Vanadium oxide etching post-processing method based on VHF wetting driving

Abstract

The invention belongs to the technical field of infrared focal plane sensor manufacturing, and particularly relates to a vanadium oxide etching post-processing method based on VHF wetting driving. Comprising the following steps: performing graded vacuumizing and temperature programming pretreatment on a wafer subjected to vanadium oxide etching, and continuously introducing VHF moistening mixed gas consisting of anhydrous hydrogen fluoride, ethanol steam and inert carrier gas into a treatment cavity; by accurately regulating and controlling the temperature and pressure of the cavity, anhydrous hydrogen fluoride is promoted to be subjected to a selective fluorination reaction with photoresist decomposition products and metal impurities left after etching to generate gaseous products, and ethanol steam synchronously exerts the dual effects of moistening, corrosion prevention and water molecule desorption promotion. According to the method, a gas phase processing mode is adopted in the whole process, liquid intervention is avoided, the problems of vanadium oxide pixel adhesion and film corrosion can be effectively solved, meanwhile, residual impurities are thoroughly removed, the electrical property stability of the vanadium oxide film is guaranteed, the yield and detection precision of the infrared focal plane sensor are remarkably improved, and the method has good industrial application prospects.

Description

Technical Field

[0001] This invention belongs to the field of infrared focal plane sensor manufacturing technology, and specifically relates to a post-etching treatment method for vanadium oxide based on VHF lubrication drive. Background Technology

[0002] Vanadium oxide (VO) x Vanadium oxide thin films, with their excellent temperature coefficient of resistance (TCR) and low noise characteristics, have become the preferred material for fabricating the core thermistor unit of uncooled infrared focal plane array sensors. In the mass production process of infrared focal plane array sensors, the patterning etching of vanadium oxide thin films is a key step in forming arrayed pixel units. Currently, the mainstream etching process is dry etching, specifically including reactive ion etching (RIE) and inductively coupled plasma etching (ICP). However, after these etching processes, a large amount of etching byproducts, polymer residues, and ionic impurities easily remain on the surface of the vanadium oxide thin film and in the pixel gaps. These contaminants not only significantly increase the surface roughness of the thin film but also damage the inherent crystal structure of the vanadium oxide thin film, directly leading to a decrease in the temperature coefficient of resistance, a reduction in response rate, and noise signal superposition in the sensor device, ultimately severely degrading the device's detection sensitivity and long-term operational stability.

[0003] Currently, publicly available vanadium oxide etching post-treatment technologies are mainly divided into two categories: one is wet cleaning process, which usually involves immersion in acid or alkaline solutions or organic solvents, supplemented by ultrasonic vibration to remove residual adhesive. However, due to the limitation of solution interfacial tension, it has the inherent defect of incomplete removal of residual adhesive, and acid or alkaline solutions can easily cause chemical corrosion to the vanadium oxide film, resulting in irreversible degradation of the film's thermal sensitivity. The other is plasma cleaning process, which removes contaminants by bombarding the film surface with radio frequency (RF) plasma. However, RF plasma has the problem of concentrated energy distribution, resulting in incomplete removal of residual adhesive and easily inducing lattice defects in the vanadium oxide film. At the same time, its cleaning intensity is difficult to control precisely, and it cannot adapt to the post-treatment requirements of films under different etching process parameters.

[0004] In summary, existing post-processing technologies cannot simultaneously meet the dual requirements of contaminant removal efficiency and thin film performance protection. Therefore, there is an urgent need to develop a vanadium oxide etching post-processing method that is non-destructive, efficient, and controllable, so as to thoroughly remove contaminants from the thin film surface while ensuring that the original thermosensitive properties of the vanadium oxide thin film are not damaged, thereby meeting the mass production requirements of high-performance infrared focal plane sensors. Summary of the Invention

[0005] To address the common technical challenges in existing vanadium oxide etching post-processing methods, such as edge corrosion of vanadium oxide films, pixel array adhesion, difficulty in completely removing etching residues (including polymer residues and fluoride byproducts), and subsequent device electrical performance drift and poor long-term stability, this invention aims to provide a VHF lubrication-driven vanadium oxide etching post-processing method for infrared focal plane array sensors. This invention constructs a processing system that synergistically integrates a VHF electric field and a lubrication medium, precisely controlling electric field parameters, lubrication atmosphere, and temperature-pressure coupling conditions. This achieves efficient desorption and removal of etching residues while effectively suppressing surface damage to the vanadium oxide film, ensuring film surface flatness and stoichiometric stability, thereby significantly improving the mass production yield and detection accuracy of infrared focal plane array sensors.

[0006] To address the aforementioned technical problems, this invention provides a VHF-lubrication-driven vanadium oxide etching post-processing method, comprising:

[0007] Pre-processing stage: The wafers after vanadium oxide etching are subjected to graded vacuuming and programmed temperature rise pre-processing to avoid damage to the vanadium oxide pixel structure caused by vacuum abrupt changes and thermal stress.

[0008] The VHF lubrication system introduction stage involves continuously introducing a VHF lubrication mixture consisting of anhydrous hydrogen fluoride, ethanol vapor, and inert carrier gas into the processing chamber.

[0009] The lubrication-driven reaction stage involves precisely controlling the temperature and pressure of the chamber to induce anhydrous hydrogen fluoride to undergo a selective fluorination reaction with the photoresist decomposition products and metal impurities remaining after etching, generating gaseous products. Ethanol vapor simultaneously plays a dual role in lubrication, corrosion prevention, and promoting the desorption of water molecules.

[0010] Gradient desorption stage: The reaction products and unreacted gases are fully desorbed by adjusting the gas composition using a gradient.

[0011] Post-purification stage: The purification process is completed after multiple cycles of vacuuming and nitrogen filling.

[0012] Preferably, the pretreatment stage specifically includes the following steps: placing the wafer with completed vanadium oxide etching into the VHF processing chamber, closing the chamber and performing a step-by-step vacuuming process to reduce the pressure inside the chamber to 5-10 Torr; simultaneously raising the chamber temperature to 35-45°C at a programmed temperature rise rate of 2-3°C / min and holding it at this temperature for 10-15 minutes; the specific steps of the step-by-step vacuuming process are: first, evacuating to 50 Torr at a rate of 10 Torr / min, and then evacuating to the target pressure at a rate of 5 Torr / min.

[0013] Preferably, the VHF lubrication system introduction stage specifically includes the following steps: continuously introducing a VHF lubrication mixture into the VHF processing chamber, the VHF lubrication mixture consisting of 5-8% anhydrous hydrogen fluoride by volume, 3-5% ethanol vapor by volume, and the remainder being an inert carrier gas; controlling the flow rate of the VHF lubrication mixture to 80-120 sccm, maintaining the pressure inside the chamber at 20-30 Torr, and continuously ventilating for 5-8 minutes.

[0014] Preferably, the inert carrier gas is either nitrogen or argon, or a mixture of nitrogen and argon in a volume ratio of 1:1; the purity of the anhydrous hydrogen fluoride is ≥99.99%; and the ethanol vapor is generated by vaporizing anhydrous ethanol at 60-70°C.

[0015] Preferably, the lubrication-driven reaction stage specifically includes the following steps: adjusting the chamber temperature to 45-55℃, maintaining the chamber pressure at 20-30 Torr, maintaining the continuous flow of VHF lubrication mixture gas, and carrying out the lubrication-driven reaction for 15-25 minutes.

[0016] Preferably, during the lubrication-driven reaction, the intensity of the characteristic peaks of the fluorine-based gaseous products in the chamber is monitored in real time using an infrared spectrometer. When the intensity of the characteristic peaks stabilizes within ±3%, the reaction is determined to have reached equilibrium.

[0017] Preferably, the gradient desorption stage specifically includes the following steps: keeping the chamber temperature constant, and performing gradient adjustment on the components of the VHF lubricating mixed gas; first, reducing the volume fraction of anhydrous hydrogen fluoride to 2-3% and the volume fraction of ethanol vapor to 1-2%, maintaining this state for 5 minutes; then reducing the volume fractions of both anhydrous hydrogen fluoride and ethanol vapor to 0, and only introducing inert carrier gas into the chamber, maintaining this state for 5-8 minutes; during this gradient adjustment process, the pressure inside the chamber is gradually reduced to 10-15 Torr.

[0018] Preferably, the inert carrier gas flow rate is kept constant, and the volume fractions of anhydrous hydrogen fluoride and ethanol vapor are adjusted by regulating the supply rate of anhydrous hydrogen fluoride and the vaporization rate of ethanol vapor.

[0019] Preferably, the post-purification stage specifically includes the following steps: stopping the introduction of all gas into the cavity, performing a second vacuum treatment on the cavity to reduce the pressure inside the cavity to 1-3 Torr, and maintaining this pressure state for 3-5 minutes; then introducing high-purity nitrogen into the cavity to restore the cavity pressure to atmospheric pressure; repeating the above vacuum-nitrogen filling cycle 2-3 times, and removing the wafer after the purification operation is completed.

[0020] Preferably, the purity of the high-purity nitrogen gas is ≥99.999%; the secondary vacuuming is performed using a molecular pump with a vacuuming rate of 2 Torr / min.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] 1. This invention uses VHF lubrication driving technology to replace the traditional wet post-processing process. There is no liquid intervention throughout the process, which fundamentally avoids the problem of vanadium oxide pixel adhesion caused by liquid surface tension. At the same time, it eliminates the corrosion of the vanadium oxide film by the cleaning solution, ensures the structural integrity of the vanadium oxide pixel array, and significantly improves the yield of the sensor.

[0023] 2. This invention optimizes the composition and ratio of the VHF lubricating mixed gas and introduces ethanol vapor as a lubricant. On the one hand, it reduces the contact energy between anhydrous hydrogen fluoride and vanadium oxide film, avoiding excessive etching of the vanadium oxide film by anhydrous hydrogen fluoride and ensuring the lattice integrity and thermoelectric properties of the vanadium oxide film. On the other hand, ethanol vapor forms an azeotrope with water molecules, a reaction byproduct, promoting rapid desorption of water molecules and solving the performance drift problem caused by residual moisture in traditional processes.

[0024] 3. The present invention sets up a gradient desorption stage and a post-purification process of multiple vacuuming and nitrogen filling, which can thoroughly remove the gaseous fluorides generated in the reaction, unreacted lubricating gases and residual impurities, ensuring the cleanliness of the vanadium oxide film surface.

[0025] 4. This invention avoids the impact of sudden changes in process parameters on the vanadium oxide thin film and pixel structure through refined process control such as staged vacuuming, programmed temperature rise, and gradient gas regulation, thus further ensuring the performance stability of the sensor. At the same time, the entire post-processing process can be seamlessly integrated with the existing vanadium oxide etching process without the need for additional complex equipment, and has good prospects for industrial application. Attached Figure Description

[0026] Figure 1 The infrared focal plane array sensor provided by this invention is vanadium oxide (VO2) x A schematic diagram showing the structure of a large number of etching byproducts remaining on the surface after thin film etching.

[0027] Figure 2 This is a schematic diagram of the process flow for the VHF lubrication-driven vanadium oxide etching post-processing method for infrared focal plane sensors provided by the present invention.

[0028] Figure 3 After being processed using the VHF lubrication-driven post-processing method of this invention, the vanadium oxide (VO2) of the infrared focal plane sensor... x A schematic diagram of the structure in which residual etching byproducts on the etched surface are removed.

[0029] In the figure: 1-Etching byproducts, 2-VO x . Detailed Implementation

[0030] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. The advantages and features of the present invention will become clearer from the following description. It should be noted that the drawings are all in a very simplified form and use non-precise proportions, and are only used to facilitate and clarify the illustration of the embodiments of the present invention.

[0031] like Figures 1-3 As shown, this embodiment of the invention specifically provides a post-etching processing method for vanadium oxide in a VHF-lubricated infrared focal plane array sensor, which includes the following steps:

[0032] Step S1: Preprocessing stage;

[0033] The vanadium oxide etched wafer is placed in a VHF processing chamber. After the chamber is closed, a vacuum process is performed to reduce the pressure inside the chamber to 5-10 Torr. Simultaneously, the chamber temperature is raised to 35-45°C and held at this temperature for 10-15 minutes. The vacuum process employs a staged vacuum mode, specifically as follows: first, the pressure is evacuated to 50 Torr at a rate of 10 Torr / min, and then evacuated to the target pressure at a rate of 5 Torr / min. This mode effectively avoids sudden changes in vacuum level that could impact the vanadium oxide pixel structure.

[0034] Step S2: VHF lubrication system introduction stage;

[0035] A VHF lubricating mixed gas is continuously introduced into the VHF processing chamber. The VHF lubricating mixed gas consists of anhydrous hydrogen fluoride (HF), ethanol vapor, and an inert carrier gas. The volume percentages of each component are: anhydrous hydrogen fluoride 5-8%, ethanol vapor 3-5%, and the remainder is inert carrier gas. The flow rate of the mixed gas is controlled at 80-120 sccm, and the pressure inside the chamber is maintained at 20-30 Torr. The gas is continuously introduced for 5-8 minutes to ensure that the lubricating mixed gas fully fills the interior of the chamber and is uniformly adsorbed on the surface of the vanadium oxide film and the surface of the etching residue impurities, thus laying the foundation for the subsequent lubrication-driven reaction.

[0036] Step S3: Lubrication-driven reaction stage;

[0037] The chamber temperature is adjusted to 45-55℃, and the chamber pressure is kept stable at 20-30 Torr. A continuous flow of VHF lubricating gas mixture is maintained for 15-25 minutes to drive the lubrication reaction. During this process, anhydrous hydrogen fluoride reacts with the photoresist decomposition products and metallic impurities remaining after etching, generating volatile gaseous fluorides. Ethanol vapor plays a synergistic role in lubrication and protection: on the one hand, it reduces the contact energy between anhydrous hydrogen fluoride and the vanadium oxide film surface, effectively preventing excessive corrosion of the vanadium oxide film; on the other hand, it forms an azeotrope with the water molecules generated in the reaction, accelerating water molecule desorption. The inert carrier gas dilutes the reactant concentration and evenly distributes the gas flow field within the chamber, ensuring the reaction proceeds uniformly within the wafer.

[0038] Step S4: Gradient desorption stage;

[0039] To maintain a constant chamber temperature, the volume fractions of anhydrous hydrogen fluoride and ethanol vapor in the VHF lubricating gas mixture are gradually reduced by adjusting the gas source parameters, while the volume fraction of inert carrier gas is correspondingly increased, thus constructing a gradient desorption gas system. The specific gradient adjustment process is as follows: In the first stage, the volume fraction of anhydrous hydrogen fluoride is reduced to 2-3%, and the volume fraction of ethanol vapor is reduced to 1-2%, maintaining this state for 5 minutes. In the second stage, the volume fractions of anhydrous hydrogen fluoride and ethanol vapor are further reduced to 0, with only inert carrier gas introduced, maintaining this state for 5-8 minutes. During this gradient adjustment process, the pressure inside the chamber is simultaneously and gradually reduced to 10-15 Torr to ensure that the gaseous products generated in the reaction and the unreacted lubricating gas are fully desorbed and completely discharged from the chamber.

[0040] Step S5: Post-purification stage;

[0041] Stop all gas supply and perform a second vacuuming process on the cavity to reduce the pressure inside the cavity to 1-3 Torr, and maintain this vacuum level for 3-5 minutes. Then, introduce high-purity nitrogen into the cavity to restore the cavity pressure to atmospheric pressure. Repeat the above vacuuming-nitrogen filling cycle 2-3 times. After completion, perform purification treatment. Finally, open the cavity and take out the post-processed wafer.

[0042] Furthermore, in step S1, the cavity heating process adopts a programmed heating mode, with a heating rate set at 2-3℃ / min. This slow heating method ensures that the temperature of each area of ​​the vanadium oxide film increases uniformly, avoiding local thermal stress concentration that could lead to film cracking.

[0043] Furthermore, in step S2, the inert carrier gas is either nitrogen or argon, or a mixture of nitrogen and argon in a volume ratio of 1:1; the purity of the anhydrous hydrogen fluoride is ≥99.99% to ensure the efficiency of the fluorination reaction and avoid introducing impurities; the ethanol vapor is generated by heating anhydrous ethanol to 60-70℃ and vaporizing it. This vaporization process ensures that there is no residual moisture in the ethanol vapor, preventing moisture from adversely affecting the thermosensitive properties of the vanadium oxide film.

[0044] Furthermore, in step S3, during the lubrication-driven reaction, the intensity of the characteristic peaks of the gaseous products in the cavity is monitored in real time using an infrared spectrometer through an online monitoring window set on the side wall of the cavity; when the intensity of the characteristic peaks of the fluorine-based gaseous substances is monitored to be stable within ±3%, it can be determined that the lubrication-driven reaction has reached equilibrium.

[0045] Furthermore, in step S4, the inert carrier gas flow rate is kept constant, and the gradient controllable adjustment of the volume fraction of anhydrous hydrogen fluoride and ethanol vapor in the mixed gas is achieved by precisely adjusting the supply rate of anhydrous hydrogen fluoride and the vaporization rate of ethanol vapor.

[0046] Furthermore, in step S5, the purity of the high-purity nitrogen gas is ≥99.999% to avoid introducing new impurities during the purification process; the secondary vacuuming is completed using a molecular pump, with the vacuuming rate set at 2 Torr / min to ensure a stable and efficient vacuuming process.

[0047] The present invention will be further described in detail below with reference to specific embodiments, but the scope of protection of the present invention is not limited to the following embodiments.

[0048] Example 1

[0049] A VHF-lubricated post-etching processing method for vanadium oxide in an infrared focal plane array sensor, comprising the following specific steps:

[0050] Step 1: Preprocessing stage;

[0051] The wafer with completed vanadium oxide etching is placed stably in the VHF processing chamber. After the chamber is closed, the vacuum system is started and the vacuum operation is performed in a stepped vacuum mode: first, the vacuum is pumped at a rate of 10 Torr / min to 50 Torr, and then switched to a rate of 5 Torr / min to 8 Torr. At the same time, the chamber temperature control module is started to raise the chamber temperature to 40°C at a programmed temperature increase rate of 2°C / min and hold it at that temperature for 12 minutes to complete the pretreatment.

[0052] Step 2: VHF lubrication system introduction stage;

[0053] A VHF lubricating mixed gas is continuously introduced into the VHF processing chamber. The components and volume fractions of the mixed gas are as follows: 6% anhydrous hydrogen fluoride (purity ≥99.99%), 4% ethanol vapor (generated by heating anhydrous ethanol to 65°C to vaporize, ensuring no moisture residue), and 90% nitrogen. The flow rate of the mixed gas is precisely controlled to 100 sccm using a flow controller to maintain a stable pressure of 25 Torr in the chamber. The gas is continuously introduced for 6 minutes to ensure that the lubricating mixed gas evenly covers and adsorbs onto the surface of the vanadium oxide film and the surface of etching residue impurities.

[0054] Step 3: Lubrication-driven reaction stage;

[0055] Adjust the chamber temperature control module to raise the chamber temperature to 50°C, maintain the chamber pressure at 25 Torr, and maintain the continuous flow of VHF lubricating mixed gas to carry out the lubrication-driven reaction for 20 minutes. During the reaction, use an infrared spectrometer mounted on the online monitoring window on the side wall of the chamber to monitor the characteristic peak intensity of the fluorine gaseous products in the chamber in real time. When the characteristic peak intensity is found to be stable within ±3%, continue the reaction at the temperature for 5 minutes, and then proceed to the next step.

[0056] Step 4: Gradient desorption stage;

[0057] Maintain a constant chamber temperature of 50°C, and gradually adjust the component ratio of the VHF lubricating gas mixture through the gas source control system: In the first stage, reduce the volume fraction of anhydrous hydrogen fluoride to 2.5% and the volume fraction of ethanol vapor to 1.5%, and maintain this state for 5 minutes; in the second stage, further reduce the volume fraction of anhydrous hydrogen fluoride and ethanol vapor to 0, and continuously introduce nitrogen gas, and maintain this state for 6 minutes; during this gradient adjustment process, simultaneously control the vacuum system to gradually reduce the pressure inside the chamber to 12 Torr, ensuring that the gaseous fluoride generated by the reaction and the lubricating gas that did not participate in the reaction are fully desorbed and discharged from the chamber.

[0058] Step 5: Post-purification stage;

[0059] Stop all gas supply and use a molecular pump to perform a secondary vacuum treatment on the cavity, setting the vacuum rate to 2 Torr / min, so that the pressure in the cavity drops to 2 Torr and maintains this vacuum level for 4 minutes; then introduce high-purity nitrogen gas with a purity ≥99.999% into the cavity to restore the cavity pressure to atmospheric pressure, and repeat the above vacuum-nitrogen filling purification cycle twice, and then purify; finally, open the cavity and take out the post-processed wafer.

[0060] Example 2

[0061] A VHF-lubricated post-etching processing method for vanadium oxide in an infrared focal plane array sensor includes the following steps:

[0062] Step 1: Preprocessing stage;

[0063] The wafer with vanadium oxide etching completed is placed in the VHF processing chamber. After the chamber is closed, a step-by-step vacuuming operation is performed: first, the vacuum is pumped to 50 Torr at a rate of 10 Torr / min, and then to 5 Torr at a rate of 5 Torr / min. At the same time, the chamber temperature is raised to 35°C at a programmed temperature rise rate of 3°C / min and held at this temperature for 10 min.

[0064] Step 2: VHF lubrication system introduction stage;

[0065] A VHF lubricating mixed gas is continuously introduced into the VHF processing chamber. The mixed gas consists of 5% anhydrous hydrogen fluoride (99.99% purity), 3% ethanol vapor (generated by vaporizing anhydrous ethanol at 60°C), and 92% argon. The flow rate of the mixed gas is controlled at 80 sccm, and the pressure inside the chamber is maintained at 20 Torr by a pressure control system. The gas is continuously introduced for 5 minutes to ensure that the mixed gas fully fills the chamber and adsorbs onto the target surface.

[0066] Step 3: Lubrication-driven reaction stage;

[0067] The chamber temperature was adjusted to 45°C using the chamber temperature control system, and the pressure inside the chamber was kept stable at 20 Torr. The VHF lubricating mixed gas was continuously introduced, and the lubrication-driven reaction was carried out for 15 minutes. During the reaction, the characteristic peak intensity of the fluorine gaseous products inside the chamber was monitored in real time using an infrared spectrometer through the online monitoring window on the side wall of the chamber. When the characteristic peak intensity was stable within ±3%, the reaction was continued for another 3 minutes before proceeding to the next step.

[0068] Step 4: Gradient desorption stage;

[0069] Maintain a constant chamber temperature of 45°C and perform gradient regulation on the VHF lubricating mixed gas components: In the first stage, reduce the volume fraction of anhydrous hydrogen fluoride to 2% and the volume fraction of ethanol vapor to 1%, and maintain this state for 5 minutes; In the second stage, continue to reduce the volume fraction of anhydrous hydrogen fluoride and ethanol vapor to 0, and only introduce argon gas into the chamber, and maintain this state for 5 minutes; During this gradient regulation process, simultaneously reduce the pressure in the chamber to 10 Torr to ensure that gaseous products and unreacted gases are fully desorbed and discharged.

[0070] Step 5: Post-purification stage;

[0071] Stop introducing all gases into the chamber, and use a molecular pump to perform a second vacuuming process at a vacuum rate of 2 Torr / min to reduce the pressure inside the chamber to 1 Torr, maintaining this pressure for 3 minutes; then introduce high-purity nitrogen gas (99.999% purity) into the chamber to restore the chamber pressure to atmospheric pressure; repeat the above vacuuming-nitrogen filling cycle twice, and then perform the purification operation; finally, open the chamber and remove the post-processed wafer.

[0072] Example 3

[0073] A VHF-lubricated post-etching processing method for vanadium oxide in an infrared focal plane array sensor includes the following steps:

[0074] Step 1: Preprocessing stage;

[0075] The wafer with vanadium oxide etching completed is placed in the VHF processing chamber. After the chamber is closed, a step-by-step vacuuming operation is performed: first, the vacuum is pumped to 50 Torr at a rate of 10 Torr / min, and then to 10 Torr at a rate of 5 Torr / min. At the same time, the chamber temperature is raised to 45°C at a programmed temperature rise rate of 2.5°C / min and held at this temperature for 15 minutes.

[0076] Step 2: VHF lubrication system introduction stage;

[0077] A VHF lubricating mixed gas is continuously introduced into the VHF processing chamber. The mixed gas consists of: 8% by volume anhydrous hydrogen fluoride (99.99% purity), 5% by volume ethanol vapor (generated by vaporization of anhydrous ethanol heated to 70°C), and 87% by volume nitrogen-argon mixed gas (nitrogen to argon volume ratio 1:1). The flow rate of the mixed gas is controlled at 120 sccm, and the pressure in the chamber is maintained at 30 Torr by a pressure control system. The gas is continuously introduced for 8 minutes to ensure that the mixed gas fully fills the chamber and adsorbs onto the target surface.

[0078] Step 3: Lubrication-driven reaction stage;

[0079] The chamber temperature was adjusted to 55°C using the chamber temperature control system, and the chamber pressure was kept stable at 30 Torr. The VHF lubricating mixed gas was continuously introduced, and the lubrication-driven reaction was carried out for 25 minutes. During the reaction, the characteristic peak intensity of the fluorine gaseous products in the chamber was monitored in real time using an infrared spectrometer through the online monitoring window on the side wall of the chamber. When the characteristic peak intensity was stable within ±3%, the reaction was continued for another 5 minutes before proceeding to the next step.

[0080] Step 4: Gradient desorption stage;

[0081] Maintain a constant chamber temperature of 55°C and perform gradient regulation on the VHF lubricating mixed gas components: In the first stage, reduce the volume fraction of anhydrous hydrogen fluoride to 3% and the volume fraction of ethanol vapor to 2%, and maintain this state for 5 minutes; In the second stage, continue to reduce the volume fraction of anhydrous hydrogen fluoride and ethanol vapor to 0, and only introduce nitrogen-argon mixed gas into the chamber, and maintain this state for 8 minutes; During this gradient regulation process, simultaneously reduce the pressure in the chamber to 15 Torr to ensure that gaseous products and unreacted gases are fully desorbed and discharged.

[0082] Step 5: Post-purification stage;

[0083] Stop introducing all gases into the chamber, and use a molecular pump to perform a second vacuuming process at a vacuum rate of 2 Torr / min to reduce the pressure inside the chamber to 3 Torr, maintaining this pressure for 5 minutes; then introduce high-purity nitrogen gas (99.999% purity) into the chamber to restore the chamber pressure to atmospheric pressure; repeat the above vacuuming-nitrogen filling cycle 3 times, and then perform the purification operation; finally, open the chamber and remove the post-processed wafer.

[0084] The above description is merely a description of preferred embodiments of the present invention and is not intended to limit the scope of the present invention in any way. Any changes or modifications made by those skilled in the art based on the above disclosure shall fall within the protection scope of the claims.

Claims

1. A post-etching treatment method for vanadium oxide based on VHF lubrication-driven etching, characterized in that, include: Preprocessing stage; By performing graded vacuuming and programmed temperature pretreatment on the wafer after vanadium oxide etching, damage to the vanadium oxide pixel structure caused by vacuum abrupt changes and thermal stress can be avoided. The VHF lubrication system introduction stage involves continuously introducing a VHF lubrication mixture consisting of anhydrous hydrogen fluoride, ethanol vapor, and inert carrier gas into the processing chamber. The lubrication-driven reaction stage involves precisely controlling the temperature and pressure of the chamber to induce anhydrous hydrogen fluoride to undergo a selective fluorination reaction with the photoresist decomposition products and metal impurities remaining after etching, generating gaseous products. Ethanol vapor simultaneously plays a dual role in lubrication, corrosion prevention, and promoting the desorption of water molecules. Gradient desorption stage: The reaction products and unreacted gases are fully desorbed by adjusting the gas composition using a gradient. Post-purification stage: The purification process is completed after multiple cycles of vacuuming and nitrogen filling.

2. The vanadium oxide etching post-treatment method based on VHF lubrication-driven method as described in claim 1, characterized in that, The pretreatment stage specifically includes the following steps: placing the vanadium oxide etched wafer into the VHF processing chamber, closing the chamber, and performing a graded vacuum process to reduce the pressure inside the chamber to 5-10 Torr; simultaneously raising the chamber temperature to 35-45°C at a programmed temperature rise rate of 2-3°C / min, and holding at this temperature for 10-15 min; the specific steps of the graded vacuum process are: first, evacuating to 50 Torr at a rate of 10 Torr / min, and then evacuating to the target pressure at a rate of 5 Torr / min.

3. The vanadium oxide etching post-treatment method based on VHF lubrication-driven method as described in claim 1, characterized in that, The VHF lubrication system introduction stage specifically includes the following steps: continuously introducing a VHF lubrication mixture into the VHF processing chamber, the VHF lubrication mixture consisting of 5-8% anhydrous hydrogen fluoride, 3-5% ethanol vapor, and the remainder inert carrier gas; controlling the flow rate of the VHF lubrication mixture to 80-120 sccm, maintaining the pressure in the chamber at 20-30 Torr, and continuously ventilating for 5-8 minutes.

4. The vanadium oxide etching post-treatment method based on VHF lubrication-driven method as described in claim 3, characterized in that, The inert carrier gas is either nitrogen or argon, or a mixture of nitrogen and argon in a volume ratio of 1:1; the purity of the anhydrous hydrogen fluoride is ≥99.99%; the ethanol vapor is generated by vaporizing anhydrous ethanol at 60-70°C.

5. The vanadium oxide etching post-treatment method based on VHF lubrication-driven method as described in claim 1, characterized in that, The lubrication-driven reaction stage specifically includes the following steps: adjusting the chamber temperature to 45-55℃, maintaining the chamber pressure at 20-30 Torr, maintaining the continuous flow of VHF lubrication mixture gas, and carrying out the lubrication-driven reaction for 15-25 minutes.

6. The vanadium oxide etching post-treatment method based on VHF lubrication-driven method as described in claim 5, characterized in that, During the lubrication-driven reaction, the intensity of the characteristic peaks of the fluorine-based gaseous products in the chamber is monitored in real time using an infrared spectrometer. When the intensity of the characteristic peaks stabilizes within ±3%, the reaction is determined to have reached equilibrium.

7. The vanadium oxide etching post-treatment method based on VHF lubrication-driven method as described in claim 3, characterized in that, The gradient desorption stage specifically includes the following steps: keeping the chamber temperature constant, the components of the VHF lubricating mixed gas are adjusted in a gradient; first, the volume fraction of anhydrous hydrogen fluoride is reduced to 2-3% and the volume fraction of ethanol vapor is reduced to 1-2%, and this state is maintained for 5 minutes; then, the volume fractions of both anhydrous hydrogen fluoride and ethanol vapor are reduced to 0, and only inert carrier gas is introduced into the chamber, and this is maintained for 5-8 minutes; during this gradient adjustment process, the pressure in the chamber is gradually reduced to 10-15 Torr.

8. The vanadium oxide etching post-treatment method based on VHF lubrication-driven method as described in claim 7, characterized in that, The inert carrier gas flow rate is kept constant. The volume fractions of anhydrous hydrogen fluoride and ethanol vapor are adjusted by regulating the supply rate of anhydrous hydrogen fluoride and the vaporization rate of ethanol vapor.

9. The vanadium oxide etching post-treatment method based on VHF lubrication-driven method as described in claim 1, characterized in that, The post-purification stage specifically includes the following steps: stop introducing all gas into the cavity, perform a second vacuum treatment on the cavity to reduce the pressure inside the cavity to 1-3 Torr, and maintain this pressure state for 3-5 minutes; then introduce high-purity nitrogen into the cavity to restore the cavity pressure to atmospheric pressure; repeat the above vacuum-nitrogen filling cycle 2-3 times, and remove the wafer after the purification operation is completed.

10. The vanadium oxide etching post-treatment method based on VHF lubrication-driven method as described in claim 9, characterized in that, The purity of the high-purity nitrogen gas is ≥99.999%; the secondary vacuuming is performed using a molecular pump with a vacuuming rate of 2 Torr / min.

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