Specific Process Knowledge/Lithography/Aligners/Aligner: Maskless 02 processing: Difference between revisions
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This test was performed by printing two layers on top of each other without unloading the substrate. There is | This test was performed by printing two layers on top of each other without unloading the substrate. There is no alignment performed, so it is a test of the stages ability to address the same spot twice. The first layer was a full 4" wafer, and was printed in ~½ hour. The second layer only consisted of alignment structures in a 5x5 grid, and printed in a few minutes. | ||
The result shows significant misalignment between the two layers, higher than what is seen in true overlay tests. This is believed to be an effect of drift during the first, long print (most likely heating of the stage), as the misalignment is seen to be biggest between parts printed furthest apart in time (i.e. on the left side of the wafer). In a normal overlay print, this error can be at least partially compensated using the scaling and shearing function available for three or more alignment marks/positions. | The result shows significant misalignment between the two layers, higher than what is seen in true overlay tests. This is believed to be an effect of drift during the first, long print (most likely heating of the stage), as the misalignment is seen to be biggest between parts printed furthest apart in time (i.e. on the left side of the wafer). In a normal overlay print, this error can be at least partially compensated using the scaling and shearing function available for three or more alignment marks/positions. | ||