JPH07122854A - Manufacture of laminated ceramic circuit board - Google Patents

Abstract

PURPOSE:To obtain a circuit board whose continuity reliability between internal wirings can be enhanced by surely filling a conductive paste into a through recessed part passing in the thickness direction of an insulating film. CONSTITUTION:In the manufacturing method of a laminated ceramic circuit board, the surface of a base body 15 is coated with a glass-ceramic slip material which contains a photoreactive monomer, the slip material is dried, insulating films 10a to 10e are formed, through recessed parts 30 are formed in the insulating films 10a to 10e, a conductive paste is filled into the through recessed parts 30, conductors 31 to be used as via-hole conductors and conductor films 20 to be used as internal wirings are formed, this operation is repeated sequentially, and a firing treatment is executed. Then, wall faces 30a, 30b in every through recessed part 30 are tilted in such a way that the surface of the base body whose opening area is at the lower part becomes larger than an exposed area.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a laminated ceramic circuit board which is formed by sequentially repeating coating of a glass / ceramic slip material containing a photocurable monomer, filling of via-hole conductors, and filling / printing of internal wiring. It is a thing.

[0002]

2. Description of the Related Art Generally, a ceramic circuit board is manufactured by laminating a plurality of green sheets each having a conductor serving as a via-hole conductor and a conductor film serving as internal wiring.
There is a green sheet multilayer method in which a green sheet, a conductor and a conductor film are integrally fired after forming a laminated body.

On a heat resistant substrate such as ceramic,
Conductive paste is used to form a conductor film that will become the internal wiring by screen printing, and then an insulating paste will be used to form the insulating film that will become the insulating layer so that the connection between the conductive films that will become the internal wiring is exposed. There is a printing multi-layer method in which the layers are formed by screen printing, the steps are sequentially repeated to form a laminate, and the insulating film and the conductors to be the internal wirings are integrally fired.

However, in the former green sheet multi-layer method, a through hole to be a via hole conductor is formed in each green sheet, and a conductive paste is printed and filled in the through hole. However, when the opening diameter of the through hole becomes large, Since the conductive paste cannot be stably held in the through hole and the conductor may be omitted, the opening diameter of the through hole has an upper limit. Also,
In printing and filling of this conductive paste, the green sheet is placed and printed / filled on the sheet of paper, but when separating the sheet of paper and the green sheet, the conductive paste held in the through holes is The surface of the conductor in the through hole may be dented, resulting in defective conduction between the internal wirings. Further, there is a problem that a predetermined circuit cannot be achieved without stacking the green sheets described above with high accuracy and alignment.

In the latter case, it is not necessary to form a through hole to be a via-hole conductor, but an insulating film to be an insulating layer is formed by screen printing, and the amount of insulating paste transmitted from this screen is substantially constant. , The thickness of the insulating film is always uniform. Therefore, when the internal wiring covered by the insulating film becomes complicated or the number of stacked layers increases, the surface of the uppermost insulating film that has completed printing becomes uneven due to the influence of the already stacked internal wiring, and the surface thereof becomes uneven. Even if you try to form internal wiring on the
Also, problems such as disconnection will occur.

As a method for solving both of these problems, the present inventors firstly applied (1) a glass / ceramic slip material containing a photocurable monomer to the surface of a substrate and dried it. An insulating film is formed, and (2) the surface of the insulating film excluding a position to be a via-hole conductor is exposed and developed to form a through hole exposing the surface of the substrate, (3)
The conductive paste is filled in the through hole to form a conductor serving as a via-hole conductor and a conductive paste is printed on the surface of the insulating film to form a conductor film serving as internal wiring. ), A multilayer ceramic circuit board is proposed, which is obtained by sequentially repeating the steps (1) and (2) and then performing a firing process.

The above-mentioned "through hole" is expressed as a through hole because it penetrates the insulating film per layer, but in reality,
Since the surface of the substrate is exposed from the opening on the lower side of the through hole and has a “concave” shape as a whole, in order to distinguish it from the through hole of the green sheet multi-layer system, it will be referred to as “through concave” below. Express. Also, for convenience of the above method,
It is called a lamination method by applying slip materials.

In the laminating method by applying the slip material, since the application of the glass / ceramic slip material in the step (1) is applied by a blade or the like,
Since the surface of the insulating film applied as the uppermost layer is always uniform regardless of the structure of the internal wiring and the number of laminated layers, the internal wiring can be formed on the surface of the insulating film with high reliability thereafter.

Further, since the through-hole concave portion which becomes the via-hole conductor and penetrates through the thickness of the insulating film formed by coating in the uppermost layer in the step (2) is formed by the exposure / development process, it has a different opening shape depending on the purpose. The through recesses can be collectively formed, that is, a via hole conductor having an optimum shape can be achieved in consideration of currents such as a signal current, a power supply current and a ground current flowing in the via hole conductor.

Further, the alignment of the connection between the via-hole conductor and the internal wiring is determined by the exposure process for forming the penetrating recess which becomes the via-hole conductor, which is the step (2). Since the positioning of the processing is easy and highly accurate, the positional deviation is unlikely to occur as a whole, and it is not particularly necessary to perform the precise positioning as in the green sheet multilayer method.

Therefore, the manufacturing method is relatively simple, the internal wiring is not broken, and the connection reliability between the internal wiring and the via-hole conductor is improved.

[0012]

However, in the above-mentioned laminated ceramic circuit board, formation of a conductor serving as a via-hole conductor is very important.

The conductor to be the via-hole conductor has a low conductor resistance and is stable for the first time when the conductive paste is stably filled without generation of bubbles inside the through recess formed in the insulating film.
In addition, the connection reliability is high. That is, while filling the conductive paste from the opening on the surface side of the through recess, at the same time,
It is important to completely eliminate the air inside it.

If air bubbles are generated in the conductor filled in the through recess, conduction failure may occur, or the via hole conductor may expand due to expansion during firing, resulting in cracks in the via-hole conductor.

On the other hand, since the through holes in the green sheet multi-layer system have openings on both main surfaces of the sheet, there is a problem that the conductor is taken away as described above, but bubbles in the through holes are present. Can be filled without.

The present invention has been devised in view of the above-mentioned problems, and an object thereof is a multilayer ceramic in which a conductive paste can be reliably filled in a through recess penetrating the insulating film in the thickness direction. A method of manufacturing a circuit board is provided.

[0017]

The present invention comprises: (1) a step of applying a glass / ceramic slip material containing a photocurable monomer on a surface of a substrate and drying the slip material to form an insulating film; ) A step of forming a through recess in the insulating film by selective exposure / development processing, and (3) a conductor and an inside which are printed and filled with a conductive paste on the surface of the insulating film and in the through recess to form a via hole conductor. A laminate type in which a step of forming a conductor film to be wiring and (4) the steps (1) to (3) are sequentially repeated, and then the insulating film, the conductor film and the conductor are integrally fired. A method of manufacturing a ceramic circuit board, wherein the wall surface of the through recess is inclined so that the opening area on the upper side is large and the opening area on the base side is small.

[0018]

According to the present invention, since the wall surface of the through recess formed in the insulating film is inclined so that the opening area becomes smaller toward the lower side opening, the conductivity in the above step (3) is increased. When the paste is printed and filled, the conductive paste is filled along the inclined wall surface on the front side in the printing progress direction,
At the same time, the air in the through recesses can escape from the inclined wall surface side in the printing direction, so that the conductive paste can be stably filled in the through recesses without bubbles.

Therefore, the conduction between the internal wirings is ensured by the via-hole conductor, and the multilayer ceramic circuit board in which the reliability of the conduction between the internal wirings is improved can be easily manufactured.

In addition, the function and effect of the laminating method by applying the slip material, that is, the surface of the insulating film can be always kept uniform, and the conductor film which is the internal wiring formed on the surface does not have a step breakage and the through recess The shape can be changed arbitrarily, and at the same time, it is possible to perform batch processing at the same time, and it is possible to enjoy the ease of alignment.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view of a multilayer ceramic circuit board according to the present invention, and FIGS. 2A to 2H are cross-sectional views illustrating a manufacturing method thereof. Although the description will be given using a laminated ceramic circuit board including five insulating layers, the number of laminated layers can be arbitrarily changed.

In the figure, reference numeral 1 is a laminated body, and 1a
1e is an insulating layer, 2 is an internal wiring, 3 is a via-hole conductor,
Reference numeral 4 is surface wiring, and 5 and 6 are electronic components.

The laminated body 1 includes insulating layers 1a to 1e, internal wirings 2 arranged between the insulating layers 1a to 1e, a plurality of internal wirings 2 arranged in different layers, or an internal wiring 2 And a via hole conductor 3 for connecting between the surface wiring 4 and the surface wiring 4.

The insulating layers 1a-1e are, for example, 850-10.
Glass that enables firing at relatively low temperatures around 50 ° C
Made of ceramic material, its thickness is 40 ~ 120μm
Is. The internal wiring 2 is arranged between the plurality of insulating layers 1a to 1e.

The internal wiring 2 is made of a gold-based, silver-based or copper-based metal material, for example, a silver-based conductor. Further, the internal wiring 2 between the different insulating layers 1a to 1e is connected by the via-hole conductor 3 penetrating the thickness of the insulating layers 1a to 1e.

The via-hole conductor 3 is also made of a gold-based, silver-based, or copper-based metal material, for example, a silver-based conductor, like the internal wiring 2.

A surface wiring 4 made of a silver-based or copper-based metal material, such as a copper-based conductor, is formed on the surface of the laminated body 1 so as to be connected to the via-hole conductor 3 formed in the insulating layer 1a. If necessary, a thick film resistor film 5 or a thick film protective film (not shown) may be formed on the surface wiring 4,
Various electronic components 6 including a plating process and an IC are joined by solder or bonding fine wires.

The above-mentioned laminated ceramic circuit board is shown in FIG.
It is formed by the steps shown in (a) to (h).

First, as shown in FIG. 2A, an insulating film 10e to be the insulating layer 1e is formed on a work substrate 15 (corresponding to a base) made of heat resistant resin, glass, ceramics or the like.

The insulating film 10e is formed by uniformly kneading ceramic powder, a glass material, an organic binder, and an organic or aqueous solvent, and applying and drying the slip material to a thickness of about 40 to 120 μm.

Since the front surface wiring is not formed on the main surface on the back surface side of the laminated body 1 shown in FIG. 1, it is not necessary to form a via-hole conductor in the insulating layer 1e.
Is formed by simply applying the above-mentioned slip material and drying it. However, when forming a via-hole conductor in the insulating film 10e, a photo-curable monomer is further added to the slip material, and 2 (c) to FIG. 2 (e), it is necessary to perform selective exposure / development processing.

Examples of the above-mentioned ceramic powder include materials such as cristobalite, quartz, corundum (α-alumina), mullite, zirconia and cordierite.
The average particle size of the powder is preferably 1.0 to 6.0 μ.
m, and more preferably 1.5 to 4.0 μm. Two or more kinds of these ceramic materials may be mixed and used.

In particular, the use of corundum is advantageous in terms of cost.

Here, the average particle size of the ceramic powder is 1.
The average particle size is 1.0 μm, which is set to 0 to 6.0 μm.
If the amount is less than the above, it is difficult to homogeneously mix and slip, and the exposure light is diffusely reflected at the time of the exposure processing described later, and sufficient exposure cannot be performed. On the contrary, if the average particle size exceeds 6.0 μm, the dense laminated body 1 having high strength cannot be obtained.

The above-mentioned glass material is a glass frit containing a plurality of metal oxides and has a temperature of 850 to 1050 ° C.
After calcination in 1., at least one crystal of cordierite, mullite, anorthite, sergian, spinel, garnite, willemite, dolomite, petalite or a substituted derivative thereof is precipitated.

In particular, when a crystallized glass frit which deposits anorthite or sersian is used, a laminated body having higher strength can be obtained, and when a crystallized glass frit which deposits cordierite or mullite is used, Since the coefficient of thermal expansion after firing is low, it is effective as a circuit board for disposing a silicon chip such as an IC on the circuit board.

The most preferable glass materials in consideration of the strength and the coefficient of thermal expansion of the insulating layer are B ₂ O ₃ and Si.
A glass frit containing O ₂ , Al ₂ O ₃ , ZnO, and an alkaline earth oxide. Since such a glass frit has a wide vitrification range and a yield point around 600 to 800 ° C., it is suitable for low temperature firing at about 850 to 1050 ° C., and copper-based and silver to be the internal wiring 2 and the via-hole conductor 3. It is suitable for the sintering behavior of metallic and gold-based conductive materials.

The glass material is mixed in the slip material in a frit state. The average particle size of this frit is
It is 1.0 to 5.0 μm, preferably 1.5 to 3.5 μm. Here, if the average particle diameter is less than 1.0 μm, it is difficult to make slippage, and the exposure light is diffusely reflected at the time of exposure described later, and sufficient exposure cannot be performed. On the other hand, if the average particle diameter exceeds 5.0 μm, the dispersibility is impaired, and specifically, it cannot be uniformly dissolved and dispersed between the ceramic powders that are the insulating material, and the strength is greatly reduced.

The composition ratio of the above-mentioned ceramic material and glass material is such that when firing at a relatively low temperature of 850 to 1050 ° C., the ceramic material is 10 to 50 wt%, preferably 20 to 35 wt%. Is 90-50
wt%, preferably 80-65 wt%.

Here, if the ceramic material is less than 10 wt% and the glass material exceeds 90 wt%, the insulating layer is excessively vitreous, which is inappropriate from the viewpoint of the strength of the insulating layer. Material exceeds 50wt%,
When the glass material is less than 50 wt%, the exposure light is diffusely reflected at the time of exposure described later, sufficient exposure can be performed, and the denseness of the insulating layer after firing is also impaired.

In addition to the above-described solid components such as ceramics and glass, the constituent material of the slip material is a photocurable monomer that is lost by sintering, an organic binder,
Contains an organic solvent.

The photo-curable monomer is excellent in thermal decomposability in order to cope with a low temperature and short-time baking process. As the photo-curable monomer, a slip material can be exposed by exposure after coating and drying. It is necessary to photopolymerize, free radical formation, chain growth addition polymerization are possible, and a monomer having a secondary or tertiary carbon is preferable, for example, butyl acrylate having at least one polymerizable ethylene group. Alkyl acrylates and their corresponding alkyl methacrylates are effective.

In addition, polyethylene glycol diacrylates such as tetraethylene glycol diacrylate and their corresponding methacrylates may be mentioned.

The photo-curable monomer is added in a predetermined amount so that the insulating film 10e is cured by the selective exposure treatment and the portion other than the exposed portion can be easily removed by the development treatment. For example, it is 5 to 15 wt% or less with respect to the solid component (ceramic material and glass material).

The organic binder should have good thermal decomposability as well as the photocurable monomer. At the same time, since it determines the viscosity of the slip, the wettability with the solid content must be emphasized.According to the study of the present inventor, a carboxyl group such as acrylic acid or methacrylic acid-based polymer and an alcoholic hydroxyl group are determined. The ethylenically unsaturated compounds provided are preferred. Addition amount is 25 based on solid content
Wt% or less is preferable.

As the solvent, an aqueous solvent can be used in addition to the organic solvent. In this case, the photocurable monomer and the organic binder must be water-soluble, and the monomer and the binder should be used. , Hydrophilic functional groups such as carboxyl groups are added. The amount of addition is 2 to 300, preferably 5 to 100, when expressed by acid value. If the addition amount is small, the solubility in water and the dispersibility of the powder of the fixed component will be poor, and if it is large, the thermal decomposability will be poor. In consideration of the above, it is appropriately added within the above range.

In any type of slip material, the photocurable monomer and the organic binder must have good thermal decomposability as described above, but specifically, 60
It must be capable of thermal decomposition below 0 ° C. More preferably, it is 500 ° C. or lower.

When the thermal decomposition temperature exceeds 600 ° C., it remains in the insulating layer and is trapped as carbon, which causes the substrate to turn gray and the insulating resistance of the insulating layer to decrease. Also, it may become void and cause delamination.

Further, a sensitizer, a photoinitiator material, etc. may be added to the slip material as required. For example, examples of the photoinitiator-based material include benzophenones and acyloin ester compounds.

Examples of the method of applying the above-mentioned slip material include a doctor blade method (knife coating method), a roll coating method, a printing method and the like. In particular, a doctor blade method or the like is preferable because it makes it easy to flatten the surface of the insulating film after coating. The amount of the solvent added is adjusted according to the coating method to adjust the viscosity to a predetermined value.

As a drying method, a batch-type drying furnace or an in-line-type drying furnace is used, and the drying condition is 120 ° C.
The following is desirable. Also, rapid drying may cause cracks on the surface, so it is important to avoid rapid heating.

Next, as shown in FIG. 2B, the insulating layer 1
The conductor film 20 serving as the inner conductor 2 disposed between the e and the insulating layer 1d is printed in a predetermined shape by screen printing using, for example, an Ag-based conductive paste, and dried. The conductor film is preferably about 20 to 50 μm.

The conductive paste is a powder of at least one metal material of gold, silver, copper or alloys thereof, for example, silver powder, a low melting point glass component, an organic binder, an organic solvent, and, if necessary, the above-mentioned materials. A homogeneously kneaded photo-curable monomer is used.

In particular, since the firing temperature is relatively low at 850 to 1050 ° C., a low melting point glass component having a yield point of 700 to 800 ° C. is used in consideration of the sintering behavior of the insulating films 1 a to 1 e. This is very important.

If necessary, the entire conductor film 20 may be exposed to light to be photocured. this is,
In the process shown in FIG. 2E, which will be described later, when a developing process is performed to form the penetrating recess 30 in the insulating film 10d applied / formed on the conductor film 20, the conductor film 20 is attacked by the developing solution. That is, it is not necessary to apply a conductive paste photocurable monomer or an exposure treatment as long as it is not attacked by the developing solution.

Next, as shown in FIG. 2C, the insulating film 10d to be the insulating layer 1d is applied and dried using the above-mentioned slip material so as to completely cover the above-mentioned conductor film 20. .

Here, the base body is not the work substrate 15 alone, but the base body including the insulating film 10e and the conductor film 20 to be the internal wiring formed before this step.

Next, as shown in FIG. 2D, the insulating layer 1
At a predetermined position of the insulating film 10d corresponding to the via-hole conductor 3 penetrating in the thickness direction of d, the solubilized portion 30 'to be the through recess 30 is formed.
Is formed by exposure processing.

Since the photo-curable monomer of the insulating film 10d is a negative type which undergoes photo-polymerization, the solubilized portion 3 to be the through recess 30 is formed.
Only 0'is performed without exposing the exposure light.
Specifically, on the surface of the insulating film 10d, a photo target having a predetermined pattern in which only the solubilized portion 30 'to be the penetrating recess 30 is not exposed is placed on or near the surface of the insulating film 10d, and low pressure Irradiate the exposure light of high-pressure and ultra-high-pressure mercury lamp system. By this selective exposure processing, the insulating film 1d
A portion other than the through-hole concave portion 30 causes a photopolymerization reaction of the photocurable monomer. The exposure device may be a general one used in so-called photolithography.

Next, as shown in FIG. 2E, the exposed insulating film 10d is subjected to a development process to remove the solubilized portion 30 'and form a through recess 30. Thereby, the through recess 3
A part of the conductor film 20 which becomes the internal wiring 2 printed and formed in FIG. 2B is exposed at the lower part of 0.

As this development processing, chlorocene, 1,
1,1-trichloroethane and an alkali developing solvent are applied to the solubilized portion 30 'by, for example, a spray developing method or a paddle developing method.
The developing process is performed by spraying or contacting the surface. Then, if necessary, washing and drying are performed.

Next, as shown in FIG. 2F, the insulating film 1
The conductor 3 to be the via-hole conductor 3 is provided in the through recess 30 of 0d.
1 is formed by filling and drying a conductive paste.
The filling method is, for example, a screen printing method.

Next, as shown in FIG. 2G, the insulating layer 1
The conductor film 20 to be the internal wiring 2 arranged between the d and the insulating layer 1c is printed and dried using a conductive paste. The printing method is, for example, a screen printing method. If necessary, the entire surface of the conductor film 20 is exposed to light to be photocured.

Next, the insulating film to be the insulating layer 1c is formed as shown in FIG.
2C, and then a through recess of the insulating film to be the insulating layer 1c is formed as shown in FIGS. 2D and 2E, and a conductor to be the via-hole conductor 3 is formed in this through recess. Is formed as shown in FIG. 2 (f), and the insulating layer 1c and the insulating layer 1b are formed.
The conductor film which becomes the internal wiring 2 disposed between and is shown in FIG.
It is formed as shown in.

By repeating this, as shown in FIG. 2H, the conductor 31 serving as the via-hole conductor 3 ... Is formed in the insulating film 10a serving as the uppermost insulating layer 1a.
The superposing step of the unfired laminated body 1 is completed. And
This unbaked laminated body 1 is divided into individual laminated bodies by press molding to form dividing grooves,
The work substrate 15 and the laminated body 1 are separated.

Next, the insulating films 10a to 10e and the internal wiring 2
The conductor film 20 that becomes
The laminated body 1 in which 0 is arranged is integrally sintered.

Sintering consists of a binder removal process and a firing process. In the binder removal process, the insulating films 10a to 10e, the conductor film 20 to be the internal wiring 2, and the conductor 3 of the via-hole conductor 3 are used.
This is because the organic component contained in 1 disappears, and for example, 6
It is not higher than 00 ° C.

In the baking process, the insulating films 10a to 10e are used.
By sufficiently softening the glass component of (1) to uniformly fill the grain boundaries of the ceramic powder to achieve a certain strength of the laminated body 1, and at the same time, the silver powder of the conductor film 20 and the conductor 31 is grain-grown. In addition to lowering the resistance, it is integrated with the insulating layer, and is performed at a peak temperature of 850 to 1050 ° C. in an oxidizing atmosphere or a neutral atmosphere.

On the surface of the sintered laminated body 1, as the surface conductor 4, printing and baking are performed using a copper-based conductive paste that can be fired at a low temperature (for example, 780 ° C. or lower), and if necessary, a thick film resistance is applied. Body film 5 is formed by baking, surface conductor 4
An electronic component such as an IC chip or a chip component is bonded to the top and divided individually along the dividing groove. As a result,
The multilayer ceramic circuit board shown in is achieved.

Since the surface conductor 4 is a copper-based material,
Baking must be done in a reducing atmosphere. For this reason, it is impossible to perform integral sintering at the same time as the laminated body, but if a silver-based conductor, for example, simple silver or a silver-palladium alloy, is used for the surface conductor 4, the surface conductor will be formed on the laminated body 1 before firing. It is possible to print a conductor of No. 4 and perform integral sintering simultaneously with the laminated body.

The feature of the present invention is that, as shown in FIG. 3A, the wall surfaces 30a and 30b of the through recess 30 formed in the insulating film 10 in which the via-hole conductor 3 is formed have the upper side opening diameter. That is, the lower conductor 20 is inclined with respect to D so that the lower opening diameter d through which the lower conductor 20 is exposed becomes small.

As a result, as shown in FIG. 3B, when the conductive paste 34 is filled with the squeegee 33 through the screen 32, the side surface 30a of the squeegee 33 on the front side in the advancing direction thereof. When the conductive paste 34 flows in from the squeegee 33 and further advances,
As shown in (c), the air in the through recess 30 easily escapes from the wall surface 30b side of the squeegee 33 in the traveling direction, and eventually, the inside of the through recess 30 is electrically conductive without generating bubbles. The conductive paste 34 can be completely filled.

Here, the through recess 30 having the above-described shape can be easily formed under the exposure condition and the developing condition.

For example, the exposure conditions are such that the exposure is carried out at a relatively low intensity, for example, about 50 mJ / cm ² , and the development conditions are as follows: the development time is short, for example, about 30 seconds, and the developing solution dilution ratio is high, This is achieved by using a solution of concentration.

Here, the inclination angle θ shown in FIG. 3 (a) is about 65 to 85 ° although it is slightly different depending on the viscosity of the conductive paste, the printing pressure of the squeegee, and the speed. Inclination angle θ
Is less than 65 °, the displacement between the upper side opening diameter D and the lower side opening diameter d becomes large, the area required to form the via-hole conductor 3 increases, and it becomes difficult to make small-sized and high-density wiring.

Further, when the inclination angle θ exceeds 85 °, bubbles are often generated at the bottom of the through-hole recess 30 even when the through-hole recess 30 is filled with the conductive paste 34, and the need for conduction of the via-hole conductor 3 becomes remarkable. .

Here, in the case of forming a conductor to be a via-hole conductor by the conventional green sheet multi-layer method, a green sheet having a thickness of 100 to 200 μm is die-molded or NC punched to form a via-hole conductor at both positions. A through hole with an open surface is formed, and this through hole is filled with a conductive paste. However, since both surfaces are open, it is possible to form a through hole with a large opening diameter. At the time of filling, the paste cannot be held in the through hole, and the paste will be lost. Therefore, the diameter of the conventional through hole is
The upper limit was about 100 to 200 μm.

On the other hand, the through recess 30 according to the present invention.
In this case, since the paste is not removed, it is easy to make the via-hole conductor 3 having a relatively large current capacity such as a power supply voltage or an earth potential system any shape according to the purpose. That is, the upper opening diameter D and the lower opening diameter d of the penetrating recess 30 should be relatively large in relation to the power supply voltage and the ground potential, and relatively small in order to increase the density of the signal system. Is desirable. The upper opening diameter D of the via-hole conductor 3 of the signal system is set to 60.
˜150 μm, and the lower opening diameter d can be set to about 40 to 100 μm.

Incidentally, in the above-mentioned embodiment, FIG. 2 (f) (g)
As shown in, filling the conductor to be the via-hole conductor 3,
Although the conductor film to be the internal wiring 2 is printed in different steps, as shown in FIG. 3, in the same step, the conductor 31 to be the via-hole conductor 3 is filled by one screen printing and the internal wiring 2 is formed. The conductor film 20 to be used may be printed. Further, the conductor 31 and the conductor film 20 may be photo-cured if necessary. Of course, in this case, a photocurable monomer is added to the conductive paste.

Further, in the above-mentioned embodiment, the surface wiring is only on the front surface side main surface of the laminated body 1, but the surface wiring and various electronic parts can be mounted also on the back surface main surface of the laminated body 1. it can. In this case, the insulating film 1 serving as the insulating layer 1e on the back surface side
After forming 0e, selective exposure processing and development processing are performed,
The through recess 30 is formed, and the through recess 30 is further filled with the conductor 31 to be the via-hole conductor 3.

Further, as the work substrate 15, a fired ceramic substrate having internal wiring printed thereon may be used. In this case, it is not necessary to separate the work board 15.

As the internal wiring 2, Au system, Ag, etc.
Insulating layer 1a because a low-melting metal material such as Cu-based or Cu-based is used
Although a material containing glass ceramic as a main component is used also for 1f, a high melting point metal material such as tungsten or molybdenum may be used for the internal wiring 2. in this case,
Since the sintering temperature is around 1300 ° C., the composition of the glass component in the insulating layer that is similar to the sintering behavior of the metal material such as tungsten and molybdenum can be changed, the glass component,
The composition ratio of the ceramic component, for example, the glass component may be less than 10% by weight.

[0083]

As described above, according to the present invention, since the wall surface of the through recess serving as the via-hole conductor is inclined so that the upper opening area is large and the lower opening area is small, the through recess is electrically conductive. When the conductive paste is printed / filled, the conductive paste can be completely filled without generation of bubbles, and a conductor that becomes a via-hole conductor without any dent on the surface can be formed.

Therefore, the connection between the internal wiring patterns electrically connected to each other by the via-hole conductor is ensured, and the multilayer ceramic circuit board in which the reliability of conduction between the internal wirings is improved can be easily manufactured.

Further, the surface of the insulating film can be always kept uniform, the internal wiring pattern formed on the surface is not discontinuous, the shape of the penetrating recesses can be arbitrarily changed, and at the same time, batch processing can be performed. It is possible to manufacture a multi-layer ceramic circuit board having a simple manufacturing method such as easy manufacturing process and high internal wiring reliability.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a multilayer ceramic circuit board according to the present invention.

2A to 2H are schematic cross-sectional views for explaining each manufacturing process of the multilayer ceramic circuit board of the present invention.

3 (a) to (c) are schematic cross-sectional views showing a filling state of a through recess used in the multilayer ceramic circuit board of the present invention.

[Explanation of symbols]

 1a to 1e ... Insulating layer 10a to 10e ... Insulating film 2 ... Internal wiring 20 ... Internal conductor 3 ... Via hole conductor 31. ... Conductor member that becomes via-hole conductor 30 ... Penetrating recesses 30a, 30b ... Wall surface 4 ... Surface wiring 5 ... Thick film resistor 6.・ ・ ・ ・ Electronic parts 15 ・ ・ ・ ・ ・ ・ Work board 30 '・ ・ ・ ・ Solution

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Sakahiro Sakahiro 1-1, Yamashita-cho, Kokubun-shi, Kagoshima Prefecture Kyocera stock company Kagoshima Kokubun factory (72) Inventor Kazuma Furuhashi 1-1, Yamashita-cho, Kokubun-shi, Kagoshima Kyocera stock company Kagoshima Kokubu factory (72) Inventor Hiroshi Suenaga 1-1 Yamashita-cho, Kokubu city, Kagoshima prefecture Kyocera stock company Kagoshima Kokubu factory

Claims (1)

[Claims] 1. A glass / ceramic slip material containing a photocurable monomer is applied to the surface of a substrate.
A step of forming an insulating film by drying, (2) a step of forming a through hole by selectively exposing and developing the insulating film, and (3) a surface of the insulating film and the inside of the through hole. A step of printing / filling a conductive paste to form a conductor to be a via hole conductor and a conductor film to be an internal wiring, and (4) the steps (1) to (3) above are repeated to form an insulating film and an internal wiring. A method of manufacturing a multilayer ceramic circuit board, comprising integrally firing a conductor film and a conductor to be a via-hole conductor, wherein a hole wall surface of a through hole formed in the insulating film has a large opening area on the upper surface side. A method for manufacturing a multilayer ceramic circuit board, characterized in that it is inclined so as to reduce the opening area on the base side.