JP2007258384A - Glass ceramic sintered material, manufacturing method therefor, wiring board, and manufacturing method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wiring board and a manufacturing method therefor which prevent an insulation failure due to migration even if the thickness size of an insulation layer is small. <P>SOLUTION: The wiring board 1 is composed of alternately laminated insulation layers 2 and wiring layers 3. The insulation layer 2 is made of a glass ceramic sintered material, and is obtained by sintering a compact containing glass powder and ceramic powder and depositing at least one kind of a crystal phase from the glass powder during sintering. Voids present inside the insulation layer 2 shows a maximum diameter of 2 μm or more to 4 μm or less, and a void area occupation rate in section of 1.0% or more to 2.5% or less. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a glass ceramic sintered body that can be used as an insulating layer and a method for producing the same.

  The present invention also relates to a wiring board whose insulating layer is made of a glass ceramic sintered body and a method for manufacturing the same.

In recent years, IC (Integrated Circuit) and LSI (Large Scale) have been highly integrated.
2. Description of the Related Art A wiring board applied to a semiconductor element housing package on which a semiconductor element such as an integration) is mounted, a hybrid integrated circuit device on which various electronic components are mounted, or the like is required to have high density and small size and light weight. In response to such demands for higher density and smaller size and weight, the thickness dimension of each insulating layer constituting the wiring board has shifted to thinner, particularly in terms of reducing the height of the wiring board. The insulating layer needs to be configured with a thickness dimension of 100 μm or less (see, for example, Patent Documents 1 to 3).

JP 2001-111218 A Japanese Patent Laid-Open No. 10-93238 JP-A-7-154073

When the insulating layer becomes thin in this way, if the insulating layer is insufficiently dense, migration due to liquids such as water and plating solution that have penetrated into the voids present inside the insulating layer occurs. The specific resistance is less than 10 ¹¹ Ω · cm, which causes a problem that a short circuit occurs between the two wiring layers sandwiching the insulating layer.

  The objective of this invention is providing the glass-ceramic sintered compact which can prevent the insulation defect by migration, even if the thickness dimension is small, and its manufacturing method.

  Another object of the present invention is to provide a wiring board that can prevent insulation failure due to migration even if the thickness dimension of the insulating layer is small, and a method for manufacturing the same.

The present invention is a glass ceramic sintered body obtained by firing a molded body containing glass powder and ceramic powder, and precipitating at least one crystal phase from the glass powder during firing,
The glass ceramic sintered body is characterized in that the maximum diameter of voids present therein is 2 μm or more and 4 μm or less, and the void area occupation ratio in the cross section is 1.0% or more and 2.5% or less.

  The present invention is also the wiring board characterized in that the insulating layers made of the glass ceramic sintered body and the wiring layers are alternately laminated.

  According to the present invention, the minimum distance between the wiring layers is 5 μm or more and 20 μm or less.

Further, the present invention is a method for producing a glass ceramic sintered body by firing a molded body containing glass powder and ceramic powder, and depositing at least one crystal phase from the glass powder during firing,
A method for producing a sintered glass ceramic, wherein the ratio A (= ρ2 / ρ1) of the density ρ2 of the crystal phase to the density ρ1 of the glass powder is 1.00 or more and 1.15 or less. .

  In addition, the present invention is characterized in that an average particle diameter D50 of each of the glass powder and the ceramic powder is 1 μm or more and 2 μm or less.

Further, according to the present invention, the particle size distribution of the glass powder and the ceramic powder is such that the cumulative particle size of 10% from the fine particle side of the number cumulative distribution is D10, and the cumulative particle size of 50% from the fine particle side of the number cumulative distribution is D50. And when the particle size of 90% cumulative from the fine particle side of the cumulative number distribution is D90,
0.7 ≦ (D90−D10) / D50 ≦ 2
It is characterized by satisfying.

Further, the present invention is a method of manufacturing a wiring board configured by alternately laminating insulating layers and wiring layers,
A method for manufacturing a wiring board, wherein the insulating layer is formed using the method for manufacturing the glass ceramic sintered body.

  According to the present invention, the glass ceramic sintered body is obtained by firing a glass powder and a molded body containing the ceramic powder and precipitating at least one crystal phase from the glass powder during firing. In the glass-ceramic sintered body, the maximum diameter of voids existing inside is 2 μm or more and 4 μm or less, and the void area occupation ratio in the cross section is 1.0% or more and 2.5% or less. In such a glass ceramic sintered body, even if the thickness dimension is small, for example, about 20 μm, it is possible to prevent the occurrence of migration due to the liquid that has entered the void inside the glass ceramic, and to prevent insulation failure due to migration. it can.

  It is extremely difficult to make the maximum diameter of the void less than 2 μm, and in order to realize this, the equipment becomes complicated and the manufacturing cost increases. When the maximum diameter of the void exceeds 4 μm, the above-described effect cannot be obtained. It is extremely difficult to make the void area occupation rate less than 1.0%, and in order to realize this, the facilities become complicated and the manufacturing cost increases. If the void area occupancy exceeds 2.5%, the above-described effects cannot be obtained.

  According to the present invention, the insulating substrate and the wiring layer are alternately laminated to constitute the wiring board. In this wiring board, since the insulating layer is made of a highly dense glass ceramic sintered body as described above, even if the thickness of the insulating layer is small, for example, about 20 μm, the occurrence of migration is prevented. Thus, insulation failure due to migration can be prevented.

  According to the present invention, since the minimum distance between the wiring layers is 5 μm or more and 20 μm or less, it is possible to reduce the thickness dimension of the wiring board as much as possible while preventing insulation failure due to migration. If the minimum distance between the wiring layers is less than 5 μm, migration occurs and insulation failure due to migration occurs. If the minimum distance between the wiring layers exceeds 20 μm, the effect of reducing the thickness dimension of the wiring board as much as possible cannot be obtained sufficiently.

  Further, according to the present invention, a molded body containing glass powder and ceramic powder is fired, and at least one crystal phase is precipitated from the glass powder during firing, thus obtaining a glass ceramic sintered body. . In the present invention, the ratio A (= ρ2 / ρ1) of the density ρ2 of the crystal phase to the density ρ1 of the glass powder is 1.00 or more and 1.15 or less. Therefore, by reducing the difference between the volume occupied by the glass powder in the molded body and the volume occupied by the crystal phase in the sintered body, voids generated inside the glass ceramic sintered body due to this volume difference, specifically, Fine voids having a maximum diameter of less than 5 μm can be significantly reduced. As a result, it is possible to realize a glass ceramic sintered body that can prevent insulation failure due to migration even if the thickness dimension is small. When the ratio A exceeds 1.15, the above-described effects cannot be obtained.

  According to the present invention, since the average particle diameter D50 of the glass powder is 1 μm or more and 2 μm or less and the average particle diameter D50 of the ceramic powder is 1 μm or more and 2 μm or less, However, it easily penetrates into the gaps between the solid phase particles. Therefore, rearrangement of the solid phase particles easily occurs due to the flow of the liquid phase, and the packing of the solid phase particles becomes dense and densified. As a result, generation of voids corresponding to voids between the solid phase particles can be suppressed. It is difficult to prepare glass powder and ceramic powder having an average particle diameter D50 of less than 1 μm. If such glass powder and ceramic powder are used, the production cost increases. If at least one of the glass powder and the ceramic powder has an average particle diameter D50 of more than 2 μm, the above-described effects cannot be obtained.

  According to the present invention, a glass powder having a particle size distribution satisfying the formula 0.7 ≦ (D90−D10) / D50 ≦ 2 is used, and the formula 0.7 ≦ (D90−D10) / D50 ≦ 2 is used. Since the ceramic powder having a particle size distribution satisfying the above is used, the liquid phase of the glass powder easily penetrates into the gaps between the solid phase particles during the sintering process. Therefore, rearrangement of the solid phase particles easily occurs due to the flow of the liquid phase, and the packing of the solid phase particles becomes dense and densified. As a result, generation of voids corresponding to voids between the solid phase particles can be suppressed. It is difficult to prepare a glass powder and a ceramic powder having (D90-D10) / D50 of less than 0.7, and the use of such a glass powder and a ceramic powder increases the manufacturing cost. When (D90-D10) / D50 exceeds 2 for at least one of glass powder and ceramic powder, the above-described effects cannot be obtained.

  Further, according to the present invention, a wiring board configured by alternately laminating insulating layers and wiring layers is manufactured. Since the insulating layer of this wiring board is formed using the method for manufacturing a glass ceramic sintered body as described above, voids generated inside the insulating layer can be reduced. Therefore, even if the thickness dimension of the insulating layer is small, it is possible to realize a wiring board that prevents insulation failure due to migration.

  FIG. 1 is a cross-sectional view showing a configuration of a wiring board 1 according to an embodiment of the present invention. The wiring board 1 of the present embodiment is configured by alternately laminating insulating layers 2 and wiring layers 3. A stacked body formed by stacking a plurality of insulating layers 2 serves as an insulating substrate. The insulating layer 2 has a thickness dimension of about 5 μm to 20 μm and is made of a glass ceramic sintered body. The wiring layer 3 has a thickness dimension of about 5 μm to 20 μm and is made of a metal conductor. The insulating layer 2 is provided with a via-hole conductor 4 having a diameter of about 80 μm to 200 μm that penetrates the insulating layer 2 in the thickness direction. Each wiring layer 3 is electrically connected by the via-hole conductor 4 to form a predetermined electric circuit. An electrical element 5 such as a semiconductor element is mounted on such a wiring board 1.

  The insulating layer 2 is obtained by firing a molded body containing glass powder and ceramic powder and precipitating at least one crystal phase from the glass powder during firing.

  Insulating layer 2 has a maximum void diameter of 2 μm or more and 4 μm or less, preferably 2 μm or more and 3 μm or less, and more preferably 2 μm or more and 2.5 μm or less. The insulating layer 2 has a void area occupation ratio in a cross section of 1.0% or more and 2.5% or less, preferably 1.0% or more and 2.0% or less, more preferably 1.0% or more. 1.5% or less.

As described above, the insulating layer 2 has a maximum void diameter of 2 μm or more and 4 μm or less and a void area occupancy in the cross section of 1.0% or more and 2.5% or less. A sufficient volume can be secured. In such an insulating layer 2, even if the thickness dimension is about 20 μm, it is possible to prevent migration due to the liquid that has entered the void inside. Since the occurrence of migration is prevented in this way, insulation failure due to migration can be prevented. Even if the thickness dimension of the insulating layer 2 is about 20 μm, the specific resistance becomes 10 ¹¹ Ω · cm or more. The specific resistance of the insulating layer 2 refers to the specific resistance between both surfaces of the insulating layer 2.

  It is extremely difficult to make the maximum diameter of the void less than 2 μm, and in order to realize this, the equipment becomes complicated and the manufacturing cost increases. When the maximum diameter of the void exceeds 4 μm, the above-described effect cannot be obtained. It is extremely difficult to make the void area occupation rate less than 1.0%, and in order to realize this, the facilities become complicated and the manufacturing cost increases. If the void area occupancy exceeds 2.5%, the above-described effects cannot be obtained.

  Since the wiring board 1 has the insulating layer 2 as described above, even if the minimum distance between the wiring layers 3 is 20 μm, it is possible to prevent insulation failure due to migration. Even if the minimum distance between the wiring layers 3 is 10 μm, or even 5 μm, it is possible to prevent insulation failure due to migration.

  In the present embodiment, the minimum distance between the wiring layers 3 is not less than 5 μm and not more than 20 μm. Therefore, the thickness dimension of the wiring substrate 1 can be made as small as possible after preventing insulation failure due to migration. When the minimum distance between the wiring layers 3 is less than 5 μm, migration occurs and insulation failure due to migration occurs. When the minimum distance between the wiring layers 3 exceeds 20 μm, the effect of reducing the thickness dimension of the wiring board 1 as much as possible cannot be obtained.

FIG. 2 is a graph schematically showing the relationship between the maximum diameter of the void and the specific resistance. FIG. 2 shows a case where the void area occupation ratio in the cross section of the insulating layer 2 is 2.5%. In FIG. 2, the horizontal axis represents the maximum diameter of voids present inside the insulating layer 2, and the vertical axis represents the specific resistance of the insulating layer 2. The specific resistance of the insulating layer 2 is 10 ¹¹ Ω · cm when the maximum diameter of the void is 4 μm. The specific resistance of the insulating layer 2 decreases as the maximum diameter of the void increases from 4 μm. The specific resistance of the insulating layer 2 increases as the maximum diameter of the void decreases from 4 μm. Thus, when the maximum diameter of the void is 4 μm or less, it is possible to achieve a specific resistance of 10 ¹¹ Ω · cm at which no insulation failure occurs.

FIG. 3 is a graph schematically showing the relationship between the void area occupation ratio and the specific resistance in the cross section. In FIG. 3, the case where the maximum diameter of the void which exists in the inside of the insulating layer 2 is 4 micrometers is shown. In FIG. 3, the horizontal axis represents the void area occupation ratio in the cross section of the insulating layer 2, and the vertical axis represents the specific resistance of the insulating layer 2. The specific resistance of the insulating layer 2 is 10 ¹¹ Ω · cm when the void area occupation ratio is 2.5%. The specific resistance of the insulating layer 2 decreases as the void area occupancy increases from 2.5%. The specific resistance of the insulating layer 2 increases as the void area occupancy decreases from 2.5%. Thus, when the void area occupation ratio is 2.5% or less, it is possible to achieve a specific resistance of 10 ¹¹ Ω · cm that does not cause insulation failure.

  FIG. 4 is a flowchart for explaining the manufacturing procedure of the wiring board 1. With reference to this FIG. 4, the manufacturing method of a glass ceramic sintered compact and the manufacturing method of the wiring board 1 are demonstrated. When the manufacturing operation of the wiring board 1 is started, first, glass powder and ceramic powder are prepared in step a1.

The glass powder contains at least SiO ₂ and contains at least one selected from Al ₂ O ₃ , B ₂ O ₃ , ZnO, alkaline earth metal oxides and alkali metal oxides. As the glass powder, borosilicate glass such as SiO ₂ —B ₂ O ₃ system and SiO ₂ —B ₂ O ₃ —Al ₂ O ₃ —MO system (M represents Ca, Sr, Mg, Ba or Zn). , Alkali silicate glass, Ba glass, Bi glass and the like. These glass powders, upon firing, have a crystalline phase of lithium silicate, quartz, cristobalite, cordierite, mullite, anorthite, serdian, diopside, spinel, garnite, willemite, dolomite and petalite and their substituted derivatives. One or more of them are deposited.

  The ratio A (= ρ2 / ρ1) of the density ρ2 of the crystal phase to the density ρ1 of the glass powder is 1.00 or more and 1.15 or less, preferably 1.00 or more and 1.05 or less.

Examples of the ceramic powder include at least one selected from Al ₂ O ₃ , ZrO ₂ , mullite, forsterite, enstatite, spinel, and magnesia. By using ceramic powder mixed with glass powder, the strength of the sintered body can be improved and the characteristics of the sintered body can be improved. The particle size of the ceramic powder is about the same as the particle size of the glass powder.

  The ratio of the glass powder to the total amount of the glass powder and the ceramic powder is preferably 45% by mass to 80% by mass, and more preferably 50% by mass to 70% by mass. Since the glass powder ratio is not too short, voids in the sintered body can be reduced. When the proportion of the glass powder is not excessive, the strength of the sintered body is increased.

  The average particle diameter D50 of each of the glass powder and the ceramic powder is 1.0 μm or more and 2.0 μm or less, preferably 1.2 μm or more and 1.8 μm or less, more preferably 1.4 μm or more and 1.6 μm or less. is there.

The particle size distribution of each of the glass powder and the ceramic powder is such that the particle size of 10% cumulative from the fine particle side of the number cumulative distribution is D10, and the particle size of 50% cumulative from the fine particle side of the number cumulative distribution is D50. When the 90% cumulative particle size from the fine particle side is D90, the following formula (1) is satisfied, preferably the following formula (2) is satisfied, and more preferably the following formula (3) is satisfied.
0.7 ≦ (D90−D10) / D50 ≦ 2 (1)
0.7 ≦ (D90−D10) /D50≦1.6 (2)
0.7 ≦ (D90−D10) /D50≦1.0 (3)

  Next, in step a2, an organic binder or the like is added to the glass powder and the ceramic powder to generate a molding slurry. More specifically, 5 to 20 parts by mass of an acrylic resin as an organic binder and 2 to 8 parts by mass of DBP (dibutyl phthalate) as a plasticizer are added to 100 parts by mass of the glass ceramic composition, and toluene or isopropyl as a solvent. It is prepared by adding 25 to 55 parts by mass of alcohol to produce a molding slurry. Thereafter, the molding slurry is formed into a sheet shape by a doctor blade method, a rolling method, a press method, or the like, thereby producing a green sheet that is a molded body having a thickness dimension of about 20 μm to 50 μm. The green sheet becomes a precursor of the insulating layer 2.

  Next, in step a3, a wiring portion precursor including the via-hole conductor 4 and the wiring layer 3 is formed on the green sheet. First, the precursor of the via-hole conductor 4 is formed on a green sheet, and then the precursor of the wiring layer 3 is formed on the green sheet.

  In forming the precursor of the via-hole conductor 4 on the green sheet, first, a via-hole having a diameter of 80 to 200 μm is formed on the green sheet by laser, micro drilling, punching, or the like. Next, the via hole is filled with the via hole conductor paste. The filling layer formed by filling the via hole with the via hole conductor paste serves as a precursor of the via hole conductor 4.

  The via hole conductor paste contains a metal component as a main component. The via-hole conductor paste contains at least one selected from W, Mo, Mo, Cu, and Ag as a metal component. Considering that the via hole conductor paste is fired at a low temperature together with the green sheet, the metal component of the via hole conductor paste is preferably Cu or Ag. By including Cu or Ag as the metal component, the resistance of the via-hole conductor 4 can be reduced.

  In the via hole conductor paste, in addition to the metal component, an organic binder made of an acrylic resin and an organic solvent such as terpineol and dibutyl phthalate are homogeneously mixed. The organic binder is mixed at 0.5 to 15.0 parts by mass with respect to 100 parts by mass of the metal component, and the organic solvent is mixed at 5 to 100 parts by mass with respect to 100 parts by mass of the solid component and the organic binder. It is preferable. The via-hole conductor paste may contain less than 20 parts by mass of a ceramic filler, a glass component, or the like with respect to 100 parts by mass of the via-hole conductor paste.

  In forming the precursor of the wiring layer 3 on the green sheet, a pattern conductor paste is applied to the surface of the green sheet by a screen printing method. The coating layer formed by coating the pattern conductive paste on the surface of the green sheet serves as a precursor of the wiring layer 3. Since the pattern conductor paste is similar to the above-described via hole conductor paste, description of the pattern conductor paste is omitted. Hereinafter, the via hole conductor paste and the pattern conductor paste may be simply referred to as a conductor paste.

  Next, in step a4, a plurality of green sheets are laminated and pressure-bonded to form a green sheet laminate. When forming a laminate of green sheets, heat and pressure are applied to the laminated green sheets, and an adhesive containing an organic binder, plasticizer and solvent is applied between the green sheets and heated. A method of crimping can be employed.

  Next, in step a5, the laminate is heat-treated in a nitrogen atmosphere at 400 ° C. to 750 ° C. to decompose and remove organic components and the like in the green sheet and the conductor paste, and then a nitrogen atmosphere at 750 ° C. to 1050 ° C. Bake in. In this firing, the glass is softened during the temperature rise in the sintering process to generate a liquid phase, the solid phase particles are rearranged, and volume shrinkage occurs in the laminate, whereby sintering proceeds. Subsequently, when the firing temperature is further increased, a part of the glass is crystallized. As described above, sintering is completed when the laminate is densified by volume shrinkage and a necessary crystal phase is precipitated.

  The temperature range in which volume shrinkage occurs in the laminate and the temperature range in which the crystal phase precipitates may be completely separated or may partially overlap. In either case, the volumetric shrinkage of the laminate ends when the rearrangement of the solid phase particles is completed, and the volumetric shrinkage of the laminate hardly occurs even when the firing temperature rises further. When the crystal phase is precipitated from the glass after the volume shrinkage, if there is a difference between the density of the glass and the density of the crystal phase, the crystal phase is generally higher in density than the glass. As a result, the volume is reduced and voids are generated. When the crystalline phase is formed, the rearrangement of the solid phase particles has already been completed, and the volume shrinkage of the laminate is unlikely to occur, so this void is not lost by sintering, but remains void after the end of firing. .

  If the cooling rate of firing is too fast, cracks due to the difference in thermal expansion between the green sheet and the conductor paste occur, and therefore the cooling rate is preferably 400 ° C./hr or less. During firing, a load may be applied by placing a weight on the upper surface of the laminate. The load is selected from 50 Pa to 1 MPa. By applying a load in this way, it is possible to prevent the laminate from warping and to reduce voids. Further, by firing at as low a temperature as possible, the wiring substrate 1 having the insulating layer 2 made of a sintered glass ceramic having a fine structure can be obtained. When the wiring board 1 is obtained in this way, the manufacturing operation of the wiring board 1 is finished.

  The crystallinity of the insulating layer 2 is preferably 60% by mass or more and 99.5% by mass or less, and more preferably 90% by mass or more and 99.5% by mass or less. The high degree of crystallinity means that there is a crystalline phase in addition to the ceramic powder that was in the crystalline phase before firing, and the crystalline phase is precipitated from the glass by firing. And the voids are not lost. As a result, the voids in the insulating layer 2 increase. The higher the crystallinity, the greater the effect that the ratio A is 1.00 or more and 1.15 or less. Since the degree of crystallinity is 99.5% by mass or less, the degree of freedom in designing the glass material is increased, and thus the ratio A can be made close to 1.

  According to this embodiment, since the value of the ratio A (= ρ2 / ρ1) of the density ρ2 of the crystal phase to the density ρ1 of the glass powder is 1.00 or more and 1.15 or less, The difference between the volume occupied by the glass powder and the volume occupied by the crystal phase in the sintered body is reduced, and voids generated inside the insulating layer 2 due to this difference, specifically, a fine particle having a maximum diameter of less than 5 μm. Voids can be significantly reduced. As a result, the maximum diameter of voids present in the insulating layer 2 is controlled to 2 μm or more and 4 μm or less, and the void area occupation ratio in the cross section of the insulating layer 2 is controlled to 1.0% or more and 2.5% or less. Can do. Therefore, even if the thickness dimension is about 20 μm, it is possible to realize the insulating layer 2 that prevents insulation failure due to migration. When the ratio A exceeds 1.15, the above-described effects cannot be obtained.

  Further, glass powder and ceramic powder having an average particle diameter D50 of 1.0 μm or more and 2.0 μm or less and having a particle size distribution satisfying the above formula (1) are used. Thereby, in the sintering process, the liquid phase of the glass powder easily penetrates into the gaps between the solid phase particles. Therefore, rearrangement of the solid phase particles easily occurs due to the flow of the liquid phase, and the packing of the solid phase particles becomes dense and densified. As a result, generation of voids corresponding to voids between the solid phase particles can be suppressed.

  It is difficult to prepare glass powder and ceramic powder having an average particle diameter D50 of less than 1.0 μm, and the use of such glass powder and ceramic powder increases the manufacturing cost. In addition, the fine glass powder and ceramic powder are aggregated, resulting in an increase in voids. When at least one of glass powder and ceramic powder has an average particle diameter D50 of more than 2.0 μm, the above-described effects cannot be obtained. It is difficult to prepare a glass powder and a ceramic powder having (D90-D10) / D50 of less than 0.7, and the use of such a glass powder and a ceramic powder increases the manufacturing cost. When (D90-D10) / D50 exceeds 2 for at least one of glass powder and ceramic powder, the above-described effects cannot be obtained.

  In the above-described embodiment, the glass ceramic sintered body is used as the insulating layer 2 of the wiring board 1 which is a high-density multilayer wiring board. However, the glass ceramic sintered body is used in an IC (Integrated Circuit) or transistor package. It may be used, or may be used for an electronic component for electrical insulation.

  First, a glass powder having the glass composition shown in Table 1 and having an average particle size, particle size distribution and density shown in Table 2, and an alumina powder having an average particle size and particle size distribution shown in Table 2 as a ceramic powder And prepared.

The glass powder includes diopside crystals (density 3.170 g / cm ³ ), serdian crystals (density 3.290 g / cm ³ ), anorthite crystals (density 2.702 g / cm ³ ), cordierite crystals (density 2 .547 g / cm ³ ) were prepared so that the composition and density were adjusted.

The density of the glass powder is measured by the pycnometer method described in Japanese Industrial Standard (JIS) R1620 [Method for Measuring Fine Particle Density of Fine Ceramics Powder]. Specifically, glass powder (sample) was first dried in an air bath at 200 ° C. for 1 hour and cooled to room temperature in a desiccator. 4 g of this sample was collected in a specific gravity bottle, completely immersed in a small amount of 1-butanol, degassed under reduced pressure until no bubble generation was observed under a vacuum of 13.33 kPa or less, and then placed in a specific gravity bottle. -Fill butanol to a predetermined liquid volume and measure the mass at that time. The density of the glass powder was calculated by the following formula (4).
ρ = ρ _L × (m _P2 −m _{P 1} ) / [(m _P4 −m _P1 ) − (m _P3 −m _P2 )] (4)

In the above formula (4), ρ _L represents the specific gravity of the immersion liquid (1-butanol) at the measurement temperature, m _P1 represents the mass of the measurement container (specific gravity bottle), and m _P2 represents the sample placed in the measurement container. _{M p3} represents the mass when the sample and the prescribed amount of immersion liquid were added to the measurement container, and m _P4 represents the mass when the prescribed amount of immersion liquid was added to the measurement container.

For the measurement, an apparatus in which a vacuum pump “G-100D” manufactured by ULVAC, Inc. was connected to “Auto True Denser MAT5000” manufactured by Seishin Co., Ltd. was used. The measurement was performed at room temperature (20 to 30 ° C.). The specific gravity of 1-butanol is given in the literature (Gulf Publishing
From the company “Physical Properties of Hydrocarbons” Volume 1 page 67, Fig. 8-6D), the specific gravity at 20 ° C is 0.8096, the specific gravity at 30 ° C is 0.8021, and these values are linearly interpolated. The calculated value was used.

  Next, according to the composition shown in Table 2, glass powder and alumina powder were mixed to produce a glass ceramic composition. To 100 parts by mass of each glass ceramic composition, 10 parts by mass of an acrylic resin as an organic binder, 5 parts by mass of DBP (dibutyl phthalate) as a plasticizer, and 35 parts by mass of toluene as a solvent are added, and 36 hours by a ball mill. Mixing was performed to prepare a slurry for molding. A green sheet having a thickness of about 20 μm to 50 μm was prepared by a doctor blade method using a molding slurry.

  Next, 1 part by mass of alumina powder and 10 parts by mass of glass powder are weighed with respect to 100 parts by mass of Cu powder, and acrylic resin as an organic binder and α-terpinol as an organic solvent are added to and kneaded, and used for via holes. A conductor paste was prepared. The organic binder is 2.0 parts by mass with respect to 100 parts by mass of the Cu powder, and the organic solvent is 40 parts by mass with respect to 100 parts by mass of the solid component and the organic binder. Such via hole conductor paste was filled into via holes formed at predetermined locations on the green sheet.

  Next, with respect to 100 parts by mass of Cu powder, 1 part by mass of alumina powder and 5 parts by mass of glass powder are weighed, and acrylic resin as an organic binder and α-terpinol as an organic solvent are added and kneaded to form a pattern. A conductor paste was prepared. The organic binder is 3.0 parts by mass with respect to 100 parts by mass of the Cu powder, and the organic solvent is 50 parts by mass with respect to 100 parts by mass of the solid component and the organic binder. Such a pattern conductive paste was applied to the surface of the green sheet by a screen printing method. The thickness dimension of the coating layer was about 10 μm to 30 μm.

  Next, green sheets were laminated and thermocompression bonded under conditions of 50 ° C. and 5 MPa to produce a laminate.

Next, the laminate is placed on an Al ₂ O ₃ setter, and is fired at 750 ° C. in a nitrogen atmosphere to decompose and remove organic components such as an organic binder. The wiring board was produced by baking for a time.

Thus, each wiring board used as samples 1-26 was produced.
About the insulating layer of the obtained wiring board, the precipitated crystal phase was identified by X-ray diffraction measurement. The results are shown in Table 2. In samples 1 to 4, diopside and alumina crystals were observed. In samples 5 to 8, crystals of serdian and alumina were observed. In Samples 9 to 12, anorthite and alumina crystals were observed. In Samples 13 to 26, cordierite and alumina crystals were observed. In all samples, the amount of alumina crystals was the same as the amount of alumina powder added as a raw material.

  Further, the crystallinity of the insulating layer of the obtained wiring board was measured. The results are shown in Table 2. The crystallinity is the ratio of crystals in the insulating layer of the wiring board. The degree of crystallinity is determined by analyzing the result of X-ray diffraction (XRD) measurement of the insulating layer by the Rietveld method, evaluating the type and amount (mass%) of crystals existing in the insulating layer, and detecting the amount of crystals It can be obtained by summing up (mass%). Regarding the Rietveld method, the “Crystal Analysis Handbook” Editorial Committee edited by the Crystallographic Society of Japan, “Crystal Analysis Handbook”, Kyoritsu Publishing Co., Ltd., September 1999, p. The method described in 492-499 was used.

Specifically, a RETAN-2000 program is applied to an X-ray diffraction pattern in a range of 2θ = 10 ° to 80 ° measured by the diffractometer method by adding a ZrO ₂ standard sample to the sample to be evaluated. the use, the correlation between the amount of the ZrO ₂ standard sample was added to the diffraction pattern by standard sample of ZrO _2, it was evaluated the type and the amount of crystals contained in a sample to be evaluated.

  Furthermore, the insulating layer of the obtained wiring board is mirror-polished, the cross section of the mirror-polished insulating layer is observed with a scanning electron microscope (abbreviated as SEM), and the photograph of the cross-section with the scanning electron microscope From the above, the maximum void diameter and void area occupancy were calculated using an image analyzer. The results are shown in Table 2.

  Specifically, the cross section was observed with a scanning electron microscope at a magnification of 500 times. Here, with respect to the cross section of the insulating layer having a thickness of 20 μm sandwiched between the wiring layers, an area of 20 μm in length (thickness) × 3 cm in width (width) was set as the evaluation region. For samples in which the dimension of the insulating layer sandwiched between the wiring layers was not 20 μm, the same area was evaluated by adjusting the width of the evaluation region. For example, for the sample 20, a vertical (thickness) 10 μm × horizontal (width) 6 cm region was used as the evaluation region.

  The cross section was observed with a scanning electron microscope at a magnification of 500 times, and the maximum diameter of all voids present in the evaluation region was calculated using an image analysis apparatus. In the present embodiment, the largest maximum diameter among the maximum diameters of the respective voids is defined as the maximum diameter of the void.

  The cross section is observed with a scanning electron microscope at a magnification of 500 times, and an image analysis apparatus is used to display a defective portion such as a void in a pixel whose density is higher than a predetermined threshold in an image corresponding to an evaluation area. The total number of pixels that are equal to or greater than the threshold value was determined to be the pixels that are being processed. Here, a defect portion such as a void is darker than the remaining smooth portion, and the fact that the density value is large is used. By calculating the ratio of the total number of pixels equal to or greater than the threshold to the total number of pixels in the entire image, the area occupancy ratio of defective portions such as voids in the evaluation region was obtained. This area occupancy is the void area occupancy in this example. In other words, the total area of defect portions such as voids existing in the cross section is calculated, the area occupancy rate of the defect portions in the cross section is obtained, and this area occupancy rate is defined as the void area occupancy rate.

  Furthermore, the specific resistance between the first surface wiring layer on one surface in the thickness direction of the obtained wiring board and the internal wiring layer formed between the insulating layers of the wiring board was measured. In measuring the specific resistance between the first surface wiring layer and the internal wiring layer, first, between the first surface wiring layer and the second wiring layer on the other surface in the thickness direction of the wiring board, 100V The voltage was applied for 20 seconds. Thereafter, the specific resistance between the first surface wiring layer and the internal wiring layer was measured using an insulation meter. The results are shown in Table 2.

From the results in Table 2, when the maximum diameter of the void is 4 μm or less and the void area occupancy is 2.5% or less, the insulating layer exhibits high insulation with a specific resistance of 10 ¹¹ Ω · cm or more. I understand.

In particular, it can be seen from the results of Sample 1 that a high specific resistance of 10 ¹³ Ω · cm is exhibited by extremely densifying the maximum void diameter to 2 μm and the void area occupation ratio to 1.5%.

From the results of Samples 20 and 21, it can be seen that even if the thickness dimension of the wiring layer is 5 μm and 10 μm, the specific resistance shows high insulation of 10 ¹¹ Ω · cm or more.

As in Samples 12, 16, 19, and 24, when the maximum void diameter is 5 μm or more and the void area occupancy is 2.6% or more, the specific resistance is 10 ¹⁰ Ω · cm or less. You can see that.

When the value of the ratio A (= ρ2 / ρ1) of the density ρ2 of the crystal phase to the density ρ1 of the glass powder exceeds 1.15 as in the samples 12 and 16, the specific resistance is low 10 ¹⁰ Ω · cm or less. It turns out to show sex.

If the average particle size of the glass powder is 2 μm or less as in Samples 17 and 18, the specific resistance is as high as 10 ¹¹ Ω · cm or more. As in Sample 19, the average particle size of the glass powder is It can be seen that when the thickness exceeds 2 μm, the specific resistance is as low as 10 ¹⁰ Ω · cm or less.

If (D90-D10) / D50 is 2 or less for the glass powder as in Samples 22 and 23, high resistivity with a specific resistance of 10 ¹¹ Ω · cm or more is exhibited. When (D90-D10) / D50 exceeds 2, it can be seen that the specific resistance is as low as 10 ¹⁰ Ω · cm or less.

It is sectional drawing which shows the structure of the wiring board 1 which is one Embodiment of this invention. It is a graph which shows roughly the relation between the maximum diameter of a void and specific resistance. It is a graph which shows roughly the relation between the void area occupation rate and specific resistance in a section. 4 is a flowchart for explaining a manufacturing procedure of the wiring board 1;

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Wiring board 2 Insulation layer 3 Wiring layer 4 Via-hole conductor 5 Electrical element

Claims (7)

A sintered ceramic body obtained by firing a compact containing glass powder and ceramic powder and precipitating at least one crystal phase from the glass powder during firing,
A glass-ceramic sintered body characterized in that the maximum diameter of voids present therein is 2 μm or more and 4 μm or less, and the void area occupancy in the cross section is 1.0% or more and 2.5% or less.   An insulating layer made of the glass-ceramic sintered body according to claim 1 and a wiring layer are alternately laminated to constitute a wiring board.   The wiring board according to claim 2, wherein a minimum distance between the wiring layers is 5 μm or more and 20 μm or less. A method for producing a sintered glass ceramic body, comprising firing a molded body containing glass powder and ceramic powder, and precipitating at least one crystal phase from the glass powder during firing,
A method for producing a sintered glass ceramic, wherein the ratio A (= ρ2 / ρ1) of the density ρ2 of the crystal phase to the density ρ1 of the glass powder is 1.00 or more and 1.15 or less.   The method for producing a glass ceramic sintered body according to claim 4, wherein an average particle diameter D50 of each of the glass powder and the ceramic powder is 1 µm or more and 2 µm or less. The particle size distribution of the glass powder and the ceramic powder is such that the particle size of 10% cumulative from the fine particle side of the number cumulative distribution is D10, and the particle size of 50% cumulative from the fine particle side of the number cumulative distribution is D50. When the particle size of 90% cumulative from the fine particle side is D90,
0.7 ≦ (D90−D10) / D50 ≦ 2
The method for producing a sintered glass ceramic body according to claim 4 or 5, wherein: A method of manufacturing a wiring board configured by alternately laminating insulating layers and wiring layers,
The said insulating layer is formed using the manufacturing method of the glass ceramic sintered compact as described in any one of Claims 4-6, The manufacturing method of the wiring board characterized by the above-mentioned.

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