Defect detection method and device, computer readable storage medium and electronic device

Abstract

The disclosure provides a defect detection method and device, a computer readable storage medium and an electronic device, and relates to the technical field of semiconductors. The defect detection method comprises: selecting a plurality of dies as sample dies from a wafer to be measured; wherein the wafer to be measured comprises a plurality of dies; determining the median of the gray scale of a position point in the same area of a plurality of sample dies in units of pixels; setting at least one reference die; wherein the gray scale value of the corresponding same position point of the reference die is the median in units of pixels; comparing the reference die with each die in the wafer to be measured one by one, and determining whether each die in the wafer to be measured has a defect according to the comparison result. The technical problem that the effect of the current defect detection method is poor is solved, and the defect detection effect is improved.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the technical field of semiconductor, and particularly relates to a defect detection method and device, a computer readable storage medium and an electronic device. BACKGROUND

[0002] In the actual production process of semiconductors, some product defects are caused by errors in equipment and processes, and therefore, semiconductor defect detection is an essential step in the actual production process. At present, the detection of wafer defects in semiconductors mainly adopts random mode detection: each die in the wafer is scanned, the difference between two adjacent dies is calculated during the scanning process, and the difference is determined as a defect.

[0003] This detection method is mainly suitable for defects that are relatively obvious and have large defect differences. Once the defect differences in some areas are small, it is difficult to detect them.

[0004] Therefore, the current defect detection method has poor effect. SUMMARY

[0005] The present disclosure provides a defect detection method, device, computer readable storage medium and electronic device, thereby improving the defect detection effect.

[0006] In a first aspect, an embodiment of the present disclosure provides a defect detection method, comprising:

[0007] selecting a plurality of dies from a wafer to be tested as sample dies; wherein the wafer to be tested comprises a plurality of dies;

[0008] determining the median of the gray scale values of the position points in the same area of the plurality of sample dies in units of pixels;

[0009] setting at least one reference die; wherein the gray scale value of the corresponding position points of the reference die is the median of the gray scale values in units of pixels;

[0010] comparing the reference die with each die in the wafer to be tested one by one, and determining whether each die in the wafer to be tested has a defect according to the comparison result.

[0011] In an optional embodiment of the present disclosure, any column or any row of dies in the wafer to be tested is selected as the sample dies.

[0012] In an optional embodiment of the present disclosure, determining the median of the gray scale values of the position points in the same area of the plurality of sample dies comprises:

[0013] detecting the gray scale values of the position points in the same area of each sample die to obtain a plurality of first gray scale values;

[0014] Calculate a median of the plurality of first gray scale values to obtain a gray scale median.

[0015] In an optional embodiment of the present disclosure, the gray scale value detection is performed on the position points in the same region of each sample die to obtain a plurality of first gray scale values, including:

[0016] The gray scale value detection is performed on each same position point in each sample die to obtain a plurality of first gray scale values.

[0017] In an optional embodiment of the present disclosure, at least one reference die is set, including:

[0018] Obtaining a preset structure parameter of each die in the to-be-tested wafer;

[0019] Constructing at least one reference die based on the preset structure parameter and the gray scale median; wherein the gray scale value of the corresponding same position point of the reference die is the gray scale median.

[0020] In an optional embodiment of the present disclosure, at least one reference die is set, including:

[0021] The gray scale value detection is performed on the position points in the same region of each die in the to-be-tested wafer to obtain a plurality of second gray scale values;

[0022] The difference between each second gray scale value and the gray scale median is determined respectively;

[0023] The die constructed based on the second gray scale value with the minimum difference is determined as the reference die.

[0024] In an optional embodiment of the present disclosure, the gray scale value detection is performed on the position points in the same region of each die in the to-be-tested wafer to obtain a plurality of second gray scale values, including:

[0025] The gray scale value detection is performed on each same position point in each die in the to-be-tested wafer to obtain a plurality of second gray scale values.

[0026] In an optional embodiment of the present disclosure, after at least one reference die is set, the method further includes:

[0027] Obtaining a preset structure parameter of each die in the to-be-tested wafer;

[0028] Determining an actual structure parameter of the reference die;

[0029] Determining a structure difference between the preset structure parameter and the actual structure parameter;

[0030] If the structure difference is within a preset difference range, the reference die is determined as a target reference die.

[0031] In an optional embodiment of the present disclosure, after at least one reference die is set, the method further includes:

[0032] If the structural difference is out of the preset difference range, a plurality of dies are reselected from the wafer under test as new sample dies;

[0033] A new reference die is re-determined according to the new sample dies;

[0034] A new actual structural parameter of the new reference die is determined;

[0035] If the new actual structural parameter and the new structural difference of the preset structural parameter are within the preset difference range, the new reference die is determined as the target reference die.

[0036] In an optional embodiment of the present disclosure, the structural parameter includes a critical dimension parameter and a position coordinate parameter.

[0037] In an optional embodiment of the present disclosure, the die is a chip.

[0038] In an optional embodiment of the present disclosure, the reference die is compared with each die in the wafer under test one by one, and whether each die in the wafer under test has a defect is determined according to a comparison result, including:

[0039] A reference gray scale map corresponding to the reference die and an actual gray scale map corresponding to each die in the wafer under test are acquired respectively;

[0040] The reference gray scale map and the actual gray scale map are compared, and whether each die in the wafer under test has a defect is determined according to a comparison result.

[0041] In an optional embodiment of the present disclosure, the reference gray scale map and the actual gray scale map are compared, including:

[0042] The position points in the same area in the reference gray scale map and the actual gray scale map are compared.

[0043] In an optional embodiment of the present disclosure, the reference gray scale map and the actual gray scale map are compared, and whether each die in the wafer under test has a defect is determined according to a comparison result, including:

[0044] The die at the same position point in the reference gray scale map and the actual gray scale map and having a gray scale value difference exceeding a preset threshold is determined as a defective die.

[0045] In a second aspect, an embodiment of the present disclosure provides a defect detection device, including:

[0046] A sample die selection module is configured to select a plurality of dies from a wafer under test as sample dies; wherein the wafer under test includes a plurality of dies;

[0047] A determination module is configured to determine, in units of pixels, a median of gray scales of position points in a same area of the plurality of sample dies.

[0048] The reference grain setting module is configured to set at least one reference grain, wherein a gray scale value of a same position point of the reference grain in a pixel unit is a gray scale median value.

[0049] The comparison module is configured to compare each grain in the wafer under test with the reference grain one by one, and determine whether each grain in the wafer under test has a defect according to a comparison result.

[0050] In a third aspect, an embodiment of the present disclosure provides a computer readable storage medium having a computer program stored thereon, and the computer program is executed by a processor to implement the method of any one of the above.

[0051] In a fourth aspect, an embodiment of the present disclosure provides an electronic device, comprising:

[0052] a processor; and

[0053] a memory configured to store executable instructions of the processor;

[0054] The processor is configured to execute the method of any one of the above by executing the executable instructions.

[0055] The technical solution of the present disclosure has the following beneficial effects:

[0056] The above defect detection method first selects a plurality of grains from the wafer under test as sample grains, then sets at least one reference grain based on the gray scale median value of the position points in the same area of the plurality of sample grains, and finally compares each grain in the wafer under test with the reference grain one by one, so as to determine whether each grain in the wafer under test has a defect. The embodiment of the present disclosure compares each grain with the reference grain based on the gray scale median value of the plurality of sample grains, even if there is a similar or identical defect in a certain area, the comparison based on the reference grain can easily detect the defect, and the traditional method of comparing two adjacent grains cannot detect the defect with small difference, thereby solving the technical problem that the current defect detection method has poor effect, and achieving the technical effect of improving the defect detection effect.

[0057] It should be understood that the above general description and the following detailed description are only exemplary and explanatory, and cannot limit the present disclosure. BRIEF DESCRIPTION OF DRAWINGS

[0058] The accompanying drawings, which are incorporated herein and form a part of the specification, illustrate the embodiments of the present disclosure and, together with the description, further serve to explain the principles of the present disclosure. It is to be understood that the drawings are only schematic, and that they do not purport to be to scale with respect to one another. The embodiments of the present disclosure will be described with reference to the drawings, together with the following detailed description, wherein like elements are referred to with like reference numerals.

[0059] Figure 1 A schematic diagram of a current defect detection in the present exemplary embodiment is shown;

[0060] Figure 2 A scanning electron microscope (SEM) image in a current defect detection in the present exemplary embodiment is shown;

[0061] Figure 3 A flowchart of a defect detection method in the present exemplary embodiment is shown;

[0062] Figure 4 A schematic diagram of selecting sample dies from a wafer under test in a defect detection method in the present exemplary embodiment is shown;

[0063] Figure 5 A flowchart of a defect detection method in the present exemplary embodiment is shown;

[0064] Figure 6 A flowchart of a defect detection method in the present exemplary embodiment is shown;

[0065] Figure 7 A flowchart of a defect detection method in the present exemplary embodiment is shown;

[0066] Figure 8 A flowchart of a defect detection method in the present exemplary embodiment is shown;

[0067] Figure 9 A flowchart of a defect detection method in the present exemplary embodiment is shown;

[0068] Figure 10 A scanning electron microscope (SEM) image and corresponding gray scale data in a defect detection in a defect detection method in the present exemplary embodiment are shown;

[0069] FIG. 11(a) shows a gray scale data of a reference die in a defect detection method in the present exemplary embodiment;

[0070] FIG. 11(b) shows a gray scale data of each die in a wafer under test in a defect detection method in the present exemplary embodiment;

[0071] FIG. 11(c) shows a gray scale comparison data of a reference die and each die in a wafer under test in a defect detection method in the present exemplary embodiment;

[0072] Figure 12 Fig. 1 shows a schematic diagram of a defect detection device according to an example embodiment;

[0073] Figure 13 Fig. 1 shows a schematic diagram of a defect detection device according to an example embodiment; DETAILED DESCRIPTION

[0074] Example embodiments now will be described more fully hereinafter with reference to the accompanying drawings. Example embodiments, however, can be implemented in many different forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the example embodiments to those skilled in the art. Like reference numerals refer to like elements throughout. The terminology used in the description presented herein is not intended to be interpreted in any specific and / or particular manner. The terminology utilized in the present disclosure is for the purpose of describing particular example embodiments only and is not intended to be limiting. The use of the terms "example" and / or "exemplary" is intended to present concepts in a particular manner and is not intended to be limiting. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items. Expressions such as "at least one of," when preceding the syllables of a list of elements, modify the entire list of elements and do not modify the elements individually.

[0075] In addition, the drawings are to be regarded as being schematic and are not necessarily drawn to scale. The same reference numerals in different drawings denote the same or similar functionality. Repetitive descriptions of like elements presented in separate instances can be omitted for clarity. Some of the blocks in the flowcharts shown in the drawings can be functional blocks that can not necessarily have a corresponding physical or logical entity in an implantation. These functional blocks can be implemented by software, or in one or more hardware modules or integrated circuits, or in different network and / or processor devices and / or microcontroller devices.

[0076] The flowcharts shown in the drawings are merely illustrative and do not necessarily include all steps. For example, some steps can be further divided, and some steps can be combined or partially combined, so that the actual execution order can be changed according to the actual situation.

[0077] In the related art, some product defects are caused by equipment, process, and other errors in the actual production process of semiconductors, and therefore, semiconductor defect detection is an essential step in the actual production process. At present, the detection of wafer defects in semiconductors mainly uses random mode detection: each die in the wafer is scanned, the difference between two adjacent dies is calculated during the scanning process, and the difference is determined as a defect. This detection method is mainly suitable for defects that are more obvious and have larger defect differences. Once the defect differences in some areas are small, it is difficult to detect them.

[0078] For example, see Figure 1 , Figure 1 (a), Figure 1 (b) and Figure 1 (c) are schematic diagrams of three adjacent dies on a wafer, wherein Figure 1 (a) has a triangular defect, Figure 1 (b) has an irregular defect, Figure 1 (c) has no obvious defect. The current defect detection method is generally to compare Figure 1 (a) with Figure 1 (b) to obtain the difference between the two, including a triangular foreign matter and an irregular foreign matter; then compare Figure 1 (b) with Figure 1 (c) to obtain the difference between the two, including an irregular foreign matter; finally, compare the triangular foreign matter and the irregular foreign matter obtained in the first detection with the irregular foreign matter obtained in the second detection, and find that the irregular foreign matter is repeatedly present, so the irregular foreign matter is determined as a defect; and the other triangular defect does not repeatedly appear, so it is determined as a non-defect. However, both the triangular foreign matter and the irregular foreign matter belong to defects, and this detection method can easily lead to the detection of some defects with small differences, such as the triangular defect described above.

[0079] Please continue to see Figure 2 , Figure 2 (a) is an electron microscope scanning diagram of a whole wafer, including a plurality of dies arranged in a matrix, Figure 2 (b), Figure 2 (c) and Figure 2 (d) are local electron microscope scanning diagrams of different positions on the wafer. It can be clearly observed that Figure 2 (b) the scanning diagrams of two adjacent dies are almost the same, and it is difficult to detect the difference between the two; similarly, the difference between 2(c) and Figure 2 (d) two adjacent dies is almost impossible to determine.

[0080] Therefore, the current defect detection method has poor effect.

[0081] In view of the above problems, the embodiment of the present disclosure provides a defect detection method, first, a plurality of dies are selected from the wafer to be tested as sample dies, then at least one reference die is set based on the median of the gray scale of the plurality of sample dies, and finally, each die in the wafer to be tested is compared with the reference die one by one to determine whether each die in the wafer to be tested has a defect. The embodiment of the present disclosure is based on a gray scale value, that is, the median of the gray scale of the plurality of sample dies, and each die is compared with the reference die one by one. Even if there is a similar or identical defect in a certain area, the comparison based on the reference die can easily detect the defect, which can avoid the defect that cannot be detected by comparing the adjacent two dies in the traditional way, thereby solving the technical problem that the current defect detection method has poor effect, and achieving the technical effect of improving the defect detection effect.

[0082] The following takes any one control device as the execution subject, and takes the defect detection method provided by the embodiment of the present disclosure executed based on the control device as an example for illustration. The control device can be a server, a computer, a notebook computer, a tablet computer, or other devices with control functions, etc. The embodiment of the present disclosure is not limited specifically, and can be selected or set according to the actual situation. Please refer to Figure 3 The defect detection method provided by the embodiment of the present disclosure includes the following steps 301-304:

[0083] Step 301, selecting a plurality of dies from the wafer to be tested as sample dies.

[0084] The wafer refers to a silicon wafer used to manufacture silicon semiconductor products. After preparation, a wafer can produce a batch of semiconductor products. Correspondingly, a wafer contains a plurality of dies during preparation, and the plurality of dies can be arranged according to any rule. Correspondingly, the wafer to be tested in the embodiment of the present disclosure also contains a plurality of dies. The wafer to be tested in the embodiment of the present disclosure can be a wafer of any electronic element, such as a capacitor, a resistor, a mosfet tube (Metal Oxide Semiconductor Field Effect Transistor, metal oxide semiconductor field effect transistor), etc. The embodiment of the present disclosure is not limited specifically, and can be selected or set according to the actual situation.

[0085] Step 302, determining the median of the gray scale of the position points in the same area of the plurality of sample dies in units of pixels.

[0086] The region referred to in the embodiment is the outer surface of the crystal grain, and the same region refers to regions at the same position in multiple crystal grains, such as a central region of a first crystal grain, a central region of a second crystal grain, and a central region of a third crystal grain, which are at the same region. Correspondingly, the center point of the first crystal grain, the center point of the second crystal grain, and the center point of the third crystal grain are position points in the same region. When the gray scale value of the crystal grain is determined, the pixels on the surface region of the crystal grain are detected. Therefore, the embodiment of the present disclosure determines the median gray scale of the position points in the same region in each sample crystal grain in sequence as a unit of pixel. The median gray scale refers to the median of the gray scale values of all sample crystal grains. The embodiment of the present disclosure can detect the gray scale of the multiple sample crystal grains as a whole to obtain the median gray scale, or detect the gray scale value of each sample crystal grain separately, and then select the median from the multiple detected gray scale values as the median gray scale. The embodiment of the present disclosure is not specifically limited, and can be selected or set according to the actual situation.

[0087] Step 303, setting at least one reference crystal grain.

[0088] The reference crystal grain is a reference for defect detection of all crystal grains in the wafer to be measured. The reference crystal grain can be a reconstructed virtual crystal grain, or a crystal grain selected from the wafer to be measured. The embodiment of the present disclosure is not specifically limited, but it is emphasized that the gray scale value of the same position point of the reference crystal grain in units of pixels is the median gray scale.

[0089] Step 304, comparing the reference crystal grain with each crystal grain in the wafer to be measured one by one, and determining whether each crystal grain in the wafer to be measured has a defect according to the comparison result.

[0090] The reference crystal grain is a reference selected from the wafer to be measured. The reference can be compared with other crystal grains in the wafer to be measured one by one. The comparison method can be one-to-one comparison of the spectrum obtained by scanning with an electron microscope, or one-to-one comparison using other detection platforms, etc. The embodiment of the present disclosure is not specifically limited, and can be selected or set according to the actual situation.

[0091] The defect detection method provided in this disclosure first selects multiple grains from the wafer under test as sample grains. Then, it sets at least one reference grain based on the median grayscale value of these sample grains. Finally, it performs a feature comparison between the reference grain and each grain in the wafer under test to determine whether any defects exist in each grain. This disclosure method compares each grain with a reference grain whose grayscale value is the median grayscale value of the sample grains. Even if similar or identical defects exist in a certain area, they can be easily detected based on the comparison with the reference grain. This avoids the problem of failing to detect small differences in defects by comparing adjacent grains in traditional methods, thus solving the technical problem of poor performance in current defect detection methods and improving the defect detection effect. Furthermore, this disclosure method can perform a one-to-one comparison of all grains in the wafer under test based on the obtained reference grain to achieve defect detection for all grains, thus broadening its applicability and further improving the applicability of the defect detection method in this disclosure.

[0092] In one optional embodiment of this disclosure, please refer to Figure 4 The wafer under test contains multiple grains arranged in a matrix, meaning that the grains in the wafer under test are arranged in a regular matrix. Correspondingly, step 301 above, selecting multiple grains from the wafer under test as sample grains, includes the following steps:

[0093] Select any column or row of the wafer matrix to be tested as the sample grain.

[0094] For example from Figure 4 A column or any row of grains 401 is selected from the wafer. The grains in this column or row are used as sample grains to determine the median gray level, and reference grains are further constructed. It should be explained that this embodiment does not limit which column or row of grains is selected as the sample grains, or the number of sample grains, etc., and can be selected or set according to the actual situation. At the same time, the column (row) referred to in this embodiment does not mean that selection can only be made in the vertical (horizontal) direction and not in the horizontal (vertical) direction. In this embodiment, a column or row refers to a group of grains interconnected on the wafer to be tested.

[0095] This embodiment of the present disclosure selects a column or row of interconnected cells as sample dies. Dies in the same column or row have basically the same processing status at each process node, and the possible defects are also similar. Therefore, this embodiment of the present disclosure selects a column or row of interconnected cells in the wafer under test as sample dies, which can improve the universality of the reference die constructed based on the median gray level of the multiple sample dies, and further improve the reliability of defect detection based on the comparison between the reference die and each die.

[0096] See Figure 5 In an optional embodiment of the present disclosure, the step 302 of determining the median gray scale of the position points in the same region of the plurality of sample grains includes the following steps 501-502:

[0097] The step 501 is to detect the gray scale values of the position points in the same region of each sample grain to obtain a plurality of first gray scale values.

[0098] The first gray scale value refers to the gray scale value of each sample grain, which can be measured by electron microscope scanning comparison method, fluorescence test method, etc., and the embodiments of the present disclosure do not exhaustively list them, and the actual situation can be specifically selected.

[0099] The step 502 is to calculate the median of the plurality of first gray scale values to obtain the median gray scale.

[0100] The median gray scale is also the median value of the plurality of first gray scale values.

[0101] The embodiments of the present disclosure first detect the gray scale values of each sample grain to obtain a plurality of first gray scale values, and then determine the median gray scale from the plurality of first gray scale values. The median gray scale obtained has higher accuracy than the average value obtained by comprehensive detection of the plurality of sample grains, which can improve the reliability of the median gray scale, improve the universality of the reference grain constructed based on the median gray scale, and further improve the reliability of the defect detection based on the comparison between the reference grain and each grain.

[0102] In an optional embodiment of the present disclosure, the step 501 of detecting the gray scale values of the position points in the same region of each sample grain to obtain a plurality of first gray scale values includes the following steps:

[0103] The gray scale values of each same position point in each sample grain are detected to obtain a plurality of first gray scale values.

[0104] The same position in the embodiments of the present disclosure refers to the same position in each grain, for example, the center position in the first grain, and the center position in other grains. Correspondingly, if it is in the lower left corner position in the first grain, it is also in the lower left corner position in other grains. Similarly, it is only necessary to ensure that the gray scale values of the same position in each sample grain are detected to obtain the first gray scale values of the same position in each sample grain. The corresponding first gray scale value is the gray scale value of the same position in each sample grain. The embodiments of the present disclosure detect the gray scale values of the same position in each sample grain to obtain the first gray scale values, so that the reference grain determined based on the first gray scale values has stronger reference, and the reliability of the defect detection method provided by the embodiments of the present disclosure is further improved.

[0105] SeeFigure 6 In an optional embodiment of the present disclosure, the step 303 of setting at least one reference die includes the following steps 601-602:

[0106] The step 601 is to obtain preset structure parameters of each die in the wafer to be tested.

[0107] The preset structure parameters refer to structure parameters designed in advance for each die in the wafer to be tested, for example, any structure parameter that can represent each die, such as shape, key size parameter, position coordinate parameter, etc. The present disclosure does not make any limitation on the specific type and number of the preset structure parameters, which can be configured according to actual conditions. It should be explained that the key size parameter refers to any one of, for example, die length, width, height, thickness, bending angle, capacitor column length, width and height, pin length, width, etc. The key size can be adjusted according to the actual type of die, which is not limited here. The preset structure parameters are imported into the control device by being pre-configured and designed by the staff, and the control device can obtain the preset structure parameters.

[0108] The step 602 is to construct at least one reference die based on the preset structure parameters and the median gray scale.

[0109] For example, a die with a gray scale value of the median gray scale is obtained again through modeling or actual preparation as the reference die, which only needs to ensure that the gray scale value of the corresponding same position point of the reference die is the median gray scale.

[0110] The present embodiment first obtains the preset structure parameters of each die in the wafer to be tested, and then constructs at least one reference die with a gray scale value of the median gray scale based on the preset structure parameters and the median gray scale, completely avoiding each die in the wafer to be tested. By comparing the reference die with each die in the wafer to be tested, it is determined whether there is a defect. The comparison is more obvious, and it is easier to determine the difference between the two, thereby improving the effect of defect detection of the present embodiment.

[0111] Please refer to Figure 7 In an optional embodiment of the present disclosure, the step 303 of setting at least one reference die includes the following steps 701-703:

[0112] The step 701 is to detect the gray scale value of the same region position point in each die in the wafer to be tested to obtain a plurality of second gray scale values.

[0113] The second gray scale value refers to the gray scale value of each die in the wafer to be measured, which can be measured by electron microscope scanning comparison method, fluorescence test method, etc. The present embodiment does not exhaustively list them, and they can be selected according to actual conditions. It should be explained that the first gray scale value in the above step 501 refers to the gray scale value of the sample die, and the sample die is selected from each die in the wafer to be measured. Therefore, if the second gray scale value is obtained, it is not necessary to re-detect the gray scale value of the sample die, but to select a plurality of first gray scale values from the plurality of first gray scale values of each die as the second gray scale value.

[0114] Step 702, respectively determining the difference between the plurality of second gray scale values and the gray scale median.

[0115] The difference value is used to represent the difference between the second gray scale value and the gray scale median, that is, to represent the difference between each die in the wafer to be measured and the reference die. It should be explained that the difference value refers to a value greater than or equal to 0. If the difference is negative, the difference value is the absolute value of the negative value.

[0116] Step 703, determining the die constructed based on the second gray scale value with the smallest difference as the reference die.

[0117] The smaller the difference is, the smaller the difference between the die and the ideal die is. The present embodiment directly determines the die corresponding to the second gray scale value with the smallest difference from the gray scale median in the wafer to be measured as the reference die, without the need to re-construct a new die. It is simple and fast, and can maximize the reliability of the reference die, thereby improving the detection effect of the defect detection method provided by the present embodiment.

[0118] In an optional embodiment of the present disclosure, the above step 701, the gray scale value of each same position point in each die in the wafer to be measured is detected to obtain a plurality of second gray scale values, including the following steps:

[0119] The gray scale value of each same position point in each die in the wafer to be measured is detected to obtain a plurality of second gray scale values.

[0120] The same position in the present embodiment refers to the same position in each die, for example, the center position in the second die, and the center position in other dies. Correspondingly, if it is at the lower left corner position in the second die, it is also at the lower left corner position in other dies. Similarly, it is only necessary to ensure that the gray scale value of the same position in each die is detected to obtain the second gray scale value of the same position in each die. The corresponding second gray scale value is the gray scale value of the same position in each die. The present embodiment obtains the second gray scale value by detecting the gray scale value of the same position in each die, so that the reference die determined based on the second gray scale value has stronger reference, and further improves the reliability of the defect detection method provided by the present embodiment.

[0121] See Figure 8 In an optional embodiment of the present disclosure, after the step 303 of setting at least one reference die, the method further comprises steps 801-803 as follows:

[0122] In step 801, preset structure parameters of each die in the to-be-tested wafer are obtained.

[0123] Corresponding to the step 601, the preset structure parameters refer to structure parameters designed in advance for each die in the to-be-tested wafer, for example, any structure parameter that can represent each die, such as shape, key size parameter, position coordinate parameter, etc. The present disclosure does not make any limitation on the specific type and quantity of the preset structure parameters, which can be configured according to actual conditions. It should be explained that the key size parameter refers to any one of, for example, die length, width, height, thickness, bending angle, capacitor column length, width and height, pin length, width, etc. The key size can be adjusted according to the actual type of the die, which is not limited here. The preset structure parameters are imported into the control device by being pre-configured and designed by the staff, and the control device can obtain the preset structure parameters.

[0124] In step 802, actual structure parameters of the reference die are determined.

[0125] The actual structure parameters refer to the structure parameters of the constructed reference die, which are of the same type as the preset structure parameters. The actual structure parameters can be obtained in the following two ways: the first way, if the reference die is selected from the to-be-tested wafer, the corresponding actual structure parameters can be extracted from the gray scale image such as the scanning electron microscope image; the second way, if the reference die is a new die reconstructed, the actual structure parameters can be calculated by the preset structure parameters for reconstructing the reference die and the median of the gray scale. The above is only an example, and the present disclosure does not make any limitation on the specific determination form of the actual structure parameters, which can be selected according to actual conditions.

[0126] In step 803, structure differences between the preset structure parameters and the actual structure parameters are determined.

[0127] If the preset structure parameters are similar to the actual structure parameters, it means that the set reference die is more matched with each die in the to-be-tested wafer, and can be used as a reference for comparing with each die in the to-be-tested wafer, so as to realize the detection of defects. On the contrary, it means that the structure of the set reference die is greatly different from that of each die in the to-be-tested wafer, and the result of comparison as a reference die is less accurate. The present disclosure proposes the following solutions for the two comparison results:

[0128] In a first comparison result, if the structural difference is within the preset difference range, it means that the set reference wafer is matched with each wafer in the to-be-tested wafer, and the reference wafer is determined as a target reference wafer, and one-to-one comparison can be performed based on the target reference wafer and each wafer in the to-be-tested wafer, so as to realize detection of defects of each wafer.

[0129] In a second comparison result, if the structural difference is outside the preset difference range, a plurality of wafers in the to-be-tested wafer are reselected as new sample wafers, a new reference wafer is re-determined according to the new sample wafers, new actual structural parameters of the new reference wafer are determined, and then the structural difference between the preset structural parameters and the new actual structural parameters is re-determined. If the new structural difference is within the preset difference range, the new reference wafer is determined as the target reference wafer.

[0130] The embodiments of the present disclosure determine the reference wafer, and then perform comparison and judgment on the reference wafer based on the preset structural parameters of each wafer in the to-be-tested wafer, to judge the reliability of the determined reference wafer. In the case that the structural difference between the reference wafer and each wafer in the to-be-tested wafer is outside the preset difference range, a plurality of wafers in the to-be-tested wafer are reselected to determine a new reference wafer, until the structural difference between the two wafers is within the preset difference range. The reference wafer obtained in this way has higher reliability, and the detection effect of defect detection based on the reference wafer can be further improved.

[0131] In an optional embodiment of the present disclosure, the structural parameters at least include a critical dimension parameter and a position coordinate parameter. The critical dimension parameter is used to represent the specific shape of the wafer, and the position coordinate parameter is used to represent the specific position of the wafer. The structural parameters in the embodiments of the present disclosure at least include the critical dimension parameter and the position coordinate parameter. The difference between the determined reference wafer and each wafer in the to-be-tested wafer is judged based on the critical dimension parameter and the position coordinate parameter, which can improve the reliability of the target reference wafer obtained, and further improve the detection effect of defect detection based on the reference wafer.

[0132] In an optional embodiment of the present disclosure, the wafer is a chip, and the embodiments of the present disclosure are based on detection of each chip in the whole to-be-tested wafer, rather than defect detection of each storage unit in the chip. The difference between the to-be-tested wafer and each chip in the wafer can be detected, and the difference between each chip in the to-be-tested wafer can be accurately detected, which has a wider application and higher reliability.

[0133] Please refer to Figure 9 In an optional embodiment of the present disclosure, the step 304 of comparing the reference wafer with each wafer in the to-be-tested wafer one by one, and determining whether each wafer in the to-be-tested wafer has defects according to the comparison result, includes the following steps 901-902:

[0134] Step 901, respectively acquiring a reference gray scale map corresponding to a reference wafer and an actual gray scale map corresponding to each wafer in a wafer under test.

[0135] Step 902, comparing the reference gray scale map with the actual gray scale map, and determining whether each wafer in the wafer under test has a defect according to a comparison result.

[0136] The reference gray scale map and the actual gray scale map can be acquired by electron microscope scanning or any other optical detection method, and the embodiments of the present disclosure are not limited specifically and can be selected specifically according to actual conditions.

[0137] The embodiments of the present disclosure determine whether each wafer in the wafer under test has a defect based on the comparison result of the reference gray scale map and the actual gray scale map, are more intuitive, and have high efficiency and reliability.

[0138] In an optional embodiment of the present disclosure, the step 902 of comparing the reference gray scale map with the actual gray scale map includes the following steps:

[0139] Comparing the wafers at the same position points in the reference gray scale map and the actual gray scale map.

[0140] The same position in the embodiments of the present disclosure refers to the same position in each wafer, and the detection of defects based on the same position can improve the consistency of the difference comparison reference, thereby improving the reliability of the defect detection.

[0141] In an optional embodiment of the present disclosure, the step 902 of comparing the reference gray scale map with the actual gray scale map and determining whether each wafer in the wafer under test has a defect according to a comparison result includes the following steps:

[0142] The wafers at the same position points in the reference gray scale map and the actual gray scale map and having a gray scale value difference exceeding a preset threshold are determined as defective wafers.

[0143] If the gray scale values of the wafers at the same position are different, it means that the wafer and the reference wafer have a difference, and then the wafer having the difference is determined as a defective wafer. This comparison method is simple and fast and has high reliability.

[0144] Please refer to Figure 10 , a defect electron microscope scanning map and a corresponding data map detected by the defect detection method provided by the embodiments of the present disclosure. Among them, Figure 10 (a) is an electron microscope scanning map of a reference wafer, Figure 10 (b) is an electron microscope scanning map of a wafer under test, and from 10(c), a foreign matter area different from the reference wafer (a position corresponding to a white oval circle in 10(b)) can be compared.

[0145] Please refer to Fig. 11(a), Fig. 11(b), Fig. 11(c) respectively as Figure 10 (a), Figure 10 (b), Figure 10 (c) corresponding gray scale data graph. Fig. 11(a) is Figure 10 (a) corresponding gray scale data graph of the reference die, the horizontal coordinate is the pixel gray scale value, and the vertical coordinate is the pixel number of the gray scale value; Fig. 11(b) is Figure 10 (b) corresponding gray scale data graph of each die in the wafer to be measured, the horizontal coordinate is the pixel gray scale value, and the vertical coordinate is the pixel number of the gray scale value; Fig. 11(c) is Figure 10 (c) is the gray scale value difference data graph of the same position of the reference die and each die in the wafer to be measured, the horizontal coordinate is the pixel gray scale value difference, and the vertical coordinate is the corresponding number.

[0146] Please refer to Figure 12 In order to solve the above technical problems, another embodiment of the present disclosure provides a defect detection device 1200, comprising: a sample die selection module 1210, a determination module 1220, a reference die setting module 1230 and a comparison module 1240, wherein:

[0147] The sample die selection module 1210 is used for selecting a plurality of dies from the wafer to be measured as sample dies; wherein the wafer to be measured contains a plurality of dies;

[0148] The determination module 1220 is used for determining the median of the gray scale of the position points in the same area of the plurality of sample dies in units of pixels;

[0149] The reference die setting module 1230 is used for setting at least one reference die; wherein the gray scale value of the corresponding position points of the reference die is the median of the gray scale in units of pixels;

[0150] The comparison module 1240 is used for one-to-one comparison between the reference die and each die in the wafer to be measured, and determines whether there is a defect in each die in the wafer to be measured according to the comparison result.

[0151] In an optional embodiment of the present disclosure, the wafer to be measured contains a plurality of dies arranged in a matrix; and the sample die selection module 1210 is specifically used for selecting the dies in any column or any row of the wafer matrix as sample dies.

[0152] In an optional embodiment of the present disclosure, the determination module 1220 is specifically used for detecting the gray scale values of the position points in the same area of each sample die to obtain a plurality of first gray scale values; and calculating the median of the plurality of first gray scale values to obtain the median of the gray scale.

[0153] In an optional embodiment of the present disclosure, the determining module 1220 is specifically configured to detect the gray scale values of the same position points in each sample die to obtain a plurality of first gray scale values.

[0154] In an optional embodiment of the present disclosure, the reference die setting module 1230 is specifically configured to obtain preset structure parameters of each die in the wafer to be measured; and construct at least one reference die based on the preset structure parameters and the median gray scale value, wherein the gray scale value of the corresponding same position point of the reference die is the median gray scale value.

[0155] In an optional embodiment of the present disclosure, the reference die setting module 1230 is specifically configured to detect the gray scale values of the position points in the same region of each die in the wafer to be measured to obtain a plurality of second gray scale values; determine the difference between each second gray scale value and the median gray scale value respectively; and determine the die constructed based on the second gray scale value with the minimum difference as the reference die.

[0156] In an optional embodiment of the present disclosure, the reference die setting module 1230 is specifically configured to detect the gray scale values of the same position points in each die in the wafer to be measured to obtain a plurality of second gray scale values.

[0157] In an optional embodiment of the present disclosure, the reference die setting module 1230 is further configured to obtain preset structure parameters of each die in the wafer to be measured; determine the actual structure parameters of the reference die; determine the structure difference between the preset structure parameters and the actual structure parameters; and if the structure difference is within a preset difference range, determine the reference die as a target reference die.

[0158] In an optional embodiment of the present disclosure, the reference die setting module 1230 is further configured to, if the structure difference is outside the preset difference range, reselect a plurality of dies from the wafer to be measured as new sample dies; re-determine a new reference die according to the new sample dies; determine new actual structure parameters of the new reference die; and if the new structure difference between the new actual structure parameters and the preset structure parameters is within the preset difference range, determine the new reference die as the target reference die.

[0159] In an optional embodiment of the present disclosure, the structure parameters include critical dimension parameters and position coordinate parameters.

[0160] In an optional embodiment of the present disclosure, the die is a chip.

[0161] In an optional embodiment of the present disclosure, the comparison module 1240 is specifically configured to obtain a reference gray scale map corresponding to the reference die and an actual gray scale map corresponding to each die in the wafer to be measured respectively; compare the reference gray scale map with the actual gray scale map to determine whether each die in the wafer to be measured has a defect according to the comparison result.

[0162] In an optional embodiment of the present disclosure, the comparison module 1240 is specifically configured to compare the reference gray scale map with the actual gray scale map at the same position points in the same region.

[0163] In an optional embodiment of the present disclosure, the comparison module 1240 is specifically configured to determine a die as a defective die if the die is at the same position point in the reference gray scale map and the actual gray scale map and the difference in the gray scale values exceeds a preset threshold.

[0164] The defect detection apparatus 1200 provided in the embodiments of the present disclosure can realize automatic detection of the tiny defects with small differences in the dies of the wafer under test, greatly saving the labor cost, and improving the defect detection efficiency and reducing the cost. The other beneficial effects of the modules in the defect detection apparatus 1200 have been described in detail in the above embodiments, and will not be repeated here.

[0165] The example embodiments of the present disclosure also provide a computer readable storage medium, which can be implemented in the form of a program product, and includes program codes for causing an electronic device to perform the steps according to the various example embodiments of the present disclosure described in the above “example method” section of the present specification when the program product is run on the electronic device. In an embodiment, the program product can be implemented in the form of a portable compact disc read-only memory (CD-ROM) and includes program codes, and can be run on an electronic device, such as a personal computer. However, the program product of the present disclosure is not limited to this, and in the present document, the readable storage medium can be any tangible medium containing or storing a program, which can be used by or in conjunction with an instruction execution system, apparatus or device.

[0166] The program product can adopt any combination of one or more readable media. The readable medium can be a readable signal medium or a readable storage medium. The readable storage medium may, for example, be but is not limited to an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus or device, or any combination of the above. More specific examples (non-exhaustive list) of the readable storage medium include an electrical connection having one or more wires, a portable disc, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above.

[0167] A computer readable signal medium can include a propagated data signal with computer readable program code embodied therein, for example, in baseband or as part of a carrier wave. Such a propagated signal can take any of a variety of forms, including, but not limited to, electro-magnetic, optical, or any suitable combination thereof. A computer readable signal medium can be any computer readable medium that can be involved in

[0168] The code can be transmitted in any form in any medium, including, but not limited to, radio frequency (RF), wireless, wire line, optical, or any suitable combination of the foregoing.

[0169] The program code can be implemented in any of a variety of programming languages, including object-oriented programming languages such as Java, C++, and the like, and conventional procedural programming languages, such as the "C" programming language or similar programming languages. The program code can execute entirely on the user's computing device, partly on the user's computing device, as a stand-alone software package, partly on the user's computing device and partly on a remote computing device or entirely on the remote computing device or server. In the latter scenario, the remote computing device can be connected to the user's computing device through any type of network, including a local area network (LAN) or a wide area network (WAN), or the connection can be made to an external computing device, such as through the Internet using an Internet Service Provider. In an embodiment of the present disclosure, the program code stored in the computing device can implement any of the steps of the defect detection method as described above.

[0170] Referring to Figure 13 The exemplary embodiments of the present disclosure also provide an electronic device 1300, which can be a background server of an information platform. The following will refer to Figure 13 The electronic device 1300 will be described. It should be understood that Figure 13 The electronic device 1300 shown is merely an example, and should not bring any limitation to the functions and use range of the embodiments of the present disclosure.

[0171] As shown in Figure 13 The electronic device 1300 is in the form of a general computing device. The components of the electronic device 1300 can include, but are not limited to, at least one processing unit 1310, at least one storage unit 1320, and a bus 1330 connecting different system components, including the storage unit 1320 and the processing unit 1310.

[0172] The storage unit stores program codes which can be executed by the processing unit 1310, so that the processing unit 1310 performs the steps according to various exemplary embodiments of the present application described in the above "Exemplary Methods" section of the present specification. For example, the processing unit 1310 can perform the method steps shown in the above "Exemplary Methods" section, etc. Figure 3

[0173] The storage unit 1320 can include a volatile storage unit such as a random access memory (RAM) 1321 and / or a cache memory 1322, and further can include a non-volatile storage, or auxiliary storage unit 1323 such as a read only memory (ROM) 1323.

[0174] The storage unit 1320 can also include a program / utility 1324 having a set (at least one) of program modules 1325 that include, but are not limited to, an operating system, one or more application programs, other program modules, and program data, each or some combination thereof, which may

[0175] The bus 1330 can include a data bus, an address bus, and a control bus.

[0176] The electronic device 1300 can also communicate with one or more external devices 2000 such as a keyboard or pointing device, a Bluetooth device, etc. through Input / Output (I / O) interface(s) 1340. The electronic device 1300 can further include a network adapter 1350 to communicate with one or more networks, such as a local area network (LAN), a wide area network (WAN) and / or the Internet through a variety of connections including, but not limited to, standard telephone line, LAN, or wireless

[0177] In the embodiments of the present disclosure, the program codes stored in the electronic device can be executed to implement any of the steps in the above defect detection method.

[0178] It should be noted that although several modules or units of a device for action execution are mentioned in the above detailed description, such division is not mandatory. Indeed, according to the exemplary embodiments of the present disclosure, features and functions of two or more modules or units described above can be embodied in one module or unit. Conversely, features and functions of one module or unit described above can be further divided into a plurality of modules or units.

[0179] ​Those skilled in the art can understand that various aspects of the present disclosure can be implemented as a system, a method or a program product. Therefore, various aspects of the present disclosure can be embodied in a form of an entirely hardware embodiment, an entirely software embodiment (including firmware, microcode, etc.), or an embodiment combining hardware and software aspects in a manner that can all be generally referred to herein as a "circuit", "module" or "system". Other embodiments of the present disclosure will be readily apparent to those skilled in the art, and the general principles defined herein can be applied to other embodiments without departing from the scope of the present disclosure. The present disclosure is intended to encompass all such variations, uses or adaptations of the present disclosure and is intended to be protected by the claims hereafter. The specification and examples are illustrative only and not restrictive of the present disclosure, which is defined by the claims.

[0180] It should be understood that the present disclosure is not limited to the precise structures herein described and illustrated in the drawings and that various modifications and changes can be made therein without departing from the scope thereof. The scope of the present disclosure is limited only by the claims appended hereto.

Claims

1. A defect detection method characterized by, The method comprises the following steps: selecting a plurality of dies from a wafer to be tested as sample dies; wherein the wafer to be tested comprises a plurality of dies; determining the median gray scale value of the position points in the same area of the plurality of sample dies in units of pixels; setting at least one reference die, comprising: obtaining the preset structure parameters of each die in the wafer to be tested; constructing at least one reference die based on the preset structure parameters and the median gray scale value; wherein the preset structure parameters are the structure parameters of each die in the wafer to be tested designed in advance, and the structure parameters include critical dimension parameters and position coordinate parameters; the gray scale value of the corresponding same position points of the reference die in units of pixels is the median gray scale value; comparing the reference die with each die in the wafer to be tested one by one, and determining whether each die in the wafer to be tested has a defect according to the comparison result.

2. The defect detection method according to claim 1, characterized by, The wafer to be tested comprises a plurality of dies arranged in a matrix; The method of selecting a plurality of dies from a wafer to be tested as sample dies comprises: selecting the dies in any column or any row of the wafer matrix as the sample dies.

3. The defect detection method of claim 1, wherein The method of determining the median gray scale value of the position points in the same area of the plurality of sample dies comprises: detecting the gray scale values of the position points in the same area of each sample die to obtain a plurality of first gray scale values; calculating the median of the plurality of first gray scale values to obtain the median gray scale value.

4. The defect detection method according to claim 3, characterized by, The method of detecting the gray scale values of the position points in the same area of each sample die to obtain a plurality of first gray scale values comprises: detecting the gray scale values of each same position point in each sample die to obtain the plurality of first gray scale values.

5. The defect detection method according to any one of claims 1 to 4, characterized in that, After the step of setting at least one reference die, the method further comprises: obtaining the preset structure parameters of each die in the wafer to be tested; determining the actual structure parameters of the reference die, wherein the actual structure parameters are the structure parameters of the constructed reference die, and the structure parameters include critical dimension parameters and position coordinate parameters; determining the structure difference between the preset structure parameters and the actual structure parameters; if the structure difference is within a preset difference range, the reference die is determined as a target reference die.

6. The defect detection method of claim 5, wherein After the step of setting at least one reference die, the method further comprises: if the structure difference is outside the preset difference range, a plurality of dies are reselected from the wafer to be tested as new sample dies; a new reference die is determined according to the new sample dies; a new actual structure parameter of the new reference die is determined; if the new structure difference between the new actual structure parameter and the preset structure parameter is within the preset difference range, the new reference die is determined as the target reference die.

7. The defect detection method of claim 1, wherein The die is a chip.

8. The defect detection method of claim 1, wherein, The method of comparing the reference die with each die in the wafer to be tested one by one, and determining whether each die in the wafer to be tested has a defect according to the comparison result comprises: respectively obtaining a reference gray scale map corresponding to the reference die and an actual gray scale map corresponding to each die in the wafer to be tested; The reference gray scale map is compared with the actual gray scale map, and whether each die in the wafer under test has a defect is determined according to a comparison result.

9. The defect detection method of claim 8, wherein, The comparison of the reference gray scale map with the actual gray scale map comprises: The reference gray scale map is compared with a same position point in the actual gray scale map.

10. The defect detection method of claim 9, wherein The comparison of the reference gray scale map with the actual gray scale map comprises: The reference gray scale map is compared with a same position point in the actual gray scale map.

11. A defect detection apparatus characterized by comprising: The reference gray scale map is compared with a same position point in the actual gray scale map. Comprise: A sample die selection module is configured to select a plurality of dies from a wafer under test as sample dies, wherein the wafer under test comprises a plurality of dies; A determination module is configured to determine, in units of pixels, a median of gray scales of position points in a same region of the sample dies; A reference die setting module is configured to set at least one reference die, comprising: obtaining preset structure parameters of each die in the wafer under test; and constructing at least one reference die based on the preset structure parameters and the median of the gray scales; wherein the preset structure parameters are structure parameters of each die in the wafer under test designed in advance, the structure parameters comprise a critical dimension parameter and a position coordinate parameter; and in units of pixels, a gray scale value of a corresponding same position point of the reference die is the median of the gray scales; 12. A computer readable storage medium having stored thereon a computer program, characterized in that, A comparison module is configured to compare each die in the wafer under test with the reference die one by one, and determine whether each die in the wafer under test has a defect according to a comparison result.

13. An electronic device, comprising: The computer program is executed by the processor to implement the defect detection method of any one of claims 1 to 10. Comprise: A processor; And A memory for storing executable instructions of the processor; Wherein the processor is configured to implement the defect detection method of any one of claims 1 to 10 by executing the executable instructions.

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