JP2010053010A - Method for producing ceramic sintered compact and fixture for microwave heating - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a ceramic sintered compact which can produce a ceramic sintered compact whose deformation is suppressed and whose dimensional accuracy is high without requiring the control of the output of microwaves. <P>SOLUTION: The object to be fired is arranged at the inside of a microwave heating furnace so as to be in contact with a fixture for microwave heating, and is heated and fired, thus a ceramic sintered compact is produced. As the fixture for microwave heating, a fixture composed of SiC, Al<SB>2</SB>O<SB>3</SB>, SiO<SB>2</SB>and MgO, and in which the SiC content lies in the range of 30 to 65 wt.%, the Al<SB>2</SB>O<SB>3</SB>content lies in the range of 12 to 23 wt.%, the SiO<SB>2</SB>content lies in the range of 19 to 38 wt.% and the MgO content lies in the range of 4 to 9 wt.% is used. The fixture for microwave heating preferably has bulk density of 1.3 to 2.6 g/cm<SP>3</SP>and apparent porosity of 10 to 50%. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a ceramic sintered body and a jig for microwave heating, and more particularly, to a method for manufacturing a ceramic sintered body that is heated and fired using microwaves, and for microwave heating that is used during the heating and firing. It relates to a jig.

  In recent years, a frequency band used for a wiring board is shifting to a high frequency band exceeding GHz. In order to transmit a high-frequency signal at a high speed, the resistance of the conductor forming the wiring layer is required to be small, and a lower relative dielectric constant is also required for the insulating layer.

  For this reason, a multilayer wiring board using glass ceramics obtained by firing a mixture of glass and ceramics (inorganic filler) as an insulating layer has attracted attention.

  Since glass ceramics can be fired at a relatively low temperature of 800 to 1000 ° C., a low resistance metal such as Ag or Cu can be used for the wiring layer, and the conductor resistance can be lowered. Moreover, since the relative dielectric constant of the glass ceramic itself is low, the capacitance component of the wiring can be reduced, and a multilayer wiring board suitable for high-frequency signals can be realized.

  Recently, it has been proposed to use microwave heating when firing such a ceramic wiring board. Microwaves are preferable because they generate heat directly in the object to be fired, so that temperature variations during sintering of the object to be sintered are reduced.

  However, since glass, filler, and organic binder have a low microwave absorption rate particularly at a low temperature, it is difficult to heat the ceramic green sheet itself. Therefore, a material having a high microwave absorptivity such as silicon carbide (SiC) is used as a material for the mounting table (see Patent Document 1) on which the compact is placed in the heating furnace and the plates (see Patent Document 2) sandwiching the compact. In this way, heat assistance is performed.

JP 2004-51469 A JP 2004-168575 A

  However, as described in Patent Document 1, a method using a mounting table having a microwave absorption rate substantially equal to that of an object to be heated, or using a SiC plate as a heating auxiliary material as described in Patent Document 2. In the sintering method, the heat generation amount of the mounting table and the SiC plate is dependent on the temperature, so the heating value of the mounting table is not constant with respect to the output of the microwave. The rate is high, and the rate of temperature rise is low in the temperature range exceeding 800 ° C. Thus, when the rate of temperature increase is different, for example, in the temperature range of 800 ° C. or lower, the organic binder contained in the green sheet is rapidly burned (thermally decomposed), and the substrate after baking is deformed. In a temperature region exceeding the temperature range, the rate of temperature increase is reduced, and there arises a problem that densification of the substrate after baking is inhibited, or voids (voids) are formed in the substrate.

  In order to solve this problem, it is conceivable to control the output of the microwave, but it is actually difficult to control the output of the microwave so that the heating rate of the object to be heated is constant.

  The present invention has been made in view of the above problems, and is a ceramic sintered body capable of producing a ceramic sintered body with high dimensional accuracy in which deformation is suppressed without the need to control the output of the microwave. It is an object of the present invention to provide a manufacturing method and a microwave heating jig used in such a manufacturing method.

The present invention is a method for producing a ceramic sintered body by arranging a material to be fired so as to be in contact with a microwave heating jig in a microwave heating furnace, followed by heating and firing. The jig is composed of SiC, Al ₂ O ₃ , SiO ₂ and MgO, SiC is 30 to 65% by weight, Al ₂ O ₃ is 12 to 23% by weight, SiO ₂ is 19 to 38% by weight, and MgO is 4 to 4%. A jig composed of a member in the range of 9% by weight is used.

In the manufacturing method of the ceramic sintered body, the members constituting the microwave heating jig is preferably a bulk density 1.3~2.6g / cm ^3.

  In the method for producing a ceramic sintered body, the member constituting the microwave heating jig preferably has an apparent porosity of 10 to 50%.

The present invention is a heating jig for producing a ceramic sintered body by being placed in contact with an object to be fired in a microwave heating furnace and heated and fired, and the heating jig is made of SiC. Of SiC, Al ₂ O ₃ , SiO ₂ and MgO, SiC in the range of 30 to 65% by weight, Al ₂ O _{3 in the range} of 12 to 23% by weight, SiO _{2 in} the range of 19 to 38% by weight, and MgO in the range of 4 to 9% by weight It is comprised with the member which is.

The member constituting the heating jig preferably has a bulk density of 1.3 to 2.6 g / cm ³ .

  Further, the member constituting the heating jig preferably has an apparent porosity of 10 to 50%.

  According to the method for producing a ceramic sintered body of the present invention, it is not necessary to control the output of the microwave, and a ceramic sintered body with higher dimensional accuracy in which deformation is suppressed can be obtained.

  According to the microwave heating jig of the present invention, it is possible to obtain a ceramic sintered body with higher dimensional accuracy, in which deformation is suppressed, by placing it in contact with the object to be fired and heating and firing.

  Hereinafter, a method for producing a ceramic substrate of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a cross-sectional view showing a configuration example of a ceramic wiring board manufactured by the method for manufacturing a ceramic sintered body according to the present invention. The ceramic wiring board 7 is configured to include a multilayer substrate 1 in which a predetermined circuit is formed by wiring conductors, and surface wiring conductors 4 and 5 and thick film resistors are provided on the main surface of the multilayer substrate 1 as necessary. A film, a protective film, and the like are formed, and various electronic components 6 bonded to the surface wiring conductors 4 and 5 are further configured.

  The multilayer substrate 1 includes ceramic insulating layers (hereinafter simply referred to as “insulating layers”) 1a to 1e, an internal wiring conductor 2, and a via-hole conductor 3, and a predetermined circuit is provided therein.

  As the insulating layers 1a to 1e, glass ceramic materials that can be fired at a relatively low temperature of, for example, about 800 to 1000 ° C. are used.

  The glass-ceramic material mainly contains an inorganic filler and a glass component, and examples of the inorganic filler include corundum (α alumina), cristobalite, quartz, mullite, and cordierite.

  Further, the glass component is made of low melting point crystallized glass containing a plurality of metal oxides, for example, cordierite, mullite, anorthite, serdian, by firing at a relatively low temperature of about 800 to 1000 ° C. At least one crystal phase of spinel, garnite, willemite, dolomite, petalite and substituted derivatives thereof is precipitated.

  The internal wiring conductor 2 and the via-hole conductor 3 are Ag-based (Ag simple substance, Ag alloy such as Ag-Pd), Cu-based (Cu simple substance, Cu alloy), Pd-based (Pd simple substance, Pd alloy), or Pt (Pt The internal wiring conductor 2 has a thickness of about 8 to 15 μm, and the diameter of the via-hole conductor 3 can be set to an arbitrary value, for example, 50 to 250 μm.

  By using the above materials for the internal wiring conductor 2 and the via-hole conductor 3, the wiring conductor is reliably heated by microwaves, and the inside of the substrate can be heated as well as the surface of the substrate.

  The surface wiring conductors 4 and 5 are made of Ag-based (Ag simple substance, Ag alloy such as Ag-Pd), Cu-based (Cu simple substance, Cu alloy), Pd-based (Pd simple substance, Pd alloy), or Pt (Pt simple substance, Pt). For example, it is already formed on the laminate substrate 1 before being fired.

A thick film resistor film and a protective film are formed on the surface wiring conductors 4 and 5 of the multilayer substrate 1, and a chip capacitor, chip resistor, transistor, or IC (Integrated) is formed.
Various electronic components 6 such as Circuit) are mounted so as to be electrically conductive with the surface wiring conductors 4 and 5 by soldering or wire bonding.
Below, the manufacturing method of the ceramic wiring board 7 is demonstrated.

(Green sheet and conductive paste preparation process)
First, ceramic green sheets to be the insulating layers 1a to 1e are prepared, and a low resistance metal material (Ag,) for forming conductor films and conductors to be the internal wiring conductor 2, the via-hole conductor 3, and the surface wiring conductors 4 and 5 is prepared. Cu, Pd, Pt, or an alloy thereof), additive having a high relative dielectric constant (SiC, TiO ₂ , ZrO ₂ , MgO, AlN, Cr ₂ O ₂ , ZnO, and Si ₃ N ₄₎ Conductive paste made of seeds or more), glass frit, and organic vehicle are prepared.

  The ceramic green sheet is formed by homogenously kneading a low melting point crystallized glass frit, an inorganic filler, a binder, and a solvent, forming a tape by a doctor blade method or the like, and cutting it into a predetermined size.

  As described above, the low-melting crystallized glass frit is obtained by firing at a relatively low temperature of about 800 to 1000 ° C., so that cordierite, mullite, anorthite, serdian, spinel, garnite, willemite, dolomite, It consists of a glass composition in which at least one crystal phase of petalite and substituted derivatives thereof is precipitated, and the average particle size is 1.0 to 6.0 μm, preferably 1.5 to 3.5 μm.

In particular, if a glass frit that precipitates anorthite or serdian is used, a laminate substrate 1 having higher strength can be obtained. If a glass frit that precipitates cordierite or mullite is used, a laminate having a low thermal expansion coefficient can be obtained. The body substrate 1 can be obtained and is effective as a laminate substrate for mounting a silicon chip having a low coefficient of thermal expansion such as an IC bare chip on the laminate substrate 1. In addition, in order to obtain the laminated substrate 1 having high strength and low coefficient of thermal expansion, as a glass composition on which anorthite and cordierite are simultaneously precipitated, for example, B ₂ O ₃ , SiO ₂ , Al ₂ O ₃ , ZnO, Alternatively, alkaline earth metal oxide is effective.

  The inorganic filler serves as an aggregate of the laminate substrate 1 and can be exemplified by ceramics such as corundum (α alumina), cristobalite, quartz, mullite, or cordierite, and the particle size thereof is 1.0 to 6.0 μm. The thickness is preferably 1.5 to 4.0 μm.

  The binder must be wettable with solid components (glass frit, inorganic filler) and have good thermal decomposability. Since the viscosity of the slip is determined at the same time, an ethylenically unsaturated compound having a carboxyl group or an alcoholic hydroxyl group such as an acrylic acid or methacrylic acid polymer is preferable. As an addition amount, it is preferable that it is 25 wt% or less with respect to all the solid components.

  As the solvent, an organic solvent or an aqueous solvent can be used. When an aqueous solvent is used, the binder needs to be water-soluble. It is preferable that a hydrophilic functional group such as a carboxyl group is added to the water-soluble binder, and the addition amount is 2 to 300 mgKOH / g, preferably 5 to 100 mgKOH / g in terms of acid value. .

  The above-mentioned binder and solvent must be completely thermally decomposed in the binder drying process of the thermal drying step by the doctor blade method and the firing step of the laminate substrate, and in particular, decomposed at 600 ° C. or less, preferably 500 ° C. or less. Good material to do.

  The constituent ratio of the above-mentioned inorganic filler and glass component is 10 wt% to 50 wt%, preferably 20 wt% to 35 wt% for the inorganic filler, and 50 wt% to 90 wt%, preferably 65 wt% to 80 wt% for the glass component. .

  When the inorganic filler is 10 wt% or more, that is, the glass component is 90 wt% or less, the proportion of the glassy material in the insulating layer is appropriate, the strength of the laminate substrate 1 is maintained, and the inorganic filler is 50 wt% or less, When the glass component is 50 wt% or more, the denseness of the multilayer substrate 1 can be maintained well.

(Drilling and paste printing process)
Next, through holes are formed with an NC punch or the like in consideration of the position where the via-hole conductor 3 is formed in the green sheets to be the insulating layers 1a to 1e, and subsequently filled with the above-described conductive paste, The through-hole is filled with a conductor paste, and a conductor film to be the internal wiring conductor 2 is printed on the surface of the green sheet so as to have a predetermined circuit shape.

(Lamination process)
Green sheets filled with through-holes and printed with wiring are stacked in consideration of the stacking order so as to become insulating layers 1a to 1e, and thermocompression-bonded to obtain an unfired stacked substrate.

(Baking process)
FIG. 2 is a diagram showing a configuration of a microwave firing furnace used when firing an unfired laminated substrate, FIG. 2 (a) is a plan view of the microwave firing furnace, and FIG. ) Is a cross-sectional view taken along line AA ′ in FIG.

  As shown in FIG. 2, in the microwave baking furnace 17, a housing 9 covered with the heat insulating material 10 is disposed in the internal space of the furnace wall 16. In the internal space of the housing 9, a plurality of shelf boards 8 on which the unfired laminated substrate 1 is placed are provided at predetermined intervals in the vertical direction by the columns 11. The internal space of the housing 9 communicates with the outside of the furnace wall 16 by the atmospheric gas supply nozzle 12 and the exhaust nozzle 14, and the atmospheric gas 13 passes from the outside through the atmospheric gas supply nozzle 13 to the housing 9. The exhaust gas 15 is supplied to the internal space, and discharged from the internal space of the housing 9 to the outside through the exhaust nozzle 14.

  As a firing method using microwaves, first, the unfired laminated substrate 1 itself is self-heated by the microwave introduced into the microwave firing furnace 17 through the waveguide, and is provided in the microwave firing furnace 17. The laminated substrate 1 is also sintered by the self-heating of the casing 9 and the shelf board 8 at the same time.

Here, the shelf board 8 has microwave absorptivity. The shelf board 8 is made of SiC, Al ₂ O ₃ , SiO ₂ and MgO, SiC is 30 to 65 wt%, Al ₂ O ₃ is 12 to 23 wt%, SiO ₂ is 19 to 38 wt%, and MgO is 4 wt%. It is comprised with the member which is the range of -9 weight%.

  When there is too little SiC in the shelf board 8, since the microwave absorbed by the shelf board 8 will decrease, a microwave acts on a to-be-baked object comparatively much, and a binder removal defect and temperature nonuniformity generate | occur | produce. Further, when a ceramic sintered body including a metal wiring such as a ceramic wiring board is manufactured, a microwave electric field concentrates on the metal wiring, and local heating due to sparks occurs. If SiC is 30% or more, it is possible to suppress the occurrence of binder removal failure and temperature unevenness in the object to be fired, and even when a ceramic sintered body such as a ceramic wiring board is manufactured, local heating is suppressed. be able to.

  Further, SiC is characterized by high microwave heat generation in a relatively low temperature region of 800 ° C. or lower. Since the microwave heat generation characteristic of the ceramic sintered body made of an inorganic oxide is low in the low temperature region, if the amount of SiC is too small, the heat generation property of the entire in-furnace component becomes poor, and the heating efficiency is deteriorated. If SiC is 30% or more, baking with good heating efficiency can be performed.

  On the other hand, SiC has a feature that the microwave heat generation characteristics are lowered in a temperature range of 800 ° C. or higher. Therefore, if SiC is excessive, heat generation at a sintering temperature of about 800 to 1000 ° C. is lowered. That is, if the SiC content in the shelf plate 8 is too large, the heat generation characteristics in the high temperature region are deteriorated, and the heat generation characteristics for achieving a constant temperature increase rate from the low temperature region to the high temperature region cannot be obtained. That is, the characteristics of SiC, which has high heat generation in the low temperature region and low heat generation in the high temperature region, clearly appear. If SiC is 65% or less, the fall of the heat-generating characteristic in a high temperature range can be suppressed.

  In addition, when SiC is 40% or more and 50% or less, the above effect can be obtained more remarkably.

  Also, cordierite composed of alumina, silica, and magnesia component tends to have high microwave heat generation characteristics in a high temperature region. Therefore, by using the shelf board 8 as a composite material of cordierite and SiC, A material having a constant heat generation characteristic from the region to the high temperature region can be obtained.

  The shelf board 8 becomes SiC and cordierite as a mineral composition. Since metal oxides such as alumina generally increase in dielectric loss with increasing temperature, a material having heat generation characteristics with little temperature dependency can be obtained by combining with SiC. However, a high thermal shock resistance is required for the shelf board 8 used in the firing furnace. Since oxides such as alumina and magnesia have a high thermal expansion coefficient, thermal shock resistance is reduced when compounded with SiC. For this reason, cordierite and SiC having a high microwave heat generation characteristic and a low thermal expansion coefficient in a high temperature region are preferably combined.

Cordierite can obtain the above effect more remarkably when Al ₂ O ₃ is in the range of 17 to 20% by weight, SiO ₂ is in the range of 27 to 32% by weight, and MgO is in the range of 6 to 8% by weight. it can.

In the case of a continuous furnace, the shelf board 8 should be lightweight in order to suppress the amount of heat taken out to the cooling zone. Moreover, in order to discharge | emit the binder generated from a product efficiently, the higher the porosity of the member which comprises the shelf board 8 is good. However, since the firing of the ceramic wiring board is performed in a multi-stage stack, a sufficient strength that can withstand the multi-stage stack is required. Therefore, the bulk density of the member constituting the shelf plate 8 1.3~2.6g / cm ^3, an apparent porosity is preferably 10-50%. Moreover, if the porosity of the shelf board 8 is 10 to 50%, the degassing generated when the organic binder contained in the ceramic green sheet is burned out easily.
Here, the bulk density and the apparent porosity are values measured by the Archimedes method.

Such a shelf board 8 can be manufactured as follows. First, SiC and raw materials such as Al ₂ O ₃ , SiO ₂ , MgO, clay adjusted to have a cordierite composition, and a pore forming material added to adjust the porosity are mixed by a mixer, and an appropriate amount is mixed. Add water and knead. Then, the kneaded clay is formed into a plate shape by uniaxial pressing. Next, after drying the plate-shaped molded body, the pore forming material is burned and removed at 800 ° C. using a gas furnace to obtain a calcined body. Then, the calcined body is fired at 1200 to 1300 ° C. in a nitrogen atmosphere in an electric furnace to obtain a sintered body. The obtained sintered body is ground into a predetermined shape to obtain a final shape shelf board 8.

  Moreover, the housing 9 has microwave heat generation properties. As a material of the housing 9, a ceramic material having a large dielectric loss (tan δ) and high microwave absorption is preferable. Moreover, as a ceramic material which comprises such a housing | casing 9, a silicon carbide type material or an alumina type material etc. are mentioned, for example.

  In addition, when the atmospheric gas 13 is supplied from the cylindrical atmospheric gas supply nozzle 12 into the housing 9, decomposition caused by thermal decomposition of the binder contained in the unfired laminate substrate 1 by microwave irradiation. The gas is discharged out of the furnace as the exhaust gas 15 from the exhaust nozzles 14 on the side surfaces which face each other without staying in the housing 9.

  The firing atmosphere is performed in an air (oxidizing) atmosphere or a neutral atmosphere. For example, when a Cu-based conductor is used for the internal wiring conductor 2 or the like, it is performed in a reducing atmosphere or a neutral atmosphere.

  The firing process for firing the unfired laminate substrate 1 includes a binder removal process and a sintering process.

  First, in the binder removal process, the organic component contained in the green sheet layer that becomes the insulating layers 1a to 1e, the conductor film that becomes the internal wiring conductor 2, and the paste that becomes the via-hole conductor 3 is burned out. In the temperature range.

  Next, in the sintering process, the crystallized glass component contained in the green sheet layer to be the insulating layers 1a to 1e undergoes a precipitation reaction of a predetermined crystal phase, and at the same time, is uniformly dispersed at the grain boundaries of the inorganic filler. Thereby, the strong laminated substrate 1 is obtained.

  Moreover, in the conductor film used as the internal wiring conductor 2 and the paste used as the via-hole conductor 3, for example, Ag-based powder is grown to reduce the resistance and integrated with the insulating layers 1a to 1e. Such a sintering process is performed in a temperature range that reaches a peak temperature of 800 to 1000 ° C.

In the method for manufacturing a ceramic sintered body according to the present embodiment, the shelf board 8 is made of SiC, Al ₂ O ₃ , SiO ₂ and MgO, SiC is 30 to 65 wt%, and Al ₂ O ₃ is 12 to 23 wt%. , composed of SiO ₂ is 19-38% by weight, in the range MgO is 4-9 wt% member. Therefore, since the rate of temperature increase of the shelf board 8 in the firing step is constant, warpage and deformation of the laminate substrate 1 can be reduced.

(Surface treatment process)
Surface treatment is performed on both main surfaces of the fired laminate substrate 1. Surface wiring conductors 4 and 5 are formed on the main surface on the upper surface side of the multilayer substrate 1 by, for example, printing, drying and baking of a copper-based conductive paste so as to be connected to the via-hole conductor 3 formed in the insulating layers 1a and 1e. To do.

  Here, the copper-based surface wiring conductors 4 and 5 and the silver-based via-hole conductor 3 are joined. For this reason, considering the eutectic temperature of silver and copper, select a copper-based conductive paste that can be fired at a low temperature (for example, 780 ° C. or lower), and reduce it to suppress copper oxidation. In a neutral or neutral atmosphere.

  Then, if necessary, a thick film resistive film and a protective film are baked, and various electronic components 6 are surface-mounted.

  In addition, about the above-mentioned embodiment, when the surface wiring conductors 4 and 5 of the multilayer substrate 1 are formed of, for example, a conductive paste that is simultaneously fired in the firing step of the multilayer substrate 1, the surface wiring conductors in the lamination step A conductive film to be 4 and 5 may be formed and integrated with the firing of the multilayer substrate 1.

  In addition, if necessary, a division groove may be formed in an unfired laminated substrate, and the division treatment may be performed immediately after firing or after the surface treatment process.

  Examples and Comparative Examples of the present invention were prepared as follows and evaluated for delamination, cracks, substrate warpage, and shrinkage variation.

  Delamination and cracks were confirmed visually. The case where no delamination or a crack was confirmed was evaluated as ◯, and the case where the crack was confirmed was evaluated as ×.

  The warpage of the substrate was measured with an image measuring instrument (manufactured by Mitutoyo Corporation), and the shrinkage variation was measured with a three-dimensional shape measuring instrument (manufactured by Keyence Corporation).

Example 1
A green sheet having a thickness of 150 μm was prepared, and a conductive film was formed on the green sheet by screen printing using an Ag-based conductive paste, and then laminated and thermocompression bonded to produce a laminate substrate.

The manufactured laminate substrate is placed in a case of SiC-based material that self-heats by microwaves, air is supplied into the case, and 2.45 GHz microwaves are continuously irradiated to remove organic components. Baking to 900 ° C. Further, the shelf plate in the firing furnace has 45% by weight of SiC, 18% by weight of Al ₂ O _3, 30% by weight of SiO _{2 and} 7% by weight of MgO, and a bulk density of 2.2 g / cm ^3. A member having an apparent porosity of 23% was used.

  After firing, the warp of the obtained ceramic substrate was as good as 35 μm, and there was no delamination or crack between the layers. The dimensional accuracy (shrinkage variation) was as good as ± 0.05%.

(Example 2)
On the shelf in the firing furnace, SiC is 30 wt%, Al ₂ O ₃ is 23 wt%, SiO ₂ is 38 wt%, MgO is 9 wt%, bulk density is 2.0 g / cm ³ , apparent porosity A ceramic substrate was obtained in the same manner as in Example 1 except that a member having a rate of 25% was used.

  The warp of the obtained ceramic substrate was as good as 45 μm, and there was no delamination or crack between the layers. The dimensional accuracy (shrinkage variation) was as good as ± 0.08%.

(Example 3)
On the shelf in the firing furnace, SiC is 65% by weight, Al ₂ O ₃ is 12% by weight, SiO ₂ is 19% by weight, MgO is 4% by weight, the bulk density is 2.3 g / cm ³ , and apparent pores A ceramic substrate was obtained in the same manner as in Example 1 except that a member having a rate of 21% was used.

  The warp of the obtained ceramic substrate was as good as 50 μm, and there was no delamination or crack between the layers. The dimensional accuracy (shrinkage variation) was as good as ± 0.09%.

Example 4
On the shelf in the firing furnace, SiC is 30 wt%, Al ₂ O ₃ is 23 wt%, SiO ₂ is 38 wt%, MgO is 9 wt%, bulk density is 1.3 g / cm ³ , apparent porosity A ceramic substrate was obtained in the same manner as in Example 1 except that a member having a rate of 50% was used.

  The warp of the obtained ceramic substrate was as good as 40 μm, and there was no delamination or crack between the layers. The dimensional accuracy (shrinkage variation) was as good as ± 0.09%.

(Example 5)
The shelves in the firing furnace, SiC is 65% by weight, _Al 2 _{O 3} is 12 wt%, SiO ₂ is 19 wt%, MgO is 4 wt%, bulk density 2.6 g / cm ^3, an apparent porosity A ceramic substrate was obtained in the same manner as in Example 1 except that a member having a rate of 10% was used.
The warp of the obtained ceramic substrate was as good as 55 μm, and there was no delamination or crack between the layers. The dimensional accuracy (shrinkage variation) was as good as ± 0.10%.

(Example 6)
On the shelf in the firing furnace, SiC is 50 wt%, Al ₂ O ₃ is 17 wt%, SiO ₂ is 27 wt%, MgO is 6 wt%, bulk density is 2.2 g / cm ³ , apparent pores A ceramic substrate was obtained in the same manner as in Example 1 except that a member having a rate of 23% was used.

  The warp of the obtained ceramic substrate was very good at 40 μm, and there was no delamination or crack between the layers. Further, the dimensional accuracy (shrinkage variation) was very good at ± 0.06%.

(Example 7)
The shelves in the firing furnace, SiC is 40 wt%, _Al 2 _{O 3} is 20 wt%, SiO ₂ 32 wt%, MgO is 8 wt%, bulk density 2.0 g / cm ^3, an apparent porosity A ceramic substrate was obtained in the same manner as in Example 1 except that a member having a rate of 25% was used.

  The warp of the obtained ceramic substrate was very good at 40 μm, and there was no delamination or crack between the layers. Further, the dimensional accuracy (shrinkage variation) was very good at ± 0.07%.

(Comparative Example 1)
On the shelf in the firing furnace, SiC is 25% by weight, Al ₂ O ₃ is 26% by weight, SiO ₂ is 39% by weight, MgO is 10% by weight, bulk density is 2.0 g / cm ³ , apparent porosity A ceramic substrate was obtained in the same manner as in Example 1 except that a member having a rate of 26% was used.

  Although the obtained ceramic substrate had no delamination or cracks, the warp was as large as 95 μm, and the dimensional accuracy (shrinkage variation) was as large as ± 0.21%.

(Comparative Example 2)
The shelves in the firing furnace, SiC is 70 wt%, _Al 2 _{O 3} is 10 wt%, SiO ₂ of 16 wt%, MgO is 4 wt%, bulk density 2.4 g / cm ^3, an apparent porosity A ceramic substrate was obtained in the same manner as in Example 1 except that a member having a rate of 20% was used.

  Although the obtained ceramic substrate had no delamination or cracks, the warp was as large as 105 μm, and the dimensional accuracy (shrinkage variation) was as large as ± 0.22%.

(Comparative Example 3)
On the shelf in the firing furnace, SiC is 47 wt%, Al ₂ O ₃ is 10 wt%, SiO ₂ is 40 wt%, MgO is 3 wt%, bulk density is 2.1 g / cm ³ , apparent porosity A ceramic substrate was obtained in the same manner as in Example 1 except that a member having a rate of 24% was used.

  The warp of the obtained ceramic substrate was as good as 60 μm, and there was no delamination or crack between the layers. Further, the dimensional accuracy (shrinkage variation) was as large as ± 0.21%.

(Comparative Example 4)
On the shelf in the firing furnace, SiC is 25% by weight, Al ₂ O ₃ is 30% by weight, SiO ₂ is 35% by weight, MgO is 10% by weight, bulk density is 1.3 g / cm ³ , apparent pores A ceramic substrate was obtained in the same manner as in Example 1 except that a member having a rate of 45% was used.

  The obtained ceramic substrate had delamination and cracks between layers, warpage was as large as 100 μm, and dimensional accuracy (shrinkage variation) was as large as ± 0.24%.

(Comparative Example 5)
On the shelf in the firing furnace, SiC is 25% by weight, Al ₂ O ₃ is 26% by weight, SiO ₂ is 39% by weight, MgO is 10% by weight, bulk density is 1.2 g / cm ³ , apparent porosity A ceramic substrate was obtained in the same manner as in Example 1 except that a member having a rate of 60% was used.

  Although the obtained ceramic substrate had no delamination or cracks, the warpage was as large as 90 μm, and the dimensional accuracy (shrinkage variation) was as large as ± 0.20%.

(Comparative Example 6)
The shelves in the firing furnace, SiC is 70 wt%, _Al 2 _{O 3} is 11 wt%, SiO ₂ of 16 wt%, MgO is 3 wt%, bulk density 2.7 g / cm ^3, an apparent porosity A ceramic substrate was obtained in the same manner as in Example 1 except that a member having a rate of 7% was used.

Although the obtained ceramic substrate had no delamination or cracks, the warp was as large as 110 μm, and the dimensional accuracy (shrinkage variation) was as large as ± 0.25%.
The above results are summarized in Table 1.

  In each of Examples 1 to 7, delamination and cracks were not observed, and substrate warpage and shrinkage variation were suppressed to a small level. In particular, in Example 1, both the warpage of the substrate and the shrinkage variation were the smallest.

  In Comparative Examples 1 to 6, no delamination and cracks were observed, but the shrinkage variation was large, and the warpage of the substrate was large except for Comparative Example 3.

It is sectional drawing which shows the structural example of the ceramic wiring board manufactured by the manufacturing method of the ceramic sintered compact of this invention. It is a figure which shows the structure of the microwave baking furnace used when baking the laminated body board | substrate of an unbaking state, (a) is a top view, (b) is in sectional plane line AA 'of (a). It is sectional drawing.

Explanation of symbols

8 shelf plate 9 housing 10 heat insulating material 11 support 12 atmosphere gas supply nozzle 13 atmosphere gas 14 exhaust nozzle 15 exhaust gas 16 furnace wall

Claims (6)

In a microwave heating furnace, a method for producing a ceramic sintered body by placing a material to be fired so as to be in contact with a microwave heating jig, followed by heating and firing, and as the microwave heating jig, It is composed of SiC, Al ₂ O ₃ , SiO ₂ and MgO, SiC is 30 to 65% by weight, Al ₂ O ₃ is 12 to 23% by weight, SiO ₂ is 19 to 38% by weight, and MgO is 4 to 9% by weight. A method for producing a ceramic sintered body characterized by using a jig composed of a member in a range. The method for producing a ceramic sintered body according to claim 1, wherein the member constituting the microwave heating jig has a bulk density of 1.3 to 2.6 g / cm ³ .   The method for producing a ceramic sintered body according to claim 1 or 2, wherein the member constituting the microwave heating jig has an apparent porosity of 10 to 50%. A heating jig for producing a ceramic sintered body by being placed in contact with an object to be fired and heated and fired in a microwave heating furnace, comprising SiC, Al ₂ O ₃ , SiO ₂ and MgO Characterized in that it is composed of a member in which SiC is 30 to 65% by weight, Al ₂ O ₃ is 12 to 23% by weight, SiO ₂ is 19 to 38% by weight, and MgO is 4 to 9% by weight. Microwave heating jig. The jig for microwave heating according to claim 4, wherein a bulk density of the member is 1.3 to 2.6 g / cm ³ .   The microwave heating jig according to claim 4, wherein the apparent porosity of the member is 10 to 50%.

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