JP2003307681A - Confocal scanning optical microscope - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a confocal scanning optical microscope which makes it possible to easily and rapidly obtain height information within a range where measurement is necessary. <P>SOLUTION: The microscope is equipped with an objective lens (7) for condensing the light from a light source to a sample (8), a scanning mechanism (3) for relatively scanning the surface of the sample with focusing light along this surface, a moving mechanism for relatively moving the beam-condensing position of the objective lens and the position of the sample along the optical axis of the focusing light, a microaperture (10) arranged in a position conjugate with the beam-condensing position of the objective lens, a photodetector (11) for detecting the intensity of the light passing the microaperture, and control means (12) having a function to determine the height information of the sample in accordance with the output of the photodetector, a function to assign two points of arbitrary ranges or more in a view field, a function to focus the assigned range and a function to determine the range of height measurement in accordance with the position information obtained by the automatic focusing. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for measuring surface information of a sample by scanning the sample with light through an optical system of the optical microscope, and more particularly to a confocal scanning optical microscope.

[0002]

2. Description of the Related Art A confocal scanning optical microscope illuminates a sample in a point shape, collects light from the sample, for example, reflected light on a pinhole, and then outputs the intensity of the light passing through the pinhole. Surface information of the sample is obtained by detecting the

FIG. 3 is a diagram showing a schematic configuration of a general confocal scanning optical microscope. In the confocal scanning optical microscope shown in FIG. 3, the light emitted from the light source 1 passes through the beam splitter 2 and then enters the two-dimensional scanning mechanism 3.
The two-dimensional scanning mechanism 3 including the first optical scanner 3a and the second optical scanner 3b scans the light flux two-dimensionally and guides it to the objective lens 7. The light beam incident on the objective lens 7 becomes convergent light and scans the focal plane of the sample 8. Here, the light reflected on the surface of the sample 8 is again introduced from the objective lens 7 to the beam splitter 2 via the two-dimensional scanning mechanism 3, and then reflected by the beam splitter 2 to form an imaging lens 9
The light is focused on the pinhole 10 by.

The pinhole 10 cuts the reflected light from other than the condensing point of the sample 8, and only the passing light is detected by the photodetector 1.
1 is detected and guided to the computer 12. The sample 8 is placed on the sample table 13, and the Z stage 14
It is possible to move along the optical axis. The two-dimensional scanning mechanism 3 and the Z stage 14 are the computer 12
Controlled by.

Here, the focal point of the objective lens 7 is optically conjugate with the pinhole 10. That is, when the sample 8 is at the position where the objective lens 7 condenses, the reflected light from the sample 8 is condensed on the pinhole 10 and passes through the pinhole 10. Sample 8 is objective lens 7
In the case of a position deviated from the condensing position due to, since the reflected light from the sample 8 is not condensed on the pinhole 10,
Do not pass through the pinhole 10.

Therefore, the objective lens 7 and the sample 8 at this time are
The relationship between the relative position of and the output of the photodetector 11 is as follows. That is, when the sample 8 is at the focus position of the objective lens 7, the output of the photodetector 11 becomes maximum. Then, as the relative position between the objective lens 7 and the sample 8 moves away from this position, the output of the photodetector 11 drops sharply. Therefore, when the focal point is two-dimensionally scanned and the output of the photodetector 11 is imaged in synchronization with the two-dimensional scanning mechanism 3 and displayed on the monitor 15, only a specific height of the sample 8 is imaged. , An image (confocal image) obtained by optically slicing the sample 8 is obtained.

Further, while the sample 8 is discretely moved in the optical axis direction, a confocal image is acquired and the position of the Z stage 14 at which the output of the photodetector 11 is maximized is detected at each point of the sample. Thus, height information of the sample 8 can be obtained. When acquiring the height information of the sample 8 with such a configuration, it is necessary to specify the measurement range, that is, the moving range of the Z stage 14, so that the necessary height information can be obtained. Generally, as a method of designating the measurement range, the Z stage 14 is moved up and down while looking at the confocal image, and the measurement range is manually designated so that at least the position where the image signal of the portion to be measured becomes maximum is included. However, since this method is a manual operation, the operator is burdened and the measurement takes time.

In order to solve the above problems, the applicant has proposed a method of automatically designating a measurement range (Japanese Patent Laid-Open Nos. 6-308393 and 8-2784).
No. 50). In this proposal, the Z range 14 is discretely moved while the confocal image signal is acquired, and the measurement range is determined by devising a threshold value for the intensity of the image signal.

However, in the above proposal, when the Z stage 14 is discretely moved while acquiring the confocal image, it is necessary to acquire the confocal image at each position, so that it takes a long time to perform the measurement. Will end up. In addition, when there is a large step in a range unnecessary for measurement in the image range, the unnecessary range is also designated as the measurement range. Therefore, the measurement may unnecessarily take time.

Further, the present applicant has proposed a method for automatically focusing on an arbitrary position within the visual field (Japanese Patent Laid-Open No. 2000-3).
9562). This proposal discloses a method of determining a step between two points by designating any two points. However, according to this proposal, although height difference can be measured, height information including a shape cannot be obtained because height information other than the designated point cannot be obtained.

[0011]

DISCLOSURE OF THE INVENTION The present invention provides a confocal scanning optical microscope capable of easily and rapidly acquiring height information in a range required for measurement in measuring the height of a sample. The purpose is to

[0012]

The present invention has taken the following means in order to solve the above problems.

A confocal microscope according to one aspect of the present invention includes an objective lens that focuses light from a light source onto a sample, and a scanning mechanism that relatively scans the focused light along the surface of the sample. A moving mechanism for relatively moving the focusing position of the objective lens and the position of the sample along the optical axis direction of the focused light, and a microscopic device arranged at a position conjugate with the focusing position of the objective lens. An aperture, a photodetector for detecting the intensity of light passing through the minute aperture, a height information acquisition function for obtaining height information of the sample based on the output of the photodetector, and 2 in one visual field. A range specification function for specifying an arbitrary range of points or more, an automatic focusing function for focusing on each specified range, and a height measurement based on position information obtained from the automatic focusing function. With the height measurement range determination function to determine the range, Characterized by comprising control means for, the.

According to this aspect, first, the range designation function is used to designate an arbitrary range that needs to be measured in the image field based on the confocal image. Next, with the automatic focusing function,
Focusing processing is performed for each range designated by the range designating function, and the focus position is passed to the height measurement range determining function. The height measurement range function obtains the maximum value and the minimum value of those position coordinates from the in-focus position information and adds a predetermined range to them to determine the height measurement range. Height measurement is performed according to this measurement range.

As a result, the height can be measured automatically and only in the required height range by simply designating the position in the visual field where the height measurement is desired, and the height can be measured easily and at high speed.

A preferred embodiment of the above confocal scanning optical microscope is as follows. The following embodiments may be applied individually or in appropriate combination. (1) It further comprises a non-confocal image acquisition means for obtaining a non-confocal image without the fine aperture or a microscope image acquisition means for obtaining a normal microscope image, and the range designation function is a non-confocal point. Designate an arbitrary range of two or more points in one visual field based on an image or a TV image. Non-confocal images and TV images have a deeper depth of focus than confocal images. Therefore, the work becomes easier when designating the measurement position.

(2) The range designation function registers the designated range information, and the height measurement range determination function determines the height measurement range based on the registered range information. By registering the range information specified in the range specifying function, it is possible to use the position information created in the past or the position information prepared in advance. Therefore, it becomes possible to perform the measurement easily and at high speed when the same work is repeated or when the automatic measurement is performed.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described with reference to the drawings.

(First Embodiment) FIG. 1 is a schematic configuration diagram of a confocal scanning optical microscope according to the first embodiment.
In FIG. 1, the same parts as those in FIG. 3 are designated by the same reference numerals.

In the confocal scanning optical microscope shown in FIG. 1, the light emitted from the light source 1 enters the two-dimensional scanning mechanism 3 after passing through the beam splitter 2. The two-dimensional scanning mechanism 3 includes a first optical scanner 3a and a second optical scanner 3b. Galvano scanners are used as the first and second optical scanners 3a and 3b, and by controlling the swing angle of these by the computer 12, the converged light can be positioned at an arbitrary position on the sample. it can. In this way, the two-dimensional scanning mechanism 3 two-dimensionally scans the light flux that has passed through the beam splitter 2.
This light flux is guided to the objective lens 7. Objective lens 7
The light beam incident on becomes a convergent light and scans the surface of the sample 8. The light reflected by the surface of the sample 8 is introduced into the beam splitter 2 via the optical path opposite to the incident light, that is, from the objective lens 7 through the two-dimensional scanning mechanism 3. Then, the reflected light is reflected by the beam splitter 2, the optical axis is changed, and is condensed on the pinhole 10 by the imaging lens 9.

Of the reflected light from the sample 8, the reflected light from other than the condensing point is cut by the pinhole 10, and only the light passing through the pinhole 10 is detected by the photodetector 11. The sample 8 is placed on the sample table 13 and can be moved in the optical axis direction by the Z stage 14. The two-dimensional scanning mechanism 3, the Z stage 14 and the photodetector 11 are controlled by the computer 12.

Here, the focusing position by the objective lens 7 is
The position is optically conjugate with the pinhole 10. As a result, when the sample 8 is at the position where the objective lens 7 condenses, the reflected light from the sample 8 is condensed on the pinhole 10 and passes through the pinhole 10. On the other hand, when the sample 8 is located at a position deviated from the focusing position by the objective lens 7, the reflected light from the sample 8 is not focused on the pinhole 10 and does not pass through the pinhole 10.

Therefore, the relationship between the relative position of the objective lens 7 and the sample 8 and the output of the photodetector 11 is that the sample 8 is the objective lens 7
The output of the photodetector 11 is maximized when it is located at the light collecting position. Here, as the relative position between the objective lens 7 and the sample 8 moves away from this position, the output of the photodetector 11 drops sharply.

Using this characteristic, the computer 12
The condensing point is two-dimensionally scanned by the two-dimensional scanning mechanism 3, the output of the photodetector 11 is imaged in synchronization with the two-dimensional scanning mechanism 3, and the image is displayed on the monitor 15. Only the image is imaged, and an image (confocal image) obtained by optically slicing the sample 8 is obtained. Further, the sample 8 is discretely moved in the optical axis direction by using the Z stage 14, the two-dimensional scanning mechanism 3 is scanned at each position to acquire a confocal image, and the photodetector 11 of each point of the sample is scanned. The height information of the sample 8 can be obtained by detecting the position of the Z stage 14 that maximizes the output.

The computer 12 is also provided with a one-field-of-view range specifying unit 18 and a height measurement range determining unit 19. Based on the confocal image displayed on the monitor 15, the one-field-of-view range designation unit 18 sets the coordinates (for example, the range 17 shown in the figure) of an arbitrary range on the image instructed by the operation unit 16.
Specify more than one place. The designated range is registered in the one-field-of-view range designation unit 18.

When registration of the designated range in the one-field-of-view range designation section 18 is completed, first, the first and second light beams are scanned so as to scan or stop at the coordinate position of the first registered coordinate range. The scanners 3a and 3b are controlled. Next, the Z stage 14 is moved up and down, and the coordinate of the position where the output from the photodetector 11 is maximized is set as the in-focus position, and the height measurement range determination unit 1
Register at 9. This operation is executed for all designated ranges registered in the one-field-of-view range designation section 18. next,
The height measurement range determination unit 19 compares the registered in-focus position coordinates to obtain the maximum value and the minimum value. further,
The height measurement range is determined by adding predetermined values in the upward and downward directions (that is, the Z direction) of the range given by the maximum value and the minimum value. Here, the predetermined value is determined in consideration of the accuracy of the Z stage 14 and the S / N of the photodetector 11. Then, finally, based on the height measurement range thus determined, the confocal image is acquired efficiently while discretely moving the Z stage 14, so that the necessary range is reduced to the minimum. It is possible to obtain the height information of the included sample 8.

(Second Embodiment) FIG. 2 is a schematic configuration diagram of a confocal scanning optical microscope according to the second embodiment.
2, the same parts as those in FIG. 1 are designated by the same reference numerals, and detailed description thereof will be omitted.

The confocal scanning optical microscope shown in FIG. 2 is different from the configuration of the confocal scanning optical microscope shown in FIG. 1 in that the light partially led out between the beam splitter-2 and the imaging lens 9. It comprises a non-confocal optical path 20 having no pinhole on the road and a photodetector 21.

The beam splitter as described above
As a method of deriving a part of the optical path between the optical path 2 and the imaging lens 9, generally, an optical path splitting element such as a half mirror, a dichroic mirror, or a beam splitter is provided on the optical path, or total reflection is performed on the optical path. It is conceivable that the mirror can be inserted and removed freely.

The other structure is the same as that of FIG.

In the above structure, the photodetector 21
If the output of is imaged on the monitor 15, an image with a deep depth of focus similar to that of an ordinary optical microscope can be obtained. Therefore, the second
In the above embodiment, a non-confocal image is used when designating a range within one visual field. This makes it possible to more easily perform the work of designating the range within one visual field. The same effect can be obtained by using a TV image instead of the non-confocal optical path and using a TV image.

The present invention is not limited to the above embodiments of the invention. For example, in the first and second embodiments, the one-field-of-view range specifying unit 18 has a storage device (not shown) for storing and reading the registered coordinate range. Thereby, when the same sample is repeatedly measured, it is not necessary to specify the range, and the measurement is further facilitated. Furthermore, it is possible to eliminate the need to manually specify a category by reading a value that is determined in advance by a design value or the like. Further, the control method of the confocal operation type optical microscope described in the above embodiment,
The program itself can be used as a control program, and what is recorded in another host computer via a recording medium or a communication line can be read by the control device of the confocal scanning optical microscope. The same control can be enabled. Of course, various modifications can be made without departing from the scope of the present invention.

[0033]

As described in detail above, according to the present invention,
In measuring the height of a sample, it is possible to provide a confocal scanning optical microscope that can easily and rapidly perform height information of a range that requires measurement.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a confocal scanning optical microscope according to a first embodiment.

FIG. 2 is a schematic configuration diagram of a confocal scanning optical microscope according to a second embodiment.

FIG. 3 is a diagram showing a schematic configuration of a general confocal scanning optical microscope.

[Explanation of symbols]

1 ... Light source 2 ... Beam splitter Three-dimensional scanning mechanism 3a ... the first optical scanner 3b ... second optical scanner 3a. 3b ... second optical scanner 7 ... Objective lens 8 ... Sample 9 ... Imaging lens 10 ... Pinhole 11 ... Photodetector 12 ... Computer 13 ... Sample stand 14 ... Z stage 15 ... Monitor 16 ... Operation unit 18 ... Range designation part within one field of view 19 ... Measuring range determination unit 20 ... Non-confocal optical path 21 ... Photodetector

Claims (3)

[Claims] 1. An objective lens for focusing light from a light source on a sample, a scanning mechanism for relatively scanning the focused light along the surface of the sample, and an optical axis direction of the focused light. And a moving mechanism that relatively moves the focusing position of the objective lens and the position of the sample, a minute opening arranged at a position conjugate with the focusing position of the objective lens, and the minute opening. A photodetector that detects the intensity of light, a height information acquisition function that obtains height information of the sample based on the output of the photodetector, and a range designation that designates an arbitrary range of two or more points in one visual field Function, automatic focusing function for focusing on each designated range, and height measurement range determination function for determining the range of height measurement based on the position information obtained from the automatic focusing function And a control means having Confocal scanning optical microscope according to claim. 2. The confocal scanning optical microscope according to claim 1, wherein a non-confocal image acquisition means for obtaining a non-confocal image without the fine aperture or a microscope image for obtaining a normal microscope image. A confocal scanning optical microscope, further comprising an acquisition unit, wherein the range designating function designates an arbitrary range of two or more points in one visual field based on a non-confocal image or a TV image. . 3. The confocal scanning optical microscope according to claim 1 or 2, wherein the range designation function registers designated range information, and the height measurement range determination function comprises:
A confocal scanning optical microscope, characterized in that a height measurement range is determined based on the registered range information.