JPH09175853A - Low-temperature-baked ceramic composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject composition for use at high frequencies, having mechanical strengths sufficient as a multilayered circuit board, low in dielectric constant over high-frequency range, also low in dielectric loss tangent, and sinterable at temperatures of as low as 800-1000 deg.C enabling multilayer formation with gold(Au), silver(Ag) and/or copper(Cu) served as wiring metallic conductor. SOLUTION: This low-temperature-baked ceramic composition is obtained by molding a mixed powder comprising 80-99.9wt.% of glass composed of SiO2 , Al2 O3 , MgO, ZnO and B2 O3 , 0.1-20wt.% of cordierite followed by baking the mixed powder at 800-1000 deg.C in a nonoxidative atmosphere such as nitrogen or argon gas. This ceramic composition is composed of cordierite crystal phase 1, gahnite crystal phase 2, and glass phase 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a low temperature fired porcelain composition for a multi-layer circuit board, and more particularly, it is applied to a multi-layer composite circuit board on which semiconductor elements and various electronic parts are mounted. The present invention relates to a high-frequency low-temperature fired porcelain composition capable of copper wiring.

[0002]

2. Description of the Related Art In recent years, with the advent of advanced information technology, information transmission has become faster and higher in frequency, and semiconductor elements to be mounted have also become faster and more highly integrated, and higher packaging density is required. In various circuit boards made of alumina, which have been frequently used, the relative dielectric constant is 9 to 3 at 3 GHz.
Since the dielectric constant is 9.5, which is considerably large, it is said to be unsuitable for recent high frequency circuit boards and the like.

That is, in order to propagate a signal at high speed, the substrate material is required to have a lower dielectric constant.
Higher mechanical strength in order to prevent the substrate itself from being destroyed or chipped from the stress applied to the substrate in the process of connecting various electronic components and input / output terminals to the multilayer circuit substrate. Is also required.

Therefore, in order to satisfy the above requirements, for example, a glass sintered body made of a glass composition containing SiO ₂ , Al ₂ O ₃ and MgO as a main component has been proposed. Although the body has the property of having a low dielectric constant, the problem of low mechanical strength remains, and it does not completely satisfy the above requirements, and various research and development have been advanced in order to solve the problem for that. There is.

As a result, as a composition having a low dielectric constant and high strength, for example, a glass composition in which mullite and cordierite are precipitated as a main crystal phase by heat treatment has been proposed (Japanese Patent Laid-Open No. 05-298919). See the bulletin).

[0006]

However, the multilayer circuit board made of the glass composition proposed above has a dielectric constant and a dielectric loss tangent which are required especially as a circuit board for high frequencies.
In addition, there is a problem that not all properties such as mechanical strength are necessarily satisfied.

[0007]

DISCLOSURE OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and its object is to have a sufficient mechanical strength as a multilayer circuit board, a low relative dielectric constant in a high frequency region, and a dielectric loss tangent. It also has the characteristic of low
It is an object of the present invention to provide a high-frequency low-temperature fired porcelain composition that can be fired at a low temperature of 800 to 1000 ° C. and can be multilayered using u), silver (Ag), and copper (Cu) as wiring conductors.

[0008]

DISCLOSURE OF THE INVENTION As a result of earnest studies on the above-mentioned problems, the present inventor made use of the softening flow of glass to obtain 80
By firing at 0 to 1000 ° C., it is possible to use Au, Ag, and Cu as wiring conductors for multilayering and fine wiring, and by combining cordierite with a specific glass, a crystalline phase can be obtained. By precipitating the cordierite crystal phase and the garnite crystal phase, it is possible to lower the relative dielectric constant and the dielectric loss tangent. In particular, by precipitating the spinel type crystal phase, the garnite crystal phase, the strength is increased. Found that is possible.

That is, the low temperature fired porcelain composition of the present invention comprises at least SiO ₂ , Al ₂ O ₃ , MgO, ZnO and B.
A porcelain composition suitable for a high-frequency multilayer circuit board, which contains 80 to 99.9% by weight of glass containing ₂ O ₃ and 0.1 to 20% by weight of cordierite.
A sintered body obtained by firing at a low temperature of 0 to 1000 ° C. has a cordierite crystal phase and a garnite crystal phase.
It is characterized by containing a glass phase.

[0010]

According to the low temperature fired porcelain composition of the present invention, since cordierite is contained as a filler component, a cordierite crystal phase and a garnite crystal phase exhibiting a low dielectric constant and a low dielectric loss tangent are precipitated, and at the same time, glass By precipitating a cordierite crystal phase exhibiting a dielectric constant lower than that of the phase and a small dielectric loss tangent, it becomes possible to lower the dielectric constant and lower the dielectric loss tangent.

Further, SiO ₂ --Al ₂ O ₃ --MgO--Z
with nO-B ₂ O ₃ based glass cordierite blended as a filler component, by precipitating a spinel type crystal layer from the glass component, the transverse strength of the obtained sintered body is increased.

Furthermore, the low temperature fired porcelain composition of the present invention comprises 8
Since it can be fired at the same time as the internal wiring layer of Au, Ag or Cu at a low temperature of 00 to 1000 ° C., it is easy to achieve a fine wiring of a multilayer circuit board or a package for accommodating semiconductor elements equipped with these wiring conductors. it can.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION The low temperature fired porcelain composition of the present invention will be described in detail below.

According to the low temperature fired porcelain composition of the present invention, at least SiO ₂ , Al ₂ O ₃ , MgO, ZnO and B are added.
_{If the} amount of glass containing ₂ O ₃ is less than 80% by weight, or in other words the amount of cordierite is more than 20% by weight, the porcelain cannot be sufficiently densified at a temperature of 800 to 1000 ° C.

On the contrary, if the amount of the glass is more than 99.9% by weight, in other words, the amount of Zn in terms of oxide is less than 0.
When it is less than 1% by weight, the dielectric constant is higher than 5, and the dielectric loss tangent is higher than 12 × 10 ⁻⁴ .

Therefore, the content of the glass is 80-9.
It is specified to be 9.9% by weight, and more preferably 85 to 99% by weight.

Such a porcelain composition can be fired at a temperature of 800 to 1000 ° C. in a non-oxidizing atmosphere such as N ₂ or Ar, and FIG. 1 shows a schematic diagram of the structure of the obtained sintered body. .

As shown in FIG. 1, the low temperature fired porcelain composition of the present invention comprises a cordierite crystal phase 1, a garnite crystal phase 2 and a glass phase 3, and the cordierite crystal phase 1 Exists as a main crystal in the sintered body.

As described above, according to the present invention, it is possible to obtain a low relative dielectric constant and a low dielectric loss tangent by allowing the cordierite crystal phase to exist in the sintered body and the gernite crystal phase at the same time. it can.

It is also possible to precipitate a spinel type crystal phase (garnite phase) in the sintered body by adjusting the firing temperature.

Since these crystal phases exist in a form that reinforces the network of each crystal phase, a sintered body having high mechanical strength can be obtained.

Next, as a specific method for producing the low temperature fired porcelain composition of the present invention, SiO ₂ is used as a starting material.
_{-Al 2 O 3 -MgO-ZnO-} B 2 O 3 based glass 8
0-99.9% by weight, particularly preferably 85-99% by weight
And cordierite 0.1 to 2 as a filler component
0 wt%, especially cordierite is mixed in a proportion of 1 to 15 wt% in the total amount.

The cordierite, which is the filler component, serves as a nucleus to promote the crystallization of the glass component into the cordierite crystal phase, but it is important to crystallize the glass and uniformly precipitate the cordierite crystal phase. From this point of view, it is desirable that the cordierite powder is a fine powder having a particle size of 1.5 μm or less, particularly 1.0 μm or less.

Further, as a starting material, SiO ₂ --Al ₂
The O ₃ —MgO—ZnO—B ₂ O ₃ system glass is used because the spinel type crystal phase is precipitated by using this system glass, and this crystal phase exists in a form that reinforces the glass network, This is because a strong sintered body can be obtained.

Further, the glass of such a system is
The amount added in the range of 9.9% by weight is that the densification temperature of the sintered body is 100 when the glass amount is less than 80% by weight.
This is because the temperature becomes higher than 0 ° C. and the conductors of gold, silver and copper cannot be used, and when the amount of glass exceeds 99.9% by weight, the bending strength of the porcelain decreases.

On the other hand, as a more specific composition of the glass, SiO ₂ is 40 to 45% by weight and Al ₂ O ₃ is 25 to 45% by weight.
30 wt%, MgO 8-12 wt%, ZnO 6-9
Wt%, B ₂ O ₃ is desirably 8-11% by weight.

After appropriately adding a binder to the mixed powder mixed and mixed in the above proportions, the mixture is molded into a predetermined shape, and N
₂ , 800 to 100 in a non-oxidizing atmosphere such as Ar
Baking at a temperature of 0 ° C. for 0.1 to 5 hours. If the firing temperature at this time is lower than 800 ° C., the porcelain will not be sufficiently densified and
If the temperature exceeds 000 ° C, the conductors of gold, silver and copper cannot be used.

When a wiring board is produced using such a low temperature fired porcelain composition, for example, the mixed powder prepared as described above is subjected to a known tape forming method such as a doctor blade method or a rolling method. After molding a green sheet for forming an insulating layer, a powder of Au, Ag or Cu, especially C, is formed on the surface of the sheet as a metallization for a wiring layer.
Using a metal paste containing u powder, a wiring pattern is formed on the surface of the sheet by means of screen printing, gravure printing, offset printing, or the like, and in some cases a through hole is formed in the sheet to fill the hole with the above paste. . Then, after laminating and pressing a plurality of sheets, the wiring layer and the insulating layer can be simultaneously fired by firing under the above-described conditions.

[0029]

EXAMPLES Hereinafter, the low-temperature fired porcelain composition of the present invention will be described in detail. First, SiO ₂ -Al ₂ O ₃ -Mg
As O-ZnO-B ₂ O ₃ based crystalline glass, crystalline glass A: SiO ₂ 44 wt% -Al ₂ O ₃ 29 wt% -MgO11 wt% -ZnO7 wt% -B ₂ O ₃ 9 wt% crystalline Glass B: Two kinds of glass of SiO ₂ 50% by weight-Al ₂ O ₃ 25% by weight-MgO 9% by weight-ZnO 8% by weight-B ₂ O ₃ 8% by weight and cordierite having an average particle size of 1 μm or less. Mix according to the composition of Table 1.

Then, an organic binder, a plasticizer, and toluene were added to this mixture, and a green sheet having a thickness of 300 μm was prepared by the doctor blade method. After that, 5 sheets of this green sheet are laminated, and 100 at a temperature of 50 ° C.
A pressure of kg / cm ² was applied for thermocompression bonding. The obtained laminated body was debindered in a water vapor-containing / nitrogen atmosphere at a temperature of 700 ° C., and then fired in dry nitrogen under the conditions shown in Table 1 to obtain a sintered body.

The obtained sintered body was evaluated for permittivity, dielectric loss tangent, and bending strength by the following methods.

Regarding the dielectric constant and the dielectric loss tangent, a sample with a diameter of 50 mm and a thickness of 1 mm was cut out from the above-mentioned sintered body to 3.0 GHz.
The measurement was performed by the cavity resonator method using a network analyzer and a synthesized sweeper. In the measurement,
The measurement was performed by sandwiching the sample dielectric substrate between the cylindrical resonators filled with sapphire. The dielectric constant and dielectric loss tangent were calculated from the resonance characteristics of the TE011 mode of the resonator.

The bending strength is 70 m from the sintered body.
m, thickness 3 mm, width 4 mm to prepare a measurement sample, JIS
A 3-point bending test was performed according to the regulations of C-2141.

As a comparative example, forsterite and SiO ₂ were used in place of the cordierite as the filler component, and a sintered body was prepared and evaluated in the same manner as above.

Further, instead of the crystalline glass, crystalline glass C: SiO ₂ 55.2% by weight-Al ₂ O ₃ 12% by weight-B ₂ O ₃ 4.4% by weight-BaO 20% by weight-ZnO 6.7 wt% -Na ₂ O1.6 wt% -ZrO ₂ 0.1 wt% crystalline glass D: SiO ₂ 60.7 wt% -Al ₂ O ₃ 9.3 wt% -B ₂ O ₃ 5 wt% -SrO15 using two glass .4 wt% -ZnO8.6 wt% -K ₂ O1 wt%, average particle diameter as a filler was evaluated in the same manner by using a 1.0μm cordierite.

[0036]

[Table 1]

As is clear from the results of Table 1, in the present invention in which the cordierite crystal phase and the garnite crystal phase were precipitated as crystal phases, the dielectric constant was less than 5 and the dielectric loss tangent was 1 in both cases.
It shows a high value of 1 × 10 ⁻⁴ or less and strength of 25 kg / mm ² or more. Among these, those having a firing temperature of 850 to 900 ° C. have a dielectric constant of 5.4 or less and a dielectric loss tangent of 9 × 10 ^−4. The following are more excellent in dielectric properties.

On the other hand, in the case of sample No. 1 in which the amount of glass is less than 80% by weight, it cannot be densified unless the firing temperature is raised to 1400 ° C.
^It is as high as ^-4 , and if the glass amount exceeds 99.9% by weight, sufficient strength cannot be secured.

As a comparative example, sample No. 20 using forsterite as a filler has a large dielectric constant of 5.9, and sample No. 21 using SiO ₂ also has a dielectric loss tangent of 35 × 10 ⁻⁴ . It became quite high.

Further, in the sample numbers 14 to 19 of the comparative examples using the crystallized glasses C and D, BaAl ₂ Si ₂ O _{8 was used.}
And SrAl ₂ Si ₂ O ₈ are generated, and these have a dielectric constant of 7
Since it is as high as ~ 8, the permittivity of the whole porcelain is as high as 5.6 or more, and the dielectric loss tangent is also as large as 15 × 10 ^-4 or more.

[0041]

As described above in detail, since the low temperature fired porcelain composition of the present invention has a low dielectric constant and a small dielectric loss tangent, it can be optimally miniaturized in microwave circuit elements and the like, and further, it can be used as a substrate. By increasing the strength of the material, it is possible to improve the bonding of the leads applied to the input / output terminals and the reliability of the board during mounting, and since it is possible to fire at a low temperature of 800 to 1000 ° C, wiring using Au, Ag, Cu, etc. It can be formed by co-firing, and can be applied as a multilayer wiring substrate for various high frequencies or a substrate for a semiconductor element housing package.

[Brief description of the drawings]

FIG. 1 is a schematic view of the structure of the low-temperature fired porcelain composition of the present invention.

[Explanation of symbols]

 1 Cordierite crystal phase 2 Gurnite crystal phase 3 Glass phase

Claims (1)

[Claims] 1. At least silica (SiO ₂ ), alumina (Al ₂ O ₃ ), magnesia (MgO), zinc oxide (Z
nO) and a glass containing boron oxide (B ₂ O ₃ ) of 80 to
99.9% by weight and cordierite (Mg ₂ Al ₄ S
i ₅ O ₁₈ ) at a temperature of 800 to 1000 ° C. in a non-oxidizing atmosphere such as nitrogen (N ₂ ) or argon (Ar) in the form of a mixed powder containing 0.1 to 20% by weight. A low-temperature fired porcelain composition, wherein the sintered body obtained by firing contains a cordierite crystal phase, a garnite crystal phase, and a glass phase.