Setter for firing

Abstract

A setter for firing according to the present invention is formed by providing a mullite-containing layer that includes mullite on an SiC substrate. The cordierite content of the mullite-containing layer is 3–50 mass% and / or the potassium content of the mullite-containing layer is 1–5 mass%.

Description

Firing setter

[0001] This specification discloses technology relating to a setter for firing.

[0002] Japanese Patent Publication No. 2012-056831 (hereinafter referred to as Patent Document 1) discloses a firing setter for placing an object to be fired during firing. The firing setter of Patent Document 1 has an intermediate layer mainly composed of mullite on a SiC substrate, and a coating layer is provided on the intermediate layer. The intermediate layer is provided as a bonding layer to bond the substrate and the coating layer. The firing setter of Patent Document 1 is mainly used for firing ceramic electronic components.

[0003] The firing setter described in Patent Document 1 has a strong bond between the substrate and the coating layer by an intermediate layer, so the coating layer does not usually peel off even with repeated use. However, when firing certain materials, the coating layer may peel off earlier than usual. The firing setter described in Patent Document 1 does not necessarily experience premature peeling of the coating layer, but its versatility is low because it is limited to materials that can be fired. Therefore, this specification aims to provide a firing setter with high versatility.

[0004] The first technology disclosed herein is a firing setter, wherein a mullite-containing layer containing mullite is provided on a SiC substrate, and the mullite-containing layer may satisfy at least one of the following conditions: the cordierite contained in the mullite-containing layer is 3% by mass or more and 50% by mass or less, and the potassium element contained in the mullite-containing layer is 1% by mass or more and 5% by mass or less.

[0005] The second technology disclosed herein is a firing setter of the first technology described above, wherein a coating layer may be provided on the surface of the mullite-containing layer.

[0006] The third technology disclosed herein is a firing setter of the second technology described above, wherein the coating layer may have a first coating layer in contact with the mullite-containing layer and a second coating layer forming the surface layer of the firing setter.

[0007] The fourth technology disclosed herein is a firing setter of any of the first to third technologies described above, wherein the mullite-containing layer may contain 3% by mass or more and 40% by mass or less of alumina.

[0008] The fifth technology disclosed herein is a firing setter, wherein a mullite-containing layer containing mullite is provided on a SiC substrate, and the mullite-containing layer may contain 1% to 50% by mass of cordierite, 1% to 4% by mass of potassium, and 3% to 40% by mass of alumina.

[0009] The sixth technology disclosed herein is a firing setter of the fifth technology described above, wherein a coating layer may be provided on the surface of the mullite-containing layer.

[0010] The seventh technology disclosed herein is a firing setter of the sixth technology described above, wherein the coating layer may have a first coating layer in contact with the mullite-containing layer and a second coating layer forming the surface layer of the firing setter.

[0011] The eighth technology disclosed herein is a firing setter of the first to seventh technologies described above, wherein when the mullite-containing layer is measured using an X-ray diffractometer, the ratio of the peak integral intensity value of cordierite at a 2θ angle to the peak integral intensity value of mullite at a 2θ angle may be 0.17 to 3.

[0012] The ninth technology disclosed herein is a firing setter of the first to eighth technologies described above, wherein when a workpiece containing a sodium component is placed on its surface and fired, a compound of Si and Na may be formed in the mullite-containing layer.

[0013] A schematic diagram of the firing setter is shown. A diagram illustrating the distribution of cordierite within the mullite-containing layer is shown. SiO within the mullite-containing layer ２ A diagram illustrating the distribution is shown. A schematic diagram of a conventional firing setter is shown. The results of the experimental example are shown. The results of the experimental example are shown. The results of the experimental example are shown. The results of the experimental example are shown.

[0014] The setter for firing disclosed in this specification is used for placing an object to be fired such as an electronic component or a ceramic member when firing the object to be fired. As described above, when firing a specific object to be fired, a phenomenon in which the coating layer peels off earlier than usual has been confirmed in the conventional setter for firing. Here, referring to FIG. 4, the conventional setter for firing 110 will be described.

[0015] The setter for firing 110 includes a SiC substrate 102 containing Si, a mullite layer (intermediate layer) 104 provided on the SiC substrate 102, and two coating layers 106 and 108 provided on the mullite layer 104. The coating layer 106 is made of alumina and is in contact with the mullite layer 104. The coating layer 108 is made of zirconia and forms the surface layer of the setter for firing 110. Note that, at the interface between the SiC substrate 102 and the mullite layer 104, there is a SiO ２ layer 20 formed. The SiO ２ layer 20 is an oxide film of Si formed on the surface of the SiC substrate 102 during the manufacturing process (firing process) of the setter for firing 110.

[0016] When the setter for firing 110 is repeatedly used for firing a specific object to be fired, it has been confirmed that the coating layers 106 and 108 peel off earlier than usual. When analyzing the used setter for firing 110, it has been confirmed that the mullite layer 104 contains a large amount of sodium. Sodium is mainly confirmed to be unevenly distributed at the interface between the SiC substrate 102 and the mullite layer 104 (near the SiO ２ layer 20).

[0017] Sodium is a component contained in the object to be fired. Therefore, during the firing of the object to be fired, sodium penetrates from the object to be fired into the mullite layer 104 and reacts with the SiO ２ layer 20, presumably altering the SiO ２ layer 20. Specifically, it is presumed that sodium melts the SiO ２ of the SiO ２ layer 20, and agglomerated SiO ２ is formed at the interface between the SiC substrate 102 and the mullite layer 104. The agglomerated SiO ２As a result of this formation, the mullite layer 104 is unable to relieve the stress caused by the thermal expansion coefficients of the SiC substrate 102 and the coating layers 106 and 108. Consequently, it is presumed that delamination occurred between the SiC substrate 102 and the mullite layer 104, leading to the premature delamination of the coating layers 106 and 108.

[0018] The firing setter disclosed herein is used on a SiC substrate and contains mullite (2Al ２ O ３ -SiO ２ A mullite-containing layer containing cordierite (MgO-Al) is provided, and the mullite-containing layer satisfies at least one of the following conditions (1) and (2). Condition (1): The mullite-containing layer contains cordierite (MgO-Al) ２ O ３ -SiO ２ (2) The amount of potassium (K) in the mullite-containing layer is 3% by mass or more and 50% by mass or less.

[0019] A firing setter that satisfies the above condition (1) can suppress the uneven distribution of sodium (Na) at the interface between the SiC substrate and the mullite-containing layer, as sodium (Na) that has penetrated the mullite-containing layer is adsorbed onto cordierite. In other words, SiO present at the interface between the SiC substrate and the mullite-containing layer ２ The alteration of the layer by sodium is suppressed, and SiO is aggregated at the interface between the SiC substrate and the mullite-containing layer. ２ The formation of [unclear] can be suppressed. As a result, a firing setter that satisfies condition (1) can suppress the premature peeling of the mullite-containing layer from the SiC substrate, even when used for firing a workpiece containing sodium. The proportion of cordierite in the mullite-containing layer may be 10% by mass or more, 25% by mass or more, 30% by mass or more, or 40% by mass or more. Alternatively, the proportion of cordierite in the mullite-containing layer may be 40% by mass or less, 30% by mass or less, 25% by mass or less, or 10% by mass or less.

[0020] The firing setter disclosed herein may satisfy the following condition (3) in addition to or instead of the above condition (1). Condition (3): When the mullite-containing layer is measured using an X-ray diffractometer, the ratio of the peak integral intensity value of cordierite at a 2θ angle to the peak integral intensity value of mullite at a 2θ angle is 0.17 to 3.

[0021] The mullite-containing layer may contain substances other than mullite and cordierite. Therefore, depending on the type of substance contained in the mullite-containing layer, it may be difficult to directly measure the amount of cordierite contained in the mullite-containing layer. By measuring the mullite-containing layer using the method described in condition (3) above, it is possible to determine whether the mullite-containing layer contains enough cordierite to adequately adsorb the sodium that has permeated into the mullite-containing layer.

[0022] A firing setter that satisfies the above condition (2) is one in which potassium elements are present at the interface between the SiC substrate and the mullite-containing layer. ２ The layer has a lower melting point. And in the manufacturing process of the setter for firing (firing process), SiO ２ The layer is dispersed throughout the mullite-containing layer. That is, a firing setter that satisfies condition (2) has SiO at the interface between the SiC substrate and the mullite-containing layer. ２ The layer does not segregate. Therefore, even when a firing setter that satisfies condition (2) is used to fire a workpiece containing sodium, the SiO that aggregates at the interface between the SiC substrate and the mullite-containing layer does not segregate. ２ This prevents the formation of a mullite-containing layer and suppresses the premature peeling of the mullite-containing layer from the SiC substrate. Note that the potassium element is potassium carbonate (K ２ CO ３ ), potassium oxide (K ２ Oxides such as potassium nitride (K ３Potassium may be present in the mullite-containing layer in the form of nitrides such as N. The proportion of potassium element in the mullite-containing layer may be 2% by mass or more, 3% by mass or more, or 4% by mass or more. Furthermore, the proportion of potassium element in the mullite-containing layer may be 4% by mass or less, 3% by mass or less, or 2% by mass or less.

[0023] Furthermore, the firing setter disclosed herein does not need to completely prevent sodium from reaching the interface between the SiC substrate and the mullite-containing layer when firing an object containing sodium. For example, when an object containing sodium is placed on the surface of the firing setter and fired, a Si-Na compound may be formed in the mullite-containing layer. An example of a Si-Na compound is nepheline (Na ３ K (Al ４ Si ４ O １６ ), NaAlSiO ４ ) are examples. When nepheline is formed in the mullite-containing layer, the movement of the sodium component to the SiC-based substrate side is suppressed by the nepheline. The Si and Na compound formed in the mullite-containing layer is preferably 0.1% by mass or more, and more preferably 0.3% by mass or more. The mass ratio of the Si and Na compound can be measured using EDS (Energy Dispersive X-ray Spectroscopy).

[0024] Furthermore, the firing setter disclosed herein may further contain 3% to 40% by mass of alumina in the mullite-containing layer. By containing 3% to 40% by mass of alumina in the mullite-containing layer, peeling of the mullite-containing layer can be further suppressed. The proportion of alumina in the mullite-containing layer may be 5% by mass or more, 10% by mass or more, 25% by mass or more, or 30% by mass or more. Alternatively, the proportion of alumina in the mullite-containing layer may be 30% by mass or less, 25% by mass or less, 10% by mass or less, or 5% by mass or less.

[0025] Note that the SiC-based substrate means a substrate in which SiC contained in the substrate is 50% by mass or more, and examples of the substrate include those mainly composed of SiC, Si-SiC, etc. Further, "Si-SiC" means a material mainly composed of SiC particles (50% by mass or more of the whole) and containing metallic Si between the SiC particles.

[0026] The setter for firing disclosed in this specification may have only a mullite-containing layer provided on the SiC-based substrate, or a coating layer may be provided on the surface of the mullite-containing layer. When only the mullite-containing layer is provided on the SiC-based substrate, the mullite-containing layer is exposed on the surface of the setter for firing, and the mullite-containing layer serves as the placement surface for the object to be fired.

[0027] The coating layer may be a single layer or a plurality of layers formed of different materials. Specifically, it may have a first coating layer in contact with the mullite-containing layer and a second coating layer forming the surface layer of the setter for firing. Further, one or more coating layers may be provided between the first coating layer and the second coating layer. The coating layer may be formed of alumina, mullite, zirconia, and yttria, or a material containing a plurality of these.

[0028] The setter for firing disclosed in this specification has a mullite-containing layer containing mullite provided on the SiC-based substrate, and the mullite-containing layer may contain cordierite of 1% by mass or more and 50% by mass or less, potassium element of 1% by mass or more and 4% by mass or less, and alumina of 3% by mass or more and 40% by mass or less. That is, all of cordierite, potassium element, and alumina may be contained in the mullite-containing layer. By adjusting the ratios of cordierite, potassium element, and alumina contained in the mullite-containing layer within the above ranges, even when used for firing an object to be fired containing sodium, it is possible to suppress the early peeling of the mullite-containing layer from the SiC-based substrate.

[0029] Referring to Figure 1, the firing setter 10 will be described. The firing setter 10 comprises a Si-SiC substrate 2, a mullite-containing layer 4 provided on the surface of the substrate 2, a first coating layer 6 provided on the surface of the mullite-containing layer 4 (the side opposite to the substrate 2), and a second coating layer 8 provided on the surface of the first coating layer 6.

[0030] The mullite-containing layer 4 contains mullite, with 25% by mass of cordierite and 10% by mass of alumina. The first coating layer 6 is made of alumina and is in contact with the surface of the mullite-containing layer. The second coating layer 8 is made of zirconia and is in contact with the surface of the first coating layer 6, as well as forming the surface of the firing setter 10. In the firing setter 10, the object to be fired is placed on the surface of the second coating layer 8.

[0031] Figure 2 shows an enlarged view of the mullite-containing layer 4. Cordierite 12 is dispersed within the mullite-containing layer 4. Also, at the interface between the substrate 2 and the mullite-containing layer 4, SiO is formed from oxidized Si contained in the substrate 2. ２ Layer 20 is formed. Although not shown in the diagram, alumina is also dispersed within the mullite-containing layer 4. When sodium contained in the material being fired penetrates into the mullite-containing layer 4 during firing, cordierite 12 adsorbs the sodium. As a result, the sodium that has penetrated into the mullite-containing layer 4 does not segregate at the interface between the substrate 2 and the mullite-containing layer 4, and instead aggregates at the interface between the substrate 2 and the mullite-containing layer 4. ２ This suppresses the formation of SiO at the interface between the substrate 2 and the mullite-containing layer 4, and prevents the peeling of the mullite-containing layer 4. ２ Layer 20 gradually diffuses throughout the mullite-containing layer 4 while the firing setter 10 is in use (while it is being used to fire the object to be fired).

[0032] The proportions of cordierite and alumina within the mullite-containing layer 4 are not limited to the above proportions. Furthermore, the mullite-containing layer 4 may contain only cordierite and no alumina. Alternatively, the mullite-containing layer 4 may contain potassium element and no cordierite. The following describes the combinations of substances and their proportions within the mullite-containing layer 4: (a) Cordierite: 3% to 50% by mass (b) Cordierite: 3% to 50% by mass, Alumina: 3% to 40% by mass (c) Potassium element: 1% to 5% by mass (d) Potassium element: 1% to 5% by mass, Alumina: 3% to 40% by mass (e) Cordierite: 1% to 50% by mass, Potassium element: 1% to 4% by mass, Alumina: 3% to 40% by mass

[0033] In (a), (b), and (e) above, in addition to the condition "cordierite: 3% by mass or more and 50% by mass or less", or instead of the condition "cordierite: 3% by mass or more and 50% by mass or less", the condition "when the mullite-containing layer is measured using an X-ray diffractometer, the ratio of the peak integral intensity value of cordierite at a 2θ angle to the peak integral intensity value of mullite at a 2θ angle is 0.17 to 3" may also be satisfied.

[0034] The amounts of cordierite, alumina, and potassium contained in the mullite-containing layer 4 can be calculated using an X-ray diffractometer (XRD) and an energy-dispersive X-ray spectroscopy (EDX), etc.

[0035] Referring to Figure 3, the case in which potassium is present in the mullite-containing layer 4 (corresponding to (c), (d), and (e) above) will be explained. When potassium is present in the mullite-containing layer 4, SiO is formed at the interface between the substrate 2 and the mullite-containing layer 4. ２ The melting point of the layer decreases. As a result, in the manufacturing process (firing process) of the firing setter 10, SiO ２The layer diffuses throughout the mullite-containing layer 4. Therefore, when the firing setter 10 is completed, the SiO formed at the interface between the substrate 2 and the mullite-containing layer 4 ２ The layer has disappeared, and SiO is present at the interface between the substrate 2 and the mullite-containing layer 4. ２ The layer does not clump together, and the peeling of the mullite-containing layer 4 can be suppressed.

[0036] (Experimental Example) An accelerated test was conducted by changing the substances contained in the mullite-containing layer 4 of the firing setter 10. Specifically, in the accelerated test, multiple samples were prepared in which the ratios of cordierite, potassium element, and alumina contained in the mullite-containing layer 4 were changed. A sodium-containing solution was applied to each sample, and a heating test was performed in two cycles, with one cycle consisting of heating at 1250°C for 3 hours followed by cooling to room temperature. The sodium-containing solution was sodium bicarbonate (NaHCO3). ３ A sodium bicarbonate suspension was used, which was prepared by adding water to finely powdered sodium bicarbonate and stirring with a stirrer for at least 30 minutes. The sodium-containing solution was applied to each sample by dropping the sodium bicarbonate suspension onto the surface of each sample while stirring the sodium bicarbonate suspension with a stirrer.

[0037] In addition, each sample in the accelerated heating test was visually inspected. Samples in which delamination occurred in the mullite-containing layer 4 after one heating cycle were deemed unsuccessful ("D"). Samples in which no delamination occurred in the mullite-containing layer 4 after one heating cycle, but cracks were observed in the mullite-containing layer 4, were deemed acceptable ("C"). Samples in which no delamination or cracks occurred in the mullite-containing layer 4 after one heating cycle, and no delamination occurred in the mullite-containing layer 4 after two heating cycles, but cracks were observed in the mullite-containing layer 4, were deemed acceptable ("B"). Samples in which no delamination or cracks occurred in the mullite-containing layer 4 after two heating cycles were deemed acceptable ("A").

[0038] Figure 5 shows the results of varying the ratio of cordierite and alumina contained in the mullite-containing layer 4 (samples 1 to 29). For samples 1 to 29, the mullite-containing layer 4 was measured using an X-ray diffractometer (Rigaku Corporation: SmartLab SE) before the accelerated test. The measurement conditions for the mullite-containing layer 4 are as follows: Tube voltage: 40 kV; Tube current: 30 mA; Measurement range of sealed tube copper: 10° to 60°; Step: 0.0100°; Speed: 10.0° / min.

[0039] Figure 5 shows the ratio (X-ray intensity ratio) of the peak integral intensity value of cordierite at a 2θ angle to the peak integral intensity value of mullite at a 2θ angle. Samples 1 to 29 did not contain added potassium. As shown in Figure 5, all samples (samples 1, 2, 8-11) in which the proportion of cordierite in the mullite-containing layer 4 was outside the range of 3% to 50% by mass were rejected (evaluation D). On the other hand, all samples (samples 3-7, 12-29) in which the mullite-containing layer 4 contained 3% to 50% by mass of cordierite were confirmed to be at an acceptable level (evaluation A-C). Furthermore, it was confirmed that all samples 3-7 and 12-29 had an X-ray intensity ratio of 0.17 to 3. In particular, samples containing 3% to 40% by mass of cordierite (samples 3-6, 12-14, 16, 17, 19-21, 23-25, 27, 28) yielded good results (rating A or B). Furthermore, comparing samples 6, 17, and 21, it was confirmed that samples with 10% or 30% by mass of alumina added (samples 20, 21, 24, 25) showed further improved properties (rating A).

[0040] Figure 6 shows the results of varying the proportions of potassium and alumina contained in the mullite-containing layer 4 (samples 31-57). Note that cordierite was not added to samples 31-57. As shown in Figure 6, all samples (samples 31, 37, 38, 44, 45, 49, 53, 57) in which the proportion of potassium in the mullite-containing layer 4 was outside the range of 1% to 5% by mass were unsuccessful (evaluation D). On the other hand, all samples (samples 32-36, 39-43, 46-48, 50-52, 54-56) in which the mullite-containing layer 4 contained 1% to 5% by mass of potassium were confirmed to be at an acceptable level (evaluation A-C). In particular, samples (samples 32-35, 39-42, 46, 47, 50, 51, 54, 55) containing 1% to 4% by mass of potassium yielded good results (evaluation A or B). Furthermore, in samples containing 1% to 4% by mass of potassium, it was confirmed that the properties could be further improved by reducing the alumina content to 10% by mass or less (Samples 32-35, 39-42, 46, 47: Evaluation A).

[0041] Figure 7 shows the results of adding both potassium and cordierite to the mullite-containing layer 4 (samples 61-71). Note that alumina was not added to samples 61-71. As shown in Figure 7, even when the mullite-containing layer 4 contains both potassium and cordierite, it was found that a passing level (evaluation A-C) result can be obtained if either the condition that the proportion of cordierite in the mullite-containing layer 4 is 3% to 50% by mass, or the condition that the proportion of potassium in the mullite-containing layer 4 is 1% to 5% by mass, is satisfied. For example, samples 62, 66, and 70 do not satisfy the condition that the proportion of cordierite in the mullite-containing layer 4 is 3% to 50% by mass. However, samples 62, 66, and 70 satisfy the condition that the proportion of potassium in the mullite-containing layer 4 is 1% to 5% by mass, and thus obtained passing level characteristics. In particular, combinations containing 1% to 4% by mass of potassium and 1% to 40% by mass of cordierite (samples 62-64, 66-68) yielded excellent results (evaluation A or B).

[0042] Figure 8 shows the results of varying the proportions of cordierite, potassium, and alumina contained in the mullite-containing layer 4 (samples 81-101). As shown in Figure 8, all samples (samples 81, 87, 93, 98, 103) that did not satisfy the requirements of having a cordierite proportion of 1% to 50% by mass, a potassium proportion of 1% to 4% by mass, and an alumina proportion of 3% to 40% by mass in the mullite-containing layer 4 were rejected (evaluation D). On the other hand, all samples (samples 82-86, 88-92, 94-97, 99-102, 104-106) that contained 1% to 50% by mass of cordierite, 1% to 4% by mass of potassium, and 3% to 40% by mass of alumina in the mullite-containing layer 4 were confirmed to be at an acceptable level (evaluation A-C). In particular, samples containing 1% to 30% by mass of cordierite (samples 82-85, 88-91, 94-97, 99-102, 104, and 105) yielded good results (evaluation A or B). Furthermore, comparing the results of evaluation A and B, it was confirmed that samples containing 1% to 20% by mass of cordierite (samples 82-84, 88-90, 94-96, and 99-101) showed further improvement in properties (evaluation A).

[0043] Although specific examples of the present invention have been described in detail above, these are merely illustrative and do not limit the scope of the claims. The technologies described in the claims include various modifications and changes to the specific examples illustrated above. Furthermore, the technical elements described in this specification or drawings exhibit technical usefulness individually or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technologies illustrated in this specification or drawings can achieve multiple objectives simultaneously, and achieving even one of these objectives itself constitutes technical usefulness.

[0044] 2: SiC substrate 4: Mullite-containing layer 6: First coating layer 8: Second coating layer 10: Setter for firing

Claims

1. A firing setter comprising a mullite-containing layer on a SiC substrate, wherein the mullite-containing layer satisfies at least one of the following conditions: the cordierite contained in the mullite-containing layer is 3% by mass or more and 50% by mass or less, and the potassium element contained in the mullite-containing layer is 1% by mass or more and 5% by mass or less.

2. The firing setter according to claim 1, wherein a coating layer is provided on the surface of the mullite-containing layer.

3. The firing setter according to claim 2, wherein the coating layer comprises a first coating layer in contact with the mullite-containing layer and a second coating layer forming the surface layer of the firing setter.

4. A firing setter according to any one of claims 1 to 3, wherein the mullite-containing layer contains 3% by mass or more and 40% by mass or less of alumina.

5. A setter for firing, comprising a mullite-containing layer on a SiC substrate, wherein the mullite-containing layer contains 1% to 50% by mass of cordierite, 1% to 4% by mass of potassium, and 3% to 40% by mass of alumina.

6. The firing setter according to claim 5, wherein a coating layer is provided on the surface of the mullite-containing layer.

7. The firing setter according to claim 6, wherein the coating layer comprises a first coating layer in contact with the mullite-containing layer and a second coating layer forming the surface layer of the firing setter.

8. The firing setter according to any one of claims 1 to 3, wherein when the mullite-containing layer is measured using an X-ray diffractometer, the ratio of the peak integral intensity value of cordierite at a 2θ angle to the peak integral intensity value of mullite at a 2θ angle is 0.17 to 3.

9. A firing setter according to any one of claims 1 to 3, wherein when a workpiece containing sodium is placed on its surface and fired, a compound of Si and Na is formed in the mullite-containing layer.

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