JP4073221B2 - Ceramic firing tool material and manufacturing method thereof - Google Patents

Description

【００３４】
【表２】

以上の実施例では第１の骨材として電融アルミナを用いているが、本発明においては、第１の骨材として電融アルミナに代えて又はそれと併用して焼結アルミナを用いることができる。それらの場合も、第１の骨材として電融アルミナを用いた場合と同等な作用効果が得られることが確認された。
【００３５】
【発明の効果】
以上説明したように、本発明によれば、電融アルミナ及び／又は焼結アルミナからなる粒径１０〜３００μｍの第１の骨材と、電融ムライトからなる粒径１０〜３００μｍの第２の骨材と、ローソーダ仮焼アルミナからなる粒径１０μｍ未満の結合材との組み合わせを用い、しかも全体におけるＡｌ₂ Ｏ₃ ／ＳｉＯ₂ 比を８５／１５〜９５／５の範囲内としたので、被焼成物焼成時の高温においてもムライトの分解によるシリカの揮発が十分に抑制され、かくして被焼成物に対する斑点状変質の発生を抑制することが可能な焼成用道具材が提供される。[0001]
BACKGROUND OF THE INVENTION
The present invention belongs to the technical field of ceramic production, and in particular, ceramic firing used for mounting the forming body in firing when an alumina ceramic fired body is obtained from a forming body made of alumina. The present invention relates to a tool material and a manufacturing method thereof.
[0002]
The ceramic firing tool material of the present invention is suitably used, for example, to obtain a colored alumina ceramic fired body such as a package substrate for a semiconductor device by firing a green body.
[0003]
[Prior art and problems to be solved by the invention]
Conventionally, a substrate made of a colored alumina ceramic (for example, brown alumina) has been used as a package substrate for a semiconductor device.
[0004]
When firing the colored alumina ceramic, in order to minimize the deformation of the formed body due to firing, the formed body is placed on a ceramic mounting table called a firing tool material.
[0005]
The firing tool material is composed of an aggregate and a binder. The binder is a mixture of alumina fine powder and clay fine powder, and mullite is formed by the reaction at the time of firing, thereby generating a binding force between the aggregates and obtaining mechanical strength as a tool material for firing. . As a characteristic of the material itself, mullite has the feature that strength does not decrease even at high temperatures, and therefore has the effect of suppressing deflection deformation at high temperatures of baking tool materials, and ceramics such as package base materials for semiconductor devices. It is used as a binder for tool materials for firing electronic components.
[0006]
However, the mullite binder is easily decomposed into alumina (Al ₂ O ₃ ) and silica (SiO ₂ ), which are oxides constituting the mullite binder, at high temperatures, particularly in a reducing atmosphere. When the material to be fired is a colored alumina ceramic molded body that gradually accumulates on the surface of the firing tool material as the number of times the tool material is used increases, There is a problem that the surface of the object to be fired that comes into contact with the material is likely to be deteriorated early (that is, while the number of times of use of the firing tool material is small). Alteration usually occurs in spots. When such a change occurs, the characteristic (for example, insulation) of the electronic component which is the molded body changes from the required one, and in a severe case, the electronic component becomes a defective product due to the deterioration of the characteristic.
[0007]
In order to avoid the occurrence of such a problem, it is conceivable to use only alumina that does not easily deteriorate during firing of the material to be fired in both the aggregate and the binder in the firing tool material. Warpage as a result of high-temperature creep deformation during firing is likely to occur, and the life as a tool material for electronic component firing that requires flatness during firing of the object to be fired becomes short.
[0008]
Accordingly, the object of the present invention is to provide a firing tool material that has little deformation during firing of the object to be fired and that hardly changes the quality of the alumina ceramic formed body during firing of the object to be fired. is there.
[0009]
[Means for Solving the Problems]
According to the present invention, the object as described above is achieved.
Manufactured through firing at a temperature in the range of 1700 to 1830 ° C. in an air atmosphere,
A first aggregate having a particle size of 10 to 300 μm made of electrofused alumina and / or sintered alumina, a second aggregate having a particle size of 10 to 300 μm made of electrofused mullite, and a binder. The binder is composed of only low-soda calcined alumina and has a particle size of less than 10 μm ,
The overall Al ₂ O ₃ / SiO ₂ ratio [by weight] is in the range of 85/15 to 95/5 ,
A ceramic firing tool characterized in that the aggregate / binder ratio [by weight] is in the range of 80/20 to 60/40 ;
Is provided. Here, the aggregate weight is the sum of the weight of the first aggregate and the weight of the second aggregate.
[0011]
In addition, according to the present invention, the object as described above is achieved.
A method for producing the above-mentioned ceramic firing tool material, comprising: a first aggregate-forming powder composed of fused alumina and / or sintered alumina; and a second aggregate-formed powder composed of electrofused mullite. The mixture obtained by mixing the body, the powder for forming the binder consisting only of the calcined alumina, the organic powder binder, and the liquid binder is kneaded, dried, and 1700 to 1830 in an air atmosphere. A method for producing a ceramic firing tool material, characterized by firing at a temperature within a range of ° C.
Is provided.
[0013]
The fused alumina used as the first aggregate is described as refractory term 255 in JIS-R2001, and is a high alumina material melted in an electric furnace. The sintered alumina used as the first aggregate is described as refractory term 254 in JIS-R2001, and is a high alumina material sintered in a kiln. Mullite is a JIS-R2001 have been described as refractory term 249, 3Al ₂ O ₃ / basic formula silicate alumina having a 2SiO _2. The electrofused mullite used as the second aggregate is obtained by melting a raw material having a mullite composition in an electric furnace.
[0014]
Calcination is described as refractory term 102 in JIS-R2001, and is a heat treatment that is preliminarily performed to change the raw material physically or chemically, and calcined alumina uses Al (OH) ₃ as a kiln. It is roasted in a furnace to Al ₂ O ₃ . The soda calcined alumina used as the binder is calcined alumina having a Na ₂ O content of 0.1% by weight or less. In the present specification, the one in which the Na ₂ O content exceeds 0.1 wt% is referred to as high soda calcined alumina.
[0015]
In the ceramic firing tool material of the present invention, the first and second aggregates have a particle size of 10 to 300 μm and the binder has a particle size of less than 10 μm. Therefore, the ceramic firing tool material has uniform and sufficient strength and stability. Have. When the particle sizes of the first and second aggregates are too small, the creep characteristics are inferior and deformation during firing tends to increase. On the other hand, if the particle sizes of the first and second aggregates are too large, a smooth surface cannot be obtained, and there is a tendency that scratches and pinholes are likely to be generated in the object to be fired.
[0016]
In addition, since a binder made of calcined alumina having a particle size of less than 10 μm is used, a low-melting material is not formed, and thus the material to be fired is altered due to a reaction with the material to be fired. This is unlikely to occur.
[0017]
A binder made of low-soda calcined alumina is preferably one having a particle size of less than 10 μm and having a wide particle size distribution because it can exhibit high filling properties and thus high bonding strength due to high density and low firing shrinkage. Here, the wide range of particle size distribution is 10 to 30% by weight in the range of particle size less than 2 μm; 30 to 50% by weight in the range of particle size of 2 μm or more and less than 4 μm; particle size of 4 μm or more and less than 6 μm 10 to 30% by weight in the range of 10 to 30% by weight; 10 to 30% by weight in the range of 6 μm to less than 8 μm; 5 to 25% by weight in the range of 8 μm to less than 10 μm Say. Moreover, high-filling alumina means what shows a high density (bulk density) of 2.30 or more.
[0018]
In the present invention, the aggregate / binding material ratio, which is the ratio of the total weight of the first and second aggregates to the weight of the binding material, is preferably in the range of 80/20 to 60/40. . When the ratio of the weight of the binder to the total weight of the aggregate and the binder exceeds 40%, the firing shrinkage increases, so that warpage and deformation tend to increase, and stable production tends to be impossible. On the other hand, when the ratio of the weight of the binder to the total weight of the aggregate and the binder is less than 20%, a sufficient bonding force cannot be obtained, the required strength cannot be obtained, and the surface of the baking tool material becomes rough. It tends to be easy to shed.
[0019]
In the present invention, the Al ₂ O ₃ / SiO ₂ ratio, which is the ratio of Al ₂ O ₃ weight to SiO ₂ weight in the entire firing tool material, is in the range of 85/15 to 95/5. Occurrence of spot-like alteration in the fired product during firing of the fired product is prevented, the creep resistance is good even at a high temperature during firing of the fired product, and deformation of the fired product is prevented. When SiO ₂ is excessive in the Al ₂ O ₃ / SiO ₂ ratio, spot-like alteration in the fired product tends to occur when the fired product is fired. Further, when Al ₂ O ₃ is excessive in the Al ₂ O ₃ / SiO ₂ ratio, the creep resistance is lowered at a high temperature during firing of the fired product, and warpage deformation is likely to occur. Will also be easily deformed.
[0020]
The shape of the tool material is, for example, a flat plate shape, but is not limited thereto. In the case of a flat plate shape, the tool material has a thickness of 5 to 12 mm and a length and width of 100 to 300 × 100 to 300 mm, for example.
[0021]
Examples of the organic powder binder used in the method for producing a ceramic firing tool material of the present invention include polyvinyl alcohol, dextrin, and methylcellulose. Examples of the liquid binder used in the method for producing a ceramic firing tool material of the present invention include an aqueous ammonium polycarboxylate solution, a wax emulsion, and diethylene glycol. A mixer is used for kneading the mixture, and a vibration molding machine or a hydraulic press is used for molding.
[0022]
In the present invention, since mullite is not used as the binder, there is no problem of silica generation due to mullite decomposition even at a high temperature during firing the firing object, and the occurrence of spotted alteration in the firing object is prevented. Further, in the present invention, since electromelting mullite is used as a part of the aggregate, the creep resistance is good even at a high temperature during firing the object to be fired, and therefore, deformation of the object to be fired is prevented. . Moreover, since this electromelting mullite is coarse, there is little decomposition | disassembly of a mullite and there is also little alteration of a to-be-baked material.
[0023]
In the method for producing a ceramic firing tool material of the present invention, firing is performed at a temperature in the range of 1700 to 1830 ° C. in an air atmosphere. When the firing temperature is less than 1700 ° C., firing is insufficient, sufficient strength of the tool material cannot be obtained, deflection resistance is inferior, and degranulation is likely to occur from the surface, which tends to adversely affect the object to be fired. On the other hand, when the firing temperature exceeds 1830 ° C., the shrinkage during firing tends to be large, and the resulting tool material tends to be greatly deformed. As described above, when the firing temperature of the tool material is less than 1700 ° C. or exceeds 1830 ° C., a stable tool material cannot be obtained.
[0024]
【Example】
Hereinafter, the present invention will be described by way of examples.
[0025]
Examples 1-8 :
A first aggregate-forming powder made of electrofused alumina with a particle size of 10-300 μm, a second aggregate-forming powder made of electrofused mullite with a particle size of 10-300 μm, and a wide range with a particle size of less than 10 μm Particle size distribution [18% by weight in the range of particle size less than 2 μm; 34% by weight in the range of particle size of 2 μm or more and less than 4 μm; 21% by weight in the range of particle size of 4 μm or more and less than 6 μm; Binder forming powder comprising low-soda calcined alumina with a density of 2.4 having a diameter of 6 μm or more and less than 8 μm in a range of 17% by weight; a particle size in a range of 8 μm or more and less than 10 μm in a range of 10% by weight. Were mixed with an organic powder binder made of polyvinyl alcohol and a liquid binder made of an aqueous solution of ammonium polycarboxylate to obtain a mixture. This mixture contained no clay.
[0026]
This mixture is kneaded with a mixer, formed into a plate shape having a size of 100 × 100 × 5 mm with a vibration molding machine, dried, and fired at a temperature shown in Table 1 below in an air atmosphere. Got. At the same time, in order to obtain a test piece for measuring deflection deformation, a sample having a size of 20 × 100 × 5 mm was cut out from the firing tool material.
[0027]
The composition of the obtained firing tool material (the weight of the first aggregate, the second aggregate and the binder, the Al ₂ O ₃ / SiO ₂ ratio, and the aggregate / binder ratio) is shown in Table 1 below. These baking tools did not contain clay.
[0028]
Using the obtained firing tool material, a green body made of brown alumina ceramic was placed thereon, fired at 1400 ° C. in the air, and cooled to room temperature. The obtained fired body was removed, and subsequently, using the same firing tool material, a new molding body was placed in the same manner. Thereafter, firing was repeated in the same manner.
[0029]
The number of times of firing was examined for the first occurrence of spot-like alteration on the contact surface of the fired body with the tool material for firing. The results are shown in Table 1 below. In addition, once spot-like alteration appears on the contact surface of the fired body with the tool material, it has been confirmed that spot-like alteration appears in subsequent firing, and therefore, alteration appears first. The number of firings can be used as a guide for tool life.
[0030]
Using the test piece for deflection deformation, supported from the lower surface side with a span of 90 mm, a 200 g weight is placed on the center of the upper surface, held at 1400 ° C. for 10 hours in an electric furnace, and subjected to creep deformation ( The difference between the height of the periphery of the upper surface and the height of the center of the upper surface was measured. The results are shown in Table 1 below.
[0031]
Table 1 shows the overall evaluation. The criteria for the overall evaluation were as follows:
A: The number of firings until the occurrence of alteration exceeds 100 times, and the deflection deformation of the firing tool material is less than 1.5 mm;
○: The number of firings until the occurrence of alteration is 50 times or more, and the deflection of the firing tool material is less than 3 mm (except for ◎);
X: The number of firings until the occurrence of alteration is 49 times or less, or the deflection deformation of the firing tool material is 3 mm or more.
[0032]
Comparative Examples 1-8 :
It implemented like Example 1-8 except having used what was shown in the following Table 2 by the weight described in Table 2 as a 1st aggregate, a 2nd aggregate, and a binder. The density of the high soda calcined alumina was 2.0. The obtained results are shown in Table 2 in the same manner as in Examples 1-8.
[0033]
[Table 1]

[0034]
[Table 2]

In the above embodiment, fused alumina is used as the first aggregate, but in the present invention, sintered alumina can be used as the first aggregate instead of or in combination with fused alumina. . In those cases, it was confirmed that the same effect as that obtained when electrofused alumina was used as the first aggregate was obtained.
[0035]
【The invention's effect】
As described above, according to the present invention, the first aggregate having a particle size of 10 to 300 μm made of fused alumina and / or sintered alumina and the second aggregate having a particle size of 10 to 300 μm made of fused mullite. Since a combination of an aggregate and a binder made of low soda calcined alumina and having a particle size of less than 10 μm was used, and the Al ₂ O ₃ / SiO ₂ ratio in the whole was in the range of 85/15 to 95/5, A firing tool material is provided in which the volatilization of silica due to the decomposition of mullite is sufficiently suppressed even at a high temperature during firing of the fired product, and thus the occurrence of spotted alteration to the fired product can be suppressed.

Claims (2)

Manufactured through firing at a temperature in the range of 1700 to 1830 ° C. in an air atmosphere,
A first aggregate having a particle size of 10 to 300 μm made of electrofused alumina and / or sintered alumina, a second aggregate having a particle size of 10 to 300 μm made of electrofused mullite, and a binder. The binder is composed of only low-soda calcined alumina and has a particle size of less than 10 μm,
The overall Al ₂ O ₃ / SiO ₂ ratio [by weight] is in the range of 85/15 to 95/5,
A ceramic firing tool comprising an aggregate / binder ratio [by weight] in the range of 80/20 to 60/40. A method for producing a ceramic firing tool material according to claim 1 , wherein the first aggregate forming powder is composed of fused alumina and / or sintered alumina, and the second aggregate is composed of fused mullite. A mixture obtained by mixing a powder for use with a binder, a powder for forming a binder consisting only of calcined alumina, an organic powder binder, and a liquid binder is kneaded, dried, and dried in air at 1700. A method for producing a ceramic firing tool material, comprising firing at a temperature in the range of -1830 ° C.