A single wafer cleaning system for improving wafer drying capability

Abstract

The application discloses a single wafer cleaning system capable of improving wafer drying capacity, and relates to the technical field of wafer cleaning systems.The single wafer cleaning system comprises a chemical integrated system, a cleaning and drying system and a recovery and storage system, the chemical integrated system is connected with the cleaning and drying system, the cleaning and drying system is connected with the recovery and storage system, and the cleaning and drying system comprises a supercritical drying module.The supercritical drying module comprises an inner shell body and an outer shell body which is slidably sleeved outside the inner shell body, the inner side of the inner shell body is provided with an inner cavity, the inner side of the outer shell body is provided with an outer cavity, and the middle part of the inner cavity is provided with a wafer bearing platform.The wafer cleaning process in the application can effectively remove impurities, particles and pollutants on the surface of a wafer, ensure the cleanliness and flatness of the surface, effectively improve the problem of pattern collapse, and ensure the yield of the overall semiconductor structure wafer product.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of wafer cleaning systems, and particularly relates to a single-wafer cleaning system capable of improving wafer drying capacity. BACKGROUND

[0002] With the continuous advancement of wafer manufacturing technology, the patterning structure of related nanoscale microstructure such as logic integrated circuit, memory, and micro-electro-mechanical system, etc. is involved. The size of the gate structure is continuously reduced, and the process node has been promoted from the high-popularity 28 nm to below 5 nm. The residual micro-particles or other related pollutants on the related electronic channel structure on the semiconductor wafer will affect the production process. However, in various cleaning, etching, de-gluing, film-removing, plating, grinding or multiple wet processes of the wafer, the problem of particle and pollutant removal is faced. The traditional cleaning method and drying process cannot effectively cope with the manufacturing problem of nanoscale or even near picoscale structure.

[0003] In the traditional wafer cleaning process, the wafer cleaning is followed by a drying process. The drying process is particularly important. In the traditional wafer drying process, isopropyl alcohol is mainly used for drying. However, the isopropyl alcohol molecule has a strong tension, which can easily cause the collapse of the wafer surface pattern. SUMMARY

[0004] The present application aims to provide a single-wafer cleaning system capable of improving wafer drying capacity to solve the above technical problems.

[0005] The technical solution adopted by the present application is as follows:

[0006] A single-wafer cleaning system capable of improving wafer drying capacity, comprising a chemical integrated system, a cleaning and drying system, and a recovery and storage system, wherein the chemical integrated system is connected with the cleaning and drying system, the cleaning and drying system is connected with the recovery and storage system, and the cleaning and drying system comprises a supercritical drying module, the supercritical drying module comprises an inner shell and an outer shell which is slidably sleeved outside the inner shell, the inner side of the inner shell is provided with an inner cavity, the inner side of the outer shell is provided with an outer cavity, and the middle part of the inner cavity is provided with a wafer carrying platform.

[0007] Preferably, the inner shell comprises an upper shell and a lower shell, the upper shell is engaged with the lower shell, the inner cavity is formed between the upper shell and the lower shell, the upper end of the upper shell is provided with a fluid inlet, the upper shell is provided with a transverse flow channel and a plurality of longitudinal flow channels, the transverse flow channel is in communication with the fluid inlet, the plurality of longitudinal flow channels are in communication with the transverse flow channel, and the plurality of longitudinal flow channels are opposite to the wafer carrying platform.

[0008] As a further preferred, one side of the upper shell is provided with a plurality of first discharge ports.

[0009] As a further preferred, the lower end of the lower shell is provided with a second discharge port, and the second discharge port is provided with a control valve.

[0010] As a preferred, the cleaning and drying system further comprises a mounting rack, and the supercritical drying module is arranged in the mounting rack.

[0011] As a further preferred, a wafer cleaning module is further included, and the wafer cleaning module is arranged in the mounting rack and located on the upper side of the supercritical drying module.

[0012] As a preferred, a phase transition system is further included, and the phase transition system is arranged between the cleaning and drying system and the recycling and storage system.

[0013] As a preferred, the chemical integrated system comprises a carbon dioxide conveying system and an isopropyl alcohol conveying system, and the carbon dioxide conveying system and the isopropyl alcohol conveying system are connected with the cleaning and drying system respectively.

[0014] The above technical solution has the following advantages or beneficial effects:

[0015] The wafer cleaning process in the application can effectively remove impurities, particles and pollutants on the surface of the wafer, ensure the cleanliness and flatness of the surface, and effectively improve the problem of pattern collapse, thereby ensuring the yield of the overall semiconductor structure wafer product. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 is a system diagram of the single-wafer cleaning system for improving wafer drying capacity in the application;

[0017] Figure 2 is a structural schematic diagram of the cleaning and drying system in the application;

[0018] Figure 3 is a structural schematic diagram of the supercritical drying module in the application;

[0019] Figure 4 is a structural schematic diagram of the supercritical drying module in the application;

[0020] Figure 5 is a sectional view of the inner shell in the application;

[0021] Figure 6 is a sectional view of the upper shell in the application.

[0022] In the figure: 1, chemical integrated system; 11, carbon dioxide conveying system; 12, isopropyl alcohol conveying system; 2, cleaning and drying system; 21, supercritical drying module; 22, inner shell; 23, outer shell; 24, inner cavity; 25, outer cavity; 26, wafer bearing platform; 27, upper shell; 28, lower shell; 29, fluid inlet; 290, transverse flow channel; 291, longitudinal flow channel; 292, first discharge port; 293, second discharge port; 294, mounting bracket; 295, wafer cleaning module; 296, base; 297, guide rail; 3, recovery storage system; 4, phase transition system. DETAILED DESCRIPTION

[0023] The technical solutions of the present application will be described clearly and completely below in conjunction with the drawings. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0024] In the description of the present application, it should be noted that, if the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and the like appear, the indicated orientation or positional relationship is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the indicated device or element must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application. In addition, if the terms "first", "second", "third" appear, they are only for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0025] In the description of the present application, it should be noted that, unless otherwise explicitly specified and limited, if the terms "mounting", "connection", "connection" appear, they should be understood in a broad sense, for example, they can be fixedly connected, or can be detachably connected, or integrally connected; can be mechanically connected, or can be electrically connected; can be directly connected, or can be indirectly connected through an intermediate medium; can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0026] Figure 1 is a system diagram of a single-wafer cleaning system for improving wafer drying capacity in the present application; Figure 2 is a structural schematic diagram of a cleaning and drying system in the present application; Figure 3 is a structural schematic diagram of a supercritical drying module in the present application; Figure 4 is an internal structural schematic diagram of a supercritical drying module in the present application; Figure 5 is a sectional view of an inner shell in the present application; Figure 6This is a cross-sectional view of the upper housing in this invention; please refer to [link / reference]. Figures 1 to 6 The diagram illustrates a preferred embodiment of a single-wafer cleaning system for enhancing wafer drying capabilities. The system includes a chemical integration system 1, a cleaning and drying system 2, and a recovery and storage system 3. The chemical integration system 1 is connected to the cleaning and drying system 2, and the cleaning and drying system 2 is connected to the recovery and storage system 3. The cleaning and drying system 2 includes a supercritical drying module 21. The supercritical drying module 21 includes an inner shell and an outer shell 23 slidably fitted onto the outer side 22 of the inner shell. An inner cavity 24 is provided inside the inner shell, and an outer cavity 25 is provided inside the outer shell 23. A wafer carrier platform 26 is located in the center of the inner cavity 24. In this embodiment, the chemical integration system 1 provides chemical agents, such as carbon dioxide and isopropanol, to the cleaning and drying system 2. Specifically, the chemical integration system 1 provides liquid isopropanol and gaseous carbon dioxide. The cleaning and drying system 2 is used for cleaning and drying wafers. The wafers are first cleaned and then dried. After drying, the wafers can be removed. The recycling and storage system 3 is used to recycle carbon dioxide from the cleaning and drying system 2, thus reusing the carbon dioxide.

[0027] Furthermore, as a preferred embodiment, the inner shell includes an upper shell 27 and a lower shell 28, which are fastened together, forming an inner cavity 24 between them. The upper end of the upper shell 27 is provided with a fluid inlet 29. The upper shell 27 contains a transverse flow channel 290 and several longitudinal flow channels 291. The transverse flow channel 290 communicates with the fluid inlet 29, and the several longitudinal flow channels 291 communicate with the transverse flow channel 290. The several longitudinal flow channels 291 are directly opposite the wafer carrier platform 26. In this embodiment, the supercritical drying module 21 also includes a base 296 and two guide rails 297 disposed on the base 296. The outer shell 23 is disposed on the two guide rails 297 and can slide on them, while the inner shell is disposed between the two guide rails 297 and fixed relative to them. The inner cavity 24 is closed or opened by the back-and-forth movement of the outer shell 23. When the outer casing 23 moves forward, the inner casing enters the outer casing 23; when the outer casing 23 moves backward, the inner casing detaches from the outer casing 23. The upper casing 27 within the inner casing has a convex shape, and the lower casing 28 has an inverted convex shape; the two interlock to achieve a fixed connection. The wafer carrier platform 26 is a non-contact type. A nozzle is located in the center of the wafer carrier platform 26 to spray airflow, lifting the wafer upward and suspending it. Sides are provided around the wafer carrier platform 26 to prevent the wafer from detaching from it. Figure 4As shown, several longitudinal flow channels 291 in the upper housing 27 are arranged in a ring and are directly opposite to the outer edge of the wafer carrier platform 26. A longitudinal channel is also provided in the middle of the upper housing 27, which is directly opposite to the middle of the wafer carrier platform 26. This can maintain effective diffusion and uniform distribution during the injection process of the relevant fluid medium, prevent excessive injection of medium, and avoid wafer positioning displacement and damage to the wafer surface structure by improper fluid flow.

[0028] Furthermore, as a preferred embodiment, a plurality of first discharge ports 292 are provided on one side of the upper housing 27. In this embodiment, at least two first discharge ports 292 are provided for discharging gaseous isopropanol, which is easily volatilized in the inner cavity 24 to form a gaseous state.

[0029] Furthermore, as a preferred embodiment, the lower end of the lower housing 28 is provided with a second discharge port 293, and a control valve is provided on the second discharge port 293. In this embodiment, the second discharge port 293 is used to discharge liquid carbon dioxide.

[0030] Furthermore, as a preferred embodiment, the cleaning and drying system 2 also includes a mounting frame 294, in which the supercritical drying module 21 is disposed.

[0031] Furthermore, as a preferred embodiment, it also includes a wafer cleaning module 295, which is also provided in the mounting bracket 294 and is located above the supercritical drying module 21.

[0032] Furthermore, as a preferred embodiment, a phase transition system 4 is also included, with the cleaning and drying system 2 and the recovery and storage system 3 connected by the phase transition system 4. In this embodiment, the liquid carbon dioxide emitted by the supercritical drying module 21 is converted into gaseous form through the phase transition system 4, and then enters the recovery and storage system 3 for recycling. When the phase transition system 4 converts liquid carbon dioxide into gaseous carbon dioxide, the pressure and temperature inside the phase transition system 4 need to be controlled, with the temperature controlled at 7-8 degrees Celsius and the pressure controlled at 10-160 BAR.

[0033] Furthermore, as a preferred embodiment, the chemical integrated system 1 includes a carbon dioxide delivery system 11 and an isopropanol delivery system 12, which are respectively connected to the cleaning and drying system 2. In this embodiment, the carbon dioxide delivery system 11 is used to deliver gaseous carbon dioxide into the supercritical drying module 21, and the isopropanol delivery system 12 is used to deliver liquid isopropanol into the supercritical drying module 21.

[0034] In this embodiment, isopropanol and carbon dioxide are used as the main drying solvents to dry the wafer surface. This effectively removes water molecules from the wafer surface, achieving the ultimate drying capability of the wafer and maintaining the pattern, thus preventing pattern breakage on the wafer surface.

[0035] In this embodiment, a non-contact wafer transfer process is adopted, using a gas / fluid supercritical drying module 21 that can operate in both open and closed modes. Liquid isopropanol and supercritical fluid (carbon dioxide) are injected in stages. Through the setting of the first discharge port 292 and the second discharge port 293, effective control and management of substances such as isopropanol and supercritical fluid are achieved, thus achieving a safe design.

[0036] In this embodiment, the outer shell 23 can move relative to the inner shell, facilitating the opening or closing of the inner cavity 24 within the inner shell and enabling the wafer to enter. During the wafer drying process, the temperature and pressure of the inner cavity 24 need to be appropriately controlled to avoid excessive diffusion of isopropanol gas inside the cavity, which could slightly affect wafer positioning and patterning.

[0037] In this embodiment, liquid isopropanol is sprayed onto the surface of the wafer using an atomizing nozzle, which facilitates the uniform coverage of the isopropanol on the wafer surface.

[0038] In this embodiment, a non-contact wafer carrier platform 26 is used, which can effectively support the wafer without contact, avoiding the generation of particles or unnecessary dust that could re-contaminate the cleaned wafer due to improper contact. It can also effectively control and position the wafer, achieving effective position control when injecting liquid isopropanol or supercritical fluid.

[0039] In this embodiment, after the wafer is cleaned by the wafer cleaning module 295, the wafer is then transported to the inner cavity 24 by the wafer robot. Isopropanol is then sprayed onto the surface of the wafer to form an isopropanol film. The isopropanol film and the water film form an alternating diffusion behavior to initially remove moisture, which is the first stage of tension control. After isopropanol is thinly coated, supercritical fluid (carbon dioxide) is introduced into the wafer surface. The supercritical fluid diffuses into the inner cavity 24, making the inner cavity 24 dry. The dryness is controlled by temperature and pressure. Water molecules are incompatible with supercritical fluid, and isopropanol can partially dissolve in supercritical fluid, achieving a three-layer distribution of water, isopropanol, and supercritical fluid between the upper and lower layers. This removes water molecules from the surface, forming a stable three-layer distribution phase. The ultra-low tension of supercritical fluid, which is close to 0, prevents the patterned structure from collapsing due to the distribution tension of the two separated phases of water and isopropanol molecules during the evaporation and migration process. Furthermore, supercritical fluid is placed in the bottom layer that is in contact with the structure, and water molecules are removed through constant pressure and temperature.

[0040] The above description is merely a preferred embodiment of the present invention and does not limit the implementation and protection scope of the present invention. Those skilled in the art should realize that any equivalent substitutions and obvious changes made based on the description and illustrations of the present invention should be included within the protection scope of the present invention.

Claims

1. A single-wafer cleaning system for improving wafer drying capability, characterized in that, The system includes a chemical integration system, a cleaning and drying system, and a recycling and storage system. The chemical integration system is connected to the cleaning and drying system, and the cleaning and drying system is connected to the recycling and storage system. The cleaning and drying system includes a supercritical drying module, which includes an inner shell and an outer shell slidably fitted outside the inner shell. The inner shell has an inner cavity, and the outer shell has an outer cavity. A wafer carrier platform is located in the middle of the inner cavity. The system also includes a phase transition system, which is located between the cleaning and drying system and the recycling and storage system. Liquid carbon dioxide emitted by the supercritical drying module is converted into gaseous form through the phase transition system and then enters the recycling and storage system for recycling. When the phase transition system converts liquid carbon dioxide into gaseous carbon dioxide, the pressure and temperature inside the phase transition system need to be controlled, with the temperature controlled at 7-8 degrees Celsius and the pressure controlled at 10-160 BAR.

2. The single-wafer cleaning system for improving wafer drying capability as described in claim 1, characterized in that, The inner housing includes an upper housing and a lower housing, the upper housing and the lower housing are fastened together, and the inner cavity is formed between the upper housing and the lower housing. The upper end of the upper housing is provided with a fluid inlet. The upper housing is provided with a transverse flow channel and a plurality of longitudinal flow channels. The transverse flow channel is connected to the fluid inlet, the plurality of longitudinal flow channels are connected to the transverse flow channel, and the plurality of longitudinal flow channels are directly opposite the wafer carrier platform.

3. The single-wafer cleaning system for improving wafer drying capability as described in claim 2, characterized in that, The upper shell has several first discharge ports on one side.

4. The single-wafer cleaning system for improving wafer drying capability as described in claim 2, characterized in that, The lower end of the lower housing is provided with a second discharge port, and a control valve is provided on the second discharge port.

5. The single-wafer cleaning system for improving wafer drying capability as described in claim 1, characterized in that, The cleaning and drying system also includes a mounting frame, and the supercritical drying module is located inside the mounting frame.

6. The single-wafer cleaning system for improving wafer drying capability as described in claim 5, characterized in that, It also includes a wafer cleaning module, which is located inside the mounting bracket and is situated above the supercritical drying module.

7. The single-wafer cleaning system for improving wafer drying capability as described in claim 1, characterized in that, The integrated chemical system includes a carbon dioxide delivery system and an isopropanol delivery system, which are respectively connected to the cleaning and drying system.

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