Methods and systems for aligning master oscillator power amplifier systems

A method, comprising:

• ramping up, through a first number of sequential stages, a pumping power input into a laser amplifier chain of a master oscillator power amplifier (MOPA) system until the pumping power input reaches an operational pumping power input level;
• ramping up, through a second number of sequential stages, a signal power output of a seed laser until the signal power output reaches an operational seed laser power output level;
• and
• aligning the MOPA system at each of the second number of sequential stages,
• wherein each of the first number of sequential stages coincides, in time, with one of the second number of sequential stages.

A method, comprising:

• ramping up a pumping power input into a laser amplifier chain of a master oscillator power amplifier (MOPA) system until the pumping power input reaches an operational pumping power input level;
• adjusting a signal power output of a seed laser of the MOPA system until the signal power output is at a first level below an operational power output level;
• performing a coarse optical alignment process to the MOPA system while the pumping power input is at the operational pumping power input level, the signal power output is at the first level, and the MOPA system reaches a steady thermal state;
• ramping up, through a number of ascending stages, the signal power output of the seed laser from the first level to an operational power output level;
• performing a fine optical alignment process to the MOPA system at each of the number of ascending stages to obtain an aligned MOA system;
• irradiating, using the aligned MOPA system, a laser beam toward a target to generate extreme ultraviolet (EUV) radiation;
• collecting and focusing, using a collector, the EUV radiation to serve as a radiation source for an EUV lithography system;
• and
• patterning, using the EUV lithography system, a photoresist layer on a substrate.