Tools exist to identify geometrically unique portions of a pattern layout (e.g., unique clips or patches from a full chip IC design layout), each portion having a certain area of patterns. The identified unique portions are different from cach other. However, the number of unique portions determined by these tools is very large, and there is no effective mechanism to cap or otherwise control this number. Often, some of the unique portions (e.g., clips or patches) that are reported have geometry that is only slightly different, and include a large amount of redundant information from one portion to the next. The large number of unique portions determined, and the redundant information, can burden downstream computing (e.g., computational lithography) processes because the large number and/or redundant information creates a need for significant computing resources. According to embodiments of the present disclasure, systems and methods are configured for selecting an optimized, geometrically diverse subset of unique portions (e.g., clips or patches) that have a reduced number of portion counts, and yet in combination, encompass adequate patterns from the patterm layout (e.g. a design layout). The number of the selected unique portions may be up to 100 times less than the large number of portions identified by prior tools, for example. Even though significantly fewer unique portions are selected, they include enough geometric diversity, e.g., to represent the whole pattern layout of a full chip. This can significantly reduce required computing resources, and expedite downstream compating processes, among other advantages. Thus, according to an embodiment, there is provided a method for selecting an optimized, geometrically diverse set of portions (e.g., clips or patches) for a patterm (e.g., design) layout for a semiconductor wafer. The method comprises receiving a representation (e.g., an original and/or complete representation) of the pattem layout. The method comprises determining a set of representative portions of the pattern layout, where individual representative portions comprise different combinations of one or more (e.g., geometrically) unique patterns of the panern layout. As used herein, "unique patterm" refers to a patterm that is deemed different than other unique patterns in the pattern layout (design layout). A pattern is usually defined by a spatial window of interest in the layout. Pattern uniqueness can be defined by having a specific unique representation in a representation space. For example, uniqueness may be defimed by having a specific unique shape(s).arrangement(s) of features, contour(s), ete., in a representation in a spatial window of interest. A unique patten may have many instances (e.g., may repeat) across the pattern layout. A unique pattern may inclade identical or similar instances. Unique patterns may be extracted or identified from a pattern layout by using exact matching, fuzzy matching, clustering, or other algorithms or methods.Thus, as referred herein, a unique pattern may be a pattern representative of a group of patterns that exactly match, or a group of patterms that are similar, as can be identified by fuzzy matching. A set of representative portions (e.g., elips or patches) may be determined by grouping patterns that repeat across the pattem layout. A subset of the representative portions may then be selected based on the one or more unique patterns. The subset of the representative portions is.
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