JPH0873285A - Glazed ceramic substrate and its production - Google Patents

Abstract

PURPOSE: To enable to control surface resistance and bake at a low temp. and to obtain a glazed ceramic substrate having further excellent surface smoothness by adding and dispersing a transition metal oxide in a glass matrix to form a glazing layer. CONSTITUTION: A paste for printing is obtained by blending (A) the transition metal oxide powder, which is made by mixing and calcining two or more kinds of the transition metal oxides and pulverizing the calcined body into 0.3-5.0μm in average particle diameter, with (B) a glass powder, which contains 20-50% B2 O3 , 5-35%, Al2 O3 , 15-55% alkaline earth oxide and <=40% SiO2 so as to be >=90% in the total on the basis of oxide weight as reference, in the ratio of A/B=3/97-40/60 and adding to mix an ethyl cellulose based binder and an organic solvent. The glazed ceramic substrate having the glazing layer made by dispersing the transition metal oxide phase in the glass matrix is obtained by applying the paste on the ceramic substrate and baking at a lower temp. than the melting temp.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a graded ceramic substrate suitable for an electronic circuit board having wirings formed by thin film technology, thick film technology, or a combination thereof, and a method for manufacturing the same. More specifically, it has wiring on the upper layer and / or lower layer of the glaze, and further has various functional parts,
The present invention relates to a graded ceramic substrate suitable for forming a hybrid circuit having a capacitor, a resistor, an inductor, etc., and a method for manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, a graded ceramic substrate has been known as a substrate whose surface smoothness is remarkably improved. Since this graded ceramic substrate has excellent surface smoothness of glass as well as excellent heat storage and electrical insulation properties, it is used in various thermal heads, for example, by making use of its characteristics.

[0003] gray - Zudo ceramic substrate, Sa - thermal head other electronic component applications, in particular also used for thin film hybrid substrate, in recent years the application of this _{field, B 2 O 3 -Al 2 O} 3 as a particularly preferred material A low melting point glaze composition such as an alkaline earth oxide-SiO ₂ system has been proposed (JP-A-6-191883). In addition, a polyimide resin multilayer substrate having excellent electrical insulation properties is used for applications that do not require as high heat resistance as glass.

[0004]

SUMMARY OF THE INVENTION Capacitors and resistors using a thin film process have been developed in response to recent demands for higher functionality, higher speed, smaller size, higher accuracy and improved reliability of electronic devices and electronic components. An electronic circuit board incorporating a functional circuit such as an inductor is desired. By the way, conventionally, as a thin film substrate, a ceramic polishing substrate or a substrate in which a glaze layer or a polyimide layer is formed on the surface of the ceramic substrate is used. Depending on the application, these thin film substrate materials may have an adverse effect on the circuit function due to the accumulation of electric charges in the functional circuit section or the like. In order to prevent such electrification, there is a method in which the surface resistance of the substrate material surface is lowered and a slight leakage current is generated. However, even if the resin composition of the polyimide layer and the glass composition of the glaze layer are changed,
It was difficult to control electrical characteristics such as optimizing the surface resistance value that causes a slight leakage current.

In addition to the above, when wiring is first formed on the substrate (primary metallization) and then over-graded,
In order to meet the demand for multi-layering with primary metallization, it is necessary to keep the baking temperature of the glaze low so as not to affect the primary metallization layer during the glaze baking. Furthermore, since it is necessary to form highly accurate wiring on the glaze layer, surface smoothness equivalent to that of the conventional glaze layer and polyimide layer is also required.

[0006]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and is suitable for forming thin film functional circuits such as capacitors, resistors and inductors.
It is an object of the present invention to provide a sud ceramic substrate and a method for manufacturing the same, and particularly to prevent an obstacle to a circuit function due to charging.

In order to achieve this object, the invention of claim 1 has an average particle diameter of 0.3 to 5.0 μm in a glass matrix.
A glazed ceramic substrate is characterized in that it has a glaze layer in which a transition metal oxide phase of m is dispersed.

As a further limitation of the invention of claim 1, in the invention of claim 2, the weight ratio of the glass matrix to the transition metal oxide phase is 97: 3 to 60: 4.
It is characterized by being in the range of 0. The invention of claim 3 is
At least a part of the transition metal oxide phase is a transition metal composite oxide containing two or more kinds of transition metals. In the invention of claim 4, the glass matrix is based on the weight of the oxide, B ₂ O ₃ : 20 to 50% and Al ₂ O ₃ : 5 to 35%.
And, an alkaline earth oxide: 15 to 55% and, Si0 _2:
40% or less, and the total of these is 90% or more.

According to a fifth aspect of the invention, a step of mixing two or more kinds of transition metal compounds and calcining the mixture to form a calcined body of a transition metal composite oxide containing two or more kinds of transition metals, and the calcining. By crushing the body, the average particle size is 0.3-5.0μ
a step of forming a transition metal complex oxide powder of m, a step of forming a printing paste composed of the transition metal complex oxide powder and a glass powder, and a step of coating and baking the paste on a ceramic substrate. A gist of the method for manufacturing a graded ceramic substrate is characterized by the following. .

According to the invention of claim 6, a step of forming a mixture of glass powder and a transition metal oxide powder or a transition metal double oxide powder having an average particle diameter of 0.3 to 5.0 μm, and the mixture is a glass powder. A step of forming a glass gob which is melted at a temperature at which is melted and a transition metal oxide phase is dispersed therein, a step of crushing the glass gob into a glass powder having an average particle diameter of 10 μm or less, A gist of a method for producing a graded ceramic substrate is characterized by including a step of coating on a ceramic substrate and baking at a temperature lower than a melting temperature.

The ceramic substrate is not particularly limited as long as it is a ceramic substrate, and alumina, silicon nitride, aluminum nitride, silicon carbide, mullite, crystallized glass and the like can be widely used.

The reasons why the glazed ceramic substrate of the present invention and the method for manufacturing the same are limited as described above will be described below. The average particle size of the transition metal oxide added to the glass matrix is set to 0.3 to 5.0 μm, because when the average particle size is less than 0.3 μm, bubbles do not escape in the glass matrix when the glaze is baked. Air bubbles remain,
This is because variations in electrical characteristics will occur as a result. At the same time, the force for crystallizing the glass matrix becomes stronger, which hinders the densification of the glaze layer. on the other hand,
This is because when the average particle diameter exceeds 5 μm, a convex portion made of a transition metal oxide is formed on the glaze surface to deteriorate the smoothness. The average particle size of the transition metal oxide is 0.4 to
3.5 μm is more preferable.

The weight ratio of the glass matrix to the transition metal oxide phase is in the range of 97: 3 to 60:40, because the transition metal oxide phase of less than 3% can exert an effect on electrical characteristics. If it exceeds 40%, the insulating property is extremely deteriorated, and since the amount of the additive is large relative to the glass matrix, the surface smoothness is deteriorated. In particular, when the weight ratio is 95: 5 to 80:20, it is more preferable in terms of electrical characteristics and surface smoothness. Further, it is preferable to use a transition metal complex oxide prepared by calcination, because changes in electrical characteristics such as a decrease in surface resistance value due to the addition of the transition metal oxide are stably exhibited. Further, when the transition metal oxide and the transition metal double oxide are added in the same amount for comparison, the addition of the transition metal double oxide is preferable because the surface resistance value is largely decreased and the surface roughness is small.

The composition of the glass matrix is 10
It is not particularly limited as long as it can be baked at 00 ° C or lower.
However, alkaline earth borosilicate glass containing no alkali metal or lead (alkaline earth-boric acid-silica glass) is preferable. This is because glass containing an alkali metal or lead has high fluidity and has good wettability with the transition metal oxide particles, but the transition metal oxide particles are easily eroded and dissolved, and are easily lost. This is because the surface resistance value is likely to vary.

Particularly preferably, a glass system containing no alkali metal or lead, containing a large amount of B ₂ O ₃ , Al ₂ O ₃ and containing an appropriate amount of SiO ₂ . The glass system is appropriately wet with the transition metal oxide and has a good compatibility therewith, and thus forms a dense glaze layer without forming bubbles (voids). Further, the transition metal oxide is not dissolved too much, the dispersibility of the transition metal oxide is good, and the surface resistance value becomes stable.
Moreover, even if the transition metal oxide is partially dissolved in the glass,
A good surface condition is obtained without crystallizing the glass.
As such a glass system, for example, on the basis of oxide weight,
B ₂ O _3: and _{20~50%, Al 2 O 3:} 5~35% and alkaline earth oxides (MgO, CaO, SrO, Ba
O): and 15 to 55%, Si0 _2: and a 40% or less, there is a glass material these sum is 90% or more, further ZnO as the minor component, such as _{P 2 O 5, V 2 O} 5 You may add. Such a glass composition has a low melting point, has little reaction with the primary metallized layer, and can be formed into a multilayer structure.
And shows good surface smoothness.

[0016]

The transition-metal oxide-added graded ceramic substrate of the present invention is significantly different in electrical characteristics from the conventional graded ceramic substrate. That is,
When a thin film functional circuit is formed, it is a graded ceramic substrate capable of causing a slight leakage current between the circuits to prevent charging and thus prevent the occurrence of defects due to charging of the circuit section. An appropriate surface resistance value for generating a slight leakage current to the extent that this charging is prevented is 10 ⁵ to 10 ¹¹
Ω is preferable, and 10 ⁸ to 10 ¹⁰ Ω is more preferable.

In order to exert the above characteristics, a proper degree of dispersion of the transition metal oxide and the glass matrix is important,
The transition metal oxide acting as a conductor or a semiconductor can be uniformly distributed in an electrically insulating glass matrix in an appropriate size and amount to achieve desired electrical characteristic values and surface smoothness. It seems to be.
In particular _{B 2 O 3 -Al 2 O 3} - alkaline earth oxides -Si0 ₂
Since the low melting point glaze composition of the system has appropriate wettability with the transition metal oxide particles, it is considered that a good glaze layer with few defects such as bubbles can be obtained.

[0018]

EXAMPLES Examples of the graded ceramic substrate and the manufacturing method thereof within the scope of the present invention will be described below, and those outside the scope of the present invention will also be described as comparative examples. Examples 1 to 4 Each transition metal oxide is prepared so as to have the transition metal oxide composition of Examples 1 to 4 in Table 1 and Table 2.

[0019]

[Table 1]

[0020]

[Table 2]

The mixture of each transition metal oxide was wet pulverized by a pot mill to obtain a transition metal oxide powder having an average particle diameter of 0.4 to 3.8 μm. B ₂ O _{3 by} weight composition: 27%,
Al ₂ O ₃ : 26%, SiO ₂ : 15%, CaO: 14
%, SrO: 4%, BaO: 14%, a glass composition powder having an average particle diameter of 3.1 μm and a transition metal oxide powder in a weight ratio (glass composition: transition metal oxide) of 90:
The mixture was wet mixed in a pot mill at a ratio of 10 and an ethyl cellulose binder and an organic solvent were added and mixed to prepare a glass paste for printing to which a transition metal oxide was added. A glass paste to which this transition metal oxide was added was made of Al ₂ O ₃ having a purity of 97% and was 50 mm × 50 mm ×
850 after printing on the surface of 0.635mm alumina substrate
It was baked at 10 ° C. for 10 minutes to prepare a glazed ceramic substrate having a glaze thickness of 20 μm. Also, in order to measure the surface resistance value, a wiring pattern of a predetermined shape was used.
A Ti-Cu thin film was formed by a ring method, and then Ni plating was performed to manufacture the film, and the surface resistance value was measured. Then, in the conventional glaze, which was> 10 ¹⁷ Ω, is 10 ^{9 in} all cases.
Ω, and a clear resistance reduction effect was confirmed. The smoothness of the glaze surface was good (Ra ≦ 0.1 μm), and the color was gray to black. When the phase analysis of the glaze part was performed by X-ray diffraction analysis, the transition metal oxide phases added were confirmed.

Examples 5 to 9 Each transition metal oxide was prepared so as to have the composition of the transition metal oxides of Examples 5 to 9 shown in Tables 1 and 2, and wet-ground to make a transition having an average particle diameter of 1.2 μm. A metal oxide powder was used. By weight composition, B ₂ O ₃ : 27%, Al ₂ O ₃ : 26%, SiO ₂ : 15
%, CaO: 14%, SrO: 4%, BaO: 14%, and a transition metal oxide powder in a weight ratio (glass composition: transition metal oxide) of 97: 3,9.
Wet-mixing in a pot mill at a ratio of 5: 5, 80:20, 70:30, 60:40, adding an ethyl cellulose-based binder and an organic solvent, mixing and adding a transition metal oxide for printing. A glass paste was prepared. The glass paste added with the transition metal oxide had a purity of 97%.
After printing on the surface of an alumina substrate of 50 mm × 50 mm × 0.635 mm made of Al ₂ O _{3 of the above,} it was baked at 850 ° C. for 10 minutes to prepare a graded ceramic substrate having a thickness of 20 μm. As a result of measuring these surface resistance values, a clear resistance reduction effect was confirmed, which was 10 ⁵ to 10 ¹¹ Ω. Also, the smoothness of the glaze surface is good (Ra ≦
0.1 to 0.2 μm) and the color was gray to black.

[0023]

[Figure 1]

FIG. 1 shows a backscattered electron beam image of the fractured surface of the glaze portion of the glazed ceramic substrate of Example 7. The white part is the transition metal oxide phase and the black part is the glass matrix. From the photograph, it can be seen that the transition metal oxide phase having a size of 1 to 2 μm is uniformly dispersed in the glass matrix.

Examples 10 to 12 Each transition metal oxide was prepared so as to have the transition metal oxide composition of Examples 10 to 12 in Tables 1 and 2. This formulation was wet mixed and then calcined at 1200 ° C. for 1 hour to obtain a transition metal composite oxide. The generation of the transition metal complex oxide was subjected to confirmed by X-ray diffraction analysis, NiCr ₂
O ₄ , FeCr ₂ O ₄ , CoCr ₂ O ₄ , NiFe ₂ O ₄ , C
Formation of complex oxides containing two or more transition metals such as oFe ₂ O ₄ and Fe ₂ TiO ₅ was observed. The obtained calcined product was wet pulverized by a pot mill to have an average particle size of 2.1 to 3.5.
After forming the transition metal mixed oxide powder having a size of μm, a graded ceramic substrate was prepared in the same manner as in Example 1. As for the glaze layer, the surface resistance value was measured, and as a result, a clear resistance reducing effect of 10 ⁹ Ω was confirmed. The smoothness of the glaze surface was Ra ≦ 0.1 μm, which was good. Further, the glaze portion was subjected to a phase analysis by X-ray diffraction analysis, and as a result, a transition metal complex oxide phase produced by calcination was confirmed.

Examples 13 to 15 Each transition metal oxide was prepared so as to have the transition metal oxide composition of Examples 13 to 15 in Tables 1 and 2. This formulation was wet-milled with a pot mill and then calcined at 1200 ° C. for 1 hour. This was wet pulverized in a pot to obtain a transition metal composite oxide powder having an average particle diameter of 2.1 μm. By weight composition, B ₂ O ₃ : 27%, Al ₂ O ₃ : 26%, SiO ₂ : 15
%, CaO: 14%, SrO: 4%, BaO: 14%, and a transition metal complex oxide powder.
95: 5 by weight ratio (glass composition: transition metal oxide),
A mixture of 90:10 and 80:20 was used as 90% mixture.
The glass portion was remelted by heat treatment at 0 ° C. for 30 minutes, quenched, wet-ground in a pot mill and dried to have an average particle size of 3 μm. An ethyl cellulose-based binder and an organic solvent were added thereto and mixed to prepare a glass paste for printing in which a transition metal complex oxide was added. The glass paste added with the transition metal complex oxide was treated with Al having a purity of 97%.
After printing on the surface of an alumina substrate of ₂ O _{3 having a} size of 50 mm × 50 mm × 0.635 mm, it was baked at 850 ° C. for 10 minutes to prepare a glazed ceramic substrate having a glaze thickness of 20 μm. As a result of measuring the surface resistance value of this glaze layer, a clear resistance reduction effect of 10 ⁷ to 10 ¹⁰ Ω was confirmed. The smoothness of the glaze surface was Ra ≦ 0.07 μm, which was much better than that of the same composition in which the pores were small and the glass portion was not remelted.

[0027]

[Comparative example]

Comparative Example 1 A glass paste for a grade was produced without adding a transition metal oxide only with the glass composition of Example 1, and a graded ceramic substrate was produced under the same conditions as in Example 1 except for the above. did. The glaze portion had a surface resistance value of 10 ¹⁷ Ω or more, and had a high insulating property.

Comparative Examples 2 and 3 Each transition metal oxide was prepared so as to have the transition metal oxide composition of Comparative Examples 2 and 3 in Tables 1 and 2. This preparation was wet-milled with a pot mill to obtain a transition metal oxide powder having an average particle diameter of 1.2 μm. The weight ratio (glass composition: transition metal oxide) of this transition metal oxide powder to the glass composition powder of Example 1 was 99.5: 0.5 and 5.
A graded ceramic substrate was manufactured under the same conditions as in Example 1 except that the ratio was 0:50. Glass composition of Comparative Example 2:
The surface resistance of the transition metal oxide having a weight ratio of 99.5: 0.5 was measured. As a result, it was 10 ¹⁶ Ω which was comparable to that of the conventional glaze, and the effect of reducing the resistance was hardly seen. . On the other hand, in Comparative Example 3 in which the weight ratio was 50:50, the surface resistance was less than 10 ⁵ Ω and the insulating property was poor, and the surface roughness was Ra> 0.3 μm, and the desired smooth glaze surface was not obtained. It was

Comparative Examples 4 and 5 Each transition metal oxide was prepared so as to have the transition metal oxide composition of Comparative Examples 4 and 5 in Tables 1 and 2. This formulation was wet mixed and then calcined at 1200 ° C. for 1 hour to partially form a transition metal composite oxide. The obtained calcined product was wet pulverized by a pot mill to obtain an average particle size of 0.15 μm and 7.
Two kinds of transition metal complex oxide powder having a size of 0 μm were used. A graded ceramic substrate was produced under the same conditions as in Example 1 except that the transition metal composite oxide having an average particle diameter of 0.15 μm and 7.0 μm was used. In Comparative Example 4 in which a transition metal complex oxide having an average particle diameter of 0.15 μm was added, pores inside the glaze became remarkable and the glass matrix could not be densified, and the glass matrix seemed to be partially crystallized. Further, in Comparative Example 5 in which a transition metal composite oxide having an average particle diameter of 7.0 μm was added, a sufficient smooth surface could not be obtained due to the protrusions caused by the transition metal oxide particles.

Comparative Example 6 B ₂ O ₃ : 2% by weight composition, Al ₂ O ₃ : 7 by weight of glass composition
%, SiO ₂ : 58%, CaO: 2%, SrO: 24
%, BaO: 4%, Y ₂ O ₃ : 3%, and a baking temperature of 1250 ° C., which is suitable for this glass composition, except that a graded ceramic substrate was produced under the same conditions as in Example 2. . The state of the glaze surface is due to foaming that is thought to be caused by the transition metal oxide generated during baking,
The smoothness of the surface was lost (Ra> 1.0 μm). still,
Even when the mixture of the glass composition and the transition metal oxide was fired at 850 ° C. as in Example 2, the glass composition was not softened and adhered to the ceramic substrate.

[0031]

As described above, the transition metal oxide-added graded ceramic substrate of the present invention is capable of controlling the electrical characteristics, that is, the surface resistance value, and can be baked at a low temperature. Furthermore, it has good surface smoothness. Therefore, it is suitably used as an electronic circuit substrate on which functional circuits such as various capacitors, resistors, and inductors are formed of thin films.

[Brief description of drawings]

FIG. 1 is a photograph of a backscattered electron beam image showing a structure of a fractured surface of a glaze portion of a glazed ceramic substrate of Example 7.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Masahiro Kato 14-18 Takatsuji-cho, Mizuho-ku, Nagoya-shi, Aichi Nihon Special Ceramics Co., Ltd. (72) Inventor Keisho Hiraoka 14-takatsuji-cho, Mizuho-ku, Nagoya, Aichi No. 18 Nihon Special Ceramics Co., Ltd.

Claims (6)

[Claims] 1. An average particle diameter of 0.3 in a glass matrix.
~ 5.0 μm transition metal oxide phase dispersed
A glazed ceramic substrate having a glazing layer. 2. The graded ceramic substrate according to claim 1, wherein the weight ratio of the glass matrix to the transition metal oxide phase is in the range of 97: 3 to 60:40. 3. The graded ceramic substrate according to claim 1, wherein at least a part of the transition metal oxide phase is a transition metal double oxide containing two or more kinds of transition metals. 4. The glass matrix comprises, based on the weight of oxide, B ₂ O ₃ : 20 to 50% and Al ₂ O ₃ : 5 to 35%.
And, an alkaline earth oxide: 15 to 55% and, Si0 _2:
40% or less, and the total of these is 90% or more, The graded ceramic substrate of Claim 1 characterized by the above-mentioned. 5. A step of preparing a calcined body of a transition metal composite oxide containing two or more kinds of transition metals by mixing and calcining two or more kinds of transition metal compounds, and crushing the calcined body. A transition metal complex oxide powder having an average particle diameter of 0.3 to 5.0 μm, a printing paste comprising the transition metal complex oxide powder and a glass powder, and
A step of applying a strike on a ceramic substrate and baking it. 6. Glass powder and average particle diameter 0.3 to 5.0
a step of forming a mixture consisting of a transition metal oxide powder or a transition metal double oxide powder of μm, and a step of forming a glass mass in which the mixture is melted at a temperature at which the glass powder melts and the transition metal oxide phase is dispersed, A step of crushing the glass gob into a glass powder having an average particle diameter of 10 μm or less; and a step of applying a paste made of the glass powder on a ceramic substrate and baking at a temperature lower than the melting temperature. -A method for manufacturing a pendant ceramic substrate.