WO2010106969A1

WO2010106969A1 - Charged powder for forming conductor pattern, method for producing same, and method for manufacturing multilayer ceramic electronic component using same

Info

Publication number: WO2010106969A1
Application number: PCT/JP2010/054181
Authority: WO
Inventors: 桜田清恭; 山崎力; 内田晋介; 丸山則彦
Original assignee: 株式会社村田製作所
Priority date: 2009-03-18
Filing date: 2010-03-12
Publication date: 2010-09-23

Abstract

Disclosed is a charged powder for forming a conductor pattern, which is used for forming a dense conductor layer having low resistance. Also disclosed are a method for producing the charged powder for forming a conductor pattern, and a method for manufacturing a multilayer ceramic electronic component using the charged powder for forming a conductor pattern. Specifically disclosed is a charged powder for forming a conductor pattern, which is used when a conductor pattern is printed on a print-receiving material. The charged powder for forming a conductor pattern is configured of resin particles (3) each of which is formed from a first thermoplastic resin (3a) in which conductive metal particles (1) are dispersed, and a coating resin layer (4) which covers each resin particle (3) and is formed from a second thermoplastic resin (4a) that has a softening point lower than that of the first thermoplastic resin (3a) constituting the resin particles. The difference between the softening point of the first thermoplastic resin and the softening point of the second thermoplastic resin is not less than 20˚C. Ultrafine thermoplastic resin particles having a diameter of 50-500 nm are used for the coating resin layer. A silica coating layer (5) which is configured of silica particles is provided on the surface of the coating resin layer. Each resin particle is formed to contain ceramic particles (2) or glass particles.

Description

Conductive powder for forming conductive pattern, method for producing the same, and method for producing multilayer ceramic electronic component using the same

The present invention relates to a conductive pattern forming charged powder used when a conductor pattern is printed on a substrate by electrophotography, a method for producing the same, and a multilayer ceramic electronic component using the conductive pattern forming charged powder. It relates to a manufacturing method.

In multilayer ceramic electronic parts such as ceramic multilayer substrates, as a method of forming internal conductors disposed between ceramic layers and external conductors disposed on the outer surface, conductive powder for forming conductive patterns is printed by electrophotography. Then, there is a method of baking the chargeable powder and the ceramic layer at the same time.

This electrophotographic method is a method in which a pattern due to static electricity is drawn on a substrate to be printed, and a charged toner is attached thereto and fixed by heating. There is a demand for improvement in chargeability that affects the accuracy of the toner and relaxation of the fusion (pressing and heating) conditions during fixing.

In addition, when the chargeable toner is used for forming a conductor pattern in a multilayer ceramic electronic component, patterning accuracy deteriorates in processes such as a lamination process performed after fixing, a thermocompression bonding process of the laminated body, and a heat cutting process. It is important that the charged toner itself is not destroyed so as not to cause delamination.

In order to satisfy these conditions, as shown in FIG. 3, the surface of resin particles 53 made of a metal powder (conductive particles) 51 and a thermosetting resin (epoxy resin) 53a in which a charge control agent 52 is dispersed. There has been proposed a chargeable toner 60 in which is coated with a resin coating layer 54 made of a thermoplastic resin (Patent Document 1).
That is, in the chargeable toner 60, the inner resin particles 53 are made of a thermosetting resin for the purpose of improving the strength, and the outer coating resin layer 54 is thermoplastic to improve the fixing property. It is made of resin.

In the case of this chargeable toner, the thermoplastic resin is used for the outer covering resin layer 54 as described above, so that the pattern fixing property is excellent and the resin constituting the inner resin particles 53 is thermoset. Since the conductive resin 53a is used, it has sufficient strength even during heat-compression bonding and heat-cutting, and is not destroyed, so that a highly accurate pattern can be formed.

However, since a thermosetting resin is used for the resin particles, even if the resin component does not soften in the firing step and eventually burns and scatters, The conductive particles contained in the conductive pattern cannot freely move, and in the conductor pattern, the conductive particles are sintered while being separated from each other, so that a dense conductive layer cannot be formed. There is a point.

Japanese Patent Laid-Open No. 4-237064

The present invention solves the above-mentioned problems, and uses a conductive pattern-forming charged powder capable of forming a dense and low-resistance conductor layer, a method for producing the same, and the conductive pattern-forming charged powder. An object of the present invention is to provide a method for manufacturing a multilayer ceramic electronic component capable of manufacturing a multilayer ceramic electronic component having good characteristics.

The charged powder for forming a conductor pattern of the present invention is
A conductive powder for forming a conductor pattern used when printing a conductor pattern on a substrate,
Resin particles made of a first thermoplastic resin in which conductive metal particles are dispersed;
And a coating resin layer made of a second thermoplastic resin having a softening point lower than that of the first thermoplastic resin constituting the resin particles.

In the conductive powder for forming a conductor pattern of the present invention, it is desirable that the difference between the softening point of the first thermoplastic resin and the softening point of the second thermoplastic resin is 20 ° C. or more.

The coating resin layer is preferably formed using ultrafine thermoplastic resin particles having a diameter of 50 nm to 500 nm.

Further, it is desirable that the coating resin layer has a silica coating layer made of silica particles on the surface thereof.

Also, the conductive powder for forming a conductor pattern of the present invention is desirably used for printing a conductor pattern on a ceramic green sheet by electrophotography.

Further, in the case where it is used to print a conductor pattern on a ceramic substrate, the resin particles contain ceramic particles containing the same component as at least one component of the ceramic constituting the ceramic substrate, Also,
In the case of being used for printing a conductor pattern on a glass substrate, the resin particles contain glass particles containing the same component as at least one component of the glass constituting the glass substrate. Is desirable.

Further, the method for producing a conductive powder for forming a conductor pattern of the present invention,
A method for producing a conductive powder for forming a conductor pattern used when printing a conductor pattern on a substrate by electrophotography,
Dispersing the conductive metal particles in the first thermoplastic resin;
Pulverizing the first thermoplastic resin to form resin particles in which the conductive metal particles are dispersed in the first thermoplastic resin; and
The resin particles are mixed with thermoplastic resin fine particles made of a second thermoplastic resin having a softening point lower than that of the first thermoplastic resin. And a step of forming a coating resin layer made of a thermoplastic resin.

It is desirable to provide a step of forming a silica coating layer by attaching silica particles to the surface of the coating resin layer.

In addition, the method for manufacturing the multilayer ceramic electronic component of the present invention includes:
Printing the conductive powder for forming a conductor pattern according to any one of claims 1 to 5 on a ceramic green sheet by electrophotography so as to form a predetermined pattern;
The conductive powder for forming a conductive pattern printed on the ceramic green sheet is higher than the softening point of the second thermoplastic resin constituting the coating resin layer, and the first thermoplastic resin constituting the resin particles Heating at a temperature lower than the softening point of the layer to fix the conductive pattern forming charged powder on the ceramic green sheet; and
Forming a mother laminate by stacking and pressing a plurality of ceramic green sheets including the ceramic green sheet; and
Cutting the mother laminate while heating at a temperature lower than the softening point of the second thermoplastic resin layer constituting the coating resin layer, and dividing the mother laminate into individual laminates;
A degreasing step of removing organic components including the thermoplastic resin from the laminate;
And a firing step in which the degreased laminate is fired to form a sintered body.

The conductive powder for forming a conductive pattern of the present invention is a second thermoplastic resin having a lower softening point than that of the first thermoplastic resin, in which conductive metal particles are dispersed and the first thermoplastic resin is dispersed. Since a coating (printing pattern) formed using the conductive pattern-forming chargeable powder is heated and fixed, the first thermoplastic resin constituting the resin particles is coated with the coating resin layer made of Although the resin is not softened, the second thermoplastic resin constituting the coating resin layer is heated to such a temperature that it softens, thereby softening the second thermoplastic resin at a relatively low temperature and improving the fixability. Can be made.

Also, after laminating ceramic green sheets to which conductor patterns are fixed to form a laminate, this is heated to soften the binder component of the laminate (binder component contained in the ceramic green sheet) before cutting In this case, the fixing property of the conductor pattern is prevented from being deteriorated by heating to a temperature lower than the softening point of the first and second thermoplastic resins constituting the resin particles and the coating resin layer. Moreover, it is possible to suppress or prevent the occurrence of delamination caused by the resin particles being destroyed due to insufficient strength during cutting.

Furthermore, since a thermoplastic resin is used as the resin constituting the resin particles, the resin particles are softened when the binder is removed, and the conductive particles contained therein are movable, so that the conductor layer is dense and has low resistance. Can be formed.

In addition, since the resin particles are coated with the coating resin layer, the exposure of the conductive metal particles can be suppressed and the charging characteristics can be ensured. In addition, preventing the exposure of the conductive metal particles in this way is a matter that is a basic condition for imparting electric resistance and is an important requirement.

In the charged powder for forming a conductor pattern of the present invention, various known charge control agents can be blended. Examples of the charge control agent suitable for use in the conductive powder for forming a conductor pattern of the present invention include azo-containing metal compounds, salicylic acid compounds, azine compounds, and quaternary ammonium salts.

Further, in the conductive powder for forming a conductor pattern of the present invention, by setting the difference between the softening point of the first thermoplastic resin and the softening point of the second thermoplastic resin to 20 ° C. or more, in the fixing step, While the coated resin layer softens, it is possible to reliably realize a state in which the resin particles inside do not soften, and in the subsequent heat treatment process such as degreasing, the resin particles are quickly softened at a relatively low temperature. Thus, the conductive metal particles can be made to flow at an early timing, and the present invention can be more effectively realized.
In the present invention, the 5 mm flow start temperature by the flow tester apparatus was defined as the “softening point” of the thermoplastic resin.

In addition, when forming the coating resin layer, when the thermoplastic resin ultrafine particles having a diameter of 50 nm to 500 nm are used, the thermoplastic resin ultrafine particles collide with the resin particles by mechanical mixing, and the impact at that time It is possible to efficiently form a coated resin layer by using a method (mechanical coating method) in which the thermoplastic resin ultrafine particles are deformed by force and adhered to the surface of the resin particles so that the thermoplastic resin ultrafine particles adhere to the surface. become.
In the case of the above-mentioned mechanical coating method, it is desirable that the resin particles have a diameter 5 to 10 times that of the ultrafine thermoplastic resin particles or more.

Also, by providing a silica coating layer made of silica particles on the surface of the coating resin layer, it becomes possible to impart sufficient chargeability. From the viewpoint of improving the chargeability, it is preferable to use hydrophobized silica fine particles.

In addition, when applying the silica particles by a mechanical coating method, if the bite into the coating resin layer and the exposure amount is too small, the effect of providing the silica coating layer will be reduced. It is desirable to give the coating resin layer an appropriate hardness so that the silica particles do not bite into the coating resin layer too much.
Furthermore, by covering the thermoplastic resin with the silica fine particle layer, it is possible to ensure the fluidity of the conductive pattern forming chargeable powder.

The charged powder for forming a conductor pattern of the present invention can be suitably used when a conductor pattern is printed on a ceramic green sheet by electrophotography.

Further, in the case where the conductive powder for forming a conductor pattern of the present invention is used for printing a conductor pattern on a ceramic substrate, at least one component of the ceramic constituting the ceramic substrate is added to the resin particles. In the case where ceramic particles containing the same component are contained and the conductive powder for forming a conductor pattern of the present invention is used for printing a conductor pattern on a glass substrate, the glass substrate is added to the resin particles. By including glass particles containing the same component as at least one component of the glass to be formed, the affinity of the conductive pattern to be formed to the ceramic substrate or the glass substrate and the adhesion can be improved and an anchor effect can be obtained. Thus, the present invention can be made more effective.
For example, in the case where a conductor pattern is formed on a ceramic green sheet mainly composed of a BaO—Al ₂ O ₃ —SiO ₂ based ceramic material, a conductive metal is used as the resin particles constituting the conductive powder for forming the conductor pattern. By adding Al ₂ O ₃ particles as ceramic particles together with powder and the like, it is possible to form a conductor pattern having a large adhering force to the ceramic substrate.

In the method for producing a conductive powder for forming a conductor pattern according to the present invention, the conductive metal particles are dispersed in the first thermoplastic resin, and then the first thermoplastic resin is pulverized to obtain the conductive metal particles. The resin particles dispersed in the first thermoplastic resin are formed, and the resin particles are mixed with the thermoplastic resin fine particles made of the second thermoplastic resin having a softening point lower than that of the first thermoplastic resin. Since the coating resin layer made of the second thermoplastic resin is formed on the surface of the resin particles by the coating method, a conductive powder for forming a conductor pattern capable of forming a dense and low resistance conductor layer That is, it becomes possible to reliably manufacture the conductive pattern forming powder having the requirements of the present invention.

In addition, when the silica coating layer is formed by attaching silica particles to the surface of the coating resin layer, the conductive pattern forming charged powder having sufficient chargeability and excellent fluidity is ensured. To be able to get to.

Also, the method for producing a multilayer ceramic electronic component of the present invention includes a second thermoplastic resin that forms a coating resin layer by printing the conductive pattern forming charged powder of the present invention on a ceramic green sheet by electrophotography. Heating is performed at a temperature higher than the softening point of the first thermoplastic resin layer constituting the resin particles and lower than the softening point of the first thermoplastic resin layer to fix the conductive pattern forming charged powder. Sheets are laminated and pressure-bonded to form a mother laminate, cut while heating at a temperature lower than the softening point of the second thermoplastic resin layer, and divided into individual laminates, followed by degreasing and firing. Therefore, it is possible to efficiently manufacture a multilayer ceramic electronic component having a good characteristic with a dense and low resistance conductor pattern, such as a ceramic multilayer substrate. It made.

It is sectional drawing which shows the structure of the conductive powder for conductor pattern formation concerning one Example (Example 1) of this invention. It is sectional drawing which shows typically the ceramic multilayer substrate manufactured using the ceramic green sheet which formed the conductive pattern by printing the conductive powder for conductor pattern formation of this invention. It is sectional drawing which shows the structure of the conventional chargeable toner.

Hereinafter, the features of the present invention will be described in more detail with reference to examples of the present invention.

In this embodiment, the first conductive pattern forming charged powder of the present invention will be described as an example.

FIG. 1 is a diagram showing a configuration of a conductive pattern forming powder according to an embodiment of the present invention.
The conductive powder 10 for forming a conductor pattern of this embodiment is a conductive powder for forming a conductor pattern used when printing a conductor pattern by electrophotography.

The conductive pattern forming chargeable powder 10 includes copper particles (conductive metal particles) 1 having an average particle size of 1 μm, ceramic particles (alumina particles in this embodiment) 2 having a particle size of 0.5 μm, and The charge control agent (in this embodiment, an azo-containing metal compound) 6 is dispersed on the surface of the resin particle 3 in which the softening point is dispersed in a polyester resin 3a having a softening point of about 180 ° C. (first thermoplastic resin in the present invention). A coating resin layer 4 comprising a second thermoplastic resin (acrylic resin having a softening point of 120 ° C.) 4a having a softening point lower than that of the first thermoplastic resin (polyester resin having a softening point of about 180 ° C.) 3a; And a silica coating layer 5 made of silica particles (silica ultrafine particles) 5 a disposed so as to cover the coating resin layer 4.

The conductive pattern forming chargeable powder 10 includes a coating resin layer 4 made of a second thermoplastic resin 4a having a softening point lower than that of the first thermoplastic resin 3a. In the process of heating and fixing the conductor pattern (printing pattern) formed using the conductive pattern forming chargeable powder 10, the first thermoplastic resin 3a is not softened. By heating the second thermoplastic resin 4a to a temperature at which it softens, the second thermoplastic resin 4a can be softened at a relatively low temperature and the fixability can be improved.

Also, after laminating ceramic green sheets with a conductive pattern (printing pattern) fixed thereon to form a laminate, this is heated to soften the binder component of the laminate (binder component in the ceramic green sheet) before cutting. In the case of performing the above, the conductor pattern is fixed by heating and cutting to a temperature lower than the softening point of the first and second

thermoplastic resins

3a and 4a constituting the resin particles 3 and the coating resin layer 4. It is possible to prevent the deterioration of the properties and to suppress the occurrence of delamination caused by the resin particles 3 being destroyed due to insufficient strength at the time of cutting.

Furthermore, although the first thermoplastic resin constituting the resin particle 3 has a higher softening point than the second thermoplastic resin, it is the thermoplastic resin 3a, so that it softens at the time of binder removal and is included inside. Since the conductive metal particles 1 are movable, a dense and low-resistance conductive layer can be formed.

In addition, since the resin particles 3 are covered with the coating resin layer 4, the conductive metal particles 1 can be prevented from being exposed, and charging characteristics can be imparted. On the premise of this, since the charge control agent 6 is further blended and the silica coating layer 5 is disposed so as to cover the coating resin layer 4, desired charging characteristics can be provided. .

In the conductive pattern forming chargeable powder 10 of this embodiment, the resin particles 3 contain alumina particles 2 that are one of ceramic materials constituting the ceramic green sheet that is the printed material. It is possible to form a conductor layer having a large affinity and adhesion strength.

Next, a method for producing the conductive pattern forming powder will be described.
(1) Copper particles having an average particle diameter of 1 μm, ceramic particles having an average particle diameter of 0.5 μm (in this example, alumina particles), and a polyester resin having a softening point of about 180 ° C. The first thermoplastic resin in the present invention) and the charge control agent (azo-containing metal compound in this example) are weighed so that the ratio of the inorganic material to the organic material is 9: 1 by weight, Mixed.
In addition to the azo-containing metal compound, a salicylic acid compound, an azine compound, a quaternary ammonium salt, or the like can be used as the charge control agent.

(2) Then, this mixture was put into a kneader and kneaded at 170 ° C. for 30 minutes.

(3) Next, the obtained kneaded material was finely pulverized using a jet mill, whereby conductive metal particles, alumina particles, and a charge control agent were dispersed in the polyester resin (first thermoplastic resin). Resin particles were obtained.

(4) Then, the resin particles are mixed with acrylic resin ultrafine particles having a diameter of about 100 nm that are softened at a temperature (120 ° C.) lower than that of the polyester resin (first thermoplastic resin), and the mixture is mixed with Mitsui. By putting it into a mine MP mixer and stirring for 5 minutes at a rotational speed of 5000 rpm, as shown in FIG. 1, in the polyester resin (first thermoplastic resin) 3a, conductive metal particles 1 and alumina particles. 2. The coated particles 7 having the resin particles 3 in which the charge control agent 6 was dispersed and having the surface coated with the coated resin layer 4 made of an acrylic resin (second thermoplastic resin) 4a were obtained.

(5) Then, ultrafine silica particles (silica particles) 5 a having a diameter of 7 nm were adhered to the surface of the coated resin layer 4 by further mixing the coated particles 7.
Part of the silica ultrafine particles 5a bites into the coating resin layer 4 during mixing, so that the silica coating layer 5 is formed on the surface of the coating resin layer 4.
As the silica particles, it is desirable to use silica ultrafine particles as described above. In that case, it is desirable to use particles having a diameter of 5 nm to 20 nm.

Thereby, as shown in FIG. 1, the surface of the resin particle 3 made of the first thermoplastic resin 3a is covered with the covering resin layer 4 made of the acrylic resin (second thermoplastic resin) 4a. A conductive pattern forming chargeable powder 10 having a structure in which the resin layer 4 is coated with the silica coating layer 5 is obtained.

In the process of producing the conductive pattern forming chargeable powder 10, the charging characteristics were measured. The charging characteristics of the resin particles 3 before forming the coating resin layer 4 were −4.8 μC / g. On the other hand, after the formation of the coating resin layer 4, it was −12.8 μC / g, and it was confirmed that the charge amount of the negative charge was greatly improved.

This is because the exposed surface of the conductive metal particle 1 exposed on the surface of the resin particle 3 is coated with the coating resin layer 4 made of an acrylic resin as an insulator, and the negative charge amount is improved because the insulation is improved. Conceivable.

[Characteristic evaluation]
As the first thermoplastic resin constituting the resin particles and the second thermoplastic resin constituting the coating resin layer, those having various softening points as shown in Table 1 were prepared, and the same conditions as in the examples Thus, a chargeable powder for forming a conductor pattern having a structure as shown in FIG. 1 was produced.
And about these chargeable powders for conductor pattern formation, fluidity | liquidity, fixing property, and charging property were investigated.

For comparison, as the first resin constituting the resin particles, a thermosetting polyester resin (polyester thermosetting resin) is used instead of thermoplastic, and the second heat constituting the coating resin layer is used. As the plastic resin, a conductive powder for forming a conductive pattern was prepared using the same ultrafine particles of an acrylic resin as a thermoplastic resin as in the above-described example, and the characteristics thereof were evaluated.
The results are shown in Table 1.

Moreover, the laminated body (ceramic multilayer board | substrate) was produced in the following procedures using the conductive powder for each conductor pattern formation shown in Table 1.
(1) Each conductive pattern forming chargeable powder shown in Table 1 has a predetermined pattern on a ceramic green sheet mainly composed of a BaO—Al ₂ O ₃ —SiO ₂ ceramic material by electrophotography. To print.

(2) The first thermoplastic resin layer constituting the resin particles, wherein the conductive pattern forming charged powder printed on the ceramic green sheet is higher than the softening point of the second thermoplastic resin constituting the coating resin layer. The conductive pattern forming charged powder is fixed on the ceramic green sheet by heating at a temperature lower than the softening point.

(3) A mother laminated body is formed by stacking and pressing a plurality of ceramic green sheets including ceramic green sheets to which the conductive pattern forming chargeable powder is fixed.
Here, as a ceramic green sheet, a via hole through hole for interlayer connection is formed as necessary, and a via hole conductor is disposed there, and a predetermined conductor pattern is used as a via hole conductor. Interlayer connection was made through this.

(4) Then, the mother laminate is cut while being heated to a temperature lower than the softening point of the second thermoplastic resin layer constituting the coating resin layer, and divided into individual laminates.

(5) Next, the laminate is heat-treated at a predetermined temperature to remove organic components including the thermoplastic resin from the laminate.

(6) Thereafter, the laminate from which the organic component including the thermoplastic resin has been removed (defatted) is fired.
Thereby, for example, as schematically shown in FIG. 2, a ceramic multilayer substrate having a structure in which a ceramic layer 21 that is an insulating layer and a conductor pattern 22 are laminated and a predetermined conductor pattern 22 is connected by a via-hole conductor 23. (Laminate) 20 is obtained.

And about this ceramic multilayer substrate (laminated body), the presence or absence of the structural defect and the porosity of the conductor pattern (conductor layer) were investigated and evaluated (number of samples: 100).
The results are also shown in Table 1.

In addition, each characteristic of the fluidity | liquidity regarding the chargeable powder for conductor pattern formation of Table 1, a fixing property, and charging property was evaluated with the following method.
<Fluidity>
3 g of charged powder for conductor pattern formation is put into a 50 mL graduated cylinder, and the conductor pattern is formed from the inner bottom surface of the graduated cylinder when the graduated cylinder is tilted sideways with respect to the initial filling height (axial distance). The ratio of the axial distance of the graduated cylinder to the position where the tip of the chargeable powder reached was examined, and the fluidity was evaluated from this value. In addition, the relationship between the evaluation result of fluidity by ◎, ○, Δ, × and the value of the above ratio is as follows.
◎: 2.0 or more ○: 1.5 to less than 2.0 △: Less than 1.2 to 1.5 ×: Less than 1.2

<Fixability>
The printed conductive pattern-forming charged powder is heated at a temperature higher than the softening point of the second thermoplastic resin constituting the coating resin layer and lower than the softening point of the first thermoplastic resin layer constituting the resin particles. After fixing on the ceramic green sheet, the fixability was evaluated by examining the extent to which the conductive pattern forming charged powder (printed film) was transferred to the finger by rubbing with a finger. In addition, evaluation by ◎, ○, Δ, × of fixability is based on the following criteria.
A: The printed film cannot be removed even when rubbed with a finger after fixing.
◯: When rubbing with a finger after fixing, the conductive pattern forming charged powder adheres to the finger even though there is no pattern omission.
Δ: Conductive powder for forming a conductor pattern adheres to a finger when rubbed after fixing, and a part of the pattern is missing. ×: Charged powder for forming a conductor pattern adheres to a finger when rubbed after fixing, and the entire pattern is missing.

<Chargeability>
The charge amount of the chargeable powder for forming a conductor pattern was examined with a blow-off charge amount measuring device, and the chargeability was evaluated. In addition, the evaluation based on ◎, ○, Δ, and × of the charging property is based on the following criteria.
A: -10 μC / g or more B: −7 to less than −10 μC / g Δ: −6 to less than −7 μC / g ×: less than −6 μC / g Also, each of the structural defects and porosity of the laminate shown in Table 1 The characteristics were evaluated by the following method.

<Structural defects>
Evaluation was made by observing the cross section of the fired laminate with a metallographic microscope. The evaluation of structural defects by ◎, ○, Δ, × is based on the following criteria.
(Double-circle): Layer peeling is not recognized at all.
○: Generation of layer peeling was observed in 1 to 20% of all samples.
Δ: Generation of layer peeling was observed in 20 to 30% of all samples.
X: Generation of layer peeling was observed in 30% or more of all samples.

<Porosity>
Evaluation was made by observing the cross section of the fired laminate with a metal microscope and examining the occurrence of voids on the conductor layer (electrode). In addition, the evaluation by the porosity of ◎, ○, Δ, × is based on the following criteria.
(Double-circle): A void is not recognized by an electrode.
○: Generation of voids was observed in 1 to 20% of all samples.
Δ: Generation of voids was observed in 20 to 30% of all samples.
X: Generation of voids was observed in 30% or more of all samples.

As shown in Table 1, the conductive pattern-forming chargeable powders according to the examples of the present invention with sample numbers 1 to 13 have practical characteristics (fluidity, fixability, and chargeability characteristics). It was confirmed.

In addition, a laminate (ceramic multilayer substrate) produced by laminating ceramic green sheets having a conductor pattern formed using the conductive powder for forming a conductor pattern of the present invention is also practical with regard to structural defects and porosity. It was confirmed that

On the other hand, as in the case of the comparative example, polyester-based thermosetting is used as the first resin that constitutes the resin particles, and acrylic resin that is a thermoplastic resin as the second thermoplastic resin that constitutes the coating resin layer. When the ultrafine particles of the above were used, the flowability, fixability, and chargeability of the conductive pattern forming powder were good, but the conductor pattern formed using the conductive pattern forming powder of this comparative example The laminated body (ceramic multilayer substrate) produced by laminating the ceramic green sheets provided did not cause structural defects such as delamination, but the porosity of the conductor layer (electrode) increased, and the conductor pattern formation of the present invention It was confirmed that a dense and low-resistance conductor layer could not be obtained as in the case of using the chargeable powder.

In the above embodiment, a case where a polyester resin is used as the first thermoplastic resin constituting the resin particles and an acrylic resin ultrafine particle is used as the second thermoplastic resin constituting the coating resin layer is described. However, various resins can be used as long as the second thermoplastic resin satisfies the requirement that the softening point is lower than that of the first thermoplastic resin.

For example, a polyester resin having a different softening point (the second thermoplastic resin has a lower softening point) is used for both the first thermoplastic resin and the second thermoplastic resin, and both are softened. It is also possible to use acrylic resins having different points (the second thermoplastic resin has a lower softening point).

Further, a resin other than the polyester resin and the acrylic resin is used in combination with the polyester resin and the acrylic resin, or a resin other than the polyester resin and the acrylic resin is used for both the first thermoplastic resin and the second thermoplastic resin. It is also possible to do.
Moreover, in the said Example, although the silica coating layer was formed on the surface of the coating resin layer, it can also be set as the structure which does not form a silica coating layer on the surface of a coating resin layer depending on the case.

Further, in the above-described embodiment, alumina particles are contained in the resin particles as ceramic particles. However, depending on the constituent material of the ceramic green sheet on which the conductive pattern forming chargeable powder is printed, the ceramic green sheet ( You may make it contain the other kind of ceramic particle containing the same component as the at least 1 component of the ceramic which comprises a ceramic substrate.
Further, in some cases, it is possible not to contain the ceramic particles as contained in the above examples.

Further, in the above embodiment, alumina particles are contained in the resin particles as ceramic particles. For example, in the case of using a green sheet mainly composed of glass, which is a glass substrate, the resin particles are ceramic. It is also possible to make it contain glass particles instead of particles.

The present invention is not limited to the above-described embodiment in other points as well, and the types and blending ratios of the components constituting the conductive pattern-forming charged powder, the types and properties of the printed material, and the conductive pattern of the present invention. Various types of applications and modifications can be made within the scope of the invention with respect to the types of multilayer ceramic electronic parts manufactured using the chargeable powder for forming.

1 Conductive metal particles 2 Alumina particles (ceramic particles)
3a Polyester resin (first thermoplastic resin)
3 Resin particles 4a Acrylic resin (second thermoplastic resin)
4 Coating resin layer 5a Silica particles (silica ultrafine particles)
DESCRIPTION OF SYMBOLS 5 Silica coating layer 6 Charge control agent 7 Coated particle 10 Chargeable powder for conductor pattern formation 20 Ceramic multilayer substrate (laminated body)
21 Ceramic layer 22 Conductor pattern 23 Via hole conductor

Claims

A conductive powder for forming a conductor pattern used when printing a conductor pattern on a substrate,
Resin particles made of a first thermoplastic resin in which conductive metal particles are dispersed;
And a coating resin layer made of a second thermoplastic resin having a softening point lower than that of the first thermoplastic resin constituting the resin particles, which covers the resin particles. Charged powder.
The charged powder for forming a conductor pattern according to claim 1, wherein the difference between the softening point of the first thermoplastic resin and the softening point of the second thermoplastic resin is 20 ° C or more.
3. The charged powder for forming a conductor pattern according to claim 1, wherein the coating resin layer is formed using ultrafine thermoplastic resin particles having a diameter of 50 nm to 500 nm.
The conductive powder for forming a conductor pattern according to any one of claims 1 to 3, wherein the coating resin layer has a silica coating layer made of silica particles on the surface thereof.
The conductive powder for forming a conductor pattern according to any one of claims 1 to 4, which is used for printing a conductor pattern on a ceramic green sheet by electrophotography.
In the case of being used for printing a conductor pattern on a ceramic substrate, the resin particles contain ceramic particles containing the same component as at least one component of the ceramic constituting the ceramic substrate, and
In the case of being used for printing a conductor pattern on a glass substrate, the resin particles contain glass particles containing the same component as at least one component of the glass constituting the glass substrate. The charged powder for forming a conductor pattern according to any one of claims 1 to 5.
A method for producing a conductive powder for forming a conductor pattern used when printing a conductor pattern on a substrate by electrophotography,
Dispersing the conductive metal particles in the first thermoplastic resin;
Crushing the first thermoplastic resin to form resin particles in which the conductive metal particles are dispersed in the first thermoplastic resin;
The resin particles and thermoplastic resin fine particles made of a second thermoplastic resin having a softening point lower than that of the first thermoplastic resin are mixed, and a second coating is made on the surface of the resin particles by a mechanical coating method. Forming a coating resin layer made of a thermoplastic resin. A method for producing a conductive powder for forming a conductor pattern.
The method for producing a conductive powder for forming a conductor pattern according to claim 7, further comprising the step of forming a silica coating layer by attaching silica particles to the surface of the coating resin layer.
Printing the conductive powder for forming a conductor pattern according to any one of claims 1 to 6 so as to form a predetermined pattern on a ceramic green sheet by electrophotography;
The conductive powder for forming a conductive pattern printed on the ceramic green sheet is higher than the softening point of the second thermoplastic resin constituting the coating resin layer, and the first thermoplastic resin constituting the resin particles Heating at a temperature lower than the softening point of the layer to fix the conductive pattern forming charged powder on the ceramic green sheet; and
Forming a mother laminate by stacking and pressing a plurality of ceramic green sheets including the ceramic green sheet; and
Cutting the mother laminate while heating at a temperature lower than the softening point of the second thermoplastic resin layer constituting the coating resin layer, and dividing the mother laminate into individual laminates;
A degreasing step of removing organic components including the thermoplastic resin from the laminate;
And a firing step in which the degreased laminate is fired to form a sintered body.