USE OF DEKTAK 6M PROFILOMETER - Login | Nanolab, UCLA

USE OF DEKTAK 6M PROFILOMETER
Prepared by Steve Franz 7/17/03
1

Dektak 6M Profilometer
Introduction:
This spec is an abbreviated procedure on how to operate the Dektak 6M profilometer located in
UCLA's NRF. A more complete manual is available in pdf format on the Dektak 6 computer (C
drive->Dektak->Docs->Dektak 6) and online. In most cases results can be achieved in more than
one way (eg pull down menus or keyboard commands or icons etc). See full manual for more
details and explanations. Also note that a more capable and similar looking machine, the Dektak
8, is also available. For quick scans and ease of use where stage programmability is not needed,
the Dektak 6M may be a better choice.
Operating Procedure:
1 Check the log book to verify the last user had no problems.
2 The Dektak 6M and its computer are usually left on.
a If this is the case, move the mouse to activate the LCD screen. When the
Windows desktop is visible, maximize the D6 program following standard
Windows procedures. This will return you to either the Sample Positioning
window, data window or scan routine window.
b If this is not the case, turn on the Dektak power located to the right of the machine
on the back of the power rack (a bank of LEDs is located on the rack front). Turn
on the computer power located below the Dektak table. If a network login is
requested, double-click the D6 Manual icon to boot up the program. After a
minute or two, the following screen should be seen. Click on the Sample
Positioning Icon (arrow) to bring up the Sample Viewing window.
Fig 1. Main Measurement Screen
2

3 Open the chamber door and verify that the tower and stylus are in the full up position. If
not, raise the stylus and tower by clicking on the
4 Manually move the stage towards you by turning the right stage knob counterclockwise
(see Fig 2).
Fig 2. Wafer stage and controls for Dektak 6M.
5 Position your sample in the center of the stage. Step to be measured should run
horizontally ie left to right in Fig 2.
Note that sample scanning is done by moving the stage from the rear to the front .
However, this image is rotated on the LCD screen and the stage appears to move from
right to left. You must take this into account when you load your sample.
6 Manually move the stage using the x, y and theta knobs to position your sample under the
probe tip.
7 Making sure that your sample is under the stylus, lower the tower by clicking on the
tower down and null icon .
8 Adjust the lighting by either increasing or decreasing the intensity.
9 Make sure the stylus is NOT touching your sample. Adjust focus by turning the lower
focus ring and adjust magnification by adjusting the upper (numbered) focus ring (Fig
3). Magnification may be adjusted from 70 to 280X. Note: Stylus may be raised and
lowered by pressing the yellow F3 key on the keyboard.
3

Figure 3. Magnification and focus adjust
10 The location where the probe tip will touch your sample is given by the center of the
reticle mark (see below). You will want to position your sample so that the location to be
probed coincides with the reticle center.
Note: If there is misalignment of the reticle mark, see the full procedure in the Dektak
6M manual to correct.
Reticle alignment mark
11 Most likely you will want to make some fine adjustments on stage position and rotation.
Proceed as in step 11 WITH THE STYLUS STILL UP.
12 Once the sample is properly positioned under the stylus with the image in focus at the
desired magnification, close the lid on the enclosure and go to the Scan Data Routine to
setup the scan parameters. Click on the scan routine icon to enter this mode.
Note 1: Refer to Dektak 6M manual for setting up Automated Routines which is a
sequence of single scans.
4

13 The scan data window should appear on the LCD as shown below.
14 Click on the SCAN PARAMETERS button and fill in the white blanks below:
SCAN ID: You can leave this blank.
Scan Length: This is the length of the desired scan in microns and must be from 50-
30,000.
Duration: This is the length of time it takes to complete an entire scan. This number
must be between 3-100 seconds for a maximum of 30,000 data points per scan. Select a
longer duration for large scan lengths or very fine surface roughness where high
horizontal resolution is required. For most users a 10-30 second duration is a good start.
Resolution: This is the horizontal resolution expressed in microns per sample so that a
smaller number gives a higher resolution. Since the total number of points sampled is
fixed, the resolution is related to the scan length and scan duration.
5

Stylus Force: This is the force or effective weight of the stylus in mg. The range is 1.0 to
15 mg. For very soft films or high aspect ratio structures using a nanotip, this number
should be lowered. For the average sample, 15 mg is a good selection.
Measurement Range: The available vertical resolution depends upon the measurement
range selected. When measuring extremely fine geometries, use the most sensitive range
(65 Kang) to get a vertical resolution of 1 Ang. For general applications, the 10 Ang
vertical resolution of the 655 KAng range is usually adequate. When measuring thick
films or very rough or curved surfaces, select the 2620 KAng range with 40 Ang
resolution. Finally for very deep or rough structures the 1 mm range may be chosen.
Profile: Valleys should be used where the area to be measured is below the surface since
90% of the measurement range is provided below the zero. Hills provides 90% above the
zero (as for measuring mesas for example) and hills and valleys provides 50% above and
below the zero line. This is the most commonly used mode (except for the calibration
sample). Click the appropriate profile button to select the desired mode.
15 Click OK to exit the Scan Parameters Dialog Box.
16 Click the Display Parameters button in the Scan Routine Window. A Dialog box should
appear as below:
17 If you want the software leveling to be automatic, check the automatic leveling box and
choose a cursor width (20-50 microns is a good start). You must also know the cursor
position, which can be obtained from the data window. Enter these numbers in the cursor
positions box for both the R (reference) cursor and M (measurement) cursor. If you are
unsure of how to do this, uncheck the automatic leveling and level manually as described
below.
18 Choose automatic ranging unless you want to manually set the vertical range of the
graph. Click OK to exit the Display Parameters Box.
19 If Data Processing filtering is desired, see Dektak 6M manual.
20 Click on the “scan” icon to initiate the scan.
21 Assuming the Graphics & Video is selected , the stylus should automatically lower
to the set location and the stage should begin moving. A video image of the stylus as well
as a data screen should be displayed. When the scan is completed, the stylus lifts up, and
6

the stage returns to where the scan originated. A data plot screen similar to below should
be seen on the LCD monitor.
22 In the example above, the plot is obviously not level and so manual leveling needs to be
done. To do so:
A Set the default cursor bandwidth (Plot-->Default Bands) from the pull-down
menu.
B Move the R cursor by using the mouse and clicking to grab and drag the cursor to
one of the reference positions to be leveled. Alternately you can select the R
button (bottom right) and click the appropriate arrow button.
C Similarly, move the M cursor to the 2 nd leveling location. Try to keep the cursors
as far apart as possible for best results.
D Level the plot from the pull-down menu ( Plot _--->Level).
Note 1: If automatic leveling was selected in the Display Parameters Box (step 17) AND
BOTH cursors were properly set, manual leveling should not be necessary.
Note 2: If the out-of-level is very severe such that manual leveling still does not produce
an acceptable trace, mechanical leveling may be necessary and is covered later in the D6
manual.
7

23 The zero point of the trace for this plot may now be set, if desired by moving the R cursor
as described above and then using the pull-down menu (Plot -->Zero ). This will shift the
curve up or down to make the R cursor intercept 0.
24 A quick step height reading can be made by positioning the M cursor at the top of the
step plot and the R at the bottom and then reading the number under Vert D at the bottom
right. HOWEVER it is recommended that you use the delta average step height
measurement for more accurate results. To do this:
A Position the M cursor at the top of the step scan and the R cursor at the bottom.
B Using the pull-down menu select Analysis-->Analytical Functions.
C Under Height select ASH for average step height function
D Click the Measure field at the bottom of the dialog box. If you wish to add the
function to all scan routines select Edit--> Append Function while in the Scan
Routine Window.
E Click the COMPUTE button to calculate the average step height. The result is
displayed in the area to the left of the data pane.
Note: The average is calculated using the default cursor bandwidths selected earlier in
step 22. If the average is to be taken over a wider or narrower plot range, select
Plot-->Bandwidths and enter the number in microns which is desired and then recompute
the average step height as previously described.
25 If desired, a portion of the scan can be re-plotted at a magnified value. Using the mouse,
click and drag over the area to be magnified in the data plot window. When the selection
box turns green, it has enough data to replot. Click the mouse a 2 nd time to set the range.
Select Plot --> Replot from the pull-down menu. Select Plot --> Replot to return to the
original trace. Up to 9 plot boundaries may be saved for a given trace as described later in
the D6 manual.
26 The NRF’s Dektak 6M is equipped with both a floppy and a CD ROM Burner. After the
plot is formatted to your taste you can save it to disk by selecting File-->Save as and
navigating to the appropriate drive following standard windows procedure.
27 If more scans on the same sample are desired, go back to the sample positioning window
by selecting Window-->Sample Positioning from the pull-down menu. With the stylus
up, manually reposition the stage and refocus and readjust magnification if necessary.
Continue to follow the above procedures to obtain a new scan.
28 When you are through with your sample, press the tower up icon, and manually
move the stage out to unload your sample. Remove your sample and position your next
sample on the center of the stage if desired and move the stage back under the stylus.
Continue as in steps 7 to 26 above.
8

29 If you are through using the Dektak, make sure the stage is centered and the tower is up.
Turn off the illumination using the dim icon , close the chamber door and minimize
the D6 Manual program. It is not necessary to shut down Windows or the computer.
30 Fill out the log book completely. Don’t forget to remove your floppy or CD if you
brought one.
9