JP3904919B2 - Method for manufacturing ceramic substrate and ceramic substrate - Google Patents

Description

【００４２】
【表２】

【００４３】
【表３】

【００４４】
この表１〜３から、高軟化点ガラスを全く添加しない試料Ｎｏ．１、３、５、１６、２４では、気孔率が５％以上存在した主組成物に対して、高軟化点ガラスを添加することによって気孔率４％以下に低減することができた。その結果、磁器の強度も２７０ＭＰａ以上に大幅に向上するとともに、誘電損失も低減することができＱ値が３０００以上の磁器を得ることができた。また、この表１の組成物によれば、熱膨張係数が８×１０^-6／℃以上であり、プリント基板との良好な実装が可能となるものである。
【００４５】
【発明の効果】
以上の通り、本発明によれば、９００〜１１００℃程度の比較的低温でＡｇ系やＣｕ系、Ａｕ系等の導体金属と同時焼成でき、プリント基板との熱膨張係数と近似した熱膨張係数を持ち、かつ高い強度を有するセラミック基板が得られ、有機樹脂を含むプリント基板に実装する上で高い実装信頼性を持ち、また、高い耐衝撃性を持つ回路基板が実現できる。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for manufacturing a ceramic substrate applied to a multilayer circuit board and the like, and a ceramic substrate. In particular, the present invention can be co-fired with Ag and Cu, and has high mounting reliability for a printed circuit board made of an organic resin. the Have, a manufacturing method and a ceramic substrate of lifting Tsuse ceramic substrate with high impact resistance.
[0002]
[Prior art]
Conventionally, a ceramic wiring board is configured by forming a wiring conductor made of a refractory metal such as W or Mo between ceramic layers such as alumina, and as a wiring board on which a semiconductor element such as LSI is mounted on the surface thereof. Has been used.
[0003]
In recent years, along with the development and popularization of mobile communications such as mobile phones, miniaturization, high functionality, low price, low power, etc. of communication devices and electronic devices have been promoted, Au, Ag, Cu Ceramic wiring boards in which resonators, capacitors, coils, filters, and the like are formed of low melting point, low resistance conductive materials such as Pd and Pt and low-temperature fired ceramics such as glass ceramics have been used.
[0004]
Conventionally, for example, a dielectric ceramic composition disclosed in Japanese Patent Laid-Open No. 4-292460 is made of anorthite-calcium titanate glass and TiO ₂ , and can be fired at a low temperature. It could be fired simultaneously with the conductor material.
[0005]
In addition, when mounting a multilayer wiring board on a printed circuit board containing an organic resin such as a mother board, the viewpoint of preventing the mounting part from peeling or cracking due to the stress generated by the difference in thermal expansion with the printed circuit board Therefore, it is desired that the thermal expansion coefficient of the multilayer wiring board is close to that of the printed board, or that the multilayer wiring board itself has high strength.
[0006]
[Problems to be solved by the invention]
However, although the above conventional glass ceramics can be co-fired with a conductor material such as Ag or Cu, the thermal expansion coefficient is as low as 5 to 7 ppm / ° C., and it is mounted on a printed circuit board (thermal expansion coefficient 12 to 15 ppm / ° C.). In addition, the mounting reliability was low.
[0007]
Further, the strength of the conventional glass ceramics is at most about 200 MPa, so that the above mounting reliability cannot be satisfied, and since the mechanical strength is low, there is a problem that a crack is generated due to a drop impact or the like.
[0008]
The present invention has been devised in view of such circumstances, and can be simultaneously fired with a conductive metal such as Ag, Cu, or Au at a relatively low temperature of about 900 to 1100 ° C. and has high strength. it is an object to provide a manufacturing method and a ceramic substrate of Rousset ceramic substrate.
[0009]
[Means for Solving the Problems]
The method for producing a ceramic substrate of the present invention comprises a step of preparing a slurry by mixing a main ceramic composition, a composition for a ceramic substrate comprising 2 to 15% by mass of glass , an organic binder and a solvent, and the slurry. a step of forming into a sheet, and a through hole is formed as desired on the sheet, a step of filling the metal paste in the through holes, and forming a circuit pattern in the metal paste on the sheet surface by the scan screen printing, the a step of stacking a plurality of sheets on the basis of the circuit pattern to produce a laminate, is contracted to 80% of the final amount of shrinkage by firing the laminate at a temperature below the softening point of the glass, formed by and a step of densification to the softening point or higher temperatures to soften the glass porosity of the glass is more than 4% And wherein the door.
[0010]
Moreover, it is desirable to use glass containing at least SiO ₂ —Al ₂ O ₃ —alkaline earth oxide as the glass.
[0011]
Moreover, it is desirable to use the main ceramic composition comprising 80% by mass or more of filler and 20% by mass or less of glass. Moreover, it is desirable to use the main ceramic composition composed of a filler of less than 80% by mass and a glass of more than 20% by mass.
[0012]
When representing the composition formula by molar ratio _{(1-X) MgTiO 3 ·} XCaTiO 3, a component wherein X satisfies 0 ≦ X ≦ 0.2, with respect to the component 100 parts by mass, the B _{B 2 3} to 20 parts by mass in terms of O ₃ , 1 to 10 parts by mass in terms of carbonate of alkali metal , 0.01 to 5 parts by mass of Si in terms of SiO ₂ , 0.1 to 5 parts of alkaline earth metal in terms of oxide It is desirable to use the main ceramic composition containing 5 parts by mass.
[0013]
The ceramic substrate of the present invention is manufactured by the method for manufacturing a ceramic substrate described above, and includes at least one crystal phase having a material Q value at 2 GHz of 3000 or more.
[0014]
Further, the ceramic substrate of the present invention, selected from the group of at least _{MgTiO 3, CaTiO 3, Mg 2} SiO 4, Mg 3 TiB 2 O 6, Li 2 TiSiO 6, Al 2 O 3, ZrO 2, CaZrO 3, MgSiO 3 It is desirable to include at least one crystalline phase.
[0015]
Moreover, as for the ceramic substrate of this invention, it is desirable for the thermal expansion coefficient between 40-400 degreeC to be 8 * 10 < ^-6 > / degreeC or more.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Manufacturing method and a ceramic substrate composition are use in the ceramic substrate of the ceramic substrate of the present invention, with respect to porosity shrinkage capable main ceramic composition until 10% or less in the firing process, the main ceramic composition It is formed by adding 2 to 15% by mass of glass that softens after progressing 80% of the final shrinkage alone.
[0017]
Here, with respect to the main ceramic composition capable of shrinking until the porosity becomes 10% or less in the firing process, the main ceramic composition alone softens after progressing 80% of the final shrinkage (hereinafter, Is added to the voids remaining in the main ceramic composition, and then the high softening point glass softens and flows into the voids remaining in the main ceramic composition. It is possible to reduce the porosity to be 5% or less, which remains in the aggregate and becomes a fracture source that lowers the mechanical strength.
[0018]
Further, the amount of addition of this glass is set to 2 to 15% by mass. If it is less than 2% by mass, the porosity is more than 5% because it is insufficient to fill the voids. This is because it becomes easy to make and the porosity exceeds 5%, and in all cases, the three-point bending strength cannot be achieved more than 250 MPa.
[0019]
The main ceramic composition is composed of a mixture of glass and filler, the composition of which is composed of 20% by mass or less of glass and 80% by mass or more of filler a, or less than 80% by mass of filler, and 20 Any of the compositions b composed of glass exceeding mass% can be used.
Main composition a
The composition example of the main ceramic composition a, composition formula by molar ratio _{(1-X) MgTiO 3 ·} XCaTiO 3
When X represents 0 ≦ X ≦ 0.2 and 100 parts by mass of the component, B is ₃ to 20 parts by mass in terms of B ₂ O ₃ and the alkali metal is alkali metal carbonate. 1 to 10 mass parts with salt terms, 0.01 to 5 parts by mass of Si in terms of SiO _2, further major ceramic composition containing 0.1 to 5 parts by weight of alkaline earth metal in the alkaline earth metal oxide equivalent Is mentioned. A ceramic having a porosity of 5% or less is obtained by firing a ceramic composition obtained by adding 2 to 15% by mass of a glass that softens after the main ceramic composition progresses 80% of the final shrinkage alone. can get.
[0020]
Here, X is set to 0 ≦ X ≦ 0.2. When X exceeds 0.2, the temperature coefficient of the resonance frequency becomes too large on the plus side (exceeds 40 × 10 ⁻⁶ / ° C.). Because. In particular, 0.01 ≦ X ≦ 0.17 is desirable. Further, in the MgTiO ₃ and CaTiO _3, Mg / Ti ratio or Ca / Ti ratio be in the range of 0.9 to 1.1, it can be used in the ceramic substrate of the present invention.
[0021]
Also, the reason why B is 3 to 20 parts by mass in terms of B ₂ O ₃ is that when B is less than 3 parts by mass, it does not sinter even at 1100 ° C. and is co-fired with a conductor mainly composed of Ag or Cu. This is because when the amount exceeds 20 parts by mass, the grain boundary phase having a low Q value increases and the Q value decreases. Examples of the B-containing compound include metal boron, B ₂ O ₃ , collimite, CaB ₂ O ₄ , and glass containing boron.
[0022]
In addition, the alkali metal was converted to 1 to 10 parts by mass in terms of alkali metal carbonate, and when it is less than 1 part by mass, it is not sintered even at 1100 ° C. This is because the Q value is lowered when it is not possible and exceeds 10 parts by mass. Examples of the alkali metal include Li, Na, and K. Among these, Li is particularly desirable. Examples of the alkali metal-containing compound include carbonates and oxides of the above alkali metals.
[0023]
Furthermore, the reason why Si is set to 0.01 to 5 parts by mass in terms of SiO ₂ is that when it is less than 0.01 parts by mass, the shrinkage start temperature becomes high and co-firing with Ag and Cu becomes difficult. On the other hand, if it exceeds 5 parts by mass, the relative dielectric constant εr or the Q value decreases.
[0024]
In addition, when the alkaline earth metal was converted to alkaline earth metal oxide in an amount of 0.1 to 5 parts by mass, the shrinkage start temperature was higher than 830 ° C. when the amount was less than 0.1 parts by mass, and the effect of addition was high. I can't get it. This is because if it exceeds 5 parts by mass, the temperature coefficient of the resonance frequency becomes too large on the plus side. Examples of the alkaline earth metal include Mg, Ca, Sr, and Ba, and Ba is preferable among them. Examples of the alkaline earth metal-containing compound include carbonates and oxides of the above alkaline earth metals.
Main composition b
In the main ceramic composition b, a known glass is used as the glass. For example, SiO ₂ -Al ₂ O ₃ - alkaline earth metal oxide, borosilicate glass, such as borosilicate zinc glass,
Etc. The softening point of this glass is desirably 450 to 800 ° C. When the softening point is lower than 450 ° C., defective binder removal occurs. When the softening point is higher than 800 ° C., baking at 800 to 1000 ° C. becomes difficult.
[0025]
The filler is selected from the group consisting of SiO ₂ (quartz, cristobalite, tridymite), Al ₂ O ₃ , mullite, cordierite, spinel, Mg ₂ SiO ₄ , forsterite, zirconia diopsite, enstatite, and anorthite. At least one selected is selected.
(High softening point glass)
In addition, the glass that softens in the latter stage of the sintering does not react with the main ceramic composition and needs to soften and flow into the voids of the main ceramic composition, and according to the sintering behavior of the main composition, It is necessary to select a glass having a predetermined softening point. For example, when the main ceramic composition is the composition a, a glass having a softening point of 850 ° C. or higher, particularly 870 ° C. or higher is preferably used.
[0026]
As such a glass composition, SiO ₂ —Al ₂ O ₃ —alkaline earth glass is desirable. Specifically, 30 to 55 mass% of SiO ₂ and ₂ of Al ₂ O ₃ are used. -25% by mass, alkaline earth oxides such as Mg, Ca, Ba, etc. 5-55% by mass, comprising at least one selected from the group of ZnO, B ₂ O ₃ in a proportion of 0-15% by mass It is desirable.
(Porcelain manufacturing method)
According to the present invention, 15 to 30 parts by mass of an organic binder such as methacrylic acid and 50 to 100 parts by mass of a solvent such as toluene and isopropyl alcohol are added to and mixed with 100 parts by mass of the ceramic substrate composition. A slurry is prepared, and the slurry is formed into a sheet by a method such as a doctor blade method.
[0027]
Thereafter, a through hole is formed in the sheet-like molded body by a micro drill or a laser, and a metal paste containing a metal powder such as Ag or Cu is filled in the through hole, and / or by screen printing. A circuit pattern is printed on the surface of the sheet using the metal paste . And after laminating and pressure-bonding those sheet-like molded bodies, the laminate can be fired at a temperature of 800 to 1000 ° C. to produce a ceramic substrate.
[0028]
In firing, according to the present invention, the main ceramic composition undergoes firing shrinkage as the firing temperature rises. In this process, the firing shrinkage is advanced by 80% or more of the total shrinkage. At the stage of progressing about 80%, the pores in the molded body gradually disappear, but there are about 10% closed pores or open pores and closed pores by volume, but the disappearance of the pores from here is very slow. Finally, pores are likely to remain in the porcelain.
[0029]
According to the present invention, the high softening point glass that does not contribute to the sintering process so far is melted and softened at this stage, and the softened glass is allowed to flow into the pores existing in the molded body, thereby effectively reducing the pores. Can disappear.
[0030]
In particular, according to the present invention, in the composition comprising 80% by mass or more of filler and 20% by mass or less of glass, the present invention is effective because pores are likely to remain.
[0031]
Furthermore, the present invention provides at least MgTiO ₃ , CaTiO ₃ , Mg ₂ SiO ₄ , Mg ₃ TiB ₂ O ₈ , Li ₂ TiSiO ₆ , Al ₂ O ₃ , ZrO in a porcelain obtained by firing such a composition. ₂ , containing at least one crystal phase selected from the group consisting of CaZrO ₃ and MgSiO ₃ is desirable from the viewpoint of high thermal expansion coefficient or high strength or high Q value.
[0032]
Moreover, it is desirable that the Q value at 2 GHz is 3000 or more and the coefficient of thermal expansion between 40 to 400 ° C. is 8 × 10 ⁻⁶ / ° C. or more due to the precipitation of these crystal phases, or the circuit It is desirable that the sheet resistance of the wiring forming the film is 6 × 10 ⁻⁶ / ° C. or less.
[0033]
Further, in order to ceramic board composition of the present invention has a high Q value, the material Q value at 2GHz by firing may be desirable to include at least one or more crystalline phases at least 3,000. Examples of the crystal phase include at least one selected from the group consisting of MgTiO ₃ , CaZrO ₃ , Mg ₂ SiO ₄ , Mg ₃ TiB ₂ O ₈ , Al ₂ O ₃ , and CaMgSi ₂ O ₆ .
[0034]
Incidentally, the ceramic board composition of the present invention, Fe as an impurity contamination and materials of inevitable impurities in the manufacturing process of mixing and grinding step or the like material, Hf, but sometimes contain Sn, and these If the amount of impurities is 1% by mass or less, there is no particular influence.
[0035]
【Example】
A main ceramic composition comprising the composition of Table 1 was prepared. In addition, Table 1 also shows the temperature at which firing shrinkage progresses by 80% in the firing shrinkage curve of this composition alone.
[0036]
Moreover, the glass which has the softening point shown in Table 2 as high softening point glass was prepared.
[0037]
The main ceramic composition was a powder having an average particle size of 0.8 to 3 μm, and the glass was a powder having an average particle size of 1 to 3 μm.
[0038]
With respect to the main ceramic composition shown in Table 1, several kinds of glasses having different softening points shown in Table 2 were added with an organic binder and toluene in the combination and blending ratio shown in Table 3, and mixed with an alumina ball mill. A slurry was prepared. Next, this slurry was used to form a sheet by a doctor blade method. The sheet was laminated and pressure-bonded, then cut and fired at 900 ° C. for 1 hour in the air.
[0039]
About the obtained porcelain, the thermal expansion curve in room temperature-400 degreeC was taken, and the average thermal expansion coefficient was computed. Further, the three-point bending strength was measured according to JIS R1601.
[0040]
The crystal phase in the porcelain was identified by X-ray diffraction. Further, the void area ratio was read from the SEM photograph of the mirror polished surface of the porcelain and indicated as the porosity. Further, the dielectric constant εr and Q value at 2 GHz were measured by the dielectric resonator method. These evaluation results are shown in Table 3.
[0041]
[Table 1]

[0042]
[Table 2]

[0043]
[Table 3]

[0044]
From Tables 1 to 3, Sample No. with no high softening point glass added. In 1, 3, 5, 16, and 24, it was possible to reduce the porosity to 4% or less by adding high softening point glass to the main composition having a porosity of 5% or more. As a result, the strength of the porcelain was greatly improved to 270 MPa or more, the dielectric loss was reduced, and a porcelain having a Q value of 3000 or more was obtained. Moreover, according to the composition of Table 1, the thermal expansion coefficient is 8 × 10 ⁻⁶ / ° C. or more, and good mounting with a printed circuit board is possible.
[0045]
【The invention's effect】
As described above, according to the present invention, the thermal expansion coefficient that can be co-fired with a conductive metal such as Ag, Cu, or Au at a relatively low temperature of about 900 to 1100 ° C. and approximates the thermal expansion coefficient with the printed circuit board. the have and obtained ceramic substrate having a high strength, has a top with a high mounting reliability of mounting on a printed circuit board containing an organic resin, also, the circuit board having a high impact resistance can be realized.

Claims (8)

A step of preparing a slurry by mixing a ceramic substrate composition comprising 2 to 15% by mass of a main ceramic composition, an organic binder and a solvent, a step of forming the slurry into a sheet, and a sheet optionally forming a through hole in a step of filling the metal paste in the through holes, and forming a circuit pattern in the metal paste on the sheet surface by the scan screen printing, a plurality of sheets forming said circuit pattern a step of preparing a laminate to laminate is shrunk to 80% of the final amount of shrinkage by firing the laminate at a temperature below the softening point of the glass, the temperature above the softening point of the glass production of a ceramic substrate, characterized in that glass is softened and becomes in and a step of densified to a porosity of 4% or less Law. As the glass, at least SiO ₂ -Al ₂ O ₃ The method for producing a ceramic substrate according to claim 1, wherein glass containing an alkaline earth oxide is used. The method for producing a ceramic substrate according to claim 1 or 2, wherein the main ceramic composition comprising 80% by mass or more of filler and 20% by mass or less of glass is used. The method for producing a ceramic substrate according to claim 1 or 2, wherein the main ceramic composition comprising less than 80% by mass filler and more than 20% by mass glass is used. The composition formula by molar ratio is expressed as (1-X) MgTiO ₃ ・ XCaTiO ₃ When X is expressed as a component satisfying 0 ≦ X ≦ 0.2 and 100 parts by mass of the component, B is expressed as B ₂ O ₃ 3 to 20 parts by mass in terms of conversion, 1 to 10 parts by mass of alkali metal in terms of carbonate, Si to SiO ₂ The main ceramic composition containing 0.01 to 5 parts by mass in terms of conversion and an alkaline earth metal in an amount of 0.1 to 5 parts by mass in terms of oxides is used. 5. A method for producing a ceramic substrate according to any one of 4 above. A ceramic substrate comprising at least one crystal phase having a material Q value at 2 GHz of 3000 or more produced by the method for producing a ceramic substrate according to claim 1. At least MgTiO ₃ , CaTiO ₃ , Mg ₂ SiO ₄ , Mg ₃ TiB ₂ O ₆ , Li ₂ TiSiO ₆ , Al ₂ O ₃ , ZrO ₂ , CaZrO ₃ MgSiO ₃ The ceramic substrate according to claim 6, comprising at least one crystal phase selected from the group consisting of: Thermal expansion coefficient between 40-400 ° C is 8x10 ^-6 The ceramic substrate according to claim 6 or 7, wherein the ceramic substrate is at least / ° C.