Electron beam exposure method and system for exposing a pattern on a substrate with an improved accuracy and throughput

A method for exposing a pattern on an object by means of an electron beam, comprising the steps of:

• shaping a single electron beam to form a plurality of electron beam elements respectively of a common size and shape and extending generally in parallel with respect to each other and forming an electron beam pattern;
• radiating said plurality of electron beam elements on said object thereby to expose said pattern on said object as an assembly of corresponding exposure dots arranged with a predetermined pitch;
• said step of shaping the electron beam being conducted so as to produce said plurality of electron beam elements, simultaneously, as a plurality of electron beam element groups, each group including plural and respectively associated said electron beam elements extending in parallel with respect to each other and aligned in a first direction, and such that said electron beam elements aligned in said first direction are repeated in a second direction perpendicular to said first direction, said step of shaping the electron beam being further conducted So as to produce said electron beams of said plurality of electron beam groups simultaneously;
• and
• forming each of said electron beam elements included in one of said electron beam groups, with respect to corresponding electron beam elements in the other electron beam groups, with an offset of said predetermined pitch multiplied by M/N in at least one of said first and second directions, wherein N stands for the number of the electron beam groups and M represents an arbitrary integer smaller than N.

An electron beam exposure system for exposing a pattern on an object by a focused electron beam, comprising:

• electron beam source means for producing an electron beam and emitting the beam along an optical axis;
• focusing means, provided on said optical axis, for focusing said electron beam on said object;
• electron beam shaping means for shaping said electron beam and thereby forming a plurality of electron beam elements of a common size and shape;
• shaping control means for controlling said electron beam shaping means such that said plurality of electron beam elements are formed according to a desired exposure pattern;
• deflection means for deflecting said plurality of shaped electron beam elements with respect to said optical axis;
• said electron beam shaping means comprising a mask plate provided with a plurality of apertures for shaping said single electron beam and thereby to form said plurality of electron beam elements in correspondence to said plurality of apertures and a deflection device, provided on each of said plurality of apertures, which selectively deflects each said electron beam element upon passage through a corresponding said aperture;
• said shaping control means producing, and supplying, a drive signal to said deflection device and forming said plurality of electron beam elements according to said desired exposure pattern;
• said plurality of apertures on said mask being arranged in a first direction and in a second, different direction with a predetermined pitch and thereby to form a plurality of aperture groups each extending in said first direction and repeated, in said second direction, N times and with said predetermined pitch;
• said shaping control means supplying drive signals to said deflection devices in said plurality of aperture groups such that the drive signal supplied to one of the aperture groups is independent of the drive signals supplied to the other aperture groups;
• and
• in each of said aperture groups, said apertures being repeated in said first direction with said predetermined pitch and such that each of said apertures is offset from a corresponding aperture in an adjacent aperture group by M/N pitches in at least one of said first and second directions wherein N stands for the number of aperture groups and M represents an arbitrary Integer smaller than N.

A method for exposing a pattern on an object by means of an electron beam, comprising the steps

• shaping a single electron beam so as to form a plurality of electron beam elements having a common size and shape and such that said plurality of electron beam elements forms an electron beam pattern;
• radiating said plurality of electron beam elements on said object thereby to expose said pattern on said object as an assembly of exposure dots arranged with a predetermined pitch;
• and
• said step of shaping the electron beam further comprising
• passing said electron beam through a mask which has a plurality of apertures that are selectively turned on and turned off in response to said pattern to be exposed on said object;
• adjusting the timing of energization of said apertures such that said respective energizations of said apertures are achieved coincident with a predetermined timing.

A method for exposing a pattern on an object, comprising the steps

• producing an electron beam such that said electron beam travels toward said object along an optical axis;
• shaping said electron beam according to exposure data and so as to form a plurality of electron beam elements aligned in a first direction and having a common, identical size and shape and such that said plurality of electron beam elements forms an exposure pattern corresponding to said exposure data;
• scanning said electron beam elements in a second direction, perpendicular to said first direction, thereby to expose said object;
• said step of shaping further comprising the steps of:
• (a) shaping said electron beam according to first exposure data to form first electron beam elements;
• and
• (b) shaping said electron beam according to second exposure data to form second electron beam elements;
• said step of scanning being conducted such that said first electron beam elements scan over a first area of said object said second electron beam elements scan over a second area of said object, and said first area overlaps with said second area;
• and
• said steps (a) and (b) being conducted such that each of said first electron beam elements has a beam density, indicative of the number of the electron beam elements radiated upon a unit area, which is substantially smaller than the beam density of said second beam elements.