JPH09260544A - Ceramic circuit board and manufacture therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent generating of warp, wire breaking or so on by providing an insulating part having AIN as a main component and a conductive part which is comprised of specific elements and which contains AIN with specific range of weight%. SOLUTION: A circuit board 1 is provided at a part at least with an insulating part 2 having AIN as a main component and a conductive part 3 of which main component is one of W or Mo at least, which contains one or more elements selected from a group made of Ni, Co and Fe and which also contains AIN with 0.1-20weight%. Because the AIN which is a main component of the insulating layer 2 is added as a common material to the conductive layer 3, generating of warp is significantly prevented by achieving a absorption ratio matching between the insulating layer 2 and the conductive layer 3. At least one of element selected from alkaline earth elements and rare earth elements may be contained in the conductive layer 3. The fine conductive layer is obtained by adding these.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a circuit board using an aluminum nitride sintered body as an insulating layer, and more particularly to a circuit board having a multilayer wiring in which a conductor layer and an insulating layer are integrally sintered.

[0002]

2. Description of the Related Art With the miniaturization of electronic devices, how to efficiently dissipate heat generated from semiconductor elements mounted on a circuit board has become an important issue. Conventionally, Al ₂ O ₃ ceramics have been widely used as an insulating material for circuit boards, but Al ₂ O ₃ has a low thermal conductivity and has a problem in heat dissipation. As an alternative to this, application of AlN ceramics, which has excellent electrical characteristics such as electrical insulation as an insulator and has excellent thermal conductivity, to a circuit board has been studied (Japanese Patent Laid-Open No. 60-178688). ).

Considering the miniaturization and high density of electronic equipment, the wiring of the circuit board is required to have a high density, and multilayering is an indispensable technique. AlN ceramics multilayer boards are also under consideration (Japanese Patent Application Laid-Open No. 2003-242242). Sho 60-253295,
JP-A-60-253294). Where 1,80
The AlN green sheet / conductor paste / laminate integrated sintering technology at a high temperature of about 0 ° C. already exists. However, when this technology is applied to low-temperature sintering at less than 1,600 ° C., the resistance of the conductor layer is increased, the positional accuracy is low due to the shrinkage ratio mismatch between the insulator layer and the conductor layer, warpage is generated, and the conductor circuit is disconnected. Or a problem such as peeling occurs.

Further, Japanese Patent Application Laid-Open No. 3-146488 discloses a technique in which a conductor layer containing tungsten as a main component and further containing nickel, iron, cobalt or the like is used for an AlN ceramic insulator layer. However, with this technique, it is necessary to perform the sintering treatment at a high temperature of 1,600 ° C. or higher, and the resulting insulator layer / conductor layer combination has an order of 10 ^{−8 in} the helium leak test. As can be seen from the above, it does not have a sufficient sealing effect.

[0005]

DISCLOSURE OF THE INVENTION The present invention provides a conductor layer having a low resistance, a high positional accuracy in which the contraction rates of the insulating layer and the conductor layer are matched with each other, a strong adhesion between the conductor layer and the insulator layer, and a warp. A highly heat-conductive AlN ceramic circuit board having a high reliability in that it is unlikely to cause breakage or disconnection, and in particular having a single wiring or a multi-layer wiring by simultaneous sintering, a semiconductor device using the same, and a highly heat-conductive highly reliable circuit board. The purpose is to provide a method.

[0006]

DISCLOSURE OF THE INVENTION The inventors of the present invention have found that an insulator portion containing AlN as a main component and a component containing at least one of W and Mo as a main component and selected from the group consisting of Ni, Co and Fe. It contains the above elements and 0.1 to 0.1% AlN.
It has been found that a circuit board having a conductor portion containing 20% by weight in at least a part thereof and a semiconductor device using the same can solve the above problems.

Further, the inventors of the present invention have at least one of W and Mo as main components, and contain one or more elements selected from the group consisting of Ni, Co and Fe elements in the form of a simple substance or a compound, and At least a part of the conductor portion is formed by using a conductor paste containing one or more elements selected from the group consisting of Group IIa and Group IIIa elements in the table in the form of a compound and containing AlN powder. , And 1,
It has been found that a method for manufacturing an AlN circuit board, which is characterized by sintering at less than 600 ° C., can solve the above problems.

Here, the insulator portion containing AlN as a main component means that the content of AlN in the insulating layer is 50 wt% or more and 50 vol% or more. That is, the total content of the phases other than AlN, such as the grain boundary phase component and the coloring component, in the insulator layer is 50 wt% or less and 50 vol% or less.

Further, the expression "containing at least one of W and Mo as a main component" means that the total content of W and Mo in the conductor layer is 50 wt% or more and 50 vol% or more.
In this case, Mo and W do not need to contain both components, and either W or Mo may be 0 wt% (0 vol%). Furthermore, the total content other than W and Mo in the conductor layer of other components, specifically, AlN and Group VIII element components, is 5
It should be 0 wt% or less and 50 vol% or less.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION First, an insulator layer in a circuit board according to the present invention will be described. The insulator layer is a polycrystalline body containing AlN as a main component. The strength of this insulator layer is 25
It is preferably 0 MPa or more, and more preferably 350 MPa or more by optimizing the composition and sintering conditions. Further, by adding an alkali metal element, an insulating layer having a strength of 400 MPa or more can be obtained.

The thermal conductivity is preferably 120 W / mK or higher, which is higher than that of alumina. By using AlN raw powder with low oxygen content, 140W /
Insulator layer with thermal conductivity of mK, sometimes 150W / mK
The above insulator layers can also be obtained. Also, by optimizing the sintering conditions, an insulating layer having a thermal conductivity of 210 W / mK or more can be obtained.

Next, a method of manufacturing this insulator layer will be described. First, an AlN green sheet is produced. The green sheet is obtained by, for example, a doctor blade method using a mixture of AlN powder, a sintering aid, a binder (binder) and the like, which are sufficiently mixed with a solvent.

The AlN powder used is not particularly limited, but when the thermal conductivity of the insulating layer is taken into consideration, the amount of oxygen is 3.0.
It is preferable to use less than or equal to wt% of AlN powder. More preferably, the amount of oxygen is less than 2.0% by weight, and even more preferably less than 1.3% by weight. This is because the thermal conductivity increases as the amount of oxygen in the sintered body decreases.

It is preferable that the AlN powder used has a small particle size, and the average particle size is 1.
It is preferably less than 5 μm. More preferably, 0.
Particles smaller than 8 μm, but especially smaller than 0.7 μm
A powder containing 0% by volume or more is optimal. In addition, 0.03μ
From the viewpoint of handling, it is preferable to use a powder of m or more. In addition, the cation impurities contained are 3,000 ppm.
It is preferably less than 1, more preferably 1,500
It is less than ppm, more preferably less than 900 ppm. If a large amount of cationic impurities is contained, there is a drawback that the sintered body does not have high thermal conductivity. Anionic impurities other than oxygen are preferably less than 2,000 ppm, more preferably 1,000 ppm, still more preferably less than 500 ppm. If a large amount of anionic impurities other than oxygen are contained as in the case of cationic impurities, there is a drawback that the sintered body does not have high thermal conductivity.

The sintering aid to be added may be one or more elements selected from rare earth elements and alkaline earth elements in the form of at least one of a simple substance and a compound. S
c, Y, La, Ce, Pr, Nd, Pm, Sm, Eu,
Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, C
Any of a, Sr, and Ba can be used. These rare earth elements and alkaline earth elements contribute to the densification of the AlN ceramics and trap the oxygen element in the AlN powder in the sub-constituent phase of the grain boundary, which greatly contributes to the high thermal conductivity. Particularly preferred elements are Y, which has such a large effect,
Yb, Eu, and Ca elements.

As a form of a compound containing these elements, an oxide form is particularly preferable, and a compound which becomes an oxide under sintering conditions may be used. For example, carbonates, nitrates, oxalates, sulfates, hydroxides and the like can also be used. Further, it may be a halide, an acid halide, an acetylide compound, a carbide, a hydride, a nitride, a boride, a silicide, a sulfide, etc., instead of the oxide. The optimum amount of these rare earth elements and alkaline earth elements should be determined in consideration of the amount of oxygen contained in the raw material powder, but it is preferably 0.5 to 12% by weight in terms of oxide. It is preferably 1.0 to 8% by weight. More preferably, it is 2.0 to 6.0% by weight. In addition, if both a compound containing a rare earth element and an alkaline earth element is added or a composite compound containing both elements is added, it becomes possible to sinter at a low temperature, and the sintering start temperature is lowered by 400 ° C at the maximum. Can be made. Moreover, even if a halogen compound containing a rare earth element and an alkaline earth element is added, it becomes possible to sinter at a low temperature, and the sintering start temperature can be lowered by 400 ° C. at the maximum.

Alumina may be added to improve the sinterability at low temperature. The addition amount is preferably 0.8% by weight or less, and more preferably 0.25% by weight or less.

Further, the circuit board may be colored, depending on the application.
That is, the light shielding property is required. In this case, if the IVa, Va, VIa, VIIa, and VIII elements of the periodic table are added in the form of a single substance or a compound, it is possible to shield light from the near ultraviolet region to the infrared region. The addition amount is 0.03 to 5 in element conversion.
It may be added by weight%. It is more preferable to add 0.1 to 3% by weight, and further preferably 0.2 to 1% by weight.

As a method of adding these sintering aids and the like, they may be added in advance to the raw material powder. However, depending on the type of additive, it may be added later by a method such as impregnation.

The binder used is preferably an organic polymer which decomposes at a temperature of 1,400 ° C. or lower. Specifically, one to three types of oxygen-containing organic polymer such as polymethylmethacrylate, polyvinyl butyral, polyacrylic acid ester, polyvinyl alcohol, cellulose acetate butyrate, and cellulose are mixed, and in some cases, a mixture thereof is used. May be. The type and amount of the binder and the amount of the solvent are arbitrarily selected depending on the characteristics of the AlN raw material powder, the thickness of the sheet to be produced, and the like. Further, the binder removal is N
_It may be performed in a non-oxidizing atmosphere of ₂ , Ar, H _2, or the like. Further, if it is desired to reduce the amount of carbon after debinding, H ₂ O may be contained.

An insulating layer is formed by sintering the green sheet containing the AlN powder, the sintering aid, the binder and the like as described above, and preferable sintering conditions will be described later.

Next, the conductor layer in the circuit board according to the present invention will be described.

The conductor in this conductor layer is mainly composed of Mo,
It is at least one element of W and further contains at least one element of the Group VIII elements of the periodic table. This conductor may contain Group IVa and Va elements of the periodic table as a sub-conductor component in the form of at least one of a simple substance and a compound. Furthermore, a trace amount of a low melting point noble metal element (Au, A
g, Cu, Pt, Pd, etc.) may be contained.

Ni, Co, which are Group VIII elements of the periodic table,
When Fe element is added, the main components of the conductor layer are Mo, W
Sinterability is significantly improved. This is because the liquid phase is generated in the conductor layer during the sintering, and Mo and W are promoted by the liquid phase sintering. These Ni, Co and Fe elements may be added in the form of powder of a single metal or in the form of compound. When it is added in the form of a compound, it is most preferable to add it as an oxide, but a compound which becomes an oxide may be added during sintering. Specific examples include carbonates, nitrates, hydroxides, sulfates and the like. Further, it may be added in the form of boride, silicide, hydride, fluoride, nitride, carbide, phosphide, etc., instead of the oxide.

The amount of addition is 0.01 to 5 in terms of monoxide.
A range of weight% is preferred. When the addition amount is less than 0.01% by weight, a sufficient amount of liquid phase is not generated in the conductor layer, so that sintering of Mo and W is not sufficiently promoted. That is, the sintering stops when the relative density of the conductor is low. Therefore, since the relative density is low and the shrinkage ratio is small, shrinkage ratio mismatch with the insulating layer occurs, resulting in warpage and a circuit board with low positional accuracy. Further, the He leak characteristic is also deteriorated. Moreover, if the addition exceeds 5% by weight,
Too much liquid phase is generated during sintering, causing swelling in the conductor layer due to evaporation of the liquid phase, and a large amount of high-resistance alloy phase is generated, increasing the resistivity of the entire conductor. . The addition amount is more preferably 0.05 to 2% by weight, and further preferably 0.1 to 1% by weight. When the Group VIII element is added in the range of 0.01 to 5% by weight, the relative density of the conductor layer becomes 90% or more, and the resistivity becomes 16 μΩcm or less. If the conditions are optimized, a dense and low-resistance conductor having a relative density of 95% or more and a resistivity of 14 μΩcm or less can be obtained.
If further optimized, a conductor having a low resistance of 10 μΩcm or less can be obtained. The resulting circuit board has achieved shrinkage rate matching between the insulating layer and the conductor layer, so the positional accuracy of each part is within ± 1%, and ± 0.5% for the optimized one.
It has the following positional accuracy. Further, the occurrence of warpage is suppressed, and the diagonal line becomes 20 μm / 10 mm or less. When the optimization is performed, the warp amount of the diagonal line of 5 μm / 10 mm is reduced. Furthermore, when Ni plating is applied to a conductor to which Group VIII of the Periodic Table is added, the bonding strength between the conductor layer and the plating layer can be obtained with a large value.

When using Mo or W powder having a particle size of 1.5 μm or more, particularly 2.0 μm or more, which is used for forming the conductor, the addition of the Group VIII element of the periodic table has a great effect. Thus, the addition of Group VIII of the Periodic Table promotes the contraction of the conductor, and
Low-temperature sintering at less than 1,550 ° C. or less is possible in some cases, and shrinkage ratio matching is achieved.

The conductor layer is made of AlN which is the main component of the insulating layer.
Is added in the form of co-material. Thereby, the contraction rate of the insulating layer portion and the contraction rate of the conductor portion can be easily matched. However, since the added AlN is an insulator,
Addition of a large amount is not preferable because it leads to an increase in the resistivity of the conductor layer. Also, if the addition amount is small, the effect of adding the AlN co-material is reduced, which is not preferable. The above effect is obtained when the additive amount of the co-material is in the range of 0.1 to 20% by weight. It is preferably in the range of 0.5 to 10% by weight, more preferably in the range of 1 to 5% by weight. In the circuit board to which the AlN co-material is added, contraction rate matching between the insulator layer and the conductor layer is achieved, so that warpage is extremely suppressed. Therefore, there is no need to perform a step of rewarping to eliminate warpage after sintering. As a result, the positional accuracy is ± 1% or less, and it is easily ± 0.5 if the addition amount is optimized.
% Or less. Further, regarding the Mo and W conductors, when an AlN co-material is added, shrinkage is promoted and the conductor becomes a dense conductor, so that a conductor having a low resistance can be obtained.

The conductor layer of the present invention may further contain at least one element selected from alkaline earth elements and rare earth elements. When these are added in the form of at least one of a simple substance and a compound, a dense conductor can be obtained as can be confirmed by a helium leak test. Examples of rare earth elements and alkaline earth elements include Sc, Y,
La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, T
b, Dy, Ho, Er, Tm, Yb, Lu, Ca, S
r and Ba are mentioned. Particularly, industrially, Y, Yb,
Er and Ca are preferred. Oxides of these elements are particularly preferable, and compounds that become oxides under sintering conditions can also be used. Such additives are added in the form of halides, acid halides, acetylide compounds, carbides, hydrides, nitrides, borides, silicides, sulfides, etc., as well as oxides. The content of the compound containing the rare earth element and the alkaline earth element in the conductor layer is preferably 0.01 to 15% by weight in terms of oxide. This is because if the amount is too large, the conductivity of the conductor layer is lowered, and if the amount is too small, it may not be possible to obtain the effect of preventing the conductor layer from peeling off and the substrate from warping.

When a simple substance or a compound containing an Al element is further added to the conductor layer, a dense conductor having a large relative density is obtained as compared with the case where it is not added, and the conductor layer is prevented from peeling and the joint strength is improved. Thus, it is possible to obtain the effect of preventing the warp of the substrate. For example, Al ₂ O ₃ can be mentioned. Such additives form an aluminate liquid phase upon simultaneous sintering. In addition, an aluminate liquid phase also occurs in the insulating layer during simultaneous sintering. In this way, by forming the aluminate liquid phase in the conductor layer, the liquid phase generated in the insulator layer is prevented from being sucked up by the conductor layer, and the nonuniformity of the composition in the insulator layer due to such sucking is prevented. It is possible to prevent the warp of the substrate.

The method of manufacturing the circuit board of the present invention will be described below.

First, it is possible to maintain conductivity even after co-sintering. Specifically, at least one of compounds containing Mo and W metals as main components, a simple substance of Group VIII element of the periodic table, and oxides thereof. Is made into a powder and printed in a desired pattern on an AlN green sheet. When forming a paste, one or more elements selected from Group IVa and Va elements of the periodic table may be added as a sub-conductor component in the form of at least one of a simple substance and a compound.
At this time, a via hole is formed in the green sheet using a punching machine or the like, and a conductive paste to be a sintered body is previously filled by press-fitting or printing using a metal mask. The via holes electrically connect the upper and lower conductors that sandwich the green sheet.

AlN ceramic powder is added to this conductor paste. Further, at least one element selected from rare earth elements and alkaline earth elements may be added in the form of at least one of a simple substance and a compound, and further Al ₂ O ₃ (alumina) may be added. When alumina is added in the form of a mixture with at least one of a simple substance and a compound containing a rare earth element, it is preferable to mix them in such a ratio as to form an aluminate.

Even if AlN is added only to the via hole portion where the volume of the conductor becomes large, the warp of the substrate can be suppressed to a minimum. That is, depending on the size of the board and the arrangement of the conductor layers determined by design, a circuit board with less warpage may be obtained by adding it to at least a part of the conductor layers.

After removing the binder from the multilayer green compact coated with the conductive paste containing such components, it is subjected to a sintering step. For this sintering step, known AlN
Although the sintering method performed in (3) is adopted as it is and is not particularly limited, the setter for setting in the sintering furnace can be made of various materials.
The reaction of o does not form a compound, and a low-resistance conductor is obtained. The surface roughness after sintering becomes very small and a good circuit board can be obtained. The surface roughness is the average surface roughness R
a is 1.0 μm or less. Those having a better surface have a thickness of 0.5 μm or less, and those having a better surface have a thickness of 0.3 μm or less. Generally, sintering may be performed at a temperature of 1,450 ° C. or more and less than 1,600 ° C. under a non-oxidizing atmosphere under normal pressure, increased pressure, and reduced pressure, for example, a nitrogen atmosphere or an argon atmosphere. The time required for sintering varies depending on various conditions such as the thickness of the molded body to be sintered and the sintering temperature, but generally, it may be selected from the range of 0.5 hours to 100 hours. It is preferable that an appropriate range of these conditions is determined in advance according to various conditions prior to execution.

In order to make the obtained AlN circuit board have high thermal conductivity, high density, and high strength, it is preferable to set the average heating rate in the range of 1 to 40 ° C./min particularly in a high temperature portion of 1000 ° C. or higher. . More preferably, 5 to 30 ° C / min,
More preferably, the range is 8 to 25 ° C./min. Due to the above sintering, Al having a relative density of 98% or more
An N insulating layer is obtained. As a more dense structure, 99% or more of the insulating layer can be obtained.

The circuit board manufactured in this way has the following characteristics.

First, in the circuit board of the present invention, the parallelism between the front and back is very small, warpage and undulation are very small, and the number of external terminals is very large (for example, 1.00).
Even circuit boards (with 0 or more terminals) can be easily soldered during mounting. The front and back parallelism, which indicates the presence or absence of warpage or waviness of the board, is obtained by measuring the maximum value of the warpage between the central part and the peripheral part on the basis of 10 cm diagonal line of the sintered multilayer circuit board. It is a very small value of 0.2 mm or less. In the case of a large-area circuit board, mounting can be performed by using the board according to the present invention having front and back parallelism of 0.05 mm or less.

The surface resistance and internal resistance of this circuit board are 16 μΩcm or less, which is a good value. When optimized, it becomes a more preferable value of 14 μΩcm, and in some cases 10 μΩcm or less. Since the conductor layer is formed by containing the Group VIII element of the periodic table, the density of the conductor is increased,
A conductor having a low resistivity can be obtained. Furthermore, since AlN is added to the conductor layer, the contraction behavior of the insulator layer and the conductor layer are almost the same, the contraction rate matching is achieved, and the positional accuracy of ± 1% or less is obtained. In some cases, ± 0.
Excellent position accuracy of 5% or less can be obtained. A circuit board having such positional accuracy and flatness can be easily flip-chip mounted.

Further, the joint strength between the insulator layer and the conductor layer in this circuit board has a value of 5 kg / 2 mm × 2 mm or more. 5
When the value is less than kg / 2 mm × 2 mm, when the pin is used for the external terminal, the bonding strength is insufficient, and the pin may drop between the AlN and the conductor. In particular, in the case of BGA (ball grid array package), even higher bonding strength is required when surface mounting an organic material having a large coefficient of thermal expansion such as a printed wiring board with a narrow pitch between balls. . In that case, a conductor layer composition having a bonding strength of 6 kg / 2 mm × 2 mm or more may be selected. By further optimizing it, one having a joint strength of 7 kg / 2 mm × 2 mm or more can be obtained.

A preferred semiconductor device using the circuit board of the present invention will be described with reference to FIGS. In this semiconductor device, a semiconductor 6 such as ECL (the type of element is not particularly limited) is mounted on a substrate upper surface 12a, and a multilayer ceramic circuit board 12 having a wiring pattern electrically connected to this semiconductor element. And an external terminal electrically connected to the wiring pattern and formed on the substrate lower surface 12b of the multilayer ceramic circuit substrate 12,
A high thermal conductive sealing member 13 bonded to the substrate upper surface 12a of the multilayer ceramic circuit substrate is provided so as to cover the semiconductor element 6. However, even if the external terminal and the semiconductor element are on the same main surface, they can be used without any particular problem.
The external terminals are preferably lead pins 7 as shown in FIG. 2 or solder balls 15 (BGA ball grid array) as shown in FIG.
Further, the Si element has good positional accuracy of the circuit board,
Since the flatness is also good, the flip-chip type mounting method can be easily performed. The high thermal conductivity sealing member may be made of an AlN sintered body having a thermal conductivity of 100 W / mK or more, or a metal containing an alloy.

According to the semiconductor device having the above structure, the heat generated in the semiconductor element can be efficiently transmitted to the heat radiation fins or the like (in some cases, no fin is used), and excellent heat radiation performance can be exhibited. .

When a semiconductor element is mounted on the other main surface of the AlN circuit board that faces the bonding surface of the external terminal in constructing the semiconductor device, the number of pins is increased, and The semiconductor device can be miniaturized, which is more preferable as a high-speed semiconductor device. Also, when a temperature change occurs when the semiconductor is operating and when it is not operating,
Since the insulating layer of the circuit board is made of AlN, stress is applied to the pins of the external terminals and the solder ball portions. But,
Due to its high strength, no defects such as cracks occur. Furthermore, when a semiconductor device is configured in the form of a multi-chip module (MCM) in which a large number of semiconductors are mounted on one circuit board, external terminals must be joined to the board over a large area. The point is that it is reliable enough to use.

To explain the present invention more specifically,
Examples will be described below, but the present invention is not limited to these examples.

[0044]

Embodiments of the present invention will be described below. Example 1 AlN powder containing 0.9% by weight of oxygen as an impurity and having an average particle size of 0.6 μm, Y ₂ O ₃ having an average particle size of 0.5 μm as a sintering aid, and an average particle size of 0. 0.5 μm Ca
CO ₃ , 0.5 μm of Al ₂ O ₃ and W as a colorant
O ₃ and 94.42: 3: 1.78: 0.5: 0.3
(% By weight), and wet mixing was performed for 24 hours using AlN balls to prepare raw materials. Then, an organic binder was dispersed in this raw material together with an organic solvent to prepare a slurry. After defoaming this slurry, a uniform green sheet of about 100 to 800 μm was prepared by the doctor blade method. Next, this sheet is about 130mm
Cut to a size of 130 mm and use a punching machine to make 100 to 30 via holes for connecting electrical circuits between layers.
It was opened to a thickness of 0 μm φ.

On the other hand, tungsten having an average particle size of 2.0 μm, AlN powder having an average particle size of 0.6 μm, and an average particle size of 0.
5 μm Y ₂ O ₃ powder and CaC with average particle size 0.5 μm
And O ₃ powder, and Al ₂ O ₃ powder having an average particle diameter of 0.5 [mu] m,
NiO having an average particle size of 0.8 μm was used as 97.1: 2.36
It mixed so that it might become 8: 0.075: 0.045: 0.013: 0.4 (weight%), and it mixed and disperse | distributed with the organic solvent, and produced the conductor paste of the filler addition. This inorganic filler-added tungsten paste was filled on the green sheet in which the via holes were formed using a press-fitting machine, and a circuit in the same plane was printed using a screen printing machine. The lamination process was completed by hot pressing these multiple sheets. This is cut into a size of 100 mm × 100 mm, and then, in a N ₂ + H ₂ + H ₂ O atmosphere, the maximum temperature is 90.
After debindering at 0 ° C., the debindered compact was placed in an AlN setter, and it was placed in a nitrogen atmosphere at 1 atm for 1,59
Pressure sintering was performed at 0 ° C. for 6 hours to obtain a multilayer ceramic substrate.

A disk (diameter: 10 mm, thickness: 3.5 mm) was cut out from a portion of the obtained substrate having no conductor portion, and a thermal conductivity was measured by a laser flash method using this as a test piece. As a result, it showed a high thermal conductivity of 155 W / mK. The front-back parallelism indicating the presence or absence of warpage of the substrate was determined by measuring the maximum value of the warpage between the central part and the peripheral part with reference to the diagonal line of the sintered multilayer substrate. In addition, length 1
We decided to use the value per 0 cm. As a result, 0.0
It was confirmed that the amount of warpage was as small as 4 mm. Further, the positional accuracy of each part inside the circuit board was a good value of ± 0.4%.

Next, the cross-sectional area of the conductor layer was calculated, and the conductor resistivity of the conductor layer was obtained from the resistance value. However, the surface wiring was measured without metal plating on the conductor layer, and the influence of the addition of the inorganic filler was investigated. As a result, 9.5μ
It was found to show a low resistance of Ωcm. Further, a 2 mm conductor portion of the obtained substrate was plated with Ni and soldered with a wire, and then a tensile strength test was conducted to measure the adhesive strength between the AlN substrate and the conductor layer. As a result, it was confirmed to have a very high strength of 7.0 kg.

Examples 2-35 and Comparative Examples 1-7 As shown in Table 1, AlN powder, sintering aid powder, other additives and colorants, types and amounts, conductor components, types and amounts. An AlN multilayer ceramic substrate was prepared in the same manner as in Example 1 except that the type and amount of the inorganic filler and the Group VIII additive and the sintering conditions were variously changed. The thermal conductivity, tensile strength, front-back parallelism, and conductor resistivity were measured for each. The results are shown in Table 2. As is clear from Table 2, the circuit board according to the present invention has improved adhesion strength of the conductor layer.

[0049]

[Table 1]

[0050]

[Table 2]

[0051]

[Table 3]

[0052]

[Table 4]

[0053]

[Table 5]

[0054]

[Table 6]

For example, in Example 2, the tensile strength is 8.0 k.
g / 2 mm × 2 mm, in Comparative Example 1, 3.2 kg /
It can be seen that there is a significant difference in the adhesion strength of 2 mm x 2 mm.
In addition, the co-sintered bodies according to all the examples have a front and back parallelism of 0.20 mm / diagonal line or less, which is small in warpage, and the conductor layers of the examples include various inorganic fillers. Comparative Example 4 containing no such inorganic filler
It can be seen that the resistivity of the conductor layer is lower than that of No. 7 as well.

In order to measure the relative density of the conductor layer after sintering, a press-molded body of the conductor layer composition is prepared so as to have the same green density as the paste when screen-printed, and a circuit board is prepared. The measurement was performed after sintering under the same conditions. The microstructures of both samples after sintering were observed and confirmed to have the same microstructure. As shown in Table 2, the measured values of relative density were found to be large and dense.

Further, the obtained circuit board was sealed with a high thermal conductive sealing member and a helium leak test was conducted. After the sealed sample was left in a chamber filled with helium gas at 5 atm for 40 minutes, the pressure in the chamber was reduced to the order of 10 ⁻³ torr and air was introduced up to 1 atm again. After performing this helium cleaning step three times, the sample was taken out of the chamber and left in the air for 30 minutes. After processing like this,
The amount of helium leak that was subjected to the helium leak test (detection of fine leak) was detected by a mass spectrometer.
As a result, it was less than 1.0 × 10 ⁻¹⁰ atm · cc · s ⁻¹ , which was a good value. Further, a gross leak test was conducted in which the above sample was placed in 3M Fluorinert No. 40 heated to 120 ° C. and left for 3 minutes. As shown in Table 2,
No bubbles were generated and no gross leak was confirmed.

Example 36 A 25 mm × 25 mm × 2.6 mm aluminum nitride multilayer circuit board having an internal wiring layer was prepared by using an insulating layer and a conductor layer having the same structure as in Example 1. 240 lead pins were joined to the other side of the aluminum nitride multilayer circuit board using silver solder. After that, the power consumption of the semiconductor element is 10
A W silicon element was bonded and mounted on the upper surface of the aluminum nitride multilayer circuit board, and a bonding wire was attached to complete electrical connection.

Further, an aluminum nitride sintered body having a thermal conductivity of 155 W / mK was used to produce a high thermal conductive sealing member which also serves as a heat radiating member in the same manner as the insulating portion of Example 1 was produced. Then, this sealing member is joined to the upper surface of the aluminum nitride multilayer circuit board by Au-Sn solder, and a radiation fin having a circular 7-step structure with a diameter of 25 mm is arranged on the sealing member to obtain a target semiconductor device. It was In order to evaluate the heat dissipation of this semiconductor device, the cooling air velocity was set to 1.5 m / s and the thermal resistance was measured by the ΔVBE method.
It was found that a semiconductor device having a low heat resistance value of ℃ / W and high heat dissipation can be obtained.

Comparative Example 8 A semiconductor device was manufactured in the same manner as in Example 36 except that the insulating layer and the conductor layer each having alumina as the insulating layer were used in Example 36. The thermal resistance value of this semiconductor device is 8.5 ° C.
/ W was significantly higher than that of Example 36.

[0061]

As described above, the AlN according to the present invention is
The ceramic circuit board has an insulator with high thermal conductivity, strong adhesion of the conductor layer and little deformation of the board during the sintering process, and the tensile strength shows a sufficiently practical characteristic value and is dense. It has various excellent properties such as low resistivity, and its industrial value is extremely large.

[Brief description of drawings]

FIG. 1 is a partially cutaway perspective view showing a multilayer ceramic circuit board according to the present invention.

FIG. 2 is a diagram showing a semiconductor device (when external terminals are lead pins) using a multilayer ceramic circuit board according to the present invention.

FIG. 3 is a partial cross-sectional view of a semiconductor device according to the present invention in which external terminals are solder balls.

[Explanation of symbols]

 1,12 Multilayer ceramic circuit board 2,14 Insulating layer 3 Conductor layer 4 Via hole 5 Radiating fin 6 Semiconductor element 7 Lead pin 8 Bonding wire 9 Conductor layer (internal wiring layer) 9a Via hole 10 Surface wiring layer 11 Wiring pattern 12a Substrate top surface 12b Substrate Lower surface 13 High thermal conductivity sealing member 13a Convex outer edge portion 13b Concave portion 15 Solder ball A Bonding surface

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Fumio Ueno 1 Komukai Toshiba-cho, Sachi-ku, Kawasaki-shi, Kanagawa Incorporated Toshiba Research and Development Center

Claims (6)

[Claims] 1. An insulator portion containing AlN as a main component, W,
At least a part of a conductor part containing at least one kind of Mo as a main component, one or more elements selected from the group consisting of Ni, Co and Fe, and further containing 0.1 to 20% by weight of AlN. A circuit board having: 2. The circuit board according to claim 1, wherein the conductor portion further contains one or more elements selected from the group consisting of alkaline earth elements and rare earth elements. 3. The conductor portion further contains alumina.
The described circuit board. 4. The relative density of the conductor portion is 93% or more,
The circuit board according to claim 1. 5. A semiconductor device in which a semiconductor element is mounted on the circuit board according to claim 1. 6. A conductor paste containing at least one of W and Mo as a main component, containing at least one element selected from the group consisting of Ni, Co and Fe elements, and containing AlN powder, A method for manufacturing an AlN circuit board, which comprises forming at least a part of a conductor portion and sintering at less than 1,600 ° C.