JP5201903B2 - Multilayer wiring board, method for producing the same, and composition for via-hole conductor - Google Patents

Description

  The present invention relates to a multilayer wiring board in which firing shrinkage in a plane direction is suppressed by alternately laminating and firing two types of insulating ceramic green sheets having different shrinkage curves (behavior) in firing, a method for manufacturing the same, and It is related with the composition for via-hole conductors used for this.

  In recent years, there has been a demand for high-frequency circuit compatibility, high density, and high speed in wiring boards, and a dielectric constant lower than that of conventionally used alumina-based ceramic materials and a low wiring layer can be obtained. A low-temperature fired wiring board that can be made more resistive has attracted more attention.

  This low-temperature fired wiring board is used as a wiring board such as a semiconductor element housing package for housing a semiconductor element, a cellular phone, a personal handyphone system, a multilayer wiring board for high frequency used for various satellite communications, etc. Application to the field is underway.

  The low-temperature fired wiring board is obtained by applying a metallized wiring layer mainly composed of a low-resistance metal such as Cu, Ag, or Au formed by firing together with an insulating board to an insulating board made of glass ceramics. In terms of cost, a silver-based or copper-based material is used as the metallized wiring layer rather than a gold-based material.

  As a method for producing this low-temperature fired wiring board, a glass ceramic raw material powder, a slurry prepared by adding a solvent to an organic binder is formed into a sheet shape by a doctor blade method or the like, and through holes are punched into the obtained green sheet Then, a via hole conductor is formed by filling the through hole with a via hole conductor paste mainly containing Cu or Ag, and at the same time, the conductor paste mainly containing Cu or Ag is formed on the green sheet in a desired wiring pattern. A method of printing and forming by a screen printing method, etc., pressing and laminating a plurality of green sheets on which wiring patterns and via-hole conductors are formed, and firing at 800 to 1000 ° C. can be mentioned.

  On the other hand, with the recent high integration of semiconductor chips, the pitch of bumps has been narrowed, and it has been unavoidable to improve the dimensional accuracy of such a low-temperature fired wiring board. Therefore, in order to reduce the dimensional variation at the time of firing shrinkage, a manufacturing method has been proposed in which two types of glass ceramic green sheets having different firing shrinkage start temperatures are alternately laminated to suppress shrinkage in the plane direction (for example, patents). See reference 1.)

  In the method described in Patent Document 1, the shrinkage in the planar direction of the glass ceramic insulating layer (glass ceramic green sheet) is suppressed by the interaction of the two types of glass ceramic green sheets, and the shrinkage in the stacking direction is increased. Become.

  On the other hand, the via-hole conductor (composition for via-hole conductor) has a larger shrinkage in the plane direction and smaller shrinkage in the stacking direction than the glass ceramic insulating layer (glass ceramic green sheet). There arises a problem that separation occurs at the boundary with the ceramic insulating layer, and the via-hole conductor protrudes greatly from the surface of the insulating substrate.

Here, for the purpose of preventing cracks (separation) at the boundary between the via-hole conductor and the glass ceramic insulating layer and protrusion of the via-hole conductor from the substrate surface, the composition of the via-hole conductor is adjusted, specifically, Cu It has been proposed to add an inorganic boron compound (in the examples, H ₃ BO ₃ ) as an inorganic pore forming agent to a composition for a via-hole conductor containing as a main component (see Patent Document 2). The present invention seeks to achieve the above object by forming stress in the via-hole conductor to relieve stress during firing shrinkage.
Japanese Patent Laid-Open No. 2004-200679 JP 2002-176236 A

However, when H ₃ BO ₃ is added to the via-hole conductor composition, B ₂ O ₃ is formed after H ₂ O is released in the firing step, and the melting point of B ₂ O ₃ is about 450 ° C. And the glass softening temperature of glass in the glass ceramic green sheet (for example, 600 to 700 ° C.) is considerably lower, so that a large amount of boron contained in the via-hole conductor composition during firing as B ₂ O ₃ In other words, the glass ceramic green sheet diffuses into the glass ceramic green sheet, and the crystallinity is lowered to a region that greatly exceeds the vicinity of the via-hole conductor, resulting in a decrease in strength around the via-hole conductor 3. It was.

Further, in this low crystallinity region, the softening point of the glass is extremely lowered by the diffusion of B ₂ O ₃ at around 450 ° C., and the glass is softened at a temperature lower than the debinding temperature. The binder removal process does not proceed sufficiently, the binder remains as residual carbon in the glass, gas is generated due to the combustion of residual carbon during the main firing, and a large number of voids are formed in the vicinity of the via-hole conductor, resulting in a void ratio. As a result, there is a problem that the rate becomes higher than other regions, and as a result, the insulating property with other via-hole conductors close to each other is reduced.

  Furthermore, if the binder removal treatment is insufficient, the glass ceramic green sheet contains a large amount of residual carbon, so that the wettability between Ag or Cu, which is the main component of the via-hole conductor composition, and the glass ceramic green sheet. Decreases and the adhesive strength decreases. In particular, the manufacture of a multilayer wiring board in which two types of glass ceramic insulating layers sintered at different firing shrinkage start temperatures and firing shrinkage end temperatures as described in Patent Document 1 are alternately stacked to suppress planar shrinkage. When used in the method, there has been a problem in that the separation of the boundary between the via-hole conductor and the glass ceramic insulating layer and the protrusion of the via-hole conductor from the substrate surface cannot be suppressed.

  The present invention has been made in view of the above circumstances, has good dimensional accuracy, and provides separation at the boundary between the via-hole conductor and the glass-ceramic insulating layer without causing deterioration in strength or insulation around the via-hole conductor. An object of the present invention is to provide a multilayer wiring board that suppresses the generation and the via-hole conductor does not greatly protrude from the substrate surface, a manufacturing method thereof, and a composition for the via-hole conductor.

In the present invention, two types of glass ceramic insulating layers sintered at different firing shrinkage start temperatures and firing shrinkage end temperatures are alternately laminated, and at least the outermost glass ceramic insulation layer is mainly composed of Cu or Ag. In the multilayer wiring board on which the via-hole conductor is formed, the via-hole conductor has Cu or Ag as a main component, and a boron-containing crystal having a melting point of 722 to 1100 ° C. as a subcomponent with respect to 100 parts by mass of the main component. Formed by using a composition for via-hole conductor containing 0.1 to 10 parts by mass of a porous filler, and the glass ceramic insulating layer has a boron content in the vicinity of the via-hole conductor more than other areas A multilayer wiring characterized in that the degree of crystallinity and void ratio in the vicinity of the via-hole conductor is lower than in other areas It is a plate.

  Moreover, this invention contains 0.1-10 mass parts of boron containing crystalline filler which has a melting | fusing point in the range of 722-1100 degreeC as a subcomponent with Cu or Ag as a main component and 100 mass parts of this main component. Is a composition for via-hole conductors.

  Furthermore, the present invention provides a first step of producing a first glass ceramic green sheet and a second glass ceramic green sheet having a firing shrinkage start temperature and a firing shrinkage end temperature different from the first glass ceramic green sheet. A second step of forming a through hole in at least the first glass ceramic green sheet or the second glass ceramic green sheet disposed at the outermost position, and Cu or Ag as a main component in the through hole. A third step of filling a via-hole conductor composition containing 0.1 to 10 parts by mass of a boron-containing crystalline filler having a melting point of 722 to 1100 ° C. as a subcomponent with respect to 100 parts by mass of the main component; The first glass ceramic green sheet or the second glass filled with the composition for a via-hole conductor on the outermost side A fourth step of alternately laminating the first glass ceramic green sheet and the second glass ceramic green sheet so that the ceramic green sheet is disposed; And a fifth step of firing at a temperature of 1050 ° C.

  According to the composition for a via-hole conductor of the present invention, since it contains a boron-containing crystalline filler having a desired melting point, forming a via-hole conductor using this, the dimensional accuracy is good, and the strength around the via-hole conductor is reduced. The occurrence of separation at the boundary between the via-hole conductor and the glass-ceramic insulating layer is suppressed without causing a decrease in insulation, and it is possible to contribute to obtaining a multilayer wiring board in which the via-hole conductor does not protrude greatly from the substrate surface.

  And, according to the method for producing a multilayer wiring board of the present invention using this via-hole conductor composition, the boron component can be diffused from the via-hole conductor composition into the glass ceramic green sheet in a desired temperature range. The dimensional accuracy is good, the separation of the boundary between the via-hole conductor and the glass-ceramic insulating layer is suppressed, and the via-hole conductor protrudes greatly from the substrate surface without causing a decrease in strength or insulation around the via-hole conductor. A multilayer wiring board that does not occur can be obtained.

  In addition, the multilayer wiring board of the present invention has good dimensional accuracy, no large protrusion of the via hole conductor from the substrate surface, and further reduced strength and insulation around the via hole conductor, and the via hole conductor and the glass ceramic insulating layer. The occurrence of separation at the boundary is hardly observed.

  Hereinafter, an embodiment of a wiring board of the present invention will be described with reference to the drawings.

  In the multilayer wiring board of the present invention, two types of glass ceramic insulating layers sintered at different firing shrinkage start temperatures and firing shrinkage end temperatures are alternately laminated, and Cu or Ag is applied to at least the outermost glass ceramic insulation layer. A via-hole conductor as a main component is formed. Specifically, as shown in FIG. 1, first glass ceramic insulating layers 1a to 1e and second glass ceramic insulating layers 2a to 2d are alternately stacked. A surface wiring layer 4 is formed on the surface of the multilayer wiring board, and an internal wiring layer 5 is formed inside the multilayer wiring board. Furthermore, a via hole conductor 3 having a diameter of about 80 to 200 μm is formed so as to penetrate the thickness direction of the first glass ceramic insulating layers 1a to 1e and the second glass ceramic insulating layers 2a to 2d. The wiring layer 4 or the internal wiring layer 5 is electrically connected.

  The first glass ceramic insulating layers 1a to 1e and the second glass ceramic insulating layers 2a to 2d are made of different glass ceramics and are formed of glass alone or a composite material of glass and ceramic filler.

Specific examples of the glass include those that precipitate crystals of cordierite, enstatite, forsterite, mullite, anorthite, serdian, spinel, garnite, willemite, dolomite, lithium silicate, and substituted derivatives thereof after firing. As constituent components of this glass, in addition to SiO ₂ , alkali metal oxides such as Li ₂ O, K ₂ O and Na ₂ O, alkaline earth metal oxides such as CaO, MgO, BaO and SrO, Al ₂ O ₃ Examples thereof include borosilicate glass containing P ₂ O ₅ , ZnO, B ₂ O ₃ , and PbO.

  In addition, by adding a ceramic filler to glass to make a composite material, the strength can be improved and the firing temperature can be controlled. As ceramic fillers used in this composite material, quartz, cristobalite, corundum ( α-alumina), mullite, cordierite, forsterite and the like. In addition, it is appropriate that the mixing ratio of glass and ceramic filler is 30 to 70% by volume for glass and 70 to 30% by volume for ceramic filler.

The glass ceramic green sheet that becomes the first glass ceramic insulating layers 1a to 1e after firing and the glass ceramic green sheet that becomes the second glass ceramic insulating layers 2a to 2d after firing have a firing shrinkage start temperature and a firing shrink end temperature. Although it is different, the method for making the glass softening points different by changing the glass composition of the respective glass ceramic green sheets is the simplest method. In addition, TiO ₂ and CeO ₂ are used as third additives for varying the amount ratio of glass and ceramic filler in each glass ceramic green sheet and for varying the firing shrinkage start temperature and firing shrinkage end temperature. And adding a nucleating agent such as SnO. If the firing shrinkage start temperature and the firing shrinkage end temperature are different, the shrinkage suppressing effect in the planar direction can be obtained. To obtain the maximum effect, the firing shrinkage end temperature of one glass ceramic green sheet is obtained. It is preferable that the other glass ceramic green sheet has a higher firing shrinkage start temperature.

  The arrangement of the first glass ceramic insulating layers 1a to 1e and the second glass ceramic insulating layers 2a to 2d may be reversed.

  The glass ceramic insulating layers 1a to 1e and 2a to 2d have a boron content in the vicinity region 31 of the via-hole conductor 3 higher than that in the other regions, and the crystallinity and void ratio of the vicinity region 31 in the via-hole conductor 3 are different. It is important that it is lower than the region. Here, the boron content in the vicinity region 31 of the via-hole conductor 3 is higher than that in the other regions in the vicinity region 31 of the via-hole conductor 3 when the individual glass ceramic insulating layers 1a to 1e and 2a to 2d are viewed. It means that the boron content is higher than in other regions. Further, the crystallinity and void ratio in the vicinity region 31 of the via-hole conductor 3 are lower than those in other regions. The via-hole conductor 3 when the individual glass ceramic insulating layers 1a to 1e and 2a to 2d are viewed. In other words, the crystallinity and void ratio of the vicinity region 31 are lower than those of other regions. Specifically, the crystallinity is preferably 2% or more, and the void ratio is 1% or more. Preferably it is low.

  The neighborhood region 31 means a region from the outer periphery of the via-hole conductor 3 to a distance of about 50 μm. The crystallinity refers to the volume ratio of crystals in the sintered body.

  The fact that the vicinity region 31 of the via-hole conductor 3 has a higher boron content than the other regions is due to the diffusion of boron components from the conductor material forming the via-hole conductor 3 described later in the firing process of the multilayer wiring board. . Also, the vicinity region 31 of the via-hole conductor 3 has a lower crystallinity and void ratio than other regions because it diffuses from the conductor material forming the via-hole conductor 3 described later in the firing process of the multilayer wiring board. This is because the boron component hinders crystallization of the glass contained in the glass ceramic green sheet that becomes the glass ceramic insulating layer after firing.

  The glass contained in the glass ceramic green sheet is designed to precipitate crystals after firing, but by including a boron-containing crystalline filler in the conductor material (composition for via-hole conductor) forming the via-hole conductor 3. During firing, the boron component diffuses from the via-hole conductor 3 into the glass ceramic green sheet, preventing crystallization of the glass. This is because, since the boron component is a glass-forming product, in a system containing a large amount of boron component, the glass phase is stabilized and the system is changed to a system in which crystals are not precipitated.

  However, the boron-containing crystalline filler contained in the conductor material forming the via-hole conductor 3 is not limited to any material.

For example, when H ₃ BO ₃ is used as the boron-containing crystalline filler, the strength around the via-hole conductor and the insulation are reduced, and separation is generated at the boundary between the via-hole conductor and the glass ceramic insulating layer. Further, the via-hole conductor protrudes greatly from the substrate surface. These problems cannot be solved even when the amount of H ₃ BO ₃ added or the glass component in the glass ceramic green sheet is adjusted to suppress the reaction with the glass component in the glass ceramic green sheet as much as possible.

In the case of using a non-oxide compound, such as BN and B _{4 C} as a boron-containing crystalline filler, since the remains of the BN and B _{4 C} in the composition for hole conductor during firing, it obtained the desired effect As a result, separation occurs at the boundary between the via-hole conductor and the glass ceramic insulating layer, and the via-hole conductor protrudes from the substrate surface. Note that BN has a melting point of 3000 ° C. or higher, and B ₄ C has a melting point of 2350 ° C., which is not preferable. However, non-oxide compounds are also wettability with glass in the glass ceramic green sheet. Is not preferable.

In addition, when so-called borosilicate glass such as SiO ₂ —B ₂ O ₃ —Al ₂ O ₃ is used, the binder in the glass ceramic green sheet is scattered when the conductor material contains an amount for obtaining a desired effect. The boron component diffuses at a temperature of 400 to 700 ° C., which is the combustion temperature, and the binder removal process is not properly performed, and the generation of voids accompanying this becomes remarkable. That is, if it is attempted to suppress diffusion within this temperature range, the amount of borosilicate glass must be reduced, and the effect due to diffusion of the boron component cannot be exhibited, leading to the protrusion and separation of the via-hole conductor.

  On the other hand, as a via-hole conductor composition, 0.1 to 10 parts by mass of a boron-containing crystalline filler having a melting point of 722 to 1100 ° C. as a subcomponent with respect to 100 parts by mass of the main component (Cu or Ag). By including, the above problems can be solved.

For example, when colemanite or urexite is used as the boron-containing crystalline filler having a melting point in the range of 722 to 1100 ° C., H ₂ O is released in the firing step, but the melting point of the compound formed thereafter is 800 to 1000 ° C. (Because it is a natural raw material, the components are not constant, and the melting point varies depending on the composition ratio of the compound, but the melting point is much higher than 450 ° C. of B ₂ O ₃ alone). Then, the boron component does not diffuse into the glass ceramic green sheet and does not react with the glass. Therefore, since the binder removal process can be sufficiently performed in the temperature range of 400 to 700 ° C., there is no coarsening of voids due to residual carbon combustion at the time of the main firing, and so-called de-buy failure as in the case of using H ₃ BO _3. Thus, the occurrence of problems as in the case of using borosilicate glass can be suppressed. Also, since colemanite and urexite are oxides, they have good wettability with the filler component in the glass ceramic green sheet, reducing the wettability between the via-hole conductor composition and the glass ceramic green sheet, thereby reducing the adhesive strength. There is no end to it. When the melting point exceeds 1400 ° C., the boron component does not diffuse from the via-hole conductor, and the desired effect cannot be obtained.

  And it is important to contain 0.1-10 mass parts of boron containing crystalline fillers as a subcomponent with respect to 100 mass parts of main components (Cu or Ag). When the content of the boron-containing crystalline filler is less than 0.1 parts by mass, it is difficult to make the degree of crystallinity in the region near the via-hole conductor 3 lower than in other regions. On the other hand, when the content of the boron-containing crystalline filler exceeds 10 parts by mass, a large amount of boron component diffuses, and the region with low crystallinity becomes more extensive than the neighboring region, with a decrease in strength, The adhesive strength between the via-hole conductor and the glass ceramic insulating layer is lowered, and it becomes difficult to suppress the occurrence of separation and the protrusion of the via-hole conductor.

  On the other hand, when the content of the boron-containing crystalline filler as a subsidiary component is 0.1 to 10 parts by mass with respect to 100 parts by mass of the main component (Cu or Ag), only Young in the vicinity of the via-hole conductor 3 is used. The rate is reduced and the stress generated by the difference in firing shrinkage behavior between the via-hole conductor and the glass ceramic insulating layer can be relieved to prevent separation, and the via-hole conductor 3 and the glass ceramic insulating layer can be prevented. Since the adhesiveness is improved, the shrinkage of the via-hole conductor 3 in the planar direction is suppressed and the shrinkage in the thickness direction is promoted, so that the protrusion of the via-hole conductor can also be prevented.

  From the above, by including 0.1 to 10 parts by mass of boron-containing crystalline filler having a melting point in the range of 722 to 1100 ° C., the degree of crystallinity in the vicinity of the via-hole conductor 3 is made lower than in other areas. At the same time, the void ratio can be made lower than in other regions.

  The via-hole conductor composition for forming the via-hole conductor 3 may contain various glasses and ceramic fillers for the purpose of matching the firing shrinkage behavior with the glass-ceramic green sheet for forming the glass-ceramic insulating layer.

  Next, the manufacturing method of the multilayer wiring board of this invention is demonstrated.

  The method for producing a multilayer wiring board according to the present invention includes a first glass ceramic green sheet and a second glass ceramic green sheet having a firing shrinkage start temperature and a firing shrinkage end temperature different from the first glass ceramic green sheet. A first step of producing, a second step of forming a through hole in at least the first glass ceramic green sheet or the second glass ceramic green sheet disposed at the outermost portion, and Cu in the through hole. Alternatively, a via-hole conductor composition containing 0.1 to 10 parts by mass of a boron-containing crystalline filler whose main component is Ag and whose melting point is 722 to 1100 ° C. as an auxiliary component with respect to 100 parts by mass of the main component is filled. And the third glass ceramic green sheet filled with the via hole conductor composition on the outermost side. A fourth step of producing a laminate by alternately laminating the first glass ceramic green sheets and the second glass ceramic green sheets so that the second glass ceramic green sheets are disposed; And a fifth step of firing the laminate at a temperature of 850 to 1050 ° C.

  First, a glass component as described above, or a glass component and a ceramic filler are mixed to prepare two types of glass ceramic compositions having different firing shrinkage start temperatures and firing shrinkage end temperatures, and an organic binder or the like is added to the mixture. After the addition, the first glass ceramic green sheet and the second glass ceramic green sheet are produced by forming into a sheet shape by a doctor blade method, a rolling method, a pressing method or the like.

  And two types of obtained glass ceramic green sheets are heat-pressed, and a composite glass ceramic green sheet is obtained. Through holes (through holes) are formed in the obtained composite glass ceramic green sheet by a method such as NC punch, laser, or mold. Thereafter, the through-hole (through-hole) is filled with a via-hole conductor paste (via-hole conductor composition) by screen printing.

  According to the present invention, in the via hole conductor paste, as described above, a boron-containing crystalline filler having a melting point in the range of 722 to 1100 ° C. is added to 100 parts by mass of the main component (Cu or Ag). It is characterized by containing 0.1 to 10 parts by mass as a component.

  The Cu or Ag component as the main component is desirably a spherical powder having an average particle size of 0.5 to 5 μm, preferably 3 to 5 μm. This is because the sintering behavior of the via-hole conductor paste is approximated to the sintering behavior of the glass ceramic green sheet, and the filling accuracy is improved. Further, in the via-hole conductor paste, in addition to the inorganic components, an organic binder made of an acrylic resin and an organic solvent such as α-terpineol, dibutyl phthalate, and butyl carbitol are formed by homogeneous mixing. The organic binder is desirably mixed in an amount of 1 to 10 parts by mass and the organic solvent component in an amount of 5 to 30 parts by mass with respect to 100 parts by mass of the inorganic component.

  Next, a conductor paste is printed on the surface of the obtained composite glass ceramic green sheet. The conductor paste to be used is the same Ag or Cu as the main component of the via-hole conductor paste, and it is desirable to use a spherical powder having an average particle size of 0.5 to 10 μm, preferably 3 to 5 μm. This is because the sintering behavior of the wiring pattern is approximated to the sintering behavior of the glass ceramic green sheet and the printing accuracy is improved.

  Then, the composite glass ceramic green sheet formed with the wiring pattern and filled with the via-hole conductor paste is laminated and pressure-bonded, and the first glass ceramic formed with the outermost through-hole and filled with the via-hole conductor paste A green sheet or the second glass ceramic green sheet is disposed to form a laminate in which the first glass ceramic green sheet and the second glass ceramic green sheet are alternately stacked.

  Thereafter, this laminate is heat-treated in air at 400 to 800 ° C. or in a nitrogen atmosphere containing water vapor to decompose and remove organic components in the glass ceramic green sheet or paste, and then in a nitrogen atmosphere at 850 to 1050 ° C. By simultaneous firing in a steam-containing nitrogen atmosphere, a multilayer wiring board having a metallized wiring layer and a via-hole conductor can be produced.

  In the production of the multilayer wiring board of the present invention, only the internal metallized wiring layer and the via-hole conductor are fired simultaneously with the insulating substrate, and the surface of the multilayered wiring board on which the surface metallized wiring layer has already been fired is mainly composed of Ag or Cu. A conductive paste as a component may be formed by baking. In that case, the baking treatment can be performed at a temperature of 600 to 1000 ° C. in a nitrogen atmosphere.

  Finally, the sintering behavior of two types of glass ceramic green sheets will be described.

  The firing shrinkage starting temperature of the first glass ceramic green sheet is preferably 600 to 750 ° C., and the firing shrinkage starting temperature of the second glass ceramic green sheet is preferably 700 to 800 ° C. Due to this temperature difference, firing shrinkage in the planar direction is suppressed. In addition, it is possible to mainly contract in the thickness direction. That is, the first glass ceramic green sheet has a firing shrinkage start temperature higher than the firing contraction start temperature of the second glass ceramic green sheet. The second glass ceramic green sheet is in an unfired stage, whereby the first glass ceramic green sheet is prevented from shrinking in the plane direction, and as a result, firing shrinkage is mainly performed in the thickness direction. On the other hand, in the temperature range in which the second glass ceramic green sheet is fired and shrunk, the first glass ceramic green sheet that has already been fired and shrunk prevents the second glass ceramic green sheet from shrinking in the plane direction, and as a result, mainly the thickness. Fire shrinkage in the direction.

  In the following manner, an evaluation board for evaluating the presence or absence of a gap between the via-hole conductor and the through-hole wall surface (the boundary between the via-hole conductor and the glass ceramic insulating layer) was produced. In this evaluation board, an insulating layer having a width of 30 mm × 30 mm and a thickness of 330 μm is laminated, and a total of 25 via-hole conductors having a diameter of 90 μm are arranged in the center of the board in 5 rows × 5 columns at intervals of 500 μm. Is a land having a diameter of 125 μm. A manufacturing method will be described below.

First, the 1st glass ceramic green sheet used as the 1st glass ceramic insulating layer was produced. SiO ₂ is 9% by mass, B ₂ O ₃ is 17% by mass, P ₂ O ₅ is 1.7% by mass, Al ₂ O ₃ is 17% by mass, MgO is 44% by mass, BaO is 8% by mass, SnO ₂ Of 1.7% by mass, CaO 0.5% by mass, and NaO 0.1% by mass of glass powder and quartz powder were prepared. These were 85.6% by mass of glass and 14.4% of quartz powder. %, And an organic binder was added to prepare a glass ceramic composition. Using the slurry prepared by adding acrylic resin as an organic binder, dioctyl phthalate as a plasticizer, and toluene as a solvent to the raw material powder, the first glass ceramic green sheet having a thickness of 200 mmSQ and a thickness of 10 μm is formed by a doctor blade method. Was made.

Then, the 2nd glass ceramic green sheet used as the 2nd glass ceramic insulating layer was produced. SiO ₂ is 35.9 mass%, B ₂ O ₃ is 12 mass%, Al ₂ O ₃ is 6.6 mass%, MgO is 17.5 mass%, CaO is 2.5 mass%, ZnO is 14.4 mass%. A glass powder containing 5% by mass, a quartz powder, and a CaZrO ₃ powder were prepared. These were weighed 58.7% by mass of glass, 36.5% by mass of quartz powder, and 4.8% by mass of CaZrO ₂ powder. A glass ceramic composition was prepared by adding a binder. Using the slurry prepared by adding acrylic resin as an organic binder, dioctyl phthalate as a plasticizer, and toluene as a solvent to the raw material powder, a second glass ceramic green sheet having a thickness of 200 mmSQ and a thickness of 125 μm is formed by a doctor blade method. Was made.

  Then, the first glass ceramic green sheet for the first glass ceramic insulating layer and the second glass ceramic green sheet for the second glass ceramic insulating layer are prepared one by one, and these are thermocompression-bonded to form a composite. A glass ceramic green sheet was prepared. Also, for the lowermost layer, two first glass ceramic green sheets for the first glass ceramic insulating layer and one second glass ceramic green sheet for the second glass ceramic insulating layer are prepared, The first glass ceramic green sheet was heat-pressed so as to sandwich the second glass ceramic green sheet.

  Here, the manufactured composite glass ceramic green sheet was provided with a through hole having a diameter of 90 μm by punching.

  Next, a via-hole conductor paste was prepared. Add subcomponents in 100 parts by weight of Ag or Cu powder at the ratio shown in Table 1, add acrylic resin as organic binder, and mixed solution of terpineol and dibutyl phthalate as solvent (80:20 by mass). And kneading to prepare a via-hole conductor paste. The prepared via-hole conductor paste was filled into the through-hole provided earlier by screen printing.

  Subsequently, a wiring conductor paste was produced. Ag or Cu powder and glass powder are prepared, an acrylic resin is added as an organic binder to these powders, a mixed solution of terpineol and dibutyl phthalate (80:20 by weight) as a solvent, kneaded, and a wiring conductor A paste was prepared. The obtained wiring conductor paste was printed by a screen printing method. A pattern having a diameter of 125 μm was printed as a land pattern directly on the via-hole conductor paste.

  A laminate was produced using the composite glass ceramic green sheet thus obtained. Prepare three composite glass ceramic green sheets and one composite glass ceramic green sheet prepared for the bottom layer, apply the adhesive uniformly between the glass ceramic green sheets, and pressurize under conditions of 45 ° C and 4 MPa Lamination was performed.

Subsequently, in order to place these laminated bodies on an Al ₂ O ₃ base plate and decompose and remove organic components such as an organic binder, when the conductor is Ag, de-buy at 400 ° C. in the air. Then, firing was performed under the conditions of 900 ° C. × 1 hour. When the conductor was Cu, heat treatment was performed at 700 ° C. in a nitrogen atmosphere, followed by firing in a nitrogen atmosphere at 900 ° C. for 1 hour.

  The obtained substrate was subjected to electroless Ni plating and Au plating to obtain an evaluation substrate.

The obtained evaluation substrate was immersed in a fluorescent penetrating flaw detection liquid, held in a desiccator for 2 hours in a vacuumed state until reaching a pressure of 1 × 10 ⁻² Pa, and then washed with tap water. The via-hole conductor was polished about 50 μm from the substrate surface in the substrate stacking direction, and the presence or absence of penetration of the fluorescent penetrating flaw detection liquid into the through hole was evaluated. In the evaluation, the substrate after polishing was observed with a fluorescence microscope, and a sample having through holes in which one or more fluorescent portions were recognized in 25 via holes was judged as NG, and in the case of 0 places, OK.

  Further, the difference in height between the via-hole conductor and the glass ceramic insulating layer surface was measured with a three-dimensional measuring instrument. The evaluation was OK within 15 μm.

In order to measure the degree of crystallinity, first, the substrate (glass ceramic insulating layer) at a distance of 1 mm or more from the via-hole conductor is pulverized, and chromium oxide (Cr ₂ O ₃ ) is mixed at a ratio of 1: 1 as a standard sample. Then, X-ray diffraction was performed, and the crystallinity was obtained by Rietveld analysis from the peak intensity of chromium oxide, which is a standard sample. The degree of crystallinity of the glass ceramic insulating layer (other regions) other than the neighboring region used in this example was approximately 75%. Then, in order to obtain the crystallinity in the vicinity of the via-hole conductor, the sample was filled with resin and polished so that the periphery of the via-hole conductor could be observed. Thereafter, the beam of the X-ray diffractometer was narrowed down, X-rays were irradiated at a position of about 25 μm from the outer periphery of the via-hole conductor, and the crystallinity was calculated from the peak intensity ratio.

  Furthermore, the cross section of the via-hole conductor was observed with a scanning electron microscope SEM (Scanning Electron Microscope) and an X-ray microanalyzer EPMA (Electron Probe Microanalyzer), and the thickness of the vicinity region around the via-hole conductor was measured. Moreover, the void ratio was calculated | required as follows from a SEM photograph. That is, from the SEM photograph, the void ratio was obtained by image analysis in a portion surrounded by a portion from the outer periphery of the via hole conductor to 50 μm and a portion surrounded by 100 μm and 150 μm from the via hole. The results are shown in Table 1.

Although not shown in the table, composition analysis was performed using a transmission electron microscope TEM (Transmission Scanning Electron Microscope), and it was confirmed that the boron content in the vicinity of the via-hole conductor was increased in the examples of the present invention. .

  Sample No. 3-5, 8-10, 14-23, 35-37, 40-42, 46-55, the boron component diffuses in the vicinity of the via-hole conductor, so that the degree of crystallinity in the vicinity of the via-hole conductor is different. And the void ratio is lower than other areas, and by relaxing the stress due to the firing shrinkage difference between the via-hole conductor and the glass ceramic insulating layer, the separation between the through-hole wall surface and the via-hole conductor is reduced. It was confirmed that it did not occur. Moreover, the via hole conductor protrusion height protruding from the substrate surface was 15 μm or less, which was a good result.

  However, sample no. In 1, 2, 7, 33, 34, and 39, there is no diffusion or small diffusion amount of boron component in the vicinity of the via-hole conductor, so stress due to the firing shrinkage difference between the via-hole conductor and the glass ceramic insulating layer can be relieved. As a result, separation occurred.

  Sample No. 6, 11, 38 and 43, since the boron component is excessively contained in the via-hole conductor composition, the boron component is excessively diffused in the glass ceramic green sheet, and the softening point of the glass is excessively lowered. As separation occurred.

Sample No. In 31, 32, 44 and 45, by using H ₃ BO ₃ as a boron component, the boron component diffused into the glass-ceramic green sheet at a low temperature of about 400 ° C., resulting in separation failure, resulting in separation. did.

  Sample No. In Nos. 12, 13, 46, and 47, the melting point of the boron-containing crystalline filler was low, and generation of voids and separation due to defective debonding were observed.

  Sample No. In 24-30 and 56-62, the melting point of the boron-containing crystalline filler was high, diffusion of the desired boron component did not occur, separation occurred, and the via-hole conductor protruded greatly.

It is a schematic sectional drawing of the multilayer wiring board of this invention.

Explanation of symbols

1a, 1b, 1c, 1d, 1e: first glass ceramic insulating layers 2a, 2b, 2c, 2d: second glass ceramic insulating layer 3: via-hole conductor 31: neighboring region 4: surface wiring layer 5: internal wiring layer

Claims (2)

Two types of glass ceramic insulating layers sintered at different firing shrinkage start temperatures and firing shrinkage end temperatures are alternately laminated, and at least the outermost glass ceramic insulation layer has a via-hole conductor mainly composed of Cu or Ag. In the formed multilayer wiring board,
The via-hole conductor contains Cu or Ag as a main component, and a via hole containing 0.1 to 10 parts by mass of a boron-containing crystalline filler having a melting point of 722 to 1100 ° C. as a subcomponent with respect to 100 parts by mass of the main component. It is formed using a conductor composition,
The glass ceramic insulating layer has a boron content in the vicinity of the via-hole conductor higher than that in other areas, and the crystallinity and void ratio in the vicinity of the via-hole conductor are lower than in other areas. A characteristic multilayer wiring board. A first step of producing a first glass ceramic green sheet and a second glass ceramic green sheet having a firing shrinkage start temperature and a firing shrinkage end temperature different from the first glass ceramic green sheet;
A second step of forming a through hole in at least the first glass ceramic green sheet or the second glass ceramic green sheet disposed at the outermost position;
A via hole containing Cu or Ag as a main component in the through hole and 0.1 to 10 parts by mass of a boron-containing crystalline filler having a melting point of 722 to 1100 ° C. as a subcomponent with respect to 100 parts by mass of the main component. A third step of filling the conductor composition;
The first glass ceramic green sheet and the second glass ceramic green sheet are disposed so that the first glass ceramic green sheet or the second glass ceramic green sheet filled with the via-hole conductor composition is disposed on the outermost side. A fourth step of alternately laminating glass ceramic green sheets to produce a laminate;
And a fifth step of firing the laminated body at a temperature of 850 to 1050 ° C.

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