Device for detecting precision of wafer edge finder

Abstract

The utility model discloses a device for detecting the precision of a wafer edge finder. The device comprises a first detection sensor, a second detection sensor, a special wafer for testing and a control module, the first detection sensor is aligned with the edge of the centering wafer in centering precision detection; a test through hole is formed in the special test wafer; the second detection sensor is aligned with the test through hole of the wafer special for testing in the edge searching precision detection; and the control module is used for receiving the edge position information transmitted by the first detection sensor and the position information of the test through hole transmitted by the second detection sensor, and comparing with historical record data to judge centering and edge searching precision. According to the detection device provided by the invention, the centering precision of the edge finder can be monitored in real time under the condition that the current situations of the edge finder and the machine table are not changed, the edge finding precision of the edge finder can be regularly monitored by adopting the wafer special for testing, and whether the precision of the edge finder is reduced or not and the reduction degree can be found in time.

Description

Technical Field

[0001] The utility model belongs to the technical field of semiconductor production, and particularly relates to a device for detecting the accuracy of a wafer edge finder. Background Art

[0002] In the prior art, crystal orientation reference points are provided on all silicon wafers. The crystal orientation reference points are generally flat edges or V-shaped notches (referred to as Notch in the industry) to facilitate the positioning of the wafers. In a wafer manufacturing factory, edge finders are required for the processing or measurement of each station, which plays a key role in positioning the wafers on the machine tool. Especially for a laser engraving machine, if the accuracy of the edge finder is abnormal, it will directly affect the offset of the engraved characters, resulting in abnormal quality.

[0003] An edge finder generally includes a detection component such as a CCD light source detection component and a driving component. The position information of the initial position of the wafer is detected by the CCD light source detection component, and then the wafer is driven to move by the driving component, so that the center and notch of the wafer are adjusted to the set position and set direction in sequence (in this application, the step of positioning the center of the wafer is called the centering step, and the step of positioning the notch direction is called the edge finding step) for subsequent operations.

[0004] In the operation of the wafer edge finder, due to long-term use, the aging of the driving component or the CCD light source detection component of the edge finder causes the decline of the edge finding accuracy, and the center and notch angle of the wafer after positioning deviate. Moreover, it is impossible to detect to what extent the edge finding accuracy has declined and the starting trend of the decline by existing means, which affects the quality of wafer processing. Summary of the Utility Model

[0005] The purpose of the utility model is to provide a device for detecting the accuracy of a wafer edge finder to solve the deficiencies of the prior art.

[0006] The purpose of the utility model is realized by the following technical solutions:

[0007] A device for detecting the accuracy of a wafer edge finder includes a first detection sensor, a second detection sensor, a test-specific wafer, and a control module;

[0008] The first detection sensor is arranged to face the edge of the centering wafer during the centering accuracy detection, and is used to detect the edge position information during the centering process of the centering wafer;

[0009] The test-specific wafer is provided with test through holes;

[0010] The second detection sensor is arranged to face the test through holes of the test-specific wafer during the edge finding accuracy detection, and is used to detect the position information of the test through holes of the test-specific wafer after edge finding;

[0011] The control module is electrically connected to the first detection sensor and the second detection sensor, and is configured to receive the edge position information transmitted by the first detection sensor and the position information of the test through-hole transmitted by the second detection sensor, and determine the centering and edge-finding accuracy by comparing with historical record data.

[0012] Preferably, the device for detecting the accuracy of a wafer edge finder further includes a wafer position detection sensor electrically connected to the control module;

[0013] The wafer position detection sensor is configured to detect whether the centered wafer or the test-specific wafer is placed at the target position, and transmit the detection information to the control module;

[0014] The control module is configured to control the first detection sensor to start and stop collecting data according to the detection information.

[0015] Preferably, the control module is further configured to control the second detection sensor to start and stop collecting data.

[0016] Preferably, the device for detecting the accuracy of a wafer edge finder further includes a fixed column;

[0017] The first detection sensor, the second detection sensor, and the wafer position detection sensor are all fixed on the fixed column;

[0018] During accuracy detection, the fixed column is fixed on one side of the edge finder, and the first detection sensor, the second detection sensor, and the wafer position detection sensor are located at the target position.

[0019] Preferably, the first detection sensor is a through-beam sensor.

[0020] Preferably, the second detection sensor is a fiber optic through-beam sensor.

[0021] Preferably, the test through-hole is a round hole.

[0022] Preferably, the test through-hole is arranged near the edge of the test-specific wafer.

[0023] The detection device provided by the present application can realize real-time monitoring of the centering accuracy of the edge finder without changing the current status of the edge finder and the machine tool. By using the test-specific wafer, regular monitoring of the edge-finding accuracy of the edge finder can be realized, and it can be timely detected whether the accuracy of the edge finder has decreased and the degree of decrease, so that targeted maintenance and remedial measures can be taken to keep the edge finder in a normal working state, improve the utilization rate of wafer manufacturing equipment and product quality. Description of the Drawings

[0024] Figure 1 It is a structural schematic diagram of a device for detecting a wafer edge finder provided by this application;

[0025] Figure 2 It is the wafer center information data line when the centering accuracy does not change during centering accuracy detection;

[0026] Figure 3 It is a comparison diagram of the wafer center coordinates and the center position coordinates of the edge finder when the centering accuracy does not change during centering accuracy detection;

[0027] Figure 4 It is the wafer center information data line when the centering accuracy decreases during centering accuracy detection;

[0028] Figure 5 It is a comparison diagram of the wafer center coordinates and the center position coordinates of the edge finder when the centering accuracy decreases during centering accuracy detection.

[0029] Explanation of reference numerals:

[0030] 1 - First detection sensor; 3 - Wafer position sensor; 4 - Fixed column; 5 - Edge finder main body; 6 - Fixed base plate; 7 - Test - specific wafer; 8 - Top Pin; 9 - Chuck; 10 - Detection component; 11 - Second detection sensor; 12 - Test through - hole. Specific embodiments

[0031] The following further describes this application in conjunction with the drawings and specific embodiments.

[0032] The device for wafer edge finder accuracy detection provided by this application, as Figure 1 shown, includes a first detection sensor 1, a second detection sensor 11, a test - specific wafer 7, and a control module. The control module is electrically connected to the first detection sensor 1 and the second detection sensor 11, and can receive the information collected by them and analyze this information to judge the edge finder accuracy.

[0033] Figure 1Shown on the right is a typical wafer edge finder in the prior art, including an edge finder main body 5, which is fixed on a fixed base plate 6. A driving component is provided inside the edge finder main body 5. The edge finder main body is provided with a top pin 8, a chuck 9 and a detection component 10. The chuck can move up and down and can also rotate. During use, first place the wafer on the chuck 9. The chuck 9 rises in height, and the wafer is separated from the top pin 8, so that the wafer can rotate and move. Then, the chuck drives the wafer to rotate. During the rotation process, the detection component 10 detects information such as the edge position and image of the wafer, and confirms the wafer center and notch position information through analysis. The driving component drives the wafer to move to the target position and direction at the center of the edge finder, completing the centering and edge finding process of the wafer. After centering and edge finding are completed, the chuck descends, and the positioned wafer is adsorbed and supported by the top pin to prevent the wafer from moving.

[0034] As described in the background art, when the edge finder is in use, due to reasons such as the aging of the driving component and the detection component, the problem of decreased centering and edge finding accuracy may occur, resulting in inaccurate wafer positioning and affecting subsequent processing. The detection device provided in this application uses the first detection sensor and the second detection sensor in combination with the control module to detect the centering and edge finding accuracy of the edge finder, so as to be able to timely detect whether the accuracy of the edge finder has decreased and the degree of decrease, and thus perform targeted maintenance on the edge finder to ensure that the edge finder can meet the production requirements. Specifically:

[0035] The first detection sensor 1 is arranged to be aligned with the edge of the centering wafer during the centering accuracy detection. When the centering wafer is placed on the edge finder chuck and starts centering and the detection component 10 detects the wafer position information, the first detection sensor 1 also simultaneously detects the edge position information during the centering process of the centering wafer and transmits the detection information to the control module in real time. After the centering of the edge finder is completed (for some edge finders, centering and edge finding are completed in the same stage, and for some edge finders, centering and edge finding are completed in stages. If the centering and edge finding of the edge finder to be detected for accuracy are completed in the same stage, it is specified here that after centering and edge finding are completed), the first detection sensor stops collecting information. The control module analyzes and confirms the position information of the wafer center after centering and records and saves this position information to form historical record center information data. When subsequent wafers are centered, repeat the above operations to obtain the newly detected wafer center information data, and compare it with the historical record center data to determine whether the accuracy of the edge finder has decreased. When the accuracy of the edge finder remains unchanged, the continuously detected wafer center position information will not change either. As Figure 2 shown, the recorded wafer center information data will maintain a horizontal straight line. After coordinate transformation, calculate the center coordinates of the circle, as Figure 3As shown, after centering, the wafers are all at the center target position of the edge finder. The center coordinates of the circle are 0, 0 relative to the center coordinates of the edge finder, and there is no eccentricity. When the accuracy of the edge finder decreases, the wafer center position information continuously detected will change. For example, Figure 4 as shown, the recorded wafer center information data will no longer be a horizontal straight line, but a trend line that rises or falls. After coordinate transformation, the center coordinates of the circle are calculated. For example, Figure 5 as shown, after centering, the center of the wafer is offset from the center target position of the edge finder. The center coordinates of the wafer are 10, 10 relative to the center coordinates of the edge finder, not 0, 0, showing an eccentricity phenomenon. By observing the degree of deviation of the trend line from the center, the degree of decrease in the centering accuracy of the edge finder can be judged.

[0036] The first detection sensor can adopt the detection sensors used in the edge finder in the prior art, such as opposed sensors (such as CCD opposed sensors, etc.), CCD image sensors, etc. (in this application, a Keyence brand CCD opposed sensor is specifically adopted).

[0037] When the edge finding accuracy decreases, the notch alignment angle will change. For example, after the edge finding is completed, the set angle of the notch is 0°, and the notch angle of the wafer after edge finding is 0.1°. This will cause the position of the reference point in the subsequent processing process to shift, resulting in quality abnormalities. Since there is no detection tool to provide an early warning when there is a slight deviation in notch positioning in the prior art, it is impossible to judge whether the edge finding angle of the edge finder reaches the expected accuracy.

[0038] This application provides a dedicated test wafer 7. A test through hole 12 is provided on the dedicated test wafer. A second detection sensor 11 is used to align with the test through hole of the dedicated test wafer during the edge finding accuracy detection, and the position information of the test through hole of the dedicated test wafer after edge finding is detected. The second detection sensor preferably adopts a fiber optic opposed sensor. Specifically:

[0039] During the edge angle accuracy detection, the test-specific wafer is placed on the edge patrol chuck, and then the detection component and driving component of the edge patrol start to center and find the edge, and the test-specific wafer is adjusted to the target position and direction. After the centering and finding the edge are completed, the test through hole 12 is exactly placed in the detection range of the second detection sensor. The second detection sensor detects the position information of the test through hole and transmits the information to the control module, which records and analyzes it. When the second detection sensor is a fiber optic cross-beam sensor, the test through hole is exactly between the transmitting end and the receiving end. The light beam emitted by the transmitting end can pass through the test through hole and be received by the receiving end. The receiving end transmits the received light intensity data to the control module, and the control module records the received light intensity data to form historical record data. When the edge-finding accuracy remains unchanged, after each centering and edge-finding of the test-dedicated wafer, the position of the test through hole remains unchanged, and the light beam can completely pass through the test through hole each time. Therefore, the recorded light intensity data will remain as a relatively high horizontal straight line. When the edge-finding accuracy begins to decrease, after the centering and edge-finding of the test-dedicated wafer are completed, the position of the test through hole changes, and the relative target position is offset. Therefore, part of the light beam emitted by the transmitting end will be blocked, so the intensity of the light beam received by the receiving end changes. By calculating the degree of change in the light beam intensity, the degree of decrease in edge-finding accuracy can be determined. When the receiving end cannot receive the light beam at all, it proves that the centering or edge-finding accuracy of the edge patrol device has changed significantly, and timely maintenance is required.

[0040] The first detection sensor needs to collect wafer edge information. The sensor is fixed and data collection starts only when the wafer is rotating during centering. This is how the edge information of the entire wafer can be detected. The centering accuracy is evaluated by calculation to meet the requirements and monitor whether the centering accuracy has a variation trend. The second detection sensor does not need to detect the wafer edge position information, so it can be detected after the edge search is completed. From the above content, it can be seen that the edge search accuracy is related to the centering accuracy. When the centering accuracy changes, the test through-hole position will also change, affecting the edge search accuracy. Therefore, it is recommended to perform edge search accuracy detection on the basis of ensuring that the edge patrol device has a high centering accuracy.

[0041] Special wafers for testing can also be used for centering accuracy testing. However, as analyzed above, centering accuracy testing does not require testing the position of the test through-holes, and can be performed during normal wafer edge inspection production. Therefore, the centering accuracy of the edge inspector can be monitored in real time. However, the edge finding accuracy requires the use of special wafers for testing, which can be monitored regularly at regular intervals.

[0042] Since the transmitting end generally emits a circular light beam, the test through hole is preferably a circular hole. The size of the through hole can be adjusted according to actual conditions, preferably 1 mm.

[0043] The position of the test through-hole on the wafer can be adjusted arbitrarily, but it should not obstruct the detection of the first detection sensor. Preferably, the test through-hole is arranged near the edge of the test-specific wafer and far from the center position, and is more sensitive to the change of edge-finding accuracy.

[0044] The wafers dedicated for testing can be made of wafers that meet the requirements of the machine, such as size, flatness, cleanliness, integrity, etc.

[0045] Preferably, the detection device provided by the present application further includes a fixed column 4, which is fixed on one side of the edge finder. The first detection sensor 1 and the second detection sensor 11 are fixed on the fixed column 4. Adjust the installation position of the fixed column and the positions of the first detection sensor and the second detection sensor on the fixed column so that the first detection sensor and the second detection sensor are located at the target positions during accuracy detection. Specifically, the first detection sensor is arranged at the edge of the wafer at the center target position of the edge finder after alignment and centering, and the second detection sensor is arranged at the test through-hole on the test-specific wafer at the center target position and direction of the edge finder after alignment, centering and edge-finding.

[0046] Preferably, the detection device provided by the present application further includes a wafer position detection sensor 3, which is also electrically connected to the control module. The wafer position detection sensor 3 is used to detect whether the centering wafer or the test-specific wafer is placed at the target position and transmit the detection information to the control module; the control module can control the first detection sensor to start and stop collecting data according to the detection information.

[0047] Preferably, the wafer position detection sensor 3 is also arranged on the fixed column 4 and aligned with the target position of the wafer. Specifically, after the wafer is placed on the chuck 9 of the edge finder, the chuck 9 rises in height, and the wafer is separated from the top pin 8, so that the wafer can rotate and move, and centering and edge-finding start. The wafer position detection sensor 3 is arranged to align with the wafer after the chuck rises. After the chuck rises and the wafer position detection sensor 3 detects the wafer, it transmits the detection information to the control module. After receiving the information, the control module controls the first detection sensor to start collecting signals. When the edge finder completes centering and edge-finding, the chuck 9 descends, and the positioned wafer is adsorbed by the top pin 8 to prevent the wafer from shifting. When the chuck descends, the wafer leaves the detection range of the wafer position detection sensor 3, and the wafer position detection sensor no longer detects the wafer. The control module controls the first detection sensor to stop collecting signals, which can save costs and reduce the working time of the first detection sensor.

[0048] The second detection sensor can be manually turned on and off by personnel. Preferably, the control module controls the second detection sensor to start and stop collecting data.

[0049] The control module can adopt a PLC control system, including conventional components such as a memory, a data collector, a processor CPU, a display, etc., and can perform simple data processing and logical analysis functions. Preferably, the control module further includes an alarm, and a certain alarm threshold can be preset. For example, for edge finding accuracy detection, the alarm threshold of the light intensity change when the accuracy drops is set at ±5%. When the newly detected light intensity change value ≤ 5%, it is determined that the edge finding accuracy has not dropped. When the newly detected light intensity change value > 5%, it is determined that the edge finding accuracy has dropped, and an alarm is triggered, such as an audible and visual alarm, to remind the staff to pay attention.

[0050] In summary, the detection device provided by the present application can realize real-time monitoring of the centering accuracy of the edge finder without changing the current situation of the edge finder and the machine tool. By using a dedicated test wafer, regular monitoring of the edge finding accuracy of the edge finder can be realized, and it can timely detect whether the accuracy of the edge finder has dropped and the degree of the drop, so that targeted maintenance and remedial measures can be taken to keep the edge finder in a normal working state, improve the utilization rate of the wafer manufacturing equipment and the product quality.

[0051] Although the preferred embodiments of the present invention have been described, those skilled in the art can make additional changes and modifications once they know the basic creative concept. Therefore, the appended claims are intended to be construed as including the preferred embodiments and all changes and modifications falling within the scope of the present invention. Obviously, those skilled in the art can make various changes and variations to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention also intends to include these modifications and variations.

Claims

1. A device for precision detection of a wafer edge inspector, characterized in that, It includes a first detection sensor, a second detection sensor, a test-specific wafer, and a control module; The first detection sensor is arranged to align with the edge of the centering wafer during centering accuracy detection, and is used to detect the edge position information during the centering process of the centering wafer; Test through-holes are formed in the test-specific wafer; The second detection sensor is arranged to align with the test through-holes of the test-specific wafer during edge-finding accuracy detection, and is used to detect the position information of the test through-holes after edge-finding of the test-specific wafer; The control module is electrically connected to the first detection sensor and the second detection sensor, and is used to receive the edge position information transmitted by the first detection sensor and the position information of the test through-holes transmitted by the second detection sensor, and judge the centering and edge-finding accuracies by comparing with historical record data.

2. The device for precision detection of a wafer edge finder according to claim 1, wherein, It further includes a wafer position detection sensor electrically connected to the control module; The wafer position detection sensor is used to detect whether the centering wafer or the test-specific wafer is placed at the target position, and transmit the detection information to the control module; The control module is used to control the first detection sensor to start and stop collecting data according to the detection information.

3. The device for detecting the accuracy of a wafer edge finder according to claim 2, wherein The control module is further used to control the second detection sensor to start and stop collecting data.

4. The device for precision detection of a wafer edge inspector according to claim 2, characterized in that, It further includes a fixed column; The first detection sensor, the second detection sensor, and the wafer position detection sensor are all fixed on the fixed column; During accuracy detection, the fixed column is fixed on one side of the edge finder, and the first detection sensor, the second detection sensor, and the wafer position detection sensor are located at the target position.

5. The device for detecting the accuracy of a wafer edge finder according to claim 1, wherein The first detection sensor is a transmissive sensor.

6. The device for detecting the accuracy of a wafer edge finder according to claim 1, wherein The second detection sensor is a fiber optic transmissive sensor.

7. The device for detecting the accuracy of a wafer edge finder according to claim 1, wherein The test through-holes are round holes.

8. The device for detecting the accuracy of a wafer edge finder according to claim 1, wherein The test through-holes are arranged close to the edge of the test-specific wafer.

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