| 摘要 |
<p>The present invention relates to methods and procedures for determining resist temperature during energy beam lithography and adjusting process parameters, including reducing the beam current, to compensate for increased resist sensitivity due to heating. The present invention relates to methods of predicting resist heating in real-time as the writing proceeds thereby enabling beam compensation to be performed in real-time. A linear superposition approximation is described that provides a procedure for estimating the resist temperature at the point presently being written from previously written points. The present invention makes use of the thermal history of the pattern previously written as that history is recorded in the line of pixels immediately preceding the line whose temperature is to be determined prior to e-beam exposure, and a single number representing the thermal history of lines written before the immediately preceding line. The iterative methods for calculating resist heating in the present invention may be implemented digitally on a variety of devices. In addition, specific analogue circuitry to reproduce this iterative method is described, leading to rapid calculations of resist heating. Advantages of the present invention include the prevention or mitigation of pattern blooming as incident electrons heat the resist and broaden the region of exposure.</p> |
