JP2011238907A - Ceramic substrate and manufacturing method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a ceramic substrate which reduces deformation when a compact of a glass-ceramic composite is sintered, improves the dimensional accuracy of a substrate, reduces raw material costs and ensures a degree of freedom in design.SOLUTION: A ceramic substrate 1 comprises: a substrate body 2 which is obtained by sintering a compact of a glass-ceramic composite that includes glass powder and a ceramic filler; and a sintered layer 6 which is formed on a surface or an inner layer of the substrate body 2 and is obtained by sintering metallic paste having a sintering temperature lower than that of the glass-ceramic composite.

Description

  The present invention relates to a ceramic substrate and a method for manufacturing the same, and more particularly, to a ceramic substrate with little deformation during firing and excellent dimensional accuracy, and a method for manufacturing the same.

  Conventionally, in order to mount a semiconductor element such as a semiconductor circuit element or an electronic component such as a piezoelectric element or a solid-state imaging element (so-called CCD), a ceramic substrate having a built-in conductor layer constituting a wiring or the like has been used. In recent years, further improvement in the dimensional accuracy of ceramic substrates has been demanded as conductors have become thinner and parts have become smaller.

  In general, a ceramic substrate is made by adding a green binder by adding an organic binder, a plasticizer, etc. to a glass ceramic low-temperature sintered material, and printing a conductive paste on the surface of the ceramic sheet. It is produced by firing after integration by pressure bonding. However, due to the difference in thermal shrinkage between the green sheet and the conductor pattern, there is a problem that the green sheet laminate is deformed during firing due to the effect of the conductor pattern formation position on the entire green sheet and the opening area of the substrate. is there.

When manufacturing a ceramic substrate, for example, as shown in FIG. 1, a region (hereinafter, referred to as a connected wiring substrate) 3 that is a product portion in which a plurality of wiring substrate regions 5 are arranged in a vertical and horizontal direction has a large area. A plurality of green sheet laminates 2 are integrally formed.
In FIG. 1, there is a large difference in the installation density of the conductor pattern between the connection wiring board 3 and the area 4 that is the other blank part, so that the blank part area 4 contracts more than the connection wiring board 3. And the whole connection wiring board 3 may deform | transform into a drum shape (refer FIG. 3).
When the connecting wiring substrate 3 is deformed, the dimensional accuracy of the ceramic substrate is lowered, and a mounting position shift or the like may occur in the process of mounting elements or the like on the substrate.

In order to solve such a problem, a conductor layer for preventing distortion of the substrate is formed with a certain width around the green sheet constituting the ceramic substrate, and a plurality of green sheets including the green sheet are formed. Has been proposed (see, for example, Patent Document 1).
However, in this method, in order to sufficiently obtain the effect of suppressing the shrinkage of the substrate, it is necessary to considerably increase the area ratio of the conductor layer with respect to the entire substrate, which increases design restrictions and further increases the raw material cost. there were.

On the other hand, a method has been proposed in which the shrinkage correction paste is applied to the surface of the green sheet constituting the intermediate layer of the green sheet laminate and baked to increase the effect of suppressing the shrinkage of the laminate during firing (for example, , See Patent Document 2).
However, if the shrinkage correction paste is applied to the inner layer of the laminate, the wiring installation area in the inner layer of the substrate is reduced, which increases design restrictions and the paste formed in the inner layer erodes the wiring circuit. There was a problem of doing. Furthermore, when the shrinkage rate correction paste is applied to a plurality of layers in the substrate, there is a problem that the amount of the shrinkage rate correction paste used for the entire substrate increases and the raw material cost increases.

JP-A-2-47869 JP 2005-244099 A

  The present invention has been made in order to solve the above-described problems. The glass ceramic composition is less deformed when sintered, and the dimensional accuracy of the substrate is increased, the raw material cost is low, and the design is free. The purpose is to provide a ceramic substrate with a sufficient degree of accuracy. Moreover, this invention aims at provision of the manufacturing method of the ceramic substrate which manufactures the said ceramic substrate.

  That is, the ceramic substrate of the present invention is formed on a substrate body formed by sintering a molded body of a glass ceramic composition containing glass powder and a ceramic filler, and on the surface or inner layer of the substrate body. And a fired layer formed by sintering a paste (including an alloy, the same shall apply hereinafter) having a sintering temperature lower than the sintering temperature.

  The ceramic substrate is preferably formed by integrally sintering the glass ceramic composition compact and the metal paste. Moreover, it is preferable that the temperature difference of the sintering temperature of the said glass ceramic composition and the sintering temperature of the said metal paste is 150 degreeC or more and 300 degrees C or less. The metal paste fired layer preferably has a thickness of 1% to 10% with respect to the thickness of the substrate body. The metal of the metal paste is preferably a metal or alloy selected from silver, silver palladium alloy or silver platinum alloy. The metal paste fired layer is preferably provided so as to be exposed on one main surface or both main surfaces of the substrate body.

  Also, the method for producing a ceramic substrate of the present invention includes a step of applying a metal paste having a sintering temperature lower than the sintering temperature of the green sheet to form a metal paste fired layer on the surface of at least one green sheet. And a step of laminating the green sheets and a step of firing the laminated green sheets.

  According to the present invention, by forming a fired layer of a metal paste that is sintered at a temperature lower than that of the glass ceramic composition, it is possible to suppress shrinkage of the formed body of the glass ceramic composition along with the sintering. A ceramic substrate with improved accuracy can be obtained. Further, according to the present invention, the area ratio of the metal paste fired layer with respect to the entire substrate can be reduced, and a ceramic substrate with a high degree of design freedom and a low raw material cost can be obtained.

It is a top view which shows an example of the ceramic substrate of this invention. It is a top view which expands and shows the area | region of the connection wiring board of FIG. It is a top view which shows the state after baking of the connection wiring board provided in the ceramic substrate which concerns on other embodiment. It is a top view which shows an example of the molded object of the glass ceramic composition of the ceramic substrate of this invention. It is a top view which shows an example of the molded object of the glass ceramic composition of the ceramic substrate of this invention.

Hereinafter, the present invention will be described in detail.
The ceramic substrate of the present invention is formed on a substrate body formed by sintering a molded body of a glass ceramic composition containing glass powder and a ceramic filler, and on the surface or inner layer of the substrate body. A sintered layer obtained by sintering a metal (including an alloy; the same shall apply hereinafter) paste having a sintering temperature lower than the sintering temperature.

According to the present invention, a metal paste that is sintered at a temperature lower than that of the glass ceramic composition is applied to the surface of a glass ceramic composition formed body (hereinafter simply referred to as a formed body) constituting the substrate body. Alternatively, by forming a sintered layer of an alloy, shrinkage and deformation of the molded body accompanying sintering can be suppressed with higher accuracy than before, and dimensional accuracy can be improved.
Moreover, the area ratio of the metal paste fired layer with respect to the substrate body can be reduced by suppressing shrinkage and deformation of the molded body with higher accuracy than before, and the amount of metal paste used can be reduced as compared with the conventional case.

FIG. 1 is a plan view showing an example of a ceramic substrate 1 of the present invention.
In FIG. 1, a ceramic substrate 1 has a substrate body 2 that mainly constitutes the substrate. The substrate body 2 is obtained by sintering a molded body 2A (see FIG. 4) of a glass ceramic composition containing glass powder and a ceramic filler. In the substrate body 2, a connection wiring board as a product region is provided. 3 are arranged vertically 3 pieces, 2 pieces horizontally, a total of 6 pieces, with a fixed interval.
In the substrate body 2, a region excluding the connection wiring substrate 3 is a blank region 4 and is formed integrally with each connection wiring substrate 3.

In the connection wiring board 3, wiring board areas 5 are formed vertically and horizontally (see FIG. 2), and although not shown, dividing grooves for dividing the wiring board areas 5 are formed vertically and horizontally. Has been. A plurality of wiring substrates 5 are formed by dividing the substrate along the dividing grooves.
Each wiring board 5 is provided with a cavity (not shown), and a chip such as a light emitting element is mounted in the cavity to constitute an electronic component such as a light emitting device.

On one main surface (illustrated surface) of the substrate main body 2, a metal paste fired layer 6 formed in a narrow and strip shape is provided so as to be exposed on the main surface.
The metal paste fired layer 6 is for suppressing the shrinkage of the molded body 2A during sintering, and is parallel to one side of the substrate body 2 from one side edge portion of the substrate body 2 to the opposite side edge. One is provided in each blank area 4 between the connection wiring boards 3.
The metal paste fired layer 6 in the present invention is made of a metal paste having a sintering temperature lower than the sintering temperature of the glass ceramic composition constituting the substrate body 2 as described above. With such a configuration, when the molded body 2A of the glass ceramic composition starts to be sintered, the metal paste fired layer 6 is formed, so that the molded body 2A contracts and deforms with the sintering. Can be suppressed early.

In FIG. 1, the metal paste fired layer 6 is provided so as to be parallel to the direction in which the connection wiring substrate 3 expands when the molded body 2 </ b> A is sintered. That is, the metal paste fired layer 6 shown in FIG. 1 is provided for the molded body 2A in which the connection wiring board 3 expands in the arrow direction (left-right direction) in the drawing (see FIGS. 1 and 3) during firing. It is. Providing the metal paste fired layer 6 in parallel with the direction in which the connection wiring board 3 expands is preferable because deformation of the connection wiring board 3 during firing can be effectively suppressed.
The direction in which the connection wiring board 3 expands during firing varies depending on the installation position of the wiring pattern in the molded body 2A, the positional relationship between the molded body 2A and the heat source, and FIG. 1 shows an example thereof. Is.

The temperature difference between the sintering temperature of the glass ceramic composition constituting the substrate body 2 and the sintering temperature of the metal paste is preferably 150 ° C. or higher and 300 ° C. or lower.
When the temperature difference between the sintering temperature of the glass ceramic composition and the sintering temperature of the metal paste is less than 150 ° C., the strength of the fired metal paste layer 6 when the molded body 2A of the glass ceramic composition is sintered ( There is a possibility that the degree of sintering) is too low and the shrinkage of the molded body 2A cannot be sufficiently suppressed.
On the other hand, when the temperature difference between the sintering temperature of the glass ceramic composition and the sintering temperature of the metal paste exceeds 300 ° C., the strength (sintering degree) of the metal paste fired layer 6 when the molded body 2A is sintered is increased. If it is too high, the molded body 2A around the metal paste fired layer 6 may be deformed during firing, which may make it difficult to control the sintered state of the molded body 2A.

  The metal paste constituting the metal paste fired layer 6 is, for example, a paste obtained by adding a vehicle such as ethyl cellulose to a metal powder such as silver, a silver palladium alloy or a silver platinum alloy, and a solvent, a sintering aid as required. Can be used. As the metal powder used for the metal paste, in particular, silver powder can be preferably used from the viewpoint of efficiently suppressing the shrinkage of the molded body 2A.

The 50% average particle diameter (D ₅₀ ) of the metal powder used for the metal paste is preferably 0.5 μm or more and 2.5 μm or less. If the particle size of the metal powder is less than 0.5 μm, the sintering proceeds excessively and the substrate body may be deformed. On the other hand, when the particle size of the metal powder exceeds 2.5 μm, the metal paste becomes difficult to sinter, and the metal paste layer 6a (the state before the metal paste layer 6 is fired is indicated as 6a, see FIG. 4). There is a possibility that the effect of improving the dimensional accuracy cannot be obtained sufficiently because the crystallization temperature becomes too high.
In the present specification, the 50% average particle diameter means a value measured by a particle diameter measuring apparatus using a laser diffraction / scattering method.

Moreover, when adding an additive to a metal paste, it is preferable that the addition amount is 5 mass% or less with respect to the whole metal paste.
If the amount of the additive added exceeds 5% by mass with respect to the entire metal paste, the sintering temperature of the metal paste becomes too high or too low, and the effect of improving the dimensional accuracy is sufficiently obtained. There is a risk of being lost.
As the additive added to the metal paste, glass frit for promoting the progress of sintering, metal oxide for delaying the progress of sintering, and the like are used. Note that glass frit and metal oxide can be used without any particular limitation.

The thickness of the metal paste fired layer 6 is preferably 1% or more and 10% or less with respect to the thickness of the substrate body 2. When the thickness of the metal paste fired layer 6 is less than 1% with respect to the thickness of the substrate body 2, the effect of suppressing the deformation of the molded body 2A may not be sufficiently obtained. On the other hand, when the thickness of the metal paste fired layer 6 exceeds 10% with respect to the thickness of the substrate main body 2, the thickness of the substrate main body 2 is deformed, which may reduce the flatness of the substrate. .
The thickness of the metal paste fired layer 6 is preferably 2% or more and 4% or less with respect to the substrate body 2.

The area ratio of the metal paste fired layer 6 is preferably 0.8% or more and 1.8% or less with respect to the area of the entire ceramic sheet.
If the area ratio of the metal paste fired layer 6 is less than 0.8%, shrinkage associated with the sintering of the molded body 2A may not be sufficiently suppressed.
On the other hand, if the area ratio of the metal paste fired layer 6 exceeds 1.8%, the area of the connection wiring board 3 becomes too narrow, and the production efficiency may be reduced.

The metal paste fired layer 6 is preferably provided not only on one main surface (illustrated surface) of the substrate body 2 but also on the other main surface.
However, when the metal paste fired layer 6 is provided on both main surfaces of the substrate body 2, a position where the metal paste fired layer 6 is provided on one main surface and a position where the metal paste fired layer 6 is provided on the other main surface. Therefore, the entire molded body 2A may be deformed during firing.
Therefore, when the metal paste fired layers 6 are provided on both main surfaces of the substrate body 2, for example, substantially the same from the end of the substrate body 2 so as to correspond to the installation positions of the metal paste fired layers 6 on each surface. It is preferable to provide the distance.

Further, the metal paste fired layer 6 is preferably provided so as to be exposed on the main surface of the substrate body 2 as shown in FIG. 1 from the viewpoint of efficiently suppressing shrinkage of the molded body 2A during sintering. .
The metal paste fired layer 6 provided exposed on the main surface of the substrate body 2 has an installation area approximately 20% smaller than the metal paste fired layer 6 formed on the intermediate layer of the substrate body 2 and has the same degree of shrinkage suppression effect. Obtainable.
However, the metal paste fired layer 6 is not necessarily provided so as to be exposed on the main surface of the substrate body 2, and the metal paste fired layer 6 is provided in an intermediate layer of the substrate body 2, that is, inside the substrate body 2. You may make it provide. Further, it may be provided both on the main surface of the substrate body 2 and inside the substrate body 2.

  Further, the metal paste fired layer 6 is not limited to the one provided on the substrate body 2 alone. For example, the glass paste fired layer 6 is obtained by firing a glass paste body obtained by adding a plasticizer or the like to the glass powder. It is also possible to provide a ligation.

  In the ceramic substrate described above, the large-sized substrate body 2 is formed by integrating the plurality of connection wiring substrates 3 and the blank area 4, and the metal paste fired layer 6 is provided in the blank area 4. For example, the connection wiring board 3 may be formed separately and the metal paste fired layer 6 may be provided in a region in the connection wiring board 3.

  The substrate body 2 is formed by sintering a molded body of a glass ceramic composition containing glass powder and a ceramic filler, and the type of the substrate body 2 is not particularly limited as long as it is a flat plate member. Low temperature co-fired ceramics (hereinafter referred to as LTCC), aluminum nitride, and the like are excellent in terms of thermal conductivity, heat dissipation, strength, manufacturing cost, and the like, and are preferably used.

  As described above, the ceramic substrate 1 of the present invention has been described with an example. However, the configuration can be appropriately changed as long as it is not contrary to the spirit of the present invention.

  When LTCC is adopted as the substrate body 2, the ceramic substrate 1 of the present invention can be manufactured as follows. In the following description, the members used for the manufacture will be described with the same reference numerals as those of the finished product except for some parts.

  First, a green sheet is formed. The green sheet is prepared by adding a binder, and if necessary, a plasticizer, a solvent, etc. to a glass ceramic composition containing a glass powder for a substrate body and a ceramic filler, and preparing a slurry by using a doctor blade method or the like. It can be manufactured by molding and drying.

  Although the glass powder for substrate main bodies is not necessarily limited, a glass transition point (Tg) of 550 ° C. or higher and 700 ° C. or lower is preferable. When the glass transition point (Tg) is less than 550 ° C., degreasing described later may be difficult. On the other hand, when the glass transition point (Tg) exceeds 700 ° C., the shrinkage start temperature becomes high and the dimensional accuracy may be lowered.

As such a glass powder for a substrate body, for example, SiO ₂ is 57 mol% to 65 mol%, B ₂ O ₃ is 13 mol% to 18 mol%, CaO is 9 mol% to 23 mol%, and Al ₂ O ₃ is 3 mol%. It is preferably 8 mol% or less and at least one selected from K ₂ O and Na ₂ O in total containing 0.5 mol% or more and 6 mol% or less.

The glass powder for a substrate body can be obtained by producing glass having the above glass composition by a melting method and pulverizing it by a dry pulverization method or a wet pulverization method.
In the case of the wet pulverization method, it is preferable to use water as a solvent. For the pulverization, for example, a pulverizer such as a roll mill, a ball mill, or a jet mill is used.

  In addition, the glass powder for substrate bodies is not necessarily limited to what consists only of the said component, It can also contain another component in the range with which various characteristics, such as a glass transition point, are satisfy | filled. When other components are contained, the total content is preferably 10 mol% or less.

The 50% particle size (D ₅₀ ) of the glass powder for substrate main body is preferably 0.5 μm or more and 2 μm or less. When the 50% particle size of the glass powder for substrate main body is less than 0.5 μm, the glass powder is likely to aggregate, making it difficult to handle and uniformly dispersing. On the other hand, when the 50% particle size of the glass powder exceeds 2 μm, the glass softening temperature may increase or the sintering may be insufficient. The adjustment of the particle size may be classified as necessary after pulverization, for example.
The 50% particle size is a value measured by a particle size measuring apparatus using a laser diffraction / scattering method.

As the ceramic filler, those conventionally used for the production of LTCC substrates can be used without particular limitation. For example, alumina powder, zirconia powder, or a mixture of alumina powder and zirconia powder can be suitably used. The 50% particle size (D ₅₀ ) of the ceramic filler is preferably, for example, from 0.5 μm to 4 μm.

  Mixing and mixing such glass powder for substrate main body and ceramic filler such that glass powder for substrate main body is 30 mass% to 50 mass% and ceramic filler is 50 mass% to 70 mass%, for example. Thus, a glass ceramic composition can be obtained. Moreover, a slurry can be obtained by adding a plasticizer, a solvent, etc. to this glass ceramic composition as needed.

  As the binder, for example, polyvinyl butyral, acrylic resin and the like can be suitably used. As the plasticizer, for example, dibutyl phthalate, dioctyl phthalate, butyl benzyl phthalate and the like can be used. As the solvent, aromatic or alcoholic organic solvents such as toluene, xylene and butanol can be used. Furthermore, it is possible to use a dispersant or a leveling agent.

A green sheet can be produced by forming this slurry into a sheet by a doctor blade method or the like and drying it.
The green sheet thus manufactured can be cut into a predetermined dimensional angle using a punching die or a punching machine, and at the same time, via holes for interlayer connection can be punched and formed at predetermined positions.

An unfired conductor pattern is formed by printing a conductive metal paste for a conductor pattern on the surface of the connection wiring board 3 region of the green sheet by a method such as screen printing. In addition, an unfired interlayer connection portion is formed by filling a conductive metal paste into the above-described interlayer connection via hole.
As the conductive metal paste used for the conductor pattern and the interlayer connection portion, for example, a metal powder mainly composed of copper, silver, gold or the like is added with a vehicle such as ethyl cellulose, and a solvent or the like is added to form a paste. Things are used.

Next, an unfired metal paste layer 6a is formed by printing a metal paste on the surface of the uppermost layer and the lowermost layer green sheet of the substrate body 2 at a position shown in FIG. 4 by a method such as screen printing. It should be noted that the green metal paste layer 6a is formed at substantially the same position (meaning that it is recognized as the same position on the visual level) in both green sheets.
As the metal paste, for example, a metal powder such as silver, a silver palladium alloy, or a silver platinum alloy may be used by adding a vehicle such as ethyl cellulose, and if necessary, adding a solvent, a sintering aid, and the like to a paste. it can.
At this time, for example, a glass paste layer may be formed by applying a paste obtained by adding a plasticizer or the like to glass powder on the unfired metal paste layer 6a by screen printing or the like. Is possible.

  The green sheet on which the unfired conductor pattern and the unfired metal paste layer 6a are formed is aligned and heated and pressed to form a green body 2A shown in FIG. To do. Next, the molded body 2A is degreased by decomposing and removing a binder such as a resin contained in the green sheet by holding the molded body 2A at a temperature of, for example, 500 ° C. or more and 600 ° C. or less for 1 hour or more and 10 hours or less. Then, the glass ceramic composition which comprises a green sheet is baked by hold | maintaining for 20 minutes or more and 60 minutes or less, for example at the temperature of 850 degreeC or more and 900 degrees C or less. By this firing, the conductive metal paste and the metal paste formed inside and on the front surface (front and back surfaces) of the glass ceramic substrate are simultaneously fired, and the ceramic substrate 1 having the metal paste fired layer 6 can be obtained.

  When the degreasing temperature is less than 500 ° C. or the degreasing time is less than 1 hour, the binder or the like may not be sufficiently removed. On the other hand, if the degreasing temperature is about 600 ° C. and the degreasing time is about 10 hours, the binder and the like can be sufficiently removed, and if it exceeds this, the productivity may be lowered.

In the case of firing, if the firing temperature is less than 850 ° C. and the firing time is less than 20 minutes, a dense product may not be obtained. On the other hand, if the firing temperature is about 900 ° C. and the firing time is about 60 minutes, a sufficiently dense product can be obtained, and if this is exceeded, productivity and the like may be reduced.
The firing is particularly preferably performed at a temperature of 860 ° C. or higher and 880 ° C. or lower. When a metal paste containing a metal powder containing silver as a main component is used for forming the metal paste fired layer 6, when the firing temperature exceeds 880 ° C., the metal paste is excessively softened to have a predetermined shape. May not be able to maintain.

  As mentioned above, although the manufacturing method of the ceramic substrate 1 of the present invention has been described with an example, each forming order and the like can be appropriately changed as long as the ceramic substrate 1 can be manufactured.

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

<Green sheet>
First, a green sheet for a substrate body was manufactured.
That is, the _{SiO 2 60.4mol%, B 2 O} 3 to 15.6mol%, _Al 2 _{O 3} to 6 mol%, CaO and 15 mol%, 1 mol% of _{K 2} O, the Na ₂ O such that 2 mol% The raw materials were blended and mixed. The raw material mixture was put in a platinum crucible and melted at 1600 ° C. for 60 minutes, and then the molten glass was poured out and cooled. This glass was pulverized for 40 hours by an alumina ball mill to produce a glass powder for a substrate body. Note that ethyl alcohol was used as a solvent for grinding.

  35% by mass of this glass powder, 40% by mass of alumina filler (manufactured by Showa Denko KK, trade name: AL-45H), and zirconia filler (manufactured by Daiichi Rare Element Chemical Industries, trade name: HSY-3F-J) A glass ceramic composition for a substrate body was produced by blending and mixing so as to be 25% by mass. 50 g of this ceramic composition for a glass substrate body, 15 g of an organic solvent (a mixture of toluene, xylene, 2-propanol and 2-butanol in a mass ratio of 4: 2: 2: 1), a plasticizer (di-2 phthalate) -Ethylhexyl) 2.5 g, polyvinyl butyral (trade name: PVK # 3000K) 5 g as a binder, and 0.5 g of a dispersant (Bick Chemie, trade name: BYK180) 0.5 g are mixed and mixed to form a slurry. Was prepared.

This slurry was applied onto a PET film by a doctor blade method and dried to produce a green sheet for a main body.
The green sheet thus manufactured was cut into 174 mm vertical and 170 mm horizontal squares using a punching die, and at the same time, via holes for interlayer connection were punched and formed at predetermined positions.

Silver powder (manufactured by Daiken Chemical Industry Co., Ltd., trade name: S400-2), ethyl cellulose as a vehicle is blended at a mass ratio of 85:15, and α-terpineol as a solvent is added so that the solid content is 82 mass%. After the dispersion, the mixture was kneaded for 1 hour in a porcelain mortar, and further dispersed three times with three rolls to produce a metal paste A.
Further, silver powder (manufactured by DOWA Electronics, trade name: AG-SAG113), ethyl cellulose as a vehicle and rhodium oxide as an additive are blended in a mass ratio of 86.9: 13: 0.1, and α as a solvent After being dispersed in terpineol, kneading was carried out for 1 hour in a porcelain mortar, and further, dispersion was carried out three times with three rolls to produce metal paste B.

  On the other hand, conductive powder (manufactured by Daiken Chemical Industry Co., Ltd., trade name: S550) and ethyl cellulose as a vehicle are blended at a mass ratio of 85:15, and α-terpineol as a solvent so that the solid content is 85 mass%. Then, kneading was carried out in a porcelain mortar for 1 hour, and further three times of dispersion with a three roll to produce a metal paste for through conductors.

Next, a glass ceramic composition used for the overcoat layer was produced. That is, raw materials were blended and mixed so that SiO ₂ was 81.6 mol%, B ₂ O ₃ was 16.6 mol%, and K ₂ O was 1.8 mol%, and this raw material mixture was placed in a platinum crucible at 1600 ° C. Then, the molten glass was poured out and cooled. This glass was pulverized with an alumina ball mill for 20 hours to produce a glass powder for a substrate body. Note that ethyl alcohol was used as a solvent for grinding. Next, an alumina filler (made by Showa Denko KK, trade name: AL-45H) having a 50% particle size (D ₅₀ ) of 2 μm is blended with the glass powder for overcoat layer so as to be 30% by mass. And the glass ceramic composition for overcoat layers was manufactured by mixing.

The above glass ceramic composition and the resin component are blended in a proportion of 60% by mass of the glass ceramic composition and 40% by mass of the resin component, kneaded in a porcelain mortar for 1 hour, and further 3 in three rolls. The glass paste for overcoat layer was produced by performing dispersion once.
As the resin component, ethyl cellulose and α-terpineol were prepared and dispersed at a mass ratio of 85:15.

A through hole having a diameter of 0.3 mm is formed in a portion corresponding to the unfired through conductor in the region 3 of the connection wiring board of the green sheet for the main body by using a hole puncher, and is filled with a conductive metal paste by a screen printing method. A through conductor paste layer was formed, and an unfired connection terminal conductor paste layer and an unfired external electrode terminal conductor paste layer were formed.
The green sheets were overlapped so that the thickness after firing was 1.0 mm and integrated by thermocompression bonding to obtain a green sheet 2A for a body with a conductive paste layer, that is, a molded body 2A.

  In addition, in the green sheet 2A for a body with a conductive paste layer, six rectangular regions each having a length of 44 mm and a width of 66 mm were formed to form a connection wiring board 3. Moreover, the area (width 14 mm) between each connection wiring board 3 and between the edge part of the main body green sheet 2 </ b> A to each connection wiring board 3 was defined as a blank area 4.

Example 1
The metal paste A is screen-printed so that the width of the dried and fired metal paste fired layer 6 is 1 mm in the blank areas 4 (see FIG. 4) on both the front and back surfaces of the green sheet 2 for the main body with the conductive paste layer. Coating was performed by a method to form an unfired metal paste layer 6a-1, and an unfired ceramic substrate 1A was manufactured.

(Examples 2 to 4)
In the production of the unfired ceramic substrate 1 of Example 1, the installation position of the unfired metal paste layer 6a, the width of the metal paste fired layer 6 and the type of the metal paste were changed as shown in Table 1, An unsintered ceramic substrate 1A having paste layers 6a-2 to 6a-3 was produced (Examples 2 to 3).
Further, in the production of the unfired ceramic substrate 1 of Example 1, the installation position of the unfired metal paste layer 6a, the width of the metal paste fired layer 6 and the type of the metal paste were changed as shown in Table 1, and the unfired A metal paste layer 6a-4 was formed, and further an overcoat layer glass paste was applied thereon to produce an unfired ceramic substrate 1A (Example 4).

(Comparative Example 1)
An unfired ceramic substrate 1A was produced in the same manner as in Example 1 except that the unfired metal paste layer 6a was not formed on any surface of the green sheet 2A for a body with a conductive paste layer (Comparative Example 1). ).

(Reference Example 1)
An unfired metal paste layer 6a-5 was formed by printing the metal paste B on both the front and back surfaces of the green sheet 2A for a body with a conductive paste layer so that the width of the dried and fired metal paste fired layer 6 was 2 mm. Except for this, an unfired ceramic substrate 1A was produced in the same manner as in Example 1 (Reference Example 1).

  The non-fired ceramic substrate 1A obtained above was degreased by holding at 550 ° C. for 5 hours, and further fired by holding at 870 ° C. for 30 minutes to produce a ceramic substrate 1. At this time, the sintering temperatures of the metal pastes used in Examples 1 to 4, Comparative Example 1, and Reference Example 1 were the temperatures shown in Table 1, respectively.

  Next, the deformation amount in each wiring board region was measured for each of the ceramic substrates 1 of Examples 1 to 4, Comparative Example 1, and Reference Example 1. Specifically, for the connection wiring board 3 after firing, the width of the central region (the width at position B in FIG. 1) and the width of the end region (the width at position A or C in FIG. 1) are measured. The difference was defined as the deformation amount (μm). The results are summarized in Table 1.

  As is apparent from Table 1, the ceramic substrates 1 of Examples 1 to 4 in which the metal paste fired layer 6 was formed using a metal paste sintered at a lower temperature than the substrate body 2 were obtained in each of the interconnected wiring boards 3 after firing. The difference between the width of the central region (position B in FIG. 1) and the width of the end region (position A or position C in FIG. 1) is suppressed to less than 0.1%, and the central region (position B in FIG. 1) It was confirmed that the shrinkage of the end region (A position or C position in FIG. 1) was suppressed.

(Example 5)
In the first to fourth embodiments described above, one unfired metal paste is provided in each blank area 4 between the connection wiring boards 3 from one side edge of the main body green sheet 2A to the opposite side edge. Layers 6a-1 to 6a-4 were provided to form an unfired ceramic substrate 1A.
On the other hand, in Example 5, as shown in FIG. 5, the metal paste A is screened so as to surround each connection wiring board 3 in the blank areas 4 on both the front and back surfaces of the green sheet 2A for the body with the conductive paste layer. An unfired ceramic substrate 1A having an unfired metal paste layer 6a-6 was produced in the same manner as in Example 1 except that it was applied by a printing method (Example 5).
The unfired ceramic substrate 1A thus obtained was degreased by holding at 550 ° C. for 5 hours, and further fired by holding at 870 ° C. for 30 minutes to produce a ceramic substrate 1. Under the present circumstances, the sintering temperature of the metal paste A used in Example 5 was 650 degreeC.

The amount of deformation in each wiring board region of the ceramic substrate 1 obtained in Example 5 was measured in the same manner as in Examples 1 to 4.
The amount of deformation of the ceramic substrate 1 of Example 5 is equivalent to the amount of deformation of the ceramic substrate 1 of Example 1, and the width of the central region (position B in FIG. 1) and the end region (position A or C in FIG. 1). Position) width difference is suppressed to less than 0.1%, there is almost no swelling of the central region (position B in FIG. 1), and shrinkage of the end region (position A or position C in FIG. 1) is suppressed. It was recognized that

DESCRIPTION OF SYMBOLS 1 ... Ceramic substrate, 1A ... Unbaked ceramic substrate, 2 ... Substrate body, 2A ... Molded body of glass ceramic composition, 3 ... Connection wiring board (product area), 4 ... Blank area, 5 ... Wiring board area, 6 ... Metal paste fired layer, 6a ... Metal paste layer

Claims (7)

A substrate body formed by sintering a molded body of a glass ceramic composition containing a glass powder and a ceramic filler;
A fired layer formed on the surface or inner layer of the substrate body and having a sintering temperature lower than the sintering temperature of the glass ceramic composition (including an alloy; the same shall apply hereinafter) paste. A ceramic substrate characterized by that.   The ceramic substrate according to claim 1, wherein the molded body of the glass ceramic composition and the metal paste are sintered together.   The ceramic substrate according to claim 1 or 2, wherein a temperature difference between a sintering temperature of the glass ceramic composition and a sintering temperature of the metal paste is 150 ° C or higher and 300 ° C or lower.   The ceramic substrate according to any one of claims 1 to 3, wherein the fired metal paste layer has a thickness of 1% to 10% with respect to a thickness of the substrate body.   The ceramic substrate according to any one of claims 1 to 4, wherein the metal of the metal paste is a metal or an alloy selected from silver, a silver palladium alloy, and a silver platinum alloy.   The ceramic substrate according to any one of claims 1 to 5, wherein the metal paste fired layer is provided so as to be exposed on one main surface or both main surfaces of the substrate body. Applying a metal paste having a sintering temperature lower than the sintering temperature of the green sheet on at least one green sheet surface to form a metal paste fired layer;
Laminating the green sheets;
Firing the laminated green sheets. A method for producing a ceramic substrate, comprising:

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