A 45nm Logic Technology with High-k + Metal Gate Transistors, Strained Silicon, 9 Cu

Interconnect Layers, 193nm Dry Patterning, and 100% Pb-free Packaging

K. Mistry, C. Allen, C. Auth, B. Beattie, D. Bergstrom, M. Bost, M. Brazier, M. Buehler, A. Cappellani, R. Chau*, C.-H. Choi, G. Ding, K. Fischer, T. Ghani, R. Grover, W. Han, D. Hanken, M. Hattendorf, J. He#, J. Hicks#, R. Heussner, D. Ingerly, P. Jain, R. James, L. Jong, S. Joshi, C. Kenyon, K. Kuhn, K. Lee,

H. Liu, J. Maiz#, B. McIntyre, P. Moon, J. Neirynck, S. Pae#, C. Parker, D. Parsons, C. Prasad#, L. Pipes, M. Prince, P. Ranade, T. Reynolds,

J. Sandford, L. Shifren%, J. Sebastian, J. Seiple, D. Simon, S. Sivakumar, P. Smith, C. Thomas, T. Troeger, P. Vandervoorn, S. Williams, K. Zawadzki

Portland Technology Development, *CR, #QRE, %PTMIntel Corporation

2

Outline

• Introduction• Process Features• Transistors• Interconnects• Manufacturing• Conclusions

3

Introduction• SiON scaling running out of atoms• Poly depletion limits inversion TOX scaling

1

10

350nm 250nm 180nm 130nm 90nm 65nm

Elec

trica

l (In

v) T

ox (n

m)

0.01

0.1

1

10

100

1000

Gat

e Le

akag

e (R

el.)

Silicon

Poly

SiON

4

High-k + Metal Gate Benefits• High-k gate dielectric

– Reduced gate leakage– TOX scaling

• Metal gates– Eliminate polysilicon depletion– Resolves VT pinning and poor mobility

for high-k dielectrics

5

High-k + Metal Gate Challenges• High-k gate dielectric

– Poor mobility, VT pinning due to soft optical phonons

– Poor reliability

• Metal gates– Dual bandedge workfunctions– Thermal stability– Integration scheme

6

Outline

• Introduction• Process Features• Transistors • Interconnects• Manufacturing• Conclusions

7

Process Features

• 45 nm Groundrules• 193 nm Dry Lithography• High-K + Metal Gate Transistors• 3RD Generation Strained Silicon• Trench Contacts with Local Routing• 9 Cu Interconnect Layers• 100% Lead-free Packaging

8

Process Features

• 45 nm Groundrules• 193 nm Dry Lithography• High-K + Metal Gate Transistors• 3RD Generation Strained Silicon• Trench Contacts with Local Routing• 9 Cu Interconnect Layers• 100% Lead-free Packaging

9

45nm Design Rules

~0.7x linear scaling from 65nm

Layer Pitch (nm) Thick (nm) Aspect RatioIsolation 200 200

60144144144216252324

Metal 7 560 504 1.8Metal 8 810 720 1.8

7μm

--Contacted Gate 160 --Metal 1 160 1.8Metal 2 160 1.8Metal 3 160 1.8Metal 4 240 1.8Metal 5 280 1.8Metal 6 360 1.8

Metal 9 30.5μm 0.4

Contacted Gate Pitch• Transistor gate pitch of 160 nm continues

0.7x per generation scaling

Tightest contacted gate pitch reported for 45 nm generation

100

1000

250nm 180nm 130nm 90nm 65nm 45nm

Technology Node

Con

tact

ed G

ate

Pitc

h (n

m)

0.7x every 2 yearsPitch

11

SRAM Cells• 0.346 μm2 and 0.382 μm2 SRAM cells

– Optimize density and power/performance

Transistor density doubles every two years

0.1

1

10

250nm 180nm 130nm 90nm 65nm 45nm

Technology Node

SRA

M C

ell S

ize

( μm

2 )

0.5x every 2 years

12

SRAM Array Density• SRAM array density achieves 1.9 Mb/mm2

– Includes row/column drivers and other circuitry

Array density scales at ~2X per generation

1.9 Mb/mm2

0.1

1.0

10.0

90nm 65nm 45nmSRA

M A

rray

Den

sity

(Mb/

mm

2 )

13

Outline

• Introduction• Process Features• Transistors• Interconnects• Manufacturing• Conclusions

14

Transistor Process Flow• Key considerations

– Integrate hafnium-based high-k dielectric, dual metal gate electrodes, strained silicon

– Thermal stability of metal gate electrodes

• High-k First, Metal Gate Last– Metal gate deposition after high temperature

anneals– Integrated with strained silicon process– Transistor mask count same as 65nm

15a

Transistor Process Flow

p-well N-well

STI

Standard process except for ALD high-k

n-ext n-ext p-ext p-ext

High-k High-k

Dummy Polysilicon

15b

Transistor Process Flow

p-well N-well

STI

e-SiGe & S/D, Thermal anneal, ILD0 deposition

N+ N+ SiGeSiGe

ILD0

STI

15c

Transistor Process Flow

p-well N-well

STI

Poly Opening Polish

N+ N+ SiGeSiGeSTI

15d

Transistor Process Flow

p-well N-well

STI

Dummy Poly removal

N+ N+ SiGeSiGeSTI

15e

Transistor Process Flow

p-well N-well

STI

PMOS WF Metal deposition

N+ N+ SiGeSiGeSTI

15f

Transistor Process Flow

p-well N-well

STI

PMOS WF Metal patterning

N+ N+ SiGeSiGeSTI

15g

Transistor Process Flow

p-well N-well

STI

NMOS WF Metal deposition

N+ N+ SiGeSiGeSTI

15h

Transistor Process Flow

p-well N-well

STI

Metal Gate trenches filled with low resistance Al

N+ N+ SiGeSiGe

Al fill

STI

15i

Transistor Process Flow

p-well N-well

STI

Metal Gate Polish

N+ N+ SiGeSiGeSTI

15j

Transistor Process Flow

p-well N-well

STIN+ N+ SiGeSiGeSTI

High-k High-k

NMOS WF PMOS WF

Low Resistance Al Fill

High-k + Metal gate transistor formation complete

16

Transistor Features

• 35 nm min. gate length• 160 nm contacted gate

pitch

• 1.0 nm EOT Hi-K• Dual workfunction

metal gate electrodes

• 3RD generation of strained silicon

17

Gate Leakage • Gate leakage is reduced >25X for NMOS

and 1000X for PMOS

0.00001

0.0001

0.001

0.01

0.1

1

10

100

-1.2 -1 -0.8 -0.6 -0.4 -0.2 0 0.2 0.4 0.6 0.8 1 1.2

VGS (V)

Nor

mal

ized

Gat

e Le

akag

e SiON/Poly 65nm

HiK+MG 45nm

NMOS PMOS

HiK+MG 45nm

SiON/Poly 65nm

65nm: Bai, 2004 IEDM

18

Optimal Workfunction Metals• Excellent VT rolloff and DIBL

NMOS PMOS

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

0.40

0.45

0.50

30 35 40 45 50 55 60LGATE (nm)

Thre

shol

d Vo

ltage

(V)

|VDS|= 1.0V

|VDS|= 0.05V

-0.50

-0.45

-0.40

-0.35

-0.30

-0.25

-0.20

-0.15

-0.10

-0.05

0.00

30 35 40 45 50 55 60LGATE (nm)

Thre

shol

d Vo

ltage

(V)

|VDS|= 1.0V

|VDS|= 0.05V

19

3RD Generation Strained Silicon

• Increased Gefraction– 90 nm: 17% Ge– 65 nm: 23% Ge– 45 nm: 30% Ge

• SiGe closer to channel

20

NMOS IDSAT vs. IOFF

1.36 mA/μm at IOFF = 100 nA/μm12% better than 65 nm

1

10

100

1000

0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5 1.6IDSAT (mA/μm)

IOFF

(nA

/ μm

)

65 nm

VDD = 1.0V

90 nm

160 nm

90nm: Mistry 2004 VLSI65nm: Tyagi, 2005 IEDM

21

PMOS IDSAT vs. IOFF

1.07 mA/μm at IOFF = 100 nA/μm51% better than 65 nm

1

10

100

1000

0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3IDSAT (mA/μm)

IOFF

(nA

/ μm

)

65 nm

VDD = 1.0V

90 nm

160 nm

90nm: Mistry 2004 VLSI65nm: Tyagi, 2005 IEDM

22

Transistor Performance vs. Gate Pitch

Simultaneous performance and density improvement

90nm: Mistry, 2004 VLSI65nm: Tyagi, 2005 IEDM

1001000 Contacted Gate Pitch (nm)

IDSA

T (m

A/ μ

m)

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

PMOS

NMOS

160nm (45nm)

220nm (65nm)

320nm (90nm)

1.0V, 100 nA/μm

Gate Pitch (Generation)

23

Ring Oscillator Performance

3

4

5

6

7

8

9

10 100 1000 10000IOFFN + IOFFP (nA/um)

DEL

AY

PER

STA

GE

(pS)

65nm @ 1.2V

45nm @1.1V

Fanout = 2

FO=2 delay of 5.1 ps at IOFFN = IOFFP = 100 nA/μm23% better than 65 nm at the same leakage

24

Transistor Reliability Challenges

• Defect types in SiO2 have been studied for decades

• New defect types for high-k need to be suppressed

• TINV scaled ~0.7X relative to 65 nm– Need to support 30% higher E-field

25

Transistor Reliability - TDDB

45nm High-k + Metal Gate supports 30% higher E-field

1.E+02

1.E+03

1.E+04

1.E+05

1.E+06

1.E+07

1.E+08

1.E+09

4 6 8 10 12 14 16Field (MV/cm)

TDD

B (s

ec)

SiON/Poly 65nm

45nmHK+MG

65nm: Bai, 2004 IEDM

26

Transistor Reliability: Bias Temperature

0

10

20

30

40

50

5 7 9 11 13SiO2 equivalent EField (MV/cm)

Vt i

ncre

ase

(mV

)

SiON/Poly 65nm

45nm HK+MG

PMOS NBTI

0

10

20

30

40

50

5 7 9 11 13SiO2 equivalent EField (MV/cm)

Vt i

ncre

ase

(mV

)

45nm HK+MG

SiON/Poly65nm

NMOS PBTI

PMOS NBTI 45 nm Hi-k + MG supports 50% higher E-field

NMOS PBTI 45 nm Hi-k + MG supports 15% higher E-field

65nm: Bai, 2004 IEDM

27

Outline

• Introduction• Process Features• Transistors• Interconnects• Manufacturing• Conclusions

28

Interconnects • Metal 1-3 pitches

match transistor pitch

• Graduated upper level pitches optimize density & performance

• Lower layer SiCNetch stop layer thinned 50% relative to 65 nm

• Extensive use of low-k ILD

MT1MT2MT3

MT7

MT4

MT5

MT8

MT6

CDOCDOCDO

CDO

CDO

CDO

CDO

SiO2

29

Metal 9: ReDistribution Layer (RDL) • Metal 9 RDL: 7um thick with polymer ILD

– Improved on-die power distribution

Polymer ILD

Cu Bump

Metal 9

MT8MT7

7 μm

30

100% Lead Free Packaging

Cu Bump

Sn/Ag/Cu Solder

Cu Pad

45 nm

65 nm

Cu Bump

Pb/Sn Solder

Cu Pad

90 nm

Pb Bump

Cu Pad

Pb/Sn Solder

• Environmental benefit, lower SER

31

Outline

• Introduction• Process Features• Transistors• Interconnects• Manufacturing• Conclusions

32

153Mb SRAM Test Vehicle• Process learning vehicle demonstrates

– High yield– High performance– Stable low voltage operation

1.3V |***************************** .

1.2V |************************** .

1.1V |************************* .

1.0V |********************** .

0.9V |**************** . .

0.8V |****** . . .+---------+---------+---------+1.8GHz 2.3GHz 3.2GHz 5.3GHz

3.8GHz

2GHz

4.7GHz

0.346 μm2 SRAM Cell>1 billion transistors

Fully functional Jan’06

33

Multiple Microprocessors

Single Core

Dual Core

Quad Core

Defect Reduction Trend• Mature yield demonstrated 2 years after 65 nm

Defect Density (log scale)

2000 2001 2002 2003 2004 2005 2006 2007 2008

130 nm 90 nm 65 nm 45 nm

Defect Reduction Trend• Mature yield demonstrated 2 years after 65 nm• Matched yield in 2ND Fab – Copy Exactly!

Defect Density (log scale)

2000 2001 2002 2003 2004 2005 2006 2007 2008

F32

130 nm 90 nm 65 nm 45 nm

35

Conclusions• A 45 nm technology is described with

– Design rules supporting ~2X improvement in transistor density– 193nm dry lithography at critical layers for low cost– Trench contacts supporting local routing– 8 standard Cu interconnect layers with extensive use of low-k– Thick Metal 9 Cu RDL with polymer ILD

• High-k + Metal gate transistors implemented for the first time in a high volume manufacturing process– Integrated with 3RD generation strained silicon– Achieve record drive currents at low IOFF and tight gate pitch

• The technology is already in high volume manufacturing– High yields demonstrated on SRAM and 3 microprocessors– High yields demonstrated in two 300mm fabs

36

Acknowledgements

• The authors gratefully acknowledge the many people in the following organizations at Intel who contributed to this work:– Portland Technology Development – Quality and Reliability Engineering– Process & Technology Modeling– Assembly & Test Technology Development

37

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