Photomask and method of structuring a photoresist by double exposure with imaging auxiliary structures and different exposure tools
AssigneeInfineon Technologies AG
InventorsChristoph Nolscher, Armin Semmler, Gunther Czech
Life of this patent
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Abstract
A method for structuring photoresists and a corresponding photolithography mask utilize a principal structure and an auxiliary structure. In addition to the principal structure to be imaged, the photomask has an imaging auxiliary structure, which improves the imaging of the principal structure. The portions of the imaging auxiliary structure in the photoresist are exposed in a second exposure step and thereby likewise changed into a form that is soluble in a developer. Only the principal structure remains on the substrate after development.
Claims18
A method of structuring a photoresist, which comprises:
- providing a photoresist on a substrate;
- performing a first exposure by exposing the photoresist with a first photomask imaging a principal structure and an imaging auxiliary structure, for improved imaging of the principal structure, onto the photoresist to thereby cause a chemical differentiation of the photoresist between exposed and unexposed regions;
- and
- subsequently performing a second exposure with a second photomask imaging the imaging auxiliary structure on the photoresist but not imaging the principal structure on the photoresist to thereby cause a chemical modification of the photoresist only in imaged portions of the imaging auxiliary structure;
- and
- developing the photoresist with a developer such that only the principal structure is retained on the substrate.
A method of structuring a photoresist, which comprises:
- providing a photoresist on a substrate;
- performing a first exposure by exposing the photoresist with a first photomask imaging a principal structure and an imaging auxiliary structure, for improved imaging of the principal structure, onto the photoresist to thereby cause a chemical differentiation of the photoresist between exposed and unexposed regions;
- and
- subsequently performing a second exposure by exposing the photoresist with a second photomask imaging the imaging auxiliary structure on the photoresist but not substantially imaging the principal structure on the photoresist, to thereby cause a chemical modification of the photoresist only in imaged portions of the imaging auxiliary structure;
- and
- developing the photoresist to develop only the principal structure on the substrate.
A photomask, comprising:
- a principal structure;
- and
- an imaging auxiliary structure spaced apart from said principal structure.
Dependencies are inferred from the claim text.