Electron beam lithography system and method
AssigneeHitachi, Ltd.
InventorsYoshinori Nakayama, Shinji Okazaki
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Abstract
An electron beam lithography system and method which provide an in-plane current density distribution of an electron beam focussed onto a specimen so as to prevent a proximity effect and space charge effect.
Claims17
An electron beam lithography method, comprising the steps of:
- emitting an electron beam in a fixed predetermined dosage;
- repeating drawing a unit pattern with said electron beam on a substrate wherein a plurality of said unit patterns forms a highly integrated device pattern;
- forming said unit pattern by shaping the electron beam with a first aperture having an aperture pattern matching said unit pattern;
- and
- varying a transmittance of the electron beam with at least one second aperture to selectively control an intensity of an exposure dosage of the electron beam on said substrate.
A method of forming a pattern, comprising:
- coating a resist film on a semiconductor substrate;
- forming a highly integrated circuit pattern by exposing said resist film repeatedly with a unit pattern in individual shots using energy beam lithography emitted from a source in a fixed predetermined dosage for each shot;
- and
- controlling the transmitted beam energy with at least one aperture to vary the transmittance for said shots.
An electron beam lithography method, comprising the steps of:
- forming a highly integrated circuit pattern on a resist film coated on a semiconductor substrate from a plurality of unit patterns;
- emitting an electron beam in a fixed dosage emission of predetermined current density and duration an shaping the beam by passing the beam through a first aperture having a cell projection pattern in the shape of the unit pattern;
- repeatedly exposing the coated substrate with said shaped electron beam;
- and
- controlling said exposing by passing said electron beam through one of a plurality of second apertures to vary an in-plane current distribution of said shaped electron beam for each shot in accordance with predetermined parameters.
An electron beam lithography method, comprising the steps of:
- shaping an electron beam emitted from a source in a fixed predetermined dosage and duration by selecting one of a plurality of cell projection patterns each having a like unit pattern that forms part of a highly integrated circuit device pattern and each having a different transmittance affecting an exposure dosage of the electron beam;
- repeatedly exposing a substrate with the electron beam in the shape of the unit pattern, including exposing a first area of the device pattern with the electron beam shaped by a first one of said plurality of cell projection patterns providing low transmittance and exposing a second area of the device pattern with the electron beam shaped by at least a second one of said plurality of cell projection patterns providing high transmittance.
A method of forming a highly integrated circuit pattern having central and peripheral areas on a resist film coated on a semiconductor substrate using electron beam lithography, comprising:
- emitting an electron beam from a source in a fixed dosage and duration and shaping the electron beam with an aperture defining a unit pattern of said circuit pattern;
- repeatedly exposing the resist with a single shot electron beam of fixed dosage shaped by said aperture to form the circuit pattern;
- controlling the transmittance of the electron beam after the emitting to have a high transmittance about said peripheral area of said integrated device pattern and to have a low transmittance about said central area of said integrated device pattern.
A method of forming a highly integrated circuit pattern according to claim 36, wherein in said controlling step said electron beam is selectively passed through one of a plurality of transmittance affecting apertures having different transmittances, respectively.
Dependencies are inferred from the claim text.