Inlet device for steady growth of VOx thin film based on fast response gas control

Abstract

The present application relates to sputtering film coating technical field, specifically to a kind of VOx film steady-state growth gas inlet device based on fast response gas control, for injecting reaction gas into the reaction cavity in VOx film sputtering system, reaction cavity is equipped with susceptor and heater arranged in the inside of susceptor, the gas inlet device includes: reaction gas delivery channel and gas inlet hole, delivery channel is connected with external gas source, reaction gas is delivered to reaction cavity, and delivery channel is arranged below susceptor;The gas inlet hole is arranged on susceptor mesa and is communicated with the delivery channel, and the distribution of multiple gas inlet holes on susceptor mesa is that the density of edge area below wafer is greater than the density of central area.The present application compensates the inherent deposition non-uniformity of wafer edge and center by non-uniform gas inlet hole, thereby improving the uniformity of film as a whole;By shortening gas delivery path, oxygen partial pressure adjustment rate is improved, target voltage fluctuation range is narrowed, and finally steady-state control is realized.

Description

Technical Field

[0001] This invention relates to the field of sputtering coating technology, and more specifically to a VOx thin film steady-state growth inlet device based on fast-response gas control. Background Technology

[0002] Reactive magnetron sputtering is one of the important methods for preparing VOx functional thin films. This technique usually involves introducing a reactive gas (such as oxygen) into a reaction chamber and bombarding a metal target with plasma, causing the sputtered target atoms to react chemically with the reactive gas on the surface of a substrate (such as a wafer) and deposit it into a film.

[0003] In existing technologies, the method of introducing and controlling the reactive gas has a decisive impact on the uniformity of the thin film. Currently, common gas supply methods often involve direct introduction or the use of simple oxygen rings. These methods tend to lead to uneven distribution of the reactive gas within the cavity, resulting in significant in-plane differences in parameters such as the thickness, chemical composition, and sheet resistance of the deposited film. This makes it difficult to meet the stringent uniformity requirements of high-performance devices.

[0004] To address the issue of thin film uniformity caused by uneven gas distribution, existing technologies have proposed several improvement solutions. For example, patent publication number CN117385331A discloses a device for improving the uniformity of vanadium dioxide thin films. This device improves the uniformity of oxygen distribution within the working space of the reaction chamber by circumferentially arranging multiple gas pipes within the inner liner and adjusting the position of the gas outlet by selecting gas pipes of different lengths or adding corrugated pipes. Furthermore, it adjusts the gas outlet direction by assembling elbows of different angles at the outlet, thereby improving the uniformity of oxygen distribution within the chamber's working space.

[0005] On the other hand, in terms of gas control, a closed-loop feedback control mechanism based on sputtering voltage feedback is typically employed. This control system utilizes the correlation between the "target poisoning" effect and the sputtering voltage—when oxygen is abundant, a high-resistivity V₂O₅ insulating layer forms on the target surface, leading to an increase in sputtering voltage; conversely, when oxygen is deficient, the target surface regains its metallic conductivity, and the voltage decreases. Based on this characteristic, the control system monitors voltage changes in real time and adjusts the oxygen flow rate accordingly to maintain a stable reaction process.

[0006] However, the inventors discovered that although solutions such as CN117385331A improve gas distribution uniformity by optimizing the gas input position and direction through the addition of a gas pipe structure within the cavity, they inevitably lengthen the gas path, exacerbating the inherent response lag and hysteresis effects of the gas control unit. From the issuance of the regulation command to the actual entry of the gas into the cavity and its effect on the plasma state, there is a significant mechanical and gas path transmission delay, leading to overshoot or undershoot in the regulation of the reactive gas flow rate, making it difficult to quickly stabilize the process state. Furthermore, the excessively long gas path further amplifies the system's hysteresis characteristics, causing significant differences in film characteristics with varying gas flow rates under the same oxygen partial pressure, increasing the difficulty of process debugging and the inhomogeneity of the film. Summary of the Invention

[0007] This invention provides a VOx thin film steady-state growth inlet device based on fast-response gas control, which aims to shorten the reaction gas loop and improve film uniformity.

[0008] To address the aforementioned problems, this invention provides a VOx thin film steady-state growth inlet device based on fast-response gas control, employing the following technical solution: A VOx thin film steady-state growth inlet device based on fast-response gas control is used to inject reactive gas into the reaction chamber of a VOx thin film sputtering system. The reaction chamber is equipped with a base and a heater disposed inside the base. The inlet device includes: A reaction gas delivery channel is provided, which is connected to an external reaction gas source to deliver reaction gas to the reaction chamber. The delivery channel is located below the base. Multiple air inlets are disposed on the base platform and connected to the conveying channel. The distribution of the multiple air inlets on the base platform is such that the density in the edge region below the wafer is greater than the density in the center region.

[0009] The vents beneath the wafer are designed with a differentiated layout: the density of vents around the perimeter is greater than that in the center. This results in greater ventilation at the wafer edges than at the center, enhancing gas convection at the edges and increasing the edge temperature through convective heat transfer. The higher temperature leads to increased oxygen precipitation at the edges, thereby reducing the sheet resistance (Rs) of the edge film. This compensates for the inherent deposition inhomogeneities at the wafer edges and center, thus improving overall film uniformity (the original uneven distribution with high Rs at the edges and low Rs at the center is transformed into a more uniform Rs distribution across the entire wafer by artificially raising the edge temperature and lowering the edge Rs).

[0010] The gas inlet is designed with a higher density at the edge of the substrate stage compared to the center, achieving a sophisticated gas-thermal-electric coupling control. This configuration allows for a significantly higher gas flow rate at the wafer edge compared to the center, enhancing convective heat transfer in the edge region. In a typical reactive sputtering process (where the substrate stage is heated), this leads to an unexpected effect: the higher-velocity, higher-temperature reactive gas has a stronger "heating" effect on the wafer edge, causing the edge temperature to be higher than the center, thus actively creating a controllable temperature gradient.

[0011] Artificially introduced temperature gradients can significantly alter the local chemical reactions of thin film deposition. High temperatures increase oxygen evolution at the edge of the film, forming a metal-rich vanadium oxide phase. These phases have low resistivity, which in turn reduces the sheet resistance (Rs) of the edge film.

[0012] By controlling the temperature field through non-uniform vias, the chemical composition and phase structure of thin films in different regions of the wafer can be actively modulated, ultimately achieving the trimming of the square resistance (Rs) distribution. This is a cross-disciplinary, high-level solution that controls thermal effects (temperature) through physical means (vias) to ultimately solve electrical problems (Rs uniformity).

[0013] Hysteresis and uniformity issues in reactive sputtering are long-standing challenges. Mainstream industry solutions involve improving active control (such as feedforward control, faster valves, and PID algorithm optimization) or creating a uniform airflow distribution above the wafer. This solution offers a completely different technical approach: a passive, hardware-based solution that avoids directly confronting the control loop. Instead, it takes a different, even counterintuitive, approach, actively introducing a controllable, non-uniform airflow distribution to compensate for the non-uniformity introduced by another physical process (deposition / reaction). It cleverly utilizes a series of physicochemical effects related to gas flow, convective heat transfer, and thin-film oxygen evolution.

[0014] It is generally believed that increasing the airflow will bring more reactive gases, which may lead to a decrease in thin film resistivity (due to increased metal phase or doping) or an increase (due to more complete oxidation), with uncertain results. However, this invention controls the local gas flow rate and velocity through "non-uniform openings," thereby changing the local convective heat transfer coefficient, increasing the local temperature, and achieving active control over the wafer airflow and temperature distribution, ultimately making the Rs distribution uniform throughout the entire wafer surface.

[0015] As a preferred embodiment of the present invention, the air inlet is configured as a blind hole, and its bottom is connected to the conveying channel through a transverse connecting hole.

[0016] As a preferred embodiment of the present invention, the air inlet is distributed in a multi-ring concentric circle, and the distribution density of the air inlet increases and / or the diameter increases from the inner ring to the outer ring.

[0017] As a preferred embodiment of the present invention, the depth of the air inlet is different in different concentric ring regions.

[0018] As a preferred embodiment of the present invention, the number of air inlets per unit area in the edge region of the base platform is 1.5-3 times that in the central region.

[0019] In a preferred embodiment of the present invention, at least a portion of the conveying channel is integrated inside the heater, and the conveying channel integrated inside the heater serves as a heating channel. By integrating a portion of the conveying channel inside the heater, not only is equipment space saved, but heat transfer efficiency is also enhanced, ensuring that the reaction gas reaches the required process temperature before entering the reaction chamber.

[0020] In a preferred embodiment of the present invention, a pneumatic valve is provided upstream of the heater in the airflow direction of the conveying channel. This arrangement of the pneumatic valve upstream of the heater in the airflow direction of the conveying channel enables rapid and precise control of the reaction gas flow rate. This ensures that the reaction gas can be switched on or adjusted before entering the heating zone, thereby improving the dynamic response capability of the process. This is particularly suitable for scenarios requiring rapid adjustment of the gas supply.

[0021] As a preferred embodiment of the present invention, it further includes a control unit, which controls a pneumatic valve located upstream of the heater according to the target voltage fluctuation, so as to adjust the flow rate of the reaction gas entering the internal delivery channel of the heater.

[0022] As a preferred embodiment of the present invention, the pneumatic valve is a fast-response valve.

[0023] More preferably, the fast-response valve is a piezoelectric valve or a voice coil valve.

[0024] In a preferred embodiment of the present invention, the reaction gas delivery channel includes two independent branches: a first branch and a second branch. The first branch supplies gas to the air inlet in the central region, and the second branch supplies gas to the air inlet in the edge region. Each branch is equipped with an independently adjustable flow valve. This achieves precise zonal control of the reaction gas delivery process. By dividing the delivery channel into two independent branches, corresponding to the air inlets in the central and edge regions respectively, and by providing independently adjustable flow valves on each branch, the gas flow distribution in different regions can be precisely adjusted according to actual process requirements.

[0025] As a preferred embodiment of the present invention, the air intake device is suitable for a magnetron sputtering system for vanadium oxide thin films.

[0026] The beneficial effects are: 1. This gas inlet device eliminates the long gas nozzle structure. Instead, the gas inlets are positioned on the substrate surface beneath the wafer, with a non-uniform density distribution of inlets at the edges compared to the center. This design shortens the gas delivery path and reduces the response time of the gas control loop, mitigating the response lag and hysteresis effects inherent in traditional long-path gas control and improving rapid and stable process control. Furthermore, the non-uniformly distributed inlets on the substrate surface deliver preheated, controllable reactive gases to compensate for differences in gas consumption rates across different areas of the wafer, resulting in a vanadium oxide thin film with uniform composition and sheet resistance. Specifically, increased gas flow at the wafer edges leads to stronger convection, causing temperatures to rise higher than in the center. This higher temperature results in higher oxygen evolution in the edge film compared to the center, significantly reducing Rs in the edge region.

[0027] 2. Use a heater to preheat the gas in the delivery channel to shorten the thermal response time of the reaction gas from flow rate adjustment to actual participation in the sputtering reaction. Attached Figure Description

[0028] Figure 1 A schematic cross-sectional view of the reaction chamber and the portion of the transport channel connected to the base; Figure 2 A schematic diagram of the base and part of the conveying channel; Figure 3 This is a cross-sectional view of the base (cross-sectional view of the uppermost transverse connecting hole layer). Figure 4 This is a schematic diagram of the oxygen gas control loop in the reaction sputtering process of a traditional long gas nozzle structure (hereinafter referred to as before the improvement); Figure 5 This is a schematic diagram of the oxygen gas control loop during the reactive sputtering process of the present invention; Figure 6 A schematic diagram of the characteristic curve of target surface voltage changing with time during the pre-reactive sputtering process; Figure 7 This is a schematic diagram of the characteristic curve of the target surface voltage changing with time during the reactive sputtering process of the present invention; Figure 8 To improve the distribution map of surface resistivity of the wafer; Figure 9 This is a map showing the distribution of surface resistance values ​​on the wafer of this invention.

[0029] Explanation of reference numerals in the attached figures: 1. Reaction chamber; 2. Base; 21. Air inlet; 22. Connecting hole; 3. Delivery channel. Detailed Implementation

[0030] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Those skilled in the art should understand that the embodiments described below are only some, not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0031] A traditional reactive sputtering system for growing VOx thin films includes a reaction chamber, a sputtering power source, and a vacuum system, a wafer transfer system, and a gas control unit, all connected to the reaction chamber. The gas control unit plays a crucial role in precisely supplying the reactive gases, strictly controlling their concentration within the reaction chamber.

[0032] A common gas control unit establishes a closed-loop control feedback mechanism by collecting sputtering voltage: this system utilizes the correlation between the "target poisoning" phenomenon and voltage—when oxygen is excessive, an insulating V₂O₅ layer forms on the vanadium target surface, causing a voltage increase (the resistivity of metallic vanadium is approximately 25 μΩ·cm, while V₂O₅ is as high as 10 μΩ·cm). 10 The insulating layer causes a surge in the equivalent impedance of the plasma interface (Ω·cm), requiring a higher voltage to maintain the discharge, necessitating a voltage increase in the power supply. Conversely, vanadium deposition in oxygen-deficient conditions lowers the voltage. Based on this characteristic, the PLC continuously compares the measured voltage in the reaction chamber with the desired value, dynamically adjusting the oxygen flow rate according to the comparison results to stabilize the sputtering at the target reaction state. The core value of this steady-state voltage control lies in its ability to indirectly maintain the dynamic balance of the vanadium-oxygen reaction, effectively preventing oxygen partial pressure runaway.

[0033] The aforementioned gas control mechanism can be directly applied to the magnetron sputtering preparation of vanadium oxide thin films: using metallic vanadium as the target material, the target voltage is changed by precisely controlling the oxygen flow rate, thereby generating a vanadium oxide thin film on the substrate. The gas delivery path is specifically as follows: oxygen is controlled in a chain from a gas cylinder → first pneumatic valve → vacuum valve (pressure regulating valve) → flow meter → second pneumatic valve, ultimately entering the reaction zone through multiple evenly distributed nozzles inside the cavity. When oxygen participates in the reaction, the oxygen concentration affects the target voltage change. This target voltage change triggers power supply voltage fluctuations, and the PLC then adjusts the gas flow meter in reverse based on the voltage monitoring value. The flow meter controls the oxygen input concentration, forming a closed-loop negative feedback gas control circuit.

[0034] However, the long-path feedback mechanism of this traditional gas control loop causes a double coupling problem in actual operation: Response lag: Due to the excessively long actual feedback path of the equipment, there is a mechanical delay, making it impossible to respond to dynamic reaction processes in real time. When the system detects that the oxygen partial pressure deviates from the target (such as a voltage drop indicating oxygen deficiency), the adjustment command needs to be transmitted over a long chain through the gas cylinder → pressure regulating valve → flow meter → pneumatic valve → nozzle. That is, there is a waiting time from the adjustment of oxygen flow rate to the change of plasma state. During this period, a conductive VO phase may be generated in a local area due to instantaneous oxygen deficiency, and then oxygen accumulation due to excessive oxygen enrichment will form high-resistivity V2O5. The response lag causes the plasma to be in an oscillating and uncontrolled state.

[0035] Reactive sputtering inherently exhibits a hysteresis effect, which is significantly amplified by long loops, causing the system to oscillate for a prolonged period in the "transition region" (near the target voltage range). The hysteresis effect refers to the fact that, in the relationship between the reactant gas flow rate and the oxygen partial pressure within the reaction chamber, the two curves showing the change in oxygen partial pressure (corresponding to the composition of the obtained vanadium oxide) with increasing / decreasing reactant gas flow rate do not coincide. Therefore, even if the reactant gas partial pressure within the reaction chamber is the same, the composition of the obtained vanadium oxide will differ depending on whether the reactant gas flow rate is increasing or decreasing. Decreasing the oxygen flow rate does not immediately cause the sputtering rate to return to a high level; instead, it exhibits a slow recovery, and even small changes in oxygen levels have a significant impact on the degree of oxidation.

[0036] Relationship between voltage and vanadium oxide valence state:

[0037] In summary, the gas delivery path is too long, resulting in a delayed response. Furthermore, the gas control unit has an inherent hysteresis effect. The combined effect of hysteresis and delay leads to continuous overshoot / undershoot of oxygen flow. The long loop also amplifies the inherent settling time of the gas control unit, resulting in a large fluctuation range when adjusting the target oxygen partial pressure, which in turn leads to low stability of the target voltage.

[0038] To address the aforementioned issues, this invention eliminates the long gas nozzle structure within the existing reaction chamber and integrates the reaction gas delivery channel inside the heater. This allows oxygen to be directly supplied into the chamber from below the wafer, thereby shortening the gas control loop path and reducing the response time of the control system. By reducing the residence time of the reaction gas in the transition zone, the goal of achieving stable control of the target surface voltage is ultimately achieved.

[0039] However, if the reactant gas is supplied directly through the vent at the bottom of the wafer, it will result in a high oxygen concentration at the wafer edge, generating high-valence VOx, and a large Rs in the wafer edge region; while the middle is oxygen-deficient, generating low-valence VOx, and a small Rs in the middle, resulting in an uneven distribution of Rs.

[0040] To address this issue, the vents at the bottom of the wafer are designed with a differentiated layout: the number of vents at the perimeter is greater than that in the center. This results in more airflow at the wafer edges, stronger convection, and a higher temperature in the edge region compared to the center. This higher temperature leads to a higher oxygen precipitation rate in the thin film at the edge region, significantly reducing the Rs distribution in the edge region and thus resolving the problem of uneven Rs distribution on the wafer.

[0041] Non-uniform gas inlets compensate for the inherent deposition non-uniformity at the wafer edge and center, thereby improving the overall uniformity of the film; the shortened gas delivery path increases the oxygen partial pressure regulation rate and narrows the target voltage fluctuation range, ultimately achieving steady-state control.

[0042] After introducing the basic principles of the present invention, various non-limiting embodiments of the present invention are described in detail below. Any number of elements in the accompanying drawings is for illustrative purposes only and not for limitation, and any naming is for distinction only and has no limiting meaning.

[0043] The principles and spirit of the present invention will be explained in detail below with reference to several representative embodiments.

[0044] Example 1: like Figure 1 The diagram illustrates a VOx thin film steady-state growth inlet device based on fast-response gas control, used to inject reactive gas into a reaction chamber 1 of a VOx thin film sputtering system. The reaction chamber 1 contains a base 2 and a heater disposed inside the base 2. The inlet device includes a reactive gas delivery channel 3, multiple inlet ports 21, and a control unit. The multiple inlet ports 21 are disposed on the platform of the base 2. One end of the reactive gas delivery channel 3 is connected to an external reactive gas source, and the other end is disposed below the base 2 and communicates with the inlet ports 21. The reactive gas delivery channel 3 delivers reactive gas to the reaction chamber 1. An electric valve is installed on the reactive gas delivery channel 3, and the control unit regulates the flow rate of the reactive gas entering the reaction chamber 1 by controlling the electric valve.

[0045] A portion of the pipeline of the reactant gas delivery channel 3 (hereinafter referred to as delivery channel 3) is integrated inside the heater, which heats the reactant gas within delivery channel 3. The pipeline integrated inside the heater is the heating channel. A pneumatic valve (this is the second pneumatic valve) is installed upstream of the heating channel in the airflow direction of delivery channel 3. Another pneumatic valve (this is the first pneumatic valve) is also installed near the external gas source end of delivery channel 3, followed by a pressure regulating valve and a flow meter arranged sequentially along the airflow direction. Both of the above pneumatic valves are fast-response valves; preferably, the fast-response valves are piezoelectric valves or voice coil valves. Delivery channel 3 is used to deliver the reactant gas—oxygen; however, in other embodiments, it can also be used to deliver the inert gas—argon.

[0046] The control unit controls the pneumatic valve, pressure regulating valve, and flow meter located on the delivery channel 3 according to the target surface voltage fluctuations, so as to regulate the flow rate of the reaction gas entering the delivery channel 3 inside the heater, and thus control the flow rate of the gas entering the reaction chamber 1. In this embodiment, the control unit is a programmable logic controller.

[0047] like Figure 2 As shown, the distribution of multiple air inlets 21 on the platform of the base 2 is as follows: the density in the edge region below the wafer is greater than that in the center region, in order to increase the temperature in the edge region of the wafer and thus compensate for the sheet resistance in the center region of the wafer. In this embodiment, the air inlets 21 are set as blind holes, and the air inlets 21 are distributed in multiple concentric rings on the platform of the base 2, with the distribution density of the air inlets 21 increasing from the inner ring to the outer ring. As a preferred embodiment, three concentric rings of air inlets 21 are provided on the platform of the base 2, the diameter of the air inlets 21 is the same, but the number of air inlets 21 in the outer ring is 1.5 times that in the center region.

[0048] Of course, in other embodiments, the number of concentric circles on the base 2 can be 2, 4, 5, or more, depending on actual needs. The distribution of the air inlets 21 from the inner to the outermost concentric circles can also be: the density of the air inlets 21 remains constant while the diameter increases; or the density of the air inlets 21 increases while the diameter increases. The number of air inlets 21 per unit area on the edge region of the base 2 platform is any value within the range of 1.5 to 3 times that of the central region, such as 2 times, 2.5 times, or 3 times.

[0049] In this embodiment, the air inlets 21, configured as blind holes, are connected to the conveying channel 3 at their bottoms via transverse connecting holes 22. Each air inlet 21 corresponds to one transverse connecting hole 22. The air inlets 21 located in different concentric rings have different depths. The base 2 has three layers of transverse connecting holes 22 inside, the number of layers of transverse connecting holes 22 being the same as the number of concentric rings of the air inlets 21, and each layer of transverse connecting holes 22 is connected to the bottom of the corresponding ring of air inlets 21 at the same depth. Each layer of transverse connecting holes 22 is arranged radially (e.g., ...). Figure 3(As shown). The gas inlets 21 at different depths, connected by lateral connecting holes 22 at different levels, form independent gas delivery pathways that isolate different annular regions from each other. This ensures that the gas flow to a specific region of the wafer is not affected by any gas regulation to other regions. Furthermore, dispersing the flow channels (i.e., the lateral connecting holes 22) at different depths avoids excessive cutting on a single plane, which helps maintain the overall structural rigidity of the base 2. Simultaneously, this arrangement also facilitates the layout of the heater's thermal field. Compared to concentrating all flow channels in one layer, which severely interferes with the local thermal field, layered flow channel arrangement reduces the adverse effects on the heater's temperature uniformity, thereby indirectly ensuring the uniformity of substrate heating and thus improving the film deposition quality.

[0050] The above-mentioned air intake device is suitable for magnetron sputtering systems for vanadium oxide thin films.

[0051] contrast Figure 4 and Figure 5 As can be seen, the direct gas supply path shortens the feedback delay. This invention eliminates the traditional gas nozzle and integrates the oxygen delivery channel inside the heater, allowing oxygen to flow directly from the back side of the wafer to the reaction zone. The oxygen control node is shortened, the control unit response time is reduced, and the residence time in the transition zone is shortened.

[0052] Traditional sputtering systems typically use long gas nozzles on the sidewalls of the reaction chamber to improve oxygen distribution uniformity within the working space. This necessitates extending the gas pipeline to the middle of the reaction chamber and connecting it to an adapter mounted outside the chamber. The reactant gas flows through the adapter into the long gas nozzle before reaching the reaction chamber. This traditional gas inlet design results in an excessively long gas delivery path, which in turn lengthens the gas control loop and exacerbates the gas control response lag. Figure 4 The schematic diagram of a traditional gas control loop shows that during the reactive sputtering process, oxygen is output from an oxygen cylinder and passes sequentially through actuators such as a first pneumatic valve, a pressure regulating valve, a flow meter, and a second pneumatic valve. It then enters the vacuum chamber through pipelines, adapters, and nozzles. Simultaneously, the target voltage (reflecting reaction states such as "target poisoning") is fed back to the programmable logic controller (i.e., the control unit). The control unit then regulates the actuators such as the first pneumatic valve to form a closed-loop gas control loop based on the target voltage feedback, thereby regulating the flow rate of the reactive gas (oxygen) and maintaining the reaction process.

[0053] This invention eliminates the long gas nozzle structure within the reaction chamber. Instead, the air inlet is located on the base platform, while the heater is situated inside the base. The gas delivery channel supplies gas to the air inlet on the base platform via the heater. Positioning the air inlet on the base platform significantly shortens the gas delivery path. The gas flows directly from the external gas source into the reaction chamber from the bottom, bypassing the adapter in the middle of the chamber and then the long gas nozzle before entering the reaction chamber. This shortened gas delivery path also shortens the gas control loop. Figure 5 The schematic diagram of the gas control loop of the present invention shows that oxygen is output from an oxygen cylinder and passes sequentially through actuators such as a first pneumatic valve, a pressure regulating valve, a flow meter, and a second pneumatic valve. Then, it is heated by a heater in the base to make the oxygen temperature suitable for the process environment inside the cavity. After heating, the oxygen enters the vacuum cavity through the air inlet and participates in the reaction sputtering process of the target material. At the same time, the target surface voltage (reflecting the reaction state such as "target poisoning") is fed back to the programmable logic controller (i.e., control unit). The control unit then adjusts the actuators such as the first pneumatic valve in real time to form a gas closed-loop control loop based on the target surface voltage feedback, so as to realize the closed-loop control of oxygen flow and ensure the stability of the reaction sputtering process.

[0054] The air intake device of this invention optimizes the gas delivery path, shortens the gas delivery path, reduces the response time required by the gas control loop, and shortens the residence time of the reactant gas in the transition zone (near the target voltage range), ultimately achieving stable control of the target voltage.

[0055] Figure 6 and 7 This diagram illustrates the process of target voltage changing dynamically from its initial state to its eventual stabilization during reactive sputtering, before and after the improvement, as oxygen is introduced and the "target poisoning" effect develops.

[0056] contrast Figure 6 and 7 It can be seen that: after the improvement, the target voltage fluctuation is narrowed, and the short path increases the oxygen partial pressure regulation rate, shortening it from 86.346s to 56.346s; thus achieving steady-state control of oxygen partial pressure.

[0057] Figure 8 The distribution map of the surface resistance of the wafer before improvement shows that the average resistance value before improvement is 426.72 KΩ and the uniformity is 4.521%. Figure 9 The image shows the distribution map of the surface resistance values ​​of the wafer in this invention. From the image, we can see that the average resistance value after the improvement is 307.72 KΩ and the uniformity is 0.82%.

[0058] contrast Figure 8 and Figure 9 As can be seen, the uniformity of the wafer surface resistance value of the present invention is better than that of the previous version.

[0059] Example 2: Its main difference from Example 1 is: In this embodiment, the reaction gas delivery channel includes a first branch and a second branch that are independent of each other. The first branch supplies gas to the air inlet in the central area, and the second branch supplies gas to the air inlets in the surrounding edge areas. The first branch and the second branch are respectively equipped with valves that can independently adjust the flow rate.

[0060] Based on the above description in this specification, those skilled in the art will also understand that terms used, such as "upper," "lower," "inner," "outer," and "depth," which indicate orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings of this specification. They are only for the purpose of facilitating the explanation of the present invention and simplifying the description, and do not imply that the device or element involved must have the specific orientation, or be constructed and operated in a specific orientation. Therefore, the above-mentioned orientation or positional relationship terms should not be understood or interpreted as a limitation on the present invention.

[0061] In addition, in the description of this specification, "multiple" means at least two, such as two, three or more, etc., unless otherwise expressly and specifically defined.

Claims

1. A VOx thin film steady-state growth inlet device based on fast-response gas control, used to inject reactive gas into a reaction chamber of a VOx thin film sputtering system, wherein the reaction chamber is provided with a base and a heater disposed inside the base, characterized in that: The air intake device includes: A reaction gas delivery channel is provided, which is connected to an external reaction gas source to deliver reaction gas to the reaction chamber. The delivery channel is located below the base. Multiple air inlets are disposed on the base platform and communicate with the conveying channel. The distribution of the multiple air inlets on the base platform is such that the density in the lower edge region of the wafer is greater than the density in the center region. The air inlet is configured as a blind hole, and its bottom is connected to the conveying channel through a transverse connecting hole; The air intake holes are distributed in multiple concentric rings, and the distribution density and / or diameter of the air intake holes increase from the inner ring to the outer ring. The depths of the air intake holes located in different concentric annular regions are different; At least a portion of the conveying channel is integrated inside the heater, and the conveying channel integrated inside the heater is a heating channel; The base has three layers of transverse connecting holes inside. The number of layers of transverse connecting holes is the same as the number of concentric rings of the air intake holes. Each layer of transverse connecting holes is connected to the bottom of the corresponding ring of air intake holes at the same depth. Each layer of transverse connecting holes is arranged radially.

2. The VOx thin film steady-state growth inlet device based on fast-response gas control as described in claim 1, characterized in that, The number of air inlets per unit area in the edge region of the base platform is 1.5-3 times that in the central region.

3. The VOx thin film steady-state growth inlet device based on fast-response gas control as described in claim 1, characterized in that, The conveying channel is equipped with a pneumatic valve located upstream of the heating channel in the airflow direction.

4. The VOx thin film steady-state growth inlet device based on fast-response gas control as described in claim 3, characterized in that, It also includes a control unit that controls a pneumatic valve located upstream of the heater based on the target voltage fluctuation, so as to regulate the flow rate of the reaction gas entering the delivery channel inside the heater.

5. The VOx thin film steady-state growth inlet device based on fast-response gas control as described in claim 1, characterized in that, The reaction gas delivery channel includes a first branch and a second branch that are independent of each other. The first branch supplies gas to the air inlet in the central region, and the second branch supplies gas to the air inlet in the edge region. The first branch and the second branch are respectively equipped with valves that can independently adjust the flow rate.

6. The VOx thin film steady-state growth inlet device based on fast-response gas control as described in any one of claims 1-5, characterized in that, The air intake device is suitable for magnetron sputtering systems for vanadium oxide thin films.

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