JPH1026569A - Measuring apparatus for sticking force - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a measuring apparatus by which the sticking force of a very small body can be measured with high accuracy and with a simple configuration by a method wherein a wedge-shaped probe having a contact face capable of coming into contact with the very small body is installed at the tip of a cantilever. SOLUTION: A contact face 16a at a wedge-shaped probe 16 installed at the tip (free end) of a beam part 12 extended to the long-axis direction of a cantilever 10 is formed to be a shape expanded to the long-axis direction. When the contact face 16a is brought into contact with a very small body 18 on a board 20, the very small body 18 is not pressed to the board 20, and only a force which is moved rectlinearly with the face 16a acts while the very small body is hardly turned. By this constitution, when the contact face 16a is brought close to the very small body 18, the displacement of the beam part 12 which is displaced according to a force acting on the probe 16 is measured by a displacement sensor 30, and the displacement of a leaf spring 24 which is elastically deformed according to a force acting on the cantilever 10 is measured by a displacement sensor 32. Then, displacement data is computed and processed by an external processor, and the sticking force of the very small body 18 which is stuck to the board 20 is measured.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an adhesive force measuring apparatus for measuring an adhesive force of a measurement object, for example, a cell or a minute sample such as a biological sample attached to a substrate.

[0002]

2. Description of the Related Art Conventionally, as disclosed in, for example, Japanese Patent Application Laid-Open No. 6-213655, when a probe having a sharpened tip scans an object to be measured, the force applied to the probe is measured. There has been known a measuring device capable of measuring various kinds of information on a measurement object by detecting the information.

In recent years, attempts have been made to measure, for example, the adhesion of an object to be measured attached to a substrate, in particular, a minute object such as a cell or a biological sample, by applying the above-described measurement technique. I have.

[0004]

However, it is known that the following problems occur when the adhesion of a minute object is measured using a probe having a sharpened tip.
Specifically, as shown in FIGS. 5A and 5B, the probe 4 provided on the cantilever 2 is applied to the micro body 6 in a state where a pressing force in the direction of arrow F in the drawing is applied. When attached, it is ideal that a force along the F direction acts on the minute body 6.

However, the ridge line (or side peripheral surface) 4a of the probe 4
Has a predetermined inclination angle, so that when the probe 4 is applied to the minute body 6, a force F ′ in the direction perpendicular to the ridge line 4 a is applied to the minute body 6 at the abutting point S. Will work. In this case, the minute body 6 has a component force F1 along the arrow F direction in the figure and a component force F2 in a direction orthogonal to the component force F1.
(That is, the force pressing the minute body 6 against the substrate 8) acts (see FIG. 5A). As a result, the minute body 6
In this case, since the component force F2 acts in addition to the actual adhesive force, the measurement accuracy of the adhesive force of the minute body 6 is significantly reduced.

Further, when the probe 4 is applied to a position deviated from the center axis A of the minute body 6, the minute body 6
Is rotated in the direction of the arrow M in the figure with respect to the center axis A by the moment of the force acting on (see FIG. 5B).
When such a rotational force acts, the measurement accuracy of the adhesive force of the minute body 6 is significantly reduced as described above.

The present invention has been made in order to solve such a problem, and an object of the present invention is to provide an adhesive force measuring device capable of measuring the adhesive force of a minute body with a simple configuration with high accuracy. To provide.

[0008]

In order to achieve the above object, an adhesive force measuring apparatus according to the present invention is provided with a cantilever and a tip provided at the end of the cantilever and capable of abutting on a minute body. A wedge-shaped stylus having an abutment surface, supporting the cantilever, and responding to a force acting on the cantilever when the minute body is applied to the abutment surface of the stylus. And a support mechanism that is elastically deformable.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an adhesive force measuring device according to a first embodiment of the present invention will be described with reference to FIGS. As shown in FIGS. 1A, 1B, and 1C, the adhesive force measuring device according to the present embodiment includes a cantilever 10
And a micro body 18 provided at the tip of the cantilever 10
The wedge-shaped stylus 16 having an abutment surface 16a capable of abutment with the stylus 16 and the cantilever 10 are supported. And a support mechanism that is elastically deformable in response to a force acting on the beam 10.

The cantilever 10 has a beam portion 12 extending in the longitudinal axis direction of the cantilever 10, a support portion 14 for supporting the base end of the beam portion 12, and a substrate 20 with a predetermined adhesive force. The contact surface 16a that can be attached to the attached minute body 18 (FIG. 1)
(See (b)) and a wedge-shaped stylus 16 provided at the tip (free end) of the beam portion 12.

The contact surface 16 a is formed so as to extend in a direction perpendicular to the longitudinal axis of the cantilever 10. When the contact surface 16 a contacts the minute body 18, the minute body 18 is attached to the substrate 20. It is configured such that only the force for translating the minute body 18 acts without being pressed and the minute body 18 hardly rotates.

The supporting mechanism has one leaf spring 24 whose base end is elastically deformed and supported by a holding portion 22 provided on a main body (not shown) of the adhesive force measuring device, and is provided at the tip of this leaf spring 24. And supporting means for supporting the supporting portion 14 of the cantilever 10.

The support means includes a support portion 14 of the cantilever 10.
Are provided, and a pressing member 28 for fixing the intermediate fixing member 26 to the tip of the leaf spring 24 is provided.

The adhesive force measuring device according to the present embodiment has a first displacement sensor 30 capable of optically measuring the displacement of the beam portion 12 of the cantilever 10 and an optical sensor for measuring the displacement of the leaf spring 24. And a second displacement sensor 32 that can be measured.

In the present embodiment, the minute body 18
Corresponds to, for example, a cell or a biological sample attached to the substrate 20, and in the following description, these are collectively simply referred to as a micro body 18.

According to such a configuration, when the minute body 18 is applied to the contact surface 16a of the stylus 16, the displacement of the beam portion 12 which is displaced in accordance with the force acting on the stylus 16 is changed to the first position. The leaf spring 24 is optically measured by the displacement sensor 30 and elastically deforms at the same time according to the force acting on the cantilever 10.
Is optically measured by the second displacement sensor 32. At this time, the displacement data output from the first and second displacement sensors 30 and 32 are subjected to predetermined arithmetic processing by an external processing device (not shown). Then, based on the calculation result, the minute body 18 attached to the substrate 20
Will be measured.

Next, the cantilever 1 applied to the present embodiment.
0 will be described with reference to FIGS. As shown in FIG. 2D, the cantilever 10 manufactured by this manufacturing method has a length L of the beam portion 12 extending from the support portion 14 of about several μm to several mm. The thickness T of the portion 12 is about 0.5 μm to several tens μm, the height H of the stylus 16 is about 1 μm to several tens μm,
The width W of a (see FIG. 1B) is about 0.5 μm to several tens μm.

First, as shown in FIG. 2A, a silicon wafer having an active layer 34 made of silicon having a <100> plane orientation bonded to a silicon substrate 38 via a silicon oxide layer (insulating layer) 36 is prepared. I do. After forming the silicon nitride film 40 on the front and back surfaces of the silicon wafer, photolithography is performed to pattern the silicon nitride film 40 formed on the front surface into a predetermined shape. Thereafter, the active layer 34 that is exposed is subjected to dry etching, whereby the active layer 34 is dug down vertically to a silicon oxide layer (insulating layer) 36 (step 1).

Subsequently, as shown in FIGS. 2A and 2B, the active layer 34 exposed by the dry etching is subjected to a thermal oxidation treatment in a diffusion furnace (not shown).
A sidewall 42 made of silicon oxide is formed (Step 2).

At this time, the active layer 34 of the silicon wafer is subjected to <1
A trapezoidal portion 44 extending in the <10> direction is formed (see FIG. 2B).

Next, as shown in FIG. 2C, an oxide film protection layer (not shown) is formed on the back surface of the silicon wafer so that the back surface of the silicon wafer is not etched by dry etching described later. Then, after removing the silicon nitride film 40 on the front side by dry etching, wet anisotropic etching is performed on the active layer 34 using a KOH aqueous solution (36%) (step 3).

As a result, a portion corresponding to the wedge-shaped stylus 16 (see FIG. 1) is formed by exposing the (111) surface 46 made of silicon at the tip of the trapezoidal portion 44. In the manufacturing process of Step 3, the active layer 34 has the thickness of the beam portion 12 of the cantilever 10 described above.
The wet anisotropic etching is performed so as to have a thickness T (see FIG. 2D).

Subsequently, as shown in FIG. 2D, after an oxide film protection layer (not shown) is formed on the surface of the active layer 34, the oxide film protection layer formed on the back side of the silicon wafer is removed. Remove. Then, wet anisotropic etching is performed on the silicon substrate 38 from the back side of the silicon wafer using an aqueous KOH solution (36%) (step 4).

In the manufacturing process of step 4, the silicon nitride film 40 formed on the back side of the silicon wafer functions as a mask for wet anisotropic etching.

Finally, the oxide film protection layer formed on the surface of the active layer 34 and the silicon oxide film (insulating layer) 36 remaining on the beam portion 12 having the length L are etched and cantilevered. Support portion 14 of beam 10 (FIGS. 1A and 1B)
The silicon substrate 38 is etched so as to have the shape (step 5).

As a result, the cantilever 10 applied to the present embodiment is manufactured. In addition, following step 5, the surface of the beam portion 12 on the opposite side to the surface on which the stylus 16 is formed so as to smoothly reflect the displacement measurement light from the first displacement sensor 30. Then, for example, a metal may be coated.

As described above, according to the present embodiment, the abutment surface 16 that extends in the direction orthogonal to the longitudinal axis of the cantilever 10.
a, when the contact surface 16a is applied to the minute body 18 at the time of measuring the adhesive force, the minute body 18 is almost not rotated against the substrate 20 and almost rotates. Thus, it is possible to efficiently generate only the force for translating the minute body 18. As a result, it is possible to provide an adhesive force measuring device capable of measuring the adhesive force of the minute body 18 with high accuracy.

The cantilever 1 applied to this embodiment
0 can be manufactured using a semiconductor manufacturing process, so that a large number of styluses 16 having high reproducibility of shape can be manufactured at low cost. Further, by forming the stylus 16 at the tip (free end) of the beam portion 12 of the cantilever 10, the stylus 16 and the minute body 18 can be formed using, for example, an optical microscope.
When performing the positioning between, the positioning can be performed extremely easily and accurately.

Next, an adhesive force measuring apparatus according to a second embodiment of the present invention will be described with reference to FIG. In the description of the present embodiment, the same components as those of the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

As shown in FIG. 3A, the adhesive force measuring device according to the present embodiment includes a cantilever 48 and this cantilever 48.
And a support mechanism formed integrally with the support member and elastically deformable in response to a force acting on the cantilever 48.

The cantilever 48 has a wedge-shaped shape provided at the tip (free end) of the beam portion 50 and having an abutting surface 52a capable of abutting against the minute body 18 (see FIG. 1A). A stylus 52 is formed.

The contact surface 52a is formed so as to extend in a direction perpendicular to the longitudinal axis of the cantilever 48. When the contact surface 52a is applied to the minute body 18, the minute body 18 1 (a)), and only the force for translating the minute body 18 is exerted without being pressed against the minute body 18 and hardly rotating.

The support mechanism is arranged so that when the minute body 18 is applied to the contact surface 52 a of the stylus 52, the longitudinal axis of the cantilever 48 is elastically deformed in accordance with the force acting on the cantilever 48. Pair of spring means 5 arranged perpendicular to and parallel to each other
4 and a supporting portion 56 formed integrally with the pair of spring means 54 and supporting the pair of spring means 54 so as to be elastically deformable.

A pair of spring means 5 applied to this embodiment
4 is, for example, a pair of leaf springs 54 arranged in parallel with each other.
To form a parallel spring structure. In addition, the support portion 56 of the support mechanism is provided with an adhesive force measuring device main body (not shown).
Is configured to be able to be adhered to the fixing surface 58a of the holder 58 provided in the first embodiment.

In such a configuration, only by bonding the support portion 56 of the support mechanism to the fixing surface 58a of the holder 58,
When the contact surface 52a is applied to the minute body 18 at the time of measuring the adhesive force, only the force for translating the minute body 18 without the minute body 18 being pressed against the substrate 20 and the minute body 18 hardly rotating. To work, the cantilever 48 can be positioned in place.

According to such a configuration, when the minute body 18 is applied to the contact surface 52a of the stylus 52, the displacement of the beam portion 50 which is displaced according to the force acting on the stylus 52 is changed to the first position. The displacement of a pair of leaf springs 54 elastically deformed in response to the force acting on the cantilever 48 is measured optically by the second displacement sensor 32. Then, similarly to the first embodiment, the first
Based on the displacement data output from the second displacement sensors 30 and 32, the adhesive force of the minute body 18 attached to the substrate 20 is measured.

Next, the cantilever 4 applied to this embodiment will be described.
8 and the method of manufacturing the support mechanism are shown in FIGS.
This will be described with reference to FIG. Note that this manufacturing method can use a semiconductor manufacturing process as in the first embodiment, and the beam portion 50 and the stylus 52 of the cantilever 48 manufactured by this manufacturing method can be used. Each dimension of the surface 52a can be the same dimension as in the first embodiment.

First, as shown in FIG. 3B, a silicon wafer having an active layer 60 made of silicon bonded to a silicon substrate 64 via a silicon oxide layer (insulating layer) 62 is prepared. After the silicon nitride film 66 is formed on the front and back surfaces of the silicon wafer, photolithography is performed to pattern the silicon nitride film 66 formed on the front surface into a predetermined shape (step 1).

Thereafter, as shown in FIG. 3C, the exposed active layer 60 is subjected to dry etching, so that the active layer 60 is converted to a silicon oxide layer (insulating layer).
Drill vertically down to 62 (step 2).

At the time when the manufacturing process of Steps 1 and 2 is completed, portions corresponding to the beam portion 50, the stylus 52, and the pair of leaf springs 54 are formed. FIG. 3 (c)
FIG. 4 is a cross-sectional view of a portion taken along line cc in FIG.

Subsequently, in a diffusion furnace (not shown), the active layer 60 exposed by the dry etching is subjected to a thermal oxidation treatment, so that a silicon oxide sidewall 68 is formed.
(See FIG. 3C) is formed (step 3).

Next, as shown in FIG. 3D, the silicon nitride film 66 remaining on the active layer 60 is removed in the same manner as in the manufacturing process of the first embodiment. The support portion 56 of the support mechanism is formed by performing wet anisotropic etching on the silicon substrate 64 from the back side (step 4).

As a result, the cantilever 48 and the support mechanism applied to the present embodiment are integrally manufactured.
According to the present embodiment, in addition to the effect of the first embodiment, by adopting a parallel spring structure having a pair of leaf springs 54 as a support mechanism, the force acting on the cantilever 48 is reduced. Accordingly, the pair of leaf springs 54 always move in parallel. As a result, it is possible to reduce the measurement error caused by the warpage of each leaf spring 54,
The adhesive force can be measured with higher measurement accuracy.

Further, since the support mechanism applied to the present embodiment can be integrally formed by using a semiconductor manufacturing process, it is possible to easily make the parallel spring structure compact. As a result, the resonance frequency of the pair of leaf springs 54 can be increased, so that a structure that is not easily affected by disturbance vibration noise can be realized. For this reason, it is possible to measure the adhesive force with a high S / N ratio.

Further, since a smaller parallel spring structure can be formed by the semiconductor manufacturing process, it is possible to realize a compact apparatus. next,
An adhesive force measuring device according to a third embodiment of the present invention will be described with reference to FIG. In the description of the present embodiment, the same components as those of the second embodiment are denoted by the same reference numerals, and description thereof will be omitted.

As shown in FIG. 4, the supporting mechanism applied to the present embodiment has a small body 1 on the contact surface 52a of the stylus 52.
8 (see FIG. 1 (a)), the cantilever 48
Is integrally formed with a displacement detection element capable of detecting the displacement of the pair of leaf springs 54 generated in response to the force acting on the pair of leaf springs 54. Further, in the present embodiment, the pair of leaf springs 54 are made conductive by a doping process described later. In addition,
The other configuration is the same as that of the second embodiment, and the description is omitted.

The displacement detecting element has a counter electrode 70 integrated in parallel with the pair of leaf springs 54 and a counter electrode when the pair of leaf springs 54 is displaced according to the force acting on the cantilever 48 during the measurement of the adhesive force. A detection circuit capable of detecting a change in capacitance between the electrode 70 and the leaf spring 54 is provided.

Here, if the leaf spring 54 of the pair of leaf springs 54 facing the opposing electrode 70 is temporarily indicated by reference numeral 54a, the detection circuit detects the capacitance between the leaf spring 54a and the opposing electrode 70. Is configured to be able to detect a change in

In such a detection circuit, the first electrode 72 integrated from the support portion 56 of the support mechanism to the counter electrode 70 and the second electrode 72 integrated from the support portion 56 to the parallel spring structure are provided. And the first and second electrodes 74 are provided.
The signals output through the electrodes 72 and 74 are supplied to an external processing device (not shown) via the first and second wirings 76 and 78.

In such a configuration, when the minute body 18 is applied to the contact surface 52a of the stylus 52, the cantilever 4
The displacement of the parallel spring structure which is elastically deformed in response to the force acting on the capacitance 8 is detected by the detection circuit as a change in the capacitance, and the detection signal is transmitted to the outside via the first and second wirings 76 and 78. It is supplied to the processing device. On the other hand, when the minute body 18 is applied to the contact surface 52a of the stylus 52,
The displacement of the beam portion 50 that is displaced in accordance with the force acting on
Is optically measured by a displacement sensor 30 (see FIG. 1A), and the displacement data is supplied to an external processing device. Then, in the external processing device, predetermined processing is performed on the detection signal and the displacement data, and based on the calculation result, the attachment of the minute body 18 attached to the substrate 20 (see FIG. 1A) is performed. The adhesion will be measured.

Next, the cantilever 4 applied to the present embodiment
8 and a method of manufacturing the support mechanism will be briefly described. Note that the manufacturing method of this embodiment is basically the same process as steps 1 to 4 of the second embodiment, and therefore, only the differences will be described in the following description.

First, in step 1 (see FIG. 3B), the active layer 60 of the bonded silicon wafer is made conductive by doping. Then, when the silicon nitride film 66 is patterned into a predetermined shape, a pattern corresponding to the counter electrode 70 is formed at the same time.

Next, in step 2 (see FIG. 3C), a portion corresponding to the beam portion 50, the stylus 52, and the pair of leaf springs 54 is formed, and at the same time, a portion corresponding to the counter electrode 70 is formed. .

Then, after the fabrication process of steps 3 and 4 (see FIG. 3D), the first and second electrodes 7
2, 74 are formed. As a result, the cantilever 48 and the support mechanism applied to the present embodiment are integrally manufactured.

According to the present embodiment, in addition to the effects of the first and second embodiments, the displacement detecting element of the parallel spring structure is integrated in the support mechanism, so that the adhesive force measuring device can be used in the second embodiment. The second displacement sensor 32 (see FIG. 1A) can be eliminated. As a result, it is possible to reduce the size of the adhesive force measuring device.

When the displacement detecting means (specifically, the second displacement sensor 32) for detecting the displacement of the parallel spring structure is separately provided, the size of the parallel spring structure depends on the size of the displacement detecting means. Dimensions (specifically, a pair of leaf springs 54
Is determined, it is difficult to shorten the length of the pair of leaf springs 54 to a certain value or less. On the other hand, in this embodiment, since the displacement detection element having the same size as the parallel spring structure can be integrally formed by the semiconductor manufacturing process, the dimensions of the parallel spring structure (specifically, The length of the pair of leaf springs 54) can be shortened with high accuracy and easily. As a result, the resonance frequency of the pair of leaf springs 54 can be increased, so that a structure that is not easily affected by disturbance vibration noise can be realized.

In this embodiment, a displacement detecting element of a type for detecting a change in capacitance is applied, but the present invention is not limited to this. For example, a piezoelectric layer or a strain resistance layer is integrally formed on a pair of leaf springs 54 as a displacement detecting element, and by detecting a current change due to a resistance change when the parallel spring structure is displaced, the attachment of the minute body 18 is performed. The contact force may be measured. When this modification is applied, the counter electrode 70 becomes unnecessary.

[0058]

According to the present invention, the provision of a wedge-shaped stylus having an abutting surface capable of abutting on a minute body makes it possible to measure the adhesion of the minute body with high accuracy. An adhesive force measuring device can be provided.

[Brief description of the drawings]

1A is a diagram showing a configuration of an adhesive force measuring device according to a first embodiment of the present invention, FIG. 1B is a perspective view showing a configuration of a cantilever, and FIG. The perspective view which expands and shows the part of the stylus provided in the front-end | tip of a beam part.

2 (a) to 2 (d) are views showing a process for manufacturing the cantilever shown in FIG. 1;

3A is a diagram showing a configuration of an adhesive force measuring device according to a second embodiment of the present invention, and FIGS. 3B to 3D are cantilevers shown in FIG. The figure which shows the manufacturing process of a beam and a support mechanism.

FIG. 4 is a diagram showing a configuration of an adhesive force measuring device according to a third embodiment of the present invention.

5A and 5B are diagrams showing a state in which an adhesive force is measured using a conventional apparatus, and FIG. 5A shows a state in which a force for pressing a minute body against a substrate acts in addition to the actual adhesive force. Diagram,
(B) is a diagram showing a state in which a moment of force is acting on the minute body.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Cantilever 12 Beam 14 Support 16 Contact stylus 16a Contact surface 18 Micro body 20 Substrate 22 Holder 24 Leaf spring

Claims (3)

[Claims] A wedge-shaped stylus provided at a tip of the cantilever and having an abutting surface capable of abutting on a minute body; supporting the cantilever; An adhesive force measuring device, comprising: a support mechanism that is elastically deformable according to a force acting on the cantilever when the minute body is applied to an abutting surface of a stylus. 2. The support mechanism according to claim 1, wherein the cantilever is elastically deformed in response to a force acting on the cantilever when the minute body is applied to the contact surface of the stylus. 2. The device according to claim 1, further comprising a pair of spring means arranged perpendicular to the longitudinal axis and parallel to each other, wherein the pair of spring means are formed integrally with the cantilever. Adhesive force measuring device. 3. The support mechanism detects a displacement of the pair of spring means caused by a force acting on the cantilever when the minute body is applied to an abutting surface of the stylus. 3. The adhesive force measuring device according to claim 2, wherein a possible displacement detecting element is formed integrally.