Specific Process Knowledge/Lithography/Aligners/Aligner: Maskless 01 processing: Difference between revisions
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The alignment accuracy of the Aligner: Maskless 01 is a combination of the position accuracy of the stage, the accuracy of the alignment mark detection, and the accuracy of the pattern already on the wafer (first print). | The alignment accuracy of the Aligner: Maskless 01 is a combination of the position accuracy of the stage, the accuracy of the alignment mark detection, and the accuracy of the pattern already on the wafer (first print). | ||
<br/> By measuring the stitching accuracy between two layers printed on the same substrate (without unloading the substrate), we can assess the stage accuracy. By aligning to a pattern previously exposed by the Aligner: Maskless 01, we can assess the mark detection accuracy. And finally, by aligning to a pattern exposed on a mask aligner, we can assess the mask-less aligner's ability to compensate for any scaling and orthogonality errors between the two machines. | <br/> By measuring the stitching accuracy between two layers printed on the same substrate (without unloading the substrate), we can assess the stage accuracy. By aligning to a pattern previously exposed by the Aligner: Maskless 01, we can assess the mark detection accuracy. And finally, by aligning to a pattern exposed on a mask aligner, we can assess the mask-less aligner's ability to compensate for any scaling and orthogonality errors between the two machines. | ||
The results reported here use printed verniers to assess the misalignment along the two axes at different points on the wafer using an optical microscope. Two different designs were used; a ±5µm vernier and a ±1µm vernier. Both consist of a scale of 10µm lines with 10µm pitch, and a vernier scale to enable subdivision of the 5µm or 1µm scale into tenths, i.e. subdivisions of 0.5µm or 0.1µm. During read-out, symmetry enables the observer to read with ±0.25µm or ±0.1µm accuracy. | |||
==Stitching== | ==Stitching== | ||