JP2004256384A - Oxide ceramic material, and ceramic substrate, laminated ceramic device, and power amplifier module using the material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an oxide ceramic material for which a complicated process or a special form is not necessary, for which a usual ceramic process only to mix/form/fire a crystalline oxide powder or a metal can be used, for which a harmful substance or an additive easy to react with a silver conductor is not necessary, in which the alumina content is high, and which can be fired at a low temperature, and to provide a ceramic substrate (1), a laminated ceramic device, and a power amplifier module using the ceramic material. <P>SOLUTION: The oxide ceramic material contains aluminum oxide as the main component and at least either A or B as an auxiliary component, A being niobium oxide and copper oxide and B being copper oxide, titanium oxide, and silver oxide. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

The present invention relates to an oxide ceramic material containing alumina (aluminum oxide, Al ₂ O ₃ ) as a main component, a multilayer ceramic substrate having a conductor inside using the same, a multilayer ceramic device, and a power amplifier module using the same. About.

  Multilayer wiring boards for mounting semiconductor ICs and the like are roughly classified into an organic substrate mainly composed of an organic material such as glass epoxy, and an inorganic substrate mainly composed of ceramic or glass such as alumina. Inorganic substrates generally have high heat resistance, high thermal conductivity, low thermal expansion, low dielectric loss, and high reliability, and are widely used.

Inorganic multilayer substrates can be broadly classified into HTCC (High Temperature Co-fired Ceramics) and LTCC (Low Temperature Co-fired Ceramics). HTCC are those used as the substrate, Al ₂ O ₃ and AlN, BeO, SiC-BeO and the like. These ceramic materials are manufactured by forming a powdery raw material and then firing at a high temperature of 1500 ° C. or higher. Therefore, Mo or W having a high melting point is used as a conductor material formed inside the multilayer substrate. Although Mo and W have the drawback of having a high resistivity as a conductor, Ag and Cu having a low resistivity have a low melting point and are melted by firing at a high temperature and cannot be used as a wiring conductor for HTCC. . Further, the firing temperature of 1500 ° C. or more is a large loss in energy.

  Accordingly, LTCC is a ceramic material such as alumina that can be sintered at a low temperature at which Ag and Cu are not melted. LTCC enables low-temperature firing by mixing a ceramic material with a low melting point glass material in a large amount of about 50 wt%. For example, lead borosilicate glass + alumina, borosilicate glass + Cordierite type and other various composition types. Since these can be fired at a temperature of about 1000 ° C. or less, Ag or Cu having low resistance can be used as the internal conductor. For this reason, LTCC is becoming mainstream at present as an inorganic multilayer substrate rather than HTCC. The LTCC material is used as a ceramic multilayer device in which a capacitor and an inductor can be easily formed therein, and has a function beyond the role of a simple wiring board. However, in an LTCC material containing a large amount of these glasses, the excellent properties inherent to alumina, such as high thermal conductivity and high mechanical strength, are lost due to the low thermal conductivity and mechanical strength of glass.

  When the thermal conductivity of the substrate is reduced, when a heat-generating element such as a power amplifier is mounted, the heat dissipation is low and the temperature rises remarkably, making it unusable. This tendency is particularly remarkable in portable devices and the like that are strongly required to be miniaturized. In order to solve this problem, a method is used in which a so-called thermal via for heat dissipation by a metal conductor is formed in a portion of the LTCC material corresponding to a lower portion of the mounted element. However, providing thermal vias reduces the degree of freedom in designing and hinders miniaturization.

Examples of the alumina-based material in which the sintering temperature is lowered without using glass include an alloy of aluminum and bismuth which is quenched and then oxidized to an amorphous state (see Patent Document 1). One in which vanadium is added simultaneously (see Patent Document 2) is disclosed.
JP-A-3-271115 JP-A-11-157921

  However, after quenching the alloy of aluminum and bismuth and then oxidizing it into an amorphous oxide, a special form of bismuth solid solution in alumina, or bismuth in alumina is essential, and other elements It takes a special form of solid solution, and its manufacturing method cannot be made by the ordinary ceramic process of simply mixing, molding and firing each raw material powder, and it is necessary to mold while applying temperature and pressure simultaneously There was a problem that mass productivity was poor. On the other hand, in the case where manganese oxide and vanadium oxide are added to alumina, these additives are harmful substances, and the amount of addition is not so small as about several percent, so that there is an environmental problem. In addition, vanadium oxide and silver Because of its high reactivity, when the internal conductor is made of silver, there is a problem that it easily reacts during firing.

  In order to solve the above-mentioned problems, the present invention uses a normal ceramic process which only requires mixing, molding and firing of crystalline oxide powder or metal without the need for complicated processes or special forms. Oxide ceramic material which has high alumina content and can be fired at low temperature without using harmful substances or additives which easily react with silver conductor, and ceramic substrate and ceramic laminated device using the same Provide power amplifier module.

The oxide ceramic material of the present invention is characterized by containing aluminum oxide as a main component and at least one selected from the following A and B as subcomponents.
A. Niobium oxide and copper oxide Copper oxide, titanium oxide, and silver oxide The ceramic substrate and the ceramic laminated device of the present invention include an insulating material made of an oxide ceramic material containing aluminum oxide as a main component and at least one of the following A and B as a subcomponent. Layers and
A. Niobium oxide and copper oxide It is characterized by having at least an inner layer of a conductor containing copper oxide, titanium oxide and silver oxide as main components.

The power amplifier module of the present invention includes an insulating layer made of an oxide ceramic material containing aluminum oxide as a main component and at least one selected from the following A and B as subcomponents:
A. Niobium oxide and copper oxide A power amplifier element is mounted on a ceramic substrate or a ceramic laminated device having at least an inner layer of a conductor mainly composed of copper oxide, titanium oxide and silver oxide.

  The present invention is a ceramic material containing aluminum oxide and a specific metal oxide. Since the ceramic material can be fired at a much lower temperature than before, the energy cost and the furnace to be used are less restricted. Further, since the content of aluminum oxide is large, it exhibits characteristics similar to the original alumina, and can be used as a substitute material for alumina.

  When this material is used for a ceramic substrate, since it can be sintered at 950 ° C. or lower, it can be configured to include a conductor containing silver having a low resistivity as a main component and used as LTCC. it can. In addition, since the thermal conductivity is high, even if a module that generates heat such as a power amplifier is mounted, a rise in temperature can be suppressed.

  Hereinafter, embodiments of the present invention will be described in detail.

  The present invention is a ceramic material characterized by its composition. The main component of the composition is alumina, and by including a plurality of specific metal oxides as sub-components, it is possible to obtain low-temperature sintering and high thermal conductivity, properties that are not present in conventional materials. Further, since the material of the present invention can be sintered at a low temperature, Ag having a low electrical resistivity can be used for the internal conductor, and LTCC having a high thermal conductivity can be obtained. Specifically, it contains at least niobium oxide and copper oxide as subcomponents.

  In the present invention, the content of the main component in the whole oxide is 80% by mass or more and 98% by mass or less, and when the remaining component is only the subcomponent, the subcomponent is 2% by mass or more and 20% by mass. % Or less, and when the composition further contains another third component in addition to the subcomponent, the total of the subcomponent and the third component is preferably 2% by mass or more and 20% by mass or less.

  When the subcomponent is A, the ratio of niobium oxide and copper oxide is preferably in the following range, when the total amount of the subcomponents is 100% by mass.

40% by mass ≦ Niobium oxide ≦ 70% by mass
30 mass% ≤ copper oxide ≤ 60 mass%
When the subcomponent is A, it is preferable to further include at least one selected from titanium oxide, silver oxide, and bismuth oxide. In particular, it is desirable that titanium oxide and silver oxide are simultaneously contained.

  Further, the ratio of niobium oxide, copper oxide, titanium oxide, silver oxide, and bismuth oxide constituting the sub-components is preferably in the following range when the total amount of the sub-components is 100% by mass.

30% by mass ≦ Niobium oxide ≦ 70% by mass
10 mass% ≤ copper oxide ≤ 60 mass%
0 mass% ≤ titanium oxide ≤ 30 mass%
0% by mass ≦ Silver oxide ≦ 30% by mass
0 mass% ≤ bismuth oxide ≤ 40 mass%
In addition, in the case of an oxide ceramic material containing aluminum oxide as a main component and at least copper oxide, titanium oxide, and silver oxide as subcomponents, the ratio of copper oxide, titanium oxide, and silver oxide constituting the subcomponent is as follows: When the total amount of the subcomponents is 100% by mass, the respective ranges are preferably in the following ranges.

10 mass% ≤ copper oxide ≤ 90 mass%
5 mass% ≤ titanium oxide ≤ 60 mass%
5% by mass ≦ Silver oxide ≦ 40% by mass
Further, the content of the aluminum oxide in the whole oxide is preferably 80% by mass or more and 98% by mass or less.

  Further, it is preferable that manganese oxide be contained in an amount of 0.1 to 2.0% by mass, based on 100 as the whole oxide.

  The oxide ceramic material is preferably sintered at a relative density of 90% or more.

  The thermal conductivity of the oxide ceramic material is preferably 5 W / mk or more, and more preferably 10 W / mk or more.

  Further, the dielectric loss at 1 MHz of the oxide ceramic material is preferably 0.05 or less, and more preferably 0.01 or less.

  The oxide ceramic material is preferably mixed with metal or metal oxide material particles, molded, and fired at a temperature of 950 ° C. or lower. Further, the oxide ceramic material may be mixed with metal or metal oxide material particles, calcined and pulverized, then molded and fired at a temperature of 950 ° C. or lower. As described above, according to the present invention, the step of forming a melt is not required at all, and the manufacturing cost can be reduced.

The material of the present invention and a method for producing LTCC using the same will be described below. The following is an example of a general manufacturing method, and the present invention is not limited to this. It is possible to make appropriate changes within a normal range of a ceramic manufacturing process. Alumina (aluminum oxide, Al ₂ O ₃ ) and various metal oxide powders are mixed well using a mixer such as a ball mill. Various kinds of balls can be used for the ball of the ball mill. However, the use of alumina balls is more preferable because the mixing amount of unnecessary impurities can be minimized. The medium at the time of mixing may be an organic solvent, but usually water may be used. Further, in order to increase the uniformity at the time of mixing and to improve the moldability, the mixed powder may be calcined and then pulverized again by a ball mill or the like.

  Note that a metal oxide may be generally used as the raw material powder. However, when firing is performed in the presence of oxygen such as in the air, part of the raw material, particularly silver oxide or copper oxide, may be made of metal silver powder or metal copper. Powder may be used.

  A small amount of a molding organic binder such as polyvinyl alcohol is mixed with the mixed powder thus obtained, and the mixture is passed through a mesh and granulated. This granulated powder is placed in a mold of an appropriate size, and molded using a pressure press to obtain a molded body.

  In addition, the same mixed powder, an organic binder for sheet molding and a solvent are sufficiently mixed and kneaded to prepare a slurry. The slurry is drawn on a base film to form a sheet, and then the sheet is dried. Green sheet. At this time, the mixing of alumina and various metal oxide powders and the mixing of the organic binder and the solvent can be performed in a single treatment.

  On the other hand, the metal powder for a conductor and an organic vehicle component composed of an organic binder and a solvent are sufficiently mixed and kneaded to produce a conductor paste for an inner wiring. A conductor paste for vias is produced in the same manner, with the same composition or a slightly changed composition ratio. It is also possible to add a small amount of the above-mentioned mixed powder of alumina and metal oxide to such a paste composition. By doing so, the familiarity between the substrate and the electrodes in the final laminate is improved.

  Next, a via hole is formed on the green sheet prepared above. Then, the via paste of the green sheet is filled with the via conductor paste. Next, after a wiring pattern is printed on the green sheets using the conductor paste for the inner layer wiring, these green sheets are laminated to form a laminate.

  The green body laminate and the green body laminate containing the oxide of the present invention prepared as described above are subjected to a binder removal treatment in a heating furnace at a temperature of about 600 ° C., and then further fired at a predetermined temperature. Thus, a sintered body and a multilayer substrate are obtained.

  The particle size of the alumina powder used as a raw material can be used as long as it is not extremely rough. However, in order to obtain a higher density at a lower temperature, the smaller the particle size, the better, and preferably 1 μm or less. On the other hand, considering the case of molding, if it is too small, it is difficult to handle. The particle size of the additives other than alumina may be slightly larger than this.

  Even if a metal oxide other than the above is mixed as a raw material of the material of the present invention, no particular problem occurs if its amount is sufficiently small. It is conceivable that such mixing is inevitably mixed with the starting material, mixed from the medium at the time of mixing, or added for the purpose of finely adjusting the properties of the material of the present invention. However, when the amount is large, sinterability may be reduced, dielectric characteristics may be deteriorated, and thermal conductivity may be reduced, which is not desirable.

  The conductor used for the multilayer substrate of the present invention is not particularly limited. However, in order to take advantage of the fact that it can be sintered at a low temperature, it is desirable that copper or silver having low resistance be a main component. When copper is used for the inner conductor, the melting temperature of copper is about 1080 ° C., so that the firing temperature needs to be lower than about 1070 ° C. or lower. When silver is used for the internal conductor, the melting temperature of silver is about 960 ° C., so that the firing temperature needs to be lower than about 950 ° C. or less. In the present invention, it is not impossible to use either of the inner conductors, but it is preferable to use silver because the binder can be removed in air.

  There is no particular limitation on the method for producing the molded article or green sheet, and for example, a uniaxial molding method, an isostatic pressing method, a doctor blade method, a calendar method, a roll coater method, and the like can be used.

  As the base film for holding the sheet, for example, a polyethylene resin, a polyester resin, paper, or the like can be used. Further, as a method of forming a via hole in the insulating sheet, for example, punching or laser processing can be used.

  As the atmosphere at the time of firing the molded body or the laminated body, Ag can be used for the internal conductor, so that the atmosphere may be usually used.

In the present invention, by mixing alumina powder and a specific oxide powder, sintering can be performed at a much lower temperature than ordinary alumina, and the production energy and the cost of a furnace used for production can be reduced. It is very advantageous. In addition, since firing can be performed at 950 ° C. or lower, simultaneous firing can be performed using low-resistance Ag as a conductor. As described above, the sintered body of the oxide ceramic material of the present invention is obtained only by mechanically mixing the respective metal oxides, molding and heating at a relatively low temperature. Therefore, the phase composition in the sintered body may be such that each metal oxide component may form a solid solution with each other in a small amount, but basically, each metal oxide or a compound in which two or more of the metal oxides react with each other. Is a mixture of Due to the high alumina content, the main phase is alumina (aluminum oxide, Al ₂ O ₃ ), but a mixture containing oxides other than alumina. Although a small amount of phases other than alumina are mixed, the thermal conductivity is high because the main phase is alumina, and when applied to multilayer substrates, etc., heat is generated on and inside such as power amplifiers. Even if an element is mounted, the heat is radiated through the substrate, and the temperature in the vicinity of the element does not become too high. Due to the high thermal conductivity, there is no need to particularly provide a thermal via. If thermal vias are used in combination, the heat dissipation is further improved. Of course, since the dielectric characteristics are also good, it can be used as a module on which elements other than the power amplifier are mounted. Also, the mechanical strength is as high as that of ordinary alumina except when used at high temperatures.

  FIG. 1 shows a perspective view of an example of a power amplifier module using a ceramic wiring board. That is, a power amplifier 2 and electronic components 3 such as capacitors, inductors and resistors are mounted on a ceramic multilayer wiring board 1. The power amplifier module is preferably incorporated in, for example, a motherboard of a mobile phone.

Hereinafter, the present invention will be specifically described with reference to examples.
(1) Method of measuring thermal conductivity The thermal conductivity of a sample is measured by irradiating a laser beam to one surface of a disk-shaped sample and measuring the thermal conductivity from the temperature rise on the opposite surface, the so-called laser flash method. It measured using.
(2) Measuring Method of Dielectric Loss The dielectric loss of the sample was measured at 1 MHz using an LCR meter 4284A manufactured by Hewlett-Packer, with gold electrodes formed on both sides of the disk-shaped sample by sputtering.

<Example 1>
As starting materials, aluminum oxide (Al ₂ O ₃ ) powder having a purity of 99.99% and a particle size of 0.5 μm, and powders of various metal oxides having a purity equal to or higher than the reagent grade were used. These were weighed so as to have the composition ratios shown in Table 1 and a total mass of 200 g, and were wet-mixed for 12 hours in a ball mill using alumina balls. After drying the powder, a small amount of polyvinyl alcohol aqueous solution was mixed and passed through a # 32 mesh sieve to granulate. This powder was uniaxially pressed into a mold having a diameter of 12 mm and a thickness of about 1 mm at a pressure of 1 t / cm ^{2 in} a mold. The obtained molded body was heated in air at 500 ° C. for 1 hour to perform binder out, and then fired at 900 ° C. to 1000 ° C. for 1 hour. The sintered density was calculated by measuring the size and mass of the sintered body.

  In addition, a plurality of the same sintered bodies were produced, pulverized, and the true density was measured using a pycnometer, and the relative sintered density was determined from the sintered density / true density. The results are shown in Table 1.

 As is clear from Table 1, the sample No. of alumina alone was used. Sample No. 1 or Sample No. 1 using only one type of various additives. In Nos. 2 to 6, almost no sintering was performed until firing at 1000 ° C.

When two types of additives are used in combination, the sample No. using Nb ₂ O ₅ and CuO was used. In No. 7, even at 950 ° C., the sintering considerably exceeded 90% density, and at 1000 ° C., sintering was close to the theoretical density. No. ₃ containing CuO and TiO ₂ . No. 11 using CuO and Bi ₂ O ₃ . No. 13 also showed an effect of accelerating sintering, but the density did not reach 90% even at 1000 ° C. No effect as good as 7 was seen. Assuming that silver is used for the internal electrode, the upper limit of the firing temperature is about 950 ° C. If the relative density at this time is 90% or less, mechanical strength and the like are considered to be insufficient. 11 and 13 are not practical.

When three types of additives were used in combination, No. ₂ was obtained by further adding TiO ₂ , Ag ₂ O, or Bi ₂ O ₃ to Nb ₂ O ₅ and CuO, which were effective with the two types of additives. In 17, 18, and 19, the density exceeded 95% when fired at 950 ° C., and sintering was possible at lower temperature. Further, even when Nb ₂ O ₅ and CuO are not contained, the No. _{2 of} CuO—TiO ₂ —Ag ₂ O addition. In No. 23, the density exceeded 90% after firing at 950 ° C. However, none of the other combinations reached a density of 90% even after firing at 1000 ° C.

When four types of additives were used in combination, No. ₂ was obtained by simultaneously adding TiO ₂ and Ag ₂ O to Nb ₂ O ₅ and CuO. At 27, the density at 900 ° C. firing exceeded 95%.

As described above, even if the alumina content is the same, Nb ₂ O ₅ and CuO are simultaneously contained, and in addition to Nb ₂ O ₅ and CuO, any one of TiO ₂ , Ag ₂ O, and Bi ₂ O ₃ is used. , And by simultaneously containing Nb ₂ O ₅ , CuO, TiO ₂ , and Ag ₂ O, sintering was possible at lower temperatures. Also, sintering was possible at a low temperature by simultaneously containing CuO, TiO ₂ and Ag ₂ O. Among them, the one having the best sinterability at the lowest temperature is the one containing Nb ₂ O ₅ , CuO, TiO ₂ and Ag ₂ O simultaneously. 27.

<Example 2>
As in Example 1, powders of aluminum oxide, niobium oxide, copper oxide, titanium oxide, silver oxide, and bismuth oxide were prepared, and aluminum oxide was 93% by mass, and the total of the remaining 5 components was 7% by mass. , Niobium oxide, copper oxide, titanium oxide, silver oxide, and bismuth oxide, assuming that the total was 100% by mass, these powders were mixed at 900 ° C. so that the mutual mass% was as shown in Table 2. Alternatively, it was fired at 950 ° C. for 2 hours to produce a sintered body, and its relative density was measured.

  Further, gold electrodes were formed on the upper and lower surfaces of the sintered body sample having a relative density exceeding 90% by sputtering, and the dielectric properties were evaluated. The results are shown in Table 2.

As is clear from Table 2, when only Nb ₂ O ₅ and CuO are included, the sintering density is slightly lowered even if the Nb ₂ O ₅ is too large or the CuO is too large, and the density of 90% or more is reduced. Even if obtained, the dielectric loss exceeded 5%. Therefore, Nb ₂ O ₅ is desirably 70% by mass or less, and CuO is desirably 60% by mass or less (Sample Nos. 1 to 6).

By adding any of TiO ₂ , Ag ₂ O, and Bi ₂ O _{3 to} Nb ₂ O ₅ and CuO, the density was increased at a lower temperature. However, if the amount of addition was too large, the density was lowered, In addition, the dielectric loss also increases, and 30% by mass or less of TiO ₂ (samples Nos. 7 to 11), 30% by mass or less of Ag ₂ O (samples 12 to 15), and 40% by mass of Bi ₂ O _3. The following was desirable (sample Nos. 16 to 19). Among the TiO ₂ , Ag ₂ O, and Bi ₂ O ₃ , Ag ₂ O had the largest densification effect, TiO ₂ was the _second largest, and Bi ₂ O ₃ had the smallest effect.

Furthermore, the highest density and the lowest dielectric loss were obtained by simultaneous addition of TiO ₂ and Ag ₂ O to Nb ₂ O ₅ and CuO. However, the simultaneous addition of TiO ₂ and Bi ₂ O ₃ and the simultaneous addition of Ag ₂ O and Bi ₂ O ₃ did not show a significant difference from the single addition.

<Example 3>
As in Example 2, powders of aluminum oxide, copper oxide, titanium oxide, and silver oxide were prepared. Aluminum oxide was 93% by mass, and the total of the remaining three components was 7% by mass. These powders were mixed and baked at 950 ° C. for 2 hours to obtain a sintered body so that the mutual mass% assuming that the total amount of silver oxide was 100 mass% was as shown in Table 3. The relative density was measured.

  Further, gold electrodes were formed on the upper and lower surfaces of the sintered body sample having a relative density exceeding 90% by sputtering, and the dielectric properties were evaluated. The results are shown in Table 3.

As is clear from Table 3, when CuO is 10% by mass to 90% by mass, TiO ₂ is 5% by mass to 60% by mass, and Ag ₂ O is 5% by mass to 40% by mass, it is relatively good. Characteristics were obtained. In particular, when CuO is 15% by mass to 75% by mass, TiO ₂ is 10% by mass to 50% by mass, and Ag ₂ O is 15% by mass to 35% by mass, the densification becomes remarkable and relatively Low dielectric loss was obtained.

<Example 4>
A powder was prepared by previously mixing each powder of Nb ₂ O ₅ , CuO, TiO ₂ , and Ag ₂ O at a mass ratio of 5.5: 2.7: 0.9: 0.9. This powder, alumina powder, and Mn ₃ O ₄ powder were mixed in a ball mill so as to have a mixing ratio shown in Table 4, calcined at 600 ° C. for 2 hours, and then pulverized again by a ball mill. In the same manner, a sintered body was prepared by firing at 900 ° C. or 950 ° C. for 2 hours, and its relative sintered density was determined. The thermal conductivity of the sintered body sample having a relative density exceeding 90% was measured by a laser flash method. In addition, a gold electrode was formed by sputtering, and the dielectric properties were evaluated. The results are shown in Table 4.

As is evident from Table 4, when the content of Al ₂ O ₃ exceeds 98%, the sinterability was not sufficient even when the composite additive was added. On the other hand, when the content of Al ₂ O ₃ is less than 80%, the sinterability is high, but both the dielectric properties and the thermal conductivity are reduced. Therefore, the content of Al ₂ O ₃ is preferably 80% or more and 98% or less, and more preferably 85% or more and 96% or less.

Next, when Al ₂ O ₃ was fixed at 92% and the composite additive was fixed at 8%, and when Mn ₃ O ₄ was added in the outer frame, the addition tended to improve the dielectric properties. As the amount increased, the sintering density decreased. Therefore, it is desirable that Mn ₃ O ₄ be contained in an amount of 0.1% by mass or more and 2% by mass or less.

In addition to the present example, the present inventors changed the ratio of Nb ₂ O ₅ , CuO, TiO ₂ , Ag ₂ O in the composite additive, or used CuO, TiO ₂ , Ag ₂ O as the composite additive. Similar experiments were performed using the system, but similar results were obtained for the Al ₂ O ₃ content and Mn ₃ O ₄ addition.

<Example 5>
In the same manner as in Example 1, powders of Al ₂ O ₃ , Nb ₂ O ₅ , CuO, TiO ₂ , and Ag ₂ O were mixed at a mass ratio of 93: 3: 2: 1.5: 0.5. The mixture was calcined at 600 ° C. for 2 hours and then pulverized again by a ball mill. The calcined powder was mixed with a polyvinyl butyral resin and butyl acetate to form a slurry, and a sheet was formed on a base film (polyphenyl sulfide) having a surface subjected to a release treatment by a doctor blade method.

For comparison, a slurry was prepared in the same manner as described above using only the Al ₂ O ₃ powder, and an alumina green sheet was formed on the base film. A slurry was prepared in the same manner as described above using a powder containing 50% by mass of Al ₂ O ₃ and 50% by mass of lead borosilicate glass, and a glass ceramic green sheet was formed on a base film.

  Next, an appropriate amount of an ethylcellulose-based resin and terpineol were added to a metal silver powder, and the mixture was sufficiently mixed and kneaded with a three-roll mill to prepare an Ag paste for an internal wiring and an Ag paste for a via, respectively.

  Next, a via hole having a diameter of 0.1 mm is punched in a predetermined portion of the green sheet by punching, and a necessary number of insulating sheets are filled with a via conductive paste, and a screen is formed on the sheet using the inner layer wiring paste. A wiring pattern was formed by a printing method. The insulating film was laminated by peeling the base film, and thermocompression bonded at 80 ° C. to obtain a laminated body.

  The obtained laminate was subjected to a binder removal treatment at 600 ° C. in the air in a heating furnace, and then fired at 920 ° C. for 2 hours. Separately from these, a sintered body was prepared from a laminated body containing no Ag conductor for measuring the thermal conductivity.

  First, the thermal conductivity of a sample containing no conductor was measured. As a result, it was 18 W / mk for the glass of the present invention and 2.5 W / mk for glass ceramics. Those using alumina had low mechanical strength and could not be measured. Then, the thermal conductivity was measured at a firing temperature of 1500 ° C. for the material using alumina, and was found to be 22 W / m · k.

  When the three-point flexural strength was measured without the conductor, the product of this example was 380 MPa, whereas the glass ceramic was 230 MPa. Those using alumina had low mechanical strength and could not be measured. Therefore, the three-point flexural strength of the material using alumina was measured at a firing temperature of 1500 ° C. and found to be 400 MPa. Therefore, the product of this example exhibited the same mechanical strength as alumina fired at 1500 ° C., even though the firing temperature was 920 ° C.

  Next, for those containing an Ag conductor, the conduction between the inner layer wiring and the via conductor was evaluated. As a result, conduction was obtained between those of the present invention and those using glass ceramics, but those of only alumina exhibited poor mechanical strength. It was too low to measure. Then, when the sintering temperature was set to 1500 ° C. in the case of using alumina, the Ag electrode was melted and no conduction was obtained.

  Next, when the power amplifier IC was mounted on the substrate of the present invention and the one using glass ceramics and operated, the one using glass ceramics had low heat conductivity, so that heat was radiated. Although the temperature rise was not sufficient and the temperature rise was intense, in the case of using the present invention, the temperature rise was suppressed low.

1 is a perspective view of a power amplifier module using a ceramic wiring board according to one embodiment of the present invention.

Explanation of reference numerals

DESCRIPTION OF SYMBOLS 1 Ceramic multilayer wiring board 2 Power amplifier 3 Electronic components, such as a capacitor, an inductor, and a resistor

Claims (17)

An oxide ceramic material containing aluminum oxide as a main component and at least one selected from the following A and B as a subcomponent.
A. Niobium oxide and copper oxide Copper oxide, titanium oxide and silver oxide The content of the main component in the whole oxide is 80% by mass or more and 98% by mass or less;
When the remaining component is only the subcomponent, the subcomponent is 2% by mass or more and 20% by mass or less,
2. The oxide ceramic material according to claim 1, wherein when another third component is contained in addition to the subcomponent, the total of the subcomponent and the third component is 2% by mass or more and 20% by mass or less. 2. The oxide ceramic material according to claim 1, wherein when the subcomponent is A, the ratio of niobium oxide and copper oxide is in the following ranges, respectively, when the total amount of the subcomponents is 100% by mass. 3.
40% by mass ≦ Niobium oxide ≦ 70% by mass
30 mass% ≤ copper oxide ≤ 60 mass%   2. The oxide ceramic material according to claim 1, wherein when the subcomponent is A, the oxide ceramic material further includes at least one selected from titanium oxide, silver oxide, and bismuth oxide. 3. The oxide ceramic material according to claim 4, wherein the ratio of niobium oxide, copper oxide, titanium oxide, silver oxide, and bismuth oxide is in the following range, when the total amount of the subcomponents is 100% by mass.
30% by mass ≦ Niobium oxide ≦ 70% by mass
10 mass% ≤ copper oxide ≤ 60 mass%
0 mass% ≤ titanium oxide ≤ 30 mass%
0% by mass ≦ Silver oxide ≦ 30% by mass
0 mass% ≤ bismuth oxide ≤ 40 mass% The ratio of copper oxide, titanium oxide, and silver oxide constituting the sub-component when the sub-component is B is in the following range, respectively, when the total amount of the sub-components is 100% by mass. Oxide ceramic materials.
10 mass% ≤ copper oxide ≤ 90 mass%
5 mass% ≤ titanium oxide ≤ 60 mass%
5% by mass ≦ Silver oxide ≦ 40% by mass   2. The oxide ceramic material according to claim 1, further comprising 0.1 to 2.0 mass% of manganese oxide, when the whole oxide is 100 mass%. 3.   The oxide ceramic material according to claim 1, wherein the oxide ceramic material is sintered at a relative density of 90% or more.   The oxide ceramic material according to claim 1, wherein the thermal conductivity of the oxide ceramic material is 5 W / m · k or more.   The oxide ceramic material according to claim 1, wherein the thermal conductivity of the oxide ceramic material is 10 W / mk or more.   2. The oxide ceramic material according to claim 1, wherein a dielectric loss at 1 MHz of the oxide ceramic material is 0.05 or less.   The oxide ceramic material according to claim 1, wherein the dielectric loss of the oxide ceramic material at 1 MHz is 0.01 or less.   2. The oxide ceramic material according to claim 1, wherein the oxide ceramic material is a mixture of metal or metal oxide material particles, molded, and fired at a temperature of 950 ° C. or less.   2. The oxide ceramic material according to claim 1, wherein the oxide ceramic material is obtained by mixing a metal or metal oxide material particles, calcining and pulverizing, then molding and firing at a temperature of 950 ° C. or lower. . An insulating layer made of an oxide ceramic material containing aluminum oxide as a main component and at least one selected from the following A and B as subcomponents,
A. Niobium oxide and copper oxide A ceramic substrate having a conductor containing copper oxide, titanium oxide and silver oxide as main components at least in its inner layer. An insulating layer made of an oxide ceramic material containing aluminum oxide as a main component and at least one selected from the following A and B as subcomponents,
A. Niobium oxide and copper oxide A multilayer ceramic device comprising at least an inner layer of a conductor mainly composed of copper oxide, titanium oxide and silver oxide. An insulating layer made of an oxide ceramic material containing aluminum oxide as a main component and at least one selected from the following A and B as subcomponents,
A. Niobium oxide and copper oxide A power amplifier module in which a power amplifier element is mounted on a ceramic substrate or a multilayer ceramic device having at least an inner layer of a conductor mainly composed of copper oxide, titanium oxide, and silver oxide.

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