Progress in full field EUV lithography program at IMEC

Transcription

1 Progress in full field EUV lithography program at IMEC A.M. Goethals*, G.F. Lorusso*, R. Jonckheere*, B. Baudemprez*, J. Hermans*, F. Iwamoto 1, B.S. Kim 2, I.S. Kim 2, A. Myers 3, A. Niroomand 4, N. Stepanenko 5, F. Van Roey*, I. Pollentier* and K. Ronse* *IMEC, Leuven, Belgium 1 On assignment from Matsushita 2 On assignment from Samsung 3 On assignment from Intel 4 On assignment from Micron 5 On assignment from Qimonda International EUVL Symposium, October 2007, Sapporo

2 EUVL program contents vs EUV critical issues 3 projects EUV masks Handling Defect free in fab ADT assessment EUV Source Power, lifetime Reflective optics Quality and lifetime EUV EUV resist resists process Sensitivity, LER, resolution 2

3 EUVL program contents EUV resists EUV Masks ADT assessment EUV Source Power, lifetime Reflective optics Quality and lifetime Resist Resist process Sensitivity, LER, resolution 3

4 EUV resist project Key objectives EUV resists Benchmark EUV resist performance versus requirements Drive EUV resist suppliers Demonstrate EUVL ability for small electrically working circuits Build fundamental understanding for EUV resist out-gassing requirements for EUVL high volume manufacturing 50nm 40nm 30nm 25nm Resist Screening at PSI RGA Energetiq source in close collaboration with all major resist suppliers worldwide Optics chamber Process Wfr/reticle chamber loadlock EUV Technology Outgassing Tool 4

5 Reference resist (Interference litho) MET-2D, 80nm resist thickness 50 nm (80nm thick) nm 30nm 45 nm 25nm 40 nm nm 32.5 nm +-97 nm Energy size Exp. Lat. (50nm) LER (3σ) (50nm) Resolution 21.4 mj/cm 2 13% 5.1nm 80 nm 32.5 nm 5

6 Line Edge Roughness versus sensitivity LER results on 50nm lines (Interference lithography) nm resolved 3 sigma LER [nm] MET-2D ITRS Target dose [mj/cm2] Poster RE-P10 EUV resist process development for full field imaging, A. Niroomand et al 6

7 Line Edge Roughness versus sensitivity LER results on 50nm lines (Interference lithography) EUV-77 EUV-55 25nm resolved 3 sigma LER [nm] EUV-72 EUV-38 MET-2D EUV-73 ITRS Target dose [mj/cm2] Best overall performing resist is EUV-72 (high sensitivity with ~25nm resolution). Poster RE-P10 EUV resist process development for full field imaging, A. Niroomand et al 7

8 State of the art resist Q EUV-38 resist 50 nm nm 30nm 45 nm 25nm 40 nm nm 32.5 nm +-97 nm Energy size Exp. Lat. (50nm) LER (3σ) (50nm) Resolution 14.8 mj/cm 2 26% 5.2nm 25nm 50 nm 8

9 Overall best resist Q EUV-72 resist 50 nm nm 30nm 45 nm 25nm 40 nm nm 32.5 nm +-97 nm Energy size Exp. Lat. (50nm) LER (3σ) (50nm) Resolution 9.6 mj/cm 2 27% 5.9nm 50 nm ~25 nm 9

10 EUVL program contents EUV reticles Project EUV EUV Masks Masks Handling in fab ADT assessment EUV Source Power, lifetime Reflective optics Quality and lifetime Resist Sensitivity, LER, resolution 10

11 EUV reticle project Key objectives 2. EUV masks Benchmark EUV reticle performance versus requirements and blank architecture Build understanding on handling requirements for EUV mask lifetime in fab environment Build understanding on EUV mask defect specs requirements for defect free lithography Reflectivity (%) 0.8 Si Mo Ru Si Ru 0.5 Mo Cap thickness Blank reflectivity simulation in close collaboration with all major EUV mask (and blank) suppliers worldwide (including captive mask shops core partners) TNO Particle Scanner 11

12 Particle defect: variation of n&k 40nm L/S Cubic defect Space Width [nm] Space Width [nm] Defect Size [nm] Defect Size [nm] Material (n,k) C (1,0.001) (1,0.08) (0.85,0.001) (0.85,0.08) TaN SiO2 Cr Mo Si Ru C The particle material determines its printability. oral DI-01 Mask defect printability in full field EUV lithography, R. Jonckheere 12

13 Printability study of 4 types of mask defects by simulation Particle eg Carbon or opaque materials defect Critical particle size is ~14nm for C Printability depends on (n,k) Absorber defect Opaque & clear type Critical opaque defect size: is ~8nm Critical distance is typically 2-3X smaller than in ArF Local R%-loss Local carbon deposition If conformal it prints very quickly (from 2nm thickness onwards) ML defect Major effect from multilayer distortion near top (phase defects ~2-3nm). Material dependence only when the defect is located near the surface. Oral DI-01 Mask defect printability in full field EUV lithography, R. Jonckheere 13

14 EUV reticle long term reflectivity (degradation) Blank Reflectivity Si cap thickness 4nm Si keeps R±0.5% up to ~3nm C C deposition Si cap Mo Si 8nm Si: 3nm C gives 6% reflectivity loss Carbon thickness (nm) Protective mask capping layer (Si or Ru) and thickness can be optimized to minimize/maximize the sensitivity carbon deposition. Poster MC-P03 Study of capping layer impact on reflectivity loss by carbon deposition, Rik Jonckheere et al 14

15 EUVL program contents EUV ADT assessment project EUV Masks ADT assessment ADT assessment EUV Source Power, lifetime Reflective optics Quality and lifetime Resist Sensitivity, LER, resolution 15

16 EUV ADT assessment project Key objectives EUV alpha tool assessment Detailed characterization of EUV ADT fingerprint in terms of Imaging Overlay (single machine and matched machine) Detailed stability monitoring of EUV ADT In terms of optics contamination (image degradation) In terms of reliability and up-time (CoO) Develop and demonstrate correction techniques to compensate for EUV shadowing and flare Shadowing Compensation Flare map in close collaboration with ASML Flare map 16

17 ASML EUV Alpha Demo Tool (ADT) at IMEC First Light Apr 2007 Arrival Aug 2006 installed by Dec 2006 First Wafer May

18 ASML EUV Alpha Demo Tool First imaging with Sn source 50nm 1:1 40nm 1:1 35nm 1:1 CD=47.3nm CD=34nm Resist: Rohm Haas MET-2D Thickness 100nm NA=0.25, σ=0.5 Lens aberration reduction not finalized yet 18

19 ADT imaging 50nm V and H lines through dose mj 17.3 mj mj 17.8mJ 18.05mJ 18.3mJ 18.55mJ Vertical lines 57.3nm 59.6nm 52.6nm 52.7nm 51.2nm Horizontal lines 45.6nm 46.1nm 61.9nm 58.3nm 55.8nm 56.4nm 53.8nm 51.6nm 52.4nm Resist: Rohm Haas MET-2D Thickness 100nm NA=0.25, σ=0.5 Lens aberration reduction not finalized yet 19

20 ADT imaging 50nm V and H lines through focus Vertical L/S Horizontal L/S >160nm DOF Resist: Rohm Haas MET-2D Thickness 100nm NA=0.25, σ=0.5 Lens aberration reduction not finalized yet >240nm DOF 20

21 ADT imaging 40nm V and H lines through dose mj 17.8mJ 18.05mJ 18.3mJ 18.55mJ Vertical lines 42.8nm 40.9nm 38.2nm 33.6nm 34.2nm Horizontal lines 44.5nm 44.4nm 41.3nm 40.6nm 40.5nm Resist: Rohm Haas MET-2D Thickness 100nm Resist: Rohm Haas MET-2D NA=0.25, σ=0.5 Thickness 100nm Lens aberration reduction not finalized yet 21

22 ADT imaging 35nm V and H lines through dose 18.05mJ/cm mJ/cm mJ/cm 2 Vertical lines 39.1nm 37.nm 37.8nm Horizontal lines 44.3nm 43.8nm 43.5nm Resist: Rohm Haas MET-2D Thickness 100nm NA=0.25, σ=0.5 Lens aberration reduction not finalized yet 22

23 Shadowing on ASML EUV ADT with Sn Source Experimental validation 10 H-V experiment experiment 10 H-V simulation simulation Bias (nm) 0 Bias (nm) Slit Position (mm) Slit Position (mm) Measurement of 50nm 1:1 L/S at 0 0, 90 0, 45 0, Comparison of simulation and experiment for HV bias and bias through slit The experimental measurement of shadowing is in agreement with simulation prediction. Poster MA-P08 Shadowing effect compensation, G.F. Lorusso et al 23

24 Flare mitigation strategy Quantifying the quality of rule-based flare correction 40 Linear dependence of CD on flare 42 CD variation across die CD (nm) CD CD corrected = CDt arget + * Flare Flare local CD (nm) Flare (%) Site (#) CD Uncorrected CD Flare-corrected - not fractured CD Flare-corrected Fractured CD Flare-corrected Fractured Iterated on Flare Rule based correction re-sizes the CD at mask level to remove flare artifacts and seems very effective High-quality Full-Chip Flare map critical to implement rule-based Simulation SOLID-EUV 24

25 Full Chip Flare Map Density map with dummification Flare map 68 hrs High resolution full chip flare map can be calculated in reasonable time with standard EDA SW. oral OP-03 Flare mitigation strategies for EUV, A. Myers 25

26 Summary and outlook 1 st high resolution images demonstrated with ASML ADT equipped with a Sn source EUV resists are making steady progress Resolution of 25nm HP demonstrated with interference litho for several materials and sensitivities are reaching the 10mJ/cm 2 target LER is remaining the major challenge EUV reticles Extensive simulation study of defect printability and mask reflectivity Experimental phase in preparation with wide mask shop involvement Feasible Flare and Shadowing compensation strategies have been developed based on simulation. EUV IMEC is getting ready for experimental verification Full field EUV Lithography is becoming reality 26

27 Acknowledgements Many thanks to: ASML Noreen Harned, Hans Meiling, John Zimmerman, Bas Hultermans ASML EUV team at IMEC Age Bakker, Leon Romijn, Charles Schaap, Andre Van Dijk Sjoerd Lok, Joop Van Dijck Sigma-C (Synopsys) Brian Ward IMEC Tom Vandeweyer, Geert Vandenberghe PSI Harun Solak, Anja Weber Resist and BARC suppliers Mask shops IMEC IIAP partners 27

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