JPH08285868A - Fabrication of cantilever for scanning probe microscope - Google Patents

Abstract

PURPOSE: To stably mass produce a cantilever equipped with a probe not having a double tip. CONSTITUTION: A square opening 4a is made through silicon nitride 4 deposited on a silicon substrate 7 by photolithographic etching using a lens projection aligner. The exposed silicon substrate 7 is then etched conically to form a conical trench 7a. The trench 7a part is then oxidized to deposit a silicon oxide 8. Subsequently, a silicon nitride 5 is deposited on the silicon nitride 4 and the silicon oxide 8. The silicon nitrides 4, 5 are patterned according to the shape at a thin film beam part. A glass member 6 is then bonded onto the silicon nitride 5. Finally, the silicon substrate 7 and the silicon oxide 8 are removed from the part corresponding to the thin film beam part.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a cantilever for a scanning probe microscope used in a scanning probe microscope such as a scanning atomic force microscope.

[0002]

2. Description of the Related Art Conventionally, in a scanning probe microscope such as a scanning atomic force microscope, for example, as shown in FIG.
A cantilever including a support body 1, a thin film beam portion (lever) 2 whose one end is supported by the support body 1, and a probe 3 provided in a distal end side region of the thin film beam portion 2 is used. FIG. 1 is a view showing this cantilever, FIG. 1 (a) is a perspective view thereof, and FIG. 1 (b) is a sectional view taken along the line I-I in FIG. 1 (a). 1 (a) and 1 (b) are shown upside down.

In the cantilever shown in FIG. 1, the thin film beam portion 2 is composed of a silicon nitride film 4 and a silicon nitride film 5 formed on the silicon nitride film 4. As shown in FIG. 1B, an opening 4a is formed in the tip side region of the silicon nitride film 4, and the silicon nitride film 5 is located below the opening 4a (see FIG. 1A).
In the above), it is protruding like a cone. The portion of the silicon nitride film 5 protruding like a cone from the opening 4 a constitutes the probe 3. The silicon nitride films 4 and 5 extend not only to the portion of the thin film beam portion 2 but also to the portion of the support 1, and the portions of the silicon nitride films 4 and 5 and the glass member 6 bonded to this portion are the support 1 described above.
Is composed.

For example, in an atomic force microscope, the probe 3 of the cantilever is arranged facing and close to the sample surface. When the probe 3 is brought close to the sample surface, a force acts on the tip of the probe 3 and the cantilever bends. By scanning the cantilever relative to the sample surface and detecting the amount of bending, the three-dimensional shape of the sample surface can be observed with atomic level resolution.

In the cantilever as described above, a sharp probe having a small tip diameter is required in order to obtain a lateral resolution on the order of nanometer when observing the surface shape and the like.

The method for producing the above-described cantilever is described, for example, in “TRAlbrecht, S. Akamine, TE Carver,
and CFQuate: Microfabrication of cantilever
styli for the atomic force microscope J.Va
c.Sci.Technol.A8 (4), Jul / Aug 1990- ".

Next, a conventional method of manufacturing the cantilever shown in FIG. 1 will be described with reference to FIG. FIG. 2 is a schematic cross-sectional view showing a method for manufacturing the cantilever shown in FIG. In FIG. 2, elements corresponding to those in FIG. 1 are designated by the same reference numerals.

First, a silicon substrate 7 having a (100) plane orientation
A silicon nitride film 4 is formed on the entire surface by vapor phase epitaxy.
After that, a square opening 4a exposing the surface of the silicon substrate 7 is formed at a predetermined position of the silicon nitride film 4 (FIG. 2).
(A)). The opening 4a is formed by exposing the silicon nitride film 4 to the same size using a mask patterned in a square shape having the same size as the opening 4a, and photolithographically etching the silicon nitride film 4.

Next, the substrate in the state shown in FIG.
The opening 4a of the silicon nitride film 4 is formed by immersing the silicon substrate 7 exposed in the anisotropic etching solution such as an H aqueous solution or a TMAH (tetramethylammonium hydroxide) aqueous solution in a square pyramid shape. A quadrangular pyramid-shaped trench 7a continuous with is formed in the silicon substrate 7 (FIG. 2B). Such a trench 7a is formed by utilizing the crystal orientation dependence of the etching rate. That is, since the substrate 7 having the (100) plane orientation is used, it is well known that the etching of the
1) The surface of the trench 7a is 5 because it automatically stops at the surface.
The taper surface has an angle of 4.7 °.

Thereafter, the exposed portion of the trench 7a of the substrate 7 is oxidized by a thermal oxidation method to form a silicon oxide film 8 in that portion (FIG. 2C).

Next, while leaving the silicon nitride film 4 on the substrate 7 in the state shown in FIG. 2C, the silicon nitride film 5 is formed so as to cover the surface of the silicon nitride film 4 and the surface of the silicon oxide film 8. Are formed by a vapor phase growth method or the like. The portion of the silicon nitride film 5 formed on the silicon oxide film 8 becomes the probe 3.

Thereafter, the silicon nitride films 4 and 5 are patterned according to the shape of the thin film beam portion 2 (FIG. 2).
(D)). This patterning is performed by using a mask patterned in the same size as the shape of the thin film beam portion 2,
The silicon nitride films 4 and 5 are exposed to the same size, and the silicon nitride films 4 and 5 are exposed.
By photolithographic etching.

Next, the glass member 6 is bonded onto the silicon nitride film 5 (FIG. 2 (e)).

Finally, the silicon substrate 7 and the silicon oxide film 8
Are removed by etching. As a result, the cantilever shown in FIG. 1 is completed.

[0015]

8 (a) and 8 (b) are perspective views showing the cantilever probe 3 manufactured by the above-described conventional manufacturing method.

Normally, a large number of cantilevers are simultaneously manufactured by using the same silicon substrate (for example, a silicon wafer having a diameter of 3 inches or more) 7. However, a large number of cantilevers simultaneously manufactured by the conventional manufacturing method described above are used. In addition to the cantilever in which the shape of the probe 3 has only one vertex (desired shape) as shown in FIG. 8A, the shape of the probe 3 is as shown in FIG. 8B. Has 2 vertices
A considerable number of cantilevers, which have a shape in which the tip is separated into two, are included. The probe 3 having a shape as shown in FIG. 8B is called a double tip. Regarding the influence of the double tip, UDSCHWARZ et al.
D.SCHWARZ, H.HAEFKE, P.REIMANN, HJGUNTHERODT: Tip ar
tefacts in scanning force microscopy.J. Microscopy,
Vol173, Pt3, March 1994, pp.183-197 ”.
As shown in FIG. 9A, when the sample 10 having one microprotrusion 10a is observed by the probe 3 having the double tip as shown in FIG. 8B, the probe 3 is scanned according to the scanning of the probe 3. Since the two vertices come into contact with the protrusions 10a sequentially, an image 11 as if the sample 10 had two protrusions was obtained as shown in FIG.
No true surface shape can be obtained. Therefore, the cantilever having the probe having the double tip cannot be actually used and becomes a defective product. Therefore, in the above-described conventional method for manufacturing a cantilever, since a large number of cantilevers having the probe having such a double tip can be produced, there is a drawback that the yield is poor. Therefore, in the conventional manufacturing method described above, the tip radius is 10n.
Although a cantilever with a m probe has already been manufactured,
It was very difficult to manufacture a large number of cantilevers having a probe having the tip diameter stably.

In a so-called non-contact type atomic force microscope, the resonance frequency shifts when a force is applied between the probe and the sample by vibrating the cantilever near the resonance frequency. The surface shape of the sample is obtained by detecting. Therefore, when the cantilever is used in a non-contact type atomic force microscope, the thin film beam portion of the cantilever needs to have a predetermined resonance frequency characteristic. However, not only cantilevers having a predetermined resonance frequency characteristic but also characteristics deviated from the predetermined resonance frequency characteristic, for example, a plurality of resonance frequency peaks, are included in many cantilevers simultaneously manufactured by the above-described conventional manufacturing method. A considerable number of cantilevers, which have the characteristic of having, are included. When a cantilever having such a characteristic having a plurality of resonance frequency peaks is used in a non-contact type atomic force microscope, the resolution of the non-contact type atomic force microscope deteriorates. Therefore, such a cantilever cannot be used as a cantilever for a non-contact type atomic force microscope, and becomes a defective product as a cantilever for a non-contact type atomic force microscope. Therefore, in the above-described conventional method for manufacturing a cantilever, a considerable number of cantilevers having a characteristic deviated from the predetermined resonance frequency characteristic can be produced.
There was a defect that the yield was poor. The adverse effect of the cantilever having a characteristic deviated from a predetermined resonance frequency characteristic is particularly remarkable in the non-contact type atomic force microscope, but it is also the same in other scanning probe microscopes.

The present invention has been made in view of the above circumstances. First, a method of manufacturing a cantilever for a scanning probe microscope capable of stably manufacturing a large number of cantilevers having a probe without a double tip. The purpose is to provide.

A second object of the present invention is to provide a method of manufacturing a cantilever for a scanning probe microscope, which can stably manufacture a large number of cantilevers having a predetermined resonance frequency characteristic.

[0020]

In order to solve the above-mentioned problems, a method of manufacturing a cantilever for a scanning probe microscope according to a first aspect of the present invention is directed to a support and a thin film-shaped one end of which is supported by the support. A method of manufacturing a cantilever for a scanning probe microscope, comprising a beam portion and a probe provided in a tip side region of the thin film beam portion, the method comprising forming a first inorganic material film on a silicon substrate. A step of forming a square opening that exposes the surface of the silicon substrate at a predetermined location of the first inorganic material film, and etching the portion of the silicon substrate exposed from the opening into a cone shape, Forming in the silicon substrate a conical trench continuous with the opening of the inorganic material film; and oxidizing the trench portion of the silicon substrate to form a silicon oxide film in the trench portion. Then, a second inorganic material film is formed on the first inorganic material film and the silicon oxide film without removing the first inorganic material film, or the first inorganic material film is formed. After removing, a step of forming a second inorganic material film on the silicon substrate and the silicon oxide film, and patterning the first and second inorganic material films according to the shape of the thin film beam portion. And a step of removing the silicon substrate and the silicon oxide film in a portion corresponding to the thin film beam portion. Then, in the step of forming the square-shaped opening, a reticle patterned into a square shape obtained by enlarging the shape of the square-shaped opening at a predetermined magnification is used to perform the reduction projection at the predetermined magnification to perform the first inorganic treatment. The material film is exposed to light and the first inorganic material film is photolithographically etched to form the square openings. As the first inorganic material film, for example, a silicon nitride film, a silicon oxide film or the like can be used. Similarly, as the second inorganic material film, for example, a silicon nitride film, a silicon oxide film, or the like can be used.

A method of manufacturing a cantilever for a scanning probe microscope according to a second aspect of the present invention is the manufacturing method according to the first aspect, wherein a reduction projection exposure device is used in the step of forming the square opening. The reduction projection is performed.

A method of manufacturing a cantilever for a scanning probe microscope according to the third aspect of the present invention is the first or second method described above.
In the manufacturing method according to the second aspect, in the step of patterning the first and second inorganic material films according to the shape of the thin film beam portion, the thin film beam portion is patterned into a shape enlarged at a predetermined magnification. Using the reticle formed by the projection, the first and second reticle are reduced and projected at the predetermined magnification.
Of the inorganic material film is exposed, and the first and second inorganic material films are photolithographically etched to pattern the first and second inorganic material films according to the shape of the thin film beam portion. is there.

In the method for manufacturing a cantilever for a scanning probe microscope according to the fourth aspect of the present invention, a support, a thin film beam portion whose one end is supported by the support member, and a tip side region of the thin film beam portion are provided. A method for manufacturing a cantilever for a scanning probe microscope having a probe provided in, comprising a step of patterning a thin film formed on a silicon layer according to the shape of the thin film beam portion. In the step, by using a reticle patterned to a shape obtained by enlarging the shape of the thin film beam portion at a predetermined magnification, the thin film is exposed by reduction projection at the predetermined magnification, and the thin film is photolithographically etched. The thin film is patterned according to the shape of the thin film beam portion.

A method of manufacturing a cantilever for a scanning probe microscope according to a fifth aspect of the present invention is the method according to the third or fourth aspect.
In the manufacturing method according to the above aspect, the thin film beam portion has a hollow shape.

[0025]

The reason why a large number of cantilevers having a probe having a double tip are included among the cantilevers manufactured at the same time by the conventional manufacturing method described above is as follows.
At first it was completely unknown, but as a result of the research of the inventor,
I was able to investigate the cause.

That is, the cause is that for the cantilever in which the double tip occurs, the shape of the recess 12 formed by the surface of the silicon oxide film 8 is as shown in FIG. 10 in the state shown in FIG. 2 (c). It was found to be due to Two vertices are formed at the bottom of the recess 12. Note that FIG. 10 is a diagram showing a main part of the substrate in the state shown in FIG. 2C regarding a cantilever in which a double tip occurs, FIG. 10A is its schematic plan view, and FIG. FIG. 10 is a schematic cross-sectional view taken along the line AA in FIG. 10A and is a schematic cross-sectional view corresponding to FIG.

The cause of the recess 12 having the shape shown in FIG. 10 is that the shape of the trench 7a in the state shown in FIG. It turned out that it was due to becoming. The bottom of the trench 7a is not a point but a line. Note that FIG. 11 is a diagram showing a main part of the substrate in the state shown in FIG. 2B regarding a cantilever in which a double tip occurs, FIG. 11A is its schematic plan view, and FIG. FIG. 11 is a schematic cross-sectional view taken along the line BB in FIG. 11A and corresponding to FIG.

Further, as a result of investigation, the reason why the bottom of the trench 7a does not have a perfect quadrangular pyramid shape but the bottom of the trench 7a is not a point but a line is that the square-shaped opening 4a formed in the silicon nitride film 4 is a square. Although it was designed as, it turned out that the length of each side is not exactly equal and the lengths vary. It is considered that this is because the trench 7a is formed by utilizing the crystal orientation dependence of the etching rate of silicon as described above.

As a result of the research by the inventor,
If the lengths of the sides of the square-shaped opening 4a formed in the silicon nitride film 4 are accurately matched and the opening 4a is accurately formed in the square shape, the occurrence of a cantilever that causes a double tip can be reduced. found.

The method of manufacturing a cantilever for a scanning probe microscope according to the first to third aspects of the present invention was made based on the results of such research, and a silicon nitride film or an oxide film formed on a silicon substrate was formed. In the step of forming a square-shaped opening that exposes the surface of the silicon substrate at a predetermined position of the first inorganic material film such as a silicon film, the square-shaped opening was patterned into a square shape enlarged at a predetermined magnification. The reticle is used to expose the first inorganic material film by reduction projection at the predetermined magnification, and the first inorganic material film is exposed.
By photolithographically etching the inorganic material film of
The square opening is formed. Therefore, such reduction projection exposure can easily increase the accuracy of the dimension of each side of the square opening, and thus it is possible to stably manufacture a large number of cantilevers having a probe without a double tip. You can

On the other hand, in the above-described conventional manufacturing method, the square-shaped opening 4a of the silicon nitride film 4 is formed by using a mask patterned into a square shape having the same size as the opening 4a, as already described. The silicon nitride film 4 was formed by performing equal-magnification exposure and photolithographically etching the silicon nitride film 4. Therefore, the accuracy of the length of each side of the opening 4a is determined by the accuracy of the mask. The dimensional accuracy with which the current mask can be manufactured is about ± 0.1 μm,
It is difficult to stably manufacture a mask with dimensional accuracy suppressed to about m. In particular, since a large number of cantilevers are formed on a silicon wafer having a diameter of 3 inches or more, a mask having a mask pattern corresponding to at least the same number of openings 4a as the cantilevers is required. Difficult and costly.

According to the method of manufacturing a cantilever for a scanning probe microscope according to the third to fifth aspects of the present invention, the thin film formed on the silicon layer is patterned according to the shape of the thin film beam portion. In the step, using a reticle patterned to have a shape obtained by enlarging the shape of the thin-film beam portion at a predetermined magnification, the thin-film is exposed by reduction projection at the predetermined magnification, and the thin-film is photolithoetched, thereby Is patterned according to the shape of the thin film beam portion. Therefore, according to such reduction projection exposure, the dimensional accuracy of the thin film beam portion can be easily increased, so that a large number of cantilevers having a predetermined resonance frequency characteristic can be stably manufactured. As in the fifth aspect of the present invention, when the shape of the thin film beam portion is a hollow shape, the dimensions of the portions on both sides of the hollow portion are slightly different, and a plurality of resonance frequencies Since the peak appears, the effect is remarkable.

On the other hand, in the above-described conventional manufacturing method, the square-shaped opening 4a of the silicon nitride film 4 is a mask patterned into the same size as the shape of the thin film beam portion 2 as already described. The silicon nitride films 4 and 5 are subjected to equal-magnification exposure by using, and the silicon nitride films 4 and 5 are photolithographically etched to pattern the silicon nitride films 4 and 5 according to the shape of the thin film beam portion 2. It was Therefore, the dimensional accuracy of the thin film beam portion 2 is determined by the accuracy of the mask, and it is difficult to improve the accuracy.

When manufacturing an LSI or the like, reduction projection is generally performed using a reduction projection exposure apparatus and photolithographic etching is performed. The manufacturing of the cantilever is also an application of semiconductor manufacturing technology, but the size of the square-shaped opening is, for example, about 4 μm, which is an order of magnitude larger than the size of the wiring pattern in the LSI of a tenth micron order. In the technical field of the cantilever, it was common technical knowledge to perform equal-magnification exposure. In fact, there have been no examples of using reduction projection exposure in the manufacture of cantilevers.

[0035]

EXAMPLES A method of manufacturing a cantilever for a scanning probe microscope according to an example of the present invention will be described below.

The cantilever manufactured by the manufacturing method according to this embodiment is basically the same as the cantilever shown in FIG. 1, and its manufacturing process is basically the same as the process shown in FIG. Therefore, FIGS. 1 and 2 will be referred to when describing the manufacturing method according to the present embodiment, and further, FIG. 3 will also be referred to. Therefore, FIG. 1 is also a view showing a cantilever manufactured by the manufacturing method according to the present embodiment, and FIG. 2 is also a schematic sectional view showing the manufacturing method according to the present embodiment.

In the manufacturing method according to this embodiment, first, a silicon single crystal substrate having a thickness of 250 μm and a (100) plane orientation is used as the silicon substrate 7, and the first inorganic material is formed on the silicon substrate 7 by vapor phase epitaxy. About 300n thick as material film
A silicon nitride film 4 of m is formed on the entire surface. Instead of the silicon nitride film 4, another inorganic material film such as a silicon oxide film may be formed.

After that, a square opening 4a exposing the surface of the silicon substrate 7 is formed at a predetermined portion of the silicon nitride film 4 (FIG. 2A). This opening 4a is formed by exposing the silicon nitride film 4 by reduction projection at the predetermined magnification using a reticle patterned in a square shape in which the shape of the opening 4a is enlarged by a predetermined magnification, and photolithographically etching the silicon nitride film 4. To form. For example, after the reduction projection exposure of the silicon nitride film 4 with a reduction projection exposure device (stepper) of 1/10 times using a reticle having a square pattern with a side of 40 μm ± 100 nm shown in FIG. , The silicon nitride film 4 is partially removed by dry etching, and the silicon nitride film 4 has a side of 4 μm as shown in FIG.
A square-shaped opening 4a of m ± 10 nm is formed.

Next, the substrate in the state shown in FIG.
The opening 4a of the silicon nitride film 4 is formed by immersing the silicon substrate 7 exposed in the anisotropic etching solution such as an H aqueous solution or a TMAH (tetramethylammonium hydroxide) aqueous solution in a square pyramid shape. A quadrangular pyramid-shaped trench 7a continuous with is formed in the silicon substrate 7 (FIG. 2B). Such a trench 7a is formed by utilizing the crystal orientation dependence of the etching rate.

After that, the exposed portion of the trench 7a of the substrate 7 is oxidized by a thermal oxidation method to form a silicon oxide film 8 in that portion (FIG. 2C). For example, FIG.
The substrate in the state shown in (b) is heated to 1000 ° C. in an oxygen atmosphere, and the portion of the trench 7a is oxidized for 2 hours to form the silicon oxide film 8.

Next, while leaving the silicon nitride film 4 on the substrate 7 in the state shown in FIG. 2C, a second inorganic material is formed so as to cover the surface of the silicon nitride film 4 and the surface of the silicon oxide film 8. A silicon nitride film 5 is formed as a material film to a thickness of about 300 nm by a vapor phase growth method or the like. The portion of the silicon nitride film 5 formed on the silicon oxide film 8 becomes the probe 3. The silicon nitride film 4 may be formed on the silicon substrate 7 and the silicon oxide film 8 after the silicon nitride film 4 on the substrate 7 in the state shown in FIG. 2B is removed by etching or the like. Instead of the silicon nitride film 5, another inorganic material film such as a silicon oxide film may be formed.

After that, the silicon nitride films 4 and 5 are patterned according to the shape of the thin film beam portion (lever) 2 (FIG. 2D). This patterning is performed, for example, by using a mask patterned to have the same size as the shape of the thin-film beam portion 2 (rectangular shape in this embodiment).
5 is exposed to the same size and the silicon nitride films 4 and 5 are photolithographically etched. Alternatively, in this patterning, the silicon nitride films 4 and 5 are exposed by reduction projection at the predetermined magnification using a reticle patterned to have a shape obtained by enlarging the shape of the thin film beam portion 2 at a predetermined magnification, and the silicon nitride film 4 is exposed. , 5 may be photolithographically etched. In this case, this patterning is performed, for example, by using a reticle having a pattern in which the shape of the thin film beam portion 2 is magnified 10 times and using a reduction projection exposure device (stepper) of 1/10 times the silicon nitride film. After reduction projection exposure of the films 4 and 5, dry etching is performed to partially remove the silicon nitride films 4 and 5.

Next, a member 6 such as a glass member is bonded onto the silicon nitride film 5 (FIG. 2 (e)).

Finally, the substrate in the state shown in FIG.
The silicon substrate 7 and the silicon oxide film 8 are immersed in an OH aqueous solution.
Are removed by etching. As a result, the cantilever shown in FIG. 1 is completed.

Cantilever probe 3 thus obtained
When a scanning electron micrograph of the above was taken, it was confirmed that the probe 3 had a tip radius of 10 nm and had no double tip. The same can be confirmed for many other cantilever probes 3 manufactured simultaneously using the same silicon substrate 7, and according to the manufacturing method of the present embodiment, a cantilever having a probe without double tips can be manufactured. It was confirmed that stable mass production was possible.

Further, in the above-mentioned manufacturing method, the reticle having a pattern in which the patterning of the silicon nitride films 4 and 5 in conformity with the shape of the thin film beam portion 2 is obtained by enlarging the shape of the thin film beam portion 10 times. By reducing projection exposure of the silicon nitride films 4 and 5 with a reduction projection exposure device (stepper) of 1/10 times, and then partially removing the silicon nitride films 4 and 5 by dry etching. The shape of the thin film beam portion 2 of the cantilever thus obtained was observed with a scanning electron microscope. As a result, the dimension of the thin film beam portion 2 was ± 10 nm with respect to the design value. Same silicon substrate 7
It is confirmed that the same applies to many other thin film beam portions 2 of cantilevers simultaneously manufactured by using, and in the manufacturing method according to the present embodiment, the thin film beam portions 2 of the cantilever are accurately processed with respect to the design value. It was confirmed that this is a possible manufacturing method. Therefore, according to the manufacturing method of the present embodiment, it is possible to stably manufacture a large number of cantilevers having a predetermined resonance frequency characteristic.

When this manufacturing method is used for manufacturing a cantilever as shown in FIG. 4 having a hollow-shaped thin film beam portion 2 used in a non-contact type atomic force microscope, the effect is particularly remarkable. large. The reason will be described below. In the non-contact type atomic force microscope, the cantilever is vibrated in the vicinity of the resonance frequency, and when the force is applied between the probe 3 and the sample, the resonance frequency shifts. Therefore, the shift amount is detected. By doing so, the sample surface shape is obtained. Therefore, when the cantilever is used in a non-contact type atomic force microscope, the thin film beam portion 2 of the cantilever is shown in FIG.
It is ideal to have a resonance frequency curve with a single peak as shown in. FIG. 4 is a perspective view showing another example of the cantilever. 4, constituent elements that are the same as or correspond to the constituent elements shown in FIG. 1 are assigned the same reference numerals, and descriptions thereof will be omitted. The cantilever shown in FIG. 4 is different from the cantilever shown in FIG. 1 in that the thin film beam 2 in the cantilever shown in FIG. 1 has a rectangular shape without a hollow portion, whereas in the cantilever shown in FIG. The only difference is that the portion 2 has a hollow shape (in this example, the thin film beam portion 2 has a triangular shape as a whole and further has a triangular hollow portion 20). In the cantilever shown in FIG. 4, even if the width dimensions a and b of the arms on both sides of the hollow portion 20 of the thin film beam portion 2 are slightly different, the mass of the arms on both sides is different.
As shown in FIG. 5B, two resonance frequency peaks appear in the resonance frequency curve of, and the resolution of the non-contact type atomic force microscope deteriorates. For this reason,
It is important that the dimensions of the cantilever be close to the design value.
Therefore, when the above-mentioned manufacturing method is used for manufacturing the cantilever as shown in FIG. 4 having the hollow thin film beam portion 2 used in the non-contact type atomic force microscope, its effect is particularly large. Of.

Next, a method of manufacturing a cantilever for a scanning probe microscope according to another embodiment of the present invention will be described with reference to FIG.
And FIG. 7 will be described.

FIG. 6 is a schematic perspective view showing a cantilever manufactured by the manufacturing method according to this embodiment. Figure 7
[FIG. 3] is a schematic cross-sectional view showing the manufacturing method according to the present embodiment.
In addition, in FIG. 7, the same or corresponding components as those in FIG. 6 are designated by the same reference numerals.

The cantilever shown in FIG.
A thin film beam portion (lever) 2 whose one end is supported by a support 1
And a probe 3 provided in the tip end side region of the thin film beam portion 2. In this cantilever, the thin film beam portion 2 is made of a silicon oxide film 21, and the probe 3 is made of silicon oxide integrated with the silicon oxide film 21. The silicon oxide film 21 extends not only to the portion of the thin film beam portion 2 but also to the portion of the support 1, and this portion of the silicon oxide film 21 and the silicon layer 22 constitute the support 1. The thin film beam portion 2 has a hollow shape.

In the manufacturing method according to this embodiment, first, (1
A thermal oxide film is grown to 1000 angstrom as a mask material 23 on a silicon substrate 22 having a (00) plane orientation. Next, after applying a photoresist 24, patterning is performed to form a spot having a diameter of 5 μm, and then SF ₆ and C ₂ are added.
Dry etching of silicon is performed using a mixed gas of ClF ₅ . At this time, the mask material 23 and the photoresist 24
Since the silicon underneath is etched, the lower part of the mask material 202 becomes columnar (FIG. 7A), but if etching is continued, side etching proceeds, and silicon in the shape of a needle is removed. Remain. At this point, etching is stopped and the photoresist 24 and the mask material 23 are removed (FIG. 7B). Next, the silicon surface is thermally oxidized. In this embodiment, the thermal oxide film (silicon oxide film) 21 is grown to about 1 μm (FIG. 7C).

Next, the thermal oxide film 21 is patterned according to the shape of the thin film beam portion 2. In this patterning, the silicon nitride films 4 and 5 are exposed by reduction projection at the predetermined magnification using a reticle patterned to have a shape obtained by enlarging the shape of the thin film beam portion 2 at a predetermined magnification, and the silicon nitride films 4 and 5 are exposed. By photolithographic etching.

Thereafter, the substrate in this state is anisotropically etched with KOH to remove a part of the silicon substrate 22.
As a result, the cantilever shown in FIG. 6 is completed.

Also in the manufacturing method according to this embodiment, since the thermal oxide film 21 is patterned according to the shape of the thin film beam portion 2 by reduction projection exposure, the cantilever having a predetermined resonance frequency characteristic is stabilized. And can be manufactured in large quantities.

Although the respective embodiments of the present invention have been described above, the present invention is not limited to these embodiments.

[0056]

As described above, according to the present invention, cantilevers having a probe without double tip can be stably manufactured in a large amount.

Further, it is possible to stably manufacture a large number of cantilevers having a predetermined resonance frequency characteristic.

[Brief description of drawings]

FIG. 1 is a view showing a cantilever manufactured by a manufacturing method according to an embodiment of the present invention and a conventional manufacturing method,
(A) is the perspective view, (b) is the II sectional view taken on the line in (a).

FIG. 2 is a schematic cross-sectional view showing a manufacturing method according to an embodiment of the present invention and a conventional manufacturing method.

FIG. 3 is an explanatory diagram illustrating a relationship between a square opening formed in a silicon nitride film and a reticle pattern.

FIG. 4 is a perspective view showing another example of a cantilever.

FIG. 5 is a diagram showing a resonance frequency curve of a thin film beam portion of a cantilever.

FIG. 6 is a perspective view showing a cantilever manufactured by a manufacturing method according to another embodiment of the present invention.

FIG. 7 is a schematic cross-sectional view showing a manufacturing method according to another embodiment of the present invention.

FIG. 8 is a perspective view showing a cantilever probe 3 manufactured by a conventional manufacturing method.

FIG. 9 is an explanatory diagram illustrating an influence of a double tip.

FIG. 10 is a diagram showing a cause of occurrence of double tip, (a) is a schematic plan view thereof, and (b) is A- in (a).
It is an A line schematic sectional drawing.

11A and 11B are other views showing the cause of the occurrence of the double tip, FIG. 11A is a schematic plan view thereof, and FIG. 11B is B in FIG. 11A.
It is a B-line schematic sectional drawing.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 support 2 thin film beam part 3 probe 4,5 silicon nitride film 4a square opening 6 glass member 7 silicon substrate 7a trench 8 silicon oxide film 21 thermal oxide film (silicon oxide film) 22 silicon layer (silicon substrate)

Claims (5)

[Claims] 1. A cantilever for a scanning probe microscope, comprising: a support; a thin film beam portion whose one end is supported by the support member; and a probe provided in a region on the tip end side of the thin film beam portion. A method of manufacturing, which comprises a step of forming a first inorganic material film on a silicon substrate, and a step of forming a square-shaped opening exposing a surface of the silicon substrate at a predetermined location of the first inorganic material film. And a step of etching a portion of the silicon substrate exposed from the opening in a cone shape to form a cone-shaped trench continuous with the opening of the inorganic material film in the silicon substrate, the trench of the silicon substrate Forming a silicon oxide film on the trench by oxidizing the first inorganic material film and the second inorganic film on the first inorganic material film and the silicon oxide film without removing the first inorganic material film. Material film Or forming a second inorganic material film on the silicon substrate and the silicon oxide film after removing the first inorganic material film, and the first and second inorganic materials. Patterning a film in conformity with the shape of the thin film beam portion; and removing the silicon substrate and the silicon oxide film in a portion corresponding to the thin film beam portion. In the step of forming, the reticle patterned into a square shape obtained by enlarging the shape of the square opening at a predetermined magnification is used to expose the first inorganic material film by reduction projection at the predetermined magnification, The square-shaped opening is formed by photolithographically etching the inorganic material film of No. 1. The method for manufacturing a cantilever for a scanning probe microscope, comprising: 2. The method of manufacturing a cantilever for a scanning probe microscope according to claim 1, wherein, in the step of forming the square-shaped opening, the reduction projection is performed using a reduction projection exposure device. 3. In the step of patterning the first and second inorganic material films according to the shape of the thin film beam portion, the thin film beam portion is patterned into a shape enlarged at a predetermined magnification. By using a reticle, the first and second inorganic material films are exposed by reduction projection at the predetermined magnification, and the first and second inorganic material films are photolithographically etched. The method of manufacturing a cantilever for a scanning probe microscope according to claim 1 or 2, wherein an inorganic material film is patterned according to the shape of the thin film beam portion. 4. A cantilever for a scanning probe microscope, comprising: a support; a thin film beam portion whose one end is supported by the support member; and a probe provided in a tip side region of the thin film beam portion. A method for manufacturing, comprising a step of patterning a thin film formed on a silicon layer according to the shape of the thin film beam portion, wherein in the step, the shape of the thin film beam portion is formed at a predetermined magnification. Using a reticle patterned in an enlarged shape,
Exposing the thin film by reduction projection at the predetermined magnification,
A method of manufacturing a cantilever for a scanning probe microscope, comprising: patterning the thin film according to the shape of the thin film beam portion by photolithographically etching the thin film. 5. The method for manufacturing a cantilever for a scanning probe microscope according to claim 3, wherein the thin film beam portion has a hollow shape.