JP2012194007A - Atr mapping method and atr mapping apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ATR mapping method and an ATR mapping apparatus in which ATR mapping analysis can be performed at low costs without iteratively crimping and separating a sample and an ATR prism.SOLUTION: An infrared detection unit 9 in an embodiment comprises an infrared detector 15 with which a photo detection section 151 is disposed on an image forming plane of an image forming optical system, and a detector moving mechanism 16 which moves the photo detection section 151 on the image forming plane by moving the infrared detector 15 in parallel with the image forming plane. On the image forming plane where the photo detection section 151 is present, an image of a contact face between a sample and an ATR prism is magnified and formed in accordance with a magnification ratio of the image forming optical system. The photo detection section 151 is moved to cover the overall magnified image and by scanning the image of the contact face on the image forming plane, mapping measurement is performed.

Description

  The present invention relates to a mapping analysis method by a total reflection measurement method and an apparatus using the method.

  One of the surface analysis methods performed with a Fourier transform infrared spectrophotometer (FTIR) or an infrared microscope is the total reflection measurement method (Attenuated Total Reflectance = ATR method). In the ATR method, as shown in FIG. 5A, a prism (ATR prism) 20 made of a material having a refractive index higher than that of the sample S is pressure-bonded to the surface of the sample S, and the boundary between the ATR prism 20 and the sample S Infrared light is incident on the surface 21 from the ATR prism 20 side at an incident angle greater than the total reflection critical angle. Under this condition, the infrared light is totally reflected at the boundary surface 21, but a part of the infrared light penetrates to the side of the sample S beyond the boundary surface 21 (FIG. 5B), and is more specific to the surface portion of the sample S. Get absorbed. Thus, the sample surface can be analyzed by measuring the absorption spectrum of infrared light reflected on the sample surface (see, for example, Patent Document 1).

  One application of the ATR method is ATR mapping analysis. In the ATR mapping analysis, measurement is performed by the ATR method at a plurality of points (hereinafter referred to as “analysis points”) in a predetermined region on the sample surface, and the measurement results in the region are mapped. When performing ATR mapping analysis, in the conventional method, the sample and the prism are repeatedly pressed and separated for each analysis point while changing the relative position of the sample and the prism.

JP-A-4-348254 US Pat. No. 6,141,100

  However, it takes time to repeat such crimping and separation. Further, by repeating the pressure bonding and separation, there is a high possibility that the prism is damaged or impurities are interposed during measurement. Furthermore, when the distance between the analysis points is reduced, high accuracy is required for positioning the prism.

  Further, the size of the contact surface (boundary surface) between the ATR prism and the sample is 100 μm or less in diameter although it depends on the hardness of the sample. Therefore, if mapping is performed at intervals less than the size of the contact surface, the same location will be repeatedly pressed, and unmeasured parts may be damaged or deformed, which may adversely affect measurement results. .

  On the other hand, Patent Document 2 shows a method of measuring an image of a contact surface obtained by forming an image of light totally reflected on the contact surface using a two-dimensional array detector. In the method of Patent Document 2, the measurement data in each light receiving element of the two-dimensional array detector is data from the total reflection position of the corresponding contact surface.

  However, the method of Patent Document 2 has the following problems in performing infrared analysis. A silicon array detector available at low cost has high sensitivity in the visible range, but cannot detect infrared light. On the other hand, array detectors for infrared light other than silicon, although available, are very expensive. Furthermore, since the number of light receiving elements is fixed, an excessive amount of data must be obtained for samples with little change, or a sufficient number of data cannot be obtained for samples with significant changes. There is.

  The problem to be solved by the present invention is to provide an ATR mapping method and an ATR mapping apparatus capable of performing ATR mapping analysis at low cost without repeating the pressing and separation of a sample and a prism.

An ATR mapping method according to the present invention made to solve the above problems is as follows:
Measuring light is introduced into the contact surface between the sample and the ATR prism,
By guiding the measurement light totally reflected by the contact surface to a predetermined imaging optical system, an image of the contact surface is formed on the imaging surface of the imaging optical system,
By measuring the light intensity at each position of the image of the contact surface imaged on the imaging surface by moving the light receiving portion of the detector along the imaging surface,
Based on the measurement result of the light intensity at each position of the image of the contact surface, mapping data is created.
It is characterized by that.

Further, an ATR mapping apparatus according to the present invention, which has been made to solve the above problems,
An introduction optical system for introducing measurement light into the contact surface between the sample and the ATR prism;
An imaging optical system that forms an image of the contact surface on a predetermined image formation surface with the measurement light totally reflected by the contact surface;
A detector for measuring light intensity at each position of the image of the contact surface on the imaging plane;
Moving means for moving the light receiving part of the detector on the sample image;
Mapping data creating means for creating mapping data based on the measurement result of the light intensity at each position of the image of the contact surface;
It is characterized by having.

  The present invention guides measurement light totally reflected by a contact surface between a sample and an ATR prism to a predetermined imaging optical system, and detects an image of the contact surface formed on the imaging surface of the imaging optical system as a detector. The mapping analysis is performed by scanning the light receiving unit. In the configuration of the present invention, since it is not necessary to use a two-dimensional array detector, the cost required for the detector is reduced. In addition, mapping analysis of the contact surface can be performed without repeating the pressing and separation of the sample and the ATR prism. Further, since the image of the enlarged contact surface is scanned, the scanning interval on the image can be set wider than on the sample, and it is not necessary to use an expensive moving mechanism with high accuracy.

  In the ATR mapping method and the ATR mapping apparatus according to the present invention, the imaging optical system can change the magnification of the image on the contact surface, and the position of the imaging surface on the optical axis accompanying the change in magnification can be changed. It is desirable to have a configuration in which the detector can be moved along the optical axis in response to the change. As a result, it is possible to adjust the light intensity of the measurement light introduced into the light receiving part of the detector and to create more detailed mapping data while keeping the scanning interval on the image constant. The degree of freedom is higher.

  In the ATR mapping method and the ATR mapping apparatus according to the present invention, the contact surface mapping analysis can be performed while the prism is pressure-bonded to the sample, so that the analysis time can be shortened. In addition, since the number of repeated pressing and separation is reduced, the possibility that the prism is broken or impurities are interposed during the measurement is reduced. Furthermore, since the image of the enlarged contact surface is scanned, the cost for the detector and the moving mechanism can be reduced.

The schematic block diagram of the infrared microscope which is one Example of the ATR mapping apparatus which concerns on this invention. The perspective view of the infrared detection part of the infrared microscope of a present Example. Explanatory drawing of the ATR mapping analysis by the infrared microscope of a present Example. The schematic block diagram of the modification of the infrared microscope of a present Example. Explanatory drawing of the principle of ATR method.

  An infrared microscope as an embodiment of the ATR mapping apparatus according to the present invention will be described with reference to the drawings. FIG. 1 is a schematic configuration diagram of the infrared microscope of the present embodiment, FIG. 2 is a perspective view of an infrared detection unit of the infrared microscope of the present embodiment, and FIG. 3 is an explanation of ATR mapping analysis by the infrared microscope of the present embodiment. FIG.

  The infrared microscope of the present embodiment shown in FIG. 1 emits infrared light that emits infrared light and infrared light incident from the infrared light source 1 as interference light (hereinafter referred to as “measurement light”). Interferometer 2, visible light source 3 that emits visible light (hereinafter referred to as “observation light”) for observing the sample surface, and ATR prism 5 that is pressure-bonded to sample S placed on movable stage 4. And a Cassegrain objective mirror 6 for condensing the measurement light and the observation light on the contact surface between the sample and the ATR prism 5 and condensing the measurement light and the observation light reflected by the contact surface on the sample S; An aperture 7 that shields the measurement light and the observation light reflected from other than the specific part, an observation optical system 8 for observing an image of the contact surface formed by the observation light that has passed through the aperture 7, and the aperture 7 Of image of contact surface formed by measured measuring light Infrared detector 9 that performs measurement, control of movable stage 4 and infrared detector 9, and personal computer (PC) 10 that creates mapping data based on the measurement result of infrared detector 9, and each position on the optical path And mirrors 11 and 12 that reflect both the measurement light and the observation light, and half mirrors 13 and 14 that reflect the measurement light and transmit the observation light.

  In the infrared microscope of the present embodiment, the infrared light source 1, the interferometer 2, the mirror 11, the half mirror 13, the mirror 12, the ATR prism 5, and the Cassegrain type objective mirror 6 are used as the introduction optical system, the ATR prism 5 and the Cassegrain type objective. The mirror 6, the aperture 7, and the half mirror 14 correspond to the imaging optical system.

  As shown in FIG. 2, the infrared detection unit 9 of the present embodiment is in parallel with the infrared detector 15 in which the light receiving unit 151 is disposed on the imaging surface of the imaging optical system (that is, light And a detector moving mechanism 16 that moves the light receiving unit 151 on the imaging plane by moving the infrared detector 15 in a direction perpendicular to the axis.

  The PC 10 installs a dedicated program to control the position of the sample S by the movable stage 4 and the position control of the infrared detector 15 (more specifically, the light receiving unit 151) by the detector moving mechanism 16. It functions as an arithmetic unit that creates mapping data based on the result of measuring the light intensity at each position of the image of the contact surface. In this embodiment, the infrared microscope and the PC 10 are separated from each other, but they may be integrated.

  As shown in FIG. 1, in the infrared microscope of this embodiment, infrared interference light (measurement light) obtained from the infrared light source 1 and the interferometer 2 and observation light obtained from the visible light source 3 are transmitted in the half mirror 13. After being mixed, the light enters the Cassegrain type objective mirror 6 through the mirror 12. The sample S placed on the movable stage 4 is stationary with the ATR prism 5 being crimped, and the measurement light and observation light incident on the Cassegrain type objective mirror 6 are condensed, and the ATR prism 5 and the sample S are collected. Introduced on the contact surface.

  The measurement light and the observation light are reflected by the contact surface and guided to the aperture 7 through the Cassegrain objective mirror 6. In the aperture 7, only the light reflected by a specific part passes, and the half-mirror 14 distributes the observation light to the observation optical system 8 and the measurement light to the infrared detection unit 9.

  On the imaging surface where the light receiving unit 151 is located, the image on the contact surface is enlarged and imaged according to the magnification of the imaging optical system. The PC 10 controls the detector moving mechanism 16 so that the light receiving unit 151 covers the entire enlarged image, and scans the image of the contact surface on the imaging surface (FIG. 3).

  The measurement data of the light intensity at each position of the light receiving unit 151 is sent to the PC 10 through predetermined signal processing, and the position information of the light receiving unit 151 and the measurement data are stored in association with each other. Finally, the PC 10 creates mapping data by associating the position information of the light receiving unit 151 with the position information on the sample S based on the magnification of the imaging optical system.

  In the infrared microscope of this embodiment, for example, when the contact surface is magnified 10 times by the imaging optical system, the sample S can be obtained by moving the light receiving portions 151 at intervals of 100 μm on the imaging surface. The same result as when the relative position with the ATR prism is changed at intervals of 10 μm on the side is obtained. Since the image thus enlarged is scanned, even if the position accuracy of the detector moving mechanism 16 is low, the mapping analysis itself can be performed with high accuracy.

  As described above, after creating mapping data on a certain contact surface, the movable stage 4 is moved, the relative position between the sample S and the ATR prism 5 is changed, and mapping measurement is performed on the new contact surface by the above method. To start. The PC 10 creates mapping data for the entire surface of the sample S based on the position information of the new contact surface and the mapping data created for the contact surface.

  Next, a modification of the infrared microscope of the above embodiment is shown in FIG. In the infrared microscope of this modification, an imaging lens 17 that can move along the optical axis according to the control of the PC 10 is disposed on the optical path between the Cassegrain objective mirror 6 and the infrared detector 9. In addition, as the detector moving mechanism 16 used in the infrared detector 9, a mechanism capable of moving the infrared detector 15 in a direction parallel to the optical axis is used.

  In the infrared microscope of this modification, the Cassegrain objective mirror 6, the aperture 7, the half mirror 14, and the imaging lens 17 serve as an imaging optical system. In this imaging optical system, the image magnification can be changed. For example, if the image magnification is increased, the corresponding analysis on the sample S can be performed even if the position accuracy of the detector moving mechanism 16 on the imaging surface is the same. It becomes possible to create more detailed mapping data with a smaller distance between points.

  Since the position of the imaging plane changes when the image magnification is changed, the PC 10 controls the position of the imaging lens 17 and at the same time the infrared detector 15 (or the light receiving unit 151) in the optical axis direction by the detector moving mechanism 16. Position control is performed so that the light receiving unit 151 is arranged on a new imaging plane. The position of the infrared detector 15 in the optical axis direction may be calculated by the PC 10 every time the position of the imaging lens 17 is changed. However, the position information of the imaging lens 17 and the position of the infrared detector 15 are stored in the storage unit of the PC 10. A table associated with the position information may be stored, and the infrared detector 15 may be moved with reference to the table each time the imaging lens 17 is moved.

  As described above, the ATR mapping apparatus and the ATR mapping method according to the present invention have been described using the embodiments. However, it is obvious that the above is only an example, and appropriate changes or modifications within the scope of the present invention, or You may add.

DESCRIPTION OF SYMBOLS 1 ... Infrared light source 2 ... Interferometer 3 ... Visible light source 4 ... Movable stage 5 ... ATR prism 6 ... Cassegrain type objective mirror 7 ... Aperture 8 ... Observation optical system 9 ... Infrared detector 10 ... Personal computer (PC)
DESCRIPTION OF SYMBOLS 11, 12 ... Mirror 13, 14 ... Half mirror 15 ... Infrared detector 151 ... Light receiving part 16 ... Detector moving mechanism 17 ... Imaging lens 20 ... ATR prism 21 ... Boundary surface S ... Sample

Claims (6)

Measuring light is introduced into the contact surface between the sample and the ATR prism,
By guiding the measurement light totally reflected by the contact surface to a predetermined imaging optical system, an image of the contact surface is formed on the imaging surface of the imaging optical system,
By measuring the light intensity at each position of the image of the contact surface imaged on the imaging surface by moving the light receiving portion of the detector along the imaging surface,
Based on the measurement result of the light intensity at each position of the image of the contact surface, mapping data is created.
An ATR mapping method characterized by the above.   When creating the mapping data, each position on the image is made to correspond to each position on the contact surface between the sample and the ATR prism based on the magnification of the imaging optical system. The ATR mapping method according to claim 1.   The imaging optical system can change the image magnification, and the light receiving unit is moved along the optical axis in response to a change in the position of the imaging surface on the optical axis accompanying the change in the magnification. The ATR mapping method according to claim 1 or 2. An introduction optical system for introducing measurement light into the contact surface between the sample and the ATR prism;
An imaging optical system that forms an image of the contact surface on a predetermined image formation surface with the measurement light totally reflected by the contact surface;
A detector for measuring light intensity at each position of the image of the contact surface on the imaging plane;
Moving means for moving the light receiving part of the detector on the sample image;
Mapping data creating means for creating mapping data based on the measurement result of the light intensity at each position of the image of the contact surface;
An ATR mapping apparatus comprising:   When creating the mapping data, each position on the image is made to correspond to each position on the contact surface between the sample and the ATR prism based on the magnification of the imaging optical system. The ATR mapping apparatus according to claim 4. The image magnification change means for changing the image magnification of the imaging optical system is further provided, and the moving means is capable of moving the light receiving section also in the optical axis direction. 5. The ATR mapping apparatus according to 5.

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