SPM Surface Imaging Set-Up Manual
Atomic Force Microscopy
Purpose
This set of instructions describes preparation tasks for MultiModeTM SPM imaging for
undergraduate research students.
Materials
MultiModeTM SPM (Atomic Force Microscope)
Tipholder
Probe
Scanner
Tweezers
Piece of paper
Television to view regular microscope
Contents
I
Preparing and Loading Mica
This section describes how to set-up a piece of mica as a practice substrate to be
viewed under the SPM. Practically speaking, the mica substrate would be imaged once
particles have grown on it but for the sake of learning how to use the SPM, the bare
mica substrate will suffice for the situation.
II
Preparing Probes
Once the mica substrate has been loaded, preparing the probes will follow. The probes
usually come in the form of a wafer, perhaps made of silicon nitride. The wafer must be
carefully cut to extract a few probes from a bulk number of them. The head of the probe
contains the cantilever, a rigid beam-like structure. These cantilevers are small and
extremely fragile. Underneath the cantilevers lies the tip, which is used to scan the
surface of the substrate and determine a profile of its surface features.
III
Loading Probes
Now that the probes have been removed from the bulk wafer, a probe must be carefully
loaded onto the tipholder and then placed in the SPM head.
IV Aligning Lasers
The laser must be properly aligned so that its signal is absorbed by the tip.
V Aligning SPM Meters
Certain parameters must be set in order provide consistent results in SPM imaging.
These parameters can be set by adjusting knobs located on the SPM.
Definitions
Probe
Cantilever
Tip
Mechanical device used to image surface
Rigid beam at end of probe
Pyramid shaped object at end of cantilever used to
detect height changes in surface
Graphic References
SPM
Probe
Cantilever (red)
Tipholder
Spring clip (black ring)
Partition (red)
Wafer
Glass slide underneath (grey)
1 Strip of probes circled (red)
Strip of probes close up
Sawcut (circled)
WARNING
Staring at a bright beam or reflection may cause eye damage. Be sure
magnifier has an installed laser filter.
CAUTION
Use tweezers with probe at all times (cantilever tip easily breaks)
Instructions
Preparing and Loading the Mica
I
1. PRESS DOWN red and white sticky tab
onto sample disk
2. PEEL off sticky tab
3. CUT a small square of mica
4. PRESS DOWN mica onto sample disk
5. PRESS DOWN a piece of tape over mica
6. PEEL OFF the piece of tape
7. COVER mica for later use
Preparing Probes
1. VERIFY silicon nitride wafer is facing
upwards (gold-coated surface facing
down)
2. REST silicon nitride wafer on glass slide
3. APPLY pressure with tweezers to break
strip from silicon ring
4. PLACE strip on piece of white paper under
microscope
5. HANDLE strip on ends only
6. PLACE on glass slide with saw cut on
edge of slide
7. BREAK OFF piece at the saw cut
boundary
8. BREAK OFF probes (4 total) from one
piece of substrate
II
Loading the Cantilever
1. VERIFY probe is facing the proper
orientation. (crosshairs facing up)
2. RELEASE spring clip on tipholder by
applying light pressure with thumb and
index fingers.
3. INSERT probe into spring clip with
cantilever pointing away from clip
4. VERIFY non-cantilever side of probe
touches partition just below the spring clip.
5. HEIGHTEN height of microscope head by
selecting UP on the motor control switch
6. VERIFY head is high enough by coarse
adjustment screws underneath head
anti-clockwise.
7. After verifying (estimate) that the sample is
below tip, PLACE probe and tipholder into
the head chamber
8. TIGHTEN using clamping screw on back
of AFM head.
III
Aligning Laser
1. Use television to view a regular
microscope image
2. ADJUST coarse adjustment screws and
motor control switch to verify cantilever
is close to substrate (cantilever should not
blurry when in focus with substrate)
3. POSITION laser on substrate using
positioning knobs on top of head
4. LOCATE cantilever with laser
5. ADJUST laser onto tip
IV
Aligning SPM Meters
1. LOCATE SUM meter the bottom
of the AFM
2. ADJUST mirror lever on the back
of AFM head to the maximum
voltage on the SUM signal.
3. ADJUST laser adjustment
knobs to maintain half of the
maximum voltage on SUM signal
near cantilever. (Should need to
move left from maximum voltage
near center of cantilever.)
4. ADJUST photodiode
adjustment knobs to an output
VERT/HOR DIFF of 0.00
V
Troubleshooting
References
Veeco Metrology Group. (1996-1999). “Figure 2.2.” full microscope.
Veeco Metrology Group. (1996-1999). “Figure 5.19.” back of SPM head.