Prepare and Load the Probe Holder

Install probe substrates face-up so the tip points away from the probe holder. This ensures that the cantilever and tip face toward the sample once the probe holder is mounted on the scanner.

For more detailed information, see Unmounted Probe Handling and Loading a Probe on the MultiMode.

To install a probe on the AFM cantilever holder:

1. Using sharp tweezers, grasp the substrate firmly on the sides and lift to free the substrate from the wafer or gel-pack. In the gel-pack boxes the tip ends are pointing upward and do not need to be turned over before being placed in the cantilever holder.

2. Many silicon nitride substrates have cantilevers on both ends of the substrate. If this is the case, place the substrate under an optical microscope or magnifier and locate the tip you want to use.
3. Turn the probe holder upside down with the groove facing up.
4. With the probe holder on a level surface (e.g. the table top), apply gentle downward pressure. This will push the plunger and lift the spring clip.
5. With the spring clip lifted, carefully slide the probe into the probe holder's groove until it is located squarely against the innermost edges.
6. Lower the spring clip by releasing pressure against the plunger. This will hold the probe securely in the probe holder’s groove.

Install the Probe holder

After the probe holder is loaded with a probe, place the probe holder inside the SPM head and clamp it into position using the clamping screw at rear of head.

1. Verify that the head is sufficiently raised to clear the sample with the tip. The top of the sample should not protrude more than 1–2 mm above the inside head bottom plate and is safer if set so the sample is flush with the plate. Excessive protrusion risks a crash between sample and tip when the probe holder is installed.
2. Insert the loaded AFM probe holder into the MultiMode 8 head by placing the probe holder carefully over the sample. Do not touch the sample with the probe holder.
3. Push the probe holder forward gently and lower it into position:

Three precision ball mounts inside the head mate kinematically with the probe holder underside. If the scanner cap has been properly positioned, the probe holder will come to rest with the probe just above the sample surface. If the scanner cap is adjusted too high, the tip will be plunged into the sample surface and broken. If it appears the probe may crash when the probe holder is installed, remove the probe holder completely and use the Up switch on the MultiMode 8 base to obtain sufficient clearance. Inexperienced users should practice with scrap probes and samples to learn proper loading procedures.

4. Rotate the clamping screw clockwise to secure the probe holder in place:

Adjust the Tip Height Over the Sample Surface

Use the adjustment screws to adjust the probe height to just above the sample surface. The coarse adjustment screws on the scanner (if so equipped) are located in front and may be used to make gross adjustments. The probe should be positioned just high enough to reach the surface when engaged, but not so low as to risk crashing into it. Use the motorized screw to ensure the head is reasonably level (this is not a concern with single-screw scanners).

One method employed to adjust the height of silicon nitride tips on noncritical samples is to very slowly lower the tip using the adjustment screws until a sudden change is noted on the sum display of the MultiMode 8 base. Most silicon nitride cantilevers are flexible and may be gently touched to the surface without damage to either the tip or the surface if the tip is lowered slowly. Watch for the change on the sum signal display! When the SUM signalThe sum of all four photodetector quadrants (A+B+C+D); indicates how much laser power is reaching the detector. Reflective cantilevers have a higher SUM signal than non-reflective cantilevers. The first step of aligning the laser is to ensure that there is sufficient SUM signal measured from the detector. change is noted, stop lowering immediately. The Tip Up switch may then be toggled briefly to lift the tip just above the surface (the SUM signal should resume its normal value). This method works well on samples which are not delicate and which can be imaged without concern for damage.

Previous Steps:

1. Select Experiment
2. Prepare and Load the Sample

Next Steps:

4. Align the Laser
5. Maximize the SUM Signal

When working in TappingMode, the next step at this point is to tune the cantilever. See Manual Cantilever Tuning for more information.

6. Check Initial Scan Parameters
7. Engage, Scan, & Withdraw

Open topic with navigation