brief aml presentation

AML – Wafer Bonding Machines & Services

AML Equipment & Services overview


Who is who in AML(Main contacts)

Rob Santilli - Managing Director ( & Founder)

Tony Rogers - Technical Director ( & Founder)

David Adamson - Manufacturing ( & Founder)

Vince Wilson - Sales & Business Development

Manager

Nick Aitken - Applications Engineer

Sue Pepler - Administration


• Company founded 1992

• MEMS Design, Manufacture & Process Development background

• Founders made first in-situ aligner-wafer bonder in 1985

• AML focus on & Provide Wafer Bonding equipment & Wafer bonding

services (BONDCENTRE)

•Worldwide installed base of machines

AML- Company History

From MEMS background not Mask Aligner for IC


Basic features of AML bonders


Schematic of Unique in-situ Activation, Alignment & Bond

T <560 C

HV <2500V

•Heat + Pump + Align

•Independent platen T

•Flexible

•2 to 8 inch wafers2 to 8 inch wafers

•Fast cycles timesFast cycles times


AML Wafer Bonders

• Anodic Bonding Si-Glass• Direct Bonding e.g. Si-Si• Glass Frit Bonding• Eutectic Bonding• Thermo-compression• Adhesive Bonding• Aligned Embossing

In bond chamber alignment & bonding

in one machine = higher throughput

Wafer bonding capabilities:-


AML Advantages One System Does it ALL (Align, Activate and Bond in one bond chamber)

ALIGN / BOND• No wafer movement between alignment & bonding – guaranteed

alignment accuracy• Simultaneous alignment, heating and vac pump-down (fastest cycle

time) • In-bond chamber alignment at bond temperature (reduces expansion

misalignment effects you would see with competitors jigging) • No flags touching bond surfaces so no possibility of contamination,

damage or flag removal issues• Best system for vacuum encapsulation (Large gap between wafers

during pump-down)• Independent control of upper & Lower wafer temperatures –

(useful for getter activation)• Best system for reducing / forming gas environment - e.g. for

eutectic bonding. (reproducible wafer surface environment)• Wide range of processes possible – Including Nano-Imprint


ACTIVATE (enables low temperature Direct Bonding) • In-bond chamber RAD activation option – activated surfaces cannot be re-contaminated

• Less surface roughening and more uniform activation than plasma

• No exposure of wafers to energetic ions --> can be used with sensitive device wafers

• Wider process time window for activation than with plasma- process time less critical

• In-situ system provides better reproducibility and therefore better process stability

AML Advantages


AML AdvantagesECONOMIC• Lowest cost per bond & ownership

• No mask aligner required- free to choose best mask aligner for your ‘mask aligning’

• System is complete – no other equipment required

• Reasonably priced spares

EASY• Very high reliability – minimal servicing – fast & simple to maintain

• Standard machines as well as custom options to suit specific customer needs

• Easy to use - system up and running and in use in minimum time

SUPPORT• Excellent process support via BONDCENTRE – fast response

• More than 20 years machine & wafer bonding process experience.

• Worldwide Machine base.


AML tooling solutions for Direct Bonding

• Ideally Si-Si bond is self propagating- minimises

stress/bow in the resulting assembly

• The AML spring pin / edge clamp tool allows control

of self bond propagation rate and bond initiation point


Bonding ToolWafer bow system

• The displacement and force exerted in bowing the upper wafer is tuned with respect to the stiffness of both wafers.

• The profile and force distribution of the lower pin chuck can be tuned to give the required profile in the bonded assembly – flat or reduced stress.

Variable force and displacement

lower chuck


Example Bond

IR transmission image of void free Si – Si direct bond. 100mm wafers.Bond performed on AML402 direct bonder - using pin chuck system


New system features, now and planned


New Processes on AML Wafer Bonders

• Hot Embossing – Characterisation has just started

New Developments on AML Wafer Bonders• Inclusion of RAD in-situ surface activation for low temperature bonding (available for new orders) see page after next

• Addition of Pattern recognition software

• Inter-pixel measurement for sub-micron alignment accuracy

• Upgrading of manipulators from manual to stepper motor control

• Motorised Z Drive

Development pipeline:- System Automation


Outline Specification

Force up to 5000N Stroke up to 750 microns

T up to 500 C (cooling) up to 6” wafers

Operation in Vacuum 2 micron alignment between stamp & substrate

New Polymer Micro Hot Embossing & Nano Print tool

• Applications: e.g. Bio-sensors & Microfluidic devices

• Polymers: SU8, PDMS, PMMA..

• Tool fits AML bonder platform or stand alone machine


Basic Bonding Methodsoffered:

• Anodic• Direct (Fusion)• Low Temperature (activated) Direct• Thermocompression• Eutectic• Glass Frit• Adhesive


AML AWB04 Aligner Bonder


Anodic Bonding

• Graphite upper platen (reduced voids and no back surface stains)

• Current limited bonding (enables bonding to thick insulating layers and reduces stress variation across the bonded wafers, and reduces risk of electrical breakdown)

• Aligned triple stack (sequential & Simultaneous process)


Direct Bonding

• In-situ Radical activation enables unique “Activate, align & bond” capability

• In-situ activation provides controlled environment for process development and bond interface reproducibility

• In-situ activation also enables removal of hydrocarbon contamination


Schematic of Unique in-situ Activation, Alignment & Bond

T <560 C

HV <2500V

•Heat + Pump + Align

•Independent platen T

•Flexible

•2 to 8 inch wafers2 to 8 inch wafers

•Fast cycles timesFast cycles times


Radical Activation Tool

Experimental set-up using glass vacuum chamber – showing electrical discharge confined between the ring electrodes


IR transmission Image150mm RAD activated

bond

Void free in situ activated bond – annealed at 200C for 1 hr


Radical-Co-axial Source

Sou

rce

Sou

rce

DC source

R. pump

Gas supply

Only radicals in this region

Wafers for in-situ activation

Earthed screen


Radical Activation Tool

Electron Density (discharge ring) 2.5 x 10 16 m-3

Ion flux very low in the centre

Measurement show that there is no plasma

in the centre zone. All that remains that could affect

the wafers surfaces is radicals and UV radiation

Electron Density less than 5 x 10 13 m-3 in the centre (wafer activation region)


Radical Activation

Spectra of untreated and treated silicon

0

1000

2000

3000

4000

5000

6000

02004006008001000

Binding energy /eV

Co

un

ts p

er s

eco

nd

Centre

Spectra of untreated and treated silicon

0

1000

2000

3000

4000

5000

6000

02004006008001000

Binding energy /eV

Co

un

ts p

er s

eco

nd

Untreated

XPS spectra showing comparison of silicon wafer before and after activation by Oxygen Radicals

Shows reduced carbon peak post exposure


Some Radical Activation Results

0.00

0.50

1.00

1.50

2.00

2.50

3.00

0.000 5.000 10.000 15.000 20.000 25.000

Exposure Time /min

Bo

nd

str

en

gth

/J.m

-2

radicals

O2 plasma

Comparison of Radical vs Plasma Activation Bond Strength for Various Activation Exposure Times (strength measured using Razor Blade Method)


Some Radical Activation Benefits

Produces less roughening of the surface than plasma activation

Uniform activation (no edge effects as typically seen for plasmas)

Wider process time window for activation

In situ process eliminates variation in activation strength with time

No exposure of wafers to energetic ions

Bond can be heated / contacted at bonding temperature = significant advantage for dis-similar substrates or “hard to bond” substrates


Uniform Force Bonding

Platen / support structure designed to give uniform force across the platen area

Use of graphite inserts further improves the force uniformity

Uniform force is needed for the following bonding processes

Glass FritEutecticThermocompressionAdhesive


Improvements in Force Uniformity

The above images were obtained using pressure sensitive film. The black areas are full scale, white areas are zero load.

Old Bonders New Bonders


Some Customer ReferencesCustomer Details

Laboratory for Electro-Optics Systems (LEOS)Bangalore, India

Louisiana State UniversityBaton Rouge, USA

Sumitomo Precision Products Co. Ltd.Japan

Fraunhofer InstituteIZM Berlin, Germany

Korea Photonics Technology Institute (KOPTI)Guangju, Korea

CNRS-LAASFrance

Xiamen UniversityChina

Fraunhofer InstituteHalle, Germany

Semefab LtdUK

Tyndall InstituteCork, Ireland


BONDCENTRE

Wafer Bonding Services


Why BONDCENTRE?• There is a business in bonding wafers for people!• The penetration of Wafer Bonding into many new areas

outside MEMS, warrants special attention & resources to satisfy the wide range of bonding process requirements. Good opportunity!

• The more processes that are developed the more reasons there are to buy AML machines.

• Niche – no one else is doing this!


Strengths

• Very strong MEMS design & process background – especially with respect to Wafer Bonding

• Relevant customer base• Strong network of partners built up over many years • Equipment supplier – transfer the process onto a machine• Selected by UK government to be best to provide the

service


BONDCENTRE SERVICES OFFERED

• Wafer Bonding Process Development e.g. for many novel materials; silicon, glass, sapphire, strained silicon, InP, GaAs,…

• Wafer Bonding process selection & design for your application

• Commercial Wafer Bonding Service prototype to production

• Wafer Bonding Technology Transfer (inc Equipment) & Training

• Associated Processes (Pre & Post Bond)

• Applications knowledge for:

MEMS Smart cut layer transfer Advanced Substrates Wafer Level Packaging 3D integration Vacuum EncapsulationTemporary Bonding LEDs


Associated Pre & Post Bond Services:

• Wafer Cleaning & Activation • Wafer Characterisation e.g. Profiling & Surface

Roughness• Wafer Structuring: e.g. Channels, Holes &

Conducting Vias• Wafer Processing: e.g. Deposition, Electroplating• Wafer Preparation: Thin to required Thickness &

Surface Finish - Planarisation (CMP)• Inspection of bonded assemblies - SAM & IR


• WAFER ALIGNER BONDERS 4 machines in Class 10• METROLOGY; AFM, Ra, PROFILE, TTV• MEGASONIC WAFER CLEANING • NEW ‘RAD’ ACTIVATION• INSPECTION: ACOUSTIC MICROSCOPE (SAM) & IR• ELECTROPLATING • SCREEN PRINT - GLASS FRIT/ADHESIVE• POWDER BLASTING E.G. GLASS MACHINING • WAFER THINNING • CMP

• Also access via long term collaboration with CMF @ Rutherford to:• PHOTOLITHOGRAPHY DEPOSITION- PVD & CVD & FURNACES• ETCHING – DRY & WET• WAFER SAW WIRE & BUMP BONDING• METROLOGY: THIN FILM, LINE WIDTH, SEM

Equipment Set Available:Equipment Set Available:


4 Aligner –Bonders in class 10


SAM – Scanning Acoustic Microscope


Many thanks!

brief aml presentation

Documents

aml focus

situ alignerwafer bonder

installed base of machines

mems background

mems design

situ activation

alignment bond t