Method of design and fabrication of integrated circuits using regular arrays and gratings

A mask set for a process for providing patterns on a substrate comprising:

• a fine feature mask containing a pattern of dense features;
• a trim mask for producing multiple trimmed patterns of fine features;
• and
• an additional mask or set of masks to provide additional features on a same lithography level as said dense features wherein the imaging of the additional features being substantially independent of the previous exposures and the imaging of the additional features provide a geometric union operation.

A computer-aided design methodology, comprising:

• (a) assuming a first template of dense-only features as a first mask level;
• (b) placing a first set of trim features on a second mask level to coincide with selected features on the first template, such that a first subset or superset of features desired for fabrication correspond to a geometric function of the first template and the first set of trim features;
• and
• (c) placing additional features on additional mask levels, such that features desired for fabrication correspond to a geometric function of the first subset or superset of features desired for fabrication and the additional features, the geometric function being determined by a destination lithographic process in which the imaging of the first subset or superset of features desired for fabrication and the imaging of the additional features are substantially independent.

A design methodology, comprising:

• (a) assuming a first template of dense-only features as a first mask level;
• (b) placing a first set of trim features on a second mask level to coincide with selected features on the first template, such that a first subset or superset of features desired for fabrication correspond to a geometric function of the first template and the first set of trim features;
• and
• (c) placing additional features on additional mask levels, such that features desired for fabrication correspond to a geometric function of the first subset or superset of features desired for fabrication and the additional features, the geometric function being determined by a destination lithographic process in which the imaging of the first subset or superset of features desired for fabrication and the imaging of the additional features are substantially independent.

A method of forming a random contact array on a substrate comprising:

• (a) exposing the substrate to provide a pattern of dense contact features of a predetermined pitch and critical dimension;
• (b) exposing the substrate to provide multiple trimmed patterns on the substrate, the trimmed patterns including both densely populated and sparsely populated regions of features, the critical dimension of the features in the densely populated regions and sparsely populated regions being substantially independent of feature density;
• and
• (c) exposing the substrate to image additional features on a same lithography level as the dense features, the imaging of the additional features being substantially independent of previous exposures, the imaging of the additional features providing a geometric union operation.

A method for defining multiple fine feature critical dimensions in a resist comprising:

• (a) exposing a substrate with a feature definition exposure;
• (b) sub-threshold exposing the substrate using a gray-tone mask to locally partially expose different regions of the substrate, thereby allowing for a range of critical dimensions to be defined by the feature definition exposure, the gray-tone mask being a mask with sub-resolution features of varying pitch that produce a similar dose variation effect;
• and
• (c) degrading a stepper resolution during said sub-threshold exposing by a detuning method.

A method for defining multiple fine feature critical dimensions in a resist, comprising:

• (a) exposing a substrate with a feature definition exposure;
• (b) sub-threshold exposing the substrate using a gray-tone mask to locally partially expose different regions of the substrate, thereby allowing for a range of critical dimensions to be defined by the feature definition exposure, the gray-tone mask being a mask with sub-resolution features of varying pitch that produce a similar dose variation effect;
• and
• (c) degrading a stepper resolution during said sub-threshold exposing by decreasing a partial coherence of an exposure.

A method for defining multiple fine feature critical dimensions in a resist, comprising:

• (a) exposing a substrate with a feature definition exposure;
• (b) sub-threshold exposing the substrate using a gray-tone mask to locally partially expose different regions of the substrate, thereby allowing for a range of critical dimensions to be defined by the feature definition exposure, the gray-tone mask being a mask with sub-resolution features of varying pitch that produce a similar dose variation effect;
• and
• (c) degrading a stepper resolution during said sub-threshold exposing by decreasing a numerical aperture of a lens.