Preparation method of doped modified element zinc-based alloy sputtering target for semiconductor coating

Abstract

The application relates to a preparation method of a doped modified element zinc-based alloy sputtering target for semiconductor coating, and belongs to the field of metal sputtering target material preparation. The preparation method comprises the steps of material preparation, alloying smelting, centrifugal casting forming, synchronous water-cooling rapid solidification and surface machining. Through inert gas flow protection smelting, high-frequency induction heating, immersion feeding, rotating blade uniform stirring, pressure-filled centrifugal casting, synchronous water-cooling rapid solidification and surface machining, the target material with different specifications and sizes such as circular, rectangular and special-shaped can be prepared. The preparation method can solve the problem that it is difficult to dope the zinc-based sputtering target with active metal elements, obtain an alloy with a high content of doped elements, and prepare the target material with the advantages of uniform internal element distribution, small grain size, few volume defects and the like, effectively reduce the machining workload of the target material, and have the advantages of fast production efficiency, high product yield and low cost.

Description

TECHNICAL FIELD

[0001] The application relates to a preparation method of a doped modified element zinc-based alloy sputtering target for semiconductor coating, mainly applied to a semiconductor thin film material with special performance prepared by a magnetron sputtering, and belongs to the field of metal sputtering target material preparation. BACKGROUND

[0002] The sputtering target is a key raw material for preparing thin film materials in various chips, semiconductors and integrated circuits in the electronic industry field. With the reduction of the feature size of integrated circuits, the reduction of the line width and the increase of the connection layers, the quality requirement of the sputtering target is higher and higher. Data shows that there are very few enterprises capable of realizing large-scale production in the world; in recent years, enterprises specialized in the research and preparation of sputtering targets have emerged in China, and the independent research and production of high-purity metal targets have been realized, and the position in the world semiconductor target market is continuously rising. However, at present, the sputtering targets with special functions are mainly various alloys or element doped.

[0003] The doped alloy target can obtain the high conductivity, high signal transmission or wear resistance and corrosion resistance required by the semiconductor thin film by adding a small amount of modified elements into the target, so as to meet the diversified functional requirements of integrated circuits and semiconductors in complex environments. The ZnO thin film is an n-type wide band gap semiconductor with excellent electrical and optical properties, and is used as a special optoelectronic device material in the military field. The ZnO thin film is mainly deposited by DC reactive sputtering using high-purity zinc targets. Due to the diversified demand for optoelectronic thin film materials in national defense construction, different properties need to be realized in special environments, and the doping of modified elements in pure zinc targets is a research hotspot in the microelectronic industry. Doping other metal elements such as Al, Ni and Ga in high-zinc targets, the magnetron sputtering process forms ZnAl, ZnNi and ZnGa alloy thin films on the substrate surface, and oxide alloy thin films in an oxygen atmosphere. These oxide thin films often have other physical properties different from ZnO thin films due to the addition of doped elements, and achieve the modification purpose of thin film materials. For example, doping V elements in Zn to obtain Zn-V alloy targets, mainly using the special electrical properties of V elements, the conductivity of Zn-V-O thin film obtained by magnetron sputtering deposition is improved compared with single ZnO, the hardness and friction performance are obviously improved, and the influence of impurities on the performance of the thin film is reduced, which plays an important role in some complex application environments.

[0004] The photoelectric performance of the semiconductor surface depends on the composition uniformity and the organization quality of the magnetron sputtering deposited thin film material, and the quality of the thin film material is determined not only by the magnetron sputtering process, but also more importantly by the internal quality of the target material. Defects on the surface or inside of the target material will directly affect the quality of the deposited thin film in the production process, and the distribution of the doping elements and the grain size of the target material directly determine the quality of the sputtering deposition coating. Secondly, according to the phase diagram calculation, the modified elements V, Zr, Li, Ti, Al, Ga and Ni doped in Zn form a large number of intermetallic compounds due to the small solid solubility, and are not suitable for large-scale target material calendering preparation. Moreover, the modified elements are easily oxidized or have high vapor pressure, and it is difficult to achieve high content doping ratio by using the traditional casting form. During the slow solidification process of the alloy, the doping elements are easy to segregate and escape from the alloy. Therefore, the preparation method of the high content modified element doped in Zn to form a composition uniform alloy has been a blank. Moreover, the existing target material forming preparation method produces a large number of volume defects such as pores, inclusions, cracks, loose and oxide inclusions on the surface and inside of the target material, which is not suitable for the application development of the doped modified element sputtering target. SUMMARY

[0005] In order to solve the problems of difficult doping of modified elements in zinc-based target material and difficult processing, the application provides a preparation method of a doped modified element sputtering target for semiconductor coating. The preparation method can solve the problems of difficult doping of modified elements in zinc-based target material and difficult processing, obtain an alloy with a high content of doped elements, and prepare a target material with uniform internal element doping distribution, small grain size, few volume defects and the like. The preparation method effectively reduces the target material machining workload, has the advantages of fast production efficiency, high yield, low cost and the like, and all uses automatic equipment, which is beneficial to large-scale mass production.

[0006] The preparation method of the high content modified element doped Zn-based target material of the application solves the doping problem through tooling design and preparation process innovation, obtains high-quality target material forming, shortens the processing flow and greatly reduces the cost.

[0007] To achieve the above object, the application adopts the following technical scheme:

[0008] A preparation method of a doped modified element zinc-based alloy sputtering target for semiconductor coating, the method comprising the following steps:

[0009] (1) Preparing materials:

[0010] The sputtering target is composed of modified elements and Zn, the modified elements are selected from one or more of V, Zr, Li, Ti, Al, Ga and Ni, the content of the modified elements is 1.0-20.0wt.%, and the balance is Zn, and the total amount of the above components is 100wt.%; the components are weighed according to the mass fraction ratio in the alloy;

[0011] (2) Alloy smelting:

[0012] Put the Zn ingot into the crucible, wrap the modified elements with high-purity Zn foil and place them on the rotating blade of the stirring device, cover the crucible, and place it on the support frame of the heating coil of the centrifugal device; vacuumize the device to 10 -1 Pa; then introduce inert gas, maintain the flow rate of the gas, and the internal gas pressure of the crucible is 10 4 Pa; use high-frequency induction heating method, first smelt and refine the Zn ingot; then, maintain the heating power, immerse the rotating blade into the Zn melt, and keep it still for 5-10 min, start the blade rotation, and make the modified elements dissolve and disperse in the Zn melt to obtain an alloy melt with uniform element distribution;

[0013] (3) Centrifugal casting:

[0014] After the alloy melt of step (2) is stirred by rotation, automatically lift the rotating blade, close the gas outlet valve of the crucible, and open the centrifugal arm to perform rotational centrifugal casting;

[0015] (4) Synchronous water cooling and rapid solidification:

[0016] The inner cavity size of the centrifugal casting mold is 1.05-1.2 times the size of the target material, before starting the centrifugation, the mold is preheated by the embedded heating coil; after starting the centrifugation, the heating is stopped, the coil continuously introduces cooling water, and after the alloy melt fills the mold, it is cooled synchronously;

[0017] (5) Surface machining:

[0018] After the centrifugal casting is completed and the mold temperature drops to below 50°C, the alloy ingot doped with modified elements is taken out of the furnace; the alloy ingot doped with modified elements is machined on a numerical control machining center, and the machining size is machined to the size of the finished product.

[0019] In step (1), the purity of the modified elements V, Zr, Li, Ti, Al, Ga, and Ni raw materials is 99.999wt.%, and the purity of the Zn raw material is 99.995wt.%.

[0020] In step (2), the smelting crucible is made of high-strength magnesium oxide ceramic; the crucible is covered with the same material, fastened with threads, and the cover is provided with inlet and outlet gas pipelines for vacuumizing the interior of the crucible and introducing and discharging protective gas; the center of the cover is provided with a ceramic rod for lifting and rotating the blade.

[0021] In step (2), the smelting method is high-frequency induction heating, the heating power is 10-25 KW, the internal temperature of the crucible is 570-620°C, and the refining time is 2-5 min. The smelting environment is vacuumized to 10 -1Pa or below, then inert gas is introduced, the gas keeps flowing, the gas pressure inside the crucible is 10 4 Pa or below, then inert gas is introduced, the gas keeps flowing, the gas pressure inside the crucible is 10

[0022] In step (2), the secondary feeding mode is adopted, the modified elements are wrapped with high-purity Zn foil and placed on the rotating blade of the stirring device, after the high-purity Zn melt is refined, the rotating blade is immersed in the Zn melt, and the blade is rotated at a rotating speed of 500-1000 n / min for 5-10 min, so that the alloy melt with uniform distribution of elements is obtained.

[0023] In step (3), the casting form is rotary centrifugal casting, the centrifugal speed is set to 300-1000 n / min, the centrifugal time is 2-5 min, and the gas pressure of the smelting crucible during centrifugation is set to 15-25 Mpa.

[0024] In step (4), the graphite mold is selected as the centrifugal casting mold, and the inner cavity size of the graphite mold is 1.05-1.2 times the size of the target material.

[0025] In step (4), the graphite mold is selected as the centrifugal casting mold, and the inner cavity size of the graphite mold is 1.05-1.2 times the size of the target material.

[0026] In step (4), the graphite mold is selected as the centrifugal casting mold, and the inner cavity size of the graphite mold is 1.05-1.2 times the size of the target material.

[0027] In step (5), the surface machining is carried out by using a numerical control machining center to machine the surface of the ingot blank, and the machining size is to the size of the finished product, so that the modified element doped zinc-based alloy sputtering target material required is obtained.

[0028] The shape of the alloy sputtering target material is circular, rectangular and special-shaped, and the size specification is that the thickness is 0.3-20 mm, and the maximum size of the outer shape is 500 mm.

[0029] In the doped modified element zinc-based alloy sputtering target material, the total content of other impurities is less than 0.01 wt.%, the maximum grain size is less than 50 mu m, the average grain size is not more than 20 mu m, and the internal volume defect is not more than 0.2%.

[0030] The advantages of the present application are:

[0031] 1. The preparation method of the doped modified element sputtering target material solves the problem that the modified elements are difficult to be doped into the zinc-based sputtering target material, and a high content of doped element composition alloy is obtained.

[0032] 2, The target prepared by the preparation method of the doped modified element sputtering target has the advantages of uniform internal element doping distribution, small grain size, and few volume defects.

[0033] 3, The preparation method of the doped modified element sputtering target breaks through the complex process of traditional target casting and machining, effectively reduces the machining workload of the target, and has the advantages of fast production efficiency, high yield, and low cost.

[0034] 4, The preparation method disclosed by the application can obtain high-content doped elements and high-quality targets, and meet the urgent needs of sputter deposition of new semiconductor thin film materials.

[0035] 5, The application realizes full replacement of domestic products.

[0036] The preparation method includes inert gas flow protection smelting, high-frequency induction heating, immersion feeding, rotating blade uniform stirring, pressure-filled centrifugal casting, synchronous water cooling rapid solidification and surface machining. The tooling design includes integrated inflatable ceramic crucible, rotating stirring lifting blade paddle and water cooling combined mold. The preparation method can process and prepare targets of different specifications and sizes such as circular, rectangular and special-shaped targets. The preparation method can solve the problem of difficult doping of active metal elements in zinc-based sputtering targets, obtain high-content doped element alloy, and obtain targets with uniform internal element doping distribution, small grain size, few volume defects and other advantages. The preparation method can effectively reduce the machining workload of the target, and has the advantages of fast production efficiency, high yield and low cost. BRIEF DESCRIPTION OF DRAWINGS

[0037] Figure 1 It is a schematic diagram of a magnesium oxide crucible;

[0038] Figure 2 It is a schematic diagram of a graphite mold;

[0039] Figure 3 It is a Zn-20V target alloy grain size metallographic photo prepared by example 1;

[0040] Figure 4 It is a Zn-1Li target internal flaw photo prepared by example 2. DETAILED DESCRIPTION

[0041] The preparation method of the modified element doped zinc-based alloy sputtering target, adopts the process flow of "inert gas flow protection smelting-high frequency induction heating-immersion feeding-rotating blade uniform stirring-gas-filled centrifugal casting-synchronous water cooling rapid solidification-surface machining", including the following steps:

[0042] (1)Preparation: select the purity of 99.999wt. % Zn; select the modified element as V, Zr, Li, Ti, Al, Ga, Ni one or more, the purity is 99.995wt. %. According to the mass fraction of each element in the alloy, weigh.

[0043] (2) Alloying smelting: the high purity Zn ingot prepared in step (1) is placed in a magnesia ceramic crucible, the modified element is wrapped with high purity Zn foil and placed on the rotating blade of the stirring device, the crucible is covered and placed on the support frame of the heating coil of the centrifugal device; the device is vacuumed to 10 -1 Pa below; then inert gas is introduced, the gas flow rate is maintained, and the gas pressure in the crucible is maintained at 10 4 Pa above; high-frequency induction heating is used, the heating power is 10-25KW, the internal temperature of the crucible is displayed at 570-620℃, and the refining time is 2-5min; the heating power is maintained, the rotating blade is immersed in the Zn melt, and the blade is rotated at a speed of 500-1000n / min for 5-10min, and an alloy melt with uniform element distribution is obtained.

[0044] As Figure 1 shown, the smelting crucible is made of high-strength magnesia crucible, the magnesia crucible body 1 is provided with a cover of the same material, which is fastened by threads, and the cover is provided with gas inlet and outlet pipelines and gas inlet 2 and gas outlet 3, so as to vacuum the inside of the crucible body 1 and introduce and discharge protective gas; the center of the cover is provided with a liftable ceramic rod, and the ceramic rod is provided with a ceramic rotating blade 4; the modified element 5 wrapped with Zn foil is placed on the ceramic rotating blade 4, and after the Zn melt 6 is refined, the rotating blade is immersed in the Zn melt 6, and after a period of time, the blade is rotated to obtain an alloy melt with uniform element distribution. The bottom of the crucible body 1 is provided with a discharge port 7. High-frequency heating coils are arranged around the crucible body 1 to heat the crucible by high-frequency induction. The center of the stirring ceramic rod is provided with an E-type thermocouple for accurate temperature measurement of the crucible furnace. The discharge port 7 is arranged at one side of the bottom of the crucible body 1, and the discharge port 7 is also provided with a matched ceramic plug.

[0045] The crucible used can meet the requirements of vacuum melting and secondary feeding of zinc-based alloy sputtering targets with modified elements for semiconductor coating. It can also avoid zinc vapor phenomenon by evacuating the crucible before melting and filling it with protective inert gas, high-frequency rapid heating, and precise temperature control by immersion thermocouples, thus reducing the zinc content and solving the "zinc fume" problem. The use of this crucible can obtain alloy melt with uniform composition. Secondly, since the dopant metal elements and the host metal elements are prone to forming intermetallic compounds, the melt is prone to agglomeration and separation in a static state, and the dopant elements can settle to the bottom or top layer of the melt. Rapid stirring by rotating blades can ensure the uniform distribution of dopant elements and avoid the agglomeration and precipitation of intermetallic compounds. This results in a target material with advantages such as uniform internal element doping distribution, small grain size, and few volume defects, and is conducive to mass production.

[0046] (3) Centrifugal casting: After the alloy melt obtained in step (2) is rotated and stirred, the rotating blades are automatically lifted, the crucible gas outlet valve is closed, the centrifugal arm is turned on, the centrifugal speed is set to 300-1000 n / min, the centrifugal time is 2-5 min, and the gas filling pressure of the melting crucible during the centrifugation process is set to 15-25 MPa.

[0047] (4) Synchronous water-cooled rapid solidification: The centrifugal casting mold in step (3) is made of high-quality graphite, such as... Figure 2 The diagram shows a graphite mold. The inner cavity size of the graphite mold is 1.05 to 1.2 times the size of the target material. Before starting the centrifuge, the graphite mold is preheated for 5 to 10 minutes by an embedded heating coil at a preheating temperature of 150 to 250°C. After starting the centrifuge, the heating is stopped, and cooling water is continuously supplied to the coil. After the alloy melt fills the graphite mold, it is cooled down simultaneously at a cooling rate of 100 to 150°C / min.

[0048] (5) Surface machining: After the centrifugation in step (4) is completed, the mold temperature drops to below 50°C and the mold is removed from the furnace; the alloy ingot doped with modified elements is machined on the surface of the ingot using a CNC machining center, and the machining size is adjusted to the finished product specifications.

[0049] The method of this invention prepares a zinc-based alloy sputtering target for semiconductor coating with doped and modified elements. The main element is Zn, and the modifying elements are one or more of V, Zr, Li, Ti, Al, Ga, and Ni. The content of the modifying elements is 1.0–20.0 wt.%, with the balance being Zn, and the total impurity content is less than 0.01 wt.%. The alloy sputtering target can be circular, rectangular, or irregularly shaped, with a thickness of 0.3–20 mm and a maximum external dimension of 500 mm. The maximum grain size of the alloy sputtering target is less than 50 μm, the average grain size is not greater than 20 μm, and the internal volume defect is not greater than 0.2%.

[0050] Example 1:

[0051] The Zn-20V alloy target material is prepared, and the circular target material has a finished product size of 8 mm in thickness and 220 mm in diameter.

[0052] (1) Preparation: Zn with a purity of 99.999 wt.% is selected; the modification element V is selected with a purity of 99.995 wt.%. According to the proportion of V element in the alloy of 20 wt.%, the rest is Zn; the total amount of raw materials is 2.5 kg, the V particles are 0.5 kg, the Zn ingot is 1.9 kg, and the Zn foil is 0.1 kg (0.1 mm in thickness), and the weighing is performed.

[0053] (2) Alloying smelting: the high-purity Zn ingot is placed in a magnesia ceramic crucible, the V particles are wrapped with high-purity Zn foil and placed on the rotating blade of the stirring device, the crucible is covered, and placed on the support frame of the heating coil of the centrifugal equipment; the equipment is vacuumed to 10 -1 Pa below; then argon gas is introduced, the gas flow rate is maintained, and the gas pressure in the crucible is maintained at 10 4 Pa above; a high-frequency induction heating method is used, the heating power is 25 KW, the internal temperature of the crucible is displayed as 620℃, and the refining is performed for 5 min; the heating power is maintained, the rotating blade is immersed in the Zn melt, and is static for 10 min; the blade rotation is started, the rotation speed is 1000 n / min, and the rotation time is 5 min, so that the alloy melt with uniform element distribution is obtained.

[0054] (3) Centrifugal casting: after the rotation and stirring of the alloy melt are completed, the rotating blade is automatically lifted, the gas outlet valve of the crucible is closed, the centrifugal arm is opened, the centrifugal speed is set to 500 n / min, and the centrifugal time is 5 min; during the centrifugal process, the smelting crucible is inflated to a pressure of 25 Mpa.

[0055] (4) Synchronous water cooling and rapid solidification: the graphite mold is preheated for 5 min by the embedded heating coil before the centrifugal casting, and the mold preheating temperature is 250℃; after the centrifugal casting is started, the heating is stopped, the coil continuously introduces cooling water, the alloy melt fills the graphite mold, and then the synchronous cooling is performed at a cooling rate of 150℃ / min.

[0056] (5) Surface machining: after the centrifugal casting is completed, the mold temperature is reduced to below 50℃, and the furnace is discharged; the alloy ingot doped with the modification element is subjected to surface machining by using a numerical control machining center, and the machining size is adjusted to the finished product size, i.e., the finished product size is 8 mm in thickness and 220 mm in diameter.

[0057] Example 2:

[0058] The Zn-1Li alloy target material is prepared, and the rectangular target material has a finished product size of 6.35 mm in thickness, 424 mm in length, and 79.4 mm in width.

[0059] (1) Preparation: Zn with a purity of 99.999wt.% is selected; Li is selected as the modification element, with a purity of 99.995wt.%. According to the proportion of Li element in the alloy of 1.0wt.%, the rest is Zn; the total amount of raw materials is 2.0 kg, the amount of Li particles is 0.02 kg, the amount of Zn ingots is 1.95 kg, and the amount of Zn foil is 0.03 kg (thickness 0.1 mm), and the weighing is performed.

[0060] (2) Alloying smelting: the high-purity Zn ingot is placed in a magnesium oxide ceramic crucible, the Li sheet is wrapped with high-purity Zn foil and placed on the rotating blade of the stirring device, the crucible is covered, and placed on the support frame of the heating coil of the centrifugal device; the device is vacuumed to 10 -1 Pa below; then argon inert gas is introduced, the gas flow rate is maintained, and the gas pressure in the crucible is maintained at 10 4 Pa above; high-frequency induction heating is adopted, the heating power is 10 KW, the internal temperature of the crucible is displayed as 570℃, and the refining is performed for 2 min; the heating power is maintained, the rotating blade is immersed in the Zn melt, and the blade is rotated at a speed of 500 n / min for 10 min, and an alloy melt with uniform element distribution is obtained.

[0061] (3) Centrifugal casting: after the alloy melt is rotated and stirred, the rotating blade is automatically lifted, the gas outlet valve of the crucible is closed, the centrifugal arm is opened, the centrifugal speed is set to 1000 n / min, and the centrifugal time is 2 min. The gas pressure in the smelting crucible during the centrifugal process is set to 15 MPa.

[0062] (4) Synchronous water cooling rapid solidification: the graphite mold is preheated for 10 min by the embedded heating coil before the centrifugal casting, and the mold preheating temperature is 150℃; after the centrifugal casting is started, the heating is stopped, and the coil continuously introduces cooling water. After the alloy melt fills the graphite mold, synchronous cooling is performed at a cooling rate of 150℃ / min.

[0063] (5) Surface machining: after the centrifugal casting is completed, the mold temperature is reduced to below 50℃, and the furnace is discharged; the alloy ingot doped with the modification element is subjected to surface machining by using a numerical control machining center, and the machining size is adjusted to the finished product size, i.e., the finished product size is 6.35 mm in thickness, 424 mm in length, and 79.4 mm in width.

[0064] Example 3:

[0065] The Zn-9Ni alloy target material is prepared, and the circular target material has a finished product size of 5 mm in thickness and 355.6 mm in diameter.

[0066] (1) Preparation: Zn with a purity of 99.999 wt.% is selected; the modification element is Ni with a purity of 99.995 wt.%. According to the proportion of the Ni element in the alloy, which is 9.0 wt.%, the rest is Zn; the total amount of the raw materials is 4.0 kg, the amount of Ni particles is 0.36 kg, the amount of Zn ingots is 3.6 kg, and the amount of Zn foils is 0.04 kg (0.1 mm in thickness), and the weighing is performed.

[0067] (2) Alloying smelting: the high-purity Zn ingot is placed in a magnesia ceramic crucible, the Ni sheet is wrapped with high-purity Zn foil and placed on the rotating blade of the stirring device, the crucible is covered, and placed on the support frame of the heating coil of the centrifugal device; the device is vacuumed to 10 Pa below; then argon gas is introduced, the gas flow rate is maintained, and the gas pressure in the crucible is 10 Pa above; the high-frequency induction heating mode is adopted, the heating power is 12 KW, the internal temperature of the crucible is displayed as 600 ℃, and the refining is performed for 5 min; the heating power is maintained, the rotating blade is immersed in the Zn melt, and the blade is rotated at a speed of 1000 n / min for 10 min, and the alloy melt with uniform element distribution is obtained. -1 4 (3) Centrifugal casting: after the rotation and stirring of the alloy melt are completed, the rotating blade is automatically lifted, the gas outlet valve of the crucible is closed, the centrifugal arm is opened, the centrifugal speed is set to 800 n / min, and the centrifugal time is 3.5 min; during the centrifugal process, the smelting crucible is inflated to a pressure of 20 MPa.

[0068] (4) Synchronous water cooling rapid solidification: the graphite mold is preheated for 8 min by the embedded heating coil before the centrifugal casting, and the mold preheating temperature is 200 ℃; after the centrifugal casting is started, the heating is stopped, the coil continuously introduces cooling water, the alloy melt fills the graphite mold, and the synchronous cooling is performed at a cooling rate of 100 ℃ / min.

[0069] (5) Surface machining: after the centrifugal casting is completed, the mold temperature is reduced to below 50 ℃, and the furnace is discharged; the alloy ingot doped with the modification element is subjected to surface machining by using a numerical control machining center, and the machining size is the finished product size, i.e., the finished product size is 5 mm in thickness and 355.6 mm in diameter.

[0070] (5) Surface machining: after the centrifugal casting is completed, the mold temperature is reduced to below 50 ℃, and the furnace is discharged; the alloy ingot doped with the modification element is subjected to surface machining by using a numerical control machining center, and the machining size is the finished product size, i.e., the finished product size is 5 mm in thickness and 355.6 mm in diameter.

[0071] Example 4:

[0072] ​The Zn-5Zr-1V alloy target material is prepared, and the circular target material has a finished product size of 10 mm in thickness, 450 mm in length, and 100 mm in width.

[0073] (1) Preparation: Zn with a purity of 99.999 wt.% is selected; the modification elements are Zr and V, both with a purity of 99.995 wt.%. According to the component proportion of 5.0 wt.% of Zr and 1.0 wt.% of V in the alloy, and the rest being Zn, the total amount of the raw materials is 3.5.0 kg, the Zr particles are 0.175 kg, the V particles are 0.035 kg, the Zn ingot is 3.2 kg, and the Zn foil is 0.09 kg (0.1 mm in thickness), and the weighing is performed.

[0074] (2) Alloying smelting: the high-purity Zn ingot is placed in a magnesia ceramic crucible, the Zr and V are respectively wrapped with high-purity Zn foil and placed on the rotating blades of the stirring device, the crucible is covered, and is placed on the support frame of the heating coil of the centrifugal equipment; the equipment is vacuum-pumped to 10 - 1 Pa below; then argon gas is introduced, the gas flow rate is maintained, the gas pressure in the crucible is 10 4 Pa above; a high-frequency induction heating mode is adopted, the heating power is 20 KW, the internal temperature of the crucible is displayed as 620 ℃, and the refining is performed for 5 min; the heating power is maintained, the rotating blades are immersed in the Zn melt, and are static for 8 min; the blades are rotated at a speed of 1000 n / min, and the rotating time is 10 min, so that the alloy melt with uniform element distribution is obtained.

[0075] (3) Centrifugal casting: after the rotating stirring of the alloy melt is completed, the rotating blades are automatically lifted, the gas outlet valve of the crucible is closed, the centrifugal arm is opened, the centrifugal speed is set to 1000 n / min, and the centrifugal time is 5 min; during the centrifugal process, the smelting crucible is inflated to a pressure of 25 Mpa.

[0076] (4) Synchronous water cooling rapid solidification: the graphite mold is preheated for 8 min by the embedded heating coil before the centrifugal casting, and the mold preheating temperature is 200 ℃; after the centrifugal casting is started, the heating is stopped, the coil continuously introduces cooling water, the alloy melt fills the graphite mold, and synchronous cooling is performed at a cooling rate of 120 ℃ / min.

[0077] (5) Surface machining: after the centrifugal casting is completed, the mold temperature is reduced to below 50 ℃, and the furnace is discharged; the alloy ingot doped with the modification elements is subjected to surface machining by using a numerical control machining center, and the machining size is the finished product size, i.e., the finished product size is 10 mm in thickness, 450 mm in length, and 100 mm in width.

[0078] Example 5:

[0079] A Zn-15Al-2Ti-1Ga alloy target was prepared, which was a circular target with a finished size of 3 mm in thickness and 101.6 mm in diameter.

[0080] (1) Preparation of raw materials: Zn with a purity of 99.999 wt.% was selected; the modification elements were Al, Ti and Ga, each with a purity of 99.995 wt.%. The proportions of Al, Ti and Ga in the alloy were 15.0 wt.%, 2.0 wt.% and 1.0 wt.% respectively, and the rest was Zn; the total amount of raw materials was 0.5 kg, including 0.075 kg of Al blocks, 0.01 kg of Ti blocks, 0.005 kg of Ga blocks, 0.35 kg of Zn ingots and 0.06 kg of Zn foils (0.1 mm in thickness).

[0081] (2) Alloying smelting: the high-purity Zn ingots were placed in a magnesia ceramic crucible, the modification elements Al, Ti and Ga were each wrapped with high-purity Zn foil and placed on the rotating blades of the stirring device, the crucible was covered and placed on the support frame of the heating coil of the centrifugal equipment; the equipment was vacuumed to 10 Pa below; then argon gas was introduced, the gas flow rate was maintained, and the gas pressure inside the crucible was maintained at 10 Pa above; high-frequency induction heating was adopted, the heating power was 15 KW, the temperature inside the crucible was displayed as 590℃, and the refining was performed for 2 min; the heating power was maintained, the rotating blades were immersed in the Zn melt, and the blades were kept still for 6 min; then the blades were rotated at a speed of 600 n / min for 10 min, and an alloy melt with uniform element distribution was obtained. -1 4 (3) Centrifugal casting: after the rotation and stirring of the alloy melt were completed, the rotating blades were automatically lifted, the gas outlet valve of the crucible was closed, the centrifugal arm was opened, the centrifugal speed was set to 600 n / min, and the centrifugal time was 3 min; during the centrifugal process, the smelting crucible was inflated to a pressure of 22 MPa.

[0082] (4) Synchronous water cooling and rapid solidification: the graphite mold for centrifugal casting was selected to be 1.2 times the size of the target, i.e., the inner cavity size was 3.6 mm in thickness and 122 mm in diameter. Before starting the centrifugation, the graphite mold was preheated for 5 min by the embedded heating coil, and the mold preheating temperature was 220℃; after starting the centrifugation, the heating was stopped, and the coil continued to introduce cooling water; after the alloy melt filled the graphite mold, synchronous cooling was performed at a cooling rate of 150℃ / min.

[0083] (4) Synchronous water cooling and rapid solidification: the graphite mold for centrifugal casting was selected to be 1.2 times the size of the target, i.e., the inner cavity size was 3.6 mm in thickness and 122 mm in diameter. Before starting the centrifugation, the graphite mold was preheated for 5 min by the embedded heating coil, and the mold preheating temperature was 220℃; after starting the centrifugation, the heating was stopped, and the coil continued to introduce cooling water; after the alloy melt filled the graphite mold, synchronous cooling was performed at a cooling rate of 150℃ / min.

[0084] ​(5) Surface machining: After centrifugation, the mold temperature drops to below 50°C and the mold is removed from the furnace; the alloy ingot doped with modified elements is machined on the surface of the ingot using a CNC machining center, and the machining size is made up to the finished product size, i.e., the finished product size is 3mm thick and 101.6mm in diameter.

[0085] The semiconductor coating sputtering targets prepared in Examples 1-5 were tested for composition, dimensions, alloy grain size, average grain size, and internal volume defects. The experimental data are shown in Table 1.

[0086] Table 1. Performance of sputtering targets prepared in Examples 1-5

[0087]

[0088] like Figure 3 The image shows a metallographic photograph of the Zn-20V target alloy prepared in Example 1. It can be seen that most of the grains inside the target are polygonal, representing α-Zn hexagonal crystals. Grain boundaries are distinct, and the grains are small and uniform, exhibiting randomness and disordered crystallographic orientation. Numerous gray crystals, irregularly tetragonal, are distributed between the α-Zn hexagonal crystals, primarily VZn3 compound phases, with intergranular bonding approaching 99.9% (density). The alloy grain size was measured to be: a maximum of 21.88 μm, a minimum of 4.92 μm, and an average of 7.6 μm.

[0089] like Figure 4 The image shown is an internal flaw detection photograph of the Zn-1Li target prepared in Example 2. The Zn-1Li alloy target was prepared using this method. The internal quality of the target was scanned using the set non-destructive testing parameters. C-scan images of the defect wave and the bottom wave located between the surface wave and the bottom wave were obtained. No obvious defect wave was found in the images, indicating that the internal quality of the target is good and there are no large-area defects. Calculations show that the internal volume defect of the alloy target is 0.11%.

[0090] The method for preparing a semiconductor coating sputtering target with doped modified elements disclosed in this invention solves the problem of the difficulty in doping zinc-based sputtering targets with active metal elements, obtains an alloy with a high content of doped elements, and the resulting target has the advantages of uniform internal element doping distribution, small grain size, and few volume defects. It also effectively reduces the amount of machining work on the target and has the advantages of fast production efficiency, high yield, and low cost.

[0091] The above-mentioned embodiments only exemplify the embodiments of the sputtering target prepared by doping modification elements of the present application. In the technical solutions of the present application, the content of each metal element in the target alloy can be freely selected within the specified range, which will not be listed one by one here. Therefore, the technical solutions contained in the above description should be regarded as exemplary, rather than limiting the protection scope of the patent application of the present application.

Claims

1. A method for preparing a zinc-based alloy sputtering target doped with modified elements for semiconductor coating, comprising the following steps: (1) Material preparation: The sputtering target is composed of modified elements and Zn. The modified elements are one or more of V, Zr, Li, Ti, Al, Ga and Ni, and the content of the modified elements is 1.0 to 20.0 wt.%, with the balance being Zn. The materials are weighed according to the mass fraction ratio of each element in the alloy. (2) Alloying smelting: Place the Zn ingot into a crucible, wrap the modifying element with high-purity Zn foil and place it on the rotating blades of the stirring device. Seal the crucible and place it on the heating coil support frame of the centrifuge. Evacuate the equipment to 10°C. -1 Below Pa; then an inert gas is introduced, maintaining a constant flow rate, with the gas pressure inside the crucible at 10. 4 Pa or above; using high-frequency induction heating, the Zn ingot is first melted and refined; then, while maintaining the heating power, the rotating blade is immersed in the Zn melt, left to stand for 5 to 10 minutes, and the blade is turned on to rotate, so that the modified elements are melted and dispersed in the Zn melt, and an alloy melt with uniform element distribution is obtained; (3) Centrifugal casting: After the alloy melt in step (2) is rotated and stirred, the rotating blades are automatically raised, the crucible vent valve is closed, the centrifugal arm is turned on, and the centrifugal casting is carried out. (4) Simultaneous water cooling and rapid solidification: The inner cavity size of the centrifugal casting mold is 1.05 to 1.2 times the size of the target material. Before starting the centrifuge, the mold is preheated by an embedded heating coil. After starting the centrifuge, the heating stops, and cooling water is continuously supplied to the coil. After the alloy melt fills the mold, it is cooled down simultaneously. (5) Surface machining: After centrifugal casting is completed and the mold temperature drops below 50°C, the mold is removed from the furnace. The alloy ingots doped with modified elements are surface-machined using a CNC machining center to achieve the finished product dimensions.

2. The method for preparing the zinc-based alloy sputtering target for semiconductor coating according to claim 1, characterized in that: The purity of the raw materials containing the modifying elements V, Zr, Li, Ti, Al, Ga, and Ni is 99.999 wt.%, and the purity of the Zn raw material is 99.995 wt.%.

3. The method for preparing the zinc-based alloy sputtering target for semiconductor coating according to claim 1, characterized in that: The crucible is a magnesium oxide crucible, and the crucible is equipped with a lid of the same material, which is fastened by threads. The crucible lid is equipped with inlet and outlet gas pipes to allow for vacuuming inside the crucible and the entry and exit of protective gas. A ceramic rod with a liftable and rotating blade is located in the center of the crucible lid.

4. The method for preparing the zinc-based alloy sputtering target for semiconductor coating according to claim 1, characterized in that: The high-frequency induction heating power is 10-25kW, the internal temperature of the crucible is 570℃-620℃, and the refining time is 2-5min; the inert gas is nitrogen or argon; when the blade rotates, the rotation speed is 500-1000n / min, and the rotation time is 5-10min.

5. The method for preparing the zinc-based alloy sputtering target for semiconductor coating according to claim 1, characterized in that: During centrifugal casting, the centrifugal speed is 300-1000 n / min, the centrifugation time is 2-5 min, and the gas filling pressure of the melting crucible during centrifugation is set to 15-25 MPa.

6. The method for preparing the zinc-based alloy sputtering target for semiconductor coating according to claim 5, characterized in that: The preheating time for centrifugal casting molds is 5 to 10 minutes, and the preheating temperature is 150 to 250°C.

7. The method for preparing the zinc-based alloy sputtering target for semiconductor coating according to claim 6, characterized in that: During synchronous cooling, the cooling rate is 100–150 °C / min.

8. A zinc-based alloy sputtering target for semiconductor coating, characterized in that: It is prepared by any one of claims 1-7.

9. The zinc-based alloy sputtering target for semiconductor coating according to claim 8, characterized in that: The target material is circular, rectangular, or irregular in shape, with a thickness of 0.3–20 mm and a maximum external dimension of 500 mm.

10. The zinc-based alloy sputtering target for semiconductor coating according to claim 9, characterized in that: The target material has a total impurity content of less than 0.01 wt.%, a maximum grain size of less than 50 μm, an average grain size of no more than 20 μm, and an internal volume defect of no more than 0.2%.

Images