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Hiroshi Ohsawa

Nobuyoshi Tanaka

Masaki Hirayama

Nobumasa Suzuki

Toshikuni Shinohara

Tadahiro Ohmi

In a laser oscillating apparatus for exciting a laser gas in a laser tube by introducing an electromagnetic wave from a waveguide into the laser tube through a plurality of slots formed in a waveguide wall, and generating a laser beam by resonating light emitted from the laser gas, the slots are formed in a line such that their longitudinal direction is consistent with the longitudinal direction of the waveguide, and a metal wall is so formed as to surround these slots. This metal wall forms a gap as a microwave passage from the slots to a window in the laser tube wall, thereby spacing the laser tube wall apart from the slots by a predetermined distance.

Laser oscillating apparatus, exposure apparatus using the same and device fabrication method

An excimer laser gas in a laser tube is excited by a microwave introduced from awaveguide , and electric field concentration occurs in a slit-shaped gap provided in a plate member , causing plasma discharge. Then the phase of plasma light is regulated and the light is resonated, to cause excimer laser light. This construction realizes plasma excitation entirely uniform along a lengthwise direction of laser light emission, and enables uniform laser light emission with minimum energy loss.

Laser oscillating apparatus, exposure apparatus, and device fabrication method

In a slot array structure, electromagnetic wave emission which is uniform as a whole over the length of a laser tube is realized to allow uniform laser emission with minimum energy loss. Slots ( ) are formed at a predetermined pitch in a long end face (H plane) of each waveguide ( ) along a central line (m) in the longitudinal direction of the H plane to be alternately located on the left and right sides of the central line (m) and spaced apart from the central line (m) by a distance (d).

Laser oscillating apparatus with slotted waveguide

A plasma is excited uniformly as a whole over the length of each slot. A laser oscillating apparatus is designed to excite a laser gas in a laser tube ( ) by introducing electromagnetic waves into the laser tube through a plurality of slots ( ) formed in a waveguide wall and generate a laser beam by resonating the light generated from the laser gas. A least one electrode ( ) is placed near the slot ( ). By giving a predetermined current density to the electrode ( ), the intensity distribution of light generated from the laser gas above the slot ( ) is controlled.

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Utsunomiya, Japan

Hiroshi Ohsawa