Ion implanter batch target changing mechanism and batch target changing method

Abstract

The present invention discloses a batch target changing mechanism and a batch target changing method for an ion implanter. The batch target changing mechanism includes a target table, a storage chamber, a first conveying assembly, and a steering conveying mechanism. The target table is rotatably mounted in the batch target chamber. The target table is evenly provided with a plurality of target disks along the circumference. The disk surface of the target disk is perpendicular to the target table. Several wafers are horizontally placed in the storage chamber. The steering conveying mechanism includes a wafer changing disk and a second conveying assembly. The first conveying assembly is used to realize wafer transfer between the storage chamber and the wafer changing disk. The wafer changing disk is used to clamp the wafers and realize switching between the horizontal and vertical states of the wafers. The second conveying assembly is used to realize wafer transfer between the wafer changing disk and the target disk. The batch target changing mechanism of the present invention can greatly simplify the structure of the target disk in the entire target chamber, avoid complex movements in the target chamber, thereby reducing the particle size in the target chamber and improving the product yield. The batch target changing method of the present invention has simple steps, convenient operation, and smooth and efficient wafer change.

Description

Technical Field

[0001] The invention belongs to the technical field of semiconductor manufacturing equipment, and in particular relates to a batch target changing mechanism and a batch target changing method for an ion implanter. Background Art

[0002] As one of the key doping equipment in the manufacture of semiconductor devices, the ion implanter can precisely control the implantation angle and dosage, doping concentration and depth, improve the integration, yield and life of the circuit, and reduce costs and power consumption. Existing ion implanters use a robot to directly deliver the wafers to the target disk in the target chamber when changing targets in batches. The wafers in the storage chamber are placed horizontally due to storage requirements, but during the ion implantation process, the wafers need to be placed vertically to face the ion beam. The wafer handling robot has certain limitations and can only carry out wafer handling with three degrees of freedom: up and down, front and back, and horizontal rotation, and cannot flip the wafer. The existing solution is to separately set a rotating structure and a fixed-angle locking structure on each target position, and set corresponding drive and control mechanisms to realize the automatic flipping of each target disk relative to the target position to drive the flipping of the wafer on the target disk. Specifically, during wafer loading, a robot moves the wafer into the target chamber. The target tray in the target chamber is switched from the injection position to the wafer placement position and locked. After the wafer is placed, the target tray is switched from the wafer placement position to the injection position and locked. During wafer unloading, the locking mechanism is first opened, the target tray is switched from the injection position to the wafer placement position and locked, and then the robot removes the wafer. Because the batch target chamber has multiple target positions, each target position requires clamping, flipping, locking, driving, and control functions, making the target position structure of the entire target chamber complex. The inventors of this application discovered in practical research that the complex movement of the multiple target positions in the batch target chamber is very likely to produce metal particles and other contaminants, which can have an adverse effect on the process and reduce product yield. At the same time, due to the influence of assembly accuracy and processing accuracy, the existing wafer exchange mechanism has poor movement smoothness and high transmission friction, making it even more difficult to meet high particle size requirements. However, the semiconductor ion implantation process has increasingly stringent requirements for wafer particle size and target chamber cleanliness. Reducing the transmission particle size is an issue that cannot be ignored. To solve the particle size problem, it is necessary to simplify the target position structure in the target chamber and improve the movement smoothness and reliability of the structure. Therefore, there is an urgent need for a set of auxiliary transport mechanisms to achieve film transmission while effectively simplifying the structure of the target position in the target room. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide an ion implanter target batch changing mechanism and target batch changing method with simple structure, stable movement and high reliability in view of the deficiencies in the prior art.

[0004] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0005] An ion implanter batch target changing mechanism includes a target table, a wafer storage chamber, a first conveying assembly and a steering conveying mechanism. The target table is rotatably mounted in the target batch chamber. The target table is evenly provided with a plurality of target disks along the circumference. The disk surfaces of the target disks are perpendicular to the target table. Several wafers are horizontally placed in the wafer storage chamber. The steering conveying mechanism includes a wafer changing disk and a second conveying assembly. The first conveying assembly is used to realize wafer transfer between the wafer storage chamber and the wafer changing disk. The wafer changing disk is used to clamp wafers and realize switching between horizontal and vertical states of wafers. The second conveying assembly is used to realize wafer transfer between the wafer changing disk and the target disk.

[0006] As a further improvement of the present invention, the second transmission assembly includes a swing arm and a translation assembly, the film changing disc can be mounted on the free end of the swing arm so as to be flipped up and down, the fixed end of the swing arm is located on the translation assembly, the swing arm and the translation assembly are used to make the film changing disc reach the film changing handover position, the film changing handover position is the point where the circular motion trajectory of the center of the film changing disc is tangent to the circular motion trajectory of the center of the target disc, and the film changing disc to be changed is concentric with the target disc to be changed.

[0007] As a further improvement of the present invention, the free end of the swing arm is provided with a rotating assembly and a locking assembly, the film changing plate is mounted on the free end of the swing arm through the rotating assembly, and the locking assembly is used to lock the angle of the film changing plate when it needs to be fixed.

[0008] As a further improvement of the present invention, the target plate is a mechanical chuck or an electrostatic chuck.

[0009] As a further improvement of the present invention, the disc changing disc is a mechanical chuck.

[0010] As a further improvement of the present invention, the first conveying component is a robot, and the robot is installed in the film storage chamber.

[0011] As a general technical concept, the present invention also provides a method for batch target replacement based on the above-mentioned ion implanter batch target replacement mechanism, comprising the following steps:

[0012] S1. Wafer loading and replacement before ion implantation process:

[0013] S1.1. The first transfer assembly removes the wafers from the storage chamber and places them horizontally on the wafer exchange tray.

[0014] S1.2, flip the wafer tray to switch the wafer from a horizontal state to a vertical state;

[0015] S1.3. The second transfer assembly transfers the vertical wafer to the target plate;

[0016] S1.4. Switch the wafer tray from the vertical position to the horizontal position, and at the same time, coordinate with the rotation of the target stage, and repeat steps S1.1 to S1.3 until the target tray to be loaded with the wafer is loaded into the target chamber;

[0017] S2. Unloading and replacing the wafer after ion implantation process:

[0018] S2.1. The second transfer assembly transfers the processed wafer from the vertical target plate to the vertical wafer change plate.

[0019] S2.2, flip the wafer tray to a horizontal position, so that the wafer after processing switches from a vertical state to a horizontal state;

[0020] S2.3. The first transfer assembly transfers the processed wafers on the wafer exchange tray to the wafer storage chamber;

[0021] S2.4. Switch the wafer exchange plate from the horizontal position to the vertical position, and at the same time, coordinate with the rotation of the target stage, and repeat steps S2.1 to S2.3 until the target plate of the wafer to be unloaded after the process in the target chamber is unloaded.

[0022] Compared with the prior art, the advantages of the present invention are:

[0023] (1) In view of the problem that each target plate in the current batch target chamber not only needs to clamp the wafer, but also needs to be flipped at a certain angle to cooperate with the robot to transfer the wafer, which leads to the problem that the structure in the batch target chamber is cumbersome, the movement is complex, and metal particles are easily generated, the present invention provides an ion implanter batch target changing mechanism, which realizes the flipping of the wafer outside the target chamber by arranging a changing plate that can clamp and flip the wafer outside the target chamber, and then uses a second transfer component to realize the wafer transfer between the changing plate and the target plate, thereby eliminating the need to set a rotation, locking, driving and control structure for each target plate, and only needs to set a target plate that can vertically clamp the wafer at each target position to realize wafer changing, which can greatly simplify the structure of the target position and target plate in the entire target chamber, avoid complex movement in the target chamber, and thus greatly reduce the particle size in the target chamber, improve product yield, and improve movement reliability while maintaining the original wafer transfer efficiency.

[0024] (2) In the target changing mechanism of the ion implanter of the present invention, the steering transmission mechanism composed of the wafer changing plate, the swing arm and the translation assembly is mainly based on the movement of the same horizontal plane. The movement is smooth and reliable during the whole wafer changing process. The wafer changing plate is driven by the swing arm to swing in an arc between the wafer picking and placing position of the first transmission assembly and the wafer changing handover position. When the circular motion trajectory of the wafer changing plate center is tangent to the target plate center and the wafer changing plate and the target plate are concentric, it is the wafer changing handover position. This position is important and unique. By setting the wafer changing handover position in advance and changing the wafer according to this position, it can be ensured that the wafers between the wafer changing plate and the target plate are accurately and smoothly handed over.

[0025] (3) The batch target replacement method of the present invention has simple steps, convenient operation, and stable and efficient replacement. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a schematic diagram of the structural principle of the target batch changing mechanism of the ion implanter in Example 1 of the present invention.

[0027] Legend: 1. Target stage; 11. Target plate; 2. Wafer storage chamber; 3. First transport assembly; 4. Wafer; 5. Wafer exchange plate; 6. Second transport assembly; 61. Swing arm; 62. Translation assembly. DETAILED DESCRIPTION

[0028] The present invention will be further described below in conjunction with the accompanying drawings and specific preferred embodiments, but the scope of protection of the present invention is not limited thereby.

[0029] Example 1

[0030] Figure 1 The present invention shows a specific embodiment of the batch target wafer changing mechanism of the ion implanter, which includes a target table 1, a wafer storage chamber 2, a first conveying assembly 3 and a steering conveying mechanism. The target table 1 is rotatably installed in the batch target chamber. The target table 1 is evenly provided with multiple target disks 11 along the circumference. The disk surface of the target disk 11 is perpendicular to the target table 1. Several wafers 4 are horizontally placed in the wafer storage chamber 2. The steering conveying mechanism includes a wafer changing disk 5 and a second conveying assembly 6. The first conveying assembly 3 is used to realize the transfer of wafers 4 between the wafer storage chamber 2 and the wafer changing disk 5. The wafer changing disk 5 is used to clamp the wafer 4 and realize the switching of the wafer 4 between the horizontal state and the vertical state. The second conveying assembly 6 is used to realize the transfer of wafers 4 between the wafer changing disk 5 and the target disk 11. In this embodiment, a wafer changing plate 5 capable of clamping and flipping the wafer 4 is provided outside the target chamber to achieve flipping of the wafer 4 inside the target chamber, and a second conveying assembly 6 is used to transfer the wafer 4 between the wafer changing plate 5 and the target plate 11. Therefore, there is no need to provide each target plate 11 with a rotation, locking, driving and control structure. Only a target plate 11 capable of vertically clamping the wafer 4 is required at each target position to achieve wafer changing. This can greatly simplify the structure of the target positions and target plates 11 in the entire target chamber, avoid complex movements in the target chamber, and thus greatly reduce the particle size in the target chamber.

[0031] When loading and changing wafers in a batch target, the first conveyor assembly 3 (such as a robot) places the wafers 4 in the wafer storage chamber 2 horizontally on the wafer change tray 5. The wafer change tray 5 clamps the wafers 4 and flips them from a horizontal position to a vertical position. The second conveyor assembly 6 then conveys the vertical wafers 4 to the vertical target tray 11 for clamping. The wafer change tray 5 flips to a horizontal position for the next wafer loading. When unloading and changing wafers in a batch target, the second conveyor assembly 6 conveys the vertical post-process wafers from the vertical target tray 11 to the vertical wafer change tray 5. The wafer change tray 5 flips to a horizontal position. The first conveyor assembly 3 transfers the post-process wafers on the wafer change tray 5 to the wafer storage chamber 2. The wafer change tray 5 flips to a vertical position for the next wafer unloading.

[0032] As a further improvement, in this embodiment, the second conveying assembly 6 includes a swing arm 61 and a translation assembly 62. The film changing tray 5 is mounted on the free end of the swing arm 61 so as to be flipped up and down. The fixed end of the swing arm 61 is located on the translation assembly 62. The swing arm 61 and the translation assembly 62 are used to make the film changing tray 5 reach the film changing handover position. The film changing handover position is where the circular motion trajectory of the center of the film changing tray 5 is tangent to the circular motion trajectory of the center of the target tray 11, and the film changing tray 5 to be changed is concentric with the target tray 11 to be changed. The film changing tray 5 is driven by the swing arm 61 to the film taking and placing position ( Figure 1 A position shown) and the film change handover position ( Figure 1 The wafer change handover position is defined as the position where the wafer 4 is transferred between the wafer change tray 5 and the target tray 11. The wafer change handover position is defined as the position where the center of the wafer change tray 5 is tangent to the circular motion trajectory of the center of the target tray 11 and the wafer change tray 5 and the target tray 11 are concentric. This position is important and unique. By presetting the wafer change handover position and performing wafer changes according to this position, it is possible to ensure that the wafer 4 is transferred accurately and smoothly between the wafer change tray 5 and the target tray 11. The steering and conveying mechanism of this embodiment, consisting of the wafer change tray 5, the swing arm 61, and the translation assembly 62, is primarily based on movement in the same horizontal plane. This ensures smooth movement and high reliability throughout the wafer change process.

[0033] It can be understood that the steering conveyor mechanism composed of the wafer exchange tray 5, the swing arm 61, and the translation assembly 62 is equivalent to a handling robot with four degrees of freedom. Since the wafers 4 in the wafer storage chamber 2 are placed horizontally, the wafers 4 on the manipulator are also oriented horizontally, while the wafers 4 on the target plate 11 in the target chamber are oriented vertically (with the crystal plane facing the direction of beam injection). The two directions are perpendicular to each other. The steering conveyor mechanism of this embodiment can not only clamp the wafers 4, but also drive the wafers 4 to rotate 90 degrees to switch the wafers 4 to a vertical position, then enter the target chamber by swinging horizontally a certain angle. Finally, the translation assembly 62 causes the wafer exchange tray 5 to move linearly back and forth to the wafer exchange handover position, handing the vertical wafer 4 to the vertical target plate 11. In this embodiment, the wafer exchange tray 5 is a mechanical chuck, and the target plate 11 is a mechanical chuck or an electrostatic chuck. Wafer loading and exchange can be completed by simply clamping the wafer 4 brought by the wafer exchange tray 5 through the target plate 11. This can greatly simplify the movement structure of the target plate 11 in the target chamber and improve the cleanliness of the target chamber.

[0034] Of course, in other embodiments, the second conveying component 6 may also adopt other conveying structures, as long as the purpose of the present invention can be achieved, such as using a horizontally rotating turntable or annular turntable in conjunction with a robot: a plurality of flippable film changing discs 5 are evenly arranged on the annular turntable, and a robot is fixed at the center of the annular turntable. The film changing disc 5 is first switched to a vertical position, and the annular turntable drives the film changing disc 5 to rotate, and the target table 1 drives the target disc 11 to rotate. When the line connecting the center of the film changing disc 5 and the center of the target disc 11 overlaps with the line connecting the center of the annular turntable and the center of the target table 1, the wafer 4 can be clamped and translated by a robot with up and down and front and back freedom. However, compared with the present embodiment in which the film changing disc 5 and the target disc 11 are directly connected, the above-mentioned conveying structure has one more robot handover, is not as simple in structure as the present embodiment, and is not as smooth and reliable in operation as the present embodiment.

[0035] As a further improvement, in this embodiment, a rotating assembly and a locking assembly are provided at the free end of the swing arm 61. The wafer change tray 5 is mounted on the free end of the swing arm 61 via the rotating assembly, and the locking assembly is used to lock the angle of the wafer change tray 5 when it needs to be fixed. In this embodiment, the cooperation of the rotating assembly and the locking assembly allows for precise and smooth switching of the wafer change tray 5 and locking of the fixed angle. This prevents angular deviation of the wafer 4 during the swinging of the swing arm 61, which could affect the smooth transfer between the wafer change tray 5 and the target tray 11, further improving the smoothness of the steering transfer.

[0036] The manipulator is installed in the film storage chamber 2. The rotating assembly and the locking assembly can adopt the rotating structure of the existing technology, as long as it can realize the switching and locking of the horizontal and vertical positions of the film changing tray 5 in this embodiment. For example, two rotating shafts are provided on the outer periphery of the film changing tray 5 symmetrically about the center of the disk, and the two rotating shafts are respectively located on the extension lines of the same diameter of the film changing tray 5. A bracket is provided at the free end of the swing arm 61 to rotate with the top of the bracket. The rotation of the rotating shaft is controlled by the motor to drive the film changing tray 5 to switch from 0° to 90°.

[0037] Example 2

[0038] A method for batch target replacement of an ion implanter based on the batch target replacement mechanism of embodiment 1 comprises the following steps:

[0039] S1. Wafer loading and replacement before ion implantation process:

[0040] S1.1. The first conveyor assembly 3 removes the wafer 4 from the wafer storage chamber 2 and places it horizontally on the wafer exchange tray 5.

[0041] S1.2, flip the wafer tray 5 to switch the wafer 4 from a horizontal state to a vertical state;

[0042] S1.3, the second conveying assembly 6 conveys the vertical wafer 4 to the target plate 11;

[0043] S1.4, the wafer changing plate 5 is switched from the vertical position to the horizontal position, and the target stage 1 is rotated at the same time, and steps S1.1 to S1.3 are repeated until all the wafers 4 on the target plates 11 in the target chamber are loaded.

[0044] S2. Unloading and replacing the wafer after ion implantation process:

[0045] S2.1. The second transfer assembly 6 transfers the processed wafer from the vertical target plate 11 to the vertical wafer change plate 5.

[0046] S2.2, flip the wafer tray 5 to a horizontal position, so that the wafer is switched from a vertical state to a horizontal state after processing;

[0047] S2.3, the first conveying assembly 3 conveys the processed wafers on the wafer exchange tray 5 to the wafer storage chamber 2;

[0048] S2.4, the wafer changing plate 5 is switched from the horizontal position to the vertical position, and the target table 1 is rotated in conjunction with the target changing plate 5, and steps S2.1 to S2.3 are repeated until all the processed wafers on the target plates 11 in the target chamber are unloaded.

[0049] Specifically, before the ion implantation process, wafers are loaded: the robot in the wafer storage chamber 2 moves the wafer 4 to the wafer exchange plate 5, places the wafer 4 horizontally and clamps it on the wafer exchange plate 5. The steering conveyor mechanism has four degrees of freedom, which respectively realizes the tilt rotation, angle swing, front and back translation and wafer 4 clamping through the rotating assembly, the swing arm 61, the translation assembly 62 and the wafer exchange plate 5. Finally, the wafer 4 is moved into the target chamber and is handed over to the target plate 11 of the target chamber at a specific handover position to complete a single wafer loading and changing; in conjunction with the rotation movement of the target stage 1 in the target chamber, the wafer changing mechanism goes back and forth for multiple times to complete all the wafer loading and changing of the target plate of the target chamber batch. After the ion implantation process, wafers are unloaded: the target plate 11 of the wafer that needs to be taken out after the process is rotated to the wafer exchange handover position in turn by the target stage 1, and is taken out in turn by the steering conveyor mechanism and moved away by the robot. The batch target changing method of this embodiment has simple steps, convenient operation, and smooth and efficient wafer changing.

[0050] Although the present invention is disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can, without departing from the spirit and technical solutions of the present invention, use the methods and technical contents disclosed above to make many possible changes and modifications to the technical solutions of the present invention, or modify them into equivalent embodiments with equivalent changes. Therefore, any simple modification, equivalent replacement, equivalent change and modification made to the above embodiments based on the technical spirit of the present invention without departing from the content of the technical solutions of the present invention, shall still fall within the scope of protection of the technical solutions of the present invention.

Claims

1. A target batch changing mechanism for an ion implanter, characterized in that: The invention comprises a target platform (1), a wafer storage chamber (2), a first conveying assembly (3) and a steering conveying mechanism, wherein the target platform (1) is rotatably mounted in the target batch chamber, the target platform (1) is evenly provided with a plurality of target disks (11) along the circumference, the disk surface of the target disk (11) being perpendicular to the target platform (1), a plurality of wafers (4) being horizontally placed in the wafer storage chamber (2), the steering conveying mechanism comprising a wafer changing disk (5) and a second conveying assembly (6), the first conveying assembly (3) being used for realizing the wafer (4) being conveyed between the wafer storage chamber (2) and the wafer changing disk (5), the wafer changing disk (5) being used for clamping the wafer (4) and realizing the switching of the wafer (4) between the horizontal state and the vertical state, and the second conveying assembly (6) being used for realizing the wafer (4) being conveyed between the wafer changing disk (5) and the target disk (11).

2. The ion implanter target batch changing mechanism according to claim 1, characterized in that: The second transmission assembly (6) comprises a swing arm (61) and a translation assembly (62); the film changing disc (5) is mounted on the free end of the swing arm (61) in a flippable manner; the fixed end of the swing arm (61) is located on the translation assembly (62); the swing arm (61) and the translation assembly (62) are used to enable the film changing disc (5) to reach a film changing handover position; the film changing handover position is a position where the circular motion trajectory of the center of the film changing disc (5) is tangent to the circular motion trajectory of the center of the target disc (11); and the film changing disc (5) to be changed is concentric with the target disc (11) to be changed.

3. The ion implanter target batch changing mechanism according to claim 2, characterized in that: The free end of the swing arm (61) is provided with a rotating assembly and a locking assembly. The film changing disc (5) is mounted on the free end of the swing arm (61) via the rotating assembly. The locking assembly is used to lock the angle of the film changing disc (5) when it needs to be fixed.

4. The target batch changing mechanism for an ion implanter according to any one of claims 1 to 3, characterized in that: The target disk (11) is a mechanical chuck or an electrostatic chuck.

5. The target batch changing mechanism for an ion implanter according to any one of claims 1 to 3, characterized in that: The disc changing disc (5) is a mechanical chuck.

6. The target batch changing mechanism for an ion implanter according to any one of claims 1 to 3, characterized in that: The first conveying component (3) is a robot, and the robot is installed in the film storage chamber (2).

7. A method for batch target replacement of an ion implanter based on the batch target replacement mechanism according to any one of claims 1 to 6, characterized in that: The following steps are involved: S1. Wafer loading and replacement before ion implantation process: S1.

1. The first transfer assembly (3) takes out the wafer (4) from the wafer storage chamber (2) and places it horizontally on the wafer exchange tray (5); S1.2, the wafer changing plate (5) is turned over to switch the wafer (4) from a horizontal state to a vertical state; S1.3, the second transfer assembly (6) transfers the vertical wafer (4) to the target plate (11); S1.4, the wafer changing plate (5) is switched from the vertical position to the horizontal position, and at the same time, in conjunction with the rotation of the target stage (1), steps S1.1 to S1.3 are repeated until the target plate (11) to be loaded with the wafer (4) in the target chamber is completely loaded; S2. Unloading and replacing the wafer after ion implantation process: S2.1, the second transfer assembly (6) transfers the processed wafer from the vertical target plate (11) to the vertical wafer exchange plate (5); S2.2, flipping the wafer tray (5) to a horizontal position, so that the wafer after processing is switched from a vertical state to a horizontal state; S2.3, the first transfer assembly (3) transfers the processed wafers on the wafer exchange tray (5) to the wafer storage chamber (2); S2.4, the wafer exchange plate (5) is switched from the horizontal position to the vertical position, and simultaneously in conjunction with the rotational movement of the target table (1), steps S2.1 to S2.3 are repeated until the target plate (11) of the wafer to be unloaded after the process in the target chamber is completely unloaded.

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