| 摘要 |
A more efficient method of macro placement and graying for electron beam (e-beam) lithography. The e-beam field is divided into smaller subfields. Repetitious shapes or collections of shapes which are repetitious are represented by macros. Some shapes span or are intersected by subfield boundaries. After the shapes are converted to fill rectangles and the fill rectangles are proximity corrected, the macro containing the proximity corrected fill rectangles is grayed and placed without being unnested. First, the Macro Organization Step, the macro's fill rectangles are sorted. Tall-narrow macros are sorted top to bottom then left to right, short-wide macros are sorted left to right then top to bottom. After the sort, chains of rectangles are created and a shadow is generated for the macro and for each chain. Next, the Macro Placement and Graying Step, a determination is made of whether and where macro graying will be required. The macro shadow is transformed into subfield coordinates and a determination is made of whether the transformed shadow intersects with (spans) a subfield boundary. If the macro's shadow touches more than one subfield (spans a subfield boundary), then the macro's chain shadows are examined to determine if any chain spans the boundary. Graying is done on any spanning chain. Gray-spliced rectangles and single rectangles are placed in the pattern buffer. Partial macro read commands are placed in the pattern buffer for chains or partial chains resulting from gray-splicing.
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