KR20190085482A - Setter for firing - Google Patents

Abstract

An objective of the present invention is to provide a setter for firing in which delamination of a coating layer is suppressed. The setter for firing has the coating layer on a substrate. The coating layer is exposed on a surface of the setter for firing. In the setter for firing, a thickness T1 of a minimum thickness part and a maximum thickness part T2 of the coating layer in any cross section within a 400 μm × 400 μm surface satisfy the following formula (1), T1/T2<=0.4.

Description

{SETTER FOR FIRING}

This specification discloses a technique relating to a firing setter.

When the object to be fired is fired, a firing jig such as a setter is used to place the object to be fired. In the firing setter (firing container) of Patent Document 1, a coating layer of aluminum and zirconia is formed on the surface of the substrate in order to suppress the reaction between the substrate and the fired product. In Patent Document 1, the coating material having a large particle size is applied to a base material to increase the porosity of the coating layer, thereby suppressing peeling of the base material and the coating layer due to the difference in thermal expansion between the base material and the coating layer. Further, in Patent Document 1, since the surface roughness Ra of the coating layer is increased by using a coating material having a large particle diameter, the surface of the coating layer is polished after the coating layer is formed.

Patent Document 1: Japanese Patent Application Laid-Open No. 2007-45641

In Patent Document 1, the surface of the coating layer is polished to smooth the surface of the coating layer. In other words, Patent Document 1 makes the thickness of the coating layer uniform. Patent Document 1 not only limits the particle diameters of usable coating materials, but also requires a polishing process after forming a coating layer. There is a need for a firing setter in which the limit of the raw material (coating material) to be used is small and can be easily manufactured and the peeling of the coating layer is suppressed. It is an object of the present invention to provide a new firing setter in which peeling of a coating layer is suppressed based on a technical idea which is not conventionally known.

The inventors of the present invention have studied the cause of the peeling of the coating layer and found that the surface of the coating layer is smooth (the thickness of the coating layer is uniform), thereby facilitating the peeling of the coating layer. That is, it has been found that a technique conventionally performed for suppressing peeling of the coating layer promotes peeling of the coating layer as a result. The inventors of the present invention succeeded in suppressing the peeling of the coating layer by adopting the opposite method to that of the conventional technical sense. The firing setter disclosed in this specification is based on the above knowledge.

The firing setter disclosed in this specification has a coating layer on a substrate. In this firing setter, the coating layer is exposed on the surface of the firing setter, and the thickness T1 of the minimum thickness portion and the thickness T2 of the maximum thickness portion of the coating layer at an arbitrary cross section in the plane of 400 mu m x 400 mu m satisfy the following formula (1). Incidentally, the phrase &quot; having a coating layer on a substrate &quot; includes both a form in which the substrate and the coating layer are in direct contact with each other and a form in which another layer is formed between the substrate and the coating layer.

T1 / T2? 0.4 (1)

The firing setter is simply that the surface of the coating layer is not smooth in a very small range (arbitrary section within a plane of 400 mu m x 400 mu m). That is, in the above-mentioned firing setter, the coating layer is uniformly formed in the thickness direction within a minute range (height difference). Specifically, the thickness T1 of the minimum thickness portion of the coating layer is 40% or less of the thickness T2 of the maximum thickness portion (the height difference ratio is 40% or less) at an arbitrary section in the 400 mu m x 400 mu m plane. In other words, the thickness T2 is at least 2.5 times the thickness T1. In the firing setter, since the coating layer has a high level difference, the stress (the stress that causes the coating layer to stretch the substrate) can be relaxed in the plane direction (direction orthogonal to the thickness direction) when the coating layer is thermally expanded. The tensile stress generated between the base material and the coating layer is relaxed, so that peeling of the coating layer from the base material can be suppressed. In addition, the firing setter forms a high level difference in the coating layer within a small range, and it is not necessary to form irregularities on the surface of the firing setter as a whole.

In the firing setter, it is preferable that the thickness T1 of the coating layer (thickness of the minimum thickness portion) and the thickness T2 (thickness of the maximum thickness portion) satisfy the following formula (2).

0.05? T1 / T2 (2)

By satisfying the above formula (2), it is prevented that the minimum thickness portion (thickness T1) of the coating layer becomes too thin (less than 5% of the maximum thickness portion). The coating layer repeatedly thermally expands, thereby preventing exposure of the substrate (or the intermediate layer interposed between the coating layer and the substrate). As a result, it is possible to prevent the object to be contacted with the other layer (substrate or intermediate layer) other than the coating layer, and to prevent the object to be reacted with the other layer.

As an index indicating that the coating layer has a difference in height, the following indexes are also exemplified. It is preferable that the firing setter disclosed in this specification satisfies the following index together with the above-mentioned formula (1) or the above-mentioned formulas (1) and (2). That is, the first plane including the back surface of the coating layer of the minimum thickness portion orthogonal to the thickness direction of the coating layer, and the second plane including the surface of the coating layer of the maximum thickness portion orthogonal to the thickness direction of the coating layer , The coating layer occupies 70% or less (the area ratio of the coating layer is 70% or less).

When the coating layer is completely flat (no difference in height), the proportion of the coating layer in the rectangular area is 100%. By satisfying the index together with the formula (1) or the formulas (1) and (2), it is easy to form a difference in height in the coating layer, and the firing setter in which peeling of the coating layer is suppressed can be quantitatively obtained.

In the above firing setter, it is preferable that an intermediate layer having a coefficient of thermal expansion greater than that of the substrate and a coefficient of thermal expansion smaller than that of the coating layer is formed between the substrate and the coating layer. By forming such an intermediate layer, the intermediate layer functions as a stress relaxation layer, and peeling of the coating layer can be further suppressed.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 shows a view for explaining a method for measuring the ratio of the height difference of the coating layer.
Fig. 2 shows a view for explaining a method of measuring the area ratio of the coating layer.
3 is a schematic view of a firing setter having an intermediate layer.
Fig. 4 shows a schematic diagram for explaining the acquisition position of the evaluation sample.
Fig. 5 shows the characteristics of the firing setter of the example and the result of the repeated heating test.
Fig. 6 shows a SEM image of the firing setter of the example. Fig.

(Firing setter)

The firing setter disclosed in this specification is used for disposing a fired product when fired products such as electronic parts and ceramic members are fired. The surface (placement surface) shape of the firing setter may be a polygonal shape such as a triangle or a quadrangle, or may have a curved outer shape such as a circle or an ellipse. Further, the firing setter may be provided with a rib at an end portion (outside of the arrangement portion in which the object to be disposed is arranged). The firing setter includes a base material and a coating layer covering the base material.

(materials)

The base material preferably contains silicon carbide (SiC) and silicon (Si) as main components. That is, the sum of the mass of SiC and Si preferably accounts for 50 mass% or more of the mass of the substrate. SiC and Si are preferably contained in an amount of 60 mass% or more, preferably 70 mass% or more, more preferably 80 mass% or more, more preferably 90 mass% or more, Or more. It is preferable that the substrate contains a trace element other than SiC and Si. Examples of the trace element include iron (Fe), calcium (Ca), sodium (Na), magnesium (Mg), potassium (K) and aluminum (Al). Each of the trace elements is preferably contained in the base material in an amount of 0.01 to 3 mass%, and the total amount of the trace elements in the base material is preferably 0.01 to 3 mass%. In addition, the substrate can be molded by mixing and molding a C powder, a SiC powder, and an organic binder in the presence of metallic Si, in an inert gas atmosphere under reduced pressure or in a vacuum, and impregnating the metallic body with Si.

(Coating layer)

The coating layer is formed on the substrate and is exposed on the surface of the firing setter. It is preferable that the coating layer constitutes a contact surface in contact with the object to be treated. The coating layer may cover the entire surface of the firing setter, or may cover only the surface of the firing setter (the surface on which the object to be disposed is placed). The coating layer may be formed by applying a coating material to the surface of the base material, and then firing the base material at a temperature of 1100 to 1400 deg. The baking temperature after applying the coating material is preferably 1200 ° C or higher, preferably 1250 ° C or higher, and more preferably 1300 ° C or higher.

The coating layer is preferably a zirconium (Zr) compound as a main component. That is, it is preferable that the Zr compound occupies 50% by mass or more of the mass of the coating layer. The Zr compound may be contained in the coating layer in an amount of 60 mass% or more, preferably 70 mass% or more, more preferably 80 mass% or more, more preferably 90 mass% or more, Or more. Examples of the Zr compound include stabilized zirconia stabilized by calcium oxide (CaO) or yttria (Y ₂ O ₃ ), eutectic products of alumina and zirconia, and BaZrO ₃ and CaZrO ₃ . It is preferable that the coating layer contains a trace element other than the Zr compound. That is, the coating layer may contain 3 mass% or less of an element other than the Zr compound. As a trace element, Fe, Si, Ca, Na, Mg, K, Al and the like can be mentioned, and it is preferable that at least one of these elements is contained in the coating layer.

It is preferable that the coating layer has a high level difference (thickness unevenness) within a specific small range. Specifically, the thickness T1 of the minimum thickness portion and the thickness T2 of the maximum thickness portion of the coating layer in an arbitrary section within a 400 占 퐉 400 占 퐉 plane as viewed from the plane of the firing setter satisfies the following formula (1) It is good.

T1 / T2? 0.4 (1)

The thickness T2 (thickness of the maximum thickness portion) is preferably 10 to 100 mu m. The thickness T2 is preferably 20 占 퐉 or more, preferably 30 占 퐉 or more, 40 占 퐉 or more, and 50 占 퐉 or more. The thickness T2 is preferably 90 占 퐉 or less, more preferably 80 占 퐉 or less and 70 占 퐉 or less.

The thickness T1 (thickness of the minimum thickness portion) is preferably 0 to 40 mu m. The thickness T1 is preferably 1 占 퐉 or more. The thickness T1 is preferably 3 占 퐉 or more, more preferably 5 占 퐉 or more, more preferably 10 占 퐉 or more, and more preferably 20 占 퐉 or more. The thickness T1 is preferably 30 占 퐉 or less, and preferably 25 占 퐉 or less. When the thickness T1 is not 0 占 퐉, it is preferable that the thickness T1 and the thickness T2 satisfy the above formula (1) and satisfy the following formula (2).

0.05? T1 / T2 (2)

It can also be expressed as a ratio (area ratio) of the coating layer occupying a specific range as an index indicating that the coating layer has a height difference in the thickness direction. That is, the first plane including the back surface of the coating layer of the minimum thickness portion orthogonal to the thickness direction of the coating layer, and the second plane including the surface of the coating layer of the maximum thickness portion orthogonal to the thickness direction of the coating layer It is preferable that the ratio of the coating layer occupied by the coating layer is 70% or less. The area ratio of the coating layer is preferably not more than 65%, more preferably not more than 60%, more preferably not more than 55%, more preferably not more than 50%, more preferably not more than 45%, more preferably not more than 35% The area ratio of the coating layer is preferably 10% or more, more preferably 15% or more, and more preferably 20% or more. The smaller the ratio of the area occupied in the specific range (rectangular range), the more the area in which the coating layer is not present in the rectangular range, and the higher the height difference is likely to occur in the thickness direction of the coating layer.

(Middle layer)

It is preferable that an intermediate layer is formed between the coating layer and the substrate. The intermediate layer is preferably bonded to the coating layer and the substrate. That is, the intermediate layer preferably bonds the coating layer and the substrate. The main component of the intermediate layer is preferably an Al compound. The Al compound is preferably contained in an amount of 50 mass% or more, more preferably 60 mass% or more, more preferably 70 mass% or more, more preferably 80 mass% or more, more preferably 90 mass% Or more and preferably 95 mass% or more. As the Al compound, mullite (aluminum silicate) can be mentioned. In addition to the Al compound, the intermediate layer may contain one or more of Fe, Si, Ca, Na, Mg, and K as trace constituents.

The coefficient of thermal expansion of the intermediate layer is larger than that of the substrate and smaller than that of the coating layer. That is, the intermediate layer preferably functions as a stress relieving layer for relaxing the thermal stress (difference in thermal expansion) generated between the coating layer and the substrate. The thickness of the intermediate layer is preferably 50 to 200 mu m. The thickness of the intermediate layer is preferably 60 占 퐉 or more, preferably 70 占 퐉 or more, 80 占 퐉 or more, and 100 占 퐉 or more. The thickness of the intermediate layer is preferably 180 占 퐉 or less, and 160 占 퐉 or less. The thickness of the intermediate layer is preferably thicker than the thickness of the coating layer.

(Assessment Methods)

The method of measuring the coating layer and the position at which the sample to be measured are to be obtained will be described. Fig. 1 schematically shows a cross section of a sample 1 obtained by cutting a firing setter. The length (plane direction length) L1 of the sample 1 is 400 mu m. Sample 1 can be observed using an SEM (Scanning Electron Microscope) or the like. Sample 1 includes a base material 2 and a coating layer 4 formed on the base material 2. The coating layer 4 has a difference in height. It is possible to measure the thickness T1 of the minimum thickness portion 4a and the thickness T2 of the maximum thickness portion 4b of the coating layer 4 at an arbitrary cross section within the 400 占 퐉 400 占 퐉 plane of the firing setter have. Specifically, the thickness T1 is a distance from the surface of the coating layer 4 to the back surface of the coating layer 4 (the contact surface with the base material 2) in the minimum thickness portion 4a of the coating layer 4. Similarly, the thickness T2 is a distance from the surface of the coating layer 4 to the back surface of the coating layer 4 (the portion contacting the base material 2) at the maximum thickness portion 4b of the coating layer 4. [ By using the measured thickness T1 and thickness T2, it is possible to judge whether or not the above equations (1) and (2) are satisfied.

Fig. 2 shows a diagram in which the coating layer 4 of the sample 1 is surrounded by the rectangular region 6. Fig. The rectangular region 6 is perpendicular to the thickness direction of the coating layer 4 and is formed on the back surface of the coating layer 4 of the minimum thickness portion 4a with the coating layer 4 and the substrate 2 in the minimum thickness portion 4a, And a second plane 6b including a surface of the coating layer 4 of the maximum thickness portion 4b perpendicular to the thickness direction of the coating layer 4, . The ratio (area ratio) occupied by the coating layer 4 in the rectangular area 6 can be measured by creating the rectangular area 6 and using the image analysis software such as ImageNos.

When the intermediate layer 3 is formed between the coating layer 4 and the substrate 2 as in the sample 1a shown in Fig. 3, the thickness of the coating layer 4 from the surface of the coating layer 4 in the minimum thickness portion 4a (Distance between the substrate and the intermediate layer 3), the distance T1 can be obtained. The distance T2 can be obtained by measuring the distance from the surface of the coating layer 4 in the maximum thickness portion 4b to the back surface of the coating layer 4 (the contact portion of the base material and the intermediate layer 3). A plane perpendicular to the thickness direction of the coating layer 4 is formed on the back surface of the coating layer 4 in the minimum thickness portion 4a (the contact portion of the coating layer 4 and the intermediate layer 3 in the minimum thickness portion 4a) The first plane 6a can be obtained.

Fig. 4 shows a quadrangular (square) firing setter 10 as an example of a firing setter. The samples 1 and 1a were obtained in the standard position of the coating layer. That is, the measurement sample is obtained by avoiding a position where the state of the coating layer may become unusual. More specifically, the measurement region 14 is set at a position of a distance D12 from the side surface 12 of the firing setter 10, and the center of gravity 20 of the firing setter 10 The center of gravity 20 and the center of the circular portion 14a are set at the measurement position 22 as the measurement region 14 at the farthest position from the center of the setter 10 do. In the case of the firing setter 10, there are four measurement positions 22. Samples 1 and 1a are obtained from the measurement position 22. Even if the shape of the firing setter is a shape whose outer edge is a curved surface such as a polygon other than a quadrangle, a circle, an ellipse, etc., the acquisition position is determined in the same manner. The distance D12 is set to 20 mm when the distance from the center of gravity of the firing setter to the side is 50 mm or more. In addition, when the distance from the center of gravity to the side is less than 50 mm, the distance D12 is 20% of the distance from the center of gravity to the side.

Example

A coating layer was formed on the surface of the substrate under various conditions to prepare a firing setter. The firing setter was repeatedly subjected to a heating test to evaluate the state of the coating layer (presence or absence of peeling and expansion).

Fig. 5 shows the conditions for forming the coating layer, the ratio of the height difference (thickness T1 / thickness T2 x 100) of the obtained coating layer, the area ratio, and the result of the repeated heating test. The ratio of the height difference is an average value of the height difference ratios of the respective regions calculated by dividing the region (1200 占 퐉) observed by the SEM into three regions and calculating the ratio of the height difference for each region (see Fig. 6).

The coating layer was fixed on the surface of the base material by applying a coating material (slurry for coating) on the surface of the base material by using a spray coating method and firing at 1300 캜 for 2 hours. As the coating slurry, a slurry containing a Zr compound having a particle diameter of 10 to 20 mu m was used. The coating layer was formed by spraying a coating material onto a substrate using a spray gun (W-101 manufactured by ANEST IWA TAI. CO., LTD.).

In Examples 1 to 7, a coating layer was formed by largely (100 mm or more) the distance (installation distance) from the substrate to the discharge port of the spray gun so as to form a difference in height in the coating layer. In Examples 1 to 7, the discharge amount and the air amount of the slurry for coating were changed to change the state of the coating layer (ratio of height difference). The discharge amount and the air amount of the coating slurry were adjusted by the number of revolutions of the nozzle (the more the number of revolutions shown in Fig. 5, the larger the discharge amount and the air amount). In Comparative Examples 1 to 3, a coating layer was formed by reducing the distance (50 mm) from the substrate to the discharge port of the spray gun so as to form a coating layer having a small difference in height (smooth surface). In Comparative Examples 1 to 3, the discharge amount of the slurry for coating was changed to change the state of the coating layer (ratio of height difference). 6 shows SEM images of the firing setters of Example 1 and Comparative Example 1. As shown in Fig. As apparent from Fig. 6, the sample of Example 1 has a large difference in height of the coating layer as compared with the sample of Comparative Example 1. Although the illustration is omitted, it was confirmed that the samples of Examples 2 to 7 had a large difference in height of the coating layer, and the samples of Comparative Examples 2 and 3 had a small difference in height of the coating layer.

In the repeated heating test, five cycles were carried out by heating each of the samples up to 1350 占 폚 at a heating rate of 100 占 폚 / hour, holding them at 1350 占 폚 for 2 hours, and then naturally cooling them to room temperature. After completion of each cycle, the outer appearance of the firing setter was observed, and the presence or absence of peeling and expansion of the coating layer was evaluated. "A" indicates that no peeling / swelling of the coating layer was observed, "B" indicates that the peeling / swelling was not observed, and "C" indicates that the peeling / swelling was confirmed .

As shown in Fig. 5, even in the samples (Examples 1 to 7) in which the ratio of the height difference of the coating layer was 40% or less, peeling and expansion of the coating layer were not observed even after 5 cycles of the repeated heating test. On the other hand, in all of the samples of Comparative Examples 1 to 3 (57%, 66%, and 52% of the height difference ratio), signs of peeling and expansion of the coating layer were confirmed at the end of one cycle, or peeling and swelling were actually observed. When the area ratio exceeds 70%, the ratio of the height difference tends to increase. From the results of this embodiment, it can be understood that the firing setter having a high level difference ratio (thickness T1 / thickness T2) of the coating layer within a small range (arbitrary section within a range of 400 占 퐉 占 400 占 퐉) of not more than 40% It was confirmed that peeling and swelling hardly occur.

Although specific embodiments of the present invention have been described in detail, they are illustrative only and do not limit the scope of the claims. The techniques described in the claims include various modifications and changes to the specific examples described above. In addition, the technical elements described in the present specification or drawings exert their technical usefulness solely or in various combinations, and are not limited to the combination of claims described in the application. Further, the techniques exemplified in the present specification or drawings can achieve a plurality of objectives at the same time, and achieving one of them is technically useful.

2: substrate
4: Coating layer
10: Firing setter

Claims (5)

As a firing setter having a coating layer on a substrate,
The coating layer is exposed on the surface of the firing setter,
Wherein a thickness T1 of a minimum thickness portion and a thickness T2 of a maximum thickness portion of a coating layer at an arbitrary cross section in a 400 占 퐉 400 占 퐉 plane satisfy the following formula (1).
T1 / T2? 0.4 (1) The firing setter according to claim 1, further satisfying the following formula (2).
0.05? T1 / T2 (2) And a second plane perpendicular to the thickness direction of the coating layer and including a surface of the coating layer of the maximum thickness portion, the second plane being perpendicular to the thickness direction of the coating layer and including the back surface of the coating layer of the minimum thickness portion, Wherein the ratio of the coating layer occupied by the coating layer is 70% or less. And a second plane perpendicular to the thickness direction of the coating layer and including a surface of the coating layer of the maximum thickness portion, the second plane being perpendicular to the thickness direction of the coating layer and including the back surface of the coating layer of the minimum thickness portion, Wherein the ratio of the coating layer occupied by the coating layer is 70% or less. The firing setter according to any one of claims 1 to 4, wherein an intermediate layer having a coefficient of thermal expansion larger than that of the base material and smaller in thermal expansion coefficient than the coating layer is formed between the base material and the coating layer.

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