JP2010221706A - Insulating resin film, and lamination sheet and wiring board using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an insulating resin film having a highly flame-retardant property, and to provide a lamination sheet and a wiring board using the insulating resin film. <P>SOLUTION: The insulating resin film has an insulating resin layer made of a resin composition on the surface of a base, wherein the resin composition contains a resin having a polycyclic structure and calcium silicate. The lamination sheet and the wiring board using the insulating resin film are also provided. Preferably, the resin composition further contains aluminum hydroxide, and the polycyclic structure is any of biphenyl structure, naphthalene structure, anthracene structure and dihydro-anthracene structure. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an insulating resin film used for electronic equipment, a laminated board using the same, and a wiring board.

  A typical laminate is generally obtained by curing and integrally molding a resin composition mainly composed of an epoxy resin and a glass woven fabric. In addition, as a build-up material used in a build-up type wiring board manufacturing process in which insulating layers are sequentially stacked and a circuit is formed by copper plating, a resin composition mainly composed of an epoxy resin is used. Epoxy resins have an excellent balance of insulation, heat resistance, cost, etc., but have the disadvantage of being easy to burn. For this reason, the flame retarding of a laminated board is indispensable, and the bromine type flame retardant was conventionally used (refer patent document 1, 2). However, due to increasing environmental awareness, there is an active movement to regulate materials including electronic components that may generate undesirable substances for the environment during combustion. For this reason, hydroxides such as aluminum hydroxide and magnesium hydroxide (see Patent Document 3), phosphorus compounds such as phosphate esters (see Patent Document 4), and nitrogen compounds such as melamine are flame retardants (see Patent Document 5). It is used as However, there are also known problems that the flame retardant function does not appear unless a large amount of hydroxide is blended, the phosphorus compound is corrosive, and the nitrogen compound has a low flame retardant effect. Silicates, carbonates, metal oxides and the like are also known to exhibit a flame retardant effect (see Patent Document 6).

Japanese Patent Publication No. 61-1456 Japanese Patent No. 3290296 JP 2002-212394 A Japanese Patent No. 3611435 Japanese Patent Publication No. 61-58306 Japanese Patent No. 3465417

A hydroxide such as aluminum hydroxide exhibits a flame retardant effect, but a large amount of blending is required to exhibit sufficient flame retardancy. However, there are many problems such as a decrease in insulation due to an increase in interface due to a large amount of blending and a decrease in heat resistance due to decomposition of a large amount of hydroxide. For this reason, the technique which can reduce the compounding quantity of a hydroxide was calculated | required.
The object of the present invention is to solve the above-mentioned problems and provide an insulating resin film having high flame retardancy, a laminate using the same, and a wiring board.

As a result of diligent research to solve the above problems, the present inventors have found that using a resin having a polycyclic structure and having a film-forming ability alone with calcium silicate is compared with other calcium compounds. As a result, it was found that particularly high flame retardancy was exhibited. The film forming ability mentioned here means that a resin coating film having a uniform thickness is obtained after solvent drying.
The present invention relates to the following.
(1) Insulating resin film having an insulating resin layer made of a resin composition on a substrate surface, wherein the resin composition contains a resin having a polycyclic structure and calcium silicate. Resin film.
(2) The insulating resin film described above, wherein the resin composition further contains aluminum hydroxide.
(3) The insulating resin film described above, wherein the resin having a polycyclic structure has any one of a biphenyl structure, a naphthalene structure, an anthracene structure, and a dihydroanthracene structure.
(4) The insulating resin film described above, wherein the resin having a polycyclic structure is an epoxy resin.
(5) The insulating resin film described above, wherein the epoxy resin contains one or more crystalline epoxy resins.
(6) The epoxy resin includes one or more of a biphenyl novolac type epoxy resin of the following general formula (1), an anthracene type epoxy resin of the general formula (2), and a dihydroanthracene type epoxy resin of the general formula (3). The insulating resin film as described above.

（但し、一般式（１）中、Ｒ¹〜Ｒ⁴は同一、又は互いに異なるＣ_mＨ_2m+1基を、ｍは０又は１以上の整数を表す。ｎは１以上の整数を表す。）

(In the general formula (1), R ^{1 to} R ⁴ are the same or different C _m H _{2m + 1} groups, m represents 0 or an integer of 1 or more, and n represents an integer of 1 or more. )

（但し、一般式（２）中、Ｒ¹〜Ｒ⁴は同一、又は互いに異なるＣ_mＨ_2m+1基を、ｍは０又は１以上の整数を表す。）

(However, in General Formula (2), R ^{1 to} R ⁴ are the same or different C _m H _{2m + 1} groups, and m represents 0 or an integer of 1 or more.)

（但し、一般式（３）中、Ｒ¹は同一、又は互いに異なるＣ_m'Ｈ_2m'+1基を表し、ｍ’は０又は１以上の整数で、ｎは０〜４の整数を表す。Ｒ²は同一、又は互いに異なるＣ_m'Ｈ_2m'+1基を表し、ｍ’は０又は１以上の整数で、ｍは０〜４の整数を示す。）

(In the general formula (3), R ¹ represents the same or different C _{m ′} H _{2m ′ + 1} groups, m ′ represents 0 or an integer of 1 or more, and n represents an integer of 0 to 4. R ² represents the same or different C _{m ′} H _{2m ′ + 1} groups, m ′ is 0 or an integer of 1 or more, and m is an integer of 0 to 4.

(7) The insulating resin film described above, wherein the base material is PET (polyethylene terephthalate) or metal foil.
(8) A laminated board obtained by laminating the insulating resin film on one side or both sides of the substrate.
(9) A wiring board obtained by processing a circuit on the laminated board.

  ADVANTAGE OF THE INVENTION According to this invention, a highly flame-retardant resin composition and insulating resin film can be obtained by mix | blending calcium silicate with resin which has a polycyclic structure and has film-forming ability only by resin. .

  The present invention provides a base material for an insulating resin layer comprising a resin composition having a flame retardant greatly improved by uniformly dispersing calcium silicate in a resin having a polycyclic structure and having a film-forming ability alone. The present invention relates to an insulating resin film provided on the surface. That is, the insulating resin film of the present invention is an insulating resin film provided with an insulating resin layer made of a resin composition on a substrate surface, wherein the resin composition contains a resin having a polycyclic structure and calcium silicate. It is characterized by doing.

  The resin having a polycyclic structure used in the present invention is not particularly limited as long as it has a polycyclic structure and the resin alone has a film-forming ability. Epoxy resins that are superior in terms of the above are preferably used. Moreover, it is preferable that the epoxy resin to be used contains one or more crystalline epoxy resins. Further, the epoxy resin to be used may be any one as long as it has two or more epoxy groups in the molecule and has a polycyclic structure. For example, naphthalene type epoxy resin, naphthalene novolak type epoxy resin, anthracene Type epoxy resin, dihydroanthracene type epoxy resin, biphenyl type epoxy resin, biphenyl novolac type epoxy resin, etc., especially condensation polythene such as naphthalene type epoxy resin, anthracene type epoxy resin, dihydroanthracene type epoxy resin, biphenyl novolac type epoxy resin, etc. Epoxy resins having a cyclic structure are preferred. These resins may have any molecular weight, and several types may be used in combination. Moreover, it is preferable to use the epoxy resin which prepolymerized by making a part of epoxy resin to be used react.

  Moreover, the epoxy resin to be used is at least one of the following biphenyl novolac type epoxy resin of the general formula (1), the anthracene type epoxy resin of the general formula (2), and the dihydroanthracene type epoxy resin of the general formula (3). It is preferable to include.

（但し、一般式（１）中、Ｒ¹〜Ｒ⁴は同一、又は互いに異なるＣ_mＨ_2m+1基を、ｍは０又は１以上の整数を表す。ｎは１以上の整数を表す。）

(In the general formula (1), R ^{1 to} R ⁴ are the same or different C _m H _{2m + 1} groups, m represents 0 or an integer of 1 or more, and n represents an integer of 1 or more. )

Examples of the C _m H _{2m + 1} group in the general formula (1) include alkyl groups such as methyl, ethyl, propyl, iso-propyl, and butyl. Usually, n is an integer of 1-10. The C _m H _{2m + 1} group is preferably hydrogen or a linear or branched alkyl group having m = 1 to 20.

（但し、一般式（２）中、Ｒ¹〜Ｒ⁴は同一、又は互いに異なるＣ_mＨ_2m+1基を、ｍは０又は１以上の整数を表す。）

(However, in General Formula (2), R ^{1 to} R ⁴ are the same or different C _m H _{2m + 1} groups, and m represents 0 or an integer of 1 or more.)

Examples of the C _m H _{2m + 1} group in the general formula (2) include alkyl groups such as methyl, ethyl, propyl, iso-propyl, and butyl. The C _m H _{2m + 1} group is preferably hydrogen or a linear or branched alkyl group having m = 1 to 20.

（但し、一般式（３）中、Ｒ¹は同一、又は互いに異なるＣ_m'Ｈ_2m'+1基を表し、ｍ’は０又は１以上の整数で、ｎは０〜４の整数を表す。Ｒ²は同一、又は互いに異なるＣ_m'Ｈ_2m'+1基を表し、ｍ’は０又は１以上の整数で、ｍは０〜４の整数を示す。）

(In the general formula (3), R ¹ represents the same or different C _{m ′} H _{2m ′ + 1} groups, m ′ represents 0 or an integer of 1 or more, and n represents an integer of 0 to 4. R ² represents the same or different C _{m ′} H _{2m ′ + 1} groups, m ′ is 0 or an integer of 1 or more, and m is an integer of 0 to 4.

Examples of the C _{m ′} H _{2m ′ + 1} group in the general formula (3) include alkyl groups such as methyl, ethyl, propyl, iso-propyl, and butyl. The C _{m ′} H _{2m ′ + 1} group is preferably hydrogen or a linear or branched alkyl group having m ′ = 1 to 20.

  Moreover, as an epoxy resin which has a biphenyl structure as a commercial item, NC-3000-H (Nippon Kayaku Co., Ltd., brand name) etc. are as an epoxy resin which has a dihydroanthracene structure, YX-8800 (Japan epoxy resin). As an epoxy resin having a naphthalene structure, ESN-175 (manufactured by Toto Kasei Co., Ltd., trade name) and the like can be given.

  The calcium silicate used in the present invention may have any shape, but is preferably spherical in order to reduce the influence on the fluidity of the resin. Moreover, it is preferable when using a solvent that it is nonporous. The average particle size may be any particle size, but is preferably 50 μm or less, more preferably 20 μm or less, and particularly preferably 10 μm or less in order to obtain a flame retardant effect in order to enhance dispersibility in the resin. From the viewpoint of viscosity, the average particle size is preferably 0.01 μm or more, more preferably 0.1 μm or more, and particularly preferably 1 μm or more. The average particle size can be measured using a dynamic light scattering method. For example, particles are uniformly dispersed in an appropriate organic solvent by ultrasonic waves, etc., and a particle size distribution of the particles is created on a mass basis using a concentrated particle size analyzer [FPAR-1000; manufactured by Otsuka Electronics Co., Ltd.] It is measured by taking the median diameter as the average particle diameter.

  In the resin composition, the blending ratio of the resin having a polycyclic structure and calcium silicate is preferably 4 to 50 parts by mass, and 6 to 40 parts by mass with respect to 100 parts by mass of the resin having a polycyclic structure. The range of parts is more preferable, and 7 to 30 parts by mass is particularly preferable. When the amount is less than 4 parts by mass with respect to 100 parts by mass of the resin having a polycyclic structure, the flame-retardant effect is poor, and when it exceeds 50 parts by mass, the handleability of the polycyclic resin may be reduced. In order to uniformly disperse calcium silicate, it is effective to use a dispersing device such as a raking machine, a homogenizer, a bead mill, or a nanomizer, or a crushing device.

  In the resin composition, it is preferable to add a solvent in order to dissolve and mix the resin having a polycyclic structure and calcium silicate. The solvent may be any solvent as long as it can dissolve and disperse the resin having a polycyclic structure and calcium silicate, and in particular, acetone, methyl ethyl ketone, methyl butyl ketone, toluene, xylene, ethyl acetate, N, N-dimethylformamide, N, N-dimethylacetamide, ethanol, ethylene glycol monomethyl ether, propylene glycol monomethyl ether acetate and the like are preferable because of excellent solubility. The amount of these solvents may be any amount as long as the resin having a polycyclic structure can be dissolved and dispersed with calcium silicate, but the total amount of the resin having a polycyclic structure and calcium silicate is 100 parts by mass. On the other hand, the range of 30-300 mass parts is preferable, and the range of 50-200 mass parts is more preferable. Moreover, you may use said solvent in combination.

  In the resin composition, an inorganic filler may be further added, or an additive may be added. As the inorganic filler, silica, alumina, aluminum hydroxide, calcium carbonate, clay, talc, silicon nitride, boron nitride, titanium oxide, barium titanate, lead titanate, strontium titanate, etc. can be used. Aluminum hydroxide is preferred. The blending amount of the inorganic filler is preferably 300 parts by mass or less, preferably 200 parts by mass or less with respect to 100 parts by mass of the total amount of the resin having a polycyclic structure and calcium silicate. The product (material for multilayer wiring board) is more preferable in order to obtain uniform and good handleability. Moreover, it is preferable to set it as 0.5 mass part or more, and it is more preferable to set it as 1 mass part or more. In order to disperse the inorganic filler uniformly, it is effective to use a raking machine, a homogenizer, a bead mill, a nanomizer or the like.

  As the additive, various silane coupling agents, curing accelerators, antifoaming agents and the like can be used. This blending amount is preferably 5 parts by mass or less, preferably 3 parts by mass or less for maintaining the characteristics of the resin composition with respect to 100 parts by mass of the total amount of the resin having a polycyclic structure and calcium silicate. More preferred. Moreover, it is preferable to set it as 0.1 mass part or more, and it is more preferable to set it as 1 mass part or more.

  The insulating resin film of the present invention is usually obtained by applying and drying the above-described resin composition on the substrate surface. For example, the varnish of the resin composition is applied to the substrate surface using a comma type coater which is a kind of bar coater, and after application, it is usually dried at 40 to 200 ° C. for about 1 to 60 minutes, and the thickness is 10 to 100 μm. An insulating resin film having an insulating resin layer can be obtained. The base material only needs to be able to apply and dry the resin composition. A metal foil such as copper or aluminum, a resin film such as polyester or polyimide, or a release agent on the surface of these resin films. Although what apply | coated etc. can be used, PET (polyethylene terephthalate), copper foil, aluminum foil, etc. are preferable. The thickness of the resin film or metal foil is usually 3 to 200 μm. In addition, the metal foil is not limited to a single layer foil, and may be a composite foil having two or more layers. Moreover, when copper foil is used for the base material, there is an advantage that the copper foil can be used as a circuit conductor as it is, and when the base material is treated with a release agent, an insulating resin film is formed from the base material. It is preferable to improve the workability when peeling only the base material (support base material) after peeling the substrate or laminating the insulating resin film with the base material (support base material) on the substrate.

  The laminate of the present invention can be obtained by laminating and forming the insulating resin film on one side or both sides of the substrate. Lamination molding conditions are not particularly limited, and an insulating resin film coated on a metal foil may be disposed at the time of lamination molding to form a metal-clad laminate. Alternatively, a metal foil may be provided on the insulating resin film from which the base material has been peeled during lamination molding to form a metal-clad laminate. Examples of the substrate include a resin plate, an inner layer circuit board, and a copper clad laminate. The heating temperature at the time of producing the laminated plate is 130 to 250 ° C., more preferably 160 to 200 ° C., and the pressure is 0.5 to 10 MPa, more preferably 1 to 4 MPa. It is determined appropriately depending on the capacity, the thickness of the target laminate, and the like.

  The wiring board of the present invention can be obtained by subjecting the above laminated board to general circuit processing. As general circuit processing, a circuit can be formed by an etching method, an additive method, a semi-additive method, or the like.

Hereinafter, the present invention will be described in detail based on examples, but the present invention is not limited thereto.
Example 1
In a four-neck separable flask equipped with a thermometer, a condenser tube, and a stirrer, dihydroanthracene type epoxy resin (YX-8800, product name of Japan Epoxy Resin Co., Ltd.) 100 g, benzoguanamine (Kanto Chemical) 7.4g) and cresol novolak resin (KA-1165, trade name of Dainippon Ink & Chemicals, Inc.) 25.4g, propylene glycol monomethyl ether acetate (manufactured by Kanto Chemical Co., Ltd.) 127g as a solvent, The reaction was performed at 140 ° C. for 5 hours. Thereafter, biphenyl novolac type epoxy resin (NC-3000-H, Nippon Kayaku Co., Ltd., trade name) 65.8 g, cresol novolak resin (KA-1165, trade name, manufactured by Dainippon Ink & Chemicals, Inc.) 59.1 g, propylene 125 g of glycol monomethyl ether acetate (manufactured by Kanto Chemical Co., Inc.) was added and dissolved by heating at 100 ° C. for 30 minutes. Thereafter, 170.4 g of silica (SO-G1, trade name manufactured by Admatechs Co., Ltd.), 208.3 g of aluminum hydroxide (HP-350, trade name of Showa Denko KK), calcium silicate ground in a mortar (Kanto Chemical) Co., Ltd., average particle size 10 μm) 18.9 g, propylene glycol monomethyl ether acetate (manufactured by Kanto Chemical Co., Ltd.) 100 g, curing accelerator 2PZ-CN (trade name of Shikoku Kasei Kogyo Co., Ltd.): 0.5 g Stir for 1 hour to obtain the desired resin composition varnish.

  The prepared resin composition varnish was applied onto a product name F2-WS copper foil (Rz: 2.0 μm, Ra: 0.3 μm) having a thickness of 18 μm so that the insulating resin layer thickness was 0.05 mm, and 160 ° C. Was heated for 5 minutes to obtain a semi-cured (B stage state) insulating resin film. An insulating resin film prepared on both sides of MCL-E-679FG (trade name, manufactured by Hitachi Chemical Co., Ltd.) having a thickness of 0.21 mm from which the copper foil has been removed is placed, and a press at 185 ° C., 90 minutes, 1.0 MPa. A laminate with an insulating resin film was produced under the conditions. This laminated plate with an insulating resin film was immersed in an aqueous solution of 150 g / l ammonium persulfate at 40 ° C. for 20 minutes to remove the copper foil by etching. Then, the sample was cut out to 13 mm x 130 mm, and flame retardance (average burning time (n = 5)) was evaluated based on the UL-94 vertical method.

Example 2
Except for changing silica (SO-G1, trade name manufactured by Admatechs Co., Ltd.) to 151.5 g, calcium silicate crushed in a mortar (manufactured by Kanto Chemical Co., Inc., average particle size 10 μm) to 37.9 g, all Examples 1 was performed.

Example 3
Except that 113.6 g of silica (SO-G1, trade name manufactured by Admatechs Co., Ltd.) and calcium silicate crushed in a mortar (manufactured by Kanto Chemical Co., Ltd., average particle size 10 μm) were changed to 75.8 g, all Examples 1 was performed.

Comparative Example 1
In a four-neck separable flask equipped with a thermometer, a condenser tube, and a stirrer, dihydroanthracene type epoxy resin (YX-8800, trade name of Japan Epoxy Resin Co., Ltd.) 100 g, benzoguanamine (Kanto Chemical) as a curing agent for epoxy resin 7.4g) and cresol novolak resin (KA-1165, trade name of Dainippon Ink & Chemicals, Inc.) 25.4g, propylene glycol monomethyl ether acetate (manufactured by Kanto Chemical Co., Ltd.) 127g as a solvent, The reaction was carried out at 140 ° C. for 5 hours. Thereafter, biphenyl novolac type epoxy resin (NC-3000-H, Nippon Kayaku Co., Ltd., trade name) 65.8 g, cresol novolak resin (KA-1165, trade name, manufactured by Dainippon Ink & Chemicals, Inc.) 59.1 g, propylene Glycol monomethyl ether acetate (manufactured by Kanto Chemical Co., Inc.) 1
25 g was added and dissolved by heating at 100 ° C. for 30 minutes. Thereafter, 151.5 g of silica (SO-G1, trade name manufactured by Admatechs), 255.7 g of aluminum hydroxide (HP-350, trade name of Showa Denko KK), propylene glycol monomethyl ether acetate (Kanto Chemical Co., Ltd.) 100 g, curing accelerator 2PZ-CN (trade name of Shikoku Kasei Kogyo Co., Ltd.): 0.5 g was added and stirred for 1 hour to obtain a resin composition varnish.

  The prepared resin composition varnish was applied onto a product name F2-WS copper foil (Rz: 2.0 μm, Ra: 0.3 μm) having a thickness of 18 μm so that the insulating resin layer thickness was 0.05 mm, and 160 ° C. Was heated for 5 minutes to obtain a semi-cured (B stage state) insulating resin film. An insulating resin film prepared on both sides of MCL-E-679FG (trade name, manufactured by Hitachi Chemical Co., Ltd.) having a thickness of 0.21 mm from which the copper foil has been removed is placed, and a press at 185 ° C., 90 minutes, 1.0 MPa. A laminate with an insulating resin film was produced under the conditions. This laminated plate with an insulating resin film was immersed in an aqueous solution of 150 g / l ammonium persulfate at 40 ° C. for 20 minutes to remove the copper foil by etching. Then, the sample was cut out to 13 mm x 130 mm, and the flame retardance was evaluated based on the UL-94 vertical method.

Comparative Example 2
All except that aluminum hydroxide (HP-350, trade name manufactured by Showa Denko KK) was changed to 208.3 g and calcium borate (UB powder, trade name manufactured by Kinsei Nimatec Co., Ltd.) 43.1 g was added. Performed as in Example 1.

Comparative Example 3
Comparative Example 1 except that aluminum hydroxide (HP-350, trade name manufactured by Showa Denko KK) was changed to 208.3 g, and 51.1 g of calcium carbonate (manufactured by Kanto Chemical Co., Ltd.) pulverized in a mortar was further added. The same was done.

  Table 1 shows the flammability test results of the samples produced in the examples. On the other hand, Table 2 shows the flammability test results of the samples produced in the comparative examples.

（表２中の空欄は、配合無しを表す。）

(The blank in Table 2 indicates no blending.)

From the comparison of Examples 1 to 3 in Table 1, it can be seen that the average combustion time decreases as the calcium silicate content increases. Further, the average combustion time of Example 2 in Table 1 is 6.3 s (seconds), whereas the average combustion time of Comparative Examples 1 to 3 in Table 2 is 9.4 to 10.6 s (seconds). Compared to Example 2, it was significantly longer (bad). Therefore, it turns out that the mixing | blending of a calcium silicate is especially effective for the flame retardance improvement of a polycyclic compound (resin which has a polycyclic structure).
According to the present invention, a highly flame-retardant insulating resin film made of a resin composition can be obtained by blending calcium silicate with a resin having a polycyclic structure and having a film-forming ability alone. it can.

Claims (9)

  An insulating resin film comprising an insulating resin layer made of a resin composition on a substrate surface, wherein the resin composition contains a resin having a polycyclic structure and calcium silicate.   The insulating resin film according to claim 1, wherein the resin composition further contains aluminum hydroxide.   The insulating resin film according to claim 1 or 2, wherein the resin having a polycyclic structure has any one of a biphenyl structure, a naphthalene structure, an anthracene structure, and a dihydroanthracene structure.   The insulating resin film according to claim 1, wherein the resin having a polycyclic structure is an epoxy resin.   The insulating resin film according to claim 4, wherein the epoxy resin contains one or more crystalline epoxy resins. The epoxy resin includes one or more of a biphenyl novolac type epoxy resin of the following general formula (1), an anthracene type epoxy resin of the general formula (2), and a dihydroanthracene type epoxy resin of the general formula (3). The insulating resin film according to claim 4 or 5.

(In the general formula (1), R ^{1 to} R ⁴ are the same or different C _m H _{2m + 1} groups, m represents 0 or an integer of 1 or more, and n represents an integer of 1 or more. )

(However, in General Formula (2), R ^{1 to} R ⁴ are the same or different C _m H _{2m + 1} groups, and m represents 0 or an integer of 1 or more.)

(In the general formula (3), R ¹ represents the same or different C _{m ′} H _{2m ′ + 1} groups, m ′ represents 0 or an integer of 1 or more, and n represents an integer of 0 to 4. R ² represents the same or different C _{m ′} H _{2m ′ + 1} groups, m ′ is 0 or an integer of 1 or more, and m is an integer of 0 to 4.   The insulating resin film according to claim 1, wherein the base material is PET (polyethylene terephthalate) or a metal foil.   A laminate formed by laminating the insulating resin film according to any one of claims 1 to 7 on one side or both sides of a substrate.   A wiring board obtained by processing a circuit on the laminated board according to claim 8.