Opus correction method

Abstract

The application provides an OPC correction method. The OPC correction method comprises the following steps: obtaining an original layout and an original optical model, wherein the original layout comprises special patterns; performing an inversion operation on pattern data and background data in the original layout to obtain an inverted layout, and performing an inversion operation on pattern data and background data in the original optical model to obtain an inverted optical model; performing OPC verification on the inverted layout based on the inverted optical model, wherein the OPC verification comprises special pattern area detection, so as to detect whether hot spots exist in the special patterns. In this way, the area detection of special patterns such as slanting through holes, dense patterns and / or isolated patterns can be realized, the OPC correction hot spots existing in the special patterns can be found and analyzed more intuitively, and then the OPC correction hot spots existing in the special patterns can be effectively corrected, which is beneficial to improving the publishing efficiency of the photomask and improving the production yield.

Description

Technical Field

[0001] This invention relates to the field of semiconductor technology, and in particular to an OPC correction method. Background Technology

[0002] As we move towards advanced process nodes, customer designs are becoming increasingly complex, and achieving accurate critical dimensions (CDs) is becoming more challenging, severely impacting product yield. Optical proximity correction (OPC) is widely used to improve layout accuracy and overall process window. However, for complex designs such as oblique vias, dense patterns, and isolated patterns—especially small-area patterns—the addition of sub-resolution auxiliary patterns is difficult, and the pattern mask error enhancement factor (MEEF) is large. This results in OPC hotspots, such as smaller-than-expected process windows after correction. These hotspots become potential lithography defects, affecting product performance and yield.

[0003] To promptly identify OPC correction hotspots and improve mask publishing efficiency, inspecting the OPC-corrected pattern is crucial. Currently, OPC correction pattern inspection is based on optical model checking. This involves comparing the predicted actual image on the silicon wafer with the target pattern to identify potential problem areas (such as bridging, edge placement error (EPE), and corner rounding). Currently, Bridge Check is commonly used for OPCV (OPC Verification) of special small-area patterns. Bridge Check returns all critical dimensions of a given line or space smaller than the trigger value. However, Bridge Check cannot perform area checks on some special small-area patterns, making it impossible to detect OPC correction hotspots in a timely manner. This necessitates multiple mask publications to complete OPC correction for these hotspots. Summary of the Invention

[0004] One of the objectives of this invention is to provide an OPC correction method that can detect the area of ​​special patterns such as oblique through-holes, dense patterns, and / or isolated patterns. This method can more intuitively discover and analyze OPC correction hotspots in special patterns, thereby enabling effective OPC correction of these hotspots. This is beneficial for improving the efficiency of photomask production and increasing production yield.

[0005] To achieve the above objectives, the OPC correction method provided by the present invention includes: acquiring an original layout and an original optical model, wherein the original layout includes special graphics; inverting the graphic data and background data in the original layout to obtain an inverted layout, and inverting the graphic data and background data in the original optical model to obtain an inverted optical model; and performing OPC verification on the inverted layout based on the inverted optical model, including special graphic area detection, to detect whether the special graphics have hotspots.

[0006] Optionally, if no hotspots are detected in the special graphic, the final layout is output; if hotspots are detected in the special graphic, the original layout is corrected using OPC, the OPC-corrected layout is inverted, and the OPC verification, including the detection of the area of ​​the special graphic, is performed again.

[0007] Optionally, the step of inverting the graphic data and background data in the original layout to obtain the inverted layout includes: inverting both the graphic data and background data in the original GDS file of the original layout to obtain the inverted GDS file; and inverting the graphic data and background data in the original coordinate file of the original layout to obtain the inverted coordinate file; wherein the original layout includes the original GDS file and the original coordinate file, and the inverted layout includes the inverted GDS file and the inverted coordinate file.

[0008] Optionally, the original layout can be inverted using Boolean operations or parameter encoding in the OPC system.

[0009] Optionally, the step of inverting the graphic data and background data in the original optical model to obtain the inverted optical model includes: inverting the graphic data and background data in the original optical model, exchanging the convex and indentation data of the graphic rounded corners, and inverting the layout deviation data in the original optical model.

[0010] Optionally, the OPC verification of the inverted layout based on the inverted optical model, including the detection of special graphic areas, includes: adding a special graphic area detection item to the program or system corresponding to OPC verification, and setting a threshold for the special graphic area detection; during the OPC verification, if the area detection value corresponding to the special graphic is greater than the threshold, it is determined that the special graphic does not have hotspots; if the area detection value corresponding to the special graphic is less than or equal to the threshold, it is determined that the special graphic has hotspots.

[0011] Optionally, the OPC verification of the inverted layout based on the inverted optical model, including the detection of the area of ​​special graphics, includes: outputting the area detection value corresponding to the special graphics and the simulated contour corresponding to the special graphics;

[0012] The OPC correction method further includes: determining the rounded corner profile of the special graphic based on the simulated profile.

[0013] Optionally, the original layout is a layout that has undergone conventional OPC correction.

[0014] Optionally, when performing OPC verification on the inverted layout based on the inverted optical model, including the detection of special graphic areas, the detection signal corresponding to the special graphic can be obtained.

[0015] Optionally, the special pattern includes beveled through holes, dense patterns, and / or isolated patterns.

[0016] The OPC correction method provided by this invention first obtains an original layout and an original optical model, wherein the original layout includes special graphics. Then, the graphic data and background data in the original layout are inverted to obtain an inverted layout, and the graphic data and background data in the original optical model are inverted to obtain an inverted optical model. Subsequently, based on the inverted optical model, OPC verification, including area detection of special graphics, is performed on the inverted layout to detect whether hotspots exist in the special graphics. This enables area detection of special graphics such as oblique vias, dense graphics, and / or isolated graphics, allowing for more intuitive discovery and analysis of OPC correction hotspots in special graphics. This, in turn, allows for effective OPC correction of these hotspots, improving photomask publishing efficiency and production yield. Attached Figure Description

[0017] Figure 1 This is a schematic diagram illustrating the use of the Bridge Check method in existing technologies for OPCV of special graphics.

[0018] Figure 2 This is a flowchart illustrating an embodiment of the OPC correction method provided by the present invention.

[0019] Figure 3 This is a schematic diagram illustrating the inversion operation of the original GDS file in one embodiment of the present invention.

[0020] Figure 4 This is a schematic diagram illustrating OPCV, including special graphic area detection, performed on the original layout and the inverted layout in one embodiment of the present invention. Detailed Implementation

[0021] As mentioned in the background section, conventional OPCV methods cannot currently perform area detection on special shapes. Taking OPCV using the Bridge Check method as an example, refer to... Figure 1 As shown, during the OPCV process, only special graphics in the X direction (i.e., Figure 1 (horizontal direction) and (Y direction) Figure 1 The key dimensions (vertical direction) cannot detect the area of ​​special shapes. Furthermore, the output of OPCV is the key dimensions of special shapes with hot spots in the X and Y directions, the two simulated line segments corresponding to the key dimensions of special shapes in the X and Y directions, and the ellipse defined by the two simulated line segments. This does not intuitively reflect the model outline of special shapes, which is not conducive to the discovery and analysis of OPC correction hot spots in special shapes, affecting the efficiency of OPC correction and the publication efficiency of photomasks, and thus affecting the production yield.

[0022] To address this, this application provides an OPC correction method. First, it obtains an original layout and an original optical model. The original layout includes special graphics. Then, it inverts the graphic data and background data in the original layout to obtain an inverted layout, and inverts the graphic data and background data in the original optical model to obtain an inverted optical model. Subsequently, based on the inverted optical model, it performs OPC verification on the inverted layout, including area detection of the special graphics, to detect whether hotspots exist in the special graphics. This method enables area detection of special graphics such as oblique vias, dense graphics, and / or isolated graphics, allowing for more intuitive discovery and analysis of OPC correction hotspots in these special graphics. This allows for effective OPC correction of these hotspots, improving photomask publishing efficiency and production yield.

[0023] The OPC correction method proposed in this invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. The advantages and features of this invention will become clearer from the following description. It should be noted that the drawings are all in a very simplified form and use non-precise proportions, and are only used to facilitate and clarify the illustration of the embodiments of this invention.

[0024] Figure 2 This is a schematic flowchart of an OPC correction method provided in an embodiment of the present invention. Figure 2 As shown, the OPC correction method provided in this embodiment includes:

[0025] Step S1: Obtain the original layout and the original optical model, wherein the original layout includes special graphics;

[0026] Step S2: Invert the graphic data and background data in the original layout to obtain an inverted layout, and invert the graphic data and background data in the original optical model to obtain an inverted optical model.

[0027] Step S3: Based on the inverted optical model, perform OPC verification on the inverted layout, including special pattern area detection, to detect whether there are hot spots in the special patterns.

[0028] In this embodiment, the original layout obtained in step S1 may include an original GDS (Graphic Data System) file and an original coordinate file. A GDS file is a binary file format used to describe the physical layout of an integrated circuit (IC). It records every detail of the IC layout, including the graphic shapes at different levels, the connection methods of circuit elements, etc., so that these designs can be accurately copied onto the silicon wafer during the manufacturing stage. The coordinate file is mainly used to describe the specific location information of devices in the layout. The coordinate file typically contains detailed data such as device identifiers, package information, center point coordinates, pad coordinates, layer information, and rotation angles. Both the GDS file and the coordinate file include graphic data representing the graphics and background data representing the graphic background.

[0029] The original layout includes special patterns, which include, but are not limited to, beveled vias, dense patterns, and / or isolated patterns. For example, special patterns are small-area patterns, and the area of ​​a special pattern can be less than 300nm × 500nm, such as 207nm × 396nm.

[0030] The original optical model includes graphic data representing the graphic and background data representing the graphic background, as well as data representing the corner rounding out and / or the corner rounding in of the graphic, and layout deviation data, but is not limited to these.

[0031] In this embodiment, the original layout can be the layout after conventional OPC correction. Since conventional OPCV cannot perform area detection on small-area special graphics, the special graphics in the layout after conventional OPC correction may still have hot spots that affect yield. Therefore, the layout after conventional OPC correction still needs to be improved and can be improved by the method provided in this application.

[0032] Step S2 is executed to invert the graphic data and background data in the original layout to obtain an inverted layout, and to invert the graphic data and background data in the original optical model to obtain an inverted optical model.

[0033] For example, inverting the graphic data and background data in the original layout to obtain an inverted layout includes: inverting both the graphic data and background data in the original GDS file to obtain an inverted GDS file; and inverting the graphic data and background data in the original coordinate file to obtain an inverted coordinate file, wherein the inverted layout includes an inverted GDS file and an inverted coordinate file.

[0034] Figure 3 This is a schematic diagram illustrating the inversion operation of an original GDS file according to an embodiment of the present invention. For example, as shown... Figure 3 As shown in the left-hand diagram, the striped areas in the original GDS file represent graphics, and the blank areas represent the background; after inverting the original GDS file, as shown... Figure 3 As shown in the diagram on the right, the area that was originally a graphic becomes the background, and the area that was originally the background becomes a graphic.

[0035] For example, in the original coordinate file, in the tone column, space represents the background and polygon represents the graphic, and in the tone sign column, the data corresponding to space is -1 and the data corresponding to polygon is 1; after inverting the original coordinate file, the original space becomes polygon, the original -1 becomes 1, and the original 1 becomes -1.

[0036] For example, the original layout can be inverted using Boolean operations or parameter coding in the OPC system (i.e., OPC recipe coding), but it is not limited to these methods.

[0037] For example, obtaining an inverted optical model by inverting the graphic data and background data in the original optical model includes: inverting the graphic data and background data in the original optical model, exchanging the convexity and indentation data of the graphic rounded corners, and inverting the mask bias data in the original optical model. For example, in the original optical model, the graphic data main_in is 0 and the background data field is 1; after inverting the original optical model, the graphic data main_in becomes 1 and the background data field becomes 0. For example, in the original optical model, the mask bias data Mask_BiasMF = 1; after inverting, the mask bias data Mask_BiasMF = -1.

[0038] Step S3 is executed, and OPC verification (OPCV) including special pattern area detection is performed on the inverted pattern based on the inverted optical model to detect whether there are hot spots in the special pattern.

[0039] As a key step in the OPC flow, OPCV can, on the one hand, block hot spots before final publication, saving the number of mask upgrades and thus saving on mask resources; on the other hand, it can promptly detect and correct hot spots in OPC, which is beneficial to improving product yield.

[0040] Specifically, before performing the OPC verification, a special graphic area detection item needs to be added to the program or system corresponding to the OPC verification, and a threshold for the special graphic area detection needs to be set.

[0041] During the OPC verification process, if the area detection value corresponding to the special graphic is greater than the threshold, it is determined that the special graphic does not have a hot spot; if the area detection value corresponding to the special graphic is less than or equal to the threshold, it is determined that the special graphic has a hot spot.

[0042] Figure 4 This is a schematic diagram illustrating OPCV, including special graphic area detection, performed on the original layout and the inverted layout in one embodiment of the present invention. Figure 4 As shown in the two figures above, when performing OPCV including special graphic area detection on the original layout, no detection signal corresponding to the special graphic was detected, meaning that the area detection of special graphics in OPCV could not be achieved; however, when performing OPCV including special graphic area detection after inverting the original layout and the original optical model, the detection signal corresponding to the special graphic was detected, meaning that the area detection of special graphics in OPCV was achieved.

[0043] Step S3 may further include: outputting the area detection value corresponding to the special shape and the simulated contour corresponding to the special shape. It should be noted that, compared with the existing technology that uses the Bridge check method to output the simulated line segment corresponding to the key dimension of the special shape in the set direction, this application performs OPCV including the area detection of the special shape and outputs the simulated contour corresponding to the special shape. Therefore, based on the simulated contour, the rounded corner contour of the special shape can be intuitively judged, which is more conducive to intuitively analyzing the OPC correction hotspots existing in the special shape.

[0044] After completing OPCV, if no hotspots are detected in the special graphic, the final layout is output; if hotspots are detected in the special graphic, OPC correction is performed on the original layout, the OPC-corrected layout is inverted, and the OPC verification including the detection of the area of ​​the special graphic is performed again. That is, if hotspots are detected in the special graphic, the operations of steps S2 and S3 are repeated on the corrected layout until no hotspots are detected in the special graphic.

[0045] The OPC correction method provided by this invention first obtains an original layout and an original optical model, wherein the original layout includes special graphics. Then, the graphic data and background data in the original layout are inverted to obtain an inverted layout, and the graphic data and background data in the original optical model are inverted to obtain an inverted optical model. Subsequently, based on the inverted optical model, OPC verification, including area detection of special graphics, is performed on the inverted layout to detect whether hotspots exist in the special graphics. This enables area detection of special graphics such as oblique vias, dense graphics, and / or isolated graphics, allowing for more intuitive discovery and analysis of OPC correction hotspots in special graphics. This, in turn, allows for effective OPC correction of these hotspots, improving photomask publishing efficiency and production yield.

[0046] The above description is merely a description of preferred embodiments of the present invention and is not intended to limit the scope of the present invention. Any person skilled in the art can make possible changes and modifications to the technical solutions of the present invention by utilizing the methods and techniques disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solutions of the present invention shall fall within the protection scope of the technical solutions of the present invention.

Claims

1. An OPC correction method, characterized in that, include: Obtain the original layout and the original optical model, wherein the original layout includes special patterns, and the special patterns include at least one of oblique through-holes, dense patterns and isolated patterns; Invert the graphic data and background data in the original layout to obtain the inverted layout; The graphic data and background data in the original optical model are inverted, the convexity and indentation data of the graphic rounded corners in the original optical model are swapped, and the layout deviation data in the original optical model is inverted to obtain the inverted optical model. as well as Based on the aforementioned inverted optical model, OPC verification, including special pattern area detection, is performed on the inverted layout to detect whether the special pattern has hotspots, and outputs the area detection value and simulated contour corresponding to the special pattern. Specifically, a special pattern area detection item is added to the OPC verification program or system, and a threshold for the special pattern area detection is set. During the OPC verification, if the area detection value corresponding to the special pattern is greater than the threshold, it is determined that the special pattern does not have hotspots; if the area detection value corresponding to the special pattern is less than or equal to the threshold, it is determined that the special pattern has hotspots.

2. The OPC correction method as described in claim 1, characterized in that, If no hotspots are detected in the special graphic, the final layout is output; if hotspots are detected in the special graphic, the original layout is corrected using OPC, the OPC-corrected layout is inverted, and the OPC verification, including the detection of the area of ​​the special graphic, is performed again.

3. The OPC correction method as described in claim 1, characterized in that, The step of inverting the graphic data and background data in the original layout to obtain the inverted layout includes: inverting both the graphic data and background data in the original GDS file of the original layout to obtain the inverted GDS file; and inverting the graphic data and background data in the original coordinate file of the original layout to obtain the inverted coordinate file; wherein the original layout includes the original GDS file and the original coordinate file, and the inverted layout includes the inverted GDS file and the inverted coordinate file.

4. The OPC correction method as described in claim 1, characterized in that, The original layout is inverted using Boolean operations or parameter encoding in the OPC system.

5. The OPC correction method as described in claim 1, characterized in that, The OPC correction method further includes: determining the rounded corner profile of the special graphic based on the simulated profile.

6. The OPC correction method as described in claim 1, characterized in that, The original layout is the layout after conventional OPC correction.

7. The OPC correction method as described in claim 1, characterized in that, When performing OPC verification on the inverted layout based on the inverted optical model, including the detection of special graphic areas, the detection signal corresponding to the special graphic can be obtained.

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