US 6,018,537 A · Reliable, modular, production quality narrow-band high rep rate F.sub.2 laser

Abstract

The present invention provides a reliable modular production quality excimer laser capable of producing 10 mJ laser pulses in the range of 1000 Hz to 2000 Hz or greater. Replaceable modules include a laser chamber; a pulse power system comprised of three modules; an optical resonator comprised of a line narrowing module and an output coupler module; a wavemeter module, an electrical control module, a cooling water module and a gas control module. Important improvements have been provided in the pulse power unit to produce faster rise time and improved pulse energy control. These improvements include an increased capacity high voltage power supply with a voltage bleed-down circuit for precise voltage trimming, an improved commutation module that generates a high voltage pulse from the capacitors charged by the high voltage power supply and amplifies the pulse voltage 23 times with a very fast voltage transformer having a secondary winding consisting of a single four-segment stainless steel rod. A novel design for the compression head saturable inductor greatly reduces the quantity of transformer oil required and virtually eliminates the possibility of oil leakage which in the past has posed a hazard.

Claims37

Dependent claims

A very narrow band reliable modular production quality high repetition rate ArF excimer laser for producing a narrow band pulsed laser beam at repetition rates of at least about 1000 Hz, said laser comprising:

A. a quickly replaceable laser chamber module comprising a laser chamber comprising:
1) two elongated electrodes;
2) a laser gas comprised of
a) fluorine, and
b) a noble gas;
3) a gas circulator for circulating said gas between said electrodes at speeds of at least two cm/millisecond
B. a modular pulse power system comprised of at least one quickly replaceable module, said system being comprised of a power supply and pulse compression and amplification circuits and pulse power controls for producing high voltage electrical pulses of at least 14,000 volts across said electrodes at rates of at least about 1000 Hz;
and
C. a laser pulse energy control system for controlling the voltage provided by said pulse power system, said control system comprising a laser pulse energy monitor and a computer processor programmed with an algorithm for calculating, based on historical pulse energy data, electrical pulses needed to produce laser pulses having pulse energies within a desired range of energies.

6 more elements

A reliable modular production quality high repetition rate excimer laser for producing a narrow band pulsed laser beam at a repetition rate of at least about 1 Khz, said laser comprising:

A. a quickly replaceable laser chamber module comprising:
1) two elongated electrodes
2) a laser gas comprised of fluorine and a buffer gas,
3) a gas circulator system for circulating said laser gas between said electrodes at at least two cm/millisecond comprising:
a) a braze-free blade structure defining a shaft,
b) a brushless motor for rotating said shaft,
c) magnetic bearings for supporting said shaft said motor and said bearings having rotors attached to said shaft and sealed within an environment exposed to said laser gas and said motor and said bearings having a stator outside of said laser gas environment,
B. a pulse power system substantially contained within at least one quickly replaceable module and comprising:
1) a processor controlled high voltage power supply for periodically, at rates of at least about 1000 Hz, charging with electrical energy a charging capacitor to a predetermined pulse control voltage,
2) a compression and amplification circuit for connecting electrical energy stored on said charging capacitor into a high voltage electrical pulses of at least 14,000 volts across said electrodes.

7 more elements

Dependencies are inferred from the claim text.

Reliable, modular, production quality narrow-band high rep rate F.sub.2 laser

Life of this patent

Reliable, modular, production quality narrow-band high rep rate F.sub.2 laser

Life of this patent

Abstract

Claims37