Large-size lead-rich pzt target material preparation method and application

Abstract

The application belongs to the technical field of target materials, and particularly relates to a preparation method and application of a large-size lead-rich PZT target material; the preparation method of the large-size lead-rich PZT target material comprises the steps of target material raw material weighing and pretreatment, PZT granulated powder forming, target material sintering pretreatment, and main and auxiliary sintering; on the one hand, by using a PZT blank gasket with a peripheral size larger than that of the PZT blank, internal stress generated by the difference in expansion coefficients of the kiln furniture is reduced, sticking of the kiln furniture is avoided, the cracking rate of the target material is reduced, and the yield is improved; on the other hand, by using main and auxiliary collaborative sintering, the liquid phase viscosity is reduced, the internal pores are filled, and the target material density and component uniformity are improved under the condition of minimizing the volatilization amount of lead oxide, so that the preparation process of the large-size lead-rich PZT target material has high yield and excellent performance, and the large-size lead-rich PZT target material can be efficiently prepared, thereby solving the technical problem that the large-size lead-rich PZT target material is difficult to be efficiently prepared in the prior art.

Description

Technical Field

[0001] This application belongs to the field of target technology, and in particular relates to a method for preparing and applying large-size lead-rich PZT targets. Background Technology

[0002] Lead zirconate titanate (PZT) targets are key targets used in the fabrication of semiconductors, microelectronics, or sensor devices. When using PZT targets for magnetron sputtering to deposit thin films on wafer surfaces, lead-rich PZT targets are typically used to obtain high-quality films. Currently, the mainstream wafer size has reached 12 inches (300 mm), and with the development of semiconductor technology, the industry is constantly pushing towards larger wafer sizes to improve production efficiency and reduce the cost per chip, which places higher demands on the size of PZT targets.

[0003] Currently, PZT targets are mainly prepared using sintering processes. However, during the preparation of lead-rich PZT targets, issues such as uneven composition and low density arise. The large size of large-sized lead-rich PZT targets exacerbates these problems, posing a challenge to their preparation. Furthermore, the sintering process of large-sized lead-rich PZT targets is prone to deformation and cracking, leading to a decrease in yield. Therefore, it is currently difficult to produce large-sized lead-rich PZT targets efficiently. It is necessary to develop a new generation of large-sized lead-rich PZT target preparation processes to improve both density and yield, thereby enhancing the production efficiency of large-sized lead-rich PZT targets. Summary of the Invention

[0004] In view of this, this application provides a method for preparing large-size lead-rich PZT targets and its application, which solves the technical problem that it is difficult to efficiently prepare large-size lead-rich PZT targets in existing processes.

[0005] The first aspect of this application provides a method for preparing a large-size lead-rich PZT target, the method comprising the following steps: The steps for weighing target material raw materials are as follows: according to the chemical formula Pb x Zr y Ti z The stoichiometric ratio shown in O3 is used to weigh the corresponding lead source powder, zirconium source powder and titanium source powder as target material raw materials. In the chemical formula, x≥1, y+z=1. The steps of target material pretreatment are as follows: the weighed target material is ball-milled and mixed, sealed and pre-sintered, powdered and granulated in sequence to obtain PZT granulated powder. The steps for forming PZT granulated powder are as follows: PZT granulated powder is pressed into PZT blanks and PZT blank spacers respectively, and the outer dimensions of the PZT blank spacers are larger than the outer dimensions of the PZT blanks. The steps of the target material pre-sintering treatment are as follows: PZT granulated powder is laid in sequence in the kiln furniture, PZT green body pads are placed, PZT green body is placed, PZT granulated powder is used to bury the PZT green body, a support structure is set up and the kiln furniture lid is covered and sealed. The steps of main and auxiliary sintering of target material are as follows: place the kiln furniture in the sintering furnace, hold at 950~1200℃ for 1~6h for main sintering, and hold at 30~50℃ higher than the main sintering temperature for 5~30min for auxiliary sintering to obtain large-size lead-rich PZT target material.

[0006] Preferably, after the main and auxiliary sintering steps of the target material, a post-processing step is also included: processing and bonding the large-size lead-rich PZT target material.

[0007] Preferably, in the step of weighing the target material, the lead source powder is selected from one or more of lead tetroxide powder, lead monoxide powder, and lead dioxide powder; The zirconium source powder is selected from zirconium dioxide powder; The titanium source powder is selected from titanium dioxide powder.

[0008] Preferably, in the step of weighing the target material, x = 1~1.35, y = 0.05~0.95, and z = 0.05~0.95.

[0009] Preferably, in the target material pretreatment step, the ball milling and mixing process includes: loading the target material into the ball mill jar of the ball mill and adding ball milling media according to the ratio of ball:material = (1~3):1, and starting the ball mill for a ball milling time of 2~8 hours.

[0010] Preferably, in the target material pretreatment step, the sealing pre-sintering process includes: sealing and pre-sintering the mixed powder obtained by ball milling and mixing at 800~1000℃ for 1~5 hours.

[0011] Preferably, in the target material pretreatment step, the powder preparation process includes: sequentially crushing, ball milling, and sieving the pre-sintered powder obtained by sealed pre-sintering to obtain pre-sintered powder with a particle size of 0.5~3μm.

[0012] Preferably, in the target material pretreatment step, the granulation process includes: mixing the pre-calcined powder and binder solution evenly and then performing manual granulation or spray granulation to obtain PZT granulated powder with a particle size of 30~70μm.

[0013] Preferably, in the step of forming the PZT granulated powder, the PZT preform spacer is a circular spacer with a diameter of 460~500mm and a thickness of 1~3mm; the PZT preform is a circular preform with a diameter of 420~450mm and a thickness of 10~15mm.

[0014] Preferably, in the step of forming the PZT granulated powder, the pressing pressure is 500~1500t and the time is 1~3min.

[0015] Preferably, in the pretreatment step of the target material sintering, the kiln furniture is selected from one of a sealed movable crucible and a sealed crucible; the kiln furniture material is selected from one or more of alumina, zirconium oxide, mullite, and cordierite; and the support structure is selected from one or more of alumina strips, zirconium oxide strips, mullite strips, and cordierite strips.

[0016] Preferably, in the pretreatment step of the target material sintering, the thickness of the PZT granulated powder is 0.5~2mm.

[0017] Preferably, in the main and auxiliary sintering steps of the target material, the heating rate from the main sintering to the auxiliary sintering is 2~8℃ / min.

[0018] Preferably, the target material processing process includes: parallelism processing, outer circle processing, and flatness processing of the target material; The target bonding process includes: melting 4N metallic indium at 180-260℃, coating it onto the bonding surface of a large-size lead-rich PZT target that has undergone planar processing, and bonding it with a backing plate.

[0019] The second aspect of this application provides the application of large-size lead-rich PZT targets prepared by the preparation method described in the first aspect in the preparation of microelectronic devices, sensor devices or semiconductor devices.

[0020] The method for preparing large-size lead-rich PZT sputtering targets provided in this application has at least the following beneficial effects: 1. The method for preparing large-size lead-rich PZT targets provided in this application uses PZT blank spacers with outer dimensions larger than the PZT blanks during the pre-sintering process. This reduces internal stress caused by the difference in expansion coefficients between the PZT blanks and the kiln furniture, and also avoids adhesion to the kiln furniture. This effectively reduces the cracking rate of large-size lead-rich PZT targets and improves the yield of the targets.

[0021] 2. The method for preparing large-size lead-rich PZT target material provided in this application adds a brief secondary auxiliary sintering after the main sintering temperature during the sintering process. This can reduce the liquid phase viscosity, fill the internal pores, and improve the density and composition uniformity of the target material while minimizing the amount of lead oxide volatilization. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the specific embodiments of this application or the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0023] Figure 1 SEM image of a large-size lead-rich PZT target obtained by a preparation method provided in Example 1 of this application; Figure 2 The XRD pattern of the large-size lead-rich PZT target obtained by the preparation method provided in Example 1 of this application; Detailed Implementation

[0024] This application provides a method for preparing large-size lead-rich PZT targets and its application, which solves the technical problem that it is difficult to efficiently prepare large-size lead-rich PZT targets in existing processes.

[0025] The technical solutions of this application will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0026] Example 1

[0027] This embodiment provides a method for preparing large-size lead-rich PZT targets, including the steps of weighing target raw materials, pretreatment of target raw materials, forming PZT granulation powder, pretreatment of target sintering, main and auxiliary sintering of target, and post-treatment.

[0028] The steps for weighing the target material include: According to the chemical formula Pb 1.25 Zr 0.5 Ti 0.5 The stoichiometric ratio shown in O3 is used to weigh out the corresponding lead tetroxide (Pb3O4) powder with a purity of 99%, zirconium dioxide (ZrO2) powder with a purity of 99%, and titanium dioxide (TiO2) powder with a purity of 99% as target materials.

[0029] The steps of target material pretreatment include: Weigh the target material and load it into the ball mill jar of the ball mill. Add zirconia ceramic balls at a ratio of ball:material = 1.5:1. Start the ball mill with the parameters set at 31.7 Hz and the ball milling time set at 5 h. After the ball milling and mixing are completed, sieve out the powder to obtain the mixed powder. The mixed powder was loaded into an alumina crucible, the crucible lid was closed, and the crucible gaps were filled with zirconium oxide slurry and dried. After drying, the alumina crucible was placed in a muffle furnace for sealed pre-sintering at a sintering temperature of 850℃ and a holding time of 3h to obtain pre-sintered powder. After the pre-calcined powder is naturally cooled to room temperature, it is taken out from the alumina crucible, crushed, loaded into a ball mill jar for ball milling, and sieved to obtain pre-calcined powder with a particle size of about 1 μm. Weigh the pre-calcined powder and the binder polyvinyl alcohol (PVA) at a mass ratio of 95:5. Dissolve the weighed binder in an appropriate amount of water to make a binder solution. Stir the solution evenly with the pre-calcined powder and then spray granulate. The powder with a particle size of about 45 μm after granulation is used as PZT granulation powder.

[0030] The steps involved in forming PZT granulated powder include: A portion of the PZT granulated powder was added into the 480mm diameter press cavity and leveled. The hydraulic pressing pressure was set to 700t, and the holding time was 1min. The resulting product had a diameter of D480. 2mm PZT blank gasket; A portion of the PZT granulated powder was added into the 440mm diameter press cavity and leveled. The hydraulic pressing pressure was set to 700t, and the holding time was 2min. The resulting product had a diameter of D440. 11mm PZT blank; The steps for pretreatment of the target material before sintering include: Transfer the PZT green blank spacer to the kiln furniture alumina sagger with a 1mm thick layer of PZT granulated powder, then transfer the PZT green blank onto the green blank spacer to form a stack, and take a small amount of PZT granulated powder and spread it evenly on the PZT green blank to completely bury the green blank in the powder; then place alumina strips around it for support, and cover the kiln furniture lid to seal it.

[0031] The steps of target sintering include: The kiln furniture was placed in the sintering furnace, and the main sintering temperature was set to 1200℃ with a holding time of 6 hours. After the main sintering was completed, the temperature was increased to 1250℃ at a rate of 5℃ / min and held for 10 minutes for auxiliary sintering, resulting in large-size lead-rich PZT targets. The scanning electron microscopy (SEM) image of the large-size lead-rich PZT targets is shown below. Figure 1 As shown, the X-ray diffraction (XRD) pattern is as follows. Figure 2 As shown.

[0032] Post-processing steps include: After the large-size lead-rich PZT target material is taken out, liquid wax is poured onto the surface of the target blank to fill the uneven gaps on the surface of the target blank, and then it is scraped smooth. The target blank is then placed on the processing equipment for planar processing and outer diameter processing. After processing, the sputtering surface is finely ground. Place the backplate and the processed target blank on a heating table. Place 500g of indium ingot with a purity of 99.99% on the backplate. Raise the temperature of the heating table to 210℃ and wait for the indium ingot to completely melt into a liquid state. Take a portion of the indium liquid and apply it to the bonding surface of the target blank using ultrasonic waves. After the coating is completed, attach the bonding surface to the backplate. After adjusting the center position, start cooling. After the indium liquid solidifies, remove the excess indium ingot to complete the target bonding. Then, clean the target material with anhydrous ethanol and perform subsequent analysis or product packaging as required.

[0033] Example 2

[0034] To explore the performance of another lead-rich PZT target formulation, this embodiment provides a method for preparing large-size lead-rich PZT targets, including the steps of weighing target raw materials, pretreatment of target raw materials, PZT granulation powder forming, pretreatment of target before sintering, main and auxiliary sintering of target, and post-treatment.

[0035] The steps for weighing the target material include: According to the chemical formula Pb 1.3 Zr 0.3 Ti 0.7 The stoichiometric ratio shown in O3 is used to weigh out the corresponding lead tetroxide (Pb3O4) powder with a purity of 99%, zirconium dioxide (ZrO2) powder with a purity of 99%, and titanium dioxide (TiO2) powder with a purity of 99% as target materials.

[0036] The steps of target material pretreatment include: Weigh the target material and load it into the ball mill jar of the ball mill. Add zirconia ceramic balls at a ratio of ball:material = 1.5:1. Start the ball mill with the parameters set at 31.7 Hz and the ball milling time set at 5 h. After the ball milling and mixing are completed, sieve out the powder to obtain the mixed powder. The mixed powder was loaded into an alumina crucible, the crucible lid was closed, and the crucible gaps were filled with zirconium oxide slurry and dried. After drying, the alumina crucible was placed in a muffle furnace for sealed pre-sintering at a sintering temperature of 850℃ and a holding time of 3h to obtain pre-sintered powder. After the pre-calcined powder is naturally cooled to room temperature, it is taken out from the alumina crucible, crushed, loaded into a ball mill jar for ball milling, and sieved to obtain pre-calcined powder with a particle size of about 1 μm. Weigh the pre-calcined powder and the binder polyvinyl alcohol (PVA) at a mass ratio of 95:5. Dissolve the weighed binder in an appropriate amount of water to make a binder solution. Stir the solution evenly with the pre-calcined powder and then spray granulate. The powder with a particle size of about 45 μm after granulation is used as PZT granulation powder.

[0037] The steps involved in forming PZT granulated powder include: A portion of the PZT granulated powder was added into the 480mm diameter press cavity and leveled. The hydraulic pressing pressure was set to 700t, and the holding time was 1min. The resulting product had a diameter of D480. 2mm PZT blank gasket; A portion of the PZT granulated powder was added into the 440mm diameter press cavity and leveled. The hydraulic pressing pressure was set to 700t, and the holding time was 2min. The resulting product had a diameter of D440. 11mm PZT blank; The steps for pretreatment of the target material before sintering include: Transfer the PZT green blank spacer to the kiln furniture alumina sagger with a 1mm thick layer of PZT granulated powder, then transfer the PZT green blank onto the green blank spacer to form a stack, and take a small amount of PZT granulated powder and spread it evenly on the PZT green blank to completely bury the green blank in the powder; then place alumina strips around it for support, and cover the kiln furniture lid to seal it.

[0038] The steps of target sintering include: The kiln furniture was placed in the sintering furnace, and the main sintering temperature was set to 1200℃ with a holding time of 6 hours. After the main sintering was completed, the temperature was increased to 1250℃ at a rate of 5℃ / min and held for 20 minutes for auxiliary sintering to obtain large-size lead-rich PZT target materials.

[0039] Post-processing steps include: After the large-size lead-rich PZT target material is taken out, liquid wax is poured onto the surface of the target blank to fill the uneven gaps on the surface of the target blank, and then it is scraped smooth. The target blank is then placed on the processing equipment for planar processing and outer diameter processing. After processing, the sputtering surface is finely ground. Place the backplate and the processed target blank on a heating table. Place 500g of indium ingot with a purity of 99.99% on the backplate. Raise the temperature of the heating table to 210℃ and wait for the indium ingot to completely melt into a liquid state. Take a portion of the indium liquid and apply it to the bonding surface of the target blank using ultrasonic waves. After the coating is completed, attach the bonding surface to the backplate. After adjusting the center position, start cooling. After the indium liquid solidifies, remove the excess indium ingot to complete the target bonding. Then, clean the target material with anhydrous ethanol and perform subsequent analysis or product packaging as required.

[0040] Comparative Example 1

[0041] To investigate the influence of the main and auxiliary sintering process on the performance of large-size lead-rich PZT targets, this comparative example provides a method for preparing large-size lead-rich PZT targets, including the steps of weighing target raw materials, pretreatment of target raw materials, PZT granulation powder forming, pretreatment of target before sintering, main sintering of target, and post-treatment.

[0042] The steps for weighing the target material include: According to the chemical formula Pb 1.25 Zr 0.5 Ti 0.5 The stoichiometric ratio shown in O3 is used to weigh out the corresponding lead tetroxide (Pb3O4) powder with a purity of 99%, zirconium dioxide (ZrO2) powder with a purity of 99%, and titanium dioxide (TiO2) powder with a purity of 99% as target materials.

[0043] The steps of target material pretreatment include: Weigh the target material and load it into the ball mill jar of the ball mill. Add zirconia ceramic balls at a ratio of ball:material = 1.5:1. Start the ball mill with the parameters set at 31.7 Hz and the ball milling time set at 5 h. After the ball milling and mixing are completed, sieve out the powder to obtain the mixed powder. The mixed powder was loaded into an alumina crucible, the crucible lid was closed, and the crucible gaps were filled with zirconium oxide slurry and dried. After drying, the alumina crucible was placed in a muffle furnace for sealed pre-sintering at a sintering temperature of 850℃ and a holding time of 3h to obtain pre-sintered powder. After the pre-calcined powder is naturally cooled to room temperature, it is taken out from the alumina crucible, crushed, loaded into a ball mill jar for ball milling, and sieved to obtain pre-calcined powder with a particle size of about 1 μm. Weigh the pre-calcined powder and the binder polyvinyl alcohol (PVA) at a mass ratio of 95:5. Dissolve the weighed binder in an appropriate amount of water to make a binder solution. Stir the solution evenly with the pre-calcined powder and then spray granulate. The powder with a particle size of about 45 μm after granulation is used as PZT granulation powder.

[0044] The steps involved in forming PZT granulated powder include: A portion of the PZT granulated powder was added into the 480mm diameter press cavity and leveled. The hydraulic pressing pressure was set to 700t, and the holding time was 1min. The resulting product had a diameter of D480. 2mm PZT blank gasket; A portion of the PZT granulated powder was added into the 440mm diameter press cavity and leveled. The hydraulic pressing pressure was set to 700t, and the holding time was 2min. The resulting product had a diameter of D440. 11mm PZT blank; The steps for pretreatment of the target material before sintering include: Transfer the PZT green blank spacer to the kiln furniture alumina sagger with a 1mm thick layer of PZT granulated powder, then transfer the PZT green blank onto the green blank spacer to form a stack, and take a small amount of PZT granulated powder and spread it evenly on the PZT green blank to completely bury the green blank in the powder; then place alumina strips around it for support, and cover the kiln furniture lid to seal it.

[0045] The main sintering steps for the target material include: The kiln furniture was placed in the sintering furnace, the main sintering temperature was set to 1200℃, and the holding time was 6h, to obtain large-size lead-rich PZT target materials.

[0046] Post-processing steps include: After the large-size lead-rich PZT target material is taken out, liquid wax is poured onto the surface of the target blank to fill the uneven gaps on the surface of the target blank, and then it is scraped smooth. The target blank is then placed on the processing equipment for planar processing and outer diameter processing. After processing, the sputtering surface is finely ground. Place the backplate and the processed target blank on a heating table. Place 500g of indium ingot with a purity of 99.99% on the backplate. Raise the temperature of the heating table to 210℃ and wait for the indium ingot to completely melt into a liquid state. Take a portion of the indium liquid and apply it to the bonding surface of the target blank using ultrasonic waves. After the coating is completed, attach the bonding surface to the backplate. After adjusting the center position, start cooling. After the indium liquid solidifies, remove the excess indium ingot to complete the target bonding. Then, clean the target material with anhydrous ethanol and perform subsequent analysis or product packaging as required.

[0047] Comparative Example 2

[0048] To investigate the effect of temperature during the main-auxiliary sintering process on the performance of large-size lead-rich PZT targets, this comparative example provides a method for preparing large-size lead-rich PZT targets, including the steps of weighing target raw materials, pretreatment of target raw materials, PZT granulation powder forming, pretreatment of target before sintering, main-auxiliary sintering of the target, and post-treatment.

[0049] The steps for weighing the target material include: According to the chemical formula Pb 1.25 Zr 0.5 Ti 0.5 The stoichiometric ratio shown in O3 is used to weigh out the corresponding lead tetroxide (Pb3O4) powder with a purity of 99%, zirconium dioxide (ZrO2) powder with a purity of 99%, and titanium dioxide (TiO2) powder with a purity of 99% as target materials.

[0050] The steps of target material pretreatment include: Weigh the target material and load it into the ball mill jar of the ball mill. Add zirconia ceramic balls at a ratio of ball:material = 1.5:1. Start the ball mill with the parameters set at 31.7 Hz and the ball milling time set at 5 h. After the ball milling and mixing are completed, sieve out the powder to obtain the mixed powder. The mixed powder was loaded into an alumina crucible, the crucible lid was closed, and the crucible gaps were filled with zirconium oxide slurry and dried. After drying, the alumina crucible was placed in a muffle furnace for sealed pre-sintering at a sintering temperature of 850℃ and a holding time of 3h to obtain pre-sintered powder. After the pre-calcined powder is naturally cooled to room temperature, it is taken out from the alumina crucible, crushed, loaded into a ball mill jar for ball milling, and sieved to obtain pre-calcined powder with a particle size of about 1 μm. Weigh the pre-calcined powder and the binder polyvinyl alcohol (PVA) at a mass ratio of 95:5. Dissolve the weighed binder in an appropriate amount of water to make a binder solution. Stir the solution evenly with the pre-calcined powder and then spray granulate. The powder with a particle size of about 45 μm after granulation is used as PZT granulation powder.

[0051] The steps involved in forming PZT granulated powder include: A portion of the PZT granulated powder was added into the 480mm diameter press cavity and leveled. The hydraulic pressing pressure was set to 700t, and the holding time was 1min. The resulting product had a diameter of D480. 2mm PZT blank gasket; A portion of the PZT granulated powder was added into the 440mm diameter press cavity and leveled. The hydraulic pressing pressure was set to 700t, and the holding time was 2min. The resulting product had a diameter of D440. 11mm PZT blank; The steps for pretreatment of the target material before sintering include: Transfer the PZT green blank spacer to the kiln furniture alumina sagger with a 1mm thick layer of PZT granulated powder, then transfer the PZT green blank onto the green blank spacer to form a stack, and take a small amount of PZT granulated powder and spread it evenly on the PZT green blank to completely bury the green blank in the powder; then place alumina strips around it for support, and cover the kiln furniture lid to seal it.

[0052] The steps of target sintering include: The kiln furniture was placed in the sintering furnace, and the main sintering temperature was set to 1200℃ with a holding time of 6 hours. After the main sintering was completed, the temperature was increased to 1280℃ at a rate of 5℃ / min and held for 10 minutes for auxiliary sintering to obtain large-size lead-rich PZT target materials.

[0053] Post-processing steps include: After the large-size lead-rich PZT target material is taken out, liquid wax is poured onto the surface of the target blank to fill the uneven gaps on the surface of the target blank, and then it is scraped smooth. The target blank is then placed on the processing equipment for planar processing and outer diameter processing. After processing, the sputtering surface is finely ground. Place the backplate and the processed target blank on a heating table. Place 500g of indium ingot with a purity of 99.99% on the backplate. Raise the temperature of the heating table to 210℃ and wait for the indium ingot to completely melt into a liquid state. Take a portion of the indium liquid and apply it to the bonding surface of the target blank using ultrasonic waves. After the coating is completed, attach the bonding surface to the backplate. After adjusting the center position, start cooling. After the indium liquid solidifies, remove the excess indium ingot to complete the target bonding. Then, clean the target material with anhydrous ethanol and perform subsequent analysis or product packaging as required.

[0054] Comparative Example 3

[0055] To investigate the effect of the time of the main and auxiliary sintering process on the performance of large-size lead-rich PZT targets, this comparative example provides a method for preparing large-size lead-rich PZT targets, including the steps of weighing target raw materials, pretreatment of target raw materials, PZT granulation powder forming, pretreatment of target before sintering, main and auxiliary sintering of the target, and post-treatment.

[0056] The steps for weighing the target material include: According to the chemical formula Pb 1.25 Zr 0.5 Ti 0.5 The stoichiometric ratio shown in O3 is used to weigh out the corresponding lead tetroxide (Pb3O4) powder with a purity of 99%, zirconium dioxide (ZrO2) powder with a purity of 99%, and titanium dioxide (TiO2) powder with a purity of 99% as target materials.

[0057] The steps of target material pretreatment include: Weigh the target material and load it into the ball mill jar of the ball mill. Add zirconia ceramic balls at a ratio of ball:material = 1.5:1. Start the ball mill with the parameters set at 31.7 Hz and the ball milling time set at 5 h. After the ball milling and mixing are completed, sieve out the powder to obtain the mixed powder. The mixed powder was loaded into an alumina crucible, the crucible lid was closed, and the crucible gaps were filled with zirconium oxide slurry and dried. After drying, the alumina crucible was placed in a muffle furnace for sealed pre-sintering at a sintering temperature of 850℃ and a holding time of 3h to obtain pre-sintered powder. After the pre-calcined powder is naturally cooled to room temperature, it is taken out from the alumina crucible, crushed, loaded into a ball mill jar for ball milling, and sieved to obtain pre-calcined powder with a particle size of about 1 μm. Weigh the pre-calcined powder and the binder polyvinyl alcohol (PVA) at a mass ratio of 95:5. Dissolve the weighed binder in an appropriate amount of water to make a binder solution. Stir the solution evenly with the pre-calcined powder and then spray granulate. The powder with a particle size of about 45 μm after granulation is used as PZT granulation powder.

[0058] The steps involved in forming PZT granulated powder include: A portion of the PZT granulated powder was added into the 480mm diameter press cavity and leveled. The hydraulic pressing pressure was set to 700t, and the holding time was 1min. The resulting product had a diameter of D480. 2mm PZT blank gasket; A portion of the PZT granulated powder was added into the 440mm diameter press cavity and leveled. The hydraulic pressing pressure was set to 700t, and the holding time was 2min. The resulting product had a diameter of D440. 11mm PZT blank; The steps for pretreatment of the target material before sintering include: Transfer the PZT green blank spacer to the kiln furniture alumina sagger with a 1mm thick layer of PZT granulated powder, then transfer the PZT green blank onto the green blank spacer to form a stack, and take a small amount of PZT granulated powder and spread it evenly on the PZT green blank to completely bury the green blank in the powder; then place alumina strips around it for support, and cover the kiln furniture lid to seal it.

[0059] The steps of target sintering include: The kiln furniture was placed in the sintering furnace, and the main sintering temperature was set to 1200℃ with a holding time of 6 hours. After the main sintering was completed, the temperature was increased to 1250℃ at a rate of 5℃ / min and held for 60 minutes for auxiliary sintering to obtain large-size lead-rich PZT target materials.

[0060] Post-processing steps include: After the large-size lead-rich PZT target material is taken out, liquid wax is poured onto the surface of the target blank to fill the uneven gaps on the surface of the target blank, and then it is scraped smooth. The target blank is then placed on the processing equipment for planar processing and outer diameter processing. After processing, the sputtering surface is finely ground. Place the backplate and the processed target blank on a heating table. Place 500g of indium ingot with a purity of 99.99% on the backplate. Raise the temperature of the heating table to 210℃ and wait for the indium ingot to completely melt into a liquid state. Take a portion of the indium liquid and apply it to the bonding surface of the target blank using ultrasonic waves. After the coating is completed, attach the bonding surface to the backplate. After adjusting the center position, start cooling. After the indium liquid solidifies, remove the excess indium ingot to complete the target bonding. Then, clean the target material with anhydrous ethanol and perform subsequent analysis or product packaging as required.

[0061] Comparative Example 4

[0062] To investigate the effect of using a gasket with an outer dimension larger than that of the PZT blank on the performance of large-size lead-rich PZT sputtering targets, this comparative example provides a method for preparing large-size lead-rich PZT sputtering targets, including the steps of weighing the target raw materials, pre-treatment of the target raw materials, forming PZT granulation powder, pre-treatment of the target before sintering, main and auxiliary sintering of the target, and post-treatment.

[0063] The steps for weighing the target material include: According to the chemical formula Pb 1.25 Zr 0.5 Ti 0.5 The stoichiometric ratio shown in O3 is used to weigh out the corresponding lead tetroxide (Pb3O4) powder with a purity of 99%, zirconium dioxide (ZrO2) powder with a purity of 99%, and titanium dioxide (TiO2) powder with a purity of 99% as target materials.

[0064] The steps of target material pretreatment include: Weigh the target material and load it into the ball mill jar of the ball mill. Add zirconia ceramic balls at a ratio of ball:material = 1.5:1. Start the ball mill with the parameters set at 31.7 Hz and the ball milling time set at 5 h. After the ball milling and mixing are completed, sieve out the powder to obtain the mixed powder. The mixed powder was loaded into an alumina crucible, the crucible lid was closed, and the crucible gaps were filled with zirconium oxide slurry and dried. After drying, the alumina crucible was placed in a muffle furnace for sealed pre-sintering at a sintering temperature of 850℃ and a holding time of 3h to obtain pre-sintered powder. After the pre-calcined powder is naturally cooled to room temperature, it is taken out from the alumina crucible, crushed, loaded into a ball mill jar for ball milling, and sieved to obtain pre-calcined powder with a particle size of about 1 μm. Weigh the pre-calcined powder and the binder polyvinyl alcohol (PVA) at a mass ratio of 95:5. Dissolve the weighed binder in an appropriate amount of water to make a binder solution. Stir the solution evenly with the pre-calcined powder and then spray granulate. The powder with a particle size of about 45 μm after granulation is used as PZT granulation powder.

[0065] The steps involved in forming PZT granulated powder include: A portion of the PZT granulated powder was added into the 440mm diameter press cavity and leveled. The hydraulic pressing pressure was set to 700t, and the holding time was 2min. The resulting product had a diameter of D440. 11mm PZT blank; The steps for pretreatment of the target material before sintering include: The PZT green body was transferred to an alumina sagger containing 1mm thick PZT granulated powder; then alumina strips were placed around it for support, and the kiln lid was sealed.

[0066] The steps of target sintering include: The kiln furniture was placed in the sintering furnace, and the main sintering temperature was set to 1200℃ with a holding time of 6 hours. After the main sintering was completed, the temperature was increased to 1250℃ at a rate of 5℃ / min and held for 10 minutes for auxiliary sintering to obtain large-size lead-rich PZT target materials.

[0067] Post-processing steps include: After the large-size lead-rich PZT target material is taken out, liquid wax is poured onto the surface of the target blank to fill the uneven gaps on the surface of the target blank, and then it is scraped smooth. The target blank is then placed on the processing equipment for planar processing and outer diameter processing. After processing, the sputtering surface is finely ground. Place the backplate and the processed target blank on a heating table. Place 500g of indium ingot with a purity of 99.99% on the backplate. Raise the temperature of the heating table to 210℃ and wait for the indium ingot to completely melt into a liquid state. Take a portion of the indium liquid and apply it to the bonding surface of the target blank using ultrasonic waves. After the coating is completed, attach the bonding surface to the backplate. After adjusting the center position, start cooling. After the indium liquid solidifies, remove the excess indium ingot to complete the target bonding. Then, clean the target material with anhydrous ethanol and perform subsequent analysis or product packaging as required.

[0068] Experimental Example 1

[0069] This experiment analyzes the performance of large-size lead-rich PZT targets prepared by the methods provided in Examples 1-2 and Comparative Examples 1-4. The analysis includes target density and cracking rate, and the results are shown in Table 1.

[0070] Table 1: Results of Target Material Density and Crack Rate

[0071] As shown in Table 1, the performance test results indicate that the large-size lead-rich PZT targets prepared by the methods provided in Examples 1 and 2 have higher target density and lower cracking rate, thus efficiently providing qualified large-size lead-rich PZT targets. However, the preparation method provided in Comparative Example 1, due to the absence of auxiliary sintering at a temperature 30-50°C above the main sintering temperature for 5-30 minutes during the sintering process, cannot temporarily reduce the viscosity of the liquid-phase lead oxide to increase its fluidity and fill the large-size lead-rich PZT targets. The porosity of the T-target material, particularly the inability to effectively eliminate some pores within the target, leads to a decrease in the density and compositional uniformity of the lead-rich PZT target, resulting in performance degradation. Comparative Examples 2 and 3, in their preparation methods, increased the temperature and time of the auxiliary sintering process. While increasing the auxiliary sintering temperature further reduces the viscosity of the liquid-phase lead oxide, increases its fluidity, and fills pores, the increased temperature also causes faster lead oxide volatilization, leading to a decrease in target density. Increasing the auxiliary sintering time, although allowing sufficient time for the liquid-phase lead oxide to flow and fill pores, also prolongs the lead oxide volatilization time, resulting in a decrease in target density. Furthermore, comparing Comparative Examples 2 and 3 shows that increasing the auxiliary sintering temperature results in a greater loss of lead than extending the auxiliary sintering time. Therefore, the preparation methods provided in Examples 1 and 2 of this application, by adding a brief secondary auxiliary sintering after the main sintering temperature, can reduce the liquid-phase viscosity, fill internal pores, and improve target density and compositional uniformity while minimizing lead oxide volatilization. The preparation method provided in Comparative Example 4, however, in its preparation method... In the pre-sintering process, the PZT green blank was not placed on the PZT green blank spacer to form a stack, which increased the cracking rate of large-size lead-rich PZT targets and reduced the target yield. However, the preparation methods provided in Examples 1 and 2 of this application use PZT green blank spacers with outer dimensions larger than the PZT green blank during the pre-sintering process to isolate the PZT green blank from the kiln furniture. This effectively alleviates the mismatch in expansion coefficients with the kiln furniture and avoids adhesion to the kiln furniture, thereby effectively reducing the cracking rate of large-size lead-rich PZT targets and improving the target yield.

[0072] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A method for preparing large-size lead-rich PZT target material, characterized in that, Includes the following steps: According to the chemical formula Pb x Zr y Ti z The stoichiometric ratio shown in O3 is used to weigh the corresponding lead source powder, zirconium source powder and titanium source powder as target material raw materials. In the chemical formula, x≥1, y+z=1. The steps of target material pretreatment are as follows: the weighed target material is ball-milled and mixed, sealed and pre-sintered, powdered and granulated in sequence to obtain PZT granulated powder. PZT granulated powder is pressed into PZT preforms and PZT preform spacers, respectively, and the outer dimensions of the PZT preform spacers are larger than the outer dimensions of the PZT preforms. PZT granulated powder is laid in sequence inside the kiln furniture, PZT green body pads are placed, PZT green body is placed, PZT granulated powder is used to bury the PZT green body, a support structure is set up and the kiln furniture lid is covered and sealed. The kiln furniture is placed in the sintering furnace, and the main sintering is carried out by holding at 950~1200℃ for 1~6h, and the auxiliary sintering is carried out by holding at 30~50℃ higher than the main sintering temperature for 5~30min, so as to obtain large-size lead-rich PZT target materials.

2. The method for preparing a large-size lead-rich PZT target according to claim 1, characterized in that, The lead source powder is selected from one or more of lead tetroxide powder, lead monoxide powder, and lead dioxide powder; The zirconium source powder is selected from zirconium dioxide powder; The titanium source powder is selected from titanium dioxide powder.

3. The method for preparing a large-size lead-rich PZT target according to claim 1, characterized in that, The values ​​are x = 1~1.35, y = 0.05~0.95, and z = 0.05~0.

95.

4. The method for preparing a large-size lead-rich PZT target according to claim 1, characterized in that, The sealed pre-sintering process includes: pre-sintering the mixed powder obtained by ball milling at 800~1000℃ for 1~5 hours.

5. The method for preparing a large-size lead-rich PZT target according to claim 1, characterized in that, The PZT blank gasket is a circular gasket with a diameter of 460~500mm, and the PZT blank is a circular blank with a diameter of 420~450mm.

6. The method for preparing a large-size lead-rich PZT target according to claim 1, characterized in that, The thickness of the PZT granulated powder is 0.5~2mm.

7. The method for preparing a large-size lead-rich PZT target according to claim 1, characterized in that, The kiln furniture is a sealed movable crucible or a sealed crucible made of one or more materials selected from alumina, zirconium oxide, mullite, and cordierite.

8. The method for preparing a large-size lead-rich PZT target according to claim 1, characterized in that, After assisted sintering, the process also includes: processing and bonding large-size lead-rich PZT targets.

9. A method for preparing a large-size lead-rich PZT target according to claim 8, characterized in that, The target material processing process includes: parallelism processing, outer circle processing, and flatness processing of the target material; The target bonding process includes: melting 4N metallic indium at 180-260℃, coating it onto the bonding surface of a large-size lead-rich PZT target that has undergone planar processing, and bonding it with a backing plate.

10. The application of the large-size lead-rich PZT target prepared by the preparation method according to any one of claims 1-9 in the preparation of microelectronic devices, sensor devices or semiconductor devices.

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