JP4134372B2 - Chargeable powder for circuit formation, circuit pattern forming method using the same, and multilayer wiring board formed thereby - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a circuit pattern forming method using a conductive powder for forming a circuit comprising a conductive metal powder, a pressure deformable resin, and a charge control agent, and a multilayer wiring board formed thereby .
[0002]
[Prior art]
A circuit pattern forming method for forming a charged powder for circuit formation as a desired circuit pattern on a dielectric layer using electrostatic force, as in normal electrophotography, and a circuit used in this circuit pattern forming method A forming chargeable powder is proposed in JP-A-4-236484. FIG. 8 shows a configuration diagram of an electrophotographic system used when forming a circuit pattern on a ceramic green sheet. The circuit pattern is formed on the ceramic green sheet by a charging process in which the surface of the photoconductor 72 is charged by the corona charger 71, and the surface of the photoconductor 72 rotating in the direction of arrow A is irradiated with a laser beam 73 to form a desired latent image. An exposure process for forming an image pattern (not shown), a developing process for electrostatically adsorbing the charged powder 75 for circuit formation to the latent image pattern on the surface of the photoreceptor 72 by the supply means 74, and transferring from the back surface of the ceramic green sheet 76 A transfer step of applying a charge having a polarity opposite to that of the circuit forming chargeable powder 75 to the ceramic green sheet 76 by the device 77 and transferring the circuit forming chargeable powder 75 developed on the latent image pattern onto the ceramic green sheet 76. The charged powder 75 for circuit formation transferred onto the ceramic green sheet 76 by the irradiation of the flash lamp 78 is fixed, and the Constituted by a fixing step of forming a circuit pattern (not shown) on Mick green sheet 76.
[0003]
FIG. 9 shows a cross-sectional view of a conventional chargeable powder for circuit formation. The circuit-forming chargeable powder 75 has a structure in which the conductive metal powder 81 and the charge control agent 82 are uniformly dispersed in the heat-meltable resin 83, and the average particle diameter thereof is 10 to 15 μm.
[0004]
[Problems to be solved by the invention]
However, in the conventional circuit pattern forming method, since the chargeable powder for circuit formation to be used contains a heat-meltable resin, it is transferred onto the ceramic green sheet by melting the heat-meltable resin by applying heat. Further, a fixing process for fixing the circuit forming chargeable powder and forming a circuit pattern on the ceramic green sheet is required. In this fixing process, heat is applied not only to the circuit forming chargeable powder but also to the ceramic green sheet forming the circuit pattern. This heat shrinks the ceramic green sheet, and the dimensions of the ceramic green sheet are designed. There was a problem of deviating from the value.
[0005]
The present invention has been made to solve such problems, and a circuit pattern forming method capable of forming a circuit pattern on a ceramic green sheet without applying heat to the ceramic green sheet. An object of the present invention is to provide a multilayer wiring board formed by the above.
[0008]
[Means for Solving the Problems]
The circuit pattern forming method of the present invention comprises a charging step for charging the entire surface of the photoreceptor, an exposure step for forming an electrostatic latent image pattern on the photoreceptor , a conductive metal powder on the latent image pattern , A developing process for adhering a circuit-forming chargeable powder comprising a pressure-deformable resin and a charge control agent by electrostatic force, and a transfer for transferring the circuit-forming chargeable powder on the latent image pattern onto the ceramic green sheet. The ceramic green sheet without heating at a temperature at which the ceramic green sheet contracts by pressing the circuit-forming charged powder on the ceramic green sheet from the front and back sides of the ceramic green sheet. Using the electrophotographic method including a fixing step of fixing the charged powder for circuit formation transferred onto the ceramic powder. And forming a circuit pattern on Nshito.
[0009]
In addition, a charging process for charging the entire surface of the photoconductor, an exposure process for forming an electrostatic latent image pattern on the photoconductor, a conductive metal powder, a pressure-deformable resin, and a charge on the latent image pattern A development step of attaching a circuit forming chargeable powder composed of a control agent by electrostatic force; and the ceramic green sheet overlaid on the circuit formation chargeable powder on the latent image pattern, and from the back side of the ceramic green sheet By pressing the circuit forming chargeable powder on the latent image pattern, the circuit forming chargeable powder is transferred onto the ceramic green sheet without heating at a temperature at which the ceramic green sheet contracts. A circuit pattern is formed on the ceramic green sheet by using an electrophotographic method including a transfer fixing step for fixing.
[0010]
The multilayer wiring board of the present invention is characterized in that the ceramic green sheets on which the circuit pattern is printed are laminated and fired by the circuit pattern forming method described above.
[0011]
According to the circuit pattern forming method of the present invention, since the pressure- forming resin is included in the circuit-forming chargeable powder, when the circuit-forming chargeable powder is pressed from the back surface or the front and back surfaces of the ceramic green sheet. The pressure-deformable resin plays a role of transferring or fixing the charged powder for circuit formation onto the ceramic green sheet.
[0012]
The fixing process for fixing the circuit forming charged powder transferred onto the ceramic green sheet is performed by pressing the circuit forming charged powder on the ceramic green sheet. It is not necessary to apply heat that causes the ceramic green sheet to shrink . Therefore, shrinkage of the ceramic green sheet can be prevented.
[0013]
According to the multilayer wiring board of the present invention, a circuit pattern is printed on the ceramic green sheet by electrophotography using a circuit pattern forming method in which the chargeable powder for circuit formation is fixed on the ceramic green sheet by applying pressure. After that, the ceramic green sheets are laminated and fired, so there is no concern that the ceramic green sheets will shrink during the fixing process, and the circuit patterns on the multiple ceramic green sheets to be laminated will shift. The quality and reliability of the substrate can be improved.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 shows a cross-sectional view of a first embodiment of a charged powder for circuit formation according to the present invention. The circuit forming charged powder 10 has a structure in which the conductive metal powder 11 and the charge control agent 12 are uniformly dispersed in the pressure deformable resin 13.
[0015]
Here, the specific manufacturing method of the chargeable powder 10 for circuit formation is demonstrated. First, a conductive metal powder 11 made of spherical copper particles having an average particle diameter of 1.0 μm, a charge control agent 12 made of an azo-based metal dye, a pressure deformable resin 13 made of an ethylene / vinyl acetate copolymer, Were mixed at a weight ratio of 80 to 1:19.
[0016]
Next, the mixture is heat-melted and kneaded with a kneader, and coarsely pulverized with a cutter mill and finely pulverized with a jet mill. Subsequently, the chargeable powder 10 for circuit formation with an average particle diameter of 6.0 micrometers is obtained by airflow classification.
[0017]
According to the circuit-forming charged powder of the first embodiment described above, since the pressure-deformable resin is contained therein, the circuit-forming charged powder is pressed from the back surface or the front and back surfaces of the ceramic green sheet. In addition, the pressure-deformable resin plays a role of transferring or fixing the chargeable powder for circuit formation onto the ceramic green sheet.
[0018]
Therefore, by applying pressure to the circuit-forming chargeable powder, the circuit-forming chargeable powder can be transferred or fixed onto the ceramic green sheet. Therefore, the circuit-forming chargeable powder containing the pressure-deformable resin is electrophotographic. It can be used in a circuit pattern forming method for forming a circuit pattern on a ceramic green sheet by a method.
[0019]
FIG. 2 is a sectional view of a second embodiment of the charged powder for circuit formation according to the present invention. The circuit-forming chargeable powder 20 has a structure in which an outer wall 21 made of a pressure-deformable resin 13 is formed around the conductive metal powder 11, and the charge control agent 12 is fixed to the surface of the outer wall 21.
[0020]
Here, the specific manufacturing method of the chargeable powder 20 for circuit formation is demonstrated. First, conductive metal powder 11 made of spherical copper particles having an average particle diameter of 3.0 μm and pressure deformable resin 13 made of ethylene / vinyl acetate copolymer were mixed at a weight ratio of 80:19 to obtain a conductive property. A pressure-deformable resin 13 is adhered to the metal powder 11 by an electrostatic force.
[0021]
Next, a process in which a mechanical impact force is applied to the conductive metal powder 11 to which the pressure deformable resin 13 is attached, and an outer wall 21 made of the pressure deformable resin 13 is formed around the conductive metal powder 11. Get.
[0022]
Next, after mixing the conductive metal powder 11 with the outer wall 21 made of the pressure-deformable resin 13 and the charge control agent 12 made of an azo-based metal dye at a weight ratio of 99: 1, mechanical impact is performed. A process of applying force is performed, and the charge control agent 12 is fixed to the surface of the outer wall 21. The average particle diameter is 6.0 μm, and the conductive metal powder 11 is surrounded by the pressure deformable resin 13 around the conductive powder 11. An outer wall 21 is formed, and a chargeable powder 20 for circuit formation is obtained in which the charge control agent 12 is fixed on the surface.
[0023]
According to the charged powder for circuit formation of the second embodiment described above, the charge control agent is fixed to the surface of the outer wall formed around the conductive metal powder. A chargeable powder can be obtained. Therefore, by using this chargeable powder for circuit formation, the chargeability can be easily controlled, the printability is improved, and it is possible to cope with the formation of a circuit pattern with a narrow pitch, and a circuit pattern with a low sheet resistance can be formed. It becomes possible.
[0024]
Further, since the outer wall made of the pressure-deformable resin is formed around the conductive metal powder, the conductive metal powder can be prevented from appearing on the surface of the circuit-forming chargeable powder. Accordingly, deterioration of the chargeability due to the conductive metal powder can be prevented, so that the chargeability of the chargeable powder for circuit formation can be improved. As a result, the printability is further improved, and the circuit having a narrower pitch. It is possible to cope with pattern formation.
[0025]
FIG. 3 is a cross-sectional view of a third embodiment of the charged powder for circuit formation according to the present invention. The circuit-forming chargeable powder 30 has a structure in which an outer wall 31 made of the charge control agent 12 and the pressure-deformable resin 13 is formed around the conductive metal powder 11.
[0026]
Here, the specific manufacturing method of the chargeable powder 30 for circuit formation is demonstrated. First, a conductive metal powder 11 made of spherical copper particles having an average particle diameter of 5.0 μm, a charge control agent 12 made of an azo metal dye, and a pressure-deformable resin 13 made of an ethylene / vinyl acetate copolymer are weighted. Particles mixed and pulverized at a ratio of 1:19 are mixed at a weight ratio of 80:20, and particles composed of the charge control agent 12 and the pressure deformable resin 13 are adhered to the conductive metal powder 11 by electrostatic force.
[0027]
Next, a process in which mechanical impact force is applied to the conductive metal powder 11 to which particles composed of the charge control agent 12 and the pressure-deformable resin 13 are attached is performed around the conductive metal powder 11. Thus, a circuit-forming chargeable powder 30 having an average particle size of 6.0 μm and an outer wall 31 formed of 12 and the pressure-deformable resin 13 is obtained.
[0028]
According to the charged powder for circuit formation of the third embodiment described above, since the outer wall made of the charge control agent and the pressure deformable resin is formed around the conductive metal powder, the charge control agent is separately formed in the circuit. This eliminates the need to adhere to the surface of the chargeable powder for circuit use and simplifies the manufacturing process of the chargeable powder for circuit formation. Therefore, cost reduction of the chargeable powder for circuit formation is realizable.
[0029]
FIG. 4 shows a configuration diagram of an electrophotographic system used in the first embodiment of the circuit pattern forming method according to the present invention. The circuit pattern forming method on the ceramic green sheet includes a charging process in which the surface of the photoconductor 42 is charged by the corona charger 41, and the surface of the photoconductor 42 rotating in the direction of arrow A is irradiated with a laser beam 43 to obtain a desired latent image. An exposure process for forming an image pattern (not shown), a developing process for electrostatically adsorbing the circuit forming charged powders 10 to 30 to the latent image pattern on the surface of the photoreceptor 42 by the supply means 44, and the back surface of the ceramic green sheet 45 The transfer unit 46 applies a charge having a polarity opposite to that of the circuit forming charged powders 10 to 30 to the ceramic green sheet 45, and develops the circuit forming charged powders 10 to 30 developed on the latent image pattern into the ceramic green sheet 45. The ceramic green sheet 45 to which the transfer process for transferring up and the charged powder for circuit formation 10 to 30 is transferred is rotated in the direction of arrow a. Circuit formation transferred onto the ceramic green sheet 45 by passing between the pressure rollers 47 and pressing the circuit forming chargeable powders 10 to 30 on the ceramic green sheet 45 from the front and back surfaces of the ceramic green sheet 45 It comprises a fixing step of fixing the chargeable powder 10 to 30 and forming a circuit pattern (not shown).
[0030]
The circuit forming chargeable powders 10 to 30 are formed in a step of firing the ceramic green sheet 45 after the circuit forming chargeable powders 10 to 30 are fixed on the ceramic green sheet 45 and the circuit pattern is formed. Since the pressure-deformable resin 13 disappears, the circuit pattern is finally formed only from the conductive metal powder 11 (FIGS. 1 to 3).
[0031]
According to the circuit pattern forming method of the first embodiment described above, the fixing step of fixing the circuit forming chargeable powder transferred onto the ceramic green sheet onto the ceramic green sheet is carried out for circuit formation on the ceramic green sheet. Since the charging is performed by pressurizing the chargeable powder, it is not necessary to heat the ceramic green sheet in the fixing step. Therefore, since the shrinkage of the ceramic green sheet can be prevented, the circuit pattern on the ceramic green sheet can be prevented from shifting when a plurality of ceramic green sheets are laminated.
[0032]
FIG. 5 shows a configuration diagram of an electrophotographic system used in the second embodiment of the circuit pattern forming method according to the present invention. The circuit pattern forming method on the ceramic green sheet includes a charging process in which the surface of the photoconductor 52 is charged by the corona charger 51, and the surface of the photoconductor 52 rotating in the direction of arrow A is irradiated with a laser beam 53 to obtain a desired latent image. An exposure process for forming an image pattern (not shown), a developing process for electrostatically adsorbing the charged powder for circuit formation 10 to 30 to the latent image pattern on the surface of the photoreceptor 52 by the supply means 54, and a circuit on the latent image pattern By stacking the ceramic green sheet 55 on the chargeable powder 10-30 for forming, and pressing the chargeable powder 10-30 for circuit formation on the ceramic green sheet 55 from the back surface of the ceramic green sheet 55 with the pressure roller 56, The circuit forming chargeable powder 10 to 30 is transferred onto the ceramic green sheet 55 and fixed thereon, and then the ceramic green sheet 55 is fixed. It consists of transferring and fixing step of forming a circuit pattern (not shown).
[0033]
Similarly to the circuit pattern forming method of the first embodiment, the circuit forming chargeable powders 10 to 30 are transferred onto the ceramic green sheet 55, fixed, and the circuit pattern is formed. Since the pressure-deformable resin 13 constituting the circuit-forming chargeable powders 10 to 30 disappears in the firing step, the circuit pattern is finally formed only of the conductive metal powder 11 (FIGS. 1 to 3). Will be.
[0034]
According to the circuit pattern forming method of the second embodiment described above, the transfer process and the fixing process are simultaneously performed by pressing the circuit forming chargeable powder on the latent image pattern of the photoreceptor from the back surface of the ceramic green sheet. Therefore, the circuit pattern forming method is simplified, and the electrophotographic system used therefor is also simplified.
[0035]
FIG. 6 shows a cross-sectional view of an embodiment of a multilayer wiring board according to the present invention. The multilayer wiring board 60 includes first to third ceramic green sheets 61a to 61c. Then, on the first and second ceramic green sheets 61a and 61b, the circuit pattern chargeable powders 10 to 30 of the first to third embodiments described above are used, and the circuit pattern 62a, 62b is printed. Next, the first to third ceramic green sheets 61a to 61c are stacked, pressure is applied, and they are integrally molded and then fired.
[0036]
The circuit patterns 62a and 62b on the first and second ceramic green sheets 61a and 61b are connected by a via hole 63. The via hole 63 is formed by an existing technique. For example, there is a method of press-fitting a conductor for each via hole using a conductor drawing device. In this case, if the via holes 63 are formed after the circuit patterns 62a and 62b are formed by electrophotography, the powder may damage the nozzle of the drawing machine. Therefore, before the circuit patterns 62a and 62b are formed, A via hole 63 is preferably formed.
[0037]
According to the multilayer wiring board described above, a circuit pattern is printed on the ceramic green sheet by electrophotography using a circuit pattern forming method in which the chargeable powder for circuit formation is fixed on the ceramic green sheet by pressurization, and then Since these ceramic green sheets are laminated and fired, there is no concern that the ceramic green sheets will shrink during the fixing process and the circuit patterns on the ceramic green sheets to be laminated will shift. Quality and reliability can be improved.
[0038]
In the first to third embodiments of the above-described charged powder for forming a circuit, the case where copper is used as the conductive metal powder has been described. However, the simple substance of gold, silver, platinum, nickel, palladium, tungsten and molybdenum is described. Alternatively, the same effect can be obtained by using an alloy composed of two or more of these.
[0039]
Further, the case where an ethylene / vinyl acetate copolymer is used as the pressure deformable resin has been described. However, the pressure deformable resin is a low molecular weight resin that is plastically deformed at room temperature when pressurized, and is made of polyethylene, styrene / butadiene rubber. Similar effects can be obtained by using a wax-like, rubber-like resin, phenolic resin, petroleum resin, polycarbonate, silicone resin, fluorine resin, urethane resin, or the like.
[0040]
Further, the case where an azo metal-containing dye is used as the charge control agent has been described. However, the chlorinated paraffin, the chlorinated polyester, the polyester having excess acid groups, and the sulfonylamine naphthene of copper phthalocyanine, which are charge control agents for negative charge, have been described. The same effect can be obtained by using a simple substance such as an acid metal salt, a metal salt of a fatty acid and a resin acid soap, or a mixture of two or more of these.
[0041]
Moreover, although the case where the adhesion reinforcing agent was not included in the chargeable powder for circuit formation was described, the adhesion reinforcing agent may be included. When the adhesive reinforcing agent is included in the circuit forming charged powder, the adhesive reinforcing agent is a conductive metal powder that forms the circuit pattern when firing the ceramic green sheet on which the circuit pattern is formed. It will play the role of strengthening the adhesion with the fired ceramic sheet. Therefore, since the adhesive strength between the fired ceramic sheet and the circuit pattern is improved after firing, it is possible to prevent the circuit pattern from being peeled from the ceramic sheet. Examples of the adhesion reinforcing agent include silica, borosilicate glass, soda lime, lead glass and aluminosilicate glass, or a glass made of a mixture of two or more of these, or a ceramic made of alumina, ferrite, or the like. .
[0042]
Furthermore, as shown in FIG. 7, the conductive metal powder 11 may be a secondary powder made of an aggregate obtained by aggregating a plurality of primary powders 14. In this case, after the conductive powder for circuit formation is fixed on the ceramic green sheet, the circuit pattern is formed, and then the ceramic green sheet is fired, the conductive metal powder 11 that is the secondary powder is the primary powder. Since the powder 14 is divided, the filling of the circuit pattern with the primary powder 14 constituting the conductive metal powder 11 becomes dense, so that the sheet resistance of the circuit pattern can be further reduced and the loss of the circuit pattern can be further reduced. As a result, the multilayer wiring board obtained using this circuit forming chargeable powder can be used in a higher frequency region. In particular, in order to obtain a spherical secondary powder, the particle size of the primary powder is desirably in the range of 1/5 to 1/20 of the particle size of the chargeable powder for circuit formation.
[0043]
In the third embodiment of the above-described circuit-forming chargeable powder, a structure in which a charge control agent is fixed to the outer periphery of the circuit-formable charge powder, that is, an outer wall made of a charge control agent and a pressure-deformable resin. The same effect can be obtained even if the charge control agent is fixed on the surface.
[0044]
【The invention's effect】
According to the circuit pattern forming method of the present invention , since the pressure- forming resin is included in the circuit-forming chargeable powder, when the circuit-forming chargeable powder is pressed from the back surface or the front and back surfaces of the ceramic green sheet. The pressure-deformable resin plays a role of transferring or fixing the charged powder for circuit formation onto the ceramic green sheet.
[0045]
Therefore, by pressurizing the chargeable powder for circuit formation, the chargeable powder for circuit formation can be transferred or fixed on the ceramic green sheet, without heating at a temperature at which the ceramic green sheet contracts, A circuit pattern can be formed on the ceramic green sheet by the electrophotographic method using the chargeable powder for circuit formation.
[0046]
In this case, when the conductive metal powder is a secondary powder consisting aggregates by agglomerating a plurality of primary powder is allowed to settle the charged powder circuit formed on the ceramic green sheet, after forming a circuit pattern, ceramic In the step of firing the green sheet, the conductive metal powder that is the secondary powder is divided into primary powders.
[0047]
Therefore, the filling of the circuit pattern with the conductive metal powder becomes dense, the sheet resistance of the circuit pattern can be further reduced, and the loss of the circuit pattern can be further reduced.
[0048]
According to the circuit pattern forming method of the present invention, the circuit forming charged powder transferred on the ceramic green sheet is fixed on the ceramic green sheet, and the circuit forming charged powder on the ceramic green sheet is added. Since it is performed by pressing, it is not necessary to apply heat that causes the ceramic green sheet to shrink to the ceramic green sheet in the fixing step.
[0049]
Therefore, since the shrinkage of the ceramic green sheet can be prevented, the circuit pattern on the ceramic green sheet can be prevented from shifting when a plurality of ceramic green sheets are laminated.
[0050]
According to the circuit pattern forming method of the present invention, the transfer process and the fixing process can be performed simultaneously by pressing the chargeable powder for circuit formation on the latent image pattern of the photoreceptor from the back surface of the ceramic green sheet. The pattern forming method is simplified, and the electrophotographic system used therefor is also simplified.
[0051]
According to the multilayer wiring board of the present invention, a circuit pattern is printed on the ceramic green sheet by electrophotography using a circuit pattern forming method in which the chargeable powder for circuit formation is fixed on the ceramic green sheet by applying pressure. After that, the ceramic green sheets are laminated and fired, so there is no concern that the ceramic green sheets will shrink during the fixing process, and the circuit patterns on the multiple ceramic green sheets to be laminated will shift. The quality and reliability of the substrate can be improved.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a first embodiment of a charged powder for circuit formation according to the present invention.
FIG. 2 is a sectional view of a second embodiment of the charged powder for circuit formation according to the present invention.
FIG. 3 is a cross-sectional view of a third embodiment of the charged powder for circuit formation according to the present invention.
FIG. 4 is a configuration diagram of an electrophotographic system used in a first embodiment of a circuit pattern forming method according to the present invention.
FIG. 5 is a configuration diagram of an electrophotographic system used in a second embodiment of a circuit pattern forming method according to the present invention.
FIG. 6 is a cross-sectional view of an embodiment of a multilayer wiring board according to the present invention.
7 is a cross-sectional view showing an example of a conductive metal powder constituting the circuit-forming chargeable powder of FIGS. 1 to 3. FIG.
FIG. 8 is a configuration diagram of an electrophotographic system used in a conventional circuit pattern forming method.
FIG. 9 is a cross-sectional view showing a conventional charged powder for circuit formation.
[Explanation of symbols]
10-30 Chargeable powder for circuit formation 11 Conductive metal powder 12 Charge control agent 13 Pressure deformable resin 14 Primary powder 42, 52 Photoconductors 45, 55, 61a-61c Ceramic green sheet 60 Multilayer wiring boards 62a, 62b Circuit pattern

Claims (4)

A charging step for charging the entire surface of the photoconductor, an exposure step for forming an electrostatic latent image pattern on the photoconductor, a conductive metal powder, a pressure-deformable resin, and a charge control agent on the latent image pattern a developing step of the charged powder for circuit formation is deposited by an electrostatic force consisting of, a transfer step of transferring the circuit-forming charged powder on the latent image pattern into the ceramic green sheet, table of the ceramic green sheet By pressing the circuit-forming chargeable powder on the ceramic green sheet from the back side, the circuit-formed transfer material is transferred onto the ceramic green sheet without heating at a temperature at which the ceramic green sheet contracts . A circuit pattern is formed on the ceramic green sheet by using an electrophotographic method including a fixing step of fixing a chargeable powder. Characterized by the circuit pattern forming method. A charging step for charging the entire surface of the photoconductor, an exposure step for forming an electrostatic latent image pattern on the photoconductor, a conductive metal powder, a pressure-deformable resin, and a charge control agent on the latent image pattern a developing step of adhering by electrostatic charged powder circuit formed consisting, on the circuit-forming charged powder on the latent image pattern, overlapping the ceramic green sheet, the latent image from the back side of the ceramic green sheet By pressing the circuit forming chargeable powder on the pattern, the circuit forming chargeable powder is transferred onto the ceramic green sheet without being heated at a temperature at which the ceramic green sheet contracts , and then fixed. using an electrophotographic method comprising a transfer-fixing step of, and forming a circuit pattern on the ceramic green sheet, the circuit Turn-forming method. 3. The circuit pattern forming method according to claim 1, wherein the conductive metal powder is a secondary powder made of an aggregate obtained by aggregating a plurality of primary powders. A multilayer wiring board comprising: laminating and firing the ceramic green sheets on which the circuit pattern is printed by the circuit pattern forming method according to claim 1 .

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