JP6319947B2 - Ceramic wiring board - Google Patents

Description

  The present invention relates to a ceramic wiring board, and more specifically, a ceramic wiring board that can be fired simultaneously with a conductive paste containing Ag, has improved surface acid resistance and alkali resistance, and does not cause product defects due to deformation during firing. About.

  Conventionally, ceramic wiring boards that are used as electronic components and function as wiring boards for electric circuits are widely known. The ceramic wiring substrate is generally obtained from matrix-like glass and an inorganic filler formed of an inorganic compound. As the glass, a mixture containing silica and alumina as main components and further added an alkali metal oxide, an alkaline earth metal oxide or the like as a sintering aid can be used. As the inorganic filler, alumina, mullite, cordierite, titanium, zircon, forsterite, zirconia, quartz and the like are used.

  When manufacturing a ceramic wiring board, an organic binder, a plasticizer, and a solvent are mixed with powder, which is a mixture of glass and inorganic filler, to prepare a liquid mixture called slurry, and this mixture is then used as a doctor blade. It is formed into a sheet state (hereinafter sometimes referred to as “green sheet”) by a molding machine. Each green sheet is provided with a through-hole for constituting an electric circuit according to the pattern of the wiring board. The through hole of the green sheet is filled with a conductive paste containing a conductor, and the conductive paste is printed on the surface of the green sheet to form an electrode with the conductive paste. Furthermore, a plurality of green sheets filled with the conductive paste are stacked, and the laminate is fired. The fired laminate is a ceramic wiring board, and is used as an electronic component in which a conductor is three-dimensionally configured.

  In general, Ag is used as a conductor of a ceramic wiring board. The melting point of Ag is 962 ° C. When the firing temperature of the laminated green sheets is higher than the melting point of Ag, Ag in the filled conductive paste melts during firing and becomes fluidized and becomes unstable. The conductive paste in an unstable state causes a problem that the conductor is easily peeled after firing, or the conductor is deformed before and after firing. Therefore, the laminated green sheets need to be fired at about 900 ° C.

  In addition to being able to be fired at about 900 ° C., the fired ceramic wiring board has, as its properties, strong mechanical strength, low warpage due to heat, and excellent dielectric properties, Etc. are required. In order to satisfy these requirements at the same time, the composition or the composition ratio of the material of the ceramic wiring board has been variously adjusted. Specifically, various additive elements have been added to the glass, and the constituent ratio between the glass and the inorganic filler has been adjusted.

  For example, Patent Document 1 states that “a low-resistance conductor such as an Ag-based metal and a Cu-based metal can be simultaneously fired at 1000 ° C. or less, has high mechanical strength, and warps in the obtained sintered body. It is an object to provide a dielectric porcelain with a small amount (there is little warpage, which improves dimensional stability and can suppress transmission loss even when used in the GHz band) (see paragraph No. 0004 of Patent Document 1). ), "When the inorganic filler and glass are contained, and the total of the inorganic filler and glass is 100% by mass, the inorganic filler is contained at 20 to 60% by mass, the glass is contained at 40 to 80% by mass, When the total glass is 100% by mass, the Si is 20 to 30% by mass, the B is 5 to 30% by mass, the Al is 20 to 30% by mass, and the Ca is calculated in terms of oxides. 10 to 20 mass , The Zn containing 10 to 20 wt%, and, Li, (see claim 1 of Patent Document 1) dielectric ceramic "which is characterized by not containing Na and K are disclosed.

  Patent Document 2 discloses a dielectric ceramic that can be sintered simultaneously with a low-resistance conductor such as an Ag-based metal and a Cu-based metal, has excellent mechanical strength, and exhibits excellent dielectric characteristics in the GHz band. “Providing” (see paragraph No. 0005 of Patent Document 2), “When the inorganic filler and glass are contained, and the total of the inorganic filler and the glass is 100 mass%, the inorganic filler 20 to 60% by mass, 40 to 80% by mass of the glass, and when the total glass is 100% by mass, each of the glasses is equivalent to 20 to 30% by mass of Si and B in terms of oxide. 5 to 30% by mass, Al 20 to 30% by mass, Ca 10 to 20% by mass, Zn 10 to 20% by mass, Li, Na, and K at least one alkali metal in total 0.2 It is characterized by containing ~ 5% by mass That dielectric ceramic "(see claim 1 of Patent Document 2) are disclosed.

  Patent Document 3 provides “a dielectric ceramic that can be fired simultaneously with a low-resistance conductor such as an Ag-based metal and a Cu-based metal, has excellent mechanical strength, and exhibits excellent dielectric properties in the GHz band. (See paragraph No. 0005 of Patent Document 3), “a dielectric ceramic made by firing a composition for a dielectric ceramic containing an inorganic filler and glass at 1000 ° C. or less, The dielectric ceramic composition contains 20 to 60% by mass of the inorganic filler and 40 to 80% by mass of the glass when the total amount of the inorganic filler and the glass is 100% by mass. Furthermore, when the total glass is 100% by mass, the glass is 20 to 30% by mass of Si, 5 to 30% by mass of B, 20 to 30% by mass of Al, and Ca in terms of oxide. Is 10 to 20% by mass, Zn is 1 Dielectric porcelain characterized in that it contains 0.2 to 5 mass% in total of at least one alkali metal of ˜20 mass%, Li, Na, and K (see claim 1 of Patent Document 3) ) Is disclosed.

  Patent Document 4 provides “a dielectric ceramic that can be fired simultaneously with a low-resistance conductor such as an Ag-based metal and a Cu-based metal, has excellent mechanical strength, and exhibits excellent dielectric properties in the GHz band. (Refer to paragraph No. 0005 of Patent Document 4), “a dielectric ceramic made by firing a composition for a dielectric ceramic containing an inorganic filler and glass at 1000 ° C. or less, The dielectric ceramic composition contains 20 to 60% by mass of the inorganic filler and 40 to 80% by mass of the glass when the total amount of the inorganic filler and the glass is 100% by mass. Furthermore, when the total glass is 100% by mass, the glass is 20 to 30% by mass of Si, 5 to 30% by mass of B, 20 to 30% by mass of Al, and Ca in terms of oxide. Is 10 to 20% by mass, Zn is 1 It contained 20 wt%, and, Li, Na and K dielectric ceramic, characterized in that not contained "(see claim 1 of Patent Document 4) are disclosed.

In Patent Document 5, “Providing a ceramic composition suitable for multilayer wiring boards, particularly capable of firing at an extremely low temperature of 1000 ° C. or lower” (page (2) of Patent Document 5, upper left column, line 19 to Upper right column, first line), “Glass frit is essentially by weight percent SiO ₂ 25-40, Al ₂ O ₃ 4-15, B ₂ O ₃ 15-25, BaO + CaO + MgO 15-40, ZnO 1-10, ZrO ₂ 0 A composition for ceramic substrate according to claim 1 (refer to claim 2 of patent document 5) comprising .5 to 5.

  The surface of the fired ceramic wiring substrate is generally subjected to plating treatment with Ni or Ni and Au in order to protect the conductor portion obtained by sintering the conductive paste. Before the plating process, it exists on the surface of the ceramic wiring board by a strong acid or strong alkaline pretreatment liquid used for the purpose of removing glass or the like on the conductor surface, or an acidic or alkaline plating liquid itself. If the glass is eluted, it is not preferable due to a decrease in strength of the ceramic wiring board itself, a decrease in adhesion of the surface conductor, and generation of foreign matters in the subsequent component mounting process. Therefore, the surface of the ceramic wiring board needs to have resistance to a strong acid solution or a strong alkaline solution (hereinafter, sometimes referred to as “chemical resistance”). Patent Documents 1 to 5 do not describe or suggest chemical resistance on the surface of the ceramic wiring board.

Further, when firing a multilayer green sheet, the temperature in the firing furnace is not exactly uniform. For example, even if firing at 870 ° C. is intended, the temperature in the firing furnace varies by about 850 ° C. to 900 ° C. depending on the location. Depending on the temperature conditions, the shrinkage rate of the substrate itself may vary, resulting in large variations in the finished dimensions, resulting in product defects. Specifically, when the finished dimensions of the ceramic wiring board are greatly different, an appropriate amount of solder may be formed at a predetermined position when printing solder used for mounting electronic components such as chip capacitors. It becomes difficult and cannot be attached to the surface of the ceramic wiring board. Therefore, in order to prevent defective products of the ceramic wiring board, it is preferable that no significant difference is observed in the dimensional change of the green sheet due to different firing temperatures.
However, Patent Documents 1 to 5 do not describe or suggest a difference in dimensional change of the green sheet due to a difference in temperature conditions.

JP 2003-115218 A JP 2003-115217 A JP 2003-112971 A JP 2003-112972 A JP-A-60-235744

  The present invention can be fired together with a conductive paste containing Ag, and the surface has chemical resistance, so that surface erosion can be prevented by an acid or alkali solution of the plating pretreatment liquid and the plating liquid itself, An object of the present invention is to provide a ceramic wiring board in which a difference in dimensional change of a green sheet due to a temperature difference during firing is small, and product defects due to deformation during firing are small.

Means for solving the problems of the present invention are as follows:
(1) In the ceramic wiring board containing an inorganic filler and glass, the glass is amorphous, and the glass is made of SiO ₂ , Al ₂ O ₃ , B ₂ O ₃ , ZnO, CaO, Na ₂ O, And K ₂ O, and the ratio of the amount of the constituent components present in the glass is such that SiO ₂ is 49 to 54 mol% and Al ₂ O ₃ is 8 to 13 mol% with respect to the entire glass. Yes, the total of Na ₂ O and K ₂ O is greater than 0.2 mol% and less than or equal to 2 mol%, and the molar ratio of SiO ₂ present in the glass to the total of CaO and ZnO is SiO ₂ / (CaO + ZnO)> 2.0 was filled, _MgO, it does not contain ZrO 2, PbO, and Li ₂ O, a ceramic wiring board characterized by.

  According to this invention, since the increase in the softening point of the glass can be suppressed, it is possible to co-fire with the conductive paste containing Ag, and the chemical resistance of the sheet surface can be increased. Is not eroded, and the difference in dimensional change of the green sheet due to the temperature difference during firing is small, so that it is possible to provide a ceramic wiring board capable of reducing product defects.

  The ceramic wiring board according to the present invention contains glass and an inorganic filler as main components.

  The glass exists in an amorphous state in the ceramic wiring substrate. Therefore, even if the ceramic wiring substrate formed of amorphous glass is fired at a temperature of 1000 ° C. or lower, the glass contained in the ceramic wiring substrate does not crystallize. The particle size of the amorphous glass powder is not particularly limited as long as it can be uniformly mixed with the filler powder, which will be described later, and the mixed powder can be molded, and can be sintered sufficiently densely by low-temperature firing. Is usually about 1.0 to 5.0 μm.

The glass can change the firing temperature of the green sheet depending on the composition and content thereof. The _{glass, SiO 2, Al 2 O 3} , B 2 O 3, ZnO, CaO, containing _Na 2 O, and _{K 2} O. When the entire glass is 100, the content of each of these constituents, SiO ₂ is 49 to 54 mol%, _Al 2 _{O 3} 8 to 13 mol%, preferably from 8.2 to 13 mol% The total of Na ₂ O and K ₂ O is more than 0.2 mol% and 2 mol% or less, preferably 1 mol or more and 2 mol or less.

When the amount of SiO ₂ present in the glass is less than 49 mol%, the chemical resistance on the surface of the ceramic wiring substrate is deteriorated. On the other hand, if the amount of SiO ₂ present in the glass exceeds 54 mol%, the softening point of the glass increases, so the temperature required for firing the ceramic wiring substrate increases, and simultaneous firing with the conductive paste containing Ag is possible. It becomes difficult.

When the amount of Al ₂ O ₃ present in the glass is less than 8 mol%, the mechanical strength of the ceramic wiring board cannot be sufficiently obtained, and further, the stability of the glass is impaired. On the other hand, if the amount of Al ₂ O ₃ present in the glass exceeds 13 mol%, the temperature at which firing can be increased, and vitrification will not occur.

If the total amount of Na ₂ O and K ₂ O present in the glass is less than 0.2 mol%, the softening point of the glass increases, so the temperature required for firing the ceramic wiring substrate increases, and Ag Co-firing with a conductive paste containing is difficult. When the total amount of Na ₂ O and K ₂ O present in the glass exceeds 2 mol%, the chemical resistance on the surface of the ceramic wiring substrate is deteriorated and the insulating properties of the glass are deteriorated.

B ₂ O ₃ is present in the glass. The content of B ₂ O ₃ is appropriately determined so that the total of SiO ₂ , Al ₂ O ₃ , B ₂ O ₃ , ZnO, CaO, Na ₂ O, and K ₂ O in the glass is 100 mol%. The Preferably, the amount of _B 2 _{O 3} present in the glass is 9-18 mol%. If B ₂ O ₃ is too small, the temperature at which sintering can be performed becomes too high, and co-firing with a conductive paste containing Ag becomes impossible, which is not preferable. On the other hand, an excessive amount of B ₂ O ₃ is not preferable because the chemical stability of the glass is lowered and the chemical resistance of the surface of the ceramic wiring board cannot be sufficiently obtained.

The molar ratio of SiO ₂ present in the glass to the total of CaO and ZnO satisfies SiO ₂ /(CaO+ZnO)>2.0. If the Ca content is too small, the meltability of the glass will not be improved sufficiently, and co-firing with the conductive paste containing Ag will be difficult, and if the Ca content is excessive, the thermal expansion of the green sheet will occur. The coefficient increases and may cause product defects. Further, if the Zn content is too small, the co-firing property with the conductive paste containing Ag is not sufficient, and the green sheet is warped. On the other hand, if the Zn content is excessive, the surface of the ceramic wiring board Insufficient chemical resistance can be obtained. The composition ratio of SiO ₂ , CaO, and ZnO in the glass is adjusted so as to satisfy the above formula, so that the chemical resistance of the surface of the ceramic wiring board is good and co-firing with the conductive paste containing Ag. Is possible.

  MgO is not contained in the glass in this invention, in other words, MgO is not substantially contained in the glass. That is, MgO is inevitably included as an impurity in the glass production process, but MgO is not intentionally added as a component of the glass. When MgO is contained in the glass, crystals such as mullite may be precipitated in the glass during the firing of the green sheet. Therefore, the chemical resistance on the surface of the ceramic wiring board is deteriorated by the composition of the glass that has not been crystallized. The content of MgO as an unavoidable impurity can be allowed to the extent that crystals do not precipitate in the glass. For example, MgO is preferably less than 0.2 mol% with respect to the entire glass.

ZrO ₂ is not contained in the glass in the present invention, in other words, ZrO ₂ is not substantially contained in the glass. That is, ZrO ₂ is inevitably contained as an impurity in the glass production process, but ZrO ₂ is not intentionally added as a constituent of glass. When ZrO ₂ is contained in the glass, ⁹⁶ Zr, which is a radioisotope contained in ZrO ₂ , is inevitably contained in the glass, and a very small amount of radiation emitted by ⁹⁶ Zr is generated in the ceramic wiring board. Since it may cause malfunction, it is not preferable.

  PbO is not contained in the glass in the present invention, in other words, PbO is not substantially contained in the glass. That is, PbO is inevitably contained as an impurity in the glass production process, but PbO is not intentionally added as a component of the glass. Since Pb is a substance that is toxic to the human body and is subject to emission control, it is not preferable to add it as a constituent component of glass.

Li ₂ O is not contained in the glass in the present invention, in other words, Li ₂ O is not substantially contained in the glass. In other words, Li ₂ O is inevitably contained as an impurity in the glass production process, but Li ₂ O is not intentionally added as a constituent of the glass. If Li ₂ O is contained in the glass, the conductor Ag may ooze out into the ceramic and cause insulation failure.

  The inorganic filler can change dielectric properties and mechanical properties depending on the type and content thereof. Examples of the inorganic compound forming the inorganic filler include garnite, titania, alumina, titanate (magnesium titanate, calcium titanate, strontium titanate, barium titanate, etc.), mullite, zirconia, quartz, cordierite, Examples include forsterite, wollastonite, anorthite, enstatite, diopsite, akermanite, gelenite, and spinel. Among these, garnite, titania, zirconia, and alumina are particularly preferable. These inorganic compounds can be used alone or in combination of two or more inorganic compounds.

  Moreover, the shape of an inorganic filler is not specifically limited, For example, it may be various shapes, such as a particulate form, a scale top, and a fibrous form, and is a particulate form normally. Further, the size is not particularly limited, but usually the size is preferably 1 to 10 μm (average particle diameter in the case of a particle shape). If it exceeds 10 μm, the structure of the dielectric ceramic tends to be excessively rough. If the thickness is less than 1 μm, it may be difficult to produce the ceramic wiring substrate. Incidentally, the inorganic filler is usually present in the ceramic wiring board with the shape and size added at the time of manufacture.

The inorganic filler contains 20 to 60% by mass, preferably 30 to 60% by mass, more preferably 40 to 55% by mass, when the total of the inorganic filler and glass is 100% by mass. Contained. If the content of the inorganic filler is less than 20% by mass, the glass may be reacted with the firing jig, and it may be difficult to obtain a sufficient bending strength. On the other hand, if it exceeds 60 mass%, firing at 1000 ° C. or lower may be difficult, and simultaneous firing with a conductive paste containing Ag may not be performed.

The outer diameter dimension change rate in the ceramic wiring board is obtained by the following expression.
Outside diameter dimensional change rate = (outside diameter dimension at 900 ° C.−outside diameter dimension at 860 ° C.) / Outside diameter dimension at 860 ° C. The “outside diameter dimension” is the opposing distance of four corners in a rectangle. And the length of one side in the horizontal direction (X direction) or the length of one side in the vertical direction (Y direction) on the rectangular ceramic wiring board surface. The outer diameter of 900 ° C. is the outer diameter of the ceramic wiring board measured after firing at 900 ° C., and the outer diameter of 860 ° C. is the ceramic wiring measured after firing at 860 ° C. It is the outer diameter of the substrate. The lengths of the four sides of the rectangular ceramic wiring board are respectively calculated by substituting them into the above formulas, and the values of the four outer diameter dimensional change rates are obtained. The strain on the surface of the ceramic wiring board is evaluated by the average value of the four outer diameter dimensional change rates.
By reducing the difference in outer diameter that has changed at different temperatures, each of the multi-layered green sheets can suppress variations in thermal deformation due to differences in firing temperature, and distortion on the surface of the ceramic wiring board is reduced. If the average value of the dimensional change rate of the outer diameter is 2.0 or less, the distortion on the surface of the ceramic wiring board should be reduced to the extent that electronic components such as chip capacitors can be mounted on the surface of the ceramic wiring board. Can do. Therefore, product defects can be reduced.

The ceramic wiring board according to the present invention is not particularly limited, but can be manufactured as follows.
First, raw material powder is prepared. Specifically, SiO ₂ powder, B ₂ O ₃ powder, Al ₂ O ₃ powder, ZnO powder, CaO powder, Na ₂ O powder and K ₂ O powder are mixed. The ratio of each raw material powder is ₄ to 54 mol% for SiO _{2 and 8} to 13 mol% for Al ₂ O ₃ with respect to the entire raw material powder, and the total of NaO ₂ and K ₂ O is 0.2 mol%. It is larger and is 2 mol% or less. Regarding SiO ₂ , CaO and ZnO, the molar ratio of SiO ₂ to the total of CaO and ZnO in the raw material powder satisfies SiO ₂ /(CaO+ZnO)>2.0. The B ₂ O _3, as _SiO 2 in the raw material _{powder, Al 2 O 3, B 2} O 3, ZnO, CaO, Na 2 O, and _{K 2} O Total is 100 _{mol%, B} 2 O _Although the content of ₃ is appropriately determined, the amount of B ₂ O ₃ included in the raw material powder is usually 9 to 18 mol%. In the present invention, MgO, ZrO ₂ , PbO and LiO ₂ are not included in the raw material powder.
The raw material powder obtained by mixing is heated and melted, and then rapidly cooled to form a frit. By pulverizing the frit, a glass powder can be obtained.
Although there is no restriction | limiting in particular about the particle size of glass powder, Usually, it is preferable that it is 1-10 micrometers. If the particle size of the glass powder exceeds 10 μm, it may hinder the formation of a green sheet containing an inorganic filler and glass. If the particle size of the glass powder is less than 1 μm, the frit is crushed. The processing time becomes long and inefficient, and it may cause difficulty in handling.
Next, the glass powder and the inorganic filler are mixed. The mixing operation can be performed using various mixers such as a ball mill. As for the compounding ratio of the glass powder and the inorganic filler, the inorganic filler is 30 to 60% by mass, preferably 40 to 50% by mass, and the glass powder is 40 to 70% by mass, preferably 45 to 60% by mass.
The composition for a wiring board obtained by mixing the glass powder and the inorganic filler may be a composition comprising the glass powder and the inorganic filler, and together with the glass powder and the inorganic filler, a binder, a solvent, a plastic An agent, a dispersant and the like may be contained.
As the binder, polyolefin resins such as polyvinyl butyral, methacrylic resins such as acrylic resin and methacrylic resin, and the like can be used. As solvents, aromatic solvents such as benzene, toluene and xylene, and alcohols and ketones. Examples of the plasticizer include dialkyl carboxylates such as dioctyl phthalate and dibutyl phthalate, and polyethylene glycol.
The wiring board composition is formed into a sheet, prepared into a predetermined shape, and then dried at an appropriate temperature of 60 to 80 ° C. to form a green sheet. In this way, a plurality of types of green sheets are formed. The thickness of the green sheet is usually 0.025 to 0.200 mm.
Among a plurality of types of green sheets, in a predetermined green sheet, a through-hole penetrating from one surface of the green sheet to the other surface is opened by laser processing. The diameter of the through hole is not particularly limited, but is usually 75 to 150 μm.
A conductor pattern having a predetermined pattern is formed on the plane of the green sheet having the through hole so as to cover the through hole. The conductor pattern can be formed by filling the through hole with a conductive paste containing Au, Ag—Pd, Ni, Cu or the like.
A laminated sheet is formed by laminating green sheets on which conductor patterns are formed.
The laminated sheet is usually fired at 850 to 900 ° C., and after firing, a ceramic wiring board is obtained.
The fired ceramic wiring board is composed of a plurality of layers. Of the ceramic wiring substrate, the outermost layer is exposed to a surface (referred to as an outer surface) opposite to a surface (referred to as an inner surface) in contact with another adjacent layer. In order to improve solder corrosion resistance and solder wettability in the conductor, for example, Ni is used, or plating is performed using Ni and Au. Before performing the plating treatment, the surface is etched using an acidic solution or an alkaline solution for the purpose of easily depositing the plating on the conductor surface of the ceramic wiring substrate surface. In order to perform the plating treatment, for example, an electroplating method or an electroless plating method may be used.
In the ceramic wiring board according to the present invention, since the chemical resistance is excellent, surface etching before plating can be performed without adversely affecting the conductor surface and the board itself.

Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples.
(1) Preparation of glass powder SiO ₂ powder, B ₂ O ₃ powder, Al ₂ O ₃ powder, ZnO powder, CaO powder, Na ₂ O powder, K ₂ O powder were mixed at the ratio shown in Table 1. Raw material powder was prepared. After the obtained raw material powder was melted by heating, it was poured into water, rapidly cooled and ground with water to obtain a glass frit. This glass frit was further pulverized by a ball mill to obtain 18 kinds of glass powder having an average of 3 μm.

(2) Production of Green Sheet The glass powder prepared in the above (1) and the alumina powder that is an inorganic filler are weighed so as to have a ratio of 50% by mass and mixed in a ball mill to obtain a mixed powder. Obtained. To the obtained mixed powder, an acrylic resin as a binder, dibutyl phthalate (DBP) as a plasticizer, and toluene as a solvent were added and mixed to obtain a slurry. Slurries were prepared from each of 18 kinds of glass powders, and 18 kinds of slurries were obtained. Each slurry was formed into a sheet shape by a doctor blade method so that the thickness after firing was 100 μm, and 18 types of green sheets were obtained.

(3) Preparation of conductive paste Ag powder and Pd powder were weighed so as to have a ratio of 85% by mass to 0.5% by mass, respectively, and mixed by a ball mill to obtain a mixed powder. To the obtained mixed powder, an ethyl cellulose resin as a binder and tervineol as a solvent were added and mixed to obtain a conductive paste.

(4) Filling with conductive paste Each of the 18 types of green sheets obtained in (2) above was subjected to laser processing, and through-holes were punched at predetermined positions so that the cross-section was a circle with a diameter of 100 μm. After the conductive paste was filled in the position of the through hole of each green sheet (3), a conductor pattern was formed to a thickness of 15 μm using a screen printing method.

(5) Stacking and firing of green sheets For a plurality of green sheets, the same type of green sheets were stacked after filling the conductive paste and forming the conductive pattern in the same manner as in (4) above. The laminated green sheets were pressure-bonded at a pressure of 1000 kgf / cm 2 and cut into rectangles of a predetermined size to obtain an unfired ceramic laminate. The unfired ceramic laminate was fired at 860 ° C. or 900 ° C. for 1 hour. After firing, a ceramic wiring substrate was obtained in which an electric circuit made of a conductive paste was formed in a predetermined pattern between the layers of the green sheet.

(6) Calculation of dimensional change in outer diameter For ceramic wiring boards made of the same kind of glass powder composition, in the case of firing at 860 ° C. and firing at 900 ° C. in the above (5), The total length of four sides, ie, two sides in the direction (X direction) and two sides in the vertical direction (Y direction), was measured using a caliper. The measured values of the lengths of the four sides were the outer diameter dimension of 860 ° C. and the outer diameter dimension of 900 ° C. The measured values of the lengths of these four sides were substituted into the following calculation formula, and the calculation result was taken as the outer diameter dimensional change rate, and the average value of the four side outer diameter dimensional change rates was calculated. The results are shown in Table 2.
The outer diameter dimension change rate = (900 ° C. with an external diameter of -860 outer diameter of ° C.) / 860 ° C. of outer diameter

(7) Evaluation of crystallinity About the ceramic wiring board after baking, crystallinity was determined using the X-ray-diffraction apparatus. When the diffraction pattern of only the filler (alumina in this example) to which the obtained diffraction peak is added is obtained, it is determined that the glass in the ceramic wiring substrate exists as an amorphous state, and it is caused by the other crystal layers. When the diffraction pattern to be obtained was obtained, it was determined that the glass in the ceramic wiring substrate was present as a crystalline material.

(8) Evaluation of firing stability with conductive paste During the firing operation in (5) above, whether or not the ceramic material and the conductive paste can be fired simultaneously was evaluated based on the following criteria. First, “◯” indicates that simultaneous firing is possible and the conductive paste adheres without problems after firing. Next, although simultaneous sintering is possible, it was set as "(triangle | delta)" that a conductive paste part peels after baking or a conductive paste part deform | transforms compared with before sintering. Finally, “X” indicates that the temperature required for firing the glass is high and the simultaneous firing with the conductive paste cannot be performed. The results are shown in Table 2 below.

(9) Evaluation of chemical resistance on the surface of the ceramic wiring board The fired ceramic wiring board was immersed in 1N KOH or 1N HCl and stirred at room temperature for 15 minutes using a stirrer. The weight of the ceramic wiring board before and after the immersion was measured, and the reduction rate of the weight after immersion with respect to the weight before immersion was calculated. Even when immersed in either KOH solution or HCl solution, “◯” was given when the reduction rate was 0.1% or less. When immersed in at least one of the KOH solution and the HCl solution, “x” was given when the reduction rate was greater than 0.1%. The results are shown in Table 2.

  The glass compositions used in the examples and comparative examples are shown in Table 1 below.

  Table 2 shows the average value of the dimensional change rate of the four sides of the ceramic wiring boards manufactured in Examples and Comparative Examples, the crystallinity of the glass, the firing stability, and the chemical resistance.

  Comparative Examples 1 to 3 and 7 to 10 all had poor chemical resistance on the surface of the ceramic wiring board, and significant weight reduction was observed with an acidic solution or a basic solution. In Comparative Examples 5 to 6, 8, and 10, firing stability was poor, and simultaneous firing with a conductive paste containing Ag was impossible, or conductor peeling and deformation occurred after simultaneous firing. In Comparative Example 4, the outer diameter changes greatly between the firing at 900 ° C. and the firing at 860 ° C., and it is impossible to mount electronic components such as chips on the surface of the ceramic wiring board. Produced. On the other hand, in Examples 1 to 8 according to the present invention, all show good chemical resistance, good firing stability with the conductive paste, the rate of change in the outer diameter due to temperature difference is small, and product failure A ceramic wiring board that does not cause the problem was obtained.

Claims (1)

In ceramic wiring board containing inorganic filler and glass,
The glass is amorphous;
The glass _{contains SiO 2, Al 2 O 3,} B 2 O 3, ZnO, CaO, Na 2 O, and _{K 2} O,
The ratio of the amount of the constituent components present in the glass is such that SiO ₂ is 49 to 54 mol%, Al ₂ O ₃ is 8 to 13 mol%, Na ₂ O and K ₂ with respect to the entire glass. The total with O is more than 0.2 mol% and 2 mol% or less,
The molar ratio of SiO ₂ present in the glass to the total of CaO and ZnO satisfies SiO ₂ /(CaO+ZnO)>2.0,
A ceramic wiring board characterized by not containing MgO, ZrO ₂ , PbO, and Li ₂ O.