Radiant energy – Inspection of solids or liquids by charged particles
Reexamination Certificate
2002-07-26
2004-09-07
Lee, John R. (Department: 2881)
Radiant energy
Inspection of solids or liquids by charged particles
C250S234000, C250S310000, C250S311000, C156S272200, C422S198000, C073S105000, C073S104000
Reexamination Certificate
active
06787769
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a probe for a scanning type microscope which images a surface structure of a specimen, by using a conductive nanotube as a probe needle. More particularly, the present invention relates to a probe for a conductive scanning type microscope in which a conductive nanotube and a cantilever are electrically connected by coating both of them with a conductive deposit, a conductive film and a conductive coating film, and relates further to a machining method using the same, wherein a voltage can be applied between the conductive nanotube and a specimen so that a current flows.
BACKGROUND ART
In order to image a surface structure of a specimen by means of an atomic force microscope abbreviated as AFM, a probe needle is needed which is caused to approach to the surface of the specimen and to obtain information from it. As the probe needle, a cantilever made of silicon or silicon-nitride, which has a protruding portion (or pyramid portion) at the tip end, has been known in the past.
A conventional cantilever is formed by means of the micro-fabrication technique such as lithography, etching, etc. Since the cantilever detects atomic force from the surface of specimen by the tip end of protruding portion, the degree of clearness of an image is determined by the degree of sharpness of the tip end. Then, in the sharpening treatment of the tip end of the protruding portion which serves as a probe needle, an oxide process using a semi-conduction treatment technique and an etching process of an oxide film are utilized. However, there is a lower limit in the reduction of size even in the semi-conductor treatment technique, so that the degree of sharpness of the tip end of the protruding portion above-described is also physically limited.
On the other hand, a carbon nanotube was discovered as a carbon matter having a new structure. The carbon nanotube is from about 1 nm to several 10 nm in diameter and several &mgr;m in length, and its aspect ratio is about 100~1000. It is difficult to form a probe needle of 1 nm diameter by the present technique of semiconductor. Therefore, in this respect, the carbon nanotube provides best condition for the probe needle of the AFM.
In such a situation, H. Dai and others published, in Nature (Vol.384, Nov. 14, 1996), a report with respect to the AMF probe in which a carbon nanotube is stuck on the tip of the protruding portion of a cantilever. Though the probe proposed by them was of epoch-making, the carbon nanotube fell off from the protruding portion during repeatedly scanning surfaces of specimens, since the carbon nanotube was simply stuck on the protruding portion.
In order to solve this weak point, the present inventors have achieved to develop a method fastening firmly the carbon nanotube to the protruding portion of the cantilever. Results of this invention have been published; first fastening method as the publication No.2000-227435, and second fastening method as the publication No.2000-249712.
The first fastening method above-mentioned is that a coating film is formed by means of irradiating an electron beam to the base end portion of a nanotube, and next the nanotube is fastened to the cantilever by means of coating the nanotube with the coating film. The second method is that the base end portion of the nanotube is fusion-fastened to the protruding portion of the cantilever by means of irradiating an electron beam on the base end portion of the nanotube or by means of electrically transmitting it.
As a marketed cantilever, as previously mentioned, is manufactured by means of the semiconductor process-technique, its material is silicon or silicon-nitride. The silicon-nitride is insulator, though the silicon is semi-conductor. It, therefore, was incapable to apply a voltage or to flow current the between the probe needle of the conductive nanotube and a specimen, even if conductive nanotubes such as carbon nanotube, etc. was fastened to the protruding portion of the cantilever, since the cantilever itself had not conductivity.
In a case that a probe has not conductivity, it means that uses of the probe is much limited. For example, the probe can not be used for a scanning tunnel microscope, as the tunnel microscope images a specimen by detecting a tunnel current between the probe needle and the specimen.
Furthermore, by using this probe, it is unable to heap up atoms on the surface of a specimen, to transfer or to take out atoms form the surface of a specimen. In order to process a specimen by means of operating atoms in this manner, it is necessary to apply a voltage to the probe needle. The technique of nano-process is thought as a fundamental technology as well as bio-technology in the 21 century. Hence, the utility of a probe will be much limited in the future, without solving this problem.
Accordingly, an object of the present invention is to realize a probe for a conductive scanning type microscope in which a voltage is applicable and a current can flows between a conductive nanotube and a specimen, by means of electrically connecting cantilever and a probe needle which comprise the conductive nonotube.
DISCLOSURE OF INVENTION
The present invention provides, in a probe for a scanning type microscope, by which substance information of a specimen is obtained by means of a tip of a probe needle of a conductive nanotube fastened to a cantilever; a probe for a conductive scanning type microscope characterized in that a conductive nanotube and a conductive film are caused to be electrically transmitted by means of a conductive resolution deposit of organic gas, wherein the probe comprises a conductive films formed on the surface of said cantilever, the conductive nanotube, a base end portion of which is disposed in contact with a specified portion of the surface of the cantilever, and the conductive resolution deposit with which the conductive nanotube is fastened by coating from the base end portion of the conductive nanotube to a part of said conductive films.
The present invention provides, in a probe for a scanning type microscope which obtains substance information of a specimen surface through the tip of a conductive nanotube probe needle fastened to a cantilever; a probe for a conductive scanning type microscope characterized in that a conductive nanotube and a conductive film are caused to be electrically transmitted by means of a conductive deposit, wherein said probe comprises a conductive films formed on the surface of said cantilever, a conductive nanotube, a base end portion of which is disposed in contact with a specified surface portion of this conductive film, and a conductive deposit, with which the base end portion of the conductive nanotube is coated in order to fasten it.
The present invention provides a probe for a conductive scanning microscope described in the first and second parts of the present invention, wherein the conductive state between the conductive nonotube and the cantilever is made accurate by means of furthermore forming a conductive coating film on said conductive deposit, so that the coating film reaches to both the conductive nanotube and the conductive film.
The present invention provides, in a probe for a conductive scanning type microscope which obtains substance information of a surface of a specimen through the tip portion of a conductive nanotube probe needle adhered to a cantilever; a probe for a conductive scanning type microscope which is characterized in that a conductive nanotube and a cantilever are caused to be in a electrically transmitted state, wherein the probe comprises a conductive nanotube, the base end portion of which is disposed in contact with the specified surface portion of said cantilever, a conductive deposit with which a conductive nanotube is fastened to a cantilever by coating the base end portion of it, and a conductive coating film is formed so that it covers this conductive deposit and reaches both the conductive nanotube and the cantilever surface.
The present invention provides a probe for a conductive scanning type microscope
Akita Seiji
Harada Akio
Nakayama Yoshikazu
Okawa Takashi
Shirakawabe Yoshiharu
Hashmi Zia R.
Koda & Androlia
Lee John R.
Nakayama Yoshikazu
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