EUV projection optics and active mirror development at SAGEM R. Geyl,, M. Boutonne,, J.L. Carel,, J.F. Tanné, C. Voccia,, S. Chaillot,, J. Billet, Y. Poulard, X. Bozec SAGEM, Etablissement de St Pierre du Perray Avenue de la Tour Maury 9128 St Pierre du Perray,, FRANCE
EUV Programs at SAGEM 2 21 22 23 24 25 26 27 PREUVE BEL TECH. SUP. EXTATIC MORE MOORE?? EXTUMASK See Poster #37 2
SAGEM Contribution to PREUVE SAGEM has manufactured the complete set of optics for the BEL (Banc d Essai de Lithographie) Characteristics x1 Magnification NA.32 M7 & M8 aspherized for perfect quality over curved field. M8 = 22 mm M7 = 5 mm Illumination system M2 Source position Reticle plane Position de la source Folding and Mask module M1 M8 M3 M4 M6 Reticle M5 M8 Relay mirror Projection system Plan de la pupille réelle Pupil position M7 M7 Plan image (wafer) Wafer 3
BEL Optics Performance Sphère de référence F/1.5 Wavefront error error < 3.5 3.5 nm nm RMS RMS (simple (simple path) path) Miroir M7 Miroir M8 Table XYZ Z X Y Table nid d abeille sur pieds gonflés Sphère de transmission F/1.5 Interféromètre RTI 41 HSFR HSFR Roughness < 1.5 1.5 Å RMS RMS (AFM (AFM measurements) MSFR MSFR Roughness < 1.5 1.5 Å RMS RMS (Interferometric (Interferometric microscope measurements) 4
BEL Optics product line Complete Complete set set of of optics optics installed installed in in BEL BEL at at CEA CEA LETI LETI since since Q4/22. Q4/22. 2. SAGEM SAGEM provides provides support support to to the the CEA CEA LETI LETI for for BEL BEL operations operations Metrology Metrology capabilities capabilities reinforced reinforced for for individual individual mirrors mirrors / / global global performance performance measurement. measurement. New New test test benches benches to to be be installed installed in in C1 C1 integration integration room room for for optics optics alignment alignment and and evaluation. evaluation. EUV Schwarzschild optics is now a new SAGEM product line Individual Mirror Test bench BEL at CEA LETI lab Global Test Bench 5
EXTATIC Program Through the EXTATIC program, the aim of SAGEM is to develop alternative strategies for projection optics manufacturing. 3 development axis have been highlighted Active mirror (AM) study and design Polishing process development for aspheric optics Associated metrology technology improvements 22 23 24 Q1/Q2 Q3/Q4 Q1/Q2 Q3/Q4 Q1/Q2 Q3/Q4 AM Study AM Design AM Demonstrator Polishing process development Demonstrator realisation Metrology development 6
An Active Mirror could help within an EUV PO Box Analysis of a PO box design Reticle M2 M1 M3 M6 Wafer M5 ORA M O D U L A T I O N 1..9.8.7 M O.6 D.6 U L.5 A.5 T I O.4.4 N.3.2.1 ORA 1..9.8.7.3.2.1 PO PO Box Box MTF MTF DIFFRACTION MTF DIFFRACTION MTF 3-Jul-2 3-Jul-2 DIFFRACTION LIMIT 65 484 975 1331 17545 2178 2615 325 34485 R T 65 484 975 SPATIAL 1331 FREQUENCY 17545 (CYCLES/MM) 2178 2615 325 34485 SPATIAL FREQUENCY (CYCLES/MM) M4 T DIFFRACTION R.9 FIELD LIMIT ( -3.76 O ) T R.9 FIELD ( WAVELENGTH WEIGHT T -3.76 O ) R 1. FIELD ( -3.86 O ) WAVELENGTH 13.4 NM WEIGHT 1 T R 1. T FIELD ( -3.86 O ) 13.4 NM 1 R 1. FIELD ( -3.96 O ) T R 1. FIELD ( -3.96 O ) DEFOCUSING. DEFOCUSING. R T Pupil mirror : could be an active mirror?? Active Active mirror mirror function function :: Quasi-static Quasi-static static correction of of tilt, tilt, decenter, decenter,, radius radius and and some some Zernike Zernike surface surface deformations Active Active mirror mirror advantages :: Relax Relax mirror mirror manufacturing tolerances Keep Keep performances through through operational life life => => Reduces Reduces Cost Cost of of Ownership 7
An Active Mirror reduces effects of mirrors loss of position Perfect PO Box Example of simulated case : dx (µm) dy (µm) M1.8. M3 -.5.7 M4.3.8 M5. -.8 M6 -.9.3 Loss of performance Quality is well restored Active mirror command : Tilt 13 nm Focus 1.7 nm Astig 2.6 nm Coma 2.6 nm Sphere.13 nm 8
Efficiency of the Active Mirror Surface figuring correction.6.6.4.4.2.2 Coma on M3 mirror (Z8) Computation of the defects generated for different zones of the ring field.6.6.4.4.2.2 2 4 6 8 1 12 14 16 18 2 4 6 8 1 12 14 16 18 -.2 Zi -.2 -.4 -.4 -.6 -.6 Computation of the performance including active correction 2 4 6 8 1 12 14 16 18 -.2 2 4 6 8 1 12 14 16 18 -.2 -.4 -.4 -.6 -.6 Zi Computation of the AM correction for all the zones of the ring field 9
Efficiency of the Active Mirror Example of mirror deformation correction M1 M3 M4 M5 M6 Z5.5.5.5.5.5 Z6.5.5.5.5.5 Z7.25.25.6.25.25 Z8.12.12.5.12.12 Z9.5.5.1.5.5 Z1.25.25.6.25.25 Z11.12.12.3.12.12 Z12.5.5.5.5.1 Z13.5.5.1.5.5 Z14.6.6.6.6.6 Z15.5.5.5.5.5 Z16.25.25.25.25.25 Total (nm).95.98 1.35.95.82 Table of mirror surface errors 1
An Active Mirror reduces effects of mirrors loss of figure 1 nm deformation on 5 mirrors Max Mean : 4.11 nm RMS : 3.2 nm RMS With active mirror best correction The active mirror reduces image degradation by a factor 4 Max Mean : 2.3 nm RMS :.85 nm RMS 11
Efficiency of the Active Mirror is demonstrated Synthesis of the gains thanks to the active mirror on component manufacturing, P.O. box alignment and in-use stability requirements. Centring Tilt WFE Curvature radius Relaxation of manufacturing tolerances thanks to the active mirror x4 x4 x3 à x5 x4 Review active mirror technologies Selection of the technology Go ahead for EUV active mirror demonstrator manufacturing 12
Requirements Active Mirror demonstrator The main requirements of the demonstrator are : Correction of the first 1 Zernike polynomials (Z( i ) Correction accuracy <.3 nm RMS for the first 15 Z i Correction accuracy <.2 nm RMS for Z i > 15 Correction stability <.1 nm RMS Tilt stability <.1 µradµ Dimensions : diameter 2 mm and useful aperture 18 mm Progress Demonstrator design is in progress as well as elementary technological ogical validations. To reduce cost, actuator pattern optimisation computations have been carried out. Manufacturing phase is expected to start at the end of 23. 13
Polishing process development Mirrors for EUV PO box are off axis aspherics with stringent requirements. Aspherical sag 1 µm, slope 1 µm/mm HSFR and MSFR <.15 nm RMS These specification require development of polishing technologies s for reaching the surface error as well as the roughness values. BEL optics manufacturing have proved that the used polishing process cess allows to reach a.15 nm RMS roughness. We are working on polishing tools and more particularly on ion beam beam figuring improvement. New Ion beam facility Ion beam figuring 14
Polishing activities To demonstrate its ability to produce mirrors of a PO box optics,, we have started the manufacturing of a representative aspherical specimen. The characteristics of this mirror are : Maximum aspherisation 7 µm Slope.8 µm/mm Ellipsoid shape (for metrology facilities) sag difference in µm sag difference in µm 7 7 6 6 5 5 4 4 3 3 2 2 1 1 Sag 1 2 3 4 5 6 7 8-1 1 2 3 4 5 6 7 8-1 mm mm gradient in µm/mm gradient in µm/mm,9,9,8,8,7 Slope,7,6,6,5,5,4,4,3,3,2,2,1,1 -,1 1 2 3 4 5 6 7 8 -,1 1 2 3 4 5 6 7 8 mm mm Manufacturing of this mirror is in progress. First results expected before end of 23 15
Metrology activities Development of metrology test benches for measuring the aspherical demonstrator. Two complementary technologies will be mainly used : HeNe Interferometry with a specific test bench Shack Hartmann metrology Partnership with Imagine Optic for implementing a high accuracy S.H Use of patented rotated micro lens matrix cross talk reduction between pixels Classic microlenses Rotated microlenses 16
Conclusions Through the different EUV programs, SAGEM has realised a first set of optics for an EUV micro exposure tool (BEL) installed at CEA LETI since dec.. 2 provides support to CEA LETI for BEL setup and improvement has demonstrated the interest of active mirror module within an EUV PO box has engaged the development of an active mirror demonstrator is pursuing its efforts in polishing and metrology technologies for EUV optics (and photomask substrates) Thanks to CEA / LETI, MinEFi and MEDEA+ 17