Method and device for continuous cold plasma deposition of metal coatings
AssigneeCold Plasma Applications, CPA, SPRL
InventorsPierre Vanden Brande, Alain Weymeersch
Life of this patent
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Abstract
A method for the deposition of a metal layer on a substrate (1) uses a cold plasma inside an enclosure (7) heated to avoid the formation of a metal deposit at its surface. The enclosure has an inlet (21) and an outlet (22) for the substrate with a source of metal vapor between them, made up of an electrode to form a plasma (6) with the substrate or a separate electrically conducting element as a counter-electrode. The deposition metal is introduced in the liquid state in a retention tank (8) and is maintained as a liquid at an essentially constant level during the formation of the metal layer on the substrate. An Independent claim is included for the device used to put this method of coating a substrate into service.
Claims40
Method of depositing a metal coating on a substrate (1), whereby the deposit is applied by cold plasma inside a confinement enclosure (7) heated to prevent a deposit of metal from forming on its surface, this enclosure (7) having an inlet opening (21) and an outlet opening (22) through which the substrate (1) to be coated enters and leaves the latter, a metal vapour source constituting an electrode being provided in this enclosure (7) enabling the plasma to be formed (6) therein, a counter-electrode being formed by the substrate (1) or by a separate electrically conductive element, characterised in that
- the metal needed to produce the coating of metal on the substrate (1) is introduced in the liquid state into a holding tank (8) communicating with the confinement enclosure (7) and
- the liquid metal in this tank (8) is kept at a substantially constant level during the process of forming this metal coating by weighing the holding tank (8),
- the liquid metal being introduced into this tank by means of a tube that is mechanically independent of the holding tank (8),
- wherein the holding tank (8) is supplied from a reservoir of liquid metal (4) external to said enclosure (7) by regulating the difference in pressure prevailing between the interior of the enclosure (7) and a gas present in the reservoir (4).
Device for depositing a metal layer on a substrate (1), comprising
- (a) a confinement enclosure (7) with an inlet opening (21) and an outlet opening (22) through which the substrate (1) to be coated with the metal layer can enter and leave this enclosure (7),
- (b) means for heating the walls of this enclosure (7),
- (c) at least one holding tank (8) for a liquid metal communicating with this enclosure (7) and constituting an electrode,
- (d) a counter-electrode formed by the substrate (1) or by a separate electrically conductive element (20) and
- (e) means for generating a plasma (6) in this enclosure (7) at least above the liquid metal,
- whereby (f) means are provided for keeping the liquid metal at a substantially constant level, these means comprising a regulating device enabling the level of the liquid metal in the holding tank (8) to be controlled by weighing, and
- whereby (g) a supply tube (5) for the liquid metal is provided opening into the holding tank (8), this tube (5) being mechanically independent of the holding tank (8), whereby (h) it has a reservoir (4), communicating with the holding tank (8), containing the liquid metal, the level of which is lower than the level of liquid metal in the holding tank (8), means being provided to supply the holding tank (8) with liquid metal from said reservoir (4) on a substantially constant basis.
Method of depositing a metal coating on a substrate (1), whereby the deposit is applied by cold plasma inside a confinement enclosure (7) heated to prevent a deposit of metal from forming on its surface, this enclosure (7) having an inlet opening (21) and an outlet opening (22) through which the substrate (1) to be coated enters and leaves the latter, a metal vapour source constituting an electrode being provided in this enclosure (7) enabling the plasma to be formed (6) therein, a counter-electrode being formed by the substrate (1) or by a separate electrically conductive element, characterised in that
- the metal needed to produce the coating of metal on the substrate (1) is introduced in the liquid state into a holding tank (8) communicating with the confinement enclosure (7) and
- the liquid metal in this tank (8) is kept at a substantially constant level during the process of forming this metal coating by weighing the holding tank (8),
- the liquid metal being introduced into this tank by means of a tube that is mechanically independent of the holding tank (8),
- wherein the holding tank (8) is supplied from a reservoir of liquid metal (4), in which the level of the metal is lower than the level of the liquid metal in the holding tank (8), by regulating the height of the reservoir (4) depending on the level of the metal in the holding tank (8).
Device for depositing a metal layer on a substrate (1), comprising
- (a) a confinement enclosure (7) with an inlet opening (21) and an outlet opening (22) through which the substrate (1) to be coated with the metal layer can enter and leave this enclosure (7),
- (b) means for heating the walls of this enclosure (7),
- (c) at least one holding tank (8) for a liquid metal communicating with this enclosure (7) and constituting an electrode,
- (d) a counter-electrode formed by the substrate (1) or by a separate electrically conductive element (20) and
- (e) means for generating a plasma (6) in this enclosure (7) at least above the liquid metal,
- whereby (f) means are provided for keeping the liquid metal at a substantially constant level, these means comprising a regulating device enabling the level of the liquid metal in the holding tank (8) to be controlled by weighing, and
- whereby (g) a supply tube (5) for the liquid metal is provided opening into the holding tank (8), this tube (5) being mechanically independent of the holding tank (8),
- wherein (h) the supply tube (5) for the liquid metal extends through a wall of the holding tank (8), a clearance being provided between the wall and the tube (5) of a dimension such that the metal is not able to flow through this clearance due to the surface tension of the metal yet allows the holding tank (8) and the tube (5) to move freely relative to one another.
Dependencies are inferred from the claim text.