Laser apparatus, pulse width stretching apparatus, and electronic device manufacturing method

An electronic device manufacturing method comprising:

• generating a laser beam having a pulse width stretched by a laser apparatus, the laser apparatus including
• a laser oscillator configured to emit a pulse laser beam,
• a first optical pulse stretcher disposed on an optical path of the pulse laser beam,
• a second optical pulse stretcher disposed on the optical path of the pulse laser beam,
• a third optical pulse stretcher disposed on the optical path of the pulse laser beam;
• and
• a fourth optical pulse stretcher disposed on the optical path of the pulse laser beam,
• when L1 represents an optical path length of a delay optical path of the first optical pulse stretcher, L2 represents an optical path length of a delay optical path of the second optical pulse stretcher, L3 represents an optical path length of a delay optical path of the third optical pulse stretcher, n represents an integer equal to or larger than two, L4 represents an optical path length of a delay optical path of the fourth optical pulse stretcher, and m represents an integer equal to or larger than two,
• L2 being an integral multiple of L1 by an integer equal to or larger than two,
• the integer equal to or larger than two including an allowable range of ±0.25,
• L3 satisfying a condition expressed by
• (n−0.75)×L1≤L3≤(n−0.25)×L1,
• L4 satisfying a condition expressed by
• (m−0.25)×L1≤L4≤(m+0.25)×L1,
• m=n;
• outputting the laser beam to an exposure apparatus or a laser beam irradiation apparatus;
• and
• exposing a photosensitive substrate to the laser beam in the exposure apparatus or irradiating an irradiation target object with the laser beam in the laser beam irradiation apparatus to manufacture an electronic device.