DE3919147A1 - Plasma coating plastic substrates with aluminium - using target made of aluminium alloy contg. silicon to improve adhesion of coating to plastic - Google Patents

Abstract

Plastic substrates (1) are coated with A1 by sputter coating using an evacuation chamber (15,15a) with an electrode (5) electrically connected to a target (3) made of an A1 alloy containing 0.5-2.0% Si and 99.5-98.0% Al. USE/ADVANTAGE - Esp. for coating polycarbonate surfaces without using an intermediate or adhesive layer. The Si improves the adhesion of the A1 alloy to the plastic and improves the corrosion resistance of the coating by reducing the deep oxidation.

Description

The invention relates to a device for coating a substrate, preferably a plastic substrate, with aluminum, consisting of a direct current source, which with a in an evacuable coating chamber arranged electrode is connected, the elek is connected to a target that atomizes and its atomized particles settle on the substrate knock down, being in the coating chamber Process gas can be introduced.

In known methods, an aluminum layer is unmit telbar on the plastic substrate, for. B. on polycarbonate, sputtered on, without an interim or detention layer.  

This method has the disadvantage that the Oxidationsbe durability of aluminum is very limited, d. H. that it for example when the coated sub is stored for a long time experience has shown that stratified corrosion occurs can.

The present invention therefore has the object reason to create a device that is suitable the lifespan of a sputtered aluminum layer to improve the plastic substrate significantly without conventional or existing devices or Systems are unsuitable for this or without this significant or costly conversions or changes must be made.

This object is achieved in that the Alloy to be atomized from 0.5 to 2.0% silicon and 99.5 to 98.0% aluminum is formed.

The invention allows for a wide variety of designs to; one of them is in the attached drawing schematically shown in more detail that a sputter system for that shows DC sputtering.

In the drawing, a substrate 1 is shown, which is to be provided with a thin, electrically conductive layer 2 . This substrate 1 is opposite a target 3 , which is to be atomized. The target 3 is connected via a section U-shaped element 4 to an electrode 5 , which rests on a yoke 6 , which includes three permanent magnets 7 , 8 , 9 between itself and the element 4 . The polarities of the poles of the three permanent magnets 7 , 8 , 9 directed at the target 3 alternate, so that the south poles of the two outer permanent magnets 7 , 9 with the north pole of the central permanent magnet 8 each cause an approximately circular magnetic field through the target 3 . This magnetic field compresses the plasma in front of the target 3 , so that it has its greatest density where the magnetic fields have the maximum of their circular arc. The ions in the plasma are accelerated by an electric field that builds up on the basis of a direct voltage that is indicated by a direct current source 10 . This direct current source 10 is connected with its negative pole via two inductors 11 , 12 to the electrode 5 . The electric field is perpendicular to the surface of the target 3 and accelerates the positive ions of the plasma towards this target. As a result, more or fewer atoms or particles are knocked out of the target 3 , in particular from the areas 13 , 14 where the magnetic fields have their maxima. The atomized atoms or particles migrate towards the substrate 1 , where they are deposited as a thin layer 2 .

A process computer can be provided to control the arrangement shown, which processes measurement data and issues control commands. For example, the values of the measured partial pressure in the process chamber 15 can be fed to this process computer. Based on this and other data, he can, for example, regulate the gas flow via the valves 18 , 19 and adjust the voltage at the cathode. The process computer is also able to regulate all other variables, for example cathode current and magnetic field strength. Since such process computers are known, a description of their structure is omitted.

In order to improve the corrosion resistance of the layer 2 on the substrate 1 , the target 3 is formed from an alloy of 0.5 to 2.0% silicon and 99.5 to 98.0% aluminum.

A significant increase in layer quality in terms of a decrease in deep oxidation and barrier characteristics compared to a conventional target Pure aluminum is the result.

List of items

1 substrate
2 layer
3 target
4 U-shaped element
5 electrode
6 yokes
7 permanent magnet
8 permanent magnet
9 permanent magnet
10 DC power source
11 inductance
12 inductance
13 Sputtergraben (area)
14 Sputtergraben (area)
15, 15 a room, coating chamber
16 gas containers
17 gas tanks
18 valve
19 valve
20 inlet connection
21 inlet connection
22 gas supply line
23 gas supply line
24 containers
25 containers, process chamber
26 aperture
27 electrical connection (ground line)
28 electrical connection
29 capacitor

Claims (1)

Device for coating a substrate, preferably as a plastic substrate ( 1 ), with aluminum, consisting of a direct current source ( 10 ) which is connected to an electrode ( 5 ) which is arranged in an evacuable coating chamber ( 15 , 15 a) and which is electrically connected to a Target ( 3 ) is connected, which is atomized and its atomized particles are deposited on the substrate ( 1 ), whereby a process gas can be introduced into the coating chamber ( 15 , 15 a), characterized in that the target to be atomized ( 3 ) is formed from an alloy of 0.5 to 2.0% silicon and 99.5 to 98.0% aluminum.