JPH07170074A - Manufacture of ceramic multilayer circuit board - Google Patents

Abstract

PURPOSE:To use metal of low resistance and low melting point in the manufacture of a ceramic multilayer circuit board by a method wherein material of high volatility is filled in a through-hole bored in a ceramic green sheet, a conductor circuit pattern formed of the same material is provided to the surface of the green sheet, the ceramic green sheets are laminated and sintered to evaporate the material concerned, and melt of gold or the like is poured in a gap produced by evaporation. CONSTITUTION:Through-holes 2 are bored in a ceramic green sheet, and then highly volatile material which is evaporated at the sintering temperature of the green sheet is filled into the through-holes 2, and a conductor circuit pattern of highly volatile material is formed on the surface of the green sheet. The green sheets are laminated and sintered to remove the highly volatile material by evaporation. Melt of at least one metal selected out of gold, silver, and copper is poured in a gap 3 produced by sintering to form a conductor circuit and also filled into the through-hole 2. Thus a ceramic multilayer circuit board of this constitution can be kept high in thermal conductivity and free from a signal propagation delay.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a ceramic multilayer circuit board.

[0002]

2. Description of the Related Art In recent years, with the rapid development of semiconductor integrated circuits, various electronic devices have been made smaller and have higher performance. For miniaturization of electronic devices, in addition to miniaturization of various elements, high density on a circuit board is required to be achieved. A multi-layer circuit board has been attracting attention for increasing the density. In the multilayer circuit board, many elements can be mounted on the conductor circuit on the surface thereof, and further, a complicated conductor circuit for connecting to the conductor circuit through a through hole can be provided inside.

However, when many elements are mounted on the multi-layer circuit board, a large amount of heat is generated to raise the temperature of the circuit board. Therefore, when sufficient heat is not radiated from the circuit board, the LSI element and the like are first used. This has an adverse effect on the mounting elements that are mounted, and is a hindrance to higher density mounting. For this reason, ceramic multilayer circuit boards having good thermal conductivity have been attracting attention and many have been developed in place of multilayer circuit boards made of synthetic resin or glass having poor thermal conductivity.

In the ceramic multi-layer circuit board, it is important that the conductor material has low electric resistance in addition to good thermal conductivity. When the electric resistance of the conductor material is high, the problem of inducing a delay in the signal propagation speed is caused. Therefore, it is important to select a material having a low electric resistance for the conductor circuit. Examples of the conductor material having low electric resistance include gold (2.4 × 10 ⁻⁶ Ω · cm; 20 ° C.), silver (1.6 × 10 ⁻⁶ Ω · cm; 20 ° C.), and copper (1.7 ×). 1
0 ^-6 Ω · cm; 20 ° C) and aluminum (2.8 ×)
10 ⁻⁶ Ω · cm; 20 ° C.) and the like are known. However, when manufacturing a ceramic multilayer circuit board, a step of sintering at a temperature of 1000 ° C. or higher is usually required in order to densify the ceramic of the base material, but all of the conductor materials have a melting point of 1000. ℃ around (eg gold; 1064
C., silver; 961.9.degree. C., copper; 1085.degree. C., aluminum; 660.4.degree. C.), so even if a conductor circuit is formed before sintering, the conductor material is almost melted during the sintering process. Cannot hold the shape of. Therefore, conventionally, tungsten or molybdenum having a relatively high melting point has been used as the conductor material of the ceramic multilayer circuit board. However, these materials have high electric resistance (tungsten; 5.5 × 10 ⁻⁶ Ω · cm, molybdenum; 5.6 ×).
Since it is 10 ⁻⁶ Ω · cm), there is the problem of the signal propagation speed delay described above.

Many attempts have been made to utilize a conductor material such as gold having a low electric resistance and a low melting point for a ceramic multilayer circuit board having a good thermal conductivity. For example, in JP-A 1-219066, JP-A-2-196066 and JP-A-2-221162, glass powder or inorganic material powder is mixed with aluminum nitride having good thermal conductivity and the sintering temperature is 800 to 1000. It is disclosed that the conductor material having low resistance and low melting point such as gold can be used by lowering the temperature to about 0 ° C. However, the base material of the multilayer circuit board manufactured by using such a method has a thermal conductivity of 10 to 20 W / m · K, which is significantly lower than the thermal conductivity (320 W / m · K) originally possessed by aluminum nitride. Will result.

On the other hand, a multi-layer circuit in which an internal conductor circuit of any one of gold, silver and copper is formed on a base material of aluminum nitride, focusing on the fact that the above-mentioned conductor material such as gold has poor wettability with aluminum nitride. An example of manufacturing a substrate is also JP-A-2-
No. 197189. However, in the above method, since the ceramic material is sintered at a temperature of around 1800 ° C., the components in the ceramic, especially the sintering aid, are mixed in the conductor material (especially remarkable when gold is used). As a result, there arises a problem that the electric resistance of the conductor circuit increases.

As described above, the conductor material has a high melting point in order to exhibit the original thermal conductivity of the ceramic material,
It is necessary to use a material having a relatively high electric resistance, while the thermal conductivity of the ceramic material must be sacrificed in order to use a metal having a low electric resistance, such as gold, as the conductor material. Therefore, it has been difficult to manufacture a ceramic multilayer circuit board having both thermal conductivity and low resistance of a conductor circuit by the conventional techniques.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems of the prior art, and maintains the high thermal conductivity inherent to ceramic materials while having a low electric resistance and a low melting point as a conductor material. An object of the present invention is to provide a method for manufacturing a ceramic multi-layer circuit board that enables the use of the above metal.

[0009]

According to the method for manufacturing a ceramic multilayer circuit board according to the present invention, ceramic powder is dispersed in a desired solvent to prepare a ceramic slurry, and the slurry is formed into a sheet and dried. A step of producing a green sheet, and after forming a through hole in the green sheet, an easily volatile material that volatilizes at the sintering temperature of the green sheet is embedded in the through hole of the green sheet, and the green sheet is easily formed on the surface of the sheet. A step of forming a conductor circuit-shaped pattern made of a volatile material; a step of stacking a plurality of the green sheets and then sintering and volatilizing and removing the easily volatile material; and a void formed by the sintering. A conductor circuit is formed by pouring a melt of at least one metal selected from gold, silver, copper or aluminum into While formed and is characterized by comprising a step of embedding said metal in said through hole.

The method for producing a ceramic multilayer circuit board according to the present invention comprises the steps of dispersing ceramic powder in a desired solvent to prepare a slurry, making the ceramic slurry into a sheet, and drying the slurry to produce a ceramic green sheet. After forming a through hole in the green sheet, a volatile material that volatilizes at the sintering temperature of the green sheet is embedded in the through hole of the green sheet and a conductor circuit made of the volatile material on the surface of the sheet. A step of forming a pattern of shape, a step of stacking a plurality of the green sheets, sintering and volatilizing and removing the easily volatile material, and gold, silver, copper or the voids formed by the sintering. A slurry containing aluminum,
Alternatively, a step of filling a slurry containing a substance that is converted into gold, silver, copper or aluminum by heat treatment at high temperature and then forming a conductor circuit by heat treatment at high temperature and burying the metal in the through hole And is provided.

The present invention will be described in detail below. (First Step) First, if necessary, a sintering aid is added to the ceramic powder, sufficiently mixed, and a binder is further added, followed by kneading and dispersing in a predetermined solvent to obtain a ceramic having a desired viscosity. Prepare the rally. Subsequently, the slurry is formed into a sheet by, for example, a doctor blade method to produce a ceramic green sheet.

Examples of the ceramic powder include aluminum nitride, alumina, mullite, silicon nitride, zirconia, magnesia and the like. As the binder, for example, an acrylic binder can be used.

As the dispersion solvent, for example, an alcohol solvent can be used. (Second Step) Through holes are formed in the ceramic green sheet produced in the first step by mechanical processing using, for example, a punch and a die. It is preferable that the through hole has a minimum diameter of about 100 μm in order to facilitate a process of filling a metal melt or the like described later. Next, a volatile material that volatilizes at the sintering temperature of the green sheet is screen-printed on the green sheet to form a pattern similar to the conductor circuit to be formed, and at the same time, the volatile material is formed in the through hole. Embed the material.

The pattern made of the easily fugitive material has a width of 40 μm or more, preferably 70 μm or more, and practically 1 in order to facilitate the step of filling a metal melt or the like described later.
It is desirable that the thickness is 00 μm or more.

As the easily volatile material, for example, a viscous material having a composition consisting of a binder such as an acrylic binder and an ethyl cellulose binder and a solvent can be used. The viscous material is approximately 1 × 10 ⁴ to 1 × 10 ⁶ cp.
It preferably has a viscosity of s, and the viscosity can be easily adjusted by controlling the amount of the binder and the amount of the solvent.

The pattern after the screen printing retains a desired width and thickness as it is, but some sagging may occur. In such a case, an easily volatile material to which an electron beam curable type, an ultraviolet ray curable type, or a thermosetting type resin is added, is irradiated with ultraviolet ray or an electron beam before being dried after screen printing, or The pattern can be held in a desired width and thickness by slowly applying heat to accelerate the hardening of the formed pattern.

(Third Step) A desired number of the ceramic green sheets subjected to the second step are laminated and thermocompression bonded to produce a laminated body. Subsequently, this laminate is heat-treated at a desired temperature and atmosphere to evaporate the pattern made of the fusible material embedded between the green sheets of the laminate and the fusible material embedded in the through hole. Remove. As a result, a void having a shape corresponding to the pattern is formed inside the laminated body, and the through hole is hollowed. When the voids are formed and the through holes are hollowed, if carbon generated by the decomposition of the binder in the fugitive material remains inside the voids, the insulating characteristics of the manufactured multilayer circuit board may deteriorate. . Therefore, it is preferable to perform degreasing in vacuum for the purpose of completely removing the binder. The ceramic green sheet is sintered by further heat-treating the thus obtained laminate at a higher temperature. It can be seen that the voids and the through holes are partially narrowed during sintering due to grain growth of the ceramic material, but they are not completely closed. Rather, the grains grow like pillars in a part of the voids, so that the mechanical strength of the laminate can be increased.

(Fourth Step) The voids and through holes of the laminate produced in the third step are filled with a melt of at least one metal selected from gold, silver, copper and aluminum. As a filling method, a metal melt is prepared by heating the metal at a temperature equal to or higher than its melting point in a container capable of pressurizing and depressurizing, and immersing the laminate in the melt to form voids and through holes. A method of introducing the metal melt into the inside is adopted. Specifically, after the laminated body is immersed in the metal melt in the container, the pressure of the container is reduced to exhaust air remaining in the voids of the laminated body. At this time, the metal melt easily flows into the voids. However, at this stage, the metal melt is not filled in all the voids. Therefore,
After evacuation, pressure is applied to allow the metal melt to further flow into the unfilled portion of the void. The pressing force at this time cannot be unconditionally specified depending on the width and thickness of the void, but by applying a pressure of 1 × 10 ⁵ Pa, the metal melt can be filled up to every corner of the void and the through hole. After the filling, the laminate is pulled up from the metal melt and cooled. At this time, the metal melt does not leak from the opening of the void. After the cooling, the solidified material of the metal melt adheres to the surface of the laminate, but it can be easily removed by polishing the surface. By filling and cooling and solidifying the metal melt, a conductor circuit made of at least one metal selected from gold, silver, copper and aluminum is embedded in the void, and the metal is embedded in the through hole.

As another metal filling method, gold,
A slurry containing at least one metal powder selected from silver, copper and aluminum, or a slurry containing a substance that is converted to gold, silver, copper or aluminum by heat treatment at high temperature is used as voids and through holes of the laminate. It is possible to employ a method in which the resin is filled at room temperature and then heat-treated at high temperature. The viscosity of the slurry can be easily controlled by the amounts of binder and solvent added. When filling the voids and through holes of the laminated body with the slurry, the voids and the through holes are evacuated from the openings of the voids and the slurry is caused to flow into the openings of the other voids and the through holes. Can be filled. As the substance whose metal is converted by the heat treatment at the high temperature, for example, an oxide, a halide, an alkoxide or an organometallic compound of the above metal can be used. After the filling is completed by such a method, the binder is removed by heating in a non-oxidizing atmosphere, for example, in a nitrogen gas stream, and then heat treatment is performed at a predetermined temperature in the non-oxidizing atmosphere so that the voids are filled with gold. , A conductor circuit made of at least one metal selected from silver, copper and aluminum is buried, and a via fill made of the metal is formed in the through hole.

When the heat treatment is carried out after the metal melt is press-fitted or the slurry is poured at room temperature as described above, it is possible to carry out the treatment at a temperature of usually about 1000 ° C. When a ceramic multilayer circuit board is manufactured by simultaneous sintering using the conductor material such as gold described in the present invention by the conventional method, the ceramic material or the sintering aid added to the metal reacts with the conductor circuit. Causes a problem that the electric resistance of is high. In the present invention, since the ceramic laminated body can be processed at a relatively low temperature after being formed by sintering, it is possible to suppress the reaction between the ceramic material or the sintering aid added thereto and the metal (conductor circuit). .

Finally, if necessary, the surface of the laminate is subjected to plating, pin formation, etc. to form a conductor circuit made of at least one metal selected from gold, silver, copper and aluminum and a via fill made of the metal. A ceramic multilayer circuit board having the same is manufactured.

As described above, according to the present invention, the thermal conductivity is high by separating the step of stacking and sintering the ceramic green sheets from the step of forming the conductor circuit,
It has a dense ceramic insulating layer with high mechanical strength and has a low resistance conductor circuit such as gold, silver, copper or aluminum, and further has defects such as peeling, oxidation and disconnection in the conductor circuit. It is possible to manufacture a ceramic multilayer circuit board having a small number of good characteristics, and thus realize high-density mounting of elements such as LSI and high-speed signal propagation.

[0023]

EXAMPLES Examples of the present invention will be described in detail below. Example 1 5% by weight of Y ₂ O ₃ powder was added as a sintering aid to AlN powder having an average particle size of 0.6 μm by the reduction nitriding method, and wet mixed in n-butanol for 48 hours using a ball mill.
This mixed powder was dispersed in an alcohol solvent together with a polyacrylate binder to prepare a slurry of about 4000 cps. Subsequently, a green sheet having a thickness of about 200 μm was formed on the organic film by casting the slurry on the organic film. Subsequently, a plurality of through holes were formed at predetermined positions of each green sheet by using a punch and a die.

Next, 20% by weight of acrylic binder,
Plasticizer 10% by weight, solvent 70% by weight in a ball mill 24
After mixing for an hour, vacuum deaeration was performed to prepare a viscous material.
Subsequently, the viscous material was screen-printed on the surface of each green sheet to form a predetermined conductor circuit pattern, and the through-hole was filled. Subsequently, a plurality of green sheets having the above pattern formed thereon were laminated so that predetermined through holes were aligned with each other, subjected to hot pressing, and then subjected to contour processing for cutting the end portions.

Next, the obtained laminated body was vacuumed at about 500 ° C. to degrease (debinder) it. The degreased laminate was sintered at 1800 ° C. for 6 hours in a nitrogen atmosphere. The obtained sintered body is shown in FIG. In FIG. 1, 1 is an AlN sintered body, 2 is a through hole from which the viscous material has been volatilized and removed,
Reference numeral 3 is a conductor-circuit-shaped void formed by volatilizing and removing the viscous material pattern formed between the green sheets. Although a narrowed portion was found in a part of the through hole 2 and the void 3 inside the AlN sintered body 1, it was formed in a substantially complete shape.

Next, metallic copper is placed in a container capable of pressurizing and depressurizing, which is exposed to a nitrogen atmosphere, and a copper melt is prepared by maintaining the temperature at 1100 ° C. Then, the copper melt is baked. Was soaked. After vacuuming and degassing, 7 × 10 ⁴
The copper melt was filled into the voids and through holes of the sintered body by pressurizing to Pa and holding for 30 minutes. After introducing nitrogen, the sintered body was pulled up and naturally cooled to room temperature. Copper adhered to the surface of the taken out sintered body, but could be removed by polishing each surface by about 10 μm. Subsequently, a copper conductor circuit was formed on the surface of the sintered body by a thick film method, and then a Ni—Au layer was deposited on the conductor circuit by electrolytic plating.

When several parts of the obtained AlN multilayer circuit board were cut and the inside was observed, good conductor circuits without defects were formed. In addition, in observing the appearance of the multilayer circuit board, no warpage or deformation was observed.

Further, A of the obtained AlN multilayer circuit board
The 1N sintered body has a resistivity of 10 ¹¹ Ω · cm or more, a relative dielectric constant of 8.7, a dielectric loss of 10 ⁻³ or less (both at 1 MHz), and a thermal conductivity of 160 W / m · K. Met. Moreover, the resistivity of the conductor circuit and the via fill was measured, and it was an extremely low value of 3 × 10 ⁻⁶ Ω · cm.

Example 2 An AlN multilayer sintered body having conductor circuit-shaped voids and through holes therein was produced by the same method as in Example 1. While evacuating from one opening of the void of this sintered body, a slurry of polyvinyl butyral, phthalic acid ester, butanol, trichlorethylene and silver powder was poured into the opening of the other void. Subsequently, after confirming that the slurry was sufficiently filled in the voids of the sintered body, it was dried. Subsequently, the sintered body was placed in an electric furnace and heat-treated in a nitrogen stream at 750 ° C. for 2 hours.

The obtained AlN multi-layer circuit board had no warp or deformation in its appearance and had a silver conductor circuit having no defect inside. Further, various characteristics of the sintered body of the multilayer circuit board were similar to those of Example 1.

Example 3 20 parts by weight of an acrylic electron beam curable resin as a viscous material, 10 parts by weight of an acrylic binder, 10 parts by weight of a plasticizer, and a solvent 70
Using 20% by weight added to the mixed part consisting of parts by weight, the viscous material is printed on the surface of the green sheet and in the through holes, and then irradiated with an electron beam for 5 minutes. An AlN multilayer circuit board was manufactured in the same manner as in Example 1 except that the melt was used.

The obtained AlN multilayer circuit board had no warp or deformation in its appearance and had an aluminum conductor circuit formed therein without any defect. Example 4 96% by weight of an alumina powder having an average particle diameter of 0.8 μm and the balance of silica powder, magnesia powder and calcia powder were mixed in n-butanol using a ball mill.
Wet mixed for 8 hours. Disperse this mixed powder in an alcohol solvent together with a polyacrylate binder to obtain about 4
A 000 cps slurry was prepared. Subsequently, a green sheet having a thickness of about 200 μm was formed on the organic film by casting the slurry on the organic film. Subsequently, a plurality of through holes were formed at predetermined positions of each green sheet by using a punch and a die.

Then, in the same manner as in Example 1, a viscous material was printed on the surface of each of the green sheets by screen printing to form a predetermined conductor circuit pattern, and was filled in the through holes. Subsequently, a plurality of green sheets having the above pattern formed thereon were laminated so that predetermined through holes were aligned with each other, subjected to hot pressing, and then subjected to contour processing for cutting the end portions.

Then, the obtained laminated body is vacuumed to degrease it (de-binder), and then, in air at 1600 ° C. for 6 hours.
By sintering for a time, a dense alumina sintered body having voids inside was obtained. Then, a gold melt was poured into the voids of the sintered body in the same manner as in Example 1 to fill the conductor circuit and the through holes with gold.

In the obtained multilayer circuit board, the alumina sintered body had a thermal conductivity of 15 W / m · K, the conductor circuit had a resistivity of 10 ¹¹ Ω · cm or more, and a relative dielectric constant of 10 (value at 1 MHz. )Met.

Example 5 An alumina sintered body having voids inside was produced by the same method as in Example 4, and the voids of the sintered body were filled with a slurry containing silver oxide in the same manner as in Example 2. Further, an alumina multilayer circuit board was manufactured by further performing heat treatment at 750 ° C. for 2 hours in a nitrogen stream.

The obtained multilayer circuit board was cut and the inside was observed. As a result, the silver oxide filled in the voids was changed to white silver. No defects such as cracks were found around the silver conductor circuit. The resistivity of the conductor circuit was about 5 × 10 ⁻⁶ Ω · cm.

Example 6 A green sheet was prepared in the same manner as in Example 1 by using a mixed powder composed of 80% by weight of mullite having an average particle diameter of 2 μm, 14% by weight of alumina, 5% by weight of silica and 1% by weight of magnesia. A through hole was formed by machining. A viscous material was prepared by adding 15% by weight of a phenolic thermosetting resin to a mixed part composed of 20 parts by weight of an acrylic binder, 10 parts by weight of a plasticizer and 70 parts by weight of a solvent, and the viscous material was prepared as described above. After forming a conductor circuit pattern on the surface of the green sheet by a printing method and filling the through hole, the viscous material filled in the pattern and the through hole was cured by holding at 100 ° C. for 5 minutes. The green sheets were laminated in the same manner as in Example 1 and then degreased. Subsequently, the laminated body after degreasing is placed in the air,
It was sintered at 1600 ° C. for 1 hour to obtain a mullite-based sintered body having voids in the shape of a conductor circuit inside. Subsequently, after the slurry containing aluminum powder was filled in the voids of the sintered body by the same method as in Example 2, 50 in a nitrogen atmosphere.
It heat-processed at 0 degreeC for 1 hour.

No warpage or deformation was observed in the obtained mullite multilayer circuit board. Example 7 A green sheet was prepared in the same manner as in Example 1 using a mixed powder prepared by adding 10% by weight of Y ₂ O ₃ powder and 4% by weight of alumina powder as a sintering aid to silicon nitride having an average particle size of 1 μm. And a through hole was formed by machining. 20% by weight of an ultraviolet-sensitive polyimide resin was added to a mixed part composed of polyvinyl butyral, phthalic acid ester, butanol, and trichloroethylene to prepare a viscous material, and the viscous material was printed on the surface of the green sheet by a printing method. After forming a conductor circuit pattern and filling the through holes, ultraviolet rays were irradiated to cure the viscous material filled in the patterns and the through holes. The green sheets were laminated in the same manner as in Example 1 and then degreased. Subsequently, the degreased laminated body was sintered in a nitrogen atmosphere at 1800 ° C. for 6 hours to obtain a silicon nitride sintered body having conductor circuit-shaped voids inside. Subsequently, a copper melt was poured into the voids of the sintered body in the same manner as in Example 1 and cooled.

No warpage or deformation was found in the obtained silicon nitride multilayer circuit board. In addition, when the conductor circuit inside was observed, defects such as voids were not recognized. Further, the silicon nitride sintered body of the multilayer circuit board has a thermal conductivity of 1
The conductive circuit had a resistivity of 10 ¹¹ Ω · cm or more and a relative dielectric constant of 10 (value at 1 MHz).

[0041]

As described in detail above, according to the present invention, a base material which maintains the high thermal conductivity inherent in the ceramic material and a conductor circuit having a low electric resistance with little problems such as signal propagation delay are provided. Further, it is possible to provide a method for manufacturing a ceramic multilayer circuit board having sufficiently high mechanical strength.

[Brief description of drawings]

FIG. 1 is a partially cutaway perspective view showing an AlN sintered body before forming a conductor circuit, which is manufactured in Example 1 of the present invention.

[Explanation of symbols]

 1 ... AlN sintered body, 2 ... through hole, 3 ... void.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Katsuyoshi Oishi 1 Komukai Toshiba-cho, Sachi-ku, Kawasaki-shi, Kanagawa Toshiba Research & Development Center (72) Inventor Fumio Ueno Komukai, Kawasaki-shi, Kanagawa Toshiba Town No. 1 Inside Toshiba Research and Development Center

Claims (2)

[Claims] 1. A step of preparing a shellac slurry by dispersing ceramic powder in a desired solvent, forming the slurry into a sheet, and drying the ceramic green sheet to form a ceramic green sheet, and after forming a through hole in the green sheet, Embedding a volatile material that volatilizes at the sintering temperature of the green sheet in the through hole of the green sheet and forming a conductor circuit-shaped pattern made of the volatile material on the surface of the sheet, and the green sheet After laminating a plurality of sheets, sintering and volatilizing and removing the volatile material, and a melt of at least one metal selected from gold, silver, copper or aluminum in the void formed by the sintering. And forming a conductor circuit by burying the metal and burying the metal in the through hole. And a method for manufacturing a ceramic multilayer circuit board. 2. A step of preparing a ceramic slurry by dispersing ceramic powder in a desired solvent, forming the slurry into a sheet, and drying the slurry to produce a ceramic green sheet; and after forming a through hole in the green sheet, Embedding a volatile material that volatilizes at the sintering temperature of the green sheet in the through hole of the green sheet and forming a conductor circuit-shaped pattern made of the volatile material on the surface of the sheet, and the green sheet After laminating a plurality of sheets, by sintering and volatilizing and removing the easily volatile material, by a slurry containing gold, silver, copper or aluminum in the voids formed by the sintering, or by heat treatment at a high temperature After filling a slurry containing a substance that is converted to gold, silver, copper or aluminum, heat treatment at high temperature A step of forming a conductive circuit by burying the metal and burying the metal in the through hole.