| 摘要 |
PURPOSE:To prevent the occurrence of the difference of pattern line width when drawing a required pattern by irradiating an electron beam to a negative resist surface, by making the irradiation width of the electron beam thicker as time passes from the start of drawing. CONSTITUTION:According to a relation derived from leaving time in vacuum - pattern dimension variation characteristic and exciting current of electron lens - focal length characteristic as shown in the figure, the exciting current is increased so that an irradiating electron beam diameter may be increased with irradiation time to correct pattern dimension variation. Generally in a negative resist, crosslinking reaction proceeds from radical ions caused by electron rays received and this part becomes a drawing pattern, but as the radical ions do not go out after the end of electron beam irradiation and promote the crosslinking reaction, the pattern dimension increases as time passes. By doing as above, such variation of the pattern dimension is corrected and the occurrence of the difference of a pattern line width can be prevented. |
