Abstract: A method and apparatus for providing correction for microloading effects is described. Hybrid proximity correction techniques are used to make the problem computationally more feasible. More specifically, feature edges in a layout can be grouped into those edges, or edge segments, with a large edge separation (group B), e.g. greater than n, and those having less than that separation (group A). The group B features can then be corrected for microloading effects rapidly using rules based correction. Then both groups of edges can be corrected using model based optical proximity correction using the output of the rule based correction as the ideal, or reference, layout.

Abstract: Techniques are provided for extending the use of phase shift techniques to implementation of masks used for complex layouts in the layers of integrated circuits, beyond selected critical dimension features such as transistor gates to which such structures have been limited in the past. The method includes identifying features for which phase shifting can be applied, automatically mapping the phase shifting regions for implementation of such features, resolving phase conflicts which might occur according to a given design rule, and application of sub-resolution assist features within phase shift regions and optical proximity correction features to phase shift regions. Both opaque field phase shift masks and complementary binary masks defining interconnect structures and other types of structures that are not defined using phase shifting, necessary for completion of the layout of the layer are produced.

Abstract: Layout processing can be applied to an integrated circuit (IC) layout using a shape-based system. A shape can be defined by a set of associated edges in a specified configuration. A catalog of shapes is defined and layout processing actions are associated with the various shapes. Each layout processing action applies a specified layout modification to its associated shape. A shape-based rule system advantageously enables efficient formulation and precise application of layout modifications. Shapes/actions can be provided as defaults, can be retrieved from a remote source, or can be defined by the user. The layout processing actions can be compiled in a bias table. The bias table can include both rule-based and model-based actions, and can also include single-edge shapes for completeness. The scanning of the IC layout can be performed in order of increasing or decreasing complexity, or can be specified by the user.

Abstract: Methods and apparatuses for preparing layouts and masks that use phase shifting to enable production of subwavelength features on an integrated circuit in close (optical) proximity to other structures are described. One embodiment selects from several strategies for resolving conflicts between phase shifters used to define features and (optically) proximate structures that are being defined other than by phase shifting. One embodiment adds additional phase shifters to define the conflicting structures. Another embodiment optically corrects the shape of the phase shifters in proximity to a conflicting structure. Resulting integrated circuits can include a greater number of subwavelength features even in areas that are in close proximity to structures that were not initially identified for production using a phase shifting mask.

Abstract: Phase shifting layouts and masks with phase conflicts are described. The phase shifting layout defines light transmissive regions for use in defining selected features in a layer of material of an integrated circuit (IC). The phase shifting layout includes a phase conflict caused by two light transmissive regions that are out of phase with each other and which, without correction, would lead to the definition of an artifact in the layer of material. A corresponding mask adapted for use in conjunction with the phase shifting mask can ensure that the artifact is ultimately erased. The phase conflict is intentionally introduced into the phase shifting layout during phase assignment to permit all of the selected features to be defined using the phase shifting mask.

Abstract: A method and apparatus for performing an operation on hierarchically described integrated circuit layouts such that the original hierarchy of the layout is maintained is provided. The method comprises providing a hierarchically described layout as a first input and providing a particular set of operating criteria corresponding to the operation to be performed as a second input. The mask operation, which may include operations such as OPC and logical operations such as NOT and OR, is then performed on the layout in accordance with the particular set of operating criteria. A first program data comprising hierarchically configured correction data corresponding to the hierarchically described layout is then generated in response to the layout operation such that if the first program data were applied to the flattened layout an output comprising data representative of the result of performing the operation on the layout would be generated.

Abstract: A method extends the use of phase shift techniques to complex layouts, and includes identifying a pattern, and automatically mapping the phase shifting regions for implementation of such features. The pattern includes small features having a dimension smaller than a first particular feature size, and at least one relatively large feature, the at least one relatively large feature and another feature in the pattern having respective sides separated by a narrow space. Phase shift regions are laid out including a first set of phase shift regions to define said small features, and a second set of phase shift regions to assist definition of said side of said relatively large feature. An opaque feature is used to define the relatively large feature, and a phase shift region in the second set is a sub-resolution window inside the perimeter of the opaque feature.

Abstract: Methods and apparatuses for preparing layouts and masks that use phase shifting to enable production of subwavelength features on an integrated circuit in close (optical) proximity to other structures are described. One embodiment selects from several strategies for resolving conflicts between phase shifters used to define features and (optically) proximate structures that are being defined other than by phase shifting. One embodiment adds additional phase shifters to define the conflicting structures. Another embodiment optically corrects the shape of the phase shifters in proximity to a conflicting structure. Resulting integrated circuits can include a greater number of subwavelength features even in areas that are in close proximity to structures that were not initially identified for production using a phase shifting mask.

Abstract: Techniques are provided for extending the use of phase shift techniques to implementation of masks used for complex layouts in the layers of integrated circuits, beyond selected critical dimension features such as transistor gates to which such structures have been limited in the past. The method includes identifying features for which phase shifting can be applied, automatically mapping the phase shifting regions for implementation of such features, resolving phase conflicts which might occur according to a given design rule, and application of sub-resolution assist features within phase shift regions and optical proximity correction features to phase shift regions. In one approach, phase shift regions are laid out so that they extend around corners in a feature, and in one or more identified corners having greater process latitude, the phase shift regions are divided and assigned opposite phases in the corner.

Abstract: One embodiment of the invention provides a system for generating an instance-based representation of a set of geometrical features that comprise a layout of a circuit on a semiconductor chip. This system operates by receiving a design hierarchy specifying the layout of the circuit, wherein the design hierarchy includes a set of hierarchically organized nodes. Within this design hierarchy, a given node specifies a geometrical feature, which can be comprised of lower-level geometrical features. These lower-level geometrical features are represented by lower-level nodes that appear under the given node in the design hierarchy. Furthermore, the layout of the given node is specified by a first cell, which in turn specifies the layout of one or more nodes in the design hierarchy. For each node within the design hierarchy, the system determines how interactions with the node's siblings and/or parent, and possibly other surrounding geometries, change the layout of the node as specified by the first cell.

Abstract: Techniques are provided for extending the use of phase shift techniques to implementation of masks used for complex layouts in the layers of integrated circuits, beyond selected critical dimension features such as transistor gates to which such structures have been limited in the past. The method includes identifying features for which phase shifting can be applied, automatically mapping the phase shifting regions for implementation of such features, resolving phase conflicts which might occur according to a given design rule, and application of sub-resolution assist features within phase shift regions and optical proximity correction features to phase shift regions. Both opaque field phase shift masks and complementary binary masks defining interconnect structures and other types of structures that are not defined using phase shifting, necessary for completion of the layout of the layer are produced.

Abstract: Techniques are provided for extending the use of phase shift techniques to implementation of masks used for complex “double-T” layouts in the layers of integrated circuits, beyond selected critical dimension features such as transistor gates to which such structures have been limited in the past. The method includes identifying features, including “double-T” features, for which phase shifting can be applied, automatically mapping the phase shifting regions for implementation of such features, resolving phase conflicts which might occur according to a given design rule, and application of sub-resolution assist features within phase shift regions and optical proximity correction features to phase shift regions. Both opaque field phase shift masks and complementary binary masks defining interconnect structures and other types of structures that are not defined using phase shifting, necessary for completion of the layout of the layer are produced.

Abstract: A photolithographic mask used for defining a layer in an integrated circuit, or other work piece, where the layer comprises a pattern including a plurality of features to be implemented with phase shifting in phase shift regions is laid out including for patterns comprising high density, small dimension features, and for “full shift” patterns. The method includes identifying cutting areas for phase shift regions based on characteristics of the pattern. Next, the process cuts the phase shift regions in selected ones of the cutting areas to define phase shift windows, and assigns phase values to the phase shift windows. The phase shift values assigned comprise &phgr; and &thgr;, so that destructive interference is caused in transitions between adjacent phase shift windows having respective phase shift values of &phgr; and &thgr;. In the preferred embodiment, &phgr; is equal to approximately &thgr;+180 degrees.

Abstract: A method for producing a computer readable definition of photolithographic mask used to define a target pattern is provided. The phase shift mask patterns include phase shift windows, and the trim mask patterns include trim shapes, which have boundaries defined by such sets of line segments. For a particular pair of phase shift windows used to define a target feature in a target pattern, each of the phase shift windows in the pair can be considered to have a boundary that includes at least one line segment that abuts the target feature. Likewise, a complementary trim shape used in definition of the target feature, for example by including a transmissive region used to clear an unwanted phase transition between the particular pair of phase shift windows, includes at least one line segment that can be considered to abut the target feature.

Abstract: Mask and integrated circuit fabrication approaches are described to facilitate use of so called “full phase” masks. This facilitates use of masks where substantially all of a layout is defined using phase shifting. More specifically, exposure settings including relative dosing between the phase shift mask and the trim masks are described. Additionally, single reticle approaches for accommodating both masks are considered. In one embodiment, the phase shifting mask and the trim mask are exposed using the same exposure conditions, except for relative dosing. In another embodiment, the relative dosing between the phase and trim patterns is 1.0:r, 2.0<r<4.0. These approaches facilitate better exposure profiles for the resulting ICs and can thus improve chip yield and increase throughput by reducing the need to alter settings and/or switch reticles between exposures.

Abstract: A method and apparatus for creating a phase shifting mask and a structure mask for shrinking integrated circuit designs. One embodiment of the invention includes using a two mask process. The first mask is an opaque-field phase shift mask and the second mask is a single phase structure mask. A phase shift window is aligned with the opaque field using a phase shift overlap area on the opaque field. The phase shift mask primarily defines regions requiring phase shifting. The single phase structure mask primarily defines regions not requiring phase shifting. The single phase structure mask also prevents the erasure of the phase shifting regions and prevents the creation of undesirable artifact regions that would otherwise be created by the phase shift mask. Both masks are derived from a set of masks used in a larger minimum dimension process technology.

Abstract: One embodiment of the invention provides a system for generating trim to be used in conjunction with phase shifters during an optical lithography process for manufacturing an integrated circuit. The system operates by identifying a feature within the integrated circuit to be created by using a phase shifter to produce a region of destructive light interference on a photoresist layer. Next, the system generates the phase shifter for a first mask, while ensuring that design rules are satisfied in defining dimensions for the phase shifter. After the phase shifter is generated, the system generates trim within a second mask, that is used in conjunction with the first mask, by deriving the trim from the previously-defined dimensions of the phase shifter while ensuring that the design rules are satisfied. Note that the design rules can be satisfied by cutting and/or patching portions of the phase shifter and associated trim.

Abstract: A simulated wafer image of a physical mask and a defect-free reference image are used to generate a severity score for each defect, thereby giving a customer meaningful information to accurately assess the consequences of using a mask or repairing that mask. The defect severity score is calculated based on a number of factors relating to the changes in critical dimensions of the neighbor features to the defect. A common process window can also be used to provide objective information regarding defect printability. Certain other aspects of the mask relating to mask quality, such as line edge roughness and contact corner rounding, can also be quantified by using the simulated wafer image of the physical mask.

Abstract: One embodiment of the invention provides a method and a system for using phase shifter cutbacks to resolve conflicts between phase shifters during creation of a mask to be used in an optical lithography process for manufacturing an integrated circuit. The system works by locating a plurality of phase shifters, including a first phase shifter and a second phase shifter, on a phase shifting mask, and then identifying a conflict area wherein a conflict is likely to occur between the first phase shifter and the second phase shifter on the phase shifting mask. The system resolves this conflict by cutting back one or both of the first phase shifter and the second phase shifter, so that the first phase shifter and the second phase shifter do not interfere with each other in the conflict area.

Abstract: Phase information is incorporated into a cell-based design methodology. Standard cells have four edges: top, bottom, left, and right. The top and bottom edges have fixed phase shifters placed, e.g. 0. A given cell C will have a phase set created with two versions: 0-180 (left-right) as well as 180-0. Alternatively, the same phase set: 0-0 and 180-180 could be created for a cell. The phase sets are selected based on the ability to phase shift the features within the cell C. By creating a phase set for most of the cells of a cell library, standard cell placement and routing techniques can be used and phase can then be quickly assigned using a simple ripple technique. This ensures a phase compliant design upfront for the standard cell areas.