Direct photo-etching of poly"methyl methacrylate… using focused extreme ultraviolet radiation from a table-top laser-induced plasma source

In order to perform material interaction studies with intense extreme ultraviolet (EUV) radiation, a Schwarzschild mirror objective coated with Mo/Si multilayers was adapted to a compact laser-based EUV plasma source (pulse energy 3 mJ at λ=13.5 nm, plasma diameter ∼300 μm). By 10× demagnified imaging of the plasma a pulse energy density of ∼75 mJ∕cm2 at a pulse length of 6 ns can be achieved in the image plane of the objective. As demonstrated for poly(methyl methacrylate) (PMMA), photoetching of polymer surfaces is possible at this EUV fluence level. This paper presents first results, including a systematic determination of PMMA etching rates under EUV irradiation. Furthermore, the contribution of out-of-band radiation to the surface etching of PMMA was investigated by conducting a diffraction experiment for spectral discrimination from higher wavelength radiation. Imaging of a pinhole positioned behind the plasma accomplished the generation of an EUV spot of 1 μm diameter, which was employed for direct...

[1]  Libor Juha,et al.  Strong temperature effect on X-ray photo-etching of polytetrafluoroethylene using a 10 Hz laser-plasma radiation source based on a gas puff target , 2006 .

[2]  Torsten Feigl,et al.  Formation and direct writing of color centers in LiF using a laser-induced extreme ultraviolet plasma in combination with a Schwarzschild objective , 2005 .

[3]  C. Peth,et al.  Characterization of gas targets for laser produced extreme ultraviolet plasmas with a Hartmann-Shack sensor , 2004 .

[4]  Hiroyuki Niino,et al.  Ablation of silica glass using pulsed laser plasma soft X-rays , 2005 .

[5]  Sebastian Kranzusch,et al.  Spectral characterization of EUV radiation emitted from a laser-irradiated gas puff target , 2001 .

[6]  G. Blanchet Deposition of Poly(methyl methacrylate) Films by UV Laser Ablation , 1995 .

[7]  Tomas Mocek,et al.  Focusing a multimillijoule soft x-ray laser at 21 nm , 2006 .

[8]  Bodil Braren,et al.  Nature of ‘‘incubation pulses’’ in the ultraviolet laser ablation of polymethyl methacrylate , 1990 .

[9]  Libor Juha,et al.  ABLATION OF POLY(METHYL METHACRYLATE) BY A SINGLE PULSE OF SOFT X-RAYS EMITTED FROM Z-PINCH AND LASER-PRODUCED PLASMAS , 2002 .

[10]  Emerging Lithographic Technologies XI , 2006 .

[11]  F. Cerrina,et al.  Extreme ultraviolet and x-ray resist: Comparison study , 1999 .

[12]  N. Kaiser,et al.  EUV multilayer optics , 2006 .

[13]  Elizabeth A. Dobisz,et al.  Emerging Lithographic Technologies V , 2000 .

[14]  E. J. Caine,et al.  Optical data storage in LiF using electron beam encoding , 1998 .

[15]  Bernd Schäfer,et al.  Investigation of the propagation characteristics of excimer lasers using a Hartmann–Shack sensor , 2000 .

[16]  Photoacoustic studies of excimer laser induced ablation of polymethylmethacrylate , 1988 .

[17]  B. Schäfer,et al.  Determination of beam parameters and coherence properties of laser radiation by use of an extended Hartmann-Shack wave-front sensor. , 2002, Applied optics.

[18]  Sebastian Kranzusch,et al.  Spatial characterization of extreme ultraviolet plasmas generated by laser excitation of xenon gas targets , 2003 .

[19]  Uwe Stamm,et al.  Extreme ultraviolet light sources for use in semiconductor lithography—state of the art and future development , 2004 .

[20]  P. Di Lazzaro,et al.  Point defects in lithium fluoride by EUV and soft X-rays exposure for X-ray microscopy and optical applications , 2004, IEEE Journal of Selected Topics in Quantum Electronics.

[21]  Philip Smith,et al.  UV written waveguides using crosslinkable PMMA-based copolymers , 2002, CLEO 2002.