Applied Materials Confidential SILICON SYSTEMS GROUP

Precision Materials Engineering

for Advanced Memory: Plasma Treatments of

Thin, Conformal Films

Matthew Spuller, Ph.D.

GPM, Front End Products Group

Date: March 5, 2013

Applied Materials Confidential

R 140

G 140

B 140

R 220

G 220

B 220

R 69

G 153

B 195

R 254

G 203

B 0

R 255

G 121

B 1

R 234

G 40

B 57

R 155

G 238

B 255

R 146

G 212

B 0

R 75

G 75

B 75

R 6

G 30

B 60

SILICON SYSTEMS GROUP

Agenda

Industry moves to ALD

ALD film quality

Improved film quality with plasma treatments

Hardware for plasma treatments

Conformality

2

Applied Materials Confidential

R 140

G 140

B 140

R 220

G 220

B 220

R 69

G 153

B 195

R 254

G 203

B 0

R 255

G 121

B 1

R 234

G 40

B 57

R 155

G 238

B 255

R 146

G 212

B 0

R 75

G 75

B 75

R 6

G 30

B 60

SILICON SYSTEMS GROUP SILICON SYSTEMS GROUP

New ALD Applications in Memory

Top and bottom

Intergate Dielectric

HfO2

Multiple Application of ALD With Memory Inflections

Peripheral transistor

HfO2

Oxide/Nitride

Spacers

High k

blocking

dielectric

Tunnel Oxide

Charge Trap

Layer

Planar Floating Gate NAND

Advanced DRAM 3D Vertical NAND

High-k

High k Interface Layer

Metal Gate

Resistivity

modulation

layer

ReRAM

Intel-Micron 20nm NAND, IEDM, 2013

Toshiba 3D NAND: VLSI, 2009

Applied Materials Confidential

R 140

G 140

B 140

R 220

G 220

B 220

R 69

G 153

B 195

R 254

G 203

B 0

R 255

G 121

B 1

R 234

G 40

B 57

R 155

G 238

B 255

R 146

G 212

B 0

R 75

G 75

B 75

R 6

G 30

B 60

SILICON SYSTEMS GROUP

Key Film Properties Of Conformal Thin Films

ALD SiO2 leakage

ALD Si3N4 wet etch rate

ALD HfO2 thermal stability

4

1.E-09

1.E-07

1.E-05

1.E-03

1.E-01

0 5 10

Cu

rren

t D

en

sit

y

(A/c

m2)

Field (MV/cm)

Reference ALD Oxide

Reference

Thermal Oxide

~10MV/cm

Post 800C Anneal

As deposited HfO2

HfO2 Crystallization

0

5

10

15

20

25

ALD CVD

We

t E

tch

Ra

te R

ati

o

Treatments Are Required For Improving Material Properties M

on

oclin

ic

Cu

bic

All Figures: AMAT data

Applied Materials Confidential

R 140

G 140

B 140

R 220

G 220

B 220

R 69

G 153

B 195

R 254

G 203

B 0

R 255

G 121

B 1

R 234

G 40

B 57

R 155

G 238

B 255

R 146

G 212

B 0

R 75

G 75

B 75

R 6

G 30

B 60

SILICON SYSTEMS GROUP

ICP Plasma For PME of Thin Conformal Films

Requirements:

– Improved Film Quality

– Conformality

– Thickness control

ICP Plasma provides

– High density plasma for effective film treatments

– Low ion energy for ultra thin films

– Versatility of plasma chemistry (N-, O-based)

– Low temperature treatments

5

Plasma Process Tunability Determines Ion and Radical Energy and Density

Applied Materials Confidential

R 140

G 140

B 140

R 220

G 220

B 220

R 69

G 153

B 195

R 254

G 203

B 0

R 255

G 121

B 1

R 234

G 40

B 57

R 155

G 238

B 255

R 146

G 212

B 0

R 75

G 75

B 75

R 6

G 30

B 60

SILICON SYSTEMS GROUP

Properties for Conformal Thin Films With PME ALD SiO2 + Plasma Oxidation

6

1.E-11

1.E-10

1.E-09

1.E-08

1.E-07

1.E-06

1.E-05

1.E-04

1.E-03

1.E-02

1.E-01

1.E+00

0 5 10 15

Cu

rren

t D

en

sit

y (

A/c

m2)

Field (MV/cm)

ALD With DPO Treatment

Reference ALD Oxide

Large Improvement In Both Leakage, Breakdown, and Wet Etch Rate With

Plasma Oxidation Treatment

ALD with Plasma Oxidation Treatment

10

2

0

2

4

6

8

10

12

ALD (As Dep) + O2 Plasma

WE

RR

(vs

Th

erm

al O

xid

e)

All Figures: AMAT data

Applied Materials Confidential

R 140

G 140

B 140

R 220

G 220

B 220

R 69

G 153

B 195

R 254

G 203

B 0

R 255

G 121

B 1

R 234

G 40

B 57

R 155

G 238

B 255

R 146

G 212

B 0

R 75

G 75

B 75

R 6

G 30

B 60

SILICON SYSTEMS GROUP

37.8

41.5

46.8

30

35

40

45

50

ALD (As Dep) + N2 PlasmaRT

+ N2 Plasma400C

N-C

on

ten

t (X

PS

, %

)

Properties for Conformal Thin Films With PME ALD Si3N4 + Plasma Nitridation

32

0.5 0.2 0

5

10

15

20

25

30

35

ALD (As Dep) + N2 PlasmaRT

+ N2 Plasma400C

WE

RR

(vs

Th

erm

al

Ox

ide

)

Increases N-Content

>100X Improvement In

Wet Etch Rate

4.8

7.4 8.3

0

2

4

6

8

10

ALD (As Dep) + N2 PlasmaRT

+ N2 Plasma400C

Bre

ak

do

wn

Vo

lta

ge

(d

MV

/cm

)

Enhanced breakdonw

and leakage

RT = room temperature

Large Improvement In Wet Etch and Electrical Properties With Plasma

Nitridation Treatment All Figures: AMAT data

Applied Materials Confidential

R 140

G 140

B 140

R 220

G 220

B 220

R 69

G 153

B 195

R 254

G 203

B 0

R 255

G 121

B 1

R 234

G 40

B 57

R 155

G 238

B 255

R 146

G 212

B 0

R 75

G 75

B 75

R 6

G 30

B 60

SILICON SYSTEMS GROUP

Properties for Conformal Thin Films With PME ALD HfO2 + Plasma Nitridation

8

Baseline

EOT (Å)

Jg (

A/c

m2)

1Å

1 d

ecade

Hi N%

Low N%

Plasma Nitridation Improves Jg/EOT

Source: Applied Materials

Post 800C

Anneal

HfO2 Crystallization

Monoclin

ic

Cubic

As deposited

N2 Plasma

+ 800C

Anneal

Plasma Nitridation Improves Leakage Through Suppression of Crystallization All Figures: AMAT data

Applied Materials Confidential

R 140

G 140

B 140

R 220

G 220

B 220

R 69

G 153

B 195

R 254

G 203

B 0

R 255

G 121

B 1

R 234

G 40

B 57

R 155

G 238

B 255

R 146

G 212

B 0

R 75

G 75

B 75

R 6

G 30

B 60

SILICON SYSTEMS GROUP SILICON SYSTEMS GROUP

Sidewall Plasma Treatment

Material As Deposited Material With Sidewall

Plasma Treatment Material With Directional

Plasma Treatment

Untreated Material Treated Material

Applied Materials Confidential

R 140

G 140

B 140

R 220

G 220

B 220

R 69

G 153

B 195

R 254

G 203

B 0

R 255

G 121

B 1

R 234

G 40

B 57

R 155

G 238

B 255

R 146

G 212

B 0

R 75

G 75

B 75

R 6

G 30

B 60

SILICON SYSTEMS GROUP SILICON SYSTEMS GROUP

ALD As Deposited

Sidewall Plasma Treatment of ALD Oxide

ALD Oxide Without

Sidewall Plasma

Oxidation

ALD Oxide With

Sidewall Plasma

Oxidation by ICP

After Wet Etch DHF

Plasma Oxidation by ICP Enables Effective Sidewall Treatments All Figures: AMAT data

Applied Materials Confidential

R 140

G 140

B 140

R 220

G 220

B 220

R 69

G 153

B 195

R 254

G 203

B 0

R 255

G 121

B 1

R 234

G 40

B 57

R 155

G 238

B 255

R 146

G 212

B 0

R 75

G 75

B 75

R 6

G 30

B 60

SILICON SYSTEMS GROUP SILICON SYSTEMS GROUP

ALD As Deposited

Sidewall Plasma Treatment of ALD Nitride

ALD Nitride Without

Sidewall Plasma

Nitridation

ALD Nitride With

Sidewall Plasma

Nitridation By ICP

After Wet Etch DHF

Plasma Nitridation by ICP Enables Effective Sidewall Treatments All Figures: AMAT data

Applied Materials Confidential

R 140

G 140

B 140

R 220

G 220

B 220

R 69

G 153

B 195

R 254

G 203

B 0

R 255

G 121

B 1

R 234

G 40

B 57

R 155

G 238

B 255

R 146

G 212

B 0

R 75

G 75

B 75

R 6

G 30

B 60

SILICON SYSTEMS GROUP SILICON SYSTEMS GROUP

Sidewall Treatment With ICP Plasma

12

±20° angular

distribution

Monte

Carlo

Simulation (Ion trajectory)

Plasma Nitridation by ICP Enables High Quality ALD Sidewall Material By Ion-

Assisted Treatment To ~10:1 AR

10:1

Aspect

Ratio

Feature

Ions Impinge Upon

Entire Sidewall

All Figures: AMAT data

Applied Materials Confidential

R 140

G 140

B 140

R 220

G 220

B 220

R 69

G 153

B 195

R 254

G 203

B 0

R 255

G 121

B 1

R 234

G 40

B 57

R 155

G 238

B 255

R 146

G 212

B 0

R 75

G 75

B 75

R 6

G 30

B 60

SILICON SYSTEMS GROUP SILICON SYSTEMS GROUP

N-Doping Conformality Study Test Methodology

Structure wafers with nominal 32nm fin/32nm trench and 120nm depth for ~4:1 aspect ratio

1

2

4

5

3

Silicon fin

a-Si cap

Test Structure

Test Measurement

SIMS sees different cross sectional area of treated surface as the measurement travels down the structure

Conformality profile can be observed on the ensuing SIMS plot between points 2 and 4

N2 Plasma Nitridation on a 20Å ALD HfO2

Fin top width = 18nm Trench bottom width = 31nm Pitch = 66nm

Source: Applied Materials

Source: Applied Materials

1 2 3 4 5

Doping With N2 Plasma Shows Sidewall Drop-Off

Applied Materials Confidential

R 140

G 140

B 140

R 220

G 220

B 220

R 69

G 153

B 195

R 254

G 203

B 0

R 255

G 121

B 1

R 234

G 40

B 57

R 155

G 238

B 255

R 146

G 212

B 0

R 75

G 75

B 75

R 6

G 30

B 60

SILICON SYSTEMS GROUP

Plasma Chemistry Versatility OES Spectrum of NH3-Based Process

N2 Plasma is N2+ Ions; NH3 Plasma is NH Radicals

All Figures: AMAT data

Applied Materials Confidential

R 140

G 140

B 140

R 220

G 220

B 220

R 69

G 153

B 195

R 254

G 203

B 0

R 255

G 121

B 1

R 234

G 40

B 57

R 155

G 238

B 255

R 146

G 212

B 0

R 75

G 75

B 75

R 6

G 30

B 60

SILICON SYSTEMS GROUP SILICON SYSTEMS GROUP

TEM image of 13:1

conformality structure

Silicon trenches with 13:1 aspect ratio

SiO2 cap (etched in preclean)

amorphous-Si conformal fill

HfO2 not present in this image sample

3D SIMS Profile

Blanket XPS N% = 10%

NH3 Plasma Nitridation Provides Much Better Conformal Doping Than N2

Nitridation 3D Conformality – HfO2

All Figures: AMAT data

NH3 Plasma

NH3 RTP

N2 Plasma

Applied Materials Confidential

R 140

G 140

B 140

R 220

G 220

B 220

R 69

G 153

B 195

R 254

G 203

B 0

R 255

G 121

B 1

R 234

G 40

B 57

R 155

G 238

B 255

R 146

G 212

B 0

R 75

G 75

B 75

R 6

G 30

B 60

SILICON SYSTEMS GROUP

Remote Plasma N2 RTP

Features

Ion-free high density radicals at

high temperature (500-1200°C)

Fully conformal

Conformal nitride growth on silicon

and treatment of nitride films

Applied Materials Confidential

R 140

G 140

B 140

R 220

G 220

B 220

R 69

G 153

B 195

R 254

G 203

B 0

R 255

G 121

B 1

R 234

G 40

B 57

R 155

G 238

B 255

R 146

G 212

B 0

R 75

G 75

B 75

R 6

G 30

B 60

SILICON SYSTEMS GROUP SILICON SYSTEMS GROUP

3D Nitridation Conformality

17

Remote Plasma N2 Nitridation Shows Equivalent Conformality to Thermal NH3

RT-NH3

Remote

Plasma

N2

N2 Plasma

10:1 Si Trench Structures

Applied Internal Data

TEM image of 13:1

conformality structure

All Figures: AMAT data

Applied Materials Confidential

R 140

G 140

B 140

R 220

G 220

B 220

R 69

G 153

B 195

R 254

G 203

B 0

R 255

G 121

B 1

R 234

G 40

B 57

R 155

G 238

B 255

R 146

G 212

B 0

R 75

G 75

B 75

R 6

G 30

B 60

SILICON SYSTEMS GROUP SILICON SYSTEMS GROUP

Remote Plasma RTP – Treatment of Nitride

Remote Plasma RTP Improves Properties of Deposited Nitride Films

RPS

RPS

RPS = Remote Plasma Source

All Figures: AMAT data

Applied Materials Confidential

R 140

G 140

B 140

R 220

G 220

B 220

R 69

G 153

B 195

R 254

G 203

B 0

R 255

G 121

B 1

R 234

G 40

B 57

R 155

G 238

B 255

R 146

G 212

B 0

R 75

G 75

B 75

R 6

G 30

B 60

SILICON SYSTEMS GROUP SILICON SYSTEMS GROUP

Concluding Summary

Growing adoption of ALD conformal thin films

– Poorer film quality than conventional high temperature CVD films

Film treatments enabled with ICP inductively coupled plasma

– Improved film quality including leakage, wet etch rate

Conformal ion-assisted film treatments possible up to 10:1 aspect ratio

– Plasma oxidation of SiO2 and plasma nitridation of Si3N4

Conformal nitridation of HfO2 enabled by NH3 plasma nitridation

– Tunable ion/radical density and energy with ICP plasma

Remote Plasma RTP enables additional conformality

– Ion-free for conformal high aspect ratio treatments