JP2724502B2 - Scanning microscope equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to a scanning microscope apparatus.

(Prior art) Conventionally, as a microscope device having a high resolution, a light beam converged in a minute spot shape is two-dimensionally deflected to scan a sample at high speed, and reflected light or transmitted light from the sample is converted into an electric signal. Scanning microscope devices that convert and obtain an image of a sample have been put to practical use.

FIG. 20 shows a configuration of an example of such a conventional scanning microscope apparatus. A light beam 2 from a light source, for example, a laser light source 1 passes through a relay lens 3 and a half mirror 4, and
The light is deflected in a two-dimensional direction by the vibrating mirror X5 and the vibrating mirror Y6, condensed by the objective lens 7, and irradiated onto the sample 8. The reflected light 9 from the sample 8 is transmitted to the objective lens 7, the vibration mirror Y6, the vibration mirror X5, the half mirror 4,
It follows the same path as the illumination beam, but reversely, through an aperture 10 to a detector, for example a photomultiplier 11. The electric signal photoelectrically converted by the photomultiplier 11 is processed to obtain an image of the sample.

In the conventional scanning microscope apparatus having the above-described configuration, as shown by a dotted line in the figure, stray light (reflected light from an undesired portion) generated by lens aberration or the like is blocked by the aperture 10 and enters the photomultiplier 11. Not configured. That is, only the reflected light from the desired portion (the portion irradiated with the light beam 2) of the sample 8 is exposed to the photomultiplier 11.
, A so-called pinhole effect is realized, and an image with high resolution that is not affected by stray light can be obtained.

However, in such a conventional scanning microscope apparatus, it takes time to scan and detect a light beam, and for example, 25
To display an image on a 6 x 256 pixel monitor, one screen
There is a problem that it takes about 65 seconds. Further, although the positional accuracy between pixels depends on the accuracy of the two-dimensional deflecting device, it is difficult to maintain high accuracy of the deflecting angle of the deflecting device, so that there is a problem that an image displayed on a monitor is distorted. Was.

For example, in Japanese Patent Application Laid-Open No. 61-80215, in order to enable high-speed scanning and detection of a light beam, for example, an acousto-optic deflecting element is used as a deflecting element for scanning a light beam, and a one-dimensional image is used as a photoelectric conversion means. Devices using sensors have been proposed. That is, this device can detect signals on the one-dimensional image sensor collectively,
A great improvement in the speed can be realized as compared with the above-described device.

(Problems to be Solved by the Invention) However, in the above-described device using the conventional one-dimensional image sensor, the pinhole effect in the one-dimensional direction among the two-dimensional images displayed on the monitor cannot be realized.
That is, there is a problem in that the resolution is reduced due to the influence of stray light between adjacent photoelectric conversion elements on the one-dimensional image sensor.

In addition, since the positions of the photoelectric conversion elements on the one-dimensional image sensor are constant, one-dimensional image distortion of the two-dimensional image displayed on the monitor is corrected by the positions of these photoelectric conversion elements. However, the direction orthogonal to this depends on the accuracy of the deflection angle of the deflecting means, and there is still a problem that image distortion still occurs.

The present invention has been made in view of such a conventional situation, and has as its object to provide a scanning microscope apparatus capable of performing high-speed display with little reduction in resolution and image distortion due to the influence of stray light. is there.

[Means for Solving the Problems] That is, according to the present invention, a sample is scanned and irradiated with a light beam, and reflected light or transmitted light from the sample is converted into an electric signal by a light receiving means. In the scanning microscope apparatus which obtains an image of the sample by processing the image, the light receiving means is an image in which a plurality of photoelectric conversion elements for converting reflected light or transmitted light from the sample into an electric signal are arranged at least one-dimensionally. An AOM for turning on / off the light beam and an AOD for scanning the light beam, the light beam is formed by one or more of the photoelectric conversion elements arranged one-dimensionally in a plurality in a one-dimensional manner. While selectively scanning and irradiating a sample area intermittently set in advance so as to correspond to every other photoelectric conversion element, the photoelectric conversion element corresponding to the irradiation position of this light beam Intermittent image information is obtained by extracting only signals from
The apparatus is characterized in that an image of the sample is obtained by synthesizing a plurality of intermittent image information obtained by performing these scans a plurality of times.

(Operation) In the scanning microscope apparatus of the present invention, a light beam is selectively scanned and radiated to a preset sample region. Intermittent image information is obtained by extracting only a signal from a light receiving unit, for example, a light receiving element corresponding to the irradiation position of the light beam among a large number of photoelectric conversion elements of a one-dimensional image sensor or a two-dimensional image sensor. Then, an image of the sample is obtained by synthesizing a plurality of intermittent image information obtained by performing these scans a plurality of times.

Therefore, for example, even if stray light affecting adjacent light receiving elements is generated, image display with high resolution and less image distortion can be performed at high speed without being affected by the stray light.

(Example) Hereinafter, an example of a scanning microscope apparatus of the present invention will be described with reference to the drawings.

First, an embodiment using a one-dimensional image sensor will be described.

As shown in FIG. 1, in the scanning microscope apparatus of this embodiment, the light beam 22 from a light source, for example, a laser light source 21 passes through a collimating lens 23 to an AOD 24 as means for scanning the light beam 22 at high speed, for example, in the X direction. Incident, from the AOD 24 to a vibrating mirror 27 as a means for scanning the light beam 22 in, for example, the X direction through a relay lens 25 and a half mirror 26,
The sample 29 is scanned and irradiated from the vibration mirror 27 through the objective lens 28. The reflected light 30 from the sample 29 passes through the objective lens 28, the vibrating mirror 27, and the half mirror 26, and is incident on a one-dimensional image sensor 31 in which a large number of photoelectric conversion elements are arranged in a line. .

The image signal photoelectrically converted by the one-dimensional image sensor 31 is input to the image signal processing unit 32, and an image of the sample 29 is obtained as follows.

That is, as shown as a hatched area in FIG. 2A, the scanning of the sample 29 with the light beam 22 is performed in the direction (X direction) corresponding to the photoelectric conversion element row of the one-dimensional image sensor 31.
Is performed by AOD24 which can scan at high speed, and a vibration mirror is used in the direction (Y direction) orthogonal to this direction.
Perform by 27.

First, as shown in FIG. 2 (B), scanning irradiation of the light beam 22 by the AOD 24 is performed, for example, on one of the photoelectric conversion element rows.
A predetermined interval is provided so as to correspond to every other step, and the stepwise operation is performed.
Of the image signals of the three-dimensional image sensor 31, for example, only every other signal (shown by oblique lines in the figure) of the photoelectric conversion element array corresponding to the irradiation area of the light beam 22 is selected and taken in, and the intermittent image information 31a is obtained. Get. That is, at this time, a signal corresponding to stray light is generated from the photoelectric conversion element of the one-dimensional image sensor 31 corresponding to a region not hatched in the drawing.
Without using these signals, only the signals corresponding to the irradiation area of the light beam 22 are selected.

Next, as shown in FIG. 2 (C), at the same Y-direction position, a position corresponding to a region where no signal is taken in the above operation (a region not hatched in FIG. 2 (B)) Scanning irradiation of the light beam 22 by the AOD 24 and capturing of signals are performed, and intermittent image information 31b corresponding to these regions is obtained.

Thereafter, as shown in FIG. 2 (D), every other signal of the photoelectric conversion element array of the one-dimensional image sensor 31 obtained by scanning and irradiating the light beam 22 twice with the AOD 24 in the X direction, that is, as shown in FIG. The intermittent image information 31a and 31b are combined, and the one-dimensional image information 31 in the X direction at a predetermined Y direction position is synthesized.
get c.

Then, the above operation is repeated while moving the Y-direction position at a predetermined interval by the vibration mirror 27, thereby obtaining the sample 29.
Is obtained.

Therefore, in the scanning microscope apparatus of this embodiment, 1
Crosstalk due to stray light between adjacent photoelectric conversion elements of the three-dimensional image sensor 31 can be prevented, and image display with high resolution and less image distortion can be performed. Image distortion due to the scanning accuracy of the vibrating mirror 27 remains). Also, in order to obtain the one-dimensional image information 31c, two scanning irradiations of the light beam 22 by the AOD 24 must be performed at the same Y-direction position. However, the AOD 24 can perform high-speed scanning, so that the AOD 24 is sufficiently fast. Display can be performed. Further, since only one AOD 24 is used, an increase in manufacturing cost can be minimized as compared with a conventional scanning microscope apparatus.

In the above embodiment, the case where the scanning irradiation of the light beam 22 and the capture of the signal are performed so as to correspond to every other photoelectric conversion element of the one-dimensional image sensor 31 has been described. As shown in (D), the scanning and irradiation of the light beam 22 is performed so as to correspond to every third photoelectric conversion element of the one-dimensional image sensor 31, and the corresponding image information 31e, 31f, and 31g are synthesized and 1 The configuration may be such that the three-dimensional image information 31h is obtained, or three or more may be obtained. In this case, the possibility of being affected by stray light decreases as the interval is set to every third or third, etc., but it is necessary to substantially improve the resolving power even if the interval is set longer than necessary due to the conditions of the optical system. Cannot be performed, and conversely, it takes time to display an image. For this reason, the interval at which the scanning irradiation of the light beam 22 and the capture of the signal are performed as described above is
It is necessary to select an appropriate value depending on the conditions of the optical system.

By the way, in the scanning microscope apparatus of the above embodiment, the fourth
As shown by the solid line in the graph in the figure, the deflection angle of the AOD 24 is changed in a step-like manner, and the scanning irradiation of the light beam 22 is intended to be selectively performed in a step-like manner in response to this. In fact, when scanning at a high speed, the deflection angle of the AOD 24 does not change in a step-like manner as shown by the dotted line in the figure, so that it is substantially the same as in the case of sweeping continuously,
There is a possibility that selective irradiation of the light beam 22 cannot be performed.

Therefore, as shown in FIG. 5, an element capable of performing an ON / OFF operation at a higher speed as compared with the AOD 24, for example, an AOM for modulating the intensity of a light beam is combined, and for example, a discrete as shown in the graph of FIG. In addition, it is possible to control a step-like deflection angle. That is, in this case, as shown in FIG. 7, for example, the AOM 33 is inserted before the AOD 24, and the AOM 33 is turned on / off so as to synchronize with the change in the deflection angle of the AOD 24. With this configuration, selective irradiation of the light beam 22 can be reliably performed. The AOD 24 has a characteristic that the light beam transmission efficiency changes depending on the deflection angle. Therefore, for each deflection angle of the AOD 24, by controlling the intensity modulation of the AOM 33 according to the beam transmission efficiency at the deflection angle, the light beam 22 is irradiated with uniform light intensity in the entire scanning area of the sample 29. You can also.

In addition, in the scanning microscope apparatus of these Examples,
Although the image is obtained by the reflected light from the light source 29, the transmitted light may be detected as in a scanning microscope device shown in FIG. 8 or a scanning microscope device shown in FIG. 9, for example.

That is, in the scanning microscope apparatus shown in FIG. 8, the light beam 22 from the laser light source 21 is directed in a direction perpendicular to the direction of arrangement of the photoelectric conversion elements of the one-dimensional image sensor 31 (the above-described Y direction).
The vibration mirror 27a and the objective lens 2
8a is provided. By vibrating the vibrating mirror 27a in synchronization with the vibrating mirror 27, the light beam 22 transmitted through the sample 29 is incident on the one-dimensional image sensor 31, and the transmitted light is used in the same manner as in the above-described embodiment. To get an image.

On the other hand, the scanning microscope device shown in FIG. 9 uses a vibrating mirror 27b having mirror surfaces on both sides as a means for scanning the light beam 22 from the laser light source 21 in the above-described Y direction.
9, the light beam 22 transmitted through the objective lens 28a is guided to the back side of the vibration mirror 27b by the fixed mirrors 40a, 40b, and 40c.
The one-dimensional image sensor 31 is configured to be reflected on the back surface side of the vibration mirror 27b and incident on the one-dimensional image sensor 31.

Further, for example, a plurality of laser light sources 21a, 21b, AOMs 23a, 23
b, AODs 24a, 24b and half mirrors 26a, 26b can be used to colorize the image. In this case AOM23a, 23
b selects one of the laser light sources 21a and 21b, and irradiates one of the light beams 22a and 22b in a time-division manner.
In this case, as shown in FIG.
It is possible to use one AOD 24 commonly for a and 22b. However, since the deflection angle of the light beam of the AOD 24 changes depending on the wavelength of the light beam, it is necessary to correct the deviation of the deflection angle.

Next, an embodiment using a two-dimensional image sensor will be described.

As shown in FIG. 12, in the scanning microscope apparatus of this embodiment, a light beam 122 from a light source, for example, a laser light source 121,
For example, the light beam 122 passes through the collimator lens 123 in the X direction.
Is incident on AOD124a as a means for high-speed scanning,
The light beam 122 enters the AOD 124b as a means for performing high-speed scanning in the Y direction, for example, in the Y direction from the relay lens 125a through the relay lens 125a. The light beam 122 is transmitted from the AOD 124b to the relay lens 12
The sample 129 is configured to scan and irradiate the sample 129 through the half mirror 5b, the half mirror 126, and the objective lens 128. On the other hand, sample 129
Reflected light 130 from the objective lens 128 and the half mirror 126
Through which a large number of photoelectric conversion elements are arranged two-dimensionally.
It is configured to be incident on the dimensional image sensor 131.

The image signal photoelectrically converted by the two-dimensional image sensor 131 is input to the image signal processing unit 132, and an image of the sample 129 is obtained as follows.

That is, the control of the deflection angles of the AODs 124a and 124b in the X and Y directions is performed by the laser scanning control unit 140.
The scanning irradiation of the light beam 122 on the sample 129 is performed, for example, in the thirteenth
As shown as hatched areas in FIGS.
This is performed selectively and discretely at predetermined intervals in the direction. Then, as in the case of using the one-dimensional image sensor 31 described above, the image signal processing unit 132 includes a photoelectric conversion element corresponding to a portion irradiated with the light beam 122 in the input image signal from the two-dimensional image sensor 131. , And intermittent image information 129a to 129c as shown by shaded areas in FIGS. 13 to 15 are obtained. Then, the same selective scanning irradiation of the light beam 122 and the selective capture of the signal corresponding to the irradiated region are performed for the region other than the hatched region, and these are combined to obtain an image of the sample 129, and a display device such as a CRT 150 To be displayed.

Therefore, in the scanning microscope apparatus of this embodiment, 2
Crosstalk due to stray light between adjacent photoelectric conversion elements of the three-dimensional image sensor 131 can be prevented, and image display with high resolution and less image distortion can be performed. Further, the scanning and irradiation of the light beam 122 must be performed a plurality of times to obtain image information of one screen. However, since the AODs 124a and 124b can perform high-speed scanning, a sufficiently high-speed display can be performed. it can.

As described above, in the scanning microscope apparatus using the two-dimensional image sensor 131 as well, in order to perform selective irradiation of the light beam 122 more reliably as in the above-described embodiment, as shown in FIG. AOM133 and relay lens 125
It is also possible to arrange c so that AOM133 is turned ON / OFF.

As described above, the AODs 124a and 124b have a characteristic that the transmission efficiency changes depending on the deflection angle. Therefore, in the scanning microscope apparatus shown in FIG. 16, a part of the light beam 122 from the laser
It is configured to irradiate the light beam 122 with a uniform light intensity over the entire scanning region of the sample 129 by measuring the intensity and controlling the intensity modulation of the AOM 133. In this case, the intensity of the light beam 122 is monitored for each scan, and the measurement signal is fed back to control the intensity modulation of the AOM 133.
The intensity of the AOM 133 can be monitored and stored in a memory to control the intensity modulation of the AOM 133.

In this way, the light beam 122 is divided into the AOM 133 and the two AODs.
In a scanning microscope apparatus that performs two-dimensional scanning by using 124a and 124b and selectively irradiates, the laser scanning control unit 140 and the image processing unit 132 can be configured as shown in FIG. 17, for example.

That is, in the laser scanning control unit 140, the light beam 1
To selectively and accurately irradiate sample 129 with 22, AOD12
Instead of giving continuous signals to the 4a and 124b by a sweep generator or the like, discrete control by digital values is required.

For this reason, the values obtained by the laser sweep counter 141 are orthogonalized by the DA converters 142a and 142b, respectively.
It is converted into an instruction voltage value corresponding to the deflection angle of the axis with respect to the AODs 124a and 124b. Then, these command voltage values are converted into frequencies by the VF converters 143a and 143b, and the AODs 124a and 124b
Control. At this time, the indicated voltage values are corrected by the correction circuits 144a and 144b so that the deflection angles of the AODs 124a and 124b become linear. Note that the laser sweep direction is the two-dimensional image sensor 13
If an interline transfer type is used, it does not depend on the direction in which the photoelectric conversion element is pulled out.

The selective irradiation of the light beam 122 is performed by the laser sweep counter 141.
Is determined by using the comparator 145 to determine whether or not the light beam 122 is irradiated. Also at this time
The correction circuit 144c corrects the VF converter 143c of the AOM 133 to correct the difference in transmittance due to the deflection angles of the AODs 124a and 124b so that the irradiation intensity of the light beam 122 on the sample 129 is uniform. So that

Further, the image processing unit 132 operates in synchronization with the laser scanning control unit 140 based on a signal from the sequence control circuit 170. However, when using an interline type CCD element, the vertical CCD
Therefore, data delayed by one frame period with respect to the data being scanned by the laser scanning control unit 140 is input.

After the output from the two-dimensional image sensor 131 is shaped by the amplifier 171 into the input level of the A / D converter 172,
The data is converted into data of the frame memory 173 by -D conversion. This data is stored in the frame memory address counter 17
The data is written to the frame memory 173 at the address indicated by 4. At this time, the data not irradiated with the laser is not written into the frame memory 173 only by incrementing the value of the frame memory address counter 174.

In this way, the sample 129 is changed several times while changing the irradiation position.
The image information for one image obtained by scanning and irradiating is read out by the display circuit 175 and displayed on the CRT 150.

As described above, in the scanning microscope apparatus using the two-dimensional image sensor 131, for example, as shown in FIG. 18, a plurality of, for example, three laser light sources 121a to 121c, three collimator lenses 123a to 123c, and three AOM 133a to 133c, 3
Two relay lenses 125d to 125f, three half mirrors 126b
Using three light beams 122a to 122d having different wavelengths.
1c image sensor configured to irradiate 2c
Image colorization can be performed in the same manner as in a scanning microscope device using 31.

When the image is colored in this way, for example, as shown in FIG. 19, light is separated by half mirrors 126e and 126f, and reflected light from the sample 129 is reflected by three two-dimensional image sensors 131a to 131c. It can also be configured to detect.

The present invention may be applied to an optical prober or optical annealing for measuring photovoltaic power generated by irradiating a semiconductor wafer with laser light.

[Effects of the Invention] As described above, according to the scanning microscope apparatus of the present invention, high-speed display can be performed with little reduction in resolution and image distortion due to the influence of stray light.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a scanning microscope apparatus according to an embodiment using a one-dimensional image sensor of the present invention, FIG. 2 and FIG.
FIG. 4 is a diagram for explaining the operation of the scanning microscope apparatus of FIG. 1, FIG. 4 is a graph showing the relationship between the deflection angle of AOD and time,
FIG. 5 is a graph for explaining ON / OFF operation of AOM, FIG. 6 is a graph showing a relationship between deflection angle and time when AOD and AOM are combined, and FIGS. 7 to 11 are one-dimensional. FIG. 12 is a diagram showing a configuration of a scanning microscope device of another embodiment using an image sensor, FIG. 12 is a diagram showing a configuration of a scanning microscope device of an embodiment using a two-dimensional image sensor, and FIGS. Figure 12
Diagram for explaining the operation of the scanning microscope apparatus shown in the figure,
FIG. 16 is a diagram showing a configuration of a scanning microscope device of another embodiment using a two-dimensional image sensor, FIG. 17 is a diagram showing a main portion configuration of the scanning microscope device shown in FIG. 16, and FIG. 19 to 19 are diagrams showing a configuration of a scanning microscope device of another embodiment using a two-dimensional image sensor, and FIG. 20 is a diagram showing a configuration of a conventional scanning microscope device. 21 ... Laser light source, 22 ... Light beam, 23 ... Collimate lens, 24 ... AOD, 25 ... Relay lens, 26 ... Half mirror, 27 ... Vibrating mirror, 28 ... Objective lens, 29 ...
... Sample, 30 ... Reflected light, 31 ... One-dimensional image sensor,
32 ... Image processing unit.

Claims (1)

(57) [Claims] 1. A scanning microscope apparatus which scans and irradiates a sample with a light beam, converts reflected light or transmitted light from the sample into an electric signal by a light receiving means, and processes the electric signal to obtain an image of the sample. In the above, the light receiving means is constituted by an image sensor having at least one-dimensionally arranged photoelectric conversion elements for converting reflected light or transmitted light from a sample into an electric signal, and turns on / off the light beam. The AOM and the AOD scanning the light beam intermittently cause the light beam to intermittently correspond to one or every other photoelectric conversion element among the one-dimensionally arranged photoelectric conversion elements. Intermittent image information is obtained by selectively scanning and irradiating a predetermined sample area and extracting only a signal from the photoelectric conversion element corresponding to the light beam irradiation position. The resulting scanning microscope apparatus characterized by being configured to obtain an image of the sample by synthesizing a plurality of intermittent image information obtained by a plurality of times the scanning.