An alignment system and method

Abstract

The present application discloses an alignment system and method, which can be applied to the field of semiconductor technology. The system includes: an equipment front-end module and a process module; the equipment front-end module includes a robotic arm, a first pre-alignment device, and a second pre-alignment device; when picking up a wafer, the robotic arm is used to transport the wafer from the wafer cassette to the first pre-alignment device, and transport the tray from the tray cassette to the second pre-alignment device; the first pre-alignment device is used to pre-align the wafer; the second pre-alignment device is used to pre-align the tray; the robotic arm is further used to transport the pre-aligned wafer above the pre-aligned tray, and the second pre-alignment device is used to place the wafer into the tray; the robotic arm is further used to transport the tray carrying the wafer to the process module; the process module is used to receive the tray and perform a process on the wafer carried by the tray. Thus, by pre-aligning the wafer and the tray respectively through two pre-alignment devices, the number of handling times is reduced and the pre-alignment accuracy is improved.

Description

Technical Field

[0001] This application relates to the field of semiconductor technology, and particularly to an alignment system and method. Background Art

[0002] In high-temperature processes such as wafer CVD (Chemical Vapor Deposition) and annealing, due to the discontinuity of the medium at the wafer edge and around it, it is easy to cause inconsistent heating between the wafer edge and the wafer interior, which in turn causes the wafer to warp and reduces the product yield. Therefore, in the industry, a tray is commonly used to carry the wafer, and the tray and the wafer are placed in the process chamber together for high-temperature processes.

[0003] If the wafer is manually loaded into the tray and then the tray carrying the wafer is placed in the process chamber, it is difficult to ensure cleanliness and production efficiency. Therefore, an automatic alignment system is introduced. However, the existing automatic alignment systems usually adopt a structure combining a pre-alignment device and a buffer area. The alignment process involves multiple transfers of the wafer and the tray, which easily causes the pre-aligned wafer or tray to shift again, resulting in a problem of low pre-alignment accuracy.

[0004] Therefore, how to improve the pre-alignment accuracy is an urgent problem for those skilled in the art. Summary of the Invention

[0005] Based on the above problems, this application provides an alignment system and method. By using two pre-alignment devices to pre-align the wafer and the tray respectively, the number of transfers is reduced and the pre-alignment accuracy is improved.

[0006] In a first aspect, an embodiment of this application provides an alignment system, including: an equipment front-end module and a process module;

[0007] The equipment front-end module includes a robotic arm, a first pre-alignment device, and a second pre-alignment device;

[0008] When picking up the wafer, the robotic arm is used to transfer the wafer from the wafer cassette to the first pre-alignment device, and transfer the tray from the tray cassette to the second pre-alignment device;

[0009] The first pre-alignment device is used to pre-align the wafer;

[0010] The second pre-alignment device is used to pre-align the tray;

[0011] The robotic arm is further used to transfer the pre-aligned wafer above the pre-aligned tray, and the second pre-alignment device is used to place the wafer into the tray;

[0012] The robotic arm is also used to transport the tray carrying the wafer to the process module; the process module is used to receive the tray and perform processes on the wafer carried by the tray.

[0013] Optionally, the first pre-alignment device includes: a first linear sensor, a first lifting component, and a first rotating platform;

[0014] When the first lifting component rises, it is used to dock with the robotic arm and receive the wafer transported by the robotic arm;

[0015] When the first lifting component descends, it is used to dock with the first rotating platform and place the wafer on the first rotating platform;

[0016] The first rotating platform is used to fix the wafer and drive the wafer to rotate;

[0017] The first linear sensor includes a first receiving end and a first transmitting end. The first transmitting end is used to generate a first linear light beam directed at the first receiving end; the first receiving end is used to receive the first linear light beam blocked by the rotating wafer and determine the center of the wafer based on photoelectric conversion;

[0018] The first lifting component is also used to move the wafer after the center is determined to align the center of the wafer with the first rotating platform;

[0019] The first rotating platform is also used to perform flat-edge alignment on the wafer with the center aligned.

[0020] Optionally, the first linear light beam has a specific length, is partially blocked by the wafer fixed on the first rotating platform, and the first linear light beam is perpendicular to both the wafer and the first receiving end.

[0021] Optionally, the first lifting component includes at least three first lifting columns, and the first lifting columns are sequentially connected as vertices to form a polygon.

[0022] Optionally, all the first lifting columns are connected to the same movement control component;

[0023] The movement control component is used to control the movement of each first lifting column in the same direction.

[0024] Optionally, the second pre-alignment device includes: a second linear sensor, a second lifting component, and a second rotating platform;

[0025] During the pre-alignment process of the tray, when the second lifting component rises, it is used to dock with the robotic arm and receive the tray transported by the robotic arm;

[0026] When descending, the second lifting component is used to dock with the second rotating platform and place the tray on the second rotating platform.

[0027] The second rotating platform is used to fix the tray and drive the tray to rotate.

[0028] The second linear sensor includes a second receiving end and a second transmitting end. The second transmitting end is used to generate a second linear light beam directed at the second receiving end. The second receiving end is used to receive the second linear light beam blocked by the rotating tray and determine the center of the tray based on photoelectric conversion.

[0029] The second lifting component is also used to move the tray after the center is determined and align the center of the tray with the second rotating platform.

[0030] The second rotating platform is also used to align the flat edge of the tray with the center-aligned tray.

[0031] Optionally, the second linear light beam has a specific length, is partially blocked by the tray fixed on the second rotating platform, and the second linear light beam is perpendicular to both the tray and the second receiving end.

[0032] Optionally, the second lifting component includes at least three second lifting columns, and the second lifting columns are connected in sequence as vertices to form a polygon.

[0033] Optionally, all the second lifting columns are connected to the same movement control component.

[0034] The movement control component is used to control the movement of each second lifting column in the same direction.

[0035] Optionally, the upper surface of the tray is provided with a groove for placing the wafer, and the depth of the groove is the same as the thickness of the wafer.

[0036] The inner surface of the tray is provided with a limiting block corresponding to the flat edge of the wafer to limit the rotation of the wafer relative to the tray.

[0037] Optionally, the tray is provided with through holes whose number matches the number of the second lifting columns, and the pattern formed by the sequential connection of the through holes is the same as the polygon formed by connecting the second lifting columns in sequence as vertices.

[0038] During the process of placing the tray on the second rotating platform by the second lifting columns, the pattern formed by the sequential connection of the through holes forms a specific angle with the polygon formed by connecting the second lifting columns in sequence as vertices.

[0039] After the pre-alignment of the tray is completed, the second rotating platform rotates the tray counterclockwise by a specific angle to align the through-hole of the tray with the second lifting column, so that when the second lifting column rises, it can pass through the through-hole without lifting the tray.

[0040] Optionally, the number of the second lifting components and the number of the through-holes are both four;

[0041] The figure formed by sequentially connecting the four through-holes and the polygon formed by sequentially connecting the four second lifting columns as vertices are both rectangles; when the tray is placed on the second rotating platform by the second lifting column, the long sides of the rectangle formed by sequentially connecting the through-holes are perpendicular to the long sides of the rectangle formed by sequentially connecting the second lifting columns as vertices;

[0042] After the pre-alignment of the tray is completed, the second rotating platform rotates the tray counterclockwise by 90° to align the through-hole of the tray with the second lifting column, so that when the second lifting column rises, it can pass through the through-hole without lifting the tray.

[0043] Optionally, after the tray is rotated counterclockwise by 90°, the flat edge of the tray is at the same angle as the flat edge of the pre-aligned wafer.

[0044] Optionally, during wafer placement, the robotic arm is used to transfer the tray carrying the wafer from the process module to the second pre-alignment device;

[0045] The second pre-alignment device is used to perform pre-alignment on the tray carrying the wafer;

[0046] The robotic arm is also used to transfer the wafer on the pre-aligned tray to the wafer cassette and transfer the tray to the tray cassette.

[0047] In a second aspect, an alignment method during wafer picking provided by an embodiment of the present application is applied to the alignment system as described above and includes:

[0048] Obtaining a wafer from a wafer cassette by a robotic arm and transferring it to the first pre-alignment device for pre-alignment;

[0049] Obtaining a tray from a tray cassette by a robotic arm and transferring it to the second pre-alignment device for pre-alignment; the flat edge of the pre-aligned wafer and the flat edge of the pre-aligned tray are at the same angle;

[0050] Using the robotic arm to transfer the pre-aligned wafer above the tray and using the second pre-alignment device to place the wafer into the tray;

[0051] The tray loaded with the wafers is transported to a process module by a robotic arm for processing.

[0052] In a third aspect, an embodiment of the present application provides an alignment method during a wafer placement process, the method being applied to the alignment system described above, comprising:

[0053] Using a robotic arm to obtain the tray carrying the wafers after the process is completed from the process module and transport it to the second pre-alignment device;

[0054] Pre-aligning the tray carrying the wafer using a second pre-alignment device;

[0055] The wafers on the pre-aligned tray are transported to a wafer box by a robotic arm, and the tray is transported to a tray box.

[0056] It can be seen from the above technical solutions that compared with the existing technology, this application has the following advantages:

[0057] The present application provides an alignment system and method, the system comprising: an equipment front-end module and a process module; the equipment front-end module comprising a robotic arm, a first pre-alignment device, and a second pre-alignment device; when removing wafers, the robotic arm is used to transport the wafer from the wafer box to the first pre-alignment device, and to transport the tray from the tray box to the second pre-alignment device; the first pre-alignment device is used to pre-align the wafer; the second pre-alignment device is used to pre-align the tray; the robotic arm is also used to transport the pre-aligned wafer to the top of the pre-aligned tray, and the second pre-alignment device places the wafer into the tray; the robotic arm is also used to transport the tray carrying the wafer to the process module; the process module is used to receive the tray and process the wafer carried by the tray. Thus, the wafer and tray are pre-aligned separately by the two pre-alignment devices, which reduces the number of transports and improves the pre-alignment accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] Figure 1 A schematic structural diagram of an alignment system provided in an embodiment of the present application;

[0059] Figure 2 A schematic structural diagram of a first pre-alignment device provided in an embodiment of the present application;

[0060] Figure 3 A schematic structural diagram of a first lifting assembly provided in an embodiment of the present application;

[0061] Figure 4 A schematic diagram of the structure of a loading port provided in this application;

[0062] Figure 5 A schematic structural diagram of an end effector provided in this application;

[0063] Figure 6 Structural schematic diagram of a second pre - alignment device provided for this application;

[0064] Figure 7 Structural schematic diagram of a second lifting component provided for this application;

[0065] Figure 8 Structural schematic diagram of a tray provided for an embodiment of this application;

[0066] Figure 9 Schematic diagram of a through - hole alignment method provided for an embodiment of this application;

[0067] Figure 10 Flowchart of an alignment method during the wafer picking process provided for an embodiment of this application;

[0068] Figure 11 Schematic diagram of a wafer pre - alignment process provided for an embodiment of this application;

[0069] Figure 12 Schematic diagram of a tray pre - alignment process provided for an embodiment of this application;

[0070] Figure 13 Flowchart of a combination method provided for an embodiment of this application;

[0071] Figure 14 Schematic diagram of a process for transporting a tray carrying a wafer to a process module provided for an embodiment of this application;

[0072] Figure 15 Flowchart of an alignment method during the wafer placing process provided for an embodiment of this application. Detailed implementation manners

[0073] As described above, the existing alignment system has the problem of relatively low pre - alignment accuracy. Specifically, the existing automatic alignment system usually adopts a structure combining a pre - alignment device and a buffer area. Generally, the tray is first pre - aligned on the pre - alignment device, and after completion, the tray is transported to the buffer area. Then the wafer is transported to the pre - alignment device for pre - alignment, and after completion, the wafer is transported to the tray in the buffer area for combination. Finally, the tray carrying the wafer is moved from the buffer area to the process chamber. The entire alignment process involves multiple transports of the wafer and the tray. Since the robotic arm mostly uses the vacuum suction method to transport the wafer and the tray, it is easy for the pre - aligned wafer or tray to shift again during the picking and placing processes, resulting in the problem of relatively low pre - alignment accuracy.

[0074] To solve the above problems, an embodiment of the present application provides an alignment system, including: an equipment front-end module and a process module; the equipment front-end module includes a robotic arm, a first pre-alignment device, and a second pre-alignment device; when picking up wafers, the robotic arm is used to transport the wafers from the wafer cassette to the first pre-alignment device, and transport the trays from the tray cassette to the second pre-alignment device; the first pre-alignment device is used to pre-align the wafers; the second pre-alignment device is used to pre-align the trays; the robotic arm is further used to transport the pre-aligned wafers above the pre-aligned trays, and the second pre-alignment device is used to place the wafers into the trays; the robotic arm is further used to transport the trays carrying the wafers to the process module; the process module is used to receive the trays and perform processes on the wafers carried by the trays.

[0075] Thus, by using two pre-alignment devices to pre-align the wafers and trays respectively, the number of handling operations is reduced, and the pre-alignment accuracy is improved.

[0076] It should be noted that an alignment system and method provided by the present application can be applied to the field of semiconductor technology. The above is only an example, and the application field of the alignment system and method provided by the present application is not limited.

[0077] To make the objectives, technical solutions, and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments of the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

[0078] Figure 1 This is a schematic structural diagram of an alignment system provided by an embodiment of the present application. As shown in Figure 1 An alignment system provided by an embodiment of the present application includes: an equipment front-end module 101 and a process module 102;

[0079] The equipment front-end module 101 includes a robotic arm 201, a first pre-alignment device 202, and a second pre-alignment device 203;

[0080] When picking up wafers, the robotic arm 201 is used to transport the wafers from the wafer cassette to the first pre-alignment device 202, and transport the trays from the tray cassette to the second pre-alignment device 203;

[0081] The first pre-alignment device 202 is used to pre-align the wafers;

[0082] The second pre-alignment device 203 is used to pre-align the trays;

[0083] The robotic arm 201 is also used to carry the pre-aligned wafer above the pre-aligned tray, and the second pre-alignment device 203 places the wafer into the tray.

[0084] The robotic arm 201 is also used to carry the tray bearing the wafer to the process module 102; the process module 102 is used to receive the tray and perform a process on the wafer carried by the tray.

[0085] This application provides an alignment system, which consists of an equipment front-end module 101 (Equipment Front-End Module, EFEM) and a process module 102 PM. The equipment front-end module 101 is used to perform preparatory work before the process, such as wafer alignment, tray alignment, and the combination of the wafer and the tray. The process module 102 is used to receive the tray bearing the wafer and perform processes such as annealing and CVD, which are high-temperature operations. In the equipment front-end module 101, the embodiment of this application provides a structure in which the robotic arm 201 cooperates with a dual pre-alignment device (the first pre-alignment device 202 and the second pre-alignment device 203). The wafer and the tray are pre-aligned separately by independent devices, thereby reducing the number of transfers and improving the alignment accuracy. Specifically, the first pre-alignment device 202 corresponding to the wafer and the second pre-alignment device 203 corresponding to the tray can be set on the right side of the EFEM, and the robotic arm 201 is set in the cavity of the EFEM. When taking the wafer for the process, the robotic arm 201 first carries the wafer from the wafer cassette to the first pre-alignment device 202, and the first pre-alignment device 202 pre-aligns the wafer. Then the robotic arm 201 carries the tray from the tray cassette to the second pre-alignment device 203, and the second pre-alignment device 203 pre-aligns the tray. It should be noted that the pre-aligned wafer and tray need to meet two points. One is central alignment, and the other is that the angle between the flat edge or notch of the wafer and the tray is the same. Then, the robotic arm 201 carries the pre-aligned wafer onto the pre-aligned tray, combines them through the second pre-alignment device 203, and carries the combined tray bearing the wafer to the process module 102 for the process.

[0086] As an implementation method, regarding how to set the first pre-alignment device 202, correspondingly, the first pre-alignment device 202 includes: a first linear sensor 301, a first lifting component 302, and a first rotating platform 303;

[0087] When the first lifting component 302 rises, it is used to dock with the robotic arm 201 and receive the wafer carried by the robotic arm 201;

[0088] The first lifting assembly 302 is used to dock with the first rotating platform 303 when lowered, so as to place the wafer on the first rotating platform 303;

[0089] The first rotating platform 303 is used to fix the wafer and drive the wafer to rotate;

[0090] The first linear sensor 301 includes a first receiving end and a first transmitting end, wherein the first transmitting end is used to generate a first linear light directed toward the first receiving end; the first receiving end is used to receive the first linear light blocked by the rotating wafer and determine the center of the wafer based on photoelectric conversion;

[0091] The first lifting assembly 302 is further used to move the wafer after centering, and to align the wafer with the first rotating platform 303;

[0092] The first rotating platform 303 is also used to perform flat-edge alignment on the center-aligned wafer.

[0093] Figure 2 This is a schematic structural diagram of a first pre-alignment device provided in an embodiment of the present application. Figure 2 As shown, (a) is a side view, and (b) is a top view. The first lifting assembly 302 has a lifting function. When removing a wafer, it rises and docks with the robotic arm 201 (the docking height of the first lifting assembly 302 is higher than the upper surface height of the first rotating platform 303). The robotic arm 201 transports the wafer to the top of the first pre-alignment device 202 and slowly lowers it onto the raised first lifting assembly 302. The first lifting assembly 302 then descends and docks with the first rotating platform 303, placing the wafer on the first rotating platform 303. After receiving the wafer, the first rotating platform 303 performs a vacuum suction operation to secure the wafer and drive the wafer to rotate. The first linear sensor 301 includes a first receiving end and a first transmitting end. The first transmitting end can generate a first linear light 301A directed toward the first receiving end. When the wafer is placed on the first rotating platform 303, the first linear light 301A is partially blocked, and the blocked area changes as the wafer rotates. The first receiving end is located directly below the first linear light 301A. It receives the first linear light 301A after it is blocked by the rotating wafer. Based on photoelectric conversion, it generates a sinusoidal voltage waveform, which can be used to determine the center and flat edge position of the wafer. Furthermore, the first lifting assembly 302 also has a movement function. After determining the wafer center, the first rotating platform 303 breaks the vacuum, and the first lifting assembly 302 lifts and moves the wafer, aligning the wafer center with the center of the first rotating platform 303 before lowering it to achieve wafer center alignment. Furthermore, the first rotating platform 303 secures the wafer and rotates its flat edge to a preset angle.

[0094] It should be noted that the first linear light 301A in the embodiment of the present application is provided with a specific length (generally 0 - 10 mm, which can be linearly converted into an analog voltage of 0 - 5V), so that the wafer fixed on the first rotating platform 303 can partially block the first linear light 301A (generally set that the wafer after central alignment can block half of the length of the first linear light 301A), and the first linear light 301A is perpendicular to both the wafer and the first receiving end. It can be understood that for the convenience of calculation, the first linear light 301A is set to perpendicularly irradiate the surface of the wafer and the surface of the first receiving end.

[0095] As an implementation manner, regarding how to set the first lifting component 302, correspondingly, the first lifting component 302 includes at least three first lifting columns 401, and the respective first lifting columns 401 are connected in sequence as vertices to form a polygon.

[0096] Specifically, the area of the upper surface of a single first lifting column 401 is very small. When placing the wafer on the first lifting column 401, if the center of the upper surface of the first lifting column 401 cannot be ensured to correspond to the center of the wafer, the placement cannot be successful. And even if the placement is successful with the centers corresponding to each other, when the first lifting column 401 drives the wafer to move up and down, it is also very easy for the wafer to fall off. It can be understood that if only two first lifting columns 401 are set, because the connection line of their vertices is a straight line, the same problem also exists. For this reason, the embodiment of the present application requires at least three first lifting columns 401 to be set, and their connection lines cannot be on the same straight line, that is, the respective first lifting columns 401 are connected in sequence as vertices to form a triangle, so as to improve the stability when the wafer is placed on the first lifting column 401 and make it not easy to fall.

[0097] In addition, as an implementation manner, regarding how to set the number of the first lifting columns 401, correspondingly, the first lifting component 302 includes four first lifting columns 401, and the four first lifting columns 401 are connected in sequence as vertices to form a rectangle.

[0098] Figure 3 This is a schematic structural diagram of a first lifting component provided by an embodiment of the present application. Combining Figure 3 As shown, the first lifting component 302 provided by the embodiment of the present application is composed of 4 first lifting columns (pins) 401. Connecting the four first lifting columns 401 in sequence as vertices can obtain a rectangle.

[0099] It should be noted that if the long side direction of the rectangle is defined as the X-axis and the short side direction is defined as the Y-axis, combining Figure 3As shown, the first lifting component 302 in the embodiment of the present application is further provided with a limiting groove. The four first lifting columns 401 are connected to the same movement control component, and the movement control component can control the four first lifting columns 401 to move simultaneously in the X-axis (the long side of the rectangle) direction. It can be understood that compared with moving along the short side, the upper limit value of the moving distance is higher when moving along the long side, and thus the center alignment of the wafer can be better achieved. Specifically, taking Figure 3 the provided limiting groove as an example, it restricts the up and down displacement of the first lifting column 401, and there are vacant spaces on its left and right sides, which can allow the first lifting column 401 to move in the X-axis direction. By increasing the vacant spaces left on both sides of the limiting groove, the upper limit value of the movement of the first lifting column 401 can be increased until the overlapping part appears between the two limiting grooves, which reaches the maximum critical value. Similarly, the limiting groove can be set by rotating it clockwise by 90° when the first lifting column 401 moves up and down. The difference is that since the long side of the rectangle is shorter than the short side, in order to avoid the overlapping of the two limiting grooves, the upper limit of the vacant spaces left on both sides of the limiting groove set on the long side must be greater than that of the limiting groove set on the short side. Therefore, in the embodiment of the present application, the four first lifting columns 401 are controlled to move simultaneously in the X-axis (the long side of the rectangle) direction, so as to more conveniently set the limiting groove and improve the success rate of the center alignment of the wafer.

[0100] As an implementation manner, regarding how to set the composition of the alignment system, correspondingly, the alignment system further includes: a wafer loading port 204 and a tray loading port 205;

[0101] The wafer loading port 204 is used to place the wafer cassette and perform the operation of opening the cassette when taking the wafer.

[0102] The tray loading port 205 is used to place the tray cassette and perform the operation of opening the cassette when taking the wafer.

[0103] Figure 4 It is a schematic structural diagram of the loading port setting provided by the embodiment of the present application. Combining Figure 4 As shown, two types of loading ports (Load port) are provided at the front end of the EFEM. The wafer loading port 204 is on the left side of the front end, and the tray loading port 205 is on the right side of the front end. A card slot is provided on the wafer loading port 204, which is used in combination with the card slot at the bottom of the wafer cassette 206. The wafer cassette 206 can be fixed on the wafer loading port 204 through the card slot, and the wafer with the flat side adjusted is placed in the wafer cassette 206; a card slot is also provided on the tray loading port, which is used in combination with the card slot at the bottom of the tray cassette 207. The tray cassette 207 can be fixed on the tray loading port 205 through the card slot, and the tray with the flat side adjusted and the number corresponding to the wafer is placed in the tray cassette 207. When taking the wafer, the wafer loading port 204 and the tray loading port 205 can open the wafer cassette 206 and the tray cassette 207 respectively.

[0104] As an implementation, regarding how to set the robotic arm 201, correspondingly, the robotic arm 201 includes a central axis 208 and an end effector 209;

[0105] The central axis 208 is used to drive the end effector 209 to move;

[0106] The end effector 209 is used to carry and transport the wafer and / or the tray.

[0107] Continuing to combine with Figure 4 As shown, the robotic arm 201 provided in the embodiment of the present application includes a central axis 208 and an end effector 209. Among them, the carrying capacity of the end effector 209 is set to be compatible with carrying wafers, trays, and combinations of wafers and trays. Figure 5 This is a schematic structural diagram of an end effector provided in the embodiment of the present application. Combining with Figure 5 As shown, (a) is a top view, (b) is a side view. The width of the end effector 209 is set to be able to extend in from between two first lifting columns 401 on the short side, and the thickness is set to be able to extend into the space between the bottom of the wafer and the top of the first rotating platform 303 after the first lifting column 401 lifts the wafer to the highest point, and a certain safety margin space is maintained between the end effector 209 and the bottom of the wafer and the top of the first rotating platform 303.

[0108] As an implementation, regarding how to set the second pre-alignment device 203, correspondingly, the second pre-alignment device 203 includes: a second linear sensor 304, a second lifting component 305, and a second rotating platform 306;

[0109] During the pre-alignment of the tray, when the second lifting component 305 rises, it is used to dock with the robotic arm 201 and receive the tray transported by the robotic arm 201;

[0110] [[ID=2�]]When the second lifting component 305 descends, it is used to dock with the second rotating platform 306 and place the tray on the second rotating platform 306;

[0111] The second rotating platform 306 is used to fix the tray and drive the tray to rotate;

[0112] The second linear sensor 304 includes a second receiving end and a second transmitting end. The second transmitting end is used to generate a second linear light that shoots towards the second receiving end; the second receiving end is used to receive the second linear light blocked by the rotating tray and determine the center of the tray based on photoelectric conversion;

[0113] The second lifting assembly 305 is further used to move the tray after centering, and align the tray with the second rotating platform 306;

[0114] The second rotating platform 306 is also used to align the center-aligned tray with its flat edges.

[0115] Figure 6 This is a schematic structural diagram of a second pre-alignment device provided in an embodiment of the present application. Figure 6 As shown, (a) is a side view, and (b) is a top view. The second pre-alignment device 203 is configured in the same manner as the first pre-alignment device 202. The second lifting assembly 305 has a lifting function. When removing a wafer, it rises to dock with the robotic arm 201 (the docking height of the second lifting assembly 305 is higher than the upper surface height of the second rotating platform 306). The robotic arm 201 first moves the tray above the second pre-alignment device 203 and slowly lowers it onto the raised second lifting assembly 305. The second lifting assembly 305 then descends and docks with the second rotating platform 306, placing the tray on the second rotating platform 306. After receiving the tray, the second rotating platform 306 performs a vacuum operation to secure the tray and drive its rotation. The second linear sensor 304 includes a second receiving end and a second transmitting end. The second transmitting end generates a second linear light 304A directed toward the second receiving end. When the tray is placed on the second rotating platform 306, the second linear light 304A is partially blocked, and the blocked area varies as the wafer rotates. The second receiving end, located directly below the second linear light beam 304A, receives the second linear light beam 304A after it is blocked by the rotating tray. Based on photoelectric conversion, it generates a sinusoidal voltage waveform, which is used to determine the center and flat edge position of the tray. Furthermore, the second lifting assembly 305 also has a movement function. After determining the center of the tray, the second rotating platform 306 breaks the vacuum, raising and moving the tray. After aligning the tray center with the center of the second rotating platform 306, the second lifting assembly 305 lowers the tray, achieving center alignment. Furthermore, the second rotating platform 306 secures the tray and rotates the flat edge to a preset angle.

[0116] It should be noted that, in the embodiment of the present application, the second linear light 304A is identical to the first linear light 301A and is configured to have a specific length (typically 0-10 mm, corresponding to a linear conversion of 0-5 V to an analog voltage). Similarly, the tray secured to the second rotating platform 306 can partially block the second linear light 304A (typically, the tray, when centrally aligned, blocks half the length of the second linear light 304A). Furthermore, the second linear light 304A is perpendicular to both the tray and the second receiving end. It will be appreciated that, for ease of calculation, the second linear light 304A is configured to illuminate the tray surface and the second receiving end surface perpendicularly.

[0117] As an implementation, regarding how to set the second lifting component 305, correspondingly, the second lifting component 305 includes at least three second lifting columns 402, and the respective second lifting columns 402 are connected in sequence as vertices to form a polygon.

[0118] Specifically, the purpose of setting the second lifting columns 402 is the same as that of the first lifting column 401. The upper surface area of a single second lifting column 402 is very small. When placing the tray / or wafer on the second lifting column 402, if it is impossible to ensure that the center of the upper surface of the second lifting column 402 corresponds to the center of the tray, the placement cannot be successful. Moreover, even if the placement is successful with the centers corresponding to each other, when the second lifting column 402 drives the tray / or wafer to move up and down, it is very easy for the wafer to fall off. It can be understood that if only two second lifting columns 402 are set, since the line connecting their vertices is a straight line, the same problem also exists. For this reason, the embodiments of the present application require at least three second lifting columns 402 to be set, and their connection lines cannot be on the same straight line, that is, the respective second lifting columns 402 are connected in sequence as vertices to form a triangle, so as to improve the stability when placing the tray / or wafer on the second lifting column 402 and make it not easy to fall. As an implementation, regarding how to set the number of second lifting columns 402, correspondingly, the second lifting component 305 includes four second lifting columns 402, and the four second lifting columns 402 are connected in sequence as vertices to form a rectangle.

[0119] Figure 7 It is a schematic structural diagram of a second lifting component provided by an embodiment of the present application. In combination with Figure 7 As shown, the setting method of the second lifting component 305 is the same as that of the first lifting component 302, and it is composed of 4 second lifting columns (pins) 402. Connecting the four second lifting columns 402 in sequence as vertices can obtain a rectangle.

[0120] It should be noted that if the long side direction of the rectangle is defined as the X axis and the short side direction is defined as the Y axis, in combination with Figure 7 As shown, the second lifting component 305 in the embodiments of the present application is also provided with a limiting groove. The four second lifting columns 402 are connected to the same movement control component, and the movement control component can control the four second lifting columns 402 to move simultaneously in the X axis (the long side of the rectangle) direction, so as to more conveniently set the limiting groove and improve the success rate of wafer center alignment.

[0121] Taking the setting of 4 second lifting columns 402 as an example for illustration, as an implementation, regarding how to design the tray, correspondingly, the tray is made of silicon carbide or alumina ceramic;

[0122] The upper surface of the tray is provided with a groove for placing the wafer, and the depth of the groove is the same as the thickness of the wafer;

[0123] The inner surface of the tray is provided with limiting blocks corresponding to the flat edges of the wafer, which are used to limit the rotation of the wafer relative to the tray.

[0124] The tray is provided with four through holes matching the second lifting columns 402.

[0125] Figure 8 It is a schematic structural diagram of a tray provided by an embodiment of the present application. Combining Figure 8 As shown, in order to meet the process requirements, the tray can be made of silicon carbide (SIC) or alumina ceramic. A groove slightly larger than the outer diameter of the wafer is provided on its upper surface, and the depth is such that after the wafer is placed in the groove, the upper surface of the wafer is flush with the edge of the tray. In addition, the inner surface of the tray is provided with limiting blocks matching the notch / flat of the wafer, and when the wafer is placed on the tray, the limiting blocks can limit the rotation of the wafer relative to the tray. In addition, 4 through holes 403 matching the second lifting columns 402 are also provided at the center of the tray.

[0126] Continuing to combine Figure 8 As shown, it should be noted that for the through holes 403 of the tray provided in the embodiment of the present application, if connected in sequence as vertices, a rectangle can be obtained, and the size of this rectangle is the same as the rectangle obtained by connecting the four second lifting columns 402 in sequence as vertices.

[0127] Figure 9 It is a schematic diagram of an alignment method of through holes provided by an embodiment of the present application. Combining Figure 9 (a) As shown, when the tray is placed on the raised second lifting columns 402 by the robotic arm 201 and the tray is placed on the second rotating platform 306 by the second lifting columns 402, since the tray in the tray box is rotated by the flat edge, the long side of the rectangle formed by connecting the through holes 403 in sequence is perpendicular to the long side of the rectangle formed by connecting the second lifting columns 402 as vertices in sequence (the figure formed by connecting the through holes in sequence and the polygon formed by connecting the second lifting columns as vertices form a specific angle). The pre-alignment program can be set such that after the center alignment is completed, the second rotating platform 306 rotates the flat edge of the tray to an angle perpendicular to the long side of the rectangle formed by connecting the second lifting columns 402 as vertices in sequence. Thus, when the pre-alignment of the tray is completed, the second rotating platform 306 rotates the tray counterclockwise by 90° (a specific angle), rotates the through holes 403 of the tray to correspond to the second lifting columns 402, so that when the second lifting columns 304 rise, they can pass through the through holes 403 without lifting the tray, and then can receive the wafer and place it down for combination.

[0128] It should be noted that in the embodiment of the present application, after rotating the tray 90° counterclockwise, the long sides of the rectangle formed by the flat edge of the tray and the second lifting column 402 as vertices are connected in sequence are parallel to each other. In order to accurately place the wafer in the tray, the flat edge angle of the pre-aligned wafer should be consistent with the flat edge angle of the tray at this time (flat edge upward). Of course, if the flat edges of the wafer and the tray are both facing downward, it can also be achieved that the second lifting column 402 can pass through the through hole 403 when it is raised, and the wafer and tray can be accurately combined. The specific setting method can be flexibly adjusted by the staff.

[0129] As an embodiment, regarding how to perform alignment, when placing wafers, the robot arm 201 is used to move the tray carrying the wafers from the process module 102 to the second pre-alignment device 203;

[0130] The second pre-alignment device 203 is used to pre-align the tray carrying the wafer;

[0131] The robotic arm 201 is further configured to transport the pre-aligned wafers on the tray to the wafer box, and to transport the tray to the tray box.

[0132] During the wafer removal process, the tray carrying the wafers is transported from the second pre-alignment device 203 to the process module 102 by the robotic arm 201 and the process is carried out. When the process is completed, the process module 102 unloads the wafers, and the alignment system continues the wafer placement process. Specifically, during the wafer placement process, the robotic arm 201 first transports the tray carrying the wafers from the process module 102 to the second pre-alignment device 203. Then, the second pre-alignment device 203 pre-aligns the tray carrying the wafers. After the center alignment is completed, the second rotating platform 306 rotates the through hole 403 of the tray to correspond to the second lifting column 402, so that the second lifting column 402 can pass through the through hole 403 when it is raised, without lifting the tray, and then lifts the wafer alone, and the robotic arm 201 transports the wafer to the wafer box. Finally, the second rotating platform 306 rotates the flat edge of the pallet to an angle perpendicular to the long sides of the rectangle formed by connecting the second lifting columns 402 as vertices. The second lifting columns 402 lift the pallet and hand it over to the robotic arm 201. The robotic arm 201 moves the pallet to the pallet box, completing the entire film placement process.

[0133] In summary, the present application provides an alignment system and method. The system includes: a front-end module and a process module; the front-end module includes a robotic arm, a first pre-alignment device, and a second pre-alignment device; during wafer picking, the robotic arm is used to transfer the wafer from the wafer cassette to the first pre-alignment device and transfer the tray from the tray cassette to the second pre-alignment device; the first pre-alignment device is used to pre-align the wafer; the second pre-alignment device is used to pre-align the tray; the robotic arm is further used to transfer the pre-aligned wafer above the pre-aligned tray, and the second pre-alignment device is used to place the wafer into the tray; the robotic arm is further used to transfer the tray carrying the wafer to the process module; the process module is used to receive the tray and perform a process on the wafer carried by the tray. Thus, by using two pre-alignment devices to pre-align the wafer and the tray respectively, the number of transfers is reduced and the pre-alignment accuracy is improved.

[0134] Figure 10 The figure is a flowchart of an alignment method during wafer picking provided by an embodiment of the present application. Combining Figure 10 As shown, an embodiment of the present application provides an alignment method during wafer picking, including:

[0135] S1001: Use the robotic arm to obtain the wafer from the wafer cassette and transfer it to the first pre-alignment device for pre-alignment.

[0136] During the actual wafer picking process, first, the wafer cassette is opened by the wafer loading port, and then the robotic arm obtains the wafer from the wafer cassette and transfers it to the first pre-alignment device for pre-alignment. Specifically, Figure 11 The figure is a schematic diagram of a wafer pre-alignment process provided by an embodiment of the present application. Combining Figure 11As shown, the first lifting column first rises to the transfer height and receives the wafer from the robotic arm. Then the first lifting column descends and docks with the first rotating platform, placing the wafer on the first rotating platform for fixation. As can be seen from (a), at this time, the center of the wafer is misaligned, and there is an eccentricity e between the center of the wafer and the center of the first rotating platform. Then, the first rotating platform drives the wafer to rotate, and a part of the wafer edge will block the first linear light. Based on photoelectric conversion, a voltage waveform similar to a sine wave can be formed during the rotation of the wafer. The center point of the wafer is calculated through the waveform and the direction of the flat edge (notch / flat) of the wafer is determined. After determination, the first rotating platform drives the wafer to rotate, rotating the eccentricity e (the line connecting the center of the wafer and the center of the first rotating platform) to a direction parallel to the X-axis. Then, as shown in (b), the first lifting column rises and lifts the wafer. Then, as shown in (c), the first lifting column moves along the X-axis direction towards the center of the first rotating platform by a distance of eccentricity e to achieve the center alignment of the wafer. Finally, the first lifting column descends, places the wafer on the first rotating platform, rotates the flat edge of the wafer to a preset angle and stops by the first rotating platform, and then the first lifting column rises to lift the wafer to complete the pre-alignment process of the wafer. As shown in (d), the first lifting column rises to the wafer transfer height and waits for the robotic arm to pick up the wafer.

[0137] S1002: Use the robotic arm to obtain the tray from the tray cassette and transport it to the second pre-alignment device for pre-alignment; the flat edge of the pre-aligned wafer and the flat edge of the pre-aligned tray have the same angle.

[0138] In the actual wafer picking process, the pre-alignment process of the tray is the same as that of the wafer. First, the tray cassette is opened by the tray loading port, and then the robotic arm obtains the tray from the tray cassette and transports it to the second pre-alignment device for pre-alignment. Specifically, Figure 12 is a schematic diagram of a tray pre-alignment process provided by an embodiment of the present application. Combining Figure 12As shown, the second lifting column receives the tray and places it on the second rotating platform. At this time, the center of the tray is not aligned with the center of the second rotating platform, as shown in (a). Then, the second rotating platform drives the tray to rotate. Similarly, based on photoelectric conversion, a voltage waveform similar to a sine wave can be formed during the rotation of the tray. The center point of the tray is calculated through the waveform and the direction of the flat edge (notch / flat) of the tray is determined. After determination, the eccentricity e is rotated to a direction parallel to the X-axis. Then, as shown in (b), the second lifting column rises and lifts the tray. Then, as shown in (c), the second lifting column moves a distance of the eccentricity e in the X-axis direction towards the center of the second rotating platform to achieve the alignment of the center of the tray. Finally, the second rotating platform drives the tray to rotate so that the four through holes on the tray correspond to the four second lifting columns, enabling the second lifting columns to pass through the through holes when rising without lifting the tray, thus completing the pre-alignment process of the tray. It should be noted that the flat edge angles of the pre-aligned wafer and the pre-aligned tray are the same, ensuring that the wafer and the tray can be aligned and combined.

[0139] S1003: Use the robotic arm to transport the pre-aligned wafer above the tray and place the wafer on the tray using the second pre-alignment device.

[0140] Figure 13 This is a flowchart of a combination method provided by an embodiment of the present application. Combining Figure 13 As shown, the second lifting column corresponds to the through hole of the tray, enabling the second lifting column to pass through the through hole when rising without lifting the tray, thus completing the pre-alignment process of the tray. As shown in (a), in the combination stage, the second lifting column rises and passes through the through hole of the tray to reach the wafer transfer height. As shown in (b), the robotic arm transports the pre-aligned wafer above the tray and places it on the second lifting column. It should be noted that at this time, the flat edge angles of the tray and the wafer are the same. As shown in (c), the second lifting column descends, dropping the wafer into the tray to complete the loading action of the wafer, and the wafer and the tray are combined.

[0141] S1004: Use the robotic arm to transport the tray loaded with the wafer to the process module and perform the process.

[0142] Figure 14 This is a schematic flowchart of a process for transporting a tray carrying a wafer to a process module provided by an embodiment of the present application. Combining Figure 14As shown in the figure, the second rotating platform drives the tray carrying the wafer to rotate, so that the through holes of the tray do not correspond to the second lifting columns (generally, the tray is rotated counterclockwise by 90°, so that the long side of the rectangle formed by connecting the through holes in sequence is perpendicular to the long side of the rectangle formed by connecting the second lifting columns as vertices in sequence). At this time, the second lifting columns rise, lift the tray carrying the wafer to the transfer height, and the robotic arm transports the tray loaded with the wafer to the process module and performs the process.

[0143] In summary, for an alignment method during wafer picking provided in an embodiment of the present application, first, a robotic arm is used to obtain a wafer from a wafer cassette and transport it to a first pre-alignment device for pre-alignment. Then, the robotic arm is used to obtain a tray from a tray cassette and transport it to a second pre-alignment device for pre-alignment. Among them, the flat edges of the pre-aligned wafer and the flat edges of the pre-aligned tray have the same angle. Then, the robotic arm transports the pre-aligned wafer above the tray, and the second pre-alignment device is used to place the wafer into the tray. Finally, the robotic arm transports the tray loaded with the wafer to the process module and performs the process. In this way, by pre-aligning the wafer and the tray respectively through two pre-alignment devices, the number of transports is reduced and the pre-alignment accuracy is improved.

[0144] Figure 15 is a flowchart of an alignment method during wafer placement provided in an embodiment of the present application. Combining Figure 15 As shown in the figure, an embodiment of the present application provides an alignment method during wafer placement, including:

[0145] S1501: Use a robotic arm to obtain the tray carrying the wafer after the process is completed from the process module and transport it to the second pre-alignment device;

[0146] S1502: Use the second pre-alignment device to pre-align the tray carrying the wafer;

[0147] S1503: Use a robotic arm to transport the wafer on the pre-aligned tray to the wafer cassette and transport the tray to the tray cassette.

[0148] In practical applications, the wafer needs to be placed after the process is completed. The robotic arm takes out the tray carrying the wafer from the process module and places it on the second lifting column at the transfer height lifted in the second pre-alignment device. Then, the second lifting column descends, and the tray is placed on the second rotating platform. The second rotating platform drives the tray to rotate and perform pre-alignment, and the pre-alignment method is the same as when taking the wafer. After the center alignment is completed, the second rotating platform drives the tray to continue rotating so that the through hole of the tray corresponds to the second lifting column. In this way, when the second lifting column rises, it can pass through the through hole to lift the wafer alone and transfer it to the robotic arm, enabling the robotic arm to carry the wafer back into the wafer cassette. Then the second lifting column descends, and the second rotating platform continues to drive the tray to rotate until the through hole of the tray does not correspond to the second lifting column. At this time, the second lifting column rises again to lift the tray to the transfer height, and the robotic arm carries the tray back to the tray cassette, completing the wafer placement operation.

[0149] In summary, the embodiment of the present application provides an alignment method during the wafer placement process. First, the robotic arm obtains the tray carrying the wafer after the process is completed from the process module and transports it to the second pre-alignment device. Then, the second pre-alignment device is used to pre-align the tray carrying the wafer. Finally, the robotic arm transports the wafer on the pre-aligned tray to the wafer cassette and transports the tray to the tray cassette. In this way, the wafer placement relies on a single pre-alignment device, improving the wafer placement efficiency.

[0150] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present application. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An alignment system, characterized in that: include: Equipment front-end module and process module; The equipment front-end module includes a robotic arm, a first pre-alignment device and a second pre-alignment device; When taking out wafers, the robot arm is used to move the wafers from the wafer box to the first pre-alignment device, and move the tray from the tray box to the second pre-alignment device; The first pre-alignment device is used to pre-align the wafer; The second pre-alignment device is used to pre-align the tray; The robotic arm is further used to carry the pre-aligned wafer to the top of the pre-aligned tray, and the second pre-alignment device places the wafer into the tray; The robotic arm is further used to transport the tray carrying the wafers to the process module; the process module is used to receive the tray and perform subsequent processes on the wafers carried by the tray.

2. The system according to claim 1, wherein: The first pre-alignment device includes: a first linear sensor, a first lifting assembly and a first rotating platform; The first lifting assembly is used to dock with the robotic arm when it is raised, and receive the wafer carried by the robotic arm; The first lifting assembly is used to dock with the first rotating platform when lowered to place the wafer on the first rotating platform; The first rotating platform is used to fix the wafer and drive the wafer to rotate; The first linear sensor includes a first receiving end and a first transmitting end, wherein the first transmitting end is used to generate a first linear light directed toward the first receiving end; the first receiving end is used to receive the first linear light blocked by the rotating wafer and determine the center of the wafer based on photoelectric conversion; The first lifting assembly is further used to move the wafer after centering, and to align the wafer with the first rotating platform; The first rotating platform is further used to perform flat edge alignment on the center-aligned wafer.

3. The system according to claim 2, characterized in that The first linear light has a specific length and is partially blocked by the wafer fixed on the first rotating platform, and the first linear light is perpendicular to both the wafer and the first receiving end.

4. The system according to claim 2, wherein: The first lifting assembly includes at least three first lifting columns, and the first lifting columns are sequentially connected as vertices to form a polygon.

5. The system according to claim 4, characterized in that All of the first lifting columns are connected to the same movement control assembly; The movement control assembly is used to control each of the first lifting columns to move in the same direction.

6. The system according to claim 1, wherein: The second pre-alignment device includes: a second linear sensor, a second lifting assembly and a second rotating platform; During the pre-alignment process of the pallet, the second lifting assembly is used to dock with the robotic arm when it is raised, and receive the pallet carried by the robotic arm; The second lifting assembly is used to dock with the second rotating platform when lowered, so as to place the pallet on the second rotating platform; The second rotating platform is used to fix the tray and drive the tray to rotate; The second linear sensor includes a second receiving end and a second transmitting end, the second transmitting end is used to generate a second linear light emitted to the second receiving end; the second receiving end is used to receive the second linear light blocked by the rotating tray and determine the center of the tray based on photoelectric conversion; The second lifting assembly is further used to move the pallet after centering, and to align the pallet with the second rotating platform; The second rotating platform is also used to align the center-aligned tray with its flat edges.

7. The system according to claim 6, characterized in that The second linear light has a specific length and is partially blocked by the tray fixed on the second rotating platform, and the second linear light is perpendicular to both the tray and the second receiving end.

8. The system according to claim 6, wherein: The second lifting assembly includes at least three second lifting columns, and the second lifting columns are sequentially connected as vertices to form a polygon.

9. The system according to claim 8, characterized in that All of the second lifting columns are connected to the same movement control assembly; The movement control assembly is used to control each of the second lifting columns to move in the same direction.

10. The system according to claim 6, wherein: The upper surface of the tray is provided with a groove for placing the wafer, and the depth of the groove is the same as the thickness of the wafer; The inner surface of the tray is provided with a limiting block corresponding to the flat edge of the wafer, which is used to limit the rotation of the wafer relative to the tray.

11. The system according to claim 8, wherein: The tray is provided with through holes whose number matches the number of the second lifting columns, and the pattern formed by sequentially connecting the through holes is consistent with the polygon formed by sequentially connecting the second lifting columns as vertices; When the pallet is placed on the second rotating platform by the second lifting column, a figure formed by sequentially connecting the through holes and a polygon formed by sequentially connecting the second lifting columns as vertices form a specific angle; When the pre-alignment of the pallet is completed, the second rotating platform rotates the pallet counterclockwise by a specific angle to align the through hole of the pallet with the second lifting column, so that the second lifting column can pass through the through hole when it is raised without lifting the pallet.

12. The system according to claim 11, wherein: The number of the second lifting assemblies and the number of the through holes are both four; The figure formed by sequentially connecting the four through holes and the polygon formed by sequentially connecting the four second lifting columns as vertices are both rectangles; when the tray is placed on the second rotating platform by the second lifting columns, the long sides of the rectangle formed by sequentially connecting the through holes and the long sides of the rectangle formed by sequentially connecting the second lifting columns as vertices are perpendicular to each other; When the pre-alignment of the pallet is completed, the second rotating platform rotates the pallet 90° counterclockwise to align the through hole of the pallet with the second lifting column, so that the second lifting column can pass through the through hole when it is raised without lifting the pallet.

13. The system according to claim 12, wherein: After the tray is rotated 90° counterclockwise, the flat edge of the tray is consistent with the flat edge angle of the pre-aligned wafer.

14. The system according to claim 1, wherein: When placing wafers, the robotic arm is used to move the tray carrying the wafers from the process module to the second pre-alignment device; The second pre-alignment device is used to pre-align the tray carrying the wafer; The robotic arm is further used to transport the wafers on the pre-aligned tray to the wafer box, and to transport the tray to the tray box.

15. An alignment method during film taking, characterized in that: The method is applied to the alignment system according to any one of claims 1 to 14, and the method comprises: Using a robotic arm to obtain wafers from a wafer box and transport them to a first pre-alignment device for pre-alignment; Using a robotic arm to obtain a tray from a tray box and transporting it to a second pre-alignment device for pre-alignment; the flat edge of the wafer after pre-alignment is consistent with the flat edge of the tray after pre-alignment; Using a robotic arm to move the pre-aligned wafer to above the tray, and using the second pre-alignment device to place the wafer into the tray; The tray loaded with the wafers is transported to a process module by a robotic arm for subsequent processing.

16. A method for alignment during film placement, characterized in that: The method is applied to the alignment system according to any one of claims 1 to 14, and the method comprises: Using a robotic arm to obtain the tray carrying the wafers after the process is completed from the process module and transport it to the second pre-alignment device; Pre-aligning the tray carrying the wafer using a second pre-alignment device; The wafers on the pre-aligned tray are transported to a wafer box by a robotic arm, and the tray is transported to a tray box.

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