Specific Process Knowledge/Back-end processing/Laser Micromachining Tool/fluence

Fluence

The fluence produces by a laser is, by definition, the energy delivered by a laser pulse ($E_{pulse}$) per surface unit ($S$) and it is given in J/cm2.

The function $E_{pulse}$ is defined as :

$E_{pulse}=\frac{\bar{P}}{f}$

Where $\bar{P}$ (average power) and is measured with the laser sensor power measurement and the repetion rate ($f$) is set in the settings.

The fluence is therefore determinate as such :

$Fluence=\frac{E_{pulse}}{S}$

The theoretical spot sizes ($S$) can be found here