1. Field of the Invention
The present invention relates to an electron beam lithography apparatus using a patterned emitter. More particularly, the present invention is directed to an electron beam lithography apparatus using a pyroelectric plate on which a patterned metal thin layer is formed as an electron beam source.
2. Description of the Related Art
Conventional apparatus for performing ferroelectric switching lithography using a patterned emitter emit electrons by switching a patterned ferroelectric emitter to expose an electron resist on a substrate to form a desired pattern which is the same as that of the emitter. The conventional ferroelectric switching emission, however, has a drawback in that an electrode formed on the emitter by a mask absorbs electrons. Moreover, the emitter cannot reliably emit electrons when it is not connected to the electrode.
A lithography apparatus, which has a thermal electron source, controls an electron beam using an electro-magnetic field. In order to deploy a large-sized electron source, however, the lithography apparatus is required to include a device for collimating radially diffused electron beams. This requirement introduces complications in the design and structure of the lithography apparatus.
A photocathode projection type lithography apparatus deploys a large-sized electron source but is extremely sensitive to air pollution and therefore cannot be commercially used.
The present invention provides an electron beam lithography apparatus capable of emitting electrons using an electron beam source without applying a high voltage.
The present invention also provides a method of fabricating an electron lithography apparatus that heats an electron beam source at a low temperature to emit electrons, and a method of making the electron beam source.
According to an embodiment of the present invention, there is provided an electron beam lithography apparatus for providing a one-to-one projection of a pattern, comprising a pyroelectric emitter which is disposed from a substrate holder at a predetermined distance, the emitter including a pyroelectric plate having a patterned dielectric layer on its surface facing the substrate holder, wherein portions of the surface of the pyroelectric plate exposed by the patterned dielectric layer is covered with a metal thin layer, a heating source which heats the emitter, and a permanent magnet or an electro-magnet disposed outside the emitter and the substrate holder so as to control the paths of electrons emitted by the emitter.
Preferably, the metal thin layer is formed on the pyroelectric plate that is exposed by the patterned dielectric layer. An adhesion layer of a predetermined thickness may be formed between the pyroelectric plate, and the dielectric layer and the metal thin layer. The dielectric layer and the pyroelectric plate may be sequentially formed below the metal thin layer.
According to another embodiment of the present invention, there is provided an electron lithography apparatus for providing a x-to-one projection of a pattern, comprising a pyroelectric emitter which is disposed from a substrate holder at a predetermined distance, the emitter including a pyroelectric plate having a patterned dielectric layer on its surface facing the substrate holder, wherein portions of the surface of the pyroelectric plate exposed by the patterned dielectric layer is covered with a metal thin layer, a heating source which heats the emitter, and a deflector unit which is disposed between the emitter and the substrate holder so as to control the paths of electrons emitted by the emitter.
According to yet another embodiment of the present invention, there is provided an electron beam lithography apparatus for providing a one-to-one projection of a pattern, comprising a pyroelectric emitter which is disposed from a substrate holder at a predetermined distance, the emitter including a pyroelectric plate having a patterned metal thin layer on its surface facing the substrate holder, wherein a dielectric layer is formed on the pyroelectric plate below the patterned metal thin layer, a heating source which heats the emitter, and a permanent magnet or an electro-magnet disposed outside the emitter and the substrate holder so as to control the paths of electrons emitted from the emitter.
According to still another embodiment of the present invention, there is provided an electron beam lithography apparatus for providing a x-to-one projection of a pattern, comprising a pyroelectric emitter which is disposed from a substrate holder at a predetermined distance, the emitter including a pyroelectric plate having a patterned metal thin layer on its surface facing the substrate holder, wherein a dielectric layer is formed on the pyroelectric plate below the patterned metal thin layer, a heating source which heats the emitter, and a deflector unit which is disposed between the emitter and the substrate holder so as to change the paths of electrons emitted from the emitter.
According to a feature of the present invention, the heating source may be a contact-type heating plate using a resistive-type heating or a remotely controlled heater that generates infrared rays.
According to another feature of the present invention, the pyroelectric plate may be formed of a pyroelectric material selected from the group consisting of LiNbO3, LiTaO3, and BaTiO3.
According to yet another feature of the present invention, the dielectric layer or the adhesion layer may be formed of a dielectric material selected from the group consisting of SiO2, Si3N4, and TiO2.
According to still another feature of the present invention, the metal thin layer may be formed of metal selected from the group consisting of Ti, Au, Pt, Ta, and Al.
According to another feature of the present invention, the deflector unit may include deflection plates which deflect electrons emitted from the emitter, at least one magnetic lens which collimates the deflected electrons, and an aperture which filters the collimated electrons.
According to yet another feature of the present invention, the heating source may heat the emitter to a temperature up to 120xc2x0 C.