Miniaturization and advanced optical lithography · 32nm half-pitch poly-Si gates etched using double ... Institut de Microelectrònica de Barcelona Escuela de verano de Jaca July

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Institut de Microelectrònica de Barcelona

Escuela de verano de Jaca July 2011

Miniaturization and advanced optical

lithography

Francesc Pérez-Murano

Institut de Microelectrònica de Barcelona (CNM-IMB, CSIC)

[email protected]

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Integrated circuits (Microelectronics Industry)

Massive nanofabricationMassive nanofabrication

PanasonicIntel

High production capabilities

Extremely complex and expensive

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Transistor MOS = Miniaturized transistor

Attalla and Kang, 1.960

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State of the art TMOS transitorIEDM 2009

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State of the art TMOS transitorIEDM 2009

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1947W. Shockley, J. Bardeen W. Brattain

FIRST TRANSISTOR

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1958: First integrated circuit

Jack S. Kilby

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Escuela de verano de Jaca July 2011 10/68



Cross Section of Panasonic 65nm CMOSCross Section of Panasonic 65nm CMOS

5th Cu4th Cu3rd Cu2nd Cu1st Cu

Cu

Low-k

STI

6th Cu

7th Cu

Min. hp90nmM2, hp100nm

Cross Section of TransistorCross Section of Transistor

55nmNiSi

O2-

Si4+

0.227nm0.162nm

Θ= 120～180°Si

substrate

1.8nmSiO2

poly-Si

Gate dielectrics film

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CMOS Technology Processes

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The number of transistors per chip The number of transistors per chip doubles every two yearsdoubles every two years

MOORE’s LAW

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Limits of optical lithography

Minimum transfer feature= k1·(wavelength)/(numerical aperture)

k1 depends on technology and instrumental parametersNA: Numerical aperture = n·sin

K1=0.8, = 436 nm, NA=0.4

K1=0.4, = 193 nm, NA=0.7

Resolution= 872 nm

Resolution= 110 nm

1988

2004

K1=0.22, = 193 nm, NA=1.35 Resolution= 32 nm2010

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IC LSI VLSI ULSI Nano-LSI10m

1m

100nm

10nm

ContactAligner

1:1 ProjectionAligner

Stepper Scanner NGL

Device Trends and Exposure Tool

g-line (436nm)i-line (365nm)KrF (248nm)ArF (193nm)ArF Immersion

Device Trend(134nm)

Immersion lithography is introduced from 45nm-node

Half-pitch = k1λNA

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dry immersion

resist

lens

light light

reflectionAll

reflection

NA limitation（NA＜1.0）

fluid (water)

Higher NA（NA 1.0）

waferAir

Incident angle

Using an immersion fluid between the wafer and the lens substantially changes the light path, resulting in two benefits. First, it enhances depth of focus (DOF) for a given Numerical Aperture. Second, immersion allows lens designs with Numerical Apertures significantly larger than 1.0, therefore allowing improved resolution. NA<1: Gain in DoF due to the smaller angles in water.NA>1: Only feasible for immersion. Dry lenses would show total reflection at last surface. With immersion lenses smaller CDs can be resolved. Resolution enhancement !

Principles of Immersion Lithography22/68



http://www.itrs.net

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Double patterning techniques

Pitch doubling Double exposure

11 nm channgel length achievable with immersion lithography

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11 nm channgel length achievable with immersion lithography

Double patterning techniques

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32nm half-pitch poly-Si gates etched using double

pattering

© IMEC

Self-aligned double patterning 22 nm half pitch

© Applied Materials

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© NIKON

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Design (Logic) Design (SRAM)(Red Photo GATEline, Green photo GATEcut, yellow is ACTIVE)

Double patterning @ 45 nm

Documents

Miniaturization and advanced optical lithography · 32nm half-pitch poly-Si gates etched using double ... Institut de Microelectrònica de Barcelona Escuela de verano de Jaca July