Instruction manual

Calibration, Maintenance, Troubleshooting and Warranty
Fluid Imaging Troubleshooting
Rev. B MultiMode SPM Instruction Manual 323
15.12.5 Image goes white or black
If the image goes white or black after a few scans and the Z Center Position voltage is still within
range, check the Offline Planefit sub-command on the control monitor. Offline Planefit is normally
set to Full. (See full description of the Offline Planefit command in Digital Instrument’s Command
Reference Manual.
15.13 Fluid Imaging Troubleshooting
15.13.1 Image drifts
Occasionally, there may be some image drift due to the O-ring (used to contain fluid) sliding across
the sample surface. To reduce movement of the O-ring, the fluid cell needs to be set up such that
there is minimal lateral movement of the SPM head with respect to the sample once the O-ring is
installed. This is best accomplished by keeping the head level and positioning the tip as closely as
possible to the surface before installing the O-ring so that the lateral movement of the tip during
engagement is minimized. Also, moving the positioning screws at the bottom of the optical head
should also be minimized once the O-ring is installed. Further suggestions for solving this problem
consist of the following:
• Use the fluid cell without the O-ring as described in Chapter 7 of this manual. This
technique works best on hydrophobic surfaces. If you have a surface that does not allow
a liquid drop meniscus to form or stabilize (e.g., mica), a water repellent marker may be
used to outline a boundary for holding the drop. This type of marker, the “PAP PEN,”
can be purchased from the The Binding Site, 5889 Oberlin Drive #101, San Diego, CA
92121; 1-800-633-4484; Fax: [phone].
Note: For applications where fluid flow is necessary, this option should not be used.
Be certain to check for leaks and wipe up any spilled fluid as soon as possible to
avoid damage to the scanner.
• The new vertical engage scanners allow the tip to approach the sample without the
lateral movement caused by the stepper motor. Thus, lateral stress on the O-ring is
absent. Vertical engage scanners are available in the 125µm (“J”), and 10µm (“E”) sizes.
Contact Veeco for more information.
• Lightly coating the area of the O-ring which contacts the sample surface with white
petrolatum or vacuum grease will allow the O-ring to slide across the surface,
minimizing lateral stress. This also forms a better fluid-tight seal between the O-ring
and sample. Be aware that some solvents (e.g., non-polar organic solvents) may dissolve
some lubricants into the fluid.