Lithography, patterning of the wafers, is a critical step
in the semiconductor process. Although conventional and even immersion
lithography generally do not require vacuum environments, extreme ultraviolet
(EUV) lithography and electron beam (e-beam) lithography do require vacuum
pumps. Edwards has you covered for both of these applications.
EUV Lithography Pumping Solutions
Multi-patterning techniques have their place, but the
future will likely require the use of EUV lithography due to the extremely short
wavelength of light EUV systems deliver. The vacuum environment is absolutely
critical for optimum performance of your system. Cleanliness of the vacuum
system is particularly important and helps to extend service intervals. We have
worked with EUV Lithography OEMs and light-source OEMs to develop precision
vacuum systems that deliver the maximum reliability for the large investment
E-Beam Lithography Solutions
E-beam lithography has an important role to play in
patterning of silicon wafers. Clean vacuum with low vibration is essential to
ensure precision and high up-time of your system.
Our Product Solutions
You will likely require a turbomolecular pump (TMP) to
deliver the ultra-high vacuum on your process tool. Our STP range of TMPs have
fully magnetically-levitated rotors to reduce the risk of contamination to the
chamber and extend service intervals. Today’s products have been developed to
reduce total costs and footprint through integration of the controller into the
pump itself, removing the need for an external controller and hefty control
cable between the controller and pump.
Chemical Vapour Deposition
Chemical vapour deposition (CVD) systems come in a
variety of configurations to deposit numerous types of films. The processes
also operate at different pressures and flow regimes, many using
fluorine-containing dry clean processes. All of these variables mean you will
want to consult with one of our application engineers to select the right pump
and gas abatement system to maximise our product’s service interval and
increase the up-time of your process.
Dry Pump Selection
CVD processes generally have four specific challenges to
overcome that will drive your dry pump product selection. These challenges are:
Many processes can generate
large amounts of powder by-product. The vacuum pump needs to be designed to
handle this powder without seizing. In some cases, the powder may actually be
sticky or require high temperature operation to ensure that other by-products
entrained in the powders do not condense inside the pump and jam the mechanism.
For nearly all powder-producing processes, you will be driven toward using a
pump employing a high-torque motor to be sure that the pump keeps rotating
Some of the
by-products of the semiconductor process contain gases that will change from
gas phase to solid phase as the partial pressure of the gas increases, or the
material comes in contact with cold surfaces. When pumping these by-products,
you will need a very hot pump and, preferably, a pump that has a uniform
temperature profile from inlet to outlet as much as possible.
Some processes will
require the pumping of halides. In particular, fluorine-containing cleaning
processes will be required to maintain the cleanliness of your chamber, but the
activated fluorine radicals can attack the internal surfaces of the pump. If the process is mostly using chemicals that
can corrode the pump, you will want to be sure that the pump temperature can be
set to a low value to reduce the risk of corrosion. Our pumps are designed with
selectable temperature set points and high rotational speeds to reduce the risk
of corrosion and reduce the overall rate of inevitable material loss that can
occur within the pump. For some CVD processes, a balance is struck with the
temperature set point to be sure that any condensation issues are avoided
without undue rates of corrosion.
Some of today’s
processes use metal-organic precursors that, as they pass through the chamber, can
result in by-products that have a high risk of depositing their metal contents
onto the pump surfaces. A low temperature pump is usually best to ensure long
service intervals for these applications.
Gas Abatement Selection
Every CVD process will require some form of gas abatement
device so that the toxic and dangerous by-products of the process can be safely
converted into disposable elements. We pride ourselves on our fuel-fired
exhaust gas management devices because of their ability to efficiently force
recombination of the by-products into safe compounds. Being fuel-fired with
multiple-inlet capability, you can get rapid deployment of Green Mode by
turning off the main burner when you do not need to abate your process exhaust.
Integrated Systems and Sub-Fab Solutions
With just a pump and a gas abatement device, you still
are not ready to run your process. You will need to connect the pump exhaust,
connect up your line heaters where required, run your water, purge and
electrical lines, and then get all of your control signals ready. You will also
have to consider double-enclosure, gas leak detection, and how you want to
conduct leak checks after your tool maintenance. All of these things will cost
you design time and money. We understand the problem so we have developed
integrated, process-specific solutions.
Our integrated systems are already pre-designed for most
semiconductor CVD processes. The exhaust heaters are set for the correct
temperature to minimize cost and maximise up-time. We put leak
check ports and gate valves where they are required. We can mount toxic gas
sensors within the unit and get the whole system enclosed and, most
importantly, you only need to provide one of each of the required utilities. We
distribute the purge, water, electricity, and control signals where they are
needed and create a ready-to-go system.
All of our integrated systems have been designed based on
global experience. We are leaders in vacuum and abatement, so we know what
works. We constantly innovate and improve what we do because you demand
excellence from Edwards.
With all of our equipment deployed in your fab, you will
want to know what’s going on all of the time. You want to know if any product
is in trouble or in need of maintenance. To answer this question, we offer our
FabWorks computer monitoring system.
The FabWorks system can use Ethernet connectivity to all
of our products to constantly retrieve status signals and store them in an
automated database. More than tracking trends in such parameters as input
power, current, temperature, or purge flow, you also can see warnings or alarms,
all of this data can be graphed and exported. With FabWorks you do not need to
be in the fab to monitor the equipment, once connected to your intranet, you
can be confident you have your finger on the pulse of the sub-fab.
For CVD processing, there will always be products that
become stressed and will need maintenance, in worst case scenarios, products
can suddenly fail. To prevent unwanted failures, we can work with you and
deploy our automated predictive diagnostics models. These models, matched to
your process, can provide warnings to you in advance of processing your next
batch of wafers so that you can maintain the pump or abatement device and
reduce the risk of stoppage mid-process.
Etch processes have become increasingly complex due to
the fine feature size of many semiconductors. Moreover, the proliferation of
MEMS devices and 3D structures has increased the use of silicon etch processes
for structures with high aspect ratio. Traditionally, etch processes could be
grouped into silicon, oxide, and metal categories. The lines between these
categories have become blurred with the use of more hard masks and high-k
materials being deployed in devices today. Some of the materials used in devices
today stubbornly resist vapourising during the etch process leading to
deposition within the vacuum components. Today’s processes really have become
more challenging than they were several years ago. We keep a close eye on
industry and process changes and maintain the pace of product innovation to
deliver class-leading performance.
Vacuum Pump Selection
Nearly every dry etch process will require a
turbomolecular pump (TMP) to deliver the low pressure you require for your
reactive ion etch (RIE) system. Edwards
invented the first TMP and we continue to challenge the industry with new
technology and performance. We offer a range of products to match your
application requirements. For example, for extremely low pressure, you can use
one of our all-bladed TMPs and marvel at the achieved compression ratios and
low base pressure. You can select a hybrid product that combines blades and
Holweck-designed rotors for high flow operation. We even have products tuned
for excellent hydrogen performance because, at molecular speeds, not all
molecules behave the same as they travel through the TMP.
We recognize that space is at a premium so for many of
our TMPs we have integrated the controller with the pump. Not only do you no
longer need to worry about routing of cumbersome control cables, you save on
rack space and spare pump management. We have also developed advanced heating
technology to reduce the risk of stubborn gases from sticking to the pump
internal surfaces. We have even pioneered new high-emissivity coatings for
really difficult applications that need high running temperatures.
For dry pumps, Edwards will help you select your product
to be sure that maximum up-time is achieved. Etch processes can be very
challenging to the pump because of the various gases used. For example, will
your process be mostly corrosive to the pump, likely to condense within the
pump, or neither of these? The process gases you use and the likely by-products
need to be considered carefully.
Gas Abatement Selection
Dry etch processes will require some form of gas
abatement to be sure you comply with your local emissions requirements. Moreover,
oxide etch, in particular, generates perfluorocarbon (PFC) emissions and you
want to be sure that your gas abatement can handle the flow rate of PFCs in
your process recipe. PFCs are a known contributor to global warming, so your
abatement strategy is important for all of us. Our inward-fired burners are
particularly adept at creating a hot flame that can break down the incoming
gases and reduce emissions of unwanted chemicals.
Physical Vapour Deposition
Physical vapour deposition (PVD) continues to be an
important process in semiconductor manufacturing. Liners and barriers continue
to make use of this well established semiconductor process.
If you are using a cluster tool, you will require a pump
for your load-lock chamber and also the transfer chamber. If your PVD tool
makes use of cryo pumps, you will also need to prepare a pump to regenerate your
cryo pump once it gets full. In many cases, the pump used for the transfer
chamber can also be used to regenerate your cryo pump. Many PVD tools used for
semiconductor processing deploy cryo pumps. However, increasingly,
turbomolecular pumps (TMPs) are used because the TMPs do not need maintenance
and they do not need regeneration. These two factors reduce your running costs.
Traditionally, gas abatement is not required for PVD
processes. However, if your PVD process tool also includes ALD or CVD chambers,
you will need process-ready vacuum pumps and gas abatement. Our application engineers
and product specialists will assist you in further information related to these
process types and help you determine the optimum size of pump for your system.
We can also make recommendations about pipe sizes to help you optimise your PVD
Today’s metrology tools represent years of advanced
development and continue to play a vital role to high yield and early detection
of process deviation. Clean, quiet vacuum is an important enabler to advanced
metrology tools. We provide a range of dry pumps and turbomolecular pumps (TMPs)
to match your vacuum environment conditions.
An example of our application of advanced technology is
our EPX range of dry pumps. These single-axis pumps rotate at high speeds and
can deliver final vacuum pressures up to three orders of magnitude lower than conventional
dry pump and booster combinations. In many cases, using one EPX pump can
eliminate the need for a TMP.
Another example of clean vacuum is our nXDS range of dry
scroll pumps. Edwards’ patented technology makes use of a precision engineered
bellows that guarantees that no grease from the bearings can ever outgas into
the vacuum space. Moreover, advances in tip seal engineering means significantly
extended service intervals.
Ion implant tools still have a significant role to play
in front end-of-line processing. The vacuum challenges associated with ion
implantation have not become easier with time and we recognise the challenges
of operating a vacuum pump in an electrically noisy environment. We are never
satisfied by testing for bare minimum conformance to established
electromagnetic immunity test standards. We know that pumps used on implant
tools will require greater immunity and special design features to be sure that
the high voltage sections of the implant tool do not interfere with pump
We also take particular care in the design of our
turbomolecular pumps (TMPs) to be sure that we can provide integrated heating
to high temperatures so that maximum reliability is achieved.
Our application engineers are will help you to select the
right products for your implant tool, whether those products are mounted on
your tool or beneath your tool in the sub-fab. We want to be sure you
experience the quality and reliability you demand from Edwards.
Diffusion / Epitaxy / ALD
Diffusion, epitaxy, and ALD processes are critical in the
manufacture of advanced semiconductor devices. Each of these applications, well
understood by Edwards, can represent challenges slightly different to normal
CVD processes. Diffusion furnaces will continue to be required as the industry
follows Moore’s Law and also if it diverges into More-than-Moore technologies.
In general, large capacity pumps are required to provide rapid chamber
evacuation, chamber environment exchange, and high throughput capability.
Epitaxial film deposition equipment continues to be
challenging. In many cases, very high flows of hydrogen at low chamber
pressures may be required. You will need a reliable pump with high hydrogen gas
throughput capability. More than this, you will want to take advantage of our
global application experience to be sure that you design your entire vacuum
system for safe operation. By-products of the epitaxy processes can be very
hazardous and will require special attention for safe operation.
Atomic Layer Deposition (ALD) processes are becoming more
common as device feature size decreases. Whether your system processes wafers
one wafer at a time, or in a batch, you will want to use our products that are
designed to minimise gas residence time and optimise pump thermal profiles and
purge locations to be sure you can achieve the longest service interval
possible. ALD processes can be rather challenging.
For all of the diffusion, epitaxy, and ALD processes, we are
able to give you the facts to help you select the right gas abatement device.
The materials you use in your processes and maximum flow rates will need to be
considered in configuring your abatement device.
Where appropriate an integrated system that incorporates
our global knowledge and best operating practice should be the preferred
solution. Our integrated systems provide excellent value and make managing your
process tools much easier via connection to our fab-wide monitoring systems.