Microlithographic structures and method of fabrication
AssigneeMicron Technology, Inc.
InventorsH. Daniel Dulman, William A. Stanton
Life of this patent
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Abstract
A method of formulating and fabricating a mask pattern and resulting mask for forming isolated or closely spaced contact holes in an integrated circuit. The mask has a transparent mask substrate and patterned regions of attenuating phase shift material and opaque, partially transmissive or transparent material arranged to reduce the effect of side lobes and improve depth of focus. The rims, frames and outrigger patterns for the attenuating phase shift material and opaque, partially transmissive or transparent material are determined according to calculations performed on a processor with imaging software for various optical conditions and exposed feature criteria.
Claims29
A microlithographic mask for forming a sub-resolution feature in photoresist with an acceptable process latitude, said mask comprising:
- a layer of transparent material;
- a layer of light-obstructing material;
- and
- a layer of attenuating phase shifting material located between said layer of transparent material and said layer of light-obstructing material;
- and
- wherein said layer of light-obstructing material and said layer of attenuating phase shifting material are patterned to form a transparent hole, a partially transmissive assist feature, and a light-obstructing frame located between said transparent hole and said partially transmissive assist feature.
A microlithographic mask, comprising:
- transparent material;
- and
- patterned opaque material and phase shifting material, said patterned materials defining an opening, an opaque frame surrounding said opening, sub-resolution bars surrounding said frame, and opaque corners located between sub-resolution bars.
A mask for forming an array of sub-resolution features, said mask comprising:
- a layer of transparent material;
- a layer of light-obstructing material;
- and
- a layer of attenuating phase shifting material located between said layer of transparent material and said layer of light-obstructing material;
- and
- wherein said layer of light-obstructing material and said layer of attenuating phase shifting material are patterned to form transparent holes and light-obstructing frames surrounding said transparent holes.
A multi-tone mask for forming sub-resolution features, said mask comprising:
- a first layer of attenuating phase shifting material, said layer defining openings corresponding to said sub-resolution features;
- and
- a second layer of material for preventing incident light from propagating through said first layer, said second layer including frames surrounding said openings, and wherein said second layer defines bar-shaped partially transmissive assist features.
A mask for forming an elliptical feature in photoresist, said mask comprising:
- a layer of transparent material;
- a layer of opaque material;
- and
- a layer of attenuating phase shifting material located between said layer of transparent material and said layer of opaque material;
- and
- wherein said layer of opaque material and said layer of attenuating phase shifting material are patterned to form transparent holes and opaque frames surrounding said transparent holes.
A method of making a multi-tone microlithographic mask, said method comprising:
- providing sets of dimension data representative of mask patterns;
- for each set of dimension data, calculating feature dimension data as a function of optical conditions;
- and
- for a desired optical condition, identifying the sets of dimension data that have feature dimension data within desired limits.
Dependencies are inferred from the claim text.