Specific Process Knowledge/Lithography/Resist/UVresist: Difference between revisions
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In the maskless aligners, the dose is set directly as a process parameter in the job. In mask aligners, on the other hand, the parameter that is set is the exposure time, i.e. how long the shutter is open during the exposure. | In the maskless aligners, the dose is set directly as a process parameter in the job. In mask aligners, on the other hand, the parameter that is set is the exposure time, i.e. how long the shutter is open during the exposure. | ||
The exposure dose, ''D'' [J/m<sup>2</sup>], is given by: | The exposure dose, ''D'' [J/m<sup>2</sup>], in terms if exposure light intensity ''I'' [W/m<sup>2</sup>] and exposure time ''t'' [s], is given by: | ||
<math>D=I \sdot t</math> | |||
Since the intensity is specific to the spectral sensitivity of the sensor used to measure the exposure light, and the exposure time is specific to the spectral distribution of the exposure light (cf. spectral sensitivity), this dose is specific to the combination of exposure source and optical sensor. | |||
Given an exposure dose, the exposure time, ''t'', is calculated as: | Given an exposure dose, the exposure time, ''t'', is calculated as: | ||
<math>t = D \sdot I^{-1}</math> | |||
It is important to keep in mind that this exposure time is valid only for a specific combination of exposure source and optical sensor, as well as for a specific development process. | It is important to keep in mind that this exposure time is valid ''only'' for a specific combination of exposure source and optical sensor, as well as for a specific development process. | ||
==Exposure dose for mask aligners== | ==Exposure dose for mask aligners== | ||