SPIE Photomask BACUS 2008 lbl.gov SEMATECH Berkeley Actinic Inspection Tool 1 Advanced Materials Research Center, AMRC, International SEMATECH Manufacturing Initiative, and ISMI are servicemarks of SEMATECH, Inc. SEMATECH, the SEMATECH logo, Advanced Technology Development Facility, ATDF, and the ATDF logo are registered servicemarks of SEMATECH, Inc. All other servicemarks and trademarks are the property of their respective owners. Benchmarking EUV Mask Inspection Beyond 0.25 NA The SEMATECH Berkeley Actinic Inspection Tool A I T An EUV-wavelength mask inspection microscope

SPIE Photomask BACUS 2008 lbl.gov SEMATECH Berkeley Actinic Inspection Tool 2 "1%" depth bi-layers 13.4 nm215 nm nm53.6 nm nm20.6 nm 3 EUV light penetrates deeply into the resonant ML structure. 488-nm and 266-nm light barely reaches below the surface. Field Penetration for three s depth [nm] Field intensity vs. depth At-wavelength testing probes the actual multilayer response. Different wavelengths see the same ML structure differently

SPIE Photomask BACUS 2008 lbl.gov SEMATECH Berkeley Actinic Inspection Tool 3 UpgradesResolution (Uniformity) AberrationsModeling, Measurement, Reduction LinewidthMeasurement, Repeatability LBNL:Kenneth A. Goldberg, Iacopo Mochi, Patrick Naulleau AMD :Bruno LaFontaine Samsung:Hakseung Han SEMATECH:Sungmin Huh Advanced Materials Research Center, AMRC, International SEMATECH Manufacturing Initiative, and ISMI are servicemarks of SEMATECH, Inc. SEMATECH, the SEMATECH logo, Advanced Technology Development Facility, ATDF, and the ATDF logo are registered servicemarks of SEMATECH, Inc. All other servicemarks and trademarks are the property of their respective owners. Benchmarking EUV Mask Inspection Beyond 0.25 NA

SPIE Photomask BACUS 2008 lbl.gov SEMATECH Berkeley Actinic Inspection Tool 4 AIT: An EUV Zoneplate Microscope  = 13.4 ± 0.01 nm, tunable {0.25, 0.30, 0.35} NA (4x) 907x–1000x mag 25–35 sec/exposure 250 images / 8h Si 3 N 4 5 lenses—different mag and NA CCD

SPIE Photomask BACUS 2008 lbl.gov SEMATECH Berkeley Actinic Inspection Tool NA0.25 NA0.35 NA (4x) 100 nm (mask) lines 25 nm (wafer) New CCD + higher mag = higher contrast. Higher-NA lens  Improved resolution. EIPBN 2008

SPIE Photomask BACUS 2008 lbl.gov SEMATECH Berkeley Actinic Inspection Tool 6 Contrast Transfer Function (CTF) We now achieve much higher contrast below 225 nm hp 150 nm lines 2008  NA Mask [nm] 4x [nm] 0

SPIE Photomask BACUS 2008 lbl.gov SEMATECH Berkeley Actinic Inspection Tool 7 Improving performance through alignment The off-axis zoneplates have a small field of view, 5–8 µm, so alignment is critical. alignment (aberration minimization) imaging performance detailed feedback through-focus image analysis Accurate measurement of contrast, defects, line-width, etc. all rely on low aberrations.

SPIE Photomask BACUS 2008 lbl.gov SEMATECH Berkeley Actinic Inspection Tool nm Contacts 32-µm-wide area 5 µm

SPIE Photomask BACUS 2008 lbl.gov SEMATECH Berkeley Actinic Inspection Tool nm Contacts 16-µm-wide area 2 µm

SPIE Photomask BACUS 2008 lbl.gov SEMATECH Berkeley Actinic Inspection Tool nm Contacts 8-µm-wide area 1 µm

SPIE Photomask BACUS 2008 lbl.gov SEMATECH Berkeley Actinic Inspection Tool 11 Through-focus, contacts reveal aberrations clearly 0.8 µm 1.26 µm z steps 0.80 µm z steps focus 0.8 µm August April ’08

SPIE Photomask BACUS 2008 lbl.gov SEMATECH Berkeley Actinic Inspection Tool 12 Through-focus, contacts reveal aberrations clearly August April ’ µm Astigmatism Astigmatic Displacement (AD) ≥ 2.0 µm (125 nm wafer) RMS Wavefront Error ≥ 0.23 Waves RMS Astigmatism Astigmatic Displacement (AD) ≥ 0.3 µm (19 nm wafer) RMS Wavefront Error ≥ 0.08 Waves RMS

SPIE Photomask BACUS 2008 lbl.gov SEMATECH Berkeley Actinic Inspection Tool 13 Models help assess our position within the field Zoneplate field of view Field-dependent Astigmatism Model Measured Astigmatism 22 µm one image Waves RMS Please see I. Mochi, et al. EUVL Symposium µm

SPIE Photomask BACUS 2008 lbl.gov SEMATECH Berkeley Actinic Inspection Tool 14 Testing line-width measurement capabilities 1:1 lines  intensity-threshold reference. 10 regions per image through-focus. LW based on best-focus images. through-focus 10x per location. 10 regions per image. best focus = highest contrast. Assume 1:1 lines, calculate a global “best threshold” value.  Statistics. Mask: MET-3 M AMD/IFX/AMTC Mask: PDM-AIT[1] Samsung/SEMATECH 1. Measuring biased lines 2. Repeatability testing with 1:1 lines

SPIE Photomask BACUS 2008 lbl.gov SEMATECH Berkeley Actinic Inspection Tool 15 Measuring Biased Lines Mask: MET-3 M , AMD/IFX/AMTC 500 nm

SPIE Photomask BACUS 2008 lbl.gov SEMATECH Berkeley Actinic Inspection Tool 16 Mask CD 350 Measuring CD from biased lines — 1000 nm pitch 1 µm nm reference 16.1 nm (mask) 4.0 nm (wafer) 33

SPIE Photomask BACUS 2008 lbl.gov SEMATECH Berkeley Actinic Inspection Tool 17 Programmed-defect arrays—aerial images 176 nm mask 44 nm 4x, ADT 35 nm 5x, MET 176 nm 1 µm

SPIE Photomask BACUS 2008 lbl.gov SEMATECH Berkeley Actinic Inspection Tool nm mask 33 nm 4x, ADT 26 nm 5x, MET Programmed-defect arrays—aerial images 1 µm 132 nm

SPIE Photomask BACUS 2008 lbl.gov SEMATECH Berkeley Actinic Inspection Tool nm mask 28 nm 4x, ADT 22 nm 5x, MET Programmed-defect arrays—aerial images 1 µm 110 nm

SPIE Photomask BACUS 2008 lbl.gov SEMATECH Berkeley Actinic Inspection Tool nm mask 22 nm 4x, ADT 18 nm 5x, MET Programmed-defect arrays—aerial images 1 µm 88 nm

SPIE Photomask BACUS 2008 lbl.gov SEMATECH Berkeley Actinic Inspection Tool ± 1% Measurement Repeatability Testing—176 nm lines 1 µm 176 nm mask 44 nm 4x, ADT 35 nm 5x, MET 6.8 nm (mask) 1.7 nm (wafer) 33 Test #

SPIE Photomask BACUS 2008 lbl.gov SEMATECH Berkeley Actinic Inspection Tool 22 Measurement Repeatability Testing—132 nm lines 132 nm mask 33 nm 4x, ADT 26 nm 5x, MET 1 µm 88 ± 1% 6.0 nm (mask) 1.5 nm (wafer) 33 Test #

SPIE Photomask BACUS 2008 lbl.gov SEMATECH Berkeley Actinic Inspection Tool 23 Measurement Repeatability Testing—110 nm lines 1 µm 110 nm mask 28 nm 4x, ADT 22 nm 5x, MET 74 ± 4% 3.7 nm (mask) 0.9 nm (wafer) 33 Test #

SPIE Photomask BACUS 2008 lbl.gov SEMATECH Berkeley Actinic Inspection Tool ± 6% Measurement Repeatability Testing—88 nm lines 8.0 nm (mask) 2.0 nm (wafer) 1 µm 88 nm mask 22 nm 4x, ADT 18 nm 5x, MET 33 Test #

SPIE Photomask BACUS 2008 lbl.gov SEMATECH Berkeley Actinic Inspection Tool 25 Measurement Repeatability Testing Summary Mask CD ideal Contrast Transfer Function CD Measurement 3  Wafer (4x)

SPIE Photomask BACUS 2008 lbl.gov SEMATECH Berkeley Actinic Inspection Tool 26 Through-focus analysis of 180 nm CD (mask) lines Defocus Z [µm] best LW Uncertainty 3  nm

SPIE Photomask BACUS 2008 lbl.gov SEMATECH Berkeley Actinic Inspection Tool 27 Linewidth: Main Issues and solutions Signal-to-noise ratio Measurement dependence on exposure time Illumination uniformity X-Scanning illuminator; soon XY scanning System stability Mask lateral shift during z motion affects illumination and aberrations Improved Z actuator, -scan method Zoneplate and illumination alignment How stable and repeatable can we make it? What sorts of feedback are available to correct it? Characterizing aberrations, refining alignment

SPIE Photomask BACUS 2008 lbl.gov SEMATECH Berkeley Actinic Inspection Tool 28 Conclusion System upgrades: improved resolution, contrast, 0.35 NA (4x) Aberrations: reduced by alignment & analysis Astigmatism is down, from 0.23 to 0.08 RMS Contrast: 71% for 88-nm lines (22 nm 4x) Linewidth 3  : Repeatability ~5 nm 3  (1.25 nm on wafer) More improvements will come from a combination of hardware & software solutions. System upgrades: improved resolution, contrast, 0.35 NA (4x) Aberrations: reduced by alignment & analysis Astigmatism is down, from 0.23 to 0.08 RMS Contrast: 71% for 88-nm lines (22 nm 4x) Linewidth 3  : Repeatability ~5 nm 3  (1.25 nm on wafer) More improvements will come from a combination of hardware & software solutions.

SPIE Photomask BACUS 2008 lbl.gov SEMATECH Berkeley Actinic Inspection Tool 29 1 µm Special Thanks! CXRO David Attwood Seno Rekawa Drew Kemp Nathan Smith Paul Denham Erik Anderson Bob Gunion Eric Gullikson Ron Tackaberry For More Information: