Wafer state detection device

Abstract

The utility model relates to the technical field of wafer detection, in particular to a wafer state detection device. Comprising a lifting mechanism, the lifting mechanism is provided with a lifting body capable of performing lifting motion in the wafer stacking direction, and one side of the lifting mechanism is provided with a comb rack fixed in the lifting direction; the wafer state detection mechanism is connected with the lifting body, and the wafer state detection mechanism comprises correlation sensors which are arranged on a frame capable of moving in the horizontal direction, controllably located on the two sides of the wafer and used for outputting a first detection signal shaded by the wafer in the lifting process; and the wafer state sensor is arranged on the lifting body and outputs a second detection signal which is shaded by the comb rack during lifting. According to the utility model, the comb rack and the wafer state sensor are combined, and the correlation sensor is matched to construct a dual-detection mechanism, so that the influence of slight shaking of equipment on the detection result of the sensor can be compensated, and the detection result is more accurate.

Description

Technical Field

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

[0002] During the semiconductor manufacturing process, wafers, especially 12-inch wafers, require wafer boxes (FOUPs) when flowing between different processes. When the overhead crane (OHT) delivers the wafer box to the wafer box opening device of the corresponding process equipment, the wafer box opening device needs to open the wafer box and detect the status of the wafers in the wafer box. When the wafer status is normal, the wafer handling device will transport the wafers in the wafer box to the process table for corresponding processing; when the wafer status is abnormal, the wafer box opening device will alarm and stop the next action to prevent the abnormal wafer from damaging the wafer handling device and causing damage to the wafer, thereby invisibly increasing the operating cost of the equipment.

[0003] Existing wafer status detection mechanisms, such as the wafer status detection mechanism, detection method, and wafer transfer equipment disclosed in Chinese utility model patent application CN117174625A, have a detection device comprising a first sensor group and a second sensor group spaced apart in an upper and lower position. The emission light beams of the first sensor group and the second sensor group are parallel and the vertical distance is equal to the vertical distance between the placement surfaces of two adjacent wafer slots. The first sensor group and the second sensor group can move synchronously and uniformly along the Z axis to scan all wafers in the wafer box. The two wafer sensor groups are used to detect all states of the wafer, such as normal single wafer, no wafer, stacked wafers, left-right tilt, and front-back tilt. However, the two sensor groups of this mechanism are mounted on a frame with relatively weak rigidity, and the detection device will vibrate slightly when moving up and down. This vibration will affect the detection results of the sensors, and the accuracy of the detection results cannot be fully guaranteed. Utility Model Content

[0004] The purpose of this utility model is to provide a wafer status detection device to solve the above technical problems;

[0005] The technical problem solved by the present invention can be achieved by adopting the following technical solutions:

[0006] A wafer status detection device, comprising:

[0007] A lifting mechanism, wherein the lifting mechanism includes a lifting body that can move up and down along the direction of wafer stacking, and a comb tooth bar fixed along the lifting direction is provided on one side of the lifting mechanism;

[0008] A wafer status detection mechanism is connected to the lifting body, and the wafer status detection mechanism includes:

[0009] A through-beam sensor is provided on a frame movable in a horizontal direction and is controllably positioned on both sides of the wafer. The through-beam sensor is driven to move upward and downward by the lifting body, and the through-beam sensor outputs a first detection signal when light is blocked by the wafer during the lifting process.

[0010] The wafer status sensor is arranged on the lifting body, and the lifting body drives the wafer status sensor to move up and down. The wafer status sensor outputs a second detection signal that is shielded by the comb teeth during the lifting process.

[0011] Preferably, the comb tooth bar has comb teeth that match the number of the wafers, the spacing between the comb teeth corresponds to the spacing between the wafers, and each of the comb teeth includes a plurality of light-transmitting tooth grooves.

[0012] Preferably, the lifting mechanism further includes:

[0013] A single-axis robot is mounted on a fixed block of the single-axis robot. A liftable screw nut is provided inside the single-axis robot, and the lifter is connected to the screw nut.

[0014] A servo motor, wherein the output end of the servo motor is connected to a screw rod in the single-axis robot that cooperates with the screw rod nut, and the servo motor drives the screw rod to rotate and drive the screw rod nut to rise and fall.

[0015] Preferably, the lifting mechanism further includes:

[0016] a first slider, which is horizontally movable on the lifting body via a first guide rail slider, and the frame is connected to the first slider;

[0017] a first oscillating cylinder fixed to the lifting body via a first oscillating cylinder fixing block;

[0018] a first rocker connected to the output end of the first swing cylinder;

[0019] a first bearing disposed in a guide groove of the first slider, wherein the first swing cylinder is connected to the first bearing via the first rocker;

[0020] A first position sensor for detecting the position of the first slider is provided on the lifting body.

[0021] Preferably, it also includes,

[0022] A plurality of lifting position sensors are arranged on one side of the lifting mechanism along the lifting direction through a sensor fixing plate;

[0023] The induction sheet is arranged on the lifting body through a sensor fixing block.

[0024] Preferably, it also includes a fixed frame, on which is provided a carrying platform for placing a wafer box, the fixed frame is located above the carrying platform and is provided with a window, the opening of the wafer box is arranged corresponding to the window, and the wafer layer is placed in the wafer slot of the wafer box; the lifting mechanism is connected to the fixed frame and is located below the carrying platform.

[0025] Preferably, it further comprises a cover door for opening or closing the wafer box, which is arranged on a side of the fixed frame facing away from the wafer box and can be controllably moved close to or away from the window in a horizontal direction.

[0026] Preferably, the lifting mechanism further includes:

[0027] A second slider is disposed on the lifting body so as to be horizontally movable via a second guide rail slider, and a connecting rod is provided at the lower end of the opening door panel, the connecting rod being connected to the second slider;

[0028] a second oscillating cylinder fixed to the lifting body via a second oscillating cylinder fixing block;

[0029] a second rocker connected to the output end of the second swing cylinder;

[0030] a second bearing disposed in the guide groove of the second slider, wherein the second swing cylinder is connected to the second bearing via the second rocker;

[0031] A second position sensor for detecting the position of the second sliding block is provided on the lifting body.

[0032] Preferably, it further comprises a pneumatic mechanism, which is arranged at the bottom of the fixed frame, and the output end of the pneumatic mechanism is connected to the lifting mechanism.

[0033] Preferably, it further comprises an optical fiber amplifier connected to the incident sensor to receive the first detection signal.

[0034] The beneficial effects of the present invention are as follows: Due to the adoption of the above technical solution, the present invention combines the comb teeth and the wafer status sensor, and cooperates with the corresponding sensor to construct a dual detection mechanism, which can compensate for the influence of slight jitter of the equipment on the sensor detection results, making the detection results more accurate, and realizing the detection of the wafer status in the wafer box in a simple and economical way. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 This is a schematic structural diagram of a wafer status detection device in an embodiment of the present utility model;

[0036] Figure 2 This is a schematic diagram of the back structure of the wafer status detection device in an embodiment of the present utility model;

[0037] Figure 3 This is a schematic diagram of the connection between the lifting mechanism and the wafer status detection mechanism in an embodiment of the present utility model;

[0038] Figure 4 This is a structural diagram of the lifting mechanism in the embodiment of the utility model

[0039] Figure 5 This is a front view of the connection between the lifting mechanism and the wafer status detection mechanism in the embodiment of the present utility model;

[0040] Figure 6 for Figure 5 A local enlarged schematic diagram of location I;

[0041] Figure 7 This is a schematic structural diagram of the frame in the embodiment of the present utility model;

[0042] Figure 8 for Figure 7 A local enlarged schematic diagram of point J;

[0043] Figure 9 for Figure 7 A local enlarged schematic diagram of K;

[0044] Figure 10 This is a side view of a wafer status detection device in an embodiment of the present utility model;

[0045] Figure 11 for Figure 10 A local enlarged schematic diagram of L;

[0046] Figure 12 This is a schematic structural diagram of the comb teeth in the embodiment of the present utility model;

[0047] Figure 13 for Figure 12 A local enlarged schematic diagram of point M;

[0048] Figure 14 A schematic diagram of an embodiment of the present invention wherein the beam sensor is aligned with the top wafer;

[0049] Figure 15 Schematic diagram of the position of the wafer status sensor corresponding to the comb teeth when the through-beam sensor is aligned with the top wafer in an embodiment of the present invention;

[0050] Figure 16 A side view of the embodiment of the present invention showing the alignment of the beam sensor with the top wafer;

[0051] Figure 17 This is a superimposed waveform diagram of the first detection signal and the second detection signal in an embodiment of the present utility model;

[0052] Figure 18This is a schematic diagram of the lifting mechanism to the Mapping starting point in the embodiment of the present utility model;

[0053] Figure 19 This is a front view of the lifting mechanism at the Mapping starting point in the embodiment of the present utility model;

[0054] Figure 20 This is a schematic diagram of driving the through-beam sensor to extend to the wafer box in an embodiment of the present invention;

[0055] Figure 21 This is a schematic diagram of the lifting mechanism descending to the Mapping end position in the embodiment of the utility model;

[0056] Figure 22 This is a front view of the lifting mechanism in the embodiment of the utility model descending to the mapping end position;

[0057] Figure 23 This is a schematic diagram of driving the through-beam sensor to return to the standby position in an embodiment of the present utility model;

[0058] Figure 24 This is a schematic diagram of the lifting mechanism in the embodiment of the utility model descending to the lower position;

[0059] Figure 25 This is a front view of the lifting mechanism in the embodiment of the utility model descending to the lower position.

[0060] In the accompanying drawings: 1. lifting mechanism; 101. lifting body; 102. comb teeth; 103. comb teeth; 104. light-transmitting tooth groove; 105. first light-transmitting tooth groove; 106. second light-transmitting tooth groove; 107. third light-transmitting tooth groove; 108. single-axis robot; 109. single-axis robot fixed block; 110. single-axis robot fixed block support plate; 111. servo motor; 112. first slider; 113. first guide rail slider; 114. first swing cylinder; 115. first swing cylinder fixed block; 116. first rocker; 117. first bearing; 118. lifting position sensor; 119. induction sheet; 120. sensor fixing plate; 121. sensor fixing block; 122. second slider; 123. second guide rail slider; 124. first Two swing cylinders; 125, second swing cylinder fixing block; 126, second rocker; 127, second bearing; 128, first position sensor; 129, second position sensor; 130, optical fiber amplifier; 131, drag chain; 2, wafer status detection mechanism; 201, frame; 202, through-beam sensor; 203, wafer status sensor; 204, through-beam sensor fixing block; 3, fixed frame; 301, carrier platform; 4, opening door panel; 401, connecting rod; 5, pneumatic mechanism; upper limit sensor 601, upper position sensor 602, starting position sensor 603, origin position sensor 604, end position sensor 605, lower position sensor 606, upper limit sensor 607; top wafer 7; wafer box 8. DETAILED DESCRIPTION

[0061] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0062] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features therein can be combined with each other.

[0063] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but they are not intended to limit the present invention.

[0064] A wafer status detection device, such as Figures 1 to 25 Shown, including,

[0065] The lifting mechanism 1 includes a lifting body 101 that can move up and down along the direction of wafer stacking, and a comb tooth bar 102 fixed along the lifting direction is provided on one side of the lifting mechanism 1;

[0066] The wafer state detection mechanism 2 is connected to the lifting body 101 and includes:

[0067] The through-beam sensor 202 is mounted on a horizontally movable frame 201 and is controllably positioned on both sides of the wafer. The through-beam sensor 202 is driven to move up and down by the lifting body 101. The through-beam sensor 202 outputs a first detection signal indicating that the wafer is blocking light during the lifting process.

[0068] The wafer status sensor 203 is disposed on the lifting body 101 . The lifting body 101 drives the wafer status sensor 203 to move up and down. The wafer status sensor 203 outputs a second detection signal that is shielded by the comb teeth 102 during the lifting process.

[0069] Specifically, the wafer status detection device provided by the present invention is suitable for use in a front-end module 10 of a closed device, such as the B300 EFEM, and can detect the status of wafers within a front-opening wafer cassette 8. Recognizing that the prior art does not completely eliminate the impact of slight jitter in the status detection unit (mapping unit) on sensor detection results, the present invention employs a double-check mechanism by superimposing two sets of detection signals for discrimination. This mechanism offsets detection errors caused by minor vibrations or movement that may exist in the first detection method, thereby significantly improving the accuracy and reliability of wafer status detection.

[0070] The basic idea of ​​wafer status detection of the present invention is as follows: when the wafer status detection mechanism 2 moves up and down, the through-beam sensor 202 outputs a first detection signal of the wafer being shielded during the lifting process. The signal of the through-beam sensor 202 arranged above the wafer status detection mechanism 2 is used to calculate the time during which the wafer is shielded, and the displacement of each wafer in the wafer box 8 during the shielding time is calculated by the speed of the servo motor 111 and the lead of the screw of the single-axis robot 108. The specific state of the wafer in the wafer box 8 is judged from the calculated displacement value, such as no wafer, normal wafer, thick wafer, thin wafer, stacked wafer and crossed wafer, etc.; and, while the wafer status detection mechanism 2 moves up and down, the wafer status sensor 203 outputs a second detection signal of the wafer being shielded by the comb teeth 102 during the lifting process. The first detection signal and the second detection signal are compared, and the signals are superimposed and judged to determine whether the wafer is an empty wafer, a normal wafer, a crossed wafer or a warped wafer. The present invention can compensate for the influence of slight shaking of the wafer status detection mechanism 2 on the sensor detection result, so that the detection result is more accurate.

[0071] In a preferred embodiment, the comb bar 102 has comb teeth 103 that match the number of wafers, the spacing between the comb teeth 103 corresponds to the spacing between the wafers, and each comb tooth 103 includes a plurality of light-transmitting tooth grooves 104 .

[0072] Specifically, the present invention provides a comb bar 102 on the lifting mechanism 1. Generally, the wafer cassette 8 is provided with 25 wafer slots, but there are also cases with 26 wafer slots. To ensure compatibility, the comb bar 102 of this embodiment is provided with 26 comb teeth 103. The spacing between each comb tooth 103 is 10 mm, which is consistent with the 10 mm spacing between two adjacent wafer slots in the wafer cassette 8.

[0073] More specifically, Figure 12 , Figure 13 As shown, each set of comb teeth 103 of the present invention is provided with three light-transmitting tooth grooves 104, which are, from top to bottom, the first light-transmitting tooth groove 105, the second light-transmitting tooth groove 106 and the third light-transmitting tooth groove 107. According to the standard thickness of a 12-inch wafer of 800 μm, the spacing between each light-transmitting tooth groove 104 can be set to 1 mm. With the upper edge of the second light-transmitting tooth groove 106 located at the top of the comb tooth 103 as the reference, at this time, as shown in FIG. Figures 14 to 16 As shown, the through-beam sensor 202 is located exactly at the upper edge of the uppermost wafer 7 in the wafer box 8 (achieved by adjusting the upper and lower positions of the comb teeth 102 during debugging).

[0074] The through-beam sensor 202 descends with the lifting body 101 and passes the uppermost wafer 7. At this time, the through-beam sensor 202 is in a light-shielding state and generates a square wave signal. In the process of the through-beam sensor 202 continuously descending and being shielded by the wafer, the accumulated square wave signal constitutes a first detection signal. The wafer state sensor 203 is in an ON state when it is in the light-transmitting tooth groove 104 section and generates a second detection signal which is also a square wave signal. The first detection signal and the second detection signal are superimposed and compared for analysis, as shown in FIG. Figure 17 shown.

[0075] When the shading time of the through-beam sensor 202 is at the second light-transmitting comb tooth 103 of the corresponding comb tooth 103, it is judged as a normal film. When the through-beam sensor 202 has no shading signal in the three light-transmitting comb tooth 103 intervals of the corresponding comb tooth 103, it is judged as a blank film. When the shading time of the through-beam sensor 202 is at the third light-transmitting comb tooth 103 interval of the corresponding comb tooth 103 and the first light-transmitting comb tooth 103 interval of the next comb tooth 103, it is judged as a cross film.

[0076] When the warping degree of the wafer is large, this method can also be used to detect the warping direction of the wafer: when the shading time of the through-beam sensor 202 is between the first light-transmitting comb tooth 103 and the second light-transmitting comb tooth 103 of the corresponding comb tooth 103, it is judged as upward warping; when the shading time of the through-beam sensor 202 is between the second light-transmitting comb tooth 103 and the third light-transmitting comb tooth 103 of the corresponding comb tooth 103, it is judged as downward warping.

[0077] According to this detection method, the beam sensor 202 descends at a constant speed, detecting the wafer status of the 25 wafer slots in the wafer box 8 from top to bottom. When it descends to the mapping end position, all wafer status detection work is completed.

[0078] In a preferred embodiment, the lifting mechanism 1 further includes:

[0079] The single-axis robot 108 is mounted on the single-axis robot fixing block 109. The single-axis robot 108 is provided with a liftable screw nut, and the lift body 101 is connected to the screw nut.

[0080] The servo motor 111 has an output end connected to a lead screw in the single-axis robot 108 that matches a lead screw nut. The servo motor 111 drives the lead screw to rotate, thereby driving the lead screw nut to rise and fall.

[0081] Specifically, the servo motor 111 drives the screw inside the single-axis robot 108 to rotate, and the rotation of the screw drives the screw nut inside the single-axis robot 108 to rise and fall. The lifting body 101 is fixed on the screw nut and rises and falls with the screw nut. In the present utility model, the lifting body 101 is a plate-shaped structure.

[0082] Specifically, the single-axis robot 108 is fixed on the fixed frame 3 as a precision transmission mechanism. Specifically, the single-axis robot 108 is fixed on the single-axis robot fixed block 109, and the single-axis robot fixed block 109 is fixed on the fixed frame 3 through the single-axis robot fixed block support plate 110, ensuring its stable installation in the vertical direction.

[0083] In a preferred embodiment, the lifting mechanism 1 further includes:

[0084] The first slider 112 is horizontally movable on the lifting body 101 via the first guide slider 113, and the frame 201 is connected to the first slider 112;

[0085] The first swing cylinder 114 is fixed to the lifting body 101 through the first swing cylinder fixing block 115;

[0086] A first rocker arm 116 is connected to the output end of the first swing cylinder 114;

[0087] The first bearing 117 is disposed in the guide groove of the first slider 112 , and the first swing cylinder 114 is connected to the first bearing 117 via the first rocker 116 ;

[0088] The first position sensor 128 for detecting the position of the first slider 112 is disposed on the lifting body 101 .

[0089] Specifically, the first swing cylinder 114 is fixed to the lifting body 101 through the first swing cylinder fixing block 115. When the output end of the first swing cylinder 114 rotates, it drives the first rocker arm 116 to rotate. The rotation of the first rocker arm 116 drives the first slider 112 to move forward and backward. The first position sensor 128 is used to detect whether the corresponding sensor 202 moves forward or backward.

[0090] Specifically, the first guide rail slider 113 is horizontally mounted on the lifting body 101, and the first slider 112 is mounted on the first guide rail slider 113, enabling horizontal movement of the first slider 112 relative to the lifting body 101. The first slider 112 is connected to the frame 201, and the through-beam sensor 202 is mounted on the frame 201. Thus, the first slider 112 drives the through-beam sensor 202 through the frame 201 to move horizontally toward or away from the wafer.

[0091] To be more specific, the through-beam sensor 202 adopts a through-beam fiber optic sensor. The receiving end and the transmitting end of the through-beam sensor 202 are located on both sides of the wafer. It is connected to the top of the frame 201 through the through-beam sensor fixing block 204. The frame 201 is driven to move by the horizontal movement of the first slider 112, and the through-beam sensor 202 is extended into the wafer box 8 to scan and detect the status of the wafer in the wafer box 8 from top to bottom, and output a first detection signal.

[0092] The motion relationship of the present invention is that the first swing cylinder 124 on the lifting mechanism 1 rotates to drive the first rocker 116 to rotate, and the rotation of the first rocker 116 drives the first slider 112 and the frame 201 fixed thereon to move forward and backward; the servo motor 111 on the lifting mechanism 1 controls the single-axis robot 108 to drive the lifting body 101, the first slider 112 installed on the lifting body 101, and the frame 201 fixed thereon to perform lifting movements together, thereby driving the forward and backward and up and down movements of the corresponding radiation sensor.

[0093] To be more specific, when the lifting plate moves up and down under the action of the screw nut driven by the servo motor 111, the first slider 112 also moves in the vertical direction, and then drives the through-beam sensor 202 to move up and down in the vertical direction through the frame 201. The through-beam sensor 202 outputs a first detection signal that is blocked by the wafer during lifting.

[0094] In a preferred embodiment, it also includes:

[0095] A plurality of lifting position sensors 118 are provided on one side of the lifting mechanism 1 along the lifting direction through a sensor fixing plate 120;

[0096] The sensor sheet 119 is mounted on the lifting body 101 via a sensor fixing block 121 .

[0097] Specifically, the number of lifting position sensors 118 can be determined according to actual needs, such as Figure 6 As shown, in this embodiment, there are 7 lifting position sensors 118 as an example. They are installed on the sensor fixing plate 120 in sequence along the lifting direction, corresponding to the sensor sheet 119, and are used to detect the various preset positions of the lifting body 101 during the lifting and moving process, including the upper limit position at the top and the lower limit position at the bottom, and the rest from top to bottom are the upper position, Mapping starting point, origin, Mapping end point, and lower position; the corresponding lifting position sensors 118 include, from top to bottom, the upper limit position sensor 601, the upper position sensor 602, the starting position sensor 603, the origin position sensor 604, the end position sensor 605, the lower position sensor 606, and the upper limit position sensor 607.

[0098] In a preferred embodiment, it also includes a fixed frame 3, on which is provided a carrier platform 301 for placing the wafer box 8. The fixed frame 3 is located above the carrier platform 301 and is provided with a window. The opening of the wafer box 8 is set corresponding to the window, and the wafer layer is placed in the wafer slot of the wafer box 8; the lifting mechanism 1 is connected to the fixed frame 3 and is located below the carrier platform 301.

[0099] In a preferred embodiment, a cover opening door 4 for opening or closing the wafer box 8 is further included, which is arranged on the side of the fixed frame 3 facing away from the wafer box 8 and can be controllably moved closer to or away from the window in the horizontal direction.

[0100] In a preferred embodiment, the lifting mechanism 1 further includes:

[0101] The second slider 122 is horizontally movable on the lifting body 101 through the second guide rail slider 123. The lower end of the door panel 4 is provided with a connecting rod 401, which is connected to the second slider 122;

[0102] The second swing cylinder 124 is fixed to the lifting body 101 through the second swing cylinder fixing block 125;

[0103] The second rocker 126 is connected to the output end of the second swing cylinder 124;

[0104] The second bearing 127 is disposed in the guide groove of the second slider 122 , and the second swing cylinder 124 is connected to the second bearing 127 via the second rocker 126 ;

[0105] The second position sensor 129 for detecting the position of the second slider 122 is disposed on the lifting body 101 .

[0106] Specifically, the second swing cylinder 124 is fixed on the lifting body 101 through the second swing cylinder fixing block 125. When the output end of the second swing cylinder 124 rotates, it drives the second rocker arm 126 to rotate. The rotation of the second rocker arm 126 drives the second slider 122 to move forward and backward. The second position sensor 129 is used to detect whether the door panel 4 is moved forward or backward.

[0107] The second swing cylinder 124 is connected to the second bearing 127 in the guide groove of the second slider 122 via the second rocker 126. When the second swing cylinder 124 is in operation, the rotational motion output by it rotates the second rocker 126, which in turn drives the second slider 122 to move back and forth horizontally, thereby moving the opening door panel 4 away from or closer to the fixed frame 3.

[0108] At the same time, when the lifting body 101 is lifted and lowered by the screw nut driven by the servo motor 111, the second slider 122 also moves vertically, and then drives the opening door panel 4 to move vertically through the connecting rod 401.

[0109] In a preferred embodiment, it further includes a pneumatic mechanism 5, which is arranged at the bottom of the fixed frame 3, and the output ends of the pneumatic mechanism 5 are respectively connected to the lifting mechanism 1 and the wafer status detection mechanism 2.

[0110] Specifically, the pneumatic mechanism 5 is used to provide pneumatic output for the first swing cylinder 114 and the second swing cylinder 124. The lifting mechanism 1 is also provided with a drag chain 131 to provide safe and reliable traction and protection for the built-in cables, air pipes and other soft pipelines involved in the up and down movement of the lifting mechanism 1.

[0111] In a preferred embodiment, an optical fiber amplifier 130 is further included, which is connected to the through-beam sensor 202 to receive the first detection signal. Specifically, the optical fiber amplifier 130 is used to receive the weak first detection signal output by the through-beam sensor and enhance it through the process of photoelectric conversion and signal amplification. Through the amplified signal, any detailed changes in the wafer during the transmission process can be more sensitively captured.

[0112] The wafer box 8 opening and wafer status detection device of the present invention is mainly used on the EFEM (equipment front end module). The wafer status detection process is as follows:

[0113] Step 1: During the opening process, the servo motor 111 on the lifting mechanism 1 controls the single-axis robot 108 to drive the lifting body 101, the first slider 112 installed on the lifting body 101, and the beam sensor 202 connected to the first slider 112 through the frame 201 to descend to the mapping starting position. Figure 18 , Figure 19 As shown;

[0114] Step 2: The first swing cylinder 114 on the lifting mechanism 1 drives the first rocker 116 with the first slider 112 to extend the through-beam sensor 202 into the wafer box 8. At this time, the through-beam sensor 202 is located above the top wafer in the wafer box 8. Figure 20 As shown,

[0115] Step 3: The beam sensor 202 continues to descend at a constant speed. The beam sensor 202 detects the status of the wafers in the wafer box 8 from top to bottom. Figure 21 , Figure 22 As shown in the figure, the main innovation of this detection method is that the wafer status detection adopts a double detection mechanism (Double Check):

[0116] The first detection mechanism involves servo motor 111 controlling single-axis robot 108 to drive wafer status detection mechanism 2 up and down. The through-beam sensor 202 on wafer status detection mechanism 2 detects the wafer status of each wafer slot within wafer cassette 8 from top to bottom. The detected wafer thickness is calculated based on whether through-beam sensor 202 is shielded from light and the on and off times of the shielding signal, as well as the rotation speed of servo motor 111 and the lead of the single-axis robot 108. This thickness is then compared with program-preset thickness ranges for various wafer states to determine the wafer status of each wafer slot within wafer cassette 8: empty, normal, stacked, or crossed. However, this detection method can cause slight vibrations during operation, which can affect the sensor's detection results. To eliminate this adverse effect, the present invention employs a second detection mechanism.

[0117] The second detection mechanism is realized by the wafer status sensor 203, comb tooth bar 102 and beam sensor 202 on the lifting mechanism 1. The specific method is as follows: a comb tooth bar 102 is set on the lifting mechanism 1. Generally, the wafer box 8 is provided with 25 wafer slots, but there are also cases with 26 wafer slots. In order to ensure compatibility, the comb tooth bar 102 of this embodiment is provided with 26 comb teeth 103. The spacing between each comb tooth 103 is 10 mm, which is consistent with the spacing of 10 mm between two adjacent wafer slots in the wafer box 8; each set of comb teeth 103 is set There are three light-transmitting tooth grooves 104, which are the first light-transmitting tooth groove 105, the second light-transmitting tooth groove 106 and the third light-transmitting tooth groove 107 from top to bottom. According to the standard thickness of 12-inch wafers is 800μm, the spacing between each light-transmitting tooth groove 104 can be set to 1mm. The upper edge of the second light-transmitting tooth groove 106 located at the top of the comb tooth 103 is used as the reference. At this time, the beam sensor 202 is exactly at the upper edge of the top wafer 7 in the wafer box 8 (achieved by adjusting the upper and lower positions of the comb tooth bar 102 during debugging). The through-beam sensor 202 descends with the lifting body 101 and passes over the top wafer 7. At this time, the through-beam sensor 202 is in a light-shielded state and generates a square wave signal. As the through-beam sensor 202 continues to descend and is shielded by the wafer, the accumulated square wave signal constitutes a first detection signal. The wafer status sensor 203 is in an ON state when it is in the light-transmitting tooth groove 104 interval, generating a second detection signal that is also a square wave signal. The first detection signal and the second detection signal are superimposed and compared for analysis. When the light-shielding time of the through-beam sensor 202 is within the second light-transmitting comb tooth 103 of the corresponding comb tooth 103, it is determined to be a normal film. When the through-beam sensor 202 does not have a light-shielding signal in all three light-transmitting comb tooth 103 intervals of the corresponding comb tooth 103, it is determined to be a blank film. When the light-shielding time of the through-beam sensor 202 is within the third light-transmitting comb tooth 103 interval of the corresponding comb tooth 103 and the first light-transmitting comb tooth 103 interval of the next comb tooth 103, it is determined to be a cross film. This method can also be used to detect the direction of wafer warpage when the wafer has a significant degree of warpage: upward warpage is detected when the through-beam sensor 202's shielding time falls between the first and second transmissive comb teeth 103 of the corresponding comb teeth 103; downward warpage is detected when the through-beam sensor 202's shielding time falls between the second and third transmissive comb teeth 103 of the corresponding comb teeth 103. Using this detection method, the through-beam sensor 202 descends at a constant speed, sequentially detecting the wafer status of each of the 25 wafer slots in the wafer cassette 8 from top to bottom. Upon reaching the mapping endpoint, all wafer status detection is complete.

[0118] Step 4: The first swing cylinder 114 on the lifting mechanism 1 drives the first rocker 116 with the first slider 112 to move the beam sensor 202 fixed on the frame 201 back to the designated standby position. Figure 23 As shown;

[0119] Step 5: The lifting mechanism 1 drives the wafer status detection mechanism 2 to descend to the set position, that is, to the lower position. At this point, the wafer box 8 is opened and the wafer status detection is completed. Figure 24 , Figure 25 As shown;

[0120] Step 6: When the cover needs to be closed, the cover of the wafer box 8 and the wafer status detection are completed according to the reverse steps above.

[0121] Through the above steps, when the wafer state detection mechanism 2 moves up and down, the through-beam sensor 202 outputs a first detection signal of the wafer being shielded during the lifting process. The signal of the through-beam sensor 202 arranged above the wafer state detection mechanism 2 is used to calculate the shielding time of the wafer, and the displacement of each wafer in the wafer box 8 during the shielding time is calculated through the speed of the servo motor 111 and the lead of the screw of the single-axis robot 108. The specific state of the wafer in the wafer box 8 is judged from the calculated displacement value, such as no wafer, normal wafer, thick wafer, thin wafer, stacked wafer and cross wafer, etc.; and, while the wafer state detection mechanism 2 moves up and down, the wafer state sensor 203 outputs a second detection signal of the wafer being shielded by the comb tooth bar 102 during the lifting process. The first detection signal and the second detection signal are compared, and the signals are superimposed and judged to judge whether the wafer is an empty wafer, a normal wafer, a cross wafer or a warped wafer. This can compensate for the influence of slight shaking of the wafer state detection mechanism 2 on the sensor detection result, making the detection result more accurate.

[0122] The above description is only a preferred embodiment of the present invention and does not limit the implementation method and protection scope of the present invention. For those skilled in the art, it should be aware that all solutions obtained by equivalent substitutions and obvious changes made using the description and illustrations of the present invention should be included in the protection scope of the present invention.

Claims

1. A wafer status detection device, characterized in that: include, A lifting mechanism (1), the lifting mechanism (1) comprising a lifting body (101) capable of lifting and lowering along a direction in which wafers are stacked, and a comb tooth bar (102) fixed along the lifting direction is provided on one side of the lifting mechanism (1); A wafer state detection mechanism (2) is connected to the lifting body (101), and the wafer state detection mechanism (2) includes: A beam sensor (202) is provided on a frame (201) movable in a horizontal direction and controllably located on both sides of the wafer. The beam sensor (202) is driven to move upward and downward by the lifting body (101), and the beam sensor (202) outputs a first detection signal when being shielded by the wafer during the lifting process. The wafer status sensor (203) is arranged on the lifting body (101), and the wafer status sensor (203) is driven to move up and down by the lifting body (101). The wafer status sensor (203) outputs a second detection signal that is shielded by the comb teeth (102) during the lifting process.

2. The wafer status detection device according to claim 1, wherein: The comb tooth bar (102) is provided with comb teeth (103) adapted to the number of the wafers, the spacing between the comb teeth (103) corresponds to the spacing between the wafers, and each comb tooth (103) includes a plurality of light-transmitting tooth grooves (104).

3. The wafer status detection device according to claim 1, wherein: The lifting mechanism (1) further comprises: A single-axis robot (108) is arranged on a single-axis robot fixing block (109); a liftable screw nut is provided in the single-axis robot (108); and the lifting body (101) is connected to the screw nut; A servo motor (111) has an output end connected to a screw rod in the single-axis robot (108) that cooperates with the screw rod nut. The servo motor (111) drives the screw rod to rotate, thereby driving the screw rod nut to rise and fall.

4. The wafer status detection device according to claim 1, wherein: The lifting mechanism (1) further comprises: A first slider (112) is disposed on the lifting body (101) so as to be horizontally movable via a first guide rail slider (113), and the frame (201) is connected to the first slider (112); A first oscillating cylinder (114) is fixed on the lifting body (101) via a first oscillating cylinder fixing block (115); A first rocker (116) connected to an output end of the first swing cylinder (114); A first bearing (117) is disposed in a guide groove of the first slider (112); the first swing cylinder (114) is connected to the first bearing (117) via the first rocker (116); A first position sensor (128) for detecting the position of the first slider (112) is provided on the lifting body (101).

5. The wafer status detection device according to claim 1, wherein: Also includes, A plurality of lifting position sensors (118) are arranged on one side of the lifting mechanism (1) along the lifting direction through a sensor fixing plate (120); The sensing sheet (119) is arranged on the lifting body (101) through a sensor fixing block (121).

6. The wafer status detection device according to claim 1, wherein: The invention also includes a fixed frame (3), wherein a carrier platform (301) for placing a wafer box (8) is provided on the fixed frame (3), and a window is provided on the fixed frame (3) above the carrier platform (301), and the opening of the wafer box (8) is arranged corresponding to the window, and the wafer layer is placed in the wafer slot of the wafer box (8); the lifting mechanism (1) is connected to the fixed frame (3) and is located below the carrier platform (301).

7. The wafer status detection device according to claim 6, wherein: It also includes a cover opening door (4) for opening or closing the wafer box (8), which is arranged on the side of the fixed frame (3) facing away from the wafer box (8) and can be controlled to move closer to or farther away from the window in the horizontal direction.

8. The wafer status detection device according to claim 7, wherein: The lifting mechanism (1) further comprises: A second slider (122) is disposed on the lifting body (101) so as to be horizontally movable via a second guide rail slider (123); a connecting rod (401) is provided at the lower end of the opening door panel (4); and the connecting rod (401) is connected to the second slider (122); A second oscillating cylinder (124) is fixed on the lifting body (101) via a second oscillating cylinder fixing block (125); A second rocker (126) connected to the output end of the second swing cylinder (124); A second bearing (127) is disposed in a guide groove of the second slider (122); the second swing cylinder (124) is connected to the second bearing (127) via the second rocker (126); A second position sensor (129) for detecting the position of the second slider (122) is provided on the lifting body (101).

9. The wafer status detection device according to claim 6, wherein: It also includes a pneumatic mechanism (5) which is arranged at the bottom of the fixed frame (3), and the output end of the pneumatic mechanism (5) is connected to the lifting mechanism (1).

10. The wafer status detection device according to claim 1, wherein: It also includes an optical fiber amplifier (130) connected to the corresponding radiation sensor (202) and receiving the first detection signal.

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