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Headway Research, Inc.
Headway Research, Inc.

Spinner Systems

The model PWM32 Spin Controller has been upgraded and new product is now called model PWM50. We buy used equipment and factory re-furbish it at times, so the PWM32 may linger in our terminology and sales material for a considerable time. References to the PWM32 will be updated as soon as practical.

See the special page explaining the main differences in the two models.

(except PS80 Manual Wafer Spin Cleaner):

Direct drive by dc servo motor - The motor has a hole through the shaft for the application of vacuum to a chuck. In addition, the hole accommodates an optional accessory substrate lifter. This lifter allows for easier and more precise loading, centering, and unloading of substrates.

Pulse-Width-Modulation - All of our spinners, appropriate for coating substrates, are driven by the Pulse-Width-Modulation (PWM) technique and are closed loop drive systems for precise rpm control. The only spinner products not driven by the PWM technique are the PS80 Manual Wafer Spin Cleaner and factory refurbished or used SCR spinners.

Zero speed sensing for safer operating features - This feature automatically keeps vacuum on the chuck until the substrate has stopped spinning. It may also be used to keep a lid closed, or access doors locked, etc., so long as the spinner motor is turning.

Vacuum control valve reversed logic control - All controllers except the PWM202 have reversed logic control of the vacuum control valve, for power failsafe holding of substrates. The vacuum control valve that applies vacuum to the chuck is normally open (with no power). It is powered off when the vacuum is not needed at the chuck. No power is applied during a spinning operation. Therefore if main power to the system is lost during a spinning process, vacuum to the chuck is not lost and the substrate remains held to the chuck. The PWM202 is being redesigned to conform.

Fume exhaust port - To remove vapors from the spinner bowl. A port to monitor the vacuum in the exhaust system is provided. (Customer supplied exhaust vacuum required)

Digital readout rpm meter (tachometer) (except PS80)

Adjustable acceleration/deceleration (except PS80)

Emergency Abort with maximum dynamic braking

Headway offers 3 standard and 1 special bowl sizes. Spinner systems have within their model number, the actual inside diameter of the bowl (the useable size is reduced by the applicable splash deflectors): R790 (7.9" i.d.), CB15 (15" i.d.), LS22, and the IT22 (22" i.d.). The PS80 (8.0" i.d.) is a limited purpose, manual wafer cleaner/dryer.

Headway offers four standard spinner motors: The PS motor for lighter substrates, to 10,000 rpm, the BD5 ( horsepower) motor for heavy substrates, to 5,000 rpm, and the BD2 ( horsepower) motor for the heaviest substrates, to 2,500 rpm (approximately twice the torque of the BD5). The PM motor, single use exclusively on the PS80 manual spin cleaner, to 7,000 rpm.

Complexity and Level of Automation of the Process: This consideration will determine the type of spin controller, addition of accessory dispensers, exhaust controller, substrate lifter/aligner, etc. Headway currently offers two types of sequence controllers: PWM32: microprocessor based sequence controller; PWM202: simple timer/relay controller for highest power, lowest cost spinning.

To select a spinner appropriate for your application,
there are several things to consider:

Size of substrate (size of bowl required)
Moment of Inertia of substrate (power requirement)
Complexity and level of automation (control system)

Size of Substrate, i.e., maximum dimension: The bowl within which the substrate spins must be large enough to accommodate the spinning substrate. This includes loading, unloading and spinning. Also it is generally desirable to have a "splash deflector" between the spinning substrate and the wall of the bowl in which the substrate is spinning. This reduces the effective opening of the bowl and should be considered when selecting a bowl size. In some cases, users have successfully operated with the splash deflector removed, but a risk of back splash from the wall exists. Headway does not recommend operating without a splash deflector.

Moment of Inertia of the Substrate: Inertia resists acceleration/deceleration and determines the motor power required to achieve a desired rpm in a given period of time. Once running at speed, inertia has little influence on the power requirement, and power is primarily expended on overcoming windage and friction and typical motor losses. If a substrate, or chuck required to hold the substrate, creates significant wind resistance, it may also have a significant influence on the size of motor required.

NOTE: Spinning at high rpm can place very high tensile forces on a substrate, possibly exceeding the tensile strength of the substrate material. This can result in violent disintegration of the substrate. The user must be very careful to consider this factor in determining how fast to spin a substrate.

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Headway Research, Inc.
3713 Forest Lane
Garland, Texas 75042 U.S.A.

Phone (972) 272-5431
Fax (972) 272-7817