JPH11183414A - Scanning heat transfer distribution measuring device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To measure the heat transfer distribution of a minute region on a sample surface. SOLUTION: A cantilever 1 comprises a probe 1b and a thermocouple at its tip part 1a and can be elastically deformed. A laser light source 4 irradiates the tip part 1a with intensity-modulated laser light, and the probe 1b is subjected to AC heating. A thermo-electromotive force amplifier 10 amplifies a thermo- electromotive force detected by the thermocouple of the probe 1b and outputs it to a lock-in amplifier 13. The lock in amplifier 13 detects only the same thermo-electromotive force as a reference frequency component with the modulation frequency of a laser power source 11 as the reference frequency. A position sensor 5 detects the bending of the cantilever 1 by an optical lever method, outputs it to a computer 14 via an I-V converter 8 and an amplifier 9. The computer 14 performs feedback control via a driving device 12 to control the location of a sample 15. The computer 14 stores the location of the cantilever 1 and the temperature changes of the probe 1b and obtains the surface shape and the heat transfer distribution of the sample.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for scanning a probe by heating the tip of the probe and bringing the probe into contact with the surface of the sample. The present invention relates to a scanning type heat conduction distribution measuring device capable of measuring the heat conduction distribution of a semiconductor device.

[0002]

2. Description of the Related Art Conventionally, there is a thermal conduction distribution measuring apparatus using a probe formed by processing a Wollaston wire (see "Scanning Near-Film and Scanning Near-Film Optical Microscope").
eld Optical Microscopy and Scannig Thermal Microsc
opy) ": Russel j. Pylkki and others: Jpn. J. Appl. Phys. Vo
l.33 (1994) pp.3785-3790). The Wollaston wire is composed of a platinum (Pt) core surrounded by silver pods. The Wollaston wire is bent into a loop and etched to expose the core platinum in order to be used as a probe for measuring the thermal conductivity distribution of the sample. When the Wollaston wire is energized, the resistance of the platinum portion of the core is high, so that the platinum portion generates heat and is maintained at a certain temperature which is several tens degrees higher than room temperature. This Wollaston wire is scanned along the surface of the sample by contacting or approaching the surface of the sample to be measured.
Because the flow of heat in Wollaston Wire changes, the resistance changes as the temperature of Wollaston Wire changes. Using this principle, the resistance of the Wollaston wire is measured while scanning the Wollaston wire over the sample surface, thereby measuring the heat conduction distribution on the sample surface. Alternatively, the heat conduction distribution on the sample surface is similarly measured by measuring the amount of current applied to the Wollaston wire so that the resistance becomes constant.

[0003]

However, in the above-described scanning type thermal conductivity distribution measuring apparatus using a probe formed of a Wollaston wire, the probe is heated by applying a DC current to the Wollaston wire. ,
There has been a problem that the temperature of the probe changes due to environmental fluctuation and drift at the time of measurement, and measurement accuracy deteriorates.

Further, in the above-described probe formed by processing the Wollaston wire, a portion where the Wollaston wire is etched is used as a probe tip, and this probe can obtain a heat conduction distribution in a minute area on the sample surface. As much as you can
Not sharp enough.

Further, a probe having a stable shape cannot be obtained due to variations in the way of bending Wollaston wires or etching, and bending of Wollaston wires and the like must be performed manually one by one to manufacture a probe. In addition, there was a problem that production efficiency was poor.

Accordingly, an object of the present invention is to provide a scanning type heat conduction distribution measuring apparatus which can eliminate such a problem and can measure the heat conduction distribution in a minute area of a sample surface with high accuracy. .

[0007]

According to a first aspect of the present invention, an elastically deformable cantilever having a probe at a tip and a temperature sensor thermally coupled to the probe is provided, and the probe is brought into contact with a sample surface. Scanning means for relatively scanning the cantilever and the sample, a heating means for heating the probe while periodically changing the heating amount with time, and a cycle among the temperatures detected by the temperature sensor. And a temperature detecting means for detecting a temperature change which changes gradually.

In such a configuration, the probe is heated while periodically changing the heating amount with the passage of time, and the temperature detecting means determines the temperature detected by the temperature sensor.
A temperature change that changes periodically is detected. In this way, changes in the measurement environment and DC drift components are removed, and the change in heat flowing from the probe to the sample, that is, the temperature difference due to the difference in heat supply between the heat supply to the probe and the heat conduction to the sample. Only changes can be measured, and high resolution and high precision measurement can be performed.

According to a second aspect of the present invention, in the first aspect, the heating means irradiates a laser beam near the probe and changes the light intensity applied to the probe periodically with time. The amount of heating of the probe is periodically changed.

For this reason, the probe can be heated at any desired position on the tip of the cantilever near the probe,
By changing the light intensity, the amount of heating can be changed.

In a third aspect based on the second aspect, the apparatus further comprises a position sensor for detecting the deflection of the cantilever based on the reflection of the laser beam irradiated by the heating means and detecting the unevenness of the sample. It is characterized by the following.

Thus, the laser light source for position detection and the laser light source for heating can be shared by one laser light source, and the configuration of the apparatus can be simplified.

According to a fourth aspect, in the first aspect, the heating means is provided on the cantilever, and the heating means includes a heating element whose heating amount changes periodically when a periodically changing voltage is applied. It is characterized by having.

Therefore, the probe can be heated at any desired position near the tip of the cantilever,
By changing the voltage applied to the heating element, the amount of heating to the probe can be changed.

According to a fifth aspect, in the first to fourth aspects, the temperature sensor is a thermocouple.

Therefore, a wide range of temperature change can be measured.

According to a sixth aspect of the present invention, in the first to fifth aspects, the cantilever including the tip is a thin film element thinned by a semiconductor manufacturing technique.

As a result, cantilevers having the same shape and the same performance can be mass-produced using a semiconductor process, and the production efficiency can be improved.
Particularly, a sharp probe shape can be manufactured uniformly and stably, so that measurement with high resolution is possible.

According to a seventh aspect, in the first to sixth aspects, the scanning means relatively moves the cantilever and the sample by moving a sample support on which the sample is placed. It is characterized by.

As a result, the cantilever side is fixed,
It is possible to stably scan the cantilever without affecting position detection and temperature detection.

[0021]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a configuration of a scanning heat conduction distribution measuring device according to a first embodiment of the present invention. In FIG. 1, the cantilever 1 is elastically deformable, is attached to a lever holder 2, and a probe 1 b at a tip 1 a of the cantilever 1 can be brought into contact with a sample 15. Although the configuration of the cantilever 1 itself will be described later,
The probe 1b includes a thermocouple that is thermally coupled, and the thermocouple functions as a temperature sensor of the probe 1b. The lever holder 2 is fixed to the lever support 6 by a connecting member 2a.

A laser light source 4 for irradiating the upper surface of the tip 1a of the cantilever 1 with laser light and a reflection of the laser light emitted from the laser light source 4 for reflecting on the upper surface of the tip 1a are provided on the lower surface of the lever support portion 6. Each of the position sensors 5 for receiving light is attached.

The laser light source 4 is connected to a laser power supply 11. The laser power supply 11 has a predetermined frequency, for example, 10
The laser light source 4 is driven so that the intensity is modulated at 0 Hz. The intensity-modulated laser light from the laser light source 4 is applied to the tip 1a of the cantilever 1, and as a result, the probe 1b is AC-heated. Note that “AC heating” used in the present specification means heating such that the temperature of the probe 1b changes periodically with time. Therefore, in the embodiment of the present invention, a heat source is used. A certain laser light source is intensity-modulated at a certain cycle. The waveform to be modulated may be anything, and may be any shape such as a sine wave and a triangular wave. Incidentally, the laser light source 4 is, for example, He-N
It can be realized by a gas laser such as an e-laser or a solid-state laser such as a semiconductor laser, but is not limited thereto.

The position sensor 5 detects the displacement of the reflected light from the cantilever 1 and outputs the detected current signal to the I
The signal is converted into a voltage signal by a -V converter 8. The converted voltage signal is amplified by the amplifier 9, and the amplified signal is input to the computer 14. The detection of deflection of the cantilever 1 during scanning by the position sensor 5 can be realized by a known optical lever method. In the case of using the optical lever method, the position sensor 5 is realized by a two-part photodetector, and detects the amount of bending of the cantilever 1 based on the light intensity of the reflected light detected by the two-part photodetector.

On the other hand, the thermocouple forming the probe 1b is connected to the thermoelectromotive force amplifier 10 and amplifies the thermoelectromotive force from the thermocouple. The voltage signal amplified by the thermoelectromotive force amplifier 10 and the signal of a predetermined frequency from the laser power supply 11 are input to the lock-in amplifier 13. Here, since the lock-in amplifier 13 can select and detect a signal of a specific frequency in particular, a small signal or DC
This is effective for a signal having a change (drift). The lock-in amplifier 13 detects only a signal having the same frequency as the predetermined frequency among the voltage signals amplified by the thermoelectromotive force amplifier 10 using the signal of the predetermined frequency from the laser power supply 11 as a reference signal. Amplify. Specifically, a change in the amplitude of the signal having the predetermined frequency is detected and input to the computer 14 as a DC output. Thereby, the influence of the change of the measurement environment and the drift is removed, and the temperature change can be detected with high accuracy. Note that the thermoelectromotive force amplifier 10
Is provided because the signal detected by the thermocouple is actually on the order of μV. It is not necessary.

The sample 15 is set on the sample support 7 on the sample movable section 3. The sample movable section 3 is connected to a driving device 12. By driving the driving device 12, the probe 1 b of the cantilever 1 performs scanning in a direction parallel to the sample surface and moves in a direction perpendicular to the sample surface. And make proper contact with the sample surface. In other words, the probe 1b of the cantilever 1 is moved relatively to the sample by driving the sample movable section 3, and the position and contact relationship of the probe 1b of the cantilever 1 on the sample surface are appropriately controlled. I do.

The computer 14 controls the lock-in amplifier 1
The heat conduction distribution on the sample surface is determined based on the detection output input from the sensor 3 and the contact plane position of the probe 1b, and is output to the outside. Further, the computer 14 calculates a voltage based on the voltage signal input from the amplifier 9 and the contact plane position of the probe 1b.
The uneven shape of the sample surface based on the amount of deflection of the cantilever 1 can be obtained. Alternatively, a feedback process for driving the sample movable section 3 in a direction perpendicular to the sample surface is performed via the driving device 12 so as to cancel the bending of the cantilever 1. Thus, the uneven shape of the sample surface can be obtained by measuring the feedback amount controlled so that the cantilever 1 does not bend.

The control procedure of the computer 14 will be described. The computer 14 first moves the probe 1b of the cantilever 1 to a desired horizontal position on the surface of the sample, and at this horizontal position, the probe 1b comes into contact with the surface of the sample. As described above, the sample movable section 3 is driven via the driving device 12. At this time, the laser light is emitted from the laser light source 4 to the tip 1a of the cantilever 1, and the deflection of the cantilever 1 is detected by the position sensor 5 from the reflected light. Therefore, the computer 14 determines whether the probe 1b is properly in contact with the sample surface by detecting the deflection of the cantilever 1 from the position sensor 5 via the IV converter 8 and the amplifier 9. can do. When the computer 14 scans the surface of the sample with the probe 1b appropriately in contact with the surface of the sample, the computer 14 determines the current amount of movement of the sample movable unit 3 in the horizontal and vertical directions instructed by the drive unit 12. The surface shape of the sample 15 is obtained by sequentially obtaining and storing the three-dimensional position of the probe 1b as coordinates.

On the other hand, when scanning of the probe 1b starts, the computer 14 measures the surface shape of the sample 15 in parallel with the measurement.
The thermal conductivity on the surface parallel to the sample surface is measured by sequentially obtaining and storing the thermal conductivity on the scanned sample surface. That is, the tip 1a of the cantilever 1 is irradiated with the intensity-modulated laser light emitted from the laser light source 4, so that the probe 1b is AC-heated, and the AC-heated probe 1b comes into contact with the sample. Therefore, heat is absorbed by the sample by heat conduction. As a result, the temperature of the probe 1b changes depending on the magnitude of the thermal conductivity of the sample surface. If the thermal conductivity of the sample surface is high, the temperature of the probe 1b drops significantly, and if the thermal conductivity of the sample surface is low, the probe is detected. The temperature of the needle 1b decreases less. Since the probe 1b is formed of a thermocouple, a change in temperature causes a change in the thermoelectromotive force of the thermocouple, and the thermoelectromotive force is input to the lock-in amplifier 13 via the thermoelectromotive amplifier 10 and the laser light. Are detected only at the same frequency as the intensity modulation, and are sequentially input to the computer 14. Accordingly, the computer 14 sequentially obtains the current two-dimensional position of the terminal 1 b as coordinates based on the horizontal movement amount of the sample movable unit 3 instructed by the drive device 12, and also calculates the heat input from the lock-in amplifier 13. The thermal conductivity of each sample is measured by sequentially obtaining and storing the thermal conductivity at each coordinate based on the temperature change indicated by the electromotive force.

Of course, since the surface shape and the heat conduction distribution of the sample 15 are measured at the same time, the computer 14 can perform an output in which the surface shape and the heat conduction distribution are superimposed on each other. Display output may be performed using graphics.

Here, referring to FIG. 2, cantilever 1
Will be described. FIG. 2A is a perspective view of the cantilever 1, and FIG.
FIG. 4 is a cross-sectional view taken along a line A. As shown in FIG. 2B, the cantilever 1 has a beam 22 made of an elastic body, a support 24 supporting the beam 22, and outer surfaces opposed to each other with the beam 22 and the support 24 interposed therebetween. A thermocouple composed of the first and second metal films 25 and 26 formed and the first and second metal films 25 and 26 protruding from the end of the beam 22 opposite to the support 24 is provided. And a probe 21.

Since the first and second metal films 25 and 26 are materials forming a thermocouple, they need to be a combination of metals forming a thermocouple. For example, the first
By using chromel as the metal and alumel as the second metal, a chromel-alumel thermocouple can be formed. Of course, selection of a combination of metals constituting the thermocouple requires a suitable electromotive force at a temperature in the measurement range.

The beam 22 is made of silicon nitride, and the support 24 is made of silicon. The first metal film 25 forms a strip-shaped wiring pattern 25 b from the probe 21 to the center of the upper surface of the support 24, and further forms the support 2.
4, a square electrode pattern 25 a is formed in the center of the upper surface. Further, a film having a shape facing the first metal film 25 is also formed by the second metal film 26.

Next, a method of manufacturing the cantilever 1 will be described with reference to FIG. 3 (a) to 3 (d)
3 is a cross-sectional view illustrating a manufacturing process of the cantilever 1. FIG. First, a diameter of 3 inches and a thickness of 250μ covered with a natural oxide film
Silicon nitride films 31a and 31b are formed on both surfaces of an n-type silicon substrate 30 having m and (100) orientations by low pressure vapor phase epitaxy using dichlorocyanide and ammonia gas as raw materials.
0 nm was formed. Further, the silicon nitride film 31 on the substrate 30
By partially patterning a by photolithography and dry etching, a square opening h exposing the surface of the substrate 30 is formed at a predetermined position of the silicon nitride film 31a on the upper surface of the substrate 30. One side of the removed square is 5 to 10 μm. Here, the shape of the opening h is square, but the pattern shape and size thereof can be set arbitrarily. Thereafter, the substrate is treated with an aqueous solution of potassium hydroxide (KOH) or tetramethylammonium hydroxide (TM).
AH) The silicon nitride film 31a, 31b is immersed in a silicon etchant such as an aqueous solution, and the portion of the substrate 30 exposed from the opening h is anisotropically etched in a square pyramid shape using the silicon nitride films 31a and 31b as a mask. A quadrangular pyramid-shaped trench hh which is continuous with h is formed (FIG. 3A). The substrate 30
Because the (100) plane orientation is used as
As is well known, the etching is automatically stopped at the silicon (111) plane depending on the crystal direction.
The plane h is a tapered plane having an angle of 54.7 degrees.

Thereafter, the substrate in the state shown in FIG. 3A is placed in an electric furnace and heated, and the trench h of the exposed substrate 30 is exposed.
A silicon oxide film 32 is grown by thermal oxidation on the portion h.
As is well known, the growth rate of the silicon oxide film is fast in a flat portion and slow in a corner portion.
The sectional shape of No. 2 is as shown in FIG. 3B, and the thickness of the bottom is extremely thin as compared with other portions. Thereafter, the shape of the cantilever 1 is patterned on the surface of the substrate in this state, and the shape of the support 24 is patterned on the back surface of the substrate. On the surface of this substrate, gold, platinum,
The first metal film 33 forming a thermocouple of nichrome, chromel, alumel, platinum rhodium, nickel or the like is patterned (FIG. 3B).

Further, the substrate in the state shown in FIG.
The substrate is immersed in an aqueous solution of potassium hydroxide heated to 85 ° C. at a concentration of wt% to elute only unnecessary silicon portions, thereby forming a cantilever 1 in a cantilever state. Note that the silicon oxide film 32 corresponding to the probe 1b is removed by etching, exposing the first metal film 36 constituting the probe 1b (FIG. 3C).

Thereafter, unlike the first metal film 33 previously formed on the rear surface of the substrate, the second metal film 3 forming a thermocouple is formed.
4 is formed. As a result, a thermocouple having the probe 37 serving as a temperature measuring contact is formed in the distal end region 35 of the cantilever 1 (FIG. 3D). As a result, the tip of the probe 37 becomes sharp with a very small radius of curvature, and enables measurement of the heat conduction distribution at the molecular and atomic levels.

The thinned cantilever manufactured in this manner has mechanical strength and can efficiently manufacture a large number of cantilevers having the same shape and the same quality. In addition, since the semiconductor manufacturing method is used, the heat capacity of the probe portion forming the thermocouple is small, so that even if the irradiated laser beam is modulated by a high frequency, it can follow the high-frequency AC heating change. Can be.

When the cantilever 1 manufactured as described above is applied to the scanning type heat conduction distribution measuring apparatus shown in FIG. 1, the probe 1b of the cantilever 1 is moved by laser light to A
Since the position sensor 5 can also use the light reflected by the cantilever 1 while being heated by C, the overall device structure is simplified.

Next, a second embodiment will be described. In the first embodiment described above, the probe 1b of the cantilever 1 is AC-heated by modulating the laser beam from the laser light source 4, but in the second embodiment, the probe of the cantilever 1 is searched. A heating element is integrally formed near the needle 1b, and the heating element is directly subjected to AC heating.

FIG. 4 shows a configuration of a scanning type heat conduction distribution measuring apparatus according to a second embodiment of the present invention. 4, the same components as those in FIG. 1 are denoted by the same reference numerals. 4 is different from the scanning type heat conduction distribution measuring apparatus shown in FIG. 1 in that a cantilever 41 is attached instead of the cantilever 1 and a heater power supply 42 is used instead of the laser power supply 11. Differently, other configurations are the same.

Although the detailed configuration of the cantilever 41 will be described later, the cantilever 41 has a heating element at the tip 41a in addition to the configuration of the cantilever 1. This heating element
It is formed integrally with the cantilever 41 and is connected to a heater power supply 42 for AC heating. Therefore, in the first embodiment, the AC heating is performed by the laser light from the laser light source 4, whereas in the second embodiment, the heating element is AC heated by applying the voltage of the heater power supply 42.

In FIG. 4, the computer 14 first moves the probe 41b of the cantilever 41 to a desired horizontal position on the sample surface, and further moves the probe 4b at this horizontal position.
The sample movable section 3 is vertically driven via the driving device 12 so that 1b contacts the sample surface. At this time, the laser light is emitted from the laser light source 4 to the tip 1a of the cantilever 1, and the deflection of the cantilever 1 is detected by the position sensor 5 using the reflected light. Therefore, the computer 14 determines whether the probe 41b is appropriately in contact with the sample surface by detecting the bending of the cantilever 1 from the position sensor 5 via the IV converter 8 and the amplifier 9. can do. Computer 1
4 is a state where the probe 41b is appropriately in contact with the sample surface,
When scanning over the sample surface, the current three-dimensional position of the probe 41b is sequentially obtained as coordinates based on the horizontal and vertical movement amounts of the sample movable unit 3 instructed to the drive device 12, and stored. The surface shape of the sample 15 is determined.

On the other hand, when the scanning of the probe 41b starts, the computer 14 sequentially obtains and stores the thermal conductivity on the scanned sample surface in parallel with the measurement of the surface shape of the sample 15, thereby storing the sample surface. Measure the heat conduction distribution on a plane parallel to. That is, the heating element at the distal end 41a of the cantilever 41 is AC-heated by the application of the voltage modulated by the heater power supply 42, whereby the probe 41b is also heated by AC.
Since the heated and heated AC probe 41b is in contact with the sample, heat is absorbed by the sample by heat conduction. As a result, the temperature of the probe 41b changes depending on the magnitude of the thermal conductivity of the sample surface. If the thermal conductivity of the sample surface is high, the temperature of the probe 41b drops significantly, and if the thermal conductivity of the sample surface is low, the probe is detected. The temperature of the needle 41b decreases only slightly. Since the probe 41b is formed of a thermocouple, a change in temperature causes a change in the thermoelectromotive force of the thermocouple, and the thermoelectromotive force is input to the lock-in amplifier 13 via the thermoelectromotive amplifier 10 and the heater power supply. The thermoelectromotive force of only twice the modulation frequency of 42 is detected and sequentially input to the computer 14. Therefore, the computer 14 sequentially obtains the current two-dimensional position of the terminal 41b as coordinates based on the horizontal movement amount of the sample movable unit 3 instructed by the driving device 12, and
The thermal conductivity at each coordinate is sequentially obtained based on the temperature change indicated by the thermoelectromotive force input from the lock-in amplifier 13 and stored, so that the thermal conductivity distribution of the sample 15 is measured.

Of course, since the surface shape and the heat conduction distribution of the sample 15 are measured at the same time, the computer 14 can perform an output in which the surface shape and the heat conduction distribution are superimposed on each other. Display output may be performed using graphics.

Next, referring to FIG.
Will be described. FIG. 5A is a perspective view of the cantilever 41, and FIG.
FIG. 7 is a sectional view taken along line BB of FIG. As shown in FIG. 5B, the cantilever 41 is composed of a beam 52 made of an elastic body,
2, first and second metal films 54 and 55 formed on outer surfaces facing each other with the beam 52 and the support 53 interposed therebetween, and the support 53 of the beam 52. The first and second metal films 54 project from the opposite end,
The probe 51 includes a probe 51 having a thermocouple 55 and a thin-film heating element 58 formed of metal.

The heating element 58 has a high resistance because the line width is small in the vicinity of the probe 51, and when the heating element 58 is energized by the heater power supply 42, the heating element 58 is heated by Joule heat. As a result, the nearby probe 51
Heat. The resistance of the heating element 58 can be changed by changing the line width or by changing the kind of metal such as chromel, alumel, nichrome or the like to change the volume resistivity and form a heating element having an arbitrary resistance. . Further, the resistance portion of the heating element 58 is meandered in the vicinity of the probe 51,
It is possible to efficiently perform AC heat generation on the probe 51 portion.

Since the first and second metal films 54 and 55 are materials forming a thermocouple, they need to be a combination of metals forming a thermocouple. For example, the first
By using chromel as the metal and alumel as the second metal, a chromel-alumel thermocouple can be formed. Of course, selection of a combination of metals constituting the thermocouple requires a suitable electromotive force at a temperature in the measurement range.

The beam 52 is made of silicon nitride, and the support 53 is made of silicon. The first metal film 54 forms a strip-shaped wiring pattern 54b from the probe 51 to the center of the upper surface of the support 53.
A square electrode pattern 54a is formed in the center of the upper surface of No. 3. Further, a film having a shape facing the first metal film 54 is also formed by the second metal film 55. On the other hand, the heating element 58
Also, a strip-shaped wiring pattern 56b is formed of the same metal as the first metal, and a square electrode pattern 56a is formed on the upper surface of the support 53.

Next, a method of manufacturing the cantilever 41 will be described with reference to FIG. The production of the cantilever 41 is obtained by adding a heating element 58 to the production of the cantilever 1.

FIGS. 6A to 6D are cross-sectional views showing the steps of manufacturing the cantilever 41. FIG. First, a diameter of 3 inches covered with a natural oxide film, a thickness of 250 μm, (10
0) Silicon nitride films 61a and 61b were formed on both surfaces of an n-type silicon substrate 60 with plane orientation by low pressure vapor phase epitaxy using dichlorocyan and ammonia gas as raw materials. Further, by partially patterning the silicon nitride film 61a on the substrate 60 by a photolithography method and a dry etching method, a square shape exposing the surface of the substrate 60 at a predetermined position of the silicon nitride film 61a on the upper surface of the substrate 60 is formed. Opening h2 is formed. One side of the removed square is 5 to 10 μm. Here, the opening h2
Are square, but these pattern shapes and sizes can be arbitrarily set. Thereafter, the substrate is immersed in a silicon etching solution such as an aqueous solution of potassium hydroxide (KOH) or an aqueous solution of tetramethylammonium hydroxide (TMAH) to form a silicon nitride film 61.
The substrate 60 exposed from the opening h using the masks a and 61b as masks.
Is anisotropically etched in the shape of a quadrangular pyramid to form a quadrangular pyramid-shaped trench hh2 continuous with the opening h2 of the silicon nitride film 61a.
Is formed (FIG. 6A). In addition, (1)
00) plane orientation is used, and as is well known, etching is performed on silicon (11
1) Since the surface automatically stops at the surface, the surface of the trench hh2 is a tapered surface having an angle of 54.7 degrees.

Thereafter, the substrate in the state shown in FIG. 6A is placed in an electric furnace and heated, and the trench h of the exposed substrate 30 is exposed.
A silicon oxide film 62 is grown on the portion h2 by thermal oxidation. As is well known, the growth rate of the silicon oxide film is fast at a flat portion and slow at a corner portion. Therefore, the cross-sectional shape of the silicon oxide film 62 grown in the trench hh2 is As shown in FIG. 6B, the thickness of the bottom portion is extremely thin as compared with other portions. Thereafter, the shape of the cantilever 41 is patterned on the surface of the substrate in this state, and the shape of the support 53 is patterned on the back surface of the substrate. On the surface of this substrate, gold,
Platinum, nichrome, chromel, alumel, platinum rhodium,
The first metal film 63 and the heating element 66 forming a thermocouple of nickel or the like are patterned (FIG. 6B).

Further, the substrate in the state shown in FIG.
The substrate is immersed in an aqueous solution of potassium hydroxide heated to 85 ° C. at a concentration of wt% to elute only unnecessary silicon portions, thereby forming a cantilever 41 in a cantilever state. The probe 41b
Is removed by etching to expose the first metal film 66 forming the probe 41b (FIG. 6C).

Thereafter, unlike the first metal film 63 previously formed on the back surface of the substrate, the second metal film 6 forming a thermocouple is formed.
4 is formed. As a result, a thermocouple having the probe 67 serving as a temperature measuring contact is formed in the distal end region 65 of the cantilever 41 (FIG. 6D). As a result, the tip of the probe 67 becomes sharp and has a very small radius of curvature, which makes it possible to measure the heat conduction distribution at the molecular and atomic levels.

The thinned cantilever manufactured in this manner has mechanical strength and can efficiently manufacture a large number of cantilevers having the same shape and the same quality. In addition, since the microfabrication is performed, the heat capacity of the probe portion forming the thermocouple becomes small, so that even if the voltage applied to the heating element 66 is modulated by a high frequency, it follows the high-frequency AC heating change. be able to.

In the above-described first embodiment, the laser power supply 11 modulates the laser light at a predetermined frequency. However, the present invention is not limited to this. Light may be mechanically modulated by a chopper or the like. Further, instead of modulating the laser power supply 11 itself with a predetermined frequency set in advance, the computer 14 may be able to change and set an arbitrary frequency as needed.

In each of the first and second embodiments described above, the cantilever 1 and 41 are fixed and the sample 1
The cantilever 1 and 41 are relatively scanned by moving the sample movable unit 3 side on which the sample moving unit 5 is installed. On the contrary, the sample movable unit 3 side is fixed and the cantilever 1 and 41 are fixed. The scanning may be directly performed on the lever supporting portion 6 supporting the 41 and the like.

Furthermore, in the above-described first and second embodiments, it is premised that constant AC heating is performed, and the heat conduction distribution is measured by detecting this temperature change. However, the present invention is not limited to this. Alternatively, the heat conduction distribution may be measured by changing the AC heating so as to detect a constant temperature, and measuring the amount of change.

[0059]

As described in detail above, the first aspect of the present invention has an advantage that the heat conduction distribution can be measured with high resolution and high accuracy while reducing the influence of the measurement environment change and the DC drift.

According to the second invention, as in the first invention, the influence of the change of the measurement environment and the DC drift can be reduced, and only the desired probe portion is locally and locally used because of the laser beam. This has the advantage that AC heating can be performed efficiently.

According to the third aspect of the invention, the laser light source for position detection and the laser light source for AC heating can be used in common, and there is an advantage that the entire apparatus is simplified.

The fourth aspect of the invention has an advantage that, similarly to the first aspect of the invention, it is possible to measure the heat conduction distribution with high accuracy while reducing the influence of the change of the measurement environment and the DC drift.

In the fifth aspect, since the temperature sensor is a thermocouple, there is an advantage that the temperature of the probe itself can be measured directly and in a wide range.

In the sixth aspect, since the cantilever including the tip portion is manufactured as a thin film element thinned by a semiconductor manufacturing technique, a large number of cantilevers having the same shape and the same performance are manufactured by using a semiconductor process. In addition to having the advantage of increasing production efficiency, it can produce a sharp probe shape uniformly and stably,
It has the advantage of enabling measurement with high resolution.

In the seventh aspect, the cantilever and the sample are relatively scanned by moving the sample support on which the sample is placed. Therefore, the cantilever side is fixed, and the cantilever is fixed to the cantilever side. The laser beam emitted from the laser light source is less likely to be displaced, and the scanning and measurement can be stably performed.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a scanning heat conduction distribution measuring device according to a first embodiment of the present invention.

FIG. 2 is a perspective view and a cross-sectional view taken along line AA of the cantilever 1 of the scanning heat conduction distribution measuring device shown in FIG.

FIG. 3 is a sectional explanatory view showing a manufacturing process of the cantilever 1 shown in FIG.

FIG. 4 is a block diagram showing a configuration of a scanning heat conduction distribution measuring device according to a second embodiment of the present invention.

5 is a perspective view of a cantilever 41 of the scanning thermal conductivity distribution measuring device shown in FIG. 4 and a cross-sectional view taken along line BB.

FIG. 6 is a sectional explanatory view showing a manufacturing process of the cantilever 41 shown in FIG.

[Explanation of symbols]

 1, 41 cantilever 2 lever holder 3 sample movable section 4 laser light source 5 position sensor 6 lever support section 7 sample support section 8 IV conversion 9 amplifier 10 thermoelectromotive force amplifier 11 laser power supply 12 drive device 13 lock-in amplifier 14 computer 15 Sample 42 heater power supply

Claims (7)

[Claims] 1. An elastically deformable cantilever having a probe at a tip and a temperature sensor thermally coupled to the probe, and the probe is brought into contact with the surface of the sample to relatively move the cantilever and the sample. A heating means for heating the probe while changing the heating amount periodically with time; and a temperature for detecting a periodically changing temperature change among the temperatures detected by the temperature sensor. A scanning type heat conduction distribution measuring device, comprising: a detecting unit. 2. The heating unit periodically irradiates a laser beam to the vicinity of the probe and changes the light intensity applied to the probe periodically with time, thereby periodically changing the heating amount of the probe. The scanning type thermal conductivity distribution measuring device according to claim 1, wherein 3. The apparatus according to claim 2, further comprising a position sensor configured to detect a deflection of the cantilever based on a reflection of the laser beam irradiated by the heating unit to detect the unevenness of the sample. Scanning heat conduction distribution measurement device. 4. The heating device according to claim 1, wherein the heating means includes a heating element provided on the cantilever, the heating amount being periodically changed by applying a periodically changed voltage. The scanning thermal conductivity distribution measuring device according to the above. 5. The scanning thermal conductivity distribution measuring device according to claim 1, wherein said temperature sensor is a thermocouple. 6. The scanning thermal conductivity distribution measurement according to claim 1, wherein the cantilever including the tip is a thin film element thinned by a semiconductor manufacturing technique. apparatus. 7. The scanning unit according to claim 1, wherein the scanning unit moves the sample support unit on which the sample is placed, thereby relatively scanning the cantilever and the sample.
The scanning thermal conductivity distribution measuring device according to any one of claims 6 to 13.