US 2003/0159126 A1Published application

Phase-shift lithography mapping method and apparatus

AssigneeSynopsys, Inc.

InventorJeffrey P. Mayhew

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Abstract

For phase-shifting microlithography, a method of assigning phase to a set of shifter polygons in a mask layer separated by a set of target features includes assigning a first phase to a first shifter polygon, identifying a set of target features that touch the first shifter polygon, and assigning a second phase to all shifter polygons in the set that touch the set of target features in contact with the first shifter polygon. The set of shifter polygons and the set of target features are separated into aggregates that are spatially isolated from each other such that the phase assignment in one aggregate does not affect the phase assignments in other aggregates. In one embodiment, the first shifter polygon in each aggregate is selected by merging the set of shifter polygons and set of target features into a large polygon, marking a vertex of the large polygon, checking the vertex to make sure it only touches one shifter polygon, and selecting the single shifter polygon touching the vertex as the first shifter polygon.

Claims2

Dependent claims

A method implemented in a computer for assigning phases to a plurality P1 of light shifter polygons of a photolithographic mask through which light is to be transmitted to photolithographically pattern an area on a substrate, wherein the mask has a plurality P2 of dark target features which are less transmissive to the light than the light shifter polygons, the method comprising:

adding plurality P1 to a group of unassigned shifter polygons;
adding plurality P2 to a group of unused target features;
initializing a first output layer for shifter polygons of a first phase;
initializing a second output layer for shifter polygons of a second phase;
initializing a first derived layer for a current set of shifter polygons;
initializing a second derived layer for a current set of target features;
initializing a third derived layer for a next set of shifter polygons;
adding at least one shifter polygon from the group of unassigned shifter polygons to the first derived layer;
adding at least one target feature from the group of unused target features to the second derived layer, wherein the at least one target feature touches a shifter polygon in the first derived layer;
removing the shifter polygon in the first derived layer from the group of unused shifter polygons;
and
adding at least one shifter polygon from the group of unused shifter polygons to the third derived layer, wherein the at least one shifter polygon added to the third derived layer touches the at least one target feature in the second derived layer.

9 more elements

Dependencies are inferred from the claim text.