Control system for bubbles in liquid film, and wafer cleaning device and wafer cleaning method

Abstract

The present application relates to a control system for bubbles in a liquid film, and a wafer cleaning device and a wafer cleaning method. The control system for bubbles in a liquid film comprises a megasonic generator, a sampler, a bubble detection module and a controller, wherein the megasonic generator is used for transmitting acoustic energy to a liquid film on a wafer, so as to clean the wafer; the sampler is used for acquiring a liquid in the liquid film on the wafer during a process in which the megasonic generator cleans the wafer; the bubble detection module is connected to the sampler, and is used for performing bubble detection on the liquid acquired in the sampler and determining bubble parameters in the liquid; and the controller is connected to the bubble detection module, and is used for adjusting operation parameters of the megasonic generator on the basis of the bubble parameters, so that the bubble parameters are within a preset range. The present application solves the problem in the prior art of the "cavitation effect" of bubbles caused by the expansion, contraction and oscillation of the bubbles leading to the collapse of and damage to a pattern structure on a wafer, thereby improving the wafer production yield.

Description

Control system for bubbles in liquid film, wafer cleaning equipment and wafer cleaning method Technical Field

[0001] The present application relates to the field of integrated circuit manufacturing, and in particular to a control system for bubbles in a liquid film, a wafer cleaning device, and a wafer cleaning method. Background Art

[0002] The rapid development of the integrated circuit industry has placed ever-higher demands on the speed and performance of integrated circuits. Currently, integrated circuit chip features are being designed to be smaller and smaller, with ever-increasing aspect ratios. Simultaneously, the challenges faced in various processes are becoming increasingly severe. According to statistics, over half of yield loss in semiconductor manufacturing is due to micro-contamination. Therefore, wafer cleaning is a critical step in integrated circuit manufacturing. As wafer feature sizes continue to shrink, not only does the number of cleaning steps increase, but also stricter requirements are placed on the tolerable size and number of particles on the wafer surface.

[0003] To address these issues, ultrasonic or megasonic cleaning technologies have emerged. Ultrasonic or megasonic equipment generates bubble cavitation oscillations during the wafer cleaning process, effectively removing tiny impurity particles. Currently, the use of megasonic energy to remove particles and other contaminants during wafer cleaning is widely used. Megasonic waves generate bubbles during wafer cleaning, and the stretching and contracting vibrations of the bubbles help to remove particles from the wafer surface to a certain extent. However, these stretching and contracting vibrations can also cause a "cavitation effect" within the bubbles, leading to the collapse and damage of graphic structures on the wafer during the process. Furthermore, as the feature size on the wafer decreases, the impact of the "cavitation effect" becomes greater.

[0004] Summary of the Invention

[0005] The embodiments of the present application provide a control system for bubbles in a liquid film, a wafer cleaning device, and a wafer cleaning method, so as to at least solve the problem in the prior art of the "cavitation effect" of bubbles caused by the expansion and contraction vibration of bubbles, thereby causing the collapse and damage of the graphic structure on the wafer during the process.

[0006] In a first aspect, an embodiment of the present application provides a control system for controlling bubbles in a liquid film on a wafer when a megasonic wave generator is used to clean the wafer, comprising:

[0007] a megasonic wave generator for transmitting acoustic energy to the liquid film on the wafer to clean the wafer;

[0008] a sampler for obtaining liquid from a liquid film on a wafer during cleaning of the wafer by the megasonic generator;

[0009] a bubble detection module, connected to the sampler, for performing bubble detection on the liquid obtained from the sampler and determining bubble parameters in the liquid;

[0010] A controller is connected to the bubble detection module and is used to adjust the operating parameters of the megasonic generator according to the bubble parameters so that the bubble parameters are within a preset range.

[0011] In some embodiments, a mounting assembly is further included, which includes: a mounting plate and at least one fixing member, the mounting plate is connected to the megasonic generator, the fixing member is fixed to the mounting plate, and the fixing member is used to fix the sampler.

[0012] In some embodiments, a plurality of first fixing holes are provided on the mounting plate, and a protrusion that matches with the first fixing holes is provided on the fixing member, and the protrusion matches with the first fixing holes to fix the fixing member.

[0013] In some embodiments, at least one second fixing hole is provided on the fixing member, and the sampler is installed in the second fixing hole and is used to obtain liquid in the liquid film during wafer cleaning.

[0014] In some embodiments, a liquid pump is further included, which is disposed between the bubble detection module and the sampler and is used to provide power to the sampler for obtaining liquid in the liquid film during wafer cleaning.

[0015] In some embodiments, the bubble parameters include bubble size and / or bubble concentration.

[0016] In some embodiments, the operating parameters of the megasonic wave generator include power, power-on duty cycle, and pulse period.

[0017] In a second aspect, an embodiment of the present application further provides a wafer cleaning device, comprising a control system as described in the first aspect.

[0018] In a third aspect, an embodiment of the present application further provides a wafer cleaning method, comprising:

[0019] applying a cleaning liquid to the wafer and forming a liquid film on the wafer;

[0020] using a megasonic wave generator to transmit acoustic energy to the liquid film on the wafer to clean the wafer;

[0021] obtaining liquid in a liquid film on a wafer during wafer cleaning by a megasonic wave generator;

[0022] Performing bubble detection on the obtained liquid to determine bubble parameters in the liquid;

[0023] The operating parameters of the megasonic generator are adjusted according to the bubble parameters so that the bubble parameters are within a preset range.

[0024] In summary, the control system for bubbles in the liquid film, wafer cleaning equipment and wafer cleaning method provided in the embodiments of the present application apply cleaning liquid to the wafer and form a liquid film on the wafer; use a megasonic generator to transmit acoustic energy to the liquid film on the wafer to clean the wafer; obtain the liquid in the liquid film on the wafer during the wafer cleaning by the megasonic generator; perform bubble detection on the obtained liquid to determine the bubble parameters in the liquid; adjust the operating parameters of the megasonic generator according to the bubble parameters so that the bubble parameters are within a preset range, thereby realizing the control and adjustment of the bubble parameters, solving the problem in the prior art of the "cavitation effect" of bubbles caused by the expansion and contraction vibration of bubbles, which leads to the collapse and damage of the graphic structure on the wafer during the process, and improving the wafer production yield.

[0025] The details of one or more embodiments of the present application are set forth in the following drawings and description to make other features, objects, and advantages of the present application more readily apparent.

[0026] Summary of the Figures

[0027] The features and performance of the present application are further described by the following examples and drawings.

[0028] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0029] FIG1 is a schematic structural diagram of a control system for bubbles in a liquid film according to an embodiment of the present application;

[0030] FIG2 is a schematic structural diagram of a control system for bubbles in a liquid film according to another embodiment of the present application;

[0031] FIG3 is a partial structural diagram of a control system for bubbles in a liquid film according to an embodiment of the present application;

[0032] FIG4 is a schematic structural diagram of a wafer cleaning device according to an embodiment of the present application;

[0033] FIG5 is a flow chart of a wafer cleaning method according to an embodiment of the present application.

[0034] Preferred embodiment of this application

[0035] In order to make the purpose, technical solutions and advantages of the present application clearer, the present application is described and illustrated below in conjunction with the accompanying drawings and examples. It should be understood that the specific embodiments described herein are only used to explain the present application and are not intended to limit the present application. Based on the embodiments provided in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present application. In addition, it can also be understood that although the efforts made in this development process may be complex and lengthy, for ordinary technicians in the field related to the contents disclosed in the present application, some changes such as design, manufacturing or production based on the technical contents disclosed in the present application are only conventional technical means and should not be understood as the contents disclosed in the present application being insufficient.

[0036] Unless otherwise defined, the technical or scientific terms used in this application should have the ordinary meaning understood by a person of ordinary skill in the technical field to which this application belongs. The words "one", "a", "the" and the like used in this application do not indicate a limit on quantity and may indicate the singular or plural. The terms "include", "comprise", "have" and any variations thereof used in this application are intended to cover non-exclusive inclusions; for example, a process, method, system, product or device that includes a series of steps or modules (units) is not limited to the listed steps or units, but may also include steps or units that are not listed, or may also include other steps or units that are inherent to these processes, methods, products or devices. The words "connect", "connected", "coupled" and the like used in this application are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. The word "multiple" used in this application means greater than or equal to two. "And / or" describes the association relationship of associated objects, indicating that three relationships can exist. For example, "A and / or B" can mean: A exists alone, A and B exist at the same time, and B exists alone. The terms "first", "second", "third" and the like involved in this application are merely used to distinguish similar objects and do not represent a specific ordering of the objects.

[0037] Please refer to Figure 1. The embodiment of the present application proposes a control system for bubbles in liquid film, which can be applied to wafer cleaning equipment, and its structure will be described later. Figure 4 shows a wafer cleaning equipment including a control system for bubbles in liquid film. As shown in Figure 4, the wafer cleaning equipment includes a control system 4 for bubbles in liquid film, a robotic arm 2, a wafer carrying and rotating assembly 1, a nozzle 7 and a cavity 10. The control system 4 for bubbles in liquid film includes a megasonic generator 43, which is arranged on the robotic arm 2. The control system 4 for bubbles in liquid film is used to detect the bubble parameters in the liquid film 5 on the surface of the wafer 6 during the wafer cleaning by the megasonic generator 43, and adjust the operating parameters of the megasonic generator 43 according to the bubble parameters, so that the bubble parameters in the liquid film 5 are within a preset range. The wafer carrying and rotating assembly 1 is arranged inside the cavity 10, and is used to carry the wafer 6 and drive the wafer 6 to rotate.

[0038] It should be noted that the liquid film 5 is formed by spraying the cleaning liquid onto the wafer 6 through the nozzle 7 during the cleaning of the wafer 6 .

[0039] When using the wafer cleaning equipment of the present application to clean wafer 6, the wafer carrying rotating assembly 1 holds wafer 6 and drives wafer 6 to rotate at a set speed, and the nozzle 7 sprays cleaning liquid onto wafer 6 to form a liquid film 5 on wafer 6. Driven by a driving device (not shown), the robotic arm 2 drives the megasonic generator 43 to rotate above the wafer 6 and transmits acoustic energy to the wafer 6 through the liquid film 5 to clean the wafer 6. The control system 4 of the bubbles in the liquid film detects in real time the bubble parameters in the liquid film 5 on the surface of the wafer 6 during the cleaning of the wafer 6 by the megasonic generator 43, and adjusts the operating parameters of the megasonic generator 43 according to the bubble parameters so that the bubble parameters in the liquid film 5 are within a preset range.

[0040] The present application sets a control system 4 for bubbles in the liquid film to detect in real time the bubble parameters in the liquid film 5 on the wafer 6 during the cleaning period, and adjusts the operating parameters of the megasonic generator 43 according to the bubble parameters so that the bubble parameters in the liquid film 5 are within a preset range, thereby achieving the adjustment of the bubble parameters in the liquid film 5 and preventing the bubbles from being too large and causing a "cavitation effect", solving the problem in the prior art of the "cavitation effect" of bubbles caused by the expansion and contraction vibration of bubbles, which leads to the collapse and damage of the graphic structure on the wafer, thereby improving the wafer production yield.

[0041] It should be noted that the bubble "cavitation effect" refers to the dynamic process of growth and collapse of micro-cavitation bubbles with air cores existing in liquids that vibrate under the action of sound waves and occur when the sound pressure reaches a certain value.

[0042] The bubble parameters in the embodiment of the present application may be bubble size and / or bubble concentration. In this embodiment, when the bubble size remains unchanged, the higher the bubble concentration, the greater the probability that the bubble will experience cavitation effect; when the bubble concentration remains unchanged, the larger the bubble size, the greater the probability that the bubble will experience cavitation effect. Therefore, in the present application, by detecting the bubble size and / or bubble concentration, and adjusting the operating parameters of the megasonic generator 43 according to the detected bubble size and / or bubble concentration, so that the bubble size and / or bubble concentration are both within a preset range, the "cavitation effect" of the bubbles is avoided, so as to solve the problem in the prior art that the "cavitation effect" of the bubbles is caused by the expansion and contraction vibration of the bubbles, thereby causing damage to the graphic structure on the wafer, thereby improving the wafer production yield.

[0043] It should be noted that in the embodiment of the present application, corresponding preset ranges are set for both bubble size and bubble concentration.

[0044] The operating parameters of the megasonic generator 43 in the embodiment of the present application may include, but are not limited to, the power, power-on duty cycle, and pulse period of the megasonic generator 43. For example, when it is detected that the bubble size or bubble concentration exceeds a preset range, the bubble size or bubble concentration may be brought within the preset range by reducing the power of the megasonic generator 43, increasing the duty cycle, or reducing the pulse period.

[0045] In some embodiments, the megasonic generator 43 can be mounted on the robotic arm 2 via a mounting bracket (not shown), and other components of the control system for bubbles in liquid films 4 can also be mounted on the mounting bracket, so that the robotic arm 2 can simultaneously control the bottom of the sampler 42 in the control system for bubbles in liquid films 4 to be at the same level as the bottom of the megasonic generator 43, thereby facilitating the sampler 42 to obtain liquid in the liquid film 5. In these embodiments, since the other components of the control system for bubbles in liquid films 4 and the megasonic generator 43 are both mounted on the robotic arm 2, the other components of the control system for bubbles in liquid films 4 and the megasonic generator 43 may not have a direct connection relationship and may or may not be in contact with each other.

[0046] It should be noted that the mounting bracket in this embodiment is not equivalent to the mounting component 41. The mounting bracket is used to fix the megasonic generator 43 on the robotic arm 2, and the mounting component 41 is used to install the sampler 42 in the control system 4 for bubbles in the liquid film. For example, the sampler 42 can be installed on the mounting bracket through the mounting component 41.

[0047] Continuing to refer to Figure 1, an embodiment of the present application provides a control system 4 for controlling bubbles in the liquid film on the wafer when the megasonic generator cleans the wafer. The control system 4 for bubbles in the liquid film includes a megasonic generator 43, a sampler 42, a bubble detection module 44, and a controller 45. The sampler 42 is used to obtain the liquid in the liquid film 5 on the wafer 6 while the megasonic generator 43 cleans the wafer 6. The bubble detection module 44 is connected to the sampler 42 and is used to perform bubble detection on the liquid obtained from the sampler 42 and determine the bubble parameters in the liquid. The controller 45 is electrically connected to the bubble detection module 44 and is communicatively connected to the megasonic generator 43 for adjusting the operating parameters of the megasonic generator 43 according to the bubble parameters so that the bubble parameters are within a preset range.

[0048] According to this embodiment, the liquid in the liquid film 5 on the wafer 6 during the cleaning of the wafer 6 can be obtained in real time through the sampler 42 and the liquid can be transported to the bubble detection module 44. The bubble detection module 44 performs bubble parameter detection on the liquid obtained in the sampler 42 and sends the bubble parameter detection result to the controller 45. Finally, the controller 45 adjusts the operating parameters of the megasonic generator 43 according to the obtained bubble parameters to make the bubble parameters within the preset range, thereby realizing the adjustment of the bubble parameters, avoiding the bubble size in the liquid film 5 being too large or the bubble concentration being too high, resulting in the "cavitation effect" of the bubbles during the bubble expansion and contraction vibration, causing damage to the graphic structure on the wafer, and improving the wafer production yield.

[0049] In the embodiments of the present application, the bubble detection module 44 may be, but is not limited to, an NTA nanoparticle tracking instrument, which can monitor bubble parameters and analyze bubble parameters in a sample in real time. The controller 45, which may include, but is not limited to, a receiver and a computer, can receive and analyze the bubble parameters transmitted by the bubble detection module 44 in real time. When the bubble parameters reach a set warning value for the occurrence of a "cavitation effect," the controller automatically adjusts the operating parameters of the megasonic generator 43 to adjust the bubble size and / or concentration to within a preset range, thereby preventing the occurrence of a "cavitation effect."

[0050] It should be noted that the warning value can be determined by the bubble parameters when the bubbles in the liquid film in the current process flow undergo cavitation effect. Secondly, the preset range in the above embodiment can be adjusted according to different wafer cleaning processes and is not specifically limited here.

[0051] 2 , in some embodiments, the control system 4 for controlling bubbles in the liquid film further includes a liquid pump 46, which is disposed between the bubble detection module 44 and the sampler 42 and is configured to provide power to the sampler 42 for obtaining liquid from the liquid film 5 during the cleaning of the wafer 6. The liquid pump 46 obtains liquid from the liquid film 5 during the cleaning of the wafer 6 through the sampler 42 and delivers the liquid to the bubble detection module 44. The provision of the liquid pump 46 facilitates obtaining liquid from the liquid film 5 on the wafer 6.

[0052] Referring to Figure 3, a front view of the sampler 42 and mounting assembly 41 is shown. In some embodiments, the control system for bubbles in liquid films 4 further includes a mounting assembly 41, which comprises a mounting plate 411 and at least one fixing member 412. The mounting plate 411 is connected to the megasonic generator 43 and is fixed to the robotic arm 2. The fixing member 412 is fixed to the mounting plate 411 and is used to secure the sampler 42.

[0053] In this embodiment, the mounting plate 411 and the megasonic generator 43 can be detachably connected to facilitate replacement of the mounting plate 411, thereby avoiding the problem of complicated replacement due to damage of the mounting plate 411 after long-term use. In addition, a plurality of fixing members 412 can be provided on the mounting plate 411 to enable installation and fixation of a plurality of samplers 42. By installing a plurality of samplers 42, it is possible to sample the liquid at different positions in the liquid film on the wafer 6 to ensure the accuracy of the sampling results. In this embodiment, the sampler 42 and the megasonic generator 43 are both connected to the mounting plate 411 to facilitate control of the bottom of the sampler 42 and the bottom of the megasonic generator 43 at the same horizontal height, so that when the megasonic generator 43 is working, the sampler 42 can obtain the liquid in the liquid film 5.

[0054] 3 , in some embodiments, the mounting plate 411 is provided with a plurality of first fixing holes 413, and the fixing member 412 is provided with protrusions (not shown) that cooperate with the first fixing holes 413. The protrusions cooperate with the first fixing holes 413 to fix the fixing member 412. For example, the protrusions can be cylinders that fit into the first fixing holes 413. Referring to FIG3 , the protrusions are inserted into the first fixing holes 413 in a direction inward from the drawing.

[0055] It should be noted that the fixing member may be fixed to the mounting plate by other existing technologies capable of achieving fixation, such as welding, bonding, etc.

[0056] In some embodiments, the fixing member 412 is provided with at least one second fixing hole (not shown), the second fixing hole being provided through the upper and lower surfaces of the fixing member 412, and the sampler 42 being installed in the second fixing hole and passing through the lower surface of the second fixing hole to obtain the liquid in the liquid film during wafer cleaning. As shown in FIG3 , the second fixing hole can pass through the fixing member 412 along the direction D shown in FIG3 . The control system 4 for bubbles in the liquid film can also include a position fixing member, and when the height of the sampler 42 is adjusted so that its lower surface is located in the liquid film 5, the position fixing member is used to fix the height of the sampler 42. According to the thickness of the liquid film 5, the height of the sampler 42 can be adjusted to make it suitable for liquid films 5 of different thicknesses. It should be noted that the end of the sampler 42 extending into the liquid film 5 should not contact the wafer surface.

[0057] The present application also provides a wafer cleaning method, which can be applied to the wafer cleaning device shown in FIG4 . As shown in FIG5 , the wafer cleaning method includes the following steps:

[0058] Step S501, applying a cleaning liquid to the wafer and forming a liquid film on the wafer;

[0059] Step S502 , using a megasonic generator to transmit acoustic energy to the liquid film on the wafer to clean the wafer;

[0060] Step S503, obtaining liquid in the liquid film on the wafer during the wafer cleaning process using the megasonic generator;

[0061] Step S504, performing bubble detection on the acquired liquid to determine bubble parameters in the liquid;

[0062] Step S505 , adjusting the operating parameters of the megasonic generator according to the bubble parameters so that the bubble parameters are within a preset range.

[0063] In an embodiment of the present application, bubble detection is performed on the obtained liquid to determine the bubble parameters in the liquid, and the operating parameters of the megasonic wave generator are adjusted according to the bubble parameters, so that the bubble parameters are within a preset range. This achieves the adjustment of the bubble parameters, prevents the bubbles from being too large in size or too high in concentration, and causes a "cavitation effect" of the bubbles. This solves the problem in the prior art of the "cavitation effect" of the bubbles caused by the expansion and contraction vibration of the bubbles, which leads to the collapse and damage of the graphic structure on the wafer, thereby improving the wafer production yield.

[0064] Those skilled in the art should understand that the various technical features of the above-described embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the various technical features in the above-described 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.

[0065] 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 skilled in the art could make various modifications and improvements without departing from the spirit of the present application, all of which fall within the scope of protection of the present application. Therefore, the scope of protection of the present patent application shall be determined by the appended claims.

Claims

1. A control system for controlling bubbles in a liquid film on a wafer when a megasonic generator is used to clean the wafer, characterized in that: include: a megasonic generator for transmitting acoustic energy to a liquid film on a wafer to clean the wafer; A sampler, used for obtaining liquid in a liquid film on a wafer during the wafer cleaning process by the megasonic generator; A bubble detection module, connected to the sampler, for performing bubble detection on the liquid obtained from the sampler to determine bubble parameters in the liquid; A controller is connected to the bubble detection module and is used to adjust the operating parameters of the megasonic generator according to the bubble parameters so that the bubble parameters are within a preset range.

2. The control system according to claim 1, characterized in that: It further comprises a mounting assembly, which comprises: a mounting plate and at least one fixing member, wherein the mounting plate is connected to the megasonic generator, the fixing member is fixed to the mounting plate, and the fixing member is used to fix the sampler.

3. The control system according to claim 2, characterized in that: The mounting plate is provided with a plurality of first fixing holes, the fixing member is provided with protrusions matched with the first fixing holes, and the protrusions match with the first fixing holes to fix the fixing member.

4. The control system according to claim 3, characterized in that: The fixing member is provided with at least one second fixing hole, and the sampler is installed in the second fixing hole.

5. The control system according to claim 1, characterized in that: It further includes a liquid pump, which is arranged between the bubble detection module and the sampler and is used to provide power to the sampler for obtaining liquid in the liquid film during wafer cleaning.

6. The control system according to claim 1, characterized in that: The bubble parameters include bubble size and / or bubble concentration.

7. The control system according to claim 1, characterized in that: The operating parameters of the megasonic generator include power, power-on duty cycle and pulse period.

8. A wafer cleaning device, characterized in that: Comprising a control system as claimed in any one of claims 1 to 7.

9. A wafer cleaning method, characterized in that: include: applying a cleaning liquid to the wafer and forming a liquid film on the wafer; Using a megasonic generator to transmit acoustic energy to the liquid film on the wafer to clean the wafer; Acquiring liquid in a liquid film on a wafer during wafer cleaning by a megasonic generator; Performing bubble detection on the acquired liquid to determine bubble parameters in the liquid; The operating parameters of the megasonic generator are adjusted according to the bubble parameters so that the bubble parameters are within a preset range.

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