Electron Projection Lithography (EPL) - · PDF file29.01.2004 · E-Beam Lithography Program ... Electron Projection Lithography (EPL) 200mm Wafer EPL Mask: Image placement, CD accuracy,

Electron Projection Lithography(EPL)

AgendaOverview of EPL development (22 min):

M. Yamabe (Selete)

Exposure tool (20 min): K. Suzuki (Nikon)

EPL mask (12 min): O. Nagarekawa (HOYA)

Data processing (10 min): M. Shoji (NCS)

Summary (6 min): M. Yamabe (Selete)

3Litho Forum, January 29, 2004, M. Yamabe, Selete

Overview of EPL development

Masaki YAMABEE-Beam Lithography Program

Research Department 2Semiconductor Leading Edge Technologies, Inc. (Selete)


Outline

EPL program overviewExposure tool and its applicationEPL resistsEPL masksEPL mask inspectionEPL mask repairData processing for EPL maskSummary


DeflectorStage Scan

Reticle Stage

Reticle

Beam Deflection

Sub-field 1x1mm

Sub-fields

Deflector

Beam Deflection Wafer Stage

Sub-field 0.25x0.25mm

Wafer

Stage Scan

Projection Lens x1/4 Mag.

Electron Projection Lithography (EPL)200mm Wafer

EPL Mask:Image placement, CD accuracy,Inspection, Repair, Cleaning,Data processing

Strut

2umt membrane(Stencil mask)

Mask pattern

8000 Sub-fields

Exposure tool:Resolution, Accuracy (CD, Stitching, Overlay), Throughput

Resist:Resolution, Sensitivity, Etching durability,Pattern quality, Pattern collapse

1mm250um

Wafer pattern

Mask patterns are1/4 demagnified and stitched

Figure:Courtesyof Nikon


EPL program schedule

Exposure tool

2001 2002 2003 2004 2005Calendar year 2006

First tool delivered to Selete Production tool

ResistsSamples (65nm → 45nm → 32nm →)

Products

Mask ProductsSamples

Mask inspectionProto type tool

Production toolProto type tool

Production tool

Mask repair

Data processingProducts

Selete program

(65nm → 45nm → 32nm →)


Who is developing EPL ?Exposure tool

NikonResists

FFA, JSR, TOK, Shipley etc.

Pattern collapse preventionTEL, DNS-KOBELCO

MasksHOYA, Toppan, DNP, Team Nanotec

Mask inspectionTOKYO SEIMITSU - HOLON

Mask repairSII NanoTechnology, NawoTec

Mask cleaningSumitomo Heavy Industry

Data processingSII, NCS, ISS, NIS,

Fujitsu, Hitachi ULSI, etc.

ConsortiaSelete, Intl. SEMATECH

UniversitiesU. of Wisconsin, U. of Virginia


EB stepper (NSR-EB1A) at Selete clean roomElectron

gun

Wafer stage& chamber

Mask stage& chamber


EPL application study for Via formation

Resist pattern Etched insulator

80nm

75nm

Exposed 300mm waferChip size: 20mm x 25mm, 115 chips

Resist pattern and etched insulatorResist: 400nmt, Etching depth: 300nmInsulator: Low-k material


EPL resist status

20

Resist for hole (Positive) Resists for line

Sens

itivit

y [10

0kV]

(uC/

cm2 )

Resolution [L/S] (nm)

0

10

5

15

0 8020 40 60 100 Sens

itivit

y [10

0kV]

(uC/

cm2 )

Resolution [L/S] (nm)

0

10

5

15

0 8020 40 60 100

20

Target

NegativePositive

Target


EPL positive tone resistsFEP-137（FUJIFILM ARCH）

8.8uC/cm2

82nm 70nm 56nm 42nm

TEBM1615（JSR）

8.0uC/cm2

82nm 70nm 56nm 42nm

82nm 70nm 56nm 42nm

EPLP-011EL（TOK）

6.7uC/cm2

Exposure tool: Nikon 100kV experimental column, Resist: 350nmt (FEP-137: 400nm) on Bare Si, Pattern: C/H (1:2)Courtesy of FUJIFILM ARCH, JSR, TOK, and Nikon


EPL masks

Stencil mask

(Thick) continuous membrane mask

PatternW(30nm)/Cr(5nm)scatterer

SiN membrane(100~150nm)

Si (2µm) Pattern opening

PatternDiamond-like carbon (DLC) (~600nm) scatterer

DLC membrane(~30nm)

*: H.Yamashita, I. Amemiya, et al., J. Vac. Sci. Technol. B 18, 3237 (2000). Ultra thin membrane (UTM) mask*


EPL stencil masks

Toppan DNPHOYAPattern: Selete benchmark pattern data “Anaheim” (70nm SoC) Courtesy of HOYA, Toppan, and DNP


EPL Ultra Thin Membrane (UTM) masks

Mask

EPL image

Diamond-like carbon (DLC) UTM mask(Courtesy of HOYA)

Carbon / SiNx / Carbon stacked UTM mask(Courtesy of International SEMATECH & Team Nanotec)

(SEM Photo Courtesy of Nikon)


EPL stencil mask inspection toolStepping

Cont

inuo

us st

age m

ovem

ent

Beam Strip

Stagedrive

Stage

Electron gunIlluminationelectron optics

Mask

Projectionelectron optics TDI CCD

sensor

Signalprocessing

unitControl unit /

image processingunitMagnified

transmissione-beam image

Mask


EPL stencil mask inspection tool

Photo: Courtesy of Tokyo Seimitsu and HOLON


Stencil mask defect inspection results (hole)

101nm

20nm

98nm

27nm

145nm

122nm

81nm

37nm

145nm

88nm

51nm

30nm

145nm

112nm

95nm

54nm

30nm

139nm

96nm

81nm

43nm

24nm

156nm

105nm

68nm

54nm

203nm

118nm

78nm

54nm

159nm

129nm

95nm

71nm

54nm

152nm

112nm

88nm

44nm

142nm

100nm

68nm

52nm

Hole Edg Int Edg Ext Cor Ext Cor Int Ove Size Und Size Elong Trunc Misp

2 pixel

1 pixel (50nm)100% in 20 runs60~80% in 20 runs0~40% in 20 runs

Defect sizes aremeasuredby transmissionSEM at DNP

Main pattern: 240nm on mask


Repair of stencil mask

Opaque defect repair Clear defect repairFIB or e-beam

Etching gas(optional)

Scan

Precursor gas

Scan

FIB or e-beam

Etching or gas assist etching Beam induced deposition


Stencil mask defect repair FIB toolIon optics Ion optics

Courtesy of SII

Mask loader Main chamber


FIB stencil mask repair

Pattern: 800nm Pitch on Mask

Beforerepair

Opening

Si

Afterrepair

Cleardefect

Opaquedefect

Miss-sizedefect

1.8um35nm

Defect

Repaired

DefectRepair of defects in EPL stencil mask

SIM image Trans.SEM

image

Exposureresults

Maskpatterns

w/odefects

Maskpatterns

withdefects

Maskpatterns

afterrepair

Courtesy of Seiko Instruments

Exposure results ofrepaired and un-repaired pattern

Fine FIB gas assist etching of EPL stencil mask


NFS shared storage

Hierarchical CM split

Hierarchical PEC

Re-hierarchicalizing

Flattening+contouring

Mask layout

Hierarchical SF splitWrite results

Endsignals

Sub-processes

Cluster nodes Linux PC

Look upWrite result

Sub-field data

SF: Sub-fieldCM: ComplementaryPEC: Proximity effect correction

&

&

Cell A

Cell B

Configuration of data processing system(Selete’s PC clustered hierarchical system)

Design data (GDSII)

Mask data (GDSII)


Improvement of complementary split softwareProcessing time Data volumeTime Ratio Volume Ratio

Hierarchical processing 7 m 43 s 1.66 GB

Conventional 18 h 20 GBStress check function 9 h 12.5 GBPC cluster (10 PCs) 54 m 12.5 GB

Overall 7 m 43 s 0.00714 1.66 GB 0.083

0.50.1

0.143

0.6251

0.133

Conven-tional

Stresscheck

PCcluster

Rehierar-chical

Overall

Proc

essin

g tim

e [hr

]Da

ta vo

lum

e [GB

]

5

10

25Processing timeData volume20

15

0 Chip: 70 nm SoCMask: 200mmSoftware M-Split


Exposure results using complementary masks

Stitching accuracy: 20 nm

Exposure resultsComplementarilysplit databy M-Split

Exposure tool:EB stepper NSR-EB1A

Mask patterns


Exposure results using complementary masks


SummaryTechnology development:

Considerable numbers of developments are ongoing.They will be ready before the release of production exposure tool.

Exposure tool:The first tool was delivered and application study has started.

Resists:Commercially available.

Masks:Samples of stencil mask are available from mask suppliers.

Mask inspection and repair:E-beam inspection tool and FIB repair tool are under development.

Data processing software for mask:Commercially available.

Documents

Electron Projection Lithography (EPL) - · PDF file29.01.2004 · E-Beam Lithography Program ... Electron Projection Lithography (EPL) 200mm Wafer EPL Mask: Image placement, CD accuracy,