Wafer vacuum chuck calibration method and device, wafer detection equipment and storage medium

Abstract

The invention discloses a wafer vacuum chuck calibration method and device, wafer detection equipment and a storage medium. The wafer vacuum chuck calibration method comprises the steps that in the vacuum breaking process of a wafer vacuum chuck, a negative pressure switch is controlled to be in an off state, a positive pressure switch is controlled to be in an on state, and a first time point when the positive pressure switch is in the on state and a second time point when the air pressure of the chuck reaches a first air pressure value are obtained, according to the first time point and the second time point, determining the time duration of positive pressure conduction; and obtaining a third time point when the air pressure of the suction cup reaches a second air pressure value after the air pressure of the suction cup passes through the zero point, and obtaining a third air pressure value after the vacuum breaking of the wafer vacuum suction cup after the third time point, so as to determine that the vacuum breaking of the wafer vacuum suction cup reaches a safe air pressure threshold value based on the third air pressure value. The vacuum breaking speed of the wafer vacuum chuck is increased, and the material safety is improved.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and in particular to a wafer vacuum chuck calibration method, device, wafer detection equipment and storage medium. Background Art

[0002] Wafer inspection equipment generally uses a precision motion stage as the main inspection unit. The precision motion stage carries the silicon wafer to the designated inspection station for the corresponding inspection process. A wafer vacuum chuck is included on the top of the precision motion stage. The wafer vacuum chuck quickly extracts the air on the surface of the wafer vacuum chuck by opening or closing the vacuum valve, and uses atmospheric pressure to precisely and flatly adsorb the silicon wafer on the upper surface of the wafer vacuum chuck, ensuring that the silicon wafer and the precision motion stage remain relatively still during the high-speed movement of the precision motion stage, so as to obtain better inspection results.

[0003] At present, in consideration of factors such as increasing the utilization rate of wafer inspection equipment and saving costs, the same vacuum switching method is often used directly on the incoming wafer vacuum chucks. However, due to the high requirements on the manufacturing process of the wafer vacuum chucks, the different sizes of the pores of different wafer vacuum chucks often lead to large differences in the vacuum breaking time of the wafer vacuum chucks. This phenomenon may affect the output of WPH (wafer per hour) per hour, and in serious cases, there may be a safety risk of damaging the wafer materials. Summary of the invention

[0004] The present invention provides a wafer vacuum chuck calibration method, device, wafer detection equipment and storage medium to solve the problem that the vacuum breaking of the wafer vacuum chuck is currently restricted by the manufacturing process requirements, which may affect the wafer production output and material safety risks.

[0005] According to one aspect of the present invention, a wafer vacuum chuck calibration method is provided, the wafer vacuum chuck calibration method comprising:

[0006] During the vacuum breaking process of the wafer vacuum chuck, the negative pressure switch is controlled to be in an open state and the positive pressure switch is controlled to be in a closed state, a first time point when the positive pressure switch is in the closed state and a second time point when the air pressure of the chuck reaches a first air pressure value are obtained, and the positive pressure time length is determined according to the first time point and the second time point;

[0007] Obtain a third time point when the air pressure of the suction cup reaches a second air pressure value after the air pressure of the suction cup crosses the zero point, and obtain a third air pressure value after the vacuum of the wafer suction cup is broken after the third time point, so as to determine whether the vacuum of the wafer suction cup is broken and reaches a safe air pressure threshold based on the third air pressure value.

[0008] According to another aspect of the present invention, a wafer vacuum chuck calibration device is provided, the wafer vacuum chuck calibration device comprising:

[0009] a positive pressure time length determination module, used to control the negative pressure switch to be in an open state and the positive pressure switch to be in a closed state during the vacuum breaking process of the wafer vacuum chuck, obtain a first time point when the positive pressure switch is in a closed state and a second time point when the air pressure of the chuck reaches a first air pressure value, and determine the positive pressure time length according to the first time point and the second time point;

[0010] The air pressure safety threshold determination module is used to execute acquisition of a third time point when the air pressure of the suction cup reaches a second air pressure value after the air pressure of the suction cup crosses the zero point, and to obtain a third air pressure value after the vacuum of the wafer suction cup is broken after the third time point, so as to determine, based on the third air pressure value, that the vacuum of the wafer suction cup is broken and reaches a safety air pressure threshold.

[0011] According to another aspect of the present invention, there is provided a wafer inspection device, the wafer inspection device comprising:

[0012] at least one processor; and,

[0013] a memory communicatively connected to the at least one processor; wherein,

[0014] The memory stores a computer program that can be executed by the at least one processor, and the computer program is executed by the at least one processor so that the at least one processor can execute the wafer vacuum chuck calibration method described in any embodiment of the present invention.

[0015] According to another aspect of the present invention, a computer-readable storage medium is provided, wherein the computer-readable storage medium stores computer instructions, and the computer instructions are used to enable a processor to implement the wafer vacuum chuck calibration method described in any embodiment of the present invention when executed.

[0016] The technical solution of the embodiment of the present invention is to control the negative pressure switch to be in an open state and the positive pressure switch to be in a closed state during the process of breaking the vacuum of the wafer vacuum chuck, obtain the first time point when the positive pressure switch is in a closed state and the second time point when the air pressure of the chuck reaches the first air pressure value, and determine the length of the positive pressure time according to the first time point and the second time point; obtain the third time point when the air pressure of the chuck reaches the second air pressure value after the air pressure of the chuck crosses the zero point, and obtain the third air pressure value after the vacuum of the wafer vacuum chuck is broken after the third time point, so as to determine that the vacuum of the wafer vacuum chuck reaches the safe air pressure threshold based on the third air pressure value. The present invention solves the problem that the vacuum breaking of the wafer vacuum chuck is currently limited by the manufacturing process requirements, which may affect the wafer production volume and material safety risks, and realizes the improvement of the vacuum breaking speed of the wafer vacuum chuck and improves material safety.

[0017] It should be understood that the contents described in this section are not intended to identify the key or important features of the embodiments of the present invention, nor are they intended to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0019] Figure 1 is a flow chart of a wafer vacuum chuck calibration method provided in an embodiment of the present invention;

[0020] Figure 2 It is a schematic diagram of the principle of a positive pressure switch and a negative pressure switch when a wafer vacuum chuck is in an adsorption state according to an embodiment of the present invention;

[0021] Figure 3 is a schematic diagram of actual air pressure changes when a wafer vacuum chuck breaks vacuum according to an embodiment of the present invention;

[0022] Figure 4 is a schematic diagram of negative pressure delay decision for breaking vacuum of a wafer vacuum chuck provided in an embodiment of the present invention;

[0023] Figure 5 is a structural schematic diagram of a wafer vacuum chuck calibration device provided according to an embodiment of the present invention;

[0024] Figure 6 It is a structural schematic diagram of a wafer detection device for implementing the wafer vacuum chuck calibration method according to an embodiment of the present invention. DETAILED DESCRIPTION

[0025] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments 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 creative work should fall within the scope of protection of the present invention.

[0026] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0027] Figure 1 A flow chart of a wafer vacuum chuck calibration method is provided for an embodiment of the present invention. This embodiment is applicable to the situation where a wafer vacuum chuck is quickly broken and material safety is ensured. The wafer vacuum chuck calibration method can be performed by a wafer vacuum chuck calibration device. The wafer vacuum chuck calibration device can be implemented in the form of hardware and / or software. The wafer vacuum chuck calibration device can be configured in a wafer detection device. Figure 1 As shown, the wafer vacuum chuck calibration method includes:

[0028] S110. During the process of breaking the vacuum of the wafer vacuum suction cup, the negative pressure switch is controlled to be in an open state and the positive pressure switch is controlled to be in a closed state. The first time point when the positive pressure switch is in the closed state and the second time point when the air pressure of the suction cup reaches the first air pressure value are obtained, and the length of time for the positive pressure is determined according to the first time point and the second time point.

[0029] During the vacuum breaking process of the wafer vacuum chuck, positive pressure is introduced into the wafer vacuum chuck to accelerate the elimination of negative pressure. However, as the time of introducing positive pressure increases, the positive pressure will overshoot. If the given time of positive pressure is not controlled, the problem of wafer blowing will further occur. In severe cases, it may even directly cause the wafer to blow up, or cause a small displacement of the wafer silicon wafer, thereby affecting the wafer inspection results. To solve the above problems, during the vacuum breaking process of the wafer vacuum chuck, the appropriate positive pressure opening time is calibrated to improve the vacuum breaking speed of the wafer vacuum chuck.

[0030] For details, see Figure 2 As shown, the wafer vacuum suction cup 5 is in the adsorption state, the positive pressure switch 4 is in the open state, and the negative pressure switch 3 is in the closed state. The positive pressure switch 4 is arranged on the positive pressure air pipe 2, and the negative pressure switch 3 is arranged on the negative pressure air pipe 1. Figure 3 As shown in Table 1 below, the yellow curve is the change of the air pressure analog quantity during the vacuum breaking process of the wafer vacuum chuck 5, the purple line is the action of the negative pressure switch 3 (specifically: low level is closed state = 1, high level is open state = 0), and the orange line is the positive pressure switch 4 (specifically: low level is open state = 0, high level is closed state = 1). According to the analog quantity conversion result, the Y2 horizontal line is the scale line of the actual air pressure of the wafer vacuum chuck breaking the vacuum of 0Kpa. Figure 3 It can be seen that before the negative pressure switch 3 is in the off state, the pressure value of the wafer vacuum suction cup adsorbing the silicon wafer is converted to about -80Kpa.

[0031] Table 1 Relationship between positive pressure switch, negative pressure switch, differential signal, suction cup air pressure and wafer vacuum suction cup vacuum breaking process

[0032]

[0033] On the basis of the above, continue to see Figure 2 and Figure 3 As shown, the vacuum breaking process of the wafer vacuum chuck is specifically as follows: disconnect the negative pressure switch 3, close the positive pressure switch 4, and in the process of applying positive pressure, the air pressure of the wafer vacuum chuck will rapidly drop from negative pressure and will continue to rise with the opening of the positive pressure air path until the maximum positive pressure value appears before the positive pressure switch 4 is disconnected, and then the air pressure of the wafer vacuum chuck begins to gradually decrease. It is worth noting that the air pressure of the wafer vacuum chuck will drop below 0Kpa, resulting in negative pressure, and then as time goes on, the negative pressure gradually approaches zero.

[0034] It can be understood that in order to speed up the process of eliminating the negative pressure of the suction cup vacuum, the positive pressure switch will be closed while the negative pressure switch is disconnected, so that the first time point when the positive pressure switch is in the closed state can be obtained. The first time point is the moment when the positive pressure switch is closed while the negative pressure switch is disconnected.

[0035] Furthermore, in this embodiment, the air pressure analog quantity is combined with the vacuum breaking process to obtain the actual air pressure, and the air pressure analog quantity in the vacuum breaking process of the wafer vacuum chuck is input into the differential tracker, and the actual change of the air pressure is judged according to the change of the continuous analog quantity. Since the value of the output signal of the differential tracker is dynamically calculated according to the input signal and its change rate, that is, it can be any real number, which depends on the specific characteristics of the input signal and the parameter setting of the tracking differentiator.

[0036] Exemplarily, taking the first differential signal being 1 and the second differential signal being 0 as an example, the time point when the first differential signal is received is taken as the first time point when the positive pressure switch is in a closed state. Continuing to refer to the above Table 1, it can be seen that when the first differential signal is approximately equal to 1, the suction cup air pressure is in a process of rapidly rising to a positive pressure; the time point when the second differential signal is received is taken as the second time point when the air pressure of the suction cup reaches the first air pressure value. The second differential signal is 0, which is the state value corresponding to the suction cup being about bKpa in Table 1. The second time point at this time is the moment when the positive pressure is the largest in the process of breaking the vacuum of the wafer vacuum suction cup.

[0037] Continuing to refer to the above Table 1, it can be seen that the first air pressure value is the maximum positive pressure value that occurs during the vacuum breaking process of the wafer vacuum chuck. The time length from the first time point to the second time point can be used as the positive pressure time length, that is, the appropriate positive pressure time length that can be calibrated.

[0038] In order to ensure that the wafer will not be displaced during the vacuum breaking process and to increase the vacuum breaking speed, during the positive pressure process, the image of the wafer on the wafer vacuum chuck is obtained, and whether the center of the wafer changes is determined based on the image of the wafer. Further, the time point when the center of the wafer does not change and the second differential signal is received is used as the second time point when the air pressure of the chuck reaches the first air pressure value.

[0039] Among them, the image of the silicon wafer on the wafer vacuum chuck can be acquired in real time using an existing image acquisition module. The image acquisition module can be, but is not limited to, a camera and other devices, and this embodiment does not impose any restrictions on this.

[0040] It can be known that whether the center of the silicon wafer changes can be compared with the pre-stored center position of the silicon wafer, or multiple silicon wafer images can be collected and compared one by one to determine whether there is a change. This embodiment does not impose any restrictions on this.

[0041] S120, obtaining a third time point when the air pressure of the suction cup reaches a second air pressure value after the air pressure of the suction cup crosses the zero point, and obtaining a third air pressure value after the vacuum of the wafer suction cup is broken after the third time point, so as to determine whether the vacuum of the wafer suction cup is broken and reaches a safe air pressure threshold based on the third air pressure value.

[0042] On the basis of the above, after the positive pressure switch is disconnected, the pressure of the wafer vacuum chuck begins to gradually decrease. Due to the structure of the wafer vacuum chuck, the pressure curve does not gradually approach 0Kpa, but will directly cross 0Kpa to appear negative pressure. According to the calculation, there may even be negative Kpa of more than ten. If the vacuum is closed according to the previous vacuum breaking method (the first time to 0Kpa after the positive pressure valve is closed) to judge whether the vacuum is closed and give a release signal, the robot arm will take the film. The robot arm is likely to take the film at the lowest point after the air pressure breaks the vacuum. At this time, the robot arm will pull the film with the wafer vacuum chuck (the robot wants to take it away, and the chuck is firmly sucked), causing a greater material safety risk. To solve the above problem, during the process of breaking the vacuum of the wafer vacuum chuck, in view of the situation that the chuck air pressure changes cross 0Kpa many times, a delayed judgment of the air pressure safety threshold solution is adopted to avoid the film taking action due to the reverse lowest point negative pressure after the wafer vacuum chuck breaks the vacuum, thereby improving material safety.

[0043] For details, see Figure 4 As shown in Table 1, during the vacuum breaking process of the wafer vacuum chuck, the chuck air pressure will cross the OKpa point three times. After the chuck air pressure crosses the zero point, taking the second differential signal as 0 as an example, if the received second differential signal is 0, it is determined that the air pressure of the chuck reaches the second air pressure value, and the third time point when the air pressure of the chuck reaches the second air pressure value is determined.

[0044] Among them, the second air pressure value is the suction cup air pressure corresponding to the lowest negative pressure in the process of breaking vacuum of the wafer vacuum suction cup. For example, the second air pressure value can be -cKpa. When the air pressure of the suction cup reaches the second air pressure value or even is less than the second air pressure value, that is, the air pressure of the suction cup is less than or equal to -cKpa, it can be considered that the air pressure of the suction cup is in the state of lowest negative pressure in the process of breaking vacuum of the wafer vacuum suction cup, and then the time point when the lowest negative pressure occurs can be determined, which is the third time point when the air pressure of the suction cup reaches the second air pressure value.

[0045] Further, referring to Table 1 above, it can be seen that if the third differential signal received after the third time point is greater than 0, the third air pressure value after the vacuum chuck of the wafer is broken is obtained; wherein, the absolute value of the second air pressure value -c is greater than the absolute value of the third air pressure value -d.

[0046] It can be understood that the safety air pressure threshold is the air pressure value at which the wafer can be safely removed. It appears after the lowest air pressure point appears during the vacuum breaking process of the circular vacuum suction cup. Then, a judgment is made as to whether the safety air pressure threshold is reached. If the third air pressure value is less than the safety air pressure threshold, it is determined that the wafer vacuum suction cup has broken the vacuum and reached the safety air pressure threshold.

[0047] According to the technical solution of the embodiment of the present invention, during the process of breaking vacuum of the wafer vacuum suction cup, the negative pressure switch is controlled to be in the open state and the positive pressure switch to be in the closed state, and the first time point when the positive pressure switch is in the closed state and the second time point when the air pressure of the suction cup reaches the first air pressure value are obtained, and the positive pressure time length is determined according to the first time point and the second time point, so as to calibrate the appropriate positive pressure time length according to the air pressure analog change curve of the actual wafer vacuum suction cup breaking vacuum and the actual differential tracking curve; further, in view of the situation that the air pressure change of the vacuum breaking suction cup crosses 0Kpa multiple times, a delayed judgment of the air pressure safety threshold value scheme is adopted to obtain the third time point when the air pressure of the suction cup reaches the second air pressure value after the air pressure of the suction cup crosses zero point, and the third air pressure value after the wafer vacuum suction cup breaks the vacuum is obtained after the third time point, so as to determine that the wafer vacuum suction cup breaks the vacuum and reaches the safety air pressure threshold based on the third air pressure value, avoid the reverse lowest point negative pressure after the vacuum breaking to perform the wafer taking action, and improve material safety.

[0048] Based on the same inventive concept, Figure 5 A schematic diagram of the structure of a wafer vacuum chuck calibration device provided by an embodiment of the present invention. Figure 5 As shown, the wafer vacuum chuck calibration device includes:

[0049] The positive pressure time length determination module 210 is used to control the negative pressure switch to be in an open state and the positive pressure switch to be in a closed state during the vacuum breaking process of the wafer vacuum chuck, obtain a first time point when the positive pressure switch is in the closed state and a second time point when the air pressure of the chuck reaches a first air pressure value, and determine the positive pressure time length according to the first time point and the second time point;

[0050] The air pressure safety threshold determination module 220 is used to execute obtaining the third time point when the air pressure of the suction cup reaches the second air pressure value after the air pressure of the suction cup crosses the zero point, and obtain the third air pressure value after the vacuum of the wafer suction cup is broken after the third time point, so as to determine that the vacuum of the wafer suction cup has broken the vacuum and reached the safety air pressure threshold based on the third air pressure value.

[0051] Optionally, the wafer vacuum chuck calibration device further includes:

[0052] A differential signal determination module is used to input the air pressure analog quantity during the vacuum breaking process of the wafer vacuum chuck into a differential tracker, and output a first differential signal and a second differential signal;

[0053] Obtaining a first time point at which the positive pressure switch is in a closed state and a second time point at which the air pressure of the suction cup reaches a first air pressure value is specifically used for:

[0054] The time point when the first differential signal is received is taken as the first time point when the positive pressure switch is in the closed state, and the time point when the second differential signal is received is taken as the second time point when the air pressure of the suction cup reaches the first air pressure value.

[0055] Optionally, the wafer vacuum chuck calibration device further includes:

[0056] A circle center change judgment module is used to obtain a wafer silicon wafer image on a wafer vacuum chuck and determine whether the circle center of the wafer silicon wafer has changed according to the wafer silicon wafer image;

[0057] Obtaining a second time point at which the air pressure of the suction cup reaches the first air pressure value is specifically used for:

[0058] The time point at which the center of the silicon wafer does not change and the second differential signal is received is determined as the second time point at which the air pressure of the suction cup reaches the first air pressure value.

[0059] Optionally, the positive pressure time length is determined according to the first time point and the second time point, specifically for:

[0060] The length of time from the first time point to the second time point is taken as the positive pressure time length.

[0061] Optionally, obtaining a third time point when the air pressure of the suction cup reaches a second air pressure value after the air pressure of the suction cup crosses the zero point is specifically used for:

[0062] After the air pressure of the suction cup crosses the zero point, if a second differential signal is received, it is determined that the air pressure of the suction cup reaches the second air pressure value, and a third time point when the air pressure of the suction cup reaches the second air pressure value is obtained.

[0063] Optionally, the wafer vacuum chuck calibration device further includes:

[0064] A differential signal generating module is used to input the air pressure analog quantity in the process of breaking the vacuum of the wafer vacuum chuck into the differential tracker, and output a third differential signal, and the third differential signal is greater than 0;

[0065] After the third time point, a third air pressure value after the vacuum of the wafer vacuum chuck is broken is obtained, which is specifically used for:

[0066] If the third differential signal received after the third time point is greater than 0, a third air pressure value after the vacuum chuck of the wafer is broken is obtained;

[0067] The absolute value of the second air pressure value is greater than the absolute value of the third air pressure value.

[0068] Optionally, determining that the wafer vacuum chuck breaks vacuum and reaches a safe pressure threshold based on the third air pressure value is specifically used for:

[0069] If the third air pressure value is less than the safety air pressure threshold, it is determined that the vacuum of the wafer vacuum chuck has been broken and has reached the safety air pressure threshold.

[0070] The wafer vacuum chuck calibration device provided in the embodiment of the present invention can execute the wafer vacuum chuck calibration method provided in any embodiment of the present invention, and has the corresponding functional modules and beneficial effects for executing the wafer vacuum chuck calibration method.

[0071] Based on the same inventive concept, Figure 6 FIG. 3 is a schematic diagram showing a structure of a wafer inspection device 310 that can be used to implement an embodiment of the present invention. Figure 6 As shown, the wafer inspection device 310 includes at least one processor 311, and a memory connected to the at least one processor 311, such as a read-only memory (ROM 312), a random access memory (RAM 313), etc., wherein the memory stores a computer program that can be executed by at least one processor, and the processor 311 can perform various appropriate actions and processes according to the computer program stored in the read-only memory (ROM 312) or the computer program loaded from the storage unit 318 to the random access memory (RAM 313). In RAM 313, various programs and data required for the operation of the wafer inspection device 310 can also be stored. The processor 311, ROM 312 and RAM 313 are connected to each other via a bus 314. An I / O (input / output) interface 315 is also connected to the bus 314.

[0072] Multiple components in the wafer inspection device 310 are connected to the I / O interface 315, including: an input unit 316, such as a keyboard, a mouse, etc.; an output unit 317, such as various types of displays, speakers, etc.; a storage unit 318, such as a disk, an optical disk, etc.; and a communication unit 319, such as a network card, a modem, a wireless communication transceiver, etc. The communication unit 319 allows the wafer inspection device 310 to exchange information / data with other devices through a computer network such as the Internet and / or various telecommunication networks.

[0073] The processor 311 may be a variety of general and / or special processing components with processing and computing capabilities. Some examples of the processor 311 include, but are not limited to, a central processing unit (CPU), a graphics processing unit (GPU), various dedicated artificial intelligence (AI) computing chips, various processors running machine learning model algorithms, a digital signal processor (DSP), and any appropriate processor, controller, microcontroller, etc. The processor 311 executes the various methods and processes described above, such as a wafer vacuum chuck calibration method.

[0074] In some embodiments, the wafer vacuum chuck calibration method may be implemented as a computer program, which is tangibly contained in a computer-readable storage medium, such as a storage unit 318. In some embodiments, part or all of the computer program may be loaded and / or installed on the wafer inspection device 310 via the ROM 312 and / or the communication unit 319. When the computer program is loaded into the RAM 313 and executed by the processor 311, one or more steps of the wafer vacuum chuck calibration method described above may be performed. Alternatively, in other embodiments, the processor 311 may be configured to execute the wafer vacuum chuck calibration method in any other appropriate manner (e.g., by means of firmware).

[0075] Various implementations of the systems and techniques described above herein can be implemented in digital electronic circuit systems, integrated circuit systems, field programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), application specific standard products (ASSPs), systems on chips (SOCs), load programmable logic devices (CPLDs), computer hardware, firmware, software, and / or combinations thereof. These various implementations can include: being implemented in one or more computer programs that can be executed and / or interpreted on a programmable system including at least one programmable processor, which can be a special purpose or general purpose programmable processor that can receive data and instructions from a storage system, at least one input device, and at least one output device, and transmit data and instructions to the storage system, the at least one input device, and the at least one output device.

[0076] Computer programs for implementing the methods of the present invention may be written in any combination of one or more programming languages. These computer programs may be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing device, so that when the computer program is executed by the processor, the functions / operations specified in the flow chart and / or block diagram are implemented. The computer program may be executed entirely on the machine, partially on the machine, partially on the machine and partially on a remote machine as a stand-alone software package, or entirely on a remote machine or server.

[0077] In the context of the present invention, a computer-readable storage medium may be a tangible medium that may contain or store a computer program for use by or in combination with an instruction execution system, device or equipment. A computer-readable storage medium may include, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, devices or equipment, or any suitable combination of the foregoing. Alternatively, a computer-readable storage medium may be a machine-readable signal medium. A more specific example of a machine-readable storage medium may include an electrical connection based on one or more lines, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

[0078] To provide interaction with a user, the systems and techniques described herein may be implemented on a wafer inspection device having: a display device (e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor) for displaying information to a user; and a keyboard and a pointing device (e.g., a mouse or a trackball), through which a user can provide input to the wafer inspection device. Other types of devices may also be used to provide interaction with a user; for example, the feedback provided to the user may be any form of sensory feedback (e.g., visual feedback, auditory feedback, or tactile feedback); and input from the user may be received in any form (including acoustic input, voice input, or tactile input).

[0079] The systems and techniques described herein may be implemented in a computing system that includes backend components (e.g., as a data server), or a computing system that includes middleware components (e.g., an application server), or a computing system that includes frontend components (e.g., a user computer with a graphical user interface or a web browser through which a user can interact with implementations of the systems and techniques described herein), or a computing system that includes any combination of such backend components, middleware components, or frontend components. The components of the system may be interconnected by any form or medium of digital data communication (e.g., a communication network). Examples of communication networks include: a local area network (LAN), a wide area network (WAN), a blockchain network, and the Internet.

[0080] A computing system may include a client and a server. The client and the server are generally remote from each other and usually interact through a communication network. The client and server relationship is generated by computer programs running on the corresponding computers and having a client-server relationship with each other. The server may be a cloud server, also known as a cloud computing server or cloud host, which is a host product in the cloud computing service system to solve the defects of difficult management and weak business scalability in traditional physical hosts and VPS services.

[0081] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps described in the present invention can be executed in parallel, sequentially or in different orders, as long as the desired results of the technical solution of the present invention can be achieved, and this document does not limit this.

[0082] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A wafer vacuum chuck calibration method, characterized in that: include: During the vacuum breaking process of the wafer vacuum chuck, the negative pressure switch is controlled to be in an open state and the positive pressure switch is controlled to be in a closed state, a first time point when the positive pressure switch is in the closed state and a second time point when the air pressure of the chuck reaches a first air pressure value are obtained, and the positive pressure time length is determined according to the first time point and the second time point; Obtain a third time point when the air pressure of the suction cup reaches a second air pressure value after crossing the zero point, and obtain a third air pressure value after the vacuum of the wafer suction cup is broken after the third time point, so as to determine whether the vacuum of the wafer suction cup is broken and reaches a safe air pressure threshold based on the third air pressure value.

2. The wafer vacuum chuck calibration method according to claim 1, characterized in that: After controlling the negative pressure switch to be in an open state and the positive pressure switch to be in a closed state, the method further includes: Inputting the air pressure analog quantity during the vacuum breaking process of the wafer vacuum chuck into a differential tracker, and outputting a first differential signal and a second differential signal; Acquiring a first time point at which the positive pressure switch is in a closed state and a second time point at which the air pressure of the suction cup reaches a first air pressure value, comprising: The time point when the first differential signal is received is used as the first time point when the positive pressure switch is in a closed state, and the time point when the second differential signal is received is used as the second time point when the air pressure of the suction cup reaches a first air pressure value.

3. The wafer vacuum chuck calibration method according to claim 2, characterized in that: After outputting the second differential signal, the method further includes: Acquire an image of a silicon wafer on the wafer vacuum chuck, and determine whether the center of the silicon wafer changes according to the image of the silicon wafer; Obtaining a second time point at which the air pressure of the suction cup reaches the first air pressure value, comprising: The time point at which the center of the silicon wafer does not change and the second differential signal is received is determined as the second time point at which the air pressure of the suction cup reaches the first air pressure value.

4. The wafer vacuum chuck calibration method according to claim 1, characterized in that: Determining the positive pressure time length according to the first time point and the second time point includes: The length of time from the first time point to the second time point is taken as the positive pressure time length.

5. The wafer vacuum chuck calibration method according to claim 2, characterized in that: Obtaining a third time point when the air pressure of the suction cup reaches the second air pressure value after the air pressure of the suction cup crosses the zero point, including: After the air pressure of the suction cup crosses the zero point, if the second differential signal is received, it is determined that the air pressure of the suction cup reaches the second air pressure value, and a third time point when the air pressure of the suction cup reaches the second air pressure value is obtained.

6. The wafer vacuum chuck calibration method according to claim 1, characterized in that: After controlling the negative pressure switch to be in an open state and the positive pressure switch to be in a closed state, the method further includes: Inputting the air pressure analog quantity during the vacuum breaking process of the wafer vacuum chuck into a differential tracker, outputting a third differential signal, wherein the third differential signal is greater than 0; Obtaining a third air pressure value after the wafer vacuum chuck breaks vacuum after the third time point, comprises: If the third differential signal received after the third time point is greater than 0, a third air pressure value after the vacuum of the wafer vacuum chuck is broken is obtained; Wherein, the absolute value of the second air pressure value is greater than the absolute value of the third air pressure value.

7. The wafer vacuum chuck calibration method according to claim 1, characterized in that: Determining, based on the third air pressure value, that the wafer vacuum chuck breaks vacuum and reaches a safe air pressure threshold value includes: If the third air pressure value is less than the safety air pressure threshold, it is determined that the vacuum of the wafer vacuum chuck has been broken and has reached the safety air pressure threshold.

8. A wafer vacuum chuck calibration device, characterized in that: include: a positive pressure time length determination module, used to control the negative pressure switch to be in an open state and the positive pressure switch to be in a closed state during the vacuum breaking process of the wafer vacuum chuck, obtain a first time point when the positive pressure switch is in a closed state and a second time point when the air pressure of the chuck reaches a first air pressure value, and determine the positive pressure time length according to the first time point and the second time point; The air pressure safety threshold determination module is used to execute acquisition of a third time point when the air pressure of the suction cup reaches a second air pressure value after the air pressure of the suction cup crosses the zero point, and to obtain a third air pressure value after the vacuum of the wafer suction cup is broken after the third time point, so as to determine, based on the third air pressure value, that the vacuum of the wafer suction cup is broken and reaches a safety air pressure threshold.

9. A wafer inspection device, characterized in that: The wafer inspection equipment comprises: at least one processor; and, a memory communicatively connected to the at least one processor; wherein, The memory stores a computer program executable by the at least one processor, and the computer program is executed by the at least one processor so that the at least one processor can execute the wafer vacuum chuck calibration method according to any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores computer instructions, and the computer instructions are used to enable a processor to implement the wafer vacuum chuck calibration method according to any one of claims 1 to 7 when executed.

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