Intelligent wafer box with state monitoring function and monitoring method thereof

Abstract

The application discloses an intelligent wafer box with a state monitoring function, comprising a wafer box body, characterized in that: an illumination module and a camera module are fixedly installed on the outer top of the wafer box body, a vertical through hole is arranged on the top of the wafer box body, a light-transmitting isolation window for light transmission is fixedly installed at the bottom of the vertical through hole corresponding to a light source, a transparent isolation window for clear imaging is fixedly installed at the bottom of the vertical through hole corresponding to a lens, the illumination module and the camera module are driven and controlled by a power module and a driving control module, four quadrant areas are formed on the plane in the top-down direction of the inner top of the wafer box body, and one independently driven and controlled illumination module is arranged in each quadrant area; and the camera module is located at the midpoint position of the four quadrant areas. The application further discloses a monitoring method. The application has the advantages that high cleanliness can be better maintained, and the yield of wafer processing can be improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of wafer boxes applied to the Internet of Things, and particularly relates to an intelligent wafer box with a state monitoring function. BACKGROUND

[0002] A wafer box is an important tool for storing, transferring and protecting wafers in a semiconductor chip manufacturing process and is widely used in the entire process of semiconductor chip production (according to statistics, a wafer box needs to contact 100-200 process tools in semiconductor chip manufacturing). Based on the specific requirements of the semiconductor chip production environment, the wafer box must meet and have the requirements of impact resistance, anti-static and extremely high cleanliness.

[0003] The chip manufacturing process is complex and very demanding. As the semiconductor chip process has been reduced to 7nm (and below), the size of the particles that endanger the wafer yield has also gradually decreased, which makes the requirements for the semiconductor chip production environment, especially the wafer box, higher and higher (in terms of chemical stability, heat resistance, low particle generation and intelligence).

[0004] The patent document with the publication number CN120015660A discloses a "wafer placement state detection method in a wafer box and a wafer state detection system" in the prior art. The technical solution includes a box body, one end of the box body in a first direction is open, the box body is spaced apart along a second direction and has a plurality of slots, the plurality of slots have a plug opening towards the opening end of the box body for installing a plurality of wafers; a wafer state detection system is arranged on the wafer box, the wafer state detection system includes at least one signal transceiver and a controller in electrical connection with the signal transceiver, and the wafer placement state detection method in the wafer box includes: after the wafer is inserted into the slot and the signal transceiver is located at the set detection position, the signal transceiver sends a detection signal; the return signal received by the signal transceiver is acquired, and whether the placement state of the wafer is correct is determined according to the return signal.

[0005] The above "wafer placement state detection method in a wafer box and a wafer state detection system" still has the following disadvantages: each signal transceiver in the wafer state detection system is fixedly installed in the interior of the wafer box or the outer side of the front open door of the wafer box, and the placement state of the wafer is detected in the horizontal and vertical directions. However, the device fixedly installed in the interior of the wafer box will adversely affect the anti-static property and the extremely high cleanliness of the interior of the wafer box.

[0006] Therefore, the applicant considers designing an intelligent wafer box with a state monitoring function and a monitoring method that can better maintain high cleanliness. SUMMARY

[0007] In view of the above deficiencies of the prior art, the technical problem to be solved by the present application is:

[0008] How to provide a smart wafer box with state monitoring function and better maintain high cleanliness and its monitoring method.

[0009] In order to solve the above technical problems, the application adopts the following technical solutions:

[0010] A smart wafer box with state monitoring function, the smart wafer box is a front opening unified pod and includes a wafer box body, characterized in that:

[0011] The outer top of the wafer box body is fixedly installed with an illumination module and a camera module, and the top of the wafer box body is provided with vertical through holes for the light source of the illumination module and the lens of the camera module to independently penetrate and one-to-one correspond:

[0012] The bottom of the vertical through hole corresponding to the light source is fixedly installed with a light-transmitting isolation window for the light source to transmit through; the bottom of the vertical through hole corresponding to the lens is fixedly installed with a transparent isolation window for clear imaging; the light-transmitting isolation window and the transparent isolation window can be used to isolate the inner and outer spaces of the wafer box body;

[0013] The illumination module and the camera module are driven and controlled by a power module and a driving control module; the inner top of the wafer box body forms four quadrant regions in the plane of the top view direction, and each quadrant region is provided with one independently driven and controlled illumination module; the camera module is located at the midpoint position of the four quadrant regions.

[0014] Compared with the prior art, the smart wafer box with state monitoring function provided by the application has the following beneficial effects:

[0015] 1. Ensure clear imaging and uniform illumination

[0016] By providing an illumination module and a camera module on the top of the wafer box, the vertical through holes penetrated by the light source of the illumination module and the lens of the camera module are isolated from each other and form two independent light channels, so that the illumination light can transmit through the light-transmitting isolation window, avoid the interference of light source transmission or refraction on camera imaging, and the camera can obtain clear shooting images, thereby better realizing reliable shooting and monitoring of the state of wafer in place, offset, warping, double pieces, notches and defects.

[0017] 2. Maintain a high clean environment

[0018] The light-transmitting isolation window and the transparent isolation window both play a role in isolating the inner and outer environments of the wafer box, preventing external dust, moisture or acid-base gas from entering the wafer box, and preventing particles or heat generated by the illumination and camera modules from entering the wafer box cavity, thereby effectively maintaining the high cleanliness required during wafer storage and transfer.

[0019] 3. Improve the multifunctionality, reliability and detection accuracy of wafer state monitoring

[0020] By dividing the internal area of the wafer box body into four quadrants in the top view direction, and arranging the camera module at the intersection center position of the four quadrant regions, the illumination light can be uniformly illuminated from multiple directions to the wafer surface, and the imaging field of view is located on the central axis of the symmetric illumination.

[0021] Thus, high uniformity illumination and low shadow imaging of the wafer surface can be achieved, significantly improving the clarity and accuracy of image recognition; at the same time, each quadrant illumination module can be independently controlled, and through zoned lighting or brightness difference analysis, the offset direction, wafer position and local height difference of the wafer can be further judged, thereby realizing precise detection of multiple states. The structure has simple optical path, uniform illumination, easy calibration and maintenance, and improves the reliability and detection accuracy of wafer state monitoring.

[0022] 4. Flexible and reliable power supply

[0023] Any one of the two modes of power supply structure (box-mounted and carrier table side) can be used in combination with the on-site situation:

[0024] The first (preferred) scheme is that the power module and the drive control module can be fixedly installed on the wafer box body, so that the wafer box can independently complete the monitoring during the handling and temporary storage process; and the deployment cost of the scheme can be reduced (avoiding the uniform installation of power modules and drive control modules on each carrier table).

[0025] The second (secondary) scheme is to provide a plug on the bottom of the wafer box body, which is electrically connected with the illumination module and the camera module and is used for docking with the socket on the carrier table (wafer box). In this way, stable and continuous power supply and control signal connection can be obtained when the wafer box is docked with the machine or parked on the carrier table, thereby ensuring the continuity and adaptability of the system in different application scenarios.

[0026] 5. Improve automation and production yield

[0027] The intelligent wafer box can collect wafer state information in real time at different links of the production line, reduce the loss caused by manual intervention and abnormal placement of wafers, and thereby improve the automation level of the semiconductor production process and better ensure the yield of wafer processing and production.

[0028] The monitoring method of the intelligent wafer box with state monitoring function is characterized by comprising the following steps:

[0029] S1, control the illumination module to emit illumination light to the internal wafer through the light-transmitting isolation window on the top of the wafer box in a preset illumination mode; in each preset illumination mode, the camera module sequentially collects images and stores them;

[0030] S2, identifying wafer state based on collected image data, the wafer state including in-place, offset, mis-slot, warped, double wafer stacking, notch direction and edge collapse state.

[0031] The above monitoring method has the advantages of:

[0032] 1. The hardware structure of the intelligent wafer box is relatively simple, and after the scheme is adopted, rich wafer state monitoring can be realized by using a simple hardware structure, and a better technical effect can be obtained.

[0033] 2. The intelligent wafer box can be used to automatically identify and replace manual inspection, which can reduce human error and subjective judgment deviation, shorten the detection period, and reduce labor input and production cost.

[0034] 3. Through real-time detection and identification, wafer loading abnormalities or damage risks can be found early, and timely warning or process stopping can be sent, thereby effectively reducing the scrap rate and improving the overall production yield.

[0035] 4. Through the automatic image acquisition and identification process, the detection result can be fed back to the machine control system in real time, realizing online monitoring and closed-loop control of the production process, and further helping to improve the production yield of chips. BRIEF DESCRIPTION OF DRAWINGS

[0036] Figure 1 is a schematic diagram of the three-dimensional structure of the intelligent wafer box (on the bearing table) of the present application with state monitoring function;

[0037] Figure 2 is a top view of the intelligent wafer box (on the bearing table) of the present application with state monitoring function;

[0038] Figure 3 is Figure 2 A-A line section view;

[0039] Figure 4 is Figure 3 a local enlarged view of the dotted circle in B-B line section view;

[0040] Figure 5 is Figure 2 B-B line section view;

[0041] Figure 6 is Figure 5 a local enlarged view of the dotted circle in B-B line section view;

[0042] Figure 7 is a schematic diagram of the distribution of the illumination module in the intelligent wafer box of the present application with state monitoring function in four quadrants (top view direction);

[0043] Figure 8 isFigure 7 A perspective view (bottom view) of the illumination module and the camera module;

[0044] Figure 9 A perspective view (bottom view) of the smart wafer box with state monitoring function of the present application;

[0045] Figure 10 A perspective structural schematic view of the bearing table;

[0046] Figure 11 A polar coordinate schematic view of the wafer (and its notch);

[0047] Figure 12 A flow chart of the monitoring method of the smart wafer box with state monitoring function of the present application;

[0048] The marks in the figure are:

[0049] 1 wafer box body, 10 light-transmitting isolation window, 11 transparent isolation window, 12 annular step, 13 convex ring, 14 vertical through hole, 141 annular protrusion, 142 annular groove, 15 O-shaped sealing ring, 16 handle, 17 RFID tag, 18 power module, 19 drive control module;

[0050] 2 illumination module;

[0051] 3 camera module;

[0052] 4 receiving coil assembly;

[0053] 5 bearing table, 51 transmitting coil assembly;

[0054] 6 wafer, 61 notch. DETAILED DESCRIPTION

[0055] The present application will be further described in detail below in combination with the drawings.

[0056] Example 1, as shown: Figures 1 to 12

[0057] A smart wafer box with state monitoring function, the smart wafer box is a front opening unified pod and comprises a wafer box body 1, an illumination module 2 and a camera module 3 are fixedly installed on the outer top of the wafer box body 1, a vertical through hole 14 is arranged on the top of the wafer box body 1 for the light-emitting source of the illumination module 2 and the lens of the camera module 3 to independently penetrate and one-to-one correspond:

[0058] ​A light-transmitting isolation window 10 for the light source to pass through is fixedly installed at the bottom of the vertical through hole 14 corresponding to the light-emitting source; a transparent isolation window 11 for clear imaging is fixedly installed at the bottom of the vertical through hole 14 corresponding to the lens; the light-transmitting isolation window 10 and the transparent isolation window 11 can be used to isolate the inner and outer spaces of the wafer box body 1.

[0059] The illumination module 2 and the camera module 3 are driven and controlled by a power module 18 and a driving control module 19.

[0060] The inner top of the wafer box body 1 is formed with four quadrant regions in the plane in the top view direction, and each quadrant region is provided with one independently driven and controlled illumination module 2; the camera module 3 is located at the midpoint position of the four quadrant regions.

[0061] By dividing the internal region of the wafer box body 1 into four quadrants in the top view direction, setting the illumination module 2 in each quadrant region, and arranging the camera module 3 at the intersection center position of the four quadrant regions, the illumination light can be uniformly irradiated to the wafer surface from multiple directions, and the imaging field of view is located on the central axis of the symmetrical illumination.

[0062] Thus, high uniformity illumination and low shadow imaging of the wafer surface can be realized, and the clarity and accuracy of image recognition are significantly improved; at the same time, the illumination modules 2 in each quadrant can be independently controlled, and through zoned lighting or brightness difference analysis, the offset direction, warped position and local height difference of the wafer can be further judged, so as to realize precise detection of multiple states. The structure has simple light path, uniform illumination, easy calibration and maintenance, and improves the reliability and detection precision of wafer state monitoring.

[0063] In implementation, the illumination module 2 in each quadrant region preferably includes a bright field surface light source and a dark field light source, both of which can be independently controlled in zones; or (as shown in Figure 2 、 7 and 8) the illumination module 2 in each quadrant region can control the brightness, i.e. it can be a bright field surface light source or a dark field light source.

[0064] The power module and the driving control module 19 are fixedly installed on the outer side of the wafer box body 1;

[0065] The power module includes at least one rechargeable power source, which is a rechargeable battery or a super capacitor;

[0066] The driving control module 19 includes:

[0067] an illumination driving unit (not shown in the figure) for providing constant current driving for the illumination module 2;

[0068] a camera control unit for powering the camera module 3 and controlling image acquisition;

[0069] a wireless communication unit for wireless communication connection with the outside.

[0070] The above preferred structure has the advantages of:

[0071] 1. The wafer box body 1 itself independently powers the monitoring-related functional modules, so that the intelligent wafer box can still independently complete lighting and image acquisition when it is being transported, temporarily stored, or not connected to the machine (the carrying table 5), thereby ensuring the continuity and flexibility of the state monitoring function.

[0072] 2. The lighting driving unit can provide constant current output for the lighting module 2, avoiding flickering or uneven brightness of the light source caused by current fluctuations, thereby ensuring stable and uniform lighting effects, which is conducive to the camera obtaining clear and reliable images.

[0073] 3. The camera control unit can provide stable power and control signals for the camera module 3, and realize the setting of sampling frame rate, exposure parameters, etc., so that the camera can stably collect wafer in-place state and defect information, thereby improving image imaging quality and detection accuracy.

[0074] 4. The wireless communication unit can realize wireless data interaction between the intelligent wafer box and the external system, simplifying and avoiding complex wiring, so that wafer state information can be transmitted and processed in real time in the production line, thereby facilitating the improvement of production line automation and remote monitoring level.

[0075] In implementation, the driving control module 19 adopts a control circuit board with a single-chip microcomputer or FPGA.

[0076] In implementation, the wireless communication unit can be selected from NB-IoT, LoRa, WiFi, or 5G wireless communication modules.

[0077] The power module further includes a wireless charging module electrically connected to the rechargeable power supply.

[0078] The wireless charging module includes a receiving coil assembly 4 fixedly arranged on the outer side of the bottom of the wafer box body 1, which is used to electromagnetically couple with a corresponding sending coil assembly 51 arranged on the carrying table 5 when the wafer box body 1 is placed on the carrying table 5, thereby realizing non-contact wireless charging of the power module.

[0079] The above wireless charging module has the advantages of:

[0080] 1. By incorporating a wireless charging module and receiving coil assembly 4 within the power module, the wafer cassette can achieve electromagnetic coupling with its corresponding transmitting coil assembly 51 when placed on the support platform 5. This enables contactless charging of batteries or supercapacitors, avoiding the mechanical wear or poor contact associated with traditional plug-and-play power supply interfaces and ensuring more reliable and long-lasting charging. Simultaneously, reducing losses caused by frequent plugging and unplugging of physical interfaces helps extend the wafer cassette's lifespan and improves overall reliability and stability.

[0081] 2. It adopts wireless charging, eliminating the need for manual cable plugging or unplugging or additional docking actions. Simply place the wafer box on the carrier platform 5 to achieve automatic charging, which can improve the convenience and automation of use.

[0082] 3. Non-contact charging avoids dust particles that may be generated during the insertion and removal of mechanical interfaces, thus better ensuring the cleanliness of the internal environment of the wafer box and meeting the stringent requirements of semiconductor manufacturing processes for a high-cleanliness environment.

[0083] In practice, the preferred non-contact charging method features a receiving coil with a frequency of 110–200 kHz, a coupling coefficient ≥0.2, a transmitting power of 5 to 20 W, and a thermal management temperature ≤60℃.

[0084] The light-transmitting isolation window 10 and the transparent isolation window 11 are both made of transparent polycarbonate material and have a coating layer on the surface facing upward toward the inside of the wafer box body 1. The coating layer is made of fluorinated ethylene propylene material.

[0085] The above coating layer is made of fluorinated ethylene propylene (FEP), which has excellent chemical corrosion resistance, high light transmittance and excellent temperature adaptability (material stability in the range of -200℃ to 200℃), so it can reliably adapt to the wafer processing environment for a long time.

[0086] Transparent polycarbonate has high mechanical strength, is easy to process and mold, and has high transparency, making it more effective as a light-transmitting isolation window 10 and a transparent isolation window 11.

[0087] When implementing this method, the thickness of the coating layer is preferably 0.2-1mm; the thickness of the transparent polycarbonate material is 1.5-4mm, with a surface haze of <1% and a light transmittance of >90%.

[0088] In practical use, the outer surfaces of the coating layers of both the light-transmitting isolation window 10 and the transparent isolation window 11 can be cleaned and wiped with alcohol or isopropyl alcohol. Alternatively, the light-transmitting isolation window 10 and the transparent isolation window 11 can be inspected or replaced periodically (e.g., quarterly).

[0089] See Figures 3-6As shown, the outer side surface of each of the light-transmitting isolation window 10 and the transparent isolation window 11 in the circumferential direction is radially outwardly convexly formed with a ring-shaped step 12 and a ring-shaped convex ring 13 with a semicircular cross section; the ring-shaped step 12 and the convex ring 13 are axially spaced apart;

[0090] The inner wall bottom of the corresponding vertical through hole 14 is radially inwardly convexly formed with a ring-shaped convexity 141;

[0091] The radially inner side surface of the ring-shaped convexity 141 is provided with a ring-shaped groove 142 for the convex ring 13 to be clamped into; and when the convex ring 13 is clamped into the ring-shaped groove 142, the ring-shaped step 12 and the ring-shaped convexity 141 axially abut against each other, and an O-shaped sealing ring 15 is interposed therebetween, the O-shaped sealing ring 15 being made of perfluoroether rubber.

[0092] The above structure has the following advantages:

[0093] 1. Stable structure assembly and reliable installation

[0094] By forming the ring-shaped step 12 and the convex ring 13 on the radially outer side surface of the light-transmitting isolation window 10 and the transparent isolation window 11, and correspondingly providing the ring-shaped convexity 141 and the ring-shaped groove 142 on the inner bottom wall of the vertical through hole 14, the isolation window can be fixedly connected with the wafer box body 1 in a clamping manner, which is convenient to install and accurate to position, and avoids loosening or falling off of the isolation window during handling or vibration.

[0095] 2. Efficient sealing and preventing pollution

[0096] The O-shaped sealing ring 15 is arranged between the ring-shaped step 12 and the ring-shaped convexity 141, and the O-shaped sealing ring 15 is preferably made of perfluoroether rubber material. The perfluoroether rubber has excellent chemical resistance and heat resistance, and does not produce outgassing or particle shedding, which ensures long-term stable and reliable sealing performance, effectively maintains high cleanliness of the wafer storage environment, and maintains a good environment in the space inside the vertical through hole 14 for device setting.

[0097] 3. Easy to disassemble, assemble and maintain

[0098] Through the clamping structure of the convex ring 13 and the ring-shaped groove 142 and the design of the O-shaped sealing ring 15, the sealing performance is maintained, and the replacement and cleaning operation of the isolation window is also facilitated, which improves the maintainability and long-term use reliability.

[0099] In implementation, the wafer box body 1 is fixedly provided with an RFID tag 17; the left and right sides of the outer side of the wafer box body 1 are each fixedly provided with a long strip-shaped handle 16 inclined at an angle of 30-60 degrees with the horizontal plane, and the two ends of the length direction of the handle 16 are connected with the outer side of the wafer box body 1 through a connecting plate block, the connecting plate block is overall inclined along the handle 16, and the plate surface of the connecting plate block constitutes a label bonding area and is bonded with the RFID tag 17.

[0100] Based on the needs of production digitization and intelligentization, the wafer box often carries some digital information (such as wafer box ID, manufacturing information, capacity, and current location of flow, loading state, number of uses, and maintenance information) during operation, and is often bound and tracked with the MES system of the factory.

[0101] After adopting the above RFID tag 17 setting structure, the RFID tag 17 is bonded on the surface of the connecting plate block in the direction of the handle 16, so that the label plane forms a suitable angle with the external read-write equipment, avoiding signal shielding or reflection interference of the wafer box body, thereby improving the radio frequency reading distance and signal stability. Integrating the RFID tag 17 on the plate surface of the handle 16 connecting plate block can realize label installation without additional slotting or protruding structure, so that the appearance of the wafer box is simple and flat, while ensuring firm and anti-falling label installation. As an independent label bonding area, the connecting plate block can be separately disassembled when the RFID tag 17 needs to be replaced or maintained, without affecting the wafer box body, and the operation is convenient and the cost is low.

[0102] Embodiment 2 (not shown in the figure):

[0103] The difference between this embodiment and embodiment 1 is that the bottom of the wafer box body 1 is provided with a plug electrically connected with the illumination module 2 and the camera module 3, and the plug is a multi-pin blind plug structure;

[0104] The bearing table 5 is provided with the power module 18 and the drive control module 19 and the socket electrically connected with them, and the socket is a multi-pin socket structure;

[0105] The plug and the socket are provided with a guide component, so that the plug and the socket are aligned and reliably electrically connected during the wafer box body 1 is placed on the bearing table 5.

[0106] The above structure has the following advantages:

[0107] 1. Automatic docking and reliable power supply are realized

[0108] By setting a multi-pin blind plug on the bottom of the wafer box and a corresponding multi-pin socket on the bearing table 5, the plug and socket can be automatically and accurately connected during the wafer box placement process, and power supply and signal connection can be completed without manual plugging and unplugging, which is simple, stable and reliable. Moreover, the power module 18 and the drive control module 19 are both arranged on the bearing table 5.

[0109] 2. Improve the stability of electrical connection and service life

[0110] The blind plug multi-pin structure can maintain stable contact during frequent loading and unloading and transportation, avoiding the problem of poor contact caused by misalignment, wear or pollution of traditional plug-in interfaces, thereby significantly improving the electrical connection reliability and service life of the system.

[0111] 3. Guiding structure ensures accurate alignment

[0112] The guiding component can guide the plug to automatically align with the socket during the wafer box falling process, effectively preventing pin bending or poor contact caused by position deviation, and improving the mechanical connection accuracy and plug-in safety.

[0113] 4. Facilitate integration of automated production line

[0114] The structure can be used with an automatic handling robot to realize automatic placement, connection and power supply of the wafer box, further improving the automation level and production efficiency of the semiconductor production line.

[0115] In implementation, a guiding component is preferably arranged between the plug and the socket, and a precise guiding structure between the wafer box body 1 and the bearing table 5 is adopted, for example, a plurality of guiding holes arranged on the bottom of the wafer box, and a plurality of guiding columns (with chamfer or in the shape of a ball tank) arranged on the bearing table 5.

[0116] In implementation, a power supply interface (constituting a power module 18) and a data communication interface are arranged on the bearing table 5, the power supply interface is electrically connected between the socket and the power supply of the bearing table 5 through a wire, and the data communication interface is connected between the socket and the control system of the bearing table 5 through a signal cable. The control system of the bearing table 5 can adopt an independent MCU or an upper computer system.

[0117] In this way, by providing a power supply interface and a data communication interface on the bearing table 5, the wafer box can obtain stable power supply and data communication channel after being placed on the bearing table 5, thereby realizing real-time data transmission and control instruction interaction of the monitoring module. The integrated design of the power supply and communication channel forms a standardized interface structure between the wafer box and the bearing table 5, facilitating unified management and scheduling in the automatic production line, and improving system compatibility and expandability. Through the special signal cable connected to the control system, high-speed and anti-interference data transmission can be realized, ensuring that the images and state information collected by the camera are stably transmitted to the control system, improving the real-time performance and accuracy of monitoring. The power supply interface and the data communication interface adopt a separate structure, which facilitates individual replacement or upgrade of the corresponding modules during maintenance or expansion, thereby enhancing the maintainability and long-term reliability of the system.

[0118] The intelligent wafer box of embodiments 1 and 2 has the following advantages:

[0119] By providing mutually isolated light-transmitting isolation window 10 (forming a light-emitting channel) and transparent isolation window 11 (forming an imaging channel) on the top of the box body, and coating the light-transmitting isolation window 10 and the transparent isolation window 11 made of polycarbonate (PC) material with fluorinated ethylene propylene (FEP), the space inside and outside the wafer box is completely separated, which not only suppresses the crosstalk of illumination scattering on imaging, but also blocks the dust and heat of the device from entering the inner cavity, thereby realizing online visual judgment of the wafer in-situ, offset, warping, double wafer, and notches 61 / edge collapse without introducing devices into the box. The cleanliness and imaging stability are significantly improved.

[0120] The illumination module 2 adopts a combination of dark field light and bright field light in four quadrant partitions, and cooperates with each illumination module 2 to realize sequential lighting in an independently controllable manner. Based on the edge shadow / high light response difference, the directionality of the wafer warping is determined without the need for additional height sensors, thereby simplifying the structure and improving the determination reliability.

[0121] As shown in Figure 12 , the monitoring method of the intelligent wafer box with the state monitoring function includes the following steps:

[0122] The monitoring method of the intelligent wafer box with the state monitoring function includes the following steps:

[0123] S1, control the illumination module 2 to emit illumination light to the internal wafer through the light-transmitting isolation window 10 on the top of the wafer box in a preset illumination mode; in each preset illumination mode, the camera module 3 sequentially collects images and stores them;

[0124] S2, identify the wafer state based on the collected image data, the wafer state including in-situ, offset, misaligned slot, wafer warping, double wafer stacking, notch 61 direction, and edge collapse state.

[0125] In the S2 step, identifying the wafer state includes the following steps:

[0126] (1) Calculate wafer center offset by circular edge fitting to determine whether the wafer is in place or misaligned;

[0127] (2) Detect the direction of the gap 61 based on the polar coordinate expansion of the image brightness distribution;

[0128] (3) Use the radial gradient bimodal feature of the bright field image and the dark field edge width to comprehensively determine whether there is double wafer stacking;

[0129] (4) Use dark field illumination with four quadrant partition points, and determine whether the wafer is warped or not fully seated by the edge brightness difference and sharpness index of each quadrant;

[0130] (5) Determine whether the wafer has edge collapse or damage by the continuity of the edge brightness in the dark field image and the density of abnormal reflection points.

[0131] The above identification means is easy to implement and use, thereby providing comprehensive state data support for subsequent processes and reducing abnormal flow into the production line.

[0132] The monitoring method of the intelligent wafer box with the state monitoring function, before use:

[0133] First, calibrate the camera, and calibrate the camera intrinsic parameters by the checkerboard to remove distortion;

[0134] Second, take a reference frame: take and collect a frame when the wafer box is empty as a reference B;

[0135] Next, set the illumination sequence and take the wafer, and collect frames: turn on the full bright field light source (MF) and take and obtain the image I_MF, turn on the dark field light source (DF) and take and obtain the image I_DF, turn on the four quadrant dark field light source (DF) in sequence (Q1-Q4) and take and obtain the images (I_Q1-I_Q4); from the above, one frame is collected at each step, and the sequence image {I_MF, I_DF, I_Q1, I_Q2, I_Q3, I_Q4} is obtained;

[0136] Subsequently, pre-process the collected images (including removing distortion, bilateral filtering, and contrast adaptive enhancement), and execute the image recognition algorithm to determine the wafer state.

[0137] The image recognition algorithm includes the following steps:

[0138] 1. Wafer 6 in place and offset detection

[0139] Detect the wafer edge profile by the Hough circle or least squares fitting algorithm, and calculate the offset d of the fitted center from the standard slot center.

[0140] If d≤0.3mm, it is determined as "in position";

[0141] If 0.3mm < d≤1.0mm, it is determined as "slight deviation";

[0142] If d>1.0mm, it is determined as "mis-slot" or "serious deviation".

[0143] 2. Positioning gap 61 direction identification

[0144] As shown in Figure 11 , the bright-field image is polar coordinate expanded, the radius-angle intensity distribution is calculated, the template matching or the intensity valley continuous section is used to position the angle θ of the gap 61. When the length of the continuous low-brightness area of the gap 61 is greater than or equal to 6°, it is determined that the gap 61 is established, and the direction angle θ of the gap 61 is outputted, θ∈[0°, 360°].

[0145] 3. Double wafer stacking detection

[0146] The intensity profile is extracted along the multi-angle radial direction of the bright-field image, the double-peak ratio p2 of the edge gradient curve is calculated, and the edge ring width w_df is extracted in the dark-field image.

[0147] When p2≥35% and w_df≥0.35mm, it is determined that there is double wafer stacking.

[0148] 4. Wafer warping or incomplete slotting detection

[0149] The dark-field light of the four quadrants is turned on in sequence, the average brightness L_k of the edge of each quadrant is calculated, and the brightness difference Δ_k=L_k−mean(L_all) is calculated.

[0150] If |Δ_k|≥15 / 255 and the sharpness index (Laplacian variance) of the corresponding quadrant deviates from the average value, it is determined that there is a wafer warping or incomplete slotting phenomenon in the direction of the quadrant. The greater the brightness difference, the more serious the warping degree.

[0151] 5. Edge collapse or micro damage detection

[0152] The brightness distribution is extracted along the wafer edge arc line area in the dark-field image, the low-brightness continuous angle length L_gap and the high-brightness isolated peak density ρ_spike are counted.

[0153] If L_gap≥3° or ρ_spike≥2 or more abnormal reflection points exist per 30°, it is determined that the edge has edge collapse or damage defects, and the angle interval is outputted.

[0154] The monitoring method of the intelligent wafer box with a state monitoring function of the present application calculates a comprehensive state value according to the confidence of each sub-determination and outputs it, and the output data includes: wafer center offset, notch 61 angle, double wafer stacking state, warping quadrant direction, edge defect angle interval and corresponding confidence value. Through this algorithm, the automatic identification and classification of the wafer can be completed without adding additional sensors in the box. By using this technical solution, the wafer can be quickly determined in the state of in-place, offset, warping, double wafer stacking and edge collapse, and the detection accuracy is high and the reliability is strong. The state monitoring requirements of wafers of different sizes (150mm, 200mm, 300mm) can be adapted by adjusting the light source partition lighting mode and the algorithm parameters.

[0155] The following is the specific algorithm of each step of identifying and determining the wafer state:

[0156] A, in-place / offset / slot error (use circle fitting+center offset to determine whether the wafer is in the correct slot, whether it is offset), the specific steps are:

[0157] 1. Use I_MF to extract the edge, and the threshold T_canny≈[50,150];

[0158] 2. Hough circle gets candidate circles (radius r∈[0.48D,0.52D], D is the nominal diameter);

[0159] 3. Take the maximum response circle and least squares fitting to refine the circle parameters (x_c, y_c, r);

[0160] 4. Get the target center (x_0, y_0) from the bearing platform 5 geometry or camera-slot calibration;

[0161] 5. Calculate the offset d=√((x_c−x_0)^2+(y_c−y_0)^2).

[0162] The determination condition is:

[0163] In-place: d≤0.3mm;

[0164] Light offset: 0.3mm<d≤1.0mm (pre-warning);

[0165] Slot error / severe offset: d>1.0mm (alarm).

[0166] B, determine the notch 61 direction (use polar coordinate expansion+template matching to get the wafer notch 61 (orientation) angle θ), the specific steps are:

[0167] 1. Take (x_c, y_c) as the center of the circle, and do polar coordinate expansion on I_MF to get the radius-angle graph I_p(r, θ);

[0168] 2. Search intensity valley along the strip region of r≈r_edge±Δr, the gap 61 corresponds to the low intensity of continuous angular segment.

[0169] 3. Also can do NCC correlation matching with the gap 61 template, take the θ of the maximum correlation place * ; output: θ * ∈[0°,360°], for alignment / flow tracking. Threshold reference: low intensity threshold is global Otsu × 0.9; the length of continuous angular segment ≥ 6° is judged as the gap 61.

[0170] C, double piece stacking (edge radial bimodal + DF confirmed, two wafer stacking leads to edge transition zone widening, radial gradient appears bimodal; the edge scattering band will be wider and brighter under dark field illumination), the specific steps are:

[0171] 1. Extract intensity profile along N equi-angle radial (N=360 / 2°) in I_MF, do first derivative, and count the bimodal proportion p2 (two extreme values appear within r_edge±1mm and the interval is 0.15-0.6mm, which is counted as bimodal);

[0172] 2. Measure the edge ring width w_df (full width at half maximum) on I_DF;

[0173] Determination condition:

[0174] If p2≥35% and w_df≥0.35mm, it is double piece, otherwise it is single piece.

[0175] D, warped piece / not completely fallen into groove (use the edge shadow / highlight intensity difference when the four quadrant dark field Q1-Q4 is sequentially lit to infer the relative height of the four quadrants. The edge away from the notch (or warped) will change the incident angle, leading to asymmetric light reception), the specific steps are:

[0176] 1. For each quadrant graph I_Qk, calculate the average brightness L_k of the edge arc segment in the quadrant;

[0177] 2. Calculate the difference Δ_k=L_k−mean(L_all) of the four quadrants;

[0178] 3. If max|Δ_k|≥T_Δ (preset T_Δ=15 / 255) and the corresponding quadrant arc segment is simultaneously raised / lowered in the definition index (Laplacian variance) of I_MF, then the warped direction is determined;

[0179] 4. Empirically map Δ_k→ relative "height difference" level H_k∈{0,1,2} (0 normal, 2 severe).

[0180] Determination condition:

[0181] H_max=0: normal;

[0182] H_max=1: slight warping / not falling into the groove (pre-warning);

[0183] H_max=2: obvious warping (warning, quadrant direction given).

[0184] E, notch 61 / edge collapse / minor damage (through arc segment continuity in dark field: under dark field, a complete circular edge shows as a continuous high-light arc; at edge collapse / damage, there is a brightness interruption or an abnormally strong reflection peak), the specific steps are:

[0185] 1. Perform a ring projection on the r_edge±Δr band of I_DF to obtain an intensity sequence S(θ);

[0186] 2. Calculate the arc segment continuity: use a sliding window (3-5°) to count the continuous angle length L_gap below the threshold and the isolated spike density ρ_spike above the threshold;

[0187] 3. Threshold: threshold = Otsu x 0.8, L_gap≥3° or ρ_spike≥2 per 30°, then the damage / edge collapse is established;

[0188] Output the defect angle interval [θ1, θ2] and the confidence.

[0189] F, whole-process state word and confidence fusion

[0190] Output the confidence c_i for each sub-determination (based on the normalized distance from the threshold), and use a weighted maximum confidence strategy to form the overall acceptance state: STATE = argmax_i(w_i*c_i), the preset weight: in place / offset 0.3, warped piece 0.25, double piece 0.25, notch 61 edge collapse 0.2.

[0191] The above is only a preferred embodiment of the present application, it should be pointed out that, for those skilled in the art without departing from the prior art, several deformation and improvement of the technical solutions should also be considered to fall within the scope of the present application.

Claims

1. A smart wafer cassette with status monitoring function, wherein the smart wafer cassette is a front-opening wafer transport cassette and includes a wafer cassette body, characterized in that: An illumination module and a camera module are fixedly mounted on the top of the wafer box body. The top of the wafer box body has vertical through holes for the light source of the illumination module and the lens of the camera module to pass through independently and correspond one-to-one. A light-transmitting isolation window for the light source to pass through is fixedly installed at the bottom of the vertical through hole corresponding to the light source; a transparent isolation window for clear imaging is fixedly installed at the bottom of the vertical through hole corresponding to the lens; both the light-transmitting isolation window and the transparent isolation window can be used to isolate the inner and outer spaces of the wafer cassette body. The lighting module and camera module are driven and controlled by the power supply module and the drive control module; the inner top of the wafer box body has four quadrant regions in the plane in the top view direction, and each quadrant region is provided with an independently driveable lighting module; the camera module is located at the midpoint of the four quadrant regions; The power module and drive control module are fixedly mounted on the outer side of the wafer cassette body. The power module includes at least one rechargeable power source, which is a rechargeable battery or a supercapacitor. The drive control module includes: A lighting driver unit used to provide constant current drive for lighting modules; A camera control unit used to power the camera module and control image acquisition; A wireless communication unit used for external wireless communication connections.

2. The smart wafer cassette according to claim 1, characterized in that: The power module also includes a wireless charging module electrically connected to the rechargeable power supply. The wireless charging module includes a receiving coil assembly fixedly disposed on the outer side of the bottom of the wafer cassette body. The receiving coil assembly is used to electromagnetically couple with the corresponding transmitting coil assembly disposed on the support platform when the wafer cassette body is placed on the support platform, so as to realize non-contact wireless charging of the power module.

3. The smart wafer cassette according to claim 1, characterized in that: Both the light-transmitting isolation window and the transparent isolation window are made of transparent polycarbonate material, and the surface facing upward toward the inside of the wafer box body is covered with a coating layer, which is made of fluorinated ethylene propylene material.

4. The smart wafer cassette according to claim 1, characterized in that: The outer surfaces of both the light-transmitting and transparent isolation windows are radially convex with an annular step and a semi-circular convex ring; the annular step and the convex ring are spaced apart axially. The bottom of the inner wall of the corresponding vertical through hole has a ring-shaped protrusion that convexes inward along the radial direction; The annular protrusion has an annular groove on its radial inner side for the protruding ring to be engaged; and when the protruding ring is engaged in the annular groove, the annular step and the annular protrusion abut against each other in the axial direction, and an O-ring is provided between them, the O-ring being made of perfluoroether rubber.

5. The smart wafer cassette according to claim 1, characterized in that: The bottom of the wafer box body is provided with a plug that is electrically connected to the lighting module and the camera module, and the plug is a multi-pin blind-plug structure. The power module and drive control module are provided on the support platform and are electrically connected to a socket, which is a multi-pin socket structure. A guide component is provided between the plug and the socket to ensure that the plug and socket are aligned and reliably electrically connected during the placement of the wafer cassette onto the support platform.

6. The monitoring method for a smart wafer cassette with condition monitoring function as described in any one of claims 1 to 5, characterized in that, Includes the following steps: S1. The control lighting module emits illumination light to the internal wafer through the light-transmitting isolation window on the top of the wafer box in the preset lighting mode; Under each preset lighting mode, images are captured and stored sequentially by the camera module; S2. Identify wafer status based on acquired image data. Wafer status includes in-place, offset, misaligned slots, warped wafers, double wafer stacking, notch orientation, and chipped edge status.

7. The monitoring method according to claim 6, characterized in that: In step S2, identifying the wafer state includes the following steps: (1) The wafer center offset is calculated by fitting the circular edge to determine whether the wafer is in place or misaligned; (2) Detecting the notch direction based on brightness distribution unfolded from image polar coordinates; (3) Use the radial gradient bimodal feature of the bright field image and the edge width of the dark field to determine whether there is double-layer stacking; (4) Dark field illumination with four quadrants is used to determine whether the wafer is warped or not completely placed in the slot by the brightness difference and sharpness index of each quadrant edge. (5) Determine whether the wafer has edge chipping or damage by the continuity of edge brightness and the density of abnormal reflection points in the dark field image.

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