Manufacturing of copper targets for thin-film coating technology by sputtering from a hot extrusion process

Abstract

To provide a copper sputtering target having a crystal grain size of less than 20 microns.SOLUTION: The production of a copper sputtering target starts from the dissolution and casting process of copper having at least 99.99% of purity and copper having an oxygen content not beyond 5 ppm. Then, a hot extrusion process and a cold drawing process form a copper ingot. The hot extrusion process controls following variables so that the grain size of copper does not exceed 100 microns: 1) an extrusion ratio, 2) an ingot temperature, and 3) an extrusion rate.SELECTED DRAWING: Figure 7

Description

Technical Field

[0001] Related Art The present invention is in the field of metal science and technology in the field of copper metallurgy for thin film coating by sputtering method from hot extrusion process.

Background Art

[0002] Currently, most coatings use chemical methods such as electroplating. However, this method has the disadvantage of low coating quality and also has environmental problems, so it has been replaced by research and development of new coating technologies such as vacuum coating. Vacuum coating is performed only in a vacuum and does not use chemicals that cause environmental problems in the coating process. In vacuum coating, it is also possible to form a very thin coating known as a "thin film". A "thin film" is a film with a thickness of 5 microns or less. Thin film coating in a vacuum can be divided into two types: thin film coating by a chemical process and thin film coating by a physical process. 1. Chemical vapor deposition process (CVD) is a chemical coating of gas, and the chemical reaction results in a new coating of the substrate material such as plasma CVD and laser CVD methods. 2. Physical vapor deposition process (PVD) is a process in which coating atoms are removed from the surface and these diffuse or scatter onto the surface of the substrate material by evaporation and sputtering methods, etc.

[0003] Sputtering technology is one of the vacuum film coating technologies optimal for research and development of some types of film products. In this process, various film coatings such as films, metals, alloys, glasses, ceramics, semiconductor films, etc. are used. The thickness of the film can be accurately controlled and the properties of the film can be adjusted. Industries using sputtering technology such as microelectronics, semiconductors, films, conductors and film resistors, hard disk drives, automotive glass, optical fiber buildings, solar power generation TV screens, and mobile screens

[0004] The sputtering process begins by creating an atmosphere in the coating chamber by absorbing air bubbles from the coating. The pressure is 1x10 -6 The pressure is controlled to not exceed milligrams, and then an inert gas such as argon is added until the pressure is suitable for coating. Next, the coating is initiated by using a magnetic field to form argon gas ions. With an electric field, the ions collide with the target coating, causing the coating particles on the target surface to scatter onto the workpiece surface, forming a thin film as needed.

[0005] Previously, in the 1958 sputtering process, aluminum (Al) metal was used as the target material for the semiconductor surface layer (see U.S. Patent No. 5,598,285, Liquid crystal display device). While aluminum's resistance is not the lowest, it is used due to technical limitations.

[0006] However, in IBM's development in the 1980s, copper (Cu) and silver (Ag) were used as target metals. This was because both of these metals have much lower resistance than aluminum and exhibit superior electromigration resistance (Handbook of Thin Film Deposition, pp. 193-195).

[0007] The quality of a thin film varies depending on the operating conditions of the sputtering machine, such as the atmospheric pressure inside the chamber, the number of gas ions hitting the target material, and the type of gas used. It also depends on the properties of the target material. The properties of the target material directly affect the quality during sputtering, as follows: 1. Purification of the target material 2. Amount of dielectric material: Oxide (Al2O3 for Al targets, CuO for Cu targets). 3. Porosity and void volume due to gas during sputtering. 4. Grain size of the target material 5. Surface roughness of the target material 6. Mechanical strength or hardness of the target material.

[0008] To date, numerous studies have been conducted on material properties, manufacturing methods, and manufacturing conditions that affect the properties of target materials. These studies can be summarized as follows:

[0009] Patent: U.S. Patent Application Publication No. 2000 / 6139701 (Applied Materials): Copper targets with a hardness exceeding 45 Rockwell will have less splating or lower hardness than softer copper targets. The same effect is observed in high-hardness copper target tests up to 75 Rockwell. As hardness increased, splating decreased. To control hardness, the grain size (copper grain size) must be less than 50 microns (more preferably less than 25 microns). Hardness increases when the grain size is small due to forming techniques such as forging, rolling, and other processes. On the other hand, copper sputtering target materials with a large grain size are affected by increased surface roughness and decreased strength.

[0010] Patent: U.S. Patent Application Publication No. 2004 / 6746553 (Honeywell International Inc.): The quality of thin films formed on a substrate by sputtering depends on surface roughness. Any protrusions from the target surface cause abnormal discharges during sputtering. This is sometimes called micro-arking, where large particles (macroparticles) are scattered from the target surface and adhere to the substrate. Large particles within the film layer can cause short circuits in semiconductor devices. The adhesion of large particles is called "particles" or "splats." This study revealed that surface roughness is related to the grain size of the target. When the grain size of the target is small and finely varied, the surface becomes smoother. Therefore, the "particle" problem can also be prevented by reducing the grain size of the target. The quality of thin films produced by targets with small grain sizes is superior to that of targets with large grain sizes. This study investigates the reduction and variation in grain size when forming target materials using a forging process.

[0011] Patent: JP 2010-065252 (Mitsubishi Material Corp): The copper target material must have a copper purity of at least 99.99%, and in the multi-axis forging process, the grain size must be less than 20 microns.

[0012] Patent: JP-A11-158614: Conventional copper targets have an average grain size of less than 80 microns, resulting in a reduction in problems of coarse clusters and abnormal discharge. The resulting smaller grain size is due to the recrystallization mechanism in the manufacturing process of the copper target.

[0013] Patent: U.S. Patent Application Publication No. 2011 / 0139615 (Hitachi Cable Ltd): As a result of larger grain size, surface roughness increases, and as a result of smaller grain size, surface roughness decreases. Increasing the forming amount in the cold rolling process results in smaller grain size. The reduction in cold working in the cold rolling process is 40-70%, and the grain size becomes 30-100 microns. The copper target is heat-treated to induce a recrystallization mechanism. The recrystallized grain size increases with heat treatment temperature. The heat treatment temperature is (preferably) 300-400°C. If the heat treatment temperature exceeds 400°C, the grain size increases. If the heat treatment temperature is 300°C or lower, no grain size is generated in the recrystallized grains. The manufacturing process of the copper target in this study is as follows. Casting → Hot rolling → Cold rolling → Heat treatment → Final rolling

[0014] Patent: JP 2012-046771 (Furukawa Electric Co., Ltd.): Copper targets are manufactured at a controlled temperature before hot working. The rate of decrease in hot rolling and cooling rates after final rolling is controlled in order to control the grain size in the range of 50 to 200 microns. The manufacturing process of the copper targets in this study is as follows. Copper slab containing 99.99% or more Cu → Hot rolling → Cold working → Heat treatment.

[0015] The copper slabs are heated to 700-1,000°C before the hot rolling process. The size of each pass during hot rolling decreases by 5-30%. In the final pass of the final rolling, the decrease is 10-25%. The copper is cooled in cold water at at least 50°C / second within 60 seconds after the final hot rolling.

[0016] Patent: Patent No. 4974197 (Furukawa): Grain size affects sputtering characteristics. The grain size of this invention is 100 to 200, preferably 110 to 190 microns, and more preferably 120 to 180 microns. When the grains are small, the grain boundaries become larger. Particles or atoms in the boundary layer are obstructed. Atoms of the coating are removed from the copper target and diffuse irregularly (non-uniformly) into the substrate material during the sputtering process. Sputtering with large grain sizes requires high energy, resulting in the formation of coarse clusters of atoms and a non-uniform film coating. The copper target in this study is produced by two hot working processes: a hot rolling process and a hot extrusion process. The manufacturing process is as follows: Copper ingot (Cu=99.99% or less) → Heat (temperature = 700~1,050℃) → Hot rolling or hot extrusion → Water cooling (cooling rate = 50℃ / sec or less) → Cold rolling

[0017] For hot rolling processes: Copper cake (150mm thick x 220mm wide) → heated to approximately 1,000°C → hot rolling (multiple passes) → water cooling in the final pass of hot rolling (cooling rate = 50°C / second or less in less than 60 seconds) → copper sheet (23mm thick x 220mm wide) → surface oxide processing (0.5mm / side) → copper sheet (22mm thick x 220mm wide) → cold rolling → copper sheet (20mm thick x 200mm wide).

[0018] For hot extrusion processes: Copper ingot (300mm diameter x 800mm length) → heated to approximately 1,000°C → hot extrusion → water cooling (cooling rate = 100°C / second or less in less than 20 seconds) → copper sheet (22mm thickness x 200mm width) → cold rolling → copper sheet (20mm thickness x 200mm width)

[0019] The results showed that grain size can be controlled to the desired dimensions in both hot rolling and hot extrusion. However, the uniformity of copper grain size in the extruded process (head-end position along length and center-edge position along width) is lower than in the hot rolling process.

[0020] Patent: Patent No. 4974198 (Furukawa): Following an investigation of Patent No. 4974197, further research was conducted on the uniformity of crystal grains. The inventors found that dynamic recrystallization occurs during the hot rolling process. When the copper target is cooled in air, the problem of irregular crystal grain size occurs throughout the width and length of the copper target. In this invention, the crystal grain size is controlled by water cooling at a cooling rate of more than 50°C / second. In the hot rolling process, the copper target is cooled in water within 60 seconds. In the hot extrusion process, the copper target is cooled in water within 10 seconds after being pressed through the extrusion die. The crystal grain size at 1 / 2 and 1 / 4 thickness is 100-200 microns (+ / -10 microns). The manufacturing process is as follows: Casting → Hot rolling or hot extrusion → Cold rolling → Heat treatment (Cold rolling and heat treatment may be repeated).

[0021] Patent: JP 2013-019010 (Furukawa Electric Co., Ltd.): To reduce abnormal discharge in the sputtering process, the sputtering target material shall contain at least 99.99% copper purity, have void and inclusion defects not exceeding 30 microns, have defects not exceeding 10 points / mm2, have a grain size in the range of 50 to 200 microns, and have a hardness in the range of 60 to 100 HV. The manufacturing process is as follows. Copper slab (Cu=99.99% or higher) → Heating at 700~1,000℃ → Hot rolling (Total hot working rate %=20% or higher and hot working rate in the final hot rolling %=10% or higher at a temperature of 400~600℃) → Water cooling in the final pass of hot rolling (Cooling rate = 50℃ / sec or higher) → Oxide surface treatment → Cold rolling

[0022] Patent: Japanese Patent Publication No. 2013-133491 (Hitachi Cable Ltd): The copper target shall contain at least 99.9% copper purity and a crystal grain size in the range of 100 to 200 microns. The manufacturing process is as follows: Copper slab (Cu=99.9% or higher) → Hot rolling → Cold rolling (Cold working rate %=5~30%)

[0023] Patent: Japanese Patent Application Laid-Open No. 2014-025129 (SH Copper Product Corp (Hitachi)): The copper target shall be a grade of copper having a purity of at least 99.9% and a crystal grain size of 70 to 200 μm and 100 to 150 μm. The manufacturing process is as follows. Copper slab (Cu = 99.9% or more) → Heating at 800 to 900 °C → Hot rolling (thickness reduction rate % = 85 to 90% and temperature after hot rolling = 600 to 700 °C)

[0024] Patent: Japanese Patent Application Laid-Open No. 2015-017299 (SH Copper Product Corp (Hitachi)): The copper target shall be a grade of copper having a purity of at least 99.9% and a crystal grain size of 70 to 200 μm and 100 to 150 μm. The manufacturing process is as follows. Copper slab (Cu = 99.9% or more) → Heating at 800 to 900 °C → Hot rolling (thickness reduction rate % = 85 to 90% and temperature after hot rolling = 600 to 650 °C) → Cold rolling → Heat treatment (cold rolling and heat treatment may be repeated) → Final cold rolling (reduction rate % = 5 to 7%).

[0025] Based on previous research, it has been found that most copper target processes are 1) forging, 2) hot rolling, and 3) hot extrusion. Usually, in the forging process, a small amount of copper target is manufactured. Therefore, most copper targets are manufactured from the hot rolling or hot extrusion process because copper targets of small to large sizes can be manufactured. However, in the current trend, they are manufactured by the hot rolling process.

[0026] In recent years, research on copper targets by hot extrusion has been conducted (Furukawa Electric, 2012). By comparing the hot rolling process and the copper target manufacturing by hot extrusion, it has been found that the manufacturing process of copper targets by the hot extrusion process is less than that of the hot rolling process. Copper target manufacturing process using hot rolling: 1) Copper slab → 2) Heating at 1,000°C → 3) Hot rolling (multiple passes) → 4) Water cooling → 5) Copper sheet → 6) Oxide surface treatment → 7) Copper sheet → 8) Cold rolling → 9) Heat treatment → 10) Copper target (Note: Steps 8 and 9 can be repeated to the desired size). Copper target manufacturing process using hot extrusion: 1) Copper ingot → 2) Heating at 1,000°C → 3) Hot extrusion (only one pass) → 4) Water cooling → 5) Copper sheet → 5) Cold rolling or cold drawing → 6) Copper target

[0027] Furthermore, Furukawa Electric's patents (Patent No. 4974197 and Patent No. 4974198) study the properties of copper targets, particularly from the perspective of comparing grain size between hot rolling and hot extrusion. This study revealed that the grain size of hot rolling and hot extrusion can be controlled to a desired size. However, the uniformity of the copper grain size in the extrusion process (head-end position along length and center-edge position along width) is lower than in the hot rolling process. This means that the hot extrusion process results in more uniform grain size than the hot rolling process.

[0028] Furthermore, various studies have concluded that the surface roughness of the target is related to abnormal discharge during sputtering, which causes a problem known as "particles" or "splats." Studies have shown that copper targets have a very small grain size, resulting in a smoother surface. Therefore, reducing the grain size of the copper target can also prevent the "particle" problem. Thus, the quality of thin films produced with copper target materials is better with smaller grain sizes than with larger grain sizes. However, recent studies by Furukawa Electric (Patent Nos. 4974197 and 4974198) have revealed that the grain size of copper targets in the hot extrusion process is 100-200 microns. Copper targets suitable for use in thin film applications are produced by a hot extrusion process with a grain size of less than 100 microns. Therefore, current research led by Vatchakran Taechachoonhakij (Oriental Copper) has developed a copper target for hot extrusion with a small grain size in the range of 50-100 microns. Table 1 shows a summary of the method for manufacturing copper targets and the grain sizes obtained from past and current research.

[0029] [Table 1] [Prior art documents] [Patent Documents]

[0030] [Patent Document 1] U.S. Patent No. 5598285 [Patent Document 2] U.S. Patent Application Publication No. 2000 / 6139701 [Patent Document 3] U.S. Patent Application Publication No. 2004 / 6746553 [Patent Document 4] U.S. Patent Application Publication No. 2011 / 0139615 [Patent Document 5] Japanese Patent Publication No. 2012-046771 [Patent Document 6] Patent No. 4974197 [Patent Document 7] Patent No. 4974198 [Patent Document 8] Japanese Patent Publication No. 2013-019010 [Patent Document 9] Japanese Patent Publication No. 2013-133491 [Patent Document 10] Japanese Patent Publication No. 2014-025129 [Patent Document 11] Japanese Patent Publication No. 2015-017299 [Overview of the project] [Problems that the invention aims to solve]

[0031] Nature and purpose of the invention Previous research has concluded that the quality of thin films produced from copper target materials is better when the grain size is smaller than when the grain size is larger. Hot extrusion processes result in greater uniformity of copper grain size (head end position along length and central edge position along width) than hot rolling processes. Therefore, the present invention aims to produce a copper target for thin film coating by sputtering. The present invention is produced by a hot extrusion process that controls the copper grain size to less than 100 microns so that the coating layer or thin film is of good quality. The variables in the hot extrusion process that affect the grain size and uniformity of copper particles are as follows: 1. Extrusion ratio in the hot extrusion process 2. Temperature of the copper ingot before the hot extrusion process. 3. Extrusion speed (main RAM speed) in the hot extrusion process

[0032] In the hot extrusion process, after the copper is extruded from the extrusion die, it is rapidly cooled until it is exposed to water (water extrusion). This is an important technique to prevent copper particle growth, as shown in Figure 5.

[0033] As shown in Figure 6, after the hot extrusion process, the next process is a cold drawing process to obtain dimensions and hardness of 51-100 Vickers (HV). [Means for solving the problem]

[0034] Disclosure of the invention Copper ingots having a copper purity of at least 99.99% and an oxygen content not exceeding 5 ppm are processed by a hot extrusion process. This is the most important process for controlling the uniformity of dimensions and copper grain size. The variables investigated and controlled are 1) extrusion ratio, 2) ingot temperature, and 3) extrusion rate. 1. Extrusion Ratio: In this study, the cross-sectional area or diameter of the copper ingots used in hot extrusion, extruded from the extrusion die, is variable. The diameters of the copper ingots investigated are 10 inches and 12 inches. 2. Ingot Temperature: The temperature of the copper ingot before the hot extrusion process is 750°C, 800°C, and 850°C. 3. Extrusion speed: The extrusion speed is measured by the speed of the hydraulic cylinder used to push the copper ingot out of the extrusion die. This study will be conducted at speeds of 5, 10, and 20 mm / second.

[0035] The control variable is the cooling of the copper. Normally, after the copper is deformed in a hot extrusion process, the grain size decreases through a mechanism known as dynamic recrystallization. If the copper is cooled normally in the atmosphere after the hot extrusion process, the grain size of the copper increases.

[0036] In other studies, heated copper is cooled with water within 10 seconds after it is extruded from the extrusion die during the hot extrusion process. This allows the copper to cool sufficiently for a short time so that the recrystallization process can proceed to the particle growth process, resulting in larger and more non-uniform grain sizes.

[0037] In this study, the control of copper cooling differs from other studies where the copper is cooled immediately after being extruded from the extrusion die in a hot extrusion process. The copper is immediately moved into a water tunnel (underwater extrusion) behind the extrusion die. The copper is cooled immediately, and because the grain size is small and uniform, no grain growth process occurs. The copper is then passed through a cold drawing process to ensure that the dimensions and hardness of the target material meet the specifications of 50-100 Vickers (HV) before being manufactured in the next process. [Brief explanation of the drawing]

[0038] [Figure 1] This diagram shows a sputtering coating system. A = anode, T = target, S = workpiece, P = plasma [Figure 2] This is a diagram showing the physical sputtering process. [Figure 3] This is a diagram showing a sputtering machine. [Figure 4] This figure shows plasma formation during thin-film coating. [Figure 5] This is a diagram showing the underwater state during the hot extrusion process. [Figure 6] This is a diagram showing the cold drawing process. [Figure 7] This figure shows the position of the sample relative to the measured crystal grain size, depending on the length of the copper rod. [Figure 8] This figure shows the position of the sample relative to the measured crystal grain size, depending on the width of the copper rod. [Figure 9] This figure shows the grain size at the head position (ingot diameter 10 inches, temperature 750°C, speed 5 mm / second). [Figure 10] This figure shows the grain size at the central position (ingot diameter 10 inches, temperature 750°C, speed 5 mm / second). [Figure 11] This figure shows the grain size at the tail end (ingot diameter 10 inches, temperature 750°C, speed 5 mm / second). [Figure 12] This figure shows the grain size at the head position (ingot diameter 10 inches, temperature 750°C, speed 10 mm / second). [Figure 13] This figure shows the grain size at the central position (ingot diameter 10 inches, temperature 750°C, speed 10 mm / second). [Figure 14] This figure shows the grain size at the tail end (ingot diameter 10 inches, temperature 750°C, speed 10 mm / second). [Figure 15] This figure shows the grain size at the head position (ingot diameter 10 inches, temperature 750°C, speed 20 mm / second). [Figure 16] This figure shows the grain size at the central position (ingot diameter 10 inches, temperature 750°C, speed 20 mm / second). [Figure 17] This figure shows the grain size at the tail end (ingot diameter 10 inches, temperature 750°C, speed 20 mm / sec). [Figure 18] This figure shows the grain size at the head position (ingot diameter 10 inches, temperature 800°C, speed 5 mm / second). [Figure 19] This figure shows the grain size at the central position (ingot diameter 10 inches, temperature 800°C, speed 5 mm / second). [Figure 20] This figure shows the grain size at the tail end (ingot diameter 10 inches, temperature 800°C, speed 5 mm / second). [Figure 21] This figure shows the grain size at the head position (ingot diameter 10 inches, temperature 800°C, speed 10 mm / second). [Figure 22] This figure shows the grain size at the central position (ingot diameter 10 inches, temperature 800°C, speed 10 mm / second). [Figure 23] This figure shows the grain size at the tail end (ingot diameter 10 inches, temperature 800°C, speed 10 mm / second). [Figure 24] This figure shows the grain size at the head position (ingot diameter 10 inches, temperature 800°C, speed 20 mm / second). [Figure 25] This figure shows the grain size at the central position (ingot diameter 10 inches, temperature 800°C, speed 20 mm / second). [Figure 26]This figure shows the grain size at the tail end (ingot diameter 10 inches, temperature 800°C, speed 20 mm / second). [Figure 27] This figure shows the grain size at the head position (ingot diameter 10 inches, temperature 850°C, speed 5 mm / second). [Figure 28] This figure shows the grain size at the central position (ingot diameter 10 inches, temperature 850°C, speed 5 mm / second). [Figure 29] This figure shows the grain size at the tail end (ingot diameter 10 inches, temperature 850°C, speed 5 mm / second). [Figure 30] This figure shows the grain size at the head position (ingot diameter 10 inches, temperature 850°C, speed 10 mm / second). [Figure 31] This figure shows the grain size at the central position (ingot diameter 10 inches, temperature 850°C, speed 10 mm / second). [Figure 32] This figure shows the grain size at the tail end (ingot diameter 10 inches, temperature 850°C, speed 10 mm / second). [Figure 33] This figure shows the grain size at the head position (ingot diameter 10 inches, temperature 850°C, speed 20 mm / second). [Figure 34] This figure shows the grain size at the central position (ingot diameter 10 inches, temperature 850°C, speed 20 mm / second). [Figure 35] This figure shows the grain size at the tail end (ingot diameter 10 inches, temperature 850°C, speed 20 mm / sec). [Figure 36] This figure shows the grain size at the head position (ingot diameter 12 inches, temperature 750°C, speed 5 mm / second). [Figure 37] This figure shows the grain size at the central position (ingot diameter 12 inches, temperature 750°C, speed 5 mm / second). [Figure 38] This figure shows the grain size at the tail end (ingot diameter 12 inches, temperature 750°C, speed 5 mm / second). [Figure 39]This figure shows the grain size at the head position (ingot diameter 12 inches, temperature 750°C, speed 10 mm / second). [Figure 40] This figure shows the grain size at the central position (ingot diameter 12 inches, temperature 750°C, speed 10 mm / second). [Figure 41] This figure shows the grain size at the tail end (ingot diameter 12 inches, temperature 750°C, speed 10 mm / second). [Figure 42] This figure shows the grain size at the head position (ingot diameter 12 inches, temperature 750°C, speed 20 mm / second). [Figure 43] This figure shows the grain size at the central position (ingot diameter 12 inches, temperature 750°C, speed 20 mm / second). [Figure 44] This figure shows the grain size at the tail end (ingot diameter 12 inches, temperature 750°C, speed 20 mm / sec). [Figure 45] This figure shows the grain size at the head position (ingot diameter 12 inches, temperature 800°C, speed 5 mm / second). [Figure 46] This figure shows the grain size at the central position (ingot diameter 12 inches, temperature 800°C, speed 5 mm / second). [Figure 47] This figure shows the grain size at the tail end (ingot diameter 12 inches, temperature 800°C, speed 5 mm / second). [Figure 48] This figure shows the grain size at the head position (ingot diameter 12 inches, temperature 800°C, speed 10 mm / second). [Figure 49] This figure shows the grain size at the central position (ingot diameter 12 inches, temperature 800°C, speed 10 mm / second). [Figure 50] This figure shows the grain size at the tail end (ingot diameter 12 inches, temperature 800°C, speed 10 mm / second). [Figure 51] This figure shows the grain size at the head position (ingot diameter 12 inches, temperature 800°C, speed 20 mm / second). [Figure 52]This figure shows the grain size at the central position (ingot diameter 12 inches, temperature 800°C, speed 20 mm / second). [Figure 53] This figure shows the grain size at the tail end (ingot diameter 12 inches, temperature 800°C, speed 20 mm / second). [Figure 54] This figure shows the grain size at the head position (ingot diameter 12 inches, temperature 850°C, speed 5 mm / second). [Figure 55] This figure shows the grain size at the central position (ingot diameter 12 inches, temperature 850°C, speed 5 mm / second). [Figure 56] This figure shows the grain size at the tail end (ingot diameter 12 inches, temperature 850°C, speed 5 mm / second). [Figure 57] This figure shows the grain size at the head position (ingot diameter 12 inches, temperature 850°C, speed 10 mm / second). [Figure 58] This figure shows the grain size at the central position (ingot diameter 12 inches, temperature 850°C, speed 10 mm / second). [Figure 59] This figure shows the grain size at the tail end (ingot diameter 12 inches, temperature 850°C, speed 10 mm / second). [Figure 60] This figure shows the grain size at the head position (ingot diameter 12 inches, temperature 850°C, speed 20 mm / sec). [Figure 61] This figure shows the grain size at the central position (ingot diameter 12 inches, temperature 850°C, speed 20 mm / second). [Figure 62] This figure shows the grain size at the tail end (ingot diameter 12 inches, temperature 850°C, speed 20 mm / sec). [Modes for carrying out the invention]

[0039] Prior to the hot extrusion process, copper ingots (10 inches in diameter, 643 mm in length; 12 inches in diameter, 471 mm in length) are prepared by heating them at 750°C, 800°C, and 850°C. The heated copper ingots are immediately extruded from the extrusion die into a water tunnel (water extrusion). As shown in Table 2, the extrusion speeds are 5 mm / sec, 10 mm / sec, and 20 mm / sec. The dimensions of the copper after pressing from the extrusion die are 188 mm in width, 24 mm in thickness, and 6,000 mm in length. Next, the copper is drawn through a drawing die in a cold drawing process. The reduction rate of the cold drawing process is 14% (not exceeding 30%). The dimensions of the copper after drawing through the drawing die are 185 mm in width, 21 mm in thickness, and 7,000 mm in length. Samples for microstructure testing are cut from the head, middle, and tail positions according to the length of the copper rod, as shown in Figure 7.

[0040] [Table 2]

[0041] As shown in Figure 8, all samples (head, midsection, and tail) are examined for microstructure at the edge width, the center of the width on the surface, and at 1 / 4 and 1 / 2 of the thickness.

[0042] The microstructure results for a 10-inch diameter at various locations in the copper ingot are shown in Figures 9-35 and Table 3. The microstructure results for a 12-inch diameter at various locations in the copper ingot are shown in Figures 36-62 and Table 4.

[0043] [Table 3]

[0044] [Table 4]

[0045] Best Mode This has already been made clear in the disclosure of the invention.

Claims

1. Suppresses abnormal discharge during sputtering for thin-film coating technology using the sputtering method. To control this, a method for manufacturing a copper target in which the crystal grain size of copper is less than 100 microns and the SD (standard deviation) of the average crystal grain size of copper is 3.76 microns or less, The aforementioned sputtering method is a two-electrode sputtering method, The copper ingot is heated to 750-800°C, and the extrusion speed is 5-20 mm / second. Hot extrusion process, and A manufacturing method comprising a cold drawing process.

2. The copper target for the thin film coating technology using the sputtering method is a planar sputtering copper target. The method according to claim 1, wherein the targeting target is...

3. The copper ingots used have a diameter of 254-304.8 mm and are at least 99.99 Contains % pure copper, no oxygen exceeding 5 ppm, and no other elements exceeding 100 ppm. The method according to claim 1.

4. The method according to any one of claims 1 to 3, wherein the crystal grain size of the copper in the copper target produced by the hot extrusion process does not exceed 100 microns.

5. The hardness of the copper target produced by the cold drawing process is 100 Vickers. The method according to any one of claims 1 to 3, not exceeding .

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