Vacuum coating method

Abstract

The application discloses a vacuum coating method. The vacuum coating method comprises the following steps: placing a substrate into a process cavity; inputting a heated inert protective gas into the process cavity; switching between the heated inert protective gas and a process gas until the substrate is heated to a preset temperature; and inputting the process gas into the process cavity to coat the substrate. By inputting the heated inert protective gas into the process cavity, the heated inert protective gas can flow through the process cavity in a dynamic manner to heat the substrate by heat convection. Therefore, the time for heating the substrate to the preset temperature can be effectively shortened, the production efficiency is improved, the uniformity of the heating temperature is improved, the thermal deformation of the substrate is reduced, and the coating quality is improved.

Description

Technical Field

[0001] This application relates to the field of coating technology, and in particular to vacuum coating methods. Background Technology

[0002] In industrial production, workpieces such as semiconductors or metals require surface coating processes to achieve desired surface properties. Related technologies typically involve heating the substrate to enhance its surface activity or to achieve suitable coating process conditions. Currently, resistance heaters are usually placed inside or outside the reaction chamber to heat the substrate via radiation or direct contact. However, this heating method suffers from uneven heating and the substrate's susceptibility to thermal deformation, leading to a decline in coating quality. Summary of the Invention

[0003] The embodiments of this application provide a vacuum coating method that can improve production efficiency and vacuum coating quality.

[0004] This application provides a vacuum coating method. The vacuum coating method includes placing a substrate into a process chamber; controlling the input of a heated inert protective gas into the process chamber; heating the substrate to a preset temperature; switching between the heated inert protective gas and a process gas; and controlling the input of the process gas into the process chamber to coat the substrate.

[0005] The beneficial effects of this application are as follows: Unlike existing technologies, by controlling the input of preheated inert protective gas into the process chamber, the substrate can be heated by thermal convection through the dynamic flow of the preheated inert protective gas through the process chamber. Compared with related technologies that use resistance heaters for radiant heating or direct contact heating of the substrate, heating the substrate with preheated inert protective gas can not only effectively shorten the time to heat the substrate to the preset temperature and improve production efficiency, but also improve the uniformity of heating temperature and reduce the thermal deformation of the substrate, thereby improving the coating quality. Attached Figure Description

[0006] Figure 1 This is a schematic diagram of the structure of an embodiment of the vacuum coating equipment of this application;

[0007] Figure 2 This is a schematic diagram of another embodiment of the vacuum coating equipment of this application;

[0008] Figure 3 This is a schematic flowchart of the vacuum coating method according to an embodiment of this application. Detailed Implementation

[0009] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0010] In industrial production, workpieces such as semiconductors or metals require surface coating processes on their substrates to achieve desired surface properties. Related technologies typically involve heating the substrate to enhance its surface activity or to achieve suitable coating process conditions. Currently, non-contact radiant heating methods are commonly used in vacuum coating equipment, such as heating the substrate with an electric heater placed outside the furnace chamber. Alternatively, direct contact heating methods are used, such as directly heating the substrate inside the furnace chamber using a resistance heater. However, radiant heating in the low-temperature conditions of 100–300°C in vacuum coating suffers from low radiant energy, long heating times, and slow heating of large workpieces. Contact heating offers short heating times but uneven heating, resulting in temperature gradients in the heated object and limiting its application. For example, contact heating cannot be used when both sides need to be heated, and direct contact heating can cause excessively rapid temperature rise, potentially leading to deformation of heat-stress-sensitive substrates. To address these technical problems, this application provides the following embodiments.

[0011] Combination Figure 1 and Figure 2This application provides a vacuum coating apparatus 100. The vacuum coating apparatus 100 includes a process chamber 110, a first inlet pipe 120, a second inlet pipe 130, and an exhaust pipe 150. The process chamber 110 can accommodate a substrate 200 and is used for the coating process. The substrate 200 within the process chamber 110 can react with the process gas to form a film layer on its surface. The first inlet pipe 120 is connected to the process chamber 110 and is equipped with a first inlet valve 123. The second inlet pipe 130 is connected to the process chamber 110 and is equipped with a second inlet valve 132. The first inlet pipe 120 and the second inlet pipe 130 are used to introduce gaseous materials required for the coating process, such as inert protective gas and process gas, from a gas source into the process chamber 110. The first intake valve 123 and the second intake valve 132 are used to control the opening and closing of the first intake pipe 120 and the second intake pipe 130, respectively, thereby controlling the intake timing. In the embodiments of this application, the first intake pipe 120 is used to introduce an inert protective gas, such as nitrogen or argon. The second intake pipe 130 is used to introduce the process gas required for coating, such as trimethylaluminum, titanium tetrachloride, or hafnium tetrachloride, etc., without specific limitation. The exhaust pipe 150 is connected to the process chamber 110. The exhaust pipe 150 can exhaust the gas in the process chamber 110, thereby realizing the exhaust of the gaseous material, or evacuating the process chamber and reducing the gas pressure in the process chamber 110 to make the process chamber 110 a vacuum state.

[0012] The first air inlet pipe 120 includes a first heating pipe 121 and a first airflow pipe 122. The first heating pipe 121 is provided with a first fluid heater 1211, which can heat the gas flowing through it, for example, it can heat the inert protective gas, so that the inert protective gas can heat the substrate 200 after it is introduced into the process chamber 110.

[0013] Combination Figure 3 The following is an exemplary description of a method for performing vacuum coating using the vacuum coating equipment 100 described above. The steps for performing vacuum coating based on the provided vacuum coating equipment 100 are described below.

[0014] S10: Control the first fluid heater 1211 to turn on.

[0015] The first air inlet pipe 120 is connected to the process chamber 110, and the first air inlet pipe 120 is equipped with a first air inlet valve 123. The first air inlet pipe 120 is used to introduce the inert protective gas required for the coating process from the gas source into the process chamber 110. The first air inlet pipe 120 includes a first heating pipe 121 and a first airflow pipe 122. The first heating pipe 121 is equipped with a first fluid heater 1211, which can heat the gas flowing through it, for example, it can heat the inert protective gas. Before the substrate 200 is placed into the process chamber 110, the first fluid heater 1211 can be activated to heat the inert protective gas, that is, to preheat the inert protective gas in advance, thereby preparing for the use of the preheated inert protective gas later.

[0016] In one embodiment, the second intake line 130 includes a second fluid heater 131, in which case step S10 further includes the step:

[0017] S11: While controlling the first fluid heater 1211 to turn on, control the second fluid heater 131 to turn on.

[0018] The second air inlet pipe 130 is connected to the process chamber 110 and is equipped with a second air inlet valve 132. The second air inlet pipe 130 is used to introduce the process gas required for the coating process from a gas source into the process chamber 110. The second air inlet pipe 130 includes a second airflow pipe and a second heating pipe. The second heating pipe is equipped with a second fluid heater 131, which can heat the gas flowing through it, for example, it can heat the process gas. Similarly, before placing the substrate 200 into the process chamber 110, turning on the second fluid heater 131 can preheat the process gas, thus preparing it for subsequent use.

[0019] In some embodiments, the second air inlet pipe 130 may not be equipped with a second fluid heater. Instead, the process gas is heated by heating the gas source, such as heating the gas source cylinder. Then, an insulation layer is wrapped around the outer periphery of the second air inlet pipe 130 to ensure that the process gas introduced into the process cavity 110 has a certain temperature.

[0020] In one embodiment, a heating device 160 is provided on the outer periphery of the process cavity 110. The heating device 160 may be, for example, a resistance heater or a heating rod. In this case, step S10 further includes the step:

[0021] S12: While controlling the first fluid heater 1211 to open, the heating device 160 is also controlled to open to the first preset temperature. A heating device 160 is provided on the outer periphery of the process chamber 110. The heating device 160 heats the process chamber 110 through thermal radiation, thereby heating the interior of the process chamber 110 and the substrate 200. On the other hand, the heating device 160 insulates the process chamber 110, reducing heat loss from the inert protective gas, allowing the substrate 200 to be further heated sufficiently, and ensuring suitable temperature conditions within the process chamber 110 during subsequent coating processes. Specifically, the first preset temperature is lower than the temperature at which the substrate 200 reacts with air. Since some materials of the substrate 200 may react with air under certain temperature conditions, controlling the heating device 160 to open to the first preset temperature allows the heating device 160 to preheat the process chamber 110 while preventing the substrate 200 from reacting with air, which helps ensure coating quality. Optionally, the first preset temperature is 20-110℃, which ensures that the temperature inside the process chamber is below 100℃ before the substrate is placed in (because the temperature of the heating device 160 will be partially lost after heat transfer, the temperature inside the process chamber 110 is lower than the temperature set by the heating device 160).

[0022] It should be noted that since the first fluid heater 1211, the second fluid heater 131, and the heating device 160 preheat the inert protective gas, the process gas, and the process chamber respectively before the substrate 200 is placed into the process chamber, the steps S10, S11, and S12 are used here for ease of description. However, in actual production, there is no strict order in which the first fluid heater 1211, the second fluid heater 131, and the heating device 160 are turned on, as long as they are all turned on before the substrate is placed in to preheat the aforementioned object or substance.

[0023] S20: Place the substrate 200 to be coated into the process chamber 110.

[0024] After preheating the process chamber 110 to the first preset temperature, the substrate 200 to be coated can be placed into the process chamber 110.

[0025] To ensure the coating process environment and further prevent the substrate 20 from reacting with the gas, such as air, inside the process chamber 110, and to facilitate the entry of the heated inert protective gas into the process chamber 110, step S20 further includes:

[0026] S21: Control the first exhaust valve 1512 to be closed, and open the second exhaust valve 1522.

[0027] The negative pressure pump 1521 can reduce the air pressure in the process chamber 110 to below one standard atmosphere.

[0028] The exhaust pipe 150 includes an outlet pipe 151 and an extraction pipe 152 connected to the process chamber 110. The outlet pipe 151 is equipped with a first exhaust valve 1512, and the extraction pipe 152 is equipped with a second exhaust valve 1522. The outlet pipe 151 and the extraction pipe 152 can be used to discharge different gaseous materials respectively. For example, the outlet pipe 151 discharges the inert protective gas that enters the process chamber 110 through the first inlet pipe 120. When the process chamber 110 is evacuated, the gas in the process chamber 110 is discharged through the extraction pipe 152. The gas in the process chamber 110 can be residual inert protective gas, a mixture of inert protective gas and coating process gas, or coating process gas, etc.

[0029] In some embodiments, the vacuum coating equipment 100 further includes a negative pressure pump 1521. A suction line 152 is connected to the negative pressure pump 1521, which actively evacuates the process chamber 110. This allows the suction line 152 to reduce the air pressure within the process chamber 110, creating a vacuum environment. It also provides the power for gas flow by evacuating the process chamber 110 when the intake pressure of the first intake line 120 or the second intake line 130 is insufficient.

[0030] After the substrate 200 is placed into the process chamber 110 and before it is heated, the gas pressure inside the process chamber 110 needs to be reduced. In other words, the gas, such as air, inside the process chamber 110 needs to be exhausted to provide the process conditions for subsequent vacuum coating, and to further prevent the substrate 200 from reacting with the gas, such as air, inside the process chamber 110, and to allow the heated inert protective gas to smoothly enter the process chamber 110. Since the process chamber 110 can be preheated by the heating device 160 before the substrate 200 is placed into the process chamber 110 without exhausting the gas, or can be appropriately exhausted through the exhaust pipe 151 when it is preheated to near the first preset temperature, the first exhaust valve 1512 can be controlled to be closed after the substrate 200 is placed into the process chamber 110 and before it is heated. That is, the first exhaust valve 1512 can be kept closed or closed. After the second exhaust valve 1522 is opened, the negative pressure pump 1521 can draw gas from the process chamber 110 to remove the gas inside the process chamber 110 and reduce the gas pressure inside the process chamber 110. Optionally, the gas pressure inside the process chamber 110 can be reduced to below one standard atmosphere, for example, to below 10 Pa.

[0031] S30: Controls the exhaust pipe 150 to switch to the closed state.

[0032] After the substrate 200 is placed into the process chamber 110, or after the air pressure inside the process chamber 110 is reduced to below 10 Pa, preheated inert protective gas can be introduced to heat the substrate 200. To ensure sufficient heating of the substrate 200, the air pressure inside the process chamber 110 needs to be maintained at or above one standard atmosphere. Therefore, the exhaust pipe 150 is switched to the closed state, that is, the first exhaust valve 1512 is kept closed, and the second exhaust valve 1522 is closed, meaning that both the first exhaust valve 1512 and the second exhaust valve 1522 are in the closed state. This arrangement allows the inert protective gas to gradually fill the process chamber 110 when it is subsequently introduced, thereby fully heating the substrate 200 inside the process chamber 110.

[0033] S40: Keep the second branch valve 1241 closed and open the first branch valve 1212 to control the input of heated inert protective gas through the first branch valve and the first intake valve.

[0034] The first intake pipe 120 includes a first heating pipe 121 and a first airflow pipe 122. The first airflow pipe 122 is connected in series with the first heating pipe 121, and the first heating pipe 121 is connected to the process chamber 110 through the first airflow pipe 122. The first heating pipe 121 can heat the inert protective gas flowing through it in the above manner, and the first airflow pipe 122 can introduce the heated inert protective gas into the process chamber 110. The first intake valve 123 is connected in series between the first heating pipe 121 and the process chamber 110. In other words, the first intake valve 123 can be located in the first airflow pipe 122, or connected in series between the first airflow pipe 122 and the process chamber 110, or connected in series between the first heating pipe 121 and the first airflow pipe 122; no specific limitation is made here. The first intake valve 123 is connected in series between the first heating pipe 121 and the process chamber 110, enabling the first intake valve 123 to selectively control whether the heated inert protective gas is introduced into the process chamber 110.

[0035] In some embodiments, the first intake pipe 120 further includes an airflow branch 124, which is connected in parallel with the first heating pipe 121. The airflow branch 124 and the first heating pipe 121 are then connected in series with the first airflow pipe 122. The first heating pipe 121 is equipped with a first branch valve 1212, and the airflow branch 124 is equipped with a second branch valve 1241. This configuration allows the first intake pipe 120 to introduce heated and / or unheated inert protective gas into the process chamber 110, either separately or simultaneously, to meet the needs of different operating conditions.

[0036] Preferably, the first inlet valve 123 is located in the portion of the first airflow pipe 122 near the process chamber 110, that is, in the portion away from the first heating pipe 121. Before the inert protective gas heated by the first fluid heater 1211 is introduced into the process chamber 110 through the first inlet pipe 120, the first branch valve 1212 can be opened while the second branch valve 1241 remains closed. This prevents unheated inert protective gas from entering the first airflow pipe 122 through the airflow branch 124, and allows the inert protective gas heated by the first fluid heater 1211 in the first heating pipe 121 to enter the first airflow pipe 122 in advance until it reaches the first inlet valve 123. This shortens the distance the heated inert protective gas needs to travel into the process chamber 110, reduces heat loss, ensures heating effect, and reduces heating time.

[0037] S50: Control the first air intake valve 123 to open, and input the heated inert protective gas into the process chamber 110.

[0038] By opening the first inlet valve 123, the pre-heated inert protective gas in the first inlet pipe 120 can be introduced into the process chamber 110. The pre-heated inert protective gas can gradually fill the process chamber 110 and heat the substrate 200. Since the inert protective gas can heat multiple surfaces of the substrate 200, the heating of the substrate 200 is sufficiently uniform and less affected by the shape of the substrate 200 itself. The substrate 200 is fully and uniformly heated, which can improve the coating quality.

[0039] In some embodiments, the first air inlet pipe 120 further includes a pressure reducing valve 140, which is connected in series at the end of the first heating pipe 121 away from the process chamber 110. It should be noted that the inert protective gas provided by the gas source typically has a high pressure. If it is directly introduced into the first air inlet pipe 120 or the process chamber 110, it is not conducive to heating the inert protective gas and the substrate 200, and may damage the substrate. By setting the pressure reducing valve 140, the gas pressure of the gas source can be reduced to a suitable pressure before being introduced into the first air inlet pipe 120 and the process chamber 110, thereby ensuring that the inert protective gas and the substrate 200 are heated uniformly and preventing damage to the substrate 200.

[0040] In some embodiments, the first air inlet pipe 120 further includes a pressure regulating valve 1213, which is connected in series between the first heating pipe 121 and the process chamber 110. The first fluid heater 1211 requires a certain amount of time to heat the inert protective gas. By connecting the pressure regulating valve 1213 in series, the gas pressure before and after the pressure regulating valve 1213 can be adjusted. That is, the pressure in the first fluid heater 1211 is adjusted to be higher than the pressure in the first airflow pipe 122, so that the flow rate of the inert protective gas before the pressure regulating valve 1213 is lower than the flow rate after the pressure regulating valve 1213. This arrangement increases the time the inert protective gas resides in the first fluid heater 1211, allowing the inert protective gas to be fully heated, thereby improving the heating effect on the substrate.

[0041] In some embodiments, step S50 further includes:

[0042] S51: Simultaneously turn on the heating device 160 to a second preset temperature higher than the first preset temperature.

[0043] When the first inlet valve is opened to allow the preheated inert protective gas to be introduced into the process chamber to heat the substrate 200, the temperature of the heating device 160 can be increased to a second preset temperature higher than the first preset temperature. The second preset temperature can be the temperature of the preheated inert protective gas, or 5 to 15°C higher than the temperature of the preheated inert protective gas. On the one hand, this can keep the process chamber 110 and the substrate 200 and inert protective gas inside the process chamber 110 warm, reducing heat loss. On the other hand, the preheated inert protective gas introduced can reduce the vacuum level of the process chamber 110, allowing the heat from the heating device 160 to be transferred through the preheated inert protective gas medium. Compared with heat transfer through a vacuum medium, this can increase the radiative heat transfer energy of the heating device 160, further reducing the heating time of the substrate 200 and improving heating efficiency.

[0044] S60: When the air pressure inside the process chamber 110 is greater than the air pressure outside the process chamber 110, control the exhaust pipe 150 to switch to the open state, and discharge the inert protective gas inside the process chamber 110 through the exhaust pipe 150.

[0045] Since the temperature of the heated inert protective gas decreases after entering the process chamber 110 to perform thermal convection heating on the substrate 200, a continuous flow of heated inert protective gas is required in the process chamber 110 to ensure sufficient heating of the substrate 200. This means the heated inert protective gas must continuously and dynamically flow through the process chamber 110. By controlling the exhaust pipe 150 to be switched to the open state, the inert protective gas in the process chamber 110 can be discharged, thus ensuring a continuous flow of heated inert protective gas (after being heated by the first fluid heater 1211) into the process chamber 110 to continuously heat the substrate 200 until a preset temperature is reached. The preset temperature for heating the substrate 200 can be determined based on the required temperature of the substrate 200 in the relevant coating process, for example, it can be 120–280°C, without specific limitation here. The control of the exhaust pipe 150 to be switched to the open state requires that the gas pressure inside the process chamber 110 is greater than the gas pressure outside the process chamber 110. This configuration ensures that the air pressure inside the process chamber 110 is in a positive pressure state relative to the outside. As a result, when the exhaust pipe 150 is opened, the inert protective gas can be discharged under the action of the air pressure difference, thus preventing gas outside the process chamber 110, such as air, from flowing back into the process chamber 110 through the exhaust pipe 150 and causing pollution, which would affect the coating quality and production safety.

[0046] In one embodiment, the vacuum coating equipment includes a recovery device 1511. An outlet pipe 151 is connected to the recovery device 1511. The outlet pipe 151 is used to discharge the inert protective gas introduced through the first inlet pipe 120. Since high-purity inert protective gas is typically used in vacuum coating technology, and the heating process of the inert protective gas on the substrate 200 within the process chamber 110 is a physical heat convection process and does not chemically react with the substrate, the inert protective gas remains a relatively pure gas. By connecting the recovery device 1511 to the outlet pipe 151, the inert protective gas can be recovered, thereby reducing production costs. Optionally, a negative pressure pump 1521 is connected to a tail gas treatment device, so that the gas in the process chamber 110, such as process gas, can be treated by the tail gas treatment device after the reaction, thereby preventing air pollution. In some embodiments, the recovery device 1511 may include, for example, a compressor, a membrane separator, and a recovery tank connected in sequence, thereby enabling the compression, separation, purification, and storage of the inert protective gas. In other embodiments, the recovery device 1511 may include multiple recovery units connected in series for removing or recovering different impurity components from the inert protective gas.

[0047] In one embodiment, controlling the exhaust pipe 150 to switch to the open state specifically involves keeping the second exhaust valve 1522 closed and opening the first exhaust valve 1512, thereby discharging the inert protective gas from the process chamber 110 through the outlet pipe 151 in the exhaust pipe 150. Discharging the inert protective gas through the outlet pipe 151 allows for its separate discharge, which not only meets the positive pressure requirement within the process chamber 110, ensuring sufficient and uniform heating of the substrate 200 by the hot inert gas, but also facilitates the recycling of the inert protective gas.

[0048] S70: After heating the substrate 200 to the preset temperature, control the exhaust pipe 150 to switch to the closed state again.

[0049] After the substrate 200 is heated to a preset temperature, its surface activity can be improved, and the coating process conditions can be met, allowing the coating operation to proceed. The exhaust pipe 150 is then switched to the closed state again, specifically by keeping the second exhaust valve 1522 closed and the first exhaust valve 1512 closed. This prevents gases outside the process chamber 110, such as air, from flowing back into the process chamber 110 through the exhaust pipe 151, and also prepares for the switching between the exhaust pipe 151 and the extraction pipe 152.

[0050] S80: Control the first intake valve 123 to switch the intake.

[0051] After the exhaust pipe 150 is switched back to the closed state, the first intake valve 123 can be controlled to switch the intake, thereby limiting the inflow of the heated inert protective gas and preparing for the introduction of process gas for coating. Specifically, switching the intake of the first intake valve 123 involves adjusting it to reduce the flow rate of the heated inert protective gas to a preset flow rate. Specifically, the preset flow rate can be 0; in other words, controlling the intake of the first intake valve 123 to switch the intake can mean completely closing the first intake valve 123, completely preventing the inert protective gas from entering the process chamber 110. This reduces the impact of the inert protective gas on the reaction process during coating. In other embodiments, the preset flow rate can be the same as the flow rate of the process gas introduced in subsequent steps; in other words, controlling the intake of the first intake valve 123 to switch the intake can mean first closing the first intake valve 123 slightly, and then closing it while introducing the process gas, or closing the first intake valve 123 before introducing the process gas. With such control, the temperature and gas flow rate within the process chamber 110 can remain substantially consistent before and after the introduction of the process gas, thereby reducing fluctuations or abrupt changes in the process environment and temperature within the process chamber 110, which is beneficial for further improving the coating quality. In some embodiments, step S80 further includes:

[0052] S81: At the same time, keep the second branch valve 1241 closed, and adjust the first branch valve 1212 accordingly to adapt to the state change of the first intake valve 123.

[0053] Specifically, when the first intake valve 123 is completely closed, the first branch valve 1212 is closed; or, when the first intake valve 123 is closed slightly, the first branch valve 1212 is also closed slightly first, and then the first intake valve 123 and the first branch valve 1212 are closed at the same time as the process gas is introduced; or when the first intake valve 123 is closed before the process gas is introduced, the first branch valve 1212 is also closed accordingly.

[0054] S90: Control the exhaust pipe 150 to switch to the open state again, and reduce the air pressure in the process chamber 110 to the preset air pressure.

[0055] Since coating is usually performed under vacuum conditions, the process chamber 110 needs to be evacuated before introducing the process gas to provide the necessary pressure conditions, such as a vacuum environment, for coating. Simultaneously, this also allows the inert protective gas within the process chamber 110 to be expelled, reducing the impact of residual inert protective gas on the coating process. Optionally, the preset gas pressure can be, for example, 10-20 torr, meaning that reducing the gas pressure within the process chamber 110 to the preset pressure specifically refers to achieving a vacuum level of 10-20 torr within the process chamber 110.

[0056] The exhaust pipe 150 is switched to the open state again. Specifically, the first exhaust valve 1512 is kept closed, and the second exhaust valve 1522 is opened. The negative pressure pump 1521 discharges the gas in the process chamber 110, such as a mixture of inert protective gas and process gas, or process gas, or reaction byproducts, through the suction pipe 152 in the exhaust pipe 150, thereby reducing the gas pressure in the process chamber 110 to the preset gas pressure.

[0057] S100: Control the second air inlet valve 132 to open, realize the switching between the heated inert protective gas and the process gas, and input the process gas into the process chamber 110 to coat the substrate 200.

[0058] Based on the above description, the process gas has a certain temperature before being introduced into the process chamber 110, thereby avoiding temperature fluctuations or changes in the process environment caused by the introduction of the process gas, which could affect the coating quality. In other words, heating the process gas through the second heating pipe or by heating the gas source cylinder can ensure the consistency of the process temperature within the process chamber 110, thus helping to improve the coating quality.

[0059] The second air intake pipe 130 includes a second airflow pipe and a second heating pipe, which are connected in series. The second heating pipe is equipped with a second fluid heater 131, which heats the process gas inside the second heating pipe. The second airflow pipe then introduces the heated process gas into the process chamber 110. A second air intake valve 132 is connected in series between the second heating pipe and the process chamber 110, allowing the second air intake valve 132 to selectively control whether the heated process gas enters the process chamber 110. The second air intake pipe 130 introduces the process gas into the process chamber 110 to coat the substrate 200. Furthermore, since the exhaust pipe 152 is in the open state, after the process gas enters the process chamber 110 to coat the substrate 200, it can be drawn out of the process chamber 110 by the negative pressure pump 1521, so that the process gas in the second intake pipe 130 can be continuously introduced into the process chamber 110 and coated on the substrate 200 under vacuum conditions.

[0060] In the aforementioned step of controlling the first intake valve 123 to switch intake, if the first intake valve 123 is closed to the point that the flow rate of the heated inert protective gas is the same as the flow rate of the process gas introduced through the second intake pipe 130, then step S100 further includes:

[0061] S101: Simultaneously close the first air inlet valve 123 to achieve a stable switch between the heated inert protective gas and the process gas, that is, to achieve a smooth switch between substrate heating and substrate coating.

[0062] In some embodiments, step S100 further includes:

[0063] S102: Simultaneously keep the second branch valve 1241 closed and close the first branch valve 1212, so that the first branch valve 1212 adapts to the state change of the second branch valve 1241.

[0064] S110: When the coating is finished, keep the first branch valve 1212 closed and open the second branch valve 1241.

[0065] In some embodiments, by setting and controlling the branches, the first air inlet pipe 120 can separately or simultaneously introduce heated and unheated inert protective gas into the process chamber 110 to meet the needs of different operating conditions. Specifically, when introducing them separately, as mentioned above, by opening the first branch valve 1212 and closing the second branch valve 1241, the inert protective gas can be heated by the first heating pipe 121 and then enter the process chamber 110 through the first airflow pipe 122. The heated inert protective gas can heat the substrate 200 to be coated.

[0066] After coating the substrate 200, when the coating is finished, by keeping the first branch valve 1212 closed and the second branch valve 1241 open, the unheated inert protective gas can enter the process chamber 110 through the airflow branch 124 and then through the first airflow pipe 122. The unheated inert protective gas can not only cool the coated substrate 200, but also break the vacuum process environment of the coating at the same time. Compared with the existing vacuum coating technology, which requires separate cooling and vacuum breaking operations after coating, the above method can shorten the process time and save energy.

[0067] Therefore, by connecting the first heating pipe 121 and the airflow branch 124 in parallel, the first airflow pipe 122 can selectively heat or cool the substrate 200 through valve control, and can also perform vacuum breaking operations. After coating the substrate 200, the vacuum environment needs to be broken before the coated substrate 200 can be removed. By closing the first branch valve 1212 in the first air inlet pipe 120 and opening the second branch valve 1241, the inert protective gas in the first air inlet pipe 120 no longer needs to be heated by the first fluid heater 1211. That is, the gas entering the process chamber 110 through the first air inlet pipe 120 is unheated inert protective gas, which can be used to cool the substrate 200.

[0068] S120: Control the second intake valve 132 to close and control the first intake valve 123 to open again, thereby switching between process gas and unheated inert protective gas, so as to input unheated inert protective gas into the process chamber 110 through the second branch valve 1241 and the first intake valve 123.

[0069] This allows unheated inert protective gas to be introduced into the process chamber 110 through the first inlet pipe 120 for cooling and purging. Closing the second inlet valve 132 prevents process gas from entering the process chamber 110. Opening the first inlet valve 123 allows unheated inert protective gas from the first inlet pipe 120 to enter the process chamber 110. The inert protective gas cools the coated substrate 200 and, upon entering the process chamber 110, is first discharged through the extraction pipe 152. Thus, when the inert protective gas is introduced, any remaining process gas in the process chamber 110 is purged and carried away by the process gas, which is then drawn out through the extraction pipe 152 by the negative pressure pump 1521, preventing the inert protective gas mixed with process gas from being discharged through the outlet pipe 151. When the inert protective gas has been purged for a certain period of time and the process gas has been completely discharged, the second exhaust valve 1522 can be closed. When the gas pressure inside the process chamber 110 is greater than the gas pressure outside the process chamber 110, the first exhaust valve 1512 can be opened to prevent backflow of external gas into the process chamber 110. This allows unheated inert protective gas to continuously and dynamically flow through the reaction chamber 110, thereby fully and uniformly cooling the substrate 200. The inert protective gas can also be discharged through the exhaust pipe 151 for recycling. When the substrate 200 is cooled to an ergonomically permissible touch temperature, such as below 60°C, all valves can be closed, the process chamber 110 can be opened, and the coated substrate 200 can be removed, completing the coating process.

[0070] This application achieves heating of the substrate 200 via thermal convection by controlling the input of preheated inert protective gas into the process chamber and switching between the preheated inert protective gas and process gas. The substrate is then coated using process gas. Compared to related technologies that use resistance heaters for radiant heating or direct contact heating of the substrate 200, heating the substrate 200 with preheated inert protective gas effectively shortens the time required to heat the substrate 200 to the preset temperature, improving production efficiency. Furthermore, it enhances the uniformity of heating temperature and reduces thermal deformation of the substrate 200, thereby improving coating quality.

[0071] Furthermore, compared to the existing method of heating the substrate 200 solely through a resistance heater located outside the process chamber 110, where heat is conducted via radiation and the vacuum medium within the process chamber 110, this application can simultaneously combine a heating device 160 located outside the process chamber 110 to heat the substrate 200. Moreover, when the heating device 160 radiates heat the substrate 200, it can conduct heat through the gas medium within the process chamber 110, such as air, to heat the reaction chamber, or through the conduction of a pre-heated inert protective gas medium to heat the substrate. This can effectively improve the energy of heat transfer and the speed at which a uniform temperature field is achieved, thereby further shortening the time required to heat the substrate 200 to the preset temperature and improving production efficiency.

[0072] Calculations show that, compared with existing heating methods, this application can shorten the heating time of the substrate by 60%, and it can also be applied to heating some substrates that cannot be exposed to air 200, thus having a wider range of applications.

[0073] The above are merely embodiments of this application and do not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

1. A vacuum coating method, characterized in that, include: The first fluid heater is controlled to heat the inert protective gas, and the heating device is controlled to turn on to heat the process chamber at a first preset temperature, which is lower than the temperature at which the substrate reacts with air. Place the substrate into the process chamber; Control the exhaust pipe to switch to the closed state; The preheated inert protective gas is controlled to be input into the process chamber, and the heating device is turned on to a second preset temperature higher than the first preset temperature. Once the air pressure inside the process chamber is greater than the air pressure outside the process chamber, the exhaust pipe is switched to the open state. The process involves heating the substrate to a preset temperature, switching between the heated inert protective gas and the process gas, and controlling the input of the process gas into the process chamber to coat the substrate; including: The exhaust pipe is switched to the closed state again; Control the first intake valve to switch the intake, and adjust the first intake valve to reduce the flow rate of the heated inert protective gas to the preset flow rate; The exhaust pipe is switched to the open state again to reduce the air pressure in the process chamber to the preset air pressure. The second air inlet valve is opened and the first air inlet valve is closed, and the process gas is introduced into the process chamber to coat the substrate. The process gas is introduced at the preset flow rate.

2. The vacuum coating method according to claim 1, characterized in that, The method further includes: At the end of the coating process, the process gas is switched between the process gas and the unheated inert protective gas, and the unheated inert protective gas is controlled to be input into the process chamber. Once the substrate has been cooled to an ergonomically permissible touch temperature, the coated substrate is removed.

3. The vacuum coating method according to claim 2, characterized in that: Before controlling the opening of the first intake valve, the method further includes: Keep the second branch valve closed and open the first branch valve to control the input of the heated inert protective gas through the first branch valve and the first intake valve.

4. The vacuum coating method according to claim 3, characterized in that: Once the coating process is complete, keep the first branch valve closed and open the second branch valve; The second intake valve is closed, and the first intake valve is reopened to control the input of the unheated inert protective gas into the process chamber through the second branch valve and the first intake valve.

5. The vacuum coating method according to claim 2, characterized in that: The exhaust system includes an outlet pipe and an extraction pipe communicating with the process chamber; the outlet pipe is equipped with a first exhaust valve, and the extraction pipe is equipped with a second exhaust valve. Controlling the exhaust pipe to switch to the closed state specifically involves keeping the first exhaust valve closed and closing the second exhaust valve; Controlling the exhaust pipe to switch to the open state specifically involves keeping the second exhaust valve closed and opening the first exhaust valve; The exhaust pipe is switched to the closed state again, specifically by keeping the second exhaust valve closed and closing the first exhaust valve; The exhaust pipe is switched to the open state again, specifically by keeping the first exhaust valve closed and opening the second exhaust valve.

6. The vacuum coating method according to claim 1, characterized in that: The temperature at which the first fluid heater heats the inert protective gas is 100-300℃.

7. The vacuum coating method according to claim 2, characterized in that: Reducing the gas pressure in the process chamber to a preset pressure specifically means making the vacuum level in the process chamber 10-20 torr.

8. The vacuum coating method according to claim 2, characterized in that: Controlling the first intake valve to switch intake includes: Adjust the first intake valve to reduce the flow rate of the heated inert protective gas to a preset flow rate.

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