JP4688013B2 - Low-frequency firing dielectric material for high frequency and multilayer electronic component for high frequency - Google Patents

Description

【００１１】
また比較例として、ＺｒＯ_２量が０．０１重量％満たない試料、および２重量％超える試料について、前記実施例と同様に作製し、評価を行った結果を表１に示す。
ＺｒＯ_２が０．０１重量％に満たないものは、ｆＱは大きな値を示すが、抗折強度が２２０ＭＰａ以下と低下した。また、ＺｒＯ_２が２重量％を超えるものでは、高い抗折強度を示すがｆＱが５ＴＨｚ以下と低い値しか得られなかった。
【００１２】
このような誘電体材料を用いて、以下の様にグリーンシートを成形し、積層体内部に伝送線路を形成した積層部品として、４５３２サイズ（長手４．５ｍｍ×短手３．２ｍｍ×高さ１．０ｍｍ）の積層電子部品（アンテナスイッチ）を作製した。図１はその外観であり、図２はその等価回路である。
前記、仮焼粉を、エタノール中に分散させてボールミルで平均粒径１．２μｍまで粉砕し、更に、シート成形用のバインダーであるＰＶＢ（ポリビニルブチラール）を仮焼粉重量に対して１２ｗｔ％、および可塑剤であるＢＰＢＧ（ブチルフタリルブチルグリコレート）７．５ｗｔ％を添加し、同一のボールミルにて、溶解・分散を行い、シート成形用のスラリーを得た。前期スラリーを減圧下で、脱泡および一部の溶剤の蒸発を行い、約１００００ｍＰａ・ｓの粘度になるように調整した。粘度調整後、ドクターブレードにて、シート成形を行い、乾燥後約１００μｍの厚さのセラミックグリーンシートを得た。後工程のハンドリングのため、約１５０ｍｍ角の大きさに裁断した。
積層電子部品とするため、複数枚のセラミックグリーンシート表面にＡｇペーストにて伝送線路を構成する配線パターンＬ１−１，Ｌ１−２，Ｌ２−１，Ｌ２−２を形成した(図３参照)。前記セラミックグリーンシートは各層間の配線パターンを接続するため、スルーホールもレーザー穴あけ装置により、必要に応じて形成した。前記印刷後のセラミックグリーンシートを、所定のパターンの画像処理による位置合わせを行って積層圧着した。圧着条件は、圧力１４ＭＰａ、温度８５℃、１０分保持で行った。
前記セラミック積層体を焼成後４５３２サイズになるようにチップサイズに切断した後、焼成セッターに配置し、連続炉で脱バインダー及び焼成を行った。焼成は大気雰囲気中９００℃で２時間保持した。
焼成後、内部配線が露出している部分に、Ａｇを主成分とし、ガラス成分を含む外部電極ペーストを塗布し、８００℃で焼き付け後、電解めっきにて、焼き付け後の銀表面に、ニッケルめっきおよびスズめっきを行い端子電極ＧＮＤ，ＴＸ，ＲＸ，ＶＣ１，ＶＣ２として積層基板２とした。これにダイオードＤ１，Ｄ２を実装して積層電子部品１を作製した。この積層電子部品は、図２に示した等価回路の破線部を構成するものであり、ＡＮＴ−ＲＸ間、ＴＸ−ＶＣ１間が直流的に接続している。
【００１３】
このようにして得られた積層電子部品をプリント基板に半田つけし、このプリント基板を、携帯電話と同等の重量にした枠状のアルミニウム製の治具にねじ止めして、固定した後、２ｍのコンクリート面に落下させて、電気的な断線をテスターで調べ、また外観のクラック、割れを２０倍の実体顕微鏡で調べた。
本発明に係る実施例の積層電子部品の端子間の導通は、全て断線無く、また抵抗値の変化も試験前後でレンジ５％以下であった。更に、クラック、割れなどは観察されなかった。一方、比較例Ｎｏ．１〜３のものでは、伝送線路が断線したり、割れやクラックが発生した。
【００１４】
【発明の効果】
前記実施例に示したように、本発明によれば、ｆＱが高く、機械的強度が大きい高周波用低温焼成材料を提供することができる。また、機械的強度が大きいことから、携帯電話機の信頼性試験の一つである、落下試験への耐久性が高く、信頼性の高い高周波用積層電子部品を提供することが可能となる。
【図面の簡単な説明】
【図１】 本発明の一実施例に係る積層電子部品の斜視図。
【図２】 本発明の一実施例に係る積層電子部品の等価回路。
【図３】 本発明の一実施例に係る積層基板の分解斜視図。
【符号の説明】
１ 積層電子部品
２ 積層基板
Ｌ１、Ｌ２ 伝送線路
Ｌ１−１、Ｌ１−２、Ｌ２−１、Ｌ２−２ 配線パターン
ＧＮＤ、ＴＸ，ＲＸ，ＶＣ１，ＶＣ２ 端子電極[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a high-frequency low-temperature fired dielectric material mainly used for electronic parts for mobile phones, and also relates to a high-frequency laminated electronic part using this material.
[0002]
[Prior art]
With the growing needs for miniaturization, high functionality, and weight reduction of mobile phones, the electronic components used in mobile phones have been reduced in size by combining multiple functions as a single component from a conventional single-function component having one function. It has changed to what was configured.
As a means to make electronic components smaller and more complex, LTCC materials are used to incorporate a large number of circuit elements such as inductors and capacitors in a multilayer substrate, and high-frequency circuits such as matching circuits, filters, directional couplers, and phase lines can be used. It is configured to combine an amplifier, a switch and the like by configuring and further mounting a semiconductor element or the like. As such a dielectric material for electronic parts, a material with low loss at high frequency, that is, a material having a high fQ, and can be simultaneously fired with Ag or Cu having high electrical conductivity for a wiring material inside the part. Therefore, many materials have been proposed (for example, Patent Document 1).
[0003]
[Patent Document 1]
JP 2000-272960 A
[0004]
Incidentally, there is a drop test as one of the reliability tests of the mobile phone. This test is a test in which a mobile phone is dropped from a height of 1.5 to 2 m onto a concrete surface to check whether there is any electrical functional deterioration. Since the thickness of the printed circuit board and the housing on which the electronic component is mounted has been reduced due to the weight reduction of the mobile phone, not only the function of the electronic component but also the mechanical strength and impact resistance of the component itself are large. And after soldering a component to a printed circuit board, there is an increasing demand for greater adhesion strength of the terminals.
[0005]
[Problems to be solved by the invention]
A multilayer electronic component was fabricated using a conventional low-frequency fired dielectric material for high-frequency, and the mechanical strength and impact resistance were evaluated by simulating the drop test, which is the reliability test of the mobile phone described above. Occurred, and some of the electrical functions could not be maintained, and some were destroyed.
In order to improve the strength, there is a method by changing the wiring structure inside the electronic component, but there is a limit. For this reason, it is necessary to improve the strength by examining the composition of the dielectric material itself. However, in the conventional low-temperature fired dielectric material, it is not possible to improve the strength while maintaining a high fQ of the material. There was a problem that it was difficult.
Accordingly, an object of the present invention is to provide a high-frequency low-temperature fired dielectric material having high fQ and high mechanical strength in a high-frequency low-temperature fired dielectric material, and thus providing a multilayer electronic component having high mechanical strength. It is.
[0006]
[Means for Solving the Problems]
In the first invention, the main component is composed of oxides of Al, Si, Sr, and Ti, and Al, Si, Sr, and Ti are converted into Al ₂ O ₃ , SiO ₂ , SrO, and TiO ₂ , respectively, for a total of 100 masses. % In terms of Al ₂ O ₃ , 10 to 60% by mass, 25 to 60% by mass in terms of SiO ₂ , 7.5 to 50% by mass in terms of SrO, 20% by mass or less in terms of TiO ₂ (0% (Including Al), Si, Sr, and Ti, and at least one of the group of Bi, Na, K, and Co as an accessory component with respect to the total of 100% by mass is 0.1 in terms of Bi ₂ O _3. -10% by mass, 0.1 to 5% by mass in terms of Na ₂ O, 0.1 to 5% by mass in terms of K ₂ O, 0.1 to 5% by mass in terms of CoO, and further in terms of ZrO ₂ It contains 0.01-2% by mass of Zr, and in the structure, SrAl ₂ Si ₂ O ₈ More than the hexagonal feldspar group crystal containing SrAl ₂ Si ₂ O ₈ as the main component, the bending strength is 250 MPa or more, and the fQ is 8 THz or more. It is a low-temperature fired dielectric material for high frequency, characterized in that it is fired simultaneously with Ag and Cu.
Further, as a sub-component with respect to 100% by mass of the main component, at least one of the group of Cu, Mn, and Ag is 0.01 to 5% by mass in terms of CuO and 0.01 to 5% in terms of MnO _2. %, preferably it has 0.01 to 5 mass% containing the Ag.
In the first or second invention, if ZrO ₂ is less than 0.01% by weight, the effect of improving the mechanical strength is insufficient. On the other hand, if it exceeds 2% by weight, a decrease in fQ is observed, which is preferable. Absent. In order to further expect the effect of improving the mechanical strength due to the addition of ZrO ₂ , 0.3 wt% to 1.5 wt% is more preferable.
In the first or second invention, the structure includes a ZrO ₂ crystal together with a feldspar group crystal containing SrAl ₂ Si ₂ O ₈ as a main component. In the structure, a feldspar group crystal mainly composed of hexagonal SrAl ₂ Si ₂ O ₈ and a feldspar group crystal mainly composed of monoclinic SrAl ₂ Si ₂ O ₈ are mixed, and the relative In particular, it is preferable that the feldspar group crystal mainly composed of monoclinic SrAl ₂ Si ₂ O ₈ contains more feldspar group crystal mainly composed of hexagonal SrAl ₂ Si ₂ O _8. More preferably, the feldspar group crystal mainly composed of SrAl ₂ Si ₂ O ₈ is a monoclinic feldspar group crystal.
A third invention is a high-frequency multilayer electronic component configured using the high-frequency low-temperature fired dielectric material of the first or second invention.
[0007]
(Function)
The present inventors have disclosed a dielectric material as a basis of the low-frequency fired dielectric material for high frequency in Patent Document 1. Using this dielectric material, the improvement of strength by additives was investigated, centering on various oxide ceramics. As a result, it was found that the addition of a predetermined amount of ZrO ₂ is effective in improving the mechanical strength.
The mechanism for improving the mechanical strength was examined in detail by X-ray diffractometry, focusing on the crystal system in the structure. The dielectric material which is the basis of the present invention shrinks and densifies from around 800 ° C. using the fluidity of glass, and then has SrAl ₂ Si ₂ O ₈ as a main component at a holding temperature of 900 ° C. or higher. A feldspar group crystal grows and has a structure that crystallizes from a glassy state. With this configuration, the fQ characteristics and mechanical strength can be improved. The SrAl ₂ Si ₂ O ₈ crystal system starts to partially crystallize even at around 850 ° C. and is hexagonal in that temperature range, but after being held at 900 ° C. or higher, it is monoclinic. Change to crystal system (b-axis).
The lattice constants of hexagonal crystals of SrAl ₂ Si ₂ O ₈ are a: 0.520 nm, b: 0.520 nm, and c: 0.760 nm, respectively (see JCPDS file, card No. 35-0073). On the other hand, the lattice constants of monoclinic crystals are a: 0.839 nm, b: 1.297 nm, and c: 0.713 nm, respectively (see JCPDS file, card No. 38-1454).
ZrO ₂ is orthorhombic and the lattice constants are a: 0.504 nm, b: 0.509 nm, and c: 0.526 nm, respectively (see JCPDS file, card No. 37-1413). .
Hexagonal SrAl ₂ Si ₂ O ₈ and ZrO ₂ appearing in the initial stage of crystallization have crystal structures different from those of hexagonal and orthorhombic, and the c-axis of lattice constant values is different. And the values on the b-axis are very close. For this reason, the presence of orthorhombic ZrO ₂ promotes crystallization of hexagonal SrAl ₂ Si ₂ O ₈ , and further, the change to the monoclinic system (b-axis) is accelerated, resulting in sufficient crystallization. Thought that would go. While the verification of the crystallization level, the sintered body of dielectric material with addition of ZrO ₂ calcined at 900 ° C. and observed by TEM (transmission electron microscope), the glass phase in the tissue by analyzing electron beam diffraction image When the presence or absence of this was investigated, its presence could not be confirmed, and all confirmed phases were practically crystalline phases.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, examples will be described in detail.
As starting materials for low-frequency fired dielectric materials for high frequencies, Al ₂ O ₃ , SiO ₂ , SrCO ₃ , TiO ₂ , Bi ₂ O ₃ , Na ₂ CO ₃ , K ₂ CO ₃ , CoO, CuO, MnO ₂ , Ag, The raw material powder of ZrO ₂ was weighed so as to have the composition shown in Table 1 after calcination, and mixed with pure water by a ball mill to obtain a mixed slurry. After adding 1 wt% of PVA to the slurry with respect to the weight of the slurry, the slurry was dried with a spray dryer to obtain a granular dry powder having an average particle size of about 0.1 mm.
The granulated powder was calcined at a maximum temperature of 800 ° C. in a continuous furnace to obtain a calcined powder having a target composition. Table 1 also shows comparative examples that are outside the scope of the present invention. In this comparative example, parentheses are added to the sample number to distinguish it from the examples.
First, using this calcined powder, a measurement sample was prepared by the following procedure for the measurement of fQ.
The calcined powder was put into a ball mill having an internal volume of 4 L together with pure water and pulverized to an average particle size of 1.2 μm. The pulverized slurry was evaporated with a dryer and pulverized with a lycra machine. A 10% aqueous solution of PVA (polyvinyl alcohol) was added to this powder in an amount of 10 to 20% by weight based on the weight of the powder. After kneading, it was made into granulated powder through a 32 mesh sieve. This granulated powder was put into a mold capable of obtaining a cylindrical molded body, and pressure-molded at a pressure of 200 MPa to obtain a cylindrical molded body. The molded body was fired in the atmosphere at 900 ° C. for 2 hours to obtain a fired body. Using this fired body, fQ was obtained from the resonance frequency f and Q value by the dielectric resonator method. The results are shown in Table 1. All Example Nos. 4-10, no. In 14-27, fQ showed the high value of 8 THz or more.
[0009]
Next, in order to evaluate the mechanical strength, a test piece of 38 mm × 12 mm × 1 mm was prepared by the same process as described above, and the distance between fulcrums was set to 30 mm by a bending strength test method defined as JIS C2141. A three-point bending test was performed at a speed of 0.5 mm / min, and the bending strength (bending strength) was determined from the maximum load when the test piece broke. The results are shown in Table 1. All Example Nos. 4-10, no. In 14-27, the bending strength showed a high value of 250 MPa or more.
[0010]
[Table 1]

[0011]
In addition, as a comparative example, Table 1 shows the results of producing and evaluating a sample in which the amount of ZrO ₂ is less than 0.01% by weight and a sample exceeding 2% by weight in the same manner as in the above example.
When ZrO ₂ was less than 0.01% by weight, fQ showed a large value, but the bending strength decreased to 220 MPa or less. In addition, when ZrO ₂ exceeds 2% by weight, high bending strength was exhibited, but fQ was only 5 THz or less, and a low value was obtained.
[0012]
Using such a dielectric material, a green sheet is molded as follows, and a transmission part is formed inside the laminate, so that it is a 4532 size (long length 4.5 mm × short side 3.2 mm × height 1). 0.0 mm) laminated electronic component (antenna switch). FIG. 1 shows its appearance, and FIG. 2 shows its equivalent circuit.
The calcined powder is dispersed in ethanol and pulverized with a ball mill to an average particle size of 1.2 μm. Further, PVB (polyvinyl butyral) as a binder for forming a sheet is 12 wt% based on the weight of the calcined powder, Then, 7.5 wt% of BPBG (butyl phthalyl butyl glycolate) as a plasticizer was added, and dissolution and dispersion were performed in the same ball mill to obtain a sheet forming slurry. The slurry was adjusted to a viscosity of about 10,000 mPa · s by degassing and evaporating a part of the solvent under reduced pressure. After adjusting the viscosity, a sheet was formed with a doctor blade, and after drying, a ceramic green sheet having a thickness of about 100 μm was obtained. For handling in the subsequent process, it was cut into a size of about 150 mm square.
In order to obtain a laminated electronic component, wiring patterns L1-1, L1-2, L2-1, and L2-2 constituting the transmission line were formed with Ag paste on the surface of a plurality of ceramic green sheets (see FIG. 3). Since the ceramic green sheets connect the wiring patterns between the layers, through holes were also formed as necessary by a laser drilling device. The printed ceramic green sheet was subjected to alignment by image processing of a predetermined pattern and laminated and pressure-bonded. The pressure bonding conditions were a pressure of 14 MPa, a temperature of 85 ° C., and a 10 minute holding.
The ceramic laminate was cut into a chip size so as to have a size of 4532 after firing, and then placed on a firing setter, and the binder was removed and fired in a continuous furnace. Firing was held at 900 ° C. for 2 hours in an air atmosphere.
After firing, an external electrode paste containing Ag as a main component and glass component is applied to the exposed internal wiring, and after baking at 800 ° C., electrolytic plating is performed on the silver surface after baking. Then, tin plating was performed to obtain a laminated substrate 2 as terminal electrodes GND, TX, RX, VC1, and VC2. The diodes D1 and D2 were mounted on this, and the laminated electronic component 1 was produced. This multilayer electronic component constitutes the broken line portion of the equivalent circuit shown in FIG. 2, and the ANT-RX and TX-VC1 are connected in a direct current manner.
[0013]
The multilayer electronic component obtained in this way is soldered to a printed circuit board, and this printed circuit board is screwed and fixed to a frame-shaped aluminum jig having a weight equivalent to that of a mobile phone. The test piece was dropped on the concrete surface, and the electrical disconnection was examined with a tester, and the appearance cracks and cracks were examined with a 20 × stereo microscope.
The conduction between the terminals of the laminated electronic component of the example according to the present invention was not disconnected, and the change in resistance value was 5% or less before and after the test. Furthermore, no cracks or cracks were observed. On the other hand, Comparative Example No. In the cases of 1 to 3, the transmission line was disconnected, or cracks and cracks occurred.
[0014]
【The invention's effect】
As shown in the above embodiments, according to the present invention, it is possible to provide a low-frequency fired material for high frequency with high fQ and high mechanical strength. In addition, since the mechanical strength is high, it is possible to provide a highly reliable multilayer electronic component for high frequency that has high durability against a drop test, which is one of the reliability tests of mobile phones.
[Brief description of the drawings]
FIG. 1 is a perspective view of a multilayer electronic component according to an embodiment of the present invention.
FIG. 2 is an equivalent circuit of a multilayer electronic component according to an embodiment of the present invention.
FIG. 3 is an exploded perspective view of a multilayer substrate according to an embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Laminated electronic component 2 Laminated board L1, L2 Transmission line L1-1, L1-2, L2-1, L2-2 Wiring pattern GND, TX, RX, VC1, VC2 Terminal electrode

Claims (4)

When the main component is composed of oxides of Al, Si, Sr, and Ti, and Al, Si, Sr, and Ti are converted to Al ₂ O ₃ , SiO ₂ , SrO, and TiO ₂ , respectively, and the total amount is 100% by mass, then Al 10-60 mass% in terms of ₂ O ₃ , 25-60 mass% in terms of SiO ₂ , 7.5-50 mass% in terms of SrO, 20 mass% or less (including 0%) in terms of TiO ₂ , Si, , Sr, Ti,
As a subcomponent, at least one of the group of Bi, Na, K and Co is 0.1 to 10% by mass in terms of Bi ₂ O ₃ and 0.1 to 0.1% in terms of Na ₂ O with respect to the total of 100% by mass. 5% by mass, 0.1 to 5% by mass in terms of K ₂ O, 0.1 to 5% by mass in terms of CoO, and 0.01 to ₂ % by mass in terms of ZrO ₂
In _tissue, rich in feldspar group crystal to a monoclinic composed mainly of SrAl ₂ Si ₂ O ₈ than feldspar group hexagonal crystal system composed mainly of SrAl 2 _Si 2 _{O 8,}
The bending strength is 250 MPa or more, and has an fQ value of 8 THz or more,
A low-temperature fired dielectric material for high frequency, which is fired simultaneously with Ag and Cu. With respect to the main component, further, Cu, Mn, at least one selected from the group of Ag, 0.01 to 5 mass% in terms of CuO, 0.01 to 5 mass% with MnO ₂ in terms of the Ag 0 The low-temperature fired dielectric material for high frequencies according to claim 1, wherein the dielectric material is contained in an amount of .01 to 5% by mass . The low-temperature fired dielectric material for high frequency according to claim 1 or 2, wherein the structure contains ZrO ₂ crystal together with feldspar group crystal mainly composed of SrAl ₂ Si ₂ O ₈ .   A multilayer electronic component for high frequency, wherein the low-temperature fired dielectric material for high frequency according to any one of claims 1 to 3 is used.

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