value of 0.3 GPa to 1.0 GPa is generally used when the fluororesin having the above composition is used.
Moreover, the linear expansion coefficient of the said fluororesin layer is not specifically limited, If it uses the fluororesin of the said composition, it will be generally taken as the value of 60 ppm / degrees C-160 ppm / degrees C.
Furthermore, it is preferable that the film has a small dielectric constant and dielectric loss tangent from the viewpoint of high frequency response. The dielectric constant and dielectric loss tangent of the fluororesin layer are not particularly limited, and it is known that generally low values are obtained when the fluororesin having the composition is used. Specifically, the dielectric constant at 1 MHz is 2.0 to 2.2, and the dielectric loss tangent at 1 MHz is 3.0 × 10 ^{−4 to} 5.0 × 10 ⁻⁴ .
The surface of the fluororesin layer is subjected to a treatment with a coupling agent (aminosilane, epoxysilane, etc.), a sand plast treatment, a rolling treatment, a corona treatment, a plasma treatment, an ion gun treatment, an etching treatment as necessary. Also good.

The (B) polyimide resin layer used in the present invention is composed of, for example, aromatic tetracarboxylic acids (anhydrides, acids, and amide bond derivatives are collectively referred to as classes below) and aromatic diamines (amines and amide bonds). A polyimide film obtained by a method of casting, drying, heat treatment (imidization) to form a film, and the polyamic acid solution. Is a layer formed by applying to a fluororesin layer (film), drying, and heat-treating (imidizing), and the form of polyimide film is preferable from the viewpoint of handling and productivity.
Hereinafter, the polyimide film will be mainly described in detail.
Although the said polyimide is not specifically limited, The combination of the following aromatic diamine and aromatic tetracarboxylic acid (anhydride) is mentioned as a preferable example.
A. Combination with aromatic tetracarboxylic acid having pyromellitic acid residue and aromatic diamine having benzoxazole structure.
B. A combination of an aromatic diamine having a phenylenediamine skeleton and an aromatic tetracarboxylic acid having a biphenyltetracarboxylic acid skeleton.
C. A combination of an aromatic diamine having a diphenyl ether skeleton and an aromatic tetracarboxylic acid having a pyromellitic acid residue.
In particular, A. A polyimide film having an aromatic diamine residue having a benzoxazole structure is preferred.

The molecular structure of the aromatic diamines having the benzoxazole structure is not particularly limited, and specific examples include the following. These diamines are preferably 70 mol% or more, more preferably 80 mol% or more of the total diamine.

  Among these, from the viewpoint of easy synthesis, each isomer of amino (aminophenyl) benzoxazole is preferable, and 5-amino-2- (p-aminophenyl) benzoxazole is more preferable. Here, “each isomer” refers to each isomer in which two amino groups of amino (aminophenyl) benzoxazole are determined according to the coordination position (eg, the above “formula 1” to “formula 4”). Each compound described in the above. These diamines may be used alone or in combination of two or more.

  Furthermore, as long as it is 30 mol% or less of the total diamine, one or more of the diamines exemplified below may be used in combination. Examples of such diamines include 4,4′-bis (3-aminophenoxy) biphenyl, bis [4- (3-aminophenoxy) phenyl] ketone, and bis [4- (3-aminophenoxy) phenyl]. Sulfide, bis [4- (3-aminophenoxy) phenyl] sulfone, 2,2-bis [4- (3-aminophenoxy) phenyl] propane, 2,2-bis [4- (3-aminophenoxy) phenyl] -1,1,1,3,3,3-hexafluoropropane, m-phenylenediamine, o-phenylenediamine, p-phenylenediamine, m-aminobenzylamine, p-aminobenzylamine, 3,3′-diamino Diphenyl ether, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether, 3,3'-dia Nodiphenyl sulfide, 3,3′-diaminodiphenyl sulfoxide, 3,4′-diaminodiphenyl sulfoxide, 4,4′-diaminodiphenyl sulfoxide, 3,3′-diaminodiphenyl sulfone, 3,4′-diaminodiphenyl sulfone, 4 , 4′-diaminodiphenylsulfone, 3,3′-diaminobenzophenone, 3,4′-diaminobenzophenone, 4,4′-diaminobenzophenone, 3,3′-diaminodiphenylmethane, 3,4′-diaminodiphenylmethane, 4, 4′-diaminodiphenylmethane, bis [4- (4-aminophenoxy) phenyl] methane, 1,1-bis [4- (4-aminophenoxy) phenyl] ethane, 1,2-bis [4- (4-amino) Phenoxy) phenyl] ethane, 1,1-bis [4- 4-aminophenoxy) phenyl] propane, 1,2-bis [4- (4-aminophenoxy) phenyl] propane, 1,3-bis [4- (4-aminophenoxy) phenyl] propane, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, 1,1-bis [4- (4-aminophenoxy) phenyl] butane, 1,3-bis [4- (4-aminophenoxy) phenyl] butane, , 4-bis [4- (4-aminophenoxy) phenyl] butane, 2,2-bis [4- (4-aminophenoxy) phenyl] butane, 2,3-bis [4- (4-aminophenoxy) phenyl ] Butane, 2- [4- (4-aminophenoxy) phenyl] -2- [4- (4-aminophenoxy) -3-methylphenyl] propane, 2,2-bis [4- (4-a Minophenoxy) -3-methylphenyl] propane, 2- [4- (4-aminophenoxy) phenyl] -2- [4- (4-aminophenoxy) -3,5-dimethylphenyl] propane, 2,2- Bis [4- (4-aminophenoxy) -3,5-dimethylphenyl] propane, 2,2-bis [4- (4-aminophenoxy) phenyl] -1,1,1,3,3,3-hexa Fluoropropane, 1,4-bis (3-aminophenoxy) benzene, 1,3-bis (3-aminophenoxy) benzene, 1,4-bis (4-aminophenoxy) benzene, 4,4′-bis (4 -Aminophenoxy) biphenyl, bis [4- (4-aminophenoxy) phenyl] ketone, bis [4- (4-aminophenoxy) phenyl] sulfide, bis [4- (4-amino) Enoxy) phenyl] sulfoxide, bis [4- (4-aminophenoxy) phenyl] sulfone, bis [4- (3-aminophenoxy) phenyl] ether, bis [4- (4-aminophenoxy) phenyl] ether, 1, 3-bis [4- (4-aminophenoxy) benzoyl] benzene, 1,3-bis [4- (3-aminophenoxy) benzoyl] benzene, 1,4-bis [4- (3-aminophenoxy) benzoyl] Benzene, 4,4′-bis [(3-aminophenoxy) benzoyl] benzene, 1,1-bis [4- (3-aminophenoxy) phenyl] propane, 1,3-bis [4- (3-aminophenoxy) ) Phenyl] propane, 3,4'-diaminodiphenyl sulfide, 2,2-bis [3- (3-aminophenoxy) phenyl -1,1,1,3,3,3-hexafluoropropane, bis [4- (3-aminophenoxy) phenyl] methane, 1,1-bis [4- (3-aminophenoxy) phenyl] ethane, 1 , 2-bis [4- (3-aminophenoxy) phenyl] ethane, bis [4- (3-aminophenoxy) phenyl] sulfoxide, 4,4′-bis [3- (4-aminophenoxy) benzoyl] diphenyl ether, 4,4′-bis [3- (3-aminophenoxy) benzoyl] diphenyl ether, 4,4′-bis [4- (4-amino-α, α-dimethylbenzyl) phenoxy] benzophenone, 4,4′-bis [4- (4-Amino-α, α-dimethylbenzyl) phenoxy] diphenylsulfone, bis [4- {4- (4-aminophenoxy) phenoxy} fe Sulfone, 1,4-bis [4- (4-aminophenoxy) phenoxy-α, α-dimethylbenzyl] benzene, 1,3-bis [4- (4-aminophenoxy) phenoxy-α, α-dimethyl Benzyl] benzene, 1,3-bis [4- (4-amino-6-trifluoromethylphenoxy) -α, α-dimethylbenzyl] benzene, 1,3-bis [4- (4-amino-6-fluoro) Phenoxy) -α, α-dimethylbenzyl] benzene, 1,3-bis [4- (4-amino-6-methylphenoxy) -α, α-dimethylbenzyl] benzene, 1,3-bis [4- (4 -Amino-6-cyanophenoxy) -α, α-dimethylbenzyl] benzene, 3,3′-diamino-4,4′-diphenoxybenzophenone, 4,4′-diamino-5,5′-dipheno Cibenzophenone, 3,4'-diamino-4,5'-diphenoxybenzophenone, 3,3'-diamino-4-phenoxybenzophenone, 4,4'-diamino-5-phenoxybenzophenone, 3,4'-diamino- 4-phenoxybenzophenone, 3,4'-diamino-5'-phenoxybenzophenone, 3,3'-diamino-4,4'-dibiphenoxybenzophenone, 4,4'-diamino-5,5'-dibiphenoxybenzophenone, 3,4′-diamino-4,5′-dibiphenoxybenzophenone, 3,3′-diamino-4-biphenoxybenzophenone, 4,4′-diamino-5-biphenoxybenzophenone, 3,4′-diamino-4 -Biphenoxybenzophenone, 3,4'-diamino-5'-biphenoxybenzophenone 1,3-bis (3-amino-4-phenoxybenzoyl) benzene, 1,4-bis (3-amino-4-phenoxybenzoyl) benzene, 1,3-bis (4-amino-5-phenoxybenzoyl) Benzene, 1,4-bis (4-amino-5-phenoxybenzoyl) benzene, 1,3-bis (3-amino-4-biphenoxybenzoyl) benzene, 1,4-bis (3-amino-4-bi) Phenoxybenzoyl) benzene, 1,3-bis (4-amino-5-biphenoxybenzoyl) benzene, 1,4-bis (4-amino-5-biphenoxybenzoyl) benzene, 2,6-bis [4- ( 4-amino-α, α-dimethylbenzyl) phenoxy] benzonitrile and some or all of the hydrogen atoms on the aromatic ring of the aromatic diamine are halogen atoms, An alkyl group having 1 to 3 carbon atoms, an alkoxyl group, a cyano group, or an alkyl group or an alkoxyl group having 1 to 3 carbon atoms in which some or all of the hydrogen atoms of the alkyl group or alkoxyl group are substituted with halogen atoms. Examples thereof include substituted aromatic diamines.

  The molecular structure of the aromatic tetracarboxylic acid anhydrides is not particularly limited, and specific examples include the following. These acid anhydrides are preferably 70 mol% or more, more preferably 80 mol% or more of the total acid anhydride.

These tetracarboxylic dianhydrides may be used alone or in combination of two or more.
Furthermore, as long as it is 30 mol% or less of the total tetracarboxylic dianhydrides, one or more of the non-aromatic tetracarboxylic dianhydrides exemplified below may be used in combination. Examples of such tetracarboxylic acid anhydrides include butane-1,2,3,4-tetracarboxylic dianhydride, pentane-1,2,4,5-tetracarboxylic dianhydride, and cyclobutanetetracarboxylic acid. Acid dianhydride, cyclopentane-1,2,3,4-tetracarboxylic dianhydride, cyclohexane-1,2,4,5-tetracarboxylic dianhydride, cyclohex-1-ene-2,3 5,6-tetracarboxylic dianhydride, 3-ethylcyclohex-1-ene-3- (1,2), 5,6-tetracarboxylic dianhydride, 1-methyl-3-ethylcyclohexane-3 -(1,2), 5,6-tetracarboxylic dianhydride, 1-methyl-3-ethylcyclohex-1-ene-3- (1,2), 5,6-tetracarboxylic dianhydride 1-ethylcyclohexane -(1,2), 3,4-tetracarboxylic dianhydride, 1-propylcyclohexane-1- (2,3), 3,4-tetracarboxylic dianhydride, 1,3-dipropylcyclohexane- 1- (2,3), 3- (2,3) -tetracarboxylic dianhydride, dicyclohexyl-3,4,3 ′, 4′-tetracarboxylic dianhydride, bicyclo [2.2.1] Heptane-2,3,5,6-tetracarboxylic dianhydride, 1-propylcyclohexane-1- (2,3), 3,4-tetracarboxylic dianhydride, 1,3-dipropylcyclohexane-1 -(2,3), 3- (2,3) -tetracarboxylic dianhydride, dicyclohexyl-3,4,3 ', 4'-tetracarboxylic dianhydride, bicyclo [2.2.1] heptane -2,3,5,6-tetracarboxylic dianhydride, bisic [2.2.2] Octane-2,3,5,6-tetracarboxylic dianhydride, bicyclo [2.2.2] oct-7-ene-2,3,5,6-tetracarboxylic dianhydride An anhydride etc. are mentioned.
Furthermore, a polyimide-silica hybrid (trade name: Composelane manufactured by Arakawa Chemical Industries, Ltd.) in which silica particles are nano-dispersed in polyimide may be used.

  The solvent used when reacting (polymerizing) the aromatic tetracarboxylic acid and the aromatic diamine to obtain a polyamic acid is particularly suitable as long as it can dissolve both the raw material monomer and the produced polyamic acid. Although not limited, polar organic solvents are preferred, such as N-methyl-2-pyrrolidone, N-acetyl-2-pyrrolidone, N, N-dimethylformamide, N, N-diethylformamide, N, N-dimethylacetamide, dimethyl Examples thereof include sulfoxide, hexamethylphosphoric amide, ethyl cellosolve acetate, diethylene glycol dimethyl ether, sulfolane, and halogenated phenols. These solvents can be used alone or in combination. The amount of the solvent used may be an amount sufficient to dissolve the monomer as a raw material. As a specific amount used, the weight of the monomer in the solution in which the monomer is dissolved is usually 5 to 40% by weight, The amount is preferably 10 to 30% by weight.

  Conventionally known conditions may be applied for the polymerization reaction for obtaining the polyamic acid (hereinafter also simply referred to as “polymerization reaction”). As a specific example, in a temperature range of 0 to 80 ° C., 10 Stirring and / or mixing continuously for minutes to 30 hours. If necessary, the polymerization reaction may be divided or the temperature may be increased or decreased. In this case, the order of adding both monomers is not particularly limited, but it is preferable to add aromatic tetracarboxylic acid anhydrides to the solution of aromatic diamines. The viscosity of the polyamic acid solution obtained by the polymerization reaction is preferably 10 to 2000 Pa · s, more preferably 100 to 1000 Pa · s from the viewpoint of the stability of liquid feeding as measured by a Brookfield viscometer (25 ° C.). It is.

Vacuum defoaming during the polymerization reaction is effective for producing a good quality polyamic acid solution. Moreover, you may perform superposition | polymerization by adding a small amount of terminal blockers to aromatic diamines before a polymerization reaction. Examples of the end capping agent include compounds having a carbon-carbon double bond such as maleic anhydride. The amount of maleic anhydride used is preferably 0.001 to 1.0 mol per mol of aromatic diamine.
In order to form a polyimide film from the polyamic acid solution obtained by the polymerization reaction, a green film (a self-supporting precursor film is obtained by applying the polyamic acid solution on a support and drying, then, Examples of the method of imidization reaction by subjecting the green film to heat treatment include, but are not limited to, application of the polyamic acid solution to the support, including casting from a slit-attached base and extrusion by an extruder. A conventionally known solution coating means can be appropriately used.

  The conditions for drying the polyamic acid coated on the support to obtain a green sheet are not particularly limited, and examples include a temperature of 70 to 150 ° C. and a drying time of 5 to 180 minutes. A conventionally known drying apparatus that satisfies such conditions can be applied, and examples thereof include hot air, hot nitrogen, far infrared rays, and high frequency induction heating. Next, in order to obtain a target polyimide film from the obtained green sheet, an imidization reaction is performed. As a specific method thereof, a conventionally known imidation reaction can be appropriately used. For example, there may be mentioned a method (so-called thermal ring closure method) in which an imidization reaction proceeds by subjecting it to a heat treatment after performing a stretching treatment as necessary using a polyamic acid solution containing no ring closure catalyst or a dehydrating agent. The heating temperature in this case is exemplified by 100 to 500 ° C. From the viewpoint of film physical properties, more preferably, a two-stage heat treatment in which the treatment is performed at 150 to 250 ° C. for 3 to 20 minutes and then treatment at 350 to 500 ° C. for 3 to 20 minutes. Is mentioned.

Another example of the imidization reaction is a chemical ring closure method in which a polyamic acid solution contains a ring closure catalyst and a dehydrating agent, and the imidization reaction is performed by the action of the ring closing catalyst and the dehydrating agent. In this method, after the polyamic acid solution is applied to the support, the imidization reaction is partially advanced to form a film having self-supporting property, and then imidization can be performed completely by heating. In this case, the condition for partially proceeding with the imidization reaction is preferably a heat treatment for 3 to 20 minutes at 100 to 200 ° C., and the condition for allowing the imidization reaction to be completely performed is preferably 200 to 400 ° C. For 3 to 20 minutes.

As for the thickness of the polyimide film which forms the said polyimide resin layer, 1.0 micrometer-75 micrometers are preferable, More preferably, they are 1.0 micrometer-60 micrometers, More preferably, they are 1.0 micrometer-50 micrometers. Thicknesses greater than 75 μm are not preferred for the purpose of reducing the weight of electronic components. Moreover, since the ratio of the polyimide with respect to the whole laminated body becomes high and exerts a bad influence on physical properties, such as a water absorption rate and an electrical property, it is unpreferable. On the other hand, if the film thickness is less than 1.0 μm, film formation is very difficult because the film is easily broken during conveyance and easily wrinkled.
The storage elastic modulus: E ′ (B) of the polyimide film forming the polyimide resin layer is not particularly limited, but is preferably 6.0 GPa or more, more preferably 7.0 GPa or more, and even more preferably 8.0 GPa or more. . If the tensile strength at break is less than 6 GPa, the effect of reinforcing the fluororesin layer by the polyimide film may not be obtained.
The linear expansion coefficient of the polyimide film forming the polyimide resin layer is preferably −10 ppm / ° C. to 10 ppm / ° C., more preferably −7.5 ppm / ° C. to 7.5 ppm / ° C., more preferably − 5 ppm / ° C to 5 ppm / ° C. If the linear expansion coefficient exceeds this range, distortion and wrinkles may occur during high temperature exposure such as soldering.
For the polyimide film forming the polyimide resin layer, treatment with a coupling agent (aminosilane, epoxysilane, etc.), sandplast treatment, rolling treatment, corona treatment, plasma treatment, ion gun treatment, etching treatment, etc. You may use for.

In the present invention, the coefficient of linear expansion of the multilayer fluororesin film is preferably 0 ppm / ° C. to 10 ppm / ° C., more preferably 0 ppm / ° C. to 9.0 ppm / ° C., further preferably 0 ppm / ° C. to 8.0 ppm / ° C. ° C. When the linear expansion coefficient exceeds this range, the mutual linear expansion coefficient when laminated with an inorganic substrate such as a glass substrate, ceramic substrate, or semiconductor substrate having a linear expansion coefficient of 2.0 ppm / ° C. to 6.0 ppm / ° C. There is a risk of peeling off during use, and there is a risk of warping.
In order to set the linear expansion coefficient of the multilayer fluororesin film within the range of 0 ppm / ° C. to 10 ppm / ° C., the thickness ratio of the (A) layer in the multilayer fluororesin film {total (A) layer / multilayer fluororesin film} 1.0% to 35%, and the storage elastic modulus of the layer (A) at room temperature: E ′ (A) and the storage elastic modulus of the layer (B) at room temperature: E ′ (B) ratio { E ′ (A) / E ′ (B)} is preferably 2.0% to 20%, more preferably the thickness ratio is 5.0% to 35%, and the storage modulus ratio is 2.5. % To 15%, more preferably the thickness ratio is 10% to 35%, and the storage modulus ratio is 3.0% to 10%. By setting the thickness ratio or the storage elastic modulus ratio within this range, a multilayer fluororesin film having a target linear expansion coefficient can be obtained.

The method for laminating the multilayer fluororesin substrate used in the present invention is not particularly limited.
(1) Method of arranging fluororesin film / polyimide film / fluororesin film / inorganic substrate and laminating by hot pressing
(2) A multilayer fluororesin film obtained by a coextrusion method, a method of casting a fluororesin on a polyimide film, a method of casting a fluororesin on a precursor film of a polyimide film and imidizing, etc. Method of laminating by hot pressing with substrate
(3) A method of laminating a polyimide film by hot pressing after providing a fluororesin on an inorganic substrate
Etc.

Examples of the inorganic substrate having a linear expansion coefficient of 0 ppm / ° C. to 10 ppm / ° C. used in the present invention include a glass substrate, a ceramic substrate, and a semiconductor substrate.
As the glass substrate, a conventionally known glass substrate can be used, for example, a glass made of soda lime glass, soda potassium glass, soda aluminum silicate glass, alumino borosilicate glass, aluminoborosilicate glass, low expansion glass, quartz glass or the like. Is mentioned. Further, a glass substrate may be provided with through holes, conductor circuits, resistors, inductors, and capacitors.

As the ceramic substrate, conventionally known ceramic substrates can be used, for example, ceramics such as alumina, zirconia, mullite, cordierite, steatite, magnesium titanate, calcium titanate, strontium titanate, aluminum nitride, silicon carbide, silicon nitride and the like. The thing which becomes. A ceramic substrate may be provided with through holes, conductor circuits, resistors, inductors, and capacitors.

As the semiconductor substrate, a conventionally known semiconductor substrate represented by a silicon wafer can be used. For example, elemental systems such as a silicon (Si) wafer, germanium (Ge), selenium (Se), tin (Sn), and tellurium (Te). Semiconductors or semiconductors such as gallium arsenide (GeAs), GaP, GaSb, AlP, AlAs, AlSb, InP, InAs, InSb, ZnS, ZnSe, ZnTe, CdS, CdSe, CdTe, AlGaAs, GaInAs, AlInAs, AlGaInAs, etc. Is mentioned. Further, a semiconductor substrate may be provided with through holes, conductor circuits, resistors, inductors, and capacitors.

The metal used as the conductor of the present invention is not particularly limited, but silver, copper, gold, platinum, rhodium, nickel, aluminum, iron, chromium, zinc, tin, brass, white copper, bronze, monel, molybdenum, Tungsten, tin-lead solder, tin-copper solder, tin-silver solder, or the like alone or an alloy thereof is used. In particular, the use of copper is a preferred embodiment in terms of the balance between performance and economy.

EXAMPLES Hereinafter, although an Example and a comparative example are shown and this invention is demonstrated more concretely, this invention is not limited by a following example. In addition, the evaluation method of the physical property in the following examples is as follows.

1. Reduced viscosity (ηsp / C)
A solution dissolved in N-methyl-2-pyrrolidone (or N, N-dimethylacetamide) so that the polymer concentration was 0.2 g / dl was measured at 30 ° C. with an Ubbelohde type viscosity tube.

2. Thickness The film to be measured was measured using a micrometer (Minetron 1245D, manufactured by Finelfu).

3. About the film | membrane of storage elastic modulus measurement object, viscoelasticity measurement (DMA) was performed on the following conditions, and the value of storage elastic modulus: E 'in 25 degreeC was calculated | required.
Device name: Rheogel-E4000 manufactured by UBM
Jig: Stretch jig
Sample length: 14mm
Sample width: 5 mm
Frequency: 10Hz
Temperature rise start temperature: 0 ° C
Temperature increase rate: 5 ° C / min
Atmosphere: Nitrogen

4). Linear expansion coefficient (CTE)
For the film to be measured, the stretch rate in the MD direction and the TD direction is measured under the following conditions, and the stretch rate / temperature at intervals of 90 to 100 ° C., 100 to 110 ° C.,. Was performed up to 400 ° C., and the average value of all measured values from 100 ° C. to 300 ° C. was calculated as CTE (average value).
Device name: TMA4000S manufactured by MAC Science
Sample length: 10mm
Sample width: 2mm
Temperature rise start temperature: 25 ° C
Temperature rise end temperature: 400 ° C
Temperature increase rate: 5 ° C / min
Atmosphere: Argon

5. The film to be measured was subjected to differential scanning calorimetry (DSC) under the following conditions, and the melting point (Tm) was determined according to JIS K7121.
Device name: DSC3100S manufactured by MAC Science
Bread: Aluminum bread (non-airtight type)
Sample mass: 4mg
Temperature rising start temperature: 30 ° C
Temperature rise end temperature: 400 ° C
Temperature increase rate: 20 ° C / min
Atmosphere: Argon

6). A fluororesin film to be measured for dielectric constant and dielectric loss tangent was cut into a size of 3 mm (thickness) × 200 mm × 120 mm to prepare a test film. Conductive paste was applied to both sides of the test film and wired, and the dielectric constant and dielectric loss tangent at 1 MHz were measured.

7). Peel strength The peel strength between the multilayer fluororesin film / inorganic substrate was determined by performing a 180 ° peel test under the following conditions.
Device name: Autograph AG-IS, manufactured by Shimadzu Corporation
Sample length: 100mm
Sample width: 10mm
Measurement temperature: 25 ° C
Peeling speed: 50mm / min
Atmosphere: Atmosphere

<< Evaluation of Substrate >> Each multi-layer fluororesin substrate composed of a moisture and heat-resistant multi-layer fluororesin film / inorganic substrate is treated under JEDEC LEVEL 1 conditions (85 ° C./85% RH-168 hr + 245 ° C./3 sec × 3 times) and after the test. The peel strength was evaluated. In addition, in the appearance inspection after the test, the case where peeling, blistering, or discoloration was not observed was indicated as “◯”, the case where peeling, blistering, or discoloration was slightly observed was indicated as Δ, and the case where peeling, blistering, or discoloration was observed was indicated as “X”.

<< Evaluation of Substrate >> Each multi-layer fluororesin substrate composed of a heat-resistant multi-layer fluororesin film / inorganic substrate is placed in a stainless mesh cage and subjected to heat treatment at 250 ° C. for 24 hours in the atmosphere to evaluate the peel strength after the test. did. In addition, in the appearance inspection after the test, the case where peeling, blistering, or discoloration was not observed was indicated as “◯”, the case where peeling, blistering, or discoloration was slightly observed was indicated as Δ, and the case where peeling, blistering, or discoloration was observed was indicated as “X”.

<< Evaluation of Substrate >> A voltage (DC 60 V) is applied to each test multi-layer fluororesin substrate composed of a multi-layer fluororesin film / inorganic substrate on which a comb-shaped pattern (FIG. 1) having a migration resistance of 40 μm pitch is formed. Put it in a constant temperature and humidity chamber of% RH (FX412P type, manufactured by ETAC) and measure the insulation resistance value every 5 minutes with the voltage loaded, and measure the time until the resistance value between lines reaches 100M ohm or less. , 1000 hours or more were evaluated as ○, and less than 1000 hours as ×.

[Production Example 1]
(Preparation of polyimide film A)
The inside of the reaction vessel equipped with a nitrogen introduction tube, a thermometer, and a stirring rod was purged with nitrogen, and then 223 parts by mass of 5-amino-2- (p-aminophenyl) benzoxazole and 4416 parts by mass of N, N-dimethylacetamide were added. 40.5 parts by mass of Snowtex (DMAC-ST30, manufactured by Nissan Chemical Industries, Ltd.) (containing 8.1 parts by mass of silica), pyromellitic acid, which is prepared by completely dissolving the colloidal silica in dimethylacetamide. When 217 parts by mass of dianhydride was added and stirred for 24 hours at a reaction temperature of 25 ° C., a brown and viscous polyamic acid solution A was obtained. This reduced viscosity was 3.9 dl / g.
This polyamic acid solution A was coated on a non-lubricant surface of polyethylene terephthalate film A-4100 (manufactured by Toyobo Co., Ltd.) using a comma coater, dried at 110 ° C. for 5 minutes, and then not peeled off from the support. The polyamic acid film was wound up. The polyamic acid film is passed through a pin tenter having three heat treatment zones, the first stage 150 ° C. × 2 minutes, the second stage 220 ° C. × 2 minutes, the third stage 475 ° C. × 4 minutes, and 20 minutes after passing through the tenter. Six rolls were passed to give a double-sided free process, and finally slit to 500 mm width to obtain polyimide films A1 to A3.
Table 1 shows the physical property values of the obtained polyimide films A1 to A3.

[Production Example 2]
(Preparation of polyimide film B)
After the inside of the reaction vessel equipped with a nitrogen introduction tube, a thermometer, and a stirring rod was purged with nitrogen, 200 parts by mass of diaminodiphenyl ether and 4170 parts by mass of N-methyl-2-pyrrolidone were added and completely dissolved, and then colloidal silica was added. 40.5 parts by mass of Snowtex (DMAC-ST30, manufactured by Nissan Chemical Industries, Ltd.) dispersed in dimethylacetamide (containing 8.1 parts by mass of silica), 217 parts by mass of pyromellitic dianhydride were added, and 25 ° C. When the mixture was stirred at the reaction temperature of 5 hours, a brown viscous polyamic acid solution B was obtained. This reduced viscosity was 3.6 dl / g.
This polyamic acid solution B was coated on a non-lubricant surface of polyethylene terephthalate film A-4100 (manufactured by Toyobo Co., Ltd.) using a comma coater, dried at 110 ° C. for 5 minutes, and then not peeled off from the support. The polyamic acid film was wound up. The polyamic acid film is passed through a pin tenter having three heat treatment zones, the first stage is 150 ° C. × 2 minutes, the second stage is 220 ° C. × 2 minutes, the third stage is 400 ° C. × 4 minutes, and 20 minutes after passing through the tenter. Six rolls were passed to give a double-side free process, and finally slit to 500 mm width to obtain polyimide film B.
Table 1 shows the physical property values of the obtained polyimide film B.

[Production Example 3]
(Preparation of polyimide film C)
After the inside of the reaction vessel equipped with a nitrogen introduction tube, a thermometer, and a stirring rod was replaced with nitrogen, 108 parts by mass of phenylenediamine and 4010 parts by mass of N-methyl-2-pyrrolidone were added and completely dissolved, and then colloidal silica was added. Snowtex (DMAC-ST30, manufactured by Nissan Chemical Industries, Ltd.) 40.5 parts by mass (including 8.1 parts by mass of silica) dispersed in dimethylacetamide and 292.5 parts by mass of diphenyltetracarboxylic dianhydride In addition, when the mixture was stirred at a reaction temperature of 25 ° C. for 12 hours, a brown viscous polyamic acid solution C was obtained. This reduced viscosity was 4.3 dl / g.
This polyamic acid solution C was coated on a non-lubricant surface of polyethylene terephthalate film A-4100 (manufactured by Toyobo Co., Ltd.) using a comma coater, dried at 110 ° C. for 5 minutes, and then not peeled off from the support. The polyamic acid film was wound up. The polyamic acid film is passed through a pin tenter having three heat treatment zones, the first stage is 150 ° C. × 2 minutes, the second stage is 220 ° C. × 2 minutes, the third stage is 460 ° C. × 4 minutes, and 20 minutes after passing through the tenter. Six rolls were passed to give a double-side free process, and finally slit to a width of 500 mm to obtain a polyimide film C having a thickness of 25 μm.
Table 1 shows the physical property values of the obtained polyimide film C.

[Production Example 4]
(Create fluororesin film)
Using a commercially available fluororesin, a fluororesin film was prepared by a conventionally known method.
The types and physical properties of the obtained fluororesin film are shown in Tables 2 and 3.

[Example 1]
A functional group-containing fluororesin film D2 is arranged on both sides of a polyimide film A1 cut into a size of 150 mm × 150 mm, and heat-pressure molding is performed for 30 minutes at 330 ° C. and 5 MPa, which is higher than the melting point of the fluororesin film. A resin film was obtained. Table 4 shows the evaluation results of the thickness ratio, storage elastic modulus ratio, and linear expansion coefficient of the obtained multilayer fluororesin film.
On the other hand, a functional group-containing fluororesin film D2 is provided on one surface of a polyimide film A1 cut into a size of 150 mm × 150 mm, a functional group-containing fluororesin film D2 and a glass substrate (product name: 1737, manufactured by Corning) on the other surface. Glass, thickness 1.0 mm, linear expansion coefficient 3.0 ppm / ° C.) are arranged in this order, and heat-pressure molding is performed for 30 minutes at 330 ° C. and 5 MPa which is equal to or higher than the melting point of the fluororesin film. Got. Table 4 shows the evaluation results of the heat resistance and heat resistance of the obtained multilayer fluororesin substrate.
Furthermore, a functional group-containing fluororesin film D2 and a 9 μm-thick copper foil (UWZ, manufactured by Furukawa Circuit Foil Co., Ltd.) are provided on one side of the polyimide film A1 cut into a size of 150 mm × 150 mm, and a functional group-containing fluorine is provided on the other side. A resin film D2 and a glass substrate (manufactured by Corning, trade name: 1737 glass, thickness 1.0 mm, linear expansion coefficient 3.0 ppm / ° C.) are arranged in this order, and 330 ° C. which is equal to or higher than the melting point of the fluororesin film, Heat-press molding was performed at 5 MPa for 30 minutes to obtain a copper-bonded multilayer fluororesin substrate.
Next, pattern formation was performed. A photoresist (FR-200, manufactured by Shipley Co., Ltd.) was applied and dried on the copper surface of the copper-coated multilayer fluororesin substrate, and then contacted and exposed with a glass photomask, and further developed with a 1.2 mass% KOH aqueous solution. Next, etching is performed with a cupric chloride etching line containing HCl and hydrogen peroxide at a spray pressure of 40 ° C. and 2 kgf / cm ² , and a “comb pattern” as shown in FIG. 1 is necessary for the evaluation test. The conductor width and conductor spacing were 40 μm / 40 μm, and the number of patterns was 20 test patterns on one side, followed by washing and annealing at 125 ° C. for 1 hour to obtain a test multilayer fluororesin substrate. Table 4 shows the evaluation results of migration resistance of the obtained test multilayer fluororesin substrate.

[Example 2]
A laminate was prepared and evaluated in the same manner as in Example 1 except that polyimide film A2 was used instead of polyimide film A1. The evaluation results are shown in Table 4.

[Examples 3 and 4]
A laminate was prepared and evaluated in the same manner as in Examples 1 and 2 except that the functional group-containing fluororesin film D3 was used instead of the functional group-containing fluororesin film D2. The evaluation results are shown in Table 4.

Example 5
A laminate was prepared and evaluated in the same manner as in Example 1 except that the functional group-containing fluororesin film D1 was used instead of the functional group-containing fluororesin film D2. The evaluation results are shown in Table 4.

Example 6
Lamination was performed in the same manner as in Example 1 except that a ceramic substrate (manufactured by Nippon Carbide Industries Co., Ltd., trade name: alumina ceramic, thickness 1.0 mm, linear expansion coefficient 6.0 ppm / ° C.) was used instead of the glass substrate. A body was created and evaluated. The evaluation results are shown in Table 5.

Example 7
A laminate was prepared and evaluated in the same manner as in Example 1 except that a silicon wafer (diameter: about 100 mm, thickness: 0.25 mm, linear expansion coefficient: 2.0 ppm / ° C.) was used instead of the glass substrate. The evaluation results are shown in Table 5. The multilayer fluororesin film was laminated so as to be in contact with the mirror surface of the silicon wafer.

[Examples 8 to 11]
The polyimide film A1 cut out to A4 size is set in a plasma treatment machine made by Nikketsu Co., Ltd., and vacuum treatment is performed under the conditions of vacuum degree: 3 × 10 Pa, gas flow rate: 1.5 SLM, discharge power: 12 kW, gas type: oxygen. The plasma-treated polyimide film A1 was obtained.
Plasma-treated polyimide film A1 instead of polyimide film A1, functional group-free fluororesin film E (Fluon PFA, manufactured by Asahi Glass Co.), F (neoflon PFA, manufactured by Daikin Industries, Ltd.) instead of functional group-containing fluororesin film D2 , G (neoflon FEP, manufactured by Daikin Industries, Ltd.), H (EPE, manufactured by Daikin Industries, Ltd.) and a laminate were prepared and evaluated in the same manner as in Example 1. The evaluation results are shown in Table 6.

[Comparative Examples 1 and 2]
A laminate was prepared and evaluated in the same manner as in Example 1 except that polyimide films B and C were used instead of polyimide film A1. Table 7 shows the evaluation results.
When the linear expansion coefficient of the polyimide film is large, the linear expansion coefficient of the obtained multilayer fluororesin is also large, and the deviation from the linear expansion coefficient of the glass substrate is large, so that the adhesiveness and quality after the reliability test are lowered.

[Comparative Examples 3 and 4]
Example 1 except that functional group-containing fluororesin film I (Fluon LM-ETFE AH2000, manufactured by Asahi Glass Co., Ltd.), J (neoflon EFEP RP5000, manufactured by Daikin Industries, Ltd.) is used instead of functional group-containing fluororesin film D2. A laminate was prepared and evaluated in the same manner. Table 7 shows the evaluation results.
Since ETFE is inferior in heat resistance, moist heat resistance, and electrical properties as compared with perfluorinated resins such as PFA, FEP, and EPE, the adhesiveness and quality after the reliability test are lowered.

[Comparative Examples 5 and 6]
A functional group-free fluororesin film K (Fluon ETFE, manufactured by Asahi Glass Co., Ltd.) and L (neoflon ETFE, manufactured by Daikin Industries) are used in place of the functional group-free fluororesin film E in the same manner as in Example 8. A laminate was prepared by the method and evaluated. The evaluation results are shown in Table 8.
Since ETFE is inferior in heat resistance, moist heat resistance, and electrical properties as compared with perfluorinated resins such as PFA, FEP, and EPE, the adhesiveness and quality after the reliability test are lowered.

[Comparative Examples 7 and 8]
A laminate was prepared and evaluated in the same manner as in Examples 1 and 2 except that the functional group-containing fluororesin film D4 was used instead of the functional group-containing fluororesin film D2. The evaluation results are shown in Table 8.
If the thickness ratio of the fluororesin is too large, the linear expansion coefficient of the resulting multi-layer fluororesin will also increase and the deviation from the linear expansion coefficient of the glass substrate will increase, resulting in decreased adhesion and quality after the reliability test. .

[Comparative Example 9]
A laminate was prepared and evaluated in the same manner as in Comparative Example 7 except that polyimide film A3 was used instead of polyimide film A1. The evaluation results are shown in Table 8.
If the thickness ratio of the fluororesin is too large, the linear expansion coefficient of the resulting multi-layer fluororesin will also increase and the deviation from the linear expansion coefficient of the glass substrate will increase, resulting in decreased adhesion and quality after the reliability test. .

The multilayer fluororesin film in which the (A) fluororesin layer / (B) polyimide resin layer / (A) fluororesin layer of the present invention is laminated in this order has a low linear expansion coefficient (multilayer fluororesin) which is a feature of the polyimide resin. As a film, it is a multilayer film that can achieve both a linear expansion coefficient equivalent to that of an inorganic substrate), high mechanical properties, a low dielectric constant and low water absorption, which are the characteristics of a fluororesin. In addition, since the deviation from the linear expansion coefficient of the inorganic substrate of 2 ppm / ° C. to 6 ppm / ° C. is small and the water absorption rate is low, warpage and distortion hardly occur even in an environment such as high temperature and high humidity. As a result, the quality of the printed circuit and the antenna board obtained as a result, and the production yield are also improved.
The multilayer substrate obtained by laminating the multilayer fluororesin film of the present invention and an inorganic substrate does not cause delamination at high temperatures and high humidity, and is excellent in heat resistance, flame retardancy, dimensional stability, electrical properties, and reliability. It is extremely meaningful in industry.

Claims (5)

  (A) Fluororesin layer / (B) Polyimide resin layer / (A) Fluororesin layer is laminated in this order, and is selected from the group consisting of a ceramic substrate, a glass substrate, and a semiconductor substrate. A multi-layer fluororesin substrate laminated with a substrate, wherein the multi-layer fluororesin substrate is heat-treated at 250 ° C. for 24 hours, and the peel strength between the multi-layer fluororesin film and the substrate is 5 N / cm or more. Multilayer fluororesin substrate. The multilayer fluororesin substrate according to claim 1, wherein the multilayer fluororesin film has a linear expansion coefficient of 0 ppm / ° C to 10 ppm / ° C.   The multilayer fluororesin substrate according to claim 1 or 2, wherein the (A) layer is a layer of a functional group-containing thermoplastic fluororesin.   The multilayer fluororesin substrate according to any one of claims 1 to 3, wherein the layer (B) is a polyimide layer having a polyimide benzoxazole component and has a linear expansion coefficient of -10 ppm / ° C to 10 ppm / ° C.   The multilayer fluororesin substrate according to any one of claims 1 to 3, wherein the (A) layer has a thickness of 1.0 to 20 µm, and the (B) layer has a thickness of 1.0 to 75 µm.