JPH0483737A - Dielectric porcelain composition, production thereof and basal plate for distributing board using said composition - Google Patents

Abstract

PURPOSE:To enable incorporation of a conductor having a small conducting resistance, a high dielectric constant and a small temperature coefficient by firing a powdery mixture composed of a glass having a corderite-based composition and TiO2. CONSTITUTION:With 100 pts.wt. powdery mixture between 70-100 wt.% corderite-based glass composed of 25-65wt.% SiO2, 7-25wt.% MgO, 10-45wt.% Al2O3 and 1-20wt.% B2O3 and having <=20mum particle size and 0-30wt.% TiO2 having<=2m<2>/g BET specific surface area,<30 pts.wt. powdery filler (eg alumina) having<=30 dielectric constant is blended as necessary. The resultant mixture is formed into a desired shape, densified to <=6% air void content by firing at 800-1100 deg.C and subsequently subjected to crystallization treatment at 850-1100 deg.C, thus giving the objective dielectric porcelain composition containing TiO2 particles dispersed in the resultant corderite crystalline matrix layer.

Description

Detailed Description of the Invention (Technical Field) The present invention relates to a dielectric ceramic composition, a method for manufacturing the same, and a wiring board using the same, and particularly relates to a high frequency integrated circuit (MIC).
The present invention relates to a high-frequency dielectric ceramic composition suitable for wiring boards, etc., a method for manufacturing the same, and a wiring board obtained using the same.

(Background Art) With the development of high frequency devices such as mobile phones, the MICs used in these devices are also required to be small and have high performance. The dielectric ceramic required for such a MIC wiring board is required to have the following characteristics. That is, first, (1) relative dielectric constant (εr)
is high. When this dielectric constant is high, it becomes possible to miniaturize the resonant circuit, inductance, and capacitor when used at a fixed frequency. Also, (2) the Q value is high. If the Q value of ceramics is high, it is possible to increase the Q value of a resonant circuit or inductance using the ceramic.

Furthermore, (3) the temperature coefficient of the dielectric constant and the temperature coefficient of the resonant frequency of the formed resonant circuit are small.

and (4) conductor wiring can have a multilayer structure. Also, (5) the resistance of the conductor is low. This is because if the resistance of this conductor is large, the Q value of the resonant circuit and inductance will be small, and the transmission loss of the conductor line will be large.

By the way, as a dielectric ceramic composition of this kind, for example, Japanese Patent Publication No. 5E120905 discloses Ba0
-TiO
(Mg + 7: + Tazz 3) 03 and other compositions with a composite perovskite structure were further developed by
No. 5678 discloses Ti0z-ZrOz-3nOz
In addition, Japanese Patent Publication No. 56-26321 discloses Ba0-Tie, or a part of which is substituted with another element.
□RE20. (RE: rare earth metals) have been clarified.

However, although these conventional dielectric ceramic compositions have a high dielectric constant, when trying to provide a multilayered conductor path inside them in order to obtain the intended wiring board, it is difficult to use conductive paths such as Pt or Pd as a conductor. There was a problem that only large conductor materials could be used. Such dielectric ceramic compositions have a high firing temperature, so they are made of Ag-based or Cu-based materials, which have a low melting point.
This is because it is not possible to use conductor materials with low conduction resistance, such as conductor materials such as AU series or AU series.

In addition, low-cost dielectric ceramic compositions made of ceramics such as alumina, steatite, or forsterite are known, but these have large temperature coefficients and it is difficult to provide conductor paths in a multilayer structure. Then,
For the same reason as mentioned above, there is an inherent problem in that only conductive materials with high conduction resistance, such as Pt, Pd, W, and Mo, can be used.

(Problem to be Solved) The present invention has been made against this background, and its object is to provide a conductor with a large dielectric constant, a small temperature coefficient, and a small conduction resistance. The object of the present invention is to provide a dielectric ceramic composition that can be built-in, a method for manufacturing such a dielectric ceramic composition, and furthermore a wiring board using such a dielectric ceramic composition. There is a particular thing.

(Solution Means) In other words, in order to solve the problem, the present invention was completed based on the facts found as a result of various studies on the composition of many dielectric ceramics, and the gist thereof is as follows. , cordierite composition glass and Ti
The mixed powder with O□ is fired to produce a dielectric ceramic composition in which the TiO□ particles are dispersed in the resulting cordierite crystalline matrix, and the glass and TiO□ are combined according to the following formula: The dielectric ceramic composition is characterized in that it is used in a proportion that satisfies the following formula: % by weight of χ Nigarasu y: % by weight of Tio □.

In addition, in the present invention, in order to obtain such a dielectric ceramic composition, a mixed powder obtained by uniformly blending two components in the above-mentioned proportions is used, and a molded body formed from this mixed powder is used. , sintering at a temperature of 1100"C or less to densify the glass component and crystallize the glass component having a cordierite composition to produce a cordierite crystalline phase as a parent phase in the resulting dielectric ceramic composition. It is a feature.

Furthermore, the present invention uses the ceramic (dielectric ceramic composition) obtained as described above as a dielectric, and in this dielectric,
Another object of the present invention is a wiring board having at least one conductor track built therein.

In addition, in the mixed powder for producing such a dielectric ceramic composition, if necessary, filler powder having a dielectric constant of 30 or less may be added in a proportion not exceeding 30 parts by weight in total to 100 parts by weight. It will be further blended in.

(Specific configuration) By the way, the mixed powder for providing the dielectric ceramic composition according to the present invention is composed of cordierite-based glass and TiO
It is necessary to mix the two components (□) in a ratio that satisfies the first two, and if it deviates from this range, the object of the present invention cannot be fully achieved. That is, the proportion (1% by weight) of glass powder having a cordierite composition is 7.
On the other hand, if the proportion of T i O2 powder (7% by weight) exceeds 30% by weight, it becomes difficult to sinter the mixed powder at a sintering temperature of 1100"C or lower. This makes it difficult to achieve sufficient densification, and even more difficult to crystallize.

In the present invention, the glass having a dark cordierite composition is used to impart the excellent microwave dielectric properties of cordierite to the obtained dielectric porcelain composition and to obtain low-temperature sinterability. Therefore, as long as the main crystal is cordierite, it is basically possible to use various known glasses with cordierite compositions without any problem. However, in the present invention, SiO□:2
5-65% by weight, MgO near-25% by weight, A A 2
03: 10-45% by weight, B2O3: 0-20% by weight
A glass having the following composition is advantageously used. This is because by employing SiO□, MgO, AlzO:+ within such a range, firing and densification at 1100°C or less can be performed more effectively, and also when the proportion of B2O3 is 2.
This is because if it exceeds 0% by weight, the water resistance of the sintered body will deteriorate. In addition to these components, alkali metal oxides, alkaline earth metal oxides, ZrOz
, ZnO1PbO, etc., as necessary, to improve sinterability, Mn, Cr, Fe, C
o.

Oxides of Ni, Cu, and rare earth metals may be added as glass components to provide color, and TiOz may also be added to the glass component as a nucleating agent to promote crystallization. In addition to such glass components, a certain amount of impurities are also mixed in, considering the glass manufacturing process.

Note that such cordierite composition glass can be prepared by various known vitrification methods, and usually a mixture is prepared by blending each raw material component in a ratio that gives the desired cordierite composition. Obtained by melting, rapidly cooling the melt and vitrifying it,
It is then crushed and used. In addition, in order to improve the sinterability of such glass powder having a cordierite composition, it is desirable to reduce its particle size, and it is generally used as a powder with a particle size of 20 μm or less, particularly about 1 to 10 μm. is desirable.

Further, in the present invention, TiOz is added to change the dielectric constant and temperature coefficient of resonance frequency of the obtained dielectric ceramic composition. By adding this TiO□, the temperature coefficient of the resonance frequency changes to the positive side depending on the amount added. Therefore, if the dielectric ceramic composition consists only of cordierite composition, the temperature coefficient of its resonance frequency will be approximately -80 to -40 ppm/'C, but by adding TiO7, It is possible to increase the temperature coefficient and further increase it to the positive side. Furthermore, since T i O2 has a large dielectric constant of about 100, the dielectric constant of the dielectric ceramic composition can be increased by adding it.

In addition, since such T i Oz powder is usually very fine, it tends to interfere with the sinterability of glass having a cordierite composition, and therefore, such T i O2
When adding more than 15% by weight, it is desirable to calcinate the particles in advance to increase the particle size. For example, such calcination produces particles with a BET specific surface area of about 2 m2/g or less.

The present invention uses such a mixed powder of cordierite-based glass and T i O2 in a predetermined ratio to obtain the desired dielectric ceramic composition. If necessary, it is possible to further mix a predetermined filler powder. Examples of such filler powders include alumina, quartz, mullite forsterite, and quartz glass. Among them,
Crystalline materials with a dielectric constant of 30 or less, such as alumina, quartz, mullite, and forsterite, have a small dielectric constant, so
Even if added, the permittivity of the resulting dielectric ceramic composition cannot be greatly increased, but alumina can increase the strength, and quartz, mullite, and forsterite can adjust the coefficient of thermal expansion. It will be added as needed, starting from where it can be made. Furthermore, a glass with high fire resistance such as quartz glass can be treated in the same manner as a crystalline glass having a dielectric constant of 30 or less. The amount of such filler powder to be added is such that the total amount thereof is 30 parts by weight or less based on 100 parts by weight of the mixed powder. This is because, if the blending amount of such filler powder increases, sufficient densification will not occur at temperatures below 1100''C.

In the present invention, the glass having a cordierite composition and the Tie are blended in a predetermined ratio in this manner, and if necessary, a predetermined filler powder is added to uniformly blend the resulting product. Using the mixed powder, the mixed powder is molded according to a conventional method, and a molded body is fired to make it densified, and the glass component having a cordierite composition is further crystallized to generate a cordierite crystalline phase. As a result, a dielectric ceramic composition in which TiO□ particles are dispersed and present in the cordierite crystalline matrix thus produced is obtained.

In this firing operation, a firing temperature of 1100'C or lower is employed, and the firing is densified, resulting in a dense sintered body with a porosity of generally 6% or lower. Further, the lower limit of the firing temperature is about 800°C. Further, the crystallization of the glass component having a cordierite composition in the sintered body can be carried out simultaneously with or subsequent to the firing operation by maintaining the glass component at the firing temperature. The temperature for this crystallization is 850
A temperature of about 1100°C is used. and,
By crystallizing the glass component having a cordierite composition, the desired dielectric porcelain composition, that is, a porcelain in which TiO□ particles are dispersed in a cordierite crystalline matrix can be obtained. be. Of course, the main crystal produced by crystallization of a glass component with a cordierite composition is cordierite, but depending on the composition of the glass, crystals such as mullite forsterite and spinel may also precipitate, and some non-woven crystals may also precipitate. It is inevitable that a crystalline phase remains.

In addition, in the present invention, when manufacturing a wiring board using the above dielectric ceramic composition as a dielectric, a mixed powder of the above-mentioned cordierite composition glass and TiO□ in a predetermined ratio is used. This is carried out in the same manner as before, but in -i, a green sheet obtained from such mixed powder is used, and conductor paths in a predetermined pattern are formed on it by a method such as printing using an appropriate conductor paste. On the other hand, the intended wiring board can be obtained by laminating such green sheets, forming a negative body, and simultaneously firing the green sheets and the conductor paths (conductor paste). In particular, in the present invention, since the green sheet using the mixed powder can be fired and further crystallized at 1100"C or lower, AgAg-Pt, Ag-Pd, Ag-Pt can be used as the conductor. -P
d etc., various known Cu-based conductors, and even A
A such as u, Au-Pt, Au-Pd, Au-Pt-Pd, etc.
U-based conductors can be used.

Therefore, such Ag-based, Cu-based, and Au-based conductors with low conduction resistance do not melt under firing conditions of 11.00"C or less, and can be fired simultaneously with the dielectric ceramic composition. This makes it possible to incorporate a low-resistance conductor.

FIG. 1 shows an example of the cross-sectional structure of the wiring board thus obtained. In this case, 2 is a glass having a cordierite composition and a tie.

This is a dielectric body made of a dielectric ceramic composition formed from a mixed powder of
For example, an integrated conductor track 4 located in its interior, a surface conductor track 6 located on its surface, and also a ground conductor track 8 are provided in stacked form. Further, a resistor 10 is also provided inside and outside the dielectric 2, as in the conventional case.

In the wiring board having such a structure, in the present invention, a mixed powder that can be fired and crystallized at 1100°C or less is used as the material for providing the dielectric 2, so that the conductor paths ( As the material of 4,6°8), a low melting point conductor with low conduction resistance, such as an Ag-based conductor or a Cu-based conductor, can be used and co-fired together with the dielectric 2.
Thus, a wiring board incorporating low-resistance conductor paths (4, 8) can be advantageously realized.

(Examples) Examples of the present invention are shown below to clarify the present invention more specifically, but the present invention is not limited in any way by the description of such examples. That goes without saying.

In addition to the following examples and the above-mentioned specific description, the present invention includes various changes, modifications, and changes based on the knowledge of those skilled in the art, as long as they do not depart from the spirit of the present invention. It should be understood that improvements and the like may be made.

Example 1 Magnesium oxide (MgO), quartz (SiO□),
Component raw materials such as alumina (Ai!, 203) and boric acid (H, BO,) were each weighed and thoroughly mixed in an alumina mortar. Next, the obtained mixture was melted at a temperature of 1600° C. in a platinum crucible, and then poured into water to be rapidly cooled to obtain glasses having various cordierite compositions. Thereafter, the glasses were wet-pulverized using an alumina pot and an alumina ball, dried, and measured in the range shown in the dielectric table below, and the results are shown in table 2 below. Note that the measurement frequency was 8 to 12 GHz.

Further, in Table 2, Q is converted into a value in IOc; Hz.

As is clear from the results in Table 2, all dielectric ceramic compositions No. 1 to 27 according to the present invention were densified by firing at a temperature of 900 to 1000°C. It is recognized that the dielectric constant, no-load Q, and temperature coefficient (τ) of the resonant frequency can be improved. On the other hand, comparative examples No. 28 and No.
, 29, 900 to 100
The various cordierite-based composition glass powders and TiO□ powder obtained in this way at a firing temperature of 0°C were weighed so as to have the weight ratio shown in Table 2 below, and polyethylene bottles and Each was wet mixed using an alumina ball. This obtained mixture was then
After drying, PVA was added as a binder, mixed well, and granulated by passing through a 40-mesh sieve. Each of the various powders prepared in this way was molded using a press molding machine under a surface pressure of 1 ton 7.
In cm2, 20++.

A disk-shaped sample with a size of φX12+11111t was molded. Next, each sample molded in this way was heated in air at a temperature of 900 to 1000°C.
It was baked for 30 minutes. Furthermore, each sample obtained by firing was polished to a size of 16 mmφ×8 circles 5.

The permittivity and unloaded Q of the various samples obtained in this way were measured by the well-known parallel conductor plate type dielectric resonator method, and the temperature coefficient of the resonant frequency (
τ,) at -25°C to 75°C Example 2 A mixed powder having the composition of dielectric porcelain N027 in Table 2 in Example 1 was used, along with an acrylic organic binder, a plasticizer, toluene, and alcohol. A green tape having a thickness of 0.1+11111 to 1.0M was produced from this slurry by a doctor blade method.

On the other hand, Ag-based powder, acrylic-based organic binder, and terpineol-based organic solvent were thoroughly kneaded using a mixer using three rollers to prepare a conductive paste for printing.

Note that a commercially available resistor paste for thick film circuits was prepared.

Next, a conductor wiring pattern, a ground layer, and a resistor were printed on the green tape using these pastes. In addition, following the principles of capacitor patterns and distributed constant circuits, conductor patterns were printed to create stripline and ring-type resonant circuits and inductances. Then, after stacking the green tapes with these conductor patterns printed on them in a predetermined order, they were heated at a temperature of 100°C for 10 minutes.
A pressure of 0 kg/cm was applied to integrate the layers.

Note that connection between each conductor layer was achieved by filling conductor paste into through holes formed in the green tape by punching or the like. After that, such a laminated body is heated at 50°.
After removing the binder at a temperature of C, it was fired at 900° C. for 30 minutes, and at the same time, the glass component having a cordierite composition was crystallized to obtain a wiring board having a structure as shown in FIG.

The conductor pattern on the surface of the wiring board obtained in this way is made by printing a new conductor paste for the surface pattern after baking the board, taking into account pattern accuracy, adhesive strength, and solder resistance. It was formed by In this case, the conductor paste for the surface is a commercially available A for thick film circuits.
A g/Pt system or an Ag/Pd system was used, and a commercially available Cu paste was also used.

In this way, it is possible to obtain a wiring board for an MIC circuit in which a resonant circuit and a capacitor are built inside the board.Moreover, in such a board, since the resistance of the conductor (Ag type) is low, a resonant circuit with low loss, A transmission line with small capacitors, inductance, and transmission loss can be obtained, and this allows multilayer M with extremely excellent high frequency characteristics.
We were able to create an IC board.

(Effects of the Invention) As is clear from the above description, the present invention provides a dielectric ceramic composition that has a large dielectric constant, a small temperature coefficient, and is capable of incorporating a conductor with a small conduction resistance. Furthermore, since the cordierite-based ceramic that mainly constitutes such a dielectric ceramic composition has excellent microwave dielectric properties, it is possible to realize a MIC wiring board with excellent performance. be.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing an example of the cross-sectional structure of a wiring board according to the present invention. 2: Dielectric 4: Internal conductor path 6: Surface conductor path 8: Earth conductor path 1o:m anti-Wi1 diagram

Claims (7)

[Claims] (1) A dielectric ceramic composition obtained by firing a mixed powder of cordierite-based glass and TiO_2, in which the TiO_2 particles are dispersed in the cordierite crystalline matrix produced, and the glass and TiO_2 are used in a ratio that satisfies the following formula: 70≦χ<100 0<y≦30 χ+y=100 (where χ: weight % of glass y: weight % of TiO_2) dielectric ceramic composition. (2) A filler powder having a dielectric constant of 30 or less is further added to 100 parts by weight of the mixed powder in a total amount not exceeding 30 parts by weight. 1) The dielectric ceramic composition described above. (3) The ratio of cordierite-based composition glass and TiO_2 that satisfies the following formula: 70≦χ<100 0<y≦30 χ+y=100 (where χ: weight% of glass y: weight% of TiO_2) Using a mixed powder obtained by uniformly blending the mixed powder, a molded body formed from this mixed powder was
1. A method for producing a dielectric ceramic composition, which comprises firing at a temperature of 00° C. or lower to densify the glass and crystallize the glass to produce a cordierite crystalline phase. (4) A filler powder having a dielectric constant of 30 or less is further blended in a proportion not exceeding 30 parts by weight in total with respect to 100 parts by weight of the mixed powder (
3) Method for producing the dielectric ceramic composition described above. (5) In a wiring board having a dielectric and at least one conductor path provided in the dielectric, the dielectric is
The proportion of glass with cordierite composition is χwt%, Ti
When the proportion of O_2 is y% by weight, these two components are
The following formula: 50≦χ<100 0<y≦30 χ+y=100 Formed by firing a mixed powder that satisfies the following, and in the cordierite crystalline matrix produced. A wiring board characterized in that it is made of porcelain in which the TiO_2 particles are dispersed. (6) A filler powder having a dielectric constant of 30 or less is further blended in a proportion not exceeding 30 parts by weight in total with respect to 100 parts by weight of the mixed powder (
5) The wiring board described. (7) Claim (5) or (7) wherein the conductor path is formed of an Ag-based conductor, a Cu-based conductor, or an Au-based conductor.
6) The wiring board described.