JP3061955B2 - Scanning probe microscope, memory device and lithography device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scanning probe microscope apparatus, a memory apparatus, and a lithography apparatus having a position shift correction function.

[0002]

2. Description of the Related Art In recent years, a scanning probe microscope (SPM) far exceeding the resolution of a conventional electron microscope has been put into practical use, and the surface of various samples can be observed with a resolution of 0.1 nanometer or less. . In SPM, a probe with a sharpened tip is brought close to the sample surface to a distance of about 1 nanometer or less, and the physical quantity generated between them is detected. The probe is two-dimensionally scanned over the sample surface. Then, an SPM image is obtained by mapping a physical quantity at each point on the sample surface in a two-dimensional manner.

[0003] The physical quantities include a tunnel current and an atomic force, and the like, whereby the SPM is classified into various types such as a scanning tunneling microscope (STM) and an atomic force microscope (AFM).

Actually, when the surface of a sample is observed using the SPM, the probe is moved in the lateral direction relative to the sample due to relaxation of mechanical strain and temperature drift caused when the sample or the probe is replaced. A position shift occurs, and the SPM observation image is shifted or distorted. The relaxation time of the displacement is generally about 2 to 5 hours. SPM observation and SPM configuration
In a lithography device or memory device that applies the principle, if you try to perform detailed observation, precise processing, recording, reproduction, and erasing of an area on the order of 1 to 10 nanometers or less, you must wait a long time after setting the device. And there is a problem that the working efficiency is reduced.

Therefore, in the STM, the following speed is determined from the displacement speed of the STM observation image, a signal whose magnitude changes at a constant speed is applied to the lateral driving element of the probe, and the lateral speed due to the drift between the probe and the sample is determined. Japanese Patent Laid-Open No. 3-152845 proposes to follow the positional deviation at a constant speed.
No. 6,009,036.

[0006]

However, in the above-mentioned conventional example, since the following speed is determined from the positional deviation speed of the STM observation image, if the positional deviation speed changes due to relaxation of the positional deviation, the following speed must be readjusted accordingly. There is a problem that it is necessary and takes time.

Further, when the displacement speed is large immediately after setting the apparatus, there is a problem that the distortion of the STM image due to the displacement is large and it is difficult to adjust the following speed.

Further, when the observation is performed for a long time or when the displacement speed is large even in a short time, the displacement amount may exceed the optimum control range of the follow-up actuator. And the other coarse actuator had to be driven.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and it has been found that a relative displacement between the probe and the sample occurs for a long time immediately after setting the apparatus. It is intended to realize a device without any.

[0010]

A scanning probe microscope according to the present invention comprises a probe arranged such that the tip is opposed to and close to the surface of a sample, and the probe is arranged on the sample. Orthogonal to the facing direction of, and scanning means for scanning relatively to a predetermined course, and detecting means for detecting a physical quantity generated between the sample and the probe, when scanning by the scanning means In a scanning probe microscope for observing the sample surface from the detection result of the detection means, when scanning the probe, detect the relative position of the sample and the probe in a direction orthogonal to the facing direction of the sample and the probe, A displacement detection means for outputting a first displacement detection signal indicating the content of the detection, a signal component associated with scanning between the sample and the probe is removed from the first displacement detection signal, Output as a position shift detection signal It has a scanning signal No. component removing means, and correction means for sequentially correcting a positional deviation between the sample and the probe on the basis of the second deviation amount detection signal.

In this case, the scanning signal component removing means may be a low-pass filter having a cutoff frequency lower than the scanning frequency between the sample and the probe.

Further, the scanning signal component removing means may sample the displacement detection signal at a timing synchronized with the scanning between the sample and the probe.

In this case, the scanning signal component removing means may interpolate between sampling points.

Further, the scanning performed by the scanning means may be performed by a smooth return signal near the turning point, and the sampling operation by the scanning signal component removing means may be performed near the turning point.

[0015] Further, each of the above described positional deviation detecting means may be constituted by a light wave interferometer.

The light wave interferometer includes a mirror fixed to a member for fixing the sample, a mirror fixed to a member for fixing the probe, and means for making coherent light incident on one of the mirrors; Means for separating a part of the coherent light, changing the optical path to make it incident on the other side of the mirror, and means for calculating a relative movement amount of the mirror based on a composite light intensity signal of two reflected lights from the mirror And a differential type light wave interferometer comprising:

Further, the light wave interferometer includes a mirror fixed to one of a member for fixing the sample and a member for fixing the probe, an optical fiber fixed to the other and arranged with the end face close to the mirror. A means for inputting coherent light to a mirror through an optical fiber and a mirror relative to an end face of the optical fiber based on a composite light intensity signal of light reflected by the mirror and passed through the optical fiber again and light obtained by separating a part of the coherent light in advance. An optical fiber interferometer including means for calculating a target movement amount may be used.

In each of the above structures, the correction means includes an estimation circuit for estimating a temporal change in the displacement based on the second displacement detection signal output by the scanning signal component removing means, and the estimation circuit. And a subtraction circuit that corrects a displacement between the sample and the probe based on the estimation result of the above and a set position corresponding to a predetermined course.

The estimating operation of the estimating circuit may target at least one or more displacements due to relaxation times of different time constants and estimate the intensities and time constants of these components.

Further, the estimating circuit outputs the second input signal when the difference between the input second displacement signal and the estimated value from the second displacement signal before the input exceeds a predetermined value. The estimation value from the second displacement amount signal before the input may be output without performing the estimation based on the displacement amount signal.

Each of the above-mentioned correction means includes a first actuator and a second actuator for performing movement including the first actuator.
These actuators may be used to correct the displacement between the sample and the probe.

Further, the memory device and the lithography device of the present invention use the above-described configuration of the scanning probe microscope.

[0023]

The correction operation performed in the present invention is sequentially performed based on a pure displacement amount from which a scanning signal component caused by the scanning of the probe has been removed. Correction of the relative displacement between the probe and the sample caused by the relaxation of the mechanical strain or the temperature drift can be performed accurately without the need for readjustment.

An estimating circuit is provided in the correcting means for performing the above-described correction, and the positional deviation is corrected based on the result of estimating the relative positional deviation between the probe and the sample caused by relaxation of mechanical distortion, temperature drift, and the like. In such a case, since the correction is performed based on the relative displacement, the malfunction due to sudden mechanical or electrical noise is prevented.

[0025]

Next, embodiments of the present invention will be described with reference to the drawings.

FIGS. 1 and 2 are a sectional view and a top view, respectively, showing the arrangement of an optical system of a displacement detecting means according to an embodiment of the present invention.

With respect to the optical system of the present embodiment, first, a system in the z-axis direction will be described with reference to FIG.

The probe 102 is moved with respect to the sample 101 by xy in the figure.
XY drive element 103 that relatively scans in the direction
Attach 104. On the other hand, coherent lights of two wavelengths λ ₁ and λ ₂ polarized in mutually orthogonal directions are
It is introduced into the device housing 106 through the inside. The light emitted from the end face of the polarization maintaining fiber 105 becomes parallel light by the collimator lens 107,
108. A part of the incident light is reflected, enters the sensor R101 through the polarizing plate R109, and becomes a reference light intensity signal. The other is divided into four, and one of them is incident on the polarization beam splitter A111.

Here, the two-wavelength lights orthogonally polarized to each other are split into two, one is reflected by the mirror A104 through the quarter-wave phase plate A112, and the other is reflected by the quarter-wave phase plate A'113. The light passes through and is reflected by the mirror A'114. 2
The two reflected lights are combined by the polarizing beam splitter A111, pass through the polarizing plate A115, enter the sensor A116, and become the light intensity signal A.

Since both the reference light intensity signal and the light intensity signal A are synthesized lights of two wavelengths (λ ₁ , λ ₂ ), the light intensity signal has a frequency Δf = C (1 / λ ₁ -1). / Λ ₂ ). Here, C is the speed of light. By detecting the phase difference of the vibration component of the frequency Δf in the reference light intensity signal and the light intensity signal A by the synchronization detection circuit, the relative movement amount of the mirror A 104 and the mirror A ′ 114 in the x direction is detected. For example, if the wavelength of the two-wavelength coherent light is λ ₁ ≒ λ ₂ = 67
Assuming that 0 nm and Δf = 1 MHz, the change 2π radians in the phase of the vibration component of the signal A with respect to the vibration component of the reference signal corresponds to the relative movement amount 335 (= 670/2) nm in the x direction of the mirror A 104 and the mirror A ′ 114. . Further, by measuring the phase difference precisely by dividing the phase by 100 to 1000, the relative movement amount can be detected with a resolution of 3 to 0.3 nm.

Next, an optical system according to the present embodiment on the xy plane will be described with reference to FIG.

The parallel light emitted from the collimator lens 107 is incident on the beam splitter 201 except that a part of the parallel light is incident on the sensor R110, and is divided into two parts, and further divided into four parts by the beam splitters 202 and 203. These lights are supplied to a polarizing beam splitter, a phase plate, and mirrors B205, C204, D206, B'117, C '(not shown), and D' (not shown) provided in the same manner as described above. , Incident or reflected, each combined light passes through a polarizing plate provided for each of the sensors B208, C
207 and D209, and the respective light intensity signals B and
C and D are obtained. By detecting the phase difference between the vibration components of the light intensity signals B, C and D and the vibration component of the reference signal, the relative movement amount of the mirror B205 and the mirror B'117 in the x direction and the mirror C204 and the mirror C ′ (not shown), and the relative movement amount of the mirror D206 and the mirror D ′ (not shown) in the y direction are detected.

The mirrors A104 and A'114, the mirror B205 and the mirror B'117 are arranged at positions symmetrical with respect to the probe 102 and the sample 101 in the x direction.
The average of the x-direction relative movement of the mirror 104 and the mirror A'114 and the x-direction relative movement of the mirror B205 and the mirror B'117 is defined as the x-direction relative movement of the probe 102 and the sample 101.
Similarly, mirror C204 and mirror C '(not shown), mirror D206 and mirror D' (not shown) are also arranged at positions symmetrical in the y direction with respect to probe 102 and sample 101, and mirror C
The average of the relative movement amounts of the mirror 204 and the mirror C ′ (not shown) in the y direction and the relative movement amounts of the mirrors D206 and D ′ (not shown) in the y direction are defined as the relative movement amounts of the probe 102 and the sample 101 in the y direction. The optical system of the present embodiment is an optical system that does not affect the relative movement amount detection accuracy in the xy directions due to the relative movement of the probe 102 and the sample 101 in the z direction.

FIG. 3 is a diagram for explaining the configuration of an apparatus for introducing two-wavelength coherent light polarized in mutually orthogonal directions into a polarization maintaining fiber.

In FIG. 3, the coherent light of wavelength λ ₁ emitted from the semiconductor laser 301 is converted into a parallel light by a collimator lens 302, and an S-polarized light component in a direction perpendicular to the paper and a parallel light to the paper by a first polarizing beam splitter 303. And P-polarized light components in different directions. The S-polarized light component is the first mirror 3
After being reflected at 04, the light is incident on the second polarization beam splitter 305. After the P-polarized component is reflected by the second mirror 306,
An acousto-optic modulator 307 modulates the frequency by Δf,
To shift the wavelength λ _2. Here, between λ ₁ , λ ₂ and Δf, Δf = C (1 / λ ₁ −1 / λ ₂ ) as described above.
There is a relationship. The P-polarized component having the wavelength λ ₂ is further incident on the second polarization beam splitter 305, combined with the S-polarized component, condensed by the condenser lens 308, and introduced into the polarization preserving fiber 309.

Referring again to FIG. 1, a scanning probe microscope (SPM) to which the present invention is applied will be described.

In the scanning probe microscope, the tip of the probe 102 with respect to the surface of the sample 101 is moved 1n by the z drive element 118.
m or less. Further, the xy two-dimensional scanning signal from the xy scanning signal circuit 119 and the xy scanning signal circuit 119 together with the xy driving circuit 1
20 and an xy two-dimensional drive signal is input to the xy drive element 103 to cause the probe 102 to perform xy two-dimensional scanning relative to the sample 101. At this time, an SPM image is obtained by detecting a physical quantity between the tip of the probe 102 at each position on the surface of the sample 101 and forming a two-dimensional map. The physical quantity at this time includes, for example, a tunnel current (scanning tunnel microscope: STM) flowing between the tip and the sample when a bias voltage is applied, an atomic force acting between the tip and the sample, van der Waals Force, frictional force, magnetic force (atomic force microscope: AFM, friction force microscope: FFM, magnetic force microscope: MFM), probe irradiating light from behind (optical fiber with sharp tip, glass surface with sharp tip) Evanescent light (photon scanning tunneling microscope: PST) oozing from the surface of a sample or a thin metal coated with an opening with a diameter of 1 μm or less at the tip
M, near-field light microscope (NFOM), etc., and these microscopes are collectively called SPM.

In the SPM, as a method of two-dimensionally scanning the tip of the probe 102 with respect to the surface of the sample 101, a raster scan as shown in FIG. 4 is usually performed. This performs x scanning at a speed sufficiently higher than the scanning speed in the y direction, and
This is a scanning method in which the scanning lines in the direction are shifted little by little in the y direction to fill one screen. In the drawing, the solid line indicates forward scanning in the y direction, and the broken line indicates backward scanning. The solid line (broken line) with a rightward arrow indicates forward scanning in the x direction, and the leftward arrow indicates a return scan in the x direction. Now, with respect to the sample 101, the probe 1
As long as 02 does not cause any displacement other than scanning in the xy directions, as shown in FIG. 4, the scanning regions of the reciprocating scanning in the y direction overlap, and the measurement regions in the SPM are not displaced or distorted.

However, in the actual measurement, the probe is moved in the xy direction relative to the sample during the SPM measurement due to relaxation of the mechanical strain generated when the sample or the probe is replaced, temperature drift, and the like. A shift is caused, and the measurement area is shifted or distorted. Since this displacement occurs on the order of a longer time than the SPM measurement time (especially the time to obtain one screen), a phenomenon that occurs during the SPM measurement is a certain speed in the x direction as shown in FIG. The distortion of the measurement area caused by the displacement, the enlargement or reduction of the measurement area caused by the displacement at a certain speed in the y direction as shown in FIG. 6, or the case of FIGS. 5 and 6. Appear in the form of distortion and enlargement / reduction of the measurement area caused by displacement at a certain speed in a certain direction in the xy plane as if there is a mixture.

A method for correcting the relative displacement of the probe in the xy direction with respect to the sample in order to prevent such distortion and enlargement / reduction of the measurement area will be described below.

FIG. 7 is a diagram showing a signal processing circuit 721 for correcting displacement in the x direction, and FIG. 8 is an example of a signal obtained at several points in FIG. 7, and the operation of the signal processing circuit shown in FIG. FIG.

The output current signals of the vibration component of the frequency Δf from the sensor A (116 in FIG. 1), the sensor R (110 in FIG. 1), and the sensor B (208 in FIG. 1) are converted into current / voltage conversion circuits 701 to 703. Each is converted into a voltage signal.

Outputs of the current / voltage conversion circuits 701 to 703 are input to synchronization detection circuits 704 to 707. Current /
The output of the voltage conversion circuit 701 is output to the synchronization detection circuits 704, 70
5, respectively. The output of the current / voltage conversion circuit 702 is input to the synchronization detection circuits 704, 707.
After passing through the phase shifter 708, the synchronization detection circuits 705, 7
06. The output of the current / voltage conversion circuit 703 is input to the synchronization detection circuits 706 and 707, respectively.

As described above, a part of the signal from the sensor R is transmitted to the mirror A104, the mirror A'114, and the mirror B2.
In order to detect the relative movement direction of the mirror 05 and the mirror B ′ 117 in the x direction, the phase shifter 708 shifts the phase by １ ／ cycle of the vibration of the frequency Δf, and
5,706.

Outputs from the synchronization detection circuits 704 to 707 are input to low-pass filters 709 to 712, respectively. Counter 7 is used as movement amount signals S71 and S74 indicating movement amounts output from low-pass filters 709 and 712.
13 and 716, respectively.
The movement amount signals S72 and S73 output by the signals 10, 711 are
By passing through the binarization circuits 714 and 715, the counter 71 generates moving direction signals S75 and S76 indicating the moving direction.
3,716.

In the counters 713 and 716, movement amount signals S71 to S 'of mirrors A and A' and mirrors B and B '
X indicating the relative displacement of the mirrors A and A ′ and the mirrors B and B ′ in the x direction from the movement direction signals S75 and S76.
The direction relative position shift amount signals S77 and S78 are calculated and output to the averaging circuit 717. The sign of the signal at this time is positive in the positive direction of x in FIG.

The averaging circuit 717 averages the relative displacements in the x direction between the mirrors A and A 'and the mirrors B and B' indicated by the relative displacement signals in the x direction S77 and S78, and obtains the sample 101 and the probe 102. And outputs it to the low-pass filter 718 as the x-direction relative position shift amount signal 8b which is the first position shift amount detection signal. Here, in the x-direction relative displacement signal 8b, a displacement component caused by relaxation of mechanical distortion and a temperature drift and an x-direction scanning component are mixed.
Of the above-described configuration of the signal processing circuit 721, the current / voltage conversion circuits 701 to 703 constitute a detection unit, and the other part constitutes a signal processing system of the displacement detection unit.

FIGS. 8A to 8C show the x-scanning signal 8a, the x-direction relative displacement signal 8b, and the output 8c of the low-pass filter 718, respectively.

By passing the relative displacement signal 8b in the x direction through the low-pass filter 718, a displacement signal (second displacement detection signal) excluding the scanning component in the x direction is obtained as the output 8c of the low-pass filter 718. The output 8c of the low-pass filter 718 is passed through an estimating circuit 722 to be described later, an error signal between the output and a preset x-direction position is calculated by a subtraction circuit 719, amplified by an amplification circuit 720, and then amplified by an x-position correction signal circuit 721. As the output of
The signal is input to the x-direction drive circuit 120, and thereafter, feedback control is performed so that the x-direction positional relationship between the sample 101 and the probe 102 becomes a set position.

A typical frequency band of a signal in the signal processing circuit 721 for performing the displacement correction in the x direction shown in FIGS. 7 and 8 will be exemplified. Output signals of the sensors A, R, and B and input signals of the synchronization detection circuits 704 to 707 to 1 MHz (= Δ
f), the output signals of the low-pass filters 709 to 712, the output signals 8b to 10 kHz of the averaging circuit 717, the x-direction scanning signals 8a to 100Hz, the output signals of the low-pass filter 718, and the output signals of the amplifier circuit 720 to 1 Hz.

FIG. 9 is a diagram showing a signal processing circuit for correcting a displacement in the y direction, and FIG. 10 is a diagram showing examples of signals obtained at several points in FIG.

A current / voltage conversion circuit 901 for inputting output current signals of the vibration component of the frequency Δf from the sensor C (207 in FIG. 2), the sensor R (110 in FIG. 2), and the sensor D (209 in FIG. 2). To 903, synchronization detection circuits 904 to 907 for performing subsequent processing, phase shifters 908, low-pass filters 909 to 912, movement amount signals S91 to S94 output by each low-pass filter, counters 913, 916, and relative positions output by each counter. Shift amount signals S96, S97, binarization circuits 914, 91
5. Moving direction signals S95, S9 output by each binarization circuit
Up to 6 is the same as the signal processing circuit for correcting the displacement in the x direction described above.

The average of the relative displacements in the y direction between the mirror C204 and the mirror C '(not shown) and between the mirror D206 and the mirror D' (not shown) in the averaging circuit 917 is calculated as the y between the sample 101 and the probe 102. The direction relative position shift amount signal 10b is assumed.

FIGS. 10A to 10E show the y-direction scanning signal 10a and the y-direction relative displacement signal 10b, y, respectively.
A direction scanning synchronization signal 10c, a y-direction displacement amount sampling signal 10d, and an interpolation signal 10e are shown.

As shown in the figure, the y-direction relative displacement signal 10b contains both the y-direction displacement component and the y-direction scanning component. The scanning frequency in the y direction is lower than the scanning frequency in the x direction, and overlaps with the frequency band of the displacement component caused by relaxation of mechanical distortion and temperature drift. Therefore, unlike the case of the above-described displacement in the x direction, it is difficult to separate the displacement component and the scanning component in the y direction by the low-pass filter. Therefore, a y-direction scanning synchronization signal 10c synchronized with the y-direction scanning signal 10a is generated, and in synchronization with this, a sampling circuit 918 samples the y-direction relative position shift amount signal 10b. The sampling signal 10d for the displacement in the y direction is input to the interpolation circuit 919, and the interpolation between the sampling points is performed as an interpolation signal 10e. As an interpolation method, it is desirable to perform interpolation using a quadratic or higher-order curve such that the interpolation signal is smooth and does not bend. An estimating circuit 920, which will be described later, converts the interpolation signal 10e.
, An error signal between the output and a preset y-direction position is calculated by a subtraction circuit 921,
After that, the signal is input to the y-direction drive circuit 120 as an output of the y-position correction signal circuit 923, and thereafter, the sample 101 and the probe 1
The feedback control is performed so that the positional relationship in the y direction with respect to 02 becomes the set position.

A typical frequency band of a signal in the y-direction displacement correction signal processing circuit shown in FIGS. 9 and 10 is illustrated.
Output signals of sensors C, R, D and synchronization detection circuit 904
907 to 1 MHz (= Δf), output signals of low-pass filters 909 to 912 and averaging circuit 917
Output signal ~ 100Hz, y direction scanning signal ~ 10Hz,
Output signals of the interpolation circuit 919 and the estimation circuit 920 are up to 1 Hz.

Next, the estimating circuit 7 will be described with reference to FIGS.
22 and 920 will be described.

Although the displacement is caused by a plurality of factors,
As the time elapses, the positional deviation due to the relatively short relaxation time decreases, and the positional deviation due to the long relaxation time becomes dominant. This is shown in FIG. The displacement signals in the x and y directions input to the estimating circuit include a displacement component having a relatively short relaxation time as shown by 1 to n in the drawing and a position having a long relaxation time as shown by a dotted line after n + 3. This is a form in which a plurality of these components are combined from the shift components or as shown in FIG.
When such a displacement signal ΔS is expressed as a mathematical expression with time as t, ΔS = {A ₁ exp (−B ₁ t) + A ₂ exp (−B ₂ t) +... + Ct + D}
・ ΔX + ｛E ₁ exp (−F ₁ t) + E ₂ exp (−F ₂ t) +... + Gt +
H｝ · ΔY where A ₁ , A ₂ , ..., B ₁ , B ₂ , ..., C, D, E ₁ , E ₂ , ...,
_{F 1, F 2, ...,} G, H is a _{constant, B 1, B 2, ...} , F 1, F 2, ... are positive, X, Y are each x, represents the unit vector of the position in the y-direction.

The position shift signals ΔS in the x and y directions input to the estimation circuits 722 and 920 are calculated at a plurality of times t = t ₁ , t ₂ , t
_3, ..., sampled at t _n, the constant A ₁ in formula above this value, A _2, ..., G, and calculates the H. Using this constant value, the displacement signal Δ at t = t _{n + 1} , t _{n + 2} ,.
S can be inferred. Thus, multiple times t = t
_1, t _2, ..., based on the position deviation signal at t _n, since the t
= T _{n + 1} , t _{n + 2} ,..., And a feedback control of the displacement correction is performed based on this value. Therefore, even if sudden mechanical or electrical noise is mixed in the position shift signal, it is possible to judge that noise is mixed by comparing the signal immediately before mixing and the signal after mixing.
By removing the mixed signal and using the estimated value as the displacement correction signal instead, it is possible to prevent malfunction of the feedback control. In addition, since the amount of displacement can be predicted when the time has elapsed, the amount of displacement can be estimated when the time has elapsed. The optimal control range of the actuator for correcting the displacement (the xy drive element 103 in FIG. 1 in this embodiment). Is exceeded, the sample 101 and the probe 102 are moved in advance by another xy coarse actuator (not shown in FIG. 1).
The movement can be relatively coarse in the direction, and the control can be performed at the optimal control position for the actuator for correcting the positional deviation after the lapse of time.

In the correction operation by the above-described signal processing performed in the present embodiment, the accuracy naturally increases as the number of samplings increases. However, as shown in FIGS. In this case, there is no particular problem because the displacement is mainly caused by a factor having a relatively short relaxation time which is different from the main factor of the displacement thereafter. Further, as the number of samplings increases, the calculation time spent for making the estimation also increases, so that the correction operation cannot be followed depending on the sampling interval. However, since the number of samplings in such a state is sufficient to achieve the required accuracy, the sampling interval may be increased, for example, the sampling interval may be gradually increased in accordance with the increase in the number of samplings. It is good also as a structure which performs.

In this embodiment, as an interference optical system for detecting the relative movement amount of the sample and the probe, a differential type (= movement amount of mirrors A and A ') as shown in FIGS. ), But the present invention is not limited to this, and other interference optical systems,
For example, as shown in the sectional view of FIG. 13 and the top view of FIG.
A heterodyne light wave interferometer using a fiber may be used.

13 and 14, fiber fixtures A to D (1307, 1322, 1401, 1402)
Are fixed to the lower unit of the apparatus housing 1308, and mirrors A to D (1305, 1306, 1405, 140)
6), the polarization-preserving fibers A to D (1
309, 1321, 1403, and 1404), reflected from the mirrors A to D, and returned to the fibers A to D again. The linearly polarized two-wavelength coherent light source 1310 constituting the above detection system has the same configuration as that shown in FIG.
311, polarizing plate 1312, 1319, sensor R131
3. Polarizing beam splitter 1314, quarter wave plate 13
The separation operation and the detection operation by 15, 1317, lens 1316, mirror 1318, and sensor A 1320 are the same as those in the embodiment shown in FIGS.

The optical systems shown in FIGS. 13 and 14 are also xy by the relative movement of the probe 1302 and the sample 1301 in the z direction.
The optical system does not affect the detection accuracy of the relative movement amount in the direction.

In this embodiment, the xy-direction displacement correction is performed by using the SP
Although the example applied to M is shown, the concept of the present invention is not limited to this, and the same positional deviation correction accuracy (up to 1 nm) as SPM is required, and the periodic relative xy between the probe and the sample is used.
The present invention can be applied to a device that performs directional scanning, for example, a memory device in which a sample is replaced with a memory medium or a lithography device in which a sample is replaced with a lithography medium, using the configuration and principle of SPM.

However, in these devices, the periodic xy scanning may be different from the raster scanning. For example, in a memory device, a recording medium 1504 as shown in FIG.
When the print data sequence 1506 arranged in a line along the upper track 1505 is scanned at a constant speed in the y direction while periodically scanning in the x direction, or a concentric circle as shown in FIG. Tracks 1 (or spiral)
In some cases, the print data sequence 1602 is scanned in a circular shape along the line 601, that is, xy-direction scanning is performed by a sine wave signal whose phase is shifted by a quarter period.

In the case of scanning the print data sequence shown in FIG. 15A, as shown in FIG. 15B, a true displacement signal 1503 is added to the x-direction scanning signal 1502, and the apparent position is changed. A shift signal 1501 is generated, and the trajectory of the probe scan is as shown by a broken line in FIG. The same signal processing as in FIGS. 7 and 9 is performed on the relative displacement amount in the x direction, and the true displacement signal 1503 is obtained by removing the x-direction scanning signal 1502 component from the apparent displacement signal 1501. The component is obtained, and the relative displacement between the recording medium 1504 and the probe (not shown in FIG. 15) is corrected.

In the case of scanning the print data sequence shown in FIG. 16 (a), as shown in FIGS. 16 (b) and 16 (c), true scan signals 1606 and 1609 are applied to the scan signals 1606 and 1609, respectively. The displacement signals 1605 and 1608 are added to generate apparent displacement signals 1605 and 1608, and the trajectory of the probe scan is as shown by the broken line in FIG. For these, the same signal processing is performed for the relative positional deviation amounts in both the x and y directions, and x and y
It is possible to correct the relative displacement in both directions.

Although the above-described x-direction displacement correction signal processing circuit has the configuration shown in FIGS. 7 and 8, it may be the one shown in FIGS. 9 and 10. At this time, since the frequency of the scanning signal in the x direction is higher than that of the scanning signal in the y direction, an error occurs in the displacement amount sampling signal due to a parasitic vibration caused by a sudden reversal of the driving direction of the x direction driving element at the turning point of scanning. Tends to occur. Therefore, as shown in FIG.
Is desirably a waveform having a smooth curve such as a sine wave signal that does not have a sharp inversion.

In the x-direction scanning signal 17a as shown in Z417 (a), the x-direction relative displacement signal 17b, x
Each of the direction scanning synchronization signal 17c, the x-direction displacement amount sampling signal 17d, and the interpolation signal 17e is shown in FIG.
(B) to (e).

FIG. 17 shows the sampling position.
The error described above does not occur if the position is near the point where the relative position shift speed of the scan turn-back portion becomes 0 as shown in (d).

[0071]

Since the present invention is constructed as described above, it has the following effects.

According to the first to eighth aspects of the present invention, there is provided a scanning probe microscope in which relative displacement between the probe and the sample does not occur during the operation of the apparatus for a long time immediately after the setting of the apparatus. There is an effect that can be.

According to the ninth to eleventh aspects, in addition to the above-mentioned effects, there is an effect that it is possible to prevent erroneous operation of misregistration correction control due to mechanical and electrical noise.

According to the twelfth aspect, in addition to the above-described effects, there is an effect that control can be performed at an optimum control position of the actuator for correcting positional deviation.

According to the thirteenth and fourteenth aspects, there is an effect that a memory device and a lithography device having each of the above effects can be realized.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of one embodiment of the present invention.

FIG. 2 is a top view of the embodiment shown in FIG.

FIG. 3 is a diagram showing a configuration of an apparatus for introducing two-wavelength coherent lights polarized in mutually orthogonal directions into a polarization maintaining fiber.

FIG. 4 is a diagram for explaining raster scanning of a probe in a scanning probe microscope.

FIG. 5 is a diagram for explaining a case where a displacement in the x direction occurs during raster scanning.

FIG. 6 is a diagram for explaining a case where a displacement in the y direction occurs during raster scanning.

FIG. 7 is a diagram for explaining an x-direction position correction signal circuit.

FIG. 8 is a signal waveform diagram in the x-direction position correction signal circuit.

FIG. 9 is a diagram for explaining a y-direction position correction signal circuit.

FIG. 10 is a signal waveform diagram in a y-direction position correction signal circuit.

FIG. 11 is a signal waveform diagram in the estimation circuit.

FIG. 12 is an estimating circuit signal waveform diagram in which a plurality of positional displacement components having different relaxation times are combined.

FIG. 13 is a longitudinal sectional view of a scanning probe microscope apparatus of an embodiment using a heterodyne interference optical system using a fiber.

FIG. 14 is a cross-sectional view of a scanning probe microscope apparatus of an embodiment using a heterodyne interference optical system using a fiber.

FIG. 15 is an explanatory diagram of an example in which the present invention is applied to a memory device.

FIG. 16 is an explanatory diagram of an example in which the present invention is applied to a memory device.

FIG. 17 is a signal waveform diagram of another signal processing method in x-direction position correction.

[Explanation of symbols]

 Reference Signs List 101 sample 102 probe 103 xy drive element 104 mirror A 105 polarization preserving fiber 106 device casing 107 collimator lens 108 beam splitter R 109 polarizing plate R 110 sensor R 111 polarizing beam splitter A 112 phase plate A 113 phase plate A ' 114 Mirror A '115 Polarizer A 116 Sensor A 117 Mirror B' 118 Z drive element 119 xy scan signal circuit 120 xy drive circuit 201, 202, 203 Beam splitter 204 Mirror C 205 Mirror B 206 Mirror D 207 Sensor C 208 Sensor B 209 Sensor D 301 Semiconductor laser 302 Collimator lens 303 First polarizing beam splitter 304 First mirror 305 Second polarizing beam splitter 306 Second mirror 307 Sound Light modulator 308 Condenser lens 309 Polarization preserving fiber 701, 702, 703 Current / voltage conversion circuit 704, 705, 706, 707 Synchronization detection circuit 708 Phase shifter 709, 710, 711, 712 Low-pass filter 713 Counter 714, 715 Binarization circuit 716 Counter 717 Averaging circuit 718 Low-pass filter 719 Subtraction circuit 720 Amplification circuit 721 Signal processing circuit 722 Estimation circuit 901, 902, 903 Current / voltage conversion circuit 904, 905, 906, 907 Synchronization detection circuit 908 Phase shifter 909 , 910, 911, 912 Low pass filter 913 Counter 914, 915, Binarization circuit 916 Counter 917 Averaging circuit 918 Sampling circuit 919 Interpolation circuit 920 Estimation circuit 921 Subtraction circuit 922 amplifying circuit 923 signal processing circuit 1301 sample 1302 probe 1303 xy drive element 1304 z drive element 1305 mirror A 1306 mirror B 1307 fiber fixture A 1308 device housing 1309 polarization preserving fiber A 1310 orthogonal polarization dual wavelength coherent light source 1311 Beam splitter 1312 Polarizing plate 1313 Sensor R 1314 Polarizing beam splitter 1315 Quarter wave plate 1316 Lens 1317 Quarter wave plate 1318 Mirror 1319 Polarizing plate 1320 Sensor A 1321 Polarization preserving fiber B 1322 Fiber fixing tool B 1401 Fiber fixing tool C 1402 Fiber fixture D 1403 Polarization preserving fiber C 1404 Polarization preserving fiber D 1405 Mirror C 1406 Mirror D 1501 Apparent position Displacement signal 1502 x-direction scanning signal 1503 true displacement signal 1504 recording medium 1505 track 1506 recording data sequence 1601 track 1602 recording data sequence 1604 apparent displacement signal 1605 true displacement signal 1606 y-direction scanning signal 1607 apparent 1608 true displacement signal 1609 x-direction scanning signal

──────────────────────────────────────────────────続 き Continuation of front page (72) Inventor Masahiro Tagawa 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (56) References JP-A-3-152845 (JP, A) JP-A Heisei 2-216749 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01B 21/00-21/32 H01J 37/28

Claims (14)

(57) [Claims] 1. A probe arranged such that a tip thereof is opposed to and close to a surface of a sample, and said probe is orthogonal to said facing direction of said sample and is predetermined. Scanning means for scanning relatively to the path taken, and detecting means for detecting a physical quantity generated between the sample and the probe, wherein the scanning means performs scanning based on a detection result of the detecting means. In a scanning probe microscope for observing a sample surface, when scanning the probe, a relative position between the sample and the probe in a direction orthogonal to a facing direction of the sample and the probe is detected, and the detected content is determined. A position shift amount detection unit that outputs a first position shift amount detection signal, and a signal component associated with scanning between the sample and the probe is removed from the first position shift amount detection signal. Output as displacement detection signal That the scanning signal component removing means, said second deviation amount detection signal on the basis of sequentially correcting the positional displacement between the probe and the sample correction means and a scanning probe microscope characterized by having a. 2. The scanning probe microscope according to claim 1, wherein the scanning signal component removing means is a low-pass filter having a cutoff frequency lower than a scanning frequency between the sample and the probe. Probe microscope. 3. The scanning probe microscope according to claim 1, wherein the scanning signal component removing means samples the displacement detection signal at a timing synchronized with the scanning between the sample and the probe. Probe microscope. 4. The scanning probe microscope according to claim 3, wherein the scanning signal component removing means interpolates between sampling points. 5. The scanning probe microscope according to claim 3, wherein the scanning performed by the scanning means is performed by a smooth return signal near the return point, and the scanning signal component removing means performs the scanning. A scanning probe microscope, wherein a sampling operation is performed near the turning point. 6. A scanning probe microscope according to claim 1, wherein the displacement detecting means is a light wave interferometer. 7. The scanning probe microscope according to claim 6, wherein the optical interferometer is one of a mirror fixed to a member for fixing the sample, a mirror fixed to a member for fixing the probe, and a mirror. A means for inputting coherent light to one side, a means for separating a part of the coherent light and changing the optical path to make it incident on the other side of the mirror, and a means for combining the two reflected lights from the mirror based on a combined light intensity signal And a means for calculating a relative movement amount of the mirror. 8. The scanning probe microscope according to claim 6, wherein the light wave interferometer is fixed to one of a member for fixing the sample and a member for fixing the probe, and is fixed to the other, and has an end face. A composite light intensity signal consisting of an optical fiber placed closer to the mirror, a means for causing coherent light to enter the mirror through the optical fiber, and a light reflected by the mirror and passed through the optical fiber again and a part of the coherent light previously separated A scanning probe microscope comprising: an optical fiber interferometer comprising: means for calculating a relative movement amount of a mirror with respect to an end face of the optical fiber based on the optical fiber. 9. The scanning probe microscope according to claim 1, wherein the correcting unit detects the amount of displacement based on the second displacement detection signal output by the scanning signal component removing unit. An estimating circuit for estimating a temporal change of the sample, and a subtraction circuit for correcting a positional deviation between the sample and the probe based on an estimated result of the estimating circuit and a set position corresponding to a predetermined course. Features scanning probe microscope. 10. The scanning probe microscope according to claim 9, wherein the estimating operation in the estimating circuit targets at least one or more positional shift amounts due to relaxation times of different time constants, and the intensity and time constant of these components. A scanning probe microscope characterized by inferring the following. 11. The scanning probe microscope according to claim 9, wherein the estimating circuit estimates an estimated value from the input second displacement amount signal and the second displacement amount signal before the input. Means for outputting an estimated value from the second displacement amount signal before the input without making an estimation based on the input second displacement amount signal when the difference from the second displacement amount signal exceeds a predetermined value. Features scanning probe microscope. 12. The scanning probe microscope according to claim 1, wherein the correction means includes a first actuator and a second actuator that moves including the first actuator. A scanning probe microscope for correcting a displacement between a sample and a probe using each of these actuators. 13. A memory device which performs recording or reading on a recording medium using the configuration of the scanning probe microscope according to claim 1. 14. A lithography apparatus for performing recording on a recording medium using the configuration of the scanning probe microscope according to claim 1. Description: