Active solid-state devices (e.g. – transistors – solid-state diode – Thin active physical layer which is
Reexamination Certificate
2001-07-02
2004-05-18
Flynn, Nathan J. (Department: 2826)
Active solid-state devices (e.g., transistors, solid-state diode
Thin active physical layer which is
Reexamination Certificate
active
06737668
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method of manufacturing a structure with pores and a structure with pores, and more particularly the structure with pores manufactured by the method of the present invention is usable in a wide range, such as electronic devices, magnetic devices, quantum effect devices as well as optical devices, micro devices, and three-dimensional structures.
2. Related Background Art
<Nano Structure>
A thin film, a fine wire, or a dot made of metal or semiconductor having a size smaller than some characteristic length exhibits sometimes significant electrical, optical or chemical performance because a motion of electrons is confined. From this viewpoint, strong attention has been paid to material having a fine structure (nano structure) smaller than several hundreds nanometer (nm), as functional material.
An example of a method of manufacturing a nano structure is semiconductor processing technology such as fine pattern drawing technology including photolithography, electron beam exposure, and x-ray exposure.
In addition to such technology, there is a new approach to realizing a novel nano structure by using as a base a naturally formed regular structure, i.e., self-ordered structure. This approach has been studied in many fields because it is expected that a structure finer and more specific than a conventional method may be manufactured depending upon the kind of a fine structure used as the base.
An example of such a self-ordering approach is anodic oxidation which can manufacture a nano structure having pores of nano size, easily and with good controllability. For example, anodically oxidized alumina is known which is manufactured by anodically oxidizing aluminum and its alloy in acid solution.
<Anodically Oxidized Alumina>
A porous oxide coating film can be formed by anodically oxidizing an Al plate in acid electrolytic solution (for example, refer to “Nature”, Vol. 337, p.147 (1989) by R. C. Furneaux, W. R. Rigby & A. P. Davidson). The feature of this porous oxide coating film resides in the specific geometric structure that as shown in
FIGS. 11A and 11B
, ultra fine cylindrical pores (nano holes)
11
having a diameter of several nm to several hundreds nm are disposed in parallel at a pitch (cell size) of several nm to several hundreds nm. These cylindrical pores
11
have a high aspect ratio and are excellent in uniformity of cross sectional diameters.
The nano structure can be controlled to some extent by the conditions of anodic oxidation. For example, it is known that the pore pitch, depth and diameter can be controlled to some extent by an anodic oxidation voltage, time and a pore wide process, respectively.
In order to improve verticality, linearity and independency of pores of an anodically oxidized oxide coating film, a two-step anodic oxidization method has been proposed (refer to “Japanese Journal of Applied Physics”. Vol. 35, Part 2, No. 1B, pp. L126 to L129, Jan. 15, 1996). That is, in this two-step anodic oxidization method, after a porous oxide coating film formed thorough anodic oxidation is once removed, anodic oxidation is again performed to form a porous oxide coating film having pores with improved verticality, linearity and independency. This method utilizes the fact that recesses on the surface of an Al plate, which are formed when the anodically oxidized coating film formed by the first anodic oxidation is removed, become starting points of forming pores by the second anodic oxidation.
In order to improve the controllability of shapes, pitches and patterns of pores of a porous oxide coating film, a method of forming starting points of forming pores by using a stamper has also been proposed (refer to Japanese Patent Application Laid-Open No. 10-121292 by Nakao or “Solid Physics” by Masuda, 31, 493 (1996)). That is, in this method, recesses as pore forming start points are formed by pressing a substrate having a plurality of projections on its surface toward an Al plate, and thereafter anodic oxidation is performed to form a porous oxide coating film having pores with improved controllability of shapes, pitches and patterns. Techniques of forming pores not of a honeycomb shape but of a concentrical shape were reported by Ohkubo et al in Japanese Patent Application Laid-Open No. 11-224422.
Another report by Masuda intends to dispose pores in rows by anodically oxidizing an Al film in a film surface direction, the Al film being sandwiched between insulators (refer to “Appl. Phys. Lett.” 63, p. 3155 (1993)).
By paying attention to the specific geometric structure of anodically oxidized alumina, various applications are tried. Although the details of these applications are given by in the explanation by Masuda, some applications will be enumerated below.
For example, there are an application to a coating film by utilizing anti-abrasion and insulation of an anodically oxidized film and an application to a filter made of a peeled-off coating film. Further, by using techniques of filling metal, semiconductor or the like in pores or techniques of forming replicas of pores, various applications are tried to those of coloring, magnetic recording media, EL light emitting elements, electrochronic elements, optical elements, solar batteries, gas sensors and the like. Applications to other fields are also expected, for example, quantum effect devices such as quantum wires and MIM elements, molecule sensors using pores as chemical reaction fields, and the like (refer to “Solid Physics” by Masuda, 31, 493 (1996)).
SUMMARY OF THE INVENTION
A nano structure manufacturing method using semiconductor processing technology (e.g., photolithography technology) is, however, associated with the problems of poor manufacture yield and high system cost. A method capable of manufacturing a nano structure with simple processes and with high reproductivity has been desired. Since photolithography basically utilizes a film forming process and an etching process, it is not suitable for a three-dimensional processing method such as forming a circular pore in parallel to the substrate. From this viewpoint, a self-ordering method, particularly, an anodic oxidation method, is preferable because it can manufacture a nano structure relatively easily and with good controllability and can manufacture a large area nano structure. However, there is a limit in the structure controllability so that applications effectively utilizing the significant structure are not realized as yet.
For example, nano holes (pores) in alumina are generally formed in the surface layer of an Al plate and the direction of each pore is perpendicular to the Al plate surface. Further, as described earlier, although the method of forming pores in parallel to the substrate surface was reported, the shapes of pores are likely to become irregular.
An object of the invention is to solve the above problems and provide a structure with pores with good controllability.
Specifically, an object of the present invention is to control the layout, pitch, position, direction, shape and the like of pores to be formed through anodic oxidation and provide a manufacture method of a nano structure, e.g., a nano structure having pores disposed along a specific direction of a substrate.
Another object of the present invention is to provide a manufacture method for a nano structure having a plurality of pore rows with a specific correlation (e.g. pores in upper and lower rows disposed at the same position or at zigzag positions along the column direction).
Further object of the present invention is to provide a method of filling fillers in pores formed by the above-described methods.
Still another object of the present invention is to provide a novel structure with pores formed by the above-described methods
The above objects can be achieved by the invention as in the following.
According to one aspect of the present invention, there is provided a method of manufacturing a structure with pores (holes) which comprises the steps of: disposing a lamination
Den Tohru
Iwasaki Tatsuya
Canon Kabushiki Kaisha
Fitzpatrick ,Cella, Harper & Scinto
Flynn Nathan J.
Quinto Kevin
LandOfFree
Method of manufacturing structure with pores and structure... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method of manufacturing structure with pores and structure..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method of manufacturing structure with pores and structure... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3185450