JP2005203723A - Glass ceramic substrate and method for manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a glass ceramic substrate provided with a ferrite layer having high magnetic permeability and having constitution in which the inductance of a coil conductor built in the ferrite layer is high and stable, and to provide a method for manufacturing the glass ceramic substrate. <P>SOLUTION: The ferrite layer 2 baked simultaneously with glass ceramic insulating layers 6 by microwaves including a coil conductor buried in its inside and having the same size as the glass ceramic insulating layers 6 are formed on the inner layer of an insulating substrate 1. A plurality of glass ceramic insulating layers 6 are laminated on the substrate 1 through an intervention layer comprising at least one sort of an insulating layer 4 and a baked metallic layer 5, having thickness of ≥10μm and formed between the glass ceramic insulating layers 6 and the ferrite layer 2. The thermal expansion coefficient of the ferrite layer 2 is higher than that of glass and filler of the glass ceramic insulating layer 6, the insulating layer 4 contains glass having a thermal expansion coefficient higher than that of the glass ceramic insulating layer 6 and the same ferrite as that of the ferrite layer 2 and the baked metallic layer 5 contains prescribed metal and glass. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention provides a ferrite layer for increasing an inductance value, which is formed by firing together with a glass ceramic insulating layer and having a coil conductor embedded therein, in an insulating base made of a glass ceramic sintered body. The obtained glass ceramic substrate.

  2. Description of the Related Art Conventionally, many electronic devices are incorporated in electronic devices such as mobile communication devices such as mobile phones. Such communication devices such as mobile phones have been rapidly reduced in size in recent years, and various electronic devices mounted thereon are required to be reduced in size and thickness. For example, an LC filter having a configuration in which a coil is built in a glass ceramic substrate is known. In the case of this LC filter, there is an advantage that it is possible to reduce the size and thickness by incorporating the coil of the conventional chip component inside the glass ceramic substrate.

  However, in a glass ceramic substrate having a built-in coil, it is difficult to incorporate a coil exceeding 100 nH because the coil is formed in a non-magnetic glass ceramic substrate. Therefore, in recent years, it is possible to incorporate a coil exceeding 100 nH by incorporating a ferrite layer in the glass ceramic substrate, thereby simplifying the surface mounting process and reducing the size of the glass ceramic substrate. In these methods, the ferrite layer and the glass ceramic insulating layer are simultaneously fired in order to form a ferrite layer inside the glass ceramic substrate.

  On the other hand, when firing these glass-ceramic substrates, a microwave as shown in Patent Document 3 has recently been used in place of electric furnace firing, because the firing time can be shortened and the energy efficiency can be improved as compared with electric furnace firing. Firing is drawing attention.

In the microwave firing, while the electric furnace firing is heated and fired from the surface to the inside of the object by heat transfer from the outside, the object to be fired is self-heated by the irradiated microwave. Since the product can be efficiently heated and a temperature gradient is hardly generated on the surface and inside of the object to be fired, the timing of firing on the surface and inside of the object to be fired can be made substantially the same. Microwave firing having such characteristics is an electric furnace because, for example, a dielectric layer having a high dielectric constant can be selectively sintered in firing a wiring substrate having a dielectric layer inside. Since the sinterability of the dielectric portion is deteriorated in the firing, use is being studied for improving the sinterability.
JP-A-6-20839 JP-A-6-21264 Japanese Patent Laid-Open No. 10-149941

  In the conventional configuration, in the simultaneous firing of the ferrite layer and the glass ceramic insulating layer, the thermal expansion coefficient of the ferrite layer and the thermal expansion coefficient of the glass ceramic insulating layer are different, so stress is applied to the ferrite layer during the simultaneous firing process. There has been a problem that magnetostriction occurs and the permeability of the ferrite layer rapidly decreases.

  Further, when the ferrite layer is formed thick in order to prevent the magnetic permeability from being lowered, there is a problem that the sintered ferrite layer is easily peeled off. This is because the shrinkage and thermal expansion coefficient during firing differ between the ferrite layer and the glass ceramic insulating layer. If a large amount of ferrite layer is formed, the occurrence of peeling becomes significant. Therefore, in order to adhere the ferrite layer and the glass ceramic insulating layer by co-firing and to match the respective thermal expansion coefficients, glass powder or glass ceramic powder has to be added to the ferrite layer.

  However, since the glass powder and glass ceramic powder added to the ferrite layer are non-magnetic, they form a non-magnetic space in the ferrite layer, and the density of ferrite in the ferrite layer is reduced. There was a problem.

  In general, the magnetic properties of a magnetic material such as ferrite are expressed using magnetic permeability (μ) as an index. The higher the magnetic permeability, the higher the coil inductance. However, the magnetic permeability decreases in proportion to the cube of the volume of the nonmagnetic portion when a nonmagnetic portion exists in the magnetic material. Therefore, when glass powder or glass ceramic powder is added to the ferrite layer as described above, there has been a problem that the permeability of the ferrite layer is drastically lowered and the inductance of the coil is lowered.

  Furthermore, in any of the above-described methods for forming a ferrite layer, there is a problem that it is difficult to form the thickness of the ferrite layer uniformly with good reproducibility. Usually, the ferrite layer is formed on the glass ceramic green sheet by screen printing a ferrite paste. However, in this method, the ferrite layer of the glass ceramic substrate produced in the same manner and the same glass ceramic substrate are used. There is a problem that the thickness varies even between different ferrite layers. Further, if a ferrite layer having a thin thickness is formed locally, the coil inductance cannot be sufficiently obtained in that portion. Therefore, in order to avoid this, it is necessary to increase the thickness of the ferrite layer more than necessary. However, forming the ferrite layer thickly has a problem that the peeling during firing is promoted as described above.

  For the reasons described above, the ferrite layer inside the insulating substrate can only be formed with a small volume or low density, and there is also a variation in coil inductance between glass ceramic substrates produced in the same way. There is a problem that it is difficult to stably obtain a glass ceramic substrate having sufficient coil characteristics.

  In addition, when a ferrite layer is formed by simultaneous firing with an insulating substrate and a wiring conductor composed of a plurality of glass ceramic insulating layers, if an attempt is made to fire the ferrite layer at a higher density in order to increase the magnetic permeability, However, there is a problem that there is a limit to the densification of ferrite.

  The present invention has been made in view of the problems in the conventional technology as described above, and an object thereof is to provide a ferrite layer having a high magnetic permeability, and the inductance of the coil conductor incorporated in the ferrite layer is reduced. An object of the present invention is to provide a glass ceramic substrate that is high and stable and a method for manufacturing the same.

  The glass-ceramic substrate of the present invention is formed on the inner layer of an insulating substrate formed by laminating a plurality of glass-ceramic insulating layers made of glass and filler, and is simultaneously fired with the glass-ceramic insulating layer, and a coil conductor is formed therein. An embedded ferrite layer having the same size as the glass ceramic insulating layer is interposed between the glass ceramic insulating layer and an intervening layer having a thickness of at least one of an insulating layer and a sintered metal layer of 10 μm or more. The ferrite layer has a higher thermal expansion coefficient than the glass and filler of the glass ceramic insulating layer, and the insulating layer has a thermal expansion coefficient higher than that of the glass ceramic insulating layer. Containing the same ferrite as the ferrite contained in the high glass and the ferrite layer, Sintered metal layer are those wherein Cu, Ag, Au, Pt, that contains at least one metal and glass of the Ag-Pd alloy and Ag-Pt alloy.

In the glass ceramic substrate of the present invention, preferably, the ferrite is ZnFe ₂ O ₄ , MnFe ₂ O ₄ , FeFe ₂ O ₄ , CoFe ₂ O ₄ , NiFe ₂ O ₄ , BaFe ₁₂ O ₄ , SrFe _12. O ₄ and CuFe of ₂ O ₄ in that it consists of at least one in which the features.

  In the glass ceramic substrate of the present invention, preferably, the firing shrinkage start temperature and the firing shrinkage end temperature of the glass ceramic insulating layer are T1 and T2, respectively, and the firing shrinkage start temperature and the firing shrinkage end of the ferrite layer. When the temperatures are T3 and T4, respectively, T3 <T1 and T2 <T4.

  In the glass ceramic substrate of the present invention, the glass contained in the glass ceramic insulating layer is preferably T5 and T6, respectively, with the softening temperature and the crystallization temperature of the glass contained in the insulating layer being set as described above. T5 <T8 and T7 <T6, where T7 is T7 and the sintering start temperature of the ferrite layer is T8.

The manufacturing method of the glass ceramic substrate of the present invention is a manufacturing method of the glass ceramic substrate of the present invention, and includes a plurality of glass ceramic green sheets, ZnFe ₂ O ₄ , MnFe ₂ O ₄ , FeFe ₂ O ₄ , CoFe. _A coil conductor is disposed between the glass ceramic green sheets having the same size as at least one of ₂ O ₄ , NiFe ₂ O ₄ , BaFe ₁₂ O ₄ , SrFe ₁₂ O ₄ and CuFe ₂ O _4. And an insulating paste layer containing the same calcined powder as the ferrite contained in the glass having a higher thermal expansion coefficient than the glass ceramic insulating layer and the ferrite contained in the ferrite layer, and Cu, Ag. , Au, Pt, Ag—Pd alloy and Ag—Pt alloy Laminating through at least one metal paste layer containing at least one metal powder and glass powder, and producing a glass ceramic green sheet laminate having the uppermost layer and the lowermost layer as the glass ceramic green sheet; ,
And a step of firing after removing the organic component from the glass ceramic green sheet laminate.

A method for manufacturing a glass ceramic substrate of the present invention is a method for manufacturing a glass ceramic substrate of the present invention, a plurality of glass ceramic green _{sheets, ZnFe 2 O 4, MnFe 2} O 4, FeFe 2 O 4 , CoFe ₂ O ₄ , NiFe ₂ O ₄ , BaFe ₁₂ O ₄ , SrFe ₁₂ O _4, and CuFe ₂ O ₄ , the same size as the glass ceramic green sheet, and a coil conductor An insulating paste layer containing a glass having a higher thermal expansion coefficient than the glass ceramic insulating layer and a ferrite calcined powder same as the ferrite contained in the ferrite layer, and Cu , Ag, Au, Pt, Ag—Pd alloy and Ag—Pt alloy Laminating via at least one metal powder layer containing at least one metal powder and a glass powder, and producing a glass ceramic green sheet laminate having the uppermost layer and the lowermost layer as the glass ceramic green sheet; ,
Laminating a constrained green sheet containing a non-sinterable inorganic material, glass and an organic binder on both upper and lower surfaces of the glass ceramic green sheet laminate;
Producing a glass ceramic substrate holding the restraint sheet by firing after removing organic components from the laminate of the restraint green sheet and the glass ceramic green sheet laminate;
Removing the constraining sheet from the glass ceramic substrate,
The glass content of the constraining green sheet is an amount that binds the constraining green sheet with the glass ceramic green sheet during the firing and does not substantially shrink the constraining green sheet in the laminated surface. Is.

  The method for producing a glass ceramic substrate of the present invention is the method for producing a glass ceramic substrate, wherein the glass ceramic green sheet laminate or the laminate of the constrained green sheet and the glass ceramic green sheet laminate is microwave-absorbed. And by irradiating the glass ceramic green sheet laminate or the laminate of the constrained green sheet and the glass ceramic green sheet laminate with microwaves through the housing, It is characterized by firing.

  According to the glass ceramic substrate of the present invention, since a glass component that forms a space having no magnetism is not contained in the ferrite layer, a decrease in the magnetic permeability of the ferrite layer can be suppressed. Further, an insulating layer containing the same ferrite as the ferrite contained in the glass and ferrite layer having a higher thermal expansion coefficient than the glass ceramic insulating layer, and Cu, Ag, Au, Pt, Ag—Pd alloy and Ag—Pt alloy. Since an intervening layer having a thickness of 10 μm or more of at least one of the sintered metal layers containing at least one metal and glass is interposed between the ferrite layer and the glass ceramic insulating layer, the glass Thermal expansion difference between the ferrite layer and the glass ceramic insulating layer due to the insulating layer and the sintered metal layer having a thermal expansion coefficient larger than that of the ceramic insulating layer and smaller than that of the ferrite layer The stress caused by the above can be relaxed, and the decrease in the permeability of the ferrite layer due to magnetostriction can be suppressed.

  Further, since the ferrite layer and the intervening layer composed of at least one of the insulating layer and the sintered metal layer are formed by simultaneous firing of the glass ceramic insulating layer and the wiring conductor, the ferrite layer, the intervening layer, and the glass Sufficient adhesion between the ceramic insulating layer and the wiring conductor can be obtained. In addition, a ferrite layer of the same size as the glass ceramic insulating layer is formed by sintering a ferrite green sheet, and the coil conductor is embedded inside, so that the inductance of the coil conductor by the ferrite layer is highly stable. And can be held.

  In addition, since the glass ceramic substrate is made by laminating two types of glass ceramic insulation layers and ferrite layers with different firing shrinkage behavior, the glass ceramic insulation layer and the ferrite layer suppress the mutual shrinkage in a certain firing temperature range. Thus, it also has an effect of sintering while suppressing thermal stress.

According to the glass ceramic substrate of the present invention, the ferrite forming the ferrite layer is ZnFe ₂ O ₄ , MnFe ₂ O ₄ , FeFe ₂ O ₄ , CoFe ₂ O ₄ , NiFe ₂ O ₄ , BaFe ₁₂ O ₄ , SrFe _12. When composed of at least one of O ₄ and CuFe ₂ O ₄ , the crystal phase of these ferrites exhibits a high magnetic permeability, and therefore, the inductance of the coil conductor is more effectively achieved by the ferrite layer composed of these ferrites. It is possible to obtain a sufficiently high magnetic permeability that can increase the resistance.

  Further, according to the glass ceramic substrate of the present invention, the firing shrinkage start temperature and the firing shrinkage end temperature of the glass ceramic insulating layer are T1 and T2, respectively, and the firing shrinkage start temperature and the firing shrinkage end temperature of the ferrite layer are T3 and T4, respectively. When T3 <T1 and T2 <T4, since the firing shrinkage start temperature T3 of the ferrite green sheet is lower than the firing shrinkage start temperature T1 of the glass ceramic green sheet, the ferrite green sheet is made of glass ceramic. The glass ceramic green sheet is in an unsintered state because its firing shrinkage start temperature T1 is higher than the firing shrinkage start temperature T3 of the ferrite green sheet, although it tries to shrink by sintering before the green sheet. There will be little shrinkage. Therefore, in a laminate in which a ferrite green sheet and a glass ceramic green sheet are laminated in close contact, the ferrite green sheet shrinks in the thickness direction, but in a direction perpendicular to the thickness direction, i.e., on the lamination surface. Even if it is going to shrink in the parallel direction, the movement is restricted by the glass ceramic green sheet, so that the shrinkage hardly occurs.

  In addition, since the firing shrink end temperature T4 of the ferrite green sheet is higher than the firing shrink end temperature T2 of the glass ceramic green sheet, the movement of the ferrite green sheet is restricted by the already sintered glass ceramic green sheet. The shrinkage hardly occurs in the direction parallel to the laminated surface, and the shrinkage occurs only in the thickness direction. Therefore, the shrinkage due to the firing of the laminate is mainly in the thickness direction, and the shrinkage hardly occurs in the direction parallel to the laminated surface. As a result, it is possible to suppress the occurrence of defective interlayer connection and displacement of the electrode pattern.

  Further, according to the glass ceramic substrate of the present development, the softening temperature and the crystallization temperature of the glass contained in the insulating layer are T5 and T6, respectively, and the softening temperature of the glass contained in the glass ceramic insulating layer is T7, When the sintering start temperature of the ferrite layer is T8, when T5 <T8 and T7 <T6, the softening temperature T5 of the glass contained in the insulating layer is higher than the sintering start temperature T8 of the ferrite green sheet. Because the glass is low, the glass contained in the insulating layer diffuses into the ferrite layer sooner than the ferrite layer starts to sinter and promotes the sintering of the ferrite layer as a liquid phase, so the interface between the insulating layer and the ferrite layer is strong. A bonding interface can be formed. Furthermore, since the crystallization temperature T6 of the glass contained in the insulating layer is higher than the softening temperature T7 of the glass contained in the glass ceramic insulating layer, the glass contained in the bonding layer diffused into the glass ceramic insulating layer is Since it exists as a liquid phase at the same time as the glass contained in the glass ceramic insulating layer, it has good wettability with each other and promotes the sintering of the glass ceramic insulating layer to form a strong bonding interface at the interface between the insulating layer and the glass ceramic insulating layer. can do.

The manufacturing method of the glass ceramic substrate of the present invention is a manufacturing method of the glass ceramic substrate of the present invention, and includes a plurality of glass ceramic green sheets, ZnFe ₂ O ₄ , MnFe ₂ O ₄ , FeFe ₂ O ₄ , CoFe. _{2 O 4, NiFe 2 O 4} , including _BaFe 12 _{O 4,} at least one of the _SrFe 12 _{O 4} and CuFe ₂ O _4, the same size as the glass ceramic green sheets were arranged coil conductors between At least two ferrite green sheets, an insulating paste layer containing the same ferrite calcined powder as the ferrite contained in the glass and ferrite layer having a higher thermal expansion coefficient than the glass ceramic insulating layer, and Cu, Ag, Au, At least one of Pt, Ag—Pd alloy and Ag—Pt alloy A step of producing a glass ceramic green sheet laminate in which the uppermost layer and the lowermost layer are laminated through at least one of metal paste layers containing a genus powder and a glass powder, and the uppermost layer and the lowermost layer are glass ceramic green sheets; Since it has a step of firing after removing the organic component from the laminate, it is possible to obtain a glass ceramic substrate in which a ferrite layer composed of ferrite that expresses high magnetic permeability is suppressed and a decrease in magnetic permeability is suppressed, A glass ceramic substrate having a built-in coil conductor having higher inductance can be obtained by the ferrite layer made of these ferrites.

  In addition, a glass ceramic green sheet laminate in which the shrinkage in the direction parallel to the laminated surface that occurs during firing of the glass ceramic substrate can be suppressed, and the ferrite layer can be prevented from being deformed, and a ferrite layer having different thermal shrinkage is formed during firing. The plurality of glass ceramic insulating layers, the wiring conductors, and the ferrite layers in the insulating base can be fired simultaneously without deforming.

  Furthermore, according to the method for producing a glass ceramic substrate of the present invention, the glass content of the constrained green sheet including each of the above steps and laminated on both surfaces of the glass ceramic green sheet laminate is obtained by converting the constrained green sheet into a glass ceramic during firing. Since the amount is such that it is bonded to the green sheet and the constrained green sheet does not substantially contract in the laminated surface, the constrained green sheet does not substantially contract in the direction parallel to the laminated surface generated during firing. In addition, it is possible to suppress the shrinkage in the direction parallel to the laminated surface, which occurs during the firing of the glass ceramic substrate, and to prevent the deformation of the ferrite layer.

  Further, according to the method for producing a glass ceramic substrate of the present invention, a glass ceramic green sheet laminate or a laminate of a constrained green sheet and a glass ceramic green sheet laminate is surrounded by a microwave-absorbing casing, and the casing Self-heating of the microwave because the organic component was removed and baked by irradiating microwaves to the glass ceramic green sheet laminate or the laminate of the constrained green sheet and the glass ceramic green sheet laminate through the body Due to the effect, the ferrite layer having a higher dielectric constant and higher microwave absorption than the glass ceramic green sheet or constrained green sheet is preferentially sintered. As a result, it becomes possible to sinter the ferrite layer to a higher density, and it is possible to obtain a glass ceramic substrate in which a ferrite layer composed of ferrite that exhibits high magnetic permeability is suppressed from decreasing in magnetic permeability. . Therefore, it is possible to obtain a glass ceramic substrate in which a coil conductor having higher inductance is built in by a ferrite layer made of these ferrites. Furthermore, if the thickness of the glass ceramic substrate is increased, the effect of self-heating by the microwave becomes more remarkable.

  In addition, the object to be fired is self-heated by surrounding the object to be fired with a microwave-absorbing housing, irradiating the material to be fired with microwaves through the housing, removing organic components, and firing. Since the dependency on heating is reduced and it is difficult to be restricted by the product capacity during firing, the firing capacity can be increased.

  As described above, according to the present invention, it is possible to provide a glass ceramic substrate that includes a ferrite layer having a high magnetic permeability, has a high and stable inductance of the coil conductor, and a method for manufacturing the same.

  The present invention will be described in detail below with reference to the accompanying drawings. FIG. 1 is a cross-sectional view showing an example of an embodiment of a glass ceramic substrate of the present invention, wherein 1 is an insulating base composed of a plurality of glass ceramic insulating layers 6, 2 is a ferrite layer, and 3 is a wiring conductor including a coil conductor. 4 is an insulating layer, 5 is a sintered metal layer, and 6 is a glass ceramic insulating layer. FIG. 2 (a) shows an example of an embodiment of the method for producing a ceramic multilayer wiring board of the present invention, and is a plan view of a microwave firing furnace used in the method for producing a ceramic multilayer wiring board of the present invention. FIG. 2B is a cross-sectional view taken along line A-A ′ in FIG. 2A, and FIG. 2C is a cross-sectional view taken along line B-B ′ in FIG. 2A to 2C, 7 is an object to be fired, 8 is a microwave-absorbing housing, 9 is a microwave firing furnace, 10 is a furnace wall, 11 is a heat insulating wall, 12 is a microwave absorbing wall, 13 is a microwave-absorbing shelf board, 14 is a pedestal, 15 is a firing atmosphere gas supply nozzle, 16 is a firing atmosphere gas, and 17 is an opening.

  The insulating substrate 1 of the present invention is configured by laminating a plurality of glass ceramic insulating layers 6, and a ferrite layer 2 in which a wiring conductor 3 is embedded in an inner layer thereof is interposed via an insulating layer 4 and a sintered metal layer 5. Is formed.

The insulating substrate 1 is made of a glass ceramic green sheet to be a glass ceramic insulating layer 6 and a ferrite green sheet to be a ferrite layer 2, and a conductive paste to be a wiring conductor 3 and an insulating layer to the glass ceramic green sheet and the ferrite green sheet. After printing the insulating paste to be 4 and the sintered metal paste to be the sintered metal layer 5, a plurality of these glass ceramic green sheets and ferrite green sheets are laminated,
It is produced by firing at a temperature of 800 to 1100 ° C. in the air or in a humidified nitrogen atmosphere.

  The glass ceramic insulating layer 6 is obtained by first mixing glass powder and filler powder (ceramic powder), and further mixing an organic binder, plasticizer, organic solvent, etc. to obtain a slurry, from which a doctor blade method, a rolling method, a calender roll method, etc. Thus, a glass ceramic green sheet to be the glass ceramic insulating layer 6 is manufactured, and the ferrite layer 2 is sandwiched between a plurality of glass ceramic green sheets.

Examples of the glass powder include SiO ₂ —B ₂ O ₃ , SiO ₂ —B ₂ O ₃ —Al ₂ O ₃ , SiO ₂ —B ₂ O ₃ —Al ₂ O ₃ —MO (where M is Ca , Sr, Mg, Ba or Zn), SiO ₂ —Al ₂ O ₃ —M ¹ O—M ² O system (where M ¹ and M ² are the same or different, and Ca, Sr, Mg, Ba or Zn) _{shown), SiO 2 -B 2 O 3} -Al 2 O 3 -M 1 O-M 2 O system (where, ^{M 1} and ^{M 2} are the same as _{above), SiO 2 -B 2 O 3} -M ³ ₂ O system (where M ³ represents Li, Na or K), SiO ₂ —B ₂ O ₃ —Al ₂ O ₃ —M ³ ₂ O system (where M ³ is the same as above), Pb glass or Bi glass can be used.

Examples of the filler powder include Al ₂ O ₃ , SiO ₂ , a composite oxide of ZrO ₂ and an alkaline earth metal oxide, a composite oxide of TiO ₂ and an alkaline earth metal oxide, and Al ₂ O. A composite oxide (for example, spinel, mullite, cordierite) containing at least one selected from ₃ and SiO ₂ can be used.

  The wiring conductor 3 is formed on the surface and inside of the insulating substrate 1 and inside the ferrite layer 2, and is prepared by kneading a suitable organic binder and solvent into metal powder such as Cu, Ag, Au, and Ag alloy. The conductive paste is applied to the glass ceramic green sheet surface and the ferrite green sheet surface by a screen printing method, a gravure printing method, or the like, and fired simultaneously with the glass ceramic green sheet and the ferrite green sheet.

  The insulating layer 4 is formed between the ferrite layer 2 covering the upper and lower surfaces of the wiring conductor 3 and the glass ceramic insulating layer 6. The insulating layer 4 is made of glass powder and ferrite layer 2 having a higher thermal expansion coefficient than the glass ceramic insulating layer 6. The ferrite layer 2 on the glass ceramic green sheet is placed on an insulating paste prepared by blending the contained ferrite powder and kneading an appropriate organic binder and solvent by a conventionally known screen printing method or gravure printing method. The glass ceramic green sheet is fired simultaneously with the glass ceramic green sheet.

In addition, the ferrite powder of the insulating layer 4 is the same as the ferrite powder of the ferrite layer 2, and ZnFe ₂ O ₄ , MnFe ₂ O ₄ , FeFe ₂ O ₄ , CoFe ₂ O ₄ , NiFe ₂ O ₄ , BaFe ₁₂ O _4. , SrFe ₁₂ O ₄ , CuFe ₂ O _4, or the like can be used.

The glass powder of the insulating layer 4 may be the same as the glass ceramic of the glass ceramic insulating layer 6, for example, _SiO 2 _-B 2 _{O 3 based, SiO 2 -B 2 O 3 -Al} 2 O 3 System, SiO ₂ —B ₂ O ₃ —Al ₂ O ₃ —MO system (where M represents Ca, Sr, Mg, Ba or Zn), SiO ₂ —Al ₂ O ₃ —M ¹ O—M ² O System (provided that M ¹ and M ² are the same or different and represent Ca, Sr, Mg, Ba or Zn), SiO ₂ —B ₂ O ₃ —Al ₂ O ₃ —M ¹ O—M ² O system (provided that , M ¹ and M ² are the same as described above), SiO ₂ —B ₂ O ₃ —M ³ ₂ O system (where M ³ represents Li, Na or K), SiO ₂ —B ₂ O ₃ — Al ₂ O ₃ -M ³ ₂ O system (where M ³ is the same as above) Pb glass, Bi glass, etc. can be used.

  Furthermore, if the glass contained in the insulating layer 4 has a softening temperature lower than the sintering start temperature of the ferrite layer 2 and a crystallization temperature higher than the softening temperature of the glass contained in the glass ceramic insulating layer 6, ferrite is used. Since the glass contained in the insulating layer diffuses into the ferrite layer earlier than the layer starts sintering and promotes the sintering of the ferrite layer as a liquid phase, a strong joint interface is formed at the interface between the insulating layer and the ferrite layer. In addition, since the glass contained in the bonding layer diffused in the glass ceramic insulating layer exists as a liquid phase at the same time as the glass contained in the glass ceramic insulating layer, each glass ceramic insulating layer has good wettability and can be sintered. This is desirable because it promotes and forms a strong bonding interface at the interface between the insulating layer and the glass ceramic insulating layer.

  The insulating layer 4 as an intervening layer is formed with a thickness of 10 μm or more. If the thickness is less than 10 μm, the stress relaxation is insufficient, and magnetostriction is generated, so that the magnetic permeability tends to decrease. However, the thickness of the insulating layer 4 is preferably such that it does not increase the thickness of the entire glass ceramic substrate, for example, 50 μm or less.

  The sintered metal layer 5 as an intervening layer is formed between the ferrite layer 2 covering the upper and lower surfaces of the wiring conductor 3 and the glass ceramic insulating layer 6, and includes Cu, Ag, Au, Pt, Ag—Pd alloy and A metal paste prepared by blending a glass powder with a metal powder of at least one metal of an Ag-Pt alloy and kneading an appropriate organic binder and solvent is obtained by a conventionally known screen printing method or gravure printing method. It is formed by applying the ferrite layer 2 on the glass ceramic green sheet at a position where it is placed and firing it at the same time as the glass ceramic green sheet.

The glass powder of the sintered metal layer 5 may be the same as the glass ceramic of the glass ceramic insulating layer 6, for example, _SiO 2 _-B 2 _{O 3 based, SiO 2 -B 2 O 3 -Al} 2 O ₃ system, SiO ₂ —B ₂ O ₃ —Al ₂ O ₃ —MO system (where M represents Ca, Sr, Mg, Ba or Zn), SiO ₂ —Al ₂ O ₃ —M ¹ O—M ² O system (provided that M ¹ and M ² are the same or different and represent Ca, Sr, Mg, Ba or Zn), SiO ₂ —B ₂ O ₃ —Al ₂ O ₃ —M ¹ O—M ² O system (However, M ¹ and M ² are the same as above.), SiO ₂ —B ₂ O ₃ —M ³ ₂ O system (where M ³ represents Li, Na or K), SiO ₂ —B ₂ O _3- Al ₂ O ₃ -M ³ ₂ O system (where M ³ is the same as above) Pb glass, Bi glass, etc. can be used.

  The sintered metal layer 5 may have the same composition as the wiring conductor 3, and a part of the wiring conductor 3 may be used as the sintered metal layer 5.

  The sintered metal layer 5 is formed with a thickness of 10 μm or more. When the thickness is less than 10 μm, stress relaxation is insufficient and magnetostriction is generated, so that the permeability of the ferrite layer 2 is likely to be lowered. However, the thickness of the sintered metal layer 5 is preferably such that it does not thicken the entire glass ceramic substrate, for example, 50 μm or less.

The ferrite layer 2 is formed together with the wiring conductor 3 on the inner layer of the insulating base 1 so as to cover the upper and lower surfaces of the wiring conductor 3. The ferrite layer 2 includes at least one of ZnFe ₂ O ₄ , MnFe ₂ O ₄ , FeFe ₂ O ₄ , CoFe ₂ O ₄ , NiFe ₂ O ₄ , BaFe ₁₂ O ₄ , SrFe ₁₂ O ₄ and CuFe ₂ O _4. Use of one type of ferrite is preferable in that a sufficiently high magnetic permeability can be obtained.

  The ferrite layer 2 is formed by first mixing a ferrite powder with a suitable organic binder, plasticizer, organic solvent, etc. to obtain a slurry, and then producing a ferrite green sheet by a doctor blade method, a rolling method, a calender roll method, or the like. . Next, the ferrite green sheet is cut into the same shape as the glass ceramic green sheet in plan view so as to cover the predetermined wiring conductor 3, and the wiring conductor 3 is interposed in the glass ceramic green sheet laminate. The conductor pattern is arranged and laminated so as to cover the upper and lower surfaces of the wiring conductor 3.

  At this time, in order to effectively increase the inductance of the coil conductor, it is necessary to completely cover the upper and lower surfaces of the wiring conductor 3 with the ferrite layer 2. Therefore, in order to form such a wiring conductor 3 and a ferrite layer 2, a pattern of a ferrite green sheet to be the lower ferrite layer 2, a conductor paste to be the wiring conductor 3, on the surface of a predetermined glass ceramic green sheet, Each layer may be arranged and laminated in the order of the ferrite green sheet to be the upper ferrite layer 2.

  The ferrite powder used for forming the ferrite green sheet to be the ferrite layer 2 is a calcined ferrite powder, and preferably has a uniform particle size and a nearly spherical shape. This is because a uniform sintered state can be obtained. For example, in the case where a ferrite powder has a small particle size, the growth of crystal grains is reduced only in that portion. There is a tendency that the magnetic permeability of the ferrite layer 2 is difficult to stabilize.

  In the method for producing a glass ceramic substrate of the present invention, first, a ferrite layer 2 and a wiring conductor 3 are laminated together with a plurality of glass ceramic green sheets as described above to produce a glass ceramic green sheet laminate.

  And after removing an organic component from this glass ceramic green sheet laminated body, it bakes. The organic component is preferably removed by heating the glass ceramic green sheet laminate in a temperature range of 100 to 800 ° C. while applying a load to the glass ceramic green sheet laminate to decompose and volatilize the organic component. Moreover, although a firing temperature changes with glass-ceramic compositions, it is in the range of about 800-1100 degreeC normally. Firing is usually performed in the air, but when Cu is used as the conductor material of the wiring conductor 3, organic components are removed in a humidified nitrogen atmosphere at 100 to 700 ° C., and then the firing is performed in a nitrogen atmosphere.

  Further, at the time of removing the organic component and at the time of firing, in order to prevent the glass ceramic green sheet laminate from warping, it is preferable to apply a load by placing a weight on the upper surface thereof. The load due to such weight is suitably about 50 Pa to 1 MPa. When the load is less than 50 Pa, the effect of suppressing the warp of the glass ceramic green sheet laminate tends to be insufficient. In addition, when the load exceeds 1 MPa, the weight to be used becomes large, so that it cannot enter the firing furnace, or even if it enters the firing furnace, the weight is so large that the heat capacity is insufficient and firing cannot be performed. There is a risk of causing problems.

  This weight is a heat-resistant porous material that does not deform or melt during the firing of the glass-ceramic substrate, resulting in non-uniform loads or hindering the volatilization of decomposed organic components. Are suitable. Specifically, a refractory material such as ceramics or a high melting point metal can be used. Further, a porous weight may be placed on the upper surface of the glass ceramic green sheet laminate, and a non-porous weight may be placed thereon.

  Further, in the method of manufacturing a glass ceramic substrate using a constrained green sheet, first, the ferrite layer 2 and the wiring conductor 3 are laminated together with a plurality of glass ceramic green sheets as described above, and the uppermost layer and the lowermost layer are made of glass. A glass ceramic green sheet laminate is produced as a ceramic green sheet.

  Next, a constrained green sheet containing a hardly sinterable inorganic material, glass and an organic binder is laminated on the upper and lower surfaces of the glass ceramic green sheet laminate.

  An organic component is removed from the laminate of the constrained green sheet and the glass ceramic green sheet laminate, and then fired to produce a glass ceramic substrate holding the constrained sheet. Finally, the constrained sheet is removed from the glass ceramic substrate. Remove.

The constrained green sheet in the present invention is obtained by molding a slurry in which an organic binder, a plasticizer, a solvent, and the like are added to an inorganic component composed of a hardly sinterable inorganic material and glass. Examples of the hardly sinterable inorganic material include at least one selected from Al ₂ O ₃ and SiO _2, but are not limited thereto.

  The glass added to the constraining green sheet is not particularly limited, and the same glass as that used for the glass ceramic green sheet can be used. Further, the glass in the constrained green sheet may have the same composition as that of the glass in the glass ceramic green sheet, or may have a different composition.

  The glass content in the constrained green sheet is preferably 0.5 to 15% by weight of the total inorganic components in the constrained green sheet. This range is an amount that binds to the glass ceramic green sheet at the time of firing and does not substantially shrink the constrained green sheet within the laminated surface, but is not necessarily limited to this range, depending on the type of glass used, etc. The glass content varies.

  The softening point of the glass in the constrained green sheet is preferably lower than the firing temperature of the glass ceramic green sheet laminate and higher than the decomposition temperature and volatilization temperature of the organic component in the constrained green sheet. Specifically, the softening point of the glass in the constrained green sheet is preferably about 450 to 1100 ° C. When the glass softening point is less than 450 ° C., the removal of the organic component from the glass ceramic green sheet will block the removal path of the decomposed and volatilized organic component, and the organic component is completely removed. May not be removed. On the other hand, when the softening point of the glass exceeds 1100 ° C., there is a possibility that it does not act as a binder to the glass ceramic green sheet under the normal firing conditions of the glass ceramic green sheet.

  The constrained green sheet is obtained by molding using an organic binder, a plasticizer, a solvent, and the like in the same manner as the production of the glass ceramic green sheet. As an organic binder, a plasticizer, and a solvent, the same material as that used in the glass ceramic green sheet can be used. Here, the reason why the plasticizer is added is to impart flexibility to the constraining green sheet and to enhance the adhesion to the glass ceramic green sheet during lamination.

  The thickness of the constrained green sheet laminated on both surfaces of the glass ceramic green sheet laminate is preferably 10% or more with respect to the thickness of the glass ceramic green sheet laminate on one side only. There is a possibility that the restraint property of the green sheet is lowered. In addition, when the volatilization of the organic component is facilitated and the removal of the restraint sheet from the glass ceramic substrate is taken into consideration, the thickness of the restraint green sheet is preferably about 200% or less of the thickness of the glass ceramic green sheet laminate. Further, the constrained green sheets to be laminated may be composed of a single sheet, or may be a laminate of a plurality of sheets so as to have a predetermined thickness.

  In order to laminate the formed constrained green sheets on both sides of the glass ceramic green sheet laminate, heat and pressure are applied to the stacked green sheets by thermocompression bonding, or an adhesive comprising an organic binder, plasticizer, solvent, etc. The method of apply | coating between sheets and carrying out thermocompression bonding etc. is employable. When an adhesive layer is interposed between the green sheets, this adhesive layer may contain the same glass component as that of the constraining green sheet to increase the bonding force between the green sheets.

  After stacking the constrained green sheets, the organic components are removed and fired. The removal of the organic component is performed by heating the laminate in a temperature range of 100 to 800 ° C. while applying a load to the laminate to decompose and volatilize the organic component. Moreover, although a calcination temperature changes with glass ceramic compositions, it exists in the range of about 800-1100 degreeC. Firing is performed in the air. When Cu is used as the conductor material, the organic components are removed in a humidified nitrogen atmosphere at 100 to 700 ° C., and then the firing is performed in a nitrogen atmosphere.

  Further, at the time of removing the organic component and at the time of firing, a load may be applied by placing a weight on the upper surface of the laminated body in order to prevent warping of the laminated body. The load due to such weight is suitably about 50 Pa to 1 MPa. When the load is less than 50 Pa, there is a possibility that the effect of suppressing the warpage of the laminate is not sufficient. In addition, when the load exceeds 1 MPa, the weight to be used becomes large, so that it cannot enter the firing furnace, or even if it enters the firing furnace, the weight is so large that the heat capacity is insufficient and firing cannot be performed. There is a risk of causing problems.

  As this weight, there is a heat-resistant porous material that does not deform or melt during firing of the glass ceramic substrate to make the load non-uniform or to prevent volatilization of decomposed organic components. Are suitable. Specifically, a refractory material such as ceramics or a high melting point metal can be used. Further, a porous weight may be placed on the upper surface of the laminate, and a non-porous weight may be placed thereon.

  After firing, the constraining sheet is removed. The removal method is not particularly limited as long as the constraining sheet bonded to the surface of the glass ceramic substrate can be removed. For example, ultrasonic cleaning, polishing, water jet, chemical blasting, sand blasting, wet blasting (with abrasive grains and water) And the like).

  In the obtained glass ceramic substrate, the shrinkage during firing is suppressed only in the thickness direction by the constraining green sheet, so that the shrinkage in the laminated surface can be suppressed to about 0.5% or less. Since the glass ceramic green sheet is uniformly and reliably bonded over the entire surface by the restraining green sheet, it is possible to effectively prevent the warp and deformation of the glass ceramic substrate due to partial peeling of the restraining green sheet. it can.

  In addition, in the method for manufacturing a glass ceramic substrate in which organic components are removed and fired by irradiating with microwaves, the object to be fired is placed in a microwave-absorbing casing 8 as shown in FIG. The organic component is removed and baked by arranging and irradiating the object 7 to be baked with microwaves through the casing 8. Densification of the obtained glass ceramic substrate is promoted by the self-heating effect of microwaves.

  Further, in the method for manufacturing a glass ceramic substrate of the present invention, the object to be fired 7 is surrounded by a microwave-absorbing casing 8. Since the object to be fired 7 is surrounded by the microwave-absorbing housing 8, the housing 8 itself also self-heats, and heat dissipation from the material to be fired 7 can be prevented. At this time, the microwave absorptivity of the housing 8 is preferably the same as or higher than that of the ferrite layer 2. In this case, heat dissipation from the ferrite layer 2 is reduced, the heat balance in the housing 8 becomes uniform, the ferrite layer 2 becomes dense, and it is possible to effectively prevent warping and deformation of the glass ceramic substrate. it can. On the other hand, when the microwave absorbability of the casing 8 is lower than the microwave absorbability of the ferrite layer 2, the temperature difference between the casing 8 and the ferrite layer 2 becomes large, and heat dissipation from the ferrite layer 2 cannot be prevented. As a result, the density of the ferrite layer 2 may be lowered or the glass ceramic substrate may be warped.

  In Example 1, a test piece for evaluation having a ring shape having an outer diameter of 20 mm and an inner diameter of 5 mm as shown in the cross-sectional view of FIG. 3 was prepared, and the magnetic permeability was measured. In FIG. 3, the same reference numerals are assigned to the same parts as in FIG. 1, 2 is a ferrite layer, 4 is an insulating layer, and 6 is a glass ceramic insulating layer. The permeability was measured using an impedance analyzer “HP-4291A” (manufactured by Hewlett Packard) by the high frequency current voltage method.

First, as a glass ceramic component, SiO ₂ —Al ₂ O ₃ —MgO—B ₂ O ₃ —ZnO glass powder 60% by weight, CaZrO ₃ powder 20% by weight, SrTiO ₃ powder 17% by weight, and Al ₂ O ₃ powder 3 % By weight was used. To 100 parts by weight of the glass ceramic component, 12 parts by weight of an acrylic resin as an organic binder, 6 parts by weight of a phthalic acid plasticizer, and 30 parts by weight of toluene as a solvent were added and mixed by a ball mill method to form a slurry. Using this slurry, a glass ceramic green sheet having a thickness of 300 μm was formed by a doctor blade method.

Next, as a ferrite green sheet, calcined with a magnetic permeability of 150.0 composed of crystal phases of ZnFe ₂ O ₄ , MnFe ₂ O ₄ , FeFe ₂ O ₄ , and NiFe ₂ O _{4 having} an average particle diameter of 0.5 to 1 μm. To the finished ferrite powder, 10% by weight of butyral resin and 45% by weight of high molecular weight alcohol were added as a diluent and mixed by a ball mill method to obtain a slurry. Using this slurry, a ferrite green sheet having a thickness of 80 μm was formed by a doctor blade method.

Next, the same SiO ₂ —Al ₂ O ₃ —MgO—B ₂ O ₃ —ZnO glass powder as the glass powder contained in the glass ceramic as the insulating paste, 30% by mass, the ferrite powder contained in the ferrite green sheet green sheet 70% by mass of ferrite powder composed of a crystal phase of ZnFe ₂ O ₄ , MnFe ₂ O ₄ , FeFe ₂ O ₄ , NiFe ₂ O ₄ having the same average particle diameter of 0.5 to 1 μm, and a predetermined amount of ethyl cellulose Resin and terpineol were added and mixed by three rolls so as to obtain an appropriate viscosity.

  The glass ceramic green sheet, the ferrite green sheet, and the constrained green sheet were both processed into a ring shape having an outer diameter of 20 mm and an inner diameter of 5 mm, which is a test piece shape for permeability evaluation.

  First, a predetermined number of glass ceramic green sheets were overlapped, and an insulating paste layer was applied over the entire surface and dried. The insulating paste layer was 20 μm thick. Thereafter, a ferrite green sheet was superposed on the dried insulating paste layer, and further, the insulating paste layer was applied over the entire surface and dried. The insulating paste layer was 20 μm thick. Thereafter, a predetermined number of glass ceramic green sheets were superposed on the dried insulating paste layer and pressure-bonded at a temperature of 55 ° C. and a pressure of 20 MPa to obtain a glass ceramic laminate.

  The obtained glass ceramic laminate was placed on an alumina ceramic setter, and a weight composed of the same components as the alumina ceramic setter was placed on the glass ceramic laminate, and a load of about 0.5 MPa was applied at 500 ° C. in the atmosphere. After removing the organic components by heating for 2 hours, it was fired at 900 ° C. for 1 hour in the air.

  Although the obtained glass ceramic substrate had the ferrite layer 2 formed on the entire inner layer, the glass ceramic substrate was not warped or deformed.

  Moreover, the thickness after baking of the insulating layer 4 of the obtained glass ceramic substrate was 10 micrometers.

  Table 1 shows the results of measuring the overall shrinkage, shrinkage variation, and magnetic permeability of the glass ceramic substrate of Example 1 obtained in this way.

Instead of the insulating layer 4 of Example 1, 80% by mass of Ag powder (average particle size 1.0 μm) and 20% by mass of SiO ₂ —Al ₂ O ₃ —MgO—B ₂ O ₃ —ZnO-based glass powder were used. A test piece for evaluation of Example 2 was produced in the same manner as Example 1 except that the binder metal layer 5 was formed. Table 1 shows the results of measuring the overall shrinkage, shrinkage variation, and magnetic permeability of the obtained glass ceramic substrate.

A glass ceramic laminate was produced by the same production method as in Example 1, and a constrained green sheet was superposed on each of the upper and lower surfaces of the glass ceramic laminate, and the laminate was crimped at a temperature of 55 ° C. and a pressure of 20 MPa. Obtained. The restraint green sheet uses 95% by mass of Al ₂ O ₃ powder as an inorganic component and 5% by mass of SiO ₂ —Al ₂ O ₃ —MgO—B ₂ O ₃ —ZnO-based glass powder having a softening point of 720 ° C. A slurry was prepared in the same manner as the glass ceramic green sheet of Example 1, and then molded to a thickness of 250 μm.

  The obtained laminate is placed on an alumina setter, and a weight of alumina ceramic is applied to the laminate so as to cover the top surface of the laminate, and a load of 0.5 MPa is applied to the laminate. The organic component was removed by heating at 500 ° C. for 2 hours in the air, and then baked at 900 ° C. for 1 hour in the air. After firing, constraining sheets were attached to both surfaces of the glass ceramic substrate. In this state, the restraint sheet did not peel off even when tapped lightly.

Most of the constraining sheet attached to the surface of the glass ceramic substrate could be removed by rubbing, but it remained thin on the surface of the glass ceramic substrate. The remaining constraining sheet was removed by a wet blasting method in which a mixture of spherical Al ₂ O ₃ fine powder and water was projected with high pressure air pressure. The surface of the glass ceramic substrate after removing the constraining sheet was a smooth surface having an arithmetic average roughness Ra of 1 μm or less. Table 1 shows the results of measuring the overall shrinkage, shrinkage variation, and magnetic permeability of the obtained glass ceramic substrate.

(Comparative Example 1)
A test piece for evaluation of Comparative Example 1 was produced in the same manner as in Example 1 except that the insulating layer 4 was produced so that the thickness after firing was 5 μm. Table 1 shows the results of measuring the overall shrinkage, shrinkage variation, and magnetic permeability of the obtained glass ceramic substrate.

(Comparative Example 2)
A substrate for evaluation consisting of only the ferrite layer 2 was prepared without stacking the glass ceramic insulating layer 6 with respect to Example 1. Table 1 shows the results of measuring the overall shrinkage, shrinkage variation, and magnetic permeability of the obtained glass ceramic substrate.

Measurement of the shrinkage and shrinkage variation of the evaluation substrates of Examples 1 to 3 and Comparative Examples 1 and 2 produced as described above were performed by measuring the external dimensions of the substrate using a microscope with a dimension measurement function. I did it. Further, the magnetic permeability was measured by an impedance analyzer “HP-4291A” (manufactured by Hewlett-Packard Company) by a high frequency current voltage method. Of the measurement results shown in Table 1, the shrinkage variation and the magnetic permeability of the entire substrate are based on data of the number of samples n = 5.

  From Table 1, in the case of the comparative example 1 whose thickness of the insulating layer 4 is 5 micrometers, the magnetic permeability was 120.2 and the magnetic permeability was falling significantly.

  On the other hand, the magnetic permeability of Examples 1 to 3 in which the thickness of the insulating layer 4 or the sintered metal layer 5 is 10 μm is 140.5, 143.3, and 141.1, respectively. The decline was small.

  This is because in Comparative Example 1 where the thickness of the insulating layer 4 is thin, the internal stress of the ferrite layer 2 due to the difference in thermal expansion between the glass ceramic insulating layer 6 and the ferrite layer 2 cannot be relaxed, and magnetostriction occurs in the ferrite layer 2. is there.

  Further, in the case of Comparative Example 2 including only the ferrite layer 2, the overall shrinkage of the evaluation substrate was as large as 16%, and the shrinkage variation was as large as ± 0.5%.

  On the other hand, the shrinkage of the whole substrates of Examples 1 and 2 which are the glass ceramic substrates of the present invention is 5%, which is smaller than that of Comparative Example 2, and the shrinkage variation is ± 0.2%, which is compared with that of Comparative Example 2. It was small. Further, the shrinkage of the whole substrate of Example 3 which is a glass ceramic substrate manufactured using a constrained green sheet is 0.5%, which is smaller than those of Examples 1 and 2, and the shrinkage variation is ± 0.1%. It was even smaller than in the case of Examples 1 and 2. That is, according to the glass ceramic substrate and the manufacturing method thereof of the present invention, it has been found that the shrinkage of the entire glass ceramic substrate can be suppressed and the shrinkage variation can also be suppressed.

  In Example 4, an evaluation substrate having an outer diameter of 50 mm × 50 mm and a thickness of 2 mm with a 2 mm × 2 mm insulating layer printed on the surface as shown in FIGS. 4 and 5 was prepared, and the tensile strength was measured. 4 and 5, the same reference numerals are given to the same portions as in FIG. 1, 2 is a ferrite layer, 4 is an insulating layer, and 6 is a glass ceramic insulating layer. The tensile strength was measured by bonding a tensile measurement jig to the insulating layer using a thermosetting resin and pulling the tensile measurement jig using MODEL-1310DW and MODEL 1011 (manufactured by AIKOH ENGINEERING).

  First, a glass ceramic green sheet and a ferrite green sheet were molded by the same method as in Example 1.

  Here, the softening temperature of the glass contained in the glass ceramic green sheet is 800 ° C., and the sintering start temperature of the ferrite green sheet is 750 ° C.

Next, the SiO ₂ —Al ₂ O ₃ —MgO—B ₂ O ₃ —ZnO-based glass powder having a softening temperature of 800 ° C., which is the same as the glass powder contained in the glass ceramic as the insulating paste, is 30% by mass, ferrite green sheet green sheet 70% by mass of ferrite powder composed of a crystal phase of ZnFe ₂ O ₄ , MnFe ₂ O ₄ , FeFe ₂ O ₄ , NiFe ₂ O ₄ having the same average particle diameter of 0.5 to 1 μm as the ferrite powder contained in A predetermined amount of ethylcellulose-based resin and terpineol were added and mixed to prepare an appropriate viscosity with three rolls.

  The glass ceramic green sheet, ferrite green sheet, and constrained green sheet were both processed into a substrate shape having an outer diameter of 50 mm × 50 mm and a thickness of 2 mm.

  First, a predetermined number of glass ceramic green sheets or ferrite green sheets were superposed, and an insulating paste layer was applied in a 2 mm × 2 mm shape thereon and dried. The insulating paste layer was 20 μm thick. Thereafter, the glass ceramic laminate or the ferrite laminate was obtained by pressure bonding at a temperature of 55 ° C. and a pressure of 20 MPa.

  The obtained glass ceramic laminate or ferrite laminate is placed on an alumina ceramic setter, and a weight of the same component as the alumina ceramic setter is placed on the glass ceramic laminate or ferrite laminate, and a load of about 0.5 MPa is applied to the atmosphere. The mixture was heated at 500 ° C. for 2 hours to remove organic components, and then baked at 900 ° C. for 1 hour in the air.

  The thickness of the insulating layer 4 of the obtained glass ceramic evaluation substrate or ferrite evaluation substrate after firing was 10 μm.

  Table 2 shows the results of measuring the tensile strength of the glass ceramic substrate of Example 4 obtained in this manner.

A substrate for evaluation of Example 5 was produced in the same manner as in Example 4 except that SiO ₂ —B ₂ O ₃ —ZnO-based glass having a softening point of 600 ° C. and a crystallization temperature of 850 ° C. was used in the insulating layer glass. did.

A substrate for evaluation of Example 6 was produced in the same manner as in Example 4 except that SiO ₂ —B ₂ O ₃ —ZnO-based glass having a softening point of 600 ° C. and a crystallization temperature of 700 ° C. was used in the insulating layer glass. did.

In the same manner as in Example 4 except that SiO ₂ —Al ₂ O ₃ —MgO—B ₂ O ₃ -based glass having a softening point of 800 ° C. and a crystallization temperature of 950 ° C. was used in the insulating layer glass. An evaluation substrate was prepared.

  The tensile strength of the evaluation substrates of Examples 4, 5, 6 and 7 produced in this way was measured. The measurement results are shown in Table 2.

In addition, the measurement result shown in Table 2 is based on the number of samples n = 5 data.

  From Table 2, the tensile strength of the joining layer using the glass whose crystallization temperature is higher than the glass contained in the glass ceramic in the measurement result of the glass ceramic evaluation substrate was high. Since the glass contained in the bonding layer diffused in the glass ceramic insulating layer exists as a liquid phase simultaneously with the glass contained in the glass ceramic insulating layer, the wettability of each other is good and the sintering of the glass ceramic insulating layer is promoted. This is because a strong bonding interface is formed at the interface between the insulating layer and the glass ceramic insulating layer. Further, in the measurement results of the ferrite evaluation substrate, the tensile strength of the bonding layer using glass having a softening point lower than the sintering start temperature of ferrite was high. Since the glass contained in the insulating layer diffuses into the ferrite layer earlier than the ferrite layer starts sintering and promotes the sintering of the ferrite layer as a liquid phase, a strong bonding interface is formed at the interface between the insulating layer and the ferrite layer This is because.

A to-be-fired product 7 was produced by the same production method as in Example 1, and the obtained to-be-fired product 7 was placed on a microwave-absorbing shelf board 13. As the material of the shelf board 13, SiC having higher microwave absorption than the ferrite layer 2 was used. Next, this to-be-fired thing 7 was enclosed with the housing | casing 8 of microwave absorption. As the material of the casing 8, alumina having the same level of microwave absorption as that of the ferrite layer 2 was used. By irradiating the object 7 to be fired through the casing 8 with microwaves, it was heated in the atmosphere at 500 ° C. for 2 hours to remove organic components, and then fired in the atmosphere at 900 ° C. for 1 hour. Table 3 below shows the results of measuring the overall shrinkage, shrinkage variation, magnetic permeability, and density of the ferrite layer 2 portion of the obtained glass ceramic substrate for evaluation.
(Comparative Example 3)

A to-be-fired product 7 was produced by the same production method as in Example 1, and the obtained to-be-fired product 7 was placed on a microwave-absorbing shelf board 13. The same material as in Example 8 was used as the material of the shelf board 13. Next, this to-be-fired thing 7 was enclosed with the housing | casing 8 of microwave absorption. As the material of the casing 8, mullite having a microwave absorption lower than that of the ferrite layer 2 was used. By irradiating the object 7 to be fired through the casing 8 with microwaves, it was heated in the atmosphere at 500 ° C. for 2 hours to remove organic components, and then fired in the atmosphere at 900 ° C. for 1 hour. Table 3 below shows the results of measuring the overall shrinkage, shrinkage variation, magnetic permeability, and density of the ferrite layer 2 portion of the obtained glass ceramic substrate for evaluation.
(Comparative Example 4)

  The to-be-baked thing 7 was produced with the manufacturing method similar to Example 1, and the obtained to-be-baked thing 7 was heated at 500 degreeC in air | atmosphere for 2 hours using the electric furnace, and after removing an organic component, air | atmosphere Baked at 900 ° C. for 1 hour. Table 3 below shows the results of measuring the overall shrinkage, shrinkage variation, magnetic permeability and density of the ferrite layer portion of the obtained glass ceramic substrate for evaluation.

Measurement of the shrinkage and shrinkage variation of the glass ceramic substrate for evaluation of Example 8 and Comparative Examples 3 and 4 produced as described above were performed, and the external dimensions of the glass ceramic substrate were measured using a microscope having a dimension measuring function. It was done by doing. In addition, the permeability was measured by an high frequency current voltage method using an impedance analyzer (“HP-4291A” manufactured by Hewlett Packard). Further, a glass ceramic substrate for evaluation was polished from the front surface and the back surface, the ferrite layer 2 portion was cut out, and the density was measured by Archimedes method. In addition, among the measurement results shown in Table 3, the shrinkage variation and the magnetic permeability are based on data with 5 samples.

From Table 3, the comparative example 4 baked using the electric furnace was as low as magnetic permeability 130.0 and density 4.90g / cm < ³ >. Moreover, the comparative example 3 which baked with the microwave using the mullite whose microwave absorptivity is lower than the ferrite layer 2 for the material of the housing | casing 8 was as high as magnetic permeability 143.0 and density 5.05g / cm < ³ >. However, the shrinkage variation was as large as ± 0.4%. Moreover, the warp of the glass ceramic substrate was also large.

On the other hand, the glass ceramic substrate of Example 8 of the present invention had a high magnetic permeability of 145.5, a density of 5.15 g / cm ³ and a small shrinkage variation of ± 0.15%. That is, according to the manufacturing method of the glass ceramic substrate of this invention, it turned out that the shrinkage variation of a glass ceramic substrate is small, the density of the ferrite layer 2 is high, and a glass ceramic substrate with high magnetic permeability can be produced.

  The present invention is not limited to the above-described embodiments and examples, and various modifications can be made without departing from the gist of the present invention. For example, although Ag is used for the wiring conductor 3 in the above-described embodiment, Cu, Au, Ag—Pd alloy, or the like may be used for the wiring conductor 3.

It is sectional drawing which shows an example of embodiment of the glass ceramic substrate of this invention. (A) shows an example of embodiment of the manufacturing method of the glass ceramic substrate of this invention, The top view of the microwave baking furnace used by this invention, (b) is the cross section in the AA 'line of (a) FIG. 4C is a sectional view taken along line BB ′ in FIG. It is sectional drawing which shows the test piece for evaluation used for the magnetic permeability measurement of the Example of this invention. It is a perspective view which shows the glass ceramic substrate for evaluation used for the tensile strength measurement of the Example of this invention. It is a perspective view which shows the ferrite substrate for evaluation used for the tensile strength measurement of the Example of this invention.

Explanation of symbols

1: Insulating substrate 2: Ferrite layer 3: Wiring conductor 4: Insulating layer 5: Sintered metal layer 6: Glass ceramic insulating layer 7: Firing object 8: Housing 9: Microwave firing furnace 13: Shelves 16: Firing Atmospheric gas

Claims (7)

The glass-ceramic insulation, which is formed by co-firing with the glass-ceramic insulating layer in an inner layer of an insulating substrate formed by laminating a plurality of glass-ceramic insulating layers made of glass and filler, and having a coil conductor embedded therein. A glass ceramic substrate in which a ferrite layer having the same size as the layer is formed with an intervening layer having a thickness of 10 μm or more formed of at least one of an insulating layer and a sintered metal layer between the glass ceramic insulating layer The ferrite layer has a higher thermal expansion coefficient than the glass and filler of the glass ceramic insulating layer, and the insulating layer is contained in the glass and the ferrite layer having a higher thermal expansion coefficient than the glass ceramic insulating layer. Containing the same ferrite, and the sintered metal layer is made of Cu, Ag, Au, t, glass-ceramic substrate, characterized by containing at least one metal and glass of the Ag-Pd alloy and Ag-Pt alloy. The ferrite is selected from at least one of ZnFe ₂ O ₄ , MnFe ₂ O ₄ , FeFe ₂ O ₄ , CoFe ₂ O ₄ , NiFe ₂ O ₄ , BaFe ₁₂ O ₄ , SrFe ₁₂ O ₄ and CuFe ₂ O _4. The glass ceramic substrate according to claim 1, wherein the glass ceramic substrate is formed. When the firing shrinkage start temperature and firing shrinkage end temperature of the glass ceramic insulating layer are T1 and T2, respectively, and the firing shrinkage start temperature and firing shrinkage end temperature of the ferrite layer are T3 and T4, respectively, T3 <T1 and T2 < 2. The glass ceramic substrate according to claim 1, wherein the glass ceramic substrate is T4. The softening temperature and crystallization temperature of the glass contained in the insulating layer are T5 and T6, the softening temperature of the glass contained in the glass ceramic insulating layer is T7, and the sintering start temperature of the ferrite layer is T8. 2. The glass ceramic substrate according to claim 1, wherein T5 <T8 and T7 <T6. A claim 1 process for producing a glass ceramic substrate, comprising: a plurality of glass ceramic green _{sheets, ZnFe 2 O 4, MnFe 2} O 4, FeFe 2 O 4, CoFe 2 O 4, NiFe 2 O 4, BaFe _At least two ferrite green sheets having at least one of ₁₂ O ₄ , SrFe ₁₂ O ₄ and CuFe ₂ O ₄ and having the same size as the glass ceramic green sheet and having a coil conductor disposed therebetween. A glass having a higher thermal expansion coefficient than the glass ceramic insulating layer, an insulating paste layer containing the same calcined ferrite powder as the ferrite contained in the ferrite layer, and a Cu, Ag, Au, Pt, Ag—Pd alloy, and Containing at least one metal powder and glass powder of Ag-Pt alloy With laminated via at least one metal paste layer, a process of forming a glass-ceramic green sheet laminate the top and bottom layers was the glass ceramic green sheet,
And a step of firing after removing the organic component from the glass ceramic green sheet laminate. A claim 1 process for producing a glass ceramic substrate, comprising: a plurality of glass ceramic green _{sheets, ZnFe 2 O 4, MnFe 2} O 4, FeFe 2 O 4, CoFe 2 O 4, NiFe 2 O 4, BaFe _At least two ferrite green sheets having at least one of ₁₂ O ₄ , SrFe ₁₂ O ₄ and CuFe ₂ O ₄ and having the same size as the glass ceramic green sheet and having a coil conductor disposed therebetween. A glass having a higher thermal expansion coefficient than the glass ceramic insulating layer, an insulating paste layer containing the same calcined ferrite powder as the ferrite contained in the ferrite layer, and a Cu, Ag, Au, Pt, Ag—Pd alloy, and Containing at least one metal powder and glass powder of Ag-Pt alloy With laminated via at least one metal paste layer, a process of forming a glass-ceramic green sheet laminate the top and bottom layers was the glass ceramic green sheet,
Laminating a constrained green sheet containing a non-sinterable inorganic material, glass and an organic binder on both upper and lower surfaces of the glass ceramic green sheet laminate;
Producing a glass ceramic substrate holding the restraint sheet by firing after removing organic components from the laminate of the restraint green sheet and the glass ceramic green sheet laminate;
Removing the constraining sheet from the glass ceramic substrate,
The glass content of the constraining green sheet is an amount that binds the constraining green sheet with the glass ceramic green sheet during the firing and does not substantially shrink the constraining green sheet in its laminated surface. A method for producing a glass ceramic substrate. In the manufacturing method of the glass ceramic substrate of Claim 5 or Claim 6, the laminated body of the said glass ceramic green sheet laminated body or the said restraint green sheet, and the said glass ceramic green sheet laminated body is a microwave absorptive housing | casing. The organic ceramic component is removed and fired by irradiating microwaves to the glass ceramic green sheet laminate or the laminate of the constrained green sheet and the glass ceramic green sheet laminate through the housing. A method for producing a glass-ceramic substrate.

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