Sintered compact containing in, ga, zn and o, and method for producing same

Abstract

The present disclosure addresses the problem of providing: a sintered compact having high purity and high relative density, and containing In, Ga, Zn and O; and a method for producing the same.　As a sintered compact containing indium (In), gallium (Ga), zinc (Zn), and oxygen (O), the sintered compact has a total content of Li, Na, Al, Si, K, Cr, Fe, Cu, Sn, Pb, and Zr of less than 10 wtppm, a Zr content of less than 1 wtppm, and a relative density of at least 95%.

Description

Sintered body containing In, Ga, Zn, and O and method for producing the same

[0001] The present disclosure relates to a sintered body containing In, Ga, Zn, and O and a method for producing the same.

[0002] An oxide material composed of indium (In), gallium (Ga), zinc (Zn), and oxygen (O) is called IGZO (an abbreviation derived from the initials of each component element), and is widely used as a transparent conductive film due to its high conductivity and high transmittance in the visible light region. For example, IGZO films are used as transparent electrodes in plasma displays, liquid crystal displays, organic EL displays, touch panels, solar cells, and the like. In recent years, attempts have been made to use IGZO as a semiconductor device (such as a TFT) that takes advantage of its semiconductor properties.

[0003] IGZO films are typically formed using a sputtering target made by processing a sintered body containing In, Ga, Zn, and O. Sputtering is a type of physical vapor deposition (PVD) technique in which argon ions are bombarded at high speed onto a sputtering target placed opposite a substrate, causing atoms ejected from the sputtering target to deposit on the substrate, forming a film. Typically, a film with the same composition as the sputtering target is formed.

[0004] The following prior art is known regarding sputtering targets containing In, Ga, Zn, and O. For example, Patent Document 1 discloses a sintered body having a relative density of 95% or more and an average crystal grain size of 10 μm or less. Patent Document 2 discloses a sintered body containing zirconium in a weight ratio of 20 ppm or more but less than 100 ppm, having a relative density of 95% or more, and a flexural strength of 100 MPa or more.

[0005] Patent Document 3 describes InGaZnO ４Patent Document 4 discloses a sputtering target containing less than 20 ppm by mass of zirconium and having a relative density of 95% or more. Patent Document 5 discloses a sintered body having an impurity metal element M (Sn, Zr, Ti, Mo, Si, Cr, W, Ge, V, Mn) of less than 10 ppm and a relative density of 100%.

[0006] JP 2007-223849 A JP 2014-024738 A JP 2015-024944 A JP 2023-67117 A JP 2014-224036 A

[0007] If impurities are contained in a sintered body containing In, Ga, Zn, and O, the sputtering target produced by processing the sintered body will cause an increase in particles during sputtering. Furthermore, if impurities are present in the IGZO film after film formation, problems such as a decrease in transmittance and a decrease in mobility as a TFT element will occur. On the other hand, sputtering targets are produced by sintering raw material powders, and in this process, the impurities contained in the raw material powder act as sintering aids to obtain a high-density sintered body. Therefore, if the impurities contained in the sintered body are drastically reduced, it becomes difficult to produce a high-density sintered body.

[0008] In view of the above problems, an object of the present disclosure is to provide a sintered body containing In, Ga, Zn, and O, which has high purity and a high relative density, and a method for producing the same.

[0009] As a result of intensive research to solve the above-mentioned problems, the present inventors have found that by devising a sintering method, a sintered body with a high relative density can be obtained even when high-purity raw material powder is sintered. That is, the gist of the present disclosure is as follows. [1] A sintered body containing indium (In), gallium (Ga), zinc (Zn), and oxygen (O), wherein the total content of Li, Na, Al, Si, K, Cr, Fe, Cu, Sn, Pb, and Zr is less than 10 wtppm, the Zr content is less than 1 wtppm, and the relative density is 95% or more. [2] The sintered body according to [1], which has an average crystal grain size of 5 μm or less. [3] The sintered body according to [1], which has a volume resistivity of 100 mΩ·cm or less. [4] The sintered body according to any one of [1] to [3], which has a circular plate shape, a rectangular plate shape, or a cylindrical shape. [5] A method for producing a sintered body according to any one of [1] to [4], comprising: ２ O ３ Powder, Ga ２ O ３ A method for producing a sintered body, comprising the steps of: mixing raw material powders of ZnO powder and ZnO powder without pulverizing them; pressure-sintering the resulting mixed powder under vacuum or an inert gas atmosphere; and using metal members during the pressure-sintering to prevent a reduction reaction between the sintering raw materials and the sintering equipment members.

[0010] According to the present disclosure, it is possible to provide a sintered body containing In, Ga, Zn, and O, which has high purity and a high relative density, and a method for producing the same.

[0011] Below, the present disclosure will be described with reference to specific embodiments, but each configuration and combination thereof in each embodiment is merely an example, and addition, omission, substitution, and other modifications of configurations are possible as appropriate within the scope that does not deviate from the gist of the present disclosure.

[0012] Sintered bodies containing indium (In), gallium (Ga), zinc (Zn), and oxygen (O) contain impurities derived from the oxide raw material powder and zirconium derived from the milling process (because zirconia beads are used as the milling media), which inhibit the high purity of sputtering targets produced by machining the sintered bodies. Existing sputtering targets containing indium (In), gallium (Ga), zinc (Zn), and oxygen (O) actually have a purity equivalent to 3N5 (total impurity content of 500 wtppm).

[0013] Patent Document 3 describes the use of raw material powder with a purity of 99.99% or higher, but discloses the use of zirconia beads in the milling and mixing steps, which inevitably results in the inclusion of zirconium as an impurity. In particular, in the case of atmospheric sintering (air or oxygen atmosphere), the raw material powder needs to be milled to reduce the particle size in order to increase the density of the sintered body, and this tends to increase the inclusion of zirconium.

[0014] Furthermore, Patent Document 4 discloses that by controlling the grinding conditions, a sintered body with a high relative density can be obtained while reducing the zirconium content to 20 ppm by mass or less. On the other hand, it discloses that a total of 10 ppm by mass or more of unavoidable impurities is contained. In Patent Document 4, the sintered body is produced by atmospheric sintering, and it is assumed that the unavoidable impurities act as sintering aids, resulting in a high-density sintered body.

[0015] Furthermore, Patent Document 5 discloses that powder with a purity of 4N or more is used as a raw material. However, in the mixing process, hard ZrO ２It is disclosed that balls are used to mix the powder in a wet ball mill for 18 hours, but in this case, it is inevitable that zirconium will be mixed in as an impurity. Although it is unclear whether this is the reason, Zr is excluded from the impurity metal elements in Patent Document 5. Conventionally, IGZO sintered bodies have had a high Zr content, so reducing impurities, including Zr, can contribute to reducing particles when forming a sputtering target. On the other hand, because Zr contributes as a sintering aid, reducing Zr can make it difficult to obtain a high-density sintered body by atmospheric sintering.

[0016] As described above, impurities (metal elements other than In, Ga, and Zn) contained in the sintered body contribute to improving the relative density of the sputtering target as sintering aids, but they can also cause an increase in particles during sputtering and can also cause the properties of the deposited film to deteriorate. Therefore, it can be said that impurities in the sputtering target are in a trade-off relationship between improving the relative density and reducing particles.

[0017] <1. Sintered Body> A sintered body according to one embodiment of the present disclosure contains indium (In), gallium (Ga), zinc (Zn), and oxygen (O). In the sintered body according to this embodiment, the content ratio of In, Ga, and Zn is not particularly limited, but can be within the following ranges in terms of the atomic ratio of In, Ga, and Zn: 0.05≦In / (In+Ga+Zn)≦0.90 0.05≦Ga / (In+Ga+Zn)≦0.90 0.05≦Zn / (In+Ga+Zn)≦0.90 Component analysis of the sintered body according to the present disclosure is performed by inductively coupled plasma optical emission spectroscopy (ICP-OES).

[0018] <2. Impurities> The sintered body according to this embodiment has a total content of the impurity elements Li, Na, Al, Si, K, Cr, Fe, Cu, Sn, Pb, and Zr of less than 10 wtppm, and a Zr content of less than 1 tppm. The above impurity elements are derived from the raw material powder or the pulverization process. These impurity elements, particularly Zr, are preferably reduced as much as possible because they may cause an increase in particles due to arcing during sputtering, a decrease in the transmittance of the IGZO film, and a decrease in the mobility of TFT elements. The content of each impurity element is measured by glow discharge mass spectrometry (GDMS). The total content of the impurity elements is more preferably 8 wtppm or less, and the Zr content is preferably less than 0.5 wtppm. If the content of an impurity element is below the detection limit, the detection limit value is used for calculation. For example, when the detection limit of Cu is 0.1 wtppm, the Cu content is set to 0.1 wtppm to calculate the total content of impurity elements.

[0019] <3. Relative Density> The sintered body according to this embodiment has a relative density of 95% or more. The relative density of the sintered body is desirable because it affects the generation of particles due to arcing and nodules during sputtering in the sputtering target processed from the sintered body. Furthermore, a high-density sputtering target can suppress the occurrence of cracks and fractures. Because impurities function as sintering aids, reducing the impurities makes it difficult to increase the density of the sintered body. However, this disclosure is particularly excellent in that it achieves high purity and high density using the sintering method described below. The relative density is preferably 97% or more, more preferably 98% or more, and even more preferably 99% or more.

[0020] "Relative density" is expressed as relative density (%) = measured density / true density × 100. The measured density is a value obtained by dividing weight by volume, and is calculated by determining the volume of a sample (a small piece of sintered body) using the Archimedes method. The true density is calculated by analyzing the components of the sintered body and converting the atomic ratios (at%) of In, Ga, and Zn to the total of 100 at% of the constituent elements In, Ga, and Zn into oxide mass ratios (mass%), as follows: ２ O３ , Ga ２ O ３ , and the theoretical density of ZnO is calculated from the following formula: True density (g / cm ３ )=(W1+W2+W3) / (W1 / d1+W2 / d2+W3 / d3) W1:In ２ O ３ Mass ratio (mass%) of W2:Ga ２ O ３ W3: Mass ratio of ZnO (mass%) Theoretical density: d1: In ２ O ３ Theoretical density (7.18 g / cm ３ ) d2: Ga ２ O ３ Theoretical density (5.95 g / cm ３ ) d3: Theoretical density of ZnO (5.61 g / cm ３ )

[0021] <4. Volume Resistivity> The sintered body according to this embodiment preferably has a volume resistivity of 100 mΩ·cm or less. A low volume resistivity of the sintered body enables DC (direct current) sputtering in a sputtering target made from the sintered body. Furthermore, the lower the volume resistivity, the more stable the DC (direct current) sputtering, and particle reduction can be expected. The volume resistivity is more preferably 50 mΩ·cm or less, even more preferably 10 mΩ·cm or less, and particularly preferably 1 mΩ·cm or less. The volume resistivity is measured three times at the same location on a cross section (a cross section parallel to the sputtering surface) near the center of the sintered body (near the center of the circle in the case of a circle, near the intersection of the diagonals in the case of a rectangle, or near the same distance from the upper and lower bases of the side surface in the case of a cylindrical shape) using a DC four-probe method, and the sum of the measurement results is divided by the number of measurements to obtain an average value.

[0022] 5. Average Crystal Grain Size The sintered body according to this embodiment preferably has an average crystal grain size of 10 μm or less. When the crystalline structure of a sputtering target obtained by processing a sintered body is fine, the mechanical strength is increased and the occurrence of cracks and fractures can be suppressed. More preferably, it is 5 μm or less, and even more preferably, it is 3 μm or less. The average crystal grain size is measured using the cord method. The cord method involves drawing lines of any length from grain boundary to grain boundary, counting the number of intersections with the grain boundaries, and dividing the length of the lines by the number of intersections to determine the average crystal grain size. A sample for observation is cut out from the sintered body, and the surface of the cut sample is mirror-polished. A micrograph of the mirror-polished sample surface is taken from six fields of view at 5,000x magnification using a scanning electron microscope. Three lines (in the direction of the long side of the image) are drawn on the captured image, and the arithmetic mean of the lengths at which each line intersects with the crystal grains is measured to determine the crystal grain size. The arithmetic mean of the six fields of view is the average crystal grain size. However, if the number of particles crossed by each line in the field of view is less than 10, it is necessary to use a magnification of 2000x or 1000x as appropriate.

[0023] A method for manufacturing a sintered body according to an embodiment of the present disclosure will be described. However, the manufacturing conditions and the like below are not limited to the disclosed range, and it is clear that some omissions and modifications may be made. In addition, detailed descriptions of well-known manufacturing steps and processing operations will be omitted to avoid unnecessarily obscuring the disclosed manufacturing method.

[0024] (1. Raw material powder) In ２ O ３ Powder (nominal purity: 4N or higher), Ga ２ O ３ Powder (nominal purity: 5N or higher) and ZnO powder (nominal purity: 5N or higher) are prepared, and these raw material powders are weighed out so as to achieve the desired atomic ratio of In, Ga, and Zn. It is preferable to use raw material powders with a small particle size, and powders with a median diameter (D50) of 0.1 μm to 10 μm can be used.

[0025] (2. Mixing Step) The weighed raw material powders are mixed. As a mixing method, dry mixing or wet mixing can be used. For example, a dispersant can be added to pure water, and then each raw material powder is added and stirred to mix. Conventionally, the raw material powders are mixed and pulverized, and then granulated. However, during pulverization, impurities can be mixed from the pulverization media or pulverization device components and remain in the sputtering target obtained by processing the sintered body. Therefore, in order to suppress the mixing of impurities, it is preferable to perform mild pulverization or not perform pulverization at all.

[0026] (3. Sintering Process) Conventionally, raw material powder slurry is granulated, then press-molded, and the resulting molded body is sintered (so-called atmospheric sintering) at about 1,350°C in an air or oxygen atmosphere. However, if the pulverization and granulation processes are omitted (or mildly pulverized) to avoid the inclusion of impurities, poor sintering occurs due to the coarseness of the raw material powder, and the relative density increases to only about 85%, making it impossible to produce a dense sintered body. Therefore, in order to improve the relative density by atmospheric sintering, the pulverization process is essential.

[0027] On the other hand, in the present disclosure, pressure sintering such as hot pressing (uniaxial pressure sintering) or HIP (hot isostatic pressing) is used instead of atmospheric pressure sintering. By using pressure sintering, it is possible to obtain a sintered body with a relatively high relative density without making the particle size sufficiently small. However, in pressure sintering under a vacuum or inert gas atmosphere, carbon (C), which is a sintering device component, is mixed with the target raw material (In ２ O ３ , Ga ２ O ３ , ZnO mixed powder), especially In ２ O ３ It is not possible to achieve high density by reducing In during hot pressing. ２ O ３ The reduction of In occurs from the outer periphery in contact with the carbon member. ２ O ３ When the weight loss ([weight of mixed powder before sintering] - [weight of sintered body]) / [mixed powder before sintering] x 100), which is an index of reduction, exceeds 5% (in this case, In ２ O ３(It is determined that reduction has occurred), and the reduced layer gradually thickens. If the weight loss exceeds 10%, the reduced layer becomes too thick, making it difficult to measure the density of the sintered body. Therefore, it is preferable that the weight loss be within 5%. Therefore, the present disclosure provides a method for preventing a reduction reaction during sintering by installing a metal member between the sintering device member and the target raw material, thereby obtaining a high-density sintered body.

[0028] (3-1. Sintering Conditions) Pressure sintering is carried out in a vacuum atmosphere or an inert atmosphere. It is preferable that the holding temperature during sintering is 1150°C or higher, and the holding time is 1 hour or more and 20 hours or less. If the holding temperature is too low, the relative density of the sintered body will not increase, while if the holding temperature is too high, the crystal grains may become coarse. Furthermore, if the holding time is too short, the relative density of the sintered body will not increase sufficiently, and if the holding time is too long, cracks may occur inside the sintered body. There are various methods for pressure sintering, but it is preferable to use hot pressing, which is primary axial pressure sintering, and HIP or the like may be performed after hot pressing.

[0029] (3-2. Metallic member) Sintering raw material (In ２ O ３ , Ga ２ O ３ In order to prevent a reduction reaction between the sintering material (a mixed powder of ZnO and ZnO) and the sintering device material (carbon), a metal member is placed where they come into contact. Since the metal member itself may reduce the sintering material depending on the type of metal member, it is necessary to use a metal material that forms a metal oxide with a higher standard Gibbs energy of formation than the sintering material. For example, Mo, Ni, Co, etc. can be used as the metal member. Furthermore, while foil-shaped metal members are preferred due to the structure of the device, their shape and size are not particularly limited. By using such metal members and adopting a pressure sintering process that suppresses reduction, milling of the raw material powder is unnecessary, making it possible to reduce impurities resulting from the milling process.

[0030] (4. Finishing) The sintered body obtained through the above sintering step can be processed into a desired shape using a processing machine such as a surface grinder, a cylindrical grinder, a lathe, a cutting machine, or a machining device, as needed. There are no particular restrictions on the shape of the sputtering target, and it can be a circular plate, a rectangular plate, a cylindrical shape, or the like. If necessary, the sputtering target can be bonded to a backing plate made of oxygen-free copper, titanium, or the like. There are no particular restrictions on the thickness of the sputtering target, but it can usually be 4 mm or more and 15 mm or less.

[0031] The following description will be given based on examples and comparative examples. Note that these examples are merely examples and are not intended to limit the scope of the present invention. That is, the present invention is limited only by the scope of the claims and includes various modifications other than the examples included in this disclosure. Note that, since sputtering targets are produced by machining a sintered body, the physical properties of the sputtering target are, in principle, equivalent to those of the sintered body.

[0032] (Example 1) In having an average particle size (D50) of 2 μm or less ２ O ３ Ga powder (nominal purity: 4N), average particle size (D50) of 1 μm or less ２ O ３ In powder (nominal purity: 5N) and ZnO powder (nominal purity: 5N) with an average particle size (D50) of 1 μm or less were prepared, and were weighed and mixed to obtain an In:Ga:Zn ratio of 1:1:1. Next, this mixed powder was filled into a carbon die covered with molybdenum (Mo) metal foil, and then sintered in an argon atmosphere at a temperature of 1250°C and a pressure of 250 kgf / cm. ２Hot press sintering was performed under the conditions of 0.1% SiO2, 0.1% SiO2, and 0.2% SiO2 holding time of 1 hour to produce a disk-shaped sintered body with a diameter of 180 mm. The impurity content, relative density, volume resistivity, and average crystal grain size of the obtained sintered body were determined according to the methods described above. The results are shown in Table 1. As shown in Table 1, the total impurity content was 6.97 wtppm, and the relative density was 100.3%, resulting in a sintered body with high purity and high relative density. The sintered body also had the desired volume resistivity of 0.55 mΩ·cm and average crystal grain size of 1.9 μm.

[0033]

[0034] (Comparative Example 1) In having an average particle size (D50) of 2 μm or less ２ O ３ Ga powder (nominal purity: 4N), average particle size (D50) of 5 μm or less ２ O ３ Powder (nominal purity: 4N) and ZnO powder (nominal purity: 3N) with an average particle size (D50) of 1 μm or less were prepared and weighed to give an In:Ga:Zn = 1:1:1 (atomic ratio). Next, these powders were finely pulverized in a wet bead mill (pulverization media: zirconia beads), and then dispersed in pure water to prepare a slurry. This was then dried and granulated in a spray dryer to obtain a mixed powder. The obtained mixed powder was subjected to a surface pressure of 400 kgf / cm. ２ The mixture was uniaxially pressed at 1360°C to produce a disk-shaped compact with a diameter of 280 mm. Then, atmospheric sintering was carried out in an oxygen atmosphere at a sintering temperature of 1360°C for a holding time of 20 hours to produce a sintered body. The impurity content, relative density, volume resistivity, and average crystal grain size of the obtained sintered body were determined according to the methods described above. The results are shown in Table 1. As shown in Table 1, the impurity content was 121.58 wtppm.

[0035] (Comparative Example 2) In having an average particle size (D50) of 2 μm or less ２ O ３ Ga powder (nominal purity: 4N), average particle size (D50) of 5 μm or less ２ O ３ In powder (nominal purity: 4N) and ZnO powder (nominal purity: 3N) with an average particle diameter (D50) of 1 μm or less were prepared and weighed so that the atomic ratio of In:Ga:Zn was 1:1:1.２ O ３ The powder was pulverized using a steam jet mill (dry pulverization), and then the pulverized Ga ２ O ３ Powder, In ２ O ３ The powder and ZnO powder were finely pulverized in a wet bead mill (pulverization media: zirconia beads), then dispersed in pure water to prepare a slurry, which was then dried and granulated in a spray dryer to obtain a mixed powder. The obtained mixed powder was subjected to a surface pressure of 400 kgf / cm. ２ The mixture was uniaxially pressed at 1360°C to produce a disk-shaped compact with a diameter of 280 mm. Then, atmospheric sintering was carried out in an oxygen atmosphere at a sintering temperature of 1360°C for a holding time of 20 hours to produce a sintered body. The total impurity content, relative density, volume resistivity, and average crystal grain size of the obtained sintered body were determined according to the methods described above. The results are shown in Table 1. As shown in Table 1, the total impurity content was 59.04 wtppm.

[0036] (Comparative Example 3) In having an average particle size (D50) of 2 μm or less ２ O ３ Ga powder (nominal purity: 4N), average particle size (D50) of 5 μm or less ２ O ３ In powder (nominal purity: 4N) and ZnO powder (nominal purity: 3N) with an average particle size (D50) of 1 μm or less were prepared, and were weighed and mixed so that the atomic ratio of In:Ga:Zn was 1:2:1. Next, this mixed powder was filled into a carbon die and sintered in an argon atmosphere at a temperature of 1180°C and a pressure of 250 kgf / cm. ２ Hot press sintering was carried out under the conditions of 0.15g / cm2, 0.15g / cm3, and 100g / cm4 for a holding time of 8 hours (no metal foil was used) to produce a disk-shaped sintered body with a diameter of 180 mm. The impurity content, relative density, volume resistivity, and average crystal grain size of the obtained sintered body were determined according to the methods described above. The results are shown in Table 1. As shown in Table 1, the total impurity content was 10 wtppm or more. In addition, In was present on the outer periphery of the sintered body in contact with the carbon member. ２ O ３ The reduction of In was observed. ２ O ３ The weight loss, which is an indicator of reduction, was 13.3%.

[0037] (Reference Example) In having an average particle size (D50) of 2 μm or less ２ O ３ Ga powder (nominal purity: 4N), average particle size (D50) of 5 μm or less ２ O ３ In powder (nominal purity: 4N) and ZnO powder (nominal purity: 3N) with an average particle size (D50) of 1 μm or less were prepared, and were weighed and mixed to obtain an In:Ga:Zn ratio of 1:2:1 (atomic ratio). Next, this mixed powder was filled into a carbon die covered with molybdenum (Mo) metal foil, and then sintered in an argon atmosphere at a temperature of 1180°C and a pressure of 250 kgf / cm. ２ The sintered body was subjected to hot press sintering (using metal foil) under the conditions of 1000 kJ / cm2, 1000 kJ / cm3, and 1000 kJ / cm4, and a holding time of 8 hours to prepare a disk-shaped sintered body having a diameter of 180 mm. The impurity content, relative density, volume resistivity, and average crystal grain size of the obtained sintered body were determined according to the methods described above. The results are shown in Table 1. As shown in Table 1, the use of metal foil reduced the amount of In ２ O ３ There was no reduction, but the total impurity content was 10 wtppm or more.

[0038] According to the present disclosure, it is possible to provide a sintered body containing indium (In), gallium (Ga), zinc (Zn), and oxygen (O), which has high purity and a high relative density, and a method for producing the same. A sputtering target using the sintered body of the present disclosure is useful as a transparent electrode for plasma displays, liquid crystal displays, organic EL displays, touch panels, solar cells, etc., and for forming an IGZO film as a semiconductor device (such as a TFT).

Claims

1. A sintered body containing indium (In), gallium (Ga), zinc (Zn) and oxygen (O), in which the total content of Li, Na, Al, Si, K, Cr, Fe, Cu, Sn, Pb and Zr is less than 10 wtppm, the Zr content is less than 1 wtppm, and the relative density is 95% or more.

2. The sintered body according to claim 1, wherein the average crystal grain size is 5 μm or less.

3. The sintered body according to claim 1 or 2, which has a volume resistivity of 10 mΩ·cm or less.

4. The sintered body according to any one of claims 1 to 3, which is in the form of a circular plate, a rectangular plate, or a cylinder.

5. A method for producing a sintered body according to any one of claims 1 to 4, comprising the steps of: ２ O ３ Powder, Ga ２ O ３ A method for producing a sintered body, comprising: mixing raw material powders of ZnO powder and ZnO powder; pressure-sintering the resulting mixed powder under vacuum or an inert gas atmosphere; and using a metal member during the pressure-sintering to prevent a reduction reaction between the sintering raw materials and the sintering equipment members.

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