Prediction and correction method for photoetching process hot spots
By adjusting the lithography process specifications and pattern dimensions to create a lithography hotspot pattern library, and correcting lithography hotspots, the problem of unpredictable and uncorrectable lithography hotspots in the lithography process is solved, thus improving the efficiency and accuracy of the lithography process.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SIEN (QINGDAO) INTEGRATED CIRCUITS CO LTD
- Filing Date
- 2024-10-29
- Publication Date
- 2026-05-01
AI Technical Summary
Existing technologies struggle to effectively predict and correct hot spots in photolithography processes, leading to defects on wafers that affect circuit performance and increase costs.
By adjusting the specifications and pattern size of the photolithography process, various types of photolithography hotspot patterns are predicted and generated. These patterns are then selected and compiled into a pattern library. Based on the pattern library, the initial program is modified to form the final program, thus covering more photolithography hotspots.
It improves the efficiency of predicting and correcting hot spots in the photolithography process, reduces the occurrence of defects on the wafer, and saves time and costs.
Smart Images
Figure CN121956433A_ABST
Abstract
Description
A method for predicting and correcting hotspots in photolithography processes. Technical Field
[0001] This invention relates to the field of semiconductor integrated circuit technology, and in particular to a method for predicting and correcting hot spots in photolithography processes. Background Technology
[0002] In integrated circuit manufacturing, to successfully transfer the integrated circuit pattern onto the wafer, a mask is first fabricated based on the designed ground truth (GDS), and then the pattern on the mask is transferred onto the wafer using photolithography. Due to the optical proximity effect (OPE) in subwavelength photolithography, significant distortion occurs when exposing high-density mask circuit patterns and ultimately transferring them onto the wafer. Common defects caused by the optical proximity effect include right-angled corner rounding, line end shortening, and line width increase / decrease. Although various resolution enhancement techniques (RETs), such as Optical Proximity Correction (OPC), can be used to improve the accuracy of lithography, defects such as pinholes and bridges may still occur on the final wafer due to improper design or limitations of the technology itself. The patterned structures with these defects are called lithography hotspots, and the areas where these defective patterns are located are called lithography hotspot regions. Lithography hotspot regions may affect the performance of the final circuit or even cause functional failure.
[0003] In optical proximity correction, the industry has always adjusted the initial recipe based on the entire layout, using partial cuts of the integrated circuit layout. While this is more efficient, it is highly random, and because the program is debugged by cutting the layout locally, it cannot cover the correction of all types of lithography hotspots. Unknown lithography hotspots are often only discovered after they have already appeared on the wafer, resulting in a waste of time and cost. Summary of the Invention
[0004] The purpose of this invention is to provide a method for predicting and correcting hot spots in the photolithography process, which can predict and correct hot spots in the product photolithography process at the OPC stage, avoiding the discovery of hot spots only after they appear on the wafer, thus saving time and costs.
[0005] To address the aforementioned technical problems, this invention provides a method for predicting and correcting hotspots in photolithography processes, comprising the following steps:
[0006] Import the product layout into the initial version of the program;
[0007] Adjust the specifications of the initial program along the direction in which the photolithography hotspots are formed to obtain multiple initial photolithography hotspot patterns of various types.
[0008] Centered on the geometric center of the photolithography hotspot in the initial photolithography hotspot pattern, a portion of the initial photolithography hotspot pattern is selected as the photolithography hotspot region with a preset size. The size of the pattern in the photolithography hotspot region is changed along the direction that aggravates the photolithography hotspot, and a new photolithography hotspot pattern is formed from the initial photolithography hotspot pattern.
[0009] The new photolithography hotspot patterns are screened to ensure that the new photolithography hotspot patterns are not duplicated.
[0010] The selected new photolithography hotspot patterns are used to form a photolithography hotspot pattern library; and
[0011] The initial program is debugged based on the graphics in the lithography process hotspot graphics library to form the final program, and the final program is used to correct the layout.
[0012] Optionally, when the hot spot type of the photolithography process is a broken line, the method for changing the size of the pattern in the hot spot area along the direction that aggravates the hot spot includes: shrinking each edge of the pattern in the hot spot area inward by a preset distance along the direction perpendicular to the edge.
[0013] When the hot spot type of the photolithography process is bridging, the method for changing the size of the pattern in the hot spot area along the direction that aggravates the hot spot includes: extending each edge of the pattern in the hot spot area outward by a preset distance in a direction perpendicular to the edge.
[0014] Optionally, the method for screening the new photolithography hotspot patterns includes:
[0015] Determine the layout coordinates corresponding to the geometric center of the photolithography hotspot in the new photolithography hotspot pattern;
[0016] The new photolithography hotspot patterns are selected based on their graphic appearance; or / and
[0017] The new lithography hotspot patterns are selected according to the priority of the lithography hotspot type.
[0018] Optionally, the method for filtering the new photolithography hotspot patterns according to their pattern appearance includes: for multiple new photolithography hotspot patterns with repeated pattern appearances, retaining the new photolithography hotspot pattern with the most severe photolithography hotspot.
[0019] Optionally, the method for filtering the new lithography hotspot patterns according to the priority of the lithography hotspot type includes: for multiple new lithography hotspot patterns with the same layout coordinates but different types, retaining the new lithography hotspot pattern with the highest priority of the lithography hotspot type.
[0020] Optionally, the priority of the photolithography hotspot types from largest to smallest is as follows: broken line, bridging > one-dimensional negative EPE, one-dimensional positive EPE > two-dimensional line end negative EPE, two-dimensional line end positive EPE > two-dimensional interval end negative EPE, two-dimensional interval end positive EPE > wrapping upper hole, wrapping lower hole > pattern area.
[0021] Optionally, the method for assembling the new photolithography process hotspot patterns into a photolithography process hotspot pattern library after filtering includes:
[0022] A cross mark is set within the area of the photolithography hotspot, with the geometric center of the hotspot as the center;
[0023] The hotspot region of the photolithography process is extracted from the new photolithography hotspot pattern as the final photolithography hotspot pattern;
[0024] The multiple final photolithography process hotspot patterns are arranged in a regular pattern to form the photolithography process hotspot pattern library.
[0025] Optionally, multiple layouts of multiple products can be imported into the initial version of the program to obtain a photolithography hotspot graphic library of multiple layouts.
[0026] Optionally, it also includes merging multiple lithography process hotspot pattern libraries into a single lithography process hotspot pattern library.
[0027] Optionally, the method for debugging the initial program to form the final program based on the graphics in the lithography process hotspot graphics library includes: importing the lithography process hotspot graphics library into the initial program, using the initial program to correct the lithography process hotspot graphics in the lithography process hotspot graphics library, and the correction process is the process of continuously debugging the initial program until all lithography process hotspots are resolved to form the final program.
[0028] In summary, the method for predicting and correcting lithography hotspots provided by this invention first imports the product layout into a preliminary program. Then, the specifications of the preliminary program are adjusted along the direction in which the lithography hotspots are formed to obtain multiple initial lithography hotspot patterns of various types. Next, using the geometric center of the lithography hotspot in the initial lithography hotspot pattern as the center, a portion of the initial lithography hotspot pattern is selected as the lithography hotspot region with a preset size. The size of the pattern within the lithography hotspot region is changed along the direction that intensifies the lithography hotspot, forming a new lithography hotspot pattern from the initial lithography hotspot pattern. The new lithography hotspot patterns are then screened to ensure that they are not duplicated. The screened new lithography hotspot patterns are then compiled into a lithography hotspot pattern library. Based on the patterns in the lithography hotspot pattern library, the preliminary program is debugged to form a final program, and the final program is used to correct the layout. This invention creates multiple lithography hotspot patterns by adjusting specifications and changing the size of the patterns, forming a lithography hotspot pattern library. An initial version of the program is used to modify the patterns in the library to create a final version. This final version is more targeted and sensitive to lithography hotspots, covering the correction of most lithography hotspots. All potential lithography hotspots in the product can be corrected, achieving the goal of predicting and correcting lithography hotspots at the OPC stage. This avoids discovering lithography hotspots only after they appear on the wafer, thus saving time and costs.
[0029] Meanwhile, the initial program is debugged by modifying the graphics in the lithography process hotspot graphics library, which is more efficient than the existing method of debugging the initial program by extracting a partial layout. The graphics types are more comprehensive and the lithography process hotspots are more targeted. Attached Figure Description
[0030] Figure 1 is a flowchart of a method for predicting and correcting hot spots in photolithography processes according to an embodiment of the present invention.
[0031] Figure 2 is an initial photolithography hotspot pattern of a broken line provided in an embodiment of the present invention.
[0032] Figure 3 shows the hotspot pattern of the new photolithography process corresponding to Figure 2.
[0033] Figure 4 is a bridging initial photolithography hotspot pattern provided in an embodiment of the present invention.
[0034] Figure 5 shows the hotspot pattern of the new photolithography process corresponding to Figure 4.
[0035] Figures 6 and 7 show two photolithography hotspot patterns of the same type but different layout coordinates.
[0036] Figure 8 is a new photolithography hotspot pattern after setting cross marks according to an embodiment of the present invention.
[0037] Figure 9 is a lithography hotspot graphic library corresponding to a layout provided in an embodiment of the present invention.
[0038] Figure 10 shows a lithography hotspot graphic library after merging multiple lithography hotspot graphic libraries provided in an embodiment of the present invention. Detailed Implementation
[0039] To make the objectives, advantages, and features of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that the drawings are all in a very simplified form and are not drawn to scale, and are only used to facilitate and clarify the explanation of the embodiments of this invention. Furthermore, the structures shown in the drawings are often part of the actual structures. In particular, different figures may emphasize different aspects and may sometimes use different scales.
[0040] As used herein, the singular forms “a,” “an,” and “the” include plural objects unless otherwise expressly indicated. As used herein, the term “or” is generally used to include “and / or” unless otherwise expressly indicated. As used herein, the term “a number” is generally used to include “at least one” unless otherwise expressly indicated. As used herein, the term “at least two” is generally used to include “two or more” unless otherwise expressly indicated. Furthermore, the terms “first,” “second,” and “third” are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as “first,” “second,” or “third” may explicitly or implicitly include one or at least two of that feature.
[0041] Figure 1 is a flowchart of a method for predicting and correcting hot spots in a photolithography process according to an embodiment of the present invention. Referring to Figure 1, the method for predicting and correcting hot spots in a photolithography process according to an embodiment of the present invention includes the following steps:
[0042] S1: Import the product layout into the initial version of the program;
[0043] S2: Adjust the specifications of the initial program along the direction of forming photolithography hotspots to obtain multiple initial photolithography hotspot patterns of various types;
[0044] S3: Taking the geometric center of the photolithography hotspot in the initial photolithography hotspot pattern as the center, select a portion of the initial photolithography hotspot pattern as the photolithography hotspot area with a preset size, change the size of the pattern in the photolithography hotspot area along the direction of aggravating the photolithography hotspot, and form a new photolithography hotspot pattern from the initial photolithography hotspot pattern.
[0045] S4: The new photolithography hotspot patterns are screened to ensure that the new photolithography hotspot patterns are not repeated;
[0046] S5: The newly selected photolithography hotspot patterns are compiled into a photolithography hotspot pattern library; and
[0047] S6: Based on the graphics in the lithography process hotspot graphics library, debug the initial program to form the final program, and use the final program to correct the layout.
[0048] In step S1, the product layout is imported into the initial version of the program.
[0049] In this embodiment, layouts of multiple products can be imported into a first-recipe program. Each product can have one or more layouts. The first-recipe program refers to a program that is sufficient to predict and correct most types of patterns, but cannot predict and correct hot spots in the lithography process.
[0050] In step S2, the specifications of the initial program are adjusted along the direction in which the photolithography hotspots are formed to obtain multiple initial photolithography hotspot patterns of various types.
[0051] The initial specifications (SPEC) are relatively loose and cannot predict a sufficient number and type of lithography hotspots. Although some types of lithography hotspots show a quantity of 0, they may form obvious lithography hotspots during actual wafer exposure. This means that a sufficient number and type of lithography hotspots need to be predicted during the OPC correction stage.
[0052] In this embodiment, the specifications of the initial program are adjusted in a direction that is more likely to form lithography hotspots, so that patterns that did not originally constitute lithography hotspots become lithography hotspots after the specifications are adjusted. By adjusting the specifications, a tighter temporary specification is formed, which allows for the prediction of more lithography hotspots in the lithography hotspot pre-test.
[0053] Table 1
[0054]
[0055] Table 1 shows the number of lithography hotspots before and after the specification adjustment for each type of hotspot in the lithography process. EPE (Edge Placement Error) refers to the edge placement error between the contour (the simulated contour predicted by the OPC model before exposure) and the ADI target value (the target value after lithography development). One-dimensional negative EPE means that at the one-dimensional pattern, the difference between the contour and the ADI edge is negative, and the contour is inside the ADI. One-dimensional positive EPE means that at the one-dimensional pattern, the difference between the contour and the ADI edge is positive, and the contour is outside the ADI. Two-dimensional space end negative EPE means that at the two-dimensional pattern space end, the difference between the contour and the ADI edge is negative, and the contour is inside the ADI. Two-dimensional space end positive EPE means that at the two-dimensional pattern space end, the difference between the contour and the ADI edge is positive, and the contour is outside the ADI. Two-dimensional line end negative EPE means that at the two-dimensional pattern line end... (end) The difference between the contour and the edge of ADI is negative, and the contour is inside ADI; Positive EPE for 2D line ends refers to the line end of a 2D graphic, where the difference between the contour and the edge of ADI is positive, and the contour is outside ADI; Upper hole enc refers to the coverage of the contour with the previous layer hole; Down hole enc refers to the coverage of the contour with the subsequent layer hole; Graphic area refers to the smaller graphic area in the layout.
[0056] As shown in Table 1, the number of lithography hotspots was 0 under the original specification. After adjusting the specification, the number of lithography hotspots increased under the new specification. For example, for the pinch, there were no lithography hotspots under the original specification X1 (e.g., X1 is 170nm), but after adjusting the specification to X1+0.010 (e.g., adjusted to 180nm), the number of lithography hotspots increased to 4414. For the other lithography hotspots, X2, X3 to X11 in the original specification all represent specific values. After adjusting these values (specification shrinkage), the number of lithography hotspots increased.
[0057] By adjusting the specifications, as many suspected lithography hotspots of each type as possible can be identified. The range of specification adjustment for each type of lithography hotspot can be determined according to actual needs. In one embodiment of the present invention, multiple initial lithography hotspot patterns of the same type can be obtained according to the severity of the hotspots. For example, for a broken line, if the original specification is 170nm and the specification is adjusted to 180nm, then from 170nm (excluding 170nm) to 180nm, the severity of the hotspot decreases from the most severe to the least severe. The initial lithography hotspot patterns containing the broken line are obtained sequentially according to the broken line width from 170nm (excluding 170nm) to 180nm. Of course, this is not the only possible method.
[0058] It should be noted that in this embodiment, multiple initial lithography hotspot patterns of various types are newly predicted by adjusting the specifications. However, it is possible that there are no actual lithography hotspots in the initial lithography hotspot patterns. The actual lithography hotspots may be transformed by changing the size of the patterns later.
[0059] In step S3, taking the geometric center of the photolithography hotspot in the initial photolithography hotspot pattern as the center, a portion of the initial photolithography hotspot pattern is selected as the photolithography hotspot region with a preset size. The size of the pattern in the photolithography hotspot region is changed along the direction that aggravates the photolithography hotspot, and a new photolithography hotspot pattern is formed from the initial photolithography hotspot pattern.
[0060] Figure 2 shows an initial lithography hotspot pattern of a broken line provided in an embodiment of the present invention. Figure 3 shows a new lithography hotspot pattern corresponding to Figure 2. Referring to Figure 2, the lithography hotspot type is a broken line. A portion of the initial lithography hotspot pattern is selected as the lithography hotspot region with a preset size centered on the geometric center O of the lithography hotspot, as shown in the red box in Figure 2. The preset size can be determined manually, for example, based on the area required to intensify the lithography hotspot. An exemplary preset size is 0.2 μm. The lithography hotspot region can be a square centered on the geometric center O of the lithography hotspot, but it is not limited to a square; it can also be other shapes known to those skilled in the art. Then, the size of the pattern within the lithography hotspot region is changed along a direction more conducive to forming the lithography hotspot. Specifically, each edge of the pattern within the lithography hotspot region is contracted inward by a preset distance along a direction perpendicular to that edge to more easily form the lithography hotspot, i.e., to increase the probability of forming a broken line hotspot. Finally, the initial lithography hotspot pattern shown in Figure 2 is transformed into the new lithography hotspot pattern shown in Figure 3. In this embodiment, the set distance is, for example, 0.050 μm, but it is not limited to this.
[0061] The difference between the new lithography hotspot pattern and the initial lithography hotspot pattern lies only in the size change of the pattern within the lithography hotspot area of the new lithography hotspot pattern, which intensifies the lithography hotspot, while the pattern outside the lithography hotspot area remains unchanged.
[0062] Figure 4 shows an initial lithography hotspot pattern for bridging provided in an embodiment of the present invention, and Figure 5 shows a new lithography hotspot pattern corresponding to Figure 4. Referring to Figure 4, the lithography hotspot type is bridging. A portion of the initial lithography hotspot pattern is selected as the lithography hotspot region with a preset size centered on the geometric center O of the lithography hotspot, as shown in the red box in Figure 4. The preset size can be determined manually, for example, based on the area required to intensify the lithography hotspot. An exemplary preset size is 0.2 μm. The lithography hotspot region can be a square centered on the geometric center O of the lithography hotspot, but it is not limited to a square; it can also be other shapes known to those skilled in the art. Then, the size of the pattern within the lithography hotspot region is changed along a direction more conducive to forming the lithography hotspot. Specifically, each edge of the pattern within the lithography hotspot region is extended outward by a preset distance in a direction perpendicular to that edge to more easily form the lithography hotspot, i.e., to increase the probability of bridging hotspot formation. Finally, the initial lithography hotspot pattern shown in Figure 4 is transformed into the new lithography hotspot pattern shown in Figure 5. In this embodiment, the set distance is, for example, 0.050 μm, but it is not limited to this.
[0063] For other types of initial lithography hotspot patterns, the same method can be used to exacerbate the lithography hotspots, that is, to make the lithography hotspots more severe by moving the pattern size, or to make the pattern that originally did not have lithography hotspots generate lithography hotspots.
[0064] In this embodiment, by changing the size of the pattern in the hot spot area of the photolithography process, the potentially non-existent hot spot of the photolithography process in step S2 is transformed into a real hot spot of the photolithography process.
[0065] In step S4, the new photolithography hotspot patterns are screened to ensure that the new photolithography hotspot patterns are not repeated.
[0066] By adjusting the specifications and changing the pattern size, multiple new photolithography hotspot patterns of different types are generated. However, there may be many identical patterns among these new photolithography hotspot patterns, or the same pattern may belong to multiple types of photolithography hotspots. In order to save space in the subsequent photolithography hotspot pattern database, the new photolithography hotspot patterns are screened in this step.
[0067] In this embodiment, the method for screening the new lithography hotspot pattern includes: determining the layout coordinates corresponding to the geometric center of the lithography hotspot in the new lithography hotspot pattern; screening the new lithography hotspot pattern according to its appearance; and / or screening the new lithography hotspot pattern according to the priority of the lithography hotspot type.
[0068] The layout coordinates (GDS coordinates) corresponding to the geometric center of the photolithography hotspot in the new photolithography hotspot pattern are determined. Each new photolithography hotspot pattern has corresponding layout coordinates.
[0069] The method for filtering new lithography hotspot patterns based on their pattern appearance includes: for multiple new lithography hotspot patterns with identical patterns, retaining the new lithography hotspot pattern with the most severe hotspot. That is, if multiple lithography hotspot patterns have the same pattern, then retain the one with the most severe hotspot, and delete the rest.
[0070] For the same new lithography hotspot pattern, there may be multiple types of hotspots as shown in Table 1. Therefore, by filtering and deduplicating, only one lithography hotspot pattern needs to be retained. The method for filtering the new lithography hotspot patterns according to the priority of the lithography hotspot type includes: for multiple new lithography hotspot patterns with the same layout coordinates but different types, retain the new lithography hotspot pattern with the highest priority. In this embodiment, the priority of the lithography hotspot type can be determined according to the actual situation and is not fixed. For example, the priority of the lithography hotspot type from largest to smallest is: broken line, bridging > one-dimensional negative EPE, one-dimensional positive EPE > two-dimensional line end negative EPE, two-dimensional line end positive EPE > two-dimensional interval end negative EPE, two-dimensional interval end positive EPE > wrapping upper hole, wrapping lower hole > pattern area.
[0071] Figures 6 and 7 show two lithography hotspot patterns of the same layout coordinates but different types. Referring to Figure 6, its lithography process type is a broken line; referring to Figure 7, its lithography process type is a one-dimensional negative EPE. Based on the priority of the lithography hotspot types, the lithography hotspot pattern shown in Figure 6 is retained, and the lithography hotspot pattern shown in Figure 7 is removed.
[0072] Multiple new photolithography hotspot patterns were screened, and the morphology of each type of photolithography hotspot pattern is unique and there are no duplicates.
[0073] In step S5, the new photolithography hotspot patterns after screening are used to form a photolithography hotspot pattern library.
[0074] In this embodiment, the method for forming a lithography hotspot pattern library from the new lithography hotspot patterns after screening includes: setting a cross mark in the lithography hotspot area with the geometric center of the lithography hotspot as the center; extracting the lithography hotspot area from the new lithography hotspot pattern as the final lithography hotspot pattern; and arranging multiple final lithography hotspot patterns in a regular manner to form the lithography hotspot pattern library.
[0075] Figure 8 shows a new lithography hotspot pattern after setting crosshairs according to an embodiment of the present invention. Referring to Figure 8, crosshairs are set within the lithography hotspot area with the geometric center of the hotspot as the center. The crosshairs can fill the entire lithography hotspot area; that is, the horizontal marks of the crosshairs extend from the left side to the right side of the lithography hotspot area, and the vertical marks extend from the upper side to the lower side of the lithography hotspot area. The crosshairs are used for subsequent pattern arrangement and positioning, as well as for generating measurement files.
[0076] Then, the hotspot area of the lithography process is extracted from the new lithography hotspot pattern as the final lithography hotspot pattern. That is, the area within the square in the pattern shown in Figure 8 is extracted as the final lithography pattern.
[0077] Subsequently, the multiple final lithography process patterns are arranged in a regular pattern to form the lithography process hotspot pattern library, resulting in the pattern shown in Figure 9. For example, multiple final lithography process patterns are arranged at a certain distance in the X and Y directions, such as a spacing of 15 μm. Alternatively, a new layout file can be generated with the lower left corner as the layout origin, and this file can be denoted as the lithography process hotspot pattern library corresponding to the layout.
[0078] It should be noted that in this embodiment, multiple layouts are imported into the initial program, resulting in photolithography hotspot graphic libraries corresponding to different layouts. In one embodiment of the present invention, multiple photolithography hotspot graphic libraries can be merged into one photolithography hotspot graphic library, forming the graphic shown in Figure 10.
[0079] In step S5, the initial program is debugged based on the graphics in the lithography process hotspot graphics library to form the final program, and the final program is used to correct the layout.
[0080] Specifically, the photolithography hotspot pattern library is imported into the initial version of the program. The initial version of the program is then used to correct the photolithography hotspot patterns. The correction process is also a process of continuous program debugging. During the continuous debugging process, the initial version of the program is continuously improved until all photolithography hotspots are resolved, and finally the final version of the program is formed, so that the final version of the program can be applied to all products.
[0081] Finally, the final version program is used to make overall corrections to all layouts. Compared with the initial program, the final version program can not only predict and correct most types of patterns, but also predict and correct photolithography hotspots.
[0082] This invention obtains as many potential lithography hotspots as possible by adjusting the initial program specifications. Then, the dimensions of the patterns within the areas containing these hotspots are resized to confirm their existence. These hotspot patterns are then compiled into a pattern library. By correcting the patterns in this library, the invention aims to predict and correct lithography hotspots for all products, covering corrections for most types of hotspots. Compared to existing technologies, this saves time and cost. Furthermore, after creating new hotspot patterns, a filtering operation removes duplicate patterns, saving space in the subsequently created hotspot pattern library and reducing the need for subsequent corrections.
[0083] In summary, the method for predicting and correcting lithography hotspots provided by this invention first imports the product layout into a preliminary program. Then, the specifications of the preliminary program are adjusted along the direction in which the lithography hotspots are formed to obtain multiple initial lithography hotspot patterns of various types. Next, using the geometric center of the lithography hotspot in the initial lithography hotspot pattern as the center, a portion of the initial lithography hotspot pattern is selected as the lithography hotspot region with a preset size. The size of the pattern within the lithography hotspot region is changed along the direction that intensifies the lithography hotspot, forming a new lithography hotspot pattern from the initial lithography hotspot pattern. Then, the new lithography hotspot patterns are screened to ensure that they are not duplicated. Finally, the screened new lithography hotspot patterns are compiled into a lithography hotspot pattern library. Based on the patterns in the lithography hotspot pattern library, the preliminary program is debugged to form the final program. This invention creates multiple lithography hotspot patterns by adjusting specifications and changing the size of the patterns, forming a lithography hotspot pattern library. An initial version of the program is used to modify the patterns in the library to create a final version. This final version is more targeted and sensitive to lithography hotspots, covering the correction of most lithography hotspots. All potential lithography hotspots in the product can be corrected, achieving the goal of predicting and correcting lithography hotspots at the OPC stage. This avoids discovering lithography hotspots only after they appear on the wafer, thus saving time and costs.
[0084] Meanwhile, the initial program is debugged by modifying the graphics in the lithography process hotspot graphics library, which is more efficient than the existing method of debugging the initial program by extracting a partial layout. The graphics types are more comprehensive and the lithography process hotspots are more targeted.
[0085] 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 in any way. Any changes or modifications made by those skilled in the art based on the above disclosure shall fall within the protection scope of the claims.
Claims
1. A method for predicting and correcting hot spots in a photolithography process, characterized in that, This includes the following steps: Importing the product layout into the initial version of the program; The specifications of the initial program are adjusted along the direction in which the photolithography hotspots are formed to obtain multiple initial photolithography hotspot patterns of various types. Using the geometric center of the photolithography hotspot in each initial hotspot pattern as the center, a portion of the initial hotspot pattern is selected as a photolithography hotspot region with a preset size. The size of the pattern within the photolithography hotspot region is changed along the direction that intensifies the photolithography hotspot, forming a new photolithography hotspot pattern from the initial hotspot pattern. The new photolithography hotspot patterns are then screened to ensure that no two new hotspot patterns are duplicated. The screened new hotspot patterns are then compiled into a photolithography hotspot pattern library. Finally, the initial program is debugged based on the patterns in the photolithography hotspot pattern library to form a final program, and the final program is used to correct the layout.
2. The method for predicting and correcting hot spots in photolithography processes according to claim 1, characterized in that, When the hot spot type of the lithography process is a broken line, the method for changing the size of the pattern in the hot spot area along the direction that aggravates the hot spot includes: shrinking each edge of the pattern in the hot spot area inward by a preset distance in a direction perpendicular to that edge; when the hot spot type of the lithography process is a bridging, the method for changing the size of the pattern in the hot spot area along the direction that aggravates the hot spot includes: extending each edge of the pattern in the hot spot area outward by a preset distance in a direction perpendicular to that edge.
3. The method for predicting and correcting hot spots in photolithography processes according to claim 1, characterized in that, The method for filtering the new lithography hotspot pattern includes: determining the layout coordinates corresponding to the geometric center of the lithography hotspot in the new lithography hotspot pattern; filtering the new lithography hotspot pattern according to its appearance; and / or filtering the new lithography hotspot pattern according to the priority of the lithography hotspot type.
4. The method for predicting and correcting hot spots in photolithography processes according to claim 3, characterized in that, The method for filtering the new lithography hotspot patterns according to their pattern appearance includes: for multiple new lithography hotspot patterns with repeated pattern appearances, retaining the new lithography hotspot pattern with the most severe lithography hotspot.
5. The method for predicting and correcting hot spots in photolithography processes according to claim 3, characterized in that, The method for filtering the new lithography hotspot patterns according to the priority of the lithography hotspot type includes: for multiple new lithography hotspot patterns with the same layout coordinates but different types, retaining the new lithography hotspot pattern with the highest priority of the lithography hotspot type.
6. The method for predicting and correcting hot spots in the photolithography process according to claim 5, wherein the priority of the hot spot types in the photolithography process from largest to smallest is: broken line, bridging > one-dimensional negative EPE, one-dimensional positive EPE > two-dimensional line end negative EPE, two-dimensional line end positive EPE > two-dimensional interval end negative EPE, two-dimensional interval end positive EPE > wrapping upper hole, wrapping lower hole > pattern area.
7. The method for predicting and correcting hot spots in photolithography processes according to claim 1, characterized in that, The method for assembling the new photolithography hotspot patterns after screening into a photolithography hotspot pattern library includes: setting a cross mark in the photolithography hotspot area with the geometric center of the photolithography hotspot as the center; extracting the photolithography hotspot area from the new photolithography hotspot pattern as the final photolithography hotspot pattern; and arranging multiple final photolithography hotspot patterns in a regular manner to form the photolithography hotspot pattern library.
8. The method for predicting and correcting hot spots in photolithography processes according to claim 1, characterized in that, Import multiple layouts of multiple products into the initial version of the program to obtain a photolithography process hotspot graphic library for multiple layouts.
9. The method for predicting and correcting hot spots in photolithography processes according to claim 8, characterized in that, Also includes: Multiple lithography process hotspot pattern libraries are merged into one lithography process hotspot pattern library.
10. The method for predicting and correcting hot spots in photolithography processes according to claim 1, characterized in that, The method for debugging the initial program to form the final program based on the graphics in the lithography process hotspot graphics library includes: importing the lithography process hotspot graphics library into the initial program, using the initial program to correct the lithography process hotspot graphics in the lithography process hotspot graphics library, and the correction process is the process of continuously debugging the initial program until all lithography process hotspots are resolved to form the final program.