Microelectronics Research Center

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Heraeus Vacuum Oven

The Heraeus Vacuum Oven is used to heat samples up to 400 degrees Celsius inside a vacuum, below 20 mTorr. The oven has a controller, allowing the user to program in a recipe that includes multiple ramping times, dwelling steps, and cooling steps.

There are multiple options when using the Heraeus Vacuum Oven. It can be used at atmosphere, under vacuum, with a pre-programmed run, or with a manually set temperature.

Vacuum
To pump the system down you must first load your sample, and then close the door, locking it by turning the handle. Turn the vacuum gauge counter clockwise. The system will then pump down to less than 20 mTorr.

Programmer
There are 3 programmers per oven. The central programmer is the Master programmer. Each programmer has an upper readout and a lower readout on the screen. The upper read out is the measured temperature while the lower readout is the set point. On the programmer are 6 buttons: RUN/HOLD, AUTO/MAN, SCROLL, PAGE, UP, and DOWN.

The Auto/Man button changes the programmer from Automatic mode to Manual mode.

  • Automatic Mode: The controller automatically maintains the setpoint.
  • Manual Mode: This mode allows you to change the setpoint by using the UP and DOWN buttons.

The controller will be in one of five states:

  • Reset: Both the RUN and HOLD lights are off. This means the programmer is inactive.
  • Run: The RUN light is on. The programmer varies the setpoint according to an active program.
  • Hold: The HOLD light is on. The program is frozen at the current point. You can make temporary changes to parameters, but these changes will only remain until the program is rest and run again, then the stored value is used.
  • Holdback: The HOLD light flashes. This indicates the measured value is lagging by more than a preset amount, and the program is waiting for the process to catch up.
  • End: The RUN light flashes. This shows that the program is complete.

To run without a program:
In order to run a process without a program, turn the machine onto Manual Mode by pressing the Auto/Man button. Then use the up and down arrows to choose your temperature. The machine will then adjust to the temperature set on the controller.

To create a program:
This section will teach you how create or modify the existing program, the following steps must be used.

  1. From the Home display, press the page button until you reach ProG LiST.
  2. Press the scroll button.
  3. The Hb screen appears. Press the up or down button to select:
    1. OFF: Holdback is disabled and no action is taken.
    2. Lo: Deviation low holdback. This means the program will hold when the process deviates below the setpoint by the holdback value.
    3. Hi: Deviation high holdback. This means the program will hold when the process deviates above the setpoint by the holdback value.
    4. bAnd: Deviation band holdback. This means the program will hold when the process deviates above or below the setpoint by the holdback value.
  4. Press scroll again.
  5. Hb U appears. This is where you set the holdback value. Press the up or down button to set the value. The set value is for the whole program.
  6. Press scroll again.
  7. rmp.U appears. This is where you can set the ramp units. Use up or down to select:
    1. SEc: seconds
    2. min: minutes
    3. Hour hours
  8. Press the scroll button
  9. dwL.U allows you to set the dwell units using the up or down buttons. It gives you the same unit options as the ramp unit options.
  10. Press scroll again
  11. CYC.n allows you to choose the number of times the program is cycled through.
    1. 1 to 999 or cont for continuous cycling
  12. Press scroll
  13. SEG.n lets you choose the segment number. Each section of the program (ramp, dwell, etc) is a different segment number.
  14. Press scroll
  15. tYPE appears. This is where you choose the segment type. The different segment types are:
    1. rmP.r: Ramp to a new setpoint at a set rate
    2. rmp.t: Ramp to a new setpoint in a set time
    3. dwEll: Dwell for a set time
    4. StEP: Step to a new setpoint instantaneously
    5. cALL: Call another program as a subroutine
    6. End: Make this segment the end of the program
  16. Each segment type has a few parameters to help define it. The function of the parameters are:
    1. tGt: Target setpoint: for rmP.r, rmP.t, or StEP segments. Use the up and down arrows to set the setpoint.
    2. rAtE: Ramp rate, for rmP.r segments. The units were defined earlier by rmP.U.
    3. dur: duration time: Time for dwEll segment or time to target for rmP.t segment. Use the up and down arrows to set.
    4. PrG.n: Called program number, only appears for cALL segments
    5. cYc.n: Number of cycles of the called program, only appears for cALL segments
    6. End.t: End segment. Use up or down to select:
      1. dwEll: an indefinite dwell
      2. rSEt: reset to the controller setpoint.
      3. S OP: End segment output power level
  17. Press scroll to return to the ProG-LiSt header