Ultraviolet laser apparatus and electronic device manufacturing method

An electronic device manufacturing method comprising:

• generating laser light amplified by an amplifier using an ultraviolet laser apparatus including
• an oscillation-stage laser configured to output linearly polarized pulse laser light having ultraviolet wavelengths,
• the amplifier configured to amplify the pulse laser light and output the amplified pulse laser light, and
• an optical isolator disposed on an optical path between the oscillation-stage laser and the amplifier,
• the optical isolator including
• a first Faraday rotator configured to rotate a polarization direction of the pulse laser light output from the oscillation-stage laser by a first angle in a first rotation direction with aid of a magnetic field in a first direction,
• a first polarizer so disposed that normalized transmittance for the pulse laser light that exits out of the first Faraday rotator is greater than or equal to 0.9,
• a second Faraday rotator configured to rotate the polarization direction of the pulse laser light passing through the first polarizer by a second angle in a second rotation direction that is an opposite direction to the first rotation direction with aid of a magnetic field in a second direction that is an opposite direction to the first direction, and
• a second polarizer so disposed that the normalized transmittance for the pulse laser light that exits out of the second Faraday rotator is greater than or equal to 0.9;
• outputting the amplified laser light to an exposure apparatus;
• and
• exposing a photosensitive substrate to the laser light in the exposure apparatus to manufacture electronic devices.

A system comprising:

• an ultraviolet laser apparatus;
• and
• an exposure apparatus, wherein
• the ultraviolet laser apparatus comprises:
• an oscillation-stage laser configured to output linearly polarized pulse laser light having ultraviolet wavelengths;
• an amplifier configured to amplify the pulse laser light and output the amplified pulse laser light;
• and
• an optical isolator disposed on an optical path between the oscillation-stage laser and the amplifier,
• the optical isolator including
• a first Faraday rotator configured to rotate a polarization direction of the pulse laser light output from the oscillation-stage laser by a first angle in a first rotation direction with aid of a magnetic field in a first direction,
• a first polarizer so disposed that normalized transmittance for the pulse laser light that exits out of the first Faraday rotator is greater than or equal to 0.9,
• a second Faraday rotator configured to rotate the polarization direction of the pulse laser light passing through the first polarizer by a second angle in a second rotation direction that is an opposite direction to the first rotation direction with aid of a magnetic field in a second direction that is an opposite direction to the first direction, and
• a second polarizer so disposed that the normalized transmittance for the pulse laser light that exits out of the second Faraday rotator is greater than or equal to 0.9, and wherein
• the exposure apparatus is configured to expose a photosensitive substrate to the pulse laser light amplified by the amplifier.