Specific Process Knowledge/Lithography/EBeamLithography: Difference between revisions
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* Global marks: You need at least two wafer marks, a P mark and a Q mark. It is recommended to have many P and Q marks available on the wafer to choose from. The x-coordinate of the P mark should be smaller than the x-coordinate of the Q mark. The global marks should either be crosses or L-shaped, they should be as narrow as possible and 500 - 1000 microns in length. If the wafer contains a number of identical marks, the marks should be marked in order to identify the 'right' alignment mark (the scan width of the SEM is 1 mm x 1 mm). Text around the wafer mark is NOT recommended. Wafer marks formed as crosses with lengths of 1000 microns and 3-5 microns in width are recommended. | * Global marks: You need at least two wafer marks, a P mark and a Q mark. It is recommended to have many P and Q marks available on the wafer to choose from. The x-coordinate of the P mark should be smaller than the x-coordinate of the Q mark. The global marks should either be crosses or L-shaped, they should be as narrow as possible and 500 - 1000 microns in length. If the wafer contains a number of identical marks, the marks should be marked in order to identify the 'right' alignment mark (the scan width of the SEM is 1 mm x 1 mm). Text around the wafer mark is NOT recommended. Wafer marks formed as crosses with lengths of 1000 microns and 3-5 microns in width are recommended. | ||
* Chip marks: Prepare 1 or 4 chip marks on every chip. The chip marks can be smaller than global marks, as only very fine alignment is performed with chip marks. The chip marks should either be crosses or L-shaped and text around the marks is NOT recommended. | * Chip marks: Prepare 1 or 4 chip marks on every chip. The chip marks can be smaller than global marks, as only very fine alignment is performed with chip marks. The chip marks should either be crosses or L-shaped and text around the marks is NOT recommended. | ||
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== Field stitching == | == Field stitching == | ||
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[[File:FieldToField.png|700px]] | [[File:FieldToField.png|700px]] | ||
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== Overlay accuracy (layer to layer stitching) == | == Overlay accuracy (layer to layer stitching) == | ||