Ultrafine grain aluminum-silicon-copper target material and preparation method thereof

Abstract

The invention relates to the technical field of non-ferrous metal materials and target materials, and provides an ultra-fine grain aluminum-silicon-copper target material and a preparation method thereof. The ultra-fine grain aluminum-silicon-copper target material comprises, by mass, 1%-2% of Si, 0.5%-1% of Cu and the balance Al, and the oxygen content is smaller than or equal to 10 ppm. The grain size of the ultra-fine grain aluminum-silicon-copper target material is smaller than or equal to 1 micron. The ultra-fine grain aluminum-silicon-copper target material which is uniform and fine in grain size, low in oxygen content, high in density and excellent in mechanical property and sputtering property is obtained through the composite process of oxygen control casting, equal-channel extrusion, cold rolling and low-temperature annealing in combination with precise parameter matching, the strict requirements of high-end coating on film flatness and electrical consistency can be met, and the target material is suitable for large-scale production. Meanwhile, the technological process is simple, product quality stability is good, and industrial mass production is facilitated.

Description

Technical Field

[0001] This invention relates to the field of non-ferrous metal materials and target technology, and particularly to an ultrafine crystalline aluminum-silicon-copper target and its preparation method. Background Technology

[0002] In the integrated circuit interconnect material system, aluminum has long dominated metallization processes at process nodes above 90 nm due to its excellent electrical and thermal conductivity, process compatibility, and economy, and maintains an important position in the display and packaging fields. However, as process linewidths enter the nanometer scale, pure aluminum interconnect materials have exposed reliability issues caused by electromigration and stress migration. These effects can lead to void aggregation, interface failure, and open circuits in wires, becoming key obstacles restricting its further miniaturization applications. By introducing small amounts of Si and Cu elements into aluminum to form Al-Si, Al-Cu, and Al-Si-Cu systems, a synergistic improvement in strength and conductivity can be achieved. Si is mainly used to suppress grain growth and improve thermal expansion matching, while Cu can strengthen solid solutions, improve electromigration resistance, and promote grain boundary stabilization. Al-Si-Cu alloy sputtering targets can be used to prepare functional thin films such as semiconductor interconnect layers and display panel electrode layers. Compared with coarse-grained targets, targets with fine grains have a significantly increased number of grain boundaries, resulting in a significantly higher sputtering rate. Therefore, improving the microstructure of Al-Si-Cu alloy targets, such as obtaining fine grains through process control, can increase their sputtering rate.

[0003] One related technology discloses a method for preparing a fine-grained, high-purity aluminum-silicon-copper alloy target blank for sputtering. This method involves preparing an intermediate alloy, melting the intermediate alloy with high-purity aluminum, online refining, bipolar filtration, and casting to obtain the fine-grained, high-purity aluminum-silicon-copper alloy target blank for sputtering. However, this method only mentions that the prepared aluminum-silicon-copper alloy target has an equiaxed crystal structure and uniform composition, without specifying the grain size. Another related technology discloses a high-purity aluminum-silicon-copper target material and its preparation method and application. This method involves homogenization annealing, multi-directional forging, solution treatment, alternating longitudinal and transverse cold rolling, recrystallization annealing, rough machining, bonding, finish machining, and surface treatment to obtain the aluminum-silicon-copper target material. The target material has a uniformly distributed precipitate phase and an average grain size of approximately 100 µm.

[0004] Currently, most existing methods for preparing aluminum-silicon-copper sputtering targets employ the traditional process of "casting-forging-hot rolling-cold rolling-annealing," but this process has significant drawbacks: cast alloys are prone to compositional segregation, coarse cast grains, and defects such as porosity and gas bubbles, which are difficult to completely eliminate during subsequent hot / cold rolling. This results in a large target grain size (typically 50-80 μm) and poor microstructure uniformity, leading to still poor sputtering performance. Furthermore, none of the aforementioned existing technologies control the oxygen content of the target material. The oxides in aluminum-silicon-copper targets are high-resistivity insulating phases, which easily cause sputtering arcing, voltage and current fluctuations, and disrupt process stability. Their high sputtering threshold reduces and fluctuates the sputtering rate. Simultaneously, oxide particle splashing introduces thin film impurities and defects, which can also ablate the target material, reduce utilization, contaminate the cavity, and exacerbate equipment wear.

[0005] In summary, there is an urgent need to provide an aluminum-copper-silicon sputtering target with fine grain size, low oxygen content, and excellent sputtering performance to meet the requirements of high-end coating. Summary of the Invention

[0006] In view of this, the present invention provides an ultrafine-grained aluminum-silicon-copper sputtering target and its preparation method. The ultrafine-grained aluminum-silicon-copper sputtering target provided by the present invention has a grain size of less than 1 μm, an oxygen content of ≤10 ppm, uniform grain size, high density, good mechanical properties, and excellent sputtering performance.

[0007] To achieve the above-mentioned objectives, the present invention provides the following technical solution: An ultrafine-grained aluminum-silicon-copper target material comprises the following components by mass percentage: Si 1~2%, Cu 0.5~1%, with the balance being Al; the grain size of the ultrafine-grained aluminum-silicon-copper target material is ≤1μm, and the oxygen content is ≤10ppm.

[0008] Preferably, the ultrafine crystalline aluminum-silicon-copper target has a density ≥99.5%, a hardness of 75~100 HV, and an elongation ≥10%.

[0009] This invention also provides a method for preparing the ultrafine-grained aluminum-silicon-copper target described above, comprising the following steps: The raw materials are melted to obtain molten metal; the molten metal is then subjected to hydrogen deoxygenation and rare earth element deoxygenation in sequence, followed by casting and cooling, and the part of the ingot containing rare earth oxides is removed to obtain a qualified ingot. The qualified ingot is subjected to homogenization treatment, equal channel extrusion, cold rolling and annealing in sequence to obtain the ultrafine crystalline aluminum-silicon-copper target material; the channel angle of the die used for equal channel extrusion is 90~120°; the total deformation of the cold rolling process is 80~95%; the annealing temperature is 200~300℃.

[0010] Preferably, the raw materials are industrial pure aluminum, silicon powder, and electrolytic copper; the purity of the industrial pure aluminum is ≥99.999%, the purity of the silicon powder is ≥99.999%, and the purity of the electrolytic copper is ≥99.999%; the melting temperature is 720~760℃, the stirring speed is 300~500 r / min, and the stirring time is 5~10 min; The hydrogen deoxygenation time is 5-10 minutes, and the hydrogen pressure is 0.05-0.3 Pa; the rare earth elements include one or more of lanthanum, cerium, and yttrium; The homogenization treatment is carried out at a temperature of 480~520℃ and a holding time of 4~6h.

[0011] Preferably, the die used for the equal channel extrusion is made of cemented carbide with a surface roughness Ra≤0.2μm; The extrusion speed of the equal channel extrusion is 2~5 mm / s; the number of passes of the equal channel extrusion is 2~4, and the ingot is rotated 90° after each extrusion; before the equal channel extrusion, the ingot and the mold are preheated respectively, the preheating temperature is 100~200℃, and the holding time is 1~2h.

[0012] Preferably, the deformation per pass in the cold rolling process is 20-30%, and the rolling speed is 0.5-1.5 m / s.

[0013] Preferably, the holding time for the annealing treatment is 2 to 4 hours.

[0014] Preferably, after the annealing process, the resulting target material is further subjected to mechanical processing.

[0015] The present invention also provides the application of the ultrafine-grained aluminum-silicon-copper target material described in the above-described scheme or the ultrafine-grained aluminum-silicon-copper target material prepared by the preparation method described in the above-described scheme in magnetron sputtering coating.

[0016] Preferably, the magnetron sputtering coating includes the preparation of a semiconductor interconnect layer, a display panel electrode layer, or a solar cell coating layer.

[0017] This invention provides an ultrafine-grained aluminum-silicon-copper sputtering target, comprising the following components by mass percentage: Si 1~2%, Cu 0.5~1%, and the balance Al; the grain size of the ultrafine-grained aluminum-silicon-copper sputtering target is ≤1μm, and the oxygen content is ≤10ppm. The ultrafine-grained aluminum-silicon-copper sputtering target provided by this invention has a grain size ≤1μm and a uniform ultrafine-grained structure, solving the problems of coarse grains and uneven structure in traditional processes; furthermore, the ultrafine-grained aluminum-silicon-copper sputtering target provided by this invention has excellent comprehensive performance: target density ≥99.5%, free from defects such as porosity and pores, hardness up to 75~100 HV, and elongation ≥10%; under standard magnetron sputtering process conditions (vacuum degree 1×10⁻⁶), it can achieve high performance. -3 ~5×10-3 With an argon pressure of 0.3~0.8 Pa and a sputtering power of 150~250 W, the sputtering rate is stable, and the atomic escape uniformity is significantly better than that of traditional targets. The surface roughness of the prepared film Ra is ≤0.1 μm, and the compositional uniformity deviation is ≤0.1%, which can meet the stringent requirements of high-end coating for film flatness and electrical consistency. The ultrafine-grained aluminum-silicon-copper target provided by this invention can meet the sputtering coating needs of high-end fields such as semiconductors, display panels, and solar cells, and is especially suitable for scenarios with stringent requirements for film uniformity and electrical performance, showing broad application prospects.

[0018] This invention also provides a method for preparing the ultrafine-grained aluminum-silicon-copper target material described above, comprising the following steps: melting raw materials to obtain molten metal; subjecting the molten metal to hydrogen deoxygenation and rare earth element deoxygenation sequentially, followed by casting and cooling, and removing the portion of the ingot containing rare earth oxides to obtain a qualified ingot; subjecting the qualified ingot to homogenization treatment, equal channel extrusion (ECAP), cold rolling, and annealing to obtain the ultrafine-grained aluminum-silicon-copper target material. Rare earth elements have extremely strong deoxidation capabilities (superior to conventional elements such as aluminum, magnesium, and titanium). This invention, by adding rare earth elements to the melt and combining it with the hydrogen gas introduction process, removes oxygen from the melt through a dual-effect process, significantly improving deoxidation efficiency, thereby effectively controlling the oxygen content in the finished target material to within 10 ppm. Simultaneously, this invention achieves composite intense plastic deformation through "ECAP + cold rolling," combined with annealing, which can stably control the grain size of the target material to ≤1 μm, forming a uniform ultrafine-grained structure, solving the problems of coarse grains and uneven structure in traditional processes.

[0019] Furthermore, this invention clarifies the matching parameters of the ECAP mold angle, cold rolling deformation amount, and low-temperature annealing temperature, avoiding the limitations of a single process. It can take into account grain refinement, microstructure uniformity, and target material forming size, achieving precise control of ultrafine grain structure, second phase regulation, and comprehensive target material performance, reducing the risk of billet cracking during production, and is suitable for industrial mass production. Attached Figure Description

[0020] Figure 1 The images show the microstructure of the ultrafine-grained aluminum-silicon-copper target material prepared in Example 1, including (a) a bright-field TEM image, (b) an Al elemental distribution map, (c) a Si elemental distribution map, and (d) a Cu elemental distribution map. Figure 2 The image shows the EBSD grain boundary diagram of the ultrafine-grained aluminum-silicon-copper target material prepared in Example 2. Detailed Implementation

[0021] This invention provides an ultrafine-grained aluminum-silicon-copper target material, comprising the following components by mass percentage: Si 1~2%, Cu 0.5~1%, with the balance being Al; the grain size of the ultrafine-grained aluminum-silicon-copper target material is ≤1μm, and the oxygen content is ≤10ppm.

[0022] The ultrafine crystalline aluminum-silicon-copper target provided by the present invention comprises 1-2% Si by mass fraction, specifically 1%, 1.5% or 2%.

[0023] The ultrafine crystalline aluminum-silicon-copper target provided by the present invention comprises 0.5-1% Cu by mass fraction, specifically 1%.

[0024] The ultrafine crystalline aluminum-silicon-copper target provided by this invention comprises the remainder Al by mass fraction.

[0025] In this invention, the grain size of the ultrafine crystalline aluminum-silicon-copper target is ≤1μm, and in the embodiments it is 0.5, 0.6 or 0.8μm.

[0026] In this invention, the oxygen content of the ultrafine-grained aluminum-silicon-copper target provided by this invention is ≤10ppm. By controlling the oxygen content of the aluminum-silicon-copper target, this invention can avoid the formation of hard oxide inclusions, ensure the processing performance of the target and the stability of the sputtering process, prevent sputtered film particle contamination and electrical performance degradation, and ultimately ensure the reliability and yield of high-end devices such as semiconductors and display panels.

[0027] In this invention, the ultrafine-grained aluminum-silicon-copper target material has a density ≥99.5%, is free from defects such as porosity and pores, has a hardness of 75~100 HV (85~92 HV in the examples), and an elongation ≥8%, preferably greater than 10% (15~23% in the examples). In a specific embodiment of this invention, the compositional uniformity deviation of the ultrafine-grained aluminum-silicon-copper target material is ≤0.12%.

[0028] The present invention also provides a method for preparing the ultrafine crystalline aluminum-silicon-copper target material described above, comprising the following steps: The raw materials are melted to obtain molten metal; the molten metal is then subjected to hydrogen deoxygenation and rare earth element deoxygenation in sequence, followed by casting and cooling, and the part of the ingot containing rare earth oxides is removed to obtain a qualified ingot. The qualified ingot is subjected to homogenization treatment, equal channel extrusion, cold rolling and annealing in sequence to obtain the ultrafine crystalline aluminum-silicon-copper target material; the channel angle of the die used for equal channel extrusion is 90~120°; the total deformation of the cold rolling process is 80~95%; the annealing temperature is 200~300℃.

[0029] This invention involves melting raw materials to obtain molten metal. In this invention, the raw materials are preferably industrial pure aluminum, silicon powder, and electrolytic copper; the purity of the industrial pure aluminum is preferably ≥99.999%, the purity of the silicon powder is preferably ≥99.999%, and the purity of the electrolytic copper is preferably ≥99.999%; the melting temperature is preferably 720~760℃, specifically 730℃, 740℃, or 750℃; the stirring speed is 300~500 r / min, specifically 350, 400, or 500 r / min; and the stirring time is 5~10 min, specifically 7, 8, or 10 min; the melting is preferably carried out in a vacuum induction melting furnace, and preferably under inert gas protection, preferably argon; this invention eliminates component segregation through stirring.

[0030] After obtaining the molten metal, the present invention sequentially performs hydrogen deoxygenation and rare earth element deoxygenation on the molten metal, followed by casting and cooling, and removing the portion of the ingot containing rare earth oxides to obtain a qualified ingot. In the present invention, the hydrogen deoxygenation time is preferably 5-10 minutes, specifically 5, 7, or 10 minutes; the hydrogen pressure is preferably 0.05-0.3 Pa, specifically 0.05, 0.1, or 0.2 Pa; the rare earth elements preferably include one or more of La, Ce, and Yttrium; the amount of rare earth elements added is preferably 0.01 g to 0.1 g per kilogram of aluminum-silicon-copper alloy; the rare earth element deoxygenation time is preferably 1-10 minutes. The casting mold is preferably a metal mold, which is preferably preheated before use. The preheating temperature is preferably 200~250℃, specifically 220℃, 230℃, or 240℃. After casting, it is preferably allowed to cool naturally to room temperature to obtain an ingot. Then, the part containing rare earth oxides at the head of the ingot is removed, and the remaining ingot is the qualified ingot of the present invention. In the present invention, the size of the ingot is preferably adjusted according to the specifications of the mold used for subsequent equal-channel extrusion. In a specific embodiment of the present invention, the size of the ingot can be Φ80~120mm×200~300mm.

[0031] After obtaining the ingot, the present invention performs a homogenization treatment on the ingot. In the present invention, the temperature of the homogenization treatment is preferably 480~520℃, specifically 490℃, 500℃ or 510℃, and the holding time is preferably 4~6h, specifically 4.5, 5 or 5.5h; after the homogenization treatment, it is preferably cooled to room temperature in the furnace; the present invention eliminates internal stress, compositional segregation and casting defects inside the ingot through homogenization treatment, improves the plasticity of the ingot, and prepares it for subsequent severe plastic deformation.

[0032] After homogenization, the homogenized ingot is subjected to equal-channel extrusion. In this invention, the channel angle (Φ) of the die used for equal-channel extrusion (denoted as ECAP die) is 90~120°, specifically 90°, 105°, or 120°. By controlling the channel angle within this range, this invention can balance grain refinement and process stability. The ECAP die is preferably made of cemented carbide with a surface roughness Ra≤0.2μm. In a specific embodiment of this invention, the ECAP die is preferably polished before use to meet the roughness requirements.

[0033] In this invention, the extrusion speed of the equal channel extrusion is preferably 2~5 mm / s, specifically 2.5, 3 or 4 mm / s; the number of passes of the equal channel extrusion is preferably 2~4, specifically 2, 3 or 4 passes, and after each extrusion, the ingot is preferably rotated 90° to ensure uniform deformation; the equipment used for the equal channel extrusion is preferably a hydraulic ECAP device; in a specific embodiment of this invention, the surface of the homogenized ingot is preferably ground to remove the oxide scale, then a lubricant is applied, and then equal channel extrusion is performed; the lubricant is preferably graphite, and this invention can improve the lubrication effect and reduce mold wear by applying the lubricant; before performing equal channel extrusion, this invention preferably preheats the ingot and the mold respectively, and the preheating temperature of the ingot and the mold is preferably 100~200℃, specifically 120℃, 150℃ or 190℃, and the holding time is preferably 1~2h, specifically 1, 1.5 or 2h. This invention utilizes equal-channel extrusion to initially refine the grain size of an ingot to 5-10 μm, while simultaneously forming a dense microstructure. The resulting product is a bar.

[0034] Equal channel extrusion (ECCAP), as a technique for intense plastic deformation, can significantly refine grains through shear deformation while maintaining a constant material volume, avoiding the thickness limitations of conventional rolling. However, ECAP suffers from problems such as insufficient deformation uniformity, poor surface quality, and limited dimensions. Furthermore, parameters such as die angle and extrusion passes significantly affect the grain refinement effect. This invention synergistically optimizes ECAP with cold rolling and low-temperature annealing processes, and controls the ECAP die angle, cold rolling deformation amount, and low-temperature annealing temperature. This approach can balance grain refinement, microstructure uniformity, and target forming dimensions, achieving precise control over ultrafine grain structure, second-phase regulation, and overall target performance.

[0035] After compression through the channel, the resulting bar is cold-rolled. In this invention, the deformation per pass in the cold rolling process is preferably 20-30%, specifically 23%, 23.5%, or 30%, and the total deformation is 80-95%, specifically 90%, 92%, or 94%. The rolling speed is preferably 0.5-1.5 m / s, specifically 0.8, 1, or 1.2 m / s. During the cold rolling process, the axis of the bar is parallel to the rolling direction; rolling oil is preferably used for lubrication during the cold rolling process; after cold rolling, a target billet with a thickness of 5-10 mm is obtained; this invention can further break down grains and store a large number of dislocations through cold rolling.

[0036] After cold rolling, the resulting target billet is annealed. In this invention, the annealing temperature is 200-300℃, specifically 250℃, 260℃, or 280℃, and the holding time is preferably 2-4 hours, specifically 2, 2.5, or 3 hours. The annealing is preferably performed in a vacuum heat treatment furnace, preferably under nitrogen or inert gas protection, specifically argon. After annealing, it is preferably cooled to room temperature in the furnace. Traditional annealing processes have high temperatures (above 350℃), which easily induces abnormal grain growth, reducing the target material's performance and failing to meet the requirements of high-end coatings for ultrafine-grained targets. This invention uses low-temperature annealing, which can eliminate cold-rolled internal stress (stress elimination rate ≥90%) while avoiding abnormal grain growth, ultimately obtaining an ultrafine-grained structure with a grain size ≤1μm.

[0037] In this invention, after the annealing treatment, it is preferable to further perform machining on the obtained target material. Specifically, the machining can be milling and / or turning, to obtain a finished target material that meets the dimensional requirements. In a specific embodiment of this invention, the diameter of the finished target material is 200~400mm and the thickness is 5~10mm. After obtaining the finished target material, it is preferable to perform performance testing on the finished target material. The performance testing includes grain size, density, hardness, compositional uniformity, etc., to ensure that the requirements for use are met.

[0038] This invention also provides the application of the ultrafine-grained aluminum-silicon-copper target material described above, or the ultrafine-grained aluminum-silicon-copper target material described above, in magnetron sputtering coating. In this invention, the magnetron sputtering coating preferably includes the preparation of a semiconductor interconnect layer, a display panel electrode layer, or a solar cell coating layer; the substrate for the magnetron sputtering coating can be a 6-12 inch wafer or a substrate of equivalent specifications. The ultrafine-grained aluminum-silicon-copper target material provided by this invention has fine grains, high density, high hardness and elongation, stable sputtering rate, low roughness of the resulting film, and good compositional uniformity, which can meet the stringent requirements of high-end coatings for film flatness and electrical consistency, and is particularly suitable for sputtering coating in the fields of semiconductors, display panels, and solar cells.

[0039] The technical solutions of this invention will be clearly and completely described below with reference to the embodiments thereof. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0040] The raw materials used in the following examples are all industrial pure aluminum with a purity of ≥99.999%, silicon powder with a purity of ≥99.999%, and electrolytic copper with a purity of ≥99.999%.

[0041] Example 1 This embodiment prepares an ultrafine-grained aluminum-silicon-copper target material, with the following composition by mass percentage: Si 1.5%, Cu 0.5%, and the balance Al. The preparation steps are as follows: (1) Melting and casting: Select the corresponding raw materials, melt them in a vacuum induction melting furnace at 740℃, stir at 400r / min, stir for 8min, introduce 0.1Pa hydrogen for 5 minutes, and then add rare earth element lanthanum (add at a ratio of 0.05g lanthanum per kilogram of aluminum-silicon-copper alloy). After adding, keep the metal in liquid state for 5 minutes to remove oxygen in the melt. Cast the resulting molten metal into a 220℃ metal mold, and after cooling, obtain a Φ100mm×250mm ingot. Cut off the part of the ingot head containing rare earth oxides to obtain a qualified ingot.

[0042] (2) Homogenization treatment: keep warm at 490℃ for 5 hours, and then cool to room temperature with the furnace.

[0043] (3) ECAP treatment: Using an ECAP mold with Φ=90°, the ingot and mold are preheated to 120°C and kept at that temperature for 1.5h. Graphite lubrication is used, and the extrusion speed is 3mm / s. Three extrusion passes are performed (adjacent passes rotate 90°) to obtain a bar billet with a grain size of about 10μm.

[0044] (4) Cold rolling: room temperature cold rolling, bar axis parallel to rolling direction, deformation of 30% per pass, total deformation of 90%, rolling speed of 1.0m / s, finally obtaining a billet with a thickness of 10 mm.

[0045] (5) Low-temperature annealing: The material is held at 250℃ for 3 hours in a vacuum furnace under argon protection and then cooled with the furnace to obtain an ultrafine-grained aluminum-silicon-copper target. The grain size of the palladium material is 0.6 μm (e.g., Figure 1 As shown in the figure, its microstructure is uniform and contains only a diffusely distributed silicon-rich phase.

[0046] (6) Subsequent processing: The annealed target material was machined into finished target material, and then its performance was tested. The test results showed that the target material hardness was 92HV, the elongation was 15%, the composition uniformity deviation was ≤0.1%, the oxygen content was 8ppm, and the density was 99.5%; sputtering performance test (vacuum degree 3×10 -3 (Pa, argon pressure 0.5Pa, sputtering power 200W): sputtering rate 2.8nm / s, surface roughness Ra=0.08μm, thin film resistivity 1.12×10⁻⁶. -6 Ω·m.

[0047] Example 2 This embodiment prepares an ultrafine-grained aluminum-silicon-copper target material, with the following composition by mass percentage: Si 2%, Cu 1%, and the balance Al. The preparation steps are as follows: (1) Melting and casting: Select the corresponding raw materials, melt them in a vacuum induction melting furnace at 750°C, stir at 500r / min for 10min, introduce hydrogen gas at 0.05Pa for 6 minutes, and then add rare earth element cerium (add 0.01g of cerium per kilogram of aluminum-silicon-copper alloy). After adding, keep the metal in liquid state for 10 minutes to remove oxygen from the melt. Cast the metal into a 240°C metal mold to obtain a Φ120mm×300mm ingot. Cut off the part of the ingot head containing rare earth oxides to obtain a qualified ingot.

[0048] (2) Homogenization treatment: keep at 510℃ for 4.5h, and then cool with the furnace.

[0049] (3) ECAP treatment: Using an ECAP mold with Φ=105°, preheat to 150°C, keep warm for 2 hours, use graphite lubrication, extrusion speed 4mm / s, 4 extrusion passes (adjacent passes rotate 90°) to obtain a bar billet with a grain size of about 8 μm.

[0050] (4) Cold rolling: room temperature cold rolling, bar axis parallel to rolling direction, deformation per pass 23%, total deformation 92%, rolling speed 1.2m / s, to obtain a 10mm thick billet.

[0051] (5) Low-temperature annealing: Hold at 260℃ for 2.5h under argon protection, and cool with the furnace to obtain ultrafine-grained aluminum-silicon-copper target material with a grain size of 0.5 μm (e.g., Figure 2 As shown in the figure, its microstructure is uniform and contains only a diffusely distributed silicon-rich phase.

[0052] (6) Subsequent processing: The annealed target material was machined into finished target material, and then its performance was tested. The test results showed that the hardness of the target material was 95HV, the elongation was 18%, the composition uniformity deviation was ≤0.08%, the oxygen content was 6ppm, and the density was 99.6%; sputtering performance test (vacuum degree 2×10-3 (Argon pressure 0.6 Pa, sputtering power 220 W): Sputtering rate 3.1 nm / s, rate fluctuation ±1.0%, film surface roughness Ra = 0.08 μm, film resistivity 1.21 × 10⁻⁶. -6 Ω·m.

[0053] Example 3 This embodiment prepares an ultrafine-grained aluminum-silicon-copper target material, with the following composition by mass percentage: Si 1%, Cu 1%, and the balance Al. The preparation steps are as follows: (1) Smelting and casting: Select the corresponding raw materials, melt them in a vacuum induction melting furnace at 730°C, stir at 350 r / min for 7 min, introduce hydrogen gas at 0.2 Pa for 10 min, and then add rare earth elements cerium and yttrium (add 0.1 g of cerium and yttrium per kilogram of aluminum-silicon-copper alloy (mass ratio of cerium and yttrium is 1:1)). After adding, keep the metal in liquid state for 1 minute to remove oxygen from the melt, and cast it into a metal mold at 230°C to obtain an ingot of Φ80mm×200mm. Cut off the part of the ingot head containing rare earth oxides to obtain a qualified ingot.

[0054] (2) Homogenization treatment: keep at 500℃ for 5.5h, and then cool with the furnace.

[0055] (3) ECAP treatment: Using an ECAP mold with Φ=120°, preheat to 190°C, keep warm for 1 hour, use graphite lubrication, extrusion speed 2.5mm / s, extrusion in 2 passes (adjacent passes rotate 90°) to obtain a bar billet with a grain size of about 12μm.

[0056] (4) Cold rolling: room temperature cold rolling, bar axis parallel to rolling direction, deformation per pass 23.5%, total deformation 94%, rolling speed 0.8m / s, to obtain a 5mm thick billet.

[0057] (5) Low temperature annealing: Hold at 280℃ for 2h, under argon protection, and cool with the furnace to obtain ultrafine crystalline aluminum-silicon-copper target material. The grain size of palladium material is 0.8 μm, and its microstructure is uniform, containing only dispersed silicon-rich phase.

[0058] (6) Subsequent processing: The annealed target material was machined into finished target material, and then its performance was tested. The test results showed that the target material hardness was 85HV, the elongation was 23%, the composition uniformity deviation was ≤0.12%, the oxygen content was 3 ppm, and the density was 99.7%; sputtering performance test (vacuum degree 4×10 -3 (Pa, argon pressure 0.4Pa, sputtering power 180W): sputtering rate 2.5nm / s, film surface roughness Ra=0.09μm, film resistivity 1.08×10⁻⁶. -6 Ω·m.

[0059] Comparative Example 1 An aluminum-silicon-copper sputtering target with the same composition as in Example 1 was prepared using a traditional "casting-hot rolling-cold rolling-high-temperature annealing" process. The specific steps are as follows: (1) Select the corresponding raw materials, melt them in a vacuum induction melting furnace at 740℃, stir at 400r / min, stir for 8min, pour them into a 220℃ metal mold, and obtain Φ100mm×250mm ingots after cooling; (2) Homogenization treatment: keep at 490℃ for 5 hours, then cool to room temperature with the furnace; (3) Hot rolling treatment: hot rolling temperature 450℃, deformation per pass 30%, total deformation 90%, rolling speed 1.0m / s; (4) Annealing treatment: Annealing temperature 380℃. After that, it is machined into a finished target material with a final target material grain size of 50 μm. It contains both silicon-rich phase and Al2Cu precipitates, and the distribution is uneven.

[0060] Performance testing of the target material showed that it had a hardness of 72 HV, an elongation of 6.5%, an oxygen content of 150 ppm, and a density of 99.1%. This was achieved under the same sputtering test conditions as in Example 1 (vacuum degree 3 × 10⁻⁶). -3 Under conditions of argon pressure 0.5 Pa, sputtering power 200 W, and a sputtering rate of 1.5 nm / s, the surface roughness of the prepared film Ra = 0.16 μm, which is twice that of Example 1, and the film resistivity is 1.81 × 10⁻⁶. -6 The Ω·m and compositional uniformity deviation of 0.35% cannot meet the requirements of high-end fields for coating precision and stability, further proving the superiority of the process and product of this invention.

[0061] In summary, this invention provides an ultrafine-grained aluminum-silicon-copper sputtering target, its preparation method, and its application. Through a composite process of "oxygen-controlled casting + equal-channel extrusion + cold rolling + low-temperature annealing" combined with precise parameter matching, an ultrafine-grained aluminum-silicon-copper sputtering target with uniform grain size, high density, and excellent mechanical and sputtering properties is obtained. At the same time, the process flow is simplified, mass production stability is improved, and the needs of high-end coating fields are met.

[0062] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. An ultrafine-grained aluminum-silicon-copper sputtering target, characterized in that, The composition includes the following components by mass percentage: Si 1~2%, Cu 0.5~1%, with the balance being Al; the grain size of the ultrafine crystalline aluminum-silicon-copper target is ≤1μm, and the oxygen content is ≤10ppm.

2. The ultrafine-grained aluminum-silicon-copper target material according to claim 1, characterized in that, The ultrafine crystalline aluminum-silicon-copper target has a density of ≥99.5%, a hardness of 75~100 HV, and an elongation of ≥10%.

3. The method for preparing the ultrafine-grained aluminum-silicon-copper target material according to claim 1 or 2, characterized in that, Includes the following steps: The raw materials are melted to obtain molten metal; the molten metal is then subjected to hydrogen deoxygenation and rare earth element deoxygenation in sequence, followed by casting and cooling, and the part of the ingot containing rare earth oxides is removed to obtain a qualified ingot. The qualified ingot is subjected to homogenization treatment, equal channel extrusion, cold rolling and annealing in sequence to obtain the ultrafine crystalline aluminum-silicon-copper target material; the channel angle of the die used for equal channel extrusion is 90~120°; the total deformation of the cold rolling process is 80~95%; the annealing temperature is 200~300℃.

4. The preparation method according to claim 3, characterized in that, The raw materials are industrial pure aluminum, silicon powder, and electrolytic copper; the purity of the industrial pure aluminum is ≥99.999%, the purity of the silicon powder is ≥99.999%, and the purity of the electrolytic copper is ≥99.999%; the melting temperature is 720~760℃, the stirring speed is 300~500r / min, and the stirring time is 5~10min. The hydrogen deoxygenation time is 5-10 minutes, and the hydrogen pressure is 0.05-0.3 Pa; the rare earth elements include one or more of lanthanum, cerium, and yttrium; The homogenization treatment is carried out at a temperature of 480~520℃ and a holding time of 4~6h.

5. The preparation method according to claim 3, characterized in that, The die used for the equal channel extrusion is made of cemented carbide with a surface roughness Ra≤0.2μm; The extrusion speed of the equal channel extrusion is 2~5 mm / s; the number of passes of the equal channel extrusion is 2~4, and the ingot is rotated 90° after each extrusion; before the equal channel extrusion, the ingot and the mold are preheated respectively, the preheating temperature is 100~200℃, and the holding time is 1~2h.

6. The preparation method according to claim 3, characterized in that, The deformation per pass in the cold rolling process is 20-30%, and the rolling speed is 0.5-1.5 m / s.

7. The preparation method according to claim 3, characterized in that, The holding time for the annealing treatment is 2-4 hours.

8. The preparation method according to claim 3, characterized in that, The annealing process also includes machining the resulting target material.

9. The application of the ultrafine-grained aluminum-silicon-copper target material according to claim 1 or 2, or the ultrafine-grained aluminum-silicon-copper target material prepared by the preparation method according to any one of claims 3 to 8, in magnetron sputtering coating.

10. The application according to claim 9, characterized in that, The magnetron sputtering coating includes the preparation of a semiconductor interconnect layer, a display panel electrode layer, or a solar cell coating layer.

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