US 5,250,328 A · Process and apparatus for plasma CVD coating or plasma treating substrates

Abstract

To provide large-surface substrates economically and in a short time, with coatings which are to be more impenetrable and more homogeneous than conventionally produced coatings, a plasma CVD process is employed in which a reaction gas capable of depositing a coating material therefrom flows over the surface to be coated and the reaction gas is excited into a band-shaped plasma by microwaves fed from two microwave feeds, in a device comprising end walls (2, 3) and a waveguide (1) with a square cross-section in which two standing waves polarized perpendicular to one another are excited and are shifted relative to one another by one-quarter wavelength, the coupling of the microwaves to the plasma being performed by a lengthwise slit (6) made in one of the edges of waveguide (1), with two crossed microwave polarizers (4, 5) being positioned in waveguide (1), such that each polarizer can be penetrated by the microwaves from the feed (7, 8) adjacent thereto and cannot be penetrated by the microwaves from the feed (7, 8) not proximate thereto, with the distance between an end wall (2, 3 ) and the polarizer (4, 5) proximate thereto being selected so as to form standing waves.

Claims30

Dependent claims

A process for treating or coating a substrate which comprises passing over the substrate a stream of a reaction gas, which is capable when excited of depositing a substance therefrom onto the substrate, flows over the surface to be treated or coated and exciting the reaction gas to a band-shaped plasma by microwaves generated in a waveguide, thereby treating the surface or depositing a coating thereon, by:

(a) exciting two standing waves of wavelengths .lambda..sub.h1 and .lambda..sub.h2 which are polarized perpendicular to one another, and shifting them relative to each other by one-quarter wavelength, in a waveguide means that is square in cross section;
and
(b) coupling the microwaves to the plasma by a lengthwise slit provided in one of the edges of the waveguide means.

A device for treating or coating a surface of a substrate in which a stream of a reaction gas, which is capable when excited of depositing a substance therefrom onto the substrate, flows over the surface to be treated or coated and the reaction gas is excited to a band-shaped plasma by microwaves generated in a waveguide, which device comprises a reaction space for receiving a substrate to be treated or coated, a gas inlet connected to a source of the reaction gas for feeding reaction gas thereinto and reaction gas excitation means adjacent to the reaction space in which microwaves of wavelengths .lambda..sub.h1 and .lambda..sub.h2, respectively, are excited, whereby a surface of a substrate positioned in the stream of the reaction gas is treated or is coated with the substrate deposited, which reaction gas excitation means comprises:

(a) a waveguide with a first end closed by a first end wall and a second end closed by a second end wall;
(b) first and second microwave polarizers which are crossed and which are positioned in the waveguide at a distance l.sub.1 =.lambda..sub.h2 /2 (n+1/2);
and
(c) first and second microwave feeds for feeding the microwaves and positioned, respectively, between the first end wall and the first polarizer, and between the second end wall and the second polarizer, so that each polarizer can be penetrated by the microwaves fed from the polarizer which is positioned closest thereto and cannot be penetrated by the microwaves fed from the feed which is positioned away therefrom;
and wherein
(i) the distance between an end wall and the polarizer positioned away therefrom in each case permits the formation of standing waves, and
(ii) the waveguide has a square cross section and a lengthwise edge which, in the area between the polarizers, has a coupling slit therein of a length s and a width b.sub.1 and which is closed relative to the reaction space and has a window therein formed of material through which the microwaves can penetrate.

4 more elements

Dependencies are inferred from the claim text.

Process and apparatus for plasma CVD coating or plasma treating substrates

Life of this patent

Process and apparatus for plasma CVD coating or plasma treating substrates

Life of this patent

Abstract

Claims30