A rare earth fluoride oxide ceramic for physical vapor deposition material source and preparation method thereof

Abstract

The present invention belongs to the field of rare earth fluoride oxide materials, and specifically relates to a rare earth fluoride oxide ceramic for a physical vapor deposition material source and a preparation method thereof, comprising the following steps: pre-treating raw material powders of rare earth oxide and rare earth fluoride to nanometer level; mixing the raw material powders according to a certain ratio, ball milling, drying, and sieving to form a mixed uniform powder; and then pressing into a ceramic body, and calcining at 400-800°C to obtain a rare earth fluoride oxide ceramic. The present invention adopts the method of refining the raw material powder to nanometer level in advance to ensure the consistency of the particle size of the raw material powder, so that in the subsequent solid phase reaction process, the rare earth fluoride oxide powder can be miniaturized and homogenized, and the low-temperature synthesis of the rare earth fluoride oxide can be realized. The synthesized rare earth fluoride oxide powder has the advantages of high crystallinity, small grain size and good uniformity, and can be directly used in the pressing process of physical vapor deposition target materials, without the need for ball milling, and effectively avoiding the introduction of pollutants.

Description

Technical Field

[0001] The present invention belongs to the field of rare earth oxyfluoride materials, and in particular, relates to a rare earth oxyfluoride ceramic used as a physical vapor deposition material source and a preparation method thereof. Background Art

[0002] With the rapid development of the semiconductor industry, plasma etching technology has been widely used in chip manufacturing. However, during the etching process, plasma will also cause erosion to the inside of the etcher. Usually, a protective coating is prepared on the surface of the component materials serving in the plasma environment, which can effectively alleviate the etching damage inside the etcher cavity.

[0003] Coating preparation methods can be divided into physical vapor deposition and chemical vapor deposition according to whether chemical reactions occur during the deposition process. Physical vapor deposition mainly involves heating or bombarding the target surface with energetic ions such as high-energy electrons, ions and photons to sputter out the corresponding gaseous atoms, ions and molecules, so as to condense into a film on the solid surface. Physical vapor deposition includes molecular beam epitaxy, pulsed laser deposition, magnetron sputtering (including DC magnetron sputtering, radio frequency magnetron sputtering and pulsed magnetron sputtering), electron beam deposition, evaporation coating, etc. Physical vapor deposition technology is widely used in the preparation of semiconductor equipment coatings because the prepared films have high hardness and strength, good thermal stability, stable chemical properties, dense organizational structure, pollution-free production process, and can achieve green manufacturing. According to the requirements of physical vapor deposition technology, the source of the material - the target material must meet the requirements of high purity, small grain size, good uniformity of composition and organizational structure, and high density.

[0004] Rare earth fluoride oxides have attracted much attention in the industry due to their excellent physical and chemical stability and good resistance to plasma etching. x F y (x>0, y>0)(RE=Sc、Y、La、Ce、Pr、Nd、Sm、Eu、Gd、Tb、Dy、Ho、Er、Tm、Yb or Lu), including stoichiometric ratio (REOF) and non-stoichiometric ratio Vernier type (RE n O n- 1F n+2 、REO 1-n F 1+2nAt present, the main methods for synthesizing rare earth fluoride oxide materials include high-temperature solid-phase method, precipitation method, sol-gel method, spray pyrolysis method, etc. The high-temperature solid-phase method is used because the product has few surface defects, good crystal quality, simple operation, less pollution, and high reaction efficiency. However, the traditional solid-phase synthesis method has the following problems: (1) The obtained powder has coarse grains and poor uniformity and cannot be directly used in the preparation process of physical vapor deposition target materials. It is necessary to add a further crushing and ball milling process. During the crushing and ball milling, additional dispersants need to be added, which makes the target material after ball milling complicated and easy to introduce new pollutants; (2) The sintering temperature of the traditional solid-phase synthesis method is relatively high (about 1000°C), and in the actual production process, there are problems of high equipment requirements and high energy consumption. Summary of the invention

[0005] In view of the problems of the prior art rare earth fluoride oxides such as coarse grains and poor uniformity that make them difficult to use as physical vapor deposition material sources, as well as high sintering temperatures in their preparation process, the present invention aims to provide a rare earth fluoride oxide ceramic for use as a physical vapor deposition material source and a preparation method thereof. The rare earth oxides and rare earth fluorides are pre-ball-milled and sand-milled to reduce the particle size and uniformity of the raw material powders, thereby reducing the solid-phase synthesis reaction temperature. The prepared rare earth fluoride oxide ceramics have high crystallinity, small grain size and good distribution uniformity, and can be directly used as a physical vapor deposition target without the need for ball-milling, thereby avoiding the introduction of pollutants.

[0006] Based on the above purpose, the technical solution adopted by the present invention is as follows:

[0007] In a first aspect, the present invention provides a method for preparing a rare earth oxyfluoride ceramic for a physical vapor deposition material source, comprising the following steps:

[0008] S1: Rare earth oxide powder and rare earth fluoride powder are respectively subjected to ball milling, sand milling, drying and sieving to obtain ultrafine rare earth oxide powder or ultrafine rare earth fluoride powder. The particle size of the ultrafine rare earth oxide powder or ultrafine rare earth fluoride powder is D 50 Less than 1 μm;

[0009] S2: mixing ultrafine rare earth oxide powder and ultrafine rare earth fluoride powder in a molar ratio of 1:(1-3), ball milling, drying and sieving to obtain a mixed powder material;

[0010] S3: pressing the mixed powder material into a ceramic body, and calcining at 400-800° C. to obtain rare earth fluoride oxide ceramics.

[0011] The present invention adopts high-energy ball milling to refine the raw material powders of rare earth oxides and rare earth fluorides to the nanometer level, thereby ensuring the consistency of the particle size of the raw material powders, so that in the subsequent solid-phase reaction process, the rare earth fluoride oxide powders can be miniaturized and homogenized, and the low-temperature synthesis of the rare earth fluoride oxide can be achieved. The synthesized rare earth fluoride oxide powder can be directly used in the pressing process of physical vapor deposition target materials without the need for ball milling, thereby effectively avoiding the introduction of pollutants.

[0012] The rare earth fluoride oxide ceramic material prepared by the method of the invention has small and uniform grain size and high crystallinity, and the grain size is 30-70nm.

[0013] Preferably, the ball milling in step S1 comprises the following steps:

[0014] Add water to rare earth oxide powder or rare earth fluoride powder to form a slurry with a solid content of 20-80%, add a dispersant to the slurry, use 10-30 mm zirconium oxide balls as grinding bodies, and ball mill at 60-120 r / min for 10-30 hours.

[0015] Preferably, the sanding in step S1 includes the following steps:

[0016] Water is added to the slurry after ball milling to adjust its solid content to 20% to 60%, and zirconium oxide beads with a particle size of 0.1 to 0.5 mm are used as grinding bodies, and sand milling is performed at 2000 to 3000 r / min for 0.5 to 3 hours.

[0017] The present invention adopts high-energy ball milling and sand milling of the raw material rare earth oxide and rare earth fluoride powders, which are sequentially processed by 10-30 mm zirconium oxide balls and 0.1-0.5 mm zirconium oxide beads as ball milling media, and the powders are crushed by the ball milling media during high-speed operation, and the particle size of the raw material powders is gradually reduced, and the uniformity of the powders is improved. The raw material powders after sand milling have uniform and fine particle size, high specific surface area, and high reaction activity. In addition, the method is simple to operate and easy to control, and can meet the high quality requirements of small material particle size, uniform distribution, and good sphericity, and can also meet the industrialization requirements of high efficiency, low loss, and low production process cost.

[0018] Preferably, the mixed ball milling in step S2 comprises the following steps:

[0019] Add dispersant to the mixture of ultrafine rare earth oxide powder and ultrafine rare earth fluoride powder, and ball mill at 200-600 r / min for 12-48 hours.

[0020] The mixed ball mill utilizes the impact of falling grinding bodies and the grinding action between the grinding bodies and the inner wall of the ball mill to crush and mix the materials. The present invention helps to reduce the subsequent sintering temperature and improve the uniformity of the fluoride oxide crystals after sintering by evenly mixing the ultrafine rare earth oxide powder and the ultrafine rare earth oxyfluoride powder.

[0021] Preferably, the dispersant is polymethacrylamide or ethanol; during the ball milling process in step S1, the amount of the dispersant added is 0.2% to 1% of the weight of the slurry; during the mixing ball milling process in step S2, the weight ratio of the mixed material to the dispersant is 1:(0 to 10).

[0022] Preferably, the drying in step S1 is: drying the sand-milled slurry at 80-140° C. for 12-36 hours; the drying in step S2 is: drying the mixed ball-milled material at 60-120° C. for 12-36 hours.

[0023] Preferably, the sieving in step S1 is to pass the dried material through a 50-200 mesh sieve; and the sieving in step 2 is to pass the dried material through a 50-200 mesh sieve.

[0024] In the present invention, the mixture of ultrafine rare earth oxide powder and ultrafine rare earth fluoride powder is ground and sieved, which is beneficial to the miniaturization and homogenization of the powder particle size, improves the uniformity of the mixed powder components, further reduces the solid phase synthesis reaction temperature, and improves the uniformity of the fluoride oxide crystals after sintering.

[0025] Preferably, the step S3 of pressing the mixed powder material into a ceramic body comprises the following steps:

[0026] The mixed powder material is pre-pressed at 3-10 MPa and then pressed into a ceramic body by cold isostatic pressing at 100-300 MPa.

[0027] Preferably, the rare earth fluoride oxides include ScOF, YOF, Y4O3F6, Y5O4F7, Y6O5F8, Y7O6F9, Y 17 O 14 F 23 , LaOF, La4O3F6, CeOF, Ce4O3F6, CeO6F2, PrOF, Pr4O3F6, NdOF, Nd4O3F6, SmOF, Sm4O3F6, SmO 0.7 F 1.6, EuOF, Eu4O3F6, Eu3O2F5, Eu5O4F7, GdOF, Gd4O3F6, Gd5O4F7, TbOF, Tb4O3F6, DyOF, HoOF, ErOF, Er3O2F5, Er4O3F6, Er5O4F7, TmOF, Tm4O3F6, YbOF, Yb4O3F6, Yb5O4F7, Yb6O5F8, LuOF, Lu3O2F5, Lu4O3F6, Lu5O4F7, and Lu7O6F9.

[0028] By utilizing the preparation method of the present invention, the above-mentioned rare earth fluoride oxide can be prepared by adjusting the raw material powder, the ratio of the raw material powder, the sintering temperature and the time.

[0029] In a second aspect, the present invention provides a rare earth fluoride oxide ceramic for a physical vapor deposition material source prepared by the above method, which has high crystallinity and a grain size of 30 to 70 nm.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] (1) The present invention pre-treats the raw materials of rare earth fluoride and rare earth oxide into nano-scale powders, thereby ensuring the consistency of the particle size of the raw material powders. Thus, in the subsequent solid-phase reaction process, the rare earth fluoride oxide powders can be miniaturized and homogenized, and the low-temperature synthesis of the rare earth fluoride oxide can be achieved. The synthesized rare earth fluoride oxide powders can be directly used in the pressing process of physical vapor deposition targets without the need for ball milling, thereby effectively avoiding the introduction of pollutants.

[0032] (2) In the entire preparation process of the present invention, except for the raw materials and dispersant (polymethacrylamide, water and ethanol), there are no other substances. Polymethacrylamide can be removed by calcination, and water and ethanol can be easily removed by drying. There will be no residual impurities. Therefore, the rare earth fluoride oxide prepared by the method of the present invention has high crystallinity.

[0033] (3) The rare earth fluoride oxide prepared by the method of the present invention not only has a high degree of crystallinity, but also has a small grain size and uniform distribution. It can be directly used as a source of physical vapor deposition material without the need for grinding treatment, thereby effectively avoiding the introduction of exogenous impurities. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 This is a process flow chart for preparing rare earth oxyfluoride ceramics of Examples 1 to 4;

[0035] Figure 2 This is a particle size distribution diagram of the yttrium oxide ultrafine powder prepared in Example 1;

[0036] Figure 3This is a particle size distribution diagram of the yttrium fluoride ultrafine powder prepared in Example 1;

[0037] Figure 4 This is a particle size distribution diagram of the raw material mixed powder prepared in Example 1;

[0038] Figure 5 This is the XRD pattern of the yttrium oxyfluoride ceramic prepared in Example 1;

[0039] Figure 6 This is a SEM image of the yttrium oxyfluoride ceramic prepared in Example 1;

[0040] Figure 7 XRD pattern of Y7O6F9 ceramic prepared in Example 2;

[0041] Figure 8 This is a particle size distribution diagram of the raw material mixed powder prepared in Example 3;

[0042] Fig. 9 This is the XRD pattern of the erbium oxyfluoride ceramic prepared in Example 3;

[0043] Fig.10 XRD pattern of the lanthanum oxyfluoride ceramic prepared in Example 4;

[0044] Fig.11 XRD pattern of the ceramic prepared in Comparative Example 1;

[0045] Fig.12 This is the particle size distribution diagram of the powder prepared in Comparative Example 2. DETAILED DESCRIPTION

[0046] In order to better illustrate the purpose, technical scheme and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments. It should be understood by those skilled in the art that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. The test methods used in the examples are conventional methods unless otherwise specified; the materials, reagents, etc. used can be obtained from commercial sources unless otherwise specified.

[0047] Example 1

[0048] This embodiment provides a method for preparing rare earth fluoride oxide ceramics for physical vapor deposition material source, and its process flow is as follows: Figure 1 As shown, the following steps are included:

[0049] (1) Preparation of Y2O3 ultrafine powder and YF3 ultrafine powder

[0050] The Y2O3 and YF3 powders with chemical purity ≥99.99% are placed in a ball mill respectively, and the solid content of the slurry is adjusted to 50% by adding deionized water. After adding 0.5wt% of a dispersant (polymethacrylic acid amine) to the slurry, the mixed material is passed through a roller mill with a zirconium oxide ball with a particle size of 20 to 25mm as a grinding body, and ball milled at 80r / min for 25 hours. The slurry after ball milling is poured into a sand mill, and the solid content of the slurry is adjusted to 30% by adding deionized water, and the zirconium oxide ball with a particle size of 0.3mm is used as a grinding body, and sand milled at 3000r / min for 0.5 hours. The sand-milled slurry is dried in a 100°C electric oven for 24 hours, and the sieved material is sieved through an 80-mesh sieve to obtain powders with uniform particle sizes: Y2O3 ultrafine powder and YF3 ultrafine powder.

[0051] (2) Preparation of yttrium oxyfluoride ceramics

[0052] The Y2O3 ultrafine powder and YF3 ultrafine powder obtained in step (1) are mixed in a ball mill at a molar ratio of 1:1.5, and anhydrous ethanol is added as a dispersant. The mass ratio of the mixed material powder and the dispersant is 1:2. The ball mill is placed in a planetary ball mill and ball milled at 450r / min for 24 hours. After the ball milling is completed, the material is placed in an electric constant temperature blast drying oven at 80°C and dried for 24 hours. The dried material is ground, and the material under the sieve is sieved through an 80-mesh sieve as the raw material mixed powder. The raw material mixed powder is preformed at 8MPa by a bidirectional ceramic hydraulic press, and then further cold isostatically pressed at 200MPa to form a ceramic body, and the ceramic body is roasted at 700°C for 6h to obtain a rare earth fluoride oxide ceramic.

[0053] The Y2O3 ultrafine powder and YF3 ultrafine powder obtained in step (1) of Example 1 were tested for particle size. Figure 2 and Figure 3 As shown, the particle size D of the powder was found 50 The raw material mixed powder obtained in step (2) of Example 1 was tested for particle size. Figure 4 As shown, the powder particle size D 50 =2.71μm, the powder particle size is small and evenly distributed. This shows that by high-energy ball milling of the raw materials, small and uniform raw material ultrafine powder can be obtained, and the grain size of the raw material mixture powder obtained by ball milling is also small and uniform.

[0054] The yttrium oxyfluoride ceramics prepared in Example 1 were subjected to XRD test. Figure 5 As shown in FIG. 1 , the XRD diffraction pattern of the ceramic shows a single rhombohedral YOF crystal without impurities. The grain size calculated by the Scherrer formula is 39.5 nm. The YOF ceramic prepared in Example 1 was scanned by SEM. Figure 6The above results show that the YOF ceramic material prepared by the method of this embodiment has high crystallinity, small and uniform grain size, and meets the requirements of the material source of physical vapor deposition technology.

[0055] Example 2

[0056] This embodiment provides a method for preparing rare earth fluoride oxide ceramics for physical vapor deposition material source, and its process flow is as follows: Figure 1 As shown, the following steps are included:

[0057] (1) Preparation of Y2O3 ultrafine powder and YF3 ultrafine powder

[0058] The Y2O3 and YF3 powders with chemical purity ≥99.99% are placed in a ball mill respectively, and the solid content of the slurry is adjusted to 40% by adding deionized water. After adding 0.8wt% of a dispersant (polymethacrylic acid amine) to the slurry, the mixed material is passed through a roller mill with a zirconium oxide ball with a particle size of 15 to 20mm as a grinding body, and ball milled at 100r / min for 20 hours. The slurry after ball milling is poured into a sand mill, and the solid content of the slurry is adjusted to 40% by adding deionized water, and the zirconium oxide ball with a particle size of 0.5mm is used as a grinding body, and sand milled at 2800r / min for 1.5 hours. The sand-milled slurry is dried in a 120°C electric oven for 18 hours, and the sieved material is sieved through a 100-mesh sieve to obtain ultrafine raw material powders with uniform particle sizes: Y2O3 ultrafine powder and YF3 ultrafine powder.

[0059] (2) Preparation of rare earth oxyfluoride ceramics

[0060] The Y2O3 and YF3 ultrafine raw material powders are mixed in a ball mill at a molar ratio of 1:2, and anhydrous ethanol is added as a dispersant. The mass ratio of the raw material to the dispersant is 1:3. The ball mill is placed in a planetary ball mill and ball milled at a speed of 500r / min for 18 hours. After the ball milling is completed, the material is placed in an electric constant temperature blast drying oven at 100°C and dried for 18 hours. The dried material is ground and sieved through a 100-mesh sieve. The sieved material is the raw material mixed powder material. The raw material mixed powder material is preformed at 10MPa by a bidirectional ceramic hydraulic press, and then further cold isostatically pressed at 250MPa to form a ceramic body. The ceramic body is calcined at 750°C for 6h to obtain rare earth fluoride oxide ceramics.

[0061] The rare earth fluoride oxide ceramics prepared in Example 2 were subjected to XRD test. Figure 7As shown, the XRD diffraction spectrum of the ceramic shows a single orthorhombic Y7O6F9 crystal without impurities, and the grain size calculated by the Scherrer formula is 32.1nm. This shows that the Y7O6F9 ceramic material prepared by the method of this embodiment has a controllable stoichiometric ratio, high crystallinity, and small grain size, and can be used as a material source for physical vapor deposition technology.

[0062] Example 3

[0063] This embodiment provides a method for preparing rare earth fluoride oxide ceramics for physical vapor deposition material source, and its process flow is as follows: Figure 1 As shown, the following steps are included:

[0064] (1) Preparation of Er2O3 ultrafine powder and ErF3 ultrafine powder

[0065] The Er2O3 and ErF3 powders with chemical purity ≥99.99% are placed in a ball mill respectively, and the solid content of the slurry is adjusted to 20% by adding deionized water. After adding 1wt% of a dispersant (polymethacrylic acid amine) to the slurry, the material is passed through a roller mill with a zirconium oxide ball with a particle size of 10 to 15mm as a grinding body, and ball milled at 120rmp / min for 10 hours. The slurry after ball milling is poured into a sand mill, and the solid content of the slurry is adjusted to 50% by adding deionized water, and the zirconium oxide ball with a particle size of 0.2mm is used as a grinding body, and sand milled at 2000r / min for 3 hours. The sand-milled slurry is dried in an electric oven at 80°C for 36 hours, and the sieved material is sieved through a 150-mesh sieve to obtain ultrafine raw material powders with uniform particle sizes: Er2O3 ultrafine powder and ErF3 ultrafine powder.

[0066] (2) Preparation of fluoride oxide ceramics

[0067] The Er2O3 and ErF3 ultrafine raw material powders were mixed in a ball mill at a molar ratio of 1:1.75, and anhydrous ethanol was added as a dispersant. The mass ratio of the raw material to the dispersant was 1:5. The ball mill was placed in a planetary ball mill and ball milled at a speed of 550r / min for 16 hours. After the ball milling was completed, it was placed in an electric constant temperature blast drying oven at 120°C for 12 hours, and the dried material was ground and sieved through a 150-mesh sieve. The sieved material was the raw material mixed powder. The raw material mixed powder was preformed at 5MPa by a bidirectional ceramic hydraulic press, and then further cold isostatically pressed at 150MPa to form a ceramic body. The ceramic body was calcined at 650°C for 6h to obtain erbium oxyfluoride ceramics.

[0068] The raw material mixed powder obtained in step (2) of Example 3 was tested for particle size. Figure 8 As shown, the powder particle size D 50=2.85μm, the powder particle size is small and evenly distributed. This shows that by high-energy ball milling of the raw materials, the grain size of the raw material mixed powder obtained is small and even.

[0069] The erbium oxyfluoride ceramics prepared in Example 3 were subjected to XRD test. Fig. 9 As shown, the XRD diffraction spectrum of the ceramic shows a single hexagonal ErOF crystal without impurities, and the grain size calculated by the Scherrer formula is 68.7nm. This shows that the ErOF ceramic material prepared by the method of this embodiment has a controllable stoichiometric ratio, high crystallinity, and small grain size, and can be used as a material source for physical vapor deposition technology.

[0070] Example 4

[0071] This embodiment provides a method for preparing rare earth fluoride oxide ceramics for physical vapor deposition material source, and its process flow is as follows: Figure 1 As shown, the following steps are included:

[0072] (1) Preparation of ultrafine powders La2O3 and LaF3

[0073] The La2O3 and LaF3 powders with chemical purity ≥99.99% are placed in a ball mill respectively, and the solid content of the slurry is adjusted to 80% by adding deionized water. After adding 0.2wt% dispersant (polymethacrylic acid amine) to the slurry, the material is passed through a roller mill with a zirconium oxide ball with a particle size of 25-30mm as a grinding body, and ball milled at 60rmp / min for 30 hours. The slurry after ball milling is poured into a sand mill, and the solid content of the slurry is adjusted to 60% by adding deionized water, and the zirconium oxide ball with a particle size of 0.1mm is used as a grinding body, and sand milled at 2600r / min for 2 hours. The sand-milled slurry is dried in an electric oven at 140°C for 12 hours, and the sieved material is sieved through an 80-mesh sieve to obtain ultrafine raw material powders with uniform particle sizes: La2O3 ultrafine powder and LaF3 ultrafine powder.

[0074] (2) Preparation of lanthanum oxyfluoride ceramics

[0075] The ultrafine raw material powders of La2O3 and LaF3 were mixed in a ball mill at a molar ratio of 1:1.25, and anhydrous ethanol was added as a dispersant. The mass ratio of the raw material to the dispersant was 1:8. The ball mill was placed in a planetary ball mill and ball milled at 300r / min for 40 hours. After the ball milling was completed, it was placed in an electric constant temperature blast drying oven at 60°C for 36 hours, the dried material was ground, sieved through an 80-mesh sieve, and the obtained sieve was preformed at 3MPa by a bidirectional ceramic hydraulic press, and then further cold isostatically pressed at 250MPa into a ceramic body, and the ceramic body was calcined at 550°C for 6h to obtain lanthanum fluoride oxide ceramics.

[0076] The lanthanum oxyfluoride ceramics prepared in Example 4 were subjected to XRD test. Fig.10 As shown, the ceramic XRD diffraction spectrum shows a single tetragonal LaOF crystal without impurities, and the grain size calculated by the Scherrer formula is 39.9 nm. This shows that the LaOF ceramic material prepared by the method of the present invention has a controllable stoichiometric ratio, high crystallinity, and small grain size, and can be used as a material source for physical vapor deposition technology.

[0077] Comparative Example 1

[0078] The difference between this comparative example and Example 1 is that the calcination temperature of the yttrium oxyfluoride ceramic is adjusted from 700° C. to 350° C. or 850° C., respectively, and the remaining parts not mentioned are the same as those in Example 1.

[0079] The ceramic material obtained in Comparative Example 1 was subjected to XRD test. Fig.11 As shown. The XRD diffraction spectrum shows that when the calcination temperature is 350°C, the yttrium oxyfluoride phase is not formed because the calcination temperature is too low, and the yttrium oxyfluoride ceramic cannot be obtained. When the calcination temperature is 850°C, rhombohedral YOF crystals are formed, but because the calcination temperature is too high, some F is lost, resulting in the appearance of the Y2O3 crystal phase, and a single yttrium oxyfluoride ceramic material without impurities is not obtained.

[0080] The present invention utilizes high-energy ball milling to pretreat raw material powders and utilizes ball milling to prepare fluoride oxide powders, which is beneficial to miniaturization and uniformity of powder particle size, increase of specific surface area, and improvement of reaction activity, thereby reducing calcination temperature. The suitable calcination temperature range of the present invention is 400-800°C.

[0081] Comparative Example 2

[0082] The difference between this comparative example and Example 1 is that the Y2O3 and YF3 powders in this comparative example are not subjected to the pretreatment process of high-energy ball milling in step (1). The initial raw materials Y2O3 and YF3 powders are directly mixed in a ball milling jar at a molar ratio of 1:1.5, anhydrous ethanol is added as a dispersant, and the mass ratio of the raw materials to the dispersant is 1:3. The ball milling jar is placed in a planetary ball mill for ball milling for 24 hours. After the ball milling is completed, the material is placed in an electric constant temperature blast drying oven at 80°C and dried for 24 hours. The dried material is ground and sieved through an 80-mesh sieve to obtain yttrium oxyfluoride powder material.

[0083] The yttrium oxyfluoride powder prepared in Comparative Example 2 was tested for particle size. Fig.12 As shown, the powder particle size D 50 =154.84μm, D 90 =343.07μm, the powder particle size is coarse and the distribution is very uneven, and it cannot be directly used in the subsequent preparation process of ceramic targets.

[0084] From the results of Comparative Example 2, it can be seen that the process of pretreating the raw materials by high-energy ball milling in the present invention is beneficial to the miniaturization and homogenization of the powder particle size, further reducing the solid phase synthesis reaction temperature, and improving the uniformity of the mixed powder components, so that the prepared fluoride oxide powder material can be directly used for the preparation of target materials for physical vapor deposition material sources.

Claims

1. A method for preparing rare earth oxyfluoride ceramics for physical vapor deposition material source, characterized in that: The steps include: S1: ball milling, sand milling, drying and sieving the rare earth oxide powder and the rare earth fluoride powder to obtain ultrafine rare earth oxide powder or ultrafine rare earth fluoride powder, wherein the particle size of the ultrafine rare earth oxide powder or the ultrafine rare earth fluoride powder is D 50 Less than 1 μm; S2: mixing ultrafine rare earth oxide powder and ultrafine rare earth fluoride powder in a molar ratio of 1:(1-3), ball milling, drying and sieving to obtain a mixed powder material; S3: pressing the mixed powder material into a ceramic body, and calcining at 400-800° C. to obtain rare earth fluoride oxide ceramics; The rare earth fluoride oxide ceramic has high crystallinity and a grain size of 30 to 70 nm; The rare earth fluoride oxides include ScOF, YOF, Y4O3F6, Y5O4F7, Y6O5F8, Y7O6F9, Y 17 O 14 F 23 , LaOF, La4O3F6, CeOF, Ce4O3F6, CeO6F2, PrOF, Pr4O3F6, NdOF, Nd4O3F6, SmOF, Sm4O3F6, SmO 0.7 F 1.6 , EuOF, Eu4O3F6, Eu3O2F5, Eu5O4F7, GdOF, Gd4O3F6, Gd5O4F7, TbOF, Tb4O3F6, DyOF, HoOF, ErOF, Er3O2F5, Er4O3F6, Er5O4F7, TmOF, Tm4O3F6, YbOF, Yb4O3F6, Yb5O4F7, Yb6O5F8, LuOF, Lu3O2F5, Lu4O3F6, Lu5O4F7, and Lu7O6F9.

2. The method for preparing rare earth oxyfluoride ceramics for physical vapor deposition material source according to claim 1, characterized in that: The ball milling in step S1 comprises the following steps: Add water to rare earth oxide powder or rare earth fluoride powder to form a slurry with a solid content of 20% to 80%, add a dispersant to the slurry, use 10 to 30 mm zirconium oxide balls as grinding bodies, and ball mill at 60 to 120 r / min for 10 to 30 hours.

3. The method for preparing rare earth oxyfluoride ceramics for physical vapor deposition material source according to claim 2, characterized in that: The sanding in step S1 comprises the following steps: Water is added to the slurry after ball milling to adjust its solid content to 20% to 60%, and zirconium oxide beads with a particle size of 0.1 to 0.5 mm are used as grinding bodies, and sand milling is performed at 2000 to 3000 r / min for 0.5 to 3 hours.

4. The method for preparing rare earth oxyfluoride ceramics for physical vapor deposition material source according to claim 1, characterized in that: The mixed ball milling in step S2 comprises the following steps: Add dispersant to the mixture of ultrafine rare earth oxide powder and ultrafine rare earth fluoride powder, and ball mill at 200-600 r / min for 12-48 hours.

5. The method for preparing rare earth oxyfluoride ceramics for physical vapor deposition material source according to claim 2 or 4, characterized in that: The dispersant is polymethyl methacrylate or ethanol; in the ball milling process of step S1, the added amount of the dispersant is 0.2% to 1% of the slurry weight; in the mixed ball milling process of step S2, the weight ratio of the mixed material to the dispersant is 1: (0 to 10).

6. The method for preparing rare earth oxyfluoride ceramics for physical vapor deposition material source according to claim 1, characterized in that: The drying in step S1 is: drying the sand-milled slurry at 80-140° C. for 12-36 hours; the drying in step S2 is: drying the mixed ball-milled material at 60-120° C. for 12-36 hours.

7. The method for preparing rare earth oxyfluoride ceramics for physical vapor deposition material source according to claim 1, characterized in that: The sieving in step S1 is to pass the dried material through a 50-200 mesh sieve; the sieving in step 2 is to pass the dried material through a 50-200 mesh sieve.

8. The method for preparing rare earth oxyfluoride ceramics for physical vapor deposition material source according to claim 1, characterized in that: The step S3 of pressing the mixed powder material into a ceramic body comprises the following steps: The mixed powder material is pre-pressed at 3-10 MPa and then pressed into a ceramic body by cold isostatic pressing at 100-300 MPa.

9. A rare earth fluoride oxide ceramic for physical vapor deposition material source, characterized in that: Prepared by the method of claim 1, the rare earth fluoride oxide ceramic used as the physical vapor deposition material source has high crystallinity and a grain size of 30 to 70 nm.

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