Automatic positioning device and measuring equipment

Abstract

The invention belongs to the field of electron microscope measurement, and relates to an automatic positioning device and measuring equipment, the automatic positioning device comprises a cavity, a positioning mechanism is arranged in the cavity, and a driving mechanism is mounted on the cavity; the positioning mechanism at least provides two positioning points to abut against a workpiece. The driving mechanism is used for driving the workpiece to move towards the positioning mechanism and is matched with the positioning mechanism to position the workpiece; the driving mechanism comprises a driver and a spring piece, the main body part of the driver is located outside the cavity, the driving end of the driver penetrates into the cavity, the spring piece which is opened in a bent shape is installed at the driving end, the spring piece is connected with the detection circuit, and when the driver pushes the spring piece to a preset position, the spring piece and the positioning mechanism jointly clamp a workpiece. The spring piece is pressed to deform, the open end of the spring piece is closed to conduct the detection circuit, meanwhile, accurate positioning and positioning detection of the workpiece are achieved, the positioning precision is high, and work is efficient. The device is suitable for detection of transparent and non-transparent workpieces and has a wide application range.

Description

Technical Field

[0001] The invention belongs to the technical field of electron microscope measurement, and in particular relates to an automatic positioning device and a measuring device. Background Art

[0002] Wafers are silicon sheets used to manufacture silicon semiconductor circuits (chips), with many square chip units distributed on their surface. As the demand for chips continues to grow, the demand for critical dimension measurement equipment (CD-SEM) used to detect chips has also risen. Critical dimension measurement equipment uses a scanning electron microscope (SEM) to detect chips, and the scanning electron microscope can only operate in a high vacuum environment. Therefore, the chip must be transferred from the atmospheric environment to the scanning electron microscope in a high vacuum environment. The current solution is to use a semiconductor equipment front end module (EFEM) to remove the wafer from the wafer box and transfer it to the transfer chamber of the critical dimension measurement equipment. When the transfer chamber is evacuated to a predetermined vacuum level, the isolation valve on the chamber where the vacuum robot is placed can be opened, and the vacuum robot can take the wafer and transfer it to the scanning electron microscope for inspection.

[0003] First, the existing solutions mainly focus on improving the repeatability of the EFEM manipulator and the vacuum manipulator to improve the positioning accuracy of the wafer under the scanning electron microscope. The key to this accuracy lies in the accuracy of the wafer transfer between the two manipulators. At the same time, in order to accurately measure this accuracy, at least three digital laser sensors are usually used for simultaneous measurement. The digital laser sensor emits a small light spot, and the receiver detects the corresponding change in light flux. When the wafer blocks part of the light spot of these digital laser sensors, the value of the light flux changes, thereby determining the position of the wafer. Then, it is determined whether each wafer transferred through the EFEM falls within the set accuracy range. This laser sensor measurement method is only applicable to non-transparent wafers, and has great limitations for transparent wafers. In addition, the debugging personnel need to spend a lot of time adjusting the position and verticality of the digital laser sensor. In addition, the wafer positioning and measurement of the existing solution are carried out step by step, with a large number of parts and a complex structure, and the detection efficiency needs to be improved.

[0004] Second, the existing wafer positioning device is only suitable for measuring wafers of a single size. When it is necessary to change to measure wafers of different sizes, the original parts must be disassembled and replaced, and then re-debugged, which is time-consuming and laborious.

[0005] Third, during the wafer transfer process, the transfer chamber needs to frequently establish and release the vacuum: after the high vacuum is established, the vacuum manipulator needs to complete the action of taking and placing the wafer in the transfer chamber before the vacuum can be released; after taking the wafer, the wafer must be sent to a scanning electron microscope for inspection, and it can be put back into the transfer chamber after the inspection is completed. Between taking and placing the wafer, the transfer chamber needs to maintain a high vacuum state. Although the time to release the vacuum is short, it takes a long time to establish a high vacuum state. In order to improve the wafer transfer efficiency of key dimension measurement equipment, the transfer chamber is usually designed to be smaller, which can shorten the time required to establish a high vacuum state. However, in the narrow transfer chamber, the heat generated by pushing the wafer is difficult to dissipate in a vacuum state. This requires a positioning device with a simple structure and good heat dissipation performance to position the wafer. Summary of the invention

[0006] In view of the defects of the prior art, one of the purposes of the present invention is to provide an automatic positioning device applicable to transparent and non-transparent wafers, to ensure the positioning accuracy of the wafer in the cavity, and to complete the positioning detection work while positioning, so that the work is efficient and convenient.

[0007] The automatic positioning device includes: It comprises a cavity, a positioning mechanism is arranged in the cavity, and a driving mechanism is installed on the cavity; The positioning mechanism provides at least two positioning points for abutting and positioning the workpiece; The driving mechanism is used to drive the workpiece to move in the direction of the positioning mechanism and cooperate with the positioning mechanism to position the workpiece; Among them, the driving mechanism includes a driver and a spring sheet, the main part of the driver is located outside the cavity, and its driving end penetrates into the cavity. The driving end is installed with a spring sheet that is bent and opened, and the spring sheet is connected to the detection circuit. When the driver pushes the spring sheet to a predetermined position, the spring sheet and the positioning mechanism jointly clamp the workpiece, the spring sheet is deformed under pressure, and its open end is closed to make the detection circuit conductive, thereby realizing precise positioning and positioning detection of the workpiece.

[0008] The present invention can roughly position the workpiece near the positioning mechanism, and through the action of the driving mechanism, the spring sheet is moved toward the positioning mechanism in the cavity, and then the spring sheet is used to push the workpiece toward the positioning mechanism to achieve accurate clamping and positioning of the workpiece. In this process, the spring sheet that was originally in an open state is closed due to the squeezing of the workpiece. Since the spring sheet will disconnect the detection circuit in the open state, and the detection circuit will be turned on after closing, the present invention can not only accurately position the workpiece, but also synchronously detect whether the positioning is successful. This solution replaces the existing solution of using at least three digital laser sensors to simultaneously measure the positioning accuracy of the workpiece, and is not only suitable for transparent workpieces, but also for the detection of opaque workpieces, thereby having a wider range of applications. In addition, because the heat dissipation of the driving mechanism in a vacuum state will be greatly affected, the main body of the driver is placed outside the cavity to avoid heat dissipation difficulties.

[0009] Preferably, the spring sheet comprises a fixed portion and a movable portion which are arranged substantially opposite to each other in the vertical direction, the fixed portion is mounted on the driving end of the driver, and corresponding conductive columns are respectively arranged on the inner sides of the fixed portion and the movable portion; When the spring sheet is in an open state, the conductive posts do not contact each other. When the movable portion is pressed by the workpiece, the conductive posts contact each other and conduct, thereby closing the detection circuit.

[0010] The present invention provides corresponding conductive columns on the inner sides of the fixed part and the movable part of the spring sheet. When the movable part that opens outward is pushed toward the fixed part by the workpiece and deformed, the two conductive columns contact each other, so that the detection circuit is turned on. At this time, the fixed part and the movable part are basically in a parallel state, ensuring that the movable part can directly apply pressure to the workpiece, thereby maintaining the accuracy of the workpiece positioning. At the same time, due to the small volume of the cavity, the conductive column reduces the deformation amplitude of the movable part of the spring sheet, making it suitable for compact cavity space. Compared with the flexible spring sheet, the contact between the conductive columns is more stable, further ensuring the reliability of the detection result.

[0011] Preferably, the outer side of the movable portion is covered with a top block for abutting against a workpiece; The driving end of the driver is further configured with a support block for supporting the movable part and the top block below the spring sheet, and the support block is an insulator.

[0012] The enhanced structure of the top block improves the holding force of the spring sheet on the workpiece, effectively preventing the contact area between the spring sheet and the workpiece from being concave and deformed due to pressure, thereby improving the positioning accuracy and detection accuracy.

[0013] The support block continuously supports the movable part and the top block to prevent the movable part from sagging and deforming under the influence of gravity, thereby avoiding the misalignment of the two conductive columns and ensuring that the detection circuit can be smoothly turned on.

[0014] Furthermore, a slot body is provided in the support block, and a ball spring pin is installed in the slot body; In the free state, the ball of the ball spring pin is tightly attached to the inner side of the movable part, preventing the movable part from approaching the fixed part; when the movable part is squeezed by the workpiece, the ball is pressed downward by the movable part and retracted into the groove body, so that the two conductive columns are in contact.

[0015] When the driver pushes the spring sheet forward, the spring sheet may shake back and forth due to inertia and the flexible material of the spring sheet itself. This shaking may cause the two conductive pillars to accidentally contact each other, thereby erroneously turning on the detection circuit. In order to solve this problem, the present invention embeds a ball spring pin in the slot of the support block so that it is close to the inner side of the movable part, effectively preventing the movable part from approaching the fixed part, preventing the conductive pillar from accidentally touching, and thus significantly improving the accuracy of the detection. When the movable part is squeezed by the workpiece, the ball can be easily pressed into the slot, thereby causing the two conductive pillars to contact each other to complete the detection.

[0016] Preferably, the driver is a cylinder, a distance measuring plate is installed at the rear end of the piston rod of the cylinder, and a displacement sensor is fixed outside the cavity and arranged at a distance from the distance measuring plate. The displacement sensor determines the position of the piston rod by measuring the distance of the distance measuring plate, thereby determining the position of the spring sheet and detecting whether the cylinder has moved into place.

[0017] Preferably, the driver further specifically comprises a cylinder body, a connecting rod, a bellows and a cylinder spring, wherein the connecting rod and the piston rod are coaxially fixedly connected to the front and rear sides of the cylinder piston respectively, the spring sheet is installed at the front end of the connecting rod, and the distance measuring plate is installed at the rear end of the piston rod; The cylinder spring is sleeved on the piston rod. When the cylinder piston moves backward under the action of air pressure, the cylinder spring is compressed; when the cylinder spring is released from pressure, the piston and the connecting rod are pushed forward.

[0018] The connecting rod is fixedly connected to the piston rod, the distance measuring plate is installed at the rear end of the piston rod, and the spring sheet is installed at the front end of the connecting rod, so the distance measuring plate and the spring sheet can move synchronously. The displacement sensor is used to detect the moving distance of the distance measuring plate, which is equivalent to the moving distance of the spring sheet. In the cylinder body, the cylinder spring and the compressed air work together to push the piston rod forward and backward respectively, thereby realizing the extension and retraction of the spring sheet.

[0019] Preferably, the connecting rod is covered with a bellows, and a mounting block is provided in the vertical direction on one side of the connecting rod close to the cavity. The front and rear ends of the bellows are respectively sealed and connected to the mounting block and the outer wall of the cylinder body, so that the inside and outside of the bellows are airtightly isolated; a cylinder connecting tube is also airtightly connected between the cylinder body and the cavity, and the bellows is located in the cylinder connecting tube.

[0020] The bellows seals the connecting rod, which ensures the sealing performance of the connection between the cylinder connecting tube, the cylinder body, the connecting rod and the cavity, and enables it to flexibly expand and contract following the movement of the connecting rod.

[0021] The cavity is provided with a through hole connected to the inside of the cylinder connecting tube, the connecting rod passes through the through hole, and the mounting block of the connecting rod can move back and forth in the through hole. The bellows is inside the cylinder connecting tube, so that an airtight space is formed between the bellows and the cylinder connecting tube, the connecting rod, the cylinder body and the cavity.

[0022] Secondly, the present invention also solves the problem that the positioning mechanism cannot flexibly adapt to wafers of different sizes: At least two groups of the positioning mechanisms and a top block abut against the workpiece together. The positioning mechanism includes an adjusting base and a positioning column. The adjusting base is provided with a plurality of positioning holes for adapting to workpieces of different sizes. The positioning column is installed in one of the positioning holes. After the adjusting base is rotated to a set angle, it is fixed in the cavity by bolts so that the positioning column abuts against the workpiece.

[0023] The positioning column is used to abut against the workpiece, and preferably the top end of the positioning column is conical, so that the workpiece can fall smoothly near the positioning column.

[0024] The positioning mechanism abuts against the shoulder of the workpiece and cooperates with the top block on the spring sheet to form a triangular positioning layout, which improves the positioning stability of the workpiece. The adjustment base can be rotated in the cavity to a suitable angle so that the positioning column accurately abuts against the edge of the workpiece, and then the adjustment base is fixed with bolts. Multiple positioning holes on the adjustment base further improve the adaptability to workpieces of different sizes.

[0025] Thirdly, the present invention also solves the problem of heat dissipation in the cavity during the pushing process: A bearing mechanism for supporting the workpiece is arranged in the cavity, and the bearing mechanism includes a bearing column and a bearing ring. The bearing column is fixed on the inner wall of the cavity in the horizontal direction, and the front end of the bearing column is installed with a bearing ring that is in point contact with the bottom surface of the workpiece. Because the heat dissipation performance in a vacuum state will be significantly reduced, and the bearing ring of the present invention is in point contact with the bottom of the workpiece, the contact area is small, and because the workpiece will slide on the bearing ring during the positioning process, the heat generated by the friction between the two is reduced, which is more conducive to improving the heat dissipation problem caused by pushing the workpiece in a vacuum environment.

[0026] Another object of the present invention is to provide a measurement device, including a scanning electron microscope and a transfer chamber, wherein the transfer chamber is used to transfer a workpiece from an atmospheric environment to a scanning electron microscope in a high vacuum environment, and the transfer chamber includes the above-mentioned automatic positioning device. Through a semiconductor equipment front-end module (EFEM), a workpiece (such as a wafer taken out of a wafer box) is transferred to a transfer chamber of a critical dimension measurement device. The workpiece is placed on a carrying mechanism and roughly positioned by a positioning mechanism. Subsequently, the drive is started to gently push the workpiece to a set position to achieve precise positioning and positioning detection. When the vacuum degree in the transfer chamber reaches a predetermined level, the isolation valve on the chamber where the vacuum manipulator is placed will be opened. The vacuum manipulator then obtains the workpiece and transfers it to a scanning electron microscope for inspection.

[0027] The beneficial effects of the present invention are: 1. The present invention realizes accurate positioning of the workpiece through the coordinated work of the driver, spring sheet and positioning mechanism, reduces the repeated positioning accuracy requirements for the EFEM manipulator and the vacuum manipulator during the workpiece transfer process, and thus reduces the production cost. The above detection schemes are applicable to the detection of transparent and non-transparent workpieces, successfully overcoming the limitations of the traditional laser sensor detection scheme. In addition, the mutual cooperation of these mechanisms also realizes the function of detecting the positioning result while positioning the workpiece, simplifies the structure of the device, and improves the work efficiency.

[0028] 2. The driving mechanism of the present invention cooperates with the positioning mechanism, and the adjusting base can be rotated to a suitable angle in the cavity to make the positioning column accurately abut the edge of the workpiece, and then the adjusting base is fixed with bolts, which can be used to position workpieces of different sizes. The multiple positioning holes on the adjusting base further improve the adaptability to workpieces of different sizes, and save the cumbersome debugging steps when changing wafers.

[0029] 3. The main part of the driver of the present invention is located outside the cavity, which is conducive to heat dissipation and increasing the moving stroke. The bearing ring and the bottom of the workpiece are in point contact, with a small contact area, which reduces the heat generated by the friction between the two and is more conducive to improving the heat dissipation problem of the workpiece moving in the vacuum environment of the cavity. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings: Figure 1 It is a schematic diagram of the structure of the present invention; Figure 2 It is a schematic diagram of the structure of the present invention when positioning a circular workpiece; Figure 3 It is a structural schematic diagram of the driving mechanism and the bearing mechanism of the present invention; Figure 4 is a schematic diagram of a top view of a spring sheet in an open state in one embodiment of the present invention; Figure 5 is a schematic diagram of a top view of a spring sheet in a closed state in one embodiment of the present invention; Figure 6 It is a side view structural diagram of a ball spring pin abutting against a movable portion of a spring sheet in one embodiment of the present invention; Figure 7 It is another perspective structural schematic diagram of the present invention; Figure 8 It is a schematic diagram of a top view of the structure of an embodiment of the present invention; Fig. 9 yes Figure 8 Schematic cross-sectional view in the GG direction; Fig.10 It is a schematic diagram of the internal structure of the cylinder of the present invention; Fig.11 It is a partial schematic diagram of the airtight space at the connection between the cylinder and the cavity embodying the present invention; Fig.12 It is a schematic diagram of the positioning mechanism of the present invention.

[0031] The markings in the figure are: 1. Driving mechanism; 1-1. Cylinder; 1-11. Cylinder body; 1-12. Piston; 1-13. Air inlet; 1-14. Connecting rod; 1-15. Piston rod; 1-16. Cylinder spring; 1-17. Cylinder connecting tube; 1-18. Bellows; 1-19. Mounting block; 1-2. Displacement sensor; 1-3. Distance measuring plate; 1-4. Top block; 1-5. Spring sheet; 1-51. Fixed part; 1-52. Movable part; 1-53. Conductive column; 1-6. Bottom plate; 1-7. Support block; 1-71. Slot body; 1-8. Ball spring pin; 2. Positioning mechanism; 2-1. Positioning column; 2-2. Adjusting base; 2-3. Positioning hole; 3. Carrying mechanism; 3-1. Carrying ring; 3-2. Carrying column; 3-3. Carrying seat; 4. Cavity; 4-1. Through hole; 5. Airtight space; 6. Workpiece. DETAILED DESCRIPTION

[0032] The automatic positioning device is used to automatically and accurately position the workpiece in the cavity and detect the positioning result of the workpiece at the same time. The workpiece can be a sheet or plate-like structure such as a circle, a polygon, an ellipse, etc., and the present application does not limit its shape. In a specific embodiment, the workpiece is as follows Figure 2 and Fig. 9The wafer shown in . The cross-section of the cavity can also be circular, polygonal or other special-shaped structures, and this application does not limit it. In order to meet the needs of wafer scanning detection, the cavity in this embodiment is designed as a sealed structure (only part of the structure is shown in the figure to show the internal structure of the cavity). However, those skilled in the art can adjust the sealing of the cavity accordingly according to the specific needs of other application environments. The following will be explained by taking the automatic positioning device used to transfer the wafer from the atmospheric environment to the electron microscope transfer chamber as an example.

[0033] Example 1 like Figures 1 to 3 As shown, the automatic positioning device includes a cavity 4, a positioning mechanism 2 and a bearing mechanism 3 are arranged in the cavity 4, and a driving mechanism 1 is installed on the cavity 4. The positioning mechanism 2 provides at least two positioning points to abut the workpiece, specifically, two positioning columns 2-1 abut the opposite sides of the workpiece, preferably abut the two shoulders of the workpiece, and cooperate with the driving mechanism 1 to form a positioning layout similar to a triangle, thereby improving the positioning stability.

[0034] The driving mechanism 1 can drive the workpiece to move in the direction of the positioning mechanism 2, and cooperate with the positioning mechanism 2 to position the workpiece. Among them, the driving mechanism 1 includes a driver and a spring sheet 1-5. The driver can be a conventional driver such as an electromotive drive or a pneumatic drive. The driver in this embodiment uses a cylinder. The main body of the driver is located outside the cavity. Because the heat dissipation of the driving mechanism 1 under a vacuum state will be greatly affected, the main body of the driver is placed outside the cavity, and its stroke in the cavity is increased, and its driving end penetrates into the cavity. The driving end is installed with a spring sheet 1-5 that is bent and opened. The spring sheet 1-5 is connected to the detection circuit. The detection circuit known in the art at least includes a power supply and a resistor. If necessary, it can include an output element (including but not limited to a light prompter, a sound prompter, a display screen, an electric vibrator, etc.). The detection circuit is connected to the control unit of the electronic scanning microscope to send the detection result signal to the control unit.

[0035] The spring sheet 1-5 will disconnect the detection circuit in the open state; when the driver pushes the spring sheet 1-5 to the predetermined position, the spring sheet 1-5 and the positioning mechanism 2 jointly clamp the workpiece, the spring sheet 1-5 is deformed by pressure, and its open end is closed to make the detection circuit conductive, and the output element prompts that the workpiece is accurately positioned. Therefore, the present invention can not only accurately position the workpiece, but also synchronously detect whether the positioning is successful. This solution replaces the solution of using at least three digital laser sensors to simultaneously measure the positioning accuracy of the workpiece in the prior art, and is not only suitable for transparent workpieces, but also for the detection of opaque workpieces, thereby having a wider range of applications. It should be understood that "open end closure" in this article means that the open ends of the spring sheets 1-5 are in contact with each other and become closed.

[0036] In a specific embodiment, the spring sheet 1-5 includes a fixed portion 1-51 and a movable portion 1-52 which are arranged substantially opposite to each other in the vertical direction, and the fixed portion 1-51 is installed at the driving end of the driver. "Vertical" refers to the direction perpendicular to the paper surface, and "substantially arranged opposite to each other" means that the movable portion 1-52 is substantially opposite to the fixed portion 1-51, but the movable portion 1-52 is slightly opened outward after being bent, such as Figure 4 As shown, a small angle is formed between the fixing portion 1-51 and the conductive pillars 1-53 do not contact each other when the spring sheet 1-5 is in the open state. Figure 5 As shown, when the movable part 1-52 is squeezed by the workpiece, the conductive pillars 1-53 contact each other and become conductive, thus closing the detection circuit.

[0037] In a preferred embodiment, corresponding conductive columns 1-53 are respectively provided on the inner sides of the fixed portion 1-51 and the movable portion 1-52. In the present invention, corresponding conductive columns 1-53 are respectively provided on the inner sides of the fixed portion 1-51 and the movable portion 1-52 of the spring sheet 1-5. When the movable portion 1-52 opened outward is pushed toward the fixed portion 1-51 by the workpiece and deformed, the two conductive columns 1-53 contact each other, making the detection circuit conductive. Compared with the flexible spring sheet 1-5, the contact between the conductive columns 1-53 is more stable, further ensuring the reliability of the detection result; at this time, the fixed portion 1-51 and the movable portion 1-52 are basically in a parallel state, ensuring that the movable portion 1-52 can apply pressure to the workpiece, maintaining the accuracy of the workpiece positioning.

[0038] In a specific embodiment, the outer side of the movable portion 1-52 is covered with a top block 1-4 for abutting the workpiece. The reinforced structure of the top block 1-4 increases the holding force of the spring sheet 1-5 on the workpiece, effectively preventing the spring sheet 1-5 from being deformed due to pressure in the contact area with the workpiece, thereby improving the positioning accuracy and detection accuracy.

[0039] Example 2 like Figures 4 to 6 As shown, on the basis of Example 1, in order to improve the accuracy of repeated positioning / repeated detection of the spring sheet 1-5 and prevent the movable part from falling after long-term use, which causes the two conductive pillars 1-53 to fail to contact accurately, the driving end of the driver is further configured with a support block 1-7 for supporting the movable part 1-52 and the top block 1-4 below the spring sheet 1-5. The support block 1-7 is an insulator, the rear side of which is fixed below the fixed part 1-51 of the spring sheet 1-5, and the front side is in sliding contact with the movable part 1-52. The support block 1-7 continuously supports the movable part 1-52 and the top block 1-4 to prevent the movable part 1-52 from sagging and deforming under the influence of gravity, thereby avoiding the misalignment of the two conductive pillars 1-53 and ensuring that the detection circuit can be smoothly turned on.

[0040] When the driver pushes the spring sheet 1-5 forward, the spring sheet 1-5 may shake back and forth due to the inertial effect and the flexible material properties of the spring sheet 1-5, or when the elastic force of the spring sheet fails due to fatigue. This shaking may cause accidental contact between the two conductive pillars 1-53, thereby erroneously turning on the detection circuit. In order to solve this problem, in a preferred embodiment, the top surface of the support block 1-7 is provided with a concave groove body 1-71, and a ball spring pin 1-8 is installed in the groove body 1-71. In the free state, the ball of the ball spring pin 1-8 protrudes from the outside of the groove body 1-71 and is close to the inner side of the movable part 1-52, preventing the shaking movable part 1-52 from approaching the fixed part 1-51, thereby avoiding accidental contact between the two conductive pillars 1-53. When the movable part 1-52 is squeezed by the workpiece, the ball is pressed downward by the movable part 1-52 and retracted into the groove body 1-71, so that the two conductive pillars 1-53 are in contact with each other, and then the two conductive pillars 1-53 are in contact with each other to complete the detection work, which significantly improves the accuracy of the detection.

[0041] Example 3 In order to more accurately determine whether the movement distance of the spring sheet 1-5 is in place, based on the embodiment 1 or 2, a displacement sensor 1-2 is fixed outside the cavity and is spaced apart from the distance measuring plate 1-3. The present application does not limit the type of displacement sensor 1-2, which can be a linear displacement sensor 1-2 such as a laser rangefinder, a potentiometer displacement sensor 1-2, or an ultrasonic displacement sensor 1-2. The specific installation structure of the displacement sensor 1-2 is not limited, and it can be fixed on the same base plate 1-6 as the cylinder, or it can be installed separately. Figures 1 to 3 As shown, in a specific embodiment, the displacement sensor 1-2 is a laser rangefinder, which is located directly behind the distance measuring plate 1-3. The distance measuring plate 1-3 is installed at the tail end of the piston 1-12 rod of the cylinder. The displacement sensor 1-2 determines the position of the piston 1-12 rod by measuring the distance of the distance measuring plate 1-3, thereby determining the position of the spring sheet 1-5 and detecting whether the cylinder has moved into place.

[0042] like Figure 7-11As shown, the driver specifically includes a cylinder body 1-11, a connecting rod 1-14, a bellows 1-18, a cylinder spring 1-16 and a cylinder connecting tube 1-17. The cylinder connecting tube 1-17 is fixed to the outer wall of the cavity by screws, and the installation gap is sealed by a rubber ring to prevent air leakage. The other side of the cylinder connecting tube 1-17 is sealed and connected to the cylinder body 1-11. The piston 1-12 inside the cylinder body 1-11 is airtightly connected to the cylinder body 1-11 through a rubber ring. The connecting rod 1-14 and the piston 1-12 rod are coaxially fixedly connected to the front and rear sides of the cylinder piston 1-12 respectively, and the spring sheet 1-5 is installed at the front end of the connecting rod 1-14, and the distance measuring plate 1-3 is installed at the rear end of the piston 1-12 rod, so when the piston 1-12 moves forward and backward, the spring sheet 1-5 and the distance measuring plate 1-3 move synchronously. The displacement sensor 1-2 detects the moving distance of the distance measuring plate 1-3, so this distance is equivalent to the moving distance of the spring piece 1-5.

[0043] It should be understood that the airtight connection achieved by using a rubber ring in the present application can of course also be achieved by using other sealing materials known in the art, and the present application does not impose any limitation on this.

[0044] More specifically, the front end of the cylinder body 1-11 is provided with an air inlet 1-13, which is always connected to a high-pressure air source through a solenoid valve. Compressed air enters the cylinder body 1-11 through the air inlet 1-13, pushing the piston 1-12 to move backward, thereby moving the connecting rod 1-14 away from the workpiece. The air inlet 1-13 is connected to the atmosphere only when a thrust is required to be applied to the workpiece. In this embodiment, the solenoid valve of the air inlet is a three-way valve, the second port of which is connected to the air source through an air path, and the third port is directly connected to the atmosphere.

[0045] The cylinder spring 1-16 is sleeved on the piston 1-12 rod. When the cylinder piston 1-12 moves backward under the action of air pressure, the cylinder spring 1-16 is compressed. When the air inlet 1-13 valve is directly connected to the atmosphere through the solenoid valve, the cylinder spring 1-16 is released from pressure, pushing the piston 1-12 and the connecting rod 1-14 forward, thereby pushing the workpiece forward and realizing the extension and retraction of the spring sheet 1-5. Therefore, in the cylinder body 1-11, the cylinder spring 1-16 works in conjunction with the compressed air to push the piston 1-12 rod forward and backward respectively.

[0046] In one embodiment, please refer to Figures 9 to 11The connecting rod 1-14 is covered with a bellows 1-18, and a mounting block 1-19 is arranged in the vertical direction on one side of the connecting rod close to the cavity. The front and rear ends of the bellows 1-18 are respectively sealed to connect the mounting block 1-19 and the outer wall of the cylinder body 1-11, so that the inside and outside of the bellows 1-18 are airtightly isolated, and the bellows can be synchronously extended and retracted with the connecting rod; the cavity 4 is provided with a through hole 4-1 connected to the inside of the cylinder connecting tube 1-17, the connecting rod 1-14 passes through the through hole 4-1, and the mounting block 1-19 of the connecting rod can move forward and backward in the through hole. Since the bellows 1-18 is located in the cylinder connecting tube 1-17, an airtight space 5 is formed between the bellows 1-18 and the cylinder connecting tube 1-17, the connecting rod 1-14, the cylinder body 1-11, and the cavity. Therefore, the above-mentioned structures cooperate with each other to ensure the sealing performance of the connection between the connecting rod 1-14 and the cavity and the connection between the cylinder body 1-11, and enable it to flexibly expand and contract following the movement of the connecting rod 1-14.

[0047] Example 4 like Figure 1-2 and Fig.12 As shown, the present application comprises at least two groups of positioning mechanisms 2 and a top block 1-4 to abut against the positioning workpiece. In order to improve the adaptability and operational convenience of the positioning mechanism 2, the positioning mechanism 2 in this embodiment, based on the above embodiments, includes an adjustment base 2-2 and a positioning column 2-1. The adjustment base 2-2 is provided with a plurality of positioning holes 2-3 for adapting to workpieces of different sizes, and a positioning column 2-1 is installed in one of the positioning holes 2-3. Before use, the adjustment base 2-2 is first rotated according to the size of the workpiece (such as a wafer) until it is rotated to a set angle so that the positioning column 2-1 can just abut against the edge of the workpiece, and then the adjustment base 2-2 is locked and fixed in the cavity with bolts. A plurality of positioning holes 2-3 are provided on the adjustment base 2-2, and the positioning column 2-1 can be installed in one of the positioning holes 2-3 according to the workpieces of different sizes, thereby further improving the adaptability.

[0048] Preferably, the top end of the positioning post 2 - 1 is tapered so that the workpiece can slide smoothly along the tapered surface to the side of the positioning post 2 - 1 without being blocked by the positioning post 2 - 1 .

[0049] A bearing mechanism 3 for supporting the workpiece is arranged in the cavity, and the number of the bearing mechanisms 3 is at least three groups, preferably four groups, which are arranged opposite to each other at the front and rear sides of the cavity. Figure 3As shown, in order to further improve the heat dissipation problem in the cavity, the bearing mechanism 3 includes a bearing column 3-2 and a bearing ring 3-1. The bearing column 3-2 is fixed on the inner wall of the cavity in the horizontal direction. The front end of the bearing column 3-2 is installed with a bearing ring 3-1 that is in point contact with the bottom surface of the workpiece. In addition, a bearing seat 3-3 can be installed on the inner wall of the cavity to fix the bearing column 3-2 on the bearing seat 3-3. Because the heat dissipation performance in a vacuum state will be significantly reduced, and the bearing ring 3-1 of the present invention is in point contact with the bottom of the workpiece, the contact area is small, and because the workpiece will slide on the bearing ring 3-1 during the positioning process, the heat generated by the friction between the two is reduced, which is more conducive to improving the heat dissipation problem of pushing the workpiece in a vacuum environment.

[0050] An optional positioning method of the positioning mechanism of this embodiment is as follows: First, use a 12-inch wafer to determine the center position of all sizes of wafers. For example, first place the 12-inch wafer at the preset position, and then rotate the adjustment base so that the positioning column abuts the 12-inch wafer. Then fix the adjustment base, and the adjustment base will no longer change its position. At this time, the driver program can be adjusted so that the program records the driving process of the 12-inch wafer.

[0051] Then move the positioning column to the positioning hole of the 8-inch wafer, place the 8-inch wafer, and adjust the driver program again so that the program records the pushing process of the 8-inch wafer by the driver.

[0052] Then move the positioning column to the positioning hole of the 6-inch wafer, place the 6-inch wafer, and adjust the driver program again so that the program records the pushing process of the 6-inch wafer by the driver.

[0053] The above steps are used to determine the positioning points of wafers of different sizes and complete the program preset.

[0054] Example 5 This embodiment provides a measurement device, including a scanning electron microscope and a transfer chamber, the transfer chamber is used to transfer the workpiece from the atmospheric environment to under the scanning electron microscope in a high vacuum environment, and the transfer chamber includes the automatic positioning device in the above embodiment to achieve precise positioning and positioning detection.

[0055] The specific working process of the automatic positioning device is as follows: At the start stage, the connecting rod 1-14 of the cylinder 1-1 is in the retracted position, and the workpiece 6 (e.g., a wafer taken out of a wafer box) is transferred to the transfer chamber of the critical dimension measurement equipment through the semiconductor equipment front-end module (EFEM). The workpiece 6 is placed on the carrier mechanism 3, supported by the carrier ring 3-1, and preliminarily positioned by the positioning mechanism 2, that is, the workpiece 6 is slightly offset to one side of the driving mechanism 1, so as to avoid being interfered and supported by the positioning column 2-1.

[0056] Then the driver is started, the connecting rod 1-14 extends, and the workpiece is gently pushed to the preset position. With the assistance of the positioning column 2-1 on the opposite side, the workpiece squeezes the spring sheet 1-5, so that the two conductive columns 1-53 contact the conductive detection circuit.

[0057] When the displacement sensor 1-2 detects that the moving distance of the distance measuring plate 1-3 reaches a predetermined value and the detection circuit is turned on, it indicates that the workpiece 6 has been accurately moved to the specified position.

[0058] When the displacement sensor 1-2 detects that the moving distance of the ranging plate 1-3 reaches the predetermined value, but the detection circuit is not turned on, it indicates that the workpiece 6 has not moved to the specified position, and abnormal conditions such as the piece falling off or not being correctly transmitted may have occurred. At this time, the control unit will issue an alarm to prompt personnel to handle it.

[0059] When the displacement sensor 1-2 detects that the moving distance of the ranging plate 1-3 has not reached the predetermined value, and the detection circuit is turned on, indicating that an abnormal phenomenon of accidental touching of the two conductive pillars 1-53 has occurred during the movement (this abnormal phenomenon basically does not exist in Example 2-4), the control unit will issue an alarm 2 to prompt personnel to handle it.

[0060] After the positioning process is completed, the isolation valve on the chamber where the vacuum manipulator is placed will be opened only when the vacuum degree in the transfer chamber reaches a preset level. The vacuum manipulator then takes the workpiece 6 and transfers it to the scanning electron microscope for inspection.

[0061] The above are various embodiments of the present invention, one or more examples of which are shown in the accompanying drawings. In the description of the drawings, the same reference numerals refer to the same components. Generally, only the differences about the various embodiments are described. Each example is provided by way of explanation of the present invention and is not meant to limit the present invention. In addition, the features shown or described as part of one embodiment can be used on other embodiments or in combination with other embodiments to produce another embodiment, and it is intended that the description includes such modifications and variations.

Claims

1. An automatic positioning device, characterized in that: It comprises a cavity, a positioning mechanism is arranged in the cavity, and a driving mechanism is installed on the cavity; The positioning mechanism provides at least two positioning points for abutting the workpiece; The driving mechanism is used to drive the workpiece to move in the direction of the positioning mechanism and cooperate with the positioning mechanism to position the workpiece; Among them, the driving mechanism includes a driver and a spring sheet. The main part of the driver is located outside the cavity, and its driving end penetrates into the cavity. The driving end is equipped with a spring sheet that is bent and opened. The spring sheet is connected to the detection circuit. When the driver pushes the spring sheet to a predetermined position, the spring sheet and the positioning mechanism jointly clamp the workpiece, causing the spring sheet to be compressed and deformed, and the open end of the spring sheet is closed to turn on the detection circuit, thereby realizing precise positioning and positioning detection of the workpiece.

2. The automatic positioning device according to claim 1, characterized in that: The spring sheet comprises a fixed portion and a movable portion which are arranged substantially opposite to each other in the vertical direction, the fixed portion is mounted on the driving end of the driver, and corresponding conductive columns are respectively arranged on the inner sides of the fixed portion and the movable portion; When the spring sheet is in an open state, the conductive posts do not contact each other; when the movable portion is pressed by the workpiece to close the spring sheet, the conductive posts contact each other to turn on the detection circuit.

3. The automatic positioning device according to claim 2, characterized in that: The outer side of the movable part is covered with a top block for abutting against a workpiece; The driving end of the driver is further configured with a support block for supporting the movable part and the top block below the spring sheet, and the support block is an insulator.

4. The automatic positioning device according to claim 3, characterized in that: A slot body is provided in the support block, and a ball spring pin is installed in the slot body; In the free state, the ball of the ball spring pin is tightly attached to the inner side of the movable part, preventing the movable part from approaching the fixed part; when the movable part is squeezed by the workpiece, the ball is pressed downward by the movable part and retracted into the groove body, so that the two conductive columns are in contact.

5. The automatic positioning device according to claim 2, characterized in that: The driver is a cylinder, a distance measuring plate is installed at the rear end of the piston rod of the cylinder, a displacement sensor is fixed outside the cavity and spaced apart from the distance measuring plate, and the displacement sensor determines the position of the piston rod by measuring the distance of the distance measuring plate, thereby determining whether the spring sheet reaches the specified position.

6. The automatic positioning device according to claim 5, characterized in that: The driver also includes a cylinder body, a connecting rod, a bellows and a cylinder spring. The connecting rod and the piston rod are coaxially fixedly connected to the front and rear sides of the cylinder piston respectively to achieve synchronous movement. The front end of the connecting rod is equipped with the spring sheet, and the rear end of the piston rod is equipped with the distance measuring plate. The cylinder spring is sleeved on the piston rod. When the cylinder piston moves backward under the action of air pressure, the cylinder spring is compressed; when the cylinder spring is released from pressure, the piston and the connecting rod are pushed forward.

7. The automatic positioning device according to claim 6, characterized in that: The connecting rod is covered with a bellows, and a mounting block is arranged on one side of the connecting rod close to the cavity in the vertical direction. The front and rear ends of the bellows are respectively sealed and connected to the mounting block and the outer wall of the cylinder body, so that the inside and outside of the bellows are airtightly isolated; a cylinder connecting tube is also airtightly connected between the cylinder body and the cavity, and the bellows is located in the cylinder connecting tube; The cavity is provided with a through hole connected to the inside of the cylinder connecting tube, the connecting rod passes through the through hole, and the mounting block of the connecting rod moves back and forth in the through hole; the bellows is inside the cylinder connecting tube, so that an airtight space is formed between the bellows and the cylinder connecting tube, the connecting rod, the cylinder body, and the cavity.

8. The automatic positioning device according to claim 4, characterized in that: At least two groups of the positioning mechanisms and a top block abut against the workpiece together. The positioning mechanism includes an adjusting base and a positioning column. The adjusting base is provided with a plurality of positioning holes for adapting to workpieces of different sizes. The positioning column is installed in one of the positioning holes. After the adjusting base is rotated to a set angle, it is fixed in the cavity by bolts so that the positioning column abuts against the workpiece.

9. The automatic positioning device according to claim 4, characterized in that: A bearing mechanism for supporting the workpiece is arranged in the cavity, and the bearing mechanism comprises a bearing column and a bearing ring. The bearing column is fixed on the inner wall of the cavity along the horizontal direction, and a bearing ring is installed at the front end of the bearing column for point contact with the bottom surface of the workpiece.

10. A measuring device, characterized in that: It comprises a scanning electron microscope and a transfer chamber, wherein the transfer chamber is used to transfer a workpiece from an atmospheric environment to a scanning electron microscope in a high vacuum environment, and the transfer chamber comprises the automatic positioning device according to any one of claims 1-9.

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