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

Abstract

The invention relates to a control system for bubbles in a liquid film, wafer cleaning equipment and a wafer cleaning method. The control system for the bubbles in the liquid film comprises a megasonic generator, a sampler, a bubble detection module and a controller. The megasonic generator is used for transmitting sound energy to the liquid film on the wafer so as to clean the wafer. The sampler is used for obtaining liquid in a liquid film on the wafer when the wafer is cleaned by the megasonic generator. The bubble detection module is connected with the sampler and used for conducting bubble detection on the liquid obtained in the sampler and determining bubble parameters in the liquid. The controller is connected with the bubble detection module and used for adjusting operation parameters of the megasonic generator according to the bubble parameters so that the bubble parameters can be within a preset range. According to the invention, the problem that the pattern structure on the wafer collapses and is damaged due to the cavitation effect of the bubbles caused by the telescopic vibration of the bubbles in the prior art is solved, and the production yield of the wafer is improved.

Description

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] With the rapid development of the integrated circuit industry, higher requirements are placed on the operating speed and performance of integrated circuits. At present, the feature size of integrated circuit chips is designed to be smaller and smaller, and the aspect ratio is getting larger and larger. At the same time, the challenges faced in many processes are becoming more and more severe. According to statistics, more than half of the yield loss in semiconductor manufacturing is caused by micro-contamination. Therefore, wafer cleaning is a key step in integrated circuit manufacturing. As the feature size on the wafer continues to shrink, not only the number of cleaning steps is increasing, but also more stringent requirements are placed on the tolerable size and number of particles on the wafer surface.

[0003] In order to solve such problems, ultrasonic or megasonic cleaning technology came into being. Ultrasonic or megasonic equipment generates bubble cavitation oscillations during the wafer cleaning process, which can effectively remove fine impurity particles. At present, the use of megasonic energy to remove particles and other contaminants during wafer cleaning has been widely used. Megasonic waves will generate bubbles during the wafer cleaning process, and the stretching and vibration of the bubbles can help to remove particles on the wafer surface to a certain extent. However, the stretching and vibration of the bubbles may also cause the "cavitation effect" of the bubbles, resulting in the collapse and damage of the graphic structure on the wafer during the process, and as the feature size on the wafer decreases, the impact of the "cavitation effect" will be greater. Summary of the invention

[0004] 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 that the "cavitation effect" of bubbles is 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.

[0005] 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 generator cleans the wafer, comprising:

[0006] a megasonic generator for transmitting acoustic energy to a liquid film on a wafer to clean the wafer;

[0007] A sampler, used for obtaining liquid in a liquid film on a wafer during the wafer cleaning process by the megasonic generator;

[0008] 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;

[0009] 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.

[0010] In some of the embodiments, a mounting assembly is further included, and the mounting assembly 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.

[0011] In some embodiments, a plurality of first fixing holes are provided on the mounting plate, and a protrusion matching 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.

[0012] In some of the 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.

[0013] In some of the embodiments, a liquid pump is further included, wherein the liquid pump 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.

[0014] In some of the embodiments, the bubble parameters include: bubble size and / or bubble concentration.

[0015] In some of the embodiments, the operating parameters of the megasonic generator include power, power-on duty cycle and pulse period.

[0016] In a second aspect, an embodiment of the present application also provides a wafer cleaning device, including a control system as described in the first aspect.

[0017] In a third aspect, an embodiment of the present application further provides a wafer cleaning method, comprising:

[0018] applying a cleaning liquid to the wafer and forming a liquid film on the wafer;

[0019] Using a megasonic generator to transmit acoustic energy to the liquid film on the wafer to clean the wafer;

[0020] Acquiring liquid in a liquid film on a wafer during wafer cleaning by a megasonic generator;

[0021] Performing bubble detection on the acquired liquid to determine bubble parameters in the liquid;

[0022] The operating parameters of the megasonic generator are adjusted according to the bubble parameters so that the bubble parameters are within a preset range.

[0023] In summary, the control system of bubbles in the liquid film, wafer cleaning equipment and wafer cleaning method provided in the embodiments of the present application are achieved by applying 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; obtaining liquid in the liquid film on the wafer during the wafer cleaning by the megasonic generator; performing bubble detection on the obtained liquid to determine the bubble parameters in the liquid; and adjusting the operating parameters of the megasonic generator according to the bubble parameters so that the bubble parameters are within a preset range, thereby achieving control and adjustment of the bubble parameters, solving the problem of "cavitation effect" of bubbles caused by the expansion and contraction vibration of bubbles in the prior art, thereby causing the collapse and damage of the graphic structure on the wafer during the process, and improving the wafer production yield.

[0024] 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. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] 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:

[0026] Figure 1 is a schematic structural diagram of a control system for bubbles in a liquid film according to an embodiment of the present application;

[0027] Figure 2 is a structural schematic diagram of a control system for bubbles in a liquid film according to another embodiment of the present application;

[0028] Figure 3 is a partial structural schematic diagram of a control system for bubbles in a liquid film according to an embodiment of the present application;

[0029] Figure 4 is a schematic structural diagram of a wafer cleaning device according to an embodiment of the present application;

[0030] Figure 5 It is a flow chart of a wafer cleaning method according to an embodiment of the present application. DETAILED DESCRIPTION

[0031] 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 embodiments. 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 insufficient contents disclosed in the present application.

[0032] Unless otherwise defined, the technical terms or scientific terms involved in this application should be understood by people with ordinary skills in the technical field to which this application belongs. The words "one", "a", "a", "the" and the like involved in this application do not indicate a quantitative limitation, and may represent the singular or plural. The terms "include", "comprise", "have" and any of their variations involved 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 inherent to these processes, methods, products or devices. The words "connect", "connected", "coupled" and the like involved in this application are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. The "multiple" involved in this application refers to greater than or equal to two. "And / or" describes the association relationship of associated objects, indicating that there can be three relationships, for example, "A and / or B" can represent: 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 the present application are merely used to distinguish similar objects and do not represent a specific ordering of the objects.

[0033] See also Figure 1 , an embodiment of the present application proposes a control system for bubbles in a liquid film, which can be applied to wafer cleaning equipment, and its structure will be described later. Figure 4 FIG. 2 shows a wafer cleaning apparatus including a control system for controlling bubbles in a liquid film. Figure 4As shown, the wafer cleaning equipment includes a control system 4 for bubbles in a liquid film, a robot arm 2, a wafer carrying and rotating assembly 1, a nozzle 7 and a cavity 10. The control system 4 for bubbles in a liquid film includes a megasonic generator 43, which is arranged on the robot arm 2. The control system 4 for bubbles in a liquid film is used to detect the bubble parameters in a liquid film 5 on the surface of a wafer 6 during the wafer cleaning by the megasonic generator 43, and to 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.

[0034] 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 .

[0035] When the wafer cleaning device of the present application is used to clean the wafer 6, the wafer carrying rotating assembly 1 holds the wafer 6 and drives the wafer 6 to rotate at a set rotation speed, the nozzle 7 sprays the cleaning liquid onto the wafer 6 to form a liquid film 5 on the wafer 6, and the robot arm 2, driven by a driving device (not shown), 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.

[0036] 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 the bubbles, which causes the collapse and damage of the graphic structure on the wafer, thereby improving the wafer production yield.

[0037] 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.

[0038] The bubble parameters in the embodiment of the present application may be the bubble size and / or the bubble concentration. In the present 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 within a preset range, the bubble is prevented from experiencing "cavitation effect", so as to solve the problem in the prior art that the "cavitation effect" of the bubble is caused by the expansion and contraction vibration of the bubble, thereby causing damage to the graphic structure on the wafer, thereby improving the wafer production yield.

[0039] It should be noted that in the embodiment of the present application, corresponding preset ranges are set for both the bubble size and the bubble concentration.

[0040] 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 the preset range, the bubble size or bubble concentration may be made within the preset range by reducing the power of the megasonic generator 43, increasing the duty cycle and reducing the pulse period in one or more ways.

[0041] In some embodiments, the megasonic generator 43 can be mounted on the robot 2 through a mounting frame (not shown), and other components of the control system 4 for bubbles in liquid film can also be mounted on the mounting frame, so that the robot 2 can simultaneously control the bottom of the sampler 42 in the control system 4 for bubbles in liquid film and the bottom of the megasonic generator 43 to be at the same level, so that the sampler 42 can obtain the liquid in the liquid film 5. In these embodiments, since the other components of the control system 4 for bubbles in liquid film and the megasonic generator 43 are both mounted on the robot 2, the other components of the control system 4 for bubbles in liquid film and the megasonic generator 43 may not have a direct connection relationship, and may or may not contact each other.

[0042] It should be noted that the mounting frame in this embodiment is not equivalent to the mounting component 41. The mounting frame is used to fix the megasonic generator 43 on the robot arm 2, and the mounting component 41 is used to install the sampler 42 in the control system 4 of the bubbles in the liquid film. For example, the sampler 42 can be installed on the mounting frame through the mounting component 41.

[0043] Continue to see Figure 1, an embodiment of the present application provides a control system 4 for controlling bubbles in a liquid film on a wafer when a 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 liquid in a liquid film 5 on a wafer 6 during the period when 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 to 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, and is used to adjust the operating parameters of the megasonic generator 43 according to the bubble parameters, so that the bubble parameters are within a preset range.

[0044] 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 so that the bubble parameters are 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 expansion and contraction vibration of the bubbles and causing damage to the graphic structure on the wafer, thereby improving the wafer production yield.

[0045] The bubble detection module 44 in the embodiment of the present application may be, but is not limited to, an NTA nanoparticle tracking instrument, which can be used to monitor bubble parameters and analyze bubble parameters in a sample in real time. The controller 45 may include, but is not limited to, a receiver and a computer, which can be used to receive the bubble parameters sent by the bubble detection module 44 in real time and perform real-time analysis. When the bubble parameters are monitored to reach the set warning value for the occurrence of the "cavitation effect", the operating parameters of the megasonic generator 43 are automatically adjusted, thereby adjusting the bubble size and / or bubble concentration to a preset range to avoid the occurrence of the "cavitation effect" of the bubble.

[0046] 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.

[0047] See also Figure 2In some embodiments, the control system 4 for 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 used to provide the sampler 42 with power for obtaining liquid in the liquid film 5 during the cleaning of the wafer 6. The liquid pump 46 obtains liquid in the liquid film 5 during the cleaning of the wafer 6 through the sampler 42, and transports the liquid to the bubble detection module 44. By providing the liquid pump 46, it is convenient to obtain the liquid in the liquid film 5 on the wafer 6.

[0048] See also Figure 3 , Figure 3 4 is a front view of the sampler 42 and the mounting assembly 41. In some embodiments, the control system 4 for bubbles in the liquid film further includes a mounting assembly 41, which includes: a mounting plate 411 and at least one fixing member 412. The mounting plate 411 is connected to the megasonic generator 43 and fixed to the robot arm 2. The fixing member 412 is fixed to the mounting plate 411, and the fixing member 412 is used to fix the sampler 42.

[0049] In this embodiment, the mounting plate 411 and the megasonic generator 43 can be detachably connected to facilitate replacement of the mounting plate 411, so as to avoid the problem of complicated replacement due to damage of the mounting plate 411 due to long-term use. In addition, a plurality of fixings 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.

[0050] Continue to see Figure 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 a protrusion (not shown) matched with the first fixing hole 413, and the protrusion matches with the first fixing hole 413 to fix the fixing member 412. For example, the protrusion can be a cylinder matched with the first fixing hole 413, refer to Figure 3 , the protrusion is inserted into the first fixing hole 413 along the direction inward toward the paper surface.

[0051] 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, and the like.

[0052] In some embodiments, the fixing member 412 is provided with at least one second fixing hole (not shown), the second fixing hole is provided through the upper surface and the lower surface of the fixing member 412, and the sampler 42 is installed in the second fixing hole and passes through the lower surface of the second fixing hole to obtain the liquid in the liquid film during the wafer cleaning. Figure 3 As shown, the second fixing hole can be along Figure 3 The direction D shown in FIG. 4 penetrates the fixing member 412. The control system 4 for bubbles in the liquid film may also include a position fixing member. When the sampler 42 is adjusted in height so that its lower surface is located in the liquid film 5, the height of the sampler 42 is fixed by the position fixing member. 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 surface of the wafer.

[0053] The present application also provides a wafer cleaning method, which can be applied to Figure 4 In the wafer cleaning equipment shown, Figure 5 As shown, the wafer cleaning method comprises the following steps:

[0054] Step S501, applying a cleaning liquid to the wafer and forming a liquid film on the wafer;

[0055] Step S502, using a megasonic generator to transmit acoustic energy to the liquid film on the wafer to clean the wafer;

[0056] Step S503, obtaining liquid in the liquid film on the wafer during the wafer cleaning by the megasonic generator;

[0057] Step S504, performing bubble detection on the acquired liquid to determine bubble parameters in the liquid;

[0058] 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.

[0059] 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 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 and prevents the "cavitation effect" of the bubbles caused by excessive bubble size or excessive bubble concentration. This solves the problem in the prior art that the "cavitation effect" of the bubbles caused by the expansion and contraction vibration of the bubbles causes the collapse and damage of the graphic structure on the wafer, thereby improving the wafer production yield.

[0060] Those skilled in the art should understand that the technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the 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.

[0061] The above-mentioned embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the attached 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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