TW202337695A - Metal-clad laminate, circuit board, multilayer circuit board and method of manufacturing the same excellent in dimensional stability of a conductor circuit - Google Patents

Abstract

This invention provides a metal-clad laminate, a circuit board, a multilayer circuit board and a method of manufacturing the same. Provided is a multilayer circuit board which is excellent in dimensional stability of a conductor circuit and has an adhesive layer capable of reducing transmission loss even in transmission of a high-frequency signal. A circuit board (101) includes: an insulating resin layer (10); a conductor circuit layer (50) laminated on one surface of the insulating resin layer (10); and an adhesive layer (30) laminated on the other surface of the insulating resin layer (10). A multilayer circuit board (200) is produced by a method as follows: superimposing an adhesive layer (30) of a first circuit board (101) face to face with a conductor circuit layer (50) of a second circuit board (101), superimposing an adhesive layer (30) of the second circuit board (101) face to face with a conductor circuit layer (50) of any circuit board (110) having no adhesive layer (30), and collectively pressing the same.

Description

Manufacturing method of multilayer circuit substrate

The present invention relates to a metal-clad laminated board and a circuit substrate, a multilayer circuit substrate having a plurality of conductor circuit layers laminated, and a manufacturing method thereof.

In recent years, as electronic devices have become more dense and functional, circuit board materials with further dimensional stability or excellent high-frequency characteristics have been required. In particular, low dielectric constant and low dielectric loss are important for the properties of organic interlayer insulating materials required for high-speed signal processing. In order to cope with the increase in frequency, a multilayer wiring board has been proposed in which a dielectric layer is made of a liquid crystal polymer (LCP) characterized by low dielectric constant and low dielectric loss tangent (for example, Patent Document 1). A multilayer wiring board in which liquid crystal polymer is used as an insulating layer is produced by heating and press-bonding the liquid crystal polymer base material as a thermoplastic resin to a state near the melting point of the thermoplastic resin. Therefore, the liquid crystal polymer base material is easily The thermal deformation of the material will cause the position of the circuit conductor to shift, and there are concerns about impedance (impedance) mismatch, etc., which will adversely affect the electrical characteristics. In addition, multi-layer wiring boards that use liquid crystal polymer as the base material layer do not show an anchoring effect when the multi-layer bonding interface is smooth, and the inter-layer adhesion force is insufficient. Therefore, it is necessary to conduct separate inspections of the circuit conductors and the liquid crystal polymer base material. The surface is roughened, and there is also the problem of complicated manufacturing steps.

As a technology related to an adhesive layer containing polyimide as a main component, it is proposed to apply a cross-linked polyimide resin to an adhesive layer of a coverlay film. Imide resin is obtained by reacting polyimide, which is a diamine compound derived from an aliphatic diamine such as dimer acid, as a raw material, and an amino compound having at least two primary amino groups as functional groups (for example, patent documents 2). The cross-linked polyimide resin of Patent Document 2 has the following advantages: it does not generate volatile components including cyclic siloxane compounds, has excellent solder heat resistance, and does not generate heat even in a use environment where it is repeatedly exposed to high temperatures. This will reduce the adhesion between the wiring layer and the covering film. However, Patent Document 2 does not examine the possibility of application in high-frequency signal transmission. [Prior art documents] [Patent Document]

[Patent Document 1] Japanese Patent Application Laid-Open No. 2005-317953 [Patent Document 2] Japanese Patent Application Publication No. 2013-1730

[Problem to be solved by the invention] In the future, in multilayer circuit boards, as a directionality to cope with high-frequency signal transmission, it is considered to increase the total thickness of the insulating resin layer or adhesive layer while maintaining the dimensional stability of the conductor circuit. Achieve improvements in dielectric properties. For this reason, metal-clad laminates or circuit boards that are used as materials for multilayer circuit boards require different design concepts from those of conventional multilayer circuit boards in terms of not only their materials but also their structures.

Therefore, an object of the present invention is to provide a multilayer circuit board having a novel structure that is excellent in dimensional stability of a conductor circuit and can reduce transmission loss even in the transmission of high-frequency signals. [Technical means to solve problems]

The inventors of the present invention conducted diligent research and found that by using a metal-clad laminate with a specific structure as a material for a multilayer circuit board, it is possible to maintain excellent adhesion while maintaining the dimensional stability of the conductor circuit while also being able to cope with high frequencies. signal transmission, thereby completing the present invention.

That is, the metal-clad laminated board of the present invention includes: an insulating resin layer; a metal layer laminated on one side of the insulating resin layer; and an adhesive layer laminated on the other side of the insulating resin layer. In addition, the circuit board of the present invention includes: an insulating resin layer; a conductor circuit layer formed on one side of the insulating resin layer; and an adhesive layer laminated on the other side of the insulating resin layer. Furthermore, in the metal-clad laminate or circuit board of the present invention, the resin constituting the adhesive layer is a thermoplastic resin or a thermosetting resin, and satisfies the following conditions (i) to (iii): (i) The storage elastic modulus at 50°C is below 1800 MPa; (ii) The maximum value of the storage elastic modulus in the temperature range from 180°C to 260°C is 800 MPa or less; (iii) The glass transition temperature (Tg) is 180°C or less.

In the metal-clad laminate or circuit substrate of the present invention, the thermoplastic resin may be an adhesive polyimide containing a tetracarboxylic acid residue and a diamine residue. In this case, the adhesive polyimide may contain 50 mole parts or more of the diamine residue derived from the dimer acid-type diamine with respect to 100 mole parts of the total amount of the diamine residues. group, the dimer acid-type diamine is formed by substituting the two terminal carboxylic acid groups of the dimer acid with primary aminomethyl or amino groups.

The metal-clad laminated board of the present invention may be a material for a circuit board formed by processing the metal layer into wiring.

In the metal-clad laminate or circuit board of the present invention, the adhesive polyimide may contain a total of 90 mole parts or more of the following based on 100 mole parts of the total amount of the tetracarboxylic acid residues: The tetracarboxylic acid residue derived from the tetracarboxylic anhydride represented by the general formula (1) and/or the general formula (2).

[Chemical 1]

In the general formula (1), A cyclic saturated hydrocarbon group in a 7-membered ring, 7-membered ring or 8-membered ring.

[Chemicalization 2]

In the formula, Z represents -C ₆ H ₄ -, -(CH ₂ )n- or -CH ₂ -CH(-OC(=O)-CH ₃ )-CH ₂ -, and n represents an integer from 1 to 20 .

In the metal-clad laminate or circuit board of the present invention, the adhesive polyimide may be at least 50 mole parts and not more than 99 mole parts relative to 100 mole parts of the total amount of the diamine residues. The diamine residue derived from the dimer acid-type diamine may be contained within the range of 1 molar part or more and 50 molar parts or less selected from the group consisting of the following general formula (B1) to A diamine residue derived from at least one diamine compound among the diamine compounds represented by general formula (B7).

[Chemical 3]

In the formulas (B1) to (B7), R ₁ independently represents a monovalent hydrocarbon group or an alkoxy group having 1 to 6 carbon atoms, and the linking group A independently represents a group selected from -O-, -S-, -CO-, The divalent group in -SO-, -SO ₂ -, -COO-, -CH ₂ -, -C(CH ₃ ) ₂ -, -NH- or -CONH-, n ₁ independently represents an integer from 0 to 4 ; Among them, the part that is repeated with the formula (B2) is removed from the formula (B3), and the part that is repeated with the formula (B4) is removed from the formula (B5).

The multilayer circuit board of the present invention is formed by laminating a plurality of circuit boards, and is characterized by including at least one of the circuit boards as the circuit board.

The manufacturing method of the multilayer circuit substrate according to the first aspect of the present invention may include: The step of preparing a plurality of circuit substrates, the circuit substrates including an insulating resin layer, a conductor circuit layer formed on one side of the insulating resin layer, and an adhesive layer laminated on the other side of the insulating resin layer; and The step of overlapping and crimping the conductor circuit layer of one of the circuit substrates and the adhesive layer of the other circuit substrate in an opposing manner.

The manufacturing method of the multilayer circuit substrate according to the second aspect of the present invention may include: The step of preparing a plurality of circuit substrates, the circuit substrates including an insulating resin layer, a conductor circuit layer formed on one side of the insulating resin layer, and an adhesive layer laminated on the other side of the insulating resin layer; and The step of overlapping and pressing the adhesive layer of one of the circuit substrates and the adhesive layer of the other circuit substrate in a facing manner. [Effects of the invention]

The metal-clad laminated board of the present invention has a structure in which a metal layer is provided on one side of the insulating resin layer and an adhesive layer is provided on the other side of the insulating resin layer. Therefore, a multilayer circuit board can be easily manufactured by laminating. Useful as a material for multilayer circuit boards. In addition, when a multilayer circuit board is manufactured using a metal-clad laminate, the coating and adhesion to the conductor circuit layer can be ensured while maintaining the dimensional stability of the conductor circuit, thereby ensuring the thickness of the entire resin layer. Therefore, by using the metal-clad laminated board of the present invention, a multilayer circuit board having good interlayer connection and high reliability can be obtained. In addition, the multilayer circuit board of the present invention can reduce transmission loss even in the transmission of high-frequency signals, and can realize high-density integration or high-density mounting of electronic components. In addition, since the multilayer circuit board of the present invention is also excellent in heat resistance, it can also mount a semiconductor chip that generates a large amount of heat.

Embodiments of the present invention will be described in detail.

[metal clad laminate] FIG. 1 is a cross-sectional view showing the structure of a metal-clad laminated board according to an embodiment of the present invention. The metal-clad laminate 100 of this embodiment includes: an insulating resin layer 10; a metal layer 20 laminated on one side of the insulating resin layer 10; and an adhesive layer 30 laminated on the other side of the insulating resin layer 10. That is, the metal-clad laminated board 100 has a structure in which the metal layer 20 / the insulating resin layer 10 / the adhesive layer 30 are laminated in this order. If other expressions are used, the metal-clad laminated board 100 has an adhesive layer 30 added to the back side (the insulating resin layer 10 side) of the single-sided metal-clad laminated board 40 in which the insulating resin layer 10 and the metal layer 20 are laminated. structure. Furthermore, the adhesive layer 30 may be formed on the entire surface of one side of the insulating resin layer 10 , or may be formed on only a part thereof.

＜Single-sided metal clad laminate＞ The structure of the single-sided metal-clad laminated board 40 is not particularly limited, and a common material that is a flexible printed circuit (FPC) material can be used. For example, a commercially available copper-clad laminated board can be used. For example, as commercially available copper-clad laminated boards, R-F705T (trade name) manufactured by Panasonic Corporation, Espanex (trade name) manufactured by Nippon Steel Chemical & Materials Co., Ltd., etc. can be used .

(metal layer) The material of the metal layer 20 is not particularly limited, and examples thereof include: copper, stainless steel, iron, nickel, beryllium, aluminum, zinc, indium, silver, gold, tin, zirconium, tantalum, titanium, lead, magnesium, manganese, and the like. Alloys etc. Among these, copper or a copper alloy is particularly preferred. In addition, the material of the wiring layer in the circuit board of this embodiment which will be described later is also the same as that of the metal layer 20 .

The thickness of the metal layer 20 is not particularly limited. For example, when a metal foil such as copper foil is used, it is preferably 35 μm or less, and more preferably within the range of 5 μm to 25 μm. From the viewpoint of production stability and handleability, the lower limit of the thickness of the metal layer is preferably 5 μm. In addition, when copper foil is used, it may be rolled copper foil or electrolytic copper foil. In addition, as the copper foil, a commercially available copper foil can be used.

In addition, the metal foil may be subjected to anti-rust treatment, for example, or surface treatment using, for example, siding, aluminum alcoholate, aluminum chelate, silane coupling agent, etc. for the purpose of improving adhesion.

(Insulating resin layer) The insulating resin layer 10 is not particularly limited as long as it contains an electrically insulating resin. Examples thereof include polyimide, liquid crystal polymer, epoxy resin, phenol resin, polyethylene, polypropylene, and polytetrafluoroethylene. Ethylene, silicone, ethylene tetrafluoroethylene (ETFE), bismaleimide triazine (BT) resin, etc., preferably contain polyimide. In addition, in the present invention, when called polyamide imine, it refers to polyamide imine, polyether imide, polyester imine, and polysiloxane imine in addition to polyamide imine. , polybenzimidazole imine and other polymers with imine groups in their molecular structure.

In addition, the insulating resin layer 10 is not limited to a single layer, and a plurality of resin layers may be laminated. In addition, the insulating resin layer 10 preferably includes a non-thermoplastic polyimide layer formed of non-thermoplastic polyimide. In addition, the so-called "non-thermoplastic polyimide" is usually a polyimide that does not show adhesiveness even if it is softened by heating. In the present invention, it refers to a polyimide that uses a dynamic viscoelasticity measuring device (dynamic mechanical analyzer). (Dynamic Mechanical Analyzer, DMA)), the storage elastic modulus at 30°C is 1.0×10 ⁹ Pa or more and the storage elastic modulus at 300°C is 3.0×10 ⁸ Pa or more.

The insulating resin layer 10 can be selected and used from, for example, a commercially available polyimide film, a commercially available liquid crystal polymer film, or a resin used as an insulating base material in a commercially available metal-clad laminate. As the polyimide film, Upilex (trade name) manufactured by Ube Kosan Co., Ltd., Kapton (trade name) manufactured by Toray Dupont Co., Ltd., Kapton Apical (trade name) manufactured by Kaneka Company and Pixeo (trade name) manufactured by Kaneka Company. As the liquid crystal polymer film, Kuraray can be used Vecstar (trade name) manufactured by Kuraray, BIAC Film (trade name) manufactured by Primatech, etc.

The thermal expansion coefficient (Coefficient of Thermal Expansion, CTE) of the insulating resin layer 10 is not particularly limited, and may be 10 ppm/K or more, preferably 10 ppm/K or more and 30 ppm/K or less, and more preferably 15 ppm. /K and above and below 25 ppm/K. If the CTE is less than 10 ppm/K or exceeds 30 ppm/K, warpage will occur or dimensional stability will decrease. The desired CTE can be controlled by appropriately changing the combination of raw materials used, thickness, and drying/hardening conditions.

Furthermore, the coefficient of thermal expansion (CTE) of the entire resin layer including the insulating resin layer 10 and the adhesive layer 30 is not particularly limited, but is preferably in the range of 10 ppm/K or more and 30 ppm/K or less, and more preferably 15. Within the range of ppm/K and above and 25 ppm/K and below. If the CTE of the entire resin layer is less than 10 ppm/K or exceeds 30 ppm/K, warpage occurs or dimensional stability decreases.

For example, when the insulating resin layer 10 is used in a multilayer circuit board, in order to suppress deterioration of dielectric loss, the dielectric loss tangent (Tan δ) at 10 GHz is preferably 0.02 or less, and more preferably 0.0005 or more and 0.01 or less. within the range, and more preferably within the range of 0.001 or more and 0.008 or less. If the dielectric loss tangent of the insulating resin layer 10 at 10 GHz exceeds 0.02, when applied to a multilayer circuit board, problems such as loss of electrical signals will easily occur on the transmission path of high-frequency signals. On the other hand, the lower limit value of the dielectric loss tangent at 10 GHz of the insulating resin layer 10 is not particularly limited, and can be considered as a physical property control of the insulating resin layer of the multilayer circuit board.

When the insulating resin layer 10 is used as an insulating resin layer of a multilayer circuit board, for example, in order to ensure impedance matching, it is preferable that the dielectric constant (ε) at 10 GHz is 4.0 or less. If the dielectric constant of the insulating resin layer 10 at 10 GHz exceeds 4.0, when applied to a multilayer circuit board, the dielectric loss of the insulating resin layer 10 will deteriorate and electrical signals will easily be generated on the transmission path of high-frequency signals. losses and other adverse situations.

＜Adhesive layer＞ The adhesive layer 30 contains thermoplastic resin or thermosetting resin and meets the following conditions: (i) The storage elastic modulus at 50°C is below 1800 MPa; (ii) The maximum value of the storage elastic modulus from 180°C to 260°C is less than 800 MPa; and (iii) The glass transition temperature (Tg) is 180°C or less. Examples of such resins include polyimide resin, polyamide resin, epoxy resin, phenoxy resin, acrylic resin, polyurethane resin, styrene resin, polyester resin, and phenol resin. Polystyrene resin, polyetherstyrene resin, polyphenylene sulfide resin, polyethylene resin, polypropylene resin, silicone resin, polyetherketone resin, polyvinyl alcohol resin, polyvinyl butyral resin, styrene-male Resins such as imine copolymer, maleimide-vinyl compound copolymer, (meth)acrylic acid copolymer, benzoxazine resin, bismaleimide resin and cyanate ester resin can be purchased from Among these, a resin that satisfies the conditions (i) to (iii) is selected or designed to satisfy the conditions (i) to (iii) and used in the adhesive layer 30 .

When the adhesive layer 30 is a thermosetting resin, it may contain an organic peroxide, a hardener, a hardening accelerator, etc. If necessary, a hardener and a hardening accelerator, or a catalyst and a cocatalyst may be used in combination. The amount and presence of addition of the hardener, hardening accelerator, catalyst, cocatalyst, and organic peroxide may be determined within a range that ensures the conditions (i) to (iii) described above.

As shown in the conditions (i) and (ii), the storage elastic modulus of the adhesive layer 30 at 50°C is 1800 MPa or less, and the maximum value of the storage elastic modulus in the temperature range from 180°C to 260°C is Below 800 MPa. This characteristic of the adhesive layer 30 is considered to be the main reason for alleviating internal stress during thermocompression bonding and maintaining dimensional stability after circuit processing. In addition, the storage elastic modulus of the adhesive layer 30 at the upper limit temperature (260° C.) of the temperature range is preferably 800 MPa or less, and more preferably 500 MPa or less. By setting such a storage elastic modulus, warpage is less likely to occur even after the solder reflow step after circuit processing.

As shown in the condition (iii), the glass transition temperature (Tg) of the adhesive layer 30 may be in the range of 180°C or lower, preferably 160°C or lower. By setting the glass transition temperature of the adhesive layer 30 to 180° C. or lower, thermocompression bonding at low temperature can be performed. Therefore, internal stress generated during lamination can be relaxed and dimensional changes can be suppressed. If the Tg of the adhesive layer 30 exceeds 180° C., the temperature during bonding between the insulating resin layer 10 and any circuit board becomes high, which may impair dimensional stability.

(CTE of adhesive layer) Although the thermoplastic resin or thermosetting resin constituting the adhesive layer 30 has high thermal expansion, it has low elasticity and a low glass transition temperature. Therefore, even if the CTE exceeds 30 ppm/K, it can relax the internal stress generated during lamination. . Therefore, the CTE of the adhesive layer 30 is preferably 35 ppm/K or more, more preferably 35 ppm/K or more and 200 ppm/K or less, further preferably 35 ppm/K or more and 150 ppm/K or less. within. By appropriately changing the combination of raw materials used, thickness, and drying/hardening conditions, the adhesive layer 30 having a desired CTE can be produced.

(Dielectric loss tangent of adhesive layer) For example, when the adhesive layer 30 is used in a multilayer circuit board, in order to suppress deterioration of dielectric loss, the dielectric loss tangent (Tan δ) at 10 GHz is preferably 0.004 or less, more preferably 0.003 or less, and still more preferably 0.002 or less. . If the dielectric loss tangent of the adhesive layer 30 at 10 GHz exceeds 0.004, when applied to a multilayer circuit substrate, problems such as loss of electrical signals will easily occur on the transmission path of high-frequency signals. On the other hand, the lower limit value of the dielectric loss tangent of the adhesive layer 30 at 10 GHz is not particularly limited.

(Dielectric constant of adhesive layer) For example, when the adhesive layer 30 is used in a multilayer circuit board, in order to ensure impedance matching, the dielectric constant at 10 GHz is preferably 4.0 or less. If the dielectric constant of the adhesive layer 30 at 10 GHz exceeds 4.0, when applied to a multilayer circuit substrate, the dielectric loss of the adhesive layer 30 will deteriorate and electrical signals will easily be generated on the transmission path of high-frequency signals. losses and other adverse situations.

(filler) If necessary, the adhesive layer 30 may also contain filler. Examples of fillers include silica, aluminum oxide, magnesium oxide, beryllium oxide, boron nitride, aluminum nitride, silicon nitride, aluminum fluoride, calcium fluoride, and metal salts of organic phosphinic acid. These may be used alone or in combination of two or more.

(Adhesive polyimide) Next, the resin constituting the adhesive layer 30 is an adhesive thermoplastic polyimide containing a tetracarboxylic acid residue and a diamine residue (hereinafter, sometimes referred to as "adhesive polyimide"). Taking the case of "polyamide") as an example, a specific structural example of the adhesive layer 30 will be described. Adhesive polyimide is produced by imidizing a precursor polyamide acid obtained by reacting a specific acid anhydride and a diamine compound. Therefore, by describing the acid anhydride and the diamine compound, Understand specific examples of adhesive polyimide. In addition, in the present invention, the tetracarboxylic acid residue refers to a tetravalent group derived from tetracarboxylic dianhydride, and the diamine residue refers to a divalent group derived from a diamine compound. In addition, the so-called "thermoplastic polyimide" is generally a polyimide whose glass transition temperature (Tg) can be clearly confirmed. In the present invention, it refers to the storage elasticity mold at 30°C measured using DMA. A polyimide with a storage elastic modulus of 1.0×10 ⁸ Pa or more and a storage elastic modulus at 300°C less than 3.0×10 ⁷ Pa.

(tetracarboxylic acid residue) The adhesive polyimide preferably contains a total of 90 mole parts or more of polyamides represented by the following general formula (1) and/or general formula (2) based on 100 mole parts of all tetracarboxylic acid residues. A tetracarboxylic acid residue derived from a tetracarboxylic anhydride (hereinafter, may be described as "tetracarboxylic acid residue (1)" or "tetracarboxylic acid residue (2)"). In the present invention, a total of 90 mole parts or more of the tetracarboxylic acid residue (1) and/or the tetracarboxylic acid residue (2) is contained with respect to 100 mole parts of all the tetracarboxylic acid residues. It is more preferable to impart solvent solubility to the adhesive polyimide and to easily achieve the coexistence of flexibility and heat resistance of the adhesive polyimide. If the total amount of the tetracarboxylic acid residue (1) and/or the tetracarboxylic acid residue (2) is less than 90 mole parts, the solvent solubility of the adhesive polyimide tends to decrease.

[Chemical 4]

In the general formula (1), A cyclic saturated hydrocarbon group in a 7-membered ring, 7-membered ring or 8-membered ring.

[Chemistry 5]

In the formula, Z represents -C ₆ H ₄ -, -(CH ₂ )n- or -CH ₂ -CH(-OC(=O)-CH ₃ )-CH ₂ -, and n represents an integer from 1 to 20 .

Examples of the tetracarboxylic dianhydride used to derive the tetracarboxylic acid residue (1) include: 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA), 3,3', 4,4'-benzophenone tetracarboxylic dianhydride (BTDA), 3,3',4,4'-diphenyl tetracarboxylic dianhydride (DSDA), 4,4'-oxydiphthalate Phthalic anhydride (ODPA), 4,4'-(hexafluoroisopropylidene)diphthalic anhydride (6FDA), 2,2-bis[4-(3,4-dicarboxyphenoxy) Phenyl]propane dianhydride (BPADA), p-phenylene bis(trimellitic acid monoester anhydride) (TAHQ), ethylene glycol bis-trimellitic anhydride (TMEG), etc.

In addition, examples of the tetracarboxylic dianhydride used to derive the tetracarboxylic acid residue (2) include: 1,2,3,4-cyclobutane tetracarboxylic dianhydride, 1,2,3,4- Cyclopentanetetracarboxylic dianhydride, 1,2,4,5-cyclohexanetetracarboxylic dianhydride, 1,2,4,5-cycloheptanetetracarboxylic dianhydride, 1,2,5,6 - Cycloctanetetracarboxylic dianhydride, etc.

The adhesive polyimide may contain a tetracarboxylic acid residue derived from an acid anhydride other than the tetracarboxylic acid anhydride represented by the above-mentioned general formula (1) or general formula (2) within the range that does not impair the effects of the invention.

(diamine residue) The adhesive polyimide is in the range of 50 mole parts or more, for example, 50 mole parts or more and 99 mole parts or less, preferably 80 mole parts or more, based on 100 mole parts of all diamine residues. , for example, the dimer acid-type diamine residue derived from the dimer acid-type diamine is contained in the range of 80 molar parts or more and 99 molar parts or less. By containing the dimer acid-type diamine residue in the above amount, the dielectric properties of the adhesive layer 30 can be improved, and the thermocompression bonding properties can be improved by lowering the glass transition temperature of the adhesive layer 30 and by lowering the glass transition temperature of the adhesive layer 30 . The elastic modulus is changed to relax the internal stress. In addition, by setting the dimer acid-type diamine residue to be 50 mole parts or more, solvent solubility and thermoplasticity can be imparted, thereby reducing the water absorption of the adhesive layer 30, for example, reducing dimensional changes caused by etching. If the dimer acid-type diamine residue is less than 50 mole parts relative to 100 mole parts of all diamine residues, the solvent solubility of the adhesive polyimide decreases.

Here, the so-called dimer acid type diamine means that the two terminal carboxylic acid groups (-COOH) of the dimer acid are substituted with primary aminomethyl (-CH ₂ -NH ₂ ) or amino groups (-NH ₂ ). into diamine. Dimer acid is a known dibasic acid obtained through intermolecular polymerization of unsaturated fatty acids. Its industrial manufacturing process has been roughly standardized in the industry, and unsaturated fatty acids with carbon numbers of 11 to 22 can be produced using clay catalysts, etc. Obtained by dimerization of fatty acids. The dimer acid obtained industrially contains a dibasic acid with a carbon number of 36 obtained by dimerizing an unsaturated fatty acid with a carbon number of 18 such as oleic acid or linoleic acid as the main component, and may contain any amount depending on the degree of purification. Amount of monomeric acid (carbon number 18), trimer acid (carbon number 54), and other polymeric fatty acids with carbon number 20 to 54. In the present invention, the dimer acid is preferably a compound in which the dimer acid content is increased to 90% by weight or more by molecular distillation. In addition, a double bond remains after the dimerization reaction, but in the present invention, the dimer acid also includes a compound that further undergoes a hydrogenation reaction to reduce the degree of unsaturation.

As a characteristic of the dimer acid-type diamine, the polyimide can be provided with characteristics derived from the skeleton of the dimer acid. That is, the dimer acid-type diamine is an aliphatic giant molecule with a molecular weight of about 560 to 620. Therefore, the molar volume of the molecule can be increased and the polar groups of the polyimide can be relatively reduced. It is considered that the characteristics of this dimer acid-type diamine help suppress the decrease in heat resistance of polyimide and reduce the dielectric constant and dielectric loss tangent to improve the dielectric properties. In addition, it contains two freely moving hydrophobic chains with 7 to 9 carbon atoms and two chain-shaped aliphatic amino groups with a length close to 18 carbon atoms. Therefore, it not only imparts flexibility to the polyimide, but also can be used as a polyimide. Since polyimide has an asymmetric chemical structure or a non-planar chemical structure, it is considered that the polyimide can achieve low dielectric constant and low dielectric loss tangent.

Dimer acid-type diamines are commercially available, for example, PRIAMINE 1073 (trade name) manufactured by CRODA Japan, PRIAMINE 1073 (trade name) manufactured by CRODA Japan, etc. PRIAMINE 1074 (trade name), PRIAMINE 1075 (trade name) manufactured by CRODA Japan, Versamine 551 manufactured by BASF Japan (trade name), Versamine 552 (trade name) manufactured by BASF Japan, etc.

In addition, the adhesive polyimide preferably contains a polyamide selected from the group consisting of the following general formula (B1 ) to the diamine compound represented by general formula (B7), it is more preferable that the diamine residue derived from at least one diamine compound is contained in the range of 1 mole part or more and 20 mole part or less. The diamine compounds represented by the general formulas (B1) to (B7) include a molecular structure having flexibility. Therefore, by using at least one diamine compound selected from these in an amount within the above range, the polymerization rate can be improved. The flexibility of the imine molecular chain imparts solvent solubility and thermoplasticity. In addition, by using the diamine compound represented by the general formula (B1) to the general formula (B7), even when a via hole (through hole) is formed in the adhesive layer 30 by laser processing, for example , by increasing the proportion of aromatic rings in the polyimide molecular structure, the absorbency in the ultraviolet region, for example, can be improved. In addition, the glass transition temperature of the adhesive layer 30 can also be increased, thereby improving the resistance to It is heat resistant to the temperature rise of the base metal caused by laser light incident, so the laser processability can be further improved. If the total amount of diamine residues derived from at least one diamine compound selected from the diamine compounds represented by the following general formula (B1) to general formula (B7) is based on 100 moles of all diamine residues If the amount exceeds 50 molar parts, the flexibility of the adhesive polyimide will be insufficient, and the glass transition temperature will rise. Therefore, the residual stress due to thermocompression bonding will increase and the dimensional change rate after etching will tend to deteriorate.

[Chemical 6]

In the formulas (B1) to (B7), R ₁ independently represents a monovalent hydrocarbon group or an alkoxy group having 1 to 6 carbon atoms, and the linking group A independently represents a group selected from -O-, -S-, -CO-, The divalent group in -SO-, -SO ₂ -, -COO-, -CH ₂ -, -C(CH ₃ ) ₂ -, -NH- or -CONH-, n ₁ independently represents an integer from 0 to 4 . Among them, the part that overlaps the formula (B2) is removed from the formula (B3), and the part that overlaps the formula (B4) is removed from the formula (B5). Furthermore, "independently" means that in one, or in two or more of the formulas (B1) to (B7), a plurality of linking groups A, a plurality of R ₁ or a plurality of n ₁ can be Same or different. In addition, in the formulas (B1) to (B7), the hydrogen atoms in the two terminal amino groups may be substituted, for example, they may be -NR ₂ R ₃ (here, R ₂ and R ₃ independently refer to an alkyl group, etc. optional substituents).

The diamine represented by formula (B1) (hereinafter, may be described as "diamine (B1)") is an aromatic diamine having two benzene rings. It is believed that the diamine (B1) is located in the meta position through the amino group directly bonded to at least one benzene ring and the divalent linking group A, and the polyimide molecular chain has an increased degree of freedom and high flexibility, This helps to improve the flexibility of the polyimide molecular chain. Therefore, by using diamine (B1), the thermoplasticity of polyimide is improved. Here, the coupling group A is preferably -O-, -CH ₂ -, -C(CH ₃ ) ₂ -, -CO-, -SO ₂ -, -S-, -COO-.

Examples of the diamine (B1) include: 3,3'-diaminodiphenylmethane, 3,3'-diaminodiphenylpropane, 3,3'-diaminodiphenyl sulfide, 3, 3'-diaminodiphenyl terine, 3,3-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 3,4'-diaminodiphenylmethane, 3,4'- Diaminodiphenylpropane, 3,4'-diaminodiphenyl sulfide, 3,3'-diaminobenzophenone, (3,3'-diamino)diphenylamine, etc.

The diamine represented by formula (B2) (hereinafter, may be described as "diamine (B2)") is an aromatic diamine having three benzene rings. It is believed that the diamine (B2) is located in the meta position through the amino group directly bonded to at least one benzene ring and the divalent linking group A, and the polyimide molecular chain has an increased degree of freedom and high flexibility, This helps to improve the flexibility of the polyimide molecular chain. Therefore, by using diamine (B2), the thermoplasticity of polyimide is improved. Here, the coupling group A is preferably -O-.

Examples of the diamine (B2) include: 1,4-bis(3-aminophenoxy)benzene, 3-[4-(4-aminophenoxy)phenoxy]aniline, 3-[3- (4-Aminophenoxy)phenoxy]aniline, etc.

The diamine represented by formula (B3) (hereinafter, may be described as "diamine (B3)") is an aromatic diamine having three benzene rings. It is believed that the diamine (B3) is located in the meta position with each other through two divalent linking groups A directly bonded to a benzene ring, and the polyimide molecular chain has an increased degree of freedom and high flexibility, This helps to improve the flexibility of the polyimide molecular chain. Therefore, by using diamine (B3), the thermoplasticity of polyimide is improved. Here, the coupling group A is preferably -O-.

Examples of the diamine (B3) include: 1,3-bis(4-aminophenoxy)benzene (TPE-R), 1,3-bis(3-aminophenoxy)benzene (APB), 4 ,4'-[2-methyl-(1,3-phenylene)dioxy]dianiline, 4,4'-[4-methyl-(1,3-phenylene)dioxy] Dianiline, 4,4'-[5-methyl-(1,3-phenylene)dioxy]dianiline, etc.

The diamine represented by formula (B4) (hereinafter, may be described as "diamine (B4)") is an aromatic diamine having four benzene rings. It is believed that the diamine (B4) has high flexibility because the amino group directly bonded to at least one benzene ring is located in the meta position with the divalent linking group A, thereby contributing to the flexibility of the polyimide molecular chain. improve. Therefore, by using diamine (B4), the thermoplasticity of polyimide is improved. Here, the coupling group A is preferably -O-, -CH ₂ -, -C(CH ₃ ) ₂ -, -SO ₂ -, -CO-, -CONH-.

Examples of the diamine (B4) include bis[4-(3-aminophenoxy)phenyl]methane, bis[4-(3-aminophenoxy)phenyl]propane, bis[4-(3 -Aminophenoxy)phenyl] ether, bis[4-(3-aminophenoxy)phenyl]terine, bis[4-(3-aminophenoxy)]benzophenone, bis[4, 4'-(3-Aminophenoxy)]benzylaniline, etc.

The diamine represented by formula (B5) (hereinafter, may be described as "diamine (B5)") is an aromatic diamine having four benzene rings. It is believed that the diamine (B5) is located in the meta position with each other through two divalent linking groups A directly bonded to at least one benzene ring, and the polyimide molecular chain has an increased degree of freedom and high flexibility. , thereby helping to improve the flexibility of the polyimide molecular chain. Therefore, by using diamine (B5), the thermoplasticity of polyimide is improved. Here, the coupling group A is preferably -O-.

Examples of the diamine (B5) include 4-[3-[4-(4-aminophenoxy)phenoxy]phenoxy]aniline, 4,4'-[oxybis(3,1-ylidene) phenyloxy)]bisaniline, etc.

The diamine represented by formula (B6) (hereinafter, may be described as "diamine (B6)") is an aromatic diamine having four benzene rings. It is thought that the diamine (B6) has high flexibility by having at least two ether bonds, thereby contributing to the improvement of the flexibility of the polyimide molecular chain. Therefore, by using diamine (B6), the thermoplasticity of polyimide is improved. Here, the coupling group A is preferably -C(CH ₃ ) ₂ -, -O-, -SO ₂ -, -CO-.

Examples of the diamine (B6) include 2,2-bis[4-(4-aminophenoxy)phenyl]propane (BAPP), bis[4-(4-aminophenoxy)phenyl] Ether (BAPE), bis[4-(4-aminophenoxy)phenyl]phenone (BAPS), bis[4-(4-aminophenoxy)phenyl]ketone (BAPK), etc.

The diamine represented by formula (B7) (hereinafter, may be described as "diamine (B7)") is an aromatic diamine having four benzene rings. The diamine (B7) is considered to have highly flexible divalent linking groups A on both sides of the diphenyl skeleton, thereby contributing to the improvement of the flexibility of the polyimide molecular chain. Therefore, by using diamine (B7), the thermoplasticity of polyimide is improved. Here, the coupling group A is preferably -O-.

Examples of the diamine (B7) include bis[4-(3-aminophenoxy)]biphenyl, bis[4-(4-aminophenoxy)]biphenyl, and the like.

The adhesive polyimide may contain a diamine residue derived from a diamine compound other than the dimer acid-type diamine and diamine (B1) to diamine (B7) as long as the effect of the invention is not impaired.

In addition, regarding the adhesive polyimide, the molar value of the adhesive polyimide can be determined by selecting the types of the tetracarboxylic acid residues and diamine residues, or when containing two or more tetracarboxylic acid residues or diamine residues. ratio, the thermal expansion coefficient, tensile elastic modulus, glass transition temperature, etc. can be controlled. In addition, when having a plurality of structural units of polyimide, they may exist in the form of blocks or may exist randomly. Preferably, they may exist randomly.

The amide group concentration of the adhesive polyimide is preferably 20% by weight or less. Here, the "imide group concentration" refers to a value obtained by dividing the molecular weight of the amide imine group (-(CO) ₂ -N-) in the polyimide by the molecular weight of the entire structure of the polyimide. . If the acyl imine group concentration exceeds 20% by weight, the molecular weight of the resin itself becomes smaller, the low hygroscopicity deteriorates due to the increase in polar groups, and the elastic modulus increases.

The weight average molecular weight of the adhesive polyimide is, for example, preferably in the range of 10,000 to 400,000, and more preferably in the range of 20,000 to 350,000. If the weight average molecular weight is less than 10,000, the strength of the adhesive layer 30 decreases and the adhesive layer 30 tends to become brittle. On the other hand, if the weight average molecular weight exceeds 400,000, the viscosity increases excessively, and defects such as thickness unevenness and streaks of the adhesive layer 30 tend to easily occur during coating operations.

When forming a multilayer circuit board, the adhesive polyimide covers the conductor circuit layer of any circuit board. Therefore, in order to suppress the diffusion of copper, a completely imidized structure is most preferred. Among them, a part of the polyamide imide may be amide acid. Regarding the acyl imidization rate, it can be determined by using a Fourier transform infrared spectrophotometer (commercially available product: FT/IR620 manufactured by JASCO Corporation) and utilizing the primary reflection ATR (Attenuated Total Reflectance) method. The infrared absorption spectrum of the polyimide film was measured and calculated based on the absorbance of 1780 cm ^-1 derived from C=O stretching of the amide imide group based on the benzene ring absorber near 1015 cm ^-1 .

(Cross-linking formation) When the adhesive polyimide has a ketone group, crosslinking can be formed by reacting the ketone group with the amino group of an amino compound having at least two primary amino groups as functional groups to form a C=N bond. structure. By forming a cross-linked structure, the heat resistance of adhesive polyimide can be improved. Examples of preferred tetracarboxylic anhydrides for forming a polyimide having a ketone group include 3,3',4,4'-benzophenone tetracarboxylic dianhydride (BTDA). Examples of preferred diamine compounds include 4,4'-bis(3-aminophenoxy)benzophenone (BABP), 1,3-bis[4-(3-aminophenoxy)benzoyl]benzene (BABB) and other aromatic Diamine.

Examples of amino compounds that can be used for cross-linking formation of adhesive polyimide include dihydrazide compounds, aromatic diamines, aliphatic amines, and the like. Among these, dihydrazide compounds are preferred. Aliphatic amines other than dihydrazide compounds tend to form a cross-linked structure even at room temperature, which raises concerns about the storage stability of the varnish. On the other hand, aromatic diamines require a high temperature in order to form a cross-linked structure. When a dihydrazide compound is used, the storage stability of the varnish and the shortening of the curing time can be achieved at the same time. Preferred examples of the dihydrazide compound include oxalic acid dihydrazide, malonic acid dihydrazide, succinic acid dihydrazide, glutaric acid dihydrazide, adipic acid dihydrazide, and pimelic acid dihydrazide. Suberic acid dihydrazide, azelaic acid dihydrazide, sebacic acid dihydrazide, dodecanedioic acid dihydrazide, maleic acid dihydrazide, fumaric acid dihydrazide, diglycolic acid dihydrazide Hydrazine, dihydrazide tartrate, dihydrazide malate, dihydrazide phthalate, dihydrazide isophthalate, dihydrazide terephthalate, 2,6-naphthoic acid dihydrazide, 4,4 - Dihydrazide compounds such as diphenyl dihydrazide, 1,4-naphthoic acid dihydrazide, 2,6-pyridinedioic acid dihydrazide, and itaconic acid dihydrazide. The above dihydrazide compounds may be used alone, or two or more types may be mixed and used.

The adhesive polyamide can be produced by reacting the tetracarboxylic dianhydride and the diamine compound in a solvent to generate polyamide, and then heating and closing the reaction. For example, a tetracarboxylic dianhydride and a diamine compound are dissolved in an organic solvent at approximately equimolar amounts, and the polymerization reaction is performed by stirring at a temperature in the range of 0° C. to 100° C. for 30 minutes to 24 hours. Polyamide acid as a precursor to adhesive polyimide. During the reaction, the reaction components are dissolved in the organic solvent so that the resulting precursor is in the range of 5% to 50% by weight, preferably in the range of 10% to 40% by weight. Examples of the organic solvent used in the polymerization reaction include N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAc), and N,N-diethylacetamide. Amine, N-methyl-2-pyrrolidone (NMP), 2-butanone, dimethylsulfoxide (DMSO), hexamethylphosphonamide, N-methylcaprolactam, dimethyl sulfate, cyclohexane Hexanone, dioxane, tetrahydrofuran, diglyme, triglyme, cresol, etc. Two or more of these solvents may be used in combination, and aromatic hydrocarbons such as xylene and toluene may be used in combination. In addition, the usage amount of such an organic solvent is not particularly limited, but it is preferably used in an amount adjusted so that the concentration of the polyamide solution obtained by the polymerization reaction is about 5% by weight to 50% by weight.

The synthesized polyamide is usually advantageously used as a reaction solvent solution, and can be concentrated, diluted or replaced with other organic solvents as necessary. In addition, polyamide is generally used advantageously because it has excellent solvent solubility. The viscosity of the polyamide solution is preferably in the range of 500 cps to 100,000 cps. If it deviates from the above range, defects such as uneven thickness and streaks may easily occur in the film during coating operations using a coater or the like.

The method of imidizing polyamide acid to form polyimide is not particularly limited. For example, it can be suitably carried out in the solvent at a temperature in the range of 80°C to 400°C for 1 hour to 24 hours. Heating and other heat treatments.

When the adhesive polyimide obtained as above is cross-linked, the amino compound is added to a resin solution containing a polyimide having a ketone group, and the adhesive polyimide is The ketone group in the amino compound undergoes a condensation reaction with the primary amino group of the amino compound. The resin solution is hardened by the condensation reaction to become a hardened product. In this case, the amount of the amino compound added may be 0.004 mol to 1.5 mol in total of the primary amino group per 1 mol of ketone group, preferably 0.005 mol to 1.2 mol, and more preferably 0.03 mol. The amino compound is added in an amount of ~0.9 moles, most preferably 0.04 moles to 0.5 moles. Regarding the addition amount of amino compounds such as those where the total amount of the primary amino group is less than 0.004 mol per mole of the ketone group, the cross-linking of the polyimide chain by the amino compound is insufficient, so there is an adhesive layer after hardening. 30 tends to be difficult to develop heat resistance. If the added amount of the amino compound exceeds 1.5 mol, the unreacted amino compound acts as a thermoplastic, and the heat resistance of the adhesive layer 30 tends to decrease.

The conditions for the condensation reaction to form cross-links are not particularly limited as long as the ketone group in the adhesive polyimide reacts with the primary amino group of the amino compound to form an imine bond (C=N bond). limit. The temperature of the heating condensation is for reasons such as releasing the water generated by the condensation out of the system or simplifying the condensation step when the synthesis of the adhesive polyimide is followed by a heating condensation reaction. , for example, preferably in the range of 120°C to 220°C, more preferably in the range of 140°C to 200°C. The reaction time is preferably about 30 minutes to 24 hours. The end point of the reaction can be measured by measuring the infrared absorption spectrum using a Fourier transform infrared spectrophotometer (commercial product: FT/IR620 manufactured by JASCO Corporation) and using 1670 cm ^-1 It was confirmed that the nearby absorption peak derived from the ketone group in the polyimide resin decreased or disappeared, and the nearby absorption peak derived from the imine group appeared near 1635 cm ^-1 .

Thermal condensation of the ketone group of the adhesive polyimide and the primary amino group of the amino compound can be performed, for example, by the following method: (a) Adding the amino group immediately after the synthesis (imidization) of the adhesive polyimide A method of heating the compound; (b) adding an excess amount of amino compound as the diamine component in advance, followed by the synthesis of the adhesive polyimide (imidization), without participating in the imidization or imidization A method of heating the aminated residual amino compound and the adhesive polyimide together; or (c) processing the adhesive polyimide composition to which the amino compound is added into a prescribed shape (for example, A method of heating after coating or forming a film on any base material.

In order to provide heat resistance to the adhesive layer 30, the formation of an imine bond is described in the formation of a cross-linked structure in the adhesive polyimide, but it is not limited to this. As a method of hardening the adhesive layer 30 , for example, epoxy resin, epoxy resin hardener, etc. can also be mixed and hardened.

<Thickness of resin layer> Regarding the metal-clad laminated board 100, when the total thickness of the thickness T3 of the insulating resin layer 10 and the thickness T2 of the adhesive layer 30 is T1, the total thickness T1 is in the range of 50 μm to 250 μm, preferably 70 Within the range of μm～150 μm. If the total thickness T1 is less than 50 μm, the effect of reducing transmission loss when manufacturing a multilayer circuit board using the metal-clad laminate 100 is insufficient. If the total thickness T1 exceeds 250 μm, there is a concern that productivity decreases.

In addition, the thickness T2 of the adhesive layer 30 is preferably in the range of 20 μm to 200 μm, for example, and more preferably in the range of 20 μm to 100 μm. If the thickness T2 of the adhesive layer 30 is less than the lower limit, the transmission loss of the high-frequency substrate may increase. On the other hand, if the thickness T2 of the adhesive layer 30 exceeds the upper limit, problems such as reduced dimensional stability may occur.

In addition, the ratio (T2/T1) of the thickness T2 of the adhesive layer 30 to the total thickness T1 is in the range of 0.5 to 0.8, preferably in the range of 0.5 to 0.7. If the ratio (T2/T1) is less than 0.5, it will be difficult to set the total thickness T1 to 50 μm or more. If it exceeds 0.8, problems such as reduced dimensional stability will occur.

The thickness T3 of the insulating resin layer 10 is, for example, preferably in the range of 12 μm to 100 μm, and more preferably in the range of 12 μm to 50 μm. If the thickness T3 of the insulating resin layer 10 is less than the lower limit, problems such as warpage of the metal-clad laminate 100 may occur. If the thickness T3 of the insulating resin layer 10 exceeds the upper limit, problems such as reduced productivity may occur.

In the metal-clad laminate 100 of this embodiment, the thickness T2 of the adhesive layer 30 itself is increased in order to realize low dielectric loss tangent of the entire resin layer and to cope with high-frequency transmission. However, in general, materials with a low elastic modulus exhibit a high thermal expansion coefficient, so there is a concern that increasing the layer thickness will lead to a decrease in dimensional stability. Here, it is considered that the dimensional changes that occur when the metal-clad laminated board 100 is subjected to circuit processing and multi-layered circuits are formed mainly due to the following mechanisms a) to c), and the total amount of b) and c) becomes the post-etching Appears due to size changes. a) When manufacturing the metal-clad laminated board 100, internal stress is accumulated in the resin layer. b) During circuit processing, the internal stress accumulated in a) is released by etching the metal layer 20, and the resin layer expands or contracts. c) During circuit processing, by etching the metal layer 20, the exposed resin absorbs moisture and expands.

The main causes of the internal stress in a) are: 1) the difference in thermal expansion coefficient between the metal layer 20 and the resin layer; 2) the internal strain of the resin generated by film formation. Here, the magnitude of the internal stress caused by 1) is affected not only by the difference in thermal expansion coefficient, but also by the temperature difference ΔT between the bonding temperature (heating temperature) during multilayer circuit formation and the cooling and solidification temperature. That is, the internal stress increases in proportion to the temperature difference ΔT. Therefore, even if the difference in thermal expansion coefficient between the metal layer 20 and the resin layer is small, the internal stress increases as high-temperature resin is required for bonding. In the metal-clad laminated board 100 of this embodiment, by using the adhesive layer 30 that satisfies the above conditions (i) to (iii), internal stress is reduced and dimensional stability is ensured. In addition, since the adhesive layer 30 is laminated on the insulating resin layer 10, when forming a multilayer circuit board, it functions as an intermediate layer and suppresses warpage and dimensional changes.

[Metal-clad laminate manufacturing method] The metal-clad laminated board 100 can be manufactured by the following method 1 or method 2, for example. [method 1] The resin composition to be the adhesive layer 30 is formed into a film shape to prepare an adhesive film. The adhesive film is arranged and bonded so as to face the insulating resin layer 10 of the single-sided metal-clad laminate 40 , and then Thermocompression bonding method. [Method 2] A method of applying a solution of the resin composition that becomes the adhesive layer 30 to a predetermined thickness on the insulating resin layer 10 of the single-sided metal-clad laminate 40 and drying the solution. In this case, if necessary, heating or other treatment for performing a hardening reaction or a cross-linking reaction may be performed.

The adhesive film used in Method 1 can be produced, for example, by applying a solution of the resin composition to be the adhesive layer 30 to any supporting base material, drying the solution, and then peeling the solution from the supporting base material. As the adhesive film, an adhesive polyimide film obtained by forming the adhesive polyimide into a film shape can also be used. Examples of methods for producing an adhesive polyimide film include the following method: [1] Apply a polyimide solution to a support base material, dry it, perform heat treatment to imidize it, and then self-coat the polyimide film. A method of peeling off a support base material to produce an adhesive film; [2] Coating a polyamide solution on the support base material and drying it, and then peeling off the polyamide gel film from the support base material and subjecting it to heat treatment. A method of producing an adhesive film by imidization; [3] A method of coating a support base material with an adhesive polyimide solution and drying it, and then peeling off the self-supporting base material to produce an adhesive film. Among the above [1] to [3], the preferred method is [3] in which a solution of an adhesive polyimide that has been imidized in a polyamide acid solution is applied onto a supporting base material and dried. method to form. Since the adhesive polyimide is solvent-soluble, it is advantageous to imidize the polyamide acid in a solution state and to use it directly as a coating liquid for the adhesive polyimide. Furthermore, the adhesive polyimide constituting the adhesive film can also be formed by cross-linking using the above method.

In the above methods 1 and 2, the method for applying the solution of the resin composition that becomes the adhesive layer 30 on the supporting base material or the insulating resin layer 10 is not particularly limited. For example, a notch wheel or a mold can be used. , scraper, die lip and other coating machines for coating. In the step of forming the adhesive layer 30, it is preferable that the surface of the formed adhesive layer 30 be formed into a flat shape. In addition, it is preferable that the thickness of the adhesive layer 30 is also formed uniformly. By forming the surface of the adhesive layer 30 into a flat shape and making the thickness uniform, the adhesiveness in the manufacturing step of the multilayer circuit substrate is improved.

The metal-clad laminated board 100 of the present embodiment obtained as above can be manufactured by performing wiring circuit processing on the metal layer 20 to produce a single-sided FPC or a double-sided FPC. In addition, the adhesiveness of the adhesive layer 30 is utilized, or the By stacking a plurality of single-sided FPCs or double-sided FPCs using arbitrary bonding sheets, a multilayer circuit board can be manufactured.

[Circuit board] 2 is a cross-sectional view showing the structure of a circuit board according to an embodiment of the present invention. The circuit substrate 101 includes: an insulating resin layer 10; a conductor circuit layer 50 laminated on one side of the insulating resin layer 10; and an adhesive layer 30 laminated on the other side of the insulating resin layer 10. That is, the circuit board 101 has a structure in which the conductor circuit layer 50 / the insulating resin layer 10 / the adhesive layer 30 are laminated in this order. The circuit board 101 of this embodiment is obtained by subjecting the metal layer 20 of the metal-clad laminate 100 to wiring circuit processing.

(conductor circuit layer) The conductive circuit layer 50 is a layer in which a conductive circuit is formed in a predetermined pattern on one side of the insulating resin layer 10 . For example, a photosensitive resist is coated on the metal layer 20 of the metal-clad laminate 100, exposed and developed to form a predetermined mask pattern, and the metal layer 20 is etched through the mask pattern, and then the mask pattern is removed. , thereby forming the conductor circuit layer 50 of a predetermined pattern. Note that the “conductor circuit layer” refers to an in-plane connection electrode (land electrode) formed in the surface direction of the insulating resin layer 10, and an interlayer connection electrode (via electrode). difference.

Regarding the conductor circuit layer 50 , from the viewpoint of reducing transmission loss in high-frequency transmission, the maximum height roughness (Rz) of the surface in contact with the insulating resin layer 10 is preferably 1.0 μm or less. Transmission loss includes the sum of conductor loss and dielectric loss. If Rz of the conductor circuit layer 50 is large, the conductor loss becomes large and adversely affects the transmission loss. Therefore, it is preferable to control Rz.

The structures of the insulating resin layer 10 and the adhesive layer 30 in the circuit board 101 of this embodiment are as described for the metal-clad laminate 100 .

[Multilayer circuit board] Next, the multilayer circuit board according to the embodiment of the present invention will be described with reference to FIGS. 3 to 6 . Generally, the multilayer circuit board has a laminate including a plurality of insulating resin layers and two or more conductor circuit layers embedded in the laminate, and preferably has at least two or more insulating resin layers and at least two layer above the conductor circuit layer. Here, two preferred embodiments of the multilayer circuit board will be described. The multilayer circuit board 200 and the multilayer circuit board 201 of this embodiment include at least one of the circuit boards 101 described above. In addition, the multilayer circuit board 200 and the multilayer circuit board 201 of this embodiment may include one or more arbitrary circuit boards other than the circuit board 101 that are laminated on the circuit board 101 .

<First Embodiment> FIG. 3 is a cross-sectional view in the lamination direction showing the structure of the multilayer circuit board 200 according to the first embodiment of the present invention. The multilayer circuit board 200 of the first embodiment has a structure in which a plurality of circuit boards 101 and an arbitrary circuit board 110 are stacked and laminated in the same direction. That is, from the upper side to the lower side in FIG. 3 , the adhesive layer 30 of the first circuit board 101 is connected and laminated so as to cover the conductor circuit layer 50 of the second circuit board 101 , and further, the second circuit board 101 The adhesive layer 30 is connected and laminated so as to cover the conductor circuit layer 50 of any circuit board 110 that does not have the adhesive layer 30 . Here, the structure or material of any circuit substrate 110 is not limited. For example, the conductor circuit layer 50 may be formed of a patterned metal layer 20 or may have a damascene structure. In addition, the conductor circuit layer 50 of any circuit board 110 can be formed on the insulating resin layer 10 by inkjet, sputtering, plating, or the like. Furthermore, the thickness, material, physical properties, etc. of the conductor circuit layer 50 or the insulating resin layer 10 of the arbitrary circuit board 110 are not particularly limited.

In FIG. 3 , a laminated structure of two circuit boards 101 and one arbitrary circuit board 110 is shown, but three or more circuit boards 101 may be laminated. In addition, the adhesive layer 30 may cover the entire conductor circuit layer 50 of the adjacent circuit board 101 or any circuit board 110, or may cover a part thereof. Furthermore, in the multilayer circuit board 200, the conductive circuit layer 50 is exposed on the surface of the uppermost circuit board 101, and any protective film covering the uppermost conductive circuit layer 50 may be provided. 3 illustrates an arbitrary circuit board 110 in which the conductor circuit layer 50 is formed on one side of the insulating resin layer 10 . The conductor circuit layer 50 may be formed on both sides of the insulating resin layer 10 .

FIG. 4 is a manufacturing step diagram of the multilayer circuit board 200 according to the first embodiment. First, a plurality of circuit boards 101 and an arbitrary circuit board 110 are prepared. Furthermore, the adhesive layer 30 of the first circuit board 101 is overlapped and disposed so as to face the conductor circuit layer 50 of the second circuit board 101, and the adhesive layer 30 of the second circuit board 101 is arranged so as to have no The adhesive layer 30 can be manufactured by arranging the conductor circuit layers 50 of any of the circuit boards 110 to face each other and pressing them together (pressing step). In addition, FIG. 4 shows an example in which two circuit boards 101 are laminated. However, three or more circuit boards 101 may be laminated at one time. In addition, the arbitrary circuit board 110 is not limited to one, and a plurality of circuit boards 110 may be stacked.

Since the surface of the adhesive layer 30 of the circuit substrate 101 is flattened, no gaps or the like will be generated in the adhesive layer 30 during the crimping step, and the adhesive resin can be filled between the conductor circuits of the conductor circuit layer 50. Stacking is performed in the state. In addition, if necessary, the thickness adjustment step of adjusting the thickness of the adhesive layer 30 may be performed by pressing the laminated multilayer circuit board 200 from both sides using a pressure roller or a pressing device. Through the thickness adjustment step, the overall thickness accuracy of the adhesive layer 30 and the multilayer circuit substrate 200 can be improved. Furthermore, during pressure bonding, a heat treatment of heating at a temperature of 60° C. to 220° C. may be performed. Thereby, the multilayer circuit board 200 in which a plurality of circuit boards are integrally laminated can be manufactured. During the heat treatment, a cross-linked structure of imine bonds may be formed in the adhesive layer 30 by, for example, heat condensation of adhesive polyimide.

In this embodiment, the adhesive layer 30 of each circuit board 101 functions as an adhesive sheet for bonding the circuit boards to each other, and as a protective film for protecting the conductor circuit. Therefore, there is no need to separately prepare an adhesive sheet or a protective layer for conductor circuits and have them interposed between the circuit substrates, thereby achieving simplification of processes and equipment, simplification of materials, and cost reduction for forming multilayer circuits.

The multilayer circuit board 200 obtained as above includes a structure in which an adhesive layer 30 with sufficient thickness is provided between the conductor circuit layer 50 and the insulating resin layer 10 to ensure insulation, flexibility, and low dielectric properties. Furthermore, in the multilayer circuit board 200 of this embodiment, a layer such as a cover film or a solder resist may be provided as a protective layer if necessary. Although illustration is omitted, chip-type electronic components such as IC chips or chip capacitors, chip coils, and chip resistors may be built into the multilayer circuit board 200 of this embodiment. In addition, in the multilayer circuit board 200 of this embodiment, interlayer connection electrodes (via-hole electrodes) not shown may be formed. The interlayer connection electrode can be formed by forming a via hole in the insulating resin layer 10 by laser processing or drilling, and then filling the conductive paste with printing or the like. For example, a conductive paste obtained by mixing an organic solvent, an epoxy resin, or the like with a conductive powder containing tin as a main component can be used. In addition, the interlayer connection electrode may form a plated portion on a part of the inner surface of the via hole and the surface of the conductive circuit layer 50 after the via hole is formed.

<Second Embodiment> FIG. 5 is a cross-sectional view in the lamination direction showing the structure of the multilayer circuit board 201 according to the second embodiment of the present invention. In the multilayer circuit board 201 of the second embodiment, a structure in which a pair of circuit boards 101 are bonded so that the adhesive layers 30 face each other is used as one circuit board unit 102 and includes at least one or more of them. The circuit substrate unit 102 is described. That is, from the top to the bottom in FIG. 5 , the first metal-clad laminated board 100 , the circuit board unit 102 , and the second metal-clad laminated board 100 are arranged in this order (wherein, the first metal-clad laminated board 100 is opposite to direction), and lamination is performed in the form of sandwiching the circuit substrate unit 102 between the adhesive layers 30 of the two metal-clad laminate boards 100 . The adhesive layer 30 of the first metal-clad laminated board 100 is laminated so as to be in contact with the conductor circuit layer 50 on one side of the circuit board unit 102 (the upper side in the figure), and further, on the other side of the circuit board unit 102 The conductive circuit layer 50 on one side (the lower side in the figure) and the adhesive layer 30 of the second metal-clad laminated board 100 are laminated so as to be in contact with the conductive circuit layer 50 . Furthermore, in FIG. 5 , a laminated structure including only one circuit board unit 102 is shown, but it can also be made to include a plurality of circuit board units 102 by further interposing an adhesive sheet or a circuit board 101 or an arbitrary circuit board 110 . layered structure. In addition, the circuit board 101 may be used as one or both of the upper and lower metal-clad laminates 100 .

FIG. 6 is a manufacturing step diagram of the multilayer circuit board 201 of the second embodiment. First, one circuit substrate unit 102 and two metal-clad laminate boards 100 are prepared. Here, the circuit substrate unit 102 can be produced by preparing a pair of circuit substrates 101 and bonding the adhesive layer 30 of one circuit substrate 101 to the adhesive layer 30 of the other circuit substrate 101 . Furthermore, the multilayer circuit board 201 can be manufactured by arranging the adhesive layer 30 of the first metal-clad laminated board 100 to face the conductor circuit layer 50 on the upper surface side of the circuit board unit 102, and further, on the circuit board The conductor circuit layer 50 on the lower surface side of the unit 102 and the adhesive layer 30 of the second metal-clad laminate 100 are arranged to face the conductor circuit layer 50, and these are crimped together (crimping step).

Furthermore, the circuit substrate unit 102 may not be produced, but the adhesive layer 30 of the first metal-clad laminated board 100 may be arranged to face the conductor circuit layer 50 of the upper circuit substrate 101, and the adhesive layer of the upper circuit substrate 101 may be The connecting layer 30 and the adhesive layer 30 of the lower circuit substrate 101 are arranged to face each other. Furthermore, the conductor circuit layer 50 of the lower circuit substrate 101 and the adhesive layer 30 of the second metal-clad laminate 100 are in contact with each other. The conductor circuit layers 50 are arranged to face each other, and these are crimped together.

If necessary, the thickness adjustment step of adjusting the thickness of the adhesive layer 30 may be performed by pressing the laminated multilayer circuit board 201 from both sides using a pressure roller or a pressing device. Through the thickness adjustment step, the overall thickness accuracy of the adhesive layer 30 and the multilayer circuit substrate 201 can be improved. Furthermore, during pressure bonding, a heat treatment of heating at a temperature of 60° C. to 220° C. may be performed. Thereby, the multilayer circuit board 201 in which a plurality of circuit boards are integrally laminated can be manufactured. During the heat treatment, a cross-linked structure of imine bonds may be formed in the adhesive layer 30 by, for example, heat condensation of adhesive polyimide.

In this embodiment, the adhesive layer 30 of each circuit board 101 also functions as an adhesive sheet for bonding the circuit boards to each other. Therefore, there is no need to separately prepare an adhesive sheet and have it interposed between the circuit substrates, thereby achieving simplification of processes and equipment, simplification of materials, and cost reduction for forming multilayer circuits.

The other structures and effects of the multilayer circuit board 201 of this embodiment are the same as those of the multilayer circuit board 200 of the first embodiment. [Example]

Examples are shown below and the features of the present invention are described in more detail. However, the scope of the present invention is not limited to the Examples. In addition, in the following examples, unless otherwise stated, various measurements and evaluations are based on the following contents.

[Measurement of dimensional change rate] The dimensional change rate was measured in the following order. First, a 150 mm square test piece was used to expose and develop the dry film resist at intervals of 100 mm, thereby forming a target for position measurement. In an environment with a temperature of 23±2°C and a relative humidity of 50±5%, measure the dimensions before etching (normal), and then remove the copper outside the target area of the test piece by etching (liquid temperature 40°C or lower, time within 10 minutes) . After leaving for 24±4 hours in an environment with a temperature of 23±2°C and a relative humidity of 50±5%, measure the etched dimensions. The dimensional change rate from the normal state was calculated for each of three locations in the MD direction (longitudinal direction) and TD direction (width direction), and the average value was used as the dimensional change rate after etching. The dimensional change rate after etching is calculated using the following equation.

Dimensional change rate after etching (%) = (B-A)/A×100 A: Distance between targets before etching B: Distance between targets after etching

Next, this test piece was heated in an oven at 250° C. for 1 hour, and the distance between the positional targets was measured thereafter. The dimensional change rate after etching was calculated for each of three locations in the MD direction (longitudinal direction) and TD direction (width direction), and the average value was used as the dimensional change rate after heat treatment. The heating dimensional change rate is calculated using the following equation.

Dimensional change rate after heating (%) = (C-B)/B×100 B: Distance between targets after etching C: Distance between targets after heating

[Measurement of viscosity] The viscosity at 25°C was measured using an E-type viscometer (manufactured by Brookfield Company, trade name: DV-II+Pro). Set the rotation speed so that the torque is 10% to 90%, and read the value when the viscosity is stable after 2 minutes have passed after starting the measurement.

[Measurement of coefficient of thermal expansion (CTE)] A thermomechanical analyzer (manufactured by Bruker, trade name: 4000SA) was used on a polyimide film of size 3 mm × 20 mm, and a load of 5.0 g was applied while increasing the temperature from 30°C to 30°C at a certain rate. The temperature was raised to 300°C, and the temperature was maintained for 10 minutes, followed by cooling at a rate of 5°C/min, and the average thermal expansion coefficient (thermal expansion coefficient) from 250°C to 100°C was determined.

[Measurement of storage elastic modulus and glass transition temperature (Tg)] A dynamic viscoelasticity measuring device (DMA: manufactured by UBM Co., Ltd., trade name: E4000F) was used for a resin sheet of 5 mm measured under conditions. In addition, the temperature at which the elastic modulus change (tan δ) reaches the maximum is defined as the glass transition temperature.

[Measurement of dielectric constant and dielectric loss tangent] Using a Vector Network Analyzer (manufactured by Agilent, trade name E8363C) and a Split Post Dielectric Resonator (SPDR), the dielectric constant and the dielectric constant of the resin sheet at 10 GHz were measured. Dielectric loss tangent. In addition, the materials used in the measurement are left for 24 hours at a temperature of 24°C to 26°C and a humidity of 45% to 55%RH.

[Measurement of surface roughness of copper foil] An atomic force microscope (AFM) (manufactured by Bruker AXS, trade name: Dimension Icon scanning probe microscope (SPM)) and a probe (Bruker AXS) were used. AXS) company, trade name: TESPA (NCHV), tip radius of curvature 10 nm, spring constant 42 N/m), measure the 80 μm × 80 μm range of the copper foil surface in tapping mode. And find the ten-point average roughness (Rzjis).

The abbreviations used in the synthesis examples represent the following compounds. ○BPDA: 3,3',4,4'-biphenyltetracarboxylic dianhydride ○BPADA: 2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride ○PMDA: Pyromellitic dianhydride ○BTDA: 3,3',4,4'-benzophenone tetracarboxylic dianhydride ○m-TB: 2,2'-dimethyl-4,4'-diaminobiphenyl ○TPE-R: 1,3-bis(4-aminophenoxy)benzene ○Bisaniline-M: 1,3-bis[2-(4-aminophenyl)-2-propyl]benzene ○BAPP: 2,2-bis[4-(4-aminophenoxy)phenyl]propane ○DDA: Aliphatic diamine with 36 carbon atoms (manufactured by CRODA Japan Co., Ltd., trade name: PRIAMINE 1074, amine value: 205 mgKOH/g, cyclic structure and chain structure A mixture of dimer diamines with a structure, the content of the dimer component is: 95% by weight or more) ○DMAc: N,N-dimethylacetamide ○NMP: N-methyl-2-pyrrolidone ○N-12: Dodecanedioic acid dihydrazine ○OP935: Organic phosphinic acid aluminum salt (manufactured by Clariant Japan, trade name: Exolit OP935) ○R710: (trade name, manufactured by Printec Co., Ltd., bisphenol-type epoxy resin, epoxy equivalent 170, liquid at room temperature, weight average molecular weight: about 340) ○VG3101L: (trade name, manufactured by Printec (Co., Ltd.), multifunctional epoxy resin, epoxy equivalent: 210, softening point 39°C to 46°C) ○SR35K: (trade name, manufactured by Printec Co., Ltd., epoxy resin, epoxy equivalent: 930~940, softening point: 86℃~98℃) ○YDCN-700-10: (Trade name, manufactured by Nippon Steel Chemical & Materials Co., Ltd., cresol novolak type epoxy resin, epoxy equivalent 210, softening point 75℃~85℃) ○Milex (milex) mass%) ○HE200C-10: (trade name, manufactured by AIR WATER Co., Ltd., phenolic resin, hydroxyl equivalent: 200, softening point: 65°C to 76°C, water absorption: 1% by mass, heating mass reduction rate: 4 mass%) ○HE910-10: (trade name, manufactured by AIR WATER Co., Ltd., phenolic resin, hydroxyl equivalent: 101, softening point: 83°C, water absorption: 1 mass%, heating mass reduction rate: 3 mass%) ○SC1030-HJA: (trade name, manufactured by Admatechs (Co., Ltd.), silica filler dispersion, average particle size: 0.25 μm) ○Aerosil R972: (trade name, manufactured by Aerosil Japan Co., Ltd., silica, average particle size: 0.016 μm) ○Acrylic rubber (acryl gum) HTR-860P-30B-CHN: (Sample name, manufactured by Teikoku Chemical Industry Co., Ltd., weight average molecular weight: 230,000, glycidyl functional group monomer ratio: 8%, Tg: -7 ℃) ○Acrylic rubber (acryl gum) HTR-860P-3CSP: (Sample name, manufactured by Teikoku Chemical Industry Co., Ltd., weight average molecular weight: 800,000, glycidyl functional group monomer ratio: 3%, Tg: -7°C) ○A-1160: (trade name, manufactured by GE Toshiba Corporation, γ-ureidopropyltriethoxysilane) ○A-189: (trade name, manufactured by GE Toshiba Corporation, γ-mercaptopropyltrimethoxysilane) ○Curezol 2PZ-CN: (trade name, manufactured by Shikoku Chemical Industry Co., Ltd., 1-cyanoethyl-2-phenylimidazole) ○RE-810NM: (trade name, manufactured by Nippon Kayaku Co., Ltd., diallyl bisphenol A diglycidyl ether (properties: liquid)) ○Phoret SCS: (trade name: styrene-based acrylic polymer manufactured by Soken Chemical Co., Ltd. (Tg: 70°C, weight average molecular weight: 15,000)) ○BMI-1: (trade name, manufactured by Tokyo Chemical Industry Co., Ltd., 4,4'-bismaleimide diphenylmethane) ○TPPK: (Trade name: Tetraphenylphosphonium tetraphenylborate manufactured by Tokyo Chemical Industry Co., Ltd.) ○HP-P1: (trade name, manufactured by Mizushima Alloy Iron Co., Ltd., boron nitride filler)

(Synthesis example 1) <Preparation of resin solution A for adhesive layer> Cyclohexanone was added to a composition containing (a) an epoxy resin and a phenol resin as thermosetting resins and (c) an inorganic filler with the product names and composition ratios (unit: parts by mass) in Table 1, and the mixture was stirred. . The acrylic rubber as the (b) high molecular weight component shown in Table 1 was added thereto and stirred. Furthermore, the (e) coupling agent and (d) hardening accelerator shown in Table 1 were added and stirred until each component became Until it becomes uniform, the resin solution A for the adhesive layer is obtained.

[Table 1] Classification Name Synthesis example 1 Epoxy resin R710 twenty four VG3101L twenty one SR35K 20 YDCN-700-10 1.4 Phenolic resin Milex XLC-LL 1.2 HE910-10 17 HE200C-10 15 Inorganic filler Aerosil R972 0.82 SC1030-HJA 61 Coupling agent A-189 0.29 A-1160 0.59 hardening accelerator Curezol 2PZ-CN 0.025 acrylic rubber HTR-860P-30B-CHN 27 HTR-860P-3CSP 12

(Synthesis example 2) ＜Synthesis of polyimide resin (PI-1) and preparation of resin solution B for adhesive layer＞ 1,3-Bis(3-aminopropyl)tetramethyldisiloxane (manufactured by Shin-Etsu Chemical Industry Co., Ltd., commercial product) was placed in a 300 mL flask equipped with a thermometer, a stirrer, a cooling tube, and a nitrogen gas inflow tube. Name: LP-7100) 15.53 g, polyoxypropylene diamine (manufactured by BASF Co., Ltd., trade name: D400, molecular weight: 450) 28.13 g, and NMP 100.0 g were stirred to prepare a reaction solution. After the diamine is dissolved, 4,4'-oxydiphthalic dianhydride, which has been previously purified by recrystallization from anhydrous acetic acid, is added to the reaction solution in small amounts while cooling the flask in an ice bath. 32.30g. After reacting at normal temperature (25°C) for 8 hours, 67.0 g of xylene was added, and the mixture was heated at 180°C while blowing nitrogen gas, thereby azeotropically removing the xylene and water. The reaction liquid was poured into a large amount of water, and the precipitated resin was collected by filtration and dried to obtain polyimide resin (PI-1). The molecular weight of the obtained polyimide resin (PI-1) was measured using gel permeation chromatography (GPC). As a result, in terms of polystyrene conversion, the number average molecular weight Mn=22400 and the weight average molecular weight Mw =70200. The obtained polyimide resin (PI-1) was used to prepare each component at the composition ratio (unit: parts by mass) shown in Table 2 to obtain a resin solution B for the adhesive layer.

[Table 2] Classification Name Synthesis example 2 thermoplastic resin PI-1 100 reactive plasticizer RE-810NM 40 Compounds with styrene group Phoret SCS 40 Compounds with maleimide groups BMI-1 40 hardening accelerator TPPK 0.2 Inorganic filler HP-P1 twenty two Solvent NMP 270

(Synthesis example 3) <Preparation of resin solution C for adhesive layer> Put 44.92 g of BTDA (0.139 mol) into a 500 mL four-necked flask equipped with a nitrogen inlet tube, a stirrer, a thermocouple, a Dean-Stark trap, and a cooling tube. 75.08 g of DDA (0.141 mole), 168 g of NMP and 112 g of xylene were mixed at 40°C for 30 minutes to prepare a polyamic acid solution. The polyamide solution was heated to 190° C., heated and stirred for 4 hours, and the distilled water and xylene were removed from the system. Thereafter, the solution was cooled to 100°C, 112 g of xylene was added and stirred, and further cooled to 30°C to complete the imidization to obtain a resin solution C for the adhesive layer (solid content: 29.5% by weight, weight average molecular weight :75,700).

(Synthesis example 4) <Preparation of resin solution D for adhesive layer> Let 42.51 g of BPADA (0.082 mole), 34.30 g of DDA (0.066 mole), 6.56 g of BAPP (0.016 mole), 208 g of NMP and 112 g of xylene be used as the raw material composition. In addition, The same procedure as in Synthesis Example 3 was carried out to prepare a polyamide solution. The polyamic acid solution was processed in the same manner as in Synthesis Example 3 to obtain a resin solution D for an adhesive layer (solid content: 30.0% by weight, weight average molecular weight: 65,000).

(Synthesis example 5) <Preparation of polyamide solution 1 for insulating resin layer> Under nitrogen flow, 64.20 g of m-TB (0.302 mole), 5.48 g of bisaniline-M (0.016 mole) and DMAc in an amount such that the post-polymerization solid content concentration was 15% by weight were put into the reaction tank. Stir and dissolve at room temperature. Next, 34.20 g of PMDA (0.157 mol) and 46.13 g of BPDA (0.157 mol) were added, and then the polymerization reaction was continued at room temperature for 3 hours to prepare polyamide solution 1 (viscosity: 26,500 cps ).

(Synthesis example 6) <Preparation of polyamide solution 2 for insulating resin layer> 69.56 g of m-TB (0.328 mole), 542.75 g of TPE-R (1.857 mole), DMAc in an amount such that the solid concentration after polymerization is 12% by weight, 194.39 g of PMDA (0.891 mole) and Except having used 393.31 g of BPDA (1.337 mol) as the raw material composition, it was carried out similarly to Synthesis Example 3, and polyamic acid solution 2 (viscosity: 2,650 cps) was prepared.

(Production example 1) <Preparation of resin sheet A for adhesive layer> Apply the resin solution A for the adhesive layer to the silicone-treated surface of the release base material (length × width × thickness = 320 mm × 240 mm × 25 μm) so that the thickness after drying is 50 μm. , the resin sheet A was prepared by heating and drying at 80° C. for 15 minutes, further drying at 120° C. for 15 minutes, and then peeling it off from the release base material. In addition, in order to evaluate the physical properties after hardening, the resin sheet A was heated in an oven at 120°C for 2 hours and at 170°C for 3 hours. At this time, the cured resin sheet A has a Tg of 95°C, a storage elastic modulus at 50°C of 960 MPa, and a maximum storage elastic modulus in the range of 180°C to 260°C of 7 MPa.

(Production example 2) <Preparation of resin sheet B for adhesive layer> Apply the resin solution B for the adhesive layer to the silicone-treated surface of the release base material (length × width × thickness = 320 mm × 240 mm × 25 μm) so that the thickness after drying is 50 μm. , the resin sheet B was prepared by heating and drying at 80° C. for 15 minutes, further drying at 120° C. for 15 minutes, and then peeling it off from the release base material. In addition, in order to evaluate the physical properties after hardening, the resin sheet B was heated in an oven at 120° C. for 2 hours and at 170° C. for 3 hours. At this time, the cured resin sheet B has a Tg of 100°C or less, a storage elastic modulus at 50°C of 1800 MPa or less, and a maximum storage elastic modulus in the range of 180°C to 260°C of 70 MPa.

(Production example 3) <Preparation of resin sheet C for adhesive layer> Mix 1.8 g of N-12 (0.0036 mol) and 12.5 g of OP935 into 169.49 g of the resin solution C for the adhesive layer (50 g in terms of solid content), and add 6.485 g of NMP and 19.345 g of Dilute with xylene to prepare polyimide varnish 1.

Apply polyimide varnish 1 to the silicone-treated surface of the release base material (length × width × thickness = 320 mm × 240 mm × 25 μm) so that the thickness after drying is 50 μm, and then The resin sheet C was prepared by heating and drying at 80° C. for 15 minutes and peeling it from the release base material. The Tg of the resin sheet C is 78°C, the storage elastic modulus at 50°C is 800 MPa, and the maximum value of the storage elastic modulus in the range of 180°C to 260°C is 10 MPa. In addition, the dielectric constant (Dk) and dielectric loss tangent (Df) are 2.68 and 0.0028 respectively.

(Production example 4) <Preparation of resin sheet D for adhesive layer> Apply the resin solution D for the adhesive layer to the silicone-treated surface of the release base material (length × width × thickness = 320 mm × 240 mm × 25 μm) so that the thickness after drying is 50 μm. , heated and dried at 80° C. for 15 minutes, and peeled off from the release base material, thereby preparing a resin sheet D. The Tg of the resin sheet D is 82°C, the storage elastic modulus at 50°C is 1800 MPa or less, and the maximum value of the storage elastic modulus in the range of 180°C to 260°C is 2 MPa or less. In addition, the dielectric constant (Dk) and dielectric loss tangent (Df) are 2.80 and 0.0026 respectively.

(Production example 5) ＜Preparation of single-sided metal-clad laminate＞ On copper foil 1 (electrolytic copper foil, thickness: 12 μm, surface roughness Rz on the resin layer side: 0.6 μm), the polyamide solution is evenly applied so that the thickness after hardening is about 2 μm to 3 μm. 2. Then, heat and dry at 120°C to remove the solvent. Next, the polyamide solution 1 was evenly coated on it so that the thickness after hardening would be about 21 μm, and the solution was heated and dried at 120° C. to remove the solvent. Furthermore, the polyamide solution 2 is uniformly coated thereon so that the thickness after hardening is about 2 μm to 3 μm, and then heated and dried at 120° C. to remove the solvent. Furthermore, stepwise heat treatment is performed from 120°C to 360°C to complete the imidization, and a single-sided metal-clad laminate 1 is prepared. The dimensional change rate of the single-sided metal-clad laminate 1 is as follows. Dimensional change rate after etching in MD direction (long side direction): 0.01% Dimensional change rate after etching in TD direction (width direction): -0.04% Dimensional change rate after heating in MD direction (long side direction): -0.03% Dimensional change rate after heating in TD direction (width direction): -0.01% In addition, the polyimide film 1 (thickness: 25 μm) prepared by etching and removing the copper foil 1 of the single-sided metal-clad laminate 1 using an aqueous ferric chloride solution has a CTE of 20.0 ppm/K and a dielectric constant (Dk) and dielectric loss tangent (Df) are 3.40 and 0.0029 respectively.

[Example 1] The resin solution A for the adhesive layer is applied to the resin surface of the single-sided metal-clad laminate 1 so that the dried thickness is 50 μm, and then heated and dried at 80°C for 15 minutes, and then dried at 120°C. Drying was performed for 15 minutes, thereby preparing a single-sided metal-clad laminate 1 with an adhesive layer. In addition, in order to evaluate the physical properties of the single-sided metal-clad laminate 1 with an adhesive layer after hardening of the adhesive layer, it was heated in an oven at 120°C for 2 hours and at 170°C for 3 hours. The evaluation results of the heated single-sided metal-clad laminate 1 with an adhesive layer are as follows. Dimensional change rate after etching in MD direction: -0.05% Dimensional change rate after etching in TD direction: -0.02% Dimensional change rate after heating in MD direction: -0.01% Dimensional change rate after heating in TD direction: -0.03% There is no problem in the dimensional change of the single-sided metal-clad laminate 1 with an adhesive layer after heating. In addition, the CTE of the resin laminate 1 (thickness: 75 μm) prepared by etching and removing the copper foil 1 of the heated single-sided metal-clad laminate 1 with an adhesive layer was 26.2 ppm/K.

[Example 2] The resin solution B for the adhesive layer is applied to the resin surface of the single-sided metal-clad laminate 1 so that the thickness after drying is 50 μm, and then heated and dried at 80°C for 15 minutes, and then dried at 120°C. Drying was performed for 15 minutes, thereby preparing a single-sided metal-clad laminate 2 with an adhesive layer. In addition, in order to evaluate the physical properties of the single-sided metal-clad laminate 2 with an adhesive layer after hardening of the adhesive layer, it was heated in an oven at 120° C. for 2 hours and at 170° C. for 3 hours. The evaluation results of the heated single-sided metal-clad laminate 2 with an adhesive layer are as follows. Dimensional change rate after etching in MD direction: -0.08% Dimensional change rate after etching in TD direction: -0.06% Dimensional change rate after heating in MD direction: -0.03% Dimensional change rate after heating in TD direction: -0.06% There is no problem in the dimensional change of the heated single-sided metal-clad laminate 2 with an adhesive layer. In addition, the CTE of the resin laminate 2 (thickness: 75 μm) prepared by etching and removing the copper foil 1 of the heated single-sided metal-clad laminate 2 with an adhesive layer was 25.0 ppm/K.

[Example 3] The polyimide varnish 1 is applied to the resin surface of the single-sided metal-clad laminate 1 so that the thickness after drying is 50 μm, and then heated and dried at 80°C for 15 minutes to prepare an adhesive layer. Single-sided metal-clad laminate 3. In addition, the single-sided metal-clad laminated board 3 with an adhesive layer was heated in an oven at 180° C. for 1 minute and at 150° C. for 30 minutes, and then evaluated. The results were as follows. Dimensional change rate after etching in MD direction: -0.05% Dimensional change rate after etching in TD direction: -0.04% Dimensional change rate after heating in MD direction: 0.05% Dimensional change rate after heating in TD direction: 0.01% There is no problem in the dimensional change of the single-sided metal-clad laminate 3 with an adhesive layer after heating. In addition, the resin laminate 3 (thickness: 75 μm) prepared by etching and removing the copper foil 1 of the heated single-sided metal-clad laminate 3 with an adhesive layer has a CTE of 25.6 ppm/K and a dielectric constant (Dk ) and dielectric loss tangent (Df) are 2.92 and 0.0028 respectively.

[Example 4] The resin solution D for the adhesive layer is applied to the resin surface of the single-sided metal-clad laminate 1 so that the thickness after drying is 50 μm, and then heated and dried at 80°C for 15 minutes to prepare an adhesive tape. The single-sided metal-clad laminate 4 of the connecting layer. In addition, the single-sided metal-clad laminate 4 with an adhesive layer was evaluated after being heated in an oven at 180°C for 1 minute and at 150°C for 30 minutes. As a result, there was no problem with dimensional changes, and the dielectric constant ( Dk) and dielectric loss tangent (Df) are 3.00 and 0.0027 respectively.

[Example 5] Let the liquid crystal polymer film (manufactured by Kuraray, trade name: CT-Z, thickness: 25 μm, CTE: 18 ppm/K, heat distortion temperature: 300°C, Dk: 3.40, Df: 0.0022) be As an insulating base material, a double-sided metal laminated board 1 with copper foil 1 provided on both sides of the base material was prepared. The copper foil 1 on one side of the double-sided metal-clad laminate 1 is etched and removed to prepare a single-side metal-clad laminate 2 .

The polyimide varnish 1 is applied to the resin surface of the single-sided metal-clad laminate 2 so that the thickness after drying is 50 μm, and then heated and dried at 80°C for 15 minutes to prepare an adhesive layer. Single-sided metal-clad laminate 5. In addition, the single-sided metal-clad laminate 5 with an adhesive layer was evaluated after being heated in an oven at 180°C for 1 minute and at 150°C for 30 minutes. As a result, there was no problem with dimensional changes, and the dielectric constant ( Dk) and dielectric loss tangent (Df) are 2.92 and 0.0026 respectively.

[Example 6] The resin solution D for the adhesive layer is applied to the resin surface of the single-sided metal-clad laminate 2 so that the dried thickness is 50 μm, and then heated and dried at 80° C. for 15 minutes to prepare an adhesive tape. The single-sided metal-clad laminate 6 is connected. In addition, the single-sided metal-clad laminate 6 with an adhesive layer was evaluated after being heated in an oven at 180°C for 1 minute and at 150°C for 30 minutes. As a result, there was no problem with dimensional changes, and the dielectric constant ( Dk) and dielectric loss tangent (Df) are 3.00 and 0.0025 respectively.

[Example 7] The copper foil 1 of the single-sided metal-clad laminated board 1 is subjected to circuit processing by a subtractive method to prepare a single-sided wiring board 1 on which a conductor circuit layer is formed. The copper foils 1 of the two single-sided metal-clad laminates 3 with an adhesive layer are subjected to circuit processing using the subtractive method to prepare two single-sided wiring boards 1 with an adhesive layer on which conductor circuit layers are formed.

The conductor circuit layer of the single-sided wiring board 1 is connected to the adhesive layer of the single-sided wiring board 1 with an adhesive layer, and the conductor circuit layer of the single-sided wiring board 1 with an adhesive layer is connected to another adhesive layer. After the adhesive layers of the single-sided wiring board 1 are stacked facing each other, they are thermally compressed for 60 minutes under conditions of 160°C and 4 MPa, thereby preparing a multilayer circuit board 1 . In the crimping surface of the multilayer circuit substrate 1, the adhesive is fully filled into the conductor circuit layer, and there is no disorder of the conductor circuit caused by the thermal crimping step.

[Example 8] Prepare two single-sided wiring substrates 1 with adhesive layers, and place the adhesive layer of one single-sided wiring substrate 1 with an adhesive layer and the adhesive layer of the other single-sided wiring substrate 1 with an adhesive layer so as to face each other. After overlapping, the two-sided circuit substrate 1 was prepared by thermocompression bonding for 60 minutes under the conditions of 160°C and 4 MPa. In the crimping surfaces of the two-sided circuit substrate 1, the adhesive layers are fully adhered to each other, and there is no disorder of the conductor circuit caused by the thermal crimping step.

[Example 9] The copper foil 1 of the two single-sided metal-clad laminates 4 with an adhesive layer is subjected to circuit processing using a subtractive method to prepare two single-sided wiring boards 2 with an adhesive layer on which conductor circuit layers are formed.

The conductor circuit layer of the single-sided wiring board 1 and the adhesive layer of the single-sided wiring board 2 with an adhesive layer are connected, and the conductor circuit layer of the single-sided wiring board 2 with an adhesive layer is connected to another adhesive layer. After the adhesive layers of the single-sided wiring board 2 are stacked facing each other, they are thermally compressed for 60 minutes under the conditions of 160°C and 4 MPa, thereby preparing the multilayer circuit board 2 . In the crimping surface of the multilayer circuit substrate 2, the adhesive is fully filled into the conductor circuit layer, and there is no disorder of the conductor circuit caused by the thermal crimping step.

[Example 10] Prepare two single-sided wiring substrates 2 with adhesive layers, and place the adhesive layer of one single-sided wiring substrate 2 with an adhesive layer and the adhesive layer of the other single-sided wiring substrate 2 with an adhesive layer so as to face each other. After overlapping, the two-sided circuit substrate 2 was prepared by thermocompression bonding for 60 minutes under the conditions of 160°C and 4 MPa. In the crimping surfaces of the double-sided circuit substrate 2, the adhesive layers are fully adhered to each other, and there is no disorder of the conductor circuit caused by the thermal crimping step.

[Example 11] The copper foil 1 of the single-sided metal-clad laminated board 2 is subjected to circuit processing by a subtractive method to prepare a single-sided wiring board 2 on which a conductive circuit layer is formed. The copper foils 1 of the two single-sided metal-clad laminates 5 with an adhesive layer are subjected to circuit processing using a subtractive method to prepare two single-sided wiring boards 3 with an adhesive layer on which conductor circuit layers are formed.

The conductor circuit layer of the single-sided wiring board 2 and the adhesive layer of the single-sided wiring board 3 with an adhesive layer are connected, and the conductor circuit layer of the single-sided wiring board 3 with an adhesive layer is connected to another adhesive layer. After the adhesive layers of the single-sided wiring board 3 are stacked facing each other, they are thermally compressed for 60 minutes under the conditions of 160°C and 4 MPa, thereby preparing the multilayer circuit board 3 . In the crimping surface of the multilayer circuit substrate 3, the adhesive is fully filled into the conductor circuit layer, and there is no disorder of the conductor circuit caused by the thermal crimping step.

[Example 12] Prepare two single-sided wiring substrates 3 with adhesive layers, and place the adhesive layer of one single-sided wiring substrate 3 with an adhesive layer and the adhesive layer of the other single-sided wiring substrate 3 with an adhesive layer so as to face each other. After overlapping, the two-sided circuit substrate 3 was prepared by thermocompression bonding for 60 minutes under the conditions of 160°C and 4 MPa. In the crimping surfaces of the two-sided circuit substrates 3, the adhesive layers are fully adhered to each other, and there is no disorder of the conductor circuit caused by the thermal crimping step.

[Example 13] The copper foil 1 of the two single-sided metal-clad laminates 6 with an adhesive layer is subjected to circuit processing using a subtractive method to prepare two single-sided wiring boards 4 with an adhesive layer on which conductor circuit layers are formed.

The conductor circuit layer of the single-sided wiring board 2 and the adhesive layer of the single-sided wiring board 4 with an adhesive layer are connected, and the conductor circuit layer of the single-sided wiring board 4 with an adhesive layer is connected to another adhesive layer. After the adhesive layers of the single-sided wiring board 4 are stacked facing each other, they are thermally compressed for 60 minutes under conditions of 160°C and 4 MPa, thereby preparing a multilayer circuit board 4 . In the crimping surface of the multilayer circuit substrate 4, the adhesive is fully filled into the conductor circuit layer, and there is no disorder of the conductor circuit caused by the thermal crimping step.

[Example 14] Prepare two single-sided wiring substrates 4 with adhesive layers, and place the adhesive layer of one single-sided wiring substrate 4 with an adhesive layer and the adhesive layer of the other single-sided wiring substrate 4 with an adhesive layer so as to face each other. After overlapping, the two-sided circuit substrate 4 was prepared by thermocompression bonding for 60 minutes under the conditions of 160°C and 4 MPa. In the crimping surfaces of the double-sided circuit substrate 4, the adhesive layers are fully adhered to each other, and there is no disorder of the conductor circuit caused by the thermal crimping step.

The embodiments of the present invention have been described in detail for the purpose of illustration. However, the present invention is not limited to the embodiments and can be modified in various ways.

10: Insulating resin layer 20:Metal layer 30: Adhesive layer 40:Single-sided metal clad laminate 50: Conductor circuit layer 100:Metal clad laminate 101:Circuit substrate 102:Circuit base unit 110: Any circuit board 200, 201: Multilayer circuit substrate T1:Total thickness T2, T3: thickness

FIG. 1 is a cross-sectional view showing the structure of a metal-clad laminated board according to an embodiment of the present invention. 2 is a cross-sectional view showing the structure of a circuit board according to an embodiment of the present invention. 3 is a cross-sectional view showing the structure of the multilayer circuit board according to the first embodiment of the present invention. 4 is an explanatory diagram showing the manufacturing steps of the multilayer circuit board according to the first embodiment of the present invention. 5 is a cross-sectional view showing the structure of a multilayer circuit board according to a second embodiment of the present invention. 6 is an explanatory diagram showing the manufacturing steps of the multilayer circuit board according to the second embodiment of the present invention.

10: Insulating resin layer

20:Metal layer

30: Adhesive layer

50: Conductor circuit layer

100:Metal clad laminate

101:Circuit substrate

102:Circuit base unit

201:Multilayer circuit substrate

Claims (4)

A method for manufacturing a multilayer circuit substrate, including: The step of preparing a plurality of circuit substrates, the circuit substrates including an insulating resin layer, a conductor circuit layer formed on one side of the insulating resin layer, and an adhesive layer laminated on the other side of the insulating resin layer; and The step of overlapping and pressing the adhesive layer of one of the circuit substrates and the adhesive layer of the other circuit substrate in a facing manner. The manufacturing method of a multilayer circuit substrate as claimed in claim 1, wherein the resin constituting the adhesive layer is an adhesive polyimide containing tetracarboxylic acid residues and diamine residues, and The adhesive polyimide contains 50 mole parts or more of a diamine residue derived from a dimer acid-type diamine relative to 100 mole parts of the total amount of the diamine residues, and the dimer Acid-type diamine is formed by substituting the two terminal carboxylic acid groups of dimer acid with primary aminomethyl or amino groups. The manufacturing method of a multilayer circuit board according to claim 2, wherein the adhesive polyimide contains a total of 90 mole parts or more relative to 100 mole parts of the total amount of the tetracarboxylic acid residues. Tetracarboxylic acid residue derived from tetracarboxylic anhydride represented by the following general formula (1) and/or general formula (2): In the general formula (1), A cyclic saturated hydrocarbon group in a membered ring, a 7-membered ring or an 8-membered ring, In the formula, Z represents -C ₆ H ₄ -, -(CH ₂ )n- or -CH ₂ -CH(-OC(=O)-CH ₃ )-CH ₂ -, and n represents an integer from 1 to 20 . The manufacturing method of a multilayer circuit substrate according to claim 2, wherein the adhesive polyimide is between 50 and 99 mole parts relative to 100 mole parts of the total amount of the diamine residues. The diamine residue derived from the dimer acid type diamine is contained within the range of 1 molar part or less and 50 molar parts or less and is selected from the following general formula (B1) to A diamine residue derived from at least one diamine compound among the diamine compounds represented by general formula (B7): In the formulas (B1) to (B7), R ₁ independently represents a monovalent hydrocarbon group or an alkoxy group having 1 to 6 carbon atoms, and the linking group A independently represents a group selected from -O-, -S-, -CO-, The divalent group in -SO-, -SO ₂ -, -COO-, -CH ₂ -, -C(CH ₃ ) ₂ -, -NH- or -CONH-, n ₁ independently represents an integer from 0 to 4 ; Among them, the part that is repeated with the formula (B2) is removed from the formula (B3), and the part that is repeated with the formula (B4) is removed from the formula (B5).