US 6,787,271 B2 · Design and layout of phase shifting photolithographic masks

Abstract

A method for defining a full phase layout for defining a layer of material in an integrated circuit is described. The method can be used to define, arrange, and refine phase shifters to substantially define the layer using phase shifting. Through the process, computer readable definitions of an alternating aperture, dark field phase shift mask and of a complimentary mask are generated. Masks can be made from the definitions and then used to fabricate a layer of material in an integrated circuit. The separations between phase shifters, or cuts, are designed for easy mask manufacturability while also maximizing the amount of each feature defined by the phase shifting mask. Cost functions are used to describe the relative quality of phase assignments and to select higher quality phase assignments and reduce phase conflicts.

Claims27

Dependent claims

A method for manufacturing an integrated circuit having a layer of material, the layer described by a layout, wherein substantially all of the layer of material will be defined using phase shifting, the method comprising:

identifying a plurality of features in the layout to be defined using phase shifting, each of the plurality of features comprised of a plurality of edges;
placing a plurality of shifter shapes proximate to edges of the plurality of features, wherein the plurality of features includes a first feature having a first edge and a second edge, the first edge adjoining the second edge, and wherein the plurality of shifter shapes includes a first shifter shape placed on the first edge and a second shifter shape placed on the second edge, the first shifter shape and the second shifter shape separated by a minimum distance;
assigning phase to the plurality of shifter shapes according to phase dependencies and costs to create a plurality of phase shifters;
and
refining the plurality of phase shifters.

2 more elements

identifying a plurality of features in the layout to be defined using phase shifting, each of the plurality of features comprised of a plurality of edges;
creating a plurality of phase shifters by placing, and assigning phase to, and refining a plurality of shifter shapes proximate to edges of the plurality of features, wherein die plurality of features includes a first feature having a first edge and a second edge, the first edge adjoining the second edge, and wherein the plurality of shifter shapes includes a first shifter shape placed on the first edge and a second shifter shape placed on the second edge, the first shifter shape and the second shifter shape separated by a minimum distance;
exposing radiation sensitive material to radiation according to a pattern defined using the plurality of phase shifters;
and
developing the exposed radiation sensitive material to define the layout, and forming said layer of material according to the layout.

2 more elements

A method for manufacturing an integrated circuit having a layer of material, the layer described by a layout, the method comprising:

identifying a plurality of features in the layout to be defined using phase shifting, each of the plurality of features comprised of a plurality of edges;
placing a plurality of shifter shapes proximate to edges of the plurality of features, wherein the plurality of features includes a first feature having a first edge and a second edge, the first edge adjoining the second edge, and wherein the plurality of shifter shapes includes a first shifter shape placed on the first edge and a second shifter shape placed on the second edge, the first shifter shape and the second shifter shape, the first and second shifter shapes respectively comprised of a trapezoid stacked on top of a rectangle, with the rectangular portion immediately adjacent feature edges;
assigning phase to the plurality of shifter shapes according to phase dependencies and costs to create a plurality of phase shifters;
and
refining the plurality of phase shifters.

2 more elements

Dependencies are inferred from the claim text.

Design and layout of phase shifting photolithographic masks

Life of this patent

Design and layout of phase shifting photolithographic masks

Life of this patent

Abstract

Claims27