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Nanospec 210XP, nanospec2

The Nanometrics Nanospec 210XP system uses non-contact, spectro-reflectometry (measurement of the intensity of reflective light as a function of incident wavelength) to determine the thickness of transparent films (up to two) on substrates, such as silicon, that are reflective in the visible range.

Picture and Location

 Nanospec2 in photolithography area, this tool is located at AB3 on the Lab Map:

nanospec2

 

 

Process Capabilities

Cleanliness Standard

 The nanospec2 appears in all three equipment groups (clean, semiclean, and gold).

Performance of the Tool

What the Tool CAN do

  • pieces to 8 inch wafers
  • Measure thickness of up to two transparent films on a substrate.

 

What the Tool CANNOT do

  • Measure films thinner than 300 A.
  • Measure refractive index.
  • Measure more than 2 thin films.

 

How to Become a User

 

  1. Read all material on the SNF website concerning the Nanospec2.
  2. Contact SNF training contact on the Equipment Summary page.

Operating Procedures

  Introduction

The NanoSpec/AFT Model 210XP located in the photolithography area is a computerized film thickness measurement system for selected small areas. It includes a microspectrophotometer head, which can measure in the wavelength range of 400 - 800 nm, using a computer-controlled grating monochromator, photomultiplier tube detector, and amplifier. The amplifier output is converted to a digital signal by the computer, which then calculates film thickness with one of several algorithms. The front panel includes linear wavelength and photointensity (amplifier output) displays. The head is mounted onto a customized microscope with vertical reflected light illumination, using a regulated tungsten lamp, variable field diaphram, and 5X and 10X parafocal objectives, mounted in a five-position turret.

There is the Operations Manual for the NanoSpec/AFT Model 210XP at the machine.

Film Thickness Measurement

(Keyboard on page 1-12)
(Measurement Theory page 4-2)

  1. Please make no reservation on Coral, first come first serve.
  2. Power should be on.
  3. There should be a test wafers, oxide on silicon, next to the tool. Measure this wafer first to make sure the system is working properly.
  4. Place your piece or wafer on right side of the stage, there should be a blank silicon reference wafer on the left side.
  5. If the display does not show available programs, press <CALIB> F9.
  6. Select the program to be used and press <ENTER>.
    1) Oxide on Si
    2) Nitride on Si
    3) Negative resist on Si
    4) Poly on Oxide (page 3-14)
    5) Negative resist on Oxide
    6) Nitride on Oxide
    7) Thin Oxide on Si
    8) Thin Nitride on Si
    9) Polyimide on Si
    10) Positive resist on Si
    11) Positive resist on Oxide
    12) Reflectivity Mode
    13) Thick Resist (>7 microns - use RI=1.63)

    or press <ENTER> for User Programs

  7. Select the objective to be used (position lens selected and enter the number of lens selected).
    "0" for 5X or "1" for 10X and press <ENTER>.
  8. Please Close UV Shutter (UV option is not available for this tool)
    press <ENTER> to continue.
  9. Scan NEW reference?
    (bare Si wafer on the left side of the stage) If you wish to calibrate with the reference wafer press "<YES>.
    (page 2-4, reference sample should be your substrate material)
  10. Please Focus on Silicon Reference with the objective you selected earlier, press <MEAS>.
    To focus on a bare wafer you should focus on the diaphram (How to focus, page 2-6).
  11. For some programs (such as positive resist on oxide) you will be asked to enter the thickness of the bottom layer (oxide in this case). Enter the number and press <ENTER>.
  12. You will then be asked to "ENTER SAMPLE ID". ID can have as many as 18 characters: all alphabetic characters, numbers, and punctuation are acceptable or just push <ENTER> to continue.
  13. Enter Refractive Index. (page 3-16)
    If you wish to use the standard refractive index for that film, just push <ENTER>.
    If you wish to use a different refractive index, enter it and press <ENTER>.
  14. You will then be prompted to focus on your sample and push <MEAS>.
    The black dot in the center of view must be over the area to be measured (if the area to be measured is smaller that the dot, you must go to a higher power lens-- which means recalibrating to enter the new lens to be used). (5X objective spot size is 30 microns, 10X objective spot size is 15 microns, page 2-8)
  15. Your measurement will come up on the screen. While you make measurements, as many as 60 numbered reading will be displayed on the CRT. It will display "MEASURING" at the bottom of the screen while it is obtaining data or computing results. You may accept or reject readings with the <YES> and <NO> keys. Rejected readings will not be used to compute any statistics.
  16. You can display the statistics for the measurements (page 3-20).
    Press <DISPLAY STATISTICS>:
    Number of Measurements
    Mean Value (in Angstroms)
    Standard Deviation (in Angstroms)
    Press <ENTER> to continue.
  17. Interferogram Graph: <Graph> F7 (page 3-22)
    1. Clear Graph; to erase previously plotted graphic.
    2. Plot Sample
    3. Plot Model
    4. printer is not available
    press Esc to exit
  18. If the thickness is below the measurement capability of the program you selected it will give you a "less than" number (ie less than 100 A if you are using program 1, or less than 20 A if you are using program 7). If the measurement is too high for the program you have selected you may get "OR" for out of range.
  19. This measurement system is very dependent on the reflectivity of the sample. Sometimes if the sample is hazy (ie poly sometimes is) the reading may have a "*" by it. If it is really bad it may have a "?". This indicates that the readings may not be very reliable.
  20. Shutdown
    Press <CALIB>

Refractive Index Measurement

It is recommended to use the Woollam for refractive index measurements.
Use this tool only to measure the refractive index for oxide films.
<CALIB>
<ON/OFF R/1> F6
Calculate Refractive Index? <YES>

Reset (page 2-10)

Press:
Ctrl  Alt  Delete

  1. Enable Datalink? (page 2-12)
    NO
  2. IS WAVELENGTH 480? (page 2-13)
    Check wavelength counter on tool, if it reads 480, press:
    YES
    if not, press NO and follow instructions on page 2-13.
  3. Refractive Index Option?
    YES
    (use only for oxide)
  4. Enable Printer?
    NO
  5. Focus on Reference with 5X Objective Lens (page 2-15).
    (How to focus, page 2-6).
    Ensure yellow filter is in the vertical illuminator.
    Adjust Gain Control so that Photo Intensity Meter Reads between 65.0 and 67.0 (page 1-10 and 1-11)
    press <Enter>

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