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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.

  1. What is dynamic cooling?
  2. What is static cooling?
  3. What makes point-of-use Dynamic?
  4. Why is dynamic temperature control important?
  5. Why is temperature stability of the etch process important?
  6. What is the difference between main etch temperature drift and wafer to wafer temperature stability?
  7. Can POU improve delta temperature on the wafer or “within wafer” uniformity?
  8. Why is POU more reliable than a compressor?
  9. Why Does a compressor based unit consume more power than a POU system?
  10. Why does POU cost more than a compressor- based unit?
  11. What do IDM’s generally say about the cost of installing, maintaining and operating compressor-based systems?
  12. What is the service life of a POU unit?
  13. What do I do when a system fails?
  14. 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?

  1. What is dynamic cooling?

    1. 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.
    2. 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.
  2. What is static cooling?

    1. 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.
  3. What makes point-of-use Dynamic?

    1. 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)

  4. Why is dynamic temperature control important?

    1. 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.
    2. The ability to manipulate temperature for various stages of the process enables process flexibility and eliminates temperature-induced CD variability.
    3. There is also evidence of increases in yield due to temperature stability.
  5. Why is temperature stability of the etch process important?

    1. 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.
  6. What is the difference between main etch temperature drift and wafer to wafer temperature stability?

    1. 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.
  7. Can POU improve delta temperature on the wafer or “within wafer” uniformity?

    1. 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.
    2. 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.
  8. Why is POU more reliable than a compressor?

    1. 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.
    2. 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.
    3. Compressor-based systems have large internal volumes, frequent leaks and oversized unreliable pumps, all of which require substantial routine maintenance.
  9. Why Does a compressor based unit consume more power than a POU system?

    1. 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.
    2. 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.
  10. Why does POU cost more than a compressor- based unit?

    1. 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.
  11. What do IDM’s generally say about the cost of installing, maintaining and operating compressor-based systems?

    1. 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.
    2. 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.
    3. 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
  12. What is the service life of a POU unit?

    1. The standard warranty is one (1) year and the current MTBF is approximately 4 years.
  13. What do I do when a system fails?

    1. 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
  14. 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?

    1. 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.
 
Offering a Complete Range of Thermoelectric Temperature
Control Systems, Including Dynamic Point-of-Use Chillers
for Semiconductor Wafer Processing Equipment.
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