Method and apparatus for allowing phase conflicts in phase shifting mask and chromeless phase edges

A phase shifting mask for a portion of an integrated circuit (IC) layout comprising a plurality of features, the phase shifting mask comprising a plurality of light transmissive regions in an opaque field, each light transmissive region in the plurality of light transmissive regions permitting passage of light of a first wavelength at either a first phase or a second phase, and wherein the plurality of light transmissive regions includes a first light transmissive region and a second light transmissive region such that

• the plurality of light transmissive regions define the plurality of features in the IC layout;
• the first light transmissive region permits the passage of light at the first phase and the second light transmissive region permits the passage of light at the second phase;
• the first light transmissive region and the second light transmissive region have a shared boundary so as to cause destructive interference that would produce an artifact in a layer of material;
• and
• wherein a binary mask designed for use in conjunction with the phase shifting mask will prevent the artifact from remaining in a resultant integrated circuit.

A dark field mask having phase areas for defining at least a portion of an integrated circuit (IC) layout, the phase areas being defined using the following process:

• defining phase regions in the dark field mask for use in defining structures of the IC layout;
• identifying a conflict preventing assignment of phase to the phase regions;
• inserting at least one false phase area directly abutting another phase area in the dark field mask to resolve the conflict;
• defining a corresponding trim mask to remove artifacts created by use of the dark field mask having the at least one false phase area.

An electromagnetic waveform, the electromagnetic waveform comprising a computer program for producing phase shifting layout data from a portion of an integrated circuit (IC) layout, the computer program further comprising:

• a first set of instructions for identifying a feature in the IC layout for definition with a phase shifting layout using a computer;
• a second set of instructions for generating the phase shifting layout data using the IC layout, the phase shifting layout data defining phase shifting areas in an opaque field for defining the feature in the material using a computer, the phase shifting layout adapted to be used in conjunction with a second layout data, the second layout data defining other structure in the material, and preventing erasure of the feature;
• a third set of instructions for determining using a computer if a conflict exists when assigning phase to phase shifting areas in the phase shifting layout data;
• and
• a fourth set of modifying the phase shifting layout data to resolve the conflict by inserting at least one chromeless phase transition in a phase shifting area of the phase shifting layout data.

An apparatus for defining a dark field mask having phase areas for at least a portion of an integrated circuit (IC) layout, the apparatus comprising:

• means for defining phase regions in the dark field mask for use in defining structures of the IC layout;
• means for identifying a conflict preventing assignment of phase to the phase regions;
• means for inserting at least one false phase area directly abutting another phase area in the dark field mask to resolve the conflict;
• means for defining a corresponding trim mask to remove artifacts created by use of the dark field mask having the at least one false phase area.

A method for producing phase shifting layout data from a portion of an integrated circuit (IC) layout, the method comprising:

• identifying a feature in the IC layout for definition with a phase shifting layout using a computer;
• generating the phase shifting layout data using the IC layout, the phase shifting layout data defining phase shifting areas in an opaque field for defining the feature in the material using a computer, the phase shifting layout adapted to be used in conjunction with a second layout data, the second layout data defining other structure in the material, and preventing erasure of the feature, and wherein there is a chromeless phase transition in the phase shifting layout data between a first and a second phase shifting area in the phase shifting layout data;
• and
• assigning phase to phase shifting areas in the phase shifting layout data while allowing phase assignment conflicts between the first and second phase shifting areas.