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Frequently Asked Questions
| Below you will find answers to the most frequently
asked questions. If you cannot find your answer
here, please feel free to Contact
Us.
- What is dynamic cooling?
- What is static cooling?
- What makes point-of-use Dynamic?
- Why is dynamic temperature
control important?
- Why is temperature stability
of the etch process important?
- What is the difference between
main etch temperature drift and wafer to wafer temperature
stability?
- Can POU improve delta temperature
on the wafer or “within wafer” uniformity?
- Why is POU more reliable
than a compressor?
- Why Does a compressor based
unit consume more power than a POU system?
- Why does POU cost more than
a compressor- based unit?
- What do IDM’s generally
say about the cost of installing, maintaining and
operating compressor-based systems?
- What is the service life
of a POU unit?
- What do I do when a system
fails?
- Can I do the installation
with my own technicians or do I need to pay for
a Noah factory team to install and start the system?
- What
is dynamic cooling?
- Dynamic
Temperature Control Systems are capable
of rapid changes in temperature to correspond
to changes in wafer processing temperatures.
With dynamic systems, the temperature of the
fluid supplied to the chamber is managed to
compensate for changing processing conditions,
so the temperature of the wafer chuck can
be maintained in a narrow range.
- These systems have the ability to sense chamber
temperature drifts and compensate faster and
more precisely than a conventional (remotely
located) static compressor-based systems.
- What
is static cooling?
- A typical compressor-based or static cooling
system receives a temperature set-point from
the host tool. The system maintains this temperature
set-point in its resevoir by cycling the compressor
and heater on and off. The fluid is pumped to
the chamber at the set-point temperature from
its remote location. Heat losses between the
unit and chamber are substantial and vary from
installation to installation. As a result, wafer
chuck temperatures will fluctuate because the
static system is only capable of maintaining
a constant temperature in its reservoir.
- What
makes point-of-use Dynamic?
-
True Dynamic Temperature Control can only
be achieved when all five (5) of the following
system design and installation requirements
are met:
- fluid set-point temperature is controlled
at the return loop
- very small fluid reservoir and process
fluid-loop volume (< 1 US GA.)
- heating / cooling elements with rapid
ramp rates
- short hose lengths from the POU module
to the chamber
- maximized process fluid flow rate
(Therefore, installing a static unit next
to a chamber will not enable it to provide
dynamic temperature control)
- Why
is dynamic temperature control important?
- Dynamic
Temperature Control maintains temperature
set-point in real time. This allows our customers
the opportunity to optimize each process step
with tailored temperature set-points.
- The ability to manipulate temperature for
various stages of the process enables process
flexibility and eliminates temperature-induced
CD variability.
- There is also evidence of increases in yield
due to temperature stability.
- Why
is temperature stability of the etch process important?
- Etch is a chemical process and temperature
is a catalyst that impacts the etch process.
With stable temperature on the wafer, we have
stable etch profiles and better control of polymer
build-up. As temperature changes, the rate of
etch can change outside the desired process
specifications.
- What
is the difference between main etch temperature
drift and wafer to wafer temperature stability?
- Both main etch temperature drift and wafer
to wafer temperature drift are not desirable
and can result in an unacceptable temperature-induced
profile. Temperature drift within a batch of
1, 10 or 30 “boats” describes wafer-to-wafer
drift.
- Can
POU improve delta temperature on the wafer or “within
wafer” uniformity?
- Delta temperature change on the wafer is a
characteristic of the chuck. Every chuck has
an inherent temperature distribution across
the surface that is unique to its design.
- The temperature distribution across the wafer
reflects the temperature distribution of the
chuck. For example, the edge temperature may
differ from the center temperature. POU will
not eliminate this problem but will maintain
temperature within the design parameters of
the chuck.
- Why
is POU more reliable than a compressor?
- The Noah POU has one moving part: a magnetically-coupled
pump. This seal-less pump minimizes the risk
of leaks, and is designed for continuous operation
for the service life of the POU module, which
is more than 4 years.
- POU also incorporates solid-state Peltier
devices, which provide both heating and cooling
capacity to the system. These devices have no
moving parts and temperature control is achieved
electrically without the use of greenhouse gases.
Consequently, Noah POU products are highly reliable,
environmentally desirable, costing the end-user
less to own and operate.
- Compressor-based systems have large internal
volumes, frequent leaks and oversized unreliable
pumps, all of which require substantial routine
maintenance.
- Why
Does a compressor based unit consume more power
than a POU system?
- Etch applications using Noah POU systems generally
operate at <20% of total system capacity,
and under these circumstances consumes
much less power when compared to a conventional
compressor-based system. The Noah POU utilizes
Peltier devices, which both heat and cool.
Since the heat pump capacity is directly controlled
by the applied power, energy consumption is
based on cooling or heating demand. By applying
power on demand, the POU system can also minimize
the load of the facility water system, and
saves the energy going into a cooling tower.
Oxide etch typically releases heat, and metal
etch consumes heat. Therefore, the Noah POU
is uniquely capable of active energy recycling
by heating and cooling with Peltier devices.
- Conventional chillers have oversized pumps
designed to manage ~6X more process fluid than
a Noah POU while being installed in the sub-fab.
These systems also incorporate compressors that
are always running regardless of the load. This
combination equates to an average power consumption
of >2.2kW, which is more than 50% higher
than a Noah POU system.
- Why
does POU cost more than a compressor- based unit?
- The initial purchase price of a Noah POU system
can be higher than a compressor system, however
the overall Cost-of-Ownership is always lower.
The Noah POU does not require costly PM’s,
requires fewer spares since it is more reliable,
consumes much less power, all while occupying
less space with the smallest footprint in the
industry.
- What
do IDM’s generally say about the cost of installing,
maintaining and operating compressor-based systems?
- Upon installation, conventional compressor-based
systems require 6-10 gallons of process fluid
per loop. The Noah POU system only requires
less than 1 gallon of process fluid, thus reducing
the overall (fluid) installation cost.
- Our customers demand lower Cost-of-Ownership.
They have a critical need to solve conventional
chiller reliability problems. These problems
include frequent leaks that lead to excessive
fluid consumption, frequent compressor maintence,
large footprint, short-lived deteriorating pumps,
and poor support by their chiller suppliers.
The mere size of a conventional chiller can
prohibit on-site service, support, and repair
without adversely affecting chamber up-time.
- Recently, a survey was conducted at several
leading IDM’s concerning the most important
attributes of a chiller/supplier. The top five
(5) results of that survey are:
1. Cost
2. Proven track record
3. Refurbish capability
4. Redesign capability
5. Energy Efficiency
- What
is the service life of a POU unit?
- The standard warranty is one (1) year and
the current MTBF is approximately 4 years.
- What
do I do when a system fails?
- Contact
Noah Precision, LLC and engage in the
Direct
Exchange Program for minimal chamber down
time. Additionally you can use these links
to help expedite the process:
– RMA Information
Page
– RMA Request
Form Page
– Contact
Us Page
- Can
I do the installation with my own technicians or
do I need to pay for a Noah factory team to install
and start the system?
- Noah offers start-up and/or turn-key installation
service with each system shipped. These services
also include ad-hoc system operational training
during the installation. However, the Noah POU
system is user-friendly and within the capability
of most users. Customers can also receive formal
training on-site, or at any Noah facility.
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