JP2005331185A - Cover made from ceramics for use in setter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a novel technique which can realize uniform and good firing or the like when microminiature parts such as a multilayer ceramic capacitor are manufactured, additionally, with significantly improved yield as compared with conventional techniques, and can provide a product excellent in economical efficiency. <P>SOLUTION: A ceramics cover to be used, in a heat treatment step or firing step to be carried out when microminiature parts are manufactured, in the state of covering a object to be fired on a setter, comprising a plate part comprising a ceramics sintered body having a flat surface having a plurality of through holes provided therein and a convex part comprising a ceramics sintered compact provided near the outer periphery of either surface of the plate part, wherein, when arranged on the setter, a gap having substantially the same interval is formed between the flat surface of the plate part and a surface on which the object to be fired is loaded. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  In the present invention, in particular, when manufacturing ultra-small parts such as ultra-small ceramic-based electronic device parts, the object to be fired is placed on a setter and subjected to heat treatment or firing (hereinafter referred to as “firing etc.”). Furthermore, the present invention relates to a ceramic cover used by covering a fired object placed on a setter.

  In recent years, electronic device parts such as multilayer ceramic capacitors have been developed one after another. However, the achievement of miniaturization and high performance has been remarkable, for example, a low profile with a large capacity and a height of several millimeters or less. There is provided a multilayer ceramic capacitor which is a mold and can be used even in a harsh environment (especially high temperature). Such a multilayer ceramic capacitor is manufactured, for example, by alternately laminating thin-film ceramic dielectrics and metal internal electrodes and firing them in an electric furnace. Since these electronic device components are required to be supplied with a very high-performance product stably, great care is taken in the production thereof. On the other hand, the achievement of the reduction in the manufacturing cost of such electronic device parts is directly linked to the reduction in the cost of various precision machinery and equipment using the above-mentioned parts such as the multilayer ceramic capacitor. It is often desired to provide stable and high-quality electronic device components.

  Here, in a process such as firing when manufacturing the electronic device component as described above, a holder for the object to be fired called a setter is used, and a number of objects to be fired are simultaneously heat-treated. . In particular, it is indispensable to use a setter in the manufacture of minute parts. And, as a setter used for manufacturing electronic device parts made of ceramics that require high quality, a ceramic setter that has excellent heat resistance and does not cause contamination or reaction with the setter material is used. It has been. Specifically, for example, there are setters based on a refractory material mainly composed of alumina or alumina-silica (mullite), which is sprayed with zirconia, or a setter whose surface is coated with zirconia on an alumina ceramic. Used (see Patent Documents 1 and 2).

  Applicants have been able to more efficiently remove organic binders used in the molding process of electronic device parts so far in order to improve the productivity of electronic device parts and the quality of products in recent years. In addition, a ceramic setter having a plurality of fine linear through-holes having an opening diameter in the range of 0.3 to 1 mm, which can be fired in a state where the coexisting electrode material is kept stable, is provided. It has been proposed (see Patent Document 3). By using such a setter, even when the loading amount of the electronic device parts is increased, high uniform air permeability during firing is realized, and uniform temperature distribution and maintenance of the 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.

Japanese Patent Laid-Open No. 61-24225 Japanese Patent Laid-Open No. 3-1090 JP 2002-145672 A

  However, as described above, downsizing of electronic device parts such as multilayer ceramic capacitors has progressed from mm units to hundreds of μm units, and further to several μm units. For this reason, a problem that cannot be dealt with by a conventional setter alone has arisen. A setter having a through-hole as described above enables firing under uniform conditions for a plurality of objects to be fired on the setter, and can provide a stable quality product. In order to form a uniform through-hole in a setter made of a ceramic sintered body, it has an opening of a certain size in manufacturing. For this reason, if the material to be fired loaded on the setter is too small, such as the above-mentioned multilayer ceramic capacitor, the material to be fired may slip through these holes, resulting in a decrease in product yield. Happens. Therefore, a setter made of a ceramic plate not provided with a through hole is used for ultra-compact parts.

  According to the study by the present inventors, even if a ceramic plate without a through hole is used, it is possible to perform a uniform heat treatment on a plurality of parts if a thin plate is used. In the case of ultra-compact, it has been found that there are other problems as follows. That is, in the firing process when manufacturing electronic device parts, etc., the temperature inside the furnace is raised to several hundred to 1,000 degrees or more, but in that case the convection of heat generated in the furnace, and further the temperature inside the furnace is made uniform Because of the flow of hot gas that is forcibly sent, the ultra-small fired object placed on the setter rises and disappears from the setter, or hot gas etc. stays and all the objects to be processed A uniform heat treatment may not be performed on an object, resulting in a decrease in product yield of electronic device parts and the like.

  Accordingly, the object of the present invention is to solve the above-mentioned problems of the prior art and perform firing and the like performed in the case of manufacturing a micro component such as a multilayer ceramic capacitor in a uniform and good state and with a high yield. The object is to provide a new technology that makes it possible to obtain a product with excellent properties. Furthermore, an object of the present invention is to provide a ceramic cover used together with a setter in a firing process or the like that can obtain the above-described effects, thereby improving the quality and productivity of a micro component manufactured using the cover. The object is to contribute to the improvement of the quality of ceramic-based electronic device products using these micro components and the achievement of economy.

  The above object is achieved by the present invention described below. That is, the present invention is a ceramic cover used in a state of covering a fired object on a setter in a heat treatment process or a firing process performed when manufacturing a micro component, and includes a plurality of through holes. A plate portion made of a ceramic sintered body having a flat surface provided with a convex portion made of a ceramic sintered body provided near the outer periphery of one surface of the plate portion, and disposed on a setter. In this case, the convex portion is configured so that a gap having substantially the same interval is formed between the flat surface of the plate portion and the surface on which the firing object of the setter is stacked. This is a ceramic cover.

  ADVANTAGE OF THE INVENTION According to this invention, the ceramic cover which can perform baking etc. performed when manufacturing micro components, such as a multilayer ceramic capacitor, in a uniform and favorable state and also with a sufficient yield is provided. Furthermore, according to the present invention, by using such an excellent ceramic cover, the quality and productivity of the micro component can be improved, and the economy of the micro component can be improved. Thus, it is possible to contribute to the improvement of the quality of ceramic electronic device products in which these ultra-small parts are used and the achievement of economic efficiency.

  Hereinafter, the present invention will be described in more detail with reference to preferred embodiments. A ceramic cover according to the present invention (hereinafter simply referred to as a cover) is used in a heat treatment step or a firing step performed when manufacturing a microminiature component. As shown in FIG. It comprises a plate portion 2 having a flat surface and a convex portion 1 provided in the vicinity of the outer periphery of one surface of the plate portion 2, and these plate portion 2 and the convex portion 1 are made of a ceramic sintered body. This is the basic configuration. Then, when the cover according to the present invention is placed on the surface of the setter S to be fired, the flat surface of the plate portion 2 and the fired material B of the setter S are stacked by the convex portion 1. It is characterized in that a gap 3 having substantially the same interval is formed between the surface to be formed (see FIG. 1B).

  Since the cover according to the present invention has the above structure, when it is used, as shown in FIG. 1 (a), when it is arranged in a state of covering the ultra-small fired object B on the setter S, As shown in the partial enlarged view of FIG. 1B, a narrow gap 3 having substantially the same interval is formed between the plate portion 2 and the loading surface of the setter S, and the gap 3 is formed in the gap 3 portion. It will be in the state where ultra-small to-be-fired B was stored. And although baking etc. are carried out in this state, since a plurality of through holes 5 are provided in the plate portion 2 of the cover according to the present invention, as shown in the partially enlarged view of FIG. The hot gas flows freely through the narrow gap 3 so that the gas does not stay, and uniform firing without thermal segregation is performed on all the objects to be fired B. Hereinafter, the board part 2 and the convex part 1 which comprise the cover concerning this invention are demonstrated in detail.

  First, the plate part 2 of the cover concerning this invention is demonstrated with reference to figures. FIG. 2 is a schematic view of a cover according to the present invention. FIG. 2 (a) is a view from the surface side of the setter on which the object to be fired is placed when the cover is placed on the setter and put into use. FIG. 2B is a front view thereof, and FIG. 2C is a perspective view thereof.

In the example shown in FIG. 2, the flat surface of the plate portion 2 has a square shape, and three convex portions 1 are provided in the vicinity of the outer periphery of the plate portion. In the present invention, the shape of the plate portion 2 is not limited to the illustrated square, and when a cover is placed on a setter, a plurality of objects to be fired placed on the setter are covered with a flat surface constituting the plate portion 2. Any shape may be used as long as the narrow gap 3 having substantially the same interval is formed between the plate portion 2 and the setter. Therefore, it is preferable that the shape of the plate portion 2 is an appropriate shape according to the shape of the setter. For example, when it is arranged on a setter, if the shape of the setter is such that it can cover most of the portion on which the object to be fired is placed, for example, 80% or more, and further 90% or more, firing and the like can be performed more efficiently. can do. As a concrete thing, the thing whose plane area of a board part is about 50-250 cm < ² > is mentioned.

  One of the features of the cover according to the present invention is that a plurality of through holes 5 as described below are provided in the plate portion 2 as described above (see FIGS. 1B and 4B). ). Since the cover according to the present invention is provided with a plurality of through holes in the plate portion 2, by using this, it is possible to effectively prevent the disappearance of the ultra-small fired object during the process such as firing. It is possible to effectively prevent the occurrence of thermal segregation in the plurality of fired products obtained due to the volatilization gas or the hot gas remaining around the fired product. As a result, it is possible to significantly improve the product yield.

  The plurality of through holes 5 having substantially the same shape provided in the flat surface portion of the plate portion 2 allow hot gas to easily flow between the through holes 5, and the ultra-small to-be-fired object is heated. In order to prevent the gas from soaking up from the setter with gas, it is preferable to configure the size of the opening so that the longest portion is 3.0 mm or less. If the through hole is larger than 3.0 mm, the material to be fired may slip through the through hole depending on the size of the material to be fired.

  The shape of the through hole is not particularly limited, and may be any shape such as a square or a circle. For example, when the through hole has a square shape as shown in FIG. 4 (b), the area of the surrounding part that forms the opening can be reduced, so the cover is placed on the setter. Even so, the presence of the through-holes allows the volatilized gas from the object to be fired and the hot gas forced into the furnace to circulate well without staying on the setter. Furthermore, when the longest portion is 3.0 mm or less and the opening shape of the through-hole is a square, even if the ultra-small fired object is swollen from the setter, the fired object enters the hole, Since it does not easily slip through the hole, the yield of the product can be improved by using the cover. As described above, the cover according to the present invention requires that the circulation of the hot gas and the like be performed satisfactorily in a state in which the cover is disposed. For this purpose, the plate portion that hinders the circulation of the gas It is preferable that the area of the peripheral portion forming the opening portion of the through hole provided in is made as small as possible. Specifically, since it is made of ceramics, from the viewpoint of manufacturing difficulty, product strength, etc., the interval between adjacent through holes is set to about 0.1 to 0.5 mm, and a plurality of through holes It is preferable to provide a hole.

  The thickness of the plate part 2 constituting the cover according to the present invention is preferably thinner from the viewpoint of thermal efficiency and gas flow, and specifically, 2.0 mm or less, preferably 1.0 mm or less. Since the cover according to the present invention is made of ceramics, it depends on the ceramic material to be used. However, in view of difficulties in manufacturing, product strength, and the like, more specifically, 0.2 mm to 1.0 mm. It is preferable to set it as thickness.

  Next, the convex part 1 which consists of a ceramic sintered compact provided in the outer periphery vicinity of one surface of the board part 2 which has the above several through-holes 5 is demonstrated (refer FIG. 2). The convex part 1 which comprises the cover concerning this invention is substantially the same between the flat surface of an above-described board part, and the surface where the to-be-baked material of a setter is loaded, when a cover is arrange | positioned on a setter. This is for the purpose of forming a gap having an interval of.

  As a preferred embodiment of the cover according to the present invention, convex portions are provided at three locations near the outer periphery of one surface of the plate portion 2, and the shape of the convex portion 1 is changed between the flat surface of the plate portion 2 and the setter S. The gap 3 having substantially the same interval formed by the loading surface is 3.0 mm or less and, depending on the size of the object to be baked, has a narrow interval of 1.0 mm or less. Is mentioned. In other words, the gap 3 formed between the setter S and the flat surface of the plate portion 2 is provided so that the object to be fired on the setter is not lost by the flow of hot gas or the like, and good firing or the like is realized. It is preferable that the flow of hot gas or the like is not disturbed as much as possible. For this purpose, as shown in FIG. 2, the shape of the convex portion 1 that partially closes the gap 3 is made so that the gap 3 has a narrow interval, and the portion occupied by the convex portion in the gap 3 is as small as possible. In order to reduce the height, the height is lowered, and the portion in contact with the setter and the plate portion is made as narrow as possible.

  By making the shape of the convex portion 1 as described above, the gap 3 formed by the plate portion 2 and the loading surface of the setter S becomes very narrow. Even if it soars from above S, it is effectively prevented that the object B is blown out of the setter from the gap 3 or spills off from the setter. As a result, in combination with the presence of the plurality of through holes provided in the plate portion 2 described above, by using the cover according to the present invention, it is possible to uniformly and efficiently perform firing on the object to be fired, Product yield can be significantly improved.

  In the example of the cover according to the present invention shown in FIG. 2, the convex portions 1 having the structure described above are provided at three locations near the outer periphery of one surface of the square plate portion 2. Is not limited to this, as long as the gap 3 having substantially the same interval can be formed between the flat surface of the plate portion 2 and the surface of the setter to be fired. Any of these may be used. However, in order to achieve both the stability of the cover when the cover is placed on the setter and the good circulation of hot gas, etc., as described above, the convexity that blocks the circulation of hot gas, etc. It is preferable to reduce the proportion of the portion 1 in the gap 3 as much as possible. For this purpose, it is effective to provide the small convex portions 1 at three locations near the outer periphery of the plate portion 2. In order to further improve the stability when the cover is arranged on the setter, the positional relationship of the convex portions provided at the three locations is such that the center of gravity of the triangle formed by connecting the convex portions is near the center of the plate portion. It is recommended that Specifically, for example, at a position as shown in FIG. 3, a rectangular column shape (see FIGS. 2 and 3 (a) to (c)) or a cylindrical shape (see FIGS. 3 (d) to (f)). If the convex part 1 is provided, a stable cover can be obtained. In FIG. 3, the double circle indicates the center of the plate portion, and the black circle indicates the center of gravity of a triangle formed by connecting the convex portions at three locations.

  In addition, for example, in the case where the shape of the convex portion is a quadrangular prism as shown in FIG. 2 with an emphasis on stability when installed and ease of manufacture, these convex portions provided at three places are arranged. As shown in FIG. 3 (b), it is preferable that the directions are all in the same direction as the hot gas flow. If it does in this way, the flow of a hot gas will not be blocked | interrupted by the convex part 1 more. Of course, the shape of the convex portions constituting the cover according to the present invention is not limited to the exemplified ones, but all the objects to be fired are sintered in a good state without thermal segregation. Therefore, it is necessary to make the gap 3 formed between the flat surface of the plate portion 2 and the surface on which the setter firing object is stacked have substantially the same spacing. For this reason, it is necessary to make the height of the three convex portions 1 provided in the vicinity of the outer periphery of the plate portion 2 substantially the same as the plate portion 2 having a flat surface. In this way, when a cover is put on the setter, a narrow gap having a uniform height is formed between the setter surface and the flat surface of the plate part constituting the cover. The cover is kept stable.

Furthermore, in the present invention, it is preferable that the convex portion is configured so that the area of the portion in contact with the setter is in a narrow range of 200 mm ² or less. By covering the setter in this way, when the cover is placed on the setter, it is possible to stably form a uniform height gap with the setter by sufficiently supporting the plate portion having a flat surface. In addition, it is possible to extremely reduce the part that obstructs the passage of the volatile gas and the hot gas. As a concrete thing of the shape of a convex part, although depending also on the magnitude | size of the to-be-baked object made into object, for example, height is about 1.5-3.0 mm, width is about 3-6 mm, and length is Examples include a rectangular column shape having a height of about 20 to 30 mm, and a rectangular column shape having a height of about 0.5 to 1.0 mm, a width of about 3 to 6 mm, and a length of about 8 to 16 mm. Of course, it may be cylindrical or polygonal.

Here, as an ultra-small to-be-fired object (part) for which the cover according to the present invention is used in the heat treatment process, a micro-shaped ultra-small ceramic functional material used for a homogeneous and high-quality product General. More specifically, various ceramic thin films (tapes or sheets), bulk (constant, etc.) used for various ceramic electronic devices such as multilayer capacitors, piezoelectric elements, ferrite elements, high frequency ceramics, etc. It can be used in the manufacture of various micro components such as those having a size. For example, volume of 3 mm ³ or less, more volume is very useful for 0.5 mm ³ The following very small parts. Specifically, length × width × height are 0.4 × 0.2 × 0.2 (mm), 0.6 × 0.3 × 0.3 (mm), and 1.0 × 0, respectively. .6 x 0.5 (mm), 2.0 x 1.25 x 1.25 or less (mm), and more It can be used effectively.

  Firing, etc. in the manufacturing process of the above-described microminiature parts is performed uniformly without causing uneven firing, and it is natural to prevent contamination of these parts at the stage of firing, etc. A high yield is required to obtain a product with excellent properties. Therefore, the volatilization gas from the object to be fired or setter stays in the part where the object to be fired is placed, or the flow of the hot gas forced into the furnace is hindered to perform uniform firing or the like. It is necessary to effectively prevent variations in the products caused by not being broken, and further disappearance of the ultra-small fired product from the setter due to the flow of hot gas or the like forced into the furnace.

  On the other hand, if the cover according to the present invention is used, as described above, uniform and efficient firing or the like can be performed on all the objects to be fired on the setter in the process of firing and the like. Can be effectively prevented from disappearing from the setter. As a result, it is possible to simultaneously maintain the quality of the microminiature parts obtained after firing and improve the product yield.

  The cover according to the present invention having the above shape can be easily formed by the following method, for example. First, at least a binder is added to and mixed with ceramic powder as described below, and shape retention is imparted to the ceramic powder to produce a block-shaped molded product having a plurality of through holes. Next, the molded product is dried and then fired to obtain a block-shaped ceramic sintered body, and then the fired body is cut into a thin plate to separately form a plate portion and a convex portion. Next, the desired shape of the convex portion is bonded to the desired three locations of the plate portion using an inorganic adhesive as will be described later, and then integrated by firing, and the convex portions are located at the three locations. The provided cover according to the present invention is obtained.

  As the ceramic powder used when manufacturing the cover made of the ceramic sintered body according to the present invention, the following can be used. For example, ceramic powder such as alumina, zirconia, silica, magnesia, mullite, cordierite, silicon nitride, silicon carbide, or a composite material containing these as a main component can be used. These may be used alone or as a mixture of two or more materials with an appropriate composition. In the present invention, it is particularly preferable to use a material that does not adversely affect the part to be fired by the volatilization gas or the like when firing the part to be fired.

  In addition, for example, when forming an alumina cover, a material containing 70% by mass or more of alumina may be used. However, a forming material is appropriately selected and used according to the situation in which the cover is used. It is preferable to do. For example, in an application to be used at a high temperature, it is preferable to use a forming material in which the alumina content is 78 to 85% by mass and silica is contained and mixed, and the constituent phase after firing is mullite-alumina. . Specific materials include, for example, a powder with an alumina content of 99% by mass made by Showa Denko, an alumina content of 80% by mass and a silica content of 20% by mass provided by Mino Ceramics Corporation. And a mixed powder in which the constituent phase after firing is mullite-alumina.

Further, when zirconia is used, there is an advantage that a material having excellent strength can be obtained even if the thickness is reduced as compared with other materials. When pure zirconia is used, cracks may occur due to the above volume expansion that occurs during firing. Therefore, in order to achieve excellent durability, as zirconia, CaO, MgO, Y ₂ O _3, etc. It is preferable to use partially stabilized zirconia or stabilized zirconia to which an additive has been added. Since zirconia is more expensive than alumina and silica, it is preferable to use a mixed powder of alumina and silica from the viewpoint of economy. Examples of the particle size of the ceramic powder used include those having an average particle size of 0.3 to 3 μm.

  As a binder for imparting shape retention to the ceramic powder as described above, a molded product having a desired shape can be obtained from the ceramic powder by imparting appropriate shape retention to the powder material as mentioned above. Any material can be used as long as it can be formed and can maintain its shape without causing cracks when the molded product is dried thereafter. Furthermore, it is preferable to use what can easily remove the binder from the molded product in the firing step of firing the molded product. The addition ratio of the binder is preferably about 2 to 10% by mass with respect to the ceramic powder material.

  As a specific binder, an organic compound which has a characteristic that it melts during heating and exhibits an appropriate viscosity and does not remain after being heated and fired to obtain a fired body may be used. 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. In particular, it is preferable to use a water-soluble cellulose ether which is a derivative of cellulose. Among them, it is preferable to use methylcellulose. Methyl cellulose has been conventionally used as a binder during extrusion molding of fine ceramic products, and can be suitably used in the present invention.

  As an inorganic adhesive for integrating a plate portion having a flat surface made of a ceramic sintered body and three convex portions made of a ceramic sintered body, for example, ceramic powder such as alumina and methyl cellulose A material prepared by adding water to a raw material composed of a binder and a resin dispersant can be used.

  The following method is mentioned as a specific method of manufacturing the plate part and the convex part constituting the cover according to the present invention. First, a block-shaped molded product is prepared using a ceramic material made of the raw material as described above and provided with shape retention, and this is fired to obtain a block-shaped fired body. Next, the fired body is preferably cut to a desired thickness of 2.0 mm or less to form a plate portion having a flat surface. The shape of the block-shaped molded product may be any as long as it can cover the setter when it is cut thinly to form a plate portion. For example, the cross-sectional area may be a polygon such as a circle, an ellipse, a triangle, a square, or a pentagon. The method for producing the block-shaped molded product is not limited, but in order to have a plurality of through holes, it is preferable to form the block-shaped molded product by extrusion molding. In addition, a convex part can be suitably obtained from the end material which formed the board part.

  As a specific method for forming a block-shaped molded product by extrusion molding, first, a binder is added to a raw material ceramic powder, and the resulting kneaded product is mixed and kneaded with an extrusion molding machine. If it extrudes via, a rod-shaped molding can be obtained easily. At this time, extrusion molding is performed using a die that can obtain a molded product in which a plurality of linear through-holes having openings of a desired shape are provided. Moreover, when obtaining a sintered compact from the block-shaped molded object obtained above, for example, a molded object is first dried at the temperature of about 30-80 degreeC, and the molded object after drying is 1400-1700 degreeC. It is preferable to fire.

  As a method of cutting the fired body obtained as described above to obtain a member for a plate part or a convex part, the fired body is cut with a cutting machine as described below and processed into a plate-like plate part. To do. 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 in producing a thin cover. A thin plate-like plate portion having a plurality of through-holes by horizontally cutting the position of the broken line shown in the drawing of the block-like fired product shown in FIG. 4 using an inner circumferential slicer or the like ( 2B) can be easily manufactured.

  Next, in the thin plate-like plate portion obtained as described above, in the desired three locations near the outer periphery of the surface facing the setter when used, for the convex portion obtained as described above. The member is attached using the inorganic adhesive described above. After that, by baking at a temperature of about 1500 ° C., the plate portion and the convex portion are bonded and integrated, and the cover according to the present invention in which the convex portions are provided at three locations near the outer periphery on one side of the plate portion. obtain.

Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples.
<Examples 1 and 2>
In this example, a powder having an average particle size of 1.5 μm and an alumina content of 80% by mass and a silica content of 20% by mass was used as the forming material so that the constituent phase after firing was mullite-alumina. In order to impart shape retention to the powder, methylcellulose was contained at a ratio of 5% by mass with respect to the powder. Then, these materials are mixed and kneaded by an extrusion molding machine (manufactured by Takahama Kogyo Co., Ltd.) to obtain a kneaded product having shape retention. Subsequently, the above kneaded product is obtained by the above extrusion molding machine. Two types of cylindrical shaped products having different sizes were formed. The cylindrical shaped product has a thickness of about 100 mm and has a plurality of minute holes penetrating in the height direction of the cylinder. The shape of the through hole was a square whose cross section was 0.6 or 0.8 mm on one side.

  Next, after drying each molded product obtained above at 100 ° C. for 10 hours, the temperature was raised to 1,550 ° C. at 60 ° C./hour, and firing was performed at that temperature for 120 minutes to obtain a mullite-alumina fired product. Got. Next, the periphery of the obtained cylindrical mullite-alumina fired product having a plurality of through-holes was cut vertically using an inner circumference slicer manufactured by Tokyo Seimitsu Co., Ltd. as a cutting device to form a prismatic shape. . Next, using the same cutting apparatus, it cut | disconnected horizontally so that thickness might become substantially constant, and produced the board part from which size shown in Table 1 differs, respectively. Moreover, the convex part from which the shape shown in Table 1 differs in the end material at the time of producing a board part was produced.

Next, for each plate part obtained as described above, the convex portions of each size shown in Table 1 are combined, and an inorganic slurry having the following composition is used at three locations shown in FIG. And glued. Next, this was heated up to 1500 ° C. and heat-treated to obtain a cover of this example in which each plate portion was integrally provided with three convex portions. Table 1 shows the cover sizes obtained.
・ Alumina 60%
・ Methylcellulose (binder) 8%
・ Resin dispersant 1%
・ Water 31%

[Evaluation]
Using the setter S made of alumina of 99% by mass having the shape shown in FIG. 1 and the cover according to each example having the shape shown in Table 1, firing was performed when manufacturing a microminiature component. . For comparison, similar firing was performed without using a cover. At this time, 100,000 to be fired on each setter to obtain an ultra-small multilayer ceramic capacitor having a size after firing of 0.4 × 0.2 × 0.2 mm is used for normal firing. Went.

  The setter used above has the shape shown in FIG. 1, but the portion of the stacking surface on which the object to be fired is placed is a square of 152 × 152 mm in Example 1 and 130 × 130 mm in Example 2. The thickness is 4 mm, and the outer peripheral portion on the stacking surface side has an outer edge with a rise of 1 mm from the surface on which the object to be fired is placed and a width of about 5 mm. Due to this outer edge, the ultra-small fired article placed on the setter does not easily roll off from the setter surface. In addition, the four corners of the outer edge are provided with platforms for stacking 25 × 5 × 4 mm setters, so that a plurality of setters having the same shape can be stacked as shown in FIG. It has become. Furthermore, the setter shown in FIG. 1 is provided with shallow recesses at the four corners on the opposite side to the setter loading surface so that the setter is stable when the setters are stacked. The recess is configured such that the uppermost part of the table for stacking the setter is fitted into the shallow recess. By doing in this way, as shown in FIG.1 (c), several setters are piled up in the stable state.

  In the evaluation, the plate-like setters in the above-described state were stacked in three stages, placed on the stacking surface of each setter with the cover of each example covered by each object to be fired, and normal firing was performed in this state. . Moreover, in the comparative example, it tested about the case where it baked only with a setter, without using a cover. As a result, as shown in Table 1, it can be confirmed that when the cover according to the example is used, the product yield is significantly improved in any case as compared with the comparative example in which the cover is not used. It was. In addition, the multilayer ceramic capacitors obtained after firing were all fired in a good state, and it was confirmed that they were of excellent quality.

  As an application example of the present invention, there is a ceramic cover that can perform firing and the like when manufacturing a microminiature component such as a multilayer ceramic capacitor in a good state and with a high yield. Furthermore, the use of such a cover can improve the quality and productivity of ultra-small parts, thereby improving the quality of ceramic electronic device products using these micro-parts and improving the economic efficiency. Can contribute.

It is a figure for demonstrating the use condition and effect | action of the ceramic-made covers of this invention. It is a schematic diagram which shows an example of the ceramic-made covers of this invention. It is a figure which shows typically the position of the three convex parts attached to a board part. It is a figure for demonstrating the manufacturing method of the ceramic-made covers of this invention.

Explanation of symbols

1: Convex part 2: Plate part 3: Gap 4: Line to be cut 5: Through hole S: Setter B: Baking object

Claims (6)

  A ceramic cover used in a heat treatment process or firing process performed when manufacturing microminiature parts and covered with an object to be fired on a setter, and a flat surface provided with a plurality of through holes And a convex portion made of a ceramic sintered body provided in the vicinity of the outer periphery of one surface of the plate portion and disposed on the setter, the convex portion The gap is formed so that a gap having substantially the same interval is formed between the flat surface of the plate portion and the surface of the setter to be fired. Made of cover.   2. The ceramic cover according to claim 1, wherein the through hole is provided over the entire surface of the plate portion, and the longest portion of the opening is 3.0 mm or less.   The ceramic cover according to claim 1 or 2, wherein the distance is 3.0 mm or less.   The convex portions are provided at three locations in the vicinity of the outer periphery of one surface of the plate portion, and the positional relationship between these convex portions is a triangular center of gravity formed by connecting the convex portions. The ceramic cover according to any one of claims 1 to 3, wherein the cover is configured to be near the center.   The ceramic cover according to any one of claims 1 to 4, wherein a shape of the plate portion is a square having a thickness of 2.0 mm or less. Each area of the part which contacts the setter of the said convex part is 200 mm < ² > or less, The ceramic-made covers of any one of Claims 1-5.

Images