High Brightness EUV Light Source System Development for Actinic Mask Metrology

Transcription

1 High Brightness EUV Light Source System Development for Actinic Mask Metrology Peter Choi, Sergey V. Zakharov, Raul Aliaga-Rossel, Aldrice Bakouboula, Otman Benali, Philippe Bove, Michèle Cau, Grainne Duffy, Carlo Fanara, Wafa Kezzar, Blair Lebert, Keith Powell, Ouassima Sarroukh, Luc Tantart, Clement Zaepffel, Vasily S. Zakharov, Alan Michette*, Edmund Wyndham** NANO UV sas EPPRA sas * Dept of Physics, King s College, London, UK ** Pontificia Universidad Catolica de Chile

2 OUTLINE Remaining focus areas for EUVL deployment Plasma radiation sources for mask inspection Multiplexed source for high power & brightness Nano-UV: EUV and soft X-ray source unit source characteristics charge energy scan in comparison with predictions Multiplexed high brightness EUV sources HYDRA 4 ABI HYDRA 12 AIMS HYDRA - APMI

3 EUV (13.5nm wavelength) lithography chosen for nano features microchip production HP NOW EUV for 22 nm HVM EUV source for HVM & actinic mask inspection - a key challenge facing the industry

4 Remaining Focus Areas EUVL Symposium, Tahoe Long-term source operation with 100 W at the IF and 5 megajoule per day EUVL Symposium, Prague Mask yield & defect inspection/review infrastructure 2 - Availability of defect-free masks, throughout a mask lifecycle, and the need to address critical mask infrastructure tool gaps, specifically in the defect inspection and defect review area Long-term source operation with 115 W at the IF for 5mJ/cm 2 resist sensitivity or with 200W at the IF for 10mJ/cm 2 resist sensitivity light source for Litho and mask inspection critical -

5 Actinic Mask Inspection - key source requirements based on current studies Source 2009 Baltimore High brightness, small etendue, high repetition rate, and clean light source is preferable

6 Multiplexing - a solution for high power & brightness Small size sources, with low enough etendue E 1 =A s Ω << 1 mm 2 sr can be multiplexed. The EUV power of multiplexed N sources is P EUV E N Ω τ The EUV source power meeting the etendue requirements increases as N 1/2 This allows efficient re-packing of radiators from 1 into N separate smaller volumes without losses in EUV power f EUV Radiance, MW/mm2 sr tin Z* Scan Mass Depth (rho*r), g/cm2 R=0.04mm R=0.08mm R=0.16mm R=0.31mm R=0.625mm R=1.25mm R=2.5mm R=5mm Spatial-temporal multiplexing: The average brightness of a source and output power can be increased by means of spatial-temporal multiplexing with active optics system, totallizing sequentially the EUV outputs from multiple sources in the same beam direction without extension of the etendue or collection solid angle - compct physical size of SoCoMo?

7 Nano-UV: Current Product Development Generic Source Products high brightness unit source - CYCLOPS -B high brightness multiplexed source - HYDRA -B high power multiplexed source - HYDRA -P Research Metrology Products Nano-patterning Resists Exposure Tool - GeNI Soft X-ray In Vitro Microscope - McXI EUV Mask Inspection Microscope - McEUVI

8 Nano-UV: High Brightness EUV Source micro-plasma pulsed capillary discharge Typical Operating Conditions & Measured Performance use SXUV20 Mo/Si filtered diode (IRD) 3 nm EUV band (12.4 nm nm) (110 nm) Al on Si 3 N 4 (50 nm) to reject OoB discharge in He/Ar & He/Ar/Xe admixture electrical stored energy J kv, 1-3 khz operation radiation pulse < 40 ns irradiance measured at different distances EUV power at beam spot - > 3 W at 1 khz plasma can be optimized for high power or high irradiance typical etendue to mm 2.sr V=25.4kV ( 1.24nF) EUV diode Discharge Voltage Spot-scan spatial profile Photodiode signal (mv) Maxpulse B Data: Data1_Maxpulse Model: Gauss Distance (mm) GEN-II CYCLOPS cells Chi^2/DoF = R^2 = y ± xc ± w ± A ± HIGH POWER Mode Irradiance 3.5 W/cm 2 at 50 cm from plasma source Delivered Power is 3.9 W over a 16 mm 1 khz

9 Source Characteristics I - irradiance vs stored energy Measurement parameters - Average mode over 128 shots: - 1.6mm diameter capillary - working pressure P =20mtorr - He:Ar:Xe mixture - distance between diode and the capillary=50cm - operating frequency = 1 khz - diode quantum 13.5nm=1.4e/ph - diode filter transmission band = 3nm ( nm) Irradiance at the profile maximum (x 10e17 ph/cm2/s) Energy scan experiment (in 3nm band) EUV In-band energy EUV energy per shot, per shot, μ J mj Stored energy (J) Stored energy, mj Energy scan calculated (in 2% band)

10 Source Characteristics II Optimization Measurements - filtered IRD diodes on translation stages at 3 axial positions from the radiation source - transverse scan to obtain radiation profile and irradiance - Gaussian envelope fit to calculate power - use 1/e 2 beam spot diameter measured and beam expansion angle to estimate etendue - 21 kv operation at 1 khz, He-Ar admixture - at 62 cm radiation (3nm band) peak irradiance = 6.4 W/cm 2 power in spot = 2.2 W beam FWHM = 5.8 mm etendue < 7 E-3 mm 2. sr (max) etendue and power 75cm Cyclops Photodiode signal (V) Average over 128 shots V break 62 cm from source 35mtorr (He:Ar) int(v(t)dt)= 127nVs τ=54ns N ph =4.36 e17 ph/cm 2 /s Time (ns) Diode signal at peak Photodiode signal (V) Maxpulse B Data: A62cm_Maxpulse Model: Gauss Chi^2/DoF = R^2 = y ± xc ± w ± A ± FWHM 5.8mm Distance (mm) Scanned signal profile Radial distance (mm) HWHM linear fit beam expansion Half angle =0.30 solid angle= 8.8e-5 sr Axial distance from the capillary (mm) HWHM obtained at 3 locations

11 Source Characteristics III - wavefront measurement HASO X EUV Shack Hartmann wavefront sensor (manufactured by Imagine Optic) EUV source HASO 1890 mm EUV beam diameter d= 9.75 mm at R=1890 mm from source Beam divergence half angle 0.19 Solid angle: Ω = msr Acquired image 60s exposure, source at 1 khz Derived wavefront 166 nm RMS (12 λ) & (root-mean-square deviation) 760nm PV (58 λ) (peak to valley) * With support of G. Dovillaire, E. Lavergne from Imagine Optic and P. Mercere, M.Idir from SOLEIL Synchrotron

12 EUV Source Product GEN II emission characteristic stability test Photodiode signal (V) Discharge voltage (kv) The emission-voltage discharge characteristic enables one to correct the radiation output level and to control the dose stability

13 HYDRA -ABI - spatial multiplexing for blank inspection Design Specifications 60 W/mm 2.sr in band 2% EUV radiant brightness at the IF 0.6 W at the IF etendue 10 2 mm 2.sr source area 31 mm 2 / TBD optimized for mask blank inspection 4x i SoCoMo units working at 3 khz each no debris / membrane filter close packed pupil fill Current Status 4 units integration & characterization single unit optimization ML mirrors evaluation & modelling

14 HYDRA 4 -ABI - pupil arrangements Radiation observed on a fluorescent screen 70 cm downstream ALL 4 Sources Source 1 only Source 2 only Source 4 only Source 3 only 25 mm All 4 sources aligned to a point without use of any solid optical collector Each source turned on separately and aligned to a different corner

15 HYDRA -AIMS - spatial multiplexing with variable σ Design Specifications 100 W/mm 2.sr in band 2% EUV brightness 2.4W at the IF etendue mm 2.sr (50% fill pupil) source area 4mm 2 / variable σ optimized for aerial image measurements 12x i SoCoMo units, 5 khz working each no debris / membrane filter variable pupil fill and σ Current Status system characterization single unit optimization ML mirrors modelling curved ML plane ML

16 HYDRA 12- AIMS - prototype system A EUV Source for Mask Metrology

17 The Cross Talk Test 2 Cells operation 20KV ; 1 KHz Operation Alignment on SUXV 5 Photodiode Intentionally off axis Cell 1 Pulse discharge Photodiode By intentionally off axis the beam light of cell 1 No impact on the Beam Light of Cell2 Multiplexing sources Choice is proven as agile approach to reduce cost

18 HYDRA -APMI - unique temporal & spatial multiplexing Design Specifications 1200 W/mm 2.sr in band EUV radiant brightness 2.4 W at the IF etendue mm 2.sr source area 20 mm 2 optimized for patterned mask inspection 8x i SoCoMo units working at 3 khz each 24 khz temporally multiplexed no debris / membrane filter Gaussian output spot Current Status optics design & modelling single unit optimization mechanical design

19 HYDRA - metrology sources - ROADMAP

20 Acknowledgements Collaborators Pontificia Universidad Catolica de Chile RRC Kurchatov Institute, Moscow, Russia Keldysh Institute of Applied Mathematics RAS, Moscow, Russia University College Dublin King s College London Sponsors EU & French Government ANR- EUVIL OSEO-ANVAR RAKIA EUV LITHO, Inc.

21 HYDRA Ultra high brightness modular construction small foot print low cost of ownership adaptable to user needs A New Technical Capability Arising