AML Machines Benefits AWB Main Benefits

The design of the AML-AWB benefits from over 20 years experience of Aligned - Wafer Bonding at AML.

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

ECONOMIC
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.

OTHER Technical benefits of the AML AWB Platform
In-situ alignment & bonding at temperature offers more reliable & accurate post bond alignment
Check alignment in bonding chamber & final adjust if necessary - fewer misalignments - Higher yield
AML can handle & bond thin silicon wafers
Very fast throughput - aligning simultaneous with heating & pumping down < 20-minute cycles
Can align with single side polished wafers
Current limited Anodic Bonding for better process control & device reproducibility
Versatile flexible platform e.g. NIL, Temp bonding, Chip bonding
Fast changeover between wafer sizes e.g. 5 minutes for 3" to 4"
Able to see bond formation via in-situ optics
Multi stack bonding facility
Customised bonding solutions by MEMS experts - Process feasibility (Application lab) to Machine!
Help to optimise WAFER BONDING PROCESSES as part of a MEMS Design
AML can cope with thicker assemblies, 8 mm

OTHER Commercial benefits of the AML AWB Platform
Easy to install, use, maintain, & service - minimal training.
Small footprint (lower running costs)
Does not take up time (operational or set up) on your mask aligner
System complete - We don't tie you into buying other equipment
AML made first Bonder 1985! Extensive machine & process experience.

This AML-AWB platform has the performance and throughput to satisfy most MEMS applications.

A feature of the Bonder is that alignment and bonding are performed in-situ in a high vacuum chamber. The wafers are loaded cold and heated in the process chamber. For high accuracy alignment (±2 microns or better), they are aligned and brought into contact after the process temperature is reached, thus avoiding differential thermal expansion effects which can compromise alignment.

This arrangement has an advantage over other bonders (where alignment is carried out outside the bonder) of enabling the user to make adjustments for any relative movement of the aligned wafers when brought into contact before finally committing to making the bond. This in-situ system also enables visual confirmation just before the bonding process that the desired alignment is still being achieved. This is particularly useful when the wafers are not absolutely flat

Key Functions

AWB PLATFORM - Outline SPECIFICATION

The AWB has the versatility to perform aligned: Adhesive, Anodic, Direct (High & Low Temperature) Eutectic, Glass frit, Solder & Thermo-compression bonding.

ALIGNMENT & BONDING IN ONE MACHINE

In-situ alignment 1 micron accuracy.
10-6mbar Vacuum to 2bar process gas
Voltage up to 2.5kV
Temperature up to 560° C
Forces up to 15kN
Market leading short bonding cycles / high throughput.
Cycle times for heating, vacuum, bonding & cooling down to 15mins

Automatic PC Control & Data acquisition
The machines are controlled via software in MANUAL or AUTOMATIC modes. All the bonding parameters e.g. current, voltage, integrated charge, temperature, chamber pressure, force, wafer separation, run parameters, recipes, wafer batch No for SPC and event logs are automatically stored in files & can be read in 'Note Pad' or MS EXCEL for graph plotting and trend analysis. Machines can also be networked.

Alignment:
In-situ alignment has advantages over other bonders (where alignment is made outside the bond chamber).

Alignment can be carried out hot or cold:
This eliminates alignment inaccuracies due to thermal expansion & mismatch between wafers, machine parts & platens A feature of the Bonder is that alignment and bonding are performed in-situ in a high vacuum chamber. The wafers are loaded cold and heated in the process chamber. For high accuracy alignment (2-5mm), they are only aligned & brought into contact after the process temperature is reached, thus avoiding differential thermal expansion effects which can compromise alignment.

Large wafer separation:
Allows large Temperature difference between wafers – ideal for getter activation or oxide reduction via process gas e.g. forming gas. Also allows fast, high vacuum & well defined bonding environment.

In-situ system:
Also enables visual confirmation just before the bonding process that the desired alignment is still being achieved. This is particularly useful when the wafers are not absolutely flat.

Wafer sizes:
2”, 3", 4", 5”, 6” & 8”. (Also chips & odd shaped substrates, but without alignment)

Manipulator:
Enables in-situ alignment of wafers under vacuum and at elevated temperature
Contact force: Up to 10kN provided by hydraulic actuation
Precise wafer parallelism adjustment
Alignment accuracy 2 µm

Optics:
Twin Microscope – camera system with through the- lens illumination. Two CCD cameras and side-by-side display of images. Including IR capability. Simultaneous display of wafer separation & bonding force for complete alignment control.

Bonding Environment:
Vacuum, or process gas. Fully automated dry turbo pumping system ~ 10-6 mBar to 2bar absolute pressure

Temperature:
Both Upper & Lower Platens independently adjustable in 1 °C steps. Heating & Cooling rates are programmable. Max Temperature is 560°C

Electrodes (for Anodic Bonding):
Full size heated platens for both upper and lower electrodes for better bond uniformity. 0-2.5 kV DC up to 40 mA. Constant current or voltageoperation, for improved process control & stress management.

Additional Options:
Triple stack bonding tool
Powered lid
Pressure control
Polymer Embossing Nano Imprint tool
High accuracy system for 1µm alignment

Platform Models:
AWB- 04 – 2” to 6” bonding
AWB- 08 – 6” & 8” bonding
AWE-07 – Polymer Micro Hot Embossing & Nano Print

Services Bondcentre

AML's BONDCENTRE provides a wealth of experience.
Services it offers are:

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)

AML provides a commercial, fast turn round, Wafer Bonding Service for 2", 3", 4", 6" & 8" wafers
Wafers cleaned and bonded in a class 10 clean room environment

Available In-situ Aligned Wafer Bonding Techniques:
Adhesive
Anodic
Direct (High & Low Temperature Unique RADICAL activation)
Eutectic
Glass Fit
Thermo-compression

Applications knowledge for:

MEMS LEDs
Advanced Substrates
3D integration, TSV (Through-Silicon-Vias)
Temporary Bonding
Vacuum Encapsulation
Wafer Level Packaging
Smart Cut - Layer Transfer