Electron beam exposure method
View Patent ↗An electron beam exposure method includes the steps of: preparing an exposure mask having a plurality of opening patterns formed by dividing a drawing object pattern into exposable regions; and drawing the drawing object pattern by performing exposure with an electron beam passing through the opening patterns of the exposure mask. Each end portion serving as a joint in each opening pattern of the exposure mask is provided with a joining portion tapered in a width of the opening pattern. The exposure is performed in such a way that portions drawn through adjacent joining portions overlap each other.
1. An electron beam exposure method comprising the steps of:
preparing an exposure mask including a linear opening pattern, a gap opening pattern configured by two parallel openings with a gap therebetween, and a circular opening pattern having a diameter equal to a width of the linear opening pattern;
drawing a linear portion of a drawing object pattern by repeating exposure with an electron beam passing through the linear opening pattern;
drawing a curved portion of the drawing object pattern by repeating exposure with an electron beam passing through the circular opening pattern while shifting and overlapping exposure positions of the electron beam; and
drawing a gap portion of the drawing object pattern by one exposure operation with an electron beam passing through the gap opening pattern,
wherein in drawing a junction between the curved portion and the linear portion of the drawing object pattern, the curved portion is drawn in such a manner that a position of a rectangular electron beam to be delivered to the circular opening pattern is adjusted depending on the exposure positions to prevent the electron beam from entering the liner portion from the curved portion.
2. The electron beam exposure method according to claim 1 , wherein
each end portion serving as a joint in the linear opening pattern is provided with a joining portion tapered in a width of the opening pattern, and
in the step of drawing a linear portion of the drawing object pattern, the exposure is performed in such a way that portions drawn through every adjacent joining portions overlap each other.
3. The electron beam exposure method according to claim 1 , wherein the step of drawing a curved portion of the drawing object pattern includes the steps of:
preparing a beam shaping mask for shaping the electron beam to a desired shape before the electron beam reaching the exposure mask; and
adjusting an overlap between the circular opening pattern on the exposure mask and a rectangular beam shot of the electron beam shaped by the beam shaping mask, thereby drawing the curved portion only by a part of the rectangular beam shot overlaps the circular opening pattern.
4. The electron beam exposure method according to claim 3 , wherein the exposure mask further includes guard regions that surround the circular opening pattern.