| 摘要 |
This invention provides a method of using an electron beam exposure system having an electron beam with a variable shape to form patterns in a layer of resist on a substrate, a mask substrate or an integrated circuit wafer, while maintaining adequate critical dimension control and beam stability. This is accomplished by setting the electron beam to a fixed square beam with a width set to provide optimum XY critical dimension control for exposing a frame pattern surrounding the original pattern. The frame pattern has a width of a first distance and surrounds the outer perimeter of the original pattern. This provides optimum XY critical dimension control at the outer perimeter of the original pattern. The remainder of the exposure field, which is the exposure field with the original pattern and the frame pattern subtracted away is exposed using an electron beam having a variable size and shape. In one embodiment the exposure of the frame pattern is completed before the exposure of the remainder pattern is carried out. Alternatively, the exposure of the remainder pattern can be completed before the exposure of the frame pattern is carried out. The digital design data for the frame pattern and the remainder of the exposure field is formed using a computer processor and the original design data.
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