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KLA-Tencor P15 Profilometer

Table of Contents:
I: Introduction
II: Operating Instructions: Profile Measurement
III: Operating Instructions: Stress Measurement

 

I. Introduction

The KLA-Tencor P-15 profiler is a highly sensitive surface profiler that measures step height and stress on a wafer surface. The key features of P-15 include:

  • A vertical range of 326 um (Do NOT scan more than it).
  • Substrates up to 8 inches, with maximum thickness of 20 mm
  • Stylus forces between 1 mg and 50 mg
  • 2 um of diamond stylus tip with 60° cone angle
  • The maximum horizontal scan length of 80 mm, which is used for stress measurement on a 4-inch wafer with a special stage.
  • Dual-view optics, top-down view and side view

There are three operation screens: Catalog screen , X-Y screen , and Analysis screen . The highest level is the catalog screen where you pick up the measurement tasks, either profiler or stress measure. If you are on the other screen, you need go back to the catalog screen by closing others.

Caution 1: Stylus force should be adjusted based on material being scanned. 2mg and below is okay for resist, it might scratch the resist if above it. Higher forces give more accurate data, but the material being scanned needs to be hard enough (like an oxide or something)

Caution 2: The profiler is placed on an active vibration isolation table that suppresses the low-frequency building noise. Do NOT lean on the table or place objects on top of the instrument.

II. Operating Instructions: Profile Measurement

Recipe

  1. At the profiler catalog screen, highlight and double click the recipe you want to use. If you don't have one, open anyone and save it as yours.
  2. Set the scan parameters in a recipe, especially, the applied force, rang/resolution, profile type, etc. to what are appropriate, then save the recipe.

Loading

  1. Open the X-Y screen by clicking the X-Y icon on the top menu.
  2. Press MAN LOAD button to move the stage close to the door.
  3. Once the stage has moved to the door, open the door and load your sample on the center of stage. Small sample MUST be placed at the very center! Turn on the vacuum switch and close the door.
  4. Press MAN LOAD button again to move the stage back under the stylus head.
  5. Click FOCUS button to bring the stylus head down to the sample surface. The stylus head will move down, touch the sample surface, and lift up automatically.
  6. Move stage to find the feature you want to scan by using the arrows (left, right, up, down) and rotation icons in the menu, or pointing to a location within the circle. The stage moving speed can be Slow, Med, and Fast, but normally at the medium. Zoom in or out if needed, but be sure that the stylus is above your sample.

Scan and Data Analysis

  1. Click the START button if you are ready to scan a feature. Avoid extra vibrations at this moment. The analysis screen will automatically pop up once the scan is complete.
  2. Most of times, you need level the trace. First, click LEVEL button to activate the level function, then move right and left cursors to appropriate positions, and finally click LEVEL button again to finish the leveling process.
  3. Measure the step height by positioning cursors to appropriate locations. The step height and locations are shown on the left side of the window screen. The cursors can be expanded by dragging and pulling a line of the cursor, so you can get an average measurement.
  4. Return to X-Y screen by closing the analysis screen. Data can be saved on grover, but it's not suggested in general.
  5. Repeat the above steps if you want to measure a second feature. Otherwise, go to unloading procedure.

Unloading

  1. On the X-Y screen, press the MAN LOAD button to move the stage to the door.
  2. Wait till the stage is set, open the door, turn off vacuum and remove the sample.
  3. Close the door and log off the tool.

III. Stress Measurement

Generally speaking, the stress measurement needs to be worked on a full size of 4” wafers. Two measurements, pre-stress scan and post-stressed scan, should be done. You need measure and save the wafer curvature prior to coating. Once you coat some known thickness of film, you scan the wafer with the same recipe again. The film stress can be calculated from the two data sets.

Recipe

  1. Click the STRESS icon located on the right side on the catalog screen. Highlight and double click your recipe (You need make one if you don't have).
  2. Set the scan parameters in a recipe. The maximum scan length is 80,000um at the scan start position of x=-40,000 and y=0.
  3. Save the recipe.

Loading

  1. Open the X-Y screen by clicking the X-Y icon on the top menu.
  2. Press MAN LOAD button to move the stage close to the door.
  3. Once the stage has moved to the door, open the door and place the stress holder on the sample stage! Two pins on the plate bottom should fit into the holes on the sample stage.
  4. Load your wafer on the stress holder with the wafer main flat aligned against the two posts.
  5. Close the door, but leave the vacuum OFF.
  6. Press MAN LOAD button again to move the stage back under the stylus head.
  7. Click FOCUS button to bring the stylus head down to the sample surface.
  8. Press the START button to start a (pre-stress) scan. At this time, you'll be asked to assign a name for your data. Type in a name (remember you'll be asked to give a name for the post stress scan, too), and click OK.
  9. Once the scan is complete (a long distance scan), the data screen will pop out. You can measure the curvature and wafer bow by moving the cursors to the appropriate positions. You can also level the trace with LEVEL function.
  10. If this is your pre-stress scan, you need take out the wafer and do a film coating. If this is the post-stress scan, you need go to analysis screen to calculate the film stress. The post-stress scan will use the same scan recipe as the pre-stress scan.

Unloading

  1. Go to the X-Y screen, press the MAN LOAD button to move the stage to the door. Wait till the stage is idle, open the door and remove the sample.
  2. Remove the stress holder from the wafer stage and store it.
  3. Close the door.

Stress Analysis

  1. After you have the pre-stress scan and post-stress scan, go to stress catalog screen and switch to scan data catalog page by clicking the Scan Data icon.
  2. Find the 1 st data set (pre-stress) file, highlight it and set it as the pre stress data by clicking SetPre button.
  3. Then find the 2 nd set of data file, highlight it and press SetPost button to set it as a post scan data.
  4. Click Calculate button to calculate the film stress. Type the film thickness as requested, and click OK. With a further click of OK, the stress result will be displayed.
  5. Record your data or print it. You can also save the data and profile by copy the screen with Print Screen function.
  6. Log off and remember to report any abnormalities to MiRC staffs.