Wafer drying method and wafer drying equipment
By using a mixed gas and a vacuum pump to adjust the air pressure in the wafer drying equipment, combined with the Marangori effect and gas flow circulation, the problems of long and poor wafer drying time are solved, and a fast and efficient drying effect is achieved.
Patent Information
- Application Number
- CN202510690862.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-05-27
- Publication Date
- 2025-08-08
AI Technical Summary
The existing wafer drying method has a long drying time and poor drying effect. There are blind spots in drying, and it is impossible to effectively remove residual liquid impurities on the wafer surface.
The injection of mixed gases including hot inert gas and hot surfactant is adopted, combined with a vacuum pump to adjust the air pressure and gas flow, peel off the liquid membrane through the Marangori effect, and circulate drying by adjusting the gas flow and pressure, and finally, with a large flow of hot inert gas to improve the drying effect.
It significantly shortens the wafer drying time, reduces the drying blind spots, improves the drying effect and wafer cleanliness.
Smart Images
Figure CN120444862A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the technical field of wafer post-processing, and in particular to a wafer drying method and wafer drying equipment. Background Art
[0002] Wafer manufacturing is a critical link in the development of the integrated circuit industry. Contaminants are a major factor in degrading wafer surface quality and even causing defects. Cleaning technology is required to remove contaminants from the wafer surface to achieve an ultra-clean surface.
[0003] After cleaning, a lot of water or cleaning fluid residue remains on the wafer surface. Because these residues contain impurities, if left to evaporate and dry, these impurities will reattach to the wafer surface, causing contamination. Therefore, wafers must be dried to remove these residual liquids.
[0004] Wafer drying equipment typically immerses the wafers in water in a drying tank, gradually exposing them to form a liquid film. Drying gas is then sprayed onto the wafer surface, creating a Marangoni effect to remove the film and dry the wafers. Existing wafer drying methods take a long time to dry, have poor drying results, and have blind spots. Summary of the Invention
[0005] Based on this, a wafer drying method and a wafer drying device are provided to improve the drying effect of the wafer and shorten the wafer drying time.
[0006] In the first aspect, a wafer drying method is provided, comprising:
[0007] In a drying chamber, after a liquid film is formed on the surface of a wafer to be dried, a mixed gas is introduced into the drying chamber and sprayed toward the wafer surface to peel off the liquid film; the mixed gas includes a hot inert gas and a hot surfactant;
[0008] stopping the introduction of the hot surfactant into the drying chamber;
[0009] Turning on a vacuum pump connected to the drying chamber and adjusting the flow rate of the hot inert gas to first set the pressure inside the drying chamber to a first pressure and maintain it for a first time, then set the pressure inside the drying chamber to a second pressure and maintain it for a second time, repeating this process N times; the first pressure being a vacuum pressure, and the second pressure being higher than the first pressure;
[0010] The flow rate of the hot inert gas is increased and maintained for a third period of time, and then the vacuum pump is turned off.
[0011] In some embodiments, after a liquid film is formed on the surface of a wafer to be dried in a drying chamber, a mixed gas is introduced into the drying chamber and sprayed toward the wafer surface to remove the liquid film, specifically comprising:
[0012] placing the wafer to be dried in the drying tank of the drying chamber;
[0013] Filling water into the drying tank, and after the liquid level reaches a preset level that submerges the wafers, continuing to fill water for a fourth period of time and maintaining the liquid level at the preset level;
[0014] The wafer is slowly pulled up at a preset speed to separate it from the liquid surface of the drying tank, and the mixed gas is sprayed toward the wafer in the drying chamber.
[0015] In some embodiments, stopping the introduction of the surfactant into the drying chamber specifically includes:
[0016] When the wafer is completely out of the liquid surface, the introduction of the surfactant into the drying chamber is stopped.
[0017] In some embodiments, the preset speed is 1 cm / min to 2 cm / min.
[0018] In some embodiments, the step of filling water into the drying tank, and after the liquid level reaches a preset level for submerging the wafers, continuing to fill water for a fourth period of time and maintaining the liquid level at the preset level further comprises:
[0019] Inert gas is introduced into the drying chamber simultaneously.
[0020] In some embodiments, before the step of starting the vacuum pump in communication with the drying chamber, the method includes:
[0021] The flow rate of the hot inert gas is increased to drain the water in the drying tank.
[0022] In some embodiments, adjusting the flow rate of the hot inert gas to first set the internal pressure of the drying chamber to a first pressure and maintain it for a first time, and then setting the internal pressure of the drying chamber to a second pressure and maintaining it for a second time, includes:
[0023] reducing the flow rate of the hot inert gas so that the pressure inside the drying chamber reaches the first pressure and maintains it for a first time period;
[0024] The flow rate of the hot inert gas is increased to make the internal pressure of the drying chamber the second pressure and maintain it for a second time period.
[0025] In some embodiments, after increasing the flow rate of the hot inert gas and maintaining it for a third period of time, and then shutting down the vacuum pump, the process further includes:
[0026] When the internal pressure of the drying chamber reaches atmospheric pressure, the introduction of the hot inert gas is stopped.
[0027] In some embodiments, after a liquid film is formed on the surface of the wafer to be dried in the drying chamber, before the step of introducing a mixed gas into the drying chamber and spraying it toward the wafer surface to strip the liquid film, the method further includes:
[0028] Introduce inert gas into the drying chamber and turn on the exhaust device.
[0029] In a second aspect, the present application provides a wafer drying device, comprising a drying chamber, a support assembly, a vacuum pump, a first flow path, a second flow path, a first valve provided in the first flow path, a second valve provided in the second flow path, an injection assembly, and a controller;
[0030] The first flow path is used to circulate inert gas, and the second flow path is used to circulate vaporized surfactant;
[0031] The spray assembly and the support assembly are located in the drying chamber, the support assembly is used to support the wafer, the spray assembly is connected to the first flow path and the second flow path, and is used to spray a mixed gas formed by the inert gas and the surfactant onto the wafer on the support assembly; the vacuum pump is connected to the drying chamber and the atmosphere;
[0032] The controller controls the connection between the first valve, the second valve and the vacuum pump, and can execute any of the wafer drying methods described above.
[0033] The above-described wafer drying method and equipment first utilize the Marangoni effect to strip the liquid film from the wafer surface, achieving a preliminary drying effect. The pressure within the drying chamber is then adjusted by repeatedly decreasing and increasing the flow rate of the hot inert gas, accelerating wafer drying and minimizing blind spots. Finally, a high-flow rate of hot inert gas is used to forcefully purge the wafer, enhancing the drying effect. This significantly shortens wafer drying time and minimizes blind spots, improving drying efficiency. BRIEF DESCRIPTION OF THE DRAWINGS
[0034] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiment below. The accompanying drawings are for illustration purposes only and are not to be considered as limiting the present application. The same reference numerals are used throughout the drawings to represent the same components. In the drawings:
[0035] Figure 1 Schematic diagram of the composition of wafer drying equipment in some embodiments.
[0036] Figure 2Schematic diagram of the partial structure of wafer drying equipment in some embodiments.
[0037] Figure 3 for Figure 2 Another orientation view of the wafer drying equipment is shown.
[0038] Figure 4 Schematic diagram of the process of wafer drying methods according to some embodiments.
[0039] Figure 5 Schematic diagram of the process flow of wafer drying methods according to other embodiments.
[0040] The accompanying drawings in the specific implementation manner are as follows:
[0041] 100, wafer drying equipment; 200, wafer; 10, drying chamber; 20, support assembly; 21, supporting member; 22, lifting mechanism; 30, vacuum pump; 40, first flow path; 50, second flow path; f1, first valve;
[0042] f2, second valve; 60, spray assembly; 70, drying tank; 71, water injection pipe; 72, exhaust pipe; 80, exhaust device. DETAILED DESCRIPTION
[0043] To make the above-mentioned objects, features, and advantages of the present application more clearly understood, the specific embodiments of the present application are described in detail below with reference to the accompanying drawings. The following description sets forth many specific details to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways than those described herein, and those skilled in the art can make similar improvements without violating the scope of the present application. Therefore, the present application is not limited to the specific embodiments disclosed below.
[0044] In the description of the present application, it should be understood that, if any, terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", and "circumferential" indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.
[0045] Furthermore, if used, the terms "first" and "second," if present, are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features being referred to. Thus, a feature specified as "first" or "second" may explicitly or implicitly include at least one such feature. Throughout the description of this application, "plurality" means at least two, for example, two, three, etc., unless otherwise specifically defined.
[0046] In this application, unless otherwise expressly specified or limited, terms such as "mounted," "connected," "connected," and "fixed" should be interpreted broadly. For example, they can refer to fixed connection, detachable connection, or integration; mechanical connection or electrical connection; direct connection or indirect connection through an intermediate medium; internal communication between two components or interaction between two components, unless otherwise expressly limited. Those skilled in the art will understand the specific meanings of the above terms in this application based on specific circumstances.
[0047] In this application, unless otherwise expressly specified or limited, when a first feature is "above" or "below" a second feature, it can mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Furthermore, when a first feature is "above," "above," or "above" a second feature, it can mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is "below," "below," or "below" a second feature, it can mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.
[0048] It should be noted that, if present, when an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be an intermediate element. When an element is referred to as being "connected to" another element, it may be directly connected to the other element or there may be an intermediate element. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only embodiments.
[0049] In order to improve the drying effect of wafers and shorten the wafer drying time, the embodiments of the present application provide a wafer drying method and a wafer drying device.
[0050] In order to facilitate understanding of the wafer drying method proposed in this application, the wafer drying device proposed in the embodiment of this application is first introduced. Figure 1 、 Figure 2 and Figure 3The wafer drying equipment 100 proposed in an embodiment of the present application includes a drying chamber 10, a support assembly 20, a vacuum pump 30, a first flow path 40, a second flow path 50, a first valve f1 provided in the first flow path 40, a second valve f2 provided in the second flow path 50, an injection assembly 60 and a controller.
[0051] The drying chamber 10 is used to provide a clean, dry environment. A support assembly 20 is disposed within the drying chamber 10 and is used to support wafers 200. The support assembly 20 includes a support member 21 for holding the wafers 200. The support member 21 may include a slot for holding the wafers 200. Furthermore, the support assembly 20 may include a lifting mechanism 22 connected to the support member 21 to drive the lifting mechanism.
[0052] The first flow path 40 is used to circulate inert gas, and the second flow path 50 is used to circulate vaporized surfactant. The injection assembly 60 is arranged in the drying chamber 10, which is connected to the first flow path 40 and the second flow path 50, and is used to spray a mixed gas formed by a mixture of inert gas and surfactant onto the wafer 200 on the support assembly 20. Nitrogen can be used as the inert gas, which is economical. Of course, other inert gases such as argon, helium, etc. can also be used. The surfactant can be isopropyl alcohol (IPA), or other substances such as diacetone alcohol, propylene glycol methyl ether, ethanol, ethylene glycol monoethyl ether, and / or acetone.
[0053] Optionally, a heater is provided on the first flow path 40 to heat the inert gas. Optionally, the wafer drying apparatus 100 further includes an atomizing barrel, in which the liquid surfactant is atomized and then transported to the spray assembly 60 via the second flow path 50. A heater can be provided on the second flow path 50 to further heat the atomized surfactant.
[0054] The injection assembly 60 can be positioned directly above, diagonally above, or to the side of the support assembly 20. The specific structure of the injection assembly 60 can be conventional, for example, including an injection plate with multiple injection holes. It should be noted that the first flow path 40 and the second flow path 50 can be connected to the injection assembly 60 via a mixing flow path, so that the inert gas and the vaporized surfactant are mixed and delivered into the drying chamber 10.
[0055] The vacuum pump 30 is connected to the drying chamber 10 and the atmosphere. Specifically, the vacuum pump 30 can be located outside the drying chamber 10 and connected to the drying chamber 10 through a pipeline.
[0056] The controller controls the connection between the first valve f1, the second valve f2, and the vacuum pump 30. When the controller activates the vacuum pump 30, it removes gas from the drying chamber 10, reducing its pressure. Alternatively, the injection assembly 60 may be positioned at the top of the drying chamber 10, with the vacuum pump 30 connected to the bottom of the drying chamber 10. The controller can control the opening of the first valve f1 and the second valve f2 to adjust the flow of the inert gas and surfactant.
[0057] In addition, the wafer drying apparatus 100 may further include an exhaust device 80 for exhausting the gas in the drying chamber 10. The exhaust device 80 generally includes an exhaust fan.
[0058] The following describes the wafer drying method proposed in the embodiments of the present application.
[0059] Please refer to Figure 4 The wafer drying method proposed in the embodiment of the present application includes:
[0060] S1. In the drying chamber 10, after a liquid film is formed on the surface of the wafer 200 to be dried, a mixed gas is introduced into the drying chamber 10 and sprayed toward the surface of the wafer 200 to remove the liquid film. The mixed gas includes a hot inert gas and a hot surfactant.
[0061] In practice, an external robot places the wafer 200 to be dried onto the support assembly 20 within the drying chamber 10. Once the wafer 200 is placed on the support assembly 20, a liquid film forms on the surface of the wafer 200 to be dried. This liquid film can be, but is not limited to, a water film, as long as the gas mixture and the liquid film can produce a Marangoni effect on the surface of the wafer 200.
[0062] There are many ways to form a liquid film on the wafer 200. In some embodiments, the wafer drying equipment 100 includes a drying tank 70 and a water injection flow path. The drying tank 70 is arranged in the drying chamber 10, and the water injection flow path is connected to the drying tank 70 for injecting water into the drying tank 70. One operating method is that the lifting mechanism 22 drives the supporting member 21 to descend, so that the wafer 200 on the supporting member 21 enters the drying tank 70 and is immersed in water. Then, the lifting mechanism 22 drives the supporting member 21 to rise, so that the wafer 200 is separated from the liquid surface, and the surface of the wafer 200 is gradually exposed and attached with a liquid film. Another operating method is that the lifting mechanism 22 drives the supporting member 21 to descend until the wafer 200 is located in the drying tank 70 and is immersed in water, and then slowly drains the water in the drying tank 70 to lower its liquid level until the liquid level is lower than the wafer 200 (such as draining all the water), and the surface of the wafer 200 is gradually exposed and attached with a liquid film. In other embodiments, a shower assembly may be disposed in the drying chamber 10 to spray water onto the wafer 200 at the support assembly 20 so that a liquid film adheres to the surface of the wafer 200 .
[0063] In step S1, the controller opens the first valve f1 and the second valve f2, allowing the hot inert gas and the hot surfactant to mix and flow to the injection assembly 60, and then be sprayed toward the wafer 200 through the injection assembly 60. Specifically, the inert gas can be nitrogen and the surfactant can be IPA (isopropyl alcohol). The mixed gas is sprayed at the meniscus where the wafer 200, the liquid film, and the air intersect. The liquid film is peeled off by the Marangoni effect along the meniscus, achieving preliminary drying of the wafer 200.
[0064] It is understandable that in step S1 , when the hot inert gas and hot surfactant are introduced, the exhaust device 80 is turned on simultaneously to make the gas in the drying chamber 10 flow, take away moisture and particles in the air, and prevent impurities from re-attaching to the surface of the wafer 200 .
[0065] S2. Stop introducing the hot surfactant into the drying chamber 10.
[0066] Specifically, the controller closes the second valve f2 to stop the introduction of the hot surfactant. At this time, the introduction of the hot inert gas is continued.
[0067] S3. Turn on the vacuum pump 30 connected to the drying chamber 10 and adjust the flow rate of the hot inert gas. First, the air pressure inside the drying chamber 10 is set to a first pressure and maintained for a first time. Then, the air pressure inside the drying chamber 10 is set to a second pressure and maintained for a second time. This cycle is performed N times in sequence. The first pressure is the vacuum pressure, and the second pressure is higher than the first pressure.
[0068] When the vacuum pump 30 is turned on, the hot inert gas is kept flowing in, and the flow rate of the hot inert gas is adjusted to change the air pressure in the drying chamber 10. Specifically, after the vacuum pump 30 is turned on, a small flow rate of hot inert gas is first introduced so that the air pressure in the drying chamber 10 is maintained at a first air pressure (which is the vacuum air pressure, and the drying chamber 10 is in a low vacuum state) and maintained for a first time period. During this process, the inert gas forms a positive pressure area in the drying chamber 10, and the vacuum pump 30 forms a negative pressure area in the drying chamber 10. The airflow in the flow field between the positive and negative pressure areas flows rapidly through the wafer 200, accelerating the peeling of the residual liquid film on the wafer 200 and accelerating the drying of the wafer 200.
[0069] After the first duration, the flow rate of the hot inert gas is increased, and the hot inert gas is introduced at a large flow rate to maintain the air pressure in the drying chamber 10 at a second pressure (higher than the first pressure). The second pressure can be atmospheric pressure, positive pressure, or vacuum negative pressure, as long as it is higher than the first pressure. By maintaining a large flow rate of hot inert gas for the second duration, the hot inert gas can fully contact the wafer 200, the drying range of the wafer 200 is larger, the blind area of the wafer 200 is reduced, and the drying effect of the wafer 200 is improved.
[0070] The hot inert gas is introduced at a "small flow rate" and a "large flow rate" for a first time period and a second time period respectively as a cycle unit, and the cycle is repeated N times.
[0071] It should be noted that in step S3, "small flow rate" and "large flow rate" are relative concepts and do not impose specific restrictions on the flow rate. For example, the "small flow rate" can be equivalent to the flow rate of the hot inert gas in step S1, or it can be obtained by reducing the flow rate of the hot inert gas in step S1.
[0072] The first air pressure and the second air pressure may both be point values or range values.
[0073] When the power of the vacuum pump 30 remains unchanged, the controller can ensure that the drying chamber 10 is at the required air pressure by controlling the flow rate of the inert gas. For example, a flow meter is set on the first flow path 40, and the controller dynamically adjusts the opening of the first valve f1 according to the detection result of the flow meter, so that when the result detected by the flow meter is within the set flow range, the default air pressure in the drying chamber 10 meets the demand. The controller can also directly adjust the flow rate of the inert gas based on the air pressure. For example, an air pressure detection component is set in the drying chamber 10, and the controller is connected to the air pressure detection component in communication, and adjusts the opening of the first valve f1 according to the result of the air pressure detection component to adjust the flow rate of the inert gas.
[0074] S4. Increase the flow rate of the hot inert gas and keep it for a third period of time, then turn off the vacuum pump 30.
[0075] The flow rate of the hot inert gas in step S4 is higher than that in step S3. At this point, the hot inert gas is used to vigorously purge the wafers 200, and the vacuum pump 30 is used to accelerate the gas flow within the drying chamber 10, further enhancing the drying of the wafers 200. After the third period of time, the drying process is essentially complete, and the vacuum pump 30 is turned off.
[0076] The wafer drying method proposed in the embodiments of this application first uses the Marangoni effect to strip the liquid film from the surface of wafer 200, achieving a preliminary drying effect. The pressure within drying chamber 10 is then adjusted by repeatedly decreasing and increasing the flow rate of the hot inert gas, accelerating the drying of wafer 200 and reducing the drying blind spot. Finally, a high flow rate of hot inert gas is forcefully purged through wafer 200 to enhance the drying effect. This method not only significantly shortens the drying time of wafer 200 but also reduces the drying blind spot, improving the drying effect.
[0077] Understandably, N is greater than 1. Specifically, in the embodiment, N is equal to 2 or 3. That is, the hot inert gas is introduced at a "low flow rate" and then at a "high flow rate" for the first and second durations, respectively, for 2-3 cycles. This achieves a better drying effect in a shorter drying time.
[0078] Specifically in the embodiment, the third time length, the first time length, and the second time length decrease in sequence. During the first time length, the adsorption effect of the vacuum pump 30 can accelerate the extraction of liquid from the surface of the wafer 200. During the second time length, the hot inert gas can fully contact the wafer 200, reducing the drying blind area. During the third time length, the hot inert gas vigorously blows the wafer 200, further enhancing the drying effect of the wafer 200. The longer the third time length is, the easier it is to ensure the drying effect of the wafer 200. Since the first and second time lengths are cycled many times, the time is relatively short, which is conducive to shortening the entire drying cycle.
[0079] Specifically, the third duration may be 5 minutes to 10 minutes, the first duration may be 45 seconds to 2 minutes, and the second duration may be 15 seconds to 1 minute.
[0080] Specifically, the temperature of the hot inert gas in the embodiment of the present application is between 40°C and 50°C.
[0081] In some embodiments, reference Figure 5 In the drying chamber 10 , after a liquid film is formed on the surface of the wafer 200 to be dried, a mixed gas is introduced into the drying chamber 10 and sprayed toward the surface of the wafer 200 to remove the liquid film. Step S1 specifically includes:
[0082] S11, placing the wafer 200 to be dried in the drying tank 70 of the drying chamber 10;
[0083] Specifically, the lifting mechanism 22 can be used to drive the supporting member 21 to descend into the drying tank 70 , so that the wafer 200 is placed in the drying tank 70 . At this time, the supporting member 21 keeps supporting the wafer 200 .
[0084] S12, pouring water into the drying tank 70, and after the liquid level reaches a preset level that submerges the wafers 200, continuing to pour water for a fourth time period and maintaining the liquid level at the preset level;
[0085] Specifically, a water injection pipe 71 is provided at the bottom of the drying tank 70, and the water injection pipe 71 forms the above-mentioned water injection flow path. Water is injected into the drying tank 70 from bottom to top through the water injection pipe 71. When the liquid level of the water reaches the preset liquid level, the water submerges the wafer 200. The water injection is continued for a fourth time period, and the liquid level is maintained at the preset liquid level. At this time, the water injection and drainage of the drying tank 70 are carried out simultaneously, which can maintain the flow of water in the drying tank 70, prevent particles in the liquid from being adsorbed on the wafer 200, and improve the cleanliness of the wafer 200. It is worth mentioning that the "water" here can be deionized water, pure water, etc.
[0086] To maintain the water level at a preset level and ensure water flow, one approach is to set the preset level as the maximum water level in the drying tank 70. This means that once the drying tank 70 is filled (reaching the preset level), water is continued to be poured, causing overflow, thereby ensuring water flow within the drying tank 70. In some specific examples, a water receiving trough is provided within the drying chamber 10, and the drying tank 70 is located within the water receiving trough. Overflowing water flows into the receiving trough for collection. Furthermore, the water receiving trough has a drain pipe, so that in the event of overflow, water can be simultaneously drained out through the drain pipe.
[0087] Another way is that the drying tank 70 has an emptying pipe 72. When the water reaches a preset liquid level, the emptying pipe 72 is opened, and the water injection amount is equal to the drainage amount, so that the water is maintained at the preset liquid level, thereby realizing the flow of water in the drying tank 70.
[0088] S13, slowly pulling the wafer 200 at a preset speed to separate it from the liquid surface of the drying tank 70, and spraying the mixed gas toward the wafer 200 in the drying chamber 10;
[0089] Specifically, the lifting mechanism 22 slowly rises at a preset speed, pulling the wafer 200 out of the liquid surface of the drying tank 70. The portion of the wafer 200 that is out of the liquid surface forms the liquid film. The preset speed may be 1 cm / min to 2 cm / min, for example, 1.5 cm / min.
[0090] As the wafer 200 emerges from the liquid surface, the spray assembly 60 sprays the mixed gas toward the wafer 200. The mixed gas creates a Marangoni effect on the exposed surface of the wafer 200, gradually stripping the liquid film therefrom. This allows the liquid film to be stripped away simultaneously with its formation on the wafer 200, saving time and improving drying efficiency.
[0091] The wafer drying method in this embodiment can not only improve the cleanliness of the wafer 200 , but also improve the drying efficiency.
[0092] In some embodiments, reference Figure 5 , stop introducing the surfactant S2 into the drying chamber 10, specifically including:
[0093] S21 . When the wafer 200 is completely out of the liquid surface, the introduction of the surfactant into the drying chamber 10 is stopped.
[0094] Specifically, a position monitoring device (e.g., an image sensor or distance sensor) can be installed in the drying chamber 10 to monitor the position of the wafer 200 relative to the liquid surface. Based on the monitoring results of the position monitoring device, the controller determines whether the wafer 200 has completely escaped the liquid surface. If so, the controller closes the second valve f2 to stop the flow of surfactant into the drying chamber 10.
[0095] In this way, the use of surfactants can be reduced and costs can be lowered.
[0096] In some embodiments, step S12 of adding water to the drying tank 70 and maintaining the water level at the preset level for a fourth period after the water level reaches a preset level sufficient to submerge the wafers 200 further includes:
[0097] Inert gas is introduced into the drying chamber 10 simultaneously.
[0098] The inert gas introduced here is usually the same as the other inert species contained in the mixed gas in step S1. During the water injection process, the inert gas is introduced into the drying chamber 10 to ensure the cleanliness of the drying chamber 10.
[0099] It is understandable that in step S12 , when the inert gas is introduced into the drying chamber 10 , the exhaust device 80 is turned on to maintain the air pressure in the drying chamber 10 at atmospheric pressure.
[0100] In some embodiments, reference Figure 5 Before the step of starting the vacuum pump 30 connected to the drying chamber 10, the method includes:
[0101] S5. Increase the flow rate of the hot inert gas to drain the water in the drying tank 70.
[0102] Specifically, wafer drying apparatus 100 includes a drain valve connected to drying tank 70. The drain valve is located on drain pipe 72, and a controller is connected to the drain valve. The controller controls the drain valve to open, connecting drying tank 70 to the outside world, allowing water in drying tank 70 to drain completely out of drying tank 70 through drain pipe 72.
[0103] Here, increasing the flow rate of the hot inert gas is increasing the flow rate of the inert gas in step S5. Specifically, the controller controls the first valve f1 to increase its opening.
[0104] In this embodiment, during the drainage process, hot inert gas is introduced at a large flow rate to prevent the water from being drained too quickly and causing splashing that could contaminate the wafer 200 .
[0105] Specifically in the embodiment, adjusting the flow rate of the hot inert gas to first set the internal pressure of the drying chamber to a first pressure and maintain it for a first time, and then setting the internal pressure of the drying chamber to a second pressure and maintain it for a second time, includes:
[0106] S31, reducing the flow rate of the hot inert gas to make the internal pressure of the drying chamber 10 a first pressure and maintaining it for a first time period;
[0107] Here, the flow rate of the hot inert gas is reduced based on the flow rate of the hot inert gas in step S5.
[0108] S32: Increase the flow rate of the hot inert gas to make the internal pressure of the drying chamber 10 a second pressure and maintain it for a second time period.
[0109] Here, the flow rate of the hot inert gas is increased based on the flow rate of the hot inert gas in step S31.
[0110] In some embodiments, reference Figure 5 , increasing the flow rate of the hot inert gas and maintaining it for a third time, and then shutting down the vacuum pump 30 after step S4, further comprising:
[0111] S6. When the internal pressure of the drying chamber 10 reaches atmospheric pressure, the introduction of the hot inert gas is stopped.
[0112] After the vacuum pump 30 is turned off, hot inert gas is continuously introduced to make the internal pressure of the drying chamber 10 equal to atmospheric pressure, so as to facilitate opening the drying chamber 10 and taking out the wafer 200 .
[0113] In some embodiments, after a liquid film is formed on the surface of the wafer 200 to be dried in the drying chamber 10 , before step S1 of introducing a mixed gas into the drying chamber 10 and spraying it toward the surface of the wafer 200 to remove the liquid film, the process further includes:
[0114] S8. Inert gas is introduced into the drying chamber 10 and the exhaust device 80 is turned on.
[0115] At this time, the inert gas can be a room temperature gas. Before drying, the inert gas is used to purge the drying chamber 10 to remove particulate impurities in the drying chamber 10, thereby improving the cleanliness of the drying chamber 10 and improving the quality of the wafers 200.
[0116] In a specific embodiment of the present application, the process of the wafer drying method is as follows:
[0117] In the first step, nitrogen is introduced into the drying chamber 10 and the exhaust device 80 is turned on;
[0118] In the second step, the wafer 200 to be dried is placed in the drying tank 70 of the drying chamber 10, and water is poured into the drying tank 70. After the water overflows, water is continued to be poured for a fourth time. During this process, nitrogen gas at room temperature is simultaneously introduced.
[0119] In the third step, the wafer 200 is slowly pulled up at a speed of 1 cm / min to separate it from the liquid surface of the drying tank 70, and a mixed gas of hot nitrogen and hot IPA is introduced into the drying chamber 10;
[0120] Step 4: When the wafer 200 is completely out of the liquid surface, stop adding hot IPA;
[0121] Step 5: drain the water in the drying tank 70 and increase the hot nitrogen flow rate;
[0122] In the sixth step, after turning on the vacuum pump 30, the process is repeated twice: first, the hot nitrogen flow rate is reduced to make the internal pressure of the drying chamber 10 the first pressure and maintained for 1 minute; then, the hot nitrogen flow rate is increased to make the internal pressure of the drying chamber 10 the second pressure and maintained for 30 seconds.
[0123] Step 7: Increase the hot nitrogen flow rate and maintain it for 6 minutes, then turn off the vacuum pump 30.
[0124] In the eighth step, when the pressure in the drying chamber 10 returns to atmospheric pressure, the introduction of hot nitrogen is stopped.
[0125] Step 9: Take out the wafer 200.
[0126] It is understandable that the controller in the wafer drying device in the embodiment of the present application can execute the wafer drying method in any of the above embodiments. The wafer drying device includes all the above-mentioned beneficial effects.
[0127] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.
[0128] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be determined by the appended claims.
Claims
1. A wafer drying method, characterized in that: include: In a drying chamber, after a liquid film is formed on the surface of a wafer to be dried, a mixed gas is introduced into the drying chamber and sprayed toward the wafer surface to peel off the liquid film; the mixed gas includes a hot inert gas and a hot surfactant; stopping the introduction of the hot surfactant into the drying chamber; Turning on a vacuum pump connected to the drying chamber and adjusting the flow rate of the hot inert gas to first set the pressure inside the drying chamber to a first pressure and maintain it for a first time, then set the pressure inside the drying chamber to a second pressure and maintain it for a second time, repeating this process N times; the first pressure being a vacuum pressure, and the second pressure being higher than the first pressure; The flow rate of the hot inert gas is increased and maintained for a third period of time, and then the vacuum pump is turned off.
2. The wafer drying method according to claim 1, wherein: In a drying chamber, after a liquid film is formed on the surface of a wafer to be dried, a mixed gas is introduced into the drying chamber and sprayed toward the surface of the wafer to peel off the liquid film, specifically comprising: placing the wafer to be dried in the drying tank of the drying chamber; Filling water into the drying tank, and after the liquid level reaches a preset level that submerges the wafers, continuing to fill water for a fourth period of time and maintaining the liquid level at the preset level; The wafer is slowly pulled up at a preset speed to separate it from the liquid surface of the drying tank, and the mixed gas is sprayed toward the wafer in the drying chamber.
3. The wafer drying method according to claim 2, wherein: Stopping the introduction of the surfactant into the drying chamber specifically includes: When the wafer is completely out of the liquid surface, the introduction of the surfactant into the drying chamber is stopped.
4. The wafer drying method according to claim 2, wherein: The preset speed is 1 cm / min to 2 cm / min.
5. The wafer drying method according to claim 2, wherein: The step of filling water into the drying tank, and after the liquid level reaches a preset liquid level that submerges the wafers, continuing to fill water for a fourth period of time and maintaining the liquid level at the preset liquid level further includes: Inert gas is introduced into the drying chamber simultaneously.
6. The wafer drying method according to claim 5, characterized in that: Before the step of starting the vacuum pump connected to the drying chamber, the method includes: The flow rate of the hot inert gas is increased to drain the water in the drying tank.
7. The wafer drying method according to claim 6, wherein: Adjusting the flow rate of the hot inert gas to first set the internal pressure of the drying chamber to a first pressure and maintain it for a first time, and then setting the internal pressure of the drying chamber to a second pressure and maintain it for a second time, comprises: reducing the flow rate of the hot inert gas so that the pressure inside the drying chamber reaches the first pressure and maintains it for a first time period; The flow rate of the hot inert gas is increased to make the internal pressure of the drying chamber the second pressure and maintain it for a second time period.
8. The wafer drying method according to claim 1, wherein: After increasing the flow rate of the hot inert gas and maintaining it for a third time period, and then shutting down the vacuum pump, the process further includes: When the internal pressure of the drying chamber reaches atmospheric pressure, the introduction of the hot inert gas is stopped.
9. The wafer drying method according to claim 1, wherein: After a liquid film is formed on the surface of the wafer to be dried in the drying chamber, before the step of introducing a mixed gas into the drying chamber and spraying it toward the wafer surface to peel off the liquid film, the method further includes: Introduce inert gas into the drying chamber and turn on the exhaust device.
10. A wafer drying device, characterized in that: The device comprises a drying chamber, a supporting assembly, a vacuum pump, a first flow path, a second flow path, a first valve provided on the first flow path, a second valve provided on the second flow path, an injection assembly and a controller; The first flow path is used to circulate inert gas, and the second flow path is used to circulate vaporized surfactant; The spray assembly and the support assembly are located in the drying chamber, the support assembly is used to support the wafer, the spray assembly is connected to the first flow path and the second flow path, and is used to spray a mixed gas formed by the inert gas and the surfactant onto the wafer on the support assembly; the vacuum pump is connected to the drying chamber and the atmosphere; The controller controls the connection between the first valve, the second valve, and the vacuum pump, and is capable of executing the wafer drying method according to any one of claims 1 to 9.