ICO sputtering target material with fine and uniform crystal grains and preparation method of ICO sputtering target material

Abstract

The embodiment of the invention discloses an ICO sputtering target material with fine and uniform crystal grains and a preparation method of the ICO sputtering target material. The method comprises the steps that raw material powder is prepared into a high-density target material biscuit, and the target material biscuit is subjected to degreasing treatment; the degreasing temperature is 500-750 DEG C, the heating rate is 0.5-2 DEG C / min, and the heat preservation time is 180-300 min; continuously raising the temperature to a first sintering temperature for first sintering; the first sintering temperature ranges from 1450 DEG C to 1600 DEG C, the heating rate ranges from 2 DEG C / min to 4 DEG C / min, and the sintering time ranges from 20 min to 180 min; cooling to a second sintering temperature for second sintering; the second sintering temperature is 10-100 DEG C lower than the first sintering temperature, the cooling rate is 2-5 DEG C / min, and the sintering time is 1200-1800 min; cooling to a third sintering temperature and carrying out third sintering; the third sintering temperature is 800-1000 DEG C, the cooling rate is 0.5-2 DEG C / min, and the sintering time is 180-360 minutes; cooling to 200 DEG C at a cooling rate of 2-5 DEG C / min; and then naturally cooling to room temperature to obtain the ICO target material with fine and uniform crystal grains.

Description

Technical Field

[0001] The invention belongs to the technical field of sputtering target materials, and in particular relates to an ICO sputtering target material with fine and uniform grains and a preparation method thereof. Background Art

[0002] Transparent Conductive Oxides (TCOs) are indispensable materials in solar cells and other electronic devices, and their performance directly affects the efficiency and stability of the devices. At present, the mainstream TCO films on the market mainly include three systems: transparent conductive oxide films based on tin oxide (SnO2), transparent conductive oxide films based on indium oxide (In2O3), and transparent conductive oxide films based on zinc oxide (ZnO). Among them, Cerium Doped Indium Oxide (ICO), as an emerging In2O3-based transparent conductive oxide film, has attracted widespread attention due to its excellent electrical and optical properties.

[0003] Cerium oxide nanomaterial is a metal oxide of wide bandgap N-type semiconductor with high light transmittance and controllable electrical properties. The electrical properties of In2O3 can be optimized by regulating the In2O3 doping or preparation process.

[0004] The preparation of high-performance ICO targets is crucial for the preparation of high-performance ICO films. However, there are currently no relevant reports in the field of ICO targets, and there is a lack of relevant technologies for preparing ICO targets with fine and uniform grains. Summary of the invention

[0005] In view of this, on the one hand, some embodiments disclose a method for preparing an ICO sputtering target with fine and uniform grains, comprising the steps of:

[0006] S1. Mixing raw material powder, dispersant and water to prepare raw material slurry; wherein the raw material powder consists of indium oxide powder and cerium oxide powder;

[0007] S2, the raw material slurry is subjected to ball milling treatment;

[0008] S3, the raw material slurry after ball milling is subjected to sand milling;

[0009] S4, spray granulating the raw material slurry after sand milling to obtain raw material granulated powder;

[0010] S5, the raw material granulated powder is molded to obtain a target blank;

[0011] S6, the target material blank is subjected to cold isostatic pressing to obtain a high-density target material blank;

[0012] S7, sintering the high-density target blank to obtain an ICO target with fine and uniform grains;

[0013] Among them, the sintering of high-density target blanks includes:

[0014] S701, slowly heating from room temperature to degreasing temperature for degreasing treatment; wherein the degreasing temperature is 500-750°C, the heating rate is 0.5-2°C / min, and the degreasing holding time is 180-300min;

[0015] S702, after the debinding stage is completed, continue heating from the debinding temperature and quickly raise the temperature to the first sintering temperature for the first sintering; wherein the first sintering temperature is 1450-1600° C., the heating rate is 2-4° C. / min, and the first sintering time is 20-180 min;

[0016] S703, after the first sintering is completed, the temperature is rapidly lowered from the first sintering temperature to the second sintering temperature for a second sintering; wherein the second sintering temperature is 10-100°C lower than the first sintering temperature, the cooling rate is 2-5°C / min, and the second sintering time is 1200-1800min;

[0017] S704, after the second sintering is completed, the temperature is slowly lowered from the second sintering temperature to the third sintering temperature for the third sintering; wherein the third sintering temperature is 800-1000°C, the cooling rate is controlled to be 0.5-2°C / min, and the third sintering time is 180-360min;

[0018] S705. After the third sintering is completed, the temperature is lowered to 200°C at a cooling rate of 2-5°C / min; and then the temperature is naturally lowered to room temperature.

[0019] Furthermore, in some embodiments of the method for preparing an ICO sputtering target with fine and uniform grains, in step S1, the mass ratio of indium oxide powder to cerium oxide powder is 90-99.5:0.5-10, the mass ratio of dispersant to raw material powder is 0.5-2:100, and the mass content of water in the raw material slurry is 50-70%.

[0020] Some embodiments disclose a method for preparing an ICO sputtering target with fine and uniform grains. In step S2, ball milling is carried out on a ball mill. The ball milling time is controlled at 6 to 12 hours. The rotation speed of the ball mill is 250 to 320 r / min. The mass ratio of zirconia grinding balls to raw material slurry is controlled at 2.5 to 4:1. The diameters of the grinding balls are selected to be 1 mm, 3 mm and 6 mm, and the mass ratios of the grinding balls are 1:1:1 respectively.

[0021] In some embodiments of the method for preparing an ICO sputtering target with fine and uniform grains, in step S3, the sand grinding method includes:

[0022] Transfer the uniformly mixed slurry to a sand mill for sand grinding;

[0023] The sand mill runs at low speed for low-speed sand grinding, with a speed of 1500-2000r / min;

[0024] Then the sand mill runs at high speed for high-speed sand grinding, with a speed of 2000-2500r / min;

[0025] Finally, the sand mill runs at a low speed for low-speed sand grinding, with a speed of 1500-2000r / min;

[0026] The total time of high-speed sand milling is controlled at 30 to 75 minutes, the total time of low-speed sand milling is controlled at 10 to 15 minutes, the temperature of the slurry is controlled to be maintained at 20 to 40°C during sand milling, and polyvinyl alcohol is added to the slurry as a binder between 5 and 15 minutes before the end of the sand milling process, and the mass ratio of the binder to the raw material powder is 0.2 to 2:100.

[0027] In the method for preparing an ICO sputtering target with fine and uniform grains disclosed in some embodiments, in step S4, spray granulation is performed on a spray granulator, the temperature of the spray granulator is 190 to 250° C., and the centrifugal frequency is 30 to 45 Hz.

[0028] In some embodiments of the method for preparing an ICO sputtering target with fine and uniform grains, in step S5, the compression molding is performed in a hydraulic press, the pressure of the hydraulic press is set to 40-70 MP, and the holding time is 3-8 min.

[0029] In some embodiments of the method for preparing an ICO sputtering target with fine and uniform grains, in step S6, cold isostatic pressing is performed in a cold isostatic press, the pressure of the cold isostatic press is set to 190-250 MP, and the holding time is 3-8 min.

[0030] On the other hand, some embodiments disclose an ICO sputtering target with fine and uniform grains, which is obtained by the preparation method of the ICO sputtering target with fine and uniform grains disclosed in the embodiments of the present invention. The relative density of the ICO sputtering target with fine and uniform grains reaches 98.07%, and the average grain size is 2.62μm.

[0031] The embodiment of the present invention discloses a method for preparing an ICO sputtering target with fine and uniform grains. The obtained ICO sputtering target with fine and uniform grains has fine grains, an average grain size of 2.62 μm, high density, and a relative density of 98.07%, which is conducive to the preparation of high-performance ICO films and has good application prospects in the field of preparation of ICO sputtering targets with fine and uniform grains. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 The microstructure of the ICO sputtering target in Example 1;

[0033] Figure 2 is the XRD pattern of the ICO sputtering target in Example 1;

[0034] Figure 3 This is the organizational morphology of the ICO sputtering target in Comparative Example 1. DETAILED DESCRIPTION

[0035] The word "embodiment" used herein as an "exemplary" does not necessarily mean that any embodiment described is superior or better than other embodiments. Performance index tests in the embodiments of the present invention are performed using conventional test methods in the art unless otherwise specified. It should be understood that the terms described in the embodiments of the present invention are only used to describe specific implementation methods and are not intended to limit the contents disclosed in the embodiments of the present invention.

[0036] Unless otherwise specified, the technical and scientific terms used herein have the same meanings as commonly understood by ordinary technicians in the technical field to which the embodiments of the present invention belong; other experimental methods and technical means not specifically specified in the embodiments of the present invention refer to experimental methods and technical means commonly used by ordinary technicians in the field.

[0037] The terms "substantially" and "approximately" used herein are used to describe small fluctuations. For example, they can refer to less than or equal to ±5%, such as less than or equal to ±2%, such as less than or equal to ±1%, such as less than or equal to ±0.5%, such as less than or equal to ±0.2%, such as less than or equal to ±0.1%, such as less than or equal to ±0.05%. The numerical data represented or presented in the range format herein are used only for convenience and brevity, and should therefore be flexibly interpreted as including not only the values ​​clearly listed as the limits of the range, but also all independent values ​​or sub-ranges contained in the range. For example, the numerical range of "1-5%" should be interpreted as including not only the clearly listed values ​​of 1% to 5%, but also the independent values ​​and sub-ranges within the range shown. Therefore, independent values ​​such as 2%, 3.5% and 4% and sub-ranges such as 1%-3%, 2%-4% and 3%-5% are included in this numerical range. This principle also applies to the range of only one numerical value. In addition, such an interpretation applies regardless of the width of the range or the characteristics described.

[0038] In this document, including in the claims, transitional words such as "comprises," "includes," "with," "having," "containing," "involving," "accommodating," etc. are understood to be open-ended, i.e., meaning "including but not limited to." Only the transitional words "consisting of" and "composed of" are closed transitional words.

[0039] In order to better illustrate the present invention, numerous specific details are provided in the specific examples below. It should be understood by those skilled in the art that the present invention can be implemented without certain specific details. In the embodiments, some methods, means, instruments, equipment, etc. well known to those skilled in the art are not described in detail in order to highlight the gist of the present invention.

[0040] Under the premise of no conflict, the technical features disclosed in the embodiments of the present invention may be arbitrarily combined, and the resulting technical solutions belong to the contents disclosed in the embodiments of the present invention.

[0041] In some embodiments, some examples disclose a method for preparing an ICO sputtering target with fine and uniform grains, comprising the steps of:

[0042] S1. Mixing raw material powder, dispersant and water to prepare raw material slurry; wherein the raw material powder is composed of indium oxide powder and cerium oxide powder; in some embodiments, the mass ratio of indium oxide powder to cerium oxide powder is 90-99.5:0.5-10, the mass ratio of dispersant to raw material powder is 0.5-2:100, and the mass content of water in the raw material slurry is 50-70%;

[0043] S2. The raw material slurry is subjected to ball milling treatment; in some embodiments, the ball milling treatment of the raw material slurry is carried out on a ball mill, the ball milling time is controlled at 6 to 12 hours, the speed of the ball mill is 250 to 320 r / min, the mass ratio of zirconia grinding balls to the raw material slurry is controlled at 2.5 to 4:1, the diameters of the grinding balls are selected from 1 mm, 3 mm and 6 mm, and the mass ratios of the grinding balls are 1:1:1 respectively;

[0044] S3, the raw material slurry after ball milling is subjected to sand milling. In some embodiments, the sand milling method of the raw material slurry includes:

[0045] Transfer the uniformly mixed slurry to a sand mill for sand grinding;

[0046] The sand mill runs at low speed for low-speed sand grinding, with a speed of 1500-2000r / min;

[0047] Then the sand mill runs at high speed for high-speed sand grinding, with a speed of 2000-2500r / min;

[0048] Finally, the sand mill runs at a low speed for low-speed sand grinding, with a speed of 1500-2000r / min;

[0049] The total time of high-speed sand milling is controlled within 30 to 75 minutes, the total time of low-speed sand milling is controlled within 10 to 15 minutes, the temperature of the slurry is controlled to be maintained at 20 to 40° C., and polyvinyl alcohol is added to the slurry as a binder 5 to 15 minutes before the end of the sand milling process, and the mass ratio of the binder to the raw material powder is 0.2 to 2:100;

[0050] Generally, during the ball milling and sand milling process of the raw material slurry, the raw material powder can be pre-treated. By controlling the rotation speed, ball-to-material ratio, and slurry temperature and other parameters, a slurry with fine raw material powder particles and uniform mixing is obtained, which provides favorable conditions for preparing granulated powder with good sphericity and uniform particle size in the next step of spray granulation, and further provides a good foundation for obtaining a target blank with uniform structure and high density.

[0051] S4, spray granulating the raw material slurry after sand milling to obtain raw material granulated powder; in some embodiments, the spray granulation is performed on a spray granulator, the temperature of the spray granulator is 190 to 250° C., and the centrifugal frequency is 30 to 45 Hz;

[0052] S5, the raw material granulated powder is molded to obtain a target blank; in some embodiments, the molding is performed in a hydraulic press, the pressure of the hydraulic press is set to 40-70 MP, and the holding time is 3-8 min;

[0053] S6. The target material blank is subjected to cold isostatic pressing to obtain a high-density target material blank. In some embodiments, the cold isostatic pressing is performed in a cold isostatic press, the pressure of the cold isostatic press is set to 190-250 MP, and the holding time is 3-8 min.

[0054] S7, sintering the high-density target blank to obtain an ICO target with fine and uniform grains; generally, the obtained ICO target has a high content of indium oxide and a low content of cerium oxide, so the ICO target can be called a cerium oxide-doped indium oxide ceramic target;

[0055] Among them, the sintering of high-density target blanks includes:

[0056] S701, slowly heating from room temperature to degreasing temperature for degreasing treatment; wherein the degreasing temperature is 500-750°C, the heating rate is 0.5-2°C / min, and the degreasing holding time is 180-300min;

[0057] S702, after the debinding stage is completed, continue heating from the debinding temperature and quickly raise the temperature to the first sintering temperature for the first sintering; wherein the first sintering temperature is 1450-1600° C., the heating rate is 2-4° C. / min, and the first sintering time is 20-180 min;

[0058] S703, after the first sintering is completed, the temperature is rapidly lowered from the first sintering temperature to the second sintering temperature for a second sintering; wherein the second sintering temperature is 10-100°C lower than the first sintering temperature, the cooling rate is 2-5°C / min, and the second sintering time is 1200-1800min;

[0059] S704, after the second sintering is completed, the temperature is slowly lowered from the second sintering temperature to the third sintering temperature for the third sintering; wherein the third sintering temperature is 800-1000°C, the cooling rate is controlled to be 0.5-2°C / min, and the third sintering time is 180-360min;

[0060] S705. After the third sintering is completed, the temperature is lowered to 200°C at a cooling rate of 2-5°C / min; and then the temperature is naturally lowered to room temperature.

[0061] Generally, in the sintering process, the uniformly organized target blank undergoes a multi-step sintering process, and the target blank can be completely degreased at the degreasing temperature. The degreased target blank is then heated to a relatively high first sintering temperature, at which the sintered body obtains a certain relative density, and then rapidly cooled to a lower second sintering temperature, which can effectively inhibit the further growth of the grains, and is kept at this temperature for a long time to achieve the homogenization of fine grains; finally, the temperature is slowly cooled to the third sintering temperature, and keeping at this temperature can reduce the thermal stress inside the target material, and reduce the risk of cracks and subsequent cracking inside the target material. This sintering method helps to promote rapid densification in the early stage, and inhibit excessive growth of grains in the later stage, thereby obtaining a target material with fine grains.

[0062] Some embodiments disclose an ICO sputtering target with fine and uniform grains, which is obtained by the preparation method of the ICO sputtering target with fine and uniform grains disclosed in the embodiments of the present invention. The relative density of the ICO sputtering target reaches 98.07%, and the average grain size is 2.62μm. The microstructure of the target has a significant effect on the performance of the film. Generally, when the grain size of the ICO sputtering target is small, the small grain size helps to improve the uniformity of electrical and optical properties compared to the target with a larger grain size. In addition, a larger grain size may increase the risk of cracking of the target during the sputtering process, which not only reduces the utilization rate of the target, but also increases the production cost of the enterprise. In addition, the uniformity of the grains inside the target is also crucial to the performance of the film obtained by sputtering. If the grain size of the target is uneven, it will directly affect the uniformity of the film, and then affect the optoelectronic properties of the film and its application effect.

[0063] The technical details are further illustrated below in conjunction with embodiments.

[0064] Example 1

[0065] In Example 1, the method for preparing an ICO sputtering target with fine and uniform grains includes:

[0066] S1. Weigh the raw material powder and the dispersant according to the set ratio and mix them evenly to obtain a raw material slurry; wherein the mass of cerium oxide powder in the raw material powder accounts for 2.5%, the mass of indium oxide powder accounts for 97.5%, the mass ratio of dispersant ammonium polyacrylate to raw material powder is 1:100, and pure water accounts for 60% of the total mass of the raw material slurry;

[0067] S2, ball milling treatment: the raw material slurry is placed in a ball milling jar with zirconia grinding balls, and the jar is placed on a ball mill to start ball milling; the ball milling time is controlled at 8 hours, the speed of the ball mill is 250r / min, the mass ratio of zirconia grinding balls to raw material slurry is controlled at 2.5:1, and the diameters of the selected grinding balls are 1mm, 3mm and 6mm, respectively, and the mass ratio is 1:1:1;

[0068] S3, sand milling: after the ball milling is completed, the slurry in the ball milling tank is taken out and transferred to a sand mill for sand milling. The sand milling time is controlled at 60 minutes. The speed of the sand mill is first operated at a low speed, then the speed is increased, and then it is operated at a high speed, and finally it is operated at a low speed until the end. The speed control is as follows: the speed of the low speed operation is set to 1600r / min, and the speed of the high speed operation is set to 2300r / min; the total operation time of the low speed sand milling is 10 minutes, and the operation time of the high speed sand milling is 50 minutes; the temperature of the slurry is controlled to be maintained at 20°C during sand milling. 10 minutes before the end of the sand milling treatment, polyvinyl alcohol is added to the slurry as a binder, and the content of the binder accounts for 0.5% of the mass of the powder;

[0069] S4, spray granulation: the raw material slurry obtained by sand grinding is placed in a beaker, and an appropriate amount of defoaming agent n-octanol is added thereto to eliminate bubbles in the slurry, so as to facilitate the subsequent acquisition of granulated powder with good fluidity and close to spherical shape; the slurry is then pumped into a granulator for spray granulation; wherein the temperature of the spray granulator is set to 200°C, and the centrifugal frequency of the atomizer is 45Hz;

[0070] S5. Compression molding: Weigh a certain mass of granulated powder and put it into a steel mold and gently vibrate the mold to make the powder more evenly distributed and compact in the mold, and use a hydraulic press for compression molding; the pressure of the hydraulic press is set to 50MP, and the pressure holding time is 5min; after the pressure holding is completed, demold the target blank to obtain;

[0071] S6, cold isostatic pressing: put the target blank into a vacuum bag, put it into a vacuum packaging machine for vacuum treatment, and then put the packaged target blank into a cold isostatic press for cold isostatic pressing. The pressure of the cold isostatic press is set to 250MP, and the pressure holding time is 5min to obtain a high-density target blank with uniform density.

[0072] S7, target sintering:

[0073] S701, slowly heating from room temperature to degreasing temperature for degreasing treatment; wherein the degreasing temperature is 750°C, the heating rate is 1°C / min, and the degreasing holding time is 300min;

[0074] S702, after the debinding stage is completed, continue heating from the debinding temperature and quickly raise the temperature to the first sintering temperature for the first sintering; wherein the first sintering temperature is 1560°C, the heating rate is 3°C / min, and the first sintering time is 30min;

[0075] S703, after the first sintering is completed, the temperature is rapidly lowered from the first sintering temperature to the second sintering temperature for the second sintering; wherein the second sintering temperature is 1520°C, which is 40°C lower than the first sintering temperature, the cooling rate is 2°C / min, and the second sintering time is 1500min;

[0076] S704, after the second sintering is completed, the temperature is slowly lowered from the second sintering temperature to the third sintering temperature for the third sintering; wherein the third sintering temperature is 900°C, the cooling rate is controlled to be 1°C / min, and the third sintering time is 180min;

[0077] S705. After the third sintering is completed, the temperature is lowered to 200°C at a cooling rate of 2°C / min; then the temperature is naturally lowered to room temperature.

[0078] Figure 1 is the organizational morphology of the ICO sputtering target in Example 1, Figure 2 is the XRD spectrum of the ICO sputtering target in Example 1; the density of the ICO sputtering target prepared in Example 1 is 7.0408 g / cm 3 The relative density is 98.07%, the grain size distribution is uniform, and the average grain size is 2.62μm, which effectively improves the grain size control problem of ICO target material.

[0079] Example 2

[0080] In Example 2, the method for preparing an ICO sputtering target with fine and uniform grains includes:

[0081] S1. Weigh the raw material powder and the dispersant according to the set ratio and mix them evenly to obtain a raw material slurry; wherein the mass of cerium oxide powder in the raw material powder accounts for 1%, the mass of indium oxide powder accounts for 99%, the mass ratio of dispersant ammonium polyacrylate to raw material powder is 0.5:100, and pure water accounts for 60% of the total mass of the raw material slurry;

[0082] S2, ball milling treatment: the raw material slurry is placed in a ball milling jar with zirconia grinding balls, and the jar is placed on a ball mill to start ball milling; the ball milling time is controlled at 8 hours, the speed of the ball mill is 260r / min, the mass ratio of zirconia grinding balls to raw material slurry is controlled at 3:1, and the diameters of the selected grinding balls are 1mm, 3mm and 6mm, respectively, and the mass ratio is 1:1:1;

[0083] S3, sand milling: after the ball milling is completed, the slurry in the ball milling tank is taken out and transferred to a sand mill for sand milling. The sand milling time is controlled at 70 minutes. The speed of the sand mill is first operated at a low speed, then the speed is increased, and then it is operated at a high speed, and finally it is operated at a low speed until the end. The speed control is as follows: the speed of the low speed operation is set to 1700r / min, and the speed of the high speed operation is set to 2400r / min. The total operation time of the low speed sand milling is 10 minutes, and the operation time of the high speed sand milling is 60 minutes. During the sand milling, the temperature of the slurry is controlled to be maintained at 30°C. 15 minutes before the end of the sand milling treatment, polyvinyl alcohol is added to the slurry as a binder, and the content of the binder accounts for 1% of the mass of the powder.

[0084] S4, spray granulation: the raw material slurry obtained by sand grinding is placed in a beaker, and an appropriate amount of defoaming agent n-octanol is added thereto to eliminate bubbles in the slurry, so as to facilitate the subsequent acquisition of granulated powder with good fluidity and close to spherical shape; the slurry is then pumped into a granulator for spray granulation; wherein the temperature of the spray granulator is set to 240°C, and the centrifugal frequency of the atomizer is 45Hz;

[0085] S5. Compression molding: Weigh a certain mass of granulated powder and put it into a steel mold and gently vibrate the mold to make the powder more evenly distributed and compact in the mold, and use a hydraulic press for compression molding; the pressure of the hydraulic press is set to 45MP, and the pressure holding time is 5min; after the pressure holding is completed, demold the target blank to obtain;

[0086] S6, cold isostatic pressing: put the target blank into a vacuum bag, put it into a vacuum packaging machine for vacuum treatment, and then put the packaged target blank into a cold isostatic press for cold isostatic pressing. The pressure of the cold isostatic press is set to 250MP, and the pressure holding time is 6 minutes to obtain a high-density target blank with uniform density.

[0087] S7, target sintering:

[0088] S701, slowly heating from room temperature to degreasing temperature for degreasing treatment; wherein the degreasing temperature is 700°C, the heating rate is 1.5°C / min, and the degreasing holding time is 250min;

[0089] S702, after the debinding stage is completed, continue heating from the debinding temperature to the first sintering temperature for the first sintering; wherein the first sintering temperature is 1550°C, the heating rate is 2.5°C / min, and the first sintering time is 20min;

[0090] S703, after the first sintering is completed, the temperature is rapidly reduced from the first sintering temperature to the second sintering temperature for the second sintering; wherein the second sintering temperature is 1500°C, which is 50°C lower than the first sintering temperature, the cooling rate is 2.5°C / min, and the second sintering time is 1500min;

[0091] S704, after the second sintering is completed, the temperature is slowly lowered from the second sintering temperature to the third sintering temperature for the third sintering; wherein the third sintering temperature is 1000°C, the cooling rate is controlled to be 0.5°C / min, and the third sintering time is 210min;

[0092] S705. After the third sintering, the temperature is lowered to 200°C at a cooling rate of 3.5°C / min; then the temperature is naturally lowered to room temperature.

[0093] The grain size distribution of the cerium oxide-doped indium oxide ceramic target prepared in Example 2 is uniform, and the average grain size is 3.69 μm, which effectively improves the grain size control problem of the ICO target.

[0094] Example 3

[0095] In Example 3, the method for preparing an ICO sputtering target with fine and uniform grains includes:

[0096] S1. Weigh the raw material powder and the dispersant according to the set ratio and mix them evenly to obtain a raw material slurry; wherein the mass of cerium oxide powder in the raw material powder accounts for 2%, the mass of indium oxide powder accounts for 98%, the mass ratio of dispersant ammonium polyacrylate to raw material powder is 1.5:100, and pure water accounts for 60% of the total mass of the raw material slurry;

[0097] S2, ball milling: put the raw material slurry into a ball milling jar with zirconia grinding balls, and place it on a ball mill to start ball milling; the ball milling time is controlled at 6 hours, the speed of the ball mill is 280r / min, the mass ratio of zirconia grinding balls to slurry is controlled at 4:1, and the diameters of the selected grinding balls are 1mm, 3mm and 6mm, respectively, and the mass ratio is 1:1:1;

[0098] S3, sand milling: after the ball milling is completed, the slurry in the ball milling tank is taken out and transferred to a sand mill for sand milling. The sand milling time is controlled at 80 minutes. The speed of the sand mill is first operated at a low speed, then the speed is increased, and then it is operated at a high speed, and finally it is operated at a low speed until the end. The speed control is as follows: the speed of the low speed operation is set to 1800r / min, and the speed of the high speed operation is set to 2500r / min. The total operation time of the low speed sand milling is 15 minutes, and the operation time of the high speed sand milling is 65 minutes. During the sand milling, the temperature of the slurry is controlled to be maintained at 40°C. 10 minutes before the end of the sand milling treatment, polyvinyl alcohol is added to the slurry as a binder, and the content of the binder accounts for 1.5% of the mass of the powder.

[0099] S4, spray granulation: the raw material slurry obtained by sand grinding is placed in a beaker, and an appropriate amount of defoaming agent n-octanol is added thereto to eliminate bubbles in the slurry, so as to facilitate the subsequent acquisition of granulated powder with good fluidity and close to spherical shape; the slurry is then pumped into a granulator for spray granulation; wherein the temperature of the spray granulator is set to 250°C, and the centrifugal frequency of the atomizer is 45Hz;

[0100] S5. Compression molding: Weigh a certain mass of granulated powder and put it into a steel mold and gently vibrate the mold to make the powder more evenly distributed and compact in the mold, and use a hydraulic press for compression molding; the pressure of the hydraulic press is set to 50MP, and the pressure holding time is 4 minutes; after the pressure holding is completed, demold the target blank to obtain;

[0101] S6, cold isostatic pressing: put the target blank into a vacuum bag, put it into a vacuum packaging machine for vacuum treatment, and then put the packaged target blank into a cold isostatic press for cold isostatic pressing. The pressure of the cold isostatic press is set to 220MP, and the pressure holding time is 8 minutes to obtain a high-density target blank with uniform density.

[0102] S7, target sintering:

[0103] S701, slowly heating from room temperature to degreasing temperature for degreasing treatment; wherein the degreasing temperature is 700°C, the heating rate is 1.25°C / min, and the degreasing holding time is 200min;

[0104] S702, after the debinding stage is completed, continue heating from the debinding temperature and quickly raise the temperature to the first sintering temperature for the first sintering; wherein the first sintering temperature is 1580°C, the heating rate is 2.5°C / min, and the first sintering time is 20min;

[0105] S703, after the first sintering is completed, the temperature is rapidly lowered from the first sintering temperature to the second sintering temperature for the second sintering; wherein the second sintering temperature is 1540°C, which is 40°C lower than the first sintering temperature, the cooling rate is 3°C / min, and the second sintering time is 1800min;

[0106] S704, after the second sintering is completed, the temperature is slowly lowered from the second sintering temperature to the third sintering temperature for the third sintering; wherein the third sintering temperature is 1000°C, the cooling rate is controlled to be 1.5°C / min, and the third sintering time is 250min;

[0107] S705. After the third sintering, the temperature is lowered to 200°C at a cooling rate of 4°C / min; and then naturally lowered to room temperature.

[0108] The grain size distribution of the cerium oxide-doped indium oxide ceramic target prepared in Example 3 is uniform, and the average grain size is 4.01 μm, which effectively improves the grain size control problem of the ICO target.

[0109] Comparative Example 1

[0110] In Comparative Example 1, the preparation method of the ICO sputtering target includes:

[0111] S1. Weigh the raw material powder and the dispersant according to the set ratio and mix them evenly to obtain a raw material slurry; wherein the mass of cerium oxide powder in the raw material powder accounts for 2.5%, the mass of indium oxide powder accounts for 97.5%, the mass ratio of dispersant ammonium polyacrylate to raw material powder is 1:100, and pure water accounts for 60% of the total mass of the raw material slurry;

[0112] S2, ball milling treatment: the raw material slurry is placed in a ball milling jar with zirconia grinding balls, and the jar is placed on a ball mill to start ball milling; the ball milling time is controlled at 8 hours, the speed of the ball mill is 250r / min, the mass ratio of zirconia grinding balls to slurry is controlled at 2.5:1, and the diameters of the selected grinding balls are 1mm, 3mm and 6mm, respectively, and the mass ratio is 1:1:1;

[0113] S3, sand milling: after the ball milling is completed, the slurry in the ball milling tank is taken out and transferred to a sand mill for sand milling. The sand milling time is controlled at 60 minutes. The speed of the sand mill is first operated at a low speed, then the speed is increased, and then it is operated at a high speed, and finally it is operated at a low speed until the end. The speed control is as follows: the speed of the low speed operation is set to 1600r / min, and the speed of the high speed operation is set to 2300r / min; the total operation time of the low speed sand milling is 10 minutes, and the operation time of the high speed sand milling is 50 minutes; the temperature of the slurry is controlled to be maintained at 20°C during sand milling. 10 minutes before the end of the sand milling treatment, polyvinyl alcohol is added to the slurry as a binder, and the content of the binder accounts for 0.5% of the mass of the powder;

[0114] S4, spray granulation: the raw material slurry obtained by sand grinding is placed in a beaker, and an appropriate amount of defoaming agent n-octanol is added thereto to eliminate bubbles in the slurry, so as to facilitate the subsequent acquisition of granulated powder with good fluidity and close to spherical shape; the slurry is then pumped into a granulator for spray granulation; wherein the temperature of the spray granulator is set to 200°C, and the centrifugal frequency of the atomizer is 45Hz;

[0115] S5. Compression molding: Weigh a certain mass of granulated powder and put it into a steel mold and gently vibrate the mold to make the powder more evenly distributed and compact in the mold, and use a hydraulic press for compression molding; the pressure of the hydraulic press is set to 50MP, and the pressure holding time is 5min; after the pressure holding is completed, demold the target blank to obtain;

[0116] S6, cold isostatic pressing: put the target blank into a vacuum bag, put it into a vacuum packaging machine for vacuum treatment, and then put the packaged target blank into a cold isostatic press for cold isostatic pressing. The pressure of the cold isostatic press is set to 250MP, and the pressure holding time is 5min to obtain a high-density target blank with uniform density.

[0117] S7, target sintering:

[0118] Heating stage: the target is heated from room temperature to 1580°C at a heating rate of 3°C / min and kept warm for 1800 min;

[0119] Slow cooling stage: After the insulation is completed, the cooling rate is controlled to drop from 1580℃ to 200℃ at 2℃ / min;

[0120] Afterwards, the heating was stopped and the mixture was cooled to room temperature to obtain a cerium oxide-doped indium oxide sputtering target.

[0121] Figure 3 This is the organizational morphology of the ICO sputtering target in Comparative Example 1. The grain size distribution of the cerium oxide-doped indium oxide ceramic target prepared in Comparative Example 1 is uneven, and abnormally grown coarse grains appear. The average grain size reaches 12.26 μm.

[0122] The method for preparing an ICO sputtering target with fine and uniform grains disclosed in an embodiment of the present invention can obtain an ICO sputtering target with fine and uniform grains. The target has fine grains, an average grain size of 2.62 μm, high density, and a relative density of 98.07%, which is conducive to the preparation of high-performance ICO films and has good application prospects in the field of ICO sputtering target preparation.

[0123] The technical solutions disclosed in the embodiments of the present invention and the technical details disclosed in the embodiments are merely illustrative of the inventive concept of the present invention and do not constitute a limitation on the technical solutions of the embodiments of the present invention. Any conventional changes, replacements or combinations of the technical details disclosed in the embodiments of the present invention have the same inventive concept as the present invention and are within the protection scope of the claims of the present invention.

Claims

1. A method for preparing an ICO sputtering target with fine and uniform grains, characterized in that: Includes steps: S1. Mixing raw material powder, dispersant and water to prepare raw material slurry; wherein the raw material powder consists of indium oxide powder and cerium oxide powder; S2, the raw material slurry is subjected to ball milling treatment; S3, the raw material slurry after ball milling is subjected to sand milling; S4, spray granulating the raw material slurry after sand milling to obtain raw material granulated powder; S5, the raw material granulated powder is molded to obtain a target blank; S6, the target material blank is subjected to cold isostatic pressing to obtain a high-density target material blank; S7, sintering the high-density target blank to obtain an ICO target with fine and uniform grains; Among them, the sintering of high-density target blanks includes: S701, slowly heating from room temperature to degreasing temperature for degreasing treatment; wherein the degreasing temperature is 500-750°C, the heating rate is 0.5-2°C / min, and the degreasing holding time is 180-300min; S702, after the debinding stage is completed, continue heating from the debinding temperature and quickly raise the temperature to the first sintering temperature for the first sintering; wherein the first sintering temperature is 1450-1600° C., the heating rate is 2-4° C. / min, and the first sintering time is 20-180 min; S703, after the first sintering is completed, the temperature is rapidly lowered from the first sintering temperature to the second sintering temperature for a second sintering; wherein the second sintering temperature is 10-100°C lower than the first sintering temperature, the cooling rate is 2-5°C / min, and the second sintering time is 1200-1800min; S704, after the second sintering is completed, the temperature is slowly lowered from the second sintering temperature to the third sintering temperature for the third sintering; wherein the third sintering temperature is 800-1000°C, the cooling rate is controlled to be 0.5-2°C / min, and the third sintering time is 180-360min; S705. After the third sintering is completed, the temperature is lowered to 200°C at a cooling rate of 2-5°C / min; and then the temperature is naturally lowered to room temperature.

2. The method for preparing an ICO sputtering target with fine and uniform grains according to claim 1, characterized in that: In step S1, the mass ratio of indium oxide powder to cerium oxide powder is 90-99.5:0.5-10, the mass ratio of dispersant to raw material powder is 0.5-2:100, and the mass content of water in the raw material slurry is 50-70%.

3. The method for preparing an ICO sputtering target with fine and uniform grains according to claim 1, characterized in that: In step S2, the ball milling treatment is carried out on a ball mill, the ball milling time is controlled at 6 to 12 hours, the rotation speed of the ball mill is 250 to 320 r / min, the mass ratio of zirconia grinding balls to raw material slurry is controlled at 2.5 to 4:1, the grinding ball diameters are selected to be 1 mm, 3 mm and 6 mm, and the mass ratio of the grinding balls is 1:1:1 respectively.

4. The method for preparing an ICO sputtering target with fine and uniform grains according to claim 1, characterized in that: In step S3, the sanding method includes: Transfer the uniformly mixed slurry to a sand mill for sand grinding; The sand mill runs at low speed for low-speed sand grinding, with a speed of 1500-2000r / min; Then the sand mill runs at high speed for high-speed sand grinding, with a speed of 2000-2500r / min; Finally, the sand mill runs at a low speed for low-speed sand grinding, with a speed of 1500-2000r / min; The total time of high-speed sand milling is controlled at 30 to 75 minutes, the total time of low-speed sand milling is controlled at 10 to 15 minutes, the temperature of the slurry is controlled to be maintained at 20 to 40°C during sand milling, and polyvinyl alcohol is added to the slurry as a binder between 5 and 15 minutes before the end of the sand milling process, and the mass ratio of the binder to the raw material powder is 0.2 to 2:

100.

5. The method for preparing an ICO sputtering target with fine and uniform grains according to claim 1, characterized in that: In step S4, spray granulation is performed on a spray granulator, the temperature of the spray granulator is 190-250° C., and the centrifugal frequency is 30-45 Hz.

6. The method for preparing an ICO sputtering target with fine and uniform grains according to claim 1, characterized in that: In step S5, the compression molding is performed in a hydraulic press, the pressure of the hydraulic press is set to 40-70 MPa, and the holding time is 3-8 min.

7. The method for preparing an ICO sputtering target with fine and uniform grains according to claim 1, characterized in that: In step S6, cold isostatic pressing is performed in a cold isostatic press, the pressure of the cold isostatic press is set to 190-250 MPa, and the holding time is 3-8 min.

8. An ICO sputtering target with fine and uniform grains, characterized in that: The ICO sputtering target material with fine and uniform grains is obtained by the preparation method of any one of claims 1 to 7, wherein the relative density of the ICO sputtering target material with fine and uniform grains reaches 98.07% and the average grain size is 2.62 μm.

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