Thickness measuring method and device for LED wafer with vertical structure, spot measuring machine and medium

Abstract

The invention discloses a method and device for measuring the thickness of an LED wafer of a vertical structure, a spot measurement machine table and a medium, and relates to the technical field of wafer measurement, and the method comprises the steps: loading a wafer on the spot measurement machine table; image information of the wafer is collected, and mark points of the wafer are identified according to the image; constructing at least two measurement points according to the mark points; respectively measuring height information of the measuring points; calculating thickness range information and total thickness change information of the wafer according to the height information; judging whether the wafer is qualified or not according to the thickness range information and the total thickness change information; if yes, testing performance parameters of each chip in the wafer, and cutting the wafer to form independent chips; and if not, a thickness abnormity alarm signal is generated. According to the invention, the thickness test and the performance test can be carried out through the same point test machine, the transfer frequency of the wafer is reduced, the technological process is reduced, and the production efficiency is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of wafer measurement, and particularly relates to a method, device, probe station and medium for measuring the thickness of a vertical structure LED wafer. Background Art

[0002] In the field of manufacturing vertical structure LED wafers, it is necessary to grind and thin the wafers and then measure the wafer thickness and TTV (Total Thickness Variation) to determine whether the wafers meet the product technical requirements.

[0003] Currently, the methods for measuring the wafer thickness mainly include contact measurement and non-contact measurement. However, no matter which method is adopted, it is necessary to move the wafer to a dedicated measuring machine for measurement and then transfer it to the next machine, which is not only time-consuming and laborious, increasing the cost, but also seriously affecting the production efficiency.

[0004] Meanwhile, after the wafers are ground and thinned, the wafers have become very thin. At this time, measuring the wafers will cause abnormal problems such as scratching, fragmenting and contamination to the wafers, seriously affecting the product quality. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a method, device, probe station and medium for measuring the thickness of a vertical structure LED wafer, which can reduce the number of wafer transfers and improve the production efficiency.

[0006] To solve the above technical problem, the present invention provides a method for measuring the thickness of a vertical structure LED wafer, including: loading the wafer onto a probe station; collecting image information of the wafer and identifying the marking points of the wafer according to the image; constructing at least two measurement points according to the marking points; respectively measuring the height information of the measurement points; calculating the thickness range information and the total thickness change information of the wafer according to the height information; judging whether the wafer is qualified according to the thickness range information and the total thickness change information; when the judgment is yes, testing the performance parameters of each chip in the wafer and performing cutting processing on the wafer to form independent chips; when the judgment is no, generating a thickness abnormal alarm signal.

[0007] As an improvement of the above solution, the measurement points include a center point and at least one edge point, the center point is located at the center position of the wafer, and the edge point is located in the area between the center point and the wafer edge.

[0008] As an improvement of the above solution, the measurement points include a center point and four edge points, the center point is located at the center position of the wafer, and the edge points are arranged in a circular array with the center point as the center in the area between the center point and the wafer edge.

[0009] As an improvement to the above solution, the step of measuring the height information of the measurement point includes: driving the probe of the point measurement machine to gradually move in the direction of the wafer from a preset height position; when the probe touches the measurement point of the wafer and the probe detects that the real-time pressure is the preset pressure, driving the probe to stop moving; generating the height information of the measurement point according to the movement information of the probe.

[0010] As an improvement to the above solution, the step of determining whether the wafer is qualified according to the thickness range information and the total thickness change information includes: comparing the thickness range information with a preset thickness range threshold, and comparing the total thickness change information with a preset total thickness change threshold; when the thickness range information is within the thickness range threshold and the total thickness change information is within the total thickness change threshold, it indicates that the wafer is qualified, otherwise, it indicates that the wafer is unqualified.

[0011] As an improvement to the above solution, the thickness measurement method for the vertical structure LED wafer further includes: sending the height information, thickness information, and total thickness change information to the MES system.

[0012] As an improvement to the above solution, the performance parameters include VF information, WLD information, and IV information.

[0013] Correspondingly, the present invention further provides a computer device, including a memory and a processor, where the memory stores a computer program, and wherein, when the processor executes the computer program, the steps of the above-mentioned thickness measurement method for the vertical structure LED wafer are implemented.

[0014] Correspondingly, the present invention further provides a point measurement machine, which includes a machine body and the above computer device, and the computer device is arranged inside the machine body.

[0015] Correspondingly, the present invention further provides a computer-readable storage medium, on which a computer program is stored, and wherein, when the computer program is executed by a processor, the steps of the above-mentioned thickness measurement method for the vertical structure LED wafer are implemented.

[0016] Implementing the present invention has the following beneficial effects:

[0017] The present invention integrates a thickness measurement method on a point measurement machine, and there is no need to move the wafer to a dedicated measurement machine for measurement. The thickness test and performance test can be carried out through the same point measurement machine, reducing the number of wafer transfers, reducing the process flow, and improving production efficiency;

[0018] Meanwhile, the present invention measures the thickness of the wafer quickly and accurately through a probe station, which can effectively control the wafers with abnormal incoming materials, significantly improve the product quality, reduce the cost, and thus gain an advantage in the fierce market competition;

[0019] In addition, the present invention adopts the probe touch measurement technology to avoid damaging the grains on the wafer surface, ensuring the measurement accuracy and repeatability;

[0020] Furthermore, the present invention can automatically save the measurement data and upload it to the MES system for subsequent analysis and traceability. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a flowchart of the first embodiment of the method for measuring the thickness of a vertical structure LED wafer according to the present invention;

[0022] Figure 2 is a schematic diagram showing the distribution of measurement points in the method for measuring the thickness of a vertical structure LED wafer according to the present invention;

[0023] Figure 3 is a flowchart of the second embodiment of the method for measuring the thickness of a vertical structure LED wafer according to the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0024] To make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings. It is hereby declared that the directional terms such as up, down, left, right, front, back, inside, outside, etc. that appear or will appear in the present invention are only based on the accompanying drawings of the present invention and do not specifically limit the present invention.

[0025] Refer to Figure 1 , Figure 1 shows a flowchart of the first embodiment of the method for measuring the thickness of a vertical structure LED wafer according to the present invention, which includes:

[0026] S101, loading the wafer onto the probe station;

[0027] S102, collecting the image information of the wafer and identifying the marking points of the wafer according to the image;

[0028] After loading and fixing the wafer onto the probe station, the preset marking points, i.e., Mark points, on the wafer can be located by means of photography.

[0029] S103, constructing at least two measurement points according to the marking points;

[0030] Furthermore, the measurement points include a center point and at least one edge point. The center point is located at the center position of the wafer, and the edge point is located in the area between the center point and the edge of the wafer.

[0031] Such as Figure 2As shown, in this embodiment, the measurement points include a center point 1 and four edge points 2. The center point 1 is located at the center of the wafer, and the edge points 2 are arranged in a circular array with the center point 1 as the center in the area between the center point 1 and the edge of the wafer.

[0032] In practical applications, the four edge points 2 can be set at the four positions of the upper, lower, left, and right of the wafer, so as to realize the all-round and multi-angle measurement of the wafer.

[0033] S104, measure the height information of the measurement points respectively;

[0034] Furthermore, the step of measuring the height information of the measurement points includes:

[0035] (1) Drive the probe of the probe station to gradually move towards the wafer from the preset height position;

[0036] In this embodiment, the preset height is 220mm, but it is not limited thereto and can be set according to the actual situation.

[0037] (2) When the probe touches the measurement point of the wafer and the probe detects that the real-time pressure is the preset pressure, drive the probe to stop moving;

[0038] In this embodiment, the preset pressure is 0.5g, but it is not limited thereto and can be set according to the actual situation.

[0039] (3) Generate the height information of the measurement point according to the movement information of the probe.

[0040] For example, the probe slowly touches the measurement point of the wafer at a height of 220mm. When the probe touches the surface of the measurement point and generates a gram weight value of 0.5g, calculate the height information of the measurement point according to the movement information of the probe.

[0041] Therefore, the present invention adopts the probe touch measurement technology to avoid damaging the grains on the surface of the wafer, and at the same time ensures the accuracy and repeatability of the measurement.

[0042] S105, calculate the thickness range information and the total thickness change information of the wafer according to the height information;

[0043] Correspondingly, the thickness information X of each measurement point can be calculated according to the following formula:

[0044] X = Y - y

[0045] Wherein, Y is the preset height and y is the height information.

[0046] Furthermore, the thickness range information of the wafer can be calculated according to the thickness information of each measurement point:

[0047] For example, measurement points A1, A2, A3, A4, and A5 are provided on a wafer. If the thickness information of measurement point A1 is 135 mm, the thickness information of measurement point A2 is 132 mm, the thickness information of measurement point A3 is 136 mm, the thickness information of measurement point A4 is 131 mm, and the thickness information of measurement point A5 is 136 mm, then the thickness range information of the wafer is 131 mm to 136 mm.

[0048] In addition, the total thickness variation information TTV can be calculated according to the following formula:

[0049] TTV = Xmax - Xmin

[0050] Wherein, Xmax is the maximum value of the thickness information among the measurement points, and Xmin is the minimum value of the thickness information among the measurement points.

[0051] For example, measurement points A1, A2, A3, A4, and A5 are provided on a wafer. If the thickness information of measurement point A1 is 135 mm, the thickness information of measurement point A2 is 132 mm, the thickness information of measurement point A3 is 136 mm, the thickness information of measurement point A4 is 131 mm, and the thickness information of measurement point A5 is 136 mm, then the total thickness variation information of the wafer is: 136 - 131 = 5 mm.

[0052] S106, determine whether the wafer is qualified according to the thickness range information and the total thickness variation information;

[0053] Furthermore, the steps of determining whether the wafer is qualified according to the thickness range information and the total thickness variation information include:

[0054] (1) Compare the thickness range information with a preset thickness range threshold, and compare the total thickness variation information with a preset total thickness variation threshold;

[0055] In this embodiment, the thickness range threshold is 125 mm to 136 mm, and the total thickness variation threshold is 5 mm, but it is not limited thereto and can be set according to actual situations.

[0056] (2) When the thickness range information is within the thickness range threshold and the total thickness variation information is within the total thickness variation threshold, it indicates that the wafer is qualified; otherwise, it indicates that the wafer is unqualified.

[0057] For example, on a wafer, measurement points A1, A2, A3, A4, and A5 are provided. If the thickness information of measurement point A1 is 135 mm, the thickness information of measurement point A2 is 132 mm, the thickness information of measurement point A3 is 136 mm, the thickness information of measurement point A4 is 131 mm, and the thickness information of measurement point A5 is 136 mm, then the thickness range information of the wafer is 131 mm to 136 mm, and the total thickness variation information of the wafer is 5 mm. At this time, the thickness range information (131 mm to 136 mm) exceeds the thickness range threshold (125 mm to 136 mm), so the wafer is unqualified.

[0058] S107, when the judgment is yes, test the performance parameters of each chip in the wafer, and perform a cutting process on the wafer to form independent chips;

[0059] If it is determined that the wafer is qualified, continue to drive the probe station to implement the conventional performance to obtain performance parameters; among them, the performance parameters include VF information, WLD information, and IV information, but are not limited thereto, and can be tested according to actual situations.

[0060] Finally, cut the die pattern on the wafer into individual chips.

[0061] S108, when the judgment is no, generate a thickness anomaly alarm signal.

[0062] If it is determined that the wafer is unqualified, generate a thickness anomaly alarm signal to prompt the operator of the thickness anomaly to determine whether to collect and return the abnormal wafer to the original factory.

[0063] As can be seen from the above, the present invention integrates a thickness measurement method on a probe station, does not require the wafer to be moved to a dedicated measuring machine for measurement, can perform both thickness testing and performance testing through the same probe station, reduces the number of wafer transfers, reduces the process flow, improves production efficiency, effectively controls the outflow of wafers with abnormal thickness, and improves product quality.

[0064] See Figure 3 , Figure 3 shows a flowchart of the first embodiment of the thickness measurement method for a vertical structure LED wafer according to the present invention, which includes:

[0065] S201, load the wafer onto the probe station;

[0066] S202, collect the image information of the wafer, and identify the fiducial points of the wafer according to the image;

[0067] S203, construct at least two measurement points according to the fiducial points;

[0068] S204, measure the height information of the measurement points respectively;

[0069] S205. Calculate the thickness range information and total thickness variation information of the wafer based on the height information;

[0070] S206. Determine whether the wafer is qualified based on the thickness range information and total thickness variation information;

[0071] S207. When the determination is yes, test the performance parameters of each chip in the wafer and perform cutting processing on the wafer to form independent chips;

[0072] S208. When the determination is no, generate a thickness anomaly alarm signal.

[0073] S209. Send the height information, thickness information, and total thickness variation information to the MES system.

[0074] Different from Figure 1 the first embodiment shown, in this embodiment, the height information, thickness information, and total thickness variation information can be automatically saved and sent to the MES system, which is convenient for subsequent analysis and traceability.

[0075] Correspondingly, the present invention also discloses a computer device, including a memory and a processor, where the memory stores a computer program. Among them, when the processor executes the computer program, the steps of the above-mentioned thickness measurement method for vertical structure LED wafers are implemented.

[0076] At the same time, the present invention also discloses a computer-readable storage medium, on which a computer program is stored. Among them, when the computer program is executed by a processor, the steps of the above-mentioned thickness measurement method for vertical structure LED wafers are implemented.

[0077] In addition, the present invention also discloses a probing machine, which includes a machine body and the above-mentioned computer device, and the computer device is arranged inside the machine body.

[0078] In summary, the present invention can quickly and accurately measure the thickness of the wafer through the probing machine, effectively control the incoming wafers with anomalies, significantly improve the product quality, reduce costs, and thus gain an advantage in the fierce market competition; at the same time, the present invention adopts the probe touch measurement technology to avoid damaging the surface grains of the wafer, ensuring the accuracy and repeatability of the measurement; in addition, the measurement data is automatically saved and uploaded to the MES system, which is convenient for subsequent analysis and traceability.

[0079] The above is the preferred embodiment of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements are also regarded as the protection scope of the present invention.

Claims

1. A method for measuring the thickness of a vertical structure LED wafer, characterized in that: include: Load the wafer onto the spot measuring machine; Collecting image information of the wafer, and identifying marking points of the wafer according to the image; Construct at least two measurement points according to the marking points; respectively measuring the height information of the measuring points; Calculating the thickness range information and total thickness variation information of the wafer according to the height information; Determine whether the wafer is qualified according to the thickness range information and the total thickness change information; If the result is yes, the performance parameters of each chip in the wafer are tested, and the wafer is cut into independent chips; If the determination is negative, a thickness abnormality alarm signal is generated.

2. The thickness measurement method of a vertical structure LED wafer as claimed in claim 1, characterized in that: The measurement points include a center point and at least one edge point. The center point is located at the center of the wafer, and the edge point is located in a region between the center point and the edge of the wafer.

3. The thickness measurement method of a vertical structure LED wafer as claimed in claim 1, characterized in that: The measuring points include a center point and four edge points. The center point is located at the center of the wafer, and the edge points are arranged in a circular array with the center point as the center in the area between the center point and the edge of the wafer.

4. The method for measuring thickness of a vertical structure LED wafer as claimed in claim 1, wherein: The step of measuring the height information of the measuring point comprises: Driving the probe of the spot measuring machine to gradually move from a preset height position toward the wafer; When the probe touches the measuring point of the wafer and the probe detects that the real-time pressure is a preset pressure, driving the probe to stop moving; The height information of the measuring point is generated according to the movement information of the probe.

5. The method for measuring thickness of a vertical structure LED wafer as claimed in claim 1, wherein: The step of judging whether the wafer is qualified according to the thickness range information and the total thickness change information comprises: Comparing the thickness range information with a preset thickness range threshold, and comparing the total thickness change information with a preset total thickness change threshold; When the thickness range information is within the thickness range threshold and the total thickness variation information is within the total thickness variation threshold, it indicates that the wafer is qualified; otherwise, it indicates that the wafer is unqualified.

6. The method for measuring thickness of a vertical structure LED wafer as claimed in claim 1, wherein: Also includes: The height information, thickness information and total thickness change information are sent to the MES system.

7. The method for measuring thickness of a vertical structure LED wafer as claimed in claim 1, wherein: The performance parameters include VF information, WLD information and IV information.

8. A computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the steps of the thickness measurement method of a vertical structure LED wafer according to any one of claims 1 to 7 are implemented.

9. A point measuring machine, characterized in that: It comprises a machine body and the computer device according to claim 7, wherein the computer device is arranged in the machine body.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the thickness measurement method of a vertical structure LED wafer according to any one of claims 1 to 8 are implemented.

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