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Alphastep 500

The Tencor Alphastep 500 is a stylus-based surface profiler to measure step heights of surfaces. A stylus is placed in contact with, and then gently dragged along the surface of the substrate. The vertical deflection measures the change in step height.

Picture and Location

 Alphastep 500

The tool is located at B23 on the Lab Map.


Process Capabilities

Cleanliness Standard

The Alphastep 500 is in the Gold Equipment Group

Performance of the Tool

  • Step heights from 500 Angstroms to 300 µm
  • Scan length from 100 Angstroms up to 0.3 mm
  • Stylus radius 5 µm (yellow ring)
  • Ranges and resolutions:
     13 µm at 1 A
    300 µm at 25 A
  • Zoom optics with magnification up to 210x
  • Max sample dimensions:
    150 mm (6 inch) wide
    15 mm (.59 inch) thick
  • Multi-scan average mode scans up to 10 times

What the Tool CANNOT do

  • no printer
  • no data saving


How to Become a User

  1. Read all material on the SNF website concerning the Alphastep.
  2. Contact SNF training contact on the Equipment Summary page.


Operating Procedures


No reservations, first come first serve.

Enable alphastep.

Power is left on.

Switch on screen.

Load wafer (4.2)

  • Make sure the stage table is in a low position, if not press and hold the up arrow key to lower the stage.
  • Turn the y-axis adjustment knob to move the stage forward.
  • Place your wafer on the center of the table and move the stage backward until your wafer is under the stylus.

Raising the stage table (4.3.1) and positioning wafer (4.3.2)

  • Press Z (F5) key.
  • Press and hold the down arrow key to move the stage up until the stylus stops on the wafer surface.
  • Press the up arrow key to lift the stylus up (never move the wafer while the stylus is on the wafer surface).
  • Turn x and y knobs to move sample into position.
    CAUTION: Stylus should be retracted before moving the stage!
  • Turn the Zoom knob clockwise to increase magnification of the video image.

Profiling from a scan recipe (4.4)

  • Press Escape key.
  • On the menu bar, use right or left arrow keys to select Recipe and down or up arrow keys to select Catalog, press Enter.
  • Use down or up keys to select desired recipe and press Enter.
  • Writing and editing a recipe (5.0)
    To edit an existing recipe, press the up or down keys to select one line and to change values press the right or left arrow keys. Some fields have fixed values other fields you can type in the value from the numeric keyboard.
    • Vertical Range:
      Choose 13 um range for step heights between 500 A and 13 um.
      Choose 300 um range for step heights between 13 um and 300 um.
    • Profile type:
      In the 300 um range, you have to choose one of three choices: center, peak, valley bias.
  • Saving recipes (5.4)
    Don't change an existing recipe! If you would like to create your own recipe, open an existing recipe, make changes, press [F1:Save], type your own recipe name, and press Enter.
  • Starting the scan:
    Press Start (F8) key to start the scan (don't touch the tool or table during the measurement!).
    You can press STOP (F9) key to abort a scan at any time.
    When the scan is completed, the stylus lifts up and the Data screen is displayed with the profile plotted in dimensional coordinates.

Leveling the Profile (7.2)

  • Wait until the "Rehoming after scan" is done.
  • Press LEVEL (F10) key if the trace is not horizontal. The leveling cursors L (left) and R (right) will appear, the activated cursor appears red.
  • Move red cursor to the desired position with the arrow keys.
  • Press spacebar to activate the other cursor and position it. You can press the spacebar twice quickly to activate L and R simultaneously.
  • Press LEVEL to level the trace. (Press backspace + LEVEL to return to the previous trace if necessary.)

Analyzing the scan (7.3)

  • Move L and R cursors to the desired positions.
  • Reading the data (7.4.2) in the summary box:
    Height - Vertical distance between trace intersections of cursors (in Delta Average mode, the vertical distance between the average values of height within the two delta width regions).
    Width - Horizontal distance between the cursors.

 Unload wafer and shutdown

  • Press Z key.
  • Lower stage using up arrow key.
  • Move stage forward and unload wafer.
  • Switch off screen.
  • Leave power on.
  • Disable alphastep.


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