Laser-Produced Sn-plasma for Highvolume Manufacturing EUV Lithography

Transcription

1 Panel discussion Laser-Produced Sn-plasma for Highvolume Manufacturing EUV Lithography Akira Endo * Extreme Ultraviolet Lithography System Development Association Gigaphoton Inc * 2008 EUVL Workshop 11 June, 2008 Wailea Marriott Hotel, Hawaii Ver. 1.0 Acknowledgments This work was supported by the New Energy and Industrial Technology Development Organization -NEDO- Japan. 1

2 Requirement for HVM High EUV power >115 W EUV Stability Collector mirror lifetime Low CoG / CoO Light Source Concept CO2 laser + Sn microdroplet + Magnetic field plasma guide Sn target supply High power pulsed CO 2 Laser at 100kHz IF Magnetic field plasma guiding Sn collector LPP: Laser-Produced Plasma 2

3 Advantages LPP Laser Produced Plasma Scalable through laser repetition rate (>100kHz) and pulse energy (>200mJ) High repetition rate provides advantage for dose control Small source size (0.1mm) more efficient collection, reduces the complexity of optical systems designs Mass limited operation minimum Sn injection leads to no generation of debris Isolated Plasma Long distanced between hot plasma and chamber components Magnetic plasma guiding for full Sn recovery Normal incidence collector spectral filter, low obscuration, easier to cool 3

4 Wavelength dependence of EUV emission Conversion efficiency dependence on the laser intensity Target material : Sn plate 10.6um 1.064um intensity [a.u.] CE: 2.5% - 4.5% with CO2 laser Laser intensity 3x10 10 W/cm 2 *energy:30mj *Pulse width:11ns *Spot size: d=100um Target material : Sn wire wavelength [nm] CO2 Nd:YAG EUV spectra from Sn plasma Narrow in-band spectrum with CO2 laser 4

5 CE vs Nd:YAG and CO2 Lasers CE vs cavity depth Cross section of cavity EUV CE (%) CO 2 Nd:YAG Cavity depth (μm) Laser ablation CO 2 laser CE % experimentally confirmed mechanical 5

6 EUV CE and spectrum EUV spectrum Intensity (arb. units) CE 4% Cavity Planar Wavelength (nm) Plasma image (VIS) CE 2% EUV Pulse shape Intensity (arb. units) CE 4% Time (ns) Cavity(200um) Cavity(100um) Planar Planar Cavity100 Cavity200 CE 3% CE 2% CO 2 laser target 0.5 mm CE increased with cavity depth 6

7 Electron density profile Hot dense plasma Electron density n c X-ray emission Laser Laser plasma interaction region n c 2 ε0mω = 2 e (e / cm = λ ( μm) n c 2 3 ) 0 Distance 7

8 Pre-plasma optimization Single 2X10 11 W/cm2, 20ns pulse Dr.Sunahara Double pulse 1X10 9 W/cm2, 20ns pulse Sn 100um F=30,d= Te 60 n i (cm -3 ) ni Seff EUV PL Te < Z > T e (ev), < Z > n i (cm -3 ) ni OD=1 PL Seff EUV < Z > T e (ev), < Z > Position (μm) OD= Laser abs. fraction 46% 91% X-ray CE 48% 69% EUV CE 3.3% 7.2% Position (μm) 8 28/30

9 Theoretical Prediction Dr.Sunahara 10 Double 10ns (2D) Pre-pulse 1X10 8 W/cm 2 10ns(0.53m conversion efficiency (%) Double pulse 20ns (1D) Single CO2 irradiation 20ns(1D) Double 20ns (2D) Double 40ns (2D) Time delay :180ns In 2D simulation, 150m pre-formed plasma is initially set. Laser spot diameter: 800 m laser intensity (W/cm 2 ) 9 29/30

10 High power CO2 laser MOPA system Laser Power 13 kw Pulse Width 20 ns Repetition Rate 100 khz Beam quality : M2 1.1 Pulse energy stability : 2% (3s, 500 pulses) Laser System 60W 3 kw 13 kw Oscillator Wave length: 10.6um Rep. rate :100kHz Pulse width :20 ns (FWHM) Pre-Amplifier RF-excited CO2 laser Main-Amplifier RF-excited CO2 laser 100 W at I/F equivalent Laser beam profile 10

11 Average power increase in the last two years Now 08 May Laser power [kw] 06 Feb. 06 Oct. 06 Dec. 07 Feb. 07 Oct. 11

12 20 kw Short Pulse CO 2 laser MOPA system AMP1 RF-excited CO2 laser Pumping : 50 kw 20 kw (200mJ at 100kHz) Multi-line Oscillator Rep. rate :100kHz pulse width :20 ns (FWHM) AMP2 RF-excited CO2 laser Pumping power : 120 kw AMP3 RF-excited CO2 laser Pumping power : 120 kw Single beam, 20 kw CO 2 laser system in sight Power Limitation Damage of Optics Diamond window Filling Factor Compensation of beam diffraction and thermal lensing Saturation Broadband amplification 12

13 Magnetic field plasma beaming 1) Investigation of Tin ion flux in Real 3D-space 2) Optimization of Tin debris evacuation. magnet diameter = 1500mm Chamber diameter = 600mm magnet field flux (center) ~ 3.0T magnet field flux (plasma) ~ 2.0T 13

14 Magnetic field plasma beaming Superconducting magnet was installed for: 1) Investigation of Tin ion flux in Real large space. 2) Optimization of Tin debris evacuation. Visible image of Sn plasma flow in magnetic field Laser : CO2 laser, Target : Sn plate Without magnetic field Magnetic flux density : 2T 14

15 Results on symmetry axis with & w/o B-field Approx. 6mm40mm 2T 6mm 0 CO2 laser Witness plate Witness plate Sn plate 0T Tin ions are effectively confined and guided by magnetic field. 15

16 Ion flux with/without B-field 22.5deg CO2 laser 7.5deg Faraday Cup 16

17 Magnetic field plasma guiding Nanopowder Low Deposition No deposition 37.5 Dendolite Strong deposition Etching Erosion CO2 laser 22.5 Sn plate 52.5 No deposition 67.5 No deposition 17

18 Neutral particle generation with Nd:YAG and CO2 lasers Dr Furukawa 15ns laser irradiation on planar Sn target Full ionization during laser irradiation 18

19 Gigaphoton LPP Light Source - Sn Droplet - High power pulsed CO2 laser - Magnetic-field Plasma Guiding Sn supply Magnet Plasma IF CO2 laser Collector mirror Sn collector 19

20 EUV LPP light source roadmap ETS (Internal use only) SD (1 st Gen.) (proto/ integration possible) HVM(2 nd Gen.) (product) Timing 2009/1Q 2009/4Q 2011/1Q Power (Source to IF:34% (R=0.6, 4sr(0.64), T=0.9) 100W 140W 280W Drive laser 10kW 10kW 20kW CE 3.5% 4.0% 4.0% Target Tin droplet Tin droplet Mitigation Single magnet & ionization C1 Mirror Spec. 4sr 60 Bi-layer R>60% magnet & ionization TBD Heat Protected TBD Life 200Bpls TBD TBD Tool interface (I/F) No Yes Yes Duty >75% TBD TBD 20

21 Power roadmap Today to SD Non commercial system Commercial system Power at IF (W) W (HVM:2 nd generation) W (Today) 100W (ETS) 140W (SD:1 st generation) 07Q1 08Q1 09Q1 10Q1 11Q1 12Q1 140W will be available in 2010 & 280W in

22 Summary LPP technology is ready for HVM Further advance of component technology Laser power 13 kw obtained; 100 W in-band EUV at I/F equivalent. scalable to 20 kw. Optimized Sn target for high CE 4% (achieved) and 8%(predicted). Magnetic field plasma guiding of CO 2 laser produced Sn plasma. Sn neutral generation reduced by magnetic field. Sn plasma is guided by magnetic field. Basic technology for full Sn evacuation is established. Integrated operation Integrated system demonstration with advanced component technology and mirror lifetime evaluation. 22