Dual-Wavelength Driver and Bragg Mirror for EUV Lithography Tool

1. The two pulses two wavelength driver of EUV radiation LPP source and of 4M Bragg mirror objective for laboratory EUV Lithography tool:Development of the ISTC project #3857R.Seisyan, A.Zhevlakov, M.Sasin A.F.Ioffe Physical Technical Institute of Russian Academy of Sciences, St.-Petersburg, Russiae-mail: rseis@ffm.ioffe.ru

2. “Key Technologies of EUV-nanolithography System of Super high Resolution on the Base of High Effective LPP Source” February 2009 – February 2012 Project Budget – 317,501 € = $492,700 executors: Ioffe Institute and Institute for Laser Physics, both Saint-Petersburg, Russia ISTC project # 3857

3. Gerry O’Sullivan, John Costello, Torsten Feigl, Peter Choi, Ladislav Pina, all COST MP0601 participants Collaborators of the Project

4. Calculation and design of dual-wavelength (λ = 1.06 μm and λ = 10.6 μm) laser- optical scheme forming focal spot on the target at double-pulse illumination. Calculation and design of 4-mirror wide-aperture imaging objective with enlarged image area. Precise mechanical and optical systems development providing for nanometric scale precision for adjustment and focusing of nanolithographer optical system. Placing of the optical and mechanical systems in existing body of NL tool, designed and partly manufactured in the frame of ISTC project #0991. ISTC project #3857,the first year Work Plan

5. Experimental nanolithographer of Ioffe Institute in the making (2006)

6. View of the experimental hall with the dustless room (center and right) and prototype excimer laser (on the left) used in the Experimental Stand work

7. The main ideas used in the SYMER source (as well as in GIGAPHOTON source) are the following. Target material should be Sn (liquid Sn droplets) The main primary laser should be pulsed powerful (about 15-20kW) CO2 laser The main ways to solve debris mitigation problem are the use of magnetic field and The use of inert gas curtain The main ideas of the industrial EUV LPP source

10. Advanced LPP source for NL tool

11. Cross-section of string source

12. The “String” EUV Source cross-section Collector mirror Magnets String target unit String To an objective, samples, etc..

13. “String” EUV target with different laser wavelength ignition and heating UV laser pulse Hot, radiating EUV plasma Ionised Tin, “cold” plasma 10μ laser pulse: heating Capillary String covered with tin Gas pulse for debris mitigation

14. Former design of dual-wavelength (λ = 1.06 μm and λ = 10.6 μm) laser-optical scheme forming focal spot on the target at double-pulse illumination. 10 mm H2 cell 1930 nm CO2 laser Optical parametrical oscillator Objective 10 mm 532 nm 2-nd harmonic generator Objective 1064 nm Optical delay line, 1-200 ns 1064 nm YAG:Nd+3 , 1064 nm 1.5 J, 8 ns, 10 Hz

15. Resultingdual-wavelength (λ = 1.06 μm and λ = 10.6 μm) laser-optical scheme forming focal spot on the target at double-pulse illumination

16. Possible amplification of 6 pass CO2 laser driver (1ns initial pulse) 10 4 2 Энергия, Дж 1 3 1 0.1 0.01 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 Эффективный радиус пучка, см Calculation of CO2 laser driver

17. Multipass scheme for amplifier based on CO2 laser “Fialka” L 2 1 Rm Multipass scheme of CO2 amplifier

18. Experimental Lithographer (EN) made in Ioffe Institute

19. 1233.66 mm EN optical scheme Coupling system Mask Lens Collector 99.9 Plasm EUV Spectrograph EUV Detector Correction & Filter Mirror 1256.2 mm Screen SecondObjectiveMirror FirstObjectiveMirror First Mirror Sample

20. Bragg mirror imaging systems with high resolution NA=0,06 – 0,09 NA=0,36 NA=0,1 – 0,14 NA=0,485

21. Image modeling L&S 30 nm, contrast 60% L&S 45 nm, contrast 97% L&S 15 nm, contrast 58%

22. Four mirror objective Results of mathematical modeling of microstructures. The image of corners with width of a line 10 nm in the centre of a field

23. The specification of the objective The numerical aperture 0.485 The resolution 10 nmwith contrast 0.26 20 nm with contrast 0.35 The sizes of the field of the image 0.27x0.27 mm2 → 2.0x2.0mm2 The central shielding 0.407 The distance from a mask up to a plane of the image 829 mm Root mean square wave aberration on the field of the image 0.0573 - 0.1181 The limiting resolution 68000 mm with contrast 0.02 The magnification of the objective 12

25. Scheme of nanolithograph Coupling system Mask Lens Collector Plasm EUV Spectrograph EUV Detector Correction & Filter Mirror SecondObjectiveMirror Fourth ObjectiveMirror FirstObjectiveMirror Third ObjectiveMirror Sample First Mirror 27

26. z Base unit b incoming incoming beam q beam q b d h d a grating 0 grating 0 q q 0 order 0 order -1 order +1 order Lens O O grating 1 grating 1 Principal scheme of focusing and alignment system Grating pattern must besuch thatsuppress the second order of diffraction.

28. An original technology for photomask production is developed in the Ioffe Institute for the EN. It includes originally invented mask pattern and construction, and technologies for deposition both reflecting and absorbing structures on the mask surface. The focusing and alignment systems represent by itself multichannel interferometers using gratings and second harmonics solid state laser projection device.

29. Scheme of the focusing system realization

31. The EN modules are installed on massive granite plate of vibroprotective table. The table has been invented in the Baltic University (St. Petersburg) and later finished off in conformity with the EN needs. The table has high performance characteristics and provides both passive and active vibroprotection including infralow frequencies. Vibroprotective table

32. Piezopositioners

33. Phenomenological modelof the non-linear photoresist

34. Estimated parameters of inorganic nonlinear photoresists Sensitivity: C = 3×10-3 cm3/J, threshold intensity: Ith = 1.7×104 W/cm2, threshold diffusion width: δ = 8.5×103 W/cm2. Dose of H = h/C = 1.7 mJ/cm2 is sufficient for exposure of a photoresist specimen h=50-nm thick. Pulse threshold dose (at 20 ns) is Hth = τIth = 0.34 mJ/cm2. Thus, the necessary dose is accumulated with 5 pulses at the threshold intensity and 20 ns pulse duration.

35. Computer simulation of the enhancement of the contrast by means of inorganic non-linear photoresist

36. Experiments on the EUV exposure have been carried out with synchrotron 13.4nm emission and, in a tentative form, on the Experimental Stand, the auxiliary setup of the Ioffe Institute, for λ = (13.4 ± 0.3) nm. The results obtained suggest that the EUV sensitivity should be some lower than that at λ = 193 nm. As2S3 films exposed on the synchrotron, after the chemical development, demonstrated distinct interferention structure with 30-40 nm stripes and space-stripe period about 50-100 nm thereby confirming good resolution ability of the material.

37. QD semiconductor laser QDC (quantum dot crystal) Interference transistor Single-electron transistor DFB Laser systems Mesoscopic elements Photon crystals Мезоскопические элементы