Patent Application
20170207026
This application claims benefit of priority to Japanese Patent Application 2016-007714 filed Jan. 19, 2016, the entire content of which is incorporated herein by reference.
The present disclosure relates to a method of forming an electrode pattern by an ink-jet method, and a method of manufacturing an electric component by using the electrode pattern.
A conventional electrode pattern forming method is disclosed by, for example, Japanese Patent Laid-open No. 1996-222475. Japanese Patent Laid-open No. 1996-222475 discloses that a head provided to an ink-jet device sprays droplets of conductive ink to apply the conductive ink onto a principal surface of a work piece (for example, a ceramic green sheet, a resin film, or a mounting substrate) placed on a stage so as to form an internal electrode pattern on the principal surface of the work piece. In this case, the work piece is moved relative to the head in two directions (X direction and Y direction) orthogonal to each other in a substantially horizontal plane.
Japanese Patent Laid-open No. 1996-222475 further discloses a lamination process in which a work piece on which an internal electrode is formed is laminated and subjected to pressure bonding, a firing process that cuts and fires a laminated structure manufactured through the lamination process, and a forming process that forms a side electrode on a fired body manufactured through the firing process.
In the conventional electrode pattern forming method, conductive ink is sprayed at a fixed resolution. Thus, it has been difficult to form an electrode pattern having a desired thickness onto each of a plurality of areas on an identical surface.
Thus, the present disclosure is intended to provide an electrode pattern forming method capable of forming an electrode pattern having a desired thickness for each of a plurality of areas on an identical surface by an ink-jet method, and a method of manufacturing an electric component including the electrode pattern.
A first aspect of the present disclosure is a method of forming an electrode pattern including a first conductive portion and a second conductive portion connected with each other onto a work piece by an ink-jet method. A first area corresponding to at least part of the first conductive portion and a second area corresponding to at least part of the second conductive portion are defined on an identical surface of the work piece.
Conductive ink droplets are ejected toward the first area and the second area to form the first conductive portion and the second conductive portion. At least one of a resolution of conductive ink droplets and the number of iterations of recoating is different between the first area and the second area.
A second aspect of the present disclosure is a method of manufacturing an electric component, the method forming and firing a laminated structure including at least one work piece provided with the electrode pattern formed by the method according to the first aspect.
The above-described aspects can provide an electrode pattern forming method capable of forming an electrode pattern having a desired thickness for each of a plurality of areas in an identical surface by an ink-jet method, and a method of manufacturing an electric component including the electrode pattern.
The following first describes an ink-jet device for forming an electrode pattern in detail with reference to
First, arrows in each drawing will be described. In
Configuration and Operation of Ink-jet Device
In
The head 11 includes a plurality of nozzles arrayed in, for example, the x direction. Each of the nozzles ejects supplied conductive ink as an ink droplet by, for example, a piezoelectric scheme, a thermal scheme, or an electrostatic scheme. The ink droplet lands on a work piece and spreads to draw a substantially circular dot. In the ink-jet device 1, one or a plurality of the heads 11 may be arranged in line in, for example, the x direction, or may be arranged in a plurality of lines such that the array of the nozzles differs in the y direction to achieve an increased resolution.
An exemplary specification of a head is as follows.
The dot drawn by the head 11 has a diameter, in other words, a dot diameter approximately between 5 μm and 100 μm inclusive depending on an ejection condition.
The conductive ink is, for example, metal ink obtained by dispersing particles of a metal including nickel, silver, or copper in a solvent. An exemplary specification of the metal ink is as follows.
The stage 12 includes a placement surface on which a strip-shaped or elongated work piece w is placed. In the present embodiment, the stage 12 is shaped in a table including a placement surface parallel to the xy plane. However, the present disclosure is not limited thereto, and the stage 12 may be shaped in a roll. Examples of the work piece w include a ceramic green sheet, a resin film, or a mounting substrate (bare board). The stage 12 is provided with a vacuum suction unit (not illustrated) configured to fix the work piece w to an upper surface of the stage 12 by sucking the work piece w from below. The stage 12 may be provided with a temperature adjusting unit configured to facilitate drying of the ink by heating the work piece w to a predetermined temperature, for example, between 30° C. and 95° C. inclusive.
The movement mechanisms 13 to 15 relatively move the head 11 and the stage 12. In the present embodiment, the movement mechanism 13 moves the stage 12 in the left-right direction, and the movement mechanism 14 moves the stage 12 in the front-back direction. The movement mechanism 15 moves the head 11 in the top-bottom direction. When shaped in a roll, the stage 12 can be relatively moved through rotation.
In the ink-jet device 1, while the head 11 and the stage 12 are relatively moved, a plurality of dots are drawn on the work piece w through a plurality of times of ink ejection from the head 11 to the work piece w, thereby forming a pattern. A scanning operation refers to drawing of dots while relatively moving each of the head 11 and the stage 12 in one direction along, for example, the y direction orthogonal to the head 11 including the plurality of nozzles arrayed in the x direction. The relative movement in one direction is, for example, backward or forward movement without reversing in, for example, the y direction. The formation of the pattern is performed through a single scanning operation on the work piece w or through a plurality of times of scanning operations on the same region of the work piece w. Recoating refers to formation of a pattern through a scanning operation over a pattern formed through the previous scanning operation, in particular, by performing a plurality of times of scanning operations on the same region.
In a scanning operation, the direction in which the nozzles of the head 11 are arrayed does not need to be completely orthogonal to the direction in which the head 11 and the stage 12 are relatively moved, but these directions may be oblique to each other to some extent. When the pattern is formed through a plurality of times of scanning operations, ink droplets may be ejected under the same condition through all scanning operations or under different conditions between the scanning operations. In addition, the same head may be used through a plurality of times of scanning operations, or a plurality of heads or a plurality of ink-jet devices may be prepared and used for the respective scanning operations.
As illustrated in
The following describes an electrode pattern forming method according to a first embodiment with reference to
The conventional ink-jet device receives setting of a fixed resolution (the reciprocal of the resolution is referred to as a drop-landing interval) before the formation of the electrode pattern 2. The conventional ink-jet device ejects conductive ink droplets toward the work piece at a constant interval in accordance with the set resolution. In this case, the line portion and the solid portion are expected to have thicknesses equivalent to each other. However, when the thickness of the line portion is reduced to be small, no overlapping of conductive ink droplets is provided in the width direction, or the overlapping is smaller than in the length direction. Accordingly, the line portion receives a smaller number of droplets per unit area on the work piece than the solid portion, and as a result, the thickness of the line portion becomes smaller than that of the solid portion.
In an ink-jet method, the viscosity of conductive ink droplets is set to be small as appropriate to achieve excellent ejection performance of the droplets. Thus, the conductive ink on the work piece is likely to flow right after ejection. In addition, the conductive ink in the line portion tends to be moved toward the solid portion due to the effect of surface tension.
As described above, in the conventional ink-jet device, when the electrode pattern 2 including the line portion and the solid portion connected with each other is formed, the solid portion tends to be thick and the line portion tends to be thin. For example, when a work piece on which such an electrode pattern 2 is formed is laminated and fired, a structural defect is likely to occur in the solid portion, and a failure such as breaking, reduction of a current resistant property, or degradation of a high frequency characteristic is likely to occur in the line portion. In the work piece on which such an electrode pattern 2 is formed, a failure such as breaking, reduction of the current resistant property, or degradation of the high frequency characteristic is likely to occur in the line portion. For example, when a laminated structure of a work piece on which such an electrode pattern 2 is formed and fired, a structural defect is likely to occur in the solid portion.
In the present embodiment, as illustrated in
After the electrode pattern 2 is formed, the electrode pattern 2 starts drying at a temperature of 250° C. or lower. Since the conductive ink still has flowability right after the formation of the electrode pattern 2, the conductive ink in the line portion tends to be moved toward the solid portion due to the effect of surface tension. However, as described above, the resolution R2 is higher than the resolution R1, and the degree of overlapping of conductive ink droplets is higher in the line portion than in the solid portion. As a result, the line portion is thicker than the solid portion. Thus, the line portion can be prevented from being extremely thin when the conductive ink in the line portion is moved toward the solid portion to some extent. Accordingly, for example, when the work piece w on which the electrode pattern 2 is formed is laminated and fired to manufacture an electric component, a structural defect is unlikely to occur in the solid portion, and a failure such as breaking, reduction of the current resistant property, or degradation of the high frequency characteristic is unlikely to occur in the line portion.
Upon completion of the drying process described above, the electrode pattern 2 including the conductive portions 21 and connected with each other is completely formed on the identical principal surface of the work piece w.
The following describes an electrode pattern forming method according to a second embodiment with reference to
The bit map data BMa according to the first embodiment includes data on a pair of a two-dimensional shape and a resolution for each area. However, as illustrated in
In the present embodiment, the CPU 161 forms the electrode pattern 2 on the identical principal surface of the work piece w in accordance with the bit map data BMb. Specifically, as illustrated in an upper part of
After the recoating as described above, the conductive ink is dried, and as a result, the electrode pattern 2 including the conductive portions 21 and 22 connected with each other (refer to
In the present embodiment, since the drying time is provided for each scanning operation as described above, conductive ink droplets on the work piece w are dried to some extent, thereby reducing bleeding of the conductive ink and/or flow of the conductive ink into the solid portion.
The following describes an electrode pattern forming method according to a third embodiment with reference to
As illustrated in
In the present embodiment, the CPU 161 forms the electrode pattern 2 onto an identical principal surface of the work piece w in accordance with the bit map data BMc. Specifically, as illustrated in an upper part of
After the recoating as described above, the conductive ink is dried, and as a result, the electrode pattern 2 including the conductive portions 21 and 22 connected with each other (refer to
Since the resolution R1 of the solid portion is large, the conductive ink is prompted to flow from the line portion to the solid portion, which is a unique effect of the present embodiment. As a result, the conductive ink can have an increased coverage in the first area 31.
The following describes an electrode pattern forming method according to a fourth embodiment with reference to
In comparison with the bit map data BMb, the bit map data BMd includes information indicating the two-dimensional shape of an area to be coated at each iteration of recoating as illustrated in
In the present embodiment, the CPU 161 forms the electrode pattern 2 onto an identical principal surface of the work piece w in accordance with the bit map data BMd. Specifically, as illustrated in
The same idea as that in the fourth embodiment (coat the second area 32 first) is applicable in any other embodiment.
The following describes an electrode pattern forming method according to a fifth embodiment with reference to
As illustrated in
In the present embodiment, the CPU 161 forms the electrode pattern 2 onto an identical principal surface of the work piece w in accordance with the bit map data BMe described above. Specifically, as illustrated in an upper part of
In such recoating, the line portion and the solid portion are not connected at the first coating, and thus the conductive ink can be prevented from flowing from the line portion to the solid portion. Then, both parts are connected with each other at the second coating. In the present embodiment, the line portion has a resolution higher than that in the solid portion, and thus the line portion has a thickness larger than that in the solid portion as illustrated in a lower part of
The third area 33 according to the present embodiment is applicable in any of the first to fourth embodiments.
In the fifth embodiment described above, the resolution of the conductive ink and the number of iterations of recoating are constant for the third area 33. However, the present disclosure is not limited thereto, and the bit map data BMe may be defined appropriately so that the number of iterations of coating of conductive ink droplets in the third area 33 decreases at stages from the second area 32 toward the first area 31 as illustrated in
When the line portion 22 includes a plurality of conductive ink droplets in the width direction, the width of the third area 33 in the front-back direction may be set to decrease at stages from the second area 32 toward the first area 31.
As described above, the thickness is set to gradually change between the line portion and the solid portion by setting the resolution, the number of iterations of recoating, or the width of the third area 33, thereby further reducing the flow of the conductive ink from the second area 32 to the first area 31.
The following describes a method of manufacturing an electric component using the electrode pattern forming method according to each of the first to fifth embodiments. The electric component is, for example, a laminated ceramic electric component.
First, deposition and drying of a ceramic green sheet are performed as a first process. The deposition is performed by using a device such as a die coater, a doctor blade, a roll coater, or an ink-jet coater as appropriate. This deposition device forms a ceramic sheet by applying ceramic slurry onto a support body. The ceramic slurry is obtained by dissolving and dispersing, into an organic solvent (or an aqueous solvent), ceramic powder to which a resin component is added. The support body may be, for example, an elongated or strip-shaped resin film, metal roll, metal drum, metal belt, or metal plate.
In the first process, the ceramic sheet formed by the deposition device is dried by a drying device. More specifically, the drying device dries the ceramic sheet by a method through, for example, heated air, heating of the support body, or vacuum dry to obtain a ceramic green sheet. The drying may be performed by any method suitable for the property of the solvent.
In a subsequent second process, a ceramic green sheet on which a predetermined internal electrode pattern is formed is manufactured by the methods according to the first to fifth embodiments.
In a subsequent third process, first, a predetermined number of the ceramic green sheets on each of which the internal electrode pattern is formed are laminated on a support plate, and then subjected to pressure bonding. In this manner, a ceramic laminated structure is manufactured. The lamination and pressure bonding processes may be performed by using a typical laminator or devices disclosed by Japanese Patent Laid-open No. 2005-217278 and Japanese Patent Laid-open No. 2011-258928. The lamination and pressure bonding processes may be performed before or after separation from the support body.
The ceramic laminated structure manufactured through the lamination and pressure bonding processes is pressed by pressurization, and then cut into a desired size. Thereafter, a laminated ceramic electric component is completely formed through a firing process of firing at a temperature, for example, between 800° C. and 1200° C. and a process of forming an external electrode.
The laminated structure includes at least one work piece on which a predetermined electrode pattern is formed by the methods according to the first to fifth embodiments. Another method of forming a laminated structure repeats a process in which ink or paste including a work piece base material such as ceramic particle is prepared, a first work piece base material layer is formed onto a support body by a printing method such as the ink-jet method or a screen printing method, and then a first electrode pattern is formed on the work piece base material layer, and in addition, a second work piece base material layer is formed through printing of the ink or paste including the work piece base material onto the first work piece base material layer on which the first electrode pattern is formed, and a second electrode pattern on the second work piece base material layer is formed. In this case, too, the effect of the present disclosure can be obtained by forming a predetermined electrode pattern onto at least one work piece base material layer by the methods according to the first to fifth embodiments.
Typically, in the process of firing a ceramic electric component, the electrode pattern 2 contracts more than ceramic. Thus, when the solid portion having a large area is thick, the amount of contraction largely differs across an interface between a ceramic part and the solid portion. As a result, structural defects such as cracking and delamination are likely to occur in the solid portion. When the line portion is thin, a failure such as breaking, reduction of the current resistant property, or degradation of the high frequency characteristic is likely to occur.
However, as described above, the electrode pattern 2 in which reduction in the thickness of the line portion can be prevented can be formed on the ceramic green sheet by the methods according to the first to fifth embodiments. In the sixth embodiment, the electric component is manufactured by using such a ceramic green sheet, and thus a structural defect is unlikely to occur in the solid portion, and a failure such as breaking, reduction of the current resistant property, or degradation of the high frequency characteristic is unlikely to occur in the line portion.
In the process of manufacturing a ceramic electric component, a plurality of ceramic green sheets on each of which an internal electrode pattern is formed are laminated, and thus, in plan view along a lamination direction, an electrode pattern on a ceramic green sheet overlaps with an electrode pattern on another ceramic green sheet in some cases. If a large number of electrode patterns overlap with each other, a structural defect is potentially generated in the manufacturing process, or the flatness of a surface of a formed ceramic electric component is potentially affected.
In the present embodiment, in each electrode pattern 2 (refer to
When a solid electrode pattern is formed on the work piece w by the ink-jet method and dried, a peripheral portion of the electrode pattern 2 is likely to be thicker than an inner portion thereof due to the coffee stain phenomenon.
In the present embodiment, to achieve the flatness of the electrode pattern 2 described above, the peripheral portion assumed to be affected by the coffee stain phenomenon is designed to be thinner than the inner portion. In other words, the first conductive portion 21 is defined to be the peripheral portion of the electrode pattern 2, and the second conductive portion 22 is defined to be the inner portion. With these definitions, the electrode pattern 2 is formed on the work piece w by the methods according to the first to fifth embodiments. As a result, right after the electrode pattern 2 is formed on the work piece w, the thickness of the conductive ink is larger in the second area 32 (inner portion) than in the first area 31 (peripheral portion) as illustrated in a left part of
However, after drying, the second conductive portion 22 (inner portion) has a thickness substantially the same as that of the first conductive portion 21 (peripheral portion) as illustrated in a right part of
The following describes an electrode pattern forming method according to a ninth embodiment with reference to
As described in the first embodiment, when the electrode pattern 2 as illustrated in
In the present embodiment, as illustrated in
In the present embodiment, the CPU 161 forms the electrode pattern 2 on the principal surface of the work piece w in accordance with the bit map data BMf as described above. Thereafter, the electrode pattern 2 is dried. However, in the present embodiment, the line portion and the solid portion are not connected with each other, and the resolution R2 is higher than the resolution R1, and thus the line portion has a larger degree of overlapping of conductive ink droplets than the solid portion. As a result, the line portion is thicker than the solid portion. Accordingly, the line portion can be prevented from being thinner than the solid portion. Thus, for example, when the work piece w on which such an electrode pattern 2 is formed is laminated and fired to manufacture an electric component, a structural defect is unlikely to occur in the solid portion, and a failure such as breaking, reduction of the current resistant property, or degradation of the high frequency characteristic is unlikely to occur in the line portion.
The following describes a method of manufacturing an electric component by using the electrode pattern forming method according to the ninth embodiment. The manufacturing method according to the present embodiment and an effect thereof differs from that of the seventh embodiment in that the content of the second process in the seventh embodiment is replaced with the content of the electrode pattern forming method according to the ninth embodiment. There is no other difference between the embodiments, and thus a description of any common part will be omitted.
The electrode pattern forming methods according to the present disclosure are preferable for manufacturing of an electric component and a circuit board. The methods of manufacturing an electric component according to the present disclosure are preferable for manufacturing of, for example, a chip capacitor.
The first area 31 is defined to be an area in which the first conductive portion 21 (solid portion) is to be formed, and the second area 32 is defined to be an area in which the second conductive portion 22 (line portion) is to be formed. However, the first area 31 only needs to correspond to at least part of the first conductive portion 21, and the second area 32 only needs to correspond to at least part of the second conductive portion 22. In other words, differences in the resolution and the number of iterations of recoating do not need to be provided between the entire area in which the first conductive portion 21 is to be formed and the entire area in which the second conductive portion 22 is to be formed. Differences in the resolution and the number of iterations of recoating may be provided between at least part of the area in which the first conductive portion 21 is to be formed and at least part of the area in which the second conductive portion 22 is to be formed.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2016-007714 | Jan 2016 | JP | national |
