Tantalum dummy bar head and manufacturing method and working method thereof

Abstract

The invention discloses a tantalum dummy bar head and a manufacturing method and a working method thereof, and relates to the technical field of tantalum dummy bar heads, the tantalum dummy bar head comprises a cylindrical tantalum and a disc tantalum, one end of the cylindrical tantalum is connected to the center of one side of the disc tantalum, and the other side of the disc tantalum is provided with an inverted conical pit; in the working process of the tantalum dummy bar head, due to the fact that the TaC nanocrystalline layer is arranged, the dummy bar head can be prevented from being damaged, due to the fact that the amorphous Ta2O5 layer is arranged, the binding force between collected metal tantalum and the dummy bar head can be reduced, self-stripping of a tantalum block and the dummy bar head is achieved through pulse current, and therefore the service life of the tantalum dummy bar head is prolonged. The collected tantalum blocks cannot be mixed with tantalum in the original dummy bar head, and the purity of the tantalum blocks is more uniform; meanwhile, the separated conical pit of the dummy bar head can be recycled after the amorphous Ta2O5 layer and the TaC nanocrystalline layer are removed through polishing, and the dummy bar head cannot be mixed with a tantalum block and does not need to be made of a high-purity tantalum material, so that the use cost can be further reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of tantalum ingot starter heads, and in particular to a tantalum ingot starter head and a manufacturing method and a working method thereof. Background Art

[0002] Tantalum has a series of excellent properties, such as high melting point, low vapor pressure, good cold processing performance, high chemical stability, strong resistance to liquid metal corrosion, and large dielectric constant of surface oxide film. Therefore, tantalum has important applications in high-tech fields such as electronics, metallurgy, steel, chemical industry, cemented carbide, atomic energy, superconducting technology, automotive electronics, aerospace, medical health and scientific research. Tantalum is one of the rare metal mineral resources and an indispensable strategic raw material for the development of the electronics industry and space technology. In addition, the target material made of high-purity tantalum material can be used as the diffusion barrier layer between copper interconnects and silicon substrates in advanced semiconductor technology, and is a key material in the copper interconnect process.

[0003] Tantalum sputtering targets have become the key raw materials for the semiconductor industry. They are irreplaceable and have broad application prospects. The conventional solution for tantalum purification is to press and sinter tantalum powder and then purify it through electron beam melting to form tantalum ingots, which are then processed by plastic deformation to prepare products. In the process of electron beam melting of metallic tantalum, a guide head is required as the beginning of melting to guide the beam to form a molten pool. The same metal material and high purity are required, otherwise doping will occur and affect the purity of the product. The specifications of tantalum ingots depend on the specifications of the crucible and the guide head, which are generally D100-D300mm. Metal tantalum is expensive and has a high density. The weight of a guide head is about 50-300kg. The larger the diameter, the higher the price.

[0004] In the prior art, the use of tantalum ingot heads is divided into small-sized tantalum ingot heads and large-sized tantalum ingot heads according to demand. When the large-sized tantalum ingot heads are used, the cost of the tantalum electron beam melting process is high due to their high price. Summary of the invention

[0005] The purpose of the present invention is to provide a tantalum ingot starter and a manufacturing method and working method thereof to solve the following technical problems:

[0006] How to reduce the cost of using tantalum ingot heads.

[0007] The purpose of the present invention can be achieved through the following technical solutions:

[0008] In a first aspect, the present invention discloses a tantalum ingot starter, comprising a tantalum cylinder and a tantalum disc, wherein one end of the tantalum cylinder is connected to the center of one side of the tantalum disc, and an inverted conical pit is formed on the other side of the tantalum disc.

[0009] In a further embodiment of the present invention, the maximum inner diameter of the conical groove is the same as the diameter of the tantalum disc, and the depth of the conical pit is 4-8 mm.

[0010] In a second aspect, the present invention discloses a method for manufacturing the tantalum ingot starter as described above, comprising the following steps:

[0011] Step 1: Select a cylindrical tantalum, and turn and remove 15-25mm of the diameter of one end of the cylindrical tantalum to form a boss at the end of the cylindrical tantalum, and the height of the boss is less than the thickness of the disc tantalum 1;

[0012] Step 2: Select another cylindrical tantalum, use a hydraulic press to upset it to form a tantalum disc, and use a water jet cutting machine to cut the center of the tantalum disc to obtain a circular ring, the inner ring diameter of which is the same as the diameter of the boss;

[0013] Step 3: insert the boss at one end of the cylindrical tantalum into the inner ring of the circular ring to assemble them into an integrated form, so that a groove is formed between the boss and the inner ring of the circular ring, fill the groove with tantalum blocks, place them in the crucible of the EB melting furnace, and then perform electron beam melting. After cooling, the groove is filled, and the cylindrical tantalum and the disc tantalum are respectively connected to the circular ring through the boss as a whole;

[0014] Step 4: A conical pit is formed by turning on the side of the disc tantalum away from the cylindrical tantalum to obtain the tantalum ingot starter.

[0015] In a further embodiment of the present invention, the parameters of the electron beam melting are: melting vacuum degree ≤5*10-3Pa, melting power 150kW, emission current 2A, and ingot rotation speed 2r / min.

[0016] In a third aspect, the present invention further discloses a method for operating the tantalum ingot starter as described above, comprising the following steps:

[0017] S1. Place the tantalum ingot head in the crucible with the pit facing upward, and then place it in a vacuum chamber, inject methane gas into the vacuum chamber, and focus the electron beam on the bottom of the conical pit for melting. During this process, the Ta in the conical pit reacts with the C in the methane gas to generate a TaC nanocrystalline layer;

[0018] S2. After the molten pool is formed, the residual O 2 Reacts with Ta to form amorphous Ta 2 O 5 layer;

[0019] S3, performing electron beam melting on the tantalum material, so that the metal tantalum falls into the molten pool for collection;

[0020] S4. After the metal tantalum is collected, it forms a tantalum block. The pulse current is switched to make the metal tantalum and Ta 2 O5 The interface of the layer contact produces a temperature rise of 50-60℃, and under the action of thermal expansion difference, the tantalum block and the ingot head are separated by themselves;

[0021] S5. Grind the side of the tantalum block that contacts the ingot guide to obtain a tantalum ingot with uniform purity.

[0022] In a further embodiment of the present invention: in step S1, the injection amount of the methane gas is the volume when the pressure of the vacuum chamber reaches 0.1 Pa.

[0023] In a further embodiment of the present invention: in step S1, the power density of the electron beam is 15 kW / cm 2 .

[0024] In a further embodiment of the present invention: in step S1, the thickness of the TaC nanocrystalline layer is 5-8 nm, the grain size is less than 10 nm, and the hardness is greater than or equal to 32 GPa.

[0025] In a further embodiment of the present invention: in step S2, the thickness of the amorphous Ta2O5 layer is 2-3 nm, and the contact angle is greater than 120°C.

[0026] In a further embodiment of the present invention: in step S4, the amplitude of the pulse current is 100A, the pulse width is 1ms, and the frequency is 10kHz.

[0027] Beneficial effects of the present invention:

[0028] (1) When manufacturing the tantalum ingot head of the present invention, a small-sized cylindrical tantalum is transformed into a large-sized disc tantalum. A boss is processed on the small-sized cylindrical tantalum to prepare a large-sized circular ring. The two are assembled and combined into an integral body through electron beam melting, thereby ensuring the bonding strength and greatly reducing the manufacturing cost of the tantalum block, thereby improving the core competitiveness of the enterprise.

[0029] (2) During the operation of the tantalum ingot starter of the present invention, damage to the ingot starter can be avoided due to the provision of the TaC nanocrystalline layer. 2 O 5 The layer can reduce the bonding force between the collected metal tantalum and the ingot head, and the pulse current is used to realize the self-stripping of the tantalum block and the ingot head. Therefore, the collected tantalum block will not be mixed with the tantalum in the original ingot head, and its purity is more uniform; at the same time, the conical pit of the separated ingot head is polished to remove the amorphous Ta 2 O 5 After forming the TaC nanocrystalline layer and the TaC nanocrystalline layer, it can be recycled to reduce the production cost of the tantalum block. Moreover, since the ingot starter will not be mixed with the tantalum block, the ingot starter does not need to use high-purity tantalum material, which can further reduce the cost of use. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The present invention will be further described below in conjunction with the accompanying drawings.

[0031] Figure 1 is a schematic structural diagram of a tantalum ingot starter in Example 1 of the present invention;

[0032] Figure 2 This is a flow chart of the production of a tantalum ingot starter in Example 2 of the present invention; wherein:

[0033] Figure (A) is a schematic diagram of step 1 of the method for making a tantalum ingot head in Example 2;

[0034] Figure (B) is a schematic diagram of step 2 of the method for making a tantalum ingot head in Example 2;

[0035] Figure (C) is a schematic diagram of step 3 of the method for making a tantalum ingot head in Example 2;

[0036] Figure (E) is a result diagram of step 3 of the method for making a tantalum ingot head in Example 2;

[0037] Figure (D) is a schematic diagram of step 4 of the method for making a tantalum ingot head in Example 2;

[0038] In the figure: 1, tantalum disc; 101, circular ring; 102, conical pit; 103, groove; 2, tantalum cylinder; 201, boss. DETAILED DESCRIPTION

[0039] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0040] Example 1

[0041] See also Figure 1 This embodiment discloses a tantalum ingot head, including a tantalum cylinder 2 and a tantalum disc 1, one end of the tantalum cylinder 2 is connected to the center of one side of the tantalum disc 1, and an inverted conical pit 202 is opened on the other side of the tantalum disc 1.

[0042] The diameter of the tantalum disc 1 is 230 mm and the height is 50 mm, the diameter of the tantalum cylinder 2 is 120 mm and the length is 100 mm; the maximum inner diameter of the conical pit 202 is the same as the diameter of the tantalum disc 1, and the depth of the conical pit 202 is 5 mm.

[0043] It should be noted that the sizes of the disc tantalum 1 and the cylindrical tantalum 2 are not limited to those in the present embodiment. In other embodiments, their sizes can be adjusted accordingly according to actual conditions. At the same time, the depth of the conical pit 202 is not limited to 5 mm in the present embodiment. In other embodiments, its depth can be set to other values, as long as it meets 4-8 mm.

[0044] When the tantalum ingot head in this embodiment is in use, one end of the tantalum disc 1 is used as the use end and is placed on the upper part of the crucible. The diameter of the cylindrical tantalum 2 at the bottom is significantly smaller than that of the tantalum disc 1, thereby saving tantalum material and reducing the cost of use.

[0045] Example 2

[0046] See also Figure 2 This embodiment discloses a method for manufacturing the tantalum ingot starter described in Embodiment 1, which specifically includes the following steps:

[0047] Step 1: Please refer to Figure 2 In the figure (A), a cylindrical tantalum 2 with a diameter of 120nm and a length of 120nm is selected, and 20mm of the diameter of one end of the cylindrical tantalum 2 is removed by turning, so that a boss 201 with a diameter of 100mm is formed at the end of the cylindrical tantalum, and the height of the boss 201 is less than the thickness of the disc tantalum 1;

[0048] Step 2: Please refer to Figure 2 In the figure (B), another cylindrical tantalum 2 is selected, and after being upset by a hydraulic press, a disc tantalum 1 with a diameter of 230 mm and a height of 50 mm is formed. The center of the disc tantalum 1 is cut by a water jet cutting machine to obtain a circular ring 101. The inner ring diameter of the circular ring 101 is the same as the boss diameter, both of which are 100 mm.

[0049] Step 3: Please refer to Figure 2 As shown in Figure (C), the boss 201 at one end of the cylindrical tantalum 1 is inserted into the inner ring of the circular ring 101 to be assembled as an integral body, and a groove 103 is formed between the boss 201 and the inner ring of the circular ring 101; a tantalum block is filled into the groove 103, placed in a crucible of an EB melting furnace, and then electron beam melting is performed, the melting vacuum degree is ≤5*10-3Pa, the melting power is 150kw, the emission current is 2A, and the ingot rotation rate is 2r / min; after cooling, the groove 103 is filled, and the cylindrical tantalum 2 and the disc tantalum 1 are respectively connected to the circular ring 101 as a whole through the boss 201, as shown in the following figure. Figure 2 As shown in Figure (D);

[0050] Step 4: Please refer to Figure 2 In the figure (E), a conical pit 202 is turned on the side of the tantalum disc 1 away from the cylindrical tantalum 2 to obtain a tantalum ingot head.

[0051] It should be noted that the various parameters in this embodiment are not specifically limited and can be adjusted accordingly according to actual application conditions. For example, the diameter of one end of the cylindrical tantalum 2 can be turned and removed in the range of 15-25 mm.

[0052] In the method for manufacturing the tantalum ingot head of the present embodiment, a small-sized cylindrical tantalum 2 can be used to obtain a large-sized disc tantalum 1, and the cylindrical tantalum 2 and the disc tantalum 1 are integrated through electron beam melting, which can ensure the bonding strength of the two and greatly reduce the manufacturing cost of the large-sized tantalum ingot head.

[0053] Example 3

[0054] This embodiment discloses a working method of the tantalum ingot starter described in Example 1, comprising the following steps:

[0055] S1. Place the tantalum ingot head in a crucible with the conical pit 102 on the cylindrical tantalum 1 facing upwards, and then place it in a vacuum chamber. Inject methane gas into the vacuum chamber to make the pressure of the vacuum chamber reach 0.1 Pa. The power density is 15 kW / cm 2 The electron beam is focused on the bottom of the conical pit 102 for melting. During this process, the Ta in the conical pit 102 reacts with the C in the methane gas to generate a TaC nanocrystalline layer with a thickness of 5-8nm, a grain size of less than 10nm, and a hardness of ≥32GPa. The TaC nanocrystalline layer has high strength and anti-erosion performance, which can prevent the tantalum ingot from being damaged when the electron beam is used to melt and collect the tantalum material;

[0056] S2. After the molten pool is formed, the residual O in the conical pit 102 2 Reacts with Ta to generate amorphous Ta with a thickness of 2-3nm and a contact angle of >120° 2 O 5 The layer can reduce the surface energy of tantalum on the surface of the molten pool, reduce the wettability of the molten tantalum liquid, and thus reduce the adhesion with the subsequently deposited metal tantalum;

[0057] S3. Perform normal electron beam melting process on tantalum material, let the metal tantalum fall into the molten pool for collection, and there is TaC nanocrystalline layer and amorphous Ta between the metal tantalum and the molten pool. 2 O 5 The layer is isolated, so the bonding force between the starter head and the starter head is low without damaging the starter head;

[0058] S4. After the metal tantalum is collected, a tantalum block is formed. The pulse current is switched. The amplitude of the pulse current is 100A, the pulse width is 1ms, and the frequency is 10kHz. The Joule heating effect causes the metal tantalum and Ta to 2 O 5 The interface of the layer contact generates a temperature rise of 50-60℃. Under the action of thermal expansion difference, the tantalum block and the ingot head are self-separated, and the tantalum block and the ingot head can be directly separated without turning.

[0059] S5. Grind the side of the tantalum block that contacts the ingot guide to remove a small amount of impurities and obtain a tantalum ingot with uniform purity.

[0060] During the operation of the ingot starter of this embodiment, the TaC nanocrystalline layer is provided to avoid damage to the ingot starter. 2 O 5 The layer can reduce the bonding force between the collected metal tantalum and the ingot head, and the pulse current is used to realize the self-stripping of the tantalum block and the ingot head. Therefore, the collected tantalum block will not be mixed with the tantalum in the original ingot head, and its purity is more uniform; at the same time, the conical pit 102 of the separated ingot head is polished to remove the amorphous Ta 2 O 5 After forming the TaC nanocrystalline layer and the TaC nanocrystalline layer, it can be recycled to reduce the production cost of the tantalum block. Moreover, since the ingot starter will not be mixed with the tantalum block, the ingot starter does not need to use high-purity tantalum material, which can further reduce the cost of use.

[0061] In the description of the present invention, it should be understood that the terms "upper", "lower", "left", "right", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction and a specific direction structure and operation, and therefore, cannot be understood as a limitation on the present invention. In addition, "first" and "second" are only for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0062] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", etc. should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0063] The above is a detailed description of an embodiment of the present invention, but the content is only a preferred embodiment of the present invention and cannot be considered to limit the scope of implementation of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of the patent coverage of the present invention.

Claims

1. A tantalum ingot starter, characterized in that: The invention comprises a cylindrical tantalum (2) and a disc tantalum (1), wherein one end of the cylindrical tantalum (2) is connected to the center of one side of the disc tantalum (1), and the other side of the disc tantalum (1) is provided with an inverted conical pit (102).

2. The tantalum ingot starter according to claim 1, characterized in that: The maximum inner diameter of the conical pit (102) is the same as the diameter of the tantalum disc (1), and the depth of the conical pit (102) is 4-8 mm.

3. A method for manufacturing a tantalum ingot starter as claimed in any one of claims 1 to 2, characterized in that: The steps include: Step 1, select a cylindrical tantalum (2), and turn and remove 15-25 mm of the diameter of one end of the cylindrical tantalum (2) to form a boss (201) at the end of the cylindrical tantalum, wherein the height of the boss (201) is less than the thickness of the disc tantalum 1; Step 2: another cylindrical tantalum (2) is selected, and a hydraulic press is used to upset it to form a tantalum disc (1), and a water jet cutting machine is used to cut the center of the tantalum disc (1) to obtain a circular ring (101), wherein the inner ring diameter of the circular ring (101) is the same as the diameter of the boss (201); Step 3: insert the boss (201) at one end of the cylindrical tantalum (1) into the inner ring of the circular ring (101) to form an integral assembly, so that a groove (103) is formed between the boss (201) and the inner ring of the circular ring (101), fill the groove (103) with a tantalum block, place it in an EB melting furnace crucible, and then perform electron beam melting. After cooling, the groove (103) is filled and leveled, and the cylindrical tantalum (2) and the disc tantalum (1) are respectively connected to the circular ring (101) through the boss (201) to form an integral assembly; Step 4: A conical recess (102) is formed by turning on the side of the tantalum disc (1) away from the tantalum cylinder (2), thereby obtaining the tantalum ingot starter.

4. The method for manufacturing a tantalum ingot starter according to claim 3, characterized in that: In step three, the parameters of the electron beam melting are: melting vacuum ≤ 5*10-3Pa, melting power 150kW, emission current 2A, and ingot rotation speed 2r / min.

5. A method for operating a tantalum ingot starter as claimed in claim 1, characterized in that: The steps include: S1, placing a tantalum ingot starter in a crucible with the conical pit (102) on the cylindrical tantalum (1) facing upwards, and then placing it in a vacuum chamber, injecting methane gas into the vacuum chamber, and focusing an electron beam on the bottom of the conical pit (102) for melting, during which the Ta in the conical pit (102) reacts with the C in the methane gas to generate a TaC nanocrystalline layer; S2. After the molten pool is formed, the residual O2 in the conical pit (102) reacts with Ta to form an amorphous Ta2O5 layer; S3, performing electron beam melting on the tantalum material, so that the metal tantalum falls into the molten pool for collection; S4. After the metal tantalum is collected, a tantalum block is formed. The pulse current is switched, and the interface between the metal tantalum and the Ta2O5 layer is heated by 50-60°C through the Joule heat effect. Under the effect of the thermal expansion difference, the tantalum block and the ingot head are separated by themselves. S5. Grind the side of the tantalum block that contacts the ingot guide to obtain a tantalum ingot with uniform purity.

6. The method for operating a tantalum ingot starter according to claim 5, characterized in that: In step S1, the injection amount of the methane gas is the volume when the pressure of the vacuum chamber reaches 0.1 Pa.

7. The method for operating a tantalum ingot starter according to claim 5, characterized in that: In step S1, the power density of the electron beam is 15 kW / cm 2 .

8. The method for operating a tantalum ingot starter according to claim 5, characterized in that: In step S1, the thickness of the TaC nanocrystalline layer is 5-8 nm, the grain size is less than 10 nm, and the hardness is ≥32 GPa.

9. The method for operating a tantalum ingot starter according to claim 5, characterized in that: In step S2, the thickness of the amorphous Ta2O5 layer is 2-3 nm, and the contact angle is greater than 120°.

10. The working method of the tantalum ingot starter according to claim 5, characterized in that: In step S4, the amplitude of the pulse current is 100A, the pulse width is 1ms, and the frequency is 10kHz.

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