Specific Process Knowledge/Lithography/EBeamLithography/JEOLJobPreparation: Difference between revisions
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The shot time can be calculated as ''t = D·p<sup>2</sup>/I'', where ''D'' is the dose in µC/cm<sup>2</sup>, ''p'' is beam pitch and ''I'' is current. As a practical example let us consider an exposure at 2 nA beam current and a desired dose of 250 µC/cm<sup>2</sup>. At 4 nm beam pitch the shot time will come out to 20 ns, while at 2 nm beam pitch it will come out at 5 ns and thus violate the hardware limitation of 10 ns. In order to expose the pattern with 2 nm shot pitch one would have to choose a lower beam current at the expense of increased writing time. | The shot time can be calculated as ''t = D·p<sup>2</sup>/I'', where ''D'' is the dose in µC/cm<sup>2</sup>, ''p'' is beam pitch and ''I'' is current. As a practical example let us consider an exposure at 2 nA beam current and a desired dose of 250 µC/cm<sup>2</sup>. At 4 nm beam pitch the shot time will come out to 20 ns, while at 2 nm beam pitch it will come out at 5 ns and thus violate the hardware limitation of 10 ns. In order to expose the pattern with 2 nm shot pitch one would have to choose a lower beam current at the expense of increased writing time. | ||
The shot time is in fact such an important number that the system will specifically display the minimum shot time for each sequence at the end of job file compilation as illustrated below. In this case the exposure consists of five sequences with a few different doses and beam currents and the shot pitch (scanstep) has been adjusted to make sure all shot times are below 10 ns. Bear in mind the | The shot time is in fact such an important number that the system will specifically display the minimum shot time for each sequence at the end of job file compilation as illustrated below. In this case the exposure consists of five sequences with a few different doses and beam currents and the shot pitch (scanstep) has been adjusted to make sure all shot times are below 10 ns. Bear in mind the shot pitch (scanstep) is in units of 0.25 nm, thus sequence 1 is written at 4 nm shot pitch. | ||
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