Specific Process Knowledge/Lithography/Aligners/Aligner: Maskless 01 processing: Difference between revisions
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==Substrate centering== | ==Substrate centering== | ||
During | During (4") substrate detection, the sample is scanned along the X- and Y-axes, as well as diagonally. From these measurements, the diameter of the substrate is calculated, as well as the stage position matching the center of the substrate. This stage position will be the default origin for the subsequent exposure. | ||
<br/>Unfortunately, the centering does not compensate for major or minor flats. The center position will therefor typically be displaced several mm from the center of the substrate along the Y-axis due to the major flat, and possibly also shifted due to any minor flats. These shifts have successfully been compensated during file conversion, in order to give a centering accuracy of ±200µm. | <br/>Unfortunately, the centering does not compensate for major or minor flats. The center position will therefor typically be displaced several mm from the center of the substrate along the Y-axis due to the major flat, and possibly also shifted due to any minor flats. These shifts have successfully been compensated during file conversion, in order to give a centering accuracy of ±200µm. | ||
==Flat alignment== | ==Flat alignment== | ||
At the end of | At the end of (4") substrate detection, the sample is scanned twice along the flat, in order to determine the substrate rotation. This angle will be presented in the exposure panel along with the option to expose the design rotated in order to compensate for this angle, i.e. aligned to the flat. | ||
<br/>The flat alignment accuracy has been measured to be 0±0.1° (1.7mRad) quite consistently. Out of a total of 13 exposures, only two were misaligned by more than 0.1° | <br/>The flat alignment accuracy has been measured to be 0±0.1° (1.7mRad) quite consistently. Out of a total of 13 exposures, only two were misaligned by more than 0.1° | ||