Method of drawing a pattern on a base material by scanning a beam

A method of drawing a pattern on a base material by scanning an electron beam emitted from an electron beam generator, said method comprising:

• determining field coordinates to divide the base optical surface into at least a first pattern-drawn field and a second pattern-drawn field adjacent to the first pattern-drawn field based on:
• configuration data of the base optical surface of the base material, pattern data of the pattern to be drawn, and a scanning width of the electron beam;
• storing first field coordinate data of the first pattern-drawn field and second field coordinate data of the second pattern-drawn field in a storing section;
• retrieving the first field coordinate data of the first pattern-drawn field from the storing section;
• shifting at least one of the electron beam generator and the base material with respect to each other based on the retrieved first field coordinate data so as to position the electron beam generator and the base material for scanning the electron beam on the first pattern-drawn field;
• determining a first dose distribution for the first pattern-drawn field based on the first field coordinate data and the pattern data;
• drawing a first part of the pattern on a first pattern-drawn field on the base material by scanning the electron beam on the first pattern-drawn field based on the first dose distribution;
• retrieving the second field coordinate data of the second pattern-drawn field from the storing section;
• shifting at least one of the electron beam generator and the base material based on the retrieved second field coordinate data so as to position the electron beam generator and the base material for scanning the electron beam on the second pattern-drawn field;
• determining a second dose distribution for the second pattern-drawn field based on the second field coordinate data and the pattern data;
• and
• drawing a second part of the pattern on the second pattern-drawn field by scanning the electron beam on the second pattern-drawn field based on the second dose distribution;
• wherein the first part of the pattern and the second part of the pattern each include a plurality of ring-shaped zones each of which is formed by a slope portion and a side wall portion;
• wherein the field coordinates are determined such that a boundary between the first pattern-drawn field and the second pattern-drawn field is positioned at a joint portion connecting one of said slope portions and one of said side wall portions;
• and
• wherein the electron beam generator and the base material are shifted with respect to each other such that a boundary between the first pattern-drawn field and the second pattern-drawn field is positioned at a joint portion connecting one of said slope portions and one of said side wall portions.