Micro Cantilevers

for AC (dynamic) mode AFM

Catalog number

	Small quantily unit	Wafer unit
	24 chips/unit	375 chips/wafer
Standard Silicon probe	OMCL-AC160TS-C2	OMCL-AC160TS-W2

OLYMPUS OMCL-AC series cantilevers are designed for AC mode AFM in air.
OMCL-AC Series has a tetrahedral tip on the exact end of the cantilever. Call it " Tetra tip" !

Tetra tip cantilever, 160um long, 50µm wide

Outstanding features of Tetra tip cantilever

1) Easy to access where you want to see:
A Tetra tip is located on the very end of the cantilever. This allows you to set the tip over a point of interest on the sample, easily and precisely, if you use an AFM combined with an optical microscope. Click here for an example (image size 40k)!
Look again at the SEM image above! This explains the easiness in an AFM combined with an optical microscope.

2) High lateral resolution:
A sharper tip is required for revealing a sample surface much more precisely. Tetrahedral shape is ideal for obtaining a point terminated tip. Actually, the radius of the curvature of the Tetra tip is very small and the average is less than 10nm even with the Aluminum reflex coating.
OMCL-AC160TS- series covers a wide range of applications, however, it is outstanding in the observation of crystal surfaces, thin film, IC devices and so on.
Click here to assure the effectiveness of the Tetra tip (image size 80k).

3) Observation of rugged samples:
The Tetra tip is thin with the tip angle of 35 degrees (scroll up this page more to see the SEM pictures). So this tip enables you to observe a narrower part of the sample.
Furthermore, the Tetra tip is a tilted tip, so substantial tip angle decreases more when it is attached to a chip holder in your AFM with certain tilt angle (probably, 5 to 20 degrees).
The tetra tip is effective for observing a rugged samples.

Check Scan line profile and enlarged view of the tip apex.

<note:>
Many researchers in biology and chemistry field have interests in AC mode AFM in fluid. For measuring a soft sample like a biology cell, OMCL-TR and -RC series cantilevers are recommended rather than OMCL-AC series cantilevers. See the sample images taken by OMCL-TR400PSA- and OMCL-AC120TS-.

Tip

Below are SEM images of a Tetra tip from the front and side, and the last is a magnified view from side (picture size: 900nm x 680nm).

• 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 : 14 µm (7 to 15 µm)
• Tip radius : smaller than 10 nm (7 nm (typ.))
• Tip angle : less than 35 degrees (*)
• Tip material : single crystal silicon (semiconductor, N type, 4 - 6 ohm.cm)

Dimensions of levers and chip (substrates)

Cantilever and chip of OMCL-AC160TS series

Lever thickness of OMCL-AC160TS- is typically 4.6µm.
Cut off shoulders lessens contact between the chip and the specimen when the tip has engaged to the sample (illustration right above).

Metal coating

[Reflex coating]

Thin aluminum film with the thickness of 100nm is coated on the cantilever for reflecting light from the deflection sensor in the AFM equipment. High reflex for high S/N sensing can be expected.

Mechanical properties of levers

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

Mechanical Q factors of OMCL-AC160TS of about 500, are measured in our experiments however the final properties deeply depend on the holding condition of the chips in your AFM.
(Q factor of OMCL-AC240TS- is from 100 to 200 in air.)

In vacuum, the Q factor increases up to 10 times.

Packaging

Small quantity unit : OMCL-AC160TS-C2

• Number of chips in a case : 24 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-AC160TS-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-AC160TS-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

• We recommend OMCL-AC160TS- as a standard cantilever for imaging the sample topography in AC mode AFM in air because of its high Q factor.
• Nanometer-tool applications such as bio cell scraping
• Raw material for making carbon nanotube tips