Device and method for preparing wafer with saturated natural oxide film

Abstract

The invention provides a wafer preparation device and method with a saturated natural oxide film, and belongs to the technical field of semiconductor devices and preparation thereof. The device comprises a chamber, the chamber is connected with a temperature controller and a humidity controller, a support frame, a gas delivery pipe and a wafer are arranged in the chamber, the gas delivery pipe is connected with the support frame, the wafer is arranged on the support frame, and an illumination device is fixed on the support frame. According to the invention, the formation period of the saturated natural oxide film on the surface of the wafer is shortened to improve the complexity of the process, and the formed oxide film is good in uniformity, thereby facilitating the monitoring of thickness measurement equipment.

Description

Technical Field

[0001] This application belongs to the technical field of semiconductor devices and their manufacturing, and particularly relates to a wafer preparation device and method with a saturated natural oxide film. Background Art

[0002] In semiconductor manufacturing and related fields, forming a saturated natural oxide layer on the wafer surface is an important step. This natural oxide layer can not only serve as a protective layer to prevent further oxidation of the wafer surface, but also provide a relatively uniform surface for subsequent processes such as deposition or lithography, facilitating the preparation process.

[0003] However, the existing forming methods have technical problems such as long cycle time and complex operation. Summary of the Invention

[0004] The technical objective of this application is to at least solve the technical problems of long cycle time and complex operation existing in the formation of a saturated natural oxide film on the silicon wafer surface. For this purpose, this application provides a silicon wafer preparation device and method with a saturated natural oxide film. This application improves the complexity of the process by shortening the formation cycle of the saturated natural oxide film on the wafer surface, and the formed oxide film has good uniformity, facilitating the monitoring of thickness measurement equipment.

[0005] The first aspect of this application is to provide a wafer preparation device with a saturated natural oxide film, including:

[0006] Chamber: Connected to a temperature controller and a humidity controller;

[0007] Support frame: Disposed in the above chamber and including support beams. The support beams include a longitudinal main support beam and a plurality of transverse support beams, and each transverse support beam is respectively connected to the longitudinal main support beam;

[0008] Wafer: Placed on the above transverse support beam;

[0009] Lighting device: Fixed on the above transverse support beam and facing the above wafer;

[0010] Gas supply pipe: Connected to the above support frame, and one end of the gas supply pipe is connected to a gas storage device, and the other end of the gas supply pipe is connected to a plurality of nozzles. Each nozzle is spaced on the support beam, and each nozzle faces the wafer surface.

[0011] In some embodiments, the gas storage device contains any one or more of air, oxygen, nitrogen oxides, and nitrogen;

[0012] In some embodiments, a flow control valve is provided on the above gas supply pipe.

[0013] In some embodiments, the longitudinal support main beam is arranged perpendicular to the transverse support beam.

[0014] In some embodiments, a manipulator is provided in the chamber, and the manipulator is used to grasp the wafer and flip the wafer.

[0015] In some embodiments, the chamber includes an air inlet and an air outlet, and the gas pipeline is connected to the gas storage device through the air inlet.

[0016] The second aspect of the present application is to provide a method for preparing a natural oxide film on the surface of a wafer. The method uses the device described in the first aspect and performs the following process:

[0017] Perform surface etching treatment on the wafer sample with a hydrofluoric acid solution to generate a wafer with surface roughness;

[0018] Turn on the temperature controller, humidity controller, lighting device and nozzle of the above device;

[0019] Place the wafer with surface roughness on the transverse support beam of the above device;

[0020] Monitor the thickness of the natural oxide film on the surface of the wafer, and the preparation is completed when the average thickness remains unchanged.

[0021] In some embodiments, the step of performing surface etching treatment on the wafer sample with the hydrofluoric acid solution includes:

[0022] Perform surface cleaning treatment on the wafer sample;

[0023] Immerse the wafer after cleaning treatment in a hydrofluoric acid solution with a mass concentration of 1% to 10% for 1 minute to 5 minutes;

[0024] Take out the etched wafer, wash it with ultrapure water multiple times, and dry it;

[0025] Check the etching situation.

[0026] In some embodiments, after the surface etching treatment, the surface roughness of the wafer is 0.001 nm to 0.1 nm.

[0027] In some embodiments, control the temperature of the chamber to be 22°C to 24°C and the humidity to be 40% to 50%;

[0028] and / or;

[0029] The illumination intensity of the above lighting device is 50 Lux to 150 Lux.

[0030] In some embodiments, air or a mixture of oxygen, nitrogen oxides, and nitrogen is introduced into the chamber through the above nozzle.

[0031] Advantageous technical effects of the present application:

[0032] 1. The preparation device for forming a saturated natural oxide film on the surface of a wafer provided by the present application is convenient to operate.

[0033] 2. The preparation method for forming a saturated natural oxide film on the surface of a wafer provided by the present application not only shortens the formation period. For example, the period for generating a saturated natural oxide film by the existing conventional method is about 1 year, while the design method provided by the present application can be completed in about 6 months. Moreover, the formed oxide film has good uniformity and no difference in surface quality from the existing conventional method, which further facilitates the monitoring of thickness measurement equipment. Description of the Drawings

[0034] By reading the following detailed description of the preferred embodiments, various other advantages and benefits will become clear to those of ordinary skill in the art. The drawings are only for the purpose of showing the preferred embodiments and are not considered to be a limitation of the present application. Moreover, throughout the drawings, the same reference numerals are used to represent the same components. In the drawings:

[0035] Figure 1 Schematically shows a structural diagram of a device according to some embodiments of the present application;

[0036] Figure 2 Schematically shows another structural diagram of a device according to some embodiments of the present application;

[0037] Figure 3 Schematically shows another structural diagram of a device according to some embodiments of the present application;

[0038] Figure 4 Schematically shows a process flow diagram of a method according to some embodiments of the present application;

[0039] Figure 5 Schematically shows a process flow diagram of a method according to some embodiments of the present application;

[0040] The component numbers in the above drawings are as follows:

[0041] 1000, preparation device;

[0042] 100, chamber; 110, air inlet; 120, air outlet;

[0043] 200, support frame; 210, support beam; 210a, longitudinal support main beam; 210b, transverse support beam;

[0044] 220, gas pipeline; 230, nozzle; 240, lighting device;

[0045] 300, wafer;

[0046] 400, manipulator;

[0047] 500, temperature controller;

[0048] 600, humidity controller;

[0049] 700, gas storage device. Detailed implementation manners

[0050] In order to make the objectives, technical solutions and advantages of the present application clearer and more understandable, the present application will be further described below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the scope of protection of the present application.

[0051] In the drawings, various structural schematic diagrams according to embodiments of the present application are shown. These figures are not drawn to scale, where for the purpose of clear expression, some details are enlarged and some details may be omitted. The shapes of various regions and layers shown in the figures, as well as their relative sizes and positional relationships, are only exemplary. In practice, there may be deviations due to manufacturing tolerances or technical limitations, and those skilled in the art can design regions / layers with different shapes, sizes and relative positions according to actual needs.

[0052] In the context of the present application, when a layer / component is referred to as being "on" another layer / component, the layer / component can be directly on the other layer / component, or there can be an intermediate layer / component between them. Additionally, if a layer / component is "on" another layer / component in one orientation, then when the orientation is reversed, the layer / component can be "under" the other layer / component.

[0053] The present application may use the term "coupled with" and its derivatives. "Coupled" can mean one or more of the following. "Coupled" can mean that two or more elements are in direct physical or electrical contact. However, "coupled" can also mean that two or more elements are in indirect contact with each other, but still cooperate or interact with each other, and can mean that one or more other elements are coupled or connected between the elements said to be coupled to each other. The term "directly coupled" can mean that two or more elements are in direct contact.

[0054] In semiconductor manufacturing and related fields, forming a saturated natural oxide layer on the surface of a wafer is an important step. Specifically, the wafer is placed in a natural state for a period of time to form a natural oxide layer with a fine thickness on its surface.

[0055] This natural oxide film can not only serve as a protective layer to prevent the surface of the wafer from being further oxidized by oxygen or water vapor in the atmosphere, thus maintaining the stability and consistency of the wafer surface, but also provide a relatively uniform surface for subsequent processes such as deposition or lithography. For example, before depositing other materials, the saturated natural oxide film can act as a buffer layer to improve the adhesion and growth quality of the film to be deposited.

[0056] However, the existing formation methods have technical problems such as long cycle time and complex operation. Specifically, the existing natural growth takes about one year. The long waiting time results in an overly long sample preparation cycle, affecting the monitoring efficiency and production progress of semiconductor manufacturing equipment. Moreover, the samples need to be stored in a specific place, which increases the demand for storage space and management costs. In addition, since the samples cannot be put into use in time, it may lead to delays in the monitoring and calibration of thickness measurement equipment, thus affecting the accuracy and quality control of semiconductor manufacturing.

[0057] To solve the above technical problems, the present application discloses a wafer preparation device and method with a saturated natural oxide film. The present application improves the complexity of the process by shortening the formation cycle of the saturated natural oxide film on the wafer surface, and the formed oxide film has good uniformity, which is convenient for the monitoring of thickness measurement equipment.

[0058] The first aspect of the present application is to provide a wafer preparation device with a saturated natural oxide film, as Figure 1 shown in the schematic. The preparation device 1000 includes a chamber 100, which is connected to a temperature controller 500 and a humidity controller 600. A support frame 200 is arranged in the chamber 100. The support frame 200 includes a support beam 210, and the support beam 210 includes a longitudinal support main beam 210a and a plurality of transverse support beams 210b. Each transverse support beam 210b is respectively connected to the above longitudinal support main beam 210a. A wafer 300 is also placed in the chamber 100, and the wafer 300 is placed on the above transverse support beam 210b. A lighting device 240 is also fixedly arranged on the transverse support beam 210b, and the lighting device 240 is arranged facing the above wafer 300. The above preparation device 1000 also includes an air delivery pipe 220, which is connected to the support frame 200. Among them, one end of the air delivery pipe 220 is connected to a gas storage device 700, and the other end of the air delivery pipe 220 is connected to a plurality of nozzles 230. Each nozzle 230 is arranged at intervals on the above support beam 210, and each nozzle 230 is arranged facing the surface of the above wafer 300.

[0059] The natural oxide film of the present application refers to a surface film state that is the same as or similar to the surface film with a fine thickness formed on the wafer in a natural environment.

[0060] "Saturation" in this application refers to the stable state of the surface oxide film, that is, the growth of the oxide film has been completed and will not continue to grow naturally, thus ensuring the stability and consistency of the wafer during subsequent use. In some embodiments of this application, it is used to indicate that the average thickness of the surface oxide film no longer changes, i.e., it reaches saturation.

[0061] "Wafer" in this application refers to a silicon dioxide wafer used for semiconductor manufacturing.

[0062] The temperature controller and humidity controller in this application generally include a sensor, a controller, and an actuator. Among them, the sensor is used to detect the temperature and humidity values and convert them into electrical signals; the controller is responsible for receiving the signals sent by the sensor and controlling the operation of the actuator accordingly to keep the temperature and humidity stable. The actuator is usually a device such as a heater, a cooler, or a humidifier, which executes the instructions issued by the controller.

[0063] The temperature controller in this application is used to control and maintain the temperature in the chamber at a certain level. Similarly, the humidity controller in this application is used to control and maintain the humidity in the chamber at a certain level.

[0064] The support frame in this application can be fixedly arranged in the chamber or can be movably connected in the chamber. For example, the longitudinal support main beam of the support frame can rotate along its central axis, and in this case, a rotatable bearing needs to be provided at the bottom end of the longitudinal support main beam. Or, the transverse support beam can rotate circumferentially along the longitudinal support main beam, and in this case, a universal shaft is installed between the transverse support beam and the longitudinal support main beam.

[0065] The lighting device in this application is used to provide a certain amount of light to the chamber and further provide heat and light to the wafer surface. The lighting device includes any conventional lighting lamp in the art.

[0066] Therefore, the device provided in this application shortens the formation period of the saturated natural oxide film on the wafer surface. For example, the period for generating the saturated natural oxide film by the existing conventional method is about 1 year, while the design method provided in this application can be completed in about 6 months. Moreover, the formed oxide film has good uniformity and no difference in surface quality from the existing conventional method, which further facilitates the monitoring of the thickness measurement device.

[0067] In some embodiments, the above-mentioned gas storage device contains any one or more of air, oxygen, nitrogen oxides, and nitrogen.

[0068] The types of gases listed above in this application mainly serve as reaction raw materials for the oxide film.

[0069] In some embodiments, a flow control valve is provided on the above-mentioned gas pipeline.

[0070] The flow control valve in this application facilitates the control of the amount of gas in the chamber and is used to maintain the gas balance in the system.

[0071] In some embodiments, the longitudinal support main beam and the transverse support beam are arranged perpendicular to each other.

[0072] This application Figure 1 shows a schematic structural diagram of a device, and Figure 3 shows another schematic structural diagram. Combining Figure 1 and Figure 3 it can be seen that the longitudinal support main beam 210a and the transverse support beam 210b of this application are arranged perpendicular to each other, and this design method facilitates the transverse support beam to support the wafer 300.

[0073] In some embodiments, a manipulator is provided in the chamber, and the manipulator is used to grasp the wafer and flip the wafer.

[0074] This application Figure 2 shows the manipulator 400. The shape of the manipulator is any conventional shape in the art. For example, it includes a chuck, a moving arm connecting the chuck, and a power mechanism for driving the moving arm and the chuck. This manipulator facilitates grasping the wafer and flipping the wafer. In some embodiments of this application, a manipulator is provided in the chamber because part of the surface of the wafer is in contact with the transverse support beam, resulting in a slow oxidation film formation rate on this part, so the surface quality of the entire wafer is uneven. This application selects to ensure the uniformity of the surface quality of the wafer, so a manipulator is used to flip the wafer at a certain time.

[0075] In some embodiments, the chamber includes an air inlet and an air outlet, and the gas transmission pipe is connected to the gas storage device through the air inlet.

[0076] This application Figure 1 、 Figure 2 and Figure 3 respectively show the air inlet 110 and the air outlet 120 on the chamber 100. The gas transmission pipe 220 of this application is connected to the gas storage device 700 through the air inlet 110.

[0077] The second aspect of this application is to provide a method for preparing a natural oxide film on the surface of a wafer. This method uses the device described in the first aspect and performs the Figure 4 process shown:

[0078] S100. Perform surface etching treatment on the wafer sample with hydrofluoric acid solution to generate a wafer with surface roughness;

[0079] S200. Turn on the temperature controller, humidity controller, lighting device and nozzle of the above device;

[0080] S300. Place the wafer with the surface roughness on the transverse support beam of the above device;

[0081] S400. Monitor the thickness of the natural oxide film on the surface of the wafer. Once the average thickness remains unchanged, the preparation is completed.

[0082] In some embodiments, the steps of surface etching treatment of the wafer sample with the above hydrofluoric acid solution are as Figure 5 shown. The specific steps are as follows:

[0083] S110. Perform surface cleaning treatment on the wafer sample;

[0084] S120. Immerse the wafer after cleaning treatment in a hydrofluoric acid solution with a mass concentration of 1% - 10% for 1 min - 5 min;

[0085] S130. Take out the etched wafer, wash it with ultrapure water multiple times, and dry it;

[0086] S140. Check the etching situation.

[0087] Step S110 of this application includes: alternately cleaning the surface of the wafer with ultrapure water and isopropanol more than three times in sequence to remove dust and organic pollutants.

[0088] Step S120 of this application includes stirring the hydrofluoric acid solution to avoid too high or too low local concentration.

[0089] The drying in step S130 of this application includes: using a nitrogen gun to blow dry the surface of the wafer.

[0090] Step S140 of this application includes using an optical microscope or a scanning electron microscope (SEM) to check the etching effect on the surface of the wafer and confirm whether the surface roughness or etching depth meets the requirements.

[0091] In some embodiments, after the surface etching treatment, the surface roughness of the above wafer is 0.001 nm - 0.1 nm.

[0092] The roughness in this application includes the unevenness of the smaller spacing and tiny peaks and valleys on the deposited surface. Generally speaking, the smaller the surface roughness, the smoother the surface. The roughness in this application includes the arithmetic mean deviation of the profile Ra, and its value can be obtained with reference to GB / T 131 - 2006.

[0093] This application controls the surface roughness of the wafer after etching to be 0.001 nm - 0.1 nm to facilitate the subsequent formation of an oxide film in the chamber.

[0094] In these embodiments, the present application discloses that the surface roughness of the above-mentioned wafer is any one of 0.001 nm, 0.002 nm, 0.003 nm, 0.004 nm, 0.005 nm, 0.006 nm, 0.007 nm, 0.008 nm, 0.009 nm, 0.01 nm, 0.02 nm, 0.03 nm, 0.04 nm, 0.05 nm, 0.06 nm, 0.07 nm, 0.08 nm, 0.09 nm, 0.1 nm or any one that satisfies the range values of any two of the above.

[0095] In some embodiments, the temperature of the above-mentioned chamber is controlled to be 22°C to 24°C, and the humidity is 40% to 50%.

[0096] The present application creates a good natural environment for generating an oxide film by controlling the temperature and humidity of the chamber, which facilitates the generation of the oxide film.

[0097] The humidity in the present application refers to the relative humidity, which is the ratio of the actual amount of water vapor contained in the air to the saturated water vapor amount at a specific temperature, usually expressed as a percentage. It has a significant impact on the growth rate and quality of the oxide film. By precisely controlling the relative humidity, the present application can significantly accelerate the growth of the oxide film and improve the efficiency and quality of wafer preparation. At the same time, the relative humidity in the present application, together with temperature, gas composition, etc., jointly affects the growth of the oxide film.

[0098] In these embodiments, the present application discloses that the temperature of the above-mentioned chamber is controlled to be any one or more of 22.0°C, 22.1°C, 22.2°C, 22.3°C, 22.4°C, 22.5°C, 22.6°C, 22.7°C, 22.8°C, 22.9°C, 23.0°C, 23.1°C, 23.2°C, 23.3°C, 23.4°C, 23.5°C, 23.6°C, 23.7°C, 23.8°C, 23.9°C, 24.0°C.

[0099] In these embodiments, the present application discloses that the humidity of the chamber is any one of 40%, 41%, 42%, 43%, 44%, 45%, 46%, 47%, 48%, 49%, 50% or any one that satisfies the range values of any two of the above.

[0100] In some embodiments, the illumination intensity of the above-mentioned illumination device is 50 Lux to 150 Lux.

[0101] The illumination intensity of the present application promotes the progress of the oxidation reaction by providing energy (in the form of photons), and can also adjust the growth rate and quality of the oxide film. In these embodiments, the present application controls the illumination intensity of the illumination device to be 50 Lux to 150 Lux (lux) to facilitate controlling the growth rate and quality of the oxide film.

[0102] In these embodiments of the present application, the illumination intensity of the above-mentioned illumination device is any one of 50 Lux, 51 Lux, 52 Lux, 53 Lux, 54 Lux, 55 Lux, 56 Lux, 57 Lux, 58 Lux, 59 Lux, 60 Lux, 61 Lux, 62 Lux, 63 Lux, 64 Lux, 65 Lux, 66 Lux, 67 Lux, 68 Lux, 69 Lux, 70 Lux, 71 Lux, 72 Lux, 73 Lux, 74 Lux, 75 Lux, 76 Lux, 77 Lux, 78 Lux, 79 Lux, 80 Lux, 81 Lux, 82 Lux, 83 Lux, 84 Lux, 85 Lux, 86 Lux, 87 Lux, 88 Lux, 89 Lux, 90 Lux, 91 Lux, 92 Lux, 93 Lux, 94 Lux, 95 Lux, 96 Lux, 97 Lux, 98 Lux, 99 Lux, 100 Lux, 101 Lux, 102 Lux, 103 Lux, 104 Lux, 105 Lux, 106 Lux, 107 Lux, 108 Lux, 109 Lux, 110 Lux, 111 Lux, 112 Lux, 113 Lux, 114 Lux, 115 Lux, 116 Lux, 117 Lux, 118 Lux, 119 Lux, 120 Lux, 121 Lux, 122 Lux, 123 Lux, 124 Lux, 125 Lux, 126 Lux, 127 Lux, 128 Lux, 129 Lux, 130 Lux, 131 Lux, 132 Lux, 133 Lux, 134 Lux, 135 Lux, 136 Lux, 137 Lux, 138 Lux, 139 Lux, 140 Lux, 141 Lux, 142 Lux, 143 Lux, 144 Lux, 145 Lux, 146 Lux, 147 Lux, 148 Lux, 149 Lux, 150 Lux or any one that satisfies any two of the above range values.

[0103] In some embodiments, air or a mixture of oxygen, nitrogen oxides, and nitrogen is introduced into the above-mentioned chamber through the above-mentioned nozzle.

[0104] As described above, the gas introduced in the present application is mainly used as a reaction raw material for the oxide film. In these embodiments of the present application, the pressure in the chamber is the standard atmospheric pressure.

[0105] In some embodiments, an atomic force microscope (AFM) is used to monitor that the thickness of the natural oxide film on the surface of the above-mentioned wafer is 500 nm to 1 μm. In these embodiments, the present application further discloses that the thickness of the oxide film is measured every about 10 days. When it is found that the thickness of the oxide film no longer changes after more than three measurements, it is determined that the preparation is completed, and the wafer can be taken out of the chamber.

[0106] Example 1

[0107] A method for preparing a natural oxide film on the surface of a wafer is provided. This method is carried out in the Figure 2 device shown in the schematic diagram, and includes the following steps:

[0108] S110. Clean the surface of the wafer three times in turn with ultrapure water and isopropyl alcohol to remove dust and organic contaminants;

[0109] S120. Immerse the cleaned wafer in a hydrofluoric acid solution with a mass concentration of 5% for 2.5 min; and stir the hydrofluoric acid solution during the treatment, and control the stirring speed to be 100 revolutions per minute;

[0110] S130. Take out the corroded wafer, wash it five times with ultrapure water, and use a nitrogen gun to dry the surface of the wafer;

[0111] S140. Use a scanning electron microscope to check the corrosion effect on the surface of the wafer, and measure the surface roughness of the wafer to be 0.05 nm according to GB / T 131-2006;

[0112] S200. Turn on the temperature controller, humidity controller, lighting device and nozzle of the above-mentioned device;

[0113] S300. Place the wafer with the above-mentioned surface roughness on the horizontal support beam of the above-mentioned device, control the temperature of the above-mentioned chamber to be 23.3°C ± 0.1°C, and the humidity to be 45% ± 1%; the illumination intensity of the above-mentioned lighting device is 105 Lux ± 1 Lux;

[0114] Every half month, use the Figure 2 manipulator in to turn over each wafer;

[0115] S400. Use an atomic force microscope to monitor the thickness of the natural oxide film on the surface of the above-mentioned wafer. When the average thickness remains unchanged, the preparation is completed. The thickness of the natural oxide film on the surface of the above-mentioned wafer is monitored to be 850 nm ± 3 nm, and the time required from placing the wafer in the chamber to generating a saturated oxide film is 135 days.

[0116] Example 2

[0117] A method for preparing a natural oxide film on the surface of a wafer is provided. This method is carried out in the Figure 3It is carried out in the schematic device, and other aspects are the same as those in Embodiment 1.

[0118] Finally, the thickness of the natural oxide film on the surface of the above-mentioned wafer is monitored in S400 to be 850 nm ± 3 nm, and the time required from placing the wafer in the chamber to generating a saturated oxide film is 190 days.

[0119] Embodiment 3

[0120] A method for preparing a natural oxide film on the surface of a wafer is provided. This method is carried out in Figure 2 the schematic device, and the difference between this method and Embodiment 1 is that:

[0121] S120. Immerse the wafer after cleaning treatment in a hydrofluoric acid solution with a mass concentration of 1% for 2.5 min; and stir the hydrofluoric acid solution during the treatment process, and control the stirring speed to be 100 revolutions per minute;

[0122] S140. Use a scanning electron microscope to check the corrosion effect on the surface of the wafer, and measure the surface roughness of the wafer to be 0.002 nm according to GB / T 131-2006;

[0123] S400. Use an atomic force microscope to monitor the thickness of the natural oxide film on the surface of the above-mentioned wafer. When the average thickness remains unchanged, the preparation is completed. The thickness of the natural oxide film on the surface of the above-mentioned wafer is monitored to be 820 nm ± 3 nm, and the time required from placing the wafer in the chamber to generating a saturated oxide film is 180 days.

[0124] Embodiment 4

[0125] A method for preparing a natural oxide film on the surface of a wafer is provided. This method is carried out in Figure 2 the schematic device, and the difference between this method and Embodiment 1 is that:

[0126] S120. Immerse the wafer after cleaning treatment in a hydrofluoric acid solution with a mass concentration of 9% for 2.5 min; and stir the hydrofluoric acid solution during the treatment process, and control the stirring speed to be 100 revolutions per minute;

[0127] S140. Use a scanning electron microscope to check the corrosion effect on the surface of the wafer, and measure the surface roughness of the wafer to be 0.1 nm according to GB / T 131-2006;

[0128] S400. Use an atomic force microscope to monitor the thickness of the natural oxide film on the surface of the above-mentioned wafer. When the average thickness remains unchanged, the preparation is completed. The thickness of the natural oxide film on the surface of the above-mentioned wafer is monitored to be 860 nm ± 5 nm, and the time required from placing the wafer in the chamber to generating a saturated oxide film is 140 days.

[0129] Embodiment 5

[0130] A method for preparing a natural oxide film on the surface of a wafer is provided. This method is carried out in the Figure 2 device shown in the schematic diagram, and the difference between this method and Example 1 is that:

[0131] S300. Place the wafer with the above-mentioned surface roughness on the lateral support beam of the above-mentioned device, control the temperature of the above-mentioned chamber to be 22.5°C ± 0.1°C, and the humidity to be 40% ± 1%; the light intensity of the above-mentioned lighting device is 55 Lux ± 1 Lux;

[0132] S400. Use an atomic force microscope to monitor the thickness of the natural oxide film on the surface of the above-mentioned wafer. Wait until the average thickness remains unchanged, then the preparation is completed. The monitored thickness of the natural oxide film on the surface of the above-mentioned wafer is 850 nm ± 3 nm, and the time required from placing the wafer in the chamber to generating a saturated oxide film is 200 days.

[0133] Comparative Example 1

[0134] A method for forming a saturated natural oxide film on the surface of a wafer is provided:

[0135] Place the wafer sample without any treatment in Example 1 in the natural environment. Monitor the thickness of the natural oxide film on the surface of the above-mentioned wafer every 2 months using an atomic force microscope.

[0136] The time required from placing the wafer in the chamber to generating a saturated oxide film is 1 year + 35 days, and the monitored thickness of the natural oxide film on the surface of the above-mentioned wafer is 800 nm ± 5 nm.

[0137] Comparative Example 2

[0138] A method for forming a saturated natural oxide film on the surface of a wafer is provided. The difference between this method and Example 1 is that it does not have step S100, and other aspects are the same as Example 1.

[0139] The time required from placing the wafer in the chamber to generating a saturated oxide film is 290 days, and the monitored thickness of the natural oxide film on the surface of the above-mentioned wafer is 805 nm ± 5 nm.

[0140] Combining the above-mentioned examples and comparative examples, it can be seen that this application improves the complexity of the process by shortening the formation cycle of the saturated natural oxide film on the wafer surface, and the formed oxide film has good uniformity, which is convenient for monitoring by thickness measurement equipment.

[0141] In the above description, no detailed explanations are given for the technical details such as the composition and etching of each layer. However, those skilled in the art should understand that various technical means can be used to form layers, regions, etc. of the desired shapes. Additionally, to form the same structure, those skilled in the art can also design methods that are not exactly the same as the methods described above. Moreover, although the embodiments are described separately above, this does not mean that the measures in each embodiment cannot be used advantageously in combination.

[0142] The embodiments of the present application have been described above. However, these embodiments are merely for illustrative purposes and

[0143] are not intended to limit the scope of the present application. The scope of the present application is defined by the appended claims and their equivalents. Without departing from the scope of the present application, those skilled in the art can make various substitutions and modifications, and all such substitutions and modifications should fall within the scope of the present application.

Claims

1. A wafer preparation device with a saturated natural oxide film, characterized in that: Comprising: Chamber: Connecting a temperature controller and a humidity controller; Support frame: Arranged inside the chamber and including support beams, the support beams including a longitudinal support main beam and a plurality of transverse support beams, each of the transverse support beams being respectively connected to the longitudinal support main beam; Wafer: Placed on the transverse support beam; Lighting device: Fixed on the transverse support beam and arranged facing the wafer; Gas delivery pipe: Connected to the support frame, and one end of the gas delivery pipe is connected to a gas storage device, the other end of the gas delivery pipe is connected to a plurality of nozzles, each of the nozzles being spaced apart on the support beam, and each nozzle being arranged facing the surface of the wafer.

2. The preparation device according to claim 1, characterized in that: The gas storage device contains any one or more of air, oxygen, nitrogen oxides, and nitrogen; Preferably, a flow control valve is provided on the gas delivery pipe.

3. The preparation device according to claim 1, characterized in that: The longitudinal support main beam and the transverse support beams are perpendicularly arranged.

4. The preparation device according to claim 1, wherein: A manipulator is provided inside the chamber, and the manipulator is used to grasp the wafer and flip the wafer.

5. The preparation device according to claim 1, wherein: The chamber includes an air inlet and an air outlet, and the gas delivery pipe is connected to the gas storage device through the air inlet.

6. A method for preparing a natural oxide film on the surface of a wafer, characterized in that: The method uses the device described in claim 1 and performs the following process: Performing a surface etching treatment on a wafer sample with a hydrofluoric acid solution to generate a wafer with surface roughness; Turning on the temperature controller, humidity controller, lighting device, and nozzles of the device; Placing the wafer with surface roughness on the transverse support beam of the device; Monitoring the thickness of the natural oxide film on the surface of the wafer, and the preparation is completed when the average thickness remains unchanged.

7. The method according to claim 6, wherein: The step of performing a surface etching treatment on the wafer sample with the hydrofluoric acid solution includes: Performing a surface cleaning treatment on the wafer sample; Immersing the wafer after the cleaning treatment in a hydrofluoric acid solution with a mass concentration of 1% to 10% for 1 minute to 5 minutes; Taking out the etched wafer, washing it multiple times with ultrapure water, and drying it; Checking the etching condition.

8. The method according to any one of claims 6 to 7, characterized in that: After the surface etching treatment, the surface roughness of the wafer is 0.001 nm to 0.1 nm.

9. The method according to any one of claims 6 to 7, characterized in that: Controlling the temperature of the chamber to be 22°C to 24°C and the humidity to be 40% to 50%; And / or; The lighting intensity of the lighting device is 50 Lux to 150 Lux.

10. The method according to any one of claims 6 to 7, characterized in that: Introducing air or a mixture of oxygen, nitrogen oxides, and nitrogen into the chamber through the nozzles.

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