JPH1192256A - Conductor for inorganic substrate, paste for conductor and inorganic multilaered substrate using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a conductor for via holes and a conductor for an interlayer, capable of firmly and closely adhering even to the via holes and having a lower resistance than that of a conventional one without voids and wire breakage in an inorganic multilayered wiring substrate. SOLUTION: This inorganic multilayered wiring substrate is obtained by kneading a conductor material powder containing 60-99.95 wt.% metal as a principal component, 0.05-10 wt.% at least one or more of a nitride, a carbide and a boride as a secondary component and <=35 wt.% oxide glass with an organic vehicle component composed of at least an organic binder and a solvent, preparing a conductor paste, providing via holes in glassy or ceramic insulating layer sheets, filling the resultant paste therein, then carrying out the wiring pattern printing, thermocompression bonding the sheets, forming a laminate, subsequently baking the formed laminate and simultaneously sintering the laminate with the conductor material.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wiring conductor formed on an inorganic multilayer wiring board for mounting and mounting LSIs, ICs and chip components, and further relates to the formation of such a wiring conductor. The present invention relates to a paste for a conductor used for:

[0002]

2. Description of the Related Art As a multilayer wiring board on which a semiconductor IC or the like is mounted, an inorganic substrate mainly composed of a ceramic material such as alumina or a glass material generally has high heat resistance, high thermal conductivity, and high thermal expansion. It is widely used because it has excellent characteristics such as low reliability and high reliability.

An important point in the production of an inorganic multilayer substrate is that the substrate is produced by firing a green sheet formed of ceramics, glass, or a mixture thereof at a high temperature. Is to shrink. Due to this shrinkage, a dimensional error occurs in the substrate, and the product yield decreases. In order to overcome this problem, there has been proposed an inorganic multilayer substrate which shrinks only in the thickness direction and hardly shrinks in the plane direction (JP-A-5-10266).
No. 6, etc.).

[0004] Another problem due to the sintering shrinkage of the substrate is the difference in the sintering temperature and the shrinkage ratio between the substrate and the wiring conductor formed therein. The wiring conductor formed on the multilayer substrate is a film-like conductor that is patterned and wired on the outermost surface layer or between two adjacent insulating layers (hereinafter simply referred to as an interlayer conductor, including the surface layer conductor). And via conductors which are filled in via holes penetrating the insulating layer and connect to upper and lower interlayer conductors.

[0005] An example of a general method for producing an inorganic multilayer substrate including these wiring conductors is as follows. First, prior to firing, a green sheet of an insulating inorganic material having a predetermined shape is formed on a green sheet of an insulating inorganic material. A through hole is formed at a position, and the hole is filled with a conductive material containing metal powder for conductivity or a paste containing the conductive material. Next, on this green sheet,
A pattern is formed with a conductor material or its paste by applying a thick film printing technique or the like. Thereafter, several of these green sheets are laminated, integrated, and fired to produce a multilayer wiring board integrally formed with the wiring conductors.

In the above method, the wiring conductor and the insulative inorganic substrate are formed by simultaneous sintering. In the simultaneous sintering, the starting and ending temperatures of the sintering and the shrinkage after sintering are reduced. If there is a difference, separation occurs between the two, the interlayer conductor and the via conductor are cut, and a void is generated inside the via conductor, so that the connection reliability to the laminated substrate is significantly reduced. In order to prevent this, a glass component and other fillers are generally added to the conductor material in addition to the metal. Since the glass component softens at a relatively low temperature, it has a role of generating an adhesive force between the insulating inorganic substrate and the wiring conductor, but the addition of the glass lowers the sintering temperature of the insulating inorganic substrate. It will be lower than the sintering temperature, so that the conductor will sinter before the substrate,
There has been a problem that voids are generated in the conductor or the conductor is partially separated from the substrate material. Therefore, in order to prevent a decrease in the sintering temperature of the conductor, relatively hardly sinterable alumina or the like is added as a filler to control the sintering temperature and shrinkage of the conductor material.

[0007]

However, since these glass and other additives such as alumina are insulators, adding them to the conductor material inevitably increases the resistance of the conductor. There was a point.

The present invention has been made to solve the above-mentioned problems, and is a conductor used for wiring of an inorganic multilayer substrate. The conductor is used for disconnection, internal voids, peeling from the substrate, etc. in a sintering process. It is an object of the present invention to provide a wiring conductor free from defects. It is another object of the present invention to provide a wiring conductor which can prevent the above-mentioned defects of the conductor during the firing process and at the same time has the lowest possible electrical resistance.

Another object of the present invention is to prevent defects in the conductor in the process of sintering the conductor simultaneously with the inorganic multilayer substrate in the firing step, and to reduce the electric resistance of the conductor. An object of the present invention is to provide a conductive paste. Another object of the present invention is to provide an inorganic multilayer substrate using such a sintered conductor.

[0010]

The wiring conductor of the present invention comprises:
A conductor used for wiring of an inorganic multilayer substrate, which is generally a sintered body containing a conductive metal and a non-oxide high-melting substance such as a nitride, carbide, or boride. . This conductor is used for an inorganic substrate having a sintering temperature higher than the sintering temperature of the conductor, and a paste containing the conductor material is applied to an inorganic multilayer substrate, and the conductor material is simultaneously sintered when the substrate is fired. The metal in the sintered conductor develops conductivity.

The non-oxide type high melting point compound is controlled so as to increase the sintering temperature of the conductor by the amount of addition, and by adding a small amount, the sintered body is sintered without increasing the specific resistance of the conductor. This has an effect of effectively preventing the above-mentioned defects generated during the sintering process of the conductor. That is, the sintering temperature and timing are adjusted so that the non-oxide type high melting point substance is added with a relatively small amount to increase the sintering temperature of the entire conductor and sinter almost simultaneously with the sintering of the inorganic multilayer substrate material. Control, the difference between the shrinkage of the substrate and the shrinkage of the sintered conductor, which is likely to occur in the sintering process, is reduced as much as possible, and the occurrence of separation or gap between the two due to the difference in shrinkage is prevented, This prevents defects such as disconnection of the conductor, which are likely to occur when the conductor contracts more.

In the present invention, the term "non-oxide type high melting point compound" refers to a firing method for shifting the sintering temperature of a sintered material containing conductive metal particles to a high temperature side without melting even at the firing temperature of the inorganic substrate. It refers to a substance having binding characteristics and does not include oxides. Typically, nitrides, carbides, and borides are used as such non-oxide high melting point compounds. However, it is not excluded that the conductor contains a high-temperature oxide such as oxide glass or alumina together with a non-oxide high-melting substance.

The conductor of the present invention is, specifically, 60 to 99.95% by weight of a conductive metal and 0.05 to 10% by weight of a non-oxide type high melting point substance such as nitride, carbide, boride and the like. And a composition containing 30% by weight or less of oxide glass.

[0014] The oxide glass in the sintered conductor is an optional component, but when present, improves the adhesion or adhesion between the wiring conductor and the inorganic multilayer substrate, and removes or removes the conductor. This has the effect of effectively preventing voids inside the via conductor.

Depending on the sintering temperature and sinterability of the selected inorganic multilayer substrate, and the sinterability of the selected conductor metal, From within the range, it can be determined to be a sound conductor with no defects and a low resistivity.

The wiring conductor of the present invention is used as an interlayer conductor patterned on each insulating layer of an inorganic multilayer substrate. Preferably, the wiring conductor penetrates each insulating layer from front to back to connect between the interlayer conductors. It can be used as a via conductor.

The present invention also provides a conductor paste for forming the above-described wiring conductor, and the conductor material constituting the paste includes a conductive metal, a nitride, a carbide, a boride and the like. It comprises at least one or more non-oxide high melting point compounds and oxide glass as an optional component. This conductor material is previously blended with the above-mentioned conductor composition, blended and kneaded in a resin binder to form a conductor paste. The conductor paste is applied or filled on each of the insulating layers as described later, and the respective insulating layers are stacked to form a green sheet laminate, which is then fired to integrally form the conductor in the substrate.

In the conductor paste of the present invention, a precursor of the conductor material may be used together with or in place of the metal. Here, the precursor refers to a compound that can be converted to a simple metal by some kind of chemical change in the process of firing the substrate. Specifically, the precursor includes a substance that can be easily reduced to a metal by a reducing gas, for example, hydrogen or carbon monoxide in the process of firing the substrate, and includes an oxide, a hydroxide, and a carbonate of the metal. Includes salts and other metal salts. In addition, the precursor includes a substance that can be converted to a metal with thermal decomposition in a firing process of the substrate, and includes, for example, an organic metal.

A conductor material containing a metal precursor or a paste thereof is converted into a metal at the same time as or before the sintering step in the step of firing the inorganic multilayer substrate, and the metal is converted into a metal during the sintering step. It is a sintered conductor.

Further, the multilayer substrate of the present invention is characterized by having at least an insulating layer made of an inorganic insulating material and a conductor made of the above-mentioned conductor paste. In particular, as the inorganic multilayer substrate, on both surfaces or one surface of a green laminate having at least an insulating layer made of an inorganic insulating material and the conductor paste composition, it is difficult to perform sintering including an inorganic composition that does not sinter by a baking treatment. It is preferable that the green sheet is obtained by laminating a green sheet having a property, performing a baking treatment, and then removing the non-sinterable sheet that does not sinter.

[0021]

DETAILED DESCRIPTION OF THE INVENTION First, with respect to a multilayer inorganic substrate in which the conductor of the present invention is used, the inorganic insulating material constituting the substrate is not particularly limited, and the heat radiation and strength of the substrate and the manufacturing cost are taken into consideration. Is appropriately determined. Inorganic insulating materials include
There is a glass type or a ceramic type, and a mixed type of glass and ceramics can also be used.

Glass-based substrates can be used at a lower sintering temperature, which is advantageous for reducing substrate manufacturing costs. As the glass used for the inorganic insulating material, in the case of crystallized glass, for example, borosilicate glass, borosilicate glass such as lead borosilicate or calcium borosilicate, or the like is used. In the system, for example, silicate glass or aluminosilicate glass can be used.

On the other hand, the ceramic substrate has the advantages that the sintering temperature is high, but the energy loss of the substrate is small and the thermal conductivity is good. As such a ceramic, for example, alumina can be used.

The conductive metal as the main component in the sintered conductor and the conductor material is not particularly limited as long as it can be sintered at the sintering temperature of the inorganic multilayer substrate and has good conductivity. But not preferably, copper, silver, gold, palladium,
Platinum or nickel or their alloys are used. Any of these metals may be appropriately selected depending on the method of manufacturing the substrate and the state of use. Copper and silver are particularly preferably used because the metal itself has a particularly low specific resistance.

The content of the metal in the conductor may be appropriately determined according to the required conductivity and denseness, but is preferably 60% by weight or more in the conductor. If the amount of the metal is too small, the conductivity becomes poor.

The conductor of the present invention is added with a small amount of a non-oxide high-melting substance such as a nitride, a carbide or a boride, together with such a metal. This high-melting substance is used that does not melt and soften at the sintering temperature of the inorganic multilayer substrate but raises the sintering temperature of the sintered conductor. As the high melting point material, nitrides, carbides, and borides of groups IVa, IIIb, and IVb of the periodic table are used, and examples thereof include TiC, TiN, ZrC,
BN, B ₄ C, AlN, SiC, Si ₃ N _{4 and the} like. In addition, nitrides, carbides, and borides of transition metals from Group Va to Group VIII can be used, and examples thereof include TaB ₂ and WC. Among the above compounds, the non-oxide high melting point material is particularly preferably TiN, BN, or SiC. As the conductive metal, a combination of high melting point materials TiN, BN and SiC with respect to copper or silver is preferably employed.

The compounding amount of the high melting point compound is suitably in the range of 0.05 to 10% by weight in the sintered conductor.
If it is less than 5% by weight, the amount of addition is too small, and the sintering temperature of the conductor is determined by the sintering of the conductor metal and the oxide glass added thereto, and the sintering temperature is lower than the sintering temperature of the substrate. In the case of a low conductor, the sintering of the metal or oxide glass of the conductor proceeds prior to the sintering of the substrate, so that the conductor is liable to be disconnected due to shrinkage, and the defect of the conductor cannot be prevented.
When the content of the high melting point compound exceeds 10% by weight, the sintering temperature of the conductor becomes too high, and the sintering temperature is insufficient at the substrate sintering temperature. Is peeled off from the substrate, or in the case of a via conductor, protrudes from the substrate, and the conductor is likely to be porous, leaving voids (pores) in the conductor.

The content of the non-oxide type high melting point substance in the conductor is within the above range, and the conductor is sintered and the substrate material is sintered in consideration of the type of the conductive metal and the type of the insulating phase material of the substrate. It is selected so as to substantially coincide with the knotting, and to cause adhesion of the conductor to the substrate.

In addition to the above-mentioned non-oxide type high melting point compound, it is also possible to contain oxides such as conventionally used oxide glass and alumina. As the oxide glass component, one that softens at a temperature lower than the sintering temperature of the insulating layer material of the inorganic multilayer substrate is used, and crystallized glass,
Any of amorphous glasses can be used. For example, borosilicate glass, borosilicate glass such as lead borosilicate glass and calcium borosilicate, and silicate glass and aluminosilicate glass can be used.

The oxide glass component is 0 to 30% by weight, and the glass component may not be added in the case of the inner layer of the multilayer substrate or the surface conductor. In the via conductor, if the glass component is not included to some extent, the adhesiveness to the via wall on the substrate side deteriorates. On the other hand, if the glass component is too large, the conductor resistance increases.

In order to form the above-mentioned sintered conductor, the composition of the conductor material is adjusted so as to obtain the above-mentioned sintered conductor composition after sintering, and this conductor material is kneaded with a resin binder.
Prepared into a paste. This paste is applied or filled in a required form on a green sheet for forming the above-mentioned substrate, and finally fires the multilayer green sheet, whereby a sintered conductor is formed in the multilayer substrate.

The conductor material has basically the same composition as the sintered conductor after sintering, but when the metal is easily oxidized, a precursor of the metal is particularly preferably used.
Examples of precursors include copper oxide for metallic copper, nickel oxide for metallic nickel, and the like. For example, metallic copper as a conductive metal is a conductor material that is inexpensive and has excellent migration resistance, but is easily oxidized during firing. For this reason, copper oxide is mainly used as a precursor to the metal in the conductor paste, and a reduction step is provided at the time of firing, and a metallization treatment (metallization treatment) is performed to obtain metal copper having a good conductivity. A complicated atmosphere adjustment and temperature adjustment for preventing such oxidation are not required, and the substrate can be manufactured relatively easily.

However, if all copper oxide is used, voids are likely to be generated in the conductor due to volume reduction during reduction. Therefore, it is desirable to use a mixture with metallic copper. Therefore,
For copper of the conductive metal, the precursor uses copper oxide that is easily hydrogen-reduced. In this case, the mixing ratio of the metal copper and the copper oxide is converted into the metal copper by the weight ratio, 5: 95-3
It is desirable to be within the range of 0:70.

As the organic binder, the organic vehicle component is not particularly limited, but, for example, ethyl cellulose resin, polyvinyl butyral resin, polyacrylic resin and the like can be used. As the solvent, alcohols such as terpineol and ketones can be used. it can. Further, a plasticizer or a surfactant may be appropriately added. The method of kneading the paste is not particularly limited, and for example, a three-roll mill or a ball mill can be used.

Next, a method for forming the sintered conductor of the present invention will be described. The metal and / or its precursor powder, at least one powder of nitride, carbide, boride and, if necessary, oxide glass powder are sufficiently mixed in an organic vehicle component comprising at least an organic binder and a solvent. To prepare a conductor paste for the inner layer.
A paste for via conductor is prepared in the same manner, with the same composition or a slightly changed composition ratio.

On the other hand, an inorganic insulating material for an insulating layer is sufficiently mixed and kneaded with an organic binder to prepare a slurry, and the slurry is drawn on a base film to form a sheet, which is then dried. , And a green sheet.

The green sheet is subjected to via hole processing.
Then, the via paste of the green sheet is filled with the via conductor paste. Next, after a wiring pattern is printed on the green sheets using the inner layer conductor paste, these green sheets are laminated to form a laminate. Next, in a heating furnace, the obtained laminate is first subjected to a binder removal treatment to volatilize or burn an organic component. Thereafter, a metallization treatment is performed for reduction of a precursor, and metal reduction is performed. The sintering temperature is raised to a sintering temperature, and a sintering process for maintaining the sintering temperature for a required time is performed.

A green sheet containing a hardly sinterable inorganic composition that does not sinter when the insulating sheet is fired may be laminated on both sides or one side of the green laminate. When laminating this hard-to-sinter sheet, after firing and cooling,
The hardly sinterable sheet is peeled off to obtain an inorganic multilayer substrate.

The dimensional variation of the inorganic multilayer substrate after sintering reduces the product yield. Therefore, an inorganic multilayer substrate produced by laminating a green sheet containing an inorganic composition that does not sinter in the baking treatment on both sides or one side of the green sheet laminate, shrinks only in the thickness direction at the time of baking, and in the plane direction. Since it does not shrink, it is generally difficult to increase the adhesion between the via conductor and the inside of the via hole as compared with an inorganic multilayer substrate that also shrinks in the plane direction, but in such a case, the conductor of the present invention is used for a via. Thus, a via conductor having low resistance and excellent adhesion to the via hole can be formed. The paste for the inner layer conductor and the paste for the via conductor may have the same composition.However, in general, the via conductor is liable to be peeled off from the substrate and voids. It is better to do.

A method for producing a green sheet of an inorganic insulating material is not particularly limited, for example, a doctor blade method, a calendar method, a roll coater method and the like can be used. As the base film for holding the sheet, for example, polyethylene resin, polyester resin, paper, or the like can be used.
Furthermore, as a method of performing via hole processing on the insulating sheet,
For example, punching or laser processing can be used.

The atmosphere of the calcination treatment is appropriately selected according to the treatment purpose such as the debinding step, the metallization step, and the calcination step. For example, in the debinding step, air is used to burn nitrogen and especially organic substances. When a metallizing step is included, a reducing atmosphere containing hydrogen is used. In the firing step, a reducing atmosphere may be used as it is, or nitrogen, carbon dioxide, air, and a mixed gas thereof may be used.

[0042]

EXAMPLES Specific examples of the present invention will be described below in the case where copper or silver having the lowest specific resistance is used as a metal component in a conductor material. Since copper or silver in the conductor material has a low melting point, it is necessary that the inorganic insulating material can be sintered at a low temperature. For this reason, glass-alumina mixed glass ceramics was selected as the inorganic insulating material, but the present invention is not limited to this.

Example 1 For the conductor, silver was selected as a conductive metal in the conductor, and a sintering temperature of about 90 was used as an insulating layer material.
An insulating material of a glass-alumina mixture at 0 ° C. was selected, and the effects of various nitrides, carbides, and borides were examined. Powders of silver, glass, various nitrides, carbides, and borides were mixed as raw materials for the conductor paste in a weight ratio shown in Table 1, and ethyl cellulose resin as an organic binder and terpineol as a solvent were added in appropriate amounts. This roll was sufficiently mixed and kneaded to prepare a conductor paste. For comparison, a material using alumina instead of nitride, carbide and boride was also prepared.

In order to form an inorganic multilayer substrate, 70% (weight%, hereinafter the same) of the above-mentioned glass-alumina mixed insulating material was used as a raw material of the insulating layer slurry, butyral-based resin + benzylbenzyl phthalate 15% as a binder, and , 15% by weight of butyl carbitol as a solvent,
After sufficiently mixing and kneading with a ball mill, the mixture was defoamed to prepare an insulator slurry. Using this insulator slurry, a doctor blade method is used to apply a thickness of about 200 μm on a base film (polyphenyl sulfide) whose surface has been subjected to a release treatment.
m of the insulating layer sheet was formed. For the non-sinterable green sheet, an alumina slurry was prepared in the same manner as described above using alumina powder instead of the glass ceramic powder, and an alumina sheet was formed on a base film (PET).

Next, a predetermined position of φ0.2
mm of via holes by punching, filling the via holes of the required number of insulating layer sheets with conductive paste, peeling off the base film, laminating the insulating layer sheets, sandwiching both sides with alumina sheets, at 80 ° C. The laminate was obtained by thermocompression bonding.

The obtained laminate was placed in an atmosphere in a heating furnace at 600
After the binder was removed at ℃, the sintering was further performed at 900 ℃. Thereafter, alumina on both sides of the sintered body was removed to obtain an inorganic multilayer substrate. The state of the via conductor of the obtained inorganic multilayer wiring board was observed, and the conductor resistance was evaluated for a good one. The results are shown in Table 1.

[0047]

[Table 1]

As is clear from Table 1, when observing the state of the via conductor, all of the conductors except the sample without the third component, the sample using alumina, and the sample of 25% glass + 15% alumina were observed. In this case, voids occurred in the via conductors, and the via conductors became porous. Glass 25% + Alumina 15%
The sample No. was in a good state, but had a high specific resistance value. On the other hand, those using an appropriate amount of carbides, borides and nitrides had good via states and low values of resistance. When the amount exceeded 10% by weight, the via conductor was peeled off from the substrate and protruded from the substrate.

As carbides, borides and nitrides, other than those shown in Table 1, AlN, Si ₃ N _{4 and the} like can be used.
In particular, when using TiN, SiC, and BN, the number of via defects was small and the resistance was low.

Example 2 Copper was used for the conductive metal of the conductor, and an insulating material (sintering temperature: 900 ° C.) of glass-alumina mixture was used for the substrate. The effect of composition was investigated. As a raw material for conductor paste,
Copper, glass, and BN powders were weighed so as to have the weight ratio shown in Table 2, and in the same manner as in Example 1, an appropriate amount of an organic binder and a solvent were added, and the mixture was thoroughly mixed and kneaded with three rolls. A conductor paste was prepared. For comparison, a conductor paste containing no BN was also prepared.

As a raw material of the slurry for the insulating layer, an insulating material of a glass-alumina mixture (sintering temperature: 900 ° C.), an acrylic resin as a binder, and toluene as a solvent were prepared in the same manner as in Example 1. An insulating layer sheet having a thickness of about 200 μm was prepared by a doctor blade method.

Also, for a non-sinterable green sheet,
An alumina slurry was prepared in the same manner as above using alumina powder instead of glass ceramic powder, and an alumina sheet was formed on a base film (PET).

Next, an inner diameter of 0.1 is set at a predetermined position of the insulating layer sheet.
A via hole of 5 mm is punched by punching, the via paste of the required number of insulating layer sheets is filled with the conductive paste, and an interlayer conductor is formed by screen printing using the conductive paste so that the wiring pattern has a thickness of 30 μm. After that, peel off the base film and laminate the insulating layer sheet,
The laminate was obtained by sandwiching both sides thereof with the above-mentioned alumina sheet and thermocompression bonding at 80 ° C.

The obtained laminate was placed in a heating furnace at 60 p.p. of oxygen.
The binder was removed at 700 ° C. in an atmosphere of nitrogen containing pm, and then fired at 900 ° C. in a nitrogen gas atmosphere containing 20 ppm of oxygen. Thereafter, alumina on both sides of the sintered body was removed to obtain an inorganic multilayer substrate. The resistance value of the interlayer conductor and the resistance value of the via conductor (per via) of the wiring sheet of the inorganic multilayer wiring board thus obtained, the appearance of the conductor, and the adhesion to the board were evaluated. The results are shown in Table 2.

[0055]

[Table 2]

As is clear from Table 2, BN is 0.05
%, Less than 35% glass,
In both the interlayer conductor and the via conductor, the conductor and the substrate were peeled off, and the conductor was void or cracked. on the other hand,
When the glass content exceeded 35% or the metal component was less than 60%, the resistance value increased.

If the BN content exceeds 10%, the conductor does not shrink at all during firing, and the interlayer conductor peels off from the substrate.
The via conductor protruded from the substrate, and all became defective. B
When N was in the range of 0.05% to 10%, almost good conductors were obtained irrespective of the amount of glass, and when the amount of glass was 35% or less, the resistance was relatively low. Sample No. 5 or 2
In comparison with Sample No. 4, Despite including the same amount of glass, 10, 15, and 20, the lower resistance is considered to be due to fewer defects such as voids in the conductor. In addition, in the case of via wiring, in the case where 0% of glass is not added, even if BN is contained in an appropriate amount, slight voids are generated and the conductor and the substrate are easily separated. For this reason,
For via conductors, it is more desirable that the glass component contains 5% or more.

Example 3 The composition shown in Table 3 was obtained in the same manner as in Example 1 by using powder of copper oxide, metallic copper, glass, alumina, TiN and BN as raw materials for the conductor paste for vias. A conductor paste for via was prepared at a specific ratio, and the effect of copper oxide on the conductor and the effect of the conductor composition were examined.

The insulating layer slurry was prepared in the same manner as in Example 1, and an insulating layer sheet was produced in the same manner as in Example 2. Thereafter, a via hole was punched in a predetermined portion of the insulating layer sheet by punching. Next, the via holes of the required number of insulating layer sheets are filled with a conductor paste for vias, and a wiring pattern is formed by screen printing using a paste for interlayer conductors (DD1411 manufactured by Kyoto Elex Co., Ltd.), and then the base film is peeled off. To laminate the insulating layer sheet,
Both sides were sandwiched between hardly sinterable alumina green sheets, and thermocompression bonded at 80 ° C. to obtain a laminate.

After debinding the laminate at 600 ° C. in the air in a heating furnace, a reduction treatment of copper oxide as a conductor component in the laminate was performed at 400 ° C. at 90% nitrogen-10%.
The test was performed in a hydrogen gas atmosphere. Further, firing was performed at 900 ° C. in a nitrogen atmosphere. Thereafter, alumina on both sides of the sintered body was removed to obtain an inorganic multilayer substrate. The conductor resistance and the state of the via of the obtained inorganic multilayer wiring board were evaluated. In addition, the airtightness of the via was evaluated using a flaw detection penetrant. The results are shown in Table 3.

[0061]

[Table 3]

When the starting main composition of the conductor is CuO, the binder can be removed in the air, so that there is a merit in production that delicate atmosphere adjustment as in the case of starting with metallic copper is unnecessary. The disadvantage is that the volume is reduced by the reduction of CuO → Cu.

In Table 3, sample No. It is considered that the voids in the conductor shown in FIG. 2 were caused by this volume reduction. As in the case of sample No. 1, when the amount of the copper component causing the volume decrease is reduced, voids are not generated, but the conductor resistance is increased. Then, the sample No. 3 and 4, CuO
Is partially replaced by Cu, the effect of reducing the volume is reduced, the resistance is low, and voids are not generated, but the hermeticity of the via is lost due to the reduced glass.

Therefore, while ensuring the fineness of the via conductor,
For the purpose of forming a low-resistance via conductor, the sample No. Although the glass was not reduced as in the case of 6 to 10, only the alumina was reduced, but if the amount of the filler was small, sinterability could not be controlled, resulting in defects such as poor adhesion with voids and via holes, This could not be improved by replacing copper oxide with metallic copper.

On the other hand, when the BN of the present invention was used, the sample N
o. As shown in FIGS. 11 to 17, voids were also generated when the CuO content was 100%, but by replacing the Cu content by 5% or more and 30% or less, a dense and low-resistance via conductor was obtained. This is presumably because the use of BN has an effect as a filler in a very small amount, so that both the Cu amount and the glass amount can be relatively large. The sample No. 1
6, 17 and No. 5, 9, 10, 23, 24 Cu
Is more than 40%, peeling occurs between the substrate and the via conductor,
At 100%, the via conductor was destroyed at the time of removal of the medium. This is considered to be due to volume expansion caused by oxidation of metallic copper. Sample No. Samples Nos. 18 to 24 used BN, alumina, and TiN together.
o. Almost the same results as those of 11 to 17 were obtained. Therefore,
These plural fillers can be used in combination.

[0066]

As described above, according to the present invention, the conductive material is
By containing a metal component, an oxide glass component, and at least one of nitrides, carbides, and borides, it is possible to control the sintering temperature while maintaining a large amount of the metal component in the conductor material, It can be used as an interlayer conductor and a via conductor with good adhesion to a substrate material and low specific resistance.

These non-oxide type high melting point materials are controlled by controlling their sintering temperature and shrinkage without using a large amount of oxide glass or alumina as a conventional high melting point filler.
It is possible to match the sintering temperature and the shrinkage ratio of the substrate, and as a result, a conductor having a low resistance value, no disconnection or voids in the conductor portion, and a dense structure can be formed.

Continued on the front page (72) Inventor Junichi Kato 1006 Kazuma Kadoma, Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd.

Claims (12)

[Claims] 1. A conductor integrally formed on an inorganic substrate, wherein the conductor comprises a conductive metal, one or more non-oxide high melting point materials such as nitrides, carbides and borides. A conductor for an inorganic substrate, characterized by being a sintered body containing oxide glass as a component. 2. The conductor according to claim 1, wherein the metal is 60 to 99.95.
2. The conductor for an inorganic multilayer substrate according to claim 1, comprising: by weight, 0.05 to 10% by weight of the high-melting substance, and 35% by weight or less of the oxide glass. 3. The conductor material according to claim 1, wherein the metal is copper or silver. 4. The conductor for an inorganic substrate according to claim 1, wherein the high melting point substance is TiN, SiC or BN. 5. The conductor for an inorganic substrate according to claim 1, wherein the conductor is a via conductor penetrating an insulating layer of the inorganic multilayer substrate. 6. A conductive paste containing a conductive material powder and a resin binder for integrally forming a conductive material on an inorganic substrate by sintering, wherein the conductive material is a conductive metal, a nitride, a carbide, and a boride. A paste for a conductor, comprising at least one kind of non-oxide type high melting point material such as a non-oxide type material and an oxide glass as an optional component. 7. The conductor paste according to claim 6, wherein said high-melting substance is TiN, SiC or BN. 8. The conductor paste according to claim 6, wherein the conductor material contains a precursor of the metal together with or instead of the metal. 9. The method according to claim 1, wherein said metal is copper, a precursor thereof is copper oxide, and a mixing weight ratio of copper and copper oxide is 5:95 to 30:70 in terms of metallic copper. 9. The paste for a conductor material according to item 8. 10. An inorganic multilayer substrate, comprising: a plurality of insulating layers made of an inorganic insulating material; and the conductor according to claim 1 formed integrally with said insulating layer. 11. The via conductor according to claim 1, wherein said conductor is a via conductor disposed in a layer for connection between layers.
0. The inorganic multilayer substrate according to 0. 12. A green laminate, wherein a plurality of insulating layers made of an inorganic insulating material are laminated between or within the layers by applying the conductive paste according to claim 4 or 5, on both surfaces or one surface of the laminate. A non-sinterable green sheet that does not sinter in the firing process is attached and post-fired to form a sintered body, and the non-sinterable sheet is separated from the sintered body to form an inorganic multilayer substrate. Multi-layer board.