Specific Process Knowledge/Lithography/EBeamLithography/JEOLPatternPreparation: Difference between revisions

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 === Boundary box control ===
-In continuation of the example above, if two layers/exposures are to be aligned to each other in subsequent process steps it is vital to control the extend of the boundary box, since '''the ARRAY command places patterns with respect to the center of the bounding box'''.
+In continuation of the example above, if two layers are to be positioned correctly relative to each other it is vital to control the extend of the boundary box, since '''the ARRAY command places patterns with respect to the center of the bounding box'''. In the example above the bounding box of L2 is not symmetric around the design coordinate system (0,0) and hence it will be moved to the substrate center during exposure, unless the user defines an offset in the '''ARRAY''' command that places the pattern.
-that the two layers boundary boxes are identical or at least symmetric around (0,0). With reference to the example below, the boundary boxes can be made identical by either
+The bounding box of L2 can be controlled in two ways:
 *Letting L2 inherit the L1 boundary box (option in Beamer)
 *Placing small corner marks on L2 to force the boundary box as needed
-Corner marks can be 1x1 nm boxes placed outside the substrate to avoid having them exposed onto the substrate.
+In the example below corner marks are placed symmetric around design system (0,0) on L2 and hence the bounding box of L2 is now symmetric around design (0,0). Corner marks can be 1x1 nm boxes, hencce they will be too small to actually show up in the developed resist pattern.
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+Illustration of bounding box control by intentionally adding control geometry to force the bounding box to be symmetric around design system (0,0) on L2.
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