Tungsten heating wire, method for manufacturing the same, and vapor deposition apparatus

Abstract

This invention discloses a tungsten heating wire, its preparation method, and a vapor deposition apparatus, comprising: providing a shaped tungsten heating wire, the shaped tungsten heating wire including at least a bent structure; an electrolytic cleaning step: placing the shaped tungsten heating wire in an electrolyte for electrolytic cleaning to at least remove the oxide layer; and an annealing step: annealing the electrolytically cleaned shaped tungsten heating wire to obtain the tungsten heating wire; wherein, in the annealing step, the heating rate is 40℃ / s~50℃ / s, and the heating temperature is 1400℃~1600℃. Precision bending followed by electrolytic cleaning can remove the oxide layer on the surface of the shaped tungsten heating wire. Annealing the shaped tungsten heating wire allows for rapid heating and instantaneous heat preservation to prevent material deformation, greatly improving the service life of the tungsten heating wire and thus increasing wafer production efficiency.

Description

Technical Field

[0001] This invention relates to the field of semiconductor technology, specifically to a tungsten heating wire, its preparation method, and a vapor deposition apparatus. Background Technology

[0002] Metal-organic chemical vapor deposition (MOCVD) is a core process for fabricating LEDs and power devices. In MOCVD equipment, the tungsten heating wire serves as the core heating element within the cavity, and its quality and lifespan directly affect the temperature field uniformity and production efficiency of the deposited wafer. This tungsten heating wire has a relatively small diameter and operates at temperatures as high as 1500℃~2000℃.

[0003] Currently, existing methods for preparing tungsten heating wires include conventional cleaning and box furnace hydrogen annealing processes. However, these methods often result in problems such as difficulty in removing the oxide layer on the surface of the tungsten heating wire and easy deformation of the tungsten heating wire, which greatly shortens the service life of the tungsten heating wire and thus affects the utilization rate of MOCVD equipment and the yield of wafers.

[0004] The statements herein provide only background information in relation to this invention and do not necessarily constitute prior art. Summary of the Invention

[0005] The purpose of this invention is to overcome the defects of tungsten heating wires prepared by existing processes, such as easy deformation and short service life, and to provide a preparation method that can significantly extend the service life of tungsten heating wires for MOCVD equipment.

[0006] To achieve the above objectives, the present invention provides a method for preparing a tungsten heating wire, comprising: A molded tungsten heating wire is provided, the molded tungsten heating wire comprising at least a bending structure; Electrolytic cleaning step: The shaped tungsten heating wire is placed in an electrolyte for electrolytic cleaning to at least remove the oxide layer; Annealing process: The shaped tungsten heating wire after electrolytic cleaning is annealed to obtain the tungsten heating wire; In the annealing process, the heating rate is 40℃ / s~50℃ / s and the heating temperature is 1400℃~1600℃.

[0007] Optionally, in the electrolytic cleaning step, the electrolyte is an alkaline electrolyte.

[0008] Optionally, the alkaline electrolyte contains at least one of sodium hydroxide, sodium carbonate, and sodium dodecyl sulfate.

[0009] Optionally, the alkaline electrolyte comprises sodium hydroxide, sodium carbonate, sodium dodecyl sulfate, and deionized water; wherein the mass concentration of sodium hydroxide is 13% to 23%, the mass concentration of sodium carbonate is 1% to 11%, and the mass concentration of sodium dodecyl sulfate is 0.3% to 1.3%.

[0010] Optionally, in the electrolytic cleaning step, the current density is 0.6 A / dm³. 2 ~1.0A / dm 2 The electrolytic cleaning time is 4 min to 6 min, and the temperature is 40℃ to 50℃.

[0011] Optionally, the annealing process is an induction annealing process.

[0012] Optionally, the holding time in the annealing process is 10s to 30s.

[0013] Optionally, the annealing process can be performed in a hydrogen atmosphere.

[0014] Optionally, in the annealing process, the cooling rate is 15℃ / s to 25℃ / s.

[0015] Optionally, after the electrolytic cleaning step and before the annealing step, the process further includes cleaning the shaped tungsten heating wire after electrolytic cleaning with deionized water and anhydrous ethanol.

[0016] Optionally, the bending structure is obtained by bending a tungsten-doped wire at a high temperature of 500℃~600℃.

[0017] The present invention also provides a tungsten heating wire, which is prepared by the preparation method described above.

[0018] Optionally, the diameter of the tungsten heating wire is 0.5 mm to 1.0 mm.

[0019] Optionally, the operating temperature of the tungsten heating wire is 1500℃~2000℃.

[0020] The present invention also provides a vapor deposition apparatus, the vapor deposition apparatus comprising at least: reaction chamber; A substrate carrier stage, which is located within the reaction chamber; A heating assembly is located below the substrate support stage and is vertically spaced a distance from the substrate support stage; the heating assembly includes a main heater and an auxiliary heater, the auxiliary heater including a tungsten heating wire as described above.

[0021] Optionally, the main heater includes several arc-shaped main heating sections and connecting portions connecting adjacent arc-shaped main heating sections, and the auxiliary heater is disposed around the connecting portions or between the adjacent arc-shaped main heating sections.

[0022] Compared to the prior art, the beneficial effects of the present invention include at least the following: This invention relates to a shaped tungsten heating wire with a bent structure obtained by precisely bending a doped tungsten wire. The bent areas form a denser oxide layer. The shaped tungsten heating wire is then placed in an alkaline electrolyte for electrolytic cleaning. Due to the significant difference in electrochemical activity between tungsten oxide and the tungsten substrate, the chemical reaction preferentially occurs in the oxide layer. Therefore, electrolytic cleaning can precisely remove the oxide layer from complex areas such as the bent structure, while the etching of the tungsten substrate is extremely weak. This achieves a clean tungsten substrate surface while avoiding over-corrosion and thinning of the tungsten substrate, ensuring the dimensional accuracy and surface quality of the tungsten heating wire. This provides a uniform pretreatment foundation for subsequent rapid heating annealing. The electrolytically cleaned shaped tungsten heating wire is then annealed using a rapid heating annealing process, rapidly raising the temperature to 1400℃~1600℃ at a rate of 40℃ / s~50℃ / s. This prevents the shaped tungsten heating wire from being in the high-temperature zone for extended periods, inhibiting recrystallization and abnormal grain growth of the tungsten material, and preventing deformation of the tungsten material. This invention combines electrolytic cleaning and rapid heating annealing to produce a finished tungsten heating wire with a service life of over 4500 hours, which is more than 4.5 times longer than existing tungsten heating wires. This significantly reduces the frequency of downtime for MOCVD equipment replacement and greatly improves the production efficiency of chip deposition. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the structure of an MOCVD device according to an embodiment of the present invention.

[0024] Figure 2 This is a schematic diagram of the heating component of the present invention applied to an MOCVD equipment.

[0025] Figure 3 This is a schematic flowchart of a method for preparing a tungsten heating wire according to the present invention.

[0026] Figure 4 This is a schematic diagram of the tungsten heating wire of the present invention.

[0027] Figure 5 This is a photograph of the tungsten heating wire prepared according to an embodiment of the present invention after a life test.

[0028] Figure 6-8 The images show the tungsten heating wires prepared in Comparative Examples 1-3 of this invention after their lifespan tests were completed.

[0029] Figure Labels 1- Heating component, 2- Reaction chamber, 3- Substrate support platform, 10- Main heater, 12- Arc-shaped main heating section, 14- Connecting part, 20- Heat insulation shield, 100- Auxiliary heater, 110- Connector, 120- Heating section, 122- Sub-heating section, 123- Arc-shaped heating section. Detailed Implementation

[0030] The following detailed description, in conjunction with the accompanying drawings and specific embodiments, provides a further detailed explanation of the tungsten heating wire, its preparation method, and the vapor deposition equipment proposed in this invention. The advantages and features of this invention will become clearer from the following description. It should be noted that the drawings are in a very simplified form and use non-precise proportions, used only to facilitate and clearly illustrate the embodiments of this invention. Please refer to the drawings to make the objectives, features, and advantages of this invention more apparent and understandable. It should be understood that the structures, proportions, sizes, etc., depicted in the accompanying drawings are only for illustrative purposes to aid those skilled in the art and are not intended to limit the implementation conditions of this invention. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to the size, without affecting the effects and objectives achieved by this invention, should still fall within the scope of the technical content disclosed in this invention.

[0031] definition Bending structure: In this invention, "bending structure" refers to a non-linear structure formed by bending tungsten-doped wires, such as an arc-shaped bend.

[0032] In semiconductor equipment, MOCVD equipment has extremely high requirements for wafer temperature uniformity. The temperature difference across the entire wafer typically needs to be controlled within ±1℃. The equipment often employs a zoned heating structure with multiple sets of independently arranged heating wires to fine-tune the local temperature field and compensate for heat dissipation differences. On one hand, small-diameter tungsten heating wires are compact and flexible in arrangement, and can be densely arranged in rings, lines, or other forms within the narrow space below the substrate stage. This not only divides the space into multiple independent heating zones but also precisely fills the gaps and blind spots of the main heater, achieving localized temperature regulation. On the other hand, small-diameter tungsten heating wires have a small cross-sectional area and higher resistance, allowing for efficient conversion of electrical energy into heat energy. This results in rapid heating, low response delay, and facilitates real-time power adjustment by the equipment control system, adapting to the frequent heating and cooling and dynamic temperature control requirements of MOCVD equipment.

[0033] Figure 1 This is a schematic diagram of the structure of an MOCVD device according to an embodiment of the present invention. Figure 1As shown, the MOCVD equipment includes at least a reaction chamber 2, a rotatable substrate support stage 3, and a heating assembly 1. The substrate support stage 3 is located within the reaction chamber 2 and has a rotation axis. The heating assembly 1 is located below the substrate support stage 3 and is vertically spaced a distance from the substrate support stage 3, heating the substrate support stage 3 radiatively.

[0034] Figure 2 This is a schematic diagram of the heating component 1 of the present invention applied in an MOCVD device. (See diagram below.) Figure 2 As shown, the heating assembly 1 is fixed on the heat insulation shield 20 and includes a main heater 10 and auxiliary heaters 100. The main heater 10 includes several arc-shaped main heating sections 12 and connecting portions 14 connecting two adjacent arc-shaped main heating sections. Several auxiliary heaters 100 are arranged between the connecting portions 14 or between two adjacent arc-shaped main heating sections 12. Each auxiliary heater 100 includes an insulating plate (not shown in the figure), on which a tungsten heating wire is disposed. The insulating plate has two through holes, and the auxiliary heater 100 also includes two terminals, which pass through the through holes of the insulating plate and make electrical contact with the connectors at both ends of the tungsten heating wire. The diameter of the tungsten heating wire is 0.5mm to 1.0mm.

[0035] The existing process for preparing tungsten heating wires in MOCVD equipment typically includes: doped tungsten wire → precision bending and forming → wet cleaning such as alkaline / acid washing → box furnace hydrogen annealing → finished tungsten heating wire. However, this preparation method has the following technical drawbacks: (i) Conventional chemical immersion cleaning methods such as alkaline washing / acid washing can only remove surface dust and thin oxide layers from the tungsten heating wire. They are difficult to completely remove the dense oxide layers formed during the bending process, located in the bend fillets and stress concentration areas. If the cleaning time is insufficient, oxide layers will remain at the bend fillets; if the cleaning time is extended, over-corrosion will occur in areas with thinner oxide layers, thereby damaging the tungsten substrate and affecting dimensional accuracy. The remaining oxide layer will induce grain boundary corrosion and crack formation during subsequent high-temperature cycling, ultimately leading to premature breakage of the tungsten heating wire.

[0036] (II) Conventional box furnace hydrogen annealing processes use heating rods for heating via heat conduction, resulting in slow heating and cooling rates. This leads to excessively long dwell times (e.g., over 60 minutes) of tungsten heating wires in a bent state with residual internal stress in high-temperature regions above 1200°C. Prolonged high-temperature treatment causes complete recrystallization and abnormal grain growth in the tungsten heating wire, leading to weakened grain boundaries and embrittlement. Tungsten heating wires prepared in this way are highly susceptible to dimensional deformation due to creep during long-term high-temperature use, severely affecting the uniformity of the temperature field. Their service life is typically less than 1000 hours, often requiring frequent shutdowns to replace the tungsten heating wires, significantly reducing equipment operating efficiency.

[0037] To address the technical problem of short service life of tungsten heating wires, this invention provides a method for preparing tungsten heating wires, comprising: precisely bending a doped tungsten wire to obtain a shaped tungsten heating wire; electrolytically cleaning the shaped tungsten heating wire with an alkaline electrolyte to remove its surface oxide layer, especially the dense oxide layer generated in complex areas during the precision bending process; and annealing the electrolytically cleaned shaped tungsten heating wire using a rapid heating annealing process, thereby eliminating internal stress through rapid heating and instantaneous heat preservation, preventing recrystallization and abnormal grain growth of the tungsten material. The resulting tungsten heating wire has a service life of over 4500 hours and is suitable for metal-organic chemical vapor deposition equipment.

[0038] like Figure 3 As shown, the present invention provides a method for preparing a tungsten heating wire, comprising: Step S1: Provide a shaped tungsten heating wire, wherein the shaped tungsten heating wire includes at least a bent structure.

[0039] Tungsten-doped wires possess significantly higher hardness and stiffness (elastic modulus) than common metals such as steel, copper, and aluminum. To obtain a shaped tungsten heating wire, a doped tungsten wire is typically provided and then precisely bent. However, due to the unique physical properties of doped tungsten wires, bending them at room temperature is difficult. This is because at this temperature, atomic thermal vibration energy is low, making it difficult for dislocations to slide along slip planes. When bending stress is applied, the metal cannot release stress through plastic deformation and can only undergo intergranular / transgranular fracture directly. The bending angle and curvature are completely uncontrollable, making precision forming extremely challenging.

[0040] To obtain tungsten heating wires that meet production requirements, this invention involves precision bending and shaping of doped tungsten wires at a high temperature of 500℃~600℃, resulting in the following... Figure 4The diagram shows a finished tungsten heating wire with a bent structure. The doped tungsten wire is preferably a potassium tungsten wire, such as the WK series in GB / T 4181. The tungsten heating wire includes a heating section 120 and connectors 110 located at both ends of the heating section 120. The heating section 120 includes several parallel sub-heating sections 122 and an arc-shaped heating section 123 connecting two adjacent sub-heating sections. In this embodiment, the arc-shaped heating section 123 is the bent structure. When the ambient temperature rises above the ductile-brittle transition temperature of tungsten, atomic thermal vibrations intensify, significantly reducing the energy barrier for dislocation movement and grain boundary sliding. Various lattice slip systems are fully activated, and the doped tungsten wire gradually transforms from a brittle state to a ductile state. During deformation, stress can be evenly distributed, and shaping is completed by continuous and stable lattice slip. The surface of the bent area is smooth and free from cracks and defects. At the same time, the overall deformation resistance of tungsten decreases significantly at high temperatures, requiring less force for bending. Combined with tooling and molds, the bending angle, curvature, and forming dimensions can be more precisely controlled.

[0041] Step S2, Electrolytic cleaning step: The shaped tungsten heating wire is placed in an electrolyte for electrolytic cleaning to at least remove the oxide layer.

[0042] Tungsten is chemically stable at room temperature and reacts very slowly with oxygen. However, after undergoing high-temperature precision bending, the increased atomic and molecular motion at elevated temperatures significantly accelerates the reaction rate. Simultaneously, the protective oxide film on the tungsten surface cracks and fails due to heat, allowing oxygen to continuously contact the internal matrix, further intensifying oxidation. Therefore, tungsten is more easily oxidized at high temperatures, resulting in a greater amount of oxide on the surface of the formed tungsten heating wire after precision bending. Current technologies use chemical immersion for conventional cleaning of the doped tungsten wire to remove the oxide layer. However, the formed tungsten heating wire obtained after precision bending contains bent structures, which have the following structural characteristics that make cleaning difficult: (i) During the bending process, the tungsten wire needs to be bent at a high temperature of about 500°C. In the bent structure area, due to local deformation and uneven temperature distribution, an oxide layer that is thicker, denser and more firmly adhered than the straight section will be formed. This dense oxide layer has high chemical stability and conventional chemical soaking methods such as alkaline washing / acid washing are difficult to completely dissolve or peel off.

[0043] (ii) During conventional chemical immersion cleaning, the cleaning solution is difficult to fully penetrate into some of the micro gaps in the bent structure area, resulting in the cleaning solution being unable to effectively contact and react with the oxide layer, thus causing oxide layer residue.

[0044] To overcome the shortcomings of existing cleaning processes, this invention employs an electrolytic cleaning process to clean shaped tungsten heating wires after precision bending. Tungsten oxide is rapidly converted into soluble tungstates and removed under an alkaline electric field. Due to the significant difference in electrochemical activity between tungsten oxide and metallic tungsten, the chemical reaction preferentially occurs in the oxide layer during electrolytic cleaning, resulting in minimal etching of the tungsten substrate. This approach completely removes the oxide layer while avoiding over-corrosion of the substrate, ensuring the dimensional accuracy and surface quality of the tungsten wire.

[0045] In this invention, the electrolyte is an alkaline electrolyte, which contains at least one of sodium hydroxide, sodium carbonate, and sodium dodecyl sulfate. In some embodiments, the alkaline electrolyte contains sodium hydroxide, sodium carbonate, sodium dodecyl sulfate, and deionized water, wherein the mass concentration of sodium hydroxide is 13% to 23%, the mass concentration of sodium carbonate is 1% to 11%, and the mass concentration of sodium dodecyl sulfate is 0.3% to 1.3%.

[0046] When removing oxide layers via electrolytic cleaning, the current density, cleaning time, and temperature all affect the removal efficiency and the condition of the workpiece. Current density determines the intensity of the electrochemical reaction. If the current density is too low, the reduction and dissolution rate of the oxide layer is slow, making it difficult to completely remove dense or thick oxide layers, easily resulting in localized residues. If the current density is too high, the tungsten heating wire will undergo electrolytic corrosion during electrolysis, leading to wire diameter thinning. For some small-diameter tungsten heating wires, further reduction in wire diameter during electrolytic cleaning will directly affect the final usability of the workpiece. In some embodiments, the preferred current density is 0.6 A / dm³. 2 ~1.0A / dm 2 The electrolytic cleaning time is related to the current density; generally, the higher the current density, the shorter the electrolytic cleaning time. This invention needs to effectively remove the oxide layer on the surface of the molded tungsten heating wire while ensuring the dimensional accuracy and surface quality of the molded tungsten heating wire. Therefore, the current density and electrolytic cleaning time need to be precisely controlled. In some embodiments, the electrolytic cleaning time is preferably 4 to 6 minutes. The temperature of the electrolyte changes the ion activity and mass transfer efficiency. If the temperature is too low, the ion migration rate in the electrolyte is slow, the overall electrochemical reaction is inhibited, and the electrolytic cleaning time increases significantly. Appropriate heating can accelerate ion diffusion, improve reaction activity, and shorten the electrolytic cleaning time. In some embodiments, the electrolyte temperature is preferably 40°C to 50°C.

[0047] In some embodiments, after electrolytic cleaning, the shaped tungsten heating wire is typically cleaned with deionized water and anhydrous ethanol to remove residues from its surface.

[0048] Step S3, Annealing treatment: The shaped tungsten heating wire after electrolytic cleaning is annealed to obtain the tungsten heating wire. Residual stress exists inside the bent tungsten heating wire. The annealing treatment step of this invention, through rapid heating and instantaneous heat preservation, can remove the deformation stress generated by bending, improving overall strength and service life.

[0049] In traditional box furnace annealing processes, heating is achieved through heating rods. The entire furnace must first be heated to a specified temperature, and the tungsten heating wire provides heat through conduction. The biggest drawback is the slow heating rate. This slow heating rate results in the material spending a longer time in the high-temperature range, which can alter the material's microstructure, causing complete recrystallization and grain growth, leading to a decrease in the material's mechanical properties.

[0050] To achieve rapid heating and instantaneous heat preservation, the annealing process of this invention employs a heating rate of 40°C / s to 50°C / s, a heating temperature of 1400°C to 1600°C, and a heat preservation time of 10s to 30s. Subsequently, the wire is cooled to room temperature in a hydrogen atmosphere at a cooling rate of 15°C / s to 25°C / s. The annealing process provided by this invention can completely eliminate the internal stress of the tungsten heating wire without causing changes in its microstructure. As an example, the annealing treatment of this invention uses induction annealing to achieve rapid heating and instantaneous heat preservation. Specifically, the formed tungsten heating wire is placed in a magnetic field, and an induction coil generates an alternating magnetic field. This alternating magnetic field induces eddy currents within the formed tungsten heating wire, achieving heating through resistance heating.

[0051] Induction annealing temperatures can reach as high as 1400℃~1600℃. Under these high-temperature conditions, oxygen in the environment reacts with tungsten atoms on the surface of the shaped tungsten heating wire to generate tungsten oxide. To prevent the shaped tungsten heating wire from being oxidized again during the annealing process, this invention uses hydrogen as a reducing protective gas and performs induction annealing in a hydrogen atmosphere.

[0052] In rapid induction annealing, the presence of a dense oxide layer in the bending area can cause serious problems. First, due to the significant difference in thermal emissivity and thermal conductivity between tungsten oxide and metallic tungsten, the oxide layer area absorbs more energy and experiences poor heat dissipation during induction heating, leading to localized overheating. The temperature may far exceed the preset value, potentially causing localized overburning or melting of the tungsten substrate, resulting in irreversible thermal damage. Second, the mismatch in thermal expansion coefficients between tungsten oxide and metallic tungsten, under the rapid heating conditions of induction heating, results in different expansion rates, generating significant thermal stress at the interface. This easily induces surface microcracks, which can propagate into fracture sources during subsequent use, severely reducing the toughness of the heating wire. In this invention, the oxide layer, especially the dense oxide layer in the bending area, is thoroughly removed during the electrolytic cleaning step, eliminating the potential hazards caused by the oxide layer during induction annealing.

[0053] Example This embodiment provides a method for preparing a tungsten heating wire, comprising the following steps: Step 1: Provide a 1mm diameter doped tungsten wire, heat it in a 500℃ oven environment, and then bend it according to the design drawings of the heating component to obtain a shaped tungsten heating wire with a bending structure.

[0054] Step 2: Using the shaped tungsten heating wire obtained in Step 1 as the anode and the stainless steel plate as the cathode, electrolytic cleaning is performed in an electrolyte solution. The electrolyte solution consists of: 18% sodium hydroxide (mass concentration), 6% sodium carbonate (mass concentration), 0.8% sodium dodecyl sulfate (mass concentration), and the balance being deionized water. The electrolytic cleaning process conditions are: electrolyte temperature 45℃, voltage 10V, and current density 0.6A / dm³. 2 Electrolytic cleaning time is 4 minutes. After electrolytic cleaning, the shaped tungsten heating wire is removed and ultrasonically cleaned in deionized water for 5 minutes, followed by cleaning with anhydrous ethanol to remove residual moisture on the surface, resulting in a clean shaped tungsten heating wire.

[0055] Step 3: Place the shaped tungsten heating wire, after electrolytic cleaning in Step 2, into the induction heating chamber and introduce high-purity hydrogen gas (H2, purity 99.999%) as a protective atmosphere. Start induction heating and rapidly heat from room temperature to 1600℃ at a heating rate of 50℃ / s, and hold at this temperature for 10s. After holding, rapidly cool to room temperature at a cooling rate of 20℃ / s under the protection of the hydrogen atmosphere to obtain the finished tungsten heating wire.

[0056] The finished tungsten heating wire prepared in this embodiment was installed in an MOCVD device, and its service life was tested at a working temperature of 1500℃~2000℃.

[0057] Comparative Example 1 This comparative example provides a method for preparing a tungsten heating wire, comprising the following steps: Step 1: Same as Step 1 in Example 1, using the same doped tungsten wire and bending process to obtain the shaped tungsten heating wire.

[0058] Step 2: The shaped tungsten heating wire obtained in Step 1 is subjected to alkaline washing. The alkaline washing step is as follows: the shaped tungsten heating wire is immersed in a 5% sodium hydroxide solution at a solution temperature of 60°C for 15 minutes. After alkaline washing, it is ultrasonically cleaned with deionized water to remove residual alkaline solution and reaction byproducts from the surface.

[0059] Step 3: Place the cleaned shaped tungsten heating wire from Step 2 into a box-type annealing furnace, and introduce hydrogen gas as a protective atmosphere. Heat is applied by heat conduction at a rate of 10℃ / min, raising the temperature from room temperature to 1600℃, and holding at this temperature for 10 seconds. After holding, the wire is slowly cooled to room temperature in the furnace to obtain the finished tungsten heating wire.

[0060] The finished tungsten heating wire prepared in this comparative example was installed in the same MOCVD equipment as in the example, and its service life was tested at an operating temperature of 1500℃~2000℃.

[0061] Comparative Example 2 This comparative example provides a method for preparing a tungsten heating wire. Steps 1 and 3 in this comparative example are the same as in the embodiment, except that step 2 uses an alkaline washing treatment. The alkaline washing step is as follows: the shaped tungsten heating wire is immersed in a 5% sodium hydroxide solution at a solution temperature of 60°C for 15 minutes. After alkaline washing, it is ultrasonically cleaned with deionized water to remove residual alkaline solution and reaction byproducts from the surface.

[0062] The finished tungsten heating wire prepared in this comparative example was installed in the same MOCVD equipment as in the example, and its service life was tested at an operating temperature of 1500℃~2000℃.

[0063] Comparative Example 3 This comparative example provides a method for preparing a tungsten heating wire. Steps 1 and 2 in this comparative example are the same as in the example. The difference is that in step 3, a box annealing is used with a heating rate of 10℃ / min, raising the temperature from room temperature to 1600℃, and holding it at that temperature for 10 seconds. After the holding period, the wire is slowly cooled to room temperature in the furnace to obtain the finished tungsten heating wire.

[0064] The finished tungsten heating wire prepared in this comparative example was installed in the same MOCVD equipment as in the example, and its service life was tested at an operating temperature of 1500℃~2000℃. Test results: The actual machine service life of the tungsten heating wire prepared in the example reached 4650 hours. Figure 5 As shown, no problems such as melting, significant deformation, or a significant decrease in temperature uniformity occurred during the entire service life. The actual machine service life of the tungsten heating wires prepared in Comparative Examples 1-3 were 900h, 1200h, and 1800h, respectively. Figure 6-8 As shown, during the test, the tungsten heating wires of Comparative Examples 1-3 showed obvious deformation, and the tungsten heating wire of Comparative Example 1 eventually melted and became unusable due to local overheating.

[0065] In summary, this invention involves electrolytically cleaning a shaped tungsten heating wire with a bent structure in an alkaline electrolyte. This electrolytic cleaning precisely removes the dense oxide layer from the bent structure and stress concentration areas, providing a uniform pretreatment foundation for subsequent rapid heating annealing. The electrolytically cleaned shaped tungsten heating wire undergoes rapid heating annealing, utilizing its own eddy currents for heating. This allows the annealing temperature to be reached in a very short time. The rapid heating and instantaneous holding ensure that the internal stress generated by bending is fully eliminated while preventing the tungsten material from remaining in the high-temperature zone for an extended period. This inhibits recrystallization and abnormal grain growth of the tungsten material, effectively suppressing creep deformation at high temperatures and improving the high-temperature stability of the tungsten heating wire. This invention combines electrolytic cleaning and rapid heating annealing to produce a finished tungsten heating wire with a service life of over 4500 hours, which is more than 4.5 times longer than existing tungsten heating wires. This reduces downtime of MOCVD equipment due to tungsten heating wire replacement, enabling the equipment to operate stably for a long time, thereby improving the overall utilization rate of MOCVD equipment and wafer production efficiency.

[0066] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0067] In the description of this invention, it should be understood that the terms "center," "height," "thickness," "upper," "lower," "vertical," "horizontal," "top," "bottom," "inner," "outer," "axial," "radial," and "circumferential," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0068] In the description of this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0069] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0070] Although the present invention has been described in detail through the preferred embodiments above, it should be understood that the above description should not be considered as a limitation of the present invention. Various modifications and substitutions to the present invention will be apparent to those skilled in the art after reading the above description. Therefore, the scope of protection of the present invention should be defined by the appended claims.

Claims

1. A method for preparing a tungsten heating wire, characterized in that, Include: A molded tungsten heating wire is provided, the molded tungsten heating wire comprising at least a bending structure; Electrolytic cleaning step: The shaped tungsten heating wire is placed in an electrolyte for electrolytic cleaning to at least remove the oxide layer; Annealing process: The shaped tungsten heating wire after electrolytic cleaning is annealed to obtain the tungsten heating wire; In the annealing process, the heating rate is 40℃ / s~50℃ / s and the heating temperature is 1400℃~1600℃.

2. The preparation method according to claim 1, characterized in that, In the electrolytic cleaning step, the electrolyte is an alkaline electrolyte.

3. The preparation method according to claim 2, characterized in that, The alkaline electrolyte contains at least one of sodium hydroxide, sodium carbonate, and sodium dodecyl sulfate.

4. The preparation method according to claim 2, characterized in that, The alkaline electrolyte comprises sodium hydroxide, sodium carbonate, sodium dodecyl sulfate, and deionized water; wherein the mass concentration of sodium hydroxide is 13% to 23%, the mass concentration of sodium carbonate is 1% to 11%, and the mass concentration of sodium dodecyl sulfate is 0.3% to 1.3%.

5. The preparation method according to claim 1, characterized in that, In the electrolytic cleaning step, the current density is 0.6 A / dm³. 2 ~1.0A / dm 2 The electrolytic cleaning time is 4 to 6 minutes, and the temperature is 40℃ to 50℃.

6. The preparation method according to claim 1, characterized in that, The annealing process is induction annealing.

7. The preparation method according to claim 1, characterized in that, In the annealing process, the holding time is 10s to 30s.

8. The preparation method according to claim 1, characterized in that, The annealing process is carried out in a hydrogen atmosphere.

9. The preparation method according to claim 1, characterized in that, In the annealing process, the cooling rate is 15℃ / s to 25℃ / s.

10. The preparation method according to claim 1, characterized in that, After the electrolytic cleaning step and before the annealing step, the process further includes cleaning the shaped tungsten heating wire after electrolytic cleaning with deionized water and anhydrous ethanol.

11. The preparation method according to claim 1, characterized in that, The bending structure is obtained by bending a doped tungsten wire at a high temperature of 500℃~600℃.

12. A tungsten heating wire, characterized in that, The tungsten heating wire is prepared by the preparation method described in any one of claims 1 to 11.

13. The tungsten heating wire as described in claim 12, characterized in that, The diameter of the tungsten heating wire is 0.5mm to 1.0mm.

14. The preparation method according to claim 12, characterized in that, The operating temperature of the tungsten heating wire is 1500℃~2000℃.

15. A vapor deposition apparatus, characterized in that, The vapor deposition apparatus includes at least: reaction chamber; A substrate carrier stage, which is located within the reaction chamber; A heating assembly is located below the substrate support stage and is vertically spaced a distance from the substrate support stage; the heating assembly includes a main heater and an auxiliary heater, the auxiliary heater comprising a tungsten heating wire as described in any one of claims 12 to 14.

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