JP2005136050A - Wiring board and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a good wiring board including liquid crystal polymer as an insulating layer, which improves reliability in connection of a through conductor and prevents the occurrence of blisters even in a through conductor containing tin or indium. <P>SOLUTION: The wiring board includes one or more liquid crystal polymer insulating layers 1 containing at least liquid crystal polymer, an inner wall hole 2a passing through the insulating layer 1, an inner wall layer 3 provided inside the hole 2a and containing a resin other than the liquid crystal polymer, and the through conductor 4 provided through the inner wall layer 3. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a wiring board suitable for, for example, a wiring board and a package for housing a semiconductor element, and a method for manufacturing the wiring board, and particularly relates to a wiring board using a liquid crystal polymer insulating layer as an insulating layer.

  Conventionally, a wiring board is formed by bonding a metal foil to the surface of an insulating layer containing a resin called a prepreg formed by impregnating an epoxy resin into a glass cloth, and then etching this to form a fine conductor wiring layer. After laminating a plurality of insulating layers on which conductor wiring layers are formed, a through hole is formed at a desired position by a micro drill, and a metal is deposited on the inner wall of the through hole by a plating method to form a through conductor. It is manufactured by electrically connecting the wiring layers.

  In general, current electronic devices are required to be small, thin, lightweight, high performance, high functionality, high quality, and high reliability, as represented by mobile communication devices. Electronic components such as hybrid integrated circuits are also required to be smaller and higher in density, and in order to meet such demands for higher density, the wiring boards that make up electronic components are also used as conductor wiring layers. Therefore, it is necessary to reduce the thickness of the insulating layer, the insulating layer, and the through hole.

  However, in the conventional method of forming a through conductor on the inner wall of the through hole by plating, the through hole penetrates from the upper surface to the lower surface of the wiring board, so the number of through holes increases as the number of stacked layers increases. If it increases, it becomes impossible to secure a space necessary for wiring, and as a result, there is a problem that it is not possible to respond to the demand for more multilayer wiring boards due to light and thin electronic devices.

  In order to solve such problems, a technique has been developed for forming a wiring board by laminating insulating layers after forming through conductors for electrically connecting upper and lower conductive wiring layers for each insulating layer. .

  In such a wiring board, an epoxy resin prepreg is used as an insulating layer in the same manner as a general wiring board, and the through conductor is formed by depositing a metal film on the inner wall of the through hole by a plating method. However, when penetrating conductors are formed by plating, the chemicals used to perform chemical plating are expensive, the process is complicated and the processing time is long, or harmful chemicals are used to the environment. The through conductor is formed by filling the through hole with a conductive paste containing a low-resistance metal powder such as copper, and then an insulating layer is laminated to form a wiring board. Has been proposed (see Patent Documents 1 to 3).

  However, an insulating layer made of an epoxy resin prepreg has a high hygroscopic property of the resin itself, so that the migration resistance is low, and when the wiring density is high, in an insulation reliability test such as HAST or a high temperature and high humidity bias test, There was a problem such as short-circuiting. In addition, epoxy resin has a problem in electrical characteristics in a high frequency region because of its high dielectric constant and dielectric loss tangent.

  In order to solve such problems, it has been studied to use a liquid crystal polymer as a material for an insulating layer of a wiring board. An insulating layer containing a liquid crystal polymer is composed of rigid molecules and has a structure in which the molecules are regularly arranged to some extent, and the intermolecular force is strong, so it has high heat resistance, high elastic modulus, It has high dimensional stability and low hygroscopicity, does not require the use of a reinforcing material such as glass cloth, and is excellent in fine workability. Furthermore, the high frequency region also has the characteristics of low dielectric constant and low dielectric loss tangent and excellent high frequency characteristics.

  Taking advantage of such characteristics of the liquid crystal polymer, a conductive wiring layer made of metal foil is formed on at least one surface of the insulating film formed by forming a coating layer containing a thermosetting resin on the upper and lower surfaces of the liquid crystal polymer insulating layer. A plurality of these are laminated, and the conductive wiring layers positioned above and below the insulating film are electrically connected through a through conductor formed by filling a through hole formed in the insulating film with a conductive material. A wiring board is also proposed (see Patent Document 4).

  In addition, the conductive material that fills the through hole and becomes the through conductor needs to contain a resin for enhancing the filling property to the through hole and bond between the metal particles as an essential component, Thermosetting epoxy resins having a high bonding property have generally been used.

  However, such conduction between the through conductor and the conductor wiring layer is performed by simple contact between the metal powder and the conductor wiring layer, and the bonding strength between the metal powder and the conductor wiring layer is insufficient, and the temperature cycle test is performed. In such a case, the contact is separated and the conduction resistance is increased or the wire is disconnected.

  In addition, since the insulating layer contains a resin, after the through conductor is formed, it is heated to sinter a low-resistance metal such as copper or silver, and the metal powder and the conductor wiring layer are bonded together to bond strength between them. It was also difficult to increase.

In order to solve such problems, a part of metal such as copper and silver, which is a metal generally used as a conductive component in the conductive material of the through conductor, is replaced with a low melting point metal such as indium or tin. A method has been proposed in which silver metal powder is bonded with a low-melting-point metal to improve the connection reliability of the metal particles and the joint portion between the through conductor and the conductor wiring layer (see Patent Document 5).
JP 56-101739 A JP 58-49966 A JP-A-8-138437 JP 2002-261453 A JP 1998-17054 A

  However, when a low melting point metal such as indium or tin is blended in the through conductor, when the conductive material is cured and becomes a through conductor in the portion where the liquid crystal polymer exposed on the inner wall surface of the through hole is in contact with the through conductor In addition, the liquid crystal polymer insulating layer contracts due to a rapid endothermic reaction accompanying melting of a low melting point metal such as indium or tin, and as a result, the through conductor is peeled off from the inner wall of the through hole.

  In addition, when a through conductor not containing indium and tin is used, the above problem can be solved, but the problem of low reliability due to low adhesion between the through conductor and the liquid polymer insulating layer. there were.

  The present invention has been devised in view of the problems of the prior art, and an object thereof is to provide a wiring board excellent in connection reliability and a manufacturing method thereof.

  The wiring board of the present invention contains at least one liquid crystal polymer insulating layer containing at least a liquid crystal polymer, an inner wall hole penetrating the liquid crystal polymer insulating layer, and a resin excluding the liquid crystal polymer provided inside the inner wall hole. An inner wall layer formed through the inner wall layer and a through conductor provided through the inner wall layer.

  Moreover, as for the wiring board of this invention, it is desirable for an inner wall layer to contain a thermosetting resin.

  Moreover, as for the wiring board of this invention, it is desirable for an inner wall layer to contain a thermoplastic resin.

  Moreover, as for the wiring board of this invention, it is desirable for the thickness of an inner wall layer to be 0.1-15 micrometers.

  In the wiring board of the present invention, when the thermal expansion coefficient of the liquid crystal polymer insulating layer is A, the thermal expansion number of the inner wall layer is B, and the thermal expansion coefficient of the through conductor is C, A <B <C. desirable.

  In the wiring board of the present invention, it is desirable that a coating layer containing a resin excluding the liquid crystal polymer is formed on at least one main surface of the liquid crystal polymer insulating layer.

  Moreover, as for the wiring board of this invention, it is desirable for a coating layer to contain a thermosetting resin.

  Moreover, as for the wiring board of this invention, it is desirable for a coating layer to contain a thermoplastic resin.

  Moreover, as for the wiring board of this invention, it is desirable for a coating layer and an inner wall layer to contain the same resin.

  The wiring board of the present invention is a conductive material in which a through conductor contains 6 to 15% by mass of a thermosetting resin, 2.5 to 10% by mass of silver, and 75 to 91.5% by mass of copper. It is desirable that it be formed.

  In the wiring board of the present invention, the through conductor is 6 to 15% by mass of thermosetting resin, 2.5 to 10% by mass of silver, 45 to 86.5% by mass of copper, and 5 to 30% by mass of copper. It is desirable that the conductive material is formed of a conductive material containing tin or indium.

  Further, the method for producing a wiring board of the present invention includes a step of forming an inner wall hole penetrating a predetermined portion of the liquid crystal polymer insulating layer, and a varnish containing a resin excluding the liquid crystal polymer to be the inner wall layer prepared in advance. Filling the inner wall hole and forming an inner wall layer in the inner wall hole; forming a through hole penetrating the inner wall layer formed in the inner wall hole; and filling the through hole with a conductive material. A plurality of liquid crystal polymer insulations comprising a step of forming a through conductor, a step of transferring a conductor wiring layer to the liquid crystal polymer insulating layer, and an inner wall layer, a through conductor and a conductor wiring layer produced by repeating the above steps. And a step of stacking layers to form a multilayer.

  Further, the method for producing a wiring board of the present invention includes a step of forming an inner wall hole penetrating a predetermined portion of the liquid crystal polymer insulating layer, and a varnish containing a resin excluding the liquid crystal polymer to be the inner wall layer prepared in advance. A step of filling the inner wall hole and forming an inner wall layer in the inner wall hole; and a coating layer comprising a resin excluding the liquid crystal polymer on at least one main surface of the liquid crystal polymer insulating layer provided with the inner wall layer. Forming a through hole penetrating the coating layer and the inner wall layer formed in the inner wall hole, filling the through hole with a conductive material to form a through conductor, A step of transferring the conductor wiring layer to the coating layer, and a plurality of liquid crystal polymer insulating layers each including an inner wall layer, a through conductor, a coating layer, and a conductor wiring layer produced by repeating the above steps are laminated to form a multilayer. And comprising a process And it features.

  In addition, the method for manufacturing a wiring board according to the present invention includes a laminate in which a liquid crystal polymer insulating layer having substantially the same thickness and an inner wall layer sheet containing a resin other than the liquid crystal polymer serving as an inner wall layer are laminated. A step of producing, pressing a predetermined portion of the laminate from the inner wall layer sheet side, and moving a pressing portion of the inner wall layer sheet to the liquid crystal polymer insulating layer side, whereby the liquid crystal polymer insulating layer and the inner wall layer sheet A step of forming a composite member integrated with each other, a step of forming a through hole penetrating the inner wall layer of the composite member, a step of filling the through hole with a conductor to form a through conductor, A step of transferring the conductor wiring layer to the main surface of the composite member on which the through conductor is formed to form a conductor wiring layer on the main surface of the composite member; and an inner wall layer, a through conductor and a conductor produced by repeating the above steps. A plurality of wiring layers. Characterized by the steps of multilayer laminated liquid crystal polymer insulating layer, the provided.

  In addition, the method for manufacturing a wiring board according to the present invention includes a laminate in which a liquid crystal polymer insulating layer having substantially the same thickness and an inner wall layer sheet containing a resin other than the liquid crystal polymer serving as an inner wall layer are laminated. A step of producing, pressing a predetermined portion of the laminate from the inner wall layer sheet side, and moving a pressing portion of the inner wall layer sheet to the liquid crystal polymer insulating layer side, whereby the liquid crystal polymer insulating layer and the inner wall layer sheet A composite member integrated with each other, a step of forming a coating layer containing a resin excluding a liquid crystal polymer on at least one main surface of the composite member, and a penetration through the coating layer and the inner wall layer A step of forming a through-hole, a step of filling the through-hole with a conductor to form a through-conductor, and a conductor wiring layer transferred to the main surface of the composite member on which the through-conductor is formed. Conductor wiring on the main surface Forming a, characterized by comprising the steps of multilayer by laminating a plurality of composite members comprising a covering layer and the through conductor and the conductor wiring layer produced by repeating the above steps.

  In addition, the method for manufacturing a wiring board according to the present invention includes a step of forming an inner wall hole penetrating a predetermined portion of the liquid crystal polymer insulating layer, and a resin excluding the liquid crystal polymer to be the inner wall layer and the covering layer prepared in advance. Immersing the liquid crystal polymer insulating layer in which the inner wall hole is formed in a varnish, forming an inner wall layer in the inner wall hole, and forming a coating layer on a surface of the liquid crystal polymer insulating layer in which the inner wall layer is formed; A step of forming a through hole penetrating the inner wall layer formed in the inner wall hole, a step of filling the through hole with a conductor to form a through conductor, and a conductor wiring layer on a main surface of the covering layer A step of transferring, and a step of laminating a plurality of the liquid crystal polymer insulating layers each including a coating layer, an inner wall layer, a through conductor, and a conductor wiring layer produced by repeating the above-described steps. It is characterized by.

  In the wiring board of the present invention, the through conductor and the liquid polymer insulating layer are connected to the inner wall of the through hole instead of the liquid polymer insulating layer having a low adhesive force, and the through conductor and the liquid polymer insulating layer are isolated from each other. By providing an inner wall layer containing a resin other than the liquid crystal polymer, the connection strength between the liquid crystal polymer insulating layer and the through conductor can be increased.

  In addition, even if a substance that would cause a malfunction when in contact with the liquid crystal polymer insulation layer is contained in the through conductor, contact between the through conductor and the liquid crystal polymer insulation layer can be prevented. Can be prevented.

  In addition, the wiring board of the present invention uses a thermosetting resin for the inner wall layer, and by heating the wiring board, the liquid crystal polymer insulating layer and the through conductor are bonded with the thermosetting resin of the inner wall layer. The connection between the layer and the through conductor can be particularly strengthened, and the connection reliability of the through conductor can be improved.

  Also, by using a thermoplastic resin for the inner wall layer, the wiring board is heated to the softening temperature of the thermoplastic resin to melt the inner wall layer, and the liquid crystal polymer insulating layer and the through conductor are melt bonded to each other by the inner wall layer. The connection between the insulating layer and the through conductor can be strengthened, and the connection reliability of the through conductor can be improved.

  By making the thickness of the inner wall layer greater than 0.1 μm, the liquid crystal polymer insulating layer and the through conductor can be firmly connected. Further, since the liquid crystal polymer insulating layer and the through conductor can be isolated from each other, cracks and peeling are less likely to occur between the liquid crystal polymer insulating layer and the through conductor. In addition, for example, when the through conductor composition contains a low melting point metal such as indium or tin, the inner wall layer absorbs the influence even if there is a sudden endothermic reaction accompanying the melting of the low melting point metal, and the liquid crystal polymer insulation Cracks and peeling between the layer and the through conductor can be prevented. In addition, stress due to the difference in thermal expansion coefficient is generated between the liquid crystal polymer insulating layer having a low thermal expansion coefficient and the through conductor having a high thermal expansion coefficient. However, the presence of the inner wall layer can alleviate the stress. it can. Further, by setting the thickness of the inner wall layer to 15 μm or less, the resin of the inner wall layer hardly flows during heating and pressurization such as lamination and curing, and the conductor wiring layer and the through conductor are not deformed. Further, the pitch between the through conductors can be reduced, and a high-density wiring board can be manufactured.

  Further, in the wiring board of the present invention, when the thermal expansion coefficient of the liquid crystal polymer insulating layer is A, the thermal expansion coefficient of the inner wall layer is B, and the thermal expansion coefficient of the through conductor is C, the relationship of A <B <C is satisfied. In such a wiring board, since the thermal expansion coefficient of the inner wall layer is a value between the thermal expansion coefficients of the liquid crystal polymer insulating layer and the through conductor, the inner wall layer is formed between the liquid crystal polymer insulating layer and the through conductor. The difference in thermal expansion coefficient can be alleviated, and cracks between the insulating layer and the through conductor can be prevented.

  Further, by forming a coating layer having an adhesive property containing a resin excluding the liquid crystal polymer on at least one main surface of the liquid crystal polymer insulating layer which can be thermally welded only at a melting point or higher (300 ° C.), the liquid crystal polymer A conductor wiring layer can be easily formed on the main surface of the liquid crystal polymer insulating layer via a coating layer even in a temperature range below the melting point.

  Also, when a thermosetting resin is used for the covering layer, the conductor wiring layer is embedded in the covering layer and the wiring board is heated, so that the conductor wiring layer and the thermosetting resin of the covering layer are bonded. Thus, a wiring board having excellent connection reliability between the conductor wiring layer and the coating layer can be obtained.

  When a thermoplastic resin is used for the coating layer, the conductor wiring layer is embedded in the coating layer, and the wiring board is heated to the softening temperature of the thermoplastic resin, so that the coating layer is melted. By melting and bonding the coating layer and the coating layer, a wiring substrate having excellent connection reliability between the conductor wiring layer and the coating layer can be obtained.

  In addition, since the same resin is used for the coating layer and the inner wall layer, the connection between the coating layer and the inner wall layer is improved, so the occurrence of cracks and migration between the coating layer and the inner wall layer is suppressed, and the reliability of the wiring board Can be improved. Further, by using the same resin for the covering layer and the inner wall layer, it is possible to easily reduce the cost by the same material, simplify the process by the simultaneous formation process, and reduce the cost.

  Moreover, it oxidizes by forming a penetration conductor with the electrically conductive material which contains 6-15 mass% thermosetting resin, 2.5-10 mass% silver, and 75-91.5 mass% copper. Copper that is easy to oxidize can be coated with silver that is difficult to oxidize, and the oxidation of copper is prevented by silver, and the increase in connection resistance due to oxidation such as being left at high temperature is reduced, and the connection reliability of the through conductor can be improved.

  Further, the through conductor is made of 6 to 15% by mass of thermosetting resin, 2.5 to 10% by mass of silver, 45 to 86.5% by mass of copper, and low melting point of 5 to 30% by mass of tin or indium. By forming the conductive material, the neck of the alloy layer is formed between the interface between the conductor wiring layer and the through conductor and the metal particles inside the through conductor, and between the conductor wiring layer and the particles inside the through conductor and the through conductor. Can be firmly connected, connection resistance can be reduced, and connection reliability can be improved in harsh environments.

  The method for producing a wiring board according to the present invention includes a step of forming an inner wall hole penetrating a predetermined portion of a liquid crystal polymer insulating layer, and a varnish containing a resin excluding the liquid crystal polymer to be a previously prepared inner wall layer. A step of forming an inner wall layer in the inner wall hole, a step of forming a through hole penetrating the inner wall layer formed in the inner wall hole, and a through conductor filled with a conductive material in the through hole A plurality of liquid crystal polymer insulation layers comprising an inner wall layer, a through conductor, and a conductor wiring layer produced by repeating the above steps, a step of transferring a conductor wiring layer to the liquid crystal polymer insulation layer, And laminating and multilayering.

  In such a wiring board manufacturing method, the inner wall layer can be easily formed without greatly changing from the printed board manufacturing process, and a wiring board with high connection reliability can be manufactured.

  Moreover, in the manufacturing method described above, by forming a coating layer containing a resin excluding the liquid crystal polymer on at least one main surface of the liquid crystal polymer insulating layer provided with the inner wall layer, the conductor wiring layer can be formed even at a low lamination temperature. It can be easily formed on the main surface of the liquid crystal polymer insulating layer via the coating layer.

  The method for producing a wiring board of the present invention produces a laminate in which a liquid crystal polymer insulating layer having substantially the same thickness and an inner wall layer sheet containing a resin other than the liquid crystal polymer to be an inner wall layer are laminated. A step of pressing a predetermined portion of the laminate from the inner wall layer sheet side, shifting a pressing portion of the inner wall layer sheet to the liquid crystal polymer insulating layer side, and the liquid crystal polymer insulating layer and the inner wall layer sheet A step of producing an integrated composite member, a step of forming a through hole penetrating the inner wall layer of the composite member, a step of filling the through hole with a conductor to form a through conductor, and the through conductor A step of transferring the conductor wiring layer to the main surface of the composite member formed with the conductor member and forming the conductor wiring layer on the main surface of the composite member; and an inner wall layer, a through conductor and a conductor wiring layer produced by repeating the above steps A plurality of liquids comprising Characterized by comprising the steps of multilayer laminated polymeric insulating layer.

  In such a method of manufacturing a wiring board, the formation of the inner wall hole and the formation of the inner wall layer can be performed simultaneously, so that the manufacturing process can be shortened and the cost can be reduced.

  Moreover, in the manufacturing method described above, by forming a coating layer containing a resin excluding the liquid crystal polymer on at least one main surface of the liquid crystal polymer insulating layer provided with the inner wall layer, the conductor wiring layer can be formed even at a low lamination temperature. It can be easily formed on the main surface of the liquid crystal polymer insulating layer via the coating layer.

  The method for manufacturing a wiring board according to the present invention includes a step of forming an inner wall hole penetrating a predetermined portion of a liquid crystal polymer insulating layer, and a varnish containing a resin excluding the liquid crystal polymer to be a previously prepared inner wall layer and covering layer. Immersing the liquid crystal polymer insulating layer in which the inner wall hole is formed to form an inner wall layer in the inner wall hole, and forming a coating layer on the surface of the liquid crystal polymer insulating layer in which the inner wall layer is formed; A step of forming a through hole penetrating the inner wall layer formed in the hole, a step of filling the through hole with a conductor to form a through conductor, and transferring the conductor wiring layer to the main surface of the coating layer And a step of laminating a plurality of the liquid crystal polymer insulating layers each including a coating layer, an inner wall layer, a through conductor, and a conductor wiring layer produced by repeating the above steps. And In such a method of manufacturing a wiring board, the covering layer and the inner wall layer can be formed at the same time, and the manufacturing process can be simplified and the cost can be reduced.

  For example, as shown in FIG. 1A, the wiring board of the present invention includes one or more liquid crystal polymer insulating layers 1 containing at least a liquid crystal polymer, an inner wall hole 2a penetrating the liquid crystal polymer insulating layer 1, An inner wall layer 3 containing a resin excluding a liquid crystal polymer provided in the inner wall hole 2a, a through hole 2b provided through the inner wall layer 3, and a through conductor 4 filled in the through hole 2b Has been.

  A conductor wiring layer 5 is formed on the main surface of the liquid crystal polymer insulating layer 1, and the through conductor 4 electrically connects the conductor wiring layers 5 arranged with the liquid crystal polymer insulating layer 1 sandwiched therebetween. ing.

  The inner wall layer 3 is located between the liquid crystal polymer insulating layer 1 and the through conductor 4, and has a function of fixing the through conductor 4 to the liquid crystal polymer insulating layer 1 and preventing contact between the through conductor 4 and the liquid crystal polymer insulating layer 1. doing. And even if the through conductor 4 contains a substance that reacts with the liquid crystal polymer insulating layer 4 to generate swelling, it is possible to prevent the reaction from occurring. Therefore, it is important that the inner wall layer 3 is made of a resin excluding the liquid crystal polymer, and a thermosetting resin or a thermoplastic resin excluding the liquid crystal polymer can be used.

  As such a thermosetting resin and thermoplastic resin, PPE (polyphenylene ether), BT resin (bismaleimide triazine), epoxy resin, polyimide resin, fluorine resin, phenol resin, polyamino bismaleimide and the like are preferably used.

  Among these resins, an epoxy resin is desirable because it has high adhesive strength with the through conductor and the liquid crystal polymer insulating layer and can be obtained at low cost. In addition, when it is necessary to consider transmission characteristics at high frequencies, fluororesins and PPE resins having excellent dielectric constant and dielectric loss are desirable.

  In addition, the inner wall layer 3 contains aluminum oxide, silicon oxide, titanium oxide, titanium oxide, barium oxide, strontium oxide, zirconium oxide, calcium oxide, zeolite, nitriding in the resin to adjust the thermal expansion coefficient and improve the mechanical strength. Filling material such as silicon, aluminum nitride, silicon carbide, potassium titanate, barium titanate, strontium titanate, calcium titanate, aluminum borate, barium stannate, barium zirconate, strontium zirconate, or cloth glass You may contain reinforcing materials, such as a glass cloth woven in the shape and the nonwoven fabric of a heat resistant resin fiber.

  In addition, the particle shape of the above filler includes a substantially spherical shape, a needle shape, a flake shape, and the like, and a substantially spherical shape is preferable from the viewpoint of filling properties. The particle diameter is usually about 0.1 to 15 μm, and is preferably smaller than the thickness of the inner wall layer 3.

  The inner wall layer 3 preferably has a thickness of 0.1 to 15 μm. By making the inner wall layer 3 thicker than 0.1 μm, the liquid crystal polymer insulating layer 1 and the through conductor 4 can be firmly connected, and the liquid crystal polymer insulating layer 1 and the through conductor 4 can be isolated. Further, cracks and peeling are less likely to occur between the liquid crystal polymer insulating layer 1 and the through conductor 4. For example, when the through conductor composition contains a low melting point metal such as indium or tin, even if there is a sudden endothermic reaction accompanying the melting of the low melting point metal, the inner wall layer 3 absorbs the influence and the liquid crystal polymer Cracks and peeling between the insulating layer 1 and the through conductor 4 can be prevented. Further, by setting the thickness of the inner wall layer 3 to 15 μm or less, the resin of the inner wall layer 3 hardly flows during heating and pressurization such as lamination and curing, and the conductor wiring layer 5 and the through conductor 4 are not deformed. Further, the pitch between the through conductors 4 can be narrowed, and a high-density wiring board can be manufactured.

  In addition, for example, when the difference in thermal expansion coefficient between the liquid crystal polymer insulating layer 1 and the through conductor 4 is large, the inner wall layer 3 relieves the stress. Therefore, the thickness of the inner wall layer 3 is particularly preferably 2 μm or more.

  When the thermal expansion coefficient of the liquid crystal polymer insulating layer 1 is A, the thermal expansion coefficient of the inner wall layer 3 is B, and the thermal expansion coefficient of the through conductor 4 is C, the thermal expansion coefficient containing the conductive metal is relatively high. In order to relieve the thermal stress between the large through conductor 4 and the liquid crystal polymer insulating layer 1 having a relatively small thermal expansion coefficient, it is desirable to satisfy the relationship of A <B <C. Since the thermal expansion coefficient of the inner wall layer 3 is between the thermal expansion coefficients of the liquid crystal polymer insulation layer 1 and the through conductor 4, the liquid crystal polymer insulation layer 1 and the penetration through the difference in thermal expansion coefficient between the liquid crystal polymer insulation layer 1 and the through conductor 4. Cracks and peeling between the conductors 4 are reduced.

  Further, as shown in FIG. 1B, it is desirable to form a coating layer 6 containing a resin excluding the liquid crystal polymer on the main surface of the liquid crystal polymer insulating layer 1. Since the liquid crystal polymer has a high melting point (300 ° C. or higher), the liquid layer polymer insulating layer 1 can be easily laminated at a low temperature of less than 300 ° C. by forming the coating layer 6 on the main surface of the liquid crystal polymer insulating layer 1. it can. Further, the conductor wiring layer 5 can be easily formed on the main surface of the liquid layer polymer insulating layer 1 via the coating layer 6.

  Moreover, it is desirable that the coating layer 6 is a thermosetting resin, and by making the coating layer 6 a thermosetting resin, the conductor wiring layer 5 is embedded in the coating layer 6 and the wiring board is heated, thereby providing a conductor. The thermosetting resin of the wiring layer 5 and the covering layer 6 is bonded, and the conductive wiring layer 5 and the covering layer 6 are firmly bonded to form a highly reliable wiring board.

  Further, it is desirable that the coating layer 6 is a thermoplastic resin. When the coating layer 6 is a thermoplastic resin, the conductor wiring layer 5 is embedded in the coating layer 6 so that the wiring board is softened by the thermoplastic resin. The conductor wiring layer 5 can be formed on the coating layer 6 by melting the coating layer 6 by heating up to a temperature and melting and bonding the conductor wiring layer 5 and the coating layer 6.

  In addition, it is desirable that the resin used for the covering layer 6 and the inner wall layer 3 is the same resin, and the covering layer 6 and the inner wall layer 3 are easily compatible, so that the reliability can be improved. In addition, the process can be simplified and the cost can be easily reduced.

  Further, the through conductor 4 may be formed of a conductive material containing 6 to 15% by mass of thermosetting resin, 2.5 to 10% by mass of silver, and 75 to 91.5% by mass of copper. desirable.

  The thermosetting resin contained in the conductive material acts as a resin for bonding metal powders, and has high bonding properties with metal powders such as epoxy resins, thermosetting polyphenylene ether resins, phenol resins, melamine resins, and alkyds. Thermosetting resins such as resins, urethane resins and imide resins, and mixtures thereof are used.

  By setting the content of the thermosetting resin contained in such a conductive material to 6% by mass or more, the viscosity of the conductive material tends to be low and the embedding property tends to be high, and by setting the content to 15% by mass or less. The resistance of the through conductor 4 can be made sufficiently low. Therefore, it is desirable that the content of the thermosetting resin contained in the conductive material is 6 to 15% by mass.

  Further, by setting the silver content in the conductive material to 2.5% by mass or more, there is a tendency that the bonding between the particles becomes sufficient and the resistance of the through conductor 4 tends to be low, and 10% by mass or less. Thus, in the reliability test, silver ion migration can be prevented and the cost of the conductive material can be reduced. Therefore, it is desirable that the content of silver contained in the conductive material is 2.5 to 10% by mass.

  Furthermore, by setting the content of copper contained in the conductive material to 75% by mass or more, the metal component filling amount in the conductive material becomes sufficient, and the conductivity can be ensured. Moreover, by setting it as 91.5 mass% or less, the viscosity of a electrically conductive material can be maintained low and embedding property can be maintained. Therefore, it is desirable that the content of copper contained in the conductive material is 75 to 91.5% by mass.

  In the wiring board of the present invention, the through conductor 4 is 6 to 15% by mass of thermosetting resin, 2.5 to 10% by mass of silver, 45 to 86.5% by mass of copper, and 5 to 30% by mass. It is desirable to be made of a conductive material containing tin or indium.

  In the process of heat-treating the wiring board, tin or indium that is a low melting point metal contained in the through conductor 4 is melted, and as a result, a metal of the conductive material contained in the through conductor and the conductor wiring layer 5 are formed to form an alloy. Therefore, the connection between the through conductor 4 and the conductor wiring layer 5 becomes strong, and a wiring board having excellent connection reliability can be obtained. In addition, since the inner wall layer 3 is formed between the through conductor 4 and the liquid crystal polymer insulating layer 1, cracks and peeling between the liquid crystal polymer insulating layer 1 and the through conductor 4 due to endothermic reaction are reduced.

  Moreover, as for content of tin or indium, 5-30 mass% is desirable. By setting the tin or indium content to 5% by mass or more, it becomes easy to form a three-dimensional through conductor connection by alloy formation, and the tin or indium content having a relatively large electric resistance is set to 30% by mass or less. As a result, the resistance of the through conductor 4 can be reduced.

  Such a through conductor 4 can be formed by, for example, a conventionally known screen printing method.

  The shape of the metal powder contained in the conductive material forming the through conductor 4 is preferably substantially spherical from the viewpoint of filling properties, and the average particle diameter is 2 μm or more, so that the metal powder The specific surface area can be reduced, and pasting becomes easy. Moreover, the embedding property and filling property of a conductive material can be made favorable by setting it as 10 micrometers or less. Accordingly, the average particle size of the metal powder is desirably 2 to 10 μm, particularly 3 to 7 μm, and most preferably 3 to 5 μm.

  Next, one form of the manufacturing method of the wiring board of this invention is demonstrated using Fig.2 (a)-FIG.3 (f).

  First, drilling, laser processing, die punching or the like is performed on a predetermined portion of the liquid crystal polymer insulating layer 1 as shown in FIG. 2A to form an inner wall hole 2a as shown in FIG. 2B. .

  Next, as shown in FIG. 2 (c), the inner wall hole 2a is filled with a varnish containing a resin excluding the liquid crystal polymer to be the inner wall layer 3 prepared in advance, and the inner wall layer 3 is formed in the inner wall hole 2a. To do. The filling of the varnish is performed using embedded printing or a dispenser.

  And as shown in FIG.3 (d), the through-hole 2b which penetrates the inner-wall layer 3 in the inner-wall layer 3 formed in the inner-wall hole 2a using means, such as a laser processing, a drill process, and die stamping, is formed. Form.

  Next, as shown in FIG. 3E, the through conductor 4 is formed by filling the through hole 2b with a conductive material by embedded printing, a dispenser, or the like.

  And as shown in FIG.3 (f), the conductor wiring layer 5 is transcribe | transferred to the liquid crystal polymer insulating layer 1, and the wiring board for one layer can be formed. Then, if necessary, a plurality of liquid crystal polymer insulating layers 1 each including the inner wall layer 3, the through conductor 4, and the conductor wiring layer 5 prepared by repeating the above steps are laminated and cured to be multilayered. Thus, a wiring board as shown in FIG. 1A can be manufactured.

  Further, in the above-described manufacturing method, after filling the inner wall layer 2a with the varnish to be the inner wall layer 3, the coating layer 6 is formed on the main surface of the liquid crystal polymer insulating layer 1, as shown in FIG. A wiring board can also be produced.

  Next, another method for manufacturing the wiring board of the present invention will be described with reference to FIGS. 4 (a) to 5 (f).

  First, the liquid crystal polymer insulating layer 1 having substantially the same thickness and the inner wall layer sheet 3 to be the inner wall layer 3 are manufactured by using a known sheet manufacturing method such as a doctor blade method.

  And as shown to Fig.4 (a), the liquid crystal polymer insulation layer 1 and the inner wall layer sheet | seat 3 used as the inner wall layer 3 are laminated | stacked.

  Next, as shown in FIG. 4B, a mold or the like is pressed from a side of the inner wall layer sheet 3 to a predetermined position of the laminate of the liquid crystal polymer insulating layer 1 and the inner wall layer sheet 3 that becomes the inner wall layer 3. The pressed portion of the inner wall layer sheet 3 is moved to the liquid crystal polymer insulating layer 1 side.

  And as shown in FIG.4 (c), the liquid crystal polymer insulation layer 1 extruded by the inner wall layer sheet | seat 3 from the inner wall layer sheet | seat 3 which has not transfered to the liquid crystal polymer insulation layer 1 side, and the liquid crystal polymer insulation layer 1 is shown. A composite member in which the liquid crystal polymer insulating layer 1 and the inner wall layer 3 are integrated is removed. Through such a process, the inner wall hole 2a and the inner wall layer 3 can be simultaneously formed in the liquid crystal polymer insulating layer 1.

  Then, as shown in FIG. 5 (d), a through hole 2b penetrating the inner wall layer 3 is formed in the inner wall layer 3 using means such as laser processing, drilling, and die punching. .

  Next, as shown in FIG. 5E, the through conductor 4 is formed by filling the through hole 2b with a conductive material by embedded printing, a dispenser, or the like.

  Next, as shown in FIG. 5 (f), the conductor wiring layer 5 previously formed on the film was transferred to the composite member in which the through conductor 4 was formed, and the through conductor 4 was formed. The conductor wiring layer 5 is formed on the composite member.

  Then, if necessary, a plurality of composite members each including the through conductor 4 and the conductor wiring layer 5 manufactured by repeating the above steps are stacked and cured to be multilayered as shown in FIG. A wiring board as shown can be manufactured.

  Further, in the above manufacturing method, after the liquid crystal polymer insulating layer 1 and the inner wall layer 3 are integrated as shown in FIG. 4C, the covering layer 6 is formed on the main surface of the composite member, A wiring board as shown in FIG. 1B can also be produced.

  Still another manufacturing method of the present invention will be described with reference to FIGS.

  First, as shown in FIG. 6A, an inner wall hole 2a is formed at a predetermined position of the liquid crystal polymer insulating layer 1 by laser processing, drilling, die punching, or the like.

  Next, as shown in FIG. 6 (b), the liquid crystal polymer insulating layer 1 provided with the inner wall hole 2a is immersed in a varnish that becomes the inner wall layer 3 and the coating layer 6 to form the inner wall layer 3 in the inner wall hole 2a. At the same time, a coating layer 6 is formed on the surface of the liquid crystal polymer insulating layer 1. And the through-hole 2b which penetrates the inner-wall layer 3 is formed in the inner-wall layer 3 formed in the inner-wall hole 2a by laser processing, drilling, die punching, etc.

  Next, as illustrated in FIG. 6C, the through conductor 4 is formed by filling the through hole 2 b with a conductive material using embedded printing, a dispenser, or the like.

  And as shown in FIG.6 (d), the conductor wiring layer 5 is aligned with the coating layer 6, and the conductor wiring layer 5 is heat-pressed at the temperature of 100 to 150 degreeC and the pressure of 1 to 5 MPa, and the coating layer 6 is covered. Transfer to 6. Then, if necessary, a plurality of composite members each including the through conductor 4 and the conductor wiring layer 5 produced by repeating the above steps are laminated and cured to be multilayered, thereby forming a multilayer structure as shown in FIG. A wiring board as shown in FIG.

  In addition, in the manufacturing method demonstrated using FIG. 6, the liquid crystal polymer insulating layer which formed the inner wall layer 2a by adjusting suitably the viscosity of the varnish used as the inner wall hole 2a and the inner wall layer 3 and the coating layer 6 1 can be immersed in the varnish, and in addition to the inner wall layer 3 and the coating layer 6, the through-hole 2 b can also be formed.

  In addition to the embodiment shown in FIG. 1, the wiring board of the present invention has, for example, a plurality of through holes 2 b in one inner wall layer 3 and a plurality of through conductors 4 in one inner wall layer 3. In this case, there is an advantage that the processing time is shortened.

  Needless to say, the plurality of liquid crystal polymer insulating layers 1 may be laminated without forming the wiring conductor layer 5 between the liquid crystal polymer insulating layers 1.

  Further, a build-up wiring layer may be further laminated on the wiring board of the present invention. In this case, reliability and higher density wiring can be realized together.

  Further, in the above example, the through conductor 4 is formed by filling a conductive paste. However, the through conductor 4 may be formed by plating with low resistance, and further, formed by plating and a conductive paste. In addition, the resistance of the through conductor 4 can be further reduced. Moreover, you may form by plating and resin.

  In addition, it is desirable to use a laser beam for the formation of the through hole 2b in that a fine through hole 2a can be formed.

  First, as the conductive material 4 filled in the through-hole 2b, metal powder with a blending ratio shown in Table 1, a bisphenol A type epoxy resin (manufactured by Yuka Shell Epoxy, Epicoat 828) as a thermosetting resin, and an amine as a curing agent An adduct curing agent (manufactured by Ajinomoto Co., Inc., MY-24) was kneaded with three rolls to produce a conductive paste.

  Next, spherical fused silica having an average particle size of 0.6 μm is added to the epoxy resin so that the content thereof is 30% by volume, MEK (methyl ethyl ketone) as a solvent, and further for promoting the curing of the resin The catalyst was added and mixed for 1 hour to prepare the varnish.

  Then, a varnish was applied with a doctor blade to the surface layer of the liquid crystal polymer insulating layer 1 having a melting point of 320 ° C. and a thickness of 50 μm, in which the inner wall hole 2a was not formed, and a coating layer 6 having a thickness of 10 μm was formed on both surfaces. 1 was produced.

  Next, an inner wall hole 2a having a hole diameter shown in Table 1 is formed by laser light at a predetermined portion of the liquid crystal polymer insulating layer 1 provided with the coating layer 6, and the inner wall hole 2a is filled with the varnish, whereby the liquid crystal polymer insulating layer is formed. 1 The coating layer 6 and the inner wall layer 3 were formed in the surface layer and the inner wall hole 2a.

  And the through-hole 2b of (phi) 50 micrometers which penetrates the inner-wall layer 3 was formed in the inner-wall layer 3 formed in the inner-wall hole 2a with the laser beam. In addition, the thickness of the inner wall layer 3 at this time was changed so as to have a value shown in Table 1.

  For comparison, a sample without the inner wall layer 3 was also prepared by not filling the varnish.

  Then, the above-described conductive paste was embedded in the through-hole 2b and the through-hole 2b of the liquid crystal polymer insulating layer 1 not provided with the inner wall layer 3 for comparison to form the through-conductor 4 by a conventionally known screen printing method.

  Next, the metal foil with a resin film having a thickness of 12 μm formed in a circuit shape is aligned with the liquid crystal polymer insulating layer 1 on which the through conductors 4 are formed, and is subjected to a pressure of 130 ° C. and 3 MPa by a vacuum laminator. After pressurizing for 30 seconds, the resin film was peeled off and the conductor wiring layer 5 was embedded in the coating layer 6. Finally, four liquid crystal polymer insulating layers 1 on which the conductor wiring layer 5, the inner wall layer 3 and the through conductor 4 are formed are stacked and heat-treated at a temperature of 200 ° C. for 5 hours under a pressure of 3 MPa for complete curing. To obtain a wiring board.

  Further, the liquid crystal polymer insulating layer 1 not having the inner wall layer 3 was laminated in the same manner.

  Note that the test substrate for conducting conduction reliability evaluation has two upper and lower conductor wiring layers 5 located inside through the liquid crystal polymer insulating layer 1 of the wiring substrate, and a through hole that electrically connects the two. A through-conductor chain was formed with the conductor 4. Conductive reliability is evaluated by conducting a temperature cycle test (TCT) in which the sample is 30 minutes at a temperature of −55 ° C. and 30 minutes at a temperature of 125 ° C. for one cycle. The conduction resistance was measured and evaluated by comparing the rate of change in conduction resistance before and after the test. Table 1 shows the results of evaluation of conduction reliability.

In addition, for the evaluation of blisters and cracks, the cross section of the wiring board is observed by SEM (scanning electron microscope analysis), each of the 50 through conductors is evaluated, and the number of blisters and cracks existing between the insulating layer and the through conductors is determined. evaluated. In addition, it was determined that there was a crack when there was a slight gap of less than 5 μm between the two layers forming the interface. Further, when there is a relatively large gap of 5 μm or more between the two layers forming the interface at the interface, it was determined that there was swelling.

  There is no inner wall layer 3 which is outside the scope of the present invention, and the sample No. 1 and 2, it was found that all the blisters occurred at the interface between the liquid crystal polymer insulating layer 1 and the through conductor 4, and the connection reliability was extremely inferior.

  In addition, although the through conductor 4 which is outside the scope of the present invention does not contain tin or indium, the sample no. 3, there was no swelling at the interface between the liquid crystal polymer insulating layer 1 and the penetrating conductor 4, but the adhesive strength at the interface between the liquid crystal polymer insulating layer 1 and the penetrating conductor 4 was low. Cracks were observed. This crack was very small with a gap of about 1 to 3 μm at the interface, but the resistance change rate after the temperature cycle was slightly increased, and it was found that long-term connection reliability was difficult. .

  On the other hand, the sample No. provided with the inner wall layer 3 of the present invention. Nos. 4 to 10 have no blisters at the interface between the liquid crystal polymer insulating layer 1 and the inner wall layer 3 and the interface between the inner wall layer 3 and the through conductor 4, and cracks are slightly observed in some samples. As shown in the figure, it showed very good reliability.

  Below, the sample of this invention is demonstrated in detail.

  Sample No. 5 in which the thickness of the inner wall layer 3 was changed. 4-7, sample No. 4 in which the thickness of the inner wall layer 3 is in the range of 0.1 to 15 μm. In Nos. 4 to 6, neither swelling nor cracking nor resin flow of the inner wall layer 3 can be confirmed, and it can be seen that the reliability is particularly excellent.

  On the other hand, the thickness of the inner wall layer 3 exceeds 15 μm and is 20 μm. In No. 7, although there is no problem in practical use, a slight resin flow is observed, and it is estimated that the through conductor 4 is deformed by pressurization during lamination.

  Further, the sample No. 1 in which the coefficient of thermal expansion of the inner wall layer 3 was changed. In Samples Nos. 8 to 10, the thermal expansion coefficient of the inner wall layer 3 is between the thermal expansion coefficients of the liquid crystal polymer insulating layer 1 and the through conductor 4. 9, there is no swelling at the interface between the liquid crystal polymer insulating layer 1 and the inner wall layer 3 and at the interface between the inner wall layer 3 and the through conductor 4, and no cracks are confirmed, which is very good. Showed reliability.

  On the other hand, Sample No. 2 in which the thermal expansion coefficient of the inner wall layer 3 is not between the thermal expansion coefficients of the liquid crystal polymer insulating layer 1 and the through conductor 4. In 8, 10, although a slight crack was observed at the interface between the inner wall layer 3 and the through conductor 4, the initial resistance and the rate of change in resistance after the temperature cycle were hardly affected.

It is the schematic which shows the outline of the wiring board of this invention. It is a longitudinal cross-sectional view which shows the manufacturing method of the wiring board of this invention. It is a longitudinal cross-sectional view which shows the manufacturing method of the wiring board of this invention. It is a longitudinal cross-sectional view which shows the manufacturing method of the wiring board of this invention. It is a longitudinal cross-sectional view which shows the manufacturing method of the wiring board of this invention. It is a longitudinal cross-sectional view which shows the manufacturing method of the wiring board of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Liquid crystal polymer insulating layer 2a ... Inner wall hole 2b ... Through-hole 3 ... Inner wall layer 4 ... Through-conductor 5 ... Conductor wiring layer 6 ... Covering layer

Claims (16)

One or more liquid crystal polymer insulating layers containing at least a liquid crystal polymer, an inner wall hole penetrating the liquid crystal polymer insulating layer, and an inner wall layer containing a resin excluding the liquid crystal polymer provided inside the inner wall hole; A wiring board comprising a through conductor provided through the inner wall layer. The wiring board according to claim 1, wherein the inner wall layer contains a thermosetting resin. The wiring board according to claim 1, wherein the inner wall layer contains a thermoplastic resin. The wiring board according to claim 1, wherein the inner wall layer has a thickness of 0.1 to 15 μm. 5. A <B <C, wherein A <B <C, where A is the thermal expansion coefficient of the liquid crystal polymer insulating layer, B is the thermal expansion coefficient of the inner wall layer, and C is the thermal expansion coefficient of the through conductor. A wiring board according to any one of the above. 6. The wiring board according to claim 1, wherein a coating layer containing a resin excluding the liquid crystal polymer is formed on at least one main surface of the liquid crystal polymer insulating layer. The wiring board according to claim 6, wherein the coating layer contains a thermosetting resin. The wiring board according to claim 6, wherein the coating layer contains a thermoplastic resin. The wiring board according to claim 6, wherein the coating layer and the inner wall layer contain the same resin. The through conductor is formed of a conductive material containing 6 to 15% by mass of thermosetting resin, 2.5 to 10% by mass of silver, and 75 to 91.5% by mass of copper. The wiring board according to claim 1. Conductive conductor in which through conductor contains 6 to 15% by mass of thermosetting resin, 2.5 to 10% by mass of silver, 45 to 86.5% by mass of copper and 5 to 30% by mass of tin or indium The wiring board according to claim 1, wherein the wiring board is made of a material. A step of forming an inner wall hole penetrating a predetermined portion of the liquid crystal polymer insulating layer, and filling the inner wall hole with a varnish containing a resin excluding the liquid crystal polymer to be the inner wall layer prepared in advance, and the inner wall hole has an inner wall A step of forming a layer, a step of forming a through hole penetrating the inner wall layer formed in the inner wall hole, a step of filling the through hole with a conductive material to form a through conductor, and the liquid crystal polymer insulation A step of transferring the conductor wiring layer to the layer, and a step of laminating a plurality of liquid crystal polymer insulating layers each including an inner wall layer, a through conductor, and a conductor wiring layer produced by repeating the above-described steps. A method of manufacturing a wiring board, comprising: A step of forming an inner wall hole penetrating a predetermined portion of the liquid crystal polymer insulating layer, and filling the inner wall hole with a varnish containing a resin excluding the liquid crystal polymer to be the inner wall layer prepared in advance, and the inner wall hole has an inner wall A step of forming a layer, a step of forming a coating layer containing a resin excluding the liquid crystal polymer on at least one main surface of the liquid crystal polymer insulating layer provided with the inner wall layer, the coating layer and the inner wall hole Forming a through hole penetrating the inner wall layer formed on the inner wall layer, filling the through hole with a conductive material to form a through conductor, and transferring the conductor wiring layer to the coating layer; And a step of laminating a plurality of liquid crystal polymer insulating layers each including an inner wall layer, a through conductor, a covering layer, and a conductor wiring layer produced by repeating the above-described steps, to form a multilayer A method for manufacturing a substrate. A step of producing a laminate in which a liquid crystal polymer insulating layer having substantially the same thickness and an inner wall layer sheet containing a resin other than the liquid crystal polymer to be an inner wall layer are laminated; and a predetermined portion of the laminate Pressing from the inner wall layer sheet side, moving the pressed portion of the inner wall layer sheet to the liquid crystal polymer insulating layer side, and producing a composite member in which the liquid crystal polymer insulating layer and the inner wall layer sheet are integrated; and A step of forming a through hole penetrating the inner wall layer of the composite member, a step of filling the through hole with a conductor to form a through conductor, and a main surface of the composite member on which the through conductor is formed A plurality of liquid crystal polymer insulating layers comprising: a step of transferring a conductor wiring layer to form a conductor wiring layer on the main surface of the composite member; and an inner wall layer, a through conductor, and a conductor wiring layer produced by repeating the above steps Multi-layered Method for manufacturing a wiring substrate, characterized by comprising the steps of, a. A step of producing a laminate in which a liquid crystal polymer insulating layer having substantially the same thickness and an inner wall layer sheet containing a resin other than the liquid crystal polymer to be an inner wall layer are laminated; and a predetermined portion of the laminate Pressing from the inner wall layer sheet side, moving the pressed portion of the inner wall layer sheet to the liquid crystal polymer insulating layer side, and producing a composite member in which the liquid crystal polymer insulating layer and the inner wall layer sheet are integrated; and A step of forming a coating layer containing a resin excluding a liquid crystal polymer on at least one main surface of the composite member, a step of forming a through hole penetrating the coating layer and the inner wall layer, and the through hole Filling the conductor with a conductor to form a through conductor; and transferring the conductor wiring layer to the main surface of the composite member on which the through conductor is formed to form a conductor wiring layer on the main surface of the composite member; Repeat the above steps Method for manufacturing a wiring substrate, characterized by comprising the steps of multilayer by laminating a plurality of composite members and the through conductor and the conductor wiring layer prepared by comprising a covering layer. A step of forming an inner wall hole penetrating a predetermined portion of the liquid crystal polymer insulating layer, and a liquid crystal polymer insulating layer in which the inner wall hole is formed in a varnish containing a resin excluding the liquid crystal polymer to be the inner wall layer and the coating layer prepared in advance A step of forming an inner wall layer in the inner wall hole, and forming a coating layer on the surface of the liquid crystal polymer insulating layer on which the inner wall layer is formed, and penetrating the inner wall layer formed in the inner wall hole A step of forming a through hole to be formed, a step of filling the through hole with a conductor to form a through conductor, a step of transferring a conductor wiring layer to the main surface of the coating layer, and the above steps are repeated. And a step of laminating a plurality of the liquid crystal polymer insulating layers each including a covering layer, an inner wall layer, a through conductor, and a conductor wiring layer.

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