Model-based data conversion
AssigneeNumerical Technologies, Inc.
InventorChristophe Pierrat
Life of this patent
Estimating the term…
Abstract
Shifters on a phase shifting mask (PSM) can be intelligently assigned their corresponding phase. Specifically, the phase of a shifter can be assigned based on simulating the contrast provided by each phase for that shifter. The higher the contrast, the better the lithographic performance of the shifter. Therefore, the phase providing the higher contrast can be selected for that shifter. To facilitate this phase assignment, a pre-shifter can be placed relative to a feature on the layout. The pre-shifter can then be divided into a plurality of shifter tiles for contrast analysis. Model-based data conversion allows for a comprehensive solution including both phase assignment as well as optical proximity correction.
Claims24
A method of providing shifters on a layout, the method comprising:
- placing a pre-shifter relative to a feature on the layout;
- dividing the pre-shifter into a plurality of shifter tiles;
- determining a first contrast and a second contrast provided by assigning a first phase and a second phase, respectively, to a shifter tile in the plurality of shifter tiles;
- selecting a phase for the shifter tile based on the step of determining;
- and
- repeating the steps of determining and selecting for remaining shifter tiles in the plurality of shifter tiles.
A computer software for generating a computer readable output regarding a photolithographic mask, the photolithographic mask used for transferring a pattern onto a wafer, the computer software comprising:
- a source code segment for identifying a feature in the pattern, the feature including a plurality of edges;
- a source code segment for placing a pre-shifter around the feature proximate to the plurality of edges;
- a source code segment for dividing the pre-shifter into a plurality of shifter tiles, the dividing based on dissection points provided by a model-based tool;
- a source code segment for determining a first contrast and a second contrast provided by assigning a first phase and a second phase, respectively, to a shifter tile in the plurality of shifter tiles;
- a source code segment for selecting whichever of the first and second phases provides the higher contrast;
- and
- a source code segment for repeating the steps of determining and selecting for a majority of the plurality of shifter tiles.
A photolithographic mask for transferring a pattern to a wafer, the pattern including a plurality of features, the photolithographic mask comprising:
- a dark field mask including shifters, each shifter having an associated phase, the shifters defined by a process comprising:
- placing a pre-shifter proximate to edges of a feature on the layout;
- dividing the pre-shifter into a plurality of shifter tiles;
- determining a first contrast and a second contrast provided by assigning a first phase and a second phase, respectively, to a shifter tile in the plurality of shifter tiles;
- selecting a phase for the shifter tile based on the step of determining;
- and
- repeating the steps of determining and selecting for remaining shifter tiles in the plurality of shifter tiles.
Dependencies are inferred from the claim text.