JP4748701B2 - Low-temperature fired porcelain composition and wiring board using the same - Google Patents

Description

[0001]
[Technical field to which the present invention pertains]
The present invention relates to a low-temperature fired ceramic composition and a wiring board using the same, and more particularly to a low-temperature fired ceramic composition suitable for high frequency use and a wiring board using the same.
[0002]
[Prior art]
Conventionally, for example, as a wiring board on which electronic parts such as LSI, IC, or discrete parts are mounted, or a wiring board in which various thick film printing elements are built in the wiring board, a relatively high density wiring is used. Possible multilayer wiring boards are frequently used. In this specification, the multilayer board is collectively referred to as a wiring board.
In recent years, high frequency bands from the microwave band to the millimeter wave band have been actively adopted for wireless communication such as cellular phones in order to measure the expansion of radio wave resources and the increase in transmission capacity. Demand for wiring boards for handling high-frequency signals as parts for wireless communication devices used for this is increasing explosively.
[0003]
When handling the above-mentioned high-frequency signal, the wiring connecting the operation power supply of the electronic component and the electronic component contributes as inductance, so that malfunctions caused by noise superimposed on the wiring etc., delay in the operation response of the electronic component, or In some cases, problems such as transmission loss of high-frequency signals may occur. In order to suppress such problems peculiar to high-frequency signals that were not a problem with low-frequency signals, the wiring layer is made of a low-resistivity material such as Ag or Cu, while the dielectric layer is made low. It is necessary to use a wiring board made of a material having a dielectric constant and a low dielectric loss even in a high frequency band.
[0004]
However, when Ag or Cu having a melting point as low as about 1000 ° C. is adopted as the material of the wiring layer, in order to form the wiring substrate by simultaneously firing the wiring layer and the insulating layer, the insulating layer has its firing temperature. Needs to be made of a material that can be fired at a low temperature of 800 to 1050 ° C. As a material that can be fired at a low temperature, has a low dielectric constant, and has a low dielectric loss even in a high frequency band, various types of crystallized glass mainly composed of borosilicate glass and crystals precipitated at the firing stage have been proposed. For example, as a glass ceramic material composed of glass and an inorganic filler, B in glass₂O₃Examples in which sinterability is ensured by increasing the amount are disclosed (Patent Documents 1 to 3).
[0005]
[Patent Document 1]
JP-A-3-141153
[Patent Document 2]
Japanese Patent Laid-Open No. 9-142876
[Patent Document 3]
JP-A-7-45958
[0006]
[Problems to be solved by the invention]
But B₂O₃A glass-ceramic material using a large amount of glass has a problem in that boric acid crystals may be deposited on the ceramic green sheet, which deteriorates handling properties. This is B in the glass₂O₃Is chemically unstable and reacts with moisture in the air. As a method for suppressing boric acid crystals, JP-A-7-45958 describes a method of adding a base into a ceramic green sheet. However, this method has a problem that the binder removal property and the characteristics of the sintered body vary depending on the type and amount of the additive.
Moreover, in the glass composition, when the melting temperature of the glass component is set to about 1450 ° C. and low-temperature firing is performed at about 800 to 1050 ° C., it is necessary to add a metal component such as alkali metal, Pb, As, and Sb. It was. However, these metal component oxides increase the dielectric loss in the high frequency band of the wiring board made of the sintered body and the low-temperature fired ceramic composition.
[0007]
The present invention has been made in consideration of such problems. That is, the present invention is a low-temperature fired ceramic composition that is suitable for electrical characteristics in high-frequency signals, has no precipitation of boric acid crystals when formed into a ceramic green sheet, and has a wide range of optimum firing conditions, and wiring using the same An object is to provide a substrate.
[0008]
[Means for solving the problems and actions / effects]
  In order to solve the above problems, the low-temperature fired porcelain composition of the present invention comprises SiO 2₂, B₂O₃, Al₂O₃, Containing metal oxide RO, SiO₂, B₂O₃, Al₂O₃When the total amount of RO is 100 mol%, SiO₂Content of 68-72 mol%, B₂O₃The content of 14 ~22mol%, Al₂O₃Content is 4 to 11 mol%, RO content is 4 to 11 mol%, and SiO₂And B₂O₃And the total amount is 92 mol% or less, and B₂O₃B represented by / RO₂O₃And the molar ratio of RO is 1.3 to 4, and the metal oxide RORIs composed of at least one component selected from Ca, Sr, Mg, and Zn, and when the total amount of the metal oxide RO is 100 mol%, CaO has a content of 60 mol% or more, an alkali metal, Glass containing no Pb, As and Sb, and SiO₂Or Al₂O₃And at least one of the inorganic fillersThe glass content is 55 to 80% by volume, and the inorganic filler content is 20 to 45% by volume.It is characterized by that.
[0009]
The glass of the present invention is made of SiO.₂And B₂O₃Is a borosilicate glass containing as a main component and does not contain an alkali metal content, and therefore has a low dielectric loss despite being amorphous. Moreover, by setting it as the composition which a crystal | crystallization does not precipitate in a baking process (1050 degrees C or less), the width | variety of the optimal baking conditions is wide and it becomes what was excellent in mass-productivity.
[0010]
  The glass is made of SiO₂, B₂O₃, Al₂O₃, RO (R is at least one selected from Ca, Sr, Mg, Zn). SiO in the glass₂And B₂O₃The total amount is preferably 84 to 92 mol%. This is because the dielectric constant and dielectric loss increase when the content is 84 mol% or less. When it is 92 mol% or more, SiO₂This is because system crystals (for example, cristobalite) are precipitated. SiO in the glass₂amountIsThis is because the dielectric constant increases if it is less than 55 mol%. This is because if it exceeds 72 mol%, sintering cannot be performed.. TheB in glass₂O₃The amount is 14 to 26 mol%, particularly 16 to 24 mol%, more preferably 18 to 22 mol%. This is because if it is less than 14 mol%, sintering cannot be performed. It is because degreasing property will fall when it is larger than 26 mol%. Al in the glass₂O₃The amount is desirably 4 to 11 mol%. If it is less than 4 mol%, vitrification may be separated or SiO₂This is because system crystals are precipitated. Al is greater than 11 mol%₂O₃This is because crystals and feldspar precipitate. As for the RO amount of this glass, 4-11 mol% is desirable. This is because it is difficult to melt the glass if it is less than 4 mol%. This is because if it exceeds 11 mol%, the dielectric constant and dielectric loss increase. If the RO amount is 8 mol% or less, more preferably 6 mol% or less, the dielectric loss can be remarkably reduced, which is desirable.
[0011]
B of this glass₂O₃The relationship between quantity and RO quantity is B₂O₃B represented by / RO₂O₃And the molar ratio of RO is 1.3-4. This is because if it is less than 1.3, the dielectric loss increases, and it is particularly desirable that it be 2 or more, and more preferably 3 or more. If it is larger than 4, boric acid crystals will be deposited on the ceramic green sheet.
[0012]
The low-temperature fired porcelain composition of the present invention contains B in glass.₂O₃The fact that boric acid crystals do not precipitate on the ceramic green sheet despite the large amount is due to the following action. The boric acid crystals are deposited on the green sheet because the water in the air reacts with the glass during storage of the green sheet, and the B component elutes once in the moisture.₃BO₃It is thought that it is recrystallized as a plate-like crystal. On the other hand, boric acid forms salts with alkali (earth) oxides, and the formed salts RO and B₂O₃The ratio of RO to 1 mol of RO is B₂O₃Is known to exist up to 4 mol of octaborate. From this, B in the glass₂O₃Amount B₂O₃If the RO ratio is 4 or less, B₂O₃Even if it elutes in water, it is considered that boric acid crystals do not precipitate because a salt with R ions that would be easily eluted with respect to water is formed without deficiency.
[0013]
R of RO is at least one selected from Ca, Sr, Mg and Zn, but in order to obtain stable sinterability and high yield during mass production, Ca is an essential component and the total amount of RO When the content of CaO is 100 mol%, the content of CaO is preferably 60 to 100 mol%, and Sr, Mg, and Zn are preferably optional components. This is because CaO has a wide vitrification range and phase separation and crystallization are unlikely to occur. If CaO is less than 60 mol%, crystallization may occur or viscosity may increase and sinterability may decrease.
[0014]
Conventionally, in the above-mentioned crystallized glass or a glass composition that remains amorphous without crystal precipitation, when the melting temperature of the glass component is about 1450 ° C. and low-temperature firing is performed at about 800 to 1050 ° C., It was necessary to add metal components such as alkali metal, Pb, As and Sb. However, these metal component oxides increase the dielectric loss in the high frequency band of the wiring board made of the sintered body and the low-temperature fired ceramic composition.
[0015]
The low-temperature fired ceramic composition of the present invention can be fired at a low temperature of 1050 ° C. or less without containing metal components such as alkali metals, Pb, As and Sb, and is amorphous even after the low-temperature firing. It is possible to leave. As a result, it is possible to suppress problems such as increase in dielectric loss in the high frequency band due to the metal component oxide, and further to further reduce the dielectric loss in the high frequency band of the wiring board made of the low-temperature fired ceramic composition of the present invention. It becomes possible.
[0016]
In addition, the low-temperature fired ceramic composition of the present invention has an effect of enabling a reduction in relative dielectric constant and a reduction in dielectric loss corresponding to a high-frequency signal. Further, since it does not contain other components such as alkali metal, Pb, As, and Sb, it is possible to reduce the heterogeneous grain boundary formed in the firing process, and the amorphous nature such as crystal precipitation is impaired. Can be suppressed. As a result, the glass matrix contained in the low-temperature fired porcelain composition does not crystallize, and it is possible to suppress the problems that occur when the above-mentioned alkali metals are added, thus reducing the dielectric loss in the high-frequency band. can do.
[0017]
The glass preferably has a yield point of 700 to 900 ° C. Firing is usually performed in a state in which a binder made of an organic material is contained together with the constituent components constituting the low-temperature fired ceramic composition. The binder made of the organic material is removed by degreasing in the firing stage. If the yield point of the low-temperature fired ceramic composition is less than 700 ° C., the binder is densified before the removal of the binder by degreasing is completed. Therefore, the problem that the carbon component remains is likely to occur. On the other hand, if the yield point is 880 ° C. or higher, when the wiring layer of the wiring board is made of Cu or Ag having a low resistivity, the timing of firing shrinkage between the wiring layer and the insulating layer will not match. It becomes difficult to fire the wiring layer simultaneously. Especially preferably, it is 750-880 degreeC, More preferably, it is 800-880 degreeC.
[0018]
The inorganic filler of the present invention is SiO₂Or Al₂O₃The inorganic filler is preferably alumina, mullite, quartz, silica glass, and a mixture thereof, and particularly preferably alumina. This is because alumina is easy to obtain high-purity raw materials, so that dielectric loss can be easily reduced and the strength of the sintered body is improved. The inorganic filler preferably contains no alkali metal or alkaline earth metal. This is because when an alkali metal or alkaline earth metal is contained, the dielectric loss of the low-temperature fired ceramic composition as a fired body increases.
[0019]
  The glass is made of the SiO₂Content of 68-72 mol%TheSiO₂This is because, when the content is increased, the plating resistance is improved, and defects in the plating process are reduced.
[0020]
  The glass is RO / Al₂O₃Al represented by₂O₃It is desirable that the molar ratio of RO to RO is greater than 1 and 2 or less. The above glass powder has a small amount of RO to reduce dielectric loss, and B to suppress precipitation of boric acid crystals.₂O₃The upper limit of the amount is limited by the RO amount. For this reason, there exists a tendency for the viscosity of glass to rise and for sinterability to fall. RO / Al₂O₃By making the molar ratio of 1 greater than 1, good sinterability can be ensured even with a composition that contains a small amount of RO and does not contain harmful components such as Sb and Pb. RO / Al₂O₃Quantity is more than 2largeIn addition, it is not desirable because warping or phase separation occurs in the electrode portion when co-firing with the electrode.
[0021]
RO / Al₂O₃When the ratio is 1 or less, RO is not given non-bridging oxygen that cuts the tetrahedral structure of the glass-forming oxide, and the glass viscosity at the firing temperature is too high to sinter..
[0022]
The RO preferably includes MgO as an essential component. This is because MgO decreases the dielectric constant and dielectric loss. When the total amount of RO is 100 mol%, the amount of MgO is preferably 40 mol% or less, particularly preferably 20 mol% or less. This is because if it exceeds 40 mol%, crystallization is facilitated.
[0023]
  In the low-temperature fired ceramic composition containing the glass and the inorganic filler, the glass content is 55 to 80% by volume, and the inorganic filler content is 20 to 45% by volume.TheThis is because if the glass content is less than 55% by volume, a dense sintered body cannot be obtained. This is because if it is 80% by volume or more, the binder removal property is lowered, and the dimensional variation of the fired body is increased. Particularly preferably, the glass content is 55 to 70% by volume, and the inorganic filler content is 30 to 45% by volume. More preferably, the glass content is 55 to 65% by volume, and the inorganic filler content is 35 to 45% by volume.
[0024]
After the low-temperature fired ceramic composition is fired at 850 to 1050 ° C., the crystal phase contained is only the crystal phase contained in the inorganic filler. Since there are no crystals resulting from crystallization of the glass powder, the crystal phase in the sintered body is only the crystal phase contained in the inorganic filler. If there are crystals resulting from the crystallization of the glass powder, the crystallinity changes depending on the firing conditions, so that the high-frequency characteristics greatly depend on the firing conditions. For this reason, the optimum firing conditions are narrow, and it is difficult to put out the conditions. Glass that crystallizes once in the firing process and then loses fluidity as it crystallizes. For this reason, it is difficult to correct the warping of the substrate that occurs during the firing process under the firing conditions. Since the low-temperature fired ceramic composition of the present invention is made of glass that does not crystallize, the above problems hardly occur and the range of optimum firing conditions can be widened.
[0025]
It should be noted that the glass of the present invention in this specification is amorphous, and that the sintered body does not precipitate crystals caused by the glass, even after heat treatment such as baking or annealing at 1050 ° C. or lower. Component of glass (when crystalline filler particles are added as inorganic filler, this inorganic filler is excluded. For example, SiO₂, Al₂O₃, Inorganic fillers such as mullite and enstatite. ) Is not formed in the glass matrix (portion made of glass). Further, the fact that the crystal phase is not formed means that when a sintered body obtained by a heat treatment at 1050 ° C. or less is measured by X-ray diffraction for a molded body using a low-temperature fired ceramic composition, When crystalline filler particles are added as an inorganic filler, this inorganic filler is excluded, for example, SiO.₂, Al₂O₃, Inorganic fillers such as mullite and enstatite. The diffraction pattern observed in the presence of a crystal phase due to ()) does not appear.
[0026]
According to the low-temperature fired ceramic composition, it is possible to obtain a ceramic having excellent high frequency characteristics such as a dielectric constant of 7 or less and a dielectric loss at 10 GHz of 0.003 or less. The relative dielectric constant is usually 3 or more, particularly 6.5 or less, more preferably 6 or less. The dielectric loss is particularly preferably 0.002 or less, and more preferably 0.0015 or less. As described above, the low dielectric constant and the dielectric loss in the high frequency band are reduced, and the low-temperature fired porcelain composition of the present invention causes problems such as transmission loss of the high-frequency signal, which is a problem when handling high-frequency signals. Can be suppressed. Here, the dielectric constant and dielectric loss may be measured by known methods. For example, it can be measured in the TE011 mode of the both-end short-circuited dielectric resonator method described in JIS R 1627.
[0027]
In a wiring board in which a wiring layer is formed on the surface and / or inside of the board, by using the low-temperature fired ceramic composition of the present invention for the insulating layer, a wiring board that is excellent in simultaneous sintering and suitable for high-frequency signals can do. Conventionally, when the above-described crystallized glass is used for a substrate and simultaneously fired with a wiring layer, the fluidization of the glass component is suppressed in the firing step, and thus the formed wiring substrate may be warped. However, since the glass matrix contained in the low-temperature fired porcelain composition of the present invention does not crystallize, it is possible to suppress warpage of the formed wiring board, and to improve electrical characteristics such as reduction in transmission loss of electrical signals. Make it possible. By the way, as a component of the low-temperature fired ceramic composition, in addition to glass, crystalline inorganic fillers (for example, alumina, quartz, garnite, diopside, spinel, enstatite, cordierite, anorsite, etc.) are used as additives. When used in combination, the glass matrix itself is amorphous with no crystallized crystal phase, but the entire sintered body contains a crystallized crystal phase. Such a case is included in the technical scope of the present invention as long as the glass matrix itself is not crystallized.
[0028]
Further, in a wiring board that supports high-frequency signals, the wiring layer is required to use a material such as Cu, Ag, or Au having a low resistivity. In that case, since Cu, Ag, and Au have a low melting point, in order to simultaneously fire the wiring layer and the substrate, the material used for the substrate can be formed by low-temperature firing at about 800 to 1050 ° C. There is a need. Since the firing temperature of the low-temperature fired ceramic composition of the present invention can be set to 1050 ° C. or lower, a substrate can be formed using the low-temperature fired ceramic composition, and a wiring board suitable for high-frequency signals and can do.
[0029]
In particular, among Cu, Ag, and Au, Cu and Ag are suitable for the material of the wiring layer because Cu and Ag have a low resistivity, and Cu that is more excellent in migration resistance than Ag is most suitable. However, Cu is oxidized when fired in an oxidizing atmosphere including the atmosphere, causing problems such as increased resistance of the wiring layer. Therefore, normally, when the substrate and the wiring layer using Cu are simultaneously fired, the reduction or neutral atmosphere is performed. At this time, as described above, the substrate is usually fired in a state in which a binder made of an organic material is contained together with the low-temperature fired ceramic composition which is a component of the substrate. The binder is removed by degreasing in the firing stage, but the higher the firing temperature, the higher the binder removal effect. However, when the firing temperature is increased, the temperature becomes too close to the melting point of Cu used for the wiring layer, and Cu is pre-sintered in the firing process, making simultaneous firing with the substrate difficult. In addition, since the binder removal conditions vary depending on the size and shape of the fired body, when firing the low-temperature fired ceramic composition and the wiring layer made of Cu simultaneously, the firing conditions such as the firing temperature are optimized. The wider the better.
[0030]
In the present invention, as described above, the low-temperature fired porcelain composition can be fired with a wider range of optimization of the firing conditions such as the firing temperature as compared with the conventional crystallized glass. Therefore, by simultaneously firing the low-temperature fired porcelain composition of the present invention and a wiring layer using Cu, it is possible to form a wiring board that has excellent simultaneous sintering properties and suppresses problems such as warping. It is.
[0031]
As a result, a wiring board suitable for high-frequency signals can be obtained, and productivity such as the yield of the wiring board can be improved.
[0032]
DETAILED DESCRIPTION OF THE INVENTION
Although it is a manufacturing method of the low-temperature baking ceramic composition of this invention, Although it does not specifically limit, the example is shown. After weighing and mixing the raw material element oxide in the raw material constituting the glass so that the composition after the firing becomes the above content, for example, after melting at about 1600 ° C. in a crucible, ball meal By pulverizing, etc., the glass powder used as the component of the low-temperature baking ceramic composition of this invention is obtained.
[0033]
The glass powder is preferably pulverized so that the average particle size is in the range of 1 to 3 μm. This is because when the average particle size is larger than 3 μm, the sinterability is lowered, and when the average particle size is less than 1 μm, the binder removal property is lowered.
[0034]
An inorganic filler, a binder made of an organic material, a solvent, and the like are added to the glass powder produced as described above and kneaded and formed into a sheet shape. Then, a sintered compact can be obtained by baking the shape | molded molded object on a porous ceramic setter.
[0035]
Examples of the binder include acrylic resins (for example, polymethyl methacrylate, poly t-butyl methacrylate), cellulose acetate butyrate, polyethylene, polyvinyl alcohol, and polyvinyl butyral. Solvents include acetone, methyl ethyl ketone, and diacetone. Methyl isobutyl ketone, benzene, bromochloromethane, ethanol, butanol, propanol, toluene, xylene and the like.
[0036]
Next, an embodiment in which the wiring board of the present invention is formed is shown in FIG.
FIG. 1 schematically shows a schematic cross-sectional view of a wiring board 1. A wiring layer 3 is formed inside a board 2, and a semiconductor element 51 is mounted on the surface of the wiring layer 3 as necessary. The Each wiring layer 3 is electrically connected to each other by a via hole 35 penetrating the wiring layer 3 in the thickness direction. The wiring board 1 may be provided with a high-frequency package or an active element function having high-frequency signal processing capability in order to function as, for example, a high-frequency multilayer ceramic wiring board, or may be configured separately. It may be an electronic component for mounting a high frequency element such as an antenna switch module.
[0037]
In the wiring board 1 of the present embodiment, the wiring layer 3 is configured with a ground conductor (not shown) functioning as a noise protection shield part. Furthermore, in the wiring board 1 of the present embodiment, various thick film circuit elements such as the capacitor 54, the inductor 53, and the resistor 55 are formed in addition to the wiring layer 3, but the thick film circuit element is particularly provided. It is also possible to configure as a substrate having only a wiring layer. Moreover, when the wiring board 1 is a multilayer ceramic wiring board for high frequency, a part of the wiring layer 3 can be configured as a strip line. The wiring board 1 in FIG. 1 is a multilayer wiring board, but the application of the present invention does not have the wiring layer 3, or a high-frequency metal wiring such as a high-frequency slot line or a coplanar waveguide. The present invention can be applied to a known wiring board. Furthermore, a connection terminal formed on the surface of the wiring board 1 when the electronic component 51 is mounted can be joined to a part of the wiring layer 3 of the present invention.
[0038]
The wiring board 1 shown in FIG. 1 can also be applied to a wiring board having a plurality of terminals for placing the surface opposite to the side on which the electronic component 51 is mounted on a mother board or the like. In other words, in the present invention, the connection reliability is improved by suppressing warpage during the formation of the substrate 2 which is the base of the wiring substrate 1, and the electronic component such as the capacitor 54 is formed inside, The present invention can be applied to a known wiring board in which connection terminals connected to the component 51 or the mother boat are formed on the front surface or the back surface.
[0039]
Next, an example of the manufacturing process will be described below by taking the wiring board as shown in FIG. 1 as a representative.
A green sheet to be the substrate 2 is prepared. The green sheet is composed of glass powder having an average particle diameter in the range of 1 to 3 μm, the inorganic filler, the same binder and solvent as described above, and a plasticizer (butylbenzyl phthalate, dibutyl). Phthalate, dimethyl phthalate, diethylhexyl phthalate, adipic acid ester, polyethylene glycol derivative, tricresol phosphate, etc.), peptizer (fatty acid (glycerin triolate, etc.), surfactant (benzenesulfonic acid, etc.), wetting agent ( Additives such as alkyl allyl polyether alcohol, polyethylene glycol ethyl ether, nithyl phenyl glycol, polyoxyethylene ester, etc.) are blended and kneaded, and formed into a sheet by a doctor blade method or the like.
[0040]
On the green sheet thus obtained, a plurality of wiring patterns to be a wiring layer (including a pattern of the element when a thick film circuit element is formed) are formed by a known screen printing method.
[0041]
When pattern formation is completed in this way, when producing a multilayer wiring board, another ceramic green sheet is overlaid thereon, and further, the pattern formation / green sheet lamination process is repeated, and thermocompression lamination is performed, whereby the laminate is obtained. obtain. In addition, when forming the via hole 35, it drills using a drill etc. in the via formation position of a green sheet, and fills it with a metal paste here.
[0042]
The metal material used for forming the wiring layer described above is silver-based (silver simple substance, silver-metal oxide (oxide of manganese, vanadium, bismuth, aluminum, silicon, copper, etc.), silver-glass addition, silver -Palladium, silver-platinum, silver-rhodium, etc.), gold-based (single gold, gold-metal oxide, gold-palladium, gold-platinum, gold-rhodium, etc.), copper-based (single copper, copper-metal oxide) , Copper-palladium, copper-platinum, copper-rhodium, etc.) or the like can be used.
[0043]
【Example】
Hereinafter, experimental results performed to confirm the effects of the present invention will be described.
[0044]
Example 1
In accordance with the manufacturing process described above, SiO₂, B₂O₃, Al₂O₃And an alkaline earth metal oxide CaO, MgO having an average particle size of 3 μm glass powder composed of a glass composition shown in Table 1 below, and alumina (Al₂O₃) Prepared with filler. These were prepared by mixing 64% by volume of glass powder and 36% by volume of alumina filler, and adding 4 parts by weight of an acrylic resin binder and a solvent to 100 parts by weight of the mixed powder. Then, after uniaxially forming the prepared granulated powder, CIP was performed at 150 MPa to obtain a molded body. Next, this compact was placed on a porous ceramic setter (ILS-ZRI manufactured by Isolite Kogyo Co., Ltd.) and fired at 950 ° C. for 2 hours in the air to obtain a sintered body. Content (mol%) of each component which comprises glass with respect to the sample number of the low-temperature baking ceramic composition in a present Example, B₂O₃B represented by / RO₂O₃And RO molar ratio, and RO / Al₂O₃Al represented by₂O₃Table 1 shows the molar ratio of NO to RO.
[0045]
[Table 1]
[0046]
The molded body was allowed to stand in an environment of 40 ° C. and 80% humidity for 7 days, and then the presence or absence of boric acid crystals was confirmed by observing whether crystals were precipitated on the surface.
Whether or not the glass matrix was amorphous was determined by X-ray diffraction measurement on the sintered body produced in the above example. Here, the case where a diffraction pattern accompanying crystallization is not observed is determined to be amorphous. Further, the water absorption was measured by the method of JIS C 2141.
In the evaluation of plating resistance, a fired sample having a thickness of 50 mm and a thickness of 1 mm was obtained. The fired sample was washed with 10 ml / l sulfuric acid, then pre-diped, subjected to Pd activation treatment, and immersed in an electroless Ni-P plating solution. After further washing with water, it was immersed in a substituted Au plating solution and further immersed in an electroless Au plating solution. Each of the sample before the plating treatment and the sample after the plating treatment was observed with an SEM, and the area of the glass component on the sample surface was calculated by image processing. The rate of reduction of the area after plating with respect to the area before plating is 0 to 10%, ◯ is 10 to 20%, and 20 to 40% is Δ.
The sintered body was processed into a size of 15 to 16 mm in diameter and 7.5 to 8 mm in thickness. Thereafter, the relative dielectric constant and dielectric loss of the low-temperature fired ceramic composition were measured by the method of JIS R 1627 under conditions of TE011 mode and a resonance frequency of 8 to 12 GHz. These measurement results are shown in Table 2.
[0047]
[Table 2]
[0048]
Sample numbers 1-15 are B₂O₃/ RO ratio is 4 or less. Low-temperature fired porcelain compositions made with these glass compositions are SiO₂Addition amount, Al₂O₃Regardless of the amount added, boric acid crystals did not precipitate on the surface of the pressed body. Sample numbers 16-18 are B₂O₃Although the / RO ratio was larger than 4, it was observed that crystals of boric acid were precipitated on the surface of the pressed body. Sample number 19 is B₂O₃Although the / RO ratio is smaller than 1, the low-temperature fired ceramic composition made with this glass composition has a too large dielectric loss and cannot be measured.
[0049]
Sample numbers 6, 7, 14, 16, 18 are RO / Al₂O₃The ratio is one. The low-temperature fired porcelain compositions prepared with these glass compositions had a water absorption rate exceeding 0.1%, and the densification was insufficient. Sample number 10 is RO / Al₂O₃Although the ratio was 2 or more, the glass after melting had some phase separation, and the glass was whitened.
[0050]
Sample Nos. 1 to 6 have RO of 6 mol% or less, but the low-temperature fired ceramic compositions prepared with these glass compositions were particularly good with a dielectric loss of 0.0015 or less. Sample No. 13 has a large RO of 14 mol%, but the low-temperature fired porcelain composition prepared with these glass compositions has a remarkably large dielectric loss.
[0051]
Sample numbers 2 to 6 are obtained by substituting part of CaO with MgO for RO. Low-temperature fired porcelain compositions made with these glass compositions have low dielectric constants and dielectric losses. However, in Sample No. 4 with a large amount of substitution, the low-temperature fired porcelain composition prepared with these glass compositions crystallized and the densification was hindered. The crystallized crystal phase is 2Al₂O₃・ B₂O₃Met.
[0052]
Sample numbers 1-6, 12, 15 are SiO₂Content is 68 mol% or more. Low-temperature fired porcelain compositions made with these glass compositions have particularly good plating resistance.
[0053]
(Example 2)
20 parts by weight of an acrylic resin binder and 100 parts by weight of a plasticizer (dibutyl phthalate) with respect to 100 parts by weight of mixed powder of 62% by volume of glass powder and 38% by volume of alumina filler in the glass composition ratios of Sample No. 5 and Sample No. 8 in Table 1. ) 10 parts by weight and 75 parts by weight of a solvent (mixed solution of toluene and isopropyl alcohol) were mixed to prepare a slurry. Next, a green sheet having a thickness of 250 μm was produced by a doctor blade method. A wiring layer is formed by pattern-printing Cu paste on the surface of the obtained green sheet by a screen printing method, and further, the green sheet is laminated so as to cover the formed wiring layer, and an unfired laminated body Formed. Thereafter, the non-fired laminate was degreased at 850 ° C. in a wet nitrogen atmosphere and fired at 1000 ° C. for 2 hours in a nitrogen atmosphere to obtain a wiring board.
[0054]
It was confirmed by visual observation that the wiring board formed in Example 2 was a wiring board without warping.
Thus, by using the low-temperature fired porcelain composition of the present invention for a wiring board, even if a wiring layer is formed from a material having a low resistivity and a low melting point such as Cu, the temperature range is 700 to 1050 ° C. Simultaneous firing is possible, and generation of warp of the wiring board is suppressed, and it can be adapted to a high-frequency signal. Further, boric acid crystals do not precipitate on the ceramic green sheet, and productivity can be improved.
[Brief description of the drawings]
FIG. 1 is a schematic cross-sectional view showing an embodiment of a wiring board according to the present invention.
[Explanation of symbols]
1 Wiring board
2 Substrate
3 Wiring layer

Claims (6)

When SiO ₂ , B ₂ O ₃ , Al ₂ O ₃ , and metal oxide RO are contained, and the total amount of SiO ₂ , B ₂ O ₃ , Al ₂ O ₃ , and RO is 100 mol%, the content of SiO ₂ There _68~72mol%, B 2 _O content of ₃ 14~ 22 mol%, 4~11mol% is content of _Al 2 _{O 3,} with the content of RO is 4~11mol%, SiO ₂ and B the total amount of the ₂ O ₃ is not more than 92 _mol%, a mol ratio of _B 2 _{O 3} and RO represented by B ₂ O 3 / RO is 1.3 to 4, R of the metal oxide RO is It consists of at least one component selected from Ca, Sr, Mg, and Zn, and when the total amount of the metal oxide RO is 100 mol%, CaO has a content of 60 mol% or more, an alkali metal, Pb , As and Sb Not including glass,
Including at least one inorganic filler of SiO ₂ or Al ₂ O ₃ ,
A low-temperature fired ceramic composition, wherein the glass content is 55 to 80% by volume and the inorganic filler content is 20 to 45% by volume . _{2. The} porcelain composition for low-temperature firing according to claim 1, wherein the glass has a molar ratio of Al ₂ O ₃ represented by RO / Al ₂ O ₃ and RO of greater than 1 and 2 or less.   The low-temperature fired porcelain composition according to claim 1 or 2, wherein the RO contains MgO as an essential component. The low-temperature fired ceramic according to any one of claims 1 to 3 , wherein the crystal phase contained after firing at 850 to 1050 ° C is only the crystal phase contained in the inorganic filler. Composition. 5. The low-temperature fired ceramic composition according to claim 4 , wherein the relative dielectric constant at 10 GHz is 7 or less, and the dielectric loss at 10 GHz is 0.003 or less. In a wiring board manufactured by simultaneously firing an insulator and a conductor at 850 to 1050 ° C, the insulator comprises the low-temperature fired ceramic composition according to any one of claims 1 to 5 , The wiring board, wherein the conductor is made of at least one selected from Ag, Au, and Cu.