Radiant energy – Inspection of solids or liquids by charged particles
Reexamination Certificate
1998-08-19
2001-06-05
Anderson, Bruce C. (Department: 2881)
Radiant energy
Inspection of solids or liquids by charged particles
C250S297000, C250S442110
Reexamination Certificate
active
06242737
ABSTRACT:
BACK GROUND OF THE INVENTION
The present invention relates to a microscopic system which can combine an electron microscope and a scanning probe microscope, especially a scanning tunneling microscope, by which it becomes possible to make a simultaneous observation of a specimen by mentioned two different types of microscope in ultra high vacuum condition.
DESCRIPTION OF THE PRIOR ART
In general, as a method to install a scanning tunneling microscope (hereinafter, shortened to STM), the method disclosed in Ultra microscopy 48 (1993) 433 to 444 is well-known.
The conventional microscopic system which observes a specimen simultaneously by electron microscope and scanning tunneling microscope is shown in FIG.
2
. As clearly understood from
FIG. 2
, the system has a construction which is characterized by a specimen holder H and a scanning tunneling microscope M in one body in a cylindrical electron microscope holder
17
having a window (WD
1
) which allows an electronic beam to pass through and a window (WD
2
) which picks up an electronic beam from a specimen to be observed (SA). And the said microscopic system is also characterized by being attachable to an adequate holding means to insert it in and to remove it from the vacuum chamber. For the observation of a specimen by said two microscopes, after the specimen to be observed SA is set to the specimen holder H, said microscopic system is inserted into a vacuum chamber and fixed, then the specimen and probe
12
of the scanning tunneling microscope are cleaned up by vacuuming the inside of the chamber. However, from the view point of the structural feature of this system, an observation of the specimen which has a clean surface is difficult because the specimen is exposed to the atmosphere. Further in this system, since the cleaning up of the probe of the scanning tunneling microscope and the specimen are carried out at the same time, it is difficult to clean up both two to the desired clean level. And further, it is very difficult to obtain an ultra high vacuum condition.
In
FIG. 2
, the inspection method of the surface of the specimen by said microscopic system is illustrated as follows. That is, the accelerated electronic beam S is irradiated to the surface of specimen through the window WD
1
, the reflected electric beam R from the surface of specimen passes through window WD
2
and the surface of the specimen is observed. meanwhile, the scanning tunneling microscope scans the surface of the specimen by means of probe
12
and inspects the surface of specimen by observing a tunneling electric current.
In general, for the observation of a specimen by an electron microscope and a scanning probe microscope (hereinafter shortened to SPM) represented by a scanning tunneling microscope, it is required to keep high vacuum condition to protect the contamination of the surface of specimen. Further, the probe of scanning probe microscope should be always kept clean. To obtain an accurate scanning probe microscopic image, it is necessary to satisfy the above mentioned two items. Meanwhile, the cleaning conditions which are set up for a probe of scanning probe microscope and for a specimen are different, and if it is necessary to unify the condition, the starting materials of a probe and a kind of specimen must be restricted. Further, as illustrated in the description of the prior art, when considering a case in which a probe and a specimen are combined in one body, the surface of the specimen is contaminated at the cleaning process of the probe, and on the contrary the probe is contaminated at the cleaning process of the specimen. Therefore, it is necessary for both specimen and probe to be cleaned up at the best condition of each, to be maintained at said condition and to be able to be taken out in the atmosphere separately for exchanging.
As an example of the scanning probe microscope except a scanning tunneling microscope, an Atomic Force Microscope (AFM), a Scanning Near-Field Optical Microscope (SNOM), a Scanning Friction Force Microscope (FFM), a Scanning Surface Potential Microscope (SSPM), a Scanning Near-Field Atomic Force Microscope (SNOAM) and a scanning Near-Field Fluorescence Spectroscopy (SNFS) can be mentioned. The theory of these microscopes and construction are well-known. The description referring to the scanning tunneling microscope in this specification and drawings can be applied to the ordinary scanning probe microscope and above mentioned other kind of scanning probe microscope. Therefore, the illustration of the drawing referring to the scanning tunneling microscope must be understood to be related to the ordinary scanning probe microscope and above mentioned other scanning probe microscope.
SUMMARY OF THE INVENTION
The inventors of this invention have combined an electron microscope and a scanning probe microscope so as to make a simultaneous observation by said two different type microscopes possible, and conducted a study to develop a method to clean up a specimen and a probe of the scanning probe microscope under the adequate conditions for each object to be cleaned up even if the conditions for cleaning each of them are different, and accomplished the present invention based on the following knowledge. That is, by connecting independently to an ultra high vacuum electron microscope chamber an ultra high vacuum chamber to which a scanning probe microscope (held to SPM holder) can be inserted and taken out and an ultra high vacuum chamber to which a specimen can be inserted and taken out, makes it possible to clean up the scanning probe microscope and the specimen separately by different conditions.
The object of the present invention is to provide a microscopic system by which a simultaneous observation by an electron microscope and by a scanning probe microscope under ultra high vacuum condition is possible, and the cleaning of a specimen and a probe by different adequate conditions is possible while the chamber of an ultra high vacuum electron microscope is maintained at ultra high vacuum observation condition, and further wherein a specimen and a probe can be changed separately.
The present of this invention is a microscopic system by which the simultaneous observation at an ultra high vacuum condition by an electron microscope and by a scanning probe microscope is possible, and is accomplished by connecting a specimen treatment chamber
5
equipt with a specimen holder
4
on which a specimen is held and an ultra high vacuum chamber
1
for a scanning probe microscope equipt with a scanning probe microscope holder
2
in which scanning probe microscope (SPM) is contained to an ultra high vacuum electron microscope chamber
9
equipt with an observation stage
3
. Observation stage
3
is set up to fix said specimen holder
4
on which a specimen is held which is taken out from said specimen treatment chamber
5
and said scanning probe microscope holder
2
in which scanning probe microscope (SPM) is contained which is taken out from said ultra high vacuum chamber
1
for a scanning probe microscope to the observing position of the main body of the scanning probe microscope and is also equipt with a structural function to irradiate an electronic beam for the observation by the electron microscope to the specimen held on said specimen holder and to take out an electronic beam from said specimen. The ultra high vacuum chamber
1
for a scanning probe microscope and the specimen treatment chamber
5
are separately equipt with a means to transfer and to fix the scanning probe microscope holder
2
and the specimen holder
4
to said observation stage
3
further to remove them from said observation stage and take out from the ultra high vacuum electron microscope chamber
9
. The present invention in a preferred embodiment is characterized by using as the scanning probe microscope, a scanning tunneling. In a further embodiment of the invention the means to transfer and to fix the scanning probe microscope holder
2
and the specimen holder
4
to the ultra high vacuum electron microscope chamber
9
an
Kondo Yukihito
Ohnishi Hideaki
Takayanagi Kunio
Anderson Bruce C.
Japan Science and Technology Corporation
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