Wafer notch identification method, medium and system

Abstract

This invention discloses a wafer notch identification method, medium, and system. The method includes the following steps: S1. Real-time acquisition of photosensitive data during wafer rotation; S2. Sequential acquisition of photosensitive data within each segment to obtain a partitioned photosensitive data dataset organized by segment index i; S3. Calculation of the maximum difference E of the photosensitive values ​​within the i-th segment. i And the encoded value P corresponding to the maximum light sensitivity value within this section. i The encoded values ​​P corresponding to the maximum and minimum light sensitivity values i min; S4. Select the value with the largest difference as the final maximum difference in light sensitivity value E. end At the same time, E was obtained end The corresponding encoded value P end S5. The maximum difference in the final light sensitivity value E end With the preset judgment threshold E λ Compare, if E end >E λ If the Notch port is successfully identified, then the invention is considered to have been successfully identified. This invention offers advantages such as accurate identification.

Description

Technical Field

[0001] This invention mainly relates to the field of ion implantation technology, specifically to a wafer notch identification method, medium, and system. Background Technology

[0002] The basic principle of ion implantation is: an ion beam with an energy on the order of 100 keV is incident into the wafer. The ion beam will undergo a series of physical and chemical interactions with the atoms or molecules in the wafer. The incident ions gradually lose energy and eventually remain in the wafer, causing changes in the composition, structure and properties of the wafer surface, thereby optimizing the wafer surface properties or obtaining some new superior properties.

[0003] Different processes have varying requirements for the direction and location of ion implantation onto the wafer. Therefore, accurate identification of the wafer notch is crucial to ensuring proper wafer orientation during ion implantation. The notch on the wafer is primarily used to mark its location and orientation. In the field of ion implantation, silicon carbide wafers, being processed with more complex techniques, have even higher requirements for wafer orientation and direction. Therefore, accurate identification of the wafer's notch is essential. Incorrect notch identification will lead to wafer ion implantation failure, resulting in product scrap and significant economic losses.

[0004] Existing wafer notch detection methods primarily rely on sensors to monitor the wafer's edge. First, an orientation device rotates the wafer. During this rotation, when the wafer notch approaches the sensor's sensing range, the sensor is triggered, thus detecting the wafer notch.

[0005] Existing wafer notch detection methods primarily rely on the functionality and performance of the sensor. These methods are not suitable for silicon carbide wafers, mainly for the following reasons: 1. Due to the material properties, silicon carbide wafers are mostly transparent, making it difficult for sensors to capture changes in light at the notch port.

[0006] 2. The sensor needs to have the function of detecting the increase in light sensitivity. Currently, sensors that can detect silicon carbide wafers do not have this function. 3. Silicon carbide wafers are prone to slippage during rotation, which reduces the rotational speed. When the sensor detects the Notch port, the increment of the light sensitivity value will decrease, making it difficult to use the increment for detection.

[0007] 4. When capturing the Notch port by detecting the increment of light sensor value using software, the positional deviation is large and the repeatability is low.

[0008] The basic principle of detecting wafer notch ports is to place the wafer on an orientation device and rotate it. Since the sensor is positioned at the edge of the wafer, when the wafer notch port enters the sensor's detection range, the light received by the sensor will change. At this time, the position of the wafer notch port can be determined based on the collected light value.

[0009] Because in actual working conditions, the wafer and positioning device may not be perfectly aligned, the light value received by the sensor during wafer rotation is roughly a sinusoidal waveform with uncertain amplitude. The light value detected at the wafer notch will change, but at this moment, the light value may be less than the amplitude of the sinusoidal waveform. Using a certain light value as a threshold for notch detection will lead to positional errors. Since the presence of the wafer notch causes a sudden increase in the light value increment, this method is not suitable for silicon carbide wafers, even though ordinary wafers can use the change in light value increment as a basis for judgment. Using sensors to collect light values ​​from silicon carbide wafers results in significant noise, leading to large errors in using the light value increment as a basis for judgment, thus causing inaccurate notch positioning. Summary of the Invention

[0010] To address the technical problems existing in the prior art, the present invention provides a wafer Notch identification method, medium, and system with high identification accuracy.

[0011] To solve the above-mentioned technical problems, the technical solution proposed by this invention is as follows: A wafer notch identification method includes the following steps: S1. During the wafer rotation process, real-time light-sensing data is collected to obtain a light-sensing data stream that changes with time or rotation angle; S2. The light-sensing data stream collected during the 360° rotation of the wafer is pre-divided into N consecutive segments. The light-sensing data in each segment is collected sequentially to obtain a segmented light-sensing data set organized according to the segment index i, where i=1,2,3,…,N, and N is a preset positive integer; S3. For the light sensitivity data set of the i-th segment, calculate the maximum difference E of the light sensitivity values ​​within that segment. i And the encoded value P corresponding to the maximum light sensitivity value within this section. i The encoded values ​​P corresponding to the maximum and minimum light sensitivity values i min; where the encoded value is used to characterize the position during wafer rotation; S4. Calculate the differences E1, E2, E3, ..., E1 from all N segments output in step S3. N The values ​​of the coded pairs and their associated values ​​are compared and analyzed, and the largest difference is selected as the final maximum difference E in the light perception value. end At the same time, E was obtained endThe corresponding encoded value P end ; S5. The maximum difference in the final light sensitivity value E end With the preset judgment threshold E λ Compare, if E end >E λ If the Notch port is successfully recognized, then the final encoded value P is determined to be... end The corresponding position is the Notch port position of the wafer.

[0012] Preferably, step S3 specifically includes the following sub-steps: S31. Before starting data collection for segment i, first assign the initial light sensitivity value collected by the sensor to the maximum light sensitivity value variable S for segment i. i The maximum and minimum light sensitivity values ​​S i min; at the same time, assign the current encoded value to the corresponding encoded value record variable; S32. After the data collection for segment i begins, the current light sensitivity value is compared with S... i max and S i Compare with min; if the current light sensitivity value is greater than S... i If the current light sensitivity value is maxed out, then the current light sensitivity value will be assigned to S. i max, and simultaneously record the current encoded value P. i max; if the current light sensitivity value is less than S i min, then assign the light sensitivity value to S. i min, and simultaneously record the current encoded value P. i min; S33. Continue the comparison and update operation until the data acquisition for segment i is completed, then obtain the maximum light sensitivity value S for that segment. i max and minimum light sensitivity S i min, then calculate the maximum difference in light perception E in segment i. i =S i max-S i min.

[0013] Preferably, step S4 specifically includes the following sub-steps: S41: The differences E1, E2, E3…E across all segments N By comparing, we can obtain the largest E. i Value and corresponding P i max value and P i min value; S42: The largest E i Value assigned to E end This serves as the maximum difference in the final light perception value.

[0014] Preferably, the wafer is a conventional wafer or a silicon carbide wafer.

[0015] Preferably, light-sensing data is acquired in real time using a transmissive photoelectric sensor or a reflective photoelectric sensor.

[0016] The present invention also discloses a computer program product, comprising a computer program that, when executed by a processor, performs the steps of the method described above.

[0017] The present invention further discloses a computer-readable storage medium having a computer program stored thereon, the computer program executing the steps of the method described above when run by a processor.

[0018] The present invention also discloses a wafer notch identification system, including a memory and a processor interconnected thereon, wherein the memory stores a computer program, and the computer program executes the steps of the method described above when run by the processor.

[0019] Compared with the prior art, the advantages of the present invention are as follows: The method provided by this invention can not only accurately identify notch ports but also ensure the real-time performance of calculation results, thereby improving production efficiency. This invention is applicable not only to notch port identification of opaque ordinary wafers but also to notch port identification of highly transparent silicon carbide wafers. This invention identifies silicon carbide wafer notch ports by analyzing and processing the light-sensing values ​​collected by the sensor through algorithm optimization, without requiring the sensor to have hardware triggering functionality. The algorithm of this invention is simple, easy to implement, meets the real-time requirements of the system, and improves the production efficiency of ion implantation for silicon carbide wafers. This invention effectively improves the positioning accuracy of silicon carbide wafer notch ports and has high repeatability.

[0020] This invention can accurately capture the notch of a silicon carbide wafer and ensure positioning accuracy even when the wafer and positioning device are not perfectly aligned. This invention does not require the sensor to detect changes in light sensitivity; instead, it uses an algorithm to analyze and process the light sensitivity values ​​collected by the sensor to accurately identify the notch of the silicon carbide wafer. This invention is unaffected by the wafer rotation speed; different numbers of segments can be set for different rotation speeds, making it widely adaptable. This invention provides high positional accuracy and repeatability for capturing the silicon carbide wafer, effectively ensuring product quality and production efficiency. Attached Figure Description

[0021] Figure 1 This is a flowchart of the wafer Notch port identification method according to an embodiment of the present invention.

[0022] Figure 2This is a flowchart illustrating the calculation of the maximum difference in photosensitive values ​​and the corresponding encoded values ​​for segment i in an embodiment of the present invention.

[0023] Figure 3 In this embodiment of the invention, the maximum difference E is obtained by calculating and analyzing all segments. end and the corresponding encoded value P end The flowchart. Detailed Implementation

[0024] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0025] like Figure 1 As shown, the wafer notch identification method provided in this embodiment of the invention includes the following steps: S1. First, the orientation device drives the silicon carbide wafer to rotate, and the sensor collects the light-sensing data in real time. The sensor is either a transmissive photoelectric sensor or a reflective photoelectric sensor.

[0026] Specifically, a silicon carbide wafer is placed on an alignment device, which then rotates the wafer around its center. During this rotation, sensors positioned at the wafer's edge continuously collect real-time light-sensing data. Because the sensors are located at the wafer's edge, the light-sensing value received by the sensors changes when the wafer's notch enters the sensor's detection range. The position of the wafer's notch can then be determined based on this collected light-sensing data. It should be noted that in actual operation, the wafer and the alignment device may not be perfectly aligned. In this case, the light-sensing value received by the sensors during wafer rotation will roughly exhibit a sinusoidal waveform with an uncertain amplitude.

[0027] S2. The data collected during the 360° rotation of the wafer is pre-divided into N segments, and data from each segment is collected sequentially. Here, N is a preset positive integer representing the total number of segments to be divided into for the complete rotation cycle. For different wafer rotation rates, only different numbers of segments N need to be set, providing broad applicability. Segment numbers i are set, i = 1, 2, 3, ..., N, and data is collected and processed sequentially for each segment in ascending order of i.

[0028] S3. When collecting data for the i-th segment, calculate the maximum difference in light sensitivity value E for that segment. i and corresponding encoded value P i max and P i min.

[0029] Specifically, Figure 2 The process for calculating the maximum difference in photosensitive values ​​and the corresponding encoded values ​​for segment i is as follows: Step S3 specifically includes the following sub-steps: S31. Before starting data collection for segment i, first assign the initial light sensitivity value collected by the sensor to the maximum light sensitivity value variable S for segment i. i The maximum and minimum light sensitivity values ​​S i min; at the same time, assign the current encoded value to the corresponding encoded value record variable; S32. After the data collection for segment i begins, the current light sensitivity value is compared with S... i max and S i Compare with min; if the current light sensitivity value is greater than S... i If the current light sensitivity value is maxed out, then the current light sensitivity value will be assigned to S. i max, and simultaneously record the current encoded value P. i max; if the current light sensitivity value is less than S i min, then assign the light sensitivity value to S. i min, and simultaneously record the current encoded value P. i min; S33. Continue performing the above comparison and update operations until the data for segment i is collected, then obtain the maximum light sensitivity value S for that segment. i max and minimum light sensitivity S i min, then calculate the maximum difference in light perception E in segment i. i =S i max-S i min. This difference reflects the fluctuation range of the light sensitivity value within this segment.

[0030] S4. After collecting and calculating data from N segments, calculate and analyze the differences obtained from all segments to obtain the maximum difference E. end and the corresponding encoded value P end .

[0031] Specifically, such as Figure 3 As shown, Figure 3 The final maximum difference in light perception, E, was obtained by calculating and analyzing all segments. end and corresponding encoded value P end Step S4 includes the following sub-steps: S41. The differences E1, E2, E3…E between multiple segments N By comparing, we can obtain the largest E. i Value and corresponding P i max value and P i min value; S42. The largest E i Value assigned to E end This serves as the maximum difference in the final light-sensing value. Simultaneously, based on the direction of change in the light-sensing value when the wafer notch passes through the sensor's detection range under actual operating conditions, P is selected... imin value or P i The max value is assigned to P. end Specifically, if the wafer notch port passes through the sensor's detection range, the increased light transmittance at the notch port leads to a higher light sensitivity value received by the sensor, then P... i The max value is assigned to P. end If the wafer notch port passes through the sensor's detection range, the light transmission or scattering at the notch port will reduce the light sensitivity value received by the sensor (for example, in this example, the light sensitivity value decreases when the wafer notch port passes through the sensor's detection range), then P will be... i The min value is assigned to P. end P end This is the encoding value corresponding to the Notch port position of the silicon carbide wafer obtained in the final determination.

[0032] S5. The maximum difference E end With the set threshold E λ Compare, if E end >E λ If the calculation of the Notch port is successful, then the encoded value P is determined to be... end This indicates the location of the Notch port on the silicon carbide wafer; otherwise, Notch port recognition is considered failed. S6. After identifying the Notch port, finally use the orientation device to rotate the silicon carbide wafer to the specified angle.

[0033] The method provided by this invention can not only accurately identify notch ports but also ensure the real-time performance of calculation results, thereby improving production efficiency. This invention is applicable not only to notch port identification of opaque ordinary wafers but also to notch port identification of highly transparent silicon carbide wafers. This invention identifies silicon carbide wafer notch ports by analyzing and processing the light-sensing values ​​collected by the sensor through algorithm optimization, without requiring the sensor to have hardware triggering functionality. The algorithm of this invention is simple, easy to implement, meets the real-time requirements of the system, and improves the production efficiency of ion implantation for silicon carbide wafers. This invention effectively improves the positioning accuracy of silicon carbide wafer notch ports and has high repeatability.

[0034] This invention can accurately capture the notch of a silicon carbide wafer and ensure positioning accuracy even when the wafer and positioning device are not perfectly aligned. This invention does not require the sensor to detect changes in light sensitivity; instead, it uses an algorithm to analyze and process the light sensitivity values ​​collected by the sensor to accurately identify the notch of the silicon carbide wafer. This invention is unaffected by the wafer rotation speed; different numbers of segments can be set for different rotation speeds, making it widely adaptable. This invention provides high positional accuracy and repeatability for capturing the silicon carbide wafer, effectively ensuring product quality and production efficiency.

[0035] The present invention also discloses a computer program product, comprising a computer program that, when executed by a processor, performs the steps of the method described above.

[0036] The present invention further discloses a computer-readable storage medium having a computer program stored thereon, the computer program executing the steps of the method described above when run by a processor.

[0037] The present invention also discloses a wafer notch identification system, including a memory and a processor interconnected thereon, wherein the memory stores a computer program, and the computer program executes the steps of the method described above when run by the processor.

[0038] The products, media, and systems of the present invention, corresponding to the methods described above, also possess the advantages described above.

[0039] The present invention can implement all or part of the processes in the methods of the above embodiments, or it can be implemented by hardware related to computer program instructions. The computer program can be stored in a computer-readable storage medium. When the computer program is executed by a processor, it can implement the steps of the above method embodiments. The computer program includes computer program code, which can be in the form of source code, object code, executable file, or some intermediate form. The computer-readable storage medium includes: any entity or device capable of carrying computer program code, recording media, USB flash drive, portable hard drive, magnetic disk, optical disk, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signals, telecommunication signals, and software distribution media, etc. The memory is used to store computer programs and / or modules. The processor implements various functions by running or executing the computer programs and / or modules stored in the memory, and by calling data stored in the memory. The memory may include high-speed random access memory, as well as non-volatile memory, such as hard disks, RAM, plug-in hard disks, smart media cards (SMC), secure digital (SD) cards, flash cards, at least one disk storage device, flash memory device, or other volatile solid-state storage devices.

[0040] Explanation of relevant terms: Wafer: A wafer is a silicon wafer used to fabricate silicon semiconductor circuits. Its raw material is silicon. High-purity polycrystalline silicon is dissolved, doped with silicon crystal seeds, and then slowly pulled out to form a cylindrical single-crystal silicon wafer. After grinding, polishing, and slicing, the silicon ingot is formed into a silicon wafer. Domestic wafer production lines mainly produce 8-inch and 12-inch wafers.

[0041] Silicon carbide wafers: Silicon carbide wafers are single-crystal wafers made of silicon carbide (SiC) material. As the core substrate of third-generation semiconductor materials, they are used to manufacture high-temperature, high-power, and high-frequency electronic devices. Essentially, they are circular thin films formed through crystal growth, cutting, and polishing processes, and are the basic carrier for the production of silicon carbide devices.

[0042] Notch: A wafer notch is a physical notch used to identify the orientation of the wafer. It is typically V-shaped or U-shaped and located at the bottom edge of the silicon wafer. Its precise location and ease of machine reading are key features. This characteristic is common in 8, 12, and 18-inch wafers, replacing the flat edges used on earlier, smaller wafers. The above are merely preferred embodiments of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should be considered within the scope of protection of the present invention.

Claims

1. A method for identifying wafer notch ports, characterized in that, Includes the following steps: S1. During the wafer rotation process, real-time light-sensing data is collected to obtain a light-sensing data stream that changes with time or rotation angle; S2. The light-sensing data stream collected during the 360° rotation of the wafer is pre-divided into N consecutive segments. The light-sensing data in each segment is collected sequentially to obtain a segmented light-sensing data set organized according to the segment index i, where i=1,2,3,…,N, and N is a preset positive integer; S3. For the light sensitivity data set of the i-th segment, calculate the maximum difference E of the light sensitivity values ​​within that segment. i And the encoded value P corresponding to the maximum light sensitivity value within this section. i The encoded values ​​P corresponding to the maximum and minimum light sensitivity values i min; where the encoded value is used to characterize the position during wafer rotation; S4. Calculate the differences E1, E2, E3, ..., E1 from all N segments output in step S3. N The values ​​of the coded pairs and their associated values ​​are compared and analyzed, and the largest difference is selected as the final maximum difference E in the light perception value. end At the same time, E was obtained end The corresponding encoded value P end ; S5. The maximum difference in the final light sensitivity value E end With the preset judgment threshold E λ Compare, if E end >E λ If the Notch port is successfully recognized, then the final encoded value P is determined to be... end The corresponding position is the Notch port position of the wafer.

2. The wafer notch identification method according to claim 1, characterized in that, Step S3 specifically includes the following sub-steps: S31. Before starting data collection for segment i, first assign the initial light sensitivity value collected by the sensor to the maximum light sensitivity value variable S for segment i. i The maximum and minimum light sensitivity values ​​S i min; at the same time, assign the current encoded value to the corresponding encoded value record variable; S32. After the data collection for segment i begins, the current light sensitivity value is compared with S... i max and S i Compare with min; if the current light sensitivity value is greater than S... i If the current light sensitivity value is maxed out, then the current light sensitivity value will be assigned to S. i max, and simultaneously record the current encoded value P. i max; if the current light sensitivity value is less than S i min, then assign the light sensitivity value to S. i min, and simultaneously record the current encoded value P. i min; S33. Continue the comparison and update operation until the data acquisition for segment i is completed, then obtain the maximum light sensitivity value S for that segment. i max and minimum light sensitivity S i min, then calculate the maximum difference in light perception E in segment i. i =S i max-S i min.

3. The wafer notch identification method according to claim 1, characterized in that, Step S4 specifically includes the following sub-steps: S41: The differences E1, E2, E3…E across all segments N By comparing, we can obtain the largest E. i Value and corresponding P i max value and P i min value; S42: The largest E i Value assigned to E end This serves as the maximum difference in the final light perception value.

4. The wafer notch identification method according to claim 1, 2, or 3, characterized in that, The wafer can be a conventional wafer or a silicon carbide wafer.

5. The wafer notch identification method according to claim 1, 2, or 3, characterized in that, Light sensitivity data is collected in real time using either a transmissive photoelectric sensor or a reflective photoelectric sensor.

6. A computer program product, comprising a computer program, characterized in that, The computer program is executed by the processor to perform the steps of the method as described in any one of claims 1-5.

7. A computer-readable storage medium having a computer program stored thereon, characterized in that, The computer program, when run by a processor, performs the steps of the method as described in any one of claims 1-5.

8. A wafer notch identification system, comprising an interconnected memory and a processor, wherein the memory stores a computer program, characterized in that, The computer program, when run by a processor, performs the steps of the method as described in any one of claims 1-5.

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