JP4703208B2 - Multilayer wiring board and manufacturing method thereof - Google Patents

Description

  The present invention relates to a multilayer wiring board and a manufacturing method thereof, and more particularly to a multilayer wiring board having high density and strength, excellent moisture resistance, and suitable for a circuit board, and a manufacturing method thereof.

  Conventionally, dielectric ceramics have been widely used for dielectric resonators, dielectric substrates for MICs, waveguides, and the like in high frequency regions such as microwaves and millimeter waves. With the development and popularization of mobile communication and the like, the demand for dielectric ceramics as materials for electronic circuit boards and electronic components is increasing.

  As a dielectric porcelain composition for electronic circuit boards and electronic parts, glass that can be fired simultaneously with silver or copper, which are highly conductive metals, or a composite material of glass and ceramics, or a sintering aid Low-temperature fired ceramics that can be fired at 1000 ° C. or lower, which are made of ceramics containing them, have been developed.

  Such low-temperature fired ceramics are produced by producing a green sheet using a slurry containing a raw material powder containing glass and ceramic filler and a binder, and a desired wiring / circuit pattern electrode is screen printed on the inside and the surface thereof. Form by the method. Further, via hole conductors and through hole conductors for electrode connection are formed as necessary. Next, the green sheets having wiring / circuit pattern electrodes, via-hole conductors, and through-hole conductors are laminated in a desired layer configuration to form a laminated molded body. In this laminated molded body, the surface conductor is coated by a method such as coating using a dielectric or insulator paste, if desired, and then a ceramic electronic component comprising a multilayer wiring board is formed by simultaneous firing of low-temperature fired ceramics and electrodes. (For example, refer to Patent Documents 1 and 2).

In order to improve the dispersibility of the raw material powder, it has been proposed to add a phosphate ester to the slurry in such a low-temperature fired ceramic manufacturing process (see, for example, Patent Document 2).
JP-A-7-242440 Japanese Patent Laid-Open No. 2001-243837

However, in the method for manufacturing a multilayer wiring board described in Patent Document 2, although 2-7% by weight of phosphoric acid ester can improve the dispersibility in addition to slurry, a problem that sinterability that turn into poor is there were.

  Further, in Patent Document 2, since glass is softened and sintered during firing, ceramic powder particles are sintered while being rearranged. When a large amount of phosphorus is dissolved in glass, the glass is crystallized. Accelerated and softened fluidity is deteriorated, sufficient sintering density cannot be obtained, density variation becomes large, and as a result, a part with a high porosity is partially generated, and a fracture source is generated, so that the strength of the porcelain is increased. In addition to the decrease, there is a problem that moisture permeates and the insulation moisture resistance decreases due to migration of the electrode conductor.

  In addition, since a large amount of phosphorus is dissolved in the crystal, there is a problem that the Q value is deteriorated and fluctuates from a desired dielectric constant.

  Therefore, the present invention provides a multilayer wiring board having a high porcelain density, high strength and insulation moisture resistance, and a multilayer wiring board that can be easily manufactured even if a phosphate ester is added to the slurry to improve dispersibility. An object of the present invention is to provide a manufacturing method.

The method for producing a multilayer wiring board according to the present invention includes forming a plurality of green sheets formed by forming a slurry containing an inorganic powder and an organic component into a tape shape, and forming a via hole in a part of the green sheet. The via hole is filled with a conductor paste containing Cu and / or Ag to form a via conductor, and the conductor paste is printed and applied in a circuit pattern on the surface of the green sheet to form a wiring circuit layer. A circuit forming step, and a laminating step in which a plurality of green sheets including the green sheet produced in the forming step and / or the via conductor and the wiring circuit layer produced in the circuit forming step are laminated to produce a laminate. In the method for producing a glass ceramic wiring board comprising a firing step of firing the laminate, the slurry is 2a as an inorganic powder. A glass powder and containing Group 3a _elements, 0.02 in _{Al 2 O 3, CaTiO 3,} MgTiO 3, Mg 2 SiO 4, and at least one ceramic powder of MgO and SiO _2, P 2 _{O 5} in terms of And 0.30% by mass of a phosphorus-containing compound, and the porosity of the laminate after firing is 1 to 3% .

  In particular, it is preferable that the compound containing phosphorus is a phosphate ester, and after preparing a slurry containing the glass powder, the ceramic powder, and the organic component, the phosphate ester is added to the slurry.

  The glass powder preferably contains at least one element selected from Mg, Ca, Sr, and Ba and at least one element selected from B and Al.

  The glass powder is preferably crystallized glass powder.

  After the firing step, the crystallized glass preferably forms at least one of diopside, celsian, cordierite, anorthite, spinel, mullite, and forsterite.

  The multilayer wiring board of the present invention is produced by the above method, and is characterized in that a ceramic layer having a conductor layer on the surface and inside is laminated.

  The present invention can remarkably improve the wettability between glass and ceramic powder by using a specific amount of a compound containing phosphorus in a slurry containing a raw material powder in which a specific ceramic powder and a specific glass powder are combined. As a result, a multilayer wiring board with a high dielectric constant, low density variation, high strength and moisture resistance, high Q value, and desired dielectric constant can be realized. it can.

That is, the method for producing a multilayer wiring board according to the present invention comprises a forming step of forming a plurality of green sheets obtained by forming a slurry containing an inorganic powder and an organic component into a tape shape, and a part of the green sheet. A via circuit is formed by forming a via hole, filling the via hole with a conductor paste containing Cu and / or Ag to form a via conductor, and printing and applying the conductor paste in a circuit pattern on the surface of the green sheet. A laminate is produced by laminating a plurality of green sheets each including a circuit forming step for forming a green sheet and / or a green sheet produced in the forming step and / or a via conductor and a wiring circuit layer produced in the circuit forming step. In the method for producing a glass ceramic wiring board, comprising: a laminating step for firing; and a firing step for firing the laminate, A glass powder containing Group 2a and Group 3a element as a _{powder, Al 2 O 3, CaTiO 3} , and at least one ceramic powder of _{MgTiO 3, Mg 2 SiO 4,} MgO and SiO _2, in terms _of P 2 _{O 5} 0.02 to 0.30% by mass of a phosphorus-containing compound, and the porosity of the laminate after firing is 1 to 3% .

Thus, slurry, glass powder and the _Al 2 _O 3 containing Group 2a and Group 3a element as inorganic _{powder, CaTiO 3, MgTiO 3, Mg} 2 SiO 4, MgO, and at least one ceramic powder of SiO ₂ And a compound containing an organic binder and an organic solvent as organic components, and further containing 0.02 to 0.30% by mass or less in terms of P ₂ O ₅ with respect to 100 parts by mass of the inorganic powder. In addition, since the porosity after firing of the laminate is 1 to 3%, the wettability between the glass softened in the firing step and the ceramic powder is improved, so that the sintered density can be stably improved. it can. However, when phosphorus is included in the composition of glass or ceramics, improvement in wettability cannot be expected, and with the addition amount used in the present invention, the effect of improving the sintered density cannot be obtained. increasing the electrical properties and dielectric characteristics required for the multilayer wiring board is out of the desired properties, glass is devitrified, or becomes unsuitable as glass for low-temperature firing glass-ceramic, problems such results.

  In addition, since the multilayer wiring board of the present invention is manufactured by the above method, it is possible to realize a multilayer wiring board having high porcelain density, strength and insulation moisture resistance.

  The present invention is a method for producing a ceramic wiring board comprising a forming step for producing a green sheet, a circuit forming step for forming a wiring circuit layer, a laminating step for laminating the green sheet, and a firing step for firing the laminate. The present invention relates to a method of manufacturing a multilayer wiring board that can easily improve the sintered density. These steps will be described below.

(Molding process)
First, two kinds of glass powder and ceramic powder are prepared as raw inorganic powder. It is important that the glass powder contains Group 2a and Group 3a elements, and the ceramic powder contains at least one of Al ₂ O ₃ , CaTiO ₃ , MgTiO ₃ , Mg ₂ SiO ₄ , MgO, and SiO ₂ . By using such a combination, the effect of improving the wettability of the phosphorus-containing compound can be expected, and a porcelain with small density variation can be realized with high density, high Q value, high strength, and high insulation moisture resistance.

  The glass powder preferably contains at least one element selected from Mg, Ca, Sr, and Ba and at least one element selected from B and Al. Said element can further improve the wettability and sinterability of glass and ceramic powder in a baking process.

  Further, it is desirable that the glass powder is crystallized glass, and further, the crystallized glass forms at least one of diopside, celsian, cordierite, anorthite, spinel, mullite, and forsterite. desirable. This facilitates increasing the strength and reducing the dielectric loss.

Among these, as a combination of glass powder and ceramic powder, B ₂ O ₃ —SiO ₂ —Al ₂ O ₃ —MgO—BaO glass and CaTiO ₃ and / or MgTiO ₃ have high strength because of high density. For this reason, CaO-Al ₂ O ₃ —MgO—SiO ₂ glass and Al ₂ O ₃ are BaO—Al ₂ O ₃ —SiO ₂ —ZnO glass and Mg ₂ SiO ₄ and / or MgO because of high insulation moisture resistance. And / or SiO ₂ is preferably B ₂ O ₃ —SiO ₂ —Li ₂ O—BaO—CaO glass and CaTiO ₃ and / or MgTiO ₃ because of high Q value.

It is also important that the inorganic powder contains 0.02 to 0.30% by mass of a phosphorus-containing compound in terms of P ₂ O ₅ . By adding such a phosphorus-containing compound, the wettability between the glass softened in the firing process and the ceramic powder is improved, the rearrangement of the ceramic powder is promoted, and the sintered density can be stably improved. In particular, the addition of 0.04 to 0.20% by weight or less is desirable in that the porosity becomes 2% or less and the strength and moisture resistance are improved.

As the compound containing phosphorus, either a solid or a liquid can be used. For example, examples of the solid include P ₂ O ₅ , calcium phosphate, barium phosphate, and aluminum phosphate. Among these, P ₂ O ₅ is particularly preferable because it exhibits a wettability effect from a low temperature in the firing process.

Moreover, since it disperse | distributes uniformly, it is preferable to use a liquid rather than solid as a phosphorus containing compound. Examples of the liquid and / or solution include phosphate ester, dibutyl phosphate, dimethyl phosphate, ammonium phosphate, and P ₂ O ₅ . The solvent is preferably toluene, various alcohols, particularly isopropyl alcohol. Among these, in particular, the use of a phosphate ester is desirable because phosphorus can be supplied more selectively and more uniformly on the surface of the glass and ceramic powder, so that the sintered density can be further stabilized and improved.

  In the case of a solid, it may be added at the same time as the inorganic powder. In particular, it is preferable to add an inorganic powder, an organic binder, an organic solvent, and, if desired, a plasticizer to form a slurry, and add a liquid phosphorus-containing compound after mixing. Thereby, wettability can be remarkably improved and sinterability can be improved.

Furthermore, it is desirable that the specific surface area of the inorganic powder is ² to 12 m ² / g in that the sintered density can be stably improved by adding a small amount of phosphorus, and moisture resistance reliability and high ceramic strength can be obtained. .

  An organic binder and an organic solvent are added to the inorganic powder as an organic component and mixed to prepare a slurry. Here, the organic binder may be easily volatilized during the firing process, and may contain an additional plasticizer if desired.

  Examples of the organic binder include acrylic resin, ethyl cellulose resin, butyral resin, and Neugen. Of these, acrylic resins are preferred because they have good thermal decomposability during the firing step and almost no carbon remains.

  Examples of the acrylic resin include an acrylic resin, an acrylic ester copolymer, a methacrylic ester copolymer, and an acrylic ester-methacrylic ester copolymer.

  Moreover, as monomers constituting these, acrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, cyclohexyl acrylate, 2-ethylhexyl acrylate, methacrylic acid, methyl methacrylate, ethyl methacrylate, butyl methacrylate, Examples include cyclohexyl methacrylate and 2-ethylhexyl methacrylate.

  By polymerizing a cyclic ether, a straight chain ether, a long chain ether, a long chain —OH, —OH monomer with respect to these monomers, a cyclic ether, a straight chain ether, a long chain —OH, —OH as a functional group can be obtained. An acrylic resin having at least one of them is obtained.

  Examples of the organic solvent include toluene, xylene, benzene, and isopropyl alcohol. Of these, toluene is preferred because of its good drying property during tape molding and low cost.

  Examples of the plasticizer include DOP (dioctyl phthalate) and DBP (dibutyl phthalate). Among these, DOP is preferable because it is excellent in that it does not easily volatilize during the manufacturing process before the baking process.

  This slurry is used to form on a tape. As a molding method, a known molding method can be used. For example, a doctor blade method or a lip coater method can be used. After tape formation, the sheet is cut to a predetermined size to produce a green sheet.

(Circuit formation process)
Next, a via paste is formed in the green sheet obtained in the forming process by a known drilling method such as punching or laser drilling, and a conductor paste containing Cu and / or Ag inside the through hole of the green sheet. To form a via conductor.

  Next, on the surface of the green sheet, a wiring circuit layer is formed by applying or printing in a circuit pattern to be a surface conductor layer or an internal conductor layer by a screen printing method using a conductor paste containing Cu and / or Ag. To do.

  In this way, a green sheet having via conductors and / or wiring circuit layers is produced.

(Lamination process)
Next, a green sheet having via conductors and / or wiring circuit layers obtained in the circuit forming process and a green sheet in which via conductors and wiring circuit layers obtained in the molding process are not formed are well-known laminates. Laminate by the method. In this case, it goes without saying that the conductor patterns are combined so as to become a predetermined designed circuit. As a lamination condition, 2 to 20 desired green sheets can be stacked, heated to 30 ° C. to 120 ° C., and laminated at a pressure of 10 to 200 kg / cm ² . Further, by performing this process in a vacuum chamber, wrinkles and delamination due to air entrapment can be suppressed.

(Baking process)
Next, the laminate obtained in the lamination step is fired. The firing temperature is preferably 1000 ° C. or lower, which is lower than the melting point of the conductor paste containing Cu and / or Ag which is a low resistance conductor. The firing temperature must be at least the softening point of the glass and needs to be densified by rearrangement of the inorganic powder, but the presence of the phosphorus-containing compound provides good wettability between the glass and the ceramic powder, and rearrangement proceeds. It can be sintered at 850 ° C. Moreover, it is desirable to degrease 90% or more of the organic component in the green sheet at 400 to 700 ° C. in order to promote wettability.

  The manufacturing method of the multilayer wiring board of the present invention can provide a multilayer wiring board having the following characteristics by including the molding step, the circuit formation step, the lamination step, and the firing step.

  Next, the multilayer wiring board of the present invention produced using the above manufacturing method will be described. The multilayer wiring board of the present invention is formed by laminating a ceramic insulating layer having a conductor layer on the surface and inside, an example of which is shown in FIG.

  According to FIG. 1, a multilayer wiring board 1 is formed by laminating seven layers of insulating layers 2, and a cross section thereof is shown. Electrodes and wirings for external connection and chip component mounting by the surface layer conductor 3, circuit patterns such as inductors, capacitors, grounds, wirings, and the like by the inner layer conductor 4, and via-hole conductors 5 for interlayer connection are provided. Moreover, it has the capacitor | condenser part 6 formed with the surface layer conductor enclosed with the broken line, and the inner layer conductor.

  The multilayer wiring board of the present invention is characterized by high porcelain density, high strength and high insulation moisture resistance.

As ceramic powder, MgTiO ₃ powder with a purity of 99% or more, CaTiO ₃ powder with a purity of 95% or more, Al ₂ O ₃ powder with a purity of 98% or more, Mg ₂ SiO ₄ powder, MgO powder and SiO ₂ powder, glass powder, purity of 98% or more of _{B 2 O 3 -SiO 2 -Al 2} O 3 -MgO-BaO glass _{(BAMB), CaO-Al 2} O 3 -MgO-SiO 2 glass (the CAMS) and _BaO-Al 2 O 3 -SiO was prepared ₂ -ZnO glass (BASZ) and _{B 2 O 3 -SiO 2 -Li 2} O-BaO-CaO glass (BSLB). Here, a powder having an inorganic powder having a specific surface area of 10 m ² / g was prepared.

As the phosphorus-containing compound, P ₂ O ₅ powder having a purity of 98% or more, butyl phosphate having a purity of 98% or more, and a phosphate ester having a purity of 98% or more were used.

  13 parts by weight of acrylic resin (isobutyl methacrylate), 10 parts by weight of dibutyl phthalate (DBP) as a plasticizer, and toluene as a solvent with respect to 100 parts by weight of inorganic powder comprising 50% by weight of ceramic powder and 50% by weight of glass 50 parts by mass was added and mixed for 24 hours to form a slurry. This slurry was formed into a thickness of 0.12 mm by the doctor blade method. The acrylic resin has a carboxyl group and an amide group as functional groups.

When powdered P ₂ O ₅ is used as the phosphorus-containing compound, it is added as an inorganic powder, and when a liquid phosphate ester or butyl phosphate dissolved in isopropyl alcohol is used, a slurry is prepared. These liquid phosphorus-containing compounds were added to the slurry and then mixed for 24 hours.

  A through hole is formed at a predetermined position of the green sheet by punching or the like, and the conductive paste containing Ag powder is filled into the through hole, and the conductive paste is screened at a predetermined position on the surface of the green sheet. It printed and dried and produced the green sheet with a conductor. A green sheet filled with a conductive paste and having a conductor layer of a predetermined shape was laminated to produce a laminated molded body having the structure of FIG. Thereafter, the binder removal treatment was performed at 400 ° C. in the atmosphere, followed by firing at 900 ° C. to obtain the glass ceramic wiring substrate shown in FIG.

This wiring board was mirror-polished, and the porosity of the layer sandwiched between the conductors in part a in FIG. 1 was calculated from the SEM image. In addition, for the capacitor part sandwiched between the conductors of 6 parts in FIG. 1 of this wiring board, a DCBT was applied for 400 hours under a vapor pressure of 121 ° C. and 2 atm. Then, the insulation resistance was measured, and the defect rate was calculated by assuming that the insulation resistance was less than 1 × 10 ¹⁰ Ω.

Further, as a sample for strength evaluation, 8 layers of green sheets were laminated and fired in the same manner to obtain a test piece of 5 mm × 40 mm × 0.8 mm. With respect to this test piece, a three-point bending strength was measured at room temperature under conditions of a crosshead speed of 0.5 mm / min and a distance between lower fulcrums of 30 mm. The results are shown in Table 1.

  Sample No. of the present invention. 3-8 and 11-15 had a porosity of 3% or less, a three-point bending strength of 260 MPa or more, and a defect rate after 400 hours of PCBT of 30% or less.

In particular, Sample No. having a P ₂ O ₅ equivalent in the range of 0.04 to 0.20 wt%. Nos. 4 to 7 were particularly good with a porosity of 2% or less, a strength of 290 MPa or more, and a PCBT defect rate of 25% or less.

  On the other hand, Sample No. out of the scope of the present invention in which the content of the phosphorus-containing compound in the slurry is less than 0.02% by mass. In Nos. 1 and 2, the strength was as small as 200 MPa, the porosity was 5%, and the PCBT defect rate was 85% or more.

  Further, the sample No. out of the scope of the present invention in which the content of the phosphorus-containing compound in the slurry exceeds 0.3% by mass. Nos. 9 and 10 had a porosity of 4% or more, a strength of 250 MPa or less, and a PCBT defect rate of 34% or more.

The schematic sectional drawing which shows an example of the ceramic laminated substrate of this invention is shown.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Ceramic multilayer wiring board 2 ... Insulating layer 3 ... Surface layer conductor 4 ... Inner layer conductor 5 ... Via-hole conductor 6 ... Capacitor part

Claims (6)

A forming step of forming a plurality of green sheets formed by forming a slurry containing an inorganic powder and an organic component into a tape shape, forming a via hole in a part of the green sheet, and Cu and / or Ag in the via hole A conductive paste containing a conductive paste is formed to form a via conductor, and the conductive paste is printed on the surface of the green sheet in a circuit pattern to form a wiring circuit layer, and the forming process is used. A lamination process for producing a laminated body by stacking a plurality of green sheets and / or green sheets having via conductors and wiring circuit layers produced in the circuit forming process, and a firing process for firing the laminated body In the manufacturing method of the glass ceramic wiring board to comprise, the said slurry is glass powder containing 2a group and 3a group element as inorganic powder, Al ₂ O _3, and _{CaTiO 3, MgTiO 3, Mg 2} SiO 4, at least one ceramic powder of MgO and SiO _2, and P 2 _{O 5} converted at the 0.02 to 0.30 wt% phosphorus-containing compound And a porosity of the laminate after firing is 1 to 3% .   The phosphorous ester is a phosphoric acid ester, and after preparing a slurry containing the glass powder, the ceramic powder, and the organic component, the phosphoric acid ester is added to the slurry. Manufacturing method of multilayer wiring board.   3. The method for manufacturing a multilayer wiring board according to claim 1, wherein the glass powder contains at least one element selected from Mg, Ca, Sr, and Ba and at least one element selected from B and Al.   The said glass powder is crystallized glass powder, The manufacturing method of the multilayer wiring board in any one of Claims 1-3 characterized by the above-mentioned.   5. The multilayer wiring board according to claim 4, wherein the crystallized glass forms at least one of diopside, celsian, cordierite, anorthite, spinel, mullite, and forsterite after the firing step. Manufacturing method. Claim 1 is produced by the method according to any one of 5, a multilayer wiring board ceramic layer, characterized in that formed by laminating with a surface and inside the conductor layer.

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