Systems and methods for stabilizing droplet-plasma interactions through laser energy modulation

摘要

In a laser-generated plasma (LPP) extreme ultra-violet (EUV) system, the droplet is irradiated by a laser pulse to produce a plasma in the chamber. This forces the plasma to be released from the steady state and force the subsequent droplets to change their trajectory and velocity as they approach the plasma. This unstabilization can be detected from oscillations present in the amount of EUV energy produced. A proportional-integral (PI) controller algorithm is used to change the energy of the subsequent laser pulse based on the EUV energy generated in the chamber, in order to stabilize the movement of the plasma and droplet to reduce oscillation. Altering the energy of the subsequent laser pulse stabilizes the plasma, which reduces the effect on droplet advancement and stabilizes the amount of EUV energy produced, so that the plasma chamber can operate for a longer time and is maintained The amount of the preliminary power to be supplied is reduced.