Claims
- 1. A method for making a mask for optically transferring a lithographic pattern corresponding to an integrated circuit from said mask onto a semiconductor substrate by use of an optical exposure tool, said method comprising the steps of:
- forming a plurality of features on said mask, said features corresponding to elements forming said integrated circuit, and
- forming a plurality of non-resolvable biasing segments disposed on an edge of at least one of said features, said plurality of non-resolvable biasing segments disposed on an edge of at least one of said features being substantially equally spaced from one another by a distance--s, each of said plurality of said non-resolvable biasing segments having a predetermined width--w, and a predetermined length--d, said plurality of said non-resolvable biasing segments defining a critical halftone period which equals d+s,
- wherein said mask is utilized in a photolithography process comprising an exposure source having a wavelength--.lambda. and an imaging objective lens having a numerical aperture--NAo, and said critical halftone period of said non-resolvable biasing segments is less than 0.61 multiplied by (.lambda./NAo).
- 2. The method of making a mask according to claim 1, wherein said plurality of features exhibit a feature pitch which is less than 3.lambda..
- 3. The method of making a mask according to claim 1, wherein a plurality of said non-resolvable biasing segments are formed on at least two edges of at least one of said plurality of features.
- 4. The method of making a mask according to claim 1, wherein a plurality of said non-resolvable biasing segments are formed on at least two edges of a plurality of said features.
- 5. A photolithography mask for optically transferring a lithographic pattern corresponding to an integrated circuit from said mask onto a semiconductor substrate by use of an optical exposure tool, said mask comprising:
- a plurality of features corresponding to elements forming said integrated circuit, and
- a plurality of non-resolvable biasing segments disposed on an edge of at least one of said features, said plurality of non-resolvable biasing segments disposed on an edge of at least one of said features being substantially equally spaced from one another by a distance--s, each of said plurality of said non-resolvable biasing segments having a predetermined width--w, and a predetermined length--d, said plurality of said non-resolvable biasing segments defining a critical halftone period which equals d+s,
- wherein said mask is utilized in a photolithography process comprising an exposure source having a wavelength--.lambda. and an imaging objective lens having a numerical aperture--NAo, and said critical halftone period of said non-resolvable biasing segments is less than 0.61 multiplied by (.lambda./NAo).
- 6. The photolithography mask according to claim 5, wherein said plurality of features exhibit a feature pitch which is less than 3.lambda..
- 7. The photolithography mask according to claim 5, wherein a plurality of said non-resolvable biasing segments are formed on at least two edges of at least one of said plurality of features.
- 8. The photolithography mask according to claim 5, wherein a plurality of said non-resolvable biasing segments are formed on at least two edges of a plurality of said features.
- 9. The photolithography mask according to claim 5, wherein the amount of bias exhibited by a given edge of a feature is variable by adjusting the ratio between d and s exhibited by the plurality of non-resolvable bias segments disposed on said given edge.
Parent Case Info
This Application claims domestic priority to Provisional Application No. 60/066,396 filed Nov. 24, 1997.
US Referenced Citations (13)