JP2019046590A - Conductive paste and manufacturing method of ceramic wiring board - Google Patents

Abstract

To provide a conductive paste high in stability of a state of the conductive paste, and a manufacturing method of a ceramic wiring board capable of suppress deformation of the ceramic wiring board when the ceramic wiring is manufactured by using the conductive paste.SOLUTION: A conductive paste has D50 particle diameter in a range of 0.7 μm to 0.9 μm as particle size of a powder of W in the conductive paste, and a ratio of Cu in a conductive component of 5 pts.wt. to 70 pts.wt. when the conductive component is 100 pts.wt. Thereby phenomenon such as gelatinization of the conductive paste is hardly generated. Then phenomenon such that the conductive paste becomes hard or film is generated on a surface. Since the state of the conductive paste is stable, a fine wiring or the like can be easily formed by screen printing or the like even when long time is passed from manufacturing the conductive paste.SELECTED DRAWING: Figure 1

Description

  The present disclosure relates to a method of manufacturing a conductive paste and a ceramic wiring substrate that can be used in the fields of, for example, packages of electronic components, wireless communication module substrates, substrates for control circuits, and semiconductor inspection devices.

  Conventionally, low resistance and relatively inexpensive Cu-based materials have been used for various substrates such as ceramic wiring substrates as conductive materials constituting wiring and the like. In addition, Ag and Au are also used as similar low-resistance conductive materials.

  However, conductive materials such as low resistance Cu, Ag, Au have the property of having a low melting point. Therefore, if, for example, glass ceramic is used as a substrate material capable of co-firing with these conductive materials, there is a problem that the strength of the substrate is low and another problem that the thermal conductivity is low.

  Therefore, a technology has been developed in which a conductive material such as Cu having a low melting point and a conductive material such as Mo or W having a high melting point are combined and co-fired with a ceramic material such as alumina having high strength and high thermal conductivity. . That is, there is known a technique of forming a wiring pattern on a ceramic green sheet using the ceramic material using a conductive paste containing the low melting point and high melting point conductive material, and co-firing them.

For example, Patent Document 1 discloses a wiring substrate using a Cu electrode containing W or Mo having an average particle diameter of 1 to 10 μm.
In addition, Patent Document 2 discloses a wiring board that uses W or Mo having an average particle size of 1 to 10 μm, and uses a Cu electrode containing a metal oxide having an average particle size of 150 μm or less for shape retention of the wiring. Is disclosed.

JP, 2000-188453, A JP, 2009-4515, A

  By the way, in the above-mentioned prior art, in order to form a Cu-based wiring containing, for example, W or the like, a Cu-based conductive paste containing powder of W or the like having an average particle diameter of 1 μm or more is produced. There was a problem and the improvement was called for.

  Specifically, for example, when a Cu-based conductive paste is produced using powder of W having an average particle diameter of 1 μm or more, the conductive paste may gel or a film may be formed on the surface as time passes. There was something I could do.

  That is, since the phenomenon that the viscosity of the conductive paste increases (that is, thickening) and becomes hard or a film is formed on the surface occurs, there is a problem that the state of the conductive paste is not stable. Therefore, in the conductive paste in such a state, it has been difficult to form, for example, fine wiring or the like by screen printing.

  In addition, when using a Cu-based conductive paste containing powder of W having an average particle diameter of 1 μm or more described above, the shrinkage rate at firing of the wiring pattern (that is, firing ratio of the wiring) It is very small compared to the shrinkage rate during firing (that is, the firing rate of the ceramic substrate). Specifically, the shrinkage factor at the time of firing of the wiring pattern is, for example, much smaller than that at the time of firing of a ceramic green sheet containing a ceramic material such as alumina generally used. That is, the firing ratio of the wiring and the firing ratio of the ceramic substrate are separated.

  Therefore, when the wiring patterns are arranged asymmetrically in the ceramic green sheet or the laminate thereof, for example, when the arrangement of the wiring patterns is uneven in the thickness direction or the planar direction of the laminate, the ceramic wiring after firing Deformation such as warpage may occur on the substrate.

  The present disclosure has been made in view of the above problems, and an object thereof is to manufacture a ceramic wiring substrate using a conductive paste having high stability of the state of the conductive paste and the conductive paste. An object of the present invention is to provide a method of manufacturing a ceramic wiring substrate which can suppress deformation of the ceramic wiring substrate.

(1) A first aspect of the present disclosure relates to a conductive paste including a powder of Cu and a powder of W as a conductive component.
In this conductive paste, the particle size of the W powder is such that the D50 particle diameter is in the range of 0.7 μm to 0.9 μm, and the ratio of Cu in the conductive component is 5 when the conductive component is 100 parts by weight. It is part by weight to 70 parts by weight.

  In the first aspect, the particle size of the powder of W in the conductive paste is such that the D50 particle diameter is in the range of 0.7 μm to 0.9 μm, and when the conductive component is 100 parts by weight, Since the ratio of Cu is 5 parts by weight to 70 parts by weight, phenomena such as thickening due to gelation are less likely to occur, as is apparent from the experimental examples described later.

  That is, since the phenomenon that the conductive paste becomes hard or a film can not be easily generated, the state of the conductive paste is stable. Therefore, even if a long time has passed since the production of the conductive paste, for example, fine wiring and the like can be easily formed by screen printing or the like.

  Specifically, in the first aspect, since the D50 particle size of the powder of W in the conductive paste is 0.9 μm or less, the function of suppressing thickening or the like due to gelation of the conductive paste is high. That is, although resin, such as a binder, is used for the electroconductive paste as a component for paste-ization, reaction of this resin and Cu is considered to be factors, such as gelatinization. Therefore, in the first aspect, it is considered that this fine W suppresses the reaction between the resin and Cu by using a fine W powder having a D50 particle size of 0.9 μm or less. That is, it is estimated that fine W powder contributes to the state stabilization of the conductive paste.

  As described above, in the first aspect, the formation of the fine wiring pattern is facilitated by stabilizing the state of the conductive paste. In addition, since the conductive paste can be stored for a fixed period of time after preparation, mass production becomes possible, which contributes to cost reduction. Furthermore, in order to control the molten state of the powder, etc., special processes such as coating on the surface of the powder can be omitted, which is advantageous in cost. In addition, since it is not necessary to change the organic composition of the conductive paste, there is also an advantage that the influence on the ceramic green sheet and the influence on the green processability are small.

Further, in the first aspect, since the D50 particle size of the W powder is 0.7 μm or more, there is an advantage that there is little risk such as ignition of the powder, and the handling is easy.
Furthermore, in the first aspect, since the ratio of Cu is 5 parts by weight or more, the electrical characteristics (for example, specific resistance) of the wiring formed using the conductive paste are smaller than when the ratio of Cu is smaller than that. The characteristic of being small) is excellent.

Further, in the first aspect, since the ratio of Cu having a low melting point is 70 parts by weight or less, there is an advantage that the shape retention of the wiring is high at the time of firing, and Cu extrusion can be suppressed.
In addition, as a ratio of Cu in a conductive component, the range of 20 weight part-70 weight part is suitable. Specifically, when the ratio of Cu is 20 parts by weight or more, the electrical characteristics of the wiring are further excellent (for example, since the specific resistance is sufficiently small), it is preferable.

(2) A second aspect of the present disclosure relates to a method of manufacturing a ceramic wiring substrate.
In this method of manufacturing a ceramic wiring substrate, the step of forming a wiring pattern on the ceramic green sheet using the conductive paste of the first aspect, the step of simultaneously firing the ceramic green sheet and the wiring pattern, and wiring on the ceramic substrate Manufacturing the provided ceramic wiring substrate.

  In the second aspect, since the wiring pattern is formed on the ceramic green sheet using the conductive paste described above, and simultaneous firing is performed, there is an effect that deformation such as warpage of the ceramic wiring substrate can be suppressed.

  Specifically, since the conductive paste contains W powder having a D50 particle size of 0.9 μm or less, that is, since the particle size of the W powder is small, the particle size of the W powder is larger than that of the W powder. W is easier to be fired than when it is large. Therefore, the shrinkage ratio of the wiring pattern is large at the time of baking, in other words, the ratio of baking of the wiring is large.

Therefore, since the firing ratio of the wiring approaches the firing ratio of the ceramic substrate, it is possible to suppress the occurrence of deformation such as warpage in the ceramic wiring substrate.
Thus, in the second aspect, by changing the particle size of the powder of W in the conductive paste to be used, it is possible to improve the separation of firing ratio without affecting the electrical characteristics of the wiring. Thus, there is a remarkable effect that the warped shape of the product can be improved.

  In particular, compared with alumina materials generally used in MTCC (that is, a ceramic material co-fired with an electrode material in a temperature range of 1000 ° C. to 1400 ° C.), Cu containing W has a large difference in firing ratio. In the second aspect of the present invention, such deviation of the firing ratio can be improved, and the amount of warpage can be greatly reduced.

(3) In the third aspect of the present disclosure, the average particle size of W in the wiring may be in the range of 0.7 μm to 1.2 μm.
In the third aspect, since the average particle diameter of W in the wiring is 1.2 μm or less, for example, a powder of W having a small particle diameter such as a D50 particle diameter of 0.9 μm or less may be used as a wiring material it can. Therefore, as described above, since the firing of W is easy, the firing rate of the wiring is close to the firing rate of the ceramic substrate. As a result, there is an effect that deformation such as warpage of the ceramic wiring substrate is small.

  Further, in the third aspect, since the average particle diameter of W in the wiring is 0.7 μm or more, for example, a powder of W having a suitable particle diameter such as a D50 particle diameter of 0.7 μm or more is used as a wiring material. It can be used. Therefore, as described above, since the handling of the powder is high, there is an advantage that the manufacture of the ceramic wiring substrate is easy.

Hereinafter, each configuration of the present disclosure will be described.
-In addition to the conductive component, the conductive paste contains, for example, a resin binder, a solvent, and the like as a component for forming a paste.

  -As a conductive component, the structure which has Cu and W as a main component is employable. In addition to Cu and W, other conductive components (for example, Mo) may be contained as the conductive component. Here, the main component indicates a component with the largest amount (ie, volume).

  The D50 particle diameter is a diameter (so-called median diameter) at which the large side and the small side become equal when the powder is divided into two from a certain particle diameter. The D50 particle size can be determined by an air permeation method.

The ceramic green sheet is an unfired sheet mainly composed of ceramic as a solid component and further containing a component constituting the sheet.
The ceramic substrate refers to a substrate containing ceramic as a main component. Examples of the ceramic include alumina, zirconia, aluminum nitride and silicon nitride. The ceramic substrate may contain, in addition to the ceramic, a sintering aid such as SiO ₂ , MgCO ₃ or BaCO ₃ .

Wiring is a conductive portion disposed on the surface or inside of the ceramic substrate.
The wiring pattern contains, in addition to the conductive material contained in the conductive paste, a component for forming a pattern such as a binder.

  The average particle size of the wire can be determined from an image of the cross section of the wire taken by, for example, a scanning electron microscope (SEM).

It is sectional drawing which fractures and shows the ceramic wiring board of embodiment in the thickness direction. It is explanatory drawing which shows the manufacturing method of the ceramic wiring board of embodiment. It is sectional drawing which fractures | ruptures and shows the laminated body of Experimental example 2 in the thickness direction. FIG. 14 is an explanatory drawing showing a method of calculating the average particle diameter of W particles on the fracture surface of the wiring of Experimental Example 2;

Next, an embodiment of a method of manufacturing a conductive paste and a ceramic wiring substrate of the present disclosure will be described.
[1. Embodiment]
[1-1. Configuration of Ceramic Wiring Board]
First, a ceramic wiring substrate manufactured using the conductive paste of the embodiment will be described.

As schematically shown in FIG. 1, the ceramic wiring board 1 in the embodiment has an internal wiring layer 5 mainly composed of Cu and W, for example, inside the ceramic substrate 3 containing 90 volume% or more of Al ₂ O _3. Have. The ceramic substrate 3 may be provided with other wiring or via or the like on the surface or the like, but is omitted here.

  In the ceramic wiring board 1, the internal wiring layer 5 which is a wiring is disposed asymmetrically. That is, when the ceramic wiring substrate 1 is broken in the thickness direction, the arrangement of the wirings is asymmetric in the thickness direction (that is, the vertical direction in FIG. 1) on the broken surface. In more detail, the internal wiring layer 5 is disposed on the surface side of one side (upper side in FIG. 1) of the ceramic substrate 3.

Each component will be described below.
The ceramic substrate 3 includes a first ceramic layer 7 and a second ceramic layer 9, and the internal wiring layer 5 is disposed between the first ceramic layer 7 and the second ceramic layer 9.

The ceramic substrate 3 contains, in addition to Al ₂ O ₃ , components of a sintering aid such as SiO ₂ , MgCO ₃ , BaCO _{3 and the} like.
The internal wiring layer 5 contains, for example, components such as Al ₂ O _{3 in} addition to the conductive components Cu and W. The average particle diameter of W particles (that is, crystal particles) in the internal wiring layer 5 is in the range of 0.7 μm to 1.2 μm.

[1-2. Method of manufacturing ceramic wiring board]
Next, a method of manufacturing the ceramic wiring board 1 of the present embodiment will be described. The order of the following first and second steps may be reversed.

<Production Process of Conductive Paste: First Process>
As a main raw material of the internal wiring layer 5, Cu powder and W powder were prepared, and Al ₂ O ₃ powder was prepared. Here, the particle size of the W powder is such that the D50 particle size is 0.7 μm to 0.9 μm. In addition, as particle size of Cu powder, D50 particle diameter can employ | adopt 2.5 micrometers-4.5 micrometers. As the particle size of the _Al 2 _{O 3} powder, average particle size can be adopted as the 150nm or less.

The following describes how to obtain an average particle size of the _Al 2 _{O 3} powder.
After placing 0.1 g of Al ₂ O ₃ (alumina) powder on a stainless steel plate and subjecting it to carbon sputtering, the surface was photographed with a scanning electron microscope (SEM) at a magnification of 1000 ×. The SEM image was used to measure the length of a reference length (for example, a length [mm] corresponding to 1 μm). Next, actually, the length of the alumina particle (alumina particle length A) was measured at 100 points (100 points) in the same direction from the SEM image. And actual alumina particle diameter [nm] was computed using a following formula (1).

Actual alumina particle size [nm] = alumina particle length A [mm] / reference length [mm] · · · (1)
Next, the average of the 100 actual alumina particle sizes determined in this manner was calculated, and this value was defined as the average particle size.

  And a varnish component was added to these powder materials, and the conductive paste for internal wiring layers was produced. In addition, when producing this electroconductive paste, when making Cu and W which are electroconductive components into 100 weight part, the ratio of Cu in an electroconductive component was 5 weight parts-70 weight parts.

<Production process of ceramic green sheet: second process>
First, an Al ₂ O ₃ powder was prepared as a main raw material (a raw material to be a main component) of the ceramic substrate 3, and a powder of SiO ₂ , MgCO ₃ , BaCO ₃ or the like was prepared as a sintering aid.

And a binder, a plasticizer, a solvent, etc. were added to these powder materials (In addition, a sintering auxiliary agent selects and uses 1 type or multiple types from each powder), The ceramic slurry was produced.
Using this ceramic slurry, as shown in FIG. 2A, a plurality of ceramic green sheets 11 were produced by the doctor blade method.

<Production Process of Laminate: Third Process>
As shown in FIG. 2 (b), a plurality of (for example, three) ceramic green sheets 11 were laminated to produce a first laminate 13 to be the first ceramic layer 7.

Further, as shown in FIG. 2C, a plurality of (for example, two) ceramic green sheets 11 were laminated to produce a second laminate 15 to be the second ceramic layer 9.
That is, the thickness of the first laminate 13 (and thus the first ceramic layer 7) is larger than that of the second laminate 15 (and thus the second ceramic layer 9). The number of laminated ceramic green sheets 11 was increased. In addition, you may use not only a laminated body like the 1st, 2nd laminated bodies 13 and 15, but a ceramic green sheet from which thickness differs 1 sheet at a time.

Then, as shown in FIG. 2D, a conductive paste for the internal wiring layer was screen printed on one surface of the first laminate 13 to form a wiring pattern 17 for the internal wiring layer.
Next, as shown in FIG. 2E, the first laminate 13 and the second laminate 15 were laminated to produce a laminate 19 to be the ceramic wiring board 1. Specifically, the second stacked body 15 was stacked on the side of the first stacked body 13 on which the wiring pattern 17 was formed, so that the second stacked body 15 was stacked.

<Firing step: fourth step>
Next, the laminated body 19 on which the wiring pattern 17 was formed was degreased as is well known and then co-fired under predetermined firing conditions. In addition, as baking conditions, the conditions which bake for 0.5 to 2 hours in a temperature range of 1200-1300 degreeC, for example in reducing environment are employable. Thus, a ceramic wiring board 1 shown in FIG. 2 (f) was obtained.

[1-3. effect]
In the conductive paste of the present embodiment, when the particle size of the powder of W in the conductive paste is such that the D50 particle diameter is in the range of 0.7 μm to 0.9 μm and the conductive component is 100 parts by weight, The ratio of Cu in the component is 5 parts by weight to 70 parts by weight.

  Therefore, phenomena such as thickening due to gelation of the conductive paste are less likely to occur. That is, phenomena such as hardening of the conductive paste and formation of a film on the surface hardly occur. Therefore, since the state of the conductive paste is stable, fine wiring and the like can be easily formed by screen printing or the like even if a long time has passed since the production of the conductive paste.

In this embodiment, since the D50 particle size of the W powder is 0.7 μm or more, there is an advantage that there is little risk such as ignition of the powder, and the handling is easy.
In the present embodiment, since the ratio of Cu is 5 parts by weight or more, the electrical characteristics (for example, specific resistance) of the internal wiring layer 5 formed using the conductive paste are smaller than when the ratio of Cu is smaller than that. The characteristic of being small) is excellent.

In this embodiment, since the proportion of Cu having a low melting point is 70% by weight or less, there is an advantage that the shape retention of the wiring is high at the time of firing, and the Cu extrusion can be suppressed.
Further, in the method of manufacturing the ceramic wiring board of the present embodiment, the wiring pattern 17 is formed on the ceramic green sheet 11 (specifically, the first laminate 13) using the above-described conductive paste, and co-firing is performed. There is an effect that deformation such as warpage of the wiring board 1 can be suppressed. In particular, when the wirings are arranged asymmetrically on the ceramic wiring substrate 1, a remarkable effect can be obtained in suppressing the deformation.

The average grain size (grain size) of W in the internal wiring layer 5 of the ceramic wiring board 1 manufactured in this manner is, for example, in the range of 0.7 μm to 1.2 μm.
[2. Experimental example]
Next, Experimental Examples 1 and 2 performed to confirm the effects of the present disclosure will be described.

Experimental Example 1
Experimental Example 1 is to investigate the stability of the state of the conductive paste.
In this experimental example 1, samples of conductive pastes Nos. 1 to 6 shown in the following Table 1 were prepared as samples of examples of the scope of the present disclosure, and as samples of comparative examples outside the scope of the present disclosure. And samples of conductive pastes of Nos. 7 to 9 were produced.

Below, the preparation method of a sample is demonstrated.
First, as conductive materials, W powder of particle size (that is, D50 particle diameter) shown in Table 1 below and Cu powder of D50 particle diameter of 3.3 μm are prepared, and Cu powder and W powder are mixed in the ratio of Table 1 Mixed. Furthermore, when the total weight of Cu powder and W powder was 100 parts by weight, 1 part by weight of alumina powder having an average particle diameter of 150 nm or less was added to the conductive material in an external weight part.

The particle size of the powder such as W powder was measured by an air permeation method using Sub Sieve Sizer manufactured by Fisher Corporation.
Next, an ethyl cellulose resin and a terpineol solvent as varnish components were added to the mixed powder, and the mixture was kneaded by a three-roll mill to prepare a conductive paste of each sample.

そして、このように作製した各試料の導電性ペーストに対して、凝集（即ち部分的な塊の発生）やゲル化の有無を、８日間に渡り観察した。すなわち、導電性ペーストの状態の安定性を、外観により評価した。

Then, with respect to the conductive paste of each sample prepared in this manner, the presence or absence of aggregation (i.e., generation of partial lumps) or gelation was observed for 8 days. That is, the stability of the state of the conductive paste was evaluated by the appearance.

  In this evaluation, it was determined that there was a change in the conductive paste when aggregation or gelation was observed with the naked eye. The results are shown in Table 2 below.

この表２から明らかなように、実施例のNo.１〜６の試料では、８日を経過しても、導電性ペーストに変化が見られないので、好適であった。

As is clear from Table 2, the samples No. 1 to 6 of the example were suitable because no change was observed in the conductive paste even after 8 days.

On the other hand, in the samples of Nos. 7 to 9 of the comparative example, on the eighth day, the conductive paste changes, which is not preferable.
<Experimental Example 2>
Experimental example 2 investigates the generation | occurrence | production state of the curvature of a ceramic wiring board.

  In Experimental Example 2, samples of ceramic wiring boards No. 10 and 11 were prepared as samples of examples using a conductive paste within the scope of the present disclosure, and conductive pastes outside the scope of the present disclosure were used. As a sample of the comparative example, a sample of the ceramic wiring board of No. 12 was produced.

Below, the preparation method of a sample is demonstrated.
<Production of ceramic green sheet>
First, an Al ₂ O ₃ powder was prepared as a main raw material (a raw material to be a main component) of the ceramic substrate 3, and a powder of SiO ₂ , MgCO ₃ , BaCO ₃ or the like was prepared as a sintering aid. As the Al ₂ O ₃ powder, one having an average particle diameter of 0.5 μm was used.

  Furthermore, as a material for forming a sheet, a binder (for example, butyral-based binder), a plasticizer (for example, DOP: di-octyl phthalate), a solvent (for example, ethanol or ethylene) are prepared.

Then, it made of _Al 2 _{O 3} pots, the powder material with the powder of _Al 2 _{O 3} powder and the sintering aid were placed in 2500g weighed. Incidentally, Al ₂ O ₃ powder is used 90% by volume, the balance, a sintering aid was used to select one or more from each powder.

  Next, after a predetermined amount of coloring agent was charged into the pot, 300 g of butyral resin was charged. Furthermore, a solvent (ethanol or toluene) and a plasticizer (DOP) were added in an amount necessary to give an appropriate slurry viscosity and sheet strength, and pulverized and mixed for 20 hours to obtain a ceramic slurry.

Next, using this ceramic slurry, ceramic green sheets having a thickness of 0.1 mm and 0.05 mm were obtained by a doctor blade method.
<Preparation of samples for evaluation>
Then, as shown in FIG. 3, six 0.05 mm ceramic green sheets 35 were laminated on the 0.1 mm thick ceramic green sheet 31 so that the internal wiring pattern 33 with a thickness of 10 μm was sandwiched between the layers. . That is, laminated bodies 37 corresponding to the samples of Nos. 10 to 12 in which the internal wiring patterns 33 were disposed at six locations among the seven ceramic green sheets 31 and 35 in total were produced.

  Here, the internal wiring pattern 33 was formed using the Cu-based conductive paste prepared in the above-mentioned Experimental Example 1. In detail, in order to produce the ceramic wiring board of the sample of No. 10 of an Example, and the sample of No. 11, the electrically conductive paste of the sample of No. 4 of Experimental example 1 and No. 2 was used, respectively. Similarly, in order to produce the ceramic wiring board of the sample of No. 12 of the comparative example, the conductive paste of the sample of No. 7 of Experimental Example 1 was used.

Moreover, the outer side wiring patterns 39 and 41 were formed using the electrically conductive paste which has Mo as a main component on the both sides (upper and lower direction in FIG. 3) of the thickness direction of each laminated body 37. As shown in FIG.
Then, by sintering each of the laminates 37 obtained in this manner in a wetter atmosphere at 1200 ° C. to 1300 ° C., the ceramic wiring board of the sample of No. 10 to 12 which is a sample for evaluation, ie, the inside And the rectangular parallelepiped-shaped ceramic wiring board provided with wiring on the surface was obtained.

<Evaluation>
The shape of each sample was measured using a KEYENCE laser displacement meter LK-H020. Specifically, profiles were prepared in the diagonal direction of each sample, and the difference between the highest point and the lowest point was determined as the amount of warpage. The results are shown in Table 3 below.

  In addition, each sample was broken so as to include the internal wiring (that is, the internal wiring pattern after firing). Next, the fractured surface was polished, and observation with a secondary electron image was performed using a 3000 × scanning electron microscope (SEM).

  Specifically, for all the W particles in a predetermined range (for example, 20 μm square) of the image of the fracture surface of the internal wiring, the particle size is measured in the horizontal direction (arrow direction in the same figure) as shown in FIG. The diameter was calculated. The results are shown in Table 3 below.

表３から明らかなように、実施例のNo.１０、No.１１の試料では、Ｗ粒子の平均粒径が小さく、反り量が小さいので好適である。

As apparent from Table 3, in the samples of No. 10 and No. 11 of the example, the average particle diameter of W particles is small and the warpage amount is small, which is preferable.

On the other hand, in the sample of No. 12 of the comparative example, the average particle diameter of W particles is large and the amount of warpage is large, which is not preferable.
[3. Other Embodiments]
As mentioned above, although embodiment of this indication was described, this indication is not limited to the above-mentioned embodiment, It is possible in the range which does not deviate from the gist of this indication to carry out in various modes.

  (1) For example, as ceramic which comprises a ceramic substrate, various ceramics (for example, a zirconia, aluminum nitride, silicon nitride) other than an alumina can be employ | adopted, without being limited to the said embodiment.

(2) Various compositions can be adopted for the conductive paste and the internal wiring layer without departing from the scope of the present disclosure.
(3) Note that the function possessed by one component in the above embodiment may be shared by a plurality of components, or the function possessed by a plurality of components may be exhibited by one component. Further, part of the configuration of the above embodiment may be omitted. In addition, at least a part of the configuration of the above-described embodiment may be added to or replaced with the configuration of the other embodiments. In addition, all the aspects contained in the technical thought specified from the wording as described in a claim are an embodiment of this indication.

DESCRIPTION OF SYMBOLS 1 ... Ceramic wiring board 3 ... Ceramic board 5 ... Internal wiring layer 11, 31, 35 ... Ceramic green sheet 17 ... Wiring pattern 33 ... Internal wiring pattern 39, 41 ... Outer side wiring pattern

Claims (3)

In a conductive paste containing Cu powder and W powder as a conductive component,
The particle size of the W powder is such that the D50 particle size is in the range of 0.7 μm to 0.9 μm,
And, when the conductive component is 100 parts by weight, the ratio of Cu in the conductive component is 5 parts by weight to 70 parts by weight.
Conductive paste. Forming a wiring pattern on a ceramic green sheet using the conductive paste according to claim 1;
Co-firing the ceramic green sheet and the wiring pattern to produce a ceramic wiring substrate having a wiring on the ceramic substrate;
Have
Method of manufacturing a ceramic wiring board. The average particle size of the W in the wiring is in the range of 0.7 μm to 1.2 μm.
A method of manufacturing a ceramic wiring board according to claim 2.

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