Laser apparatus and electronic device manufacturing method

A laser apparatus comprising:

• a master oscillator configured to emit a laser beam;
• an amplifier including an optical resonator and configured to amplify the laser beam emitted by the master oscillator in the optical resonator;
• and
• a phase shift structure disposed on an optical path between the master oscillator and the amplifier at a position closer to the amplifier than a middle point of the optical path,
• the phase shift structure including a plurality of cells having different phase shift amounts for the laser beam,
• the cells having a disposition interval of λ/(1.5·θAmax) to λ/θAmin inclusive when λ represents a wavelength of the laser beam, θAmax represents an upper limit of a beam expansion angle of the laser beam emitted from the amplifier, and θAmin represents a lower limit of the beam expansion angle.

An electronic device manufacturing method comprising:

• generating a laser beam amplified by an amplifier by using a laser apparatus, the laser apparatus including
• a master oscillator configured to emit a laser beam,
• the amplifier including an optical resonator and configured to amplify the laser beam emitted by the master oscillator in the optical resonator, and
• a phase shift structure disposed on an optical path between the master oscillator and the amplifier at a position closer to the amplifier than a middle point of the optical path,
• the phase shift structure including a plurality of cells having different phase shift amounts for the laser beam,
• the cells having a disposition interval of 80 μm to 275 μm inclusive;
• emitting the amplified laser beam to an exposure apparatus;
• and
• exposing a photosensitive substrate to the amplified laser beam in the exposure apparatus to manufacture an electronic device, wherein
• the amplifier includes a pair of discharge electrodes disposed opposite each other across a discharge space through which the laser beam passes, and
• when a Z direction is defined to be a traveling direction of the laser beam emitted from the amplifier, a V direction is defined to be a discharge direction of the discharge electrodes, an H direction is defined to be a direction orthogonal to the V direction and the Z direction, a first direction is defined to be an in-surface direction of the phase shift structure corresponding to the V direction in a beam section of the laser beam emitted from the amplifier, and a second direction is defined to be an in-surface direction of the phase shift structure corresponding to the H direction in the beam section,
• a length of each of the cells in the first direction is different from a length of the cell in the second direction.