JP5214106B2 - Thermosetting adhesive film and multilayer printed circuit board produced using them - Google Patents

Description

The present invention relates to a thermosetting adhesive film useful for forming an interlayer insulating resin layer of a multilayer printed wiring board and a multilayer printed circuit board produced using the same, and in particular, a conductive circuit layer and an insulating resin layer are alternately stacked. the multilayer printed wiring board of the build-up method with good productivity comprising Te, and good workability can be manufactured, even lower water absorption and low dielectric constant, low dielectric thermosetting resin composition capable of producing a flame-retardant multilayer printed board of tangent The present invention relates to a thermosetting adhesive film using

  Conventionally, multilayer printed wiring boards have one or more prepreg sheets that are semi-cured by impregnating an epoxy resin into a glass cloth base material on an inner layer circuit board on which a circuit is formed, and a copper foil is further stacked thereon. It was manufactured through a process of heat-pressing with a hot plate press machine and integrally forming.

  Furthermore, in recent years, a manufacturing technique of a multilayer printed wiring board by a build-up method that enables high-density wiring has attracted attention. For example, an epoxy resin composition is applied to an inner layer circuit board on which a circuit is formed, heat-cured, a roughened surface is formed on the surface with a roughening agent, and a conductor layer is formed by plating. A method of manufacturing a wiring board has been proposed (see Japanese Patent Laid-Open Nos. 7-304931 and 7-304933). In addition, an epoxy resin adhesive sheet is laminated to the inner layer circuit board on which the circuit is formed, heat-cured, a roughened surface is formed on the surface with a roughening agent, and a conductor layer is formed by plating. A method for manufacturing a wiring board has also been proposed (see JP-A-11-87927). However, in any of the above-described methods, a material mainly composed of an epoxy resin is used, and at present, sufficient characteristics are not obtained with respect to low dielectric constant, low dielectric loss tangent, and low water absorption. .

  On the other hand, introduction of an imide skeleton considered to be useful for heat resistance and low dielectric constant has also been attempted. For example, a thermosetting composition for build-up using an aromatic diamine having an imide group and an epoxy resin is proposed. However, the dielectric constant is not discussed. In addition, even when viewed from the study cases of the present inventors, when a low molecular weight polyimide compound is used as a curing agent for an epoxy resin, most of the heat resistance and low dielectric properties as polyimide cannot be obtained. There are many cases that do not change. On the other hand, when a high molecular weight imide compound is used as a curing agent for an epoxy resin, the compatibility is poor and separation is almost the case.

  In general, polyimide resins are used in various industries because of their heat resistance and dielectric characteristics, but they are often poorly soluble in solvents alone and are rarely provided as liquid thermosetting compositions. . Further, even if provided, it was almost always separated or precipitated when the solid content was low, or when other resin such as epoxy resin or phenol resin, or inorganic filler was blended.

  For this reason, polyimide resins are generally used as polyimide films, but most of them are films made of polyimide alone. For example, high-temperature treatment is required for heat treatment to develop adhesiveness. That is, the commercially available polyimide film is (a) a film formed of a polyimide alone, (b) a polyimide film coated with a rubber-based or acrylic pressure-sensitive adhesive (adhesive), and (c) a polyimide solution. Cast on a metal sheet such as copper foil, or sputtered metal on an imide film, and further formed a metal support by plating, but the film of (a) above has no adhesion and is above the softening point It can only be heated and crimped. Furthermore, the softening point of the polyimide is usually as high as 250 ° C. and cannot be used for printed wiring board applications. In the case of the film (b), it can be bonded at a relatively low temperature, but the physical property value of the adhesive (adhesive) layer is extremely different from that of polyimide, and the excellent properties of polyimide are sufficient as an insulating layer. It is not demonstrated. In the case of the film (c), there is a problem that the film cannot be pressure-bonded unless it is at a high temperature of 250 ° C. or higher as in the film (a).

  In recent years, printed wiring boards are rapidly changing from conventional halogen-based flame retardants to non-halogen-based flame retardants in consideration of environmental impact. However, although most non-halogen flame retardants have sufficient properties in terms of flame retardancy, they actively improve solder heat resistance, water absorption, dielectric constant, and dielectric loss tangent as printed wiring boards. Rather, there was a concern that the characteristics were deteriorated, and the use amount was limited in most cases.

The present invention has been made in order to solve the above-described problems of the prior art, and its main purpose is to have sufficient adhesion to a conductor and to have high heat resistance, flame retardancy, and low dielectric constant. An object of the present invention is to provide a thermosetting adhesive film using a thermosetting resin composition capable of forming an interlayer insulating resin layer having a low rate, low dielectric loss tangent, and low water absorption.

  Another object of the present invention is a thermosetting adhesive which can be laminated at a relatively low temperature, has sufficient adhesion to a conductor, and can form an interlayer insulating resin layer having the above-mentioned excellent characteristics. To provide a film.

Still another object of the present invention is to provide a high-performance, high-density multilayer printed circuit board that can be manufactured with good workability using the thermosetting adhesive film as described above.

In order to achieve the above object , according to the present invention, (A) a linear hydrocarbon having a carboxyl group or an acid anhydride group and having a number average molecular weight of 700 to 4,500 on a support base film. Polyimide resin having structure, urethane bond, imide ring, and isocyanurate ring, (B) epoxy resin, and 2-ethyl-4-methylimidazole, 2-methylimidazole, 2-phenyl as epoxy resin curing agent Imidazole, 2-phenyl-4-methylimidazole, bis (2-ethyl-4-methyl-imidazole), 2-phenyl-4-methyl-5-hydroxymethylimidazole, 2-phenyl-4,5-dihydroxymethylimidazole, containing an imidazole compound selected from the group consisting of triazine addition type imidazole as essential components Film made from the curable resin composition is a thermosetting adhesive film characterized by being formed in a semi-cured state is provided. The semi-cured state here means a solid that is solid at room temperature and fluidizes in a heated state.

  In a preferred embodiment, the polyimide resin (A) has a structural unit represented by the following general formula (1) and a structural unit represented by the general formula (2), and the general formula (3), ( 4) A polyimide resin having at least one of the terminal structures represented by (5). The polyimide resin (A) is a polyimide resin having an acid value of 20 to 150 mgKOH / g, and the mass ratio (A) / (B) between the polyimide resin (A) and the epoxy resin (B) is 0.00. It is preferable that it is 1-10.

In a preferred embodiment of the thermosetting resin composition of the present invention, contain organic solvent (C), it is preferred in particular derivatives of ethylene glycol or propylene glycol. Moreover, from the point of the applicability | paintability of a thermosetting resin composition, ratio of the viscosity of 5 rpm of rotations, and the viscosity of 50 rpm of rotation of the said composition measured with the rotational viscometer is 1.1 or more Is preferred.

Furthermore, in a preferred embodiment of the thermosetting adhesive film of the present invention, film is formed by using more compounds having a phenolic hydroxyl group at least two thermosetting resin composition containing (D).

Further according to the invention, a multilayer printed circuit board before Symbol thermosetting adhesive film with interlayer insulating resin layer is formed is provided.

The thermosetting resin composition of the present invention has sufficient adhesion to a conductor and can form an interlayer insulating resin layer having high heat resistance, flame retardancy, low dielectric constant, low dielectric loss tangent, and low water absorption. . Similarly, the thermosetting adhesive film according to the present invention contains, on the support base film, the polyimide resin (A), the epoxy resin (B), and an imidazole compound as an epoxy resin curing agent as essential components. Since the film made of the curable resin composition is formed in a semi-cured state, it can be laminated at a relatively low temperature, has sufficient adhesion to the conductor, and has the above-mentioned characteristics. An excellent interlayer insulating resin layer can be formed with good workability. Thus, by using a thermosetting adhesive film that written, high performance can be produced with good workability and high-density multilayer printed circuit board.

  The inventors of the present invention provide a thermosetting resin composition satisfying high heat resistance, flame retardancy, low dielectric constant, and sufficient adhesion with a conductor as an interlayer insulating resin layer of a multilayer printed wiring board, or at a relatively low temperature. As a result of intensive studies on the thermosetting adhesive film that can be laminated with, the thermosetting resin composition or the thermosetting adhesive film has good workability, and the multilayer printed wiring board using this is extremely excellent. It has been found that it has performance, and the present invention has been completed.

That is, the thermosetting resin composition according to the present invention has (A) a linear hydrocarbon structure having a carboxyl group or an acid anhydride group and having a number average molecular weight of 700 to 4,500, a urethane bond, wherein the imide ring, a polyimide resin having an isocyanurate ring, in that it contains as epoxy resin (B), (C) essential components the imidazole compound as a boiling point of 100 ° C. or more organic solvents, and epoxy resin curing agent By using the resin composition, the interlayer insulating resin layer having sufficient adhesion to the conductor and having high heat resistance, flame retardancy, low dielectric constant, low dielectric loss tangent, and low water absorption is worked. It can be formed with good properties.

Moreover, the thermosetting adhesive film which concerns on this invention contains the said polyimide resin (A), an epoxy resin (B), and the said imidazole compound as an epoxy resin hardening | curing agent as an essential component on a support base film. Since the film made of the curable resin composition is formed in a semi-cured state, it can be laminated at a relatively low temperature, has sufficient adhesion to the conductor, and has excellent properties as described above. The interlayer insulating resin layer can be formed with good workability.

  Particularly important components in the thermosetting resin composition of the present invention include the above-mentioned carboxyl group or acid anhydride group, and a linear hydrocarbon structure having a number average molecular weight of 700 to 4,500, a urethane bond, It is a polyimide resin (A) having an imide ring and an isocyanurate ring, and its physical properties are unique to polyimide, but it exhibits toughness due to the presence of a linear hydrocarbon structure, and it has the same handling properties as an epoxy resin. And has the following important effects on the formed interlayer insulating resin layer.

  (A) The imide skeleton realizes high heat resistance and a high glass transition point Tg.

  (B) Since it has a carboxyl group or an acid anhydride group, it can react with an epoxy group, and can realize and improve adhesiveness, electrical characteristics, workability, and low-temperature curability, which are the characteristics of an epoxy resin.

  (C) Since it has a partially linear hydrocarbon structure, it can be selectively roughened with a commercially available desmear liquid, forming irregularities on the surface of the cured coating film, and being a strong anchor with the conductor layer Excellent adhesion due to the effect is exhibited.

  (D) Since it has a nitrogen-containing heterocyclic structure, it exhibits flame retardancy.

  (E) Low water absorption, low dielectric constant, and low dielectric loss tangent can be realized by the linear hydrocarbon structure and the imide skeleton.

  (F) When the polyimide resin contains an isocyanurate ring in particular, a polymer having a so-called hyperbranched polymer structure is formed, unlike a normal linear structure polyimide. For example, it is presumed that dendrimers having a carboxyl group or an acid anhydride group have a structure in which they are linked by a linear hydrocarbon structure. Therefore, although it is a polymer, it can be arbitrarily dissolved in an epoxy resin or an organic solvent, and its workability is similar to that of a low molecular compound or oligomer, and also has characteristics as a polymer material.

  The thermosetting resin composition according to the present invention includes an epoxy resin (B), a polyimide resin (A) that exhibits the above-described functions and effects, an organic solvent (C) having a boiling point of 100 ° C. or higher, and epoxy resin curing. In combination with the imidazole compound as an agent, combined with the effects of the epoxy resin as described above and the prevention of foaming at the time of drying the coating film and the viscosity change at the time of coating by using a high-boiling organic solvent And sufficient adhesion to the conductor. In addition, the thermosetting adhesive film according to the present invention has a film formed from a thermosetting resin composition containing the polyimide resin (A) that exhibits the above-described functions and effects in combination with the epoxy resin (B). Therefore, it can be laminated at a relatively low temperature and has sufficient adhesion to the conductor. In addition, it is possible to form an interlayer insulating resin layer having high heat resistance, flame retardancy, low dielectric constant, low dielectric loss tangent, and low water absorption with good workability.

  The thermosetting resin composition and the thermosetting adhesive film of the present invention are formed on the inner layer circuit board on which the circuit is formed by forming a resin insulating layer by a coating film forming process or a film laminating process, forming a hole, and forming a conductor layer. It can use suitably for the said resin insulation layer formation in the method of manufacturing a multilayer printed wiring board at least through a process.

  As a form of the method for producing the multilayer printed wiring board, for example, the thermosetting resin composition of the present invention is applied to an inner circuit board on which a circuit is formed and dried, or the thermosetting adhesive film of the present invention is applied. After laminating, heat curing as necessary, then drilling holes (via holes, through holes, etc.) with a drill or laser processing machine, and further conducting conductor plating on the holes and the dried coating film or film at least Apply the thermosetting resin composition to the first form that goes through and dry the thermosetting resin composition on the inner layer circuit board, or laminate the thermosetting adhesive film, and press or laminate the copper foil on the dried coating film or film And then heat-curing as necessary, then drilling with a drill or laser processing machine, plating the hole part and conducting with the inner layer circuit, then the surface layer Second form undergoing at least a step of patterning a conductor by etching, and the like are preferably employed.

  Hereinafter, a method for producing a multilayer printed wiring board using the thermosetting resin composition or the thermosetting adhesive film of the present invention will be described, and then the thermosetting resin composition and the thermosetting adhesive film of the present invention will be described in detail. explain.

  First, when a thermosetting resin composition is used, it is applied to an inner layer circuit board on which a circuit is formed by roller coating, screen printing, curtain coating, die coating or the like. At this time, the viscosity of the thermosetting resin composition is preferably in the range of about 0.1 to 400 dPa · s at 25 ° C., more preferably about 2 to 300 dPa · s. When the viscosity of the thermosetting resin composition is lower than the above range, a sufficient film thickness cannot be obtained. On the other hand, when the viscosity is higher than the above range, unevenness or streaks may occur in the coating film. However, it is not preferable because sometimes it cannot be applied.

  The thermosetting resin composition at this time has a ratio of the viscosity at a rotational speed of 5 rpm measured by a rotational viscometer to the viscosity at a rotational speed of 50 rpm is 1.1 or more, that is, the TI value is 1.1 or more. Preferably there is. More preferably, it is 1.1-2.0. When the TI value is smaller than 1.1, it is not preferable because sagging is likely to occur after coating. On the other hand, when the TI value exceeds 2.0, streaks are generated on the coating film or coating becomes impossible. For this reason, it is preferable to add a known and commonly used thixotropic agent such as asbestos, olben, benton and fine silica as necessary. Further, pigments, antifoaming agents, additives and the like can be added.

  In addition, the thermosetting resin composition within the range of the TI value can be performed in a state where the substrate is kept vertical also in the drying step after the coating step, saving space and preventing dust from adhering to the substrate. It is effective from the viewpoint. In this drying process, it is necessary to set the solvent so that it is sufficiently volatilized. For this purpose, a drying temperature of about 80 to 130 ° C. and a drying time of about 5 to 60 minutes are preferable. This is because if the drying temperature is less than 80 ° C., the solvent is insufficiently volatilized, while if the drying temperature exceeds 130 ° C., bumping may occur in the coating film and bubbles may remain.

  Next, in the first embodiment, post cure (final curing) is performed. The final curing temperature is preferably about 150 to 200 ° C. for 30 to 120 minutes. When the temperature is lower than the above conditions or when the time is short, the reaction (curing) becomes insufficient. On the other hand, when the temperature is high or the time is long, the inner substrate or the cured coating film is thermally deteriorated. , Electrical characteristics and mechanical characteristics may deteriorate.

Thereafter, the cured coating is polished as necessary. The purpose of polishing is
(1) Flatten the unevenness that occurs after coating and drying.
(2) Facilitate chemical attack in the surface roughening step performed after polishing (improve surface wettability),
(3) Reduce the film thickness to the desired thickness.
However, it may not be polished when it can be determined that it is not necessary, for example, when there is sufficient flatness or film thickness after curing. At this time, the types of polishing that can be used include a belt sander, a buff, and a nylon brush.

  On the other hand, when the thermosetting adhesive film of the present invention is used, the inner layer circuit board on which the circuit is formed is heat laminated with a vacuum film laminator and integrally formed. If necessary, it is preferable to heat laminate with a vacuum film laminator and then level (flatten) the film surface by heating and pressing with a hot plate press.

Here, the vacuum laminator used in the above process is capable of processing substrates one by one, having a temperature of about 70 to 180 ° C., a degree of vacuum of 5 Torr or less, eliminating a gap with the copper foil, and melting and adhering the resin. preferable. The hot plate press machine for leveling is also preferably an apparatus that can process one sheet at a time from a laminator and can apply a pressure of about 5 to 30 kg / cm ² at about 70 to 180 ° C. Further, the time for laminating and leveling is preferably within 30 seconds to 2 minutes, and both are preferably the same time because they can be processed continuously. Here, if it is less than 30 seconds, adhesion to the copper foil and leveling properties are not sufficient, while if it is 5 minutes or more, mass productivity is poor. Further, when flatness is not required, the leveling step can be omitted. Examples of apparatuses that can be used for these laminates include MVLP-500 manufactured by MEIKI, VA-720, VA-724, NPVA-1, and NPVA-24 manufactured by Morton. Under the present circumstances, the thermosetting adhesive film of this invention can also be adhere | attached through a prepreg or another adhesive sheet.

  In the above process, the adhesive film is re-melted by heating lamination using a vacuum film laminator, and strongly adhered to the inner layer circuit. In addition, unevenness due to the inner layer circuit on the surface of the adhesive film is eliminated when the adhesive film is heated and pressed by a hot plate press and leveled, and is cured as it is, so that a multilayered board with a flat surface state is finally obtained. It is done. And the board | substrate after heat lamination is finally hardened | cured by a hot air circulation type or a far infrared ray. The curing temperature at that time is 130 to 200 ° C., and a range of 30 to 120 minutes is appropriate. At this time, the support base film may be removed or may be removed as it is after curing.

Next, holes are made in the substrate on which the resin insulating layer made of a cured coating film or an adhesive film is formed as described above with a semiconductor laser such as a CO ₂ laser or a UV-YAG laser or a drill as necessary. . At this time, the hole is either a through hole (through hole) for the purpose of conducting the front and back of the substrate, or a partial hole (belly via) for the purpose of conducting the circuit of the inner layer and the circuit of the composition surface. But you can.

  After drilling, in order to remove the residue (smear) existing on the inner wall and bottom of the hole and to develop the anchor effect between the conductor (metal plating formed later), the formation of surface irregularities is a commercially available desmear liquid Simultaneously with (roughening agent). This step can also be performed by a dry process such as plasma.

Next, conductor plating is applied to the hole from which the residue has been removed with a desmear solution and the surface of the coating film with the unevenness caused by the chemical, thereby forming a circuit. As the method,
(1) Electroless metal plating is performed on the entire surface of the substrate, and a metal plating layer is formed by electrolytic plating. Then, a pattern of a commercially available negative pattern resist or positive pattern resist is formed according to the pattern to be formed. After that, by etching the metal, panel plating method to obtain the outermost conductor pattern,
(2) an additive method in which a permanent plating resist having a reverse pattern is formed on the surface of the coating film, and a conductive pattern is formed by electroless plating on a portion where the resist is not formed,
(3) Similar to the method of (1) above, after the electroless metal plating is applied to the entire substrate, a negative or positive plating resist pattern having a reverse pattern is formed. Thereafter, a plating layer is selectively formed on a portion where the resist pattern does not exist by electrolytic plating. Next, there is a semi-additive method in which the pattern resist is peeled and a conductive pattern is obtained by etching the electroless plating layer hidden in the pattern resist.

  In terms of versatility, the above method (1) is preferred. When fine patterning is required, the above methods (2) and (3) are preferred. In any method, after electroless plating, after electrolytic plating, or after both plating, heat treatment called annealing at about 80 to 180 ° C. for about 10 to 60 minutes for the purpose of removing stress of metal and improving strength. May be applied.

  The metal plating used here is not particularly limited, such as copper, tin, solder, nickel, etc., and can be used in combination. Further, instead of the plating used here, metal sputtering or the like can be used instead.

  In the second embodiment, a step of integrally molding the inner layer circuit board on which the dried coating film of the thermosetting resin composition is formed or the thermosetting adhesive film is laminated and the copper foil is required. Examples of the method include a laminating method and a pressing method as described below.

(1) Laminating method When a thermosetting resin composition is used, a copper foil or a resin-coated copper foil having a rough surface on one side or both sides on a dry coating film formed on a substrate is the first mode described above. Heat laminate with the vacuum film laminator described and integrally mold. If necessary, it is preferable to heat laminate the copper foil or resin-coated copper foil with a vacuum film laminator, and then heat and press the coating film with a hot plate press to level (flatten) it.

  Here, the time required for laminating and leveling is preferably within 30 seconds to 2 minutes, and both are preferably the same time because continuous treatment is possible. Here, if it is less than 30 seconds, adhesion to the copper foil and leveling properties are not sufficient, while if it is 5 minutes or more, mass productivity is poor. Further, when flatness is not required, the leveling step can be omitted. At this time, the copper foil can be bonded to the dry coating film via a prepreg or an adhesive sheet.

  On the other hand, when using a thermosetting adhesive film, the vacuum laminator shown in the first embodiment described above is used and similarly laminated on the inner layer circuit board. After laminating, the first form is heat-cured, but in the case of this second form, after the base film as a support is peeled off, the same laminating process is further performed on a copper foil having a rough surface on one side or both sides. Alternatively, the resin-coated copper foil is formed once again on the adhesive film. In addition, it is preferable to perform leveling (flattening) by heating and pressing with a hot plate press if necessary. At this time, the copper foil can be bonded to the thermosetting adhesive film via a prepreg or an adhesive sheet.

  In this process, the coated or dried coating film or adhesive film is re-melted by heating lamination using a vacuum film laminator, enters the rough surface of the copper foil, and adheres strongly due to its anchor effect, thereby providing sufficient peel strength. It will be obtained. In addition, the uneven surface due to the inner layer circuit of the coated and dried coating film or laminated adhesive film is eliminated when the coating film is heated and pressure leveled with a hot plate press machine, and is cured as it is. A surface-state multilayer board is obtained. And the board | substrate after the heat lamination of copper foil or copper foil with resin is finally hardened | cured by a hot-air circulation type or a far infrared ray. The curing temperature at that time is in the range of about 150 to 200 ° C. and about 30 to 120 minutes.

(2) Pressing method A copper foil having a rough surface on one side or both sides or a copper foil with resin is superposed on the dried coating film formed on the substrate, and is integrally formed by heating and pressing with a hot plate press. The pressing conditions vary somewhat depending on the performance of the machine, but are about 140 to 200 ° C. for about 1 to 4 hours and a pressure of about 15 to 50 kg / cm ² . At this time, the copper foil can be bonded to the dry coating film via a prepreg or an adhesive sheet.

  In this heating and pressurizing step, the coated and dried coating film is remelted by heating and pressing using a hot plate press and thermoset. At this time, the coating film enters the rough surface of the copper foil and is strongly bonded by the anchor effect, whereby a sufficient peel strength can be obtained. Further, the uneven surface due to the inner layer circuit of the coated and dried coating is eliminated when it is remelted, and is cured as it is, so that a multilayer plate having a flat surface state is finally obtained.

  As copper foil used in these steps, commercially available electrolytic copper foils such as JTC, JTC-AM, JTC-FM, and FTS manufactured by Furukawa Circuit Foil are used. It is preferable. More preferably, a copper foil having one surface or both surfaces roughened in advance is good, and the surface is further treated with various metal platings, or treated with a known and commonly used coupling agent or organic chelating agent. Is preferred. Moreover, it is preferable that the copper foil used here has a thickness of 9 μm or more and 18 μm or less. When a copper foil with a thickness of less than 9 μm is used, handling as a copper foil or a copper foil with resin is insufficient, and it is not preferable because it easily breaks during work. On the other hand, when it exceeds 18 μm, the weight of copper during stacking From the viewpoint of changing the film thickness or producing a high-performance printed circuit board intended for use, a thick copper foil is not preferable because it is disadvantageous for circuit formation.

A hole is made in the substrate thus obtained by using a semiconductor laser such as a CO ₂ laser or a UV-YAG laser or a drill. Especially when drilling with a CO ₂ laser, it is necessary to first etch the copper foil in the hole to be drilled to provide a guide, or to treat the copper foil so that the laser light is sufficiently absorbed by the copper foil. become. Also, the hole is a through-hole intended to connect the front and back of the board, and the circuit of the inner layer and the circuit of the resin insulation layer surface consisting of a dry paint film or adhesive film are intended to conduct. Either of the partial holes (belly vias) to be performed may be used.

  Next, a known and commonly used desmear treatment is performed for the purpose of conducting the holes, and then electroless copper plating and electrolytic copper plating are performed to form through holes, buried vias, or conformal vias, and copper foils on both sides And the copper foil and the inner layer circuit are conducted.

  Thereafter, a desired multilayer printed wiring board is obtained by etching the surface copper foil to form a pattern by a known pattern etching method used in the printed wiring board.

  Alternatively, it is also possible to form a circuit using a pattern resist after etching a laminated copper foil for the purpose of making a fine pattern of the circuit until it becomes thin. It is also possible to form a circuit by forming method (2) (additive method) or (3) (semi-additive method).

  Regardless of the first form and the second form, the multilayer printed wiring board obtained in this way is further multilayered by repeating the process, and a prepreg and a resin-coated copper foil are laminated to form a hot plate press machine. Multiple layers may be formed by heating and press forming.

  In the multilayer printed wiring board manufacturing method described above, as the inner layer substrate to be used, for example, a plastic substrate, a ceramic substrate, a metal substrate, a film substrate, or the like can be used. Specifically, a glass epoxy substrate or a glass polyimide can be used. A substrate, an alumina substrate, a low-temperature fired ceramic substrate, an aluminum nitride substrate, an aluminum substrate, a polyimide film substrate, or the like can be used. The inner layer circuit (wiring pattern) is preferably copper, and the copper circuit is preferably subjected to chemical surface treatment. On a circuit subjected to physical polishing such as buff polishing, the composition of the present invention has poor adhesion and may swell due to solder heat. As a suitable chemical treatment, a general-purpose blackening treatment or a treatment of forming a roughened surface by etching copper with a chemical, for example, Mec etch bond, Atotech bond film, McDermitt multi-bond, and the like are preferable. In particular, in the process of the present invention, there is a possibility that the inner layer copper circuit may be damaged at the time of coating or at the time of lamination, so the latter etching type surface treatment is excellent in that it is difficult to be damaged.

As described above, the thermosetting resin composition according to the present invention includes (A) a carboxyl group or an acid anhydride group, a linear hydrocarbon structure having a number average molecular weight of 700 to 4,500, a urethane bond, and an imide. polyimide resin having a ring and a isocyanurate ring, containing as the epoxy resin (B), (C) essential components the imidazole compound as a boiling point of 100 ° C. or more organic solvents, and epoxy resin curing agent.

On the other hand, the composition of the thermosetting adhesive film according to the present invention includes (A) a carboxyl group or an acid anhydride group, a linear hydrocarbon structure having a number average molecular weight of 700 to 4,500, and a urethane bond, as described above. If, polyimide resin having imide ring, an isocyanurate ring, containing as essential components the imidazole compound as (B) an epoxy resin, and an epoxy resin curing agent. Furthermore, the composition of the thermosetting adhesive film according to the present invention has a support film on at least one side. This is because the adhesive film of the present invention melts at a certain temperature and expresses adhesiveness, and thus functions as a cover when bonded. In other words, when adhering to both sides of the adhesive film, the side without the support film is closely attached to the non-adhesive body and adhered or temporarily adhered, and then the support film is peeled off and the non-adhesive body is further adhered and adhered. Can be realized. Further, when the adhesive film is stored and transported, a protective film can be used for the layer on the side opposite to the support film regardless of whether it is a sheet or a roll.

  Since the polyimide resin (A) used in the present invention is excellent in solubility and heat resistance in aprotic polar organic solvents such as general-purpose solvents such as ketone-based solvents, ester-based solvents, and ether-based solvents, a carboxyl group or an acid anhydride Polyimide resin (A1) having a physical group, a linear hydrocarbon structure having a number average molecular weight of 700 to 4,500, a urethane bond, an imide ring, and an isocyanurate ring, preferably further having a cyclic aliphatic structure Is preferred. The linear hydrocarbon structure is particularly preferably a linear hydrocarbon structure having a number average molecular weight of 800 to 4,200 because a polyimide resin having a good balance between flexibility and dielectric properties of the cured product can be obtained. .

Examples of the polyimide resin (A1) include a structural unit represented by the following general formula (1) and a structural unit represented by the following general formula (2), and the following general formulas (3) and (4). And a polyimide resin (A2) having any one or more of the terminal structures represented by (5). Among them, the acid value is 20 to 150 mgKOH / g, and the number average molecular weight is 700 to 4,500. The linear hydrocarbon structure has a content of 20 to 40% by mass, an isocyanurate ring concentration of 0.3 to 1.2 mmol / g, a number average molecular weight of 2,000 to 30,000, and a weight. A polyimide resin having an average molecular weight of 3,000 to 100,000 is more preferable.

  In the present invention, the acid value, the isocyanurate ring concentration, the number average molecular weight, and the weight average molecular weight of the polyimide resin (A) are measured by the following methods.

  (1) Acid value: Measured according to JIS K-5601-2-1. As a dilution solvent for the sample, a mixed solvent of acetone / water (9/1 volume ratio) with an acid value of 0 is used so that the acid value of the acid anhydride can also be measured.

(2) Concentration of isocyanurate ring: ¹³ C-NMR analysis [solvent: deuterated dimethyl sulfoxide (DMSO-d ₆ )] was performed, and a calibration curve was obtained from the spectral intensity of the carbon atom caused by the isocyanurate ring at 149 ppm. The isocyanurate ring concentration per milligram of polyimide resin (A) is determined. The concentration of the imide ring can also be similarly determined from the spectral intensity of the carbon atom due to the imide ring at 169 ppm by ¹³ C-NMR analysis.

  (3) Number average molecular weight and weight average molecular weight: The number average molecular weight and weight average molecular weight in terms of polystyrene are determined by gel permeation chromatography (GPC).

  In addition, when the content rate of the linear hydrocarbon structure in a polyimide resin (A) is a polyimide resin manufactured with the manufacturing method which a polyimide resin (A) mentions later, the use mass of the polyol compound (a2) in a synthetic raw material The number average molecular weight of the linear hydrocarbon structure can be determined from the number average molecular weight of the polyol compound (a2).

  In addition, the content and number average molecular weight of the linear hydrocarbon structure in the polyimide resin whose manufacturing method is unknown are obtained by heat-treating the polyimide resin in the usual hydrolysis method, for example, in the presence of an organic amine, to decompose the urethane bond, By separating the linear hydrocarbon structure part from the polyimide resin and utilizing the fact that the linear hydrocarbon structure part is less polar than the imide structure part, the linear hydrocarbon structure is obtained with a low polarity organic solvent such as dichloromethane. It can be obtained by extracting a portion and measuring the amount of extraction and GPC analysis.

  Although the manufacturing method of the said polyimide resin used for the thermosetting resin composition of this invention is not specifically limited, It is a polyol compound which has a polyisocyanate compound (a1) and a linear hydrocarbon structure, Comprising: Linear hydrocarbon structure part The polyanhydric acid anhydride having three or more carboxyl groups is converted to a prepolymer (A1) having an isocyanate group at the terminal obtained by reacting with a polyol compound (a2) having a number average molecular weight of 700 to 4,500. A method of reacting the product (b) with an organic solvent is preferred.

  For example, in order to produce a polyimide resin (A) by the above production method, a polyisocyanate having an isocyanurate ring derived from a diisocyanate having a cyclic aliphatic structure having 6 to 13 carbon atoms, and a linear hydrocarbon A prepolymer having an isocyanate group at the terminal obtained by reacting a polyol compound having a structure with a polyol compound having a linear hydrocarbon structure portion having a number average molecular weight of 700 to 4,500 is converted to an acid anhydride of a tricarboxylic acid. The product may be reacted in an organic solvent.

  The polyisocyanate compound (a1) used in the production method is a compound having two or more isocyanate groups in the molecule, and examples thereof include aromatic polyisocyanates and aliphatic polyisocyanates (including cyclic aliphatic polyisocyanates); These polyisocyanate nurate bodies, burette bodies, adduct bodies, allophanate bodies and the like can be mentioned.

  Examples of the aromatic polyisocyanate compound include p-phenylene diisocyanate, m-phenylene diisocyanate, p-xylene diisocyanate, m-xylene diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 4,4. '-Diphenylmethane diisocyanate, polymethylene polyphenyl polyisocyanate (crude MDI), polymethylene polyphenyl isocyanate, 3,3'-dimethyldiphenyl-4,4'-diisocyanate, 3,3'-diethyldiphenyl-4,4'- Diisocyanate, m-xylene diisocyanate, p-xylene diisocyanate, 1,3-bis (α, α-dimethylisocyanatomethyl) benzene, tetramethylxylylene diisocyanate, di Eniren'eteru-4,4'-diisocyanate, naphthalene diisocyanate, and the like.

  Examples of the aliphatic polyisocyanate compound include hexamethylene diisocyanate (HDI), lysine diisocyanate, trimethylhexamethylenemethylene diisocyanate, isophorone diisocyanate (IPDI), 4,4′-dicyclohexylmethane diisocyanate, hydrogenated xylene diisocyanate (HXDI), Examples include norbornylene diisocyanate (NBDI).

  As the polyisocyanate compound (a1), a polyimide resin having good solubility in an organic solvent, compatibility with an epoxy resin or an organic solvent, and a low dielectric constant and dielectric loss tangent of a cured product can be obtained. Group polyisocyanates are preferred. Further, isocyanurate type polyisocyanate is preferable because a cured product having a cured product having good heat resistance can be obtained.

  Furthermore, the polyisocyanate compound (a1) is a polyimide having good solubility in organic solvents, good compatibility with epoxy resins and organic solvents, low dielectric constant and dielectric loss tangent of cured products, and good heat resistance. Since the resin is obtained, the polyisocyanate compound (a11) having an isocyanurate ring derived from an aliphatic polyisocyanate is more preferable, and the polyisocyanate compound having an isocyanurate ring derived from a cyclic aliphatic polyisocyanate is further included. preferable. Examples of the polyisocyanate compound having an isocyanurate ring derived from the cycloaliphatic polyisocyanate include those having a cyclic aliphatic structure of 2 to 3 moles per mole of the isocyanurate ring. What has a cycloaliphatic structure 2.5-3 mol times is more preferable.

  As the polyisocyanate compound (a11), for example, one or two or more aliphatic diisocyanate compounds are isocyanurated in the presence or absence of an isocyanuration catalyst such as a quaternary ammonium salt. And those composed of a mixture of isocyanurates such as trimer, pentamer, and heptamer. Specific examples of the polyisocyanate compound (a11) include isophorone diisocyanate isocyanurate type polyisocyanate (IPDI3N), hexamethylene diisocyanate isocyanurate type polyisocyanate (HDI3N), hydrogenated xylene diisocyanate isocyanurate type polyisocyanate (HXDI3N). ), Isocyanurate type polyisocyanate of norbornane diisocyanate (NBDI3N), and the like.

  The polyisocyanate compound (a11) is a trimeric isocyanurate in 100 parts by mass of the polyisocyanate compound (a1) because a polyimide resin having good solubility in organic solvents and heat resistance of a cured product can be obtained. Is preferably 30 parts by mass or more, particularly preferably 50 parts by mass or more.

  Moreover, as said polyisocyanate compound (a11), since the content rate of an isocyanate group is 10-30 mass%, since the solubility to an organic solvent and the heat resistance of hardened | cured material are favorable, the polyimide resin is obtained. More preferred. Accordingly, the polyisocyanate compound (a11) is most preferably a polyisocyanate compound having an isocyanurate ring derived from a cycloaliphatic polyisocyanate having an isocyanate group content of 10 to 30% by mass. preferable.

  The polyisocyanate having an isocyanurate ring may be used in combination with other polyisocyanates, but isocyanurate type polyisocyanates are preferably used alone.

  The polyol compound (a2) used in the production method has good solubility in an organic solvent, compatibility with an epoxy resin and an organic solvent, a low dielectric constant and dielectric loss tangent of a cured product, and a high glass transition point Tg. A polyol compound having a linear hydrocarbon structure portion having a number average molecular weight of 700 to 4,500 is preferred, and a linear hydrocarbon structure portion having a number average molecular weight of 800 to 4 is obtained because a polyimide resin having excellent film-forming properties can be obtained. , 200 polyol compounds are particularly preferred. A polyol compound having a linear hydrocarbon structure portion with a number average molecular weight of less than 700 is not preferable because the cured product has a high dielectric constant and dielectric loss tangent, while the linear hydrocarbon structure portion has a number average molecular weight of 4,500. A polyol compound exceeding the above is not preferable because the solubility in an organic solvent, the compatibility with an epoxy resin or an organic solvent, and the mechanical properties are poor.

  Examples of the polyol compound (a2) include compounds having an average of 1.5 or more hydroxyl groups bonded to the terminal and / or side chain of the linear hydrocarbon structure in total per molecule. The linear hydrocarbon structure may be linear or branched. The linear hydrocarbon structure may be a saturated hydrocarbon chain or an unsaturated hydrocarbon chain, but a saturated hydrocarbon chain is more preferable from the viewpoint of changes in physical properties and stability during heating.

  The polyol compound (a2) is a polyol compound having a polyolefin structure or a polydiene structure, and a polyol compound having a polyolefin structure or a polydiene structure having a number average molecular weight of 700 to 4,500 and a hydrogenated product thereof. Is mentioned. Examples of the olefin include ethylene, propylene, butene, isobutylene, pentene, and methylpentene. Examples of the diene include pentadiene, hexadiene, isoprene, butadiene, propadiene, and dimethylbutadiene.

  Specific examples of the polyol compound (a2) include polyethylene polyol, polypropylene polyol, polybutadiene polyol, hydrogenated polybutadiene polyol, polyisoprene polyol, hydrogenated polyisoprene polyol, etc., and the number of linear hydrocarbon structure portions. Examples include polyol compounds having an average molecular weight of 700 to 4,500. These may be used alone or in combination of two or more.

  The number of hydroxyl groups in the polyol compound (a2) is preferably 1.5 to 3 on average because it is difficult to gel, a molecular growth is good, and a polyimide resin having excellent flexibility is obtained. Further, the number of hydroxyl groups is particularly preferably an average of 1.8 to 2.2.

  As a commercial item of the said polyol compound (a2), liquid polybutadiene which has a hydroxyl group in both ends, such as NISSO PB (G series) by Nippon Soda Co., Ltd., Poly-bd by Idemitsu Petrochemical Co., Ltd .; Hydrogenated polybutadiene having hydroxyl groups at both ends, such as NISSO PB (GI series) manufactured by Nippon Soda Co., Ltd., polytail H manufactured by Mitsubishi Chemical Corporation, polytail HA, etc .; Poly-iP manufactured by Idemitsu Petrochemical Co., Ltd. Liquid C5 polymer having hydroxyl groups at both ends; hydrogenation having hydroxyl groups at both ends, such as Epol from Idemitsu Petrochemical Co., Ltd., TH-1, TH-2, TH-3 from Kuraray Co., Ltd. Examples include polyisoprene.

  Furthermore, as the polyol compound (a2), ester-modified polyol compounds and urethane-modified polyol compounds obtained by reacting various polybasic acids and polyisocyanates with polyol compounds having a linear hydrocarbon structure as described above can also be used. It is.

  The polyol compound (a2) is preferably a polybutadiene polyol and / or a hydrogenated polybutadiene polyol, and more preferably a hydrogenated polybutadiene polyol.

  In the polyimide resin obtained by the production method, the linear hydrocarbon structure derived from the polyol compound (2a) is introduced between rigid skeletons having imide bonds. In order for the polyimide resin obtained by the manufacturing method to have particularly excellent heat resistance, the glass transition point needs to be high, and therefore the polyol compound (a2) used as a raw material also has a high glass transition point. As a result of intensive studies, the glass transition point of the cured product has a lower glass transition point of the polyol compound (a2) introduced into the molecule of the polyimide resin. It became clear that the hardened | cured material which is more excellent in a mechanical physical property can be obtained by using a polyol compound with a high point and a low glass transition point. From the above knowledge, the glass transition point of the polyol compound (a2) is preferably −120 to 0 ° C.

  In the above production method, the polyol compound (a2) may be used in combination with another hydroxyl group-containing compound to the extent that the effects of the present invention are not impaired. In this case, the other hydroxyl group-containing compound is desirably used at 50% by mass or less based on the total hydroxyl group-containing compound.

  Examples of the acid anhydride (b) of a polycarboxylic acid having three or more carboxyl groups used in the present invention include tricarboxylic acid anhydrides and tetracarboxylic acid anhydrides.

Examples of the acid anhydride of tricarboxylic acid include trimellitic anhydride and naphthalene-1,2,4-tricarboxylic acid anhydride.
Examples of the acid anhydride of tetracarboxylic acid include pyromellitic dianhydride, benzophenone-3,4,3 ′, 4′-tetracarboxylic dianhydride, diphenyl ether-3,4,3 ′, 4′-. Tetracarboxylic dianhydride, benzene-1,2,3,4-tetracarboxylic dianhydride, biphenyl-3,4,3 ', 4'-tetracarboxylic dianhydride, biphenyl-2,3,2 ', 3'-tetracarboxylic dianhydride, naphthalene-2,3,6,7-tetracarboxylic dianhydride, naphthalene-1,2,4,5-tetracarboxylic dianhydride, naphthalene-1, 8,4,5-tetracarboxylic dianhydride, decahydronaphthalene-1,8,4,5-tetracarboxylic dianhydride, 4,8-dimethyl-1,2,3,5,6,7- Hexahydronaphthalene-1,2,5 6-tetracarboxylic dianhydride, 2,6-dichloronaphthalene-1,8,4,5-tetracarboxylic dianhydride, 2,7-dichloronaphthalene-1,8,4,5-tetracarboxylic acid Anhydride, 2,3,6,7-tetrachloronaphthalene-1,8,4,5-tetracarboxylic dianhydride, phenanthrene-1,2,9,10-tetracarboxylic dianhydride, berylene-3 , 4,9,10-tetracarboxylic dianhydride, bis (2,3-dicarboxyphenyl) methane dianhydride, bis (3,4-dicarboxyphenyl) methane dianhydride, 1,1-bis ( 2,3-dicarboxyphenyl) ethane dianhydride, 1,1-bis (3,4-dicarboxyphenyl) ethane dianhydride, 2,2-bis (2,3-dicarboxyphenyl) propane dianhydride 2,3-bis 3,4-dicarboxyphenyl) propane dianhydride, bis (3,4-dicarboxyphenyl) sulfone dianhydride, bis (3,4-dicarboxyphenyl) ether dianhydride And tetracarboxylic anhydride having a group. One or more of these can be used. Further, a tricarboxylic acid anhydride and a tetracarboxylic acid anhydride may be mixed and used.

  The acid value of the polyimide resin obtained by the above production method is preferably 20 to 150 mgKOH / g, more preferably 20 to 120 mgKOH / g in terms of solid matter, in order to improve the solubility in organic solvents and the cured product properties. . When the acid value of the polyimide resin is less than 20 mgKOH / g, the crosslinking density is low and the solder heat resistance is inferior. On the other hand, when the acid value is larger than 150 mgKOH / g, the softening temperature and fluidity of the resin become too high, the followability to the inner layer circuit is deteriorated, and the molding is poor, which is not preferable. The molecular weight of the polyimide resin is preferably a number average molecular weight of 2,000 to 30,000 and a weight average molecular weight of 3,000 to 100,000 in order to improve solvent solubility. More preferably, the number average molecular weight is 2,000 to 10,000 and the weight average molecular weight is 3,000 to 50,000.

  The organic solvent used in the method for producing the polyimide resin may be reacted after it has been present in the system in advance, or it may be introduced in the middle. The prepolymer (a1) having a group and a polycarboxylic acid anhydride (b) having 3 or more carboxyl groups are preferably present at the start of the reaction. In order to maintain an appropriate reaction rate during this reaction, the proportion of the organic solvent in the system is preferably 80% by mass or less, more preferably 10 to 70% by mass of the reaction system. As the organic solvent, since a compound containing an isocyanate group is used as a raw material component, an aprotic polar solvent having no active proton such as a hydroxyl group or an amino group is preferable.

  Next, among the essential components of the thermosetting resin composition of the present invention, the epoxy resin (B) is necessary for obtaining various physical properties such as sufficient heat resistance, chemical resistance and electrical properties as an interlayer insulating material. It is.

  As the epoxy resin (B), bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, phenol novolac type epoxy resin, alkylphenol novolac type epoxy resin, biphenol type epoxy resin, naphthalene type epoxy resin, dicyclo Pentadiene type epoxy resins, epoxidized products of condensates of phenols and aromatic aldehydes having phenolic hydroxyl groups, or bromine atom-containing epoxy resins, phosphorus atom-containing epoxy resins, triglycidyl isocyanurate, alicyclic epoxy resins, etc. Well-known and conventional ones can be used alone or in combination of two or more. Moreover, you may contain the monofunctional epoxy resin as a reactive diluent.

  In particular, in the thermosetting resin composition of the present invention, it is preferable to arbitrarily mix an epoxy resin having an epoxy equivalent of 200 or more and an epoxy resin having an epoxy equivalent of 200 or less. An epoxy resin having an epoxy equivalent of 200 or more has little cure shrinkage, and gives warpage prevention of the base material and flexibility of the cured product. In addition, the melt viscosity at the time of heating lamination and leveling can be increased, which is effective in controlling the amount of resin oozing after molding. On the other hand, an epoxy resin having an epoxy equivalent of 200 or less has high reactivity and gives mechanical strength to the cured product. Moreover, since the melt viscosity at the time of heat lamination is low, it contributes to the filling property of the resin composition into the gaps between the inner layer circuits and the followability to the rough surface of the copper foil.

The organic solvent (C) having a boiling point of 100 ° C. or higher, which is another essential component of the thermosetting resin composition of the present invention, includes ketones such as cyclohexanone, methyl cellosolve, methyl carbitol, triethylene glycol monoethyl ether. Such as glycol ethers, and esters such as acetates of the above glycol ethers, alcohols such as ethylene glycol and propylene glycol, aliphatic hydrocarbons such as octane, petroleum solvents such as petroleum naphtha and solvent naphtha, etc. is there. These can be used alone or in admixture of two or more.
In particular, in the thermosetting resin composition of the present invention, it is important to use an organic solvent having a boiling point of 100 ° C. or higher. The reason for this is that if an organic solvent having a boiling point of less than 100 ° C. is used, the solvent rapidly evaporates when the coating film is dried, resulting in generation of bubbles. Moreover, the solvent is liable to volatilize during application, and the viscosity during application changes abruptly.

  Particularly preferred organic solvents are derivatives of ethylene glycol or propylene glycol, specifically ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol monomethyl, monoethyl, monobutyl, etc. glycol ethers And the acetate compounds thereof. These organic solvents have been conventionally used in large quantities as diluent solvents such as solder resists in printed wiring board manufacturing factories, and are suitable for solvent recovery and reuse in factories, and are also preferred from the standpoint of odor.

The thermosetting resin composition of the present invention further contains an epoxy resin curing agent. The epoxy resin curing agent may be used in combination Lee imidazole compound alone, or two or more kinds.

Among et epoxy resin curing agent, an imidazole compound, a moderate temperature range (80 ℃ ~130 ℃) the reaction time of drying the solvent in the composition, the temperature range during curing (150 ℃ ~200 ℃) This is preferable in that the reaction can sufficiently proceed and the physical properties of the cured product are fully expressed. Moreover, an imidazole compound is preferable also at the point which is excellent in adhesiveness with a copper circuit and copper foil. Particularly preferable examples include 2-ethyl-4-methylimidazole, 2-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, and bis (2-ethyl-4-methyl-imidazole). 2-phenyl-4-methyl-5-hydroxymethylimidazole, 2-phenyl-4,5-dihydroxymethylimidazole, or triazine addition type imidazole.

  These epoxy resin curing agents are preferably blended in the range of 0.05 to 20 parts by mass with respect to 100 parts by mass of the total amount of the epoxy resin (B). If the blending amount is less than 0.05 parts by mass, curing will be insufficient. On the other hand, if the blending amount exceeds 20 parts by mass, the effect of promoting the curing will not be increased, but there will be a problem that the heat resistance and mechanical strength are impaired.

  The thermosetting resin composition of the present invention can be blended with a compound (D) having two or more phenolic hydroxyl groups for the purpose of further improving the mechanical strength and heat resistance of the cured product.

  Examples of the compound (D) having two or more phenolic hydroxyl groups include phenol novolac resin, alkylphenol volac resin, bisphenol A novolac resin, dicyclopentadiene type phenol resin, Xylok type phenol resin, terpene modified phenol resin, polyvinylphenols, etc. A well-known and usual phenol resin can be used individually or in combination of 2 or more types.

  The phenol resin is desirably blended at a ratio of 0 to 1.2 equivalents of the phenolic hydroxyl group with respect to 1 epoxy equivalent of the epoxy resin (B). Outside this range, the heat resistance of the resulting thermosetting resin composition is impaired, which is not preferable.

  The thermosetting resin composition of the present invention can further contain a thermoplastic resin as necessary. As thermoplastic resins, polyesters, polyamides, polyethers, polyimides, polysulfides, polysulfones, polyacetals, butyral resins, NBR, phenoxy resins, polybutadienes, various engineering plastics, etc. can be used alone or in combination of two or more. Can be used.

  These thermoplastic resins may be uniformly dispersed or dissolved in the resin composition at room temperature regardless of whether the epoxy resin in the resin composition is cured and then uniformly dispersed or phase-separated. preferable. These thermoplastic resins contribute to the prevention of repelling during coating and the improvement of transferability, and are effective in increasing the thickness of the coating. Effective for preventing warping. Furthermore, the melt viscosity at the time of heat lamination and leveling can be increased, which is effective in controlling the amount of resin oozing after molding.

  The thermoplastic resin is preferably blended at a ratio of 50% or less of the total composition. If the amount exceeds 50%, the melt viscosity of the coating film may become too high during heating lamination or leveling, or separation may occur in the composition state.

  The thermosetting resin composition of the present invention can be blended with an inorganic filler for the purpose of further improving properties such as adhesion of the cured product, mechanical strength, and linear expansion coefficient. For example, known and commonly used inorganic fillers such as barium sulfate, barium titanate, silicon oxide powder, finely divided silicon oxide, silica, talc, clay, magnesium carbonate, calcium carbonate, aluminum oxide, aluminum hydroxide, mica powder alone Or it can be used in combination. And the blending ratio is suitably 0 to 90% by mass of the resin composition. The particle size of the inorganic filler used here is desirably 95% or more of particles of 3 μm or less, more preferably 2 μm or less, and spherical silica is most suitable.

  Here, the effects of the addition of these inorganic fillers will be described. As a result of the study by the present inventors, it has been clarified that these inorganic fillers are an auxiliary agent for forming irregularities on the surface during desmearing. That is, when the cured coating film of the thermosetting resin composition of the present invention is roughened with a desmear liquid, not only the resin but also these inorganic fillers are simultaneously roughened and act as an anchor effect for the conductor plating layer. This is considered because these inorganic filler particles fall off from the coating film by desmear treatment. Therefore, the particle size of these inorganic fillers is important, and if there are many particles with a particle size of 3 μm or more, there will be a large hole in the roughening profile, which may cause the plating to be unattached or hinder circuit formation. It turned out that it was not preferable. In addition, silica with a low dielectric constant is preferable from the viewpoint of the component, and the spherical type is easier to drop off from the coating film than the crushed type, or the roughened surface has a stable shape, so the anchor effect is greater. It is preferable because the peel strength is increased.

  In addition, the thermosetting resin composition of the present invention may be a known and commonly used phthalocyanine blue, phthalocyanine green, iodin green, disazo yellow, crystal violet, titanium oxide, carbon black, naphthalene black or the like, if necessary. Colorants, asbestos, olben, benton, finely-known silica thickeners, silicone-based, fluorine-based, polymer-based antifoaming agents and / or leveling agents, thiazole-based, triazole-based, silane couplings Adhesiveness-imparting agents such as agents, titanate-based and aluminum-based known conventional additives can be blended.

  The adhesive film for an interlayer insulating material of the multilayer printed wiring board of the present invention is a solid-state solid at room temperature by drying a solvent by heating and / or hot air spraying after applying a resin varnish dissolved in a predetermined organic solvent using a base film as a support. The resin composition can be formed into a film. At this time, the resin coating film of the present adhesive film is preferably adjusted so that the gel time at 150 ° C. is 20 seconds or longer in the semi-cured state. If the gel time in the semi-cured state is 19 seconds or less or does not exist, the resin does not follow the inner layer circuit and voids are likely to occur.

  Examples of the supporting base film include polyolefins such as polyethylene and polypropylene, polyesters such as polyethylene terephthalate, polycarbonates, and silicon films. Particularly preferred is polyethylene terephthalate which is free from defects such as crushing, has excellent dimensional accuracy, and is excellent in cost. As thickness of a support base film, 10-50 micrometers is preferable. When the thickness is less than 10 μm, there is no strength as a support and there is a problem in handling. On the other hand, when the thickness exceeds 50 μm, uneven heat conduction occurs during lamination, resulting in poor lamination. The support base film may be subjected to a release treatment in addition to the mud treatment and the corona treatment.

  Examples of organic solvents include ordinary solvents such as ketones such as acetone, methyl ethyl ketone, and cyclohexanone, acetates such as ethyl acetate, butyl acetate, cellosolve acetate, propylene glycol monomethyl ether acetate, and carbitol acetate, and cellosolves such as cellosolve and butylcellosolve. , Carbitols such as carbitol and butyl carbitol, aromatic hydrocarbons such as toluene and xylene, dimethylformamide, dimethylacetamide, N-methylpyrrolidone, etc., alone or in combination of two or more. Can do. In the adhesive film of the present invention, even if there is a residual organic solvent (specified by the weight reduction rate before and after drying when dried in a dryer maintained at 150 ° C. for 30 minutes) There is no problem as long as the characteristics as a printed circuit board such as generation of voids are not impaired after curing. Generally, it is 10 mass% or less.

  The thickness of the film formed as described above is equal to or greater than the conductor thickness of the inner layer circuit board to be laminated, and the remaining copper ratio, plate thickness, through hole diameter, surface via hole diameter, number of holes and insulation of the inner layer circuit pattern are insulated. Although it differs depending on the set value of the layer thickness, it is generally in the range of 10 to 120 μm. When the plate is thick and the resin filling volume of the through hole is large, a thicker film is required. The adhesive film of the present invention consisting of a film composed of a normal temperature solid resin composition and a support base film thus obtained is laminated as it is or with a protective film further laminated on the other surface of the film, and wound into a roll. Stored. Examples of the protective film include polyolefins such as polyethylene and polypropylene, polyesters such as polyethylene terephthalate, and the like. From the viewpoint of cost, a polyolefin film is preferable, and polypropylene with less crushing and chipping is particularly preferable. Moreover, as thickness of a protective film, 5-50 micrometers is common. In addition, the protective film may be subjected to a mold release process in addition to the mud process and the embossing process.

  Examples of the synthesis of imide resins used in the present invention, examples using them, comparative examples and test examples will be described in detail below, but the present invention is not limited to the following examples. Of course. In the following, “parts” and “%” are based on mass unless otherwise specified.

Synthesis example 1
In a 20-liter flask equipped with a stirrer, a thermometer, and a condenser, 4951 parts of diethylene glycol monoethyl ether acetate (hereinafter abbreviated as EDGA) and a polyisocyanate having an isocyanurate ring derived from isophorone diisocyanate (hereinafter referred to as EDGA) IPDI-N is abbreviated as IPDI-N, has an isocyanate group content of 18.2%, an isocyanurate ring-containing triisocyanate content of 85%, 2760 parts (12 moles as an isocyanate group), and polytail HA (both ends manufactured by Mitsubishi Chemical Corporation). Was charged with hydrogenated liquid polybutadiene having a hydroxyl group, number average molecular weight 2,100, hydroxyl value 51.2 mgKOH / g] 2191 parts (2 moles as a hydroxyl group), and heated to 80 ° C. while taking care of heat generation while stirring. After 3 hours reaction Subsequently, 1536 parts of EDGA and 1536 parts (8 mol) of trimellitic anhydride (hereinafter abbreviated as TMA) were charged, and the temperature was raised to 160 ° C., followed by reaction for 4 hours. The reaction proceeded with foaming. The system became a light brown clear liquid, and a polyimide resin solution was obtained.

The obtained polyimide resin solution was coated on a KBr plate and the infrared absorption spectrum of the sample in which the solvent was volatilized was measured. As a result, 2270 cm ^−1, which is the characteristic absorption of the isocyanate group, disappeared completely, and 725 cm ⁻¹ and 1780 cm ⁻ absorption of the imide ring ¹ and 1720 cm ^-1, characteristic absorption of isocyanurate ring at 1690 cm ^-1 and 1460 cm ^-1, characteristic absorption of the urethane bond at 1550 cm ^-1. The acid value of the polyimide resin is 79 mgKOH / g in terms of solid content, the concentration of the isocyanurate ring is 0.66 mmol / g (in terms of resin solid content), and the number average molecular weight (hereinafter abbreviated as Mn) is 5. The weight average molecular weight (hereinafter abbreviated as Mw) was 24,000. Hereinafter, this polyimide resin solution is abbreviated as (X-1).

Synthesis example 2
Polyisocyanate having an isocyanurate ring derived from 1,6-hexanediisocyanate in 4300 parts of EDGA, 2070 parts of IPDI-N (9 mol as isocyanate group), in a 20-liter flask equipped with a stirrer, a thermometer and a condenser (Isocyanate group content 22.9%, isocyanurate ring-containing triisocyanate content 63.3%) 550 parts (3 moles as isocyanate groups) were charged and mixed to make uniform, then 2191 parts of polytail HA (as hydroxyl groups) 2 mol) was added and the temperature was raised to 80 ° C. while paying attention to heat generation while stirring, and the reaction was carried out for 3 hours. Next, 1536 parts (8 mol) of TMA was charged, and the temperature was raised to 160 ° C., followed by reaction for 4 hours. The reaction at this time proceeded with foaming, and when the viscosity increased and the system became difficult to stir, 2000 parts of EDGA was further added. The system became a light brown clear liquid, and a polyimide resin solution was obtained.

As a result of measuring an infrared absorption spectrum in the same manner as in Synthesis Example 1 using the obtained polyimide resin solution, 2270 cm ^−1, which is the characteristic absorption of the isocyanate group, disappeared completely, and 725 cm ⁻¹ , 1780 cm ⁻¹ and 1720 cm ^−1. absorption of an imide ring, characteristic absorption of isocyanurate ring at 1690 cm ^-1 and 1460 cm ^-1, characteristic absorption of the urethane bond to 1550 cm ^-1 was confirmed on. Furthermore, the acid value of the polyimide resin was 85 mgKOH / g in terms of solid content, the concentration of the isocyanurate ring was 0.68 mmol / g, Mn was 5,500, and Mw was 22,000. Hereinafter, this polyimide resin solution is abbreviated as (X-2).

Synthesis example 3
Polyisocyanate having an isocyanurate ring derived from norbornylene diisocyanate in 5310 parts of EDGA, 1380 parts of IPDI-N (6 mol as isocyanate group), in a 20-liter flask equipped with a stirrer, a thermometer and a condenser (Isocyanate group content: 18.75%, isocyanurate ring-containing triisocyanate content: 65.5%) 1344 parts (6 moles as isocyanate groups) were charged and dissolved by heating at 80 ° C., and polytail HA 2191 parts (hydroxyl groups 2 moles) Was added, and the reaction was carried out at 80 ° C. for 5 hours while stirring. Then, 1536 parts (8 mol) of TMA was added, and the temperature was raised to 170 ° C., followed by reaction for 4 hours. The reaction proceeded with foaming. The inside of the system became a light brown clear liquid, and a polyimide resin solution was obtained.

As a result of measuring an infrared absorption spectrum in the same manner as in Synthesis Example 1 using the obtained polyimide resin solution, 2270 cm ^−1, which is the characteristic absorption of the isocyanate group, disappeared completely, and 725 cm ⁻¹ , 1780 cm ⁻¹ and 1720 cm ^−1. absorption of an imide ring, characteristic absorption of isocyanurate ring at 1690 cm ^-1 and 1460 cm ^-1, characteristic absorption of the urethane bond to 1550 cm ^-1 was confirmed on. The acid value of the polyimide resin was 75 mgKOH / g in terms of solid content, the concentration of the isocyanurate ring was 0.72 mmol / g, Mn was 4,400, and Mw was 21,000. Hereinafter, this polyimide resin solution is abbreviated as (X-3).

Examples 1 to 8 and Comparative Examples 1 and 2
To the blending components shown in Table 1, propylene glycol monomethyl ether acetate as an organic solvent and Aerosil # 972, which is fine silica, are added and kneaded and dispersed in a three-roll mill, and the viscosity is 40 dPa · s ± 10 dPa · s (rotation) A thermosetting resin composition adjusted to a viscometer of 5 rpm at 25 ° C. was obtained. The thixotropic index (TI value) of the obtained thermosetting resin composition was all in the range of 1.2 to 2.0.

Examples 9 to 18 and Comparative Examples 3 and 4
The thermosetting resin compositions obtained in Examples 1 to 8 and Comparative Examples 1 and 2 (however, instead of 2PHZ (2-phenylhydroxyethylimidazole, manufactured by Shikoku Kasei Kogyo Co.), 1B2PZ (1-benzyl- 2-phenylimidazole (manufactured by Shikoku Kasei Kogyo Co., Ltd.)) was applied to a PET film (Toray Co., Ltd., Lumirror 38R75: 38 μm) using a roll coater so that the film thickness was 50 μm. And dried at 40 to 120 ° C. to obtain an adhesive film. At this time, the gelation time at 150 ° C. was in the range of 20 to 120 seconds for all samples.

Test example 1
The thermosetting resin compositions obtained in Examples 1 to 8 and Comparative Examples 1 and 2 were each screen-printed on copper foil (35 μm), dried at 110 ° C. for 30 minutes, and then 150 ° C. × 30 minutes. Final curing was performed at 170 ° C. for 30 minutes. The copper foil of this sample was etched, and the physical properties of each cured film were measured. The results are shown in Table 2.

Test example 2
Each of the thermosetting resin compositions obtained in Examples 1 to 8 and Comparative Examples 1 and 2 was used with a vertical lifting roll coater (manufactured by Furnace) provided with a urethane rubber roll having a groove pitch of 1000 μm. Then, an inner layer circuit is formed from a glass epoxy double-sided copper-clad laminate having a thickness of 18 μm and is simultaneously applied to both sides of a substrate that has been subjected to an etch bond (manufactured by MEC), and then dried at 110 ° C. to form an insulating layer A dry coating was formed.

Next, according to the first embodiment of the printed wiring board manufacturing method described above, the dried substrate is finally cured in a hot air circulation drying furnace at 150 ° C. for 30 minutes, and a CO ₂ laser (manufactured by Mitsubishi Electric Corporation) is used. The hole was drilled. Next, desmear treatment, electroless copper plating, and electrolytic copper plating were performed using a general-purpose chemical, and a circuit was formed by a panel plating method to obtain a printed wiring board. The obtained printed wiring board was heat-treated at 170 ° C. for 30 minutes for the purpose of removing moisture and annealing copper plating.

  The following physical properties and characteristics of the printed wiring board thus produced were evaluated. The results are shown in Table 3.

上記表２及び表３中の各物性及び特性は、以下のようにして測定・評価した。

The physical properties and characteristics shown in Tables 2 and 3 were measured and evaluated as follows.

(A) Glass transition temperature Tg:
It was measured by TMA (thermomechanical analysis).

(B) CTEα1 (linear expansion coefficient equal to or less than Tg):
Measured by TMA.

(C) Dielectric constant Dk and dielectric loss tangent Df:
It measured according to JIS K6911.

(D) Water absorption rate The cured film was immersed in distilled water controlled at 23 ° C. ± 2 ° C., and obtained from the mass change after 24 hours.

(E) Peel strength:
It measured according to JIS C6481.

(F) Solder heat resistance:
The completed printed wiring board (10 cm × 10 cm) is immersed in a solder layer at 288 ° C. ± 3 ° C. for 10 seconds. After repeating this operation five times, peeling of the copper foil and the resin was confirmed. In addition, the meaning of the code | symbol in Table 3 is as follows.
OK: no peeling NG: peeling

(G) Pattern formability:
Line and space The peeling of the 75 μm / 75 μm circuit was visually inspected. In addition, the meaning of the code | symbol in Table 3 is as follows.
OK: no peeling NG: peeling

(H) Flame retardancy:
An insulating layer was formed on both sides of a 0.4 mm thick FR-4 base material with a cured coating film to a thickness of 80 μm, and the test was conducted according to UL-94. In addition, the meaning of the code | symbol in Table 3 is as follows.
NG: The flame of the sample piece reaches the clamp, and is UL-94 V0 non-conformity.

Test example 3
In the production of the substrates of Examples 1 to 8, the characteristics of the substrates produced in the same manner except that the buff polishing equivalent to # 320 and # 600 was repeated twice after post-curing, and the unevenness of the inner layer circuit was further similar to the above. It was confirmed that the unevenness of the substrate surface due to the decrease.

Test example 4
The characteristics of the substrate produced by changing the panel plating method to the semi-additive method in the production of the substrates of Examples 1 to 8 are almost the same as described above, and a circuit of line / space = 25 μm / 25 μm can be formed and peeling occurs. It wasn't.

Test Example 5
Next, according to the second embodiment of the method for producing a printed wiring board described above, the substrate on which the dried coating film of the thermosetting resin composition of Examples 1, 2, 5 to 8 and Comparative Examples 1 and 2 was formed. 18 μm thick copper foil (manufactured by Japan Energy Co., Ltd.) is layered on both sides, and using a vacuum laminator (MEIKI, MVLP-500), heat lamination is performed under the conditions of 5 kgf / cm ² , 150 ° C., 1 minute, 1 Torr, Next, after leveling with a hot plate press at 10 kgf / cm ² and 150 ° C. for 1 minute, the plate was cured with a hot air circulating dryer at 170 ° C. for 30 minutes to produce a laminate.

  Furthermore, a predetermined through-hole part of this laminated board is drilled with a drill, and the laser via part is first provided with a guide by selectively removing the copper foil using an etching resist at the hole position, and using a laser processing machine. Drilled a hole. Next, after removing the smear of the through-hole part and the laser via part by desmear treatment, the hole is made conductive by electroless copper plating and electrolytic copper plating, and pattern formation is performed by etching through a commercially available etching resist. A plate was made. With respect to the multilayer printed wiring board produced in this manner, the peel strength, solder heat resistance, pattern formability, and flame retardancy were evaluated in the same manner as described above. The results obtained are shown in Table 4 below.

Test Example 6
The adhesive films prepared in Examples 9 to 18 and Comparative Examples 3 and 4 were applied to a 35 μm copper foil using a vacuum laminator (MVLP-500, manufactured by MEIKI) at 5 kgf / cm ² , 140 ° C., 1 minute, 1 Torr. And then leveling under conditions of 10 kgf / cm ² , 150 ° C. and 1 minute with a hot plate press machine, then 150 ° C. × 60 minutes with a hot air circulating dryer and 170 ° C. × 30 minutes. Cured under conditions. And the copper foil of the obtained sample was etched with the commercially available etching liquid, and the physical property was evaluated like the said test example 1. FIG. The results are shown in Table 5.

Test Example 7
Next, according to the first embodiment of the method for producing a printed wiring board described above, the adhesive films prepared in Examples 9 to 18 and Comparative Examples 3 and 4 were formed from a glass epoxy double-sided copper-clad laminate having a copper foil thickness of 18 μm. Using a vacuum laminator (MELPI, MVLP-500) on both sides of the substrate on which the inner layer circuit was formed and further treated with etch bonding (MEC), the conditions were 5 kgf / cm ² , 140 ° C., 1 minute, 1 Torr. After heating and laminating, and leveling with a hot plate press at 10 kgf / cm ² and 150 ° C. for 1 minute, the laminate is cured with a hot air circulation dryer at 150 ° C. for 60 minutes. Produced.

  Further, predetermined through-hole portions, via-hole portions and the like of this laminated plate were drilled with a drill and a laser, and then desmear treatment and surface unevenness formation were performed using a general-purpose chemical. Next, after the entire surface and the hole are made conductive by electroless copper plating and electrolytic copper plating, heat treatment is performed at 170 ° C. for 30 minutes for the purpose of moisture removal and copper plating annealing, and then through a commercially available etching resist. A pattern was formed by etching to produce a multilayer printed wiring board.

  The multilayer printed wiring board thus produced was tested and evaluated for the physical properties and characteristics shown in Table 6 in the same manner as in Test Example 2. The results are shown in Table 6.

Test Example 8
In the production of the substrates of Examples 9 to 18, the characteristics of the substrate produced by changing the panel plating method to the semi-additive method are almost the same as described above, and furthermore, a circuit of line / space = 25 μm / 25 μm can be formed, and peeling occurs. It wasn't.

Test Example 9
Next, according to the first aspect of the method for manufacturing a printed wiring board described above, the support film of the laminated board laminated with the adhesive films prepared in Examples 9 to 11 and 15 to 18 and Comparative Examples 3 and 4 is peeled off. , 18 μm thick copper foil (JTC-AM, manufactured by Japan Energy Co., Ltd.), and laminating using a vacuum laminator (MELPI, MVLP-500) at 5 kgf / cm ² , 150 ° C., 1 minute, 1 Torr. Then, after leveling with a hot plate press at 10 kgf / cm ² and 150 ° C. for 1 minute, the plate was cured with a hot air circulation dryer at 170 ° C. for 30 minutes to produce a laminate.

  Furthermore, a predetermined through hole portion of this laminated board is drilled with a drill, and the laser via portion is first provided with a guide by selectively removing the copper foil using an etching resist at the hole position, and a laser processing machine is used to provide a hole. Dawned. Next, after removing the smear of the through-hole part and the laser via part by desmear treatment, the hole part is made conductive by electroless copper plating and electrolytic copper plating, and a pattern is formed by etching through a commercially available etching resist, A multilayer printed wiring board was produced. With respect to the multilayer printed wiring board produced in this manner, the peel strength, solder heat resistance, pattern formability, and flame retardancy were evaluated in the same manner as described above. The obtained results are shown in Table 7 below.

  The thermosetting resin composition of the present invention and the thermosetting adhesive film produced using the same are multilayer printed wiring boards, in particular, a build-up type multilayer in which conductor circuit layers and insulating resin layers are alternately stacked. This is useful for forming an interlayer insulating resin layer of a printed wiring board.

Claims (5)

On the support base film, (A) a linear hydrocarbon structure having a carboxyl group or an acid anhydride group and having a number average molecular weight of 700 to 4,500, a urethane bond, an imide ring, and an isocyanurate ring (B) epoxy resin, and 2-ethyl-4-methylimidazole, 2-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, bis (2 -Ethyl-4-methyl-imidazole), 2-phenyl-4-methyl-5-hydroxymethylimidazole, 2-phenyl-4,5-dihydroxymethylimidazole, and an imidazole compound selected from the group consisting of triazine-added imidazole. A film made of a thermosetting resin composition contained as an essential component is in a semi-cured state Thermosetting adhesive film, characterized by being made. The polyimide resin (A) has a structural unit represented by the following general formula (1) and a structural unit represented by the following general formula (2), and the following general formulas (3), (4) and (5) The thermosetting adhesive film according to claim 1 , wherein the thermosetting adhesive film is a polyimide resin having any one or more of terminal structures represented by the formula:

The polyimide resin (A) is a polyimide resin having an acid value of 20 to 150 mgKOH / g, and the mass ratio (A) / (B) between the polyimide resin (A) and the epoxy resin (B) is 0.1. The thermosetting adhesive film according to claim 1, wherein the thermosetting adhesive film is 10 or more . The thermosetting adhesive film according to any one of claims 1 to 3 , wherein the thermosetting resin composition further contains a compound (C) having two or more phenolic hydroxyl groups. Multilayer printed circuit board, wherein the thermosetting adhesive film with interlayer insulating resin layer is formed of any one of claims 1 to 4.