A method for preparing a planar copper target and a magnetron sputtering method using the same

Abstract

The present invention belongs to the technical field of sputtering targets, and particularly relates to a method for preparing a planar copper target and a magnetron sputtering method using the same. The method comprises the following steps: step S1: preparing a high-purity oxygen-free copper rod; step S2: continuously extruding the oxygen-free copper rod to form a blank, and performing anti-oxidation protection on the blank during the extrusion process; step S3: performing a single-pass low-deformation drawing operation on the blank after cooling to room temperature, controlling the drawing deformation to be 1.5%-3%, and controlling the drawing deformation temperature to be 300°C-500°C; step S4: repeating the above steps S2 and S3 at least twice; step S5: straightening the blank; and step S6: machining the blank to form a copper target. The planar copper target obtained by the preparation method has a grain size of less than 40 μm, fine and uniform grains, and a simple production process, thereby achieving low-cost, high-reliability industrial continuous production.

Description

Technical Field

[0001] The present invention belongs to the technical field of sputtering targets, and in particular relates to a method for preparing a planar copper target and a magnetron sputtering method using the same. Background Art

[0002] Against the backdrop of rapid development of the electronics and information industries, the material requirements for sputtering metal targets are becoming increasingly higher and have become the main factor in application performance. Among them, copper targets are widely used due to their extremely high electrical conductivity, excellent thermal conductivity, corrosion resistance, anti-electromigration ability and base dielectric constant. They are used to reduce the resistance of interconnects between electronic devices and improve their computing speed. They have become an indispensable key material for the development of the display industry and the solar energy industry.

[0003] The working principle of magnetron sputtering is to use an accelerated ion flow with high energy to bombard the surface of the target material. The sputtered target atoms are deposited on the surface of the substrate in the form of a thin film, thereby realizing the coating process of the substrate material. Magnetron sputtering is used in various chips, displays, information storage and various electronic control devices. In the existing technology, copper target is the target material commonly used in the vacuum sputtering process.

[0004] Regarding the target material's organizational structure, producing a copper target with small and uniform grains, a dense interior, no defects, and small grain orientation differences has a great impact on the performance and application environment of sputtering products. Therefore, the requirements for the material composition and preparation process are extremely strict. Copper targets with fine grain size have a more uniform thickness distribution of the sputtered film and can improve its sputtering rate. Obtaining a structure with similar orientation on the basis of controlling the grain size is also an important condition for achieving high-quality coating.

[0005] In the prior art, the preparation of copper targets is mainly carried out by controlling their microstructure through the cooperation of deformation processes such as hot forging, rolling, and static pressing. However, targets prepared by such methods alone have problems such as large grain size, uneven cutting, and inconsistent grain orientation. To address the problems existing in the prior art, those skilled in the art have made many attempts. For example, Chinese patent application CN110578126B discloses a method for preparing multi-specification high-purity copper targets, in which a high-purity copper target with an average grain size of ≤80 μm is obtained by performing multiple hot rolling on a heated billet and then cooling it to room temperature, and then flattening, cutting, rough machining, and fine machining. However, the grain size of the copper target prepared by this method is still large, and the effect is insufficient. Summary of the Invention

[0006] To solve the above problems, the present invention proposes a method for preparing a planar copper target and a magnetron sputtering method using the same. The production process is simple and can produce a target with a grain size of less than 40 μm.

[0007] To achieve the above object, the present invention proposes a method for preparing a planar copper target, which is characterized by comprising:

[0008] Step S1: preparing a high-purity oxygen-free copper rod;

[0009] Step S2: continuously extruding the oxygen-free copper rod to form a billet, and performing anti-oxidation protection on the billet during the extrusion process;

[0010] Step S3: After the blank is cooled to room temperature, a single-pass low-deformation drawing operation is performed, wherein the drawing deformation is controlled to be 1.5%-3%, and the drawing deformation temperature is controlled to be 300° C.-500° C.;

[0011] Step S4: Repeat the above steps S2 and S3 at least twice;

[0012] Step S5: performing straightening operation on the blank;

[0013] Step S6: machining the blank to produce a copper target.

[0014] Furthermore, in step S2, a continuous extruder is used to perform a continuous extrusion operation, and an anti-oxidation cooling circulation device is used to cool the billet to room temperature.

[0015] The copper billet is protected by an anti-oxidation cooling device so that it will not be oxidized at high temperatures, thus ensuring the reliability of the copper billet composition.

[0016] Furthermore, the continuous extruder is provided with an extrusion wheel and an extrusion die, and the rotation speed of the extrusion wheel is 2-3 r / min;

[0017] The extrusion die comprises an upper die (41) and a lower die (42), wherein the upper die (41) and the lower die (42) are detachably connected to form a die inlet (43) and a die outlet, and an upper supporting convex structure (44) and a lower supporting convex structure (45) that fit into a semicircular shape are provided between the upper die (41) and the lower die (42), and a rectangular gap is provided between the upper supporting convex structure (44) and the lower supporting convex structure (45); and an unequal width inclined surface is provided at the outlet of the extrusion die.

[0018] Controlling the extrusion wheel speed at 2-3r / min can avoid the problem of rapid grain growth caused by the increase of extrusion temperature due to excessive speed, and ensure that the grain size of the product is small.

[0019] Moreover, through the structural characteristics of the extrusion die, the flow direction of the copper melt after entering the extrusion die can be controlled, thereby ensuring that the copper melt is fully deformed and at the same time ensuring the uniformity of the copper fluid flow, so that the grains of the produced billet are small and uniform.

[0020] Furthermore, in step S1, a high-purity oxygen-free copper rod is prepared using an upward continuous casting method. The specific operation is: electrolytic copper is used as the production raw material, the raw material is put into a smelting furnace, an inert protective gas is introduced, and an upward continuous casting furnace is used to use an oxygen-free copper billet crystallizer to form the oxygen-free copper rod.

[0021] The 4N5 oxygen-free copper rod produced by the upward continuous casting method can ensure the accuracy of the copper rod, thereby ensuring the stability in the subsequent process and the accuracy of the final product. The use of anti-oxidation cooling device can protect the copper billet and ensure the reliability of the copper billet composition.

[0022] Furthermore, in step S6, a CNC machine tool is used to perform machining operations, including: rough disk surface, rough milling, chamfering, fine milling and fine disk surface, wherein the single milling cutting depth in rough disk surface, rough milling and chamfering is less than 0.2 mm, and the single cutting depth in fine milling and fine disk surface is 0.05 mm.

[0023] Furthermore, the present invention provides a magnetron sputtering method using a planar copper target, comprising:

[0024] Step 1: Combine a copper target and a backing plate to prepare a sputtering target, measure the flatness of the bottom surface of the backing plate, and perform flaw detection on the sputtering target;

[0025] Step 2: Roughly grind the qualified sputtering target and protect the non-pre-blasting area;

[0026] Step 3: Sandblast the pre-blasted area and measure the surface roughness after sandblasting;

[0027] Step 4: Fine grinding is performed on the non-pre-blasting area of ​​the qualified sputtering target. After grinding, the surface is cleaned to remove dust, and then the sputtering target is thoroughly cleaned to obtain a magnetron sputtering target.

[0028] Step 5: Install the sputtering target on the magnetron sputtering equipment and perform magnetron sputtering.

[0029] Furthermore, in step 1, the specific operation of combining the copper target with the backing plate is as follows:

[0030] a: Protect the non-bonding surface of the copper target and the backing plate, and place the copper target and the backing plate on the bonding table for preheating;

[0031] b: Use indium as a binder, spread indium evenly on the bonding surface and super indium the bonding surface of the copper target and the backing plate;

[0032] c: After the super indium coating is completed, place at least two copper wires on the backplane, evenly spread indium and cover the copper wires with indium, tighten the copper wires, and remove the oxide on the surface of the indium layer;

[0033] d: Turn the copper target over and slowly place it on the indium layer to fit it, and use the adjustment tool to measure and adjust the gap around it to meet the requirements of the drawing before pressing it;

[0034] e: After the sputtering target cools to 100°C, remove excess indium and protect the non-bonding surface.

[0035] The problem of poor surface flatness of the copper billet was solved by performing a single-pass low-deformation drawing operation on the copper billet.

[0036] The sputtering target is made by combining the copper target material with the back plate, so that the angle of the target material in the horizontal direction can be well controlled during the magnetron sputtering process, thereby being able to adapt to different ion beam injection angles, and by controlling the flatness of the back plate, subsequent processing processes are facilitated.

[0037] Indium is used as a binder, which has good thermal and electrical conductivity. Through super-indium operation, indium can be vibrated to the copper surface to form a thin metallization layer, making it easier for the copper target and the backplane to fit together. By setting copper wire, the thickness of the indium layer between the copper target and the backplane can be controlled to meet the requirements.

[0038] Furthermore, during the bonding process, the copper target and the back plate are heated to a temperature of 170° C.-180° C.

[0039] Furthermore, in step 3, white corundum sand is used for sandblasting operation, the sandblasting pressure is 0.6-0.8 MPa, the sandblasting speed is 25 mm / s, the number of sandblasting cycles is three, the swing frequency is 25 Hz, and the automatic translation speed is: 120 mm / s.

[0040] By setting the sandblasting parameters, the roughness of the sandblasting surface can be controlled to meet the required requirements.

[0041] Furthermore, in step 4, the cleaning operation after polishing is specifically as follows:

[0042] S1: Remove excess dust from the surface of the sputtering target by using an air knife;

[0043] S2: Use a dust-free cloth dipped in anhydrous ethanol to thoroughly clean the pre-sputtering surface of the sputtering target.

[0044] The beneficial effects achieved by the present invention are:

[0045] 1. Through repeated continuous extrusion and drawing operations, the equiaxed grains of the copper structure are compressed in the cross-sectional direction, resulting in grain refinement, and the copper structure is transformed from coarse equiaxed grains to multiple fine grains, so that the grain size of the prepared target material is less than 40μm, and the grains are fine and uniform.

[0046] 2. During the continuous extrusion process, the copper billet is cooled to room temperature through an anti-oxidation cooling circulation device, which protects the copper billet and ensures the reliability of the copper billet composition.

[0047] 3. The upper and lower convex structures that fit into each other in a semicircular shape are set on the upper and lower convex structures of the extrusion die to control the flow direction of the copper melt after entering the extrusion die, thereby ensuring that the copper melt is fully deformed and flows uniformly, so that the grains of the copper billet produced are small and uniform.

[0048] 4. The entire preparation process is simple and convenient, with low time and labor costs. Through the entire preparation process, micro-control of the target material composition, organization, and texture can be achieved, thereby realizing low-cost, high-reliability industrial continuous production.

[0049] 5. The copper target material prepared is used as the main body and combined with the back plate, so that the angle of the target material in the horizontal direction can be well controlled during the magnetron sputtering application process, thereby being able to adapt to different ion beam injection angles, and by controlling the flatness of the back plate, it is convenient for subsequent processes.

[0050] 6. In the process of bonding the copper target to the back plate, an indium groove is provided on the back plate, and indium is used as a bonding agent to make the bonding effect between the copper target and the back plate better.

[0051] 7. By performing super-indium operation on the backplane, a thin metallization layer can be formed on the backplane, making the copper target material fit better with the backplane.

[0052] 8. Arranging copper wire on the back plate can better control the thickness of the indium layer between the copper target and the back plate, and optimize its electrical and thermal conductivity.

[0053] 9. Through the process of flaw detection, sandblasting, grinding and comprehensive cleaning of the sputtering target, the quality and precision requirements of the copper target are guaranteed, and the stability of the magnetron sputtering process is guaranteed. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] In order to make the contents of the present invention more clearly understood, the present invention is further described in detail below based on specific embodiments in conjunction with the accompanying drawings.

[0055] Figure 1 This is a process flow chart for preparing a planar copper target embryo.

[0056] Figure 2 It is a schematic diagram of the extrusion die structure.

[0057] Figure 3 This is a metallographic diagram of the cross section of the end of a flat copper target.

[0058] Figure 4This is a metallographic diagram of the longitudinal section of the end of a flat copper target.

[0059] Figure 5 This is a metallographic diagram of the middle cross section of a flat copper target.

[0060] Figure 6 This is a metallographic diagram of the longitudinal section of the middle of a flat copper target.

[0061] Among them, 1 is an upper continuous casting furnace, 2 is a continuous extruder, 3 is a drawing device, 4 is a CNC machine tool, 43 is a mold entrance, 41 is an upper mold, 42 is a lower mold, 44 is an upper support protruding structure, and 45 is a lower support protruding structure. DETAILED DESCRIPTION

[0062] The technical solution of the present invention is further described below with reference to the accompanying drawings, but is not limited thereto. Any modification or equivalent replacement of the technical solution of the present invention that does not depart from the spirit and scope of the technical solution of the present invention should be included in the scope of protection of the present invention.

[0063] Example 1

[0064] like Figure 1 As shown, this embodiment provides a method for preparing a planar copper target, and the preparation method specifically includes the following steps:

[0065] Step S1: preparing a high-purity oxygen-free copper rod;

[0066] Step S2: continuously extruding the oxygen-free copper rod to form a billet, and performing anti-oxidation protection on the billet during the extrusion process;

[0067] Step S3: After the blank is cooled to room temperature, a single-pass low-deformation drawing operation is performed, wherein the drawing deformation is controlled to be 1.5%-3%, and the drawing deformation temperature is controlled to be 300° C.-500° C.;

[0068] Step S4: Repeat the above steps S2 and S3 at least twice;

[0069] Step S5: performing straightening operation on the blank;

[0070] Step S6: machining the blank to produce a copper target.

[0071] Among them, in step S1, the upward continuous casting method is used to prepare high-purity oxygen-free copper rods. The specific operations are: electrolytic copper with a purity greater than 99.995% is used as a production raw material, the working gas pressure is set to 0.01MPa, and the electrolytic copper is then put into a smelting furnace at a temperature of 1200°C, and nitrogen is introduced for anti-oxidation protection to prevent the electrolytic copper from being oxidized. Finally, an upward continuous casting oxygen-free copper billet crystallizer is used to form the oxygen-free copper billet, and the copper rod casting is achieved through a traction process to generate 4N5 oxygen-free copper rods with a diameter of 25-30mm. This method greatly improves production efficiency.

[0072] In step S2, a continuous extruder is used to complete the continuous extrusion process. The specific operation is: using oxygen-free copper rod as raw material, using a continuous extruder to continuously extrude the oxygen-free copper rod, so that the oxygen-free copper rod is input into the deformation area between the extrusion wheel and the cavity through the continuous extruder feed port, setting the extrusion wheel speed to 2-3r / min, and the oxygen-free copper rod is limited by the block block and flows into the extrusion mold cavity, and the copper rod is extruded by friction deformation heat, so that the copper rod is expanded to the entire cavity of the extrusion mold to obtain a copper billet; in addition, during the continuous extrusion process, an anti-oxidation cooling circulation device is used to protect the copper billet 1, and the copper billet is protected from oxidation by nitrogen, and the copper billet is gradually cooled to room temperature in combination with cooling water and a circulation pipeline.

[0073] Preferably, the continuous extruder is an MFCCE700 continuous extruder, comprising an extrusion wheel, a compacting wheel, a stop block, an extrusion positioning shaft and a cavity. A feed port is provided between the extrusion wheel and the compacting wheel, a deformation area is provided between the extrusion wheel and the cavity, the extrusion mold is placed in the cavity, a stop block is provided at the mold inlet 1, and the extrusion positioning shaft comprises an upper eccentric shaft and a lower eccentric shaft; a servo hydraulic system is provided outside the continuous extruder for real-time regulation of the distance between the extrusion wheel and the cavity, adjustment of the relative position between the upper eccentric shaft and the lower eccentric shaft, and control of the yield rate of the finished product.

[0074] During use, the raw material enters the deformation area through the feed port and flows into the extrusion die under the limiting action of the stop block. The raw material is extruded and expanded to the entire cavity by utilizing the friction deformation heat. The entire continuous extrusion process completes the metal plastic forming process in a closed environment and has anti-oxidation protection measures, basically realizing oxidation-free extrusion without generating extrusion residual. The material utilization rate is high, and high-quality production of copper billets can be achieved.

[0075] Preferably, the extrusion die is placed in a cavity, and includes an upper die 41 and a lower die 42. The upper die 41 and the lower die 42 are detachably connected by bolts, which facilitates the replacement of the die in the subsequent process. After the upper die 41 and the lower die 42 are connected, a die inlet 43 and a die outlet are formed. An upper support protrusion structure 44 and a lower support protrusion structure 45 that fit together into a semicircular shape are provided between the upper die 41 and the lower die 42 for diversion and diversion. A rectangular channel is provided in the half between the upper support protrusion structure 44 and the lower support protrusion structure 45 for allowing part of the copper to flow out of the channel. An unequal width inclined surface is provided at the outlet of the extrusion die, which facilitates the solution of the flatness and operability of the billet discharge molding while controlling the extrusion forming size of the sheet material, and copper billets of different specifications can be produced according to the different die diameters. The width of the produced copper billets is 203-400mm and the thickness is 18.5-355mm.

[0076] During use, the copper melt flows into the mold from the mold inlet, and continuously flows along the arc radius after encountering the semicircular raised structure 43. The copper melt flows to both sides and enters the cone-like cavity. The copper melt is compressed again to form a secondary change and deformation, and then enters the cone structure again to deform again. At the same time, a part of the copper fluid flows out from the rectangular gap between the semicircular raised structures, and finally merges with the cone after flowing to a certain distance, so as to ensure that the copper melt is fully deformed and flows evenly, thereby ensuring that fine grains are obtained.

[0077] In step S3, the copper billet is drawn and straightened by a drawing machine and a straightening machine respectively. The specific operations are as follows: a single-pass low-deformation drawing operation is performed on the copper billet using a drawing machine, and the drawing deformation is controlled to be 1.5%-3%, and the drawing deformation temperature is controlled to be 300℃-500℃, which can compress the equiaxed grains of the copper structure in the cross-sectional direction, thereby resulting in grain refinement and solving the problem of poor surface flatness of the copper billet; the drawn copper billet is then straightened by a straightening machine to make the copper billet size flatness ≤0.5mm.

[0078] In step S4, the copper billet is machined by a CNC machine tool, and the machining process includes rough disk surface, rough milling, chamfering, fine milling and fine disk surface. The specific operation is: use a CNC machine tool to perform rough disk surface, rough milling, fine milling and fine disk surface processes in sequence, set the cutting amount of a single milling to be less than 0.2mm, use a disc cutter to perform three disc surfaces, and then use a milling cutter with a diameter of 12mm to mill the shape, complete rough milling, and then use an R3 angle cutter to chamfer the shape, and then set the cutting amount of a single milling to be 0.05mm, use a milling cutter with a diameter of 12mm to mill the shape, complete the fine milling operation, and use a disc cutter to perform a disc surface to complete the machining operation. After the machining is completed, the size of the copper billet is processed from 3430 (0+3) mm in length, 204 (0+1) mm in width, and 25.2 (0+0.2) mm in height to 3430 mm in length, 200 mm in width, and 24.5 mm in height to obtain a flat copper target blank.

[0079] Example 2

[0080] This embodiment provides a magnetron sputtering method for preparing a copper target material using the preparation method described in Example 1, comprising:

[0081] Step 1: combining a copper target material and a backing plate to obtain a combination of the copper target material and the backing plate, i.e., a sputtering target material, then measuring the flatness of the bottom surface of the backing plate, and performing flaw detection on the sputtering target material;

[0082] Step 2: Roughly grind the qualified sputtering target and protect the non-pre-blasting area;

[0083] Step 3: Sandblast the pre-blasted area and measure the surface roughness after sandblasting;

[0084] Step 4: Fine grinding is performed on the non-pre-blasting area of ​​the qualified sputtering target. After grinding, the surface is cleaned to remove dust, and then the sputtering target is thoroughly cleaned to obtain a magnetron sputtering target.

[0085] Step 5: Install the sputtering target on the magnetron sputtering equipment and perform magnetron sputtering.

[0086] Among them, in step 1, the copper target material and the back plate are combined by welding, and the specific operation is: first, use protective tape to protect the non-welding surface of the copper target material and the back plate, and make an indium groove on the edge of the welding surface of the back plate, place the copper target material and the back plate on the bonding table for preheating, and set the welding temperature to 170℃-180℃; after the copper target material and the back plate are heated, use a stainless steel spoon to sprinkle 3-4 flat spoons of indium on the bonding surface, and brush it from beginning to end with a stainless steel brush, and then use an ultrasonic vibrating rod (also known as a super indium gun) to super indium the bonding surface of the copper target material and the back plate 3-4 times; observe the state of indium during the super indium process; after the super indium is completed, use a spatula to scrape the super indium part to confirm whether there is any copper plate leakage or abnormal color, and observe the super indium of the bonding surface of the copper target material and the back plate. In this case, two copper wires are placed parallel to the backboard, with the end at one end 1 / 3 of the distance from the backboard, and the end at the other end 1 / 4 of the distance from the backboard, leaving 20 cm at both ends. Use a stainless steel spoon to evenly sprinkle indium on the surface so that the indium covers the copper wire, tighten the copper wire, use a scraper parallel to the surface of the indium layer, move it back parallel, gently lift the oxide layer and impurities and move them to another place, after removing the oxide, turn the copper target over and slowly place it on the backboard to fit, use the adjustment tool to measure and adjust the gap around the copper target and the backboard to meet the requirements of the drawing, then press it to make the sputtering target, then cut off and remove the excess copper wire, turn off the power, cool the sputtering target to 100°C, remove the excess indium around it with a tool, and remove the copper target and backboard protective tape at the same time.

[0087] After removing the protective tape on the non-welded surface of the sputtering target, pull it to the marble platform, measure the flatness of the bottom surface of the sputtering target, and judge it according to the standards of the work requirements. If it fails, calibrate it; the sputtering target with qualified flatness is inspected by water immersion ultrasonic testing, and the inspection results are judged according to the inspection standards; the sputtering target that passes the inspection is dried, and the drying temperature is set at 80℃ and the drying time is 1 hour.

[0088] Preferably, the back plate is derived from the magnetron sputtering equipment required to install the copper target, and is used in a set with the equipment. The back plate can be installed in the corresponding base on the magnetron sputtering equipment. By combining the copper target with the back plate, the magnetron sputtering process is made faster, and by cooperating with the base on the magnetron sputtering equipment, the angle of the copper target can be adjusted accordingly to cope with different incident angles of the ion beam. By combining the copper target with the back plate, the copper target can be protected to a certain extent, preventing the copper target from breaking due to uneven heating, and effectively ensuring the quality and stability of the film plated in magnetron sputtering.

[0089] Preferably, an indium groove can be added to the middle area of ​​the back plate, and the number of copper wires can be increased or the position of the copper wires can be adjusted accordingly; the indium groove makes the indium between the copper target and the back plate more sufficient, and the fitting effect between the two is increased. By adjusting the number and position of the copper wires, the copper target can be placed flat, and the uniformity of the indium layer thickness can be ensured.

[0090] In step 2, after the qualified sputtering target is dried, the robot is pre-programmed and the sputtering target is rough-grinded using automatic grinding equipment to remove surface oxides and excess indium points to avoid affecting sandblasting. The requirements for rough grinding are: holes and surfaces: bright, no oxidation (blackening, discoloration), and no obvious marks; waterway intersections: no scratches or collapsed corners are allowed; rough grinding can avoid delamination after sandblasting, and the non-pre-sandblasting area is protected after grinding.

[0091] In step 3, the pre-blasting area of ​​the sputtering target after rough grinding is sandblasted. During the sandblasting process, 24-mesh white corundum sand or stainless steel sand is used for automatic sandblasting. The sandblasting pressure is set to: 0.6-0.8 MPa, sandblasting speed: 25 mm / s, sandblasting cycle number: 3 times, swing frequency: 25 Hz, automatic translation speed: 120 mm / s; after sandblasting, the surface roughness of the sandblasting area is measured using a roughness detection device to determine whether the roughness meets the standard.

[0092] In step 4, the non-sandblasting area of ​​the sputtering target with qualified roughness is fine-polished. The program is pre-set by the robot, and the non-sandblasting area of ​​the sputtering target is fine-polished using automatic polishing equipment. The surface and surrounding areas of the sputtering target are required to be bright and have no color difference, uniform color, no scratches, and a roughness of less than Ra0.8. Scratches and collapsed angles are not allowed. After polishing, an air knife is used to clean and remove excess dust on the surface of the sputtering target. Manual intervention is performed using a dust-free cloth dipped in anhydrous ethanol to comprehensively clean the sputtering target and the pre-sputtering surface to ensure that the sputtering target is not oxidized and then dried. After drying, it is installed on the magnetron sputtering equipment for the magnetron sputtering process.

[0093] Example 3

[0094] This comparative example provides a method for preparing a planar copper target. In step S2 of the preparation method, the rotation speed of the extrusion wheel is 4 r / min, and the rest is the same as in Example 1.

[0095] Example 4

[0096] This comparative example provides a method for preparing a planar copper target. In step S2 of the preparation method, the rotation speed of the extrusion wheel is 6 r / min, and the rest is the same as in Example 1.

[0097] Example 5

[0098] This comparative example provides a method for preparing a planar copper target. In step S2 of the preparation method, the rotation speed of the extrusion wheel is 8 r / min, and the rest is the same as in Example 1.

[0099] Example 6

[0100] This comparative example provides a method for preparing a planar copper target. In step S2 of the preparation method, the rotation speed of the extrusion wheel is 10 r / min, and the rest is the same as in Example 1.

[0101] Test results

[0102] The grain size of the planar copper target prepared by the preparation method described in the above embodiment was detected, and the obtained data were summarized in the following table:

[0103] Grain size (μm) Example 1 35 Example 3 45 Example 4 65 Example 5 78 Example 6 90

[0104] Based on the above test results, it can be seen that the copper target material prepared by the preparation method of the planar copper target material described in the present invention has a grain size of less than 40 μm, which has the advantages of small and uniform grain size. It also shows that controlling the speed of the extrusion wheel in the extrusion device within a certain range is beneficial to the control of the grain size. When the extrusion wheel speed is too large, the grain size will grow due to the increase in extrusion temperature, thereby affecting the quality of the copper target material.

[0105] The present invention uses continuous extrusion and drawing operations, combined with the design of the mold structure and the control of the extrusion wheel speed, to enable the planar copper target to have the advantages of small and uniform grain size and small grain boundary orientation difference. In addition, the preparation process of the planar copper target described in the present invention is simple, greatly shortens the production cycle, and reduces time and labor costs. The entire preparation process can achieve micro-control of the target material composition, organization, and texture, thereby realizing low-cost, high-reliability industrial continuous production.

[0106] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention's description and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A method for preparing a planar copper target, characterized in that: include: Step S1: preparing a high-purity oxygen-free copper rod; Step S2: continuously extruding the oxygen-free copper rod to form a billet, and performing anti-oxidation protection on the billet during the extrusion process; Step S3: After the blank is cooled to room temperature, a single-pass low-deformation drawing operation is performed, wherein the drawing deformation is controlled to be 1.5%-3%, and the drawing deformation temperature is controlled to be 300° C.-500° C.; Step S4: Repeat the above steps S2 and S3 at least twice; Step S5: performing straightening operation on the blank; Step S6: machining the blank to produce a copper target; In step S2, a continuous extrusion operation is performed using a continuous extruder, and an anti-oxidation cooling circulation device is used to cool the billet to room temperature; The continuous extruder is provided with an extrusion wheel and an extrusion die, and the speed of the extrusion wheel is 2-3r / min; The extrusion die comprises an upper die (41) and a lower die (42), wherein the upper die (41) and the lower die (42) are detachably connected to form a die inlet (43) and a die outlet, and an upper supporting convex structure (44) and a lower supporting convex structure (45) that fit into a semicircular shape are provided between the upper die (41) and the lower die (42), and a rectangular gap is provided between the upper supporting convex structure (44) and the lower supporting convex structure (45); and an unequal width inclined surface is provided at the outlet of the extrusion die.

2. The method for preparing a planar copper target according to claim 1, wherein: In step S1, a high-purity oxygen-free copper rod is prepared by an upward continuous casting method. The specific operation is: electrolytic copper is used as the production raw material, the raw material is put into a smelting furnace, an inert protective gas is introduced, and the oxygen-free copper rod is formed by using an upward continuous casting furnace and an oxygen-free copper billet crystallizer.

3. The method for preparing a planar copper target according to claim 1, wherein: In step S6, a CNC machine tool is used to perform machining operations, including roughing, rough milling, chamfering, fine milling and fine discing, wherein the single milling depth in roughing, rough milling and chamfering is less than 0.2 mm, and the single cutting depth in fine milling and fine discing is 0.05 mm.

4. A magnetron sputtering method using the planar copper target according to any one of claims 1 to 3, characterized in that: include: Step 1: Combine the copper target and the backing plate to obtain a sputtering target, measure the flatness of the bottom surface of the backing plate, and perform flaw detection on the sputtering target; Step 2: rough grinding the qualified sputtering target and protecting the non-pre-sandblasting area on the sputtering target; Step 3: Sandblast the pre-blasted area and measure the surface roughness after sandblasting; Step 4: Finely grind the non-pre-blasted areas of the sputtering target that meet the surface roughness requirements. After grinding, clean the surface to remove dust, and then thoroughly clean the sputtering target. Step 5: Install the cleaned sputtering target on the magnetron sputtering equipment and perform magnetron sputtering.

5. The magnetron sputtering method according to claim 4, characterized in that In step 1, the specific operation of welding the copper target and the backing plate is as follows: a: Protect the non-bonding surface of the copper target and the backing plate, and place the copper target and the backing plate on the bonding table for preheating; b: Use indium as a binder, spread indium evenly on the bonding surface and super indium the bonding surface of the copper target and the backing plate; c: After the super indium coating is completed, place at least two copper wires on the backplane, evenly spread indium and cover the copper wires with indium, tighten the copper wires, and remove the oxide on the surface of the indium layer; d: Turn the copper target over and slowly place it on the indium layer on the bonding surface, and use the adjustment tool to measure and adjust the gap around the copper target and the back plate to meet the requirements of the drawing before pressing; e: After the sputtering target cools to 100°C, remove excess indium and protect the non-bonding surface.

6. The magnetron sputtering method according to claim 5, characterized in that: During the bonding process, the copper target and the back plate are heated to a temperature of 170° C.-180° C.

7. The magnetron sputtering method according to claim 4, characterized in that: In step 3, white corundum sand is used for sandblasting operation, the sandblasting pressure is 0.6-0.8 MPa, the sandblasting speed is 25 mm / s, the number of sandblasting cycles is three, the swing frequency is 25 Hz, and the automatic translation speed is: 120 mm / s.

8. The magnetron sputtering method according to claim 4, characterized in that: In step 4, the cleaning operation after polishing is as follows: S1: Remove excess dust from the surface of the sputtering target by using an air knife; S2: Use a dust-free cloth dipped in anhydrous ethanol to thoroughly clean the pre-sputtering surface of the sputtering target.

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