Patent ID: 6064071
Filing Date: 2000-05-16
Classification: B82Y,H01J

Abstract:
A charged-particle-beam optical system for projecting patterns from a mask onto a sensitized substrate using a charged-particle beam, the optical system comprising, from object-wise to image-wise along an optical axis:a condenser lens situated to receive a charged-particle beam and direct the charged-particle beam to the mask, the condenser lens producing a magnetic field;a first projection lens situated to receive the charged-particle beam from the mask and form a crossover, the first projection lens producing a magnetic field, wherein on-axis axial components of the magnetic fields produced by the first projection lens and the condenser lens are in a first direction;a crossover aperture situated at a crossover of the charged-particle beam;a second projection lens situated to receive the charged-particle beam from the crossover aperture and direct the charged-particle beam to the sensitized substrate, the second projection lens producing a magnetic field;an immersion lens situated so that the sensitized substrate is between the immersion lens and the second projection lens, the immersion lens producing a magnetic field, the on-axis axial components of the magnetic fields produced by the immersion lens and the second projection lens being in a second direction opposite to the first direction; anda plurality of deflectors situated along the optical axis between the mask and sensitized substrate, the deflectors being activatable to deflect the charged-particle beam and establish an effective optical axis, wherein a principal ray from an off-axis point on the mask coincides with the effective optical axis and passes through the center of the crossover aperture.