D4C Overlay runs on any fab server cluster using the ... And full-wafer dedicated chuck overlay (DCO) ..... Our dedicate
ASML’s customer magazine | 2014
A faster route to better overlay Product lifecycle management: added-value across the industry Focus on a new star
6 4
10 A faster route to better overlay
images | Colofon
16 © 2014, ASML Holding BV ASML, ASM Lithography, TWINSCAN, PAS 5500,
6
EUV shows consistent performance
Editorial Board
PAS 5000, SA 5200, ATHENA, QUASAR, IRIS, ILIAS,
in the field
Lucas van Grinsven, Peter Jenkins
FOCAL, Micralign, Micrascan, 3DAlign, 2DStitching, 3DMetrology, Brion Technologies, LithoServer,
10 Product lifecycle management: added-value across the industry
Managing Editor
LithoGuide, Scattering Bars, LithoCruiser, Tachyon
Michael Pullen
2.0, Tachyon RDI, Tachyon LMC, Tachyon OPC+, LithoCool, AGILE, ImageTuner, EFESE, Feature Scan,
12 New nodes with your installed TWINSCAN NXTs
Contributing Editor
T-ReCS and the ASML logo are trademarks of ASML
Saskia Boeije
Holding N.V. or of affiliate companies. The trademarks may be used either alone or in combination with
16 Focus on a new star
Contributing Writers
a further product designation. Starlith, AERIAL,
Paul Tuffy, Jan-Willem van der Horst,
and AERIAL II are trademarks of Carl Zeiss. TEL is
Thomas van Wezel, Jules Tops,
a trademark of Tokyo Electron Limited. Sun, Sun
Janneke van Heteren, Remi Pieternella,
Microsystems, the Sun Logo, iForce, Solaris, and the
Stuart Young
Java logo are trademarks or registered trademarks of Sun Microsystems, Inc. in the United States and other
Circulation
countries. Bayon is a trademark of Kureha Chemical
Karen Lo, Michael Pullen, Saskia Boeije
Industry Co. Ltd. Nothing in this publication is intended to make representations with regard to whether any
For more information, please see:
trademark is registered or to suggest that any sign
www.asml.com/images
other than those mentioned should not be considered to be a trademark of ASML or of any third party. ASML lithography systems are Class 1 laser products.
2
ASML Images, 2014
Editor’s note
30 years down, 30 plus to go By Michael Pullen, Senior Communications Specialist
As 2014 comes to a close and we look
You will hear how ASML’s new Design
Last, but not least, you will read about
back on our 30 year history of providing
for Control (D4C) Overlay software
the latest YieldStar system, the 250D.
lithography solutions for the ever growing
is tackling the current industry
It is the first metrology system capable
and changing semiconductor industry,
requirements for overlay, focus control
of measuring overlay, focus and CD
it is amazing to see the challenges
and critical dimension uniformity (CDU)
in a production environment, helping
that we have overcome, and the
and will meet the future demands by
customers maximize their yields of good
accomplishments that we have made,
allowing customers to design and
wafers-per-day.
together as an industry. As we look to
optimize metrology targets that can be
coming years, there are obvious hurdles
used to deliver significant improvements
I hope you find this issue informative
and roadblocks that we must overcome
to overlay performance.
and of value. Please feel free to
to continue down the path set forth by Moore’s Law.
provide direct feedback to me at Another hurdle you will read about is
[email protected] so that we
the cost ineffectiveness of transitioning
can continue to improve the magazine
In this issue of Images Magazine,
from node to node and how ASML’s
and your experience.
we will take a look at how we, at ASML,
System Node Extension Packages
are preparing to clear those hurdles and
(SNEPs) are breaking through this by
Happy reading!
continue down the path for another
converting any TWINSCAN NXT system
Mike
30 plus years.
to a newer model in the field, effectively extending its capabilities another one or
Going back nearly to our start in 1984,
two production nodes.
the PAS 2500/5000 is still in use today at several customers. While its End
As you may have read recently, our EUV
of Service is approaching, the Mature
tools are meeting and exceeding the 500
Products Service team is redefining
wafer per day barrier, with one machine
the life cycle of all ASML products and
at IBM exposing 637 EUV wafers in a
mapping out four major lifecycle stages
single day! Additional advancements
that will increase transparency with
and improvements are being made to
customers and help them improve their
source power, availability and particle
own business planning in the future.
contamination.
3
A faster route to better overlay By Paul Tuffy, Product Manager BRION Wafer Fab Applications
Abstract | ASML’s new Design for Control
Fast, precise and accurate, ASML’s
the target design for a strong diffraction
Overlay software identifies the best
YieldStar diffraction-based metrology tool
signal. Moreover, the increased use of
metrology target design for any given layer
has made it possible to continually monitor
opaque materials in the latest technology
combination and process in the shortest
on-product overlay performance and
process stacks – such as the sacrificial
time. It allows customers to design and
provide faster feedback to the scanner.
layers used in spacer processes – make
optimize metrology targets that deliver
This is done through a feedback loop
target optimization for signal strength
the ideal balance of printability, detectability,
where overlay data from an in-track
doubly important.
accuracy and device matching. These targets
YieldStar module is converted into
can be used in an automated feedback
smart exposure corrections by system
loop to deliver significant improvements to
enhancement packages like Litho Insight.
on-product overlay performance.
These corrections are fed back to the scanner for subsequent wafers, resulting in improved on-product overlay performance.
Identify the best target designs in the shortest time
These overlay measurements are based on grating targets included in the reticle designs for the many overlay-sensitive
Design for Control
layer combinations in a product. The design
ASML’s new Design for Control Overlay
of these targets needs to fulfill certain
(D4C Overlay) software package helps
performance requirements. It must print
semiconductor manufacturers identify
well across the process window, and
the best metrology target designs in the
deliver an easily detectable diffraction
shortest time. It does this by simulating
signal to ensure precision and short
the lithography process and resulting
measurement times. It also needs to
YieldStar measurements of candidate
help ensure the measurements are
targets including the full layer stack,
accurate and not affected by variability
allowing the design parameters of the
in processing steps such as etching and
target for a given layer to be optimized.
chemical mechanical planarization (CMP). D4C Overlay transforms target
4
As design features shrink, more and more
optimization from a lengthy trial-and-
overlay targets are needed to capture
error process to a quick and reliable
the overlay fingerprint at the required
computational one. It avoids the need
level of detail. At the same time, placing
to carry out repeated wafer experiments
targets within the actual device becomes
on different test designs – significantly
advantageous as it allows more accurate
speeding up process development.
and higher-order corrections. This in-die
And it allows users to try out thousands
placement is only feasible with very small
more targets and fully explore the design
targets, making it important to optimize
space – enabling the development of
ASML Images, 2014 the final target design in a single reticle tape out cycle.
Design for Control Overlay optimizes YieldStar overlay targets for best on-product overlay performance
By identifying targets that balance
Printability
precision and accuracy, D4C Overlay
Detectability
• Mask optimization • Litho process window • Design rule compatibility
helps deliver significantly better onproduct overlay performance. What’s more, it can match the aberration
• Target selection to meet TMU/ MAM requirements • Including process variations for detectability robustness
D4C
sensitivity of the target to that of the critical device features being printed in
Accuracy: Device matching
the specified layer, enabling further
device
target
overlay gains. (See Fig. 1)
• Improved overlay due to improved aberration sensitivity matching (target to device)
Accuracy: Process robustness
∆SWA
• Target selection for robust and accurate overlay with lowest sensitivity to process induced asymmetry
Tailor-made targets Design for Control Overlay is a complete target optimization software package.
Fig. 1
Its easy-to-use graphical user interface guides the user through the target design process step by step. This includes a flexible interface for defining the process stack in the same way as it is built in the fab: adding etch, deposition, CMP and patterning steps to build each layer. This approach allows almost any stack design to be simulated. (See Fig. 2) Once the user has specified the process design rules and constraints, the software runs an initial simulation to identify target candidates that meet the printability and detectability specifications.
Fig. 2
The detectability, overlay accuracy and lens aberration performance of
D4C Overlay Target Design Flow
these candidates are then tested in a further round of simulations. An extensive set of built-in analysis features
Input
YieldStar detectability
Detectability robustness
Design input
(process flow)
Simulate detectability KPIs @ nominal
Simulate detectability robustness KPIs
Simultation settings
Filter out targets with poor detectability and printability
including 2D heat maps and 3D amplitudes simplifies the selection of optimal targets. Once the user has chosen a number of best
(YS & target patterns)
candidates for experimental validation, the D4C Overlay software outputs the
Litho model
complete reticle pattern for that layer in
(Tachyon FEM+)
the GDS format. (See Fig. 3) In-house design and optimization
Optional
Litho Printability Simulate printability KPIs
Overlay robustness
Target selection
Simulate overlay robustness KPIs
Select targets based on weighed KPIs
Aberration matching Simulate aberration sensitivity KPIs
Fig. 3
D4C Overlay runs on any fab server cluster using the Tachyon Flex platform.
target printability and detectability.
Together these systems deliver a
We offer extensive training and detailed
The full version including overlay
holistic solution to the current industry
user manuals on how to get the best
accuracy was launched in Q3 2014.
requirements for 5 nm overlay,
from the package. This allows companies
It is designed for use with ASML’s
60 nm focus control and 1.6 nm CDU
to keep target design and optimization
TWINSCAN NXT immersion ArF and
(after etch). Planned enhancements to
completely in house.
NXE extreme ultraviolet scanners in
all these products will support roadmaps
conjunction with YieldStar YS 200C or
towards 2017 that demand 2.5 nm overlay,
D4C Overlay was initially released in
YS 250D metrology tools and Litho Insight
50 nm focus control and 1.1 nm CDU
late 2013 in a version that focused on
overlay optimization software.
(after etch). 5
EUV shows consistent performance in the field By Jan-Willem van der Horst, Product Manager EUV
Abstract | ASML has qualified and shipped
EUV lithography is making continued
Excellence as standard
six TWINSCAN NXE:3300B extreme
progress towards maturity and production
These installed systems demonstrate
ultraviolet (EUV) lithography scanners.
insertion. Systems at customer sites are
that the NXE:3300B’s excellent imaging
With multiple systems exposing wafers
delivering consistent performance fit for
performance is repeated across multiple
at customer sites, the NXE:3300B
development of 10 nm logic and sub-20 nm
systems. In fact, the systems in the field
is demonstrating consistently good
DRAM products. Productivity levels are
often achieve performance levels in excess
performance. Meanwhile, enhancements
up – leading to a record number of EUV
of specifications – for example printing
to source power and availability are driving
wafer exposures in a day.
16 nm dense lines with large process
productivity gains. In addition, a joint
windows. Full wafer focus uniformity
research program with customers and
The TWINSCAN NXE:3300B is our
better than 12 nm is common, as is critical
materials suppliers is exploring a pellicle
third-generation EUV lithography system,
dimension uniformity (CDU) below 1.5 nm.
concept to protect EUV masks from
with a resolution specification of 22 nm.
particle contamination, and hence reduce
Six of these systems have been qualified at
printed defect levels.
our facility in Veldhoven, the Netherlands and shipped to customer sites. A further five are currently going through the qualification process.
6
Excellent imaging performance is repeated across multiple systems
ASML Images, 2014
X - axis Y - axis
Matched machine overlay [nm]
6
Systems feature the new MOPA-PP source
Lot (3.2,3.0)
4.5
configuration running
3
at 40 W
1.5 0
Overlay performance too is consistently
1
2
3
4
5
6
7
8
excellent. The six installed systems exhibit
Wafer – after std modelling
matched machine overlay (MMO) with
corrected using standard scanner model
our immersion scanners of around 5 nm or better. And full-wafer dedicated chuck overlay (DCO) below 1.4 nm has been
Fig. 1: MMO performance for various machines
achieved. (See Fig. 1) Customers had already shown that the
Logic 10nm Metal 1 layer: Wide Depth of Focus at 20 mJ/cm2
NXE:3300B is capable of printing real devices structures for the 10-nm logic node with an extended depth of focus (DoF). Now by combining the scanner’s off-axis illumination (OAI) capabilities
FOCUS: DoF 120nm
Quasar illumination¬ Dose ~20 mJ/cm2¬NXE OPC+ -80nm -60nm -40nm -20nm 0nm 20nm 40nm 60nm 80nm NXE:3300B, 10 nm logic Metal 1 layer, 45 nm pitch.
Clips courtesy of STMicroelectronics
with ASML-Brion’s advanced optical proximity correction (OPC), they have reproduced those results at much lower doses. For example, customers have printed 10-nm logic metal 1 layers with a 120 nm DoF at a dose of around 20 mJ/cm2 – both figures are within requirements for high-volume production. (See Fig. 2) Pushing up productivity The six installed NXE:3300B systems feature the new master oscillator
Fig. 2: 10-nm logic metal 1 layer
power amplifier pre-pulse (MOPA-PP) 7
In-situ collector cleaning¬
Effectiveness of product configuration confirmed
Field collector cleaned in NXE:3300 source vessel test rig
Start
End
Reflectivity,%
Reflectivity Al-05 (unpolarized) 55 50 45 40 35 30 25 20 15 10 5 0 50
100
150
200
After cleaning Brand new
250
300
350
Substrate radius, mm
Reflectivity restored within 0.8% of original Cleaning in off-line MOPA Prepulse development vessel
Start
End
Off-line cleaning using NXE:3300B source vessel with product configuration hardware
Fig. 3
Full-size EUV pellicle prototype manufactured
Pellicle Absorber pattern
Pellicle transmission requirement: 90% Current status: ~86%
Fig. 4
8
Mask
µm-size particles do not affect imaging
ASML Images, 2014
source configuration running at 40 W.
working with customers and materials
Complementing this increased source
suppliers in an ongoing joint research
power, we have developed a number of
program to explore pellicles for protecting
features to improve source availability.
EUV masks from particle contamination. Together these efforts aim to improve
Among these is a system for cleaning the
printed defect levels. (See Fig. 4)
collector mirror in-situ. The system can restore the collector’s reflectivity to almost
EUV lithography requires reflective rather
brand new, eliminating the need to take
than transmission masks. Hence pellicle
the system off line to replace the collector.
materials for EUV have higher single-pass
We’ve also shown that the source can be
transmission requirements than for DUV
run in a fully automated mode with good
lithography, as the EUV light must pass
dose control. This increases availability
through the pellicle twice. The year-long
while maintaining a 99.9% die yield.
research collaboration has developed a
(See Fig. 3)
new higher-transmission pellicle. Tests on half-size pellicles mounted on the reticle
As a result, productivity from our
have shown the new pellicle concept
EUV scanners has been steadily rising –
has little or no impact on CD or line
resulting in the recent announcement by
roughness. The pellicles have also shown
IBM of a new 1-day EUV wafer exposure
good robustness, surviving multiple
world record. In a test of the source,
exposures and extensive mechanical
they exposed 637 EUV wafers in a single
testing – including unusually rough
day. This test to verify the source’s power
handling – intact.
“Thank you for participating in our reader survey. We appreciate your input as it helps us improve the magazine. The Bose® SoundLink Mini Speaker is won by Sang Nyung Yoon of DuPont Electronics”
output and reliability was carried out with the scanner linked to a track, and using an exposure dose of 20 mJ/cm2 and conventional illumination. “The test was designed to check if the newly installed source was working
First full-size, free-standing pellicle prototype for EUV masks
correctly. Exposing so many wafers was an unexpected bonus – due to the source operating so well,” Dan Corliss, IBM’s EUV
The first full-size, free-standing pellicle
development program manager.
prototypes for EUV masks have been manufactured. Exposure tests using these
In the meantime, several customers have
prototypes are planned for later this year.
cleared the 500 wafers per day barrier. These achievements show we are on track
Enabling future shrink
to meet our previously stated end-of-year
Single-exposure EUV lithography enables
goal of 500 wafers per day as an average
aggressive feature shrink to drive the
and our 2016 goal of 1500 wafers per day
semiconductor industry forward over the
to support volume production.
coming years. The imaging performance reported from our NXE:3300B systems
Addressing the mask defect challenge
already exceeds requirements for the
With EUV lithography scanners becoming
10-nm 2D logic node. And ASML’s
more mature, ASML is also active in
technology roadmap extends the NXE
addressing ancillary issues related to
platform to beyond the 7 nm node. As the
EUV lithography wafer fabrication.
next step on that roadmap, integration
One example is mask front-side
and qualification of our fourth-generation
defectivity. In parallel to improving the
system – the TWINSCAN NXE:3350B –
system’s overall cleanliness, we are
has already begun.
www.asml.com/ImagesSurvey
9
Product lifecycle management: added-value across the industry By Thomas van Wezel, MPS Product Manager Product Life Cycle
Abstract | ASML is introducing a more
ASML is 30 years old this year.
This involves clearly defining the various
formalized approach to product lifestyle
In celebrating this anniversary, it is
stages of a product’s lifestyle and how
management. This involves mapping our
remarkable to note that one of the very
ASML supports machines in each of
systems to four major lifecycle stages
first machine types we developed is still
these stages. Then by communicating
defined by the level of support ASML offers.
in service today. Almost 30 years old
this information along with the relevant
Timelines for when each system type
itself, the PAS 2500/5000 is still being
timelines, including target dates for stage
transitions between stages are defined well
used in production at several customers.
transitions, we hope to create greater
in advance, and reviewed annually based on
Of course its role has changed: from the
transparency for both our customers and
market demands and customer feedback.
cutting edge of semiconductor production
our suppliers on exactly what they can
By communicating this information in a
to More-than-Moore applications.
expect from ASML. This will in turn help
timely fashion, we will increase transparency
simplify business planning.
for customers and suppliers – helping them
However, all good things come to an end.
improve their own business planning.
And the PAS 2500/5000 will soon become
Defining the lifecycle
the first ASML scanner to officially come
To start this process, we have divided
to its End of Service (EoS), with ASML
the product lifecycle into four stages
no longer providing support. With this
based on the level of service we offer.
milestone approaching, ASML is also
We call these stages Regular Service,
launching a more formalized approach
Extended Service, Limited Service and
to product lifecycle management.
End of Service.
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ASML Images, 2014 based on business potential and customer feedback on a yearly basis. New
Benefits throughout the chain Refurbishment
7 years
Product lifecycle management is
Extended Service
Limited Service
End of Service
Economic lifetime extension for ASML and customer
Controlled Exit (typically 3 years)
Possible Transfer to 3rd party
Regular Service
something we have always done within ASML. But by formalizing it in this way, we believe we can bring benefits for everyone. For example, by considering the lifecycle stages and end of life issues more rigorously in our design process,
time
we can help extend the productive life of new systems. Fig. 1: Product lifestyle stages
Meanwhile, by communicating the transitions between lifecycle stages,
Easier for customers and suppliers to plan their business
we make it easier for customers and suppliers to plan their business and investment in equipment. Our aim is to share these timelines as early as possible
In the Regular Service stage we provide
for all types. Although the transition to
– particularly for the transition from
our highest level of support for new
Extended Service is always seven years
Extended to Limited service and from
and recently refurbished machines to
after manufacturing stops, some system
Limited service to End of Service – and
maximize system availability and enhance
types may be manufactured for longer
at least one year ahead of the transition.
performance. We offer full availability
than others. This could depend on the
This will give everyone time to factor the
of parts and a range of service level
system’s popularity and intended role.
information into their business decisions.
options to suit different semiconductor
For example, a pre-production system like
manufacturers’ needs.
the TWINSCAN NXE:3100 would come out
Hence customers will be aware just how
of manufacturing earlier than a production
long ASML will be supporting the systems
Around seven years after we finish
workhorse like the TWINSCAN XT:1900i.
installed at their facility, and can decide
manufacturing a machine type, it will
Similarly, customer demand for and usage
the best time to migrate to new tools
transition to the Extended Service stage.
of refurbished systems plays a role in
based on the service available, resale
Here again, we offer full parts availability
deciding when a system type transitions
potential, etc. If they are considering
and a range of service level options.
to Limited Service or EoS.
buying a remarketed ASML system,
But now the focus is more on extending the economic lifetime of systems.
they will be able to confirm how long the Hence, a key part of our product lifecycle
system will be supported before they
approach is deciding well in advance when
finalize the deal.
At some point after that, the system type
each system type will transition between
moves into the Limited Service stage
stages and communicating that in a timely
Suppliers will be better able to predict
where we start to ramp down the support
fashion to both customers and suppliers.
the demand for their products as they
we offer. Spare part availability isn’t guaranteed and service is supplied on a best effort basis. Finally, the system type moves to End
will know ahead of time when we will
Extend the productive life of new systems
of Service, where ASML stops providing
be manufacturing, refurbishing and supplying spare parts for each system type. This allows them to plan capacity, staffing levels and equipment requirements with more confidence.
support altogether. However, systems may continue to provide an economically
Of course, these timelines aren’t
Given the long lifetimes of our systems,
viable production facility – typically in
something that we dictate and set in
this long-term planning of the entire
niche applications – and we will endeavor
stone. Transition dates are reviewed
lifecycle will bring value for all parties
to help customers find alternative service
based on feedback from customers and
involved in the semiconductor industry
solutions where possible. (See Fig. 1)
suppliers. For example, we have already
and associated businesses.
decided to prolong the PAS 5500’s Communicating timelines
Extended Service period by four years
Details of product lifecycle stages and
The timeline for when a system type
to 2022. We will continue to review and
transition timelines are available via
moves from stage to stage is not the same
update our product lifecycle timelines
ASML’s Account Managers. 11
New nodes with your TWINSCAN NXTs By Jules Tops, SNEP Project Cluster Manager DUV, and Janneke van Heteren, SNEP Product Marketing Manager
Abstract | ASML’s System Node Extension Packages (SNEPs) allow any TWINSCAN NXT system to be converted into a newer model in the field. For example, the SNEP:A2C and SNEP:B2C respectively transform NXT:1950i and NXT:1960Bi systems into an NXT:1970Ci. SNEPs allow semiconductor manufacturers to extend their installed NXT systems for volume production at new nodes. This helps them transition from node to node in a cost effective manner, always having the latest lithography system while managing their capital expenditure.
12
ASML Images, 2014
installed Everyone likes getting value for their
its capabilities by one or two production
money. And at ASML, we want to make
nodes. The transformed system meets the
sure we deliver the maximum value for
full ATP specification for the new model,
our customers. That’s why our TWINSCAN
and comes complete with a standard
scanners have always been built using
ASML warranty running from the date
a highly modular architecture that allows
of the upgrade. In effect, manufacturers
systems to be upgraded in the field with
gain all the benefits of buying a brand
new options to improve productivity and
new system, without the hassle of
performance. This allows semiconductor
de-commissioning an installed tool.
manufacturers to buy new systems in configurations tailored to their needs
Our SNEP strategy gives semiconductor
at that time, safe in the knowledge
manufacturers the maximum flexibility in
that the tool can be adapted as their
planning their investment in lithography
needs change.
equipment. You can buy an NXT system
Any installed NXT system can be converted to a newer model in the field Now with the TWINSCAN NXT platform,
for high-volume manufacturing at one
we are taking that approach a step
node and then upgrade it when you are
further. Through System Node Extension
ready to transition to the next node.
Packages (SNEPs), any installed NXT
This avoids the need to invest in brand
system can effectively be converted to
new systems each time you move to a
a newer model in the field – extending
new production node.
13
A completely new system
immersion hood. Where necessary,
Following this learning period, the first SNEP
Two SNEPs are available: the SNEP:A2C
the projection lens may also be replaced
upgrade projects at customer sites were
and SNEP:B2C. These transform
with a newer model.
carried out earlier this year. These systems
NXT:1950i and NXT:1960Bi systems
are now operating in production and in spec,
respectively into our latest scanner,
Once all the necessary hardware and
allowing the customers to move into volume
the NXT:1970Ci. This represents a
software is upgraded, the team qualifies
production at a new node.
one-node extension for the NXT:1960Bi and
all the modules and then the system
a two-node extension for the NXT:1950i.
as whole before carrying out the ATP
An ongoing roadmap for value
(See Fig. 1)
specification. The final system has all
The SNEP:A2C and SNEP:B2C are just
the features and performance of a
the first steps in our roadmap for node
straight-from-the-factory NXT:1970Ci
extension. As each new TWINSCAN NXT
(see box), backed up by our standard
system is released, we will also be making
12-month new system warranty.
available packages for transforming installed
Extending its capabilities by one or two production nodes
NXT systems into the very latest model. A flexible process
In this way, we aim to give semiconductor
Our dedicated SNEP team has already
manufacturers the ability to transition from
carried out a number of system upgrades
node to node in the most cost-effective way
at ASML facilities around the world.
possible – ensuring they always have the
Upgrades are carried out by a dedicated
This has allowed us to optimize the
capabilities needed for profitable volume
SNEP team, in cooperation with our
upgrade procedure to maximize flexibility
manufacturing of advanced products as
local customer support personnel.
and minimize downtime. For example,
well as the freedom to control their capital
Each upgrade is tailored to a specific
by performing jobs in parallel wherever
expenditure and investment in new equipment.
tool via the tool number. The exact
possible, we reduce the time taken for
sub-systems to be upgraded are
the upgrade. This also affords us some
determined based on the system’s
freedom in the order in which tasks are
current configuration. But typically the
carried out to reduce the impact of any
upgrade includes replacing the wafer
unexpected delays. Moreover, the team
handler, stage and table, and installing
is able to adjust the upgrade process
the new ultra-violet level sensor (UV-LS),
according to the space available around the
parallel ILIAS (PARIS) sensor and CO2
system, reducing risk.
B2C path A2C path NXT:1970Ci
Performance
Snep = System Node Extension Package NXT:1960Bi 1951 lens
NXT:1960Bi 1952 lens
NXT:1950i + PEP NXT:1950i 1950/1951 lens 1950/1951 lens
Node N
SNEP: A2C (+ 2 nodes)
Node N+1
Node N+2
Fig. 1: SNEP is a System Node Extension Package: New hardware and software installed during a field transformation will bring the NXT:1950i or NXT:1960Bi to the newest node. (NXT:1970Ci specs)
14
NXT:1960Bi systems into an NXT:1970Ci
TWINSCAN NXT:1970Ci specifications
NXT configurations in the field and transformation paths
SNEP:B2C (+1 node)
Transform NXT:1950i and
Full-wafer dedicated chuck overlay
2.0 nm
Full-wafer matched machine overlay
3.5 nm
Full-wafer focus uniformity
20 nm
Full-wafer CDU (isolated features)
1.3 nm
Full-field throughput (96 shots)
250 wph
Defects
< 7 per wafer
ASML Images, 2014
The TWINSCAN NXT:1970Ci By Remi Pieternella, Senior Product Manager
The latest model in our TWINSCAN NXT
Latest data on the NXT:1970Ci’s focus,
overlay and defectivity performance, showing consistently within spec
Matched Machine Overlay Single Machine Overlay
immersion lithography platform, the NXT:1970Ci targets profitable
5
Overlay performance [nm]
high-throughput, high-precision ArF
4,5
volume production at the 1x nodes.
4 3,5
Compared to previous systems,
3
the NXT:1970Ci includes a new
2,5 2
multifunction parallel ILIAS (PARIS)
1,5
sensor for measuring the effects of
1
lens and reticle heating. Together with
0,5
a multi-sector wafer table heater,
0
Systems
this enables better overlay performance. In addition, a brand-new ultraviolet level sensor (UV-LS) improves focus control and reduces process dependency during leveling. A new high bandwidth wafer stage enables faster wafer exchange for
Latest data on the progression of the NXT:1970Ci’s availability and reliability performance
thermal control to improve overlay and
25,0
Overlay performance [nm]
higher throughput, and features enhanced imaging performance. Meanwhile, a new immersion hood with a carbon dioxide
20,0
“gas knife” reduces defect levels and
15,0
allows scan speeds up to 800 mm/s.
10,0
Around fifty NXT:1970Ci systems have been shipped to customers and are
5,0
operating within specifications. A number of these systems are being used in
0,0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36
Systems
high-volume production, where they are exposing over 4000 wafers per day (averaged over a week). The average availability for these systems is around 95%, and mean time between failures continues to rise thanks to continuous software improvements.
15
Focus on a new star By Stuart Young, Product Manager YieldStar
16
ASML Images, 2014
Abstract | ASML has shipped several of its new YieldStar 250D systems.
First metrology system capable of measuring overlay,
This next-generation metrology tool targets
focus and CD in a production environment
the 10-nm logic and 1X-nm memory nodes. It is the first metrology system capable of performing simultaneous on-product overlay, focus and CD measurements
ASML has launched the latest member
Together with ASML’s Design for Control
at a speed and quality that allows
of its YieldStar diffraction-based
(D4C) metrology targets (see page 4),
real-time feedback for scanner control.
metrology family. The YieldStar 250D
this enabled a significant step forward
This helps semiconductor manufacturers
is a next-generation metrology tool,
in accuracy, precision and speed for
maximize their yields of good wafers-
targeting production at the 10-nm logic
FEOL, MOL and BEOL layers compared
per-day. A roadmap of software-only
and 1X-nm memory nodes. It offers even
to traditional image-based overlay (IBO)
system enhancement packages will deliver
better accuracy and precision than its
metrology systems. (See Fig. 1)
continued in-the-field enhancements to the
predecessors, and reduces the time taken
new system’s performance and capabilities.
for an individual measurement by around
YieldStar systems are available in
30%. This allows customers to measure
two configurations that are identical
overlay, focus and CD on product wafers
in design: a traditional standalone tool
– while maintaining the same high wafer
and system integrated into the wafer
throughput as their TWINSCAN scanner.
track. The integrated systems use less fab space and reduce lithography
Building on a solid platform
cluster cycle time as the metrology can
The new system builds on the success
be carried out in the lithography cluster
of previous YieldStar family members.
without overhead. They also allow real-
YieldStar was the first metrology system
time metrology feedback to the scanner.
to deliver small-target diffraction-based
Hence for scanners with the right options
overlay (µDBO) measurements.
installed, data from each lot can be
Y-overlay
y = 0.9178x - 0.8156 R2 = 0.9393
Device overlay measured by CD-SEM after etch
Yieldstar µDBO measurement ADI
Yieldstar µDBO measurement ADI
X-overlay
y = 0.9452x - 0.1708 R2 = 0.969
Device overlay measured by CD-SEM after etch
Fig. 1: Yieldstar DBO overlay measurements show excellent correlation to real device overlay
17
used to control the scanner and
YieldStar 200C has been replaced with
the YieldStar 250D means users can
optimize exposure for subsequent lots.
a new source that delivers substantially
now also measure on-product imaging
This improves both individual scanner
more light and improved illumination
performance – specifically focus and CD.
performance and machine matching.
characteristics. Secondly, the optical path
This makes the YieldStar 250D the first
from source to wafer has been improved
metrology system capable of measuring
These unique capabilities have seen
to increase transmission and extend the
overlay, focus and CD in a production
YieldStar become the metrology tool
range of transmitted wavelengths.
environment.
(HVM) fabs around the world.
The more powerful source and improved
YieldStar’s unique diffraction based-
Following on from a very successful
transmission increase the total amount of
focus (DBF) measurement directly and
year in 2013, we expect the number
light at the wafer level by up to 50 times.
accurately measures on-product focus
of installed systems to double in 2014.
As a result, the specified move-acquire-
across the entire process window. Just as
Over that time, shipments of integrated
measure (MAM) time is just 0.35 seconds
for overlay, YieldStar focus measurements
systems have grown rapidly as more
(compared to 0.5 seconds for the
can be used as the basis for calculating
manufacturers have seen the value of
YieldStar 200C). Hence the YieldStar 250D
and applying real-time corrections via
real-time, data-based scanner control,
is capable of 1200-1600 measurements
ASML’s Imaging Optimizer scanner option.
and have now become around half of the
per lot at the full production throughput of
For focus critical features, these exposure
total number of YieldStar shipments.
ASML’s latest TWINSCAN NXT scanners.
corrections have demonstrated on-product
Tests on product wafers from logic and
CDU improvements of around 15%.
memory customers have shown that
(See Fig. 4)
of choice in high-volume manufacturing
On-product CDU improvements of around 15%
the YieldStar 250D is consistently over 30% faster than the YieldStar 200C.
The YieldStar 250D also supports CD
Improvements are even more pronounced
measurements as an option.
for more challenging layers – with gains
CD measurement capabilities have
above 80% in some cases. (See Fig. 3)
been extended, with a particular emphasis on reducing the time required to create
Supporting advanced chip structures
recipes. This allows semiconductor
The installed YieldStar systems have
Meanwhile, the extended wavelength
manufacturers to measure overlay,
proven to be excellent performers
range allows the new system to support
focus and CD simultaneously with
in fabs. They have, for example,
3D chip features such as FINFETs and
no loss of productivity.
helped semiconductor manufacturers
3D-NAND structures. These structures
successfully match on-product
require thicker process stacks leading
Facing the future
overlay across their installed base of
to lower light transmission which makes
The YieldStar 250D is part of ASML’s
scanners. YieldStar systems have also
metrology more challenging. The YieldStar
ongoing holistic lithography roadmap,
demonstrated impressive reliability,
250D uses sensing wavelengths up to
with future systems planned to keep
with availability above 99% and 13-week
780 nm to increase transmission through
metrology performance on pace with
mean time between interrupt (MTBI)
the stack. Hence, it can deliver fast,
scanner capabilities. Just like our
figures of over 1000 hours. (See Fig. 2)
accurate metrology on FINFET devices
scanner platforms, this roadmap is built
at the 10 nm logic node as well as
on a philosophy of continuous system
3D-NAND structures.
enhancement. All installed YieldStar 200C
Shedding more light on metrology The YieldStar 250D is based on the
systems can be fully upgraded to the new
same fundamental platform as its
More focus on focus
YieldStar 250D in the field. Several field
successful predecessor the YieldStar
Prior to the YieldStar 250D, scanner control
upgrades have already been successfully
200C. But it takes the YieldStar benefits
based on metrology feedback focused
performed, and customer demand for
to the next level by dramatically
on optimizing on-product overlay
such upgrades remains strong. When the
increasing the amount of light reaching
performance. Of course, overlay isn’t
time comes the YieldStar 250D will be
the wafer. It does this in two ways.
the only performance metric that affects
field-upgradeable to subsequent models.
First, the xenon arc lamp used in the
wafer yield. The increased speed of
18
ASML Images, 2014
Improvements aren’t limited to just
MTBI of Yieldstar machines
developing new systems. Our YieldStar roadmap also includes regular,
Median Reliability
1400
packages to extend the capabilities and
1200
economic lifetime of installed systems.
1000 800
significant usability improvements for
600
MTBI [hours]
These packages allow us to make both R&D engineers and HVM users, and to introduce new functionality. Furthermore, these enhancement
400 200 0
packages are used to deliver increased sampling, accuracy and precision
201314 201316 201318 201320 201322 201324 201326 201328 201330 201332 201334 201336 201338 201340 201342 201344 201346 201348 201350 201352 201402 201404 201406 201408 201410 201412 201414 201416 201418 201420 201422 201424 201426 201428 201430 201432
software-only system enhancement
performance. In this way, we help ensure that all customers have the latest
Fig. 2
metrology capabilities available in a timely and robust fashion.
200C MAM 250D MAM
1 0,9 0,8 0,7 0,6 0,5 0,4 0,3 0,2 0,1 0 14nm 14nm 14nm 14nm 14nm 16nm 16nm 16nm 16nm 16nm 16nm 16nm 16nm 16nm 16nm 16nm 16nm 16nm 10nm 10nm 10nm 10nm 10nm 10nm 10nm 10nm 10nm D1x D2x D2x D2x D2x D2x D2x D2x D2x D2x 14nm 14nm 14nm
Move-Acquire-Measure time [sec]
MAM time data
Node
Fig. 3: The 250D delivers more than 30% increase in sampling
Uncorrected focus uniformity
Measured focus uniformity with focus offset & tilt corrections applied shows 20% improvements
Simulated improvement with 1) focus offset correction 2) focus offset and tilt correction
21.5
20.2
20.4
21.2
20.8
21.2
21.2
20.9
15
21
20
20.2
25 Focus 3σ (nm)
22.0 19.8
10
1
2
3
4
5 6 Slot #
7
8
9
Ave
10 5
5 0
30
25.7
25.7 22.2 20.2
25.6 23.2 20.7
26.9 23.3 21.0
24.1 20.2 18.0
25.1
26.3
26.2 21.8 19.5
15
22.0 19.2
20
21.4 19.6
Focus 3σ (nm)
25
Focus Uniformity (interfield) 3σ (nm)
Interfield Focus 3σ (nm) Simulated Z per field correction potential 3σ (nm) Interfield Focus 3σ (nm)
30
2
4
6
7 8 Slot #
9
10
Ave
0
Fig. 4: Yieldstar on product focus measurement together with Imaging Optimizer delivers 20% on-product focus uniformity improvement
19
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