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Photomask Technology Challenges at the 45nm Node

Patrick Martin

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Mask Materials and Infrastructure

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Significance of 193nm Immersion to Mask Making

Materials Engineering

nki)k(nne 2222~~ +−==

λπkd

eRODonTransmissi4

)1(10−

−=−=

∆φ = (2π / λ)(ni-1) t

( )22

1min

NAk

DOF

NAk

R

λ

λ

=

=

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Significance of 193nm Immersion to Mask Making

Fused SiO2Low Birefringence

Absorber

ARC (Reflectivity)

Pellicle

193nm WetλAttribute

157nm (Dry)

193nm Dry

Attenuator (PSM)Variable T%

Substrate Fused SiO2Low Birefringence

F2 Doped

Chrome,Other

Fused SiO2

TBD %

Chrome,Other

MoSi,Other

<5%15 – 20 %

Organic

SiON + MNMoSi,Other

Chrome

Fused SiOrganic

Avoidance: Process Development/Integration of 157nmOpportunity: Material Properties for Immersion

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Limiting Industry Trends

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0.9

1

2001 2002 2003 2004 2005 2006 2007 2008 2009 2010

Nor

mal

ized

Inde

x

130nm

90nm

65nm

45nm Est

Mask Unit

# of SemiconductorCompanies

ASIC Design Starts

Development cycles are accelerating, but everything elseis going in the wrong direction!!! Source: Dataquest

Photronics estimate

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Cost Drivers

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Equipment

Repair and Disposition

Inspection

Write Platform

No Known Solution

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Impact of Model-Based OPC

§ Nominal design is shaded.§ OPC version is fractured into rectangles.§ Up to 10× increase in shape count when OPC applied.§ Several hundred billion geometries on mask at 100 nm node.

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Vector Tool Write Time ImpactD

esig

nV

ecto

r

Model-Based OPCRule-Based OPCNo OPC

12 Shots 27 Shots2 Shots

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Write Time vs. Complexity

§ A 90nm device with very aggressive OPC can take up to 20 hrs to write on a $15 million E-beam tool.

0

100

200

300

400

500

600

Via(Optical)

Contact(EB)

Metal (EB)

Active(EB)

Gate (EB)

Wri

te T

ime

(min

ute

s)

130nm90nm65nm

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# Layers by Stepper Wavelength

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5

10

15

20

25

30

35

40

45

DRAM Logic

193nm/193i248nmi-line

180nm130nm 110nm

90nm

65nm

180nm 130nm

90nm

65nm

Lay

ers

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0.5

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0.9

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B1 B2 B3 B4 B5 B6 B7 B8 B8 E1 E2 E3 A1 A2 C1Product Type

No

rmal

ized

Pri

ce

Cost vs. Complexity

180nm

130nm

90nm

Code: B = Binary, E = EAPSM, A = AAPSM, C = CPL

65nm

130nm

90nm

90nm

65nm

No OPC, 248nm Mild OPC, 193nm Aggressive OPC, 193nm

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Mask Cost for 45nmØ General Assumptionsü 193nm wet compared to 157nm dry

§ 193nm Dry Not Capable of 45nm

ü 7 year depreciation model on cap ex of ~70 M$ü Single Line, No Redundancyü 3 layer AAPSM, 12 layer EAPSM, 22 Layer BIMü First three years of engagement (not mature)

ü Moderate OPC, k1 ≤ 0.35 on critical layersü 8 customers total, 3 captiveü 12 Tape Outs

2.5 – 3.5 x/90nm Set

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Mask Cost is only 8% of the Overall Problem

Wafers1%

Boards2% Masks

8%

Software28%

Apps3%

Test Engineering

7%

Product Engineering

12%

I/O Design5%

Logic Design34%

Source: Synopsys, Altera, 90nm Node

The only way to bring the development cost down is to have all involved work together.

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Integrating the Lithography Plane(ILP)

Electrical Design

Design Layout

Mask Build

Do over !

Wafer Build Is it OK ?

$$$$ wasted assilicon piles up on the floor

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0

0.5

1

1.5

2

2.5

3

4X 180nm 4X 90nm 8X 90nm

No

rmal

ized

Mas

t S

et C

ost

(1)

EAPSM 193nmBinary 193nmEAPSM 248nmBinary 248nmBinary 365nm

Increase Magnification, Reduce Field Size

§ If magnification increases to 8X, current 180nm process and tool set can be used for 90nm production.

+ 7X+ 3X

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Summary

§ Advantages of 193nm Immersion Lithography§ Single Wavelength Solution through 2009§ Simplification of Materials; blank and pellicle§ Simplification of Internal Process Development

and Integration§ Overall Cost Benefit vs. 157nm Dry

§ Opportunity§ Integration with Design and Reticle Enhancement

Technology is Key to Cost Minimization§ Small Field § Higher Magnification, 4x – 8x reduction ratio§ Reduced Field Size