WO2023216821A1

WO2023216821A1 - Wireless apparatus and measurement method for measuring gap between focus ring and wafer edge

Info

Publication number: WO2023216821A1
Application number: PCT/CN2023/089110
Authority: WO
Inventors: 夏子奂; 刘泽鸿; 邓晨辉; 连超
Original assignee: 上海集迦电子科技有限公司
Priority date: 2022-05-13
Filing date: 2023-04-19
Publication date: 2023-11-16
Also published as: CN114812419A

Abstract

An apparatus (1) for measuring a gap between a wafer and a focus ring. The apparatus comprises a wafer and is used for measuring a gap between the wafer and a focus ring (2), and at least the following apparatuses are arranged on the wafer: a gap measurement module (4), which is used for measuring the gap distance between a wafer edge and the focus ring (2); and a gap collection module (5), which is connected to the gap measurement module (4), and is used for collecting measurement information of the gap measurement module (4), and transmitting the measurement information to an upper computer (11). Further provided are an adaptive measurement system and a measurement method. In-situ measurement of a gap between a wafer and a focus ring can be performed, thereby omitting a calibration positioning cavity, and thus saving space; and real-time in-place detection can be realized.

Description

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

Technical field

The invention belongs to the field of semiconductor equipment detection, and in particular relates to a wireless wafer detection device and method, which can be used to detect the gap between a focus ring and the edge of the wafer.

Background technique

The manufacturing process of advanced semiconductor integrated circuits includes hundreds of wafer processing steps. The wafers need to be transported between various process chambers, such as thin film deposition chambers, etching chambers, and cleaning chambers. The wafer is usually placed in a focus ring on an electrostatic chuck by a robot to be fixed. Whether the wafer can be accurately placed in the center of the focus ring will have a great impact on subsequent processing. For example, during the plasma etching process, the different gaps between the wafer and the focus ring make the electric field distribution uneven, which easily causes arc ignition, causing damage to the wafer and focus ring, and even destroying the electrostatic chuck; During the chemical/physical vapor deposition process, if the wafer is not placed in the preset position or is placed at an angle, the thickness of the film deposited on the wafer will be uneven, which will affect device performance.

US patent US9405287B1 discloses a wafer position calibration equipment and method. The equipment uses multiple cameras to capture and record wafer edge images, compares, analyzes and calculates the concentricity of the wafer, corrects the wafer position through the robot, and then repeats the shooting and analysis until the wafer moves to the designated position.

The existing wafer positioning method requires adding sensing equipment outside the wafer, which cannot be directly installed in the processing chamber. It requires a separate positioning and measurement chamber, which is calibrated and then transported to the processing chamber by a robot. , the steps are cumbersome, the time is long, and the efficiency is low.

Contents of the invention

In order to solve the problems of the wafer positioning system being bulky, occupying space and taking long calibration time, the present invention provides a wafer focusing ring gap measuring device and method.

According to one aspect of the present invention, a wafer focus ring gap measuring device 1 is provided, which includes a wafer and is used to measure the gap between the wafer and the focus ring. It is characterized in that at least the following device is provided on the wafer. The wafer: a gap measurement module 4, which is used to measure the gap distance between the edge of the wafer and the focus ring; a gap acquisition module 5, which is connected to the gap measurement module 4, and is used to collect all The measurement information of the gap measurement module 4 is obtained, and the measurement information is transmitted to the host computer. That is, the above-mentioned gap measurement module 4 and gap collection module 5 are provided on a wafer or a material similar to the wafer.

According to another aspect of the present invention, a measurement system is also provided for measuring the gap between the wafer and the focus ring, which at least includes a host computer 11 and the above-mentioned wafer focus ring gap measurement device 1, where When the measurement system is working, the wafer focus ring gap measurement device 1 is placed and adsorbed on the electrostatic chuck 3 that is compatible with the focus ring 2 .

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

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

ii. The gap measurement module moves to the next measurement position and repeats step i until the gap measurement module has moved to the end point;

iii. The gap acquisition module calculates the gap distance between the wafer and the focus ring based on the reflected light signal and the step number information.

Compared with existing solutions, the present invention integrates the wafer positioning device on the wafer, which can perform in-situ measurement of the gap between the wafer and the focus ring, eliminates the need for a calibration positioning cavity, and saves space; it can achieve real-time In-situ detection: After one gap measurement, the positional relationship between the wafer and the focus ring is determined. There is no need to open the cavity to manually calibrate each wafer, saving working time on the process line. The method of using the extreme value of the optical signal to determine the position of the focus ring is not affected by the material of the focus ring and can be measured on different materials. The optical non-contact measurement method is adopted to avoid the movement of the focus ring caused by directly touching the focus ring during the measurement process.

Description of the drawings

Other features, objects and advantages of the present invention will become more apparent by reading the detailed description of the non-limiting embodiments with reference to the following drawings:

Figure 1 shows a schematic top view of a wafer focus ring gap measurement device according to a specific embodiment of the present invention;

Figure 2 shows a schematic side cross-sectional view of a wafer focusing ring gap measuring device according to a specific embodiment of the present invention;

Figures 3 and 7 show a schematic diagram of the principle of measuring the focus ring by the gap measurement module of a wafer focus ring gap measurement device according to a specific embodiment of the present invention;

Figure 4 shows a schematic diagram of the gap collection module in a wafer focusing ring gap measurement device and each module and circuit in the host computer according to a specific embodiment of the present invention;

Figure 5 shows a schematic diagram of the overall operation flow of a wafer focus ring gap measurement device according to a specific embodiment of the present invention;

Figure 6 shows a schematic flow chart of the measurement operation of a wafer focus ring gap measurement device according to a specific embodiment of the present invention;

Figure 8 shows a schematic diagram of measurement information obtained during the operation of a wafer focus ring gap measurement device according to a specific embodiment of the present invention; and

Figure 9 shows a schematic diagram of a wafer focusing ring gap measuring device according to a specific embodiment of the present invention.

标号说明：Label description:

1. Wafer focus ring gap measurement device;

2. Focus ring;

3. Electrostatic chuck;

4. Measurement module;

41. Light source; 42. Detector; 43. Beam splitter;

44. Optical fiber; 45. Lens; 46. Focus; 47. Drive module;

5. Collection module;

6. Processing module;

7.Transmission module;

8. Power supply module;

11.Host computer;

111. I/O module; 112. Processing module; 113. Power supply module.

Detailed ways

Those skilled in the art understand that in a preferred embodiment, the unique technical features included in the present invention include:

Figure 1 shows a top view of the wafer focus ring gap measuring device 1, the focus ring 2 and the electrostatic chuck 3. Correspondingly, Figure 2 shows the wafer focus ring gap measuring device 1, the focus ring 2 and the electrostatic chuck 3. and side cross-section. As shown in Figures 1 and 2, the wafer focus ring gap measurement device 1 provided by the present invention is placed on the focus ring 2 and the electrostatic chuck 3. During the semiconductor manufacturing process, the wafer to be processed is adsorbed and fixed by the electrostatic chuck 3, and there is a gap between the wafer and the focusing ring 2, such as the gap shown in Figure 2. When the center of the wafer and the center of the focus ring are misaligned, the gaps between the wafer and the focus ring 2 are not evenly distributed in space, resulting in uneven distribution of the applied electric field during plasma etching processes, which easily causes Arc ignition phenomenon damages wafers, focus rings and electrostatic chucks, so the accuracy of wafer positioning is crucial to semiconductor processing.

The present invention integrates a gap measuring device on a wafer to form a wafer focusing ring gap measuring device 1. The wafer focusing ring gap measuring device 1 is preferably consistent with the size of the wafer processed in the semiconductor manufacturing process. At the wafer pre-processing position, on-site detection and collection of wafer position information can be achieved. In a preferred embodiment, in Figure 2, the sheet below the measurement module 4 is the wafer described in the present invention. In another variation, the wafer can also be replaced with an object that has the same appearance as the wafer, and the gap measurement device can be integrated into the object to form an alternative wafer focusing ring gap measurement. Device 1. Preferably, the wafer focusing ring gap measurement device 1 is provided with a gap measurement module 4 and an acquisition module 5, which are respectively responsible for measuring the gap and collecting data.

Figure 3 shows a schematic diagram of the gap measurement module 4 measuring the focus ring 2. The gap measurement module 4 contains a light source component 41, a detector 42, a beam splitter 43, an optical fiber 44, a lens 45 and a driving module 47. The incident light emitted by the light source component 41 is concentrated at the focus 46 through the beam splitter 43, the optical fiber 44, and the lens 45, and is finally illuminated on the focusing ring 2 and then reflected back, and then passes through the lens 45, the optical fiber 44, and the beam splitter 43. On the detector 42, at this time the detector 42 obtains the optical signal value and passes it to the acquisition module 5 for data processing. The schematic diagram can also be described in Figure 9. Since the gap width is an unknown quantity, the focus of the light spot is not necessarily on the focus ring 2. The driving module 47 can drive the measurement module 4 to translate in the wafer radial direction and adjust the position of the focus 46. When it is exactly on the focus ring 2, the reflected light signal obtained has an extreme value, that is, the value of the detector 42 is an extreme value. . Therefore, the position of the focus ring can be determined by the number of movement steps of the drive module and the corresponding detector value, and the width of the gap between the wafer and the focus ring can be deduced from the known step length and initial position of the drive module.

Further, referring to the embodiment shown in FIG. 3 , those skilled in the art understand that during the operation of the gap measurement device 1 , the optical focus of the optical component is between the edge of the wafer and the focus ring. Further, with reference to the embodiment shown in FIG. 6 , those skilled in the art understand that through the operation of the driving module, the focus moves in the direction of the focus ring or in the opposite direction.

The drive module can use a stepper motor or piezoelectric driver to drive the entire measurement module to translate, or just the fiber and lens.

The drive module can also use a galvanometer. At this time, other components do not move, and only the lens moves or deforms to achieve the effect of changing the focus of the lens, and also achieves the effect of translating the drive module.

With further reference to the embodiments shown in FIG. 3 , FIG. 7 , and FIG. 9 , those skilled in the art will understand that different variations can be used to implement the light source component 41 provided by the present invention, so that the light source component emits the incident light. In a variation, the light source component 41 is a simple light source, such as an LED light source, through which the incident light is emitted in the direction of the focusing ring. In another variation, the light source component 41 is composed of a light source and an optical fiber connected to the light source. In such a variation, the incident light is preferentially emitted in the direction of the focusing ring through the end of the optical fiber. , further referring to the embodiments shown in Figures 1, 2, 3, and Figures 6, 7, and 9, the driving module preferably drives the optical fiber to move, thereby changing the position of the focus shown in Figure 3, and thereby Obtain different reflected light signal values. Furthermore, in such a variation, other components other than the optical fiber, such as the gap collection module 5, can be fixed without being moved by the driving module. These changes are within the scope of the present invention. Furthermore, in such a variation, the end of the optical fiber may be disposed in an opening of the transverse cutout on the outer edge of the wafer, so that the end of the optical fiber is within the wafer, and the end of the optical fiber is There are wafers above and below, and the optical fiber can move inward or outward in the opening, that is, the end of the optical fiber moves toward the focusing ring or in the opposite direction. Further, the incident light emitted by the optical fiber is emitted through the opening. In another variation, the light source component 41 is composed 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 finally emits incident light, and the driving module drives the lens 45 changes, for example, the position or shape of the lens 45 changes. Preferably, the lens 45 can be disposed in a lateral opening at the outer edge of the wafer.

Further, with reference to the embodiments shown in Figures 1, 2, 3 and 6, 7 and 9 above, according to different implementation needs, the gap measurement module (4) and the gap acquisition module (5) can It can be arranged on a wafer in different ways, for example, it can be fixed on the upper surface of the wafer, or it can be fixed in a groove opened on the wafer in the way shown in Figure 9 . In another variation, it is attached and fixed on the outside of the wafer. Those skilled in the art understand that in a preferred manner, the above-mentioned fixing method allows the gap measurement module (4) to move, for example, a track is provided below it so that the driving module can drive the gap measurement module (4) to move, etc. , which are all within the protection scope of the present invention.

Furthermore, a light source component 41 is also provided at the position corresponding to the reference number 41 on the left side in FIG. 9 , but it is located on the side of the wafer, so the light source component and the light source components on other sides cannot be seen from this angle.

Figure 4 is a schematic diagram of each module and circuit in the gap collection module 5 and the host computer 11.

The gap acquisition module 5 contains circuits required to collect the output of the measurement module 4 and, if necessary, provide any input signals required to drive the measurement module 4, such as microprocessors, amplifiers, analog-to-digital converters (ADCs), and current sources. , and filters, etc.

The processing module 6 collects and stores the data of the detector 42 and the driving module 47 obtained by the gap measurement module 4 . The processing module 6 may contain calibration coefficients of the measurement module 4 for calibrating the collected gap data. The memory of the processing module 6 can be RAM, DRAM, ROM, SSD, flash, EPROM, EEPROM, etc. The processing module is used to store and process the collected position information. In a preferred embodiment, it includes a microprocessor, a photoelectric control module, an analog-to-digital converter ADC, a memory, etc.

The transmission module 7 sends the gap information in 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 wireless communication modules, such as infrared, Bluetooth, ZigBee, Wi-Fi, etc., or can also communicate directly through inductive induction coils.

The power supply module 8 provides power for 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 or a wireless charging module, which is connected to the power supply module 113 of the host computer 11 . Specifically, the power supply module can supply power to the gap measuring device 4 and the gap collecting device 5, which are all within the protection scope of the present invention. Further, the photoelectric control module sends a command to the light source in the measurement module to send out specific light pulses or modulated light signals, and also controls the activation and closing of the photodetector in the measurement module, selects the receiving mode, and other controls. Optoelectronic control modules are preferably used to control the brightness of the light source, the response of the receiver, etc.

The host computer 11 can be any microprocessor, such as a computer or 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 can directly communicate with the transmission module 7 of the wafer focusing ring gap measuring device 1 through an inductive induction coil. The I/O module 111 may also include a monitor, keyboard or mouse, etc.

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

Components on the gap measurement device 1 such as the gap measurement module 4 and the gap collection module 5 can be placed above the wafer, or embedded in the pre-processed blind groove of the wafer, making it more conducive to meeting the transmission requirements of the semiconductor process. Film height requirements. Further, those skilled in the art understand that when the gap measurement module 4 is buried in the blind trench, if the emission and reception of incident light and reflected light are considered, the measurement module 4 can be connected to the outside of the wafer. The corresponding position is slotted so that the gap measurement module 4 can emit or receive light beams to the outside, which is within the protection scope of the present invention. Further, grooves can be carved on the wafer, and the depth of the groove is adapted to the height of each component of the wafer focusing ring gap measuring device 1 (for example, as shown in Figures 1 and 2), so that The overall height of the wafer focusing ring gap measuring device 1 does not exceed the height of the wafer, which is more in line with the requirements of semiconductor processing technology. Furthermore, in another variation, the gap measurement module 4 and other devices are attached to the outside of the wafer, that is, facing the measured gap and the focus ring, which is also the case here. within the scope of protection of the invention. For example, the light source part 41 of the gap measurement module 4 is attached to the outside of the wafer.

The number of the gap measurement modules 4 is not limited to 4. Higher positioning accuracy can be obtained by increasing the number, and the range can be between 2-8, or it can be more. In another variation, the number of the gap measurement modules 4 may be reduced, for example, two or three measurement modules 4 may be used to implement the gap measurement described in the present invention.

5 to 8 show schematic diagrams of the operation of the gap measuring device 1 provided by the present invention. Specifically, FIG. 5 is a schematic diagram of the overall operation flow of the gap measuring device 1 . Among them, step S101 is entered first, the gap measuring device is started, and the device power is turned on.

Then step S102 is entered, and the robot hand transfers the gap measuring device 1 to the electrostatic chuck.

Then step S103 is entered, where the host computer sends a wireless signal to notify the gap measurement device 1 to start measurement and wait for the test results.

Then step S104 is entered. After the gap measurement device 1 completes the measurement, it wirelessly sends the result to the host computer.

Then step S105 is entered, the test is completed, and the robot takes back the gap measuring device 1 and shuts down the device.

Figure 6 is a schematic diagram of the measurement operation flow of the gap measurement device 1, and the following description is made with reference to Figures 7 and 8.

First, step S201 is entered, the post-test program self-check is started, and the drive module returns to the zero position D ₀ . Preferably, the gap measurement module is driven to move to the initial position D ₀ .

Then step S202 is entered to determine whether the driving module reaches the end point.

If not, enter step S203, the light source component 41 emits a modulated light signal, the detector 42 receives the light signal intensity data and sends it and the driving module step number to the acquisition module 5; the driving module moves forward one step, preferably, the step size for d. Then return to step S202.

If so, enter step S204, the light source component 41 emits a modulated light signal, the detector 42 receives the light signal intensity data and sends it and the driving module step number to the acquisition module 5; the driving module returns to the zero position D ₀ .

Then entering step S205, the gap collection module 5 calculates the driving module forward step number n corresponding to the maximum point of the detector value based on the previously obtained detector data and driving module step size data, and obtains the value Gap of the gap from the known step size d. = D ₀ +nd.

Further, those skilled in the art understand that during the above processing, regarding the measured light intensity value and the number of driving module steps at the next step, these two data are sent to the acquisition module for storage. After entering S205, the light intensity is measured according to the light intensity. The data finds the maximum value and its corresponding driving module step number n, thereby obtaining the gap distance value Gap.

The initial position D ₀ of the gap measurement module 4 in this field preferably refers to the distance between the focus of the incident light and the edge of the wafer. Each time the driver moves the measurement module one step, the step size is d. A total of N steps have been moved, and each step has a light signal, such as light intensity. The number of moving steps n corresponding to the maximum light intensity can be obtained from the light intensity data. Because the maximum light intensity corresponding to the focus of the spot is on the focusing ring, the gap Gap = D ₀ +nd. The curve shown in Figure 8 can be drawn. The abscissa is the number of steps n or the moving distance nd, and the ordinate is the intensity value. The units in Figure 8 can be set as needed, which is within the scope of the present invention.

Further, referring to the embodiment shown in Figure 5 and Figures 6 and 7, in a variation, the calculation process shown in Figure 6 is completed in the host computer, that is, the gap collection module 5 directly transmits the measurement information to the host computer. , instead of the gap acquisition module 5 calculating the step size and extreme value information. In such a variation, the gap collection module 5 may preferably not be provided with a storage module. In the embodiment shown in FIG. 6 , it is preferred that a storage module is provided in the gap collection module 5 for storing multiple measurement information collected at different step sizes. Furthermore, those skilled in the art understand that whether the calculation is performed by the host computer or by the gap collection module 5, or whether it is synchronous calculation or asynchronous calculation, these changes are within the scope of the present invention.

Furthermore, in another variation, the role of the host computer can be changed according to different implementations. For example, the host computer can be the control host in the wafer processing system, or it can be other devices that cooperate with the control host. The auxiliary system, or a host in the measurement system provided by the present invention, for example refers to a computer or industrial computer that receives, displays or processes wireless data between the edge of the wafer and the gap between the focus ring. These changes are within the scope of the present invention.

Further, with reference to the embodiment shown in FIG. 6 , those skilled in the art understand that the initial position D ₀ of the driving module may be at the innermost side of the wafer, that is, the position furthest away from the focus ring, at a further position. At a position close to the center of the wafer, at this time, after the preferred embodiment shown in Figure 6 starts to be executed, the driving module drives the entire gap measuring device 1 to move toward the edge of the wafer. On the contrary, if the initial position D ₀ of the driving module is close to the edge of the wafer, the driving module drives the entire gap measuring device 1 to move toward the center of the wafer. That is, the advancing direction of the driving module is selected according to the initial position. If the initial position is at the edge of the wafer, it will advance toward the center of the wafer; if the initial position is far from the edge, it will advance toward the edge.

Furthermore, with reference to FIG. 1 , FIG. 2 and FIG. 6 , those skilled in the art will understand that the working mode of the driving module is adapted according to the object driven by the driving module. For example, in the preferred embodiment described above, the driving module is used to drive the entire gap measuring device 1 to move, so that the light source on the gap measuring device 1 moves, and the light emitted by the light source moves accordingly, so that the focus of the incident light changes, the intensity signal of the reflected light also changes accordingly. In another preferred embodiment, the driving module does not drive the entire gap measuring device 1 to move, but only drives the light source to move, for example, directly drives the light source to move, or drives the optical fiber connected to the light source to move, so that the emitted light The emission starting point changes, that is, the above-mentioned effect of driving the entire gap measuring device 1 to move is achieved. In another variation, the driving module is a galvanometer structure, that is, the galvanometer structure changes the shape of the lens connected to the light source, thereby changing the focus of the incident light. Changes in these driving modules are within the protection scope of the present invention.

Referring to the above embodiments, those skilled in the art understand that the light source component 41 is any one of LED or laser diode LD; the photodetector 42 is a photodiode PD or a phototransistor or other photoelectric conversion device; The beam splitter 43 is any one of a beam splitting prism, a transflective plate, and an optical fiber beam splitter; the optical fiber 44 is a plastic optical fiber or a quartz optical fiber; the lens 45 is an aspherical lens or an optical fiber lens; and the driving module 47 is any one of a stepper motor, a piezoelectric driver or a galvanometer, or other driving mechanism capable of producing mechanical displacement.

Those skilled in the art understand that the gap between the 12-inch wafer and the focus ring usually ranges from 0 to 3 mm. In a preferred embodiment, this technical solution sets the zero point position of the drive module where the focus 46 coincides with the edge of the wafer. Corresponding position, D ₀ is zero at this time; the advanced end position of the drive module is 3mm. The focal length of the lens is greater than 3mm, ensuring that the measurement module will not exceed the edge of the wafer when driven by the driving module.

Those skilled in the art understand that in the preferred embodiments provided by the present invention, the wafer focus ring gap measurement device and method utilize an optical gap measurement device integrated on the wafer, by moving or changing the position of the optical gap measurement device The optical gap measurement device detects the position of the optical focus, thereby obtaining the optical signal and position information reflected by the focus ring, and then deriving the gap between the wafer and the focus ring.

The gap measurement module is used to measure the gap between the wafer and the focus ring, and includes a light source, a photodetector, a beam splitter, an optical fiber, a lens, and a drive module; the light source can preferably be an LED or a laser diode LD. and other light sources; the photodetector can be a photodetector device such as a photodiode PD or a phototransistor; the beam splitter is used to separate the light emitted by the light source (i.e., incident light) and the light reflected back from the focusing ring, so that the incident light illuminates onto the focusing ring and collect the reflected light onto a photodetector device. The beam splitter can preferably be a beam splitter prism, a transflective plate, an optical fiber beam splitter, or other types of optical beam splitters, which are all within the scope of the present invention. The optical fiber is used to transmit incident light and reflected light. In a preferred embodiment, it can be implemented using light guide devices such as plastic optical fiber and quartz optical fiber. The lens is used to converge incident light and collect reflected light, and can be implemented with aspherical lenses, fiber optic lenses, etc.; the drive module is used to drive the measurement module, which can be implemented with stepper motors, piezoelectric drivers, galvanometers, etc.

The process of measuring the gap is as follows: turn on the power, and the robot moves the measuring device to the electrostatic chuck and within the focusing ring. The microprocessor in the processing module runs the built-in program, starts the wireless communication module, starts the photoelectric control module after receiving the instruction from the host computer to start measurement, and drives the light source in the measurement module to emit a modulated light signal (which can be pulse, frequency modulation or amplitude modulation light). signal), the optical signal is injected into the beam splitter, and preferably reaches the focusing ring to be measured through the optical fiber and lens and then reflects back to the photodetector along the original path. The photodetector will measure the optical signal (i.e. Reflected light) is transmitted back to the processing module in the gap acquisition module for processing and storage, completing an optical signal detection. Then the processing module sends instructions to the driving module in the gap measurement module. The driving module works and moves the position of the gap measurement device or changes the optical focus position of the lens, and then performs another optical signal detection, and so on. The driving module moves the gap measuring device to complete all positions, that is, all positions are measured. Further, the processing module forms a one-to-one correspondence between the measured optical signal and the moving step length, and the extreme value of the optical signal corresponds is the position of the focus ring. The gap width between the wafer and the focus ring can be obtained from the known step size and initial position of the drive module. The acquisition module sends the gap width result to the host computer through the wireless module. After receiving the confirmation, the host computer shuts down and retrieves the measuring device with a manipulator, and the entire measurement process ends.

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. Those skilled in the art can make various variations or modifications within the scope of the claims, which does not affect the essence of the present invention.

Claims

A wafer focus ring gap measuring device (1), which includes a wafer and is used to measure the gap between the edge of the wafer and the focus ring, characterized in that at least the following device is provided on the wafer:

Gap measurement module (4), used to measure the gap distance between the edge of the wafer and the focus ring;

A gap collection module (5), connected to the gap measurement module (4), is used to collect measurement information of the gap measurement module (4) and transmit the measurement information to a host computer.
The gap measurement device (1) according to claim 1, characterized in that 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 collection module (5) as the measurement information.
The gap measurement device (1) according to claim 2, characterized in that during the operation of the gap measurement device (1), the focus position formed by the incident light is between the edge of the wafer and the focus ring. between and move toward the focus ring or in the opposite direction.
The gap measurement device (1) according to any one of claims 1 to 3, characterized in that the gap measurement module (4) at least includes:

The light source part (41) is at least used to emit incident light to the focusing ring (2);

A photodetector (42), which is at least used to receive the reflected light returned from the focusing ring (2);

A driving module (47), which is at least used to provide a driving function so that the focus position formed by the incident light changes.
The gap measuring device (1) according to claim 4, characterized in that the driving module (47) is used to drive the gap measuring module (4) to move in the direction of the focus ring or in the opposite direction.
The gap measuring device (1) according to claim 4, characterized in that the driving module (47) is connected to the light source part (41), so that the light source part (41) moves in the direction of the focusing ring. Or move in the opposite direction.
The gap measuring device (1) according to claim 4, characterized in that the driving module (47) is a galvanometer, which is used to change the lens connected to the light source part (41) and make the The position of the lens from the focusing ring changes or the lens is deformed, thereby changing the focus.
The gap measurement device (1) according to claim 4, characterized in that the gap measurement module (4) further includes at least one beam splitter (43), which is at least used to separate the reflected light and make The reflected light is collected into the photodetector (42).
The gap measurement device (1) according to claim 4, characterized in that the gap collection module (5) at least includes:

a processing module (6) for processing the collected measurement information; and

A transmission module (7), which is connected to the processing module and used to transmit the collected measurement information to the host computer;

Wherein, the processing module (6) at least includes the following modules:

microprocessor;

A photoelectric control module, which is connected to the microprocessor and is used to control at least the light source component (41) and/or the photodetector (42);

An analog-to-digital converter ADC is connected to the photoelectric control module and used to convert the analog signal into a digital signal. The digital signal is transmitted to the host computer through the transmission module (7).
The gap measurement device (1) according to any one of claims 1 to 9, characterized in that the gap measurement module (4) and the gap acquisition module (5) are arranged in any one of the following ways On the wafer:

- fixed on the upper surface of the wafer;

-Be fixed in the groove cut on the wafer; or

- Attached and fixed to the outside of the wafer.
The gap measurement device (1) according to claim 10, characterized in that when the gap measurement module (4) and the gap collection module (5) are fixed in the groove opened on the wafer, , the outer edge of the wafer has an opening, and the opening communicates with the tank body, and the incident light emitted by the light source component (41) is emitted through the opening.
The gap measuring device (1) according to claim 11, characterized in that the light source part (41) retracts the wafer through the outer edge opening of the wafer through the driving module (47). inside, or move in the direction of the focus ring through the driving module (47).
The gap measurement device (1) according to claim 12, characterized in that, except for the light source (41), other components of the gap measurement module (4) are fixed on the upper surface of the wafer or the wafer. Inside the groove cut out on the disc.
A measurement system for measuring the gap between the wafer edge and the focus ring, which at least includes a host computer (11) and the wafer focus ring gap measurement device according to any one of claims 1 to 13 (1) When the measurement system is working, the wafer focus ring gap measurement device (1) is placed and adsorbed on the electrostatic chuck (3) that is compatible with the focus ring (2).
A measurement method based on the wafer focus ring gap measurement device (1) according to any one of claims 1 to 13, which is used to measure the gap between the wafer edge and the focus ring, and includes the following steps :

i. The gap measurement module emits incident light and receives reflected light signals, and sends the reflected light signals and the number of steps moved by the gap measurement module to the gap collection module;

ii. The gap measurement module moves to the next measurement position and repeats step i until the gap measurement module has moved to the end point;

iii. The gap acquisition module calculates the gap distance between the wafer and the focus ring based on the reflected light signal and the step number information.
The measurement method according to claim 15, characterized in that, in the step iii, the gap distance is: the initial position D 0 of the gap measurement module plus the movement step corresponding to the extreme value of the reflected light signal. Number n*step size d, that is, D 0 +nd.