Method for inspecting the amount of adhesive powder and method for manufacturing ceramic substrates using the same.

Abstract

Provided is an inspection method for inspecting the amount of a floor powder adhered on a ceramic molded article. Also provided is a method for producing a ceramic substrate using the inspection method. The method for inspecting the amount of a floor powder adherence according to an embodiment comprises an adhesion step and an inspection step. In the adhesion step, a floor powder is adhered on to the surface of a ceramic molded article. In the inspection method, reflected light or transmitted light on the surface is detected using a photoelectric sensor or an image sensor to inspect the amount of the adhered floor powder.

Description

Technical Field

[0001] The embodiments described below generally relate to a method for inspecting the amount of dusting powder adhered and a method for manufacturing a ceramic substrate using the same.

Background Art

[0002] Ceramic substrates are used as circuit boards for mounting semiconductor elements. Various ceramic substrates such as silicon nitride substrates, aluminum nitride substrates, aluminum oxide substrates, zirconium oxide substrates, and alumina zirconia substrates are used. An alumina zirconia substrate is a mixture of zirconium oxide and aluminum oxide. The alumina zirconia substrate is sometimes referred to as an aldyl substrate.

[0003] The manufacturing process of a ceramic substrate includes a raw material mixing process, a forming process, a debinding process, a sintering process, etc. In the raw material mixing process, raw material powder and an organic binder are mixed to prepare a raw material paste. In the forming process, a sheet-shaped molded body is prepared from the raw material paste. In the debinding process, the binder is removed from the sheet-shaped molded body. In the sintering process, the sheet-shaped molded body after debinding is sintered. The sheet-shaped molded body has been cut to a predetermined size and then the debinding process and the sintering process are performed. In the sintering process, in order to improve the manufacturing efficiency, the sheet-shaped molded bodies are laminated. When laminating the molded bodies, dusting powder is used. By using dusting powder, it is possible to prevent the sheet-shaped molded bodies from bonding to each other.

[0004] For example, in Japanese Patent No. 5339214 (Patent Document 1), the particle size and the adhesion amount of the dusting powder are controlled. By controlling the adhesion amount of the dusting powder, etc., the undulation on the surface of the ceramic substrate is reduced.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

[0006] As described in Patent Document 1, the amount of powder applied can be controlled to reduce surface irregularities on ceramic substrates. However, when the processing volume (increased production volume of ceramic substrates, larger sheets, etc.) increases, a decrease in yield occurs. Upon investigating the cause, it was found that the cause lies in the variation in the amount of powder applied to the ceramic molded body. For example, in Patent Document 1, the powder is applied by spraying. In Japanese Utility Model Publication No. 10-84 (Patent Document 2), the powder is applied using a brush or similar tool. The powder is a small powder with an average particle size of 20 μm or less. In recent years, sheet-like molded bodies before cutting have become larger and longer. Also, in order to increase production efficiency, powder is sometimes applied while the sheet-like molded body is moved. As a result, uneven application of the powder occurs. Even if uneven application of the powder occurs, it is difficult to discern with the naked eye. If the sintering process is carried out with uneven application, ceramic substrates with large surface irregularities can be manufactured.

[0007] The embodiment is intended to address these issues and to provide a method for inspecting the amount of powder adhering to a ceramic molded body. [Means for solving the problem]

[0008] The method for inspecting the amount of powder adhering to a surface according to the embodiment comprises an adhesion step and an inspection step. In the adhesion step, powder is applied to the surface of a ceramic molded body. In the inspection step, the amount of powder adhering is inspected by detecting reflected or transmitted light from the surface using a photoelectric sensor or an image sensor. [Brief explanation of the drawing]

[0009] [Figure 1]A flowchart illustrating an example of a method for inspecting the amount of bedding powder adhering to a given surface according to this embodiment. [Figure 2] A figure showing an example of a ceramic molded body according to the embodiment. [Figure 3] A diagram illustrating an example of a method for applying bedding powder using a spray method. [Figure 4] A diagram illustrating an example of a method for inspecting the amount of bedding powder adhering to the surface. [Figure 5] A flowchart illustrating a method for manufacturing a ceramic substrate according to an embodiment. [Figure 6] A figure showing an example of a method for manufacturing a ceramic substrate according to the embodiment. [Modes for carrying out the invention]

[0010] The method for inspecting the amount of powder adhering to a surface according to the embodiment comprises an adhesion step and an inspection step. In the adhesion step, powder is applied to the surface of a ceramic molded body. In the inspection step, the amount of powder adhering is inspected by detecting reflected or transmitted light from the surface using a photoelectric sensor or an image sensor.

[0011] Figure 1 is a flowchart showing an example of a method for inspecting the amount of bedding powder attached according to an embodiment. As shown in Figure 1, the method M1 for inspecting the amount of bedding powder attached according to an embodiment comprises an attachment step P1 for attaching bedding powder to a ceramic molded body, and an inspection step P2 for inspecting the amount of bedding powder attached.

[0012] Figure 2 shows an example of a ceramic molded body according to the embodiment. In Figure 2, reference numeral 1 denotes the ceramic molded body, and reference numeral 2 denotes the surface of the ceramic molded body 1. First, prepare the ceramic molded body 1 shown in Figure 2. The ceramic molded body 1 is formed from ceramic powder. Organic binders and the like may be added to the ceramic molded body 1 as needed. The shape of the ceramic molded body 1 is not particularly limited and may be sheet-shaped, circular, or have an uneven surface. Hereafter, a sheet-shaped ceramic molded body 1 will be described as an example.

[0013] The ceramic molded body 1 mainly consists of one of the following: silicon nitride, aluminum nitride, aluminum oxide, zirconium oxide, and silicon carbide. The main component is the most abundant component in the ceramic sintered body. For example, a ceramic molded body 1 mainly composed of silicon nitride becomes a silicon nitride sintered body after sintering. A ceramic molded body 1 mainly composed of aluminum oxide becomes an aluminum oxide sintered body after sintering.

[0014] When two or more elements selected from silicon nitride, aluminum nitride, aluminum oxide, zirconium oxide, and silicon carbide are mixed, the element with the highest concentration is considered the main component. For example, Argil sintered bodies are a mixture of aluminum oxide and zirconium oxide. If aluminum oxide is the most abundant element in the Argil sintered body, it will become an aluminum oxide sintered body after sintering. Ceramic sintered bodies may also contain sintering aids in addition to the main component.

[0015] Methods for manufacturing the ceramic molded body 1 include the doctor blade method, mold molding, cold isostatic pressing (CIP), and injection molding. As will be described later, the doctor blade method is preferred when manufacturing ceramic substrates. The ceramic molded body 1 is subjected to a degreasing process as needed. In other words, a degreased body that has undergone the degreasing process is also included in the ceramic molded body 1. The degreasing process may be performed before the base powder is attached to the ceramic molded body 1, or after the base powder is attached to the ceramic molded body 1.

[0016] Next, an adhesion step P1 of adhering dusting powder is performed on the surface 2 of the prepared ceramic molded body 1. Methods of adhering dusting powder include a method using a spray, a method of passing the ceramic molded body 1 through a solution in which the dusting powder is dispersed, a method using a brush, a method using static electricity, a method using gravure printing, a method of dipping the ceramic molded body 1 in a solution containing the dusting powder, and the like. As will be described later, when the ceramic molded body 1 is used as a ceramic substrate, the method using a spray is preferred. In the case of the spray method, the injection amount of the dusting powder can be stabilized. The spray method includes a method of injecting only the dusting powder and a method of injecting a solution in which the dusting powder is dispersed. As the spray method, a method of injecting a solution in which the dusting powder is dispersed is more preferred. By previously dispersing the dusting powder in the solution, aggregation of the dusting powder can be suppressed.

[0017] FIG. 3 is a diagram showing an example of a method of adhering dusting powder using a spray method. In FIG. 3, reference numeral 3 is a dusting powder adhesion layer, reference numeral 5 is a spray, and reference numeral 6 is dusting powder. FIG. 3 shows an example in which the spray 5 is injecting the dusting powder 6 from above the ceramic molded body 1. As shown in FIG. 3, the spray 5 may inject the dusting powder 6 directly above the ceramic molded body 1 or may inject the dusting powder 6 obliquely above the ceramic molded body 1. Also, in the example shown in FIG. 3, one spray 5 is injecting the dusting powder 6, but a plurality of sprays 5 may each inject the dusting powder 6.

[0018] The dusting powder 6 is one or more kinds of powders selected from boron nitride, zirconium oxide, aluminum oxide, and aluminum nitride. When the dusting powder 6 adheres to the surface 2 of the ceramic molded body 1, the dusting powder adhesion layer 3 is formed. The dusting powder adhesion layer 3 serves to prevent the ceramic sintered bodies from bonding when a plurality of ceramic molded bodies 1 are laminated and sintered. That is, for the dusting powder 6, a powder that does not bond to the ceramic sintered body is used in the sintering process of the ceramic sintered body.

[0019] The coating powder 6 is preferably a boron nitride powder. As described later, the ceramic green body 1 is sintered at 1600 to 2000 °C to produce a ceramic sintered body. Boron nitride is difficult to bond with the ceramic sintered body even in a high-temperature environment. The structure of boron nitride varies, such as hexagonal, cubic, and rhombohedral. Among these, hexagonal boron nitride is preferred. Hexagonal boron nitride may also be denoted as h-BN.

[0020] The average particle size of the coating powder 6 is preferably 20 μm or less. By reducing the average particle size, it becomes easier to form a coating powder adhesion layer 3 with a uniform film thickness on the surface 2 of the ceramic green body 1. If the average particle size exceeds 20 μm and is large, the film thickness of the coating powder adhesion layer 3 becomes non-uniform, which may have an adverse effect on the surface properties of the ceramic sintered body. Therefore, the average particle size of the coating powder 6 is preferably 20 μm or less. The average particle size of the coating powder is more preferably 10 μm or less, and even more preferably 6 μm or less. The lower limit of the average particle size of the coating powder 6 is not particularly limited, but 2 μm or more is preferred. If the average particle size is less than 2 μm, the handling property may deteriorate.

[0021] Next, an inspection process P2 for inspecting the adhesion amount of the coating powder 6 on the surface 2 of the ceramic green body 1 is performed. In the inspection process, the adhesion amount of the coating powder 6 is inspected by detecting the reflected light or transmitted light on the surface by a photoelectric sensor or an image sensor.

[0022] The photoelectric sensor includes a light emitting part that emits light and a light receiving part that receives light. The light emitted from the light emitting part is irradiated onto the ceramic green body 1 on which the coating powder adhesion layer 3 is formed. When a reflection type photoelectric sensor is used, the light reflected from the surface 2 of the ceramic green body 1 on which the coating powder adhesion layer 3 is formed is detected by the light receiving part. When a transmission type photoelectric sensor is used, the light transmitted through the ceramic green body 1 on which the coating powder adhesion layer 3 is formed is detected by the light receiving part. Infrared rays, lasers, etc. are used for the light of the light emitting part. The wavelength of infrared rays is longer than the wavelength of visible light. Monochromatic visible light is used for the laser. When a photoelectric sensor is used, it is preferable to irradiate the coating powder adhesion layer 3 with light and detect the reflected light.

[0023] The image sensor includes a camera and an image processing unit. The camera captures light incident from the object (the surface 2 of the ceramic molded body 1 on which the powder-adhering layer 3 is formed) through an optical system such as a lens, forms an image on the light-receiving surface of the image sensor (image sensor element), and converts it into an electrical signal. This yields image data. The image processing unit detects the characteristic features of the object by processing the data output by the camera. When an image sensor is used, light is shone onto the powder-adhering layer 3, and the reflected light is detected.

[0024] The image sensor is preferably an infrared image sensor or an ultraviolet image sensor. An infrared image sensor is a sensor that detects infrared light (wavelength 780 nm to 1000 μm). An ultraviolet image sensor is a sensor that detects ultraviolet light (wavelength 10 nm to 400 nm). When using an ultraviolet image sensor, a phosphor that emits light when exposed to ultraviolet light may be mixed into the substrate powder. By mixing in a phosphor, the detection accuracy of reflected light can be improved.

[0025] The intensity of light detected by the sensor depends not only on the amount of powder 6 attached, but also on the intensity of the light irradiated onto the ceramic molded body 1. To reduce the influence of variations in the intensity of the irradiated light on the inspection results, it is preferable to use an illumination device in the inspection process. The illumination device emits light of a preset intensity. When an infrared image sensor is used, the illumination device emits infrared light. When an ultraviolet image sensor is used, the illumination device emits ultraviolet light.

[0026] When an image sensor is used, the illumination device that emits light may be either coaxial or reflective. In a coaxial system, the light incident on the object lies on the same optical axis as the light reflected from the object. In a reflective system, the direction of the light illuminating the surface of the object is different from the direction of the light reflected from the object.

[0027] Figure 4 shows an example of a method for inspecting the amount of powder adhering to the surface. In Figure 4, reference numeral 7 denotes a lighting device and reference numeral 8 denotes a sensor. In the example shown in Figure 4, the lighting device 7 irradiates light onto the surface 2 from diagonally above. The sensor 8 detects the light reflected from the surface 2 from directly above. The example is not limited to the example shown in Figure 4; multiple lighting devices 7 may be provided to uniformly illuminate each part of the surface 2.

[0028] Comparing photoelectric sensors and image sensors, image sensors are preferable. Image sensors can detect light over a wide area at once. Comparing infrared image sensors and ultraviolet image sensors, infrared image sensors are preferable. By using infrared light, they are less affected by natural light and indoor light. Also, by using infrared light, they are less affected by shadows of people and objects.

[0029] It is preferable to use edge detection on images generated by detecting reflected or transmitted light. Edge detection is a process for detecting edges from an image and is a type of feature detection. An "edge" is a region between adjacent pixels where the gradient of pixel values ​​(luminance) exceeds a threshold. Pixel values ​​depend on the brightness of the object (intensity of reflected or transmitted light). Points where the change in brightness is large are considered to be points where the shape or material of the object is large. The color of the powder is brighter than the color of the ceramic molded body 1. Therefore, as the amount of powder attached increases, the brightness of the object increases. When the amount of powder attached exceeds a predetermined amount, the color of the ceramic molded body 1 becomes invisible, and the brightness of the object stops changing.

[0030] For example, if the amount of powder adhering to the surface is small, a difference in brightness will occur on the surface of the ceramic molded body 1 between areas with a large amount of powder and areas with a small amount of powder. Therefore, the boundary between the areas with a large amount of powder and areas with a small amount of powder will be detected as an edge. If the overall amount of powder adhering to the surface of the ceramic molded body 1 is insufficient, more edges will be detected. As the amount of powder adhering to the surface of the ceramic molded body 1 increases, the total number of edges detected on the ceramic molded body 1 will decrease. If the overall amount of powder adhering to the surface of the ceramic molded body 1 becomes excessive, the proportion of areas with high brightness will increase, making it more difficult to detect edges.

[0031] In other words, if the amount of powder attached is appropriate, a corresponding brightness is detected. An appropriate brightness range is set, and brightness outside this range is detected as an edge. Brightness outside the range is detected as the number of edges. To put it another way, by attaching the powder to the ceramic molded body 1 so that the brightness falls within that range, the amount of powder attached can be kept within an appropriate range.

[0032] For example, if the target yield is 90% or higher, it is effective to set the target value from data that yields 90% or higher. This method involves setting the brightness of the edges of the ceramic molded body 1 with the burr attached as the target value when a yield of 90% or higher is achieved.

[0033] Furthermore, in the process of inspecting the amount of powder attached using a reflected light detection process, any arbitrary standard can be used to determine the quality of the powder attachment. When the amount of powder attached is inspected using edge detection, edge pixels are detected. If the amount of powder attached is large, the edge pixels will be large, and if the amount of powder attached is small, the edge pixels will be small. This phenomenon is used to set the range of edge pixels for quality determination. The range of edge pixels to be set is arbitrary. If the value of the edge pixels is small, the possibility of defective products being mixed in with those judged as good increases. Conversely, if the value of the edge pixels is large, the possibility of good products being mixed in with those judged as defective increases. Therefore, it is preferable to collect data on the edge pixels of good products and the edge pixels of defective products and set the edge pixels for quality determination. The edge pixels will be small when the amount of powder attached is small relative to the target value. Conversely, the edge pixels will be large when the amount of powder attached is large relative to the target value. Furthermore, when the target value is set to 100, an example of the range of edge pixels for quality determination is 100 ± 60. This indicates that products with edge pixels within the range of 100±60 are judged as good. The plus / minus range can be arbitrarily changed. Furthermore, using machine learning is also an effective method when determining whether a product is good or bad.

[0034] In the adhesion process P1, the base powder 6 may be applied while the ceramic molded body 1 is stationary, or the base powder 6 may be applied while the ceramic molded body 1 is moving. More specifically, the base powder 6 is applied by spraying while the ceramic molded body 1 is moving. By applying the base powder 6 while the ceramic molded body 1 is moving, mass production efficiency can be improved.

[0035] As mentioned above, there are various methods for forming the ceramic molded body 1, such as the doctor blade method and the mold molding method. The doctor blade method allows for the production of wide, long, sheet-like molded bodies. The powder 6 is applied to the long, sheet-like molded body using a spray method. The long, sheet-like molded body with the powder 6 applied is then rolled up and used in the next process. By applying the powder 6 while moving the ceramic molded body 1, the processes of sheet molding, application of the powder 6, inspection of the amount of powder 6 applied, and rolling up the molded body can be performed continuously.

[0036] In mold molding, a sheet-like molded body is produced using a mold. Mold molding allows for the creation of a sheet-like molded body that matches the size of the mold. Toko By attaching the bedding powder 6 while transporting it using a conveyor belt or similar device, mass production efficiency can be improved.

[0037] In inspection step P2, the amount of adhesion may be inspected with the ceramic molded body 1 stationary, or the amount of adhesion may be inspected while the ceramic molded body 1 is moving. Mass production efficiency can be further improved by performing inspection step P2 while the ceramic molded body 1 is moving. Furthermore, by using a photoelectric sensor or an image sensor, the amount of adhesion of the base powder 6 can be inspected even while the ceramic molded body 1 is moving.

[0038] The above-described method for inspecting the amount of substrate powder allows for efficient inspection of the amount of substrate powder 6. Furthermore, since the inspection can be performed while moving the ceramic molded body 1, mass production efficiency can be improved. The substrate powder inspection method according to this embodiment can be used in a method for manufacturing ceramic sintered bodies.

[0039] Figure 5 is a flowchart showing a method for manufacturing a ceramic substrate according to the embodiment. As shown in Figure 5, the method for manufacturing a ceramic substrate according to the embodiment M2 comprises a step of performing an inspection method M1 (adhesion step P1 and inspection step P2), a post-processing step P3, and a sintering step P4. The inspection method M1 determines whether the amount of adhesive powder 6 is within a predetermined range. If it is determined that the amount of adhesive powder 6 is greater than the predetermined range, or if it is determined that the amount of adhesive powder 6 is less than the predetermined range, the post-processing step P3 is performed. If it is determined that the amount of adhesive powder 6 is within the predetermined range, the post-processing step P3 can be omitted.

[0040] For example, if the inspection method for the amount of adhesive powder determines that there is a large amount of adhesive powder, a step to reduce the amount of adhesive powder 6 may be performed as a post-processing step P3. By reducing the amount of adhesive powder 6 that has adhered excessively, defective products can be converted into good products. This can improve the yield of ceramic sintered bodies. Methods such as using air blowing can be used to reduce the amount of adhesive powder 6. With air blowing, excess adhesive powder 6 is blown off by blowing air onto the surface 2 of the ceramic molded body 1, thereby reducing the amount of adhesive powder 6. After performing the step to reduce the amount of adhesive powder 6, the inspection method for the amount of adhesive powder according to the embodiment may be performed as necessary.

[0041] If the inspection method for the amount of adhesive powder determines that there is a large amount of adhesive powder, a step of removing the ceramic molded body 1 to which a large amount of adhesive powder 6 is attached may be performed as a post-treatment step P3. In this removal step, if a long sheet-like molded body is produced, only the areas to which the adhesive powder 6 is attached should be removed. If multiple sheet-like molded bodies are produced, only the molded bodies to which the adhesive powder 6 is attached should be removed.

[0042] If the inspection method for the amount of adhesive powder determines that the amount of adhesive powder is insufficient, a step of reapplying the adhesive powder 6 may be performed as a post-processing step P3. By reapplying the adhesive powder 6, defective products can be converted into good products. This improves the yield of the ceramic sintered body. Furthermore, after reapplying the adhesive powder 6, the inspection method for the amount of adhesive powder according to the embodiment may be performed as necessary.

[0043] If the inspection method for the amount of adhesive powder determines that the amount of adhesive powder is small, a step of removing the ceramic molded body 1 with a small amount of adhesive powder 6 attached may be performed as a post-treatment step P3. For this removal step, if a long sheet-like molded body is produced, only the areas with a small amount of adhesive powder 6 attached should be removed. If multiple sheet-like molded bodies are produced, only the molded bodies with a small amount of adhesive powder 6 attached should be removed.

[0044] In the sintering process P4, the ceramic molded body 1, with the amount of powder adhering to it controlled within a predetermined range, is sintered to obtain a ceramic sintered body. When powder 6 is attached to a long sheet-like molded body, the ceramic sintered body is cut to the required size. The sintering temperature in the sintering process P4 is preferably in the range of 1600°C to 2000°C. The pressure in the space where the sintering process P4 is performed may be pressurized, atmospheric pressure, or reduced pressure. Various atmospheres such as air, an inert atmosphere, or a vacuum can be applied to the sintering process P4.

[0045] Figure 6 shows an example of a method for manufacturing a ceramic substrate according to an embodiment. In Figure 6, reference numeral 9 denotes a base plate. In the sintering process P4, as shown in Figure 6, a ceramic molded body 1 having a base powder adhesion layer 3 is placed on a base plate 9. A boron nitride plate or the like is used for the base plate 9. Multiple ceramic molded bodies 1 having a base powder adhesion layer 3 are stacked and arranged. If necessary, another base plate 9 may be placed on top of the stacked multiple ceramic molded bodies 1. Furthermore, multiple other ceramic molded bodies 1 having a base powder adhesion layer 3 may be stacked and arranged on top of the base plate 9.

[0046] Because the amount of powder adhering to the surface 2 of the ceramic molded body 1 is controlled, the occurrence of defective products can be suppressed even when the sintering process is performed with multiple ceramic molded bodies 1, each having a powder-adhering layer 3, stacked and arranged in a stacked manner. For example, it is possible to prevent stacked ceramic sintered bodies from bonding together.

[0047] Furthermore, stacked ceramic sintered bodies can be separated with minimal stress. Minimal stress refers to, for example, human force or the force of air blowing. If large stress is required to separate stacked ceramic sintered bodies, there is a possibility that the ceramic sintered bodies will break during the separation process. From this standpoint, the embodiment can improve yield.

[0048] Furthermore, surface irregularities of the ceramic sintered body can be suppressed. The ceramic sintered body is preferably a ceramic substrate. Even if the thickness of the ceramic substrate is 3 mm or less, surface irregularities can be suppressed by controlling the amount of powder adhering to it within a predetermined range. Moreover, surface irregularities can be suppressed even if the thickness of the ceramic substrate is 1 mm or less. In other words, the inspection method according to this embodiment is suitable for manufacturing ceramic substrates.

[0049] The ceramic substrate is preferably a silicon nitride substrate. Examples of ceramic substrates include silicon nitride substrates, aluminum nitride substrates, aluminum oxide substrates, zirconium oxide substrates, and silicon carbide substrates. Among these, silicon nitride substrates are expensive, and therefore offer a significant improvement in yield.

[0050] (Examples) (Examples 1-8, Comparative Examples 1-2) In Examples 1 to 6, silicon nitride molded bodies were prepared as ceramic molded bodies. Long sheet-like molded bodies were fabricated from the silicon nitride molded bodies using the doctor blade method. The width of the long sheet-like molded body was 1 m. The thickness of the sheet-like molded body was set so that a silicon nitride substrate with a thickness of 0.32 mm could be obtained as a sintered body.

[0051] In Example 7, an aluminum nitride molded body was prepared as the ceramic molded body. A long sheet-like molded body was fabricated from the aluminum nitride molded body using the doctor blade method. The width of the long sheet-like molded body was 1 m. The thickness of the sheet-like molded body was set so that an aluminum nitride substrate with a thickness of 0.635 mm was obtained as a sintered body.

[0052] In Example 8, an aluminum oxide molded body was prepared as the ceramic molded body. A long sheet-like molded body was fabricated from the aluminum oxide molded body using the doctor blade method. The width of the long sheet-like molded body was 1 m. The thickness of the sheet-like molded body was set so that an aluminum oxide substrate with a thickness of 0.635 mm was obtained as a sintered body.

[0053] In the examples and comparative examples, a coating step was performed in which a base powder was applied to the surface of a long sheet-like molded body. Boron nitride (BN) powder was used as the base powder. The base powder was applied to the ceramic molded body by a spray method. An inspection step was performed on the ceramic molded body to which the base powder had been applied. The conditions for manufacturing the molded body, the conditions for applying the base powder, and the conditions for the inspection step are shown in Table 1.

[0054] [Table 1]

[0055] In Table 1, under "Presence or Absence of Movement," "Yes" indicates that the sheet-like molded body was moved while the powder was applied to it. "No" indicates that the sheet-like molded body was stationary while the powder was applied to it. "Presence or Absence of Edge Detection" indicates whether or not edge detection was performed on the obtained image. The "Range of Edge Pixels Considered Good" was set based on data with a yield of 98% or higher. In the example, areas that fell below the edge pixel limit for good products were removed. In other words, only those judged to be good products according to the powder application amount inspection method of the embodiment were subjected to the sintering process.

[0056] A sheet-like molded body with a powder coating attached was cut to 200 mm x 150 mm. The cut molded bodies were stacked and subjected to a sintering process. The sintering process was carried out within the range of 1700 to 1900°C. A ceramic substrate was produced by this sintering process. In both the example and comparative example, 1000 ceramic substrates were produced, and the yield and surface flatness were examined.

[0057] For yield, ceramic substrates that could be peeled off by air blowing or by human force were considered good products. Ceramic substrates that could not be peeled off by air blowing or by human force, or that were damaged during peeling, were considered defective products. The yield (%) is the percentage of good products out of 1000 pieces. Examples with a yield of 99% to 100% were classified as "excellent," examples with a yield of 95% to less than 99% were classified as "good," and examples with a yield of less than 95% were classified as "poor."

[0058] For surface flatness, ceramic substrates with a difference of 50 μm or less between the maximum value of the convex and concave areas on the surface were considered good. The difference between the maximum value of the convex and concave areas was calculated by image analysis of the surface of the ceramic substrate. Examples where the percentage of ceramic substrates with a difference of 50 μm or less was between 98% and 100% were classified as "excellent," examples where it was between 95% and less than 98% were classified as "good," and examples where it was less than 95% were classified as "poor." The results are shown in Table 2.

[0059] [Table 2]

[0060] As can be seen from Table 2, the ceramic sintered body manufacturing method according to the examples showed improved yield and surface flatness. Example 2, which met the preferred conditions, yielded the best results. Therefore, it can be seen that the inspection method functions effectively even when the powder is applied while the sheet-like molded body is moved. On the other hand, in Comparative Examples 1 and 2, the inspection method according to the embodiment was not applied, resulting in lower yield and flatness compared to the examples. This is because uneven application of the powder was not detected. In particular, as in Comparative Example 2, uneven application of the powder was more likely to occur when the powder was applied while the sheet-like molded body was moved. As molded bodies with uneven application were sintered, the yield and flatness decreased.

[0061] Next, molded bodies that were determined to be defective according to the inspection method for the amount of adhesive powder according to Examples 1 to 8 were subjected to a process to make them good products. In areas where the amount of adhesive powder was determined to be high, some of the adhesive powder was removed by air blowing. In areas where the amount of adhesive powder was determined to be low, adhesive powder was reapplied. After that, the sintering process was carried out in the same manner as in Examples 1 to 8. The yield and surface flatness of the obtained ceramic substrates were examined. The measurement conditions were the same as in Examples 1 to 8. The results are shown in Table 3.

[0062] [Table 3]

[0063] In Table 3, in Example 1B, the amount of powder adhering to the molded body that was judged as defective in Example 1 was controlled to an amount that would result in a good product. Similarly, in Examples 2B to 8B, the amount of powder adhering to the molded body that was judged as defective in Examples 2 to 8 was controlled to an amount that would result in a good product.

[0064] As can be seen from Table 3, by readjusting the amount of powder adhering to the appropriate level, defective products could be converted into good products. By using the discrimination method based on the powder adhering amount inspection method according to the embodiment, it is possible to perform a process to improve only the molded products that have been determined to be defective into good products. This improves productivity. In addition, since the amount of molded products that are discarded can be reduced, environmental performance can also be improved.

[0065] Embodiments of the present invention include the following features. (Feature 1) The process involves applying a coating powder to the surface of a ceramic molded body, An inspection step in which the amount of the bedding powder attached is inspected by detecting the reflected or transmitted light on the surface using a photoelectric sensor or an image sensor, A method for inspecting the amount of bedding powder attached, equipped with the following features. (Feature 2) The aforementioned image sensor is an infrared image sensor or an ultraviolet image sensor. The method for inspecting the amount of bedding powder adhering to the surface according to feature 1, wherein reflected light from the surface is detected using the infrared image sensor or the ultraviolet image sensor. (Feature 3) A method for inspecting the amount of bedding powder attached, according to feature 1 or feature 2, wherein, in the inspection step, edge detection is performed on an image obtained by detecting the reflected light or the transmitted light. (Feature 4) The method for inspecting the amount of bedding powder adhering to the surface, according to any one of features 1 to 3, wherein the average particle size of the bedding powder is 20 μm or less. (Feature 5) The method for inspecting the amount of powder adhering to the surface, according to any one of features 1 to 4, wherein the ceramic molded body is a silicon nitride molded body. (Feature 6) The method for inspecting the amount of adhesive powder according to any one of features 1 to 5, wherein the adhesive powder is boron nitride powder. (Feature 7) A method for inspecting the amount of adhesive powder according to any one of features 1 to 6, wherein, in the adhesion step, the adhesive powder is applied to the surface of the ceramic molded body by a spray method while the body is being moved. (Feature 8) A step of performing the inspection method for the amount of bedding powder attached, as described in any one of Feature 1 to Feature 7, A sintering step in which the ceramic molded body determined to be a good product by the inspection method is sintered, A method for manufacturing a ceramic substrate equipped with [a specific feature / feature]. (Feature 9) A method for manufacturing a ceramic substrate according to feature 8, comprising a step of reducing the amount of adhesion when it is determined that the amount of adhesion is large. (Feature 10) A method for manufacturing a ceramic substrate according to feature 8, further comprising a step of removing the ceramic molded body to which a large amount of the dusting powder is attached when it is determined that the amount of dusting powder is large. (Feature 11) A method for manufacturing a ceramic substrate according to feature 8, further comprising a step of reapplying the base powder if it is determined that the amount of adhesion is insufficient. (Feature 12) A method for manufacturing a ceramic substrate according to feature 8, further comprising a step of removing the ceramic molded body to which the amount of adhesive is attached if it is determined that the amount of adhesive is small.

[0066] Although several embodiments of the present invention have been illustrated above, these embodiments are presented as examples only and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims of the invention and its equivalents. Furthermore, the embodiments described above can be implemented in combination with each other. [Explanation of Symbols]

[0067] 1…Ceramic molded body 2...Surface part 3…Bedding powder adhesion layer 4…Sensor 5…Spray 6...Small powder 7…Lighting equipment 8...Sensor 9…Singing board

Claims

1. The process involves applying a coating powder to the surface of a ceramic molded body, An inspection step in which the amount of the bedding powder attached is inspected by detecting the reflected or transmitted light on the surface using a photoelectric sensor or an image sensor, Equipped with, A method for inspecting the amount of dust adhering to a bed base, comprising detecting the reflected light or the transmitted light in the inspection step and performing edge detection on the image obtained.

2. The aforementioned image sensor is an infrared image sensor or an ultraviolet image sensor. The method for inspecting the amount of bedding powder adhering to the surface according to claim 1, wherein reflected light from the surface is detected using the infrared image sensor or the ultraviolet image sensor.

3. The method for inspecting the amount of bedding powder adhering to the surface, according to claim 1 or claim 2, wherein the average particle size of the bedding powder is 20 μm or less.

4. The method for inspecting the amount of powder adhering to a bed of material according to claim 1 or claim 2, wherein the ceramic molded body is a silicon nitride molded body.

5. The method for inspecting the amount of bedding powder adhering to a surface, according to claim 1 or claim 2, wherein the bedding powder is boron nitride powder.

6. The method for inspecting the amount of bedding powder adhering to a surface, according to claim 4, wherein the bedding powder is boron nitride powder.

7. A method for inspecting the amount of powder attached to a surface, according to claim 1 or 2, wherein in the attachment step, the powder is attached to the surface of the ceramic molded body by a spray method while the body is being moved.

8. The method for inspecting the amount of adhesive powder attached to the surface of the ceramic molded body by spraying while moving the ceramic molded body during the adhesion step, as described in claim 5.

9. A method for inspecting the amount of bedding powder adhesion according to claim 1 or claim 2, wherein the amount of bedding powder adhesion is determined to be good when the edge pixels of the bedding powder are within the range of 100 ± 60.

10. The method for inspecting the amount of bedding powder adhesion according to claim 6, wherein the amount of bedding powder adhesion is determined to be good when the edge pixels of the bedding powder are within the range of 100 ± 60.

11. A step of performing the method for inspecting the amount of bedding powder adhering to the surface described in claim 1 or claim 2, A sintering step in which the ceramic molded body determined to be a good product by the inspection method is sintered, A method for manufacturing a ceramic substrate equipped with [a specific feature / feature].

12. A method for manufacturing a ceramic substrate according to claim 11, further comprising a step of reducing the amount of adhesion when it is determined that the amount of adhesion is large.

13. A method for manufacturing a ceramic substrate according to claim 11, further comprising the step of removing the ceramic molded body to which a large amount of the dusting powder is attached when it is determined that the amount of dusting powder is large.

14. A method for manufacturing a ceramic substrate according to claim 11, further comprising the step of reapplying the base powder if it is determined that the amount of adhesion is insufficient.

15. A method for manufacturing a ceramic substrate according to claim 11, further comprising the step of removing the ceramic molded body to which the amount of adhesive is attached if it is determined that the amount of adhesive is small.

Images