Mentor Graphics Corporation

Other

Emile Y Sahouria

Nicolas Bailey Cobb

Laurence W Grodd

Weidong Zhang

Leigh C Anderson

Siqiong You

George P Lippincott

Steffen Schulze

Alexander Tritchkov

Patrick Joseph LaCour

Le Hong

Jea-Woo Park

Petr E Glotov

Yuanfang Hu

A method and apparatus for translating a hierarchical IC layout file into a format that can be used by a mask writer that accepts files having a limited hierarchy. Cover cells of the original IC layout file or a modified file are designated, and the hierarchical file is redefined to include only those designated cover cells. Non-designated cover cells and other geometric data are flattened into the designated cover cells. The hierarchy of the modified file is then redefined to be less than or equal to the hierarchy limit of the mask writing tool.

Mask creation with hierarchy management using cover cells

Techniques for reducing the number of shots required by a radiation beam writing tool to write a pattern, such as fractured layout design, onto a substrate. One or more apertures are employed by a radiation beam writing tool to write a desired pattern onto a substrate using L-shaped images, T-shaped images, or some combination of both. By reducing the number of shots required to write a pattern onto a substrate, various implementations of the invention may reduce the write time and/or write complexity of the write process.

Generalization of shot definitions for mask and wafer writing tools

Aspects of the invention relate to techniques for mask rule checking based on curvature information. The curvature information comprises convex curvature information and concave curvature information. The convex curvature information for a vertex of a mask feature may comprise a convex curvature value derived based on the size of a circle that passes through the vertex, is tangent to an edge and does not cross any other edges. The concave curvature information for the vertex may comprise a concave curvature value derived based on the size of a circle that is tangent to two edges that form the vertex and does not cross any other edges, and of which distance from the vertex measured from the nearest point is no more than a predetermined number. The generated curvature information is compared with threshold curvature information to determine mask rule violations.

Mask rule checking based on curvature

Aspects of the invention relate to techniques for integrating optical proximity correction and mask data preparation. First mask writer instructions for a layout design are simulated to generate a mask contour. Based on the generated mask contour, first layout data for the layout design are adjusted for optical proximity correction to generate second layout data. Using the generated second layout data as mask target, the first mask writer instructions are adjusted to generate second mask writer instructions. The above process may be iterated until an end condition is met.

Integration of optical proximity correction and mask data preparation

A method for separating features in a target layout into different mask layouts for use in a photolithographic process. Features of a target layer are searched for features having a predefined shape. In one embodiment, portions of the feature having the predefined shape divided into two or more sub-features and at least one sub-feature are not considered when separating the features into two or more mask layouts. In another embodiment, features having a predefined shape are cut to form two or more sub-features and all features and sub-features are considered when separating the features of the target layout into the two or more mask layouts.

IC layout parsing for multiple masks

Separation directives for integrated circuit layout design data are formed based upon one or more printing feasibility analyses performed on the layout design data. At least one printing feasibility analysis is performed on layout design data to identify portions of the design that may not be correctly formed or 'printed' during a photolithographic process. The geometric element edges involved in a potential printing defect are then identified as edges to be formed using separate masks. Further, separation directives may be created to specifically designate the identified edges as edges to be formed using separate masks in a photolithographic manufacturing process.

Forming separation directives using a printing feasibility analysis

Branching of the data-flow in a mask data preparation processes is described herein. In various implementations, the output stream from a first mask data processing operation is branched. Subsequently, the branched output stream may be connected to the input stream of a first independent mask data preparation operation and a second independent mask data preparation operation. This provides that the first and the second independent mask data preparation operations may operate in parallel. Furthermore, this provides that the first and the second independent mask data preparation operations may operate upon discrete 'portions' of the data processed by the first mask data preparation operation.

Data flow branching in mask data preparation

A method of parsing integrated circuit layout design data. According to some implementations, the segment boundaries are designated by first identifying data in the integrated circuit layout design data that matches a cell record start value. Next, the subsequent data is parsed, until a threshold amount of subsequent data has been parsed without identifying another cell record start value. When the threshold amount of subsequent data has been parsed without identifying another cell record start value, the next data in the integrated circuit layout design data matching a cell record start value is designated as a segment boundary. Integrated circuit layout design data can be segmented sequentially, or by using dyadic division. Once the integrated circuit layout design data has been broken up into segments, the segments can be provided to a parallel processing computing system for parsing in parallel.

Segmenting integrated circuit layout design files using speculative parsing

Methods for jointly calibrating etch and exposure mask process models from etch only data are described. Initially, an etch model and an exposure model may be identified. Subsequently, a combined etch/exposure model may be generated based upon the etch model and the exposure model. Following which, a global optimization process may be performed to calibrate the combined etch/exposure model based upon measured data representing the etch and the exposure effects. With some implementations, the global optimization process is based in part upon a cost function representing the norm of the difference between the simulated mask contours and the measured mask contours. Furthermore, in some implementations, the optimization variable set is the union of the parameter sets corresponding to the etch model and the exposure model individually. Further still, with various implementations, the optimization of based upon the etch parameter set is 'nested' inside an optimization of the exposure parameter set, or, vice versa.

Mask model calibration technologies involving etch effect and exposure effect

Techniques are disclosed for determining if the decomposition of layout design data is feasible, and for optimizing the segmentation of polygons in decomposable layout design data. Layout design data is analyzed to identify the edges of polygons that should be imaged by separate lithographic masks. In addition, proposed cut paths are generated to cut the polygons in the layout design data into a plurality of polygon segments. Once the separated edges and cut paths have been selected, a conflict graph is constructed that reflects these relationships. Next, a dual of the conflict graph is constructed. This dual graph will have a corresponding separation dual graph edge for each separated polygon edge pair in the layout design data. The dual graph also will have a corresponding cut path dual graph edge for each proposed cut path generated for the layout design data. After the dual graph has been constructed, it is analyzed to determine which of the proposed cut paths should be kept and which should be discarded. The layout design data is then modified to include the cut paths corresponding to the selected cut path dual graph edges. Alternately or additionally, separate sets of layout design data may be decomposed from original layout design data using the selected cut paths.

Use of graphs to decompose layout design data

A method for preparing data to create two or more masks required to print a desired feature pattern with a multiple mask technique. In one embodiment of the invention, a target feature pattern is separated into two or more groups or data layers with a coloring algorithm. Coloring conflicts or adjacent features that are within a predetermined distance of each other and are assigned to the same group or data layer are identified. Cutting boxes are added to a feature to divide a feature into two or more smaller features. A coloring algorithm is re-applied to the layout including the cutting boxes to assign the features into different groups or data layers. Data in each group or data layer is used to define a mask to print the target feature pattern.

Data preparation for multiple mask printing

Layout correction is accomplished using a forward mapping technique. Forward mapping refers to mapping of fragments from a reticle layout to a target layout, while backward mapping refers to mapping of fragments from the target layout to the reticle layout. Forward mapping provides a technique for making an unambiguous mapping for each reticle fragment to a corresponding target layout fragment. The mapping does not necessarily provide a one-to-one correspondence between reticle fragments and target layout fragments. That is, multiple reticle layout fragments can map to a single target layout fragment. An edge placement error for the target layout fragments is used to make positioning corrections for the corresponding reticle fragment(s). Edge placement error can be determined, for example, with a simulation process that simulates a manufacturing process using the reticles.

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Sunnyvale, CA, United States of America

Emile Y Sahouria