JP4782397B2 - Conductive paste and method for manufacturing wiring board using the same - Google Patents

Description

  The present invention relates to a conductor paste and a method for manufacturing a wiring board using the same.

  Conventionally, a wiring board has a structure in which a metallized wiring layer is disposed on or inside an insulating substrate. As a typical example using this wiring board, there is a semiconductor element housing package for housing a semiconductor element, particularly a semiconductor integrated circuit element such as an LSI (Large Scale Integrated Circuit element).

  These semiconductor element storage packages generally use an electrically insulating material such as alumina ceramics, and a plurality of metallized wiring layers made of refractory metal powders such as W and Mo are formed inside and inside the insulating substrate. Has been. Further, a connection pad is formed on the lower surface of the insulating substrate, and an appropriate connection terminal is attached to the connection pad to be electrically connected to the external circuit substrate. A semiconductor element is mounted on the upper surface of the insulating substrate, and this semiconductor element is hermetically sealed by a lid.

  Further, as an insulating substrate in a package for housing a semiconductor element, a ceramic that can be fired at around 1000 ° C. that can be formed of a low resistance metal such as Cu or Ag as a metallized wiring layer in place of the alumina ceramics or the like recently. As a material, an insulating material such as so-called glass ceramics, which is obtained by adding a ceramic filler powder to a glass powder and firing it, has been proposed.

  As a specific method for forming a metallized wiring layer mainly composed of copper on the surface of such an insulating substrate made of glass ceramics, a slurry prepared by adding a glass ceramic raw material powder and a solvent to an organic binder Is formed into a sheet shape by a doctor blade method, etc., and through holes are punched into the obtained green sheet, and a via-hole conductor is formed by filling the through holes with a conductor paste mainly composed of copper. A method in which a conductive paste containing copper as a main component is printed and formed into a wiring pattern by screen printing or the like, and a plurality of green sheets on which wiring patterns or via-hole conductors are formed are pressure-laminated and fired at 800 to 1000 ° C. Is well known.

  When conductor wiring is formed using the copper metallized composition, good conductivity can be ensured.

And as such a conductor paste containing copper as a main component, for example, Al ₂ O ₃ , ZrO ₂ or the like as a metal oxide with respect to the main component Cu or Cu ₂ O, or a Cu—Cu ₂ O mixture, etc. A copper metallized composition containing 0.5 to 30.0% by volume of inorganic components in total has been proposed. (See Patent Document 1).
JP-A-10-95686

  Usually, the firing temperature of the glass ceramic substrate and the copper metallized composition co-fired with it is about 800 to 1100 ° C., but the firing shrinkage start temperature during firing is between the glass ceramic substrate and the copper metallized composition. It is common to shift. Due to this difference in firing shrinkage start temperature, a stress is generated between the glass ceramic substrate and the copper metallization, and the substrate is warped or deformed. In addition, the via hole conductor is raised, cracked, etc. in the through hole, resulting in a problem of poor contact and structural defects of the substrate. In addition, problems such as warpage and deformation of the wiring board also occur due to the difference in firing shrinkage between the glass ceramic substrate and the copper metallized composition.

In order to suppress the warping of the wiring board against such problems, it is necessary to match the firing shrinkage start temperature in the copper metallized composition and the ceramic green sheet, for example, sintering of the copper metallized composition In order to delay the process, Al ₂ O ₃ , Ni or the like, which is a hardly sintered material, was added to the copper paste. For example, in order to accelerate the sintering of the copper metallized composition, a low softening point glass has been added.

  As a result, the metal oxide or glass is exposed on the surface of the metallized wiring layer, leading to reduced plating properties, decreased appearance yield, decreased adhesion strength of the metallized wiring layer to the insulating substrate, and increased conductor resistance. . Conversely, when all of the plating properties, appearance, adhesive strength, conductor resistance, and the like are considered, it has been difficult to suppress substrate warpage.

  Further, in a method for suppressing substrate warpage by matching the difference in firing shrinkage between the copper metallized composition and the ceramic grease sheet, it is common to mix an appropriate amount of cuprous oxide powder as the copper metallized composition. This is because the difference in firing shrinkage between the glass ceramic substrate and the copper metallized composition is small due to the volumetric shrinkage caused by the reduction of cuprous oxide to copper in a reducing atmosphere and the shrinkage accompanying the densification of the metallized. This is because the warpage and deformation of the substrate are suppressed, but there is a limit to the suppression effect.

  The conventional cuprous oxide powder has a non-spherical shape such as a dendritic shape, a flake shape, and a star shape with projections in many directions as shown in FIG. there were. Since these conventional cuprous oxide powders have the above-described shape, they are reduced while the contact is maintained between the adjacent cuprous oxide powder and the protrusions, and further densification occurs. At this time, there is a lot of space for the concave portions where the cuprous oxide powders do not contact each other, and the densification is completed in a state where the gaps are left. Therefore, although volume shrinkage occurs due to firing shrinkage, a portion corresponding to the gap is not compensated, so that the shrinkage amount is smaller than that of a spherical powder shrinking well. Therefore, these conventional non-spherical cuprous oxide powders have not been sufficiently effective to match the difference in firing shrinkage between the copper metallized composition and the ceramic grease sheet and to suppress the warpage of the substrate.

  Therefore, the present invention improves the consistency between the volume shrinkage and firing shrinkage start temperature of copper metallized and ceramic green sheets, and a conductor paste capable of dramatically suppressing deformation such as warping and waviness of the wiring board, and It aims at providing the manufacturing method of the used wiring board.

Conductive paste of the present invention, spherical shape of the cuprous oxide powder, copper powder, a conductive paste made of a resin and glass powder, wherein the cuprous oxide powder has an average particle size (D50) is at 4μm or less, ( and has a particle size distribution which satisfies the D90-D10) / D50 ≦ 2 , BET specific surface area of not more than ^{15 m} 2 / g, an average particle size of the copper powder (D50) is characterized in der Rukoto below 6μm .

  Moreover, as for the conductor paste of this invention, it is desirable that the ratio of the said copper powder and the said cuprous oxide powder is 5: 95-40: 60 by mass ratio.

The method for producing a wiring board according to the present invention includes applying the conductive paste according to any one of the above to a surface of a ceramic green sheet containing at least ceramic powder and a resin, or in a through hole formed in the ceramic green sheet. It comprises a conductor forming step for printing or filling , and a firing step for firing the ceramic green sheet on which the conductor paste is printed or filled.

  Further, the method for manufacturing a wiring board of the present invention includes a laminating step of laminating a plurality of ceramic green sheets printed or filled with a conductor paste by the conductor forming step between the conductor forming step and the firing step. It is desirable to do.

  In the conductor paste of the present invention, the cuprous oxide powder has a spherical shape, so that the cuprous oxide powder has a volumetric shrinkage due to reduction shrinkage and densification while maintaining a uniform and high filling with the adjacent cuprous oxide powder. Occur. As a result, the gap between the particles after completion of the contraction is minimized, so that a high contraction amount is ensured. Therefore, the amount of shrinkage can be remarkably increased compared with the case of using conventional non-spherical cuprous oxide powder, and the difference in firing shrinkage between the glass ceramic substrate and the copper metallized composition can be further reduced. Become. Therefore, the consistency of the shrinkage amount of both can be effectively enhanced. Moreover, in terms of firing shrinkage starting temperature, it can be delayed compared with the case of using non-spherical cuprous oxide powder, firing shrinkage starting temperature in the glass ceramic substrate and the copper metallized composition can be brought closer, warping of the substrate and Deformation can be suppressed.

  In addition, since the gap between the particles after completion of the shrinkage is suppressed and a dense metallized structure is formed, the conductor resistance can be lowered and a wiring layer having good plating properties can be obtained. As a result, it is possible to prevent the wiring layer from being peeled off, so that the adhesive strength between the insulating substrate and the copper wiring layer can be maintained high.

  Further, by including copper powder in the conductor paste, it is possible to freely control the matching of the volume shrinkage during firing of the metallized and ceramic green sheets.

  In addition, by including glass powder in the conductor paste, the glass whose viscosity has been reduced in the baking process penetrates into the gaps between the copper particles in the copper metallized composition, and as a result, the adhesive strength between the insulating substrate and the copper wiring layer is increased. Can be improved.

  Moreover, by making the average particle diameter (D50) of the cuprous oxide powder 4 μm or less, the cuprous oxide powder is uniformly dispersed in the paste, and by reducing and sintering the cuprous oxide powder, there is no void and it is dense. Become a metallization organization. As a result, the volumetric shrinkage ratio at the time of firing the metallization becomes substantially equal to the volumetric shrinkage ratio at the time of firing the ceramic green sheet, and effective warpage suppression is obtained. Moreover, high conductivity is ensured in the conductor wiring due to the dense structure.

Moreover, regarding the average particle diameter (D50) of the said copper powder, it is important to set it as 6 micrometers or less. This is because, in order to form a dense thick-film copper conductor even when baked at 800 ° C. to 1000 ° C., copper powder having a certain particle size or less is required. That is, in the copper powder having a 6μm average particle size of less than improves the sintering property becomes possible high packing density without voids, a dense metallization tissue. As a result, the volumetric shrinkage ratio at the time of firing the metallization becomes substantially equal to the volumetric shrinkage ratio at the time of firing the ceramic green sheet, and effective warpage suppression is obtained. Moreover, high conductivity is ensured in the conductor wiring due to the dense structure.

Further, in the particle size distribution of the cuprous oxide powder, (D90-D10) / D50 2 By satisfying ≦, said by cuprous oxide powder is more uniform particle size, capable of high filling without voids It becomes. As a result, a dense metallized structure is obtained, and the volumetric shrinkage rate during firing of the metallized metal becomes substantially equal to the volumetric shrinkage rate during firing of the ceramic green sheet, and effective warpage suppression can be obtained.

Further, the specific surface area of the cuprous oxide powder and 15 m 2 / ^g or less and to Turkey, improved sinterability of cuprous oxide powder, and pores in the metallizing tissue is reduced, conductor wiring conductor Resistance can be reduced.

  Further, by mixing the copper powder and the cuprous oxide powder at a predetermined ratio shown by a mass ratio of 5:95 to 40:60, the difference in shrinkage between the conductor paste and the ceramic green sheet is reduced, and insulation is achieved. It is possible to effectively prevent deformation such as warpage and undulation of the substrate.

  Further, according to the method for manufacturing a ceramic wiring board according to the present invention, the surface of the ceramic green sheet containing the ceramic powder containing glass powder and the resin or the through-hole formed in the ceramic green sheet is as described above. Forming a conductive paste, and further including a firing step of firing the ceramic green sheet on which the conductive paste is formed, so that deformation such as warping and undulation of the substrate is extremely small, low resistance, and A wiring substrate having high copper wiring layer adhesion strength and good plating properties can be produced.

  Furthermore, a multilayer wiring board can be easily manufactured by providing a further lamination step.

  Hereinafter, the contents of the present invention will be described in detail with reference to the accompanying drawings shown in the embodiments. FIG. 1 shows an example of a wiring board according to the present invention, which has a basic structure of a so-called wiring board in which a metallized wiring layer is disposed on or inside an insulating substrate. It is a schematic sectional drawing of the package for semiconductor element accommodation mentioned as a typical example.

  1 includes an insulating substrate 1, a lid 2, a metallized wiring layer 3, a connection terminal 4, and a semiconductor element 5 accommodated inside the package. The insulating substrate 1 and the lid 2 are made of a semiconductor. A container 6 for accommodating the element 5 in an airtight manner is formed. That is, the semiconductor element 5 is placed and accommodated on the upper surface of the insulating substrate 1, and the semiconductor element 5 is bonded and fixed to the insulating substrate 1 via an adhesive such as glass or resin.

  A plurality of metallized wiring layers 3 are deposited on the insulating substrate 1 from the periphery on which the semiconductor element 5 is placed to the lower surface, and a number of connection pads 4 a are provided on the lower surface of the insulating substrate 1. And is electrically connected to the metallized wiring layer 3. A protruding terminal 4b made of a brazing material such as solder (tin-lead alloy) is attached to the surface of the connection pad 4a as a connection terminal to an external circuit board (not shown).

  As a method for attaching the protruding terminals 4b, there are a method in which spherical or columnar brazing materials are arranged on the connection pads 4a and a method in which a brazing material is printed on the connection pads 4a by a screen printing method.

  The metallized wiring layer 3 electrically connected to the connection pad 4a is electrically connected to each electrode of the semiconductor element 5 via a bonding wire, so that the electrode of the semiconductor element 5 is connected to the connection pad 4a. It will be electrically connected.

  In the present invention, it is important to use spherical cuprous oxide powder for the conductor paste that becomes the metallized wiring layer 3 by firing.

  That is, the present invention is characterized in that a cuprous oxide powder that has been conventionally used is non-spherical, whereas a spherical one whose crystal shape cannot be discriminated as shown in FIG. 2 is used. Specifically, to determine whether the cuprous oxide powder is non-spherical or spherical, select any 20 cuprous oxide powders from the image of the electron micrograph, and use an image analyzer for each particle. Judged by measurement.

For example, when cuprous oxide powder is fired in a non-oxidizing atmosphere such as H ₂ O + N ₂ ,
Cu ₂ O → 2Cu + 1 / 2O ₂
This occurs, and the volume shrinks due to reduction and sintering of the cuprous oxide powder. The spherical cuprous oxide powder described above has a relatively small space that can be brought into contact with the protrusions as seen in non-spherical powder, and by taking a high filling state, the amount of firing shrinkage accompanying reduction shrinkage and densification And the consistency of the difference in firing shrinkage between the glass ceramic substrate and the copper metallized composition can be effectively enhanced.

In addition, the cuprous oxide powder, Ri average particle diameter (D50) 4 [mu] m der or less and further preferably to 2μm or less.

  Further, by satisfying (D90−D10) / D50 ≦ 2 in the particle size distribution of the cuprous oxide powder, the low resistance characteristic of the conductor wiring and the suppression of the warp of the substrate become more effective.

In addition, the cuprous oxide powder state, and are specific surface area of ^{15 m} 2 / g or less, it is desirable to more preferably at most ^12m 2 / g. This is because when the specific surface area exceeds a predetermined range, pores in the metallized structure increase and the conductor resistance of the conductor wiring increases, thereby impairing conductivity.

  By mixing the copper powder and cuprous oxide powder at a predetermined ratio, the shrinkage difference between the conductor paste and the ceramic green sheet can be reduced, and deformation such as warping and undulation of the insulating substrate can be effectively prevented. it can. That is, the mixing ratio of the copper powder and the cuprous oxide powder is preferably 5:95 to 40:60 by mass ratio. More preferably, the ratio is 15:85 to 30:70. This is because when the ratio of the cuprous oxide powder is less than 60, the amount of contraction of the conductive paste is smaller than the amount of contraction of the ceramic green sheet, so that the effect of suppressing warpage of the insulating substrate is not sufficient. On the other hand, when the ratio of the cuprous oxide powder is larger than 95, voids in the metallized structure increase, the conductor resistance of the conductor wiring is increased, and the conductivity is impaired. In addition, the adhesive strength between the insulating substrate 1 and the metallized wiring layer 3 is lowered, and the plating property of the metallized wiring layer 3 is lowered.

  Moreover, regarding the average particle diameter of the said copper powder, it is important to set it as 6 micrometers or less. This is because, in order to form a dense thick-film copper conductor even when baked at 800 ° C. to 1000 ° C., copper powder having a certain particle size or less is required. That is, when copper powder having an average particle diameter of less than 6 μm is used, a sufficient wiring conductor can be obtained because sufficient sinterability is ensured even if a space is obtained by reduction of the cuprous oxide powder. is there.

  A method for manufacturing a wiring board according to the present invention will be described below.

  First, an organic resin binder having an appropriate shape is added to a mixture of glass powder and filler, and then formed into an arbitrary shape into a sheet shape by a desired forming means such as a doctor blade, a rolling method, a die press, or the like. After that, for example, the conductor paste of the present invention is formed into an arbitrary shape by screen printing or the like on the main surface of the sheet-like ceramic green sheet or the through-hole formed in the ceramic green sheet. The blended organic resin binder component is removed by heat treatment in an air atmosphere at around 700 ° C. At this time, the shrinkage start temperature of the molded body is preferably about 700 to 850 ° C., and if the shrinkage start temperature is lower than this, it becomes difficult to remove the binder. It is necessary to control the yield point as in the present invention.

  Firing is performed in an oxidizing atmosphere at 850 ° C. to 1050 ° C., thereby densifying to a relative density of 90% or more. If the firing temperature at this time is lower than 850 ° C., it cannot be densified, and if it exceeds 1050 ° C., the metallized wiring layer is melted by simultaneous firing with the metallized wiring layer 3.

  However, when copper is used as a conductor for wiring, it is performed in a non-oxidizing atmosphere at 850 to 1050 ° C.

  Needless to say, a multilayer wiring board can be obtained by laminating ceramic green sheets as necessary.

  In the glass-ceramic sintered body thus prepared, there are a crystal phase generated from crystalline glass, a crystal phase generated by the reaction between glass and filler, or a crystal phase generated by decomposition of filler components. A glass phase is present at the grain boundaries of these crystal phases.

  Further, in order to manufacture a wiring board in which the metallized wiring layer 3 made of copper is disposed on the surface of the insulating board 1 made of glass ceramic, it is made of glass and filler as described above for constituting the insulating board 1. A suitable organic binder, a plasticizer, and a solvent are added to the raw material powder to make a slurry, and the slurry is made into a green sheet (raw sheet) by employing a doctor blade method or a calendar roll method.

  And glass powder is mixed with copper powder and cuprous oxide powder for metallized wiring layer 3 and connection pad 4a. Desirably, glass is mix | blended in the ratio of 0.5-4 mass parts with respect to 100 mass parts of metal components. Then, an organic binder, a plasticizer, and a solvent are added to the mixture and mixed to prepare a metallized paste.

  Then, this metallized paste is printed on the green sheet in a predetermined pattern by a well-known screen printing method. In some cases, the green sheet is appropriately punched to form a through hole, and the hole is filled with the metallized paste. A plurality of these green sheets are laminated.

  Thereafter, the laminate is heat-treated in a nitrogen atmosphere containing water vapor at 500 to 700 ° C. to remove the organic resin binder, and then fired in a non-oxidizing atmosphere such as nitrogen at 850 ° C. to 1050 ° C. for insulation. Baking until the substrate is densified to a relative density of 90% or higher.

  Thereafter, the wiring board can be completed by forming a plating layer of Cu, Au, Ni or the like on the surface of the metallized wiring layer 3 of the wiring board by electrolytic plating or electroless plating.

_First, SiO 2: 50.2 _{wt%, Al} 2 O 3: 5.0 wt%, CaO: 15.1 wt%, MgO: 16.1 wt%, SrO: Mean having a composition of 13.6 wt% Crystalline glass A powder having a particle size of 3 μm (softening point 850 ° C.) was prepared, and Al ₂ O ₃ having an average particle size of 2 μm was prepared as a filler component for this glass so that the mass ratio was 60:40. . With respect to 100% by mass of the glass ceramic raw material powder A, 11% by mass of p-isobutyl methacrylate resin as an organic binder and 5% by mass of dibutyl phthalate as a plasticizer are added and mixed for 36 hours by a ball mill using toluene as a solvent. The slurry was adjusted. A green sheet having a thickness of 0.2 mm was formed from the obtained slurry by a doctor blade method.

  Furthermore, copper powder having an average particle diameter of 5 μm and 2 μm was prepared. Then, a cuprous oxide powder having the characteristics shown in Table 1 having an average particle diameter of 4 μm or 2.5 μm was weighed and added to each copper powder at a ratio shown in Table 1. And the crystalline glass powder used for formation of the said insulated substrate whose average particle diameter is 3.5 micrometers with respect to 100 mass% (Cu conversion) was added to this copper powder in the ratio of 2 mass%. Further, 2% by mass of acrylic resin as an organic binder and 15% by mass of cuprous oxide powder-terpineol as an organic solvent were added and kneaded to 100% by mass of these inorganic components to prepare a conductor paste.

  The conductor paste thus obtained was screen-printed on the glass ceramic green sheet in a pattern for copper metallized wiring having a shape of 1 × 1 cm square and a thickness of about 15 μm after firing, and four green sheets were added to the bottom. The pressure-laminated product is used as a monitor for measuring plating properties and insulation substrate warpage, and is screen-printed in a pattern for copper wiring having a shape after firing of 2 mm □ and a thickness of about 15 μm. A laminate obtained by pressurizing the sheets was used as a sample for measuring the adhesive strength between the metallized wiring layer and the insulating substrate. In addition, screen printing was performed on a copper wiring pattern with a width of 0.1 mm, a length of 50 mm, and a thickness of about 15 μm after firing, and three green sheets were stacked on the top and two green sheets were patterned on the bottom. This was used as a conductor resistance sample.

  Next, after degreasing the laminate on which the wiring pattern in an unsintered state is formed, by holding it at a temperature of 700 ° C. for 3 hours in a steam-containing nitrogen atmosphere in order to decompose and remove organic components such as an organic binder. Then, the temperature was raised to 910 ° C. in a nitrogen atmosphere and held for 1 hour to produce a wiring board.

  The warp measurement monitor measured the X and Y directions with a surface roughness meter, and the average value was determined to be 50 μm / 10 mm □ or less.

  The adhesive strength measurement monitor performs Ni plating with a thickness of 1 μm on the copper wiring layer of the wiring substrate, Au plating with a thickness of 0.1 μm thereon, a flux is applied on the Ni plating, and Sn / A Pb eutectic solder ball was placed thereon and held in the atmosphere at 5 ° C. for 1 minute to perform solder ball attachment. Then, the maximum load when the copper wiring layer was broken by holding the solder ball with a clamp pull strength measuring machine in the vertical direction was evaluated as the adhesive strength of the copper wiring layer. In addition, as a judgment of pass / fail, the case where the minimum value of the maximum load exceeded 9 kgf / 2 mm □ was determined as non-defective.

  Also, the same plating as the adhesive strength measurement monitor was applied to the warp measurement monitor, and if the plating surface was plated with 98% or more of the whole, it was evaluated as ○, 80 to 98% as Δ, and 80% or less as ×. .

  The conductor resistance monitor measured the resistance (μΩ · m) between both ends of the pattern, and if it was less than 3 μΩ · m, it was judged as a good product.

The above measurement results are shown in Table 1.

  Sample No. which is outside the scope of the present invention using the conventional cuprous oxide powder having a non-spherical shape and a large specific surface area. In Nos. 4 and 5, the warping amounts were very large as 164 μm and 95 μm, and the bonding strength was low. Furthermore, the conductor resistance is 3 μΩ · m or more, the conductivity is low, the plating property is lowered, and it cannot be used at all.

On the other hand, when the conductor paste of this invention was used, the curvature amount could be suppressed to less than 50 micrometers, and the favorable result was obtained in joining strength, plating property, and conductor resistance.

  In particular, no. 15, no. As shown in FIG. 16, the ratio of the cuprous oxide powder having an average particle diameter of 2.5 μm and the copper powder having an average particle diameter of 2.0 μm is 75:25, so that the amount of warpage can be reduced to less than 30 μm. did it.

No. Even if the specific surface area of the cuprous oxide powder is 15 m ² / g or less as in 1, the amount of warpage can be reduced to less than 30 μm when the ratio of the cuprous oxide powder to the copper powder is 100: 0. The conductor resistance was a relatively high value of 2.9 μΩ · m. No. When the ratio of the cuprous oxide powder to the copper powder is changed to 50:50 as in 20, the conductor resistance is extremely low as 1.9 μΩ · m, but the warping amount is slightly increased to 48 μm. Obtained. Therefore, in order to obtain good results in both evaluation items, it was found that the ratio of the cuprous oxide powder and the copper powder is more preferably in the range of 95: 5 to 60:40.

It is the schematic of the package for semiconductor element absorption which is a typical example of the wiring board of this invention. It is a scanning electron micrograph of the spherical cuprous oxide powder used for the conductor paste of this invention. It is a scanning electron micrograph of the non-spherical cuprous oxide powder which is the conventional cuprous oxide powder.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Insulation base | substrate 2 ... Cover body 3 ... Metallized wiring layer 4 ... Connection terminal 5 ... Semiconductor element 6 ... Container

Claims (4)

Spherical shape of the cuprous oxide powder, copper powder, a conductive paste made of a resin and glass powder, wherein the cuprous oxide powder has an average particle size (D50) is at 4μm or less, (D90-D10) / D50 ≦ and has a particle size distribution satisfying the 2, a BET specific surface area of ^{15 m} 2 / g or less, the copper powder having an average particle size (D50) of the conductor paste, wherein der Rukoto below 6 [mu] m. Ratio of the cuprous oxide powder and the copper powder, a mass ratio of 5: 95 to 40: 60 a conductive paste according to claim 1, characterized in that. A conductor forming step of printing or filling the conductor paste according to claim 1 or 2 on the surface of a ceramic green sheet containing at least ceramic powder and a resin, or in a through-hole formed in the ceramic green sheet; And a firing step of firing a ceramic green sheet printed or filled with a conductive paste.   4. The method according to claim 3, further comprising a laminating step of laminating a plurality of ceramic green sheets on which a conductor paste is printed or filled in the conductor forming step between the conductor forming step and the firing step. A method for manufacturing a wiring board.

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