Method, device and equipment for detecting mask pattern position accuracy

Abstract

The present application discloses a method, device and equipment for detecting the position accuracy of a mask pattern, and relates to the field of accuracy detection. The method comprises: selecting an initial pattern in an image display area; taking the center position of the initial pattern as the origin, stepping in the image display area along an exposure direction perpendicular to a photolithography machine, taking out a pattern identical to the initial pattern in the image display area every n selected intervals, until the stepping of the image display area is completed, obtaining multiple repeated patterns, and measuring the coordinate information of the center position of each repeated pattern to obtain a first coordinate set composed of the coordinate information of the multiple patterns; searching for a second coordinate set corresponding to the first coordinate set in the photolithography file of the mask; subtracting the coordinate information of the second coordinate set from the first coordinate set to obtain a deviation value of the pattern every n selected intervals; generating a data distribution diagram from the deviation value, and determining the detection result of the position accuracy of the mask pattern based on the data distribution state of the data distribution diagram.

Description

Technical Field

[0001] The present application relates to the field of detecting the position accuracy of a mask pattern, and more specifically, to a method, device and apparatus for detecting the position accuracy of a mask pattern. Background Art

[0002] Photomask, also known as photomask, chrome plate, photo mask, etc., is an important carrier for carrying graphic design and process technology. In the photolithography process, the mask is the carrier of the design pattern. The photolithography machine exposes the photoresist on the mask substrate in a line-by-line scanning manner, such as Figure 1 As shown, the design pattern is transferred to photoresist, then developed and etched, resulting in a pattern on a mask. The user then uses the mask as a pattern master for exposure, thus transferring the pattern to the silicon wafer. The mask is a critical component in the photolithography process, carrying the accuracy and integrity of the pattern data, which directly determines the yield rate of downstream products (such as display screens), and has a crucial impact.

[0003] The production of downstream products often requires a set of masks. For example, the production of a TFT LCD display requires 4-8 masks, while the production of an IC chip requires several to dozens of masks. These masks are superimposed and overlaid during production. When producing masks for flat panel displays, if the lithography equipment experiences transient positioning anomalies or the local flatness of the original mask substrate is abnormal, the mask may experience a sudden change in pattern position accuracy. This means that starting from a certain pattern position, all pattern positions will shift by tens to hundreds of nanometers. Because the pattern position offset is at the nanometer level, it is difficult for the human eye to detect. When this abnormal mask is overlaid with qualified masks from other layers, the patterns that should have been perfectly aligned will be misaligned with the patterns of other layers due to the sudden change in pattern position accuracy. This will cause banding mura on the product and reduce product yield.

[0004] Currently, before a mask leaves the factory, its total length in the X or Y direction of the two-dimensional plane is usually measured and compared with the design value to determine whether the mask's total length accuracy meets the requirements. The allowable tolerance for total length accuracy generally ranges from a few hundred nanometers to microns. Therefore, if a sudden change in the pattern position accuracy occurs locally on the mask, and the resulting position accuracy offset is within tens or hundreds of microns, it is difficult to detect such anomalies by measuring the total length of the mask or through manual visual inspection. Summary of the Invention

[0005] The purpose of this application is to provide a method, device and equipment for detecting the position accuracy of a mask pattern. This application solves the problem of being unable to effectively detect whether there is an abnormal mutation in the position accuracy of the mask pattern.

[0006] In a first aspect of the present application, a method for detecting the position accuracy of a mask pattern is provided, the method comprising:

[0007] Select an initial pattern of the image display area of ​​the mask;

[0008] Taking the center position of the initial pattern as the origin, stepping in the image display area along the exposure direction perpendicular to the lithography machine, taking out a pattern identical to the initial pattern in the image display area every n selected intervals until the stepping of the image display area is completed, obtaining multiple repeated patterns, and measuring the coordinate information of the center position of each repeated pattern to obtain a first coordinate set consisting of the coordinate information of the multiple patterns; wherein n is a positive integer, and the value of n is determined by the scanning bandwidth of the lithography machine and the size parameters of the image display area;

[0009] Obtaining a photolithography file of a mask, and searching the photolithography file for a second coordinate set corresponding to the coordinate information of the first coordinate set;

[0010] Subtracting the coordinate information of the second coordinate set from the coordinate information of the first coordinate set to obtain the deviation value of the graphic at every n selected intervals;

[0011] A data distribution graph is generated from the deviation value, and the detection result of the mask pattern position accuracy is determined based on the data distribution state of the data distribution graph.

[0012] In an implementation of the first aspect of the present application, an initial graphic of the image display area of ​​the mask is selected, specifically: a cross, square or L-shape at an edge corner of the image display area is selected as the initial graphic.

[0013] In an implementation of the first aspect of the present application, the photolithography file is a photolithography file used by a photolithography machine to make a mask.

[0014] In one implementation of the first aspect of the present application, a data distribution graph is generated by the deviation value, specifically: a horizontal and vertical coordinate system is constructed, and the data points in the horizontal and vertical coordinate system are determined based on the total number of graphics and the deviation value of the graphics at every n selected intervals. According to the order in which the graphics are selected in the image display area, the data points in the horizontal and vertical coordinate systems are connected in sequence to generate a data distribution graph.

[0015] In one implementation of the first aspect of the present application, the detection result of the mask plate graphic position accuracy is determined based on the data distribution status of the data distribution diagram, including: if it is detected that the absolute value of the deviation value of multiple consecutive data points in the data distribution diagram is greater than a threshold, then the detection result of the mask plate graphic position accuracy is abnormal; otherwise, the detection result of the mask plate graphic position accuracy is normal.

[0016] In an implementation of the first aspect of the present application, the method further includes:

[0017] Select m data points as a detection period, and determine the total number of detection periods in the image display area based on the length of the detection period and the total number of data points in the image display area; where m is a positive integer;

[0018] Calculate the average deviation value of each detection cycle, and calculate the difference between the average deviation values ​​of two adjacent detection cycles by combining the average deviation values ​​of each detection cycle;

[0019] The risk state of banded mura in the image display area of ​​the mask at the detection cycle is determined based on the range of the difference and the ratio of the selected pitch, wherein the selected pitch refers to the repetitive pitch between two adjacent sub-pixels.

[0020] In an implementation of the first aspect of the present application, the range of the ratio of the difference value to the selected spacing value includes a first sub-range, a second sub-range, a third sub-range, and a fourth sub-range;

[0021] If the ratio of the difference to the selected spacing is in the first sub-range, the risk status of the banding mura is the first level;

[0022] If the ratio of the difference to the selected spacing is in the second sub-range, the risk status of the band mura is the second level;

[0023] If the ratio of the difference to the selected spacing is in the third sub-range, the risk status of band mura is the third level;

[0024] If the ratio of the difference to the selected spacing is in the fourth sub-range, the risk status of band mura is the fourth level;

[0025] Among them, the risk status of the first level is greater than the risk status of the second level, the risk status of the second level is greater than the risk status of the third level, and the risk status of the third level is greater than the risk status of the fourth level.

[0026] In an implementation of the first aspect of the present application, the first sub-range is greater than a value obtained by multiplying the first proportion by the sub-pixel repetition pitch;

[0027] The second sub-range is greater than or equal to a value obtained by multiplying the second proportion by the sub-pixel repetition spacing, and less than a value obtained by multiplying the first proportion by the sub-pixel repetition spacing;

[0028] The third sub-range is greater than or equal to a value obtained by multiplying the third proportion by the sub-pixel repetition spacing, and less than a value obtained by multiplying the second proportion by the sub-pixel repetition spacing;

[0029] The fourth sub-range is smaller than a value obtained by multiplying the third ratio by the sub-pixel repetition pitch.

[0030] In a second aspect of the present application, a device for detecting the position accuracy of a mask pattern is provided, the device comprising:

[0031] An initial pattern selection module is used to select an initial pattern of the image display area of ​​the mask;

[0032] A first determination module is configured to use the center position of the initial pattern as an origin, step in an image display area along an exposure direction perpendicular to the lithography machine, and extract a pattern identical to the initial pattern from the image display area every n selected intervals until the stepping of the image display area is completed, thereby obtaining multiple repeated patterns, and measuring the coordinate information of the center position of each repeated pattern to obtain a first coordinate set consisting of the coordinate information of the multiple patterns; wherein n is a positive integer, and the value of n is determined by the scanning bandwidth of the lithography machine and the size parameters of the image display area;

[0033] A second determination module is configured to obtain a photolithography pattern of a mask and search the photolithography pattern for a second coordinate set corresponding to the coordinate information of the first coordinate set;

[0034] A position spacing determination module is used to obtain the deviation value of the graphic at every n selected spacings by subtracting the coordinate information of the second coordinate set from the coordinate information of the first coordinate set;

[0035] The accuracy detection module is used to generate a data distribution diagram based on the deviation value, and determine the detection result of the mask pattern position accuracy based on the data distribution state of the data distribution diagram.

[0036] The third aspect of the present application provides a device for detecting the position accuracy of a mask pattern, wherein the device comprises a processor, a memory, and a computer program stored on the memory and executable by the processor, wherein when the computer program is executed by the processor, the steps of a method for detecting the position accuracy of a mask pattern provided in the first aspect of the present application are implemented.

[0037] Compared with the prior art, this application has the following beneficial effects:

[0038] In a method for detecting the position accuracy of a mask pattern provided in the present application, an initial pattern that is convenient for measuring coordinates is first selected, and a pattern identical to the initial pattern is taken out from the image display area every n selection intervals until the stepping of the image display area is completed, thereby obtaining multiple repeated patterns, and measuring the coordinate information of the center position of each repeated pattern to obtain a first coordinate set composed of the coordinate information of multiple patterns. Then, in combination with the photolithography file of the mask, a second coordinate set corresponding to the coordinate information of the first coordinate set is found, and the coordinate information of the second coordinate set is subtracted from the coordinate information of the first coordinate set to obtain the deviation value between the pattern selected every n selection intervals and the standard pattern. Finally, a data distribution graph is generated from the deviation value of each pattern, and the detection result of the mask pattern position accuracy is determined based on the data distribution state of the data distribution graph. Therefore, the present application can promptly detect whether there is an abnormality in the mutation of the pattern position accuracy of the mask, thereby promptly identifying and intercepting the abnormal mask to prevent it from flowing out and causing a decrease in the yield of downstream products. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] The drawings described herein are used to provide a further understanding of the embodiments of the present application, constitute a part of the present application, and do not constitute a limitation of the embodiments of the present application. In the drawings:

[0040] Figure 1 Schematic diagram of exposing photoresist on a mask substrate provided by the prior art;

[0041] Figure 2 A flowchart of a method for detecting the position accuracy of a mask pattern provided in an embodiment of the present application;

[0042] Figure 3 A schematic diagram of the composition of the mask provided in an embodiment of the present application;

[0043] Figure 4 A schematic diagram of stepping along an exposure direction perpendicular to a lithography machine provided in an embodiment of the present application;

[0044] Figure 5 A schematic diagram of a data distribution diagram provided in an embodiment of the present application;

[0045] Figure 6 A block diagram of the principle of a device for detecting the position accuracy of a mask pattern provided in an embodiment of the present application. DETAILED DESCRIPTION

[0046] In order to make the objectives, technical solutions and advantages of this application more clear, the present application is further described in detail below in conjunction with examples and drawings. The schematic implementation methods of this application and their descriptions are only used to explain this application and are not intended to limit this application.

[0047] It should be noted that the terms "include" or "may include" used in various embodiments of the present application indicate the presence of the claimed function, operation or element, and do not limit the addition of one or more functions, operations or elements. In addition, as used in various embodiments of the present application, the terms "include", "have" and their cognates are only intended to indicate specific features, numbers, steps, operations, elements, components or combinations of the foregoing items, and should not be understood as first excluding the presence of one or more other features, numbers, steps, operations, elements, components or combinations of the foregoing items or the possibility of adding one or more features, numbers, steps, operations, elements, components or combinations of the foregoing items.

[0048] It should be understood that terms such as "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features indicated. Thus, a feature specified as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, "plurality" means two or more, unless otherwise specifically defined.

[0049] First, the technical terms used in this application are explained.

[0050] Mura refers to the phenomenon of uneven color and brightness between pixels in a display due to various reasons. This unevenness can cause various artifacts, affecting the display and making the viewing experience uncomfortable. Specifically, mura can be caused by issues with the high uniformity of display brightness, afterimages, limitations of uneven electric, flow, magnetic, and thermal fields in the device, or uneven crystallization. For example, in OLED displays, due to technical challenges in the manufacturing process, it can be difficult to achieve completely uniform pixel brightness and color.

[0051] Currently, the production of downstream products often requires a set of masks. For example, the production of a TFT LCD display requires four to eight masks, while the production of an IC chip requires several to dozens of masks. These masks are superimposed and overlaid during production. When producing flat panel display masks, if the lithography equipment experiences transient positioning anomalies or the local flatness of the original mask substrate is abnormal, the mask may experience a sudden change in pattern position accuracy. This means that starting from a certain pattern position, all pattern positions will shift by tens to hundreds of nanometers. Because the pattern position shift is at the nanometer level, it is difficult for the human eye to detect. When this abnormal mask is overlaid with a qualified mask from another layer, the pattern that should have been perfectly aligned will be misaligned with the patterns on other layers due to the sudden change in pattern position accuracy. This will cause banding mura on the product and reduce product yield.

[0052] Currently, before a mask leaves the factory, its total length in the X or Y direction of the two-dimensional plane is usually measured and compared with the design value to determine whether the mask's total length accuracy meets the requirements. The allowable tolerance for total length accuracy generally ranges from a few hundred nanometers to microns. Therefore, if a sudden change in the pattern position accuracy occurs locally on the mask, and the resulting position accuracy offset is within tens or hundreds of microns, it is difficult to detect such anomalies by measuring the total length of the mask or through manual visual inspection.

[0053] Therefore, in order to solve the problem of being unable to effectively detect abnormalities caused by sudden changes in the positional accuracy of a reticle pattern, the present application provides a method for detecting the positional accuracy of a reticle pattern. The method first selects an initial pattern that is convenient for coordinate measurement. Then, a pattern identical to the initial pattern is extracted from the image display area every n selection intervals until the image display area is stepped, thereby obtaining multiple repeated patterns. The coordinate information of the center position of each repeated pattern is measured to obtain a first coordinate set consisting of the coordinate information of the multiple patterns. Then, a second coordinate set corresponding to the coordinate information of the first coordinate set is found in conjunction with the lithography pattern of the reticle. The coordinate information of the second coordinate set is then subtracted from the coordinate information of the first coordinate set to obtain the deviation value between the pattern selected every n selection intervals and the standard pattern. Finally, a data distribution graph is generated from the deviation value of each pattern. The detection result of the positional accuracy of the reticle pattern is determined based on the data distribution status of the data distribution graph. Therefore, the present application can promptly detect whether there is an abnormality caused by sudden changes in the positional accuracy of the reticle pattern, thereby promptly identifying and intercepting the abnormal reticle to prevent it from being discharged and causing a decrease in the yield of downstream products.

[0054] The following is a detailed description of the specific implementation of the method provided in the embodiment of the present application with reference to the accompanying drawings. Figure 2 , Figure 2 A flow chart of a method for detecting the position accuracy of a mask pattern provided in an embodiment of the present application is shown as follows: Figure 2 As shown, the method includes:

[0055] 201, selecting an initial graphic of the image display area of ​​the mask.

[0056] In an embodiment, Figure 3 As shown, Figure 3 The main graphic area in the embodiment is the image display area of ​​the mask described in this embodiment. The so-called image display area is the area where the internal circuits are all composed of the same transistor design pattern repeatedly. Figure 3 The multiple small rectangles of uniform size in the image are responsible for turning the display sub-pixels on and off. The non-main graphic area refers to the external power supply area outside the image display area, such as the IC chip and leads. The patterns in this area are not regularly repeated and do not participate in image display. Therefore, they are not targeted for mura control.

[0057] For the initial graphic, in order to facilitate the measurement of the coordinates of the center position of the initial graphic, this embodiment selects a cross, square or L-shaped edge corner of the image display area as the initial graphic. Specifically, Figure 3 As shown, a cross-shaped figure (or other figure convenient for measuring coordinates) closest to the outermost single-particle figure of the main graphic area is selected, where the edge angle refers to any corner area of ​​the upper left corner, lower left corner, upper right corner, and lower right corner of the image display area.

[0058] 202. Taking the center position of the initial graphic as the origin, step in the image display area along the exposure direction perpendicular to the photolithography machine, and take out a graphic identical to the initial graphic in the image display area every n selected intervals until the stepping of the image display area is completed, thereby obtaining multiple repeated graphics, and measuring the coordinate information of the center position of each repeated graphic to obtain a first coordinate set consisting of the coordinate information of the multiple graphics; wherein n is a positive integer, and the value of n is determined by the scanning bandwidth of the photolithography machine and the size parameters of the image display area.

[0059] In this embodiment, the center of the initial pattern is used as the origin, meaning the starting point of the step is at the center of the initial pattern. By selecting the edge angle, for example, we can determine whether the stepping direction is left or right. Furthermore, as shown in Figure 4, the exposure direction refers to the direction of movement of the mask within the step of the lithography machine. The principle of movement is to decompose the main pattern area of ​​the entire reticle into multiple step paths. With each step perpendicular to the exposure direction, the platform automatically steps to the next step pattern. In other words, the exposure direction is the direction of movement of the lithography machine within the step path; the direction perpendicular to the exposure direction is the direction of the platform's stepping movement after a step is completed. The two are perpendicular to each other.

[0060] Specifically, during the stepping process, a graphic identical to the initial graphic is selected in the image display area every n selection intervals. For the selection interval, Figure 3 As shown, in the main graphics area, the horizontal length of a graphic plus the length of the gap between two graphics is the total length of the selected pitch. Therefore, for n selected pitches, this embodiment is determined by the scanning bandwidth of the lithography machine and the size parameters of the image display area. For example, n can be 1 or an integer greater than or equal to 2. When n is 1, this embodiment adopts a pitch-by-pitch selection method. When n is greater than or equal to 2, this embodiment adopts a segment-by-segment (integer multiples of pitch) selection method. After the entire image display area is stepped, a corresponding number of graphics are obtained. These graphics are numbered in sequence and then associated with the coordinate information of the measured center position of each graphic. It can be understood that the coordinate information refers to plane coordinate information, such as x and y. Combining the coordinate information and numbers of these graphics, a first coordinate set consisting of the coordinate information of the center positions of multiple graphics can be established and recorded in sequence as P0 (P0X; P0Y), P1 (P1X; P1Y), ..., Pb (PbX; PbY). Correspondingly, Pb in P0X, P1X, ..., PbX is the serial number of the selected graphic, and X and Y are the two-dimensional plane coordinate information of the corresponding graphic.

[0061] 203 , obtaining a photolithography pattern of a mask, and searching the photolithography pattern for a second coordinate set corresponding to the coordinate information of the first coordinate set.

[0062] In this embodiment, the photolithography pattern is a photolithography pattern of a mask along the exposure direction perpendicular to the photolithography machine. Since the selected patterns are all numbered and the number of selected spacings n is predetermined, a second coordinate set corresponding to the coordinate information of the first coordinate set can be found from the photolithography pattern. The coordinate information of the second coordinate set is the ideal position information of each pattern. For example, based on the photolithography pattern of the mask, the design coordinates corresponding to each point in the first coordinate set are found and recorded in sequence as D0 (D0X; D0Y), D1 (D1X; D1Y), ..., Db (DbX; DbY), which is the second coordinate set provided by this embodiment. Accordingly, Db in DX0, D1X, ..., DbX is the serial number of the design pattern.

[0063] 204 , subtracting the coordinate information of the second coordinate set from the coordinate information of the first coordinate set to obtain the deviation value of the graphic at every n selected intervals.

[0064] In this embodiment, the coordinate values ​​measured perpendicular to the exposure direction are subtracted from the coordinate values ​​of the corresponding points on the lithography design file in that direction to obtain the deviation value Rn of a single pattern selected every 3-5 pitches. In other words, Rn = DnX - PnX.

[0065] 205 , generating a data distribution graph based on the deviation value, and determining a detection result of the position accuracy of the mask pattern based on a data distribution state of the data distribution graph.

[0066] In some embodiments, a data distribution graph is generated by the position spacing of each graphic, specifically: a horizontal and vertical coordinate system is constructed, and the data points in the horizontal and vertical coordinate system are determined based on the total number of graphics and the deviation value of the graphics at every n selected spacings. According to the order in which the graphics are selected in the image display area, the data points in the horizontal and vertical coordinate systems are connected in sequence to generate a data distribution graph.

[0067] like Figure 5 As shown, the position spacing of these graphics is R0, R1, ..., Rn. In this embodiment, the data distribution diagram is made using Excel tools. It can be understood that other data processing tools can also be used. If the distribution of each continuous data point is random (such as Figure 5 ), it means the mask is qualified; if each data point appears as shown in the box on the left Figure 5 The jump situation shown in the large box on the right indicates that there is an abnormality in the graphic position accuracy of the mask at the jump point and the area behind it. When it is used in conjunction with masks of other qualified layers, a banded mura problem will appear on products such as displays.

[0068] In some embodiments, the detection result of the mask plate graphic position accuracy is determined based on the data distribution status of the data distribution diagram, including: if it is detected that the absolute value of the deviation value of multiple consecutive data points in the data distribution diagram is greater than a threshold, then the detection result of the mask plate graphic position accuracy is abnormal; otherwise, the detection result of the mask plate graphic position accuracy is normal.

[0069] Specifically, as an ideal situation, the position information of each pattern on the mask should be the same as the position information of each pattern on the mask after being lithographically processed by the photolithography machine. That is, the position spacing value calculated in step 104 should be zero, so that the display product composed of multiple mask plates superimposed on each other will not have mura problems. However, in the actual production process, there will definitely be deviations between the standard product and the actual product. This is limited by the process level and is unavoidable. Therefore, this embodiment determines whether there is an abnormality in the pattern position accuracy of the mask based on the relationship between the absolute value of each position spacing and a preset threshold value. For example, the threshold value range can be set to 300-350, for example Figure 5 The data distribution diagram shown is Figure 5 As shown in the box on the left, it can be seen that the absolute values ​​of the position spacing of each data point in the vertical axis direction are roughly in the range of 0 to 300, without excessive fluctuation. Therefore, the fluctuation of the position of the pattern is relatively reasonable, which means that the mask in this part is qualified. However, the absolute values ​​of the position spacing of the data points in the subsequent large boxes basically exceed 400, which does not meet the threshold value range. In other words, there is a large jump in the absolute values ​​of the data points in the two boxes before and after, indicating that the pattern position accuracy of the mask is abnormal at the jump point and the subsequent area. When used in combination with masks of other qualified layers, a banded mura problem will appear on the display product.

[0070] According to the embodiments of the method described in the above embodiments, it can be seen that the method provided by the embodiments of the present application solves the problem of being unable to effectively detect whether there is an abnormality such as a sudden change in pattern position accuracy on the mask.

[0071] In some embodiments, the method further includes: selecting m data points as a detection period, and determining the total number of detection periods in the image display area by combining the length of the detection period and the total number of data points in the image display area; wherein m is a positive integer; calculating the average deviation value of each detection period, and calculating the difference between the average deviation values ​​of two adjacent detection periods by combining the average deviation values ​​of each detection period; and determining the risk state of banded mura in the image display area of ​​the mask at the detection period based on the range of the difference and the ratio of the selected spacing; wherein the selected spacing refers to the repetitive spacing between two adjacent sub-pixels.

[0072] In this embodiment, m refers to the number of data points, or in other words, the number of data points in the image display area after the initial pattern array. Therefore, depending on the product design standards, the number of data points in the mask varies, ranging from hundreds to thousands. Because there are many different types of display products, each with different requirements for screen refinement, this embodiment further determines the risk level of mura in the mask. This allows for the selection of appropriate masks with abnormal pattern locations for different display products, thereby increasing the utilization rate of defective masks.

[0073] Because the sub-pixel repeat pitch varies for each reticle pattern design, the pitch range provided in this embodiment needs to be adjusted based on the actual reticle. As an example, the sub-pixel repeat pitch provided in this embodiment is 42 microns, but because the pattern spacing is measured in nanometers, the sub-pixel repeat pitch is 42,000 nanometers.

[0074] In view of the current technological level, this embodiment sets four sub-ranges as the evaluation intervals for each risk level. Of course, it can also include five, six, or even more sub-ranges as the judgment criteria for abnormal risk level. In some embodiments, the range of the ratio of the difference value to the selected spacing value includes a first sub-range, a second sub-range, a third sub-range, and a fourth sub-range;

[0075] If the ratio of the difference to the selected spacing is in the first sub-range, the risk status of the banding mura is the first level;

[0076] If the ratio of the difference to the selected spacing is in the second sub-range, the risk status of the band mura is the second level;

[0077] If the ratio of the difference to the selected spacing is in the third sub-range, the risk status of band mura is the third level;

[0078] If the ratio of the difference to the selected spacing is in the fourth sub-range, the risk status of band mura is level 4;

[0079] Among them, the risk status of the first level is greater than the risk status of the second level, the risk status of the second level is greater than the risk status of the third level, and the risk status of the third level is greater than the risk status of the fourth level.

[0080] It can be understood that the first level is high risk, the second level is medium risk, the third level is low risk, and the fourth level is no risk.

[0081] In one embodiment, the first sub-range is greater than a value obtained by multiplying the first proportion by the sub-pixel repetition pitch;

[0082] The second sub-range is greater than or equal to a value obtained by multiplying the second proportion by the sub-pixel repetition spacing, and less than a value obtained by multiplying the first proportion by the sub-pixel repetition spacing;

[0083] The third sub-range is greater than or equal to a value obtained by multiplying the third proportion by the sub-pixel repetition spacing, and less than a value obtained by multiplying the second proportion by the sub-pixel repetition spacing;

[0084] The fourth sub-range is smaller than a value obtained by multiplying the third ratio by the sub-pixel repetition pitch.

[0085] In this embodiment, with respect to the current mask process level, as an exemplary implementation scheme, this embodiment provides a first ratio of 1%, a second ratio of 0.5%, and a third ratio of 0.2%. Of course, in addition to the ratio values ​​designed in this embodiment, other ratios can also be designed based on the accuracy requirements of the current display screen.

[0086] Please refer to Figure 6 , Figure 6 A block diagram of the principle of a device for detecting the position accuracy of a mask pattern provided in an embodiment of the present application, such as Figure 6 As shown:

[0087] An initial pattern selection module 610 is used to select an initial pattern of the image display area of ​​the mask;

[0088] A first determination module 620 is configured to use the center position of the initial pattern as an origin, step in the image display area along an exposure direction perpendicular to the lithography machine, and extract a pattern identical to the initial pattern from the image display area every n selected intervals until the stepping of the image display area is completed, thereby obtaining multiple repeated patterns, and measuring the coordinate information of the center position of each repeated pattern to obtain a first coordinate set consisting of the coordinate information of the multiple patterns; wherein n is a positive integer, and the value of n is determined by the scanning bandwidth of the lithography machine and the size parameters of the image display area;

[0089] The second determination module 630 is configured to obtain a photolithography pattern of a mask and search the photolithography pattern for a second coordinate set corresponding to the coordinate information of the first coordinate set;

[0090] A position spacing determination module 640 is configured to obtain a deviation value of the graphic at every n selected spacings by subtracting the coordinate information of the second coordinate set from the coordinate information of the first coordinate set;

[0091] The accuracy detection module 650 is used to generate a data distribution diagram based on the deviation value, and determine the detection result of the position accuracy of the mask pattern according to the data distribution state of the data distribution diagram.

[0092] It can be seen that in an apparatus for detecting the position accuracy of a mask pattern provided in an embodiment of the present application, an initial pattern that is convenient for measuring coordinates is first selected, and a pattern identical to the initial pattern is taken out from the image display area every n selection intervals until the stepping of the image display area is completed, thereby obtaining multiple repeated patterns, and measuring the coordinate information of the center position of each repeated pattern to obtain a first coordinate set composed of the coordinate information of multiple patterns. Then, in combination with the lithography pattern of the mask, a second coordinate set corresponding to the coordinate information of the first coordinate set is found, and then the coordinate information of the second coordinate set is subtracted from the coordinate information of the first coordinate set to obtain the deviation value between the pattern selected every n selection intervals and the standard pattern. Finally, a data distribution graph is generated from the deviation value of each pattern, and the detection result of the mask pattern position accuracy is determined based on the data distribution state of the data distribution graph. Therefore, the present application can promptly detect whether there is an abnormality in the mutation of the pattern position accuracy of the mask, thereby promptly identifying and intercepting the abnormal mask to prevent it from flowing out and causing a decrease in the yield of downstream products.

[0093] The present application also provides an apparatus for detecting the position accuracy of a mask pattern, the apparatus comprising a processor, a memory, a communication interface, and at least one communication bus for connecting the processor, the memory, and the communication interface. The memory includes, but is not limited to, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (PROM), or compact disc read-only memory (CD-ROM), and is used for related instructions and data.

[0094] The communication interface is used to receive and send data. The processor may be one or more CPUs. In the case where the processor is a CPU, the CPU may be a single-core CPU or a multi-core CPU. The processor in the device for detecting the position accuracy of the mask pattern is used to read one or more programs stored in the memory and perform the following operations: selecting an initial pattern in the image display area of ​​the mask; taking the center position of the initial pattern as the origin, stepping in the image display area along the exposure direction perpendicular to the photolithography machine, taking out a pattern identical to the initial pattern in the image display area every n selection intervals, until the stepping of the image display area is completed, obtaining multiple repeated patterns, and measuring the coordinate information of the center position of each repeated pattern to obtain a first coordinate set consisting of the coordinate information of the multiple patterns; wherein n is a positive integer, and the value of n is determined by the scanning bandwidth of the photolithography machine and the size parameters of the image display area; obtaining the photolithography file of the mask, and searching for a second coordinate set corresponding to the coordinate information of the first coordinate set in the photolithography file; subtracting the coordinate information of the second coordinate set from the coordinate information of the first coordinate set to obtain the deviation value of the pattern every n selection intervals; generating a data distribution diagram based on the deviation value, and determining the detection result of the position accuracy of the mask pattern according to the data distribution state of the data distribution diagram.

[0095] It should be noted that the specific implementation of each operation can be as described above. Figure 1 The corresponding description of the method embodiment shown, the device for detecting the position accuracy of the mask pattern can be used to execute a method for detecting the position accuracy of the mask pattern in the above method embodiment of the present application, which will not be described in detail here.

[0096] In an embodiment of the present disclosure, a computer-readable storage medium is provided. The computer-readable storage medium is a memory device in a computer device, used to store programs and data. It is understood that the computer-readable storage medium herein may include both built-in storage media in the computer device and, of course, extended storage media supported by the computer device. The computer-readable storage medium provides storage space, which stores the terminal's operating system. Furthermore, the storage space also stores one or more instructions suitable for being loaded and executed by a processor. These instructions may be one or more computer programs (including program code). It should be noted that the computer-readable storage medium herein may be a high-speed RAM memory or a non-volatile memory, such as at least one disk drive. The processor may load and execute the one or more instructions stored in the computer-readable storage medium to implement the corresponding steps of the device method for detecting the position accuracy of a mask pattern described in the above-mentioned embodiment. Those skilled in the art will appreciate that embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware. Furthermore, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program codes.

[0097] The specific implementation methods described above further illustrate the purpose, technical solutions and beneficial effects of this application. It should be understood that the above description is only the specific implementation methods of this application and is not intended to limit the scope of protection of this application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of this application should be included in the scope of protection of this application.

Claims

1. A method for detecting the position accuracy of a mask pattern, characterized in that: Methods include: Select an initial pattern of the image display area of ​​the mask; Taking the center position of the initial pattern as the origin, stepping in the image display area along the exposure direction perpendicular to the lithography machine, taking out a pattern identical to the initial pattern in the image display area every n selected intervals until the stepping of the image display area is completed, obtaining multiple repeated patterns, and measuring the coordinate information of the center position of each repeated pattern to obtain a first coordinate set consisting of the coordinate information of the multiple patterns; wherein n is a positive integer, and the value of n is determined by the scanning bandwidth of the lithography machine and the size parameters of the image display area; Obtaining a photolithography file of a mask, and searching the photolithography file for a second coordinate set corresponding to the coordinate information of the first coordinate set; Subtracting the coordinate information of the second coordinate set from the coordinate information of the first coordinate set to obtain the deviation value of the graphic at every n selected intervals; Generate a data distribution graph based on the deviation value, and determine the detection result of the mask pattern position accuracy based on the data distribution state of the data distribution graph; The method further comprises: Select m data points as a detection period, and determine the total number of detection periods in the image display area based on the length of the detection period and the total number of data points in the image display area; where m is a positive integer; Calculate the average deviation value of each detection cycle, and calculate the difference between the average deviation values ​​of two adjacent detection cycles by combining the average deviation values ​​of each detection cycle; The risk state of banded mura in the image display area of ​​the mask at the detection cycle is determined based on the range of the difference and the ratio of the selected pitch, wherein the selected pitch refers to the repetitive pitch between two adjacent sub-pixels.

2. The method according to claim 1, characterized in that An initial pattern of the image display area of ​​the mask is selected, specifically: a cross, a square or an L-shape at an edge corner of the image display area is selected as the initial pattern.

3. The method according to claim 1, characterized in that The photolithography file is a photolithography file used by a photolithography machine to make a mask.

4. The method according to claim 1, wherein The data distribution graph is generated by the deviation value, specifically: constructing a horizontal and vertical coordinate system, combining the total number of graphics and the deviation value of the graphics selected every n intervals, determining the data points in the horizontal and vertical coordinate system, and connecting the data points in the horizontal and vertical coordinate system in sequence according to the order in which the graphics are selected in the image display area to generate a data distribution graph.

5. The method according to claim 1, characterized in that The detection result of the mask pattern position accuracy is determined based on the data distribution status of the data distribution diagram, including: if it is detected that the absolute value of the deviation value of multiple consecutive data points in the data distribution diagram is greater than the threshold, then the detection result of the mask pattern position accuracy is abnormal; otherwise, the detection result of the mask pattern position accuracy is normal.

6. The method according to claim 1, characterized in that The range of the difference value and the selected spacing ratio includes a first sub-range, a second sub-range, a third sub-range and a fourth sub-range; If the ratio of the difference to the selected spacing is in the first sub-range, the risk status of the banding mura is the first level; If the ratio of the difference to the selected spacing is in the second sub-range, the risk status of the band mura is the second level; If the ratio of the difference to the selected spacing is in the third sub-range, the risk status of band mura is the third level; If the ratio of the difference to the selected spacing is in the fourth sub-range, the risk status of band mura is the fourth level; Among them, the risk status of the first level is greater than the risk status of the second level, the risk status of the second level is greater than the risk status of the third level, and the risk status of the third level is greater than the risk status of the fourth level.

7. The method according to claim 6, characterized in that The first sub-range is greater than a value obtained by multiplying the first proportion by the sub-pixel repetition interval; The second sub-range is greater than or equal to a value obtained by multiplying the second proportion by the sub-pixel repetition spacing, and less than a value obtained by multiplying the first proportion by the sub-pixel repetition spacing; The third sub-range is greater than or equal to a value obtained by multiplying the third proportion by the sub-pixel repetition spacing, and less than a value obtained by multiplying the second proportion by the sub-pixel repetition spacing; The fourth sub-range is smaller than a value obtained by multiplying the third ratio by the sub-pixel repetition pitch.

8. A device for detecting the position accuracy of a mask pattern, characterized in that: The device includes: An initial pattern selection module is used to select an initial pattern of the image display area of ​​the mask; A first determination module is configured to use the center position of the initial pattern as an origin, step in an image display area along an exposure direction perpendicular to the lithography machine, and extract a pattern identical to the initial pattern from the image display area every n selected intervals until the stepping of the image display area is completed, thereby obtaining multiple repeated patterns, and measuring the coordinate information of the center position of each repeated pattern to obtain a first coordinate set consisting of the coordinate information of the multiple patterns; wherein n is a positive integer, and the value of n is determined by the scanning bandwidth of the lithography machine and the size parameters of the image display area; A second determining module is configured to obtain a photolithography pattern of a mask and search the photolithography pattern for a second coordinate set corresponding to the coordinate information of the first coordinate set; A position spacing determination module is used to obtain the deviation value of the graphic at every n selected spacings by subtracting the coordinate information of the second coordinate set from the coordinate information of the first coordinate set; The accuracy detection module is used to generate a data distribution map based on the deviation value, and determine the detection result of the mask pattern position accuracy based on the data distribution state of the data distribution map; The device further comprises: Select m data points as a detection period, and determine the total number of detection periods in the image display area based on the length of the detection period and the total number of data points in the image display area; where m is a positive integer; Calculate the average deviation value of each detection cycle, and calculate the difference between the average deviation values ​​of two adjacent detection cycles by combining the average deviation values ​​of each detection cycle; The risk state of banded mura in the image display area of ​​the mask at the detection cycle is determined based on the range of the difference and the ratio of the selected pitch, wherein the selected pitch refers to the repetitive pitch between two adjacent sub-pixels.

9. A device for detecting the position accuracy of a mask pattern, characterized in that: The device for detecting the position accuracy of a mask pattern includes a processor, a memory, and a computer program stored in the memory and executable by the processor, wherein when the computer program is executed by the processor, the steps of a method for detecting the position accuracy of a mask pattern as described in any one of claims 1 to 7 are implemented.

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