JP4428962B2 - Electromagnetic wave absorber and high frequency circuit package using the same - Google Patents

Description

  The present invention relates to an electromagnetic wave absorber used in a high frequency band such as a microwave and a millimeter wave, and a high frequency circuit package provided with the electromagnetic wave absorber. In particular, the present invention relates to a high-frequency circuit package used for a mobile phone, an antenna switch module, and the like.

Hermetic sealing of the high-frequency circuit package is usually performed by sealing by attaching a rectangular lid made of metal or ceramics such as the package base. Since a rectangular parallelepiped cavity is formed inside such a high-frequency circuit package, cavity resonance occurs inside the high-frequency circuit package as in the rectangular cavity resonator . Since air sinus resonance occurs at a frequency band higher than the cutoff frequency determined by the dimensions of the internal high-frequency circuit, when mounting a high-frequency semiconductor element or other circuit elements that operate in this frequency band on the package for high frequency circuit, the empty dong by reducing the size, the cutoff frequency element are sufficiently higher than the frequency band to operate. However, the operating frequency of the elements in this way is accompanied to higher frequencies, better frequency element cavity resonance than the frequency band operates occurs a problem that decreases. In recent years, in order to solve this problem, there is a method for suppressing cavity resonance by attaching an electromagnetic wave absorber to a part or inside of a high frequency circuit package and absorbing electric field energy or magnetic field energy at the time of cavity resonance. It has come to be adopted.

Also, if an electromagnetic wave absorber mainly composed of a conductive material is mounted in a high frequency circuit package or used as a lid for a high frequency circuit package, the isolation of the amplifier mounted in the high frequency circuit package The characteristics were degraded. That is, the microwave propagating through the high-frequency transmission line formed on the package and a high frequency semiconductor device for high frequency circuit, a millimeter wave, since the current flows through the package lid, is unnecessary oscillations due to the feedback of the high-frequency signal Arise. In order to solve such a problem, there is a method in which an electromagnetic wave absorber having electrical insulation is disposed inside the lid of the high frequency circuit package to suppress the high frequency current flowing through the lid of the high frequency circuit package. It is taken.

  Electromagnetic wave absorbing materials disposed in such high-frequency circuit packages are broadly classified into magnetic materials, conductive materials, and dielectric materials. The principle that such an electromagnetic wave absorber absorbs electromagnetic wave energy will be described. When the electromagnetic wave energy incident on the radio wave absorber from the outside is converted into heat and the electromagnetic wave is absorbed as a result, the equation (1) is obtained, for example.

_{P = (1/2) ωμ 0 μ} r "| H | 2 + (1/2) ωε 0 ε r" | E | 2 ··· (1)
Where P: absorbed electromagnetic wave energy E: electric field H: magnetic field ω: electromagnetic wave angular frequency μ ₀ : vacuum permeability ε ₀ : vacuum permittivity μ _r ″: imaginary number of complex relative permeability of electromagnetic wave absorber Part ε _r ″: Imaginary part of complex relative permittivity of electromagnetic wave absorber From equation (1), if the imaginary part of complex relative permeability and complex relative dielectric constant is large, electromagnetic wave absorption energy is easily absorbed by the electromagnetic wave absorber. I understand. Further, when a material having a large imaginary part is used, the thickness of the electromagnetic wave absorbing layer can be reduced.

  The reason why the magnetic material absorbs electromagnetic waves in the high frequency region is considered to be that high frequency electromagnetic energy is converted into thermal energy by magnetic loss caused by the imaginary part of the complex relative permeability of the magnetic material. A part of the electromagnetic wave that has not been converted into thermal energy among the electromagnetic wave incident on the magnetic material passes through the magnetic material. In addition, the conductive material is a resistor that consumes electric energy when a voltage is applied, and consumes electrical energy. The reason why the resistor absorbs the high-frequency electromagnetic wave is considered to be that when an electric field is generated in the resistor, the electromagnetic wave energy is converted into thermal energy in the resistor. In order for the conductive material to efficiently absorb electromagnetic waves, it is generally necessary that the imaginary part of the complex relative dielectric constant is large. The dielectric material absorbs electromagnetic waves in the high frequency region because the dielectric loss of the dielectric material is converted into thermal energy. However, in general, a dielectric material has a property that it is difficult to absorb electromagnetic waves having a high frequency such as a GHz band. In order to absorb high frequency electromagnetic waves in the GHz band, a combination of a magnetic material and a dielectric material or / and a conductive material, or preferably a combination of a magnetic material and a conductive material is performed.

Further, as an electromagnetic wave absorber having excellent electromagnetic wave absorption characteristics in the MHz band, the electromagnetic wave absorber having a two-layer structure was stuck a metal plate is known which is a conductive material in a soft magnetic ferrite plate is a magnetic material. The two-layer structure, when the surface of the electromagnetic wave absorber is facing a gas such as air, was devised in order to reduce as much as possible the reflection of electromagnetic waves in the electromagnetic wave absorber surface. Conventionally, the characteristic impedance Z _c of the electromagnetic wave absorber when the reflection is zero between the electromagnetic wave absorber and gas, ideally there is a represented by the following formula.

Z _c = η (μ _r / ε _r ) ^1/2 (2)
Here, η: Characteristic impedance of gas such as air μ _r : Complex relative permeability ε _r : Complex relative permittivity However, in a high frequency region such as the GHz band, the conductive plate and the magnetic plate have a two-layer structure. only aligned with Z _c can not provide an electromagnetic wave absorber excellent in the electromagnetic wave absorption characteristics. The reason for this is thought to be that electromagnetic waves are likely to be reflected at the interface between the conductive plate and the magnetic plate because the wavelength is short in a high frequency region such as the GHz band.

Therefore, as an electromagnetic wave absorber disposed in the package for a high frequency circuit, first, in order to efficiently absorb the electromagnetic wave, the complex relative permittivity and the complex relative permeability in the operating frequency band are large. There has been a demand for an electromagnetic wave absorber that combines a material and a magnetic material and integrally forms both to suppress reflection of electromagnetic waves. In particular, with the recent increase in the frequency of high-frequency circuit packages, there has been a strong demand for the appearance of a radio wave absorber that absorbs high frequencies in the GHz band.

  For example, as an electromagnetic wave absorber attached to the inside of a high frequency circuit package, an electromagnetic wave absorber 72 (not suitable) made of a ferrite sheet or ferrite paint having a rectangular parallelepiped shape attached to the back surface of the package lid of the high frequency circuit package. (Patent Document 1).

  In addition, in order to improve electromagnetic wave absorption characteristics, an electromagnetic wave absorber produced by mixing and dispersing ferrite particles and conductive ceramic particles (Patent Document 2), and a crystal system having a spinel type or magnetoplumbite type composition. An electromagnetic wave absorber composite powder material (Patent Document 3) and the like made of a mixed powder obtained by mixing a ferrite magnetic powder and a ceramic powder in a weight ratio of 99.5: 0.5 to 90:10 are known.

Further, as shown in FIG. 12, Patent Document 4, a package base in which the high-frequency circuit board is mounted, the high-frequency circuit board and a dielectric disposed on the package base so as to seal on the package base a sealing substrate made of a material, the electromagnetic wave absorber disposed outside of the sealing substrate, and the high-frequency circuit package constituted by surrounding the electromagnetic wave absorber disposed conductive metal cap It is disclosed.

Patent Document 5 discloses a package base on which a high-frequency semiconductor element is mounted, a high-frequency transmission line formed on the high-frequency semiconductor element, a metal cap disposed on the package base, and an inner side of the metal cap. A high frequency circuit package comprising a disposed electromagnetic wave absorber and a high frequency circuit package in which a conductive metal film is attached to a part of the electromagnetic wave absorber on the high frequency transmission line side is disclosed.
JP-A-6-236935 JP-A-6-13780 JP 2002-289413 A JP 2000-138495 A Japanese Patent Laid-Open No. 2003-60101

However, ferrite sheet and ferrite paint to be mounted inside the package for high frequency circuits as disclosed in Patent Document 1 has a problem because flame retardance containing at least about 20% by weight of the synthetic resin is poor. In order to solve this problem, flame retardants such as decabromodiphenyl oxide, TBA epoxy oligomer / polymer, and TBA carbonate oligomer are added to the synthetic resin. Since such a flame retardant contains Br and Cl, desorption gas containing Br and Cl elements is generated when heated. When an electromagnetic wave absorber containing such a flame retardant is installed inside a high frequency circuit package, Br and Cl elements are removed by heating at the time of bonding of the package lid and the package base or bonding of the high frequency circuit package and the motherboard. The contained desorption gas fills the inside of the high-frequency circuit package 40. Since such desorbed gas is corrosive, there is a problem of corroding a semiconductor element (not shown) mounted inside a high frequency circuit package, a transmission line (not shown) formed on the package base, and the like. there were. In addition, ferrite sheets and ferrite paints containing synthetic resins generally have high porosity and are easy to permeate moisture and corrosive gases, so they cannot be used as lids for high-frequency circuit packages that require high reliability. .

In addition, the electromagnetic wave absorber disclosed in Patent Document 2 prepared by mixing and dispersing ferrite particles and conductive ceramic particles and then molding the electromagnetic wave absorption by the ferrite only at frequencies in the kHz to MHz band due to the limit of Snoek. The loss of electromagnetic wave energy due to the imaginary part of the complex relative dielectric constant of the conductive particles contained in the ferrite sintered body is reduced with an increase in frequency, so that absorption of electromagnetic waves at frequencies above the GHz band does not occur substantially. There was a problem that it was difficult. In addition, the electromagnetic wave absorber disclosed in Patent Document 2 is manufactured by mixing and dispersing ferrite particles and conductive ceramic particles, and forming them, so that the bonding between the particles is weak and the conductive particles and ceramic particles are peeled off. Then, it is discharged into the high-frequency circuit package, and the peeled particles come into contact with the high-frequency semiconductor element and the high-frequency circuit in the high-frequency circuit package, causing a malfunction of the high-frequency circuit package.

Further, in order to suppress the generation of desorbed gas, functional ceramics, for example, Ni - Zn ferrite also contemplated for use in the electromagnetic wave absorber but, Ni - F e ₂ O ₃ constituting the Zn ferrite is usually It was less than 50 mol% and could only be used for an electromagnetic wave absorber intended for a frequency band of about several MHz. In contrast, in recent years, there has been a demand for an electromagnetic wave absorber used in a high frequency band of 10 GHz or higher. However, even if such Ni — Zn ferrite is used for an electromagnetic wave absorber intended for a high frequency band of 10 GHz or higher, it is desirable. There was a problem that the electromagnetic wave absorption characteristics of the film could not be obtained.

  Further, with the advent of high-frequency circuit packages used in a high-frequency band of 10 GHz or more in recent years, the miniaturization of high-frequency circuit packages has become remarkable, and for high-frequency circuits used in a high-frequency band of 10 GHz or more. There is a need for an electromagnetic wave absorber that is mounted inside a package. The electromagnetic wave absorber disclosed in Patent Document 3 composed of a mixture of magnetic powder and ceramic powder has reduced electromagnetic wave absorption characteristics because ceramic particles that hardly absorb electromagnetic waves are dispersed in the magnetic powder for weight reduction. There was a problem. Further, the electromagnetic wave absorber described in Patent Document 3 has a problem that it is difficult to absorb an electromagnetic wave having a frequency of 1 GHz or more because the imaginary part of the complex permeability becomes small at a high frequency of about 1 GHz or more.

Moreover, the electromagnetic wave absorber disclosed in Patent Documents 2 and 3 transmits most of the electromagnetic waves. Therefore, the electromagnetic wave absorber disclosed in Patent Documents 2 and 3 when disposed in the package for high frequency circuit, a metal cap as unnecessary high frequency from the high frequency circuit is not oscillating package for high frequency circuits It was necessary to attach as a lid.

Moreover, in the high frequency circuit package of Patent Document 4, since it is necessary to attach both the electromagnetic wave absorber and the metal cap , it is difficult to reduce the size of the high frequency circuit package and the manufacturing cost is high. There was a problem.

  In the high frequency circuit package disclosed in Patent Document 5, a conductive metal film is bonded to a part of the main surface of the electromagnetic wave absorber, and then the electromagnetic wave absorber is placed inside the lid so that the metal film faces the high frequency transmission path. Therefore, there is a problem that the manufacturing cost becomes high.

Further, in the case of fixing by using a solder wave absorber in Patent Document 2 to 5 inside the package lid for high frequency circuits, those of the electromagnetic wave absorber 30 in order to increase the bonding strength between the lid and the electromagnetic wave absorber For example, a Cr layer, a Ni layer, and an Au layer were sequentially metallized on the contact surface, and then the electromagnetic wave absorber had to be joined. For this reason, there existed a problem that the joining cost to the cover body of an electromagnetic wave absorber became large.

Then, an object of this invention is to provide the electromagnetic wave absorber with a favorable electromagnetic wave absorption characteristic. In particular, an object of the present invention is to provide an electromagnetic wave absorber that exhibits good electromagnetic wave absorption characteristics in a high frequency band. In addition, the high-frequency circuit package can efficiently absorb unnecessary electromagnetic waves generated from the high-frequency circuit package, and the high-reliability electromagnetic wave absorber of the present invention in which fine particles do not fall into the high-frequency circuit package. An object of the present invention is to provide a package for a high-frequency circuit in which cavity resonance is suppressed and the isolation characteristic is good. Another object of the present invention is to provide a high frequency circuit package capable of firmly fixing the solder and the electromagnetic wave absorber at low cost when the electromagnetic wave absorber of the present invention is fixed to the high frequency circuit package lid with solder. . It is another object of the present invention to provide a high-frequency circuit package with good isolation characteristics especially for a high-frequency band of 10 GHz or more.

Electromagnetic wave absorber of the present invention, a ceramic sintered body having an insulating layer and a conducting layer, said insulating layer and said conductive layer comprises the same oxide magnetic material and are integrally sintered a volume resistivity at 25 ° C. to 100 ° C. is characterized ¹⁰ -2 ^{~10 3 Ω} · cm der Rukoto.

The electromagnetic wave absorber of the present invention comprises a ceramic sintered body having an insulating layer and a conductive layer, and the insulating layer and the conductive layer contain the same oxide magnetic material and are integrally sintered. The surface resistivity of the insulating layer at 25 ° C. to 100 ° C. is 10 ⁵ to 10 ¹⁴ Ω.

Further, the electromagnetic wave absorber of the present invention is the above-described structure, wherein the oxide magnetic material is at least one crystal phase selected from MnFe ₂ O ₄ , NiFe ₂ O ₄ , ZnFe ₂ O ₄ , or at least 2 of these. It contains a solid solution of seeds.

Moreover, the electromagnetic wave absorber of the present invention is characterized in that, in each of the above structures, the conductive layer contains Fe ₃ O ₄ .

  The high frequency circuit package of the present invention is characterized in that the electromagnetic wave absorber is disposed inside.

The high frequency circuit package of the present invention is characterized in that the electromagnetic wave absorber is used as a lid.

The high frequency circuit package of the present invention having the above structure, the high-frequency semiconductor element, and a circuit board for arranging the high-frequency semiconductor element, a package base for disposing the circuit board, the high-frequency semiconductor a high-frequency transmission line for transmitting a high frequency signal from the device is electrically connected to and the high-frequency semiconductor element, the package base and connected and the high-frequency semiconductor element, for housing the circuit board and the high-frequency transmission line ; and a lid, the package base and disposed the electromagnetic wave absorber on the inner surface of the cavity surrounded by the said lid, the high-frequency semiconductor element facing said electromagnetic wave absorber wherein the main surface conductive layer of the and then, characterized in that one side of the rear surface or the electromagnetic wave absorber of the main surface and said insulating layer.

The high frequency circuit package of the present invention having the above structure, the high-frequency semiconductor element, and a circuit board for arranging the high-frequency semiconductor element, a package base for disposing the circuit board, the high-frequency semiconductor a high-frequency transmission line for transmitting a high frequency signal from the device is electrically connected to and the high-frequency semiconductor element, the package base and connected and the high-frequency semiconductor element, for housing the circuit board and the high-frequency transmission line comprising a said lid, said lid is made of the electromagnetic wave absorber, wherein the main surface of the high-frequency semiconductor element opposite to the lid of the inner surface of the cavity enclosed by said package base and the lid a conductive layer, characterized in that one of the end faces or the outer peripheral surface of the lid and to the insulating layer.

The high frequency circuit package according to the present invention is characterized in that, in each of the above-described configurations, the transmission characteristics of the high frequency transmission line are substantially equal to the transmission characteristics when the package base is measured alone.

The high frequency circuit package of the present invention, each of the above structures, characterized in that the distance between the electromagnetic wave absorber and the high-frequency transmission line or more 0.1 mm.

The high frequency circuit package of the present invention is characterized in that the attenuation of electromagnetic waves in higher frequency 10GHz is using the electromagnetic wave absorber is more than 2dB.

  It is possible to provide an electromagnetic wave absorber excellent in electromagnetic wave absorption characteristics at high frequencies. In addition, it is possible to provide a package for a high-frequency circuit in which cavity resonance at high frequencies is suppressed and the isolation characteristics are excellent. This makes it possible to improve the quality of communication devices, computers, home appliances, and the like that are equipped with the high-frequency circuit package of the present invention. For example, high-quality data transmission / reception can be performed by mounting the high-frequency circuit package of the present invention on a mobile phone used in wireless communication.

  Hereinafter, the present invention will be described in detail with reference to the drawings.

As shown in FIG. 1, the electromagnetic wave absorber 30 of the present invention is a ceramic sintered body having a conductive layer 44 and the insulating layer 48, and the insulating layer 48 and the conductive layer 44 contain the same oxide magnetic material, and are integrally sintered, the volume resistivity at 25 to 100 ° C. is the ¹⁰ -2 ^{~10 3 Ω} · cm der Rukoto is important. Thus, the Tomo to be able to provide an electromagnetic wave absorber 30 having excellent electromagnetic wave absorption characteristics, it is possible to further suppress the cavity resonance in the above 10GHz high frequency circuit package 40. When the main surface 56 of the electromagnetic wave absorber 30 of the present invention is the conductive layer 44, it means that most of the main surface 56 is a conductive layer, and preferably 90% or more of the area of the main surface 56 is the conductive layer 44. And In the electromagnetic wave absorber 30 of FIG. 1A, the main surface 56 and the back surface of the main surface 56 include the conductive layer 44, and the end surface of the main surface 56 includes the insulating layer 48. Figure 1 the electromagnetic wave absorber 30 (b) is the major surface 56 is conductive layer 44, and the back and sides of the principal surface 56 is an insulating layer 48. The electromagnetic wave absorber 30 in FIG. 1C has a lid-like shape, and includes an insulating layer 48 on the outside and a conductive layer 44 on the inside.

  The electromagnetic wave absorber 30 is disposed inside the high frequency circuit package 40 as shown in FIGS. 2 and 3, or as the lid 52 of the high frequency circuit package 40 as shown in FIGS. Can be set up. Accordingly, it is possible to provide a package for a high-frequency circuit in which cavity resonance is suppressed and the isolation characteristics are excellent.

The volume resistivity at 25 to 100 ° C. of the electromagnetic wave absorber ^30, depending on the Dearuko 10 -2 ~10 ³ Ω · cm, it is possible to further suppress the cavity resonance in the above 10GHz high frequency circuit package 40 . This is because, when the volume resistivity is smaller than 10 ⁻² Ω · cm, the electromagnetic wave is easily reflected by the electromagnetic wave absorber 30, so that the electromagnetic wave absorption by the conductive material is remarkably lost. Further, when the volume resistivity is greater than 10 ³ Ω · cm, since conductivity of the electromagnetic wave absorber 30 is lowered, because the electromagnetic wave absorption by the conductive material is lost significantly less.

The electromagnetic wave absorber 30 of the present invention is made of a ceramic sintered body having an insulating layer 48 and a conductive layer 44, and the insulating layer 48 and the conductive layer 44 contain the same oxide magnetic material and are integrally formed. are sintered, the surface resistivity at 25 ° C. to 100 ° C. of the insulating layer 48 of the electromagnetic wave absorber 30 is thus in the 10 ⁵ to 10 ¹⁴ Omega der Turkey, further isolation characteristics of a high-frequency circuit package 40 Can be improved. This is because, when an amplifier is disposed in the high frequency circuit package 40, if an electromagnetic wave absorber having a surface resistivity smaller than 10 ⁵ Ω is disposed at the upper periphery of the amplifier, a high frequency signal is transmitted by the amplifier. This is because it is not preferable because it cannot be remarkably amplified, and it is not preferable because it is difficult to manufacture the electromagnetic wave absorber 30 having a surface resistivity larger than 10 ¹⁴ Ω.

The surface resistivity of the conductive layer 44 of the electromagnetic wave absorber 30 is preferably 10 ⁻⁴ to 10 ³ Ω · cm. Thereby, cavity resonance at 10 GHz or more of the high-frequency circuit package 40 can be further suppressed.

  The lower limit of the ratio of the thickness of the conductive layer 44 to the thickness of the main surface 56 of the electromagnetic wave absorber 30 is preferably 30%, and the upper limit is preferably 100%. The reason why the lower limit is set to 30% is that when 30% or more, the cavity resonance suppressing effect of the high-frequency circuit package 40 can be sufficiently exhibited.

The insulating layer 48 is preferably formed in a range of at least 0.5 mm in the depth direction from the surface to the inside of the electromagnetic wave absorber. This is because the electromagnetic wave absorber 30 having the insulating layer 48 formed in this range is disposed inside the high frequency circuit package 40 that operates at a frequency of 10 GHz or more, or is used as the lid 52 of the high frequency circuit package 40. In this case , the cavity resonance in the high frequency circuit package 40 can be particularly suppressed and the isolation characteristics can be improved.

In the boundary of the conductive layer 44 and the insulating layer 48, it is preferable that conductivity is inclined. That is, when the insulating layer 48 on the surface of the electromagnetic wave absorber 30 is polished little by little, the conductivity of the polished surface gradually decreases, and when the polishing allowance exceeds a certain value, the surface resistivity of the polished surface decreases and the conductivity becomes low. It becomes the surface which has.

The composition and crystal phase of the material of the electromagnetic wave absorber 30 of the present invention will be described. In order to suppress high-frequency cavity resonance in the high-frequency circuit package 40, the oxide magnetic material contained in the electromagnetic wave absorber 30 includes Ca, Mg, Sr, Ba, Cr, Mn, Fe, and the like as metal elements. It is preferable to contain at least one element selected from Co, Ni, Cu, Zn, Y, Ru, Rh, and a rare earth element. More _{preferably, MnMn 2 O 4, MnFe 2} O 4, MnCr 2 O 4, MnV 2 O 4, Mn 2 TiO4, MnRh 2 O 4, MnGeO 3, FeFe 2 O 4, FeCr 2 O 4, FeV 2 O 4 , Fe ₂ TiO ₄ , Fe ₂ GeO ₄ , FeCo ₂ O ₄ , FeTiO ₃ , CoCo ₂ O ₄ , CoFe ₂ O ₄ , CoCr ₂ O ₄ , Co ₂ GeO ₄ , Co ₂ TiO ₄ , CoRh ₂ O ₄ , CoMnO ₃ , CoTiO ₃ , NiMn ₂ O ₄ , NiMnO ₃ , NiFe ₂ O ₄ , NiCr ₂ O ₄ , NiCo ₂ O ₄ , NiGe ₂ O ₄ , NiRh ₂ O ₄ , NiTiO ₃ , CuMn ₂ O ₄ , CuFe ₂ O _{4 , CuCr 2 O 4, CuRh 2} O 4, CuRh 2 O 4, ZnMn 2 O 4, Z nCr ₂ O ₄ , ZnFe ₂ O ₄ , Zn ₂ TiO ₄ , ZnMnO ₃ , MgMn ₂ O ₄ , MgFe ₂ O ₄ , MgCr ₂ O ₄ , MgAl ₂ O ₄ , MgV ₂ O ₄ , Mg ₂ TiO ₄ , MgMnO ₃ , LiV ₂ O ₄ , BaFe ₁₂ O ₁₉ , BaFe ₁₈ O ₂₇ , BaZnFe ₁₇ O ₂₇ , BaZn _1.5 Fe _17.5 O ₂₇ , BaMnFe ₁₆ O ₂₇ , BaNi ₂ Fe ₁₆ O ₂₇ , BaNi _0.5 ZnFe _{16 .5 O 27, BaCo 0.75 Zn 0.75} Fe 16.5 O 27, Ba 2 Mg 2 Fe 12 O 22, Ba 2 Ni2Fe 12 O 22, Ba 2 Zn 2 Fe 12 O 22, Ba 2 Zn 1. _{5 Fe 12.5 O 22, Ba 2} Co 2 Fe 12 O 22, Ba 3 Co 2 Fe _{4 O 41, R 3 Fe 5} O 12 (R is a rare earth element), RFeO ₃ (R is a rare earth element) mainly containing at least one crystalline phase selected from. Particularly preferably, it contains at least one crystal phase selected from MnFe ₂ O ₄ , NiFe ₂ O ₄ , and ZnFe ₂ O ₄ , or at least two solid solutions thereof. Most preferably, it contains at least one of NiFe ₂ O ₄ and ZnFe ₂ O ₄ , or a solid solution thereof.

In order to suppress high-frequency cavity resonance in the high-frequency circuit package 40, the insulating layer 48 is made of FeFe ₂ O ₄ , FeCr ₂ O ₄ , FeCo ₂ O ₄ , CoCo ₂ O ₄ , CoFe ₂ O ₄ , CoCr. _{2 O 4, NiFe 2 O 4} , NiCr 2 O 4, NiCo 2 O 4, CuFe 2 O 4, CuCr 2 O 4, ZnCr 2 O 4, ZnFe 2 O 4, MgFe 2 O 4, MgCr 2 O 4, MnFe ₂ O ₄ , O, containing at least one crystal phase selected from CoO, and the conductive layer 44 is Cr ₂ O ₃ , MnO, Mn ₃ O ₄ , Co ₃ O ₄ , FeO, Fe ₃ O ₄ , ZnO, _{LaCrO 3, LaFeO 3, LaCrO 3} , LaCoO 3, LaNiO 3, LaSrZrO 3, FeAl 2 O 4, SrCrO 3, Sr uO _3, CaRuO _3, containing at least one crystalline phase selected from SrFeO _3. Particularly preferably, the insulating layer 48 contains at least one crystal phase selected from Fe ₂ O ₃ , NiO and CoO, and the conductive layer 44 is MnO, Mn ₃ O ₄ , Co ₃ O ₄ , FeO and Fe ₃ O. ₄ contains at least one crystal phase selected from ₄ ;

Most preferably, the conductive layer 44 and the insulating layer 48 both contain at least one of NiFe ₂ O ₄ and ZnFe ₂ O ₄ as a crystal phase, or a solid solution thereof, and Fe ₂ O ₃ as main components. Contains Fe ₃ O ₄ as a crystalline phase. Thus, it is possible to be generated by efficiently electromagnetic wave absorber both the dielectric loss and the magnetic loss, in particular a cavity resonance suppression can isolation characteristic obtain good high-frequency circuit package.

The crystal phase of a conductive layer 44 included in the electromagnetic wave absorber 30 and the insulating layer 48, X-ray diffraction method, be identified by a method or the like in combination with X-ray diffraction and transmission electron microscopy (TEM) I can .

Further, the electromagnetic wave absorber 30 preferably contains 70～95Mol% of Fe as the metal element in terms _{of Fe} 2 _{O 3.} Thereby, it is possible to improve electromagnetic wave absorption characteristics particularly in a high frequency band of 10 GHz or more. Further, since the NiFe ₂ O ₄ phase having a spinel structure is easier to be densified than the Fe ₂ O ₃ phase having a corundum structure, the oxide magnetism contained in the electromagnetic wave absorber disposed in the high-frequency circuit package 40 of the present invention. By using NiFe ₂ O _{4 as the} material, the high-frequency semiconductor element 26 , the high-frequency transmission line 22, and the like are not corroded by moisture or harmful gas that permeates from the outside to the inside of the high-frequency circuit package 40.

Further, in the present invention, in the case of using a metal as the material of the lid of a high-frequency circuit package 40, by precipitating the oxide magnetic material in the surface layer of the electromagnetic wave absorber 30 consisting of NiFe ₂ O ₄ phase, the electromagnetic wave absorption After only the Ni layer and the Au layer are sequentially metalized on the surface of the body 30, the electromagnetic wave absorber 30 and the lid of the high-frequency circuit package 40 can be brought into close contact with the solder. That is, this eliminates the need to provide a Cr layer on the surface of the electromagnetic wave absorber 30, thereby reducing the manufacturing cost.

  The electromagnetic wave absorber 30 of the present invention is produced by the following method, for example.

The case where the oxide magnetic material contained in the electromagnetic wave absorber 30 is NiFe ₂ O ₄ will be described. As a starting material, after the specific surface area was weighed powder ^2m 2 / g or more _Fe 2 _{O 3} and NiO, was prepared by introducing into a ball mill or bead mil with water, average particle size and 0.6~2μm to obtain a slurry and wet mixed and pulverized until. Further, in order to obtain a high-frequency circuit package 40 that suppresses cavity resonance further includes, ZnO, adding 2~10mol portion of at least one raw material powder of CuO to the total 100mol part of _Fe 2 _{O 3} and NiO It is preferable. After adding and mixing an organic binder to the obtained slurry, drying and granulating with a spray dryer, the obtained granulated powder is formed into a predetermined shape by a known molding means, for example, a powder pressure molding method. A molded body is obtained. Preferably, drying the slurries, to an average particle size of the resulting dried powder was calcined at about 700 to 900 ° C., water was added to the calcined powder obtained calcined powder is 2μm or less , was ground in a ball mill or a bead mill, after adding and mixing organic binder, granulated and dried again at a spray dryer, to obtain a resulting molding the granulated powder compact. Then, in an oxygen partial pressure of less than 0.15 atm atmosphere, after the molded body 0-10 hours baking at 1000 to 1400 ° C., further cooled at 300 to 500 ° C. / time, create manufactured electromagnetic wave absorber 30 To do. Here, when the powder pressure molding method is used, it is preferable to mold the molding pressure at, for example, 460 to 1900 MPa in order to produce a dense electromagnetic wave absorber 30 obtained by firing the molded body.

Further, in baked formation, it is important to bury only the surface to try to form an insulating layer 48 on the NiO powder. Thus, the surface of the electromagnetic wave absorber 30 which is fired by embedding the NiO powder to form a dielectric layer 48, making it possible to form a conductive layer 44 on the surface of the electromagnetic wave absorber obtained by firing without embedded NiO powder it can.

In particular, by the oxygen partial pressure in the baked formed is calcined in an atmosphere of 0.1 atm, control the volume resistivity at 25 ° C. to 100 ° C. of the electromagnetic wave absorber 30 in the range of ¹⁰ -2 to 10 ³ Omega The electromagnetic wave absorber 30 made can be produced. Further, by firing the firing temperature at 1250 ° C. to 1350 ° C., it can be obtained an electromagnetic wave absorber 30 having a controlled surface resistivity at 25 ° C. to 100 ° C. of the insulating layer 48 in the range of ¹⁰ 5 ^{to 10 14} Omega .

The electromagnetic wave absorber 30 when the oxide magnetic material contained in the electromagnetic wave absorber 30 is other than NiFe ₂ O ₄ is manufactured, for example, as follows . When oxides magnetic material is _{NiCr 2 O 4, NiCo 2 O} 4 can be prepared by replacing the _Fe 2 _{O 3} starting material to _Cr 2 _{O 3} or CoO. Further, when oxides magnetic material is _{CoFe 2 O 4, CuFe 2 O} 4, ZnFe 2 O 4 , respectively the powder for burying the NiO powder and the molded body of the starting material CoO, CuO, replaced with ZnO it can be produced.

Further, the electromagnetic wave absorber 30 is not limited to a substrate of a rectangular parallelepiped, a cylinder, a cone, triangular prism, a triangular pyramid, may have a shape consisting of a combination thereof.

As described above, the high-frequency circuit package 40 of the present invention has the electromagnetic wave absorber 30 disposed in the high-frequency circuit package 40. Preferably, the high-frequency circuit package 40 of the present invention is provided with a high-frequency semiconductor element 26, a circuit board 18 for arranging the high-frequency semiconductor element 26, and the circuit board 18 as shown in a sectional view in FIG. the package base 14 for a high-frequency transmission line 22 for transmitting a high-frequency semiconductor element 26 is electrically connected to and high-frequency semiconductor element 26 or al high-frequency signal, the package base 14 and connected and the high-frequency semiconductor element 26, ; and a lid for accommodating the circuit board 18 and the high-frequency transmission line 22, the electromagnetic wave absorber 30 is disposed on the inner surface of the cavity surrounded by the package base 14 and the lid 2 7, high-frequency semiconductor element 26 The main surface 56 of the electromagnetic wave absorber 30 facing the conductive layer 44 is the conductive layer 44, and either the back surface or the side surface of the main surface 56 is the insulating layer 48. Accordingly, it is possible to provide the high-frequency circuit package 40 in which cavity resonance is particularly suppressed in a frequency band higher than the GHz band. Preferably, a ground electrode is provided on the package base 14 as shown in FIG.

Since the electromagnetic wave absorber 30 consisting of a ceramic substrate which is disposed a high-frequency circuit package 40 of the present invention the conductive layer 44 and the insulating layer 48 is sintered integrally radiation absorbing and conductive material by a magnetic material It is possible to absorb electromagnetic waves simultaneously. Accordingly, or arranged both the electromagnetic wave absorber made of an electromagnetic wave absorber and the conductive material comprising a magnetic material as in the conventional high-frequency circuit package to the package for high frequency circuit, the conductive material and the insulating material the was dispersed mixture need not be or is disposed in the high-frequency circuit package an electromagnetic wave absorber after work made. Also, electricity when the lid 2 7 is made of a conductive material such as metal, by either the back or side of the main surface 56 and the insulating layer 48, and the electromagnetic wave absorber 30 and the lid 2 7 Therefore, the electromagnetic wave coupling between the electromagnetic wave absorber 30 and the high-frequency transmission line 22 can be suppressed, and the high-frequency circuit package 40 having excellent isolation characteristics can be obtained.

The high frequency circuit package 40 of the present invention uses the electromagnetic wave absorber 30 as the lid 52 as described above. Preferably, as shown in FIG. 4, the high-frequency semiconductor element 26, the circuit board 18 for arranging the high-frequency semiconductor element 26, the package base 14 for arranging the circuit board 18, and the high-frequency semiconductor element 26 And a high-frequency transmission line 22 for transmitting a high-frequency signal from the high-frequency semiconductor element 26, and for connecting the high-frequency semiconductor element 26, the circuit board 18, and the high-frequency transmission line 22 connected to the package base 14. Holders of Bei and a lid 52, made lid 52 from the electromagnetic wave absorber 30, and a main surface of the package base 14 and the cavity inner surface surrounded by the lid 52 high-frequency semiconductor element 26 facing the lid 52 Either the conductive layer 44 or the end surface or the outer peripheral surface of the lid 52 is used as the insulating layer 48. As a result, it is possible to provide the high frequency circuit package 40 in which the cavity resonance is particularly suppressed in the frequency band higher than the GHz band. More preferably, a ground electrode is provided on the package base 14 as shown in FIG. The end surface here is the surface where the package base 14 and the lid 52 in FIG. 4 and 5 are in contact.

Further, since the electromagnetic wave absorber 30 disposed in the high-frequency circuit package 40 in FIGS. 4, 5 and the conductive layer 44 and the insulating layer 48 is sintered integrally, electromagnetic wave absorption and conductivity due to the magnetic material material It is possible to absorb electromagnetic waves simultaneously. Since the lid 52 also serves as the electromagnetic wave absorber 30, there is no need to dispose the electromagnetic wave absorber in the high frequency circuit package unlike the conventional high frequency circuit package, and therefore the number of parts can be reduced and the high frequency circuit can be used. The package can be reduced in size and the manufacturing cost can be reduced. In addition, as shown in FIG. 6, a high-frequency circuit package 40 in which the package base 14 is a container and the lid is a substrate-like electromagnetic wave absorber 30 may be used.

The preferable form of each member which comprises the package for high frequency circuits of this invention is demonstrated. The high-frequency semiconductor element 26 is, for example, doped with any of impurities such as Si, Ge, Se, Te, GaAs, GaP, GaN, InSb, CdS, ZnTe, ZnO, for example, by a diffusion technique, and PN-junctioned . A source, a drain, and a gate are formed, and a high frequency signal of, for example, 100 MHz to 40 GHz is transmitted by applying a voltage. Package base 14 is made of ceramics, resin or the like. The high-frequency transmission line 22 is formed by, for example, forming a matching circuit, a distributed constant circuit, a passive circuit, a control circuit, an amplifier, a mixer, or a detection circuit on the circuit board 18, and specifically, for example, Au, Ag, Includes microstrip lines such as Cu, wire bonds, resistors, capacitors, and the like. Circuit board 18 is composed of ceramics, resins and the like. Lid 2 7 consists ceramics, metals, resins, etc., the cover 52 also serves as a electromagnetic wave absorber 30. High-frequency circuit package of the present invention, on the package base 14, distribution of the radio frequency transmission line 22 and the high-frequency semiconductor element 26 and circuit board 18 forming the after casting, and a lid and the package base 14 in a known manner, for example, Adhere by glass bonding and seal. Furthermore, to adhere to the inside of the lid 2 7 as shown in FIGS distribution after casting the electromagnetic wave absorber 30 is disposed, and a package base 14 and the lid 2 7. Also as described above, preferably provided with a ground layer on the inside and the lower surface of the package base 14 as shown in FIG.

Also shows the example of the high-frequency semiconductor element 26 disposed on the circuit board 18 radio frequency transmission line 22 in FIG. The high-frequency signal input from the electrode 13d on the input terminal side is composed of the high-frequency semiconductor element 26, the resistor 64, the capacitor 68, the negative electrode 13b, the positive electrode 13c, the metal wire 15 formed by wire bonding, and the MMIC (monolithic microwave IC). Then, the output signal is output as a high-frequency output signal from the electrode 13e on the output terminal side.

Further, the case where the high frequency circuit package 40 of the present invention is used as an apparatus for wireless communication at a carrier frequency f of wireless communication will be described as an example. For example, an input terminal (not shown) for inputting a baseband signal to the high-frequency semiconductor element 26 made of GaAs having a transmission / reception function, and an output terminal (not shown) for outputting a baseband signal from the high-frequency semiconductor element 26 , and a control terminal for electrically controlling the high-frequency semiconductor element 26 (not shown), provided the input terminal, output terminal, a control patronized terminal at the outer end of the high-frequency circuit package 40, the circuit high-frequency semiconductor element 26 is provided on the base plate 1 8, to electrically connect the high frequency transmission line 22 and these terminals. Input terminals, output terminals, the control patronized terminal, the low-frequency intermediate-wave signal than the carrier frequency f of the radio communications, the baseband signal, the power signal, a signal selected from the control signals to pass. High-frequency transmission line 22 is composed of a metal wire or the like for bonding is formed on the package base 14 a microstrip line, a high-frequency semiconductor element 26 and the microstrip trip line.

In the high-frequency circuit package 40 of the present invention, it is preferable that the transmission characteristics of the high-frequency transmission line 22 are substantially equal to the transmission characteristics when measured by the package base 14 alone. The package base 14 alone is a state in which the circuit board 18 is disposed on the package base 14, the ground electrode is disposed on the package base 14, and the lid bodies 2 7 and 52 and the electromagnetic wave absorber 30 are not disposed. . In this state, the object reflecting electromagnetic waves upwards rather name frequency transmission lines 22 because there is no attenuation of the cavity or signal indicates an ideal transmission characteristics. Transmission characteristics of the high-frequency transmission line 22 when the package base 14 itself is that of the power transmission coefficient when the 4-terminal circuit impedance is connected to a high frequency power source which is calibrated (S _21), a lid 2 7 electromagnetic wave absorber substrate 30 and the high-frequency circuit package 40 provided with or power transmission coefficient of the high frequency transmission line 22 when the high-frequency circuit package 40 provided with a lid 52 (S ₂₁₎ was measured in the same manner, both the difference in the _{S 21} is assumed substantially equal if 0.2dB or less. Preferably, the difference between the two S ₂₁ is 0.1 dB or less.

In the high frequency circuit package 40 of the present invention, the distance d ₁ between the high frequency transmission line 22 and the electromagnetic wave absorber 30 having the substrate shape or the lid body 52 and the high frequency transmission line 22 is preferably 0.1 mm or more. If the distance d ₁ between the electromagnetic wave absorber and the high-frequency transmission line 22 is less than 0.1 mm, it is not preferable because a signal flowing through the high-frequency transmission line is easily attenuated. Further, in the case of including an amplifier in the high frequency transmission line, in order to suppress the deterioration of the isolation characteristic in the peripheral amplifier, it is preferable that the upper limit of the distance d ₁ and 3 mm. The distance d ₁ means the shortest distance between the high-frequency transmission line 22 and the electromagnetic wave absorber substrate 30 or the shortest distance between the high-frequency transmission line 22 and the lid body 52, and the high-frequency circuit package 40 at a position where the shortest distance can be measured. cutting the measuring the _{d 1.}

  In addition, the high frequency circuit package 40 of the present invention uses the electromagnetic wave absorber 30 having an electromagnetic wave attenuation of 2 dB or more at a frequency of 10 GHz or more, thereby suppressing cavity resonance in the high frequency circuit package 40 and isolation. It is preferable for improving the characteristics. The electromagnetic wave absorber 30 whose attenuation of electromagnetic waves at a frequency of 10 GHz or more is 2 dB or more is preferably composed of the material of the electromagnetic wave absorber 30 described above.

In the case where the lid 52 of the high-frequency circuit package 40 is formed by an electromagnetic wave absorber 30 of the present invention, the porosity is a dense sintered body is not more than 2% of the package for high frequency circuit 40 airtightly It is preferable for improving the property.

Previously not a Figure 1 (a), (b) , was produced by the electromagnetic wave absorber 30 shown in (c) as follows.

As a starting material, each powder having a specific surface area of 2 to 3 m ² / g was weighed so as to have a composition with a molar ratio shown in Table 1, and mixed with water in a ball mill or bead mill to prepare an average particle size of 0.8. A slurry was obtained by wet-mixing and pulverizing to a thickness of ˜1.2 μm. The obtained slurry is dried, the obtained dried powder is calcined at about 700 to 900 ° C., and water is added to the obtained calcined powder until the average particle size of the calcined powder becomes 2 μm or less. After pulverizing with a ball mill or bead mill, an organic binder was added and mixed, dried and granulated with a spray dryer. The obtained granulated body was molded at a molding pressure of 460 to 1900 MPa to obtain a molded body having a predetermined shape. Then, in an atmosphere having an oxygen partial pressure shown in Table 1 (the remainder of oxygen is nitrogen), the obtained molded body was held at the firing temperature shown in Table 1 for 4 hours and then fired, and further 300 to 500 ° C / the temperature was lowered at the time, the electromagnetic wave absorber 30 formed of a sintered body was created made. Note that only the surface of the molded body on which the insulating layer 48 is to be formed on the electromagnetic wave absorber 30 was embedded in the embedding powder shown in Table 1 and fired.

The volume resistivity value and the surface resistivity at 25 ° C. of the obtained electromagnetic wave absorber 30 were measured using Loresta HP or Loresta FP manufactured by Mitsubishi Yuka Co. , Ltd. Moreover, the crystal phase of each surface was identified by the X-ray diffraction method or the micro X-ray diffraction method.

Next, it constituted the high-frequency semiconductor element 26 consisting of the high-frequency transmission line 22 and GaAs as shown in Fig. 7 on the circuit board 18 made of alumina. Further, Au-plated Kovar (KOV: Kovar is a registered trademark, hereinafter the same) the lid 2 7 made of steel prior to securing to the package base 14, in this cavity, Ni in the conductive layer 44 are sequentially plated Au layer the electromagnetic wave absorber 30 thickness of 0.2~2mm that (FIG. 1 (a), (b) ) were fixed by soldering to the inside of the metal lid body 2 7. The cavity in the high-frequency circuit package 40 has an outer diameter of 8 mm × 8 mm and a height of 0.2 to 6 mm. And a lid 2 7 and the package base 14 which is disposed an electromagnetic wave absorber 30 are joined by glass and to output a high frequency signal of 10GHz and 12GHz from the output terminal side of the electrodes 13e. In addition, to output a high frequency signal of 10GHz and 12GHz for the same output terminal side of the electrode 13e in place of the lid 2 7 which is arranged an electromagnetic wave absorber 30 with the lid 52 in FIG. 1 (c). As a result, no cavity resonance occurred in any of the high-frequency circuit packages 40.

Further, FIG. 1 (a), a lid 2 7 made of steel (b) the electromagnetic wave absorber 30 of the shape with Au plating (outer diameter 6 × 6 × 1mm) provided Kovar (KOV), a high frequency transmission line 22 a circuit board 18 provided with the microstrip line and the package base 14 is disposed on the package base 14 made of alumina ceramics superimposed as shown in FIG. 3 as the transmission characteristics of a high-frequency circuit package 40 of the package base alone Evaluated. The cavity in the high-frequency circuit package 40 has an outer diameter of 8 mm × 8 mm and a height of 0.2 to 6 mm. The electromagnetic wave absorber 30, prior to securing the lid 2 7 to the package base 14, in this cavity, the conductive layer 44 on the Ni, the electromagnetic wave absorber thickness were sequentially plated Au layer is 0.2 to 2 mm 30 It was soldered and fixed to the inside of the metal lid body 2 7. The transmission characteristics of the obtained high frequency circuit package are as follows. The power transmission coefficient S ₂₁ of the package base 14 alone, the high frequency transmission line 22, and the main surface of the electromagnetic wave absorber 30 in the frequency band of 100 MHz to 40 GHz using a network analyzer. S ₂₁ when the distance to 56 is set to 0 to 6 mm is measured, and if the difference ΔS _{21 (A)} between them is 0.1 dB or less, it is judged as good, and the others are judged as bad in transmission characteristics. X.

In addition, the electromagnetic wave attenuation in 10~40GHz of the electromagnetic wave absorber 30 was measured as follows. First, as shown in FIG. 8, the electromagnetic wave absorber 30 was placed on the package base 14 on which the transmission line 22 was formed so as to cover the transmission line 22. Here, the external dimensions of the package base 14 were set to 10 mm × 10 mm × 0.5 mm . Next, the probe 17 is pressed against the transmission line 22, and the power reflection coefficient S ₁₁ and the power transmission are transmitted in a frequency band of 10 to 40 GHz by a network analyzer (not shown) connected from the probe 17 via a coaxial cable (not shown). the coefficient _{S 21} was measured. Attenuation of the obtained electromagnetic wave by the mounting of the electromagnetic wave absorber 30, _{S 11} power reflection coefficient, when the power transmission coefficient and the _{S 21, | S 21 / (} 1-S 11) | was calculated by. Incidentally, the package base 14 itself of the power transmission coefficient _{S 21} of FIG. 8 was at least -1.5 dB.

As for the effect of suppressing the cavity resonance obtained by disposing the electromagnetic wave absorber 30 in the high frequency circuit package 40, as shown in FIG. 9, the package base 14 in which the transmission line 22 is formed, and the package base mounted on 14 were evaluated using a high-frequency circuit package 40 made of Au-plated Kovar (KOV) manufactured package lid 2 7 and having a cavity of 8mm × 8mm × 0.8mm. Power transmission coefficient S when the electromagnetic wave absorber 30 is attached at 10 to 40 GHz by a network analyzer (not shown) connected to the high-frequency transmission line 22 through the probe 17 via a coaxial cable (not shown). _21, the absolute value of the difference between the power transmission coefficient S ₂₁ when not wearing the electromagnetic wave absorber 30 △ S _{21 (B)} is less than 0.1dB as what was the effect of cavity resonance suppression ○ , ΔS _{21 (B)} was 0.1 dB or more, and x was regarded as having no effect of suppressing cavity resonance.

Further, a lid 52 made of an electromagnetic wave absorber 30 in the form of FIG. 1 (c) (outer diameter 10 × 10 mm), the package comprising a circuit board 18 provided with the microstrip line as high-frequency transmission line 22 of alumina ceramics The package base 14 disposed on the base 14 was overlapped as shown in FIG. 4 to evaluate the transmission characteristics of the high-frequency circuit package 40 using the package base alone. A power transmission coefficient S ₂₁ of the package base 14 alone, by measuring the S ₂₁ of the high-frequency circuit package 40 when disposed the lid 52, to evaluate [Delta] S ₂₁ a _(A) from the difference between the two, as well if [Delta] S _{21 (a)} is at 0.1dB or less as ○ and judged to be good, and as × determines the others and transmission characteristics is poor. Also, the effect of cavity resonance suppressing the high-frequency circuit package 40 includes a package base 14 high-frequency transmission line 22 is formed, a lid member 52 made of electromagnetic wave absorber 30 mounted on the package base 14 It was evaluated using the package for high frequency circuit 40. Pressing the probe 17 to the high frequency transmission line 22, the power transmission coefficient S ₂₁ when mounting the lid 52 in 10~40GHz by a network analyzer that is connected via a coaxial cable from the probe 17, not fitted with a lid 52 When the absolute value ΔS _{21 (B)} of the difference from the power transmission coefficient S ₂₁ is less than 0.1 dB, the case where the effect of suppressing the cavity resonance is obtained is evaluated as ○, and ΔS _{21 (B)} is 0. .Times.1 dB or more was marked as x because there was no effect of suppressing cavity resonance.

These results are shown in Table 1 and FIG. As is apparent from Table 1, sample Nos. Within the scope of the present invention. 1-No. In No. 14, ΔS _{21 (A)} was 0.1 dB or less at 100 MHz to 40 GHz, the transmission characteristics of the high-frequency transmission line 22 were good, and no cavity resonance occurred.

Also, for example, sample No. As shown in FIG. 10B, S ₂₁ of 100 MHz to 40 GHz of 1 was obtained with transmission characteristics (FIG. 10A) of the package base 14 alone and S ₂₁ within 0.1 dB . Sample No. 4 is the distance between the electromagnetic wave absorber 30 and the high-frequency transmission line 22 is in close proximity and very less than 0.1 mm, _{S 21} at 40GHz is - 1.8 dB, and the Sample No. Compared with 1 to 3 and 5 to 14, the transmission characteristics (isolation) of the high-frequency transmission line 22 could not be remarkably improved.

Sample No. No. of JCPDS from the electromagnetic wave absorber 30 of the insulating layer 48 and the conductive layer 44 using the 1,2 The X-ray diffraction method revealed that 10-0325 NiFe ₂ O ₄ phase was contained, and that the conductive layer 44 further contained Fe ₃ O ₄ phase.

On the other hand, sample no. For 15 to 18, ΔS _{21 (A)} is larger than 0.1 dB and the transmission characteristics of the high-frequency transmission line are deteriorated, or ΔS _{21 ( B)} is 0.1 dB or more and the effect of suppressing cavity resonance is obtained. I did not. Further, as shown in FIG. 11A, the sample No. in which the electromagnetic wave absorber was not provided was arranged. 15, a large cavity resonance peak occurred in the vicinity of 26 GHz. In addition, as shown in FIGS. _{S 21} of 16, 18, _{S 21} becomes abruptly smaller as the frequency becomes higher, the transmission characteristic worsens.

The composition shown in Table 1 is, for example, sample No. In the case of 1, the molar ratio of Fe ₂ O ₃ and NiO is 0.9: indicates a 0.1. Further, it was confirmed by ICP emission spectroscopic analysis that the composition of each electromagnetic wave absorber was the same between the starting material and after firing. In Table 1, sample No. D ₁ of 15 indicates the distance between the lid and the high-frequency transmission line.

(A)-(c) is sectional drawing of the electromagnetic wave absorber arrange | positioned at the package for high frequency circuits of this invention. It is sectional drawing of the package for high frequency circuits of this invention. It is sectional drawing of the package for high frequency circuits of this invention. It is sectional drawing of the package for high frequency circuits of this invention. It is sectional drawing of the package for high frequency circuits of this invention. It is sectional drawing of the package for high frequency circuits of this invention. It is the circuit board and high frequency transmission line which are arrange | positioned at the package for high frequency circuits of this invention. It is sectional drawing of the apparatus which measures the attenuation amount of the electromagnetic wave obtained by mounting | wearing with the electromagnetic wave absorber arrange | positioned at the package for high frequency circuits of this invention. It is sectional drawing for evaluating the cavity resonance suppression of the package for high frequency circuits of this invention. (A), (b) is a graph showing the _{S 21} of a high-frequency circuit package of Example. (A) ~ (c) is a graph showing the _{S 21} of a high-frequency circuit package of the comparative example. It is sectional drawing of the conventional high frequency circuit package.

13: Electrode 13a: Ground electrode 13b: Negative electrode 13c: Positive electrode 13d: Input terminal side electrode 13e: Output terminal side electrode 14, 73: Package base 15: Wire 17: Probe 18: Circuit board 20: Attenuation of electromagnetic wave Measuring device 22: High-frequency transmission line
26: High-frequency semiconductor element 2 7 , 52, 71: Lid 30, 72: Electromagnetic wave absorber 40, 70: Package for high-frequency circuit 56: Main surface 60: MMIC
64: Resistor 68: Capacitor 74: High frequency circuit board 75: Dielectric substrate 76: Metal wall

Claims (11)

A ceramic sintered body having an insulating layer and a conducting layer, said insulating layer and said conductive layer comprises the same oxide magnetic material and are integrally sintered, the volume at 25 ° C. to 100 ° C. electromagnetic wave absorber resistivity and wherein ¹⁰ -2 ^{~10 3 Ω} · cm der Rukoto. It consists of a ceramic sintered body having an insulating layer and a conductive layer, and the insulating layer and the conductive layer contain the same oxide magnetic material and are integrally sintered. electrostatic surface resistivity at 100 ° C. is it being a ¹⁰ 5 ^{to 10 14} Omega wave absorber. The oxide magnetic material contains at least one crystal phase selected from MnFe ₂ O ₄ , NiFe ₂ O ₄ , and ZnFe ₂ O ₄ , or at least two solid solutions thereof. Or the electromagnetic wave absorber of 2. Electromagnetic wave absorber according to any one of claims 1 to 3, wherein the conductive layer is characterized by containing Fe ₃ O _4. A package for a high-frequency circuit, wherein the electromagnetic wave absorber according to any one of claims 1 to 4 is disposed therein. A package for a high-frequency circuit, wherein the electromagnetic wave absorber according to any one of claims 1 to 4 is used as a lid. A high-frequency semiconductor element, the circuit board for high-frequency semiconductor element is disposed, and the package base for disposing the circuit board, wherein the high-frequency semiconductor element electrically connected and the high frequency from the high-frequency semiconductor element a high-frequency transmission line for transmitting a signal, the package base and connected and the high-frequency semiconductor device, said circuit comprising: a lid body for housing the substrate and the high-frequency transmission line, said package base and said lid and disposing the electromagnetic wave absorber on the inner surface of the cavity surrounded by the main surface of the electromagnetic wave absorber opposed to the high-frequency semiconductor element and the conductive layer, the side of the rear surface or the electromagnetic wave absorber of the primary surface 6. The high frequency circuit package according to claim 5 , wherein any one of the insulating layers is used. A high-frequency semiconductor element, the circuit board for high-frequency semiconductor element is disposed, and the package base for disposing the circuit board, wherein the high-frequency semiconductor element electrically connected and the high frequency from the high-frequency semiconductor element a high-frequency transmission line for transmitting a signal, the package base and connected and the high-frequency semiconductor device, comprising the said lid for accommodating the circuit board and the high-frequency transmission line, the electromagnetic wave absorption lid member made from the body, said package base and the main surface of the high-frequency semiconductor element opposite to the lid of the inner surface of the cavity enclosed by said cover body and said conductive layer, either end face or the outer circumferential surface of the lid The high-frequency circuit package according to claim 6 , wherein the insulating layer is used. The high-frequency transmission characteristics of the transmission line, a high-frequency circuit package according to claim 7 or 8, wherein the transmission characteristics and substantially equal when measured with the package base alone. The high frequency circuit package according to any one of claims 7 to 9 , wherein a distance between the electromagnetic wave absorber and the high frequency transmission line is 0.1 mm or more. The package for a high frequency circuit according to any one of claims 5 to 10 , wherein the electromagnetic wave absorber having an electromagnetic wave attenuation amount of 2 dB or more at a frequency of 10 GHz or more is used.

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