JP4487324B2 - Microscope equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a microscope apparatus, and more particularly to a microscope apparatus that can selectively use ultraviolet light and visible light as illumination light.
[0002]
[Prior art]
In recent years, the structure of semiconductor devices has been miniaturized. For example, in the case of 16M dynamic RAM, the line width is about 0.5 μm.
[0003]
In order to inspect a semiconductor device having such a fine structure, a microscope apparatus with high resolution is required.
[0004]
As one of the techniques for increasing the resolution, it is useful to use a light source having a short wavelength.
[0005]
By the way, visible light sources such as tungsten lamps and halogen lamps are generally known as light sources of conventional microscope apparatuses, but these light sources do not emit much ultraviolet light, and particularly the extreme ultraviolet having a wavelength of 300 nm or less. When light (DUV) is used, the amount of light necessary for observation cannot be secured.
[0006]
When ultraviolet light is required, a light source such as a mercury lamp is used, but the obtained image is only a monochrome image, and color information which is one of the important items for inspection cannot be obtained. Even in a microscope apparatus that can be observed with ultraviolet light, a microscope apparatus that can observe with visible light is required.
[0007]
However, it is difficult to use a common illumination system for ultraviolet light (particularly extreme ultraviolet light) and visible light. Therefore, the present invention is a microscope apparatus in which a visible light illumination system and an ultraviolet light illumination system are stacked on a common observation system, and visible light and ultraviolet light are separated by a dichroic mirror disposed in the observation system optical path. And was filed by the present applicant (Japanese Patent Application No. 9-224323).
[0008]
[Problems to be solved by the invention]
By the way, since extreme ultraviolet light is particularly harmful to the human body, a microscope apparatus using a light source of extreme ultraviolet light needs to have a configuration in which extreme ultraviolet light does not enter the eye through an eyepiece.
[0009]
However, since the dichroic mirror separates light by a predetermined wavelength selection characteristic, it is difficult to completely separate ultraviolet light and visible light.
[0010]
For example, when a laser or the like is used as an ultraviolet light source, the ultraviolet light may leak to the visible light observation system through the dichroic mirror.
[0011]
The present invention has been made in view of such circumstances, and the problem is that one of ultraviolet light and visible light can be selected as illumination light, and the ultraviolet light enters the visible light observation system when visible light is selected. It is an object of the present invention to provide a microscope apparatus that can reliably prevent the above.
[0012]
[Means for Solving the Problems]
In order to solve the above problem, a microscope apparatus according to claim 1 is a visible light observation system including an eyepiece for observing a sample illuminated with visible light, and an ultraviolet for observing the sample illuminated with ultraviolet light. In a microscope apparatus including a light observation system, when the visible light is selected as illumination light, the visible light is reflected and guided to the sample, and reflected light from the sample is guided to the visible light observation system. When the ultraviolet light is selected as illumination light, the second optical member reflects the ultraviolet light and guides it to the sample, and guides the reflected light from the sample to the ultraviolet light observation system. And when the visible light is selected as illumination light, an illumination light selection member that blocks incidence of the ultraviolet light to the visible light observation system, the second optical member and the illumination light selection member are , Each said ultraviolet Characterized in that the illumination optical path of a selectively positionable.
The microscope apparatus according to the second aspect of the invention includes a visible light illumination system that illuminates a sample with visible light, an ultraviolet light illumination system that illuminates the sample with ultraviolet light, and the illumination that is illuminated by the visible light illumination system. In a microscope apparatus provided with a visible light observation system including an eyepiece for observing a sample and an ultraviolet light observation system for observing the sample illuminated by the ultraviolet light illumination system, the visible light is selected as illumination light. When the ultraviolet light is selected as illumination light, the first optical member that reflects the visible light to the sample and guides the reflected light from the sample to the visible light observation system, A first illuminating light selection member for blocking incidence of visible light to the ultraviolet light observation system; and when the ultraviolet light is selected as illumination light, the ultraviolet light is reflected and guided to the sample, and the sample Reflection from A second optical member that guides the ultraviolet light to the ultraviolet light observation system, and a second illumination light selection member that blocks incidence of the ultraviolet light to the visible light observation system when the visible light is selected as illumination light; The first optical member and the first illumination light selection member can be selectively disposed in the visible light illumination system optical path, respectively, and the second optical member and the second illumination light selection Each of the members can be selectively disposed in the optical path of the ultraviolet illumination system.
[0013]
When the first optical member is disposed in the visible light illumination system optical path, the second illumination light selection member (illumination light selection member) can be disposed in the ultraviolet light illumination system optical path, and the second optical member is disposed in the ultraviolet light illumination system optical path. The first illumination light selection member can be disposed in the visible light illumination system optical path.
[0014]
A microscope apparatus according to a third aspect of the present invention is the microscope apparatus according to the second aspect , wherein when the first optical member is disposed in a visible light illumination system optical path, the second illumination light selection member is ultraviolet. The first illumination light selection member moves to the visible light illumination system optical path when the second optical member moves to the light illumination system optical path and the second optical member is arranged in the ultraviolet light illumination system optical path.
[0015]
The second illumination light selection member corresponding to the selected first optical member can be selected, and the first illumination light selection member corresponding to the selected second optical member can be selected.
[0016]
A microscope apparatus according to a fourth aspect of the present invention is the microscope apparatus according to the second aspect , wherein the first optical member and the second illumination light selection member are integrally formed, and the second optical member. And the first illumination light selection member are integrally formed.
[0017]
There is no need to individually drive the first optical member and the second illumination light selection member, and the second optical member and the first illumination light selection member, respectively, and the number of drive mechanisms and guides can be reduced. In the case of electric drive, the number of drive motors can be reduced.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0019]
1 and 2 are broken sectional views showing the microscope apparatus according to the first embodiment of the present invention, and FIG. 3 is a perspective view of a second hollow block arranged in the optical path of the ultraviolet light illumination system.
[0020]
1 shows a state when a visible light illumination system is selected as illumination light, and FIG. 2 shows a state when an ultraviolet light illumination system is selected as illumination light.
[0021]
This microscope apparatus includes a microscope main body 10, a lens barrel 30, an electric revolver 40, a stage 50, and an ultraviolet light detector 60.
[0022]
The microscope body 10 includes a base 10A, a support 10B, and an arm 10D.
[0023]
A lamp house incorporating a halogen lamp 22 is provided on the back side of the arm 10D. In addition, an ultraviolet image detection unit 10C is placed on the arm 10D. The ultraviolet image detection unit 10 </ b> C is configured to be detachable from the microscope body 10.
[0024]
The lens barrel 30 is attached to the upper part of the ultraviolet image detection unit 10 </ b> C and has an eyepiece 31.
[0025]
The ultraviolet light detector 60 is attached to the upper part of the ultraviolet image detection unit 10C and includes an ultraviolet light CCD.
[0026]
The electric revolver 40 is attached to the lower surface of the arm 10 </ b> D, and the electric revolver 40 holds a plurality of objective lenses 41 and 42. The objective lens 41 is for visible light, and the objective lens 42 is for ultraviolet light.
[0027]
The ultraviolet objective lens is used because it is difficult to correct aberrations appropriately for both visible light and ultraviolet light.
[0028]
The stage 50 is provided on the base 10 </ b> A and moves up and down along the optical axes of the objective lenses 41 and 42.
[0029]
In the ultraviolet image detection unit 10C, a mercury lamp 12, a UV filter 13, relay lenses 14, 15 constituting a relay optical system for ultraviolet light, a shutter 16, a half mirror 17, and a second hollow block 18 are arranged. .
[0030]
The shutter 16 is driven by a solenoid 16A, and is inserted into the ultraviolet illumination system optical path so that ultraviolet light does not enter the observation system optical path when performing visible light observation.
[0031]
The second hollow block 18 includes a total reflection mirror (second optical member) 18A and a light blocking body (second illumination light selection member , illumination light selection member ) 18B having a through hole 18C (see FIG. 3). ).
[0032]
The second hollow block 18 can move in a direction orthogonal to the optical path of the mercury lamp 12 (direction passing through the drawing).
[0033]
Therefore, either one of the total reflection mirror 18A and the light shield 18B can be arranged with respect to the ultraviolet light path.
[0034]
When the light shield 18B is arranged in the ultraviolet illumination system optical path, the central axis of the through hole 18C is located on the optical path of the visible light observation system.
[0035]
The second hollow block 18 is attached to the fixed guide portion 19 via a ball race mechanism that supports the plurality of balls 18 a in a rollable manner, and is movable with respect to the fixed guide portion 19.
[0036]
A rack 18D is formed on the upper part of the second hollow block 18, and this rack 18D is engaged with a pinion 20A fixed to a rotating shaft of a motor (for example, a DC motor) 20. The motor 20 is fixed to the fixed guide portion 19.
[0037]
A halogen lamp 22, relay lenses 24 and 25 constituting a visible light relay optical system, and a first hollow block 28 are arranged in the arm 10D.
[0038]
The first hollow block 28 includes a half mirror (first optical member) 28A and a light shielding body (first illumination light selection member) 28B having a through hole 28C.
[0039]
The first hollow block 28 can move in a direction orthogonal to the optical path of the halogen lamp 22 (direction passing through the drawing).
[0040]
Therefore, either one of the half mirror 28A and the light shielding body 28B can be arranged with respect to the visible light illumination system optical path.
[0041]
When the light shield 28B is disposed in the visible light illumination system optical path, the central axis of the through hole 28C is located on the optical path of the ultraviolet light observation system.
[0042]
The first hollow block 28 is attached to the fixed guide portion 29 via a ball race mechanism that supports the plurality of balls 28 a in a rollable manner, and is movable with respect to the fixed guide portion 29.
[0043]
A rack (not shown) is formed on the upper portion of the first hollow block 28, and this rack meshes with a pinion 26 </ b> A fixed to a rotating shaft of a motor (for example, a DC motor) 26. The motor 26 is fixed to the fixed guide portion 29.
[0044]
The dovetail formed on the lower surface of the ultraviolet image detection unit 10C or the dovetail groove formed on the upper surface of the arm 10D is engaged. The internal space of the ultraviolet image detection unit 10C and the internal space of the arm 10D communicate with each other through an opening S, and the optical path between the first hollow block 28 and the second hollow block 18 is communicated with the opening S. Is formed.
[0045]
When visible light is selected as illumination light, the motor 26 operates to place the half mirror 28A in the visible light illumination system optical path, and the motor 20 operates to move the light shield 18B to the ultraviolet light illumination system optical path. . At this time, the through hole 18C is disposed in the visible light observation system optical path.
[0046]
The illumination light emitted from the halogen lamp 22 is reflected by the half mirror 28 </ b> A and is irradiated onto a predetermined region on the sample 51 through the visible light objective lens 41. This illumination optical system is configured to achieve Koehler illumination on the sample 51.
[0047]
Reflected light from the sample 51 passes through the half mirror 28 </ b> A, passes through the opening S and the through-hole 18 </ b> C, is imaged by the imaging lens 23 in the lens barrel 30, and is observed by the eyepiece 31.
[0048]
At this time, since the illumination light from the mercury lamp 12 is blocked by the second illumination light selection member 18B and also by the shutter 16, the ultraviolet light is irradiated on the sample 51 and the visible light observation system. No (see Figure 1).
[0049]
When ultraviolet light is selected as illumination light, the motor 20 operates to place the total reflection mirror 18A in the ultraviolet light illumination system optical path, and the motor 26 operates to cause the light shield 28B to be in the visible light illumination system optical path. Move to. At this time, the through-hole 28C is disposed in the ultraviolet light observation system optical path.
[0050]
The illumination light emitted from the mercury lamp 12 passes through the UV filter 13 and becomes only illumination light that does not contain visible light.
[0051]
The illumination light passes through the half mirror 17 through the relay lenses 14 and 15 for ultraviolet light, and is polarized by the total reflection mirror 18A to the opening S, the through hole 28C, and the objective lens 42 for ultraviolet light, and a predetermined region on the sample 51. Is irradiated.
[0052]
This illumination optical system is configured to achieve Koehler illumination on the sample 51.
[0053]
The reflected light from the sample 51 passes through the through hole 28C and the opening S, is reflected by the total reflection mirror 18A, and is further guided by the half mirror 17 to the ultraviolet light detector 60.
[0054]
The light reflected by the half mirror 17 is imaged by the ultraviolet light imaging lens 21 and received by the ultraviolet light CCD of the ultraviolet light detector 60.
[0055]
The ultraviolet light received by the ultraviolet CCD is converted into an electrical signal, visualized by a monitor (not shown), and observed.
[0056]
At this time, since the illumination light from the halogen lamp 22 is blocked by the first illumination light selection member 28B, visible light is not irradiated to the sample 51 or the ultraviolet light observation system (see FIG. 2).
[0057]
According to this embodiment, even when switching between observation with visible light and observation with ultraviolet light is performed, ultraviolet light and visible light can be reliably separated. As a result, even if a light source of extreme ultraviolet light is used, there is no possibility that the extreme ultraviolet light enters the eye through the eyepiece.
[0058]
Even in the case of ultraviolet light observation, it is possible to prevent visible light from entering the ultraviolet light observation system and causing flare and ghost.
[0059]
4 and 5 are broken sectional views showing a microscope apparatus according to a second embodiment of the present invention. The same parts as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.
[0060]
4 shows a state when visible light is selected as the illumination light, and FIG. 5 shows a state when ultraviolet light is selected as the illumination light.
[0061]
In this embodiment, the second illumination light selection member (illumination light selection member) 18B is integrally formed on the upper part of the half mirror 28A, and the total reflection mirror 18A is integrally formed on the upper part of the first illumination light selection member 28B. In addition, the first hollow block 28 and the second hollow block 18 are integrated to form a two-story block 108, and this block 108 is driven only by the motor 26 of the arm 10D. This is different from the first embodiment.
[0062]
According to this embodiment, the same effects as those of the first embodiment can be obtained.
[0063]
In addition, since it is not necessary to drive the first hollow block 28 and the second hollow block 18 separately, only one motor, rack, guide, etc. are required even in the case of electric drive, and the configuration is simple. An inexpensive apparatus can be obtained.
[0064]
In each of the above embodiments, the first hollow block and the second hollow block are motor-driven, but may be moved manually.
[0065]
The first hollow block 28 integrally forms the half mirror 28A and the light shielding body 28B, but the half mirror 28A and the light shielding body 28B may be separated.
[0066]
Furthermore, although the total reflection mirror 18A and the light shielding body 18B are integrally formed in the second hollow block 18, the total reflection mirror 18A and the light shielding body 18B may be separated.
[0067]
In each of the above embodiments, the ultraviolet light illumination system is disposed above the visible light illumination system. However, the visible light illumination system may be disposed above the ultraviolet light illumination system. At this time, the ultraviolet light detector 60 is attached to the side surface of the arm 10D.
[0068]
Further, in each of the above embodiments, a mercury lamp is used as an ultraviolet light source. However, in the case of a mercury lamp, in the case of ultraviolet light, particularly extreme ultraviolet light, it is difficult to obtain a sufficient amount of light necessary for observation. Alternatively, laser light for irradiating extreme ultraviolet light may be used as the light source.
[0069]
In addition, although the ultraviolet image detection unit 10C and the arm 10D are configured to be separable, each unit may be integrated as long as visible light and ultraviolet light are completely separated.
[0070]
【The invention's effect】
As described above, according to the microscope apparatus of the first aspect of the present invention, it is possible to reliably prevent ultraviolet light from entering the optical path of the visible light observation system when visible light is selected as illumination light.
[0071]
According to the microscope apparatus of the second aspect of the present invention, the switching operation of the illumination light is facilitated and an erroneous operation can be prevented.
[0072]
According to the microscope apparatus of the third aspect of the present invention, the switching operation of the illumination light is facilitated, and erroneous operations and malfunctions can be prevented. In addition, the configuration can be simplified, and the manufacturing cost can be reduced.
[Brief description of the drawings]
FIG. 1 is a broken sectional view showing a microscope apparatus according to a first embodiment of the present invention, and shows a state when a visible light illumination system is selected as illumination light.
FIG. 2 is a broken sectional view showing the microscope apparatus according to the first embodiment of the present invention, and shows a state when an ultraviolet light illumination system is selected as illumination light.
FIG. 3 is a perspective view of a second hollow block.
FIG. 4 is a broken sectional view showing a microscope apparatus according to a second embodiment of the present invention, and shows a state when visible light is selected as illumination light.
FIG. 5 is a broken sectional view showing a microscope apparatus according to a second embodiment of the present invention, and shows a state when ultraviolet light is selected as illumination light.
[Explanation of symbols]
18A Total reflection mirror (second optical member)
18B light shield (second illumination light selection member , illumination light selection member )
28A half mirror (first optical member)
28B light shield (first illumination light selection member)
51 samples

Claims (4)

In a microscope apparatus comprising a visible light observation system including an eyepiece for observing a sample illuminated with visible light, and an ultraviolet light observation system for observing a sample illuminated with ultraviolet light,
When the visible light is selected as illumination light, the first optical member that reflects the visible light to the sample and guides the reflected light from the sample to the visible light observation system;
When the ultraviolet light is selected as illumination light, the second optical member that reflects the ultraviolet light and guides it to the sample, and guides the reflected light from the sample to the ultraviolet light observation system;
When the visible light is selected as the illumination light, an illumination light selection member that blocks incidence of the ultraviolet light to the visible light observation system,
The microscope apparatus, wherein the second optical member and the illumination light selection member can be selectively disposed in the illumination light path of the ultraviolet light, respectively. A visible light illumination system that illuminates the sample with visible light; an ultraviolet light illumination system that illuminates the sample with ultraviolet light; and a visible light observation system that includes an eyepiece that observes the sample illuminated by the visible light illumination system; In a microscope apparatus comprising an ultraviolet light observation system for observing the sample illuminated by the ultraviolet light illumination system,
When the visible light is selected as illumination light, the first optical member that reflects the visible light to the sample and guides the reflected light from the sample to the visible light observation system;
When the ultraviolet light is selected as the illumination light, a first illumination light selection member that blocks incidence of the visible light to the ultraviolet light observation system;
When the ultraviolet light is selected as illumination light, the second optical member that reflects the ultraviolet light and guides it to the sample, and guides the reflected light from the sample to the ultraviolet light observation system;
When the visible light is selected as the illumination light, the second illumination light selection member that blocks the incidence of the ultraviolet light to the visible light observation system,
The first optical member and the first illumination light selection member can be selectively disposed in the visible light illumination system optical path, respectively.
The microscope apparatus, wherein the second optical member and the second illumination light selection member can be selectively disposed in the ultraviolet illumination system optical path, respectively. When the first optical member is disposed in the visible light illumination system optical path, the second illumination light selection member moves to the ultraviolet light illumination system optical path,
3. The microscope apparatus according to claim 2, wherein when the second optical member is disposed in the ultraviolet illumination system optical path, the first illumination light selection member moves to the visible illumination system optical path. The first optical member and the second illumination light selection member are integrally formed,
The microscope apparatus according to claim 2, wherein the second optical member and the first illumination light selection member are integrally formed.

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