JPH11160334A - Probe for scanning probe microscope and method for detecting force - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a probe for scanning probe microscope which can be inserted into the very narrow groove, etc., of a semiconductor sample and can detect an interactive force between the probe and the internal surface of the sample, and a method for detecting the force that acts on the probe. SOLUTION: A probe for scanning probe microscope is provided with a supporting section 2, a probe section 4, and a detecting section 3 which is positioned between the supporting section 2 and the probe section 4 and detects an interactive force between the probe section 4 and a sample, with the detecting section 3 and the probe section 4 being substantially formed on the same axis. Since the detecting section 3 and the probe section 4 are formed on the same axis, the spatial restriction to the probe section 4 becomes smaller and the section 4 can be inserted into the very narrow groove, etc., of the sample. When the probe is excited to make torsional resonant motions and the change of the torsionally vibrating state of the probe which occurs when a force acts on the probe section 4 is detected, the interactive force between he section 4 and the sample can be detected with high sensitivity.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a probe of a scanning probe microscope and a method of detecting force, and more particularly to a probe of a scanning probe microscope suitable for measuring a sample having fine irregularities. The present invention relates to a manufacturing method and a method for detecting a force acting between a probe and a sample.

[0002]

2. Description of the Related Art In a scanning probe microscope, a sharp probe protruding almost vertically from the tip of a small cantilever of a probe is brought close to or in contact with the surface of a sample, and the cantilever is scanned relative to the sample. By utilizing the physical or chemical interaction between the surface of the sample and the probe when it is made, the unevenness image on the surface of the sample, the distribution of electrical properties, the heat distribution, etc. can be reduced to a minute scale (for example, nanometers). Of the order).

An atomic force microscope (AFM) for detecting a force between a sample surface and a probe is a typical scanning probe microscope, and acts on the tip of the probe according to the three-dimensional shape of the sample. The change in cantilever deflection caused by force
By detecting with an optical lever method or the like, the surface shape of the sample can be observed with high resolution and precision.

In the industrial field in which a scanning probe microscope such as an atomic force microscope is widely used, particularly in the field of semiconductors, it is necessary to observe or measure a sample having a shape having a nearly vertical side wall. However, the conventional scanning probe microscope can only detect the interaction between the probe portion and the sample immediately below the probe portion, so that it has been difficult to precisely observe the vertical shape. If the sample is tilted, the force between the vertical side wall of the sample and the probe can be detected, but precise observation of a fine vertical shape is difficult.

In order to solve this problem, a probe having a laterally sharp edge is used, and the interaction between such a probe and the side wall of the sample is detected to determine the shape of the side wall of the sample. Atomic force microscope has been reported (Yves M)
artin and H.S. Kumar Wickram
asinghe, Appl. Phys. Lett. 64
(19), 9 May 1994, "Method f
or imagingsidewalls by at
In such an atomic force microscope, the cantilever slowly reciprocates in the horizontal direction while exciting the cantilever at a frequency close to the resonance frequency, and acts on the probe portion. By detecting the change of the resonance frequency of the cantilever caused by the change of the remote force, the force of the interaction between the probe part and the sample side wall beside the probe part is detected, and the vertical side wall is provided. The observation of the sample was enabled.

[0006]

Since the degree of integration of semiconductors has been improving year by year, and the width of patterns has been getting narrower accordingly, fine irregularities which are vertical and have a high aspect ratio, for example, a width of about 200 nm. It has become necessary to observe a sample having a groove or a trench.

However, in the conventional atomic force microscope using the above-described probe having a laterally sharp edge, it is difficult to reduce the diameter of the tip of the probe. It was difficult to insert into the fine grooves of the sample. Further, even if the probe part can be inserted into the fine groove of the semiconductor sample, there is not enough space to reciprocate the probe part in the lateral direction for detecting the force. For this reason, it has been difficult for a conventional atomic force microscope to accurately observe a concave shape such as a fine groove of a semiconductor sample, even though a convex sample can be observed. This is not limited to the atomic force microscope, but also applies to other scanning probe microscopes such as a scanning capacitance microscope, a scanning electrostatic force microscope, and a scanning magnetic force microscope.

It has also been reported that carbon nanotubes are formed at the tip of a probe (Nature. V).
ol384.111 November 1996),
It has been difficult to stably produce the probe. Further, the rigidity of the lever portion is high with respect to the carbon nanotube as the probe portion, and the force acting on the tip of the probe portion is not transmitted well to the cantilever, so that there are many practical problems.

An object of the present invention is to provide a probe for a scanning probe microscope which can be inserted into a fine groove or the like of a semiconductor sample and a method for manufacturing the probe in view of the problems in the conventional apparatus. To provide.

Another object of the present invention is to increase the interaction force between a probe of a scanning probe microscope which can be inserted into a fine groove or the like of a semiconductor sample and a nearly vertical side wall of the sample. It is to provide a method of detecting with sensitivity.

Still another object of the present invention is to provide a probe of a scanning probe microscope capable of precisely observing or measuring a sample having a vertical, high aspect ratio, and fine irregularities, and a force acting on the probe. It is to provide a detection method.

[0012]

In order to achieve the above object, according to the first aspect of the present invention, a probe of a scanning probe microscope includes a support portion, a probe portion, the support portion, and the probe. A detecting unit provided between the probe unit and the probe unit for detecting an interaction between the probe unit and the sample, wherein the detecting unit and the probe unit are formed substantially on the same axis. Since the detecting section and the probe section are formed on the same axis, there is little spatial restriction, and the probe can be easily inserted into a fine groove or the like of the semiconductor sample.

[0013] According to the second aspect of the present invention, in the probe of the scanning probe microscope according to the first aspect, the detecting section is configured to have a light reflecting section for reflecting light.
This makes it possible to detect the interaction force generated between the probe section and the sample with high sensitivity using the optical lever method.

According to a third aspect of the present invention, in the probe of the scanning probe microscope according to the first aspect, the detection unit has at least one coil pattern. This allows the probe to be placed in a magnetic field and an alternating current to flow through the coil pattern to excite the probe into a torsional resonance state, or to detect the induced current flowing through the coil pattern to detect the vibration state of the detector. can do. The probe is excited to a torsional resonance state, and the change in the vibration state of the detector due to the force acting on the probe can be detected. It becomes possible to detect with high sensitivity.

According to a fourth aspect of the present invention, in the probe of the scanning probe microscope according to the first aspect, the detection section is configured to have a piezoelectric thin film. This allows
The interaction force generated between the probe section and the sample can be detected with high sensitivity.

According to a fifth aspect of the present invention, in the probe of the scanning probe microscope according to the first aspect, the detection section has a resistor. This makes it possible to detect the interaction force generated between the probe section and the sample with high sensitivity.

According to the sixth aspect of the present invention, in the probe of the scanning probe microscope according to the first aspect, the support portion, the detection portion, and the probe portion are formed substantially on the same plane. It is configured to be. Accordingly, it is possible to provide a probe of a scanning probe microscope in which the spatial restriction is less and the detection of the interaction between the probe and the sample in the detection unit is easier.

Further, according to the present invention, the probe of the scanning probe microscope comprises a support, a probe portion, and a cantilever connecting the support and the probe portion, and The cantilever is provided with a mass portion for causing the needle portion to resonate around the central axis of the probe portion. Accordingly, if a force acts on the probe when the probe is excited to the torsional resonance state, the moment of inertia of the probe greatly changes due to the presence of the mass. By detecting the change in the moment of inertia, it is possible to detect the interaction force generated between the probe section and the sample with high sensitivity without contact.

According to the invention of claim 8, the probe of the scanning probe microscope comprises a support, a probe portion, and a cantilever connecting the support and the probe. A light reflecting portion for detecting displacement of the probe is provided so as to be flush with the probe, and the probe is formed to have a width of 200 nm or less and a length of 1 μm or more. Accordingly, a probe of a scanning probe microscope which can be inserted into a fine groove or the like of a semiconductor sample with little spatial restriction is provided.

According to the ninth aspect of the present invention, the probe of the scanning probe microscope includes a support, a vibration excitation unit connected to the support, a vibration unit connected to the vibration excitation unit, and a vibration unit connected to the vibration excitation unit. And a probe section narrower than the vibrating section. The vibration exciting section, the vibrating section, and the probe section are formed substantially on the same axis. Accordingly, a probe of a scanning probe microscope which can be inserted into a fine groove or the like of a semiconductor sample with little spatial restriction is provided. Also, by exciting the probe to a torsional resonance state and detecting a change in the vibration state of the vibrating portion due to the force acting on the probe portion, the interaction force generated between the probe portion and the sample can be reduced. The contact can be detected with high sensitivity. Since the probe is provided with the vibration excitation section, there is no need to provide a vibration mechanism for the probe outside, and the system can be simplified.

According to a tenth aspect of the present invention, in the probe of the scanning probe microscope according to the ninth aspect, the vibration excitation part, the vibration part, and the probe part project from the support. It consists of. This makes it possible to provide a scanning probe microscope probe that is easier to manufacture.

According to the eleventh aspect of the present invention, in the probe of the scanning probe microscope according to any one of the ninth and tenth aspects, the vibration excitation section has a driving coil pattern or a driving piezoelectric thin film. It is configured as follows. Accordingly, the probe can be vibrated accurately without providing a probe vibrating mechanism outside.

According to a twelfth aspect of the present invention, in the method for manufacturing a probe of a scanning probe microscope, the steps of: preparing a semiconductor substrate; forming a first layer on the semiconductor substrate; Forming a second layer on the first layer, patterning the second layer to form a first portion, a second portion, and a third portion.
Forming a patterned second layer having a portion, a fourth portion, and a fifth portion, wherein
Portion has a tapered shape toward the second portion, and the second portion has a tapered shape toward the first portion, whereby the first portion and the second portion are tapered.
Are in contact with each other to form a narrowed portion, and the third
A portion contacting the second portion and having a wider width than the second portion, the fourth portion contacting the third portion and having a smaller width than the third portion, and The fifth
Having a width in contact with the fourth portion and having a greater width than the fourth portion, and etching the first layer using the patterned second layer as a mask;
Removing the patterned second layer; and removing at least a portion of the semiconductor substrate. This makes it possible to easily and accurately manufacture a probe of a scanning probe microscope which has little spatial restriction and can be easily inserted into a fine groove or the like of a semiconductor sample.

According to a thirteenth aspect of the present invention, in the method for manufacturing a probe of a scanning probe microscope, a step of preparing a semiconductor substrate; a step of forming a first layer on the semiconductor substrate; Forming a second layer on the second layer, patterning the second layer to form an opening, forming a metal layer on the patterned second layer and the opening Removing said patterned second layer together with said metal layer on said patterned second layer, thereby removing said first layer at a position corresponding to said opening and said first layer.
Forming a metal part comprising the metal layer on the layer of
Forming a third layer on the first layer and the metal portion, patterning the third layer to form a first portion, a second portion, a third portion, a fourth portion, and Forming a patterned third layer having a fifth portion, wherein the first portion has a tapered shape toward the second portion, and wherein the second portion has A tapered shape toward the first portion, whereby the first and second portions meet to form a narrowed portion, and the third portion covers the metal portion; While contacting the second portion and having a wider width than the second portion;
The fourth portion is in contact with the third portion and has a smaller width than the third portion, and the fifth portion is in contact with the fourth portion and has a wider width than the fourth portion. Having, etching the first layer using the patterned third layer as a mask, removing the patterned third layer, removing at least a portion of the semiconductor substrate. Removing step. This makes it possible to easily and accurately manufacture a probe of a scanning probe microscope which has little spatial restriction and can be easily inserted into a fine groove or the like of a semiconductor sample.

According to a fourteenth aspect of the present invention, in the method for manufacturing a probe of a scanning probe microscope according to any one of the twelfth and thirteenth aspects, after the step of preparing a semiconductor substrate and the semiconductor substrate, Forming a slope and a flat portion in the semiconductor substrate by etching the semiconductor substrate before forming the first layer thereon, wherein the first portion and the second portion are at least formed. Partially on an inclined portion of the semiconductor substrate, the third portion, the fourth portion, and the fifth portion are on a flat portion of the semiconductor substrate, and the first portion and the second portion. The reduced-width portion where the portion is in contact is located on the inclined portion of the semiconductor substrate. As a result, the tip portion of the probe is formed so as to protrude laterally or obliquely, so that the probe of the scanning probe microscope that can observe the shape of the side wall such as the groove of the semiconductor sample more easily and easily is provided. It can be produced accurately.

According to a fifteenth aspect of the present invention, in the method for manufacturing a probe of a scanning probe microscope according to any one of the twelfth to fifteenth aspects, the semiconductor substrate is a silicon substrate, and The first layer is configured to be either a silicon nitride layer or a silicon oxide layer. Thereby, the probe of the scanning probe microscope can be manufactured more easily and accurately.

According to a sixteenth aspect of the present invention, in the method for detecting a force of the scanning probe microscope, the probe is caused to perform a predetermined reciprocating rotation about the center axis of the probe, and the reciprocating rotation is performed. It is configured to detect a force acting on the probe by detecting a change in. As a result, the force acting on the probe can be detected with high sensitivity without contact.
There are few spatial constraints.

In the invention according to claim 17, the force detection method of the scanning probe microscope is characterized in that the support comprises: a support, a support protruding from the support and formed substantially on the same axis;
A detection unit that is connected to the support unit and is wider than the support unit;
And a force detection method of a scanning probe microscope using a probe having a probe portion having a narrower width than the detection portion and connected to the detection portion, wherein torsional resonance is excited in the detection portion,
Further, it is configured to detect a force acting on the probe unit by detecting a change in the moment of inertia of the detection unit. Thereby, the force acting on the probe can be detected in a non-contact manner with high sensitivity. In addition, there are few spatial restrictions.

Further, in the invention according to claim 18, the force detection method of the scanning probe microscope comprises a support, and a support portion projecting from the support and formed substantially on the same axis;
A detection unit that is connected to the support unit and is wider than the support unit;
And a force detection method of a scanning probe microscope using a probe having a probe portion having a narrower width than the detection portion and connected to the detection portion, wherein torsional resonance is excited in the detection portion,
Further, a force acting on the probe unit is detected by detecting a change in the amplitude of the detection unit in the twisting direction. Thus, the force acting on the probe can be detected easily and with high sensitivity without contact. In addition, there are few spatial restrictions.

Further, in the invention according to claim 19, the force detecting method of the scanning probe microscope comprises: a support; and a support protruding from the support and formed substantially on the same axis;
A detection unit that is connected to the support unit and is wider than the support unit;
And a force detection method of a scanning probe microscope using a probe having a probe portion having a narrower width than the detection portion and connected to the detection portion, wherein torsional resonance is excited in the detection portion,
Further, it is configured to detect a force acting on the probe section by detecting a frequency change of the torsional resonance of the detection section. Thus, the force acting on the probe can be detected easily and with high sensitivity without contact. In addition, there are few spatial restrictions.

According to a twentieth aspect of the present invention, in the method for detecting a force of the scanning probe microscope according to any one of the seventeenth to nineteenth aspects, the support is vibrated by a vibrator. It is configured to excite torsional resonance. Thereby, torsional resonance can be excited accurately.

According to a twenty-first aspect of the present invention, in the method for detecting a force of a scanning probe microscope according to any one of the seventeenth to nineteenth aspects, the supporting portion includes a driving piezoelectric thin film or a driving coil pattern. Is provided, and the torsional resonance is excited by passing an alternating current through the driving piezoelectric thin film or by placing the probe in an external magnetic field and passing an alternating current through the driving coil pattern. It is configured to Since the probe is provided with the vibration excitation section, there is no need to provide a vibration mechanism for the probe outside, and the system can be simplified.

[0033]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a probe and a force detecting method for a scanning probe microscope according to the present invention will be described with reference to the drawings. FIG. 1 is a perspective view conceptually showing a probe of the scanning probe microscope according to the first embodiment of the present invention. In FIG. 1 and subsequent figures, the probe is partially arbitrarily expanded and contracted at a ratio different from the actual ratio for easy understanding. This ratio of expansion and contraction is not common to each drawing.

The probe of the scanning probe microscope shown in FIG. 1 includes a support 1, a support or cantilever 2, a detector 3, and a probe 4. The cantilever part 2, the detection part 3, and the probe part 4 are formed substantially continuously on the same axis, and also formed continuously with the support 1.

The probe portion 4 has a width of preferably 200 nm or less, for example, about 100 to 200 nm, and a length of preferably 1 μm or more, for example, about 3 μm.
Since the probe part 4 is thin and long, it can be easily inserted into the trench 5 or the groove of the semiconductor sample. The tip portion of the probe 4 preferably projects in the horizontal or oblique direction as shown in FIG. 1, but may be linear. It is more preferable that the tip of the probe part 4 is sharpened.

The detecting section 3 has, for example, a side (long side) of 50 μm.
The cantilever 2 and the probe 4 are formed on substantially the same plane. Further, the detection unit 3 has a light reflection surface that reflects light, that is, a mirror portion. The cantilever 2 bends when a force acts on the probe 4, and connects and supports the probe 4 and the detector 3 to the support 1. Support 1
Is, for example, a flat plate having a size on the order of millimeters.

The probe according to the present embodiment has a thin and long probe portion 4, and further includes a cantilever portion 2, a detection portion 3, and a probe portion 4.
Are formed on the same axis, and there are few spatial restrictions. Therefore, the probe portion can be inserted into the fine groove, and the probe can be scanned over a sample having fine irregularities.

Next, a method for manufacturing a probe of a scanning probe microscope having such a configuration will be described. FIG. 2 shows a probe section 4 of the probe of the scanning probe microscope shown in FIG.
FIG. 7 is a schematic view showing a manufacturing process when the tip portion of is straight.

As the semiconductor substrate 11, for example, a thickness of about 25
Using a silicon single crystal substrate having a 0 μm (100) plane orientation, silicon nitride films 12 and 13 having a thickness of, for example, about 0.1 μm are formed on both surfaces of the semiconductor substrate 11 by LP-CVD (low pressure CVD) or the like ( FIG. 2 (a)).

A resist film 14 is applied on the silicon nitride film 12 on the substrate 11, and a rectangular opening corresponding to a mirror portion to be described later is formed in the resist film 14 by lithography. A thin layer of nickel chromium is vapor-deposited thereon, and a gold layer 15 (portion indicated by oblique lines in FIG. 2B) is vapor-deposited on the entire surface (FIG. 2B). If nickel chromium is used as a base between the silicon nitride film 12 and the gold layer 15, the resistance of the subsequent gold layer 15 is increased, and
Peeling etc. will not occur. Unnecessary portions of the gold layer 15 are removed together with the resist film 14 using a lift-off method, and a gold mirror portion 16 (FIG.
Patterning is performed on the portion shown by oblique lines in FIG. 2C (FIG. 2C). The mirror part 16 corresponds to the light reflecting surface or the mirror part of the detection part 3 of the probe.

Silicon nitride films 12 and 13 and mirror portion 1
6 is coated with a resist film 17 and, using a lithography method, according to the predetermined shape of the support 1, the cantilever 2, the detector 3, the probe 4, and the thin film 18 facing the probe 4. And patterning. Here, the resist film 17 in the portion corresponding to the probe portion 4 and the resist film 17 in the portion corresponding to the thin film portion 18 are separated so that the tip portion of the probe portion 4 is separated from the thin film portion 18 by a later etching process. 2 has a narrow constricted portion 19 almost at the very end of the resolution of the lithography method, that is, about the wavelength of light (FIG. 2).
(D)).

Thereafter, unnecessary portions of the silicon nitride films 12 and 13 on the upper and lower surfaces of the substrate 11 are removed by isotropic etching such as dry etching (FIG. 2).
(E)). At this time, since the silicon nitride film 12 is isotropically etched, the silicon nitride film 12 protected by the resist film 17 is under-etched. Due to this under-etching, the portion of the silicon nitride film 12 where the probe 4 is formed becomes narrower than the portion of the resist film 17 corresponding to the probe 4.

FIG. 2F is a schematic enlarged plan view showing a state in which the silicon nitride film 12 in a peripheral region of a portion corresponding to the probe part 4 is under-etched. In FIG. 2F, the silicon nitride film 12 under the resist film 17 is shown by a dotted line to show under-etching under the resist film 17. As shown in FIG. 2F, the portion of the silicon nitride film 12 where the probe 4 is formed by the under-etching is thinner than the shape of the resist film 17. The silicon nitride film 12 is separated into a portion below the thin film portion 18 of the silicon nitride film 12 and a portion of the silicon nitride film 12 where the probe 4 is formed by underetching under the constricted portion 19. For this reason, the tip portion of the silicon nitride film 12 where the probe portion 4 is formed becomes sharp and thin and extremely sharp.

Finally, the resist film 17 is removed and impregnated with an etching solution for silicon such as an aqueous solution of potassium hydroxide (KOH) or an aqueous solution of tetramethylammonium hydroxide (TMAH).
Using the mask 3 as a mask, the exposed portion of the substrate 11 is removed by anisotropic etching (FIGS. 2G and 2H). Thus, the probe of the scanning probe microscope made of the silicon nitride film and the gold can be manufactured at a low cost collectively by using the semiconductor manufacturing technology.

The process of manufacturing a probe of a scanning probe microscope made of a silicon nitride film and gold by forming a silicon nitride film on a silicon substrate has been described. For example, by forming a silicon oxide film on a silicon substrate, A probe for a scanning probe microscope made of a silicon oxide film and gold can also be manufactured.

In the probe of the scanning probe microscope manufactured by such a manufacturing method, the probe portion 4 is linear, but the tip portion of the probe portion 4 is laterally or obliquely formed by the following method. The probe of the scanning probe microscope protruding in the direction can be formed.

FIG. 3 is a schematic view showing a manufacturing process in the case where the tip of the probe portion 4 of the probe of the scanning probe microscope shown in FIG. 1 is projected in the horizontal or oblique direction. In FIG. 3, components corresponding to the components in FIG. 2 are denoted by the same reference numerals.

As the semiconductor substrate 11, for example, a thickness of about 25
Using a silicon single crystal substrate having a 0 μm (100) plane orientation, silicon nitride films 12 and 13 having a thickness of, for example, about 0.1 μm are formed on both surfaces of a semiconductor substrate 11 by LP-CVD (low pressure CVD) or the like. The silicon nitride film 12 is patterned using a lithography method and a dry etching method, and an opening 20 for exposing the substrate 11 is formed at a predetermined position of the silicon nitride film 12 (FIG. 3A).

Next, an aqueous solution of potassium hydroxide (KOH) or tetramethylammonium hydroxide (T
MAH) Impregnated with an etching solution for silicon such as an aqueous solution, and anisotropically etching the portion exposed from the opening 20 of the substrate 11 using the silicon nitride films 12 and 13 as a mask to form an inclined surface 22 continuous with the opening 20. A groove 21 having a depth of about 2 μm is formed in the substrate 11 (FIG. 3B). Since a silicon single crystal having a (100) plane orientation is used for the substrate 11, the inclined surface 22 is a (111) surface of the silicon single crystal, and the inclined surface 22 is located on the bottom surface of the groove 21, that is, the surface of the substrate 11. The angle formed is about 54.74 °. As will be described later, this angle is determined by the tip portion of the probe, the probe portion 4 and the detection portion 3.
And it becomes the angle which inclines and protrudes with respect to the cantilever part.

Next, silicon nitride films 23 and 24 having a thickness of, for example, about 0.1 μm are formed on both surfaces of the semiconductor substrate 11 again by the LP-CVD method or the like, and the lift-off method or the like is used as in the case of FIG. Mirror part 1 on silicon nitride film 23
6 (portion indicated by oblique lines in FIG. 3C) is patterned (FIG. 3C).

Silicon nitride films 23 and 24 and mirror part 1
6, a support 1, a cantilever 2, a detector 3, and a probe 4 using a lithography method.
The resist film is patterned according to a predetermined shape of the thin film portion facing the probe portion 4. Here, the reason why the thin film portion facing the probe portion 4 is used is to make the tip portion of the probe portion 4 sharp and thin similarly to the case of FIG. Further, a narrow portion between the resist film portion corresponding to the probe portion 4 and the resist film portion corresponding to the thin film portion opposed thereto is formed on the slope 22.

Thereafter, unnecessary portions of the silicon nitride films 12, 13, 23 and 24 on the upper and lower surfaces of the substrate are removed by isotropic etching such as dry etching (FIG. 3D). At this time, since the silicon nitride film 23 is isotropically etched, the silicon nitride film 23 protected by the resist film is under-etched. Therefore, as in the case of FIG. 2, the portion of the silicon nitride film 23 where the probe 4 is formed is narrower than the portion corresponding to the probe 4 of the resist film, and the tip is extremely sharpened. Is done. Further, the tip portion of the portion of the silicon nitride film 23 where the probe portion 4 is formed is formed so as to protrude laterally or obliquely.

Finally, the resist film is removed, and the substrate is immersed in an etching solution for silicon such as an aqueous solution of potassium hydroxide (KOH) or an aqueous solution of tetramethylammonium hydroxide (TMAH). The exposed portion 11 is removed by anisotropic etching. This makes it possible to obtain a probe of a scanning probe microscope which is made of a silicon nitride film and gold and whose tip protrudes laterally or obliquely (FIGS. 3E and 3F).

Next, a method for detecting an interaction force acting between the probe and the sample using the probe of the scanning probe microscope of the present embodiment will be described. FIG. 4 is a perspective view conceptually showing a method of detecting a force acting between the probe and the sample using the probe of the scanning probe microscope of the present embodiment.

In the probe of the scanning probe microscope of the present embodiment, since the probe portion 4 is thin and long, the trench 5 of the semiconductor sample is formed.
And can be inserted into the groove. When an interaction force acts between the tip portion or the side portion of the probe portion 4 and the inner wall such as the side wall or the bottom surface of the trench 5 of the semiconductor sample, the cantilever portion 2 or the like bends accordingly, and the detecting portion 3 has high sensitivity.
Light reflecting surface tilts. The change in the angle of the light reflecting surface of the detection unit 3 can be detected by an optical lever method or the like. For example, the light reflecting surface of the detecting section 3 is irradiated with laser light by a laser 6 or the like, and the reflected light is split into a split photodiode
, It is possible to detect a change in the angle of the light reflecting surface of the detection unit 3 with high sensitivity. Split type photodiode 7
Although a four-division photodiode is used in the above, a two-division photodiode divided into right and left may be used.

The force acting on the side surface of the probe 4 reflects the interaction between the semiconductor sample and the side wall of the trench 5, and the force acting on the tip of the probe 4 is It reflects the interaction with the bottom. Therefore, by detecting the change in the angle of the light reflecting surface of the detection unit 3 that is deflected by the force acting on the probe 4, the interaction force between the probe 4 and the inner wall of the trench 5 of the semiconductor sample is detected. Can be detected, and the shape of the inner wall of the trench 5 of the semiconductor sample can be imaged and observed. Further, if the tip portion of the probe portion 4 protrudes laterally or obliquely, it is possible to detect the interaction force between the semiconductor sample and the side wall of the trench 5 with higher sensitivity.

If the probe 4 is thin and long, the probe 4
The rigidity of the probe becomes low, and the interaction force between the probe portion 4 and the sample is not transmitted to the cantilever portion. However, in the probe of the present embodiment, the light reflecting surface of the detection portion 3 is continuous with the probe portion. Because of this, when an interaction force acts between the probe part 4 and the side wall of the sample, the angle of the light reflecting surface changes with high efficiency. Therefore, the force acting on the soft probe portion 4 can be detected with high sensitivity, and the inner wall of the trench 5 of the semiconductor sample can be imaged.

Next, the overall configuration of the scanning probe microscope using the probe shown in FIG. 1 will be described. FIG.
FIG. 6 is an overall configuration diagram of a scanning probe microscope using the probe shown in FIG. 1, and FIG. 6 is a block diagram schematically showing an operation.

The support 1 of the probe is held by the clip 30
It is held on the free end side of a Z-axis direction driving PZT element 31 which is a piezoelectric element. PZT element 31 for driving in Z-axis direction
Is fixed to the block 32. The free ends of the PZT element 33 for driving in the X-axis direction and the PZT element 34 for driving in the Y-axis direction, which are piezoelectric elements, are both fixed to the block 32, and the fixed ends are fixed to the frame 35. The frame 35 is supported by three micrometers 36. The positions of the semiconductor laser 6, the four-division photodiode 7, and the mirror 37 are adjusted and fixed to the block 32. The light emitted from the semiconductor laser 6 and the output from the four-division photodiode 7 are processed by an electric circuit 38 provided on the frame 35. A vibrator 39 is provided on the lower surface of the clip 30 for observation in a non-contact mode.

The scanning probe microscope having such a configuration performs imaging of the surface shape of the sample 5 by the following operation. Digital signal processor (DSP) 40
Is converted into a voltage by a DA conversion circuit 41 and boosted by a high voltage amplifier 42, and thereafter, the PZT elements 33 and 34 for driving the probe are driven.
Is applied to As a result, the probe moves in the plane direction of the sample, and the relative distance between the probe portion 4 of the probe and the sample 5 changes. Therefore, the interaction force between the sample 5 and the probe unit 4 changes, the detecting unit 3 of the probe bends, and the angle of the light reflecting surface of the detecting unit 3 changes.

On the other hand, the mirror 37 is driven by the semiconductor laser 6.
The light applied to the light reflecting surface of the detection unit 3 via the light is reflected and detected by the four-division photodiode 7. A signal corresponding to a change in the angle of the light reflecting surface of the detection unit 3 detected by the four-division photodiode 7, that is, a change in the interaction force between the sample 5 and the probe unit 4 of the probe is output to the preamplifier 43.
, And is digitized by the AD converter 45 through the lock-in amplifier 44 and input to the DSP 40.

In the DSP 40, servo calculation for keeping the relative distance between the sample and the probe 4 constant in accordance with the change in the interaction force between the sample 5 and the probe 4 of the probe is performed. Then, the feedback signal is applied to the Z-axis direction driving PZT 41 via the DA 41 and the high voltage amplifier 42. This feedback signal reflects the surface shape of the sample 5, and the personal computer 47 connected to the DSP 40
Is displayed on the display and the data is stored.

A method of imaging a sample shape by scanning a probe on a sample and detecting a force acting between the probe and the sample includes a contact mode in which the probe is brought into contact with the sample. There is a non-contact mode (non-contact mode) in which the probe is not brought into contact with the sample. By using the probe of the present embodiment, in the non-contact mode, the force acting between the probe and the sample can be detected by the following method, and the shape of the sample can be imaged.

FIG. 7 is a conceptual diagram showing a method for detecting the force acting between the probe and the sample in a non-contact manner. In the probe of the present embodiment, resonance vibration of reciprocating rotational movement around the central axis 9 of the cantilever portion 2, the detection portion 3, and the probe portion 4, that is, torsional resonance is excited. This torsional resonance is
For example, it is excited by vibrating the support 1 of the probe with a vibrator at a frequency equal to the resonance frequency of the probe (FIG. 7).
(A)).

The probe 4 is inserted into the trench 5 of the semiconductor sample in a state where the torsional resonance is excited. Probe part 4
If a force such as Van der Waals force 8 acts on the tip or side surface of the probe, the probe 4 is pulled in the direction of the force (FIG. 7B).

In this case, since the detecting section 3 and the probe section 4 deviate from the rotating shaft 9 of the resonance vibration, the moment of inertia around the rotating shaft 9 increases sharply. When the moment of inertia increases, the resonance frequency in the torsional direction (the direction of rotation about the rotating shaft 9) decreases, so that the probe deviates from the torsional resonance state, and the amplitude of the detector 3 in the torsional direction decreases. The change in the amplitude of the detection unit 3 is detected by an optical lever method or the like. Therefore, the resonance vibration of the reciprocating rotary motion is excited on the probe,
By detecting a change in the amplitude in the torsional direction of the detector 3 of the probe, a force acting between the probe 4 and the sample can be detected, and the shape of the sample can be imaged.

In the probe, the cantilever portion 2, the detection portion 3, and the probe portion 4 are formed on the same axis and excite reciprocating rotational movement around this axis, that is, torsional vibration. There are few mechanical and spatial restrictions on scanning the sample on the sample. Therefore, the probe portion 4 can be easily inserted into a narrow groove such as a semiconductor trench while exciting the torsional vibration to the probe, and the mutual contact between the probe portion 4 and the sample can be made in a non-contact manner. The effect can be detected.

Instead of the change in the amplitude of the detecting section 3 in the torsional direction, a change in the resonance frequency of the detecting section 3 in the torsional direction due to an increase in the moment of inertia may be detected by, for example, a frequency modulation method. If a force acts on the probe part 4, the resonance frequency also changes due to an increase in the moment of inertia. Therefore, the force acting between the probe part 4 and the sample can be detected by detecting the change in the resonance frequency. .

Next, the sensitivity of this force detection method will be described. First, in order to calculate a change in the moment of inertia of the probe, the detection unit 3 occupying most of the moment of inertia is calculated using a typical model. FIG. 8 is a conceptual diagram showing a state in which a square object 48 having a surface density ρ and a diagonal length a is inclined by an angle θ from an axis 49 in a direction that bisects the object 48. This corresponds to the detection unit 3. The moment of inertia I of the object 48 at an angle θ from the axis 49 with respect to the axis 49 is expressed by the following equation.

I (θ) = a ⁴ ρ / 48 + 7a ⁴ ρsin
² (θ) / 48. Of these, the increase in the moment of inertia due to the object 48 being inclined by the angle θ is the portion expressed by the second term in the preceding equation.

In general, in the frequency detection method used in the non-contact mode of the conventional scanning microscope, when the torsional resonance frequency of the probe is about 100 kHz,
The deviation of the resonance frequency can be sufficiently detected with a sensitivity of 1 Hz. Therefore, the torsional resonance frequency of the probe is set to 100 kHz.
Assuming z, the deviation of the object 48 from the rotation axis 49 when the torsional resonance frequency changes by 1 Hz is defined as θ ′. Since the resonance frequency is proportional to the root (half) of the moment of inertia,

## EQU2 ## 100 kHz: 1 Hz = (a ⁴ ρ / 48) ^1/2 : (7a ⁴ ρsin ² (θ ′) / 48) ^1/2 holds. In this case, θ ′ is about 4 μradian.

The length from the cantilever portion 2 of the probe to 5
When 0 μm (that is, a is about 50 μm), the deviation of the tip of the probe from the rotation axis when the probe is rotated by 4 μradian is about 0.2 nm. Therefore, the method of exciting the torsional resonance to the probe of the present embodiment and detecting the force acting between the probe and the sample, that is, the force acting between the probe portion 4 of the probe and the sample, is as follows. The tip of the probe is approx.
This indicates that a force moving by 2 nm can be roughly detected, indicating that the device has high force detection sensitivity.

Thus, torsional resonance is excited in the probe,
The operation of the scanning probe microscope when imaging the sample surface shape using the method of detecting the force acting between the probe and the sample will be described with reference to FIGS.

Digital signal processor (DSP) 4
The oscillating circuit 46 controlled by 0 generates a sine wave that is substantially equal to the torsional resonance frequency of the probe.
To enter. As a result, the vibrator 39 is attached to the support 1
Vibrates to cause torsional resonance in the cantilever portion 2 of the probe.

The probe drive signal generated by the DSP 40 is converted into a voltage by the DA conversion circuit 41, boosted by the high voltage amplifier 42, and then converted to a P for driving the probe.
It is applied to ZT elements 33 and 34. by this,
The probe moves in the plane direction of the sample, and the relative distance between the probe portion 4 of the probe and the sample 5 changes. Therefore, the interaction force between the sample 5 and the probe portion 4 of the probe changes, the torsional resonance frequency of the probe changes, and the amplitude of the torsional resonance of the probe also changes.

On the other hand, the mirror 37 is
The light emitted to the light reflecting surface of the detection unit 3 of the probe through
The light is reflected and detected by the four-division photodiode 7. A signal corresponding to a change in the amplitude of the torsional resonance of the detection unit 3 of the probe detected by the four-division photodiode 7, that is, a change in the interaction force between the sample 5 and the probe unit 4 of the probe is:
The signal is amplified by the preamplifier 43 and input to the lock-in amplifier 44. The lock-in amplifier 44 amplifies and outputs only a frequency component substantially equal to the signal from the oscillation circuit 46. The signal corresponding to the amplitude of the torsional vibration of the probe amplified by the lock-in amplifier 44 is digitized by the AD converter 45 and input to the DSP 40.

In the DSP 40, a servo calculation for keeping the relative distance between the sample 5 and the probe 4 constant in accordance with the change in the interaction force between the sample 5 and the probe 4 of the probe. Is performed, and the feedback signal is applied to the PZT 31 for driving in the Z-axis direction. This feedback signal reflects the surface shape of the sample 5, is displayed on a display by a personal computer 47 connected to the DSP 40, and the data is stored.

In the method of detecting the force acting between the probe and the sample by exciting the torsional resonance in the probe, the probe is scanned with the probe inclined with respect to the sample surface. Shapes can also be imaged. FIG. 9 shows a conceptual diagram of the force detection method in this case.

The surface shape of the sample 50 is not a shape having a deep groove such as a trench. When the probe is held obliquely with respect to the surface of the sample 50 and torsional resonance is excited in the probe to bring the probe 4 of the probe close to the surface of the sample 50, the probe 4
An interaction force acts between the probe and the sample 50, and the probe deviates from the rotation axis of the twist. As a result, the moment of inertia of the probe increases, and the amplitude of the torsional vibration of the probe decreases. As described above, the change in the amplitude of the torsional vibration of the probe is detected by detecting the reflected light of the laser beam emitted from the laser 6 at the mirror portion of the detection unit 3 by the four-division photodiode 7. The three-dimensional shape of the surface of the sample 50 can be imaged.

FIG. 10 is a perspective view conceptually showing a probe of a scanning probe microscope according to the second embodiment of the present invention. In the probe of the present embodiment, as a method of exciting torsional resonance, Lorentz force, which is an electromagnetic force, is used instead of the above-described mechanical excitation by the vibration of the vibrator.

The probe shown in FIG. 10 includes a wiring 51 made of a metal such as gold provided over the support 1, the cantilever 2 and the detection section 3, and a metal provided on the support 1. Except for having two pads 52 and 53, it has a configuration substantially similar to that of the probe of FIG. The wiring 51 forms a coil in the detection unit 3, and both ends of the wiring 51 are connected to two pads 52 in the support 1.
And 53. The light reflecting surface or the mirror portion of the detection unit 3 is formed, for example, with a gap in a coil formed by the wiring 51 so as not to contact the wiring 51.

By holding such a probe in a magnetic field and passing a current between the wiring 51, that is, the pads 52 and 53, a Lorentz force can be generated in the probe.
By changing the direction of the flowing current at a frequency equal to the torsional resonance frequency of the probe, the probe can be excited or excited to a torsional resonance state. Since no external vibration mechanism such as a vibrator is required, the system can be simplified accordingly.

A probe having wiring for generating Lorentz force as shown in FIG. 10 can be manufactured by a method schematically shown in FIG. In FIG. 11, the same reference numerals are given to the components corresponding to the respective components in FIG.

In a method similar to that shown in FIG. 3, silicon nitride films 12 and 13 are formed on both surfaces of semiconductor substrate 11, and silicon nitride film 12 is patterned, so that substrate 11 Is formed (FIG. 11A). Further, a groove 21 continuous with the opening 20 and having an inclined surface 22 is formed in the substrate 11 in the same manner as in FIG. 3 (FIG. 11B).

Next, as in the case of FIG.
For example, a thickness of about 0.
1 μm silicon nitride films 23 and 24 are formed, and a gold layer (a portion shown by oblique lines in FIG. 11) is patterned on the silicon nitride film 23 using a lift-off method or the like. The wiring 51 and the pads 52 and 53 are also patterned together with the mirror portion 16 (FIG. 11C).

In the same manner as in FIG. 3, a resist film is applied on the silicon nitride films 23 and 24 and the gold layer corresponding to the mirror portion 16 and the wiring 51 and the like. Cantilever part 2, detection part 3, probe part 4
The resist film is patterned according to a predetermined shape of the thin film portion facing the probe portion 4. Thereafter, as in the case of FIG. 3, the silicon nitride films 12, 1 on the upper and lower surfaces of the substrate are formed.
Unnecessary portions 3, 23 and 24 are removed by isotropic etching (FIG. 11D).

Finally, in the same manner as in FIG. 3, the resist film is removed, and the exposed portion of the substrate 11 is removed by anisotropic etching using the silicon nitride films 23 and 24 as a mask. As a result, a probe having the gold wiring 51 and the pads 52 and 53 as shown in FIG. 9 can be obtained (FIGS. 11E and 11F).

FIG. 12 is a conceptual front view of a probe of a scanning probe microscope according to the third embodiment of the present invention. The probe of the scanning probe microscope shown in FIG. 12 includes a support 61, a vibration excitation section 62, a vibration section 63, and a probe section 64 protruding from the support.

Support 61, vibrating section 63, and probe section 6
Numeral 4 substantially corresponds to the support 1, the detecting section 3 and the probe section 4 in the probe of FIG. 1, respectively. In the probe of the present embodiment, the vibration exciting section 62 is provided on the support section or the cantilever section. Is provided. The vibration exciting part 62 and the vibration part 63 are connected by a connecting torsion part 65 having a small torsional rigidity, that is, a small width. In addition, the vibration excitation unit 6
2 and the vibrating part 63 are of a flat plate shape.

The vibration excitation section 62, the vibration section 63, and the probe section 64 are formed substantially continuously on the same axis on the same plane, and are also formed continuously with the support 61. Like the probe of FIG. 1, the probe portion 64 has a width of 100 to 2 for example.
It has a size of about 00 nm and a length of about 3 μm. The tip portion of the probe portion 104 preferably projects in the lateral or oblique direction, but may be linear. It is more preferable that the tip of the probe portion 64 is sharpened.

A drive coil 66 made of metal or the like is formed in the vibration excitation section 62, and both ends of the drive coil 66 are connected to pads 68 and 69 on the support 61, respectively. A vibration detection coil 67 for detecting the vibration state of the vibration unit 63 is formed in the vibration unit 63 instead of the light reflecting surface. Both ends of the vibration detecting coil 67 are connected to pads 70 and 71 on the support 61, respectively.

The probe having such a configuration is used for the vibrating section 63.
It is installed in a magnetic field parallel to the width direction of. In addition, pad 6
An AC current is passed between 8 and 69 to generate a Lorentz force in the direction of torsion in the vibration excitation section 62 in which the driving coil 66 is formed, and the direction of the current flowing between the pads 68 and 69 is determined by the torsional resonance of the probe. Change at a frequency equal to the frequency. Thereby, the vibration excitation unit 62, the vibration unit 63,
And the probe part 64 can be excited to a torsional resonance state. With such torsional vibration of the probe, the vibrating portion 63
Since the magnetic flux passing through the detection coil 67 changes, an induced current flows through the detection coil 67. Therefore, pad 70
By detecting the current between the oscillating section 63 and the oscillating section 71, the amplitude and frequency of the torsional vibration of the vibrating section 63 can be detected.

When an interaction force is generated between the probe portion 64 of the probe and the sample, the probe portion 64 is drawn in the direction of the force,
The probe part 64 and the vibrating part 63 deviate from the rotation axis. Accordingly, the moment of inertia increases.
3, the state of the torsional vibration, that is, the amplitude and the frequency change. The change in the amplitude and frequency of the torsional vibration of the vibrating portion 63 of the probe can be detected by the induced current flowing through the detection coil 67 of the vibrating portion 63. Therefore, by detecting the magnitude and frequency of the induced current flowing through the detection coil 67, the interaction force between the probe portion 64 of the probe and the sample can be detected, and the shape of the sample can be imaged. .

FIG. 13 is a conceptual front view of a probe of a scanning probe microscope according to a fourth embodiment of the present invention. The probe shown in FIG. 13 has substantially the same configuration as the probe of FIG. 12, except for the shape of the coil formed on the probe.

In the probe shown in FIG. 13, two driving coils 72 and 73 made of metal or the like are formed in the vibration excitation section 62, and both ends of the driving coils 72 and 73 are supported by the support 61. The pads are connected to pads 74, 75, 76, and 77, respectively.

Also in the probe of FIG. 13, similarly to the probe of FIG. 12, the probe is set in a magnetic field and the direction of the current flowing through the driving coils 72 and 73 is set at a frequency equal to the torsional resonance frequency of the probe. By changing it, the probe is excited into a torsional resonance state, and by detecting the magnitude and frequency of the induced current flowing through the detection coil 67, the probe portion 64 of the probe is detected.
It is possible to detect the interaction force between the sample and the sample, and to image the sample shape.

FIG. 14 is a conceptual front view of a probe of a scanning probe microscope according to a fifth embodiment of the present invention. The probe shown in FIG. 14 is different from the probe shown in FIG. 13 in that a vibration detecting piezoelectric thin film 78 is formed instead of the detecting coil 67.
Has almost the same configuration as that of the probe. The vibration detecting piezoelectric thin film 78 is formed integrally with the coupling torsion portion 65 between the vibration excitation portion 62 and the vibration portion 63 of the probe, and is connected to the pads 79 and 80 of the support 61.

In the probe of FIG. 14, similarly to the probe of FIG. 13, the probe is set in a magnetic field, and the direction of the current flowing through the driving coils 72 and 73 is set to a frequency equal to the torsional resonance frequency of the probe. , The probe is excited to a torsional resonance state. In the vibration detecting piezoelectric thin film 78, an electromotive force is generated by distortion due to torsional vibration. This electromotive force changes depending on the amplitude and frequency of the torsional vibration. Therefore, the change in the interaction force between the probe portion 64 of the probe and the sample can be detected by detecting the magnitude and frequency of the electromotive force generated in the vibration detecting piezoelectric thin film 78.

FIG. 15 is a conceptual front view of a probe of a scanning probe microscope according to a sixth embodiment of the present invention. The probe shown in FIG. 15 has substantially the same configuration as the probe of FIG. 14 except that piezoelectric thin films 81 and 82 for driving are formed instead of the coils 72 and 73 for driving. The driving piezoelectric thin films 81 and 82 are formed integrally with the vibration excitation unit 62, and the pads 83, 84, 85 and 8 of the support 61 are respectively provided.
6 is connected.

In the probe shown in FIG. 15, the probe can be vibrated by applying an AC voltage to the driving piezoelectric thin films 81 and. The change in the interaction force between the probe portion 64 of the probe and the sample is detected by detecting the magnitude and frequency of the electromotive force generated in the vibration detecting piezoelectric thin film 78, similarly to the probe of FIG. Can be. In the probe shown in FIG. 15, since the excitation and vibration of the probe are detected by the piezoelectric thin film, it is not necessary to apply an external magnetic field.

FIG. 16 is a conceptual front view of a probe of a scanning probe microscope according to a seventh embodiment of the present invention. The probe shown in FIG. 16 is substantially the same as the probe of FIG. 15 except that a detection coil 67 such as that formed on the probe of FIG. 13 is formed instead of the piezoelectric thin film 78 for vibration detection. It has a configuration of The detection coil 67 is formed on the vibrating section 63, and both ends of the detection coil 67 are connected to the pads 70 and 71 on the support 61, respectively.

In the probe of FIG. 16, similarly to the probe of FIG. 15, the probe can be vibrated by applying an AC voltage to the driving piezoelectric thin films 81 and 82. The change in the interaction force between the probe portion 64 of the probe and the sample is shown in FIG.
As in the case of the probe described above, the detection can be performed by detecting the magnitude and frequency of the induced current flowing through the detection coil 67 provided in the magnetic field.

FIG. 17 is a conceptual front view of a probe of a scanning probe microscope according to an eighth embodiment of the present invention. The probe shown in FIG. 17 has a vibration detecting resistor 8 made of a resistor such as a piezoresistive element instead of the vibration detecting coil 67.
Except for the formation of 7, the probe has substantially the same configuration as the probe of FIG. The vibration detection resistor 87 is formed integrally with the coupling torsion portion 65 between the vibration excitation portion 62 and the vibration portion 63 of the probe, and is connected to the pads 88 and 89 of the support 61.

In the probe shown in FIG. 17, similarly to the probe shown in FIG. 13, the probe is set in a magnetic field and the direction of the current flowing through the driving coils 72 and 73 is set at a frequency equal to the torsional resonance frequency of the probe. By changing it, the probe is excited to a torsional resonance state. The resistance of the vibration detecting resistor 87 changes due to distortion caused by torsional vibration. For this reason, the resistance value of the vibration detecting resistor 87 changes according to the change in the amplitude and frequency of the torsional vibration. Therefore, a change in the interaction force between the probe portion 64 of the probe and the sample can be detected by detecting a change in the resistance value of the vibration detection resistor 87.

FIG. 18 is a conceptual front view of a probe of a scanning probe microscope according to a ninth embodiment of the present invention. The probe shown in FIG. 18 has a vibration detecting resistor 87 made of a resistor such as a piezoresistive element formed on the probe of FIG. 17 instead of the vibration detecting piezoelectric thin film 78. Has almost the same configuration as the probe of FIG.

In the probe shown in FIG. 18, similarly to the probe shown in FIG. 15, the probe can be vibrated by applying an AC voltage to the driving piezoelectric thin films 81 and 82. The change in the interaction force between the probe portion 64 of the probe and the sample is shown in FIG.
As in the case of the probe of the above, it can be detected by detecting a change in the resistance value of the vibration detecting resistor 87. The probe of FIG. 18 does not require application of an external magnetic field.

The probe shown in FIGS. 12 to 18 has an excitation structure in the probe itself. Therefore, it is not necessary to use an external mechanism such as a vibrator to excite torsional resonance as in the case of the probe of FIG. The change in the amplitude or the frequency of the torsional resonance of the probe is not detected by the optical lever method as in the case of the probe of FIG. Therefore, in the scanning probe microscope, an oscillator, a semiconductor laser, a four-division photodiode, and the like are not required, and it is not necessary to secure an optical path from the laser to the four-division photodiode via the light reflecting surface of the probe. Therefore, the device can be reduced in size and simplified. There is no need for troublesome adjustment work such as laser beam alignment required by the optical lever method, and the time required for observation or measurement can be reduced.

Next, a method of manufacturing the probe shown in FIGS. FIG. 19 is a schematic view showing a manufacturing process of the probe shown in FIGS. 12 to 16, and FIG. 20 is a schematic view when it is viewed from above.

First, in the same manner as in FIG.
1, a silicon nitride film 12 having a thickness of about 0.1 μm,
13 is formed. Next, the silicon nitride films 12 and 13 are patterned by a dry etching method in substantially the same manner as in FIG.
3 and the shape of the probe portion 64 are formed (FIG. 19).
(A), FIG. 20 (a)).

Next, on the patterned silicon nitride film 12, a required one of a driving coil, a vibration detecting coil, a vibration detecting piezoelectric thin film, a driving piezoelectric thin film, and a pad is formed by a lift-off method. The corresponding metal film 90 or a metal film and a piezoelectric thin film having a thickness of about 10 nm are patterned (FIGS. 19B and 20B).

Finally, the substrate 1 is impregnated with an aqueous solution of potassium hydroxide (KOH) in substantially the same manner as in FIG.
1 is removed (FIGS. 19C and 20C).
Thus, the probe having the driving coil, the vibration detecting coil, the vibration detecting piezoelectric thin film, the driving piezoelectric thin film, the pad, etc. as shown in FIGS. Can be manufactured.

Although the tip of the probe formed by such a manufacturing method is linear, a driving coil, a vibration detecting coil, and a vibration detecting piezoelectric thin film are used in the method shown in FIG. By patterning a metal film or a piezoelectric thin film corresponding to a driving piezoelectric thin film and a pad, it is also possible to form a probe of a scanning probe microscope in which a tip portion of a probe portion protrudes laterally or obliquely.

Next, a method of manufacturing the probe shown in FIG. 17 will be described. FIG. 21 is a schematic view showing a manufacturing process of the probe of FIG.

First, an SOI substrate including a single-crystal silicon substrate 101 having a thickness of, for example, about 500 μm, a silicon oxide film 102 having a thickness of, for example, about 500 nm, and a single-crystal silicon layer 103 having a thickness of, for example, about 200 nm is prepared. Both surfaces of this substrate are oxidized to, for example, a silicon oxide film 10 having a thickness of about 50 nm.
4 and 105 are formed.

Next, the opening 106 is formed by partially removing the silicon oxide film 104 on the upper surface of the substrate by a wet etching method.

Next, the silicon layer 1 is
For example, boron or the like is diffused into the exposed portion of the substrate 03 by a thermal diffusion method to form a resistor 107 corresponding to the vibration detecting resistor 87 of FIG. 17 (FIG. 21A).

Next, the substrate is oxidized again so that the upper surface of the substrate is covered with the silicon oxide film 108 (FIG. 21B).

Next, the silicon oxide film 108 on the upper surface of the substrate is partially removed by wet etching, and the support 6 shown in FIG.
1. Patterning into a shape corresponding to the vibration excitation section 62, the vibration section 63, and the probe section 64. Further, the exposed portion of the silicon layer 103 is removed and patterned using a silicon etching solution such as a TMAH aqueous solution or a KOH aqueous solution (FIG. 2).
1 (c)). FIG. 21 (g) is a conceptual diagram of the substrate as viewed from above.

Next, the patterned silicon layer 103
A silicon oxide film is formed on the side wall of the silicon layer 103 so that the upper surface and the side wall of the silicon layer 103 are covered with the silicon oxide film 109. Next, the silicon oxide film 10 is exposed so that the resistor 107 is exposed.
9 is partially removed to form an opening 110 (FIG. 21).
(D)).

Next, the metal film 111 corresponding to the driving coil, the pad, the wiring between the vibration detecting resistor and the pad, and the like is patterned by the lift-off method. Metal film 1
For example, gold, nichrome, aluminum or the like can be used for 11. The metal film 111 is also in contact with the resistor 107 via the opening 110 (FIG. 21E).
FIG. 21 (h) is a conceptual diagram of the substrate as viewed from above.

Next, the silicon oxide film 105 on the back surface of the substrate is partially removed, and the exposed portion of the silicon
It is removed with a silicon etching solution such as an MAH aqueous solution or a KOH aqueous solution (FIG. 21F). As a result, the probe on which the driving coil, the vibration detecting resistor, the pad, and the like as shown in FIG. 17 are formed can be collectively and inexpensively manufactured using the semiconductor technology.

Next, a method of manufacturing the probe shown in FIG. 18 will be described. FIG. 22 is a conceptual diagram showing a method of forming the piezoelectric thin film for driving, a pad, and wiring between the pad and the piezoelectric thin film for driving or the resistance for vibration detection among the manufacturing methods of the probe of FIG. FIG. 22A corresponds to FIG. 21D as viewed from above. The probe of FIG.
Except for the formation of the piezoelectric thin film for driving and the pad, it can be manufactured by a method substantially similar to the probe of FIG.

First, on the substrate shown in FIG.
The pads 84, 86, 88 and 8 are lifted off by the lift-off method.
9, the lower electrodes of the driving piezoelectric thin films 81 and 82, the wiring between the vibration detecting resistor 87 and the pads 88 and 89, and the wiring between the driving piezoelectric thin films 81 and 82 and the pads 84 and 86. The lower metal film 121 is patterned on the corresponding portions (FIG. 22B).

Next, the piezoelectric thin film 122 is patterned on portions of the lower metal film 121 corresponding to the lower electrodes of the driving piezoelectric thin films 81 and 82 (FIG. 22C).

Next, the upper metal film 123 is patterned on the portions corresponding to the pads 83 and 85, the wiring between the driving piezoelectric thin films 81 and 82 and the pads 83 and 85, and on the piezoelectric thin film 122. (FIG. 22D).

As a result, it is possible to form a driving piezoelectric thin film composed of a piezoelectric thin film sandwiched between metal films. In the manufacturing method shown in FIG.
When the lower metal film 121, the piezoelectric thin film 122, and the upper metal film 123 shown in FIG. 21 are formed instead of FIG. Needles can be manufactured.

Next, the overall configuration of a scanning probe microscope using the probe shown in FIGS. 12 to 18 will be described. FIG. 23 is an overall configuration diagram of a scanning probe microscope using the probe shown in FIGS. 12 to 18, and FIG.
FIG. 6 is a block diagram illustrating an outline of an operation of the scanning probe microscope 3. The same components as those of the scanning probe microscope in FIGS. 5 and 6 are denoted by the same reference numerals.

Unlike the scanning probe microscope of FIG.
In the scanning probe microscope of FIG. 23, the support 61 of the probe is directly held or adhered to the free end side of the PZT 31 for driving in the Z-axis direction. The other end of the Z-axis direction driving PZT element 31 is fixed to a block 32. The free ends of the PZT element 33 for driving in the X-axis direction and the PZT element 34 for driving in the Y-axis direction, both of which are piezoelectric elements, are fixed to the block 32.
It is fixed to. The frame 35 is supported by three micrometers 36. Also, the clip 30, the vibrator 39, the semiconductor laser 6, the mirror 37 shown in FIG.
Also, the four-division photodiode 7 and the like are unnecessary.

The scanning probe microscope having such a configuration performs imaging of the surface shape of the sample 5 by the following operation. First, when the probe shown in FIGS. 12 to 14, 16, and 17 is used, a magnetic field in a direction parallel to the vibrating portion 63 of the stationary probe (in the X-axis direction in FIG. 23) by an electromagnet (not shown) or the like. To cause the probe to be held in the magnetic field. When the probe shown in FIGS. 15 and 18 is used, such a magnetic field is unnecessary.

Next, the signal generator 91 controlled by the excitation signal generated by the DSP 40 outputs an AC signal corresponding to the torsional resonance frequency of the probe. Excitation power supply 9
Numeral 2 receives an output signal of the signal generator 91, outputs an amplified signal, and inputs the amplified signal to a driving coil or a driving piezoelectric thin film formed in the vibration excitation unit 62 of the probe. As a result, the probe is vibrated, and torsional resonance is excited in the probe.

On the other hand, the probe drive signal generated by the DSP 40 is converted into a voltage by the DA conversion circuit 41, boosted by the high voltage amplifier 42, and then applied to the probe driving PZT elements 33 and 34. . As a result, the probe moves in the plane direction of the sample, and the probe portion 6 of the probe is moved.
The relative distance between the sample 4 and the sample 5 changes. Accordingly, the interaction force between the sample 5 and the probe portion 64 of the probe changes, and the torsional resonance frequency and amplitude of the probe also change.

In accordance with the torsional vibration of the probe, the voltage generated by the vibration detecting coil provided in the vibrating portion 63 of the probe or the piezoelectric thin film or the vibration detecting resistor provided in the connecting torsion of the probe. The signal includes information on the interaction force between the sample 5 and the probe portion 64 of the probe. This voltage signal is amplified by the preamplifier 43 and input to the lock-in amplifier 44.

The lock-in amplifier 44 amplifies and outputs an excitation frequency component (ie, a component having the same frequency as the frequency of the AC signal output from the signal generator 91) or a frequency component slightly different from the excitation frequency. Lock-in amplifier 44
The signal corresponding to the frequency and amplitude of the torsional vibration of the probe amplified by is digitized by the AD converter 45,
Input to the DSP 40.

In the DSP 40, a servo calculation for keeping the relative distance between the sample 5 and the probe 64 constant corresponding to the change in the interaction force between the sample 5 and the probe 64 of the probe. Is performed, and the feedback signal is passed through the DA conversion circuit 41 and the high-voltage amplifier 42 so that the PZT
31 is applied. This feedback signal reflects the surface shape of the sample 5, is displayed on a display by a personal computer 47 connected to the DSP 40, and the data is stored.

Although a specific embodiment has been described, the present invention is not limited to the above-described embodiment. Further, the present invention is not limited to the atomic force microscope, for example, if a conductive film such as a metal film or a magnetic film is formed at the tip of the probe portion of the probe, a scanning tunneling microscope, a scanning capacitance microscope, The present invention can be applied to various scanning probe microscopes such as a scanning electrostatic force microscope and a scanning magnetic force microscope.

[0135]

As described above, according to the first to eleventh aspects of the present invention, it is possible to easily insert the semiconductor sample into a fine groove or the like, and to accurately determine the interaction with the sample. A probe of a scanning probe microscope capable of detecting the probe can be provided.

According to the present invention, a probe of a scanning probe microscope having a thin and sharp tip or a probe can be easily and stably manufactured by using a semiconductor manufacturing technique. The mass production of the probe is easy, and the cost of the product can be reduced.

According to the present invention, the force acting between the probe of the scanning probe microscope and the sample can be detected with high sensitivity without contact. Also, there is little spatial restriction when inserting the probe into the fine groove of the sample. Since the interaction force between the vertical side wall of the sample and the probe can also be accurately detected, it is possible to precisely observe or measure the sample having fine irregularities.

[Brief description of the drawings]

FIG. 1 is a perspective view conceptually showing a probe of a scanning probe microscope according to a first embodiment of the present invention.

FIG. 2 is a schematic view showing a manufacturing process when a tip portion of a probe portion of the probe of FIG. 1 is linear.

FIG. 3 is a schematic view showing a manufacturing process in a case where a tip portion of a probe portion of the probe of FIG. 1 projects in an oblique direction.

FIG. 4 is a perspective view conceptually showing a method of detecting a force acting between the probe and the sample using the probe of FIG.

5 is an overall configuration diagram of a scanning probe microscope using the probe of FIG. 1;

6 is a block diagram showing the operation of the scanning probe microscope of FIG.

7 is a conceptual diagram showing a method for detecting a force acting between a probe and a sample in FIG. 1 in a non-contact manner.

FIG. 8 is a conceptual diagram showing a state in which an object is inclined from an axis by an angle θ.

FIG. 9 is a conceptual diagram showing a state in which the shape of the sample is imaged by scanning the probe of FIG. 1 at an angle with respect to the sample.

FIG. 10 is a perspective view conceptually showing a probe of a scanning probe microscope according to a second embodiment of the present invention.

FIG. 11 is a schematic view showing a manufacturing process of a probe of the scanning probe microscope of FIG.

FIG. 12 is a front view conceptually showing a probe of a scanning probe microscope according to a third embodiment of the present invention.

FIG. 13 is a front view conceptually showing a probe of a scanning probe microscope according to a fourth embodiment of the present invention.

FIG. 14 is a front view conceptually showing a probe of a scanning probe microscope according to a fifth embodiment of the present invention.

FIG. 15 is a front view conceptually showing a probe of a scanning probe microscope according to a sixth embodiment of the present invention.

FIG. 16 is a front view conceptually showing a probe of a scanning probe microscope according to a seventh embodiment of the present invention.

FIG. 17 is a front view conceptually showing a probe of a scanning probe microscope according to an eighth embodiment of the present invention.

FIG. 18 is a front view conceptually showing a probe of a scanning probe microscope according to a ninth embodiment of the present invention.

FIG. 19 is a schematic view showing a manufacturing process of a probe of the scanning probe microscope of FIGS.

FIG. 20 is a schematic view of FIG. 19 as viewed from above.

FIG. 21 is a schematic view showing a manufacturing process of a probe of the scanning probe microscope of FIG.

FIG. 22 is a schematic view showing a step of forming a piezoelectric thin film for driving a probe and a pad of the scanning probe microscope of FIG. 18;

FIG. 23 is an overall configuration diagram of a scanning probe microscope using the probe of FIGS.

24 is a block diagram showing the operation of the scanning probe microscope of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Support body 2 Cantilever part 3 Detection part 4 Probe part 5 Trench 6 Semiconductor laser 7 Split type photodiode 8 Van der Waals force 9 Central axis 11 Semiconductor substrate 12, 13 Silicon nitride film 14 Resist film 15 Gold layer 16 Mirror part 17 Resist film 18 Thin film portion 19 Constricted portion 20 Opening 21 Groove 22 Inclined surface 23, 24 Silicon nitride film 30 Clip 31 PZT element for driving in Z-axis direction 32 Block 33 PZT element for driving in X-axis direction 34 PZT element for driving in Y-axis direction 35 Frame 36 Micrometer 37 Mirror 38 Electric circuit 39 Transducer 40 Digital signal processor 41 DA conversion circuit 42 High voltage amplifier 43 Preamplifier 44 Lock-in amplifier 45 AD converter 46 Oscillation circuit 47 Personal computer 48 Object 49 Axis 50 Sample 5 Wiring 52, 53 Pad 61 Supporting body 62 Vibration excitation part 63 Vibration part 64 Probe part 65 Connection torsion part 66 Driving coil 67 Vibration detecting coil 68-71 Pad 72, 73 Driving coil 74-77 Pad 78 Vibration detecting Piezoelectric thin film 79, 80 Pad 81, 82 Piezoelectric thin film for driving 83 to 86 Pad 87 Resistance for vibration detection 88, 89 Pad 90 Metal film 91 Signal generator 92 Vibration power supply 101 Silicon substrate 102 Silicon oxide film 103 Silicon layer 104, 105 Silicon oxide film 106 Opening 107 Resistor 108, 109 Silicon oxide film 110 Opening 111 Metal film 121 Lower metal film 122 Piezoelectric thin film 123 Upper metal film

Claims (21)

[Claims] 1. A support unit, a probe unit, and a detection unit provided between the support unit and the probe unit, for detecting an interaction between the probe unit and a sample, The probe of a scanning probe microscope, wherein the detection section and the probe section are formed substantially on the same axis. 2. The probe according to claim 1, wherein the detection unit includes a light reflection unit that reflects light. 3. The probe according to claim 1, wherein the detection unit has at least one coil pattern. 4. The probe according to claim 1, wherein the detection section has a piezoelectric thin film. 5. The probe according to claim 1, wherein the detection section has a resistor. 6. The probe according to claim 1, wherein the support, the detector, and the probe are formed on substantially the same plane. 7. A probe, comprising a support, a probe portion, and a cantilever connecting the support and the probe portion, and causing the probe portion to resonate around a central axis of the probe portion. A probe for a scanning probe microscope, wherein a mass part at the time is provided on the cantilever. 8. A probe, comprising: a support, a probe portion, and a cantilever connecting the support and the probe, wherein the cantilever is provided with a light reflecting portion for detecting displacement of the probe portion. The probe is provided on the same plane as the
A probe for a scanning probe microscope, wherein the probe is formed to be not more than 00 nm and not less than 1 μm in length. 9. A support, a vibration excitation unit connected to the support, a vibration unit connected to the vibration excitation unit, and a probe unit connected to the vibration unit and having a smaller width than the vibration unit. A probe for a scanning probe microscope, wherein the vibration excitation section, the vibration section, and the probe section are formed substantially on the same axis. 10. The probe according to claim 9, wherein the vibration excitation section, the vibration section, and the probe section are formed of an integral thin film plate protruding from the support. 11. The probe of a scanning probe microscope according to claim 9, wherein the vibration excitation section has a driving coil pattern or a driving piezoelectric thin film. 12. preparing a semiconductor substrate, forming a first layer on the semiconductor substrate, forming a second layer on the first layer, patterning the second layer. Forming a patterned second layer having a first portion, a second portion, a third portion, a fourth portion, and a fifth portion, comprising:
The first portion has a shape that tapers toward the second portion, and the second portion has a shape that tapers toward the first portion, whereby the first portion and The second portion is in contact with and forms a narrowed portion, the third portion is in contact with the second portion and has a wider width than the second portion, and the fourth portion is The third portion is in contact with the third portion and has a width smaller than the third portion, and the fifth portion is in contact with the fourth portion and has a wider width than the fourth portion; Etching the first layer using the patterned second layer as a mask, removing the patterned second layer, and removing at least a portion of the semiconductor substrate. A method for manufacturing a probe of a scanning probe microscope, characterized by comprising: 13. preparing a semiconductor substrate, forming a first layer on the semiconductor substrate, forming a second layer on the first layer, patterning the second layer. Forming an opening by forming a metal layer on the patterned second layer and the opening; forming the patterned second layer on the patterned second layer; Forming a metal part made of the metal layer at a position corresponding to the opening and on the first layer, thereby forming a metal part on the first layer and the metal part. Forming a third layer; patterning the third layer to form a patterned third having a first portion, a second portion, a third portion, a fourth portion, and a fifth portion. Forming a layer of
The first portion has a shape that tapers toward the second portion, and the second portion has a shape that tapers toward the first portion, whereby the first portion and A second portion is in contact with the first portion to form a narrowed portion, the third portion is in contact with the second portion while covering the metal portion, and has a wider width than the second portion; A fourth portion is in contact with the third portion and has a smaller width than the third portion, and the fifth portion is in contact with the fourth portion and has a wider width than the fourth portion. Etching the first layer using the patterned third layer as a mask; removing the patterned third layer; removing at least a portion of the semiconductor substrate Scanning probe, comprising: How to make a microscope probe. 14. After the step of preparing the semiconductor substrate and before the step of forming the first layer on the semiconductor substrate, the semiconductor substrate is etched to form an inclined portion and a flat portion on the semiconductor substrate. And wherein the first portion and the second portion are at least partially on an inclined portion of the semiconductor substrate, and wherein the third portion, the fourth portion, and the fifth portion are the semiconductor portions. 14. The semiconductor device according to claim 12, wherein the reduced-width portion on the flat portion of the substrate and where the first portion and the second portion contact each other is on an inclined portion of the semiconductor substrate. A method for producing a probe for a scanning probe microscope according to any one of the above. 15. The semiconductor device according to claim 12, wherein the semiconductor substrate is a silicon substrate, and the first layer is one of a silicon nitride layer and a silicon oxide layer. Method for manufacturing a probe of a scanning probe microscope. 16. A method of causing a probe to make a predetermined reciprocating rotational movement about a central axis of the probe, and detecting a force acting on the probe by detecting a change in the reciprocating rotational movement. Characteristic force detection method for scanning probe microscope. 17. A support, a support protruding from the support and formed substantially coaxially, a detector connected to the support and wider than the support, and connected to the detector. And a force detecting method of a scanning probe microscope using a probe having a probe portion narrower than the detecting portion, wherein a torsional resonance is excited in the detecting portion, and a change in the moment of inertia of the detecting portion. Detecting a force acting on the probe section by detecting the force. 18. A support, a support protruding from the support and formed substantially coaxially, a detector connected to the support and wider than the support, and connected to the detector. A force detecting method for a scanning probe microscope using a probe having a probe portion having a width smaller than that of the detecting portion, wherein a torsional resonance is excited in the detecting portion, and an amplitude of the detecting portion in a torsional direction is provided. A force detecting method for a scanning probe microscope, wherein a force acting on the probe portion is detected by detecting a change in the force. 19. A support, a support protruding from the support and formed substantially on the same axis, a detector connected to the support and wider than the support, and connected to the detector. And a force detecting method for a scanning probe microscope using a probe having a probe portion narrower than the detection portion, wherein a torsional resonance is excited in the detection portion, and a frequency of the torsional resonance of the detection portion. A force detecting method for a scanning probe microscope, wherein a force acting on the probe portion is detected by detecting a change. 20. The force detection method for a scanning probe microscope according to claim 17, wherein the torsional resonance is excited by exciting the support with a vibrator. 21. A vibration excitation section having a driving piezoelectric thin film or a driving coil pattern formed on the support section, and the probe is set in an external magnetic field by passing an alternating current through the driving piezoelectric thin film. 20. The force detection method for a scanning probe microscope according to claim 17, wherein the torsional resonance is excited by passing an alternating current through the driving coil pattern.