what tapping Engage (and other) settings are needed in V4.43r8 to prevent Engage damage to a FIB Tip (spike) Fres~260 Khz

Mark posted on Fri, Sep 17 2010 1:24 AM

rated by 0 users

Hi,

I am resurrecting an ancient NS3 Phase Extended Multimode. ( a wonderful classic instrument )  I loaded up an FIB tip and began normal engage with default Tapping Engage settings in this software, and saw evidence the $200  FIB2-110s tip (spike section) did not survive the engage

:-(. 

For the next month or so I will have to continue with this software version. I'd be grateful for any pointers to proper MMAFM operation in V443R8 with a FIB tip ( I am lucky to have a J vertical engage scanner - so scanner / sample tilt is not an issue - I had excellent level scans of the same sample with a regular lower aspect ratio tapping tips.

These are defaults? in the Tapping Engage Panel which I used and munched the sharp spike immediately upon engage is my guess.

Engage Delta Setpoint            -0.0200

Engage Final Setpoint                 0.00

Engage Test Threshold              100

Engage Minimum Setpoint %      25

Tapping Mode Engage Gain     3.00

Sew Tip Yes

Sew Trig ( grey'd)                         100

Trigger Safety ( grey'd)             20um

Pre Engage Set Point %               90

Trig Channel                                  Off

Trig Threshold ( grey'd)                  0

Scan Rate                                1.00hz  ( I am guessing this is the sew tip cycling frequency fwiw )

Ramp Step (grey'd)               1.00um

>>>>>>   I will remark I set scan rate to ~0.3 Hz nice and slow, initial XY to ~300nm, then upped to 1um, gains were set to typical 0.7 0.7 ( p&i)  and was attempting to scan a chip with nominal 100nm steps that I imaged prior with a conventional tapping tip.

I have a decent sum signal ~5v and the response spectra looked typical in tuning the cantilever resonance and amplitude. Laser spot near the lever end - nice and clean reflected signal.

When I had setup the tapping frequency tune ( resonance search ) it found a nice peak ~266Khz which was fine, set target oscillation RMS amplitude at ~1.5v no problem, and then initial 1.3v setpoint on approach automatically reduced to ~0.85 v which indicated the settings in tapping engage ( default ) chopped off the FIB spike near immediately ( as corroborated in the image data which was worse acuity / edge resolution than std tapping tips which imaged fine.

Evidence in the image height data indicated the tip was stumpy ( spikeless?).

I'd be grateful for any pointers to proper FIB tip operation ( Veeco Nanoprobe model - p/n FIB2-100s ) with V443R8 software on a Multimode ( I suspect there might be settings outside of the Tapping Engage panel that might be relevant too )

Thanks !