JP2005524998A5

JP2005524998A5 -

Info

Publication number: JP2005524998A5
Application number: JP2004504358A
Authority: JP
Filing date: 2003-04-23
Publication date: 2006-06-15
Anticipated expiration: 2023-04-23

Claims

A modular high fluence high repetition rate ultraviolet laser system for a production line machine,
A) 1) a) a first laser gas;
b) a first pair of spaced apart electrodes forming a discharge region;
A first discharge chamber comprising:
2) When operating at a repetition rate in the range of at least 2,000 pulses / second, after each pulse substantially all of the ions generated by the discharge are removed from the first discharge before the next pulse. Gas circulation means for generating a sufficient gas velocity of the first laser gas in the first discharge region for removal from the region;
3) a heat exchanger system capable of removing thermal energy from the first laser gas to maintain the laser gas temperature within a desired range;
4) Supply sufficient electrical pulses to the first electrode pair to generate a pulse energy greater than 10 mJ and an average pulse intensity greater than 1 × 10 ⁻⁶ watts / cm ² at a location immediately downstream of the discharge region. A laser source for generating ultraviolet laser light at a wavelength of less than 200 nm comprising:
B) a pulse energy density reducing optical component having at least one crystalline fluorine optical component for reducing the pulse energy density to less than 25 × 10 ⁻⁶ J / cm ³ ;
A system comprising:

The system of claim 1, wherein the laser pulse immediately downstream of the discharge region has an average pulse intensity greater than 1.8 × 10 ⁶ watts / cm ² .

The system of claim 1, wherein the pulse energy density reducing optical component comprises at least one crystalline fluorine optical component enclosed in a containment chamber containing fluorine gas.

4. The system of claim 3, wherein the dilator is enclosed in a downstream containment chamber downstream of the first discharge chamber.

The system of claim 3, wherein the at least one crystalline fluorine optical component comprises at least one prism beam expander.

The system of claim 3, wherein the fluorine gas is a gas mixture and occupies less than 0.1 percent of the mixture.

The system according to claim 1, further comprising a second discharge chamber and an optical component for generating amplification seed light in the first discharge region.

The system according to claim 4, wherein the downstream enclosure is purged with a purge gas containing fluorine.

The fluorine system according to claim 8, characterized in that it is in the form of F ₂ gas.

9. The system of claim 8, wherein the fluorine is in the form of a gas molecular compound that includes fluorine.

The molecular compound is NH ₄ F.I. _{_{HF, SF 6, CCl 3 F}} , C 2 C1 2 F 4, SiF 4, SF 4, NF 3, and the system of claim 8 that wherein is selected from the group consisting of COF _2.

The system according to claim 11, wherein the molecular compound is SiF ₄ .

The SiF ₄ is contained in the mixture with helium, the SiF ₄ concentration system according to claim 12, characterized in that 1.0ppm or more.

The system of claim 1, wherein the crystalline fluorine optical component comprises a protective coating to prevent surface damage caused by intense ultraviolet laser pulses.

The system of claim 14, wherein the coating comprises trapped fluorine atoms.

The system of claim 14, wherein the coating comprises fluorine silicon oxide.

In the crystalline fluorine optical component, the first surface is exposed to fluorine gas, the second surface is not exposed to fluorine gas, the protective coating is applied to the second surface, and the first surface is exposed to the first surface. The system according to claim 14, wherein the system is not applied.

The system of claim 1, wherein the crystalline fluorine optical component comprises MgF ₂ .

The system of claim 1, wherein the at least one crystalline fluorine optical component comprises a CaF ₂ prism beam expander disposed within a laser chamber window housing.

The pulse energy density reducing optical component includes an optical component for focusing the seed light in the vicinity of the first end of the first discharge region, and is expanded while being amplified in the final pass through the discharge region. The system of claim 7, wherein the system is adapted to generate a beam.

The system of claim 1, wherein the at least one crystalline fluorine optical component comprises a two-prism CaF ₂ beam expander for enlarging the beam cross section by a factor of four.

The system comprises at least one CaF ₂ crystal window cut such that laser light traverses the window along a <100>, <010>, or <001> direction, the window having a polarization plane 2. The system of claim 1, wherein is clocked to be parallel to one of the <100>, <010>, or <001> directions.

All CaF ₂ and MgF ₂ optical components used to manipulate the laser light exiting the first discharge region are clocked to determine their birefringence as a function of clock position prior to installation, The system according to claim 1, wherein the system is mounted at a position selected so as to minimize polarization rotation of the laser light.

At least one TIR rotating prism and at least one beam reversing prism, each of which has the laser light in at least two directions along a crystal axis in a <100>, <010>, or <001> direction. The system of claim 1, wherein the system is oriented across each of a TIR rotating prism and a beam reversing prism.

8. The system of claim 7, wherein the pulse stretcher comprises a beam splitter and four mirrors, two focusing mirrors and two collimating mirrors.

The beam splitter is CaF ₂ having front and rear cuts parallel to the (100), (010), (001) crystal planes, and the beam splitter is each of the laser light that traverses the beam splitter. 26. The system of claim 25, wherein a partial propagation plane is oriented across the beam splitter parallel to a (100), (010), or (001) crystal plane.

The apparatus further comprises a line width narrowing unit for narrowing a spectral bandwidth of the laser light generated in the second discharge chamber, the line width narrowing unit comprising a multiple prism beam expander, and the multiple prism beam. Each prism in the dilator comprises at least one surface cut of a (100), (010), or (001) crystal plane and traverses from the second discharge chamber toward the line narrowing grating 8. The system of claim 7, wherein is oriented to exit the prism substantially perpendicular to the (100), (010), or (001) plane.

The system of claim 1, wherein the first discharge chamber comprises a window of C-cut MgF ₂ that is clocked to determine a clock position that results in minimal polarization rotation.

The prism further includes at least one uniaxial birefringent crystal prism, and the C-axis of the prism is oriented so that the incident beam direction is orthogonal to the C-axis, and the polarization state of the incident beam is on the incident surface of the prism. The system of claim 1, wherein the system is P-polarized or S-polarized.

The system of claim 1, further comprising beam profile flip means for reducing laser light coherence.

At least one of the crystalline fluorine optical components comprises a UV light-blocking protective coating applied to a surface in contact with the degradable material subject to UV degradation, the protective coating protecting the degradable material from UV irradiation The system according to claim 1.

Said protective coating is selected from the group consisting of Al ₂ O _3, SCO _2, The system of claim 31 wherein the degradable material, characterized in that an epoxy resin or O-ring.

The optical element monitor having a thermocouple attached to the optical element is further provided, and an optical element defect is detected by detecting an abnormal temperature rise of the optical part. The described system.