Fully Automated Wafer Appearance Inspection System

Abstract

The present invention discloses a fully automatic wafer appearance inspection system, comprising a wafer box unpacking and conveying machine, a wafer pick-up and unpacking manipulator, a wafer position calibration mechanism, a wafer flipping mechanism, and a microscope detection mechanism; the wafer box unpacking and conveying machine is used to open a wafer transfer box, the wafer pick-up and unpacking manipulator is used to carry wafers, the wafer position calibration mechanism is used to determine the center position of the wafer and rotate it to a specified angle; the wafer flipping mechanism is used to flip the wafer to facilitate inspection of its back side, and the microscope detection mechanism is used to inspect the surface of the wafer. The system can automatically transfer the wafer to a microscope for observation to avoid damage caused by manual handling; it can also visually inspect the surface and back side of the wafer; the transmission process adopts a linear motion to avoid the wafer being thrown out. It is suitable for use in semiconductor factories and wafer testing factories.

Description

Technical Field

[0001] The present invention relates to the technical field of electronic detection, and in particular to a wafer appearance inspection system. Background Art

[0002] Wafer refers to the silicon wafer used to make silicon semiconductor circuits. Its original material is silicon. High-purity polysilicon is dissolved and mixed with silicon crystal seeds, and then slowly pulled out to form cylindrical single crystal silicon. After grinding, polishing and slicing, the silicon crystal rod is formed into a silicon wafer, also known as a wafer. At present, domestic wafer production lines are mainly 8-inch and 12-inch.

[0003] Manufacturers often need to inspect the quality of wafers during delivery or receipt. Wafer boxes are usually stored in FOUPs and need to be taken out one by one for inspection. During the wafer turnover, the center position and direction of the wafer will shift at a small angle. In addition, the back of the wafer needs to be inspected. The existing inspection system cannot meet the above inspection requirements. Summary of the invention

[0004] The technical problem to be solved by the present invention is to solve the above-mentioned existing deficiencies and provide a wafer automatic detection system.

[0005] In order to solve the above-mentioned existing deficiencies, the technical solution adopted by the present invention is: a fully automatic wafer appearance inspection system, including a wafer box unpacking and conveying machine, a wafer loading and unloading robot, a wafer position calibration mechanism, a wafer flipping mechanism and a microscope detection mechanism; the wafer box unpacking and conveying machine is used to open the wafer transfer box, the wafer loading and unloading robot is used to carry the wafer, the wafer position calibration mechanism is used to determine the center position of the wafer and rotate it to a specified angle; the wafer flipping mechanism is used to flip the wafer to facilitate inspection of its back side, and the microscope detection mechanism inspects the surface of the wafer.

[0006] Furthermore, the wafer box unpacking and transporting machine includes a base for placing the wafer box; a fixed plate and a baffle are arranged on the side of the base, the fixed plate cooperates with the outer shell of the wafer box, the baffle is fitted with the fixed plate, and the baffle can move up and down relative to the fixed plate, the front end cover of the wafer box can pass through the fixed plate and abut against the baffle, two door opening modules and two horizontal positioning pins are arranged on the baffle, each door opening module includes a rotatable latch rod, the front end of the latch rod can be extended into the wafer box to unlock the wafer box, a linkage mechanism is arranged between the two latch rods, and the latch rods are synchronously rotated through the linkage mechanism, the horizontal positioning pin can be extended into the wafer box to position it in the vertical direction, a suction cup is also provided on the horizontal positioning pin, the suction cup can be fitted with the wafer box, and a negative pressure exhaust port is arranged on the horizontal positioning pin.

[0007] Furthermore, there are two wafer box unpacking and transporting machines, each corresponding to a wafer box, one of which is used for unloading materials and the other is used for receiving materials.

[0008] Furthermore, it includes a rotatable suction cup, a mechanical arm, a scanning device, a main control module and a placement table; the scanning device is used to scan the edge position and the notch position of the wafer; the suction cup can be raised and lowered, and during the rising process, the wafer can be lifted from the placement table, and when it is lowered, the wafer can be placed on the placement table, and during the rotation process, the wafer can be driven to rotate; the main control module calculates the offset between the center position of the wafer and the center of the suction cup according to the edges of multiple wafers, and the mechanical arm moves the wafer according to the offset; the scanning range of the scanning device is a straight line, and the straight line is located in the radial direction of the suction cup, and the scanning device records the edge position of the wafer passing through the scanning range, and when the scanned edge position is at the maximum distance from the center of the suction cup, the maximum value at this time is set to d, and at this time the center of the wafer and the scanning range are on the same straight line, the offset is dr, r is the radius of the wafer, and the mechanical arm moves the wafer dr along the straight line; when the center of the wafer coincides with the center of the suction cup, the scanning device scans the position of the notch, and the suction cup drives the wafer to rotate so that the notch rotates to the specified position.

[0009] Furthermore, the wafer flipping mechanism includes two clamping arms for clamping the wafer, and is characterized in that: it also includes a slide rail and a turntable, the ends of the clamping arms are arranged on the slide rail and can slide along it, the ends of the two clamping arms located on the slide rail are respectively hinged to a connecting plate, the other end of the connecting plate is hinged to the turntable, and the turntable is connected to the motor shaft and driven to rotate; when the two clamping arms are clamped, the hinge axis of the connecting plate and the turntable is in the same plane as the motor axis, and the plane is parallel to the slide rail, and the two ends of any connecting plate are located on both sides of the motor axis.

[0010] Furthermore, the end of the connecting piece connected to the turntable is semicircular; the connecting line of the two ends of the connecting piece intersects the axis of the motor perpendicularly.

[0011] Furthermore, a plurality of clamping blocks are arranged on the clamping arm, and grooves are arranged on the surfaces of the clamping blocks, and the grooves match with the outer edges of the wafers.

[0012] Furthermore, the wafer flipping mechanism also includes a sensor for sensing whether there is a wafer between the clamping arms.

[0013] From the above technical solution, it can be seen that the present invention has the following advantages: by observing and comparing the pinhole position and the probe position, it is possible to quickly determine whether the probe is tilted or bent, and then make corrections. And by replacing the sheet, corrections can be made to different types of needle cards. The design of the support plate can relieve operator fatigue and is suitable for long-term work.

[0014] From the above technical scheme, it can be seen that the present invention has the following advantages: the wafer can be automatically transferred to the microscope for observation, avoiding damage caused by manual handling; the surface and back of the wafer can also be visually inspected; the transmission process adopts a linear motion to avoid the wafer being thrown out. It is suitable for use in semiconductor factories and wafer testing factories. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a structural schematic diagram of the present invention;

[0016] Figure 2 It is a schematic diagram of the structure of the wafer box unpacking and transporting machine in the present invention;

[0017] Figure 3 It is a schematic diagram of the back structure of the wafer box unpacking and transporting machine of the present invention;

[0018] Figure 4 It is a structural schematic diagram of a wafer position calibration mechanism;

[0019] Figure 5 It is a structural schematic diagram of a wafer flipping mechanism;

[0020] Figure 6 It is a structural schematic diagram of the wafer flipping mechanism. DETAILED DESCRIPTION

[0021] The specific implementation modes of the present invention are described in detail below with reference to the accompanying drawings.

[0022] like Figure 1 As shown, the fully automatic wafer appearance inspection system of the present invention includes a wafer box unpacking and conveying machine 1, a wafer loading and unloading robot 2, a wafer position calibration mechanism 3, a wafer flipping mechanism 4 and a microscope detection mechanism; the wafer box unpacking and conveying machine is used to open the wafer transfer box, the wafer loading and unloading robot is used to carry the wafer, the wafer position calibration mechanism is used to determine the center position of the wafer and rotate it to a specified angle; the wafer flipping mechanism is used to flip the wafer to facilitate inspection of the back side thereof, and the microscope detection mechanism is used to inspect the surface of the wafer.

[0023] The specific structure of the wafer box unpacking and transporting machine 1 is as follows: Figure 2 and Figure 3As shown, it includes a frame 17 and a base 16, the base 16 is used to place the wafer box; a fixed plate 11 and a baffle 12 are arranged on the side of the base, the baffle 12 is attached to the fixed plate 11, and the baffle 12 can move up and down relative to the fixed plate. The up and down movement of the baffle 12 can be achieved by a screw module or a cylinder. The front end cover of the wafer box can pass through the fixed plate and abut against the baffle 12. Two door opening modules and two horizontal positioning pins 18 are arranged on the baffle. Each door opening module includes a rotatable latch rod 13. The front end of the latch rod 13 can be extended into the wafer box to unlock the wafer box. A linkage mechanism is arranged between the two latch rods 13. The latch rods can realize synchronous rotation through the linkage mechanism. The horizontal positioning pin 18 can be extended into the wafer box to position it in the vertical direction. A suction cup 19 is also provided on the horizontal positioning pin. The suction cup 19 can fit with the wafer box. After opening the wafer box, the suction cup is used to adsorb the opened end cover. A negative pressure exhaust port is arranged on the horizontal positioning pin to discharge the air.

[0024] The base is also provided with a plurality of vertical positioning pins 15, which can extend into the bottom of the wafer box to position it horizontally. The vertical positioning pins can not only play a positioning role, but also an identification role. Only when the pin holes at the bottom of the wafer box correspond to the positions of the positioning pins on the base, the wafer box can be placed on the base. There is a hook 14 on the base, which is driven by a motor to move horizontally. When the wafer box is placed, the hook moves horizontally and extends into the bottom of the wafer box to fix it.

[0025] The linkage mechanism includes a crossbar 110 and a cylinder 112. A connecting block 111 is hinged at each end of the crossbar 110. The latch rods 13 are respectively arranged on the connecting blocks. The latch rods 3 pass through the baffle. The connecting block rotates to drive the latch rods to rotate. The cylinder 112 is used to push the crossbar 110 to translate. In order to push the crossbar with the cylinder, a vertical connecting block is arranged under the crossbar. The connecting block can be pushed by a horizontal cylinder. The connecting block drives the crossbar to translate, thereby driving the two connecting blocks to rotate, and then rotating the latch rod.

[0026] The positioning pin is used to achieve multi-directional positioning, and the hook fixes the box body. The end cover can be opened using the interlocking mechanism of the latch rod, and then the end cover can be adsorbed by the suction cup. The baffle can then be moved down to separate the end cover from the box body, thereby realizing automated unpacking.

[0027] The wafer loading and unloading manipulator includes two parallel rotating arms, namely the first rotating arm and the second rotating arm. One end of the first rotating arm is mounted on the base and can be rotated, and the other end is connected to the end of the second rotating arm. A turntable is set at the other end of the second rotating arm, and a wafer suction cup and an infrared sensor are set on the turntable. The rotating shafts of the first rotating arm, the second rotating arm and the turntable are all set in parallel. The multi-axis manipulator can be raised and lowered. There are two infrared sensors, which are located at the same height. The infrared sensor scans the wafers in the material box to determine whether there are materials stored in each slot. Setting two infrared sensors can reduce misjudgments and missed judgments.

[0028] The wafer loading and unloading robot is a relatively mature technical means in this field and will not be described in detail here.

[0029] Wafer position calibration mechanism 3 Figure 4 As shown, it includes a rotatable suction cup 32, a robotic arm 31 (the robotic arm can be a rotating arm of a material picking and placing robot 2), a scanning device 33, a main control module and a placement table 34; the scanning device is used to scan the edge position and the notch position of the wafer, using infrared scanning, and the scanning range of the scanning device is a straight line, and the straight line is located radially of the suction cup 32.

[0030] The suction cup 32 can absorb the wafer and can be raised and lowered. During the rising process, the wafer can be lifted from the placement table 34, and when it is lowered, the wafer can fall on the placement table. During the rotation process, the wafer can be driven to rotate.

[0031] The main control module processes the data. Specifically, the scanning device records the edge position of the wafer within the scanning range. When the scanned edge position is at the maximum distance from the center of the suction cup, the maximum value is set to d. At this time, the center of the wafer and the scanning range are on the same straight line, and the offset is dr. r is the radius of the wafer. The robotic arm or suction cup moves the wafer dr along the straight line. When the center of the wafer coincides with the center of the suction cup, the scanning device scans the position of the notch, and the suction cup drives the wafer to rotate so that the notch rotates to the specified position.

[0032] The wafer position calibration mechanism can quickly identify the center position of the wafer and quickly perform offset correction. In addition, it can scan the notch and perform angle correction. The wafer position calibration mechanism is also provided with a scanning device for scanning the label on the wafer to identify its identity.

[0033] Wafer flip mechanism Figure 6 and Figure 5As shown, it includes two clamping arms 41 for clamping wafers. The clamping arms are in an arc shape, and a plurality of clamping blocks 42 are arranged on them. The surface of the clamping blocks is provided with grooves, and the grooves match the outer edge of the wafer. The clamping blocks 42 can be made of softer materials to reduce the wear of the wafer. The use of clamping blocks can reduce direct contact with the wafer and reduce the contaminated area. A sensor 43 can be arranged above the clamping arms to sense whether there is a wafer between the clamping arms.

[0034] The wafer flipping mechanism also includes a chassis 49, on which a slide rail 44 and a turntable 48 are arranged. The ends of the clamping arms are arranged on the slide rail 44 and can slide along it. The ends of the two clamping arms located on the slide rail are respectively hinged with a connecting piece 47, and the connecting piece is "S"-shaped or "C"-shaped. The other end of the connecting piece 47 is hinged with the turntable 48, and the rotating shaft of the turntable connected to the motor 410 is driven to rotate by it; when the two clamping arms are clamped, the hinge axis of the connecting piece and the turntable is located in the same plane as the motor axis, and the plane is parallel to the slide rail, and the two ends of any connecting piece are located on both sides of the motor axis, and the connecting line of the two ends of the connecting piece is perpendicular to the motor axis. At this time, even if the motor is powered off, because the hinge point of the connecting piece, the connection point of the turntable and the motor are located on the same straight line, and the straight line is parallel to the slide rail, the turntable is only subjected to the force in the direction parallel to the slide rail, and the turntable will not rotate, so the clamping arm can remain locked and the wafer will not fall off. In order to facilitate the rotation of the connecting piece, the end portion of the connecting piece connected to the turntable can be set to be semicircular. The two connecting pieces rotate without affecting each other.

[0035] In addition, the present invention is also provided with two position sensors 45, and a sensing sheet 46 is also provided at the end of the clamp arm located on the turntable, and the position sensor is used to detect the sensing sheet, thereby determining the moving position of the clamp arm, and accurately controlling the clamping force to prevent the wafer from being damaged.

[0036] The microscope inspection mechanism is used to inspect the wafer, and a switch button is provided on it, which is mainly used for switching between visual inspection and microscopic inspection.

[0037] The present invention also includes a dust-free housing, in which all functional modules are located, clean gas is introduced into the top of the housing, and the gas flows downward from the top. This design is used to place the wafer in a dust-free environment and reduce pollution to the wafer.

[0038] The working process of the present invention is as follows: the round box unpacking carrier is a dual-station structure, namely site A and site B. When sites A and B are both in use, site A is used to place a material box loaded with wafers, and site B is used to place an empty material box. The types of material boxes at the two sites must be consistent; when one of sites A or B is in use, just place the loaded material box at one of the sites.

[0039] The wafer pick-up and place robot 2 takes the wafer from the wafer and puts it into the wafer position calibration mechanism 3 to calibrate the center position and rotate it to a required angle. In addition, the wafer is scanned and its ID is read.

[0040] After calibration, the wafer pick-up and placement robot moves it to the flipping mechanism and flips the wafer 180°. Then, the pick-up and placement robot 2 carries it to the microscope inspection mechanism to complete the back side inspection.

Claims

1. A fully automatic wafer appearance inspection system, characterized by: It includes a wafer box unpacking and conveying machine, a wafer picking and placing robot, a wafer position calibration mechanism, a wafer flipping mechanism and a microscope detection mechanism; the wafer box unpacking and conveying machine is used to open the wafer transfer box, the wafer picking and placing robot is used to carry the wafer, the wafer position calibration mechanism is used to determine the center position of the wafer and rotate it to a specified angle; the wafer flipping mechanism is used to flip the wafer to facilitate the inspection of its back side, and the microscope detection mechanism is used to inspect the surface of the wafer; The wafer box unpacking and transporting machine comprises a base, and the base is used to place the wafer box; A fixing plate and a baffle are arranged on the side of the base, the fixing plate cooperates with the outer shell of the wafer box, the baffle is fitted with the fixing plate, and the baffle can move up and down relative to the fixing plate, the front end cover of the wafer box can pass through the fixing plate and abut against the baffle, two door opening modules and two horizontal positioning pins are arranged on the baffle, each door opening module includes a rotatable latch rod, the front end of the latch rod can be extended into the wafer box to unlock the wafer box, a linkage mechanism is arranged between the two latch rods, and the latch rods are synchronously rotated through the linkage mechanism, the horizontal positioning pin can be extended into the wafer box to position it in the vertical direction, a suction cup is also arranged on the horizontal positioning pin, the suction cup can be fitted with the wafer box, and a negative pressure exhaust port is arranged on the horizontal positioning pin; There are two wafer box unpacking and transporting machines, one corresponding to each wafer box, one for unloading and the other for receiving; The invention comprises a rotatable suction cup, a mechanical arm, a scanning device, a main control module and a placement table; the scanning device is used to scan the edge position and the notch position of the wafer; the suction cup can be raised and lowered, and the wafer can be lifted from the placement table during the rising process, and can be dropped on the placement table when it is lowered, and can drive the wafer to rotate during the rotation process; the main control module calculates the offset between the center position of the wafer and the center of the suction cup according to the edges of multiple wafers, and the mechanical arm moves the wafer according to the offset; the scanning range of the scanning device is a straight line, and the straight line is located in the radial direction of the suction cup, and the scanning device records the edge position of the wafer passing through the scanning range, and when the scanned edge position is at the maximum distance from the center of the suction cup, the maximum value at this time is set to d, and at this time the center of the wafer and the scanning range are on the same straight line, the offset is dr, r is the radius of the wafer, and the mechanical arm moves the wafer dr along the straight line direction; when the center of the wafer coincides with the center of the suction cup, the scanning device scans the position of the notch, and the suction cup drives the wafer to rotate so that the notch rotates to the specified position; The wafer flipping mechanism includes two clamping arms for clamping the wafer, a slide rail and a turntable. The ends of the clamping arms are arranged on the slide rail and can slide along the slide rail. The ends of the two clamping arms located on the slide rail are respectively hinged with a connecting piece, and the connecting piece is S-shaped or C-shaped. The other end of the connecting piece is hinged with the turntable, and the turntable is connected to the motor shaft and driven to rotate by it. When the two clamping arms are clamped, the hinge axis of the connecting piece and the turntable and the motor axis are located in the same plane, and the plane is parallel to the slide rail, and the two ends of any connecting piece are located on both sides of the motor axis, and the connecting line of the two ends of the connecting piece intersects the motor axis perpendicularly. At this time, even if the motor is powered off, since the hinge point of the connecting piece and the connection point of the turntable and the motor are located on the same straight line, and the straight line is parallel to the slide rail, the turntable is only subjected to the force in the direction parallel to the slide rail, and the turntable will not rotate, so the clamping arms can remain locked and the wafer will not fall off; The end portion of the connecting piece connected to the turntable is semicircular, and the connecting line of the two ends of the connecting piece intersects the axis of the motor perpendicularly.

2. The fully automatic wafer appearance inspection system according to claim 1, characterized in that: A plurality of clamping blocks are arranged on the clamping arm, and grooves are arranged on the surfaces of the clamping blocks, and the grooves match the outer edges of the wafers.

3. The fully automatic wafer appearance inspection system according to claim 2, characterized in that: The wafer flipping mechanism also includes a sensor for sensing whether there is a wafer between the clamping arms.

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