| 摘要 |
PURPOSE:To reduce the time of exposure without losing precision of a projected pattern by a method wherein peripheral parts of an exposed pattern is exposed employing the electron beam of the smaller cross section than that for inner parts of the exposed pattern. CONSTITUTION:Image by an electron beam is projected in alphabetical order a to o. However pattern image of parts e, f, g, j and k are projected utilizing nearly full cross section that is approximately square of 30mum and image of other parts which lie at the periphery are projected utilizing the smaller cross section of 2mumX30mum. By this projection gradation emerging at the pattern image by maximum cross section is corrected by the pattern image by smaller cross section and total precision is apt to rely on the image by smaller cross section. Therefore the exposing time can be reduced and aggregated high accuracy is maintained in spite of high speed of imaging, eliminating gradation due to the scattering of electron by space charge effect which will emerge in the conventional method. |
