JP2001255221A - Contact sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an extremely thin contact sensor possible of being arranged in an extremely narrow space. SOLUTION: This contact sensor is characterized by having a projection part provided in a thin plate comprising a semiconductor, an opening part provided in the thin plate comprising the semiconductor in the circumferential part of the projection, and a strain sensor provided adjacent to the projection and detecting a force exerted on the projection by the strain of the thin plate comprising the semiconductor.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a contact sensor, and more particularly, to a thin-film high-sensitivity contact sensor suitable for an apparatus which functions at a very small distance from an object.

[0002]

2. Description of the Related Art In a device such as a high-magnification microscope objective lens which functions at a very small distance from an object, there is always a danger that the object and the device will come into contact with each other and damage either one. Exists.

In a high-magnification microscope objective lens, it is usually possible to avoid the danger of contact by installing an autofocus function. However, if focus detection fails due to the shape of the object, it is still necessary. Since there is a risk of breakage, it is desirable to mount a contact sensor and apply an interlock.

Although an optical distance measuring sensor may be used for such an application, accurate distance measurement may not be performed depending on the state of the object surface.
Mechanical contact sensors are most desirable.

[0005] As an example of such a contact sensor, there is, for example, a contact sensor which is hardly broken and is made small as disclosed in Japanese Patent Application Laid-Open No. 11-118636.

[0006]

Generally, such contact sensors are not provided between the object and the objective lens because the object and the object are not kept exactly parallel. Must be located.

However, the distance of the high-magnification objective lens to the object, that is, the work distance is 0.2 mm.
In the following cases, there is no contact sensor that can be arranged in such a narrow space.

The present invention has been made in view of the above problems, and has as its object to provide an extremely thin contact sensor that can be arranged in a very narrow space.

[0009]

According to the present invention, in order to solve the above-mentioned problems, (1) a protrusion provided on a thin plate made of a semiconductor and a thin plate made of the semiconductor around the protrusion are provided. A contact sensor is provided, comprising: a provided opening; and a strain sensor provided near the protrusion and detecting a force acting on the protrusion by distortion of a thin plate made of the semiconductor. .

(Corresponding Embodiment) The first and second embodiments described later correspond to this embodiment.

(Function) In the main body 2 made of a semiconductor thin plate, a notch (opening) 9 is formed around a plurality of projections 8 and a sensor section as a strain sensor is provided near the projections 8. When the projections 8 are in contact with the object and a stress is generated due to the arrangement of the elements 10, the sensor section 10 is distorted and the contact of the object is detected.

According to the present invention, in order to solve the above-mentioned problems, (2) the thin plate made of the semiconductor is thinner immediately under the protrusion than the peripheral portion. A contact sensor as described is provided.

(Corresponding Embodiment) The first embodiment described below corresponds to this.

(Operation) The thickness of the region 11 in which the projection 8 and the sensor element 10 as a strain sensor are formed is made smaller than the thickness of the main body 2 made of a semiconductor thin plate around it. Even if the mounting surface of the contact sensor is a simple flat surface, no special spacer is required,
The operation clearance of the projection 8 as the pressure receiving portion is secured.

According to the present invention, in order to solve the above-mentioned problems, (3) the opening is formed so as to surround the projection, and the area immediately below the projection by the opening forms a peripheral area. The contact sensor according to (1) or (2), wherein the contact sensor is supported as a cantilever from the thin plate made of the semiconductor.

(Corresponding Embodiment) The first embodiment described later corresponds to this.

(Operation) Since the region 11 in which the projection 8 as the pressure receiving portion is formed constitutes a cantilever whose one end is supported by the main body 2 made of a surrounding semiconductor thin plate, the pressure receiving portion is formed. Easily deformed by the stress applied to the projections 8 of the above.

[0018]

Embodiments of the present invention will be described below with reference to the drawings.

(First Embodiment) As a first embodiment of the present invention, a contact sensor used by being attached to the tip of a microscope objective lens will be described with reference to FIGS.

FIG. 1 shows the structure of a contact sensor according to a first embodiment of the present invention.

Here, FIG. 1A is a plan view of the contact sensor according to the first embodiment, and FIG.
It is AA 'sectional drawing in (a) of FIG.

That is, the contact sensor 1 according to the first embodiment of the present invention comprises an annular main body portion 2 made of a semiconductor thin plate such as an n-type single crystal silicon and a semiconductor thin plate such as an n-type single crystal silicon. And a flexible thin film portion 4 made of a semiconductor thin plate such as n-type single crystal silicon.

The ring-shaped main body 2 and the electrode 3 are composed of an n-type single-crystal silicon semiconductor thin plate, and are connected by a flexible thin film 4 formed integrally therewith. ing.

On the annular main body 2, eight sensor sections 5 are formed along the circumference, and on the electrode section 3, an electronic circuit 6 and a plurality of external lead electrodes 7 are formed. Have been.

The sensor portion 5 has a projection 8 as a pressure receiving portion formed in a dome shape having elasticity like a rubber member.
And a notch (opening) 9 surrounding three sides of the projection 8
And a sensor element 10 as a strain sensor which is disposed in the vicinity of the projection 8 as a pressure receiving portion and at a portion without a notch (opening) 9.

FIG. 2 is an enlarged view of the sensor section 5 of FIG.

That is, the sensor element 10 as a strain sensor in the sensor section 5 is formed in a rectangular shape by the p-type diffusion layer at the above-mentioned portion on the annular main body 2 made of a thin semiconductor plate such as n-type single crystal silicon. Four piezoresistive elements 10a, 10b, 1 formed to constitute each side
0c and 10d.

Further, as can be seen from FIG. 2, the projection 8 as a pressure receiving portion and the sensor element 1 disposed in proximity to the projection 8 are provided.
Immediately below the 0 region 11, the thickness (t1) of the semiconductor thin plate such as n-type single crystal silicon is formed so as to be smaller (t1 <t2) than the thickness (t2) of the semiconductor thin plate in the other regions. Have been.

As can be seen from FIG. 2, this region 1
Reference numeral 1 denotes a cantilever supported by a portion of the surrounding main body 2 where the notch (opening) 9 is not formed.

When a stress is applied vertically to the main surface of the main body 2 made of a semiconductor thin plate made of n-type single crystal silicon, the region 11 is pushed down with respect to the projection 8 as a pressure receiving portion. At this time, tensile stress acts on the surface of the portion where the piezoresistive elements 10a, 10b, 10c, and 10d are formed.

Here, the direction of the stress is the same as the current path of the piezoresistive elements 10a and 10b, and is orthogonal to the current paths of the piezoresistive elements 10b and 10d.

The current paths of the piezoresistive elements 10a and 10b are along the <110> crystal orientation.

FIG. 3 is an enlarged view of the sensor element 10 shown in FIG. 1 and FIG.

Here, FIG. 3 (a) shows the sensor element 10
FIG. 3B is a plan view of the portion, and FIG. 3B is a cross-sectional view taken along the line AA ′ in FIG.

That is, the four piezoresistive elements 10a, 10b, 10c, and 10d in the sensor element 10 are:
Each of the wiring layers 12 forms a bridge circuit.

In this case, as shown in the cross-sectional view of FIG. 3B, the wiring layer 12 is formed by a lower polyimide film 13 to form a main body made of a semiconductor thin plate of n-type single crystal silicon or the like. 2 and is electrically connected to a piezoresistive element 10b formed of a p-type diffusion layer by a contact hole 15 opened at a predetermined portion of the lower polyimide film 13.

This electrical connection is made similarly for the other piezoresistive elements 10a, 10c and 10d.

The upper part of the wiring layer 12 is covered with an upper polyimide film 14.

Although not particularly shown in FIGS. 1 and 2, the wiring of each of the sensor elements 10 of the eight sensor sections 10 is formed on the main body 2 made of a semiconductor thin plate such as n-type single crystal silicon. The wiring layer 12 formed between the lower polyimide film 13 and the upper polyimide film 14 is formed on the electrode portion 3 through the flexible thin film portion 4 shown in FIGS. Connected to the electronic circuit 6.

The electric circuit 6 is a CMOS-LSI, supplies power to the respective sensor elements 10, functions as a time division circuit for switching these in a time division manner, and amplifies the signals from the respective sensor elements 10. It has a function as a circuit.

The electronic circuit 6 is also connected to a plurality of electrodes 7, and is connected to an external controller by lead wires connected to the electrodes.

Next, a method of manufacturing the contact sensor 1 according to the present embodiment will be described with reference to FIGS. 4A to 4C and FIGS. 5A to 5C. .

First, as shown in FIG. 4A, a region 11 below the protrusion 8 as a pressure receiving portion on a low-concentration p-type semiconductor substrate 101 of silicon having a <100> plane orientation of the main surface.
A p-type diffusion layer 102 having a higher concentration than the substrate 101 is formed in a region corresponding to.

Thereafter, as shown in FIG. 4B, an n-type diffusion layer 103 is formed in a region to be the main body 2 and the electrode 3.

At this time, since the concentration of the p-type impurity is higher in the region where the p-type diffusion layer 102 is formed than in the other regions, the junction depth in this region becomes shallower.

Further, after this, the piezoresistive element 10
A relatively high concentration p-type diffusion layer 104 having a shallow junction depth of a, 10b, 10c, and 10d is formed.

Before and after this step, the electronic circuit 6 in the electrode section 3 is formed by a normal CMOS process.

Next, as shown in FIG. 4C, a silicon nitride film 105 is formed on the back surface of the semiconductor substrate 101 on the outer periphery of the region where the contact sensor 1 is formed.

An insulating film 106 made of a silicon oxide film is formed on the surface of a semiconductor substrate 101 made of silicon or the like, in which a wiring layer (not shown) of the electronic circuit 6 is formed in the same manner as a normal integrated circuit. Formed by technique.

On the surface side of the insulating film 106, a lower polyimide film 13, a wiring layer 12 made of an aluminum thin film, and an upper polyimide film 14 are sequentially formed.

At this time, the piezoresistive elements 10a, 10b, 10c,
10d and a contact hole (not shown) for electrically connecting to a wiring layer (not shown) of the electronic circuit 6 are formed;
Openings for a plurality of electrodes 7 serving as external lead electrodes are formed in predetermined regions of the upper polyimide film 14.

Thereafter, a protrusion 8 is formed in a predetermined region on the upper polyimide film 14 as a pressure receiving portion formed in a dome shape having elasticity.

The protruding portion 8 as a pressure receiving portion having this elasticity
Several methods are conceivable as a method of forming the resin.For example, a soft resin having a relatively low glass transition temperature is formed at a predetermined site by a method such as screen printing, and heated to form a dome shape. It can be formed by deforming and solidifying.

Next, as shown in FIG. 5A, a positive bias is applied to the n-type diffusion layer 103 to perform electrochemical etching in an alkaline solution.

At this time, the surface side of the semiconductor substrate 101 such as silicon is protected by mechanical sealing or the like, and the region of the n-type diffusion layer 103 is selected by using the pattern of the silicon nitride film 105 as a mask. As a result, a form as shown is obtained.

At this time, the insulating layer 106 made of a silicon oxide film functions as an etching stopper.

Here, the thickness of the region where silicon remains is defined by the junction depth of n-type diffusion layer 103 and the width of a depletion layer extending therefrom to a p-type substrate or p-type diffusion layer. The thickness can be strictly controlled to, for example, about 10 μm by applying an n-type impurity into the diffusion layer, applying a thermal diffusion process, and applying an electrochemical etching voltage.

The p-type diffusion layer 1 shown in FIG.
In the region where 02 is formed, as described above, the junction depth is smaller than the surrounding area and the concentration on the substrate side near the junction is high, so that the width of the depletion layer during electrochemical etching is suppressed. Therefore, the remaining silicon can be formed to be thinner than the surrounding thickness.

The difference between the thickness of the remaining silicon and the thickness of the surrounding silicon can also be strictly controlled by the p-type impurity introduction and thermal diffusion steps. As a result, a thin single-crystal silicon layer having high reproducibility is obtained. Can be obtained.

Next, as shown in FIG. 5 (b), the exposed region of the insulating film 106 made of a silicon oxide film is selectively removed by performing reactive ion etching from the back surface side. By removing the polyimide films 13 and 14 in that region and the silicon oxide film 106 on the surface of the semiconductor substrate 101 such as silicon by ablation, a notch (opening) 9 having a U-shape is formed.

The notch (opening) portion 9 is formed by not forming the n-type diffusion layer 103 in that region in advance so that silicon does not remain in this region during electrochemical etching. Is also possible.

In this method, the polyimide films 13 and 14
Will remain in the notched area, but since the rigidity of polyimide is sufficiently smaller than that of silicon, it does not significantly affect the characteristics of the sensor as described later.

It is also conceivable to apply a photolithography technique using reactive ion etching instead of the above-described excimer laser ablation.

Next, as shown in FIG. 5C, a region 107 corresponding to the hollow portion of the main body 2 in FIG.
Then, by cutting the polyimide films 13 and 14 on the outer periphery, the contact sensor 1 having the form shown in FIG. 1 can be obtained.

In this case, the thickness of the polyimide films 13 and 14 and the insulating film 106 can be easily reduced to a level of several μm by applying a semiconductor process.
In combination with the above-described method of forming a thin plate-like single-crystal silicon, it is possible to obtain an ultra-thin contact sensor 1 whose overall thickness is significantly less than 100 μm.

FIG. 6 shows a state in which the contact sensor 1 of the present embodiment is assembled to an objective lens 16 of a microscope.

That is, the lens frame front face 17 of the objective lens 16
, The main body 2 of the contact sensor 1 is adhered.

The electrode section 3 of the contact sensor 1 is formed by bending the flexible thin film section 4 existing between the main body section 2 and the electrode section 3 of the contact sensor 1 so that the objective lens 16 is bent. Is attached to the side of the lens frame.

Although not shown, a lead wire for connecting to an external controller is connected to the external lead electrode 7 of the electrode section 3.

The flexible thin film portion 4 is composed of the lower polyimide film 13, the upper polyimide film 14, and the wiring layer 12 formed therebetween as described above.
Since the entire thickness is about several μm, even if it is bent with a small radius of curvature, there is no disconnection.

By arranging the electrode section 3 on the side of the lens frame of the objective lens 16 in this manner, a substantial contact sensor 1 for securing a space for connecting a lead wire for connecting to an external controller is provided. Can be prevented from increasing in thickness.

Therefore, the contact sensor 1 of the present embodiment can be applied to a high-magnification objective lens in which the distance between the forefront lens 18 of the objective lens 16 and the object is very small.

Next, the operation of the contact sensor 1 according to the present embodiment will be described.

In the sensor section 5 having the structure shown in FIG. 2, the area 11 below the projection 8 as a pressure receiving section is supported by the main body 2 made of a thin semiconductor plate such as n-type single crystal silicon. Since the beam is a cantilever, a bending stress acts on the sensor element 10 when an object comes into contact with the projection 8 as a pressure receiving portion.

At this time, the piezoresistive elements 10a and 10a
A tensile strain acts on c in the same direction as the current path,
Tensile strain acts on the piezoresistive elements 10b and 10d in a direction orthogonal to the current path.

As described earlier in the description of the method of manufacturing the contact sensor 1 according to the present embodiment, the sensor unit 5
Even if a thin film having a low elastic modulus such as a polyimide film remains in the notch (opening) portion 9 of the above, the rigidity thereof is sufficiently smaller than the rigidity of the region 11 made of a semiconductor thin plate such as n-type single crystal silicon. In this case, the projection 8 as the pressure receiving portion
The operation in which a bending stress acts on the sensor element 10 due to the contact of the object with the object does not significantly deteriorate.

By the way, the plane orientation of the main current path formed on the silicon substrate 101 whose main surface is <100> is <1.
The gauge factor of the low-concentration p-type diffusion layer of 10> shows the maximum value,
For example, the document “Properties of Sili”
con "(ISBN0 85296 4757), the distortion in the same direction as the current path is +121.
-112. Against distortion in the direction orthogonal to the current path
0.

That is, when an object comes into contact with the projection 8 as a pressure receiving portion, the resistance values of the piezoresistive elements 10a and 10c increase, and the resistance values of the piezoresistive elements 10b and 10d decrease.

For this reason, the four piezoresistive elements 10a,
In combination with the fact that the gauge factors of 10b, 10c and 10d are very large as compared with metal thin films, etc., these 4
Piezoresistive elements 10a, 10b, 10c and 10d
Complementary and highly sensitive strain measurement can be performed by configuring a bridge circuit with. As a result, the contact sensor 1 can also detect stress caused by very small contact.

As described above, when manufacturing the contact sensor 1 according to the present embodiment, the photolithography technique used for manufacturing the integrated circuit can be applied, so that the four piezoresistive elements 10a, 10b, 10c
And 10d can be arranged finely and close to each other, and the four piezoresistive elements 10a, 10b, 10c, 1
Since the temperature difference between 0d can be made very small,
The influence of the temperature drift on the stress detection as the sensor unit 5 can be extremely reduced.

As described above, the sensor unit 5 of the present embodiment
Very small contact stress can be detected stably with respect to changes in ambient temperature.

Further, in the contact sensor 1 of the present embodiment,
As shown in FIG. 6, when assembled to the objective lens 16 of the microscope, the projections 8 as the pressure receiving portions of the eight sensor units 5 are formed around the frontmost lens 18 of the objective lens 16. Therefore, the object and the lens frame front surface 1 of the objective lens 16
Even when the object 7 is not strictly parallel, the projection 8 as a pressure receiving part of one of the sensor units 5 contacts the object before the object contacts the frontmost lens 18 of the objective lens 16. , The contact can be detected.

As described above, the contact sensor 1 of the present embodiment can detect a contact even with a very small stress. Therefore, the contact sensor 1 avoids the contact or stops the focusing operation of the objective lens 16 immediately after the contact is detected. By the way,
It is possible to extremely reduce the damage to the object due to the contact.

In addition, in the configuration of the present embodiment,
Thickness (t1) of region 11 made of a semiconductor thin plate such as n-type single crystal silicon on which projection 8 as a pressure receiving portion is formed.
Is thinner than the thickness (t2) of the main body 2 made of a semiconductor thin plate made of n-type single crystal silicon or the like, so that not only the strain is caused by a smaller stress but also the objective lens 16
When attached to the front surface 17 of the lens frame, the clearance for the operation of the protrusion 8 as the pressure receiving portion can be secured without using a special spacer, and the thickness of the sensor can be substantially reduced.

Further, by incorporating a time division circuit, an amplifier circuit, and the like in the electronic circuit 6 disposed on the electrode unit 3 attached to the side of the lens frame of the objective lens 16, a plurality of sensor units 5 are provided.
, The connection with the external controller functions with a minimum number of wires such as a power supply line, a signal line, and a clock line.

Further, by arranging the amplifier circuit close to the contact sensor 1, it is possible to realize contact detection with a high S / N.

Further, since the sensor unit and the circuit unit are substantially formed integrally, the size of the apparatus can be reduced. Therefore, the size of the lens frame such as the objective lens 16 is unnecessarily increased. Never.

In the present embodiment, the electronic circuit 6 is
Although it is arranged on the electrode part 3 formed integrally with the main body part 2,
Needless to say, it can be incorporated in the main body 2 if there is sufficient space.

In the present embodiment, an example in which the contact sensor 1 is applied to the objective lens 16 of a microscope has been described. However, it can be widely applied to various devices that operate close to an object. Needless to say.

(Second Embodiment) Next, a second embodiment of the present invention will be described.
The contact sensor according to the embodiment will be described with reference to FIG.

The contact sensor according to the second embodiment of the present invention is basically the same as the above-described first embodiment, but differs only in the configuration of the sensor unit.

That is, in the present embodiment, as the sensor portion 5 ', a projection 8 as a pressure receiving portion is formed on the main body portion 2 made of a semiconductor thin plate of n-type single crystal silicon or the like. A notch (opening) 9 'is formed.

In this case, the thickness (t1) of the region 11 'made of a semiconductor thin plate of n-type single-crystal silicon or the like formed immediately below the projection 8 as a pressure-receiving portion is equal to the surrounding n-type single-crystal. It is formed thinner than the thickness (t2) of the main body 2 made of a semiconductor thin plate such as silicon.

In the vicinity of the projection 8 as a pressure receiving portion, piezoresistive elements 10a 'and 10
b ', 10c', and 10d 'are formed so as to form four sides of a square.

As can be seen from FIG. 7, in the first embodiment, the region 11 of the sensor portion 5 'is formed of a cantilever, whereas in the present embodiment, the region 11' of the sensor portion 5 'is formed.
Is supported by a doubly supported beam.

In this configuration, as compared with the first embodiment, the sensitivity to the contact stress is inferior, but the mechanical strength when a large stress is applied to the projection 8 as a pressure receiving portion from the side or obliquely is high. Therefore, it is suitable for applications in which a relatively strong stress may be applied to the sensor unit 5 'for cleaning or the like.

In the present specification described in the above embodiments, in addition to claims 1 to 3 described in the appended claims, the inventions shown below as additional notes 1 to 6 are described. include.

(Supplementary Note 1) A thin plate made of a semiconductor, a flexible thin film provided on the thin plate, a protrusion provided on the flexible thin film, and a thin plate provided on the thin plate and the flexible thin film A contact sensor provided on the thin plate made of the semiconductor in the vicinity of the protrusion and detecting a force acting on the protrusion.

(Corresponding Embodiment) The first and second embodiments correspond to this.

(Function and Effect) The main body 2 made of a semiconductor thin plate
, Notches (openings) around the plurality of protrusions 8
9 is formed, and the sensor section 10 as a strain sensor is arranged close to the projection section 8, so that when the projection section 8 comes into contact with an object and stress is generated, the sensor section 10 is distorted. Occurs, and contact of the object is detected.

As described above, the contact sensor for detecting the contact of the object is formed of a semiconductor thin plate by detecting the contact of the object with the protrusion and the generation of stress by the strain sensor. Since the sensor itself can be made extremely thin and a plurality of projections are formed, even when the object and the device on which the contact sensor is assembled are not strictly parallel, the projection can be performed through any one of the projections. Thus, it is possible to detect contact of the object.

(Supplementary Note 2) The opening is formed at a position opposite to both sides of the projection, and the area immediately below the projection by the opening is doubly supported by a peripheral thin plate made of the semiconductor. The contact sensor according to claim 1, wherein the contact sensor is supported as:

(Corresponding Embodiment) The second embodiment corresponds to this.

(Function and Effect) The region 11 'in which the projection 8 as the pressure receiving portion is formed constitutes a doubly supported beam whose both ends are supported by the main body 2 made of a surrounding single crystal silicon thin plate.

Since the region 11 'is a doubly supported beam as described above, the region 11' is easily deformed by the stress applied to the projection 8 as a pressure receiving portion, and the piezoresistive elements 10a 'and 10'
In the sensor element as a strain sensor composed of b ', 10c', and 10d ', a large output signal is obtained for a relatively small stress.

In addition, since the region 11 'has a high mechanical strength, the region 11' is not easily broken even when a large force acts on the projection 8 as a pressure receiving portion for the purpose of cleaning or the like.

(Appendix 3) The contact sensor according to claim 1 or 2, wherein the thin plate made of a semiconductor is formed by electrochemically etching a single crystal silicon substrate.

(Corresponding Embodiment) The first embodiment corresponds to this.

(Function and Effect) The main body 2 of the contact sensor 1
N-type diffusion layer 10 formed on p-type single crystal semiconductor substrate 101
3 is formed by applying a bias to perform electrochemical etching in an alkaline aqueous solution.

Thus, the thickness of the region in which silicon remains is determined by the junction depth of n-type diffusion layer 103 and the width of a depletion layer extending therefrom to p-type substrate 101 or p-type diffusion layer 103. However, the thickness can be strictly controlled to, for example, about 10 μm by applying an n-type impurity to the diffusion layer, applying a thermal diffusion process, and applying an electrochemical etching voltage.

By forming the main body portion 2 of single crystal silicon thin in this way, the stress on the projection 8 as the pressure receiving portion can be detected with high sensitivity, and the thickness of the entire sensor can be reduced. Can be.

(Supplementary Note 4) The strain sensor has a structure in which a P-plane formed on a single-crystal silicon substrate whose main surface has a plane orientation of <100>.
And a current path of at least one of the resistance elements is along a <110> crystal orientation of the single crystal silicon substrate, and a current path of the other resistance element is 3. The contact sensor according to claim 2, wherein the path is orthogonal to the <110> crystal orientation.

(Corresponding Embodiment) The first embodiment corresponds to this.

(Function and Effect) The piezoresistive elements 10a, 10b, 10c and 10d serving as strain sensors are each formed of a p-type diffusion layer formed on a single-crystal semiconductor substrate having a <100> principal plane. The current paths of the piezoresistive elements 10a and 10b are orthogonal to the current paths of the piezoresistive elements 10b and 10d.

The current paths of the piezoresistive elements 10a and 10b are along the <110> crystal orientation.

The gage factor of the low-concentration p-type diffusion layer whose main plane is <110> and whose main plane is <110> has a maximum value, which is a single crystal semiconductor substrate whose main plane is <100>. Is shown.

That is, when an object comes into contact with the projection 8 as the pressure receiving portion, the resistance values of the piezoresistive elements 10a and 10c increase, and the resistance values of the piezoresistive elements 10b and 10d decrease.

For this reason, the gage factor of each of the piezoresistive elements 10a, 10b, 10c, and 10d serving as strain sensors is extremely large as compared with a metal thin film or the like.
These four piezoresistive elements 10a, 10b, 10c,
By configuring a bridge circuit with 10d, complementary and high-sensitivity strain measurement becomes possible, and as a result, it is possible to detect stress caused by very small contact.

(Supplementary note 5) The contact sensor according to any one of Supplementary notes 1 to 4, wherein the signal processing circuit of the strain sensor is formed integrally on a thin plate made of the semiconductor.

(Corresponding Embodiment) The first embodiment corresponds to this.

(Function and Effect) An electronic circuit 6 including a time division circuit and an amplification circuit of a plurality of sensor units 5 constituting a strain sensor is formed integrally with the main body 2 of the contact sensor 1 as a strain sensor. I have.

Since the time division circuit and the amplifier circuit are built in the electronic circuit 6 arranged in the electrode section 3, even if the strain sensor has a plurality of sensor sections 5,
The connection with the external controller is made by power line, signal line,
Works with a minimum number of wires, such as clock lines.

Further, by arranging the amplifier circuit close to the contact sensor 1, it is possible to realize contact detection with a high S / N.

Further, since the sensor unit and the circuit unit are substantially formed integrally, the size of the apparatus can be reduced. Therefore, the size of the lens frame such as the objective lens 16 is unnecessarily increased. Never.

(Supplementary Note 6) An electrode for connecting a lead wire for connection to an external controller is formed of a flexible thin film integrally formed with a thin plate made of the semiconductor, and is formed of a flexible thin film integrally formed with the semiconductor formed with the strain sensor. 6. The semiconductor device according to claim 1, wherein the wiring is formed in the flexible thin film and is separated from the thin plate by a wiring layer. Contact sensor.

(Corresponding Embodiment) The first embodiment corresponds to this.

(Function and Effect) The electrode portion 3 on which the external lead electrode 7 is formed is the same as the body portion 2 on which the plurality of sensor portions 5 are formed.
And the flexible thin film portion 4 and are electrically connected by wiring in the flexible thin film.

A lead wire for connecting to an external controller is connected to the external lead electrode 7 of the electrode section 3.

As described above, the flexible thin film portion 4 is composed of the lower polyimide film 13, the upper polyimide film 14, and the wiring layer 12 formed therebetween, but the total thickness is about several μm. Therefore, even if it bends so that a very strong stress acts with a small curvature, it does not break.

By arranging the electrode section 3 on the side of the lens frame of the objective lens 16 in this manner, a substantial contact sensor can be provided to secure a space for connecting a lead wire for connection to an external controller. An increase in thickness can be prevented.

Therefore, the contact sensor 1 according to the present invention can be applied to a high-magnification objective lens in which the distance between the frontmost lens 18 of the objective lens 16 and the object is very small.

[0132]

According to the first aspect of the present invention, the contact sensor detects the contact of the object by detecting the stress generated by the object coming into contact with the projection by the strain sensor. Since the sensor is formed of a semiconductor thin plate, the sensor itself can be extremely thin, and since a plurality of projections are formed, the object and the device in which the contact sensor is assembled are not strictly parallel. However, it is possible to detect the contact of the object through any of the protrusions.

According to the second aspect of the present invention, since the region where the protrusion and the strain sensor are formed is formed thinner than the surrounding thin plate made of a semiconductor such as single crystal silicon, the contact area is reduced. Even if the sensor mounting surface is a simple flat surface, the operation clearance of the protrusion as the pressure receiving part is secured without requiring a special spacer etc.,
The substantial thickness of the contact sensor can be reduced.

According to the third aspect of the present invention, the area where the protrusion and the strain sensor are formed constitutes a cantilever whose one end is supported by a thin plate made of a surrounding semiconductor. Since the projection is easily deformed by the stress applied to the projection, a large output signal can be obtained for a relatively small stress in the strain sensor.

Therefore, as described above, according to the present invention, it is possible to provide an extremely thin contact sensor that can be arranged in a very narrow space.

[Brief description of the drawings]

FIG. 1 shows a structure of a contact sensor according to a first embodiment of the present invention, and FIG. 1A is a plan view of the contact sensor according to the first embodiment; FIG. 1B is a cross-sectional view taken along the line AA ′ in FIG.

FIG. 2 is an enlarged view of a sensor unit 5 of FIG.

FIG. 3 is an enlarged view of the sensor element 10 of FIGS. 1 and 2; FIG. 3A is a plan view of the sensor element 10; FIG. A- in FIG.
It is A 'sectional drawing.

FIGS. 4A to 4C are process diagrams for describing a method of manufacturing the contact sensor 1 according to the first embodiment.

FIGS. 5A to 5C are process diagrams for describing a method of manufacturing the contact sensor 1 according to the first embodiment.

FIG. 6 is a contact sensor 1 according to the first embodiment;
FIG. 3 is a view showing a state where the is assembled to an objective lens 16 of a microscope.

FIG. 7 shows a structure of a contact sensor according to a second embodiment of the present invention, and is an enlarged view of a sensor unit 5 in particular.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Contact sensor, 2 ... Annular main-body part which consists of semiconductor thin plates, such as n-type single crystal silicon, 3 ... Electrode part which consists of semiconductor thin plates, such as n-type single crystal silicon, 4 ... n-type single crystal silicon A flexible thin film portion made of a semiconductor thin plate such as 5; a sensor portion; 6 an electronic circuit; 7 a plurality of external lead electrodes; 8 a protrusion as a pressure receiving portion; 9 a notch (opening) portion; Sensor element, 10a, 10b, 10c, 10d: Piezoresistive element, 11: Area, 12: Wiring layer, 13: Lower polyimide film, 14: Upper polyimide film, 15: Contact hole, 101: Plane orientation of main surface is <100> a low-concentration p-type semiconductor substrate; 102, a p-type diffusion layer having a higher concentration than the substrate; 103, an n-type diffusion layer; 104, a relatively high-concentration p-type diffusion layer; 105, a silicon nitride film; Silicon oxide film 16: Objective lens, 17: Front lens frame of the objective lens, 18: Lens on the forefront of the objective lens, 5 ': Sensor part, 9': Notch (opening) part, 11 ': Area, 10a ', 10b', 10c ', 10d' ... piezoresistive elements.

Claims (3)

[Claims] 1. A protrusion provided on a thin plate made of a semiconductor, an opening around the protrusion, provided on the thin plate made of a semiconductor, provided near the protrusion and acting on the protrusion. And a strain sensor for detecting a force to be applied by strain of the thin plate made of the semiconductor. 2. The contact sensor according to claim 1, wherein a thin plate made of the semiconductor is thinner immediately under the protrusion than at a peripheral portion. 3. The semiconductor device according to claim 2, wherein the opening is formed so as to surround the projection, and the area immediately below the projection is supported as a cantilever from a peripheral thin plate made of the semiconductor by the opening. The contact sensor according to claim 1 or 2, wherein