JP2007284297A - Green sheet, multilayer substrate using the same and method of manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a glass-ceramic green sheet which has low density and good air permeability and can ensure low-temperature sinterability and realize a stacking property and the low-temperature sinterability that are essential to manufacturing of a small, high-performance glass-ceramic multilayer substrate, and a method of manufacturing the glass ceramic multilayer substrate realizing the small, high-performance glass-ceramic multilayer substrate. <P>SOLUTION: The ceramic green sheet contains at least a glass-ceramic powder containing a ceramic powder 301 and a glass powder 302 and an organic binder. The glass-ceramic power is a powder subjected to a heat-treatment at a temperature equal to or above the glass transition temperature of the glass powder 302 but below the softening point thereof. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a green sheet used for a multilayer substrate such as a capacitor or inductor having a multilayer structure, or a multilayer composite component including these, and a multilayer substrate using the same.

  In recent years, production of ceramic multilayer substrates such as capacitors and inductors having a multilayer structure, or multilayer composite parts including these has been progressing for the purpose of downsizing and higher functionality of electronic components.

  Below, the manufacturing process of a ceramic multilayer substrate is demonstrated using FIGS. 9-12.

  FIG. 9 is a cross-sectional view showing the manufacturing process of the ceramic multilayer substrate.

  Predetermined amounts of one or more kinds of inorganic powder as a raw material and a binder, a dispersant, a plasticizer, a dispersion medium, etc. are mixed to form a slurry, which is mixed and dispersed by a medium stirring mill or the like to prepare a slurry.

  Next, the slurry is coated on the film by controlling the film thickness by a doctor blade method or a die coating method, and dried to obtain a green sheet 1201 having a uniform density and thickness.

  As shown in FIG. 9 (a), a hole called a via hole 1202 is formed on the green sheet 1201 by punching or laser as necessary, and then the conductive paste is formed by screen printing. Print on the printed part to fill the hole. Thereafter, wiring electrodes 1203 having a designed circuit pattern are formed again on the surface of the green sheet 1201 by a conductor layer, specifically, screen printing using a conductive paste, patterning using a photosensitive conductive paste, or a plating method.

  Next, a plurality of these green sheets 1201 are laminated with high positional accuracy so that the wiring electrodes 1203 of the circuit pattern formed on each sheet are electrically connected, and a laminate as shown in FIG. 9B. 1204 is manufactured. Then, a surface layer electrode 1206 is formed on the laminate 1204 using a conductive paste. Further, pressurization is performed in the direction perpendicular to the sheet surface. These are subjected to deplasticizer, debinding, firing and the like at a predetermined temperature.

  Finally, as shown in FIG. 9C, external electrodes 1301 are formed on both end faces of the fired laminate 1204, and plating on the external electrodes 1301 and mounting of surface parts 1302 are performed as necessary. A glass ceramic multilayer substrate 1303 is obtained. A substrate of this type that is co-fired with a good conductor having a low melting point of Ag or Cu, particularly at a low temperature, is referred to as a LTCC (Low Temperature Co-fired Ceramics) substrate.

  FIG. 10 is a cross-sectional view of a laminate in which delamination occurs, and FIG. 11 is a process cross-sectional view for explaining a mechanism in which delamination occurs.

  In the manufacturing process of the ceramic multilayer substrate, when a plurality of green sheets printed with electrodes are stacked and pressed, the green sheets of each other are prevented so that delamination 1205 of the laminate 1204 as shown in FIG. 10 does not occur. The adhesiveness (lamination property) at the interface is required to be good. The adhesion is strongly influenced by the air permeability and thickness direction compressibility of the green sheet, and a green sheet having good air permeability and high thickness direction compressibility is required. In general, air permeability and compressibility have a correlation with green sheet density, so to improve lamination, reduce the density of green sheets, increase the air permeability and increase the thickness of the green sheet when laminated and pressed. The compression ratio in the direction must be increased.

  This is because when the green sheets 1201 are stacked and pressed together with the wiring electrodes 1203 sandwiched between them as shown in FIG. 11A, the steps corresponding to the film thickness of the wiring electrodes 1203 are formed as shown in FIG. Because it must be filled. If this step cannot be filled, as shown in FIG. 11C, the air 1401 existing in the step portion cannot escape to the outside of the laminate, resulting in poor stacking, that is, delamination. In particular, the air permeability of the green sheet is important. If air remains even in the stepped portion of the electrode, delamination occurs from the above portion in the firing step.

  In particular, with the recent trend toward higher integration of multilayer electronic components, the trend toward thinner green sheets is increasing. The ratio of the electrode thickness to the green sheet thickness tends to increase, and in some cases, the electrode thickness may be thicker than the green sheet thickness.

  Further, when the density of the green sheets 1201 is high as shown in FIG. FIG. 12 is a schematic diagram of the electrode shape. When the electrode paste 1207 is printed on the green sheet 1201 as shown in FIG. 12A, the solvent contained in the electrode paste 1207 as shown in FIG. The 1501 component is not quickly absorbed by the green sheet 1201, so that electrode bleeding occurs, causing a short circuit failure when the required line space width is narrow.

  On the other hand, as shown in FIG. 12B, when the density of the green sheet 1201 is low, the solvent 1501 component contained in the electrode paste 1207 is easily absorbed, so that the occurrence of bleeding is suppressed.

  In order to achieve the above object, a green sheet having higher air permeability (air permeability) / compressibility and ensuring sinterability is required.

As a conventional ceramic green sheet, for example, a ceramic green sheet containing at least a ceramic powder and an organic binder, wherein the ceramic powder is at least 5 to 40% by heat treatment after mixing, calcining and pulverizing ceramic raw materials. The thing (for example, refer patent document 1) which included the ceramic powder which reduced the specific surface area as a main component is disclosed. Examples of the ceramic raw material include a ferrite ceramic raw material containing Ni, Zn, and Cu, and a dielectric ceramic raw material containing at least Ti, Ba or Ti, Pb.
Japanese Patent Laid-Open No. 10-45478

  However, in the above conventional configuration, although the air permeability of the ceramic green sheet can be increased, the air permeability is not sufficient because the reduction ratio of the specific surface area due to the heat treatment is small. Therefore, when the heat treatment temperature is increased, the ceramic powders begin to neck each other and the particle size increases, so that there is a disadvantage that the sinterability of the green sheet is extremely deteriorated. For this reason, ceramic powders that have been refined in size for firing at low temperatures, or ceramic powders that need to be fired simultaneously with Ag and Cu, which are low melting point conductors, exhibit sinterability even with a slight increase in particle size. There was a problem that this method could not be used because of the significant deterioration.

  Therefore, the present invention is a glass ceramic that can secure low-temperature sinterability while having high air permeability, and can achieve both laminarity, which is indispensable for the production of small and high-performance multilayer substrates, and simultaneous firing of conductors with low melting points at low temperatures It is an object of the present invention to provide a green sheet, a glass ceramic multilayer substrate capable of realizing miniaturization and high performance, and a manufacturing method thereof.

  In order to achieve the above object, the green sheet of the present invention is a glass ceramic green sheet comprising at least a ceramic powder, a glass ceramic powder containing glass powder, and an organic binder, wherein the glass ceramic powder is the glass. It is characterized by being a powder that has been heat-treated at a temperature above the glass transition temperature of the powder and below the softening point.

  Since the green sheet of the present invention can secure low-temperature sinterability while having high air permeability, it has good conductivity while suppressing the stacking failure and short-circuit failure of the glass ceramic multilayer substrate represented by the LTCC substrate. There is an effect that low-temperature simultaneous firing with the conductor can be realized.

  Moreover, the multilayer substrate using this green sheet has the effect of being able to achieve downsizing and high performance.

  The green sheet of the present invention and the multilayer substrate using the same are characterized by glass ceramic powder which is a component constituting the green sheet.

  The first invention of the present invention is a glass ceramic green sheet comprising at least a ceramic powder, a glass ceramic powder containing a glass powder, and an organic binder, wherein the glass ceramic powder has a glass transition temperature of the glass powder. It is a powder that has been heat-treated at a temperature lower than the softening point as described above, thereby suppressing poor lamination and short-circuiting of the multilayer substrate, and simultaneously with a conductor having good conductivity at low temperature. It has the effect that firing can be realized.

  According to a second aspect of the present invention, the specific surface area of the glass ceramic powder after heat treatment is 30% or more and less than 60% of the specific surface area of the glass ceramic powder before heat treatment. This has the effect of being able to achieve both the laminateability of the green sheet and the good sinterability of the glass ceramic powder.

  According to a third aspect of the present invention, the air resistance (Gurley) is 5 × t (sec) or less when the thickness of the green sheet is t μm, whereby the green sheet and the electrode are alternately arranged. It has the effect of being effective in suppressing stacking faults at the time of stacking and suppressing short circuit defects due to bleeding of the electrode paste when the electrode paste is formed on a green sheet by screen printing.

  According to a fourth aspect of the present invention, in the glass ceramic powder, the ceramic powder includes a ceramic powder having a tungsten bronze structure including Ba, Ti, and O and at least Nd or Sm. The body contains at least Si, Ba, La and O, and the glass ceramic produced by firing the glass ceramic powder has a high dielectric constant and good high frequency characteristics. This has the effect of realizing higher performance and higher performance.

  According to a fifth aspect of the present invention, a laminate in which a plurality of the green sheets according to any one of claims 1 to 4 are laminated is fired at a firing temperature of 900 ° C. to 950 ° C., and the relative density is 95%. Thus, the green sheet and the conductor containing Ag as a main component can be fired simultaneously, and the strength and reliability as a multilayer substrate can be improved. .

  In addition, when laminating using the green sheet of the present invention, an adhesive layer that has been conventionally required is unnecessary, so that there is an effect that delamination caused by the adhesive layer is not generated. That is, since the green sheet of the present invention is excellent in air permeability, an adhesive layer is not necessary when it is laminated. Therefore, delamination caused by the adhesive layer does not occur, and the reliability as a multilayer substrate can be improved.

  Further, since the adhesive layer is unnecessary, there is an effect that the cost can be reduced accordingly.

  A sixth invention of the present invention includes a step of heat-treating at least a glass ceramic powder containing a ceramic powder and a glass powder at a temperature not lower than the glass transition temperature of the glass powder and lower than the softening point; A step of producing a slurry containing the glass ceramic powder, an organic binder and a dispersion medium, a step of forming and drying the produced slurry into a film to obtain a green sheet, and a conductor containing Ag or Cu as a main component A step of forming a layer, a step of alternately laminating the green sheet and a conductor layer mainly composed of Ag or Cu, and obtaining a laminate, and a step of firing the laminate. Thus, a multilayer substrate capable of realizing miniaturization and high performance can be easily manufactured.

  Hereinafter, a green sheet of the present invention, a multilayer substrate using the green sheet, and a method for manufacturing the same according to an embodiment and the drawings will be described taking a glass ceramic multilayer substrate with a built-in capacitor and coil as an example.

  1 and 2 are cross-sectional views for explaining a method of manufacturing a glass ceramic multilayer substrate in one embodiment of the present invention.

  First, in order to produce a green sheet as a glass ceramic dielectric layer, a predetermined amount of ceramic powder having an average particle diameter of 0.05 to 10 μm and glass powder are blended as a main component to obtain a glass ceramic powder. . Further, 50 to 300% by weight of water is blended with 100% by weight of the glass ceramic powder, and ball mill mixing is performed for 12 to 72 hours using 1 to 5 mmφ zirconia as a dispersion medium. The slurry consisting of is removed from the ball mill and dried. The dried glass ceramic powder is heat treated.

  Next, with respect to 100% by weight of the glass ceramic powder after drying, 4 to 15% by weight of a resin binder such as PVB, 40 to 120% by weight of a dispersion medium such as ester or alcohol, DBP (dibutyl phthalate), 2-12% by weight of plasticizer such as BBP (benzyl butyl phthalate), and if necessary, a small amount of a dispersant and an antifoaming agent are blended, and ball mill dispersion using 10 mmφ zirconia is conducted for 12 to 72 hours to produce a slurry. To do.

  Next, the obtained slurry is applied to a predetermined thickness on a carrier film such as a PET film which has been subjected to a mold release treatment by a sheet molding machine such as a die coating apparatus, and then dried in a drying furnace, and then FIG. A green sheet 101 which is a glass ceramic dielectric layer shown in FIG.

  Next, the green sheet 101 is punched at a predetermined position by punching or laser processing as necessary, and then drilled using a conductive paste mainly composed of Ag by screen printing or the like. The via electrode 102 is formed by filling the via hole. Thereafter, the wiring electrode 103 having the designed circuit pattern is formed on the green sheet 101 by a screen printing method using a conductive paste mainly composed of Ag.

  Next, the green sheets 101 each having printed wiring electrodes 103 are stacked and pressed while being aligned so as to have a predetermined design as shown in FIG. A laminated body 104 in which glass ceramic dielectric layers and electrode layers are alternately laminated as shown is formed. The size of the laminate 104 is usually 50 to 200 mm □, and the laminate 104 can produce a number of predetermined multilayer substrates 203 in a matrix.

  Further, a capacitor can be incorporated by disposing the wiring electrode 103 having a predetermined area on the inner layer portion of the laminate 104 so as to face each other with the green sheet 101 therebetween. Further, by stacking the wiring electrodes 103, it is possible to incorporate a capacitor having a larger capacity. It is also possible to incorporate a spiral coil through the via electrode 102 in which the wiring electrode 103 is formed on the green sheet 101. By incorporating these capacitors and coils, a glass ceramic multilayer substrate 203 capable of high-density mounting can be realized.

Next, the surface layer electrode 106 is formed on the laminate 104 using a conductive paste containing Ag as a main component. Thereafter, the laminated body 104 is pressurized at a predetermined pressure in the vertical direction of the laminated body 104, and the laminated body 104 is laminated and pressure-bonded. In addition, it is preferable that the temperature at the time of this lamination | stacking and pressurization is normal temperature-100 degreeC, and pressure is 20-1000 kgf / cm < ² >.

  Thereafter, the surface electrode 106 is formed on the laminated body 104 that has been laminated and pressure-bonded, and is cut into pieces, and the separated laminated body 104 is subjected to binder removal treatment at a temperature of 400 to 600 ° C.

  Next, as a firing step, firing is performed in an atmospheric atmosphere or a reducing atmosphere at a maximum holding temperature of 860 to 960 ° C., a holding time at the maximum temperature of 0.5 to 30 hours.

  Finally, as shown in FIG. 2, external electrodes 201 are formed on both end faces, and if necessary, plating on the external electrodes 201, mounting of surface parts 202, etc. are performed to obtain a glass ceramic multilayer substrate 203.

  Here, FIG. 3 and FIG. 13 schematically show changes in the morphology of the glass ceramic powder and the ceramic powder when heat treatment is performed after mixing and drying, respectively. FIG. 4 shows the shrinkage behavior of the corresponding glass ceramic powder.

  First, in the case where heat treatment is not performed or the heat treatment temperature is lower than the glass transition temperature of the glass powder 302 in the glass ceramic powder, the ceramic powder 301 and the glass powder 302 are as shown in FIG. Each is uniformly mixed. In this state, as shown in FIG. 4A, the dimensional shrinkage is almost zero, and no shrinkage occurs.

  On the other hand, when the heat treatment temperature is equal to or higher than the glass transition temperature of the glass powder 302, the diffusion of the glass powder 302 starts as shown in FIG. The glass powder 302 behaves elastically at a temperature lower than the glass transition temperature (Tg), but has a viscoelastic behavior at a temperature higher than the glass transition temperature (Tg), and the modulus of elasticity suddenly increases at the glass transition temperature. Decrease. For this reason, the mobility of the glass powder 302 increases and it adheres to the adjacent ceramic powder 301. A large number of gaps 303 can exist between the glass powder 302 and the ceramic powder 301 that are bonded together. For this reason, it becomes possible to reduce the density of the green sheet and increase the air permeability, suppress the stacking failure when the green sheet and the electrode are stacked alternately, and screen print the electrode paste on the green sheet. This is effective in suppressing bleeding of the electrode paste during formation. Further, regarding sinterability, if the glass powders 302 or the ceramic powders 301 adhere to each other to cause necking and increase the particle size, the sinterability is significantly reduced. On the other hand, when different types of powder such as glass powder 302 and ceramic powder 301 are bonded to each other, the particle size of each powder does not increase, so that the sinterability is not hindered. For this reason, the sinterability of the glass ceramic powder heat-treated in the above temperature range is ensured, and it is possible to achieve both a reduction in green sheet density and an increase in air permeability and a securing of the sinterability of the glass ceramic powder. In this state, dimensional shrinkage starts as shown in FIG. 4A, but the rate of change of dimensional shrinkage with respect to the heat treatment temperature is small.

  When the heat treatment temperature is higher than the softening point of the glass powder 302, the viscosity of the glass powder 302 decreases. Since the diameter increases and the sintering of the ceramic powder starts at the same time, the particle diameter of the ceramic powder 301 also starts to increase. For this reason, the sinterability of the glass-ceramic powder heat-processed in the said temperature range is inhibited remarkably. In this state, as shown in FIG. 4A, the rate of change in dimensional shrinkage with respect to the heat treatment temperature is rapidly increased.

  It is assumed that the necking start temperature of the ceramic powder alone is sufficiently higher than the necking start temperature of the glass powder alone, but usually the ceramic powder has a necking start temperature sufficiently higher than the glass powder. Is almost.

  FIG. 13 shows a change in the form when the conventional ceramic powder 1101 is heat-treated. Since the particle size increases when the heat treatment is performed under the condition that the ceramic powders 1101 adhere to each other, the driving force for sintering is shown. Decrease. Moreover, as shown in FIG.4 (b), since the glass powder is not contained, since a rapid dimensional change occurs near the firing temperature, the difference from the glass ceramic powder can be known.

  The specific surface area of the glass ceramic powder after the heat treatment is preferably 30% or more and less than 60% of the specific surface area of the ceramic powder before the heat treatment. When it is 60% or more, the porosity of the glass ceramic powder is small, so the green sheet is not good in lamination. Conversely, when it is less than 30%, the sintering of the ceramic powder starts and the particle size increases, so that the sinterability of the glass ceramic powder deteriorates.

Further, it is preferable that the air resistance (Gurley) is 5 × t (sec) or less when the thickness of the green sheet is t μm. Even if powder with a large specific surface area is used, the air permeability resistance is 5 × t (sec) or less, thereby suppressing the stacking failure when the green sheet and the electrode are alternately stacked, and the electrode paste on the green sheet. It is effective in suppressing short-circuit defects caused by bleeding of the electrode paste when formed by screen printing. The air resistance (Gurley) indicates the time required for 100 ml of air to pass through paper or paperboard having an area of 642 mm ² , and the larger the value, the more difficult the air passes. There is no clear definition of air permeability, but the larger the value, the easier air passes.

  A multilayer substrate obtained by laminating a plurality of the green sheets and firing at a firing temperature in the range of 900 ° C. to 950 ° C. has a relative density of 95% or more, and simultaneously fires the green sheet and a conductor mainly composed of Ag. Is preferably possible. When the glass ceramic powder is co-fired as a LTCC (low temperature co-fired ceramics) material with a conductor having a low melting point, the deterioration of the sinterability of the glass ceramic powder can be fatal. This green sheet that does not obstruct is effective.

  Hereinafter, the present invention will be described specifically by way of examples.

Example 1
Hereinafter, Example 1 in the manufacturing method of the green sheet of this invention and a multilayer substrate is demonstrated.

First, BaCO ₃ , Nd ₂ O ₃ , and TiO ₂ are prepared as main components to produce a green sheet that is a glass ceramic dielectric layer, and BaO: Nd ₂ O ₃ : TiO ₂ = 2: 2: 9. The ceramic powder having a composition (mol ratio) was calcined at 1500 ° C. to obtain a ceramic powder (BNT powder) having a tungsten bronze structure.

Next, at least SiO ₂ , BaCO ₃ , La ₂ O ₃ , and Al ₂ O ₃ were blended in predetermined amounts, and melted, quenched, and pulverized at 1400 ° C. to obtain glass powder. When the glass transition temperature (Tg) and softening point (Ts) of this glass powder were measured by the transition temperature measurement method by JIS R3103-3 thermal expansion method and the measurement method of JIS R3103-1 softening point, Tg was 680 ° C., Ts was 820 ° C.

  Further, 80% by weight of BNT powder, 20% by weight of glass powder, and other predetermined amounts of ceramic powder that plays a role as a sintering aid were blended to obtain glass ceramic powder. Further, after 100% by weight of water was added to 100% by weight of the glass ceramic powder, and ball mill mixing was performed for 1, 2, 24, 48, 72, and 128 hours using 2 mmφ zirconia as a dispersion medium. The slurry made of glass ceramic powder was taken out from the ball mill and dried to obtain six types of glass ceramic powder. Samples obtained by pulverizing these glass ceramic powders for 128 hours were sample No. No. 1 for 72 hours. No. 2 for 48 hours. No. 3 and 24 hr. No. 4 or 6 hrs ground. No. 5 and 1 hr. It was set to 6.

  The dried glass ceramic powder No. 3 was used for heat treatment. The heat treatment conditions were as follows: temperature increase / decrease rate of 300 ° C./hr, holding temperatures of 500, 600, 650, 680, 700, 750, 800, 820, 850, and 900 ° C., and a holding time of 2 hours. These glass ceramic powders heat-treated at 500 ° C. were sample Nos. No. 7, heat treated at 600 ° C. No. 8, heat treated at 650 ° C. No. 9, heat treated at 680 ° C. No. 10 and heat treated at 700 ° C. No. 11, 750 ° C. heat-treated. No. 12, heat treated at 800 ° C. No. 13 and 820 ° C. heat treated. No. 14 and heat treated at 850 ° C. No. 15 and heat treated at 900 ° C. It was set to 16.

  About each sample, the specific surface area was measured by the measuring method of the specific surface area by the gas adsorption BET method of JIS R1626 fine ceramic powder. The glass ceramic powder was also observed with a scanning electron microscope (SEM).

  Next, No. after drying. 1 to 16 glass ceramic powders of 100% by weight are blended with 8 parts by weight of PVB resin as an organic binder, 80% by weight of butanol as a dispersion medium, and 5% by weight of DBP (dibutyl phthalate) as a plasticizer. Ball mill dispersion using zirconia was performed for 48 hr to prepare a slurry.

  Next, the obtained slurry is applied to a predetermined thickness on a PET film that has been subjected to release treatment by a doctor blade type molding machine, and then dried in a drying furnace to produce a green sheet that is a glass ceramic dielectric layer. did. The thickness of the green sheet was controlled to be 40 μm. The density and air permeability of the green sheet were measured. The density was calculated by measuring the weight and thickness of a green sheet cut into a predetermined size. The air permeability was measured by JIS P8117 paper and paperboard-air permeability test method-Gurley tester method.

  Using this green sheet, 50 elements of the glass-ceramic multilayer substrate 203 described in FIG. 2 in one embodiment were produced. First, the printability of the conductor layer was evaluated. Since the line / space width of the narrowest conductor layer in the wiring pattern was 20 μm / 20 μm, the formation degree of the conductor after the conductor paste was screen-printed on the green sheet for the part considered to have the most severe printability was measured with a microscope. And the presence or absence of short-circuit due to bleeding was examined. Next, the presence or absence of stacking faults was evaluated. Since the thickness of the thickest conductor layer among the conductor layers was 40 μm, the presence or absence of defects when visually laminating at 60 ° C. was visually evaluated for the above portions considered to have the most severe lamination properties. The case where adhesion was good was marked with ◯, and the time when delamination occurred was marked with ×. The produced laminate was fired as a firing step under a low oxygen partial pressure at a maximum holding temperature of 900 ° C., a holding time of 2 hours at the maximum temperature. An external electrode was formed on the surface of the fired sample, plating on the external electrode, and surface component mounting were performed to obtain a glass ceramic multilayer substrate.

  Moreover, the sinterability of the green sheet was evaluated separately from the laminate. First, 50 green sheets were laminated, cut into a 1 mmφ disk shape, and then fired under binder removal and low oxygen partial pressure. The temperature increasing / decreasing rate was 300 ° C./hr, the maximum temperatures were 900 and 950 ° C., and the holding time at the maximum temperature was 2 h. The density was measured by the Archimedes method, the relative density was calculated, and the sinterability was evaluated. A case where the relative density at a firing temperature of 900 and 950 ° C. was 95% or more was evaluated as ◯, and a case where at least one of them was 95% or less was evaluated as ×.

  First, Table 1 and Table 2 show the results when the pulverization time was changed with the non-heat treated powder.

  As shown in (Table 1) and (Table 2), Sample No. As for 1-4, although the sinterability of the green sheet was good, the air permeability resistance increased (air permeability deteriorated), resulting in frequent stacking faults and short circuit faults when producing a multilayer substrate. On the contrary, the sample No. As for 5 and 6, the green sheet has low air permeability resistance (air permeability is good), and it was possible to produce a laminate having no lamination failure or short circuit failure. Since the properties are not sufficient, the strength of the fired multilayer substrate is not sufficient, and when the external electrode is plated, the plating solution penetrates and the high frequency characteristics deteriorate. In FIG. 3 and no. 5 shows an SEM photograph of the glass ceramic powder No. 5 having a large specific surface area. No. 5 powder no. It can be seen from the above picture that it is larger than 3.

Next, glass ceramic powder No. 1 having a specific surface area of 10.2 (m ² / g). No. 3 was heat treated powder No. 3 The results of 7 to 16 are shown in (Table 3) and (Table 4).

  Sample No. with a heat treatment temperature of less than 680 ° C., which is the glass transition temperature (Tg) of the glass powder. In Nos. 7 to 9, although the green sheet has good sinterability, the green sheet density is high and the air permeability resistance is high (air permeability is poor). Occurred frequently. On the contrary, the sample heat treatment temperature was 820 ° C. or higher which is the softening point (Ts) of the glass powder. As for Nos. 14 to 16, although the green sheet density was low and the air permeability resistance was low (air permeability was good), it was possible to produce a laminate with no lamination failure or short circuit failure. Body sample No. Similar to 5 and 6, the green sheet is not sufficiently sinterable, so the fired multilayer substrate is not strong enough, and the plating solution penetrates when the external electrode is plated, resulting in deterioration of high frequency characteristics. There has occurred. On the other hand, the heat treatment temperature of sample No. For Nos. 10 to 13, green sheet density and air permeability resistance can be lowered (good air permeability) while ensuring green sheet sinterability. Could be suppressed. In FIG. 5 and no. 12 shows an SEM photograph of No. 12 glass ceramic powder. 5 and no. Despite the fact that the specific surface area of No. 12 is the same, the particle size of the powder is clearly no. 12 looks smaller. This is presumably because different powder sizes of ceramic powder and glass powder are bonded to each other and the particle size of each powder does not increase.

  These series of results will be described in detail with reference to FIGS. FIG. 5 shows the percentage of the specific surface area of the glass ceramic powder after the heat treatment based on the specific surface area of the glass ceramic powder (No. 3) before the heat treatment. The heat treatment temperatures are 650 ° C. and 680 ° C. It can be seen that the value changes abruptly. This is due to the fact that the glass powder adheres to the ceramic powder. Corresponding to this value, as shown in FIG. 6, it can be seen that the value of the air permeability resistance is rapidly decreased (that is, the air permeability is good) and is 60% or less. However, as shown in FIG. 6, the relative density of the sintered body obtained by firing the green sheet at 900 ° C. hardly changed between the heat treatment temperatures of 650 ° C. and 680 ° C., and good sinterability was maintained. Next, as shown in FIG. 5, it is understood that the ratio of the specific surface area of the glass ceramic powder after the heat treatment with respect to that before the heat treatment is 800 ° C. and 820 ° C. and is less than 30%. This is due to the fact that the flowability of the glass powder is increased and the glass powder is adhered to each other. Corresponding to this value, as shown in FIG. 6, the value of air permeability resistance continued to decrease (air permeability became good), but the relative density was most affected. Since the particle size of the glass powder increased and sintering of the entire glass ceramic powder began, the driving force for sintering decreased significantly. FIG. 7 is a plot of the relationship between the air resistance and the relative density of the non-heat treated powder and the heat treated powder. This shows that there is a correlation (trade-off relationship) between the green sheet air resistance and the relative density of the non-heat treated powder, whereas the heat treatment powder has a heat treatment at 680 ° C to 820 ° C. A significant deviation from the relationship was observed. From these facts, it is possible to achieve both good air permeability and low temperature sinterability by heat-treating the glass ceramic powder at a temperature above the glass transition temperature of the glass powder and below the softening point. I have confirmed that I have it.

  In the present embodiment, the glass ceramic multilayer substrate with a built-in capacitor and coil has been described. However, the green sheet of the present invention and the multilayer substrate using the same are not limited thereto. For example, It can also be used for bandpass filters, antenna switch filters, power amplifier module substrates, and the like.

  The green sheet according to the present invention and the multilayer substrate using the same have the effect of ensuring both good air permeability and low-temperature sinterability as compared with conventional green sheets. It is useful for various multilayer ceramic electronic components that require higher performance.

(A), (b) is sectional drawing which respectively shows the manufacturing process of the multilayer substrate in one embodiment of this invention Sectional drawing for demonstrating the multilayer substrate in one embodiment of this invention (A)-(c) is a schematic cross section for demonstrating the glass ceramic powder in one embodiment of this invention, respectively. (A), (b) is the figure which showed the relationship between the heat processing temperature of glass ceramic powder and ceramic powder, and a dimensional shrinkage, respectively. The figure which showed the relationship between the heat processing temperature in Example 1 of this invention, and the ratio of the powder specific surface area after heat processing with respect to before heat processing. The figure which showed the air resistance of the green sheet in Example 1 of this invention, and the relative density of the sintered compact at the time of 900 degreeC baking The figure which showed the heat processing temperature in Example 1 of this invention, the air resistance of a green sheet, and the relative density of the sintered compact at the time of 900 degreeC baking (A)-(c) is the figure which showed the SEM photograph of the glass ceramic powder in Example 1 of this invention, respectively. (A)-(c) is sectional drawing which shows the manufacturing process of the conventional multilayer substrate all Cross-sectional view of a laminate with delamination (A)-(c) are process sectional drawings for demonstrating the mechanism in which delamination all generate | occur | produces (A)-(c) are all schematic cross sections of electrode shapes (A), (b) is a schematic sectional view for explaining a conventional ceramic powder, respectively

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 Green sheet 102 Via electrode 103 Wiring electrode 104 Laminated body 106 Surface electrode 201 External electrode 202 Surface component 203 Multilayer substrate 301 Ceramic powder 302 Glass powder 303 Void

Claims (6)

In a glass ceramic green sheet containing at least a ceramic powder, a glass ceramic powder containing glass powder, and an organic binder, the glass ceramic powder is at a temperature not lower than the glass transition temperature of the glass powder and lower than the softening point. A green sheet characterized by being a heat-treated powder. The green sheet according to claim 1, wherein the specific surface area of the glass ceramic powder after heat treatment is 30% or more and less than 60% of the specific surface area of the glass ceramic powder before heat treatment. The green sheet according to claim 2, wherein the air resistance (Gurley) is 5 × t (sec) or less when the thickness of the green sheet is t μm. In the glass ceramic powder, the ceramic powder includes a ceramic powder having a tungsten bronze structure including Ba, Ti, and O and at least Nd or Sm. The glass powder includes Si, Ba, La, and The green sheet according to claim 1, comprising at least O. A multilayer substrate in which a laminate in which a plurality of the green sheets according to any one of claims 1 to 4 are laminated is baked in a range of 900 ° C to 950 ° C to have a relative density of 95% or more. A step of heat-treating glass ceramic powder containing at least ceramic powder and glass powder at a temperature not lower than the glass transition temperature of the glass powder and lower than the softening point, and the heat-treated glass ceramic powder and organic binder. A step of producing a slurry containing a dispersion medium, a step of forming and drying the produced slurry into a film to obtain a green sheet, a step of forming a conductor layer mainly composed of Ag or Cu, and the green sheet And a conductor layer mainly composed of Ag or Cu, and a step of obtaining a laminate, and a step of firing the laminate.