JP3222410B2 - Cantilever unit, its holder, and scanning probe microscope equipped therewith - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cantilever unit having a self-sensing cantilever for outputting an electric signal in response to the amount of deflection of the cantilever, a holder thereof, and a scanning probe microscope equipped with the same. The present invention relates to a cantilever unit, a holder thereof, and a scanning probe microscope equipped with the same, in which a detection type cantilever can be easily and accurately mounted.

[0002]

2. Description of the Related Art In a scanning probe microscope such as an AFM,
A cantilever having a probe attached to the tip of a cantilever is used as a probe in order to detect a fine structure or structure on the sample surface by utilizing the interaction between the sample surface and the probe. Since an attractive force or a repulsive force based on the atomic force is generated between the sample surface and the probe, the probe is moved XY on the sample surface.
While scanning in the direction, the atomic force is detected as the amount of strain of the cantilever, and if the sample stage is finely moved in the Z-axis direction so that the amount of this strain, that is, the gap between the sample surface and the probe, becomes constant, The fine movement signal or the detected distortion amount itself represents the shape of the sample surface.

FIG. 13 is a diagram schematically showing the structure of a cantilever portion of a conventional scanning probe microscope. A probe attached to a free end of a cantilever 63 is provided above a sample 64 to be observed. 65 are arranged facing each other.
The laser light 66a emitted from the laser generator 61 is converged by a suitable lens means 67 or an aperture or the like, and is irradiated on the back surface near the free end of the cantilever 63. The amount of deflection of the cantilever 63 is detected by measuring the spot position of the reflected laser beam 66b with the position detector 62.

The position detector 62 is composed of, for example, four divided light detection electrodes. When the amount of deflection of the cantilever 63 is zero, the position of the laser beam 66b is adjusted so as to come to the center of the four divided electrodes. Have been. Therefore, when the cantilever 63 is bent, the spot of the laser beam 66b moves on the four-divided electrode, and a difference is generated in the voltage output from the four-divided electrode.

[0005]

As described above, the method of optically detecting the amount of deflection of the cantilever has a problem that the configuration is complicated and adjustment is difficult. Therefore, in recent years, a self-detecting cantilever has been developed, which has a feature in which a sensor function for detecting the amount of bending is provided on the cantilever and the detected amount of bending can be directly output as an electric signal.

According to such a self-detecting cantilever, an expensive optical system and complicated adjustment are not required, but on the other hand, an electric contact provided on the cantilever side for outputting an electric signal and a cantilever are used. It is necessary to accurately position and fix the cantilever with respect to the holder so that the electrical contact of the holder provided on the scanning probe microscope side for holding accurately contacts the holder.

On the other hand, since the average replacement frequency of the cantilever is once / day, it is desirable to hold the cantilever so that it can be easily attached to and detached from the holder. However, until now, self-detecting cantilevers used for scanning probe microscopes have not been widespread, and there has been no cantilever holder that can easily and accurately mount the cantilever.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of the prior art and to provide a cantilever unit for easily and accurately mounting a self-detecting cantilever, a holder for holding the cantilever unit, and these. An object of the present invention is to provide a scanning probe microscope equipped with a scanning probe microscope.

[0009]

Means for Solving the Problems In order to achieve the above object, the present invention is characterized in that the following means are taken. (1) A cantilever unit of the present invention includes a self-detecting cantilever, a substrate holding the self-detecting cantilever, and a plurality of contact patterns electrically connected to the detection unit and formed on a substrate surface. And a plurality of contact patterns are located between
The edge of the substrate, which is formed with a gap and has a contact pattern
The portion is formed with a chamfered portion. Such a can
Self-sensing cantilever can be obtained by using a chiller unit.
Is easy and accurate mechanically and electrically for its holder
Can be mounted on the contact pattern
The cantilever unit is referenced by referring to the
To see if the unit is held in the correct position.
It becomes possible. (2) The cantilever unit holder of the present invention includes an elastic electrode positioned so as to be pressed against the contact pattern of the cantilever unit arranged at a regular position, and the cantilever unit is moved relative to the cantilever unit holder. The elastic electrode was held by the pressure contact force. According to such a cantilever unit holder, a cantilever unit having a self-detecting cantilever can be easily and accurately mounted mechanically and electrically. (3) The scanning probe microscope of the present invention scans the self-detecting cantilever of the cantilever unit held by the cantilever unit holder on the sample surface while maintaining the gap between the sample surface and the probe at a predetermined value. According to such a scanning probe microscope, the self-detecting cantilever as a scanning probe can be easily and accurately attached to and detached from the holder while maintaining good mechanical and electrical connections.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings. FIG. 1 is a diagram showing a configuration of a main part of a scanning probe microscope according to an embodiment of the present invention. A first permanent magnet 2 is mounted on an upper portion of the housing 1,
Is formed at the center portion thereof with a mandrel 3 surrounded by an annular groove 5. A cap-shaped mover 4 is loosely fitted to the mandrel 3 of the permanent magnet 2, and a voice coil 6 is wound around the outer periphery of the mover 4. The permanent magnet 2, the mandrel 3, the mover 4, and the voice coil 6 form a voice coil motor used for an acoustic speaker or the like.

At the center of the closed end 4a of the mover 4,
One end of a spindle 8 extending in the z direction is fixed.
A free end of a cantilever 14 having a fixed end supported by the middle cylinder 13 is fixed to the other end of the spindle 8. A cantilever unit holder 50, which will be described later in detail with reference to FIGS. 3 to 5, is fixed to the cantilever 14.
0 holds a cantilever unit 10 equipped with a self-detecting cantilever, which will be described later in detail with reference to FIGS.

A second permanent magnet 21 is mounted on the side surface of the housing 1, and a mandrel 22 surrounded by an annular groove 28 is formed at the center of the permanent magnet 21. A cap-shaped mover 23 is loosely fitted to the mandrel 22, and the mover 2
A voice coil 25 is wound around the outer periphery of the voice coil 3. The second permanent magnet 21, the mandrel 22, the mover 23, and the voice coil 25 form a voice coil motor similar to that described above.

One end of a spindle 27 in the x direction is fixed to the mover 23, and the other end of the spindle 27 is fixed to the side of the middle cylinder 13. Although this voice coil motor acts on the spindle 27 in the main scanning direction (X direction), a voice coil motor of the same configuration (not shown) is provided at a position rotated by 90 °, and is provided in the sub scanning direction (Y direction). Acts on the spindle. By driving the voice coil motors in the main and sub-scanning directions, the probe 10a provided at the free end of the cantilever unit 10 is raster-scanned on the sample surface. A sample table 31 is provided at a position facing the probe 10a, and a sample 32 to be observed is placed on the sample table 31. The sample stage 31 is set on a sample stage 33.

FIG. 2 is a block diagram of a drive circuit system connected to the scanning probe microscope of FIG. 1, and the same reference numerals as those in FIG. 1 represent the same or equivalent parts. When the displacement of the probe 10 a, for example, the amount of deflection of the probe 10 is detected by the displacement detector 49, the detection signal is compared with the reference value output from the reference value generator 42 by the differential amplifier 41. Since the reference value is equal to the value output from the displacement detector 49 when the distance between the probe 10a and the sample surface becomes a predetermined value,
When the distance between the probe 10a and the sample surface deviates from a predetermined value, the differential amplifier 41 outputs a signal having a magnitude corresponding to the deviation amount.

The differential signal output from the differential amplifier 41 is processed by an integrating circuit 43 and a proportional circuit 44,
It is input to the I converter 45. The VI converter 45 converts the input voltage signal into a current signal Iz and supplies the current signal Iz to the voice coil 6. That is, the displacement detector 49, the differential amplifier 41, the integrating circuit 43, the proportional circuit 44, and the VI converter 45 constitute a feedback circuit.

On the other hand, the raster scanner 46 supplies the scanning signal currents Ix and Iy in the main and sub scanning directions to the voice coils 25 and 35 wound around the X-direction mover 23 and the Y-direction mover 34, respectively. The raster scanner 46 supplies X and Y scanning signals to the CRT 47. Inspection information such as the shape and physical quantity of the sample surface is taken out from the input side of the VI converter 45 and supplied to the CRT 47.

FIG. 3 is a side view of the cantilever unit holder 50 according to one embodiment of the present invention, FIG. 4 is a diagram of arrow A in FIG. 3, and FIG. 5 is a diagram of arrow B in FIG. In this embodiment, the cantilever unit holder 50 is fixed to the cantilever 14 via a piezoelectric element plate 58.
The piezoelectric element plate 58 is provided for the purpose of resonating the cantilever when observing a soft sample such as a biomolecule.

On one side surface of the holder 50, four grooves 55 into which U-shaped portions of the S-shaped elastic electrodes 54 (54a to 54d) are respectively inserted are formed. A comb-shaped electrode guide 53 is cantilevered below the holder 50 so as to face the main body with a predetermined gap therebetween. The comb teeth of the electrode guide 53 are configured such that the positions corresponding to the grooves 55 are missing.

As shown in the drawing, each elastic electrode 54 has one U-shaped portion inserted into each groove 55, and the bent portion 57 of the portion extending from the other U-shaped portion to the end has an electrode guide. The protrusions 53 elastically protrude into the gap from between the 53 comb teeth. A prism 59 is fixed to the other side surface of the holder 50, and a cantilever base 52 is formed below the prism 59. Next, a cantilever unit according to an embodiment of the present invention will be described. FIG. 6 is a plan view of a cantilever unit 10 equipped with a self-detecting cantilever, and FIG. 7 is a side view of FIG. Chamfer 8 at the end of substrate 80
4 are provided. By providing the chamfer 84, the board can be smoothly inserted. Further, since the bent portion 57 is not damaged, the reliability is improved.

As shown in FIG. 7, the cantilever unit 10 according to the present invention is formed by laminating a thick silicon substrate 72 and a thin silicon substrate 71 to form a thin silicon substrate 7.
1. A self-detecting cantilever 70 having a probe 10a formed at a free end of a cantilever 71a protruding from one end of the cantilever 70, and at least the cantilever 71a of the cantilever 70 has an end as shown in FIG. And a glass epoxy substrate 80 that holds the cantilever 70 so as to protrude from the substrate.

On the main surface of the silicon substrate 71 on which the probe 10a is formed, a detection circuit (not shown) for outputting an electric signal in response to the amount of bending of the beam portion 71a, and a power supply line for the detection circuit and A bonding pad 72 for a signal line is formed. A plurality of wiring patterns 82 are formed on the surface of the glass epoxy substrate 80, and one end of each wiring pattern 82 has a contact pattern 82 a against which the bent portion 57 of each electrode 54 of the cantilever unit holder 50 is pressed. The bonding pad 82b is formed at the other end.

Bonding pad 7 of silicon substrate 71
2 and bonding pad 82 of glass epoxy substrate 80
b and the bonding wire 83 and the bonding pads 72 and 82b.
Is provided with a resin mold 81. When mounting such a cantilever unit 10 on the holder 50,
The operator holds the cantilever unit 10 in a horizontal state using tweezers or an appropriate dedicated jig, and holds the cantilever base 52 and the electrode guide 5 as shown in FIG.
3 and is inserted obliquely upward from below. Side view of cantilever base 52 and cantilever unit 1
Positioning marks 52a and 80a that match when the cantilever unit 10 is inserted into the holder 50 to a proper position are formed on the side surface of the glass epoxy substrate 80 of No. 0, respectively. As shown in FIG. 9, the operator can use the mark 52 a of the inserted cantilever unit 10.
Is matched with the mark 80a on the holder 50 side, it is determined that the cantilever unit 10 has been inserted into the holder 50 to the proper position.

Since the cantilever unit 10 is inserted against the elastic force of the electrode 54 elastically projecting into the gap, after being inserted into the gap, the cantilever unit 10 is pressed against the cantilever base 52 by the elastic force. , The electrode 54 and the cantilever base 52. Each electrode 5
4 is positioned in advance so that the bent portion 57 comes into contact with each contact pattern 82a of the glass epoxy substrate 80 when the cantilever unit 10 is inserted to a regular position. Therefore, each of the positioning marks 5
Cantilever unit 1 so that 2a and 80a match
As long as 0 is inserted into the holder 50, the cantilever unit 10 can be easily and accurately mounted mechanically and electrically.

Further, in the present embodiment, as shown in FIG. 6, since the contact pattern 82a is formed at a predetermined distance d3 from the tip of the glass epoxy substrate 80 in the insertion direction, the cantilever unit 10 is formed. If the insertion is not complete, the contact pattern 82a does not reach the bent portion 57 of the electrode 54. As a result, the detection signal becomes abnormal because no electrical contact is obtained, so that the cantilever unit 1 can be referred to by referring to the detection signal.
This makes it possible to recognize whether or not 0 is held at a regular position.

Next, a method for positioning the probe 10a at a desired position on the sample surface using the prism 59 will be described with reference to FIGS. As shown in FIG. 12, the prism 59 is fixed so that its mirror surface 59a is inclined with respect to the sample surface, and the virtual optical axis L1 passing through the probe 10a perpendicularly from the sample surface is bent obliquely upward. Becomes the virtual optical axis L2. Therefore, as shown in FIG. 10, the optical axis 91a of the optical microscope 90 and the virtual optical axis L
2 and the optical microscope 90, FIG.
As shown in (1), an image of the sample surface looking down from directly above the probe 10a can be observed, and the positioning of the probe 10a on the sample surface becomes extremely easy.

The optical microscope 90 is moved downward as shown by the broken line in FIG.
, And as shown in FIG. 11 (b),
The positional relationship between the probe 10a and the sample surface in the vertical direction can be observed. In the present embodiment, FIG.
Since the width d1 of the cantilever unit holder 50 and the width d2 of the cantilever unit 10 are substantially equal to each other, if the cantilever unit 10 is inserted so that both end faces are aligned, positioning in the width direction is also achieved at the same time. .

[0027]

According to the present invention, the following effects are achieved. (1) Since the cantilever unit is sandwiched by the elastic electrodes that are in pressure contact with the electrode pattern of the cantilever unit to obtain electrical contact, the self-detecting cantilever can be easily and accurately mounted both mechanically and electrically. Become like (2) A prism is provided on the cantilever unit holder, and the optical axis passing through the probe perpendicularly from the sample surface is refracted and taken out, so if this optical axis is aligned with the optical microscope and the optical axis, An image looking down on the sample surface can be observed from directly above the needle, and the positioning of the probe on the sample surface becomes extremely easy. (3) Since a mark is provided on both the cantilever unit and the holder when the cantilever unit is inserted to the proper position, it is easy to visually recognize that the cantilever unit has been inserted to the proper position. (4) The contact pattern of the cantilever unit is provided away from the end so that the electrode on the holder does not come into contact with the contact pattern unless the cantilever unit is inserted to the correct position. Then, it can be easily recognized whether or not the cantilever unit has been inserted to the proper position. (5) Since a self-sensing cantilever is used as a scanning probe for a scanning probe microscope and is held by the cantilever unit holder, the cantilever as a scanning probe is mechanically and electrically connected to the holder. Can be easily and accurately mounted.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a main part of a scanning probe microscope provided with a cantilever unit holder of the present invention.

FIG. 2 is a block diagram of a drive circuit system of the scanning probe microscope of FIG.

FIG. 3 is a side view of the cantilever unit holder of the present invention.

FIG. 4 is a view taken in the direction of arrow A in FIG. 3;

FIG. 5 is a view taken in the direction of the arrow B in FIG. 3;

FIG. 6 is a plan view of a cantilever unit of the present invention equipped with a self-sensing cantilever.

FIG. 7 is a side view of the cantilever unit of FIG. 6;

FIG. 8 is a diagram showing a method of mounting a cantilever to a holder.

FIG. 9 is a side view of the holder on which the cantilever unit is mounted.

FIG. 10 is a diagram showing a method of observing the position of a probe using an optical microscope.

FIG. 11 is a diagram showing an image observed by an optical microscope.

FIG. 12 is a diagram for explaining a function of a prism provided on a holder.

FIG. 13 is a diagram schematically showing a configuration of a conventional scanning probe microscope.

[Explanation of symbols]

 Reference Signs List 10 cantilever unit 10a probe 50 cantilever unit holder 52 cantilever base 52a, 80a positioning mark 53 electrode guide 54 elastic electrode 59 prism 70 self-detecting cantilever 80 glass epoxy substrate

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-5-248810 (JP, A) JP-A-7-325092 (JP, A) JP-A-9-243648 (JP, A) JP-A-10- 332716 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) G01N 13/10-13/24 JICST file (JOIS)

Claims (6)

(57) [Claims] A self-detecting cantilever 1. A having a detection portion for detecting the amount of deflection of the cantilever portion and the cantilever portion the probe is formed at the free end of the cantilever beam, the self-detecting cantilever, no less a substrate for holding so as to protrude from the free end is an end of the cantilever portion also is formed on the surface of the substrate, comprising the said detecting portion and electrically connected to the plurality of contact patterns, the plurality of Contact pattern is a predetermined distance from the edge of the board
The edge of the substrate, which is formed with a gap and has a contact pattern
A cantilever unit having a chamfered portion in a portion . 2. The cantilever unit according to claim 1,
A cantilever unit holder for holding the Tsu bets, contours of cantilever units arranged in a normal position
Elastic body positioned so as to be pressed against the object pattern
An electrode, and the cantilever unit includes a cantilever.
The pressure of the elastic electrode against the bar unit holder
Accordingly, the cantilever unit holder is held. 3. The cantilever unit holder according to claim 1, wherein
So that it is arranged facing one main surface with a predetermined gap.
The end is cantilevered to the cantilever unit holder.
And a resilient electrode is provided in a gap from a comb portion of the electrode guide.
Elastically protrude from the cantilever unit
Press the cantilever unit holder against one main surface in the gap
Cantilever unit holder according to claim 2, characterized in that that. 4. An end face of the cantilever unit has a
A mark is formed on the cantilever unit;
The holder has a cantilever unit held in the correct position.
A second landmark is formed at a position of the unit opposite the first landmark.
Cantilever unit holder according to claim 2 or 3, characterized in that made the. 5. A cantilever in a regular position.
The free end crosses the free end of the knit cantilever
A virtual optical axis along the the displacement direction, the optical to the virtual optical axis
The cantilever unit holder according to any one of claims 2 to 4, further comprising a light refraction member for refracting light . 6. The method according to claim 2, wherein
Equipped with a cantilever unit holder
Of the cantilever unit held by the bar unit holder
Use a self-detecting cantilever to increase the gap between the sample surface and the probe.
A scanning probe microscope that scans a sample surface while maintaining a predetermined value .