Calibration layout and calibration method for photomask cleaning process parameters

Abstract

The invention discloses a calibration layout and a calibration method for photomask cleaning process parameters. The calibration layout comprises a photomask substrate and at least one type of SRAF graph structure arranged on the photomask substrate. Wherein a plurality of SRAF graph structures of the same type are set according to different line width parameters; a plurality of SRAF graph structures with the same type and the same line width parameter are set according to different spacing parameters; a plurality of SRAF graph structures with the same type and the same line width parameter are set according to different line length parameters; a plurality of SRAF pattern structures with the same type, the same line width parameter, the same spacing parameter and the same line length parameter are arranged at different positions on the photomask substrate. The calibration layout can provide accurate and reliable data basis for the cleaning process of the photomask with the SRAF graph, and the photomask with the SRAF graph is prevented from being damaged in the cleaning process to a great extent.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of semiconductor technology, in particular to a photomask cleaning process parameter calibration layout and calibration method. BACKGROUND

[0002] Sub-Resolution Assist Feature (SRAF) is a kind of auxiliary structure pattern with size smaller than the resolution limit of the lithography system, which is added around the main pattern of the photomask, and plays a crucial role in improving the lithography precision by adjusting the local light intensity distribution of the photomask exposure and compensating the optical proximity effect.

[0003] However, the fine line width in the sub-resolution assist feature is very small, and it is easy to be damaged in the cleaning process, causing peeling, as shown in Figure 1 , as shown in Figure 1 , the damaged and undamaged structure of the fine line SRAF pattern structure is shown; the damaged SRAF pattern will distort the pattern after wafer exposure, resulting in reduced wafer yield. Therefore, before cleaning the photomask with sub-resolution assist feature, how to realize the reasonable setting of the cleaning parameters of the cleaning machine, and avoid the pattern damage of the cleaned photomask, is of great significance for the application of photomask containing sub-resolution assist feature. SUMMARY

[0004] The purpose of the present application is to provide a photomask cleaning process parameter calibration layout and calibration method, which can realize the calibration of cleaning process parameters according to SRAF pattern structures of different sizes, provide reliable data basis for photomask cleaning with SRAF pattern, and effectively avoid the cleaning damage of SRAF pattern.

[0005] To solve the above technical problems, the present application provides a photomask cleaning process parameter calibration layout, comprising a photomask substrate, and at least one type of SRAF pattern structure arranged on the photomask substrate;

[0006] Among them, for the same type of SRAF pattern structure, a plurality of SRAF pattern structures are arranged according to different line width parameters;

[0007] For the same type and same line width parameter of the SRAF pattern structure, a plurality of SRAF pattern structures are arranged according to different pitch parameters;

[0008] For the same type and same line width parameter of the SRAF pattern structure, a plurality of SRAF pattern structures are arranged according to different line length parameters;

[0009] For the same type, same line width parameter, same pitch parameter and same line length parameter of the SRAF pattern structure, a plurality of SRAF pattern structures are arranged at different positions on the photomask substrate.

[0010] In an alternative embodiment of the present application, the mask substrate is divided into at least two first-level regions uniformly, and each of the first-level regions has the same layout;

[0011] In each of the first-level regions, at least three second-level regions are divided uniformly along the longitudinal direction, and each of the second-level regions has the same layout;

[0012] In each of the second-level regions, at least nine third-level regions are divided uniformly along the longitudinal direction; the line width parameters of the SRAF pattern structures arranged in the same third-level region are all the same, and the line width parameters of the SRAF pattern structures arranged in different third-level regions in the same second-level region are all different;

[0013] In each of the third-level regions, a plurality of block units are divided uniformly along the transverse direction, and the layouts of different block units in the same third-level region are the same;

[0014] The SRAF pattern structures of different types, different pitch parameters and different line length parameters are arranged in the same block unit.

[0015] In an alternative embodiment of the present application, the SRAF pattern structure at least includes any one of dense SRAF structure, single-side main pattern SRAF structure, intermediate main pattern SRAF structure, short line dense SRAF structure, single-side main pattern short line SRAF structure;

[0016] The dense SRAF structure includes a plurality of first long line structures arranged in parallel and at equal intervals and having the same line length;

[0017] The single-side main pattern SRAF structure includes a main pattern structure and a plurality of long line structures arranged in parallel and at equal intervals on one side of the main pattern structure and having the same line length parameter;

[0018] The intermediate main pattern SRAF structure includes a plurality of long line structures arranged in parallel and at equal intervals and having the same line length parameter, and two main pattern structures arranged on both sides of each of the long line structures;

[0019] The short line dense SRAF structure includes a plurality of short line structures arranged in an array and having the same line length parameter;

[0020] The single-side main pattern short line SRAF structure includes a main pattern structure and a plurality of short line structures arranged in an array on one side of the main pattern structure and having the same line length parameter;

[0021] In the same SRAF pattern structure, the line width parameters are all the same; and in the same SRAF pattern structure, the pitch parameters are all integer multiples of the line width parameters.

[0022] In an alternative embodiment of the present application, the line width parameter of the SRAF pattern structure is set between 10 nm and 110 nm.

[0023] The pitch parameter of the SRAF pattern structure is set between 60 nm and 200 nm.

[0024] The line length parameter of the long line structure in the SRAF pattern structure is set between 1 um and 10 um, and the line length parameter of the short line structure is set between 10 nm and 1 um.

[0025] In an alternative embodiment of the present application, the SRAF pattern structure is any one of a pure chromium film layer structure, a chromium oxide film layer structure, a chromium nitride film layer structure, a chromium oxynitride film layer structure, a molybdenum silicon nitride film layer structure, a molybdenum silicon oxynitride film layer structure, a tantalum nitride film layer structure, a boron tantalum nitride film layer structure, and a silicon nitride film layer structure.

[0026] In an alternative embodiment of the present application, the thickness parameter of the SRAF pattern structure is the same and is set between 10 nm and 120 nm.

[0027] A calibration method of photomask cleaning process parameters, applied to the calibration pattern of photomask cleaning process parameters according to any one of the above; the calibration method comprises:

[0028] Cleaning the calibration pattern according to different cleaning process parameters;

[0029] Performing laser testing on the cleaned calibration pattern to obtain a test image of each SRAF pattern structure on the cleaned calibration pattern;

[0030] Comparing the test images of the same SRAF pattern structure at different positions on the calibration pattern to obtain a size parameter of the SRAF pattern structure corresponding to the existence of cleaning damage corresponding to each type of SRAF pattern structure; the size parameter includes a line width parameter, a pitch parameter, and a line length parameter;

[0031] According to the size parameter of the SRAF pattern structure corresponding to the existence of cleaning damage, determining the calibration cleaning process parameter corresponding to the non-damage cleaning of different types of SRAF pattern structures.

[0032] In an alternative embodiment of the present application, before cleaning the calibration pattern according to different cleaning process parameters, the method further comprises:

[0033] Performing prior laser testing on the calibration pattern to obtain a prior test image;

[0034] Accordingly, the process of comparing the test images corresponding to different primary regions in the same calibration map to determine the calibration cleaning process parameters includes:

[0035] By comparing the prior test image and the test image of the same first-level region in the same calibration pattern, and by comparing the test images corresponding to different first-level regions in the same calibration pattern, the type and size parameters of the SRAF graphic structure that actually caused the damage by the cleaning process parameters are obtained, and the calibration cleaning process parameters for no damage corresponding to each different SRAF graphic structure are determined.

[0036] In an optional embodiment of this application, the method for calibrating the coating process parameters further includes:

[0037] The calibration pattern that obtains the same calibration cleaning process parameters is used as the inspection calibration pattern;

[0038] According to the set time cycle, the calibration cleaning process parameters obtained from the previous calibration are used to clean the test calibration pattern in order to check whether the current calibration cleaning process parameters are accurate. If not, the cleaning machine is subjected to aging and damage detection for confirmation.

[0039] In an optional embodiment of this application, the method for calibrating the coating process parameters further includes:

[0040] Multiple calibration patterns with the same SRAF pattern structure are prepared in advance according to different coating processes;

[0041] The calibration patterns are cleaned using the same cleaning process parameters to determine the undamaged linewidth parameters of the undamaged SRAF image structure in each calibration pattern, so as to calibrate the adhesion of different coating processes.

[0042] The present invention provides a calibration layout and calibration method for photomask cleaning process parameters. The calibration layout includes a photomask substrate and at least one type of SRAF pattern structure disposed on the photomask substrate. Specifically, multiple SRAF pattern structures of the same type are provided with different linewidth parameters; multiple SRAF pattern structures of the same type and linewidth parameters are provided with different spacing parameters; multiple SRAF pattern structures of the same type and linewidth parameters are provided with different line length parameters; and multiple SRAF pattern structures of the same type, linewidth parameters, spacing parameters, and line length parameters are provided at different positions on the photomask substrate.

[0043] In the present application, SRAF pattern structures of multiple different structure types are formed on the same mask substrate, and multiple SRAF pattern structures with different size parameters such as line width parameter, line length parameter and pitch parameter are provided for the same type of SRAF pattern structure, and multiple SRAF pattern structures of the same type are provided at multiple different positions on the mask substrate, thereby simulating SRAF patterns of different size parameters and different position layouts in a real mask; thereby the calibration pattern is cleaned under various different cleaning process parameters of the cleaning machine, based on the damage of the SRAF pattern structure in the calibration pattern, the corresponding cleaning process parameters of the cleaning machine when cleaning SRAF pattern structures of various different size parameters are calibrated, and accurate and reliable data basis is provided for cleaning of the mask structure with SRAF pattern, which greatly avoids damage of the mask with SRAF pattern in the cleaning process, and is conducive to ensuring the precision of semiconductor lithography exposure. BRIEF DESCRIPTION OF DRAWINGS

[0044] In order to more clearly illustrate the technical solutions of the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0045] Figure 1 It is a schematic diagram of a local structure of a mask;

[0046] Figure 2 It is a schematic diagram of the overall structure of the calibration pattern of the mask cleaning process parameters provided by the embodiment of the present application;

[0047] Figure 3 It is a schematic diagram of the specific structure of the calibration pattern of the mask cleaning process parameters provided by the embodiment of the present application;

[0048] Figure 4 It is a schematic diagram of a local area provided with dense SRAF structure on the calibration pattern provided by the embodiment of the present application;

[0049] Figure 5 It is a schematic diagram of the cross section along Figure 4 A-A in the figure;

[0050] Figure 6 It is a schematic diagram of a local area provided with single-sided main pattern SRAF structure on the calibration pattern provided by the embodiment of the present application;

[0051] Figure 7 It is a schematic diagram of the cross section along Figure 6 B-B in the figure;

[0052] Figure 8 A schematic diagram of a local area with a dense SRAF structure on a calibration layout provided in an embodiment of this application;

[0053] Figure 9 For along Figure 8 A cross-sectional view of CC.

[0054] Figure 10 A schematic diagram of a local area with a dense short-line SRAF structure on the calibration layout provided in this application embodiment;

[0055] Figure 11 For along Figure 10 A cross-sectional schematic diagram of DD;

[0056] Figure 12 A schematic diagram of a local area with a single-sided main graphic short line SRAF structure on the calibration layout provided in this application embodiment;

[0057] Figure 13 For along Figure 12 A cross-sectional schematic diagram of the EE;

[0058] Figure 14 This is a schematic diagram comparing different spacing parameters of a dense SRAF structure provided in an embodiment of this application;

[0059] Figure 15 A schematic diagram comparing different spacing parameters of the short-line dense SRAF structure provided in the embodiments of this application;

[0060] Figure 16 This is a schematic flowchart illustrating the calibration method for photomask cleaning process parameters provided in the embodiments of this application. Detailed Implementation

[0061] The core of this invention is to provide a calibration layout and calibration method for photomask cleaning process parameters, which can realize the calibration of cleaning process parameters for SRAF patterns with different line widths in the photomask, and provide reliable data for cleaning photomasks with SRAF patterns.

[0062] To enable those skilled in the art to better understand the present invention, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. Obviously, the described embodiments are merely some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0063] like Figure 2 and Figure 3 As shown in a specific embodiment of this application, the calibration layout of the photomask cleaning process parameters may include:

[0064] a mask substrate, and at least one type of SRAF pattern structure arranged on the mask substrate;

[0065] wherein for the same type of SRAF pattern structure, a plurality are arranged according to different line width parameters;

[0066] for the same type of SRAF pattern structure with the same line width parameter, a plurality are arranged according to different pitch parameters;

[0067] for the same type of SRAF pattern structure with the same line width parameter, a plurality are arranged according to different line length parameters;

[0068] for the same type of SRAF pattern structure with the same line width parameter, the same pitch parameter and the same line length parameter, a plurality are arranged at different positions on the mask substrate.

[0069] As shown in FIG. 1, the calibration mask of the embodiment includes a mask substrate 1 and a plurality of SRAF pattern structures 20 arranged on the mask substrate 1. The SRAF pattern structures 20 are arranged on the mask substrate 1 in different types, different line width parameters, different pitch parameters and different line length parameters. Figure 2 As shown in FIG. 1, the calibration mask of the embodiment includes a mask substrate 1 and a plurality of SRAF pattern structures 20 arranged on the mask substrate 1. The SRAF pattern structures 20 are arranged on the mask substrate 1 in different types, different line width parameters, different pitch parameters and different line length parameters.

[0070] It can be understood that the SRAF pattern structure 20 is mainly composed of rectangular bars as structural units, wherein the line width parameter is the short side dimension of a single structural unit, the line length parameter is the long side dimension of a single structural unit, and the pitch parameter is the gap dimension between adjacent two structural units.

[0071] On this basis, for the same type of SRAF pattern structure 20 with the same line width parameter, the same pitch parameter and the same line length parameter, a plurality are arranged at different positions on the mask substrate.

[0072] It can be seen that the calibration mask in the embodiment fully simulates the SRAF pattern structure 20 of different structure types, different line widths, different pitches, different line lengths and even different positions on the real mask, so that the calibration mask is used as a test template, different cleaning process parameters are used for cleaning, and the requirements of the SRAF pattern structure 20 of different size parameters and arrangement positions for the cleaning process parameters can be fully and comprehensively obtained, thereby providing a reliable reference basis for cleaning of different mask with SRAF pattern.

[0073] In an optional embodiment of the present application, the calibration mask further includes a positioning mark structure 10 arranged at the corner edge position of the mask substrate 1.

[0074] Based on this, in an optional embodiment of this application, the calibration layout may further include:

[0075] At least two primary regions 11 are uniformly divided on the photomask substrate 1, and the layout of each primary region 11 is the same.

[0076] In each primary region 11, at least three secondary regions 12 are evenly divided along the longitudinal direction, and the layout of each secondary region 12 is the same.

[0077] In each secondary region 12, at least nine tertiary regions 13 are evenly divided along the longitudinal direction; the line width parameters of the SRAF graphic structures 20 set in the same tertiary region 13 are all the same, and the line width parameters of the SRAF graphic structures 20 set in different tertiary regions 13 in the same secondary region 12 are different.

[0078] In each third-level region 13, a set number of block units are evenly divided along the horizontal direction, and the layout of different block units in the same third-level region 13 is the same.

[0079] The same block unit contains SRAF graphic structures 20 with different types, different spacing parameters, and different line length parameters.

[0080] It is understandable that the various types of SRAF pattern structures 20 are based on the structural forms that SRAF patterns may be set in actual mask applications.

[0081] In this embodiment, the line width parameters of each SRAF graphic structure 20 set in different tertiary regions 13 within the same secondary region 12 are different, and they all gradually change within a large size range. In addition, the spacing parameters or line length parameters of the same type of SRAF graphic structure 20 in each block unit are also different, thereby providing support for the calibration of the correspondence between SRAF graphic structures 20 of different sizes and cleaning process parameters. The layouts of the multiple secondary regions 12 composed of the tertiary regions 13 with gradually changing linewidth parameters are completely identical (i.e., the division method of the tertiary regions 13 and the setting method of the SRAF graphic structure 20 in the tertiary regions 13 are completely identical), and the layouts of the multiple primary regions 11 composed of each secondary region 12 are completely identical. This can greatly increase the number of identical SRAF graphic structures 20 set on the entire calibration layout. The SRAF graphic structures 20 at different positions can serve as mutual references to determine whether damage has occurred, ensuring the accuracy and reliability of the calibration results to a certain extent. They can also, to a certain extent, show the degree of difficulty in damage during the cleaning process when the same SRAF graphic structure 20 is located at different positions on the photomask. Similarly, this provides a reference for setting different types of SRAF graphics at different positions on the photomask.

[0082] Based on this, in an optional embodiment of this application, the line width parameters of the SRAF graphic structure 20 set in different tertiary regions 13 within the same secondary region 12 are different, and the line width parameters of the SRAF graphic structure 20 in different tertiary regions 13 can be gradually increased with a fixed variation step.

[0083] In one optional embodiment of this application, the spacing parameter or line length parameter of the same type of SRAF graphic structure 20 in each block unit can be gradually increased with a fixed variation step size.

[0084] like Figure 2 and Figure 3 As shown, in this embodiment, the photomask substrate 1 is uniformly divided into four primary regions 11 in a grid pattern; each primary region 11 is vertically divided into three secondary regions 12 (upper, middle, and lower), and each secondary region 12 is a rectangular area of ​​48mm × 22mm; each secondary region 12 is vertically divided into nine tertiary regions 13 from top to bottom. The starting linewidth, ending linewidth, and variation step size of these nine tertiary regions 13 can be set according to actual linewidth requirements. The linewidth parameters of the SRAF pattern structure 20 in different tertiary regions 13 can be fixed and gradually increased by a variation step size. For example, the variation step size can be set from a starting linewidth of 30nm to an ending linewidth of 110nm with a variation step size of 10nm; or the variation step size can be set from a starting linewidth of 10nm to an ending linewidth of 26nm with a variation step size of 2nm.

[0085] Each tertiary region 13 is horizontally divided into three uniformly spaced blocks (left, center, and right), each block being a rectangular region of 15nm × 2mm. Within each block, five SRAF pattern structure regions are horizontally divided sequentially. Multiple different types of SRAF pattern structures 20 can be arranged within each block; these different types of SRAF pattern structures 20 differ only in type, while all SRAF pattern structures 20 have the same linewidth parameters. In practical applications, within the same block, the area occupied by a group of different types of SRAF pattern structures 20 can be approximately the same size, for example, a 3 × 2mm area.

[0086] Furthermore, multiple SRAF graphic structures 20 of the same type can be set within a block unit according to different line width parameters, different line length parameters, or different spacing parameters.

[0087] It should be noted that, Figure 2 and Figure 3The illustration shown is only one feasible implementation of this application. In practical applications, the calibration layouts in this application can be used as a set. For example, for different types of SRAF graphic structures 20, five calibration layouts can be set as a set, with each calibration layout containing only one type of SRAF graphic structure 20. Of course, the same calibration layout can also contain two or more types of SRAF graphic structures 20. In addition, different line width parameters, spacing parameters, or line length parameters can be set between different calibration layouts in a set of calibration layouts, which can also achieve the technical solution of this application. This application does not specifically limit this aspect.

[0088] Based on the above discussion, considering that the structural materials of the SRAF pattern formed by the photomask can vary in practical applications, and that different materials of SRAF patterns can withstand different cleaning forces and other parameters, in another optional embodiment of this application, the SRAF pattern structure 20 can also be any one of the following film layer structures: pure chromium film layer structure, chromium oxide film layer structure, chromium nitride film layer structure, chromium oxynitride film layer structure, molybdenum silicon nitride film layer structure, molybdenum silicon oxynitride film layer structure, tantalum nitride film layer structure, tantalum boride nitride film layer structure, and silicon nitride film layer structure, to adapt to the calibration of cleaning parameters corresponding to photomasks of different materials.

[0089] like Figures 4 to 13 As shown, in an optional embodiment of this application, the SRAF graphic structure 20 is disposed within a block unit and includes at least one of five types: dense SRAF structure 201, single-sided main graphic SRAF structure 202, middle main graphic SRAF structure 203, short-line dense SRAF structure 204, and single-sided main graphic short-line SRAF structure 205; wherein, the specific composition of each different type of SRAF graphic structure 20 is as follows:

[0090] The dense SRAF structure 201 includes multiple long lines 21 that are parallel to each other, equally spaced, and of the same length;

[0091] The single-sided main graphic SRAF structure 202 includes a main graphic structure 22 and multiple long line structures 21 that are parallel to each other, equally spaced, and have the same line length parameter on one side of the main graphic structure 22.

[0092] The central main graphic SRAF structure includes multiple long line structures 21 that are parallel to each other, equally spaced, and have the same line length parameter, as well as two main graphic structures 22 set on both sides of each long line structure 21.

[0093] The short-line dense SRAF structure 204 includes multiple short-line structures 23 arranged in an array with the same line length parameter;

[0094] The single-sided main graphic short line SRAF structure 205 includes a main graphic structure 22 and multiple short line structures 23 located on one side of the main graphic, arranged in an array and having the same line length parameter;

[0095] In this context, the line width parameters are all the same in the same SRAF graphic structure 20; and the spacing parameters in the same SRAF graphic structure 20 are all integer multiples of the line width parameters.

[0096] Based on the structural form of SRAF patterns in a photomask, it is known that they generally exist in the form of rectangular structures with length and width dimensions on the nanometer scale. Therefore, on the rectangular photomask substrate 1, the X-axis and Y-axis directions can be defined as directions parallel to the two adjacent sides of the photomask substrate 1, respectively. In each SRAF pattern structure 20, the two sides of each rectangular structural unit (e.g., long line structure 21 and short line structure 23) are also parallel to the X-axis and Y-axis directions, respectively. Based on this, the dimensional parameter of each rectangular structural unit in the X-axis direction is used as its linewidth parameter, and the dimensional parameter in the Y-axis direction is used as its linelength parameter. Furthermore, the long line structure 21 is the linelength parameter (e.g., ... Figure 4 , Figure 6 and Figure 8 In the example, c1) is a structural unit with a line width parameter of more than 10 times, while short line structure 23 is a structural unit with a line length parameter (e.g., ...). Figure 10 and Figure 12 The c2 in the model is a structural unit that is less than 10 times the linewidth parameter.

[0097] In addition, such as Figure 4 and Figure 5 As shown, in the same dense SRAF structure 201, the dimension parameter 'a' of each long line structure 21 in the X-axis direction is used as its linewidth parameter, while the dimension parameter 'c1' in the Y-axis direction is used as its linelength parameter. The linewidth parameters between each long line structure 21 (e.g., ...) Figure 4 In all cases, a) are the same, and the line length parameter (e.g.) Figure 4 , Figure 6 and Figure 8 The c1 in the text is also the same; the spacing parameter refers to the distance between two adjacent long line structures 21 in the X-axis direction (e.g., ...). Figure 4 (b) In this context, the spacing parameter is an integer multiple of the line width parameter of the long line structure 21. The spacing parameter of each long line structure 21 can be equal to the line width parameter a of the long line structure 21, or it can be an integer multiple of the line width parameter a, such as 2a, 3a, etc.

[0098] like Figure 10 and Figure 11As shown, in the same short-line dense SRAF structure 204, the dimension parameter 'a' of each short-line structure 23 in the X-axis direction is used as its line width parameter, while the dimension parameter 'c2' in the Y-axis direction is used as its line length parameter. The line width parameters of each short-line structure 23 (e.g., ...) Figure 10 In all cases, a) are the same, and the line length parameter (e.g.) Figure 10 and Figure 12 The c2 in the text is also the same, while the spacing parameters include the X spacing parameters (such as...). Figure 10 and Figure 12 bx) and Y spacing parameters (e.g. Figure 10 and Figure 12 In the figure, the X-space parameter (by) refers to the spacing between two adjacent short line structures 23 along the X-axis, and the Y-space parameter refers to the spacing between two adjacent short line structures 23 along the Y-axis. The X-space parameter and the Y-space parameter are not necessarily the same, but both should be integer multiples of the linewidth parameter of the short line structure 23. The X-space parameter of each short line structure 23 can be equal to the linewidth parameter a, or it can be an integer multiple of the linewidth parameter a, such as 2a, 3a, etc.

[0099] In addition, such as Figure 6 , Figure 8 and Figure 12 As shown, the single-sided main pattern SRAF structure 202, the middle main pattern SRAF structure 203, and the single-sided main pattern short line SRAF structure 205, in addition to structural units such as long line structure 21 and short line structure 23, further include a main pattern structure 22. This main pattern structure is a structural unit that simulates the mask function in an actual photomask. By mixing the main pattern structure 22 with the long line structure 21 and the short line structure 23 to form the SRAF pattern structure 20, it can more realistically simulate the actual application scenario of the SRAF pattern, thereby ensuring the reliability of the calibrated cleaning process parameters. Specifically, the main pattern structure 22 can be a rectangular structure with length and width parallel to the X-axis and Y-axis, respectively.

[0100] like Figure 6 and Figure 7 As shown, in the single-sided main graphic SRAF structure 202, the dimensions of the main graphic structure 22 in the Y-axis direction and the line length parameters of the long line structure 21 (such as...) Figure 6 The area of ​​the main graphic structure 22 is the same as that of the single-sided main graphic SRAF structure 202, and the area of ​​the main graphic structure 22 can be more than half the area of ​​the single-sided main graphic SRAF structure 202. In addition, the spacing parameter in the same single-sided main graphic SRAF structure 202 refers to the spacing dimension along the X-axis between two adjacent long line structures 21 (e.g., c1). Figure 6(b) and the spacing between the main graphic structure 22 and the nearest long line structure 21 in the X-axis direction. Generally, these two spacing dimensions are equal and are integer multiples of the line width parameter of the long line structure 21.

[0101] like Figure 8 and Figure 9 As shown, in the central main graphic SRAF structure 203, a main graphic structure 22 is set on each side of several parallel long line structures 21. The dimensions of the two main graphic structures 22 in the Y-axis direction are the same as the line length parameters of the long line structures 21 (e.g., ...). Figure 8 The two main graphic structures 22 are identical (c1 in the original text), and can be completely symmetrical. The sum of the areas of the multiple long line structures 21 can be greater than half the total area of ​​the intermediate main graphic SRAF structure. Similarly, the spacing parameter in the intermediate main graphic SRAF structure 203 refers to the spacing dimension along the X-axis between two adjacent long line structures 21 (e.g., c1 in the original text). Figure 8 (b) and the spacing between the main graphic structure 22 and the nearest long line structure 21 in the X-axis direction. Generally, these two spacing dimensions are equal and are integer multiples of the line width parameter of the long line structure 21.

[0102] like Figure 12 and Figure 13 As shown, in the single-sided main graphic short line SRAF structure 205, the composition and arrangement of each short line structure 23 are the same as those in the short line dense SRAF structure 204. The difference is that the single-sided main graphic short line SRAF structure 205 also has a main graphic structure 22 on one side of each array of short line structures 23 in the X-axis direction. The spacing parameter in this single-sided main graphic short line SRAF structure 205 refers to the X-spacing dimension (e.g., the distance between adjacent short line structures 23 along the X-axis direction) between two adjacent short line structures 23. Figure 12 In the text (bx), the Y-spacing dimension along the Y-axis between two adjacent short line structures 23 (e.g., bx). Figure 12 In the X-axis direction, the spacing between the main graphic structure 22 and the nearest short line structure 23 (equal to the X-spacing dimension mentioned above) is generally equal to the spacing between the main graphic structure 22 and the nearest short line structure 23. These three spacing dimensions are generally equal and are all integer multiples of the line width parameter of the short line structure 23.

[0103] It is understood that the SRAF graphic structure 20 in this application is not limited to the above 5 different structure types. In practical applications, it may also include other structure types, such as a mixed layout of short line structure 23 and long line structure 21, and other types of SRAF graphic structures 20, which will not be listed here.

[0104] As described above, in this embodiment, a tertiary region 13 containing multiple SRAF graphic structures 20 with different linewidth parameters needs to be set in the same secondary region 12. Each tertiary region 13 also contains SRAF graphic structures 20 with different structural types, so as to realize the calibration of the correlation between SRAF graphic structures 20 and cleaning process parameters.

[0105] Therefore, in another optional embodiment of this application, the calibration layout may further include:

[0106] The linewidth parameter of the SRAF pattern structure 20 is set between 10nm and 110nm;

[0107] The spacing parameters of the SRAF pattern structure 20 are set between 60nm and 200nm;

[0108] In the SRAF pattern structure 20, the line length parameter of the long line structure 22 is set between 1um and 100um, and the line length parameter of the short line structure 23 is set between 10nm and 1um.

[0109] Accordingly, to ensure the rationality of the layout of each SRAF graphic structure 20, if the line length parameter of the long line structure 21 in an SRAF graphic structure 20 within a block unit is relatively large, then the line length parameter of the short line structure 23 in that block unit should also be set larger, to avoid the line length parameters of the long line structure 21 and the short line structure 23 in the same block unit being close. Furthermore, within the same third-level region 13, in all SRAF graphic structures 20, the Y-spacing parameter of adjacent short line structures 23 in the Y-axis direction can be equal to the line width parameter of the short line structure 23.

[0110] like Figure 14 and Figure 15 As shown, Figure 14 and Figure 15 The diagram shown is a schematic diagram of the arrangement of dense SRAF structure 201 and short-line dense SRAF structure 204 in the same block unit under different spacing parameters.

[0111] Within the same block unit, multiple SRAF graphic structures 20 of the same type can be set vertically, and each has a different line length parameter. Multiple SRAF graphic structures 20 of the same type and with the same line length parameter can be set according to different spacing parameters. For example, in each block unit, the line length of the long line structure 21 of the same type of SRAF graphic structure 20 is 5um, and the line length parameter of the short line structure 23 is 300nm, while the spacing parameter gradually changes according to 1 times the line width, 2 times the line width, and 3 times the line width.

[0112] Further optionally, within the same block unit, the spacing parameter between SRAF pattern structures 20 of the same type gradually varies between 60nm and 200nm, the line length parameter of the long line structure 21 gradually varies between 1um and 10um, and the line length parameter of the short line structure 23 gradually varies between 10nm and 1um.

[0113] Accordingly, to ensure the rationality of the layout of each SRAF graphic structure 20, if the line length parameter of the long line structure 21 in an SRAF graphic structure 20 within a block unit is relatively large, then the line length parameter of the short line structure 23 in that block unit should also be set larger to avoid the line length parameters of the long line structure 21 and the short line structure 23 in the same block unit being close. Furthermore, within the same block unit and the same type of SRAF graphic structure area, the Y-spacing parameter of adjacent short line structures 23 in the Y-axis direction can be equal to the line width parameter of the short line structure 23 in all SRAF graphic structures 20.

[0114] Taking the same type of SRAF graphic structure area within the same block unit as an example, where the line width parameter of all SRAF graphic structures 20 is 70nm, the line length parameters of the long line structure 21 that needs to be set can be 1um, 5um, 10um, or 15um; the corresponding line length parameters of the short line structure 23 that needs to be set can be 100nm, 300nm, or 700nm; the x-spacing parameters that need to be set are 1 times the line width, 2 times the line width, or 3 times the line width; and the y-spacing parameter is 1 times the line width.

[0115] Of course, the above-mentioned method of dividing the blocks and setting the structural parameters of each SRAF graphic structure 20 in each block is only one optional implementation method in this application. In practical applications, the appropriate number and arrangement can be selected based on actual needs. This application does not specifically limit this.

[0116] In another optional embodiment of this application, the thickness parameter of the SRAF pattern structure 20 is the same among different SRAF pattern structures 20, and can be set to 10nm~120nm. The thickness of the SRAF within the same layout remains consistent, and the thickness of the SRAF pattern structure 20 can be any value from 10nm to 120nm, depending on the actual requirements.

[0117] In summary, this application forms multiple SRAF pattern structures of different structural types on the same photomask substrate. For the same type of SRAF pattern structure, multiple SRAF pattern structures with different dimensional parameters such as linewidth, line length, and spacing are set. Furthermore, multiple identical SRAF pattern structures are set at multiple different locations on the photomask substrate, thereby simulating SRAF patterns with different dimensional parameters and positions in a real photomask. This allows for the calibration pattern to be cleaned under various cleaning process parameters of a cleaning machine. Based on the damage to the SRAF pattern structure in the calibration pattern, the cleaning process parameters corresponding to the cleaning machine when cleaning SRAF pattern structures with different dimensional parameters are calibrated. This provides accurate and reliable data for cleaning photomask structures with SRAF patterns, largely avoiding damage to photomasks with SRAF patterns during cleaning and helping to ensure the accuracy of semiconductor photolithography exposure.

[0118] Based on any of the above embodiments, this application also provides a calibration method for photomask cleaning process parameters, which is applied to the calibration layout of photomask cleaning process parameters as described in any of the above claims.

[0119] like Figure 16 As shown in a specific embodiment of this application, the calibration method for the photomask cleaning process parameters may include:

[0120] S1: Clean the calibration pattern according to different cleaning process parameters;

[0121] S2: Perform laser testing on the cleaned calibration layout to obtain a test image of each SRAF graphic structure on the cleaned calibration layout;

[0122] S3: Compare the test images corresponding to the same SRAF graphic structure at different positions on the calibration pattern to obtain the size parameters of the SRAF graphic structure with cleaning damage for each type of SRAF graphic structure; the size parameters include line width parameters, spacing parameters and line length parameters.

[0123] S4: Based on the dimensional parameters of the SRAF graphic structure with cleaning damage, determine the calibration cleaning process parameters for non-destructive cleaning of different types of SRAF graphic structures.

[0124] It should be noted that the cleaning process parameters specified in this embodiment may include, but are not limited to, the acoustic frequency and power of the cleaning sound wave, the gas flow rate and liquid flow rate of the two fluids, the cleaning time, and the working distance. In the actual calibration process, parameters with relatively smaller acoustic frequency, gas or liquid flow rate, and cleaning time can be selected first to clean the calibration pattern. After one cleaning cycle, a laser can be used to inspect the cleaned calibration pattern and obtain a test image. Obviously, there will be differences between the test images of the same SRAF pattern structure with and without damage.

[0125] During actual testing, the structural type, size parameters, and position coordinates of each SRAF graphic structure can be recorded. The size parameters are the line width, line length, and spacing parameters mentioned above. The position coordinates can be represented by the location on the photomask substrate, which can be indicated by which first-level region, second-level region, third-level region, or which row and column of which block in the third-level region.

[0126] After acquiring the test images, test images corresponding to multiple SRAF pattern structures with the same structural type and size parameters but different position coordinates can be compared with each other. If they are all completely identical, it means that the SRAF pattern structure corresponding to that size parameter will not be damaged under the current cleaning process parameters. Conversely, if one or more SRAF pattern structures are damaged, the probability of damage can be determined based on the proportion of damaged SRAF pattern structures, which can provide a reference for subsequent actual cleaning of semiconductor photomask structures.

[0127] After recording the damage conditions corresponding to a set of cleaning process parameters, one of the cleaning process parameters can be gradually increased, and the above process can be repeated until the damage conditions of different types and sizes of parameters under various different cleaning process parameters are recorded. Finally, based on the recorded data, the correlation between the cleaning process parameters and different types and sizes of parameters can be analyzed and determined, that is, the calibration of the cleaning process parameters is completed.

[0128] Based on the above discussion, in another optional embodiment of this application, before cleaning the calibration pattern according to different cleaning process parameters, the following may also be included:

[0129] A priori laser test is performed on the calibration pattern to obtain a priori test image;

[0130] Accordingly, the process of comparing the test images corresponding to different primary regions in the same calibration map to determine the calibration cleaning process parameters includes:

[0131] By comparing the prior test image and the test image of the same first-level region in the same calibration pattern, and by comparing the test images corresponding to different first-level regions in the same calibration pattern, the type and size parameters of the SRAF graphic structure that actually caused the damage by the cleaning process parameters are obtained, and the calibration cleaning process parameters for no damage corresponding to each different SRAF graphic structure are determined.

[0132] It should be noted that before actual cleaning, some SRAF image structures may inherently possess defects or damage. To avoid these defects and damage being caused by the current cleaning process parameters, when comparing test images of different SRAF image structures, it is also necessary to compare them with prior test images of the calibration layout before cleaning to obtain more accurate calibration process parameters. Furthermore, it is understood that during the first cleaning of the calibration layout, the prior test image can be the test image acquired before cleaning. However, if the calibration layout undergoes multiple cleaning processes with different parameters, then the prior test image is the test image measured after the previous cleaning and before the current cleaning.

[0133] Based on the above discussion, in another optional embodiment of this application, the calibration method may further include:

[0134] The calibration pattern that obtains the same calibration cleaning process parameters is used as the inspection calibration pattern;

[0135] According to the set time cycle, the calibration cleaning process parameters obtained from the previous calibration are used to clean the test calibration pattern in order to check whether the current calibration cleaning process parameters are accurate. If not, the cleaning machine is subjected to aging and damage detection for confirmation.

[0136] In this embodiment, it is further considered that as the cleaning machine is used for a longer period of time, its actual cleaning conditions may change. Even under the same cleaning process parameters, the damage to the SRAF graphic structure may change. Therefore, under the same calibrated cleaning process parameters, the damage to the SRAF graphic structure can be used to determine whether the cleaning machine is damaged or aged, and whether parts repair or maintenance is required.

[0137] Further, optionally, in another embodiment of this application, the calibration method may further include:

[0138] Multiple calibration patterns with the same SRAF pattern structure are prepared in advance according to different coating processes;

[0139] The calibration patterns were cleaned using the same cleaning process parameters to determine the undamaged linewidth parameters of the undamaged SRAF image structure in each calibration pattern, in order to calibrate the adhesion of different coating processes.

[0140] The calibration layout in this embodiment can be used not only to calibrate the cleaning process parameters of the cleaning machine, but also to calibrate the adhesion of the film structure formed by different coating processes in the semiconductor coating process.

[0141] That is, different coating processes are used to form the same pattern structure as the calibration pattern of this application, and the same cleaning process parameters are used to clean the calibration patterns formed by different coating processes. The smallest undamaged linewidth parameter in different SRAF pattern structures in different calibration patterns is determined. The undamaged linewidth parameters are compared. The film structure formed by the coating process of the calibration pattern with the smallest undamaged linewidth parameter obviously has the strongest adhesion.

[0142] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that the elements inherent in a process, method, article, or apparatus that includes a list of elements are included. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element. Additionally, portions of the technical solutions provided in the embodiments of this application that are consistent with the implementation principles of corresponding technical solutions in the prior art have not been described in detail to avoid excessive elaboration.

[0143] This article uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. It should be noted that those skilled in the art can make several improvements and modifications to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. A reticle cleaning process parameter calibration pattern, characterized by, The mask substrate comprises at least one type of SRAF pattern structure; Wherein, for the same type of SRAF pattern structure, multiple SRAF pattern structures are provided with different line width parameters; For the same type of SRAF pattern structure with the same line width parameter, multiple SRAF pattern structures are provided with different pitch parameters; For the same type of SRAF pattern structure with the same line width parameter, multiple SRAF pattern structures are provided with different line length parameters; For the same type of SRAF pattern structure with the same line width parameter, the same pitch parameter and the same line length parameter, multiple SRAF pattern structures are provided at different positions on the mask substrate.

2. The reticle cleaning process parameter calibration mask of claim 1, wherein, The mask substrate is uniformly divided into at least two first-level regions, and the layout of each first-level region is the same; In each first-level region, at least three second-level regions are uniformly divided along the longitudinal direction, and the layout of each second-level region is the same; In each second-level region, at least nine third-level regions are uniformly divided along the longitudinal direction; The line width parameters of the SRAF pattern structures provided in the same third-level region are the same, and the line width parameters of the SRAF pattern structures provided in different third-level regions in the same second-level region are different; In each third-level region, multiple block units are uniformly divided along the transverse direction, and the layout of different block units in the same third-level region is the same; Different types of SRAF pattern structures with different pitch parameters and different line length parameters are provided in the same block unit.

3. The reticle cleaning process parameter calibration mask of claim 1, wherein, The SRAF pattern structure comprises at least any one of the following types of pattern structures: dense SRAF structure, single-sided main pattern SRAF structure, intermediate main pattern SRAF structure, short line dense SRAF structure, and single-sided main pattern short line SRAF structure; The dense SRAF structure comprises multiple first long line structures arranged in parallel and at equal intervals, and the line length of each first long line structure is the same; The single-sided main pattern SRAF structure comprises a main pattern structure and multiple long line structures arranged in parallel and at equal intervals on one side of the main pattern structure, and the line length parameters of the long line structures are the same; The intermediate main pattern SRAF structure comprises multiple long line structures arranged in parallel and at equal intervals, and the line length parameters of the long line structures are the same, and two main pattern structures are provided on both sides of each long line structure; The short line dense SRAF structure comprises multiple short line structures arranged in an array, and the line length parameters of the short line structures are the same; The single-sided main pattern short line SRAF structure comprises a main pattern structure and multiple short line structures arranged in an array on one side of the main pattern structure, and the line length parameters of the short line structures are the same; Wherein, the line width parameters in the same SRAF pattern structure are the same, and the pitch parameters in the same SRAF pattern structure are integer multiples of the line width parameters.

4. The reticle cleaning process parameter calibration mask of claim 3, wherein, The line width parameters of the SRAF pattern structure are set to be between 10 nm and 110 nm; The pitch parameters of the SRAF pattern structure are set to be between 60 nm and 200 nm; The line length parameters of the long line structures in the SRAF pattern structure are set to be between 1 um and 10 um, and the line length parameters of the short line structures are set to be between 10 nm and 1 um.

5. The reticle cleaning process parameter calibration mask of any of claims 1 to 4, wherein, The SRAF pattern structure is any one of a pure chromium film layer structure, a chromium oxide film layer structure, a chromium nitride film layer structure, a chromium oxynitride film layer structure, a molybdenum silicon nitride film layer structure, a molybdenum silicon oxynitride film layer structure, a tantalum nitride film layer structure, a boron tantalum nitride film layer structure, and a silicon nitride film layer structure.

6. The reticle cleaning process parameter calibration mask of claim 5, wherein, The thickness parameter of the SRAF pattern structure is the same and is set to 10-120 nm.

7. A method for calibrating photomask cleaning process parameters, characterized in that, The calibration pattern is applied to the cleaning process parameters of the mask in any one of claims 1-6; the calibration method comprises: cleaning the calibration pattern according to different cleaning process parameters; performing laser testing on the cleaned calibration pattern to obtain a test image of each SRAF pattern structure on the cleaned calibration pattern; comparing the test images of the same SRAF pattern structure at different positions on the calibration pattern to obtain a size parameter of the SRAF pattern structure corresponding to the cleaning damage; the size parameter includes a line width parameter, a pitch parameter, and a line length parameter; determining the calibration cleaning process parameters corresponding to the non-damage cleaning of different types of SRAF pattern structures according to the size parameter of the SRAF pattern structure corresponding to the cleaning damage.

8. The method for calibrating photomask cleaning process parameters as described in claim 7, characterized in that, Before cleaning the calibration pattern according to different cleaning process parameters, it further comprises: performing prior laser testing on the calibration pattern to obtain prior test images; Accordingly, comparing the test images corresponding to different first-level regions in the same calibration pattern to determine the calibration cleaning process parameters comprises: comparing the prior test images and the test images of the same first-level region in the same calibration pattern, and comparing the test images corresponding to different first-level regions in the same calibration pattern to obtain the type and size parameter of the SRAF pattern structure actually damaged by the cleaning process parameter, and to determine the non-damage calibration cleaning process parameter corresponding to each different SRAF pattern structure.

9. The calibration method for photomask cleaning process parameters as described in claim 7, characterized in that, It further comprises: using the calibration pattern with the same calibration cleaning process parameter obtained to verify the calibration pattern; cleaning the verification calibration pattern using the calibration cleaning process parameter obtained last time according to the set time period to verify whether the current calibration cleaning process parameter is accurate, and if not, performing aging and damage detection and confirmation on the cleaning machine.

10. The method for calibrating photomask cleaning process parameters as described in claim 7, characterized in that, It further comprises: preparing a plurality of calibration patterns with the same SRAF pattern structure according to different film plating processes; cleaning the calibration patterns using the same cleaning process parameter to determine the non-damage line width parameter of the non-damage SRAF image structure in each calibration pattern to calibrate the adhesion of different film plating processes.

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