JP4701761B2 - Ceramic multilayer substrate and power amplifier module using the same - Google Patents

Description

  The present invention relates to a ceramic multilayer substrate using an electrode mainly composed of silver and a power amplifier module using the same.

Conventionally, a multilayer ceramic substrate for mounting a semiconductor IC or the like is roughly divided into a high temperature firing type HTCC (High Temperature Co-fired Ceramics) system and a low temperature firing type LTCC (Low Temperature Co-fired Ceramics) system multilayer ceramic substrate. Can be classified. The base material of the HTCC multilayer ceramic substrate uses inorganic powder having heat resistance such as Al ₂ O ₃ , AlN, BeO, SiC—BeO. These ceramic materials are produced by mixing and molding the inorganic powder as a main component and then firing at a high temperature of 1500 ° C. or higher. For this reason, Mo or W having a high melting point is used as a conductor material for wiring formed inside the HTCC multilayer ceramic substrate. However, Mo and W have a defect that the conductivity is low as a conductor, and silver and copper having high conductivity have a low melting point, and are melted by firing at the firing temperature of the HTCC-based multilayer ceramic substrate. It cannot be used as a wiring conductor.

  On the other hand, the demand for lower resistance of the conductor of the multilayer ceramic substrate increases with the demand for module parts in the high frequency range, and in order to satisfy these demands, ceramic raw materials such as alumina and forsterite are used at a temperature at which silver and copper do not melt. What can be sintered is an LTCC multilayer ceramic substrate. This LTCC-based multilayer ceramic substrate is also called a low-temperature fired multilayer ceramic substrate, and can be fired at a low temperature by mixing a glass material having a low melting point with the ceramic material. For example, lead borosilicate glass + alumina system , Borosilicate glass + cordierite system and various other composition systems.

  Insulator materials having these compositions are adjusted so that they can be fired at a temperature of 1000 ° C. or lower in order to enable simultaneous firing with a metal having high conductivity such as silver or copper. As a result, high conductivity silver or copper can be used as the inner conductor, and this LTCC multilayer ceramic substrate (low temperature firing type multilayer ceramic substrate) is currently used as a multilayer ceramic substrate capable of realizing high-density mounting used in a high frequency range. It is becoming mainstream.

  However, since LTCC materials using these glasses contain a large amount of glass having a relatively low thermal conductivity, the inherent high thermal conductivity of ceramics such as alumina is hindered. When the thermal conductivity of the ceramic multilayer substrate decreases, when a power amplifier module or the like is manufactured by mounting semiconductor elements with large heat generation such as a power amplifier at a high density, the temperature rises remarkably and cannot be used practically. This tendency is particularly remarkable in portable electronic devices and the like that are strongly required to be downsized.

In contrast, LTCC materials have been developed that can be fired at low temperatures while minimizing the amount of glass having a low melting point and taking advantage of the inherent high thermal conductivity of ceramics. These include a mixture of bismuth oxide, niobium oxide, and aluminum oxide to which copper oxide and vanadium oxide as sintering aids are added (for example, see Patent Document 1), or copper oxide and niobium oxide are simultaneously added to aluminum oxide. The thing (for example, refer patent document 2) is disclosed.
JP 2000-109363 A JP 2004-256384 A

  However, in the conventional configuration, when an oxide such as a copper oxide that exhibits a eutectic reaction with silver is contained in the body to be fired, which is an LTCC multilayer ceramic substrate, the disappearance of silver is sufficiently suppressed. Had the problem of not being able to.

  The present invention solves the above-mentioned conventional problems, and provides a ceramic multilayer substrate having good sinterability while suppressing disappearance of an electrode mainly composed of silver, and a power amplifier module using the same. It is the purpose.

In order to solve the above-mentioned conventional problems, the present invention provides a ceramic multilayer substrate produced by alternately laminating inorganic oxide layers and electrode layers mainly composed of silver and integrally firing at a temperature of 940 ° C. or lower. The inorganic oxide layer is made of a ceramic composition, and the secondary components of the ceramic composition include copper oxide, silver oxide, niobium oxide and titanium oxide, and the total of the secondary components of the ceramic composition is 100% by weight. In terms of oxide, 10 wt% ≦ niobium oxide (Nb ₂ O ₅ ) ≦ 60 wt%, 10 wt% ≦ copper oxide (CuO) ≦ silver oxide (Ag ₂ O), 0 wt% <titanium oxide (TiO ₂ ) ≦ 50 wt%, 45 wt% ≦ silver oxide (Ag ₂ O) ≦ 60 wt%, and the content of silver oxide (Ag ₂ O) is greater than or equal to the content of copper oxide (CuO) Characteristic ceramic multilayer substrate One in which the.

  A ceramic multilayer substrate and a power amplifier module using the same according to the present invention include a ceramic multilayer substrate having good sinterability at low temperatures while suppressing disappearance of an electrode mainly composed of silver, and a power amplifier module using the same Can be provided.

(Embodiment 1)
Hereinafter, a ceramic multilayer substrate and a power amplifier module using the same according to Embodiment 1 of the present invention will be described with reference to the drawings.

  1 (a) to 1 (c) are cross-sectional views for explaining a method for manufacturing a ceramic multilayer substrate in accordance with Embodiment 1 of the present invention, and FIG. 2 shows a power amplifier module using the ceramic multilayer substrate. It is sectional drawing.

  In the first embodiment, the structure of the ceramic multilayer substrate with a capacitor and a coil built in the inner layer will be described as an example while explaining the manufacturing method.

  First, as a ceramic composition which is the main component of the inorganic oxide layer 202, the average particle size: 0.05 to 5 μm of aluminum oxide of 90 to 96% by weight, niobium oxide of 0 to 6.0% by weight and titanium oxide 0 to 5.0% by weight, an average particle size as a subcomponent of the inorganic oxide layer 202; 0.05 to 5 μm of copper oxide of 0.4 to 3.5% by weight, and silver oxide of 1.2 to 6.0 wt% was blended.

  At this time, niobium oxide and titanium oxide are added in order to control the sinterability, and the main component of the ceramic composition can be composed of only aluminum oxide.

  Furthermore, after blending 50 to 300 parts by weight of water with respect to 100 parts by weight of the inorganic material composition which is a mixture of the main component and the subcomponent, the mixture is put into a ball mill and further dispersed with high purity alumina of 1 to 5 mmφ. Using as a media, ball mill mixing was performed for 12 to 72 hours. Thereafter, the ceramic slurry made of the inorganic material composition was taken out from the ball mill and dried.

  Next, with respect to 100 parts by weight of the dried inorganic material composition, a resin binder such as PVB; 5 to 15 parts by weight, a dispersion medium such as butyl acetate and alcohol; 40 to 120 parts by weight, plastic such as DBP and BBP Agent: 2 to 12 parts by weight, and if necessary, a small amount of an antifoaming agent and a dispersing agent are blended. Using a 10 mmφ high-purity alumina ball as a dispersion medium, ball mill dispersion is again performed for 12 to 72 hours to produce a ceramic slurry. did.

  Next, the ceramic slurry is applied to a predetermined thickness on a carrier film such as a PET film which has been subjected to a release treatment using a sheet molding machine such as a die coating apparatus, and then dried in a drying furnace to obtain FIG. The ceramic green sheet 101 shown to a) was produced.

  Next, the ceramic green sheet 101 is punched at a predetermined position by punching or laser processing as necessary, and then drilled using a conductive paste mainly composed of silver by screen printing or the like. The via hole 102 is filled and applied to form the via electrode 102.

  Thereafter, a wiring electrode 103 having a circuit pattern is formed on the ceramic green sheet 101 by a screen printing method using a conductive paste mainly composed of silver.

  Next, the ceramic green sheets 101 each having wiring electrodes 103 printed and formed are stacked and pressed while being aligned so as to have a predetermined design as shown in FIG. The laminated body 104 in which the ceramic green sheets 101 and the wiring electrodes 103 are alternately laminated as shown in FIG. By setting the size of the laminate 104 to usually 50 to 200 mm □, a large number of predetermined ceramic multilayer substrates 201 can be produced in a matrix.

  Further, the capacitor 105 can be built in by disposing the wiring electrode 103 having a predetermined area on the inner layer portion of the laminate 104 so as to face each other with the ceramic green sheet 101 interposed therebetween.

  It is also possible to incorporate a coil 107 having a spiral structure through a via electrode 102 in which the wiring electrode 103 is formed on the ceramic green sheet 101. By incorporating these capacitors 105 and coils 107, a ceramic multilayer substrate 201 capable of high-density mounting can be realized.

  Next, a surface layer electrode 106 is formed on the laminate 104 using a conductive paste containing silver as a main component. Thereafter, the laminated body 104 is pressed with a predetermined pressure in the vertical direction and laminated and pressure-bonded.

In addition, it is preferable that the temperature at the time of this lamination | stacking and pressurization shall be normal temperature-100 degreeC, and pressure shall be 20-1000 kgf / cm < ² >.

  Thereafter, as shown in FIG. 1 (c), the laminated body 104 that has been laminated and pressure-bonded is cut into pieces into the shape of a predetermined laminated ceramic substrate 201. The separated laminated body 104 is heated to 400 to 600 ° C. The binder removal process is performed at the temperature.

  Next, as a firing step, firing is performed in an atmospheric atmosphere with a maximum holding temperature of 850 to 900 ° C. and a holding time of 1 to 30 hours at the maximum temperature.

  Further, the manufacturing method of the ceramic multilayer substrate 201 so far does not greatly differ from the manufacturing method of a normal LTCC ceramic multilayer substrate except for the material composition of the inorganic oxide layer 202.

  The ceramic multilayer substrate 201 manufactured by such a manufacturing method is composed of the inorganic oxide layer 202 and the wiring electrode 103 mainly composed of silver. In particular, the ceramic multilayer substrate 201 in the first embodiment is an inorganic oxide layer. It is characterized by 202 material composition. The inorganic oxide layer 202 includes aluminum oxide, which is a ceramic composition, as a main component, and includes copper oxide and silver oxide as subcomponents.

  In particular, when the inorganic oxide layer 202 to which silver oxide or silver is added and the wiring electrode 103 containing silver as a main component are integrally fired, the copper oxide added as a subcomponent is contained in the silver electrode constituting the wiring electrode 103. It was found that the silver electrode constituting the wiring electrode 103 can be prevented from disappearing by reacting with silver or silver oxide present in the inorganic oxide layer 202 before diffusing into the metal.

  Further, as a result of observing the cross section of the ceramic multilayer substrate 201 configured as described above, the disappearance of the silver electrode constituting the wiring electrode 103 was not recognized up to the end. Thus, even when the inorganic oxide layer 202 containing copper oxide is formed, the wiring electrode 103 using silver having high conductivity is incorporated in a predetermined size and shape by adopting the above-described configuration. Therefore, the ceramic multilayer substrate 201 having excellent high frequency characteristics can be realized.

  The relative density of the ceramic multilayer substrate 201 was 90% or more.

  Further, in such a ceramic multilayer substrate 201, the inorganic oxide layer 202 is composed by increasing the content of aluminum oxide, which is the main component of the ceramic composition, and devising the composition of subcomponents. Therefore, it is possible to realize the ceramic multilayer substrate 201 that is most suitable for a small power amplifier module or the like on which a semiconductor device having high heat generation is mounted. it can.

  As shown in FIG. 2, this power amplifier module can realize a small power amplifier module 206 by mounting a semiconductor component such as the power amplifier 205 on the surface layer of the ceramic multilayer substrate 201 manufactured by the above method. Compared to conventional power amplifier modules, reducing the number of thermal vias increases the degree of freedom in circuit design and eases the restrictions on wiring space, thereby further reducing the size of various modules that generate heat. Therefore, it is possible to reduce the size and weight of various electronic devices.

  Further, by forming the ceramic composition from a metal oxide and glass, it is possible to achieve lower temperature sintering and to make the inorganic oxide layer 202 an insulator or dielectric having excellent material characteristics. Thus, the ceramic multilayer substrate 201 suitable for thermal conductivity and high frequency characteristics can be configured.

  In order to realize such a configuration, the material composition of the metal oxide includes aluminum oxide, magnesium oxide, forsterite, steatite, silicon oxide, bismuth oxide-niobium oxide oxide, barium titanate, and titanium oxide. At least one of them is selected, and the glass material composition is selected by selecting at least one selected from silicon oxide, boron oxide and barium oxide, and at least zinc oxide, calcium oxide and strontium oxide. It is possible to realize the LTCC ceramic multilayer substrate 201 including the inorganic oxide layer 202 having characteristics.

  Hereinafter, the present invention will be described more specifically with reference to examples.

(Example 1)
Hereinafter, the ceramic multilayer substrate in Example 1 of the present invention will be described.

  FIG. 3 is a cross-sectional view of the multilayer resonator according to the first embodiment of the present invention, and FIG. 4 is a circuit diagram for explaining a method for evaluating the multilayer resonator.

As a starting material of the ceramic composition forming the inorganic oxide layer 202, purity: 99.99%, average particle diameter: 1.0 μm aluminum oxide (Al ₂ O ₃ ), and purity as shown in (Table 1) ; 99.99%, average particle size; Seven types of glass with different softening points of silicon oxide, boron oxide, barium oxide, calcium oxide, strontium oxide, zinc oxide and aluminum oxide with 0.2 to 2 μm as raw materials did. Further, copper oxide (CuO) and silver oxide (Ag ₂ O) having an average particle diameter of 0.1 to 5 μm were prepared as subcomponents of the inorganic oxide layer 202, respectively.

  55% by weight of the aluminum oxide, 42% by weight of the glass shown in (Table 1), 1.5% by weight of copper oxide and 1.5% by weight of silver oxide were blended to obtain an inorganic material composition (No. 1-No.7).

  This inorganic material composition: 100 parts by weight, 200 parts by weight of water was blended, and ball mill mixing using 2 mmφ zirconia was performed for 24 hours.

  Next, the inorganic material composition after drying: 8 parts by weight of polyvinyl butyral resin as a resin binder, 80 parts by weight of butyl acetate as a dispersion medium, and 6 parts of benzyl butyl phthalate (BBP) as a plasticizer with respect to 100 parts by weight A ceramic slurry was prepared by blending parts by weight and performing ball mill dispersion for 48 hours using 10 mmφ zirconia.

  Next, using the ceramic slurry produced in this way, it was applied as a ceramic green sheet on a carrier film such as a PET film using a die coating apparatus. The temperature of the drying furnace for drying the ceramic slurry is 80 to 100 ° C., and the traveling speed of the carrier film is 10 m / min. It was. The thickness of the ceramic green sheet obtained by drying under such drying conditions was 40 μm.

  In order to evaluate the sinterability of the inorganic oxide layer 202 formed using this ceramic green sheet, 34 ceramic green sheets were laminated and pressed into a disk shape with a 10 mmφ die.

  The laminate punched out in the shape of a disc was subjected to a binder removal treatment at a heating rate of 50 ° C./hr, a holding temperature of 500 ° C., and a holding time of 4 hours. Then, it baked in air | atmosphere with the temperature increase rate of 400 degreeC / hr, the calcination temperature; 950 degreeC, and holding time; 2 hours. The sintered density of the obtained sintered body was evaluated by the Archimedes method.

  Further, a plurality of the same sintered bodies were produced, pulverized, and the true density was measured using a pycnometer, and the relative density was obtained from the sintered density / true density. The sinterability when the relative density was 90% or more was marked with ◯, and when it was less than 90%, it was marked with x. Table 1 shows the evaluation results of the sinterability.

  From the results of (Table 1), although the composition (No. 4) using the glass having a softening point of 880 ° C. had a problem in sinterability, it was prepared using a glass having a softening point of 860 ° C. or lower. It was found that the inorganic oxide layer 202 has a sinterability that can be practically used.

  Next, as the ceramic composition, a metal oxide composed of aluminum oxide having a purity of 99.99% and an average particle diameter of 1.0 μm, and No. 1 in (Table 1). The glass with a softening point of 840 ° C. shown in FIG. 6 is prepared, and copper oxide and silver oxide having an average particle diameter of 0.1 to 5 μm are prepared as subcomponents, and 11 kinds of material compositions shown in (Table 2) are provided. An inorganic material composition was prepared.

  Then, a λ / 4 type laminated resonator 401 as shown in FIG. 3 was manufactured by the same manufacturing method as described above. In this λ / 4 type laminated resonator 401, after cutting the ceramic green sheet 101 into 70 × 70 mm, a resonator electrode 402 is printed on one layer of the ceramic green sheet 101 by using silver paste to produce an electrode pattern. did.

  Thereafter, 34 ceramic laminates including the ceramic green sheet 101 on which the resonator electrode 402 was formed were laminated and pressure-bonded to produce a ceramic laminate. After this ceramic laminate was separated into pieces with a resonance frequency of 2.5 GHz of the laminated resonator 401, these separated ceramic laminates were heated at a heating rate of 50 ° C./hr, holding temperature; The binder removal treatment was performed at 500 ° C. and holding time: 4 hours.

  Then, after firing in the air at a heating rate of 400 ° C./hr, firing temperature; 900 ° C. and 940 ° C., holding time; 2 hr, after taking out and forming the extraction electrode 404 and the shield electrode 405 using a silver paste, The laminated resonator 401 was able to be manufactured by baking using a belt furnace.

  The resonator electrode 402 of the multilayer resonator 401 manufactured in this way is disposed at the center of the multilayer resonator 401 and is surrounded by the inorganic oxide layer 403, and the shield electrode 405 is formed on the outermost layer. In addition, an extraction electrode 404 connected to the resonator electrode 402 is provided.

  The resonance frequency of the laminated resonator 401 depends on the length of the laminated resonator 401 if the relative dielectric constant of the inorganic oxide layer 403 is known.

  The Q value which is the loss coefficient of the multilayer resonator 401 manufactured in this way was evaluated.

  As shown in FIG. 4, the evaluation method is such that the impedance is adjusted to be close to 50Ω by inserting a capacitor 407 between the laminated resonator 401 and the network analyzer 406, and the network analyzer 406 (Agilent 8720ES) is adjusted. And measured.

  Here, when the silver electrode forming the resonator electrode 402 of the multilayer resonator 401 disappears, the electrode width of the resonator electrode 402 becomes narrower, and a decrease in the Q value, which is a loss coefficient, is observed. The disappearance degree of the silver electrode due to the copper oxide contained in the inorganic oxide layer 403 of the silver electrode can be accurately evaluated. (Table 2) shows the evaluation results of these relative densities and the Q value of the laminated resonator 401.

  From the result of (Table 2), in the sample (No. 8) which does not contain copper oxide and silver oxide, the relative density was less than 90% even at 940 ° C. When the relative density was less than 95%, the Q value of the laminated resonator 401 was not measured, but when the cross section was observed, the disappearance of the silver electrode was not observed.

  In addition, the sample (No. 9) to which 1% by weight of copper oxide was added showed good sinterability, but the Q value of the laminated resonator 401 was extremely low, and it was particularly difficult to measure at 940 ° C. firing. there were. When the cross-sectional structure of the laminated resonator 401 was observed, it was found that the end portion of the silver electrode disappeared.

  On the other hand, the Q value of the laminated resonator 401 is increased by adding silver oxide, and the Q value is 900 ° C. and 940 ° C. firing particularly by adding silver oxide of the same weight% or more as copper oxide. It became 100 or more and showed a stable Q value (No. 10 to 13). When the cross section of this laminated resonator 401 was observed, the disappearance of the silver electrode was not recognized. Moreover, the same tendency was shown also about the sample (No. 14-18) which added copper oxide 2weight%.

(Example 2)
Hereinafter, the ceramic multilayer substrate in Example 2 of the present invention will be described.

  The following three types of metal oxides were prepared as raw materials for the ceramic composition of the inorganic oxide layer 202. (1) Purity: 99.99%, average particle size: 0.4 μm magnesium oxide powder, (2) Purity: 99.99%, average particle size: 0.9 μm forsterite powder, (3) Purity: 99 99%, average particle size; 0.2 μm barium titanate powder.

  Further, a glass (No. 6) having a softening point of 840 ° C. shown in (Table 1) is prepared, and copper oxide and silver oxide are prepared as subcomponents of the inorganic oxide layer 202. (Table 3) to (Table 3) The materials were blended so as to have 15 material compositions shown in 5).

  Thereafter, the relative density and the Q value of the laminated resonator 401 were measured in the same manner as in Example 1. The evaluation results are shown in (Table 3), (Table 4), and (Table 5).

  From the results of (Table 3), (Table 4), and (Table 5), the sinterability at 900 ° C. or higher was good for all the samples. Further, when the silver oxide was less than 1.4% by weight, which is the same content as copper oxide, the Q value of the resonator showed a low value (No. 19, 20, 24, 25, 29, 30). On the other hand, when the silver oxide is 1.4 wt% or more in the same content as the copper oxide, the Q value of the laminated resonator 401 shows a good value, and the change in characteristics due to the firing temperature is also small (No .21-23, No.26-28, No.31-33).

(Example 3)
Hereinafter, the ceramic multilayer substrate in Example 3 of the present invention will be described.

  As raw materials for the ceramic composition of the inorganic oxide layer 202, a bismuth oxide-niobium oxide oxide, aluminum oxide, and vanadium oxide having a purity of 99.99% and an average particle diameter of 0.2 to 1 μm are prepared, and an inorganic oxide is prepared. As subcomponents of the physical layer 202, copper oxide and silver oxide were prepared, and five kinds of material compositions shown in (Table 6) were blended. Thereafter, the relative density and the Q value of the laminated resonator 401 were measured in the same manner as in Example 1. (Table 6) shows the evaluation results of the relative density and the Q value of the laminated resonator 401.

  From the results of (Table 6), when all the samples have good sinterability at 900 ° C. or higher and the silver oxide is less than 0.6% by weight, which is the same content as copper oxide, the laminated resonator 401 has The Q value was not measurable (No. 34, No. 35).

  In addition, in the material composition in which niobium oxide and copper oxide coexist, the disappearance of the reaction of the silver electrode occurred. However, by making silver oxide the same content as copper oxide by 0.6% by weight or more, laminated resonator 401 The Q value of the sample showed a good value, and there was little change due to the firing temperature (No. 36 to 38).

Example 4
Hereinafter, the ceramic multilayer substrate in Example 4 of the present invention will be described.

  As a raw material of the ceramic composition of the inorganic oxide layer 202, purity: 99.99%, average particle size: 0.3 μm aluminum oxide and purity: 99.99%, average particle size: 0.2-2 μm oxidation Niobium was prepared, and copper oxide and silver oxide were prepared as subcomponents of the inorganic oxide layer 202, and nine types of inorganic material compositions shown in (Table 7) were blended.

  Thereafter, the relative density and the Q value of the laminated resonator 401 were measured in the same manner as in Example 1. In this example, the difference from Example 1 is that the balls used during mixing and dispersion are high-purity alumina, and the firing temperature is the maximum temperature of 920 ° C. and 940 ° C., and each holds for 3 hours. It ’s been done. In addition to the evaluation of the relative density and the Q value of the laminated resonator 401, the thermal conductivity of the disk-shaped sample used for the measurement of the relative density was measured. Specifically, the measurement was performed using a so-called laser flash method in which laser light was irradiated on one surface of a disk-shaped sample and the thermal conductivity was measured from the temperature increase on the opposite surface. Table 7 shows the evaluation results of the relative density, the Q value of the laminated resonator 401, and the thermal conductivity.

  From the results of (Table 7), in the samples (No. 39, No. 40) in which the aluminum oxide content is less than 90% by weight, the sinterability is good but the thermal conductivity is 15 W / m. It was as low as less than K. On the other hand, samples (No. 41 to No. 44) in which the content of aluminum oxide is in the range of 90 to 96% by weight ensure sinterability at 940 ° C. and have a thermal conductivity of 15 W / m. It was as good as K or more. Moreover, the sample (No. 45) in which the content weight of aluminum oxide was 98% by weight could not secure the sinterability at 940 ° C., and the thermal conductivity was low. Furthermore, even if the content of aluminum oxide was 90% by weight, the sample (No. 46) that did not contain niobium oxide could not secure sinterability at 940 ° C. and had a low thermal conductivity. In contrast, the sample added with copper oxide and niobium oxide (No. 47) can secure sinterability at 920 ° C. and has a thermal conductivity of 15 W / m. Good at K or higher.

(Example 5)
Hereinafter, a ceramic multilayer substrate in Example 5 of the present invention will be described.

  FIG. 5 shows a photomicrograph showing the disappearance state of the silver electrode in the inner layer portion of the ceramic multilayer substrate in this example.

  As a raw material of the ceramic composition of the inorganic oxide layer 202, purity: 99.99%, average particle size: 0.3 μm aluminum oxide and purity: 99.99%, average particle size: 0.2-2 μm oxidation Niobium and titanium oxide were prepared, copper oxide and silver oxide were prepared as subcomponents of the inorganic oxide layer 202, and 33 kinds of inorganic material compositions shown in (Table 8) were blended. The content weight of aluminum oxide when the entire inorganic oxide layer 202 was 100% by weight was fixed at 94% by weight.

  Thereafter, the relative density, the Q value of the laminated resonator 401, and the thermal conductivity were measured in substantially the same manner as in Example 4. The difference from Example 4 is only the firing conditions, in that the holding was performed at a maximum temperature of 900 ° C. and 920 ° C. for 8 hours, respectively. Table 8 shows the evaluation results of the relative density, the Q value of the laminated resonator 401, and the thermal conductivity.

  From the results of (Table 8), in the samples (No. 48, No. 49) in which the content of silver oxide is 10% by weight and 20% by weight, the Q value of the laminated resonator 401 is smaller than 100. On the other hand, in the sample (No. 50 to No. 56) in which the content of silver oxide was 30 to 60% by weight, the Q value of the laminated resonator 401 was a value larger than 100. Further, the sample (No. 57) having a silver oxide content of 65% by weight had insufficient sinterability at 900 ° C. From this result, the content of silver oxide is preferably 30 to 60% by weight.

  Next, in the samples (No. 58, No. 69, No. 70) in which the content of copper oxide was 5% by weight, the sinterability at 900 ° C. was insufficient. From this result, the content of copper oxide is preferably 10% by weight or more.

  Moreover, in the sample (No. 58) in which the content of titanium oxide is 55% by weight, the sinterability at 900 ° C. is insufficient, and the content of titanium oxide is preferably 50% by weight or less.

  In addition, in the samples (No. 62, No. 78) in which the niobium oxide content is 5% by weight and the sample (No. 69) in which the content weight is 65% by weight, the sinterability at 900 ° C. is insufficient. Met. Accordingly, the content of niobium oxide is preferably 10 to 60% by weight. For other samples, the relative density exceeds 90% at 900 ° C., the Q value of the laminated resonator 401 is 100 or more, and the thermal conductivity is 15 W / m. A good characteristic value of K or more was shown. Moreover, the cross-sectional photograph of the laminated resonator 401 of the sample (No. 68) baked at 920 ° C. is shown in FIG. The disappearance of the silver electrode was not recognized at all including the edge.

  Furthermore, with the samples (No. 79, No. 80), the Q value of the laminated resonator 401 could not be measured. A cross-sectional photograph of the laminated resonator 401 of this sample (No. 80) is shown in FIG. 5B, and a sectional photograph of the laminated resonator 401 of the sample (No. 79) is shown in FIG. In the sample (No. 80) having a silver oxide-containing weight less than that of copper oxide, the end of the silver electrode disappeared, and in the sample (No. 79) not containing silver oxide, no silver electrode remained.

(Example 6)
Hereinafter, a power amplifier module using the ceramic multilayer substrate 201 will be described in Embodiment 6 of the present invention.

  First, using the inorganic material composition of the sample (No. 72) in Example 5, a ceramic multilayer substrate 201 having a plurality of capacitors 105 and coils 107 having predetermined characteristic values was fabricated.

  Next, a power amplifier module 206 was fabricated by mounting a power amplifier 205 on the upper surface of the ceramic multilayer substrate 201. Description of mounting other passive components is omitted. In addition, it was 19.0 W / m * K when the heat conductivity of the sample (No. 72) was measured. The size of the power amplifier module 206 is 8 mm × 6 mm × 1.5 mm.

  For comparison, an LTCC ceramic multilayer substrate is manufactured using 50 parts by weight of aluminum oxide and 50 parts by weight of borosilicate glass, and a power amplifier 205 is mounted on the upper part to manufacture a power amplifier module (comparative example). did. The thermal conductivity of the material used for the LTCC ceramic multilayer substrate was 2.0 W / m · K.

  Next, 5 W of electric power was applied to each power amplifier 205, and the temperature rise on the surface of the power amplifier 205 was examined with a non-contact thermometer.

  As a result, in the power amplifier module of the comparative example, the temperature of the surface portion of the power amplifier 205 increased with time and exceeded 150 ° C., and there was a concern that the power amplifier 205 malfunctioned. In order to suppress such heat generation, there is a means of providing a thermal via and promoting heat dissipation from the thermal via, but the module shape has become a large size of 13 mm × 9 mm × 1.8 mm.

  On the other hand, the power amplifier module 206 using the sample (No. 72) having high thermal conductivity could be suppressed to an exothermic temperature of 50 ° C. or less without arranging a thermal via or the like.

  The ceramic multilayer substrate and the power amplifier module using the ceramic multilayer substrate according to the present invention have good sinterability at low temperatures while suppressing the disappearance of the silver electrode, so that the ceramic multilayer substrate used for small electronic devices It is also useful as a power amplifier module.

(A)-(c) is sectional drawing for demonstrating the manufacturing method of the ceramic multilayer substrate in Embodiment 1 of this invention, respectively. Cross section of the power amplifier module (A), (b) is a side cross-sectional view and a front cross-sectional view of the multilayer resonator according to the first embodiment of the present invention. Circuit diagram for explaining the resonator evaluation method (A)-(c) is a microscope picture which shows the disappearance state of the silver electrode in the inner layer part of the ceramic multilayer substrate in Example 5 of this invention, respectively.

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 Ceramic green sheet 102 Via electrode 103 Wiring electrode 104 Laminated body 105 Capacitor 106 Surface layer electrode 107 Coil 201 Ceramic multilayer substrate 202 Inorganic oxide layer 205 Power amplifier 206 Power amplifier module 401 Multilayer resonator 402 Resonator electrode 403 Inorganic oxide layer 404 Extraction electrode 405 Shield electrode 406 Network analyzer 407 Capacitor

Claims (6)

In a ceramic multilayer substrate produced by alternately laminating inorganic oxide layers and electrode layers mainly composed of silver and integrally firing at a temperature of 940 ° C. or lower,
The inorganic oxide layer is Ri Do a ceramic composition,
When the subcomponent of the ceramic composition contains copper oxide, silver oxide, niobium oxide and titanium oxide, and the total of the subcomponent of the ceramic composition is 100% by weight,
In terms of oxide, 10 wt% ≦ niobium oxide (Nb ₂ O ₅ ) ≦ 60 wt%, 10 wt% ≦ copper oxide (CuO) ≦ silver oxide (Ag ₂ O), 0 wt% <titanium oxide (TiO ₂ ) ≦ 50 wt%, 45 wt% ≦ silver oxide (Ag ₂ O) ≦ 60 wt%, and the content of silver oxide (Ag ₂ O) is more than the content of copper oxide (CuO) Multilayer board. The ceramic composition is composed of a metal oxide and glass, and the metal oxide includes at least one selected from the following A, and the glass includes silicon oxide, boron oxide, barium oxide, and B The ceramic multilayer substrate according to claim 1, comprising at least one selected from the above.
A. Aluminum oxide, magnesium oxide, forsterite, steatite, silicon oxide, bismuth oxide-niobium oxide oxide, barium titanate, titanium oxide Zinc oxide, calcium oxide, strontium oxide The ceramic multilayer substrate according to claim 2, wherein the glass has a softening point of 860 ° C. or lower. 2. The ceramic multilayer substrate according to claim 1, wherein the main component of the ceramic composition is aluminum oxide, and a content ratio of the total amount of the aluminum oxide in the ceramic composition is 90 to 96 wt% . The ceramic multilayer substrate according to any one of claims 1 to 4 , wherein the inorganic oxide layer has a thermal conductivity of 15 W / m · K or more. A power amplifier module in which at least a power amplifier element is mounted on the ceramic multilayer substrate according to any one of claims 1 to 4 .