JP4595183B2 - Ceramic electronic component and method for manufacturing the same, multilayer ceramic electronic component and method for manufacturing the same - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for manufacturing a ceramic electronic component, a ceramic electronic component obtained by the manufacturing method, a method for manufacturing a multilayer ceramic electronic component, and a multilayer ceramic electronic component obtained by the manufacturing method. The present invention relates to an improvement for increasing the bonding force between a ceramic portion and a conductor film in a ceramic electronic component or a multilayer ceramic electronic component.
[0002]
[Prior art]
For example, when manufacturing a multilayer ceramic electronic component such as a multilayer ceramic substrate, a step of forming a conductor film on a ceramic green sheet is performed. In forming such a conductor film, typically, a method using a conductive paste or a method using a metal foil is employed.
[0003]
However, each of these two methods has advantages, but both have problems to be solved.
[0004]
[Problems to be solved by the invention]
According to the method using the conductive paste, the glass component contained in each of the conductive paste and the ceramic green sheet is between the ceramic particles in the ceramic green sheet and between the metal particles in the conductive paste in the firing step. Each of them spreads and forms an anchor structure, and the conductor film provided by the conductive paste can be firmly bonded to the ceramic layer provided by the ceramic green sheet.
[0005]
However, the conductor film formed of the conductive paste does not give a completely dense structure after firing. This is because the volume of the organic component contained in the conductive paste burned out becomes a cavity, and this cavity is not completely filled even by sintering of the metal particles. For this reason, in recent years, it has become difficult to ensure the reliability of the conductor film as the conductor film is required to be thinner and the firing temperature is lowered.
[0006]
On the other hand, according to the method using a metal foil, since it has a dense structure before firing, it is easy to thin the conductor film formed thereby. Further, the surface of the conductor film can be made smoother than the conductor film made of a conductive paste. At high frequencies above millimeter waves, signal scattering due to surface roughness and internal defects dominates, so metal foils are also advantageous in this respect.
[0007]
Further, in the case of using a metal foil, etching is typically applied for the patterning, but according to the patterning by such etching, compared to the case where the screen printing of the conductive paste described above is applied. A minute pattern can be easily produced.
[0008]
In addition, as a method for forming the metal foil, there are a method for forming the metal foil on the carrier film by plating and a method for forming the metal foil by a thin film process such as sputtering. Is used industrially.
[0009]
However, the method of forming the conductor film with the metal foil has a problem that the bonding strength between the conductor film and the ceramic is low.
[0010]
Regarding the bonding strength, generally, the glass component plays a large role in bonding the conductor film and the ceramic. In the method using the conductive paste described above, the glass component wets and spreads between the ceramic particles and between the metal particles, forms an anchor structure, and firmly bonds the two together. In addition, the oxide acts to improve the wettability with the glass and increase the bonding strength by chemical bonding with the glass. Therefore, an oxide may be added to the conductive paste in addition to the glass frit.
[0011]
However, when a metal foil is to be formed by plating as described above, it is extremely difficult to deposit an oxide by such plating, and the conductor film obtained by plating is dense. There is no space through which the components can penetrate.
[0012]
For this reason, it is not so easy to increase the bonding strength between the conductor film and the ceramic using the metal foil.
[0013]
The above description has been given for a multilayer ceramic electronic component such as a multilayer ceramic substrate. However, the same problem is caused by a structure other than the multilayer ceramic electronic component having a structure in which a conductor film is formed on a ceramic body. Also encountered in ceramic electronic components.
[0014]
Accordingly, an object of the present invention is to provide ceramic electronic components and multilayer ceramic electronic component manufacturing methods, ceramic electronic components and multilayer ceramic electronic components obtained by these manufacturing methods, which can solve the above-described problems. Is to try.
[0015]
[Means for Solving the Problems]
The present invention is first directed to a method for manufacturing a ceramic electronic component. In order to solve the technical problems described above, the method of manufacturing a ceramic electronic component includes a step of preparing a metal foil lined with a carrier film, and a step of oxidizing a surface facing the outside of the metal foil lined with a carrier film. And a step of transferring the metal foil from the carrier film onto the raw ceramic molded body in a state where the oxidized surface of the metal foil is opposed to the raw ceramic molded body, and the raw ceramic to which the metal foil is transferred And a step of firing the molded body in a reducing atmosphere, and the raw ceramic molded body contains a glass component .
[0016]
The present invention is also directed to a method for manufacturing a multilayer ceramic electronic component. In order to solve the above-described technical problem, the multilayer ceramic electronic component manufacturing method includes a step of preparing a metal foil lined with a carrier film, and a first direction facing the outside of the metal foil lined with a carrier film. A step of oxidizing the surface, a step of transferring the metal foil from the carrier film onto the ceramic green sheet with the first surface facing the ceramic green sheet, and a step of transferring the metal foil transferred onto the ceramic green sheet. A step of oxidizing the second surface facing outward, a step of stacking a plurality of ceramic green sheets to produce a raw laminate, and a step of firing the raw laminate in a reducing atmosphere. In addition, the ceramic green sheet includes a glass component .
[0017]
In such a method of manufacturing a ceramic electronic component or a multilayer ceramic electronic component, the metal foil preferably contains at least one selected from silver, palladium, copper, nickel, molybdenum, tungsten and tin.
[0018]
Moreover, when preparing the metal foil backed by the carrier film, it is preferable to form the metal foil on the carrier film by plating.
[0019]
In oxidizing the surface of the metal foil, it is preferable to heat-treat the metal foil in an adjusted atmosphere.
[0020]
When the surface of the metal foil is oxidized, an oxide film is formed on the surface of the metal foil. The thickness of the oxide film is preferably selected in the range of 0.01 to 30 μm.
[0022]
Moreover, it is preferable to further comprise the process of patterning the metal foil backed by the carrier film by etching before the process of transferring the metal foil.
[0023]
The present invention is also directed to a ceramic electronic component or a multilayer ceramic electronic component obtained by the manufacturing method as described above.
[0024]
DETAILED DESCRIPTION OF THE INVENTION
1 and 2 are cross-sectional views sequentially showing typical steps included in a method for manufacturing a multilayer ceramic electronic component according to an embodiment of the present invention.
[0025]
First, as shown in FIG. 1 (1), a metal foil 2 backed by a carrier film 1 is prepared.
[0026]
As the material of the carrier film 1 described above, a material that is flexible, has heat resistance that does not deform at a temperature of about 100 ° C., and can sufficiently withstand plating and vapor deposition is used. As an example, a carrier film 1 made of polyethylene terephthalate is advantageously used.
[0027]
The metal foil 2 is provided by a copper foil, for example. Such a metal foil 2 is preferably formed by plating.
[0028]
In addition, the metal foil 2 is coated with a resist on the metal foil 2 and exposed and developed based on photolithography in order to obtain a conductor film pattern required for the multilayer ceramic electronic component to be obtained. Then, patterning is performed by etching. The metal foil 2 shown in FIG. 1 (1) is in a state after such patterning.
[0029]
Next, as shown in FIG. 1 (2), the first surface 3 facing the outside of the metal foil 2 backed by the carrier film 1 is oxidized, whereby a first oxide film 4 is formed. The thickness of the first oxide film 4 is preferably in the range of 0.01 to 30 μm.
[0030]
In performing the above-described oxidation treatment, for example, a step of heat-treating the metal foil 2 in an adjusted atmosphere is performed. In this heat treatment for oxidation, the oxygen partial pressure that gives the atmosphere is changed, water vapor, ozone, or the like is introduced into the atmosphere, or the temperature and the treatment time applied in the heat treatment are changed as described above. The thickness of the first oxide film 4 can be adjusted. In addition, regarding the temperature of heat processing, it is preferable that it is 150 degrees C or less which does not produce a deformation | transformation of the carrier film 1 which consists of polyethylene terephthalate.
[0031]
With respect to the metal constituting the metal foil 2, for example, a metal that is passivated by oxidation such as aluminum, an extremely thin oxide film is formed on the surface, which makes it impossible for oxygen to diffuse into the interior, and oxidation occurs. Since it does not proceed, it is difficult to form an oxide film having a predetermined thickness.
[0032]
On the other hand, when the metal foil 2 is made of copper, for example, the copper oxide is not passive, but rather has a porous structure. By managing the conditions, the oxide film 4 having an arbitrary thickness can be easily formed. From this viewpoint, as a metal constituting the metal foil 2, in addition to copper, silver, palladium, nickel, molybdenum, tungsten, tin, or a metal containing these metals as a main component can be advantageously used.
[0033]
Next, as shown in FIG. 1 (3), a ceramic green sheet 5 is prepared, and the carrier film 1 to the ceramic green sheet 5 with the first surface 3 of the metal foil 2 facing the ceramic green sheet 5. The metal foil 2 is transferred onto 5.
[0034]
In the transfer described above, for example, hot stamping to which an appropriate pressure and temperature are applied is applied.
[0035]
Moreover, it is preferable that the ceramic green sheet 5 contains the low-temperature sintering ceramic material which can be baked at the temperature of 1000 degrees C or less, for example. This low-temperature sintered ceramic material contains a glass component that has an appropriate viscosity at the firing temperature. Such a glass component has good wettability with the metal oxide and dissolves the metal oxide. It is preferable that the solubility is in an appropriate range.
[0036]
Next, as shown in FIG. 2 (1), the second surface 6 facing the outside of the metal foil 2 transferred onto the ceramic green sheet 5 is oxidized, whereby a second oxide film 7 is formed. The The method and conditions for forming the second oxide film 7 can be substantially the same as those of the first oxide film 4 described above. The thickness of the second oxide film 7 is also preferably in the range of 0.01 to 30 μm.
[0037]
Next, as shown in FIG. 2 (2), a plurality of ceramic green sheets 5 are laminated, thereby producing a raw laminated body 8. In FIG. 2 (2), only a part of the raw laminated body 8 in the laminating direction is illustrated, but any of the surfaces where the metal foil 2 is in contact with the ceramic green sheet 5 is shown. , Provided by the oxide film 4 or 7.
[0038]
Next, the raw laminate 8 is pressed in the laminating direction while being heated, and then baked in a reducing atmosphere through a binder removal step.
[0039]
In this firing step, the glass component contained in the ceramic green sheet 5 is heated to be in a low viscosity state, penetrates into each of the oxide films 4 and 7 and spreads in the oxide films 4 and 7 based on the capillary phenomenon. .
[0040]
As described above, the glass component wet and spread in the oxide films 4 and 7 is anchored between the oxide and the ceramic particles while partially dissolving an oxide such as copper oxide constituting the oxide films 4 and 7. Form a structure. Further, when the glass component reaches each interface between the oxide films 4 and 7 and the other metal portions in the metal foil 2, a chemical bond is generated at these interfaces, and thereby the ceramic and metal on the ceramic green sheet 5 side are generated. The foil 2 is firmly joined.
[0041]
When copper is used as the metal constituting the metal foil 2, the oxide films 4 and 7 are mainly composed of Cu ₂ O, and called Cu—Cu—Cu—O—Cu—O—Si—O— at the above-described interface. Such chemical bonds are generated.
[0042]
Thus, the oxide films 4 and 7 play an important role in order to increase the bonding force between the ceramic layer obtained by firing the ceramic green sheet 5 and the metal foil 2. When such an oxide film is not formed, since the wettability between the metal such as copper and the glass component constituting the metal foil 2 is not good and the metal foil 2 is dense, the glass component is the metal foil. 2 does not penetrate.
[0043]
Moreover, it is preferable that each thickness of the oxide films 4 and 7 exists in the range of 0.01-30 micrometers as mentioned above. When the thickness of each of the oxide films 4 and 7 is reduced to less than 0.01 μm, substantially all the metal oxide such as copper oxide is dissolved in the glass component, and the interface between the oxide films 4 and 7 and the ceramic layer. The anchor structure may not be formed, or a chemical bond may not be generated at the interface between the oxide films 4 and 7 and the other metal portion in the metal foil 2. On the other hand, when oxide films 4 and 7 are thicker than 30 μm, the glass component does not penetrate into each of oxide films 4 and 7, and oxide films 4 and 7 are inherently weak in oxide films 4 and 7. The part may remain as it is.
[0044]
The embodiment described above relates to a method for manufacturing a multilayer ceramic electronic component, and is intended to form an internal conductor film with the metal foil 2. Therefore, the ceramic green sheet 5 is in contact with both the first and second surfaces 3 and 6 of the metal foil 2 and it is necessary to increase the bonding force with the ceramic portion with respect to the first and second surfaces 3 and 6. Therefore, the first and second oxide films 4 and 7 are formed along the first and second surfaces 3 and 6, respectively.
[0045]
However, when the metal foil is in contact with the ceramic portion only on one side, it is sufficient to form an oxide film along only one surface of the metal foil. That is, for a conductor film formed on the outer surface of the multilayer ceramic electronic component, or more generally, a conductor film formed on the outer surface of the ceramic body provided in the ceramic electronic component, these conductor films are used. It is sufficient to form an oxide film only on the side of the metal foil to be provided that contacts the ceramic portion.
[0046]
The above will be described with reference to FIG. 1 again. As shown in FIG. 1 (1), after preparing the metal foil 2 backed by the carrier film 1, as shown in FIG. 1 (2), The surface 3 facing the outside of the metal foil 2 backed by the carrier film 1 is oxidized to form an oxide film 4.
[0047]
Next, as shown in FIG. 1 (3), the carrier film 1 is placed on the raw ceramic molded body 5 with the oxidized surface 3 of the metal foil 2 facing the ceramic green sheet or the raw ceramic molded body 5. Then, the metal foil 2 is transferred.
[0048]
And the desired ceramic electronic component is obtained through the process of baking the raw ceramic molded body 5 to which the metal foil 2 is transferred as described above in a reducing atmosphere.
[0049]
In the embodiment described above, the step of patterning the metal foil 2 backed by the carrier film 1 by etching is applied to the first surface 3 of the metal foil 2 in order to give a desired pattern to the metal foil 2. 1 is performed before the step of forming the oxide film 4, but such a patterning step is performed before the step of transferring the metal foil 2 to the ceramic green sheet or the raw ceramic molded body 5. May be implemented. For example, such a patterning step may be performed after forming the first oxide film 4 or after forming the second oxide film 7.
[0050]
Further, after forming the metal foil 2 on the carrier film 1, the metal foil 2 is not patterned, but at the stage of forming the metal foil 2 on the carrier film 1, for example, by using a mask in advance. The formed metal foil 2 may be formed. Further, in the step of transferring the metal foil 2 to the ceramic green sheet or the raw ceramic molded body 5, only a predetermined portion of the metal foil 2 is selectively transferred so that the metal foil 2 is patterned. Also good.
[0051]
Below, the experiment example implemented in order to confirm the effect by this invention is demonstrated.
[0052]
[Experimental example]
A carrier film made of polyethylene terephthalate was prepared, and after applying a catalyst and activating treatment thereto, chemical plating was performed at a liquid temperature of 80 ° C. for 4 minutes to form a metal foil made of copper having a thickness of 5 μm. .
[0053]
Next, a resist was coated on the metal foil, exposure and development by photolithography were performed, etching was performed with dilute nitric acid for 2 seconds, and the metal foil was patterned.
[0054]
Next, the metal foil made of copper thus patterned was heat-treated at a temperature of 80 ° C. for 20 minutes in an air atmosphere while being lined with a carrier film. As a result, an oxide film having an average thickness of about 0.8 μm was formed on the surface facing the outside of the metal foil. The main component of this oxide film was Cu ₂ O, but metallic copper and CuO were also detected.
[0055]
Next, the metal foil was transferred from the carrier film onto the ceramic green sheet with the surface on which the metal foil oxide film was formed facing the ceramic green sheet. Here, a ceramic green sheet containing a low-temperature sintered ceramic material containing 50% by weight of alumina and 50% by weight of Al—Si—Ba—Sr—B—O-based glass was used. Further, hot stamping was applied during the transfer, and in this hot stamping, a pressure of 100 kg / cm ² and a temperature of 100 ° C. were applied for 10 seconds.
[0056]
Next, the surface facing the outside of the metal foil transferred onto the ceramic green sheet was oxidized under the same conditions as described above, and an oxide film was formed along this surface.
[0057]
Next, a plurality of ceramic green sheets having a metal foil forming an oxide film on each of the opposing surfaces as described above were laminated, and the resulting green laminate was obtained at a temperature of 80 ° C. and 1000 t / cm. Pressed at a pressure of ² for 45 seconds.
[0058]
Next, the green laminate after pressing was subjected to binder removal treatment, and then fired at a temperature of 950 ° C. in a reducing atmosphere to produce a multilayer ceramic substrate.
[0059]
With respect to the multilayer ceramic substrate according to the sample thus obtained, the bonding strength between the metal foil and the ceramic portion measured by a peel test was 1.9 kgf / cm ² .
[0060]
On the other hand, as a comparative example, in the multilayer ceramic substrate obtained through the same operation as described above, except that no oxide film is formed, the bonding strength between the metal foil and the ceramic portion is 0. It was only 4 kgf / cm ² .
[0061]
【The invention's effect】
As described above, according to the present invention, when a ceramic electronic component or a multilayer ceramic electronic component is manufactured, the metal foil is used as a conductor film, and the surface of the metal foil in contact with the ceramic portion is oxidized. Since the film is formed, the bonding strength between the ceramic portion and the metal foil can be increased.
[0062]
Further, according to the present invention, in the ceramic electronic component or the multilayer ceramic electronic component, since the conductive film is formed of the metal foil, the conductive film is made thinner and the high frequency characteristics are compared with the case where the conductive paste is used. Improvement and pattern miniaturization can be achieved.
[0063]
In the present invention, when at least one selected from silver, palladium, copper, nickel, molybdenum, tungsten and tin is used as the metal constituting the metal foil, the metal foil does not passivate by oxidation, and thus has a desired thickness. This oxide film can be easily formed.
[0064]
In the present invention, if the metal foil is formed by plating, the metal foil can be formed at a lower cost compared to other thin film processes such as sputtering.
[0065]
In the present invention, when the surface of the metal foil is oxidized, if the metal foil is heat-treated in a controlled atmosphere, the thickness of the oxide film formed on the surface of the metal foil can be easily controlled. it can.
[0066]
When the thickness of the oxide film described above is selected within the range of 0.01 to 30 μm, a strong bonding state can be more reliably obtained between the metal foil and the ceramic portion.
[0067]
In particular, according to the present invention, since the green ceramic compact or the ceramic green sheet comprises a glass component, the glass component penetrates the oxide film, the anchor structure and the chemical bonding by the glass component is formed, the ceramic part and the metal The bonding strength with the foil can be further increased.
[0068]
Also, in the present invention, if the metal foil backed by the carrier film is patterned by etching before the step of transferring the metal foil to a raw ceramic molded body or ceramic green sheet, the patterning is efficiently performed. In addition, a fine pattern can be easily given to the metal foil.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view schematically showing each step included in a method for manufacturing a multilayer ceramic electronic component according to an embodiment of the present invention.
2 is a cross-sectional view schematically showing each step performed subsequent to the step shown in FIG. 1. FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Carrier film 2 Metal foil 3 1st surface 4 1st oxide film 5 Ceramic green sheet or raw ceramic molded object 6 2nd surface 7 2nd oxide film 8 Raw laminated body

Claims (14)

Preparing a metal foil backed by a carrier film;
Oxidizing the surface facing the outside of the metal foil backed by the carrier film;
Transferring the metal foil from the carrier film onto the raw ceramic molded body with the oxidized surface of the metal foil facing the raw ceramic molded body;
Firing the raw ceramic molded body to which the metal foil has been transferred in a reducing atmosphere ,
The raw ceramic molded body contains a glass component,
Manufacturing method of ceramic electronic components.   The method for producing a ceramic electronic component according to claim 1, wherein the metal foil includes at least one selected from silver, palladium, copper, nickel, molybdenum, tungsten, and tin.   The method for producing a ceramic electronic component according to claim 1, wherein the step of preparing the metal foil backed by the carrier film comprises a step of forming the metal foil on the carrier film by plating.   The method of manufacturing a ceramic electronic component according to any one of claims 1 to 3, wherein the step of oxidizing the surface of the metal foil includes a step of heat-treating the metal foil in an adjusted atmosphere.   5. The thickness of the oxide film obtained by oxidizing the surface of the metal foil in the step of oxidizing the surface of the metal foil is selected in the range of 0.01 to 30 μm. Manufacturing method of ceramic electronic components. Wherein before the step of transferring the metal foil, further comprising the step of patterning the metal foil backed by the carrier film by etching, the production method of a ceramic electronic component according to any of claims 1 to 5. It claims 1 obtained by the manufacturing method according to any one of 6, the ceramic electronic component. Preparing a metal foil backed by a carrier film;
Oxidizing the first surface facing the outside of the metal foil backed by the carrier film;
Transferring the metal foil from the carrier film onto the ceramic green sheet with the first surface facing the ceramic green sheet;
Oxidizing the second surface facing the outside of the metal foil transferred onto the ceramic green sheet;
Laminating a plurality of ceramic green sheets to produce a raw laminate;
Firing the raw laminate in a reducing atmosphere ,
The ceramic green sheet includes a glass component,
Manufacturing method of multilayer ceramic electronic component. The method for producing a multilayer ceramic electronic component according to claim 8 , wherein the metal foil includes at least one selected from silver, palladium, copper, nickel, molybdenum, tungsten, and tin. The method for producing a multilayer ceramic electronic component according to claim 8 or 9 , wherein the step of preparing a metal foil backed by the carrier film comprises a step of forming the metal foil on the carrier film by plating. The multilayer ceramic electronic component according to any one of claims 8 to 10 , wherein each step of oxidizing the first and second surfaces of the metal foil includes a step of heat-treating the metal foil in a conditioned atmosphere. Manufacturing method. In each step of oxidizing the first and second surfaces of the metal foil, each thickness of the first and second oxide films obtained by oxidizing the first and second surfaces of the metal foil is 0 selected in the range of .01～30Myuemu, method for manufacturing a multilayer ceramic electronic component according to any of claims 8 to 11. Before the step of transferring the metal foil, the said metal foil backed by a carrier film, further comprising a step of patterning by etching, a method of manufacturing a multilayer ceramic electronic component according to any of claims 8 to 12 . It claims 8 to obtained by the production method according to any one of 13, the multilayer ceramic electronic component.

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