JP2010164854A - Microscope apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a microscope apparatus which has improved observation performance by selectively switching observation light sources. <P>SOLUTION: The microscope apparatus 1 includes: a plurality of light sources (2, 3); and an optical coupling means (4a) which couples the light emitted from the plurality of light sources (2, 3). Preferably, the microscope apparatus 1 further includes a light source switching means (4) which moves the optical coupling means (4a) to a position in the optical paths L of the light emitted from the light sources (2, 3) and to a position retracted from the above position. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a microscope apparatus including a plurality of light sources.

  Conventionally, many halogen light sources have been used as light sources for observation of microscopes. In recent years, however, LED light sources have become very popular due to higher brightness and lower prices, and they are no exception as light sources for microscopes. An LED is a light source that has a long life and low power consumption, and has a small amount of heat generation compared to a halogen.

  On the other hand, there is a need to use a mercury xenon light source having higher brightness than halogen or LED, a lamp house for IR observation using infrared light, and the like.

  However, each light source has its merits and demerits, and LED light sources aiming at replacement of general halogen light sources have characteristics such as wavelength characteristics and disadvantages such as insufficient luminance and unsuitable for dark field observation. Yes. In addition, the high brightness mercury xenon light source cannot be dimmed by voltage, so it cannot be said that it is very convenient.

  Therefore, a method of arranging two types of light sources and selectively switching the observation light source is used (for example, see Patent Documents 1 to 3).

JP 2005-326544 A JP 2006-267432 A JP-A-2005-300614

  By the way, for example, the observation performance of a specimen such as a substrate for a flat panel display (FPD) such as a liquid crystal display (LCD) or a semiconductor wafer is required to be highly accurate year by year.

For this reason, it has become impossible to perform sufficient observation of a specimen simply by selectively switching the observation light source.
The objective of this invention is providing the microscope apparatus which can improve observation performance.

The microscope apparatus of the present invention includes a plurality of light sources and an optical coupling unit that couples light emitted from the plurality of light sources.
Preferably, the microscope apparatus further includes light source switching means for moving the optical coupling means to a position in an optical path of light emitted from the light source and a position retracted therefrom.

  More preferably, the microscope apparatus further includes light deflecting means for deflecting light emitted from at least one of the plurality of light sources, and the light source switching means includes the light deflecting means, the optical coupling means, and the like. Is configured to be selectively moved in the optical path of the light emitted from the light source.

  Preferably, the microscope apparatus further includes a plurality of filters, and a filter switching unit that moves at least one of the plurality of filters on an optical path of light emitted from the light source according to an observation mode. To do.

Preferably, the plurality of light sources includes two or more types of light sources.
Preferably, the optical coupling means is a half mirror.

In the present invention, by combining light emitted from a plurality of light sources, observation that is difficult with a single light source can be performed.
Therefore, according to the present invention, observation performance can be improved.

It is a schematic plan view which shows the internal structure of the microscope apparatus which concerns on one embodiment of this invention. It is a schematic front view which shows the internal structure of the microscope apparatus which concerns on one embodiment of this invention.

Hereinafter, a microscope apparatus according to an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic plan view showing an internal configuration of a microscope apparatus 1 according to an embodiment of the present invention.

FIG. 2 is a schematic front view showing the internal configuration of the microscope apparatus 1.
The microscope apparatus 1 includes a halogen light source 2 and an LED light source 3 as a plurality of light sources, a mirror switching unit 4 as a light source switching unit having a half mirror 4a as an optical coupling unit and a mirror 4b as a light deflecting unit, and a plurality of units. A filter switching unit 5 as filter switching means having a filter 5a (only one is shown) and a control unit 6 connected to a control computer (not shown) are provided.

  Furthermore, the microscope apparatus 1 includes a housing 7, an AS (brightness stop, aperture stop) unit 8, an FS (field stop, field stop) unit 9, a polarizer switching unit 10, a cube switching unit 11, An AF (Auto-Focus) unit 12, an analyzer switching unit 13, an objective lens 14, a revolver 15, a revolver support member 16, lenses 17 and 18, and a DIC (Differential Interference Contrast) prism switching unit 19 Prepare.

  The halogen light source 2 is disposed on the right side surface of the housing 7, and the LED light source 3 is disposed on the back surface of the housing 7. It is assumed that the halogen light source 2 and the LED light source 3 are unitized and can be easily replaced with a xenon light source unit.

  In addition to the half mirror 4a and the mirror 4b, the mirror switching unit 4 includes a turret-type mirror holding portion 4c and an electric drive portion 4d such as a motor for rotating the mirror holding portion 4c. The mirror holding portion 4c includes three or more holes including a hole for holding the half mirror 4a, a hole for holding the mirror 4b, and a hole where the mirror is not held so as to allow light to pass (FIG. 2). Then, four holes are formed. The three or more holes are formed to be rotationally symmetric with respect to the rotation axis of the mirror holding portion 4c.

  The half mirror 4a is arranged so that the half mirror surface is located at a position where the optical axis of the halogen light source 2 and the optical axis of the LED light source 3 are orthogonal to each other, and transmits the light emitted from the halogen light source 2 and the LED. By deflecting the light emitted from the light source 3 by 90 degrees, the light emitted from the halogen light source 2 and the light emitted from the LED light source 3 are combined so as to be directed in the optical axis direction of the microscope. On the other hand, the mirror 4b deflects the light emitted from the LED light source 3 by 90 degrees and directs it in the direction of the optical axis of the microscope and shields the light from the halogen light source 2.

  The drive unit 4d of the mirror switching unit 4 moves the half mirror 4a or the mirror 4b on the optical path L under the control of the control unit 6, or retracts the half mirror 4a and the mirror 4b from the optical path L, that is, The mirror holding portion 4c is rotated so as to move the hole where the mirror is not held onto the optical path L.

  For example, when both the halogen light source 2 and the LED light source 3 are used as the observation light source, the mirror holding unit 4c rotates so as to move the half mirror 4a on the optical path L, and only the halogen light source 2 is used. Is rotated so as to move the hole where the mirror is not held on the optical path L, and when only the LED light source 3 is used, the mirror 4b is rotated so as to be moved on the optical path L.

  In order to prevent damage to the specimen due to ultraviolet light emitted from the halogen light source 2, an ultraviolet cut filter can be arranged on the mirror holding portion 4c. At that time, an ultraviolet cut filter may be disposed on the front surface or the back surface of the half mirror 4a, or a coat for directly shielding ultraviolet light may be formed on the back surface of the mirror surface. In addition, when a filter other than an ultraviolet cut filter, for example, an LBD (Light Balanced Daylight) filter, is used as the filter 5a of the filter switching unit 5 described later, the microscope can be observed with a color close to natural white.

  The filter switching unit 5 includes the plurality of filters 5a, a turret type filter holding unit 5b, and a driving unit 5c that rotates the filter holding unit 5b. The filter holding portion 5b is formed with a plurality of holes for accommodating the plurality of filters 5a so as to be rotationally symmetric with respect to the rotation axis of the filter holding portion 5b.

  As the filter 5a, for example, an LBD filter, an ultraviolet cut filter, or the like can be used. For example, when only the halogen light source 2 is used as an observation light source, an LBD filter or an ultraviolet cut filter is used. When only the LED light source 3 is used, a hole without a filter or an ultraviolet cut filter is used as the halogen light source 2 and the LED light source 3. Is used, the drive unit 5c rotates the filter holding unit 5b under the control of the control unit 6 so that the LBD filter, the ultraviolet cut filter, or the hole without the filter is positioned on the optical path L.

  As described above, the control unit 6 switches the filter 5a in accordance with the observation mode based on the usage state of the light source such as the halogen light source 2 or the LED light source 3, and the observation mode based on the user's filter switching operation. The filter 5a may be switched according to the above.

  An AS (brightness stop, aperture stop) unit 8 and an FS (field stop, field stop) unit 9 include a mirror switching unit 4, a lens 17, and a filter switching unit 5 for light emitted from the halogen light source 2 and the LED light source 3. It is arranged on the optical path L that has passed. Further, the AS unit 8 and the FS unit 9 are automatically controlled to a preset aperture diameter according to the selected objective lens 14 under the control of the control unit 6.

  The polarizer switching unit 10 is disposed on the optical path L of the light that has passed through the FS unit 9 and the lens 18. Further, the polarizer switching unit 10 includes a polarizer 10a, and moves the polarizer 10a on the optical path L during differential interference observation described later under the control of the control unit 6.

  The cube switching unit 11 is disposed on the optical path L of the light that has passed through the polarizer switching unit 10. The cube switching unit 11 includes a bright field cube 11a and a dark field cube 11b. Under the control of the control unit 6, the dark field cube 11b is used for dark field observation described later, and the bright field cube 11a is used for other observations. And move it on the optical path L.

  The DIC prism switching unit 19 is disposed in the revolver 15 on the optical path L of light deflected vertically (Z-axis) downward by the cube switching unit 11. The DIC prism switching unit 19 includes a DIC prism 19a, and moves the DIC prism 19a on the optical path L during differential interference described later under the control of the control unit 6.

  The revolver 15 is provided with a plurality of objective lenses 14. The revolver 15 is supported by a revolver support member 16. The revolver support member 16 moves up and down integrally with the objective lens 14 and the revolver 15 in the Z-axis direction.

  An AF unit 12 is disposed above the cube switching unit 11 in the Z axis, and an analyzer switching unit 13 is disposed further above the AF unit 12. The analyzer switching unit 13 includes an analyzer 13a, and moves the analyzer 13a onto the optical path L during differential interference observation described later.

  An eyepiece tube (not shown) may be directly installed above the Z axis of the analyzer switching unit 13 to observe the naked eye, or a TV camera adapter and a CCD camera may be installed to observe a microscope image via a TV monitor. It is possible.

Hereinafter, the operation of the microscope apparatus 1 according to the present embodiment will be described for each observation method.
<Bright field observation>
First, a specimen is placed on a stage (not shown) located below the microscope apparatus 1. The control unit 6 automatically operates the revolver 15 from information such as the observation magnification obtained in advance for the conveyed specimen, or the operator operates the operation lens (not shown) to operate the objective lens 14 at the time of observation. select.

Then, one or both of the halogen light source 2 and the LED light source 3 are turned on.
When both the halogen light source 2 and the LED light source 3 are turned on, the control unit 6 rotates the mirror holding unit 4 c by the drive unit 4 d of the mirror switching unit 4, and the light emitted from the halogen light source 2 and the LED light source 3 The half mirror 4a is moved to a position where the emitted light intersects.

  In this case, the half mirror 4a couples the light emitted from the halogen light source 2 and the light emitted from the LED light source 3 by transmitting the light emitted from the halogen light source 2 and deflecting the light emitted from the LED light source 3. To do. As a result, the wavelength characteristics of the light emitted from the halogen light source 2 and the wavelength of the light emitted from the LED light source 3 can be compensated for each other, and it is possible to observe a specimen defect that is difficult to observe with a single light source. Become. In addition, by combining light, it is possible to increase the luminance, or to omit the light source switching operation when observation with a single light source is not required.

  Next, when only the halogen light source 2 is turned on, the control unit 6 rotates the mirror holding unit 4 c by the drive unit 4 d of the mirror switching unit 4, and the mirror 6 is placed on the optical path L of the light emitted from the halogen light source 2. The hole of the holding part 4c where the mirror is not held is moved.

  When only the LED light source 3 is turned on, the control unit 6 rotates the mirror holding unit 4c by the drive unit 4d of the mirror switching unit 4, and the mirror 4b is placed on the optical path L of the light emitted from the LED light source 3. Move. In this case, the mirror 4b deflects the light emitted from the LED light source 3 by 90 degrees to guide the optical path L to the filter switching unit 5 side.

  As described above, the control unit 6 responds to an observation mode such as an observation mode based on a use state of a light source such as the halogen light source 2 or the LED light source 3, or an observation mode based on a user's filter switching operation in an operation unit (not shown). Thus, for example, the filter holding unit 5b is rotated by the drive unit 5c of the filter switching unit 5 so that the filter 5a such as an LBD filter, an ultraviolet cut filter, or a hole without a filter automatically moves on the optical path L. Let

  The light that has passed through the lens 17 and the filter switching unit 5 is guided to the cube switching unit 11 through the AS unit 8 and the FS unit 9 and the lens 18. The AS unit 8 and the FS unit 9 are automatically changed by the control unit 6 to a preset aperture diameter according to the objective lens 14. Further, the polarizer 10a of the polarizer switching unit 10 is retracted from the optical path L during bright field observation.

  In the cube switching unit 11, the bright field cube 11a is controlled to be positioned on the optical path L during bright field observation, and light is deflected downward by the bright field cube 11a. The DIC prism 19a of the DIC prism switching unit 19 is retracted from the optical path L during bright field observation, and the light deflected downward in the Z-axis is guided to the objective lens 14 and further positioned below the objective lens 14. Led to the specimen to do.

  The light reflected by the specimen is reflected upward in the Z axis, and is guided to an eyepiece tube (not shown) or a TV camera adapter and a CCD camera through the bright field cube 11a and the AF unit 12, and is observed. Note that the analyzer 13a of the analyzer unit 13 is retracted from the optical path L during bright field observation.

<Dark field observation>
Only differences from the bright field observation described above will be described.
When performing observation centering on dark field observation, it is preferable to replace the LED light source 3 as a light source, for example, by selecting a relatively high-brightness mercury xenon light source and exchanging it in advance. While the mercury xenon light source has high luminance, it has a drawback that it cannot be dimmed by variable voltage. Therefore, when mercury xenon is used instead of the LED light source 3, a neutral density filter (ND) is used as the filter 5a of the filter switching unit 5, for example, having a transmittance of 75%, 50%, 25%, etc. It is good to arrange a plurality.

In the cube switching unit 11, the dark field cube 11b is moved on the optical path L instead of the bright field cube 11a under the control of the control unit 6, and the specimen is observed in the dark field.
<Differential interference observation>
Only differences from the bright field observation described above will be described.

  By moving the polarizer 10 a of the polarizer switching unit 10, the analyzer 13 a of the analyzer switching unit 13, and the DIC prism 19 a of the DIC prism switching unit 19 onto the optical path L, the shape of the sample is given pseudo colors and unevenness. Observe.

  When observing the sample, the DIC prism 19a is finely adjusted in a plane (XY plane) orthogonal to the optical axis direction (Z-axis direction) of the objective lens 14, so that the color and brightness change, so that the sample can be easily observed. It is common to observe while looking for the position.

  For example, when a semiconductor bare wafer is used as a specimen, a defect inspection of a surface layer having a very low level may be required by differential interference observation. In the differential interference, the brightness changes by finely adjusting the DIC prism 19a as described above, but the most uneven and the most observable in contrast is the position where the DIC prism 19a is moved a little from the darkest state. I know that there is.

  Therefore, it may be effective to use a high-intensity light source even in the bare wafer inspection. Therefore, as the light source, a mercury xenon light source may be selected and replaced in advance instead of the LED light source 3, and both or one of the halogen light source 2 and the mercury xenon light source may be used properly.

  By the way, depending on the user's request, there may be realized a system in which the defect of the specimen based on the defect position information from the automatic defect inspection apparatus in the previous process is moved into the field of view of the microscope apparatus 1 and the defect image is automatically acquired. .

  In this case, using a control computer (not shown), it is possible to acquire an image while judging the contrast of the defect image each time through image processing. For example, the observation with the halogen light source 2 is set as a default, and when a defect can be confirmed without any problem by satisfying a preset contrast value, an image is acquired as it is, and when the defect cannot be confirmed, the halogen light source 2 is selected. It is also possible to acquire an image under the most contrasting conditions while selecting a ND filter or finely adjusting the DIC prism 19a by combining a mercury xenon light source or switching the halogen light source 2 to a mercury xenon light source.

<Line width measurement>
2. Description of the Related Art In recent years, a system has been constructed that measures the fine line width of a TFT (Thin Film Transistor) pattern based on a microscopic image in a liquid crystal substrate inspection, and feeds back exposure abnormality and layer overlay abnormality to the manufacturing process.

  In the line width measurement, the edge of the pattern in the microscope image is recognized by image processing. Therefore, the higher the contrast of the pattern edge, the better the measurement accuracy of the line width measurement. In the liquid crystal substrate, when a band-pass filter is inserted as the filter 5a of the filter switching unit 5, the contrast of the microscope image may change. Using the halogen light source 2 and the LED light source 3, there are several types of band-pass filters as the filter 5a. If prepared, line width measurement can be performed with high accuracy by a combination of one or two light sources having the highest contrast and a band-pass filter investigated in advance in the inspection process.

  In the present embodiment described above, it is possible to perform difficult observation with a single light source by combining light emitted from a plurality of light sources such as the halogen light source 2 and the LED light source 3. Therefore, according to the present embodiment, the observation performance can be improved.

  Further, in the present embodiment, the microscope apparatus 1 serves as a light source switching unit that moves the half mirror 4a to a position in the optical path L of light emitted from the halogen light source 2 and the LED light source 3 and a position retracted therefrom. A mirror switching unit 4 is provided.

  In the present embodiment, the microscope apparatus 1 includes a mirror 4b as a light deflecting unit that deflects light emitted from the LED light source 3 as at least one of a plurality of light sources, and the mirror switching unit 4 includes The half mirror 4a and the mirror 4b are selectively moved in the optical path L.

  With these configurations, in addition to observation using both the halogen light source 2 and the LED light source 3, observation using one of the halogen light source 2 and the LED light source 3 can be performed, and the observation performance can be further improved.

  Moreover, in this Embodiment, the microscope apparatus 1 is provided with the filter switching means 5 which moves the at least 1 of several filter 5a on the optical path L according to an observation aspect. Therefore, when both the halogen light source 2 and the LED light source 3 are used or when one of them is used, the optimum filter 5a can be automatically selected, and thus the observation performance can be further improved.

  In the present embodiment, two types of light sources, that is, a halogen light source 2 and an LED light source 3 are employed as a plurality of light sources. Therefore, the defects of the light source can be compensated for each other, and thus the observation performance can be further improved.

  Further, in the present embodiment, the half mirror 4a is adopted as an optical coupling means for coupling light emitted from the halogen light source 2 and the LED light source 3. Therefore, observation performance can be improved with a simple configuration.

  In this embodiment, the halogen light source 2 and the LED light source 3 are mainly described as examples of the light source. However, the above-described mercury xenon or infrared light source (for example, the halogen light source 2 is configured by removing the heat ray absorption filter). It is also possible to use other light sources, such as, and it is preferable to arrange them according to the desired observation or inspection.

  In the present embodiment, the example in which the light emitted from the halogen light source 2 and the light emitted from the LED light source 3 are combined has been described. However, for example, the light emitted from three or more light sources by increasing the number of half mirrors. The light emitted from two or more light sources using the same light source may be combined.

  In addition, a plurality of half mirrors 4a are installed in the mirror holding portion 4c, and wavelength selection filters such as dichroic filters, infrared cut filters, and ultraviolet cut filters are appropriately provided on the respective non-mirror surfaces of the half mirrors 4a. The filter switching means can be omitted by forming or by arranging the above-described various filters on either the front surface or the back surface.

DESCRIPTION OF SYMBOLS 1 Microscope apparatus 2 Halogen light source 3 LED light source 4 Mirror switching unit 4a Half mirror 4b Mirror 4c Mirror holding | maintenance part 4d Drive part 5 Filter switching unit 5a Filter 5b Filter holding | maintenance part 5c Drive part 6 Control part 7 Housing | casing 8 AS unit 9 FS unit DESCRIPTION OF SYMBOLS 10 Polarizer switching unit 10a Polarizer 11 Cube switching unit 11a Bright field cube 11b Dark field cube 12 AF unit 13 Analyzer switching unit 13a Analyzer 14 Objective lens 15 Revolver 16 Revolver support member 17, 18 Lens 19 DIC prism switching unit 19a DIC prism

Claims (6)

Multiple light sources;
An optical coupling means for coupling light emitted from the plurality of light sources;
A microscope apparatus comprising:   2. The microscope apparatus according to claim 1, further comprising light source switching means for moving the optical coupling means between a position in an optical path of light emitted from the light source and a position retracted therefrom. Further comprising light deflecting means for deflecting light emitted from at least one of the plurality of light sources,
The light source switching means selectively moves the light deflecting means and the optical coupling means in an optical path of light emitted from the light source;
The microscope apparatus according to claim 2. Multiple filters,
Filter switching means for moving at least one of the plurality of filters on an optical path of light emitted from the light source, depending on an observation mode;
The microscope apparatus according to any one of claims 1 to 3, further comprising:   The microscope apparatus according to any one of claims 1 to 4, wherein the plurality of light sources includes two or more types of light sources.   6. The microscope apparatus according to claim 1, wherein the optical coupling unit is a half mirror.