Wafer processing method and apparatus

Abstract

Embodiments of the present application provide a wafer processing method and apparatus. The wafer processing method comprises: rotating a wafer; spraying first liquid onto the center of the wafer by means of a first nozzle for a preset duration; continuing to spray the first liquid, and spraying second liquid onto the surface of the wafer by means of a second nozzle, a liquid landing point of the second liquid falling between a first position and the center of the wafer, and a centrifugal force applied to the second liquid at the first position being less than a force applied to the second liquid to spread out from the liquid landing point; and stopping spraying the first liquid onto the center of the wafer once the second liquid reaches the center of the wafer.

Description

Wafer processing methods and apparatus

[0001] This application claims priority to Chinese Patent Application No. 202510010070.3, filed on January 2, 2025, the contents of which are incorporated herein by reference in their entirety. Technical Field

[0002] This application relates to the field of semiconductor technology, and more specifically, to a wafer processing method and apparatus. Background Technology

[0003] The manufacturing of semiconductor devices involves multiple processing steps. In the process of processing wafers using processing solutions, a chuck is typically used to hold the wafer horizontally and rotate it around its center while various processing solutions are supplied to the wafer for processing.

[0004] For example, in the wet etching process of wafers, multiple acids are used to treat the wafer. After each acid treatment, a cleaning solution is typically used to wash away any residual acid from the previous step before another acid is used to treat the wafer. The acid washing process may involve the use of multiple cleaning solutions, resulting in steps where acid and cleaning solutions are interchanged, and cleaning solutions are interchanged with each other.

[0005] Acids and cleaning solutions have different viscosities, and different cleaning solutions have different viscosities. These different viscosities diffuse at different rates on the wafer. Therefore, during the process of changing the cleaning solution, areas on the wafer may not be covered by the cleaning solution. When impurities from the environment fall into these uncovered areas, wafer defects will occur. Summary of the Invention

[0006] The embodiments of this application provide a wafer processing method and apparatus that can improve or to some extent avoid the breakage of the liquid film on the wafer surface when changing the processing solution.

[0007] This application provides a wafer protection method, including rotating the wafer; spraying a first liquid onto the wafer center for a preset time through a first nozzle; continuing to spray the first liquid, and spraying a second liquid onto the wafer surface through a second nozzle, wherein the contact point of the second liquid falls between a first position and the wafer center, and the centrifugal force experienced by the second liquid at the first position is less than the force by which the second liquid diffuses outward from the contact point; and stopping spraying the first liquid onto the wafer center after the second liquid reaches the wafer center.

[0008] Specifically, a second position is included between the first position and the wafer center, the contact point of the second liquid falls between the first position and the second position, and the distance between the second position and the wafer center is greater than or equal to the sum of the radius of the first liquid contact point and the radius of the second liquid contact point.

[0009] Specifically, the second nozzle does not move until the second liquid reaches the center of the wafer.

[0010] Specifically, before the second liquid reaches the center of the wafer, the second nozzle is moved to move the contact point of the second liquid toward the second position.

[0011] Specifically, before the liquid film of the second liquid reaches the center of the wafer, the wafer rotates at a first speed, and after the liquid film of the second liquid reaches the center of the wafer, the wafer rotates at a second speed, wherein the first speed is less than the second speed.

[0012] Specifically, before the liquid film of the second liquid reaches the center of the wafer, the second liquid is sprayed at a first flow rate, and after the liquid film of the second liquid reaches the center of the wafer, the second liquid is sprayed at a second flow rate, wherein the first flow rate is greater than the second flow rate.

[0013] Specifically, before the liquid film of the second liquid reaches the center of the wafer, the point of contact of the second liquid is closer to the center of the wafer than the orthogonal projection of the second nozzle onto the wafer.

[0014] Specifically, after stopping the spraying of the first liquid to the center of the wafer, the second liquid is sprayed and the second nozzle is moved to move the contact point of the second liquid to the center of the wafer.

[0015] The wafer processing method and apparatus of this application, by stopping the spraying of the first liquid onto the wafer center only after the liquid film of the second liquid has covered the wafer center, can prevent the liquid film near the wafer center from breaking when the processing liquid of the wafer is changed from the first liquid to the second liquid.

[0016] Other features and advantages of this application will become apparent from the following detailed description, or may be learned in part from practice of this application.

[0017] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit this application.

[0018] Overview of the attached figures

[0019] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application. It is obvious that the drawings described below are merely some embodiments of this application, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort. In the drawings:

[0020] Figure 1 shows a schematic diagram of a wafer processing apparatus according to an embodiment of this application;

[0021] Figure 2 shows a schematic diagram of a wafer processing apparatus according to an embodiment of this application;

[0022] Figure 3 shows a schematic diagram of the wafer processing method provided in this application.

[0023] Among them, 1, wafer; 2, chuck; 3, drive unit; 4, first nozzle; 5, second nozzle; 6, moving assembly; 61, first moving arm; 62, second moving arm.

[0024] Preferred embodiments of the present invention

[0025] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided to make this application more comprehensive and complete, and to fully convey the concept of the exemplary embodiments to those skilled in the art.

[0026] Furthermore, the described features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are provided to give a thorough understanding of embodiments of this application. However, those skilled in the art will recognize that the technical solutions of this application can be practiced without one or more of the specific details, or other methods, components, apparatuses, steps, etc., can be employed. In other instances, well-known methods, apparatuses, implementations, or operations are not shown or described in detail to avoid obscuring various aspects of this application.

[0027] Referring to Figure 1, this embodiment provides a wafer processing apparatus that can prevent areas on wafer 1 from being covered by the processing solution when changing the processing solution, thereby preventing impurities from falling into these areas and causing defects in wafer 1.

[0028] As shown in Figure 1, the wafer processing apparatus includes a rotating unit for rotating a wafer 1, a first nozzle 4 for spraying a first liquid, a second nozzle 5 for spraying a second liquid, and a moving assembly 6. The rotating unit includes a chuck 2 for carrying the wafer 1 and a drive member 3 for rotating the chuck 2. The moving assembly 6 includes a first moving arm 61 and a second moving arm 62. The first moving arm 61 is connected to the first nozzle 4 and is used to move the first nozzle 4 to change the contact point of the first liquid. The second moving arm 62 is connected to the second nozzle 5 and is used to move the second nozzle 5 to change the contact point of the second liquid.

[0029] The wafer processing apparatus also includes a controller electrically connected to a first moving arm 61 for sending a movement signal to the first moving arm 61 to move the first nozzle 4. The controller is also electrically connected to a second moving arm 62 for sending a movement signal to the second moving arm 62 to move the second nozzle 5. The controller is further configured to send signals to the first nozzle 4 and / or the second nozzle 5 to start or stop spraying.

[0030] During the processing of wafer 1, wafer 1 continuously rotates horizontally along its center. The controller sends a movement signal to the first moving arm 61, causing it to move the first nozzle 4 above wafer 1. The controller also sends a start signal to the first nozzle 4, causing it to spray a first liquid towards the center of the wafer. In one embodiment, when the first nozzle 4 has sprayed the first liquid for a set time, the controller sends a movement signal to the second moving arm 62, causing it to move the second nozzle 5. The controller sends a spraying signal to the second nozzle 5, causing it to spray a second liquid onto the wafer surface. The point of contact of the second liquid falls between the first position and the wafer center. Since the centrifugal force experienced by the second liquid at the first position is less than the force required for the second liquid film to diffuse, when the point of contact of the second liquid falls closer to the wafer center than the first position, a liquid film can be formed on the rotating wafer 1 and diffuse towards the wafer center.

[0031] The wafer processing apparatus also includes a vision recognition device for identifying the position of the liquid film. The vision recognition device is electrically connected to a controller, which acquires the liquid film position. When the controller confirms that the liquid film of the second liquid has reached the wafer center, the controller sends a stop signal to the first nozzle 4 to stop spraying the first liquid onto the wafer 1, and sends a movement signal to the first moving arm 61 to move the first nozzle 4 away from the wafer center. In another embodiment, the controller sends a stop signal to the first nozzle 4 after the liquid film of the second liquid has reached the wafer center for a certain period of time.

[0032] The wafer processing equipment also includes a housing, and a chuck 2, a first nozzle 4, and a second nozzle 5 are disposed inside the housing. The first position is located between the center of the wafer and the edge of the wafer, and is a position determined with reference to the housing. Therefore, the positional relationship between the first position and the second nozzle 5 does not change as the wafer 1 rotates.

[0033] During the diffusion of the second liquid film from the second liquid contact point to the wafer center, in order to make the second liquid film diffuse more easily to the wafer center, the controller adjusts the rotation speed of the chuck 2 through the drive component 3. The controller reduces the centrifugal force acting on the second liquid by reducing the rotation speed of the chuck 2, which is beneficial to the diffusion of the second liquid film to the wafer center.

[0034] In another embodiment, as shown in FIG2, in order to accelerate the diffusion of the liquid film formed by the second nozzle 5 towards the wafer center, the second nozzle 5 is an adjustable-angle nozzle. Before the liquid film of the second liquid reaches the wafer center, the contact point of the second liquid is closer to the wafer center than the orthogonal projection of the second nozzle 5 on the wafer. Compared to the contact point of the second liquid falling within the orthogonal projection of the second nozzle 5, this increases the force for the second liquid film to diffuse towards the wafer center, thereby accelerating the diffusion of the second liquid film to the wafer center.

[0035] In the embodiments of this application, when the processing liquid used to process wafer 1 is changed from the first liquid to the second liquid, the first nozzle 4 stops spraying the first liquid onto the center of the wafer only after the liquid film of the second liquid reaches the center of the wafer, so that wafer 1 is covered by the liquid film throughout the entire processing process, which can avoid the appearance of areas on wafer 1 that are not covered by the liquid film due to the lack of connection between the first liquid film and the second liquid film.

[0036] The types of the first and second liquids are determined based on process requirements. If the first liquid is an acid, the second liquid is a cleaning solution. For example, the first liquid could be hydrofluoric acid, and the second liquid could be a mixture of hot ammonia, hydrogen peroxide, and water (Hot SC1). If the first liquid is a cleaning solution, the second liquid can be either a cleaning solution or an acid. For example, the first liquid could be a mixture of hot ammonia, hydrogen peroxide, and water (Hot SC1), and the second liquid could be deionized water with carbon dioxide (DICO2).

[0037] As shown in Figure 3, this embodiment also provides a wafer processing method, which specifically includes the following steps:

[0038] S110: Keep the wafer rotating horizontally around the center of the wafer.

[0039] S120: A first liquid is sprayed onto the wafer surface through a first nozzle, and the liquid landing point of the first liquid falls on the center of the wafer.

[0040] In step S120, a first liquid forms a liquid film on the rotating wafer, and the liquid film diffuses from the center of the wafer to the entire wafer, so that the first liquid processes the wafer. The execution time of step S120 is set according to process requirements.

[0041] S130: Continue spraying the first liquid, and spray the second liquid onto the wafer surface through the second nozzle. The contact point of the second liquid falls between the first position and the center of the wafer. The centrifugal force on the second liquid at the first position is less than the force of the second liquid film diffusion.

[0042] In step S130, the relationship between the centrifugal force on the second liquid at a certain position and the force of the second liquid film diffusion can be determined experimentally. That is, if the second liquid flows entirely from the contact point to the wafer edge at a certain position, the centrifugal force at that position is greater than the force of the second liquid film diffusion; if the second liquid flows from the contact point to the wafer center at a certain position, it indicates that the centrifugal force at that position is less than the force of the second liquid film diffusion. Under the conditions of wafer rotation speed, second liquid type, and second liquid flow rate in step S130, the second nozzle is moved along the wafer radius and the second liquid is sprayed. The critical position where the centrifugal force is less than the force of the second liquid film diffusion is determined. A first position is determined within the range where the distance from the wafer center is less than or equal to the critical distance, so that the centrifugal force on the second liquid at the first position is less than the force of the second liquid film diffusion.

[0043] In step S130, when the contact point of the second liquid falls at the first position, the centrifugal force experienced by the second liquid at the first position is less than the force required for the second liquid film to diffuse, allowing the second liquid film to diffuse towards the wafer center. When the contact point of the second liquid falls at a position closer to the wafer center than the first position, the centrifugal force experienced by the second liquid is even smaller, allowing the second liquid film to diffuse towards the wafer center more quickly. In step S130, the contact points of the first and second liquids can simultaneously fall at the wafer center, enabling the second liquid to diffuse outward from the wafer center and achieving better film bonding.

[0044] To avoid interference between the first and second nozzles, in step S130, the contact point of the second liquid falls between the first and second positions. The second position is located between the first position and the wafer center, and the distance between the second position and the wafer center is greater than or equal to the sum of the radii of the first and second liquid contact points. The radius of the first liquid contact point refers to the radius of the wafer area covered by the first liquid when it lands on the wafer and has not yet diffused. The radius of the second liquid contact point refers to the radius of the wafer area covered by the second liquid when it lands on the wafer and has not yet diffused. When the contact point of the second liquid falls at the second position, the contact point of the first liquid can simultaneously fall at the wafer center, and the contact point of the second liquid will not interfere with the spraying of the first liquid. Therefore, having the contact point of the second liquid between the first and second positions ensures that the second liquid film diffuses towards the wafer center while preventing the second liquid from interfering with the first nozzle's spraying of the first liquid. The second position is determined with reference to the outer casing and does not change with wafer rotation.

[0045] In step S130, before the second liquid reaches the wafer center, the second nozzle does not move when spraying the second liquid, meaning the distance between the contact point of the second liquid and the wafer center remains constant. During wafer rotation, as the liquid film of the second liquid diffuses towards the wafer center, it also diffuses towards the wafer edge under centrifugal force. Since it takes time for the liquid film to diffuse from the contact point to the wafer center, the liquid film diffusing from the contact point to the wafer edge can simultaneously cover areas on the wafer farther from the wafer center than the contact point, which is beneficial for subsequent liquid film bonding.

[0046] In another specific embodiment, in order to accelerate the diffusion of the second liquid to the wafer center, in step S130, if the contact point of the second liquid is not at the second position when the second nozzle sprays the second liquid, the second nozzle is moved during the spraying process to move the contact point of the second liquid to the second position, thereby reducing the distance between the contact point of the second liquid and the wafer center, thereby reducing the centrifugal force on the second liquid and shortening the diffusion distance of the second liquid film, thus accelerating the diffusion of the second liquid to the wafer center.

[0047] In step S130, when the second liquid nozzle begins spraying the second liquid, the contact point of the second liquid falls between the first and second positions, which facilitates the diffusion of the second liquid film towards the wafer center. In another specific embodiment, if the contact point of the second liquid does not fall between the first and second positions when the second liquid nozzle begins spraying the second liquid, the contact point of the second liquid is moved to between the first and second positions before the nozzle sprays the second liquid, or the contact point of the second liquid is moved to between the first and second positions while the nozzle is spraying the second liquid.

[0048] S140: When the liquid film of the second liquid reaches the center of the wafer, stop spraying the first liquid and remove the first nozzle, continue spraying the second liquid and move the second nozzle to move the contact point of the second liquid to the center of the wafer and keep the second nozzle spraying the second liquid.

[0049] In step S140, the movement trajectory of the first nozzle does not intersect with that of the second nozzle to avoid collisions. Preferably, the movement direction of the first nozzle is the same as that of the second nozzle. In another specific embodiment, the spraying of the first liquid can be stopped and the first nozzle removed after the liquid film of the second liquid has reached the center of the wafer for a certain period of time.

[0050] In order to make it easier for the liquid film of the second liquid to diffuse to the center of the wafer, in step S120 or step S130, the wafer rotation speed is reduced so that the liquid film of the second liquid is subjected to less centrifugal force during the diffusion process towards the center of the wafer, thereby making it easier for the liquid film of the second liquid to diffuse to the center of the wafer.

[0051] In order to accelerate the diffusion of the second liquid film towards the center, the flow rate of the second liquid in step S130 is greater than that in step S140, so as to increase the gravity of the second liquid, thereby increasing the force of the second liquid film diffusion, so that the second liquid film can quickly diffuse to the center of the wafer.

[0052] To further accelerate the diffusion of the second liquid film toward the center, in step S130, the contact point of the second liquid is closer to the center of the wafer than the orthogonal projection of the nozzle on the wafer, so as to increase the force of the second liquid film diffusing toward the center of the wafer, which is more conducive to the diffusion of the second liquid film to the center of the wafer.

[0053] Steps S110 to S140 can be executed by the controller in the wafer processing apparatus described above.

[0054] In the wafer processing method shown in Figure 3, after the first liquid spraying stops, the first liquid diffuses outward under the action of centrifugal force. The center of the wafer lacks the coverage of the first liquid, but at this time, the liquid film of the second liquid has already reached the center of the wafer. Therefore, the liquid films of the first and second liquids will connect at the center of the wafer, and the liquid film at the center of the wafer will not break. As the first liquid continues to diffuse outward under the action of centrifugal force, the liquid film of the second liquid also continues to diffuse outward, thus ensuring that the liquid film on the wafer remains connected, gradually replacing the processing liquid on the entire wafer surface with the second liquid, while the liquid film on the wafer surface never breaks. Moreover, since the first liquid spraying stops just as the second liquid film reaches the center of the wafer, the supply time of the first liquid can be shortened as much as possible to save the amount of first liquid used.

[0055] Other embodiments of this application will readily occur to those skilled in the art upon consideration of the specification and practice of the embodiments disclosed herein. This application is intended to cover any variations, uses, or adaptations of this application that follow the general principles of this application and include common knowledge or customary techniques in the art not disclosed herein.

[0056] It should be understood that this application is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this application is limited only by the appended claims.

Claims

1. A wafer processing method, characterized in that, include: Rotating wafer; A first liquid is sprayed onto the center of the wafer for a predetermined time through a first nozzle; Continue spraying the first liquid, and spray the second liquid onto the wafer surface through the second nozzle. The contact point of the second liquid falls between the first position and the center of the wafer. The centrifugal force on the second liquid at the first position is less than the force that the second liquid diffuses outward from the contact point. After the second liquid reaches the center of the wafer, the spraying of the first liquid onto the center of the wafer is stopped.

2. The wafer processing method according to claim 1, characterized in that, It also includes a second position between the first position and the wafer center, wherein the contact point of the second liquid falls between the first position and the second position, and the distance between the second position and the wafer center is greater than or equal to the sum of the radius of the first liquid contact point and the radius of the second liquid contact point.

3. The wafer processing method according to claim 2, characterized in that, The second nozzle does not move until the second liquid reaches the center of the wafer.

4. The wafer processing method according to claim 2, characterized in that, Before the second liquid reaches the center of the wafer, the second nozzle is moved to move the point of contact of the second liquid toward the second position.

5. The wafer processing method according to claim 1, characterized in that, Before the liquid film of the second liquid reaches the center of the wafer, the wafer rotates at a first speed, and after the liquid film of the second liquid reaches the center of the wafer, the wafer rotates at a second speed, wherein the first speed is less than the second speed.

6. The wafer processing method according to claim 1, characterized in that, Before the liquid film of the second liquid reaches the center of the wafer, the second liquid is sprayed at a first flow rate, and after the liquid film of the second liquid reaches the center of the wafer, the second liquid is sprayed at a second flow rate, wherein the first flow rate is greater than the second flow rate.

7. The wafer processing method according to claim 1, characterized in that, Before the liquid film of the second liquid reaches the center of the wafer, the point of contact of the second liquid is closer to the center of the wafer than the orthogonal projection of the second nozzle on the wafer.

8. The wafer processing method according to claim 1, characterized in that, After stopping the spraying of the first liquid towards the center of the wafer, the second liquid is sprayed and the second nozzle is moved to move the contact point of the second liquid to the center of the wafer.

9. A wafer processing apparatus, characterized in that, include: Rotation unit, used to rotate the wafer; The first nozzle is used to spray the first liquid; The second nozzle is used to spray the second liquid; The controller is configured to spray a first liquid onto the wafer center through the first nozzle and a second liquid onto the wafer surface through the second nozzle, wherein the contact point of the second liquid falls between the first position and the wafer center, and the centrifugal force experienced by the second liquid at the first position is less than the force by which the second liquid diffuses outward from the contact point; After the liquid film of the second liquid reaches the center of the wafer, the spraying of the first liquid onto the center of the wafer is stopped.

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