Method for OPC data collection and OPC modeling method
By optically simulating the OPC test mask and classifying and marking the test points, the accuracy and efficiency issues of OPC data collection are solved, and more accurate OPC model calibration is achieved.
Patent Information
- Application Number
- CN202510973509.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-15
- Publication Date
- 2025-09-16
AI Technical Summary
In the prior art, there is a large difference between the layout data of the OPC test mask pattern and the OPC data after exposure, resulting in low accuracy of the OPC model and increased manual judgment time, making it difficult to collect OPC data quickly and accurately.
Before the OPC test mask is exposed, the first dimension data of each test point is obtained through optical simulation and compared with the preset dimensions. The test points are classified and marked, and a measurement program is established to collect OPC data, reducing manual judgment time and improving data collection accuracy.
The accuracy and efficiency of OPC data collection are improved, the subsequent manual judgment time is reduced, and the accuracy of measurement data and model calibration effect are ensured.
Smart Images
Figure CN120652730A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of integrated circuit manufacturing, and in particular to a method for collecting OPC data and an OPC modeling method. Background Art
[0002] In the photolithography process, the graphic structure corresponding to the layout on the mask will be projected into the photoresist through the exposure system and form the corresponding graphic structure in the photoresist. However, due to optical reasons in the exposure process (such as diffraction effect) or the photochemical reaction of the photoresist, there is a deviation between the graphic structure formed in the photoresist and the graphic structure on the mask. This deviation requires the layout on the mask to be modified in advance through OPC (Optical Proximity Correction). When the mask corrected by OPC is used for exposure, the graphic structure formed in the photoresist will be consistent with the designed graphic structure and meet the process production requirements.
[0003] Currently, before performing OPC, an OPC model corresponding to the reticle pattern must be established. Building this model requires acquiring the layout data from the OPC test reticle. Therefore, quickly and accurately acquiring (collecting) a large amount of layout data from the OPC test reticle is key to building a high-precision OPC model. Summary of the Invention
[0004] The object of the present invention is to provide a method for OPC data collection and an OPC modeling method for quickly and accurately establishing an OPC model.
[0005] To solve the above technical problems, the present invention provides a method for collecting OPC data, comprising:
[0006] Performing optical simulation on the OPC test mask pattern and obtaining first size data of each test point after the optical simulation;
[0007] Compare the first size data of each test point with the corresponding preset size,
[0008] The test points of the first range of the preset size with the first size data are used as first-type test points, and the first size data are used as target sizes of the first-type test points for establishing a measurement program to collect OPC data.
[0009] The test points whose first dimension data exceeds the first range of the preset dimension are regarded as the second type of test points, the second type of test points are marked, and the second dimension data obtained from the first dimension data and the preset dimension are used as the target dimension of the second type of test points for establishing a measurement program to collect OPC data.
[0010] Optionally, after performing optical simulation on the OPC test mask pattern, the EDA software that performs the optical simulation obtains the size data of each test point after the optical simulation as the first size data.
[0011] Optionally, the preset size of each test point includes size data on the layout of the OPC test mask or a specification size corresponding to the OPC test mask after exposure.
[0012] Optionally, the preset size of each test point is a size obtained by integrating the size data on the layout of the OPC test mask and the corresponding specification size after exposure.
[0013] Optionally, the first range of the preset size of the test point is a specification range when the test point is designed.
[0014] Optionally, a second type of test point whose first size data exceeds a second range or whose size data does not exist after optical simulation is used as a third type of test point, the second range is larger than the first range, and the target size of the third type of test point is set to a null value.
[0015] Optionally, the second-category test points are marked as the first category, and the second-category test points other than the third category test points are marked as the second category.
[0016] Optionally, the step of obtaining the second size data of the second type of test points further includes:
[0017] The second size data=the first size data*the first weight+the preset size*the second weight, wherein the first weight+the second weight=1.
[0018] Optionally, the first weight=the second weight=0.5.
[0019] According to another aspect of the present invention, an OPC modeling method is also provided, comprising:
[0020] Performing optical simulation on the OPC test mask pattern, and obtaining target sizes of the first type of test points and the second type of test points using the method for OPC data collection according to any one of claims 1 to 9;
[0021] Establishing a measurement program for an OPC test mask pattern based on target sizes of the first and second test points, and marking the second test points therein;
[0022] exposing the OPC test mask pattern, performing wafer measurement according to the measurement program to collect OPC data, and tracking the OPC data of the second type of test points;
[0023] Based on the collected OPC data, OPC modeling is performed.
[0024] In summary, the present invention provides a method for OPC data collection and an OPC modeling method, the data collection method including: performing optical simulation on the OPC test mask pattern, and obtaining first size data of each test point after the optical simulation; comparing the first size data of each test point with the corresponding preset size, treating the test points whose first size data are within the first range of the preset size as first-category test points, using the first size data as the target size of the first-category test points for establishing a measurement program to collect OPC data, treating the test points whose first size data exceed the first range of the preset size as second-category test points, marking the second-category test points, and using the second size data obtained from the first size data and the preset size as the target size of the second-category test points for establishing a measurement program to collect OPC data. Before exposing the OPC test mask, the present invention performs optical simulation on the OPC test mask pattern to obtain first dimensional data of each test point after simulation, compares the first dimensional data of each test point with the corresponding preset size, classifies each test point (similar to screening) and performs corresponding processing (performs corresponding marking and data processing), and establishes a corresponding measurement program based on the dimensional data of each test point after optical simulation. The OPC data collected by the measurement program after the OPC test mask is exposed is more accurate, ensuring a good measurement data collection effect, and can be easily tracked in subsequent processes, reducing the time for subsequent manual judgment, thereby obtaining a more accurate model calibration effect. BRIEF DESCRIPTION OF THE DRAWINGS
[0025] Those skilled in the art should understand that the drawings are provided for a better understanding of the present invention, but do not constitute any limitation on the scope of the present invention.
[0026] Figure 1 A method for collecting OPC data is provided for an embodiment of the present application;
[0027] Figure 2 A schematic diagram for classifying test points provided for this application;
[0028] Figure 3A 、 Figure 3B and Figure 3C Schematic diagram of three types of test points provided for this embodiment;
[0029] Figure 4 Flowchart of the OPC modeling method provided in an embodiment of the present application.
[0030] In the accompanying drawings: 11 - first mask pattern; 12 - second mask pattern; 13 - first simulation pattern; 14 - second simulation pattern. DETAILED DESCRIPTION
[0031] As described in the background art, the steps for collecting OPC data for an OPC test mask pattern are typically as follows: first, the OPC test mask pattern is exposed, and then OPC data is collected from the exposed pattern. Due to the large amount of OPC data to be collected, manual data collection is not feasible. Before automatically collecting OPC data, a test program for automatically collecting data must be established. This measurement program can be generated from the layout data (i.e., the mask data) of the OPC test mask pattern and automatically capture OPC data from the exposed pattern. However, in practice, due to the optical proximity effect, there is often a significant difference between the layout data of the OPC test mask pattern and the OPC data after exposure. This makes the OPC data captured using the above test program inaccurate or even fails to be captured. This not only affects the accuracy of the subsequently established OPC model, but also may increase the time required for subsequent manual judgment.
[0032] To this end, the present application provides a method for OPC data collection and an OPC modeling method. Before exposing the OPC test mask, optical simulation is performed on the OPC test mask pattern to obtain the first size data of each test point after simulation, the first size data of each test point is compared with the corresponding preset size, each test point is classified (similar to screening) and processed accordingly (corresponding marking and data processing are performed), and a corresponding measurement program is established based on the size data of each test point after optical simulation, and the OPC data collected by the measurement program after the OPC test mask is exposed is made more accurate, thereby ensuring a good measurement data collection effect, and can be easily tracked in subsequent processes, reducing the time for subsequent manual judgment, and thus obtaining a more accurate model calibration effect.
[0033] To make the objects, advantages, and features of the present invention more clearly apparent, the present invention is further described below in conjunction with 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. They are only used to conveniently and clearly assist in illustrating the purposes of the embodiments of the present invention. In addition, the structures shown in the drawings are often part of the actual structure. In particular, different drawings may need to illustrate different focuses and sometimes use different scales.
[0034] As used in the present invention, the singular forms "a", "an", and "the" include plural objects, the term "or" is generally used to include the meaning of "and / or", the term "several" is generally used to include the meaning of "at least one", and the term "at least two" is generally used to include the meaning of "two or more". In addition, the terms "first", "second", and "third" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features specified as "first", "second", and "third" may explicitly or implicitly include one or at least two of the features, unless the content clearly indicates otherwise.
[0035] An embodiment of the present application provides a method 100 for collecting OPC data.
[0036] Figure 1 This is a flowchart of a method for collecting OPC data provided by an embodiment of the present application.
[0037] like Figure 1 As shown, the method for collecting OPC data provided by this embodiment includes the following steps:
[0038] S110: performing optical simulation on the OPC test mask pattern, and obtaining first size data of each test point after the optical simulation;
[0039] S120: Compare the first dimension data of each test point with the corresponding preset dimension, and regard the test point whose first dimension data is within the first range of the preset dimension as a first type of test point, and use the first dimension data as the target dimension of the first type of test point for establishing a wafer measurement program, and regard the test point whose first dimension data exceeds the first range of the preset dimension as a second type of test point, mark the second type of test point, and use the second dimension data obtained from the first dimension data and the preset dimension as the target dimension of the second type of test point for establishing a wafer measurement program.
[0040] First, step S110 is executed to perform optical simulation on the OPC test mask pattern and obtain first size data of each test point after the optical simulation.
[0041] As mentioned above, compared to directly using the layout data of the OPC test mask pattern to establish a measurement program, the present application first uses EDA simulation software to perform optical simulation on the OPC test mask pattern before exposing the OPC test mask (or establishing a measurement program), obtains the dimensional data of each test point after the optical simulation (i.e., first dimensional data), and establishes a corresponding measurement program based on the dimensional data of each test point after the optical simulation, thereby reducing the success rate and accuracy of automatically capturing the OPC data collected after exposure using the measurement program.
[0042] The first size data of each test point of the OPC test mask pattern after optical simulation can be directly obtained from EDA simulation software.
[0043] Next, step S0120 is executed to compare the first dimension data of each test point with the corresponding preset dimension, and the test points whose first dimension data is within the first range of the preset dimension are regarded as first-category test points. The first dimension data is used as the target dimension of the first-category test points for establishing a wafer measurement program. The test points whose first dimension data exceeds the first range of the preset dimension are regarded as second-category test points, and the second-category test points are marked. The second dimension data obtained from the first dimension data and the preset dimension is used as the target dimension of the second-category test points for establishing a wafer measurement program.
[0044] It is understood that different test points have different preset sizes. In some examples, each preset size may be the size of each test point on the layout of the OPC test mask pattern, that is, the mask size. In other examples, each preset size may be the specification size of each test point on the OPC test mask pattern after exposure. In some examples, each preset size may also be a size calculated from the mask size of each test point and the corresponding specification size after exposure, so that the preset size can take into account both the mask size and the specification size. In other examples, the preset size of some test points may be the mask size on the layout, while the preset size of the remaining test points may be the specification size after exposure.
[0045] It should be noted that optical simulation is not equivalent to actual wafer exposure, and the first dimension data obtained from optical simulation does not represent the dimensions of the OPC test mask pattern after exposure, nor can such first dimension data be directly used to establish an OPC model. Therefore, before the OPC test mask is exposed and a measurement program is established for collecting OPC data, the first dimension data obtained is classified (screened) and processed accordingly (e.g., by corresponding marking and data processing, etc.) for each test point according to a preset dimension. This facilitates the establishment of a measurement program for collecting OPC data, and enables the measurement program to capture the dimension data of the OPC test mask after exposure as accurately as possible, ensuring good measurement data collection results, thereby achieving more accurate model calibration results, and distinguishing and marking test points that may be at risk for easy subsequent tracking. For example, the first dimension data of each test point can be first compared with the corresponding preset dimension, and the confidence (reliability) of the simulation result of each test point can be determined based on this, and each test point can be classified, and then different processing can be performed on each type of test point.
[0046] Figure 2 This is a schematic diagram of the classification of test points provided by this application. Figure 2 As shown, the test points with first dimension data within the first range of the preset size are taken as the first type of test points, and the first dimension data are used as the target size (measurement parameter) of the first type of test points to establish a wafer measurement program. Among them, the above-mentioned first range can be the same as or close to the preset range of the test point, that is, the test points with the difference between the dimension data after simulation and the dimension data before simulation (on the OPC test mask) within the preset range are taken as the first type of test points, and the dimension data after simulation is used as the basis (target size) for the test points when establishing the measurement program. In other words, the confidence level of the simulation results of the first type of test points is higher, and the simulation results of the first type of test points can be directly used as a reference for measuring the test points after wafer exposure. It is understandable that in the subsequent measurement process after the OPC test mask is exposed, if the measurement parameters of each test point in the measurement program are not set reasonably, the difference between the measurement parameters and the actual dimension data is too large, which will seriously affect the accuracy of the captured size and will also take longer measurement time.
[0047] Please continue to refer to Figure 2 Test points whose first dimension data exceeds the first range of preset dimensions are designated as second-category test points. These second-category test points are then marked, and second-category dimension data derived from the first dimension data and the preset dimensions is used as the target dimension for establishing a measurement program for these second-category test points. In other words, the confidence level of the simulation results for these second-category test points is low, and they cannot be directly used as a reference for measurement of these test points after exposure on the OPC test mask. However, these simulation results can be used as a partial or indirect reference.
[0048] The present application further refines the second category of test points, designating those whose first dimension data exceeds the second range or whose dimension data does not exist after optical simulation as third category test points. The remaining second category test points (i.e., those that exceed the first range but fall within the second range) remain unchanged, and the second and third category test points are marked and processed differently. The second range is larger than the first range, and the first dimension data of the (subdivided) second category test points falls between the first and second ranges of the preset dimensions, indicating that the pattern variation of the second category test points after simulation exceeds the standard but has not reached a particularly severe level. Therefore, the second category test points can be marked as first category, indicating that they require attention during subsequent OPC test mask post-exposure measurement and post-measurement, and can be marked in yellow, for example. The second category test points use the second dimension data as the target dimension for subsequent measurement program creation. The second dimension data = first dimension data * first weight + preset dimension * second weight, where both the first weight and the second weight are between 0 and 1, and the first weight + the second weight = 1. The first and second weights can be assigned based on experience or historical data. For example, both the first and second weights can be set to 0.5. If the simulated dimensional data for a test point falls outside the second range of the preset dimensions, it is essentially the same as if no simulated dimensional data for that test point existed. In other words, the simulation results for the third type of test point have no reference at all. Therefore, the third type of test point can be marked as the second type, indicating that it requires special attention during and after subsequent OPC test mask measurement after exposure. For example, the mark can be colored red, and the target dimension of the third type of test point can be set to a null value for use in establishing a measurement program.
[0049] Of course, in other examples of the present application, the second category of test points may be further subdivided into more categories according to specific circumstances, for example, all test points may be divided into first to fourth categories of test points.
[0050] In some examples, some or all of the second-category test points and / or third-category test points may be manually retested or confirmed in the subsequent full process depending on the situation. For example, after applying the measurement program to collect OPC data, the OPC data of some or all of the second-category test points and / or third-category test points may be manually collected or confirmed. For example, after establishing the OPC model, the situation of some or all of the second-category test points and / or third-category test points may be manually confirmed.
[0051] Figure 3A 、 Figure 3B and Figure 3C Schematic diagram of three types of test points provided in this embodiment. Figure 3AAs shown, the spacing distance between the first mask pattern 11 and the second mask pattern 12 circled by the dotted frame is a preset size, the first simulation pattern 13 corresponds to the first mask pattern 11, and the second simulation pattern 14 corresponds to the second mask pattern 12. The first simulation pattern 13 and the second simulation pattern 14 are deformed relative to their respective mask patterns. The spacing distance between the first simulation pattern 13 and the second simulation pattern 14 is the first size data. The preset size is 45 nanometers, the first range of the preset size is 45±10 nanometers, and the first size data is 40 nanometers. Therefore, the spacing distance between the first simulation pattern 13 and the second simulation pattern 14 can be a first type of test point, and 40 nanometers can be used as the target size for establishing a measurement program for this test point. Figure 3B As shown, the first simulation pattern 13 and the second simulation pattern 14 are both greatly deformed relative to their respective mask patterns. The spacing between the first simulation pattern 13 and the second simulation pattern 14 is the first dimension data. The preset dimension is 45 nanometers, the first range of the preset dimension is 45±10 nanometers, and the first dimension data is 8 nanometers, which is outside the range of 35 to 55 nanometers. Therefore, the spacing between the first simulation pattern 13 and the second simulation pattern 14 can be a second type of test point. The second type of test point is marked in yellow, and 26 nanometers (i.e., 8 / 2+45 / 2) is used as the target dimension for establishing the measurement program for the test point. Figure 3C As shown, the first simulation graphic 13 and the second simulation graphic 14 are severely deformed, resulting in a direct connection between the two. The spacing distance between the first simulation graphic 13 and the second simulation graphic 14 cannot be measured at all. Therefore, the spacing distance between the first simulation graphic 13 and the second simulation graphic 14 can be a third-type test point. The third-type test point is marked in red, and the target size of the test point is set to a null value.
[0052] The embodiment of the present application also provides an OPC modeling method 400 .
[0053] Figure 4 This is a flowchart of the OPC modeling method 400 provided in an embodiment of the present application.
[0054] like Figure 4 As shown, the OPC modeling method provided in this embodiment includes:
[0055] S410: performing optical simulation on the OPC test mask pattern, and obtaining target sizes of the first type of test points and the second type of test points using the above-mentioned method for collecting OPC data;
[0056] S420: establishing a measurement program for an OPC test mask pattern based on target sizes of the first and second test points, and marking the second test points therein;
[0057] S430: exposing the OPC test mask pattern, performing wafer measurement according to the measurement program to collect OPC data, and tracking the OPC data of the second type of test points;
[0058] S440: Perform OPC modeling based on the collected OPC data.
[0059] In step S410, before exposing the OPC test mask pattern, the OPC test mask pattern is optically simulated. Based on the results of the optical simulation, each test point is divided into a first type of test point and a second type of test point. The first type of test point and the second type of test point are obtained for establishing the target size of the measurement program, and the second test point is marked. The above specific steps can be referred to the aforementioned embodiment and will not be repeated here.
[0060] In step S420 , a measurement procedure of an OPC test mask pattern is established based on target sizes of the first type of test points and the second type of test points, and the second type of test points are marked.
[0061] In step S430 , the OPC test mask pattern is exposed, wafer measurement is performed according to the measurement program to collect OPC data, and the OPC data of the second type of test points is tracked, that is, the collected OPC data of the second type of test points is retested or confirmed.
[0062] In summary, the present invention provides a method for OPC data collection and an OPC modeling method, the data collection method including: performing optical simulation on the OPC test mask pattern, and obtaining first size data of each test point after the optical simulation; comparing the first size data of each test point with the corresponding preset size, taking the test point whose first size data is within the first range of the preset size as a first type of test point, using the first size data as the target size of the first type of test point for establishing a wafer measurement program, taking the test point whose first size data exceeds the first range of the preset size as a second type of test point, marking the second type of test point, and using the second size data obtained from the first size data and the preset size as the target size of the second type of test point for establishing a wafer measurement program. Before exposing the OPC test mask, the present invention performs optical simulation on the OPC test mask pattern to obtain the first size data of each test point after simulation, compares the first size data of each test point with the corresponding preset size, classifies each test point (similar to screening) and performs corresponding processing (performing corresponding marking and data processing), and establishes a corresponding measurement program based on the size data of each test point after optical simulation. The OPC data collected by the measurement program after the OPC test mask is exposed is more accurate, ensuring a good measurement data collection effect, and can be easily tracked in subsequent processes, reducing the time for subsequent manual judgment, thereby achieving a more accurate model calibration effect.
[0063] The above description is only a description of the preferred embodiments of the present invention and does not limit the scope of the present invention. Any changes and modifications made by ordinary technicians in the field of the present invention based on the above disclosure shall fall within the scope of protection of the claims.
Claims
1. A method for OPC data collection, characterized in that, include: Performing optical simulation on the OPC test mask pattern and obtaining first size data of each test point after the optical simulation; Compare the first size data of each test point with the corresponding preset size, The test points of the first range of the preset size with the first size data are used as first-type test points, and the first size data are used as target sizes of the first-type test points for establishing a measurement program to collect OPC data. The test points whose first dimension data exceeds the first range of the preset dimension are regarded as the second type of test points, the second type of test points are marked, and the second dimension data obtained from the first dimension data and the preset dimension are used as the target dimension of the second type of test points for establishing a measurement program to collect OPC data.
2. The method for OPC data collection according to claim 1, characterized in that After optical simulation is performed on the OPC test mask pattern, the size data of each test point after the optical simulation is obtained by the EDA software that performs the optical simulation as the first size data.
3. The method for OPC data collection according to claim 1, characterized in that: The preset size of each test point includes the size data on the layout of the OPC test mask or the specification size corresponding to the OPC test mask after exposure.
4. The method for OPC data collection according to claim 1, characterized in that: The preset size of each test point is a size obtained by integrating the size data on the layout of the OPC test mask and the corresponding specification size after exposure.
5. The method for OPC data collection according to claim 1, characterized in that: The first range of the preset size of the test point is the specification range when the test point is designed.
6. The method for OPC data collection according to claim 1, characterized in that: The second type of test points whose first size data exceeds the second range or whose size data does not exist after optical simulation are used as third type of test points, the second range is larger than the first range, and the target size of the third type of test points is set to a null value.
7. The method for OPC data collection according to claim 6, characterized in that: The second-category test points are marked as the first category, and the second-category test points other than the third-category test points are marked as the second category.
8. The method for OPC data collection according to claim 1, characterized in that: The step of obtaining the second size data of the second type of test points further includes: The second size data=the first size data*the first weight+the preset size*the second weight, wherein the first weight+the second weight=1.
9. The method for OPC data collection according to claim 8, characterized in that: The first weight=the second weight=0.
5.
10. An OPC modeling method, characterized in that: include: Performing optical simulation on the OPC test mask pattern, and obtaining target sizes of the first type of test points and the second type of test points using the method for OPC data collection according to any one of claims 1 to 9; Establishing a measurement program for an OPC test mask pattern based on target sizes of the first and second test points, and marking the second test points therein; exposing the OPC test mask pattern, performing wafer measurement according to the measurement program to collect OPC data, and tracking the OPC data of the second type of test points; Based on the collected OPC data, OPC modeling is performed.