Beam dose computing method and writing method and record carrier body and writing apparatus for determining an optimal dose of a charged particle beam

A writing method, comprising:

• specifying a matrix of rows and columns of regions as divided from a surface area of a target object to include first, second and third regions of different sizes, the third regions being less in size than the first and second regions;
• determining first corrected doses of a charged particle beam for correcting fogging effects in the first regions;
• determining corrected size values for correcting pattern line width deviations occurring due to loading effects in the second regions;
• using said corrected size values in said second regions to create a map of base doses of the beam in respective ones of said second regions;
• using said corrected size values to prepare a map of proximity effect correction coefficients in respective ones of said second regions;
• using the maps to determine second corrected doses of said beam for correction of proximity effects in said third regions;
• using the first and second corrected doses to determine an actual beam dose at each position on the surface of said object;
• and
• controlling said beam in accordance with said actual beam dose to thereby write a pattern on said object.

A record carrier body storing therein a processing procedure in a computer readable and executable form, said procedure comprising the steps of:

• specifying a matrix of rows and columns of regions as divided from a surface area of a target object to include first, second and third regions of different sizes, the third regions being less in size than the first and second regions;
• determining first corrected doses of a charged particle beam for correcting fogging effects in the first regions;
• determining corrected size values for correcting pattern line width deviations occurring due to loading effects in the second regions;
• using said corrected size values in said second regions to create a map of base doses of the beam in respective ones of said second regions;
• using said corrected size values to prepare a map of proximity effect correction coefficients in respective ones of said second regions;
• using the maps to determine second corrected doses of said beam for correction of proximity effects in said third regions;
• and
• using the first and second corrected doses to determine an actual beam dose at each position on the surface of said object.

A writing apparatus, comprising:

• a table-like structure supporting thereon a target object;
• a radiation source operative to emit a charged particle beam;
• a pattern generator including more than one deflector and one or more apertures for guiding the beam toward the object to thereby permit writing of a pattern on said object;
• a control unit connected to control said pattern generator, said control unit including,
• first calculator means for specifying a matrix of rows and columns of regions as divided from a surface area of a target object to include first, second and third regions of different sizes, the third regions being less in size than the first and second regions, and for determining first corrected doses of a charged particle beam for correcting fogging effects in the first regions,
• second calculator means for determining corrected size values for correcting pattern line width deviations occurring due to loading effects in the second regions, for creating using said corrected size values in said second regions a map of base doses of the beam and a map of proximity effect correction coefficients in respective ones of said second regions, and determining by using these maps second corrected doses of said beam for correction of proximity effects in said third regions, and
• third calculator means for determining by use of the first and second corrected doses an actual beam irradiation time at each location on the object surface, whereby said control unit controls said deflector to deflect said beam in accordance with said beam irradiation time.