Small quantily unit	wafer unit
	24 chips/unit	375 chips/wafer
Small spring constant (k) type Silicon probe	OMCL-AC240TS-C2	OMCL-AC240TS-W2

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.

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-.

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 : 14 micrometers (9 to 19 micrometers)
  
• Tip radius : smaller than 10 nm (6.8 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

Lever thickness of OMCL-AC240TS- is typically 2.8um.

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

Metal coating

Mechanical properties of levers

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

	Lever					Tip
	thickness (um)	length (um)	width (um)	spring const. (N/m)	resonant freq. (kHz)	height (um)	radius (nm)
OMCL-AC240TS-	2.8	240	30	1.8 (0.7 - 3.8)	70 (50 - 90)	14 (9 - 19)	< 10

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)
  
  

Applications

• 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)