Post on 13-Feb-2017
transcript
EUV Mask Workshop 2004 1
Challenges of EUV masks and preliminary evaluation
Naoya HayashiElectronic Device LaboratoryDai Nippon Printing Co.,Ltd.
EUV Mask Workshop 2004 2
Contents• Recent Lithography Options on Roadmap • Challenges for EUV Mask
– Multi Layer Substrates– Defect Free Mask
• Absorber Delineation (Writing Tools & Processes)• Inspection & Repair• Metrology
– With Preliminary Results
• Summary
EUV Mask Workshop 2004 3
Technology Node
2007 2013 20192004 20162010
hp90 hp65 hp32 hp16hp22hp45
2003 2005 2006 2008 2009 2011 2012 2014 2015 2017 2018
Research Required Development Underway Qualification/Pre-Production Continuous Improvement
This legend indicates the time during which research, development, and qualification/pre-production should be taking place for the solution.
DRAM Half-pitch(dense lines)
Tech
nolo
gy O
ptio
ns a
t Tec
hnol
ogy
Nod
es(D
RA
M H
alf-P
itch,
nm
)90 193 nm
65 Narrowoptions
193nm + LFD193nm immersionPEL
32EUV193nm immersion + LFD157nm immersion + LFD, ML2Imprint
Narrowoptions
22 Narrowoptions
EUVInnovative 157nm or 193 nm immersionML2Imprint, innovative technology
16 Narrowoptions
Innovative technologyML2, EUV + RET, imprint
45193nm immersion + LFDEUVML2, 157nm immersion, PEL
Narrowoptions
Potential Lithography Solutions
EUV Mask Workshop 2004 4
65nm-45nm node lithography/mask options 193nm extension (RET from mask side)
• Aggressive OPC (ie Scattering Bar of 100nm width) will be inevitable.• High transmission att-PSM (both embedded shifter type and CLM) with “tritone” feature is thought as a possible option.• Aggressive Alt-PSM adoption..
193nm immersion lithography• There is no major mask related issue for immersion lithography.• RET will be accelerated.• 157nm Dry and/or Immersion will be the backup for 45nm and beyond.
Electron beam lithography• LEEPL technology has been focusing on hole pattern for memory devices.• Image placement measurement, defect Inspection/repair, are still in development stage.
EUV lithography• Research & Development for production engineering is required.• Especially, defect-free multi layer substrate, inspection/repair, are critical issues.
EUV Mask Workshop 2004 5
Current Status and Schedule for EUV Mask Development
• Current Status– Through research activity with consortia, trying to
define EUV mask specifications• Absorber, buffer/capping layer materials• Patterning processes• Printable defects, inspection, metrology, etc.
– Starting to provide evaluation plate 2004/H2.– Multilayer substrate will be available from several
vendors.• Future Plan
– Investment for production will start 2006
EUV Mask Workshop 2004 6
EUVL mask stacking structure
Absorber layer(s)
Buffer layer
Capping layer
Multilayer (about 40 pairs of Mo and Si)
Underlayer
LTEM
Conductive coating
EUV Mask Workshop 2004 7
EUVL blank initial test results•Tantalum based absorber on Chromium based buffer•Etching capability test of 200nm patterns
•Repair capability test with Micromachining
Hole Iso-Space
Iso-Line L&S
Defect size 160nm
Ref
eren
ceA
fter r
epai
r
•Currently, several sets of materials from various blank suppliers are tested to investigate their capability as absorber and buffer.
EUV Mask Workshop 2004 8
Cross section profile of TaGeN
Dense hole Isolate lineDense line
CF4 gas process
Cl2 gas process
Pattern size 200nm
•Vertical side wall were obtained in both gas process
courtesy by ASET
EUV Mask Workshop 2004 9
Etch bias uniformityExposure tool : 50kV EB Measurement tool : CD-SEMArea size : 122 X 122 mm2 Pattern : 400 nm Iso-Space
+5nm -5nmCF4 process Cl2 process
Mean : -27.3nmMax : -21.62nmMin : -33.71nm3sigma : 8.36nm
Mean : 2.05nmMax : 9.31nmMin : -4.31nm
3sigma : 9.95nm
EUV Mask Workshop 2004 10
EUV mask reflectivity
0
10
20
30
40
50
60
70
12.5 13 13.5 14 14.5Wavelength [nm]
Ref
lect
ivity
[%]
•Centroid wavelength : 13.54nm•Peak reflectivity : 63.8%
EUV reflectivity after buffer layer dry etchingAbsorber layer : CF4 gas process
Buffer layer : Cl2 + O2 gas process
courtesy by ASET
EUV Mask Workshop 2004 11
EUV mask pattern and wafer print result70nm line and space pattern
Mask pattern Wafer pattern( Exposure tool : HiNA set 3)
5um 1um
courtesy by ASET and Nikon
EUV Mask Workshop 2004 12
Availability of mask infrastructures
EUV Mask Workshop 2004 13
Mask Writing SystemsVendor Systems
Etec Systems MEBES-RSB
Etec Systems ALTA-4000
JEOL JBX-3030
Hitachi HT HL-7000M
Nu Flare EBM-4000
Writing Strategy
Variable Shaped E-Beam
Raster Scan
Spot Multi-Laser-Beam
Raster Scan
Variable Shaped E-Beam
Vector Scan
Variable Shaped E-Beam
Vector Scan
Variable Shaped E-Beam
Vector Scan Accelerating Voltage
50KeV (257nm) 50KeV 50KeV 50KeV
Max.Substrate Size
6 inch sq. 6 inch sq. 7 inch sq. 7 inch sq. 230mm sq.
Writing Area - 144 x 144 mm - 7 inch x 7 inch 222 x 228.6 mm
Min.Feature Size
0.20 um 0.35 um - 0.10 um 0.25 um
Min.Addressing 1.0 nm 2.5 nm 1.0 nm 1.0 nm 1.0 nm
Pattern Position Accuracy
12 nm(3σ) 22 nm(3σ) 15 nm(Max.) 15 nm(3σ) 12 nm(3σ)
Overlay Accuracy
8 nm(3σ) 15 nm(3σ) - - 10 nm(3σ)
Butting Error 10 nm(Mean+R/2) 10 nm (Mean+R/2) 15 nm(Max.) 10 nm(Mean+3σ) -
CD Accuracy (Global Unif.)
7 nm ( 3σ) 12 nm (Range/2) 8 nm(3σ) 8 nm(3σ) 7 nm(3σ)
Remarks 2 Pass Writing 4 Pass Writing 2 Pass Writing 2 Pass Writing 4 Pass Writing
EUV Mask Workshop 2004 14
Resist material vs. Resolution•Resist SEM Image (minimum resolution)
CAR_A100nm
40nm
70nm
90nm
Isolated space
40nm
55nm
65nm
CAR_B100nm
80nm 35nm
75nm
65nm
Non-CAR_A300nm
Dense space 100nm
Hole
120nm
ResistThickness
CAR_A400nm
EUV Mask Workshop 2004 15
Mask Inspection Systems
Syetem MD3000 LM7000 LM7000B SLF87KLA575(576)
DUV Aera193
Maker Lasertec NEC NEC KLA-Tencor KLA-Tencor AMAT
Mode D/D (Cell shift) D/B, D/D D/B, D/D D/B, D/D, SL D/B, D/D D/D, (D/M)(Aerial Image)
Illumination forinspection
Trans only Trans only Trans andReflect
Trans andReflect
Trans, Reflect Trans only
Wavelength[nm]
248 266 266 365 257 193
Pixel size [nm] 125 100 100 150 125 (90) 150
Sensitivity [nm] 100 (80) 100 80 100 80 (70) 10%CD@wafer
Min. Line width[nm]
300 400 280 400 B225/W255(B180/W200)
Not specified
Scan Time [min]100mm sq.
120 122 195 74 90 (175) 120
EUV Mask Workshop 2004 16
Absorber layer defect repair
Evaluated repair technique• FIB-GAE (Gas Assist Etching)• AFM Machining
XeF2 gas
Ga+ beam
TaGeN
SubstrateCr
FIB-GAE AFM Machining
TaGeN
SubstrateCr
AFM tip (Diamond)
EUV Mask Workshop 2004 17
SEM images of AFM machining defect repair results
ReferenceBefore buffer layer dry etching
•1um line and space•Defect pattern size 0.5 um
TEST 1-3X bias 0nmZ bias 5nm
TEST 1-1X bias 40nmZ bias 5nm
TEST 2-2X bias 20nmZ bias 0nm
TEST 1-2X bias 20nmZ bias 5nm
EUV Mask Workshop 2004 18
Mask Topography Measurement with CD-AFM
Differences Between 1D and 2D SFM Scan
direction
Servo direction
Scan direction
Servo direction
EUV Mask Workshop 2004 19
Summary• Mask technology development for EUV has been
establishing with Consortia at feasibility study stage.• Most of current infrastructures and technologies have been
adapting for preliminary evaluation of EUV mask making.• Ta based absorber material has been patterned successfully.• Various repair technologies for absorber pattern has been
evaluating.• Issues are
– Quality of substrate material (Specifications??)– Improvement of mask quality (CD, etc.)– Inspection & repair– Cleaning and mask handling
• What do you really want?!• Need feed back from exposure result to define “realistic”
specifications.– Printable defects, flatness, surface treatment, etc.