Medium-soft Silicon Cantilever Classic
for AC (dynamic) mode AFM
|Small quantily unit||wafer unit|
|24 chips/unit||375 chips/wafer|
|Small spring constant (k) type Silicon probe||OMCL-AC240TS-C2||OMCL-AC240TS-W2|
OLYMPUS OMCL-AC240TS- series cantilevers are designed for AC mode AFM in air to measure soft samples.
OMCL-AC240TS- Series has a tetrahedral tip on the exact end of the cantilever. Call it " Tetra tip" !
Tetra tip cantilever, 240um long, 30um 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 the SEM image above! That could explain the easiness in an AFM combined with a scanning electron microscope.
2) High lateral resolution:
A sharper tip is required for revealing a sample surface precisely much more. 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-AC240TS- series covers over wide range of applications, however, it is outstanding in the observation of soft samples like biology cells, DNA strands and so on.
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.
Further more, the Tetra tip is an tilted tip, so substantial tip angle decrease 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.
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-.
Below are SEM images of a Tetra 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 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-AC240TS series
Cut off shoulders lessens contact between the chip and the specimen when the tip has engaged to the sample (illustration right above).
Lever thickness of OMCL-AC240TS- is typically 2.7 µm.
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 cantilever are Calculated values.
(0.7 - 3.8)
(50 - 90)
(9 - 19)
Mechanical Q factors of OMCL-AC240TS- 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.
Small quantity unit : OMCL-AC240TS-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-AC240TS-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-AC240TS-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)
- AC mode AFM imaging of Soft samples in air
We recommend OMCL-AC160TS- as a standard cantilever for the measurement in AC mode AFM in air.
OMCL- AC240TS- cantilever is softer than OMCL-AC160TS- cantilever so that it is used when the customers should control the tip loading force in small for avoid big damage of the samples and/or the tips.
If your measurement of sticky samples with OMCL- AC240TS- tend to become unstable, we recommend you try a stiffer cantilever like OMCL-AC160TS- instead of this soft cantilever.
- OMCL-AC240TS- must be selected if the band width of the circuit in your AFM is limited in (dc) - 100kHz.
- Force modulation measurement
- Nanometer-tool applications such as bio cell scraping
- Raw material for making carbon nanotube tips
- Care for Static shock (see an example of tip damage)
The sharper tip needs the more careful handling to prevent static damage to the tip. Use of an anti-electrostatic mat and a wrist band are recommended as when handling laser diode chips. Handling under an ionizer is also recommended.
Please avoid wearing clothes like woolen sweaters, fleece etc when handling the cantilever cases and chips.
- We guarantee more than 90% good cantilevers in this product series. Every good cantilever meets the specifications.
- FAQs on AC (dynamic) mode cantilevers (here)
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