JPH07306135A - Spectroscope device - Google Patents

Abstract

PURPOSE:To provide a spectroscope device in which a sample can be positioned at the focal point of a focused laser beam or its vicinity and which can be improved in measurement accuracy. CONSTITUTION:Laser light from a light source 1 is commonly used as a laser beam for Raman analysis and reference light for focusing. The focused laser light is projected onto a sample 6 through a prescribed optical system 4 and objective lens 5 and, as a result, irradiates the sample 6. Part of Raman scattered light generated by the sample reaches a pinhole plate 21 positioned to the focal point of a condenser lens 20 through a second half mirror 9 and the lens 20. An optical sensor 22 is provided above the pinhole plate 21. Since all of the light converged to the pinhole plate 21 passes through the plate 21 when the lens 20 is focused on the plate 21, the received light intensity of the photosensor 22 becomes the maximum. Therefore, a CPU 26 moves the objective lens 20 and a Z-stage upward or downward by operating each driving device 5a and 82 so that the received light intensity can become the maximum.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spectroscopic device. More specifically, the measuring light in a spectroscopic device such as a Raman spectroscopic device or an infrared spectroscopic device is focused on a predetermined position on a sample. It relates to improvement of an autofocus mechanism for irradiation.

[0002]

2. Description of the Related Art A spectroscopic device (Raman spectroscopic device) irradiates a sample with laser light and analyzes the Raman scattered light generated from the sample with a spectroscope to determine the surface condition of the sample (for example, on a wafer or IC). It is possible to detect a defect state such as distortion in a minute portion of the) and identify a substance. When irradiating the sample with the laser light, the laser light is condensed by a lens (condensing optical system) and then irradiated. Therefore, ideally, by arranging the sample on the focal position of the lens, it becomes possible to form a beautiful image by maintaining such a positional relationship, and accurate measurement can be performed.

Further, in the actual measurement, the Raman scattered light generated is successively obtained by successively irradiating the laser light onto a predetermined plane area, rather than performing it on only one point of the sample. It is designed to measure. The plane movement can be performed, for example, by placing the sample on an XY stage and moving the XY stage in a predetermined direction.

[0004]

As described above, it is desirable to arrange the sample, more specifically, the irradiation position of the laser beam at the focal position of the lens, but in reality, the inclination of the sample itself and the stage The tilt may cause the laser light to be out of focus on the sample. In such a case, the image is blurred without being formed. Therefore, the Raman light from the sample cannot be formed on the slit of the spectroscope, and the Raman light is apparently weak. Therefore, even on the same sample on a flat surface (without distortion, etc.), the irradiation energy varies depending on the position where the laser beam is irradiated, and the generated Raman light also varies, making accurate measurement impossible. Moreover, the intensity of the generated Raman light may become too weak to be detected. Further, when the surface is not flat, it is necessary to focus according to the unevenness of the surface, and the above problem becomes more remarkable.

The present invention has been made in view of the above-mentioned background, and an object thereof is to allow a sample to be placed almost at the focus of condensed light so that the sample is focused (autofocusing is performed). ) The position of the light to illuminate
Accurate position (focus) can be adjusted by setting the actual measurement position at the same position, and a part of the light used for measurement can be used for the light for position (focus) adjustment. It is possible to perform alignment and measurement in real time, and to measure a position at a depth (inside) from the surface of the sample to a certain depth. The amount and direction can be easily detected, focusing can be performed in a short time, the measurement accuracy can be improved, and the simple configuration and measurement principle can be used to make various judgments. In principle, it is possible to provide a spectroscopic device that can be processed by a comparison process such that the light intensity is large and / or equal, can be processed with a simple configuration, and can simplify the device and further increase the speed. That.

[0006]

In order to achieve the above-mentioned object, in a spectroscopic device according to the present invention, predetermined light is condensed through a condensing optical system and irradiated onto a sample, and based on the irradiation. In the spectroscopic device that performs an analysis process by injecting the return light generated from the sample into the spectroscope, a driving unit that changes the distance between the condensing optical system and the sample and the condensing optical system are used. Means for irradiating the sample with reference light, light separating means for extracting a part of the return light of the reference light from the sample, and light collecting means for collecting the light extracted by the light separating means, A pinhole plate arranged at the focal position of the light converging means, an optical sensor for detecting the intensity of light passing through the pinhole plate, and an output of the optical sensor, and the detected light intensity becomes maximum. Control the drive of the drive means It was constructed from the control means.

As another solving means, on the premise of the spectroscopic device having the above-mentioned configuration, the light separating means is installed behind the pinhole plate arranged at the focal position of the condensing means, and the light passing through the pinhole plate is arranged. May be separated so that one is incident on the spectroscope and the other is incident on the optical sensor (a sensor that detects the intensity of the received light).

Preferably, the control means compares the light intensity currently acquired with the light intensity previously acquired or before, determines whether or not the focus is moving in a direction, and then, It is configured to have a function of determining a moving direction.

As another means for solving the problem, predetermined light is condensed through a condensing optical system to irradiate the sample, and the return light generated from the sample based on the irradiation is incident on the spectroscope. In a spectroscopic device that performs an analysis process by means of: driving means for changing the distance between the condensing optical system and the sample; means for irradiating the sample with reference light through the condensing optical system; A light separating unit that extracts a part of the return light from the sample, a condensing unit that condenses the light extracted by the light separating unit, and a front and rear position on the optical path with the focus position of the condensing unit interposed therebetween. First and second pinhole plates movably arranged at a distance, and the first and second pinhole plates
Switching means for alternately inserting and arranging the pinhole plates in the optical path, an optical sensor for detecting the intensity of light passing through the first pinhole plate or the second pinhole plate, and an optical sensor for the optical sensor. Control means for receiving the output and controlling the driving of the drive means so that the light intensity of the light passing through the first pinhole plate and the light intensity of the light passing through the second pinhole plate become equal. It consists of and.

Preferably, the control means controls the light intensity of the light passing through the first pinhole plate and the second pinhole plate.
The light intensity of the light passing through the pinhole plate is compared, the direction of the focus is deviated from the magnitude relation, and the function of determining the next movement direction is provided.

Further, the reference light uses measurement light for performing a spectral process. That is, it is better to use the light source for emitting the light for spectroscopic measurement as it is.

[0012]

When the sample to be measured is irradiated with the reference light through the condensing optical system, the return light (Raman scattered light or the like) from the sample is generated, and the return light is partly passed through the light separating means. Are taken out and sent to the light collecting means. Then, the light is collected by the light collecting means and reaches the pinhole plate. At this time, when the position of the sample is coincident with the focal point of the condensing optical system, the returning light is condensed by the condensing means and passes through all the pinholes of the pinhole plate. On the other hand, when the installation position of the sample deviates from the focus position, the position where the light is condensed by the light converging means and converges to one point is displaced from the installation position of the pinhole plate, so that light that cannot pass through the pinhole plate is generated. That is, the intensity of the light passing through the pinhole plate is highest when the focus is achieved. Therefore, the light intensity of the light passing through the pinhole plate is detected by the optical sensor, and the driving device is appropriately driven so as to maximize the light intensity to correct the relative position between the sample and the condensing optical system. Then, when the light intensity reaches the maximum, it is determined to be the in-focus point, and the focusing process ends. Next, when a predetermined light is emitted to actually perform the analysis process, the light passing through the light collecting optical system is condensed (focused) on the sample surface, and highly accurate measurement / analysis is performed.

Further, when the first and second pinhole plates are arranged at equal distances in front and back from the focal position of the light converging means, each pinhole plate is alternately placed at a predetermined position on the optical path. Deploy. Then, when they are in focus, the amounts of light passing through the first and second pinhole plates are equal. On the other hand, when there is no focus, the amount of light passing through one of the pinhole plates is large, and such a large amount of light corresponds to the shift direction. Therefore, the light intensity P1 of the light that has passed through the first pinhole plate and the light intensity P2 of the light that has passed through the second pinhole plate are compared to determine which is greater. When P1 is large, a movement command is output so as to bring the sample closer to the condensing optical system, for example. On the contrary, when P2 is large, the movement command is output to move away. Then, when P1 = P2, the focal points match.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A spectroscopic device according to the present invention will be described in detail below with reference to the accompanying drawings. FIG. 1 shows a first embodiment of the Raman spectroscopic device according to the present invention. As shown in the figure,
First, a condenser lens 2a, a pinhole plate 2b arranged at the focal position of the condenser lens 2a, and a collimator lens placed at a predetermined distance from the pinhole plate 2b on the optical path of the laser light emitted from the light source 1. A beam expander 2 composed of 2c is arranged to convert the laser light emitted from the light source 1 into a parallel light flux having a predetermined diameter.

On the optical path of the laser light that has passed through the beam expander 2, a first half mirror 4 is arranged in a tilted state of 45 degrees. The first half mirror 4 uses, for example, a mirror of about 1: 1 and reflects about 50% of the laser light, converts its path by 90 degrees, and directs it downward. Then, an objective lens 5 which is a condensing optical system is arranged at a predetermined position below the first half mirror 4, and the laser light 2 is condensed by the objective lens 5 so that the laser beam 2 is focused at a predetermined position. Has become. The beam expander 2, the first half mirror 4 and the objective lens 5 compose a condensing optical system. The objective lens 5 is an O.V. L.
It is moved up and down by the operation driver 5a and focused on the sample 6 located below it. Further, the sample 6 is placed on the XY stage 7, and the XY
The sample 6 can be moved in a predetermined direction within a horizontal plane by moving the stage 7 in a predetermined direction by a driving device (not shown).

Further, below the XY stage 7,
A Z stage 8 that is vertically moved by a Z stage driver 8a that is a driving unit is arranged. By vertically moving the Z stage 8, the XY stage 7 and thus the sample 6 can be vertically moved. Then, by appropriately moving the Z stage 8 and the objective lens 5, the focus can be adjusted. In this example, an example in which both the objective lens 5 and the Z stage 8 move up and down has been shown, but at least one of them may move.

On the other hand, at a predetermined position above the first half mirror 4, a second half mirror 9 as a light separating means is provided with a first half mirror 9.
Is arranged in parallel with the half mirror 4. The second half mirror 9 is, for example, a mirror of about 1:99, and is irradiated with laser light to reflect most of the Raman scattered light 10 generated in the sample 6 so that its optical path is 45 degrees. It is designed to be converted and oriented horizontally.
In front of the Raman scattered light 10 traveling in the horizontal direction, a spectroscope 13 is provided via a predetermined beam expander 11.
Is arranged, a detector 14 is connected to the output side of the spectroscope 13, and the detector 14 is sent to a processing device (not shown).
A predetermined spectroscopic measurement is performed there.

Here, in the present invention, a condenser lens 20 as a condenser means is provided above the second half mirror 9, and a pinhole plate 21 is provided at the focal position of the condenser lens 20.
Is provided. An optical sensor 22 is provided above the pinhole plate 21. This optical sensor 22
Is an element that can obtain an output according to the received light intensity, and a photodiode or the like can be used, for example. As a result, a part of the Raman scattered light generated from the sample 6 (second
The light transmitted through the half mirror 9) is received by the optical sensor 22.

The output value is detected by the detecting section 23 and sent to the amplifier 24 to be amplified by a predetermined factor and then converted into a digital value of the A / D converter 25, which is the CPU 2 as a control means.
Give to 6.

The CPU 26 judges on the basis of the given data whether or not it is in focus, and if not, O.S. L. A movement command is output to the operation driver 5a and / or the Z stage driver 8a. That is, assuming that the laser light emitted from the light source 1 is focused on the surface of the sample 6, the Raman scattered light passes through the objective lens 5 and becomes a parallel light beam. Since the formed light forms an image on the pinhole plate 21, all of the light transmitted through the second half mirror 9 is received by the optical sensor 22. However, when the surface of the sample 6 does not exist at the focal position of the objective lens 5, the amount of light passing through the pinhole plate 21 decreases. Therefore, the CPU 26 appropriately moves the Z stage 8 or the objective lens 5 up and down, and the optical sensor 2
When the amount of received light of 2 is maximized, it is determined that the focal points match, and the drivers 5a and 8a are stopped.

Further, in the present example, attention is paid to the fact that the light intensity increases as it gets closer to the focal point, and the processing as shown in FIG. 2 is performed. First, the light intensity P0 acquired for the first time,
The light intensities P1 acquired after moving (raising / lowering) in a predetermined direction are compared (ST1 to ST4). Then, when the light intensity P1 acquired this time is higher, it is the direction closer to the focal length, so that it is moved in the same direction (ST5), and P1 is set.
If is smaller than the focal length, it is moved away from the focal length (ST6).

After that, each time the reference distance is moved in the direction determined in step 5 or step 6, the light intensity Pn is acquired, and the value is compared with the previously acquired light intensity P (n-1) (the acquired light intensity Pn). The intensity is stored only once (by overwriting in the buffer and prepared for comparison with the next acquired data), and the above process is repeated until the current light intensity Pn becomes smaller (or equal) (ST7 to ST10). ).

If Pn≤P (n-1), the previous light intensity P (n-1) becomes maximum, so the previous positional relationship (distance between the objective lens 5 and the sample 6 (relative In order to return to (positional relation)), a command is issued to a predetermined driver to move in a reverse direction by a reference distance (ST11).

As described above, in this example, the laser light emitted for measuring the sample also serves as the reference light for focusing.

The control (autofocus) process in the CPU 26 is not limited to the above-described one, and for example, the objective lens 5 or the Z stage 8 is moved in a certain direction from a certain initial position, and light is received at a predetermined sampling time. The amount is acquired and stored together with the position data at that time. Then, the maximum value of the amount of received light may be detected and a movement command may be output to the predetermined drivers 5a and 8a so as to obtain the position data at that time. In short, the position where the amount of received light is maximum is detected. It suffices that each member be set at that position.

While performing Raman measurement and the like, sample 6
In order to be able to observe the surface condition of
A half mirror 27 is arranged between the condenser lens 20 and the pinhole plate 27 so that a part of the light can enter the CCD 28. And, although not shown, a CCD
The output of 28 is sent to a predetermined image processing device or the like.

Next, the operation of the above embodiment will be described. First, focusing is performed prior to Raman analysis by the spectroscope 13. That is, when the laser light as the reference light is emitted from the light source 1, most of the emitted laser light of the sample 6 is narrowed down via the first half mirror 4 and the objective lens 5 as described above. It is irradiated at a predetermined position.

Raman scattered light 10 is generated by the irradiation, and the Raman scattered light 10 is emitted from the objective lens 5.
And becomes a parallel light flux, and reaches the second half mirror 9. Then, a part of the Raman scattered light is transmitted and rises as it is. The Raman scattered light 10 traveling upward is condensed by the condenser lens 20 and received by the optical sensor 22 via the pinhole plate 21.

At this time, the optical sensor 22 has the condenser lens 20.
Since it is arranged immediately behind the pinhole plate 21 arranged at the focal position of, the received light is the state of Raman scattered light when it is generated from the sample 6, that is, the laser light to the sample 6. This is equivalent to the irradiation state, and the magnitude of the intensity of the light incident on the optical sensor 22 directly corresponds to whether or not the sample 6 is located on the focal position of the objective lens 5, and the greater the light intensity, the more the focus. It can be said that

Therefore, the received light intensity data is sent to the CPU 2
6, the light intensity is increased / decreased, the magnitude thereof is used to determine whether the focus is in the in-focus direction or the defocusing direction, and the predetermined driver 5 is operated based on the determination result.
The objective lens 5 and / or the Z stage 8 are moved up and down by a predetermined amount via a and 8a.

Then, the movement is stopped at the position where the light intensity is maximized. Then, this stop is in a positional relationship in which the focus is the most. This completes the autofocus process.

Next, the Raman scattered light 10 incident on the spectroscope 13 in this state is subjected to Raman analysis processing using the computer 14, and ordinary predetermined processing such as sample identification and surface state detection is performed. . That is, the laser light after the generation of the processing completion signal becomes the light in the normal analysis processing.

Further, in this example, since the focus position can be accurately adjusted to each position of the sample 6 as described above, the sample 6 may be composed of a plurality of layers having a predetermined film thickness, for example. In this case, since the position (depth) from the surface of the sample 6 to the surface of the predetermined internal layer (interface between the upper and lower layers) is known, the objective lens 5 is predetermined after the focusing. The desired state of the interface can be measured by lowering the distance or raising the Z stage 8.

As described above, in this example, the light source 1 for the reference light for focusing and the light source 1 for Raman analysis are used in common, and the laser under the same conditions is used at the actual analysis location. Focusing is performed by irradiating light, and since there is no mechanical switching processing etc. even after that focusing, extremely accurate focusing can be performed, the accuracy of the subsequent analysis processing is improved, and real time It can be processed quickly.

FIG. 3 shows a second embodiment of the present invention. In this embodiment, the installation position of the optical sensor 22 is different from the first embodiment described above. That is, the third half mirror, which is a light splitting means, is located behind the beam expander 11 on the optical path reflected by the second half mirror 9 and incident on the spectroscope 13, that is, between the beam expander 11 and the spectroscope 13. The 30 is arranged at an angle of 45 degrees with respect to the optical path, a part of the light is reflected, the path is changed by 90 degrees, and the light is directed upward. The condenser lens 20 is arranged at a predetermined position above the third half mirror 30, and the optical sensor 22 is arranged at the focal position of the condenser lens 20.

However, as in the first embodiment, the optical sensor 22
No pinhole plate 21 is provided in front of the. That is,
A pinhole plate 11b is provided at the focal position of the condenser lens 11a that constitutes the beam expander 11, and this pinhole plate 11b is also the focal position of the collimator lens 11c in the subsequent stage.

Then, the sample 6 is placed at the focal position of the objective lens 5.
When the surface of is positioned, the Raman scattered light emitted from the surface is converted into a parallel light flux by moving backward through the objective lens 5 as described above, and passes through the first half mirror 4,
The light reaches the condenser lens 11a reflected by the second half mirror 9 and is condensed there. However, since the pinhole plate 11b exists at the focal position, all the light passing through the condenser lens 11a is pinned. It passes through the hole plate 11b and reaches the collimator lens 11c.

On the other hand, from the focus position of the objective lens 5 to the sample 6
If the deviation occurs, all the light condensed by the condenser lens 11a cannot pass through the pinhole plate 11b. That is, the intensity of light passing through the pinhole plate 11b is maximized when the focus position is correct.

Therefore, since the pinhole plate 11b exhibits the same function as the pinhole plate 21 in the above-described first embodiment, a part of the light which has passed through the pinhole plate 11b is partially reflected by the third half mirror 30. Then, the light intensity is detected by the optical sensor 22, and the same effect as that of the first embodiment is exhibited. That is, in this embodiment, the pinhole plate 11b has both the function of the beam expander 11 and the function of focusing.
This not only reduces the number of parts, but also requires each pinhole plate to be accurately positioned on the focal length of the corresponding condenser lens, which makes the adjustment work extremely complicated, but the work is Assembling work becomes easy because it is not necessary for each batch. Moreover, since the focusing can be performed by using a part of the light that actually enters the spectroscope 13, more accurate focusing can be performed.

In this embodiment, since no optical sensor is provided above the second half mirror 9, when the CCD 28 is installed, a condenser lens is provided above the second half mirror 9 as shown in the figure. 27 can be placed at a distance.
When the detection by the CCD 28 and the detection by the spectroscope 13 are not performed at the same time, a switching mirror may be provided instead of the half mirror 9. In addition, CCD 28 (condensing lens 27)
Of course, when not provided, a mirror may be installed instead of the half mirror. Since the other construction and the operation and effect of each part are the same as those in the above-described first embodiment, the same reference numerals are given and the description thereof is omitted.

FIG. 4 shows a third embodiment of the present invention.
In the present embodiment, unlike both the above-described embodiments, two pinhole plates for focusing are used, and the pinhole plates are alternately inserted into the optical path. If not, if not, which direction to move should be determined.

That is, on the optical path of the Raman scattered light transmitted through the second half mirror 9, the first pinhole is equidistantly spaced before and after the focal point O of the condenser lens 20 arranged above the Raman scattered light. A plate 32 and a second pinhole plate 33 are arranged. And, both of these pinhole plates 32, 33
Is movable by a pinhole switching drive device 34 and is alternately inserted into the optical path.

The movement may be linear movement or rotational movement. In this example, the forward and reverse rotations are alternately performed around a certain reference position, and moreover, the pinholes of the first pinhole plate 32 (second pinhole plate 33) start to reach the optical path. Sometimes the second pinhole plate 33
The (first pinhole plate 32) is set so as to be completely away from the optical path.

Further, the optical sensor 22 is arranged behind both the pinhole plates 32 and 33. As a result, the optical sensor 22
Assuming that the intensity of scattered light generated is constant, the amount of light passing through the pinhole increases as the pinhole in the pinhole plate gradually enters the optical path. Therefore, the light intensity also increases. Then, it becomes the maximum when it completely coincides with the optical path, and conversely, when it goes away, the amount of light passing through the pinhole decreases as the pinhole of the pinhole plate gradually deviates from the optical path. Also decreases.

Therefore, for example, as shown in FIG.
The output of the optical sensor has a waveform that changes in an analog manner. Then, the pinhole switching drive device 34 includes the CPU 2
Switching drive / control is performed at a constant timing based on a control signal from 6 '.

Further, as described above, the sensor output has a wave shape, and the output (corresponding to the current relative position between the sample 6 and the objective lens 5) when the pinhole plates 32 and 33 are completely positioned on the optical path. Since the original output obtained by the relationship becomes the peak value of the above waveform, the output of the amplifier 24 is given to the peak hold circuit 36, the peak value (peak value) is detected, and the value is sent to the A / D converter 25. It is designed to be sent to the CPU 26 'via the.

Further, it is determined whether the light intensity detected by the optical sensor 22 (peak hold circuit 36) is the output when one of the first and second pinhole plates 32 and 33 is arranged on the optical path. In order to detect, a sensor 35 such as a proximity switch is arranged, and the sensor 35 detects a pinhole plate inserted and arranged on the optical path, and the information is detected by the CPU 2
I am going to send it to 6 '.

Further, the output of the sensor 35 is the delay circuit 37.
The reset signal is applied to the peak hold circuit 36 after a predetermined time has elapsed after receiving the detection signal. The peak hold circuit 36 repeats the hold value based on the reset signal to detect a new peak value. As a result, the peak value (light intensity) based on the first pinhole plate 32 and the peak value (light intensity) based on the second pinhole plate 33 are alternately detected, and the peak value (light intensity) is detected via the A / D converter 25. Can be given to the CPU 26.

Next, the processing of the focusing function in the CPU 26 'will be described. First, as shown in FIG. 5 (A), when the focus is on the second pinhole plate 33 side with respect to the focus position O, as is apparent from the figure, the first pinhole plate 33 32 is more light blocking.
Therefore, the light intensity P2 when the second pinhole plate 33 is placed on the optical path is higher than the light intensity P1 when the first pinhole plate 32 is placed on the optical path.

On the contrary, as shown in FIG. 6B, when the focal point is closer to the first pinhole plate 32 side than the focal position O, as shown in FIG. The second pinhole plate 33 has a larger amount of blocking light. Therefore, the first
The light intensity P2 when the second pinhole plate 33 is placed on the optical path is smaller than the light intensity P1 when the pinhole plate 32 is placed on the optical path.

Further, as shown in FIG. 6C, when the focus is achieved, the first and second pinhole plates 32,
The amount of light passing through 33 is equal. Therefore, the light intensity P1 when the first pinhole plate 32 is placed on the optical path is equal to the light intensity P2 when the second pinhole plate 33 is placed on the optical path.

Therefore, the CPU 26 'detects the sync signal from the sensor 35 (detection signal of the pinhole plate) from the optical sensor 2.
It is detected whether the data based on the light intensity detected in 2 is based on the light passing through the first and second pinhole plates 32 and 33, and the light of the light passing through the first pinhole plate 32 is detected. The intensity P1 and the light intensity P2 of the light that has passed through the second pinhole plate 33 are compared to determine which is greater.

When P1 is large, for example, Z
A movement command is output to the stage operating driver 8a so that the Z stage 8 moves up by a predetermined distance (the objective lens 5 moves down with respect to the OL operating driver 5a). Conversely, when P2 is large, for example, a movement command is issued to the Z stage actuation driver 8a so that the Z stage 8 descends by a predetermined distance (the objective lens 5 rises with respect to the OL actuation driver 5a). Output. When the two peak values are equal, it is determined that the focal points match, and a movement stop command is issued to each of the drivers 5a and 8a.

That is, in this example, by measuring the magnitude of the light intensity, it is possible to determine whether or not there is a focus, and when it is out of focus, which one is deviated. That is, it is not necessary to relatively move the objective lens 5 and the sample 6 once when determining the moving direction (the direction in which the focus is achieved) as in the first and second embodiments described above, and both Since it suffices to stop the movement when the light intensities become equal, there is no need to return in the opposite direction as in the above-mentioned embodiments, and high-speed focusing can be performed. Since the other configurations and operational effects are the same as those of the above-described embodiments, the same reference numerals are given and detailed description thereof will be omitted.

Although laser light is used as the light for irradiating the sample 6 in each of the above-described embodiments, the present invention is not limited to this, and white light or other appropriate light can be used. In this case, the pinhole 2b on the irradiation light side is required. Further, in each of the above-described embodiments, an example in which all are applied to a Raman spectroscope has been described, but the present invention is not limited to this, and may be applied to various types of spectroscopic devices such as an infrared spectroscope. it can.

[0056]

As described above, in the spectroscopic device according to the present invention, the sample to be measured is irradiated with the reference light, the return light is received by the optical sensor, and the magnitude of the light intensity is determined. , It is possible to judge whether the focus is in agreement. That is, in the inventions of claims 1 to 3, the time when the output of the photosensor becomes maximum is when the focus is achieved. In the inventions of claims 4 and 5, the light passing through the first pinhole plate is detected. This is because when the light intensity (light sensor output) and the light intensity of light passing through the second pinhole plate (light sensor output) are equal to each other, it is when the focus is achieved.

When they do not coincide with each other, the sample and the optical system for condensing the light can be relatively moved so as to coincide with each other, and the distance between the two can be automatically adjusted. As a result, the sample can be placed almost on the focus of the condensed light during the analysis process, and the measurement accuracy can be improved. Then focus (auto focus)
Therefore, by setting the position of the light irradiated on the sample and the position of the actual measurement at the same position, accurate position (focus) can be adjusted and the measurement accuracy is further improved.

As described above, the determination processing such as the presence / absence of the coincidence of the focal points can be performed by a simple configuration and measurement principle of knowing the magnitude relation of the light intensity received by the optical sensor, and the determination processing is performed by the comparison processing. Therefore, the processing can be performed with a simple configuration, and the device can be simplified and further speeded up.

Further, since the focusing (detection) on the surface of the sample can be performed accurately as described above, it is possible to accurately measure the position at the depth (inside) from the surface to a certain depth.

When not in focus, the method according to claim 1
In the invention of 3, the light intensity data obtained this time is compared with the light intensity data obtained last time or before, and if it is higher this time, it is closer to the focus, so it is sufficient to continue moving in the same direction, and vice versa. You can move it in the opposite direction. Further, in the case of the inventions of claims 4 and 5, it is possible to know the direction deviated from the focus by detecting the pinhole plate having a high light intensity. As described above, the displacement direction can be easily detected simply by observing the magnitude relationship of the outputs of the optical sensors (the larger the difference, the larger the displacement amount). Therefore, it is possible to perform focusing in a short time without making a mistake in the moving direction for focusing.

When a laser for spectroscopic measurement is used as a reference light for focusing (a part of the light used for measurement is used for light for position (focus)) (claim 6). Therefore, it is possible to directly shift to the spectroscopic measurement, and the measurement accuracy is further improved.

[Brief description of drawings]

FIG. 1 is a diagram showing a first embodiment of a spectroscopic device according to the present invention.

FIG. 2 is a flowchart illustrating a function of a CPU.

FIG. 3 is a diagram showing a second embodiment of the spectroscopic device according to the present invention.

FIG. 4 is a diagram showing a third embodiment of the spectroscopic device according to the present invention.

FIG. 5 is a diagram illustrating the operation thereof.

[Explanation of symbols]

 1 light source 5 objective lens (condensing optical system) 5a O. L. Operation driver (driving means) 6 Sample 8 Z stage 8a Z stage driver (driving means) 9 Second half mirror (light separating means) 11b Pinhole plate 13 Spectroscope 20 Focusing lens (focusing means) 21 Pinhole Plate 22 Optical sensor 26, 26 'CPU (control means) 30 Third half mirror (light separating means) 32 First pinhole plate 33 Second pinhole plate

Claims (6)

[Claims] 1. A spectroscope that performs analysis processing by collecting predetermined light through a condensing optical system to irradiate a sample, and based on the irradiation, return light generated from the sample is incident on a spectroscope. In the apparatus, driving means for changing the distance between the condensing optical system and the sample, means for irradiating the sample with reference light via the condensing optical system, and return light of the reference light from the sample. A light separating means for extracting a part of the light, a light collecting means for collecting the light extracted by the light separating means, a pinhole plate arranged at the focal position of the light collecting means, and a light passing through the pinhole plate. A spectroscopic device comprising an optical sensor for detecting the intensity of the light, and a control means for receiving the output of the optical sensor and controlling the driving of the drive means so that the detected light intensity is maximized. 2. A spectroscope that performs analysis processing by collecting predetermined light through a condensing optical system to irradiate a sample, and based on the irradiation, return light generated from the sample is incident on a spectroscope. In the apparatus, driving means for changing the distance between the condensing optical system and the sample, means for irradiating the sample with reference light via the condensing optical system, and return light of the reference light from the sample. And a pinhole plate arranged at the focal position of the light condensing unit, and light that has passed through the pinhole plate is separated, one of which is incident on the spectroscope and the other of which is A spectroscopic device comprising: a means for making the light incident on an optical sensor for detecting the intensity; and a control means for receiving the output of the optical sensor and controlling the driving of the driving means so that the detected light intensity becomes maximum. 3. The control means compares the currently acquired light intensity with the previously or previously acquired light intensity,
The spectroscopic apparatus according to claim 1 or 2, further comprising a function of determining whether or not a moving direction is in focus and determining a next moving direction. 4. A spectroscope that performs analysis processing by collecting a predetermined light through a condensing optical system and irradiating the sample with the return light that is generated from the sample and is incident on a spectroscope based on the irradiation. In the apparatus, driving means for changing the distance between the condensing optical system and the sample, means for irradiating the sample with reference light via the condensing optical system, and return light of the reference light from the sample. And a light condensing means for condensing the light extracted by the light separating means, and a front and rear optical path that can be moved at equal distances across the focal point of the light condensing means. First and second pinhole plates, switching means for alternately inserting and arranging the first and second pinhole plates on the optical path, the first pinhole plate or the second pinhole plate. An optical sensor that detects the intensity of light that has passed through the pinhole plate of The driving means so that the light intensity of the light passing through the first pinhole plate and the light intensity of the light passing through the second pinhole plate are equalized by receiving the output of the light sensor. And a control means for controlling driving of the spectroscopic device. 5. The control means compares the light intensity of light that has passed through the first pinhole plate with the light intensity of light that has passed through the second pinhole plate. The spectroscopic device according to claim 4, further comprising a function of determining whether the focus is deviated in the direction of, and determining the next moving direction. 6. The spectroscopic device according to claim 1, wherein the reference light is the predetermined light for performing a spectral process.