JPH0430921A - Probe for interatomic power microscope - Google Patents

Abstract

PURPOSE:To enhance the resolution and perform accurate measurement by providing the head section of a plate with an electrolyticaly ground needle like tip and making it faithfully trace the surface shape of specimens. CONSTITUTION:An electrolyticaly ground needle like tip 1 is provided in the head section of the plate 2 of a probe for inter-atomic power microscope. Owing to this constitution, this head section can be sharply constituted, and the power that the atomic of the head of this tip receives can accurately detected, and the surface shape or the distribution of force can accurately measured without errors on the surface of specimens 5.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a probe used in an atomic force microscope for observing minute structures on the surface of a sample.

[Prior Art] FIG. 3 shows the configuration of a conventional atomic force microscope (AFM). The part of the plate (2) on which the chip (1) is formed is a probe, and is fixed to the substrate (4). A sample for observation (5) is mounted on an xyz-scanning system. When the tip of the tip (1) and the sample (5) are brought close together by the Z-drive device, a repulsive force due to Pauli's exclusion law acts between the surface of the sample (5) and the tip (1), and the plate (2)
). This deflection, that is, the amount of displacement is detected by a displacement detector (6) using optical means or the like. In addition, by scanning the sample (5) while controlling the position of the tip with a Z-drive device using a piezoelectric element, etc., so that the detected displacement amount is constant, the structure of the surface is atomically determined. What you can know is based on the resolution of the scale. At this time, the shape of the tip tip is considered to be a major factor in determining the resolution of this microscope. That is, the sharper the tip of the tip, the better the resolution.

[Problems to be Solved by the Invention] As a conventional technique, there is a method in which a needle-shaped tip is formed integrally with the tip of a plate made of silicon oxide or silicon nitride using semiconductor lithography technology. Even in probes made by this method, the sharpness of the tip tip still needs to be improved.

An object of the present invention is to provide a probe having a sharp needle-like tip at the distal end of the plate.

[Means for Solving the Problems] The above object is achieved by providing an electrolytically polished needle-like chimney at the tip of a plate of a probe for an atomic force microscope.

[Function] According to the present invention, since the tip of the plate is provided with an electrolytically polished needle-like tip, it can be configured to be sufficiently sharp, and the force exerted by the atoms at the tip of the tip can be accurately detected.
It is possible to accurately measure the surface shape, force distribution, etc. without any errors on the sample surface.

Furthermore, electrolytic polishing can sharpen the tip with a simple operation.

[Example] Next, the atomic force microscope probe (AFM probe) of the present invention will be described based on an example.

FIG. 1 shows an AFM probe with a metal needle tip at the tip. The probe has a structure in which the plate portion (2) bends when subjected to atomic force. By forming the needle tip (1) protruding outside the plate surface as in this structure, the AFM probe has high sensitivity.

Next, a typical probe manufacturing method will be described. Second
The figure is an explanatory diagram of a method for manufacturing the probe shown in FIG. 1.

First, a silicon nitride film (9) is formed on a 31 wafer (8) (a). Next, resist (1
0) and b) are exposed and developed to form a triangular pattern that will become the plate portion (C). Next, the silicon nitride film (9) is dry-etched using reactive scum such as CF a, and then the resin 1- (10) is peeled off (d).
Next, a resist (IO) is coated on the back surface, and a pattern for Si etching is formed (e). The surface is coated with a resist (10) and then a mask (16) to form windows for depositing metal chips by photolithography. At this time, use diffracted light to create an undercut as shown in the figure (f) W, Ni
Metals such as Cu, Pt, and Cr, or alloys thereof;
Chips (
1) Form (g) Next, peel off the resist (10) (h) On top of this, a 3102 film (12) is formed to serve as a protective film during silicon etching (1).

Next, silicon etching is performed to form bullet (2) (j) Sarani S i O21! ! j! (12)
Remove with hydrofluoric acid (k) Form a thin conductive film (13) on the plate (2). Gold, silver, carphone, etc. can be used as the material for the membrane, and gold is most preferably used (1). After this, the plate (2) is used as an anode in a KOHi solution (14), and a platinum electrode (15) is used. 4 as negative electrode
Electrolytic polishing is performed without applying a voltage of 0 to 50 V (m) In this example, when forming a chip by vapor deposition, a window with an undercut is used, so the deposited chip (1 ) has a protruding tip, so even if the electrolytic polishing time is short, the tip will be sufficiently sharp.

In addition to silicon nitride, it is also possible to use a film of silicon oxide or the like for the plate portion.

Incidentally, the conductive film may be grounded as an electrode for carrying out electrolytic polishing, and is not necessary as it may be grounded on the tip (2) at the tip.

Note that when a metal film is deposited as a sorting electrode on the plate surface as in this example, when measuring the amount of displacement by applying a laser beam, the metal film becomes a good reflective film and the reflectance increases. The effect of improving the SN ratio can be obtained.

[Effects of the Invention] As is clear from the above description, the present invention can provide a probe with a highly accurate sharp tip. As a result, the tip at the tip of the plate faithfully traces the surface shape of the object to be measured, making it possible to measure the shape with high resolution and precision.

[BRIEF DESCRIPTION OF THE DRAWINGS] FIG. 1 is a general view of a probe made of silicon nitride showing an embodiment of the present invention, and FIG. 2 is a cross-sectional view showing an embodiment of the probe manufacturing method of the present invention. FIG. 3 is a block diagram showing a conventional atomic force microscope (AFM). [Explanation of symbols of main parts] ・・・Chief 2・・・Plate・・・Fub, ・・・Base, ・・・Sample, ・・・Displacement detector, ・・・・xyz-scanning system

Claims (1)

[Claims] An atomic force microscope probe characterized by having an electrolytically polished needle tip at the tip of the plate.