JP2006089352A - Glass ceramic multilayer wiring board with built-in dielectric paste and capacitor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a glass-ceramic multilayer wiring board with a built-in capacitor in which a dielectric constant of a dielectric layer has a small temperature change rate to some extent, has a high dielectric constant, and does not contain Pb.
A dielectric paste includes 85.0 to 99.5 parts by mass of a barium titanate powder and 0.5 to 15.0 parts by mass of a glass powder containing an alkali metal, as well as a resin binder and an organic material. Comprising a solvent.
[Selection] Figure 1

Description

  The present invention relates to a dielectric paste using barium titanate and a glass ceramic multilayer wiring board with a built-in capacitor.

  In recent years, in the semiconductor field that forms the core of the IT (Information Technology) industry, the performance of semiconductor devices such as ICs and LSIs has been remarkably improved, and the semiconductor devices are information processing devices represented by large computers, personal computers, mobile communication terminals, and the like. Supports high speed, downsizing, multi-functionality, etc. In order to increase the transmission speed of high-frequency signals input to and output from semiconductor elements, low-resistance conductors such as Ag and Cu are used as the conductor material, which can be fired at the same time and low-temperature sintering with low dielectric loss in the high-frequency band Multilayer substrates (glass ceramic multilayer wiring substrates) have been developed.

  In addition, a structure in which a large-capacitance capacitor is built in a glass ceramic multilayer wiring board on which a semiconductor chip is mounted has been proposed. By disposing the capacitor inside the glass ceramic multilayer wiring board closer to the semiconductor chip, the impedance of the power source affecting the semiconductor chip can be lowered, and the entire board can be downsized.

  With the reduction in size and weight of electronic devices and the high density mounting of electronic components, there is an increasing demand for downsizing and increasing the capacity of capacitors disposed inside glass ceramic multilayer wiring boards. In order to reduce the size and increase the capacity of the capacitor, it is necessary to make the dielectric layer thin or use a dielectric material having a high dielectric constant. Therefore, the dielectric material is required to have a high dielectric constant.

  Further, from the viewpoint of temperature stability of the glass-ceramic multilayer wiring board with a built-in capacitor, the dielectric layer of the capacitor formed inside is required to have a small temperature change rate of the dielectric constant.

One of dielectric materials having a high dielectric constant has a perovskite structure typified by barium titanate. The ceramic capacitor mainly composed of barium titanate is obtained by firing the dielectric layer and electrode layer mainly composed of barium titanate at 1250 ° C to 1350 ° C. At that time, the sintered body of barium titanate has a temperature change rate of the dielectric constant of the dielectric layer by controlling the crystal grain size to 0.3 μm to 0.8 μm with 50% grain size distribution in the number cumulative grain size distribution. Can be obtained to a certain extent and with a high dielectric constant.
JP 1995-320540 A JP-A-1996-306232 JP 2000-072477 A JP 2001-31469 A

  However, a glass-ceramic multilayer wiring board with a built-in capacitor is generally produced by forming a dielectric paste and a conductive paste on a glass-ceramic green sheet and simultaneously firing them at a temperature of 1000 ° C. or lower. Therefore, when the capacitor formed inside the glass ceramic multilayer wiring board is made of the above barium titanate, the firing temperature of the barium titanate is higher than the firing temperature of the glass ceramic. However, there are problems such as voids and the like in the interior, resulting in coarse and dense, a desired dielectric constant not being obtained, and substrate strength being lowered.

  Therefore, in order to solve this problem, when the glass ceramic green sheet and the dielectric paste are fired simultaneously, the dielectric paste becomes a liquid phase at a low temperature of 1000 ° C. or lower, and barium titanate is dissolved in the liquid phase. There has been proposed a method of mixing glass powder containing Pb having an effect of promoting the grain growth of barium titanate. However, a capacitor using glass powder containing Pb has a very large effect of dissolving barium titanate in the liquid phase, so that the particle size of barium titanate becomes excessively large, and the dielectric constant changes in temperature. There was a problem that the rate increased. Moreover, the glass containing Pb also has a problem that it has a high possibility of adversely affecting the human body and the environment.

  Therefore, as a method for enabling simultaneous firing of the glass ceramic green sheet and the dielectric paste without using Pb-containing glass, a large amount of glass is mixed as a sintering aid in the dielectric paste, and the glass ceramic green A method for matching the sintering temperature with the sheet has been proposed. However, in this case, the volume of the glass having a low dielectric constant increases and the dielectric constant of the dielectric layer becomes low, which makes it difficult to reduce the size and increase the capacity of the capacitor.

  The present invention has been completed in view of the above problems, and its object is to provide a glass ceramic with a built-in capacitor that has a relatively small temperature change rate of the dielectric constant of the dielectric layer, a high dielectric constant, and does not contain Pb. It is to provide a multilayer wiring board.

  The dielectric paste of the present invention includes 85.0 to 99.5 parts by mass of barium titanate powder and 0.5 to 15.0 parts by mass of glass powder containing an alkali metal, as well as a resin binder and an organic solvent. It is characterized by comprising.

  The dielectric paste of the present invention is preferably such that the barium titanate powder has a particle size of 50% in the number cumulative particle size distribution and less than 0.8 μm, and the glass powder contains Ca, Mg, Mn, It contains at least one of Zn, Nb, Co, Bi and Sn.

  The glass-ceramic multilayer wiring board with a built-in capacitor according to the present invention includes a dielectric layer made of barium titanate formed inside an insulating substrate made of glass ceramics, and Ag, A capacitor-embedded glass-ceramic multilayer wiring board comprising an electrode layer made of any one of Cu, Ag-Pt, Ag-Pd, and Cu-W, wherein the dielectric layer comprises 85. barium titanate. 0 to 99.5 parts by mass and 0.5 to 15.0 parts by mass of glass containing an alkali metal, and the crystal grain size of the barium titanate is 50% in the number cumulative particle size distribution. It is 0.3 μm to 0.8 μm.

  The capacitor built-in glass ceramic multilayer wiring board of the present invention is preferably characterized in that the dielectric layer contains at least one of Ca, Mg, Mn, Zn, Nb, Co, Bi and Sn. To do.

  The dielectric paste of the present invention contains 85.0 to 99.5 parts by mass of barium titanate powder and 0.5 to 15.0 parts by mass of glass powder containing an alkali metal. The contained glass becomes a liquid phase at a low temperature of 1000 ° C. or lower and dissolves barium titanate in the liquid phase, thereby having an effect of promoting the grain growth of barium titanate. Therefore, it is not necessary to add a large amount of glass as a sintering aid, and it becomes possible to sinter barium titanate at a low temperature of 1000 ° C. or less without using Pb-containing glass. You can get a body.

  In the dielectric paste of the present invention, the particle size of the barium titanate powder is preferably less than 0.8 μm at a 50% particle size in the number cumulative particle size distribution, and the glass powder contains Ca, Mg, Mn, Zn, Since these elements contain at least one of Nb, Co, Bi, and Sn, these elements suppress grain growth in the sintering process of barium titanate. The crystal grain size of barium titanate can be 0.3 μm to 0.8 μm with a 50% particle size in the number cumulative particle size distribution. As a result, the dielectric layer can be made of a tetragonal barium titanate having a high dielectric constant and a small temperature change rate, so that the particle size of the barium titanate is excessive by using Pb-added glass. A glass ceramic multilayer wiring board incorporating a capacitor with a high dielectric constant can be obtained without increasing the temperature change rate of the dielectric layer.

  In the glass-ceramic multilayer wiring board with a built-in capacitor according to the present invention, the electrode layer is made of any one of Ag, Cu, Ag-Pt, Ag-Pd, and Cu-W, and the number of crystal grains of the barium titanate in the dielectric layer is integrated. Since the 50% particle size in the particle size distribution is 0.3 μm to 0.8 μm, low resistance conductors such as Ag, Cu, Ag—Pt, Ag—Pd, and Cu—W can be used. Therefore, a glass ceramic multilayer wiring board having a built-in capacitor with a low dielectric constant and a high dielectric constant can be obtained.

  In the capacitor-embedded glass ceramic multilayer wiring board of the present invention, preferably, the dielectric layer contains at least one of Ca, Mg, Mn, Zn, Nb, Co, Bi, and Sn. The element suppresses grain growth during the sintering process of barium titanate. As a result, a dielectric layer having a 50% particle size distribution of 0.3 μm to 0.8 μm in the number cumulative particle size distribution, which is a crystal particle size of barium titanate having a low dielectric constant temperature change and a high dielectric constant. A glass ceramic multilayer wiring board having a built-in capacitor with a low dielectric constant and a high dielectric constant can be obtained easily.

  A dielectric paste and a capacitor-embedded glass ceramic multilayer wiring board (hereinafter also referred to as a substrate) according to the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a sectional view showing an example of an embodiment of a glass-ceramic multilayer wiring board with a built-in capacitor according to the present invention. In FIG. 1, 1 is a dielectric layer incorporated in a glass ceramic multilayer wiring board, 2 is an electrode layer, and 3 is an insulating substrate.

  The dielectric paste of the present invention includes 85.0 to 99.5 parts by mass of barium titanate powder and 0.5 to 15.0 parts by mass of glass powder containing an alkali metal, as well as a resin binder and an organic solvent. Comprising. When the glass powder is less than 0.5 parts by mass, it becomes difficult to sinter the dielectric layer 1 at 1000 ° C. or less, voids are generated inside, resulting in a coarse density, and a desired dielectric constant cannot be obtained. Strength decreases. On the other hand, when the glass powder exceeds 15.0 parts by mass, the volume of the glass having a low dielectric constant increases and the dielectric constant of the dielectric layer 1 decreases, making it difficult to reduce the size and increase the capacity of the capacitor. .

  The barium titanate powder is fired at the same time as the insulating layer made of the electrode layer and the glass ceramic at 1000 ° C. or less, so that the 50% particle size distribution in the number cumulative particle size distribution is 0.7 μm or less (less than 0.8 μm) It is preferable that the particles have a small particle size. When the 50% particle size distribution in the number cumulative particle size distribution of the barium titanate powder exceeds 0.7 μm (0.8 μm or more), it becomes difficult to sinter the dielectric layer at 1000 ° C. or less, and there are voids inside. As a result, a problem arises that the desired dielectric constant cannot be obtained or the substrate strength is reduced.

  The glass powder contains an alkali metal. A glass containing an alkali metal becomes a liquid phase at a low temperature of 1000 ° C. or less and has an effect of promoting liquid phase sintering of barium titanate by dissolving barium titanate in the liquid phase. Therefore, it is possible to sinter barium titanate at a low temperature of 1000 ° C. or lower without using a glass containing a large amount of glass.

  If the glass powder is a glass containing an alkali metal belonging to Group 1A of the periodic table, the liquid phase becomes a liquid phase at a low temperature of 1000 ° C. or lower, and barium titanate is dissolved in the liquid phase. In order to promote the sintering, a desired effect can be obtained. However, when the effect of the same amount is considered, the one having a smaller atomic radius has a larger action. Therefore, from the viewpoint of eliminating the need to add a large amount of glass, those having a small atomic radius such as Li and Na are preferable.

The glass powder can be obtained by melting and vitrifying a mixture of a network-forming oxide and network-modifying oxide constituting the glass and an alkali metal oxide. The addition amount of the alkali metal oxides depending on the type, for example, when adding Li ₂ O, it is preferable to add from 2.0 to 60.0 parts by weight per 100 parts by weight of glass component. When the addition amount is less than 2.0 parts by mass, it becomes difficult to obtain glass having a sufficient liquid phase state to sinter the dielectric layer 1 at 1000 ° C. or less, and voids or the like are generated inside, resulting in coarseness. The desired dielectric constant cannot be obtained or the substrate strength is lowered. On the other hand, when the addition amount exceeds 60.0 parts by mass, it becomes difficult to vitrify the mixed powder of the oxide, and it becomes difficult to use it as a sintering aid used for the dielectric paste.

As glass containing such an alkali metal, when the alkali metal is represented as M ³ , SiO ₂ —M ³ ₂ O, SiO ₂ —B ₂ O ₃ —M ³ ₂ O, SiO ₂ —B ₂ O ₃ -Al ₂ O ^₃ -M _{3 2} O systems.

  Further, the barium titanate powder has a 50% particle size distribution in the number cumulative particle size distribution of less than 0.8 μm, and among glass powders containing alkali metals, Ca, Mg, Mn, Zn, Nb, Co, Bi and Sn Those containing at least one of them are preferred. By containing at least one of Ca, Mg, Mn, Zn, Nb, Co, Bi, and Sn in the glass powder, these elements suppress grain growth during the sintering process of barium titanate. Accordingly, since the crystal grain size of barium titanate is 0.3 μm to 0.8 μm and becomes a tetragonal crystal, it is possible to obtain the dielectric layer 1 having a small dielectric constant temperature change rate and a high dielectric constant. it can.

Here, the particle size of the barium titanate powder is a 50% particle size in a number-integrated particle size distribution obtained by measurement by a microtrack method or the like. In addition, such _glass, SiO ₂ ^-M ₄ 2 O ^{_{based, SiO 2 -B 2 O 3 -M}} 4 2 O _{based, SiO 2 -B 2 O 3 -Al} 2 O 3 -M 4 2 O system (However, ^{M 4} represents Ca, Mg, Mn, or _{Zn), SiO 2 -Nb 2 O} 5 _{based, SiO 2 -B 2 O 3 -Nb} 2 O 5 _{based, SiO 2 -B 2 O 3 -Al} 2 O ₃ —Nb ₂ O ₅ system, SiO ₂ —Co ₃ O ₄ system, SiO ₂ —B ₂ O ₃ —Co ₃ O ₄ system, SiO ₂ —B ₂ O ₃ —Al ₂ O ₃ —Co ₃ O ₄ system SiO ₂ —Bi ₂ O ₃ system, SiO ₂ —B ₂ O ₃ —Bi ₂ O ₃ system, SiO ₂ —B ₂ O ₃ —Al ₂ O ₃ —Bi ₂ O ₃ system, SiO ₂ —SnO ₂ system, SiO ₂ -B ₂ O ₃ -SnO _{2 based, SiO 2 -B 2 O 3 -Al} 2 O 3 -Sn ₂ system, and the like.

  The resin binder and the organic solvent used for the dielectric paste are not particularly limited as long as they can be simultaneously fired with a glass ceramic green sheet (hereinafter also referred to as a green sheet) serving as the insulating substrate 3. The same resin binder and organic solvent blended in the sheet can be used. Examples of the resin binder include acrylic (a homopolymer or copolymer of acrylic acid, methacrylic acid or esters thereof, specifically, an acrylic ester copolymer, a methacrylic ester copolymer, an acrylic ester- Methacrylic acid ester copolymer, etc.), polyvinyl butyral, polyvinyl alcohol, acrylic-styrene, polypropylene carbonate, cellulose, and other homopolymers or copolymers. As an organic solvent, for example, hydrocarbons, ethers, esters, ketones, alcohols and the like are dispersed so that a dielectric paste having an appropriate viscosity can be obtained by dispersing barium titanate powder, glass powder, and a resin binder. An organic solvent is mentioned. Further, a dispersant may be added in order to make the dispersion better.

  The capacitor-embedded glass ceramic multilayer wiring board includes a dielectric layer 1 made of barium titanate formed inside an insulating substrate 3 made of glass ceramics, and Ag, Cu, Ag-Pt, A capacitor-embedded glass-ceramic multilayer wiring board comprising an electrode layer 2 made of either Ag—Pd or Cu—W, wherein the dielectric layer 1 is made of barium titanate 85.0 to 99.5. It consists of 0.5 to 15.0 parts by mass of glass containing alkali metal, and the crystal grain size of barium titanate is 0.3 μm to 0 at a 50% particle size distribution in the number cumulative particle size distribution. .8 μm.

  Since the electrode layer 2 is composed of any one of Ag, Cu, Ag—Pt, Ag—Pd, and Cu—W, the electrode layer 2 has a small electric resistance value, so that it enters the semiconductor element mounted on the substrate. The transmission speed of the output high frequency signal does not slow down. In addition, since the barium titanate crystal of the dielectric layer 1 is 0.3 μm to 0.8 μm with a 50% particle size in the number cumulative particle size distribution, the dielectric constant is high, and the temperature change rate of the dielectric constant is Since it has a small tetragonal structure, it becomes a glass-ceramic multilayer wiring board with a built-in capacitor having a large capacitance and a capacitor with a small temperature change rate of the capacitance.

  The crystal grain size of barium titanate in the dielectric layer 1 is calculated from the crystal grain size of barium titanate that appears on the cross section of the dielectric layer 1 after cutting the glass ceramic multilayer wiring board with a built-in capacitor. As a specific method, the substrate is first cut and the cross section is polished to make the dielectric layer 1 formed therein observable from the outside, and then a scanning electron microscope, a transmission electron microscope, etc. Cross-sectional observation is performed using. Next, the crystal grain size of barium titanate is measured from the obtained cross-sectional image, and the 50% particle size in the number cumulative particle size distribution is calculated. The cross-section is preferably observed at a magnification of 5000 times or more.

  The glass ceramic substrate with a built-in capacitor is manufactured as follows. First, a green sheet that is a precursor of the insulating substrate 3 is formed. The green sheet is obtained by adding and mixing a glass or a mixture of glass and ceramic powder and a resin binder with a solvent (organic solvent, water, etc.) and, if necessary, a predetermined amount of plasticizer and dispersant. This is obtained by molding on a support such as a PET film by a doctor blade method, a lip coater method, a die coater method or the like.

Examples of the ceramic powder include Al ₂ O ₃ , SiO ₂ , composite oxide of ZrO ₂ and alkaline earth metal oxide, composite oxide of TiO ₂ and alkaline earth metal oxide, Al ₂ O ₃ and SiO _{2. And} composite oxides containing at least one selected from ₂ (for example, spinel, mullite, cordierite) and the like.

Examples of the glass include SiO ₂ —B ₂ O ₃ system, SiO ₂ —B ₂ O ₃ —Al ₂ O ₃ system, SiO ₂ —B ₂ O ₃ —Al ₂ O ₃ —MO system (where M is Ca, Sr, Mg, Ba or Zn), SiO ₂ —Al ₂ O ₃ —M ¹ O—M ² O system (provided that M ¹ and M ² are the same or different and Ca, Sr, Mg, Ba or Zn are SiO ₂ —B ₂ O ₃ —Al ₂ O ₃ —M ¹ O—M ² O system (where M ¹ and M ² are the same as above), SiO ₂ —B ₂ O ₃ —M ³ ₂ O system (provided that M ³ represents Li, Na or K), SiO ₂ —B ₂ O ₃ —Al ₂ O ₃ —M ³ ₂ O system (provided that M ³ is the same as above), SiO 2 _2- Bi ₂ O ₃ system, SiO ₂ —B ₂ O ₃ —Bi ₂ O ₃ system, SiO ₂ —B _{2 O 3 -Al 2 O 3 -Bi 2} O 3 system, and the like.

  As the resin binder, those conventionally used for ceramic green sheets can be used. For example, acrylic resins (acrylic acid, methacrylic acid or their homopolymers or copolymers, specifically acrylic Acid ester copolymer, methacrylate ester copolymer, acrylic ester-methacrylic ester copolymer, etc.), polyvinyl butyral, polyvinyl alcohol, acrylic-styrene, polypropylene carbonate, cellulose and other homopolymers Or a copolymer is mentioned.

  As the solvent, for example, water or hydrocarbons, ethers, esters, ketones, alcohols are used so that a slurry having a viscosity suitable for green sheet molding can be obtained by dispersing glass powder, ceramic powder, and resin binder. And organic solvents such as

  Next, the electrode layer 2 is formed on the obtained green sheet. As a method of forming the electrode layer 2 on the green sheet, for example, a conductive paste obtained by pasting a conductive material powder is printed by a screen printing method or a gravure printing method, or a metal having a predetermined pattern shape by a plating method or a vapor deposition method. A method of directly forming on a green sheet to form a film, or a conductor thick film formed into a predetermined pattern shape by printing, a metal foil processed into a predetermined pattern shape, a predetermined pattern shape formed by a plating method or a vapor deposition method, etc. There is a method of transferring a metal film onto a green sheet. Examples of the conductive material include one kind or two or more kinds such as Au, Ag, Cu, Pd, and Pt. In the case of two or more kinds, any form such as mixing, alloy, and coating may be used. The electrode layer 2 includes a wiring layer other than the electrode layer 2 for forming a capacitor.

  The conductor material powder used for the conductor paste has a diameter of 5 μm or less in order to prevent the respective components of the insulating substrate 3 and the dielectric layer 1 from interdiffusion during firing and the dielectric constant of the dielectric layer 1 to decrease. It is preferable that the particle diameter is fine.

  The resin binder and the organic solvent used for the conductive paste are not particularly limited as long as they can be fired simultaneously with the green sheet to be the insulating substrate 3, and for example, the resin binder and the organic solvent blended in the green sheet Similar ones can be used.

  Before forming the electrode layer 2, if necessary, the electrode layer 2 is connected to other conductor layers above and below the insulating layer, or a through-hole conductor or a through-hole conductor is connected to connect the conductor layers. A conductor may be formed. These through conductors are formed by means such as embedding a conductive paste obtained by pasting a conductive material powder into a through hole formed in a lean sheet by punching, laser processing, or the like by printing or press filling.

  Next, the dielectric layer 1 is formed using the dielectric paste described above. The forming method is a method in which a dielectric paste is printed on the electrode layer 2 formed on the green sheet by a screen printing method or a gravure printing method, or a method using a dielectric paste as a slurry. A method of producing a dielectric green sheet by a molding method such as a blade method, a lip coater method, or a die coater method and laminating the dielectric green sheet on the green sheet on which the electrode layer 2 is formed can be used. In the case of forming by printing a dielectric paste, in the case of a method in which a conductive paste is further printed on the formed dielectric layer 1 to form the upper electrode layer 2 and a dielectric green sheet is laminated, On the upper surface of the body green sheet, the upper electrode layer 2 formed is laminated. In either case, the dielectric layer 1 may be a single layer or may be a plurality of layers formed so that the dielectric layers 1 and the electrode layers 2 are alternately overlapped in order to obtain a capacitor having a higher capacity.

  Next, a plurality of green sheets including the green sheet on which the dielectric layer 1 is formed are aligned and stacked, and a green sheet stacked body is manufactured by pressure bonding. The pressure bonding is performed by applying a pressure of about 3.0 to 8.0 MPa, and heating is performed at 35 to 80 ° C. as necessary. In order to obtain sufficient adhesion between the green sheets, an adhesive prepared by mixing an organic solvent and a resin binder with the green sheets may be used.

  Finally, the green sheet laminate is fired to produce the capacitor-embedded glass ceramic multilayer wiring board of the present invention. The firing step consists of removing organic components and sintering the ceramic powder. The organic component is removed by heating the green sheet laminate in a temperature range of 100 to 800 ° C., the organic component is decomposed and volatilized, and the sintering temperature varies depending on the ceramic composition, and is within a range of about 800 to 1000 ° C. Do. The firing atmosphere varies depending on the ceramic powder and the conductor material, and is performed in the air, in a reducing atmosphere, in a non-oxidizing atmosphere or the like, and may contain water vapor or the like in order to effectively remove organic components.

In order for the dielectric layer 1 to have a barium titanate crystal grain size of 0.3 μm to 0.8 μm with a 50% grain size distribution in the number cumulative particle size distribution, the glass containing the alkali metal of the dielectric layer 1 is in a liquid phase. In such a temperature range, the grains may be held so as to grow until the crystal grain size becomes 0.3 μm to 0.8 μm. For example, when SiO ₂ —B ₂ O ₃ —Li ₂ O-based glass that becomes a liquid phase at 750 ° C. or higher is used, it may be fired at 900 ° C. for about 60 minutes.

If a constrained green sheet is further laminated on the upper and lower surfaces of the green sheet laminate and fired, and the constrained sheet is removed after firing, a glass ceramic multilayer substrate with a higher dimensional accuracy can be obtained. The constrained green sheet is a green sheet mainly composed of a hardly sinterable inorganic material such as Al ₂ O ₃ and does not shrink during firing. In the laminate in which the constraining green sheets are laminated, the constraining green sheet that does not shrink is prevented from shrinking in the laminating plane direction (xy plane direction), and shrinks only in the laminating direction (z direction). Is suppressed.

  In addition to the hard-sintering inorganic component, the constrained green sheet may contain a glass component having a softening point not higher than the firing temperature, for example, the same glass as the glass in the green sheet. This is because when the glass is softened and bonded to the green sheet during firing, the bond between the green sheet and the constraining green sheet becomes strong, and a more reliable restraining force can be obtained. When the glass amount at this time is 0.5 to 15% by mass with respect to the inorganic component including the hardly sinterable inorganic component and the glass component, the binding force is improved and the firing shrinkage of the constraint green sheet is 0.5%. It is suppressed to the following.

  After firing, the constraining sheet attached to the both surfaces of the substrate without peeling is removed. Examples of the removal method include polishing, water jet, chemical blasting, sand blasting, wet blasting (a method of spraying abrasive grains and water by air pressure) and the like.

  Examples of the dielectric paste and capacitor-embedded glass ceramic multilayer wiring board of the present invention will be described below.

In order to obtain a glass ceramic green sheet serving as an insulator layer, 60 parts by mass of SiO ₂ —CaO—MgO glass powder as glass and 40 parts by mass of Al ₂ O ₃ powder as ceramic powder are mixed, and this inorganic powder 100 12 parts by mass of an acrylic resin as a resin binder, 6 parts by mass of a phthalic acid plasticizer, and 30 parts by mass of toluene as a solvent were added to parts by mass, and mixed by a ball mill method to obtain a slurry. Using this slurry, a glass ceramic green sheet having a thickness of 200 μm was formed by a doctor blade method.

  Next, two sheets of a first glass ceramic green sheet and a second glass ceramic green sheet were prepared from this glass ceramic green sheet.

  First, through holes serving as via holes were formed in the first glass ceramic green sheet and the second glass ceramic green sheet by mechanical processing. This through hole was processed so that the cross-sectional shape was a circle having a diameter of 0.2 mm.

  Next, a conductor paste made of Cu, a glass composition, a resin binder, and an organic solvent was filled into the through holes formed in the first glass ceramic green sheet and the second glass ceramic green sheet.

  Next, a conductor paste was applied on the second glass ceramic green sheet by a screen printing method to form an electrode pattern having a length of 1.3 mm × width of 1.3 mm × thickness of 12 μm.

As a powder contained in the conductor paste, a mixture of 98.0 parts by mass of Cu powder and 2.0 parts by mass of SiO ₂ —B ₂ O ₃ glass powder was used. To 100 parts by mass of this powder, 10.9 parts by mass of an acrylic resin as a resin binder and 1.5 parts by mass of terpineol as an organic solvent were added and kneaded to form a paste.

  Next, the organic solvent in the printed conductor paste was dried with hot air at 80 ° C.

Next, a dielectric paste is applied on the conductive paste formed on the surface of the second glass ceramic green sheet by a screen printing method to form a dielectric pattern having a length of 1.7 mm × width of 1.7 mm × thickness of 27 μm. did. As the powder in the dielectric paste, 95.0 parts by mass of barium titanate powder having a 50% particle size distribution of 0.10 μm in the number cumulative particle size distribution, and SiO ₂ —B ₂ containing Li as an alkali metal as glass. O ₃ was used a mixture of a -Li ₂ O-based glass 5.0 parts by weight. To 100 parts by mass of this powder, 30.0 parts by mass of an acrylic resin as a resin binder, 3.0 parts by mass of a nonionic dispersant, and 3.0 parts by mass of terpineol as an organic solvent were added and kneaded to obtain a paste.

  Next, the organic solvent in the printed dielectric paste was dried with 80 ° C. hot air.

  Next, a conductor paste was applied on the dielectric paste formed on the surface of the second glass ceramic green sheet to form an electrode pattern having a length of 1.3 mm × width of 1.3 mm × thickness of 12 μm.

  Next, the organic solvent in the printed conductor paste was dried with hot air at 80 ° C.

  Next, in order to form an electrode pad necessary for applying the probe, a conductor paste was applied to the surface of the first glass ceramic green sheet and the back surface of the second glass ceramic green sheet to form a wiring conductor pattern.

  Next, the organic solvent in the printed conductor paste was dried with hot air at 80 ° C.

  Next, the first glass ceramic green sheet and the second glass ceramic green sheet were superposed and vacuum pressed at a pressure of 5.6 Pa and a temperature of 55 ° C. to obtain a glass ceramic green sheet laminate.

Next, the glass ceramic green sheet laminate on which the capacitor to be built was formed was baked at 915 ° C. for 40 minutes in an N ₂ atmosphere to produce the capacitor built-in glass ceramic multilayer wiring board of Example 1. As an atmosphere in the firing process, N ₂ passed through warm water of 50 ° C. was supplied into the furnace in order to decompose the resin binder and the organic solvent contained in the dielectric layer 1, the electrode layer 2, and the glass ceramic green sheet. It was.

Further, as Comparative Example 1, a glass ceramic multilayer wiring board with a built-in capacitor was produced in the same manner as in Example 1 except that SiO ₂ —B ₂ O ₃ -based glass containing no alkali metal was used for the dielectric paste. did.

The electric capacity of the capacitors of the glass-ceramic multilayer wiring board with built-in capacitors of Example 1 and Comparative Example 1 thus obtained was measured. The capacitance was measured using an impedance measuring instrument (model “4294A Precision Impedance Analyzer”, measurement accuracy ± 0.08%, manufactured by Agilent Technologies) under the conditions of a measurement frequency of 1 MHz and a measurement temperature of 25 ° C. The results of measuring the capacitance value are shown in Table 1.

  From Table 1, it can be seen that the capacitor of Example 1 in which an alkali metal is added to the glass in the dielectric paste has a higher capacitance value than the capacitor of Comparative Example 1 manufactured without adding an alkali metal. From this, the dielectric layer 1 with a high dielectric constant was able to be obtained with the calcination temperature of 1000 degrees C or less by making the glass in a dielectric paste contain an alkali metal.

Further, as Example 2, a glass-ceramic multilayer wiring board with a built-in capacitor was produced by the same method as in Example 1. Further, as Comparative Example 2, a capacitor-embedded glass-ceramic multilayer wiring board was produced in the same manner as in Example 2 except that SiO ₂ —PbO-based glass containing Pb in the dielectric paste was used.

  The temperature change rate of the electric capacity of the capacitors of the glass-ceramic multilayer wiring board with built-in capacitors of Example 2 and Comparative Example 2 thus obtained was measured. The measurement was performed in a temperature range of −55 ° C. to 125 ° C. The maximum value and the minimum value of the capacity value in this temperature range were calculated, and each capacity value was calculated as the rate of change from the value at room temperature. The capacitance was measured using an impedance measuring instrument (model “4294A Precision Impedance Analyzer”, measurement accuracy ± 0.08%, manufactured by Agilent Technologies) under the conditions of a measurement frequency of 1 MHz and a measurement temperature of 25 ° C.

  Further, the crystal grain size of the dielectric layer 1 of the capacitor was measured. That is, first, the cross section of the glass ceramic multilayer wiring board with a built-in capacitor was mirror-polished and then observed with an electron microscope (magnification 10,000 times, model “scanning electron microscope JSM-6340F”, manufactured by JEOL Ltd.). Next, the crystal grain size of barium titanate was measured from the obtained image, and the 50% particle size in the number cumulative particle size distribution was calculated.

Table 2 shows the results obtained by measuring the maximum change rate, the minimum change rate, and the 50% particle size distribution in the number cumulative particle size distribution of barium titanate in the dielectric layer. In addition, as one of the guidelines for the rate of change in the temperature of the capacitance, the standard was within ± 15%, which is one of the standards for the rate of change in temperature of the multilayer ceramic capacitor.

  From Table 2, in the capacitor of Example 2 in which the glass in the dielectric paste contains an alkali metal, the 50% particle size distribution in the number cumulative particle size distribution of the dielectric layer 1 is in the range of 0.3 μm to 0.8 μm. The rate of change in the temperature of the capacitance was within the standard ± 15%.

  On the other hand, in the capacitor of Comparative Example 2, the 50% particle size distribution in the number cumulative particle size distribution of the dielectric layer 1 exceeded 0.8 μm, and the temperature change rate of the capacitance was also outside the standard ± 15% range. .

  Thereby, the glass in the dielectric paste contains an alkali metal, and the 50% particle size in the particle number cumulative particle size distribution of the barium titanate of the dielectric layer 1 is set to 0.3 μm to 0.8 μm, It has become possible to obtain a capacitor in which barium titanate is sintered at a low temperature of 1000 ° C. or less and the temperature change rate of the capacitance is within the specification of the temperature change rate of the multilayer ceramic capacitor.

Next, as Examples 3 to 5, using a SiO ₂ —B ₂ O ₃ —CaO—MgO—Li ₂ O-based glass in which Li, Ca, and Mg, which are alkali metals, are contained in a dielectric paste, firing is performed. A glass-ceramic multilayer wiring board with a built-in capacitor was produced in the same manner as in Example 1 except that the temperature was changed.

Further, as Comparative Examples 3 to 5, a glass-ceramic multilayer wiring board with a built-in capacitor was produced by the same method as in Example 1 except for the firing temperature. Table 3 shows firing temperatures of Examples 3 to 5 and Comparative Examples 3 to 5.

  With respect to the obtained glass ceramic multilayer wiring board with a built-in capacitor, the temperature change rate of the electric capacity of the capacitor and the crystal grain size of the dielectric layer 1 of the capacitor were measured in the same manner as in Example 2. Table 3 shows the maximum rate of change and the minimum rate of change of the obtained capacitance value from room temperature, and the 50% particle size in the number cumulative particle size distribution of barium titanate in the dielectric layer 1.

  As a guideline for the rate of change in the temperature of the capacitance, the standard was within ± 15%, which is one of the standards for the rate of change in temperature of the multilayer ceramic capacitor.

  From Table 3, the capacitors of Examples 3 to 5 in which Li, Ca, and Mg, which are alkali metals, are contained in the glass in the dielectric paste, the number of dielectric layers 1 regardless of the firing temperature. The 50% particle size in the cumulative particle size distribution was in the range of 0.3 μm to 0.8 μm, and the temperature change rate of the dielectric layer 1 from room temperature was within ± 15%.

  On the other hand, the capacitors of Comparative Examples 3 to 5 in which the alkali metal is not contained in the glass in the dielectric paste have a 50% particle size of 0 in the number cumulative particle size distribution compared to those manufactured at a firing temperature of 935 ° C. .8 μm is exceeded and the temperature change rate is not within ± 15%. Thus, the capacitors of Examples 3 to 5 in which Li, Ca, and Mg, which are alkali metals, were included in the glass in the dielectric paste, and Comparative Example 3 in which the glass in the dielectric paste contained the alkali metal. It was possible to obtain a desired capacitor in a wider firing temperature range than the capacitors of ~ 5. As a result, it became possible to sinter barium titanate at a low temperature of 1000 ° C. or lower and supply a capacitor with a small temperature change rate more stably.

It is sectional drawing which shows an example of embodiment of the glass ceramic multilayer wiring board with a built-in capacitor | condenser of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Dielectric layer 2 ... Electrode layer 3 ... Insulating substrate

Claims (4)

85.0 to 99.5 parts by mass of barium titanate powder, 0.5 to 15.0 parts by mass of glass powder containing an alkali metal, and a resin binder and an organic solvent. Dielectric paste. The particle size of the barium titanate powder is less than 0.8 μm at 50% particle size distribution in the number cumulative particle size distribution, and the glass powder is composed of Ca, Mg, Mn, Zn, Nb, Co, Bi and Sn. 2. The dielectric paste according to claim 1, comprising at least one of them. A dielectric layer made of barium titanate formed inside an insulating substrate made of glass ceramic, and Ag, Cu, Ag-Pt, Ag-Pd, and Cu- formed on the upper and lower main surfaces of the dielectric layer, respectively. A capacitor built-in glass ceramic multilayer wiring board comprising an electrode layer made of any of W, wherein the dielectric layer contains 85.0 to 99.5 parts by mass of barium titanate and an alkali metal And the crystal grain size of the barium titanate is 0.3 μm to 0.8 μm with a 50% particle size in the number cumulative particle size distribution. Capacitor built-in glass ceramic multilayer wiring board. 4. The glass-ceramic multilayer wiring board with a built-in capacitor according to claim 3, wherein the dielectric layer contains at least one of Ca, Mg, Mn, Zn, Nb, Co, Bi, and Sn.

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