Specific Process Knowledge/Lithography/EBeamLithography: Difference between revisions
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'''1''' | '''1 Material:''' The marks should be clearly visible in a 100keV SEM, i.e. preferably defined by Ti/Au or another 'heavy' metal, alternatively the wafer marks should be etched. Shallow etched (even 200 nm etched profiles) global marks or global marks defined by a light metal as Al can be hard to locate manually as well as automatically. | ||
'''2''' | '''2 Design: ''' | ||
* 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: | * Chip marks: | ||