Coating processes – Direct application of electrical – magnetic – wave – or... – Plasma
Reexamination Certificate
2002-07-22
2004-12-28
Chen, Bret (Department: 1762)
Coating processes
Direct application of electrical, magnetic, wave, or...
Plasma
C427S576000, C427S553000, C427S162000
Reexamination Certificate
active
06835425
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a method of forming various function of layers having high quality, a product with the layer, an optical film with the layer which is an anti-reflection layer, a dielectric coated electrode suitable for forming the layer, and a plasma discharge apparatus comprising the dielectric coated electrode, and particularly to a method of forming a layer on a substrate comprising generating a reactive gas in a plasma state at atmospheric pressure or approximately atmospheric pressure and exposing the substrate to the reactive gas in a plasma state to form a layer on the substrate, a product with the layer, an optical film, a dielectric coated electrode, and a plasma discharge apparatus.
BACKGROUND OF THE INVENTION
Many materials in which a layer with high function is provided on a substrate are used in various kinds of products, for example, an LSI, a semi-conductor, a displaying device, a magnetic recording device, light to electricity conversion device, a Josephson device, a solar battery, and a light heat conversion device. Examples of the layer with high function include an electrode layer, a dielectric protective layer, a semi-conductor layer, a transparent electro-conductive layer, an electrochromic layer, a fluorescent layer, a superconduction layer, a dielectric layer, a solar battery layer, an anti-reflection layer, an anti-abrasion layer, an optical interference layer, a reflection layer, an anti-static layer, an electroconductive layer, an anti-stain layer, a hard coat layer, a subbing layer, a barrier layer, an electromagnetic radiation shielding layer, an infrared ray shielding layer, a UV absorption layer, a lubricant layer, a shape-memory layer, a magnetic recording layer, a light emission element layer, a layer applied to organisms, an anti-corrosion layer, a catalyst layer, a gas-sensor layer, and a layer for decoration. These layers with high function are formed according to a wet coating method such as a solution coating method or according to a dry coating method employing vacuum processing such as a spattering method, a vacuum evaporation method or an ion plating method.
The solution coating method is advantageous in high productivity, but is not necessarily suitable for formation of a layer with high function, since it is necessary to dissolve or disperse materials constituting the layer in a solvent to prepare a coating solution, and when the coating solution is coated on a substrate to form a layer, the solvent used remains in the resulting layer or it is difficult to obtain a layer with a uniform thickness. The solution coating method further has problem in that at the drying process after coating, the solvent evaporated from the coating solution pollutes environment.
On the other hand, the dry coating method employing vacuum processing can provide a layer with high precision and is preferable in forming a layer with high function. However, the dry coating method, when a substrate to be processed is of large size, requires a large-scale vacuum processing apparatus, which is too expensive and time-consuming for evacuation, resulting in disadvantage of lowering of productivity. As a method for overcoming the demerits in that the solution coating method is difficult to provide a layer with high function or use of a vacuum processing apparatus results in lowering of productivity, a method is described in Japanese Patent O.P.I. Publication Nos. 11-133205, 2000-185362, 11-61406, 2000-147209, and 2000-121804, which comprises subjecting a reactive gas to discharge treatment at atmospheric pressure or approximately atmospheric pressure, exciting the reactive gas to a plasma state and forming a layer on a substrate (hereinafter referred to also as an atmospheric pressure plasma method). The atmospheric pressure plasma method disclosed in these publications generates discharge plasma between two opposed electrodes by applying pulsed electric field with a frequency of from 0.5 to 100 kHz and with a strength of electric field of from 1 to 100 V/cm. However, although a layer with high function can be formed in only a small area according to the atmospheric pressure plasma method disclosed in the aforementioned publications, it is difficult to form a uniform layer over a large area. Further, it has been proved that the layer formed does not sufficiently satisfy performance to be required for a layer with high function. Accordingly, a means for solving these problems occurring in the layer formation as described above has been required.
The present invention has been made in view of the above. An object of the invention is to provide a method of uniformly forming a layer with high function over a large area with high productivity and with high production efficiency, a product comprising the layer, and an optical film comprising the layer, and to provide a dielectric coated electrode and a plasma discharge apparatus for carrying out the method and obtaining the product and the optical film.
DISCLOSURE OF THE INVENTION
The above object of the invention can be attained by each of the following constitutions:
(1) A layer forming method comprising the steps of supplying power of not less than 1 W/cm
2
at a high frequency voltage exceeding 100 kHz across a gap between opposed electrodes at atmospheric pressure or at approximately atmospheric pressure to induce a discharge, generating a reactive gas in a plasma state by the charge, and exposing a substrate to the reactive gas in a plasma state to form a layer on the substrate.
(2) The layer forming method as described in item (1), wherein the total power supplied to the electrode exceeds 15 kW.
(3) The layer forming method as described in item (1) or (2), wherein the high frequency voltage has a continuous sine-shaped wave.
(4) The layer forming method as described in any one of items (1) through (3), wherein the substrate is relatively transported to at least one of the electrodes, whereby the layer is formed on the substrate.
(5) The layer forming method as described in any one of items (1) through (4), wherein the substrate is placed between the electrodes, and the reactive gas is introduced to the gap between the electrodes, whereby the layer is formed on the substrate.
(6) The layer forming method as described in item (4) or (5), wherein the length in the transverse direction of a discharge surface of the electrodes is equal to or greater than that in transverse direction of the substrate on which a layer is to be formed, the transverse direction being perpendicular to the transport direction.
(7) The layer forming method as described in item (6), wherein the length in the transport direction of a discharge surface of the electrode is not less than one tenth the length in the transverse direction of a discharge surface of the electrode.
(8) The layer forming method as described in item (7), wherein the discharge surface area of the electrode is not less than 1000 cm
2
.
(9) The layer forming method as described in any one of items (1) through (8), wherein at least one on one side of the electrodes is a dielectric coated electrode whose discharge surface is coated with a dielectric to form a dielectric layer.
(10) The layer forming method as described in item (9), wherein the dielectric layer is one formed by thermally spraying ceramic to form a ceramic layer and sealing the ceramic layer with an inorganic compound.
(11) The layer forming method as described in item (10), wherein the ceramic is alumina.
(12) The layer forming method as described in item (10) or (11), wherein the inorganic compound for the sealing is hardened by a sol-gel reaction.
(13) The layer forming method as described in item (12), wherein the sol-gel reaction is accelerated by energy treatment.
(14) The layer forming method as described in item (13), wherein the energy treatment is heat treatment at not more than 200° C. or UV irradiation treatment.
(15) The layer forming method as described in any one of items (12) through (14), wherein the inorganic compound for the sealing after the sol-gel reactio
Fukuda Kazuhiro
Iwamaru Shunichi
Kondo Yoshikazu
Murakami Takashi
Muramatsu Yumi
Chen Bret
Frishauf Holtz Goodman & Chick P.C.
Konica Corporation
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