Specific Process Knowledge/Lithography/EBeamLithography/JEOLPatternPreparation: Difference between revisions

Content and illustration by Thomas Pedersen @ DTU Nanolab unless otherwise noted.

Illustration of SEM mode and alignment and beam scan alignment.

Patterns that contain a mix of fine and large dimension structures can advantageously be broken into a low current and a high current exposure. In this way the fine features can be written at low current (and low speed) and the large structures can be written at high current (and high speed). Some patterns, for instance a fine electrode pattern with large bonding pads, can easily and manually be broken into a fine and coarse part and placed in two different layers. For many patterns this can however be very cumbersome but the process can also be automated with Beamer using "bulk and sleeve" setup.  The concept is illustrated below. In this setup, Beamer will extract the periphery (sleeve) of a pattern into one layer and the bulk of structures into another layer. The bulk is oversized slightly (adding a bias) to ensure overlap between the two patterns at exposure. In this way structures can be defined with best possible edge definition while keeping exposure time down. [https://labmanager.dtu.dk/view_binary.php?fileId=5412 A Beamer flow with a default bulk and sleeve setup can be found here.] A 200 nm sleeve with a 50 nm overlap is a good starting point.

The pre-computed PSF can be loaded from either a separate file, from the local archive or from the global archive. In any case the file will probably originate from a Tracer simulation, for more on this visit our [[Specific_Process_Knowledge/Lithography/EBeamLithography/TRACER|Tracer page.]] It can be advantageus to place your PSF in the global (network) archive such that it is available on the Beamer PC in the cleanroom as well as the Beamer PC outside the cleanroom.