A wireless device and method of measuring the gap between a focus ring and the edge of a wafer

Abstract

The application provides a wafer focusing ring gap measuring device (1), which comprises a wafer and is used for measuring the gap between the wafer and a focusing ring, and is characterized in that at least the following devices are arranged on the wafer: a gap measuring module (4) for measuring the gap distance between the wafer edge and the focusing ring; a gap collecting module (5) connected with the gap measuring module (4) and used for collecting the measurement information of the gap measuring module (4) and transmitting the measurement information to an upper computer. The application also provides a corresponding measuring system and a measuring method. Through the application, the in-situ measurement of the wafer and the focusing ring gap can be realized, the calibration positioning cavity is avoided, and space is saved; and real-time in-situ detection can be realized.

Description

Technical Field

[0001] This invention belongs to the field of semiconductor equipment, specifically relating to the field of semiconductor equipment testing, and particularly to a wireless wafer testing device and method integrating an optical probe, which can be used to detect the gap between the focusing ring and the edge of the wafer. Background Technology

[0002] In advanced semiconductor integrated circuit manufacturing, hundreds of wafer processing steps are involved. Wafers need to be transferred between various process cavities, such as thin film deposition cavities, etching cavities, and cleaning cavities. Wafers are typically secured by a robotic arm within a focus ring on an electrostatic chuck. The accuracy of the wafer's placement within the focus ring significantly impacts subsequent processing. For example, during plasma etching, uneven gaps between the wafer and the focus ring can lead to uneven electric field distribution, easily causing arcing and damaging both the wafer and the focus ring, or even destroying the electrostatic chuck. In chemical / physical vapor deposition, if the wafer is not placed in the preset position or is tilted, the deposited film thickness will be uneven, affecting device performance. In photolithography, the accuracy of wafer positioning directly determines the success or failure of the lithography process.

[0003] Currently, wafer positioning methods typically employ optical methods. For example, US Patent 9405287B1 discloses a wafer position calibration device and method. This device uses multiple cameras to capture and record images of the wafer edges, compares and analyzes these images to calculate the wafer's concentricity, corrects the wafer position using a robotic arm, and then repeats the image capture and analysis until the wafer moves to the designated position.

[0004] However, existing wafer positioning methods all require adding sensing devices to the outside of the wafer, and they cannot be directly installed in the processing cavity. They require a separate positioning and measurement cavity, where the wafer is calibrated before being transported to the processing cavity by a robotic arm. This process is cumbersome, time-consuming, and inefficient.

[0005] To address the problems with existing measurement devices, a novel device is needed to address the gap between the focusing ring and the wafer edge, along with a measurement method adapted to this device. Summary of the Invention

[0006] To address the issues of bulky wafer positioning systems, long calibration times, and the need for large footprints, this invention provides a wafer focusing ring gap measurement device and method.

[0007] According to one aspect of the present invention, a wafer focusing ring gap measuring device 1 is provided, comprising a wafer and used for measuring the gap between the wafer and the focusing ring, characterized in that at least the following devices are disposed on the wafer: a gap measuring module 4, used for measuring the gap distance between the edge of the wafer and the focusing ring; and a gap acquisition module 5, connected to the gap measuring module 4, used for acquiring the measurement information of the gap measuring module 4 and transmitting the measurement information to a host computer. That is, the gap measuring module 4 and the gap acquisition module 5 are disposed on a wafer or a material similar to a wafer.

[0008] Preferably, the gap measurement module 4 is an optical component that emits incident light to the focusing ring 2 and receives reflected light. The incident light and the reflected light are transmitted to the gap acquisition module 5 as the measurement information.

[0009] Preferably, during the operation of the gap measuring device 1, the light-emitting point of the optical component extends out from between the edge of the wafer and the focusing ring, and moves toward or in the opposite direction to the focusing ring.

[0010] Preferably, the gap measurement module 4 includes at least: a light source 41, for emitting incident light to the focusing ring 2; a photodetector 42, for receiving reflected light returned from the focusing ring 2; and a driving module 47, for providing a driving function to change the focal position of the incident light.

[0011] Preferably, the drive module 47 is used to drive the gap measuring module 4 to move in the direction of the focusing ring or the opposite direction.

[0012] Preferably, the drive module 47 is connected to the light source 41 so that the light source 41 moves in the direction of the focusing ring or in the opposite direction.

[0013] Preferably, the driving module 47 is a galvanometer, which is used to change the lens connected to the light source 41, and to change the position of the lens from the focusing ring or to deform the lens, thereby changing the focal point.

[0014] Preferably, the light source 41 is composed of any one of the following components:

[0015] - A light source.

[0016] - A light source and an optical fiber 44 connected to the light source, the optical fiber 44 being used at least to transmit the incident light and the reflected light. Accordingly, in this case, the driving module is used to drive the optical fiber to move.

[0017] - A light source, an optical fiber 44 connected to the light source and used at least to transmit the incident light and the reflected light, and a lens 45 connected to the optical fiber, the lens 45 being used at least to converge the incident light and collect the reflected light. Accordingly, in this case, the driving module is used to drive the lens 45 to change the position or shape of the lens 45, thereby changing the focal position of the incident light.

[0018] Preferably, the gap measurement module 4 further includes at least a beam splitter 43, which is used to separate the reflected light and collect the reflected light into the photodetector 42.

[0019] Preferably, the light source 41 is any one of LED or laser diode LD; the photodetector 42 is any one of photodiode PD or phototransistor or other photoelectric conversion device; the beam splitter 43 is any one of beam splitting prism, semi-transparent and semi-reflective film, or fiber optic beam splitter; the optical fiber 44 is plastic optical fiber or quartz optical fiber; the lens 45 is aspherical lens or fiber optic lens; and the driving module 47 is any one of stepper motor, piezoelectric driver, or galvanometer, or other driving mechanism capable of generating mechanical displacement.

[0020] Preferably, the gap acquisition module 5 includes at least: a processing module 6 for processing the acquired measurement information; and a transmission module 7 connected to the processing module and used to transmit the acquired measurement information to a host computer.

[0021] Preferably, the processing module 6 includes at least the following modules: a microprocessor or other semiconductor device capable of digital signal processing; an optoelectronic control module connected to the microprocessor and used to control at least the light source 41 and the photodetector 42; and an analog-to-digital converter (ADC) connected to the optoelectronic control module and used to convert the analog signal into a digital signal, which is transmitted to the host computer through the transmission module 7.

[0022] Preferably, the transmission module 7 is any one of the following wireless communication modules: Bluetooth; ZigBee; or Wi-Fi. More preferably, the wireless communication module can also be a module corresponding to a custom communication protocol, all of which are within the scope of protection of this invention.

[0023] Preferably, the gap measurement module 4 and the gap acquisition module 5 are disposed on the wafer in any of the following ways:

[0024] - It is fixed on the upper surface of the wafer;

[0025] - Fixed within a groove formed on the wafer; or

[0026] - Attached and fixed to the outside of the wafer.

[0027] Preferably, when the gap measurement module 4 and the gap acquisition module 5 are fixed in the groove on the wafer, the outer edge of the wafer has an opening, and the opening communicates with the groove, and the incident light emitted by the light source 41 is emitted through the opening.

[0028] Preferably, the light source 41 of the gap measurement module 4 is attached to the outer side of the wafer.

[0029] Preferably, the light source 41 is retracted into the wafer via the outer edge opening of the wafer through the driving module 47, or moved towards the focusing ring through the driving module 47.

[0030] Preferably, the gap measuring module 4, except for the light source 41, has other components fixed to the upper surface of the wafer or in a groove formed on the wafer.

[0031] Preferably, the number of gap measuring modules 4 is two or more, for example, any number can be selected from 2 to 8.

[0032] According to another aspect of the present invention, a measurement system is also provided for measuring the gap between a wafer and a focusing ring, comprising at least a host computer 11 and the aforementioned wafer focusing ring gap measuring device 1. When the measurement system is in operation, the wafer focusing ring gap measuring device 1 is placed and adsorbed onto an electrostatic chuck 3 adapted to the focusing ring 2.

[0033] According to another aspect of the present invention, a measurement method based on the above-described wafer focusing ring gap measuring device 1 is also provided, which is used to measure the gap between the wafer and the focusing ring, and includes the following steps:

[0034] i. The gap measurement module emits incident light and receives reflected light signals, and sends the reflected light signals and the number of steps the gap measurement module has moved to the gap acquisition module;

[0035] ii. The gap measuring module moves to the next measuring position and repeats step i until the gap measuring module has moved to the endpoint;

[0036] iii. The gap acquisition module calculates the gap distance between the wafer and the focusing ring based on the reflected light signal and the step count information.

[0037] Preferably, in step iii, the gap distance is: the initial position D0 of the gap measurement module plus the number of moving steps n * step length d corresponding to the extreme value of the reflected light signal, i.e., D0 + nd.

[0038] Preferably, before step i, the following steps are also included: the wafer focusing ring gap measuring device 1 performs a self-test, and the gap measuring module moves to the initial position D0.

[0039] Compared to existing solutions, this invention integrates the wafer positioning device onto the wafer, enabling in-situ measurement of the gap between the wafer and the focusing ring. This eliminates the need for a calibration positioning cavity, saving space. Real-time in-situ detection is possible. A single gap measurement determines the positional correspondence between the wafer and the focusing ring, eliminating the need for manual calibration of each wafer and saving time on the production line. The method of determining the focusing ring position using optical signal extrema is unaffected by the focusing ring material and can be used for various materials. The use of a non-contact optical measurement method avoids direct contact with the focusing ring during measurement, preventing movement of the focusing ring. Attached Figure Description

[0040] Other features, objects, and advantages of the invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0041] Figure 1 A top view schematic diagram of a wafer focusing ring gap measuring device according to a specific embodiment of the present invention is shown;

[0042] Figure 2 A side cross-sectional schematic diagram of a wafer focusing ring gap measuring device according to a specific embodiment of the present invention is shown;

[0043] Figure 3 , Figure 7 The diagram illustrates the principle of a wafer focusing ring gap measuring device according to a specific embodiment of the present invention, specifically a gap measuring module measuring the focusing ring.

[0044] Figure 4 The diagram shows a gap acquisition module and various modules and circuits in a host computer of a wafer focusing ring gap measuring device according to a specific embodiment of the present invention.

[0045] Figure 5 A schematic diagram of the overall operation flow of a wafer focusing ring gap measuring device according to a specific embodiment of the present invention is shown.

[0046] Figure 6 A schematic diagram of the measurement operation process of a wafer focusing ring gap measuring device according to a specific embodiment of the present invention is shown; and

[0047] Figure 8 The diagram illustrates measurement information obtained during the operation of a wafer focusing ring gap measuring device according to a specific embodiment of the present invention.

[0048] Label Explanation:

[0049] 1. Wafer focusing ring gap measuring device;

[0050] 2. Focusing ring;

[0051] 3. Electrostatic chuck;

[0052] 4. Measurement module;

[0053] 41. Light source; 42. Detector; 43. Beam splitter;

[0054] 44. Optical fiber; 45. Lens; 46. Focal point; 47. Drive module;

[0055] 5. Data Acquisition Module;

[0056] 6. Processing module;

[0057] 7. Transmission module;

[0058] 8. Power supply module;

[0059] 11. Host computer;

[0060] 111. I / O module; 112. Processing module; 113. Power supply module. Detailed Implementation

[0061] Those skilled in the art will understand that, in a preferred embodiment, the invention includes the following unique technical features:

[0062] Figure 1 A top view schematic diagram of the wafer focusing ring gap measuring device 1, focusing ring 2, and electrostatic chuck 3 is drawn. Correspondingly, Figure 2 The wafer focusing ring gap measuring device 1, focusing ring 2, and electrostatic chuck 3 are shown in side cross-sectional views. Figure 1 , Figure 2 As shown, the wafer focusing ring gap measuring device 1 provided by the present invention is placed on the focusing ring 2 and the electrostatic chuck 3. During the semiconductor manufacturing process, the wafer to be processed is attracted and fixed by the electrostatic chuck 3, and a gap exists between the wafer and the focusing ring 2, for example... Figure 2The gap shown is significant. When the wafer center and the focusing ring center are not aligned, the gap between the wafer and the focusing ring 2 is not spatially uniform, resulting in uneven distribution of the applied electric field during processes such as plasma etching. This can easily lead to arcing, damaging the wafer, focusing ring, and electrostatic chuck. Therefore, the accuracy of wafer positioning is crucial for semiconductor processing.

[0063] This invention integrates a gap measuring device onto a wafer, forming a wafer focusing ring gap measuring device 1. This wafer focusing ring gap measuring device 1 preferably has the same dimensions as the wafer processed during semiconductor manufacturing. By placing it at the wafer pre-processing position, in-situ detection and acquisition of wafer position information can be achieved. In a preferred embodiment, in... Figure 2 In this embodiment, the sheet-like object below the measurement module 4 is the wafer described in this invention. In another variation, the wafer can be replaced by an object with the same appearance as the wafer, and the gap measuring device can be integrated into this object, thereby forming an alternative wafer focusing ring gap measuring device 1. Preferably, the wafer focusing ring gap measuring device 1 has a gap measuring module 4 and a data acquisition module 5, which are responsible for measuring the gap and acquiring data, respectively.

[0064] Figure 3 A schematic diagram of the gap measurement module 4 measuring the focusing ring 2 is shown. The gap measurement module 4 includes a light source 41, a detector 42, a beam splitter 43, an optical fiber 44, a lens 45, and a driving module 47. The incident light emitted from the light source 41 is converged at the focal point 46 by the beam splitter 43, optical fiber 44, and lens 45, finally illuminating the focusing ring 2 and reflecting back. It then passes through the lens 45, optical fiber 44, and beam splitter 43 again, illuminating the detector 42. The detector 42 receives the optical signal value and transmits it to the acquisition module 5 for data processing. Since the gap width is unknown, the focal point of the light spot is not necessarily on the focusing ring 2. The driving module 47 can drive the measurement module 4 to translate radially along the wafer, adjusting the position of the focal point 46. When it is exactly on the focusing ring 2, the reflected light signal has an extreme value, i.e., the value of the detector 42 is an extreme value. Therefore, the position of the focusing ring can be determined by the number of steps the driving module moves and the corresponding detector value. Furthermore, the width of the gap between the wafer and the focusing ring can be derived from the known step size and initial position of the driving module.

[0065] Further, refer to Figure 3 As will be understood by those skilled in the art in the illustrated embodiment, during the operation of the gap measuring device 1, the light focus of the optical component is between the edge of the wafer and the focusing ring. Further, refer to... Figure 6 As will be understood by those skilled in the art in the illustrated embodiment, the focal point moves toward or in the opposite direction of the focusing ring through the operation of the driving module.

[0066] The drive module can use a stepper motor or piezoelectric driver to move the entire measurement module, or just move the optical fiber and lens.

[0067] The drive module can also use a galvanometer. In this case, other components remain stationary, and only the lens moves or deforms to change the lens focus, thus achieving the same effect as the translation drive module.

[0068] Further reference Figure 3 , Figure 7 As will be understood by those skilled in the art, the light source 41 provided by the present invention can be implemented in different variations based on different implementation methods, thereby allowing the light source to emit the incident light. In one variation, the light source 41 is a simple light source, such as an LED light source, through which the incident light is emitted towards the focusing ring. In another variation, the light source 41 consists of a light source and an optical fiber connecting the light source. In such a variation, the incident light is preferentially emitted towards the focusing ring through the end of the optical fiber, further referring to... Figure 1 , Figure 2 , Figure 3 as well as Figure 6 , Figure 7 In the illustrated embodiment, the driving module preferably drives the optical fiber to move, thereby changing... Figure 3 The position of the focal point is indicated, thereby obtaining different reflected light signal values. Furthermore, in such a variation, other components besides the optical fiber, such as the gap acquisition module 5, can be fixed and do not need to be moved by the drive module; these variations are all within the scope of protection of this invention. Furthermore, in such a variation, the end of the optical fiber can be positioned within a laterally shaped opening on the outer edge of the wafer, such that the end of the optical fiber is within the wafer, with the wafer on both the top and bottom of the optical fiber, and the optical fiber can move inward or outward within the opening, i.e., the end of the optical fiber moves towards or away from the focusing ring. Further, the incident light emitted by the optical fiber is emitted through the opening. In another variation, the light source 41 consists of a light source, an optical fiber connected to the light source, and a lens 45 connected to the optical fiber. In this case, the lens 45 ultimately emits incident light, and the drive module drives the lens 45 to change position. Preferably, the lens 45 can be positioned within a laterally shaped opening on the outer edge of the wafer.

[0069] Figure 4 This is a schematic diagram of the gap acquisition module 5 and the various modules and circuits within the host computer 11.

[0070] The gap acquisition module 5 contains circuitry for acquiring the output of the measurement module 4, and, if necessary, providing any input signals required to drive the measurement module 4, such as a microprocessor, amplifier, analog-to-digital converter (ADC), current source, and filter.

[0071] The processing module 6 acquires and stores the data from the detector 42 and the drive module 47 obtained by the gap measurement module 4. The processing module 6 may contain calibration coefficients from the measurement module 4 to calibrate the acquired gap data. The memory of the processing module 6 may be RAM, DRAM, ROM, SSD, flash, EPROM, EEPROM, etc.

[0072] The transmission module 7 sends the gap information from the processing module 6 to the input / output (I / O) module 111 of the host computer 11, and receives any control signals from the I / O module 111 of the host computer 11. The communication connection between modules uses a wireless communication module (such as infrared, Bluetooth, ZigBee, Wi-Fi, etc.), or can communicate directly through an inductive coil.

[0073] The power supply module 8 provides power to all components of the wafer focusing ring gap measurement device 1, and can be a rechargeable lithium battery. The power supply module 8 may include a wired charging module and a wireless charging module, which are interconnected with the power supply module 113 of the host computer 11.

[0074] The host computer 11 can be any microprocessor, such as a computer, a handheld computer (PDA), or a PLC system built with a microcontroller. The host computer 11 includes an I / O module 111, a processing module 112, and a power supply module 113. The I / O module 111 can use a wired communication module, a wireless communication module, or it can directly communicate with the transmission module 7 of the wafer focusing ring gap measuring device 1 via an inductive induction coil. The I / O module 111 may also include a display, keyboard, or mouse.

[0075] The substrate of the wafer focusing ring gap measuring device 1 is preferably a silicon wafer, but it can also be made of other materials that can be used in the manufacture of integrated circuits, such as gallium arsenide, glass, ceramic, nitride, or carbide. The diameter of the substrate is preferably 200 mm or 300 mm to conform to current wafer sizes, but it can have any diameter or arbitrary shape.

[0076] Components on the gap measuring device 1, such as the gap measuring module 4 and the gap acquisition module 5, can be placed above the wafer or embedded in a pre-processed blind slot on the wafer, making it more advantageous to meet the wafer transfer height requirements of semiconductor processes. Furthermore, those skilled in the art will understand that when the gap measuring module 4 is embedded in the blind slot, considering the emission and reception of incident and reflected light, a slot can be cut on the outer side of the wafer at a position corresponding to the measuring module 4, allowing the gap measuring module 4 to emit or receive light beams externally; this is all within the scope of this invention. Furthermore, grooves can be etched on the wafer, the depth of which corresponds to the depth of each component of the wafer focusing ring gap measuring device 1 (e.g., Figure 1 , Figure 2 The height of the wafer focusing ring gap measuring device 1 is adapted to the height of the wafer, so that the overall height of the device does not exceed the height of the wafer, which better meets the requirements of semiconductor processing technology. Furthermore, in another variation, the gap measuring module 4 and other devices are attached to the outside of the wafer, i.e., facing the gap being measured and facing the focusing ring, which is also within the scope of protection of this invention.

[0077] The number of gap measuring modules 4 is not limited to four; higher positioning accuracy can be obtained by increasing the number. In another variation, the number of gap measuring modules 4 can be reduced, for example, by using two or three measuring modules 4 to achieve the gap measurement described in this invention.

[0078] Figures 5 to 8 A schematic diagram of the operation of the gap measuring device 1 provided by the present invention is shown. Specifically, Figure 5 This is a schematic diagram of the overall operation of the gap measuring device 1. First, in step S101, the gap measuring device is started by turning on its power.

[0079] Then proceed to step S102, where the robotic arm transfers the gap measuring device 1 to the electrostatic chuck.

[0080] Then proceed to step S103, where the host computer sends a wireless signal to notify the gap measuring device 1 to start the measurement and wait for the test results.

[0081] Then proceed to step S104, after the gap measuring device 1 completes the measurement, it wirelessly sends the result to the host computer.

[0082] Then proceed to step S105, the test is completed, the robotic arm retrieves the gap measuring device 1 and shuts it down.

[0083] Figure 6 This is a schematic diagram of the measurement operation process of the gap measuring device 1, and refers to... Figure 7 , Figure 8 The following explanation is provided.

[0084] First, proceed to step S201. After starting the test, the program performs a self-check, and the driver module returns to the zero position D0.

[0085] Then proceed to step S202 to determine whether the drive module has reached the endpoint.

[0086] If not, proceed to step S203, where the light source 41 emits a modulated light signal, the detector 42 receives the light signal intensity data and sends it along with the step size of the drive module to the acquisition module 5; the drive module moves forward one step, preferably with a step size of d. Then return to step S202.

[0087] If so, proceed to step S204, where the light source 41 emits a modulated light signal, the detector 42 receives the light signal intensity data and sends it along with the step count of the drive module to the acquisition module 5; the drive module returns to the zero position D0.

[0088] Then proceed to step S205. Based on the previously obtained detector data and drive module step size data, gap acquisition module 5 calculates the number of steps n that the drive module moves forward corresponding to the point where the detector value is maximum. The gap value Gap = D0 + nd is obtained from the known step size d.

[0089] Furthermore, those skilled in the art will understand that in the above processing, the measured light intensity value and the number of driving module steps in the next step are sent to the acquisition module for storage. After entering S205, the maximum value and the corresponding number of driving module steps n are found based on the light intensity data, thereby obtaining the gap distance value Gap.

[0090] In this field, the initial position D0 of the gap measurement module 4 preferably refers to the distance between the focal point of the incident light and the edge of the wafer. Each time, the driver moves the measurement module one step, with a step size of d. A total of N steps are taken, and each step generates a light signal, such as light intensity. The number of steps n corresponding to the maximum light intensity can be obtained from the light intensity data. Because the focal point of the light spot corresponding to the maximum light intensity is on the focusing ring, the gap Gap = D0 + nd. This can be plotted... Figure 8 The curve shown has the horizontal axis representing the number of steps (n) or the distance traveled (nd), and the vertical axis representing the intensity value. Figure 8 The units in the document can be set as needed, and this is all within the scope of protection of this invention.

[0091] Further, refer to Figure 5 as well as Figure 6 , Figure 7 In one variation of the illustrated embodiment, Figure 6The calculation process shown is completed within the host computer; that is, the gap acquisition module 5 directly transmits the measurement information to the host computer, rather than calculating the step size and extreme value information itself. In this variation, the gap acquisition module 5 can preferably not have a storage module. Figure 6 In the illustrated embodiment, preferably, the gap acquisition module 5 includes a storage module for storing multiple measurement information acquired under different time lengths. Furthermore, those skilled in the art will understand that whether the calculation is performed by a host computer or by the gap acquisition module 5, or whether the calculation is synchronous or asynchronous, these variations are all within the scope of protection of this invention.

[0092] Furthermore, in another variation, the role of the host computer can vary depending on the implementation method. For example, the host computer can be the control host in the wafer processing system, or it can be another auxiliary system that works with the control host, or it can be a host in the measurement system provided by the present invention, such as a computer or industrial control computer that receives, displays, or processes wireless data on the gap between the wafer edge and the focusing ring. All these variations are within the scope of protection of the present invention.

[0093] Further, refer to Figure 6 As will be understood by those skilled in the art in the illustrated embodiment, the initial position D0 of the driving module can be at the innermost side of the wafer, i.e., the position furthest from the focusing ring, and closer to the center of the wafer. Figure 6 After the preferred embodiment shown begins execution, the drive module moves the entire gap measuring device 1 towards the edge of the wafer. Conversely, if the initial position D0 of the drive module is close to the edge of the wafer, the drive module moves the entire gap measuring device 1 towards the center of the wafer. That is, the direction of movement of the drive module is selected according to the initial position; if the initial position is at the edge of the wafer, it moves towards the center of the wafer; if the initial position is far from the edge, it moves towards the edge.

[0094] Furthermore, refer to Figure 1 , Figure 2 as well as Figure 6Those skilled in the art will understand that the operating mode of the driving module is adapted to the object it drives. For example, in the preferred embodiment described above, the driving module is used to move the entire gap measuring device 1, thereby causing the light source on the gap measuring device 1 to move, and the light emitted by the light source to move accordingly, thus changing the focal point of the incident light and the intensity signal of the reflected light. In another preferred embodiment, the driving module does not move the entire gap measuring device 1, but only moves the light source, for example, directly moving the light source or moving the optical fiber connected to the light source, thereby changing the emission starting point of the emitted light, thus achieving the effect of moving the entire gap measuring device 1 as described above. In another variation, the driving module is a galvanometer structure, that is, by changing the shape of the lens connected to the light source through the galvanometer structure, the focal point of the incident light is changed. These variations of the driving module are all within the protection scope of this invention.

[0095] Those skilled in the art will understand that the gap between a 12-inch wafer and the focusing ring is typically between 0 and 3 mm. In a preferred embodiment, this technical solution sets the zero point of the driving module at the position where the focal point 46 coincides with the edge of the wafer, at which point D0 is zero; the forward endpoint of the driving module is 3 mm. The focal length of the lens is greater than 3 mm to ensure that the measurement module does not extend beyond the edge of the wafer under the drive of the driving module.

[0096] Those skilled in the art will understand that, in the preferred embodiments provided by the present invention, the wafer focusing ring gap measuring device and method utilize an optical gap measuring device integrated on the wafer. By moving the position of the optical gap measuring device or changing the position of the optical gap measuring device to detect the light focal point, the light signal and position information reflected back by the focusing ring are obtained, and the gap between the wafer and the focusing ring is then deduced.

[0097] The gap measurement device is integrated on the wafer and includes a gap measurement module, a data acquisition module, a processing module, a transmission module, and a power supply module.

[0098] The gap measurement module is used to measure the gap between the wafer and the focusing ring, and includes a light source, a photodetector, a beam splitter, an optical fiber, a lens, and a driving module. The light source is preferably an LED, a laser diode (LD), or other similar light source. The photodetector can be a photodiode (PD) or a phototransistor, or other similar photodetector device. The beam splitter separates the light emitted from the light source (i.e., the incident light) from the light reflected back from the focusing ring, allowing the incident light to illuminate the focusing ring and collecting the reflected light onto the photodetector device. The beam splitter can preferably be a beam splitter prism, a semi-transparent and semi-reflective film, or an optical fiber beam splitter; other types of optical beam splitters can also be used, all within the scope of this invention. The optical fiber is used to transmit the incident and reflected light; in a preferred embodiment, it can be implemented using optical guiding devices such as plastic optical fiber or quartz optical fiber. The lens is used to converge the incident light and collect the reflected light, and can be an aspherical lens, an optical fiber lens, etc. The driving module is used to drive the measurement module and can be implemented using a stepper motor, a piezoelectric driver, a galvanometer, etc.

[0099] The gap acquisition module is used to acquire information from the measurement module and includes a processing module, a transmission module, and a power supply module. That is, the signals from the measurement module are received by the gap acquisition module and then processed by the processing module.

[0100] The processing module is used to store and process the acquired location information. In a preferred embodiment, it includes a microprocessor, an optoelectronic control module, an analog-to-digital converter (ADC), and memory such as RAM, DRAM, ROM, SSD, flash, EPROM, EEPROM, etc.

[0101] The transmission module is used to transmit the location information collected by the acquisition device to the host computer, and includes a wireless communication module (such as Bluetooth, ZigBee, Wi-Fi, etc.).

[0102] The power supply module provides power to the measuring device, and preferably includes a rechargeable lithium battery, a wired charging module, or a wireless charging module. Specifically, the power supply module can power the gap measuring device 4 and the gap acquisition device 5, which are all within the protection scope of this invention.

[0103] Furthermore, those skilled in the art will understand that the photoelectric control module sends commands to the light source in the measurement module to emit specific light pulses or modulated light signals, and also controls the activation and deactivation of the photodetector in the measurement module, as well as the selection of the receiving mode. The photoelectric control module is preferably used to control the brightness of the light source, the response of the receiver, etc.

[0104] The process of measuring the gap is as follows: Power is turned on, and the robotic arm moves the measuring device onto the electrostatic chuck and positions it within the focusing ring. The microprocessor in the processing module runs its built-in program, activates the wireless communication module, and upon receiving the start measurement command from the host computer, activates the photoelectric control module. This drives the light source in the measurement module to emit a modulated light signal (which can be a pulse, frequency-modulated, or amplitude-modulated light signal). The light signal enters the beam splitter and, preferably, travels through an optical fiber and a lens to the focusing ring to be measured, is reflected back to the photodetector. The photodetector transmits the measured light signal (i.e., the reflected light) back to the processing module in the gap acquisition module for processing and storage, completing one light signal detection. Then, the processing module sends a command to the drive module in the gap measurement module. The drive module operates and moves the position of the gap measuring device or changes the focal point of the lens, performing another light signal detection. This cycle continues until the drive module moves the gap measuring device to all positions, i.e., all positions are measured. Furthermore, the processing module establishes a one-to-one correspondence between the measured light signal and the movement step size; the extreme values ​​of the light signal correspond to the positions of the focusing ring. The gap width between the wafer and the focusing ring can be obtained from the known step size and initial position of the driving module. The acquisition module transmits the gap width result to the host computer via a wireless module. After receiving confirmation, the host computer shuts down and uses a robotic arm to retrieve the measuring device, thus ending the entire measurement process.

[0105] The specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various modifications or variations within the scope of the claims, which do not affect the essence of the present invention.

Claims

1. A wafer focus ring gap measuring device (1) comprising a wafer and for measuring the gap between the edge of the wafer and a focus ring, characterized in that At least the following device is arranged on the wafer: a gap measuring module (4) for measuring the gap distance between the wafer edge and the focus ring; a gap collecting module (5) connected with the gap measuring module (4) for collecting the measurement information of the gap measuring module (4) and transmitting the measurement information to the host computer; wherein the gap measuring module (4) is an optical assembly, at least comprising: a light source component (41) at least for emitting incident light to the focus ring (2); a photodetector (42) at least for receiving reflected light returned from the focus ring (2), the incident light and the reflected light being transmitted as the measurement information to the gap collecting module (5); a driving module (47) at least for providing driving function to make the focus position of the incident light change; the gap collecting module (5) at least comprising: a processing module (6) for processing the collected measurement information; and a wireless transmission module (7) connected with the processing module and for transmitting the collected measurement information to the host computer; when measuring the gap between the wafer edge and the focus ring, the wafer focus ring gap measuring device (1) is placed and adsorbed on the electrostatic chuck (3) compatible with the focus ring (2), and the measuring process comprises the following steps: i. the gap measuring module emits incident light and receives reflected light signal, and sends the reflected light signal and the step information of the movement of the gap measuring module to the gap collecting module; ii. the gap measuring module moves to the next measurement position and repeats step i until the gap measuring module has moved to the end point; iii. the gap collecting module calculates the gap distance between the wafer and the focus ring according to the reflected light signal and the step information.

2. The gap measuring device (1) according to claim 1, characterized in that During the working process of the gap measuring device (1), the focus position of the incident light is between the edge of the wafer and the focus ring and moves towards the focus ring or in the opposite direction.

3. The gap measuring device (1) according to claim 1, characterized in that The driving module (47) is used to drive the gap measuring module (4) to move towards the focus ring or in the opposite direction.

4. The gap measuring device (1) according to claim 1, characterized in that The driving module (47) is connected with the light source component (41) to make the light source component (41) move towards the focus ring or in the opposite direction.

5. The gap measuring device (1) according to claim 1, characterized in that The driving module (47) is a galvanometer for changing the lens connected with the light source component (41) and making the position of the lens change or making the lens deform, so as to change the focus.

6. The gap measuring device (1) according to any one of claims 1 to 5, characterized in that The light source component (41) is composed of any one of the following components: - a light source; - a light source and an optical fiber (44) connected with the light source, the optical fiber (44) being at least for transmitting the incident light and the reflected light to the outside; - a light source, an optical fiber (44) connected with the light source and at least for transmitting the incident light and the reflected light to the outside, and a lens (45) connected with the optical fiber, the lens (45) being at least for converging the incident light and collecting the reflected light.

7. The gap measuring device (1) according to claim 5, characterized in that The gap measuring module (4) further comprises at least a beam splitter (43) for separating the reflected light and collecting the reflected light to the photodetector (42).

8. The gap measuring device (1) according to claim 7, characterized in that The light source (41) is any one of LED or laser diode (LD); the photodetector (42) is any one of photodiode (PD) or phototriode; the beam splitter (43) is any one of beam splitter prism, half-transmission half-reflection sheet, fiber beam splitter; the optical fiber (44) is any one of plastic optical fiber or quartz optical fiber; the lens (45) is any one of aspheric lens or fiber lens; the driving module (47) is any one of stepper motor, piezoelectric driver or galvanometer.

9. The gap measuring device (1) according to claim 1, characterized in that The processing module (6) comprises at least the following modules: a microprocessor; a photoelectric control module connected to the microprocessor and used for controlling the light source (41) and / or the photodetector (42); an analog-to-digital converter (ADC) connected to the photoelectric control module and used for converting analog signals to digital signals, which are transmitted to the host computer through the wireless transmission module (7).

10. The gap measuring device (1) according to claim 1 or 9, characterized in that The wireless transmission module (7) is any one of the following wireless communication modules: Bluetooth; ZigBee; or WiFi.

11. The gap measuring device (1) according to any one of claims 1 to 5, characterized in that The gap measuring module (4) and the gap collecting module (5) are arranged on the wafer in any one of the following ways: fixed on the upper surface of the wafer; fixed in the groove on the wafer; or fixed on the outer side of the wafer.

12. The gap measuring device (1) according to claim 11, characterized in that When the gap measuring module (4) and the gap collecting module (5) are fixed in the groove on the wafer, the outer edge of the wafer has an opening communicating with the groove, and the incident light emitted by the light source (41) is emitted through the opening.

13. The gap measuring device (1) according to claim 11, characterized in that The light source (41) of the gap measuring module (4) is attached to the outer side of the wafer.

14. The gap measuring device (1) according to claim 13, characterized in that The light source (41) is retracted into the wafer through the opening of the outer edge of the wafer by the driving module (47), or moved towards the focusing ring by the driving module (47).

15. The gap measuring device (1) according to claim 13 or 14, characterized in that The components of the gap measuring module (4) except the light source (41) are fixed on the upper surface of the wafer or in the groove on the wafer.

16. The gap measuring device (1) according to any one of claims 1 to 5, characterized in that The number of the gap measuring modules (4) is two or more.

17. A measuring system for measuring the gap between the edge of a wafer and a focusing ring, comprising at least a host computer (11) and a wafer-focusing-ring-gap measuring device (1) according to any one of claims 1 to 16.

18. A measuring method based on the wafer-focusing-ring-gap measuring device (1) according to any one of claims 1 to 16, for measuring the gap between the edge of a wafer and a focusing ring.

19. The method of measuring of claim 18, wherein, In the step iii, the gap distance is the initial position D0 of the gap measuring module plus the moving step number n*step length d corresponding to the extreme value of the reflected light signal, i.e. D0+nd.

20. The measuring method according to claim 18 or 19, characterized in that, Before the step i, further comprising the following steps: the wafer focus ring gap measurement device (1) carries out self-checking, and the gap measurement module moves to an initial position D0.

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