Atomic Layer Deposition

The Business of Science®

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© Oxford Instruments Plasma Technology Ltd, 2009. All rights reserved.

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FlexAL and OpAL are trademarks of Oxford Instruments Plasma Technology Ltd.Ref: OIPT/ALD/2009/01

FlexAL® and OpALTM

References

1. Deposition of TiN and HfO2 in a commercial 200 mm remote plasma atomic layer deposition reactor. S.B.S. Heil, J.L. van Hemmen, C.J.Hodson, N. Singh, J.H. Klootwijk, F. Roozeboom, M.C.M. van de Sanden and W.M.M. Kessels, J. Vac. Sci. Technol. A, 1357, (2007).

2. Plasma and thermal ALD of Al2O3 in a commercial 200 mm ALD reactor J.L. van Hemmen, S.B.S. Heil, J.H. Klootwijk, F. Roozeboom, C.J.Hodson, M.C.M. van de Sanden and W.M.M. Kessels, J. Electrochem. Soc. 154, G165 (2007).

3. Plasma-assisted atomic layer deposition of Al2O3 moisture permeation barriers on polymers . E. Langereis, M. Creatore, S.B.S. Heil,M.C.M. van de Sanden, and W.M.M. Kessels, Appl. Phys. Lett. 89, 081915 (2006).

4. Surface passivation of high-efficiency silicon solar cells by atomic-layer-deposited Al2O3. J. Schmidt, A. Merkle, R. Brendel, B. Hoex,M.C.M. van de Sanden and W.M.M. Kessels, Prog. Photovolt: Res. Appl. (2008)

5. Remote Plasma Atomic Layer Deposition of Hafnium Oxide, Hyeongtag Jeon, AVS 5th International Conference on Atomic LayerDeposition 2005.

6. Reaction mechanisms during plasma-assisted atomic layer deposition of metal oxides: A case study for Al2O3. S.B.S. Heil, J.L. vanHemmen, M.C.M. van de Sanden and W.M.M. Kessels, J. Appl. Phys. 103 (2008) 103302

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Introduction to ALD FlexAL® and OpALTM

Atomic Layer Deposition (ALD) offers the opportunity tocreate precisely controlled ultra-thin films for advancedapplications on nanometre and sub-nanometre scales,with conformal coating into high aspect ratio structures.

Oxford Instruments’ ALD product family offers a uniquenew range of flexibility and capability in the engineeringof nanoscale structures and devices by combining remoteplasma ALD processes with thermal ALD.

A family of tools to meet your needsThe ALD product family encompasses a range of tools tomeet the varied demands of academia, corporate R&D andsmall scale production.

FlexAL tooln Remote plasma & thermal ALD in one flexible tooln Automated 200mm load lock for process flexibilityn Clusterable for vacuum transfer of substratesn Cassette to cassette handling increases throughput

suitable for production

OpAL tooln Open loaded thermal ALD tool with plasma option

n Field upgrade available for plasma option

n Small wafer pieces up to full 200mm wafers – equallysuitable for academic and industry R&D

FlexAL and OpAL precursor deliveryn Multiple liquid or solid precursor delivery systemsn Vapour draw or bubbling up to 200ºC source temperaturen Rapid gas deliveryn Extracted precursor enclosures with attachable glove box

for use during precursor changeover

Self limiting digital growth Remote plasma and thermal ALD in one flexible tool

Exploit the benefits of plasma ALDThe remote plasma option allows for the widest possiblechoice of precursor chemistry with enhanced film quality:

n Plasma enables low-temperature ALD processes and the remote source maintains low plasma damage5

n Effective metal chemistry through use of hydrogenplasma rather than complex thermal precursors

n Eliminates the need for water as a precursor, reducingpurge times between ALD cycles

n Higher quality films through improved removal ofimpurities, leading to lower resistivity, higher density, etc.

n Ability to control stoichiometry

n Plasma surface treatment

n Plasma cleaning of chamber is possible for somematerials

OpAL tool

A. TMA chemisorbtion B. TMA purge C. O2 plasma D. Short post plasma purge

ALD cycle for Al2O3 deposited using TMA and O2 plasma6. Only step C varies between H2O for the thermal process or O2 plasma.

Example applications of ALDn Nano-electronics

n High-k gate oxides1

n Storage capacitor dielectrics2

n High aspect ratio diffusion barriers for Cuinterconnects

n Pinhole-free passivation layers for OLEDsand polymers3

n Passivation of crystal silicon solar cells4

n Highly conformal coatings for microfluidicand MEMS applications

n Coating of nanoporous structures

n Bio MEMS

n Fuel cells

Power ahead with intuitive softwareEasy to use, multi-user level, PC2000TM cross platformcontrol software is tailored for rapid cycle ALD.

Be reassured with global customer supportLocal engineers based worldwide.

Save time with process guaranteesDeveloped in our applications laboratory and backed byon-site process acceptance and support.

Purge time for thermal ALD of Al2O3 (H2O) andremote plasma ALD of Al2O3 (O2). Data courtesyof Eindhoven University of Technology

FlexAL tool

Plasma Etch & Deposition Atomic Layer Deposition Ion Beam Etch & Deposition Nanoscale Growth Systems HVPE

Process Library ALD Process Benefits

Conformal, controlled, low pin-hole nano-scale growth

Rapidly populating the periodic table

Oxford Instruments has an extensive process library, and newprocesses are continually developed.

Material Metal precursorNon metal precursors*

O2 H2O N2 H2 NH3

Al2O3 TMA P T

AlN TMA P1 P1 P2, T

Cu Cu(acac) T P

HfN TEMAH P P T

HfO2 TEMAH P T

LaAlO La(thd)3 / TMA P

La2O3 La(thd)3 P

Pt Me3Pt(MeCp) T P

Ru Ru(EtCp)2 T P

SiN Not disclosed P1 P1 P2

SiO2 BTBAS P

SiON BTBAS P P

Ta2O5 TBTDET P T

TaN TBTDET P P

TiN TiCl4 P P

TiO2 TTIP P

W WF6 P

WN WF6 P P

ZnO DEZ T

Process developmentn The list of developed processes is

continually expanding; please contactyour OIPT sales representative for thelatest information

n Alternative chemistries may also beavailable for certain materials

n Oxford Instruments provides on-goingprocess support to its customers offeringadvice on developing new materials andcontinued access to our latest ALDprocess developments

General ALD process benefitsn Excellent process control with wafer to wafer

repeatability <±1%

n Up to 200mm wafer with typical uniformity <±2%

n Excellent step coverage even inside high aspectratio structures

n Virtually pin-hole free films

n Low film impurities; particularly with plasma ALD

n Growth at room temperature 25ºC possible withplasma ALD

Specific material properties by ALDn High k

n High breakdown voltage

n Low resistivity for conductive nitride and metal filmsby plasma ALD

n Superb thin film barrier properties

Excellent repeatability dueto linear self-limitinggrowth. Example shownof Al2O3 by plasma ALDmeasured by in-situspectroscopic ellipsometryat depositiontemperatures down toroom temperature (25ºC).

Data courtesy ofEindhoven University ofTechnology 2

High breakdown voltage2

of Al2O3 and highdielectric constant1 ofHfO2. HfAlO can providean average k value, buthigh breakdown voltage.

HfO2 from TEMAH and O2

plasma – Auger analysisshowing low carboncontent of <2% obtainedby FlexAL remote plasmaALD

Chlorine impurities of TiNby RBS and resistivity byFPP deposited at 350°C.Resistivity <200µΩcmpossible with plasma ALDeven at low temperatures.(350ºC plasma = 550ºCthermal)

Al2O3 barrier deposition atroom temperature. Graphshows excellent singlelayer moisture and oxygendiffusion barrier(20 nm Al2O3 with WVTR = 5.0·10-3 g·m-2·day-1)

Data courtesy ofEindhoven University ofTechnology 4

Parameter Al2O3 HfO2

Dielectricconstant

8 18

Breakdownvoltage

~9MV/cm

~3MV/cm

* P = plasma gases used (P1, P2, indicates alternative gases)T = thermal gases or vapours used (T1, T2 indicates alternative chemistries)

Plasma ALD of 80 nm Al2O3 from TMA and O2 plasma in a 10:1 aspectratio deep trench capacitor structure.

Courtesy of Eindhoven University of Technology and Philips Research

Global applications supportAs a global company, processes developed in the UK Applications Laboratory and withcollaboration partners are delivered tocustomers via local front-line support. Oxford Instruments’ network of processsupport engineers is based in the USA, Asiaand Europe.

Plasma Etch & Deposition Atomic Layer Deposition Ion Beam Etch & Deposition Nanoscale Growth Systems HVPE

Overview of Product Range System Features

Flexible, configurable, powerful tools

Both FlexAL and OpAL can be fitted with the Oxford Instruments Plasma Technology remote InductivelyCoupled Plasma (ICP) ALD source. This source is close coupled to an OIPT matching unit with dedicated controlsystems to enable rapid plasma striking.

OpAL pneumatic chamber openingThe OpAL system chamber is raised by means of a twobutton pneumatic hoist. A nitrogen purged glove box can surround the chamber for dry loading of samples, givinglower oxygen contamination in nitride and metal films.

FlexAL wafer handling optionsn Single wafer loadlock

n Square handler clustered to other process modules, e.g. PlasmalabSystem400 sputter deposition

n Hex handler with robot and 25 wafer cassette for 4”, 6”or 8” wafers (no tools required to swap between wafers)

n All configurations can be located entirely within thecleanroom or through-the-wall

Designed for safe handling ofhazardous precursorsn Precursors are housed inside of extracted stainless

steel enclosures with nitrogen purge

n FlexAL precursor modules (opposite, left) are supplied with a glove box

n OpAL precursor cabinet (opposite, right) is supplied with a glove panel

FlexAL schematicPowerful PC2000 software

Feature OpAL FlexAL

SubstratesUp to 200mm wafers and pieces directly on stage

Up to 200mm wafers handlingand pieces on carrier plate

Bubbled liquid and solid precursors Up to 3 Up to 4

Max precursor source temperature 200ºC (jacket) 200ºC (oven and jacket)

Water delivery (inc source pot) Standard Recommended option

Mfc controlled gas lines with rapid delivery system;1) thermal gas precursors (e.g. NH3, O2)2) plasma gases (e.g. O2, N2, H2)

2 internally.Up to 8 in externally

mounted gas pod

Up to 10 in externallymounted gas pod

Plasma Option / field upgrade Option

Loading Open load Loadlock or cassette

Ellipsometry ports Yes Yes

Swagelok 10ms rapid pulsing ALD valves Yes Yes

Removable liners for cleaning Yes Yes

PC2000 rapid control software Yes Yes

Clusterable to other process modules NoYes - including third party MESC

modules as special option

Wafer stage temperature range 25ºC – 400ºC 25ºC – 400ºC (550ºC option)

Safe and reliable tools

Integrated in-situ diagnostics6

Both FlexAL and OpAL are compatible with in situdiagnostics such as J.A. Woollam* ellipsometers, massspectrometers or RGA’s (SRS, MKS*, Hiden), optical emission spectroscopy.

*These instruments can be controlled via the PC2000 software.

Plasma Etch & Deposition Atomic Layer Deposition Ion Beam Etch & Deposition Nanoscale Growth Systems HVPE