Overview of EUV Reticle Protection Technology:...

Semiconductor Leading Edge Technologies, Inc.

Overview of EUV Reticle Overview of EUV Reticle Protection Technology: Protection Technology:

Progress and Current StatusProgress and Current Status

Kazuya OtaKazuya Ota, Mitsuaki Amemiya, , Mitsuaki Amemiya, Takao Taguchi and Osamu SugaTakao Taguchi and Osamu Suga

MIRAIMIRAI--SeleteSelete6/12/2008 @Maui, Hawaii, USA6/12/2008 @Maui, Hawaii, USA

2008 International Workshop on EUV Lithography

20080612 2008 International Workshop on EUV Lithography 2

ContentsContents

• Introduction– Pellicle-less Reticle Handling– Potential Particulate Contamination Events– EUV Pods and Pellicle Alternatives

• Experimental Results– Reticle Shipping and Storage– In-Tool Handling– Electrostatic Chuck

• Remaining Issues and Future Works– SEMI Standardization– Evaluation of Particle Migration from Back to Front– Other Issues


MaskMask

PelliclePellicle

Traditional pellicle is not transparent for the EUV light (13.5nTraditional pellicle is not transparent for the EUV light (13.5nm)m)

No substantial pellicle for EUVNo substantial pellicle for EUV• EUV light is strongly absorbed by every material. • EUV light goes through the pellicle twice because

an EUV reticle is a reflective type.


ReticleReticle

Influence of Front Side ParticlesInfluence of Front Side Particles

WaferWafer

A particle (> ~30nm) on the front side of the reticle affects CD on the wafer.


Influence of Back Side ParticlesInfluence of Back Side Particles

OPD (OutOPD (Out--ofof--Plane Distortion)Plane Distortion)

ChuckChuck

Mask

ChuckChuck

IPD (In Plane Distortion)IPD (In Plane Distortion)

Oblique Illumination

Reticle Surface

Δz OPD = θ • Δz

θ

MaskMask

t: Thickness of Reticle

φ: Local Slope

IPD = t • φ

Deformation

A dot shows pattern position.


Potential Particulate Contaminating Events Potential Particulate Contaminating Events

EUV Scanner

Inspection Tool

*By courtesy of Nikon

Reticle Stocker

Mask Shop Device Manufacturer

SHIPPINGSHIPPING

STORAGESTORAGE

EXPOSUREEXPOSURE

ININ--TOOL HANDLINGTOOL HANDLING


Particulate Contamination during ShippingParticulate Contamination during Shipping

Shipping pod

1.1. Pod open/close.Pod open/close.2.2. Direct contact with pedestals, Direct contact with pedestals,

guides, fixtures, guides, fixtures, …… in the pod.in the pod.3.3. Vibration/shock during shipping.Vibration/shock during shipping.4.4. Pod breathing due to atmospheric Pod breathing due to atmospheric

pressure fluctuation.pressure fluctuation.


Particulate Contamination during StorageParticulate Contamination during Storage

1.1. Pod exchange.Pod exchange.•• Pod open/close.Pod open/close.•• Direct contact with pedestals, guides, fixtures, Direct contact with pedestals, guides, fixtures, …… in the pod.in the pod.

2.2. Pod breathing due to atmospheric pressure fluctuation.Pod breathing due to atmospheric pressure fluctuation.3.3. Chemical contamination during storage in the pod.Chemical contamination during storage in the pod.

Storage pod

Reticle Stocker

Shipping pod


Particulate Contamination during InParticulate Contamination during In--tool Handlingtool Handling

1.1. Direct contact with endDirect contact with end-- effectors. effectors.

2.2. Pumping down and venting Pumping down and venting in loadlocks.in loadlocks.

3.3. Direct contact with an Direct contact with an electrostatic chuck.electrostatic chuck.

MaskMask

EndEnd--effectoreffector

MaskMask

LoadlockLoadlock

VentingVenting

Mask

ChuckChuck


Particulate Contamination during ExposureParticulate Contamination during Exposure

1.1. The surface of the reticle is always uncovered and the The surface of the reticle is always uncovered and the stage is running. stage is running.

2.2. Electric charge by external photoelectric effect due to Electric charge by external photoelectric effect due to EUV light emission. EUV light emission.

ChuckChuck

MaskMask

e-

e- e- e-e-

e-

e-

Will not be mentioned any more in this paper.


Proposed EUV PodsProposed EUV Pods

Intel/Fala Bracket w/Mod. RSP200 (Intel/SEMATECH)

EUV mask standards TF, Jul. 2005EUV mask carrier standard workshop, Feb. 2006EUV Mask Technology & Standards Workshop, Oct. 2006

Vacuum Compatible FOUP (Alcatel)

EUV Reticle Storage Box With Frame (ASML)

EUV Pod w/Mod. RSP200 (Canon/Nikon/Entegris)

Vacuum Pod for EUV (TDK)


Proposed EUV PelliclesProposed EUV Pellicles

Removable Pellicle (Lasertec)EUV Mask Technology & Standards Workshop, Oct. 2004

Si Membrane on Mesh (Intel)

CNT Pellicle (SOPRA)

EUV Symposium, Oct. 2006

Removed when wafer exposure.Removed when wafer exposure.

CNTCNTMaskMask

Limited EUV transmittanceLimited EUV transmittance

??????

SPIE Microlithography, 2005


Comparison of Proposed EUV PodsComparison of Proposed EUV Pods

Potential Particulate Contaminating Events

(Intel) Bracket

(CNE) Dual Pod

(ASML) Frame

(Alcatel) Vacuum

(TDK) CAVS

Front side protection Bracket Baseplate (Inner pod) Frame No No

Back side protection No Cover (Inner pod) No No No

Pumping down and venting in loadlocks No Filter Filter Vacuum Vacuum

Designed for Shipping YES YES No YES YES

Selete evaluated "CNE dual pod".Selete evaluated "CNE dual pod".


ContentsContents





CNE Dual PodCNE Dual Pod

• Canon, Nikon and Entegris have started collaboration in 2005 and developed three types of EUV carrier prototypes, alpha, beta and gamma.

– Alpha and beta were tested by SEMATECH in 2005 and 2006.– Gamma is smaller than the others. – Selete started evaluation of beta and gamma in 2007.

Reticle mounted EUV pod (β)

Reticle dismounted EUV pod (β) Closed EUV pod

EUV pod installed RSP

EUV mask carrier standard workshop

@San Jose, Feb. 2006


Packing for Shipping TestPacking for Shipping Test

Two pods vertically packed Box in box packing

Ready to ship Go!!

http://www.jta.or.jp/

Data logger enclosed


Where Shipped To?Where Shipped To?

Selete@Tsukuba

Renesas@HyogoApr. 2007 ~

Rorze@HiroshimaFeb. 2007

Toshiba@OitaMar. 2007 ~

Tokyo Haneda Airport

• Round trip between Tsukuba and Hiroshima, Oita, or Hyogo.


Particle Inspection Tool ~ M3350Particle Inspection Tool ~ M3350

• Lasertec M3350– Sensitivity: 46nm PSL on Qz– Mask flipper– RSP200/CNE pod compatible interface

RSP200/CNE pod

RSP200

Open cassetteMask flipper

M3350 in Selete Inspection result example


1 1

5

10

0.5 1 0.5 1

5

8

5

11

1

4

10 0 0 0 0 0 0 0 0 0

10 0 0 0

0123456789

1011

Bac

k

01234567891011

CrN coated substrates used

0 0 0

10

0 0 0 01 1

0 0 01

0 0 0 0 0 0 0 0 0 0 0 0 01

0 00123456789

1011

Fron

t

01234567891011

Shipping Test SummaryShipping Test Summary

Substrates: Bare Qz blanks (#01-14, 21-30) & CrN coated blanks (#15-20)Inspection area: 142 x 142mm2 Sensitivity: 46nm PSL (Qz), 70-80nm PSL (CrN)

• 3 betas and 7 gammas tested. • Average adders per ship: 0.5@front & 1.9@back

#01

B-1

#02

B-2

#03

G-0

#04

B-3

#05

B-1

#06

B-2

#07

B-1

#08

B-2

#09

G-1

#10

G-2

#11

G-1

#12

G-2

#13

G-1

#14

G-2

#15

G-3

#16

G-4

#17

G-3

#18

G-4

#19

G-3

#20

G-4

#21

G-3

#22

G-4

#23

G-3

#24

G-4

#25

G-5

#26

G-6

#27

G-5

#28

G-6

#29

G-5

#30

G-6


2/16

/07

2/16

/07

2/20

/07

2/20

/07

2/14

/07

2/14

/07

3/28

/07

3/28

/07

4/5/

074/

5/07

6/27

/07

6/27

/07

8/28

/07

8/28

/07

9/27

/07

9/27

/07

11/1

5/07

11/1

5/07

11/2

1/07

11/2

1/07

12/1

2/07

12/1

2/07

1/17

/07

1/17

/07

2/15

/07

2/15

/07

3/11

/07

3/11

/07

3/24

/07

3/24

/07

8/21

/07

8/21

/07

Combination with 7-week storage test

Something improved here?


20

5

11

0 0 0 00123456789

1011

Bac

k

01234567891011

0 0 0 0 0 0 0 00123456789

1011

Fron

t

01234567891011

Storage Test SummaryStorage Test Summary

Substrates: Bare Qz blanks (#101-104, 107-108) & CrN coated blanks (#105-106)Inspection area: 142 x 142mm2 Sensitivity: 46nm PSL (Qz), 70-80nm PSL (CrN)

• 8 CNE pods (2 generations) tested in Selete Class 100 clean room. • Average adders per storage: 0.0@front & 2.3(0.3*1)@back

*1: Real storage (#103&104 excluded)#1

01 B

-1(6

w)

#102

B-2

(6w

)

#103

G-1

(7w

)

#104

G-2

(7w

)

#105

G-3

(7w

)

#106

G-4

(7w

)

#107

G-3

(3w

)

#108

G-4

(3w

)


Combination with shipping test


Individual Shipping Data ~ Front SideIndividual Shipping Data ~ Front Side

#04 B-3 #09 G-1 #10 G-2

4

-75-70-65-60-55-50-45-40-35-30-25-20-15-10-505

1015202530354045505560657075

-75

-70

-65

-60

-55

-50

-45

-40

-35

-30

-25

-20

-15

-10 -5 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75

440

-75-70-65-60-55-50-45-40-35-30-25-20-15-10-505

1015202530354045505560657075

-75

-70

-65

-60

-55

-50

-45

-40

-35

-30

-25

-20

-15

-10 -5 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75

149

-75-70-65-60-55-50-45-40-35-30-25-20-15-10-505

1015202530354045505560657075

-75

-70

-65

-60

-55

-50

-45

-40

-35

-30

-25

-20

-15

-10 -5 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75

3

7

3

3

4

3

33

5

3

-75-70-65-60-55-50-45-40-35-30-25-20-15-10-505

1015202530354045505560657075

-75

-70

-65

-60

-55

-50

-45

-40

-35

-30

-25

-20

-15

-10 -5 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75

38

-75-70-65-60-55-50-45-40-35-30-25-20-15-10-505

1015202530354045505560657075

-75

-70

-65

-60

-55

-50

-45

-40

-35

-30

-25

-20

-15

-10 -5 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75

#14 G-2 #28 G-6

#04: 3pix -> 46nm PSL#09-28: 4pix -> 46nm PSL


Environmental Data Log during Shipping TestEnvironmental Data Log during Shipping Test

• Acceleration, temperature, humidity and air pressure during the shipping test were logged.

0

10

20

30

40

50

60

70

80

90

10015

:00

16:0

017

:00

18:0

019

:00

20:0

021

:00

22:0

023

:00

0:00

1:00

2:00

3:00

4:00

5:00

6:00

7:00

8:00

9:00

10:0

011

:00

12:0

013

:00

14:0

015

:00

16:0

017

:00

18:0

019

:00

20:0

021

:00

Time

Acc

eler

atio

n(G

), Te

mpe

ratu

re(C

) and

Hum

idity

(%)

550

600

650

700

750

800

850

900

950

1000

1050

Air

Pre

ssur

e (h

Pa)

Air Pressure

Humidity

Acceleration

Temperature

Started from SeleteStarted from Selete

Delivery Center in Tokyo

Arrived at Haneda Airport

Arrived at ToshibaArrived at Toshiba

ExampleExample


Drop TestDrop Test

• The acceleration of 40G can be easily generated by dropping a package from a height of 500mm (20inch).

0

10

20

30

40

50

60

0 100 200 300 400 500 600Falling height (mm)

Peak

acc

eler

atio

n (G

)


0

20

40

60

80

100

120

140

160

180

200

Acce

lera

tion

(G),

Tem

pera

ture

(C) a

nd H

umid

ity (%

)

100

200

300

400

500

600

700

800

900

1000

1100

Air

Pre

ssur

e (h

Pa)

Max. Acceleration (G)

Max. Temperature (C)Min. Temperature (C)

Max. Humidity (%)

Min. Humidity (%)

Max. Air Pressure (hPa)

Min. Air Pressure (hPa)

• No correlation found between the number of particle adders and any logged data during shipping tests.

Number of Adders vs. Shipping ConditionNumber of Adders vs. Shipping Condition

0

5

10

15

# of Front side adders

# of Back side addders


1 1

5

10

0.5 1 0.5 1

5

8

5

11

1

4

10 0 0 0 0 0 0 0 0 0

10 0 0 0

0123456789

1011

Bac

k

01234567891011

0 0 0

10

0 0 0 01 1

0 0 01

0 0 0 0 0 0 0 0 0 0 0 0 01

0 00123456789

1011

Fron

t

01234567891011

Potential Reason of the DifferencePotential Reason of the Difference

#01

B-1

#02

B-2

#03

G-0

#04

B-3

#05

B-1

#06

B-2

#07

B-1

#08

B-2

#09

G-1

#10

G-2

#11

G-1

#12

G-2

#13

G-1

#14

G-2

#15

G-3

#16

G-4

#17

G-3

#18

G-4

#19

G-3

#20

G-4

#21

G-3

#22

G-4

#23

G-3

#24

G-4

#25

G-5

#26

G-6

#27

G-5

#28

G-6

#29

G-5

#30

G-6

Pod cleaning procedure improved!Pod cleaning procedure improved!(Verification needed)(Verification needed)


0 0 0 0 0 0 0 0 0 0 0 0 01

0 00123456789

1011

Fron

t

Shipping and Storage Test Results after Pod Cleaning ImprovementShipping and Storage Test Results after Pod Cleaning Improvement

• Average adders per ship: 0.06@front & 0.13@back• Average adders per storage: 0.0@front & 0.0@back

#15

G-3

#16

G-4

#17

G-3

#18

G-4

#19

G-3

#20

G-4

#21

G-3

#22

G-4

#23

G-3

#24

G-4

#25

G-5

#26

G-6

#27

G-5

#28

G-6

#29

G-5

#30

G-6


Substrates: Bare Qz blanks (#21-30, 107&108) & CrN coated blanks (#15-20, 105&106)Inspection area: 142 x 142mm2 Sensitivity: 46nm PSL (Qz), 70-80nm PSL (CrN)

0 0 0 00123456789

1011

10 0 0 0 0 0 0 0 0 0

10 0 0 0

0123456789

1011

Fron

t

0 0 0 00123456789

1011

#105

G-3

(7w

)#1

06 G

-4(7

w)

#107

G-3

(3w

)#1

08 G

-4(3

w)


Shipping Storage


MPE ToolMPE ToolMPE Tool = Mask Protection Engineering Tool

PhotoRSP200RSP200

VacuumVacuum

AirAir

ESCESC

L/LL/L

Inner cassette Inner cassette opener/stockeropener/stocker RSP200RSP200

Inner cassette Inner cassette opener /stockeropener /stocker

ReservedReservedReservedReserved

ReservedReserved

Schematic Diagram

EFEM


CNE Dual Pod RSP200

(1) Air & Loadlock 0.005 (666) @A 0.004 (900) @B

(２）Vacuum path 0 (200) @C 0.015 (200) @D

(３）Full path 0.008 (900) @E 0.028 (250) @F

(４) ESC contact 0 (360）@G1 0.024 (288) @G2

Total path(3)+(4) 0.008 0.052Sensitivity: ≥

46 nm PSLArea: 142 x 142 mm2

Using the CNE dual pod, the number of particle adders Using the CNE dual pod, the number of particle adders per 100 trips was less than 1 ( per 100 trips was less than 1 ( ≥≥

46nm PSL). 46nm PSL).

Number of particle adders per round trip shown. Total number of trips shown in brackets( ).

(2)C

D

Baseplate

(4)G Chuck

Chuck

G1

G2

(3)(1)

ABE

F

InIn--Tool Handling Evaluation of CNE Dual PodTool Handling Evaluation of CNE Dual Pod

Substrate


Flatness Measurement SetupFlatness Measurement Setup

Zygo interferometer has been installed in MPE Tool.

ESCMask

Zygo Interferometer

ESC Chamber

Fizeau flatFizeau flat

MPE ToolMPE Tool

Zygo InterferometerZygo Interferometer


Propagation Length of Particle Induced OPDPropagation Length of Particle Induced OPD• The initial peak height (not particle height) was about 800 nm at

80V(20kPa); the peak almost disappeared at 640V(310kPa); the peak came back again at 80V(20kPa) but the height ~400nm is half of the initial height.

(1) 80V (2) 160V (3) 320V (4) 640V

(7) 80V (6) 160V (5) 320V

The peak height was about 800 nm at the beginning.The OPD spread about 28mm.

(1) – (4) r = 28mm

Zmax = 740nmZmin = -245nmPower component removed.


OPD Evaluation using Programmed ParticlesOPD Evaluation using Programmed Particles• The reticle OPD was evaluated using two types of programmed particles:

carbon particles (1&5 μm) and quartz glass particles (1&3 μm). • The programmed particles were crashed or embedded into the substrates and

no OPD was observed.

Before chuckBefore chuck After chuckAfter chuck

Before chuckBefore chuck After chuckAfter chuck

+ 5nm

- 5nm

rms 0.54 nmPV 7.9 nm

5μm(H) 1μm(H)

No OPD observed.

High pass filtered (>0.1mm-1)Chucking pressure: 20kPa (80V)

55μμm(H)m(H)55μμm(D)m(D)

55μμm(W)m(W)

11μμm(H)m(H)55μμm(D)m(D)

55μμm(W)m(W)


ContentsContents





SEMI Standardization in ProgressSEMI Standardization in Progress

• SEMI draft document 4466, "MECHANICAL SPECIFICATION FOR A 150mm EUVL RETICLE SMIF POD (EUV Pod)"

– Blue ballot in June 2007 and yellow ballot in February 2008.

SEMI Draft Document 4466 (Yellow) 2008

Figure 7. Inner Pod – Internal Side View

Figure 1. Exploded View Of Carrier And Inner Pod


Backside Contamination by ChuckingBackside Contamination by Chucking

100,0002921,343 100,000

Chuck A Chuck B

• Particle traveling back to front may be an issue.

Sensitivity: 500nm-1μm (uncertain) Sensitivity: 72nm PSL@2pix

Inspection stopped due to saturation of number of particles.


Other IssuesOther Issues

• Pod cleaning and inspection– Pod cleanliness is a key to pellicle-less reticle handling. – How to clean and how to inspect are important.

• Elemental analysis of a small particle– EDS cannot detect small particles < 100nm.

• Inspection tool issues – Higher sensitivity required. – Particle adders in inspection tools are not negligible.

Cleanliness of defect inspection tools has to be improved.


SummarySummary

• "Reticle protection during storage, handling and use" is one of the critical issues of EUV lithography and many EUV pods were proposed to find the solution.

• Selete has evaluated "CNE pod" developed by Canon, Nikon and Entegris and found that it had very promising protecting performance during shipping, storage and in-tool handling.

– Adders in shipping: 0.06/ship@front (16 trips)0.13/ship@back (16 trips)

– Adders in storage: 0.0/event@front (4 events)0.0/event@back (4 events)

– Adders in in-tool handling: 0.008/path@front• Reticle backside contamination by electrostatic chucks,

pod cleaning, pod inspection, elemental analysis of a small particle and improvement of inspection tool cleanliness are issues.


AcknowledgementsAcknowledgements

CNE team: Yoshio Gomei, Canon

Tsuneyuki Hagiwara, NikonKazuaki Suzuki, Nikon

David Halbmaier, EntegrisJohn Lystad, Entegris

Shipping test cooperator: Shigeru Hasebe, Toshiba

Shuichi Matsuda, RenesasHisato Ogawa, Rorze

This work was supported by NEDO.

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