Sampling inspection method and sorting method for adhesion of LED chip electrodes

Abstract

The present invention discloses a sampling method and a sorting method for the adhesion of LED chip electrodes, which relates to the field of semiconductor optoelectronic device testing. The sampling method includes: S1: Classifying wafers according to the batches in which the electrodes are formed to obtain multiple classified wafer groups; S2: Sampling and marking each wafer group to extract one or more marked wafers from each wafer group; S3: Testing and sorting the marked wafers; and extracting one or more marked grains from each marked wafer; S4: Testing the adhesion of the electrodes of the marked grains. The present invention realizes the automatic selection and sampling of wafers and grains, greatly improves the sampling efficiency and accuracy; at the same time, it also effectively avoids missed inspections and the outflow of unqualified risk chips.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor optoelectronic device testing, and particularly to a sampling inspection method and a sorting method for the adhesion of LED chip electrodes. Background Art

[0002] After the existing LED wafers are cut and sorted, that is, after the single-grain finished product process is completed, it is necessary to conduct sampling inspection and verification on the adhesion of P / N electrodes to ensure that the electrode adhesion meets the quality requirements and guarantee the quality of product shipment. The current method of sampling is as follows: Manually and randomly select wafers as sampling wafers at the cutting station, and then randomly manually pick grains from the sorted grains of the ozone wafers for testing. This sampling detection method has the following problems: 1. The process is complex and requires manual operation, resulting in low efficiency. 2. The sampling operation will seriously interfere with the normal production line. 3. The sampling accuracy is low, and the probability of missed inspection is very high. Specifically, since multiple wafers are vapor-deposited in each batch, and they do not enter the cutting station in batches, it is easy to cause missed inspection of wafers in different vapor-deposition batches. 4. The test results are difficult to be timely fed back to the sorting station, making it difficult to accurately intercept, and it is easy to miss unqualified grains. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a sampling inspection method for the adhesion of LED chip electrodes of miniLED wafers, which can improve the detection efficiency and detection accuracy.

[0004] Another technical problem to be solved by the present invention is to provide a sorting method for LED chips based on the adhesion test of electrodes, which can improve the sorting efficiency.

[0005] To solve the above problems, the present invention discloses a sampling inspection method for the adhesion of LED chip electrodes, which includes:

[0006] S1: Classify the wafers according to the batches of electrode formation to obtain multiple classified wafer groups;

[0007] S2: Sample and mark each wafer group to draw one or more marked wafers from each wafer group;

[0008] S3: Test and sort the marked wafers; and draw one or more marked grains from each marked wafer;

[0009] S4: Test the adhesion of the electrodes of the marked grains.

[0010] As an improvement of the above technical solution, in step S1, the wafers are classified according to the pot numbers of electrode evaporation.

[0011] As an improvement of the above technical solution, in step S2, among each group of wafer groups, 1 to 3 wafers that flow into the sorting station earliest are extracted as marked wafers.

[0012] As an improvement of the above technical solution, in step S3, 10 to 40 marked grains are sampled on each marked wafer.

[0013] As an improvement of the above technical solution, the marked grains are evenly distributed in the upper, lower, middle, left and right parts of the marked wafer.

[0014] As an improvement of the above technical solution, in step S3, while sorting the marked grains in the marked wafers, other grains are also sorted, and the marked grains are set with separate sorting grades.

[0015] Correspondingly, the present invention also discloses an LED chip sorting method based on electrode adhesion testing, which includes:

[0016] A1: Classify the wafers according to the batches in which the electrodes are formed to obtain multiple classified wafer groups;

[0017] A2: Load the wafers in the same group of wafer groups into the sorting station and sample and mark them to extract one or more marked wafers from each group of wafer groups;

[0018] A3: Test and sort the marked wafers in the wafer group; during the test and sorting, sample and sort the grains on each marked wafer to obtain marked grains;

[0019] A4: Test the electrode adhesion of the marked grains and determine whether the electrode adhesion is within a preset threshold range;

[0020] When the judgment is yes, test and sort the other wafers in the wafer group;

[0021] When the judgment is no, load another group of wafer groups into the sorting station and repeat steps A2 to A4.

[0022] As an improvement of the above technical solution, in step A1, the wafers are classified according to the electrode evaporation pot batches.

[0023] As an improvement of the above technical solution, in step A2, among each group of wafer groups, 1 to 3 wafers that flow into the sorting station earliest are extracted as marked wafers, and 10 to 40 marked grains are sampled on each marked wafer.

[0024] As an improvement of the above technical solution, in step A3, while sorting the marked grains in the marked wafers, other grains are also sorted, and the marked grains are set with separate sorting grades.

[0025] Implementing the present invention has the following beneficial effects:

[0026] 1. The sampling inspection method for the electrode adhesion of the LED chip of the present invention classifies the wafers according to the batches in which the electrodes are formed, then samples each group of wafers obtained by classification to obtain marked wafers; then samples among the marked wafers to obtain marked grains, and finally detects the electrode adhesion of the marked grains. Based on this sampling inspection method, the automatic selection and sampling of wafers and grains are realized, greatly improving the sampling efficiency and accuracy. At the same time, it also effectively avoids missed inspections and the outflow of unqualified risk chips.

[0027] 2. The sorting method for the LED chip based on the electrode adhesion test of the present invention can provide feedback on the sorting operation according to the electrode adhesion test results. When the test is unqualified, the sorting of the wafers in the same batch is abandoned, effectively improving the sorting efficiency and ensuring the qualification rate of the grains after sorting. Description of the Drawings

[0028] Figure 1 is a flow chart of the sampling inspection method for the electrode adhesion of the LED chip in an embodiment of the present invention;

[0029] Figure 2 is a flow chart of the sorting method for the LED chip based on the electrode adhesion test in an embodiment of the present invention;

[0030] Figure 3 is a schematic diagram of the distribution positions of the marked grains on the marked wafer in an embodiment of the present invention;

[0031] Figure 4 is a grading schematic diagram of each grain on the marked wafer in an embodiment of the present invention. Detailed Embodiments

[0032] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below.

[0033] Refer to Figure 1 , the present invention discloses a sampling inspection method for the electrode adhesion of an LED chip, which includes:

[0034] S1: Classify the wafers according to the batches in which the electrodes are formed to obtain multiple classified wafer groups;

[0035] Specifically, in an embodiment of the present invention, the electrodes of the LED chip are formed by the evaporation method. Therefore, the wafers are classified according to the evaporation pot numbers of the electrodes, and the wafers evaporated in the same pot are divided into a wafer group for subsequent steps.

[0036] In another embodiment of the present invention, the electrodes of the LED chip are formed by the MOCVD method; at this time, the wafers can be classified according to the reactor processing batches, that is, the wafers deposited in the same batch by the reactor are divided into a wafer group, and then subsequent steps are carried out.

[0037] Further, after classification, the wafers in the wafer group are marked.

[0038] S2: Sample and mark each wafer group to extract one or more marked wafers from each wafer group;

[0039] Specifically, after the electrodes are formed, the LED chips go through subsequent processes according to the normal production process without manual intervention. When they enter the sorting station, the sampling and marking steps begin.

[0040] Specifically, in one embodiment of the present invention, the wafers in each wafer group are randomly sampled to determine the marked wafers. In another embodiment of the present invention, 1 to 3 wafers that flow into the sorting station earliest are extracted as the marked wafers. By using this sampling method, the verification timeliness can be maximized.

[0041] S3: Test and sort the marked wafers; and extract one or more marked die from each marked wafer;

[0042] Specifically, all die on the marked wafers are tested and sorted, and 10 to 40 die are extracted as the marked die during the sorting process. Specifically, the marked die should be evenly distributed in the upper, lower, middle, left, and right parts of the marked wafer.

[0043] Further, while sorting the marked die in the marked wafers, other die are also sorted, and a separate sorting grade is set to place the marked die. By using this method, automatic sampling can be achieved, and the sampling efficiency can be improved.

[0044] S4: Test the electrode adhesion of the marked die;

[0045] Specifically, the electrode adhesion of the marked die can be tested according to the method of CN201911164370, but it is not limited thereto.

[0046] Based on the above sampling inspection method, first, full - coverage sampling of wafers from different evaporation furnace batches is achieved, which improves the abnormal detection rate and ensures no missed inspection. Second, while the product is in automatic flow operation, the system automatically selects the sampling wafers and samples the die; this greatly improves the efficiency and accuracy, with high efficiency and strong precision. Third, when sampling the die, by setting the sampling coordinates of the marked die, the sampling positions and sampling numbers of each marked wafer can be made consistent, thus ensuring the accuracy of sampling verification.

[0047] Correspondingly, referring to Figure 2 , the present invention also discloses an LED chip sorting method based on electrode adhesion testing, which includes:

[0048] A1: Classify the wafers according to the batches in which the electrodes are formed to obtain multiple classified wafer groups;

[0049] Specifically, in an embodiment of the present invention, the electrodes of the LED chips are formed by the evaporation method. Therefore, the wafers are classified according to the evaporation pot numbers of the electrodes, and the wafers evaporated in the same pot are divided into one wafer group for subsequent steps.

[0050] In another embodiment of the present invention, the electrodes of the LED chips are formed by the MOCVD method; at this time, the wafers can be classified according to the reactor processing batches, that is, the wafers deposited in the same batch of the reactor are divided into one wafer group, and then subsequent steps are carried out.

[0051] Further, after the classification is completed, the wafers in the wafer group are marked.

[0052] A2: Load the wafers in the same wafer group to the sorting station and sample and mark them to draw one or more marked wafers from each wafer group;

[0053] Specifically, after the electrodes are formed, the LED chips go through subsequent processes according to the normal production process without manual intervention. When they enter the sorting station, the sampling and marking steps begin.

[0054] Specifically, in an embodiment of the present invention, the wafers in each wafer group are randomly sampled to determine the marked wafers. In another embodiment of the present invention, 1 to 3 wafers that flow into the sorting station earliest are drawn as the marked wafers. By using this sampling method, the verification timeliness can be maximized.

[0055] A3: Test and sort the marked wafers in the wafer group; during the test and sorting, sample and sort the grains on each marked wafer to obtain marked grains;

[0056] Specifically, all the grains on the marked wafers are tested and sorted. During the sorting process, 10 to 40 grains are drawn as the marked grains. Specifically, the marked grains should be evenly distributed in the upper, lower, middle, left, and right parts of the marked wafer.

[0057] Further, while sorting the marked grains in the marked wafers, other grains are also sorted, and a separate sorting grade is set to place the marked grains. By using this method, automatic sampling can be realized and the sampling efficiency can be improved.

[0058] A4: Test the electrode adhesion of the marked grains and determine whether the electrode adhesion is within a preset threshold range;

[0059] Specifically, the electrode adhesion of the marked grains can be tested according to the method of CN201911164370, but not limited thereto. After the determination is completed, if the judgment is yes, other wafers in the wafer group are used for test sorting; if the judgment is no, another wafer group is loaded onto the sorting station, and steps A2 to A4 are repeated.

[0060] Based on the above LED chip sorting method for electrode adhesion testing, the sorting operation can be feedback according to the test results of electrode adhesion. When the test is unqualified, the sorting of wafers in the same batch is abandoned, which effectively improves the sorting efficiency and ensures the qualification rate of the sorted grains at the same time.

[0061] The present invention will be further described below with specific embodiments.

[0062] Embodiment

[0063] This embodiment provides a sampling inspection method for the electrode adhesion of LED chips, which is specifically as follows:

[0064] 1. Electrode evaporation is carried out. 99 wafers are loaded in each evaporation furnace, and the wafers in each furnace are divided into a wafer group and marked.

[0065] 2. After the wafers in the wafer group flow to the sorting station, the first two wafers are extracted and marked as marked wafers; specifically, the wafers A087 and A011 that flow to the sorting station earliest are used as marked wafers.

[0066] 3. The marked wafers are tested and sorted; and the grains at fixed coordinates are extracted as marked grains.

[0067] Specifically, refer to Figure 3 , 30 grains at fixed coordinates are extracted. Their positions cover the upper, middle, lower, left, and right positions of the wafer.

[0068] Furthermore, as Figure 4 shown, the marked grains are set to a special grade 149; while sorting other grains (grades 1 - 148), the marked grains of grade 149 are also sorted synchronously.

[0069] 4. The electrode adhesion of the marked grains is tested (CN201911164370).

[0070] The above is the preferred implementation manner of the 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 sampling inspection method for the electrode adhesion of LED chips, characterized in that, it includes: S1: Classify the wafers according to the electrode evaporation pot number to obtain multiple classified wafer groups; among them, the wafers evaporated in the same pot are divided into one wafer group; S2: Sample and mark each wafer group to extract one or more marked wafers from each wafer group; S3: Test and sort the marked wafers; and extract one or more marked grains from each marked wafer; among them, when sampling the grains, set the sampling coordinates of the marked grains so that the sampling positions and the number of samples of the marked grains in each marked wafer are the same; S4: Test the electrode adhesion of the marked grains and determine whether the electrode adhesion is within a preset threshold range.

2. The sampling inspection method for the electrode adhesion of LED chips according to claim 1, characterized in that, in step S2, in each wafer group, 1 to 3 wafers that flow into the sorting station earliest are extracted as the marked wafers.

3. The sampling inspection method for the electrode adhesion of LED chips according to claim 1, characterized in that, in step S3, 10 to 40 marked grains are sampled from each marked wafer.

4. The sampling inspection method for the electrode adhesion of LED chips according to claim 3, characterized in that, the marked grains are evenly distributed in the upper, lower, middle, left and right parts of the marked wafer.

5. The sampling inspection method for the electrode adhesion of LED chips according to claim 1, characterized in that, in step S3, when sorting the marked grains in the marked wafers, other grains are also sorted, and the marked grains are separately set with sorting grades.

6. An LED chip sorting method based on the test of electrode adhesion, characterized in that, it includes: A1: Classify the wafers according to the electrode evaporation pot number to obtain multiple classified wafer groups; among them, the wafers evaporated in the same pot are divided into one wafer group; A2: Load the wafers in the same group into the sorting station and sample and mark them to extract one or more marked wafers from each wafer group; A3: Test and sort the marked wafers in the wafer group; when testing and sorting, sample and sort the grains on each marked wafer to obtain marked grains; among them, when sampling the grains, set the sampling coordinates of the marked grains so that the sampling positions and the number of samples of the marked grains in each marked wafer are the same; A4: Test the electrode adhesion of the marked grains and determine whether the electrode adhesion is within a preset threshold range; if the judgment is yes, test and sort the other wafers in the wafer group; if the judgment is no, load another wafer group into the sorting station and repeat steps A2 to A4.

7. The LED chip sorting method based on the test of electrode adhesion according to claim 6, characterized in that, in step A2, in each wafer group, 1 to 3 wafers that flow into the sorting station earliest are extracted as the marked wafers, and 10 to 40 marked grains are sampled from each marked wafer.

8. The LED chip sorting method based on the test of electrode adhesion according to claim 6, characterized in that, In step A3, while sorting the marked grains in the sorted marked wafer, other grains are also sorted, and the sorted grade of the marked grains is set separately.

Images