JP2009128139A - Scanning probe microscope and probe unit for scanning probe microscope - Google Patents

Abstract

[PROBLEMS] To detect a contact state between a probe and a sample and to vibrate the probe optically while driving a probe of a scanning probe microscope at extremely high speed, and to provide a large semiconductor substrate and a flat display substrate. Thus, it is possible to detect a high-speed scanning probe corresponding to a sample that cannot be driven on the sample side.
A light beam for optically detecting the contact state of the probe and the sample and oscillating the probe is introduced under the objective lens for observing the sample in a parallel beam state. By focusing and irradiating a certain point on the cantilever with a small condensing lens attached to be driven with the cantilever under the lens, it always irradiates a certain position on the cantilever even if it moves. In addition, since the condensing lens is very small, it is possible to observe and measure the sample by scanning the cantilever at high speed without affecting the dynamic characteristics of the cantilever driving unit.
[Selection] Figure 1

Description

  The present invention relates to a scanning probe microscope and a probe unit for a scanning probe microscope.

  A scanning probe microscope (SPM) is known as a technique for measuring a fine three-dimensional shape. This is a technique that scans a sample while controlling the cantilever with a pointed tip attached while keeping the contact force at a very small value, and is widely used as a technique that can measure the fine three-dimensional shape of atomic orders. ing.

  On the other hand, currently, in the fine pattern formation process of LSI, CD-SEM (length measurement SEM) is used for dimension management. However, since the process margin decreases with the miniaturization of the pattern, only the planar dimension is obtained. Instead, the need to manage the process by accurately measuring the three-dimensional shape of the pattern is increasing.

  For this reason, scanning probe microscope technology seems promising. In this case, since it is necessary to measure a large-diameter semiconductor wafer, the method of scanning the sample side used in a normal scanning probe microscope makes the sample heavy and difficult to measure at high speed. Therefore, a technique for performing measurement by scanning the probe side, not the sample side, at high speed is desired.

On the other hand, in Patent Document 1, the beam is always scanned at a predetermined position on the cantilever while scanning the cantilever while irradiating the light beam for detecting and exciting the cantilever through the probe and the objective lens for observing the sample. In order to irradiate, the method of driving the objective lens integrally with the probe operating mechanism has been shown.
JP 2006-329973 A

  However, even if the above-described method is used, it is difficult to obtain a sufficient speed because an objective lens having a large mass must be driven at a high speed.

The scanning probe microscope of the present invention comprises a drive mechanism that controls the mutual positional relationship between a sample stage on which a sample is placed and a cantilever equipped with a probe, and a sensor that optically measures the deformation state of the cantilever, A scanning probe microscope for measuring a surface distribution of the sample including a three-dimensional surface shape of the sample, the sensor comprising an optical microscope for observing the cantilever and the sample, and a sensor component for optically measuring the deformation state of the cantilever At least one optical element is disposed between the optical microscope and the sample, and is driven integrally with the driving mechanism.
The probe unit for a scanning probe microscope according to the present invention is characterized in that the condenser lens is integrated with a cantilever provided with a probe, and is aligned so that the cantilever comes to the focal position of the condenser lens. And

  According to the present invention, by providing a small and low-mass optical system for irradiating a predetermined position of the cantilever with a light beam that constantly detects and vibrates the cantilever while scanning the cantilever, There is an effect that the scanning can be performed at a high speed and the detection / vibration of the cantilever by light is compatible, and the scanning / measurement speed by the scanning probe microscope can be improved.

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

  FIG. 1 is a diagram showing the configuration of a scanning probe microscope according to the present invention. A sample 501 is placed on a sample stage 302 that can be driven in the X, Y, and Z directions, and is controlled by the scanning control unit 201. A cantilever moving mechanism 252 to which a cantilever 103 having a probe tip is attached is driven in the X, Y, and Z directions by a signal from the XYZ scanning driving unit 203, thereby performing probe scanning of the scanning probe microscope.

  By a signal from the cantilever driving unit 202, minute vibration can be generated in the cantilever 103 itself or an actuator composed of a piezoelectric element or the like disposed at the base of the cantilever. Alternatively, as another embodiment, the signal from the cantilever driving unit 202 is superimposed on the signal from the XYZ scanning driving unit 203 to excite the vibration to the cantilever 103 attached by causing a minute vibration in the cantilever moving mechanism. Also good. Alternatively, as described later, minute vibrations may be excited on the cantilever 103 by directly irradiating the cantilever with vibration excitation light. Although the minute vibration is used to detect the contact state between the probe 104 and the sample 501, the contact state is detected using static deformation of the cantilever 103 caused by the contact with the sample 501 without using the minute vibration. May be.

  Reference numeral 101 denotes a cantilever / sample observation lens. The sample 501 and the cantilever 103 are observed from above and the height of the sample is measured through this lens. The approach between the probe 104 and the sample 501 may be performed by driving control of the sample stage 302 in the Z direction or a Z-direction coarse movement function provided to the cantilever moving mechanism 252. The scanning control unit 201 controls the approach between the probe 104 and the sample 501 using the contact state between the probe 104 and the sample 501 detected by the contact state detector 205.

  The proximity sensor 204 is a sensor for measuring the height of the vicinity of the tip of the cantilever 103 with high sensitivity. When this sensor is used in addition to information from the contact state detector, the probe contacts the sample in advance. By detecting the position and controlling the approach speed, high-speed approach to the sample can be realized without hitting the probe against the sample. Light may be used for the proximity sensor 204 as will be described later, but other sensors may be used as long as the detection range is several tens of micrometers or more and the distance from the sample can be detected with a sensitivity of about 1 micrometer. May be.

  For example, a capacitive sensor that measures the capacitance by applying an AC voltage between a sensor head or probe 104 provided directly above the sample 501 (not shown) or the probe 501 and the sample 501 to detect the distance, or not shown An air microsensor that detects the pressure by flowing air from the sensor head between the sensor head provided immediately above the sample 501 and the sample 501 may be used.

  The scanning control unit 201 controls the probe contact state detector 205, the proximity sensor 204, the cantilever holder driving unit 203 having the probe formed at the tip, the cantilever driving unit 202, and the sample stage 302 to control the proximity of the probe and the sample. Realize scanning and so on. At this time, the surface shape image of the sample is obtained by sending a signal at the time of scanning the sample to the SPM image forming apparatus 208. The signal applying device 207 oscillates the cantilever at a high frequency and detects the response by the contact state detector 205 to measure the elasticity of the surface, or applies an AC or DC voltage between the cantilever and the sample to apply a current. Measure and measure capacitance or resistance.

  By performing this simultaneously with the cantilever scanning, it is possible to obtain an additional property distribution image in addition to the surface shape image in the SPM image forming apparatus 207. The overall operation of the apparatus is controlled by the overall control apparatus 250, and the display / input apparatus 251 can receive an instruction from the operator and can present an optical image or an SPM image.

  Hereinafter, the detection principle of the contact state of the probe 104 will be described with reference to FIG. The cantilever 103 formed with the probe 104 at the tip is attached to the cantilever moving mechanism 252. When the cantilever 103 is pushed down by the cantilever moving mechanism 252 and the probe 104 comes into contact with the sample 501, the cantilever 103 is bent and the angle changes. The cantilever 103 is irradiated with laser light, and the spot position of the reflected light is detected by the position sensor 116. Then, when the spot moves in the vertical direction in FIG. 2, it indicates that the cantilever 103 is deflected. From this, the vertical force Fz applied to the probe 104 can be measured. 2 indicates that the cantilever 103 is twisted, and the depth direction force Fy applied to the probe 104 can be measured. If the low-frequency component of the signal from the position sensor 116 is detected, static torsion and deflection of the cantilever can be detected, and if the high-frequency component is detected, the amplitude, phase, and frequency of the cantilever torsion and deflection vibration can be detected. Any information on static torsion and deflection, amplitude, phase and frequency of vibration can be detected and represents the contact state such as the contact force between the probe 103 and the sample 501 and the gradient of the contact force. The contact state detector 205 can detect the contact state.

のような関係がある。図３（ｂ）のように、上向の力Ｆｚだけがかかるときはカンチレバー１０３の中心部でも先端部に近い傾きを生じる。対して図３（ｃ）のように横向きの力Ｆｘのみがかかるときは、カンチレバー１０３の中心部の傾きは先端部の半分の傾きとなる。一つの実施例として、カンチレバー１０３に複数の光を当てて、複数の点の傾きを測ると探針１０４にかかる２方向の力、ＦｘとＦｚを分離して検出できる。たとえば、カンチレバー１０３の先端（ｘ＝Ｌ）と、中点（ｘ＝Ｌ／２）に光を当てると、それぞれ照射位置でのカンチレバ１０３の傾きは、

となり、ポジションセンサ１１６の出力もこれに比例する。これらの式をＦｘ、Ｆｚに関して解くと、下記のように２種類のポジションセンサ１１６の出力から探針１０４にかかる２方向の力、ＦｘとＦｚが下記のように算出できる。

Here, the detection of deflection will be described in detail. As shown in FIG. 3, there are two types of forces that cause the cantilever 103 to bend, a vertical force Fz applied to the probe and a horizontal force Fx applied to the probe. The Young's modulus of the cantilever is E, the length is L, the width is w, the thickness is d, and the height of the probe is ht. When the inclination at the distance x from the root on the cantilever 103 is θ (x),

There is a relationship like As shown in FIG. 3B, when only the upward force Fz is applied, the center portion of the cantilever 103 is inclined close to the tip portion. On the other hand, when only the lateral force Fx is applied as shown in FIG. 3C, the inclination of the center portion of the cantilever 103 is half the inclination of the tip portion. As one embodiment, by applying a plurality of lights to the cantilever 103 and measuring the inclinations of the plurality of points, the two-direction forces Fx and Fz applied to the probe 104 can be detected separately. For example, when light is applied to the tip (x = L) and the middle point (x = L / 2) of the cantilever 103, the inclination of the cantilever 103 at the irradiation position is

Thus, the output of the position sensor 116 is also proportional to this. When these equations are solved with respect to Fx and Fz, the two-direction forces Fx and Fz applied to the probe 104 can be calculated from the outputs of the two types of position sensors 116 as follows.

  As described above, by irradiating the cantilever 103 with two light beams and detecting the reflection direction, the forces in the three directions applied to the probe can be separated and detected. The two irradiation positions are not limited to the above example, and it goes without saying that separation of force can be similarly detected by irradiating two points that are separated to some extent.

  Next, another embodiment for detecting the inclination of the cantilever 103 will be described with reference to FIG. As shown in the figure, the tip end of the cantilever 103 can be detected by irradiating the tip with a laser beam 130 and detecting an interference signal with reference light. The reference light may be synthesized inside the detection unit as will be described later, or may be irradiated to the base of the cantilever 103 as indicated by 130 'in FIG. FIG. 4B is a view of the cantilever 103 as viewed from above. In order to detect not only the bending of the cantilever 103 but also the torsion at the same time, the detection laser 130 is irradiated to two locations a and b, respectively, the displacements Za and Zb are measured, and the bending is calculated from (Za + Zb) / 2. Torsion can be detected from (Za-Zb). In the case of irradiating the reference beam 130 ′, it is sufficient to irradiate the position c in FIG. As another example, when detecting the vibration state of the cantilever 103, the detection laser 130 is irradiated to only one place of a, and the vibration of the frequency corresponding to the flexural vibration mode / torsional vibration mode of the cantilever 103 is obtained. If each is detected, it is possible to detect the amplitude, phase, and frequency by separating the flexural vibration mode and the torsional vibration mode.

Further, it is possible to induce vibration caused by heat-induced stress by irradiating the cantilever 103 with an intensity-modulated laser. By appropriately selecting the irradiation position and frequency of intensity modulation, one type of vibration in any vibration mode or by superimposing a plurality of modulation frequencies, the vibration of two or more vibration modes can be induced in the cantilever 103. Is possible.
As described above, it is necessary to irradiate the cantilever 103 with a plurality of lasers and detect reflected light in accordance with the purpose in order to detect the vibration / deformation state of the cantilever and to excite vibration of the cantilever. This irradiation position needs to be set to an appropriate position depending on the purpose of detection or vibration. Furthermore, in order to scan a large semiconductor wafer or the like with high speed and high accuracy, it is necessary to scan not the sample 501 but the cantilever 103 side. Hereinafter, examples for realizing the above-described problems will be described.

  FIG. 5 is a diagram showing an embodiment of the optical system. Reference numerals 700, 700 ′, and 700 ″ denote cantilever deformation detection laser light source / detection system units or excitation laser units. Light 130 emitted therefrom is reflected by the movable mirrors 740, 740 ′, and 740 ″, The direction is fine-tuned. These light beams include a half mirror that reflects / transmits light represented by 712 and 712 'at a certain intensity ratio, a dichroic mirror that reflects / transmits at a certain wavelength, and a polarization beam splitter that reflects / transmits depending on the polarization state. Is synthesized. Further, the light passes through the lenses 780 and 781, is reflected downward by the mirror 789, passes through the wave plate 725 as necessary, and is condensed on the cantilever 103 by the lens 790. The light reflected by the cantilever 103 is converted again into parallel light by the lens 790 and passes through when the wave plate 725 is used.

  If the quarter wave plate is used, it is possible to convert linearly polarized incident light into circularly polarized light, and to convert circularly polarized light reflected by the cantilever into linearly polarized light orthogonal to the incident light. The light transmitted through the wave plate 725 is reflected by the mirror 790, passes through the lens 781 and the lens 780, and returns to the laser light source / detection system unit / vibration laser unit 700 through the mirror 712 and the movable mirror 740. Here, the lens 790 immediately above the cantilever 103 is attached to the cantilever moving mechanism 252 to which the cantilever 103 is attached, and moves integrally with the root portion of the cantilever 103. When parallel light is incident on the lens, the relative position from the lens on the focal plane of the lens is always focused on a fixed point. With the above configuration, even if the cantilever 103 is driven and moved, It is possible to always irradiate the position.

  Since this lens 790 can be formed of a small and light lens, the cantilever drive mechanism 252 can be driven at high speed. The mirror 789 may be fixed, but in this case, the incident direction of the light irradiated on the cantilever 103 slightly changes as the lens 790 moves. If the mirror 789 is driven together with the lens 790 and the cantilever drive mechanism 252, it is possible to follow the irradiation position on the cantilever 103 while always maintaining the same incident direction, which is more preferable.

  Here, the movable mirrors 740, 740 ′, and 740 ″ will be described. These mirrors are movable mirrors having two degrees of freedom that can finely adjust the reflection direction of the laser in two directions, a direction parallel to the paper surface and a direction perpendicular to the paper surface. By changing the direction of the mirror, it is possible to move the condensing position after the lens 780 and the irradiation position on the cantilever 103 conjugate with the lens 780. Here, the irradiation direction to the cantilever 103 is changed. In order to change only the irradiation position, the positions of the movable mirrors 740, 740 ′, and 740 ″ are preferably substantially conjugate with the pupil position of the lens 790 with respect to the lens 780 and 781 system.

  As described above, according to the embodiment described above, it is possible to irradiate a plurality of beams on the cantilever 103 to cause the irradiation position to follow the scanning operation of the cantilever 103 at high speed and to adjust the irradiation position on the cantilever 103. In the above example, the case where the number of units 700 is three has been described. Needless to say, the apparatus can be similarly configured using an arbitrary number of units 700 of one or more.

  Here, an embodiment of a cantilever unit adjusted in advance will be described with reference to FIG. As described above, the detection light / excitation light irradiates the back surface of the cantilever 103 via the mirror 789, the wave plate 725, and the condenser lens 790. In this case, when the cantilever 103 is replaced, the position of the cantilever is shifted, so that the optical system needs to be adjusted again. However, if the positional relationship between the cantilever 103 and the condenser lens 790 is adjusted in advance to be a unit as shown in FIG. 13A, the angle of the unit can be adjusted even if the position of the unit is slightly shifted. If there is no variation, the condensing position on the cantilever 103 can be made by the angle of the incident light. Therefore, if a cantilever = condensing lens unit as shown in FIG. 13 (a) is used, it is possible to perform measurement immediately without attaching an optical system by simply mounting the unit. As another embodiment, as shown in FIG. 13B, in addition to the cantilever 103 and the condenser lens 790, a unit in which a mirror 789, a wave plate 725, and the like are integrated may be used.

  Here, the sample observation system will be described. The illumination light for observation is emitted from the illumination light source 154, passes through the condenser lens 153, is reflected by the beam splitter 155, passes through the objective lens 101, and illuminates the sample 501 and the cantilever 103 formed with the probe at the tip. The reflected light passes through the objective lens again, passes through the beam splitter 155, forms an image with the imaging lens 152, and is detected by the image sensor 151.

Various examples of the cantilever deformation detection laser light source / detection system unit / vibration laser unit 700 will be described below.
FIG. 6A shows an optical system for detecting the vibration state of the cantilever. The dual-frequency light generator 701 generates two beams (791 and 792) having a frequency f1, a frequency f1 + Δf, and frequencies slightly shifted. The two beams are generated by, for example, shifting the frequency by Δf by dividing the light from the laser with a beam splitter and passing one through an acoustooptic device. Alternatively, a dual-frequency laser that generates two beams having orthogonal polarization planes is also commercially available. The first beam 791 is polarized in the direction reflected by the polarization beam splitter 722 and emitted from the dual frequency light generator 701. The light 130 emitted as described above is applied to the back surface of the cantilever 103.

The light reflected here returns to the polarization beam splitter 722 after the polarization direction is rotated by 90 degrees by the effect of the quarter-wave plate 725. Since the polarization direction is rotated by 90 degrees, the polarization beam splitter 722 transmits and the next polarization beam splitter 723 also transmits.
Here, if the polarization direction of the beam 792 having the other frequency f1 + Δf emitted from the dual-frequency light generator 701 is adjusted so that the polarization direction is reflected by the polarization beam splitter 723, the beam 792 is reflected by the polarization beam splitter 723. The light is reflected from the cantilever 103 formed at the tip of the needle, and passes through the polarizing plate 721 to reach the photodiode 720.

  Although the polarization directions of the beams 791 and 792 when passing through the polarizing plate 721 are orthogonal, by tilting the polarizing plate 721 to an intermediate angle between the polarization directions of both beams, both beams cause interference, and the light intensity at the frequency Δf. Since a change occurs, this is detected by the photodiode 720. Note that a lens 729 for condensing the laser may be placed on the light receiving surface in front of the photodiode 720.

Here, the operation of the contact state detector 205 of FIG. 1 will be described.
The AC component of the detected light intensity signal A (t) is cos2π (Δft + 2Z / λ). Here, Z is the displacement due to vibration of the cantilever 103 formed with the probe tip, λ is the wavelength of the laser, and t is the time. Therefore, by detecting the phase of this signal, the displacement of the cantilever 103 having the probe formed at the tip can be obtained. For detection of the phase, the tip of the probe is made by branching a part of the two beams generated from the signal of the frequency Δf applied to the acoustooptic device in the dual-frequency light generator 701 or the two-frequency light generator 701. The signal of frequency Δf obtained by direct interference without being applied to the cantilever formed in the above may be used as a reference and input to the phase detection circuit together with A (t).

  Alternatively, if the phase difference between the light intensity signal A (t) itself and the signal A (t−Δt) obtained by delaying the light intensity signal A (t) by Δt is detected, the change component of the phase difference is 2 (Z (t) −Z (t −Δt)) / λ, the change in Z during Δt, that is, the speed of Z can be detected.

  The vibration of the cantilever 103 formed with the probe tip detected in this way is given to the signal generator 207, and a signal in a frequency band to be oscillated by a band pass filter is selected, and an appropriate phase difference and gain are given. The cantilever 103 having the probe formed at the tip is vibrated by being fed back to the cantilever 103 having the probe formed at the tip via the cantilever driving unit 202 having the probe formed at the tip. Alternatively, the light intensity applied to the vibration excitation light source 702 and applied to the cantilever 103 formed with the probe tip is modulated, and the cantilever 103 formed with the probe tip is directly excited. When the phase difference and gain are set appropriately, a cantilever with a probe formed at the tip causes vibration with a required amplitude.

  In this embodiment, so-called heterodyne detection using two-frequency light is used, but homodyne detection using light of a single frequency may be used instead. In this case, the light having the frequency f1 is branched and used as the reference light 792 and detected on the photodiode, but the laser is branched by the half mirror 726 as shown in FIG. 7 in order to detect the phase. Then, one is reflected by the mirror 727, the phase difference between the reference light and the detection light is shifted by 90 degrees by the λ / 4 plate 728, and then interfered by the polarizing plate 721 ′, and then passed through the lens 729 ′ and the second photodiode 720 ′ Detect with. First and second, the signals from the photodiodes 720 and 720 ′ become signals corresponding to cos and sin, and after detecting the amplitude of the component corresponding to the resonance frequency of each signal, the square root of the sum of squares is obtained. For example, the vibration amplitude of a cantilever with a probe tip formed at the tip can be detected.

となる。ここで、カンチレバー１０３の振幅をｂ、ミラー７９６の振幅をｃ、レーザ波長をλとしている。θ、ω、ξは各部の位相である。２ｇ成分が０となる状態は、正弦波の位相が０あるいは１８０度の場合であるので、ξが０にに保たれていることになる。ｂがλに比較して十分小さいとすると、ｈ周波数成分を取り出した干渉信号は、

となり、これからカンチレバー１０３の振動の振幅ｂと位相θを検出することが可能となる。ユニット７００の別の実施例として、図２、３で説明した反射光の角度変化でカンチレバー１０３の変形を検出する方法の具体的光学系の実施例を示す。図８のように、レーザダイオードあるいはＬＳＤ（スーパールミネッセントダイオード）などの高輝度の光源１３１から出射した光をレンズ１３２でコリメートして、偏光ビームスプリッタ１３３を通して出射させる、戻ってきた光は偏光ビームスプリッタ１３３で反射して、ポジションセンサ１３６に入射する。ポジションセンサ１３６は分割型のフォトダイオードであったり、ポジションセンシティブデバイスと呼ばれる光の入射位置に応じた出力を生じるセンサであったりする。これによって、カンチレバー１０３の変形を検出することが可能となる。ユニット７００を２式用いて、カンチレバー１０３上の異なる位置に照射するように調整すると、図３で説明したように、カンチレバー１０３の先端の探針１０４にかかる力をより詳細に分解して検出することも可能となる。 As another embodiment, as shown in FIG. 6B, the mirror 796 is movable by a fine actuator 796, the optical path length of the reference light 792 is variable, the mirror 796 is vibrated at a frequency g, and a photodiode is formed by a lock-in amplifier. If the interference signal output of 720 is synchronously detected and the offset position of the mirror 796 is made to follow so that the double frequency 2g component of the frequency g becomes 0, the phase difference between the measurement light 130 and the reference light 792 is 90 degrees or − It can be kept at 90 degrees. In this state, the offset position of the mirror 796 is proportional to the displacement of the cantilever 103. The amplitude corresponding to the vibration frequency h of the cantilever 103 of the interference signal output is proportional to the amplitude of the cantilever 103. When expressed as an equation, the interference signal is

It becomes. Here, the amplitude of the cantilever 103 is b, the amplitude of the mirror 796 is c, and the laser wavelength is λ. θ, ω, and ξ are phases of each part. The state in which the 2g component is 0 is when the phase of the sine wave is 0 or 180 degrees, so that ξ is kept at 0. If b is sufficiently smaller than λ, the interference signal from which the h frequency component is extracted is

Thus, the vibration amplitude b and phase θ of the cantilever 103 can be detected. As another embodiment of the unit 700, an embodiment of a specific optical system of the method for detecting the deformation of the cantilever 103 by changing the angle of the reflected light described with reference to FIGS. As shown in FIG. 8, the light emitted from the high-intensity light source 131 such as a laser diode or LSD (super luminescent diode) is collimated by the lens 132 and emitted through the polarization beam splitter 133. The returned light is polarized. The light is reflected by the beam splitter 133 and enters the position sensor 136. The position sensor 136 is a split type photodiode or a sensor called a position sensitive device that generates an output corresponding to the incident position of light. As a result, the deformation of the cantilever 103 can be detected. When the two units 700 are used to adjust to irradiate different positions on the cantilever 103, the force applied to the probe 104 at the tip of the cantilever 103 is detected in more detail as described with reference to FIG. It is also possible.

  Next, an embodiment in which optical excitation vibration is induced in the cantilever 103 will be described with reference to FIG. Light emitted from a high-intensity light source 702 such as a laser diode or LSD (super luminescent diode) is collimated by a lens 711 and emitted. Here, light induced vibration can be induced in the cantilever 103 by modulating the driving current 702. Here, in order to prevent the return light from returning to the light source 702, a polarization beam splitter may be inserted into the position 703 or a photo isolator may be inserted into the position 703 in the same manner as in FIG. .

  Further, as another embodiment of the embodiment described with reference to FIGS. 6A and 6B, as shown in FIGS. 10A and 10B, polarization beam splitters 722 and 723, respectively. Are changed to half mirrors 722 ′ and 723 ′, and both the measurement light 791 and the reference light 792 are directed toward the cantilever 103. Here, an element 795 that bends the direction of the light beam is inserted into one of the measurement light 791 and the reference light 792, and the measurement light 791 and the reference light 792 are positioned at different positions on the cantilever as shown in FIG. To irradiate. The returned light causes interference by the polarizing plate 792, passes through the lens 729, and obtains an interference signal by the photodiode 720. Here, the element 795 that bends the direction of the light beam may be configured by using a movable mirror such as 740 in FIG. 5, or wedge-shaped glass. By rotating the wedge-shaped glass, the optical axis shift direction can be changed. If the two wedge-shaped glasses are rotated relative to each other, not only the shift direction but also the shift amount can be freely adjusted.

  Next, FIG. 11 is used to show another embodiment of the invention described with reference to FIG. The light emitted from the cantilever deformation detection light source / detection system unit / excitation laser unit 700 is condensed on the end surface of the optical fiber 789 by the condenser lens 780, and the light passing through the optical fiber 789 is parallel by the lens 781. It is converted into light and combined with light from another unit 700 ′ by the dichroic mirror 712. Thereafter, the cantilever 103 is irradiated through the same optical path as described with reference to FIG. 5, and the reflected light returns and is condensed on the end face of the fiber 789 by the lens 781. The light that has passed through the fiber 789 is collimated by the lens 780 and input to the laser light source / detection system unit 700 for cantilever deformation detection. Here, if the position of the exit end of the fiber 789 is changed by a stage mechanism (not shown), the position of the exit end is imaged on the cantilever 103, so that the irradiation position on the cantilever can be adjusted. However, when this optical system is used, the deformation of the cantilever 103 cannot be detected by a method of detecting a change in the reflection direction.

  As another embodiment, as shown in FIG. 12, a method of condensing the light emitted from the lens 780 on the pupil plane of the objective lens 101 via the half mirror 789 'will be described. This light is converted into parallel light by the objective lens 101 and is emitted from the objective lens 101. The light is condensed on the cantilever 103 via a minute quarter-wave plate 725 and a lens 790 placed under this. The light reflected by the cantilever 103 returns along the optical path from which it came. Here, by rotating the movable mirror 740, the condensing position on the pupil of the objective lens 101 can be adjusted. Since this is projected onto the cantilever 103 by the objective lens 101 and the lens 790, the irradiation position on the cantilever 103 can be adjusted by the movable mirror 740.

  According to the present invention, it is possible to optically detect the contact state between the probe and the sample and vibrate the probe while driving the probe of the scanning probe microscope at a very high speed. Observation and measurement with a high-speed scanning probe microscope corresponding to a sample such as a flat display substrate that cannot be driven on the sample side becomes possible.

FIG. 1 is a diagram showing an overall configuration of a scanning probe microscope. FIG. 2 is a diagram showing the principle of detecting cantilever deformation by the reflection angle of light rays. FIG. 3 is a diagram illustrating Example 1 in which the forces in the x and z directions applied to the probe are separated and detected based on the reflection angles of a plurality of light beams applied to the cantilever. FIG. 4 is a diagram showing an embodiment in which the deformation of the cantilever is detected by optical interference. FIG. 5 is a detailed view showing Example 2 of the optical system. FIG. 6 is a diagram illustrating an example of a light source and a detection system for interference detection. FIG. 7 is a diagram illustrating another example of a light source for interference detection and a detection system. FIG. 8 is a diagram illustrating an example of a light source and a detection system for detecting a reflection angle. FIG. 9 is a diagram illustrating an example of a light source of a laser excitation optical system. FIG. 10 is a diagram showing still another embodiment of a light source for detection of interference and a detection system. FIG. 11 is a detailed view showing Example 3 of the optical system using the optical fiber. FIG. 12 is a detailed diagram showing a fourth embodiment for guiding the detection / excitation light through the objective lens. FIG. 13 is a diagram showing a pre-adjusted cantilever and condenser lens unit of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 Objective lens 102 Lens tube 103 Cantilever formed with a tip at the tip 104 Probe 116 Position sensor 130 Detection light 131 Light source 132 Collimator lens 133 Beam splitter 154 Illumination light source 153 Condenser lens 155 Beam splitter 152 Imaging lens 151 Image sensor 201 Scanning Control unit 202 Cantilever drive unit 203 Cantilever holder drive unit 204 Proximity sensor 205 Contact state detector 206 Optical image sensor 207 Signal application device 208 SPM image forming device 250 Overall control device 251 Input / display device 252 Cantilever moving mechanism 253 Probe tip Cantilever holder up-and-down mechanism formed on 302 Sample stage 311 Robot arm 501 Sample 700 Laser light source for detecting cantilever deformation System unit / Excitation laser unit 701 Dual frequency light generator 702 Vibration excitation light source 712 Dichroic mirror 722 Polarizing beam splitter 723 Polarizing beam splitter 722 'Half mirror 723' Half mirror 720 Photo diode 721 Polarizing plate 725 Wavelength plate 727 Mirror 729 Lens 780 Lens 781 Lens 789 Prism mirror 795 Mirror 796 Fine movement actuator

Claims (8)

  A drive mechanism that controls the mutual positional relationship between a sample stage on which a sample is placed and a cantilever provided with a probe; and a sensor that optically measures the deformation state of the cantilever, including the three-dimensional surface shape of the sample. A scanning probe microscope for measuring a surface distribution of a sample, the scanning probe microscope comprising an optical microscope for observing the cantilever and the sample, wherein at least one optical element among components of a sensor for optically measuring the deformation state of the cantilever is A scanning probe microscope, which is disposed between the optical microscope and the sample and is driven integrally with the driving mechanism.   2. The scanning probe microscope according to claim 1, further comprising an optical system that is thermally deformed by irradiating light to the cantilever including the probe, wherein the optical microscope and the sample are included in the components of the optical system. A scanning probe microscope characterized in that at least one optical element disposed therebetween is shared with a sensor for optically measuring the deformation state of the cantilever.   3. The scanning probe microscope according to claim 2, wherein vibration of the probe is excited by intensity modulation of light applied to the cantilever provided with the probe.   2. The scanning probe microscope according to claim 1, wherein an electric signal is given to the probe or a probe holding unit for holding the probe or a driving mechanism for controlling a mutual position of the probe and the sample stage. The scanning probe microscope is characterized in that vibration of the probe is excited by.   The scanning probe microscope according to claim 1, wherein deformation or vibration of the probe is detected using interference of laser light applied to the cantilever provided with the probe.   2. The scanning probe microscope according to claim 1, wherein deformation or vibration of the probe is detected by using a change in a reflection angle of light irradiated to the cantilever provided with the probe. .   A probe unit for a scanning probe microscope in which a condenser lens is integrated with a cantilever equipped with a probe, and is aligned so that the cantilever comes to a focal position of the condenser lens.   8. The probe unit for a scanning probe microscope according to claim 7, wherein in addition to the condensing lens, an optical element including a mirror and / or a wave plate is integrated with a cantilever provided with a probe, A probe unit for a scanning probe microscope that is positioned so that the cantilever is at the focal point.

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