Micro Cantilevers

for Electric measurements

Catalog number

	Small quantily unit	Wafer unit
	18 chips/unit	375 chips/wafer
Small spring constant (k) type Silicon probe with platinum coating	OMCL-AC240TM-B2	OMCL-AC240TM-W2

OLYMPUS OMCL-AC240TM- series cantilevers; platinum-deposited cantilevers are suitable for conducting scanning probe microscopy (SPM) in air such as electric force microscopy (EFM), Kelvin probe force microscopy (KFM). Unprecedented sharpness of 15nm (typ.) radius as a metal coated probe is worth trying in researching devices.

Platinum-deposited Tetrahedral tip cantilever

Outstanding features of Tetra tip cantilever

1) High electrical conductivity:
The platinum-deposited probe shows lower conductivity in one and a half orders of magnitude than that of highly doped silicon probes. Its probe resistance of 350 ohms is sufficiently low for electric measurements required high electro-potential resolution. The surfaces of precious metal coatings are free from oxidization and are electrically stable.

2) High resolution:
The apex of 15 nm (typ.) radius is prominently sharp among metal-coated probes (see the tip apex). The thin and sharp tetrahedral probe reveals sample surface precisely both in electrically and in topographically.

3) Easy to access where you want to see:
OMCL-AC240TM- Series has a tetrahedral tip on the exact end of the cantilever. Since the tip isn't hidden by the body of cantilever, it can be positioned exactly at a point of interest using an optical microscopy. - Tip View feature - Click here for an example (image size 40k)!

Check Scan line profile

Tip

Below are a schematic sectional view and SEM images of a platinum-deposited silicon tetrahedral tip.

• Tip shape : sharpened tetrahedral (tilted)
  It shows good symmetry viewed from the front and is inclined viewed from the side.
  Considering this geometric feature, choose the fast scan (X) direction.
• Tip height : 15 µm (9 to 19 µm)
• Tip radius : smaller than 25 nm (15 nm (typ.))
• Tip angle : less than 35 degrees ( *)
• Tip-side coating material : platinum with thickness of 20nm on the lever portion
• Basic tip material : single crystal silicon (semiconductor, N type, 4 - 6 ohm.cm)

Dimensions of levers and chip (substrates)

Cantilever and chip of OMCL-AC240TM series

Lever thickness of OMCL-AC240TM- is typically 2.8µm.

Cut off shoulders lessens contact between the chip and the specimen when the tip has engaged to the sample (illustration right above).

Metal coating

[Tip-side coating]

• Coating material : Platinum
• Thickness of platinum : 20 nm (at the lever portion)
• Probe resistance : Approx. 350 ohms

note:
Probe resistance is studied with the setup illustrated in right.

• Position to electrical contact

In attaching the probe chip to your SPM instrument, ellectrically connect to the chip in the cantilever side for stable measurements (see illust. right). It is not expected that the aluminum layer (reflex coating) shows enough conductivity because the surface of the aluminum layer is covered with oxide layer.

[Reflex coating]

• Material : Aluminum
• Thickness of aluminum : 100 nm

Mechanical properties of levers

Stiffness [N/m] and resonant frequency [Hz] of each cantilever are Calculated values<.

Mechanical Q factors of OMCL-AC240TM- from 100 to 200 in air, are measured in our experiments. However, the final properties deeply depend on the holding condition of the chips in your AFM.
In vacuum, the Q factor increases up to 10 times.

Packaging

Small quantity unit : OMCL-AC240TM-B2

• Number of chips in a case : 18 chips
• Case : Gel-Pak container
• Chip status : Pre-separated
Chips are separated from each other and are placed in the Gel-Pak.

Inspections are carried out when the chips are in the wafer stage; those which pass the strict quality test are placed on the gel sheet ready for supply.

Wafer type unit : OMCL-AC240TM-W2

• Number of chips in a wafer : 375 chips
• Case : 4 inch wafer case (not Gel-Pak)
• Chip status : supported to frame with support arms

Chip separation from the wafer is easy due to the frame structure (Illust. above).

Wafer pattern of OMCL-AC240TM-W2 ( 4 inch. wafer ) is shown in the above photo.
Tip inspections are performed by sampling 10 tips at random from the wafer. (Blank area in the wafer)

Applications

• Microscopic / nanoscopic measurements of electric characteristics of semiconductor devices
  such as electric force microscopy (EFM), Kelvin probe force microscopy (KFM) operating in AC mode.
  With care for tip worn, OMCL-AC240TM- is also available for scanning capacitance microscopy (SCM) and scanning spreading resistance microscopy (SSRM) in contact mode.
• Scanning probe lithography
• Nanometer-tool applications for nano-technology and nano-biology research
  Electric knife, stick, scraper. Small electrode.