Crystal grain color difference abnormity screening method and system, and computer readable storage medium

Abstract

The invention relates to a crystal grain color difference abnormity screening method and system and a computer readable storage medium. The method comprises the following steps: providing a wafer to be tested; performing image scanning on all the to-be-tested crystal grains on the to-be-tested wafer; performing similarity comparison on the obtained image data of each to-be-detected crystal grain and preset image data; marking the image data of which the similarity is greater than a preset threshold value as crystal grains with normal appearances; wherein the area where the crystal grains with the normal appearance are located is marked as an area to be screened; and marking the crystal grains in a preset number of turns at the edge of the to-be-screened area as the crystal grains with abnormal color difference. By applying the method, the crystal grains with abnormal chromatic aberration can be quickly and accurately screened out.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and in particular to a method and system for screening abnormal grain color difference, and a computer-readable storage medium. Background Art

[0002] In the traditional LED manufacturing process, it is usually necessary to coat the non-light-emitting side with a reflective film, which is usually made of multiple sets of low-reflectivity and high-reflectivity materials overlapped. During coating, due to the obstruction of the edge of the coating machine's carrier ring, the thickness of the reflective film at the edge of the wafer will be thinner than in the middle, causing color difference; at the same time, during the subsequent die bonding, a thin film thickness is more likely to break the die.

[0003] Currently, the above problems are usually solved by combining manual sorting with automatic optical inspection equipment. However, there is a certain risk of missing products through manual sorting, and the labor cost is high, and a certain proportion of abnormal products will be shipped to the client. In addition, the accuracy of existing automatic optical inspection equipment is unable to completely identify the abnormal color difference of grains. Summary of the invention

[0004] In view of the above-mentioned deficiencies in the prior art, the purpose of the present application is to provide a method and system for screening grain color difference abnormalities, and a computer-readable storage medium, aiming to solve the grain color difference caused by the above-mentioned reflective film coating.

[0005] A method for screening abnormal grain color difference, the method comprising:

[0006] Providing a wafer to be tested;

[0007] Performing image scanning on all the grains to be tested on the wafer to be tested;

[0008] Comparing the acquired image data of each of the to-be-tested grains with the preset image data for similarity;

[0009] Marking the image data with a similarity greater than a preset threshold as grains with normal appearance; wherein the area where the grains with normal appearance are located is recorded as the area to be screened; and

[0010] The grains within a preset number of circles at the edge of the area to be screened are marked as grains with abnormal color difference.

[0011] The above-mentioned method for screening grain color difference abnormalities preliminarily screens out grains with unqualified appearance by first performing image scanning and comparison, and then performs color difference screening on grains that have passed the appearance inspection, specifically, the grains within a preset number of circles at the edge of the area to be screened are regarded as grains with abnormal color difference. Since the appearance inspection can only realize the similarity comparison of the appearance of the grains, but cannot realize the judgment of color difference, the present application adds the step of automatic buckling after the appearance inspection and comparison to realize the automatic screening of color difference grains, avoid the problems of missed selection in manual selection, shipment of missed grains to customers, and high costs, and reduce unnecessary customer complaints caused by such problems.

[0012] In one embodiment, the preset threshold value ranges from 85% to 95%.

[0013] In one embodiment, the preset number of turns ranges from 3 turns to 5 turns.

[0014] In one embodiment, it further includes:

[0015] An electrical property test is performed on all the grains with normal appearance in the area to be screened except for the grains with abnormal color difference.

[0016] In one embodiment, it further includes:

[0017] The normal-looking grains marked as abnormal grains with different colors are removed.

[0018] In one embodiment, the die to be tested is a Mini LED die or a Micro LED die.

[0019] In one embodiment, the step of performing image scanning on all the dies to be tested on the wafer to be tested comprises:

[0020] An automatic optical inspection device is used to perform image scanning on all the grains to be tested on the wafer to be tested.

[0021] Based on the same inventive concept, the present application also provides a grain color difference abnormal screening system, comprising:

[0022] An image scanning module is used to perform image scanning on all the grains to be tested on the wafer to be tested;

[0023] An image comparison unit, used for comparing the acquired image data of each of the to-be-tested grains with preset image data for similarity;

[0024] A first marking unit, used for marking image data with a similarity greater than a preset threshold as grains with normal appearance;

[0025] The second marking unit is used to mark the grains with normal appearance within a preset number of circles at the edge of the area to be screened as grains with abnormal color difference.

[0026] The above-mentioned grain color difference abnormal screening system performs image scanning on all the grains to be tested on the wafer to be tested by setting an image scanning module. The image comparison unit compares the image data of each grain to be tested with the preset image data for similarity. The first marking unit marks the image data with a similarity greater than a preset threshold as grains with normal appearance. The second marking unit marks the grains with normal appearance within a preset number of circles at the edge of the area to be screened as grains with abnormal color difference. Automatic screening of grains with color difference can be achieved, avoiding the problems of missed selection in manual selection, shipping of missed grains to customers, and high costs, and reducing unnecessary customer complaints caused by such problems.

[0027] In one embodiment, the preset threshold value ranges from 85% to 95%, and the preset number of turns ranges from 3 to 5 turns.

[0028] Based on the same inventive concept, the present application also provides a computer-readable storage medium on which a computer program is stored. When the computer program is executed by a processor, it can be used to execute the method described above. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 Schematic diagram of a process for screening a grain color difference abnormality in one embodiment;

[0030] Figure 2 is a schematic flow chart of a method for screening abnormal grain color difference in another embodiment;

[0031] Figure 3 A schematic diagram of a module of a grain color difference abnormal screening system in one embodiment;

[0032] Figure 4 is a schematic structural diagram of a wafer in an embodiment;

[0033] Figure 5 for Figure 4 A local enlarged schematic diagram of the .

[0034] Description of reference numerals:

[0035] 10-image scanning module; 20-image comparison unit; 30-first marking unit; 40-second marking unit; A-magnification area; WF-wafer to be tested; W1-blocking area; A1-abnormal appearance area; A2-abnormal color difference area; A3-normal area. DETAILED DESCRIPTION

[0036] In order to facilitate the understanding of the present application, the present application will be described more fully below with reference to the relevant drawings. The preferred embodiments of the present application are given in the drawings. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present application more thoroughly and comprehensively understood.

[0037] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0038] It should be understood that spatial relationship terms such as "under", "below", "below", "under", "above", "above", etc., can be used here to describe the relationship between an element or feature shown in the figures and other elements or features. It should be understood that in addition to the orientations shown in the figures, spatial relationship terms also include different orientations of the device in use and operation. For example, if the device in the accompanying drawings is turned over, the elements or features described as "under other elements" or "under" or "under" will be oriented as "on" other elements or features. Therefore, the exemplary terms "under" and "under" can include both upper and lower orientations. In addition, the device can also include additional orientations (e.g., rotated 90 degrees or other orientations), and the spatial descriptors used herein are interpreted accordingly.

[0039] When used herein, the singular forms "a", "an", and "said / the" may also include plural forms, unless the context clearly indicates otherwise. It should also be understood that when the terms "consisting of" and / or "comprising" are used in this specification, the presence of the features, integers, steps, operations, elements and / or parts can be determined, but the presence or addition of one or more other features, integers, steps, operations, elements, parts and / or groups is not excluded. At the same time, when used herein, the term "and / or" includes any and all combinations of the relevant listed items.

[0040] As used herein, a "deposition" process includes, but is not limited to, physical vapor deposition (PVD), chemical vapor deposition (CVD), or atomic layer deposition (ALD).

[0041] Embodiments of the invention are described herein with reference to cross-sectional views which are schematic diagrams of ideal embodiments (and intermediate structures) of the invention, such that variations in the shapes shown due to, for example, manufacturing techniques and / or tolerances are anticipated. Thus, embodiments of the invention should not be limited to the specific shapes of the regions shown herein, but rather include deviations in shapes due to, for example, manufacturing techniques. For example, an implanted region shown as a rectangle typically has rounded or curved features and / or an implant concentration gradient at its edges rather than a binary change from an implanted region to a non-implanted region. Similarly, a buried region formed by implantation may result in some implantation in the region between the buried region and the surface through which the implantation is performed. Thus, the regions shown in the figures are schematic in nature, their shapes do not represent the actual shape of the region of the device, and do not limit the scope of the invention.

[0042] As described in the background of this application, in the traditional LED manufacturing process, it is usually necessary to coat the non-light-emitting side with a reflective film, which is usually made of multiple sets of overlapping low-reflectivity and high-reflectivity materials. During the coating process, due to the obstruction of the edge of the coating machine's carrier ring, the thickness of the reflective film at the edge of the wafer will be thinner than in the middle, causing color difference; at the same time, during the subsequent solidification, the thin film thickness is more likely to break the grain.

[0043] Currently, the above problems are usually solved by combining manual sorting with automatic optical inspection equipment. However, there is a certain risk of missing products through manual sorting, and the labor cost is high, and a certain proportion of abnormal products will be shipped to the client. In addition, the accuracy of existing automatic optical inspection equipment is unable to completely identify the abnormal color difference of grains.

[0044] Please refer to Figure 4 Taking Mini LED products as an example, the inventors found in actual operation that the blue-green light wafer will have color difference in the area about 1-2mm away from its edge (i.e. W1 area), and the color difference is mainly due to the edge of the coating machine carrier ring blocking, resulting in the edge film thickness being thinner than the middle. Figure 5 As shown, the grains in the abnormal appearance area A1 can be screened out by automatic optical inspection equipment, while the abnormal color area A2 can only be selected manually. Manual selection may have the risk of missing, resulting in a certain proportion of abnormal products being shipped to the client, causing customer complaints.

[0045] Based on this, the present application hopes to provide a solution that can solve the above-mentioned technical problems, the details of which will be described in the subsequent embodiments.

[0046] Please refer to Figure 1 , a method for screening abnormal grain color difference provided in the present application, the method may include steps S100-S500.

[0047] Step S100, providing a wafer to be tested;

[0048] Step S200, performing image scanning on all the dies to be tested on the wafer to be tested;

[0049] Step S300, comparing the acquired image data of each of the to-be-tested grains with preset image data for similarity;

[0050] Step S400, marking the image data with a similarity greater than a preset threshold as grains with normal appearance; wherein the area where the grains with normal appearance are located is recorded as an area to be screened; and

[0051] Step S500 marks the grains within a preset number of circles at the edge of the to-be-screened area as grains with abnormal color difference.

[0052] The above-mentioned method for screening grain color difference abnormalities preliminarily screens out grains with unqualified appearance by first performing image scanning and comparison, and then performs color difference screening on grains that have passed the appearance inspection, specifically, the grains within a preset number of circles at the edge of the area to be screened are regarded as grains with abnormal color difference. Since the appearance inspection can only realize the similarity comparison of the appearance of the grains, but cannot realize the judgment of color difference, the present application adds the step of automatic buckling after the appearance inspection and comparison to realize the automatic screening of color difference grains, avoid the problems of missed selection in manual selection, shipment of missed grains to customers, and high costs, and reduce unnecessary customer complaints caused by such problems.

[0053] Specifically, the wafer to be tested WF provided in the present application may be a COT (Chip On Tape), that is, a conventional wafer is placed on a blue film after being ground, cut, split, and expanded.

[0054] The automatic optical inspection device can be used to perform image scanning on all the grains to be tested on the wafer WF to obtain image data of each grain to be tested. Subsequently, all the acquired image data can be analyzed and compared with the preset standard image. The preset standard image can be pre-stored in the automatic optical inspection device, and the image comparison can be performed by the automatic optical inspection device; the preset standard image can also be stored in the host computer, and the image data returned by the automatic optical inspection device can be compared and analyzed by the host computer. In this specific embodiment, if the similarity of the aforementioned analysis and comparison exceeds the preset threshold, the corresponding grain to be tested is marked as a grain with normal appearance, otherwise, it is a grain with defective appearance. Exemplarily, the preset threshold of the present application ranges from 85% to 95%. It is understandable that the preset threshold can be selected from 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, and 95%; or it can be selected from 85.5%, 86.5%, 87.5%, 88.5%, 89.5%, 90.5%, 91.5%, 92.5%, 93.5%, and 94.5%. The present application does not impose any further restrictions on this. It is understandable that the setting and recognition ability of the similarity are mainly related to the accuracy of the image sensor of the automatic optical inspection equipment. Those skilled in the art can customize it according to actual needs and machine debugging results. It should be pointed out that too low similarity will increase the probability of misjudgment of abnormal grains. Furthermore, the grains to be tested in the present application can be Mini LED grains or Micro LED grains.

[0055] You can continue to read Figure 5 After the normal-looking grains are determined, the area where these normal-looking grains are located can be marked as the area to be screened (i.e. Figure 5 A2+normal area A3 in the W1 region), and then, on this basis, the grains with normal appearance in the area to be screened can be further screened. Specifically, the grains within the preset number of circles at the edge of the area to be screened are marked as abnormal grains with different colors. In this specific embodiment, the optional preset number of circles ranges from 3 to 5 circles. According to the above description, the width of the W1 region is approximately 1-2mm, and the width of the region is usually floating, so the basis for buckling the circle is still determined by the actual scanning results mentioned above. In summary, the inventor found that after the appearance screening, buckling 3-5 circles can basically screen out all abnormal grains with different colors. It can be understood that the number of circles or circles mentioned in this application are concentric circles formed with the geometric center of the wafer as the origin; buckling circles refer to the deduction of the corresponding number of circles from the edge of the wafer along the center. Further, for different grain sizes and wafer sizes, the range of the above number of circles may have certain fluctuations and adjustments, but it is mainly determined by the scanning situation. Those skilled in the art can select and adjust according to the actual situation, and this application does not make further restrictions on this.

[0056] Please refer to Figure 2 , is a flow chart of a method for screening grain color difference abnormality in another embodiment provided by the present application. The difference between this method and the aforementioned method is that steps S600-S700 are newly added. Therefore, the description of steps S100-S500 is not repeated here, and reference may be made to the aforementioned.

[0057] Specifically, in step S600, electrical test is performed on all the grains with normal appearance except the grains with abnormal color difference in the area to be screened.

[0058] The electrical test can be performed, for example, using a dedicated electrical test machine, or a test machine integrated into an automatic optical inspection device, and this application does not further limit this. Since this step only tests the dies without color difference during the electrical test, the test volume and test cost can be reduced, and the test efficiency can be improved.

[0059] Specifically, in step S700 , the grains with normal appearance that are marked as grains with abnormal color difference are removed.

[0060] By removing the normal-looking dies marked as dies with abnormal color, the problem of dies with abnormal color being shipped to customers and causing customer complaints can be reduced or avoided.

[0061] Based on the same inventive concept, Figure 3 , is a module structure diagram of the grain color difference abnormal screening system provided in the present application. The grain color difference abnormal screening system may include: an image scanning module 10, an image comparison unit 20, a first marking unit 30, and a second marking unit 40.

[0062] Among them, the image scanning module 10 is used to perform image scanning on all the grains to be tested on the wafer WF to be tested; the image comparison unit 20 is used to compare the acquired image data of each of the grains to be tested with the preset image data for similarity; the first marking unit 30 is used to mark the image data with a similarity greater than a preset threshold as grains with normal appearance; the second marking unit 40 is used to mark the grains with normal appearance within a preset number of circles at the edge of the area to be screened as grains with abnormal color difference.

[0063] The above-mentioned grain color difference abnormal screening system performs image scanning on all the grains to be tested on the wafer to be tested by setting an image scanning module. The image comparison unit compares the image data of each grain to be tested with the preset image data for similarity. The first marking unit marks the image data with a similarity greater than a preset threshold as grains with normal appearance. The second marking unit marks the grains with normal appearance within a preset number of circles at the edge of the area to be screened as grains with abnormal color difference. Automatic screening of grains with color difference can be achieved, avoiding the problems of missed selection in manual selection, shipping of missed grains to customers, and high costs, and reducing unnecessary customer complaints caused by such problems.

[0064] It can be understood that for further understanding of the functions of each module in this specific embodiment, reference can be made to the description of the aforementioned method embodiment, and this application will not further elaborate on this.

[0065] In one embodiment, the preset threshold value ranges from 85% to 95%, and the preset number of turns ranges from 3 to 5 turns.

[0066] Based on the same inventive concept, the present application also provides a computer-readable storage medium on which a computer program is stored. When the computer program is executed by a processor, it can be used to execute the method described above.

[0067] The computer-readable storage medium stores a program that can execute the aforementioned method for screening grain color difference abnormalities. The method preliminarily screens out grains with unqualified appearance by first performing image scanning and comparison, and then performs color difference screening on grains that have passed the appearance inspection. Specifically, the grains within a preset number of circles at the edge of the area to be screened are regarded as grains with abnormal color difference. Since the appearance inspection can only compare the similarity of the appearance of the grains, but cannot judge the color difference, the present application adds an automatic buckling step after the appearance inspection and comparison to achieve automatic screening of color difference grains, avoid the problems of missed selection in manual selection, shipment of missed grains to customers, and high costs, and reduce unnecessary customer complaints caused by such problems.

[0068] Optionally, the computer-readable storage medium may include a volatile memory (English: Volatile Memory), such as a random access memory (English: Random-Access Memory, abbreviated: RAM), such as a static random access memory (English: Static Random-Access Memory, abbreviated: SRAM), a double data rate synchronous dynamic random access memory (English: Double Data Rate Synchronous Dynamic Random Access Memory, abbreviated: DDR SDRAM), etc.; the memory may also include a non-volatile memory (English: Non-Volatile Memory), such as a flash memory (English: Flash Memory). The memory is used to store computer programs (such as applications, functional modules, etc. that implement the above method), computer instructions, etc., and the above computer programs, computer instructions, etc. can be partitioned and stored in one or more memories. And the above computer programs, computer instructions, data, etc. can be called by the processor.

[0069] The above-mentioned computer programs, computer instructions, etc. may be stored in one or more memories in partitions, and the above-mentioned computer programs, computer instructions, data, etc. may be called by a processor.

[0070] The processor is used to execute the computer program stored in the memory to implement the various steps in the method involved in the above embodiment. For details, please refer to the relevant description in the above method embodiment.

[0071] The processor and the memory may be independent structures or integrated structures. When the processor and the memory are independent structures, the memory and the processor may be coupled and connected via a bus.

[0072] It should be understood that the application of the present invention is not limited to the above examples. For ordinary technicians in this field, improvements or changes can be made based on the above description. All these improvements and changes should fall within the scope of protection of the claims attached to the present invention.

Claims

1. A method for screening abnormal grain color difference, characterized in that: The method comprises: Providing a wafer to be tested; Performing image scanning on all the grains to be tested on the wafer to be tested; Comparing the acquired image data of each of the to-be-tested grains with the preset image data for similarity; Marking the image data with a similarity greater than a preset threshold as grains with normal appearance; wherein the area where the grains with normal appearance are located is recorded as the area to be screened; and The grains within a preset number of circles at the edge of the area to be screened are marked as grains with abnormal color difference.

2. The method for screening abnormal grain color difference according to claim 1, characterized in that: The preset threshold value ranges from 85% to 95%.

3. The method for screening abnormal grain color difference according to claim 1, characterized in that: The preset number of revolutions ranges from 3 revolutions to 5 revolutions.

4. The method for screening abnormal grain color difference according to claim 1, characterized in that: Also includes: An electrical property test is performed on all the grains with normal appearance in the area to be screened except for the grains with abnormal color difference.

5. The method for screening abnormal grain color difference according to claim 1, characterized in that: Also includes: The normal-looking grains marked as abnormal grains with different colors are removed.

6. The method for screening abnormal grain color difference according to any one of claims 1 to 5, characterized in that: The die to be tested is a Mini LED die or a Micro LED die.

7. The method for screening abnormal grain color difference according to any one of claims 1 to 5, characterized in that: The step of performing image scanning on all the grains to be tested on the wafer to be tested comprises: An automatic optical inspection device is used to perform image scanning on all the grains to be tested on the wafer to be tested.

8. A grain color difference abnormal screening system, characterized in that: include: An image scanning module is used to perform image scanning on all the grains to be tested on the wafer to be tested; An image comparison unit, used for comparing the acquired image data of each of the to-be-tested grains with preset image data for similarity; A first marking unit, used for marking image data with a similarity greater than a preset threshold as grains with normal appearance; The second marking unit is used to mark the grains with normal appearance within a preset number of circles at the edge of the area to be screened as grains with abnormal color difference.

9. The grain color difference abnormal screening system according to claim 8, characterized in that: The preset threshold value has a value range of 85% to 95%, and the preset number of turns has a value range of 3 to 5 turns.

10. A computer-readable storage medium, characterized in that: A computer program is stored thereon, and when the computer program is executed by a processor, it can be used to execute the method according to any one of claims 1 to 7.

Images