JP4751190B2 - Probe for temperature measurement - Google Patents

Description

  The present invention relates to a temperature measuring probe and a temperature measuring apparatus for measuring thermophysical properties in a minute region of a sample surface.

Currently, a scanning probe microscope (SPM: Scanning Probe Microscope) is used as a microscope for observing a nanometer-order minute region on the sample surface. Among these SPMs, an atomic force microscope (AFM) that uses a cantilever provided with a probe at the tip as a scanning probe has attracted particular attention. This atomic force microscope scans a cantilever probe along the sample surface, and detects the atomic force (attraction or repulsive force) generated between the sample surface and the probe as the amount of deflection of the cantilever. Surface shape measurement is performed. There are two types of cantilevers: optical lever type and self-detecting type because of the difference in the measurement method of the amount of deflection. In such a scanning probe microscope, in recent years, a method has been proposed for measuring the temperature distribution in a minute region of the sample surface as well as the uneven shape of the sample surface (see, for example, Patent Document 1 or 2).
JP-A-8-105801 JP 2001-4455 A

  However, in the probe of the above-mentioned patent document 1, a spindle-shaped groove is formed by etching the silicon substrate and the probe is formed along the shape of the groove. Due to restrictions in the manufacturing process, the shape of the probe is a cone with a large diameter at the root and a sharp tip. For this reason, there is a problem that it is difficult to form a probe having a high aspect ratio ((probe height) / (probe root diameter)).

  When using a probe with such a low aspect ratio, for example, when observing a surface shape having a substantially vertical surface, the side surface of the cone-shaped probe comes into contact with the substantially vertical surface, which is accurate. There was a problem that the surface shape and temperature distribution could not be observed.

  Further, in the probe of Patent Document 2, since a nickel fine wire is used as a cantilever and a probe, the diameter of the root portion of the probe becomes large, and it is difficult to obtain a probe with a high aspect ratio.

  The present invention has been made to solve the above-described problems, and is capable of observing the surface shape of a sample having irregularities with a high aspect ratio with high sensitivity and detecting the temperature characteristics of the sample. It is to provide a probe that is possible.

  In order to solve the above problems, the present invention proposes the following means.

  The probe of the present invention is provided on a cantilever having an insulating layer on the surface, a first metal structure having a first end at the tip of the cantilever, and provided on the top of the cantilever. A second metal structure having a second end provided on the upper surface of the end, a base formed on the upper surface of the second end and formed in a rod shape, and a sharpened tip A first metal structure that is provided at a distal end of the cantilever and connected to a first electrode that is provided at a proximal end of the cantilever, and a first metal structure A temperature measurement element comprising: a second metal structure connected to a second electrode provided on the upper surface of the cantilever and spaced apart from the first electrode at a proximal end portion of the cantilever; Provided on the upper surface of the element, and a base formed in a rod shape, and sharpened And the probe having a tip, was to have.

  According to the probe of the present invention, since the probe is disposed immediately above the temperature measuring element, it is possible to measure the surface shape of the sample and accurately measure the temperature characteristics of the sample. Further, since the shape is columnar from the base to the tip, it is possible to obtain a probe with a high aspect ratio, and therefore it is possible to accurately follow and measure irregularities with a high aspect ratio.

  In the above probe, the probe is preferably made of the same material as that of the second metal structure.

  According to the probe of the present invention, since the material composing the probe and the material composing the first metal structure are the same, the dissimilar material is joined at the connecting portion of the probe and the first metal structure. A stable measurement result can be obtained without causing a measurement error of the temperature characteristic due to the formation of.

  Further, the scanning probe microscope of the present invention includes a temperature characteristic measurement probe and probe displacement data that is displaced according to the sample surface shape by moving the probe close to the surface to be measured and scanning the sample surface. A displacement detecting means for detecting the probe, a moving means for scanning the probe in two directions parallel to the sample surface relative to the sample and perpendicular to each other, and moving in the vertical direction to the sample surface; And a thermoelectromotive force detector that detects thermoelectromotive force of the element.

  According to the scanning probe microscope of the present invention, a probe having a high aspect ratio and serving as both a temperature measuring element and a probe for measuring a sample surface shape is mounted. For this reason, it is possible to measure the shape, temperature distribution, and thermal characteristics of the sample surface microregion having irregularities with a high aspect ratio on the surface with high sensitivity.

  Further, the scanning probe microscope of the present invention includes an excitation unit that resonates or forcibly vibrates the probe at a vibration frequency, and the displacement detection unit is a vibration detection unit that detects a vibration state of the probe.

  According to the scanning probe microscope according to the present invention, when the surface shape of a sample is measured by vibrating a cantilever such as a DFM mode, the resonance frequency of the cantilever is increased, and the interaction with the sample can be measured with high sensitivity. it can.

  In the probe of the present invention, the displacement detection means is provided in the cantilever.

  Further, the displacement detecting means is a piezoresistive element.

  According to the probe of the present invention, since it is not necessary to provide the cantilever with a reflecting surface for reflecting the laser light, it is not necessary to be restricted by the shape of the cantilever, the degree of freedom in designing the probe is improved, and it is easy to manufacture. In addition, since a large-scale device such as a laser light source is unnecessary, the device cost and the device space can be reduced.

  The probe of the present invention includes a step of forming a cantilever by cutting a silicon substrate, a step of forming an insulating film on the upper surface of the cantilever, and a first metal structure on the upper surface of the insulating film on the tip end side of the cantilever. Forming a temperature measuring element by forming a first end of the body and forming a second end of the second metal structure on the upper surface of the first end; and a temperature measuring element Forming a probe by electroforming on the upper surface of the substrate, sharpening the tip of the probe by electrolytic polishing, cutting the silicon substrate, and forming a body on the base end side of the cantilever, It was decided to consist of

  According to the method for manufacturing a temperature measuring probe according to the present invention, a probe having a high aspect ratio, which has been difficult with the conventional manufacturing method, can be accurately and easily manufactured by forming the probe by electroforming. It becomes possible.

  Further, by sharpening using a technique such as electropolishing, it becomes possible to observe the temperature characteristics and irregularities of the micro-area of the sample surface with high resolution.

  According to the present invention, a sharpened probe having a high aspect ratio can be obtained. For this reason, it is possible to accurately measure the shape, temperature distribution, and thermal characteristics of the micro area on the sample surface having irregularities with a high aspect ratio.

  Embodiments of the present invention will be described below.

  1 to 12 show an embodiment according to the present invention. FIG. 1 shows a block diagram of a scanning probe microscope. 2 is a perspective view of the probe, FIG. 3 is a plan view, and FIG. 4 is a cross-sectional view. 5 to 12 show process diagrams of the probe manufacturing process.

  As shown in FIG. 1, a scanning probe microscope 1 includes a sample support unit 9 that supports a sample 100, a sample moving unit 3 that moves the sample 100, and a sample upper surface S of the sample 100 that is relatively moved by the sample moving unit 3. The probe 20 having the probe 21 to be scanned automatically and the vibration means 51 for vibrating the probe 21 of the probe 20 at a frequency at which the cantilever 22 resonates or forcibly vibrates. The probe 20 includes a cantilever 22 provided with a probe 21 protruding from a distal end portion, and a main body portion 23 that fixes a proximal end portion of the cantilever 22 in a cantilever state so that the distal end portion is a free end.

  The sample moving means 3 supports the sample supporting portion 9 and moves in the X and Y directions which are two directions parallel to the sample upper surface S and perpendicular to each other and the Z direction which is a direction perpendicular to the sample upper surface S. And a driving device 4 for driving the sample moving means 3. More specifically, the sample moving means 3 includes a coarse movement mechanism that coarsely moves the sample 100 in the X, Y, and Z directions, an XY scanner that finely moves the sample 100, and a Z scanner. An example of the driving device 4 corresponding to the coarse movement mechanism is a stepping motor. Further, the driving device 4 corresponding to the XY scanner and the Z scanner is a piezoelectric element made of, for example, PZT (lead zirconate titanate) or the like. It is possible to slightly move 100 in the XYZ directions. The vibration means 51 is connected to the probe 20 to vibrate the probe 20 so as to vibrate at a predetermined frequency and amplitude, and the excitation means 51 applies a voltage to the piezoelectric element to vibrate the piezoelectric element. A vibration power source 5 is provided.

  Further, as shown in FIG. 1, the scanning probe microscope 1 includes a displacement detection unit 6 that detects a vibration state of the probe 21 of the probe 20 vibrated by the vibration unit 51. The displacement detection means 6 includes a laser light source that irradiates laser light onto a reflective surface (for example, formed by coating a metal material such as gold or aluminum: not shown) formed on the back surface of the probe 21, and a power source for the laser light source And a photodiode for detecting the laser beam reflected by the reflecting surface. The laser beam detected by the photodiode is output as a DIF signal, amplified by a preamplifier, converted to DC by an AC-DC converter, and sent to the computer 7. The computer 7 is provided with a Z voltage feedback circuit, which applies a voltage to the Z scanner of the sample moving means 3 based on the DIF signal input to the computer 7 to move the sample 100 minutely in the Z direction.

  As shown in FIG. 1, the scanning probe microscope 1 includes a temperature characteristic detection unit 8 that is connected to the probe 20 and measures the thermoelectromotive force generated by the probe 21. Further, the computer 7 is connected to the driving device 4, the vibration power source 5, the displacement detecting means 6, and the temperature characteristic detecting unit 8 as described above.

  With the above configuration, the scanning probe microscope 1 measures the surface shape and temperature characteristics of the sample 100 as shown below. First, the excitation means 51 is vibrated by the excitation power source 5 under the control of the computer 7, and the laser beam is irradiated from the displacement detection means 6 to the reflection surface of the cantilever 22 of the probe 20. The cantilever 22 vibrates up and down by the vibration transmitted from the vibrating means 51, whereby the laser light reflected by the cantilever 22 and detected by the photodiode of the displacement detecting means 6 forms a vibration waveform having a constant amplitude and frequency. . In this state, the driving device 4 is driven under the control of the computer 7 to scan the sample 100 in the X and Y directions, and the surface shape and temperature characteristics of the sample 100 are measured. When the probe 21 of the probe 20 is scanned at the position where the probe 21 is uneven, the vibration amplitude of the laser light detected by the photodiode of the displacement detection means 6 is attenuated. This vibration amplitude is amplified by a preamplifier as a DIF signal, converted into a direct current by an AC-DC converter, and input to the computer 7. The computer 7 is provided with the aforementioned Z voltage feedback circuit. When the vibration amplitude converted into the DIF signal exceeds the threshold value, the drive device 4 is driven based on the input DIF signal, and the vibration amplitude is reduced. The sample moving means 3 is moved and adjusted in the Z direction so as to be constant within the threshold value. The surface shape of the sample 100 is measured by repeating this by moving the sample 100 in the X and Y directions by the driving device 4.

  Further, in parallel with the measurement of the surface shape of the sample 100, the thermoelectromotive force generated in the probe 21 is measured. The measurement results of the surface shape and temperature characteristics of the sample 100 are displayed by the computer 7 together with the scanning positions of the sample 100 in the X and Y directions.

Next, a detailed configuration of the probe 20 mounted on the scanning probe microscope 1 will be described.
FIG. 2 is an overall perspective view of the probe 20, but is described so as to be upside down with respect to the direction in which it is mounted on the scanning probe microscope 1.

  As shown in FIG. 2, the probe 20 includes a first metal structure 29 and a second metal structure 30, a probe 21 having a sharpened tip and a base formed in a rod shape, and a probe 21 includes a cantilever 22 provided so as to protrude from the distal end portion, and a main body portion 23 that fixes the base end portion of the cantilever 22 in a cantilever state so that the distal end portion is a free end. The cantilever 22 and the main body 23 include a silicon substrate, in particular, a silicon active layer 24 and a silicon support layer 25 made of silicon, and a BOX layer 26 made of SiO 2 interposed between the silicon active layer 24 and the silicon support layer 25. It is formed from a bonded SOI substrate 27 (Silicon on Insulator).

  Further, as shown in FIGS. 3 and 4 (cross section AA in FIG. 3), an insulating film 28 is formed on the surface of the cantilever 22, and the first metal is formed on the insulating film 28 from the distal end portion to the proximal end portion. A structure 29 and a second metal structure 30 are formed. The insulating film 28 is a silicon oxide film made of SiO2. The first metal structure 29 is a metal film made of chromium, and the second metal structure 30 is a metal film made of nickel. The first metal structure and the second metal structure are not limited to chromium and nickel, but may be any material that can form a thermocouple, such as gold, platinum, platinum rhodium, nichrome, chromel, and alumel. . The probe 21 is formed in such a manner that the tip of the surface of the cantilever 22, the first end 291 of the first metal structure 29, and the second end 301 of the second metal structure wiring 30 overlap. It protrudes on the connected part. The probe 21 is made of nickel and has conductivity. The material for forming the probe 21 is not limited to nickel, but may be any material that can be formed by an electroforming method to be described later, and may be gold, copper, rhodium, palladium, tungsten, or the like.

  In the probe 20 of this embodiment, since the probe 21 is directly formed on the second end portion 301 of the second metal structure 30 by electroforming, the temperature at the tip of the probe 21 is the first temperature. A temperature characteristic shown in FIG. 1 is transmitted to a connection portion formed in a form in which the first end portion 291 of the metal structure 29 and the second end portion 301 of the second metal structure 30 are overlapped with each other with little loss. The temperature characteristic of the sample 100 can be measured by the detection means 8. In addition, since the tip of the probe 21 is sharpened and the base is formed in a rod shape, the probe can have a high aspect ratio. For this reason, even if the sample 100 has a surface shape having unevenness with a high aspect ratio, the probe 21 accurately follows the unevenness, and the depth and width of the unevenness are measured with high accuracy and accurate observation is performed. An image can be obtained. Furthermore, it is possible to measure the temperature characteristics of the deeply uneven portion.

Next, a method for manufacturing the probe 20 of this embodiment will be described. As described above, the cantilever 22 and the main body 23 of the probe 20 are formed from the SOI substrate 27 including the silicon active layer 24, the BOX layer 26, and the silicon support layer 25. Here, the thickness of the silicon active layer 24 is set to the thickness of the cantilever 22, and the thicknesses of the BOX layer 26 and the silicon support layer 25 are set to the thickness of the main body portion 23. Hereinafter, it demonstrates in order.
As shown in FIGS. 5A to 5C, the cantilever 22 is formed in the cantilever forming step. First, as shown in FIG. 5A, a photoresist film 32 is formed in a range where the cantilever 22 is formed by photolithography. Then, as shown in FIG. 5B, by using the photoresist film 32 as a mask, the silicon active layer 24 is etched until it reaches the BOX layer 26, whereby the silicon active layer 24 around the portion that becomes the cantilever 22 is cut out. . Then, by removing the photoresist film 32, the cantilever 22 is formed as shown in FIG. The photoresist film may be a positive type or a negative type. As a method for etching the cantilever 22, either dry etching or wet etching may be used, but dry etching is preferable. Examples of dry etching include reactive ion etching (RIE) and DRIE (Deep Reactive Ion Etching). In the case of wet etching, there is anisotropic etching using an alkaline etchant such as potassium hydroxide (KOH) or tetramethylammonium hydroxide (TMAH).

  Next, as shown in FIG. 6A, an insulating film 28 is formed on the surface of the cantilever 22 in the insulating film forming step. The insulating film 28 is formed by a thermal oxidation method. At this time, the oxide film 33 is also formed on the back surface side of the cantilever 22, that is, on the surface of the silicon support layer 25 on the portion that becomes the main body portion 23. That is, as shown in FIG. 6A, the oxide film 33 is formed simultaneously with the formation of the insulating film 28 on the entire surface of the silicon support layer 25. Next, as shown in FIG. 6B, the back surface of the main body 23 and the entire side where the cantilever 22 is formed are patterned with a photoresist film 34. Then, as shown in FIG. 6C, the oxide film 33 other than the portion where the photoresist film 34 is patterned is removed by hydrofluoric acid, and finally, as shown in FIG. Remove.

  Next, as shown in FIGS. 7A to 7C, the first metal structure 29 and the second metal structure wiring 30 are formed on the insulating film 28 in the temperature measurement element forming step. To do. First, as shown in FIG. 7A, a portion other than the portion that becomes the first metal structure 29 is patterned with a photoresist film 35. Next, as shown in FIG. 7B, a chromium film is formed on the entire surface by sputtering. Then, as shown in FIG. 7C, the first metal structure 29 is formed by removing the photoresist film 35.

  In addition, the method of forming the chromium film used as the first metal structure 29 is not limited to the sputtering method, and may be an evaporation method. In addition, a chromium film is formed on the entire surface by sputtering or vapor deposition in advance, and a photoresist film is patterned on a portion that becomes the first metal structure 29. Subsequently, the first metal structure 29 may be formed by removing a portion of the chromium film where the photoresist film is not formed by etching.

  Next, the second metal structure 30 is formed in the same manner as the method of forming the first metal structure 29. As shown in FIGS. 8A to 8C, a portion other than the portion that becomes the second metal structure 30 is patterned with the photoresist film 36. Next, as shown in FIG. 8B, a nickel film is formed on the entire surface by sputtering. Then, as shown in FIG. 8C, the second metal structure 30 is formed by removing the photoresist film 36. Note that the method for forming the nickel film to be the first metal structure 30 is not limited to the sputtering method, and may be a vapor deposition method.

  Next, in the probe forming step, the probe is formed on the connection portion formed by overlapping the first end 291 of the first metal structure 29 and the second end 301 of the second metal structure wiring 30. The needle 21 is formed. The probe forming process includes two processes, a base forming process and a tip sharpening process. FIGS. 9A to 9C show the base forming process. First, as shown in FIG. 9A, a photoresist film 37 having a thickness substantially equal to the height of the probe 21 is formed on the entire cantilever 22 side. As the photoresist film 37, there are a positive resist and a negative resist, but a negative resist in which a pattern of a portion irradiated with ultraviolet rays, an electron beam, a laser or the like is suitable is suitable. For example, SU-8 (Kayaku Microchem Corporation Company SU-8 series). Then, masking is performed at the position of the probe 21 so as to be equal to the cross-sectional shape of the base. Here, since the cross-sectional shape of the base is circular, masking is circular. Then, as shown in FIG. 9B, the photoresist film 37 is exposed and a developing solution is dropped to melt the unexposed range. Next, as shown in FIG. 9 (c), the second metal structure 30 is infiltrated into the electrolytic solution as one electrode, and nickel is electroformed into the hollow portion by electroforming, so that the probe 21 is formed. And a base including a polishing margin is formed.

  Next, as shown in FIG. 10A, the tip of the probe 21 exposed from the photoresist film 37 is polished by electropolishing to sharpen the polishing margin. Finally, as shown in FIG. 10B, if the photoresist film 37 is removed, the tip 21 is sharpened and the probe 21 having a base-like base is formed.

  Next, as shown in FIGS. 11A to 11C, the main body portion 23 is formed in the main body portion forming step. First, as shown in FIG. 11A, in order to protect the cantilever 22 on which the probe 21, the first metal structure 29, and the second metal structure wiring 30 are disposed, the entire surface on the cantilever 22 side is protected. A photoresist film 38 is formed. Next, as shown in FIG. 11B, the silicon support layer 25 other than the main body 23 is etched using the oxide film 33 formed in the insulating film formation step as a mask. In this case, either dry etching or wet etching may be used, but wet etching is preferable. Then, as shown in FIG. 11C, the oxide film 33 and the BOX layer 26 other than the main body 23 are removed by hydrofluoric acid, and the photoresist film 38 is removed, thereby removing the probe 20 shown in FIG. Is produced.

  13 to 24 show an embodiment according to the present invention. FIG. 13 shows a block diagram of a scanning probe microscope. FIG. 14 is a perspective view of the probe, and FIGS. 15 to 23 are process diagrams of the probe manufacturing process. FIG. 24 shows an example in which a slit is formed at the base of the cantilever of this embodiment. In this embodiment, the same members as those used in the above-described embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  As shown in FIG. 13, the scanning probe microscope 2 according to the present embodiment includes a sample support unit 9 that supports the sample 100, a sample moving unit 3 that moves the sample 100, and a sample of the sample 100 by the sample moving unit 3. A probe 201 having a probe 21 that is relatively scanned on the upper surface S is provided, and an excitation means 51 that vibrates the probe 21 of the probe 201 at a frequency at which the cantilever 22 resonates or is forcedly oscillated. The probe 201 includes a cantilever 22 provided with a probe 21 protruding from a distal end portion, and a main body portion 23 that fixes the proximal end portion of the cantilever 22 in a cantilever state so that the distal end portion is a free end.

  The sample moving means 3 supports the sample supporting portion 9 and moves in the X and Y directions which are two directions parallel to the sample upper surface S and perpendicular to each other and the Z direction which is a direction perpendicular to the sample upper surface S. And a driving device 4 for driving the sample moving means 3. More specifically, the sample moving means 3 includes a coarse movement mechanism that coarsely moves the sample 100 in the X, Y, and Z directions, an XY scanner that finely moves the sample 100, and a Z scanner. An example of the driving device 4 corresponding to the coarse movement mechanism is a stepping motor. Further, the driving device 4 corresponding to the XY scanner and the Z scanner is a piezoelectric element made of, for example, PZT (lead zirconate titanate) or the like. It is possible to slightly move 100 in the XYZ directions. The vibration means 51 is connected to the probe 201 to vibrate the probe 201 so as to vibrate at a predetermined frequency and amplitude, and the excitation means 51 applies a voltage to the piezoelectric element to vibrate the piezoelectric element. A vibration power source 5 is provided.

  Further, the displacement detecting means 60 for measuring the displacement of the probe 21 measures the displacement of the probe based on the resistance change detected by the piezoresistive element provided at the base end portion of the cantilever 22 and detecting the deflection of the cantilever. did.

  FIG. 14 is an overall plan view of the probe 201, which is shown upside down with respect to the direction in which it is mounted on the scanning probe microscope 2. FIG.

  As shown in FIG. 14, the probe 201 includes a first metal structure 29 and a second metal structure 30, a probe 21 with a sharpened tip and a base formed in a rod shape, and a probe 21 includes a cantilever 22 provided so as to protrude from the distal end portion, and a main body portion 23 that fixes the base end portion of the cantilever 22 in a cantilever state so that the distal end portion is a free end. A piezoresistive element 40 for detecting the bending of the cantilever 22 is formed at the base end portion of the cantilever 22, and a piezoresistive element electrode wiring 41 for detecting a change in resistance of the piezoresistive element 40 is formed on the main body portion 23 of the cantilever 22. And 42 are formed. The cantilever 22 and the main body 23 include a silicon substrate, in particular, a silicon active layer 24 and a silicon support layer 25 made of silicon, and a BOX layer 26 made of SiO 2 interposed between the silicon active layer 24 and the silicon support layer 25. It is formed from a bonded SOI substrate 27 (Silicon on Insulator).

  Next, a method for manufacturing the probe 201 of this embodiment will be described. 16 and 18 are cross-sectional views taken along the line BB ′ of FIG. 14, and FIGS. 15, 17, and 19 to 23 are cross-sectional views taken along the line AA ′ of FIG.

  As described above, the cantilever 22 and the main body 23 of the probe 201 are formed from the SOI substrate 27 including the silicon active layer 24, the BOX layer 26, and the silicon support layer 25. Here, the thickness of the silicon active layer 24 is set to the thickness of the cantilever 22, and the thicknesses of the BOX layer 26 and the silicon support layer 25 are set to the thickness of the main body portion 23. Hereinafter, it demonstrates in order.

  As shown in FIGS. 15A to 15C, the cantilever 22 is formed in the cantilever forming step. First, as shown in FIG. 15A, a photoresist film 32 is formed in a range where the cantilever 22 is formed by a photolithography technique. Then, as shown in FIG. 15B, by using the photoresist film 32 as a mask, the silicon active layer 24 is etched until it reaches the BOX layer 26, so that the silicon active layer 24 around the portion that becomes the cantilever 22 is cut out. . Then, by removing the photoresist film 32, the cantilever 22 is formed as shown in FIG. The photoresist film may be a positive type or a negative type. As a method for etching the cantilever 22, either dry etching or wet etching may be used, but dry etching is preferable. Examples of dry etching include reactive ion etching (RIE) and DRIE (Deep Reactive Ion Etching). In the case of wet etching, there is anisotropic etching using an alkaline etchant such as potassium hydroxide (KOH) or tetramethylammonium hydroxide (TMAH).

  Next, as shown in FIG. 16, the piezoresistive element 40 is formed at the base end portion of the cantilever 22 in the piezoresistive element forming step. First, as shown in FIG. 16A, the entire side where the cantilever 22 is formed is patterned with a photoresist film 50. Next, as shown in FIG. 16B, the photoresist film 50 in a range where the piezoresistive element 40 is formed is removed by a photolithography technique. Then, as shown in FIG. 16C, by using the photoresist film 50 as a mask, boron is ion-implanted into the silicon active layer 24 to remove the photoresist film 50, so that the cantilever is shown in FIG. A piezoresistive element 40 is formed at the base end portion of 22. The photoresist film may be a positive type or a negative type.

  Next, as shown in FIG. 17A, an insulating film 28 is formed on the surface of the cantilever 22 in the insulating film forming step. The insulating film 28 is formed by a thermal oxidation method. At this time, the oxide film 33 is also formed on the back surface side of the cantilever 22, that is, on the surface of the silicon support layer 25 on the portion that becomes the main body portion 23. That is, as shown in FIG. 17A, the oxide film 33 is formed simultaneously with the formation of the insulating film 28 on the entire surface of the silicon support layer 25. Next, as shown in FIG. The back surface of the main body 23 and the entire side where the cantilever 22 is formed are patterned with a photoresist film 51. Then, as shown in FIG. 17C, the oxide film 33 other than the portion where the photoresist film 51 is patterned is removed by hydrofluoric acid, and finally, as shown in FIG. Remove.

  Next, as shown in FIGS. 18A to 18D, electrode wiring is formed on the piezoresistive element 40. First, as shown in FIG. 18A, the photoresist film 52 is used to pattern a portion other than the connection portion between the piezoresistive element 40 and the piezoresistive element electrode wires 41 and 42. Next, the portion of the insulating film 28 not protected by the resist is removed with hydrofluoric acid, and the resist 52 is further removed. Next, as shown in FIG. 18B, an aluminum film as an electrode wiring material is formed by sputtering on the entire surface of the cantilever 22 on which the piezoresistive element is formed, and as shown in FIG. 18C, the piezoresistive element is formed. A photoresist film 53 is formed on the portions to be the electrode wirings 41 and 42. As shown in FIG. 18D, the part of the aluminum film where the photoresist 53 is not formed is removed, and the photoresist film 53 is removed, thereby forming the piezoresistive element electrode wires 41 and 42.

  The method of forming the piezoresistive element electrode wires 41 and 42 is not limited to the sputtering method, and may be a vapor deposition method. Further, a photoresist film 53 is formed in advance on the entire surface, and a portion of the photoresist film 53 where the piezoresistive element electrode wires 41 and 42 are to be formed is removed. Subsequently, an aluminum film may be formed by a sputtering method or a vapor deposition method, and then the photoresist film 53 may be removed to form the piezoresistive element electrode wirings 41 and 42.

  Next, as shown in FIGS. 19A to 19C, the first metal structure 29 and the second metal structure wiring 30 are formed on the insulating film 28 in the temperature measurement element formation step. To do. First, as shown in FIG. 19A, a portion other than the portion that becomes the first metal structure 29 is patterned with a photoresist film 54. Next, as shown in FIG. 19B, a chromium film is formed on the entire surface by sputtering. Then, as shown in FIG. 19C, the first metal structure 29 is formed by removing the photoresist film 54.

  In addition, the method of forming the chromium film used as the first metal structure 29 is not limited to the sputtering method, and may be an evaporation method. In addition, a chromium film is formed on the entire surface by sputtering or vapor deposition in advance, and a photoresist film is patterned on a portion that becomes the first metal structure 29. Subsequently, the first metal structure 29 may be formed by removing a portion of the chromium film where the photoresist film 54 is not formed by etching.

  Next, the second metal structure 30 is formed in the same manner as the method of forming the first metal structure 29. As shown in FIGS. 20A to 20C, a portion other than the portion that becomes the second metal structure 30 is patterned with a photoresist film 55. Next, as shown in FIG. 20B, a nickel film is formed on the entire surface by sputtering. Then, as shown in FIG. 20C, the second metal structure 30 is formed by removing the photoresist film 55. Note that the method for forming the nickel film to be the first metal structure 30 is not limited to the sputtering method, and may be a vapor deposition method.

  Next, in the probe forming step, the probe is formed on the connection portion formed by overlapping the first end 291 of the first metal structure 29 and the second end 301 of the second metal structure wiring 30. The needle 21 is formed. The probe forming process includes two processes, a base forming process and a tip sharpening process. FIGS. 21A to 21C show the base forming process. First, as shown in FIG. 21A, a photoresist film 56 having a thickness substantially equal to the height of the probe 21 is formed on the entire cantilever 22 side. As the photoresist film 56, there are a positive resist and a negative resist, but a negative resist in which a pattern of a portion irradiated with ultraviolet rays, an electron beam, a laser, or the like is preferable. For example, SU-8 (Kayaku Microchem Corporation) Company SU-8 series). Then, masking is performed at the position of the probe 21 so as to be equal to the cross-sectional shape of the base. Here, since the cross-sectional shape of the base is circular, masking is circular. Then, as shown in FIG. 21B, the photoresist film 56 is exposed and a developing solution is dropped to melt the unexposed range. Next, as shown in FIG. 21 (c), the second metal structure 30 is infiltrated into the electrolytic solution as one electrode, and nickel is electroformed into the hollow portion by an electroforming method. And a base including a polishing margin is formed.

  Next, as shown in FIG. 22A, the tip of the probe 21 exposed from the photoresist film 56 is polished by electropolishing to sharpen the polishing margin. Finally, as shown in FIG. 22B, if the photoresist film 56 is removed, the probe 21 having a sharp tip and a rod-like base is formed.

  Next, as shown in FIGS. 23A to 23C, the main body portion 23 is formed in the main body portion forming step. First, as shown in FIG. 23A, in order to protect the cantilever 22 on which the probe 21, the first metal structure 29, and the second metal structure wiring 30 are disposed, the entire surface on the cantilever 22 side is protected. A photoresist film 57 is formed. Next, as shown in FIG. 23B, the silicon support layer 25 other than the main body 23 is etched using the oxide film 33 formed in the insulating film formation step as a mask. In this case, either dry etching or wet etching may be used, but wet etching is preferable. Then, as shown in FIG. 23 (c), the oxide film 33 and the BOX layer 26 other than the main body 23 are removed by hydrofluoric acid, and the photoresist film 57 is removed, whereby the probe 201 is manufactured. .

  In any of the embodiments described above, the cantilever 22 and the probe 21 are completely formed by forming the cantilever 22 in the above-described cantilever forming process and the probe 21 in the above-described probe forming process. A separate process can be performed. For this reason, the cantilever 22 can be formed from the SOI substrate 27, and the probe 21 can be formed from nickel by electroforming. Further, since the temperature measuring element forming step can be performed in a state where the probe 21 is not formed prior to the probe forming step, the first metal structure 29 and the second metal structure wiring 30 are connected to each other. It can be formed easily. In each of the above-described steps, patterning is performed by exposing the photoresist film. However, the present invention is not limited to this, and a direct drawing method using an electron beam or the like may be used.

  Furthermore, as shown in FIG. 24, a slit 24S may be formed at the base end of the cantilever 22. As a result, the base end portion of the cantilever 22 has a structure that is easy to bend, thereby enabling measurement with higher accuracy.

As mentioned above, although embodiment of this invention was explained in full detail with reference to drawings, the concrete structure is not restricted to this embodiment, The design change etc. of the range which does not deviate from the summary of this invention are included.
Although the cantilever and the main body of the probe are formed from an SOI substrate, the present invention is not limited to this, and a resin, semiconductor, glass, or metal coated with an insulating film may be used. In the probe manufacturing process, the probe forming process is divided into two processes of sharpening the tip and forming the base, but the present invention is not limited to this. It is also possible to change the cross-sectional shape of the base by further dividing the base into a plurality of steps.

Moreover, although it was set as the scanning probe microscope of the DFM mode which gives a vibration to a probe and measures the surface shape of a sample, it is not restricted to this, As what is used for the AFM mode which measures the displacement of a probe directly, Unevenness with a high aspect ratio can be measured with high sensitivity.
The probe is provided with a single probe. However, the present invention is not limited to this, and a plurality of probes may be provided so as to project as an array. Further, the probe is not limited to that provided in the scanning probe microscope.

1 is a block diagram of a scanning probe microscope according to a first embodiment of the present invention. It is a perspective view of the probe of a 1st embodiment of this invention. It is a top view of the probe of a 1st embodiment of this invention. It is sectional drawing of the probe of 1st Embodiment of this invention. It is process drawing which shows the cantilever formation process of the probe of 1st Embodiment of this invention. It is process drawing which shows the insulating film formation process of the probe of 1st Embodiment of this invention. It is process drawing which shows the formation process of the element for temperature measurement of the probe of 1st Embodiment of this invention. It is process drawing which shows the formation process of the element for temperature measurement of the probe of 1st Embodiment of this invention. It is process drawing which shows the probe formation process (base part) of the probe of 1st Embodiment of this invention. It is process drawing which shows the probe sharpening process of the probe of 1st Embodiment of this invention. It is process drawing which shows the main-body part formation process of the probe of 1st Embodiment of this invention. It is process drawing which shows the main-body part formation process of the probe of 1st Embodiment of this invention. It is a block diagram of the scanning probe microscope of the 2nd Embodiment of this invention. It is a top view of the probe of a 2nd embodiment of this invention. It is process drawing which shows the cantilever formation process of the probe of 2nd Embodiment of this invention. It is process drawing which shows the piezoresistive element formation process of the probe of 2nd Embodiment of this invention. It is process drawing which shows the insulating film formation process of the probe of 2nd Embodiment of this invention. It is process drawing which shows the electrode wiring formation process for piezoresistive elements of the probe of 2nd Embodiment of this invention. It is process drawing which shows the formation process of the element for temperature measurement of the probe of 2nd Embodiment of this invention. It is process drawing which shows the formation process of the element for temperature measurement of the probe of 2nd Embodiment of this invention. It is process drawing which shows the probe formation process (base part) of the probe of 2nd Embodiment of this invention. It is process drawing which shows the probe sharpening process of the probe of 2nd Embodiment of this invention. It is process drawing which shows the main-body part formation process of the probe of 2nd Embodiment of this invention. It is a top view of the probe of a 2nd embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 2 Scanning probe microscope 3 Sample moving means 4 Drive apparatus 51 Excitation means 5 Excitation power supply 6, 60 Displacement detection element 7 Computer 8 Temperature characteristic detection means 9 Sample support part 20, 201 Probe 21 Probe 22 Cantilever 23 Main body Part 24 silicon active layer 25 silicon support layer 26 BOX layer 27 SOI substrate (silicon substrate)
28 Insulating film 29 First metal structure 291 First end 30 Second metal structure 301 Second end 33 Oxide films 32, 34, 35, 36, 37, 38, 50
51, 52, 53, 54, 55, 56, 57 Photoresist film 40 Piezoresistive element 41, 42 Electrode wiring for piezoresistive element 100 Sample

Claims (4)

A cantilever having a free end on the tip side ;
An insulating film formed on one surface of the cantilever;
A main body fixed on a surface opposite to one surface of the base end of the cantilever;
A first metal structure formed on the insulating film and having a first end at a portion formed on a tip of the cantilever on the insulating film;
A second metal structure formed on the insulating film and having a second end formed on a surface opposite to the surface of the first end contacting the insulating film ;
Formed of the same material as the second metal structure, formed by electroforming on a surface of the second end opposite to the surface in contact with the first end, and one of the cantilevers A probe having a rod-shaped base formed perpendicular to the surface, and a sharpened cone-shaped tip formed on the base;
A temperature measurement probe comprising: The temperature characteristic measuring probe according to claim 1 ,
Displacement detecting means for detecting displacement data of the probe that is displaced according to a sample surface shape by causing the probe to approach the surface to be measured of the sample and scanning the sample surface;
Sample moving means for performing scanning in two directions perpendicular to each other and perpendicular to the surface of the sample, the probe being relatively parallel to the sample surface relative to the sample;
Temperature characteristic detecting means for detecting the thermoelectromotive force of the temperature measuring element;
A scanning probe microscope. Comprising vibration means for resonating or forcibly vibrating the probe at a vibration frequency;
The scanning probe microscope according to claim 2 , wherein the displacement detection unit is a vibration detection unit that detects a vibration state of the probe. 3. The scanning probe microscope according to claim 2 , wherein the displacement detection means is a piezoresistive element provided in a cantilever .

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