Production process of high-hardness plane sputtering copper target material

Abstract

The invention relates to the field of target material production, and provides a production process of a high-hardness plane sputtering copper target material, which comprises the following steps: heating and melting a high-purity electrolytic copper plate through a power frequency induction heating furnace, crystallizing the molten solution through a crystallizer to form a copper rod with the diameter of 20mm, and coiling; the method comprises the following steps: extruding and thickening a copper rod with the diameter of 20 mm into a copper rod with the diameter of 25 mm to realize primary crushing of crystal grains in the copper rod, extruding and thickening the copper rod with the diameter of 25 mm into a copper rod with the diameter of 30 mm to realize secondary crushing of crystal grains in the copper rod, infinitely extending and extruding the copper rod with the diameter of 30 mm into a copper bar, and gradually prolonging the copper bar through continuous feeding. The preparation method comprises the following steps of: forming a strip-shaped regular copper plate, correcting the copper plate through a fixed-length drawing machine, sawing the copper plate, straightening to completely remove internal stress, and finally performing flaw detection, machining and welding with a back plate to obtain the sputtering copper target material. The crystal grains are uniformly controlled, the energy consumption is low, and the yield is high.

Description

Technical Field

[0001] The invention relates to the field of target material production, and in particular to a production process of a high-hardness planar sputtering copper target material. Background Art

[0002] Sputtering targets can be divided into planar targets, multi-arc targets, and rotating targets according to their shapes. Planar targets include planar copper targets, which require copper bars to be made first.

[0003] Traditional flat sputtering copper busbar production method: smelting - forging - rolling - heat treatment - machine tool processing

[0004] Since the sputtering copper target has technical requirements for its oxygen content, which must be ≤10ppm, vacuum melting equipment or high-end down-drawing equipment must be used to cast copper ingots during smelting;

[0005] Disadvantages of traditional smelting:

[0006] Smelting uses electricity or natural gas, the smelting process is relatively long, the energy consumption is high, the temperature requirement is relatively high, the process is complex, and the smelting safety risk is relatively high;

[0007] The efficiency is low. The vacuum evacuation time and the heat preservation time of vacuum melting are relatively long, and the efficiency is relatively slow. The lower ingot also has a length limit, and the material conversion and quantity control are also relatively cumbersome.

[0008] Through the forging process of upsetting and drawing and the intermediate heat treatment production mode, the copper ingot is forged into a square embryo of the required size, and the grains are initially broken;

[0009] Disadvantages of forging:

[0010] In the early stage of the forging process, the ingot needs to be heated at high temperature, generally at 800 degrees. The black oxide scale will fall off when the copper ingot is forged at high temperature. If it is not cleaned properly, it is easy to embed into the copper ingot and form internal defects.

[0011] Copper targets are more likely to crack during forging, increasing the risk of finished products.

[0012] When copper target forging wants to reach the target material use level, hot section and cold forging need to be coordinated, annealing and water cooling are intertwined, and the process control is relatively complicated;

[0013] The forged copper ingot is hot-rolled and cold-rolled in a rolling mill to reach the size designed by the process, and then the matching type variables and temperature settings are set to meet the grain control requirements;

[0014] Disadvantages of rolling:

[0015] The rolling process requires multiple deformations, and the deformation amount generally does not exceed 30%. This deformation will cause the surface grains to be more broken than the core. Especially in the cold rolling stage, the risk of cracking is relatively high. The deformation amount will be designed to be smaller, and the grain differentiation will be more obvious, so the hardness will be more differentiated due to the uneven grain size.

[0016] After rolling, the grains are in a fibrous structure and need to be heat treated to form grains and remove internal stress. During the internal stress removal process, the product will become softer as a whole, with a hardness of less than 70HV, and poor overall strength, which affects normal use.

[0017] There is a risk of twins inside the copper target after rolling. The twins will absorb energy and crystallize again during use, affecting the sputtering rate.

[0018] Finally, the target material is processed by machine tools to the size required by the customer's drawings.

[0019] Finally, the target material is welded to the customer's back plate through special materials and sent to the client for use after processing;

[0020] In summary, the above-mentioned processes have the disadvantages of high cost, complex process technology, and uneven grains leading to large differences in hardness, which affects the mechanical properties of the material. Summary of the invention

[0021] In view of this, the purpose of the present invention is to provide a production process of a high-hardness planar sputtering copper target material to solve the problems in the background technology.

[0022] Based on the above purpose, the present invention provides a production process of a high-hardness planar sputtering copper target, comprising the following steps:

[0023] Step 1, preheating the prepared high-purity ≥4N 1# electrolytic copper plate;

[0024] Step 2: Place the preheated electrolytic copper plate into the smelting chamber of the power frequency induction heating furnace, adjust the temperature to 1200±20℃ for heating, and after the electrolytic copper plate melts, the solution enters the insulation chamber of the power frequency induction heating furnace:

[0025] Step 3: insert the crystallizer into the solution in the insulation chamber, and the solution enters the crystallizer and solidifies into a copper rod and is continuously discharged outward;

[0026] Step 4: Connect one end of the pulled copper rod with a diameter of 20 mm to the closing machine for pulling and closing;

[0027] Step 5: The copper rod with a diameter of 20 mm is extruded into a copper rod with a diameter of 25 mm, and the grains inside the copper rod are initially crushed by extrusion, deformation and thickening;

[0028] Step 6: Continue to extrude the copper rod with a diameter of 25 mm to make it thicker into a copper rod with a diameter of 30 mm, and perform a second extrusion deformation to crush the grains for a second time;

[0029] Step 7: infinitely stretch and extrude the copper rod with a diameter of 30 mm to form a long regular copper plate, and then roll it up;

[0030] Step 8: After the coiling is completed, it is transferred to the fixed-length drawing machine, and the drawing die is loaded to correct the size of the copper plate, and the surface reserve is used for subsequent machine tool processing;

[0031] Step nine, sawing the copper plate, and straightening the sawed copper plate through a multi-rod stress relief straightening machine to completely remove the internal stress;

[0032] Step 10: After straightening, use a non-destructive flaw detector to detect whether there are defects inside the copper plate;

[0033] Step eleven, transferring the qualified copper plate to the machining center for processing, welding the machined plate and the back plate to obtain a sputtering copper target.

[0034] Preferably, in step 5, the copper rod with a diameter of 20 mm is extruded and thickened into a copper rod with a diameter of 25 mm by an extruder with an extrusion wheel having a nominal diameter of Φ550 mm to Φ600 mm.

[0035] Preferably, in step seven, the copper rod with a diameter of 30 mm is loaded into an extrusion die of an extruder with an extrusion wheel having a nominal diameter of ≥ Φ700 mm for infinite extension extrusion.

[0036] Preferably, in step seven, the extrusion die of the extruder with a nominal diameter of the extrusion wheel ≥Φ700mm is preheated in advance to a temperature of 600°C±10°C. The copper rod generates heat through friction between the rollers and enters the extrusion die. The copper bar is formed by the action of the extrusion die. The copper bar is gradually extended by the continuous entry of subsequent materials to form a long regular copper plate.

[0037] Preferably, in step seven, the copper is rapidly cooled after being discharged from the die mouth of the extrusion die, and nitrogen is used for rapid cooling at a distance of 1 meter from the die.

[0038] Preferably, the upper ends of the solutions in the smelting chamber and the holding chamber of the industrial frequency induction heating furnace need to be covered with charcoal combustion to isolate oxygen.

[0039] Preferably, in the step eight, the drawing mouth of the fixed-length drawing machine is preheated using a ring-shaped high-frequency coil, the frequency of the high-frequency coil is ≥4000HZ, and the preheating temperature is ≤340°C, for preliminary stress removal.

[0040] The beneficial effects of the present invention are as follows: the present invention first heats and melts the high-purity electrolytic copper plate through an industrial frequency induction heating furnace, then crystallizes the molten solution through a crystallizer to form a copper rod with a diameter of 20 mm for closing, then extrude and thicken the copper rod with a diameter of 20 mm into a copper rod with a diameter of 25 mm to achieve the primary crushing of the crystal grains inside the copper rod, then extrude and thicken the copper rod with a diameter of 25 mm into a copper rod with a diameter of 30 mm to achieve the secondary crushing of the crystal grains inside the copper rod, at this time, the copper rod grains are ≤25um and the grain size distribution is uniform, then the copper rod with a diameter of 30 mm is infinitely extended and extruded into a copper bar, the copper bar is gradually extended by continuous feeding to form a long and regular copper plate, the copper bar is quickly cooled after exiting the mold mouth, thereby reducing the time for the crystal grain growth, thereby effectively controlling the size of the crystal grain, and the copper plate Then it is corrected by a fixed-length drawing machine. The drawing mouth of the fixed-length drawing machine is preheated by a high-frequency coil to remove stress. A surface margin is reserved for subsequent machine tool processing. The copper plate is then sawed and straightened by a multi-rod stress relief straightening machine to completely remove internal stress. Finally, it is subjected to flaw detection, machining, and welding with a back plate to obtain a sputtering copper target. The grain control of the present invention is uniform, the average grain difference is less than 10um, and the maximum grain is less than 150um; the hardness inside and outside is uniform, the process setting determines the uniformity of the grain, and the uniformity of the grain determines the uniform hardness, with small differences; in the entire extrusion process, except for the heat required for preheating the mold, no separate heat source is required for the rest, and the energy consumption is low; the entire equipment is continuously fed in by copper rods to produce copper bars, can be produced continuously, has a large output, and can reach a production capacity of more than 2 tons per hour. DETAILED DESCRIPTION

[0041] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments.

[0042] It should be noted that, unless otherwise defined, the technical terms or scientific terms used in the present invention should be understood by people with ordinary skills in the field to which the present invention belongs. The "first", "second" and similar words used in the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. "Include" or "comprise" and similar words mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0043] This embodiment provides a production process for a high-hardness planar sputtering copper target, comprising the following steps:

[0044] S1, preheating the prepared high-purity ≥4N 1# electrolytic copper plate;

[0045] S2, put the preheated electrolytic copper plate into the melting chamber of the power frequency induction heating furnace, adjust the temperature to 1200±20℃ for heating, after the electrolytic copper plate melts, the solution enters the insulation chamber of the power frequency induction heating furnace, the upper ends of the solutions in the melting chamber and the insulation chamber of the power frequency induction heating furnace need to be covered with charcoal burning to isolate oxygen, the melting chamber and the insulation chamber of the power frequency induction heating furnace are connected through a connecting vessel, and the connection is located in the middle of the melting chamber and the insulation chamber, so that a higher purity solution can enter the insulation chamber. According to the density principle, impurities with low density will float on the upper end, and impurities with high density will be deposited at the bottom, and the solution in the middle part has higher purity;

[0046] S3, inserting the crystallizer into the solution in the insulation chamber, the solution enters the crystallizer and solidifies into a copper rod and is continuously discharged outward, and the crystallizer is a D20 crystallizer;

[0047] S4, connect one end of the pulled copper rod with a diameter of 20 mm to the closing machine for pulling and closing, and each plate weighs 5 tons;

[0048] S5, a copper rod with a diameter of 20 mm is extruded and thickened into a copper rod with a diameter of 25 mm by an extruder with an extrusion wheel having a nominal diameter of Φ550 mm to Φ600 mm, and the grains inside the copper rod are initially crushed by extrusion deformation and thickening, and the extruder is a MFCCE600 extruder;

[0049] S6, the copper rod with a diameter of 25 mm is further extruded and thickened into a copper rod with a diameter of 30 mm, and the grains are crushed for the second time through the second extrusion deformation. At this time, the grains of the copper rod after deformation are ≤25um, and the grain size distribution is uniform. The extruder is an MFCCE600 extruder;

[0050] S7, a copper rod with a diameter of 30 mm is loaded into an extrusion die of an extruder with an extrusion wheel with a nominal diameter of ≥Φ700 mm for infinite extension and extrusion. The extruder is an MFCCE700 extruder. The extrusion die of the extruder with an extrusion wheel with a nominal diameter of ≥Φ700 mm is preheated in advance to a temperature of 600°C±10°C. The copper rod generates heat through friction between the rollers and enters the extrusion die. A copper bar is formed through the action of the extrusion die. The copper bar is gradually extended by the continuous entry of subsequent materials to form a long regular copper plate. The copper bar is rapidly cooled after exiting the die mouth of the extrusion die. Nitrogen is used for rapid cooling at a distance of 1 meter from the die, and then rolled;

[0051] S8, after winding, it is transferred to the fixed-length drawing machine, and the drawing die is loaded to correct the size of the copper plate. The drawing die size is 95-97% of the extrusion die size (length and width). The drawing mouth of the fixed-length drawing machine is preheated with a ring-shaped high-frequency coil. The high-frequency coil frequency is ≥4000HZ, and the preheating temperature is ≤340℃. It is used to initially remove stress to facilitate the plate to pass through the drawing die mouth better. This process is used as a correction size, and the surface reserves a margin for subsequent machine tool processing;

[0052] S9, sawing the copper plate, and straightening the sawed copper plate through a multi-roller stress relief straightening machine to completely remove the internal stress;

[0053] S10, after straightening, use a non-destructive flaw detector to detect flaws. The probe M of the non-destructive flaw detector is ≥ 10M to detect whether there are defects inside the copper plate;

[0054] S11, transferring the qualified copper plate to the machining center for machining, machining the upper and lower surfaces and the surroundings, welding the machined plate and the back plate to obtain a sputtering copper target.

[0055] In this embodiment, the grains are uniformly controlled, the average grain difference is less than 10um, and the maximum grain is less than 150um; the hardness inside and outside is uniform, the process setting determines the uniformity of the grains, and the uniformity of the grains determines the uniform hardness with small differences; during the entire extrusion process, except for the heat required for preheating the mold, no separate heat source is required for other processes, and the energy consumption is low; the entire equipment is continuously fed by copper rods to produce copper bars, and can be produced continuously with a large output, which can reach a production capacity of more than 2 tons per hour.

[0056] It should be understood by those skilled in the art that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of the present invention is limited to these examples; under the concept of the present invention, the technical features in the above embodiments or different embodiments may also be combined, the steps may be implemented in any order, and there are many other variations of the different aspects of the present invention as described above, which are not provided in detail for the sake of simplicity. Any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention shall be included in the scope of protection of the present invention.

Claims

1. A production process for a high-hardness planar sputtering copper target, characterized in that: The following steps are included: Step 1, preheating the prepared high-purity ≥4N 1# electrolytic copper plate; Step 2: Place the preheated electrolytic copper plate into the smelting chamber of the power frequency induction heating furnace, adjust the temperature to 1200±20℃ for heating, and after the electrolytic copper plate melts, the solution enters the insulation chamber of the power frequency induction heating furnace: Step 3: insert the crystallizer into the solution in the insulation chamber, and the solution enters the crystallizer and solidifies into a copper rod and is continuously discharged outward; Step 4: Connect one end of the pulled copper rod with a diameter of 20 mm to the closing machine for pulling and closing; Step 5: The copper rod with a diameter of 20 mm is extruded into a copper rod with a diameter of 25 mm, and the grains inside the copper rod are initially crushed by extrusion, deformation and thickening; Step 6: Continue to extrude the copper rod with a diameter of 25 mm to make it thicker into a copper rod with a diameter of 30 mm, and perform a second extrusion deformation to crush the grains for a second time; Step 7: infinitely stretch and extrude the copper rod with a diameter of 30 mm to form a long regular copper plate, and then roll it up; Step 8: After the coiling is completed, it is transferred to the fixed-length drawing machine, and the drawing die is loaded to correct the size of the copper plate, and the surface reserve is used for subsequent machine tool processing; Step nine, sawing the copper plate, and straightening the sawed copper plate through a multi-rod stress relief straightening machine to completely remove the internal stress; Step 10: After straightening, use a non-destructive flaw detector to detect whether there are defects inside the copper plate; Step eleven, transferring the qualified copper plate to the machining center for processing, welding the machined plate and the back plate to obtain a sputtering copper target.

2. The production process of a high-hardness planar sputtering copper target according to claim 1, characterized in that: In the step 5, the copper rod with a diameter of 20 mm is extruded and thickened into a copper rod with a diameter of 25 mm by an extruder with an extrusion wheel having a nominal diameter of Φ550 mm to Φ600 mm.

3. The production process of a high hardness planar sputtering copper target according to claim 2, characterized in that: In the step 7, the copper rod with a diameter of 30 mm is placed in an extrusion die of an extruder with an extrusion wheel with a nominal diameter of ≥ Φ700 mm for infinite extension and extrusion.

4. The production process of a high-hardness planar sputtering copper target according to claim 3, characterized in that: In the step 7, the extrusion die of the extruder with an extrusion wheel nominal diameter ≥ Φ700mm is preheated in advance to a temperature of 600°C ± 10°C. The copper rod generates heat through friction between the rollers and enters the extrusion die. The copper bar is formed by the action of the extrusion die. The copper bar is gradually extended by the continuous entry of subsequent materials to form a long regular copper plate.

5. The production process of a high-hardness planar sputtering copper target according to claim 4, characterized in that: In the step 7, the copper is rapidly cooled after being discharged from the die mouth of the extrusion die, and nitrogen is used for rapid cooling at a distance of 1 meter from the die.

6. The production process of a high-hardness planar sputtering copper target according to claim 1, characterized in that: The upper ends of the solutions in the smelting chamber and the holding chamber of the industrial frequency induction heating furnace need to be covered with charcoal combustion to isolate oxygen.

7. The production process of a high-hardness planar sputtering copper target according to claim 1, characterized in that: In the step eight, the drawing mouth of the fixed-length drawing machine is preheated using a ring-shaped high-frequency coil, the high-frequency coil frequency is ≥4000HZ, and the preheating temperature is ≤340°C, for preliminary stress removal.