Device for carrying out a plasma-assisted process

Abstract

A device for carrying out a plasma enhanced process includes, within a vacuum chamber, at least one magnetron electrode ( 32 ) constituting an unbalanced magnetron having a flat magnetron face ( 20 ) with peripheral and central magnetic poles of opposite polarities connected to a source ( 34 ) of alternating voltage. The device further includes a device for positioning a substrate ( 25 ), the substrate having a surface to be treated facing the magnetron face ( 20 ), and a gas supply device for supplying a process gas or process gas mixture to the space between the magnetron face ( 20 ) and the treated surface. The distance between the magnetron face ( 20 ) and the treated surface is adapted to the magnetic field created by the magnetron electrode ( 32 ) such that there is a visible plasma band running between darker tunnels formed by magnetic field lines extending between peripheral and central magnetic poles of the magnetron face ( 20 ) and the treated surface, the plasma band having a minimum width but having homogeneous brightness towards the treated surface.

1 . A device for carrying out a plasma enhanced process, the device comprising within a vacuum chamber a magnetron electrode ( 32 ), a positioning means and a gas supply means, the magnetron electrode comprising a flat magnetron face ( 20 ) with peripheral and central magnetic poles of opposite polarities and further comprising means for producing a high frequency alternating electric field, the positioning means being equipped for positioning a substrate ( 25 ) with a surface to be treated facing the magnetron face ( 20 ) and the gas supply means being equipped for supplying a process gas or process gas mixture to the space between the magnetron face ( 20 ) and the surface to be treated, wherein the magnetron electrode ( 32 ) is of the unbalanced type and that a distance between the magnetron face ( 20 ) and the positioning means is adapted to the magnetic field created by the magnetron electrode ( 32 ) such that there is a visible plasma band running between darker tunnels ( 11 ) formed by magnetic field lines ( 10 ) extending between peripheral and central magnetic poles of the magnetron face ( 20 ) and the surface to be treated, the plasma band having a minimum width but having towards the surface to be treated a homogeneous brightness.  
     
     
         2 . The device according to  claim 1 , wherein a distance (A-C) between the surface to be treated and the magnetron face ( 20 ) is at least 2% larger than a visible height (A-B) of the tunnels ( 11 ).  
     
     
         3 . The device according to  claim 1 , wherein a distance (A-C) between the surface to be treated and the magnetron face ( 20 ) is at most 20% larger than a visible height (A-B) of the tunnels ( 11 ).  
     
     
         4 . The device according to  claim 1 , wherein a magnetic strength of the central magnetic pole of the magnetron face ( 20 ) is about half of a magnetic strength of the peripheral pole.  
     
     
         5 . The device according to  claim 1 , wherein the magnetron electrode ( 32 ) comprises an electrode element ( 21 ) being connected to a source of an alternating voltage ( 34 ).  
     
     
         6 . The device according to  claim 5 , wherein the positioning means and/or the substrate ( 25 ) are arranged to be electrically grounded, electrically floating or negatively biased.  
     
     
         7 . The device according to  claim 1 , wherein the positioning means is a rotating drum ( 30 ) and wherein a plurality of magnetron electrodes ( 32 ) having rectangular faces arranged with their length parallel to the rotation axis of the drum ( 30 ) are arranged around part of a circumference of the drum ( 30 ).  
     
     
         8 . The device according to  claim 7 , wherein the gas supply means comprises gas supply lines ( 33 ) extending parallel to the drum axis between the magnetron faces ( 20 ).  
     
     
         9 . The device according to  claim 7 , wherein each of the plurality of magnetrons ( 32 ) is connected to a separate power supply.  
     
     
         10 . Use of the device according to  claim 1  for carrying out a plasma enhanced chemical vapour deposition process.  
     
     
         11 . Use of the device according to  claim 1  for depositing silicon oxide using a process gas comprising an organosilicon compound and oxygen.  
     
     
         12 . Use according to  claim 11 , wherein the substrate is a web of polymer film material being coated so as to improve barrier properties of said web of polymer film material.