Contact hole layout correction method based on graphic environment fitting and mask plate

Abstract

The invention provides a contact hole layout correction method based on graphic environment fitting. The method comprises the following steps: randomly determining at least one graphic area in a contact hole layout; carrying out optical proximity effect correction on the at least one pattern region based on a super-resolution photoetching model, and simultaneously obtaining an actual boundary movement amount of a contact hole pattern in the at least one pattern region; by taking the error between the minimum actual boundary movement amount and the predicted boundary movement amount as a fitting target, fitting the relationship between the graph environment characteristics of the contact hole graph in the at least one graph region and the actual boundary movement amount to obtain the fitting relationship between the graph environment of the contact hole graph and the boundary movement amount; and determining the predicted boundary movement amount of the contact hole pattern in the pattern areas except the at least one pattern area in the contact hole layout by using the fitting relationship, correcting the boundary of the corresponding contact hole pattern in the pattern areas except the at least one pattern area based on the predicted boundary movement amount, and outputting the optimized contact hole layout.

Description

Technical Field

[0001] The present disclosure relates to the field of integrated circuit technology, specifically to the field of photolithography technology, and in particular to a contact hole layout correction method based on graphic environment fitting and a mask. Background Art

[0002] With the development of integrated circuits, the requirements for lithography resolution are getting higher and higher. Traditional projection lithography technology is limited by the diffraction limit. Surface plasmons have unique super-diffraction optical properties. Using these properties to achieve super-resolution lithography can break through the diffraction limit of traditional optical imaging and focusing resolution, which is of great significance to promoting the development of the integrated circuit industry and the advancement of micro-nano processing technology.

[0003] When the super-resolution lithography system images the contact hole layout, optical proximity effects (OPE) will occur due to light diffraction and interference. Even if the contact hole patterns in the contact hole layout are the same size, the imaging results will vary greatly due to differences in the surrounding graphic environments of each contact hole pattern. This difference will affect the performance of the integrated circuit.

[0004] In order to reduce the influence of optical proximity effect, some optical proximity correction (OPC) methods have been proposed and adopted in recent years. Among them, the rule-based optical proximity correction method corrects the mask layout by establishing a correction rule library, but with the reduction of lithographic feature size, there are problems such as limited correction effect and increasingly complex correction rule library. In recent years, the model-based optical proximity correction (MBOPC) method uses the physical model of the lithography imaging process to convert OPC into a mathematical optimization problem for solution, which can obtain better optimization effect. With the evolution of lithography process nodes, the graphic density of contact hole layout is also increasing, and the amount of simulation data of MBOPC has also increased significantly. In super-resolution lithography, since the lithography imaging model cannot be expressed in an analytical way, but a full-wave numerical simulation is required, when optimizing the contact hole layout, the layout needs to be grid-divided and optimized one by one, and finally the optimization results are spliced, which will make the optimization of the full chip layout too time-consuming and seriously affect production efficiency. Summary of the invention

[0005] In view of the above problems, the present disclosure provides a contact hole layout correction method based on graphic environment fitting, which is used to at least partially solve the above technical problems.

[0006] According to a first aspect of an embodiment of the present disclosure, a contact hole layout correction method based on graphic environment fitting is provided, comprising: randomly determining at least one graphic area in the contact hole layout; performing optical proximity effect correction on the at least one graphic area based on a super-resolution lithography model, and obtaining the actual boundary movement of the contact hole graphic in the at least one graphic area; taking minimizing the error between the actual boundary movement and the predicted boundary movement as the fitting target, fitting the relationship between the graphic environment characteristics of the contact hole graphic in the at least one graphic area and the actual boundary movement, and obtaining the fitting relationship between the graphic environment and the boundary movement of the contact hole graphic; determining the predicted boundary movement of the contact hole graphic in the graphic area other than the at least one graphic area in the contact hole layout by using the fitting relationship, and correcting the boundary of the corresponding contact hole graphic in the graphic area other than the at least one graphic area in the contact hole layout based on the predicted boundary movement, and outputting the optimized contact hole layout.

[0007] According to an embodiment of the present disclosure, at least one graphic area is randomly determined in a contact hole layout, including: determining the number of selected graphic areas and area sizes in the contact hole layout; randomly selecting at least one graphic area from the graphic areas in the contact hole layout according to the number of selected areas and area sizes, wherein at least one graphic area at least covers various graphic environments of the contact hole graphics in the contact hole layout, and the area size of each graphic area in the at least one graphic area is larger than the range of the contact hole graphics that is optically affected.

[0008] According to an embodiment of the present disclosure, an optical proximity effect correction is performed on at least one graphic area based on a super-resolution lithography model, and an actual boundary movement amount of a contact hole graphic in at least one graphic area is obtained, including: performing gradient iterative optimization on all contact hole graphics in at least one graphic area based on the super-resolution lithography model to obtain an optimized contact hole graphic boundary position; and determining the actual boundary movement amount of the contact hole graphic in at least one graphic area based on the optimized contact hole graphic boundary position and the contact hole graphic boundary position before optimization.

[0009] According to an embodiment of the present disclosure, with minimizing the error between the actual boundary movement and the predicted boundary movement as the fitting target, the relationship between the graphic environment characteristics of the contact hole graphic in at least one graphic area and the actual boundary movement is fitted to obtain the fitting relationship between the graphic environment of the contact hole graphic and the boundary movement, including: converting the graphic environment of the contact hole graphic into a graphic environment characteristic; taking the graphic environment characteristic vector as the independent variable and the actual boundary movement of the contact hole graphic as the dependent variable, to obtain the fitting relationship between the graphic environment of the contact hole graphic and the boundary movement, wherein the fitting objective function is the sum of the mean square error between the actual boundary movement and the predicted boundary movement.

[0010] According to an embodiment of the present disclosure, a multilayer perceptron or a deep learning network is used for fitting.

[0011] According to an embodiment of the present disclosure, the graphic environment of the contact hole graphic is converted into a graphic environment feature, including: setting the graphic environment range of the contact hole graphic based on the center of the contact hole graphic; dividing the range into grid areas with a preset step size; assigning a value to each grid in the grid area based on whether there is a contact hole graphic in each grid, and converting the graphic environment of the contact hole graphic into a graphic environment feature.

[0012] According to an embodiment of the present disclosure, the boundary of the contact hole layout is corrected based on the corresponding predicted boundary movement amount in the graphic area other than the at least one graphic area in the contact hole layout, and the optimized contact hole layout is output, including: based on the principle that the movement in the direction of the external normal is positive, the boundary position of the corresponding contact hole graphic in the graphic area other than at least one graphic area in the contact hole layout is moved based on the predicted boundary movement amount, and the corrected contact hole graphic in the graphic area other than at least one graphic area is obtained, and the optimized contact hole layout is output together with the corrected contact hole graphic in at least one graphic area.

[0013] According to an embodiment of the present disclosure, a super-resolution lithography model includes: a substrate, a metal reflective layer, a photoresist, a metal transmissive layer, an air spacer layer, and a mask layer stacked in sequence; or, a substrate, a photoresist layer, an air spacer layer, a multi-layer film structure, and a mask layer stacked in sequence; or, a substrate, a photoresist layer, a metal transmissive layer, an air spacer layer, a multi-layer film structure, and a mask layer stacked in sequence; or, a substrate, a metal reflective layer, a photoresist layer, an air spacer layer, a multi-layer film structure, and a mask layer stacked in sequence; or, a substrate, a metal reflective layer, a photoresist layer, a metal transmissive layer, an air spacer layer, a multi-layer film structure, and a mask layer stacked in sequence.

[0014] According to an embodiment of the present disclosure, the shape of the contact hole pattern includes at least one of a circle, an ellipse, a rectangle, and a square.

[0015] According to a second aspect of an embodiment of the present disclosure, a mask is provided. The mask is prepared based on a corrected mask layout, wherein the corrected mask layout includes a contact hole pattern, and the corrected mask layout is corrected using the above-mentioned contact hole layout correction method.

[0016] The contact hole layout correction method and mask based on graphic environment fitting provided by the present disclosure have at least the following technical effects:

[0017] This method randomly selects some graphic areas in the contact hole layout, uses the model-based optical proximity effect correction method to obtain the actual boundary movement of the contact hole graphic, and uses the fitting method to obtain the fitting relationship between the graphic environment and the actual boundary movement. The remaining unoptimized graphics are predicted according to their graphic environment to obtain the predicted boundary movement to complete the contact hole layout optimization. This method does not require the entire contact hole layout to be grid-divided and then corrected for the optical proximity effect, which greatly reduces the area that needs to be full-wave simulated in super-resolution lithography, thereby significantly improving the optimization efficiency of the contact hole layout in super-resolution lithography. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The above contents and other objects, features and advantages of the present disclosure will become more apparent through the following description of the embodiments of the present disclosure with reference to the accompanying drawings, in which:

[0019] Figure 1 A diagram schematically shows a contact hole layout correction method based on graphic environment fitting according to the present disclosure;

[0020] Figure 2 A schematic diagram of the structure of a super-resolution lithography model according to an embodiment of the present disclosure is schematically shown.

[0021] Figure 3 A schematic diagram of a selected graphic area according to an embodiment of the present disclosure is schematically shown.

[0022] Figure 4 The OPC result diagram based on the super-resolution lithography model according to an embodiment of the present disclosure is schematically shown.

[0023] Figure 5 The graph error according to the embodiment of the present disclosure is schematically shown as a function of the number of iterations.

[0024] Figure 6 The diagram schematically shows the statistical distribution of the movement amounts of the four boundaries of the contact hole pattern after the model-based OPC is performed according to an embodiment of the present disclosure.

[0025] Figure 7 The schematic diagram schematically shows a schematic diagram of using a multilayer perceptron to input graphic environment features and then output a predicted boundary movement amount for fitting according to an embodiment of the present disclosure.

[0026] Figure 8 A diagram schematically shows a comparison of graphic errors before and after the contact hole layout correction method according to an embodiment of the present disclosure is adopted.

[0027] Fig. 9 A schematic diagram shows a comparison of the pattern errors of the contact hole layout correction method using an embodiment of the present disclosure and after optimization using the average predicted boundary movement amount. DETAILED DESCRIPTION

[0028] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of the present disclosure. In the following detailed description, for ease of explanation, many specific details are set forth to provide a comprehensive understanding of the embodiments of the present disclosure. However, it is apparent that one or more embodiments may also be implemented without these specific details. In addition, in the following description, descriptions of known structures and technologies are omitted to avoid unnecessary confusion of the concepts of the present disclosure.

[0029] The terms used herein are only for describing specific embodiments and are not intended to limit the present disclosure. The terms "including", "comprising", etc. used herein indicate the presence of the features, steps, operations and / or components, but do not exclude the presence or addition of one or more other features, steps, operations or components. All terms (including technical and scientific terms) used herein have the meanings commonly understood by those skilled in the art unless otherwise defined. It should be noted that the terms used herein should be interpreted as having a meaning consistent with the context of this specification and should not be interpreted in an idealized or overly rigid manner.

[0030] Figure 1 A diagram schematically shows a contact hole layout correction method based on graphic environment fitting according to the present disclosure.

[0031] like Figure 1 As shown, the contact hole layout correction method based on graphic environment fitting may include operations S110 to S140.

[0032] In operation S110, at least one pattern region is randomly determined in the contact hole layout.

[0033] In operation S120, optical proximity effect correction is performed on at least one graphic region based on the super-resolution lithography model, and an actual boundary movement amount of the contact hole pattern in the at least one graphic region is obtained.

[0034] In operation S130, the relationship between the graphic environment characteristics of the contact hole graphic in at least one graphic area and the actual boundary movement amount is fitted with the goal of minimizing the error between the actual boundary movement amount and the predicted boundary movement amount to obtain a fitting relationship between the graphic environment of the contact hole graphic and the boundary movement amount.

[0035] In operation S140, the fitting relationship is used to determine the predicted boundary movement amount of the contact hole pattern in the graphic area other than at least one graphic area in the contact hole layout, and the boundary of the corresponding contact hole pattern in the graphic area other than at least one graphic area in the contact hole layout is corrected based on the predicted boundary movement amount, and the optimized contact hole layout is output.

[0036] According to an embodiment of the present disclosure, at least one graphic area may refer to a partial graphic area among all graphic areas of the contact hole layout, and the number of graphic areas may be determined based on the characteristics of the contact hole graphic distribution in the contact hole layout. The more graphic areas are selected, the better fitting results may be obtained when fitting the relationship between the graphic environment characteristics and the actual boundary movement amount, but the amount of calculation required for the model-based OPC may be greater. Therefore, the number of graphic areas can be selected according to actual application requirements, and the present disclosure does not impose any restrictions.

[0037] According to an embodiment of the present disclosure, since the number of selected graphic areas may be multiple, the selected graphic areas can be optimized one by one based on the super-resolution lithography model using the OPC method based on the super-resolution lithography model to obtain the actual boundary movement of all contact hole graphics in the graphic area.

[0038] According to an embodiment of the present disclosure, each contact hole pattern may have a corresponding pattern environment and an actual boundary movement amount. The pattern environment characterizes the distribution relationship between each contact hole pattern in at least one pattern area and the contact hole patterns around the contact hole pattern. In super-resolution lithography, the distribution of contact hole patterns around a contact hole pattern may affect the actual boundary movement amount of the contact hole pattern.

[0039] After obtaining the fitting relationship, all remaining contact hole patterns in the contact hole layout are fitted one by one according to their pattern environment characteristics to obtain the predicted boundary movement amount of each contact hole pattern. It should be understood that all remaining contact hole patterns are contact hole patterns that are not used for fitting in the process of obtaining the fitting relationship.

[0040] Through the method of the embodiment of the present disclosure, a part of the graphic area is selected from the contact hole layout for model-based OPC, and the optimization result is used to fit the relationship between the graphic environment and the boundary displacement. According to the relationship between the graphic environment and the boundary displacement obtained by fitting, the graphics in the contact hole layout are optimized according to their graphic environment, and the optimization efficiency of the contact hole layout in super-resolution lithography can be greatly improved without time-consuming full-wave simulation calculation.

[0041] In some embodiments, randomly determining at least one graphic region in the contact hole layout in operation S110 may further include:

[0042] Determine the number of selected graphic areas and area size in the contact hole layout.

[0043] At least one graphic area is randomly selected from the graphic areas in the contact hole layout according to the selected number and the area size.

[0044] According to the embodiments of the present disclosure, at least one graphic region can at least cover various graphic environments of the contact hole graphics in the contact hole layout. On the one hand, the selected graphic region can cover various graphic environments of the contact hole graphics in the layout. On the other hand, too many graphic regions will lead to excessive time consumption for model-based OPC. At the same time, the center position and each boundary position of the contact hole graphics contained in each graphic region are recorded.

[0045] The size of the graphic region can be determined according to a super-resolution lithography model, and the size of each graphic region in at least one graphic region is larger than the range of the contact hole pattern that is optically affected.

[0046] Furthermore, the shape of the contact hole pattern may include at least one of a circle, an ellipse, a rectangle, and a square. For example, for any square contact hole, the positions of the left boundary, the upper boundary, the right boundary, and the lower boundary before recording optimization can be expressed as x left1 ,y top1 , x right1 ,y bottom1 .

[0047] In some embodiments, in operation S120, performing optical proximity effect correction on at least one graphic region based on a super-resolution lithography model and obtaining an actual boundary movement amount of a contact hole pattern in at least one graphic region includes:

[0048] Based on the super-resolution lithography model, gradient iterative optimization is performed on all contact hole patterns in at least one pattern area to obtain the optimized contact hole pattern boundary position.

[0049] Based on the optimized contact hole pattern boundary position and the contact hole pattern boundary position before optimization, an actual boundary movement amount of the contact hole pattern in at least one pattern area is determined.

[0050] For example, for any contact hole pattern, the positions of the left boundary, upper boundary, right boundary and lower boundary after the optimization can be expressed as x left2 ,y top2 , x right2 ,y bottom2 , then the actual boundary movement is (x left2 -x left1 , y top2 -y top1 , x right2 -x right1 , y bottom2 -y bottom1 ).

[0051] In some embodiments, in operation S130, the graphic environment of the contact hole pattern in at least one graphic region is fitted with minimizing the error between the actual boundary movement amount and the predicted boundary movement amount as the fitting target, and the relationship between the graphic environment characteristics of the contact hole pattern in at least one graphic region and the actual boundary movement amount is fitted to obtain the fitting relationship between the graphic environment of the contact hole pattern and the boundary movement amount, including:

[0052] Convert the graphics environment of the contact hole graphic to a graphics environment feature.

[0053] Taking the graphic environment feature vector as the independent variable and the actual boundary movement of the contact hole graphic as the dependent variable, the fitting relationship between the graphic environment and the boundary movement of the contact hole graphic is obtained.

[0054] A multilayer perceptron or a deep learning network can be used for fitting. In this case, the graphic environment feature can be a matrix composed of several vectors.

[0055] According to an embodiment of the present disclosure, the objective function used in the iterative optimization may be a graphic error, and the graphic error may be defined as the sum of the mean square error between the predicted boundary movement and the actual boundary movement. The graphic error may be used to measure the fidelity of the photolithography imaging result, and its size is related to parameters such as the number of contact hole graphics and the size of the contact hole graphics. The closer the imaging result graphics are to the target graphics, the smaller the graphic error is, and the higher the fidelity of the imaging result is.

[0056] Further, in some embodiments, converting the graphic environment into the graphic environment feature may include:

[0057] Sets the graphic environment range of the contact hole graphic based on the center of the contact hole graphic.

[0058] Divide the range into grid regions with a preset step size.

[0059] Each grid in the grid area is assigned a value based on whether there is a contact hole pattern in the grid, and the graphic environment of the contact hole pattern is converted into a graphic environment feature.

[0060] For example, when converting the graphic environment of the contact hole graphic into a graphic environment feature for fitting, the range of the graphic environment can be set to R, and only other contact hole graphics that are within R of the center of the contact hole graphic in both the horizontal and vertical directions are taken into account. The area with a side length of R is divided into grids at intervals of a certain step length. When a contact hole graphic exists in the corresponding position of the grid, the grid is assigned a value of 1, otherwise the grid is assigned a value of 0. This method can be used to obtain the graphic environment feature x of each contact hole graphic. i .

[0061] In some embodiments, in operation S140, correcting the boundary of the contact hole layout in the graphic area other than the at least one graphic area in the contact hole layout based on the predicted boundary movement amount, and outputting the optimized contact hole layout may include:

[0062] Based on the principle that movement in the direction of the external normal is positive, the boundary position of the corresponding contact hole pattern in the graphic area other than at least one graphic area in the contact hole layout is moved based on the predicted boundary movement amount to obtain the corrected contact hole pattern in the graphic area other than at least one graphic area, and the optimized contact hole layout is output together with the corrected contact hole pattern in at least one graphic area.

[0063] For example, the actual boundary movement obtained by fitting is (x left2 -x left1 , y top2 -y top1 , x right2 -x right1 , y bottom2 -y bottom1 ) left2 -x left1 If positive, the left edge of the contact hole is moved x in the direction of the outer normal. left2 -x left1 , the actual boundary movement obtained by fitting is (x left2 -x left1 , y top2 -y top1 , x right2 -x right1 , y bottom2 -y bottom1 ) in y top2 -y top1 If |y is negative, the upper boundary of the contact hole is moved inward in the normal direction. top2 -y top1 |.

[0064] In some embodiments, the super-resolution lithography model may be a physical model established based on the super-resolution lithography structure. The super-resolution lithography model may include:

[0065] A substrate, a metal reflective layer, a photoresist, a metal transmission layer, an air spacer layer, and a mask layer stacked in sequence;

[0066] Alternatively, a substrate, a photoresist layer, an air spacer layer, a multilayer film structure, and a mask layer are sequentially stacked;

[0067] Alternatively, a substrate, a photoresist layer, a metal transmission layer, an air spacer layer, a multilayer film structure, and a mask layer are stacked in sequence;

[0068] Or, a substrate, a metal reflective layer, a photoresist layer, an air spacer layer, a multilayer film structure, and a mask layer stacked in sequence;

[0069] Alternatively, a substrate, a metal reflective layer, a photoresist layer, a metal transmission layer, an air spacer layer, a multi-layer film structure, and a mask layer are stacked in sequence.

[0070] The embodiment of the present disclosure also provides a mask plate, which is prepared based on a corrected mask layout, wherein the corrected mask layout includes a contact hole pattern, and the corrected mask layout can be corrected by using the above-mentioned contact hole layout correction method. For the specific details of the contact hole layout correction method, please refer to the above-mentioned embodiment part, which will not be repeated here.

[0071] In order to more clearly illustrate the contact hole layout correction method based on graphic environment fitting in the embodiment of the present disclosure, specific examples and corresponding data are listed below for illustration.

[0072] Figure 2 A schematic diagram of the structure of a super-resolution lithography model according to an embodiment of the present disclosure is schematically shown.

[0073] like Figure 2 As shown, the super-resolution lithography model in this example may include a substrate, a metal reflective layer, a photoresist layer, a metal transmission layer, an air spacer layer, and a mask layer stacked in sequence. The thickness of the mask layer is set to 40 nm, the thickness of the air spacer layer is set to 40 nm, the thickness of the metal transmission layer is set to 20 nm, the thickness of the metal reflective layer is set to 30 nm, and the thickness of the photoresist layer is set to 50 nm.

[0074] Figure 3 A schematic diagram of a selected graphic area according to an embodiment of the present disclosure is schematically shown.

[0075] like Figure 3 As shown in the figure, four randomly selected graphic areas are shown in this example. These graphic areas are the layout areas with a contact hole pattern randomly selected from the contact hole layout as the center and a side length of 2 μm. The period of the contact hole pattern in the contact hole layout is 130 nm, and the contact hole size is 50 nm.

[0076] Figure 4 The OPC result diagram based on the super-resolution lithography model according to an embodiment of the present disclosure is schematically shown.

[0077] like Figure 4 As shown in the figure, the short dashed line represents the imaging result obtained by simulation before OPC, the long dashed line represents the imaging result corresponding to the mask pattern after OPC, and the solid line represents the target pattern. Figure 4It can be seen that the imaging result of the contact hole pattern after OPC is closer to the target pattern than the imaging result without OPC, that is, the model-based OPC has a significant optimization effect on the contact hole pattern.

[0078] Figure 5 The graph error according to the embodiment of the present disclosure is schematically shown as a function of the number of iterations.

[0079] like Figure 5 As shown, the horizontal axis is the number of iterations, and the vertical axis is the graphic error between the imaging result and the target graphic. The boundary optimization of the mask graphic is achieved through OPC based on the super-resolution lithography model, so that the graphic error is reduced from 1292 to 400 after 9 iterative optimizations, which shows that the imaging result corresponding to the mask after the model-based OPC is closer to the target graphic.

[0080] Figure 6 The diagram schematically shows the statistical distribution of the movement amounts of the four boundaries of the contact hole pattern after the model-based OPC is performed according to an embodiment of the present disclosure.

[0081] like Figure 6 As shown in the figure, after the contact hole graphics in the randomly selected graphic area are subjected to model-based OPC, the movement of the four boundaries of each contact hole graphic is counted, where the outer normal direction of the boundary is positive, and the opposite is negative, and the unit is nm. It can be seen that the actual boundary movement of the upper, lower, left and right contact hole graphics in the layout is mostly distributed in the range of -3.5 nm to -1 nm, which indicates that all contact hole graphics have been reduced to varying degrees after boundary optimization.

[0082] Figure 7 The schematic diagram schematically shows a schematic diagram of using a multilayer perceptron to input graphic environment features and then output a predicted boundary movement amount for fitting according to an embodiment of the present disclosure.

[0083] like Figure 7 As shown, the environmental characteristics x of the contact hole pattern are used i As input, the output variable is the predicted boundary movement of the corresponding contact hole pattern. The goal of the fitting model is to reduce the sum of the mean square error between the actual boundary movement and the predicted boundary movement. A multilayer perceptron is used as the fitting tool, and the parameters of the hidden layer are set to 100.

[0084] Figure 8 A diagram schematically shows a comparison of graphic errors before and after the contact hole layout correction method according to an embodiment of the present disclosure is adopted.

[0085] like Figure 8As shown, after fitting and obtaining the predicted boundary movement of all graphics of the contact hole layout, the optimized contact hole layout can be output. 10 graphic areas are randomly selected in the optimized contact hole layout, and the optimization effect is verified by comparing the graphic errors of the optimized layout and the layout before optimization. The horizontal axis represents the numbers of the 10 randomly selected graphic areas, the vertical axis represents the graphic errors of the graphic areas, Pat Sur OPC represents the optimization results using the contact hole layout correction method disclosed in the present invention, and w / o is the result before optimization. It can be seen that the graphic errors of the 10 random areas after Pat Sur OPC are significantly smaller than the graphic errors before OPC, indicating that Pat Sur OPC can effectively reduce the graphic errors.

[0086] Fig. 9 A schematic diagram shows a comparison of the pattern errors of the contact hole layout correction method using an embodiment of the present disclosure and after optimization using the average predicted boundary movement amount.

[0087] like Fig. 9 As shown, Figure 8 10 randomly selected graphic areas are shown in the figure, where Mean Dis OPC represents the optimization result obtained by using the average value of the actual boundary movement of all graphics obtained by the model-based OPC method, the horizontal axis represents the numbers of the 10 randomly selected graphic areas, and the vertical axis represents the graphic error of the graphic area. It can be seen that the graphic error of Pat Sur OPC is lower than that of Mean Dis OPC, which shows that the optimization effect of the contact hole layout correction method disclosed in the present invention is better than the effect of optimizing using the average movement of the boundary, and the obtained imaging result has higher fidelity.

[0088] The embodiments of the present disclosure are described above. However, these embodiments are only for illustrative purposes and are not intended to limit the scope of the present disclosure. Although the embodiments are described above separately, this does not mean that the measures in the various embodiments cannot be used in combination to advantage. The scope of the present disclosure is defined by the attached claims and their equivalents. Without departing from the scope of the present disclosure, those skilled in the art may make a variety of substitutions and modifications, which should all fall within the scope of the present disclosure.

Claims

1. A contact hole layout correction method based on graphic environment fitting, characterized in that: include: Randomly determine at least one graphic area in the contact hole layout; Performing optical proximity effect correction on the at least one graphic region based on a super-resolution lithography model, and obtaining an actual boundary movement amount of the contact hole pattern in the at least one graphic region; Taking minimizing the error between the actual boundary movement amount and the predicted boundary movement amount as the fitting target, fitting the relationship between the graphic environment characteristics of the contact hole pattern in the at least one graphic area and the actual boundary movement amount is performed to obtain the fitting relationship between the graphic environment of the contact hole pattern and the boundary movement amount; The fitting relationship is used to determine the predicted boundary movement amount of the contact hole pattern in the graphic area other than the at least one graphic area in the contact hole layout, and the boundary of the corresponding contact hole pattern in the graphic area other than the at least one graphic area in the contact hole layout is corrected based on the predicted boundary movement amount, and the optimized contact hole layout is output.

2. The method according to claim 1, characterized in that The step of randomly determining at least one graphic area in the contact hole layout comprises: Determine the number of selected graphic areas and the area size in the contact hole layout; Randomly select the at least one graphic area from the contact hole layout according to the selected number and area size; The at least one graphic region at least covers various graphic environments of the contact hole pattern in the contact hole layout, and the area size of each graphic region in the at least one graphic region is larger than the range of the contact hole pattern that is optically affected.

3. The method according to claim 1, characterized in that The method of performing optical proximity effect correction on the at least one graphic region based on the super-resolution lithography model and obtaining the actual boundary movement of the contact hole pattern in the at least one graphic region comprises: Performing gradient iterative optimization on all contact hole patterns in the at least one pattern area based on a super-resolution lithography model to obtain an optimized contact hole pattern boundary position; Based on the optimized contact hole pattern boundary position and the contact hole pattern boundary position before optimization, an actual boundary movement amount of the contact hole pattern in the at least one pattern area is determined.

4. The method according to claim 1, characterized in that: The fitting objective is to minimize the error between the actual boundary movement amount and the predicted boundary movement amount, and to fit the relationship between the graphic environment characteristics of the contact hole pattern in the at least one graphic area and the actual boundary movement amount to obtain the fitting relationship between the graphic environment of the contact hole pattern and the boundary movement amount, including: Converting the graphic environment of the contact hole graphic into a graphic environment feature; Taking the graphic environment feature as an independent variable and the actual boundary movement amount of the contact hole graphic as a dependent variable, obtaining a fitting relationship between the graphic environment and the boundary movement amount of the contact hole graphic; The objective function of the fitting is the sum of the mean square error between the actual boundary movement and the predicted boundary movement.

5. The method according to claim 4, characterized in that Fitting is done using multilayer perceptrons or deep learning networks.

6. The method according to claim 4, characterized in that The converting the graphic environment of the contact hole graphic into a graphic environment feature comprises: Setting the graphic environment range of the contact hole graphic based on the center of the contact hole graphic; Dividing the range into grid areas with a preset step size; Each grid in the grid area is assigned a value based on whether a contact hole pattern exists in the grid, and the graphic environment of the contact hole pattern is converted into a graphic environment feature.

7. The method according to claim 1, characterized in that The step of correcting the boundary of the contact hole layout in the graphic area other than the at least one graphic area in the contact hole layout based on the predicted boundary movement amount, and outputting the optimized contact hole layout, comprises: Based on the principle that movement in the direction of the external normal is positive, the boundary position of the corresponding contact hole pattern in the graphic area other than the at least one graphic area in the contact hole layout is moved based on the predicted boundary movement amount, so as to obtain a corrected contact hole pattern in the graphic area other than the at least one graphic area, and output the optimized contact hole layout together with the corrected contact hole pattern in the at least one graphic area.

8. The method according to any one of claims 1 to 7, characterized in that: The super-resolution lithography model includes: A substrate, a metal reflective layer, a photoresist, a metal transmission layer, an air spacer layer, and a mask layer stacked in sequence; Alternatively, a substrate, a photoresist layer, an air spacer layer, a multilayer film structure, and a mask layer are sequentially stacked; Alternatively, a substrate, a photoresist layer, a metal transmission layer, an air spacer layer, a multilayer film structure, and a mask layer are stacked in sequence; Or, a substrate, a metal reflective layer, a photoresist layer, an air spacer layer, a multilayer film structure, and a mask layer stacked in sequence; Alternatively, a substrate, a metal reflective layer, a photoresist layer, a metal transmission layer, an air spacer layer, a multi-layer film structure, and a mask layer are stacked in sequence.

9. The method according to any one of claims 1 to 7, characterized in that: The shape of the contact hole pattern includes at least one of a circle, an ellipse, a rectangle and a square.

10. A mask, characterized in that: The mask plate is prepared based on a corrected mask layout, the corrected mask layout includes a contact hole pattern, and the corrected mask layout is corrected by using the contact hole layout correction method described in any one of claims 1-9.

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