JPH10259092A - Formation of diamond pattern, probe for scanning probe device, and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a production method for forming diamond as a fine structure on a material different from the diamond in high productivity. SOLUTION: This method for forming diamond on a substrate comprises a step for forming a resist 9 on a substrate 5 having a core comprising a metal and a coating membrane formed on the core and comprising a nonmetal material, a step for removing the resist 9 at a part for forming the diamond 10, an etching step for removing the coated membrane 8 present at the resist- removed part, and a step for growing the diamond only at the part from which the coated membrane is removed in the substrate after finishing the etching step.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming diamond on fine parts. The present invention also relates to a method for manufacturing a probe of a scanning probe device for forming a diamond probe on a cantilever manufactured by using the method.

[0002]

2. Description of the Related Art A conductive probe is used in a scanning probe microscope for detecting the interaction between a probe and a surface and the tunnel current flowing between the probe and the surface to observe the fine shape of the surface. ing. Conventionally, a conductive probe (probe) has been manufactured by coating a silicon nitride substrate with a conductive metal thin film such as gold, or by processing a metal foil.

However, since the surface of a conductive probe manufactured by processing a metal foil is formed of a relatively soft material such as metal, the probe is deformed when the tip of the probe comes into contact with the sample surface. There is a disadvantage that it is worn out or worn. Also, conductive probes made by coating a conductive metal thin film such as gold,
Wear caused by contact between the tip of the probe and the sample surface
There is a serious disadvantage that the coated gold is exfoliated and the conductivity itself is lost.

Further, the spatial resolution of measurement and processing using a conductive probe largely depends on the shape of the probe tip, and if the tip is deformed or worn, the resolution may be significantly deteriorated. There was. To overcome these drawbacks, the probe tip must be made of a material with high wear resistance and conductivity. Doping by injection processing etc.,
This is a probe made of diamond with conductivity. In this method of manufacturing a probe having a cantilever, a diamond particle is manually adhered to the tip of the cantilever at the tip of the cantilever to obtain a probe provided with conductive diamond at a probe portion.

[0005] Incidentally, as a method of growing diamond, one of the methods is to artificially use microwave plasma CVD.
There is a method obtained by the vapor phase synthesis of diamond by the above method. In particular, as a report of growing a diamond film synthesized on a transition metal, the present inventors reported "Influence of transition metal on diamond synthesis by microwave plasma CVD" (Surface Technology Vol.44, No 10,1993 P47-P52) There is.

[0006]

However, as a method of providing diamond as one of the fine structures, a production method with high productivity has not been proposed at present, and furthermore, the diamond is provided with one end of a cantilever. There was no concrete example of a method of providing a high productivity in the country.

Therefore, the present invention proposes a production method with high productivity in which diamond is formed as a fine structure in a substance different from diamond. Further, the present invention proposes a method of efficiently providing a cantilever with a diamond probe tip for a probe used in a scanning probe device.

[0008]

According to a first aspect of the present invention, there is provided a method for forming diamond on a substrate, comprising: a sample comprising at least a metal; and a film comprising a non-metallic substance formed on the sample. A step of forming a resist on the substrate, a step of removing a resist in a portion where a diamond is formed among resists provided on the substrate, and an etching step of removing a film corresponding to a portion where the resist is removed; A diamond forming step of growing diamond only in a portion of the substrate after the etching step where the film is removed by a chemical vapor deposition method (CVD method) while introducing a gas having at least carbon atoms. did.

When it is desired to provide diamond as a fine structure, a lithographic technique using a resist can selectively expose a platinum-based transition metal on which diamond can easily grow. Diamonds can be attached only to parts. Also,
In the second embodiment of the present invention, in the forming method described in the first embodiment of the present invention, the coating may be formed of a substance made of an electric insulator. In the third and fourth aspects of the present invention, the coating is preferably made of an inorganic oxide ceramic. In particular, among inorganic ceramics, it is preferable to be made of silicon oxide.

In a fifth aspect of the present invention, it is preferable that the diamond is formed by a microwave plasma CVD method in the diamond forming step in the forming method described in the first aspect of the present invention. In the sixth embodiment of the present invention, in the diamond forming step, a gas containing a substance imparting conductivity is further introduced in the forming method described in the first embodiment of the present invention. By doing so, a fine structure having conductivity and excellent wear resistance can be obtained.

In a seventh aspect of the present invention, the metal provided in the sample is a platinum group metal. When diamond is grown by the chemical vapor deposition method, a platinum group metal is most preferable. According to an eighth aspect of the present invention, there is provided a process including a silicon substrate having a doping layer obtained by doping with a different substance, and a metal layer formed on the doping layer and made of a platinum-based transition metal. In a method of manufacturing a probe for a scanning probe device in which a probe is provided on an object, a step of forming a film made of a nonmetallic material on the object to be processed and a step of forming a resist film on the object on which the film is formed Forming, a step of removing a resist film corresponding to a portion where a probe is provided, an etching step of removing a film by etching a film in a portion where the resist film is removed, and a gas having at least carbon atoms. Chemical vapor deposition (CVD)
A process of forming a diamond film on the metal layer exposed in the etching process until the probe has a desired shape, and a process of processing the silicon substrate on which the probe has been formed into a desired shape. And As described above, as a method of manufacturing the probe of the scanning probe device, the lithography technique is used to partially expose the platinum-based transition metal,
By growing a diamond film by the CVD method, a diamond probe tip can be obtained only at a portion where a tip is to be formed.

It is particularly preferable as a method for manufacturing a probe for an atomic force microscope having a cantilever. Further, in the ninth embodiment of the present invention, in the probe forming step, a gas containing a substance for imparting conductivity is introduced to obtain a probe having conductivity and excellent wear resistance. be able to.

According to a tenth aspect of the present invention, there is provided a cantilever comprising a metal layer and a non-metal layer provided on one surface of the metal layer and having an opening at a portion where a probe is provided. In addition, a probe for a scanning probe microscope having a diamond probe having a substantially diamond structure in a portion where the probe is provided was used.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention has found a method for spatially selective vapor deposition of diamond in order to mass-produce diamond probes. We have developed diamond probe mass production technology that combines force microscope probe mass production technology.

First, the technique for selective vapor deposition of diamond performed in the embodiment of the present invention will be described with reference to FIG. In the embodiment of the present invention, first, a silicon substrate 1 on which a silicon oxide film 3 as a natural oxide film is formed is prepared, and a fine pattern made of a platinum group metal is formed on the natural oxide film of the silicon substrate 1. 2 is manufactured by a fine processing technique such as photolithography. Then, the silicon substrate 1 on which the fine pattern 2 is formed is placed in a chamber of a CVD apparatus, and is subjected to a chemical vapor deposition (CVD) method.
Grow diamonds by.

At this time, focusing on the fact that the growth rate of diamond is slower on the silicon oxide 3 than on platinum, the diamond fine pattern 4 was formed at the place where the fine pattern made of platinum group metal was formed. by the way,
Chemical vapor deposition using microwave plasma CVD
The law was applied.

Note that lutetium (Ru), rhodium (Rh), and iridium (Ir) have been confirmed as substances whose diamond growth rate is higher than that of silicon oxide. In this way, using a conventionally known lithography method, a metal film is formed only on the substrate covered with an oxide film so that the metal is exposed only at the place where a fine-shaped diamond is to be produced, and the chemical vapor phase is formed. By growing diamond while synthesizing it by a growth method, a fine diamond structure can be provided at a desired position on the substrate.

Further, in the embodiment of the present invention, a micro tip of diamond is attached to a cantilever by using a photolithography method, thereby manufacturing a tip for an atomic force microscope. A method of manufacturing the probe for the atomic force microscope will be described with reference to FIG. FIG. 2 is a diagram showing an example of a process for producing a probe for an atomic force microscope provided with a diamond probe according to the present invention.

First, a silicon substrate 5 having a <100> plane orientation is prepared. This silicon substrate 4 is doped with boron by an ion implantation method, and a boron doped layer 6 is formed on the outermost surface of the silicon substrate 5. Since the thickness of the boron-doped layer 6 corresponds to the finally obtained thickness of the cantilever, it is set according to the desired thickness of the cantilever. Then, a platinum (Pt) thin film 7 is formed by a sputtering method on the silicon substrate 5 on which the boron doped layer 6 is formed, and a silicon oxide film 8 is formed by a similar method. The silicon substrate 5 obtained in this manner is similar to that of FIG.
(A) of FIG.

Next, in order from the surface, a boron-doped layer 6 is formed.
A resist 9 is applied to the silicon substrate 5 on which the platinum thin film 7 and the silicon oxide film 8 are formed, and exposure is performed only at a position where a diamond probe is to be formed. Then, development is performed, and the resist 9 is dropped and patterned only at locations where diamond probes are to be formed. FIG. 2B shows the silicon substrate 5 thus obtained.

Next, using the patterned resist 9 as a mask, the silicon substrate 5 shown in FIG. 2B is immersed in a 50% hydrofluoric acid aqueous solution. Then, the silicon oxide film 8 not masked by the resist 9 is etched to pattern the silicon oxide film 8. Thereafter, the resist 9 remaining on the silicon oxide film 8 is entirely removed. The silicon substrate 5 thus obtained is
Only the desired portion has the platinum film 7 exposed, and FIG.
(C).

Next, the silicon substrate 5 shown in FIG.
Is placed in a microwave plasma CVD apparatus. Then, while supplying a methane gas and a hydrogen gas by the CVD method, a microwave is output to form a plasma atmosphere, and diamond can be grown in a portion where the platinum film 7 is exposed. FIG. 2D shows the silicon substrate 5 on which the diamond has been grown by the CVD method. FIG. 10 shows a diamond probe formed by the CVD method.

Next, a resist is applied to the silicon substrate 5 on which the diamond probe is formed, on the surface opposite to the side on which the diamond probe is formed. And
Exposure and development are performed to pattern the portion forming the support of the cantilever, and the resist 11 is left only in the portion forming the support of the cantilever (FIG. 3A).
reference).

Next, using the resist 11 as a mask, the silicon substrate 5 shown in FIG. 3A is immersed in a potassium hydroxide solution, and the surface of the silicon substrate 5 on which the diamond probe 10 is formed is removed. Performs anisotropic etching on the opposite surface. In this etching step, the etching ends at the boron doped layer 6. When the etching is completed sufficiently, the resist 11 is dropped to form the support portion 12 of the cantilever (see FIG. 3B).

The substrate thus obtained is finally cut into the shape shown in FIG. 3 (c) one by one, so that the atomic force at which the diamond probe 10 is provided on the cantilever portion 13 is obtained. A microscope probe could be fabricated. In this way, a plurality of atomic force microscope tips having diamond tips can be manufactured from a single silicon substrate, and diamond tips can be easily manufactured while improving mass productivity. You can now.

By the way, the diamond probe 1
When forming 0, a gas containing boron or the like (for example,
By introducing a gas containing diborane: B ₂ H ₆ ), the probe 10 can be made conductive. Further, since the probe 10 is directly bonded to the platinum thin film 7, by using the platinum thin film 7 as a wiring provided inside the cantilever portion 13, it can be used also as a probe of a scanning tunneling current microscope. Can be done. In addition, a resist that deteriorates by electric action is applied to a substrate to be finely processed, and an external power supply is connected between the probe manufactured in the embodiment of the present invention and the substrate to be finely processed. By performing this operation, the trajectory drawn by the probe can be processed on a substrate to be finely processed by a known lithography method. Thus, it can be used also as a probe used when performing fine processing by an electric action. Further, a highly durable fine probe for measuring electronic physical properties can be obtained.

Also, by forming a diamond probe so as to have conductivity and keeping the state shown in FIG. 2D, a microelectrode assembly such as a field emitter array can be manufactured. it can.

[0028]

Next, each step performed in the embodiment of the present invention will be described more specifically. First, in the CVD method performed in the step of synthesizing diamond and forming diamond on platinum 4 or platinum thin film 7, diamond synthesis was performed under the following conditions.

[0029]

[Table 1]

The platinum thin film 7 and the silicon oxide film 8 formed on the silicon substrate 5 have at least one thickness.
0 nm or more is preferable, and in this embodiment, it is 100 nm. The thickness of the boron-doped layer 5 is 1-6.
It does not matter if the range is about μm.

[0031]

According to the present invention, a diamond structure can be selectively provided only in a portion where a diamond structure is desired to be formed. Further, the diamond could be mounted on one end of the cantilever with high productivity.

[Brief description of the drawings]

FIG. 1 is a diagram showing a state in which diamond is selectively formed on a silicon substrate.

FIG. 2 is a view showing a manufacturing process of a probe for an atomic force microscope according to an embodiment of the present invention.

FIG. 3 is a view showing a manufacturing process of an atomic force microscope probe according to an embodiment of the present invention (continuation of FIG. 2).

[Explanation of symbols]

 1, 5 Silicon substrate 2, 7 Platinum thin film 3 Natural oxide film 4, 10 Diamond probe 6 Boron-doped layer 8 Silicon oxide film 9, 11 Resist 12 Cantilever support 13 Cantilever

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Matsufumi Takatani 3-22-13 Ojidai, Sakura City, Chiba Prefecture (72) Inventor Hiroyuki Sugimura 3-2-2 Marunouchi, Chiyoda-ku, Tokyo Nikon Corporation (72 ) Inventor Nobuyuki Nakagiri 3-2-3 Marunouchi, Chiyoda-ku, Tokyo Nikon Corporation

Claims (10)

[Claims] 1. A method for forming diamond on a substrate, comprising: forming a resist on a substrate having at least a sample including a metal and a coating made of a non-metallic material formed on the sample; Of the resist provided above, a step of removing the resist in a portion where the diamond is to be formed; an etching step of removing the film corresponding to the portion in which the resist has been removed; and introducing a gas having at least carbon atoms. Forming a diamond pattern by growing the diamond only in the portion of the substrate after the etching step where the film has been removed by chemical vapor deposition (CVD). Method 2. The method according to claim 1, wherein the coating is made of an electrically insulating material. 3. The method according to claim 1, wherein the coating is made of an inorganic oxide ceramic. 4. The method according to claim 3, wherein the coating is made of silicon oxide. 5. The diamond forming method according to claim 1, wherein said diamond forming step forms diamond by a microwave plasma CVD method. 6. The diamond forming method according to claim 1, wherein in the diamond forming step, a gas containing a substance for imparting conductivity is further introduced. 7. The diamond forming method according to claim 1, wherein the metal provided in the sample comprises a platinum group metal. 8. A probe is formed on a workpiece having a silicon substrate having a doping layer obtained by doping different substances and a metal layer formed on the doping layer and made of a platinum-based transition metal. In the method for manufacturing a probe for a scanning probe device provided, a step of forming a coating made of a non-metallic material on the workpiece, and forming a resist film on the workpiece on which the coating is formed A step of removing the resist film corresponding to a portion where the probe is to be provided; an etching step of removing the coating by etching the coating in the portion where the resist film is removed; and a gas having at least carbon atoms. Diamond is grown on the metal layer exposed in the etching step until a desired probe shape is formed by a chemical vapor deposition method (CVD method) performed by introduction. And the probe forming step that method of scanning probe device probe according to claim silicon substrate on which the probe is formed by performing a machining process for machining into a desired shape 9. The method of manufacturing a probe for a scanning probe device according to claim 8, wherein said probe forming step further comprises introducing a gas containing a substance for imparting conductivity. 10. A cantilever comprising a metal layer, a non-metal layer provided on one surface of the metal layer and having an opening at a portion where a probe is provided, and a portion provided with the probe And a probe for a scanning probe device having a diamond probe obtained by a vapor deposition method