JP4748799B2 - Low-frequency fired porcelain composition for high frequency and its manufacturing method - Google Patents

Description

  The present invention relates to a low-frequency fired ceramic composition for high frequency having a low dielectric constant and low dielectric loss, and a method for producing a low-temperature fired ceramic.

  In recent years, with the era of advanced information technology, semiconductor devices are required to have higher speed, higher integration, and higher mounting density. To increase the speed of semiconductor devices, it is essential to increase the signal propagation speed on the circuit in addition to shortening the wiring length, but the signal propagation speed is inversely proportional to the square root of the relative dielectric constant of the substrate material. A lower dielectric constant substrate material is required. In addition, the use of low-resistivity wiring materials (Ag, Au, Cu, etc.) is required for higher integration and higher mounting density. However, these metals have a low melting point, so that after wiring pattern printing, In a multilayer wiring board or the like that fires a substrate, it is necessary to use a substrate material that can be fired at a low temperature. For this reason, the alumina substrate (dielectric constant: 9 to 9.5, firing temperature: around 1500 ° C.) that has been widely used as a substrate material for electronic equipment is not suitable for high-frequency circuit boards, and has a lower dielectric constant instead. There is a need for materials that have low temperature firing. There is also a demand for low loss in the microwave and millimeter wave bands.

  Therefore, recently, a glass ceramic material made of glass and an inorganic filler has been studied as a low dielectric constant substrate material that can cope with high speed. This kind of glass-ceramic material is suitable as a high-frequency insulating substrate because of its low dielectric constant of about 3 to 7, and since it can be fired at a temperature of 800 ° C. to 1000 ° C., Ag having a low conductor resistance. , Au, Cu and the like can be fired simultaneously.

For example, Patent Document 1 discloses that a glass phase capable of precipitating a diopside (CaMgSi ₂ O ₆ ) type crystal phase and an oxide containing Mg and / or Zn and Ti as fillers is fired at 1000 ° C. or lower. A possible high frequency porcelain composition is disclosed. Patent Document 2 discloses a crystallized glass component containing SiO ₂ , Al ₂ O ₃ , MO (M is an alkaline earth metal element) and Pb, Al ₂ O ₃ , SiO ₂ , MgTiO ₃ , (Mg, Zn) TiO ₃ , TiO ₂ , SrTiO ₃ , MgAl ₂ O ₄ , ZnAl ₂ O ₄ , cordierite, mullite, enstatite, willemite, CaAl ₂ Si ₂ O ₈ , SrAl ₂ Si ₂ O ₈ , (Sr, Ca) A high-frequency wiring board comprising at least one filler selected from the group consisting of Al ₂ Si ₂ O ₈ and forsterite is disclosed.

However, even if the conventional glass ceramic material has a low dielectric constant, the dielectric loss (tan δ) in a high frequency band of 10 GHz or more is generally as high as 20 × 10 ⁻⁴ or more, that is, the Qf value is 5 × 10 ³ to It is about 8 × 10 ³ , and does not have sufficient characteristics to be put into practical use as a high-frequency substrate material. Here, the Qf value is a product of the measurement frequency (f / GHz) and Q (≈1 / tan δ).

JP 2000-188017 A Japanese Patent Laid-Open No. 2001-240470

  Therefore, the present invention can be fired simultaneously with a low-resistance metal such as Ag, Au, Cu, etc., and can produce a low-temperature fired porcelain composition that realizes low dielectric loss and low dielectric loss in a high-frequency region, and low-temperature fired porcelain It aims to provide a method.

As a result of investigations to solve the above problems, the present inventors have found that a composition in which Bi ₂ O ₃ and Li ₂ O are added to a composite oxide containing Mg, Mn, and Si in a specific ratio is 850. It has been found that a low-temperature fired porcelain that can be fired at a temperature of about 0 to 900 ° C. and is obtained by firing such a composition has a low relative dielectric constant and a low dielectric loss, and has completed the present invention.

That is, the present invention provides the following low-temperature fired ceramic composition and method for producing a low-temperature fired ceramic.
(1) MgO, MnO, from 63 to 98.7 wt% of SiO ₂ in a total amount, including a Bi ₂ O ₃ 1.0~35% by weight and Li ₂ O0.3~2.0 wt%, the content ratio of MgO and SiO ₂ and MnO When (molar ratio) is represented by (2-x): x: y, x is in the range of 0.03 to 1.0, y is in the range of 1.2 to 10, and at least a part thereof is a composite oxidation with Mg, Mn, and Si. Low-temperature fired porcelain composition contained as a product.
(2) The composite oxide comprises a forsterite crystal phase and / or an enstatite crystal phase, a tefroid crystal phase (Mn ₂ SiO ₄ ) and / or a rhodonite crystal phase (MnSiO ₃ ), MgO—MnO—SiO _{2 2.} The low-temperature fired ceramic composition according to claim 1, wherein the composition is a crystalline phase and includes at least a part of Bi ₂ O ₃ and Li ₂ O as a Bi ₂ O ₃ —SiO ₂ crystalline phase and a Li ₂ O—SiO ₂ crystalline phase. object.
(3) The low-temperature fired ceramic composition according to claim 1 or 2, wherein the Qf value is 10,000 or more.
(4) MgO, MnO, the content ratio of SiO ₂ is, (2-x): x : is represented by y, x is 0.03 to 1.0, y is MgO in the range of 1.2 to 10, MnO, SiO _2, of Raw material powder containing mixture and / or composite oxide 63-98.7% by mass, Bi ₂ O ₃ 1.0-35% by mass and Li ₂ O 0.3-2.0% by mass is calcined (750 ° C. to 850 ° C.) and then pulverized A method for producing a low-temperature fired porcelain composition comprising forming a powder and adding a molding aid containing a binder to the powder to form a predetermined shape, followed by firing at 850 ° C. to 900 ° C.

As a result of using the oxides of Bi and Li as liquid phase forming components, the low-temperature fired ceramic composition of the present invention has a forsterite crystal phase and / or an enstatite crystal phase, a tefroid crystal phase (Mn ₂ SiO ₄ ). In addition, low temperature sinterability was realized in a porcelain composition having a rhonite-based crystal phase (MnSiO ₃ ) and an MgO—MnO—SiO ₂ crystal phase as a main phase. Further, it has been found that Bi ₂ O ₃ does not lower the dielectric loss even if it is introduced in a large amount, whereby a high Qf value can be realized. Therefore, according to the present invention, it is most suitable as a low loss LTCC (low temperature fired multilayer substrate) material having a dielectric constant (9 or less) and a high Qf (10,000 or more) that can be used in a high frequency range of 16 GHz or more. It can be used in circuit elements. And since it can bake at 850 to 900 degreeC, the wiring by Cu, Au, Ag, etc. can be formed by simultaneous baking.

(A) ceramic compositions low-temperature-sintered ceramic composition of the present invention, 63 to 98.7 wt% of MgO and MnO and SiO ₂ in a total amount, Bi ₂ O ₃ 1.0 to 35% by weight and Li ₂ O0.3~2.0 mass %, When the content ratio (molar ratio) of MgO, SiO ₂ , MnO is represented by (2-x): x: y, x is in the range of 0.03 to 1.0, y is in the range of 1.2 to 10, It is a low-temperature fired porcelain composition containing at least a part as a complex oxide of Mg, Mn, and Si.
By adding Bi ₂ O ₃ and Li ₂ O to the composite oxide containing Mg, Mn, and Si, the Bi ₂ O ₃ —SiO ₂ liquid phase and the Li ₂ O—SiO ₂ system are heated during heating. A liquid phase is formed and can be fired at a temperature of about 850 ° C. to 900 ° C. through this liquid phase reaction.

The low-temperature fired ceramic composition of the present invention comprises MgO, MnO and SiO ₂ in a total amount of 63 to 98.7% by mass, preferably 75 to 97.7% by mass, Bi ₂ O ₃ 1.0 to 35% by mass, preferably 2.0 to 24.5 wt%, Li ₂ O0.3~2.0% by weight, preferably (to 100 wt% in total) in a range of 0.3 to 0.5 wt%.
If the contents of MgO, MnO and SiO ₂ are too small, the characteristic of high Qf due to these being the main phase is impaired. Moreover, if it is excessive, low-temperature sinterability is lost. If the Bi ₂ O ₃ content is too small, low temperature sinterability cannot be realized. On the other hand, if it is excessive, the bulk density becomes 4 g / cm ³ or more, and further, 2Bi ₂ O ₃ .3SiO ₂ becomes the main phase, so the dielectric constant becomes high, which is not desirable. If the Li ₂ O content is too low, low temperature sinterability cannot be realized. If it is excessive, the dielectric loss in the high frequency region of 16 GHz is as high as 10 × 10 ⁻⁴ or more, and a high Qf value cannot be realized.

When the content ratio of MgO, MnO, and SiO ₂ is 2-x: x: y, x is in the range of 0.03 to 1.0 and y is in the range of 1.2 to 10.
The composite oxide of Mg, Mn, and Si may be any as long as the quantitative ratio of MgO, MnO, and SiO ₂ satisfies the above range.

Therefore, the low-temperature fired porcelain of the present invention comprises a forsterite crystal phase and / or an enstatite crystal phase, a tefroid crystal phase (Mn ₂ SiO ₄ ) and / or a rhodonite crystal phase (MnSiO ₃ ), MgO—MnO— It is mainly composed of a SiO ₂ crystal phase and is mainly composed of a Bi ₂ O ₃ —SiO ₂ crystal phase and a Li ₂ O—SiO ₂ crystal phase. Here, “Tefloid crystal phase” means Tefroid and similar crystal phases, “Rhodonite crystal phase” means rhodonite and similar crystal phases, and “MgO—MnO—SiO ₂ crystal phase” means MgO— It is a MnO—SiO ₂ -based crystal phase and a similar crystal phase, and may include the same type of crystal phase composed of components of the porcelain composition. The same applies to the forsterite crystal phase, the enstatite crystal phase, the Bi ₂ O ₃ —SiO ₂ crystal phase, and the Li ₂ O—SiO ₂ crystal phase.
The specific content ratio of each phase is not limited as long as the target physical property value is realized, but usually, forsterite crystal phase and / or enstatite crystal phase, tefroid crystal phase (Mn ₂ SiO ₄ ) and / or rhodonite-based crystal phase (MnSiO ₃ ), MgO—MnO—SiO ₂ -based crystal phase contains 63% or more of the total volume of the porcelain, preferably 80% or more, more preferably 90% or more, still more preferably Including 95% or more.
As long as the effects of the invention are not impaired, a SiO ₂ crystal phase or the like or an amorphous material may be included.
The low-temperature fired ceramic of the present invention has a Qf value of 10,000 or more and is densified to a relative density of 95% or more by firing in a temperature range of 850 ° C. to 900 ° C.

(B) Manufacturing method of low-temperature fired porcelain In the low-temperature fired porcelain of the present invention, the content ratio of MgO, MnO, and SiO ₂ is represented by (2-x): x: y, x is 0.03 to 1.0, and y is 1.2 to A raw material powder containing a mixture of MgO, MnO and SiO ₂ and / or composite oxide 63-98.7% by mass, Bi ₂ O ₃ 1.0-35% by mass and Li ₂ O 0.3-2.0% by mass is predetermined. It can manufacture by baking at 850 to 900 degreeC after shaping | molding in a shape.
The main raw materials Mg, Mn, and SiO ₂ may be a mixture of metal oxides, or may be a composite oxide such as enstatite (MgSiO ₃ ) mixed with required amounts of SiO ₂ , MgO, and MnO. MgO, MnO and SiO ₂ that can be used as starting materials can be added in the form of carbonates, acetates, nitrates and the like that can form oxides during the sintering process, in addition to oxide powders of the respective metals.

To the above main component material, Bi ₂ O ₃ powder, Li ₂ O powder proportion of the as a sintering aid, preferably the main component material 75 to 97.7 wt%, Bi ₂ O ₃ 2.0~24.5 weight %, Li ₂ O is added and mixed so as to be in the range of 0.3 to 0.5 mass. Bi ₂ O ₃ and Li ₂ O can also be added in the form of carbonates, acetates, nitrates, and the like that can form oxides during the sintering process, in addition to the oxide powders of the respective metals.
Raw material powders such as Mg ₂ SiO ₄ , Mn ₂ SiO ₄ , SiO ₂ , MgO, MnO, Bi ₂ O ₃ , Li ₂ O increase dispersibility, and 2.0 μm or less in order to obtain a desirable dielectric constant and low dielectric loss, In particular, it is desirable to use a fine powder of 1.0 μm or less.

After appropriately adding a binder to the mixed powder added and mixed at the above ratio, for example, after molding into an arbitrary shape by a die press, extrusion molding, doctor blade method, rolling method, etc., in an oxidizing atmosphere or N ₂ , Ar In a non-oxidizing atmosphere such as 850 ° C. to 1000 ° C., in particular at a temperature of 850 ° C. to 900 ° C. for 1 to 3 hours, it can be densified to a relative density of 95% or more. If the firing temperature at this time is lower than 850 ° C., the porcelain is not sufficiently densified, and if it exceeds 1000 ° C., densification is possible, but a low-melting conductor such as Ag, Au, or Cu is used as the wiring material. It becomes difficult.

According to the method of the present invention, a more active solid-liquid reaction between a solid phase, which is a composite oxide of Mg, Mn, and Si, and a Bi ₂ O ₃ —SiO ₂ liquid phase and a Li ₂ O—SiO ₂ liquid phase As a result, the porcelain can be densified with a small amount of sintering aid. Therefore, it is possible to minimize the amount of the amorphous phase at the grain boundary that causes the dielectric loss to increase. Thus, according to the production method of the present invention, the forsterite crystal phase and / or enstatite crystal phase, tefroid crystal phase (Mn ₂ SiO ₄ ) and / or at least Mg, Mn, and Si are contained in the porcelain. Alternatively, by depositing rhodonite crystal phase (MnSiO ₃ ), MgO—MnO—SiO ₂ crystal phase, Bi ₂ O ₃ —SiO ₂ crystal phase and Li ₂ O—SiO ₂ crystal phase, the ratio can be increased even at about 16 GHz. The dielectric constant can be controlled to 9 or less, and a high-frequency porcelain having a low dielectric loss and thus a high Qf value can be obtained.

(C) Use of Porcelain Composition Since the porcelain composition in the present invention can be baked at 850 ° C. to 900 ° C., it can be used as an insulating substrate of a wiring substrate for wiring Ag, Au, Cu and the like. In the case of producing a wiring board using such a porcelain composition, for example, the mixed powder prepared as described above can be used to form an insulating layer forming green according to a known tape molding method such as a doctor blade method, extrusion molding or the like. After producing the sheet, a screen printing method is performed on the surface of the green sheet using a conductive paste containing at least one metal of Ag, Au and Cu, in particular, Ag powder, for the wiring circuit layer on the surface of the sheet. A wiring pattern is printed in a circuit pattern by, for example, and in some cases, a through hole or a via hole is formed on a sheet, and then the conductor paste is filled. Thereafter, the plurality of green sheets are laminated and pressure-bonded, and then fired under the above-described conditions, whereby the wiring layer and the insulating layer can be fired simultaneously.

EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention concretely, these do not limit this invention.
Examples 1-29
Mg ₂ SiO ₄ , Mn ₂ SiO ₄ , MgO, SiO ₂ , MnO, Bi ₂ O ₃ , and Li ₂ CO ₃ having an average particle size of 1 μm or less are mixed so that the content ratio in terms of oxide is the ratio shown in Table 1. And calcined (750 ° C. to 850 ° C.) and then pulverized into powder. An organic binder, a plasticizer, and toluene were added to these calcined materials, and a green sheet having a thickness of 150 μm was prepared by a doctor blade method. Then, five green sheets were laminated and thermocompression bonded by applying a pressure of 150 kg / cm ² at a temperature of 70 ° C. The resulting laminate was debindered at 500 ° C. in the air and then fired in the air under the conditions shown in Table 1 to obtain a multilayer substrate porcelain. Table 1 also shows the total content of Mg, Mn and Si in the raw material mixture (oxide conversion value) and the MgO / SiO ₂ / MnO ratio.

The obtained sintered body was evaluated for dielectric constant and dielectric loss by the following methods. The measurement was performed according to JIS R1627 “Test method for dielectric constant characteristics of fine ceramics for microwaves”. That is, the above-mentioned multilayer substrate porcelain is cut into a disk shape of a sample having a diameter of 1 to 5 mm and a thickness of 2 to 3 mm, and both ends of the disk sample are short-circuited by two parallel conductor plates to form a dielectric resonator. The TE011 mode resonance characteristics and no-load Q of this dielectric resonator were measured at 16-20 GHz with a network analyzer (Hewlett Packard 8722C), and the dielectric constant and dielectric loss (tan δ) were calculated and measured. The Qf value was calculated from the frequency and Q (= 1 / tan δ). The results are shown in Table 2.
Further, X-ray diffraction measurement was performed on each sample, and the constituent phase of the porcelain was identified by comparison with the X-ray diffraction peak of the standard sample. As a result, the forsterite crystal phase (Mg ₂ SiO ₄ ) and / or the enstatite crystal phase ( MgSiO ₃ ), Tefloid crystal phase (Mn ₂ SiO ₄ ) and / or rhodonite crystal phase (MnSiO ₃ ), MgO—MnO—SiO ₂ crystal phase, Bi ₂ O ₃ —SiO ₂ crystal phase (typically Was confirmed to be present in the respective phases of eulite (2Bi ₂ O ₃ .3SiO ₄ ) and Li ₂ O—SiO ₂ based crystal phase.

As is clear from the above results, MgO, SiO ₂ , MnO, Bi ₂ O ₃ and Li ₂ O are included in the scope of the present invention, and the forsterite crystal phase and / or the enstatite crystal phase are used as the crystal phase, Tefloid crystal phase (Mn ₂ SiO ₄ ) and / or rhodonite crystal phase (MnSiO ₃ ), MgO—MnO—SiO ₂ crystal phase, Bi ₂ O ₃ —SiO ₂ crystal phase, Li ₂ O—SiO ₂ system The porcelain of the present invention in which the crystal phase is mainly precipitated exhibits excellent values such that the dielectric constant is 9 or less and the Qf value is 10,000 or more. However, when the Bi content increases, the bulk density tends to increase, and the bulk density reaches 4.09 at the upper limit of 35 mass% (Example 23) of Bi in the present invention.

Comparative Examples 1-10
Mg ₂ SiO ₄ , Mn ₂ SiO ₄ , MgO, SiO ₂ , MnO, Bi ₂ O ₃ , and Li ₂ CO ₃ with an average particle size of 1 μm or less are mixed so that the composition in terms of each oxide is the ratio shown in Table 1. In the same manner as in Examples 1 to 29, firing was performed under the conditions shown in Table 1 to obtain a ceramic for a multilayer substrate. The results are summarized in Table 2.
The sample with the Bi ₂ O ₃ content of less than 1.0% by mass (Comparative Example 2) and the sample with the Li ₂ O content of less than 0.3% by mass (Comparative Examples 3 and 4) do not sinter. When the amount of Li ₂ O exceeds 2.0 mass% and when the amount of MnO exceeds 1.0 mol, the dielectric loss is large and the Qf value is less than 10,000 (Comparative Examples 5, 6, 8, 9). In the sample (Comparative Example 7) in which the amount of Bi ₂ O ₃ is 35% by mass or more, the sample swells and causes fusion on the floor plate.

  As shown in the above examples, according to the present invention, a low-temperature fired ceramic composition for high frequency having a low dielectric constant and low dielectric loss can be obtained at a low temperature of 850 ° C. to 900 ° C.

Claims (4)

ZnO is not included, MgO, MnO and SiO ₂ are included in a total amount of 63 to 98.7% by mass, Bi ₂ O ₃ 1.0 to 35% by mass and Li ₂ O 0.3 to 2.0% by mass, and include MgO, MnO and SiO ₂ . When the content ratio (molar ratio) is represented by (2-x): x: y, x is in the range of 0.03 to 1.0, and y is in the range of 1.2 to 10, and at least a part thereof is composed of Mg, Mn, and Si. A low-temperature fired porcelain composition contained as a composite oxide. The composite oxide includes a forsterite crystal phase and / or an enstatite crystal phase, a tefroid crystal phase (Mn ₂ SiO ₄ ) and / or a rhodonite crystal phase (MnSiO ₃ ), an MgO—MnO—SiO ₂ crystal phase. The low-temperature fired ceramic composition according to claim 1, comprising at least a part of Bi ₂ O ₃ and Li ₂ O as a Bi ₂ O ₃ -SiO ₂ crystal phase and a Li ₂ O-SiO ₂ crystal phase.   The low-temperature fired ceramic composition according to claim 1 or 2, wherein the Qf value is 10,000 or more. MgO, MnO, SiO ₂ content ratio is expressed by (2-x): x: y, where x is in the range of 0.03 to 1.0 and y is in the range of 1.2 to 10 and / or a mixture of MgO, MnO, SiO ₂ and / or a composite oxide 63 to 98.7 wt%, and pulverized after calcination (750 ° C. to 850 ° C.) the raw material powder and a Bi ₂ O ₃ 1.0 to 35% by weight and Li ₂ O0.3~2.0 mass and powder, The method for producing a low-temperature fired porcelain composition according to claim 1, wherein a molding aid containing a binder is added to the resultant and then molded into a predetermined shape, followed by firing at 850 ° C to 900 ° C.