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We claim:
1. A method of making an aperture mask for passing spectral phenomena
having a wavelength greater than the diameter of the mask aperture,
comprising:
depositing by vapor deposition a support layer on the bottom surface of a
thin substrate, said substrate having a central opening sufficiently large
to encompass all of the apertures of said aperture mask, said support
layer spanning said central opening;
depositing by vapor deposition a resist layer on the top surface of said
thin substrate and on the top surface of said support layer in the area of
said central opening, whereby said resist layer spans said central
opening;
removing said support layer, whereby said resist layer is self-supporting
over said central opening;
producing by electron beam etching at least one aperture through said
resist layer within the area of said central opening, each said aperture
having a diameter of less than about 500 .ANG.;
depositing by vapor deposition to a thickness of about 500 .ANG. a first
metal layer on the bottom surface of said thin metal support and on the
bottom surface of said resist layer exposed within the area of said
central opening, said first metal layer having apertures corresponding to
the apertures formed in said resist layer; and
removing said resist layer to provide a free-standing optically opaque mask
having at least one aperture.
2. The method of claim 1, further including depositing by vapor deposition
a second metal layer on the top surface of said thin substrate and on the
top surface of said first metal layer exposed within the area of said
central opening, said second metal layer having apertures corresponding to
the apertures formed in said resist layer.
3. Apparatus for optically reproducing a stencil pattern having feature
dimensions less than the wavelength of incident light, comprising:
a support table;
sample means on said table, said sample means comprising a substrate having
a thin photoresist layer;
a source of incident light;
an aperture mask carrying a stencil pattern to be reproduced, said pattern
including features having dimensions less than the wavelength of said
incident light; and
means mounting said aperture mask between said source of light and said
photoresist layer so that said light passes through said pattern to said
photoresist layer, said layer being within the near field of light passing
through said pattern, whereby said pattern is replicated in said
photoresist layer.
4. The apparatus of claim 3, wherein said source of light is mounted to
simultaneously illuminate the entire pattern of said mask.
5. The apparatus of claim 5, wherein said aperture mask includes a
substrate having a large central opening and a thin film deposited over
said central opening, said thin film including at least one aperture
having a diameter less than 1/10 the wavelength of said incident light.
6. The apparatus of claim 5, wherein said source of light comprises a
source of visible light.
7. A method of optical lithography, comprising:
providing a source of visible light;
mounting on a support a substrate having a thin photoresistive layer;
locating an aperture mask between said source of visible light and said
photoresistive layer, said aperture mask having a pattern to be
reproduced, said pattern including at least one aperture having a
dimension less than the wavelength of said visible light;
positioning said aperture mask sufficiently close to the surface of said
photoresistive layer that substantially all of said layer lies within the
near field of light passing through said pattern of said aperture mask;
directing said visible light through said aperture mask to expose said
photoresist layer to thereby replicate said aperture mask pattern in said
photoresistive layer.
8. The method of claim 7, further including simultaneously illuminating all
apertures in said aperture mask to replicate the entire pattern to be
reproduced at one time.
9. A method of optical lithography, comprising:
forming a thin film aperture mask having a pattern to be reproduced which
includes at least one aperture having at least one dimension of less than
the wavelength of visible light in the plane of the surface of the thin
film;
forming a thin photoresistive layer on a substrate;
locating said aperture mask between a source of visible light and said
photoresistive layer;
positioning said aperture mask sufficiently close to the surface of said
photoresistive layer that substantially all of said layer lies within the
near field of light passing through said aperture mask; and
directing visible light through the apertures in said aperture mask formed
by said pattern to be reproduced to expose said photoresistive layer to
thereby replicate in said layer the size and shape of the apertures
forming said aperture mask pattern.
10. A method of making an aperture mask for passing spectral phenomena
having a wavelength greater than the diameter of the mask aperture,
comprising:
depositing by vapor deposition a support film on the bottom surface of a
thin substrate, said substrate having a central opening sufficiently large
to encompass the entire aperture-containing area of said aperture mask,
said film spanning and being self-supporting across said central opening;
depositing by vapor deposition a resist layer on the top surface of said
thin substrate and on the top surface of said support film within the area
of said central opening, whereby said resist layer is supported by said
film and spans said central opening;
removing said support film to leave said resist layer spanning, and being
self supporting over, said central opening;
producing by electron beam etching at least one aperture through said
resist layer within the area of said central opening, each said aperture
having a diameter of less than about 500 .ANG.;
depositing by vapor deposition to a thickness of about 500 .ANG. a first
masking layer on the top surface of said resist layer, said masking layer
having an aperture corresponding to each aperture formed in said resist
layer to produce an aperture mask; and
removing said resist layer within the area of said central opening to leave
said masking layer spanning said central opening.
11. The method of claim 10, wherein the step of depositing a first masking
layer comprises depositing a metal layer.
12. The method of claim 10, wherein the step of depositing a masking layer
comprises depositing an optically opaque dielectric material of small
grain size.
13. A method of making an aperture masking for passing spectral phenomena
having a wavelength greater than the diameter of the masking aperture,
comprising:
depositing by vapor deposition a support layer on the bottom surface of a
thin substrate, said substrate having a central opening sufficiently large
to encompass the entire aperture area of said aperture mask, said support
layer spanning said central opening;
depositing by vapor deposition a metal film layer on the top surface of
said thin substrate and on the top surface of said support layer in the
area of said central opening, whereby said metal film spans said central
opening;
depositing a resist film of less than about 500 .ANG. thickness onto the
top surface of said metal film layer;
etching at least one aperture of less than about 500 .ANG. diameter in said
resist film;
removing the metal film material exposed through each said resist film
aperture to produce a hole in said metal film layer corresponding to each
said resist film aperture;
removing said resist film from said metal film layer, leaving a
free-standing opaque metal film layer having at least one aperture of less
than about 500 .ANG. diameter within said central opening.
14. Apparatus for optically reproducing a stencil pattern, comprising:
a substrate carrying a thin photoresist layer;
a source of visible light;
an aperture mask carrying a stencil pattern to be reproduced, said pattern
including apertures having dimensions on the order of 1/10 the wavelength
of said visible light;
means mounting said aperture mask between said source of light and said
photoresist layer, so that light from said source passes through said
pattern apertures and exposes said photoresist layer, said aperture mask
being so located that said photoresist layer lies in the near field region
of said aperture mask so that light passing through said pattern apertures
strikes said photoresist layer to expose areas of said photoresist layer
equal to the size and shape of said pattern apertures to thereby replicate
said pattern.
15. The apparatus of claim 14, wherein said photoresist layer has a
thickness substantially equal to the extent of said near field region of
said aperture mask, whereby said light exposes substantially the entire
thickness of said photoresist material.
16. The apparatus of claim 14, wherein said pattern includes at least one
aperture having a width of less than about 500.ANG., and wherein visible
light passing through said at least one aperture retains the width and the
geometrical shape of said aperture within the near field region of said
aperture mask for accurate reproduction of the width and geometrical shape
of said at least one aperture.
17. The apparatus of claim 14, wherein said source of light illuminates the
entire aperture mask at one time for rapid exposure of the entire stencil
pattern onto said photoresist layer. |
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Claims |
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Description |
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BACKGROUND OF THE INVENTION
The present invention relates, in general, to high resolution optical
systems, and more particularly to a method and apparatus for the
production and use of light beams having diameters in the range of 100 to
500 .ANG.. The invention further relates to optical microscopes having a
resolution on the order of 500 .ANG., to methods of studying objects using
such a microscope, and to methods of lithography utilizing the high
resolution capabilities of the apparatus of the present invention.
With the advance of submicron technology, the need for a light microscope
for use in microanalysis of materials has steadily increased. Although
electron microscopes are capable of detecting objects with a very high
degree of resolution, viewing by this means not only requires that the
sample be inserted into a vacuum, but often results in destructive effects
on the sample because of the ionizing radiation.
With presently available technology, nondestructive viewing can be obtained
using visible light in two different ranges. At the lower end of the
scale, fluorescence spectroscopy coupled with chemical methods can be used
to determine on a statistical basis the dimensions between objects that
are up to about 80 .ANG. apart. At the upper end of the scale, light
microscopy, when used in the fluorescence mode, can be used to determine
dimensions as small as about one-half the wavelength of the light that is
used; that is, down to about 2500 .ANG.. However, separations between
objects (or feature dimensions) of between 80 .ANG. and 2500 .ANG. are
inaccessible using visible wave lengths. The ability to determine such
dimensions using light microscopy is very important since, unlike electron
microscopy, samples can be studied in their natural environment without
resorting to high vacuum conditions and without the risk of damage. Such a
capability is particularly useful in biological applications where
clinical testing or chemical mapping are to be done.
Advances in microelectronics are leading to smaller and smaller structures.
However, the techniques for fabricating such devices have not kept pace
with such developments, and the volume production of microscale devices
presents a difficult problem. Optical lithography is, at the present time,
limited to the production of features having a size of approximately 1
micron (10000 .ANG.), although improvements using far ultraviolet
radiation allows sizes down to one-half micron (5000 .ANG.) to be
achieved. To fabricate structures with even smaller sizes, one must resort
to electron, ion, or X-ray beam technology.
Although electron and ion beam technology are now the most widely used
methods in the microelectronics industry for producing submicron
structures, such methods have a relatively low rate of production due to
the need to scan the beam across the wafer on which the structure is being
formed. X-ray methods are being investigated since a larger production
rate may be achievable, although such methods require a dedicated
synchrotron source. An extension of optical technology to the half micron
size scale would couple the small feature size capability of electron,
ion, and X-ray beam technology to the higher rates which are necessary for
economical production.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a method and apparatus
for producing and using light beams having a diameter on the order of 500
.ANG..
It is another object of the present invention to overcome the disadvantages
of prior optical devices through the provision of a light microscope
capable of measuring objects having separations of between about 80 .ANG.
and 2500 .ANG..
It is a further object of the present invention to provide a visible light
microscope having a resolution of better than 500 .ANG., using visible
light.
It is another object of the present invention to provide an apparatus for
measuring feature dimensions with a resolution of less than about 500
.ANG., using visible light.
It is still another object of the present invention to provide a method of
fabricating a light aperture mask having feature dimensions on the order
of less than or about 500 .ANG..
A still further object of the present invention is to provide a method of
patterning materials to produce feature dimensions on the order of 500
.ANG. or less, using visible light.
The present invention is based on the discovery that visible radiation can
be transmitted in useful amounts through apertures which are on the order
of 1/16 of the wavelength of the incident radiation, and that when the
aperture is within the near field of an object from which the radiation
emanates, the radiation passing through the aperture will be the geometric
projection of that aperture. This feature is essentially independent of
the wavelength of the incident light, resulting in significant
consequences in the field of optics and, more particularly, to both light
microscopy and lithography.
Accordingly, it is another object of the present invention to provide a
method of optical lithography wherein feature sizes of less than 1/10 the
wavelength of visible radiation can be produced using the rapid
replication rates of optical techniques while obtaining the high
resolution normally available only with electron and ion beam methods.
It is an additional object of the invention to provide a scanning optical
microscope with a spatial resolution of 1/10 the wavelength of the
incident light to provide time-resolved chemical analysis and mapping
without the need for the sample to be placed in a vacuum.
It is another object of the invention to provide a scanning optical
microscope which may be used for spatial and chemical characterization of
an object at the level of resolution of a scanning electron microscope,
but without the need for vacuum handling and without the destructive
effects of electron beams.
In order to accomplish optical lithography and microscopy for feature
dimensions on the order of less than 1/10 the wavelength of the incident
light, the observation of light transmission through apertures having
similar diameters has to be coupled with a knowledge of the near field
radiation patterns produced by light passing through a small aperture.
When an aperture is very close to or in contact with a lithographic
substrate (to which the pattern of the aperture is to be applied), or is
very close to or in contact with an object to be imaged, the radiation
field through the aperture is the geometric projection of the aperture
shape. If the object (or substrate) is moved away from the apertures, the
radiation pattern produced by light passing through the aperture becomes
more diffuse as a result of the changing angular distribution of the
radiation. This diffusion occurs in what is known as the Fresnel region.
Eventually, as the object is moved further away, a distance is reached
where the angular distribution of the radiation pattern becomes constant
as a function of distance, so that further motion does not change the
shape or size of the pattern. This is known as the far field of the light
pattern.
Between the point of contact of the aperture with the object, and the
beginning of the Fresnel region, the angle of the radiation pattern is
relatively constant, and light passing through the aperture essentially
projects its shape. This region is known as the "near field", and extends
for a distance of about 1000 .ANG. from the surface of the aperture mask.
Although this near field phenomenon had previously been demonstrated using
microwave radiation passing through an aperture, it has not previously
been possible to confirm the existence of such a phenomenon using optical
wavelengths because of the inability to fabricate structures having
apertures with diameters on the order of 1/10 to 1/16 the wavelength of
the incident light.
As will be described hereinbelow, applicants have now constructed an
aperture plate incorporating apertures having diameters on the order of
300 .ANG., and have demonstrated that visible light can pass through such
apertures, independently of the wavelength of the light. An important
aspect of this light transmission is the relatively high transmission
obtained, which was sufficient to obtain detectable amounts of light using
an ordinary microscope illuminator lamp as the source.
The foregoing principles lead to two important applications. First, if a
stencil pattern with 300 .ANG. to 500 .ANG. feature sizes is used in place
of an aperture mask, and a substrate covered with a very thin layer of
photoresist is placed in the near field region of light passing through
the pattern, the entire stencil pattern can be imprinted onto the resist
with a very high degree of accuracy, since in the near field region, the
light pattern retains the geometric shape of the aperture. This allows
optical lithography with feature sizes as small as 300 .ANG. independent
of the wavelength of the incident radiation. Secondly, the same
fundamental principles apply to the imaging of an object through the use
of scanning techniques. Specifically, spectral phenomena produced by
illuminating an object also exhibits the near-field radiation pattern, in
that the spectral phenomena will be essentially perpendicular to the
surface from which it emanates within the near field region of the
surface. The spectral phenomena thus is essentially collimated in the near
field, permitting observation of a field of view which is limited to the
projected area of the aperture on the surface being observed, as long as
the aperture is in the near field. The spectral phenomena passing through
the aperture can then be recorded in the far field where an image of the
object can be formed if the aperture or an aperture array is scanned in a
raster-like fashion relative to the object. Such a scanning optical system
will have a spatial resolution limited by the aperture diameter instead of
by the wavelength of the incident light or of the spectral phenomena
emanating from the surface, and thus will have a resolution on the order
of 1/10 the wavelength.
In one aspect of the present invention, then, a visible light microscope is
provided which incorporates an aperture plate having at least one aperture
with a diameter of less than about 500 .ANG.. The aperture plate is an
optically opaque metal or dielectric film secured in a holder, and is
movable with respect to the object to be studied. A suitable transducer,
capable of moving the aperture plate in steps of about 100 .ANG., is used.
Alternatively, the object, or sample, which is to be observed by the
microscope may be moved relative to the aperture. Piezoelectric
manipulators capable of moving an object in steps on the order of 100
.ANG. are readily obtained commercially.
The microscope further includes at least one source of light which is to be
projected at the surface to be viewed. A collimated, intense source of
light is needed, and lasers provide a suitable source; however, other
sources of light also may be suitable. The incident light beam stimulates
the sample material, causing it to emit light by fluorescence,
surface-enhanced Raman scattering, resonance Rayleigh scattering, or other
phenomena. The aperture plate is close to or in contact with the surface
of the sample being measured, so that the emitted spectroscopic phenomena
pass into the aperture or apertures in the plate in the near field.
If the aperture plate is positioned within the near field of the surface of
the sample, spectral phenomena emanating from the surface area
corresponding to the aperture will pass through the aperture. The aperture
plate must be sufficiently thin as to be fully transparent to the spectral
phenomena where there is an aperture, so that the aperture wall does not
interfere with the light, but it must be thick enough to be opaque where
there is no aperture. A thickness of about 500 .ANG. is used. The signal
emerging from the side of the aperture not in contact with the sample may
be detected in the far field by means of a spectrograph and is analyzed by
means of an optical multi-channel analyzer. The aperture is scanned over
the sample in steps, so that a spectral map of the sample is processed and
may be displayed on a two dimensional digital display.
An important aspect of the present invention is that by maintaining contact
or near contact between the aperture plate and the surface of the sample,
and by providing a plate thickness of about 500 .ANG., the spectral
phenomena emitted from the aperture remain in a near field condition. This
maintains the spatial information which would be lost if the emitted light
or other spectral signal was in a far field condition relative to the
aperture. Although the light signal collected by an objective lens on the
side of the aperture plate farthest away from the sample is in the far
field, that does not affect the ability of the device to maintain the
spatial information once the signal has passed through the aperture.
In one embodiment of the invention, the light which is projected at the
surface to be viewed comprises a beam, for example from a laser, which
strikes the surface of the sample at a grazing angle of incidence; i.e.,
substantially tangentially with respect to that surface. The angle of
incidence is such as to create an evanescent field approximately 800.ANG.
deep in the material, the exact depth depending on the angle of incidence
and the material being studied. The evanescent field results in the
production of spectroscopic phenomena which may be observed through the
aperture, as described above. The angle of incidence of the laser may be
varied to produce different levels of evanescence in the sample. When the
sample is excited to different depths, the differences in spectra obtained
thereby may be compared to provide three-dimensional surface information
concerning the sample such as, for example, the chemical distribution
within the sample.
Where the sample material is transparent to the incident light, the light
source may be directed toward the bottom surface of the sample holder,
with the light passing into the sample and producing the desired
evanescent effect. Such an arrangement may be particularly suitable for
spectroscope studies of living materials such as bacteria, viruses and the
like. In still another embodiment, the light may be directed downwardly
onto the surface of the sample, passing through the viewing aperture
before striking the sample material, exciting that material to produce
spectral phenomena which then pass through the aperture for observation.
For extremely low light levels produced, for example, from small
concentrations of a sample, a single aperture in the aperture plate is
inefficient, since the input light source illuminates at least 100 times
the area being viewed by a single aperture at any given time. With a
single aperture, only a small percentage of the available information can
be collected, and this reduces the signal-to-noise ratio of the
measurements. This problem can be overcome by the use of Hadamard
Transform Imaging methods which allow retrieval of a two-dimensional
spatial image by measuring the intensities that pass through a binary
coded mask at different positions of the mask. With such methods, a
suitable mask would include multiple apertures each of less than or about
500 .ANG. in diameter arranged in a binary coded array, the multiple
aperture mask being used in place of the single aperture mask and being
illuminated by spectral signals emitted from the sample. The encoded
regions are either opaque or transparent to visible light, and when the
mask is moved in very small steps, measurements are taken of the intensity
pattern produced by the mask in each position. These light patterns can
then be decoded to recover the spatial distribution of the light over the
sample, thereby permitting a two-dimensional measurement of the sample.
The optical system of the present invention thus provides an optical
microscope having a spatial resolution which approaches that of a scanning
electron microscope, but which is completely non-destructive, allows a
sample to be viewed in situ without the need for placing it in a vacuum,
and provides chemically selective viewing of the sample. Furthermore,
since the aperture allows the passage of light with a substantial
intensity, measurements do not require a long time period, and thus the
formation of timeresolved images is possible. No other existing
microscopic probe has all of these features. Furthermore, the optical
system of the invention permits optical lithography having feature sizes
as small as 300 .ANG. independent of the wavelength of the incident
radiation, thereby permitting high replication rates with high resolution,
and providing a significant advance in micro-fabrication technology.
BRIEF DESCRIPTION OF THE DRAWINGS
The foregoing and additional objects, features and advantages of the
present invention will become apparent from a consideration of the
following detailed description of preferred embodiments thereof, taken in
conjunction with the accompanying drawings, in which:
FIG. 1 is a light micrograph recorded in the far field and showing light
transfer through apertures, and electron micrographs of the same
apertures;
FIG. 2 is a partial diagrammatic illustration of a light microscope
incorporating the present invention;
FIG. 3 is an enlarged sectional view of a portion of the microscope of FIG.
2, illustrating one embodiment of the invention;
FIG. 4 is a diagrammatic top plan view of an aperture mask suitable for use
in the present invention;
FIG. 5 is an enlarged sectional view of a portion of the microscope of FIG.
2, illustrating a second embodiment of the invention which utilizes the
aperture mask of FIG. 3;
FIG. 6 is a partial top plan view of a modified form of the aperture mask
of FIG. 4;
FIG. 7 is an enlarged sectional view of a portion of the microscope of FIG.
2, illustrating a third embodiment of the invention;
FIG. 8 is an enlarged sectional view of a portion of the device of FIG. 5,
modified for use in lithography;
FIGS. 9a through 9f are diagrammatic illustrations of the steps in a first
process for making an aperture mask for use in the devices of the present
invention;
FIGS. 10a through 10b are diagrammatic illustrations of the steps in a
second process for making an aperture mask in accordance with the present
invention; and
FIGS. 11a through 11e are diagrammatic illustrations of the steps in a
third process for making an aperture mask.
DESCRIPTION OF PREFERRED EMBODIMENTS
The present invention rests, in large measure, on the fundamental principle
that light will in significant quantities pass through an aperture having
a diameter which is substantially smaller than the wavelength of the light
to be transmitted. That light will pass through such an aperture in
significant and detectable quantities is demonstrated in the micrograph of
FIG. 1, which illustrates an aperture plate 10 carrying a first set of
apertures 12, 14, 16 and 18, and a second, duplicate, set of apertures
12', 14', 16' and 18'. Each of the pairs of apertures 12, 12', etc. are
separated by six micrometers. The first set of apertures 12, 14, 16 and 18
are 2400 .ANG., 1200 .ANG., 640 .ANG. and 320 .ANG. in diameter,
respectively, to within ten percent accuracy, and the second set is the
same. Electron micrographs 20, 22, 24 and 26 were obtained by an electron
scanning microscope to obtain exact measurements of the apertures 12, 14,
16 and 18, respectively, confirming not only their rectangular shape, but
their size.
In making the micrograph illustrated in FIG. 1, the aperture plate 10 was
illuminated with visible light, and light passing through the apertures
was recorded in the far field by conventional optical means. The
micrograph clearly illustrates that significant amounts of visible light
pass through an aperture of 320 .ANG. (32 nm). It is noted that the light
source was an ordinary tungsten microscope illuminator, but similar
results are obtained with other light sources, demonstrating that the
passage of light through such apertures is not dependent on the wavelength
of the light.
A scanning microscope utilizing the principles of the present invention is
illustrated diagrammatically at 30 in FIG. 2, to which reference is now
made. The basic components of the microscope are conventional, and include
adjustable optics indicated generally at 32 and incorporating an objective
lens housing 34, focusing means 36 for adjusting the position of the
housing along its horizontal axis, a stage 38 surrounding the end of the
objective lens housing and positionable by a micrometer 39, and an object
support 40 mounted on the microscope frame 42 by means of a coarse
positioning mechanism, generally indicated at 44.
The positioning mechanism 44 incorporates a first horizontally adjustable
carrier 46 which is movable in a horizontal plane along the longitudinal
axis of the lens contained in housing 34 and is mounted for accurate
positioning by a suitable X-axis micrometer 48. A second horizontally
adjustable carrier 50, is movable along an axis perpendicular to the
longitudinal axis of the lens and is positionable by a second, Y-axis,
micrometer 52. A vertically movable carrier 54 moves in a direction
perpendicular to the longitudinal axis of the lens in housing 34, and is
adjustable by means of a third, Z-axis, micrometer 56.
The adjustable object support 40 is mounted on the vertically movable
carrier 54 which is, in turn, mounted on the two horizontally movable
carriers 46 and 50 so that the object to be viewed by the microscope is
movable orthogonally along X, Y and Z axes for positioning with respect to
the objective lens in housing 34. The object to be viewed, or sample
material, is mounted on a support table 58 which is carried on
conventional piezoelectric scanners such as scanner 60 affixed to the
support. The scanners are controllable by means of control signals
supplied by way of cable 62 in known manner to cause the table 58 to be
moved in a stepwise fashion in very small increments to permit fine
positioning of the object and/or optical scanning thereof. Piezoelectric
manipulators capable of moving the object in steps of approximately 100
.ANG. are commercially available.
The illustrated scanner 60 responds to a control voltage to move the table
58 incrementally along the longitudinal, or X-axis, the extent of the
motion depending upon the amplitude of the applied voltage. Because the
piezoelectric scanner is capable of extremely small steps, the location of
the sample material with respect to the lens housing 34 can be determined
with great accuracy.
Although only a single incremental scanner 60 is illustrated in FIG. 1, it
will be understood that in the preferred embodiment of the invention,
three orthogonally-related piezoelectric scanners, or their equivalent,
would be utilized to permit movement of the object support table 58 along
the X, Y and Z axes. The manner of mounting and controlling such
transducers is well known and does not constitute part of the present
invention.
The conventional microscope illustrated in FIG. 2 and described hereinabove
provides the support structure for the present invention. In order to
carry out the inventive concepts, a source 64 of high intensity light is
required and may be suitably mounted on the microscope base. The source 64
is shown as being mounted on the support frame member 66, but it may be
mounted on a separate platform (not shown), if desired. In similar manner,
suitable viewing optics or measuring instruments, such as a spectrograph
(see FIG. 3) also are mounted on the microscope frame, for example on a
mounting bracket 68 aligned with the optical axis of lens 14.
Although any intense source of visible light may be used, a particularly
suitable source is a conventional laser.
As illustrated in FIG. 3, an object to be studied, or a sample material, 70
may be secured to the surface of the support table 58 which is, in turn,
carried by the piezoelectric scanner 60. The sample material may be a
polymer, a semiconductor array, a protein, a cell, a virus, bacteria, or
any other material desired to be studied through the use of a light
microscope with high resolution. The objective lens housing 34 includes a
cylindrical wall 72 and a nosepiece 74 adapted to carry an aperture ring
76 which supports an aperture mask 78. The mask, which will be described
in greater detail hereinbelow, is shown | | |
