Wafer cleaning device

Abstract

The utility model provides a wafer cleaning device. The wafer cleaning device comprises a cleaning cavity, a first bearing table and a cleaning assembly, wherein the first bearing table and the cleaning assembly are arranged in the cleaning cavity; the first bearing table is used for bearing a wafer and can drive the wafer to rotate; the cleaning assembly and the first bearing table are arranged in a spaced mode, the cleaning assembly extends in the radial direction of the first bearing table, the cleaning assembly can stretch out and draw back in the extending direction of the cleaning assembly, and the cleaning assembly is used for spraying cleaning liquid to a wafer on the first bearing table. According to the cleaning device, the telescopic cleaning assembly is arranged in the cleaning cavity, the cleaning device can be suitable for spraying and cleaning wafers of different sizes, the applicability of the cleaning device is improved, secondary pollution to the wafers is reduced through the improved cleaning device, the production cost is reduced, and the production efficiency is improved. And the cleaning and production efficiency is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of semiconductor equipment, in particular to a wafer cleaning device. Background Art

[0002] After the wafers arrive, they need to be sampled and inspected to ensure that the quality of the wafers meets the production standards. After the inspection is completed, the surface of the wafers needs to be thoroughly cleaned, because after the packaging wafers arrive, workers will find that there are frequent contamination particles on their surface. In addition, the heating and baking process in the production process may cause contamination particles to adhere to the surface of the chip, which is difficult to remove. Therefore, inspection and cleaning are carried out when the wafers arrive. This process helps to clarify the quality problems of the incoming materials and ensure the production quality of the next production stage.

[0003] Currently, wafer cleaning equipment is not compatible with wafers of different sizes, resulting in each device only being able to effectively clean wafers of a specific size. This limitation means that in order to process wafers of multiple sizes, more machines and costs must be invested, which cannot meet the needs of efficient production and increases production costs. Utility Model Content

[0004] The utility model aims to provide a wafer cleaning device, which can be suitable for cleaning wafers of different sizes, thereby improving the applicability of the cleaning device, reducing production costs, and improving cleaning efficiency.

[0005] To achieve the above-mentioned purpose, in a first aspect, the utility model provides a wafer cleaning device, comprising a cleaning chamber and a first carrier and a cleaning component arranged in the cleaning chamber;

[0006] The first carrying platform is used to carry the wafer and can drive the wafer to rotate;

[0007] The cleaning component is spaced apart from the first carrier platform, extends radially along the first carrier platform, and is retractable along the extending direction, and is used to spray cleaning liquid onto the wafer on the first carrier platform.

[0008] The beneficial effect of the wafer cleaning device provided by the utility model is that by arranging a retractable cleaning component in the cleaning chamber, it can be suitable for spray cleaning of wafers of different sizes, thereby improving the applicability of the cleaning device, reducing production costs, and improving cleaning efficiency.

[0009] In some embodiments, the cleaning assembly includes a driving member, a fixing member, and a telescopic member;

[0010] One end of the fixing member is arranged on the inner side wall of the cleaning cavity, and the fixing member is provided with a first channel along its axial direction, and the first channel extends to the other end of the fixing member;

[0011] The telescopic member is movably disposed in the first channel, the telescopic member is provided with a second channel for conveying cleaning liquid along its axial direction, the outer side wall of the telescopic member is provided with a first liquid discharge hole corresponding to the first bearing platform, and the first liquid discharge hole is communicated with the second channel;

[0012] The driving member is arranged in the first channel, and is used to drive the telescopic member to extend and retract. The beneficial effect is that the telescopic member is movably arranged in the first channel, and cooperates with the driving member, so that the telescopic member can be extended and retracted, and the cleaning liquid is discharged through the first liquid discharge hole on the telescopic member. When the telescopic member is extended, the spraying radius is increased, thereby improving the applicability of the cleaning device.

[0013] In some embodiments, the outer wall of the fixing member is provided with a second liquid discharge hole and a liquid inlet hole, both of which are connected to the first channel, and the second liquid discharge hole is arranged corresponding to the first supporting platform, the liquid inlet hole is used to connect the liquid inlet pipe, and the first channel is connected to the second channel. The beneficial effect is that by providing the second liquid discharge hole and the liquid inlet hole on the fixing member, the liquid can be input through the liquid inlet hole, and can flow into the second channel through the first channel, and the cleaning liquid can also be discharged through the second liquid discharge hole, so as to further increase the spray radius of the cleaning device.

[0014] In some embodiments, the driving member includes a connecting portion and a telescopic portion, the telescopic portion is telescopically connected to the connecting portion, and the diameters of the connecting portion and the telescopic portion are both smaller than the inner diameter of the second channel, the connecting portion is fixedly disposed in the first channel, a first gap is formed between an outer side wall of the connecting portion and an inner side wall of the first channel, an end of the telescopic portion away from the connecting portion is connected to the second channel, and a second gap is formed between an outer side wall of the telescopic portion and an inner side wall of the second channel;

[0015] When the telescopic part telescopes, the telescopic member can be driven to move. The beneficial effect is that the driving member includes a connecting part and a telescopic part, and by setting the diameters of the connecting part and the telescopic part to be smaller than the inner diameter of the second channel, the installation of the driving member and the telescopic part are facilitated, and the driving member does not block the first channel and the second channel, so that the cleaning liquid can be discharged from the first drainage hole and the second drainage hole through the first gap and the second gap.

[0016] In some embodiments, the cleaning assembly further comprises a seal;

[0017] An annular sealing groove is provided in the first channel, and the sealing groove is arranged close to the telescopic member;

[0018] The sealing member is arranged in the sealing groove and contacts the outer wall of the telescopic member. The beneficial effect is that the sealing member is arranged in the first channel to ensure the sealing between the fixed member and the telescopic member, avoid the overflow of the cleaning liquid, and improve the reliability of the cleaning liquid transportation.

[0019] In some embodiments, the wafer cleaning device further includes a detection chamber and a second carrier and a detector disposed in the detection chamber;

[0020] The second carrying platform is used for carrying the wafer;

[0021] The detector is located at the top of the detection chamber and is arranged corresponding to the second carrier, and the detector is used to detect defects and contamination on the surface of the wafer. The beneficial effect is that by arranging the detector in the detection chamber to detect defects and contamination on the surface of the wafer, abnormal types of wafers can be judged, which is convenient for classifying and processing abnormal types of wafers.

[0022] In some embodiments, the wafer cleaning apparatus further includes a controller;

[0023] The detector is an image detector, and the image detector is electrically connected to the controller;

[0024] The controller has a display screen, and the controller is used to control the image detector to perform detection, and display the detection results through the display screen. Its beneficial effect is that the image detector is controlled by the controller to detect the surface of the wafer, so as to determine whether there are contaminated particles, and because the controller has a display screen, the detection results can be directly displayed on the display screen, and abnormal wafers can be magnified and confirmed as needed.

[0025] In some embodiments, the detection cavity is arranged in close contact with a side wall of the cleaning cavity, and a first window that can be opened and closed is provided between the detection cavity and the cleaning cavity;

[0026] The detection chamber is also provided with a first manipulator, which is used to transfer the wafer on the second carrier to the first carrier through the first window. The beneficial effect is that by fitting the detection chamber and the cleaning chamber together and providing the first window between the two, the wafer can be transferred inside the chamber to avoid contamination of the wafer by the external environment.

[0027] In some embodiments, the wafer cleaning device further includes a loading and unloading cavity and a third carrier and a second robot disposed in the loading and unloading cavity;

[0028] The loading and unloading cavity is arranged on the other side wall of the cleaning cavity;

[0029] The third carrying platform is used to carry the wafer;

[0030] The second robot is used to transfer the wafer on the first carrier to the third carrier.

[0031] In some embodiments, the loading and unloading cavity is arranged in close contact with the other side wall of the cleaning cavity, and the loading and unloading cavity and the detection cavity are respectively located on two opposite sides of the cleaning cavity;

[0032] A second window that can be opened and closed is provided between the loading and unloading cavity and the cleaning cavity;

[0033] The second manipulator is used to transfer the wafer on the first carrier to the third carrier through the second window. The beneficial effect is that by fitting the loading and unloading chamber with the cleaning chamber and setting the second window between the two, the wafer can be transferred inside the chamber to avoid contamination of the wafer by the external environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 A schematic diagram of the structure of a wafer cleaning device according to an embodiment of the present invention;

[0035] Figure 2 A schematic diagram of the structure of the cleaning assembly of the embodiment provided by the utility model;

[0036] Figure 3 A cross-sectional view of the cleaning assembly of the embodiment provided by the utility model along its axial direction;

[0037] Figure 4 for Figure 3 Detailed view of point A in the middle.

[0038] Reference numerals:

[0039] Cleaning chamber 1, first supporting platform 2, cleaning assembly 3, driving member 31, connecting part 311, telescopic part 312, fixing member 32, first channel 321, second liquid drainage hole 322, liquid inlet hole 323, telescopic member 33, second channel 331, first liquid drainage hole 332, sealing member 4, detection chamber 5, second supporting platform 6, detector 7, controller 8, loading and unloading chamber 9, third supporting platform 10, second manipulator 11. DETAILED DESCRIPTION

[0040] In order to make the purpose, technical solution and advantages of the utility model clearer, the technical solution in the embodiment of the utility model will be clearly and completely described below in conjunction with the drawings of the utility model. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the utility model. Unless otherwise defined, the technical terms or scientific terms used herein should be the usual meanings understood by people with general skills in the field to which the utility model belongs. "Including" and similar words used in this article mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. Unless otherwise specified, the "connection" described in this article can be a direct connection or an indirect connection, that is, a connection through an intermediate.

[0041] In view of the problems existing in the prior art, the embodiment of the utility model provides a wafer cleaning device, referring to Figures 1 to 3 As shown, the wafer cleaning device includes a cleaning chamber 1 and a first carrier 2 and a cleaning assembly 3 arranged in the cleaning chamber 1. The first carrier 2 is used to carry the wafer and can drive the wafer to rotate. The cleaning assembly 3 is located above the first carrier 2 and is spaced apart from the first carrier 2. The cleaning assembly 3 extends in the radial direction of the first carrier 2, and the cleaning assembly 3 can be retracted in the direction of its extension. The cleaning assembly 3 is used to spray the cleaning liquid on the wafer on the first carrier 2.

[0042] In this embodiment, the first carrier 2 is a disc-shaped structure and can rotate around its axis to drive the wafer to rotate. The first carrier 2 can fix wafers of different sizes, such as 6-inch, 8-inch or 12-inch wafers. The cleaning component 3 is arranged in parallel with the first carrier 2, and the cleaning component 3 extends along the radial direction of the first carrier 2. Since the cleaning component 3 is retractable, it can be used for spray cleaning of wafers of different sizes, thereby improving the applicability of the cleaning device, reducing production costs, and improving cleaning efficiency.

[0043] It is understandable that, in general, the cleaning component 3 and the first carrier 2 are spaced apart in the vertical axis. Of course, in actual use, the relative position of the cleaning component 3 and the first carrier 2 depends on the actual application scenario. For example, the cleaning component 3 and the first carrier 2 are at a certain angle to the axis.

[0044] In some embodiments, reference Figures 1 to 3As shown, the cleaning assembly 3 includes a driving member 31, a fixing member 32 and a telescopic member 33. One end of the fixing member 32 is fixedly connected to the inner side wall of the cleaning chamber 1. The fixing member 32 is provided with a first channel 321 along its axial direction, and the first channel 321 extends to the other end of the fixing member 32. The telescopic member 33 is movably arranged in the first channel 321. The telescopic member 33 is provided with a second channel 331 for conveying cleaning liquid along its axial direction. The outer side wall of the telescopic member 33 is provided with a first drainage hole 332 corresponding to the first bearing platform 2. The first drainage hole 332 is connected with the second channel 331. The driving member 31 is arranged in the first channel 321 to drive the telescopic member 33 to extend and retract.

[0045] In this embodiment, one end of the fixing member 32 is fixedly connected to the inner side wall of the cleaning chamber 1, and the first channel 321 opened along the axial direction of the fixing member 32 can be used to transport the cleaning liquid and also to accommodate the telescopic member 33 and the driving member 31. The second channel 331 opened in the telescopic member 33 is connected to the first channel 321, and the outer side wall of the telescopic member 33 is provided with a plurality of first drainage holes 332 spaced along the axial direction thereof. The first drainage holes 332 can discharge the cleaning liquid in the second channel 331 to the wafer on the first carrier 2, thereby cleaning the wafer.

[0046] It is understandable that, since the outer wall of the telescopic member 33 is provided with a plurality of the first liquid drain holes 332 spaced apart along its axial direction, when the driving member 31 drives the telescopic member 33 to extend out of the first channel 321, the plurality of the first liquid drain holes 332 located outside the first channel 321 can spray the cleaning liquid onto the wafer on the first carrier 2, thereby increasing the spraying radius. When the telescopic member 33 retracts, part of the first liquid drain holes 332 is moved into the first channel 321, thereby reducing the spraying radius. Therefore, by controlling the extension and retraction of the telescopic member 33, the wafer cleaning device is suitable for cleaning wafers of different sizes.

[0047] Furthermore, the outer side wall of the fixing member 32 is provided with a second liquid discharge hole 322 and a liquid inlet hole 323, and both the second liquid discharge hole 322 and the liquid inlet hole 323 are connected to the first channel 321. The second liquid discharge hole 322 is provided corresponding to the first supporting platform 2, and a plurality of the second liquid discharge holes 322 are arranged at intervals along the axial direction of the fixing member 32. The liquid inlet hole 323 is located on the upper side wall of the fixing member 32 and is connected to one end of the liquid inlet pipe, and the other end of the liquid inlet pipe is used to be connected to an external liquid supply source.

[0048] In this embodiment, a plurality of second drainage holes 322 are arranged at intervals along the axial direction of the outer wall of the fixing member 32, so when the telescopic member 33 extends from the first channel 321, the second drainage holes 322 and the first drainage holes 332 can spray cleaning liquid toward the wafer together.

[0049] It should be noted that when the second drainage hole 322 and the first drainage hole 332 need to discharge liquid at the same time, in order to avoid the outer wall of the telescopic member 33 blocking the second drainage hole 322 during the drainage process, the telescopic member 33 can be driven to move by the driving member 31 so that the first drainage hole 332 located in the first channel 321 overlaps with the second drainage hole 322.

[0050] In some embodiments, the liquid inlet pipe may be connected to the second channel 331, and the cleaning liquid may be directly injected into the second channel 331 to realize the delivery of the cleaning liquid. In this case, the liquid inlet pipe inputs the cleaning liquid into the second channel 331, and the cleaning liquid may be discharged to the wafer on the first carrier 2 through the first liquid discharge hole 332.

[0051] In some embodiments, reference Figure 3 As shown, the driving member 31 includes a connecting portion 311 and a telescopic portion 312, the telescopic portion 312 is telescopically connected to the connecting portion 311, and the diameters of the connecting portion 311 and the telescopic portion 312 are both smaller than the inner diameter of the second channel 331, the connecting portion 311 is fixedly arranged in the first channel 321 and is coaxial with the first channel 321, and a first gap is provided between the outer wall of the connecting portion 311 and the inner wall of the first channel 321, and one end of the telescopic portion 312 away from the connecting portion 311 is connected to the second channel 331, and a second gap is provided between the outer wall of the telescopic portion 312 and the inner wall of the second channel 331, and when the telescopic portion 312 telescopes, it can drive the telescopic member 33 to move.

[0052] In this embodiment, the driving member 31 may be a telescopic hydraulic rod, and when hydraulic pressure is applied to the connecting portion 311, the telescopic portion 312 extends to drive the telescopic member 33 to extend. When the hydraulic pressure in the connecting portion 311 is withdrawn, the telescopic portion 312 drives the telescopic member 33 to retract.

[0053] In some embodiments, the driving member 31 may also be a telescopic cylinder.

[0054] In some embodiments, reference Figure 3 and Figure 4As shown, an annular sealing groove is opened in the first channel 321, and the sealing groove is arranged close to the telescopic member 33. The cleaning component 3 also includes a sealing member 4, which is adapted to the sealing groove. The sealing member 4 is arranged in the sealing groove and contacts the outer wall of the telescopic member 33.

[0055] In this embodiment, the sealing member 4 is a sealing ring with a certain elasticity. The sealing member 4 is arranged in the first channel 321 to ensure the sealing between the fixing member 32 and the telescopic member 33, thereby avoiding the overflow of the cleaning liquid and improving the reliability of the cleaning liquid transportation.

[0056] In some embodiments, reference Figure 1 As shown, the wafer cleaning device further includes a detection chamber 5, a second carrier 6 and a detector 7 arranged in the detection chamber 5, wherein the second carrier 6 is used to carry the wafer, and the detector 7 is located at the top of the detection chamber 5 and is arranged corresponding to the second carrier 6. The detector 7 is used to detect defects and contamination on the surface of the wafer.

[0057] In this embodiment, the detector 7 is arranged corresponding to the center of the second carrier 6, and the detector 7 is arranged in the detection cavity 5 to detect defects and contamination on the surface of the wafer to determine abnormal wafer types. The abnormal wafer types include wafers with contamination particles on the surface, wafers with defects on the surface, and wafers with both contamination particles and defects on the surface.

[0058] Specifically, the wafer cleaning device further includes a controller 8, and the detector 7 is an image detector 7, and the image detector 7 is electrically connected to the controller 8. The controller 8 has a display screen, and the controller 8 is used to control the image detector 7 to perform detection, and display the detection result through the display screen, so that the staff can accurately and timely determine whether there is contamination and defects on the surface of the wafer.

[0059] It should be noted that the detection results include classification results for abnormal types of wafers. The detection results facilitate the staff to judge each wafer and eliminate defective and contaminated wafers, thereby reducing the cost of packaging and reducing the waste of packaging materials.

[0060] Furthermore, a side wall of the detection chamber 5 is arranged in close contact with a side wall of the cleaning chamber 1, and a first window that can be opened and closed is provided between the detection chamber 5 and the cleaning chamber 1. A first manipulator is also provided in the detection chamber 5, and the first manipulator is used to transfer the wafer on the second carrier 6 to the first carrier 2 through the first window. After the wafer is cleaned in the cleaning chamber 1, the first manipulator transfers the wafer from the first carrier 2 to the second carrier 6.

[0061] In this embodiment, the detection chamber 5 and the cleaning chamber 1 are fitted together and a first window is provided between the two, so as to realize the transfer of the wafer inside the chamber and avoid the contamination of the wafer by the external environment.

[0062] It should be noted that when the wafer arrives, it needs to be placed in the detection chamber 5 for inspection first to determine whether there are contaminated particles on the surface of the wafer. If there are contaminated particles, the wafer needs to be transferred to the cleaning chamber 1 for cleaning. After the cleaning process is completed, the wafer is transferred to the detection chamber 5 for inspection. This step can be repeated until the cleanliness of the wafer surface detected in the detection chamber 5 meets the process standard requirements.

[0063] Continue to refer Figure 1 As shown, in some embodiments, the wafer cleaning device also includes a loading and unloading chamber 9 and a third loading platform 10 and a second robot 11 arranged in the loading and unloading chamber 9, the loading and unloading chamber 9 is arranged on the other side wall of the cleaning chamber 1, the third loading platform 10 is used to carry the wafer, and the second robot 11 is used to transfer the wafer on the first loading platform 2 to the third loading platform 10.

[0064] In this embodiment, when the wafer surface cleanliness is detected to meet the process standard requirements in the detection chamber 5, the first manipulator is used to transfer the wafer to the first carrier 2, and then the second manipulator 11 is used to transfer the wafer to the third carrier 10, thereby completing the loading of the wafer. When unloading is required, the wafer on the third carrier 10 can be transferred out of the loading and unloading chamber 9 by the second manipulator 11.

[0065] Furthermore, the loading and unloading chamber 9 is arranged to fit with the other side wall of the cleaning chamber 1, and the loading and unloading chamber 9 and the detection chamber 5 are respectively located on the opposite sides of the cleaning chamber 1, and a second window that can be opened and closed is provided between the loading and unloading chamber 9 and the cleaning chamber 1, and the second robot 11 is used to transport the wafer on the first supporting platform 2 to the third supporting platform 10 through the second window.

[0066] In this embodiment, the loading and unloading chamber 9 is fitted with the cleaning chamber 1 and a second window is provided between the two, so as to realize the transfer of the wafer inside the chamber and avoid the contamination of the wafer by the external environment.

[0067] The above is only a specific implementation of the embodiment of the present application, but the protection scope of the embodiment of the present application is not limited thereto, and any changes or replacements within the technical scope disclosed in the embodiment of the present application should be included in the protection scope of the embodiment of the present application. Therefore, the protection scope of the embodiment of the present application should be based on the protection scope of the claims.

Claims

1. A wafer cleaning device, characterized in that: It comprises a cleaning cavity and a first supporting platform and a cleaning component arranged in the cleaning cavity; The first carrying platform is used to carry the wafer and can drive the wafer to rotate; The cleaning component is spaced apart from the first carrier platform, extends radially along the first carrier platform, and is retractable along the extending direction, and is used to spray cleaning liquid onto the wafer on the first carrier platform.

2. The wafer cleaning device according to claim 1, characterized in that: The cleaning assembly includes a driving member, a fixing member and a telescopic member; One end of the fixing member is arranged on the inner side wall of the cleaning cavity, and the fixing member is provided with a first channel along its axial direction, and the first channel extends to the other end of the fixing member; The telescopic member is movably disposed in the first channel, the telescopic member is provided with a second channel for conveying cleaning liquid along its axial direction, the outer side wall of the telescopic member is provided with a first liquid discharge hole corresponding to the first bearing platform, and the first liquid discharge hole is communicated with the second channel; The driving member is disposed in the first channel, and is used for driving the telescopic member to telescope.

3. The wafer cleaning device according to claim 2, characterized in that: The outer wall of the fixing member is provided with a second liquid discharge hole and a liquid inlet hole, both of which are connected to the first channel, and the second liquid discharge hole is arranged corresponding to the first supporting platform, the liquid inlet hole is used to connect the liquid inlet pipe, and the first channel is connected to the second channel.

4. The wafer cleaning device according to claim 2 or 3, characterized in that: The driving member includes a connecting portion and a telescopic portion, the telescopic portion is telescopically connected to the connecting portion, and the diameters of the connecting portion and the telescopic portion are both smaller than the inner diameter of the second channel, the connecting portion is fixedly arranged in the first channel, a first gap is formed between the outer wall of the connecting portion and the inner wall of the first channel, an end of the telescopic portion away from the connecting portion is connected to the second channel, and a second gap is formed between the outer wall of the telescopic portion and the inner wall of the second channel; When the telescopic portion telescopes, the telescopic member can be driven to move.

5. The wafer cleaning device according to claim 2, characterized in that: The cleaning assembly also includes a sealing member; An annular sealing groove is provided in the first channel, and the sealing groove is arranged close to the telescopic member; The sealing member is disposed in the sealing groove and contacts the outer side wall of the telescopic member.

6. The wafer cleaning device according to claim 1, characterized in that: It also includes a detection cavity and a second carrier and a detector arranged in the detection cavity; The second carrying platform is used for carrying the wafer; The detector is located at the top of the detection cavity and is arranged corresponding to the second supporting platform. The detector is used to detect defects and contamination on the surface of the wafer.

7. The wafer cleaning device according to claim 6, characterized in that: Also includes a controller; The detector is an image detector, and the image detector is electrically connected to the controller; The controller has a display screen, and is used to control the image detector to perform detection and display the detection result through the display screen.

8. The wafer cleaning device according to claim 6, characterized in that: The detection cavity is arranged in close contact with a side wall of the cleaning cavity, and a first window that can be opened and closed is provided between the detection cavity and the cleaning cavity; A first robot is also provided in the detection chamber, and the first robot is used to transport the wafer on the second carrier to the first carrier through the first window.

9. The wafer cleaning device according to claim 6, characterized in that: It also includes a loading and unloading cavity and a third bearing platform and a second manipulator arranged in the loading and unloading cavity; The loading and unloading cavity is arranged on the other side wall of the cleaning cavity; The third carrying platform is used for carrying the wafer; The second robot is used to transfer the wafer on the first carrier to the third carrier.

10. The wafer cleaning device according to claim 9, characterized in that: The loading and unloading cavity is arranged in close contact with the other side wall of the cleaning cavity, and the loading and unloading cavity and the detection cavity are respectively located on two opposite sides of the cleaning cavity; A second window that can be opened and closed is provided between the loading and unloading cavity and the cleaning cavity; The second robot is used to transport the wafer on the first carrier stage to the third carrier stage through the second window.

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