Profilometer

Profilometer

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Hi I’m Amanda Harding a graduate student
at Norfolk State University. Today I’ll be demonstrating the Veeco Dektak 6M profilometer.
This instrument is used to measure step heights. After the computer has been turned on we can
go ahead and turn the instrument on which is this switch on the back of the instrument.
So we want to turn the Dektak 32 program on. Once the program is loaded up, we click on
the left a menu, the sample positioning button. That brings up a screen that will show us
the camera view of the sample stage. The next step is to load our sample so we
will open the chamber. Inside we have the rotating sample stage and
it is adjustable with a few of these knobs here and then also it turns.
So we will place our sample. And then back on the program we will click
on this button here which is the “Tower down to null position”, and that will lower
the stylus onto our sample. And as you can see the camera on the instrument
is picking up the view of our sample and the stylus touching it. The brightness is pretty
high usually so we can turn it down and then bring it back up to where we can see much
better. These two knobs move the stage back and forth,
front to back, and then this dial rotates the stage in a circle.
So we will rotate the sample and get in the correct position for the measurement.
So we’ll close the chamber and go back to the program.
The sample that we’re using is a calibration standard and this height here is what we’re
measuring. So we want to set up the stylus so that it’s
going to go across our sample and the stylus is up right now a little bit off of the sample,
so that it doesn’t scratch or damage the stylus, but it’s going to come down right
about in the middle of these crosshairs and that’s how we can line up our sample.
So the next step would be to go to the Window tab, click on “scan routines”, and we
can change the parameters for our scan. So we will enter an ID, the length of the scan,
the duration of the scan. Changing those two parameters will also automatically change
the resolution, and the force of the stylus we can change based on what kind of sample
we have. So if we have a soft sample we want to use a low force and if we have something
like hard sample, we know we aren’t going to damage it, we can use a higher force and
then we will get better resolution. The measurement range is basically if we have
any idea of what height to expect from our features so we know this one is fairly small
we will choose 65 kiloangstroms. The profile is also what you’re expecting
if you don’t really know what to expect you can choose Hills and Valleys, or if you know
you are measuring the depth of a scratch for example you can use Valleys, or if you know
that you’re trying to measure the height of a step height you can choose Hills and that’s
what we’re doing. So then we’ll go back to window click on sample
positioning and click on scan in the left side and that will begin the scan.
So in this box you can see in the background is the camera view of the scan actually taking
place, and in the front is this graph that shows the data that’s being acquired from
the instrument. So the scan is complete, and now we just see
the data. A lot of times when we do these measurements
the instrument does not pick up on how level our simple is so we will want to level it.
We can use these two cursors R and M. We will put them on a two points that we know should
be level so these two points we know should be level and we will click in this toolbar
on “level the trace at the current R and M curser intercepts”.
So now we have something that’s level. Something to note about this instrument–
it measures very small features. So while you have a scale of microns that goes in the
horizontal direction of your sample, the vertical direction of your sample will be on the scale
of angstroms. So once we are ready to take measurements
of our scan we will use these lines, this R line goes all the way vertically up and
down the scan, and the M line. And what we’ll do is we will move these two lines in order
to make our measurements. So we will take the cursor we grab the R and
that moves the entire line. We will put it at the base of our measurement and we’ll take
the M line and move it to the top of the feature, and now will be able to determine the vertical
height of the feature. And that information is located right here,
vertical D, on and that measurement 1002 angstroms. We can also measure the width of our feature.
We move the R line and the M lines just to the edges of our feature. We will see the
horizontal distance between them is about 208 microns.
So we finished our stand we can go up to file, Save As.
We will go into the data file which is located on the desktop.
You can find your folder or if you don’t have a folder you can name one, you may want to
use another folder with today’s date and then you can save your sample.
So when we’re finished we go to the Window tab, and the sample positioning button, we’ll
go over here to the “tower-up to load position” button and that will bring the stylus out
of the way so that you can remove your sample.

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