JP4493904B2 - Manufacturing method of zirconia setter - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention is a ceramic electronic device component (hereinafter referred to as “electronic device component”) represented by a capacitor, a piezoelectric element, a ferrite element, a high frequency ceramic substrate, a highly accurate metal system and ceramic component manufactured by injection molding, etc. The present invention relates to a method for producing a zirconia setter (hereinafter simply referred to as “setter” ) used when heat-treating or firing (hereinafter referred to as “baking or the like”).
[0002]
[Prior art]
In recent years, ceramic thin films with various properties have been developed and applied to a wide variety of ceramic electronic devices. However, when firing is performed in the manufacturing process of electronic device components, productivity is reduced. Therefore, a setter that can accommodate a plurality of electronic device components is used. Specifically, for example, based on a refractory material mainly composed of alumina or alumina-silica (mullite) having a particle size distribution ranging from several millimeters to several microns, a setter in which zirconia is thermally sprayed, A setter or the like in which the surface of alumina ceramic is coated with zirconia is used (see Patent Documents 1 and 2).
[0003]
By the way, with the recent improvement in the productivity of electronic device parts and the improvement in product quality, further improvements to the firing process of electronic device parts are required. There are similar problems in heat treatment of high-precision metal systems and ceramic parts manufactured by injection molding.
On the other hand, the applicants have already been able to more efficiently remove a large amount of organic binder added in the molding process of the electronic device component, and in addition, firing and the like while keeping the coexisting electrode material stable. As a setter that can be performed, a ceramic setter having a plurality of fine linear through holes containing 75% by weight of alumina has been proposed. By using such a setter, even when the loading amount of the electronic device component is increased, high uniform air permeability is realized at the time of heat treatment such as firing, and uniform temperature distribution and maintenance of atmospheric gas uniformity can be achieved. As a result, the quality of the manufactured electronic device component is maintained uniformly, and an electronic device component that is a highly functional material is obtained. Furthermore, as a method for preventing the electronic device component from reacting with the setter, it has been proposed to coat the surface of the setter with zirconia (see Patent Document 3).
[0004]
Zirconia is considered to be useful as a material for forming a setter because it hardly reacts with electronic device components to be mounted as compared with other materials. However, when a setter is formed only with zirconia, the density is higher and heavier than a material such as alumina, so that it is not easy to handle, and at the same time, the cost is higher than that of an alumina setter, which is economical. It will be inferior. In addition, zirconia has a low thermal conductivity compared to materials such as alumina, and depending on the firing conditions, there is a problem that is unique to zirconia setters, in which a temperature difference occurs on the setter, resulting in firing unevenness in the fired product. . For this, it has been proposed that the thickness of the setter made of only zirconia is as thin as 0.2 to 2 mm, an independent through hole is formed on the surface, and the theoretical density of the forming material is 95% or more. (See Patent Document 4).
[0005]
[Patent Document 1]
Japanese Patent Laid-Open No. 61-24225 [Patent Document 2]
Japanese Patent Laid-Open No. 3-1090 [Patent Document 3]
JP 2002-145672 A [Patent Document 4]
Japanese Patent Laid-Open No. 11-79853
[Problems to be solved by the invention]
However, according to the study by the present inventors, in the case of the setter coated with zirconia described in Patent Document 3, the alumina setter is manufactured, and then the surface is coated with zirconia. There was a problem that the process was complicated. Further, Patent Document 4 describes a setter made of only zirconia and a manufacturing method thereof. In this case, the manufacturing method is to form a sheet-like molded body by a slurry casting method or a doctor blade method. The molded body is then punched, and then fired to form a setter. The production method is very complicated, and in this method, a molded body thicker than 2 mm cannot be obtained. On the other hand, if the thickness is less than 0.2 mm, the molded body is easily broken during or after the punching process, and a setter thinner than this cannot be formed. In particular, when the through hole has a high hole area ratio, this tendency is strong, even if it is thicker than 0.2 mm, the mechanical strength is not sufficient, and further, the molded body is fired after punching. There is also a problem that warping sometimes occurs, and the above method cannot obtain a zirconia setter with a high yield.
[0007]
In addition, since zirconia lacks thermal stability, there has been a problem that cracking occurs and durability is inferior when a setter consisting of only zirconia is repeatedly used for heating and firing. From these facts, the present inventors can perform heating and firing in a good state while being a setter using a zirconia material that does not react with the mounted electronic device component, and is durable. It has been recognized that it is necessary to develop a zirconia setter having excellent properties, and further to develop a production method capable of obtaining such a setter easily, with good yield and economically.
[0008]
Accordingly, the object of the present invention is to solve the above-mentioned problems of the prior art, have sufficient strength, do not react with the mounted electronic device components, and are made of zirconia while maintaining a uniform temperature. An object of the present invention is to provide a zirconia setter excellent in performance and economy that achieves distribution, does not cause uneven baking in the obtained fired product, and exhibits high durability even when heating or firing treatment is repeated.
Another object of the present invention is to provide a method for producing such an excellent setter easily and economically with good yield.
Furthermore, an object of the present invention is to provide an excellent setter as described above and a method for manufacturing the same, thereby achieving an improvement in the quality and productivity of electronic device parts manufactured using the setter. As a result, it contributes to improving the quality of ceramic-based electronic device products and the like using these components and achieving economic efficiency.
[0009]
[Means for Solving the Problems]
The above object is achieved by the present invention described below .
[0010]
The present invention is a method for producing a zirconia setter made of a zirconia sintered body and having a thickness of a portion on which the object to be fired is loaded is thinner than 0.2 mm, and is stabilized by Y ₂ O ₃ , CaO or MgO After adding at least an organic compound to the obtained zirconia powder and imparting plasticity to the powder, the plasticized powder is molded into a rod-shaped molded product by extrusion molding or injection molding, and the molded product is dried and then dried. The molded product is fired at a temperature of 1400 to 1700 ° C., and the obtained fired product is cut horizontally using a cutting machine so that the thickness of the portion on which the fired product is placed is thinner than 0.2 mm. a method for producing a zirconia setter, which comprises forming a plurality of plate-shaped setter Te.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in more detail with reference to preferred embodiments.
First, the electronic device components mounted on the setter of the present invention have various characteristics used for forming various ceramic-based electronic devices such as capacitors, piezoelectric elements, ferrite elements, and high-frequency ceramics. It is a ceramic member such as a ceramic thin film (tape or sheet) or bulk (having a certain size). The setter of the present invention is used in the heat treatment and firing process performed when these members are manufactured, and in particular, the fine functional materials made of ceramics such as electronic device parts as described above It can be preferably used over a wide range. Since the above-described electronic device components are required to have high functionality, it is particularly required that reliable, homogeneous and high-quality products be stably supplied.
[0012]
Therefore, it is required that the processing in the manufacturing process, such as firing, be performed uniformly without causing uneven firing, and at the same time, impurities are mixed from the setter into these members at the stage of firing, etc. Of course, it is necessary to completely prevent the member from reacting with the setter material and to avoid the adverse effects that may arise from the use of the setter. On the other hand, in various fields using electronic device parts manufactured using setters, it is possible to improve the productivity of products using electronic device parts, that is, to reduce manufacturing costs and to be more economical. Although obtaining a product is an urgent need, cost reduction is also required for various members used for manufacturing, such as setters. Therefore, there is a setter that does not reduce the quality as a setter, is inexpensive, has excellent functionality and ease of use, and enables efficient and uniform heating and firing of the mounted electronic device parts. Long-awaited.
[0013]
On the other hand, in the present invention, while the zirconia having a high melting point and little reaction with other materials is used as a setter forming material, the thickness of the portion on which the object to be fired is loaded is less than 0.2 mm. Since it is thin, it can be processed under uniform conditions such as firing, and when used in the firing process of electronic device parts, it does not cause uneven firing on the fired product. It is possible to provide a setter that can achieve high durability even when the treatment is repeated. Hereinafter, the configuration of the setter of the present invention will be described in detail.
[0014]
As described above, the setter of the present invention is composed of a zirconia sintered body. As the zirconia, it is preferable to use one of partially stabilized zirconia and stabilized zirconia described below. Partially stabilized or stabilized zirconia is obtained by adding CaO, MgO, Y ₂ O ₃ or the like to pure zirconia. There are three types of pure zirconia: monoclinic, tetragonal, and cubic, and they have phase transition points near 1100 ° C and 2370 ° C. Therefore, in the transition from tetragonal to monoclinic during cooling, It is known to involve volume expansion. For this reason, when pure zirconia is used, cracks may occur due to the volume expansion that occurs during firing, but if partially stabilized zirconia or stabilized zirconia to which an additive as described above is added is used, Generation of cracks can be effectively prevented.
[0015]
According to the study by the present inventors, in particular, when stabilized zirconia is used, as a setter for mounting electronic device components, even when repeated heating or baking treatment is used, cracking does not occur, and high durability It was found to show sex. In Patent Document 4 described above, it is considered preferable to use partially stabilized zirconia having a molar ratio of Y ₂ O ₃ / ZrO ₂ of 1.5 / 98.5 to 6.0 / 94.0. If it exceeds 0 / 94.0, the mechanical strength becomes weaker as the thickness of the setter becomes thinner, and it cannot be used repeatedly. However, according to the manufacturing method of the present invention, which will be described later, a zirconia setter that is thinner than 0.2 mm and has sufficient strength even when a plurality of through holes are provided can be easily obtained. Further, for example, even when stabilized zirconia having a molar ratio of Y ₂ O ₃ / ZrO ₂ of 8.0 / 92.0 is used, the thickness of the portion on which the object to be fired is similarly set to 0. Although it is thinner than 2 mm, a setter having sufficient mechanical strength can be obtained. According to the study by the present inventors, in particular, when stabilized zirconia is used as a main raw material, a higher zirconia setter that achieves higher thermal stability and is more durable when repeated heating and firing treatments. I found out that In the above description, the case where Y ₂ O ₃ is added and stabilized is described as an example. However, the case where it is stabilized with CaO or MgO is the same as described above.
[0016]
The setter of the present invention may be a plate as shown in FIG. 1 or a tray having at least a bottom plate and a side wall (not shown). Moreover, after forming in plate shape, the plate-shaped thing with the convex part which provided the convex member of the arbitrary shapes which function as a spacer on the at least one surface of a plate etc. may be sufficient (refer FIG. 2). In this way, since setters can be used in a stacked manner, firing of electronic device components can be performed intensively. However, it is not limited to this, and even if it is a plate-shaped setter as shown in FIG. 1, if a dedicated stand on which the setter can be placed collectively is used, an intensive baking process is performed. be able to. Furthermore, the setter of the present invention may have a plurality of through holes as shown in FIG. 3, for example, or may not have a through hole as shown in FIG. The shape of the through hole is not particularly limited, but it is preferable to provide a fine through hole (for example, 0.15 to 1 mm) over substantially the entire surface of the portion on which the object to be fired is stacked. However, since the setter of the present invention is thinner than 0.2 mm, a uniform temperature distribution can be achieved without providing a through-hole, so that the fired product can be fired without causing uneven firing. It is possible to do.
[0017]
However, the present invention is not limited to these, and any shape may be employed as long as the electronic device component can be loaded and held on the portion of the setter on which the object to be fired is loaded. The size of the setter is also not particularly limited, depending on the size and number of electronic device components mounted inside, and further appropriately determined in consideration of the shape of the dedicated stand for mounting the setter described above. Good.
[0018]
Below, the manufacturing method suitable for manufacturing the zirconia setter of this invention of the form which has multiple through-holes is demonstrated.
First, as the forming material of the setter, for example, 8 mol Y ₂ O ₃ stabilized zirconia, CaO stabilized zirconia, MgO stabilized zirconia, manufactured by Daiichi Elemental Chemical Co., Ltd. or Tosoh Corporation, or Partially stabilized zirconia such as 3 mol Y ₂ O ₃ stabilized zirconia can be used. As the particle size of these powder materials, those having an average particle size of 0.3 to 3 μm are preferably used.
[0019]
Next, an organic compound is added to the powder material as mentioned above to impart plasticity to the powder. The addition ratio of the organic compound used at this time is preferably 3 to 10% on a mass basis with respect to the zirconia powder material as described above. As the organic compound used at this time, specifically, the following compounds can be used. However, the above-listed zirconia powder materials are imparted with appropriate plasticity, thereby forming a rod-shaped molded product. Any material can be used as long as it can be formed.
[0020]
Specifically, as an organic compound that can be used to impart plasticity to the zirconia powder material, the weight average molecular weight is in the range of 400 to 6,000, and it melts during heating and exhibits an appropriate viscosity. -It is preferable to use an organic compound having such characteristics that it does not remain after firing. This includes polyesters and cellulose derivatives containing many oxygen atoms in the molecule, as well as any amount of ethylene oxide copolymerized with polyethylene oxide, polypropylene oxide, or propylene oxide having an appropriate degree of polymerization. It is preferable to use a polyether.
[0021]
Polyethers (industrial polyglycols) are generally used for nonionic surfactants, lubricants, hydraulic fluids, etc. For example, propylene oxide is mixed with an arbitrary amount of ethylene oxide to produce ethylene. It can be synthesized by copolymerization using a dihydric alcohol such as glycol or propylene glycol or a trihydric alcohol such as glycerin or pentaerythritol as an initiator. Such polyethers can be obtained by appropriately selecting these synthetic materials, so that those having a wide variety of physical properties can be obtained. Therefore, a specific polyether having good physical properties suitable for the purpose of use of the setter is selected. It can be appropriately selected and used. Accordingly, it is particularly preferable to use a polyether having a weight average molecular weight in the range of 400 to 6,000 as the organic compound for imparting plasticity to the raw material powder. If it does in this way, since the molding which has a through-hole obtained as follows has a moderate intensity | strength of the grade which can hold | maintain the shape, the subsequent baking operation can be performed favorably.
[0022]
As a rod-shaped molded product formed using a plasticized zirconia material, it is sufficient to load electronic device components when a setter is formed by cutting to a thickness smaller than 0.2 mm. Any shape may be used as long as a proper loading portion is formed. Furthermore, what is necessary is just to determine according to the shape of the exclusive stand for mounting an above-described setter. For example, the cross-sectional area may be any shape such as a circle, an ellipse, a triangle, a polygon such as a square, a pentagon, or the like. The manufacturing method is not limited, but the material is sufficiently filled so that there is no filling of the zirconia material, resulting in a cavity or the like, and no defective product is generated when the setter is formed. In order to form a molded product or to form a through hole having a desired shape in a setter with good reproducibility, it is preferable to form a rod-shaped molded product by extrusion molding or injection molding. Hereinafter, this method will be described.
[0023]
For example, a rod-shaped molded product by extrusion molding can be easily obtained by the following procedure. First, polyether having an appropriate molecular weight within the above-described range is added to zirconia powder, and sufficiently mixed and kneaded by an extrusion molding machine to impart plasticity. If the kneaded product thus obtained is extruded through a die with an extrusion molding machine, a rod-shaped molded product can be easily obtained. By appropriately selecting the shape of the die used at this time, a molded product having a desired cross-sectional shape such as a circle, an ellipse, or various squares can be obtained. FIG. 4 is a perspective view of the block-shaped molded product obtained as described above.
[0024]
Further, for example, in order to manufacture a setter having a plurality of through holes having a desired shape, when a die is selected, a molded product having a plurality of linear through holes having openings having a desired shape is obtained. Extrusion molding may be performed using a die as described above. For example, a block-like molded product having a plurality of linear through-holes having a circular cross-section and an opening shape as shown in FIG. 5 may be formed. In this case, the circular shape of the cross section and the opening may be, for example, about 0.15 to 1.0 mm, more preferably about 0.3 to 0.5 mm. Of course, the cross-sectional shape of the through hole is not limited to a circle, and may be various shapes such as an ellipse and a polygon. Further, the plurality of through holes may be the same as shown in FIG. 5, or when cut and setters are used, for example, the opening diameters of the central hole and the peripheral hole are different. It may be uniform. FIG. 5A is a perspective view of a block-shaped molded product, and FIG. 5B is a schematic perspective view when cut at positions A and B. FIG. 3 in FIG. 5 shows a linear through-hole.
[0025]
As a method for producing the setter of the present invention according to another embodiment, a pore forming agent is added to zirconia powder having plasticity at the time of extrusion molding, so that it is continuously applied to a zirconia fired body in a subsequent firing step by a conventionally known method. Or you may use the rod-shaped molding in which the discontinuous hole was formed.
[0026]
In the present invention, the molded product obtained as described above is preferably dried at a temperature of about 30 to 80 ° C, and the dried molded product is preferably fired at 1400 to 1700 ° C. The drying time may be about 5 to 12 hours, though it depends on the organic compound used and the size of the molded product.
[0027]
Finally, the fired product obtained as described above is cut into the setter by the following method. As a cutting machine used at this time, any of an inner circumference slicer, a multi-wire saw, and a band saw, more preferably, an inner circumference slicer or a multi-wire saw is used. For example, an inner circumference slicer or a multi-wire saw is used for precision cutting when a silicon wafer is cut out from an ingot, and is particularly effective for producing a thin setter. If an inner peripheral slicer is used, a block-shaped molded product (baked product) as shown in FIGS. 4 and 5 is horizontally cut at the position of the broken line indicated by 5 in these drawings. A plate-like setter thinner than 2 mm can be easily produced. However, the setter of the present invention is not limited to a plate shape, and by using the above-mentioned cutting machine as appropriate, a tray-like one having a thickness of a portion on which the object to be fired is thinner than 0.2 mm is cut out. Is also possible.
[0028]
【Example】
Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples.
<Example 1>
In this example, 8 mol Y ₂ O ₃ stabilized zirconia powder having an average particle size of 0.5 μm was used as the forming material. Further, as the organic compound to be contained in the powder, a polyether having a weight average molecular weight of 3,000 obtained by mixing propylene oxide with an arbitrary amount of ethylene oxide and copolymerizing using glycerin as an initiator was used. Then, the copolymer was added to the zirconia powder at a ratio of 5% by mass and mixed and kneaded with an extrusion molding machine to impart plasticity. Using the kneaded material thus obtained, a prismatic shaped product having no holes as shown in FIG. 4 was formed by an extrusion molding machine. This was dried at 50 ° C. for 12 hours, then heated to 1550 ° C. under the condition of 60 ° C./hour, and baked at that temperature for 120 minutes to prepare a zirconia fired body. When the size of the obtained columnar fired body was measured, it was approximately 120 × 120 × 40 mm.
[0029]
Next, the zirconia fired body obtained above was cut horizontally using an inner slicer [trade name: SL-LM-434D, manufactured by Tokyo Seimitsu Co., Ltd.], and the thickness was 0.19 mm (A -1), 0.17 mm (B-1), 0.15 mm (C-1), and 0.13 mm (D-1), 4 types of plate-shaped setters without holes were obtained.
[0030]
<Example 2>
In this example, a columnar molded product similar to that in Example 1 was used except that a plurality of linear through holes having a cross-sectional shape of 0.5 mmφ were formed by changing the die used at the time of extrusion molding. The setter was obtained in the same manner as in Example 1 in the subsequent firing and cutting steps. The obtained setter is the same as that of Example 1 except that it has a plurality of through holes. 0.19 mm (A-2), 0.17 mm (B-2), 0.15 mm (C-2) ) A plate-like setter having through-holes of four types of thickness of 0.13 mm (D-2).
[0031]
[Evaluation]
Using the eight types of setters obtained in Examples 1 and 2 above, each setter was loaded with the same amount of barium titanate-based ceramic molded body formed into a tape shape as a member for an electronic device. The baking process was performed. The temperature was raised at 30 ° C./hour and baked at 1150 ° C. for 120 minutes. And it was investigated about the case where each setter mentioned above was used, whether the baking unevenness generate | occur | produced in the obtained baked product. As a result, it was confirmed that a fired product in a good state with no baking unevenness was obtained with all setters.
[0032]
<Comparative example>
For comparison, except for setting the thickness of the setter to 0.2 mm, 0.5 mm, and 0.8 mm, the occurrence of baking unevenness was examined for the fired product in the same manner as in Example 1. Generation | occurrence | production of the baking unevenness was recognized and generation | occurrence | production of the baking unevenness was recognized clearly in the setter of the thickness of 0.5 and 0.8 mm.
[0033]
【The invention's effect】
As described above, according to the present invention, when used in a heat treatment or firing process of an electronic device component, it does not react with the object to be fired, does not cause uneven firing on the fired object, A setter having sufficient mechanical strength and excellent durability in repeated use is provided. Moreover, according to this invention, the manufacturing method of the zirconia setter which can manufacture the above-mentioned outstanding setter simply and economically is provided. Furthermore, according to the present invention, by providing a setter having the above-described excellent function at a low cost, it is possible to stably obtain a high-quality electronic device component at a low cost with high productivity. This contributes to improving the quality and productivity of ceramic electronic device products using electronic device parts.
[Brief description of the drawings]
FIG. 1 is a schematic perspective view of an example of a plate-like setter of the present invention.
FIG. 2 is a schematic perspective view of another example of a plate-like setter of the present invention.
FIG. 3 is a schematic perspective view of another example of a plate-like setter of the present invention.
FIG. 4 is a view showing a zirconia fired body used when producing the setter of the present invention.
FIG. 5 is a view showing another form of a zirconia fired body used when producing the setter of the present invention.
[Explanation of symbols]
1: setter 2: fired body 3: through-hole 4: convex member 5: line to be cut

Claims (2)

Made of zirconia sintered body, and the thickness of the portion Noseki to be baked product a thin method for producing a zirconia setter than 0.2 mm, Y ₂ O _3, zirconia powder stabilized with CaO or MgO After adding at least an organic compound to impart plasticity to the powder, the plasticized powder is molded into a rod-shaped molded product by extrusion molding or injection molding, and after drying the molded product, 1400 is obtained as a dried molded product. After baking at a temperature of ˜1700 ° C., the resulting fired product is cut horizontally using a cutting machine so that the thickness of the part on which the fired product is placed is thinner than 0.2 mm. method for producing a zirconia setter, characterized in that forming a plurality of setters. Method for producing a zirconia setter according to claim 1 molded rod-like, in which the extruded direction in a plurality of linear through-hole is provided.

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