A lithography system includes an electron source, a lens, and a stencil mask. The electron source emits a beam of electrons. The lens converts the emitted beam of electrons into a diffuse beam of parallel electrons. The stencil mask is positioned between the lens and a semiconductor wafer with an electron-sensitive resists. The stencil mask has a pattern to selectively pass portions of the diffuse beam of parallel electrons onto the electron-sensitive resist of the wafer.

In one embodiment, a charged particle beam writing apparatus includes a writer writing a pattern on a substrate on a stage with a charged particle beam, a mark substrate disposed on the stage and having a mark, an irradiation position detector detecting an irradiation position of the charged particle beam on a mark surface, a height detector detecting a surface height of the substrate and the mark substrate, a drift correction unit calculating an amount of drift correction, and a writing control unit correcting the irradiation position of the charged particle beam by using the amount of drift correction. The mark substrate has a pattern region with a plurality of marks and a non-pattern region with no pattern therein, and at least part of the non-pattern region is disposed between different portions of the pattern region. The height detector detects a height of a detection point in the non-pattern region.

In one embodiment, a charged particle beam writing apparatus includes a writer writing a pattern on a substrate placed on a stage by irradiating the substrate with a charged particle beam, a height detector detecting a surface height of a mark on the stage, an irradiation position detector detecting an irradiation position of the charged particle beam on the mark surface by irradiation with the charged particle beam focused at the surface height of the mark, a drift correction unit calculating an amount of drift of the charged particle beam on the mark surface from the irradiation position detected by the irradiation position detector, and generating correction information for correcting a shift in irradiation position caused by a drift on the substrate surface based on the amount of drift, and a writing control unit correcting the irradiation position of the charged particle beam by using the correction information.

A charged-particle beam exposure method includes providing a sample that has patterns having shot densities different from each other, using the sample to obtain pattern drift values correlated with the shot densities, and irradiating the sample with a charged-particle beam to perform an exposure process on the sample. The irradiating of the sample with the charged-particle beam is carried out while a deflection voltage, which is applied to the charged-particle beam to deflect the charged-particle beam, is corrected based on the pattern drift value corresponding to a shot density of a pattern to be formed on the sample.

A charged-particle beam exposure method includes providing a sample that has patterns having shot densities different from each other, using the sample to obtain pattern drift values correlated with the shot densities, and irradiating the sample with a charged-particle beam to perform an exposure process on the sample. The irradiating of the sample with the charged-particle beam is carried out while a deflection voltage, which is applied to the charged-particle beam to deflect the charged-particle beam, is corrected based on the pattern drift value corresponding to a shot density of a pattern to be formed on the sample.

One embodiment relates to an apparatus for aberration correction in an electron beam lithography system. An inner electrode surrounds a pattern generating device, and there is at least one outer electrode around the inner electrode. Each of the inner and outer electrodes has a planar surface in a plane of the pattern generating device. Circuitry is configured to apply an inner voltage level to the inner electrode and at least one outer voltage level to the at least one outer electrode. The voltage levels may be set to correct a curvature of field in the electron beam lithography system. Another embodiment relates to an apparatus for aberration correction used in an electron based system, such as an electron beam inspection, or review, or metrology system. Other embodiments, aspects and features are also disclosed.