JP2803755B2 - Multilayer electronic circuit board - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a multilayer electronic circuit board having excellent heat dissipation and reliability, having a film-like element such as a conductive circuit formed on a surface thereof.

(Prior art)

In recent years, various electronic circuit boards have been known and put into practical use. For example, glass-epoxy composites,
2. Description of the Related Art Electronic circuit boards using alumina sintered bodies, mullite sintered bodies, and the like as substrate materials have been proposed and used. As one method for promoting high integration, a mounting method of directly mounting a silicon integrated circuit or the like on a substrate is being studied.

However, since the glass-epoxy composite has a significantly different coefficient of thermal expansion from the silicon integrated circuit, the silicon integrated circuit that can be directly mounted on the substrate is limited to an extremely small one. In addition, a substrate made of a glass-epoxy composite alone is liable to change its dimensions in a circuit forming process, and therefore is difficult to apply particularly to a substrate requiring a fine and precise circuit.

In addition, since these substrates have a large proportion of resin, their thermal conductivity is as low as 0.5 w / m · K at most, and they have a sufficient heat dissipation capacity against heat generated by recent high-density silicon integrated circuits and resistance components. Do not have.

Further, alumina-based sintered bodies and mullite-based sintered bodies have high hardness and are inferior in machinability. For this reason, for example, when machining such as providing a through hole or the like is required, a method of firing after processing at the stage of a formed body is performed. However, it is difficult to uniformly generate shrinkage during firing, and it is particularly difficult to manufacture a product requiring high dimensional accuracy or a product having a large size.

To address these problems, Japanese Patent Laid-Open No.
No. 7190 or JP-A-64-82689 proposes a substrate in which the pores of a porous ceramic sintered body are impregnated with a resin.

This substrate is adapted to the thermal expansion of a component to be mounted, for example, a silicon integrated circuit or the like by changing the porosity of the ceramic in various ways, and has low expansion and excellent dimensional stability. In addition, machining is easy, and it is possible to cope with an increase in size and weight.

On the other hand, in recent years, a multilayer electronic circuit board is often used by stacking a plurality of electronic circuit boards for high integration.

Further, instead of chip components such as chip resistors and capacitors, an electronic circuit board having a film-like element in which these elements are formed on a circuit in the form of a film has been developed.

As described above, by forming a film-like conductive circuit, a resistor, a capacitor, and other film-like elements, the size and weight of the electronic circuit board can be reduced.

[Problem to be solved]

However, an electronic circuit board in which a film element is formed on the above-described porous ceramic-resin impregnated substrate has poor reliability in use.

That is, in the above-described resin-impregnated porous ceramic substrate, the film-like element formed on the surface is formed on the resin.
The behavior of the resin significantly affects the film-shaped element. For example, there is a major drawback in that the initial characteristics, for example, the resistance value and the capacitance of the film-like element in contact with the resin greatly fluctuate due to high humidity and high temperature.

In a multilayer electronic circuit board formed by laminating a plurality of electronic circuit boards, it is necessary to efficiently release the heat generated from the electronic circuit of each electronic circuit board to the outside. In particular, as the number of layers increases, it becomes more difficult for heat generated from the electronic circuit of each substrate to be released to the outside.

In view of the above-mentioned conventional problems, the present invention provides a highly reliable multi-layered film having excellent resistance to high humidity, high temperature, and heat radiation by taking advantage of the above-mentioned resin-impregnated porous ceramic sintered substrate. It is intended to provide an electronic circuit board.

[Solutions to solve the problem]

The present invention relates to an electronic circuit board in which a film-like conductive circuit, a resistor, a capacitor or the like is directly formed on a surface of a porous ceramic sintered body, and a radiator is bonded to the porous ceramic sintered body. Then, the electronic circuit boards are laminated and bonded together by interposing an inorganic or metal porous intermediate layer between the electronic circuit boards, and then the resin is filled into the pores of the porous ceramic sintered body. A multilayer electronic circuit board characterized in that:

The most remarkable point in the present invention is that a plurality of electronic circuit boards having a film element directly formed on the surface of a porous ceramic sintered body and a radiator bonded to the sintered body are used. Laminating and bonding are performed with a porous intermediate layer interposed therebetween, and then the resin is impregnated in the pores of the sintered body.

That is, in the electronic circuit board of the present invention, a film-like element such as a conductive circuit enters the pores and irregularities on the surface of the porous ceramic sintered body and comes into direct contact with the wedge shape. Further, the heat radiator also enters the pores and unevenness in a wedge shape directly or through an adhesive layer, and is closely adhered. On the other hand, the pores other than the film-shaped element forming portion are filled with resin after the electronic circuit board is laminated.

As a method for forming a film-like element such as a conductive circuit on the surface of a porous ceramic sintered body, first, a paste containing particles for forming the film-like element is applied to a ceramic formed body by a method such as printing. Then, there is a method of firing the formed ceramic body at a temperature at which a sintered body is formed.

Another method is to first prepare a porous ceramic sintered body, apply the paste to the surface of the sintered body, and then bake the paste.

Further, there is a method in which a portion other than a circuit is masked on the surface of the porous ceramic sintered body, a film-like element such as a conductive circuit is formed by vapor deposition, sputtering or the like, and then the mask is removed.

In any method, it is important that the porous ceramic sintered body and the film element are in direct contact with each other.

As described above, since the porous ceramic and the membrane element are in direct contact with each other, the membrane element is extremely stable against environmental changes such as temperature and humidity.

Here, the film element refers to an electronic component formed in a film on a substrate, such as a conductive circuit, a film resistor, and a film capacitor as described above. Further, these film elements are formed on one side or both sides of the electronic circuit board.

Examples of the radiator include a ceramic sintered body, diamond, and a metal film as described later. Further, these heat radiators are bonded to the porous ceramic sintered body directly or via an adhesive layer.

That is, as a method of bonding the heat radiator directly to the surface of the porous ceramic sintered body, an opening is formed in the formed ceramic body by drilling or punching, and the prepared heat radiator is attached to the opening. And then sintering them to heat-tighten the radiator and fit. Further, there is a method of joining while applying pressure by a hot press or the like. Examples of the radiator include ceramic sinters such as alumina, silicon carbide, aluminum nitride, and beryllium oxide, which are ceramic sinters having high heat dissipation.

As another method, there is a method of forming a film-shaped heat radiator such as diamond, silicon carbide, or aluminum nitride on the surface of the porous ceramic sintered body by CVD or the like. Further, there is a method of forming a radiator of various metal or inorganic films by thermal spraying, vapor deposition, or sputtering.

On the other hand, as an adhesive for bonding the porous ceramic sintered body and the heat radiator, there is an adhesive of a metal and / or an inorganic material.

As a bonding method using such an adhesive, a powder of the adhesive is applied to a ceramic sintered body in advance, and the heat radiator is placed in contact with the ceramic sintered body, and then heated to a temperature at which the adhesive powder melts. There is a way. At this time, it is better that the thermal expansion coefficient of the porous ceramic sintered body and the heat radiator are close to each other, but if not, the heat radiator is used as a small piece to reduce the difference in thermal expansion. Alternatively, the coefficient of thermal expansion is adjusted by changing the ratio of the metal and the inorganic material powder, or the layer of the metal and / or the inorganic material is changed in several stages to form an intermediate layer between the porous ceramic sintered body and the radiator. It is preferred that the thermal expansion coefficient is set to a suitable value and the thermal stress of both is relaxed.

The adhesive layer made of the metal and / or inorganic material is preferably as dense as possible. The reason for this is to exhibit excellent heat dissipation. For this purpose, the porosity is preferably 30% or less.

The material of the porous ceramic sintered body is as follows.
Main component is at least one of cordierite, alumina, aluminum nitride, mullite, magnesium titanate, aluminum titanate, silicon dioxide, lead oxide, zinc oxide, beryllium oxide, tin oxide, barium oxide, magnesium oxide, and calcium oxide And the like. Among them, cordierite is a preferable material because its coefficient of thermal expansion is close to that of silicon integrated circuits.

In the present invention, the porous ceramic sintered body preferably has an average pore diameter of 0.2 μm or more. The reason is that if the average pore diameter is smaller than 0.2 μm, the adhesion between the heat radiator and the porous ceramic sintered body is reduced. That is, the wedge effect for improving the adhesion is reduced.

In the present invention, the porosity is preferably 5% (volume ratio) or more. The reason for this is that if the porosity is smaller than 5%, the contact area between the heat radiator and the porous ceramic sintered body becomes small, and the adhesive strength decreases.

In the electronic circuit board provided with the heat radiator and the film element as described above, a plurality of the heat radiators and the film elements are stacked one on top of another, and the space therebetween is joined by the porous intermediate layer to form a multilayer body. Pores of ceramic sintered body are impregnated with resin,
It is a multilayer electronic circuit board (see FIG. 1).

That is, the laminate is formed by adhering the respective substrates with a porous intermediate layer interposed between the electronic circuit substrates.

As the porous intermediate layer, an inorganic or metal porous material such as glass is used. As such a porous intermediate layer,
Glass with a relatively low melting point, or ceramic, aluminum, gold, silver, copper, tungsten, or the like is used. In order to form a porous material as described above, for example, a method is used in which powdery particles are applied to the substrate surface, the substrates are superposed, and then heated and sintered at a temperature equal to or lower than the melting point. The reason why the intermediate layer is made porous is to facilitate impregnation of the resin into the porous sintered body substrate in a later step.

The porosity of the porous intermediate layer is preferably from 5 to 50% from the viewpoint of preventing a decrease in thermal conductivity and relaxing stress caused by a difference in thermal expansion.

Further, such a porous intermediate layer can also be formed by laminating formed forms of an electronic circuit board and firing them at a high temperature. That is, since each electronic circuit board is made of ceramic, the two electronic circuit boards are sintered by this firing to form a porous intermediate layer.

When a metal is used as the porous intermediate layer, and when the film-shaped element is on the substrate surface facing the intermediate layer, an electric insulating layer is interposed between the two.

Examples of the resin to be impregnated in the above sintered body include epoxy resin, polyimide resin, triazine resin, polybalavanic acid resin, polyamide imide resin, silicon resin, epoxy silicon resin, acrylic resin, methacrylic resin, anilic acid resin, and phenol resin. , Urethane-based resins, furan-based resins, and fluororesins.

As a method of impregnating the porous sintered body with the resin, there is a method in which the resin is heated and melted, and the laminated body of the electronic circuit board is immersed therein. Further, there are a method of impregnating a resin by dissolving it in a solvent, and a method of impregnating a resin in a monomer state and then polymerizing the resin. By this impregnation, the pores of the porous intermediate layer are also impregnated with the resin.

The bonding of the laminate is performed by pressure baking, baking of a porous intermediate layer, or the like, as shown in the examples.

Further, an insulating layer may be provided on the surface of the multilayer electronic circuit board obtained as described above, and a conductor layer may be further formed thereon (see FIG. 4).

As the insulating layer, a resin or a composite material of a resin and an inorganic material is used. As the resin, an epoxy resin, a phenol resin, a polyimide resin, or the like is used. As the composite material of the resin and the inorganic material, epoxy resin, glass fiber, polyimide resin containing glass particles, or the like is used.

The conductor layer is an electronic circuit conductor. As a method of forming the conductor layer, for example, a method of laminating a metal foil,
There are a vapor deposition method and a sputtering method.

The multilayer electronic circuit board formed as described above can be formed with a through hole after filling with a resin, and can be connected to each other by electroless copper plating or the like.

[Action and effect]

In the multilayer electronic circuit board of the present invention, since each electronic circuit board directly forms a film element on the surface of the porous ceramic sintered body, the film element is wedges between the particles of the sintered body. It is tightly adhered and bonded in a shape. Therefore, the film element does not peel off. Further, since the pores are filled with the resin in the portion where the film-shaped element is not formed, it is excellent in high humidity resistance and high temperature resistance.

In addition, since the heat radiator is also closely adhered to the porous ceramic sintered body, the radiator is firmly connected in a wedge shape between the particles of the sintered body. Therefore, the heat generated from the film-shaped element on the substrate can be efficiently transferred to the radiator.

In addition, by filling the resin, the strength of the entire substrate is increased, and the substrate is hardly cracked, and at the same time, machining is facilitated, and processing defects such as chipping and chipping can be prevented. It is also effective in preventing gas permeation and reducing the influence from the use environment.

Further, the stacked electronic circuit boards are bonded by the porous intermediate layer. Since the porous intermediate layer is made of an inorganic material or a metal, it has good heat conductivity. Therefore, the heat generated in each electronic circuit board is efficiently radiated to the outside also from the porous intermediate layer.

Also, because of such excellent heat dissipation, the multilayer electronic circuit board of the present invention can mount a large number of silicon integrated circuits and high resistance elements which generate a large amount of heat, and can cope with miniaturization and high integration. Can be. It is also useful as an electronic circuit board for a device that generates a large amount of heat, such as a power supply module or an infrared ray generator.

Therefore, according to the present invention, a highly reliable multilayer electronic circuit board excellent in high humidity resistance, high temperature resistance, heat dissipation, and machinability can be provided.

〔Example〕

First Embodiment A multilayer electronic circuit board according to an embodiment of the present invention will be described with reference to FIGS.

As shown in FIG. 1, the multilayer electronic circuit board has electronic circuit boards 51 and 53 laminated on and under a central electronic circuit board 52.
Between them, a porous intermediate layer 6 is interposed and integrally bonded, and furthermore, a conductor layer 35 is formed on the upper and lower surfaces via an insulating layer 3 to form an eight-layer circuit. Each electronic circuit board is
It has a radiator as shown below.

As shown in FIG. 2, the electronic circuit board 51 has a film-shaped conductive circuit 512 and a film-shaped resistor 513 on the front surface of the porous ceramic sintered body 11 as a substrate, and similarly on the back surface. This is a film-shaped element formed in close contact. A metal radiator 41 is bonded to the porous ceramic sintered body 11 via a glass adhesive 48 in a recess 16 formed by counterbore processing on the back surface of the porous ceramic sintered body 11. The radiator 42 is joined. Further, a metal radiator 43 is joined to the front surface of the porous ceramic sintered body 11 via a metal adhesive 49.

As shown in FIG. 3, the close contact state of the film-like element is formed by a film-like conductive circuit 512, a concave-convex surface between a large number of ceramic particles 10 constituting the porous ceramic sintered body 11.
The lower surface of the film-shaped resistor 513 is in a wedge-shaped state.

As shown in FIG. 4, the adhesive 48 for bonding the metal heat radiator 41 is also tightly bonded between the ceramic particles 10 of the porous ceramic sintered body 11 in a wedge shape.

In addition, as shown in FIG.
11 between the opening 17 and the ceramic radiator 42.
Are tightly joined in a wedge-like manner between the ceramic particles 10 in the opening 17.

Further, as shown in FIG. 6, the adhesive 49 is bonded between the ceramic particles 10 in a wedge-like manner between the adhesive 49 for bonding the metal radiator 43 and the porous ceramic sintered body 11. ing.

Further, inside the porous ceramic sintered body 11,
The pores formed between the ceramic particles 10 are filled with a resin 14 impregnated after lamination (see FIG. 3). Resins are similarly impregnated in the pores of the porous intermediate layer 6.

The other electronic circuit boards 52 and 53 are the same as the above-mentioned electronic circuit board 51. That is, each of the above electronic circuit boards
51, 52, 53 are film-shaped conductive circuits 512, 522, 532, and film-shaped resistors 51
3,523,533 are formed on the surface. Further, each electronic circuit board has a radiator as described above. Further, between the film-like conductive circuits and the film-like resistors in the electronic circuit boards 51, 52 and 53, and further between the conductor layer 35 on the outermost surface, the board-to-board conduction through-hole 55, the through-hole 57 in the board, and the like. Are provided respectively.

A porous intermediate layer 6 is interposed between the electronic circuit boards 51, 52, 53. The porous intermediate layer is made of a ceramic material.

In addition, since the multilayer electronic circuit board is immersed in a molten resin and impregnated with the resin after forming the laminate, the surface is in a state of being covered with the resin.

Thus, the multilayer electronic circuit board according to the present embodiment has a film-like element and a heat radiator bonded to each of the electronic circuit boards constituting the multilayer electronic circuit board with good adhesion. A good porous intermediate layer is located. The pores of the porous ceramic sintered body are impregnated with a resin.
Therefore, the multilayer electronic circuit board is excellent in high humidity resistance, high temperature resistance, heat dissipation, and machinability, and has high reliability.

Second Embodiment A multilayer electronic circuit board (see FIG. 1) having an eight-layer circuit similar to that shown in the first embodiment was manufactured and tested.

The multilayer electronic circuit board was manufactured by first preparing an electronic circuit board A and an electronic circuit board B, and then laminating the electronic circuit boards B and B on and under the electronic circuit board A.

That is, the average particle size is 1.
2 parts by weight of polyvinyl alcohol, 1 part by weight of polyethylene glycol, 0.5 parts by weight of stearic acid and 100 parts by weight of water were mixed with 100 parts by weight of cordierite powder of 8 μm, mixed in a ball mill for 3 hours, and spray-dried. .

Take an appropriate amount of the dried product and use a metal stamping die for 1.0t.
It was molded under a pressure of / cm ² to obtain a ceramic forming body having a size of 220 mm × 250 mm × 1.2 mm and a density of 1.5 g / cm ³ (60 vol%).

The resulting feature was perforated and provided with a 20 × 20 mm opening.

On the other hand, 100 parts by weight of an alumina powder having an average particle size of 0.30 μm, 12 parts by weight of a polyacrylate, 1 part by weight of a polyester dispersant, 2 parts by weight of dibutyl phthalate, and After mixing 50 parts by weight of ethyl and mixing in a ball mill for 3 hours, a sheet was formed to obtain a formed product. The green body was fired at 1650 ° C. in air.

As a result, a dense alumina sintered body having a density of 4.02 g / cm ³ and a porosity of 0.2% was obtained. After that, it is cut to 19.2 x 19.2 mm and used as a heat radiator 42, and the opening of the cordierite forming body
17 (see FIG. 2).

Next, the cordierite compact is placed in air at 1400 ° C.
To form a porous cordierite sintered body.

The obtained porous cordierite sintered body has a thickness of 0.25 m.
m, density 1.8 g / cm ³ , porosity 30%, and average pore diameter 3.2 μm.

Also, the joint strength between the heat radiator made of the dense alumina sintered body and the porous cordierite sintered body was extremely strong, 8.9 kg / mm ² .

Next, on the surface of this porous cordierite sintered body,
Viscosity containing 48% silver-palladium particles with an average particle size of 11μm
An 80 Pa · s paste was printed on a 325 mesh screen to form a conductive circuit. Next, average particle size 16μm
A paste having a viscosity of 170 Pa · s containing 38% of ruthenium oxide particles was printed on a 325-mesh screen to form a thin-film resistor on the conductor.

 Thus, the electronic circuit board A was manufactured.

Next, in order to fabricate the electronic circuit board B, the average particle size was set at 0.
For 50 parts by weight of 68 μm alumina powder, the average particle size is 0.
50 parts by weight of 32 μm alumina powder, 12 parts by weight of polyacrylate, 1 part by weight of polyester dispersant, 2 parts by weight of dibutyl phthalate, and 50 parts by weight of ethyl acetate were mixed, mixed in a ball mill for 3 hours, and formed into a sheet. .

A counterbore of 20 × 20mm and 0.2mm depth was made on this generated form.
A recess 16 (see FIG. 2) was formed.

Next, this was fired in air at 1550 ° C. for 1 hour to obtain a porous alumina sintered body.

The sintered body had a thickness of 0.45 mm, a density of 2.9 g / cm ² , a porosity of 25%,
The average pore diameter was 0.29 μm.

The same silver-palladium particles as those printed on the surface of the porous cordierite sintered body were applied to the surface of the porous alumina sintered body to form a circuit. Next, the average particle size
170Pa · s containing 38% of ruthenium oxide particles of μm
Is printed on a 325 mesh screen.
A thin film resistor was formed on the conductor.

Next, the counterbore recess 16 of the porous alumina sintered body was used.
The average particle size of the K ₂ O-SiO ₂ -PbO system as an adhesive was 13 μm.
Glass powder with a thickness of 30 μm, and radiator 41
A 42 alloy plate (nickel-iron alloy) was placed, heated, and fixed (see FIG. 2). The surface of the 42 alloy plate was roughened with chromic acid.

 Thus, the electronic circuit board B was manufactured.

Next, an electronic circuit board A (second layer) made of the porous cordierite sintered body and an electronic circuit board B (first and third layers) made of the porous alumina sintered body are shown in FIG. In three layers.

At this time, in order to form the porous intermediate layer 6 (see FIG. 1), an Al ₂ O ₃ —SiO ₂ —TiO ₂ ceramic powder having an average particle diameter of 13 μm was applied to each layer to a thickness of about 100 μm, and each sintered body was formed. Was stuck. This was baked at 820 ° C. in air. The typical resistance value at this time was 350Ω / □.

As a result, the adhesion strength between the heat radiator bonded to the porous alumina sintered bodies of the first and third layers via glass and the porous alumina sintered body was 4.3 kg / mm ² , and the adhesive layer Porosity is 13
%Met.

The porous intermediate layer has an average pore diameter and porosity of 5.0μ.
m, 35% porous layer, adhesion between sintered bodies is 2.5kg / mm
² had good adhesion.

Next, to bond the heat sink, on the front and back surfaces of the laminate, first, a 2 x 2 mm square 95% Sn-5% Pb solder was formed by sputtering into 5 x 14 x 14 mm squares. Arranged. Next, a heat-dissipating copper plate of 15 mm × 15 mm and a thickness of 1 mm was mounted on the solder surface, and bonded by heating at 260 ° C. The adhesion strength was 12 kg / mm ² , and the solder was bonded with about 6% pores.

Next, a 0.05 mm BT resin-based prepreg and 18 μm copper foil were arranged on the front and back of the laminate, and vacuum pressing was performed to form two more conductive layers on the front and back.

Next, holes were drilled to the front and back and the intermediate layer with a diamond drill having a diameter of 0.40 mm, and electroless copper plating was performed in a similar manner to 15 μm to establish conduction, and then the front and back conductor layers were etched to form a circuit.

Next, a two-component epoxy resin was impregnated and cured to obtain a multilayer electronic circuit board. This impregnation was performed by placing the substrate under vacuum, impregnating the defoamed resin under vacuum, and then thermally curing.

The multilayer electronic circuit board thus obtained was an eight-layer circuit, and the total thickness was 1.55 mm, which was extremely thin. In addition, this multilayer electronic circuit board had an extremely high mounting density in which 35 film-like resistors and 8 capacitor elements were incorporated per cm ² .

The overall thermal conductivity of this multilayer electronic circuit board is 8w / m
-K, which was extremely excellent in heat dissipation.

For this multilayer electronic circuit board, 30 seconds at 20 ° C and 30 seconds at 260 ° C
An oil dip repetition heat resistance test of 2 seconds was performed. As a result, no defect such as disconnection, peeling between substrates or peeling of a heat radiator occurred at 500 cycles.

When the multilayer electronic circuit board was subjected to a high-temperature, high-humidity life test at 85 ° C and 85% RH for 1000 hours, the rate of change of the resistance value was extremely stable at 0.18%.

Further, in the above-mentioned multilayer electronic circuit board, more than 120,000 holes could be drilled on a board having a length of 350 mm and a width of 250 mm. Thus, the electronic circuit board of the present invention has high strength and excellent machinability.

(Comparative example)

For comparison, in the second embodiment, the radiator was not directly connected to the porous ceramic sintered body.
In addition, they were simply bonded with an impregnated resin without bonding with a metal or inorganic material adhesive. Then, a multilayer electronic circuit board similar to that of the second embodiment was manufactured. As a result, the overall thermal conductivity was 2.6 W / m · K.

Also, when no radiator is used, the overall thermal conductivity is 0.
It was 9 W / m · K. In each case, it is understood that the heat dissipation is poor as compared with the case of the second embodiment.

Further, for the sake of comparison, a porous cordierite sintered body was manufactured in the same manner as in the second embodiment, immediately impregnated with the same two-component epoxy resin, and at the same time, a copper foil was laminated on the substrate. I got Next, a circuit was formed by etching. The peel strength at this time was 1.8 kg / cm, which was low.

[Brief description of the drawings]

1 to 6 show a multilayer electronic circuit board according to a first embodiment, FIG. 1 is a sectional view thereof, FIG. 2 is a sectional view of one electronic circuit board, and FIGS. FIG. 3 is an enlarged sectional view of a main part showing a bonding state between a porous element, a radiator and a porous ceramic sintered body. 10 ... ceramic particles, 11 ... porous ceramic sintered body, 14 ... resin, 3 ... insulating layer, 35 ... conductor layer, 41, 42, 43 ... radiator, 51, 52, 53 ... Electronic circuit board, 512,522,532 …… Film conductive circuit, 513,523,533 …… Film resistor element, 6… Porous intermediate layer,

Claims (2)

(57) [Claims] An electronic circuit in which a film-like conductive circuit, a resistor, a capacitor or the like is directly formed on a surface of a porous ceramic sintered body and a radiator is bonded to the porous ceramic sintered body. A substrate is manufactured, and thereafter, the electronic circuit boards are laminated, and an inorganic or metal porous intermediate layer is interposed between the electronic circuit boards and bonded. Then, a resin is poured into the pores of the porous ceramic sintered body. A multilayer electronic circuit board characterized by being filled. 2. The multilayer electronic circuit board according to claim 1, wherein a conductive layer is formed on the surface of the multilayer electronic circuit board via an insulating layer made of a resin or a composite material of a resin and an inorganic material. Multilayer electronic circuit board.