JPH0396854A - Surface analysis probe - Google Patents

Abstract

PURPOSE:To accurately obtain magnetic force information and surface information by forming a flexible cantilever, forming a tip chip which is provided at the tip part of the cantilever slantingly to the surface of the cantilever and providing the probe stylus atop of the chip. CONSTITUTION:At the tip part of the cantilever 1, the chip 2 is formed slantingly at an angle theta to the surface of the cantilever. This chip 2 is formed slantingly in the opposite direction from a support 3 where the cantilever 1 is fixed and the tilt angle theta is selected within a range of 40 deg.<theta<70 deg. to the surface of the cantilever. Further, a metallic probe stylus 4 or magnetic probe stylus is formed at the tip part of the chip 2 formed atop of the cantilever 1. Consequently, the distance between a sample and the probe can accurately be controlled, so the magnetic force information and state information on the sample surface are obtained with high sensitivity and high resolution.

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to an apparatus that utilizes the magnetic force and tunneling current generated by bringing a probe and a sample, particularly a magnetic probe and a magnetic sample, close to each other. The present invention relates to a probe used in a scanning magnetic force microscope, a scanning tunneling microscope, an atomic force microscope, or a similar device suitable for obtaining information about the above. [Prior Art] A scanning tunneling microscope applies a voltage between a probe and a sample, and uses tunneling current and field emission current obtained when the probe and the sample are brought close to each other to determine the surface morphology of the sample. It is a device to investigate. A scanning magnetic force microscope is a device that uses a magnetic material as a probe and uses the magnetic force when the magnetic probe approaches a magnetic sample to examine the magnetization state of the sample. Conventionally, a method for acquiring magnetic information on a sample using a scanning magnetic force microscope that utilizes the magnetic force obtained by bringing a magnetic probe and sample close together is described in Journal of Vacuum Science and Technology A6 (1988) No. 279.
Pages 282 to 282, or Abrid Physics Letters Volume 50 (1987) No. 1455
Discussed on pages 1457-1457. In addition, regarding probes that detect the atomic force that occurs when a sample and a probe are brought close, see European Physics Letter 3 (1987), pp. 1281 to 1.
Page 286 (Europhys. Lett.
3 (1987) pp. 12 8 1-1
286).

[Problem to be solved by the invention]

A magnetic force microscope is a device that detects the magnetic force generated by the interaction between a leakage magnetic field on the surface of a magnetic sample and a magnetic probe. The magnetic probe used in the above-mentioned prior art has a structure in which the entire surface of a cantilever is coated with a magnetic material, or the tip of a magnetic wire is bent into an L-shape. In this case, the magnetic material attached to areas other than the tip of the magnetic probe disturbs the distribution of the leakage magnetic field on the sample surface, resulting in
There was a problem that the resolution of magnetic force information decreased. In another conventional technique, a magnetic probe is constructed by forming a magnetic needle at the tip of a planar cantilever in a direction perpendicular to the surface. In this case, in order to detect magnetic force information on the sample surface with high sensitivity, it is necessary to place the magnetic needle perpendicular to the sample surface, that is, to place the surface of the planar cantilever parallel to the sample surface. With this structure, for example, when measuring a sample with a large surface undulation, there are structural problems such as the sample colliding with the surface of the cantilever. 3 Furthermore, because conventional measurement methods do not measure magnetic force and surface morphology at the same time, errors occur due to changes in the gap between the probe and the sample, making it impossible to accurately measure magnetic force. . An object of the present invention is to provide a probe structure in which a metal probe or a magnetic probe provided at the tip of a cantilever can be easily installed so as to face perpendicularly to a sample surface.

[Means to solve the problem]

In order to achieve the above object, the present invention uses semiconductor ring graphing technology to form a flexible cantilever, and further forms a tip provided at the tip of the cantilever that is inclined to the surface of the cantilever. , a metal probe or magnetic probe is provided at the tip of this tip. The inclination θ of the distal tip portion with respect to the surface of the cantilever is preferably an angle of 40′<fJ<70°. [Function] The magnetic tip of the flexible cantilever also has a metal probe attached to the inclined tip at the tip of the cantilever, so the cantilever or its supporting member does not come into contact with the sample surface. The sample and magnetic probe can be placed sufficiently close to each other so that they are perpendicular to the sample surface. With this structure, a magnetic force depending on the magnetization state of the sample surface acts between the magnetic probe and the magnetic sample, thereby causing the probe, that is, the cantilever, to bend. Information on the magnetic force of the sample is obtained by detecting the amount of this deflection with a displacement detection means (for example, tunneling current, optical method, or change in capacitance) provided behind the cantilever. At the same time, by detecting the tunnel current between the sample and the magnetic probe, information on the surface morphology of the sample and more accurate magnetic force information can be obtained. In addition, it is possible to accurately trace the surface shape of objects to be measured, especially those with large surface undulations, and because only the tip of the probe can interact with the object, accurate magnetic force information and surface information can be obtained. . It is desirable to form it on the chip part. A similar measurement method uses a metal probe instead of a magnetic probe to detect the displacement between the sample and the probe due to acoustic, heat, light, etc. in addition to the magnetic force between the sample and the probe. Applicable to devices similar to type tunneling microscopes. In addition, by forming a coating layer on the surface of the magnetic probe,
This has the effect of preventing deterioration of the magnetic probe and keeping the magnetic properties of the magnetic probe stable for a long time. Desirable materials for this coating layer include Pt, Pd.
Au. Ru. Rl+. It is an alloy containing Cr and at least one element among these elements. Further, the desirable thickness of this coating layer is ↓OOnm or less. Further, as the material of the covering layer, a material having electrical conductivity is desirable. More preferably, a non-magnetic material is used. If the sample to be measured is a #4Am body or a material with low electrical conductivity, such as plastic or a coated magnetic disk, forming an electrically conductive coating layer on the surface of the measurement sample allows magnetic force information to be transferred to the surface. Morphological information can be obtained at the same time.

【Example】

The present invention will be explained below with reference to Examples. Example 1 This example will be explained with reference to FIG. A cantilever 1 having a sharp tip is manufactured using semiconductor lithography technology. The material for cantilever 1 is:
It is desirable to have high rigidity and low specific gravity. In this example, Si, Si○2, Si3N. Cantilevers 1 of similar structure were fabricated using , , and diamond-like carbon, and the same effects were obtained in both cases. At the tip of the cantilever 1, a tip 2 is formed which is inclined at an angle O with respect to the plane of the lever. The tilt angle θ of the chip 2 is formed by, for example, anisotropic etching using phosphorography technology, and can be arbitrarily changed by appropriately selecting the etching rate and etching solution. Further, this tip 2 preferably has a range of 40° and θ<70° with respect to the plane 7 in the direction opposite to the support 3 that fixes the cantilever king. Next, a metal probe 4 is formed at the tip of the tip 2 formed at the tip of the cantilever 1. As the metal probe 4, A.
u. Pt. Pd. Ru. A conductive material made of Re and an alloy containing Re is used. Further, the metal probe 4 may be formed into a magnetic probe by using a magnetic material. The metal probe 4 is formed by creating a resist pattern using a phosphorography technique, and then forming the metal probe 4 on this portion using a vacuum evaporation method or a sputtering method. Alternatively, a conductive material or a magnetic material may be selectively attached to this portion by electroplating. When a magnetic material is used as the metal probe 4, in order to provide anisotropy in the longitudinal direction of the tip 2, the length of the inclined portion of the tip 2 is larger than the width of the magnetic probe by a ratio of l or more. This is desirable. By chemically polishing the tip of the metal probe 4 formed in the above structure, it is possible to form a metal probe or a magnetic probe having a sharper tip with a curvature of 1000 degrees or less. Materials for the structure of the magnetic probe include permalloy including -880a t%Ni-Fe, Ni
．． Fe. An amorphous alloy containing Co or a Fe-C based material can be used. Example 2 An example of a method for manufacturing a metal probe and a magnetic probe will be explained with reference to FIG. A cante lever and a magnetic probe are manufactured using the semiconductor lithography technique shown in FIG. First, S of plane orientation (100)
A photoresist is applied to the surface of the substrate 21, exposed and developed using an exposure device, and a resist mask 22 is formed (FIG. 2a). Using this resist mask 22,
After anisotropically etching the Si substrate 21 with an alkaline aqueous solution such as KOH, the photoresist is removed to form a sloped portion 23 (FIG. 2b). Angle θ of this inclined portion 23
is 4 with respect to the Si substrate surface, that is, the cantilever surface 24.
0°〈θ×70° is suitable. Next, the Si substrate 21 is oxidized to form an oxide film 25 having a thickness of about 1.5 μm (FIG. 2C). Next, exposure and development are performed using an optical device to form a resist pattern 26 having the basic structure of a cantilever (FIG. 2d). Using this resist pattern 26 as a mask, the excess oxide film is etched using a mixed solution of hydrofluoric acid and ammonium fluoride solution to form a cantilever pattern 27, and the resist is removed (FIG. 2e). The tip of this cantilever pattern 27 is sharpened into a V-shape, as shown in FIG. 2J, and a tip 28 is formed in the area of the inclined portion 23. As a result, the basic structure of the chip is constructed as an integral structure that is inclined at an angle θ with respect to the cantilever. The value of θ is 40°<θ<70°. Next, a photoresist is applied on this cantilever pattern, exposed and developed using an exposure device, and an opening 29 is formed in a part of the area of the chip 28 (FIG. 2 f).
. A magnetic material 30 is attached to the opening 29 by vacuum evaporation or sputtering using a photoresist as a mask, and the resist is removed onto the photoresist 1 (FIG. 2g). Next, the cantilever pattern and the magnetic material part are protected with wax or the like, and the Si substrate 21 is etched with an alkaline aqueous solution such as KOH.
A magnetic probe 34 configured with a support base 33 is manufactured (FIG. 2h, FIG. 2k). Finally, a coating layer is formed on the surface of the magnetic probe. The material for this coating layer is Pt. Pd. Au, Cr.
Ru. Rh and materials containing these are preferable, and the thickness is desirably 100 nm or less. Furthermore, if the upper surface of the magnetic probe, that is, the lever surface forming the support base, is also made conductive, the displacement of the magnetic probe can be detected on this surface by scanning tunneling microscopy (STM) or the like. By using a non-magnetic metal material instead of the magnetic material 30, a metal probe consisting of a metal probe, a cantilever, and a support can be fabricated, which allows scanning tunneling microscopy (STM). Used as a probe for scanning atomic force microscopy. In this embodiment, the present invention was explained using a Si substrate with a plane orientation (↑00) of 11, but the same effect can be obtained by using a Si substrate with a plane orientation other than (100). Also, the Si substrate surface is O~ with respect to the plane orientation (1 0 0)
A substrate tilted within a range of 20° may also be used. Example 3 A magnetic force microscope was constructed using the magnetic probes produced according to Examples 1 and 2, and will be explained with reference to FIG. The magnetic probe is composed of a magnetic probe 31, a tip 28, a cantilever 32, and a support 33. The magnetic probe 31 formed at the tip of the magnetic probe is installed so as to contact the surface of the magnetic sample 35 perpendicularly. That is, the cantilever 32 is installed so that the tip at the tip is perpendicular to the sample surface. In this case, the support stand 33 is placed on the opposite side of the sample surface. In this magnetic probe, Au. A conductive film such as Pt is formed. A metal probe 36 with a sharp tip is installed behind the cantilever 32 and close to the surface 12 of the cantilever. The metal probe 36 is made of a W wire, a PT wire, or the like with a sharp tip. The measurement system configured as described above detects the displacement of the cantilever due to the leakage magnetic field on the surface of the magnetic sample 35, and from this result, magnetic force information such as the magnetic domain structure of the magnetic sample 35 is obtained. At the same time, by detecting the tunnel current between the magnetic probe 31 and the sample 35, information on the shape of the sample surface is obtained. By forming a coating layer on the surface of the magnetic probe, it is possible to perform measurements with good reproducibility even when operating for long periods in air, vacuum, or various gas atmospheres. In addition to permalloy alloy, Ni.
Fe. Go and alloys containing it, CoN b-Z r
．． Go-Mo-Z r. Go-T a-Z
r, or Fe/C. A similar effect can be obtained by using a Fe/permalloy multilayer film. As the coating layer, in addition to PT, Ru. Rh. The same effect can be obtained even if Au, Pd, and alloys containing these are used. [Effects of the Invention] As described above, the tip of the cantilever has a surface inclined with respect to the surface of the cantilever, forming a sharp tip, and a magnetic probe or a metal probe is formed on this tip. By placing this magnetic probe or metal probe perpendicularly close to the sample surface and using a magnetic force microscope, atomic force microscope, or similar equipment, the gap between the sample and the probe can be detected. Since the distance can be controlled with high precision, it is possible to obtain magnetic force information and morphology information on the sample surface with high sensitivity and high resolution. In addition, by coating the surface of the magnetic probe with a coating layer made of a conductive material, changes in magnetic properties and electrical conductivity due to oxidation of the surface of the magnetic probe can be prevented, and magnetic force information and sample surface morphology can be prevented. It has the effect of obtaining information with good reproducibility.

[Brief explanation of drawings]

FIG. 1 is an external perspective view of a surface analysis probe according to an embodiment of the present invention, FIG. 2 is a cross-sectional view and a plan view showing the manufacturing process of a magnetic probe according to an embodiment of the present invention, and FIG. 1 is a schematic perspective view of a main part of a magnetic force microscope using a magnetic probe according to an embodiment of the present invention. Explanation of symbols 1... Cantilever 2... Chip 3... Support body 4... Metal probe 21... Si substrate
22...Resist mask 23...Slope part
24... Cantilever surface 25... Oxide film
26...Resist pattern 27...Cantilever pattern 28...Chip 29...Opening 30...
・Magnetic material 31...Magnetic probe 32...Cantilever 33...Support stand 34...Magnetic probe
35...Magnetic sample 36...Metal probe

Claims (1)

[Scope of Claims] 1. A cantilever having flexibility, a support body integrally formed with the cantilever, and a tip integrally formed with the cantilever formed at the tip end thereof at a different angle from the cantilever surface. 1. A probe for surface analysis, characterized in that the probe has a tip, and a probe is formed at the tip of the tip. 2. The probe according to claim 1, wherein the cantilever is made of silicon oxide or silicon nitride. 3. In the probe according to claim 1 or 2, the inclination angle θ between the cantilever surface and the chip surface formed integrally therewith is
A probe for surface analysis, characterized in that the angle is inclined in the range of 40°<θ<70°. 4. A probe for surface analysis according to any one of claims 1 to 3, wherein the probe formed at the tip end is made of a magnetic material. 5. A method for measuring magnetic force using a magnetic force microscope and similar devices thereof, in which the probe according to any one of claims 1 to 4 is used, the axial direction of the probe being perpendicular to the sample surface;
Alternatively, a method for measuring magnetic force characterized by installing the magnetic force so as to face each other within a range of 40 to 90 degrees.