JP2008185350A - Cantilever and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cantilever which shows good vibration characteristics in usual AFM measurement and can further perform cell operation by suppressing the damage applied to a cell to the utmost in the case used in the cell operation. <P>SOLUTION: The cantilever 10 has: a cantilever part 14 having a fixing end as the end fixed at a predetermined position and a free end as the end opposed to the fixing end; and the needle part 12 which is provided to the free end so as to form an angle with the cantilever part 14, having the first surface 12A on the side of the fixing end and the second surface 12B on the side opposite to the fixing end with respect to the first surface 12A where the first and second surfaces 12A and 12B are almost parallel to each other. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention is used in a scanning probe microscope apparatus that measures a local physical characteristic that acts between a sample and a needle part, and further provides a physical operation to the sample locally by the needle part. More particularly, the present invention relates to a cantilever that can be used in an operation device, in particular, a device that pierces a cell to form a micropore in a cell wall and introduces a substance such as a gene into the cell, and a method for manufacturing the same.

  In recent years, in the field of life science, in particular, in fields such as regenerative medicine and genome drug discovery, genes and drugs are injected into cells to modify the properties of the cells. By using such a technique, it is possible to elucidate the role of a gene and to make tailor-made medicine that performs treatment according to an individual's genetic characteristics.

  Conventionally, as a means for introducing a gene into a cell, an electroporation method, a particle gun method, a microinjection method, etc. are used as physical methods, and a calcium phosphate method is used as a method utilizing cell endocytosis. In addition, there are known methods such as the deroedextran method and the lipofection method. In addition, there are an infection method using a viral vector, a liposome method in which a liposome encapsulating a gene is introduced into a cell by cell fusion, and the like. However, the gene transfer by these methods is simply to keep the introduced gene in the cell constantly, for example, from the introduction of the gene to the expression, to the cell. It was not intended to observe in detail the kinetic changes that appear over time, and in fact, such observation was impossible.

  On the other hand, an atomic force microscope (AFM) is a scanning probe microscope that measures and detects an atomic force acting between materials. Analysis is possible with a force resolution of several pN level, and measurement applications are expanding to biomolecules, such as analyzing interactions between molecules such as peptides and proteins.

  In this AFM apparatus, a cantilever is used as a probe in which a very sharp needle with a radius of curvature of 5 to 50 nm is formed at the tip.

  Therefore, by using this AFM cantilever, it is possible to measure the physical properties and shape of the cell surface, inside and outside the cell, and to introduce the gene into the cell, collect the intracellular material, and perform other cell operations such as cell cutting. It is.

As the AFM cantilever, for example, a single crystal silicon cantilever having a tetrahedral needle portion at its tip as described in Patent Document 1 is commercially available. FIG. 7 is a schematic side view of the cantilever 100 having the tetrahedral needle portion. This cantilever is formed by forming a needle portion with two surfaces vertically processed by a dry etching technique and a surface 111 formed of a (111) surface exposed by an anisotropic wet etching technique. It is possible to form the needle portion 101 having an apex with a very stable radius of curvature at the portion. As a result, a stable AFM measurement is possible without the measurement site being shaded by the cantilever. In FIG. 7, reference numeral 103 denotes a support portion that supports the cantilever portion 102 that is a cantilever.
JP-A-8-262040

  In a normal cantilever that is commercially available, the surface of the cantilever is constituted by a (100) plane, and the angle formed with the (111) plane of the needle portion is about 55 degrees, which is the angle between each plane of single crystal silicon. It has become. Accordingly, the width of the side surface of the needle part is about 7 μm of 10 / tan (55 °) at a position of 10 μm from the needle apex.

  As described in the above-mentioned Patent Document 1, the length of the cantilever surface can be slightly reduced by using a crystal plane cut by tilting the cantilever surface from the (100) plane. If used, the wet etching process in forming the needle portion 101 causes problems such as formation of protrusions on the cantilever surface, so that the tip apex angle is limited to about 60 degrees at most, and even in this case, 10 μm from the needle apex. The side width of the needle part at 5.8 is 5.8 μm.

  In measurement with a normal atomic force microscope or molecular force microscope, the sharpness of the tip of the needle is important because it affects the accuracy of the measurement, and is emphasized. On the other hand, especially in applications where a sample is placed in a liquid, such as a biological sample, a method (AC mode) is often used that detects the interaction between the sample and the needle from the vibration characteristics of the cantilever. Therefore, the vibration characteristics of the cantilever are important. In a conventional cantilever, a needle portion having a large volume, that is, a large weight is formed on the free end side of the soft lever portion, so that it does not necessarily have good vibration characteristics, and particularly in liquid, vibration does not occur. Since it is greatly attenuated and the detection signal becomes weak, it is desired to further improve the vibration characteristics.

  In some cases, the above-mentioned cantilever is used to insert a needle into a cell and perform cell manipulation such as gene transfer and measurement inside the cell. However, if the length of about 10 μm inserted into the cell is not uniformly thin, the cell will die due to the insertion damage. If a cantilever for measurement with a normal atomic force microscope or the like is used as it is, the cell will be damaged. Will become bigger. For this reason, it is important to reduce the volume of the entire needle portion.

  The present invention has been made in view of the above points, and exhibits good vibration characteristics in normal AFM measurement, and further can perform cell manipulation and intracellular measurement while suppressing damage to cells as much as possible. It is an object to provide a highly cantilever and a method for producing the same.

One aspect of the cantilever of the present invention is
A cantilever beam having a fixed end as an end fixed at a predetermined position and a free end as an end opposite to the fixed end;
The first end is provided at the free end at an angle with the cantilever and has a first surface on the fixed end side and a second surface opposite to the fixed end with respect to the first surface. A needle portion in which one surface and the second surface are substantially parallel;
It is characterized by having.

One aspect of the method for producing a cantilever of the present invention is as follows.
Forming a cantilever beam having a fixed end and a free end fixed in place;
Forming a second surface substantially parallel to the first surface on the fixed end side on the needle portion provided at the free end at an angle with the cantilever;
It is characterized by having.

  According to the present invention, since the first surface and the second surface of the needle portion are substantially parallel and can be further thinned, it exhibits good vibration characteristics in normal AFM measurement, and is further used for cell manipulation. In this case, it is possible to provide a cantilever capable of performing cell manipulation and intracellular measurement while suppressing damage to cells as much as possible, and a method for producing the cantilever.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

[First Embodiment]
1A and 1B are views showing the configuration of the first embodiment of the cantilever of the present invention. In particular, FIG. 1A is a sectional view thereof, and FIG. 1B is a perspective view thereof. .

  The cantilever 10 according to the present embodiment includes a needle portion 12, a cantilever portion 14, and a support portion 16. The needle portion 12 is made of single crystal silicon, is formed at the free end of the cantilever portion 14 that is a cantilever, and protrudes from the surface of the cantilever portion 14 in the direction opposite to the support portion 16. The first surface 12A on the fixed end side of the needle portion 12 to the support portion 16 of the cantilever portion 14 and the second surface 12B on the opposite side to the fixed end with respect to the first surface 12A are substantially parallel. Is formed.

  2A and 2B are diagrams for explaining the difference in cross section between the needle portion 101 of the conventional AFM cantilever disclosed in Patent Document 1 and the needle portion 12 of the cantilever 10 according to the present embodiment. It is the figure which showed each cross-sectional shape.

  The cross section of the needle portion 12 of the cantilever 10 according to the present embodiment is obtained by partially removing the needle portion 101 in parallel with the surface 111 formed of the (111) surface in the conventional AFM cantilever needle portion 101. It narrows uniformly from the apex toward the needle base.

  On the other hand, the cantilever portion 14 is preferably single crystal silicon having a (100) plane on the lever surface, but may be a single crystal silicon having a plane shifted from the (100) plane as disclosed in Patent Document 1 above. A silicon nitride film, a polysilicon film, an amorphous silicon film, or the like may be used.

  The support portion 16 is also preferably made of single crystal silicon, but glass or the like may be used.

  Next, as a cell introduction needle according to the present embodiment, a manufacturing method in which the needle part 12, the cantilever part 14, and the support part 16 are all formed of single crystal silicon is shown in the manufacturing process diagrams shown in FIGS. This will be explained based on.

  First, as shown in FIG. 3A, after forming a silicon oxide film 20 on the surface of a silicon wafer 18 having a plane orientation (100) as a start substrate, for example, a silicon wafer 22 having an n-type plane orientation (100) is formed. A bonded substrate, a so-called bonded SOI (Silicon On Insulator) substrate is used. Here, the silicon wafer 22 forms the cantilever part 14 and the needle part 12, and the thickness thereof is set in accordance with the required characteristics. For example, the thickness is about 20 μm.

  Next, as shown in FIG. 3B, a mask pattern 24 for forming the support portion 16 is formed on the back surface of the SOI substrate using silicon oxide, silicon nitride, or the like. Thereafter, a cantilever-forming photoresist pattern is formed on the SOI substrate surface using a mask 28 having a V-shaped protrusion 26 as shown in FIG. 4, and then silicon oxide is formed using RIE (Reactive Ion Etching) or the like. By etching the silicon wafer 22 substantially vertically until the film 20 is exposed, a cantilever pattern 30 having a V-shaped tip is formed, and a silicon oxide film 32 is formed only on the side wall of the cantilever pattern 30. As a method of forming the silicon oxide film 32 only on the side wall, for example, the entire surface of the cantilever pattern 30 may be oxidized, and then the silicon oxide film 32 on the surface may be etched by RIE. Alternatively, a silicon nitride film may be formed on the surface of the cantilever pattern 30 in advance, and the silicon nitride film on the surface may be removed after the oxidation treatment.

  Next, as shown in FIG. 3 (C), the surface of the cantilever pattern 30 is wet anisotropic with an aqueous alkaline solution such as potassium hydroxide (KOH), ethylenediamine / pyrocatechol (EDP), tetramethylammonium hydroxide (TMAH), or the like. The tetrahedral needle 34 is formed at the tip of the cantilever pattern 30 by performing etching. The formation principle of the tetrahedral needle part 34 is that, when wet anisotropic etching is performed with the side surfaces masked by the silicon oxide film 32, the etching speed of the (111) crystal plane is remarkably slow. This is because the etching is almost stopped at the time of exposure. In order to leave the cantilever part 14, the wet etching is stopped so that the required thickness of the cantilever remains before the silicon oxide film 20 is exposed. Thereafter, the silicon oxide film 32 is removed with a hydrofluoric acid aqueous solution. After that, if necessary, a cantilever pattern shape may be changed to an optimum one by forming a resist pattern on the surface and etching the cantilever pattern again. Moreover, in order to make the needle part 12 thinner, the surface may be oxidized at a temperature of 950 ° C. or lower.

  Next, as shown in FIG. 3D, after the surface is protected with a silicon oxide film or the like, wet etching with an alkaline aqueous solution is performed on the back surface of the substrate until the silicon oxide film 20 is exposed, and finally an aqueous hydrofluoric acid solution is used. By removing the silicon oxide film 20, the cantilever 100 composed of the silicon support part 16 and the cantilever part 14 and the tetrahedral needle part 34 similar to the conventional one can be obtained.

  Further, in this embodiment, each cantilever 100 is then cut off from the substrate formed in a lump, and as shown in FIG. 3E, for example, each of the cantilevers 100 is used by using a FIB (Focused Ion Bram) apparatus or the like. By etching and processing the second surface 34B opposite to the first surface 34A, which is the exposed (111) surface of the tetrahedral needle portion 34, in parallel with the first surface 34A, ( A needle portion 12 having a first surface 12A that is a (111) surface and a second surface 12B parallel to the first surface 12A is obtained. Here, 34A and 12A are the same surface.

  Although it is possible to form the thin needle portion 12 by performing etching parallel to the tip ridge portion of the tetrahedral needle portion 34, in this case, in order to leave a portion that supports the needle, a processing region is designated vertically. There must be. On the other hand, when the removal processing part is specified in parallel to the exposed (111) plane, the processing region may be specified in a straight line, so that the setting to the processing apparatus is easy and inexpensive. It becomes possible to provide.

  In addition, since single crystal silicon is used, the angle between the lever surface and the (111) surface is regulated to approximately 125 degrees, so that it is possible to always produce the needle portion 12 having a constant shape. The cantilever 10 having the needle portion 12 with stable characteristics can be provided.

  According to the present embodiment, the side width of the needle portion 12 at 10 μm from the needle apex can be 1 μm or less. Therefore, a cantilever 10 that exhibits good vibration characteristics even in normal AFM measurement, and can perform cell manipulation and intracellular measurement while suppressing damage to cells as much as possible when used in cell manipulation, and A manufacturing method thereof can be provided.

[Second Embodiment]
Next, a second embodiment of the cantilever according to the present invention will be described with reference to the manufacturing process diagrams shown in FIGS.

  Also in this embodiment, the tetrahedral needle portion 34 is formed at the tip of the cantilever pattern 30 in the same manner as described with reference to FIGS. 3A to 3C in the first embodiment.

  Thereafter, in the first embodiment, the silicon oxide film 32 formed on the side wall of the cantilever pattern 30 is immediately peeled and removed. However, in this embodiment, as shown in FIG. With the silicon oxide film 32 left, a p-type impurity such as boron is introduced from the surface of the cantilever pattern 30. Since the side wall of the cantilever pattern 30 is covered with the silicon oxide film 32, the p-type impurity 36 is introduced and diffused only on the cantilever surface and the (111) exposed surface of the tetrahedral needle portion 34.

  Next, as shown in FIG. 5B, after the sidewall silicon oxide film 32 is removed with an aqueous hydrofluoric acid solution, wet anisotropic etching with an aqueous alkali solution such as KOH, EDP, TMAH is performed for a short time. It is known that the etching rate of wet anisotropic etching with an alkaline aqueous solution is remarkably reduced by diffusing high-concentration p-type impurities into a silicon substrate. In this step, the cantilever pattern 30 and the tetrahedral needle portion 34 are exposed to the alkaline aqueous solution, but the surface of the cantilever pattern 30 is hardly etched because the high-concentration p-type impurity 36 is diffused. Further, the (111) exposed surface of the tetrahedral needle portion 34 is originally not etched because the etching rate with respect to the alkaline aqueous solution is slow and the high-concentration p-type impurity 36 is diffused, and becomes the tip ridge portion of the needle portion 12. Etching proceeds from a portion where the p-type impurity 36 on the side surface of the needle portion 12 is not diffused. As a result, only the portion where the high-concentration p-type impurity 36 is diffused in parallel to the (111) exposed surface of the tetrahedral needle portion 34 remains as the needle portion 12.

  Thereafter, as in the first embodiment, as shown in FIG. 5C, after the surface is protected with a silicon oxide film or the like, wet etching with an alkaline aqueous solution is performed on the back surface of the SOI substrate until the silicon oxide film 20 is exposed. And finally, the silicon oxide film 20 is removed with an aqueous hydrofluoric acid solution, so that the silicon support part 16 and the cantilever part 14 and the parallel (111) plane are formed to be extremely thin from the tip to the base part. A cantilever 38 configured with the needle portion 12 having the first and second surfaces 12A and 12B is obtained.

  According to the present embodiment, the cantilever 38 having the thin needle portion 12 that does not damage the cells can be formed in a lump, so that mass production is possible and it can be provided at a very low cost. .

  In this embodiment, the fact that the etching rate of the p-type impurity diffusion layer is reduced by diffusing the p-type impurity 36 in the n-type silicon wafer 22 is used. However, the n-type impurity is introduced into the p-type silicon substrate. After introducing and diffusing, the etching rate of the n-type impurity diffusion layer can be reduced by etching with an alkaline aqueous solution while applying a potential to the etching surface. Absent.

[Third Embodiment]
Next, a third embodiment of the cantilever according to the present invention will be described based on the manufacturing process diagrams shown in FIGS.

  In this embodiment, first, as shown in FIG. 6A, a silicon oxide film 20 is formed on the surface of a silicon wafer 18 having a plane orientation (100) as a start substrate.

  Next, for example, a V-shaped groove 40 is formed in the vicinity of a region where the needle part 12 is to be formed on the n-type surface orientation (100) of the silicon wafer 22 by alkali anisotropic wet etching. The formation position of the V-shaped groove 40 is such that the tip of the cantilever pattern 30 having the V-shaped tip explained in the first and second embodiments is in front of the groove bottom ridge portion of the V-shaped groove 40. And the depth is formed deeper than the length of the needle portion 12.

  Note that after the V-shaped groove 40 is formed, the surface of the V-shaped groove 40 may be oxidized to cover the surface with an oxide film layer. By doing so, it is possible to prevent problems such as roughening of the surface of the V-shaped groove 40 due to the RIE process when the cantilever pattern 30 is formed.

  Thereafter, the SOI substrate having the V-shaped groove 40 inside is manufactured by bonding the silicon wafer 22 to the silicon wafer 18 with the V-shaped groove 40 opening side being the silicon wafer 18 side. It is to be noted that when the bonding process for manufacturing the SOI substrate is performed in a vacuum chamber so that air does not enter the V-shaped groove 40, the SOI substrate may be ruptured during the subsequent heat treatment process. You can prevent problems.

  Next, as shown in FIG. 6B, a mask pattern 24 for forming the support 16 on the back surface of the SOI substrate is formed of silicon oxide or the like. Thereafter, a photoresist pattern for cantilever formation is formed on the SOI substrate surface using a mask 28 having a V-shaped protrusion 26, and then the silicon wafer 22 is formed until the silicon oxide film 20 is exposed using RIE or the like. By etching almost vertically, a cantilever pattern 30 having a V-shaped tip is formed, and a silicon oxide film 32 is formed only on the side wall of the cantilever pattern 30.

  Next, as shown in FIG. 6C, the needle part 12 is formed at the tip of the cantilever pattern 30 by performing wet anisotropic etching with an alkaline aqueous solution on the surface of the cantilever pattern 30. Unlike the cases shown in the first and second embodiments described above, since the tip ridge line portion of the needle portion 12 is cut in advance, the needle portion 12 has a first surface 12A composed of parallel (111) surfaces and a second surface. The shape is sandwiched between the surfaces 12B. Therefore, the thickness of the needle can be controlled by controlling the formation position of the cantilever pattern 30 and the etching amount when the needle portion 12 is formed. Thereafter, the silicon oxide film 32 is removed with a hydrofluoric acid aqueous solution. Moreover, in order to make the needle part 12 thinner, the surface may be oxidized.

  Next, as shown in FIG. 6D, after the surface is protected with a silicon oxide film or the like, wet etching with an alkaline aqueous solution is performed on the back surface of the SOI substrate until the silicon oxide film 20 is exposed, and finally hydrofluoric acid is used. By removing the silicon oxide film 20 with an aqueous solution, the cantilever 10 including the silicon support portion 16 and the cantilever portion 14 and the needle portion 12 having the first and second surfaces 12A and 12B is obtained.

  Also according to the present embodiment, the cantilever 10 having the thin needle portion 12 that does not damage the cells can be collectively formed, so that mass production is possible and it can be provided at a very low cost.

  Although the present invention has been described above based on the embodiments, the present invention is not limited to the above-described embodiments, and various modifications and applications are naturally possible within the scope of the gist of the present invention.

(Appendix)
The invention having the following configuration can be extracted from the specific embodiment.

(1) a cantilever having a fixed end as an end fixed at a predetermined position and a free end as an end opposite to the fixed end;
The first end is provided at the free end at an angle with the cantilever and has a first surface on the fixed end side and a second surface opposite to the fixed end with respect to the first surface. A needle portion in which one surface and the second surface are substantially parallel;
A cantilever characterized by comprising:

(Corresponding embodiment)
The embodiment relating to the cantilever described in (1) corresponds to the first to third embodiments. In these embodiments, the cantilever portion 14 is the cantilever, the first surface 12A is the first surface, the second surface 12B is the second surface, the needle portion 12 is the needle portion, the cantilever 10, 38 corresponds to the cantilever.

(Function and effect)
According to the cantilever described in (1), since it has a thin needle portion, the weight of the needle portion is small, and good vibration characteristics can be obtained in AFM measurement.

  (2) The cantilever according to (1), wherein the needle part is a part to be inserted into the cell.

(Corresponding embodiment)
The embodiment relating to the cantilever described in (2) corresponds to the first to third embodiments.

(Function and effect)
According to the cantilever described in (2), cell manipulation and intracellular measurement can be performed without damaging the cell, particularly by being inserted into the cell.

  (3) The cantilever according to (1), wherein the needle part is formed by cutting the free end of the cantilever leaving a portion to be inserted into the cell.

(Corresponding embodiment)
The embodiment relating to the cantilever described in (3) corresponds to the first embodiment.

(Function and effect)
According to the cantilever described in (3), since it is only necessary to designate the machining area in a straight line, the setting to the machining apparatus is easy, and it can be provided at low cost.

  (4) The cantilever according to (1), wherein the needle portion is made of single crystal silicon.

(Corresponding embodiment)
The embodiment relating to the cantilever described in (4) corresponds to the first to third embodiments.

(Function and effect)
According to the cantilever described in (4), a cantilever having a needle portion with stable characteristics can be provided.

  (5) The cantilever according to (4), wherein the first surface formed on the needle part is a (111) surface.

(Corresponding embodiment)
The first to third embodiments correspond to the cantilever embodiment described in (5).

(Function and effect)
According to the cantilever described in (5), since the angle between the lever surface and the (111) surface is regulated to approximately 125 degrees, it is possible to always produce a needle portion having a fixed shape.

  (6) The cantilever according to (1), wherein the needle portion has a different impurity concentration from the back surface of the surface on which the needle portion of the cantilever is formed.

(Corresponding embodiment)
The embodiment relating to the cantilever described in (6) corresponds to the second embodiment.

(Function and effect)
According to the cantilever described in (6), it is possible to collectively form cantilevers having a thin needle portion that does not damage cells, so that mass production is possible and it can be provided at a very low cost. It becomes possible.

(7) forming a cantilever beam having a fixed end and a free end fixed at a predetermined position;
Forming a second surface substantially parallel to the first surface on the fixed end side on the needle portion provided at the free end at an angle with the cantilever;
A method for producing a cantilever, comprising:

(Corresponding embodiment)
The first to third embodiments correspond to the cantilever manufacturing method described in (7). In these embodiments, the cantilever portion 14 is the cantilever, the needle portion 12 is the needle portion, the first surface 12A is the first surface, the second surface 12B is the second surface, 38 corresponds to the cantilever.

(Function and effect)
According to the cantilever manufacturing method described in (7), a cantilever having a thin needle portion that does not damage cells can be manufactured.

  (8) The method for manufacturing a cantilever according to (7), wherein the step of forming the second surface is performed after the step of forming the cantilever.

(Corresponding embodiment)
The embodiment relating to the cantilever manufacturing method described in (8) corresponds to the first embodiment.

(Function and effect)
According to the method for manufacturing a cantilever described in (8), it is only necessary to designate a machining area in a straight line after forming a cantilever beam. Is possible.

  (9) The method for manufacturing a cantilever according to (7), wherein the step of forming the second surface is performed in advance before the step of forming the cantilever.

(Corresponding embodiment)
The third embodiment corresponds to the cantilever manufacturing method described in (9).

(Function and effect)
According to the cantilever manufacturing method described in (9), it is possible to control the thickness of the needle portion by forming the second surface first, and the thin needle that does not damage the cells Since cantilevers having a portion can be formed in a lump, mass production is possible and it can be provided at a very low cost.

  (10) The method for manufacturing a cantilever according to (7), wherein the step of forming the second surface is performed in parallel with the step of forming the cantilever.

(Corresponding embodiment)
The second embodiment corresponds to the cantilever manufacturing method described in (10).

(Function and effect)
According to the method for producing a cantilever described in (10), it is possible to form cantilevers having a thin needle portion that does not damage cells, so that mass production is possible and it is provided at an extremely low cost. It becomes possible to do.

  (11) The method for manufacturing a cantilever according to (10), wherein the step of forming the second surface is a step of etching at a different rate from the step of forming the cantilever.

(Corresponding embodiment)
The second embodiment corresponds to the cantilever manufacturing method described in (11).

(Function and effect)
According to the method for manufacturing a cantilever described in (11), it is possible to easily perform the parallel execution of the step of forming the second surface and the step of forming the cantilever by using the difference in etching rate. it can.

FIG. 1A is a cross-sectional view showing the configuration of the cantilever according to the first embodiment of the present invention, and FIG. 1B is a perspective view of the cantilever. FIG. 2A is a diagram illustrating a cross-sectional shape of a needle portion of a conventional AFM cantilever, and FIG. 2B is a diagram illustrating a cross-sectional shape of the needle portion of the cantilever according to the first embodiment. FIG. 3 is a manufacturing process diagram for explaining the manufacturing method of the cantilever according to the first embodiment of the present invention. FIG. 4 is a view showing a mask having a V-shaped protrusion used in the manufacturing method shown in FIG. FIG. 5 is a manufacturing process diagram for explaining a manufacturing method of a cantilever according to the second embodiment of the present invention. FIG. 6 is a manufacturing process diagram for explaining a manufacturing method of a cantilever according to a third embodiment of the present invention. FIG. 7 is a schematic side view of a cantilever having a conventional tetrahedral needle portion.

Explanation of symbols

    10, 38, 100 ... cantilever, 12 ... needle portion, 12A, 34A ... first surface, 12B, 34B ... second surface, 14 ... cantilever portion, 16 ... support portion, 18, 22 ... silicon wafer, 20, 32 ... Silicon oxide film, 24 ... Mask pattern, 26 ... V-shaped protrusion, 28 ... Mask, 30 ... Cantilever pattern, 34 ... Tetrahedral needle, 36 ... P-type impurity, 40 ... V-shaped groove.

Claims (11)

A cantilever beam having a fixed end as an end fixed at a predetermined position and a free end as an end opposite to the fixed end;
The first end is provided at the free end at an angle with the cantilever and has a first surface on the fixed end side and a second surface opposite to the fixed end with respect to the first surface. A needle portion in which one surface and the second surface are substantially parallel;
A cantilever characterized by comprising:   The cantilever according to claim 1, wherein the needle part is a part to be inserted into the cell.   2. The cantilever according to claim 1, wherein the needle portion is formed by cutting the free end of the cantilever leaving a portion to be inserted into the cell.   The cantilever according to claim 1, wherein the needle portion is made of single crystal silicon.   The cantilever according to claim 4, wherein the first surface formed on the needle portion is a (111) surface.   2. The cantilever according to claim 1, wherein the needle portion has a different impurity concentration from a back surface of the surface of the cantilever on which the needle portion is formed. Forming a cantilever beam having a fixed end and a free end fixed in place;
Forming a second surface substantially parallel to the first surface on the fixed end side on the needle portion provided at the free end at an angle with the cantilever;
A method for producing a cantilever, comprising:   The method of manufacturing a cantilever according to claim 7, wherein the step of forming the second surface is performed after the step of forming the cantilever.   The method of manufacturing a cantilever according to claim 7, wherein the step of forming the second surface is performed in advance before the step of forming the cantilever.   The method of manufacturing a cantilever according to claim 7, wherein the step of forming the second surface is performed in parallel with the step of forming the cantilever.   The method of manufacturing a cantilever according to claim 10, wherein the step of forming the second surface is a step of etching at a different rate from the step of forming the cantilever.

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