METHOD AND APPARATUS FOR IMMERSION GRATING LITHOGRAPHY

1 . An immersion grating assembly, comprising:

at least one optical grating including at least one grating structure and at least one grating diffractive surface, the at least one optical grating configured to be positioned in a Littrow or near-Littrow configuration and provide optical dispersion for ultraviolet light;

at least one prism formed from at least one UV-transmitting material with at least a first index of refraction, the at least one prism having a first prism surface and at least one second prism surface;

at least one immersion medium with at least a second index of refraction, the at least one immersion medium disposed between the at least one second prism surface and the at least one grating diffractive surface, wherein the first index of refraction of the at least one prism and the at least one second index of refraction of the at least one immersion medium are substantially equal and wherein the at least one immersion medium is substantially transmissive at wavelengths less than about 300 nanometers;

at least one retaining structure configured to confine and retain the at least one optical grating and the at least one immersion medium and prevent the at least one immersion medium from absorbing contamination and moisture; and

at least one bonding agent configured to bond the at least one prism to at least one surface of the at least one retaining structure.

2 . The immersion grating assembly of claim 1 , wherein the at least one immersion medium is substantially transmissive at wavelengths between about 100 nanometers and about 450 nanometers.

3 . The immersion grating assembly of claim 1 , wherein the at least one immersion medium is substantially transmissive at wavelengths between about 300 nanometers and about 400 nanometers.

4 . The immersion grating assembly of claim 1 , wherein the at least one immersion medium is substantially transmissive at wavelengths below about 250 nanometers.

5 . The immersion grating assembly of claim 1 , wherein the at least one immersion medium is substantially transmissive at wavelengths below about 200 nanometers.

6 . The immersion grating assembly of claim 1 , wherein the at least one immersion medium is substantially transmissive at wavelengths below about 150 nanometers.

7 . The immersion grating assembly of claim 1 , wherein the at least one immersion medium is a fluid.

8 . The immersion grating assembly of claim 6 , wherein the at least one immersion medium is a glycerol-water mixture.

9 . The immersion grating assembly of claim 1 , wherein the at least one immersion medium is an adhesive.

10 . The immersion grating assembly of claim 1 , wherein the at least one immersion medium is a viscous pre-form.

11 . The immersion grating assembly of claim 1 , wherein the index of refraction of the at least one immersion medium is higher than the index of refraction of the at least one prism.

12 . The immersion grating assembly of claim 1 , wherein the index of refraction of the at least one immersion medium is lower than the index of refraction of the at least one prism.

13 . An immersion grating assembly, comprising:

at least one optical grating including at least one grating structure and at least one grating diffractive surface, the at least one optical grating configured to be positioned in a Littrow or near-Littrow configuration and provide optical dispersion;

at least one prism formed from at least one optically transmitting material with at least a first index of refraction, the at least one prism having a first prism surface and at least one second prism surface;

at least one immersion medium with at least a second index of refraction, the at least one immersion medium disposed between the at least one second prism surface and the at least one grating diffractive surface, wherein the first index of refraction of the at least one prism and the at least one second index of refraction of the at least one immersion medium are substantially equal and wherein the at least one immersion medium is substantially transmissive at wavelengths between about 300 nanometers and about 800 nanometers;

at least one retaining structure configured to confine and retain the at least one optical grating and the at least one immersion medium and prevent the at least one immersion medium from absorbing contamination and moisture; and

at least one bonding agent configured to bond the at least one prism to at least one surface of the at least one retaining structure.

14 . The immersion grating assembly of claim 13 , wherein the at least one immersion medium is substantially transmissive at wavelengths between about 300 nanometers and about 450 nanometers.

15 . The immersion grating assembly of claim 13 , wherein the at least one immersion medium is substantially transmissive at wavelengths between about 450 nanometers and about 600 nanometers.

16 . The immersion grating assembly of claim 13 , wherein the at least one immersion medium is substantially transmissive at wavelengths below about 600 nanometers and about 780 nanometers.

17 . The immersion grating assembly of claim 13 , wherein the at least one immersion medium is a fluid.

18 . The immersion grating assembly of claim 17 wherein the at least one fluid is a glycerol-water mixture.

19 . The immersion grating assembly of claim 13 , wherein the at least one immersion medium is an adhesive.

20 . The immersion grating assembly of claim 13 , wherein the at least one immersion medium is a viscous pre-form.

21 . The immersion grating assembly of claim 13 , wherein the index of refraction of the at least one immersion medium is higher than the index of refraction of the at least one prism.

22 . The immersion grating assembly of claim 13 , wherein the index of refraction of the at least one immersion medium is lower than the index of refraction of the at least one prism.

23 . A method of manufacturing an immersion grating assembly, comprising:

selecting at least one optical grating having at least one grating structure and at least one grating diffractive surface, the at least one optical grating configured to be positioned in a Littrow or a near-Littrow configuration and to provide optical dispersion for ultraviolet light;

selecting at least one prism formed from at least one UV-transmissive material with at least a first index of refraction, the at least one prism having a first prism surface and at least one second prism surface, the at least one prism having at least a first index of refraction;

optically contacting the at least one grating diffractive surface to the at least one second surface of the prism using at least one immersion medium with at least a second index of refraction, such that reflections between the at least one second surface of the prism and the at least one grating diffractive surface are minimized;

installing the at least one optical grating and the at least one immersion medium within at least one retaining structure, the at least one retaining structure configured to prevent the at least one immersion medium from absorbing contamination and moisture; and

bonding the at least one prism to at least one surface of the at least one retaining structure with at least one bonding agent.

24 . The method of claim 23 , further comprising tuning the wavelength of peak dispersion efficiency of the at least one grating assembly by selectively changing the index of refraction of the at least one immersion medium.

25 . A method of line-narrowing an excimer laser, comprising;

supplying at least one immersion grating assembly in optical communication with at least one excimer laser gain medium, wherein the at least one immersion grating assembly is configured to provide angular dispersion to at least one first light beam having at least a first central wavelength and at least a first spectral linewidth;

directing the at least one first light beam from the at least one excimer laser gain medium to the at least one immersion grating assembly;

diffracting the at least one first light beam with the at least one immersion grating assembly such that at least a second light beam with at least one second central wavelength is reflected back in substantially the opposite direction to, and substantially parallel to, the direction the at least one first light beam came from;

providing at least one aperture configured to allow only the at least one second light beam to propagate back into the at least one excimer laser gain medium; and

amplifying the at least one second light beam in the at least one excimer laser gain medium and outputting at least one emitted light beam with at least a second spectral bandwidth centered around the at least one second central wavelength of the at least one second light beam, wherein the at least one second spectral linewidth of the at least one emitted light beam is less than the at least one first spectral linewidth of the at least one first light beam.

26 . A method of excimer laser lithography:

providing at least one excimer laser, at least one the excimer laser in optical communication with at least one line narrowing module, wherein the line narrowing module comprises at least one immersion grating assembly configured to narrow the spectrum of at least one light beam emitted by the at least one excimer laser;

directing the at least one light beam emitted by the at least one excimer laser to at least one optical system configured to condition the light beam;

directing the conditioned light beam to at least one mask or reticle, the at least one mask or reticle being configured to provide patterned light; and

directing the patterned light through at least one projection lens to at least one semiconductor wafer.